HomeMy WebLinkAbout6 -- REVISED Prelim SWQMP (5-28-19)PDP SWQMP Template Date: January 2016
PDP SWQMP
PRIORITY DEVELOPMENT PROJECT (PDP)
STORM WATER QUALITY MANAGEMENT PLAN
FOR
310‐316 K Street
Assessor’s Parcel No.’s: 573‐450‐04 & 573‐450‐05
Design Review 17‐123
TBD
ENGINEER OF WORK:
___________________________________________________________________________________
Wayne W. Chang, MS, PE 46548 (Expires 6/30/2019)
PREPARED FOR:
Floit Properties, Inc.
3565 7th Avenue
San Diego, CA 92103
(619) 294‐3350
PREPARED BY:
Chang
Civil Engineering ◦ Hydrology ◦ Hydraulics ◦ Sedimentation
P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692‐0760
DATE: 10/10/2018
________________________________________________________________________
Approved By: City of Chula Vista Date:
Page intentionally left blank for double‐sided printing
TABLE OF CONTENTS
Acronym Sheet
Preparer's Certification Page
Submittal Record
Project Vicinity Map
Storm Water Requirements Applicability Checklist (Intake Form)
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
Attachment 1: Backup for PDP Pollutant Control BMPs
Attachment 1a: DMA Exhibit
Attachment 1b: Tabular Summary of DMAs and Design Capture Volume Calculations
Attachment 1c: Harvest and Use Feasibility Screening (when applicable)
Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable)
Attachment 1e: Pollutant Control BMP Design Worksheets / Calculations
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
Attachment 3: Structural BMP Maintenance Plan
Attachment 3a: B Structural BMP Maintenance Thresholds and Actions
Attachment 3b: Draft Maintenance Agreement (when applicable)
Attachment 4: Copy of Plan Sheets Showing Permanent Storm Water BMPs
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
CERTIFICATION PAGE
Project Name: 310‐316 K Street
Permit Application Number: DR 17‐123
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, PE Number & Expiration Date
________________________________________________________
Print Name
________________________________________________________
Company
____________________________
Date
Engineer's Seal
Page intentionally left blank for double‐sided printing
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 10/10/2018
☒ Preliminary Design/
Planning/ CEQA
☐ Final Design
Initial Design Review submittal.
2 Click here to enter
a date.
☐ Preliminary Design/
Planning/ CEQA
☐ Final Design
Click here to enter text.
3 Click here to enter
a date.
☐ Preliminary Design/
Planning/ CEQA
☐ Final Design
Click here to enter text.
4 Click here to enter
a date.
☐Preliminary Design/
Planning/ CEQA
☐Final Design
Click here to enter text.
Page intentionally left blank for double‐sided printing
PROJECT VICINITY MAP
Project Name: 310‐316 K Street
Permit Application Number: DR 17‐123
Page intentionally left blank for double‐sided printing
Complete and attach Storm Water Requirements Applicability Checklist
(Intake Form) included in Appendix A.1
Page intentionally left blank for double‐sided printing
Storm Water Requirements Applicability Checklist
(Intake Form)for All Permit Applications
Public Works Department - Storm Water Management Section April 2016
Project Information
Project Address:Project Application Number:
Project Name:APN(s)
Brief Description of Work Proposed:
Owner/Contact Information
Name of Person Completing this Form:
Role: Property Owner Contractor Architect Engineer Other ____________________
Email:Phone:
Signature:Date Completed:
Answer each section below, starting with Section 1 and progressing through each section. Additional
information for determining the requirements is found in the Chula Vista BMP Design Manual available on
the City’s website at http://www.chulavistaca.gov/departments/public-works/services/storm-water-pollution-
prevention/documents-and-reports.
SECTION 1: Storm Water BMP Requirements
Does the project consist of one or both of the following:
x Repair or improvements to an existing building or
structure that donot alter the size such as: tenant
improvements, interior remodeling, electrical
work, fire alarm, fire sprinkler system, HVAC
work, Gas, plumbing, etc.
x Routine maintenance activities such as: roof or
exterior structure surface replacement;
resurfacing existing roadways and parking lots
including digouts, slurry seal, overlay and
restriping; repair damaged sidewalks or
pedestrian ramps on existing roads without
expanding the impervious footprint; routine
replacement of damaged pavement, trenching
and resurfacing associated with utility work (i.e.
sewer, water, gas or electrical laterals, etc.) and
pot holing or geotechnical investigation borings.
Yes Project is NOT Subject to
Permanent Storm Water BMP
requirements, BUT IS subject to
Construction BMP requirements.
Review & sign “Construction
Storm Water BMP Certification
Statement”on page 2.
No Continue to Section 2, page3.
310-316 K Street, Chula Vista, CA 91910
310-316 K Street 573-450-04, 573-450-05
The project proposes a 4-story apartment building on two parcels.
Wayne W. Chang
(858) 692-0760
Print Form
wayne@changconsultants.com
October 10, 2018
Design Review 17-123
There will be 46 dwelling units, a communal area on the first floor, landscape areas, and parking.
City of Chula Vista Storm Water Applicability Checklist (Intake Form) Page 2 of 5
(April 2016)
Construction Storm Water BMP Certification Statement
The following stormwater quality protection measures are required by City Chula Vista Municipal Code
Chapter 14.20 and the City’s Jurisdictional Runoff Management Program.
1. All applicable construction BMPs and non-stormwater discharge BMPs shall be installed and
maintained for the duration of the project in accordance with the Appendix K “Construction BMP
Standards” of the Chula Vista BMP Design Manual.
2.Erosion control BMPs shall be implemented for all portions of the project area in which no work
has been done or is planned to be done over a period of 14 or more days. All onsite drainage
pathways that convey concentrated flows shall be stabilized to prevent erosion.
3. Run-on from areas outside the project area shall be diverted around work areas to the extent
feasible. Run-on that cannot be diverted shall be managed using appropriate erosion and
sediment control BMPs.
4.Sediment control BMPs shall be implemented, including providing fiber rolls, gravel bags, or other
equally effective BMPs around the perimeter of the project to prevent transport of soil and
sediment offsite. Any sediment tracked onto offsite paved areas shall be removed via sweeping at
least daily.
5.Trash and other construction wastes shall be placed in a designated area at least daily and shall
be disposed of in accordance with applicable requirements.
6. Materials shall be stored to avoid being transported in storm water runoff and non-storm water
discharges. Concrete washout shall be directed to a washout area and shall not be washed out to
the ground.
7.Stockpiles and other sources of pollutants shall be covered when the chance of rain within the
next 48 hours is at least 50%.
I certify that the stormwater quality protection measures listed above will be implemented at the project
described on Intake Form. I understand that failure to implement these measures may result in monetary
penalties or other enforcement actions. This certification is signed under penalty of perjury and does not
require notarization.
Name: __________________________________________ Title: ________________________________
Signature: _________________________________________ Date: __________________________
Dan Floit Owner
Oct 10, 2018
City of Chula Vista Storm Water Applicability Checklist (Intake Form) Page 3 of 5
(April 2016)
Section 2: Determine if Project is a Standard Project or Priority Development Project
1. The project is (select one):
New Development
Redevelopment (is the creation and/or replacement of impervious surface on an already developed
site)
2. Is the project in any of the following categories, (a) through (j)?
a. New development that creates 10,000 square feet or more of im pervious surfaces
(collectively over the entire project site). This includes commercial, industrial, residential,
mixed-use, and public development projects on public or private land.
Yes No
b. Redevelopment project that creates and/or replaces 5,000 square feet or more of
impervious surface (collectively over the entire project site on an existing site of 10,000
square feet or more of impervious surfaces). This includes commercial, industrial,
residential, mixed-use, and public development projects on public or private land.
Yes No
c. New development or redevelopment of a restaurant that creates and/or replaces 5,000
square feet or more of impervious surface (collectively over the entire project site). This
category is defined as a facility that sells prepared foods and drinks for consumption,
including stationary lunch counters and refreshment stands selling prepared foods and
drinks for immediate consumption (Standard Industrial Classification Code 5812).
Yes No
d. New development or redevelopment of hillside that creates and/or replaces 5,000 square
feet or more of impervious surface (collectively over the entire project site). This
category includes development on any natural slope that is twenty-five percent or
greater.
Yes No
e. New development or redevelopment of parking lot that creates and/or replaces 5,000
square feet or more of impervious surface (collectively over the entire project site).This
category is defined as a land area or facility for the temporary parking or storage of motor
vehicles used personally, for business, or for commerce.
Yes No
f. New development or redevelopment of Streets, roads, highways, freeways, and
driveways that creates and/or replaces 5,000 square feet or more of impervious surface
(collectively over the entire project site).This category is defined as any paved
impervious surface used for the transportation of automobiles, trucks, motorcycles, and
other vehicles
Yes No
g. New development or redevelopment project that creates and/or replaces 2,500 square
feet or more of impervious surface (collectively over the entire project site), discharging
directly to an Environmentally Sensitive Area (ESA). “Discharging directly to” includes
flow that is conveyed overland a distance of 200 feet or less from the project to t he ESA,
or conveyed in a pipe or open channel any distance as an isolated flow from the project
to the ESA (i.e. not commingled with flows from adjacent lands).
Yes No
h. New development or redevelopment project of automotive repair shops that creates
and/or replaces 5,000 square feet or more of impervious surface. This category is
defined as a facility that is categorized in any one of the following Standard Industrial
Classification (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539.
Yes No
i. New development or redevelopment projects of retail gasoline outlets that creates and/or
replaces 5,000 square feet or more of impervious surface or its projected Average Daily
Traffic (ADT) of 100 or more vehicles per day.
Yes No
j. New development or redevelopment that result in the disturbance of one or more acres of
land and are expected to generate pollutants post construction.
Yes No
City of Chula Vista Storm Water Applicability Checklist (Intake Form) Page 4 of 5
(April 2016)
The project is (select one):
If “No” is checked for every category in Section 2, project is “Standard Development Project”. Site
design and source control BMP requirements apply. Complete and submit Standard SWQMP (refer to
Chapter 4 & Appendix E of the BMP Design Manual for guidance). Continue to Section 4.
If “Yes” is checked for ANY category in Section 2,project is “Priority Development Project (PDP)”.
Complete below, if applicable, and continue to Section 3.
Complete for PDP Redevelopment Projects ONLY:
The total existing (pre-project) impervious area at the project site is: ___________ ft2 (A)
The total proposed newly created or replaced impervious area is __________ ft 2 (B)
Percent impervious surface created or replaced (B/A)*100: _______%
The percent impervious surface created or replaced is (select one based on the above calculation):
less than or equal to fifty percent (50%) –only new impervious areas are considered a PDP
OR
greater than fifty percent (50%) –the entire project site is considered a PDP
Continue to Section 3
Section 3: Determine if project is PDP Exempt
1. Does the project ONLY include new or retrofit sidewalk, bicycle lane or trails that:
x Are designed and constructed to direct storm water runoff to adjacent vegetated areas, or other
non-erodible permeable areas? Or;
x Are designed and constructed to be hydraulically disconnected from paved streets or roads? Or;
x Are designed and constructed with permeable pavements or surfaces in accordance with USEPA
Green Streets guidance?
Yes. Project is PDP Exempt.
Complete and submit Standard SWQMP
(refer to Chapter 4 of the BMP Design
Manual for guidance).Continue to
Section 4.
No. Next question
2.Does the project ONLY include retrofitting or redevelopment of existing paved alleys, streets or roads
designed and constructed in accordance with the Green Streets standards?
Yes. Project is PDP Exempt.
Complete and submit Standard SWQMP
(refer to Chapter 4 of the BMP Design
Manual for guidance).Continue to
Section 4.
No. Project is PDP.
Site design, source control and structural
pollutant control BMPs apply. Complete
and submit PDP SWQMP (refer to
Chapters 4, 5 & 6 of the BMP Design
Manual for guidance). Continue to
Section 4.
52,787
42,885
81.2
City of Chula Vista Storm Water Applicability Checklist (Intake Form) Page 5 of 5
(April 2016)
SECTION 4: Construction Storm Water BMP Requirements:
All construction sites are required to implement construction BMPs in accordance with the performance
standards in the BMP Design Manual. Some sites are additionally required to obtain coverage under the
State Construction General Permit (CGP), which is administered by the State Water Resource Control
Board.
1. Does the project include Building/Grading/Construction permits proposing less than 5,000 square feet
of ground disturbance and has less than 5-foot elevation change over the entire project area?
Yes; review & sign Construction Storm Water Certification
Statement, skip questions 2-4
No; next question
2. Does the project propose construction or demolition activity, including but not limited to, clearing
grading, grubbing, excavation, or other activity that results in ground disturbance of less than one acre
and more than 5,000 square feet?
Yes. complete & submit Construction Storm Water Pollution
Control Plan (CSWPCP), skip questions 3-4
No; next question
3.Does the project results in disturbance of an acre or more of total land area and are considered regular
maintenance projects performed to maintain original line and grade, hydraulic capacity, or original
purpose of the facility? (Projects such as sewer/storm drain/utility replacement)
Yes. complete & submit Construction Storm Water Pollution
Control Plan (CSWPCP), skip question 4
No; next question
4. Is the project proposing land disturbance greater than or equal to one acre OR the project is part of a
larger common plan of development disturbing 1 acre or more?
Yes; Storm Water Pollution Prevention Plan (SWPPP) is required. Refer to online CASQA or
Caltrans Template. Visit the SWRCB web site at
http://www.waterboards.ca.gov/water_issues/programs/stormwater/construction.shtml .
Note: for Projects that result in disturbance of one to five acres of total land area and can demonstrate that
there will be no adverse water quality impacts by applying for a Construction Rainfall Erosivity Waiver, may
be allowed to submit a CSWPCP in lieu of a SWPPP.
Page intentionally left blank for double‐sided printing
Site Information Checklist
For PDPs
Form I‐3B
(for PDPs)
Project Summary Information
Project Name 310‐316 K Street
Project Address
310‐316 K Street, Chula Vista, CA 91910
Assessor's Parcel Number(s) (APN(s)) 573‐450‐04, 573‐450‐05
Permit Application Number DR 17‐123
Project Hydrologic Unit
Select One:
☐ Pueblo San Diego (908)
☒ Sweetwater (909)
☐ Otay (910)
☐ Tijuana (911)
Project Watershed
(Complete Hydrologic Unit, Area, and Subarea
Name with Numeric Identifier)
Sweetwater Hydrologic Unit (909.00), Lower
Sweetwater HA (909.10), Telegraph HSA (909.11)
Parcel Area
(total area of Assessor's Parcel(s) associated
with the project)
1.21 Acres (52,787 Square Feet)
Area to be Disturbed by the Project
(Project Area)
1.21 Acres (52,787 Square Feet)
Project Proposed Impervious Area
(subset of Project Area)
0.98 Acres (42,885 Square Feet)
Project Proposed Pervious Area
(subset of Project Area)
0.23 Acres (9,922 Square Feet)
Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project.
This may be less than the Parcel Area.
The proposed increase or decrease in
impervious area in the proposed condition as
compared to the pre‐project condition.
Decrease by 18.8 %
Form I‐3B Page 2 of 10
Description of Existing Site Condition and Drainage Patterns
Current Status of the Site (select all that apply):
☒ Existing development
☐ Previously graded but not built out
☐ Demolition completed without new construction
☐ Agricultural or other non‐impervious use
☐ Vacant, undeveloped/natural
Description / Additional Information:
The site contains an automotive auto body repair shop surrounded by a paved vehicle storage area.
Existing Land Cover Includes (select all that apply):
☐ Vegetative Cover
☐ Non‐Vegetated Pervious Areas
☒ Impervious Areas
Description / Additional Information:
The entire site is essentially impervious.
Underlying Soil belongs to Hydrologic Soil Group (select all that apply):
☐ NRCS Type A
☐ NRCS Type B
☐ NRCS Type C
☒ NRCS Type D
Approximate Depth to Groundwater (GW):
☐ GW Depth < 5 feet
☐ 5 feet < GW Depth < 10 feet
☐ 10 feet < GW Depth < 20 feet
☒ GW Depth > 20 feet
Existing Natural Hydrologic Features (select all that apply):
☐ Watercourses
☐ Seeps
☐ Springs
☐ Wetlands
☒ None
Description / Additional Information:
The site is fully developed with no natural hydrologic features and surrounded by existing development.
Form I‐3B Page 3 of 10
Description of Existing Site Topography and Drainage
How is storm water runoff conveyed from the site? At a minimum, this description should answer:
(1) whether existing drainage conveyance is natural or urban;
(2) Is runoff from offsite conveyed through the site? if yes, quantify all offsite drainage areas, design
flows, and locations where offsite flows enter the project site, and summarize how such flows
are conveyed through the site;
(3) Provide details regarding existing project site drainage conveyance network, including any
existing storm drains, concrete channels, swales, detention facilities, storm water treatment
facilities, natural or constructed channels; and
(4) Identify all discharge locations from the existing project site along with a summary of
conveyance system size and capacity for each of the discharge locations. Provide summary of
the pre‐project drainage areas and design flows to each of the existing runoff discharge
locations.
Description / Additional Information:
The on‐site storm runoff sheet flows in a southwesterly direction across the site over rooftops and the
paved ground surface. There is no off‐site runon. The runoff discharges from the site at its southwest
corner. The drainage study in Attachment 5 shows that the existing condition 100‐year runoff is 6.0 cfs
from a 2.14 acre drainage area.
Form I‐3B Page 4 of 10
Description of Proposed Site Development and Drainage Patterns
Project Description / Proposed Land Use and/or Activities:
The project consists of one building situated on two parcels on K Street in the city of Chula Vista. The
building will have 4 stories containing 46 dwelling units and a communal area on the first floor. The site
will also include landscaped areas, surface parking and amenities such as a community room, an
elevator, and a separate trash collection area.
List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots,
courtyards, athletic courts, other impervious features):
The impervious features include the building, parking/driveway area, and hardscaping as well as curb,
gutter, and site on K Street along the project frontage.
List/describe proposed pervious features of the project (e.g., landscape areas):
The pervious features include proposed landscaping.
Does the project include grading and changes to site topography?
☒ Yes
☐ No
Description / Additional Information:
Minor grading will be required during construction.
Form I‐3B Page 5 of 10
Does the project include changes to site drainage (e.g., installation of new storm water conveyance
systems)?
☒ Yes
☐ No
If yes, provide details regarding the proposed project site drainage conveyance network, including storm
drains, concrete channels, swales, detention facilities, storm water treatment facilities, natural or
constructed channels, and the method for conveying offsite flows through or around the proposed
project site. Identify all discharge locations from the proposed project site along with a summary of the
conveyance system size and capacity for each of the discharge locations. Provide a summary of pre‐ and
post‐project drainage areas and design flows to each of the runoff discharge locations. Reference the
drainage study for detailed calculations.
Describe proposed site drainage patterns::
Under existing conditions, on‐site storm runoff sheet flows over impervious surfaces to the
southwesterly corner of the site, and then discharges onto adjacent property. Under proposed
conditions, the on‐site storm runoff will be conveyed by private drainage facilities to one of two Bio
Clean Environmental Services, Inc. Modular Wetland System (MWS) Linear BMPs for pollutant control.
The overall on‐site 1.14 acre drainage area will not be altered by the project. The treated runoff will
then be pumped north to K Street, where it will be conveyed by the K Street curb, gutter, and pavement.
The existing and proposed condition runoff ultimately flows to the same location west of the site. The
project will increase the amount of pervious areas, so will redue the 100‐year flow from 6.0 to 5.2 cfs.
Form I‐3B Page 6 of 10
Identify whether any of the following features, activities, and/or pollutant source areas will be present
(select all that apply):
☒ On‐site storm drain inlets
☒ Interior floor drains and elevator shaft sump pumps
☐ Interior parking garages
☒ Need for future indoor & structural pest control
☒ Landscape/Outdoor Pesticide Use
☐ Pools, spas, ponds, decorative fountains, and other water features
☐ Food service
☒ Refuse areas
☐ Industrial processes
☐ Outdoor storage of equipment or materials
☐ Vehicle and Equipment Cleaning
☐ Vehicle/Equipment Repair and Maintenance
☐ Fuel Dispensing Areas
☐ Loading Docks
☒ Fire Sprinkler Test Water
☒ Miscellaneous Drain or Wash Water
☒ Plazas, sidewalks, and parking lots
Description / Additional Information:
The apartment project will include the checked features and activities.
Form I‐3B Page 7 of 10
Identification and Narrative of Receiving Water and Pollutants of Concern
Describe flow path of storm water from the project site discharge location(s), through urban storm
conveyance systems as applicable, to receiving creeks, rivers, and lagoons as applicable, and ultimate
discharge to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable):
The existing site runoff primarily flows towards its southwest corner, and then across adjacent parcels
before continuing west to a public storm drain in Fourth Avenue. The storm drain continues north along
Fourth Avenue, turns west along J Street, extends south along the east side of the Metropolitan Transit
(trolley) tracks, and then crosses west under Interstate 5 before discharging into a concrete channel. The
concrete channel continues west approximately 465 feet before discharging into San Diego Bay.
The proposed runoff will flow west along K Street to Fourth Avenue, and then follow the existing
drainage path described above.
List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific
Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing
impairment, and identify any TMDLs and/or Highest Priority Pollutants from the WQIP for the impaired
water bodies:
303(d) Impaired Water Body Pollutant(s)/Stressor(s)
TMDLs/ WQIP Highest Priority
Pollutant
San Diego Bay PCBs
Indicator bacteria, dissolved
copper, lead, and zinc (wet
weather).
San Diego Bay, Chula Vista
Marina Copper
Indicator bacteria, dissolved
copper, lead, and zinc (wet
weather).
Click here to enter text Click here to enter text. Click here to enter text.
Identification of Project Site Pollutants*
*Identification of project site pollutants is only required if flow‐thru treatment BMPs are
implemented onsite in lieu of retention or biofiltration BMPs (note the project must also participate in
an alternative compliance program unless prior lawful approval to meet earlier PDP requirements is
demonstrated)
Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see BMP
Design Manual Appendix B.6):
Pollutant
Not Applicable to the
Project Site
Anticipated from the
Project Site
Also a Receiving Water
Pollutant of Concern
Sediment ☐ ☒ ☐
Nutrients ☐ ☒ ☐
Heavy Metals ☐ ☒ ☒
Organic Compounds ☐ ☒ ☐
Trash & Debris ☐ ☒ ☐
Oxygen Demanding
Substances ☐ ☒ ☐
Oil & Grease ☐ ☒ ☐
Bacteria & Viruses ☐ ☒ ☐
Pesticides ☐ ☒ ☐
Form I‐3B Page 8 of 10
Hydromodification Management Requirements
Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)?
☐ Yes, hydromodification management flow control structural BMPs required.
☒ No, the project will discharge runoff directly to existing underground storm drains discharging
directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean.
☐ No, the project will discharge runoff directly to conveyance channels whose bed and bank are
concrete‐lined all the way from the point of discharge to water storage reservoirs, lakes,
enclosed embayments, or the Pacific Ocean.
☐ No, the project will discharge runoff directly to an area identified as appropriate for an exemption by
the WMAA for the watershed in which the project resides.
Description / Additional Information (to be provided if a 'No' answer has been selected above):
See hydromodification exemption letter in Attachment 2.
Critical Coarse Sediment Yield Areas*
*This Section only required if hydromodification management requirements apply
Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist
within the project drainage boundaries?
☐ Yes
☒ No, No critical coarse sediment yield areas to be protected based on WMAA maps
If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been
performed?
☐ 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite
☐ 6.2.2 Downstream Systems Sensitivity to Coarse Sediment
☐ 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite
☐ No optional analyses performed, the project will avoid critical coarse sediment yield areas identified
based on WMAA maps
If optional analyses were performed, what is the final result?
☐ No critical coarse sediment yield areas to be protected based on verification of GLUs onsite
☐ Critical coarse sediment yield areas exist but additional analysis has determined that protection is not
required. Documentation attached in Attachment 2.b of the SWQMP.
☐ Critical coarse sediment yield areas exist and require protection. The project will implement
management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are
identified on the SWQMP Exhibit.
Discussion / Additional Information:
N/A.
Form I‐3B Page 9 of 10
Flow Control for Post‐Project Runoff*
*This Section only required if hydromodification management requirements apply
List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see
Section 6.3.1). For each POC, provide a POC identification name or number correlating to the project's
HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP
Exhibit.
N/A.
Has a geomorphic assessment been performed for the receiving channel(s)?
☐ No, the low flow threshold is 0.1Q2 (default low flow threshold)
☐ Yes, the result is the low flow threshold is 0.1Q2
☐ Yes, the result is the low flow threshold is 0.3Q2
☐ Yes, the result is the low flow threshold is 0.5Q2
If a geomorphic assessment has been performed, provide title, date, and preparer:
N/A.
Discussion / Additional Information: (optional)
N/A.
Form I‐3B Page 10 of 10
Other Site Requirements and Constraints
When applicable, list other site requirements or constraints that will influence storm water
management design, such as zoning requirements including setbacks and open space, or local codes
governing minimum street width, sidewalk construction, allowable pavement types, and drainage
requirements.
N/A.
Optional Additional Information or Continuation of Previous Sections As Needed
This space provided for additional information or continuation of information from previous sections as
needed.
N/A.
Source Control BMP Checklist
for All Development Projects
(Standard Projects and PDPs)
Form I‐4
Project Identification
Project Name: 310‐316 K Street
Permit Application Number: DR 17‐123
Source Control BMPs
All development projects must implement source control BMPs SC‐1 through SC‐6 where applicable and
feasible. See Chapter 4 and Appendix E of the manual for information to implement source control
BMPs shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the source control BMP as described in Chapter 4
and/or Appendix E of the manual. Discussion / justification is not required.
"No" means the BMP is applicable to the project but it is not feasible to implement. Discussion /
justification must be provided.
"N/A" means the BMP is not applicable at the project site because the project does not include
the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage
areas). Discussion / justification may be provided.
Source Control Requirement Applied?
SC‐1 Prevention of Illicit Discharges into the MS4 ☒Yes ☐No ☐N/A
Discussion / justification if SC‐1 not implemented:
Click here to enter text
SC‐2 Storm Drain Stenciling or Signage ☒Yes ☐No ☐N/A
Discussion / justification if SC‐2 not implemented:
Click here to enter text
SC‐3 Protect Outdoor Materials Storage Areas from Rainfall, Run‐On,
Runoff, and Wind Dispersal
☐Yes ☐No ☒N/A
Discussion / justification if SC‐3 not implemented:
Click here to enter text
SC‐4 Protect Materials Stored in Outdoor Work Areas from Rainfall,
Run‐On, Runoff, and Wind Dispersal
☐Yes ☐No ☒N/A
Discussion / justification if SC‐4 not implemented:
Click here to enter text
Form I‐4 Page 2 of 2
Source Control Requirement Applied?
SC‐5 Protect Trash Storage Areas from Rainfall, Run‐On, Runoff, and
Wind Dispersal
☒Yes ☐No ☐N/A
Discussion / justification if SC‐5 not implemented:
Click here to enter text
SC‐6 Additional BMPs Based on Potential Sources of Runoff Pollutants
(must answer for each source listed below)
☒ Onsite storm drain inlets
☒ Interior floor drains and elevator shaft sump pumps
☐ Interior parking garages
☒ Need for future indoor & structural pest control
☒ Landscape/outdoor pesticide use
☐ Pools, spas, ponds, decorative fountains, and other water features
☐ Food service
☒ Refuse areas
☐ Industrial processes
☐ Outdoor storage of equipment or materials
☐ Vehicle and equipment cleaning
☐ Vehicle/equipment repair and maintenance
☐ Fuel dispensing areas
☐ Loading docks
☒ Fire sprinkler test water
☒ Miscellaneous drain or wash water
☒ Plazas, sidewalks, and parking lots
☒Yes
☒Yes
☐Yes
☒Yes
☒Yes
☐Yes
☐Yes
☒Yes
☐Yes
☐Yes
☐Yes
☐Yes
☐Yes
☐Yes
☒Yes
☒Yes
☒Yes
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐No
☐N/A
☐N/A
☒N/A
☐N/A
☐N/A
☒N/A
☒N/A
☐N/A
☒N/A
☒N/A
☒N/A
☒N/A
☒N/A
☒N/A
☐N/A
☐N/A
☐N/A
Discussion / justification if SC‐6 not implemented. Clearly identify which sources of runoff pollutants are
discussed. Justification must be provided for all "No" answers shown above.
Click here to enter text
Site Design BMP Checklist
for All Development Projects
(Standard Projects and PDPs)
Form I‐5
Project Identification
Project Name: 310‐316 K Street
Permit Application Number: DR 17‐123
Site Design BMPs
All development projects must implement site design BMPs SD‐1 through SD‐8 where applicable and
feasible. See Chapter 4 and Appendix E of the manual for information to implement site design BMPs
shown in this checklist.
Answer each category below pursuant to the following.
"Yes" means the project will implement the site design BMP as described in Chapter 4 and/or
Appendix E of the manual. Discussion / justification is not required.
"No" means the BMP is applicable to the project but it is not feasible to implement. Discussion /
justification must be provided.
"N/A" means the BMP is not applicable at the project site because the project does not include
the feature that is addressed by the BMP (e.g., the project site has no existing natural areas to
conserve). Discussion / justification may be provided.
Site Design Requirement Applied?
SD‐1 Maintain Natural Drainage Pathways and Hydrologic Features ☐Yes ☐No ☒N/A
Discussion / justification if SD‐1 not implemented:
Click here to enter text
SD‐2 Conserve Natural Areas, Soils, and Vegetation ☐Yes ☐No ☒N/A
Discussion / justification if SD‐2 not implemented:
Click here to enter text
SD‐3 Minimize Impervious Area ☒Yes ☐No ☐N/A
Discussion / justification if SD‐3 not implemented:
Click here to enter text
SD‐4 Minimize Soil Compaction ☒Yes ☐No ☐N/A
Discussion / justification if SD‐4 not implemented:
Click here to enter text
Form I‐5 Page 2 of 2
Site Design Requirement Applied?
SD‐5 Impervious Area Dispersion ☒Yes ☐No ☐N/A
Discussion / justification if SD‐5 not implemented:
Click here to enter text
SD‐6 Runoff Collection ☒Yes ☐No ☐N/A
Discussion / justification if SD‐6 not implemented:
Click here to enter text.
SD‐7 Landscaping with Native or Drought Tolerant Species ☒Yes ☐No ☐N/A
Discussion / justification if SD‐7 not implemented:
Click here to enter text.
SD‐8 Harvesting and Using Precipitation ☐Yes ☒No ☐N/A
Discussion / justification if SD‐8 not implemented:
Harvest and use is infeasible per Attachment 1c.
Summary of PDP Structural BMPs Form I‐6
(For PDPs)
Project Identification
Project Name: 310‐316 K Street
Permit Application Number: DR 17‐123
PDP Structural BMPs
All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the
manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the
selection process described in Chapter 5. PDPs subject to hydromodification management requirements
must also implement structural BMPs for flow control for hydromodification management (see Chapter
6 of the manual). Both storm water pollutant control and flow control for hydromodification
management can be achieved within the same structural BMP(s).
PDP structural BMPs must be verified by the local jurisdiction at the completion of construction. This
may include requiring the project owner or project owner's representative to certify construction of the
structural BMPs (see Section 1.12 of the manual). PDP structural BMPs must be maintained into
perpetuity, and the local jurisdiction must confirm the maintenance (see Section 7 of the manual).
Use this form to provide narrative description of the general strategy for structural BMP implementation
at the project site in the box below. Then complete the PDP structural BMP summary information sheet
(page 3 of this form) for each structural BMP within the project (copy the BMP summary information
page as many times as needed to provide summary information for each individual structural BMP).
Describe the general strategy for structural BMP implementation at the site. This information must
describe how the steps for selecting and designing storm water pollutant control BMPs presented in
Section 5.1 of the manual were followed, and the results (type of BMPs selected). For projects requiring
hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are
integrated or separate.
The project’s geotechnical engineer has performed testing that determined that full and partial
infiltration is not feasible (see Attachment 6). The project is only subject to pollutant control, and not
flow control (see Attachment 2). As a a result, Modular Wetland System (MWS) Linear BMPs were
selected for the site. MWS Linear BMPs are TAPE certified, so meet local agency requirements.
(Continue on page 2 as necessary.)
Form I‐6 Page 2 of Insert Total Page #
(Page reserved for continuation of description of general strategy for structural BMP implementation
at the site)
(Continued from page 1)
Form I‐6 Page 3 of X (Copy as many as needed)
Structural BMP Summary Information
(Copy this page as needed to provide information for each individual proposed structural BMP)
Structural BMP ID No.: BMP 1 and BMP 2
Construction Plan Sheet No.: C2.0, 3.0, and 5.0
Type of structural BMP:
☐ Retention by harvest and use (HU‐1)
☐ Retention by infiltration basin (INF‐1)
☐ Retention by bioretention (INF‐2)
☐ Retention by permeable pavement (INF‐3)
☐ Partial retention by biofiltration with partial retention (PR‐1)
☐ Biofiltration (BF‐1)
☐ Flow‐thru treatment control with prior lawful approval to meet earlier PDP requirements (provide
BMP type/description in discussion section below)
☐ Flow‐thru treatment control included as pre‐treatment/forebay for an onsite retention or
biofiltration BMP (provide BMP type/description and indicate which onsite retention or
biofiltration BMP it serves in discussion section below)
☐ Flow‐thru treatment control with alternative compliance (provide BMP type/description in discussion
section below)
☐ Detention pond or vault for hydromodification management
☒ Other (describe in discussion section below)
Purpose:
☒ Pollutant control only
☐ Hydromodification control only
☐ Combined pollutant control and hydromodification control
☐ Pre‐treatment/forebay for another structural BMP
☐ Other (describe in discussion section below)
Who will certify construction of this BMP?
