HomeMy WebLinkAboutAppendix N - PDP SWQMP
PDP SWQMP Template Date: March 2019
PDP SWQMP
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN (SWQMP)
Project Name ______________________________
Assessor’s Parcel Number(s) ________________________________________
Permit Application Number _____________________________________
Drawing Numbers ___________________________________
CIVIL ENGINEER NAME: _________________________________________; PE #___________
________________________________________
Wet Signature and Stamp
PREPARED FOR: Applicant Name: ___________________________________
Address: _________________________________________
__________________________________________
Telephone # ______________________________________
PREPARED BY: Company Name: ___________________________________
Address: _________________________________________
_________________________________________
Telephone # ______________________________________
DATE:
____________________________________________________________________________________
Approved By: City of Chula Vista Date:
(print Name & Sign)
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\SWQMP
Job# 4409.02
City of San Diego
PTS#647766
Page intentionally left blank for double-sided printing
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
TABLE OF CONTENTS
The checklist on this page summarized the table and attachments to be included with this PDP SWQMP
Submittal. Tables & attachments with boxes already checked ( ) are required for all Projects
Acronym Sheet
Certification Page
Submittal Record
Project Vicinity Map
Attach a copy of the Intake Form: Storm Water Requirements Applicability Checklist
HMP Exemption Exhibit (if Applicable)
FORM I-3B Site Information Checklist for PDPs
FORM I-4: Source Control BMP Checklist for All Development Projects
FORM I-5: Site Design BMP Checklist for All Development Projects
FORM I-6: Summary of PDP Structural BMPs
ATTACHEMNT 1: Backup for PDP Pollutant Control BMPs
Attachment 1A: DMA Exhibit
Attachment 1B: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1C: FORM I-7 Harvest and Use Feasibility Screening (when applicable)
Attachment 1D: Infiltration Information Attachment 1E: Pollutant Control BMP Design
Worksheets / Calculations for each DMA and Structural BMP Worksheets from Appendix
B, as applicable
ATTACHMENT 2: Backup for PDP Hydromodification Control Measures
➢ Attachment 2A: Hydromodification Management Exhibit
➢ Attachment 2B: Management of Critical Coarse Sediment Yield Areas
➢ Attachment 2C: Geomorphic Assessment of Receiving Channels
➢ Attachment 2D: Flow Control Facility Design; Overflow Design Summary for each
structural BMP
ATTACHMENT 3: Structural BMP Maintenance Plan
ATTACHMENT 4: Copy of Plan Sheets Showing Permanent Storm Water BMPs
ATTACHMENT 5: Project’s Drainage Report
ATTACHMENT 6: Project’s Geotechnical and Groundwater Investigation Report
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ACRONYMS
APN Assessor's Parcel Number
BMP Best Management Practice
HMP Hydromodification Management Plan
HSG Hydrologic Soil Group
MS4 Municipal Separate Storm Sewer System
N/A Not Applicable
NRCS Natural Resources Conservation Service
PDP Priority Development Project
PE Professional Engineer
SC Source Control
SD Site Design
SDRWQCB San Diego Regional Water Quality Control Board
SIC Standard Industrial Classification
SWQMP Storm Water Quality Management Plan
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Certification Page
Project Name: ______________________________________
Permit Application Number: ________________________________________
I hereby declare that I am the Engineer in Responsible Charge of design of storm water best
management practices (BMPs) for this project, and that I have exercised responsible charge over the
design of the BMPs as defined in Section 6703 of the Business and Professions Code, and that the
design is consistent with the PDP requirements of the City of Chula Vista BMP Design Manual, which
is based on the requirements of the San Diego Regional Water Quality Control Board Order No. R9-
2013-0001 as amended by R9-2015-0001 and R9-2015-0100 (MS4 Permit).
I have read and understand that the City Engineer has adopted minimum requirements for managing
urban runoff, including storm water, from land development activities, as described in the BMP
Design Manual. I certify that this PDP SWQMP has been completed to the best of my ability and
accurately reflects the project being proposed and the applicable BMPs proposed to minimize the
potentially negative impacts of this project's land development activities on water quality. I understand
and acknowledge that the plan check review of this PDP SWQMP by the City Engineer is confined
to a review and does not relieve me, as the Engineer in Responsible Charge of design of storm water
BMPs for this project, of my responsibilities for project design.
_________________________________________________, _______________________
Engineer of Work's Signature Date
__________________________, ___________________________
PE # Expiration Date
________________________________________________________
Print Name
________________________________________________________
Company
Engineer's Seal
Nakano
Chelisa Pack
Project Design Consultants
6/30/2371026
1/9/2023
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
SUBMITTAL RECORD
Use this Table to keep a record of submittals of this PDP SWQMP. Each time the PDP SWQMP is
re-submitted, provide the date and status of the project. In column 4 summarize the changes that have
been made or indicate if response to plancheck comments is included. When applicable, insert
response to plancheck comments behind this page.
Submittal
Number
Date Project Status Summary of Changes
1 Preliminary Design /
Planning/ CEQA
Final Design
Initial Submittal
2 Preliminary Design /
Planning/ CEQA
Final Design
3 Preliminary Design /
Planning/ CEQA
Final Design
4 Preliminary Design /
Planning/ CEQA
Final Design
2nd Submittal- Revised Site Plan
to add secondary access & avoid
Caltrans drainage easement
5 1/9/23 Preliminary Design 5th Submittal -
Updated to include
additional City of
SD-formatted
version of infiltration
feasibility letter in
Att 1D
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Project Vicinity Map
NO SCALE
TIJUANA
BROWN
FIELD
VICINITY MAP
598,514566445
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
HMP Exemption Exhibit
Attach this Exhibit (if Applicable) that shows direct storm water runoff discharge from the project
site to HMP exempt area. Include project area, applicable underground storm drains line and/or
concrete lined channels, outfall information and exempt waterbody. Reference applicable drawing
number(s). Exhibit must be provided on 11"x17" or larger paper.
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 1
Backup for PDP Pollutant Control BMPs
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Indicate which Items are Included:
Attachment
Sequence
Contents Checklist
Attachment 1A DMA Exhibit (Required)
See DMA Exhibit Checklist. Included
Attachment 1B
Tabular Summary of DMAs Showing DMA ID
matching DMA Exhibit, DMA Area, and DMA Type
(Required)*
*Provide table in this Attachment OR on DMA
Exhibit in Attachment 1a
Included on DMA Exhibit
in Attachment 1A
Included as Attachment 1B,
separate from DMA
Exhibit
Attachment 1C
Form I-7, Harvest and Use Feasibility Screening
Checklist (Required unless the entire project will use
infiltration BMPs)
Refer to Appendix B.3-1 of the BMP Design Manual
to complete Form I-7.
Included
Not included because the
entire project will use
infiltration BMPs
Attachment 1D
Infiltration Feasibility Information. Contents of
Attachment 1D depend on the infiltration condition:
No Infiltration Condition:
Infiltration Feasibility Condition
Letter (Note: must be stamped & signed by
licensed geotechnical engineer)
Form I-8A (optional)
Form I-8B (optional)
Partial Infiltration Condition:
Infiltration Feasibility Condition
Letter (Note: must be stamped & signed by
licensed geotechnical engineer)
Form I-8A
Form I-8B
Full Infiltration Condition:
Form I-8A
Form I-8B
Worksheet C.4-3
Form I-9
Refer to Appendices C and D of the BMP Design
Manual for guidance.
Included
Not included because the
entire project will use
harvest and use BMPs
Attachment 1E
Pollutant Control BMP Design Worksheets/
Calculations (Required)
Refer to Appendices B and E of the BMP Design
Manual for structural pollutant control BMP design
guidelines
Included
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Use this checklist to ensure the required information has been
included on the DMA Exhibit:
The DMA Exhibit must identify all the following:
Underlying hydrologic soil group
Approximate depth to groundwater
Existing natural hydrologic features (watercourses, seeps, springs, wetlands)
Critical coarse sediment yield areas to be protected
Existing topography and impervious areas
Existing and proposed site drainage network and connections to drainage offsite
Proposed grading
Proposed impervious features
Proposed design features and surface treatments used to minimize imperviousness
Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square
footage or acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating)
Potential pollutant source areas and corresponding required source controls (see Chapter 4,
Appendix E.1, and Form I-3B)
Structural BMPs (identify location, type of BMP, and size/detail, and include cross-sections)
ATTACHMENT 1A,1B – DMA MAP
T O R
T
O
R
T O R
T
O
R
T O R
T
O
R
T O R
T
O
R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
T O RTORTORTORTOR
T O R T O R T O R T O R T O R T O R
RT
CITY OF CHULA VISTA
NAKANO
Project Name: _____________________________________________________
CCV BMP Design Manual
Worksheet B-1 March 2019 Update
Tabular Summary of DMAs Worksheet B-1
DMA Unique
Identifier
Area
(acres)
Impervious
Area
(acres)
% Imp HSG Area Weighted
Runoff
Coefficient
DCV
(Cubic
feet)
Treated by
(BMP ID)
Pollutant
Control Type
Drains to
(POC ID)
Summary of DMA Information (Must match Project description and SWQMP narrative)
No. of DMAs Total DMA
Area
(acres)
Total
Impervious
Area
(acres)
% Impervious Area Weighted
Runoff
Coefficient
DCV
(Cubic
feet)
Total Area
Treated (acres)
No. of
POCs
Where: DMA = Drainage Management Area Imp = Imperviousness ID = identifier
HSG = Hydrologic Soil Group DCV= Design Capture Volume No. = Number
BMP = Best Management Practice POC = Point of Compliance
*Volume Retention for the site as a whole will be met with Biofiltration Basins and Impervious Dispersion.
ATTACHMENT 1C – HARVEST & USE FEASIBILITY
CHECKLIST
ATTACHMENT 1D – INFILTRATION FEASIBILITY LETTER
Note: This attachment includes two infiltration feasibility
letters. The first is formatted for the City of San Diego, and
is included for review by the City of San Diego. The second
is formatted for the City of Chula Vista, and is included for
review by the City of Chula Vista.
City of San Diego Infiltration Feasibility Letter
(For Review by City of San Diego LDR-Engineering and LDR-Geology)
Project No. 07516-42-02
January 9, 2023
Tri Pointe Homes
13520 Evening Creek Drive North, Suite 300
San Diego, California 92128
Attention: Mr. Allen Kashani
Subject: STORMWATER MANAGEMENT RECOMMENDATIONS
NAKANO
SAN DIEGO, CALIFORNIA
Reference: Update Geotechnical Investigation, Nakano Property, Chula Vista, California prepared by
Geocon Incorporated dated September 18, 2020 (Project No. 07516-42-02).
Dear Mr. Kashani:
In response to City of San Diego review comments, we have prepared this report to provide stormwater
management recommendations for the Nakano project. We previously performed an infiltration study
on the property. A summary of our study and stormwater management recommendations are provided
in Appendix C of the referenced report. The report was prepared in accordance with City of Chula Vista
requirements. Provided herein are stormwater recommendations in accordance with the City of San
Diego Stormwater Standards.
Based on the results of our study, full and partial infiltration is considered infeasible due to the presence
undocumented fills, low infiltration characteristics, and existing nearby utilities. Basins should utilize a
liner to prevent infiltration from causing adverse settlement, migrating to adjacent slopes, utilities, and
foundations.
STORM WATER MANAGEMENT
We understand storm water management devices are being proposed in accordance with the current
stormwater standards. If not properly constructed, there is a potential for distress to improvements and
properties located hydrologically down gradient or adjacent to these devices. Factors such as the amount
of water to be detained, its residence time, and soil permeability have an important effect on seepage
transmission and the potential adverse impacts that may occur if the storm water management features
are not properly designed and constructed. We have not performed a hydrogeological study at the site.
If infiltration of storm water runoff occurs, downstream properties and improvements may be subjected
Geocon Project No. 07516-42-02 - 2 - January 9, 2023
to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other
undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table 1 presents the descriptions of the
hydrologic soil groups. In addition, the USDA website also provides an estimated saturated hydraulic
conductivity for the existing soil.
TABLE 1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a
high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately
deep or deep, moderately well drained or well drained soils that have moderately fine texture to
moderately coarse texture. These soils have a moderate rate of water transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
layer that impedes the downward movement of water or soils of moderately fine texture or fine
texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table,
soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly
impervious material. These soils have a very slow rate of water transmission.
The property is underlain by undocumented fill, surficial deposits such as topsoil, colluvium and alluvium,
Terrace Deposits, and the Mission Valley Formation. Table 2 presents the information from the USDA
website for the subject property.
TABLE 2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit
Symbol
Approximate
Percentage
of Property
Hydrologic
Soil Group
Olivenhain cobbly loam, 9 to 30 percent slopes OhE 5.0 D
Riverwash Rm 18.5 D
Salinas clay loam, 0 to 2 percent slopes,
warm MAAT, MLRA 19 SbA 76.6 C
Geocon Project No. 07516-42-02 - 3 - January 9, 2023
Infiltration Testing
We performed two borehole infiltration tests at the locations shown on Figure 1. The tests were
performed in 8-inch-diameter, drilled borings. Table 3 presents the results of the testing. The calculation
sheets are provided herein.
We used the guidelines presented in the Riverside County Low Impact Development BMP Design
Handbook. Based on this widely accepted guideline, the saturated hydraulic conductivity (Ksat) is
equivalent to the infiltration rate. Therefore, the Ksat value determined from our testing is assumed to be
the unfactored infiltration rate.
TABLE 3
UNFACTORED, FIELD-SATURATED, INFILTRATION TEST RESULTS
Test No. Depth (inches) Geologic Unit Field Infiltration
Rate, I (in/hr)
Factored* Field
Infiltration Rate, I
(in/hr)
A-1 68 Qt 0.004 0.002
A-2 92 Qt 0.082 0.041
* Factor of Safety of 2.0 for feasibility determination.
STORM WATER MANAGEMENT CONCLUSIONS
Soil Types
Undocumented Fill (Qpudf) – We encountered undocumented fill up to 18 feet thick at the north end
of the property. The undocumented fill within structural improvement areas will be removed and
replaced with compacted fill. Water that is allowed to migrate into the undocumented fill or compacted
fill will cause settlement. Therefore, full and partial infiltration should be considered infeasible within
fill.
Topsoil (Unmapped) – We encountered topsoil varying between 0.5 and 3 feet thick across the site.
Topsoil within structural improvement areas will be removed and replaced with compacted fill. Water
that is allowed to migrate into the topsoil will cause settlement. Therefore, full and partial infiltration
should be considered infeasible within topsoil.
Colluvium (Qcol) – We encountered colluvium on the north-facing slopes at the south property
boundary, varying between 0.5 and 5 feet thick. Colluvium within structural improvement areas will be
removed and replaced with compacted fill. Water that is allowed to migrate into colluvium will cause
settlement. Therefore, full and partial infiltration should be considered infeasible within areas underlain
by colluvium.
Geocon Project No. 07516-42-02 - 4 - January 9, 2023
Alluvium (Qal) – Alluvium is present in a drainage located at the southeast corner of the property.
Alluvium was also encountered in Trench T-20 beneath undocumented fill at the north end of the site.
Alluvium within structural improvement areas will be removed and replaced with compacted fill. Water
that is allowed to migrate into alluvium will cause settlement. Therefore, full and partial infiltration
should be considered infeasible within areas underlain by alluvium.
Terrace Deposits (Qt) – We encountered Terrace Deposits underlying most of the site below the
artificial fill, topsoil, and alluvium. The Terrace Deposits are comprised of very dense, clayey,
conglomerate. Infiltration into the Terrance Deposits is not feasible due to its low infiltration
characteristics.
Mission Valley Formation (Tmv) – We encountered age Mission Valley in slopes along the southern
portion of the site. Mission Valley Formation may also be present underlying the Terrace Deposits in
the central portion of the site Infiltration into the Mission Valley Formation is not feasible due to low
infiltration characteristics.
Groundwater Elevation
Groundwater was not encountered in our borings or trenches to a depths explored. Infiltration should
not impact groundwater.
Existing Utilities
Existing utilities are located on the north side of the property and along the west and east property
margins. Infiltration near these utilities is considered infeasible. Otherwise, infiltration due to utility
concerns would be feasible.
Soil or Groundwater Contamination
We are unaware of contaminated soil or groundwater on the property. Therefore, full and partial
infiltration associated with this risk is considered feasible.
Slopes
There are no existing slopes that would be impacted by infiltration. There are proposed fill slopes where
infiltration adjacent to the slopes is not feasible.
Infiltration Rates
Our test results indicated slow infiltration rates. The factored rates were 0.002 and 0.082 inches per hour.
The infiltration rates are not high enough to support full or partial infiltration.
Geocon Project No. 07516-42-02 - 5 - January 9, 2023
Storm Water Management Devices
Liners should be incorporated in the proposed basin. The liner should be impermeable (e.g. High-density
polyethylene, HDPE, with a thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC).
Penetration of the liners should be properly sealed. The devices should also be installed in accordance
with the manufacturer’s recommendations. Overflow protection devices should also be incorporated into
the design and construction of the storm water management device.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1) worksheet information to help evaluate the potential for infiltration on the
property. The attached Worksheet C.4-1 presents the completed information for the submittal process.
The regional storm water standards also have a worksheet (Worksheet Form D.5-1) that helps the project
civil engineer estimate the factor of safety based on several factors. Table 4 describes the suitability
assessment input parameters related to the geotechnical engineering aspects for the factor of safety
determination.
TABLE 4
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High
Concern – 3 Points
Medium
Concern – 2 Points
Low
Concern – 1 Point
Assessment Methods
Use of soil survey maps or
simple texture analysis to
estimate short-term
infiltration rates. Use of
well permeameter or
borehole methods without
accompanying continuous
boring log. Relatively
sparse testing with direct
infiltration methods
Use of well permeameter
or borehole methods with
accompanying continuous
boring log. Direct
measurement of
infiltration area with
localized infiltration
measurement methods
(e.g., Infiltrometer).
Moderate spatial
resolution
Direct measurement with
localized (i.e. small-scale)
infiltration testing
methods at relatively high
resolution or use of
extensive test pit
infiltration measurement
methods.
Predominant
Soil Texture
Silty and clayey soils
with significant fines Loamy soils Granular to slightly
loamy soils
Site Soil Variability
Highly variable soils
indicated from site
assessment or unknown
variability
Soil boring/test pits
indicate moderately
homogenous soils
Soil boring/test pits
indicate relatively
homogenous soils
Depth to Groundwater/
Impervious Layer
<5 feet below
facility bottom
5-15 feet below
facility bottom
>15 feet below
facility bottom
Geocon Project No. 07516-42-02 - 6 - January 9, 2023
Table 5 presents the estimated factor values for the evaluation of the factor of safety. This table only
presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer
should evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE 5
FACTOR OF SAFETY WORKSHEET D.5-1 DESIGN VALUES1
Suitability Assessment Factor Category Assigned
Weight (w)
Factor
Value (v)
Product
(p = w x v)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 3 0.75
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/Impervious Layer 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 2.0
1 The project civil engineer should complete Worksheet D.5-1 using the data on this table. Additional information
is required to evaluate the design factor of safety.
CONCLUSIONS
Our results indicate the site has relatively slow infiltration characteristics and should be considered as
having a “no infiltration” condition. Because of the site conditions, it is our opinion that there is a
potential for lateral water migration if infiltration were to be allowed. Undocumented and previously
placed fill exists on the property and has a high potential for adverse settlement when wetted. It is our
opinion that full or partial infiltration is infeasible on this site. Our evaluation included the soil and
geologic conditions, estimated settlement and volume change of the underlying soil, slope stability,
utility considerations, groundwater mounding, retaining walls, foundations and existing groundwater
elevations.
If there are any questions regarding this correspondence, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Rodney C. Mikesell
GE 2533
RCM:arm
(e-mail) Addressee
·········
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?
?
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A
A'
B
B'
C
C'
D
D'
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Qaf
Qaf
Qaf
Qal
Qudf/
Qudf/
Qudf/
T-18
T-19
T-22
T-21
T-20
T-12
T-11
T-23 T-17
T-16
T-14
T-10
T-15
T-13
T-9
T-8
T-4
T-6
T-7
T-5
T-3 T-1
T-2
Qaf
Qaf
(2)
(2)
(2)
(3)(3)
(2)
(2)
(5)
(3)
(2)
(2)
(2)
(2)
(2)
10-15°
(3)(2)
(2)
(+18)
(5)
(5)
(9)
(2)
(2)
@7' =
@15' =
@24' =
@29' =
@36' =
@58' =
16°
65°
21°
20°
11°
LD-1
A-2
A-1
(6)
?
?
??
?
?
?
?
APPROX. LIMITS OF
DISTURBANCE/REMEDIAL
GRADING
Qaf
Tsdcg
LD-2
T-24
Tsdcg
Tsdcg 29°@19' =
@30' =
@33' =
@39' =
@59' =
@61' =
@65' =
11°
14°
16°
0-14°
10°
13°
Tmv
Tmv
Tmv
Tmv
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:02/10/2022 7:48AM | By:ALVIN LADRILLONO | File Location:W:\1_GEOTECH\07000\07500\07516-42-02\2022-02-09\07516-42-02 Geo Map.30.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC 1AP
NAKANO
CHULA VISTA, CALIFORNIA
60'02 - 09 - 2022
07516 - 42 - 02
1 1 1
........UNDOCUMENTED FILL
........ARTIFICIAL FILL
........ALLUVIUM
........TERRACE DEPOSITS
(Dotted Where Buried)
........SAN DIEGO FORMATION (Conglomerate)
........MISSION VALLEY FORMATION
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........APPROX. LOCATION OF BORING
........APPROX. LOCATION OF TRENCH
........APPROX. LOCATION OF INFILTRATION TEST
........APPROX. DEPTH OF REMEDIAL GRADING (In Feet, MSL)
........APPROX. LOCATIION OF GEOLOGIC CROSS SECTION
LD-2
D D'
GEOCON LEGEND
?
Qudf
Qaf
Qal
Qt
Tmv
(5)
A-2
Tsdcg
T-24
Aardvark Permeameter Data Analysis
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:
Borehole Diameter, d (in.):8.00 Ref. EL (feet, MSL):102.0
Borehole Depth, H (in):68.00 Bottom EL (feet, MSL):96.3
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):84.75
Head Height Measured, h (in.):5.50
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.530 319.29 63.858
3 5.00 1.665 46.11 9.222
4 5.00 0.155 4.29 0.858
5 5.00 0.045 1.25 0.249
6 5.00 0.045 1.25 0.249
7 5.00 0.035 0.97 0.194
8 5.00 0.035 0.97 0.194
9 10.00 0.045 1.25 0.125
10 10.00 0.045 1.25 0.125
11 10.00 0.030 0.83 0.083
12 10.00 0.025 0.69 0.069
13 10.00 0.020 0.55 0.055
14 10.00 0.015 0.42 0.042
15 10.00 0.015 0.42 0.042
Steady Flow Rate, Q (in3/min):0.046
Soil Matric Flux Potential, Φm
Φm=0.00060 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =6.07E‐05 in/min 0.004 in/hr
Nakano
07516‐42‐02
A‐1
0.0
0.5
1.0
0 1020304050607080
Q
(
i
n
3/m
i
n
)
Time (min)
Borehole Infiltration Test
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:Ref. EL (feet, MSL):100.0
Bottom EL (feet, MSL):92.3
Borehole Diameter, d (in.):8.00
Borehole Depth, H (in):92.00
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):108.75
Head Height Measured, h (in.):4.75
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.255 311.68 62.335
3 5.00 1.095 30.32 6.065
4 5.00 0.315 8.72 1.745
5 5.00 0.995 27.55 5.511
6 5.00 1.075 29.77 5.954
7 5.00 0.985 27.28 5.455
8 5.00 0.915 25.34 5.068
9 5.00 0.890 24.65 4.929
10 5.00 0.845 23.40 4.680
11 5.00 0.770 21.32 4.265
12 5.00 0.740 20.49 4.098
13 5.00 0.695 19.25 3.849
14 5.00 0.665 18.42 3.683
15 5.00 0.655 18.14 3.628
16 6.00 0.750 20.77 3.462
17 4.00 0.440 12.18 3.046
18 5.00 0.565 15.65 3.129
19 5.00 0.535 14.82 2.963
20 5.00 0.530 14.68 2.935
21 5.00 0.510 14.12 2.825
22 6.00 0.610 16.89 2.815
23 4.00 0.405 11.22 2.804
Steady Flow Rate, Q (in3/min):2.815
Soil Matric Flux Potential, Φm
Φm=0.0538 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =1.37E‐03 in/min 0.082 in/hr
Nakano
07516‐42‐02
A‐2
0.0
5.0
10.0
0 102030405060708090100
Q
(
i
n
3/m
i
n
)
Time (min)
Appendix C: Geotechnical and Groundwater Investigation Requirements
Worksheet C.4-1: Categorization of Infiltration Feasibility Condition Based on Geotechnical Conditions9
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
Part 1 - Full Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Entire Site Design
Criteria 1: Infiltration Rate Screening
1A
Is the mapped hydrologic soil group according to the NRCS Web Soil Survey or UC Davis
Soil Web Mapper Type A or B and corroborated by available site soil data11?
☐ Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result
or continue to Step 1B if the applicant elects to perform infiltration testing.
☐No; the mapped soil types are A or B but is not corroborated by available site soil data
(continue to Step 1B).
☒No; the mapped soil types are C, D, or “urban/unclassified” and is corroborated by
available site soil data. Answer “No” to Criteria 1 Result.
☐No; the mapped soil types are C, D, or “urban/unclassified” but is not corroborated by
available site soil data (continue to Step 1B).
1B
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1?
☐Yes; Continue to Step 1C.
☐No; Skip to Step 1D.
1C
Is the reliable infiltration rate calculated using planning phase methods from Table D.3-1
greater than 0.5 inches per hour?
☐Yes; the DMA may feasibly support full infiltration. Answer “Yes” to Criteria 1 Result.
☐No; full infiltration is not required. Answer “No” to Criteria 1 Result.
1D
Infiltration Testing Method. Is the selected infiltration testing method suitable during the
design phase (see Appendix D.3)? Note: Alternative testing standards may be allowed with
appropriate rationales and documentation.
☐Yes; continue to Step 1E.
☐No; select an appropriate infiltration testing method.
9 Note that it is not required to investigate each and every criterion in the worksheet, a single “no”
answer in Part 1, Part 2, Part 3, or Part 4 determines a full, partial, or no infiltration condition.
10 This form must be completed each time there is a change to the site layout that would affect the
infiltration feasibility condition. Previously completed forms shall be retained to document the
evolution of the site stormwater design.
11 Available data includes site-specific sampling or observation of soil types or texture classes, such as
obtained from borings or test pits necessary to support other design elements.
C-16 The City of San Diego | Stormwater Standards | May 2021 Edition Part
1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
1E
Number of Percolation/Infiltration Tests. Does the infiltration testing method performed
satisfy the minimum number of tests specified in Table D.3-2?
☐Yes; continue to Step 1F.
☐No; conduct appropriate number of tests.
IF
Factor of Safety. Is the suitable Factor of Safety selected for full infiltration design? See
guidance in D.5; Tables D.5-1 and D.5-2; and Worksheet D.5-1 (Form I-9).
☐Yes; continue to Step 1G.
☐No; select appropriate factor of safety.
1G
Full Infiltration Feasibility. Is the average measured infiltration rate divided by the Factor
of Safety greater than 0.5 inches per hour?
☐Yes; answer “Yes” to Criteria 1 Result.
☐No; answer “No” to Criteria 1 Result.
Criteria 1
Result
Is the estimated reliable infiltration rate greater than 0.5 inches per hour within the DMA
where runoff can reasonably be routed to a BMP?
☐Yes; the DMA may feasibly support full infiltration. Continue to Criteria 2.
☒No; full infiltration is not required. Skip to Part 1 Result.
We performed two borehole infiltration tests in the area of the proposed basin. The test results are
summarized below. The rates are not high enough to support full or partial infiltration.
A-1: 0.004 in/hr (0.002 in/hr using a factor of 2 for feasibility determination)
A-2: 0.082 in/hr (0.041 in/hr using a factor of 2 for feasibility determination)
C-17 The City of San Diego | Stormwater Standards | May 2021 Edition Part
1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
Criteria 2: Geologic/Geotechnical Screening
2A
If all questions in Step 2A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 2A answer “No” to Criteria 2, and submit an “Infiltration
Feasibility Condition Letter” that meets the requirements in Appendix C.1.1. The
geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because one
of the following setbacks cannot be avoided and therefore result in the DMA being in a no
infiltration condition. The setbacks must be the closest horizontal radial distance from the
surface edge (at the overflow elevation) of the BMP.
2A-1 Can the proposed full infiltration BMP(s) avoid areas with existing fill
materials greater than 5 feet thick below the infiltrating surface? ☐Yes ☐No
2A-2 Can the proposed full infiltration BMP(s) avoid placement within 10
feet of existing underground utilities, structures, or retaining walls? ☐Yes ☐No
2A-3
Can the proposed full infiltration BMP(s) avoid placement within 50
feet of a natural slope (>25%) or within a distance of 1.5H from fill
slopes where H is the height of the fill slope?
☐Yes ☐No
2B
When full infiltration is determined to be feasible, a geotechnical investigation report must
be prepared that considers the relevant factors identified in Appendix C.2.1.
If all questions in Step 2B are answered “Yes,” then answer “Yes” to Criteria 2 Result.
If there are “No” answers continue to Step 2C.
2B-1
Hydroconsolidation. Analyze hydroconsolidation potential per
approved ASTM standard due to a proposed full infiltration BMP.
Can full infiltration BMPs be proposed within the DMA without
increasing hydroconsolidation risks?
☐Yes ☐No
2B-2
Expansive Soils. Identify expansive soils (soils with an expansion index
greater than 20) and the extent of such soils due to proposed full
infiltration BMPs.
Can full infiltration BMPs be proposed within the DMA without
increasing expansive soil risks?
☐Yes ☐No
C-18 The City of San Diego | Stormwater Standards | May 2021 Edition
Part 1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
2B-3
Liquefaction. If applicable, identify mapped liquefaction areas.
Evaluate liquefaction hazards in accordance with Section 6.4.2 of the
City of San Diego's Guidelines for Geotechnical Reports (2011 or most
recent edition). Liquefaction hazard assessment shall take into
account any increase in groundwater elevation or groundwater mounding
that could occur as a result of proposed infiltration or percolation
facilities.
Can full infiltration BMPs be proposed within the DMA without
increasing liquefaction risks?
☐Yes ☐No
2B-4
Slope Stability. If applicable, perform a slope stability analysis in
accordance with the ASCE and Southern California Earthquake Center
(2002) Recommended Procedures for Implementation of DMG Special
Publication 117, Guidelines for Analyzing and Mitigating Landslide
Hazards in California to determine minimum slope setbacks for full
infiltration BMPs. See the City of San Diego's Guidelines for
Geotechnical Reports (2011) to determine which type of slope stability
analysis is required.
Can full infiltration BMPs be proposed within the DMA without
increasing slope stability risks?
☐Yes ☐No
2B-5
Other Geotechnical Hazards. Identify site-specific geotechnical
hazards not already mentioned (refer to Appendix C.2.1).
Can full infiltration BMPs be proposed within the DMA without
increasing risk of geologic or geotechnical hazards not already
mentioned?
☐Yes ☐No
2B-6
Setbacks. Establish setbacks from underground utilities, structures,
and/or retaining walls. Reference applicable ASTM or other recognized
standard in the geotechnical report.
Can full infiltration BMPs be proposed within the DMA using
established setbacks from underground utilities, structures, and/or
retaining walls?
☐Yes ☐No
C-19 The City of San Diego | Stormwater Standards | May 2021 Edition Part
1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
2C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 2B. Provide a
discussion of geologic/geotechnical hazards that would prevent full
infiltration BMPs that cannot be reasonably mitigated in the
geotechnical report. See Appendix C.2.1.8 for a list of typically
reasonable and typically unreasonable mitigation measures.
Can mitigation measures be proposed to allow for full infiltration
BMPs? If the question in Step 2 is answered “Yes,” then answer “Yes”
to Criteria 2 Result.
If the question in Step 2C is answered “No,” then answer “No” to
Criteria 2 Result.
☐Yes ☐No
Criteria 2
Result
Can infiltration greater than 0.5 inches per hour be allowed without
increasing risk of geologic or geotechnical hazards that cannot be
reasonably mitigated to an acceptable level?
☐Yes ☐No
Summarize findings and basis; provide references to related reports or exhibits.
Part 1 Result – Full Infiltration Geotechnical Screening 12 Result
If answers to both Criteria 1 and Criteria 2 are “Yes”, a full infiltration
design is potentially feasible based on Geotechnical conditions only.
If either answer to Criteria 1 or Criteria 2 is “No”, a full infiltration
design is not required.
☐Full infiltration Condition
☒Complete Part 2
12 To be completed using gathered site information and best professional judgement considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
C-20 The City of San Diego | Stormwater Standards | May 2021 Edition
Part 1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
Part 2 – Partial vs. No Infiltration Feasibility Screening Criteria
DMA(s) Being Analyzed: Project Phase:
Entire Site Design
Criteria 3 : Infiltration Rate Screening
3A
NRCS Type C, D, or “urban/unclassified”: Is the mapped hydrologic soil group according
to the NRCS Web Soil Survey or UC Davis Soil Web Mapper is Type C, D, or
“urban/unclassified” and corroborated by available site soil data?
☐Yes; the site is mapped as C soils and a reliable infiltration rate of 0.15 in/hr. is used to
size partial infiltration BMPS. Answer “Yes” to Criteria 3 Result.
☐Yes; the site is mapped as D soils or “urban/unclassified” and a reliable infiltration
rate of 0.05 in/hr. is used to size partial infiltration BMPS. Answer “Yes” to Criteria 3
Result.
☒No; infiltration testing is conducted (refer to Table D.3-1), continue to Step 3B.
3B
Infiltration Testing Result: Is the reliable infiltration rate (i.e. average measured
infiltration rate/2) greater than 0.05 in/hr. and less than or equal to 0.5 in/hr?
☐Yes; the site may support partial infiltration. Answer “Yes” to Criteria 3 Result.
☒No; the reliable infiltration rate (i.e. average measured rate/2) is less than 0.05 in/hr.,
partial infiltration is not required. Answer “No” to Criteria 3 Result.
Criteria 3
Result
Is the estimated reliable infiltration rate (i.e., average measured infiltration rate/2) greater than
or equal to 0.05 inches/hour and less than or equal to 0.5 inches/hour at any location within
each DMA where runoff can reasonably be routed to a BMP?
☐Yes; Continue to Criteria 4.
☒No: Skip to Part 2 Result.
We performed two borehole infiltration tests in the area of the proposed basin. The test results
are summarized below. The rates are not high enough to support full or partial infiltration.
A-1: 0.004 in/hr (0.002 in/hr using a factor of 2 for feasibility determination)
A-2: 0.082 in/hr (0.041 in/hr using a factor of 2 for feasibility determination)
C-21 The City of San Diego | Stormwater Standards | May 2021 Edition
Part 1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
Criteria 4: Geologic/Geotechnical Screening
4A
If all questions in Step 4A are answered “Yes,” continue to Step 2B.
For any “No” answer in Step 4A answer “No” to Criteria 4 Result, and submit an “Infiltration
Feasibility Condition Letter” that meets the requirements in Appendix C.1.1. The
geologic/geotechnical analyses listed in Appendix C.2.1 do not apply to the DMA because
one of the following setbacks cannot be avoided and therefore result in the DMA being in a
no infiltration condition. The setbacks must be the closest horizontal radial distance from the
surface edge (at the overflow elevation) of the BMP.
4A-1 Can the proposed partial infiltration BMP(s) avoid areas with existing
fill materials greater than 5 feet thick? ☐Yes ☐No
4A-2
Can the proposed partial infiltration BMP(s) avoid placement within
10 feet of existing underground utilities, structures, or retaining walls?☐Yes ☐No
4A-3
Can the proposed partial infiltration BMP(s) avoid placement within 50
feet of a natural slope (>25%) or within a distance of 1.5H from fill
slopes where H is the height of the fill slope?
☐Yes ☐No
4B
When full infiltration is determined to be feasible, a geotechnical investigation report must
be prepared that considers the relevant factors identified in Appendix C.2.1
If all questions in Step 4B are answered “Yes,” then answer “Yes” to Criteria 4 Result.
If there are any “No” answers continue to Step 4C.
4B-1
Hydroconsolidation. Analyze hydroconsolidation potential per
approved ASTM standard due to a proposed full infiltration BMP.
Can partial infiltration BMPs be proposed within the DMA without
increasing hydroconsolidation risks?
☐Yes ☐No
4B-2
Expansive Soils. Identify expansive soils (soils with an expansion
index greater than 20) and the extent of such soils due to proposed full
infiltration BMPs.
Can partial infiltration BMPs be proposed within the DMA without
increasing expansive soil risks?
☐Yes ☐No
4B-3
Liquefaction. If applicable, identify mapped liquefaction areas.
Evaluate liquefaction hazards in accordance with Section 6.4.2 of the
City of San Diego's Guidelines for Geotechnical Reports (2011).
Liquefaction hazard assessment shall take into account any increase in
groundwater elevation or groundwater mounding that could occur as a
result of proposed infiltration or percolation facilities.
Can partial infiltration BMPs be proposed within the DMA without
increasing liquefaction risks?
☐Yes ☐No
C-22 The City of San Diego | Stormwater Standards | May 2021 Edition Part
1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
4B-4
Slope Stability. If applicable, perform a slope stability analysis in
accordance with the ASCE and Southern California Earthquake Center
(2002) Recommended Procedures for Implementation of
DMG Special Publication 117, Guidelines for Analyzing and
Mitigating Landslide Hazards in California to determine minimum
slope setbacks for full infiltration BMPs. See the City of San Diego's
Guidelines for Geotechnical Reports (2011) to determine which type
of slope stability analysis is required.
Can partial infiltration BMPs be proposed within the DMA without
increasing slope stability risks?
☐Yes ☐No
4B-5
Other Geotechnical Hazards. Identify site-specific geotechnical
hazards not already mentioned (refer to Appendix C.2.1).
Can partial infiltration BMPs be proposed within the DMA without
increasing risk of geologic or geotechnical hazards not already
mentioned?
☐Yes ☐No
4B-6
Setbacks. Establish setbacks from underground utilities, structures,
and/or retaining walls. Reference applicable ASTM or other
recognized standard in the geotechnical report.
Can partial infiltration BMPs be proposed within the DMA using
recommended setbacks from underground utilities, structures,
and/or retaining walls?
☐Yes ☐No
4C
Mitigation Measures. Propose mitigation measures for each
geologic/geotechnical hazard identified in Step 4B. Provide a
discussion on geologic/geotechnical hazards that would prevent partial
infiltration BMPs that cannot be reasonably mitigated in the
geotechnical report. See Appendix C.2.1.8 for a list of typically
reasonable and typically unreasonable mitigation measures.
Can mitigation measures be proposed to allow for partial infiltration
BMPs? If the question in Step 4C is answered “Yes,” then answer
“Yes” to Criteria 4 Result.
If the question in Step 4C is answered “No,” then answer “No” to
Criteria 4 Result.
☐Yes ☐No
Criteria
4 Result
Can infiltration of greater than or equal to 0.05 inches/hour and less
than or equal to 0.5 inches/hour be allowed without increasing the risk
of geologic or geotechnical hazards that cannot be reasonably mitigated
to an acceptable level?
☐Yes ☐No
C-23 The City of San Diego | Stormwater Standards | May 2021 Edition Part
1: BMP Design Manual
Appendix C: Geotechnical and Groundwater Investigation Requirements
Categorization of Infiltration Feasibility Condition based on
Geotechnical Conditions
Worksheet C.4-1: Form I-
8A10
Summarize findings and basis; provide references to related reports or exhibits.
Part 2 – Partial Infiltration Geotechnical Screening Result13 Result
If answers to both Criteria 3 and Criteria 4 are “Yes”, a partial infiltration
design is potentially feasible based on geotechnical conditions only.
If answers to either Criteria 3 or Criteria 4 is “No”, then infiltration of any volume
is considered to be infeasible within the site.
☐ Partial Infiltration
Condition
☒ No Infiltration
Condition
13 To be completed using gathered site information and best professional judgement considering the definition of MEP in
the MS4 Permit. Additional testing and/or studies may be required by City Engineer to substantiate findings.
C-24 The City of San Diego | Stormwater Standards | May 2021 Edition
Part 1: BMP Design Manual
City of Chula Vista Infiltration Feasibility Letter
(For Review by City of Chula Vista)
Project No. 07516-42-02 -C-1 - September 18, 2020
APPENDIX C
STORM WATER MANAGEMENT
We understand storm water management devices are being proposed in accordance with the current
Storm Water Standards (SWS). If not properly constructed, there is a potential for distress to
improvements and properties located hydrologically down gradient or adjacent to these devices.
Factors such as the amount of water to be detained, its residence time, and soil permeability have an
important effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed. We have not performed a
hydrogeological study at the site. If infiltration of storm water runoff occurs, downstream properties
and improvements may be subjected to seeps, springs, slope instability, raised groundwater, movement
of foundations and slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the descriptions of
the hydrologic soil groups. In addition, the USDA website also provides an estimated saturated
hydraulic conductivity for the existing soil.
TABLE C-1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a
high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of
moderately deep or deep, moderately well drained or well drained soils that have moderately
fine texture to moderately coarse texture. These soils have a moderate rate of water
transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
layer that impedes the downward movement of water or soils of moderately fine texture or fine
texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table,
soils that have a claypan or clay layer at or near the surface, and soils that are shallow over
nearly impervious material. These soils have a very slow rate of water transmission.
Project No. 07516-42-02 -C-2 - September 18, 2020
The property is underlain by undocumented fill, surficial deposits such as topsoil, colluvium and
alluvium, Terrace Deposits, and the Mission Valley Formation. Table C-2 presents the information from
the USDA website for the subject property.
TABLE C-2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit
Symbol
Approximate
Percentage
of Property
Hydrologic
Soil Group
Olivenhain cobbly loam, 9 to 30 percent slopes OhE 5.0 D
Riverwash Rm 18.5 D
Salinas clay loam, 0 to 2 percent slopes,
warm MAAT, MLRA 19 SbA 76.6 C
Infiltration Testing
We performed two borehole infiltration tests at the locations shown on Figure 2. The tests were
performed in 8-inch-diameter, drilled borings. Table C-3 presents the results of the testing. The
calculation sheets are provided herein.
We used the guidelines presented in the Riverside County Low Impact Development BMP Design
Handbook. Based on this widely accepted guideline, the saturated hydraulic conductivity (Ksat) is
equivalent to the infiltration rate. Therefore, the Ksat value determined from our testing is assumed to
be the unfactored infiltration rate.
TABLE C-3
UNFACTORED, FIELD-SATURATED, INFILTRATION TEST RESULTS
Test No. Depth (inches) Geologic Unit Field Infiltration
Rate, I (in/hr)
Factored* Field
Infiltration Rate, I (in/hr)
A-1 68 Qudf 0.004 0.002
A-2 92 Qudf 0.244 0.12
* Factor of Safety of 2.0 for feasibility determination.
STORM WATER MANAGEMENT CONCLUSIONS
Soil Types
Undocumented Fill (Qpudf) – We encountered undocumented fill up to 18 feet thick at the north end
of the property. The undocumented fill within structural improvement areas will be removed and
replaced with compacted fill. Water that is allowed to migrate into the undocumented fill or
Project No. 07516-42-02 -C-3 - September 18, 2020
compacted fill will cause settlement. Therefore, full and partial infiltration should be considered
infeasible within fill.
Topsoil (Unmapped) – We encountered topsoil varying between 0.5 and 3 feet thick across the site.
Topsoil within structural improvement areas will be removed and replaced with compacted fill. Water
that is allowed to migrate into the topsoil will cause settlement. Therefore, full and partial infiltration
should be considered infeasible within topsoil.
Colluvium (Qcol) – We encountered colluvium on the north-facing slopes at the south property
boundary, varying between 0.5 and 5 feet thick. Colluvium within structural improvement areas will
be removed and replaced with compacted fill. Water that is allowed to migrate into colluvium will
cause settlement. Therefore, full and partial infiltration should be considered infeasible within areas
underlain by colluvium.
Alluvium (Qal) – Alluvium is present in a drainage located at the southeast corner of the property.
Alluvium was also encountered in Trench T-20 beneath undocumented fill at the north end of the site.
Alluvium within structural improvement areas will be removed and replaced with compacted fill.
Water that is allowed to migrate into alluvium will cause settlement. Therefore, full and partial
infiltration should be considered infeasible within areas underlain by alluvium.
Terrace Deposits (Qt) – We encountered Terrace Deposits underlying most of the site below the
artificial fill, topsoil, and alluvium. Infiltration into Terrace Deposits may be possible.
Mission Valley Formation (Tmv) – We encountered age Mission Valley in slopes along the southern
portion of the site. Mission Valley Formation may also be present underlying the Terrace Deposits in
the central portion of the site Infiltration into the Mission Valley Formation is not feasible due to low
infiltration characteristics.
Groundwater Elevation
Groundwater was not encountered in our borings or trenches to a depths explored. Infiltration should
not impact groundwater.
Existing Utilities
Existing utilities are located on the north side of the property and along the west and east property
margins. Infiltration near these utilities is considered infeasible. Otherwise, infiltration due to utility
concerns would be feasible.
Project No. 07516-42-02 -C-4 - September 18, 2020
Soil or Groundwater Contamination
We are unaware of contaminated soil or groundwater on the property. Therefore, full and partial
infiltration associated with this risk is considered feasible.
Slopes
There are no existing slopes that would be impacted by infiltration. There are proposed fill slopes
where infiltration adjacent to the slopes is not feasible.
Infiltration Rates
Our test results indicated slow infiltration rates. The factored rates were 0.002 and 0.12 inches per
hour. The infiltration rates are not high enough to support full or partial infiltration in the area of the
proposed BMP.
Storm Water Management Devices
Liners should be incorporated in the proposed basin. The liner should be impermeable (e.g. High-
density polyethylene, HDPE, with a thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC).
Penetration of the liners should be properly sealed. The devices should also be installed in accordance
with the manufacturer’s recommendations. Overflow protection devices should also be incorporated
into the design and construction of the storm water management device.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1) worksheet information to help evaluate the potential for infiltration on
the property. The attached Worksheet C.4-1 presents the completed information for the submittal
process.
The regional storm water standards also have a worksheet (Worksheet Form D.5-1) that helps the
project civil engineer estimate the factor of safety based on several factors. Table C-4 describes the
suitability assessment input parameters related to the geotechnical engineering aspects for the factor of
safety determination.
Project No. 07516-42-02 -C-5 - September 18, 2020
TABLE C-4
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High
Concern – 3 Points
Medium
Concern – 2 Points
Low
Concern – 1 Point
Assessment Methods
Use of soil survey maps or
simple texture analysis to
estimate short-term
infiltration rates. Use of
well permeameter or
borehole methods without
accompanying continuous
boring log. Relatively
sparse testing with direct
infiltration methods
Use of well permeameter
or borehole methods with
accompanying continuous
boring log. Direct
measurement of
infiltration area with
localized infiltration
measurement methods
(e.g., Infiltrometer).
Moderate spatial
resolution
Direct measurement with
localized (i.e. small-scale)
infiltration testing
methods at relatively high
resolution or use of
extensive test pit
infiltration measurement
methods.
Predominant
Soil Texture
Silty and clayey soils
with significant fines Loamy soils Granular to slightly
loamy soils
Site Soil Variability
Highly variable soils
indicated from site
assessment or unknown
variability
Soil boring/test pits
indicate moderately
homogenous soils
Soil boring/test pits
indicate relatively
homogenous soils
Depth to Groundwater/
Impervious Layer
<5 feet below
facility bottom
5-15 feet below
facility bottom
>15 feet below
facility bottom
Table C-5 presents the estimated factor values for the evaluation of the factor of safety. This table only
presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer
should evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE C-5
FACTOR OF SAFETY WORKSHEET D.5-1 DESIGN VALUES1
Suitability Assessment Factor Category Assigned
Weight (w)
Factor
Value (v)
Product
(p = w x v)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 3 0.75
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/Impervious Layer 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 2.0
1 The project civil engineer should complete Worksheet D.5-1 using the data on this table. Additional
information is required to evaluate the design factor of safety.
Project No. 07516-42-02 -C-6 - September 18, 2020
CONCLUSIONS
Our results indicate the site has relatively slow infiltration characteristics. Because of the site
conditions, it is our opinion that there is a potential for lateral water migration. Undocumented and
previously placed fill exists on the property and has a high potential for adverse settlement when
wetted. It is our opinion that full or partial infiltration is infeasible on this site. Our evaluation included
the soil and geologic conditions, estimated settlement and volume change of the underlying soil, slope
stability, utility considerations, groundwater mounding, retaining walls, foundations and existing
groundwater elevations.
Aardvark Permeameter Data Analysis
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:
Borehole Diameter, d (in.):8.00 Ref. EL (feet, MSL):102.0
Borehole Depth, H (in):68.00 Bottom EL (feet, MSL):96.3
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):84.75
Head Height Measured, h (in.):5.50
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.530 319.29 63.858
3 5.00 1.665 46.11 9.222
4 5.00 0.155 4.29 0.858
5 5.00 0.045 1.25 0.249
6 5.00 0.045 1.25 0.249
7 5.00 0.035 0.97 0.194
8 5.00 0.035 0.97 0.194
9 10.00 0.045 1.25 0.125
10 10.00 0.045 1.25 0.125
11 10.00 0.030 0.83 0.083
12 10.00 0.025 0.69 0.069
13 10.00 0.020 0.55 0.055
14 10.00 0.015 0.42 0.042
15 10.00 0.015 0.42 0.042
Steady Flow Rate, Q (in3/min):0.046
Soil Matric Flux Potential, Φm
Φm=0.00060 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =6.07E‐05 in/min 0.004 in/hr
Nakano
07516‐42‐02
A‐1
0.0
0.5
1.0
0 1020304050607080
Q
(
i
n
3/m
i
n
)
Time (min)
Borehole Infiltration Test
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:Ref. EL (feet, MSL):100.0
Bottom EL (feet, MSL):92.3
Borehole Diameter, d (in.):8.00
Borehole Depth, H (in):92.00
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):108.75
Head Height Measured, h (in.):4.75
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.255 311.68 62.335
3 5.00 1.095 30.32 6.065
4 5.00 0.315 8.72 1.745
5 5.00 0.995 27.55 5.511
6 5.00 1.075 29.77 5.954
7 5.00 0.985 27.28 5.455
8 5.00 0.915 25.34 5.068
9 5.00 0.890 24.65 4.929
10 5.00 0.845 23.40 4.680
11 5.00 0.770 21.32 4.265
12 5.00 0.740 20.49 4.098
13 5.00 0.695 19.25 3.849
14 5.00 0.665 18.42 3.683
15 5.00 0.655 18.14 3.628
16 6.00 0.750 20.77 3.462
17 4.00 0.440 12.18 3.046
18 5.00 0.565 15.65 3.129
19 5.00 0.535 14.82 2.963
20 5.00 0.530 14.68 2.935
21 5.00 0.510 14.12 2.825
22 6.00 0.610 16.89 2.815
23 4.00 0.405 11.22 2.804
Steady Flow Rate, Q (in3/min):2.815
Soil Matric Flux Potential, Φm
Φm=0.0538 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =1.37E‐03 in/min 0.082 in/hr
Nakano
07516‐42‐02
A‐2
0.0
5.0
10.0
0 102030405060708090100
Q
(
i
n
3/m
i
n
)
Time (min)
ATTACHMENT 1E – POLLUTANT CONTROL BMP DESIGN
WORKSHEETS/CALCULATIONS
ATTACHMENT 1B: Worksheet B.2-1: DCV
85th percentile 24-hr storm depth from Figure B.1.=0.515 in
DMA ID BMP ID
BMP Drainage
Area (ac)
BMP Drainage
Area (SF)
Impervious
Area (ac)
Amended
Soils (ac)
(C=0.1)
Natural A
Soils (ac)
(C=0.1)
Natural B
Soils (ac)
(C=0.14)
Natural C
Soils (ac)
(C=0.23)
Natural D
Soils (ac)
(C=0.3)
%
Impervious Composite C
1
Tree Credit
Volume (cf)
Rain Barrels
Credit
Volume (cf)
Design
Capture
Volume
(DCV) (CF)
Project Site 1,2,3 20.3 884339 13.08 4.47 2.75 0 64.4%0.633 24027
Notes:
1) Equation for composite C factor = (0.9*Impervious Area +C*Pervious Area)/Total Area per BMP Design Manual.
C factors are from Table B.1-1 of August 2021 City BMP Design Manual.
2) Volume Retention will be met with Biofiltration Basins and Impervious Dispersion.
Project Name
BMP ID
1 884339 sq. ft.
2 0.633078818
3 0.515 inches
4 24027 cu. ft.
5 0 in/hr.
6 2
7 0 in/hr.
10 553 cu. ft.
Target volume retention [Line 9 x Line 4]
Nakano
Site
%When Line 7 > 0.01 in/hr. = Minimum (40, 166.9 x Line 7 +6.62)
When Line 7 ≤ 0.01 in/hr. = 3.5%
9
Fraction of DCV to be retained (Figure B.5-3)
0.023
When Line 8 > 8% =
0.0000013 x Line 8 3 - 0.000057 x Line 8 2 + 0.0086 x Line 8 - 0.014
When Line 8 ≤ 8% = 0.023
Factor of safety
Reliable infiltration rate, for biofiltration BMP sizing [Line 5 / Line 6]
Sizing Method for Volume Retention
Criteria Worksheet B.5-2
Area draining to the BMP
Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)
85th percentile 24-hour rainfall depth
8
Average annual volume reduction target (Figure B.5-2)
3.5
Design capture volume [Line 1 x Line 2 x (Line 3/12)]
Volume Retention Requirement
Measured infiltration rate in the DMA
Note:
When mapped hydrologic soil groups are used enter 0.10 for NRCS Type D soils
and for NRCS Type C soils enter 0.30
When in no infiltration condition and the actual measured infiltration rate is
unknown enter 0.0 if there are geotechnical and/or groundwater hazards identified
in Appendix C or enter 0.05
Project Name
BMP ID
1 sq. ft.
2
3 sq. ft.
4 sq. ft.
5 sq. ft.
Identification 1 4 5
6 11469
7 13651
10 sq. ft.
11 sq. ft.
12
13
14 cu. ft.
15 cu. ft.
Identification
1 cu. ft.
2 cu. ft.
3 cu. ft.
4 cu. ft.
5 cu. ft.
cu. ft.
17
16
Sum of volume retention benefits from other site design BMPs (e.g. trees; rain
barrels etc.). [sum of Line 16 Credits for Id’s 1 to 5]
Provide documentation of how the site design credit is calculated in the PDP
SWQMP.
0
-16.57874435
Target Volume Retention [Line 10 from Worksheet B.5.2] 553
Volume retention required from other site design BMPs
[(1-Line 13) x Line 14]
Nakano
Site
0.00 0.00
9
Effective Credit Area
9101 0 0
[Line 7/Line 6]
0
Impervious area draining to the landscape area
(sq. ft.)
8
Impervious to Pervious Area ratio
1.19 0.00 0.00
Landscape Area (must be identified on DS-3247)
2 3
Landscape area that meet the requirements in
SD-B and SD-F Fact Sheet (sq. ft.)
Area draining to the biofiltration BMP 884339
Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)0.63307882
Volume Retention for No Infiltration Condition Worksheet B.5-6
Is Line 16 ≥ Line 15?Volume Retention Performance Standard is Met
0
If (Line 8 >1.5, Line 6, Line 7/1.5]
Sum of Landscape area [sum of Line 9 Id’s 1 to 5]9101
Provided footprint for evapotranspiration [Line 5 + Line 10]17232
Volume Retention Performance Standard
Is Line 11 ≥ Line 4?Volume Retention Performance Standard is Met
Site Design Type Credit
Site Design BMP
Fraction of the performance standard met through the BMP footprint and/or
landscaping [Line 11/Line 4]1.03
Effective impervious area draining to the BMP [Line 1 x Line 2]559856
Required area for Evapotranspiration [Line 3 x 0.03]16796
Biofiltration BMP Footprint 8131
ATTACHMENT 1B: Worksheet B.2-1: DCV
85th percentile 24-hr storm depth from Figure B.1.= 0.515 in
DMA ID BMP ID
BMP Drainage
Area (ac)
BMP Drainage
Area (SF)
Impervious
Area (ac)
Amended
Soils (ac)
(C=0.1)
Natural A
Soils (ac)
(C=0.1)
Natural B
Soils (ac)
(C=0.14)
Natural C
Soils (ac)
(C=0.23)
Natural D
Soils (ac)
(C=0.3)
%
Impervious Composite C1
Tree Credit
Volume (cf)
Rain Barrels
Credit
Volume (cf)
Design
Capture
Volume
(DCV) (CF)
1 1 2.49 108312 1.77 0.72 0 71.1% 0.669 3108
Notes:
1) Equation for composite C factor = (0.9*Impervious Area +C*Pervious Area)/Total Area per BMP Design Manual.
C factors are from Table B.1-1 of August 2021 City BMP Design Manual.
CALCULATION FOR MEDIA FILTRATION RATE WHEN CONTROLLED BY UNDERDRAIN ORIFICE
Surface ponding [6 inch minimum, 12 inch maximum]6
Media thickness [18 inches minimum], also add mulch layer and
washed ASTM 33 fine aggregate sand thickness to this line for
sizing calculations 24
Aggregate storage (also add ASTM No 8 stone) above underdrain
invert (12 inches typical) – use 0 inches if the aggregate is not over
the entire bottom surface area 12
Diameter of underdrain orifice 1 in
H 3.46
Max hydromod Q through underdrain 0.04884 cfs
Footprint of the BMP 3608 ft^2
Media filtration rate to be used for sizing (maximum filtration rate
of 5 in/hr. with no outlet control; if the filtration rate is controlled
by the outlet use the outlet controlled rate (includes infiltration
into the soil and flow rate through the outlet structure) which will
be less than 5 in/hr.)0.58 in/hr
Project Name
BMP ID
Sizing Method for Pollutant Removal Criteria
1 108312 sq. ft.
2 0.668674699
3 0.515 inches
4 3108 cu. ft.
5 6 inches
6 24 inches
7 12 inches
8 3 inches
9 0.2 in/in
10 0.4 in/in
11 0.58 in/hr.
12 6 hours
13 3.48 inches
15 20.28 inches
16 4662 cu. ft.
17 2759 sq. ft.
18 2331 cu. ft.
19 1665 sq. ft.
20 0.03
21 2173 sq. ft.
22 2173 sq. ft.
23 3608 sq. ft.
24 Is Line 23 ≥ Line 22?Yes, Performance Standard is Met
1
Nakano
Provided BMP Footprint
Worksheet B.5-1
Area draining to the BMP
BMP Parameters
Surface ponding [6 inch minimum, 12 inch maximum]
Baseline Calculations
Allowable routing time for sizing
14 16.8 inches
Option 1 – Biofilter 1.5 times the DCV
Required Footprint [Line 18/ Line 14] x 12
Minimum BMP Footprint [Line 1 x Line 2 x Line 20]
Footprint of the BMP = Maximum(Minimum(Line 17, Line 19), Line 21)
Footprint of the BMP
BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum footprint
sizing factor from Line 11 in Worksheet B.5-4)
Required Footprint [Line 16/ Line 15] x 12
Required biofiltered volume [1.5 x Line 4]
Option 2 - Store 0.75 of remaining DCV in pores and ponding
Required Storage (surface + pores) Volume [0.75 x Line 4]
Depth of Detention Storage
[Line 5 + (Line 6 x Line 9) + (Line 7 x Line 10) + (Line 8 x Line 10)]
Total Depth Treated [Line 13 + Line 14]
Depth filtered during storm [ Line 11 x Line 12]
Media thickness [18 inches minimum], also add mulch layer and washed ASTM 33
fine aggregate sand thickness to this line for sizing calculations
Aggregate storage (also add ASTM No 8 stone) above underdrain invert (12 inches
typical) – use 0 inches if the aggregate is not over the entire bottom surface area
Aggregate storage below underdrain invert (3 inches minimum) – use 0 inches if
the aggregate is not over the entire bottom surface area
Freely drained pore storage of the media
Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)
85th percentile 24-hour rainfall depth
Design capture volume [Line 1 x Line 2 x (Line 3/12)]
Porosity of aggregate storage
Media filtration rate to be used for sizing (maximum filtration rate of 5 in/hr. with no
outlet control; if the filtration rate is controlled by the outlet use the outlet controlled
rate (includes infiltration into the soil and flow rate through the outlet structure)
which will be less than 5 in/hr.)