Provide name and contact information for the
party responsible to sign BMP verification forms if
required by the City Engineer (See Section 1.12 of
the manual)
TBD
Who will be the final owner of this BMP?
Property owner
Who will maintain this BMP into perpetuity?
Property owner
What is the funding mechanism for maintenance?
Property owner will establish mechanism.
Discussion (as needed):
The project proposes two TAPE‐certified Modular Wetland System (MWS) Linear BMPs for pollutant
control.
Form I‐6 Page 4 of X (Copy as many as needed)
Structural BMP ID No.: BMP 1 and BMP 2
Construction Plan Sheet No.: C2.0, C3.0, and C5.0
Discussion (as needed):
N/A.
ATTACHMENT 1
BACKUP FOR PDP POLLUTANT CONTROL BMPS
This is the cover sheet for Attachment 1.
Page intentionally left blank for double‐sided printing
Indicate which items are included behind this cover sheet:
Attachment
Sequence Contents Checklist
Attachment 1a
DMA Exhibit (Required)
See DMA Exhibit Checklist on the back of
this Attachment cover sheet.
☒ 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
Form I‐8, Categorization of Infiltration
Feasibility Condition (Required unless the
project will use harvest and use BMPs)
Refer to Appendices C and D of the BMP
Design Manual to complete Form I‐8.
☒ 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
Use this checklist to ensure the required information has been included on the DMA Exhibit:
The DMA Exhibit must identify:
☒ 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 demolition
☒ 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)
FS
SD
SD
SD
SD
WS
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
K ETTLER EWECKL
ENGINEERING
Project
TH
E
P
I
C
T
O
R
I
A
L
A
N
D
G
R
A
P
H
I
C
E
X
P
R
E
S
S
I
O
N
S
D
I
S
P
L
A
Y
E
D
W
I
T
H
T
H
I
S
W
O
R
K
A
R
E
C
O
P
Y
R
I
G
H
T
E
D
U
N
D
E
R
T
H
E
L
A
W
S
O
F
T
H
E
U
N
I
T
E
D
S
T
A
T
E
S
,
T
I
T
L
E
1
7
,
U
.
S
.
C
O
D
E
.
U
N
D
E
R
S
E
C
T
I
O
N
1
0
6
O
F
T
H
E
C
O
P
Y
R
I
G
H
T
A
C
T
,
T
H
E
A
R
C
H
I
T
E
C
T
S
H
A
L
L
M
A
I
N
T
A
I
N
T
H
E
E
X
C
L
U
S
I
V
E
R
I
G
H
T
O
F
T
H
E
R
E
P
R
O
D
U
C
T
I
O
N
,
D
I
S
P
L
A
Y
O
R
A
N
Y
D
E
R
I
V
A
T
I
O
N
OF
T
H
I
S
W
O
R
K
.
17-123
10/10/18 Design Review
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
31
0
-
3
1
6
K
S
t
r
e
e
t
,
C
h
u
l
a
V
i
s
t
a
,
C
A
9
1
9
1
1
31
0
-
3
1
6
K
S
t
r
e
e
t
2/11/19 Design Review 2
4/23/19 Design Review 3
5/31/19 Design Review 4
Drainage
Management
Area Plan
C3.0
·
·
·
·
·
·
·
(HMP EXEMPT - DCV ONLY)
FLOW RATE: Q=CIA=(0.76)(0.2)(0.83)*1.5 = 0.19 CFS
BMP NO. 1
MWU SIZE: MWS-L-8-8 (SEE TABLE THIS SHEET)
(HMP EXEMPT - DCV ONLY)
FLOW RATE: Q=CIA=(0.67)(0.2)(0.26)*1.5 = 0.05 CFS
BMP NO. 2
MWU SIZE: MWS-L-4-4 (SEE TABLE THIS SHEET)
Page intentionally left blank for double‐sided printing
Appendix B:
Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
BMP Design Manual-Appendices
December 2015 B-17
Worksheet B.3-1. Harvest and Use Feasibility Screening
Harvest and Use Feasibility Screening Worsksheet B.3-1
1. Is there a demand for harvested water (check all that apply) at the project site that is reliably
present during the wet season?
Toilet and urinal flushing
Landscape irrigation
Other:______________
2. If there is a demand; estimate the anticipated average wet season demand over a period of 36
hours. Guidance for planning level demand calculations for toilet/urinal flushing and landscape
irrigation is provided in Section B.3.2. [Provide a summary of calculations here]
3. Calculate the DCV using worksheet B-2.1.
[Provide a results here]
3a. Is the 36-hour demand
greater than or equal to the
DCV?
Yes / No
3b. Is the 36-hour demand greater
than 0.25DCV but less than the full
DCV?
Yes / No
3c. Is the 36-hour
demand less than
0.25DCV?
Yes
Harvest and use appears to be
feasible. Conduct more detailed
evaluation and sizing
calculations to confirm that
DCV can be used at an adequate
rate to meet drawdown criteria.
Harvest and use may be feasible.
Conduct more detailed evaluation and
sizing calculations to determine
feasibility. Harvest and use may only
be able to be used for a portion of the
site, or (optionally) the storage may
need to be upsized to meet long term
capture targets while draining in
longer than 36 hours.
Harvest and use is
considered to be
infeasible.
Appendix B:
Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
BMP Design Manual-Appendices
December 2015 B-20
Table B.3-1. Toilet and Urinal Water Usage per Resident or Employee
Land Use Type
Toilet User
Unit of
Normalization
Per Capita Use per
Day
Visitor
Factor4
Water
Efficiency
Factor
Total Use
per
Resident
or
Employee
Toilet
Flushing1,2 Urinals3
Residential Resident 18.5 NA NA 0.5 9.3
Office Employee
(non-visitor) 9.0 2.27 1.1 0.5
7
(avg)
Retail Employee
(non-visitor) 9.0 2.11 1.4 0.5
Schools Employee
(non-student) 6.7 3.5 6.4 0.5 33
Various
Industrial Uses
(excludes
process water)
Employee
(non-visitor) 9.0 2 1 0.5 5.5
1. Based on American Waterworks Association Research Foundation,1999. Residential End Uses of Water.
Denver, CO: AWWARF
2. Based on use of 3.45 gallons per flush and average number of per employee flushes per subsector, Table D-
1 for MWD (Pacific Institute, 2003)
3. Based on use of 1.6 gallons per flush, Table D-4 and average number of per employee flushes per
subsector, Appendix D (Pacific Institute, 2003)
4. Multiplied by the demand for toilet and urinal flushing for the project to account for visitors. Based on
proportion of annual use allocated to visitors and others (includes students for schools; about 5 students
per employee) for each subsector in Table D-1 and D-4 (Pacific Institute, 2003)
5. Accounts for requirements to use ultra low flush toilets in new development projects; assumed that
requirements will reduce toilet and urinal flushing demand by half on average compared to literature
estimates. Ultra low flush toilets are required in all new construction in California as of January 1, 1992.
Ultra low flush toilets must use no more than 1.6 gallons per flush and Ultra low flush urinals must use no
more than 1 gallon per flush. Note: If zero flush urinals are being used, adjust accordingly.
Appendix B:
Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods
BMP Design Manual-Appendices
December 2015 B-13
Worksheet B.2-1. DCV
Design Capture Volume Worksheet B-2.1
1 85th percentile 24-hr storm depth from Figure B.1-1 d= inches
2 Area tributary to BMP (s) A= acres
3 Area weighted runoff factor (estimate using Appendix B.1.1
and B.2.1) C= unitless
4 Street trees volume reduction TCV= cubic-feet
5 Rain barrels volume reduction RCV= cubic-feet
6 Calculate DCV =(3630 x C x d x A) – TCV - RCV DCV= cubic-feet
Figure B.1-1: 85th Percentile 24-hour Isopluvial Map
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-11
Worksheet C.4-1: Categorization of Infiltration Feasibility Condition
Categorization of Infiltration Condition Worksheet C.4-1
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences
that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility locations greater
than 0.5 inches per hour? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
Onsite testing using the inverse auger hole, or “Porchet” method evaluated infiltration rates of less than
0.5 inches per hour. See GSI report dated February 23, 2018 for other related discussions and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or
other factors) that cannot be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
See the answer to N o. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-12
Worksheet C.4.1 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of groundwater contamination (shallow water table, storm water pollutants
or other factors) that cannot be mitigated to an acceptable level? The response to
this Screening Question shall be based on a comprehensible evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
See the answer to No. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing
potential water balance issues such as a change of seasonality of ephemeral streams
or increased discharge of contaminated groundwater to surface waters? The
response to this Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
See the answer to N o. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
Part 1
Result*
In the answers to rows 1-4 are “Yes” a full infiltration design is potentially feasible. The feasibility
screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally
be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
Proceed
to Part 2
* 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 [County Engineer] to substantiate findings.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and Groundwater Investigation Requirements
BMP Design Manual-Appendices
December 2015
C-13
Worksheet C.4.1 Page 3 of 4
Part 2 - Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in an appreciable amount be physically feasible without any negative consequences
that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any appreciable
rate or volume? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2 and
Appendix D.
X
Provide basis:
Site specific infiltration testing evaluated infiltration rates (per bio-basin) ranging from 0.031 to 0.064 inches
per hour for onsite soil. The average calculated infiltration rate is ±0.047 inches/hr. Using a minimum FOS
of 2.0, the “reliable infiltration rate” is ±0.02 inches/hr. This is much less than the lower limit of infiltration
recommended by the USEPA (0.52 inches/hr [see Clar, et al., 2004]), and less than that currently allowed
by the City of San Diego (0.05 inches/hr.[see City of San Diego, 2017]). Existing or proposed fill, and/or
moisture sensitive improvements, such as pavements, and utility trench backfill, would likely be adversely
affected, including offsite improvements, causing settlement and distress. See GSI report dated
February 23, 2018 for other related discussions and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
6
Can infiltration in any appreciable quantity be allowed without
increasing risk of geotechnical hazards (slope stability, groundwater
mounding, utilities, or other factors) that cannot be mitigated to an
acceptable level? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2.
X
Provide basis:
The site is underlain by HSG “D” soils. Bio-basins can adversely affect the performance of the onsite and
offsite structures foundation systems by: 1) Increasing soil moisture transmission rates through concrete
flooring; and 2) Increase the potential for a loss in bearing strength of soil, due to saturation. Onsite
mitigative grading of compressible near-surface soils for the support of structures generally involves
removal and recompaction. This is anticipated to create a permeability contrast, and the potential for the
development of a shallow “perched” and mounded water table, which can reasonably be anticipated to
migrate laterally, beneath the structure(s), or offsite onto adjacent property, causing settlement and
associated distress. . Accordingly, infiltrating into site soils is poor engineering judgement. See GSI report
dated February 23, 2018 for other related discussions, and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-14
W orksheet C.4.1 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing
significant risk for groundwater related concerns (shallow water table,
storm water pollutants or other factors)? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
Groundwater was not encountered to depths in excess of 60 feet below existing grades in the general
vicinity of these basins. Marquez Auto Body occupies this site, but is not shown on Geotracker as being
impacted. GSI is not aware of surficial contamination at the site; GSI is also unaware if an environmental
assessment of this site has not been performed. Accordingly, it appears that, based on the available data,
there is not a significa nt risk fo r co ntam ina tion to g ro undw a te r; how ever, new info rm a tion co uld cha ng e this
conclusion.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
8
Can infiltration be allow ed w ithout violating downstream water rights?
The response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
X
Provide basis:
W ater rights are considered a legal matter, and typically do not fall within the purview of geotechnical
engineering. GSI is not aware of any downstream water rights issues of concern on the adjoining
properties. Further, given the low infiltration rate of onsite soils, it does not appear that infiltration should
significantly affect downstream water rights, from a geotechnical perspective. Drainage appears to be
directed offsite and collected within the municipal system.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The
feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No
Infiltration
* 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 Agency/Jurisdictions to substantiate findings.
GSI Appendix F, W .O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix D,” dated December 2015
Appendix D:
Approved Infiltration Rate Assessment M ethods
BMP Design M anual-Appendicies
December 2015 D-17
W orksheet D.5-1: Factor of Safety and Design Infiltration Rate W orksheet
Factor of Safety Infiltration Rate Worksheet Worksheet D.5-1
Factor Criteria Factor Description Assigned
Weight (w)
Factor
Value (v)
Product (p)
p = w x v
A Suitability
Assessment
Soil assessment methods 0.25 2 0.5
Predominant soil texture 0.25 2 0.5
Site soil variability 0.25 1 0.25
Depth to groundwater/impervious layer 0.25 1 0.25
ASuitability Assessment Safety Factor, S = Ep 1.5 Use 2.0
B Design
Level of pretreatment/expected sediment loads 0.5
Redundancy/resiliency 0.25
Compaction during construction 0.25
BDesign Safety Factor, S = Ep
total A BCombined Safety Factor, S = S x S
observedObserved Infiltration Rate, inch/hr, K
(corrected for test-specific bias)
design observed totalDesign Infiltration Rate, in/hr, K = K / S
Supporting Data
Briefly describe infiltration test and provide reference to test forms:
Page intentionally left blank for double‐sided printing
ATTACHMENT 1e
POLLUTANT CONTROL BMP DESIGN
Pollutant control BMPs were selected to treat the project’s pollutants of concern identified on Form
I-3B. Two Bio Clean Environmental Services, Inc. Modular Wetland System Linear BMPs (see
the Attachment 1b and 1b, DMA Exhibit) were used because these have a high pollutant removal
efficiency for the project’s pollutants of concern and are TAPE-certified. Furthermore, infiltration
and partial infiltration are not feasible according to the soils engineer (see Attachment 6). MWS-
Linear have been selected in this entitlement-level SWQMP to demonstrate feasibility of using
compact biofiltration BMPs at the site. Equivalent acceptable compact biofiltration BMPs can be
selected during final engineering.
MWS Linear uses flow-based sizing. The BMP Design Manual, outlines the flow-based sizing
procedure. The rational method is used to determine the treatment control flow rate and has the
following form:
QBMP = CIA where, QBMP = flow-based design flow rate, cfs
C = composite runoff factor for the drainage management areas
I = rainfall intensity = 0.2 inches per hour
A = area tributary to the BMP, acres
The impervious and pervious areas tributary to each MWS Linear are shown and tabulated on
Attachment 1a and 1b. Table 1 summarizes the rational method results for each MWS Linear and
preliminary sizing. The QBMP value is multiplied by 1.5 to compute the design flow rate.
MWS
Linear
C Intensity,
in/hr
Area,
acres
QBMP,
cfs
QDESIGN1,
cfs
MWS-Linear
Model
BMP 1 0.75 0.2 0.83 0.125 0.187 MWS-L-8-8
2
BMP 2 0.75 0.2 0.25 0.038 0.056 MWS-L-4-6
1QDESIGN is 1.5 times QBMP. QDESIGN is used for the flow-based sizing.
2Sizing based on conceptual customized sizing by Bio Clean assuming vault is upstream
of MWS-Linear (see attached)
Table 1. Rational Method Results
Either the de minimis or green street criteria will be used for 4,989 square feet of K Street
improvements (see Attachment 1a and 1b).
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
FLOW-BASED
The MWS Linear can be used in stand-alone applications to meet treatment flow requirements. Since the
MWS Linear 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.
SPECIFICATIONS
ATTACHMENT 2
BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES
This is the cover sheet for Attachment 2.
Page intentionally left blank for double‐sided printing
☒ Mark this box if this attachment is empty because the project is exempt from PDP hydromodification
management requirements.
Indicate which items are included behind this cover sheet:
Attachment
Sequence Contents Checklist
Attachment 2a
Hydromodification Management Exhibit
(Required)
☐ Included
See Hydromodification Management
Exhibit Checklist on the back of this
Attachment cover sheet.
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, including
Structural BMP Drawdown Calculations
and Overflow Design Summary
(Required)
See Chapter 6 and Appendix G of the
BMP Design Manual
☐ Included
☐ Submitted as separate stand‐alone
document
Attachment 2e
Vector Control Plan (Required when
structural BMPs will not drain in 96
hours)
☐ Included
☐ Not required because BMPs will drain
in less than 96 hours
Page intentionally left blank for double‐sided printing
Chang
Civil Engineering◦Hydrology◦Hydraulics◦Sedimentation
P.O. Box 9496
Rancho Santa Fe, CA 92067-4496
T: 858.692.0760
F: 858.832.1402
wayne@changconsultants.com
May 29, 2018
Steve Kettler
Kettler Leweck Engineering
303 A Street, Suite 302
San Diego, CA 92101
Subject: 310-316 K Street, Hydromodification Exemption
Dear Steve:
I have performed a hydromodification assessment of the redevelopment project at 310-316 K
Street and determined that the project is exempt. The site is located on the south side of K Street
approximately 200 feet west of Third Avenue in the city of Chula Vista (see the attached Chula
Vista Drainage Master Plan exhibits). Under pre-project conditions, a site visit and the Drainage
Master Plan exhibits indicate that the site runoff primarily flows towards its southwest corner, and
then across adjacent parcels before continuing west to a public storm drain in Fourth Avenue. The
storm drain continues north along Fourth Avenue, turns west along J Street, extends south along
the east side of the Metropolitan Transit (trolley) tracks, and then crosses west under Interstate 5
before discharging into a concrete channel constructed per Drawing No. 88-107 (see the attached
as-built). The concrete channel continues west approximately 465 feet before discharging into San
Diego Bay.
San Diego Bay is hydromodification exempt per the October 1, 2015, San Diego County Regional
Watershed Management Area Analysis (WMAA). Consequently, the city of Chula Vista’s
December 2015, BMP Design Manual, states that “projects discharging directly to enclosed
embayments (e.g., San Diego Bay or Mission Bay), by either existing underground storm drain
systems or conveyance channels whose bed and bank are concrete-lined all the way from the point
of discharge to the enclosed embayment, are exempt” (see the attached excerpt). However, the
following conditions apply:
1. The outfall must not be located within a wildlife refuge or reserve area.
2. A properly sized energy dissipation system must be provided to mitigate outlet discharge
velocity from the direct discharge to the enclosed embayment for the ultimate condition
peak design flow of the direct discharge.
3. The invert elevation of the direct discharge conveyance system (at the point of discharge
to the enclosed embayment) should be equal to or below the mean high tide water surface
elevation at the point of discharge.
The project runoff will be conveyed by existing concrete swales, concrete curbs, concrete gutters,
storm drains, culverts, or concrete channels to San Diego Bay, so the project directly discharges
to an enclosed embayment. Furthermore, the three conditions are met. For condition 1, the
approved Chula Vista Bayfront Master Plan’s approved Land Use Plan is attached along with an
ecological map. These exhibits identify refuge and reserve areas within San Diego Bay. Neither a
refuge nor a reserve exist at the project’s outfall to San Diego Bay. For condition 2, the concrete-
lined channel that discharges into San Diego Bay is a major public drainage facility, so must have
proper energy dissipation. A site inspection did not reveal signs of erosion at the outlet. For
condition 3, the attached as-built plan shows that the concrete channel flow line at the railroad
crossing is elevation 1.7 feet USGS vertical datum. The concrete channel outlet is downstream of
this location, so the outlet flow line will be slightly lower. San Diego Regional Standard Drawing
M-12 indicates that mean high water is at elevation 2.01 feet USGS (attached). Therefore, the
invert of the outlet to San Diego Bay is below mean high water.
Based on this information, the 310-316 K Street redevelopment project meets the city of Chula
Vista’s criteria for a hydromodification exemption.
Sincerely,
Wayne W. Chang, M.S., P.E.
Attachments
Chapter 1: Policies and Procedural Requirements
BMP Design Manual
December 2015 1-14
Figure 1-2, Node 3 – As allowed by the MS4 Permit, projects discharging directly to enclosed
embayments (e.g., San Diego Bay or Mission Bay), by either existing underground storm drain
systems or conveyance channels whose bed and bank are concrete-lined all the way from the
point of discharge to the enclosed embayment, are exempt.
o This exemption is subject to the following conditions:
a) The outfall must not be located within a wildlife refuge or reserve area (e.g., Kendall -
Frost Mission Bay Marsh Reserve, San Diego Bay National Wildlife Refuge, San
Diego National Wildlife Refuge),
b) A properly sized energy dissipation system must be provided to mitigate outlet
discharge velocity from the direct discharge to the enclosed embayment for the
ultimate condition peak design flow of the direct discharge,
c) The invert elevation of the direct discharge conveyance system (at the point of
discharge to the enclosed embayment) should be equal to or below the mean high
tide water surface elevation at the point of discharge, unless the outfall discharges to
a quay or other non-erodible shore protection.
Figure 1-2, Node 4 – As allowed by the MS4 Permit, projects discharging directly to a water
storage reservoir or lake, by either existing underground storm drain systems or conveyance
channels, whose bed and bank are concrete-lined all the way from the point of discharge to the
water storage reservoir or lake, are exempt.
o This exemption is subject to the following conditions:
a) A properly sized energy dissipation system must be provided in accordance with City
design standards to mitigate outlet discharge velocity from the direct discharge to the
water storage reservoir or lake for the ultimate condition peak design flow of the
direct discharge,
b) The invert elevation of the direct discharge conveyance system (at the point of
discharge to the water storage reservoir or lake) should be equal to or below the
lowest normal operating water surface elevation at the point of discharge, unless the
outfall discharges to a quay or other non-erodible shore protection. Normal
operating water surface elevation may vary by season; contact the reservoir operator
to determine the elevation. For cases in which the direct discharge conveyance
system outlet invert elevation is above the lowest normal operating water surface
elevation but below the reservoir spillway elevation, additional analysis is required to
determine if energy dissipation should be extended between the conveyance system
outlet and the elevation associated with the lowest normal operating water surface
level.
c) No exemption may be granted for conveyance system outlet invert elevations located
above the reservoir spillway elevation.
Figure 1-2, Node 5 – As allowed by the MS4 Permit, projects discharging directly to an area
identified as appropriate for an exemption in the WMAA for the watershed in which the projec t
resides, by either existing underground storm drain systems or conveyance channels whose bed
and bank are concrete-lined all the way from the point of discharge to the designated area, are
exempt. Consult the WMAA within the WQIP for the watershed in whi ch the project resides to
40621
40620
40580
40570
40560
40550 40540
40530
40500
40481
40480
40510
40360
40351
40350
40310
40300
40290
40281
40190
40180
40170
40140
40131
40130
40160
40030
40200
40120
40110
40100
40040
40090
40080
40070
40060
40051
40050
40260
40220
40270
40250
40240
40231
40230
30030
30020
30010
30001
30000
1490
11481
50001
50000
11370
11361
11360
40020
10790
10751
10750
40010
40520
40490
40370
40280
5 4"
6 6"
4
'
x
1
.
5
'
2 -33 "
1
8
"
30"
5 4"
4
8
"
4
2
"
3
6
"
2 7 "
4 8 "
4
1
8
"
2 7 "
3
0
"
3
0
"
3 6 "
33"
48"
3
3
"
5 4 "
4
2
"4
8
"
3 6"
54 "
3 6"
3 3 "
33"
3 3"
4
2
"
4
2
"
3
0
"
3 6"
3
6
"
27 "
3
6
"
2 7 "
54 "
3 'x 4 '
3 'x4'4 'x 2'
33 "
4
2
"
3
6
"
3
0
"
3
6
"
48.8ac
36.0ac
31.9ac
28.8ac
25.1ac
25.1ac
23.7ac
23.3ac
22.5ac
18.1ac
17.2ac
15.9ac
15.3ac
14.2ac
14.1ac
13.9ac
13.4ac
13.1ac
12.1ac
11.3ac
11.3ac
8.6ac
8.5ac8.4ac
8.4ac
8.3ac
7.7ac
7.6ac
7.5ac
7.0ac
6.1ac
5.7ac
5.1ac
4.4ac
4.3ac
4.0ac
3.4ac
2.9ac
2.7ac
2.5ac
1.9ac
0.3ac
0.3ac
0.3ac
0.2ac
0.2ac
0.2ac
0.1ac
0.1ac
0.1ac
0.1ac
0.1ac
0.1ac
0
3
R
D
A
V
B
R
O
A
D
W
A
Y
F29F29
F9F9
F9F9
F9F9
F28F28
F3F3
F30F30
Central
Telegraph Canyon
Judson
L ST
I ST
KING
S
T
JST
MOSS ST
T
H
I
R
D
A
V
K ST
A
S
H
A
V
B
R
O
A
D
W
A
Y
W E S T B Y S T
D
A
T
E
A
V
N IC K MAN
S
T
B
E
E
C
H
A
V
C
E
D
A
R
A
V
SECOND AV
D
E
L
M
A
R
A
V
H
I
L
L
T
O
P
D
R
F
I
G
A
V
M ILL A NCT
J
P
L
AR IZON A ST
E
L
D
E
R
A
V
E
P
A
R
K
L
N
E
L
M
A
V
A
L
P
I
N
E
A
V
WYK ES
S
T
C
H
U
R
C
H
A
V
S IE RR AWY
J AMES
C
T
CLAR IS SST
WE LTON
S
T
S AN
M
I
G
UEL
D
R
KI TTIWAKE
L N
M
A
D
I
S
O
N
A
V
R
I
V
E
R
L
A
W
N
A
V
G
U
A
V
A
A
V
T
W
I
N
O
A
K
S
A
V
B
R
I
G
H
T
W
O
O
D
A
V
F
O
U
R
T
H
A
V
NAP LES ST
GLOVER
P L
H A LS E YST
EMERSO
N
S
T
F
A
I
R
W
A
Y
C
T
G A R D EN
P
L
JA M ES S T
KE AR NEY
S
T
J
E
F
F
E
R
S
O
N
A
V
JACQUELINE WY
P ETEO
C
T
VALLECIT
O
W
Y
COUNTRYCLUB
D
R
CRE ST ED
B
U
T
TE
S
T
C
L
U
B
V
I
E
W
T
E
W
I
D
G
E
O
N
L
N
J ASON P L
K
A
R
E
N
W
Y
KST
L ST
S ANMIG U EL DR
L ST
T
H
I
R
D
A
V
4
0
50
6
0
70
80
90
1 10
1
2
0
1 0 0
140
1
7
0
1
30
15
0
180
160
140
5
0
90
16
0
1
0
0
70
70
100
11
0
60
90
90
5
0
80
120
140
80
1
2
0
1 20
80
70
9 0
80
12 0
1
1
0
180
8
0
5 0
80
40
6
0
90
10 0
60
80
7
0
120
150
1 1 0
6 0
1
3
0
150
12
0
5
0
1
7
0
11 0
80
50
9
0
110
160
140
70
40
12070
50
60
150
1
4
0
9
0
70
110
1
5
0
40
70
7
0
8
0
6 0
8
0
110
5
0
9 0
1
1
0
15 0
8
0
10 0
6
0
5
0
130
1
2
0
1
5
0
1
1
0
1
0
0
100
50
90
5
0
1
0
0
1
1
0
10
0 1 1 0
9 0
6
0
1
0
0
1 3 0
6 0
120
40
150
80
9 0
60
60
110
100
8
0
1
0
0
130
90
60
110
1
4
0
100
9
0
6
0
80
40
8
0
130
6
0
4
0
1
4
0
140
70
100
12 0
70
80
8
0
50
1
0
0
4 0
14
0
7
0
100
80
60
80
4
0
5
0
5
0
100
70
160
60
1 1 0
110
1 3 0
9
0
140
1
4
0
70
5
0
40
90
110
7
0
1
0
0
70
70
1
0
0
1 4 0
1 0 0
120
5
0
90
1
1
0
5 0
50
1 5 0
6 0
90
1 6 0
16
0
1
5
0
1
2
0
130
11
0
130
4
0
1
3
0
9
0
120
100
140
90
100
4
0
90
60
8
0
40
80
100
50
120
14
0
12
0
60
9
0
11 0
7
0
120
13
0
40
9
0
1 2 0
1 1 0
1
30
160
110
4 0
130
8 0
7
0
90
6
0
8 0
1
0
0
90
80
9 0
110
5 0
1
1
0
6 0
1 1 0
150
13 0
90
160
110
130
70
1
2
0
70
6 0
170
60
1
3
0
40
5
0
50
9
0
90
100
80
90
4 0
5
0
70
80
1
1
0
1
4
0
60
70
Chula Vista
Drainage
Master Plan
Central
Drainage
Basin
1 inch equals 200 feet
Z:\Projects\IS\ChulaVistaMP\Stormwater\mxd\Mapooks\Version9\CentralGRID\Preferred Alternative\CentralGRID.mxd 200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000
Feet
Feb 08, 2005
Aerial Photo: January 2003
Map Created:
Current Tile: 5
ª
GLOBAL INDICATOR?À
?j
%&s(
!"^$
3
5
21
4
Legend
Inlet
CMP Not Modeled
Basin Area
Initial Area Boundary
Minor Basin Boundary
Major Basin Boundary
1.0 ac
Model Node
10000
Stormdrain Not Modeled
Stormdrain Not Modeled
Flowlines Unknown
Channel or Ditch
Flooded AreasF1
Outlet
Manhole
City Boundary
CMP Not Modeled
Flowlines Unknown
24"CMP Modeled
Stormdrain Modeled
24"
Existing Pipe Size
24"
50100
50090
50070
50050
40640
40630
40610
40600
40580
4
40470
40460
40450
40440
40430
40420
40400
40390 40380
40340
40330
30050
30040
30030
30020
3001
30060
11570
11540
11530
11520
11510
11500 11490
11340
11330
11325
1132011660
50040
50030
50020
50010
50001
50000
11345
11350
11470
11440
50080
50060
40590
40410
40370
60030
60040
6000060001
60010
60100
60090
60081
60080
60070
60060
60051
60050
11700
11690
11680
11670
11720
11711
11710
42
3'
x
3
'
2 -33 "
2-4'x4
'
3 0 "
36"
36"
4
5
"
3
6
"
39"
4 8"
30 "
5
4
"
3 3"
3
6
"
2-57"
2
-
5
7
"
6 6"
36
"
3'
x
3
'
30"
3
0
"6
6
"
66"
6 6 "
3 3 "
2 -33"
4'
x
5
'
2-4
5"60"
2-4'x4
'
30"
3 0 "
1
8
"
48"
3
6
"
2 -33"
36"
3'
x
3
'
30"
3 0"
2-33"
36"
23
14.2ac
13.3ac
9.9ac
11.2ac
9.1ac
10.5ac
8.3ac
8.3ac
8.2ac
7.5ac
7.4ac
6.2ac
6.0ac
6.0ac
5.5ac
5.4ac
5.1ac
5.1ac
4.8ac
4.4ac
4.2ac
3.6ac
3.5ac
3.5ac
3.4ac
3.4ac
3.3ac
3.2ac
2.7ac
2.6ac
2.6ac2.4ac
0.1ac
132.6ac
106.8ac
54.4ac
21.8ac
8.5ac
6.8ac
4.8ac
4.5ac
0.4ac
0.3ac
0.2ac
0.1ac
Drainage Basin Boundaries West
of Interstate 5 are Approximate
Drainage Basin Boundaries West
of Interstate 5 are Approximate
Q 50-YR, EXIST
= 4180 cfs
Q 50-YR, GEN PLAN
= 4180 cfs
Q 100-YR, PREF ALT
=4803cfs
Q 50-YR, PREF ALT
= 4384 cfs
Q100-YR, EXIST
=4798cfs
Q 100-YR, GEN PLAN
=4801cfs
Q 50-YR, EXIST
=6cfs
Q 50-YR, GEN PLAN
=6cfs
Q 50-YR, PREF ALT
=6cfs
Q 50-YR, EXIST
=32cfs
Q 50-YR, GEN PLAN
=32cfs
Q 50-YR, PREF ALT
=32cfs
Q 50-YR, EXIST
=365cfs
Q 50-YR, GEN PLAN
=365cfs
Q 50-YR, PREF ALT
=365cfs
Q 50-YR, EXIST
=131cfs
Q 50-YR, GEN PLAN
=131cfs
Q 50-YR, PREF ALT
=131cfs
HST
B
R
O
A
D
W
A
Y
F6F6
Central
Telegraph Canyon
Telegraph Canyon
Southwest
BAY
B
L
M
A
R
I
N
A
P
K
W
Y
M
A
R
I
N
A
W
Y
O
A
K
L
A
W
N
A
V
J
E
F
F
E
R
S
O
N
A
V
Q
U
A
Y
A
V
S
A
N
D
P
I
P
E
R
W
Y
I
-
5
F
R
E
E
W
A
Y
R
A
M
P
W
E
S
T
M
A
N
O
R
D
R
C
O
L
O
R
A
D
O
A
V
W
O
O
D
L
A
W
N
A
V
B A Y S IDE
P
KWY
I
E
S
P
L
A
N
A
D
E
0
3
0
1 0
2 0
40
5
0
30
20
2
0
40
50
10
1
0
30
10
10
10
0
0
3
0
1 0
4 0
0
2
0
20
10
2
0
10
2
0
10
1
0
40
3
0
3
0
2
0
10
30
10
10
10
40
10
20
10
0
1
0
20
3 0
3
0
10
0
4
0
30
0
1
0
1
0
10
20
20
10
20
10
10
0
10
1
0
2 0
3
0
30
3
0
10
4 0
2
0
2
0
5
0
2
0
10
0
10
10
10
2
0
4
0
0
20
0
10
20
2
0
3
0
1
0
3
0
0
0
10
10
40
3
0
10
0
20
30
4
0
1
0
30
30 30
1 0
2
0
20
0
10
10
20
2
0
30
4
0
1 0
4 0
2
0
1 0
0
0
1 0
10
3 0
3
0
10
40
10
1
0
30
0
10
50
30
0
3
0
10
3
0
2
0
20
20
20
20
0
1
0
1 0
10
10
1
0
10
3 0
10
0
2
0
1
0
20
2
0
10
3
0
40
40
1
0
10
2
0
1
0
0
10
20
0
20
30
2
0
10
10
3
0
4
0
40
4
0
2
0
10
4
0
0
3
0
2
0
20
10
3
0
2
0
0
10
30
2
0
20
10
30
3
0
1
0
2
0
3
0
2
0
20
10
2
0
10
1
0
1 0
1
0
20
1
0
1
0
20
2 0
3
0
10
2
0
1
0
2
0
20
10
3 0
1
0
20
5
0
1
0
0
2
0
1
0
1
0
1 0
3
0
1 0
20
10
1
0
20
10
10
0
0
3
0
0
30
1
0
4
0
4
0
2
0
1
0
50
10
2
0
2
0
3
0
10
1
0
20
30
30
0
20
30
2
0
20
3
0
0
3
0
3
0
10
1
0
0
10
1
0
2
0
0
0
3
0
1
0
10
1
0
20
3
0
3
0
1
0
1 0
1
0
20
3
0
20
20
Chula Vista
Drainage
Master Plan
Central
Drainage
Basin
1 inch equals 200 feet
Z:\Projects\IS\ChulaVistaMP\Stormwater\mxd\Mapooks\Version9\CentralGRID\Preferred Alternative\CentralGRID.mxd 200 0 200 400 600 800 1,000 1,200 1,400 1,600 1,800 2,000
Feet
Feb 08, 2005
Aerial Photo: January 2003
Map Created:
Current Tile: 4
ª
GLOBAL INDICATOR?À
?j
%&s(
!"^$
3
5
21
4
Legend
Inlet
CMP Not Modeled
Basin Area
Initial Area Boundary
Minor Basin Boundary
Major Basin Boundary
1.0 ac
Model Node
10000
Stormdrain Not Modeled
Stormdrain Not Modeled
Flowlines Unknown
Channel or Ditch
Flooded AreasF1
Outlet
Manhole
City Boundary
CMP Not Modeled
Flowlines Unknown
24"CMP Modeled
Stormdrain Modeled
24"
Existing Pipe Size
24"
Nature Center
parking
Harbor and Marinas
Chula Vista Bayfront Master Plan Illustrative
Locally and State-Approved Land Use Plan by
City of Chula Vista and Port of San Diego
Park
24 ac
Buffer:
25 ac
RV Park
Industrial Business Park
Industrial
Business Park
North
Buffer:
41.1 ac
Signature Park:
21 ac
Park
Seasonal
Wetland:
14.7 ac
Office
Mixed Use/ Commercial
Resort
Conference Center
RV Park/
Campground Hotel/
Cultural Retail
Retail (around harbor)
Residential
Hotel/Office
Pa
r
k
Pa
r
k
E
S
T
R
E
E
T
F
S
T
R
E
E
T
H
S
T
R
E
E
T
J
S
T
R
E
E
T
v.01/02/13
Interstate 5
Wildlife
Reserve
Sweetwater
Marsh
South Bay
Salt Ponds
Chula Vista
Nature Center
Park
Harbor Park:
25 ac
Park
Public/
Quasi-Public
Mixed Use/
Commercial/
Parking Structure
Existing
Boat Yard
•RV Park/ Campground
•25 ft max height
•120,000 SF
• 44 ft max height
•120,000 SF
•45 ft max height
•Portion of 2,850 hotel rooms
allowed between H-3 + H-23
•415,000 SF max conference space
•240 ft max hotel structure height
•120 ft max conference center height
•Portion of 2,850 hotel rooms
allowed between H-3 + H-23
•300 ft max height
•200,000 SF (cultural/retail)
•65 ft max height
•225,000 SF
•25 ft max height
•100,000 SF mixed use/commercial
•3,000 space parking garage
•155 ft max height
•1,500 residential units
•25 ft - 45 ft podium heights
•70 ft – 200 ft tower heights
•15,000 SF retail ground floor
•420,000 SF office
•250 rooms
•130 ft max height
•9,500 SF
•30 ft max height
•237 RV spaces
•25 ft max height
San Diego Bay
L
S
T
R
E
E
T
I-5
Resort
Conference
Center
Resort
Conference
Center
Seasonal
Wetland
Seasonal
Wetland
RV Park/
Campground
RV Park/
Campground
Nature
Center
parking
Nature
Center
parking
Mixed Use/
Commercial
Mixed Use/
Commercial
OfficeOffice
Existing
Boat Yard
Existing
Boat Yard
Hotel/Cultural/
Retail
Hotel/Cultural/
Retail
Hotel/OfficeHotel/Office
Harbor and MarinasHarbor and Marinas
ResidentialResidential
Retail (around harbor)Retail (around harbor)
ParkPark
RV ParkRV Park
Industrial Business ParkIndustrial Business Park
Industrial
Business Park
Industrial
Business Park
BufferBuffer
Signature
Park
Signature
Park
ParkPark
ParkPark
ParkPark
ParkPark
E
S
T
R
E
E
T
E
S
T
R
E
E
T
F
S
T
R
E
E
T
F
S
T
R
E
E
T
H
S
T
R
E
E
T
H
S
T
R
E
E
T
J
S
T
R
E
E
T
J
S
T
R
E
E
T
I-5I-5
BufferBuffer
Emory
Cove
Wildlife
Reserve
Emory
Cove
Wildlife
Reserve
Chula Vista Bayfront Master Plan BoundaryChula Vista Bayfront Master Plan Boundary
Mean High Tide LineMean High Tide Line
Protected Wildlife AreasProtected Wildlife Areas
South Bay Unit of the
San Diego National
Wildlife Refuge
South Bay Unit of the
San Diego National
Wildlife Refuge
Silver
Strand
Beach
Silver
Strand
Beach
Sweetwater
National
Wildlife
Refuge
Sweetwater
National
Wildlife
Refuge
Sw
e
e
t
w
a
t
e
r
R
i
v
e
r
M
o
u
t
h
Sw
e
e
t
w
a
t
e
r
R
i
v
e
r
M
o
u
t
h
Mixed Use/
Commercial/
Parking
Structure
Mixed Use/
Commercial/
Parking
Structure
Public/
Quasi-Public
Public/
Quasi-Public
National
Wildlife
Refuge
Pond 20Pond 20
Poseidon
Restoration
Poseidon
Restoration
Sweetwater Tidal FlatsSweetwater Tidal Flats
J St. MarshJ St. Marsh
Future Coop.
Management Area
Future Coop.
Management Area Chula
Vista
Wildlife
Reserve
Chula
Vista
Wildlife
Reserve
California
Least Tern
Nesting
Sites
California
Least Tern
Nesting
Sites
South Bay Unit of the
San Diego National
Wildlife Refuge
South Bay Unit of the
San Diego National
Wildlife Refuge
Wetlands
Restoration
Wetlands
Restoration
Usable Parks and Open SpaceUsable Parks and Open Space
Page intentionally left blank for double‐sided printing
ATTACHMENT 3
Structural BMP Maintenance Information
This is the cover sheet for Attachment 3.
Page intentionally left blank for double‐sided printing
Indicate which items are included behind this cover sheet:
Attachment
Sequence Contents Checklist
Attachment 3a Structural BMP Maintenance Thresholds
and Actions (Required)
☒ Included
See Structural BMP Maintenance
Information Checklist on the back of this
Attachment cover sheet.
Attachment 3b Draft Maintenance Agreement (when
applicable)
☐ Included
☒ Not Applicable
Use this checklist to ensure the required information has been included in the Structural BMP
Maintenance Information Attachment:
☒ Preliminary Design / Planning / CEQA level submittal:
Attachment 3a must identify:
☒ Typical maintenance indicators and actions for proposed structural BMP(s) based on Section
7.7 of the BMP Design Manual
Attachment 3b is not required for preliminary design / planning / CEQA level submittal.
☐ Final Design level submittal:
Attachment 3a must identify:
☐ Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based
on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed
components of the structural BMP(s)
☐ 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
Attachment 3b: For private entity operation and maintenance, Attachment 3b shall include a draft
maintenance agreement in the local jurisdiction's standard format (PDP applicant to contact the City
Engineer to obtain the current maintenance agreement forms).
Page intentionally left blank for double‐sided printing
Modular Wetlands System™ Linear
Biofiltration
Comprehensive
Stormwater
Solutions
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 (MWS Linear) represents
a pioneering breakthrough in stormwater
technology as the only biofiltration system
to utilize patented horizontal flow, allowing
for a smaller footprint and higher treatment
capacity. While most biofilters use little
or no pretreatment, the MWS Linear
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,
in turn reducing maintenance costs and
improving performance.
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 our cities grow and develop,
these natural wetlands have perished under
countless roads, rooftops, and parking lots.
Plant A Wetland
Without natural wetlands, our cities are
deprived of water purification, flood control,
and land stability. Modular Wetlands and the
MWS Linear re-establish nature’s presence
and rejuvenate waterways in urban areas.
PERFORMANCE
The MWS Linear continues to outperform other treatment methods with superior pollutant removal for
TSS, heavy metals, nutrients, hydrocarbons, and bacteria. Since 2007 the MWS Linear has been field
tested on numerous sites across the country. With its advanced pretreatment chamber and innovative
horizontal flow biofilter, the system is able to effectively remove pollutants through a combination of
physical, chemical, and biological filtration processes. With the same biological processes found in natural
wetlands, the MWS Linear harnesses nature’s ability to process, transform, and remove even the most
harmful pollutants.
APPROVALS
The MWS 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.
RHODE ISLAND DEM APPROVED
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.
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.
MARYLAND DEPARTMENT OF THE ENVIRONMENT
APPROVED
Granted Environmental Site Design (ESD) status for new construction, redevelopment,
and retrofitting when designed in accordance with the design manual.
DEQ 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.
VA
WASHINGTON STATE 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.
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
OPERATION
The MWS 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, and
minimizes maintenance. Figure 1 and Figure 2 illustrate the invaluable benefits of horizontal
flow and the multiple treatment stages.
Cartridge Housing
Pre-filter Cartridge
Curb Inlet
Individual Media Filters
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
PRETREATMENT1 1
2
1
2Vertical Underdrain
Manifold
BioMediaGREEN™
WetlandMEDIA™
Figure 1
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
BIOFILTRATION2
DISCHARGE3
PERIMETER
V
O
I
D
A
R
E
A
3
4
3Flow Control
RiserDraindown Line
Outlet Pipe
CONFIGURATIONS
The MWS 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 MWS Linear 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 MWS Linear 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 MWS Linear 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 MWS Linear 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.
This simple yet innovative diversion trough can be
installed in existing or new curb and grate inlets to
divert the first flush to the MWS Linear 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 MWS
Linear to be installed anywhere space is available.
DVERT LOW FLOW DIVERSION
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
FLOW-BASED
The MWS Linear can be used in stand-alone applications to meet treatment flow requirements. Since the
MWS Linear 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.
SPECIFICATIONS
VOLUME-BASED
Many states require treatment of a water quality volume and do not offer the option of flow-based design.
The MWS Linear and its unique horizontal flow makes it the only biofilter that can be used in volume-based
design installed downstream of ponds, detention basins, and underground storage systems.
MODEL #TREATMENT CAPACITY (cu. ft.)
@ 24-HOUR DRAINDOWN
TREATMENT CAPACITY (cu. ft.)
@ 48-HOUR DRAINDOWN
MWS-L-4-4 1140 2280
MWS-L-4-6 1600 3200
MWS-L-4-8 2518 5036
MWS-L-4-13 3131 6261
MWS-L-4-15 3811 7623
MWS-L-4-17 4492 8984
MWS-L-4-19 5172 10345
MWS-L-4-21 5853 11706
MWS-L-6-8 3191 6382
MWS-L-8-8 5036 10072
MWS-L-8-12 7554 15109
MWS-L-8-16 10073 20145
MWS-L-8-20 12560 25120
MWS-L-8-24 15108 30216
SPECIFICATIONS
INDUSTRIAL
Many states enforce strict regulations for discharges
from industrial sites. The MWS Linear 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
MWS Linear’s 4 ft. standard planter width allows for
easy integration into parking lot islands and other
landscape medians.
MIXED USE
The MWS Linear 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 MWS Linear. The system
can be used in both decentralized LID design and
cost-effective end-of-the-line configurations.
STREETS
Street applications can be challenging due to limited
space. The MWS Linear is very adaptable, and it
offers the smallest footprint to work around the
constraints of existing utilities on retrofit projects.
COMMERCIAL
Compared to bioretention systems, the MWS
Linear can treat far more area in less space, meeting
treatment and volume control requirements.
APPLICATIONS
The MWS 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 applications - treating
rooftops, streetscapes, parking lots, and industrial sites.
More applications include:
• Agriculture • Reuse • Low Impact Development • Waste Water
PLANT SELECTION
Abundant plants, trees, and grasses bring value and an aesthetic benefit
to any urban setting, but those in the MWS 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 MWS Linear,
giving the plants more contact time so that pollutants are more successfully decomposed, volatilized, and
incorporated into the biomass of the MWS Linear’s micro/macro flora and fauna.
A wide range of plants are suitable for use in the MWS Linear, but selections vary by location and climate.
View suitable plants by visiting biocleanenvironmental.com/plants.
INSTALLATION MAINTENANCE
The MWS Linear 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 are available to supervise
installations and provide technical support.
Reduce your maintenance costs, man hours,
and materials with the MWS Linear. Unlike other
biofiltration systems that provide no pretreatment,
the MWS Linear 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.More applications include:
• Agriculture • Reuse • Low Impact Development • Waste Water
072318R1
398 Via El Centro
Oceanside, CA 92058
855.566.3938
stormwater@forterrabp.com
biocleanenvironmental.com
A Forterra Company
www.modularwetlands.com
Maintenance Guidelines for
Modular Wetland System - Linear
Maintenance Summary
o Remove Trash from Screening Device – average maintenance interval is 6 to 12 months.
(5 minute average service time).
o Remove Sediment from Separation Chamber – average maintenance interval is 12 to 24 months.
(10 minute average service time).
o Replace Cartridge Filter Media – average maintenance interval 12 to 24 months.
(10-15 minute per cartridge average service time).
o Replace Drain Down Filter Media – average maintenance interval is 12 to 24 months.
(5 minute average service time).
o Trim Vegetation – average maintenance interval is 6 to 12 months.
(Service time varies).
System Diagram
Access to screening device, separation
chamber and cartridge filter
Access to drain
down filter
Pre-Treatment
Chamber
Biofiltration Chamber
Discharge
Chamber
Outflow
Pipe
Inflow Pipe
(optional)
www.modularwetlands.com
Maintenance Procedures
Screening Device
1. Remove grate or manhole cover to gain access to the screening device in the Pre-
Treatment Chamber. Vault type units do not have screening device. Maintenance
can be performed without entry.
2. Remove all pollutants collected by the screening device. Removal can be done
manually or with the use of a vacuum truck. The hose of the vacuum truck will not
damage the screening device.
3. Screening device can easily be removed from the Pre-Treatment Chamber to gain
access to separation chamber and media filters below. Replace grate or manhole
cover when completed.
Separation Chamber
1. Perform maintenance procedures of screening device listed above before
maintaining the separation chamber.
2. With a pressure washer spray down pollutants accumulated on walls and cartridge
filters.
3. Vacuum out Separation Chamber and remove all accumulated pollutants. Replace
screening device, grate or manhole cover when completed.
Cartridge Filters
1. Perform maintenance procedures on screening device and separation chamber
before maintaining cartridge filters.
2. Enter separation chamber.
3. Unscrew the two bolts holding the lid on each cartridge filter and remove lid.
4. Remove each of 4 to 8 media cages holding the media in place.
5. Spray down the cartridge filter to remove any accumulated pollutants.
6. Vacuum out old media and accumulated pollutants.
7. Reinstall media cages and fill with new media from manufacturer or outside
supplier. Manufacturer will provide specification of media and sources to purchase.
8. Replace the lid and tighten down bolts. Replace screening device, grate or
manhole cover when completed.
Drain Down Filter
1. Remove hatch or manhole cover over discharge chamber and enter chamber.
2. Unlock and lift drain down filter housing and remove old media block. Replace with
new media block. Lower drain down filter housing and lock into place.
3. Exit chamber and replace hatch or manhole cover.
www.modularwetlands.com
Maintenance 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 require irrigation.
www.modularwetlands.com
Maintenance Procedure Illustration
Screening Device
The screening device is located directly
under the manhole or grate over the
Pre-Treatment Chamber. It’s mounted
directly underneath for easy access
and cleaning. Device can be cleaned by
hand or with a vacuum truck.
Separation Chamber
The separation chamber is located
directly beneath the screening device.
It can be quickly cleaned using a
vacuum truck or by hand. A pressure
washer is useful to assist in the
cleaning process.
www.modularwetlands.com
Cartridge Filters
The cartridge filters are located in the
Pre-Treatment chamber connected to
the wall adjacent to the biofiltration
chamber. The cartridges have
removable tops to access the
individual media filters. Once the
cartridge is open media can be
easily removed and replaced by hand
or a vacuum truck.
Drain Down Filter
The drain down filter is located in the
Discharge Chamber. The drain filter
unlocks from the wall mount and hinges
up. Remove filter block and replace with
new block.
www.modularwetlands.com
Trim Vegetation
Vegetation should be maintained in the
same manner as surrounding vegetation
and trimmed as needed. No fertilizer shall
be used on the plants. Irrigation
per the recommendation of the
manufacturer and or landscape
architect. Different types of vegetation
requires different amounts of
irrigation.
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
Modular
PART
01.01.0
The pur
Flow We
contami
enginee
regardin
with this
01.02.0
Modular
including
pretreat
peripher
containi
establish
flows ho
orifice co
01.03.0
The man
producti
which ha
the draw
Services
Environm
Subsurface Fl
Mod
T 1 – GEN
00 Purpose
pose of this s
etland System
nated water s
ers, contractor
ng materials, m
s specification
00 Descrip
r Subsurface
g dry weather
ment chambe
ral void area a
ng a sorptive
hment media
orizontally in s
ontrol structu
00 Manufa
nufacturer of
on of system
ave a history
wings, the MS
s, Inc., or Mod
mental Servic
Corporate He
Bio Clean En
2972 San Lu
Oceanside, C
Phone: (760)
Fax: (760) 43
www.biocleanen
Corporate He
Modular Wet
P.O. Box 869
Oceanside, C
Phone: (760)
www.modularwe
ow Wetland Sy
dular Su
NERAL
e
specification is
ms used for b
sources. It is
rs, plumbers,
manufacture
n.
ption
Flow Wetland
r flows. The M
er containing
and a central
media mix w
, and a discha
series through
re.
acturer
the MSFWS
s developed f
of successfu
SFWS(s) shall
dular Wetland
ces Inc., and
eadquarters:
nvironmental S
is Rey Road
CA 92058
) 433-7640
33-3176
nvironmental.net
eadquarters:
tland Systems
9
CA 92049
) 433-7650
etlands.net
ystem Page
Section
ubsurfac
s to establish
iofiltration of s
intended to s
installers, ins
and installatio
d Systems (M
MSFWS is a
filtration cartr
ized and vert
which does no
arge chambe
h the pretreat
shall be one t
for the treatm
l production, a
l be a filter de
d Systems, In
Modular Wetl
Service, Inc.
s, Inc.
e 1 of 6
n [_____
ce Flow
generally acc
stormwater ru
serve as a gu
spectors, age
on; and to pro
MSFWS) are u
pre-engineere
ridges, a horiz
ically extendi
t contain any
r containing a
ment chambe
that is regular
ment of stormw
acceptable to
evice Manufac
nc., or assigne
land Systems
____]
Wetland
ceptable crite
unoff including
ide to produc
ncies and use
ovide for iden
used for filtrat
ed biofiltration
zontal flow bio
ng underdrain
organic mate
an orifice con
er cartridges,
rly engaged i
water runoff fo
o the enginee
ctured by Bio
ed distributors
s, Inc., can be
d System
eria for Modul
g dry weathe
cers, distributo
ers; to promo
ntification of d
tion of stormw
n system com
ofiltration cha
n, the biofiltra
erial and a lay
trol structure
biofiltration c
n the enginee
or at least (10
r of work. In
o Clean Enviro
s or licensees
e reached at:
m
lar Subsurfac
r flows and ot
ors, architects
ote understan
evices compl
water runoff
mposed of a
amber with a
ation chamber
yer of plant
. Treated wat
chamber and
ering design a
0) years, and
accordance w
onmental
s. Bio Clean
ce
ther
s,
ding
ying
r
ter
and
with
Modular S
01.04.00
0
0
0
01.05.00
0
0
01.06.00
ASTM
ASTM
ASTM
ASTM
ASTM
ASTM
ASTM D
ASTM D
ASTM D
AASHTO
01
AASHTO
AASHTO
AASHTO
AASHTO
AASHTO
AASHTO
ubsurface Flow
0 Submitta
1.04.01
1.04.02
1.04.03
0 Work Inc
1.05.01
1.05.02
0 Referenc
C 29 Sta
C 88 C 8
Sul
C131 C 1
Co
C 136 C 1
C 330 C 3
D 698 Tes
Effo
D 1621 10
D 1777 AS
Ma
D 4716 Sta
and
O T 99-
1
Sta
(5.5
O T 104 Sta
or M
O T 260 Sta
and
O T 288 Sta
O T 289 Sta
O T 291 Sta
Soi
O T 290 T 2
Co
w Wetland Sys
als
Shop drawi
consulting e
Shop drawi
sequence f
Inspection a
cluded
Specificatio
Manufactur
Pre
Co
Bio
Flo
ce Standard
andard Test M
88 Standard T
lfate or Magn
131 Standard
arse Aggrega
136 Standard
330 Standard
st Method for
ort (12,400 ft.
Standard Tes
TM D1777 - 9
aterials
andard Test M
d Hydraulic T
andard Metho
5-lb) Rammer
andard Metho
Magnesium S
andard Metho
d Concrete R
andard Metho
andard Metho
andard Metho
il
290 Standard
ntent in Soil
stem Page
ings are to be
engineer.
ings are to de
for installation
System
Interior
Any acc
and maintena
on requiremen
rer to supply c
etreatment ch
ncrete Struct
ofiltration cham
ow control disc
ds
Method for Un
Test Method f
esium Sulfate
Test Method
ates by Abras
Test Method
Specification
Laboratory C
.-lbf/ft3 (600 k
st Method for
96(2007) Stan
Method for De
ransmissivity
od of Test for
r and a 305-m
od of Test for
Sulfate
od of Test for
aw Materials.
od of Test for
od of Test for
od of Test for
Method of Te
2 of 6
e submitted w
etail the MSFW
n, including:
configuration
components
cessory equip
ance docume
nts for installa
components o
hamber compo
ure(s)
mber compon
charge struct
nit Weight and
for Soundnes
e
for Resistan
sion and Impa
for Sieve An
n for Lightweig
Compaction C
kN-m/m3)
Compressive
ndard Test M
etermining the
of a Geosynt
Moisture-Den
mm (12-in) Dr
Soundness o
Sampling and
.
Determining M
Determining p
Determining W
est for Determ
with each orde
WS and all co
n with primary
pment called o
entation subm
ation of MSFW
of the MSFW
onents (pre-a
nents (pre-ass
ture (pre-asse
d Voids in Agg
ss of Aggrega
ce to Degrad
act in the Los
nalysis of Fine
ght Aggregate
Characteristics
e Properties O
Method for Thi
e (In-plane) F
thetic Using a
nsity Relation
rop
of Aggregate b
d Testing for
Minimum Lab
ph of Soil for
Water Soluble
mining Water
er to the contr
omponents re
y dimensions
out on shop d
mitted upon req
WS.
WS(s):
assembled)
sembled)
embled)
gregate
tes by Use of
ation of Smal
Angeles Mac
e and Coarse
e for Structur
s of Soil Usin
Of Rigid Cellu
ckness of Tex
low Rate per
a Constant He
s of Soils Usi
by Use of Sod
Chloride Ion i
boratory Soil R
Use in Corro
e Chloride Ion
Soluble Sulfa
ractor and
equired and th
drawings
quest.
f Sodium
ll-Size
chine
Aggregates
al Concrete
g Standard
ular Plastics
xtile
Unit Width
ead
ing a 2.5-kg
dium Sulfate
in Concrete
Resistivity
osion Testing
n Content in
ate Ion
he
Modular S
PART
T
se
co
H
ea
w
02.01.00
02
02
02.02.00
02
02
02
02.03.00
The disch
designed
discharge
ubsurface Flow
2 – COMP
he Modular S
elf-contained
ompressive s
H20 loading as
asy maintena
water transfer
0 Pretreatm
2.01.01
2.01.02
0 Biofiltratio
2.02.01
2.02.02
2.02.03
0 Discharge
harge device s
treatment flow
e chamber sha
w Wetland Sys
PONENT
Subsurface Fl
within a conc
trength of 5,0
s indicated by
ance and size
system comp
ment Cham
Filter Cartri
minute per
Drain Down
the underdr
on Chambe
Media shal
select mate
of ASTM C
minimum 2
organic ma
of the cham
retention tim
not accepta
influent end
gallons per
structure th
extending w
Planting sh
and/or land
Plant Supp
inert and co
has an inte
e Chamber
shall house a
w rate. All pip
all also conta
stem Page
S
ow Wetland S
crete structure
000 psi, with r
y AASHTO. E
d to allow rem
ponents shall
Filter netting
and strength
Drainage ce
plastic and h
and a void a
media of 75
and allow w
mber Compo
dges shall op
square foot s
n System sha
rain pipe that
er Compone
l consist of ce
erial in a rotar
330, ASTM C
4-hour water
aterial. Flow th
mber toward th
me in the med
able alternativ
d to effluent e
r minute per s
hat spaces the
walls of the co
all be native,
dscape archite
ort Media sha
ontains no ch
rnal void perc
flow control o
ping compone
in a drain dow
3 of 6
Systems (MS
e constructed
reinforcing pe
Each Chambe
moval of all in
conform with
g shall be 100
h tested per A
ells shall be m
have a minim
area along the
% or greater.
water to freely
onents
perate at a loa
surface area.
all include a pe
is connected
ents
eramic materi
ry kiln. Media
C331, and AA
absorption of
hrough media
he centralized
dia shall be a
ves. The thick
end. The loadi
square foot su
e surface of th
oncrete struct
drought toler
ect.
all be made o
emicals or fe
centage of 80
orifice plate th
ents shall be m
wn filter if spe
FWS) and all
d of concrete w
er ASTM A 61
er shall have
nternal compo
h the following
0% Polyester
ASTM D 3787
manufactured
mum compress
e surface mak
. The cells sh
flow in all fou
ading rate not
ervious floor
d to the discha
ial produced b
must be prod
ASHTO M195
f 10.5% mass
a shall be hori
d and vertical
at least 3 minu
kness of the m
ing rate on th
urface area. M
he media at le
ture.
rant species r
of a 3” thick m
rtilizers, is no
0%.
hat restricts fl
made of a hig
ecified on the
l of its compo
with a minimu
5, Grade 60,
appropriate a
onents withou
g;
with a numbe
7.
of lightweigh
sive strength
king contact w
all be at least
ur directions.
t to exceed 3
that allows w
arge chambe
by expanding
duced to mee
. Aggregates
s. Media shal
izontal from th
lly extending
utes. Downwa
media shall be
he media shal
Media must b
east 2” from a
recommend b
moisture retent
ot made of org
lows greater t
gh-density po
drawing.
onents shall be
um 28 day
and supports
access hatche
ut disassembly
er 16 sieve si
t injection-mo
test of 6,000
with the filter
t 2” in thickne
gallons per
water to drain i
r.
g and vitrifying
et the requirem
s must have a
l not contain
he outer perim
underdrain. T
ard flow filters
e at least 19”
l not exceed
be contained w
all vertically
by manufactur
tion cell that i
ganic materia
than
lyethylene. Th
e
s and
es for
y. All
ze,
olded
psi
ess
into
g
ments
a
any
meter
The
s are
from
1.1
within
rer
is
al and
he
Modular S
PART
03.01.00
03
03
03
Minimum
• System
rate shall
PART 4
04.01.00
The instal
and local
04.02.00
The Contr
(MSFWS)
ubsurface Flow
3 – PERF
0 General
3.01.01
3.01.02
3.01.03
Treatment Ca
must be capa
be controlled
4 - EXEC
0 General
llation of the M
specifications
0 Installatio
ractor shall fu
) device(s) an
w Wetland Sys
FORMANC
Function - T
on gravity f
pretreatme
pretreatme
housed in a
subsurface
through the
filter media
individual m
pipe of no g
downward
shall be thr
pollutants h
pretreatme
to the biofilt
chamber it
chamber eq
the system
Pollutants -
dissolved a
species, ba
hydrocarbo
weather flo
Treatment
will treat 10
filtration ca
those provi
residence t
apabilities
able of treatin
d by an orifice
UTION
MSFWS shal
s.
on
urnish all labo
nd appurtenan
stem Page
CE
The MSFWS
flow, unless o
nt chamber, a
nt device hou
a perforated e
piping and o
e filter cartridg
. The flow thr
media filter. In
greater than 1
into the water
readed on the
have been rem
nt chamber a
tration chamb
is collected b
quipped with
.
- The MSFWS
and particulate
acteria, BOD,
ons entering th
ws.
Flow Rate an
00% of the req
pacities listed
ded on the dr
time.
g flows to the
plate.
l conform to a
or, equipment,
nces in accord
4 of 6
has no movin
otherwise spec
a biofiltration
uses cartridge
enclosure. Th
r surface inle
ge enclosures
rough the med
n the center of
1.5” in diamet
r transfer cav
e bottom to co
moved by the
and flows into
ber. Once run
by the vertical
a flow contro
S will remove
e metals and
oxygen dema
he filter during
nd Bypass - T
quired water q
d in section 03
rawing to ens
e specified tre
all applicable
, materials an
dance with th
ng internal co
cified. The M
chamber and
e media filters
he untreated
et. Water ente
s by gravity flo
dia is horizon
f the media s
ter. The slotte
vity of the cart
onnect to the
e filter media t
the water tra
noff has been
underdrain a
l orifice plate.
and retain de
nutrients incl
anding substa
g frequent sto
The MSFWS o
quality treatm
3.02.00. The
sure proper pe
eatment flow r
national, stat
nd incidentals
he drawings a
omponents an
MSFWS is com
d a discharge
s, which cons
runoff flows in
ering the syst
ow. Then the
ntal toward the
hall be a roun
ed PVC pipe s
tridge. The slo
water transfe
the water disc
ansfer system
n filtered by th
and conveyed
. Finally the tr
ebris, sedime
luding nitroge
ances, organ
orm events an
operates in-lin
ment flow base
e size of the sy
erformance a
rate on the dr
te, state highw
s required to in
and these spe
nd functions b
mposed of a
chamber. Th
ist of filter me
nto the system
tem is forced
e flow contact
e center of ea
nd slotted PV
shall extend
otted PVC pip
er cavity. Afte
charges the
and is conve
he biofiltration
d to a discharg
reated flow ex
ents, TSS,
en and phosp
ic compounds
nd continuous
ne. The MSFW
ed on a minim
ystem must m
nd hydraulic
rawings. The
way, municipa
nstall the
ecifications.
based
he
edia
m via
ts the
ach
VC
pe
er
eyed
n
ge
xits
horus
s and
s dry
WS
mum
match
flow
al
Modular S
04
04
04
04
04
04
04.03.00
04
04
04.04.00
04
ubsurface Flow
4.02.01
4.02.02
4.02.03
4.02.04
4.02.05
4.02.06
0 Shipping
4.03.01
4.03.02
0 Maintena
4.04.01
w Wetland Sys
Grading an
professiona
After site is
companies
shall be ap
excavation.
agencies re
stored, and
the contrac
grading and
Compaction
engineer’s
Backfill sha
recommend
structures.
Concrete S
and approv
per plans.