ATTACHMENT 1B: Worksheet B.2-1: DCV
85th percentile 24-hr storm depth from Figure B.1.=0.515 in
DMA ID BMP ID
BMP Drainage
Area (ac)
BMP Drainage
Area (SF)
Impervious
Area (ac)
Amended
Soils (ac)
(C=0.1)
Natural A
Soils (ac)
(C=0.1)
Natural B
Soils (ac)
(C=0.14)
Natural C
Soils (ac)
(C=0.23)
Natural D
Soils (ac)
(C=0.3)
%
Impervious Composite C
1
Tree Credit
Volume (cf)
Rain Barrels
Credit
Volume (cf)
Design
Capture
Volume
(DCV) (CF)
2 2 4.01 174893 2.41 0.75 0.86 60.1%0.609 4571
Notes:
1) Equation for composite C factor = (0.9*Impervious Area +C*Pervious Area)/Total Area per BMP Design Manual.
C factors are from Table B.1-1 of Aug 2021 City BMP Design Manual.
CALCULATION FOR MEDIA FILTRATION RATE WHEN CONTROLLED BY UNDERDRAIN ORIFICE
Surface ponding [6 inch minimum, 12 inch maximum]6
Media thickness [18 inches minimum], also add mulch layer and
washed ASTM 33 fine aggregate sand thickness to this line for
sizing calculations 24
Aggregate storage (also add ASTM No 8 stone) above underdrain
invert (12 inches typical) – use 0 inches if the aggregate is not over
the entire bottom surface area 12
Diameter of underdrain orifice 1 in
H 3.46
Max hydromod Q through underdrain 0.04884 cfs
Footprint of the BMP 684 ft^2
Media filtration rate to be used for sizing (maximum filtration rate
of 5 in/hr. with no outlet control; if the filtration rate is controlled
by the outlet use the outlet controlled rate (includes infiltration
into the soil and flow rate through the outlet structure) which will
be less than 5 in/hr.)3.08 in/hr
Project Name
BMP ID
Sizing Method for Pollutant Removal Criteria
1 174893 sq. ft.
2 0.608927681
3 0.515 inches
4 4571 cu. ft.
5 6 inches
6 24 inches
7 15 inches
8 3 inches
9 0.2 in/in
10 0.4 in/in
11 3.08 in/hr.
12 6 hours
13 18.5069092 inches
15 36.5069092 inches
16 6856 cu. ft.
17 2254 sq. ft.
18 3428 cu. ft.
19 2285 sq. ft.
20 0.03
21 3195 sq. ft.
22 3195 sq. ft.
23 4523 sq. ft.
24 Is Line 23 ≥ Line 22?Yes, Performance Standard is Met
2
Nakano
Provided BMP Footprint
Worksheet B.5-1
Area draining to the BMP
BMP Parameters
Surface ponding [6 inch minimum, 12 inch maximum]
Baseline Calculations
Allowable routing time for sizing
14 18 inches
Option 1 – Biofilter 1.5 times the DCV
Required Footprint [Line 18/ Line 14] x 12
Minimum BMP Footprint [Line 1 x Line 2 x Line 20]
Footprint of the BMP = Maximum(Minimum(Line 17, Line 19), Line 21)
Footprint of the BMP
BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum footprint
sizing factor from Line 11 in Worksheet B.5-4)
Required Footprint [Line 16/ Line 15] x 12
Required biofiltered volume [1.5 x Line 4]
Option 2 - Store 0.75 of remaining DCV in pores and ponding
Required Storage (surface + pores) Volume [0.75 x Line 4]
Depth of Detention Storage
[Line 5 + (Line 6 x Line 9) + (Line 7 x Line 10) + (Line 8 x Line 10)]
Total Depth Treated [Line 13 + Line 14]
Depth filtered during storm [ Line 11 x Line 12]
Media thickness [18 inches minimum], also add mulch layer and washed ASTM 33
fine aggregate sand thickness to this line for sizing calculations
Aggregate storage (also add ASTM No 8 stone) above underdrain invert (12 inches
typical) – use 0 inches if the aggregate is not over the entire bottom surface area
Aggregate storage below underdrain invert (3 inches minimum) – use 0 inches if
the aggregate is not over the entire bottom surface area
Freely drained pore storage of the media
Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)
85th percentile 24-hour rainfall depth
Design capture volume [Line 1 x Line 2 x (Line 3/12)]
Porosity of aggregate storage
Media filtration rate to be used for sizing (maximum filtration rate of 5 in/hr. with no
outlet control; if the filtration rate is controlled by the outlet use the outlet controlled
rate (includes infiltration into the soil and flow rate through the outlet structure)
which will be less than 5 in/hr.)
ATTACHMENT 1B: Worksheet B.2-1: DCV
85th percentile 24-hr storm depth from Figure B.1.=0.515 in
DMA ID BMP ID
BMP Drainage
Area (ac)
BMP Drainage
Area (SF)
Impervious
Area (ac)
Amended
Soils (ac)
(C=0.1)
Natural A
Soils (ac)
(C=0.1)
Natural B
Soils (ac)
(C=0.14)
Natural C
Soils (ac)
(C=0.23)
Natural D
Soils (ac)
(C=0.3)
%
Impervious Composite C
1
Tree Credit
Volume (cf)
Rain Barrels
Credit
Volume (cf)
Design
Capture
Volume
(DCV) (CF)
3 3 13.8 601134 8.95 2.95 1.9 0 64.9%0.637 16427
Notes:
1) Equation for composite C factor = (0.9*Impervious Area +C*Pervious Area)/Total Area per BMP Design Manual.
C factors are from Table B.1-1 of Aug 2021 City BMP Design Manual.
Vault Drawdown
1 - EX10 - Flow (Total In)1 - EX10 - Flow (Total Out)1 - EX10 - Volume 1 - EX10 - Elevation CM-1 - EX10 - Flow (Total)O-1 - EX10 - Flow
Fl
o
w
(
f
t
³
/
s
)
12.50
11.25
10.00
8.75
7.50
6.25
5.00
3.75
2.50
1.25
0.00
Time (min)
6,000.0005,400.0004,800.0004,200.0003,600.0003,000.0002,400.0001,800.0001,200.000600.0000.000
Vo
l
u
m
e
(
a
c
-
f
t
)
1.500
1.375
1.250
1.125
1.000
0.875
0.750
0.625
0.500
0.375
0.250
0.125
0.000
El
e
v
a
t
i
o
n
(
f
t
)
104.40
103.80
103.20
102.60
102.00
101.40
100.80
100.20
99.60
99.00
98.40
Appendix B:
Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
BMP Design Manual-Appendices B-22
August 2021 Update
Figure B.4-1: Percent Capture Nomograph
Appendix B:
Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
BMP Design Manual-Appendices B-44
August 2021 Update
B.5.2.2 Sizing Biofiltration BMPs Downstream of a Storage Unit
Introduction
In scenarios, where the BMP footprint is governed based on Option 1 (Line 17 of Worksheet B.5-1)
or the required volume reduction for partial infiltration conditions (Line 10 of Worksheet B.5-2) the
footprint of the biofiltration BMP can be reduced using the sizing calculations in this Appendix
B.5.2.2 when there is an upstream storage unit (e.g. cistern) that can be used to regulate the flows
through the biofiltration BMP.
When this approach is used for sizing biofiltration BMPs the applicant must also verify that the storage
unit meets the hydromodification management drawdown requirements and the discharge from the
downstream biofiltration BMP will still meet the hydromodication flow control requirements. These
calculations must be documented in the PDP SWQMP.
This methodology is not applicable when the minimum footprint factor is governed based on the
alternative minimum footprint sizing factor calculated using Worksheet B.5-4 (Line 11). A
biofiltration BMP smaller than the alternative minimum footprint sizing factor is considered compact
biofiltration BMP and may be allowed at the discretion of the City Engineer if the BMP meets the
requirements in Appendix F and the applicant submits a completed Form I-10.
Sizing Calculation
Sizing calculations for the biofiltration footprint must demonstrate that one of the following two
equivalent performance standards is met:
1. Use continuous simulation and demonstrate the following is met:
(a) The BMP or series of BMPs biofilters at least 92 percent of average annual (long term) runoff
volume and achieves a volume reduction equivalent to Line 10 of Worksheet B.5-2. This can
be demonstrated through reporting of output from the San Diego Hydrology Model, or
through other continuous simulation modeling meeting the criteria in Appendix G, as
acceptable to the City Engineer. The 92 percent of average annual runoff treatment
corresponds to the average capture achieved by implementing a BMP with 1.5 times the DCV
and a drawdown time of 36 hours (Appendix B.4.2).
2. Use the simple optimized method in Worksheet B.5-5. The applicant is also required to
complete Worksheet B.5-1, B.5-2 and B.5-4 when the applicant elects to use Worksheet B.5-5 to
reduce the biofiltration BMP footprint. Worksheet B.5-5 was developed to satisfy the following
two criteria as applicable:
(a) Greater than 92 percent of the average annual runoff volume from the storage unit is routed
to the biofiltration BMP through the low flow orifice and the peak flow from the low flow
orifice can instantaneously be filtered through the biofiltration media. If the outlet design for
the storage unit includes orifices at different elevations and an overflow structure, only
flows from the overflow structure should be excluded from the calculation (both for 92
percent capture and for peak flow to the biofiltration BMP that needs to be instantaneously
filtered), unless the flows from other orifices also bypass the biofiltration BMP, in which case
flows from the orifices that bypass should also be excluded.
Drawdown
Time (hours)
Storage requirement (below the overflow elevation, or below
outlet elevation that bypass the biofiltration BMP)
12 0.85 DCV
24 1.25 DCV
36 1.50 DCV
48 1.80 DCV
72 2.20 DCV
96 2.60 DCV
120 2.80 DCV
Table B.5-5
Nakano Project MWS Calculations
Project Site DCV= 16427 ft3
96 hour drawdown=2.6*DCV
2.6*DCV= 42710 ft3
Qavg=Volume/(96*3600)
Qavg=0.124 cfs
Conversion
Qavg=55.46 gpm 448.8 gpm/cfs
Volume based loading rate 0.28 gpm/sf
Loading Rate = Qavg/Afilter
Afilter= Perimeter length * Height Height used= 4.5 ft
P=44.02 ft
Perimeter Capacity of 8-24 Unit=88.8 ft
44.02 ft<88.8 ft
MWS 8-24 Unit will work
STANDARD DETAIL
STORMWATER BIOFILTRATION SYSTEM
MWS-L-8-24-5'-11"-V
SITE SPECIFIC DATA
PLAN VIEW
ELEVATION VIEW
RIGHT END VIEW
LEFT END VIEW
GENERAL NOTES
INSTALLATION NOTES
398 Via El Centro, Oceanside, CA 92058
(469) 458-7973 • Fax (760) 433-3176
www.biocleanenvironmental.com
MWS SIZING
Nakano
Chula Vista, CA
Mike Billings
06/23/2022
398 Via El Centro, Oceanside, CA 92058
(469) 458-7973 • Fax (760) 433-3176
www.biocleanenvironmental.com
The MWS Linear will be sized in accordance with its TAPE GULD approval. The system is approved at a
loading rate of 1 gpm/sq ft. The MWS Linear has General Use Level Designation at this loading rate for
TSS (Basic), phosphorous and dissolved metals (Enhanced). For this project design, sizing, loading will be
reviewed by a Modular Wetland representative for final approval to ensure the system is sized
appropriately.
For this project we are sizing the MWS units to treat a large volume. Due to this large volume, we are
using a 72% safety factor on our media loading rate and only sizing at a loading rate of 0.277 gpm/sf.
Using a safety factor between 65% and 75% will greatly prolong the life of the WetlandMEDIA and
decrease the long‐term maintenance costs.
The orifice has been sized using the standard orifice sizing below. Sizing is based on the discharge rate of
110.69 gpm split between the two orifices. 110.69 gpm/2 = 55.35 gpm
𝑴𝑾𝑺 𝑶𝑹𝑰𝑭𝑰𝑪𝑬 𝑺𝑰𝒁𝑰𝑵𝑮
𝐺𝑖𝑣𝑒𝑛 𝑡ℎ𝑎𝑡: 𝑄ൌ𝑉𝐴; 𝑄 ൌ 𝑡𝑟𝑒𝑎𝑡𝑚𝑒𝑛𝑡 𝑓𝑙𝑜𝑤 𝑟𝑎𝑡𝑒,𝑉ൌ 𝑐ௗ ඥ2𝑔ℎ ,𝐴ൌ 𝜋𝐷ଶ
4
𝑐ௗ 𝑖𝑠 𝑡ℎ𝑒 𝑑𝑖𝑠𝑐ℎ𝑎𝑟𝑔𝑒 𝑐𝑜𝑒𝑓𝑓𝑖𝑐𝑒𝑛𝑡 & ℎ 𝑖𝑠 𝑡ℎ𝑒 𝑡𝑟𝑒𝑎𝑡𝑚𝑒𝑛𝑡 𝐻𝐺𝐿
𝑅𝑒𝑤𝑟𝑖𝑡𝑒 𝑡𝑜 𝑠𝑜𝑙𝑣𝑒 𝑓𝑜𝑟 𝑡ℎ𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑡ℎ𝑒 𝑜𝑟𝑖𝑓𝑖𝑐𝑒.
𝐴 ൌ 𝑄
𝑉൨ ௪௧ሱ⎯⎯⎯⎯ሮ 𝜋𝐷ଶ
4 ൌ 𝑄
𝑐ௗ ඥ2𝑔ℎ
𝐷ൌ ඨ 4𝑄
𝜋𝑐ௗ ඥ2𝑔ℎ; 𝑐ௗ ൌ 𝑐௩ 𝑐 ൌሺ0.98ሻሺ0.62ሻൌ0.6076
MWS-L-8-24-V-HC:
𝐺𝑖𝑣𝑒𝑛:𝑄ൌ55.35 𝑔𝑝𝑚ሺ𝑝𝑒𝑟 𝑜𝑟𝑖𝑓𝑖𝑐𝑒ሻ ൌ 𝟎.𝟏𝟐𝟑 𝒄𝒇𝒔 ,ℎൌ4.5 𝑓𝑡
𝐷ൌ ඨ 4ሺ0.123ሻ
𝜋ሺ0.6076ሻඥ2ሺ32.17ሻሺ4.5ሻ ൌ 0.123ᇱ ൌ 1.48" 𝑒𝑎𝑐ℎ
𝑇ℎ𝑒 𝑑𝑖𝑎𝑚𝑒𝑡𝑒𝑟 𝑜𝑓 𝑒𝑎𝑐ℎ 𝑜𝑟𝑖𝑓𝑖𝑐𝑒 𝑛𝑒𝑒𝑑𝑠 𝑡𝑜 𝑏𝑒 1.48" 𝑖𝑛 𝑜𝑟𝑑𝑒𝑟 𝑡𝑜 𝑝𝑟𝑜𝑑𝑢𝑐𝑒 𝑎 ℎ𝑒𝑎𝑑 𝑜𝑓
4.5ᇱ 𝑖𝑛 𝑡ℎ𝑒 𝑀𝑊𝑆 𝑢𝑛𝑖𝑡.
July 2017
GENERAL USE LEVEL DESIGNATION FOR BASIC, ENHANCED, AND
PHOSPHORUS TREATMENT
For the
MWS-Linear Modular Wetland
Ecology’s Decision:
Based on Modular Wetland Systems, Inc. application submissions, including the Technical
Evaluation Report, dated April 1, 2014, Ecology hereby issues the following use level
designation:
1. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Basic treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
2. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Phosphorus treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
3. General use level designation (GULD) for the MWS-Linear Modular Wetland Stormwater
Treatment System for Enhanced treatment
Sized at a hydraulic loading rate of 1 gallon per minute (gpm) per square foot (sq ft) of
wetland cell surface area. For moderate pollutant loading rates (low to medium density
residential basins), size the Prefilters at 3.0 gpm/sq ft of cartridge surface area. For high
loading rates (commercial and industrial basins), size the Prefilters at 2.1 gpm/sq ft of
cartridge surface area.
4. Ecology approves the MWS - Linear Modular Wetland Stormwater Treatment System units
for Basic, Phosphorus, and Enhanced treatment at the hydraulic loading rate listed above.
Designers shall calculate the water quality design flow rates using the following procedures:
Western Washington: For treatment installed upstream of detention or retention, the
water quality design flow rate is the peak 15-minute flow rate as calculated using the
latest version of the Western Washington Hydrology Model or other Ecology-approved
continuous runoff model.
Eastern Washington: For treatment installed upstream of detention or retention, the
water quality design flow rate is the peak 15-minute flow rate as calculated using one of
the three methods described in Chapter 2.2.5 of the Stormwater Management Manual
for Eastern Washington (SWMMEW) or local manual.
Entire State: For treatment installed downstream of detention, the water quality design
flow rate is the full 2-year release rate of the detention facility.
5. These use level designations have no expiration date but may be revoked or amended by
Ecology, and are subject to the conditions specified below.
Ecology’s Conditions of Use:
Applicants shall comply with the following conditions:
1. Design, assemble, install, operate, and maintain the MWS – Linear Modular Wetland
Stormwater Treatment System units, in accordance with Modular Wetland Systems, Inc.
applicable manuals and documents and the Ecology Decision.
2. Each site plan must undergo Modular Wetland Systems, Inc. review and approval before
site installation. This ensures that site grading and slope are appropriate for use of a MWS
– Linear Modular Wetland Stormwater Treatment System unit.
3. MWS – Linear Modular Wetland Stormwater Treatment System media shall conform to the
specifications submitted to, and approved by, Ecology.
4. The applicant tested the MWS – Linear Modular Wetland Stormwater Treatment System
with an external bypass weir. This weir limited the depth of water flowing through the
media, and therefore the active treatment area, to below the root zone of the plants. This
GULD applies to MWS – Linear Modular Wetland Stormwater Treatment Systems whether
plants are included in the final product or not.
5. Maintenance: The required maintenance interval for stormwater treatment devices is often
dependent upon the degree of pollutant loading from a particular drainage basin. Therefore,
Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a
particular model/size of manufactured filter treatment device.
Typically, Modular Wetland Systems, Inc. designs MWS - Linear Modular Wetland
systems for a target prefilter media life of 6 to 12 months.
Indications of the need for maintenance include effluent flow decreasing to below the
design flow rate or decrease in treatment below required levels.
Owners/operators must inspect MWS - Linear Modular Wetland systems for a minimum
of twelve months from the start of post-construction operation to determine site-specific
maintenance schedules and requirements. You must conduct inspections monthly during
the wet season, and every other month during the dry season. (According to the
SWMMWW, the wet season in western Washington is October 1 to April 30. According
to SWMMEW, the wet season in eastern Washington is October 1 to June 30). After the
first year of operation, owners/operators must conduct inspections based on the findings
during the first year of inspections.
Conduct inspections by qualified personnel, follow manufacturer’s guidelines, and use
methods capable of determining either a decrease in treated effluent flowrate and/or a
decrease in pollutant removal ability.
When inspections are performed, the following findings typically serve as maintenance
triggers:
Standing water remains in the vault between rain events, or
Bypass occurs during storms smaller than the design storm.
If excessive floatables (trash and debris) are present (but no standing water or
excessive sedimentation), perform a minor maintenance consisting of gross solids
removal, not prefilter media replacement.
Additional data collection will be used to create a correlation between pretreatment
chamber sediment depth and pre-filter clogging (see Issues to be Addressed by the
Company section below)
6. Discharges from the MWS - Linear Modular Wetland Stormwater Treatment System units
shall not cause or contribute to water quality standards violations in receiving waters.
Applicant: Modular Wetland Systems, Inc.
Applicant's Address: PO. Box 869
Oceanside, CA 92054
Application Documents:
Original Application for Conditional Use Level Designation, Modular Wetland System,
Linear Stormwater Filtration System Modular Wetland Systems, Inc., January 2011
Quality Assurance Project Plan: Modular Wetland system – Linear Treatment System
performance Monitoring Project, draft, January 2011.
Revised Application for Conditional Use Level Designation, Modular Wetland System,
Linear Stormwater Filtration System Modular Wetland Systems, Inc., May 2011
Memorandum: Modular Wetland System-Linear GULD Application Supplementary Data,
April 2014
Technical Evaluation Report: Modular Wetland System Stormwater Treatment System
Performance Monitoring, April 2014.
Applicant's Use Level Request:
General use level designation as a Basic, Enhanced, and Phosphorus treatment device in
accordance with Ecology’s Guidance for Evaluating Emerging Stormwater Treatment
Technologies Technology Assessment Protocol – Ecology (TAPE) January 2011 Revision.
Applicant's Performance Claims:
The MWS – Linear Modular wetland is capable of removing a minimum of 80-percent
of TSS from stormwater with influent concentrations between 100 and 200 mg/l.
The MWS – Linear Modular wetland is capable of removing a minimum of 50-percent
of Total Phosphorus from stormwater with influent concentrations between 0.1 and 0.5
mg/l.
The MWS – Linear Modular wetland is capable of removing a minimum of 30-percent
of dissolved Copper from stormwater with influent concentrations between 0.005 and
0.020 mg/l.
The MWS – Linear Modular wetland is capable of removing a minimum of 60-percent
of dissolved Zinc from stormwater with influent concentrations between 0.02 and 0.30
mg/l.
Ecology Recommendations:
Modular Wetland Systems, Inc. has shown Ecology, through laboratory and field-
testing, that the MWS - Linear Modular Wetland Stormwater Treatment System filter
system is capable of attaining Ecology's Basic, Total phosphorus, and Enhanced
treatment goals.
Findings of Fact:
Laboratory Testing
The MWS-Linear Modular wetland has the:
Capability to remove 99 percent of total suspended solids (using Sil-Co-Sil 106) in a
quarter-scale model with influent concentrations of 270 mg/L.
Capability to remove 91 percent of total suspended solids (using Sil-Co-Sil 106) in
laboratory conditions with influent concentrations of 84.6 mg/L at a flow rate of 3.0
gpm per square foot of media.
Capability to remove 93 percent of dissolved Copper in a quarter-scale model with
influent concentrations of 0.757 mg/L.
Capability to remove 79 percent of dissolved Copper in laboratory conditions with
influent concentrations of 0.567 mg/L at a flow rate of 3.0 gpm per square foot of
media.
Capability to remove 80.5-percent of dissolved Zinc in a quarter-scale model with
influent concentrations of 0.95 mg/L at a flow rate of 3.0 gpm per square foot of media.
Capability to remove 78-percent of dissolved Zinc in laboratory conditions with influent
concentrations of 0.75 mg/L at a flow rate of 3.0 gpm per square foot of media.
Field Testing
Modular Wetland Systems, Inc. conducted monitoring of an MWS-Linear (Model
# MWS-L-4-13) from April 2012 through May 2013, at a transportation maintenance
facility in Portland, Oregon. The manufacturer collected flow-weighted composite
samples of the system’s influent and effluent during 28 separate storm events. The
system treated approximately 75 percent of the runoff from 53.5 inches of rainfall
during the monitoring period. The applicant sized the system at 1 gpm/sq ft. (wetland
media) and 3gpm/sq ft. (prefilter).
Influent TSS concentrations for qualifying sampled storm events ranged from 20 to 339
mg/L. Average TSS removal for influent concentrations greater than 100 mg/L (n=7)
averaged 85 percent. For influent concentrations in the range of 20-100 mg/L (n=18),
the upper 95 percent confidence interval about the mean effluent concentration was
12.8 mg/L.
Total phosphorus removal for 17 events with influent TP concentrations in the range of
0.1 to 0.5 mg/L averaged 65 percent. A bootstrap estimate of the lower 95 percent
confidence limit (LCL95) of the mean total phosphorus reduction was 58 percent.
The lower 95 percent confidence limit of the mean percent removal was 60.5 percent for
dissolved zinc for influent concentrations in the range of 0.02 to 0.3 mg/L (n=11).
The lower 95 percent confidence limit of the mean percent removal was 32.5 percent for
dissolved copper for influent concentrations in the range of 0.005 to 0.02 mg/L (n=14)
at flow rates up to 28 gpm (design flow rate 41 gpm). Laboratory test data augmented
the data set, showing dissolved copper removal at the design flow rate of 41 gpm (93
percent reduction in influent dissolved copper of 0.757 mg/L).
Issues to be addressed by the Company:
1. Modular Wetland Systems, Inc. should collect maintenance and inspection data for the
first year on all installations in the Northwest in order to assess standard maintenance
requirements for various land uses in the region. Modular Wetland Systems, Inc. should
use these data to establish required maintenance cycles.
2. Modular Wetland Systems, Inc. should collect pre-treatment chamber sediment depth
data for the first year of operation for all installations in the Northwest. Modular
Wetland Systems, Inc. will use these data to create a correlation between sediment depth
and pre-filter clogging.
Technology Description:
Download at http://www.modularwetlands.com/
Contact Information:
Applicant: Zach Kent
BioClean A Forterra Company.
398 Vi9a El Centro
Oceanside, CA 92058
zach.kent@forterrabp.com
Applicant website: http://www.modularwetlands.com/
Ecology web link: http://www.ecy.wa.gov/programs/wg/stormwater/newtech/index.html
Ecology: Douglas C. Howie, P.E.
Department of Ecology
Water Quality Program
(360) 407-6444
douglas.howie@ecy.wa.gov
Revision History
Date Revision
June 2011 Original use-level-designation document
September 2012 Revised dates for TER and expiration
January 2013 Modified Design Storm Description, added Revision Table, added
maintenance discussion, modified format in accordance with Ecology
standard
December 2013 Updated name of Applicant
April 2014 Approved GULD designation for Basic, Phosphorus, and Enhanced
treatment
December 2015 Updated GULD to document the acceptance of MWS-Linear
Modular Wetland installations with or without the inclusion of plants
July 2017 Revised Manufacturer Contact Information (name, address, and
email)
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 2
Backup for PDP Hydromodification Control
Measures
Mark this box if this attachment is empty because the project is exempt from PDP
hydromodification management requirements.
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Indicate which Items are Included
Attachment
Sequence
Contents Checklist
Attachment 2A
Hydromodification Management
Exhibit (Required)
Included
See Hydromodification Management
Exhibit Checklist.
Attachment 2B
Management of Critical Coarse
Sediment Yield Areas (WMAA
Exhibit is required, additional
analyses are optional)
See Section 6.2 of the BMP Design
Manual.
Exhibit showing project drainage
boundaries marked on WMAA Critical
Coarse Sediment Yield Area Map
(Required)
Optional analyses for Critical Coarse
Sediment Yield Area Determination
6.2.1 Verification of Geomorphic
Landscape Units Onsite
6.2.2 Downstream Systems
Sensitivity to Coarse Sediment
6.2.3 Optional Additional Analysis of
Potential Critical Coarse Sediment
Yield Areas Onsite
Attachment 2C
Geomorphic Assessment of
Receiving Channels (Optional)
See Section 6.3.4 of the BMP
Design Manual.
Not performed
Included
Submitted as separate stand-alone
document
Attachment 2D
Flow Control Facility Design and
Structural BMP Drawdown
Calculations (Required)
Overflow Design Summary for each
Structural BMP
See Chapter 6 and Appendix G of
the BMP Design Manual
Included
Submitted as separate stand-alone
document
FOR HYDROMODIFICATION
MANAGEMENT EXHIBIT SEE
ATTACHMENT A OF
HYDROMODIFICATION STUDY IN
ATTACHMENT 2D
ATTACHMENT 2B
MANAGEMENT OF CRITICAL
COARSE SEDIMENT YIELD AREAS
LEGEND
CITY OF CHULA VISTA
NAKANO
ATTACHMENT 2D
FLOW CONTROL FACILITY DESIGN
AND STRUCTURAL BMP DRAWDOWN
CALCULATIONS
Preliminary Hydromodification Management
Study
NAKANO
City of Chula Vista TM#PCS21-0001,
City of San Diego PTS 647766
City of Chula Vista CA
November 3, 2022
Prepared for:
TriPointe Homes
13400 Sabre Springs Parkway, Suite 200
San Diego, California 92128
Prepared By:
PDC Job No. 4409.02
Prepared by: J. Novoa, PE
Under the supervision of
________________________________
Chelisa Pack, PE RCE 71026
Registration Expires 06/30/23
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1
1. INTRODUCTION
This report summarizes the preliminary hydromodification design for the Nakano development
Project for a Tentative Map (TM) submittal located in the City of Chula Vista, CA. The
hydromodification calculations were performed utilizing continuous simulation analysis to size
the storm water treatment and control facilities. Storm Water Management Model (SWMM)
version 5.1 distributed by USEPA is the basis of both existing and proposed conditions modeling
within this report. The biofiltration basin/hydromodification basin sizing and link configuration
with the specialized outlet configuration ensures compliance with the Hydromodification
Management Plan (HMP) requirements from the San Diego Regional Water Quality Control Board
(SDRWQCB).
2. HYDROMODIFICATION MODELING OVERVIEW
2. 1 Model Description
PCSWMM is a proprietary software which utilizes the EPA’s Stormwater Management Model
(SWMM) as its computational engine, while providing added processing and analytical
capabilities to streamline design. PCSWMM is essentially a user-friendly shell for SWMM that
allows rapid development and analysis of SWMM models.
PCSWMM was employed for this study based on the ability to efficiently create, edit and compare
models, perform detention routing with the same software, and moreover, due to the tendency for
SWMM to produce results that have been found to more accurately represent San Diego area
watersheds than the alternative San Diego Hydrology Model (SDHM).
SWMM is a semi-distributed hydrologic and hydraulic modeling software that simulates the
rainfall-runoff response of a watershed based on linear-reservoir overland flow routing. This
overland flow routine accounts for the connectedness of pervious, impervious, and Low Impact
Development (LID) BMPs to the drainage system. LID BMPs are represented with a module in
SWMM that simulates the water balance through standard LID BMP components, accounting for
soil percolation, evapotranspiration, underdrain outflow, various media layer storage and subgrade
infiltration (if applicable). These controls provide a wide range of customizability between the
various associated parameters and the ability to route underdrain or overflow to other SWMM
elements, like Storages Nodes and conduits to represent almost any conceivable LID system.
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2
The outflow from these LID controls, storage components or watersheds is translated into the
hydraulic component of the model that utilizes energy and momentum principles to determine flow
through conduits, orifices and other structures. The hydraulics may be computed based on either
the kinematic or dynamic-wave equations. In this study the former was used because there was no
need to take downstream hydraulic grade line effects into consideration.
2.2 Hydromodification Criteria
The San Diego Regional Water Quality Control Board (SDRWQCB) requires the exceedance
duration of post-developed flow rates be maintained to within 10% of the pre-developed flow
durations. This must occur for flow frequencies ranging from a fraction of the 2-year flow (Q2) to
the 10-year flow (Q10). These flow frequency values may be calculated directly from SWMM
statistics or estimated based on accepted USGS regression equations. These equations estimate
flows based on a correlation with watershed area and the mean annual rainfall developed for the
region. For this project the SWMM output was used because of the exceedingly small values
calculated by regression equations, which were developed with data from significantly larger
watersheds.
The fraction of the Q2 that must be controlled is dependent on the relative erodibility of the channel
being discharged to, categorized as either High, Medium, or Low susceptibility. By default it is
assumed that all channels have a High susceptibility, and that therefore the low flow threshold of
0.1 of the Q2 must be controlled. A Geomorphic Assessment of Receiving Channels may be
performed to indicate whether the channel erosion susceptibility can be categorized as Medium or
Low, allowing control to 0.3 or 0.5 of the Q2, respectively.
The low-flow threshold used in the analysis for Nakano project for POCs 1 and 2 are the default
0.1Q2 low-flow threshold, as determined as “high susceptibility”. A geomorphic assessment report
may be completed in the future to achieve a low or medium susceptibility, but is not completed as
this time.
2.3 Model Development
The inputs required for a SWMM model include rainfall, evapotranspiration rates, watershed
characteristics and BMP configurations. The sources for some of these parameters are provided in
Table 1 below.
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Table 1: Hydrology Criteria
Rain Gage ‘Bonita’ – from Project Clean Water website
Evapotranspiration
Daily E-T Rates taken from Table G.1-1 in the City of Chula
Vista BMP Design Manual based on location in Zone 6 of
California irrigation Management Information System
“Reference Evapotranspiration Zones”
Overland Flow Path Length
Based on available digital topographic data for pre-
development conditions and proposed grading plan for post-
project conditions.
Soils/Green-Ampt Parameters
Values for Hydrologic Soil Group ‘C and D’ taken from Table
G.1-4 in the City of San Diego BMP Design Manual. A 25%
reduction is applied whenever native soils are compacted.
The drainage area to each point of compliance (POC) was delineated with the project boundary
plus adjacent land that drain through the site for both existing and proposed conditions. For the
proposed model this drainage area has been broken up into the contributing drainage management
(DMA) areas that drain to BMPs. DMAs 1 and 3 flow to POC 1 and outlet via sheet to the flow
north. POC 2 contains flow from DMA 2 and outlets east of POC 1 via sheet flow north as well.
See the Storm Water Quality Management Plan (SWQMP) for more information regarding the
pollutant control strategy and DMAs.
The overland flow path lengths were drawn from a visual inspection of the watershed contours,
extending from the upper ridge to the apparent flow path, perpendicular to the contours. The
percent imperviousness was calculated based on the estimated imperviousness in the site plan to
develop the same values used to calculate the Design Capture Volume provided in Attachment 1e
of the SWQMP.
3. Modeling for Hydromodification Compliance
The pre-developed conditions for the site were modelled based on the existing topography and
landcover with zero imperviousness. For the post-developed condition, the proposed site footprint
was represented as an equivalent imperviousness and a short overland flow path length typical of
urban drainage systems. The lined biofiltration basins were modelled by coupling the bioretention
LID component to properly represent the media and underdrain, with the storage component to
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4
represent the basin surface storage. The parameters utilized for the biofiltration parameters were
based on the published values in the City of Chula Vista BMP Design Manual. The basins outlet
to new proposed private storm drains that discharges and sheet flow north just before Otay River.
It was determined that this suite of BMPs would be sufficient to provide flow control with the
storage depths and outlet size provided herein based on the SWMM modeling results. The Status
Report SWMM output files for the existing condition models are provided in Attachment D.
3.1 Flow Frequency Analysis
The SWMM statistics calculator was used to determine the pre-developed and post developed flow
rates for the 2, 5, and 10-year recurrence intervals. These are provided below with the resultant
low flow threshold. The SWMM output used to calculate these values is provided in Attachment
E.
The low-flow threshold used in the analysis for Nakano project for POCs 1 and 2 are the default
0.1Q2 low-flow threshold, as determined as “high susceptibility”.
Table 2 – Pre-Developed and Post-Mitigated Flows for POC 1 (BMP Basin 1 & BMP 3 MWS
& Vault)
Return Period Pre-project Qpeak
(cfs)
Post-project - Mitigated Q
(cfs)
LF = 0.1xQ2 0.326 0.327
2-year 3.263 3.274
5-year 4.477 4.516
10-year 5.760 5.804
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Table 3 – Pre-Developed and Post-Mitigated Flows for POC 2 (BMP Basin 2)
Return Period Pre-project Qpeak
(cfs)
Post-project - Mitigated Q
(cfs)
LF = 0.1xQ2 0.072 0.028
2-year 0.720 0.277
5-year 1.054 0.945
10-year 1.276 1.257
3.2 Biofiltration Basins
The basins are composed of above ground storage as well as biofiltration media. These components
were represented as an LID control (“Bio-retention cell”) in series with a storage node as simulated
in SWMM. The module allows the user to represent the various stages of a biofiltration basin
including ponding, media, and gravel storage above and below the underdrain. These layer depths
were assigned per the design developed for pollutant control as shown in Table 4 and the parameter
values were assigned with the standard values taken from Table G.1-7 in the BMP Design Manual
(with some refinement). The underdrain is offset to allow for the dead storage needed. The drain
coefficients are calculated based on media infiltration of 5 in/hr and basin layer depth and listed in
Table 4. Drain coefficient calculation is based on C factor calculation equation in the BMP Design
Manual (Page G-27).
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\Hydromod\4409.02 Nakano Prelim Hydromodification Study.docx
6
Table 4 – Biofiltration Model Summary
Biofiltration
BMP #
Surface
Area (sf)
Layer Depth Underdrain
Orifice
(in)
Drain
Coefficient Ponding (in) Soil (in) Gravel Storage (in)
1 3,608 6 24 12 1 0.0908
2 4,523 6 24 12 0.8 0.0593
Media and storage parameters taken from Table G.1-7 in BMP Design Manual, including media infiltration = 5 in/hr
To control the flows with this configuration, except for underdrain orifices, a series of flow orifices
were connected between the biofiltration basin storage node connected to the point of compliance.
The orifice design is summarized in Table 5. Additional screenshots of orifices and weirs are
provided in Attachment B. The offset elevation of the above ground orifices are taken from the
bottom of the storage node in PCSWMM which is the elevation above the water quality ponding
depth, typically 0.75’ above the basin bottom (0.5’ of WQ ponding and 0.25’ of mulch).
Table 5 – Biofiltration Orifice Design
Biofiltration
BMP #
Low Flow Orifice Overflow Weir
Dia. (in) Offset
(ft) Type Offset
(ft)
1 0.8 0.0 Modified
G-3 Riser 0.5
2 1 0.0 Modified
G-3 Riser 1
3.3 Detention/Hydromodification Underground Vault
A multi-use underground storage vault is utilized for DMA 3. The underground vault will detain
flows for the 100-year storm event, provide storage for hydromodification requirements and is also
utilized for storage upstream of a modular wetland unit for water quality treatment purposes. The
underground vault consists of a 5’ depth and approx. 12,736 bottom footprint, which contains a
weir wall within the vault. See below for the vault characteristics and parameters.
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\Hydromod\4409.02 Nakano Prelim Hydromodification Study.docx
7
Table 6 –Underground Vault Storage Summary
Hydromod
BMP #
Bottom
Footprint (sf)
Depth (ft)
BMP3 12,736 5
BMP #3
Riser Structure
Parameters
Size Height (ft)
2.2” orifice (within MWS)* 0.0
Weir Wall L=8’ 4.5
*One single orifice was modeled in the SWMM model. The MWS Unit utilizes two 1.48” orifices.
The equivalent flow out was calculated to be the same for the single orifice and two orifices, so
they act similarly.
3.4 Flow Duration Curves for Hydromodification Compliance
The pre and post developed flow duration exceedance curves were developed for the hourly flow
data using an automatic partial duration series calculator in PCSWMM. These curves are graphed
over the flow ranges listed in Tables 2 and 3 and are provided in Attachment F. In all cases the
duration of post developed flows are brought to well within that of the pre developed flows within
the low flow and high flow thresholds, indicating that the suite of BMPs will provide the flow
attenuation required for compliance.
4.0 SUMMARY
The predeveloped conditions of the Nakano project were modelled in SWMM to determine a
baseline of flow durations that would need to be controlled in the post-developed conditions. The
proposed development was also modelled in SWMM with biofiltration basins with storage as well
as detention/hydromodification vault. Based on the SWMM model results for this study it is
determined that the combination of two biofiltration basin and a hydromodification vault LID
BMPs will be able to satisfy the hydromodification criteria. This study is intended to demonstrate
that these controls as sized are capable of providing hydromodification compliance for the project.
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\Hydromod\4409.02 Nakano Prelim Hydromodification Study.docx
8
Attachments
A – Hydromodification Management Exhibit
B – SWMM Model w/ Subcatchment Schematics
C – SWMM Output – Existing Condition
D – SWMM Output – Proposed Conditions
E – Flow Frequency Statistical Analysis results
F – Flow Duration Curves
ATTACHMENT A
Hydromodification Management Exhibit
A
P1.1P2.1P1.1P3.1
B
P3.1
C
P2.2
A
P1.1P2.1P1.1P3.1
B
P3.1
C
P2.2
A
P1.1P2.1P3.1
C
P2.2
P1.1
P3.1
B
A
P1.1P2.1
P1.1
P3.1
B
P3.1
C
P2.2
A
P1.1P2.1
P3.1
C
P2.2
P3.1
C
P2.2
P1.1 P3.1
B
A
P1.1P2.1
A
P1.1 P2.1 P1.1 P3.1
B
P3.1
C
P2.2
A
P1.1 P2.1 P1.1 P3.1
B
P3.1
C
P2.2
A
P1.1 P2.1 P3.1
C
P2.2
A
P1.1P2.1P1.1P3.1
B
P3.1
C
P2.2
A
P1.1P2.1P1.1P3.1
B
P3.1
C
P2.2
A
P1.1P2.1
A
P1.1 P2.1
P1.1
P3.1
B
P3.1
C
P2.2
A
P1.1 P2.1
P3.1
C
P2.2
P1.1 P3.1
BP3.1
C
P2.2
A
P1.1 P2.1
P3.1
C
P2.2
P1.1 P3.1
B
P4A P3 P2 P1 P4BRP3RP2RP1RP3RP3P4AP3P2P1P4BRP3RP2RP1RP3RP3
P4A P3 P2 P1 P4BRP3RP2RP1RP3RP3P4AP3P2P1P4BRP3RP2RP1RP3RP3
P4AP2P1
P4BR P3R P2R P1R
P4AP2P1
P4BR P3R P2R P1R P4AP3P2P1
P4BR P3R P2R P1R
P4A
P3
P2
P1
P4BR P3R
P2R P1R
CITY OF CHULA VISTA
NAKANO
ATTACHMENT B
SWMM Model with
Sub-catchment Parameters and Schematic
Existing Conditions
POC 1
POC 2
Proposed Conditions
POC 1
Basin 1 PCSWMM LID & Orifice Parameters
Vault PCSWMM Orifice Parameters
POC 2
Basin 2 PCSWMM LID & Orifice Parameters
\
ATTACHMENT C
SWMM Output – Existing Conditions
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.015)
--------------------------------------------------------------
Pre Condition Nakano POC 1-DMA 1&3
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Starting Date ............ 10/03/1970 05:00:00
Ending Date .............. 05/25/2008 22:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 00:15:00
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 460.288 339.070
Evaporation Loss ......... 2.974 2.191
Infiltration Loss ........ 442.120 325.687
Surface Runoff ........... 15.795 11.635
Final Storage ............ 0.000 0.000
Continuity Error (%) ..... -0.131
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 15.795 5.147
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 15.795 5.147
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
***************************
Subcatchment Runoff Summary
***************************
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
DMA1 339.07 0.00 2.11 323.95 0.00 13.63 13.63 0.92 2.41 0.040
DMA3 339.07 0.00 2.20 326.00 0.00 11.28 11.28 4.23 11.46 0.033
Analysis begun on: Thu Jun 16 11:03:51 2022
Analysis ended on: Thu Jun 16 11:04:04 2022
Total elapsed time: 00:00:13
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.015)
--------------------------------------------------------------
Pre Condition Nakano POC 2- DMA 2
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Starting Date ............ 10/03/1970 05:00:00
Ending Date .............. 05/25/2008 22:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 00:15:00
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Total Precipitation ...... 113.306 339.070
Evaporation Loss ......... 0.725 2.169
Infiltration Loss ........ 108.638 325.102
Surface Runoff ........... 4.106 12.288
Final Storage ............ 0.000 0.000
Continuity Error (%) ..... -0.144
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 4.106 1.338
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 4.106 1.338
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
***************************
Subcatchment Runoff Summary
***************************
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
DMA2 339.07 0.00 2.17 325.10 0.00 12.29 12.29 1.34 3.64 0.036
Analysis begun on: Thu Jun 16 10:50:43 2022
Analysis ended on: Thu Jun 16 10:50:55 2022
Total elapsed time: 00:00:12
ATTACHMENT D
SWMM Output – Proposed Conditions
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.015)
--------------------------------------------------------------
Post Condition Nakano POC 1- DMA 1&3
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Flow Routing Method ...... KINWAVE
Starting Date ............ 10/03/1970 05:00:00
Ending Date .............. 05/25/2008 22:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 00:15:00
Routing Time Step ........ 15.00 sec
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Initial LID Storage ...... 0.017 0.012
Total Precipitation ...... 460.288 339.070
Evaporation Loss ......... 64.370 47.418
Infiltration Loss ........ 149.852 110.388
Surface Runoff ........... 217.862 160.488
LID Drainage ............. 32.164 23.694
Final Storage ............ 0.017 0.012
Continuity Error (%) ..... -0.860
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 250.026 81.475
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 249.978 81.459
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.019
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 15.00 sec
Average Time Step : 15.00 sec
Maximum Time Step : 15.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 1.00
Percent Not Converging : 0.00
***************************
Subcatchment Runoff Summary
***************************
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
DMA1 339.07 0.00 64.77 95.29 188.48 5.82 183.70 12.42 2.68 0.542
DMA3 339.07 0.00 44.29 113.11 178.91 5.36 184.27 69.05 14.42 0.543
***********************
LID Performance Summary
***********************
--------------------------------------------------------------------------------------------------------------------
Total Evap Infil Surface Drain Initial Final Continuity
Inflow Loss Loss Outflow Outflow Storage Storage Error
Subcatchment LID Control in in in in in in in %
--------------------------------------------------------------------------------------------------------------------
DMA1 BMP1 6180.55 658.30 0.00 862.45 4660.03 2.40 2.40 -0.00
******************
Node Depth Summary
******************
---------------------------------------------------------------------------------
Average Maximum Maximum Time of Max Reported
Depth Depth HGL Occurrence Max Depth
Node Type Feet Feet Feet days hr:min Feet
---------------------------------------------------------------------------------
J1 JUNCTION 0.01 0.59 1.59 5532 14:01 0.59
J2 JUNCTION 0.00 0.36 2.36 4532 12:01 0.36
POC1 OUTFALL 0.01 0.59 0.59 5532 14:01 0.59
SU1 STORAGE 0.00 0.64 0.64 4532 12:01 0.64
SU2 STORAGE 0.07 4.91 4.91 5532 14:01 4.91
*******************
Node Inflow Summary
*******************
-------------------------------------------------------------------------------------------------
Maximum Maximum Lateral Total Flow
Lateral Total Time of Max Inflow Inflow Balance
Inflow Inflow Occurrence Volume Volume Error
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent
-------------------------------------------------------------------------------------------------
J1 JUNCTION 0.00 7.99 5532 14:01 0 71 0.000
J2 JUNCTION 0.00 2.56 4532 12:01 0 1.94 0.000
POC1 OUTFALL 0.04 8.03 5532 14:01 10.5 81.5 0.000
SU1 STORAGE 2.65 2.65 4532 12:00 1.94 1.94 0.000
SU2 STORAGE 14.42 14.42 4532 12:00 69 69 0.000
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------------------
Average Avg Evap Exfil Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------------------
SU1 0.020 1 0 0 3.173 85 4532 12:01 2.56
SU2 0.556 1 0 0 56.348 98 5532 14:01 6.65
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10^6 gal
-----------------------------------------------------------
POC1 8.37 0.11 8.03 81.453
-----------------------------------------------------------
System 8.37 0.11 8.03 81.453
********************
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
-----------------------------------------------------------------------------
C1 CONDUIT 7.99 5532 14:01 8.13 0.08 0.20
C2 CONDUIT 2.56 4532 12:01 5.96 0.04 0.14
OR1 ORIFICE 0.28 5532 14:01 0.00
OR2 ORIFICE 0.01 4532 12:01 0.00
W1 WEIR 6.37 5532 14:01 0.00
W2 WEIR 2.55 4532 12:01 0.00
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Tue Jun 21 14:31:26 2022
Analysis ended on: Tue Jun 21 14:32:43 2022
Total elapsed time: 00:01:17
EPA STORM WATER MANAGEMENT MODEL - VERSION 5.1 (Build 5.1.015)
--------------------------------------------------------------
Post Condition POC 2-DMA 2
*********************************************************
NOTE: The summary statistics displayed in this report are
based on results found at every computational time step,
not just on results from each reporting time step.
*********************************************************
****************
Analysis Options
****************
Flow Units ............... CFS
Process Models:
Rainfall/Runoff ........ YES
RDII ................... NO
Snowmelt ............... NO
Groundwater ............ NO
Flow Routing ........... YES
Ponding Allowed ........ NO
Water Quality .......... NO
Infiltration Method ...... GREEN_AMPT
Flow Routing Method ...... KINWAVE
Starting Date ............ 10/03/1970 05:00:00
Ending Date .............. 05/25/2008 22:00:00
Antecedent Dry Days ...... 0.0
Report Time Step ......... 01:00:00
Wet Time Step ............ 00:15:00
Dry Time Step ............ 00:15:00
Routing Time Step ........ 15.00 sec
************************** Volume Depth
Runoff Quantity Continuity acre-feet inches
************************** --------- -------
Initial LID Storage ...... 0.021 0.062
Total Precipitation ...... 113.306 339.070
Evaporation Loss ......... 18.245 54.599
Infiltration Loss ........ 43.736 130.881
Surface Runoff ........... 6.230 18.643
LID Drainage ............. 46.227 138.336
Final Storage ............ 0.021 0.062
Continuity Error (%) ..... -1.000
************************** Volume Volume
Flow Routing Continuity acre-feet 10^6 gal
************************** --------- ---------
Dry Weather Inflow ....... 0.000 0.000
Wet Weather Inflow ....... 52.457 17.094
Groundwater Inflow ....... 0.000 0.000
RDII Inflow .............. 0.000 0.000
External Inflow .......... 0.000 0.000
External Outflow ......... 52.457 17.094
Flooding Loss ............ 0.000 0.000
Evaporation Loss ......... 0.000 0.000
Exfiltration Loss ........ 0.000 0.000
Initial Stored Volume .... 0.000 0.000
Final Stored Volume ...... 0.000 0.000
Continuity Error (%) ..... 0.000
********************************
Highest Flow Instability Indexes
********************************
All links are stable.
*************************
Routing Time Step Summary
*************************
Minimum Time Step : 15.00 sec
Average Time Step : 15.00 sec
Maximum Time Step : 15.00 sec
Percent in Steady State : 0.00
Average Iterations per Step : 1.00
Percent Not Converging : 0.00
***************************
Subcatchment Runoff Summary
***************************
------------------------------------------------------------------------------------------------------------------------------
Total Total Total Total Imperv Perv Total Total Peak Runoff
Precip Runon Evap Infil Runoff Runoff Runoff Runoff Runoff Coeff
Subcatchment in in in in in in in 10^6 gal CFS
------------------------------------------------------------------------------------------------------------------------------
DMA2 339.07 0.00 54.60 130.88 158.40 6.91 156.98 17.09 4.25 0.463
***********************
LID Performance Summary
***********************
--------------------------------------------------------------------------------------------------------------------
Total Evap Infil Surface Drain Initial Final Continuity
Inflow Loss Loss Outflow Outflow Storage Storage Error
Subcatchment LID Control in in in in in in in %
--------------------------------------------------------------------------------------------------------------------
DMA2 BMP2 6723.76 661.32 0.00 720.02 5342.66 2.40 2.40 -0.00
******************
Node Depth Summary
******************
---------------------------------------------------------------------------------
Average Maximum Maximum Time of Max Reported
Depth Depth HGL Occurrence Max Depth
Node Type Feet Feet Feet days hr:min Feet
---------------------------------------------------------------------------------
POC2 OUTFALL 0.00 0.00 0.00 0 00:00 0.00
SU1 STORAGE 0.00 1.16 1.16 4532 12:05 1.11
*******************
Node Inflow Summary
*******************
-------------------------------------------------------------------------------------------------
Maximum Maximum Lateral Total Flow
Lateral Total Time of Max Inflow Inflow Balance
Inflow Inflow Occurrence Volume Volume Error
Node Type CFS CFS days hr:min 10^6 gal 10^6 gal Percent
-------------------------------------------------------------------------------------------------
POC2 OUTFALL 0.05 3.28 4532 12:05 15.1 17.1 0.000
SU1 STORAGE 4.20 4.20 4532 12:00 2.03 2.03 0.004
*********************
Node Flooding Summary
*********************
No nodes were flooded.
**********************
Storage Volume Summary
**********************
--------------------------------------------------------------------------------------------------
Average Avg Evap Exfil Maximum Max Time of Max Maximum
Volume Pcnt Pcnt Pcnt Volume Pcnt Occurrence Outflow
Storage Unit 1000 ft3 Full Loss Loss 1000 ft3 Full days hr:min CFS
--------------------------------------------------------------------------------------------------
SU1 0.022 0 0 0 6.178 92 4532 12:05 3.23
***********************
Outfall Loading Summary
***********************
-----------------------------------------------------------
Flow Avg Max Total
Freq Flow Flow Volume
Outfall Node Pcnt CFS CFS 10^6 gal
-----------------------------------------------------------
POC2 7.80 0.02 3.28 17.093
-----------------------------------------------------------
System 7.80 0.02 3.28 17.093
********************
Link Flow Summary
********************
-----------------------------------------------------------------------------
Maximum Time of Max Maximum Max/ Max/
|Flow| Occurrence |Veloc| Full Full
Link Type CFS days hr:min ft/sec Flow Depth
-----------------------------------------------------------------------------
OR2 ORIFICE 0.03 4532 12:05 0.00
W1 WEIR 3.20 4532 12:05 0.00
*************************
Conduit Surcharge Summary
*************************
No conduits were surcharged.