Subsurface
damage the
shall be fille
Planting lay
minimum 3
survival rate
recommend
drip irrigate
chemical he
and mainte
, Storage a
Shipping –
is the respo
site of insta
Storage an
handling of
repair or re
accepted a
MSFWS(s)
inside the o
The MSFW
and NIOSA
professiona
ance and In
Inspection –
has been p
appropriate
installation
installation.
been instal
stem Page
d Excavation
al surveyor, a
s marked it is
and/or DigAl
proved by go
. Soil conditio
equirements.
d handled per
ctor to install a
d excavation
n – All soil sh
recommenda
all be placed a
dations, and w
Structures – A
ved the concre
e Flow Wetlan
e Wetland Lin
ed to a level 9
yer shall be in
” grow enhan
e, and 6” of w
ded by manuf
ed for at least
erbicides, pes
enance of the
and Handlin
MSFWS sha
onsibility of th
allation.
d Handling– T
f the MSFWS
placement co
nd unloading
and all comp
original shippi
WS shall alway
A lifting recom
al recommend
nspection
– After install
properly instal
e components
shall be subje
. In addition,
led per the m
5 of 6
site shall be
nd clearly ma
the responsib
ert to check f
verning agen
ons shall be t
All earth rem
governing ag
and maintain
operations.
all be compa
ations prior to
according to a
with a minimu
After backfill h
ete structures
nd Media sha
ner or Water T
9 inches below
nstalled per m
ncement medi
wetland media
facturer and/o
the first 3 mo
sticides, or fe
planted area
ng
ll be shipped
e contractor t
The contracto
and all comp
osts associate
has commen
ponents shall
ng container
ys be handled
mmendations a
dations.
ation, the con
led at the cor
s. All compon
ect to inspect
the contracto
manufacturer’s
properly surv
arked with exc
bility of the co
for undergrou
ncies before c
tested in acco
moved shall be
gencies stand
proper erosio
acted per regis
installation o
a registered p
um of 6” of gra
as been inspe
s shall be lifte
ll be carefully
Transfer Syst
w finished su
manufacturer’s
ia that ensure
a. Planting sh
or landscape
onths to insur
ertilizers shall
.
to the contra
to offload the
or shall exerc
ponents prior
ed with events
nced shall be
always be sto
until the unit(
d with care an
and/or contra
ntractor shall
rrect location(
nents associa
tion by the en
or shall demo
s specification
veyed by a re
cavation limit
ontractor to co
und utilities. A
commenceme
ordance with t
e transported
dards. It is th
on control me
stered profes
of MSFWS co
professional s
avel under al
ected by the
ed and placed
y loaded into a
tems. The en
rface.
s drawings an
es greater tha
hall consist of
architect. Pla
re long term p
be used in th
actor’s addres
unit(s) and p
cise care in th
to and during
s occurring af
born by the c
ored indoors
(s) are ready
nd lifted accor
actor’s workpla
demonstrate
(s), elevations
ated with the M
ngineer at the
nstrate that th
ns and recom
egistered
s and elevatio
ontact local ut
All grading pe
ent of grading
the governing
d, disposed,
e responsibili
asures during
ssional soils
mponents.
soils engineer
l concrete
governing ag
d in proper po
area so not to
ntire wetland a
nd consist of a
an 95% plant
f native plants
anting shall b
plant growth.
he planting or
ss or job site,
place in the ex
e storage and
g installation.
fter delivery is
contractor. T
and transpor
to be installe
rding to OSHA
ace safety
that the MSF
s, and with
MSFWS and
place of
he MSFWS h
mendations.
ons.
tility
ermits
and
g
ity of
g
r’s
ency
osition
o
area
a
s
be
No
care
and
xact
d
Any
s
he
rted
d.
A
FWS
its
as
All
Modular S
04
04
PART
05.01.00
The Manu
workmans
notified of
recomme
05.02.00
The MSFW
Certificate
solids, ph
ubsurface Flow
4.04.02
4.04.03
5 – QUAL
0 Warranty
ufacturer shal
ship for a per
f repair or rep
nded applicat
0 Performa
WS manufact
e” certifying th
osphorous an
w Wetland Sys
component
inspection s
Maintenanc
maintenanc
The mainte
Manual is a
detailed info
Maintenanc
record shal
description
Material Dis
MSFWS sh
in accordan
regulations
LITY ASS
y
l guarantee th
iod of (5) yea
placement iss
tion for which
ance Certifi
turer shall sub
he MSFWS is
nd dissolved m
stem Page
ts shall be ins
shall be kept
ce – The man
ce of once a y
enance shall b
available upon
ormation rega
ce/Inspection
l include any
of debris coll
sposal - All de
hall be transpo
nce with local
for the prope
SURNACE
he MSFWS a
ars from the da
ues in writing
it was design
cation
bmit to the En
s capable of a
metals.
6 of 6
spected by a q
in an inspect
nufacturer rec
year and repla
be performed
n request from
arding the ma
record shall
maintenance
lected, and th
ebris, trash, o
orted and dis
and state req
er disposal of
E
against all ma
ate of delivery
within the wa
ned.
ngineer of Re
achieving the
qualified pers
ion log.
commends cle
acement of th
by someone
m the manufa
aintenance of
be kept by th
e activities pre
he condition o
organics, and
posed of at a
quirements.
toxic and non
nufacturing d
y to the ____
arranty period
ecord a “Manu
specified rem
son once a ye
eaning and de
he Cartridge F
qualified. A
acturer. The m
f the MSFWS
e maintenanc
eformed, amo
of the filter.
sediments ca
an approved fa
Please refer t
n-toxic mater
defects in mat
___. The man
d. The MSFW
ufacturer’s Pe
moval efficienc
ear and result
ebris removal
Filters as nee
Maintenance
manual has
. A
ce operator.
ount and
aptured by th
acility for disp
to state and lo
rial.
terials and
nufacturer sha
WS is limited t
erformance
cy for suspen
s of
l
eded.
e
The
e
posal
ocal
all be
to
nded
Page 1 of 14
RECORDING REQUESTED BY AND
WHEN RECORDED RETURN TO:
CITY OF CHULA VISTA
OFFICE OF THE CITY CLERK
276 FOURTH AVENUE
CHULA VISTA, CA 91910
This Instrument Benefits City Only. Above Space for Recorder’s Use
No Fee Required.
CCV File No.: DR18-0019
STORM WATER MANAGEMENT FACILITIES MAINTENANCE
AGREEMENT WITH GRANT OF ACCESS AND COVENANTS
310-316 K Street
THIS STORM WATER MANAGEMENT FACILITIES MAINTENANCE AGREEMENT
(“Agreement”), dated ________ ______, 20__ for the purpose of reference only and effective the
date on which the last party hereto affixes his/her signature ("Effective Date"), is entered into
between Dan Floit (“Owner(s)”) and the City of Chula Vista, a municipal corporation, (“City”)
(individually, each may be referred to as “Party” and collectively as “Parties”) with ref erence to
the following facts:
RECITALS
WHEREAS, Owner(s) has(have) applied for Grading Permit for the development of
310-316 K Street , (“Project”), located on parcels 573-450-04-00, and 576-450-05-00
“Project Site” as depicted in Exhibit “A” and more particularly described in Exhibit “B”,
both attached hereto and incorporated herein by reference ; and
WHEREAS, as a condition of the Grading Permit Issuance, Owner(s) is(are) required to
implement and maintain structural or non-structural pollution prevention measures, such as site
design, source control, treatment control, and hydromodification control (where applicable)
methods required to minimize polluted runoff and any other environmental impacts from Project
during the post-development phase (collectively “BMPs”); and
WHEREAS, pursuant to City’s urban runoff regulations , including Chula Vista
Municipal Code, Chapter 14.20 (the “Storm Water Management and Discharge Control
Ordinance) and the Chula Vista BMP Design Manual, Owner(s) is(are) required to prepare and
submit a Stormwater Quality Management Plan (SWQMP), which includes an Inspection,
Operation, and Maintenance Plan (IOMP); and
2
WHEREAS, the Owner(s) has(have) submitted SWQMP, which is on file in the office of
the City Engineer; and
WHEREAS, the SWQMP proposes that storm water runoff from Project be detained and
treated by the use of permanent Storm Water Management Facilities (“SWMFs”); and
WHEREAS, the SWMFs are classified in the SWQMP as site design, treatment control,
and hydromodification control BMPs; and
WHEREAS, the SWQMP specifies the manner and standards by which the SWMFs must
be inspected, maintained, and repaired in order to retain their effectiveness; and
WHEREAS, prior to the issuance of any construction permits for Project, City requires
Owner(s) to enter into Agreement to ensure the installation, inspection, maintenance, and repair
of permanent SWMFs.
NOW, THEREFORE, for good and valuable consideration, the receipt and sufficiency of
which are hereby acknowledged, the parties agree to the following covenants, terms, and
conditions:
ARTICLE I. DEFINITIONS
1.1 Unless context indicates otherwise, for the purpose of this Agreement, all the below -listed
terms shall be defined as follows:
“Agreement” means this Storm Water Management Facilities Maintenance Agreement.
“Best Management Practices, or BMPs” means structural or non -structural pollution
prevention measures, such as site design, source control, treatment control, and
hydromodification control methods required to minimize polluted runoff from Project
during the post-development phase. BMPs include, but are not limited to, Storm Water
Management Facilities.
“City” means the City of Chula Vista, an official of the City, or any staff member
authorized to act on behalf of the City.
“Inspection, Operation, and Maintenance Plan, or IOMP” means a description of
inspection, operation, and maintenance activities and schedules required to ensure proper
operation and effectiveness of the SWMFs into perpetuity.
“Owner(s)” means the land owner(s) of Project Site, which is the subject of this
Agreement, anyone authorized to act on behalf of the land owner(s) of Project Site, and any
and all of owner’s successors in interest, whether individual, partnership, corporation, or
other entity such as a Home Owners’ Association, regardless of the manner of transfer,
including purchase, devise, or gift. If land owner of SWMFs is different from development
3
land owner (as may be in the case of offsite SWMFs), both owners are parties to
Agreement and shall sign the Signature Page as Owner(s)
“Project” means all improvements and land dedicated to the development, which is the
subject of Agreement, including any offsite water quality facilities.
“Project Site” means the land dedicated to the development, which is the subject of
Agreement, including any offsite water quality facilities.
“Responsible Party” means Owner(s) and any other person, corporation, or legal entity
accepting, in writing and in City approved form, responsibility on behalf of Owner(s).
“Security” means any Bond, Cash Deposit, or Letter of Credit that City may require from
Owner(s) to assure the faithful performance of the obligations of Agreement.
“Storm Water Management Facilities” (“SWMFs”) means all onsite and off site structural
facilities constructed as Project’s site design, treatment control, or hydromodification
control BMPs, proposed as part of the development project submittals, and as approved by
City prior to the issuance of a development permit, or as amen ded with City’s approval
after the development is complete.
“Water Quality Technical Report” (“SWQMP”) means a document prepared in accordance
with the requirements of the Chula Vista Development Storm Water Manual, and submitted
to the City as part of Project’s permit application documents.
ARTICLE II. – OWNER’S OBLIGATIONS
2.1 Maintenance of Stormwater Management Facilities. Owner(s) shall install, inspect,
maintain, repair, and replace all SWMFs for the Project as required by the Director of
Public Works, or his/her designated representative (“Director).
2.1.1 Scope of Maintenance. Maintenance shall include inspection and servicing of
SWMFs on the schedule determined necessary to ensure the SWMFs retain their
effectiveness.
2.1.2 Duration of Obligation. Owner’s obligation to maintain, repair and replace the
SWMFs shall continue in perpetuity until all obligations under this Agreement are
transferred to, and assumed by, another owner or entity approved by City
(“Responsible Party”).
2.2 Grant of Right of Entry. Owner(s) shall grant to the City, its representatives, or
contractors, or any Responsible Party, the right to enter the Project to inspect SWMFs, or
perform any permitted acts or obligations under this Agreement, including maintenance of
said facilities in the event the Owner(s) fails(fail) to fulfill its(their) maintenance
obligations after proper notice.
4
2.2.1 No Prior Notice. City shall have the right, at any time and without prior notice to
Owner(s), to enter upon any part of Project as may be necessary or convenient for any
acts permitted hereunder.
2.2.2 Unobstructed Access. Owner(s) shall at all times maintain Project so as to make
City’s access clear and unobstructed.
2.3 Modification of IOMP. Owner(s) shall, at the City’s request, in City’s sole discretion,
amend the IOMP. The Owner(s) may amend the IOMP from time-to-time, subject to City
approval. The IOMP is attached hereto as Exhibit “C.”
2.3.1 Part of Owner’s Obligations. Any obligations, conditions, or requirements of an
amended IOMP shall become part of this Agreement immediately as if originally
included herein, and the Owner(s) shall be responsible for such amended obligations,
conditions, or requirements. The amended IOMP shall not be applied retroactively.
The IOMP shall describe employee training programs and duties, routine inspection,
service and operating schedules, maintenance frequency, and specific maintenance
activities.
2.4 Submission of Documents. Owner(s) shall include a copy of the Inspection, Operation,
and Maintenance Plan (“IOMP”) for the SWMFs in the SWQMP for Project and submit a
copy to City, at the time Agreement is executed.
ARTICLE III. – CITY’S RIGHTS
3.1 Perform Maintenance. City shall have the right, but not the obligation, to elect to
perform any or all of the maintenance activities
3.1.1 Notice. Except in the Case of an emergency, prior to performing any maintenance
activities, City shall provide Owner(s) with a written notice, informing Owner(s) of
its (their) failure to satisfactorily perform its (their) obligations under Agreement.
3.1.1.1 Emergencies. In the event of an emergency, as determined by City, City shall
not be required to provide Owner(s) with notice in advance of performing any
and all maintenance activities it deems necessary.
3.1.2 Time to Cure. Owner(s) shall have a reasonable time, as defined in the Notice, to
cure any failure to perform its (their) maintenance obligations. If a cure cannot be
completed within the time limit identified in the Notice, Owner(s) shall provide City
with a written request for additional time, which shall include sufficiently detailed
explanation as to why the cure cannot be completed within such timeframe. If the
City approves a request for additional time, Owner(s) shall immediately commence
such cure and diligently pursue to completion.
5
3.1.3 Costs of Maintenance. In the event City performs any maintenance under this Article
III, then Owner(s) shall pay all costs City incurred in performing said maintenance
activities. Payment shall be subject to the following terms:
3.1.3.1 Due Date. Net 30.
3.1.3.2 Interest. Any late payment shall be subject to a rate of eight percent (8%)
interest per annum.
3.1.3.3 Use of Security. If payment is not received by the Due Date, City may, at its
option, recover its costs through use of any security provided by Owner (s).
Any costs associated with recovery shall be charged to and be an obligation of
Owner(s).
3.2 City Inspections. City shall have the right to conduct inspections of the SWMFs from
time-to-time as required by the National Pollutant Discharge Elimination System
Municipal Permit, Order No. R9-2013-0001 and any re-issuances thereof, to ensure
adequate maintenance and effectiveness of the SWMFs. Owner(s) agrees (agree) to pay all
inspection fees as may be established by City.
ARTICLE IV. INDEMNITY
4.1 General Requirement. Owner(s) shall defend, indemnify, protect and hold harmless the
City, its elected and appointed officers, agents, employees, and volunteers (“Indemnitees”)
from and against any and all claims, demands, causes of action, costs, expenses, liability,
loss, damage or injury, in law or equity, to property or persons, including wrongful death,
in any manner arising out of or incident to any alleged acts, omissions, negligence, or
willful misconduct of Owner(s), its officials, officers, employees, agents, and contractors
(“Indemnitors”), arising out of or related to the installation, inspection, maintenance, repair,
or replacement of the BMPs or this Agreement. This indemnity pr ovision does not include
any claims, damages, liability, costs and expenses (including without limitations, attorneys
fees) arising from the sole negligence or sole willful misconduct of the Indemnitees. Also
covered is under the indemnity obligations is liability arising from, connected with, caused
by or claimed to be caused by the active or passive negligent acts or omissions of the
Indemnitees, which may be in combination with the active or passive negligent acts or
omissions of the Indemnitors.
4.2 Costs of Defense and Award. Included in the obligations in Section 4.1, above, is the
Owner’s obligation to defend, at Owner’s own cost, expense and risk, any and all aforesaid
suits, actions or other legal proceedings of every kind that may be brought or i nstituted
against the Indemnitees. Owner(s) shall pay and satisfy any judgment, award or decree that
may be rendered against Indemnitees for any and all legal expense and cost incurred by
each of them in connection therewith.
4.3 Conduct Own Defense. If City elects, at its sole discretion, to conduct its own defense,
participate in its own defense, or obtain independent legal counsel in defense on any claim
6
related to the installation, inspection, maintenance, repair or replacement of the SWMFs,
Owner(s) agrees (agree) to pay the reasonable value of attorney’s fees and all of City’s
reasonable costs.
4.4 Insurance Proceeds. Owner’s obligation to indemnify shall not be restricted to insurance
proceeds, if any, received by Indemnitees.
4.5 Declarations. Owner’s obligations under this Article IV shall not be limited by any prior
or subsequent declaration by the Owner(s).
4.6 Enforcement Costs. Owner(s) agrees (agree) to pay any and all costs Indemnitees incur
enforcing the indemnity and defense provisions set forth in this Article IV.
4.7 Survival. Owner’s obligations under this Article IV shall survive the termination of this
Agreement.
ARTICLE V. INSURANCE
5.1 Insurance. In the event that insurance is required by City, Owner(s) shall not begin work
under this Agreement until it has (they have) : (i) obtained, and upon the City’s request
provided to the City, insurance certificates reflecting evidence of all insurance required in
this Article V; (ii) obtained City approval of each company or compani es; and (iii)
confirmed that all policies contain the specific provisions required by this Section.
5.2 Types of Insurance. At all times during the term of this Agreement, Owner(s) shall
maintain those types of insurance coverage and amounts of coverag e required by City to
protect the City from any potential claims, which may arise from the installation,
inspection, maintenance, repair or replacement of the SWMFs or any other obligations
under this Agreement.
5.3 Policy Endorsements Required.
5.3.1 Additional Insureds. City of Chula Vista, its officers, officials, employees, agents
and volunteers are to be named as additional insureds with respect all required
policies of insurance with respect to liability arising out of obligations under this
Agreement performed by or on behalf of the Owner(s).
5.3.2 Primary Insurance. The Owner’s General Liability insurance coverage must be
primary insurance as it pertains to the City, its officers, officials, employees, agents,
and volunteers. Any insurance or self-insurance maintained by the City, its officers,
officials, employees, or volunteers is wholly separate from the insurance of the
Owner(s) and in no way relieves the Owner(s) from its (their) responsibility to
provide insurance.
7
5.3.3 Waiver of Subrogation. Owner’s insurer will provide a Waiver of Subrogation in
favor of the City for each required policy providing coverage for the term required by
this Agreement.
5.3.4 Cancellation. The insurance policies required must be endorsed to state that c overage
will not be canceled by either party, except after thirty (30) days’ prior written notice
to the City by certified mail, return receipt requested. The words “will endeavor” and
“but failure to mail such notice shall impose no obligation or liabili ty of any kind
upon the company, its agents, or representatives” shall be deleted from all certificates.
5.4 Proof of Insurance Coverage. Owner(s) shall furnish the City with original certificates
and amendatory endorsements affecting coverage required. The endorsements should be
on insurance industry forms, provided those endorsements or policies conform to the
contract requirements. All certificates and endorsements are to be received and approved
by the City before work commences on the Project. The City reserves the right to require,
at any time, complete, certified copies of all required insurance policies, including
endorsements evidencing the coverage required by these specifications.
5.5 Deductibles and Self -Insured Retentions. Any deductibles or self-insured retentions
must be declared to and approved by the City. At the option of the City, either the insurer
will reduce or eliminate such deductibles or self-insured retentions as they pertain to the
City, its officers, officials, employees and volunteers; or the Owner(s) will provide a
financial guarantee satisfactory to the City guaranteeing payment of losses and related
investigations, claim administration, and defense expenses.
5.6 Active Negligence. Coverage shall not extend to any inde mnity coverage for the active
negligence of the additional insureds in any case where an agreement to indemnify the
additional insured would be invalid under Subdivision (b) of Section 2782 of the Civil
Code.
5.7 Not a Limitation of Other Obligations. Insurance provisions under this Article shall not
be construed to limit the Owner’s obligations under this Agreement, including Indemnity.
ARTICLE VI. SECURITY
6.1 Security Required. If within any five-year period, City inspectors determine on two
occasions that Owner(s) has (have) failed to effectively operate, maintain, or repair the
SWMFs, City may require Owner(s) to provide City with Security to assure the faithful
performance of the obligations of this Agreement.
6.1.1 Amount of Security. The amount of the security shall equal the cost to maintain the
SWMFs for two (2) years, which cost shall be determined as identified in the Project
SWQMP (“Security Amount”).
6.1.2 Type of Security. Security may be of any of the following types:
8
6.1.2.1 Performance Bond. Owner(s) shall provide to the City a performance bond in
favor of the City in the Security Amount and subject to the provisions below.
a. Certificate of Agency. All bonds signed by an agent must be accompanied
by a certified copy of such agent’s authority to act.
b. Licensing and Rating. The bonds shall be from surety companies admitted
to do business in the State of California, licensed or authorized in the
jurisdiction in which the Project is located to issue bonds for the limits
required by this agreement, listed as approved by the United States
Department of Treasury Circular 570, http://www.fms.treas.gov/c570, and
which also satisfy the requirements stated in Section 995.660 of the Code
of Civil Procedure, except as provided otherwise by laws or regulation,
and have a minimum AM Best rating of “A-” to an amount not to exceed
ten percent (10%) of its capital and surplus.
c. Insolvency or Bankruptcy. If the surety on any bond furnished by the
Owner(s) is declared bankrupt or becomes insolvent or its right to do
business is terminated in any state where any part of the Project is located,
Owner(s) shall within seven (7) days thereafter substitute or require the
substitution of another bond and surety, acceptable to the City.
6.1.2.2 Letter of Credit. As security for Owner’s obligations under this Agreement,
Owner(s) shall cause an irrevocable letter of credit in the Security Amount
(“Letter of Credit”) to be issued in favor of the City by a reputable state or
national financial institution with a branch located in Chula Vista.
a. Draw on Letter of Credit. The City may draw upon the Letter of Credit
for the full amount or any series of partial amounts as necessary by means
of a sight draft accompanied by a statement from the City Manager,
Deputy City Manager, Business Center Manager, that the Owner(s)
has(have) not satisfied Owner’s obligations hereunder.
6.1.2.3 Cash Deposit. In lieu of a Performance Bond or Letter of Credit, Owner (s)
may deposit the Security Amount with the City.
a. Return of Security. Any unused balance of the Security at the end of the
Term shall be returned to the Owner(s) in accordance with City’s
accounting procedures.
6.1.3 Adjustment for Inflation. The Security Amount shall be adjusted at a rate of 5% per
annum.
6.1.4 Term. Security shall remain in full force and effect for two (2) years from the date it
is received by the City provided no further failures are identified by City Inspectors
during the initial two (2) year period. In the event additional violation s occur, the
9
City shall retain the Security until such time as the City Manager, in his sole
discretion, deems appropriate to ensure the Owner’s obligations will be satisfied.
6.1.5 Form of Security. Security required under this Article shall be in a form satisfactory
to the City Manager and City Attorney.
6.1.6 Use of Security. In accordance with Article III, City may use all or any portion of
this Security to fund the costs associated with the City’s performance of any of the
maintenance activities for the Project’s SWMFs.
6.1.7 Replenish Security. If at any time the Security Amount shall drop below the amount
required under Section 6.1.1, Owner(s) shall deposit additional funds, provide an
additional Letter of Credit to City, or provide an additiona l bond within thirty (30)
days, such that the total amount of Security available to the City is equal to the
amount required in Section 6.1.1.
ARTICLE VII. RECORDS
7.1 Record Keeping. The designation of a Responsible Party to maintain the SWMFs does
not relieve Owner(s) of any of the obligations or duties under this Agreement. Owner (s),
its (their) successors, or a designated Responsible Party, shall retain records of the IOMP
and maintenance and inspection activities for at least five years. Said rec ords shall be
made available within 5 days, upon request by City.
ARTICLE VIII. STANDARD PROVISIONS
8.1 Headings. All headings are for convenience only and shall not affect the interpretation of
this Agreement.
8.2 Gender & Number. Whenever the context requires, the use herein of (i) the neuter gender
includes the masculine and the feminine genders and (ii) the singular number includes the
plural number.
8.3 Reference to Paragraphs. Each reference in this Agreement to an Article or Section
refers, unless otherwise stated, to an Article or Section in this Agreement.
8.4. Incorporation of Recitals. All recitals herein are incorporated into this Agreement and
are made a part hereof.
8.5 Covenants and Conditions. All provisions of this Agreement expressed as either
covenants or conditions on the part of the City or the Owner (s), shall be deemed to be both
covenants and conditions.
8.6 Integration. This Agreement and the Exhibits and references incorporated into this
Agreement fully express all understandings of the Parties concerning the matters covered in
this Agreement. No change, alteration, or modification of the terms or conditions of this
10
Agreement, and no verbal understanding of the Parties, their officers, agents, or employees
shall be valid unless made in the form of a written change agreed to in writing by both
Parties or an amendment to this Agreement agreed to by both Parties. All prior negotiations
and agreements are merged into this Agreement.
8.7 Severability. The unenforceability, invalidity, or illegality of any provision of this
Agreement shall not render any other provision of this Agreement unenforceable, invalid,
or illegal. In the event that any provision of this Agreement shall for any reason, be
determined to be invalid, illegal, or unenforceable in any respect, the remainder of this
Agreement shall remain in full force and effect and the parties hereto shall negotiate in
good faith and agree to such amendments, modifications, or supplements to this Agreement
or such other appropriate action as shall, to the maximum extent practicable in light of such
determination, implement and give effect to the intentions of the parties as reflected herein.
8.8 Drafting Ambiguities. The Parties agree that they are aware that they have the right to be
advised by counsel with respect to the negotiations, terms and conditions of this
Agreement, and the decision of whether or not to seek advice of counsel with respect to this
Agreement is a decision that is the sole responsibility of each Party. This Agreement shall
not be construed in favor of or against either Party by reason of the extent to which each
Party participated in the drafting of the Agreement.
8.9 Conflicts Between Terms . If an apparent conflict or inconsistency exists between the
main body of this Agreement and the Exhibits, the main body of this Agreement shall
control. If a conflict exists between an applicable federal, state, or local law, rule,
regulation, order, or code and this Agreement, the law, rule, regulation, order, or code shall
control. Varying degrees of stringency among the main body of this Agreement, the
Exhibits, and laws, rules, regulations, orders, or codes are not deemed conflicts, and the
most stringent requirement shall control. Each Party shall notify the other immediately
upon the identification of any apparent conflict or inconsistency concerning this
Agreement.
8.10 Prompt Performance. Time is of the essence of each covenant and condition set forth in
this Agreement.
8.11 Good Faith Performance. The Parties shall cooperate with each other in good faith, and
assist each other in the performance of the provisions of this Agreement.
8.12 Further Assurances. City and Owner each agree to execute and deliver such additional
documents as may be required to effectuate the purposes of this Agreement.
8.13 Exhibits. Each of the following Exhibits is attached hereto and incorporated herein by this
reference:
Exhibit A: Vicinity map
Exhibit B: Legal Description for Project
Exhibit C: BMP and HMP type, location and dimensions
11
Exhibit D: Maintenance recommendations and frequency. Inspection, Operation, and
Maintenance Plan (IOMP)
8.14 Compliance with Controlling Law. The Owner(s) shall comply with all laws, ordinances,
regulations, and policies of the federal, state, and local governments applicable to this
Agreement. In addition, the Owner(s) shall comply immediately with all directives issued
by the City or its authorized representatives under authority of any laws, statutes,
ordinances, rules, or regulations.
8.15 Enforcement. Failure to comply with the terms of this Agreement constitutes a violation
of the Chula Vista Municipal Code Chapter 14.20 “Storm Water Management and
Discharge Control” and may result in enforcement action pursuant to City’s storm water
regulations and administrative procedures.
8.16 Jurisdiction, Venue, and Attorney Fees . This Agreement shall be governed by and
construed in accordance with the laws of the State of California. Any action arising u nder
or relating to this Agreement shall be brought only in the federal or state courts located in
San Diego County, State of California, and if applicable, the City of Chula Vista, or as
close thereto as possible. Venue for this Agreement, and performanc e hereunder, shall be
the City of Chula Vista. The prevailing Party in any such suit or proceeding shall be
entitled to a reasonable award of attorney fees in addition to any other award made in such
suit or proceeding.
8.17 Administrative Claims Requirement and Procedures. No suit shall be brought arising
out of this agreement, against the City, unless a claim has first been presented in writing
and filed with the City of Chula Vista and acted upon by the City of Chula Vista in
accordance with the procedures set forth in Chapter 1.34 of the Chula Vista Municipal
Code, the provisions of which are incorporated by this reference as if fully set forth herein.
8.18 Third Party Relationships. Nothing in this Agreement shall create a contractual
relationship between City and any individual, entity, or other not a party to this Agreement.
8.19 Non-Assignment. The Owner(s) shall not assign the obligations under this Agreement,
whether by express assignment, by sale of the company, or any monies due or to become
due, without the City's prior written approval. Any assignment in violation of this
paragraph shall constitute a Default. In no event shall any putative assignment create a
contractual relationship between the City and any putative assignee.
8.20 Successors in Interest. This Agreement and all rights and obligations created by this
Agreement shall be in force and effect whether or not any Parties to the Agreement have
been succeeded by another entity, and all rights and obligations created by this Agreem ent
shall be vested and binding on any Party's successor in interest.
8.21 Agreement Runs with Project. The terms, covenants and conditions contained in this
Agreement shall constitute covenants running with the land and shall be binding upon the
heirs, executors, administrators, successors and assigns of Owner(s) and City and shall be
12
deemed to be for the benefit of all persons owning any interest in Project, the City, and the
Public. It is the intent of the Parties that this Agreement be recorded and be binding upon
all persons purchasing or otherwise acquiring all or any lot, unit or other portion of Project,
who shall be deemed to have consented to and become bound by all the provisions of this
Agreement. This Agreement shall commence upon execution of this Agreement by all
Parties named in the Agreement.
8.22 Independent Contractors. The Owner(s), any contractors, subcontractors, and any other
individuals employed by the Owner(s) shall be independent contractors and not agents of
the City. Any provisions of this Agreement that may appear to give the City any right to
direct the Owner(s) concerning the details of performing the Services under this
Agreement, or to exercise any control over such performance, shall mean only that the
Owner(s) shall follow the direction of the City concerning the end results of the
performance.
8.23 No Waiver. No failure of either the City or Owner(s) to insist upon the strict performance
by the other of any covenant, term or condition of this Agreement, nor any failure to
exercise any right or remedy consequent upon a breach of any covenant, term, or condition
of this Agreement, shall constitute a waiver of any such breach of such covenant, term or
condition. No waiver of any breach shall affect or alter this Agreement, and each and every
covenant, condition, and term hereof shall continue in full force and effect to any existing
or subsequent breach.
8.24 Notices. Owner(s) agrees(agree) that it shall, prior to transferring ownership of any land
on which any part of the Project covered by this Agreement are located, and also prior to
transferring ownership of any such SWMFs, provide clear written notice of the above
maintenance obligations associated with that SWMF to the transferee. Owner(s) further
agrees(agree) to provide evidence that Owner(s) has(have) requested the California
Department of Real Estate to include in the public report issued for the development of
Project, a notification regarding the SWMF maintenance requirements described in this
Agreement.
8.24.1 Serving Notice. All notices, demands or requests provided for or permitted to be
given pursuant to this Agreement must be in writing. All notices, demands and
requests to be sent to any Party shall be deemed to have been properly given or
served if personally served or deposited in the United States mail, addressed to such
party, postage prepaid, registered or certified, with return receipt requested
8.25 Entitlement to Subsequent Notices. No notice to or demand on the Parties for notice of
an event not herein legally required to be given shall in itself create the right in the Parties
to any other or further notice or demand in the same, similar or other circumstances.
8.26 Remedies. The rights of the Parties under this Agreement are cumulative and not
exclusive of any rights or remedies that the Parties might otherwise have unless this
Agreement provides to the contrary.
13
8.27 Counterparts. This Agreement may be executed in more than one counterpart, each of
which shall be deemed to be an original but all of which, when taken together shall
constitute but one instrument.
8.28 Signing Authority. Each signatory and party hereto hereby warrants and represents to the
other party that it has legal authority and capacity and direction from its principal to enter
into this Agreement; that all resolutions or other actions have been taken so as to enable it
to enter into this Agreement and agrees to hold the other Party or Parties hereto harmless if
it is later determined that such authority does not exist.
End of page (next page is signature page)
14
SIGNATURE PAGE FOR
STORM WATER MANAGEMENT FACILITIES MAINTENANCE
AGREEMENT WITH GRANT OF ACCESS AND COVENANTS
(310-316 K Street)
IN WITNESS WHEREOF, the parties have executed this Agreement on the day of
, 20__.
OWNER: CITY OF CHULA VISTA:
City Engineer
Dan Floit
Signature: APPROVED AS TO FORM:
Its:
City Attorney
By:
Its:
ATTEST:
City Clerk
Dated:
(Notary to attach acknowledgment for each signature.)
(Corporate Authority required for each Signatory, if applicable.)