Analysis begun on: Wed Jun 22 08:12:37 2022
Analysis ended on: Wed Jun 22 08:13:14 2022
Total elapsed time: 00:00:37
ATTACHMENT E
Flow Frequency Statistical Analysis
Pre-project Flow Frequency - Long-term Simulation
Statistics - Node POC1 Total Inflow
Event Event Exceedance Return
Duration Peak Frequency Period
Rank Start Date (hours) (CFS) (percent) (years) (years)
1 3/1/1983 30 14.967 1.28 39 10-year Q:5.760 cfs
2 11/25/1985 16 6.514 2.56 19.5 5-year Q:4.477 cfs
3 1/11/2005 5 6.181 3.85 13 2-year Q:3.263 cfs
4 3/24/1983 2 5.725 5.13 9.75
5 12/21/1970 2 5.455 6.41 7.8
6 1/16/1978 3 5.273 7.69 6.5 Lower Flow Threshold:10%
7 10/19/2004 32 4.864 8.97 5.57
8 11/11/1972 1 4.395 10.26 4.88 0.1xQ2 0.326 cfs
9 2/21/2005 3 4.356 11.54 4.33
10 1/3/2005 21 4.278 12.82 3.9
11 2/28/1991 11 3.908 14.1 3.55
12 3/27/1991 2 3.885 15.38 3.25
13 8/16/1977 6 3.828 16.67 3
14 4/1/1982 2 3.796 17.95 2.79
15 2/22/2004 5 3.767 19.23 2.6
16 3/2/2004 2 3.642 20.51 2.44
17 1/31/1979 11 3.461 21.79 2.29
18 3/19/1983 1 3.4 23.08 2.17
19 12/7/1992 3 3.394 24.36 2.05
20 2/19/1993 2 3.131 25.64 1.95
21 1/29/1980 5 2.95 26.92 1.86
22 11/29/1970 3 2.83 28.21 1.77
23 2/23/2005 1 2.468 29.49 1.7
24 1/4/1995 5 2.446 30.77 1.63
25 12/27/1984 22 2.357 32.05 1.56
26 3/1/1978 1 2.313 33.33 1.5
27 3/6/1980 5 2.261 34.62 1.44
28 4/28/1994 2 2.205 35.9 1.39
29 3/1/1981 10 2.032 37.18 1.34
30 1/15/1993 19 1.886 38.46 1.3
31 3/2/1992 4 1.836 39.74 1.26
32 12/4/1992 1 1.802 41.03 1.22
33 3/10/1975 2 1.628 42.31 1.18
34 3/17/1982 9 1.571 43.59 1.15
35 2/6/1992 4 1.466 44.87 1.11
36 3/21/1983 1 1.453 46.15 1.08
37 11/10/1982 1 1.284 47.44 1.05
38 12/7/1986 1 1.23 48.72 1.03
39 3/7/1992 1 1.203 50 1
40 9/10/1976 14 1.182 51.28 0.98
41 2/10/1978 2 1.175 52.56 0.95
42 11/12/1976 1 1.167 53.85 0.93
43 2/20/1980 21 1.162 55.13 0.91
44 10/10/1986 4 1.088 56.41 0.89
45 12/29/1977 1 1.066 57.69 0.87
46 3/7/1974 1 1.04 58.97 0.85
47 8/14/1983 1 1.024 60.26 0.83
48 1/25/1995 2 0.971 61.54 0.81
49 1/12/1993 3 0.935 62.82 0.8
50 1/29/1983 2 0.896 64.1 0.78
51 12/11/1984 4 0.864 65.38 0.76
52 3/5/2000 1 0.724 66.67 0.75
53 3/16/1986 1 0.672 67.95 0.74
54 2/26/1987 1 0.562 69.23 0.72
55 10/11/1987 1 0.53 70.51 0.71
56 2/26/2004 1 0.529 71.79 0.7
57 10/23/1976 1 0.511 73.08 0.68
58 3/20/1973 1 0.481 74.36 0.67
59 1/1/1982 2 0.454 75.64 0.66
60 10/30/1998 1 0.438 76.92 0.65
61 2/8/1976 5 0.405 78.21 0.64
62 2/14/1995 1 0.398 79.49 0.63
63 3/20/1991 1 0.396 80.77 0.62
64 2/2/1988 2 0.394 82.05 0.61
65 11/14/1978 1 0.377 83.33 0.6
66 3/5/1978 1 0.373 84.62 0.59
69 12/19/1970 1 0.321 88.46 0.57
69 1/6/1993 17 0.321 88.46 0.57
69 1/7/1974 25 0.321 88.46 0.57
70 3/11/1978 3 0.32 89.74 0.56
71 4/29/1980 1 0.286 91.03 0.55
72 11/22/1984 1 0.207 92.31 0.54
73 1/15/1978 1 0.202 93.59 0.53
74 1/4/1974 1 0.137 94.87 0.53
75 2/2/1983 1 0.083 96.15 0.52
Post-project Flow Frequency - Long-term Simulation
Statistics - Node POC1 Total Inflow
Event Event Exceedance Return
Duration Peak Frequency Period
Rank Start Date (hours) (CFS) (percent) (years)
1 3/1/1983 30 14.961 1.28 39 10-year Q:5.804 cfs
2 11/25/1985 16 6.548 2.56 19.5 5-year Q:4.516 cfs
3 1/11/2005 5 6.206 3.85 13 2-year Q:3.274 cfs
4 3/24/1983 2 5.771 5.13 9.75
5 12/21/1970 2 5.485 6.41 7.8
6 1/16/1978 3 5.272 7.69 6.5 Lower Flow Threshold:10%
7 10/19/2004 32 4.903 8.97 5.57
8 11/11/1972 1 4.434 10.26 4.88 0.1xQ2: 0.327 cfs
9 2/21/2005 3 4.346 11.54 4.33
10 1/3/2005 21 4.297 12.82 3.9
11 2/28/1991 11 3.944 14.1 3.55
12 3/27/1991 2 3.905 15.38 3.25
13 8/16/1977 6 3.844 16.67 3
14 4/1/1982 2 3.828 17.95 2.79
15 2/22/2004 5 3.793 19.23 2.6
16 3/2/2004 2 3.674 20.51 2.44
17 1/31/1979 11 3.465 21.79 2.29
18 3/19/1983 1 3.431 23.08 2.17
19 12/7/1992 3 3.385 24.36 2.05
20 2/19/1993 2 3.162 25.64 1.95
21 1/29/1980 5 2.948 26.92 1.86
22 11/29/1970 3 2.834 28.21 1.77
23 2/23/2005 1 2.492 29.49 1.7
24 1/4/1995 5 2.45 30.77 1.63
25 12/27/1984 22 2.375 32.05 1.56
26 3/1/1978 1 2.33 33.33 1.5
27 3/6/1980 5 2.256 34.62 1.44
28 4/28/1994 2 2.228 35.9 1.39
29 3/1/1981 10 2.053 37.18 1.34
30 1/15/1993 19 1.89 38.46 1.3
31 3/2/1992 4 1.856 39.74 1.26
32 12/4/1992 1 1.819 41.03 1.22
33 3/10/1975 2 1.635 42.31 1.18
34 3/17/1982 9 1.585 43.59 1.15
35 2/6/1992 4 1.471 44.87 1.11
36 3/21/1983 1 1.467 46.15 1.08
37 11/10/1982 1 1.298 47.44 1.05
38 12/7/1986 1 1.243 48.72 1.03
39 3/7/1992 1 1.216 50 1
40 9/10/1976 14 1.194 51.28 0.98
41 2/10/1978 2 1.184 52.56 0.95
42 11/12/1976 1 1.177 53.85 0.93
43 2/20/1980 21 1.173 55.13 0.91
44 10/10/1986 4 1.099 56.41 0.89
45 12/29/1977 1 1.077 57.69 0.87
46 3/7/1974 1 1.05 58.97 0.85
47 8/14/1983 1 1.031 60.26 0.83
48 1/25/1995 2 0.977 61.54 0.81
49 1/12/1993 3 0.94 62.82 0.8
50 1/29/1983 2 0.905 64.1 0.78
51 12/11/1984 4 0.868 65.38 0.76
52 3/5/2000 1 0.731 66.67 0.75
53 3/16/1986 1 0.677 67.95 0.74
54 2/26/1987 1 0.568 69.23 0.72
55 2/26/2004 1 0.534 70.51 0.71
56 10/11/1987 1 0.533 71.79 0.7
57 10/23/1976 1 0.514 73.08 0.68
58 3/20/1973 1 0.484 74.36 0.67
59 1/1/1982 2 0.457 75.64 0.66
60 10/30/1998 1 0.44 76.92 0.65
61 2/8/1976 5 0.407 78.21 0.64
62 2/14/1995 1 0.402 79.49 0.63
63 3/20/1991 1 0.397 80.77 0.62
64 2/2/1988 2 0.396 82.05 0.61
65 11/14/1978 1 0.38 83.33 0.6
66 3/5/1978 1 0.377 84.62 0.59
67 3/11/1978 3 0.324 85.9 0.58
70 12/19/1970 1 0.323 89.74 0.56
70 1/7/1974 25 0.323 89.74 0.56
70 1/6/1993 17 0.323 89.74 0.56
71 4/29/1980 1 0.287 91.03 0.55
72 11/22/1984 1 0.208 92.31 0.54
73 1/15/1978 1 0.204 93.59 0.53
74 1/4/1974 1 0.137 94.87 0.53
75 2/2/1983 1 0.084 96.15 0.52
Pre-project Flow Frequency - Long-term Simulation
DMA 2 POC 2
Statistics - Node POC2 Total Inflow
Event Event Exceedance Return
Duration Peak Frequency Period
Rank Start Date (hours) (CFS) (percent) (years) (years)
1 3/1/1983 31 3.562 1.32 39 10-year Q:1.276 cfs
2 11/25/1985 16 1.486 2.63 19.5 5-year Q:1.054 cfs
3 1/11/2005 5 1.423 3.95 13 2-year Q:0.720 cfs
4 3/24/1983 2 1.264 5.26 9.75
5 1/16/1978 3 1.252 6.58 7.8
6 12/21/1970 2 1.243 7.89 6.5 Lower Flow Threshold:10%
7 10/19/2004 32 1.075 9.21 5.57
8 2/21/2005 3 1.049 10.53 4.88 0.1xQ2: 0.072 cfs
9 1/3/2005 21 0.982 11.84 4.33
10 11/11/1972 1 0.958 13.16 3.9
11 3/27/1991 2 0.886 14.47 3.55
12 8/16/1977 6 0.877 15.79 3.25
13 2/28/1991 11 0.849 17.11 3
14 2/22/2004 5 0.845 18.42 2.79
15 4/1/1982 2 0.833 19.74 2.6
16 12/7/1992 3 0.816 21.05 2.44
17 1/31/1979 11 0.809 22.37 2.29
18 3/2/2004 2 0.797 23.68 2.17
19 3/19/1983 1 0.739 25 2.05
20 1/29/1980 5 0.701 26.32 1.95
21 2/19/1993 2 0.67 27.63 1.86
22 11/29/1970 3 0.663 28.95 1.77
23 1/4/1995 5 0.571 30.26 1.7
24 3/6/1980 5 0.543 31.58 1.63
25 2/23/2005 1 0.527 32.89 1.56
26 12/27/1984 23 0.526 34.21 1.5
27 3/1/1978 1 0.515 35.53 1.44
28 4/28/1994 2 0.463 36.84 1.39
29 1/15/1993 19 0.441 38.16 1.34
30 3/1/1981 10 0.423 39.47 1.3
31 3/2/1992 4 0.379 40.79 1.26
32 3/10/1975 2 0.372 42.11 1.22
33 12/4/1992 1 0.354 43.42 1.18
34 3/17/1982 9 0.343 44.74 1.15
35 2/6/1992 4 0.34 46.05 1.11
36 3/21/1983 1 0.286 47.37 1.08
37 2/10/1978 2 0.263 48.68 1.05
38 11/10/1982 1 0.259 50 1.03
39 12/7/1986 1 0.246 51.32 1
40 3/7/1992 1 0.24 52.63 0.98
41 9/10/1976 14 0.236 53.95 0.95
42 2/20/1980 21 0.234 55.26 0.93
43 11/12/1976 1 0.226 56.58 0.91
44 1/25/1995 2 0.221 57.89 0.89
45 10/10/1986 4 0.215 59.21 0.87
46 12/29/1977 1 0.211 60.53 0.85
47 1/12/1993 3 0.209 61.84 0.83
48 3/7/1974 1 0.205 63.16 0.81
49 12/11/1984 4 0.194 64.47 0.8
50 8/14/1983 1 0.191 65.79 0.78
51 1/29/1983 2 0.174 67.11 0.76
52 3/5/2000 1 0.139 68.42 0.75
53 3/16/1986 1 0.127 69.74 0.74
54 2/26/1987 1 0.113 71.05 0.72
55 2/26/2004 1 0.101 72.37 0.71
56 10/11/1987 1 0.097 73.68 0.7
57 10/23/1976 1 0.095 75 0.68
58 2/8/1976 5 0.09 76.32 0.67
59 3/20/1973 1 0.089 77.63 0.66
60 1/1/1982 2 0.085 78.95 0.65
61 10/30/1998 1 0.08 80.26 0.64
62 2/14/1995 1 0.078 81.58 0.63
63 3/5/1978 1 0.077 82.89 0.62
64 2/2/1988 2 0.072 84.21 0.61
65 3/20/1991 1 0.072 85.53 0.6
66 11/14/1978 1 0.072 86.84 0.59
67 3/11/1978 3 0.067 88.16 0.58
70 12/19/1970 1 0.059 92.11 0.56
70 1/6/1993 17 0.059 92.11 0.56
70 1/7/1974 25 0.059 92.11 0.56
71 4/29/1980 1 0.052 93.42 0.55
72 1/15/1978 1 0.038 94.74 0.54
73 11/22/1984 1 0.037 96.05 0.53
74 1/4/1974 1 0.024 97.37 0.53
75 2/2/1983 1 0.016 98.68 0.52
Post-project Flow Frequency - Long-term Simulation
DMA 2 POC 2
Statistics - Node POC2 Total Inflow
Event Event Exceedance Return
Duration Peak Frequency Period
Rank Start Date (hours) (CFS) (percent) (years)
1 11/24/1985 160 2.06 0.26 39 10-year Q:1.257 cfs
2 2/24/1983 264 1.541 0.53 19.5 5-year Q:0.945 cfs
3 12/4/1992 159 1.267 0.79 13 2-year Q:0.277 cfs
4 1/31/1979 122 1.256 1.06 9.75
5 2/18/2005 195 1.172 1.32 7.8
6 2/21/2004 156 1.083 1.58 6.5 Lower Flow Threshold:10%
7 10/17/2004 165 0.958 1.85 5.57
8 2/27/1991 117 0.942 2.11 4.88 0.1xQ2: 0.028 cfs
9 1/28/1980 122 0.917 2.37 4.33
10 1/3/2005 268 0.647 2.64 3.9
11 1/14/1978 159 0.563 2.9 3.55
12 1/12/1993 204 0.548 3.17 3.25
13 12/28/2004 113 0.533 3.43 3
14 3/14/1982 161 0.524 3.69 2.79
15 1/3/1995 145 0.377 3.96 2.6
16 1/6/1993 133 0.364 4.22 2.44
17 2/4/1976 224 0.339 4.49 2.29
18 12/17/1970 182 0.278 4.75 2.17
19 12/27/1984 101 0.277 5.01 2.05
20 2/6/1992 256 0.077 5.28 1.95
21 3/2/1992 87 0.073 5.54 1.86
22 3/6/1980 78 0.072 5.8 1.77
23 2/27/1978 193 0.072 6.07 1.7
24 8/16/1977 83 0.071 6.33 1.63
25 3/25/1991 119 0.071 6.6 1.56
26 11/11/1985 86 0.07 6.86 1.5
27 11/10/1972 158 0.07 7.12 1.44
28 3/4/2005 75 0.07 7.39 1.39
29 3/15/2003 81 0.068 7.65 1.34
30 2/15/1986 78 0.068 7.92 1.3
31 3/19/1991 126 0.068 8.18 1.26
32 12/16/1987 115 0.067 8.44 1.22
33 3/5/1995 85 0.066 8.71 1.18
34 10/27/2004 79 0.065 8.97 1.15
35 12/10/1984 86 0.064 9.23 1.11
36 2/19/2007 118 0.064 9.5 1.08
37 2/14/1995 84 0.064 9.76 1.05
38 11/21/1996 78 0.064 10.03 1.03
39 11/12/1976 72 0.063 10.29 1
40 3/17/1983 241 0.063 10.55 0.98
41 2/28/1981 181 0.062 10.82 0.95
42 1/24/1995 111 0.059 11.08 0.93
43 2/2/1988 81 0.059 11.35 0.91
44 1/25/1999 105 0.058 11.61 0.89
45 11/29/1970 72 0.057 11.87 0.87
46 3/6/1975 208 0.055 12.14 0.85
47 2/18/1993 215 0.054 12.4 0.83
48 1/5/1979 75 0.054 12.66 0.81
49 8/14/1983 127 0.05 12.93 0.8
50 11/30/2007 74 0.05 13.19 0.78
51 12/17/1978 118 0.05 13.46 0.76
52 1/20/1982 81 0.05 13.72 0.75
53 12/6/1986 98 0.05 13.98 0.74
54 2/19/1980 106 0.05 14.25 0.72
55 3/20/1973 69 0.05 14.51 0.71
56 11/9/1982 82 0.05 14.78 0.7
57 1/5/2008 109 0.05 15.04 0.68
58 1/5/1987 92 0.05 15.3 0.67
59 2/2/1983 84 0.05 15.57 0.66
60 2/11/2005 98 0.049 15.83 0.65
61 12/4/1972 128 0.049 16.09 0.64
62 3/10/1980 65 0.049 16.36 0.63
63 5/8/1977 70 0.049 16.62 0.62
64 12/25/1988 83 0.049 16.89 0.61
65 4/1/1982 62 0.049 17.15 0.6
66 2/24/1987 102 0.049 17.41 0.59
67 3/11/1995 76 0.048 17.68 0.58
68 10/9/1986 66 0.048 17.94 0.57
69 3/2/2004 58 0.048 18.21 0.57
70 10/11/1987 81 0.048 18.47 0.56
71 9/25/1986 58 0.048 18.73 0.55
72 9/10/1976 72 0.048 19 0.54
73 1/4/1974 159 0.048 19.26 0.53
74 1/5/1992 88 0.048 19.53 0.53
75 1/12/1997 110 0.048 19.79 0.52
ATTACHMENT F
Flow Duration Comparison Curve
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 3
Structural BMP Maintenance Information
Hydromodification Control Measures
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Use this checklist to ensure the required information has been included in the
Structural BMP Maintenance Information Attachment:
Attachment 3: For private entity operation and maintenance, Attachment 3 must include a Storm
Water Management Facilities Maintenance Agreement with Grant of Access and Covenant’s
(“Maintenance Agreement”) Template can be found at the following link (also refer to Chapter 8.2.1
for more information’s):
The following information must be included in the exhibits attached to the Maintenance Agreement:
Vicinity map (Depiction of Project Site)
Legal Description for Project Site
Site design BMPs for which DCV reduction is claimed for meeting the pollutant
control obligations.
BMP and HMP type, location, type, manufacture model, and dimensions, specifications,
cross section
LID features such as (permeable paver and LS location, dim, SF).
Maintenance recommendations and frequency
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Inspection Guidelines for
Modular Wetland System - Linear
Inspection Summary
o Inspect Pre-Treatment, Biofiltration and Discharge Chambers – average inspection interval is 6 to
12 months.
(15 minute average inspection time).
o NOTE: Pollutant loading varies greatly from site to site and no two sites are the same. Therefore,
the first year requires inspection monthly during the wet season and every other month during the
dry season in order to observe and record the amount of pollutant loading the system is receiving.
System Diagram
Access to separation chamber and pre-filter cartridges
1 Pre-treatment Chamber
2 Biofiltration Chamber
3 Discharge Chamber
Access to discharge chamber and orifice control
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Inspection Overview
As with all stormwater BMPs inspection and maintenance on the MWS Linear is necessary.
Stormwater regulations require that all BMPs be inspected and maintained to ensure they are
operating as designed to allow for effective pollutant removal and provide protection to receiving water
bodies. It is recommended that inspections be performed multiple times during the first year to assess
the site specific loading conditions. This is recommended because pollutant loading and pollutant
characteristics can vary greatly from site to site. Variables such as nearby soil erosion or construction
sites, winter sanding on roads, amount of daily traffic and land use can increase pollutant loading on
the system. The first year of inspections can be used to set inspection and maintenance intervals for
subsequent years to ensure appropriate maintenance is provided. Without appropriate maintenance a
BMP will exceed its storage capacity which can negatively affect its continued performance in
removing and retaining captured pollutants.
Inspection Equipment
Following is a list of equipment to allow for simple and effective inspection of the MWS Linear:
Modular Wetland Inspection Form
Flashlight
Manhole hook or appropriate tools to remove access hatches and covers
Appropriate traffic control signage and procedures
Measuring pole and/or tape measure.
Protective clothing and eye protection.
7/16” open or closed ended wrench.
Large permanent black marker (initial inspections only – first year)
Note: entering a confined space requires appropriate safety and certification. It is generally not
required for routine inspections of the system.
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Inspection Steps
The core to any successful stormwater BMP maintenance program is routine inspections. The
inspection steps required on the MWS Linear are quick and easy. As mentioned above the first year
should be seen as the maintenance interval establishment phase. During the first year more frequent
inspections should occur in order to gather loading data and maintenance requirements for that
specific site. This information can be used to establish a base for long term inspection and
maintenance interval requirements.
The MWS Linear can be inspected though visual observation without entry into the system. All
necessary pre-inspection steps must be carried out before inspection occurs, especially traffic control
and other safety measures to protect the inspector and near-by pedestrians from any dangers
associated with an open access hatch or manhole. Once these access covers have been safely
opened the inspection process can proceed:
Prepare the inspection form by writing in the necessary information including project name,
location, date & time, unit number and other info (see inspection form).
Observe the inside of the system through the access hatches. If minimal light is available and
vision into the unit is impaired utilize a flashlight to see inside the system and all of its
chambers.
Look for any out of the ordinary obstructions in the inflow pipe, pre-treatment chamber,
biofiltration chamber, discharge chamber or outflow pipe. Write down any observations on the
inspection form.
Through observation and/or digital photographs estimate the amount of trash, debris and
sediment accumulated in the pre-treatment chamber. Utilizing a tape measure or measuring
stick estimate the amount of trash, debris and sediment in this chamber. Record this depth on
the inspection form.
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Through visual observation inspect the condition of the pre-filter cartridges. Look for excessive
build-up of sediments on the cartridges, any build-up on the top of the cartridges, or clogging
of the holes. Record this information on the inspection form. The pre-filter cartridges can
further be inspected by removing the cartridge tops and assessing the color of the
BioMediaGREEN filter cubes (requires entry into pre-treatment chamber – see notes above
regarding confined space entry). Record the color of the material. New material is a light green
in color. As the media becomes clogged it will turn darker in color, eventually becoming dark
brown or black. Using the below color indicator record the percentage of media exhausted.
The biofiltration chamber is generally maintenance free due to the system’s advanced pre-
treatment chamber. For units which have open planters with vegetation it is recommended that
the vegetation be inspected. Look for any plants that are dead or showing signs of disease or
other negative stressors. Record the general health of the plants on the inspection and
indicate through visual observation or digital photographs if trimming of the vegetation is
needed.
The discharge chamber houses the orifice control structure and is connected to the outflow
pipe. It is important to check to ensure the orifice is in proper operating conditions and free of
any obstructions. Generally, the discharge chamber will be clean and free of debris. Inspect
the water marks on the side walls. If possible, inspect the discharge chamber during a rain
event to assess the amount of flow leaving the system while it is at 100% capacity (pre-
treatment chamber water level at peak HGL). The water level of the flowing water should be
compared to the watermark level on the side walls which is an indicator of the highest
discharge rate the system achieved when initially installed. Record on the form is there is any
difference in level from watermark in inches.
0% -- Percent Clogged -- 100%
New
BioMediaGREEN
Exhausted
BioMediaGREEN
85%
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NOTE: During the first few storms the water level in the outflow chamber should be observed
and a 6” long horizontal watermark line drawn (using a large permanent marker) at the water
level in the discharge chamber while the system is operating at 100% capacity. The diagram
below illustrates where a line should be drawn. This line is a reference point for future
inspections of the system:
Water level in the discharge chamber is a function of flow rate and pipe size. Observation of
water level during the first few months of operation can be used as a benchmark level for
future inspections. The initial mark and all future observations shall be made when system is
at 100% capacity (water level at maximum level in pre-treatment chamber). If future water
levels are below this mark when system is at 100% capacity this is an indicator that
maintenance to the pre-filter cartridges may be needed.
Finalize inspection report for analysis by the maintenance manager to determine if
maintenance is required.
Water Level
Mark
Water Level
Marks
Using a permanent marker draw a 6 inch long horizontal line, as shown, at the
higher water level in the MWS Linear discharge chamber.
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Maintenance Indicators
Based upon observations made during inspection, maintenance of the system may be required based
on the following indicators:
Missing or damaged internal components or cartridges.
Obstructions in the system or its inlet or outlet.
Excessive accumulation of floatables in the pre-treatment chamber in which the length and
width of the chamber is fully impacted more than 18”.
Excessive accumulation of sediment in the pre-treatment chamber of more than 6” in depth.
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Excessive accumulation of sediment on the BioMediaGREEN media housed within the pre-
filter cartridges. The following chart shows photos of the condition of the BioMediaGREEN
contained within the pre-filter cartridges. When media is more than 85% clogged replacement
is required.
Overgrown vegetation.
Water level in discharge chamber during 100% operating capacity (pre-treatment chamber
water level at max height) is lower than the watermark by 20%.
0% -- Percent Clogged -- 100%
New
BioMediaGREEN
Exhausted
BioMediaGREEN
85%
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Inspection Notes
1. Following maintenance and/or inspection, it is recommended the maintenance operator
prepare a maintenance/inspection record. The record should include any maintenance
activities performed, amount and description of debris collected, and condition of the
system and its various filter mechanisms.
2. The owner should keep maintenance/inspection record(s) for a minimum of five years from
the date of maintenance. These records should be made available to the governing
municipality for inspection upon request at any time.
3. Transport all debris, trash, organics and sediments to approved facility for disposal in
accordance with local and state requirements.
4. Entry into chambers may require confined space training based on state and local
regulations.
5. No fertilizer shall be used in the Biofiltration Chamber.
6. Irrigation should be provided as recommended by manufacturer and/or landscape
architect. Amount of irrigation required is dependent on plant species. Some plants may
not require irrigation after initial establishment.
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Maintenance Guidelines for
Modular Wetland System - Linear
Maintenance Summary
o Remove Sediment from Pre-Treatment Chamber – average maintenance interval is 12 to 24
months.
(10 minute average service time).
o Replace Pre-Filter Cartridge Media – average maintenance interval 12 to 24 months.
(10-15 minute per cartridge average service time).
o Trim Vegetation – average maintenance interval is 6 to 12 months.
(Service time varies).
System Diagram
Access to separation chamber and pre-filter cartridge
1 Pre-treatment Chamber
2 Biofiltration Chamber
3 Discharge Chamber
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Maintenance Overview
The time has come to maintain your Modular Wetland System Linear (MWS Linear). To ensure
successful and efficient maintenance on the system we recommend the following. The MWS Linear
can be maintained by removing the access hatches over the systems various chambers. All
necessary pre-maintenance steps must be carried out before maintenance occurs, especially traffic
control and other safety measures to protect the inspector and near-by pedestrians from any dangers
associated with an open access hatch or manhole. Once traffic control has been set up per local and
state regulations and access covers have been safely opened the maintenance process can begin. It
should be noted that some maintenance activities require confined space entry. All confined space
requirements must be strictly followed before entry into the system. In addition the following is
recommended:
Prepare the maintenance form by writing in the necessary information including project name,
location, date & time, unit number and other info (see maintenance form).
Set up all appropriate safety and cleaning equipment.
Ensure traffic control is set up and properly positioned.
Prepare a pre-checks (OSHA, safety, confined space entry) are performed.
Maintenance Equipment
Following is a list of equipment required for maintenance of the MWS Linear:
Modular Wetland Maintenance Form
Manhole hook or appropriate tools to access hatches and covers
Protective clothing, flashlight and eye protection.
7/16” open or closed ended wrench.
Vacuum assisted truck with pressure washer.
Replacement BioMediaGREEN for Pre-Filter Cartridges if required (order from manufacturer).
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Maintenance Steps
1. Pre-treatment Chamber (bottom of chamber)
A. Remove access hatch or manhole cover over pre-treatment chamber and position vacuum
truck accordingly.
B. With a pressure washer spray down pollutants accumulated on walls and pre-filter
cartridges.
C. Vacuum out Pre-Treatment Chamber and remove all accumulated pollutants including
trash, debris and sediments. Be sure to vacuum the floor until pervious pavers are visible
and clean.
D. If Pre-Filter Cartridges require media replacement move onto step 2. If not, replace access
hatch or manhole cover.
Removal of access hatch to gain access below. Insertion of vacuum hose into separation chamber.
Removal of trash, sediment and debris. Fully cleaned separation chamber.
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2. Pre-Filter Cartridges (attached to wall of pre-treatment chamber)
A. After finishing step 1 enter pre-treatment chamber.
B. Unscrew the two bolts holding the lid on each cartridge filter and remove lid.
C. Place the vacuum hose over each individual media filter to suck out filter media.
D. Once filter media has been sucked use a pressure washer to spray down inside of the
cartridge and it’s containing media cages. Remove cleaned media cages and place to the
side. Once removed the vacuum hose can be inserted into the cartridge to vacuum out any
remaining material near the bottom of the cartridge.
Pre-filter cartridges with tops on.
Inside cartridges showing media filters ready for
replacement.
Vacuuming out of media filters.
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E. Reinstall media cages and fill with new media from manufacturer or outside supplier.
Manufacturer will provide specification of media and sources to purchase. Utilize the
manufacture provided refilling trey and place on top of cartridge. Fill trey with new bulk
media and shake down into place. Using your hands slightly compact media into each filter
cage. Once cages are full removed refilling trey and replace cartridge top ensuring bolts
are properly tightened.
F. Exit pre-treatment chamber. Replace access hatch or manhole cover.
3. Biofiltration Chamber (middle vegetated chamber)
A. In general, the biofiltration chamber is maintenance free with the exception of maintaining
the vegetation. Using standard gardening tools properly trim back the vegetation to healthy
levels. The MWS Linear utilizes vegetation similar to surrounding landscape areas
therefore trim vegetation to match surrounding vegetation. If any plants have died replace
plants with new ones:
Refilling trey for media replacement. Refilling trey on cartridge with bulk
media.
www.modularwetlands.com
Inspection Notes
1. Following maintenance and/or inspection, it is recommended the maintenance operator
prepare a maintenance/inspection record. The record should include any maintenance
activities performed, amount and description of debris collected, and condition of the
system and its various filter mechanisms.
2. The owner should keep maintenance/inspection record(s) for a minimum of five years from
the date of maintenance. These records should be made available to the governing
municipality for inspection upon request at any time.
3. Transport all debris, trash, organics and sediments to approved facility for disposal in
accordance with local and state requirements.
4. Entry into chambers may require confined space training based on state and local
regulations.
5. No fertilizer shall be used in the Biofiltration Chamber.
6. Irrigation should be provided as recommended by manufacturer and/or landscape
architect. Amount of irrigation required is dependent on plant species. Some plants may
not require irrigation after initial establishment.
www.modularwetlands.com
Inspection Form
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. Info@modularwetlands.com
For Office Use Only
(city) (Zip Code)(Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( )_
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Yes
Depth:
Yes No
Modular Wetland System Type (Curb, Grate or UG Vault):Size (22', 14' or etc.):
Other Inspection Items:
Storm Event in Last 72-hours? No Yes Type of Inspection Routine Follow Up Complaint Storm
Office personnel to complete section to
the left.
2972 San Luis Rey Road, Oceanside, CA 92058 P (760) 433-7640 F (760) 433-3176
Inspection Report
Modular Wetlands System
Is the filter insert (if applicable) at capacity and/or is there an accumulation of debris/trash on the shelf system?
Does the cartridge filter media need replacement in pre-treatment chamber and/or discharge chamber?
Any signs of improper functioning in the discharge chamber? Note issues in comments section.
Chamber:
Is the inlet/outlet pipe or drain down pipe damaged or otherwise not functioning properly?
Structural Integrity:
Working Condition:
Is there evidence of illicit discharge or excessive oil, grease, or other automobile fluids entering and clogging the
unit?
Is there standing water in inappropriate areas after a dry period?
Damage to pre-treatment access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Damage to discharge chamber access cover (manhole cover/grate) or cannot be opened using normal lifting
pressure?
Does the MWS unit show signs of structural deterioration (cracks in the wall, damage to frame)?
Project Name
Project Address
Inspection Checklist
CommentsNo
Does the depth of sediment/trash/debris suggest a blockage of the inflow pipe, bypass or cartridge filter? If yes,
specify which one in the comments section. Note depth of accumulation in in pre-treatment chamber.
Is there a septic or foul odor coming from inside the system?
Is there an accumulation of sediment/trash/debris in the wetland media (if applicable)?
Is it evident that the plants are alive and healthy (if applicable)? Please note Plant Information below.
Sediment / Silt / Clay
Trash / Bags / Bottles
Green Waste / Leaves / Foliage
Waste:Plant Information
No Cleaning Needed
Recommended Maintenance
Additional Notes:
Damage to Plants
Plant Replacement
Plant Trimming
Schedule Maintenance as Planned
Needs Immediate Maintenance
www.modularwetlands.com
Maintenance Report
Modular Wetland System, Inc.
P. 760.433-7640
F. 760-433-3176
E. Info@modularwetlands.com
For Office Use Only
(city) (Zip Code)(Reviewed By)
Owner / Management Company
(Date)
Contact Phone ( )_
Inspector Name Date / / Time AM / PM
Weather Condition Additional Notes
Site
Map #
Comments:
2972 San Luis Rey Road, Oceanside, CA 92058 P. 760.433.7640 F. 760.433.3176
Inlet and Outlet
Pipe Condition
Drain Down Pipe
Condition
Discharge Chamber
Condition
Drain Down Media
Condition
Plant Condition
Media Filter
Condition
Long:
MWS
Sedimentation
Basin
Total Debris
Accumulation
Condition of Media
25/50/75/100
(will be changed
@ 75%)
Operational Per
Manufactures'
Specifications
(If not, why?)
Lat:MWS
Catch Basins
GPS Coordinates
of Insert
Manufacturer /
Description / Sizing
Trash
Accumulation
Foliage
Accumulation
Sediment
Accumulation
Type of Inspection Routine Follow Up Complaint Storm Storm Event in Last 72-hours? No Yes
Office personnel to complete section to
the left.
Project Address
Project Name
Cleaning and Maintenance Report
Modular Wetlands System
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 4
Copy of Plan Sheets Showing
Permanent Storm Water BMPs
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
Use this checklist to ensure the required information has been included on the
plans:
The plans must identify:
Structural BMP(s) with ID numbers matching Form I-6 Summary of PDP Structural BMPs
The grading and drainage design shown on the plans must be consistent with the delineation
of DMAs shown on the DMA exhibit
Details and specifications for construction of structural BMP(s)
Signage indicating the location and boundary of structural BMP(s) as required by the City
Engineer
How to access the structural BMP(s) to inspect and perform maintenance
Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts,
or other features that allow the inspector to view necessary components of the structural BMP
and compare to maintenance thresholds)
Manufacturer and part number for proprietary parts of structural BMP(s) when applicable
Maintenance thresholds specific to the structural BMP(s), with a location-specific frame of
reference (e.g., level of accumulated materials that triggers removal of the materials, to be
identified based on viewing marks on silt posts or measured with a survey rod with respect to
a fixed benchmark within the BMP)
Recommended equipment to perform maintenance
When applicable, necessary special training or certification requirements for inspection and
maintenance personnel such as confined space entry or hazardous waste management
Include landscaping plan sheets showing vegetation requirements for vegetated structural
BMP(s)
All BMPs must be fully dimensioned on the plans
When proprietary BMPs are used, site specific cross section with outflow, inflow and model
number shall be provided. Broucher photocopies are not allowed.
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CIVIL SENSE INC
13475 Danielson Street, Suite 150 | Poway, CA 92064
Office: 858-842-4353
No. 63686
Exp. 09-30-22
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CIVIL SENSE INC
13475 Danielson Street, Suite 150 | Poway, CA 92064
Office: 858-842-4353
No. 63686
Exp. 09-30-22
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Modular Wetlands® System Linear
A Stormwater Biofiltration Solution
A Forterra Company
85%
64% REMOVAL
OF TOTAL
PHOSPHORUS
REMOVAL
OF TSS
45%67 %
REMOVAL
OF ORTHO
PHOSPHORUS
REMOVAL
OF
NITROGEN
66%
REMOVAL
OF
DISSOLVED
ZINC
38%
REMOVAL
OF
DISSOLVED
COPPER
69 %
REMOVAL
OF TOTAL
ZINC
50%
REMOVAL
OF TOTAL
COPPER
95%
REMOVAL
OF MOTOR
OIL
OVERVIEW
The Bio Clean Modular Wetlands® System Linear represents a pioneering breakthrough in stormwater
technology as the only biofiltration system to utilize patented horizontal flow, allowing for a smaller
footprint, higher treatment capacity, and a wide range of versatility. While most biofilters use little
or no pretreatment, the Modular Wetlands® incorporates an advanced pretreatment chamber that
includes separation and pre-filter cartridges. In this chamber, sediment and hydrocarbons are removed
from runoff before entering the biofiltration chamber, reducing maintenance costs and improving
performance.
Horizontal flow also gives the system the unique ability to adapt to the environment
through a variety of configurations, bypass orientations, and diversion applications.
The Urban Impact
For hundreds of years, natural wetlands surrounding our shores have
played an integral role as nature’s stormwater treatment system.
But as cities grow and develop, our environment’s natural
filtration systems are blanketed with impervious roads,
rooftops, and parking lots.
Bio Clean understands this loss and has spent
years re-establishing nature’s presence in urban
areas, and rejuvenating waterways with the
Modular Wetlands® System Linear.
APPROVALS
The Modular Wetlands® System Linear has successfully met years of challenging technical reviews and
testing from some of the most prestigious and demanding agencies in the nation and perhaps the world.
Here is a list of some of the most high-profile approvals, certifications, and verifications from around the
country.
VA
Washington State Department of Ecology TAPE Approved
The MWS Linear is approved for General Use Level Designation (GULD) for Basic,
Enhanced, and Phosphorus treatment at 1 gpm/ft2 loading rate. The highest performing
BMP on the market for all main pollutant categories.
California Water Resources Control Board, Full Capture Certification
The Modular Wetlands® System is the first biofiltration system to receive certification as
a full capture trash treatment control device.
Virginia Department of Environmental Quality, Assignment
The Virginia Department of Environmental Quality assigned the MWS Linear the
highest phosphorus removal rating for manufactured treatment devices to meet the new
Virginia Stormwater Management Program (VSMP) regulation technical criteria.
Maryland Department of the Environment, Approved ESD
Granted Environmental Site Design (ESD) status for new construction, redevelopment,
and retrofitting when designed in accordance with the design manual.
MASTEP Evaluation
The University of Massachusetts at Amherst – Water Resources Research Center issued
a technical evaluation report noting removal rates up to 84% TSS, 70% total phosphorus,
68.5% total zinc, and more.
Rhode Island Department of Environmental Management, Approved BMP
Approved as an authorized BMP and noted to achieve the following minimum removal
efficiencies: 85% TSS, 60% pathogens, 30% total phosphorus, and 30% total nitrogen.
ADVANTAGES
• FLOW CONTROL
• NO DEPRESSED PLANTER AREA
• AUTO DRAINDOWN MEANS NO
MOSQUITO VECTOR
• HORIZONTAL FLOW BIOFILTRATION
• GREATER FILTER SURFACE AREA
• PRETREATMENT CHAMBER
• PATENTED PERIMETER VOID AREA
PERFORMANCE
The Modular Wetlands® continues to outperform other treatment methods with superior pollutant
removal for TSS, heavy metals, nutrients, hydrocarbons, and bacteria. Since 2007 the Modular
Wetlands® has been field tested on numerous sites across the country and is proven to effectively
remove pollutants through a combination of physical, chemical, and biological filtration processes.
In fact, the Modular Wetlands® harnesses some of the same biological processes found in natural
wetlands in order to collect, transform, and remove even the most harmful pollutants.
CA
OPERATION
The Modular Wetlands® System Linear is the most efficient and versatile biofiltration system on the
market, and it is the only system with horizontal flow which:
• Improves performance
• Reduces footprint
• Minimizes maintenance
Figure 1 & Figure 2 illustrate the invaluable benefits of horizontal flow and the multiple treatment stages.
Cartridge Housing
Pre-filter Cartridge
Curb Inlet
Figure 1Individual Media Filters
HORIZONTAL FLOW
• Less clogging than downward flow biofilters
• Water flow is subsurface
• Improves biological filtration
PATENTED PERIMETER VOID AREA
• Vertically extends void area between the walls and
the WetlandMEDIA™ on all four sides
• Maximizes surface area of the media for higher
treatment capacity
WETLANDMEDIA
• Contains no organics and removes phosphorus
• Greater surface area and 48% void space
• Maximum evapotranspiration
• High ion exchange capacity and lightweight
FLOW CONTROL
• Orifice plate controls flow of water
through WetlandMEDIA™ to a level lower
than the media’s capacity
• Extends the life of the media and
improves performance
DRAINDOWN FILTER
• The draindown is an optional feature that
completely drains the pretreatment
chamber
• Water that drains from the pretreatment
chamber between storm events will be
treated
2x to 3x more surface area than traditional downward flow bioretention systems.Figure 2,
Top View
SEPARATION
• Trash, sediment, and debris are separated before
entering the pre-filter cartridges
• Designed for easy maintenance access
PRE-FILTER CARTRIDGES
• Over 25 sq. ft. of surface area per cartridge
• Utilizes BioMediaGREEN™ filter material
• Removes over 80% of TSS and 90% of hydrocarbons
• Prevents pollutants that cause clogging from migrating
to the biofiltration chamber
2
DISCHARGE3
BIOFILTRATION2PRETREATMENT1
PERIMETER
V
O
I
D
A
R
E
A
Flow Control
RiserDraindown Line Outlet Pipe
Vertical Underdrain
Manifold
BioMediaGREEN™
WetlandMEDIA™
1
3
CONFIGURATIONS
The Modular Wetlands® System Linear is the preferred biofiltration system of civil engineers across the
country due to its versatile design. This highly versatile system has available “pipe-in” options on most
models, along with built-in curb or grated inlets for simple integration into your storm drain design.
CURB TYPE
The Curb Type configuration accepts sheet flow through a curb opening
and is commonly used along roadways and parking lots. It can be used in
sump or flow-by conditions. Length of curb opening varies based on model
and size.
GRATE TYPE
The Grate Type configuration offers the same features and benefits as the
Curb Type but with a grated/drop inlet above the systems pretreatment
chamber. It has the added benefit of allowing pedestrian access over the
inlet. ADA-compliant grates are available to assure easy and safe access.
The Grate Type can also be used in scenarios where runoff needs to be
intercepted on both sides of landscape islands.
DOWNSPOUT TYPE
The Downspout Type is a variation of the Vault Type and is designed to
accept a vertical downspout pipe from rooftop and podium areas. Some
models have the option of utilizing an internal bypass, simplifying the overall
design. The system can be installed as a raised planter, and the exterior can
be stuccoed or covered with other finishes to match the look of adjacent
buildings.
VAULT TYPE
The system’s patented horizontal flow biofilter is able to accept inflow pipes
directly into the pretreatment chamber, meaning the Modular Wetlands®
can be used in end-of-the-line installations. This greatly improves feasibility
over typical decentralized designs that are required with other biofiltration/
bioretention systems. Another benefit of the “pipe-in” design is the ability
to install the system downstream of underground detention systems to
meet water quality volume requirements.
ORIENTATIONS
INTERNAL BYPASS WEIR
(SIDE-BY-SIDE ONLY)
The Side-By-Side orientation places the
pretreatment and discharge chambers adjacent
to one another allowing for integration of internal
bypass. The wall between these chambers can act
as a bypass weir when flows exceed the system’s
treatment capacity, thus allowing bypass from the
pretreatment chamber directly to the discharge
chamber.
EXTERNAL DIVERSION WEIR STRUCTURE
This traditional offline diversion method can be
used with the Modular Wetlands® in scenarios
where runoff is being piped to the system. These
simple and effective structures are generally
configured with two outflow pipes. The first is a
smaller pipe on the upstream side of the diversion
weir - to divert low flows over to the Modular
Wetlands® for treatment. The second is the main
pipe that receives water once the system has
exceeded treatment capacity and water flows over
the weir.
FLOW-BY-DESIGN
This method is one in which the system is placed
just upstream of a standard curb or grate inlet to
intercept the first flush. Higher flows simply pass
by the Modular Wetlands® and into the standard
inlet downstream.
END-TO-END
The End-To-End orientation
places the pretreatment and
discharge chambers
on opposite ends of the
biofiltration chamber,
therefore minimizing the width
of the system to 5 ft. (outside
dimension). This orientation is perfect
for linear projects and street retrofits
where existing utilities and sidewalks limit the
amount of space available for installation. One
limitation of this orientation is that bypass must
be external.
SIDE-BY-SIDE
The Side-By-Side
orientation places the
pretreatment and
discharge chamber
adjacent to one
another with the
biofiltration chamber running
parallel on either side. This
minimizes the system length, providing a highly
compact footprint. It has been proven useful in
situations such as streets with directly adjacent
sidewalks, as half of the system can be placed
under that sidewalk. This orientation also offers
internal bypass options as discussed below.
DVERT LOW FLOW DIVERSION
This simple yet innovative diversion trough can be
installed in existing or new curb and grate inlets
to divert the first flush to the Modular Wetlands®
via pipe. It works similar to a rain gutter and is
installed just below the opening into the inlet. It
captures the low flows and channels them over
to a connecting pipe exiting out the wall of the
inlet and leading to the MWS Linear. The DVERT
is perfect for retrofit and green street applications
that allow the Modular Wetlands® to be installed
anywhere space is available.
DVERT Trough
BYPASS
MODEL #DIMENSIONS
WETLANDMEDIA
SURFACE AREA
(sq. ft.)
TREATMENT FLOW
RATE
(cfs)
MWS-L-4-4 4’ x 4’23 0.052
MWS-L-4-6 4’ x 6’32 0.073
MWS-L-4-8 4’ x 8’50 0.115
MWS-L-4-13 4’ x 13’63 0.144
MWS-L-4-15 4’ x 15’76 0.175
MWS-L-4-17 4’ x 17’90 0.206
MWS-L-4-19 4’ x 19’103 0.237
MWS-L-4-21 4’ x 21’117 0.268
MWS-L-6-8 7’ x 9’64 0.147
MWS-L-8-8 8’ x 8’100 0.230
MWS-L-8-12 8’ x 12’151 0.346
MWS-L-8-16 8’ x 16’201 0.462
MWS-L-8-20 9’ x 21’252 0.577
MWS-L-8-24 9’ x 25’302 0.693
MWS-L-10-20 10' x 20'302 0.693
VOLUME-BASED DESIGNS
HORIZONTAL FLOW BIOFILTRATION ADVANTAGE
The Modular Wetlands® System Linear offers a unique advantage in the world of biofiltration due to its exclusive
horizontal flow design: Volume-Based Design. No other biofilter has the ability to be placed downstream
of detention ponds, extended dry detention basins, underground storage systems and permeable paver
reservoirs. The systems horizontal flow configuration and built-in orifice control allows it to be installed with
just 6” of fall between inlet and outlet pipe for a simple connection to projects with shallow downstream tie-
in points. In the example above, the Modular Wetlands® is installed downstream of underground box culvert
storage. Designed for the water quality volume, the Modular Wetlands® will treat and discharge the required
volume within local draindown time requirements.
DESIGN SUPPORT
Bio Clean engineers are trained to provide you with superior support for all volume sizing configurations
throughout the country. Our vast knowledge of state and local regulations allow us to quickly and efficiently
size a system to maximize feasibility. Volume control and hydromodification regulations are expanding the
need to decrease the cost and size of your biofiltration system. Bio Clean will help you realize these cost
savings with the Modular Wetlands®, the only biofilter than can be used downstream of storage BMPs.
SPECIFICATIONS
FLOW-BASED DESIGNS
The Modular Wetlands® System Linear can be used in stand-alone applications to meet treatment flow
requirements. Since the Modular Wetlands® is the only biofiltration system that can accept inflow pipes
several feet below the surface, it can be used not only in decentralized design applications but also as a large
central end-of-the-line application for maximum feasibility.
ADVANTAGES
• BUILT-IN ORIFICE CONTROL STRUCTURE
• WORKS WITH DEEP INSTALLATIONS
• LOWER COST THAN FLOW-BASED DESIGN
• MEETS LID REQUIREMENTS
Modular Wetlands® with
Arch Plastic Chambers
Modular Wetlands® with
Box Culvert Prestorage
PLANT SELECTION
Abundant plants, trees, and grasses bring value and an aesthetic benefit
to any urban setting, but those in the Modular Wetlands® System Linear
do even more - they increase pollutant removal. What’s not seen, but
very important, is that below grade, the stormwater runoff/flow is being
subjected to nature’s secret weapon: a dynamic physical, chemical, and
biological process working to break down and remove non-point source pollutants. The flow rate is controlled in
the Modular Wetlands®, giving the plants more contact time so that pollutants are more successfully decomposed,
volatilized, and incorporated into the biomass of the Modular Wetlands’® micro/macro flora and fauna.
A wide range of plants are suitable for use in the Modular Wetlands®, but selections vary by location and climate.
View suitable plants by visiting biocleanenvironmental.com/plants.
INSTALLATION MAINTENANCE
The Modular Wetlands® is simple, easy to install,
and has a space-efficient design that offers lower
excavation and installation costs compared to
traditional tree-box type systems. The structure of
the system resembles precast catch basin or utility
vaults and is installed in a similar fashion.
The system is delivered fully assembled for quick
installation. Generally, the structure can be unloaded
and set in place in 15 minutes. Our experienced
team of field technicians is available to supervise
installations and provide technical support.
Reduce your maintenance costs, man hours, and
materials with the Modular Wetlands®. Unlike other
biofiltration systems that provide no pretreatment,
the Modular Wetlands® is a self-contained
treatment train which incorporates simple and
effective pretreatment.
Maintenance requirements for the biofilter itself are
almost completely eliminated, as the pretreatment
chamber removes and isolates trash, sediments, and
hydrocarbons. What’s left is the simple maintenance
of an easily accessible pretreatment chamber that
can be cleaned by hand or with a standard vac
truck. Only periodic replacement of low-cost media
in the pre-filter cartridges is required for long-term
operation, and there is absolutely no need to replace
expensive biofiltration media.
INDUSTRIAL
Many states enforce strict regulations for discharges
from industrial sites. The Modular Wetlands® has
helped various sites meet difficult EPA-mandated
effluent limits for dissolved metals and other
pollutants.
PARKING LOTS
Parking lots are designed to maximize space and the
Modular Wetlands’® 4 ft. standard planter width
allows for easy integration into parking lot islands
and other landscape medians.
MIXED USE
The Modular Wetlands® can be installed as a raised
planter to treat runoff from rooftops or patios,
making it perfect for sustainable “live-work” spaces.
RESIDENTIAL
Low to high density developments can benefit from
the versatile design of the Modular Wetlands®. The
system can be used in both decentralized LID design
and cost-effective end-of-the-line configurations.
STREETS
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space. The Modular Wetlands® is very adaptable,
and it offers the smallest footprint to work around
the constraints of existing utilities on retrofit projects.
COMMERCIAL
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Wetlands® can treat far more area in less space,
meeting treatment and volume control requirements.
APPLICATIONS
The Modular Wetlands® System Linear has been successfully used on numerous new construction and retrofit
projects. The system’s superior versatility makes it beneficial for a wide range of stormwater and waste water
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More applications include:
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A Forterra Company
010419R1A
5796 Armada Drive Suite 250
Carlsbad, CA 92008
855.566.3938
stormwater@forterrabp.com
biocleanenvironmental.com
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 5
Drainage Report
Attach project’s drainage report. Refer to the Subdivision Manual to determine the reporting
requirements.
PRELIMINARY
DRAINAGE REPORT
NAKANO
City of Chula Vista, CA
November 3, 2022
City of Chula Vista TM#PCS21-0001,
City of San Diego PTS 647766
APN #: 624-071-02
Project Address:
North of the intersection of Dennery Rd & Regatta Lane, Chula Vista,
CA 92154
Prepared For:
TriPointe Homes
13400 Sabre Springs Parkway, Suite 200
San Diego, CA 92128
Prepared By:
PDC Job No. 4409.02
Prepared by: J.Novoa, PE
Under the supervision of
________________________________
Chelisa A. Pack, PE RCE 71026
Registration Expires 6/30/23
TABLE OF CONTENTS
1. INTRODUCTION .................................................................................................................. 1
2. EXISTING AND PROPOSED DRAINAGE PATTERNS AND IMPROVEMENTS .......... 2
2.1 Existing Drainage Patterns .............................................................................................. 2
2.2 Proposed Drainage Improvements .................................................................................. 3
3. HYDROLOGY CRITERIA, METHODOLOGY, AND RESULTS ...................................... 3
3.1 Hydrology Criteria .......................................................................................................... 4
3.2 Hydrologic Methodology ................................................................................................ 4
3.3 Description of Hydrologic Modeling Software .............................................................. 5
3.4 Hydrology Results .......................................................................................................... 5
4. HYDRAULIC CRITERIA, METHODOLOGY, AND RESULTS ....................................... 6
5. DETENTION .......................................................................................................................... 6
6. FEMA LETTER OF MAP AMENDMENT .......................................................................... 6
7. CONCLUSION ....................................................................................................................... 7
TABLES
Table 1: Hydrology Criteria ............................................................................................................ 4
Table 2: Hydrology Results ............................................................................................................ 5
APPENDICES
1 Supplemental Information (Intensity Duration Frequency Curve, Runoff
Coefficients)
2 Existing Conditions Rational Method Computer Output
3 Proposed Conditions Rational Method Computer Output
4 Hydraulic Calculations
5 Preliminary Detention Calculations
6 Drainage Exhibits
7 LOMA
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1
1. INTRODUCTION
This drainage report has been prepared in support of the preliminary design of the proposed storm
drain improvements associated with the Nakano development project (Project) for a Tentative
Map(TM) submittal. The Nakano Project is a development project on a previously graded site
which will consist of a combination of detached condominiums, duplexes and multi-family
dwelling units for residential use. Total Project area is 23.8 acres that is currently a vacant lot. The
project is located south of Otay River, and is bounded on the south by a Kaiser Permanente building
and hillside, on the east by existing residential homes and on the west by I-805 freeway. The
project proposes a total of 61 detached condominiums, 84 duplexes, and 70 multi-family dwelling
units. The project is currently within the City of Chula Vista jurisdiction, but may be annexed into
the City of San Diego before development. Refer to the Vicinity Map below: Figure 1 for the
Project location.
Figure 1: Vicinity Map
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2
At present the site is mostly undeveloped land consisting primarily of natural terrain, with brush
and some areas of larger trees along the existing channel going through project site from south to
north along the eastern edge of the property carrying mostly runon from the south.
Presently all runoff flows across the site from south to north, and then sheet flows towards the
Otay River. The proposed project will continue to send all runoff to the north with a proposed
upgraded storm drain that will be constructed to convey water from the site to downstream. The
eastern existing flowpath will mostly be preserved and a low flow splitter will be constructed to
maintain low flows through this existing area, while the high flows will be piped through the site
to the north center outlet. Two biofiltration basins and a Modular Wetland Unit with a detention
vault will be implemented to manage water quality while also providing some peak flow detention.
From a regional drainage perspective, the runoff through the Project site includes 10.1 acres of
upstream offsite area immediately south to the project boundary. The western side of offsite
upstream areas drain through the site and along the western edge. The proposed site’s storm drain
system will outlet into the existing terrain along the north end of the project, and runoff will sheet
flow towards the Otay River, which eventually drains into the San Diego Bay. For water quality
management concerns refer to the Storm Water Quality Management Plan (SWQMP) prepared by
Project Design Consultants for the proposed project treatment BMPs. The project will require an
a 401 and 404 permit as well as CA DFW 1602 permit.
2. EXISTING AND PROPOSED DRAINAGE PATTERNS AND IMPROVEMENTS
The following sections provide descriptions of the existing and proposed drainage patterns and
improvements for the project.
2.1 Existing Drainage Patterns
There are minimal on-site drainage facilities, except for an existing natural channel along the
eastern edge of the property. At present, the majority of the site runoff flows via sheet flow to the
north. Upstream of the site, runoff from areas including hillside and a Kaiser Permanente building
flow through and along the eastern and western edges of the project site. There is an existing
channel along the eastern side of the project that runs along the edge of the property boundary.
Refer to Exhibit A in Appendix 6 for the existing condition drainage map.
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3
2.2 Proposed Drainage Improvements
The site will continue to discharge to north with brow ditches and piped storm drain to convey the
runon. The project site will include a private storm drain system to convey the onsite flow. The
eastern runon will enter a new RCP stormdrain pipe and will take the high flows through the site
to outletting the north center outfall of the project. A low flow splitter will be constructed to
maintain flow through the existing flowpath. A small wall parallel to the biofiltration basin will be
installed to ensure the runon flow does not enter the project site. This area was designed to not
commingle the upstream runon and allow a portion of the channel to remain natural. The proposed
drainage improvements include private storm drains collecting rooftop and surface drainage. Refer
to Exhibit B in Appendix 6 for the proposed condition drainage map.
Water quality requirements will be managed with two biofiltration basins and a detention vault
upstream of a modular wetland unit. The detention vault will provide peak flow detention to
mitigate for peak flows.
3. HYDROLOGY CRITERIA, METHODOLOGY, AND RESULTS
Hydrologic modeling was performed per City of Chula Vista Subdivision Manual criteria to
provide the design flows for storm drain design and improvements.
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4
3.1 Hydrology Criteria
Table 1 summarizes the hydrology assumptions and criteria used for hydrologic modeling.
Table 1: Hydrology Criteria
Existing and Proposed
Hydrology:
100-year storm frequency
Soil Type: Hydrologic Soil Group C & D
Land Use / Runoff Coefficients: Based on criteria presented in the Revised 2012 City of
Chula Vista Subdivision Manual Section 3-200
Hydrology/Drainage/Urban Runoff.
Rainfall intensity: Based on intensity duration frequency relationships
presented in the 2017 Chula Vista Design Standards &
Revised 2012 City of Chula Vista Subdivision Manual
Section 3-200 Hydrology/Drainage/Urban Runoff, see
Appendix 1 .
3.2 Hydrologic Methodology
The Rational Method was used to determine the onsite 100-year storm flow for the design of the
Project storm drainpipe improvements. The goal of this analysis was to:
Determine the design flows for the sizing of any proposed storm drain improvements.
Determine the differences in the drainage conditions between existing and proposed
conditions to confirm there are no significant downstream impacts.
The AES Modified Rational Method program was used to calculate onsite and offsite runoff for
the 100-year storm event. The runoff coefficient for hillsides depended on the steepness and ranged
from 0.45-0.6, which were used for the existing onsite conditions while higher runoff coefficients
for normal residential development, dense residential, and paved surfaces were used for the
proposed onsite condition. Offsite hydrology runoff coefficients were based on land uses apparent
from aerial photography, which includes vegetated slopes (Flat, Rolling, Hilly and Steep
depending on the slope %).
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5
3.3 Description of Hydrologic Modeling Software
The Modified Rational Method was used to determine the 100-year storm flow for the design of
the storm system. The Advanced Engineering Software (AES) Rational Method Program was used
to perform the hydrologic calculations. This section provides a brief explanation of the
computational procedure used in the computer model.
The AES Modified Rational Method Hydrology Program is a computer-aided design program
where the user develops a node link model of the watershed. Developing independent node link
models for each interior watershed and linking these sub-models together at confluence points
creates the node link model. The intensity-duration-frequency relationships are applied to each of
the drainage areas in the model to get the peak flow rates at each point of interest.
3.4 Hydrology Results
The Rational Method as presented in the City of Chula Vista Subdivision Manual and County of
San Diego Hydrology Manual was used to calculate the existing and proposed conditions peak
storm flows. Table 2 below summarizes the Rational Method results for the comparison of the
existing and proposed project site.
Table 2: Hydrology Results
The site will detain post-project 100-year flows to less than pre-project 100-year flows. Final
detention routing will be provided during final engineering, however, preliminary calculations are
provided in Appendix 5.
SYSTEM AREA TC Q100 SYSTEM AREA TC Q100
(ac) (min) (cfs)(ac) (min) (cfs)
1200 16.3 51.9
130 18.9 11.86 33.4 1300 2.7 10.43 6.5
160 3.5 10.17 7.9 1600 3.3 9.60 7.7
TOTAL 38.2 91.5 TOTAL 38.6 80.3
GRAND TOTAL 38.2 91.5 GRAND TOTAL 38.6 80.3
PROPOSED CONDITION (WITH DETENTION)
NAKANO HYDROLOGY SUMMARY
16.3 13.41 100
# 1
OUTFALL
OF
INTEREST
EXISTING CONDITION
42.8 (Undetained)
14.2 (Detained) System 1100(including Sys 1000)15.8 9.98 50.2
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6
4. HYDRAULIC CRITERIA, METHODOLOGY, AND RESULTS
Hydraulic calculations for pipes, inlets, and ditches will be performed during final engineering.
5. DETENTION
The vault was sized to attenuate post-project peak flow rates to pre-project levels for the 100-year
storm event and water quality pollutant control. By including the north vault for detention, the
post-project peak flows will be able to be reduced to below pre-project levels. Detention results
from routing the basin outflow hydrographs will be included during final engineering.
6. FEMA LETTER OF MAP AMENDMENT
A Letter of Map Amendment (LOMA) was performed and certified that the existing property
elevations within the Nakano project are above the Zone AE special flood hazard area base flood
elevations for the Otay River. The entire property was removed from the 100-year floodplain
limits. See Appendix 7 for FEMA approval letter for the LOMA.
The LOMA (Case Reference #20-09-1145A) demonstrated that the existing elevations of the
Nakano property are above the flood elevations indicated by Zone AE as shown in the FIRM Panel
No. 06073C2158G, effective date May 16, 2012. The Zone AE floodplain extends along the north
portion of the site with water surface elevations ranging from 83.8 to 92.7 ft. MSL (NGVD 29).
Note that there a 2.17 conversion from NAVD88 to NGVD29 datum.
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7
7. CONCLUSION
This drainage report has been prepared in support of the preliminary design of the storm drain
improvements for the Tentative Map for the Nakano project. The purpose of this report is to
provide peak discharges for use in designing the private storm drain systems for the project and to
address issues regarding comparing the post-project flows to the pre-project flows. The storm drain
system will be sufficient to satisfy City of Chula Vista criteria in the post-development condition.
APPENDIX 1
Supplemental Information (Intensity Duration Frequency Curve,
Runoff Coefficients)
Project Site
P6=2.4
Project Site
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/29/2019
Page 1 of 4
36
0
5
6
0
0
36
0
5
6
5
0
36
0
5
7
0
0
36
0
5
7
5
0
36
0
5
8
0
0
36
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5
8
5
0
36
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9
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36
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6
0
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36
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36
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0
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36
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36
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36
0
5
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36
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0
0
496560 496610 496660 496710 496760 496810 496860 496910 496960 497010 497060
496560 496610 496660 496710 496760 496810 496860 496910 496960 497010 497060
32° 35' 26'' N
11
7
°
2
'
1
2
'
'
W
32° 35' 26'' N
11
7
°
1
'
5
1
'
'
W
32° 35' 15'' N
11
7
°
2
'
1
2
'
'
W
32° 35' 15'' N
11
7
°
1
'
5
1
'
'
W
N
Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84
0 100 200 400 600
Feet
0 35 70 140 210
Meters
Map Scale: 1:2,460 if printed on A landscape (11" x 8.5") sheet.
Soil Map may not be valid at this scale.
MAP LEGEND MAP INFORMATION
Area of Interest (AOI)
Area of Interest (AOI)
Soils
Soil Rating Polygons
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Lines
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Soil Rating Points
A
A/D
B
B/D
C
C/D
D
Not rated or not available
Water Features
Streams and Canals
Transportation
Rails
Interstate Highways
US Routes
Major Roads
Local Roads
Background
Aerial Photography
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: San Diego County Area, California
Survey Area Data: Version 14, Sep 16, 2019
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Dec 7, 2014—Jan 4,
2015
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/29/2019
Page 2 of 4
Hydrologic Soil Group
Map unit symbol Map unit name Rating Acres in AOI Percent of AOI
Rm Riverwash D 2.6 14.1%
SbA Salinas clay loam, 0 to 2
percent slopes, warm
MAAT, MLRA 19
C 15.7 85.9%
Totals for Area of Interest 18.3 100.0%
Description
Hydrologic soil groups are based on estimates of runoff potential. Soils are
assigned to one of four groups according to the rate of water infiltration when the
soils are not protected by vegetation, are thoroughly wet, and receive
precipitation from long-duration storms.
The soils in the United States are assigned to four groups (A, B, C, and D) and
three dual classes (A/D, B/D, and C/D). The groups are defined as follows:
Group A. Soils having a high infiltration rate (low runoff potential) when
thoroughly wet. These consist mainly of deep, well drained to excessively
drained sands or gravelly sands. These soils have a high rate of water
transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well
drained soils that have moderately fine texture to moderately coarse texture.
These soils have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of
water transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink-swell
potential, soils that have a high water table, soils that have a claypan or clay
layer at or near the surface, and soils that are shallow over nearly impervious
material. These soils have a very slow rate of water transmission.
If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is
for drained areas and the second is for undrained areas. Only the soils that in
their natural condition are in group D are assigned to dual classes.