Attachments:
1. Exhibit A: Depiction of Project Site
2. Exhibit B: Legal Description for Project Site
3. Exhibit C: BMP and HMP type, location and dimensions
4. Exhibit D: Maintenance recommendations and frequency. Inspection, Operation, and
Maintenance Plan (IOMP)
J:\Engineer\LANDDEV\Projects\Planning Projects\DRC\2018\DR18-0019 310-316 K St\DR18-0019 310-316 K st. Storm Water Maintenance
Agreement.doc
VICINITY MAP
EXHIBIT A
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
ETTLER EWECKKL
ENGINEERING
DATE: 4-23-2019
LEGAL DESCRIPTION
EXHIBIT B
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
ETTLER EWECKKL
ENGINEERING
DATE: 4-23-2019
LEGEND
DRAINAGE MANAGEMENT
AREA BOUNDARY
DRAINAGE MANAGEMENT
SUB AREA
DMA2
DMA1
DMA1
BMP1BMP TREATMENT LOCATION
MWU1MODULAR WETLAND UNIT
K STREET
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
ETTLER EWECKKL
ENGINEERING
DATE: 4-23-2019
EXHIBIT C
DMA4
DMA3
310-316 K STREET
SHEET 1 OF 2
BMP1
(MWU1)
BMP2
(MWU2)
STORM DRAIN
STORM DRAIN WET WELL
AND PUMP
CURB OUTLET
BUILDING LIMITS
BMP 3 (SELF-MITIGATING)
BMP 4 (LANDSCAPE)
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
ETTLER EWECKKL
ENGINEERING
DATE: 4-23-2019
EXHIBIT C
310-316 K STREET
SHEET 2 OF 2
EXHIBIT D
OPERATIONS & MAINTENANCE SCHEDULE
310 – 316 K STREET
APARTMENT HOUSING POST
CONSTRUCTION BMP
MAINTENANCE, RESPONSIBILITY, AND
FREQUENCY MATRIX
RESPONSIBLE PARTY: LAND OWNER
BEST
MANAGEMENT
PRACTICES
(BMPS)
INSPECTION
FREQUENCY
MAINTENANCE & REPAIR ACTIVITIES
BMP #1 & 2
MODULAL
WETLAND UNIT
WITHIN 6 TO 12
MONTHS
WITHING 12 TO 24
MONTHS
-REMOVE TRASH FROM SCREENING DEVICE
- TRIM VEGATATION
-REMOVE SEDIMENT FORM SEPARATION
CHAMBER
- REPLACE CARTRIDGE FILTER MEDIA
- REPLACE DRAIN DOWN FILTER MEDIA
BMP #3 NON-
STORM WATER
DISCHARGE
CONTINUOUS
AND
ANNUALLY
-TRAINING OF LANDOWNER
-MAINTAIN LEGIBILITY OF STORM DRAIN INLET
SIGNAGE/STENCILING
-ISOLATE PROBLEM AREAS AND PLUG ILLEGAL
DISCHARGE POINTS
-ON PAVED AREAS, CLEAN UP SPILLS WITH AS
LITTLE WATER AS POSSIBLE
-FOR SMALL SPILLS, USE ABSORBENT MATERIALS
RATHER
THEN HOSING DOWN SPILL AREA
BMP #4
EFFICIENT
IRRIGATION
MONTHLY -TRAINING OF LANDOWNER
-INSPECT EQUIPMENT WATER SENSORS,
IRRIGATION HEADS, AND TIMING MONTHLY
TO ENSURE PROPER FUNCTION
-INSPECT IRRIGATION SYSTEM PERIODICALLY
TO ENSURE THAT THE RIGHT AMOUNT OF
WATER IS BEING APPLIED AND THAT EXCESSIVE
RUNOFF IS NOT OCCURRING. MINIMIZE EXCESS
WATERING AND REPAIR LEAKS IN THE
IRRIGATION SYSTEM AS SOON AS THEY ARE
OBSERVED
-SWEEP PAVED AREAS REGULARLY TO COLLECT
LOOSE PARTICLES
-WIPE UP SPILLS WITH RAGS OR OTHER
ABSORBENT MATERIAL IMMEDIATELY, DO NOT
HOSE DOWN THE AREA TO A STORM DRAIN
-SWITCH TO NON-TOXIC CHEMICALS FOR
MAINTENANCE WHEN POSSIBLE AND CHOOSE
CLEANING AGENTS THAT
CAN BE RECYCLED
BMP #5
STORM DRAIN
SYSTEM SIGNS
MONTHLY -TRAINING OF LANDOWNER
-INSPECT STORM DRAIN INLET
SIGNAGE/STENCILING FOR LEGIBILITY
BMP #6
SOLID WASTE
MANAGMENT
WEEKLY -TRAINING OF LANDOWNER
-INSPECT TRASH ENCLOSURE AREA REGULARLY
-ARRANGE FOR REGULAR WASTE COLLECTION
ATTACHMENT 4
Copy of Plan Sheets Showing Permanent Storm Water BMPs
This is the cover sheet for Attachment 4.
Page intentionally left blank for double‐sided printing
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. Photocopies of general brochures are not acceptable.
Page intentionally left blank for double‐sided printing
REF.REF.
DW
FD
REF.
DW
FD
REF.
DW
FD
REF.
DW
DW
FD
REF.
DWDWDW
FS
SD
SD
SD
SD
WS
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
K ETTLER EWECKL
ENGINEERING
Project
TH
E
P
I
C
T
O
R
I
A
L
A
N
D
G
R
A
P
H
I
C
E
X
P
R
E
S
S
I
O
N
S
D
I
S
P
L
A
Y
E
D
W
I
T
H
T
H
I
S
W
O
R
K
A
R
E
C
O
P
Y
R
I
G
H
T
E
D
U
N
D
E
R
T
H
E
L
A
W
S
O
F
T
H
E
U
N
I
T
E
D
S
T
A
T
E
S
,
T
I
T
L
E
1
7
,
U
.
S
.
C
O
D
E
.
U
N
D
E
R
S
E
C
T
I
O
N
1
0
6
O
F
T
H
E
C
O
P
Y
R
I
G
H
T
A
C
T
,
T
H
E
A
R
C
H
I
T
E
C
T
S
H
A
L
L
M
A
I
N
T
A
I
N
T
H
E
E
X
C
L
U
S
I
V
E
R
I
G
H
T
O
F
T
H
E
R
E
P
R
O
D
U
C
T
I
O
N
,
D
I
S
P
L
A
Y
O
R
A
N
Y
D
E
R
I
V
A
T
I
O
N
OF
T
H
I
S
W
O
R
K
.
17-123
10/10/18 Design Review
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
31
0
-
3
1
6
K
S
t
r
e
e
t
,
C
h
u
l
a
V
i
s
t
a
,
C
A
9
1
9
1
1
31
0
-
3
1
6
K
S
t
r
e
e
t
2/11/19 Design Review 2
4/23/19 Design Review 3
5/31/19 Design Review 4
Proposed
Condition Plan
C2.0
303 A STREET, SUITE 302
SAN DIEGO, CA 92101
t: 619 269-3444 | f: 619 269-3459
www.kettlerleweck.com
K ETTLER EWECKL
ENGINEERING
Project
TH
E
P
I
C
T
O
R
I
A
L
A
N
D
G
R
A
P
H
I
C
E
X
P
R
E
S
S
I
O
N
S
D
I
S
P
L
A
Y
E
D
W
I
T
H
T
H
I
S
W
O
R
K
A
R
E
C
O
P
Y
R
I
G
H
T
E
D
U
N
D
E
R
T
H
E
L
A
W
S
O
F
T
H
E
U
N
I
T
E
D
S
T
A
T
E
S
,
T
I
T
L
E
1
7
,
U
.
S
.
C
O
D
E
.
U
N
D
E
R
S
E
C
T
I
O
N
1
0
6
O
F
T
H
E
C
O
P
Y
R
I
G
H
T
A
C
T
,
T
H
E
A
R
C
H
I
T
E
C
T
S
H
A
L
L
M
A
I
N
T
A
I
N
T
H
E
E
X
C
L
U
S
I
V
E
R
I
G
H
T
O
F
T
H
E
R
E
P
R
O
D
U
C
T
I
O
N
,
D
I
S
P
L
A
Y
O
R
A
N
Y
D
E
R
I
V
A
T
I
O
N
OF
T
H
I
S
W
O
R
K
.
17-123
10/10/18 Design Review
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
Fl
o
i
t
P
r
o
p
e
r
t
i
e
s
31
0
-
3
1
6
K
S
t
r
e
e
t
,
C
h
u
l
a
V
i
s
t
a
,
C
A
9
1
9
1
1
31
0
-
3
1
6
K
S
t
r
e
e
t
2/11/19 Design Review 2
4/23/19 Design Review 3
5/31/19 Design Review 4
Details
C5.0
ATTACHMENT 5
Copy of Project's Drainage Report
Page intentionally left blank for double‐sided printing
FOR REVIEW ONLY
DRAINAGE STUDY
FOR
310-316 K STREET
(DESIGN REVIEW 17-123)
October 10, 2018
Wayne W. Chang, MS, PE 46548
Chang
Civil Engineering ◦ Hydrology ◦ Hydraulics ◦ Sedimentation
P.O. Box 9496
Rancho Santa Fe, CA 92067
(858) 692-0760
FOR REVIEW ONLY
TABLE OF CONTENTS
Introduction ........................................................................................................................................1
Hydrologic Analyses ..........................................................................................................................2
Conclusion .........................................................................................................................................2
APPENDIX
A. Rational Method Data and Results
1
INTRODUCTION
The 310-316 K Street project is a proposed apartment project located at 310-316 K Street in the
city of Chula Vista (see the Vicinity Map). The site covers 1.21 acres and is currently fully
developed with an auto body repair shop surrounded by a paved vehicle storage area. There is
minimal landscaping at the site.
The design review drawings are being prepared by Kettler-Leweck Engineering. The project
consists of one building situated on two parcels on K Street in the city of Chula Vista. The
building will have 4 stories containing 46 dwelling units and a communal area on the first floor.
The site will also include landscaped areas, surface parking and amenities such as a community
room, an elevator, and a separate trash collection area.
2
Under existing conditions, on-site storm runoff sheet flows over impervious surfaces to the
southwesterly corner of the site, and then discharges onto adjacent property. Under proposed
conditions, the on-site storm runoff will be conveyed by private drainage facilities to one of two
Bio Clean Environmental Services, Inc. Modular Wetland System (MWS) Linear BMPs for
pollutant control. The overall on-site drainage area will not be altered by the project. The treated
runoff will then be pumped north to K Street, where it will be conveyed by the K Street curb,
gutter, and pavement. The existing and proposed condition runoff ultimately flows to the same
location west of the site. The project will increase the amount of pervious areas, so will reduce
the site runoff.
HYDROLOGIC ANALYSES
The City of Chula Vista’s 2012 Subdivision Manual rational method procedure was used for the
hydrologic analyses. The existing and proposed condition rational method input parameters are
summarized as follows:
Precipitation: The 100-year, 6- and 24-hour precipitation values are 2.66 and 4.60 inches,
respectively. The isopluvials are included in Appendix A.
Drainage areas: The overall existing condition drainage area matches the overall proposed
condition drainage area and is 2.14 acres. The existing condition analysis contains a single
subarea, while the proposed condition analysis contains multiple subareas. The Existing
Condition Rational Method Work Map and Proposed Condition Rational Method Work
Map are included in Appendix A.
Runoff coefficients: The existing condition runoff coefficient was set at 0.90 since the
majority of the site contains a building and pavement, which are impervious. This is
associated with paved areas according to the Subdivision Manual. The proposed condition
runoff coefficient was set at 0.75, which reflects dense residential development according to
the Subdivision Manual.
Flow lengths and elevations: Flow lengths and elevations were digitized and obtained from
the topographic mapping and the project plans. The existing condition flow length was
selected to be the flow path from the northerly to southerly project boundary although the
flow eventually leaves the southwest corner of the site. The proposed condition flow path
from node 16 to 18 will be conveyed by a pump.
The 100-year existing and proposed condition rational method results are in Appendix A. The
analyses were performed using CivilDesign’s Chula Vista Rational Hydrology Program. The
results show that the existing and proposed condition flow rates are 6.0 and 5.2 cubic feet per
second, respectively.
CONCLUSION
Hydrologic analyses have been performed for the 310-316 K Street project being designed by
Kettler-Leweck Engineering for a design review submittal. The site is currently fully developed
3
with impervious surfaces (building and pavement). The proposed project will increase the
pervious area by adding landscaping. The analyses show that the project will slightly decrease
the 100-year flow rate due to the added pervious surfaces.
APPENDIX A
RATIONAL METHOD
DATA AND RESULTS
SITE
SITE
SUBDIVISION MANUAL
SECTION 3: GENERAL DESIGN CRITERIA
Section 3-200 Page 5
Revised 03-13-2012
3-203 Hydrology
Developers draining to a river or stream will be required to use the latest adopted County
Hydrology Manual to determine the flows expected at a given frequency (Q10, Q50
Q100, etc,) Infill developments will use the following Hydrology requirements. The City
Engineer will determine which projects may be considered "infill" projects.
3-203.1 Previously Approved Reports
Runoff quantities; as set forth or derived from the report prepared by Lawrence,
Fogg, Florer and Smith titled "A Special Study of Storm Drain Facilities" on file
in the office of the City Engineer may be used in the design of drainage
facilities in Chula Vista. A hydrologic study prepared and approved at General
Development Plan (GDP) or Specific Planning Area (SPA) plan may be used
as determined by the City Engineer.
3-203.2
For local drainage basins, storm discharge flow may be estimated based on
the Rational Method or the Modified Rational Method. For all lateral and major
drainage basins the SCS method, U.S. Army Corps of Engineers HEC-1
computer method or other tabular or computer method may be used upon City
Engineer approval.
3-203.3 Rational and Modified Rational Methods
(1) The rational method equation relates storm rainfall intensity (I), a selected
runoff coefficient (C) and drainage area (A) to the peak runoff rate (Q):
where:
Or
where:
Q =CIA (Empirical Units)
Q = Peak runoff in cubic feet per second
C = Runoff coefficient
I = lnten.sity, inches per hours
A = Drainage basin area in acres
Q=0.278CIA (Metric Units)
Q = Peak runoff in cubic meters per second
C = Runoff coefficient
I = Intensity in millimeters per second
A = Drainage area in square kilometers
(2) Coefficient of Runoff: Consider probable development. Use highest number of
the following values:
a)
b)
c)
Paved Surface
Commercial Area
Dense Residential (R2, R3)
0.90
0.85
0.75
NOTES:
SUBDIVISION MANUAL
SECTION 3: GENERAL DESIGN CRITERIA
d)
e)
f)
g)
h)
i)
j)
k)
I)
m)
n)
o)
Normal Residential (R 1)
Suburban Property (RE)
Barren Slopes Steep
Barren Slopes Hilly
" " Rolling
" " Flat
Vegetated Slopes Steep
" " Hilly
" " Rolling
" " Flat
Farm Land
Parks, Golf Courses
Section 3-200 Page 6
Revised 03-13-2012
0.65
0.55
0.80
0.75
0.70
0.65
0.60
0.55
0.50
0.45
0.35
0.30
Steep=
Hilly=
Rolling=
Flat=
Composite=
Steep, rugged terrain with average slopes generally above 30%.
Hilly terrain with average slopes of 10% to 30%.
Rolling terrain with average slopes of 5% to 10%.
Relatively flat land, with average slopes of 0% to 5%.
Where drainage areas are composed of parts having different
runoff characteristics, a weighted coefficient for the total
drainage area may be used.
The runoff coefficient for a basin should be a composite coefficient made of the many
different runoff coefficients for the sub-areas of the basin per equation:
CAr = C 1 A 1 +C~2+ ... CnAn --------
n
(3) Time of Concentration (le= minutes) is the time required for runoff to flow from
the most remote part of the watershed to the outlet point under consideration.
With exceptions for limited natural watersheds, the time of concentration shall
be calculated as follows:
a) where:
t; = Initial time or overland flow time of concentration, the time
required for runoff to flow to the first inlet or to the street
gutter
t, = Travel time of concentration, the time required for runoff to
flow within street gutters to inlets, with channels or within
storm drain pipes.
b) t; may be calculated using the following natural watershed flow
formula:
l; = 60x [(11.9L3)/H]0385
L = Length of water shed (miles)
H = Difference in elevation from furthermost point to the design
point (feet).
1
City of Chula Vista Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1992-2007 Version 7.2
Rational Hydrology Study Date: 10/07/18
------------------------------------------------------------------------
310-316 K Street
Design Review
Existing Conditions
100-Year Storm Event
------------------------------------------------------------------------
********* Hydrology Study Control Information **********
------------------------------------------------------------------------
Program License Serial Number 4028
------------------------------------------------------------------------
Rational hydrology study storm event year is 100.0
Map data precipitation entered:
6 hour, precipitation(inches) = 2.660
24 hour precipitation(inches) = 4.600
Adjusted 6 hour precipitation (inches) = 2.660
P6/P24 = 57.8%
Runoff values by rational method
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 12.000
**** INITIAL AREA EVALUATION ****
______________________________________________________________________
[PAVED SURFACE area type ]
Initial subarea flow distance = 299.000(Ft.)
Highest elevation = 101.500(Ft.)
Lowest elevation = 99.000(Ft.)
Elevation difference = 2.500(Ft.)
Time of concentration calculated by Page 12 Section 3-400
developed areas with overland flow = 6.61 min.
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.9000)*( 299.000^.5)/( 0.836^(1/3)]= 6.61
Rainfall intensity I = 7.44P6*TC^-0.645):
I = 7.44(6.608)( 2.660)^-0.645:
Intensity = 5.855(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.900
Subarea runoff = 6.007(CFS)
Total initial stream area = 1.140(Ac.)
End of computations, total study area = 1.140 (Ac.)
1
City of Chula Vista Rational Hydrology Program
CIVILCADD/CIVILDESIGN Engineering Software, (c) 1992-2007 Version 7.2
Rational Hydrology Study Date: 10/07/18
------------------------------------------------------------------------
310-316 K Street
Design Review
Proposed Conditions
100-Year Storm Event
------------------------------------------------------------------------
********* Hydrology Study Control Information **********
------------------------------------------------------------------------
Program License Serial Number 4028
------------------------------------------------------------------------
Rational hydrology study storm event year is 100.0
Map data precipitation entered:
6 hour, precipitation(inches) = 2.660
24 hour precipitation(inches) = 4.600
Adjusted 6 hour precipitation (inches) = 2.660
P6/P24 = 57.8%
Runoff values by rational method
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 10.000 to Point/Station 12.000
**** INITIAL AREA EVALUATION ****
______________________________________________________________________
[DENSE RESIDENTIAL area type (R-2, R-3) ]
Initial subarea flow distance = 52.000(Ft.)
Highest elevation = 102.000(Ft.)
Lowest elevation = 101.000(Ft.)
Elevation difference = 1.000(Ft.)
Time of concentration calculated by Page 12 Section 3-400
developed areas with overland flow = 3.65 min.
TC = [1.8*(1.1-C)*distance(Ft.)^.5)/(% slope^(1/3)]
TC = [1.8*(1.1-0.7500)*( 52.000^.5)/( 1.923^(1/3)]= 3.65
Setting time of concentration to 5 minutes
Rainfall intensity I = 7.44P6*TC^-0.645):
I = 7.44(5.000)( 2.660)^-0.645:
Intensity = 7.008(In/Hr) for a 100.0 year storm
Effective runoff coefficient used for area (Q=KCIA) is C = 0.750
Subarea runoff = 0.421(CFS)
Total initial stream area = 0.080(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 12.000 to Point/Station 14.000
2
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
______________________________________________________________________
Upstream point/station elevation = 101.00(Ft.)
Downstream point/station elevation = 99.35(Ft.)
Pipe length = 165.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 0.421(CFS)
Nearest computed pipe diameter = 6.00(In.)
Calculated individual pipe flow = 0.421(CFS)
Normal flow depth in pipe = 3.88(In.)
Flow top width inside pipe = 5.74(In.)
Critical Depth = 3.96(In.)
Pipe flow velocity = 3.14(Ft/s)
Travel time through pipe = 0.88 min.
Time of concentration (TC) = 5.88 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 14.000 to Point/Station 14.000
**** SUBAREA FLOW ADDITION ****
______________________________________________________________________
[DENSE RESIDENTIAL area type (R-2, R-3) ]
Time of concentration = 5.88 min.
Rainfall intensity = 6.315(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.750
Subarea runoff = 0.853(CFS) for 0.180(Ac.)
Total runoff = 1.273(CFS) Total area = 0.26(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 14.000 to Point/Station 16.000
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
______________________________________________________________________
Upstream point/station elevation = 99.35(Ft.)
Downstream point/station elevation = 97.85(Ft.)
Pipe length = 148.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 1.273(CFS)
Nearest computed pipe diameter = 9.00(In.)
Calculated individual pipe flow = 1.273(CFS)
Normal flow depth in pipe = 5.89(In.)
Flow top width inside pipe = 8.56(In.)
Critical Depth = 6.24(In.)
Pipe flow velocity = 4.15(Ft/s)
Travel time through pipe = 0.59 min.
Time of concentration (TC) = 6.47 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 16.000 to Point/Station 16.000
**** SUBAREA FLOW ADDITION ****
______________________________________________________________________
[DENSE RESIDENTIAL area type (R-2, R-3) ]
Time of concentration = 6.47 min.
3
Rainfall intensity = 5.935(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.750
Subarea runoff = 3.739(CFS) for 0.840(Ac.)
Total runoff = 5.012(CFS) Total area = 1.10(Ac.)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 16.000 to Point/Station 18.000
**** PIPEFLOW TRAVEL TIME (Program estimated size) ****
______________________________________________________________________
Upstream point/station elevation = 97.85(Ft.)
Downstream point/station elevation = 94.85(Ft.)
Pipe length = 284.00(Ft.) Manning's N = 0.013
No. of pipes = 1 Required pipe flow = 5.012(CFS)
Nearest computed pipe diameter = 15.00(In.)
Calculated individual pipe flow = 5.012(CFS)
Normal flow depth in pipe = 9.74(In.)
Flow top width inside pipe = 14.32(In.)
Critical Depth = 10.89(In.)
Pipe flow velocity = 5.95(Ft/s)
Travel time through pipe = 0.80 min.
Time of concentration (TC) = 7.27 min.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
Process from Point/Station 18.000 to Point/Station 18.000
**** SUBAREA FLOW ADDITION ****
______________________________________________________________________
[DENSE RESIDENTIAL area type (R-2, R-3) ]
Time of concentration = 7.27 min.
Rainfall intensity = 5.507(In/Hr) for a 100.0 year storm
Runoff coefficient used for sub-area, Rational method,Q=KCIA, C = 0.750
Subarea runoff = 0.165(CFS) for 0.040(Ac.)
Total runoff = 5.177(CFS) Total area = 1.14(Ac.)
End of computations, total study area = 1.140 (Ac.)
Page intentionally left blank for double‐sided printing
ATTACHMENT 6
Copy of 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.
Page intentionally left blank for double‐sided printing
PRELIMINARY GEOTECHNICAL INVESTIGATION
PROPOSED 44-UNIT RESIDENTIAL DEVELOPMENT
310-316 K STREET, CHULA VISTA
SAN DIEG O C OU NTY, CA LIFO RN IA
APN(s) 573-450-05-00 & 573-450-04-00
FOR
QUINN COMMUNITIES
364 2 STREET, #5ND
ENCINITAS, CALIFORNIA 92024
W.O. 7393-A-SC FEBRUARY 23, 2018
Geotechnical C Geologic C Coastal C Environmental
5741 Palmer Way C Carlsbad, California 92010 C (760) 438-3155 C FAX (760) 931-0915 C www.geosoilsinc.com
February 23, 2018
W.O. 7393-A-SC
Quinn Communities
364 2 Street, #5nd
Encinitas, California 92024
Attention:Mr. Stefan LaCasse
Subject:Preliminary Geotechnical Investigation, Proposed 44-Unit Residential
Development, 310-316 K Street, Chula Vista, San Diego County, California,
APN(s) 573-450-05-00 & 573-450-04-00
Dear Mr. LaCasse:
In accordance with your request and authorization, GeoSoils, Inc. (GSI) has performed a
preliminary geotechnical investigation of the subject site relative to the proposed
multi-family residential development thereon. The primary purpose of this study was to
evaluate the onsite geologic and geotechnical conditions for project feasibility and to
provide preliminary recommendations for earthwork, and the design and construction of
foundations, retaining walls, and pavements.
EXECUTIVE SUMMARY
Based on our review of the available data (see Appendix A), field exploration, laboratory
testing, and geologic and engineering analysis, the proposed development of the property
appears to be feasible from a geotechnical perspective, provided the recommendations
presented in the text of this report are properly incorporated into the design and
construction of the project. The most significant findings of our study are summarized
below:
•Based on a review of conceptual architectural plans prepared by Studio E Architects
([Studio], 2017) and clients’ communication, the proposed three-story residential
development consists of 44 units, that includes a mixture of one-, two-, and
three-bedroom units distributed throughout building, with a pool, common area,
and surface level parking (66 spaces).
•Earth materials encountered within the property during our field investigation,
include localized undocumented fill and Quaternary-age, old paralic deposits.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
File:wp12\7300\7393a.pgi Page Two
•In their existing state, earth materials considered unsuitable for the support of
settlement-sensitive improvements (i.e., the structure, underground utilities, walls,
hardscape, pavements, etc.) and/or planned engineered fills consist of existing
undocumented artificial fill and the near-surface old paralic deposits to a depth of
approximately 3 to 5 feet below the existing ground surface (BEGS).
Recommendations for remedial grading and the preliminary design of foundations
and pavements are provided herein. This report also discusses other possible
remedial earthwork alternatives for the mitigation of moderately expansive
near-surface earth materials (if encountered during grading).
•It should be noted, that the 2016 California Building Code ([2016 CBC], California
Building Standards Commission [CBSC], 2016) indicates that the mitigation of
unsuitable soils be performed across all areas of the site covered under a grading
permit and not just within the influence of the proposed multi-family structure.
Relatively deep removals may necessitate a special zone of consideration, on
perimeter/confining areas. This zone would be approximately equal to the depth
of removals, if removals cannot be performed onsite and offsite. For this site, the
width of this zone is anticipated to be 3 to 6 feet, based on the available
data and the remedial earthwork recommendations contained herein. Any
settlement-sensitive improvement constructed within this zone, may require
deepened foundations, reinforcements, etc., or will retain some potential for
settlement and associated distress. This will require proper disclosure to all
interested/affected parties, should this condition exist at the conclusion of grading.
•On a preliminary basis, temporary excavations greater than 4 feet, but less than
20 feet in overall height, performed into the onsite earth materials, should conform
to CAL-OSHA and/or OSHA requirements for Type “D” soils provided that
groundwater, running sands, or other adverse geologic conditions are absent.
All temporary excavations should be observed by a licensed engineering geologist
or geotechnical engineer prior to worker entry. Although not anticipated, based on
the available data, if temporary slopes conflict with property boundaries and/or
existing improvements that need to remain in serviceable use both during and
following site development, shoring or alternating slot excavations may be
necessary. The need for shoring or alternating slot excavations should be further
evaluated during the grading plan review stage.
•Expansion index (E.I.) testing, performed on representative samples of the
near-surface earth materials, indicated an E.I. of 5 to 15, and correlates to a “very
low” expansion potential. Atterberg Limits testing, performed on representative
samples of the near-surface earth materials indicated a plasticity index (P.I.) of 17.
Equivalent to a low expansive E.I. The results of our laboratory testing indicate that
some near-surface, onsite earth materials may meet the criteria for detrimentally
expansive soils, as defined in Section 1803.5.3 of the 2016 CBC (CBSC, 2016). The
possibility of encountering expansive soils during grading cannot be precluded and
conventional foundation design may not be adequate, therefore, preliminary
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
File:wp12\7300\7393a.pge Page Three
geotechnical recommendations for the design of post-tensioned foundation and
mat foundation systems are also provided herein.
•Laboratory testing indicates that tested sample of the onsite soil is neutral with
respect to soil acidity/alkalinity; is severely corrosive to exposed, buried metals
when saturated; present negligible (“not applicable” per American Concrete
Institute [ACI] 318-14) sulfate exposure to concrete (i.e., Exposure Class S0 per
Table 19.3.1.1 of ACI 318-14); and has relatively low concentrations of soluble
chlorides. It should be noted that GSI does not consult in the field of corrosion
engineering. Therefore, additional comments and recommendations may be
obtained from a qualified corrosion engineer based on the level of corrosion
protection required for the project, as determined by the project architect, civil
engineering, and/or structural engineer.
•Regional groundwater was not encountered to the depths explored in this
investigation, and is not anticipated to significantly affect the planned
improvements. However, due to the nature of site earth materials, there is a
potential for perched water to occur both during and following site development.
This potential should be disclosed to all interested/affected parties. Should perched
water conditions be encountered, this office could provide recommendations for
mitigation. Typical mitigation includes subdrainage system, cut-off barriers, etc.
•In early 2016, the City of Chula Vista adopted State of California Regional Water
Quality Control Board requirements for the onsite treatment of storm water by
means of infiltration for priority development projects (PDPs). Due to the dense to
very dense nature of the soils at the site and surrounding vicinity, and closed
proximity to existing and proposed structures, GSI does not recommend storm
water infiltration (full or partial) at the subject site. The infiltration of storm water
could damage both onsite and offsite improvements.
•Due to the very gentle topographic relief and the absence of any significant nearby
slopes, the site has low susceptibility to deep-seated landslides.
•Owing to the depth to groundwater and the dense nature of the formational
materials, the potential for the site to be adversely affected by liquefaction/lateral
spreading is considered very low. The lateral consistency of the offsite geologic
conditions is unknown, but it is likely that there is lateral continuity on adjoining
properties.
•Site soils are considered erosive. Thus, properly designed site drainage is
necessary in reducing erosion damage to the planned improvements.
•Our evaluation indicates there are no known active faults crossing the site. Thus,
the potential for surface fault rupture is considered low.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
File:wp12\7300\7393a.pgi Page Four
•The seismic acceleration values and design parameters provided herein should be
considered during the design of the proposed development. The adverse effects
of seismic shaking on the structure(s) will likely be wall cracks, some
foundation/slab distress, and some seismic settlement. However, it is anticipated
that the structure will be repairable in the event of the design seismic event. This
potential should be disclosed to all interested/affected parties.
•Adverse geologic features that would preclude project feasibility were not
encountered.
•The recommendations presented in this report should be incorporated into the
design and construction considerations of the project.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
File:wp12\7300\7393a.pge Page Five
The opportunity to be of service is sincerely appreciated. If you should have any
questions, please do not hesitate to contact our office.
Respectfully submitted,
GeoSoils, Inc.
John P. Franklin David W. Skelly
Engineering Geologist, CEG 1340 Civil Engineer, RCE 47857
Charles W. Parrish
Staff Geologist
CWP/RGC/JPF/DWS/jh
Distribution:(2) Addressee (wet signed/stamp and email)
GeoSoils, Inc.
TABLE OF CONTENTS
SCOPE OF SERVICES ...................................................4
SITE DESCRIPTION AND PROPOSED DEVELOPMENT .........................4
SITE EXPLORATION .....................................................6
REGIONAL GEOLOGY ...................................................6
Regional Geologic Setting ...........................................6
SITE GEOLOGIC UNITS ..................................................7
Artificial Fill - Undocumented (Map Symbol - Afu)........................7
Quaternary-Age Old Paralic Deposits (Map Symbol - Qop).................7
GEOLOGIC STRUCTURE .................................................8
GROUNDWATER ........................................................8
GEOLOGIC/SEISMIC HAZARDS EVALUATION ................................8
Mass Wasting/Landslide Susceptibility .................................8
Faulting ..........................................................9
Local and Regional Faults......................................9
Surface Fault Rupture .........................................9
Regional Seismicity ...............................................10
General ...................................................10
Deterministic Maximum Credible Site Acceleration .................10
Historical Site Acceleration ....................................10
Seismic Shaking Parameters ........................................11
LIQUEFACTION POTENTIAL .............................................12
Liquefaction .....................................................12
Seismic Densification ..............................................13
Summary........................................................13
Other Geologic/Secondary Seismic Hazards ...........................13
LABORATORY TESTING .................................................14
General .........................................................14
Classification .....................................................14
Moisture-Density Relations .........................................14
Laboratory Standard...............................................14
Expansion Potential ...............................................14
Atterberg Limits...................................................15
Direct Shear .....................................................15
Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides .............15
Corrosion Summary .........................................16
GeoSoils, Inc.
Quinn Communities Tab le of C ontents
File:wp12\7300\7392a.pgi Pa ge ii
STORM WATER INFILTRATION RATE EVALUATION AND DISCUSSION ..........16
Subsurface Exploration ............................................16
USDA Study .....................................................16
Infiltration Feasibility ...............................................17
Onsite Filtration/Infiltration-Runoff Retention Systems ....................18
PRELIMINARY CONCLUSIONS ...........................................20
EARTHWORK CONSTRUCTION RECOMMENDATIONS .......................23
Removal and Recompaction of Potentially Compressible Earth Materials ....23
Perimeter Conditions ..............................................23
Fill Placement ....................................................24
Overexcavation ...................................................24
Temporary Slopes ................................................24
OTHER EARTHWORK CRITERIA ..........................................25
Expansive Soil Mitigation/Selective Grading Considerations ...............25
Import Soils ......................................................25
Graded Slope Construction .........................................25
Stabilization Fills/Slope Drainage ....................................26
Excavation Observation and Monitoring (All Excavations).................26
Observation ................................................27
Earthwork Balance (Shrinkage/Bulking)...............................27
PRELIMINARY RECOMMENDATIONS - FOUNDATIONS .......................27
General .........................................................27
Preliminary Foundation Design ......................................28
PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS ...........29
Conventional Foundation and Slab-On-Grade Floor Systems ..............29
Post-Tensioned Foundations ........................................30
Slab Subgrade Pre-Soaking ...................................31
Perimeter Cut-Off Walls .......................................32
Post-Tensioned Foundation Design .............................32
Soil Support Parameters ......................................32
Foundation Settlement .............................................34
SOIL MOISTURE TRANSMISSION CONSIDERATIONS ........................34
WALL DESIGN PARAMETERS ............................................36
Conventional Retaining Walls .......................................36
Restrained Walls ............................................36
Cantilevered Walls ...........................................37
Seismic Surcharge ................................................37
GeoSoils, Inc.
Quinn Communities Tab le of C ontents
File:wp12\7300\7392a.pgi Pa ge iii
Retaining Wall Backfill and Drainage ..................................38
Wall/Retaining Wall Footing Transitions ...............................42
TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS ......42
Slope Creep .....................................................42
Top of Slope Walls/Fences .........................................43
DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS .......................44
DEVELOPMENT CRITERIA ...............................................46
Planting .........................................................46
Drainage ........................................................46
Erosion Control...................................................47
Landscape Maintenance and Planter Design ...........................47
Gutters and Downspouts ...........................................47
Subsurface and Surface Water ......................................47
Site Improvements ................................................48
Footing Trench Excavation .........................................48
Trenching/Temporary Construction Backcuts ..........................48
SUMMARY OF RECOMMENDATIONS REGARDING GEOTECHNICAL OBSERVATION AND
TESTING ........................................................49
OTHER DESIGN PROFESSIONALS/CONSULTANTS ..........................49
PLAN REVIEW .........................................................50
LIMITATIONS ..........................................................50
FIGURES:
Figure 1 - Site Location Map .........................................2
Detail 1 - Typical Retaining Wall Backfill and Drainage Detail ..............39
Detail 2 - Retaining Wall Backfill and Subdrain Detail Geotextile Drain .......40
Detail 3 - Retaining Wall and Subdrain Detail Clean Sand Backfill ...........41
ATTACHMENTS:
Plate 1 - Geotechnical Map .................................Rear of Text
Appendix A - References ...................................Rear of Text
Appendix B - Boring Logs ..................................Rear of Text
Appendix C - Seismicity ....................................Rear of Text
Appendix D - Laboratory Data ...............................Rear of Text
Appendix E - Infiltration Test Data Sheets ......................Rear of Text
Appendix F - Worksheets C.4-1 and D.5-1 .....................Rear of Text
Appendix G - General Earthwork, Grading Guidelines, and Preliminary Criteria
..................................................Rear of Text
GeoSoils, Inc.
PRELIMINARY GEOTECHNICAL INVESTIGATION
PROPOSED 44-UNIT RESIDENTIAL DEVELOPMENT
310-316 K STREET, CHULA VISTA
SAN DIEGO COUNTY, CALIFORNIA
APN(s) 573-450-05-00 & 573-450-04-00
SCOPE OF SERVICES
The scope of our services has included the following:
1.Review of available geologic literature, regional geologic maps, and aerial
photographs of the site and near vicinity (see Appendix A).
2.Geologic site reconnaissance, mapping, and subsurface exploration with two (2)
hollow-stem auger borings (see Appendix B).
3.Advance two (2) hollow-stem auger borings to a depth of approximately 5 feet, for
the purpose of obtaining a site specific infiltration rates.
4.General geologic hazard and a real seismicity evaluation (see Appendix C).
5.Appropriate laboratory testing of representative soil samples (Appendix D).
6.Engineering and geologic analysis of data collected.
7.Preparation of this summary report and accompaniments, including
recommendations for site work and foundation design/construction.
SITE DESCRIPTION AND PROPOSED DEVELOPMENT
The property is located on the south side of K Street approximately 150 feet west of the
intersection with Third Avenue in the City of Chula Vista, County of San Diego, California
(see Figure 1, Site Location Map). The site is bordered to the north by K Street, the south
by a bank and associated parking lot, the east by a fast food restaurant, and the west by
multi-family residential dwellings. Currently the property is composed of two parcels,
containing the Marquez Auto Body shop. It is covered by asphalt and concrete
surrounding the buildings.
Based on a review of Google Earth, topographically the site is mostly flat, with site
elevations ranging from approximately 99 feet MSL along the northern property line to
approximately 101 feet mean sea level (MSL) along the southern property line. Based on
a review of the conceptual architectural plans by Studio E Architects (Studio, 2017) and the
clients’ communication, the proposed three-story residential development consists of
44 units, that includes a mixture of one-, two-, and three-bedroom units distributed
throughout building, with a pool, common area, and surface level parking (66 spaces).
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 6
SITE EXPLORATION
Field exploration, performed in conjunction with this study, was conducted on January 25th
and 26 , 2018, and consisted of advancing two (2) deep hollow-stem auger borings for theth
purpose of evaluating the underlying geologic units, and two (2) shallow hollow-stem
auger borings for infiltration testing. The borings were logged by a representative of this
office who collected representative bulk and relatively undisturbed soil samples for
appropriate laboratory testing. The logs of the borings are presented in Appendix B. Site
geology and the location of the borings are shown on the Geotechnical Map (see Plate 1),
which uses the conceptual site plan provided by Studio (2017) as a base.
REGIONAL GEOLOGY
Regional Geologic Setting
San Diego County lies within the Peninsular Ranges Geomorphic Province of southern
California. This province is characterized as elongated mountain ranges and valleys that
trend northwesterly (Norris and Webb, 1990). This geomorphic province extends from the
base of the east-west aligned Santa Monica - San Gabriel Mountains, and continues south
into Baja California, Mexico. The mountain ranges within this province are underlain by
basement rocks consisting of pre-Cretaceous metasedimentary rocks, Jurassic
metavolcanic rocks, and Cretaceous plutonic (granitic) rocks.
The San Diego County region was originally a broad area composed of pre-batholithic
rocks that were subsequently subjected to tectonism and metamorphism. In the late
Cretaceous Period, the southern California Batholith was emplaced causing the
aforementioned metamorphism of pre-batholithic rocks. Many separate magmatic
injections originating from this body occurred along zones of structural weakness.
Following batholith emplacement, uplift occurred, resulting in the removal of the overlying
rocks by erosion. Erosion continued until the area was that of low relief and highly
weathered. The eroded materials were deposited along the sea margins. Sedimentation
also occurred during the late Cretaceous Period. However, subsequent erosion has
removed much of this evidence. In the early Tertiary Period, terrestrial sedimentation
occurred on a low-relief land surface. In Eocene time, previously fluctuating sea levels
stabilized and marine deposition occurred. In the late Eocene, regional uplift produced
erosion and thick deposition of terrestrial sediments. In the middle Miocene, the
submergence of the Los Angeles Basin resulted in the deposition of thick marine beds in
the northwestern portion of San Diego County. During the Pliocene, marine sedimentation
was more discontinuous and generally occurred within shallow marine embayments. The
Pleistocene saw regressive and transgressive sea levels that fluctuated with prograding
and recessive glaciation. The changes in sea level had a significant effect on coastal
topography and resultant wave erosion and deposition formed many terraces along the
coastal plain. In the mid-Pleistocene, regional faulting separated highland erosional
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 7
surfaces into major blocks lying at varying elevations. A later rise in sea level during the
late Pleistocene, caused the deposition of thick alluvial deposits within the coastal river
channels. In recent geologic time, crystalline rocks have weathered to form soil residuum,
highland areas have eroded, and deposition of river, lake, lagoonal, and beach sediments
has occurred.
Regional geologic mapping by Kennedy and Tan (2008) indicates that the northernmost
portion of the site is underlain by Quaternary-age very old paralic deposits (formerly termed
“Lindavista Formation” on older geologic maps), and remainder of the site (southern
portion) is mapped as being underlain by Quaternary-age old paralic deposits. For the
purposes of this report the Quaternary-age very old paralic deposits and Quaternary old
paralic deposits, are undifferentiated and will be referred to as old paralic deposits.
SITE GEOLOGIC UNITS
The site geologic units encountered during our subsurface investigation and site
reconnaissance included localized undocumented artificial fill and old paralic deposits.
The earth materials are generally described below from the youngest to the oldest. The
distribution of these materials across the site is shown on Plate 1.
Artificial Fill - Undocumented (Map Symbol - Afu)
Undocumented artificial fill was encountered at the surface in all borings. As observed,
therein, the undocumented fill generally consisted of dark grayish brown to dark reddish
brown, silty sand and clayey sand, that was damp and loose to medium dense; and dark
reddish brown, dark brown, and very dark brown sandy clay that was damp to wet, and stiff
to very stiff, and also contained construction debris (concrete, asphalt, and brick
fragments). The fill was observed to extend to depths on the order of 3 to 5¾ feet BEGS.
The undocumented fill is considered unsuitable for the support of proposed
settlement-sensitive improvements and new fills in its existing state.
Quaternary-Age Old Paralic Deposits (Map Symbol - Qop)
Quaternary-age old paralic deposits were encountered beneath the aforementioned
artificial fill in the two deeper Borings B-1 and B-2, and extended to the total depths of both
borings (60 feet and 40 feet BEGS, respectively). The old paralic deposits consisted of
sandy claystone, claystone, and silty sandstone in the upper approximate 20 to 25 feet and
at depth was a silty sandstone to sandstone. The sandy claystone consisted of dark brown
clay that was moist and very stiff, with fine grained sand; the claystone consisted of dark
brown clay that was moist and very stiff; the silty sandstone consisted of light yellowish,
yellowish brown, and pale yellowish brown to white, was dry to damp, and very dense.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 8
GEOLOGIC STRUCTURE
Kennedy and Tan (2008) show Tertiary San Diego Formation to the southeast, and very
old paralic deposits to the south of the subject site generally strike northwest and dip to
the south/southwest at very gentle inclinations.
GROUNDWATER
GSI did not encounter groundwater during our field exploration, to the depths explored.
Based on a review of an semiannual groundwater monitoring report by Orion
Environmental, Inc. (2016) for a nearby site located at 798 3 Avenue, we conclude thatrd
the regional groundwater table is likely greater than 75 feet BEGS, in the site vicinity.
Groundwater is not expected to be a major factor in site development. However, perched
water seepage may be encountered during planned and remedial excavations. In addition,
due to the nature of the site earth materials, post-development seepage and/or perched
groundwater conditions may develop throughout the site in the future, especially along
boundaries of contrasting permeabilities and densities (i.e., sandy/clayey fill lifts, fill/old
paralic deposit contacts, bedrock discontinuities, etc.), and should be anticipated.
The manifestation of perched water is typically the result of numerous factors including site
geologic conditions, rainfall, irrigation, broken or damaged wet utilities, etc. This potential
should be disclosed to all interested/affected parties. Infiltration for onsite storm water
treatment would increase this potential and also result in distress to improvements, both
onsite and offsite.
Due to the potential for post-development perched water to manifest near the surface,
owing to existing and as-graded permeability contrasts, more onerous slab design is
necessary for any new slab-on-grade floor (State of California, 2018). Recommendations
for reducing the amount of water and/or water vapor through slab-on-grade floors are
provided in the “Soil Moisture Considerations” sections of this report. It should be noted
that these recommendations should be implemented if the transmission of water or water
vapor through the slab is undesirable. Should these mitigative measures not be
implemented, then the potential for water or vapor to pass through the foundations and
slabs and resultant distress cannot be precluded, and would need to be disclosed to all
interested/affected parties.
GEOLOGIC/SEISMIC HAZARDS EVALUATION
Mass Wasting/Landslide Susceptibility
Mass wasting refers to the various processes by which earth materials are moved down
slope in response to the force of gravity. Examples of these processes include slope
creep, surficial failures, and deep-seated landslides. Creep is the slowest form of mass
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 9
wasting and generally involves the outer 5 to 10 feet of a slope surface. During heavy
rains, such as those in El Niño years, creep-affected materials may become saturated,
resulting in a more rapid form of downslope movement (i.e., landslides
and/or surficial failures).
According to regional landslide hazard mapping performed by the State of California
Department of Conservation - Division of Mines and Geology (Tan, 1995), the subject site
is located within Relative Landslide Susceptibility Area 2, which is characterized as being
marginally susceptible to landslides. According to Tan (1995), landslides and other slope
failures in this area are rare, although there is potential for slope hazards on some steeper
slopes within this overall area or along its margins.
Based on our review of regional geologic maps (Kennedy and Tan, 2008; Kennedy and
Peterson, 1975), there is no evidence of landslide debris at the subject site. In addition,
we did not encounter landslide debris during our field explorations, nor did we observe any
geomorphic expressions indicative of significant on-going or past deep-seated instability
or mass wasting events (i.e., scarps, hummocky terrain, landslide debris, etc.). The subject
site is relatively flat-lying and located at a considerable distance from any significant slope
(i.e., more than several hundred feet). Our findings are positive lines of evidence that the
site’s susceptibility to large mass wasting events may be considered low.
Faulting
Local and Regional Faults
Our review indicates that there are no known active faults crossing this site (Jennings and
Bryant, 2010), and the site is not within an Alquist-Priolo Earthquake Fault Zone (California
Geological Survey [CGS], 2018). However, the site is situated in a region of active faulting.
These faults include, but are not limited to: the San Andreas fault; the San Jacinto fault; the
Elsinore fault; the Coronado Bank fault zone; and the Newport-Inglewood - Rose Canyon
fault zone (NIRCFZ). The closest known active fault to the subject site is the Rose Canyon
fault, located at an approximate distance of 7.0 miles (11.2 kilometers). Portions of the
Rose Canyon fault have demonstrated movement in the Holocene Epoch (i.e., last
±11,000 years); and therefore, are considered active and located in an Alquist-Priolo
Earthquake Fault Zone (Bryant and Hart, 2007). Cao, et al. (2003) indicate that
Rose Canyon fault is an “B” fault with a slip rate of 1.5 (±0.5) millimeters per year, and is
wcapable of producing a maximum magnitude (M ) 7.2 earthquake. The location of the
Rose Canyon fault and other major faults that could have an affect on the site through
moderate to strong ground shaking are shown on the “California Fault Map” in
Appendix C.
Surface Fault Rupture
Surface fault rupture is the displacement of the ground surface caused by fault propagation
extending to the surface of the earth’s crust. Since there are no known faults crossing the
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 10
site that have exhibited activity in the last ±11,000 years (Jennings and Bryant, 2010;
CGS, 2018), the potential for surface fault rupture to adversely affect the proposed
development is considered low.
Regional Seismicity
General
The subject site is located within a seismically active region subject to moderate to strong
earthquakes occurring along many active fault splays. The possibility of ground
acceleration or ground shaking at the site, may be considered as approximately similar to
the southern California region as a whole.
Deterministic Maximum Credible Site Acceleration
The acceleration-attenuation relation of Bozorgnia, Campbell, and Niazi (1999) has been
incorporated into EQFAULT (Blake, 2000a). EQFAULT is a computer program developed
by Thomas F. Blake (2000a), which performs deterministic seismic hazard analyses using
digitized California faults as earthquake sources.
The program estimates the closest distance between each fault and a given site. If a fault
is found to be within a user-selected radius, the program estimates peak horizontal ground
acceleration that may occur at the site from an upper bound (formerly “maximum credible
earthquake”), on that fault. Upper bound refers to the maximum expected ground
acceleration produced from a given fault. Based on the EQFAULT program, a peak
horizontal ground acceleration from an upper bound event on the Rose Canyon fault may
be on the order of 0.4575 g. The computer printouts of pertinent portions of the EQFAULT
program are included within Appendix C.
Historical Site Acceleration
Historical site seismicity was evaluated with the acceleration-attenuation relation of
Bozorgnia, Campbell, and Niazi (1999), and the computer program EQSEARCH
(Blake, 2000b). This program performs a search of the historical earthquake records for
magnitude 5.0 to 9.0 seismic events within a 100-kilometer radius, between the
years 1800 through December 15, 2016. Based on the selected acceleration-attenuation
relationship, a peak horizontal ground acceleration is estimated, which may have effected
the site during the specific event listed. Based on the available data and the
acceleration-attenuation relationship used, the estimated maximum (peak) site acceleration
during the period 1800 through December 15, 2016 was 0.205 g. A historic earthquake
epicenter map and a seismic recurrence curve are also estimated/generated from the
historical data. Computer printouts of the EQSEARCH program are presented in
Appendix C.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 11
Seismic Shaking Parameters
Based on the site conditions, the following table summarizes the site-specific design
criteria obtained from the 2016 CBC (CBSC, 2016), Chapter 16 Structural Design,
Section 1613, Earthquake Loads. The computer program “U.S. Seismic Design Maps,”
provided by the United States Geological Survey ([USGS], 2014) was utilized for design.
The short spectral response utilizes a period of 0.2 seconds.
2016 CBC SEISMIC DESIGN PARAMETERS
PARAMETER VALUE 2013 CBC
AND/OR REFERENCE
Site Class D Section 1613.3.2/ASCE 7-10
(Chapter 20)
sSpectral Response - (0.2 sec), S 0.975 g Figure 1613.3.1(1)
1Spectral Response - (1 sec), S 0.370 g Figure 1613.3.1(2)
aSite Coefficient, F 1.110 Table 1613.3.3(1)
vSite Coefficient, F 1.659 Table1613.3.3(2)
Maximum Considered Earthquake Spectral
MSResponse Acceleration (0.2 sec), S 1.083 g Section 1613.3.3
(Eqn 16-37)
Maximum Considered Earthquake Spectral
M1Response Acceleration (1 sec), S 0.614 g Section 1613.3.3
(Eqn 16-38)
5% Damped Design Spectral Response
DSAcceleration (0.2 sec), S 0.722 g Section 1613.3.4
(Eqn 16-39)
5% Damped Design Spectral Response
D1Acceleration (1 sec), S 0.410 g Section 1613.3.4
(Eqn 16-40)
MPGA 0.445 g ASCE 7-10 (Eqn 11.8.1)
Seism ic Design Category D Section 1613.3.5/ASCE 7-10
(Table 11.6-1 or 11.6-2)
GENERAL SEISMIC PARAMETERS
PARAMETER VALUE
Distance to Seismic Source (Rose Canyon fault)7.0 mi (11.2 km)(1)
WUpper B ound Earthquake (Rose Canyon)M = 7.2(2)
- Blake (2000a)(1)
- Cao, et al. (2003)(2)
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 12
Conformance to the criteria above for seismic design does not constitute any kind of
guarantee or assurance that significant structural damage or ground failure will not occur
in the event of a large earthquake. The primary goal of seismic design is to protect life, not
to eliminate all damage, since such design may be economically prohibitive. Cumulative
effects of seismic events are not addressed in the 2016 CBC (CBSC, 2016) and regular
wmaintenance and repair following locally significant seismic events (i.e., M 5.5) will likely
be necessary.
LIQUEFACTION POTENTIAL
Liquefaction
Liquefaction describes a phenomenon in which cyclic stresses, produced by
earthquake-induced ground motion, create excess pore pressures in relatively
cohesionless soils. These soils may thereby acquire a high degree of mobility, which can
lead to vertical deformation, lateral movement, lurching, sliding, and as a result of seismic
loading, volumetric strain and manifestation in surface settlement of loose sediments, sand
boils and other damaging lateral deformations. This phenomenon occurs only below the
water table, but after liquefaction has developed, it can propagate upward into overlying
non-saturated soil as excess pore water dissipates.
One of the primary factors controlling the potential for liquefaction is depth to groundwater.
Typically, liquefaction has a relatively low potential at depths greater than 50 feet and is
unlikely and/or will produce vertical strains well below 1 percent for depths below 60 feet
when relative densities are 40 to 60 percent and effective overburden pressures are two
or more atmospheres (i.e., 4,232 psf [Seed, 2005]).
The condition of liquefaction has two principal effects. One is the consolidation of loose
sediments with resultant settlement of the ground surface. The other effect is lateral
sliding. Significant permanent lateral movement generally occurs only when there is
significant differential loading, such as fill or natural ground slopes within susceptible
materials. No such loading conditions exist or are currently proposed at the site.
Liquefaction susceptibility is related to numerous factors and the following five conditions
should be concurrently present for liquefaction to occur: 1) sediments must be relatively
young in age and not have developed a large amount of cementation; 2) sediments must
generally consist of medium- to fine-grained, relatively cohesionless sands; 3) the
sediments must have low relative density; 4) free groundwater must be present in the
sediment; and 5) the site must experience a seismic event of a sufficient duration and
magnitude, to induce straining of soil particles. Only about one of these necessary five
concurrent conditions has the potential to affect the site. Therefore, the site is
characterized as having a very low potential for significant liquefaction, and resulting
deformation, to occur, provided the proposed project incorporates the recommendations
in this report into its design and construction.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 13
Seismic Densification
Seismic densification is a phenomenon that typically occurs in low relative density granular
soils (i.e., United States Soil Classification System [USCS] soil types SP, SW, SM, and SC)
that are above the groundwater table. These unsaturated granular soils are susceptible
if left in the original density (unmitigated), and are generally dry of the optimum moisture
content (as defined by the ASTM D 1557). During seismic-induced ground shaking, these
natural or artificial soils deform under loading and volumetrically strain, potentially resulting
in ground surface settlements.
Summary
It is the opinion of GSI that the susceptibility of the site to experience damaging
deformations from seismically-induced liquefaction is low owing to the dense/hard, nature
of the sediments that underlies the site and the depth of the regional groundwater table.
Although the near-surface soils are fine grained and are consistent with USCS soil types
SP, SW, SM, nor SC, the susceptibility of the subject site to experience seismic
densification is considered low, due to the dense/hard (cemented) nature of the underlying
sediments. Further, the recommendations for remedial earthwork and foundations would
further reduce any significant liquefaction/densification potential.
Other Geologic/Secondary Seismic Hazards
The following list includes other geologic/seismic related hazards that have been
considered during our evaluation of the site. The hazards listed are considered negligible
and/or mitigated as a result of site location, soil characteristics, freeboard, and typical site
development procedures:
•Subsidence
•Dynamic Settlement
It is important to keep in perspective that in the event of a major earthquake occurring on
any of the nearby major faults, strong ground shaking would occur in the subject site's
general area. Potential damage to any structure(s) would likely be greatest from the
vibrations and impelling force caused by the inertia of a structure's mass than from those
induced by the hazards considered above. Following implementation of remedial
earthwork and design of foundations described herein, this potential would be no greater
than that for other existing structures and improvements in the immediate vicinity that
comply with current and adopted building standards.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 14
LABORATORY TESTING
General
Laboratory tests were performed on representative bulk and relatively undisturbed
samples of the onsite earth materials collected during our subsurface exploration in order
to evaluate their physical characteristics. The test procedures used and results obtained
are presented below.
Classification
Soils were classified visually according to the Unified Soils Classification System
(Sowers and Sowers, 1979). The soil classifications are shown on the Boring Logs in
Appendix B.
Moisture-Density Relations
The field moisture content of bulk soil samples and the field moisture content, and dry
density of relatively undisturbed soil samples were evaluated in the laboratory, in general
accordance with ASTM D 2216 and ASTM D 2937. The results of these tests are shown
on the Boring Logs in Appendix B.
Laboratory Standard
The maximum density and optimum moisture content was evaluated for a representative,
near-surface bulk soil sample collected from the borings. Testing was performed in
general accordance with ASTM D 1557. The moisture-density relationships obtained for
this soil are shown on the following table:
SAMPLE LOCATION
AND DEPTH (FT)
MAXIMUM DENSITY
(PCF)
OPTIMUM MOISTURE
CONTENT (%)
B-1 @ 1-4 123.7 10.5
Expansion Potential
Expansion index testing was performed on a representative sample of near-surface soil
collected during the subsurface exploration, in general accordance with ASTM D 4829.
The results of expansion index testing are presented in the following table:
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 15
SAMPLE LOCATION AND DEPTH (FT)EXPANSION INDEX EXPANSION POTENTIAL*
B-2 @ 3-5 7 Very Low
B-2 @ 7-10 15 Very Low
* Classification per ASTM D 4829. Site soils may range from very low to potentially medium (E.I. = 0-90)
expansion potential.
Atterberg Limits
Tests were performed on a representative sample of the onsite earth materials collected
from the borings to evaluate their liquid limit, plastic limit, and plasticity index (P.I.) in
general accordance with ASTM D 4318. Test results are presented in the following table
and in Appendix D. Testing indicates that these samples of the onsite earth materials are
subject to plastic deformation.
SAMPLE LOCATION
AND DEPTH (FT)LIQUID LIMIT PLASTIC LIMIT PLASTICITY INDEX
B-2 @ 7-10 30 13 17
Direct Shear
Shear testing was performed on a representative, remolded sample of site soil in general
accordance with ASTM Test Method D 3080 in a Direct Shear Machine of the strain control
type. Prior to testing, the bulk soil sample was remolded to 90 percent of the laboratory
standard (ASTM D 1557). The shear test results are presented as follows and in
Appendix D:
SAMPLE LOCATION
AND DEPTH (FT)
PRIMARY RESIDUAL
COHESION
(PSF)
FRICTION ANGLE
(DEGREES)
COHESION
(PSF)
FRICTION ANGLE
(DEGREES)
B-1 @ 1-4 414 307 24.8 26.2
Saturated Resistivity, pH, and Soluble Sulfates, and Chlorides
GSI conducted testing on a representative sample of the near-surface earth materials
collected during the subsurface exploration for an evaluation of general soil corrosivity and
soluble sulfates, and chlorides. Test results are presented in Appendix D and the following
table:
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 16
SAMPLE LOCATION
AND DEPTH (FT)pH
SATURATED
RESISTIVITY
(ohm-cm)
SOLUBLE
SULFATES
(% by weight)
SOLUBLE
CHLORIDES
(ppm)
B-1 @ 1-4 7.2 930 0.0131 56
Corrosion Summary
Laboratory testing indicates that tested sample of the onsite soil is neutral with respect to
soil acidity/alkalinity; is severely corrosive to exposed, buried metals when saturated;
present negligible (“not applicable” per American Concrete Institute [ACI] 318-14) sulfate
exposure to concrete (i.e., Exposure Class S0 per Table 19.3.1.1 of ACI 318-14); and has
relatively low concentrations of soluble chlorides. It should be noted that GSI does not
consult in the field of corrosion engineering. Therefore, additional comments and
recommendations may be obtained from a qualified corrosion engineer based on the level
of corrosion protection required for the project, as determined by the project architect, civil
engineering, and/or structural engineer.
STORM WATER INFILTRATION RATE EVALUATION AND DISCUSSION
Subsurface Exploration
During GSI’s site-specific field studies, two (2) infiltration test borings (IB-1 and IB-2) were
advanced with a hollow stem auger drill rig to approximately 5 feet below ground surface.
The purpose of the borings was to evaluate the site’s near-surface soil and geologic
conditions, with respect to storm water infiltration. The test borings were logged by a GSI
representative, and are presented in Appendix B. The approximate location of the borings
are presented on the attached Geotechnical Map (Plate 1).
USDA Study
A review of the United States Department of Agriculture database (USDA; 1973, 2017)
indicates surficial soils at the site were evaluated with infiltration rates ranging from 0.00
to 0.06 inches per hour (Huerhuero loam [HrC], Hydrologic Soil Group {HSG} D). Our site
specific infiltration test, obtained infiltration rates similar (0.031 to 0.064 inches per hour)
to the USDA report. Based on the geologic units observed and/or encountered during the
current subsurface investigation, the soils encountered onsite typically become denser,
and less permeable with depth. As such, the resultant infiltration rates for these materials
would be expected to be similar to the lower rate reported by the USDA.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 17
Infiltration Feasibility
In general accordance with the City of Chula Vista Design Manual: BMP Design Manual
(City, 2015), the infiltration feasibility for this site was evaluated. An evaluation of the soils
sathydraulic conductivity, or (K ) was performed for this study, in accordance with the
Porchet, or inverse auger hole method (Van Hoorm, 1979; USBR, 1984), for the various soil
types encountered onsite in the vicinity of planned BMPs. Testing was performed at, or
near the planned infiltration surface elevation for each basin. Based on the testing
performed, infiltration rates ranging from 0.031 to 0.064 inches per hour were evaluated,
and are summarized in the following table. Test data sheets are presented in Appendix E.
Infiltration test boring locations are shown on Plate 1.
INFILTRATION
TEST HOLE INFILTRATION MEDIUM INFILTRATION RATE
(INCHES PER HOUR)SOIL UNIT PER USDA (1973)
IB-1 Silty Sand/Clayey Sand/Sandy
Clay 0.064 Huerhuero loam
IB-2 Silty Sand/Clayey Sand/Sandy
Clay 0.031 Huerhuero loam
Average Rate = 0.0475
AA suitability assessment safety factor (or factor of safety [FOS]) S equal to 1.5 was
evaluated in accordance with Worksheet Form D.5-1(City, 2015), and is also included
herein (see Appendix F). An additional discussion of infiltration feasibility is presented in
Appendix F (Worksheet C.4.1, provided by the City [2015]).
The average calculated infiltration rate is ±0.047 inches/hr. Using a minimum FOS of 2.0,
the “reliable infiltration rate” is ±0.02 inches/hr. This is much less than the lower limit of
infiltration recommended by the USEPA (0.52 inches/hr [see Clar, et al., 2004]), and less
than that currently allowed by the City of San Diego (0.05 inches/hr. [see City of San Diego,
2017]), for partial infiltration. Existing or proposed fill, and/or moisture sensitive
improvements, such as pavements, and utility trench backfill, would likely be adversely
affected, including offsite improvements, causing settlement and distress. Bio-basins can
adversely affect the performance of the onsite and offsite structures foundation systems
by: 1) Increasing soil moisture transmission rates through concrete flooring; and
2) Increase the potential for a loss in bearing strength of soil, due to saturation. Onsite
mitigative grading of compressible near-surface soils for the support of structures generally
involves removal and recompaction. This is anticipated to create a permeability contrast,
and the potential for the development of a shallow “perched” and mounded water table,
which can reasonably be anticipated to migrate laterally, beneath the structure(s), or offsite
onto adjacent property, causing settlement and associated distress. Accordingly,
infiltrating into site soils is poor engineering judgement. Thus, no infiltration is
recommended.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 18
Based on our review and engineering analysis, we consider the site belonging to HSG D
and recommend a “no infiltration” BMP design, owing to the potential for mounding and
associated settlement and distress, onsite and offsite. Furthermore, any basin constructed
entirely of compacted fill is considered as belonging to HSG D, and a “no infiltration” BMP
design is warranted ([EPA], Clar, et al., 2004). A “no infiltration” design is also
recommended where building foundations or settlement-sensitive improvements are
located within 10 feet of a given basin.
Onsite Filtration/Infiltration-Runoff Retention Systems
General design criteria regarding the use of onsite filtration-infiltration-runoff retention
systems (OIRRS) are presented below.
Should onsite infiltration-runoff retention systems (OIRRS) be required for Best
Management Practices (BMPs) or Low Impact Development (LID) principles for the project,
some guidelines should/must be followed in the planning, design, and construction of such
systems. Such facilities, if improperly designed or implemented without consideration of
the geotechnical aspects of site conditions, can contribute to flooding, saturation of
bearing materials beneath site improvements, slope instability, and possible concentration
and contribution of pollutants into the groundwater or storm drain and/or utility trench
systems.
Some of the methods which are utilized for onsite infiltration include percolation basins,
dry wells, bio-swale/bio-retention, permeable pavers/pavement, infiltration trenches, filter
boxes and subsurface infiltration galleries/chambers. Some of these systems are
constructed using native and import soils, perforated piping, and filter fabrics while others
employ structural components such as storm water infiltration chambers and
filters/separators. Every site will have characteristics which should lend themselves to one
or more of these methods, but not every site is suitable for OIRRS. In practice, OIRRS are
usually initially designed by the project design civil engineer. Selection of methods should
include (but should not be limited to) review by licensed professionals including the
geotechnical engineer, hydrogeologist, engineering geologist, project civil engineer,
landscape architect, environmental professional, and industrial hygienist. Applicable
governing agency requirements should be reviewed and included in design
considerations.
Based on our evaluation, the following issues should be addressed when considering any
storm water BMP design:
1.The probability of limited space and proximity of settlement-sensitive improvements
to potential treatment area BMPs.
2.The presence of a thin layer of engineered fill overlying dense bedrock (as-built
condition) and the potential for developing a shallow, perched water table beneath
foundations.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 19
3.Potential for adverse performance of planned improvements such as floor slabs,
below grade walls, and foundations, due to potential settlement from saturation, or
other distress due to water vapor transmission.
4.The potential for the migration of subsurface water offsite, beneath adjacent
residential properties, or streets, and/or into utility line trenches.
The following geotechnical guidelines should be considered when designing onsite
infiltration-runoff retention systems:
•The onsite soils fall into Hydrologic Soil Group (HSG) “D.”
•It is not good engineering practice to allow water to saturate soils, especially near
slopes or improvements; however, the controlling agency/authority may now
require this.
•Areas adjacent to, or within, the OIRRS that are subject to inundation should be
properly protected against scouring, undermining, and erosion, in accordance with
the recommendations of the design engineer.
•Should they be required, where infiltration systems are located near slopes or
improvements, impermeable liners and subdrains should be used along the bottom
of bioretention swales/basins located within the influence of such slopes and
structures. Impermeable liners used in conjunction with bioretention basins should
consist of a 30-mil polyvinyl chloride (PVC) membrane that is covered by a
minimum of 12 inches of clean soil, free from rocks and debris, with a maximum
4:1 (h:v) slope inclination, or flatter, and meets the following minimum
specifications:
Specific Gravity (ASTM D792): 1.2 (g/cc, min.); Tensile (ASTM D882):
73 (lb/in-width, min); Elongation at Break (ASTM D882): 380 (%, min);
Modulus (ASTM D882): 32 (lb/in-width, min.); and Tear Strength
(ASTM D1004): 8 (lb/in, min); Seam Shear Strength (ASTM D882) 58.4 (lb/in,
min); Seam Peel Strength (ASTM D882) 15 (lb/in, min).