Rating Options
Aggregation Method: Dominant Condition
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/29/2019
Page 3 of 4
Component Percent Cutoff: None Specified
Tie-break Rule: Higher
Hydrologic Soil Group—San Diego County Area, California
Natural Resources
Conservation Service
Web Soil Survey
National Cooperative Soil Survey
10/29/2019
Page 4 of 4
APPENDIX 2
Existing Conditions Rational Method Computer Output
S100E100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO 4409 *
* SYSTEM 100 - EXISTING CONDITIONS *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: S100E100.DAT
TIME/DATE OF STUDY: 11:37 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 100.00 TO NODE 105.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 1.06
TOTAL AREA(ACRES) = 0.28 TOTAL RUNOFF(CFS) = 1.06
Printed: 6/17/2022 12:24:38 PM PM Modified: 6/14/2022 11:37:18 AM AM Page 1 of 4
S100E100.RES
****************************************************************************
FLOW PROCESS FROM NODE 105.00 TO NODE 110.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 240.00 DOWNSTREAM(FEET) = 151.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 825.00 CHANNEL SLOPE = 0.1079
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 2.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.643
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 7.17
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 4.48
AVERAGE FLOW DEPTH(FEET) = 0.16 TRAVEL TIME(MIN.) = 3.07
Tc(MIN.) = 8.07
SUBAREA AREA(ACRES) = 4.28 SUBAREA RUNOFF(CFS) = 11.92
AREA-AVERAGE RUNOFF COEFFICIENT = 0.600
TOTAL AREA(ACRES) = 4.6 PEAK FLOW RATE(CFS) = 12.70
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.22 FLOW VELOCITY(FEET/SEC.) = 5.62
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 110.00 = 825.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 110.00 TO NODE 110.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 8.07
RAINFALL INTENSITY(INCH/HR) = 4.64
TOTAL STREAM AREA(ACRES) = 4.56
PEAK FLOW RATE(CFS) AT CONFLUENCE = 12.70
****************************************************************************
FLOW PROCESS FROM NODE 109.00 TO NODE 110.00 IS CODE = 7
----------------------------------------------------------------------------
>>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================
USER-SPECIFIED VALUES ARE AS FOLLOWS:
TC(MIN) = 5.00 RAIN INTENSITY(INCH/HOUR) = 6.32
TOTAL AREA(ACRES) = 5.50 TOTAL RUNOFF(CFS) = 22.20
****************************************************************************
FLOW PROCESS FROM NODE 110.00 TO NODE 110.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 5.00
RAINFALL INTENSITY(INCH/HR) = 6.32
TOTAL STREAM AREA(ACRES) = 5.50
PEAK FLOW RATE(CFS) AT CONFLUENCE = 22.20
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 12.70 8.07 4.643 4.56
Printed: 6/17/2022 12:24:38 PM PM Modified: 6/14/2022 11:37:18 AM AM Page 2 of 4
S100E100.RES
2 22.20 5.00 6.323 5.50
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 30.07 5.00 6.323
2 29.00 8.07 4.643
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 30.07 Tc(MIN.) = 5.00
TOTAL AREA(ACRES) = 10.1
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 110.00 = 825.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 110.00 TO NODE 115.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 151.00 DOWNSTREAM(FEET) = 132.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 304.00 CHANNEL SLOPE = 0.0625
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 2.500
MANNING'S FACTOR = 0.045 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.726
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .8000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 37.29
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 6.09
AVERAGE FLOW DEPTH(FEET) = 0.86 TRAVEL TIME(MIN.) = 0.83
Tc(MIN.) = 5.83
SUBAREA AREA(ACRES) = 3.16 SUBAREA RUNOFF(CFS) = 14.47
AREA-AVERAGE RUNOFF COEFFICIENT = 0.664
TOTAL AREA(ACRES) = 13.2 PEAK FLOW RATE(CFS) = 50.24
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 1.00 FLOW VELOCITY(FEET/SEC.) = 6.66
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 115.00 = 1129.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 115.00 TO NODE 120.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 132.00 DOWNSTREAM(FEET) = 105.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 896.00 CHANNEL SLOPE = 0.0301
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.049
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .4500
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 52.62
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.60
AVERAGE FLOW DEPTH(FEET) = 0.49 TRAVEL TIME(MIN.) = 4.15
Tc(MIN.) = 9.98
SUBAREA AREA(ACRES) = 2.61 SUBAREA RUNOFF(CFS) = 4.76
AREA-AVERAGE RUNOFF COEFFICIENT = 0.629
TOTAL AREA(ACRES) = 15.8 PEAK FLOW RATE(CFS) = 50.24
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
Printed: 6/17/2022 12:24:38 PM PM Modified: 6/14/2022 11:37:18 AM AM Page 3 of 4
S100E100.RES
DEPTH(FEET) = 0.49 FLOW VELOCITY(FEET/SEC.) = 3.54
LONGEST FLOWPATH FROM NODE 100.00 TO NODE 120.00 = 2025.00 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 15.8 TC(MIN.) = 9.98
PEAK FLOW RATE(CFS) = 50.24
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 12:24:38 PM PM Modified: 6/14/2022 11:37:18 AM AM Page 4 of 4
S130E100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO 4409 *
* SYSTEM 130 - EXISTING CONDITIONS *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: S130E100.DAT
TIME/DATE OF STUDY: 11:38 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 130.00 TO NODE 135.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5500
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 0.90
TOTAL AREA(ACRES) = 0.26 TOTAL RUNOFF(CFS) = 0.90
Printed: 6/17/2022 12:26:22 PM PM Modified: 6/14/2022 11:38:57 AM AM Page 1 of 3
S130E100.RES
****************************************************************************
FLOW PROCESS FROM NODE 135.00 TO NODE 140.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 202.00 DOWNSTREAM(FEET) = 122.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 354.88 CHANNEL SLOPE = 0.2254
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.045 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.198
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 7.94
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.33
AVERAGE FLOW DEPTH(FEET) = 0.14 TRAVEL TIME(MIN.) = 1.78
Tc(MIN.) = 6.78
SUBAREA AREA(ACRES) = 4.50 SUBAREA RUNOFF(CFS) = 14.03
AREA-AVERAGE RUNOFF COEFFICIENT = 0.597
TOTAL AREA(ACRES) = 4.8 PEAK FLOW RATE(CFS) = 14.78
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.19 FLOW VELOCITY(FEET/SEC.) = 4.06
LONGEST FLOWPATH FROM NODE 130.00 TO NODE 140.00 = 1250.88 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 140.00 TO NODE 142.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 122.00 DOWNSTREAM(FEET) = 103.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 675.00 CHANNEL SLOPE = 0.0281
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.827
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .4500
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 19.48
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.73
AVERAGE FLOW DEPTH(FEET) = 0.33 TRAVEL TIME(MIN.) = 4.12
Tc(MIN.) = 10.89
SUBAREA AREA(ACRES) = 5.40 SUBAREA RUNOFF(CFS) = 9.30
AREA-AVERAGE RUNOFF COEFFICIENT = 0.519
TOTAL AREA(ACRES) = 10.2 PEAK FLOW RATE(CFS) = 20.18
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.34 FLOW VELOCITY(FEET/SEC.) = 2.72
LONGEST FLOWPATH FROM NODE 130.00 TO NODE 142.00 = 1925.88 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 142.00 TO NODE 145.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 103.00 DOWNSTREAM(FEET) = 98.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 242.00 CHANNEL SLOPE = 0.0207
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 4.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 1.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.623
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .4500
Printed: 6/17/2022 12:26:22 PM PM Modified: 6/14/2022 11:38:57 AM AM Page 2 of 3
S130E100.RES
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 27.34
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 4.19
AVERAGE FLOW DEPTH(FEET) = 0.54 TRAVEL TIME(MIN.) = 0.96
Tc(MIN.) = 11.86
SUBAREA AREA(ACRES) = 8.78 SUBAREA RUNOFF(CFS) = 14.32
AREA-AVERAGE RUNOFF COEFFICIENT = 0.487
TOTAL AREA(ACRES) = 18.9 PEAK FLOW RATE(CFS) = 33.42
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.60 FLOW VELOCITY(FEET/SEC.) = 4.49
LONGEST FLOWPATH FROM NODE 130.00 TO NODE 145.00 = 2167.88 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 18.9 TC(MIN.) = 11.86
PEAK FLOW RATE(CFS) = 33.42
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 12:26:22 PM PM Modified: 6/14/2022 11:38:57 AM AM Page 3 of 3
S160E100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO 4409 *
* SYSTEM 160 - EXISTING CONDITIONS *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: S160E100.DAT
TIME/DATE OF STUDY: 11:40 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 160.00 TO NODE 165.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5500
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 0.80
TOTAL AREA(ACRES) = 0.23 TOTAL RUNOFF(CFS) = 0.80
Printed: 6/17/2022 12:26:34 PM PM Modified: 6/14/2022 11:40:23 AM AM Page 1 of 2
S160E100.RES
****************************************************************************
FLOW PROCESS FROM NODE 165.00 TO NODE 170.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 166.00 DOWNSTREAM(FEET) = 118.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 158.93 CHANNEL SLOPE = 0.3020
CHANNEL BASE(FEET) = 4.00 "Z" FACTOR = 10.000
MANNING'S FACTOR = 0.035 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.857
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.82
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 4.20
AVERAGE FLOW DEPTH(FEET) = 0.09 TRAVEL TIME(MIN.) = 0.63
Tc(MIN.) = 5.63
SUBAREA AREA(ACRES) = 0.58 SUBAREA RUNOFF(CFS) = 2.04
AREA-AVERAGE RUNOFF COEFFICIENT = 0.586
TOTAL AREA(ACRES) = 0.8 PEAK FLOW RATE(CFS) = 2.78
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.11 FLOW VELOCITY(FEET/SEC.) = 4.87
LONGEST FLOWPATH FROM NODE 160.00 TO NODE 170.00 = 400.93 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 170.00 TO NODE 175.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 118.00 DOWNSTREAM(FEET) = 100.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 681.00 CHANNEL SLOPE = 0.0264
CHANNEL BASE(FEET) = 4.00 "Z" FACTOR = 10.000
MANNING'S FACTOR = 0.035 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.001
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5500
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 5.85
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.50
AVERAGE FLOW DEPTH(FEET) = 0.32 TRAVEL TIME(MIN.) = 4.54
Tc(MIN.) = 10.17
SUBAREA AREA(ACRES) = 2.73 SUBAREA RUNOFF(CFS) = 6.01
AREA-AVERAGE RUNOFF COEFFICIENT = 0.558
TOTAL AREA(ACRES) = 3.5 PEAK FLOW RATE(CFS) = 7.91
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.37 FLOW VELOCITY(FEET/SEC.) = 2.76
LONGEST FLOWPATH FROM NODE 160.00 TO NODE 175.00 = 1081.93 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 3.5 TC(MIN.) = 10.17
PEAK FLOW RATE(CFS) = 7.91
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 12:26:34 PM PM Modified: 6/14/2022 11:40:23 AM AM Page 2 of 2
APPENDIX 3
Proposed Conditions Rational Method Computer Output
1000P100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO - PROPOSED CONDITION 4409 *
* SYSTEM 1000 END AT 1038 FOR DETENTION *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: 1000P100.DAT
TIME/DATE OF STUDY: 09:46 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 12.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 14.5 8.0 0.018/0.018/0.020 0.50 1.50 0.0313 0.125 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 1000.00 TO NODE 1001.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .9000
INITIAL SUBAREA FLOW-LENGTH(FEET) = 123.00
UPSTREAM ELEVATION(FEET) = 193.00
DOWNSTREAM ELEVATION(FEET) = 184.00
ELEVATION DIFFERENCE(FEET) = 9.00
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 1.854
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 1 of 18
1000P100.RES
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 100.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.
SUBAREA RUNOFF(CFS) = 0.46
TOTAL AREA(ACRES) = 0.08 TOTAL RUNOFF(CFS) = 0.46
****************************************************************************
FLOW PROCESS FROM NODE 1001.00 TO NODE 1002.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 184.00 DOWNSTREAM ELEVATION(FEET) = 118.00
STREET LENGTH(FEET) = 713.50 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.85
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.22
HALFSTREET FLOOD WIDTH(FEET) = 5.29
AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.99
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 1.12
STREET FLOW TRAVEL TIME(MIN.) = 2.38 Tc(MIN.) = 4.24
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .9000
AREA-AVERAGE RUNOFF COEFFICIENT = 0.900
SUBAREA AREA(ACRES) = 0.49 SUBAREA RUNOFF(CFS) = 2.79
TOTAL AREA(ACRES) = 0.6 PEAK FLOW RATE(CFS) = 3.24
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.26 HALFSTREET FLOOD WIDTH(FEET) = 7.22
FLOW VELOCITY(FEET/SEC.) = 5.54 DEPTH*VELOCITY(FT*FT/SEC.) = 1.43
LONGEST FLOWPATH FROM NODE 1000.00 TO NODE 1002.00 = 836.50 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1002.00 TO NODE 1003.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 114.00 DOWNSTREAM(FEET) = 113.56
FLOW LENGTH(FEET) = 22.80 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 7.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.58
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3.24
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 4.29
LONGEST FLOWPATH FROM NODE 1000.00 TO NODE 1003.00 = 859.30 FEET.
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 2 of 18
1000P100.RES
****************************************************************************
FLOW PROCESS FROM NODE 1002.00 TO NODE 1003.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 4.29
RAINFALL INTENSITY(INCH/HR) = 6.32
TOTAL STREAM AREA(ACRES) = 0.57
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.24
****************************************************************************
FLOW PROCESS FROM NODE 1014.00 TO NODE 1015.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .8500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 146.70
UPSTREAM ELEVATION(FEET) = 193.00
DOWNSTREAM ELEVATION(FEET) = 184.00
ELEVATION DIFFERENCE(FEET) = 9.00
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 2.458
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 100.00
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.
SUBAREA RUNOFF(CFS) = 0.54
TOTAL AREA(ACRES) = 0.10 TOTAL RUNOFF(CFS) = 0.54
****************************************************************************
FLOW PROCESS FROM NODE 1015.00 TO NODE 1016.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 184.00 DOWNSTREAM ELEVATION(FEET) = 118.00
STREET LENGTH(FEET) = 668.70 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.67
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.22
HALFSTREET FLOOD WIDTH(FEET) = 4.90
AVERAGE FLOW VELOCITY(FEET/SEC.) = 4.98
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 1.08
STREET FLOW TRAVEL TIME(MIN.) = 2.24 Tc(MIN.) = 4.70
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
NOTE: RAINFALL INTENSITY IS BASED ON Tc = 5-MINUTE.
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .8500
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 3 of 18
1000P100.RES
AREA-AVERAGE RUNOFF COEFFICIENT = 0.850
SUBAREA AREA(ACRES) = 0.42 SUBAREA RUNOFF(CFS) = 2.26
TOTAL AREA(ACRES) = 0.5 PEAK FLOW RATE(CFS) = 2.79
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.25 HALFSTREET FLOOD WIDTH(FEET) = 6.59
FLOW VELOCITY(FEET/SEC.) = 5.49 DEPTH*VELOCITY(FT*FT/SEC.) = 1.36
LONGEST FLOWPATH FROM NODE 1014.00 TO NODE 1016.00 = 815.40 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1016.00 TO NODE 1003.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 114.00 DOWNSTREAM(FEET) = 113.66
FLOW LENGTH(FEET) = 8.10 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 12.000
DEPTH OF FLOW IN 12.0 INCH PIPE IS 5.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.51
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 2.79
PIPE TRAVEL TIME(MIN.) = 0.02 Tc(MIN.) = 4.71
LONGEST FLOWPATH FROM NODE 1014.00 TO NODE 1003.00 = 823.50 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1016.00 TO NODE 1003.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 4.71
RAINFALL INTENSITY(INCH/HR) = 6.32
TOTAL STREAM AREA(ACRES) = 0.52
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.79
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 3.24 4.29 6.323 0.57
2 2.79 4.71 6.323 0.52
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 5.79 4.29 6.323
2 6.04 4.71 6.323
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 6.04 Tc(MIN.) = 4.71
TOTAL AREA(ACRES) = 1.1
LONGEST FLOWPATH FROM NODE 1000.00 TO NODE 1003.00 = 859.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1003.00 TO NODE 1017.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 4 of 18
1000P100.RES
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 113.65 DOWNSTREAM(FEET) = 113.37
FLOW LENGTH(FEET) = 27.50 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 11.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.89
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 6.04
PIPE TRAVEL TIME(MIN.) = 0.08 Tc(MIN.) = 4.79
LONGEST FLOWPATH FROM NODE 1000.00 TO NODE 1017.00 = 886.80 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1003.00 TO NODE 1017.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 4.79
RAINFALL INTENSITY(INCH/HR) = 6.32
TOTAL STREAM AREA(ACRES) = 1.09
PEAK FLOW RATE(CFS) AT CONFLUENCE = 6.04
****************************************************************************
FLOW PROCESS FROM NODE 1009.00 TO NODE 1010.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 0.99
TOTAL AREA(ACRES) = 0.26 TOTAL RUNOFF(CFS) = 0.99
****************************************************************************
FLOW PROCESS FROM NODE 1010.00 TO NODE 1011.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 206.00 DOWNSTREAM(FEET) = 146.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 197.00 CHANNEL SLOPE = 0.3046
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.045 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.526
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 3.12
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.83
AVERAGE FLOW DEPTH(FEET) = 0.08 TRAVEL TIME(MIN.) = 1.16
Tc(MIN.) = 6.16
SUBAREA AREA(ACRES) = 1.28 SUBAREA RUNOFF(CFS) = 4.24
AREA-AVERAGE RUNOFF COEFFICIENT = 0.600
TOTAL AREA(ACRES) = 1.5 PEAK FLOW RATE(CFS) = 5.11
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.10 FLOW VELOCITY(FEET/SEC.) = 3.31
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1011.00 = 865.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1011.00 TO NODE 1012.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 5 of 18
1000P100.RES
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 146.00 DOWNSTREAM(FEET) = 132.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 28.50 CHANNEL SLOPE = 0.4912
CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 3.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 0.50
CHANNEL FLOW THRU SUBAREA(CFS) = 5.11
FLOW VELOCITY(FEET/SEC.) = 14.83 FLOW DEPTH(FEET) = 0.10
TRAVEL TIME(MIN.) = 0.03 Tc(MIN.) = 6.19
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1012.00 = 894.20 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1012.00 TO NODE 1013.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.508
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6000
SUBAREA AREA(ACRES) = 0.41 SUBAREA RUNOFF(CFS) = 1.35
TOTAL AREA(ACRES) = 1.9 TOTAL RUNOFF(CFS) = 6.44
TC(MIN.) = 6.19
****************************************************************************
FLOW PROCESS FROM NODE 1018.00 TO NODE 1013.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.508
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6078
SUBAREA AREA(ACRES) = 0.36 SUBAREA RUNOFF(CFS) = 1.29
TOTAL AREA(ACRES) = 2.3 TOTAL RUNOFF(CFS) = 7.73
TC(MIN.) = 6.19
****************************************************************************
FLOW PROCESS FROM NODE 1013.00 TO NODE 1017.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 114.00 DOWNSTREAM(FEET) = 113.50
FLOW LENGTH(FEET) = 44.50 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 11.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.67
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 7.73
PIPE TRAVEL TIME(MIN.) = 0.11 Tc(MIN.) = 6.30
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1017.00 = 938.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1013.00 TO NODE 1017.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 6.30
RAINFALL INTENSITY(INCH/HR) = 5.45
TOTAL STREAM AREA(ACRES) = 2.31
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 6 of 18
1000P100.RES
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.73
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 6.04 4.79 6.323 1.09
2 7.73 6.30 5.445 2.31
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 11.92 4.79 6.323
2 12.93 6.30 5.445
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 12.93 Tc(MIN.) = 6.30
TOTAL AREA(ACRES) = 3.4
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1017.00 = 938.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1017.00 TO NODE 1020.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 113.37 DOWNSTREAM(FEET) = 113.00
FLOW LENGTH(FEET) = 139.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 18.8 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.38
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 12.93
PIPE TRAVEL TIME(MIN.) = 0.53 Tc(MIN.) = 6.83
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1020.00 = 1077.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1021.00 TO NODE 1020.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.169
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6904
SUBAREA AREA(ACRES) = 0.29 SUBAREA RUNOFF(CFS) = 0.97
TOTAL AREA(ACRES) = 3.7 TOTAL RUNOFF(CFS) = 13.17
TC(MIN.) = 6.83
****************************************************************************
FLOW PROCESS FROM NODE 1020.00 TO NODE 1022.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 113.00 DOWNSTREAM(FEET) = 111.40
FLOW LENGTH(FEET) = 160.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 14.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.21
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 13.17
PIPE TRAVEL TIME(MIN.) = 0.37 Tc(MIN.) = 7.20
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 7 of 18
1000P100.RES
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1022.00 = 1237.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1022.00 TO NODE 1022.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 7.20
RAINFALL INTENSITY(INCH/HR) = 5.00
TOTAL STREAM AREA(ACRES) = 3.69
PEAK FLOW RATE(CFS) AT CONFLUENCE = 13.17
****************************************************************************
FLOW PROCESS FROM NODE 1023.00 TO NODE 1024.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 114.70
UPSTREAM ELEVATION(FEET) = 116.90
DOWNSTREAM ELEVATION(FEET) = 114.90
ELEVATION DIFFERENCE(FEET) = 2.00
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.922
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 77.44
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.669
SUBAREA RUNOFF(CFS) = 0.74
TOTAL AREA(ACRES) = 0.20 TOTAL RUNOFF(CFS) = 0.74
****************************************************************************
FLOW PROCESS FROM NODE 1024.00 TO NODE 1025.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 114.90 DOWNSTREAM ELEVATION(FEET) = 110.90
STREET LENGTH(FEET) = 222.90 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.76
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.27
HALFSTREET FLOOD WIDTH(FEET) = 8.03
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.53
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.69
STREET FLOW TRAVEL TIME(MIN.) = 1.47 Tc(MIN.) = 7.39
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.914
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 8 of 18
1000P100.RES
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 0.64 SUBAREA RUNOFF(CFS) = 2.04
TOTAL AREA(ACRES) = 0.8 PEAK FLOW RATE(CFS) = 2.68
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.30 HALFSTREET FLOOD WIDTH(FEET) = 9.72
FLOW VELOCITY(FEET/SEC.) = 2.78 DEPTH*VELOCITY(FT*FT/SEC.) = 0.84
LONGEST FLOWPATH FROM NODE 1023.00 TO NODE 1025.00 = 337.60 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1025.00 TO NODE 1022.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 108.00 DOWNSTREAM(FEET) = 107.50
FLOW LENGTH(FEET) = 7.81 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 12.000
DEPTH OF FLOW IN 12.0 INCH PIPE IS 4.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 9.83
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 2.68
PIPE TRAVEL TIME(MIN.) = 0.01 Tc(MIN.) = 7.40
LONGEST FLOWPATH FROM NODE 1023.00 TO NODE 1022.00 = 345.41 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1025.00 TO NODE 1022.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 7.40
RAINFALL INTENSITY(INCH/HR) = 4.91
TOTAL STREAM AREA(ACRES) = 0.84
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.68
****************************************************************************
FLOW PROCESS FROM NODE 1019.00 TO NODE 1026.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 117.20
UPSTREAM ELEVATION(FEET) = 115.70
DOWNSTREAM ELEVATION(FEET) = 113.60
ELEVATION DIFFERENCE(FEET) = 2.10
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.887
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 77.92
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.691
SUBAREA RUNOFF(CFS) = 0.85
TOTAL AREA(ACRES) = 0.23 TOTAL RUNOFF(CFS) = 0.85
****************************************************************************
FLOW PROCESS FROM NODE 1026.00 TO NODE 1027.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 9 of 18
1000P100.RES
UPSTREAM ELEVATION(FEET) = 114.60 DOWNSTREAM ELEVATION(FEET) = 110.90
STREET LENGTH(FEET) = 234.70 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.16
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.29
HALFSTREET FLOOD WIDTH(FEET) = 9.09
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.51
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.73
STREET FLOW TRAVEL TIME(MIN.) = 1.56 Tc(MIN.) = 7.44
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.892
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 0.82 SUBAREA RUNOFF(CFS) = 2.61
TOTAL AREA(ACRES) = 1.0 PEAK FLOW RATE(CFS) = 3.34
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.33 HALFSTREET FLOOD WIDTH(FEET) = 10.97
FLOW VELOCITY(FEET/SEC.) = 2.79 DEPTH*VELOCITY(FT*FT/SEC.) = 0.91
LONGEST FLOWPATH FROM NODE 1019.00 TO NODE 1027.00 = 351.90 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1027.00 TO NODE 1022.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 108.00 DOWNSTREAM(FEET) = 107.50
FLOW LENGTH(FEET) = 22.60 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 7.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 6.99
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3.34
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 7.50
LONGEST FLOWPATH FROM NODE 1019.00 TO NODE 1022.00 = 374.50 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1027.00 TO NODE 1022.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 3
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 3 ARE:
TIME OF CONCENTRATION(MIN.) = 7.50
RAINFALL INTENSITY(INCH/HR) = 4.87
TOTAL STREAM AREA(ACRES) = 1.05
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.34
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 10 of 18
1000P100.RES
1 13.17 7.20 4.997 3.69
2 2.68 7.40 4.909 0.84
3 3.34 7.50 4.869 1.05
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 3 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 18.99 7.20 4.997
2 18.92 7.40 4.909
3 18.83 7.50 4.869
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 18.99 Tc(MIN.) = 7.20
TOTAL AREA(ACRES) = 5.6
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1022.00 = 1237.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1022.00 TO NODE 1028.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 107.50 DOWNSTREAM(FEET) = 105.90
FLOW LENGTH(FEET) = 159.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 17.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.92
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 18.99
PIPE TRAVEL TIME(MIN.) = 0.33 Tc(MIN.) = 7.54
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1028.00 = 1396.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1022.00 TO NODE 1028.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 7.54
RAINFALL INTENSITY(INCH/HR) = 4.85
TOTAL STREAM AREA(ACRES) = 5.58
PEAK FLOW RATE(CFS) AT CONFLUENCE = 18.99
****************************************************************************
FLOW PROCESS FROM NODE 1029.00 TO NODE 1030.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 118.00
UPSTREAM ELEVATION(FEET) = 113.20
DOWNSTREAM ELEVATION(FEET) = 110.60
ELEVATION DIFFERENCE(FEET) = 2.60
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 5.673
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 83.05
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.829
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 11 of 18
1000P100.RES
SUBAREA RUNOFF(CFS) = 0.64
TOTAL AREA(ACRES) = 0.17 TOTAL RUNOFF(CFS) = 0.64
****************************************************************************
FLOW PROCESS FROM NODE 1030.00 TO NODE 1031.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 111.60 DOWNSTREAM ELEVATION(FEET) = 107.60
STREET LENGTH(FEET) = 270.20 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.71
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.28
HALFSTREET FLOOD WIDTH(FEET) = 8.28
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.34
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.65
STREET FLOW TRAVEL TIME(MIN.) = 1.93 Tc(MIN.) = 7.60
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.828
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 0.68 SUBAREA RUNOFF(CFS) = 2.13
TOTAL AREA(ACRES) = 0.9 PEAK FLOW RATE(CFS) = 2.67
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.31 HALFSTREET FLOOD WIDTH(FEET) = 10.09
FLOW VELOCITY(FEET/SEC.) = 2.59 DEPTH*VELOCITY(FT*FT/SEC.) = 0.80
LONGEST FLOWPATH FROM NODE 1029.00 TO NODE 1031.00 = 388.20 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1031.00 TO NODE 1028.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 106.20 DOWNSTREAM(FEET) = 105.90
FLOW LENGTH(FEET) = 7.80 MANNING'S N = 0.013
ESTIMATED PIPE DIAMETER(INCH) INCREASED TO 12.000
DEPTH OF FLOW IN 12.0 INCH PIPE IS 5.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.15
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 2.67
PIPE TRAVEL TIME(MIN.) = 0.02 Tc(MIN.) = 7.61
LONGEST FLOWPATH FROM NODE 1029.00 TO NODE 1028.00 = 396.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1031.00 TO NODE 1028.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 12 of 18
1000P100.RES
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 7.61
RAINFALL INTENSITY(INCH/HR) = 4.82
TOTAL STREAM AREA(ACRES) = 0.85
PEAK FLOW RATE(CFS) AT CONFLUENCE = 2.67
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 18.99 7.54 4.852 5.58
2 2.67 7.61 4.821 0.85
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 21.63 7.54 4.852
2 21.53 7.61 4.821
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 21.63 Tc(MIN.) = 7.54
TOTAL AREA(ACRES) = 6.4
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1028.00 = 1396.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1033.00 TO NODE 1028.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.852
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6701
SUBAREA AREA(ACRES) = 0.99 SUBAREA RUNOFF(CFS) = 3.12
TOTAL AREA(ACRES) = 7.4 TOTAL RUNOFF(CFS) = 24.13
TC(MIN.) = 7.54
****************************************************************************
FLOW PROCESS FROM NODE 1028.00 TO NODE 1005.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 105.90 DOWNSTREAM(FEET) = 103.20
FLOW LENGTH(FEET) = 122.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 24.0 INCH PIPE IS 15.3 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 11.42
ESTIMATED PIPE DIAMETER(INCH) = 24.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 24.13
PIPE TRAVEL TIME(MIN.) = 0.18 Tc(MIN.) = 7.72
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1005.00 = 1518.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1028.00 TO NODE 1005.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 7.72
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 13 of 18
1000P100.RES
RAINFALL INTENSITY(INCH/HR) = 4.78
TOTAL STREAM AREA(ACRES) = 7.42
PEAK FLOW RATE(CFS) AT CONFLUENCE = 24.13
****************************************************************************
FLOW PROCESS FROM NODE 1036.00 TO NODE 1037.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 118.00
UPSTREAM ELEVATION(FEET) = 113.30
DOWNSTREAM ELEVATION(FEET) = 111.70
ELEVATION DIFFERENCE(FEET) = 1.60
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.277
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 73.56
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.461
SUBAREA RUNOFF(CFS) = 0.43
TOTAL AREA(ACRES) = 0.12 TOTAL RUNOFF(CFS) = 0.43
****************************************************************************
FLOW PROCESS FROM NODE 1037.00 TO NODE 1040.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 111.70 DOWNSTREAM ELEVATION(FEET) = 107.90
STREET LENGTH(FEET) = 369.50 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 1.26
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.27
HALFSTREET FLOOD WIDTH(FEET) = 7.78
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.90
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.51
STREET FLOW TRAVEL TIME(MIN.) = 3.23 Tc(MIN.) = 9.51
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.177
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 0.61 SUBAREA RUNOFF(CFS) = 1.66
TOTAL AREA(ACRES) = 0.7 PEAK FLOW RATE(CFS) = 1.98
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.30 HALFSTREET FLOOD WIDTH(FEET) = 9.59
FLOW VELOCITY(FEET/SEC.) = 2.10 DEPTH*VELOCITY(FT*FT/SEC.) = 0.63
LONGEST FLOWPATH FROM NODE 1036.00 TO NODE 1040.00 = 487.50 FEET.
****************************************************************************
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 14 of 18
1000P100.RES
FLOW PROCESS FROM NODE 1039.00 TO NODE 1040.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.177
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6500
SUBAREA AREA(ACRES) = 0.80 SUBAREA RUNOFF(CFS) = 2.17
TOTAL AREA(ACRES) = 1.5 TOTAL RUNOFF(CFS) = 4.15
TC(MIN.) = 9.51
****************************************************************************
FLOW PROCESS FROM NODE 1040.00 TO NODE 1005.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 105.50 DOWNSTREAM(FEET) = 103.47
FLOW LENGTH(FEET) = 201.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 8.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.50
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 4.15
PIPE TRAVEL TIME(MIN.) = 0.61 Tc(MIN.) = 10.12
LONGEST FLOWPATH FROM NODE 1036.00 TO NODE 1005.00 = 688.50 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1040.00 TO NODE 1005.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 10.12
RAINFALL INTENSITY(INCH/HR) = 4.01
TOTAL STREAM AREA(ACRES) = 1.53
PEAK FLOW RATE(CFS) AT CONFLUENCE = 4.15
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 24.13 7.72 4.780 7.42
2 4.15 10.12 4.013 1.53
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 27.29 7.72 4.780
2 24.41 10.12 4.013
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 27.29 Tc(MIN.) = 7.72
TOTAL AREA(ACRES) = 8.9
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1005.00 = 1518.70 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1005.00 TO NODE 1035.00 IS CODE = 31
----------------------------------------------------------------------------
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 15 of 18
1000P100.RES
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 103.37 DOWNSTREAM(FEET) = 101.31
FLOW LENGTH(FEET) = 205.50 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 20.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.61
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 27.29
PIPE TRAVEL TIME(MIN.) = 0.40 Tc(MIN.) = 8.11
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1035.00 = 1724.20 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1041.00 TO NODE 1035.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.627
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6659
SUBAREA AREA(ACRES) = 0.42 SUBAREA RUNOFF(CFS) = 1.26
TOTAL AREA(ACRES) = 9.4 TOTAL RUNOFF(CFS) = 28.87
TC(MIN.) = 8.11
****************************************************************************
FLOW PROCESS FROM NODE 1035.00 TO NODE 1038.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 101.21 DOWNSTREAM(FEET) = 100.70
FLOW LENGTH(FEET) = 32.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 27.0 INCH PIPE IS 17.6 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 10.54
ESTIMATED PIPE DIAMETER(INCH) = 27.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 28.87
PIPE TRAVEL TIME(MIN.) = 0.05 Tc(MIN.) = 8.16
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1038.00 = 1756.20 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1035.00 TO NODE 1038.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 8.16
RAINFALL INTENSITY(INCH/HR) = 4.61
TOTAL STREAM AREA(ACRES) = 9.37
PEAK FLOW RATE(CFS) AT CONFLUENCE = 28.87
****************************************************************************
FLOW PROCESS FROM NODE 1006.00 TO NODE 1007.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 142.80
UPSTREAM ELEVATION(FEET) = 113.10
DOWNSTREAM ELEVATION(FEET) = 111.00
ELEVATION DIFFERENCE(FEET) = 2.10
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 16 of 18
1000P100.RES
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.157
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 74.71
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.529
SUBAREA RUNOFF(CFS) = 0.58
TOTAL AREA(ACRES) = 0.16 TOTAL RUNOFF(CFS) = 0.58
****************************************************************************
FLOW PROCESS FROM NODE 1007.00 TO NODE 1008.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 111.00 DOWNSTREAM ELEVATION(FEET) = 109.00
STREET LENGTH(FEET) = 580.00 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.14
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.35
HALFSTREET FLOOD WIDTH(FEET) = 12.59
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.40
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.49
STREET FLOW TRAVEL TIME(MIN.) = 6.93 Tc(MIN.) = 13.08
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.400
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 1.38 SUBAREA RUNOFF(CFS) = 3.05
TOTAL AREA(ACRES) = 1.5 PEAK FLOW RATE(CFS) = 3.40
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.39 HALFSTREET FLOOD WIDTH(FEET) = 14.50
FLOW VELOCITY(FEET/SEC.) = 1.52 DEPTH*VELOCITY(FT*FT/SEC.) = 0.59
LONGEST FLOWPATH FROM NODE 1006.00 TO NODE 1008.00 = 722.80 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1008.00 TO NODE 1038.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 100.91 DOWNSTREAM(FEET) = 100.70
FLOW LENGTH(FEET) = 21.14 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 9.7 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.02
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3.40
PIPE TRAVEL TIME(MIN.) = 0.07 Tc(MIN.) = 13.15
LONGEST FLOWPATH FROM NODE 1006.00 TO NODE 1038.00 = 743.94 FEET.
****************************************************************************
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 17 of 18
1000P100.RES
FLOW PROCESS FROM NODE 1008.00 TO NODE 1038.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 13.15
RAINFALL INTENSITY(INCH/HR) = 3.39
TOTAL STREAM AREA(ACRES) = 1.54
PEAK FLOW RATE(CFS) AT CONFLUENCE = 3.40
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 28.87 8.16 4.609 9.37
2 3.40 13.15 3.389 1.54
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 30.98 8.16 4.609
2 24.63 13.15 3.389
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 30.98 Tc(MIN.) = 8.16
TOTAL AREA(ACRES) = 10.9
LONGEST FLOWPATH FROM NODE 1009.00 TO NODE 1038.00 = 1756.20 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 10.9 TC(MIN.) = 8.16
PEAK FLOW RATE(CFS) = 30.98
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 11:40:55 AM AM Modified: 6/14/2022 9:46:31 AM AM Page 18 of 18
RATIONAL METHOD HYDROGRAPH PROGRAM
COPYRIGHT 1992, 2001 RICK ENGINEERING COMPANY
RUN DATE 6/14/2022
HYDROGRAPH FILE NAME System 1000
TIME OF CONCENTRATION 8 MIN.
6 HOUR RAINFALL 2.4 INCHES
BASIN AREA 10.9 ACRES
RUNOFF COEFFICIENT 0.66
PEAK DISCHARGE 31 CFS
TIME (MIN) = 0 DISCHARGE (CFS) = 0
TIME (MIN) = 8 DISCHARGE (CFS) = 1
TIME (MIN) = 16 DISCHARGE (CFS) = 1
TIME (MIN) = 24 DISCHARGE (CFS) = 1.1
TIME (MIN) = 32 DISCHARGE (CFS) = 1.1
TIME (MIN) = 40 DISCHARGE (CFS) = 1.1
TIME (MIN) = 48 DISCHARGE (CFS) = 1.2
TIME (MIN) = 56 DISCHARGE (CFS) = 1.2
TIME (MIN) = 64 DISCHARGE (CFS) = 1.2
TIME (MIN) = 72 DISCHARGE (CFS) = 1.3
TIME (MIN) = 80 DISCHARGE (CFS) = 1.3
TIME (MIN) = 88 DISCHARGE (CFS) = 1.3
TIME (MIN) = 96 DISCHARGE (CFS) = 1.4
TIME (MIN) = 104 DISCHARGE (CFS) = 1.4
TIME (MIN) = 112 DISCHARGE (CFS) = 1.5
TIME (MIN) = 120 DISCHARGE (CFS) = 1.6
TIME (MIN) = 128 DISCHARGE (CFS) = 1.6
TIME (MIN) = 136 DISCHARGE (CFS) = 1.7
TIME (MIN) = 144 DISCHARGE (CFS) = 1.8
TIME (MIN) = 152 DISCHARGE (CFS) = 1.9
TIME (MIN) = 160 DISCHARGE (CFS) = 2
TIME (MIN) = 168 DISCHARGE (CFS) = 2.1
TIME (MIN) = 176 DISCHARGE (CFS) = 2.2
TIME (MIN) = 184 DISCHARGE (CFS) = 2.5
TIME (MIN) = 192 DISCHARGE (CFS) = 2.6
TIME (MIN) = 200 DISCHARGE (CFS) = 3
TIME (MIN) = 208 DISCHARGE (CFS) = 3.3
TIME (MIN) = 216 DISCHARGE (CFS) = 4
TIME (MIN) = 224 DISCHARGE (CFS) = 4.5
TIME (MIN) = 232 DISCHARGE (CFS) = 6.7
TIME (MIN) = 240 DISCHARGE (CFS) = 12
TIME (MIN) = 248 DISCHARGE (CFS) = 31
TIME (MIN) = 256 DISCHARGE (CFS) = 5.3
TIME (MIN) = 264 DISCHARGE (CFS) = 3.6
TIME (MIN) = 272 DISCHARGE (CFS) = 2.8
TIME (MIN) = 280 DISCHARGE (CFS) = 2.3
TIME (MIN) = 288 DISCHARGE (CFS) = 2
TIME (MIN) = 296 DISCHARGE (CFS) = 1.8
TIME (MIN) = 304 DISCHARGE (CFS) = 1.6
TIME (MIN) = 312 DISCHARGE (CFS) = 1.5
TIME (MIN) = 320 DISCHARGE (CFS) = 1.4
TIME (MIN) = 328 DISCHARGE (CFS) = 1.3
TIME (MIN) = 336 DISCHARGE (CFS) = 1.2
TIME (MIN) = 344 DISCHARGE (CFS) = 1.2
TIME (MIN) = 352 DISCHARGE (CFS) = 1.1
TIME (MIN) = 360 DISCHARGE (CFS) = 1.1
TIME (MIN) = 368 DISCHARGE (CFS) = 0
1100P100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO - PROPOSED CONDITION 4409 *
* SYSTEM 1100 (INCLUDING SYS1000) *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: 1100P100.DAT
TIME/DATE OF STUDY: 11:22 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 12.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 14.5 8.0 0.018/0.018/0.020 0.50 1.50 0.0313 0.125 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 1100.00 TO NODE 1101.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 143.00
UPSTREAM ELEVATION(FEET) = 116.80
DOWNSTREAM ELEVATION(FEET) = 115.00
ELEVATION DIFFERENCE(FEET) = 1.80
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.392
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 1 of 7
1100P100.RES
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 72.59
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.397
SUBAREA RUNOFF(CFS) = 0.63
TOTAL AREA(ACRES) = 0.18 TOTAL RUNOFF(CFS) = 0.63
****************************************************************************
FLOW PROCESS FROM NODE 1101.00 TO NODE 1102.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 115.50 DOWNSTREAM ELEVATION(FEET) = 111.10
STREET LENGTH(FEET) = 398.00 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 1
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.35
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.31
HALFSTREET FLOOD WIDTH(FEET) = 10.22
AVERAGE FLOW VELOCITY(FEET/SEC.) = 2.23
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.69
STREET FLOW TRAVEL TIME(MIN.) = 2.98 Tc(MIN.) = 9.37
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.217
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 1.24 SUBAREA RUNOFF(CFS) = 3.40
TOTAL AREA(ACRES) = 1.4 PEAK FLOW RATE(CFS) = 3.89
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.36 HALFSTREET FLOOD WIDTH(FEET) = 12.66
FLOW VELOCITY(FEET/SEC.) = 2.51 DEPTH*VELOCITY(FT*FT/SEC.) = 0.89
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1102.00 = 541.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1102.00 TO NODE 1103.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 109.00 DOWNSTREAM(FEET) = 108.70
FLOW LENGTH(FEET) = 22.60 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 9.5 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 5.81
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 3.89
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 9.43
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1103.00 = 563.60 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1104.00 TO NODE 1103.00 IS CODE = 81
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 2 of 7
1100P100.RES
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.199
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6500
SUBAREA AREA(ACRES) = 1.05 SUBAREA RUNOFF(CFS) = 2.87
TOTAL AREA(ACRES) = 2.5 TOTAL RUNOFF(CFS) = 6.74
TC(MIN.) = 9.43
****************************************************************************
FLOW PROCESS FROM NODE 1103.00 TO NODE 1105.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 109.00 DOWNSTREAM(FEET) = 107.70
FLOW LENGTH(FEET) = 229.70 MANNING'S N = 0.013
DEPTH OF FLOW IN 18.0 INCH PIPE IS 13.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 4.92
ESTIMATED PIPE DIAMETER(INCH) = 18.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 6.74
PIPE TRAVEL TIME(MIN.) = 0.78 Tc(MIN.) = 10.21
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1105.00 = 793.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1106.00 TO NODE 1105.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.989
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6500
SUBAREA AREA(ACRES) = 0.45 SUBAREA RUNOFF(CFS) = 1.17
TOTAL AREA(ACRES) = 2.9 TOTAL RUNOFF(CFS) = 7.57
TC(MIN.) = 10.21
****************************************************************************
FLOW PROCESS FROM NODE 1105.00 TO NODE 1107.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 107.70 DOWNSTREAM(FEET) = 100.90
FLOW LENGTH(FEET) = 230.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 9.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 9.54
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 7.57
PIPE TRAVEL TIME(MIN.) = 0.40 Tc(MIN.) = 10.61
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1107.00 = 1023.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1005.00 TO NODE 1007.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 10.61
RAINFALL INTENSITY(INCH/HR) = 3.89
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 3 of 7
1100P100.RES
TOTAL STREAM AREA(ACRES) = 2.92
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.57
****************************************************************************
FLOW PROCESS FROM NODE 1108.00 TO NODE 1109.00 IS CODE = 21
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
INITIAL SUBAREA FLOW-LENGTH(FEET) = 138.00
UPSTREAM ELEVATION(FEET) = 112.50
DOWNSTREAM ELEVATION(FEET) = 111.00
ELEVATION DIFFERENCE(FEET) = 1.50
URBAN SUBAREA OVERLAND TIME OF FLOW(MIN.) = 6.632
WARNING: INITIAL SUBAREA FLOW PATH LENGTH IS GREATER THAN
THE MAXIMUM OVERLAND FLOW LENGTH = 70.87
(Reference: Table 3-1B of Hydrology Manual)
THE MAXIMUM OVERLAND FLOW LENGTH IS USED IN Tc CALCULATION!
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.270
SUBAREA RUNOFF(CFS) = 0.55
TOTAL AREA(ACRES) = 0.16 TOTAL RUNOFF(CFS) = 0.55
****************************************************************************
FLOW PROCESS FROM NODE 1109.00 TO NODE 1107.00 IS CODE = 62
----------------------------------------------------------------------------
>>>>>COMPUTE STREET FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>(STREET TABLE SECTION # 1 USED)<<<<<
============================================================================
UPSTREAM ELEVATION(FEET) = 111.00 DOWNSTREAM ELEVATION(FEET) = 109.00
STREET LENGTH(FEET) = 191.00 CURB HEIGHT(INCHES) = 6.0
STREET HALFWIDTH(FEET) = 14.50
DISTANCE FROM CROWN TO CROSSFALL GRADEBREAK(FEET) = 8.00
INSIDE STREET CROSSFALL(DECIMAL) = 0.018
OUTSIDE STREET CROSSFALL(DECIMAL) = 0.018
SPECIFIED NUMBER OF HALFSTREETS CARRYING RUNOFF = 2
STREET PARKWAY CROSSFALL(DECIMAL) = 0.020
Manning's FRICTION FACTOR for Streetflow Section(curb-to-curb) = 0.0150
Manning's FRICTION FACTOR for Back-of-Walk Flow Section = 0.0200
**TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.92
STREETFLOW MODEL RESULTS USING ESTIMATED FLOW:
STREET FLOW DEPTH(FEET) = 0.28
HALFSTREET FLOOD WIDTH(FEET) = 8.34
AVERAGE FLOW VELOCITY(FEET/SEC.) = 1.97
PRODUCT OF DEPTH&VELOCITY(FT*FT/SEC.) = 0.55
STREET FLOW TRAVEL TIME(MIN.) = 1.62 Tc(MIN.) = 8.25
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.578
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.650
SUBAREA AREA(ACRES) = 1.59 SUBAREA RUNOFF(CFS) = 4.73
TOTAL AREA(ACRES) = 1.8 PEAK FLOW RATE(CFS) = 5.21
END OF SUBAREA STREET FLOW HYDRAULICS:
DEPTH(FEET) = 0.32 HALFSTREET FLOOD WIDTH(FEET) = 10.78
FLOW VELOCITY(FEET/SEC.) = 2.25 DEPTH*VELOCITY(FT*FT/SEC.) = 0.72
LONGEST FLOWPATH FROM NODE 1108.00 TO NODE 1107.00 = 329.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1110.00 TO NODE 1107.00 IS CODE = 81
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 4 of 7
1100P100.RES
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.578
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .9000
AREA-AVERAGE RUNOFF COEFFICIENT = 0.7029
SUBAREA AREA(ACRES) = 0.47 SUBAREA RUNOFF(CFS) = 1.94
TOTAL AREA(ACRES) = 2.2 TOTAL RUNOFF(CFS) = 7.14
TC(MIN.) = 8.25
****************************************************************************
FLOW PROCESS FROM NODE 1111.00 TO NODE 1107.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.578
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .4500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6820
SUBAREA AREA(ACRES) = 0.20 SUBAREA RUNOFF(CFS) = 0.41
TOTAL AREA(ACRES) = 2.4 TOTAL RUNOFF(CFS) = 7.56
TC(MIN.) = 8.25
****************************************************************************
FLOW PROCESS FROM NODE 1111.00 TO NODE 1107.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 8.25
RAINFALL INTENSITY(INCH/HR) = 4.58
TOTAL STREAM AREA(ACRES) = 2.42
PEAK FLOW RATE(CFS) AT CONFLUENCE = 7.56
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 7.57 10.61 3.891 2.92
2 7.56 8.25 4.578 2.42
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 13.44 8.25 4.578
2 13.99 10.61 3.891
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 13.99 Tc(MIN.) = 10.61
TOTAL AREA(ACRES) = 5.3
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1107.00 = 1023.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1107.00 TO NODE 1055.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 5 of 7
1100P100.RES
ELEVATION DATA: UPSTREAM(FEET) = 105.50 DOWNSTREAM(FEET) = 105.00
FLOW LENGTH(FEET) = 8.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 11.0 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 14.49
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 13.99
PIPE TRAVEL TIME(MIN.) = 0.01 Tc(MIN.) = 10.62
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1055.00 = 1031.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1112.00 TO NODE 1055.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.889
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .4500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.6617
SUBAREA AREA(ACRES) = 0.07 SUBAREA RUNOFF(CFS) = 0.12
TOTAL AREA(ACRES) = 5.4 TOTAL RUNOFF(CFS) = 13.99
TC(MIN.) = 10.62
NOTE: PEAK FLOW RATE DEFAULTED TO UPSTREAM VALUE
****************************************************************************
FLOW PROCESS FROM NODE 1038.00 TO NODE 1055.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 1 ARE:
TIME OF CONCENTRATION(MIN.) = 10.62
RAINFALL INTENSITY(INCH/HR) = 3.89
TOTAL STREAM AREA(ACRES) = 5.41
PEAK FLOW RATE(CFS) AT CONFLUENCE = 13.99
****************************************************************************
FLOW PROCESS FROM NODE 1038.00 TO NODE 1038.00 IS CODE = 7
----------------------------------------------------------------------------
>>>>>USER SPECIFIED HYDROLOGY INFORMATION AT NODE<<<<<
============================================================================
USER-SPECIFIED VALUES ARE AS FOLLOWS:
TC(MIN) = 68.20 RAIN INTENSITY(INCH/HOUR) = 1.17
TOTAL AREA(ACRES) = 10.90 TOTAL RUNOFF(CFS) = 1.55
****************************************************************************
FLOW PROCESS FROM NODE 1038.00 TO NODE 1055.00 IS CODE = 1
----------------------------------------------------------------------------
>>>>>DESIGNATE INDEPENDENT STREAM FOR CONFLUENCE<<<<<
>>>>>AND COMPUTE VARIOUS CONFLUENCED STREAM VALUES<<<<<
============================================================================
TOTAL NUMBER OF STREAMS = 2
CONFLUENCE VALUES USED FOR INDEPENDENT STREAM 2 ARE:
TIME OF CONCENTRATION(MIN.) = 68.20
RAINFALL INTENSITY(INCH/HR) = 1.17
TOTAL STREAM AREA(ACRES) = 10.90
PEAK FLOW RATE(CFS) AT CONFLUENCE = 1.55
** CONFLUENCE DATA **
STREAM RUNOFF Tc INTENSITY AREA
NUMBER (CFS) (MIN.) (INCH/HOUR) (ACRE)
1 13.99 10.62 3.889 5.41
2 1.55 68.20 1.172 10.90
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 6 of 7
1100P100.RES
RAINFALL INTENSITY AND TIME OF CONCENTRATION RATIO
CONFLUENCE FORMULA USED FOR 2 STREAMS.
** PEAK FLOW RATE TABLE **
STREAM RUNOFF Tc INTENSITY
NUMBER (CFS) (MIN.) (INCH/HOUR)
1 14.24 10.62 3.889
2 5.77 68.20 1.172
COMPUTED CONFLUENCE ESTIMATES ARE AS FOLLOWS:
PEAK FLOW RATE(CFS) = 14.24 Tc(MIN.) = 10.62
TOTAL AREA(ACRES) = 16.3
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1055.00 = 1031.30 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1055.00 TO NODE 1056.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 98.28 DOWNSTREAM(FEET) = 98.00
FLOW LENGTH(FEET) = 28.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 21.0 INCH PIPE IS 15.9 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.29
ESTIMATED PIPE DIAMETER(INCH) = 21.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 14.24
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 10.69
LONGEST FLOWPATH FROM NODE 1100.00 TO NODE 1056.00 = 1059.30 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 16.3 TC(MIN.) = 10.69
PEAK FLOW RATE(CFS) = 14.24
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 11:38:32 AM AM Modified: 6/14/2022 11:22:34 AM AM Page 7 of 7
1200P100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO 4409 *
* SYSTEM 1200 *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: 1200P100.DAT
TIME/DATE OF STUDY: 12:06 06/17/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 12.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.50 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
Printed: 6/17/2022 12:10:18 PM PM Modified: 6/17/2022 12:06:54 PM PM Page 1 of 1
1300P100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* NAKANO 4409 *
* SYSTEM 1300 *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: 1300P100.DAT
TIME/DATE OF STUDY: 12:05 06/17/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 12.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 1300.00 TO NODE 1301.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 0.11
TOTAL AREA(ACRES) = 0.03 TOTAL RUNOFF(CFS) = 0.11
Printed: 6/17/2022 12:09:55 PM PM Modified: 6/17/2022 12:05:21 PM PM Page 1 of 3
1300P100.RES
****************************************************************************
FLOW PROCESS FROM NODE 1301.00 TO NODE 1302.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 186.00 DOWNSTREAM(FEET) = 113.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 717.00 CHANNEL SLOPE = 0.1018
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 2.000
MANNING'S FACTOR = 0.030 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.322
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.45
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.97
AVERAGE FLOW DEPTH(FEET) = 0.08 TRAVEL TIME(MIN.) = 4.02
Tc(MIN.) = 9.02
SUBAREA AREA(ACRES) = 1.75 SUBAREA RUNOFF(CFS) = 4.54
AREA-AVERAGE RUNOFF COEFFICIENT = 0.600
TOTAL AREA(ACRES) = 1.8 PEAK FLOW RATE(CFS) = 4.62
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.12 FLOW VELOCITY(FEET/SEC.) = 3.78
LONGEST FLOWPATH FROM NODE 1300.00 TO NODE 1302.00 = 717.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1302.00 TO NODE 1303.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 112.00 DOWNSTREAM(FEET) = 111.50
FLOW LENGTH(FEET) = 24.60 MANNING'S N = 0.013
DEPTH OF FLOW IN 12.0 INCH PIPE IS 9.2 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 7.17
ESTIMATED PIPE DIAMETER(INCH) = 12.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 4.62
PIPE TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 9.08
LONGEST FLOWPATH FROM NODE 1300.00 TO NODE 1303.00 = 741.60 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1303.00 TO NODE 1304.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 111.50 DOWNSTREAM(FEET) = 106.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 345.00 CHANNEL SLOPE = 0.0159
CHANNEL BASE(FEET) = 5.00 "Z" FACTOR = 2.500
MANNING'S FACTOR = 0.013 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 3.972
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 5.73
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 4.77
AVERAGE FLOW DEPTH(FEET) = 0.22 TRAVEL TIME(MIN.) = 1.20
Tc(MIN.) = 10.28
SUBAREA AREA(ACRES) = 0.93 SUBAREA RUNOFF(CFS) = 2.22
AREA-AVERAGE RUNOFF COEFFICIENT = 0.600
TOTAL AREA(ACRES) = 2.7 PEAK FLOW RATE(CFS) = 6.46
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.23 FLOW VELOCITY(FEET/SEC.) = 5.00
Printed: 6/17/2022 12:09:55 PM PM Modified: 6/17/2022 12:05:21 PM PM Page 2 of 3
1300P100.RES
LONGEST FLOWPATH FROM NODE 1300.00 TO NODE 1304.00 = 1086.60 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1304.00 TO NODE 1306.00 IS CODE = 31
----------------------------------------------------------------------------
>>>>>COMPUTE PIPE-FLOW TRAVEL TIME THRU SUBAREA<<<<<
>>>>>USING COMPUTER-ESTIMATED PIPESIZE (NON-PRESSURE FLOW)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 106.00 DOWNSTREAM(FEET) = 104.00
FLOW LENGTH(FEET) = 90.00 MANNING'S N = 0.013
DEPTH OF FLOW IN 15.0 INCH PIPE IS 9.1 INCHES
PIPE-FLOW VELOCITY(FEET/SEC.) = 8.25
ESTIMATED PIPE DIAMETER(INCH) = 15.00 NUMBER OF PIPES = 1
PIPE-FLOW(CFS) = 6.46
PIPE TRAVEL TIME(MIN.) = 0.18 Tc(MIN.) = 10.46
LONGEST FLOWPATH FROM NODE 1300.00 TO NODE 1306.00 = 1176.60 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 2.7 TC(MIN.) = 10.46
PEAK FLOW RATE(CFS) = 6.46
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 12:09:55 PM PM Modified: 6/17/2022 12:05:21 PM PM Page 3 of 3
1600P100.RES
____________________________________________________________________________
****************************************************************************
RATIONAL METHOD HYDROLOGY COMPUTER PROGRAM PACKAGE
Reference: SAN DIEGO COUNTY FLOOD CONTROL DISTRICT
2003,1985,1981 HYDROLOGY MANUAL
(c) Copyright 1982-2016 Advanced Engineering Software (aes)
Ver. 23.0 Release Date: 07/01/2016 License ID 1509
Analysis prepared by:
************************** DESCRIPTION OF STUDY **************************
* 4409 NAKANO *
* SYSTEM 1600 - PROPOSED CONDITIONS *
* 100 YEAR STORM EVENT *
**************************************************************************
FILE NAME: 1600P100.DAT
TIME/DATE OF STUDY: 15:38 06/14/2022
----------------------------------------------------------------------------
USER SPECIFIED HYDROLOGY AND HYDRAULIC MODEL INFORMATION:
----------------------------------------------------------------------------
2003 SAN DIEGO MANUAL CRITERIA
USER SPECIFIED STORM EVENT(YEAR) = 100.00
6-HOUR DURATION PRECIPITATION (INCHES) = 2.400
SPECIFIED MINIMUM PIPE SIZE(INCH) = 18.00
SPECIFIED PERCENT OF GRADIENTS(DECIMAL) TO USE FOR FRICTION SLOPE = 0.95
SAN DIEGO HYDROLOGY MANUAL "C"-VALUES USED FOR RATIONAL METHOD
*CITY OF CHULA VISTA TIME-OF-CONCENTRATION MODEL SELECTED.*
(BASED ON 07/2002 ADOPTED MANUAL)
NOTE: USE MODIFIED RATIONAL METHOD PROCEDURES FOR CONFLUENCE ANALYSIS
*USER-DEFINED STREET-SECTIONS FOR COUPLED PIPEFLOW AND STREETFLOW MODEL*
HALF- CROWN TO STREET-CROSSFALL: CURB GUTTER-GEOMETRIES: MANNING
WIDTH CROSSFALL IN- / OUT-/PARK- HEIGHT WIDTH LIP HIKE FACTOR
NO. (FT) (FT) SIDE / SIDE/ WAY (FT) (FT) (FT) (FT) (n)
=== ===== ========= ================= ====== ===== ====== ===== =======
1 30.0 20.0 0.018/0.018/0.020 0.67 2.00 0.0313 0.167 0.0150
GLOBAL STREET FLOW-DEPTH CONSTRAINTS:
1. Relative Flow-Depth = 0.00 FEET
as (Maximum Allowable Street Flow Depth) - (Top-of-Curb)
2. (Depth)*(Velocity) Constraint = 6.0 (FT*FT/S)
*SIZE PIPE WITH A FLOW CAPACITY GREATER THAN
OR EQUAL TO THE UPSTREAM TRIBUTARY PIPE.*
****************************************************************************
FLOW PROCESS FROM NODE 1600.00 TO NODE 1601.00 IS CODE = 22
----------------------------------------------------------------------------
>>>>>RATIONAL METHOD INITIAL SUBAREA ANALYSIS<<<<<
============================================================================
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
USER SPECIFIED Tc(MIN.) = 5.000
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 6.323
SUBAREA RUNOFF(CFS) = 0.49
TOTAL AREA(ACRES) = 0.13 TOTAL RUNOFF(CFS) = 0.49
Printed: 6/17/2022 11:39:52 AM AM Modified: 6/14/2022 3:38:27 PM PM Page 1 of 3
1600P100.RES
****************************************************************************
FLOW PROCESS FROM NODE 1601.00 TO NODE 1602.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 178.00 DOWNSTREAM(FEET) = 140.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 126.00 CHANNEL SLOPE = 0.3016
CHANNEL BASE(FEET) = 10.00 "Z" FACTOR = 50.000
MANNING'S FACTOR = 0.045 MAXIMUM DEPTH(FEET) = 2.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 5.763
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .6000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 2.37
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 2.71
AVERAGE FLOW DEPTH(FEET) = 0.07 TRAVEL TIME(MIN.) = 0.77
Tc(MIN.) = 5.77
SUBAREA AREA(ACRES) = 1.09 SUBAREA RUNOFF(CFS) = 3.77
AREA-AVERAGE RUNOFF COEFFICIENT = 0.600
TOTAL AREA(ACRES) = 1.2 PEAK FLOW RATE(CFS) = 4.22
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.09 FLOW VELOCITY(FEET/SEC.) = 3.04
LONGEST FLOWPATH FROM NODE 1600.00 TO NODE 1602.00 = 790.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1602.00 TO NODE 1605.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 141.00 DOWNSTREAM(FEET) = 116.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 49.00 CHANNEL SLOPE = 0.5102
CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 3.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 0.50
CHANNEL FLOW THRU SUBAREA(CFS) = 4.22
FLOW VELOCITY(FEET/SEC.) = 13.61 FLOW DEPTH(FEET) = 0.09
TRAVEL TIME(MIN.) = 0.06 Tc(MIN.) = 5.83
LONGEST FLOWPATH FROM NODE 1600.00 TO NODE 1605.00 = 839.00 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1605.00 TO NODE 1607.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 118.00 DOWNSTREAM(FEET) = 116.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 430.80 CHANNEL SLOPE = 0.0046
CHANNEL BASE(FEET) = 1.00 "Z" FACTOR = 2.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 1.00
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.735
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5500
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 5.42
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 3.60
AVERAGE FLOW DEPTH(FEET) = 0.65 TRAVEL TIME(MIN.) = 2.00
Tc(MIN.) = 7.83
SUBAREA AREA(ACRES) = 0.92 SUBAREA RUNOFF(CFS) = 2.40
AREA-AVERAGE RUNOFF COEFFICIENT = 0.579
TOTAL AREA(ACRES) = 2.1 PEAK FLOW RATE(CFS) = 5.86
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.68 FLOW VELOCITY(FEET/SEC.) = 3.64
Printed: 6/17/2022 11:39:52 AM AM Modified: 6/14/2022 3:38:27 PM PM Page 2 of 3
1600P100.RES
LONGEST FLOWPATH FROM NODE 1600.00 TO NODE 1607.00 = 1269.80 FEET.
****************************************************************************
FLOW PROCESS FROM NODE 1608.00 TO NODE 1607.00 IS CODE = 81
----------------------------------------------------------------------------
>>>>>ADDITION OF SUBAREA TO MAINLINE PEAK FLOW<<<<<
============================================================================
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.735
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5500
AREA-AVERAGE RUNOFF COEFFICIENT = 0.5745
SUBAREA AREA(ACRES) = 0.35 SUBAREA RUNOFF(CFS) = 0.91
TOTAL AREA(ACRES) = 2.5 TOTAL RUNOFF(CFS) = 6.77
TC(MIN.) = 7.83
****************************************************************************
FLOW PROCESS FROM NODE 1609.00 TO NODE 1609.00 IS CODE = 51
----------------------------------------------------------------------------
>>>>>COMPUTE TRAPEZOIDAL CHANNEL FLOW<<<<<
>>>>>TRAVELTIME THRU SUBAREA (EXISTING ELEMENT)<<<<<
============================================================================
ELEVATION DATA: UPSTREAM(FEET) = 116.00 DOWNSTREAM(FEET) = 98.00
CHANNEL LENGTH THRU SUBAREA(FEET) = 664.00 CHANNEL SLOPE = 0.0271
CHANNEL BASE(FEET) = 3.00 "Z" FACTOR = 3.000
MANNING'S FACTOR = 0.015 MAXIMUM DEPTH(FEET) = 0.50
100 YEAR RAINFALL INTENSITY(INCH/HOUR) = 4.156
*USER SPECIFIED(SUBAREA):
USER-SPECIFIED RUNOFF COEFFICIENT = .5000
TRAVEL TIME COMPUTED USING ESTIMATED FLOW(CFS) = 7.63
TRAVEL TIME THRU SUBAREA BASED ON VELOCITY(FEET/SEC.) = 6.31
AVERAGE FLOW DEPTH(FEET) = 0.31 TRAVEL TIME(MIN.) = 1.75
Tc(MIN.) = 9.58
SUBAREA AREA(ACRES) = 0.82 SUBAREA RUNOFF(CFS) = 1.70
AREA-AVERAGE RUNOFF COEFFICIENT = 0.556
TOTAL AREA(ACRES) = 3.3 PEAK FLOW RATE(CFS) = 7.65
END OF SUBAREA CHANNEL FLOW HYDRAULICS:
DEPTH(FEET) = 0.31 FLOW VELOCITY(FEET/SEC.) = 6.33
LONGEST FLOWPATH FROM NODE 1600.00 TO NODE 1609.00 = 1933.80 FEET.
============================================================================
END OF STUDY SUMMARY:
TOTAL AREA(ACRES) = 3.3 TC(MIN.) = 9.58
PEAK FLOW RATE(CFS) = 7.65
============================================================================
============================================================================
END OF RATIONAL METHOD ANALYSIS
Printed: 6/17/2022 11:39:52 AM AM Modified: 6/14/2022 3:38:27 PM PM Page 3 of 3
APPENDIX 4
Hydraulic Calculations
To be completed during Final Engineering
APPENDIX 5
Preliminary Detention Analysis
Detention Vault
Project Summary
System 1000Title
PDCEngineer
PDCCompany
6/17/2022Date
Notes
Page 1 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Table of Contents
44Pond Inflow Summary
43Level Pool Pond Routing Summary
1 (IN)
41Elevation-Volume-Flow Table (Pond)
1
37Outlet Input DataOutlet#1
36Volume Equations
35Elevation-Area Volume Curve
1
20Time vs. Volume1
5Time vs. Elevation1 (OUT)
4Read HydrographCM-1
3Master Network Summary
2User Notifications
Detention Vault
Subsection: User Notifications
No user
notifications
generated.
User Notifications?
Page 2 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Subsection: Master Network Summary
Catchments Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ac-ft)
Return
Event
(years)
ScenarioLabel
31.00248.0001.4300EX10CM-1
Node Summary
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ac-ft)
Return
Event
(years)
ScenarioLabel
1.55308.0001.0340EX10O-1
Pond Summary
Maximum
Pond Storage
(ac-ft)
Maximum
Water
Surface
Elevation
(ft)
Peak Flow
(ft³/s)
Time to Peak
(min)
Hydrograph
Volume
(ac-ft)
Return
Event
(years)
ScenarioLabel
(N/A)(N/A)31.00248.0001.4300EX101 (IN)
1.224103.201.55308.0001.0340EX101 (OUT)
Page 3 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: CM-1
Return Event: 100 yearsSubsection: Read Hydrograph
ft³/s31.00Peak Discharge
min248.000Time to Peak
ac-ft1.430Hydrograph Volume
HYDROGRAPH ORDINATES (ft³/s)
Output Time Increment = 8.000 min
Time on left represents time for first value in each row.
Flow
(ft³/s)
Flow
(ft³/s)
Flow
(ft³/s)
Flow
(ft³/s)
Flow
(ft³/s)
Time
(min)
1.101.101.001.000.000.000
1.301.201.201.201.1040.000
1.501.401.401.301.3080.000
1.901.801.701.601.60120.000
2.602.502.202.102.00160.000
6.704.504.003.303.00200.000
2.803.605.3031.0012.00240.000
1.501.601.802.002.30280.000
1.101.201.201.301.40320.000
(N/A)(N/A)(N/A)0.001.10360.000
Page 4 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
99.0099.0099.0099.0099.000.000
99.0399.0299.0299.0199.015.000
99.0699.0599.0499.0499.0310.000
99.0999.0899.0799.0799.0615.000
99.1199.1199.1099.1099.0920.000
99.1499.1399.1399.1299.1225.000
99.1699.1699.1599.1599.1430.000
99.1899.1899.1799.1799.1635.000
99.2199.2099.2099.1999.1940.000
99.2399.2399.2299.2299.2145.000
99.2699.2599.2599.2499.2450.000
99.2899.2899.2799.2799.2655.000
99.3199.3199.3099.3099.2960.000
99.3499.3399.3399.3299.3265.000
99.3699.3699.3599.3599.3470.000
99.3999.3999.3899.3899.3775.000
99.4299.4299.4199.4099.4080.000
99.4599.4499.4499.4399.4385.000
99.4899.4799.4799.4699.4590.000
99.5199.5099.5099.4999.4895.000
99.5499.5399.5399.5299.51100.000
99.5799.5699.5699.5599.54105.000
99.6099.5999.5999.5899.57110.000
99.6399.6399.6299.6199.61115.000
99.6799.6699.6599.6599.64120.000
99.7099.7099.6999.6899.68125.000
99.7499.7399.7299.7299.71130.000
99.7899.7799.7699.7599.75135.000
99.8199.8199.8099.7999.78140.000
99.8599.8599.8499.8399.82145.000
99.9099.8999.8899.8799.86150.000
99.9499.9399.9299.9199.90155.000
99.9899.9799.9699.9699.95160.000
100.03100.02100.01100.0099.99165.000
100.07100.06100.06100.05100.04170.000
100.12100.11100.10100.09100.08175.000
100.18100.17100.15100.14100.13180.000
100.23100.22100.21100.20100.19185.000
100.29100.28100.27100.25100.24190.000
100.35100.34100.33100.31100.30195.000
Page 5 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
100.42100.41100.39100.38100.37200.000
100.49100.48100.46100.45100.43205.000
100.57100.56100.54100.52100.51210.000
100.66100.64100.63100.61100.59215.000
100.76100.74100.72100.70100.68220.000
100.88100.85100.83100.80100.78225.000
101.03101.00100.97100.94100.91230.000
101.26101.21101.16101.11101.07235.000
101.62101.53101.44101.37101.31240.000
102.25102.11101.97101.84101.73245.000
102.71102.65102.57102.48102.37250.000
102.85102.83102.81102.79102.76255.000
102.94102.93102.91102.89102.87260.000
103.02103.00102.99102.98102.96265.000
103.08103.07103.06103.04103.03270.000
103.13103.12103.11103.10103.09275.000
103.16103.15103.15103.14103.13280.000
103.18103.17103.17103.17103.16285.000
103.19103.19103.19103.18103.18290.000
103.20103.20103.20103.19103.19295.000
103.20103.20103.20103.20103.20300.000
103.20103.20103.20103.20103.20305.000
103.20103.20103.20103.20103.20310.000
103.20103.20103.20103.20103.20315.000
103.20103.20103.20103.20103.20320.000
103.19103.19103.19103.19103.20325.000
103.19103.19103.19103.19103.19330.000
103.18103.18103.19103.19103.19335.000
103.18103.18103.18103.18103.18340.000
103.18103.18103.18103.18103.18345.000
103.17103.17103.18103.18103.18350.000
103.17103.17103.17103.17103.17355.000
103.16103.17103.17103.17103.17360.000
103.14103.15103.15103.16103.16365.000
103.12103.13103.13103.14103.14370.000
103.11103.11103.12103.12103.12375.000
103.10103.10103.10103.10103.11380.000
103.09103.09103.09103.09103.10385.000
103.08103.08103.08103.08103.09390.000
103.07103.07103.07103.08103.08395.000
103.06103.06103.07103.07103.07400.000
Page 6 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
103.06103.06103.06103.06103.06405.000
103.05103.05103.05103.05103.06410.000
103.04103.05103.05103.05103.05415.000
103.04103.04103.04103.04103.04420.000
103.03103.03103.03103.04103.04425.000
103.03103.03103.03103.03103.03430.000
103.02103.02103.02103.02103.02435.000
103.01103.01103.02103.02103.02440.000
103.01103.01103.01103.01103.01445.000
103.00103.00103.00103.00103.01450.000
102.99103.00103.00103.00103.00455.000
102.99102.99102.99102.99102.99460.000
102.98102.98102.98102.99102.99465.000
102.98102.98102.98102.98102.98470.000
102.97102.97102.97102.97102.97475.000
102.96102.96102.97102.97102.97480.000
102.96102.96102.96102.96102.96485.000
102.95102.95102.95102.95102.96490.000
102.94102.95102.95102.95102.95495.000
102.94102.94102.94102.94102.94500.000
102.93102.93102.93102.94102.94505.000
102.93102.93102.93102.93102.93510.000
102.92102.92102.92102.92102.92515.000
102.91102.91102.92102.92102.92520.000
102.91102.91102.91102.91102.91525.000
102.90102.90102.90102.90102.91530.000
102.89102.90102.90102.90102.90535.000
102.89102.89102.89102.89102.89540.000
102.88102.88102.88102.89102.89545.000
102.88102.88102.88102.88102.88550.000
102.87102.87102.87102.87102.87555.000
102.86102.86102.87102.87102.87560.000
102.86102.86102.86102.86102.86565.000
102.85102.85102.85102.85102.86570.000
102.84102.85102.85102.85102.85575.000
102.84102.84102.84102.84102.84580.000
102.83102.83102.83102.84102.84585.000
102.83102.83102.83102.83102.83590.000
102.82102.82102.82102.82102.82595.000
102.81102.82102.82102.82102.82600.000
102.81102.81102.81102.81102.81605.000
Page 7 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
102.80102.80102.80102.81102.81610.000
102.80102.80102.80102.80102.80615.000
102.79102.79102.79102.79102.79620.000
102.78102.78102.79102.79102.79625.000
102.78102.78102.78102.78102.78630.000
102.77102.77102.77102.77102.78635.000
102.76102.77102.77102.77102.77640.000
102.76102.76102.76102.76102.76645.000
102.75102.75102.76102.76102.76650.000
102.75102.75102.75102.75102.75655.000
102.74102.74102.74102.74102.75660.000
102.73102.74102.74102.74102.74665.000
102.73102.73102.73102.73102.73670.000
102.72102.72102.72102.73102.73675.000
102.72102.72102.72102.72102.72680.000
102.71102.71102.71102.71102.71685.000
102.70102.71102.71102.71102.71690.000
102.70102.70102.70102.70102.70695.000
102.69102.69102.69102.70102.70700.000
102.69102.69102.69102.69102.69705.000
102.68102.68102.68102.68102.68710.000
102.67102.67102.68102.68102.68715.000
102.67102.67102.67102.67102.67720.000
102.66102.66102.66102.67102.67725.000
102.66102.66102.66102.66102.66730.000
102.65102.65102.65102.65102.65735.000
102.64102.64102.65102.65102.65740.000
102.64102.64102.64102.64102.64745.000
102.63102.63102.63102.64102.64750.000
102.63102.63102.63102.63102.63755.000
102.62102.62102.62102.62102.62760.000
102.61102.61102.62102.62102.62765.000
102.61102.61102.61102.61102.61770.000
102.60102.60102.60102.61102.61775.000
102.60102.60102.60102.60102.60780.000
102.59102.59102.59102.59102.59785.000
102.58102.58102.59102.59102.59790.000
102.58102.58102.58102.58102.58795.000
102.57102.57102.57102.58102.58800.000
102.57102.57102.57102.57102.57805.000
102.56102.56102.56102.56102.56810.000
Page 8 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
102.55102.55102.56102.56102.56815.000
102.55102.55102.55102.55102.55820.000
102.54102.54102.54102.55102.55825.000
102.54102.54102.54102.54102.54830.000
102.53102.53102.53102.53102.53835.000
102.52102.53102.53102.53102.53840.000
102.52102.52102.52102.52102.52845.000
102.51102.51102.51102.52102.52850.000
102.51102.51102.51102.51102.51855.000
102.50102.50102.50102.50102.50860.000
102.49102.50102.50102.50102.50865.000
102.49102.49102.49102.49102.49870.000
102.48102.48102.48102.49102.49875.000
102.48102.48102.48102.48102.48880.000
102.47102.47102.47102.47102.48885.000
102.46102.47102.47102.47102.47890.000
102.46102.46102.46102.46102.46895.000
102.45102.45102.46102.46102.46900.000
102.45102.45102.45102.45102.45905.000
102.44102.44102.44102.44102.45910.000
102.44102.44102.44102.44102.44915.000
102.43102.43102.43102.43102.43920.000
102.42102.42102.43102.43102.43925.000
102.42102.42102.42102.42102.42930.000
102.41102.41102.41102.42102.42935.000
102.41102.41102.41102.41102.41940.000
102.40102.40102.40102.40102.40945.000
102.39102.40102.40102.40102.40950.000
102.39102.39102.39102.39102.39955.000
102.38102.38102.39102.39102.39960.000
102.38102.38102.38102.38102.38965.000
102.37102.37102.37102.37102.38970.000
102.37102.37102.37102.37102.37975.000
102.36102.36102.36102.36102.36980.000
102.35102.35102.36102.36102.36985.000
102.35102.35102.35102.35102.35990.000
102.34102.34102.34102.35102.35995.000
102.34102.34102.34102.34102.341,000.000
102.33102.33102.33102.33102.341,005.000
102.32102.33102.33102.33102.331,010.000
102.32102.32102.32102.32102.321,015.000
Page 9 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
102.31102.31102.32102.32102.321,020.000
102.31102.31102.31102.31102.311,025.000
102.30102.30102.30102.31102.311,030.000
102.30102.30102.30102.30102.301,035.000
102.29102.29102.29102.29102.291,040.000
102.28102.29102.29102.29102.291,045.000
102.28102.28102.28102.28102.281,050.000
102.27102.27102.28102.28102.281,055.000
102.27102.27102.27102.27102.271,060.000
102.26102.26102.26102.26102.271,065.000
102.26102.26102.26102.26102.261,070.000
102.25102.25102.25102.25102.251,075.000
102.24102.25102.25102.25102.251,080.000
102.24102.24102.24102.24102.241,085.000
102.23102.23102.24102.24102.241,090.000
102.23102.23102.23102.23102.231,095.000
102.22102.22102.22102.22102.231,100.000
102.22102.22102.22102.22102.221,105.000
102.21102.21102.21102.21102.211,110.000
102.20102.21102.21102.21102.211,115.000
102.20102.20102.20102.20102.201,120.000
102.19102.19102.20102.20102.201,125.000
102.19102.19102.19102.19102.191,130.000
102.18102.18102.18102.18102.191,135.000
102.18102.18102.18102.18102.181,140.000
102.17102.17102.17102.17102.171,145.000
102.16102.17102.17102.17102.171,150.000
102.16102.16102.16102.16102.161,155.000
102.15102.15102.16102.16102.161,160.000
102.15102.15102.15102.15102.151,165.000
102.14102.14102.14102.15102.151,170.000
102.14102.14102.14102.14102.141,175.000
102.13102.13102.13102.13102.141,180.000
102.13102.13102.13102.13102.131,185.000
102.12102.12102.12102.12102.121,190.000
102.11102.11102.12102.12102.121,195.000
102.11102.11102.11102.11102.111,200.000
102.10102.10102.10102.11102.111,205.000
102.10102.10102.10102.10102.101,210.000
102.09102.09102.09102.09102.101,215.000
102.09102.09102.09102.09102.091,220.000
Page 10 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
102.08102.08102.08102.08102.081,225.000
102.07102.08102.08102.08102.081,230.000
102.07102.07102.07102.07102.071,235.000
102.06102.06102.07102.07102.071,240.000
102.06102.06102.06102.06102.061,245.000
102.05102.05102.05102.06102.061,250.000
102.05102.05102.05102.05102.051,255.000
102.04102.04102.04102.04102.051,260.000
102.04102.04102.04102.04102.041,265.000
102.03102.03102.03102.03102.031,270.000
102.02102.03102.03102.03102.031,275.000
102.02102.02102.02102.02102.021,280.000
102.01102.01102.02102.02102.021,285.000
102.01102.01102.01102.01102.011,290.000
102.00102.00102.00102.01102.011,295.000
102.00102.00102.00102.00102.001,300.000
101.99101.99101.99101.99102.001,305.000
101.99101.99101.99101.99101.991,310.000
101.98101.98101.98101.98101.981,315.000
101.97101.98101.98101.98101.981,320.000
101.97101.97101.97101.97101.971,325.000
101.96101.96101.97101.97101.971,330.000
101.96101.96101.96101.96101.961,335.000
101.95101.95101.96101.96101.961,340.000
101.95101.95101.95101.95101.951,345.000
101.94101.94101.94101.95101.951,350.000
101.94101.94101.94101.94101.941,355.000
101.93101.93101.93101.93101.941,360.000
101.93101.93101.93101.93101.931,365.000
101.92101.92101.92101.92101.921,370.000
101.91101.92101.92101.92101.921,375.000
101.91101.91101.91101.91101.911,380.000
101.90101.90101.91101.91101.911,385.000
101.90101.90101.90101.90101.901,390.000
101.89101.89101.89101.90101.901,395.000
101.89101.89101.89101.89101.891,400.000
101.88101.88101.88101.89101.891,405.000
101.88101.88101.88101.88101.881,410.000
101.87101.87101.87101.87101.881,415.000
101.87101.87101.87101.87101.871,420.000
101.86101.86101.86101.86101.861,425.000
Page 11 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
101.85101.86101.86101.86101.861,430.000
101.85101.85101.85101.85101.851,435.000
101.84101.85101.85101.85101.851,440.000
101.84101.84101.84101.84101.841,445.000
101.83101.83101.84101.84101.841,450.000
101.83101.83101.83101.83101.831,455.000
101.82101.82101.82101.83101.831,460.000
101.82101.82101.82101.82101.821,465.000
101.81101.81101.81101.81101.821,470.000
101.81101.81101.81101.81101.811,475.000
101.80101.80101.80101.80101.811,480.000
101.80101.80101.80101.80101.801,485.000
101.79101.79101.79101.79101.791,490.000
101.78101.79101.79101.79101.791,495.000
101.78101.78101.78101.78101.781,500.000
101.77101.78101.78101.78101.781,505.000
101.77101.77101.77101.77101.771,510.000
101.76101.76101.77101.77101.771,515.000
101.76101.76101.76101.76101.761,520.000
101.75101.75101.76101.76101.761,525.000
101.75101.75101.75101.75101.751,530.000
101.74101.74101.74101.75101.751,535.000
101.74101.74101.74101.74101.741,540.000
101.73101.73101.73101.73101.741,545.000
101.73101.73101.73101.73101.731,550.000
101.72101.72101.72101.72101.731,555.000
101.72101.72101.72101.72101.721,560.000
101.71101.71101.71101.71101.711,565.000
101.71101.71101.71101.71101.711,570.000
101.70101.70101.70101.70101.701,575.000
101.69101.70101.70101.70101.701,580.000
101.69101.69101.69101.69101.691,585.000
101.68101.69101.69101.69101.691,590.000
101.68101.68101.68101.68101.681,595.000
101.67101.67101.68101.68101.681,600.000
101.67101.67101.67101.67101.671,605.000
101.66101.66101.67101.67101.671,610.000
101.66101.66101.66101.66101.661,615.000
101.65101.65101.65101.66101.661,620.000
101.65101.65101.65101.65101.651,625.000
101.64101.64101.64101.65101.651,630.000
Page 12 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
101.64101.64101.64101.64101.641,635.000
101.63101.63101.63101.63101.641,640.000
101.63101.63101.63101.63101.631,645.000
101.62101.62101.62101.62101.631,650.000
101.62101.62101.62101.62101.621,655.000
101.61101.61101.61101.61101.621,660.000
101.61101.61101.61101.61101.611,665.000
101.60101.60101.60101.60101.601,670.000
101.60101.60101.60101.60101.601,675.000
101.59101.59101.59101.59101.591,680.000
101.58101.59101.59101.59101.591,685.000
101.58101.58101.58101.58101.581,690.000
101.57101.58101.58101.58101.581,695.000
101.57101.57101.57101.57101.571,700.000
101.56101.57101.57101.57101.571,705.000
101.56101.56101.56101.56101.561,710.000
101.55101.55101.56101.56101.561,715.000
101.55101.55101.55101.55101.551,720.000
101.54101.54101.55101.55101.551,725.000
101.54101.54101.54101.54101.541,730.000
101.53101.53101.54101.54101.541,735.000
101.53101.53101.53101.53101.531,740.000
101.52101.52101.53101.53101.531,745.000
101.52101.52101.52101.52101.521,750.000
101.51101.51101.51101.52101.521,755.000
101.51101.51101.51101.51101.511,760.000
101.50101.50101.50101.51101.511,765.000
101.50101.50101.50101.50101.501,770.000
101.49101.49101.49101.50101.501,775.000
101.49101.49101.49101.49101.491,780.000
101.48101.48101.48101.49101.491,785.000
101.48101.48101.48101.48101.481,790.000
101.47101.47101.47101.48101.481,795.000
101.47101.47101.47101.47101.471,800.000
101.46101.46101.46101.46101.471,805.000
101.46101.46101.46101.46101.461,810.000
101.45101.45101.45101.45101.461,815.000
101.45101.45101.45101.45101.451,820.000
101.44101.44101.44101.44101.451,825.000
101.44101.44101.44101.44101.441,830.000
101.43101.43101.43101.43101.441,835.000
Page 13 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
101.43101.43101.43101.43101.431,840.000
101.42101.42101.42101.42101.431,845.000
101.42101.42101.42101.42101.421,850.000
101.41101.41101.41101.41101.421,855.000
101.41101.41101.41101.41101.411,860.000
101.40101.40101.40101.40101.411,865.000
101.40101.40101.40101.40101.401,870.000
101.39101.39101.39101.39101.401,875.000
101.39101.39101.39101.39101.391,880.000
101.38101.38101.38101.38101.391,885.000
101.38101.38101.38101.38101.381,890.000
101.37101.37101.37101.37101.381,895.000
101.37101.37101.37101.37101.371,900.000
101.36101.36101.36101.36101.371,905.000
101.36101.36101.36101.36101.361,910.000
101.35101.35101.35101.35101.361,915.000
101.35101.35101.35101.35101.351,920.000
101.34101.34101.34101.34101.351,925.000
101.34101.34101.34101.34101.341,930.000
101.33101.33101.33101.33101.341,935.000
101.33101.33101.33101.33101.331,940.000
101.32101.32101.32101.32101.331,945.000
101.32101.32101.32101.32101.321,950.000
101.31101.31101.31101.31101.321,955.000
101.31101.31101.31101.31101.311,960.000
101.30101.30101.30101.30101.311,965.000
101.30101.30101.30101.30101.301,970.000
101.29101.29101.29101.30101.301,975.000
101.29101.29101.29101.29101.291,980.000
101.28101.28101.28101.29101.291,985.000
101.28101.28101.28101.28101.281,990.000
101.27101.27101.27101.28101.281,995.000
101.27101.27101.27101.27101.272,000.000
101.26101.26101.26101.27101.272,005.000
101.26101.26101.26101.26101.262,010.000
101.25101.25101.25101.26101.262,015.000
101.25101.25101.25101.25101.252,020.000
101.24101.24101.25101.25101.252,025.000
101.24101.24101.24101.24101.242,030.000
101.23101.23101.24101.24101.242,035.000
101.23101.23101.23101.23101.232,040.000
Page 14 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
101.22101.22101.23101.23101.232,045.000
101.22101.22101.22101.22101.222,050.000
101.21101.21101.22101.22101.222,055.000
101.21101.21101.21101.21101.212,060.000
101.20101.21101.21101.21101.212,065.000
101.20101.20101.20101.20101.202,070.000
101.19101.20101.20101.20101.202,075.000
101.19101.19101.19101.19101.192,080.000
101.19101.19101.19101.19101.192,085.000
101.18101.18101.18101.18101.182,090.000
101.18101.18101.18101.18101.182,095.000
101.17101.17101.17101.17101.172,100.000
101.17101.17101.17101.17101.172,105.000
101.16101.16101.16101.16101.162,110.000
101.16101.16101.16101.16101.162,115.000
101.15101.15101.15101.15101.162,120.000
101.15101.15101.15101.15101.152,125.000
101.14101.14101.14101.14101.152,130.000
101.14101.14101.14101.14101.142,135.000
101.13101.13101.13101.14101.142,140.000
101.13101.13101.13101.13101.132,145.000
101.12101.12101.12101.13101.132,150.000
101.12101.12101.12101.12101.122,155.000
101.11101.11101.12101.12101.122,160.000
101.11101.11101.11101.11101.112,165.000
101.10101.10101.11101.11101.112,170.000
101.10101.10101.10101.10101.102,175.000
101.09101.10101.10101.10101.102,180.000
101.09101.09101.09101.09101.092,185.000
101.08101.09101.09101.09101.092,190.000
101.08101.08101.08101.08101.082,195.000
101.08101.08101.08101.08101.082,200.000
101.07101.07101.07101.07101.072,205.000
101.07101.07101.07101.07101.072,210.000
101.06101.06101.06101.06101.062,215.000
101.06101.06101.06101.06101.062,220.000
101.05101.05101.05101.05101.062,225.000
101.05101.05101.05101.05101.052,230.000
101.04101.04101.04101.05101.052,235.000
101.04101.04101.04101.04101.042,240.000
101.03101.03101.03101.04101.042,245.000
Page 15 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
101.03101.03101.03101.03101.032,250.000
101.02101.02101.03101.03101.032,255.000
101.02101.02101.02101.02101.022,260.000
101.01101.02101.02101.02101.022,265.000
101.01101.01101.01101.01101.012,270.000
101.01101.01101.01101.01101.012,275.000
101.00101.00101.00101.00101.002,280.000
101.00101.00101.00101.00101.002,285.000
100.99100.99100.99100.99100.992,290.000
100.99100.99100.99100.99100.992,295.000
100.98100.98100.98100.98100.992,300.000
100.98100.98100.98100.98100.982,305.000
100.97100.97100.97100.98100.982,310.000
100.97100.97100.97100.97100.972,315.000
100.96100.96100.97100.97100.972,320.000
100.96100.96100.96100.96100.962,325.000
100.95100.96100.96100.96100.962,330.000
100.95100.95100.95100.95100.952,335.000
100.95100.95100.95100.95100.952,340.000
100.94100.94100.94100.94100.942,345.000
100.94100.94100.94100.94100.942,350.000
100.93100.93100.93100.93100.932,355.000
100.93100.93100.93100.93100.932,360.000
100.92100.92100.92100.92100.932,365.000
100.92100.92100.92100.92100.922,370.000
100.91100.91100.91100.92100.922,375.000
100.91100.91100.91100.91100.912,380.000
100.90100.90100.91100.91100.912,385.000
100.90100.90100.90100.90100.902,390.000
100.89100.90100.90100.90100.902,395.000
100.89100.89100.89100.89100.892,400.000
100.89100.89100.89100.89100.892,405.000
100.88100.88100.88100.88100.882,410.000
100.88100.88100.88100.88100.882,415.000
100.87100.87100.87100.87100.882,420.000
100.87100.87100.87100.87100.872,425.000
100.86100.86100.86100.87100.872,430.000
100.86100.86100.86100.86100.862,435.000
100.85100.86100.86100.86100.862,440.000
100.85100.85100.85100.85100.852,445.000
100.85100.85100.85100.85100.852,450.000
Page 16 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
100.84100.84100.84100.84100.842,455.000
100.84100.84100.84100.84100.842,460.000
100.83100.83100.83100.83100.842,465.000
100.83100.83100.83100.83100.832,470.000
100.82100.82100.82100.83100.832,475.000
100.82100.82100.82100.82100.822,480.000
100.81100.81100.82100.82100.822,485.000
100.81100.81100.81100.81100.812,490.000
100.80100.81100.81100.81100.812,495.000
100.80100.80100.80100.80100.802,500.000
100.80100.80100.80100.80100.802,505.000
100.79100.79100.79100.79100.802,510.000
100.79100.79100.79100.79100.792,515.000
100.78100.78100.78100.79100.792,520.000
100.78100.78100.78100.78100.782,525.000
100.77100.77100.78100.78100.782,530.000
100.77100.77100.77100.77100.772,535.000
100.76100.77100.77100.77100.772,540.000
100.76100.76100.76100.76100.762,545.000
100.76100.76100.76100.76100.762,550.000
100.75100.75100.75100.75100.762,555.000
100.75100.75100.75100.75100.752,560.000
100.74100.74100.74100.75100.752,565.000
100.74100.74100.74100.74100.742,570.000
100.73100.74100.74100.74100.742,575.000
100.73100.73100.73100.73100.732,580.000
100.73100.73100.73100.73100.732,585.000
100.72100.72100.72100.72100.722,590.000
100.72100.72100.72100.72100.722,595.000
100.71100.71100.71100.71100.722,600.000
100.71100.71100.71100.71100.712,605.000
100.70100.70100.71100.71100.712,610.000
100.70100.70100.70100.70100.702,615.000
100.69100.70100.70100.70100.702,620.000
100.69100.69100.69100.69100.692,625.000
100.69100.69100.69100.69100.692,630.000
100.68100.68100.68100.68100.692,635.000
100.68100.68100.68100.68100.682,640.000
100.67100.67100.68100.68100.682,645.000
100.67100.67100.67100.67100.672,650.000
100.66100.67100.67100.67100.672,655.000
Page 17 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
100.66100.66100.66100.66100.662,660.000
100.66100.66100.66100.66100.662,665.000
100.65100.65100.65100.65100.662,670.000
100.65100.65100.65100.65100.652,675.000
100.64100.64100.64100.65100.652,680.000
100.64100.64100.64100.64100.642,685.000
100.63100.64100.64100.64100.642,690.000
100.63100.63100.63100.63100.632,695.000
100.63100.63100.63100.63100.632,700.000
100.62100.62100.62100.62100.632,705.000
100.62100.62100.62100.62100.622,710.000
100.61100.61100.62100.62100.622,715.000
100.61100.61100.61100.61100.612,720.000
100.60100.61100.61100.61100.612,725.000
100.60100.60100.60100.60100.602,730.000
100.60100.60100.60100.60100.602,735.000
100.59100.59100.59100.59100.602,740.000
100.59100.59100.59100.59100.592,745.000
100.58100.58100.59100.59100.592,750.000
100.58100.58100.58100.58100.582,755.000
100.58100.58100.58100.58100.582,760.000
100.57100.57100.57100.57100.572,765.000
100.57100.57100.57100.57100.572,770.000
100.56100.56100.56100.57100.572,775.000
100.56100.56100.56100.56100.562,780.000
100.55100.56100.56100.56100.562,785.000
100.55100.55100.55100.55100.552,790.000
100.55100.55100.55100.55100.552,795.000
100.54100.54100.54100.54100.542,800.000
100.54100.54100.54100.54100.542,805.000
100.53100.53100.53100.54100.542,810.000
100.53100.53100.53100.53100.532,815.000
100.52100.53100.53100.53100.532,820.000
100.52100.52100.52100.52100.522,825.000
100.52100.52100.52100.52100.522,830.000
100.51100.51100.51100.51100.522,835.000
100.51100.51100.51100.51100.512,840.000
100.50100.51100.51100.51100.512,845.000
100.50100.50100.50100.50100.502,850.000
100.50100.50100.50100.50100.502,855.000
100.49100.49100.49100.49100.502,860.000
Page 18 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (OUT)
Return Event: 100 yearsSubsection: Time vs. Elevation
Time vs. Elevation (ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Elevation
(ft)
Time
(min)
100.49100.49100.49100.49100.492,865.000
100.48100.48100.49100.49100.492,870.000
100.48100.48100.48100.48100.482,875.000
100.48100.48100.48100.48100.482,880.000
100.47100.47100.47100.47100.472,885.000
100.47100.47100.47100.47100.472,890.000
100.46100.46100.46100.47100.472,895.000
100.46100.46100.46100.46100.462,900.000
100.45100.46100.46100.46100.462,905.000
100.45100.45100.45100.45100.452,910.000
100.45100.45100.45100.45100.452,915.000
100.44100.44100.44100.45100.452,920.000
100.44100.44100.44100.44100.442,925.000
100.43100.44100.44100.44100.442,930.000
100.43100.43100.43100.43100.432,935.000
100.43100.43100.43100.43100.432,940.000
100.42100.42100.42100.42100.432,945.000
100.42100.42100.42100.42100.422,950.000
100.41100.42100.42100.42100.422,955.000
100.41100.41100.41100.41100.412,960.000
100.41100.41100.41100.41100.412,965.000
100.40100.40100.40100.40100.412,970.000
100.40100.40100.40100.40100.402,975.000
100.39100.39100.40100.40100.402,980.000
100.39100.39100.39100.39100.392,985.000
100.39100.39100.39100.39100.392,990.000
100.38100.38100.38100.38100.392,995.000
(N/A)(N/A)(N/A)(N/A)100.383,000.000
Page 19 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.0030.0030.0030.0030.0030.000
0.0060.0050.0040.0040.0035.000
0.0120.0100.0090.0080.00710.000
0.0200.0180.0170.0150.01315.000
0.0280.0270.0250.0240.02220.000
0.0350.0340.0320.0310.02925.000
0.0420.0410.0390.0380.03630.000
0.0490.0470.0460.0450.04335.000
0.0560.0540.0530.0520.05040.000
0.0630.0620.0600.0590.05745.000
0.0710.0690.0680.0660.06550.000
0.0780.0770.0750.0740.07255.000
0.0860.0840.0830.0810.08060.000
0.0940.0920.0910.0890.08765.000
0.1020.1000.0990.0970.09570.000
0.1100.1080.1070.1050.10375.000
0.1180.1160.1150.1130.11280.000
0.1260.1250.1230.1210.12085.000
0.1350.1330.1310.1300.12890.000
0.1430.1420.1400.1380.13695.000
0.1520.1510.1490.1470.145100.000
0.1610.1590.1580.1560.154105.000
0.1710.1690.1670.1650.163110.000
0.1810.1790.1770.1750.173115.000
0.1910.1890.1870.1850.183120.000
0.2010.1990.1970.1950.193125.000
0.2110.2090.2070.2050.203130.000
0.2220.2200.2180.2150.213135.000
0.2330.2310.2290.2260.224140.000
0.2450.2420.2400.2380.235145.000
0.2570.2540.2520.2500.247150.000
0.2690.2670.2640.2620.259155.000
0.2820.2800.2770.2740.272160.000
0.2960.2930.2900.2870.285165.000
0.3090.3060.3040.3010.298170.000
0.3230.3210.3180.3150.312175.000
0.3390.3360.3330.3300.326180.000
0.3550.3520.3490.3450.342185.000
0.3720.3690.3650.3620.359190.000
0.3900.3870.3830.3790.376195.000
Page 20 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.4100.4060.4020.3980.394200.000
0.4310.4270.4230.4190.414205.000
0.4550.4500.4450.4410.436210.000
0.4820.4760.4710.4650.460215.000
0.5100.5040.4980.4930.487220.000
0.5450.5370.5300.5230.516225.000
0.5900.5790.5700.5610.553230.000
0.6550.6400.6260.6130.601235.000
0.7620.7340.7100.6880.671240.000
0.9450.9050.8640.8270.793245.000
1.0801.0621.0391.0120.981250.000
1.1221.1161.1091.1021.093255.000
1.1481.1441.1391.1331.128260.000
1.1701.1661.1621.1571.153265.000
1.1871.1841.1811.1771.173270.000
1.2011.1991.1961.1941.191275.000
1.2101.2091.2071.2051.203280.000
1.2161.2151.2141.2131.212285.000
1.2201.2201.2191.2181.217290.000
1.2221.2221.2221.2211.221295.000
1.2231.2231.2231.2231.223300.000
1.2241.2241.2241.2231.223305.000
1.2231.2231.2231.2231.223310.000
1.2231.2231.2231.2231.223315.000
1.2221.2221.2221.2221.223320.000
1.2211.2211.2211.2211.222325.000
1.2201.2201.2201.2201.221330.000
1.2181.2191.2191.2191.219335.000
1.2171.2181.2181.2181.218340.000
1.2171.2171.2171.2171.217345.000
1.2151.2161.2161.2161.216350.000
1.2151.2151.2151.2151.215355.000
1.2121.2131.2141.2141.214360.000
1.2071.2081.2091.2101.212365.000
1.2011.2021.2031.2041.205370.000
1.1971.1971.1981.1991.200375.000
1.1931.1941.1941.1951.196380.000
1.1901.1911.1911.1921.193385.000
1.1881.1881.1891.1891.190390.000
1.1851.1861.1861.1871.187395.000
1.1831.1841.1841.1841.185400.000
Page 21 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
1.1811.1821.1821.1821.183405.000
1.1791.1801.1801.1811.181410.000
1.1781.1781.1781.1791.179415.000
1.1761.1761.1771.1771.177420.000
1.1741.1741.1751.1751.175425.000
1.1721.1721.1731.1731.174430.000
1.1701.1711.1711.1711.172435.000
1.1681.1691.1691.1701.170440.000
1.1671.1671.1671.1681.168445.000
1.1651.1651.1651.1661.166450.000
1.1631.1631.1641.1641.164455.000
1.1611.1611.1621.1621.163460.000
1.1591.1601.1601.1601.161465.000
1.1571.1581.1581.1591.159470.000
1.1561.1561.1561.1571.157475.000
1.1541.1541.1541.1551.155480.000
1.1521.1521.1531.1531.153485.000
1.1501.1501.1511.1511.152490.000
1.1481.1491.1491.1491.150495.000
1.1461.1471.1471.1481.148500.000
1.1451.1451.1451.1461.146505.000
1.1431.1431.1441.1441.144510.000
1.1411.1411.1421.1421.142515.000
1.1391.1401.1401.1401.141520.000
1.1371.1381.1381.1381.139525.000
1.1361.1361.1361.1371.137530.000
1.1341.1341.1341.1351.135535.000
1.1321.1321.1331.1331.133540.000
1.1301.1301.1311.1311.132545.000
1.1281.1291.1291.1291.130550.000
1.1261.1271.1271.1281.128555.000
1.1251.1251.1251.1261.126560.000
1.1231.1231.1241.1241.124565.000
1.1211.1211.1221.1221.122570.000
1.1191.1201.1201.1201.121575.000
1.1171.1181.1181.1191.119580.000
1.1161.1161.1161.1171.117585.000
1.1141.1141.1151.1151.115590.000
1.1121.1121.1131.1131.113595.000
1.1101.1111.1111.1111.112600.000
1.1081.1091.1091.1101.110605.000
Page 22 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
1.1071.1071.1071.1081.108610.000
1.1051.1051.1061.1061.106615.000
1.1031.1031.1041.1041.104620.000
1.1011.1021.1021.1021.103625.000
1.0991.1001.1001.1011.101630.000
1.0981.0981.0981.0991.099635.000
1.0961.0961.0971.0971.097640.000
1.0941.0941.0951.0951.096645.000
1.0921.0931.0931.0931.094650.000
1.0911.0911.0911.0921.092655.000
1.0891.0891.0891.0901.090660.000
1.0871.0871.0881.0881.088665.000
1.0851.0861.0861.0861.087670.000
1.0831.0841.0841.0841.085675.000
1.0821.0821.0821.0831.083680.000
1.0801.0801.0811.0811.081685.000
1.0781.0781.0791.0791.079690.000
1.0761.0771.0771.0771.078695.000
1.0751.0751.0751.0761.076700.000
1.0731.0731.0731.0741.074705.000
1.0711.0711.0721.0721.072710.000
1.0691.0701.0701.0701.071715.000
1.0671.0681.0681.0691.069720.000
1.0661.0661.0661.0671.067725.000
1.0641.0641.0651.0651.065730.000
1.0621.0621.0631.0631.064735.000
1.0601.0611.0611.0611.062740.000
1.0591.0591.0591.0601.060745.000
1.0571.0571.0581.0581.058750.000
1.0551.0551.0561.0561.057755.000
1.0531.0541.0541.0541.055760.000
1.0521.0521.0521.0531.053765.000
1.0501.0501.0511.0511.051770.000
1.0481.0481.0491.0491.049775.000
1.0461.0471.0471.0471.048780.000
1.0451.0451.0451.0461.046785.000
1.0431.0431.0441.0441.044790.000
1.0411.0411.0421.0421.042795.000
1.0391.0401.0401.0401.041800.000
1.0381.0381.0381.0391.039805.000
1.0361.0361.0371.0371.037810.000
Page 23 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
1.0341.0341.0351.0351.036815.000
1.0321.0331.0331.0331.034820.000
1.0311.0311.0311.0321.032825.000
1.0291.0291.0301.0301.030830.000
1.0271.0281.0281.0281.029835.000
1.0251.0261.0261.0261.027840.000
1.0241.0241.0241.0251.025845.000
1.0221.0221.0231.0231.023850.000
1.0201.0211.0211.0211.022855.000
1.0181.0191.0191.0201.020860.000
1.0171.0171.0171.0181.018865.000
1.0151.0151.0161.0161.016870.000
1.0131.0141.0141.0141.015875.000
1.0121.0121.0121.0131.013880.000
1.0101.0101.0111.0111.011885.000
1.0081.0081.0091.0091.010890.000
1.0061.0071.0071.0071.008895.000
1.0051.0051.0051.0061.006900.000
1.0031.0031.0041.0041.004905.000
1.0011.0021.0021.0021.003910.000
1.0001.0001.0001.0011.001915.000
0.9980.9980.9990.9990.999920.000
0.9960.9960.9970.9970.997925.000
0.9940.9950.9950.9950.996930.000
0.9930.9930.9930.9940.994935.000
0.9910.9910.9920.9920.992940.000
0.9890.9900.9900.9900.991945.000
0.9880.9880.9880.9890.989950.000
0.9860.9860.9870.9870.987955.000
0.9840.9850.9850.9850.986960.000
0.9820.9830.9830.9830.984965.000
0.9810.9810.9810.9820.982970.000
0.9790.9790.9800.9800.980975.000
0.9770.9780.9780.9780.979980.000
0.9760.9760.9760.9770.977985.000
0.9740.9740.9750.9750.975990.000
0.9720.9730.9730.9730.974995.000
0.9710.9710.9710.9720.9721,000.000
0.9690.9690.9700.9700.9701,005.000
0.9670.9680.9680.9680.9691,010.000
0.9650.9660.9660.9670.9671,015.000
Page 24 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.9640.9640.9640.9650.9651,020.000
0.9620.9620.9630.9630.9631,025.000
0.9600.9610.9610.9610.9621,030.000
0.9590.9590.9590.9600.9601,035.000
0.9570.9570.9580.9580.9581,040.000
0.9550.9560.9560.9560.9571,045.000
0.9540.9540.9540.9550.9551,050.000
0.9520.9520.9530.9530.9531,055.000
0.9500.9510.9510.9510.9521,060.000
0.9490.9490.9490.9500.9501,065.000
0.9470.9470.9480.9480.9481,070.000
0.9450.9460.9460.9460.9471,075.000
0.9440.9440.9440.9450.9451,080.000
0.9420.9420.9430.9430.9431,085.000
0.9400.9410.9410.9410.9421,090.000
0.9390.9390.9390.9400.9401,095.000
0.9370.9370.9380.9380.9381,100.000
0.9350.9360.9360.9360.9371,105.000
0.9340.9340.9340.9350.9351,110.000
0.9320.9320.9330.9330.9331,115.000
0.9300.9310.9310.9310.9321,120.000
0.9290.9290.9290.9300.9301,125.000
0.9270.9270.9280.9280.9281,130.000
0.9250.9260.9260.9260.9271,135.000
0.9240.9240.9240.9250.9251,140.000
0.9220.9220.9230.9230.9231,145.000
0.9200.9210.9210.9210.9221,150.000
0.9190.9190.9190.9200.9201,155.000
0.9170.9170.9180.9180.9181,160.000
0.9150.9160.9160.9160.9171,165.000
0.9140.9140.9140.9150.9151,170.000
0.9120.9120.9130.9130.9131,175.000
0.9100.9110.9110.9110.9121,180.000
0.9090.9090.9090.9100.9101,185.000
0.9070.9080.9080.9080.9081,190.000
0.9060.9060.9060.9070.9071,195.000
0.9040.9040.9050.9050.9051,200.000
0.9020.9030.9030.9030.9041,205.000
0.9010.9010.9010.9020.9021,210.000
0.8990.8990.9000.9000.9001,215.000
0.8970.8980.8980.8980.8991,220.000
Page 25 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.8960.8960.8960.8970.8971,225.000
0.8940.8940.8950.8950.8951,230.000
0.8920.8930.8930.8930.8941,235.000
0.8910.8910.8910.8920.8921,240.000
0.8890.8890.8900.8900.8901,245.000
0.8880.8880.8880.8890.8891,250.000
0.8860.8860.8870.8870.8871,255.000
0.8840.8850.8850.8850.8861,260.000
0.8830.8830.8830.8840.8841,265.000
0.8810.8810.8820.8820.8821,270.000
0.8790.8800.8800.8800.8811,275.000
0.8780.8780.8780.8790.8791,280.000
0.8760.8760.8770.8770.8771,285.000
0.8750.8750.8750.8760.8761,290.000
0.8730.8730.8740.8740.8741,295.000
0.8710.8720.8720.8720.8731,300.000
0.8700.8700.8700.8710.8711,305.000
0.8680.8680.8690.8690.8691,310.000
0.8660.8670.8670.8670.8681,315.000
0.8650.8650.8660.8660.8661,320.000
0.8630.8640.8640.8640.8651,325.000
0.8620.8620.8620.8630.8631,330.000
0.8600.8600.8610.8610.8611,335.000
0.8580.8590.8590.8590.8601,340.000
0.8570.8570.8570.8580.8581,345.000
0.8550.8560.8560.8560.8571,350.000
0.8540.8540.8540.8550.8551,355.000
0.8520.8520.8530.8530.8531,360.000
0.8500.8510.8510.8510.8521,365.000
0.8490.8490.8490.8500.8501,370.000
0.8470.8480.8480.8480.8491,375.000
0.8460.8460.8460.8470.8471,380.000
0.8440.8440.8450.8450.8451,385.000
0.8420.8430.8430.8430.8441,390.000
0.8410.8410.8420.8420.8421,395.000
0.8390.8400.8400.8400.8411,400.000
0.8380.8380.8380.8390.8391,405.000
0.8360.8360.8370.8370.8371,410.000
0.8350.8350.8350.8350.8361,415.000
0.8330.8330.8340.8340.8341,420.000
0.8310.8320.8320.8320.8331,425.000
Page 26 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.8300.8300.8300.8310.8311,430.000
0.8280.8290.8290.8290.8291,435.000
0.8270.8270.8270.8280.8281,440.000
0.8250.8250.8260.8260.8261,445.000
0.8230.8240.8240.8240.8251,450.000
0.8220.8220.8230.8230.8231,455.000
0.8200.8210.8210.8210.8221,460.000
0.8190.8190.8190.8200.8201,465.000
0.8170.8170.8180.8180.8181,470.000
0.8160.8160.8160.8170.8171,475.000
0.8140.8140.8150.8150.8151,480.000
0.8120.8130.8130.8130.8141,485.000
0.8110.8110.8120.8120.8121,490.000
0.8090.8100.8100.8100.8111,495.000
0.8080.8080.8080.8090.8091,500.000
0.8060.8070.8070.8070.8071,505.000
0.8050.8050.8050.8060.8061,510.000
0.8030.8030.8040.8040.8041,515.000
0.8020.8020.8020.8020.8031,520.000
0.8000.8000.8010.8010.8011,525.000
0.7980.7990.7990.7990.8001,530.000
0.7970.7970.7970.7980.7981,535.000
0.7950.7960.7960.7960.7971,540.000
0.7940.7940.7940.7950.7951,545.000
0.7920.7930.7930.7930.7931,550.000
0.7910.7910.7910.7920.7921,555.000
0.7890.7890.7900.7900.7901,560.000
0.7880.7880.7880.7890.7891,565.000
0.7860.7860.7870.7870.7871,570.000
0.7850.7850.7850.7850.7861,575.000
0.7830.7830.7840.7840.7841,580.000
0.7810.7820.7820.7820.7831,585.000
0.7800.7800.7800.7810.7811,590.000
0.7780.7790.7790.7790.7801,595.000
0.7770.7770.7770.7780.7781,600.000
0.7750.7760.7760.7760.7761,605.000
0.7740.7740.7740.7750.7751,610.000
0.7720.7720.7730.7730.7731,615.000
0.7710.7710.7710.7720.7721,620.000
0.7690.7690.7700.7700.7701,625.000
0.7680.7680.7680.7690.7691,630.000
Page 27 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.7660.7660.7670.7670.7671,635.000
0.7650.7650.7650.7650.7661,640.000
0.7630.7630.7640.7640.7641,645.000
0.7620.7620.7620.7620.7631,650.000
0.7600.7600.7610.7610.7611,655.000
0.7580.7590.7590.7590.7601,660.000
0.7570.7570.7580.7580.7581,665.000
0.7550.7560.7560.7560.7571,670.000
0.7540.7540.7550.7550.7551,675.000
0.7520.7530.7530.7530.7541,680.000
0.7510.7510.7510.7520.7521,685.000
0.7490.7500.7500.7500.7511,690.000
0.7480.7480.7480.7490.7491,695.000
0.7460.7470.7470.7470.7481,700.000
0.7450.7450.7450.7460.7461,705.000
0.7430.7440.7440.7440.7451,710.000
0.7420.7420.7420.7430.7431,715.000
0.7400.7410.7410.7410.7421,720.000
0.7390.7390.7390.7400.7401,725.000
0.7370.7380.7380.7380.7381,730.000
0.7360.7360.7360.7370.7371,735.000
0.7340.7350.7350.7350.7361,740.000
0.7330.7330.7330.7340.7341,745.000
0.7310.7320.7320.7320.7331,750.000
0.7300.7300.7300.7310.7311,755.000
0.7280.7290.7290.7290.7301,760.000
0.7270.7270.7270.7280.7281,765.000
0.7250.7260.7260.7260.7271,770.000
0.7240.7240.7240.7250.7251,775.000
0.7220.7230.7230.7230.7241,780.000
0.7210.7210.7210.7220.7221,785.000
0.7190.7200.7200.7200.7211,790.000
0.7180.7180.7180.7190.7191,795.000
0.7160.7170.7170.7170.7181,800.000
0.7150.7150.7160.7160.7161,805.000
0.7130.7140.7140.7140.7151,810.000
0.7120.7120.7130.7130.7131,815.000
0.7100.7110.7110.7110.7121,820.000
0.7090.7090.7100.7100.7101,825.000
0.7080.7080.7080.7080.7091,830.000
0.7060.7060.7070.7070.7071,835.000
Page 28 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.7050.7050.7050.7050.7061,840.000
0.7030.7030.7040.7040.7041,845.000
0.7020.7020.7020.7030.7031,850.000
0.7000.7000.7010.7010.7011,855.000
0.6990.6990.6990.7000.7001,860.000
0.6970.6980.6980.6980.6981,865.000
0.6960.6960.6960.6970.6971,870.000
0.6940.6950.6950.6950.6951,875.000
0.6930.6930.6930.6940.6941,880.000
0.6910.6920.6920.6920.6931,885.000
0.6900.6900.6900.6910.6911,890.000
0.6880.6890.6890.6890.6901,895.000
0.6870.6870.6880.6880.6881,900.000
0.6860.6860.6860.6860.6871,905.000
0.6840.6840.6850.6850.6851,910.000
0.6830.6830.6830.6830.6841,915.000
0.6810.6810.6820.6820.6821,920.000
0.6800.6800.6800.6810.6811,925.000
0.6780.6790.6790.6790.6791,930.000
0.6770.6770.6770.6780.6781,935.000
0.6750.6760.6760.6760.6771,940.000
0.6740.6740.6740.6750.6751,945.000
0.6720.6730.6730.6730.6741,950.000
0.6710.6710.6720.6720.6721,955.000
0.6700.6700.6700.6700.6711,960.000
0.6680.6680.6690.6690.6691,965.000
0.6670.6670.6670.6680.6681,970.000
0.6650.6660.6660.6660.6661,975.000
0.6640.6640.6640.6650.6651,980.000
0.6620.6630.6630.6630.6641,985.000
0.6610.6610.6620.6620.6621,990.000
0.6600.6600.6600.6600.6611,995.000
0.6580.6580.6590.6590.6592,000.000
0.6570.6570.6570.6580.6582,005.000
0.6550.6560.6560.6560.6562,010.000
0.6540.6540.6540.6550.6552,015.000
0.6520.6530.6530.6530.6542,020.000
0.6510.6510.6520.6520.6522,025.000
0.6500.6500.6500.6500.6512,030.000
0.6480.6480.6490.6490.6492,035.000
0.6470.6470.6470.6480.6482,040.000
Page 29 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.6450.6460.6460.6460.6462,045.000
0.6440.6440.6440.6450.6452,050.000
0.6420.6430.6430.6430.6442,055.000
0.6410.6410.6420.6420.6422,060.000
0.6400.6400.6400.6400.6412,065.000
0.6380.6380.6390.6390.6392,070.000
0.6370.6370.6370.6380.6382,075.000
0.6350.6360.6360.6360.6372,080.000
0.6340.6340.6350.6350.6352,085.000
0.6330.6330.6330.6330.6342,090.000
0.6310.6310.6320.6320.6322,095.000
0.6300.6300.6300.6310.6312,100.000
0.6280.6290.6290.6290.6292,105.000
0.6270.6270.6280.6280.6282,110.000
0.6260.6260.6260.6260.6272,115.000
0.6240.6240.6250.6250.6252,120.000
0.6230.6230.6230.6240.6242,125.000
0.6210.6220.6220.6220.6222,130.000
0.6200.6200.6210.6210.6212,135.000
0.6190.6190.6190.6190.6202,140.000
0.6170.6170.6180.6180.6182,145.000
0.6160.6160.6160.6170.6172,150.000
0.6140.6150.6150.6150.6152,155.000
0.6130.6130.6140.6140.6142,160.000
0.6120.6120.6120.6120.6132,165.000
0.6100.6100.6110.6110.6112,170.000
0.6090.6090.6090.6100.6102,175.000
0.6070.6080.6080.6080.6092,180.000
0.6060.6060.6070.6070.6072,185.000
0.6050.6050.6050.6050.6062,190.000
0.6030.6040.6040.6040.6042,195.000
0.6020.6020.6020.6030.6032,200.000
0.6010.6010.6010.6010.6022,205.000
0.5990.5990.6000.6000.6002,210.000
0.5980.5980.5980.5990.5992,215.000
0.5960.5970.5970.5970.5972,220.000
0.5950.5950.5960.5960.5962,225.000
0.5940.5940.5940.5940.5952,230.000
0.5920.5930.5930.5930.5932,235.000
0.5910.5910.5910.5920.5922,240.000
0.5900.5900.5900.5900.5912,245.000
Page 30 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.5880.5880.5890.5890.5892,250.000
0.5870.5870.5870.5880.5882,255.000
0.5850.5860.5860.5860.5872,260.000
0.5840.5840.5850.5850.5852,265.000
0.5830.5830.5830.5840.5842,270.000
0.5810.5820.5820.5820.5822,275.000
0.5800.5800.5810.5810.5812,280.000
0.5790.5790.5790.5790.5802,285.000
0.5770.5780.5780.5780.5782,290.000
0.5760.5760.5760.5770.5772,295.000
0.5750.5750.5750.5750.5762,300.000
0.5730.5740.5740.5740.5742,305.000
0.5720.5720.5720.5730.5732,310.000
0.5710.5710.5710.5710.5722,315.000
0.5690.5690.5700.5700.5702,320.000
0.5680.5680.5680.5690.5692,325.000
0.5660.5670.5670.5670.5682,330.000
0.5650.5650.5660.5660.5662,335.000
0.5640.5640.5640.5650.5652,340.000
0.5620.5630.5630.5630.5642,345.000
0.5610.5610.5620.5620.5622,350.000
0.5600.5600.5600.5610.5612,355.000
0.5580.5590.5590.5590.5602,360.000
0.5570.5570.5580.5580.5582,365.000
0.5560.5560.5560.5570.5572,370.000
0.5540.5550.5550.5550.5562,375.000
0.5530.5530.5540.5540.5542,380.000
0.5520.5520.5520.5530.5532,385.000
0.5500.5510.5510.5510.5522,390.000
0.5490.5490.5500.5500.5502,395.000
0.5480.5480.5480.5490.5492,400.000
0.5460.5470.5470.5470.5482,405.000
0.5450.5450.5460.5460.5462,410.000
0.5440.5440.5440.5450.5452,415.000
0.5420.5430.5430.5430.5442,420.000
0.5410.5410.5420.5420.5422,425.000
0.5400.5400.5400.5410.5412,430.000
0.5390.5390.5390.5390.5402,435.000
0.5370.5370.5380.5380.5382,440.000
0.5360.5360.5360.5370.5372,445.000
0.5350.5350.5350.5350.5362,450.000
Page 31 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.5330.5340.5340.5340.5342,455.000
0.5320.5320.5320.5330.5332,460.000
0.5310.5310.5310.5310.5322,465.000
0.5290.5300.5300.5300.5302,470.000
0.5280.5280.5290.5290.5292,475.000
0.5270.5270.5270.5280.5282,480.000
0.5250.5260.5260.5260.5262,485.000
0.5240.5240.5250.5250.5252,490.000
0.5230.5230.5230.5240.5242,495.000
0.5220.5220.5220.5220.5232,500.000
0.5200.5200.5210.5210.5212,505.000
0.5190.5190.5190.5200.5202,510.000
0.5180.5180.5180.5180.5192,515.000
0.5160.5170.5170.5170.5172,520.000
0.5150.5150.5160.5160.5162,525.000
0.5140.5140.5140.5150.5152,530.000
0.5120.5130.5130.5130.5132,535.000
0.5110.5110.5120.5120.5122,540.000
0.5100.5100.5100.5110.5112,545.000
0.5090.5090.5090.5090.5102,550.000
0.5070.5080.5080.5080.5082,555.000
0.5060.5060.5070.5070.5072,560.000
0.5050.5050.5050.5050.5062,565.000
0.5030.5040.5040.5040.5042,570.000
0.5020.5020.5030.5030.5032,575.000
0.5010.5010.5010.5020.5022,580.000
0.5000.5000.5000.5000.5012,585.000
0.4980.4990.4990.4990.4992,590.000
0.4970.4970.4980.4980.4982,595.000
0.4960.4960.4960.4970.4972,600.000
0.4940.4950.4950.4950.4962,605.000
0.4930.4930.4940.4940.4942,610.000
0.4920.4920.4920.4930.4932,615.000
0.4910.4910.4910.4910.4922,620.000
0.4890.4900.4900.4900.4902,625.000
0.4880.4880.4890.4890.4892,630.000
0.4870.4870.4870.4880.4882,635.000
0.4860.4860.4860.4860.4872,640.000
0.4840.4850.4850.4850.4852,645.000
0.4830.4830.4840.4840.4842,650.000
0.4820.4820.4820.4830.4832,655.000
Page 32 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.4810.4810.4810.4810.4822,660.000
0.4790.4800.4800.4800.4802,665.000
0.4780.4780.4790.4790.4792,670.000
0.4770.4770.4770.4780.4782,675.000
0.4760.4760.4760.4760.4772,680.000
0.4740.4750.4750.4750.4752,685.000
0.4730.4730.4740.4740.4742,690.000
0.4720.4720.4720.4730.4732,695.000
0.4710.4710.4710.4710.4722,700.000
0.4690.4700.4700.4700.4702,705.000
0.4680.4680.4690.4690.4692,710.000
0.4670.4670.4670.4680.4682,715.000
0.4660.4660.4660.4660.4672,720.000
0.4640.4650.4650.4650.4652,725.000
0.4630.4630.4640.4640.4642,730.000
0.4620.4620.4620.4630.4632,735.000
0.4610.4610.4610.4610.4622,740.000
0.4590.4600.4600.4600.4602,745.000
0.4580.4580.4590.4590.4592,750.000
0.4570.4570.4570.4580.4582,755.000
0.4560.4560.4560.4560.4572,760.000
0.4540.4550.4550.4550.4552,765.000
0.4530.4530.4540.4540.4542,770.000
0.4520.4520.4520.4530.4532,775.000
0.4510.4510.4510.4510.4522,780.000
0.4500.4500.4500.4500.4512,785.000
0.4480.4490.4490.4490.4492,790.000
0.4470.4470.4480.4480.4482,795.000
0.4460.4460.4460.4470.4472,800.000
0.4450.4450.4450.4450.4462,805.000
0.4430.4440.4440.4440.4442,810.000
0.4420.4420.4430.4430.4432,815.000
0.4410.4410.4410.4420.4422,820.000
0.4400.4400.4400.4400.4412,825.000
0.4390.4390.4390.4390.4402,830.000
0.4370.4380.4380.4380.4382,835.000
0.4360.4360.4370.4370.4372,840.000
0.4350.4350.4350.4360.4362,845.000
0.4340.4340.4340.4340.4352,850.000
0.4320.4330.4330.4330.4332,855.000
0.4310.4320.4320.4320.4322,860.000
Page 33 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Time vs. Volume
Time vs. Volume (ac-ft)
Output Time increment = 1.000 min
Time on left represents time for first value in each row.