•Subdrains for basins should consist of at least 4-inch diameter Schedule 40 or SDR
35 drain pipe with perforations oriented down. The drain pipe should be sleeved
with a filter sock.
•Utility backfill within OIRRS should consist of a two-sack mix of slurry.
Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.),
should be reviewed by this office prior to construction, so that construction is in
accordance with the conclusions and recommendations of this report. Based on our
review, supplemental recommendations and/or further geotechnical studies may be
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 20
warranted. It should be noted that structural and landscape plans were not available for
review at this time.
PRELIMINARY CONCLUSIONS
Based on our field exploration, laboratory testing, and geotechnical engineering analysis,
it is our opinion that the site appears suitable for the proposed development from a
geotechnical engineering and geologic viewpoint, provided that the recommendations
presented in the following sections are properly incorporated into the design and
construction phases of site development. The primary geotechnical concerns with respect
to the currently proposed development are:
•Settlement potential.
•Earth materials characteristics and depth to competent bearing material.
•On-going expansion potential of the onsite soils.
•On-going corrosion potential of the onsite earth materials.
•Potential for perched groundwater to occur during and after development.
•Non-structural zone on un-mitigated perimeter conditions (improvements subject
to distress) or on existing fill/backfill (if not removed and recompacted).
•Temporary slope stability during remedial grading and the installation of utilities and
foundations.
•Regional seismic activity and the associated seismic response of the proposed
building foundation.
The recommendations presented herein consider these as well as other aspects of the site.
The engineering analyses, performed, concerning site preparation and the
recommendations presented herein have been completed using the information provided
and obtained during our field work. In the event that any significant changes are made to
proposed site development, the conclusions and recommendations contained in this
report shall not be considered valid unless the changes are reviewed and the
recommendations of this report are evaluated or modified in writing by this office.
Foundation design parameters are considered preliminary until the foundation design,
layout, and structural loads are provided to this office for review.
1.Soil engineering, observation, and testing services should be provided during
grading to aid the contractor in removing unsuitable soils and in his effort to
compact the fill.
2.Geologic observations should be performed during any grading and foundation
construction to verify and/or further evaluate geologic conditions. Although unlikely,
if adverse geologic structures are encountered, supplemental recommendations
and earthwork may be warranted.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 21
3.Existing fill are considered unsuitable for the support of the planned settlement-
sensitive improvements (i.e., foundations, new slab-on-grade floors, walls, exterior
hardscape, etc.) and new planned fills. Unsuitable soils within the influence of
planned settlement-sensitive improvements and planned fill should be removed to
expose unweathered old paralic deposits and then be reused as properly
engineered fill. Based on the available subsurface data, remedial grading
excavations are anticipated to extend to depths of approximately 3 to 5 feet below
existing grades. However, locally deeper remedial grading excavations cannot be
precluded and should be anticipated.
4.Expansion Index (E.I.) testing performed on a representative sample of the onsite
soils indicates very low, to potentially low expansive conditions (E.I.=0-50). In
addition, Atterberg limits testing on another representative sample of the onsite soils
indicates low-plastic soil conditions. On a preliminary basis, the onsite soils are
considered non-detrimentally expansive. However, the possibility of encountering
detrimentally expansive soils cannot be precluded (E.I. =21-90), thus expansive soil
foundation design recommendations have been provided herein, in addition to
conventional foundation design .
5.Laboratory testing indicates that tested sample of the onsite soil is neutral with
respect to soil acidity/alkalinity; is severely corrosive to exposed, buried metals
when saturated; present negligible (“not applicable” per American Concrete
Institute [ACI] 318-14) sulfate exposure to concrete (i.e., Exposure Class S0 per
Table 19.3.2.1 of ACI 318-14); and has relatively low concentrations of soluble
chlorides. It should be noted that GSI does not consult in the field of corrosion
engineering. Therefore, additional comments and recommendations may be
obtained from a qualified corrosion engineer based on the level of corrosion
protection required for the project, as determined by the project architect, civil
engineering, and/or structural engineer.
6.Site soils are considered erosive. Surface drainage should be designed to eliminate
the potential for concentrated flows. Positive surface drainage away from
foundations is recommended. Temporary erosion control measures should be
implemented until vegetative covering is well established. The owners will need to
maintain proper surface drainage over the life of the project.
7.Regional groundwater was not encountered to the depths explored in this
investigation, and is not anticipated to significantly affect the planned
improvements. However, due to the nature of site earth materials, there is a
potential for perched water to occur both during and following site development.
This potential should be disclosed to all interested/affected parties. Should perched
water conditions be encountered, this office could provide recommendations for
mitigation. Typical mitigation includes subdrainage system, cut-off barriers, etc.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 22
8.The removal and recompaction of potentially compressible soils below a 1:1 (h:v)
projection down from the bottom outside of planned settlement-sensitive
improvements and fill along the perimeter of the site will be limited due to boundary
restrictions. As such, any settlement-sensitive improvement located above a
1:1 (h:v) projection from the bottom outboard edge of the remedial grading
excavation at the property line would require deepened foundations below this
plane, additional reinforcement, or would retain some potential for distress and
therefore, a reduced serviceable life. On a preliminary basis, any planned
settlement-sensitive improvements located within approximately 3 feet from the
property lines would require deepened foundations or additional reinforcement by
means of ground improvement or specific structural design. Otherwise, these
improvements would retain a potential to exhibit distress. This should be
considered during project design.
9.In order to provide uniform foundation support, all footings for the structures should
be underlain by at least 24 inches of engineered fill beneath the foundations.
10.On a preliminary basis, temporary slopes should be constructed in accordance with
CAL-OSHA guidelines for Type “D” soils, provided water or seepage is not present.
All temporary slopes should be evaluated by the geotechnical consultant, prior to
worker entry. Should adverse conditions be identified, the slope may need to be
laid back to a flatter gradient or require the use of shoring. If the recommended
temporary slopes conflict with property lines or existing improvements that need to
remain in serviceable use, alternating slot excavations or shoring may be necessary.
11.The site is subject to moderate to strong ground shaking should an earthquake
occur along any of a number of the regional fault systems. The seismic acceleration
values and design parameters provided herein should be considered during the
design of the proposed development. The adverse effects of seismic shaking on
the structure(s) will likely be wall cracks, some foundation/slab distress, and some
seismic settlement. However, it is anticipated that the proposed structures will be
repairable in the event of the design seismic event. This potential should be
disclosed to any owners and all interested/affected parties.
12.The feasibility of successful storm water infiltration at the subject site is considered
very low (“no infiltration”), owing to the dense and cemented nature of the bedrock
that occurs in the near surface (Hydrologic Soil Group [HSG] D). If storm water
were to infiltrate, it would most likely perch upon the bedrock, mound, and migrate
laterally. This would likely have detrimental effects on onsite and offsite
improvements, including settlement of utility trench backfill and associated
improvements.
13.General Earthwork and Grading Guidelines are provided at the end of this report as
Appendix G. Specific recommendations are provided below.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 23
EARTHWORK CONSTRUCTION RECOMMENDATIONS
Removal and Recompaction of Potentially Compressible Earth Materials
Potentially compressible undocumented fill and any weathered old paralic deposits should
be removed to expose suitable unweathered old paralic deposits. Following removal,
these soils should be cleaned of any vegetation and deleterious debris, moisture
conditioned to at least optimum moisture, and then be recompacted to at least 90 percent
of the laboratory standard (ASTM D 1557). Based on the available data, excavations
necessary to remove unsuitable soils are anticipated to range between approximately 3 to
5¾ feet BEGS. The potential to encounter thicker sections of unsuitable soils that require
deeper remedial grading excavations than stated above cannot be precluded and should
be anticipated. Potentially compressible soils should be removed below a 1:1 (h:v)
projection down from the bottom, outboard edge of any settlement-sensitive improvement
or limits of planned fill. Remedial grading excavations should be observed by the
geotechnical consultant prior to scarification and fill placement. Once observed and
approved, the bottom of the remedial grading excavation should be scarified at least 6 to
8 inches, moisture conditioned to at least the soil’s optimum moisture content, and then
recompacted to a minimum 90 percent of the laboratory standard (ASTM D 1557).
Owing to the age of the existing development at the site, it is possible that underground
structures (i.e., cisterns, seepage pits, etc.) may be encountered during remedial grading.
This office should be informed if any underground structures are encountered during
remedial earthwork. Based on exposed conditions, this office would provide
recommendations for mitigation.
Perimeter Conditions
It should be noted that the 2016 CBC (CBSC, 2016) indicates that the removal of
unsuitable soils be performed across all areas to be graded, under the purview of the
grading permit, not just within the influence of the residential structures. Relatively deep
removals may also necessitate a special zone of consideration, on perimeter/confining
areas. This zone would be approximately equal to the depth of removals, if removals
cannot be performed onsite or offsite. In general, any planned improvement located above
a 1:1 (h:v) projection up from the bottom, outboard edge of the remedial grading
excavation at the subdivision boundary would be affected by perimeter conditions. On a
preliminary basis, any planned settlement-sensitive improvements located within a few feet
(3 to 5¾ feet) of the subdivision boundary would require deepened foundations or
additional reinforcement by means of ground improvement or specific structural design,
for perimeter conditions discussed above. Otherwise these improvements may be subject
to distress and a reduced serviceable lifespan. This will also require proper disclosure to
any owners and all interested/affected parties should this condition exist at the conclusion
of grading. The need for remedial measures for support of settlement-sensitive
improvements near the subdivision boundary should be further evaluated at the 40-scale
grading plan review stage.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 24
Fill Placement
Following scarification of the bottom of the remedial grading excavation, the reused onsite
soils and import (if necessary) should be placed in ±6- to ±8-inch lifts, cleaned of
vegetation and debris, moisture conditioned, and compacted to achieve a minimum
relative compaction of 90 percent of the laboratory standard (ASTM D 1557). In general,
moisture conditioning should be such that clayey site soils (i.e., existing fill and old paralic
deposits) are placed to at least 1.2 times the soils optimum moisture content, within 2 feet
of finish grade.
Overexcavation
In order to provide uniform foundation and slab-on-grade floor support, mitigate water
vapor transmission potential, and to facilitate improvements construction, it is
recommended that building pads (cut pads and transition pads) are overexcavated
(undercut) to a depth of at least 3 feet below pad grade or 2 feet below the lowest bottom
of the footing elevation (whichever is greater). When removals do not provide for the
minimum fill thickness with a given building pad, the building pad shall be overexcavated
as described herein.
Overexcavation should be completed across the entire building pad in case the location
of the building footprint requires modification after grading. The maximum:minimum fill
thickness (slope) across a lot should not exceed 3:1 (maximum:minimum) and
overexcavation is recommended when necessary. The bottom of the overexcavation
should be graded such that it slopes away from the residential structure/lot, preferably
toward a street. Prior to fill placement, the bottom of the overexcavation should be
scarified at least 6 to 8 inches, moisture conditioned to at least the soil’s optimum moisture
content, and then recompacted to a minimum 90 percent of the laboratory standard (ASTM
D 1557).
Temporary Slopes
On a preliminary basis, temporary slopes up to 20 feet in overall height should conform to
CAL-OSHA and/or OSHA requirements for Type “B” soils. Temporary slopes, up to a
maximum gross height of ±20 feet, may be excavated at a 1:1 (h:v) gradient, or flatter,
provided seepage is not present. Construction materials or soil stockpiles should not be
placed within ‘H’ of any temporary slope where ‘H’ equals the height of the temporary
slope, and this assumes no groundwater is present. All temporary slopes should be
observed by a licensed engineering geologist and/or geotechnical engineer prior to worker
entry into the excavation. Based on the exposed field conditions, inclining temporary
slopes to flatter gradients or the use of shoring may be necessary if adverse conditions are
observed. Shoring appears necessary for vertical excavations and where property lines
or existing improvements (to remain in service during and after construction) are in conflict
with the recommended gradient of temporary slopes.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 25
OTHER EARTHWORK CRITERIA
Expansive Soil Mitigation/Selective Grading Considerations
Site soils are generally very low expansive, and conventional foundations systems are
anticipated; however, some expansive soils exist onsite, which may locally govern
foundation design. As an alternative to designing and constructing specialized foundation
and slab-on-grade floor systems to resist expansive soil effects, selective grading
techniques may be considered to potentially create a non-detrimentally expansive soil cap,
or to reduce the magnitude of the expansion potential of such soils. Selective grading
techniques may include the removal and replacement of expansive soils within the upper
7 feet of finish grade, and 7 feet outside the building footprint, with very low expansive soils
(E.I. <20) with a relatively low plasticity (P.I. less than 15). Alternatively, very low expansive
and non- or slightly plastic native and/or import soils may be blended with the onsite
expansive soils within the upper 7 feet of pad grade. If the latter is selected, GSI
recommends a blend ratio (by volume) of at least 4:1 (very low expansive and non- or
slightly plastic native and/or import soils to onsite expansive soils) on a preliminary basis.
The blend ratio should be re-evaluated during grading based on selective sampling and
testing.
Import Soils
If import fill is necessary, a sample of the soil import should be evaluated by this office prior
to importing, in order to assure compatibility with the onsite soils and the
recommendations presented in this report. If non-manufactured materials are used,
environmental documentation for the export site should be provided for GSI review. At
least three business days of lead time should be allowed by builders or contractors for
proposed import submittals. This lead time will allow for environmental document review,
particle size analysis, laboratory standard, expansion testing, and blended import/native
characteristics as deemed necessary. Import soils should be non-detrimentally expansive
(i.e., E.I. less than 21 and P.I. less than 15). The use of subdrains at the bottom of the fill
cap may be necessary, and may be subsequently recommended based on compatibility
with onsite soils.
Graded Slope Construction
At this time graded slope construction is not anticipated for this project; however, if
considered follow the guidelines provided herein.
Graded fill slopes should be constructed at gradients no steeper than 2:1 (h:v). Fill slopes
should be properly keyed and benched if constructed along surfaces steeper than 5:1
(h:v). All fill slopes should be compacted to at least 90 percent of the laboratory standard
(ASTM D 1557) throughout, including the slope face.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 26
Graded cut slopes should be constructed at gradients no steeper than 1.5:1 (h:v) without
further evaluation. All cut slopes should be mapped by a geologist during construction.
Although not anticipated at this time, should undocumented fill, colluvium, or highly
weathered old paralic deposits be exposed in cut slopes, remedial grading including
stabilization fills or inclining the cut slope to a gradient flatter than the adverse structure
may be necessary. The type of remedial grading would be based on the conditions
exposed during cut slope construction.
Stabilization Fills/Slope Drainage
Stabilization fills are not anticipated at this time, but cannot be entirely precluded. The
need for stabilizations fills will be evaluated during grading the 40-scale grading plan
review stage and grading.
Excavation Observation and Monitoring (All Excavations)
When excavations are made adjacent to an existing improvement (i.e., utility, road or
building) there is a risk of some damage even if a well designed system of excavation is
planned and executed. We recommend, therefore, that a systematic program of
observations be made before, during, and after construction to determine the effects (if
any) of construction on existing improvements.
We believe that this is necessary for two reasons: First, if excessive movements (i.e., more
than ½ inch) are detected early enough, remedial measures can be taken which could
possibly prevent serious damage to existing improvements. Second, the responsibility for
damage to the existing improvement can be determined more equitably if the cause and
extent of the damage can be determined more precisely.
Monitoring should include the measurement of any horizontal and vertical movements of
the existing structures/improvements. Locations and type of the monitoring devices should
be selected prior to the start of construction. The program of monitoring should be agreed
upon between the project team, the site surveyor and the Geotechnical
Engineer-of-Record, prior to excavation.
Reference points on existing walls, buildings, and other settlement-sensitive improvements.
These points should be placed as low as possible on the wall and building adjacent to the
excavation. Exact locations may be dictated by critical points, such as bearing walls or
columns for buildings; and surface points on roadways or curbs near the top of the
excavation.
For a survey monitoring system, an accuracy of a least 0.01 foot should be required.
Reference points should be installed and read initially prior to excavation. The readings
should continue until all construction below ground has been completed and the
permanent backfill has been brought to final grade.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 27
The frequency of readings will depend upon the results of previous readings and the rate
of construction. Weekly readings could be assumed throughout the duration of
construction with daily readings during rapid excavation near the bottom of the excavation.
The reading should be plotted by the Surveyor and then reviewed by the Geotechnical
Engineer. In addition to the monitoring system, it would be prudent for the Geotechnical
Engineer and the Contractor to make a complete inspection of the existing structures both
before and after construction. The inspection should be directed toward detecting any
signs of damage, particularly those caused by settlement. Notes should be made and
pictures should be taken where necessary.
Observation
It is recommended that all excavations be observed by the Geologist and/or Geotechnical
Engineer. Any fill which is placed should be approved, tested, and verified if used for
engineered purposes. Should the observation reveal any unforseen hazard, the Geologist
or Geotechnical Engineer will recommend treatment. Please inform GSI at least 24 hours
prior to any required site observation.
Earthwork Balance (Shrinkage/Bulking)
The volume change of excavated materials upon compaction as engineered fill is
anticipated to vary with material type and location. Based on the available data, the overall
earthwork shrinkage and bulking may be approximated by using the following parameters:
Existing Artificial Fill ...............................5% to 10% shrinkage
Bedrock
75% Earth/25% Rock (weathered bedrock)..............8% shrinkage
50% Earth/50% Rock................................5% shrinkage
25% Earth/75% Rock (unweathered bedrock).............12% bulking
It should be noted that the above factors are estimates only, based on preliminary data.
Existing fill and colluvium may achieve higher shrinkage if organics or clay content is
higher than anticipated, or if compaction averages more than 92 percent of the laboratory
standard (ASTM D 1557). Final earthwork balance factors could vary. In this regard, it is
recommended that balance areas be reserved where grades could be adjusted up or
down near the completion of grading in order to accommodate any yardage imbalance for
the project.
PRELIMINARY RECOMMENDATIONS - FOUNDATIONS
General
Preliminary recommendations for foundation design and construction are provided in the
following sections. These preliminary recommendations have been developed from our
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 28
understanding of the currently planned site development, site observations, subsurface
exploration, laboratory testing, and engineering analyses. Foundation design should be
re-evaluated at the conclusion of site grading/remedial earthwork for the as-graded soil
conditions. Although not anticipated, revisions to these recommendations may be
necessary. In the event that the information concerning the proposed development plan
is not correct, or any changes in the design, location or loading conditions of the proposed
residential structures are made, the conclusions and recommendations contained in this
report shall not be considered valid unless the changes are reviewed and conclusions of
this report are modified or approved in writing by this office.
The information and recommendations presented in this section are not meant to
supercede design by the project structural engineer or civil engineer specializing in
structural design. Upon request, GSI could provide additional input/consultation regarding
soil parameters, as related to foundation design.
In the following sections, GSI provides preliminary design and construction
recommendations for foundations underlain by both non-detrimentally and detrimentally
expansive soil conditions. Foundation systems constructed within the influence of
detrimentally expansive soils (i.e., E.I. > 20 and P.I. > 15) will require specific design to
resist expansive soil effects per Sections 1808.6.1 or 1808.6.2 of the 2016 CBC.
Preliminary Foundation Design
1.The foundation systems should be designed and constructed in accordance with
guidelines presented in the 2016 CBC.
2.An allowable bearing value of 2,000 pounds per square foot (psf) may be used for
the design of footings that maintain a minimum width of 12 inches and a minimum
depth of 12 inches (below the lowest adjacent grade), and are founded entirely into
approved engineered fill. This value may be increased by 20 percent for each
additional 12 inches in footing depth to a maximum value of 2,500 psf for footings
founded into approved engineered fill. This value may be increased by one-third
when considering short duration seismic or wind loads. Isolated pad footings
should have a minimum dimension of at least 24 inches square and a minimum
embedment of 24 inches below the lowest adjacent grade into approved
engineered fill. Foundation embedment depth excludes concrete slabs-on-grade,
and/or slab underlayment.
3.For foundations deriving passive resistance from approved engineered fill, a passive
earth pressure may be computed as an equivalent fluid having a density of 250 pcf,
with a maximum earth pressure of 2,500 psf.
4.The upper 6 inches of passive pressure should be neglected if not confined by
slabs or pavement.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 29
5.For lateral sliding resistance, a 0.35 coefficient of friction may be utilized for a
concrete to soil contact when multiplied by the dead load.
6.When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third.
7.All footing setbacks from slopes should comply with Figure 1808.7.1 of the
2016 CBC. GSI recommends a minimum horizontal setback distance of 7 feet as
measured from the bottom, outboard edge of the footing to the slope face.
8.Footings for structures adjacent to retaining walls should be deepened so as to
extend below a 1:1 projection up from the heel of the retaining wall. Alternatively,
the retaining wall may be designed for the applicable surcharge.
PRELIMINARY FOUNDATION CONSTRUCTION RECOMMENDATIONS
Conventional Foundation and Slab-On-Grade Floor Systems
The following recommendations are intended to support foundations and slab-on-grade
floor systems underlain by at least 7 feet of non-expansive soils (i.e., E.I.<21 and P.I. <15).
It is possible that earthwork mitigation of expansive soils may be required for the use
conventional foundation and slab-on-grade floor systems in localized areas.
1.Exterior and interior footings should be founded into approved engineered fill at a
minimum depth of 12 or 18 inches below the lowest adjacent grade for one- or
two-story floor loads, respectively. For one- and two-story floor loads, footing
widths should be 12 and 15 inches, respectively. Isolated, exterior column and
panel pads, or wall footings, should be at least 24 inches square, and founded at
a minimum depth of 24 inches into approved engineered fill. All footings should be
minimally reinforced with four No. 4 reinforcing bars, two placed near the top and
two placed near the bottom of the footing.
2.All interior and exterior column footings, and perimeter wall footings, should be tied
together via grade beams in at least two directions. The grade beam should be at
least 12 inches square in cross section, and should be provided with a minimum of
one No.4 reinforcing bar at the top, and one No.4 reinforcing bar at the bottom of
the grade beam. The base of the reinforced grade beam should be at the same
elevation as the adjoining footings.
3.A minimum concrete slab-on-grade thickness of 5 inches is recommended.
4.Concrete slabs should be reinforced with a minimum of No. 3 reinforcement bars
placed at 18 inches on center, in two horizontally perpendicular directions (i.e., long
axis and short axis).
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 30
5.All slab reinforcement should be supported to ensure proper mid-slab height
positioning during placement of the concrete. "Hooking" of reinforcement is not an
acceptable method of positioning.
6.Slab subgrade pre-soaking is not required for non-detrimentally expansive soil
conditions. However, the client should consider pre-wetting the slab subgrade
materials to at least the soil’s optimum moisture content to a minimum depth of
12 inches, prior to the placement of the underlayment sand and vapor retarder.
7.Soils generated from footing excavations to be used onsite should be compacted
to a minimum relative compaction of 90 percent of the laboratory standard
(ASTM D 1557), whether the soils are to be placed inside the foundation perimeter
or in the yard/right-of-way areas. This material must not alter positive drainage
patterns that direct drainage away from the structural areas and toward the street.
8.Reinforced concrete mix design should conform to “Exposure Class C1” in
Table 19.3.2.1 of ACI 318-14 since concrete would likely be exposed to moisture.
Post-Tensioned Foundations
Post-tension (PT) foundations should be used to mitigate the damaging effects of
expansive soils on the planned residential foundations and slab-on-grade floors if
expansive soil conditions are encountered within 7 feet of finish grade. They may also be
used for increased performance of foundations constructed on non-detrimentally
expansive soils.
Current laboratory testing indicates that the onsite soils exhibit expansion index (E.I.)
values ranging up to E.I. = 15 and some soils with a plasticity index (P.I.) of 17. As such,
some soils meet the criteria of detrimentally expansive soils as defined in Section 1803.5.2
of the 2016 CBC. Furthermore, the possibility of encountering medium expansive soils
(E.I. = 51-90) during grading cannot be precluded. Thus, GSI is providing geotechnical
parameters for the design of PT foundations within the influence of such soil conditions.
The post-tension foundation designer may elect to exceed these minimal
recommendations to increase slab stiffness performance. Post-tension design may be
either ribbed or mat-type. The latter is also referred to as uniform thickness foundation
(UTF). The use of a UTF is an alternative to the traditional ribbed-type. The UTF offers a
reduction in grade beams (i.e., that method typically uses a single perimeter grade beam
and possible “shovel” footings), but has a thicker slab than the ribbed-type.
The information and recommendations presented in this section are not meant to
supercede design by a registered structural engineer or civil engineer qualified to perform
post-tensioned design. Post-tension foundations should be designed using sound
engineering practice and be in accordance with local and 2016 CBC requirements. Upon
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 31
request, GSI can provide additional data/consultation regarding soil parameters as related
to post-tensioned foundation design.
From a soil expansion/shrinkage standpoint, a common contributing factor to distress of
structures using post-tensioned slabs is a "dishing" or "arching" of the slabs. This is caused
by the fluctuation of moisture content in the soils below the perimeter of the slab primarily
due to onsite and offsite irrigation practices, climatic and seasonal changes, and the
presence of expansive soils. When the soil environment surrounding the exterior of the
slab has a higher moisture content than the area beneath the slab, moisture tends to
migrate inward, underneath the slab edges to a distance beyond the slab edges referred
to as the moisture variation distance. When this migration of water occurs, the volume of
the soils beneath the slab edges expand and cause the slab edges to lift in response. This
is referred to as an edge-lift condition. Conversely, when the outside soil environment is
drier, the moisture transfer regime is reversed and the soils underneath the slab edges lose
their moisture and shrink. This process leads to dropping of the slab at the edges, which
leads to what is commonly referred to as the center lift condition. A well-designed, post-
tension slab having sufficient stiffness and rigidity provides a resistance to excessive
bending that results from non-uniform swelling and shrinking slab subgrade soils,
particularly within the moisture variation distance, near the slab edges. Other mitigation
techniques typically used in conjunction with post-tensioned slabs consist of a
combination of specific soil pre-saturation and the construction of a perimeter "cut-off" wall
grade beam. Soil pre-saturation consists of moisture conditioning the slab subgrade soils
prior to the post-tension slab construction. This effectively reduces soil moisture migration
from the area located outside the building toward the soils underlying the post-tension
slab. Perimeter cut-off walls are thickened edges of the concrete slab that impedes both
outward and inward soil moisture migration.
Slab Subgrade Pre-Soaking
Pre-moistening of the slab subgrade soil is recommended for these soil conditions. The
moisture content of the subgrade soils should be equal to or greater than optimum
moisture to a depth equivalent to the exterior footing depth in the slab areas (typically 12,
and 18 inches for very low to low, and medium expansive soils, respectively).
Pre-moistening and/or pre-soaking should be evaluated by the soils engineer 72 hours
prior to vapor retarder placement. In summary:
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 32
EXPANSION
INDEX
PAD SOIL MOISTURE CONSTRUCTION
METHOD
SOIL MOISTURE
RETENTION
Very Low (0-20)Upper 12 inches of pad at
or above soil optimum
moisture
Wetting and/or
reprocessing
Periodically wet or cover
with plastic after trenching.
Evaluation 72 hours prior to
placement of concrete.
Lo w (21-50)U p per 12 inches of pa d soil
moisture 2 percent over
optimum
Wetting and/or
reprocessing
Periodically wet or cover
with plastic after trenching.
Evaluation 72 hours prior to
placement of concrete.
M edium (51-90)U p per 18 inches of pa d soil
moisture 2 percent over
optimum or 1.2 times
o ptim um , w hichever is
greater.
Berm and flood or wetting
and reprocessing
Periodically wet or cover
with plastic after trenching.
Evaluation 72 hours prior to
placement of concrete.
Perimeter Cut-Off Walls
Perimeter cut-off walls should be 12 and 18 inches deep for very low to low, and medium
expansive soil conditions, respectively. The cut-off walls may be integrated into the slab
design or independent of the slab. The cut-off walls should be a minimum of 6 inches
thick. The bottom of the perimeter cut-off wall should be designed to resist tension, using
cable or reinforcement per the structural engineer.
Post-Tensioned Foundation Design
The following recommendations for design of post-tensioned slabs have been prepared
in general compliance with the requirements of the recent Post Tensioning Institute’s
(PTI’s) publication titled “Design of Post-Tensioned Slabs on Ground, Third Edition”
(PTI, 2004), together with it’s subsequent addendums (PTI, 2008).
Soil Support Parameters
The recommendations for soil support parameters have been provided based on the
typical soil index properties for soils that are very low to medium in expansion potential.
The soil index properties are typically the upper bound values based on our experience
and practice in the southern California area. The following table presents suggested
minimum coefficients to be used in the Post-Tensioning Institute design method.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 33
Thornthwaite Moisture Index -20 inches/year
Correction Factor for Irrigation 20 inches/year
Depth to Constant Soil Suction 7 feet
Constant soil Suction (pf)3.6
Moisture Velocity 0.7 inches/month
Plasticity Index (P.I.)<15-50
Based on the above, the recommended soil support parameters are tabulated below:
DESIGN PARAMETERS
EXPANSION POTENTIAL
VERY LOW TO LOW
(E.I. = 0-50)
MEDIUM
(E.I. = 51-90)
me center lift 9.0 feet 8.7 feet
me edge lift 5.2 feet 4.5 feet
my center lift 0.3 inches 0.49 inches
my edge lift 0.7 inch 1.3 inch
Bearing Value 1,000 psf 1,000 psf(1)
Lateral Pressure 250 psf 175 psf
Subgrade Modulus (k)100 pci/inch 85 pci/inch
Minimum Perimeter
Footing Embedment (2)12 inches 18 inches
Internal bearing values within the perimeter of the post-tension slab may be increased to 1,500 psf for a minimum(1)
embedment of 12 inches, then by 20 percent for each additional foot of embedment to a maximum of 2,000 psf.
As measured below the lowest adjacent compacted subgrade surface without landscape layer or sand underlayment(2)
(interior footings also).
Note: The use of open bottomed or raised planters adjacent to foundations will require more onerous design
parameters.
Deepened footings/edges around the slab perimeter must be used to minimize
non-uniform surface moisture migration (from an outside source) beneath the slab. An
edge depth of 12 inches should be considered a minimum. The bottom of the deepened
footing/edge should be designed to resist tension, using cable or reinforcement per the
structural engineer.
The parameters are considered minimums and may not be adequate to represent all
expansive soils/drainage conditions such as adverse drainage and/or improper
landscaping and maintenance. The above parameters are applicable provided the
structure has positive drainage that is maintained away from the structure. In addition, no
trees with significant root systems are to be planted within 15 feet of the perimeter of
foundations. Therefore, it is important that information regarding drainage, site
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 34
maintenance, trees, settlements, and effects of expansive soils be passed on to future all
interested/affected parties. The values tabulated above may not be appropriate to account
for possible differential settlement of the slab due to other factors, such as excessive
settlements. If a stiffer slab is desired, alternative Post-Tensioning Institute ([PTI] third
edition) parameters may be recommended.
Foundation Settlement
Based on the current conceptual design, and provided that the earthwork and foundation
recommendations in this report are adhered, foundations bearing on approved engineered
fill should also be minimally designed to accommodate a total static settlement of 2 inches
and a differential static settlement of 1 inch over a 40-foot horizontal span (angular
distortion = 1/480), and up to ½ inch of seismic differential settlement over a 40-foot
horizontal span (seismic angular distortion = 1/960).
SOIL MOISTURE TRANSMISSION CONSIDERATIONS
GSI has evaluated the potential for vapor or water transmission through the concrete floor
slab, in light of typical floor coverings and improvements. Please note that slab moisture
emission rates range from about 2 to 27 lbs/24 hours/1,000 square feet from a typical slab
(Kanare, 2005), while floor covering manufacturers generally recommend about
3 lbs/24 hours as an upper limit. The recommendations in this section are not intended
to preclude the transmission of water or vapor through the foundation or slabs.
Foundation systems and slabs shall not allow water or water vapor to enter into the
structure so as to cause damage to another building component or to limit the installation
of the type of flooring materials typically used for the particular application (State of
California, 2018). These recommendations may be exceeded or supplemented by a water
“proofing” specialist, project architect, or structural consultant. Thus, the client will need
to evaluate the following in light of a cost vs. benefit analysis (owner expectations and
repairs/replacement), along with disclosure to all interested/affected parties. It should also
be noted that vapor transmission will occur in new slab-on-grade floors as a result of
chemical reactions taking place within the curing concrete. Vapor transmission through
concrete floor slabs as a result of concrete curing has the potential to adversely affect
sensitive floor coverings depending on the thickness of the concrete floor slab and the
duration of time between the placement of concrete, and the floor covering. It is possible
that a slab moisture sealant may be needed prior to the placement of sensitive floor
coverings if a thick slab-on-grade floor is used and the time frame between concrete and
floor covering placement is relatively short.
Considering the E.I. test results presented herein, and known soil conditions in the region,
the anticipated typical water vapor transmission rates, floor coverings, and improvements
(to be chosen by the Client and/or project architect) that can tolerate vapor transmission
rates without significant distress, the following alternatives are provided:
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 35
•Concrete slabs including garages should be more than 5 inches thick.
•Concrete slab underlayment should consist of a 10- to 15-mil vapor retarder, or
equivalent, with all laps sealed per the 2016 CBC and the manufacturer’s
recommendation. The vapor retarder should comply with the ASTM E 1745 -
Class A criteria, and be installed in accordance with ACI 302.1R-04 and ASTM
E 1643.
•The 10- to 15-mil vapor retarder (ASTM E 1745 - Class A) shall be installed per the
recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting,
rebar, etc.).