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Volume
(ac-ft)
Time
(min)
0.4300.4300.4310.4310.4312,865.000
0.4290.4290.4290.4300.4302,870.000
0.4280.4280.4280.4280.4292,875.000
0.4260.4270.4270.4270.4272,880.000
0.4250.4260.4260.4260.4262,885.000
0.4240.4240.4250.4250.4252,890.000
0.4230.4230.4230.4240.4242,895.000
0.4220.4220.4220.4220.4232,900.000
0.4200.4210.4210.4210.4212,905.000
0.4190.4200.4200.4200.4202,910.000
0.4180.4180.4190.4190.4192,915.000
0.4170.4170.4170.4180.4182,920.000
0.4160.4160.4160.4160.4172,925.000
0.4150.4150.4150.4150.4152,930.000
0.4130.4140.4140.4140.4142,935.000
0.4120.4120.4130.4130.4132,940.000
0.4110.4110.4110.4120.4122,945.000
0.4100.4100.4100.4100.4112,950.000
0.4090.4090.4090.4090.4102,955.000
0.4070.4080.4080.4080.4082,960.000
0.4060.4060.4070.4070.4072,965.000
0.4050.4050.4060.4060.4062,970.000
0.4040.4040.4040.4050.4052,975.000
0.4030.4030.4030.4030.4042,980.000
0.4020.4020.4020.4020.4022,985.000
0.4000.4010.4010.4010.4012,990.000
0.3990.3990.4000.4000.4002,995.000
(N/A)(N/A)(N/A)(N/A)0.3993,000.000
Page 34 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Elevation-Area Volume Curve
Volume (Total)
(ac-ft)
Volume
(ac-ft)
A1+A2+sqr
(A1*A2)
(ft²)
Area
(ft²)
Planimeter
(ft²)
Elevation
(ft)
0.0000.0000.000160.0000.098.50
0.0020.002480.000160.0000.098.96
0.0130.01114,323.50112,736.0000.099.06
1.4751.46238,208.00012,736.0000.0104.06
Page 35 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Volume Equations
Pond Volume Equations
* Incremental volume computed by the Conic Method for Reservoir Volumes.
Volume = (1/3) * (EL2 - El1) * (Area1 + Area2 + sqr(Area1 * Area2))
Lower and upper elevations of the incrementwhere: EL1, EL2
Areas computed for EL1, EL2, respectivelyArea1, Area2
Incremental volume between EL1 and EL2Volume
Page 36 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: Outlet#1
Return Event: 100 yearsSubsection: Outlet Input Data
Requested Pond Water Surface Elevations
ft98.50Minimum (Headwater)
ft0.10Increment (Headwater)
ft104.06Maximum (Headwater)
Outlet Connectivity
E2
(ft)
E1
(ft)
OutfallDirectionOutlet IDStructure Type
104.0698.50TWForwardOrifice -
MWS
Orifice-Circular
104.0698.50Weir - 1ForwardCulvert - 1Culvert-Circular
104.06103.06TWForwardWeir - 1Rectangular Weir
(N/A)(N/A)TailwaterTailwater Settings
Page 37 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: Outlet#1
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Orifice - MWS
Structure Type: Orifice-Circular
1Number of Openings
ft98.50Elevation
in2.2Orifice Diameter
0.600Orifice Coefficient
Page 38 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: Outlet#1
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Culvert - 1
Structure Type: Culvert-Circular
1Number of Barrels
in24.0Diameter
ft15.00Length
ft15.01Length (Computed Barrel)
ft/ft0.033Slope (Computed)
Outlet Control Data
0.013Manning's n
0.500Ke
0.012Kb
0.500Kr
ft0.00Convergence Tolerance
Inlet Control Data
Form 1Equation Form
0.0098K
2.0000M
0.0398C
0.6700Y
0.000T1 ratio (HW/D)
1.290T2 ratio (HW/D)
-0.500Slope Correction Factor
Use unsubmerged inlet control 0 equation below T1
elevation.
Use submerged inlet control 0 equation above T2
elevation
In transition zone between unsubmerged and submerged
inlet control,
interpolate between flows at T1 & T2...
ft98.50T1 Elevation ft³/s15.55T1 Flow
ft101.08T2 Elevation ft³/s17.77T2 Flow
Page 39 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: Outlet#1
Return Event: 100 yearsSubsection: Outlet Input Data
Structure ID: Weir - 1
Structure Type: Rectangular Weir
1Number of Openings
ft103.06Elevation
ft8.00Weir Length
(ft^0.5)/s3.00Weir Coefficient
Structure ID: TW
Structure Type: TW Setup, DS Channel
Free OutfallTailwater Type
Convergence Tolerances
30Maximum Iterations
ft0.01Tailwater Tolerance
(Minimum)
ft0.50Tailwater Tolerance
(Maximum)
ft0.01Headwater Tolerance
(Minimum)
ft0.50Headwater Tolerance
(Maximum)
ft³/s0.001Flow Tolerance (Minimum)
ft³/s10.000Flow Tolerance (Maximum)
Page 40 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
6/17/2022
PondPack CONNECT Edition
[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Elevation-Volume-Flow Table (Pond)
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft99.00Elevation (Water Surface,
Initial)
ac-ft0.003Volume (Initial)
ft³/s0.08Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.08Flow (Initial, Total)
min1.000Time Increment
2S/t + O
(ft³/s)
Flow (Total)
(ft³/s)
Infiltration
(ft³/s)
Area
(ft²)
Storage
(ac-ft)
Outflow
(ft³/s)
Elevation
(ft)
0.000.000.00160.0000.0000.0098.50
0.550.010.00160.0000.0000.0198.60
1.110.040.00160.0000.0010.0498.70
1.660.060.00160.0000.0010.0698.80
2.200.070.00160.0000.0010.0798.90
4.140.080.002,780.5610.0030.0899.00
35.440.090.0012,736.0000.0240.0999.10
77.900.100.0012,736.0000.0540.1099.20
120.360.110.0012,736.0000.0830.1199.30
162.820.110.0012,736.0000.1120.1199.40
205.280.120.0012,736.0000.1410.1299.50
247.740.130.0012,736.0000.1710.1399.60
290.200.130.0012,736.0000.2000.1399.70
332.660.140.0012,736.0000.2290.1499.80
375.120.150.0012,736.0000.2580.1599.90
417.580.150.0012,736.0000.2870.15100.00
460.040.160.0012,736.0000.3170.16100.10
502.500.160.0012,736.0000.3460.16100.20
544.960.170.0012,736.0000.3750.17100.30
587.410.170.0012,736.0000.4040.17100.40
629.870.180.0012,736.0000.4340.18100.50
672.330.180.0012,736.0000.4630.18100.60
714.790.180.0012,736.0000.4920.18100.70
757.250.190.0012,736.0000.5210.19100.80
799.700.190.0012,736.0000.5510.19100.90
842.160.200.0012,736.0000.5800.20101.00
884.620.200.0012,736.0000.6090.20101.10
927.070.210.0012,736.0000.6380.21101.20
969.530.210.0012,736.0000.6680.21101.30
Page 41 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
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[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1
Return Event: 100 yearsSubsection: Elevation-Volume-Flow Table (Pond)
2S/t + O
(ft³/s)
Flow (Total)
(ft³/s)
Infiltration
(ft³/s)
Area
(ft²)
Storage
(ac-ft)
Outflow
(ft³/s)
Elevation
(ft)
1,011.990.210.0012,736.0000.6970.21101.40
1,054.450.220.0012,736.0000.7260.22101.50
1,096.900.220.0012,736.0000.7550.22101.60
1,139.360.220.0012,736.0000.7850.22101.70
1,181.820.230.0012,736.0000.8140.23101.80
1,224.270.230.0012,736.0000.8430.23101.90
1,266.730.230.0012,736.0000.8720.23102.00
1,309.190.240.0012,736.0000.9010.24102.10
1,351.640.240.0012,736.0000.9310.24102.20
1,394.100.240.0012,736.0000.9600.24102.30
1,436.560.250.0012,736.0000.9890.25102.40
1,479.010.250.0012,736.0001.0180.25102.50
1,521.470.250.0012,736.0001.0480.25102.60
1,563.930.260.0012,736.0001.0770.26102.70
1,606.380.260.0012,736.0001.1060.26102.80
1,648.840.260.0012,736.0001.1350.26102.90
1,691.300.270.0012,736.0001.1650.27103.00
1,716.770.270.0012,736.0001.1820.27103.06
1,733.940.460.0012,736.0001.1940.46103.10
1,777.471.530.0012,736.0001.2231.53103.20
1,821.192.810.0012,736.0001.2522.81103.30
1,864.914.070.0012,736.0001.2824.07103.40
1,908.845.540.0012,736.0001.3115.54103.50
1,952.566.810.0012,736.0001.3406.81103.60
1,996.268.060.0012,736.0001.3698.06103.70
2,039.989.330.0012,736.0001.3999.33103.80
2,083.4810.370.0012,736.0001.42810.37103.90
2,127.0711.510.0012,736.0001.45711.51104.00
2,153.1312.100.0012,736.0001.47512.10104.06
Page 42 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
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[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (IN)
Return Event: 100 yearsSubsection: Level Pool Pond Routing Summary
Infiltration
No InfiltrationInfiltration Method
(Computed)
Initial Conditions
ft99.00Elevation (Water Surface,
Initial)
ac-ft0.003Volume (Initial)
ft³/s0.08Flow (Initial Outlet)
ft³/s0.00Flow (Initial Infiltration)
ft³/s0.08Flow (Initial, Total)
min1.000Time Increment
Inflow/Outflow Hydrograph Summary
ft³/s31.00Flow (Peak In)min248.000Time to Peak (Flow, In)
ft³/s1.55Flow (Peak Outlet)min308.000Time to Peak (Flow, Outlet)
ft103.20Elevation (Water Surface,
Peak)
ac-ft1.224Volume (Peak)
Mass Balance (ac-ft)
ac-ft0.003Volume (Initial)
ac-ft1.430Volume (Total Inflow)
ac-ft0.000Volume (Total Infiltration)
ac-ft1.034Volume (Total Outlet
Outflow)
ac-ft0.399Volume (Retained)
ac-ft0.000Volume (Unrouted)
%0.0Error (Mass Balance)
Page 43 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
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[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Scenario: EX10
Storm Event:Label: 1 (IN)
Return Event: 100 yearsSubsection: Pond Inflow Summary
Summary for Hydrograph Addition at '1'
Upstream NodeUpstream Link
CM-1<Catchment to Outflow Node>
Node Inflows
Flow (Peak)
(ft³/s)
Time to Peak
(min)
Volume
(ac-ft)
ElementInflow Type
31.00248.0001.430CM-1Flow (From)
31.00248.0001.4301Flow (In)
Page 44 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
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Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
Detention Vault
Index
User Notifications...2
U
Outlet#1 (Outlet Input Data, 100 years (EX10))...37, 38, 39, 40
Outlet#1 (Outlet Input Data)...
O
Master Network Summary...3
M
CM-1 (Read Hydrograph, 100 years (EX10))...4
CM-1 (Read Hydrograph)...
C
1 (Volume Equations, 100 years (EX10))...36
1 (Volume Equations)...
1 (Time vs. Volume, 100 years (EX10))...20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30,
31, 32, 33, 34
1 (Time vs. Volume)...
1 (OUT) (Time vs. Elevation, 100 years (EX10))...5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19
1 (OUT) (Time vs. Elevation)...
1 (IN) (Pond Inflow Summary, 100 years (EX10))...44
1 (IN) (Pond Inflow Summary)...
1 (IN) (Level Pool Pond Routing Summary, 100 years (EX10))...43
1 (IN) (Level Pool Pond Routing Summary)...
1 (Elevation-Volume-Flow Table (Pond), 100 years (EX10))...41, 42
1 (Elevation-Volume-Flow Table (Pond))...
1 (Elevation-Area Volume Curve, 100 years (EX10))...35
1 (Elevation-Area Volume Curve)...
1
Page 45 of 4527 Siemon Company Drive Suite 200 W
Watertown, CT 06795 USA +1-203-755-1666
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[10.02.00.01]
Bentley Systems, Inc. Haestad Methods Solution
CenterVault.ppc
APPENDIX 6
Drainage Exhibits
CITY OF SAN DIEGO
NAKANO
T O R
T
O
R
T O R
T
O
R
T O R
T
O
R
T O R
T
O
R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
T O R
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
TOR
T O RTORTORTORTOR
T O R T O R T O R T O R T O R T O R
RT
CITY OF CHULA VISTA
NAKANO
APPENDIX 7
FEMA Approval Letter for LOMA
Case No.: 20-09-1145ADate: LOMA
Federal Emergency Management Agency
Washington, D.C. 20472
Page 1 of 2 May 22, 2020
APPROXIMATE LATITUDE & LONGITUDE OF PROPERTY:32.588896, -117.033960
SOURCE OF LAT & LONG: LOMA LOGIC
COMMUNITY AND MAP PANEL INFORMATION LEGAL PROPERTY DESCRIPTION
COMMUNITY
AFFECTED
MAP PANEL
NUMBER: 06073C2158G
DATE: 5/16/2012
FLOODING SOURCE: OTAY RIVER
CITY OF CHULA VISTA, SAN
DIEGO COUNTY, CALIFORNIA
A portion of Section 24, Township 18 South, Range 2 West, San
Bernardino Meridian, as described in the Grant Deed recorded as
Document No. 2004-0777337, Pages 13994 and 13995, in the Office of
the County Recorder, San Diego County, California (APN: 624-071-02)
COMMUNITY NO.: 065021
DATUM: NAD 83
DETERMINATION DOCUMENT (REMOVAL)
LETTER OF MAP AMENDMENT
DETERMINATION
STREET FLOOD
ZONE
LOWEST
LOT
ELEVATION
(NAVD 88)
BLOCK/
SECTION
SUBDIVISIONLOT
OUTCOME 1% ANNUAL
CHANCE
FLOOD
ELEVATION
(NAVD 88)
LOWEST
ADJACENT
GRADE
ELEVATION
(NAVD 88)
WHAT IS
REMOVED FROM
THE SFHA
--97.9 feet----X
(shaded)
Property------
Special Flood Hazard Area (SFHA) - The SFHA is an area that would be inundated by the flood having a 1-percent chance of being equaled or
exceeded in any given year (base flood).
ADDITIONAL CONSIDERATIONS (Please refer to the appropriate section on Attachment 1 for the additional considerations listed below.)
STATE LOCAL CONSIDERATIONS
This document provides the Federal Emergency Management Agency's determination regarding a request for a Letter of Map Amendment for
the property described above. Using the information submitted and the effective National Flood Insurance Program (NFIP) map, we have
determined that the property(ies) is/are not located in the SFHA, an area inundated by the flood having a 1-percent chance of being equaled or
exceeded in any given year (base flood). This document amends the effective NFIP map to remove the subject property from the SFHA located
on the effective NFIP map; therefore, the Federal mandatory flood insurance requirement does not apply. However, the lender has the option to
continue the flood insurance requirement to protect its financial risk on the loan. A Preferred Risk Policy (PRP) is available for buildings located
outside the SFHA. Information about the PRP and how one can apply is enclosed.
This determination is based on the flood data presently available. The enclosed documents provide additional information regarding this
determination. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at (877)
336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency Management Agency, Engineering Library, 3601 Eisenhower Ave
Ste 500, Alexandria, VA 22304-6426.
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
Case No.: 20-09-1145ADate: LOMA
Federal Emergency Management Agency
Washington, D.C. 20472
Page 2 of 2 May 22, 2020
LETTER OF MAP AMENDMENT
DETERMINATION DOCUMENT (REMOVAL)
ATTACHMENT 1 (ADDITIONAL CONSIDERATIONS)
STATE AND LOCAL CONSIDERATIONS (This Additional Consideration applies to all properties in the
LOMA DETERMINATION DOCUMENT (REMOVAL))
Please note that this document does not override or supersede any State or local procedural or substantive
provisions which may apply to floodplain management requirements associated with amendments to State or
local floodplain zoning ordinances, maps, or State or local procedures adopted under the National Flood
Insurance Program.
This attachment provides additional information regarding this request. If you have any questions about this attachment, please contact the
FEMA Map Information eXchange (FMIX) toll free at (877) 336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency
Management Agency, Engineering Library, 3601 Eisenhower Ave Ste 500, Alexandria, VA 22304-6426.
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
MS. CHELISA PACK
PROJECT DESIGN CONSULTANTS
701 B STREET
SUITE 800
SAN DIEGO, CA 92101
CASE NO.: 20-09-1145A
COMMUNITY:CITY OF CHULA VISTA, SAN DIEGO
COUNTY, CALIFORNIA
COMMUNITY NO.: 065021
May 22, 2020
Washington, D.C. 20472
Federal Emergency Management Agency
DEAR MS. PACK:
This is in reference to a request that the Federal Emergency Management Agency (FEMA) determine
if the property described in the enclosed document is located within an identified Special Flood
Hazard Area, the area that would be inundated by the flood having a 1-percent chance of being equaled
or exceeded in any given year (base flood), on the effective National Flood Insurance Program (NFIP)
map. Using the information submitted and the effective NFIP map, our determination is shown on the
attached Letter of Map Amendment (LOMA) Determination Document. This determination document
provides additional information regarding the effective NFIP map, the legal description of the property
and our determination.
Additional documents are enclosed which provide information regarding the subject property and
LOMAs. Please see the List of Enclosures below to determine which documents are enclosed. Other
attachments specific to this request may be included as referenced in the Determination /Comment
document. If you have any questions about this letter or any of the enclosures, please contact the
FEMA Map Information eXchange (FMIX) toll free at (877) 336-2627 (877-FEMA MAP) or by letter
addressed to the Federal Emergency Management Agency, Engineering Library, 3601 Eisenhower Ave
Ste 500, Alexandria, VA 22304-6426.
Sincerely,
LIST OF ENCLOSURES:
LOMA DETERMINATION DOCUMENT (REMOVAL)
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
State/Commonwealth NFIP Coordinator
Community Map Repository
Region
cc:
ADDITIONAL INFORMATION REGARDING
LETTERS OF MAP AMENDMENT
When making determinations on requests for Letters of Map Amendment (LOMAs), the Department of
Homeland Security’s Federal Emergency Management Agency (FEMA) bases its determination on the
flood hazard information available at the time of the determination. Requesters should be aware that flood
conditions may change or new information may be generated that would supersede FEMA's determination.
In such cases, the community will be informed by letter.
Requesters also should be aware that removal of a property (parcel of land or structure) from the Special
Flood Hazard Area (SFHA) means FEMA has determined the property is not subject to inundation by the
flood having a 1-percent chance of being equaled or exceeded in any given year (base flood). This does not
mean the property is not subject to other flood hazards. The property could be inundated by a flood with a
magnitude greater than the base flood or by localized flooding not shown on the effective National Flood
Insurance Program (NFIP) map.
The effect of a LOMA is it removes the Federal requirement for the lender to require flood insurance
coverage for the property described. The LOMA is not a waiver of the condition that the property owner
maintain flood insurance coverage for the property. Only the lender can waive the flood insurance purchase
requirement because the lender imposed the requirement. The property owner must request and receive a
written waiver from the lender before canceling the policy. The lender may determine, on its own as a
business decision, that it wishes to continue the flood insurance requirement to protect its financial risk on
the loan.
The LOMA provides FEMA's comment on the mandatory flood insurance requirements of the NFIP as they
apply to a particular property. A LOMA is not a building permit, nor should it be construed as such. Any
development, new construction, or substantial improvement of a property impacted by a LOMA must
comply with all applicable State and local criteria and other Federal criteria.
If a lender releases a property owner from the flood insurance requirement, and the property owner decides
to cancel the policy and seek a refund, the NFIP will refund the premium paid for the current policy year,
provided that no claim is pending or has been paid on the policy during the current policy year. The
property owner must provide a written waiver of the insurance requirement from the lender to the property
insurance agent or company servicing his or her policy. The agent or company will then process the refund
request.
Even though structures are not located in an SFHA, as mentioned above, they could be flooded by a flooding
event with a greater magnitude than the base flood. In fact, more than 25 percent of all claims paid by the
NFIP are for policies for structures located outside the SFHA in Zones B, C, X (shaded), or X (unshaded).
More than one-fourth of all policies purchased under the NFIP protect structures located in these zones.
The risk to structures located outside SFHAs is just not as great as the risk to structures located in SFHAs.
Finally, approximately 90 percent of all federally declared disasters are caused by flooding, and homeowners
insurance does not provide financial protection from this flooding. Therefore, FEMA encourages the
widest possible coverage under the NFIP.
LOMAENC-1 (LOMA Removal)
The NFIP offers two types of flood insurance policies to property owners: the low-cost Preferred Risk
Policy (PRP) and the Standard Flood Insurance Policy (SFIP). The PRP is available for 1- to 4-family
residential structures located outside the SFHA with little or no loss history. The PRP is available for
townhouse/rowhouse-type structures, but is not available for other types of condominium units. The SFIP is
available for all other structures. Additional information on the PRP and how a property owner can quality
for this type of policy may be obtained by calling the Flood Insurance Information Hotline, toll free, at 1-800-
427-4661. Before making a final decision about flood insurance coverage, FEMA strongly encourages
property owners to discuss their individual flood risk situations and insurance needs with an insurance agent
or company.
FEMA has established "Grandfather" rules to benefit flood insurance policyholders who have maintained
continuous coverage. Property owners may wish to note also that, if they live outside but on the fringe of the
SFHA shown on an effective NFIP map and the map is revised to expand the SFHA to include their
structure(s), their flood insurance policy rates will not increase as long as the coverage for the affected
structure(s) has been continuous. Property owners would continue to receive the lower insurance policy
rates.
LOMAs are based on minimum criteria established by the NFIP. State, county, and community officials,
based on knowledge of local conditions and in the interest of safety, may set higher standards for
construction in the SFHA. If a State, county, or community has adopted more restrictive and comprehensive
floodplain management criteria, these criteria take precedence over the minimum Federal criteria.
In accordance with regulations adopted by the community when it made application to join the NFIP, letters
issued to amend an NFIP map must be attached to the community's official record copy of the map. That
map is available for public inspection at the community's official map repository. Therefore, FEMA sends
copies of all such letters to the affected community's official map repository.
When a restudy is undertaken, or when a sufficient number of revisions or amendments occur on particular
map panels, FEMA initiates the printing and distribution process for the affected panels. FEMA notifies
community officials in writing when affected map panels are being physically revised and distributed. In
such cases, FEMA attempts to reflect the results of the LOMA on the new map panel. If the results of
particular LOMAs cannot be reflected on the new map panel because of scale limitations, FEMA notifies the
community in writing and revalidates the LOMAs in that letter. LOMAs revalidated in this way usually will
become effective 1 day after the effective date of the revised map.
TABLE OF CONTENTS
1. INTRODUCTION .................................................................................................................. 1
2. SUMMARY OF METHODOLOGY ...................................................................................... 1
2.1 Existing Condition of the Property ...................................................................................... 1
2.2 Floodplain Base Flood Elevation Comparison .................................................................... 2
3. CONCLUSIONS..................................................................................................................... 2
APPENDICES
1 FEMA Forms, Package MT-1
2 Exhibits
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\LOMA\4409.02 LOMA.docx
1
1. INTRODUCTION
This Letter of Map Amendment (LOMA) has been prepared in order to certify that the existing
property within the Nakano project in the City of Chula Vista, California is above the flood
elevations as indicated on the NFIP map.
The purpose of the application is to demonstrate that the existing elevations of the Nakano property
are above the flood elevations indicated by Zone AE as shown in the FIRM Panel No.
06073C2158G, effective date May 16, 2012. The Zone AE floodplain extends along the north
portion of the site with water surface elevations ranging from 83.8 to 92.7 ft. MSL (NGVD 29).
Note that there a 2.17 conversion from NAVD88 to NGVD29 datum. The elevations listed on the
exhibit show elevations per the NGVD29 datum.
2. SUMMARY OF METHODOLOGY
The following summarizes how the base flood elevations were determined in order to ensure the
existing elevations are above the base flood and enable their removal from the special flood hazard
area mapping.
2.1 Existing Condition of the Property
The Nakano site consists of approximately 23.8 acres of existing hillside and grass land use located
within the Otay Mesa neighborhood of the City of Chula Vista. The site is bounded by Kaiser
Permanente medical offices to the South, Interstate 805 to the West, an existing residential site to
the east and Otay River to the North. Existing condition onsite includes grassland, hillside, utilities
facilities, and a small dirt paths traversing the property.
Per the FIRM panel, in the existing condition, the floodplain encroaches into the site along the
northern extents of the project boundary. Along the northern portion of the property the site is
affected by Zone AE. Refer to Exhibit A-1 for the existing floodplain exhibit depicting the
relationship of the floodplain to the property.
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\LOMA\4409.02 LOMA.docx
2
2.2 Floodplain Base Flood Elevation Comparison
The base flood elevations (BFE) were taken from the FEMA FIRM Panel No. 06073C2158G,
effective date May 16, 2012. The Zone AE floodplain extends along the north portion of the site
with water surface elevations ranging from 83.8 to 92.7 ft. MSL (NGVD 29). The lowest point on
the site along the northern property line is 95.7, three feet above the highest floodplain elevation
at the northwest corner of the site of 92.7. This comparison of the worst case scenario of the lowest
elevation on the existing property is still three feet higher than the highest floodway elevation at
any point on site indicates that the entire site can be removed from the special flood hazard area
mapping.
3. CONCLUSIONS
The existing property elevations indicate that the entire site is higher than the determined Zone AE
special flood hazard area base flood elevations for the Otay River. Therefore, this report supports
a recommendation that the entire property identified be removed from the 100-year floodplain
limits.
APPENDIX 1
FEMA Forms, Package MT-1
MT-1 Form 1
Property Information
DEPARTMENT OF HOMELAND SECURITY -FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B. NO. 1660-0015
PROPERTY INFORMATION FORM Expires February 28, 2014
PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this data collection is estimated to average 1.63 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources, gathering and maintaining the needed data, and completing and submitting the form. This collection is required to obtain or retain
benefits. You are not required to respond to this collection of information unless a valid OMB control number is displayed on this form. Send comments regarding the
accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Department of Homeland Security, Federal
Emergency Management Agency, 1800 South Bell Street, Arlington, VA 20598-3005, Paperwork Reduction Project (1660-0015). NOTE: Do not send your completed
form to this address.
This form may be completed by the property owner, property owner’s agent, licensed land surveyor, or registered professional engineer to support a request for a
Letter of Map Amendment (LOMA), Conditional Letter of Map Amendment (CLOMA), Letter of Map Revision Based on Fill (LOMR-F), or Conditional Letter of Map
Revision Based on Fill (CLOMR-F) for existing or proposed, single or multiple lots/structures. In order to process your request, all information on this form must be
completed in its entirety, unless stated as optional. Incomplete submissions will result in processing delays. Please check the item below that describes your request:
LOMA A letter from DHS-FEMA stating that an existing structure or parcel of land that has not been elevated
by fill (natural grade) would not be inundated by the base flood.
CLOMA A letter from DHS-FEMA stating that a proposed structure that is not to be elevated by fill (natural
grade) would not be inundated by the base flood if built as proposed.
LOMR-F A letter from DHS-FEMA stating that an existing structure or parcel of land that has been elevated by
fill would not be inundated by the base flood.
CLOMR-F
A letter from DHS-FEMA stating that a parcel of land or proposed structure that will be elevated by fill
would not be inundated by the base flood if fill is placed on the parcel as proposed or the structure is
built as proposed.
Fill is defined as material from any source (including the subject property) placed that raises the ground to or above the Base Flood Elevation (BFE). The common
construction practice of removing unsuitable existing material (topsoil) and backfilling with select structural material is not considered the placement of fill if the
practice does not alter the existing (natural grade) elevation, which is at or above the BFE. Fill that is placed before the date of the first National Flood Insurance
Program (NFIP) map showing the area in a Special Flood Hazard Area (SFHA) is considered natural grade.
Has fill been placed on your property to raise
ground that was previously below the BFE? Yes No If yes, when was fill placed? /
month/year
Will fill be placed on your property to raise
ground that is below the BFE? Yes* No If yes, when will fill be placed? /
month/year
* If yes, Endangered Species Act (ESA) compliance must be documented to FEMA prior to issuance
of the CLOMR-F determination (please refer page 4 to the MT-1 instructions).
1.Street Address of the Property (if request is for multiple structures or units, please attach additional sheet referencing ea ch address and enter
street names below):
2.Legal description of Property (Lot, Block, Subdivision or abbreviated description from the Deed):
3.Are you requesting that a flood zone determination be completed for (check one):
Structures on the property? What are the dates of construction? _______________ (MM/YYYY)
A portion of land within the bounds of the property? (A certified metes and bounds description and map of the area to be
removed, certified by a licensed land surveyor or registered professional engineer, are required. For the preferred format of
metes and bounds descriptions, please refer to the MT-1 Form 1 Instructions.)
The entire legally recorded property?
4.Is this request for a (check one):
Single structure
Single lot
Multiple structures (How many structures are involved in your request? List the number: _______)
Multiple lots (How many lots are involved in your request? List the number: _______)
DHS - FEMA Form 086-0-26, FEB 11 Property Information Form MT-1 Form 1 Page 1 of 2
LEGAL DESCRIPTION
PARCEL1:
THAT PORTION OF THE NORTHEAST QUARTER OF THE SOUTHW EST QUARTER OF
SECTION 24, TOWNSHIP 18 SOUTH, RANGE 2 WEST, SAN BERNARDINO MERIDIAN IN
THE CITY OF CHULA VISTA, COUNTY OF SAN DIEGO, STATE OF CALIFORNIA,
ACCORDING TO THE OFFICIAL PLAT THEREOF DESCRIBED AS FOLLOWS:
BEGINNING AT THE SOUTHEAST CORNER OF SAID NORTHEAST QUARTER OF THE
SOUTHEAST QUARTER; THENCE ALONG THE SOUTH LINE THEREOF SOUTH 89°42’04”
WEST, 1069.30 FEET TO THE EASTERLY LINE OF FREEWAY DESCRIBED IN FINAL
ORDER OF CONDEMNATION RECORDED JULY 22, 1968 AS FILE NO. 123499 OFFICAL
RECORDS; THENCE ALONG SAID EASTERLY LINE NORTH 3°47’10” EAST, 918.10 FEET;
THENCE NORTH 80°52”26” EAST, 1030.62 FEET TO THE EAST LINE OF SAID SECTION:
THENCE ALONG SAID EAST LINE SOUTH 0°28’33” WEST, 1074.02 FEET TO THE POINT
OF BEGINNING.
PARCEL 2:
AN EASEMENT FOR ROAD AND WATER PIPELINE PURPOSES 15 FEET WIDE ALONG
THE EXSTING TRAVELED ROAD ACROSS THE SOUTHEAST QUARTER OF THE
NORTHEAST QUARTER AND THAT PORTION OF THE NORTHEAST QUARTER OF THE
SOUTHEAST QUARTER OF SAID SECTION LYING NORTHERLY OF THE NORTHERLY
LINE OF PARCEL 1 ABOVE.
EXCEPTING THAT PORTION LYING WITHIN SAID FREEWAY AND OTAY VALLEY ROAD.
Annotated FIRM Panel
ANNOTATED FIRM
PROJECT
SITE
Grant Deed
MT-1 Form 2
Elevation Form
APPENDIX 2
Exhibits
CITY OF CHULA VISTA
NAKANO
APPENDIX 7
FEMA Approval Letter for LOMA
Case No.: 20-09-1145ADate: LOMA
Federal Emergency Management Agency
Washington, D.C. 20472
Page 1 of 2 May 22, 2020
APPROXIMATE LATITUDE & LONGITUDE OF PROPERTY:32.588896, -117.033960
SOURCE OF LAT & LONG: LOMA LOGIC
COMMUNITY AND MAP PANEL INFORMATION LEGAL PROPERTY DESCRIPTION
COMMUNITY
AFFECTED
MAP PANEL
NUMBER: 06073C2158G
DATE: 5/16/2012
FLOODING SOURCE: OTAY RIVER
CITY OF CHULA VISTA, SAN
DIEGO COUNTY, CALIFORNIA
A portion of Section 24, Township 18 South, Range 2 West, San
Bernardino Meridian, as described in the Grant Deed recorded as
Document No. 2004-0777337, Pages 13994 and 13995, in the Office of
the County Recorder, San Diego County, California (APN: 624-071-02)
COMMUNITY NO.: 065021
DATUM: NAD 83
DETERMINATION DOCUMENT (REMOVAL)
LETTER OF MAP AMENDMENT
DETERMINATION
STREET FLOOD
ZONE
LOWEST
LOT
ELEVATION
(NAVD 88)
BLOCK/
SECTION
SUBDIVISIONLOT
OUTCOME 1% ANNUAL
CHANCE
FLOOD
ELEVATION
(NAVD 88)
LOWEST
ADJACENT
GRADE
ELEVATION
(NAVD 88)
WHAT IS
REMOVED FROM
THE SFHA
--97.9 feet----X
(shaded)
Property------
Special Flood Hazard Area (SFHA) - The SFHA is an area that would be inundated by the flood having a 1-percent chance of being equaled or
exceeded in any given year (base flood).
ADDITIONAL CONSIDERATIONS (Please refer to the appropriate section on Attachment 1 for the additional considerations listed below.)
STATE LOCAL CONSIDERATIONS
This document provides the Federal Emergency Management Agency's determination regarding a request for a Letter of Map Amendment for
the property described above. Using the information submitted and the effective National Flood Insurance Program (NFIP) map, we have
determined that the property(ies) is/are not located in the SFHA, an area inundated by the flood having a 1-percent chance of being equaled or
exceeded in any given year (base flood). This document amends the effective NFIP map to remove the subject property from the SFHA located
on the effective NFIP map; therefore, the Federal mandatory flood insurance requirement does not apply. However, the lender has the option to
continue the flood insurance requirement to protect its financial risk on the loan. A Preferred Risk Policy (PRP) is available for buildings located
outside the SFHA. Information about the PRP and how one can apply is enclosed.
This determination is based on the flood data presently available. The enclosed documents provide additional information regarding this
determination. If you have any questions about this document, please contact the FEMA Map Information eXchange (FMIX) toll free at (877)
336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency Management Agency, Engineering Library, 3601 Eisenhower Ave
Ste 500, Alexandria, VA 22304-6426.
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
Case No.: 20-09-1145ADate: LOMA
Federal Emergency Management Agency
Washington, D.C. 20472
Page 2 of 2 May 22, 2020
LETTER OF MAP AMENDMENT
DETERMINATION DOCUMENT (REMOVAL)
ATTACHMENT 1 (ADDITIONAL CONSIDERATIONS)
STATE AND LOCAL CONSIDERATIONS (This Additional Consideration applies to all properties in the
LOMA DETERMINATION DOCUMENT (REMOVAL))
Please note that this document does not override or supersede any State or local procedural or substantive
provisions which may apply to floodplain management requirements associated with amendments to State or
local floodplain zoning ordinances, maps, or State or local procedures adopted under the National Flood
Insurance Program.
This attachment provides additional information regarding this request. If you have any questions about this attachment, please contact the
FEMA Map Information eXchange (FMIX) toll free at (877) 336-2627 (877-FEMA MAP) or by letter addressed to the Federal Emergency
Management Agency, Engineering Library, 3601 Eisenhower Ave Ste 500, Alexandria, VA 22304-6426.
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
MS. CHELISA PACK
PROJECT DESIGN CONSULTANTS
701 B STREET
SUITE 800
SAN DIEGO, CA 92101
CASE NO.: 20-09-1145A
COMMUNITY:CITY OF CHULA VISTA, SAN DIEGO
COUNTY, CALIFORNIA
COMMUNITY NO.: 065021
May 22, 2020
Washington, D.C. 20472
Federal Emergency Management Agency
DEAR MS. PACK:
This is in reference to a request that the Federal Emergency Management Agency (FEMA) determine
if the property described in the enclosed document is located within an identified Special Flood
Hazard Area, the area that would be inundated by the flood having a 1-percent chance of being equaled
or exceeded in any given year (base flood), on the effective National Flood Insurance Program (NFIP)
map. Using the information submitted and the effective NFIP map, our determination is shown on the
attached Letter of Map Amendment (LOMA) Determination Document. This determination document
provides additional information regarding the effective NFIP map, the legal description of the property
and our determination.
Additional documents are enclosed which provide information regarding the subject property and
LOMAs. Please see the List of Enclosures below to determine which documents are enclosed. Other
attachments specific to this request may be included as referenced in the Determination /Comment
document. If you have any questions about this letter or any of the enclosures, please contact the
FEMA Map Information eXchange (FMIX) toll free at (877) 336-2627 (877-FEMA MAP) or by letter
addressed to the Federal Emergency Management Agency, Engineering Library, 3601 Eisenhower Ave
Ste 500, Alexandria, VA 22304-6426.
Sincerely,
LIST OF ENCLOSURES:
LOMA DETERMINATION DOCUMENT (REMOVAL)
Luis V. Rodriguez, P.E., Director
Engineering and Modeling Division
Federal Insurance and Mitigation Administration
State/Commonwealth NFIP Coordinator
Community Map Repository
Region
cc:
ADDITIONAL INFORMATION REGARDING
LETTERS OF MAP AMENDMENT
When making determinations on requests for Letters of Map Amendment (LOMAs), the Department of
Homeland Security’s Federal Emergency Management Agency (FEMA) bases its determination on the
flood hazard information available at the time of the determination. Requesters should be aware that flood
conditions may change or new information may be generated that would supersede FEMA's determination.
In such cases, the community will be informed by letter.
Requesters also should be aware that removal of a property (parcel of land or structure) from the Special
Flood Hazard Area (SFHA) means FEMA has determined the property is not subject to inundation by the
flood having a 1-percent chance of being equaled or exceeded in any given year (base flood). This does not
mean the property is not subject to other flood hazards. The property could be inundated by a flood with a
magnitude greater than the base flood or by localized flooding not shown on the effective National Flood
Insurance Program (NFIP) map.
The effect of a LOMA is it removes the Federal requirement for the lender to require flood insurance
coverage for the property described. The LOMA is not a waiver of the condition that the property owner
maintain flood insurance coverage for the property. Only the lender can waive the flood insurance purchase
requirement because the lender imposed the requirement. The property owner must request and receive a
written waiver from the lender before canceling the policy. The lender may determine, on its own as a
business decision, that it wishes to continue the flood insurance requirement to protect its financial risk on
the loan.
The LOMA provides FEMA's comment on the mandatory flood insurance requirements of the NFIP as they
apply to a particular property. A LOMA is not a building permit, nor should it be construed as such. Any
development, new construction, or substantial improvement of a property impacted by a LOMA must
comply with all applicable State and local criteria and other Federal criteria.
If a lender releases a property owner from the flood insurance requirement, and the property owner decides
to cancel the policy and seek a refund, the NFIP will refund the premium paid for the current policy year,
provided that no claim is pending or has been paid on the policy during the current policy year. The
property owner must provide a written waiver of the insurance requirement from the lender to the property
insurance agent or company servicing his or her policy. The agent or company will then process the refund
request.
Even though structures are not located in an SFHA, as mentioned above, they could be flooded by a flooding
event with a greater magnitude than the base flood. In fact, more than 25 percent of all claims paid by the
NFIP are for policies for structures located outside the SFHA in Zones B, C, X (shaded), or X (unshaded).
More than one-fourth of all policies purchased under the NFIP protect structures located in these zones.
The risk to structures located outside SFHAs is just not as great as the risk to structures located in SFHAs.
Finally, approximately 90 percent of all federally declared disasters are caused by flooding, and homeowners
insurance does not provide financial protection from this flooding. Therefore, FEMA encourages the
widest possible coverage under the NFIP.
LOMAENC-1 (LOMA Removal)
The NFIP offers two types of flood insurance policies to property owners: the low-cost Preferred Risk
Policy (PRP) and the Standard Flood Insurance Policy (SFIP). The PRP is available for 1- to 4-family
residential structures located outside the SFHA with little or no loss history. The PRP is available for
townhouse/rowhouse-type structures, but is not available for other types of condominium units. The SFIP is
available for all other structures. Additional information on the PRP and how a property owner can quality
for this type of policy may be obtained by calling the Flood Insurance Information Hotline, toll free, at 1-800-
427-4661. Before making a final decision about flood insurance coverage, FEMA strongly encourages
property owners to discuss their individual flood risk situations and insurance needs with an insurance agent
or company.
FEMA has established "Grandfather" rules to benefit flood insurance policyholders who have maintained
continuous coverage. Property owners may wish to note also that, if they live outside but on the fringe of the
SFHA shown on an effective NFIP map and the map is revised to expand the SFHA to include their
structure(s), their flood insurance policy rates will not increase as long as the coverage for the affected
structure(s) has been continuous. Property owners would continue to receive the lower insurance policy
rates.
LOMAs are based on minimum criteria established by the NFIP. State, county, and community officials,
based on knowledge of local conditions and in the interest of safety, may set higher standards for
construction in the SFHA. If a State, county, or community has adopted more restrictive and comprehensive
floodplain management criteria, these criteria take precedence over the minimum Federal criteria.
In accordance with regulations adopted by the community when it made application to join the NFIP, letters
issued to amend an NFIP map must be attached to the community's official record copy of the map. That
map is available for public inspection at the community's official map repository. Therefore, FEMA sends
copies of all such letters to the affected community's official map repository.
When a restudy is undertaken, or when a sufficient number of revisions or amendments occur on particular
map panels, FEMA initiates the printing and distribution process for the affected panels. FEMA notifies
community officials in writing when affected map panels are being physically revised and distributed. In
such cases, FEMA attempts to reflect the results of the LOMA on the new map panel. If the results of
particular LOMAs cannot be reflected on the new map panel because of scale limitations, FEMA notifies the
community in writing and revalidates the LOMAs in that letter. LOMAs revalidated in this way usually will
become effective 1 day after the effective date of the revised map.
TABLE OF CONTENTS
1. INTRODUCTION .................................................................................................................. 1
2. SUMMARY OF METHODOLOGY ...................................................................................... 1
2.1 Existing Condition of the Property ...................................................................................... 1
2.2 Floodplain Base Flood Elevation Comparison .................................................................... 2
3. CONCLUSIONS..................................................................................................................... 2
APPENDICES
1 FEMA Forms, Package MT-1
2 Exhibits
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\LOMA\4409.02 LOMA.docx
1
1. INTRODUCTION
This Letter of Map Amendment (LOMA) has been prepared in order to certify that the existing
property within the Nakano project in the City of Chula Vista, California is above the flood
elevations as indicated on the NFIP map.
The purpose of the application is to demonstrate that the existing elevations of the Nakano property
are above the flood elevations indicated by Zone AE as shown in the FIRM Panel No.
06073C2158G, effective date May 16, 2012. The Zone AE floodplain extends along the north
portion of the site with water surface elevations ranging from 83.8 to 92.7 ft. MSL (NGVD 29).
Note that there a 2.17 conversion from NAVD88 to NGVD29 datum. The elevations listed on the
exhibit show elevations per the NGVD29 datum.
2. SUMMARY OF METHODOLOGY
The following summarizes how the base flood elevations were determined in order to ensure the
existing elevations are above the base flood and enable their removal from the special flood hazard
area mapping.
2.1 Existing Condition of the Property
The Nakano site consists of approximately 23.8 acres of existing hillside and grass land use located
within the Otay Mesa neighborhood of the City of Chula Vista. The site is bounded by Kaiser
Permanente medical offices to the South, Interstate 805 to the West, an existing residential site to
the east and Otay River to the North. Existing condition onsite includes grassland, hillside, utilities
facilities, and a small dirt paths traversing the property.
Per the FIRM panel, in the existing condition, the floodplain encroaches into the site along the
northern extents of the project boundary. Along the northern portion of the property the site is
affected by Zone AE. Refer to Exhibit A-1 for the existing floodplain exhibit depicting the
relationship of the floodplain to the property.
P:\4409\Engr\Reports-4409.02-Nakano\Entitlement\LOMA\4409.02 LOMA.docx
2
2.2 Floodplain Base Flood Elevation Comparison
The base flood elevations (BFE) were taken from the FEMA FIRM Panel No. 06073C2158G,
effective date May 16, 2012. The Zone AE floodplain extends along the north portion of the site
with water surface elevations ranging from 83.8 to 92.7 ft. MSL (NGVD 29). The lowest point on
the site along the northern property line is 95.7, three feet above the highest floodplain elevation
at the northwest corner of the site of 92.7. This comparison of the worst case scenario of the lowest
elevation on the existing property is still three feet higher than the highest floodway elevation at
any point on site indicates that the entire site can be removed from the special flood hazard area
mapping.
3. CONCLUSIONS
The existing property elevations indicate that the entire site is higher than the determined Zone AE
special flood hazard area base flood elevations for the Otay River. Therefore, this report supports
a recommendation that the entire property identified be removed from the 100-year floodplain
limits.
APPENDIX 1
FEMA Forms, Package MT-1
MT-1 Form 1
Property Information
DEPARTMENT OF HOMELAND SECURITY -FEDERAL EMERGENCY MANAGEMENT AGENCY O.M.B. NO. 1660-0015
PROPERTY INFORMATION FORM Expires February 28, 2014
PAPERWORK BURDEN DISCLOSURE NOTICE
Public reporting burden for this data collection is estimated to average 1.63 hours per response. The burden estimate includes the time for reviewing instructions,
searching existing data sources, gathering and maintaining the needed data, and completing and submitting the form. This collection is required to obtain or retain
benefits. You are not required to respond to this collection of information unless a valid OMB control number is displayed on this form. Send comments regarding the
accuracy of the burden estimate and any suggestions for reducing this burden to: Information Collections Management, Department of Homeland Security, Federal
Emergency Management Agency, 1800 South Bell Street, Arlington, VA 20598-3005, Paperwork Reduction Project (1660-0015). NOTE: Do not send your completed
form to this address.
This form may be completed by the property owner, property owner’s agent, licensed land surveyor, or registered professional engineer to support a request for a
Letter of Map Amendment (LOMA), Conditional Letter of Map Amendment (CLOMA), Letter of Map Revision Based on Fill (LOMR-F), or Conditional Letter of Map
Revision Based on Fill (CLOMR-F) for existing or proposed, single or multiple lots/structures. In order to process your request, all information on this form must be
completed in its entirety, unless stated as optional. Incomplete submissions will result in processing delays. Please check the item below that describes your request:
LOMA A letter from DHS-FEMA stating that an existing structure or parcel of land that has not been elevated
by fill (natural grade) would not be inundated by the base flood.
CLOMA A letter from DHS-FEMA stating that a proposed structure that is not to be elevated by fill (natural
grade) would not be inundated by the base flood if built as proposed.
LOMR-F A letter from DHS-FEMA stating that an existing structure or parcel of land that has been elevated by
fill would not be inundated by the base flood.
CLOMR-F
A letter from DHS-FEMA stating that a parcel of land or proposed structure that will be elevated by fill
would not be inundated by the base flood if fill is placed on the parcel as proposed or the structure is
built as proposed.
Fill is defined as material from any source (including the subject property) placed that raises the ground to or above the Base Flood Elevation (BFE). The common
construction practice of removing unsuitable existing material (topsoil) and backfilling with select structural material is not considered the placement of fill if the
practice does not alter the existing (natural grade) elevation, which is at or above the BFE. Fill that is placed before the date of the first National Flood Insurance
Program (NFIP) map showing the area in a Special Flood Hazard Area (SFHA) is considered natural grade.
Has fill been placed on your property to raise
ground that was previously below the BFE? Yes No If yes, when was fill placed? /
month/year
Will fill be placed on your property to raise
ground that is below the BFE? Yes* No If yes, when will fill be placed? /
month/year
* If yes, Endangered Species Act (ESA) compliance must be documented to FEMA prior to issuance
of the CLOMR-F determination (please refer page 4 to the MT-1 instructions).
1.Street Address of the Property (if request is for multiple structures or units, please attach additional sheet referencing ea ch address and enter
street names below):
2.Legal description of Property (Lot, Block, Subdivision or abbreviated description from the Deed):
3.Are you requesting that a flood zone determination be completed for (check one):
Structures on the property? What are the dates of construction? _______________ (MM/YYYY)
A portion of land within the bounds of the property? (A certified metes and bounds description and map of the area to be
removed, certified by a licensed land surveyor or registered professional engineer, are required. For the preferred format of
metes and bounds descriptions, please refer to the MT-1 Form 1 Instructions.)
The entire legally recorded property?
4.Is this request for a (check one):
Single structure
Single lot
Multiple structures (How many structures are involved in your request? List the number: _______)
Multiple lots (How many lots are involved in your request? List the number: _______)
DHS - FEMA Form 086-0-26, FEB 11 Property Information Form MT-1 Form 1 Page 1 of 2
LEGAL DESCRIPTION
PARCEL1:
THAT PORTION OF THE NORTHEAST QUARTER OF THE SOUTHW EST QUARTER OF
SECTION 24, TOWNSHIP 18 SOUTH, RANGE 2 WEST, SAN BERNARDINO MERIDIAN IN
THE CITY OF CHULA VISTA, COUNTY OF SAN DIEGO, STATE OF CALIFORNIA,
ACCORDING TO THE OFFICIAL PLAT THEREOF DESCRIBED AS FOLLOWS:
BEGINNING AT THE SOUTHEAST CORNER OF SAID NORTHEAST QUARTER OF THE
SOUTHEAST QUARTER; THENCE ALONG THE SOUTH LINE THEREOF SOUTH 89°42’04”
WEST, 1069.30 FEET TO THE EASTERLY LINE OF FREEWAY DESCRIBED IN FINAL
ORDER OF CONDEMNATION RECORDED JULY 22, 1968 AS FILE NO. 123499 OFFICAL
RECORDS; THENCE ALONG SAID EASTERLY LINE NORTH 3°47’10” EAST, 918.10 FEET;
THENCE NORTH 80°52”26” EAST, 1030.62 FEET TO THE EAST LINE OF SAID SECTION:
THENCE ALONG SAID EAST LINE SOUTH 0°28’33” WEST, 1074.02 FEET TO THE POINT
OF BEGINNING.
PARCEL 2:
AN EASEMENT FOR ROAD AND WATER PIPELINE PURPOSES 15 FEET WIDE ALONG
THE EXSTING TRAVELED ROAD ACROSS THE SOUTHEAST QUARTER OF THE
NORTHEAST QUARTER AND THAT PORTION OF THE NORTHEAST QUARTER OF THE
SOUTHEAST QUARTER OF SAID SECTION LYING NORTHERLY OF THE NORTHERLY
LINE OF PARCEL 1 ABOVE.
EXCEPTING THAT PORTION LYING WITHIN SAID FREEWAY AND OTAY VALLEY ROAD.
Annotated FIRM Panel
ANNOTATED FIRM
PROJECT
SITE
Grant Deed
MT-1 Form 2
Elevation Form
APPENDIX 2
Exhibits
CITY OF CHULA VISTA
NAKANO
Project Name/______________________________________________________________
CCV BMP Manual
PDP SWQMP Template Date: March 2019
ATTACHMENT 6
Project's Geotechnical and Groundwater
Investigation Report
Attach project’s geotechnical and groundwater investigation report. Refer to Appendix C.4 to
determine the reporting requirements.
Project No. 07516-42-02
June 10, 2021
Tri Pointe Homes
13400 Sabre Springs Parkway, Suite 200
San Diego, California 92128
Attention: Ms. April Tornillo
Subject: UPDATE TO GEOTECHNICAL INVESTIGATION
NAKANO PROPERTY
CHULA VISTA, CALIFORNIA
References: 1. Update Geotechnical Investigation, Nakano Property, Chula Vista, California prepared
by Geocon Incorporated dated September 18, 2020 (Project No. 07516-42-02).
2. Grading and Storm Drain, Nakano, prepared by Civil Sense, Inc., dated June 9,
2021.
Dear Ms. Tornillo:
In accordance with the request of Civil Sense, Inc., we have prepared this update to the referenced
geotechnical investigation report for the subject project. Based on our review of Reference 2, the
recommendations contained in Referenced 1 remain applicable.
Should you have questions regarding this update letter, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Rodney C. Mikesell
GE 2533
RCM:arm
(e-mail) Addressee
UPDATE
GEOTECHNICAL INVESTIGATION
NAKANO PROPERTY
CHULA VISTA, CALIFORNIA
PREPARED FOR
PARDEE HOMES
SAN DIEGO, CALIFORNIA
SEPTEMBER 18, 2020
PROJECT NO. 07516-42-02
GROCON
INCORPORATED
GEOTECHNICAL • ENVIRONMENTAL MATERIALSO
6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159
Project No. 07516-42-02
September 18, 2020
Pardee Homes
13400 Sabre Springs Parkway, Suite 200
San Diego, California 92128
Attention: Ms. April Tornillo
Subject: UPDATE GEOTECHNICAL INVESTIGATION
NAKANO PROPERTY
CHULA VISTA, CALIFORNIA
Dear Ms. Tornillo:
In accordance with your authorization, we have prepared this update geotechnical investigation report
for the proposed residential development at the subject site. The site is underlain by undocumented
fill, colluvium, and alluvium, overlying Terrace Deposits and the Mission Valley Formation. The
accompanying report presents the results of our study and conclusions and recommendations regarding
geotechnical aspects of site development.
This report is based on previous and recent field observations in 2005 and 2020. It is our opinion,
based on the results of this study, that the subject site is suitable for development. The accompanying
report presents conclusions and recommendations regarding geotechnical aspects of development.
Should you have questions regarding this investigation, or if we may be of further service, please
contact the undersigned at your convenience.
Very truly yours,
GEOCON INCORPORATED
Rodney C. Mikesell
GE 2533
Rupert S. Adams
CEG 2561
RCM:RSA:dmc
(e-mail) Addressee
TABLE OF CONTENTS
1.PURPOSE AND SCOPE ...................................................................................................................... 1
2.SITE AND PROJECT DESCRIPTION ................................................................................................ 1
3.SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 2
3.1 Undocumented Fill (Qudf) ......................................................................................................... 2
3.2 Topsoil (Unmapped) ................................................................................................................... 3
3.3 Alluvium (Qal) ........................................................................................................................... 3
3.4 Colluvium (Qcol) ........................................................................................................................ 3
3.5 Terrace Deposits (Qt) ................................................................................................................. 3
3.6 Mission Valley Formation (Tmv) ............................................................................................... 3
4.GROUNDWATER ............................................................................................................................... 4
5.GEOLOGIC HAZARDS ...................................................................................................................... 4
5.1 Faulting and Seismicity .............................................................................................................. 4
5.2 Ground Rupture .......................................................................................................................... 6
5.3 Tsunamis and Seiches ................................................................................................................. 6
5.4 Flooding ...................................................................................................................................... 6
5.5 Liquefaction and Seismically Induced Settlement ...................................................................... 7
5.6 Landslides ................................................................................................................................... 7
5.7 Geologic Hazard Category ......................................................................................................... 7
6.CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 8
6.1 General ........................................................................................................................................ 8
6.2 Soil and Excavation Characteristics ........................................................................................... 9
6.3 Grading Recommendations ...................................................................................................... 10
6.4 Slopes ........................................................................................................................................ 12
6.5 Seismic Design Criteria (2019) ................................................................................................ 13
6.6 Foundations .............................................................................................................................. 15
6.7 Conventional Retaining Wall Recommendations ..................................................................... 21
6.8 Lateral Loading ......................................................................................................................... 24
6.9 Preliminary Pavement Recommendations ................................................................................ 25
6.10 Exterior Concrete Flatwork ...................................................................................................... 27
6.11 Slope Maintenance.................................................................................................................... 29
6.12 Storm Water Management ........................................................................................................ 29
6.13 Site Drainage and Moisture Protection ..................................................................................... 30
6.14 Grading and Foundation Plan Review ...................................................................................... 30
MAPS AND ILLUSTRATIONS
Figure 1, Vicinity Map
Figure 2, Geologic Map
Figures 3 and 4, Geologic Cross-Sections
Figure 5, Construction Detail for Lateral Extent of Removal
Figures 6 – 9, Slope Stability Analyses
APPENDIX A
FIELD INVESTIGATION
Figure A-1, Log of Large Diameter Boring
Figures A-2 – A-23, Logs of Exploratory Trenches
TABLE OF CONTENTS (Concluded)
APPENDIX B
LABORATORY TESTING
Table B-I, Summary of Laboratory Expansion Index Test Results
Table B-II, Summary of Laboratory Maximum Dry Density and Optimum Moisture Content Test Results
Table B-III, Summary of Laboratory Direct Shear Test Results
Table B-IV, Summary of Laboratory Water-Soluble Sulfate Test Results
Direct Shear Tests
APPENDIX C
STORM WATER MANAGEMENT RECOMMENDATIONS
APPENDIX D
RECOMMENDED GRADING SPECIFICATIONS
LIST OF REFERENCES
Project No. 07516-42-02 - 1 - September 18, 2020
UPDATE GEOTECHNICAL INVESTIGATION
1. PURPOSE AND SCOPE
This report presents the results of our update geotechnical investigation for the proposed 157-lot
residential development located on the Nakano Property northwest of Dennery Road, east of Interstate
805 (I-805), and south of the Otay River in Chula Vista, California (see Vicinity Map, Figure 1). The
purpose of our update investigation was to further evaluate subsurface soil and geologic conditions at
the site, and provide updated conclusions and recommendations pertaining to the geotechnical aspects
of developing the property as proposed.
The scope of our update investigation included a site reconnaissance, excavation of one large diameter
boring to a depth of 71 feet near the southwest corner of the property, performing infiltration testing in
the area of the proposed BMPs, and reviewing published and unpublished geologic literature and
reports (see List of References).
Appendix A presents a discussion of our field investigation. Included in Appendix A is our boring log
performed for this study and trench logs performed by Geocon Incorporated on the property during
previous studies. We performed laboratory tests on soil samples obtained from the large diameter
boring to evaluate pertinent physical properties for engineering analyses. The results of the laboratory
testing are presented in Appendix B. Also included in Appendix B is laboratory test results from our
previous study.
Site geologic conditions are depicted on Figure 2 (Geologic Map). The geologic contacts were plotted
on a base map provided by Civil Sense, Inc. Geologic cross sections are provided on Figures 3 and 4.
The conclusions and recommendations presented herein are based on our analysis of the data obtained
during the investigation, and our experience with similar soil and geologic conditions on this and
adjacent properties.
2. SITE AND PROJECT DESCRIPTION
The irregularly shaped, approximately 15-acre site is located northwest of the Dennery Road and
Regatta Lane intersection, east of I-805 in Chula Vista, California (see Vicinity Map, Figure 1). There
are no existing structures on the site, however several remnant building foundations are present.
Existing utilities at the site include 18- and 27-inch diameter sewer mains along the west and northern
portions of the property, respectively, high-voltage overhead electrical lines traversing the southern
portion of the site, and water lines and storm drain lines in the southeast corner of the property and a
reclaimed water line along the eastern property boundary. We understand the sewer main on the west
Project No. 07516-42-02 - 2 - September 18, 2020
property margin and the reclaimed water line on the eastern property margin will remain. The sewer
main that crosses the northern portion of the property will be removed.
Site topography is relatively flat, sloping from south to north towards the Otay River channel. A north-
facing natural slope, approximately 70 feet high is present along the south property boundary.
Elevations across the site range between approximately 95 and 180 feet above Mean Sea Level (MSL;
see Geologic Map, Figure 2).
A review of proposed grading plans by Civil Sense indicates proposed improvements will consist of
157 residential lots, a park, an underground stormwater management system, utilities, and street
improvements. Entrance to the property will be from a driveway at the southeast corner of the property
extending from Dennery Road. The proposed development includes cuts and fills up to 15 feet in sheet
graded areas and cut and fill slopes at inclinations of 2:1 (horizontal:vertical) with heights up to
55 feet.
The locations and descriptions of the site and proposed development are based on our recent site
reconnaissance, previous and recent field investigations, and our understanding of site development as
shown on the grading plan prepared by Civil Sense. If project details vary significantly from those
described, Geocon Incorporated should be contacted to review the changes and provide additional
analyses and/or revisions to this report, if warranted.
3. SOIL AND GEOLOGIC CONDITIONS
Based on the results of the field investigation, the site is underlain by four surficial soil types and one
formational unit, which are described below. Mapped geologic conditions are depicted on the
Geologic Map (Figure 2, map pocket) and Geologic Cross Sections (Figures 3 and 4). Trench and
boring logs are presented in Appendix A.
3.1 Undocumented Fill (Qudf)
We encountered undocumented fill in the trenches to depths of approximately 2 to 5 feet across the
majority of the site, increasing to greater than 18 feet in the northeast portion of the site. The
undocumented fill consists of very loose to moderately dense, sand with cobbles. Abundant debris
including pieces of plastic, asphalt concrete, concrete curb, brick and wood were also encountered in
the undocumented fill. The undocumented fill is compressible in its current state and will require
complete removal and recompaction to support compacted fill and/or proposed site improvements.
Project No. 07516-42-02 - 3 - September 18, 2020
3.2 Topsoil (Unmapped)
Topsoil covers the majority of the site and varies in thickness from 0.5 feet to 3 feet. The topsoil
typically consists of loose to moderately dense, dry to moist, sand, cobble and clay. The topsoil is
compressible and will require removal and recompaction to support compacted fill and/or proposed
site improvements.
3.3 Alluvium (Qal)
Alluvium is present in a drainage located at the southeast corner of the property. Alluvium was also
encountered in Trench T-20 beneath undocumented fill at the north end of the site. The alluvium
consists of stiff, damp, dark brown, sandy clay with gravel. The alluvium is compressible and will
require removal and recompaction to support compacted fill and/or proposed site improvements.
3.4 Colluvium (Qcol)
Colluvium is derived from weathering of the underlying bedrock materials at higher elevations and is
deposited by gravity and sheet-flow on the side slopes and canyon sidewalls. The observed thickness of
colluvium at the site was approximately 3 to 5 feet near trench T-6. The colluvium as encountered
consists of moderately dense, olive brown, clayey sand with cobbles. The colluvium is compressible in
its current state and will require removal and recompaction to support compacted fill and/or proposed
site improvements.
3.5 Terrace Deposits (Qt)
Quaternary-age Terrace Deposits were observed underlying artificial fill, topsoil, and alluvium in the
flatter portions of the site. The Terrace Deposits consist of moderately dense to very dense and firm to
very stiff, clayey gravel, clayey to cobbly sand, and silty to cobbly clay. Terrace Deposits are suitable
for support of compacted fill and/or structural loads.
3.6 Mission Valley Formation (Tmv)
Upper Eocene-age Mission Valley Formation was encountered in slopes along the southern portion of
the site. The Mission Valley Formation is predominantly a marine sandstone unit consisting of reddish
brown to tan, weak to friable, silty, fine- to medium-grained sandstone. The formation is typically
moderately to well cemented but is usually rippable with heavy duty excavation equipment; however,
localized cemented zones and concretions should be expected. The Mission Valley Formation is
suitable for the support of the compacted fill and structural loads.
Project No. 07516-42-02 - 4 - September 18, 2020
4. GROUNDWATER
We did not encounter groundwater or seepage during our recent or previous site investigations.
However, it is not uncommon for shallow seepage conditions to develop where none previously
existed when sites are irrigated or infiltration is implemented. Seepage is dependent on seasonal
precipitation, irrigation, land use, among other factors, and varies as a result. Proper surface drainage
will be important to future performance of the project. We expect the groundwater elevation at the site
to be between 80 and 90 feet MSL. We do not anticipate encountering groundwater during
construction of the proposed development.
5. GEOLOGIC HAZARDS
5.1 Faulting and Seismicity
A review of the referenced geologic materials and our knowledge of the general area indicates that the
site is not underlain by active, potentially active, or inactive faults. An active fault is defined by the
California Geological Survey (CGS) as a fault showing evidence for activity within the last
11,700 years. The site is not located within a State of California Earthquake Fault Zone.
The United States Geological Survey (USGS) has developed a program to evaluate the approximate
location of faulting. The following figure shows the location of the existing faulting in the San Diego
County and Southern California region. The faults are shown as solid, dashed and dotted traces
representing well-constrained, moderately constrained and inferred faults, respectively. The fault line
colors represent faults with ages less than 150 years (red), 15,000 years (orange), 130,000 years
(green), 750,000 years (blue) and 1.6 million years (black).
Project No. 07516-42-02 - 5 - September 18, 2020
Faults in the San Diego Area
The San Diego County and Southern California region is seismically active. The following figure
presents the occurrence of earthquakes with a magnitude greater than 2.5 from the period of 1900
through 2015 according to the Bay Area Earthquake Alliance website.
Project No. 07516-42-02 - 6 - September 18, 2020
Earthquakes in Southern California
Considerations important in seismic design include the frequency and duration of motion and the soil
conditions underlying the site. Seismic design of structures should be evaluated in accordance with the
California Building Code (CBC) guidelines currently adopted by the local agency.
5.2 Ground Rupture
The risk associated with ground rupture hazard is very low due to the absence of active faults at the
subject site.
5.3 Tsunamis and Seiches
The site is not located near the ocean or downstream of any large bodies of standing water. Therefore,
the risk of tsunamis or seiches associated with the site is low.
5.4 Flooding
According to maps produced by the Federal Emergency Management Agency (FEMA), the majority
of the site is zoned as “Zone X – Minimal Flood Hazard.” However, the limits of the 100- and 500-
year flood zones are on or immediately adjacent to the north property boundary. Based on our review
of FEMA flood maps, the risk of site flooding from channel overflow of the Otay River is low.
Project No. 07516-42-02 - 7 - September 18, 2020
5.5 Liquefaction and Seismically Induced Settlement
Soil liquefaction occurs within relatively loose, cohesionless sand located below the water table that is
subjected to ground accelerations from earthquakes. Due to the dense nature of the soils underlying the
site, proposed grading, and the lack of permanent, shallow groundwater, there is a low risk of
liquefaction occurring at the site.
5.6 Landslides
Based on our review of published geologic maps for the site vicinity, landslides are not mapped on the
property or at a location that could impact the site. Based on our review of historical aerial
photographs, landslide-related features are not discernable in the north-facing slope located near the
south property boundary. However, landslides have been mapped east of the site in the Otay
Formation, which overlies the Mission Valley Formation on the upthrown side of the La Nacion Fault
zone.
Bedding attitudes recorded during downhole logging of boring LD-1 are similar to those recorded in
areas surrounding the site. Steeper westerly dips ranging between 10 and 20 degrees were observed in
the boring, compared to three to five degrees west shown on local geologic maps. Steeper dips are
attributed to localized deformation resulting from movement on the La Nacion fault zone. The
proposed cut slope shown on the site plan is oriented perpendicular to strike, therefore no significant
out-of-slope dip component is anticipated. However, given the proximity of other landslides, we
recommend cut slope mapping during grading.
5.7 Geologic Hazard Category
Review of the 2008 City of San Diego Seismic Safety Study, Geologic Hazards and Faults, Sheet 6,
indicates the site is mapped as Geologic Hazard Categories 22 and 52. Category 22 is described as-
Landslides – possible or conjectured. Category 52 is described as-Other Terrain, other level areas,
gently sloping to steep terrain, favorable geologic structure, low risk.
Project No. 07516-42-02 - 8 - September 18, 2020
6. CONCLUSIONS AND RECOMMENDATIONS
6.1 General
6.1.1 No soil or geologic conditions were observed that would preclude the development of the
property as presently proposed provided that the recommendations of this report are
followed.
6.1.2 The site is underlain by compressible surficial deposits consisting of undocumented fill,
topsoil, colluvium, alluvium that generally range from 2 to 9 feet thick, but exceeds 18 feet
thick in the northwest portion of the site. The surficial soils will require complete removal
and recompaction.
6.1.3 Terrace deposits underlie the surficial deposits in the flatter areas of the site. The Tertiary-
aged Mission Valley Formation is exposed in the north facing slope adjacent to the south
property boundary. Terrace Deposits and the Mission Valley Formation are suitable for
support of the planned project.
6.1.4 With the exception of possible strong seismic shaking, no significant geologic hazards were
observed or are known to exist on the site that would adversely affect the site. No special
seismic design considerations, other than those recommended herein, are required.
6.1.5 Groundwater was not encountered during our investigation. However, groundwater may be
encountered during remedial grading on the north side of the property adjacent to the Otay
River channel.
6.1.6 Based on our experience and prior laboratory testing, we expect the majority of on-site soils
to possess a very low to medium expansion potential. We also expect the soils to have
negligible sulfate exposure to concrete structures.
6.1.7 Cut slopes should be observed and mapped during grading by an engineering geologist to
verify that the soil and geologic conditions do not differ significantly from those anticipated.
6.1.8 Provided the recommendations of this report are followed, it is our opinion that the
proposed development will not destabilize or result in settlement of adjacent properties and
City right-of-way.
Project No. 07516-42-02 - 9 - September 18, 2020
6.2 Soil and Excavation Characteristics
6.2.1 In general, special shoring requirements may not be necessary if temporary excavations will
be less than 4 feet in height. It is the responsibility of the contractor and their competent
person to ensure all excavations, temporary slopes and trenches are properly constructed and
maintained in accordance with applicable OSHA guidelines, in order to maintain safety and
the stability of the excavations and adjacent improvements. These excavations should not be
allowed to become saturated or to dry out. Surcharge loads should not be permitted to a
distance equal to the height of the excavation from the top of the excavation. The top of the
excavation should be a minimum of 15 feet from the edge of existing improvements.
Excavations steeper than those recommended or closer than 15 feet from an existing surface
improvement should be shored in accordance with applicable OSHA codes and regulations.
6.2.2 Excavation of existing undocumented fill and surficial deposits should be possible with
moderate to heavy effort using conventional heavy-duty equipment. Excavation of the
Mission Valley Formation may require very heavy effort with conventional heavy-duty
grading equipment.
6.2.3 The soil encountered during our field investigations is considered to be both “non-
expansive” (expansion index [EI] of 20 or less) and “expansive” (EI greater than 20) as
defined by 2019 California Building Code (CBC) Section 1803.5.3. Table 6.2.1 presents soil
classifications based on the expansion index. Based on prior laboratory test results, the
majority of the soil encountered is expected to possess a “very low” to “medium” expansion
potential. Samples of near pad grade soils should be collected after the completion of
grading to evaluate expansion index.
TABLE 6.2.1
EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX
Expansion Index (EI) Expansion Classification 2019 CBC
Expansion Classification
0 – 20 Very Low Non-Expansive
21 – 50 Low
Expansive 51 – 90 Medium
91 – 130 High
Greater Than 130 Very High
6.2.4 Results from prior laboratory testing indicate the on-site soils possess an “S0” sulfate
exposure class to concrete structures as defined by 2019 CBC Section 1904 and ACI 318-08
Sections 4.2 and 4.3. Table 6.2.2 presents a summary of concrete requirements set forth by
Project No. 07516-42-02 - 10 - September 18, 2020
2019 CBC Section 1904 and ACI 318. The presence of water-soluble sulfates is not a
visually discernible characteristic; therefore, other soil samples from the site could yield
different concentrations. Additionally, over time landscaping activities (i.e., addition of
fertilizers and other soil nutrients) may affect the concentration. Samples of near pad grade
soils should be collected to evaluate water-soluble sulfates after the completion of grading.
TABLE 6.2.2
REQUIREMENTS FOR CONCRETE EXPOSED TO
SULFATE-CONTAINING SOLUTIONS
Exposure Class
Water-Soluble
Sulfate Percent
by Weight
Cement
Type
Maximum
Water to
Cement Ratio
by Weight
Minimum
Compressive
Strength (psi)
S0 0.00-0.10 -- -- 2,500
S1 0.10-0.20 II 0.50 4,000
S2 0.20-2.00 V 0.45 4,500
S3 > 2.00 V+Pozzolan or Slag 0.45 4,500
6.2.5 Geocon Incorporated does not practice in the field of corrosion engineering; therefore,
further evaluation by a corrosion engineer may be needed to incorporate the necessary
precautions to avoid premature corrosion of underground pipes and buried metal in direct
contact with soil.
6.3 Grading Recommendations
6.3.1 All grading should be performed in accordance with the Recommended Grading
Specifications contained in Appendix D. Where the recommendations of this section conflict
with those of Appendix D, the recommendations of this section take precedence. All
earthwork should be observed and all fill tested for proper compaction by Geocon
Incorporated.
6.3.2 Prior to commencing grading, a preconstruction conference should be held at the site with
the owner or developer, grading contractor, civil engineer, City of Chula Vista
representatives, and geotechnical engineer in attendance. Special soil handling and/or the
grading plans can be discussed at that time.
6.3.3 Site preparation should begin with the removal of deleterious material, debris, and
vegetation. The depth of vegetation removal should be such that material exposed in cut
areas or soil to be used as fill is relatively free of organic matter. Material generated during
Project No. 07516-42-02 - 11 - September 18, 2020
stripping and/or site demolition should be exported from the site. Asphalt and concrete
should not be mixed with the fill soil unless approved by the Geotechnical Engineer.
6.3.4 Abandoned foundations and buried utilities (if encountered) should be removed and the
resultant depressions and/or trenches backfilled with properly compacted soil as part of the
remedial grading.
6.3.5 All compressible soil deposits including undocumented fill, stockpiles, alluvium and
colluvium within areas where structural improvements and/or structural fills are planned,
should be removed to expose the underlying Terrace Deposits or Mission Valley Formation,
prior to placing additional fill and/or structural loads. The actual extent of unsuitable soil
removals will be evaluated in the field during grading by the geotechnical engineer and/or
engineering geologist.
6.3.6 Based on the current grading plan, cut to fill transitions are expected within some of the lots.
Lots with cut-fill transitions should be undercut at least 3 feet and replaced with properly
compacted fill. The undercut should be sloped at a minimum of 1 percent toward the street
or deeper fill area.
6.3.7 Removal of compressible surficial soils should extend beyond the toe of fill slopes a
horizontal distance equal to the depth of the remedial removal (see Figure 5 for general
information). The actual extent of remedial grading should be determined in the field by the
geotechnical engineer or engineering geologist.
6.3.8 Prior to placing fill, the base of excavations and surface of previously placed fill and
compacted fill should be scarified; moisture conditioned as necessary and compacted. Fill
soils may then be placed and compacted in layers to the design finish grade elevations. In
general, on-site soils are suitable for re-use as fill if free from vegetation, debris and other
deleterious material. Layers of fill should be no thicker than will allow for adequate bonding
and compaction. All fill, including scarified ground surfaces and backfill, should be
compacted to at least 90 percent of laboratory maximum dry density as determined by
ASTM D 1557 at or slightly above optimum moisture content. Overly wet materials will
require drying and/or mixing with drier soils to facilitate proper compaction.
6.3.9 The upper 3 feet of fill on all lots and streets should be composed of properly compacted
very low to low expansive soils. Highly expansive soils, if encountered, should be placed in
deeper fill areas and properly compacted. Very low to low expansive soils are defined as
those soils that have an Expansion Index of 50 or less. Boulders, concretions, concrete
chunks greater than 12 inches in maximum dimension should not be placed within 5 feet of
Project No. 07516-42-02 - 12 - September 18, 2020
finish grade or 3 feet from the deepest utility within streets. Specific recommendations for
the placement of oversize rock is contained in the Grading Specifications contained in
Appendix D.
6.3.10 Imported fill (if necessary) should consist of granular materials with a very low to low
expansion potential (EI of 50 or less), be free of deleterious material or stones larger than
3 inches, and should be compacted as recommended herein. Geocon Incorporated should be
notified of the import soil source and should be authorized to perform laboratory testing of
import soil prior to its arrival at the site to evaluate its suitability as fill material.
6.4 Slopes
6.4.1 Slope stability analyses were performed for proposed cut slopes up to 55 feet high (2:1
gradient), the existing hillside slope (2.5:1 or flatter) that has a height up to approximately
120 feet and extends onto the property to the south, and proposed fill slopes up to 10 feet in
height (2:1 gradient). The stability analyses were performed using simplified Janbu analysis.
Our analyses utilized average drained direct shear strength parameters based on laboratory
tests performed for this project and our experience with similar soils. The analyses indicate
planned cut and fill slopes, and the existing native perimeter slope will have a calculated
factors of safety in excess of 1.5 under static conditions for both deep-seated failure and
shallow sloughing conditions. A summary of slope stability analyses is presented on
Figures 6 through 9.
6.4.2 All cut slope excavations should be observed during grading by an engineering geologist to
verify that soil and geologic conditions do not differ significantly from those anticipated.
6.4.3 The outer 15 feet (or a distance equal to the height of the slope, whichever is less) of fill
slopes should be composed of properly compacted granular soil fill to reduce the potential
for surficial sloughing. Granular “soil” fill is defined as a well-graded soil mix with less
than 20 percent fines (silt and clay particles). Poorly graded soils with less than 5 percent
fines should not be used in the slope zone due to high erosion potential. All slopes should be
compacted by backrolling with a loaded sheepsfoot roller at vertical intervals not to exceed
4 feet and should be track-walked at the completion of each slope such that the fill soils are
uniformly compacted to at least 90 percent relative compaction to the face of the finished
sloped.
6.4.4 All slopes should be landscaped with drought-tolerant vegetation, having variable root
depths and requiring minimal landscape irrigation. In addition, all slopes should be drained
and properly maintained to reduce erosion.
Project No. 07516-42-02 - 13 - September 18, 2020
6.5 Seismic Design Criteria (2019)
6.5.1 Table 6.5.1 summarizes site-specific design criteria obtained from the 2019 California
Building Code (CBC; Based on the 2018 International Building Code [IBC] and ASCE 7-
16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. We used the computer
program U.S. Seismic Design Maps, provided by the Structural Engineers Association of
California (SEAOC) to calculate the seismic design parameters. The short spectral response
uses a period of 0.2 second. We evaluated the Site Class based on the discussion in
Section 1613.2.2 of the 2019 CBC and Table 20.3-1 of ASCE 7-16. Site Class C can be
used for lots with fill thickness of 20 feet or less. Site Class D is applicable to lots with fill
thicknesses greater than 20 feet. The majority of the site falls within Site Class C. A couple
lots in the northwest corner might fall into Site Class D after completion of remedial
grading. The values presented herein are for the risk-targeted maximum considered
earthquake (MCER). Sites designated as Site Class D, E and F may require additional
analyses if requested by the project structural engineer and client.
TABLE 6.5.1
2019 CBC SEISMIC DESIGN PARAMETERS
Parameter Value 2019 CBC
Reference
Site Class C D Section 1613.2.2
MCER Ground Motion Spectral Response
Acceleration – Class B (short), SS 0.901g 0.901g Figure 1613.2.1(1)
MCER Ground Motion Spectral Response
Acceleration – Class B (1 sec), S1 0.315g 0.315g Figure 1613.2.1(2)
Site Coefficient, FA 1.2 1.14 Table 1613.2.3(1)
Site Coefficient, FV 1.5 1.985* Table 1613.2.3(2)
Site Class Modified MCER Spectral Response
Acceleration (short), SMS 1.081g 1.027g Section 1613.2.3
(Eqn 16-36)
Site Class Modified MCER Spectral Response
Acceleration – (1 sec), SM1 0.472g 0.625g* Section 1613.2.3
(Eqn 16-37)
5% Damped Design Spectral Response
Acceleration (short), SDS 0.721g 0.684g Section 1613.2.4
(Eqn 16-38)
5% Damped Design Spectral Response
Acceleration (1 sec), SD1 0.315g 0.417g* Section 1613.2.4
(Eqn 16-39)
* Using the code-based values presented in this table, in lieu of a performing a ground motion hazard
analysis, requires the exceptions outlined in ASCE 7-16 Section 11.4.8 be followed by the project
structural engineer. Per Section 11.4.8 of ASCE/SEI 7-16, a ground motion hazard analysis should
be performed for projects for Site Class “E” sites with Ss greater than or equal to 1.0g and for Site
Class “D” and “E” sites with S1 greater than 0.2g. Section 11.4.8 also provides exceptions which
indicates that the ground motion hazard analysis may be waived provided the exceptions are
followed.
Project No. 07516-42-02 - 14 - September 18, 2020
6.5.2 Table 6.5.2 presents the mapped maximum considered geometric mean (MCEG) seismic
design parameters for projects located in Seismic Design Categories of D through F in
accordance with ASCE 7-16.
TABLE 6.5.2
ASCE 7-16 PEAK GROUND ACCELERATION
Parameter Value ASCE 7-16 Reference
Site Class C D
Mapped MCEG Peak Ground
Acceleration, PGA 0.396 0.396 Figure 22-7
Site Coefficient, FPGA 1.2 1.204 Table 11.8-1
Site Class Modified MCEG Peak
Ground Acceleration, PGAM
0.475 0.477g Section 11.8.3 (Eqn 11.8-1)
6.5.3 Conformance to the criteria in Tables 6.5.1 and 6.5.2 for seismic design does not constitute
any kind of guarantee or assurance that significant structural damage or ground failure will
not occur if a large earthquake occurs. The primary goal of seismic design is to protect life,
not to avoid all damage, since such design may be economically prohibitive.
6.5.4 The project structural engineer and architect should evaluate the appropriate Risk Category
and Seismic Design Category for the planned structures. The values presented herein
assume a Risk Category of II and resulting in a Seismic Design Category D. Table 6.5.3
presents a summary of the risk categories.
TABLE 6.5.3
ASCE 7-16 RISK CATEGORIES
Risk Category Building Use Examples
I Low risk to Human Life at Failure Barn, Storage Shelter
II
Nominal Risk to Human Life at
Failure (Buildings Not Designated
as I, III or IV)
Residential, Commercial and Industrial
Buildings
III Substantial Risk to Human Life
at Failure
Theaters, Lecture Halls, Dining Halls,
Schools, Prisons, Small Healthcare
Facilities, Infrastructure Plants, Storage
for Explosives/Toxins
IV Essential Facilities
Hazardous Material Facilities,
Hospitals, Fire and Rescue, Emergency
Shelters, Police Stations, Power
Stations, Aviation Control Facilities,
National Defense, Water Storage
Project No. 07516-42-02 - 15 - September 18, 2020
6.6 Foundations
6.6.1 The following foundation recommendations apply to one- to three story structures and are
based on the building pads being underlain by properly compacted fill or native soils, and
soil within 3 feet of finish grade consisting of very low to medium expansive soils
(Expansion Index of 90 or less). The foundation recommendations have been separated into
three categories dependent on the thickness and geometry of the underlying fill soils as well
as the expansion index of the prevailing subgrade soils of a particular building pad (or lot).
The foundation category criteria are presented in Table 6.6.1
TABLE 6.6.1
FOUNDATION CATEGORY CRITERIA
Foundation
Category
Maximum Fill
Thickness, T (feet)
Differential Fill
Thickness, D (feet)
Expansion
Index (EI)
I T<20 -- EI<50
II 20<T<50 10<D<20 50<EI<90
III T>50 D>20 90<EI<130
6.6.2 We will provide final foundation categories for each building or lot after completion of
grading (finish pad grades have been achieved) and laboratory expansion testing of the
finish grade soils is complete.
6.6.3 The proposed structures can be supported on a shallow foundation system founded in the
compacted fill/formational materials. Foundations for the structure should consist of
continuous strip footings and/or isolated spread footings. Table 6.6.2 presents minimum
foundation and interior concrete slab design criteria for conventional foundation systems.
TABLE 6.6.2
CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY
Foundation
Category
Minimum Footing
Embedment
Depth (inches)
Continuous Footing
Reinforcement
Interior Slab
Reinforcement
I 12 Two No. 4 bars,
one top and one bottom
6 x 6 - 10/10 welded wire
mesh at slab mid-point
II 18 Four No. 4 bars,
two top and two bottom
No. 3 bars at 24 inches
on center, both directions
III 24 Four No. 5 bars,
two top and two bottom
No. 3 bars at 18 inches
on center, both directions
Project No. 07516-42-02 - 16 - September 18, 2020
6.6.4 Table 6.6.3 provides a summary of the foundation design recommendations.
TABLE 6.6.3
SUMMARY OF FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Continuous Foundation Width 12 inches
Minimum Isolated Foundation Width 24 inches
Minimum Foundation Depth See Table 6.6.2
Minimum Steel Reinforcement See Table 6.6.2
Allowable Bearing Capacity 2,000 psf
Bearing Capacity Increase 500 psf per additional foot of footing depth
300 psf per additional foot of footing width
Maximum Allowable Bearing Capacity 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
Footing Size Used for Settlement 9-Foot Square
Design Expansion Index 50 or less
6.6.5 The foundations should be embedded in accordance with the recommendations herein and
the Wall/Column Footing Dimension Detail below. The embedment depths should be
measured from the lowest adjacent pad grade for both interior and exterior footings.
Footings should be deepened such that the bottom outside edge of the footing is at
least 7 feet horizontally from the face of the slope (unless designed with a post-tensioned
foundation system as discussed herein).
Wall/Column Footing Dimension Detail
6.6.6 The bearing capacity values presented herein are for dead plus live loads and may be
increased by one-third when considering transient loads due to wind or seismic forces.
Project No. 07516-42-02 - 17 - September 18, 2020
6.6.7 Under the recommended allowable bearing pressures provided, we expect settlement as a
result of building loading to be less than 1-inch total and ½-inch differential over a span of
40 feet.
6.6.8 Conventional building concrete slabs-on-grade should be at least 4 inches thick for
Foundation Categories I and II and 5 inches thick for Foundation Category III.
6.6.9 A vapor retarder should underlie slabs that may receive moisture-sensitive floor coverings
or may be used to store moisture-sensitive materials. The vapor retarder design should be
consistent with the guidelines presented in the American Concrete Institute’s (ACI) Guide
for Concrete Slabs that Receive Moisture-Sensitive Flooring Materials (ACI 302.2R-06). In
addition, the membrane should be installed in accordance with manufacturer’s
recommendations and ASTM requirements and in a manner that prevents puncture. The
project architect or developer should specify the type of vapor retarder used based on the
type of floor covering that will be installed and if the structure will possess a humidity
controlled environment.
6.6.10 The project foundation engineer, architect, and/or developer should determine the thickness
of bedding sand below the slab. However, Geocon should be contacted to provide
recommendations if the bedding sand is thicker than 6 inches.
6.6.11 The foundation design engineer should provide appropriate concrete mix design criteria and
curing measures to assure proper curing of the slab by reducing the potential for rapid
moisture loss and subsequent cracking and/or slab curl. We suggest that the foundation
design engineer present the concrete mix design and proper curing methods on the
foundation plans. It is critical that the foundation contractor understands and follows the
specifications presented on the foundation plans.
6.6.12 As an alternative to the conventional foundation recommendations, consideration should be
given to the use of post-tensioned concrete slab and foundation systems for the support of
the proposed structures. The post-tensioned systems should be designed by a structural
engineer experienced in post-tensioned slab design and design criteria of the Post-
Tensioning Institute (PTI) DC10.5 Standard Requirements for Design and Analysis of
Shallow Post-Tensioned Concrete Foundations on Expansive Soils or WRI/CRSI Design of
Slab-on-Ground Foundations, as required by the 2019 California Building Code (CBC
Section 1808.6.2). Although this procedure was developed for expansive soil conditions, we
understand it can also be used to reduce the potential for foundation distress due to
differential fill settlement. The post-tensioned design should incorporate the geotechnical
Project No. 07516-42-02 - 18 - September 18, 2020
parameters presented on Table 6.6.4. The parameters presented in Table 6.6.4 are based on
the guidelines presented in the PTI, DC10.5 design manual.
TABLE 6.6.4
POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS
Post-Tensioning Institute (PTI),
Third Edition Design Parameters
Foundation Category
I II III
Thornthwaite Index -20 -20 -20
Equilibrium Suction 3.9 3.9 3.9
Edge Lift Moisture Variation Distance, eM (feet) 5.3 5.1 4.9
Edge Lift, yM (inches) 0.61 1.10 1.58
Center Lift Moisture Variation Distance, eM (feet) 9.0 9.0 9.0
Center Lift, yM (inches) 0.30 0.47 0.66
6.6.13 The foundations for the post-tensioned slabs should be embedded in accordance with the
recommendations of the structural engineer. For moisture cut-off, we recommend the
perimeter foundation have an embedment depth of at least 12 inches. If a post-tensioned mat
foundation system is planned, the slab should possess a thickened edge with a minimum
width of 12 inches that extends at least 12 inches below the clean sand layer.
6.6.14 If the structural engineer proposes a post-tensioned foundation design method other than
PTI, DC 10.5:
The deflection criteria presented in Table 6.6.4 are still applicable.
Interior stiffener beams should be used for Foundation Categories II and III.
The width of the perimeter foundations should be at least 12 inches.
The perimeter footing embedment depths should be at least 12 inches, 18 inches and
24 inches for foundation categories I, II, and III, respectively. The embedment
depths should be measured from the lowest adjacent pad grade.
6.6.15 Foundation systems for the lots that possess a foundation Category I and a “very low”
expansion potential (expansion index of 20 or less) can be designed using the method
described in Section 1808 of the 2019 CBC. If post-tensioned foundations are planned, an
alternative, commonly accepted design method (other than PTI) can be used. However, the
post-tensioned foundation system should be designed with a total and differential deflection
of 1 inch. Geocon Incorporated should be contacted to review the plans and provide
additional information, if necessary.
Project No. 07516-42-02 - 19 - September 18, 2020
6.6.16 If an alternate design method is contemplated, Geocon Incorporated should be contacted to
evaluate if additional expansion index testing should be performed to identify the lots that
possess a “very low” expansion potential (expansion index of 20 or less).
6.6.17 Our experience indicates post-tensioned slabs are susceptible to excessive edge lift,
regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the
perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI
design procedures primarily address the potential center lift of slabs but, because of the
placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after
tensioning reduces the ability of the system to mitigate edge lift. The structural engineer
should design the foundation system to reduce the potential of edge lift occurring for the
proposed structures.
6.6.18 During the construction of the post-tension foundation system, the concrete should be
placed monolithically. Under no circumstances should cold joints form between the
footings/grade beams and the slab during the construction of the post-tension foundation
system unless designed by the project structural engineer.
6.6.19 Isolated footings outside of the slab area, if present, should have the minimum embedment
depth and width recommended for conventional foundations for a particular Foundation
Category. The use of isolated footings, which are located beyond the perimeter of the
building and support structural elements connected to the building, are not recommended for
Category III. Where this condition cannot be avoided, the isolated footings should be
connected to the building foundation system with grade beams. In addition, consideration
should be given to connecting patio slabs, which exceed 5 feet in width, to the building
foundation to reduce the potential for future separation to occur.
6.6.20 Interior stiffening beams should be incorporated into the design of the foundation system in
accordance with the PTI design procedures.
6.6.21 Special subgrade presaturation is not deemed necessary prior to placing concrete; however,
the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary,
to maintain a moist condition as would be expected in any such concrete placement.
6.6.22 Where buildings or other improvements are planned near the top of a slope steeper than 3:1
(horizontal:vertical), special foundations and/or design considerations are recommended due
to the tendency for lateral soil movement to occur.
Project No. 07516-42-02 - 20 - September 18, 2020
For fill slopes less than 20 feet high or cut slopes regardless of height, footings
should be deepened such that the bottom outside edge of the footing is at least 7 feet
horizontally from the face of the slope.
For fill slopes greater than 20 feet high, foundations should be extended to a depth
where the minimum horizontal distance is equal to H/3 (where H equals the vertical
distance from the top of the fill slope to the base of the fill soil) with a minimum of
7 feet but need not exceed 40 feet. The horizontal distance is measured from the
outer, deepest edge of the footing to the face of the slope. A post-tensioned slab and
foundation system or mat foundation system can be used to help reduce potential
foundation distress associated with slope creep and lateral fill extension. Specific
design parameters or recommendations for either of these alternatives can be
provided once the building location and fill slope geometry have been determined.
If swimming pools are planned, Geocon Incorporated should be contacted for a
review of specific site conditions.
Swimming pools located within 7 feet of the top of cut or fill slopes are not
recommended. Where such a condition cannot be avoided, the portion of the
swimming pool wall within 7 feet of the slope face be designed assuming that the
adjacent soil provides no lateral support. This recommendation applies to fill slopes
up to 30 feet in height, and cut slopes regardless of height. For swimming pools
located near the top of fill slopes greater than 30 feet in height, additional
recommendations may be required and Geocon Incorporated should be contacted
for a review of specific site conditions.
Although other improvements that are relatively rigid or brittle, such as concrete
flatwork or masonry walls, may experience some distress if located near the top of a
slope, it is generally not economical to mitigate this potential. It may be possible,
however, to incorporate design measures that would permit some lateral soil
movement without causing extensive distress. Geocon Incorporated should be
consulted for specific recommendations.
6.6.23 The recommendations of this report are intended to reduce the potential for cracking of slabs
due to expansive soil (if present), differential settlement of existing soil or soil with varying
thicknesses. However, even with the incorporation of the recommendations presented
herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still
exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete
shrinkage cracks is independent of the supporting soil characteristics. The occurrence may
be reduced and/or controlled by: limiting the slump of the concrete, proper concrete
placement and curing, and by the placement of crack control joints at periodic intervals, in
particular, where re-entrant slab corners occur.
6.6.24 Geocon Incorporated should be consulted to provide additional design parameters as
required by the structural engineer.
Project No. 07516-42-02 - 21 - September 18, 2020
6.7 Conventional Retaining Wall Recommendations
6.7.1 Retaining walls should be designed using the values presented in Table 6.7.1. Soil with an
expansion index (EI) of greater than 50 should not be used as backfill material behind
retaining walls.
TABLE 6.7.1
RETAINING WALL DESIGN RECOMMENDATIONS
Parameter
Value
EI<50 EI<90
Active Soil Pressure, A (Fluid Density, Level Backfill) 35 pcf 40 pcf
Active Soil Pressure, A (Fluid Density, 2:1 Sloping Backfill) 45 psf 55 pcf
Seismic Pressure, S 15H psf
At-Rest/Restrained Walls Additional Uniform Pressure (0 to 8 Feet High) 7H psf
At-Rest/Restrained Walls Additional Uniform Pressure (8+ Feet High) 13H psf
Expected Expansion Index for the Subject Property EI<50
H equals the height of the retaining portion of the wall
6.7.2 The project retaining walls should be designed as shown in the Retaining Wall Loading
Diagram.
Retaining Wall Loading Diagram
Project No. 07516-42-02 - 22 - September 18, 2020
6.7.3 Unrestrained walls are those that are allowed to rotate more than 0.001H (where H equals
the height of the retaining portion of the wall) at the top of the wall. Where walls are
restrained from movement at the top (at-rest condition), an additional uniform pressure of
7H psf should be added to the active soil pressure for walls 8 feet or less. For walls greater
than 8 feet tall, an additional uniform pressure of 13H psf should be applied to the wall
starting at 8 feet from the top of the wall to the base of the wall. For retaining walls subject
to vehicular loads within a horizontal distance equal to two-thirds the wall height, a
surcharge equivalent to 2 feet of fill soil should be added.
6.7.4 The structural engineer should determine the Seismic Design Category for the project in
accordance with Section 1613.2.5 of the 2019 CBC or Section 11.6 of ASCE 7-16. For
structures assigned to Seismic Design Category of D, E, or F, retaining walls that support
more than 6 feet of backfill should be designed with seismic lateral pressure in accordance
with Section 1803.5.12 of the 2019 CBC. The seismic load is dependent on the retained
height where H is the height of the wall, in feet, and the calculated loads result in pounds per
square foot (psf) exerted at the base of the wall and zero at the top of the wall. A seismic
load of 17H psf should be used for design. We used the peak ground acceleration adjusted
for Site Class effects, PGAM, of 0.477g calculated from ASCE 7-16 Section 11.8.3 and
applied a pseudo-static coefficient of 0.3.
6.7.5 Retaining walls should be designed to ensure stability against overturning sliding, and
excessive foundation pressure. Where a keyway is extended below the wall base with the
intent to engage passive pressure and enhance sliding stability, it is not necessary to
consider active pressure on the keyway.
6.7.6 Drainage openings through the base of the wall (weep holes) should not be used where the
seepage could be a nuisance or otherwise adversely affect the property adjacent to the base
of the wall. The recommendations herein assume a properly compacted granular (EI of 50 or
less) free-draining backfill material with no hydrostatic forces or imposed surcharge load.
The retaining wall should be properly drained as shown in the Typical Retaining Wall
Drainage Detail. If conditions different than those described are expected, or if specific
drainage details are desired, Geocon Incorporated should be contacted for additional
recommendations.
Project No. 07516-42-02 - 23 - September 18, 2020
Typical Retaining Wall Drainage Detail
6.7.7 The retaining walls may be designed using either the active and restrained (at-rest) loading
condition or the active and seismic loading condition as suggested by the structural
engineer. Typically, it appears the design of the restrained condition for retaining wall
loading may be adequate for the seismic design of the retaining walls. However, the active
earth pressure combined with the seismic design load should be reviewed and also
considered in the design of the retaining walls.
6.7.8 In general, wall foundations having should be designed in accordance with Table 6.7.2. The
proximity of the foundation to the top of a slope steeper than 3:1 could impact the allowable
soil bearing pressure. Therefore, retaining wall foundations should be deepened such that
the bottom outside edge of the footing is at least 7 feet horizontally from the face of the
slope.
TABLE 6.7.2
SUMMARY OF RETAINING WALL FOUNDATION RECOMMENDATIONS
Parameter Value
Minimum Retaining Wall Foundation Width 12 inches
Minimum Retaining Wall Foundation Depth 12 Inches
Minimum Steel Reinforcement Per Structural Engineer
Bearing Capacity 2,000 psf
Bearing Capacity Increase 500 psf per additional foot of footing depth
300 psf per additional foot of footing width
Maximum Bearing Capacity 4,000 psf
Estimated Total Settlement 1 Inch
Estimated Differential Settlement ½ Inch in 40 Feet
Project No. 07516-42-02 - 24 - September 18, 2020
6.7.9 The recommendations presented herein are generally applicable to the design of rigid
concrete or masonry retaining walls. In the event that other types of walls (such as
mechanically stabilized earth [MSE] walls, soil nail walls, or soldier pile walls) are planned,
Geocon Incorporated should be consulted for additional recommendations.
6.7.10 Unrestrained walls will move laterally when backfilled and loading is applied. The amount
of lateral deflection is dependent on the wall height, the type of soil used for backfill, and
loads acting on the wall. The retaining walls and improvements above the retaining walls
should be designed to incorporate an appropriate amount of lateral deflection as determined
by the structural engineer.
6.7.11 Soil contemplated for use as retaining wall backfill, including import materials, should be
identified in the field prior to backfill. At that time, Geocon Incorporated should obtain
samples for laboratory testing to evaluate its suitability. Modified lateral earth pressures
may be necessary if the backfill soil does not meet the required expansion index or shear
strength. City or regional standard wall designs, if used, are based on a specific active lateral
earth pressure and/or soil friction angle. In this regard, on-site soil to be used as backfill may
or may not meet the values for standard wall designs. Geocon Incorporated should be
consulted to assess the suitability of the on-site soil for use as wall backfill if standard wall
designs will be used.
6.8 Lateral Loading
6.8.1 Table 6.8 should be used to help design the proposed structures and improvements to resist
lateral loads for the design of footings or shear keys. The allowable passive pressure
assumes a horizontal surface extending at least 5 feet, or three times the surface generating
the passive pressure, whichever is greater. The upper 12 inches of material in areas not
protected by floor slabs or pavement should not be included in design for passive resistance.
Where walls are planned adjacent to and/or on descending slopes, a passive pressure of
150 pcf should be used in design.
TABLE 6.8
SUMMARY OF LATERAL LOAD DESIGN RECOMMENDATIONS
Parameter Value
Passive Pressure Fluid Density 300 pcf
Passive Pressure Fluid Density Adjacent to and/or on Descending Slopes 150 pcf
Coefficient of Friction (Concrete and Soil) 0.35
Coefficient of Friction (Along Vapor Barrier) 0.2 to 0.25*
* Per manufacturer’s recommendations.
Project No. 07516-42-02 - 25 - September 18, 2020
6.8.2 The passive and frictional resistant loads can be combined for design purposes. The lateral
passive pressures may be increased by one-third when considering transient loads due to
wind or seismic forces.
6.9 Preliminary Pavement Recommendations
6.9.1 Preliminary pavement recommendations for the streets and parking areas are provided
below. The final pavement sections should be based on the R-Value of the subgrade soil
encountered at final subgrade elevation. For pavement design we used a laboratory R-Value
of 10. Preliminary flexible pavement sections are presented in 6.9.1. We calculated the
flexible pavement sections in general conformance with the Caltrans Method of Flexible
Pavement Design (Highway Design Manual, Section 608.4) using estimated Traffic Indices
(TI) in general accordance with City of Chula Vista guidelines (the City requires that private
streets be designed in general accordance with City standards). The project civil engineer or
traffic engineer should determine the appropriate Traffic Index (TI) or traffic loading
expected on the project for the various pavement areas that will be constructed.
TABLE 6.9.1
PRELIMINARY ASPHALT CONCRETE PAVEMENT SECTIONS
Location Minimum
Traffic Index
Assumed
Subgrade
R-Value
Asphalt
Concrete
(inches)
Class 2
Aggregate
Base (inches)
Residential Cul-De-Sac 5.0 10 3 9
Residential 6.0 10 3 12.5
6.9.2 Asphalt concrete should conform to Section 203-6 of the Standard Specifications for Public
Works Construction (Green Book). Cement treated base should conform to Greenbook
Section 301-3.3. Class 2 aggregate base materials should conform to Section 26-1.02B of
the Standard Specifications of the State of California, Department of Transportation
(Caltrans).
6.9.3 Prior to placing base material, the subgrade should be scarified, moisture conditioned and
recompacted to a minimum of 95 percent relative compaction. The depth of compaction
should be at least 12 inches. The base material should be compacted to at least 95 percent
relative compaction. Asphalt concrete should be compacted to a density of at least
95 percent of the laboratory Hveem density in accordance with ASTM D 2726.
6.9.4 A rigid Portland Cement concrete (PCC) pavement section should be placed in driveway
entrance aprons. The concrete pad for trash truck areas should be large enough such that the
Project No. 07516-42-02 - 26 - September 18, 2020
truck wheels will be positioned on the concrete during loading. We calculated the rigid
pavement section in general conformance with the procedure recommended by the
American Concrete Institute report ACI 330R-08 Guide for Design and Construction of
Concrete Parking Lots using the parameters presented in Table 6.9.2.
TABLE 6.9.2
PRELIMINARY RIGID PAVEMENT DESIGN PARAMETERS
Design Parameter Design Value
Modulus of subgrade reaction, k 50 pci
Modulus of rupture for concrete, MR 500 psi
Traffic Category, TC A-1 and B
Average daily truck traffic, ADTT 1 and 25
6.9.5 Based on the criteria presented herein, the PCC pavement sections should have a minimum
thickness as presented in Table 6.9.3.
TABLE 6.9.3
PRELIMINARY RIGID PAVEMENT RECOMMENDATIONS
Location Portland Cement Concrete (inches)
Automobile Areas (TC=A-1, ADDT = 1) 5.5
Heavy Truck and Fire Lane Areas (TC=C, ADDT = 100) 7.0
6.9.6 The PCC pavement should be placed over subgrade soil that is compacted to a dry density
of at least 95 percent of the laboratory maximum dry density near to slightly above optimum
moisture content. For single-family residential lot driveways, 90 percent of the laboratory
maximum dry density near to slightly above optimum moisture content is acceptable. This
pavement section is based on a minimum concrete compressive strength of approximately
3,200 psi (pounds per square inch).
6.9.7 A thickened edge or integral curb should be constructed on the outside of concrete slabs
subjected to wheel loads. The thickened edge should be 1.2 times the slab thickness or a
minimum thickness of 2 inches, whichever results in a thicker edge, at the slab edge and
taper back to the recommended slab thickness 3 feet behind the face of the slab (e.g., a
7-inch-thick slab would have a 9-inch-thick edge). Reinforcing steel will not be necessary
within the concrete for geotechnical purposes with the exception of loading docks, trash bin
enclosures, and dowels at construction joints as discussed below.
Project No. 07516-42-02 - 27 - September 18, 2020
6.9.8 To control the location and spread of concrete shrinkage cracks, crack-control joints
(weakened plane joints) should be included in the design of the concrete pavement slab.
Crack-control joints should not exceed 30 times the slab thickness with a maximum spacing
of 15 feet (e.g., a 7-inch-thick slab would have a 15-foot spacing pattern) and should be
sealed with an appropriate sealant to prevent the migration of water through the control joint
to the subgrade materials. The depth of the crack-control joints should be determined by the
referenced ACI report.
6.9.9 To provide load transfer between adjacent pavement slab sections, a trapezoidal-keyed
construction joint should be installed. As an alternative to the keyed joint, dowelling is
recommended between construction joints. As discussed in the referenced ACI guide,
dowels should consist of smooth, ⅞-inch-diameter reinforcing steel 14 inches long
embedded a minimum of 6 inches into the slab on either side of the construction joint.
Dowels should be located at the midpoint of the slab, spaced at 12 inches on center and
lubricated to allow joint movement while still transferring loads. The project structural
engineer may provide alternative recommendations for load transfer.
6.9.10 The performance of pavement is highly dependent on providing positive surface drainage
away from the edge of the pavement. Ponding of water on or adjacent to the pavement will
likely result in pavement distress and subgrade failure. Drainage from landscaped areas
should be directed to controlled drainage structures. Landscape areas adjacent to the edge of
asphalt pavements are not recommended due to the potential for surface or irrigation water
to infiltrate the underlying permeable aggregate base and cause distress. Where such a
condition cannot be avoided, consideration should be given to incorporating measures that
will significantly reduce the potential for subsurface water migration into the aggregate
base. If planter islands are planned, the perimeter curb should extend at least 6 inches below
the level of the base materials.
6.10 Exterior Concrete Flatwork
6.10.1 Exterior concrete flatwork not subject to vehicular traffic should be constructed in
accordance with the recommendations presented in Table 6.10. The recommended steel
reinforcement would help reduce the potential for cracking.
Project No. 07516-42-02 - 28 - September 18, 2020
TABLE 6.10
MINIMUM CONCRETE FLATWORK RECOMMENDATIONS
Expansion
Index, EI Minimum Steel Reinforcement* Options Minimum
Thickness
EI < 90 6x6-W2.9/W2.9 (6x6-6/6) welded wire mesh
4 Inches No. 3 Bars 18 inches on center, Both Directions
EI < 130 4x4-W4.0/W4.0 (4x4-4/4) welded wire mesh
No. 4 Bars 12 inches on center, Both Directions
* In excess of 8 feet square.
6.10.2 Even with the incorporation of the recommendations of this report, the exterior concrete
flatwork has a potential to experience some uplift due to expansive soil beneath grade. The
steel reinforcement should overlap continuously in flatwork to reduce the potential for
vertical offsets within flatwork. Additionally, flatwork should be structurally connected to
the curbs, where possible, to reduce the potential for offsets between the curbs and the
flatwork.
6.10.3 Concrete flatwork should be provided with crack control joints to reduce and/or control
shrinkage cracking. Crack control spacing should be determined by the project structural
engineer based upon the slab thickness and intended usage. Criteria of the American
Concrete Institute (ACI) should be taken into consideration when establishing crack control
spacing. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted
in accordance with criteria presented in the grading section prior to concrete placement.
Subgrade soil should be properly compacted, and the moisture content of subgrade soil
should be verified prior to placing concrete. Base materials will not be required below
concrete improvements.
6.10.4 The recommendations presented herein are intended to reduce the potential for cracking of
exterior slabs as a result of differential movement. However, even with the incorporation of
the recommendations presented herein, slabs-on-grade will still crack. The occurrence of
concrete shrinkage cracks is independent of the soil supporting characteristics. Their
occurrence may be reduced and/or controlled by limiting the slump of the concrete, the use
of crack control joints and proper concrete placement and curing. Crack control joints
should be spaced at intervals no greater than 12 feet. Literature provided by the Portland
Concrete Association (PCA) and American Concrete Institute (ACI) present
recommendations for proper concrete mix, construction, and curing practices, and should be
incorporated into project construction.
Project No. 07516-42-02 - 29 - September 18, 2020
6.11 Slope Maintenance
6.11.1 Slopes that are steeper than 3:1 (horizontal:vertical) may, under conditions which are both
difficult to prevent and predict, be susceptible to near surface (surficial) slope instability.
The instability is typically limited to the outer three feet of a portion of the slope and usually
does not directly impact the improvements on the pad areas above or below the slope. The
occurrence of surficial instability is more prevalent on fill slopes and is generally preceded
by a period of heavy rainfall, excessive irrigation, or the migration of subsurface seepage.
The disturbance and/or loosening of the surficial soils, as might result from root growth, soil
expansion, or excavation for irrigation lines and slope planting, may also be a significant
contributing factor to surficial instability. It is, therefore, recommended that, to the
maximum extent practical: (a) disturbed/loosened surficial soils be either removed or
properly recompacted, (b) irrigation systems be periodically inspected and maintained to
eliminate leaks and excessive irrigation, and (c) surface drains on and adjacent to slopes be
periodically maintained to preclude ponding or erosion. Although the incorporation of the
above recommendations should reduce the potential for surficial slope instability, it will not
eliminate the possibility, and, therefore, it may be necessary to rebuild or repair a portion of
the project's slopes in the future.
6.12 Storm Water Management
6.12.1 If storm water management devices are not properly designed and constructed, there is a
risk for distress to improvements and property located hydrologically down gradient or
adjacent to these devices. Factors such as the amount of water being detained, its residence
time, and soil permeability have an important effect on seepage transmission and the
potential adverse impacts that may occur if the storm water management features are not
properly designed and constructed. We have not performed a hydrogeological study at the
site. If infiltration of storm water runoff into the subsurface occurs, downstream
improvements may be subjected to seeps, springs, slope instability, raised groundwater,
movement of foundations and slabs, or other undesirable impacts as a result of water
infiltration.
6.12.2 We performed an infiltration study on the property. A summary of our study and storm
water management recommendations are provided in Appendix C. Based on the results of
our study, full and partial infiltration is considered infeasible due to the presence
undocumented fills, low infiltration characteristics, and existing nearby utilities. Basins
should utilize a liner to prevent infiltration from causing adverse settlement, migrating to
adjacent slopes, utilities, and foundations.
Project No. 07516-42-02 - 30 - September 18, 2020
6.13 Site Drainage and Moisture Protection
6.13.1 Adequate site drainage is critical to reduce the potential for differential soil movement,
erosion and subsurface seepage. Under no circumstances should water be allowed to pond
adjacent to footings. The site should be graded and maintained such that surface drainage is
directed away from structures in accordance with 2019 CBC 1803.3 or other applicable
standards. In addition, surface drainage should be directed away from the top of slopes into
swales or other controlled drainage devices. Roof and pavement drainage should be directed
into conduits that carry runoff away from the proposed structure.
6.13.2 In the case of basement walls or building walls retaining landscaping areas, a water-proofing
system should be used on the wall and joints, and a Miradrain drainage panel (or similar)
should be placed over the waterproofing. The project architect or civil engineer should
provide detailed specifications on the plans for all waterproofing and drainage.
6.13.3 Underground utilities should be leak free. Utility and irrigation lines should be checked
periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil
movement could occur if water is allowed to infiltrate the soil for prolonged periods of time.
6.13.4 Landscaping planters adjacent to paved areas are not recommended due to the potential for
surface or irrigation water to infiltrate the pavement's subgrade and base course. We
recommend that subdrains to collect excess irrigation water and transmit it to drainage
structures, or impervious above-grade planter boxes be used. In addition, where landscaping
is planned adjacent to the pavement, we recommend construction of a cutoff wall along the
edge of the pavement that extends at least 6 inches below the bottom of the base material.
6.14 Grading and Foundation Plan Review
6.14.1 Geocon Incorporated should review the grading plans and foundation plans for the project
prior to final design submittal to evaluate whether additional analyses and/or
recommendations are required.
Project No. 07516-42-02 September 18, 2020
LIMITATIONS AND UNIFORMITY OF CONDITIONS
1. The firm that performed the geotechnical investigation for the project should be retained to
provide testing and observation services during construction to provide continuity of
geotechnical interpretation and to check that the recommendations presented for
geotechnical aspects of site development are incorporated during site grading, construction
of improvements, and excavation of foundations. If another geotechnical firm is selected to
perform the testing and observation services during construction operations, that firm should
prepare a letter indicating their intent to assume the responsibilities of project geotechnical
engineer of record. A copy of the letter should be provided to the regulatory agency for their
records. In addition, that firm should provide revised recommendations concerning the
geotechnical aspects of the proposed development, or a written acknowledgement of their
concurrence with the recommendations presented in our report. They should also perform
additional analyses deemed necessary to assume the role of Geotechnical Engineer of
Record.
2. The recommendations of this report pertain only to the site investigated and are based upon
the assumption that the soil conditions do not deviate from those disclosed in the
investigation. If any variations or undesirable conditions are encountered during
construction, or if the proposed construction will differ from that anticipated herein, Geocon
Incorporated should be notified so that supplemental recommendations can be given. The
evaluation or identification of the potential presence of hazardous or corrosive materials was
not part of the scope of services provided by Geocon Incorporated.
3. This report is issued with the understanding that it is the responsibility of the owner or his
representative to ensure that the information and recommendations contained herein are
brought to the attention of the architect and engineer for the project and incorporated into
the plans, and the necessary steps are taken to see that the contractor and subcontractors
carry out such recommendations in the field.
4. The findings of this report are valid as of the present date. However, changes in the
conditions of a property can occur with the passage of time, whether they be due to natural
processes or the works of man on this or adjacent properties. In addition, changes in
applicable or appropriate standards may occur, whether they result from legislation or the
broadening of knowledge. Accordingly, the findings of this report may be invalidated
wholly or partially by changes outside our control. Therefore, this report is subject to review
and should not be relied upon after a period of three years.
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6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:42AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\07516-42-02 Vic Map.dwg
DATE 09 - 18 - 2020
?
?
?
?
?
?
?
A
A'
B
B'
C
C'
D
D'
Qt
Qt
Qt
Qt
Qt
Qt
Qt
Tmv Tmv
Tmv QafTmv
Qaf
Qaf
Qal
Qudf/
Qudf/
Qudf/
T-18
T-19
T-22
T-21
T-20
T-12
T-11
T-23 T-17
T-16
T-14
T-10
T-15
T-13
T-9
T-8
T-4
T-6
T-7
T-5
T-3 T-1
T-2
Qaf
Qaf
Tsdcg
(2)
(2)
(2)
(3)(3)
(2)
(2)
(5)
(3)
(2)
(2)
(2)
(2)
(2)
(3)(2)
(2)
(+18)
(5)
(5)
(9)
(2)
(2)
@7' =
@15' =
@24' =
@29' =
@36' =
@58' =
10-15°
16°
65°
21°
20°
?
11°
?
LD-1
?
?
?
?
A-2
?
A-1
(6)
?
?
??
?
?
?
?
APPROX. LIMITS OF
DISTURBANCE/REMEDIAL
GRADING
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:09/17/2020 10:27AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\SHEETS\07516-42-02 Geo Map.20.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC MAP
NAKANO
CHULA VISTA, CALIFORNIA
60'09 - 18 - 2020
07516 - 42 - 02
1 1 2
........UNDOCUMENTED FILL
........ARTIFICIAL FILL
........ALLUVIUM
........TERRACE DEPOSITS
(Dotted Where Buried)
........SAN DIEGO FORMATION (Conglomerate)
........MISSION VALLEY FORMATION
........APPROX. LOCATION OF GEOLOGIC CONTACT
(Queried Where Uncertain)
........APPROX. LOCATION OF BORING
........APPROX. LOCATION OF INFILTRATION TEST
........APPROX. DEPTH OF REMEDIAL GRADING (In Feet, MSL)
........APPROX. LOCATIION OF GEOLOGIC CROSS SECTION
LD-1
D D'
GEOCON LEGEND
?
Qudf
Qaf
Qal
Qt
Tmv
Tsdcg
(5)
A-2
0 12060 180 240 300 360 420 480 540 720600660 780 840 900 960 114010201080 1200 1260 1320
0 12060 180 240 300 360 420 480 540 720600660 780 840 900 960 114010201080 1200 1260 1320
D I S T A N C E
SCALE: 1" = 60' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION A-A'
D I S T A N C E
SCALE: 1" = 60' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION B-B'
0
60
120
180
240
A
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
B
E
L
E
V
A
T
I
O
N
(
M
S
L
)
A'
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
B'
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
PL
PL
PL
PL
SECTION
C-C'
SECTION
D-D'
SECTION
C-C'
SECTION
D-D'
EAST
EAST
?????????
??
???????????????
???Qaf
Qt
Tmv
Qaf
???????????????
Qudf
Qudf
QtQtQt
Tmv Tmv Tmv
Qt QtQtQt
Tmv TmvTmvTmv
Qaf
QafPROPOSED
GRADE
PROPOSED
GRADE
EXISTING
GRADE
EXISTING
GRADE
??
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:09/17/2020 10:38AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\SHEETS\07516-42-02 XSection.20.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS SECTION
NAKANO
CHULA VISTA, CALIFORNIA
60'09 - 18 - 2020
07516 - 42 - 02
1 2 3
0 12060 180 240 300 360 420 480 540 720600660 780 840 900 960 114010201080
0 12060 180 240 300 360 420 480 540 720600660 780 840 900 960 114010201080 1200
D I S T A N C E
SCALE: 1" = 60' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION C-C'
D I S T A N C E
SCALE: 1" = 60' (Vert. = Horiz.)
GEOLOGIC CROSS-SECTION D-D'
0
60
120
180
240
C
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
D
E
L
E
V
A
T
I
O
N
(
M
S
L
)
C'
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
D'
E
L
E
V
A
T
I
O
N
(
M
S
L
)
0
60
120
180
240
PL
PL
PL
PL
SECTION
B-B'
SECTION
A-A'
SECTION
A-A'
SECTION
B-B'
LD-1
N 5° E
NORTH
????
????
?
?????????
?
?
Qudf
Qudf
Qt
Qt
Qt
Qt
Qt
Tmv
Tmv
Tmv
Tmv
Tmv
Tmv
Tmv
Tmv
PROPOSED
GRADE
PROPOSED
GRADE
EXISTING
GRADE
EXISTING
GRADE
(71)
??
?
??
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF
PROJECT NO.
SCALE DATE
FIGURE
Plotted:09/17/2020 10:38AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\SHEETS\07516-42-02 XSection.20.dwg
GEOTECHNICAL ENVIRONMENTAL MATERIALS
1" =
GEOLOGIC CROSS SECTION
NAKANO
CHULA VISTA, CALIFORNIA
60'09 - 18 - 2020
07516 - 42 - 02
2 2 4
1
1
1
1
2
1
PROPOSED GRADE
EXISTING GRADE
LIMITS OF
REMOVAL
FILL
FORMATIONAL MATERIAL
NOT TO SCALE
NOTE:
SLOPE OF BACKCUT MAY BE STEEPENED WITH THE APPROVAL OF THE PROJECT
ENGINEER/GEOLOGIST WHERE BOUNDARY CONSTRAINTS LIMIT EXTENT OF REMOVALS
UNSUITABLE COMPRESSIBLE
SURFICIAL SEPOSITS
FIG. 5
CONSTRUCTION DETAIL FOR LATERAL EXTENT OF REMOVAL
NO SCALE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:43AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\Lateral Extent of Removal.dwg
DATE 09 - 18 - 2020
REFERENCES :
1......Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954
2......Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
ASSUMED CONDITIONS :
SLOPE HEIGHT
ANALYSIS :
SLOPE INCLINATION
TOTAL UNIT WEIGHT OF SOIL
ANGLE OF INTERNAL FRICTION
APPARENT COHESION
NO SEEPAGE FORCES
EQUATION (3-3), REFERENCE 1
= feet
= pounds per cubic foot
= degrees
C
f
H
gt
f
= pounds per square foot
c =fgH tan
C
EQUATION (3-2), REFERENCE 1FS=gNcfC
H
CALCULATED USING EQ. (3-3)fc =5.6
DETERMINED USING FIGURE 10, REFERENCE 2Ncf=22
FACTOR OF SAFETY CALCULATED USING EQ. (3-2)FS =2.2
t
t
55
120
30
675
2 : 1 (Horizontal : Vertical)
l
l
FIG. 6
SLOPE STABILITY ANALYSIS - CUT SLOPES
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:45AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\Slope Stability Analyses-Cut (SSA-C).dwg
DATE 09 - 18 - 2020
REFERENCES :
1......Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954
2......Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
ASSUMED CONDITIONS :
SLOPE HEIGHT
ANALYSIS :
SLOPE INCLINATION
TOTAL UNIT WEIGHT OF SOIL
ANGLE OF INTERNAL FRICTION
APPARENT COHESION
NO SEEPAGE FORCES
EQUATION (3-3), REFERENCE 1
= feet
= pounds per cubic foot
= degrees
C
f
H
gt
f
= pounds per square foot
c =fgH tan
C
EQUATION (3-2), REFERENCE 1FS=gNcfC
H
CALCULATED USING EQ. (3-3)fc =12.3
DETERMINED USING FIGURE 10, REFERENCE 2Ncf=42
FACTOR OF SAFETY CALCULATED USING EQ. (3-2)FS =2.0
t
t
120
120
30
675
2.5 : 1 (Horizontal : Vertical)
l
l
FIG. 7
SLOPE STABILITY ANALYSIS - NATIVE HILLSIDE
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:47AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\Slope Stability Analyses-Native(SSA-N).dwg
DATE 09 - 18 - 2020
REFERENCES :
1......Janbu, N., Stability Analysis of Slopes with Dimensionless Parameters, Harvard Soil Mechanics,
Series No. 46, 1954
2......Janbu, N., Discussion of J.M. Bell, Dimensionless Parameters for Homogeneous Earth Slopes,
Journal of Soil Mechanics and Foundation Design, No. SM6, November 1967.
ASSUMED CONDITIONS :
SLOPE HEIGHT
ANALYSIS :
SLOPE INCLINATION
TOTAL UNIT WEIGHT OF SOIL
ANGLE OF INTERNAL FRICTION
APPARENT COHESION
NO SEEPAGE FORCES
EQUATION (3-3), REFERENCE 1
= feet
= pounds per cubic foot
= degrees
C
f
H
gt
f
= pounds per square foot
c =fgH tan
C
EQUATION (3-2), REFERENCE 1FS=gNcfC
H
CALCULATED USING EQ. (3-3)fc =
DETERMINED USING FIGURE 10, REFERENCE 2Ncf=
FACTOR OF SAFETY CALCULATED USING EQ. (3-2)FS =
t
t
2.1
13
3.1
10
125
27
300
2 : 1 (Horizontal : Vertical)
l
l
FIG. 8
SLOPE STABILITY ANALYSIS - FILL SLOPES
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:46AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\Slope Stability Analyses-Fill (SSA-F).dwg
DATE 09 - 18 - 2020
ASSUMED CONDITIONS :
SLOPE HEIGHT
ANALYSIS :
SLOPE INCLINATION
SLOPE ANGLE
TOTAL UNIT WEIGHT OF SOIL
ANGLE OF INTERNAL FRICTION
APPARENT COHESION
= Infinite
= pounds per cubic foot
= degrees
C
H
gt
= pounds per square foot
REFERENCES :
1......Haefeli, R. The Stability of Slopes Acted Upon by Parallel Seepage, Proc.
Second International Conference, SMFE, Rotterdam, 1948, 1, 57-62
2......Skempton, A. W., and F.A. Delory, Stability of Natural Slopes in London Clay , Proc.
Fourth International Conference, SMFE, London, 1957, 2, 378-81
DEPTH OF SATURATION
UNIT WEIGHT OF WATER
SLOPE SATURATED TO VERTICAL DEPTH BELOW SLOPE FACE
SEEPAGE FORCES PARALLEL TO SLOPE FACE
Z
= degreesf
= pounds per cubic foot
gw
i
= feetZ
FS == +C -Z cos i tan f( )2
gt Z sin i cos i
gw
gt
62.4
26.6
300
27
125
4
2 : 1 (Horizontal : Vertical)
2.0
FIG. 9
SURFICIAL SLOPE STABILITY ANALYSIS
6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974
PHONE 858 558-6900 - FAX 858 558-6159
DSK/GTYPD PROJECT NO. 07516 - 42 - 02RM / AML
NAKANO
CHULA VISTA, CALIFORNIAGEOTECHNICAL ENVIRONMENTAL MATERIALS
Plotted:09/17/2020 10:49AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\07516-42-02 (Nakano)\DETAILS\Slope Stability Analyses-Surficial (SSAS).dwg
DATE 09 - 18 - 2020
APPENDIX A
Project No. 07516-42-02 September 18, 2020
APPENDIX A
FIELD INVESTIGATION
Our original field investigation performed on April 14, 2005, consisted of a site reconnaissance and
logging of exploratory trenches excavated with a rubber-tired backhoe. The approximate locations of
the exploratory trenches are shown on Figure 2. The backhoe trenches were excavated to depths
between 2 and 18 feet below the existing ground surface using a JD 305 backhoe equipped with a 24-
inch-wide bucket.
Our recent field investigation performed on January 3, 2020, consisted of a site reconnaissance and
logging of one large diameter boring excavated with a truck mounted EZ-Bore drill rig using a 30-inch
diameter bucket auger. The boring was advanced to a depth of 70 feet below existing grades near the
top of slope on the south side of the site. The boring was backfilled in accordance with County of San
Diego guidelines.
For the large diameter boring, the samplers were driven 12 inches into the bottom of the excavations
with the use of a telescoping Kelly bar. The weight of the Kelly bar (4,500 lbs. maximum) drives the
sampler and varies with depth. The height of drop is usually 12 inches. Blow counts are recorded for
every 12 inches the sampler is driven. The penetration resistance values shown on the boring logs are
shown in terms of blows per foot. These values are not to be taken as N-values; adjustments have not
been applied. Elevations shown on the boring logs were determined either from a topographic map or
`by using a benchmark.
The soil conditions encountered in the trenches were visually examined, classified, and logged in
general conformance with the American Society for Testing and Materials (ASTM) Practice for
Description and Identification of Soils (Visual-Manual Procedure D 2488-00). The logs of the
exploratory trenches are presented on Figures A-1 through A-23. The logs depict the various soil types
encountered and indicate the depths at which samples were obtained.
UNDOCUMENTED FILL (Qudf)
Loose to medium dense, damp, grayish-brown, Silty SAND; some cobble,
trace clay
COLLUVIUM (Qcol)
Medium dense, damp, brown and grayish brown, Clayey SAND; some gravel
and cobble. Cobble is sub-rounded up to 10-inch in width
MISSION VALLEY FORMATION (Tmv)
Irregular contact at 6-7 feet
Medium dense to dense, damp, pale yellowish-orange to whitish orange, very
fine grained Silty SAND; micaceous, friable, massive to weakly
laminated/bedded
-At 7 feet: thin 2-inch thick gravel bed. Gravel is sub-rounded 1/2-inch to
3-inch in width. Bedding: N30E/10-15°W (undulatory)
-At 15 feet: grayish white 3/4-inch thick sand bed. Bedding: N5W/16°W
-At 17 feet: 6-inch thick clayey sand/gravel bed; gravel sub-rounded 1/2 to
4-inch in width
Dense, damp, whitish gray, very fine grained Silty SAND; highly micaceous,
abundant lithic grains, weakly to moderately laminated
-At 24 feet: 1/4-1/2-inch sand filled fractures. N5E/65°E
-At 29 feet: bedding N31W/21°W
SM
SC
SM
SM
LD1-1
LD1-2
3
3
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
20
22
24
26
28
Figure A-1,
Log of Boring LD 1, Page 1 of 3
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
EZ BORE PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING LD 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
R. ADAMS CO
N
T
E
N
T
(
%
)
SAMPLE
NO.01-03-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)+/-168'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
-At 30 feet: becomes dense to very dense
-At 36 feet: small 12-inch wide clay filled load structure (small channel).
Bedding: N-S/20°W
-At 38 feet: 4-inch thick gray brown sandy clay bed; not remolded
-At 39 feet: dense, damp, whitish gray, medium coarse sand bed; trace
sub-rounded gravel up to 4-inch in width
-At 40 feet: few oval white-sand filled burrows (krotovina) 2 to 4-inch
diameter.
-At 41 feet: 1/4-inch wide, high angle sand filled fracture with partial caliche
infill.
-At 45 feet: becomes white, fine to medium grained silty sand
-No sample recovery at 50 feet
-At 58 feet: bedding N5E/11°W
SMLD1-3
LD1-4
LD1-5
LD1-5
6
7
10
15
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
Figure A-1,
Log of Boring LD 1, Page 2 of 3
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
EZ BORE PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING LD 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
R. ADAMS CO
N
T
E
N
T
(
%
)
SAMPLE
NO.01-03-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)+/-168'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
Dense to very dense, damp, white to orange-white Silty, fine to medium
SAND; trace gravel, laminated and weakly bedded, friable
TERMINATED AT 71 FEET
No groundwater encountered
Backfilled 01-03-2020
SM
LD1-6 10
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
60
62
64
66
68
70
Figure A-1,
Log of Boring LD 1, Page 3 of 3
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
EZ BORE PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
BORING LD 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
R. ADAMS CO
N
T
E
N
T
(
%
)
SAMPLE
NO.01-03-2020
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)+/-168'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ALLUVIUM
Loose, humid, light brown, Silty, fine-grained SAND with roots
Moderately dense, damp, dark brown, Clayey SAND with trace roots and
gravel
Moderately dense, moist to wet, brown, Clayey SAND with roots and gravel
TERRACE DEPOSIT
Stiff, moist, reddish brown, yellow, gray and black, Cobbly, Clayey GRAVEL
with little fine- to coarse-grained sand, with angular to subrounded gravel and
cobble up to 6" diameter
Dense to very dense, damp, reddish brown, Cobbly SAND with cobble up to
6" diameter
TRENCH TERMINATED AT 10 FEET
SM
SC
SC
SC/CL
SP
T1-1
T1-2
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-2,
Log of Trench T 1, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 1
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)142'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry, reddish brown, Clayey SAND with gravel,
cobbles and roots
TERRACE DEPOSITS
Strong to very strong, humid, reddish brown, Clayey, CONGLOMERATE,
very difficult digging
TRENCH TERMINATED AT 2 FEET
SC
CL
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
Figure A-3,
Log of Trench T 2, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 2
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)160'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose, dry, brown, Sandy COBBLE with cobbles up to 6" diameter with roots
Firm, damp, brown, Sandy CLAY with roots
MISSION VALLEY FORMATION
Moderately dense, weak, humid, tan, Silty, very fine-grained SAND, porous
Dense, humid, weak to friable, deeply weathered, humid, light reddish brown,
fine to medium-grained SANDSTONE
TENCH TERMINATED AT 9 FEET
GP
CL
SM
SM
T3-1
T3-2
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-4,
Log of Trench T 3, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 3
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)170'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry, brown, Sandy COBBLE with roots and
boulders approximately 2 feet in diameter
Firm, humid, brown, Sandy CLAY with roots
MISSION VALLEY FORMATION
Moderately dense to dense, weak to friable, humid, light reddish brown, fine
to medium-grained, SANDSTONE
TRENCH TERMINATED AT 10 FEET
GP
CL
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-5,
Log of Trench T 4, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 4
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)170'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, humid, brown, Silty, fine grained SAND with
roots
TERRACE DEPOSIT
Moderately dense, humid, dark brown, Clayey SAND with gravels and
cobbles
TRENCH TERMINATED AT 12 FEET
SM
SC
T5-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-6,
Log of Trench T 5, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 5
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)135'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, humid, light brown, Silty SAND with roots
COLLUVIUM
Moderately dense to dense, damp to moist, olive brown, Clayey SAND with
cobbles, with roots, cobbles up to 8" diameter
TERRACE DEPOSIT
Stiff, moist, reddish brown, yellow and black, Sandy CLAY with cobbles and
gravel
Dense to very dense, humid, Sandy COBBLES with clay, angular to
sub-rounded cobbles up to 1 foot diameter
TRENCH TERMINATED AT 7 FEET
SM
SC
SC/CL
GC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-7,
Log of Trench T 6, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 6
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)130'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, humid, brown, Silty, fine-grained SAND with
roots
TERRACE DEPOSIT
Moderately dense to dense, damp, brown, Clayey, fine-grained SAND with
gravel and cobbles
Firm to stiff, moist, mottled reddish brown and gray, Sandy CLAY with
gravel and cobbles
Stiff, moist, gray with reddish brown, Silty CLAY with cobbles up to 6"
diameter
TRENCH TERMINATED AT 13 FEET
SM
SC
CL
CL
T7-1
T7-2
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-8,
Log of Trench T 7, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 7
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)125'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, humid, brown, Silty, fine-grained SAND with
roots charcoal and organics
Moderately dense, humid, light reddish brown, Silty SAND with roots
TERRACE DEPOSIT
Moderately dense to dense, damp, dark grayish brown, Clayey SAND with
trace lenses of light reddish brown silty sand
Very dense, humid, dark brown, Clayey SAND
TRENCH TERMINATED AT 5.5 FEET
SM
SM
SC
SC
T8-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
Figure A-9,
Log of Trench T 8, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 8
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)115'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Firm, humid, dark brown, Sandy CLAY with roots and gravel
TERRACE DEPOSIT
Very stiff, humid, dark brown, Silty CLAY with cobbles, with interbedded
gravel and cobble lenses
TRENCH TERMINATED AT 3.5 FEET
CL
CL
121.2 11.9T9-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
Figure A-10,
Log of Trench T 9, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 9
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)110'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry, light brown, Clayey SAND with roots
TERRACE DEPOSIT
Dense, humid to damp, dark brown, Clayey SAND
Very dense, damp, dark brown, Cobbly fine-grained SAND with subangular
to subrounded gravel and cobbles up to 1 foot diameter
Dense, moist, dark reddish brown, Gravelly, fine to medium-grained SAND
with trace cobbles
TRENCH TERMINATED AT 15 FEET
SC
SC
SP
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
Figure A-11,
Log of Trench T 10, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 10
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)105'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Moderately dense, damp, brown, Clayey SAND with roots
TERRACE DEPOSITS
Dense to stiff, moist, reddish brown, Cobbly Sandy CLAY with gravel and
cobbles up to 1 foot diameter
TRENCH TERMINATED AT 7 FEET
SC
GC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-12,
Log of Trench T 11, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 11
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Very loose to loose, dry, light brown to white, Silty, fine-grained SAND with
roots, with plastic
Loose to moderately dense, humid, light reddish brown, Silty, fine-grained
SAND with roots
Moderately dense, humid, light brown, Silty, fine-grained SAND with roots
Moderately dense to dense, humid, dark brown, Sandy COBBLES with
asphalt debris
Moderately dense, humid, olive, Silty, fine-gained SAND with plastic and
cobbles
Moderately dense, moist, greenish gray, Silty, fine-grained SAND with plastic
pipe with cobbles up to 1.5 feet in diameter
TRENCH TERMINATED AT 18 FEET
SM
SM
SM
GP-GM
SM
SM
T12-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
16
18
Figure A-13,
Log of Trench T 12, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 12
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-14-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Moderately dense, dry to damp, brown, Silty, fine-grained SAND with roots
TERRACE DEPOSIT
Moderately dense, moist, dark brown, Clayey, fine-grained SAND with
carbonate
Stiff to very stiff, moist, dark brown, Sandy CLAY
Dense to very dense, damp, brown, Gravelly, fine to medium grained SAND
with subrounded to subangular gravel and cobbles up to 4" diameter
TRENCH TERMINATED AT 14 FEET
SM
SC
CL
SP
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
14
Figure A-14,
Log of Trench T 13, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 13
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)105'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Moderately dense, dry to damp, brown, Silty, fine-grained SAND with roots
TERRACE DEPOSIT
Moderately dense, moist, dark brown, Clayey, fine-grained SAND with
carbonate
Dense, moist, dark brown, Clayey, fine-grained SAND with trace gravel
Dense to very dense, damp, brown, Gravelly, fine to medium-grained SAND
with cobbles up to 6" diameter, cobbles and gravel subrounded
TRENCH TERMINATED AT 10 FEET
SM
SC
SC
SP
T14-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-15,
Log of Trench T 14, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 14
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)105'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry to humid, light brown, Silty, fine-grained
SAND with roots
TERRACE DEPOSIT
Moderately dense, damp to moist, reddish brown, Clayey, fine-grained SAND
with micas
Moderately dense to dense, moist, Clayey, fine-grained SAND
Firm to stiff, damp, mottled reddish brown and dark brown, Sandy CLAY
TRENCH TERMINATED AT 10 FEET
SM
SC
SC
CL
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-16,
Log of Trench T 15, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 15
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)110'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry to damp, light brown, Silty, fine- grained
SAND with roots
TERRACE DEPOSIT
Moderately dense, damp, light reddish brown, Silty, fine-grained SAND with
carbonate
Moderately dense to dense, moist, dark brown, Clayey, fine-grained SAND
TRENCH TERMINATED AT 10 FEET
SM
SM
SC
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-17,
Log of Trench T 16, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 16
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)115'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry, light brown, Silty, fine-grained SAND with
roots
TERRACE DEPOSIT
Moderately dense, moist, light reddish brown, Clayey, fine-grained SAND
with carbonate
Moderately dense to dense, moist, dark brown, Clayey, fine-grained SAND
with granitic floater boulders
Dense, moist, mottled reddish brown and dark brown Sandy CLAY
TRENCH TERMINATED AT 8 FEET
SM
SC
SC
CL
99.4 18.0T17-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
Figure A-18,
Log of Trench T 17, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 17
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)105'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry to humid, light brown, Silty SAND with roots
TERRACE DEPOSIT
Firm to stiff, damp to moist, dark brown with white specs, Sandy CLAY with
carbonate
Dense to very dense, damp, reddish brown, Gravelly, fine to coarse grained
SAND, with subrounded gravel and cobbles up to 6" diameter
TRENCH TERMINATED AT 12 FEET
SM
CL
SP
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
12
Figure A-19,
Log of Trench T 18, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 18
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)110'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
TOPSOIL
Loose to moderately dense, dry to humid, light brown, Silty SAND with roots
TERRACE DEPOSIT
Firm to stiff, damp to moist, dark brown with white specs, Sandy CLAY with
abundant carbonate
Dense, damp, reddish brown, Clayey, fine-grained SAND
Dense to very dense, damp, reddish brown, GRAVELLY, medium-to
coarse-grained SAND with subrounded gravels and cobbles up to 4" diameter
TRENCH TERMINATED AT 10 FEET
SM
CL
SC
SP
104.0 13.8T19-1
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-20,
Log of Trench T 19, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 19
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)105'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Loose to moderately dense, dry to humid, light borwn, Silty, fine-grained
SAND with plastic debris and roots
ALLUVIUM
Stiff, damp, dark brown, Sandy CLAY with trace gravel
TERRACE DEPOSIT
Dense, damp, dark reddish brown, Clayey Sandy COBBLES with subrounded
gravel and cobbles
TRENCH TERMINATED AT 6 FEET
SM
CL
GP
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-21,
Log of Trench T 20, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 20
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Very loose to loose, damp, light reddish brown, Silty SAND with gravel with
roots
Loose to moderately dense, moist, mottled dark brown and olive, Clayey
SAND
TERRACE DEPOSIT
Moderately dense to very dense, moist, reddish brown, Gravelly, medium to
coarse-grained SAND with subrounded gravel and cobbles up to 1 foot
diameter
TRENCH TERMINATED AT 7 FEET
SM
SC
SP
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-22,
Log of Trench T 21, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 21
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Loose, dry to damp, brown, Silty SAND with debris greater than 2 feet
diameter asphalt concrete curb, brick, plastic and wood
TOPSOIL
Firm, moist, black, Sandy CLAY with gravel
TERRACE DEPOSIT
Dense, moist, reddish brown, Gravelly Cobbly SAND with subrounded gravel
and cobbles to 1 foot diameter
TRENCH TERMINATED AT 10 FEET
SM
CL
SP
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
8
10
Figure A-23,
Log of Trench T 22, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 22
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
ARTIFICIAL FILL
Firm, moist, light brown to brown, Sandy CLAY with rock fragments
TOPSOIL
Moderately dense, moist, dark brown, Clayey SAND
TERRACE DEPOSIT
Moderately dense, reddish brown, Clayey SAND with cobbles and boulders
up to 1.5 foot diameter
Dense, damp to moist, reddish brown, Silty, fine to medium grained SAND
with cobbles
TRENCH TERMINATED AT 6 FEET
CL
SC
SC
SM
... DISTURBED OR BAG SAMPLE
GEOCON
DEPTH
IN
FEET
0
2
4
6
Figure A-24,
Log of Trench T 23, Page 1 of 1
DR
Y
D
E
N
S
I
T
Y
(P
.
C
.
F
.
)
... DRIVE SAMPLE (UNDISTURBED)
JD 305 PE
N
E
T
R
A
T
I
O
N
RE
S
I
S
T
A
N
C
E
(B
L
O
W
S
/
F
T
.
)
TRENCH T 23
... CHUNK SAMPLE
DATE COMPLETED
... SAMPLING UNSUCCESSFUL
SOIL
CLASS
(USCS)
GR
O
U
N
D
W
A
T
E
R
C. JENSEN CO
N
T
E
N
T
(
%
)
SAMPLE
NO.04-15-2005
SAMPLE SYMBOLS
... WATER TABLE OR SEEPAGE
MO
I
S
T
U
R
E
BY:EQUIPMENT
ELEV. (MSL.)100'
07516-42-02.GPJ
MATERIAL DESCRIPTION
LI
T
H
O
L
O
G
Y
... STANDARD PENETRATION TEST
NOTE:
PROJECT NO.
THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT
IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES.
07516-42-02
APPENDIX B
Project No. 07516-42-01 - B-1 - September 18, 2005
APPENDIX B
LABORATORY TESTING
Laboratory tests were performed in accordance with generally accepted test methods of the American
Society for Testing and Materials (ASTM) or other suggested procedures. Selected samples were tested
for expansion potential, maximum dry density and optimum moisture content, shear strength
characteristics and sulfate content. The results of these tests are summarized on Tables B-I through B-IV.
TABLE B-I
SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS
ASTM D 4829-03
Sample No.
Moisture Content (%) Dry
Density (pcf)
Expansion
Index Before Test After Test
T1-2 10.4 21.4 108.7 51
T3-2 12.1 23.3 101.9 31
T7-1 10.7 22.5 106.4 49
T12-1 12.8 21.1 100.4 1
TABLE B-II
SUMMARY OF LABORATORY MAXIMUM DRY DENSITY
AND OPTIMUM MOISTURE CONTENT TEST RESULTS
ASTM D 1557-02
Sample
No. Description Maximum Dry
Density (pcf)
Optimum
Moisture Content
(% dry wt.)
T1-2 Light brown, Clayey GRAVEL with little fine to course Sand 132.6 8.2
T3-2 Light yellowish brown fine Sandy SILT with little Clay 120.5 11.9
TABLE B-III
SUMMARY OF DIRECT SHEAR TEST RESULTS
ASTM D 3080-03
Sample No. Dry Density
(pcf)
Moisture Content
(%)
Unit Cohesion (psf)
[ultimate]
Angle of Shear
Resistance [ultimate]
(degrees)
*T1-2 117.8 9.2 400 18
*T3-2 108.5 11.6 200 36
LD1-2 101.0 14.1 28 [31] 740 [500]
LD1-5 103.1 13.2 29 [28] 900 [870]
* Samples remolded to 90 percent relative density near optimum moisture content.
Project No. 07516-42-02 - B-2 - September 18, 2020
TABLE B-IV
SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS
CALIFORNIA TEST NO. 417
Sample No. Water-Soluble Sulfate(%) Sulfate Class
T1-2 0.088 S0
T3-2 0.026 S0
T7-1 0.054 S0
T12-1 0.008 S0
SAMPLE NO.: GEOLOGIC UNIT:
SAMPLE DEPTH (FT): NATURAL/REMOLDED:
1 K 2 K 4 K AVERAGE
890 2030 4300 --
14.5 13.5 14.3 14.1
103.2 98.0 101.6 101.0
1 K 2 K 4 K AVERAGE
22.3 25.1 23.9 23.8
1310 1750 3050 --
983 1760 3101 --
740
28
500
31
Tmv
20'
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
INITIAL CONDITIONS
N
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
ULTIMATE
RESULTS
PEAK
7516-42-02
NAKANO PROPERTY
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
DIRECT SHEAR - ASTM D 3080
PROJECT NO.:
COHESION, C (PSF)
DRY DENSITY (PCF):
AFTER TEST CONDITIONS
1-2
0
500
1000
1500
2000
2500
3000
3500
0.000 0.050 0.100 0.150 0.200 0.250 0.300
SH
E
A
R
S
T
R
E
S
S
(
P
S
F
)
HORIZONTAL DEFORMATION (IN)
1 K 2 K 4 K
1 K PEAK 2 K PEAK 4 K Peak
1 K ULTIMATE 2 K ULTIMATE 4 K Ultimate
4 K
2 K
1 K
0
1000
2000
3000
4000
5000
6000
7000
0 1000 2000 3000 4000 5000 6000
SH
E
A
R
S
T
R
E
S
S
(
P
S
F
)
NORMAL STRESS (PSF)
SAMPLE NO.: GEOLOGIC UNIT:
SAMPLE DEPTH (FT): NATURAL/REMOLDED:
1 K 2 K 4 K AVERAGE
890 2030 4300 --
13.0 13.7 12.7 13.2
102.8 101.5 104.9 103.1
1 K 2 K 4 K AVERAGE
22.3 23.6 22.0 22.7
1341 2159 3234 --
1177 2200 3070 --
900
29
870
28
Tmv
50'
NORMAL STRESS TEST LOAD
WATER CONTENT (%):
PEAK SHEAR STRESS (PSF):
ULT.-E.O.T. SHEAR STRESS (PSF):
INITIAL CONDITIONS
N
FRICTION ANGLE (DEGREES)
NORMAL STRESS TEST LOAD
ACTUAL NORMAL STRESS (PSF):
WATER CONTENT (%):
ULTIMATE
RESULTS
PEAK
7516-42-02
NAKANO PROPERTY
COHESION, C (PSF)
FRICTION ANGLE (DEGREES)
DIRECT SHEAR - ASTM D 3080
PROJECT NO.:
COHESION, C (PSF)
DRY DENSITY (PCF):
AFTER TEST CONDITIONS
1-5
0
500
1000
1500
2000
2500
3000
3500
0.000 0.050 0.100 0.150 0.200 0.250 0.300
SH
E
A
R
S
T
R
E
S
S
(
P
S
F
)
HORIZONTAL DEFORMATION (IN)
1 K 2 K 4 K
1 K PEAK 2 K PEAK 4 K Peak
1 K ULTIMATE 2 K ULTIMATE 4 K Ultimate
4 K
2 K
1 K
0
1000
2000
3000
4000
5000
6000
7000
0 1000 2000 3000 4000 5000 6000
SH
E
A
R
S
T
R
E
S
S
(
P
S
F
)
NORMAL STRESS (PSF)
APPENDIX C
Project No. 07516-42-02 -C-1 - September 18, 2020
APPENDIX C
STORM WATER MANAGEMENT
We understand storm water management devices are being proposed in accordance with the current
Storm Water Standards (SWS). If not properly constructed, there is a potential for distress to
improvements and properties located hydrologically down gradient or adjacent to these devices.
Factors such as the amount of water to be detained, its residence time, and soil permeability have an
important effect on seepage transmission and the potential adverse impacts that may occur if the storm
water management features are not properly designed and constructed. We have not performed a
hydrogeological study at the site. If infiltration of storm water runoff occurs, downstream properties
and improvements may be subjected to seeps, springs, slope instability, raised groundwater, movement
of foundations and slabs, or other undesirable impacts as a result of water infiltration.
Hydrologic Soil Group
The United States Department of Agriculture (USDA), Natural Resources Conservation Services,
possesses general information regarding the existing soil conditions for areas within the United States.
The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the descriptions of
the hydrologic soil groups. In addition, the USDA website also provides an estimated saturated
hydraulic conductivity for the existing soil.
TABLE C-1
HYDROLOGIC SOIL GROUP DEFINITIONS
Soil Group Soil Group Definition
A
Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist
mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a
high rate of water transmission.
B
Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of
moderately deep or deep, moderately well drained or well drained soils that have moderately
fine texture to moderately coarse texture. These soils have a moderate rate of water
transmission.
C
Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a
layer that impedes the downward movement of water or soils of moderately fine texture or fine
texture. These soils have a slow rate of water transmission.
D
Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These
consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table,
soils that have a claypan or clay layer at or near the surface, and soils that are shallow over
nearly impervious material. These soils have a very slow rate of water transmission.
Project No. 07516-42-02 -C-2 - September 18, 2020
The property is underlain by undocumented fill, surficial deposits such as topsoil, colluvium and
alluvium, Terrace Deposits, and the Mission Valley Formation. Table C-2 presents the information from
the USDA website for the subject property.
TABLE C-2
USDA WEB SOIL SURVEY – HYDROLOGIC SOIL GROUP
Map Unit Name Map Unit
Symbol
Approximate
Percentage
of Property
Hydrologic
Soil Group
Olivenhain cobbly loam, 9 to 30 percent slopes OhE 5.0 D
Riverwash Rm 18.5 D
Salinas clay loam, 0 to 2 percent slopes,
warm MAAT, MLRA 19 SbA 76.6 C
Infiltration Testing
We performed two borehole infiltration tests at the locations shown on Figure 2. The tests were
performed in 8-inch-diameter, drilled borings. Table C-3 presents the results of the testing. The
calculation sheets are provided herein.
We used the guidelines presented in the Riverside County Low Impact Development BMP Design
Handbook. Based on this widely accepted guideline, the saturated hydraulic conductivity (Ksat) is
equivalent to the infiltration rate. Therefore, the Ksat value determined from our testing is assumed to
be the unfactored infiltration rate.
TABLE C-3
UNFACTORED, FIELD-SATURATED, INFILTRATION TEST RESULTS
Test No. Depth (inches) Geologic Unit Field Infiltration
Rate, I (in/hr)
Factored* Field
Infiltration Rate, I (in/hr)
A-1 68 Qudf 0.004 0.002
A-2 92 Qudf 0.244 0.12
* Factor of Safety of 2.0 for feasibility determination.
STORM WATER MANAGEMENT CONCLUSIONS
Soil Types
Undocumented Fill (Qpudf) – We encountered undocumented fill up to 18 feet thick at the north end
of the property. The undocumented fill within structural improvement areas will be removed and
replaced with compacted fill. Water that is allowed to migrate into the undocumented fill or
Project No. 07516-42-02 -C-3 - September 18, 2020
compacted fill will cause settlement. Therefore, full and partial infiltration should be considered
infeasible within fill.
Topsoil (Unmapped) – We encountered topsoil varying between 0.5 and 3 feet thick across the site.
Topsoil within structural improvement areas will be removed and replaced with compacted fill. Water
that is allowed to migrate into the topsoil will cause settlement. Therefore, full and partial infiltration
should be considered infeasible within topsoil.
Colluvium (Qcol) – We encountered colluvium on the north-facing slopes at the south property
boundary, varying between 0.5 and 5 feet thick. Colluvium within structural improvement areas will
be removed and replaced with compacted fill. Water that is allowed to migrate into colluvium will
cause settlement. Therefore, full and partial infiltration should be considered infeasible within areas
underlain by colluvium.
Alluvium (Qal) – Alluvium is present in a drainage located at the southeast corner of the property.
Alluvium was also encountered in Trench T-20 beneath undocumented fill at the north end of the site.
Alluvium within structural improvement areas will be removed and replaced with compacted fill.
Water that is allowed to migrate into alluvium will cause settlement. Therefore, full and partial
infiltration should be considered infeasible within areas underlain by alluvium.
Terrace Deposits (Qt) – We encountered Terrace Deposits underlying most of the site below the
artificial fill, topsoil, and alluvium. Infiltration into Terrace Deposits may be possible.
Mission Valley Formation (Tmv) – We encountered age Mission Valley in slopes along the southern
portion of the site. Mission Valley Formation may also be present underlying the Terrace Deposits in
the central portion of the site Infiltration into the Mission Valley Formation is not feasible due to low
infiltration characteristics.
Groundwater Elevation
Groundwater was not encountered in our borings or trenches to a depths explored. Infiltration should
not impact groundwater.
Existing Utilities
Existing utilities are located on the north side of the property and along the west and east property
margins. Infiltration near these utilities is considered infeasible. Otherwise, infiltration due to utility
concerns would be feasible.
Project No. 07516-42-02 -C-4 - September 18, 2020
Soil or Groundwater Contamination
We are unaware of contaminated soil or groundwater on the property. Therefore, full and partial
infiltration associated with this risk is considered feasible.
Slopes
There are no existing slopes that would be impacted by infiltration. There are proposed fill slopes
where infiltration adjacent to the slopes is not feasible.
Infiltration Rates
Our test results indicated slow infiltration rates. The factored rates were 0.002 and 0.12 inches per
hour. The infiltration rates are not high enough to support full or partial infiltration in the area of the
proposed BMP.
Storm Water Management Devices
Liners should be incorporated in the proposed basin. The liner should be impermeable (e.g. High-
density polyethylene, HDPE, with a thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC).
Penetration of the liners should be properly sealed. The devices should also be installed in accordance
with the manufacturer’s recommendations. Overflow protection devices should also be incorporated
into the design and construction of the storm water management device.
Storm Water Standard Worksheets
The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility
Condition (Worksheet C.4-1) worksheet information to help evaluate the potential for infiltration on
the property. The attached Worksheet C.4-1 presents the completed information for the submittal
process.
The regional storm water standards also have a worksheet (Worksheet Form D.5-1) that helps the
project civil engineer estimate the factor of safety based on several factors. Table C-4 describes the
suitability assessment input parameters related to the geotechnical engineering aspects for the factor of
safety determination.
Project No. 07516-42-02 -C-5 - September 18, 2020
TABLE C-4
SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY
SAFETY FACTORS
Consideration High
Concern – 3 Points
Medium
Concern – 2 Points
Low
Concern – 1 Point
Assessment Methods
Use of soil survey maps or
simple texture analysis to
estimate short-term
infiltration rates. Use of
well permeameter or
borehole methods without
accompanying continuous
boring log. Relatively
sparse testing with direct
infiltration methods
Use of well permeameter
or borehole methods with
accompanying continuous
boring log. Direct
measurement of
infiltration area with
localized infiltration
measurement methods
(e.g., Infiltrometer).
Moderate spatial
resolution
Direct measurement with
localized (i.e. small-scale)
infiltration testing
methods at relatively high
resolution or use of
extensive test pit
infiltration measurement
methods.
Predominant
Soil Texture
Silty and clayey soils
with significant fines Loamy soils Granular to slightly
loamy soils
Site Soil Variability
Highly variable soils
indicated from site
assessment or unknown
variability
Soil boring/test pits
indicate moderately
homogenous soils
Soil boring/test pits
indicate relatively
homogenous soils
Depth to Groundwater/
Impervious Layer
<5 feet below
facility bottom
5-15 feet below
facility bottom
>15 feet below
facility bottom
Table C-5 presents the estimated factor values for the evaluation of the factor of safety. This table only
presents the suitability assessment safety factor (Part A) of the worksheet. The project civil engineer
should evaluate the safety factor for design (Part B) and use the combined safety factor for the design
infiltration rate.
TABLE C-5
FACTOR OF SAFETY WORKSHEET D.5-1 DESIGN VALUES1
Suitability Assessment Factor Category Assigned
Weight (w)
Factor
Value (v)
Product
(p = w x v)
Assessment Methods 0.25 2 0.50
Predominant Soil Texture 0.25 3 0.75
Site Soil Variability 0.25 2 0.50
Depth to Groundwater/Impervious Layer 0.25 1 0.25
Suitability Assessment Safety Factor, SA = p 2.0
1 The project civil engineer should complete Worksheet D.5-1 using the data on this table. Additional
information is required to evaluate the design factor of safety.
Project No. 07516-42-02 -C-6 - September 18, 2020
CONCLUSIONS
Our results indicate the site has relatively slow infiltration characteristics. Because of the site
conditions, it is our opinion that there is a potential for lateral water migration. Undocumented and
previously placed fill exists on the property and has a high potential for adverse settlement when
wetted. It is our opinion that full or partial infiltration is infeasible on this site. Our evaluation included
the soil and geologic conditions, estimated settlement and volume change of the underlying soil, slope
stability, utility considerations, groundwater mounding, retaining walls, foundations and existing
groundwater elevations.
Aardvark Permeameter Data Analysis
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:
Borehole Diameter, d (in.):8.00 Ref. EL (feet, MSL):102.0
Borehole Depth, H (in):68.00 Bottom EL (feet, MSL):96.3
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):84.75
Head Height Measured, h (in.):5.50
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.530 319.29 63.858
3 5.00 1.665 46.11 9.222
4 5.00 0.155 4.29 0.858
5 5.00 0.045 1.25 0.249
6 5.00 0.045 1.25 0.249
7 5.00 0.035 0.97 0.194
8 5.00 0.035 0.97 0.194
9 10.00 0.045 1.25 0.125
10 10.00 0.045 1.25 0.125
11 10.00 0.030 0.83 0.083
12 10.00 0.025 0.69 0.069
13 10.00 0.020 0.55 0.055
14 10.00 0.015 0.42 0.042
15 10.00 0.015 0.42 0.042
Steady Flow Rate, Q (in3/min):0.046
Soil Matric Flux Potential, Φm
Φm=0.00060 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =6.07E‐05 in/min 0.004 in/hr
Nakano
07516‐42‐02
A‐1
0.0
0.5
1.0
0 1020304050607080
Q
(
i
n
3/m
i
n
)
Time (min)
Borehole Infiltration Test
Project Name:Date:12/20/2019
Project Number:By:BRK
Test Number:Ref. EL (feet, MSL):100.0
Bottom EL (feet, MSL):92.3
Borehole Diameter, d (in.):8.00
Borehole Depth, H (in):92.00
Distance Between Reservoir & Top of Borehole (in.)26.00
Height APM Raised from Bottom (in.):2.00
Pressure Reducer Used:No
Distance Between Resevoir and APM Float, D (in.):108.75
Head Height Measured, h (in.):4.75
Reading Time Elapsed
(min)
Water Weight
Consummed (lbs)
Water Volume
Consummed (in3)Q (in3/min)
1 0.00 0.000 0.00 0.00
2 5.00 11.255 311.68 62.335
3 5.00 1.095 30.32 6.065
4 5.00 0.315 8.72 1.745
5 5.00 0.995 27.55 5.511
6 5.00 1.075 29.77 5.954
7 5.00 0.985 27.28 5.455
8 5.00 0.915 25.34 5.068
9 5.00 0.890 24.65 4.929
10 5.00 0.845 23.40 4.680
11 5.00 0.770 21.32 4.265
12 5.00 0.740 20.49 4.098
13 5.00 0.695 19.25 3.849
14 5.00 0.665 18.42 3.683
15 5.00 0.655 18.14 3.628
16 6.00 0.750 20.77 3.462
17 4.00 0.440 12.18 3.046
18 5.00 0.565 15.65 3.129
19 5.00 0.535 14.82 2.963
20 5.00 0.530 14.68 2.935
21 5.00 0.510 14.12 2.825
22 6.00 0.610 16.89 2.815
23 4.00 0.405 11.22 2.804
Steady Flow Rate, Q (in3/min):2.815
Soil Matric Flux Potential, Φm
Φm=0.0538 in2/min
Field‐Saturated Hydraulic Conductivity (Infiltration Rate)
K sat =1.37E‐03 in/min 0.082 in/hr
Nakano
07516‐42‐02
A‐2
0.0
5.0
10.0
0 102030405060708090100
Q
(
i
n
3/m
i
n
)
Time (min)
APPENDIX D
APPENDIX D
RECOMMENDED GRADING SPECIFICATIONS
FOR
NAKANO PROPERTY
CHULA VISTA, CALIFORNIA
PROJECT NO. 07516-42-02
GI rev. 07/2015
RECOMMENDED GRADING SPECIFICATIONS
1. GENERAL
1.1 These Recommended Grading Specifications shall be used in conjunction with the
Geotechnical Report for the project prepared by Geocon. The recommendations contained
in the text of the Geotechnical Report are a part of the earthwork and grading specifications
and shall supersede the provisions contained hereinafter in the case of conflict.
1.2 Prior to the commencement of grading, a geotechnical consultant (Consultant) shall be
employed for the purpose of observing earthwork procedures and testing the fills for
substantial conformance with the recommendations of the Geotechnical Report and these
specifications. The Consultant should provide adequate testing and observation services so
that they may assess whether, in their opinion, the work was performed in substantial
conformance with these specifications. It shall be the responsibility of the Contractor to
assist the Consultant and keep them apprised of work schedules and changes so that
personnel may be scheduled accordingly.
1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and
methods to accomplish the work in accordance with applicable grading codes or agency
ordinances, these specifications and the approved grading plans. If, in the opinion of the
Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture
condition, inadequate compaction, and/or adverse weather result in a quality of work not in
conformance with these specifications, the Consultant will be empowered to reject the
work and recommend to the Owner that grading be stopped until the unacceptable
conditions are corrected.
2. DEFINITIONS
2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading
work is being performed and who has contracted with the Contractor to have grading
performed.
2.2 Contractor shall refer to the Contractor performing the site grading work.
2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer
or consulting firm responsible for preparation of the grading plans, surveying and verifying
as-graded topography.
2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm
retained to provide geotechnical services for the project.
GI rev. 07/2015
2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner,
who is experienced in the practice of geotechnical engineering. The Soil Engineer shall be
responsible for having qualified representatives on-site to observe and test the Contractor's
work for conformance with these specifications.
2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained
by the Owner to provide geologic observations and recommendations during the site
grading.
2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include
a geologic reconnaissance or geologic investigation that was prepared specifically for the
development of the project for which these Recommended Grading Specifications are
intended to apply.
3. MATERIALS
3.1 Materials for compacted fill shall consist of any soil excavated from the cut areas or
imported to the site that, in the opinion of the Consultant, is suitable for use in construction
of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as
defined below.
3.1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than
12 inches in maximum dimension and containing at least 40 percent by weight of
material smaller than ¾ inch in size.
3.1.2 Soil-rock fills are defined as fills containing no rocks or hard lumps larger than
4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow
for proper compaction of soil fill around the rock fragments or hard lumps as
specified in Paragraph 6.2. Oversize rock is defined as material greater than
12 inches.
3.1.3 Rock fills are defined as fills containing no rocks or hard lumps larger than 3 feet
in maximum dimension and containing little or no fines. Fines are defined as
material smaller than ¾ inch in maximum dimension. The quantity of fines shall be
less than approximately 20 percent of the rock fill quantity.
3.2 Material of a perishable, spongy, or otherwise unsuitable nature as determined by the
Consultant shall not be used in fills.
3.3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as
defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9
GI rev. 07/2015
and 10; 40CFR; and any other applicable local, state or federal laws. The Consultant shall
not be responsible for the identification or analysis of the potential presence of hazardous
materials. However, if observations, odors or soil discoloration cause Consultant to suspect
the presence of hazardous materials, the Consultant may request from the Owner the
termination of grading operations within the affected area. Prior to resuming grading
operations, the Owner shall provide a written report to the Consultant indicating that the
suspected materials are not hazardous as defined by applicable laws and regulations.
3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of
properly compacted soil fill materials approved by the Consultant. Rock fill may extend to
the slope face, provided that the slope is not steeper than 2:1 (horizontal:vertical) and a soil
layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This
procedure may be utilized provided it is acceptable to the governing agency, Owner and
Consultant.
3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the
Consultant to determine the maximum density, optimum moisture content, and, where
appropriate, shear strength, expansion, and gradation characteristics of the soil.
3.6 During grading, soil or groundwater conditions other than those identified in the
Geotechnical Report may be encountered by the Contractor. The Consultant shall be
notified immediately to evaluate the significance of the unanticipated condition.
4. CLEARING AND PREPARING AREAS TO BE FILLED
4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of
complete removal above the ground surface of trees, stumps, brush, vegetation, man-made
structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried
logs and other unsuitable material and shall be performed in areas to be graded. Roots and
other projections exceeding 1½ inches in diameter shall be removed to a depth of 3 feet
below the surface of the ground. Borrow areas shall be grubbed to the extent necessary to
provide suitable fill materials.
4.2 Asphalt pavement material removed during clearing operations should be properly
disposed at an approved off-site facility or in an acceptable area of the project evaluated by
Geocon and the property owner. Concrete fragments that are free of reinforcing steel may
be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this
document.
GI rev. 07/2015
4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or
porous soils shall be removed to the depth recommended in the Geotechnical Report. The
depth of removal and compaction should be observed and approved by a representative of
the Consultant. The exposed surface shall then be plowed or scarified to a minimum depth
of 6 inches and until the surface is free from uneven features that would tend to prevent
uniform compaction by the equipment to be used.
4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or
where recommended by the Consultant, the original ground should be benched in
accordance with the following illustration.
TYPICAL BENCHING DETAIL
Remove All
Unsuitable Material
As Recommended By
Consultant
Finish Grade Original Ground
Finish Slope Surface
Slope To Be Such That
Sloughing Or Sliding
Does Not Occur Varies
“B”
See Note 1
No Scale
See Note 2
1
2
DETAIL NOTES: (1) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit
complete coverage with the compaction equipment used. The base of the key should
be graded horizontal, or inclined slightly into the natural slope.
(2) The outside of the key should be below the topsoil or unsuitable surficial material
and at least 2 feet into dense formational material. Where hard rock is exposed in the
bottom of the key, the depth and configuration of the key may be modified as
approved by the Consultant.
4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture
conditioned to achieve the proper moisture content, and compacted as recommended in
Section 6 of these specifications.
GI rev. 07/2015
5. COMPACTION EQUIPMENT
5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel
wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of
acceptable compaction equipment. Equipment shall be of such a design that it will be
capable of compacting the soil or soil-rock fill to the specified relative compaction at the
specified moisture content.
5.2 Compaction of rock fills shall be performed in accordance with Section 6.3.
6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL
6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with
the following recommendations:
6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should
generally not exceed 8 inches. Each layer shall be spread evenly and shall be
thoroughly mixed during spreading to obtain uniformity of material and moisture
in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock
materials greater than 12 inches in maximum dimension shall be placed in
accordance with Section 6.2 or 6.3 of these specifications.
6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the
optimum moisture content as determined by ASTM D 1557.
6.1.3 When the moisture content of soil fill is below that specified by the Consultant,
water shall be added by the Contractor until the moisture content is in the range
specified.
6.1.4 When the moisture content of the soil fill is above the range specified by the
Consultant or too wet to achieve proper compaction, the soil fill shall be aerated by
the Contractor by blading/mixing, or other satisfactory methods until the moisture
content is within the range specified.
6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly
compacted by the Contractor to a relative compaction of at least 90 percent.
Relative compaction is defined as the ratio (expressed in percent) of the in-place
dry density of the compacted fill to the maximum laboratory dry density as
determined in accordance with ASTM D 1557. Compaction shall be continuous
over the entire area, and compaction equipment shall make sufficient passes so that
the specified minimum relative compaction has been achieved throughout the
entire fill.
GI rev. 07/2015
6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed
at least 3 feet below finish pad grade and should be compacted at a moisture
content generally 2 to 4 percent greater than the optimum moisture content for the
material.
6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To
achieve proper compaction, it is recommended that fill sl opes be over-built by at
least 3 feet and then cut to the design grade. This procedure is considered
preferable to track-walking of slopes, as described in the following paragraph.
6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a
heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height
intervals. Upon completion, slopes should then be track-walked with a D-8 dozer
or similar equipment, such that a dozer track covers all slope surfaces at least
twice.
6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance
with the following recommendations:
6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be
incorporated into the compacted soil fill, but shall be limited to the area measured
15 feet minimum horizontally from the slope face and 5 feet below finish grade or
3 feet below the deepest utility, whichever is deeper.
6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be
individually placed or placed in windrows. Under certain conditions, rocks or rock
fragments up to 10 feet in maximum dimension may be placed using similar
methods. The acceptability of placing rock materials greater than 4 feet in
maximum dimension shall be evaluated during grading as specific cases arise and
shall be approved by the Consultant prior to placement.
6.2.3 For individual placement, sufficient space shall be provided between rocks to allow
for passage of compaction equipment.
6.2.4 For windrow placement, the rocks should be placed in trenches excavated in
properly compacted soil fill. Trenches should be approximately 5 feet wide and
4 feet deep in maximum dimension. The voids around and beneath rocks should be
filled with approved granular soil having a Sand Equivalent of 30 or greater and
should be compacted by flooding. Windrows may also be placed utilizing an
"open-face" method in lieu of the trench procedure, however, this method should
first be approved by the Consultant.
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6.2.5 Windrows should generally be parallel to each other and may be placed either
parallel to or perpendicular to the face of the slope depending on the site geometry.
The minimum horizontal spacing for windrows shall be 12 feet center-to-center
with a 5-foot stagger or offset from lower courses to next overlying course. The
minimum vertical spacing between windrow courses shall be 2 feet from the top of
a lower windrow to the bottom of the next higher windrow.
6.2.6 Rock placement, fill placement and flooding of approved granular soil in the
windrows should be continuously observed by the Consultant.
6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with
the following recommendations:
6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2
percent). The surface shall slope toward suitable subdrainage outlet facilities. The
rock fills shall be provided with subdrains during construction so that a hydrostatic
pressure buildup does not develop. The subdrains shall be permanently connected
to controlled drainage facilities to control post-construction infiltration of water.
6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock
trucks traversing previously placed lifts and dumping at the edge of the currently
placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the
rock. The rock fill shall be watered heavily during placement. Watering shall
consist of water trucks traversing in front of the current rock lift face and spraying
water continuously during rock placement. Compaction equipment with
compactive energy comparable to or greater than that of a 20-ton steel vibratory
roller or other compaction equipment providing suitable energy to achieve the
required compaction or deflection as recommended in Paragraph 6.3.3 shall be
utilized. The number of passes to be made should be determined as described in
Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional
rock fill lifts will be permitted over the soil fill.
6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both
the compacted soil fill and in the rock fill to aid in determining the required
minimum number of passes of the compaction equipment. If performed, a
minimum of three plate bearing tests should be performed in the properly
compacted soil fill (minimum relative compaction of 90 percent). Plate bearing
tests shall then be performed on areas of rock fill having two passes, four passes
and six passes of the compaction equipment, respectively. The number of passes
required for the rock fill shall be determined by comparing the results of the plate
bearing tests for the soil fill and the rock fill and by evaluating the deflection
GI rev. 07/2015
variation with number of passes. The required number of passes of the compaction
equipment will be performed as necessary until the plate bearing deflections are
equal to or less than that determined for the properly compacted soil fill. In no case
will the required number of passes be less than two.
6.3.4 A representative of the Consultant should be present during rock fill operations to
observe that the minimum number of “passes” have been obtained, that water is
being properly applied and that specified procedures are being followed. The actual
number of plate bearing tests will be determined by the Consultant during grading.
6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that,
in their opinion, sufficient water is present and that voids between large rocks are
properly filled with smaller rock material. In-place density testing will not be
required in the rock fills.
6.3.6 To reduce the potential for “piping” of fines into the rock fill from overlying soil
fill material, a 2-foot layer of graded filter material shall be placed above the
uppermost lift of rock fill. The need to place graded filter material below the rock
should be determined by the Consultant prior to commencing grading. The
gradation of the graded filter material will be determined at the time the rock fill is
being excavated. Materials typical of the rock fill should be submitted to the
Consultant in a timely manner, to allow design of the graded filter prior to the
commencement of rock fill placement.
6.3.7 Rock fill placement should be continuously observed during placement by the
Consultant.
7. SUBDRAINS
7.1 The geologic units on the site may have permeability characteristics and/or fracture
systems that could be susceptible under certain conditions to seepage. The use of canyon
subdrains may be necessary to mitigate the potential for adverse impacts associated with
seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of
existing offsite subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500
feet in length should use 6-inch-diameter pipes.
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TYPICAL CANYON DRAIN DETAIL
7.2 Slope drains within stability fill keyways should use 4-inch-diameter (or lager) pipes.
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TYPICAL STABILITY FILL DETAIL
7.3 The actual subdrain locations will be evaluated in the field during the remedial grading
operations. Additional drains may be necessary depending on the conditions observed and
the requirements of the local regulatory agencies. Appropriate subdrain outlets should be
evaluated prior to finalizing 40-scale grading plans.
7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to
mitigate the potential for buildup of water from construction or landscape irrigation. The
subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric.
Rock fill drains should be constructed using the same requirements as canyon subdrains.
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7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during
future development should consist of non-perforated drainpipe. At the non-perforated/
perforated interface, a seepage cutoff wall should be constructed on the downslope side of
the pipe.
TYPICAL CUT OFF WALL DETAIL
7.6 Subdrains that discharge into a natural drainage course or open space area should be
provided with a permanent headwall structure.
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TYPICAL HEADWALL DETAIL
7.7 The final grading plans should show the location of the proposed subdrains. After
completion of remedial excavations and subdrain installation, the project civil engineer
should survey the drain locations and prepare an “as-built” map showing the drain
locations. The final outlet and connection locations should be determined during grading
operations. Subdrains that will be extended on adjacent projects after grading can be placed
on formational material and a vertical riser should be placed at the end of the subdrain. The
grading contractor should consider videoing the subdrains shortly after burial to check
proper installation and functionality. The contractor is responsible for the performance of
the drains.
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8. OBSERVATION AND TESTING
8.1 The Consultant shall be the Owner’s representative to observe and perform tests during
clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in
vertical elevation of soil or soil-rock fill should be placed without at least one field density
test being performed within that interval. In addition, a minimum of one field density test
should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and
compacted.
8.2 The Consultant should perform a sufficient distribution of field density tests of the
compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill
material is compacted as specified. Density tests shall be performed in the compacted
materials below any disturbed surface. When these tests indicate that the density of any
layer of fill or portion thereof is below that specified, the particular layer or areas
represented by the test shall be reworked until the specified density has been achieved.
8.3 During placement of rock fill, the Consultant should observe that the minimum number of
passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant
should request the excavation of observation pits and may perform plate bearing tests on
the placed rock fills. The observation pits will be excavated to provide a basis for
expressing an opinion as to whether the rock fill is properly seated and sufficient moisture
has been applied to the material. When observations indicate that a layer of rock fill or any
portion thereof is below that specified, the affected layer or area shall be reworked until the
rock fill has been adequately seated and sufficient moisture applied.
8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of
rock fill placement. The specific design of the monitoring program shall be as
recommended in the Conclusions and Recommendations section of the project
Geotechnical Report or in the final report of testing and observation services performed
during grading.
8.5 We should observe the placement of subdrains, to check that the drainage devices have
been placed and constructed in substantial conformance with project specifications.
8.6 Testing procedures shall conform to the following Standards as appropriate:
8.6.1 Soil and Soil-Rock Fills:
8.6.1.1 Field Density Test, ASTM D 1556, Density of Soil In-Place By the
Sand-Cone Method.
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8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and
Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth).
8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density
Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound
Hammer and 18-Inch Drop.
8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test.
9. PROTECTION OF WORK
9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide
positive drainage and prevent ponding of water. Drainage of surface water shall be
controlled to avoid damage to adjoining properties or to finished work on the site. The
Contractor shall take remedial measures to prevent erosion of freshly graded areas until
such time as permanent drainage and erosion control features have been installed. Areas
subjected to erosion or sedimentation shall be properly prepared in accordance with the
Specifications prior to placing additional fill or structures.
9.2 After completion of grading as observed and tested by the Consultant, no further
excavation or filling shall be conducted except in conjunction with the services of the
Consultant.
10. CERTIFICATIONS AND FINAL REPORTS
10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil
Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of
elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot
horizontally of the positions shown on the grading plans. After installation of a section of
subdrain, the project Civil Engineer should survey its location and prepare an as-built plan
of the subdrain location. The project Civil Engineer should verify the proper outlet for the
subdrains and the Contractor should ensure that the drain system is free of obstructions.
10.2 The Owner is responsible for furnishing a final as-graded soil and geologic report
satisfactory to the appropriate governing or accepting agencies. The as-graded report
should be prepared and signed by a California licensed Civil Engineer experienced in
geotechnical engineering and by a California Certified Engineering Geologist, indicating
that the geotechnical aspects of the grading were performed in substantial conformance
with the Specifications or approved changes to the Specifications.
Project No. 07516-42-02 September 18, 2020
LIST OF REFERENCES
1.City of San Diego (2008), Seismic Safety Study, Geologic Hazards and Faults, Grid Tile 6,
dated April 3, 2008;
2.FEMA (2012), Flood Map Service Center, FEMA website,
https://msc.fema.gov/portal/home, flood map number 06073C2159G, effective May 16, 2012,
accessed January 15, 2020;
3.Geocon Incorporated, Geotechnical Investigation, Nakano Property, Dennery Ranch Area,
Chula Vista, California, dated May 10, 2005 (Project No. 07516-42-01).
4.Jennings, C. W., 1994, California Division of Mines and Geology, Fault Activity Map of
California and Adjacent Areas, California Geologic Data Map Series Map No. 6.
5.Kennedy, M. P., and S. S. Tan, 2005, Geologic Map of the San Diego 30’x60’ Quadrangle,
California, USGS Regional Map Series Map No. 3, Scale 1:100,000.
6.SEAOC (2019), OSHPD Seismic Design Maps: Structural Engineers Association of
California website, http://seismicmaps.org/, accessed December 10, 2018;
7.USGS (2019), Quaternary Fault and Fold Database of the United States: U.S. Geological
Survey website, https://www.usgs.gov/natural-hazards/earthquake-hazards/faults, accessed
January 14, 2020;
8.Unpublished reports and maps on file with Geocon Incorporated.