•Concrete slabs, including the garage areas, shall be underlain by 2 inches of clean,
washed sand (SE > 30) above a 10- to 15-mil vapor retarder (ASTM E-1745 -
Class A, per Engineering Bulletin 119 [Kanare, 2005]) installed per the
recommendations of the manufacturer, including all penetrations (i.e., pipe, ducting,
rebar, etc.). The manufacturer shall provide instructions for lap sealing, including
minimum width of lap, method of sealing, and either supply or specify suitable
products for lap sealing (ASTM E 1745), and per code.
ACI 302.1R-04 (2004) states “If a cushion or sand layer is desired between the
vapor retarder and the slab, care must be taken to protect the sand layer from
taking on additional water from a source such as rain, curing, cutting, or cleaning.
Wet cushion or sand layer has been directly linked in the past to significant
lengthening of time required for a slab to reach an acceptable level of dryness for
floor covering applications.” Therefore, additional observation and/or testing will be
necessary for the cushion or sand layer for moisture content, and relatively uniform
thicknesses, prior to the placement of concrete.
•The vapor retarder should be underlain by at least 2 inches of clean, washed sand
(SE > 30). The sand should be placed on the prepared subgrade described above.
•Concrete should have a maximum water/cement ratio of 0.50. This does not
supercede Table 19.3.2.1 of ACI (2014) for corrosion or other corrosive
requirements. Additional concrete mix design recommendations should be
provided by the structural consultant and/or waterproofing specialist. Concrete
finishing and workablity should be addressed by the structural consultant and a
waterproofing specialist.
•Where slab water/cement ratios are as indicated herein, and/or admixtures used,
the structural consultant should also make changes to the concrete in the grade
beams and footings in kind, so that the concrete used in the foundation and slabs
are designed and/or treated for more uniform moisture protection.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 36
•The homeowners should be specifically advised which areas are suitable for tile
flooring, vinyl flooring, or other types of water/vapor-sensitive flooring and which are
not suitable. In all planned floor areas, flooring shall be installed per the
manufactures recommendations.
•Additional recommendations regarding water or vapor transmission should be
provided by the architect/structural engineer/slab or foundation designer and
should be consistent with the specified floor coverings indicated by the architect.
Regardless of the mitigation, some limited moisture/moisture vapor transmission through
the slab should be anticipated. Construction crews may require special training for
installation of certain product(s), as well as concrete finishing techniques. The use of
specialized product(s) should be approved by the slab designer and water-proofing
consultant. A technical representative of the flooring contractor should review the slab and
moisture retarder plans and provide comment prior to the construction of the foundations
or improvements. The vapor retarder contractor should have representatives onsite during
the initial installation.
WALL DESIGN PARAMETERS
Conventional Retaining Walls
The design parameters provided below assume that either very low expansive soils
(typically Class 2 permeable filter material or Class 3 aggregate base) or native onsite
materials with an E.I. up to 20 are used to backfill any retaining wall (this latter case would
require significant compliance testing). The type of backfill (i.e., select or native), should
be specified by the wall designer, and clearly shown on the plans. Building walls, below
grade, should be water-proofed. The foundation system for the proposed retaining walls
should be designed in accordance with the recommendations presented in this and
preceding sections of this report, as appropriate. Retaining wall footings should be
embedded a minimum of 18 inches below the lowest adjacent grade (excluding landscape
layer, 6 inches [i.e., 24 inches total]) and should be at least 24 inches in width. There
should be no increase in bearing for footing width.
Restrained Walls
Any retaining walls that will be restrained prior to placing and compacting backfill material
or that have re-entrant or male corners, should be designed for an at-rest equivalent fluid
pressure (EFP) of 55 pcf and 65 pcf for select and very low to low expansive native backfill,
respectively. The design should include any applicable surcharge loading. For areas of
male or re-entrant corners, the restrained wall design should extend a minimum distance
of twice the height of the wall (2H) laterally from the corner.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 37
Cantilevered Walls
The recommendations presented below are for cantilevered retaining walls up to 10 feet
high. Design parameters for walls less than 3 feet in height may be superceded by
San Diego Regional Standard design. Active earth pressure may be used for retaining wall
design, provided the top of the wall is not restrained from minor deflections. An equivalent
fluid pressure approach may be used to compute the horizontal pressure against the wall.
Appropriate fluid unit weights are given below for specific slope gradients of the retained
material. These do not include other superimposed loading conditions due to traffic,
structures, seismic events or adverse geologic conditions. When wall configurations are
finalized, the appropriate loading conditions for superimposed loads can be provided upon
request.
For preliminary planning purposes, the structural consultant should incorporate the
surcharge of traffic on the back of retaining walls. The traffic surcharge may be taken as
100 psf/ft in the upper 5 feet of backfill for light truck and car traffic within “H” feet from the
back of the wall, where “H” equals the wall height. This does not include the surcharge
of parked vehicles which should be evaluated at a higher surcharge to account for the
effects of seismic loading.
SURFACE SLOPE OF
RETAINED MATERIAL
(HORIZONTAL:VERTICAL)
EQUIVALENT
FLUID WEIGHT P.C.F.
(SELECT BACKFILL)(2)
EQUIVALENT FLUID WEIGHT
P.C.F. (APPROVED NATIVE
BACKFILL)(3)
Level(1)
2 to 1
38
55
50
65
Level backfill behind a retaining wall is defined as compacted earth materials, properly drained, without(1)
a slope for a distance of 2H behind the w all, where H is the height of the wall.
SE > 30, P.I. < 15, E.I. < 21, and < 10% passing No. 200 sieve.(2)
E.I. = 0 to 20, SE > 25, P.I. < 15, and < 15% passing No. 200 sieve; confirmation testing required.(3)
Seismic Surcharge
For engineered retaining walls that may pose ingress or egress constraints within 6 feet of
a structure, GSI recommends that such walls be evaluated for a seismic surcharge (in
general accordance with 2016 CBC requirements). The site walls in this category should
maintain an overturning Factor-of-Safety (FOS) of approximately 1.25 when the seismic
surcharge (increment), is applied. For restrained walls, the seismic surcharge should be
applied as a uniform surcharge load from the bottom of the footing (excluding shear keys)
to the top of the backfill at the heel of the wall footing. This seismic surcharge pressure
(seismic increment) may be taken as 15H where "H" for retained walls is the dimension
previously noted as the height of the backfill to the bottom of the footing. The resultant
force should be applied at a distance 0.6 H up from the bottom of the footing. For the
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 38
evaluation of the seismic surcharge, the bearing pressure may exceed the static value by
one-third, considering the transient nature of this surcharge. For cantilevered walls the
pressure should be an inverted triangular distribution using 15H. Reference for the seismic
surcharge is Section 1802.2 of the 2016 CBC. Please note this is for local wall stability
only.
The 15H is derived from a Mononobe-Okabe solution for both restrained cantilever walls.
This accounts for the increased lateral pressure due to shakedown or movement of the
sand fill soil in the zone of influence from the wall or roughly a 45/ - N /2 plane away from
the back of the wall. The 15H seismic surcharge is derived from the formula:
hhtP = d C a C (H
hWhere:P =Seismic increment
ha =Probabilistic horizontal site acceleration with a percentage of
“g”
t(=total unit weight (115 to 125 pcf for site soils @ 90% relative
compaction).
H=Height of the wall from the bottom of the footing or point of pile
fixity.
Retaining Wall Backfill and Drainage
Positive drainage must be provided behind all retaining walls in the form of gravel wrapped
in geofabric and outlets. A backdrain system is considered necessary for retaining walls
that are 2 feet or greater in height. Details 1, 2, and 3, present the backdrainage options
discussed below. Backdrains should consist of a 4-inch diameter perforated PVC or ABS
pipe encased in either Class 2 permeable filter material or ¾-inch to 1½-inch gravel
wrapped in approved filter fabric (Mirafi 140N or equivalent). The drain should flow via
gravity to an approved drainage facility. For select backfill, the filter material should extend
a minimum of 1 horizontal foot behind the base of the walls and upward at least 1 foot. For
native backfill that has up to E.I. = 20, continuous Class 2 permeable drain materials
should be used behind the wall. This material should be continuous (i.e., full height)
behind the wall, and it should be constructed in accordance with the enclosed Detail 1
(Typical Retaining Wall Backfill and Drainage Detail). For limited access and confined
areas, (panel) drainage behind the wall may be constructed in accordance with Detail 2
(Retaining Wall Backfill and Subdrain Detail Geotextile Drain). Materials with an expansion
index (E.I.) potential of greater than 20 should not be used as backfill for retaining walls.
For more onerous expansive situations, backfill and drainage behind the retaining wall
should conform with Detail 3 (Retaining Wall And Subdrain Detail Clean Sand Backfill).
Retaining wall backfill should be moisture conditioned to 1.1 times the soil’s optimum
moisture content, placed in relatively thin lifts, and compacted to at least 90 percent of the
laboratory standard (ASTM D 1557).
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 42
Outlets should consist of a 4-inch diameter solid PVC or ABS pipe spaced no greater than
±100 feet apart, with a minimum of two outlets, one on each end. The use of weep holes,
only, in walls higher than 2 feet, is not recommended. The surface of the backfill should
be sealed by pavement or the top 18 inches compacted with native soil (E.I. # 50). Proper
surface drainage should also be provided. For additional mitigation, consideration should
be given to applying a water-proof membrane to the back of all retaining structures. The
use of a waterstop should be considered for all concrete and masonry joints.
Wall/Retaining Wall Footing Transitions
Site walls are anticipated to be founded on footings designed in accordance with the
recommendations in this report. Should wall footings transition from cut to fill, the civil
designer may specify either:
a)A minimum of a 2-foot overexcavation and recompaction of cut materials for a
distance of 2H, from the point of transition.
b)Increase of the amount of reinforcing steel and wall detailing (i.e., expansion joints
or crack control joints) such that a angular distortion of 1/360 for a distance of 2H
on either side of the transition may be accommodated. Expansion joints should be
placed no greater than 20 feet on-center, in accordance with the structural
engineer’s/wall designer’s recommendations, regardless of whether or not transition
conditions exist. Expansion joints should be sealed with a flexible, non-shrink grout.
c) Embed the footings entirely into native formational material (i.e., deepened
footings).
If transitions from cut to fill transect the wall footing alignment at an angle of less than
45 degrees (plan view), then the designer should follow recommendation "a" (above) and
until such transition is between 45 and 90 degrees to the wall alignment.
TOP-OF-SLOPE WALLS/FENCES/IMPROVEMENTS AND EXPANSIVE SOILS
Slope Creep
Some of the soils at the site are likely to be expansive and therefore, become desiccated
when allowed to dry. Such soils are susceptible to surficial slope creep, especially with
seasonal changes in moisture content. Typically in southern California, during the hot and
dry summer period, these soils become desiccated and shrink, thereby developing surface
cracks. The extent and depth of these shrinkage cracks depend on many factors such as
the nature and expansivity of the soils, temperature and humidity, and extraction of
moisture from surface soils by plants and roots. When seasonal rains occur, water
percolates into the cracks and fissures, causing slope surfaces to expand, with a
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 43
corresponding loss in soil density and shear strength near the slope surface. With the
passage of time and several moisture cycles, the outer 3 to 5 feet of slope materials
experience a very slow, but progressive, outward and downward movement, known as
slope creep. For slope heights greater than 7 feet, this creep related soil movement will
typically impact all rear yard flatwork and other secondary improvements that are located
within about 15 feet from the top of slopes, such as swimming pools, concrete flatwork,
etc., and in particular top of slope fences/walls. This influence is normally in the form of
detrimental settlement, and tilting of the proposed improvements. The dessication/swelling
and creep discussed above continues over the life of the improvements, and generally
becomes progressively worse. Accordingly, the developer should provide this information
to all interested/affected parties.
Top of Slope Walls/Fences
Due to the potential for slope creep for slopes higher than about 7 feet, some settlement
and tilting of the walls/fence with the corresponding distresses, should be expected. To
mitigate the tilting of top of slope walls/fences, we recommend that the walls/fences be
constructed on a combination of grade beam and caisson foundations. The grade beam
should be at a minimum of 12 inches by 12 inches in cross section, supported by drilled
caissons, 12 inches minimum in diameter, placed at a maximum spacing of 6 feet on
center, and with a minimum embedment length of 7 feet below the bottom of the grade
beam. The strength of the concrete and grout should be evaluated by the structural
engineer of record. The proper ASTM tests for the concrete and mortar should be
provided along with the slump quantities. The concrete used should be appropriate to
mitigate site corrosion, as warranted. The design of the grade beam and caissons should
be in accordance with the recommendations of the project structural engineer, and include
the utilization of the following geotechnical parameters:
Creep Zone:5-foot vertical zone below the slope face and projected upward
parallel to the slope face.
Creep Load:The creep load projected on the area of the grade beam
should be taken as an equivalent fluid approach, having a
density of 60 pcf. For the caisson, it should be taken as a
uniform 900 pounds per linear foot of caisson’s depth, located
above the creep zone.
Point of Fixity:Located a distance of 1.5 times the caisson’s diameter, below
the creep zone.
Passive Resistance:Passive earth pressure of 300 psf per foot of depth per foot of
caisson diameter, to a maximum value of 4,500 psf may be
used to determine caisson depth and spacing, provided that
they meet or exceed the minimum requirements stated above.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 44
To determine the total lateral resistance, the contribution of the
creep prone zone above the point of fixity, to passive
resistance, should be disregarded.
Allowable Axial Capacity:
Shaft capacity: 350 psf applied below the point of fixity over the surface area
of the shaft.
Tip capacity:4,500 psf.
DRIVEWAY, FLATWORK, AND OTHER IMPROVEMENTS
Some of the soil materials on site are likely to be expansive. The effects of expansive soils
are cumulative, and typically occur over the lifetime of any improvements. On relatively
level areas, when the soils are allowed to dry, the dessication and swelling process tends
to cause heaving and distress to flatwork and other improvements. The resulting potential
for distress to improvements may be reduced, but not totally eliminated. To that end, it is
recommended that the developer should notify all interested/affected parties of this
long-term potential for distress. To reduce the likelihood of distress, the following
recommendations are presented for all exterior flatwork:
1.The subgrade area for concrete slabs should be compacted to achieve a minimum
90 percent relative compaction, and then be presoaked to 1 to 2 percentage points
above (or 110 percent of) the soils’ optimum moisture content, to a depth of
18 inches below subgrade elevation. If very low expansive soils are present, only
optimum moisture content, or greater, is required and specific presoaking is not
warranted. The moisture content of the subgrade should be proof tested within
72 hours prior to concrete placement.
2.Exterior concrete slabs should be cast over a non-yielding surface, consisting of a
4-inch layer of Class 3 base, crushed rock, gravel, or clean sand (or City of Chula
Vista minimum, whichever is greater), that should be compacted and level prior to
placement of concrete. If very low expansive soils are present, the base, rock,
gravel, or sand may be deleted. The layer or subgrade should be wet-down
completely prior to placement of concrete, to minimize loss of concrete moisture to
the surrounding earth materials.
3.Exterior slabs should be a minimum of 4 inches thick. Driveway slabs and
approaches should additionally have a thickened edge (12 inches) adjacent to all
landscape areas, to help impede infiltration of landscape water under the slab.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 45
4.The use of transverse and longitudinal control joints are recommended to help
control slab cracking due to concrete shrinkage or expansion. Two ways to
mitigate such cracking are: a) add a sufficient amount of reinforcing steel,
increasing tensile strength of the slab; and, b) provide an adequate amount of
control and/or expansion joints to accommodate anticipated concrete shrinkage
and expansion.
In order to reduce the potential for unsightly cracks, slabs should be reinforced at
mid-height with a minimum of No. 3 bars placed at 18 inches on center, in each
direction. The exterior slabs should be scored or saw cut, ½ to d inches deep,
often enough so that no section is greater than 10 feet by 10 feet. For sidewalks or
narrow slabs, control joints should be provided at intervals of every 6 feet. The
slabs should be separated from the foundations and sidewalks with expansion joint
filler material.
5.No traffic should be allowed upon the newly poured concrete slabs until they have
been properly cured to within 75 percent of design strength. Concrete compression
strength should be a minimum of 2,500 psi.
6.Driveways, sidewalks, and patio slabs adjacent to the house should be separated
from the house with thick expansion joint filler material. In areas directly adjacent
to a continuous source of moisture (i.e., irrigation, planters, etc.), all joints should
be additionally sealed with flexible mastic.
7.Planters and walls should not be tied to the house.
8.Overhang structures should be supported on the slabs, or structurally designed
with continuous footings tied in at least two directions.
9.Any masonry landscape walls that are to be constructed throughout the property
should be grouted and articulated in segments no more than 20 feet long. These
segments should be keyed or doweled together.
10.Utilities should be enclosed within a closed utilidor (vault) or designed with flexible
connections to accommodate differential settlement and expansive soil conditions.
11.Positive site drainage should be maintained at all times. Finish grade on the lots
should provide a minimum of 1 to 2 percent fall to the street, as indicated herein.
It should be kept in mind that drainage reversals could occur, including
post-construction settlement, if relatively flat yard drainage gradients are not
periodically maintained by the homeowner or homeowners association.
12.Due to expansive soils, air conditioning (A/C) units should be supported by slabs
that are incorporated into the building foundation or constructed on a rigid slab with
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 46
flexible couplings for plumbing and electrical lines. A/C waste water lines should
be drained to a suitable non-erosive outlet.
13.Shrinkage cracks could become excessive if proper finishing and curing practices
are not followed. Finishing and curing practices should be performed per the
Portland Cement Association Guidelines. Mix design should incorporate rate of
curing for climate and time of year, sulfate content of soils, corrosion potential of
soils, and fertilizers used on site.
DEVELOPMENT CRITERIA
Planting
Water has been shown to weaken the inherent strength of all earth materials. Only the
amount of irrigation necessary to sustain plant life should be provided. Over-watering
should be avoided as it can adversely affect site improvements, and cause perched
groundwater conditions. Plants selected for landscaping should be light weight, deep
rooted types that require little water and are capable of surviving the prevailing climate.
Utilizing plants other than those recommended above will increase the potential for
perched water, staining, mold, etc., to develop. A rodent control program to prevent
burrowing should be implemented. These recommendations regarding plant type,
irrigation practices, and rodent control should be provided to all interested/affected parties.
Drainage
Adequate surface drainage is a very important factor in reducing the likelihood of adverse
performance of foundations, hardscape, and slopes. Surface drainage should be sufficient
to mitigate ponding of water anywhere on the property, and especially near structures and
tops of slopes. Surface drainage should be carefully taken into consideration during fine
grading, landscaping, and building construction. Therefore, care should be taken that
future landscaping or construction activities do not create adverse drainage conditions.
Positive site drainage within the property should be provided and maintained at all times.
Drainage should not flow uncontrolled down any descending slope. Water should be
directed away from foundations and not allowed to pond and/or seep into the ground. In
general, site drainage should conform to Section 1804.3 of the 2016 CBC. Consideration
should be given to avoiding construction of planters adjacent to structures (buildings,
pools, spas, etc.). Building pad drainage should be directed toward the street or other
approved area(s). Although not a geotechnical requirement, roof gutters, down spouts,
or other appropriate means may be utilized to control roof drainage. Down spouts, or
drainage devices should outlet a minimum of 5 feet from structures or into a subsurface
drainage system. Areas of seepage may develop due to irrigation or heavy rainfall, and
should be anticipated. Minimizing irrigation will lessen this potential. If areas of seepage
develop, recommendations for minimizing this effect could be provided upon request.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 47
Erosion Control
Slopes will be subject to surficial erosion during and after grading. Onsite earth materials
have a moderate to high erosion potential. Consideration should be given to providing hay
bales and silt fences for the temporary control of surface water, from a geotechnical
viewpoint.
Landscape Maintenance and Planter Design
Only the amount of irrigation necessary to sustain plant life should be provided.
Over-watering the landscape areas will adversely affect proposed site improvements. We
would recommend that any proposed open-bottom planters adjacent to proposed
structures be eliminated for a minimum distance of 10 feet. As an alternative,
closed-bottom type planters could be utilized. An outlet placed in the bottom of the
planter, could be installed to direct drainage away from structures or any exterior concrete
flatwork. If planters are constructed adjacent to structures, the sides and bottom of
the planter should be provided with a moisture retarder to mitigate penetration of irrigation
water into the subgrade. Provisions should be made to drain the excess irrigation
water from the planters without saturating the subgrade below or adjacent to the planters.
Graded slope areas should be planted with drought resistant vegetation. Consideration
should be given to the type of vegetation chosen and their potential effect upon surface
improvements (i.e., some trees will have an effect on concrete flatwork with their extensive
root systems). From a geotechnical standpoint leaching is not recommended for
establishing landscaping. If the surface soils are processed for the purpose of adding
amendments, they should be recompacted to 90 percent minimum relative compaction.
Gutters and Downspouts
As previously discussed in the drainage section, the installation of gutters and downspouts
should be considered to collect roof water that may otherwise infiltrate the soils adjacent
to the structures. If utilized, the downspouts should be drained into PVC collector pipes
or other non-erosive devices (e.g., paved swales or ditches; below grade, solid tight-lined
PVC pipes; etc.), that will carry the water away from the structure, to an appropriate outlet,
in accordance with the recommendations of the design civil engineer. Downspouts and
gutters are not a requirement; however, from a geotechnical viewpoint, provided that
positive drainage is incorporated into project design (as discussed previously).
Subsurface and Surface Water
Subsurface and surface water are not anticipated to affect site development, provided that
the recommendations contained in this report are incorporated into final design and
construction and that prudent surface and subsurface drainage practices are incorporated
into the construction plans. Perched groundwater conditions along zones of contrasting
permeabilities may not be precluded from occurring in the future due to site irrigation, poor
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 48
drainage conditions, or damaged utilities, and should be anticipated. Should perched
groundwater conditions develop, this office could assess the affected area(s) and provide
the appropriate recommendations to mitigate the observed groundwater conditions.
Groundwater conditions may change with the introduction of irrigation, rainfall, or other
factors.
Site Improvements
If in the future, any additional improvements (e.g., pools, spas, etc.) are planned for the
site, recommendations concerning the geological or geotechnical aspects of design and
construction of said improvements could be provided upon request. Preliminary design
and construction recommendations for pools/spas can be provided upon request. This
office should be notified in advance of any fill placement, grading of the site, or trench
backfilling after rough grading has been completed. This includes any grading, utility
trench and retaining wall backfills, flatwork, etc.
Footing Trench Excavation
All footing excavations should be observed by a representative of this firm subsequent to
trenching and prior to concrete form and reinforcement placement. The purpose of the
observations is to evaluate that the excavations have been made into the recommended
bearing material and to the minimum widths and depths recommended for construction.
If loose or compressible materials are exposed within the footing excavation, a deeper
footing or removal and recompaction of the subgrade materials would be recommended
at that time. Footing trench spoil and any excess soils generated from utility trench
excavations should be compacted to a minimum relative compaction of 90 percent, if not
removed from the site.
Trenching/Temporary Construction Backcuts
Considering the nature of the onsite earth materials, it should be anticipated that caving
or sloughing could be a factor in subsurface excavations and trenching. Shoring or
excavating the trench walls/backcuts at the angle of repose (typically 25 to 45 degrees
[except as specifically superceded within the text of this report]), should be anticipated.
All excavations should be observed by an engineering geologist or soil engineer from GSI,
prior to workers entering the excavation or trench, and minimally conform to Cal-OSHA,
state, and local safety codes. Should adverse conditions exist, appropriate
recommendations would be offered at that time. The above recommendations should be
provided to any contractors and/or subcontractors, or property owners, etc., that may
perform such work.
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 49
SUMMARY OF RECOMMENDATIONS REGARDING
GEOTECHNICAL OBSERVATION AND TESTING
We recommend that observation and/or testing be performed by GSI at each of the
following construction stages:
•During grading/recertification.
•During excavation, ground reinforcement, or drilling for shoring, etc.
•During placement of subdrains, toe drains, or other subdrainage devices, prior to
placing fill and/or backfill.
•After excavation of building footings, retaining wall footings, and free standing walls
footings, prior to the placement of reinforcing steel or concrete.
•Prior to pouring any slabs or flatwork, after presoaking/presaturation of building
pads and other flatwork subgrade, before the placement of concrete, reinforcing
steel, capillary break (i.e., sand, pea-gravel, etc.), or vapor retarders (i.e., visqueen,
etc.).
•During retaining wall subdrain installation, prior to backfill placement.
•During placement of backfill for area drain, interior plumbing, utility line trenches,
and retaining wall backfill.
•When any unusual soil conditions are encountered during any construction
operations, subsequent to the issuance of this report.
•When any owner improvements, such as flatwork, spas, pools, walls, etc., are
constructed, prior to construction.
•A report of geotechnical observation and testing should be provided at the
conclusion of each of the above stages, in order to provide concise and clear
documentation of site work, and/or to comply with code requirements.
OTHER DESIGN PROFESSIONALS/CONSULTANTS
The design civil engineer, structural engineer, post-tension designer, architect, landscape
architect, wall designer, etc., should review the recommendations provided herein,
incorporate those recommendations into all their respective plans, and by explicit
reference, make this report part of their project plans. This report presents minimum
design criteria for the design of slabs, foundations and other elements possibly applicable
GeoSoils, Inc.
Quinn Communities W.O. 7393-A-SC
310-316 K Street, Chula Vista February 23, 2018
File:e:\wp12\7300\7393a.pgi Page 50
to the project. These criteria should not be considered as substitutes for actual designs
by the structural engineer/designer. Please note that the recommendations contained
herein are not intended to entirely preclude the transmission of water or vapor through the
slab or foundation. The structural engineer/foundation and/or slab designer should
provide recommendations to not allow water or vapor to enter into the structure so as to
cause damage to another building component, or so as to limit the installation of the type
of flooring materials typically used for the particular application.
If the structural engineer/designer has any questions or requires further assistance, they
should not hesitate to call or otherwise transmit their requests to GSI. In order to mitigate
potential distress, the foundation and/or improvement’s designer should confirm to GSI
and the governing agency, in writing, that the proposed foundations and/or improvements
can tolerate the amount of differential settlement and/or expansion characteristics and
other design criteria specified herein.
PLAN REVIEW
Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.),
should be reviewed by this office prior to construction, so that construction is in
accordance with the conclusions and recommendations of this report. Based on our
review, supplemental recommendations and/or further geotechnical studies may be
warranted.
LIMITATIONS
The materials encountered on the project site and utilized for our analysis are believed
representative of the area; however, soil and bedrock materials vary in character between
excavations and natural outcrops or conditions exposed during mass grading. Site
conditions may vary due to seasonal changes or other factors.
Inasmuch as our study is based upon our review and engineering analyses and laboratory
data, the conclusions and recommendations are professional opinions. These opinions
have been derived in accordance with current standards of practice, and no warranty,
either express or implied, is given. Standards of practice are subject to change with time.
GSI assumes no responsibility or liability for work or testing performed by others, or their
inaction; or work performed when GSI is not requested to be onsite, to evaluate if our
recommendations have been properly implemented. Use of this report constitutes an
agreement and consent by the user to all the limitations outlined above, notwithstanding
any other agreements that may be in place. In addition, this report may be subject to
review by the controlling authorities. Thus, this report brings to completion our scope of
services for this portion of the project. All samples will be disposed of after 30 days, unless
specifically requested by the client, in writing.
APPENDIX A
REFERENCES
GeoSoils, Inc.
APPENDIX A
REFERENCES
Allen, V., Connerton, A., and Carlson, C., 2011, Introduction to Infiltration Best
Management Practices (BMP), Contech Construction Products, Inc.,
Professional Development Series, dated December.
American Society of Civil Engineers, 2014, Supplement No. 2, Minimum design loads for
buildings and other structures, ASCE Standard ASCE/SEI 7-10, dated
September 18.
_____, 2013a, Expanded seismic commentary, minimum design loads for buildings and
other structures, ASCE Standard ASCE/SEI 7-10 (included in third printing).
_____, 2013b, Errata No. 2, minimum design loads for buildings and other structures,
ASCE Standard ASCE/SEI 7-10, dated March 31.
_____, 2013c, Supplement No. 1, minimum design loads for buildings and other structures,
ASCE Standard ASCE/SEI 7-10, dated March 31.
_____, 2010, Minimum design loads for buildings and other structures, ASCE Standard
ASCE/SEI 7-10.
American Society of Civil Engineers, 2010, Minimum design loads for buildings and other
structures, ASCE Standard ASCE/SEI 7-10.
American Society for Testing and Materials (ASTM), 1998, Standard practice for installation
of water vapor retarder used in contact with earth or granular fill under concrete
slabs, Designation: E 1643-98 (Reapproved 2005).
_____, 1997, Standard specification for plastic water vapor retarders used in contact with
soil or granular fill under concrete slabs, Designation: E 1745-97
(Reapproved 2004).
Blake, Thomas F., 2000a, EQFAULT, A computer program for the estimation of peak
horizontal acceleration from 3-D fault sources; Windows 95/98 version.
_____, 2000b, EQSEARCH, A computer program for the estimation of peak horizontal
acceleration from California historical earthquake catalogs; Updated to
January 2015, Windows 95/98 version.
Bozorgnia, Y., Campbell K.W., and Niazi, M., 1999, Vertical ground motion: Characteristics,
relationship with horizontal component, and building-code implications;
Proceedings of the SMIP99 seminar on utilization of strong-motion data,
September 15, Oakland, pp. 23-49.
GeoSoils, Inc.
Quinn Communities Appendix A
File:wp12\7300\7393a.pgi Page 2
California Building Standards Commission, 2016, California Building Code, California Code
of Regulations, Title 24, Part 2, Volume 2 of 2, based on the 2015 International
Building Code, 2016 California Historical Building code, Title 24, Part 8, 2016
California Existing Building Code, Title 24, Part 10, and the 2015 International
Existing Building Code.
California Department of Water Resources, 1993, Division of Safety of Dams, Guidelines
for the design and construction of small embankments dams, reprinted January.
California Geological Survey, 2018, Earthquake Fault Zones, a guide for government
agencies, property owners/developers, and geoscience practitioners for assessing
fault rupture hazards in California, Special Publication 42, revised.
California Stormwater Quality Association (CASQA), 2003, Stormwater best management
practice handbook, new development and redevelopment, dated January.
City of Chula Vista, 2017, 1st Update: Storm Water Standards, part 1: BMP design manual
for permanent site design, storm water treatment and hydromodification
management, dated May
_____, 2015, Storm Water Standards, part 1: BMP design manual for permanent site
design, storm water treatment and hydromodification management, dated
December.
_____, 2015b, BMP design manual, Appendices, dated December
City of San Diego, 2017, Storm water standards, Part 1, BMP design manual: chapters for
permanent site design, storm water treatment and hydromodification management,
dated November.
_____, 2016, Transportation & storm water, storm water standards, Part 1: BMP design
manual - Appendices, dated January.
Clar, M.L., Bartfield, B.J., O’Conner, T.P., 2004, Stormwater best management practice
design guide, volume 3, basin best management practices, US EPA/600/R-04/121B,
dated September.
Hydrologic Solutions, StormChamber installation brochure, pgs. 1 through 8, undated.TM
Jennings, C.W., and Bryant, W.A., 2010, Fault activity map of California, scale 1:750,000,
California Geological Survey, Geologic Data Map No. 6.
Kanare, H.M., 2005, Concrete floors and moisture, Engineering Bulletin 119, Portland
Cement Association.
GeoSoils, Inc.
Quinn Communities Appendix A
File:wp12\7300\7393a.pgi Page 3
Kennedy, M.P., and Tan, SS., 2008, Geologic map of the San Diego 30' by 60' quadrangle,
California, Map no. 3, scale 1:100,000,California Geologic Survey and U.S. Geologic
Survey.
Kennedy, M.P., and Tan, SS., 1977, Geology of National City, Imperial Beach and Otay
Mesa Quadrangles, Southern San Diego Metropolitan Area, California, map sheet
29, scale 1:24,000, California Division of Mines and Geology.
Orion Environmental, Inc., 2016, First Half 2016 Semiannual Groundwater Monitoring
Report, Tesoro Site No. 42069 (Former ARCO Facility No. 5409), 793 3 Avenue,rd
Chula Vista, California, RWQCB Case #9UT1711 (Former SAM Case #H05357-
001), GeoTracker Global ID #T0607300510, P.N. 01TCV, dated July 29.
Post-Tensioning Institute, 2014, Errata to standard requirements for design and analysis
of shallow post-tensioned concrete foundations on expansive soils, PTI DC10.5-12,
dated April 16.
_____, 2013, Errata to standard requirements for design and analysis of shallow
post-tensioned concrete foundations on expansive soils, PTI DC10.5-12, dated
November 12.
_____, 2012, Standard requirements for design and analysis of shallow post-tensioned
concrete foundations on expansive soils, PTI DC10.5-12, dated December.
Romanoff, M., 1957, Underground corrosion, originally issued April 1.
Seed, 2005, Evaluation and mitigation of soil liquefaction hazard “evaluation of field data
and procedures for evaluating the risk of triggering (or inception) of liquefaction. In
‘Geotechnical Earthquake Engineering’; short course, San Diego, California,
April 8-9.
State of California, 2018, Civil Code, Division 2, Part 2, Title 7, Section 895 et seq.
State of California Department of Transportation, Division of Engineering Services,
Materials Engineering, and Testing Services, Corrosion Technology Branch, 2003,
Corrosion Guidelines, Version 1.0, dated September.
Studio E Architects, 2017, 310-316 K Street Study, scale 1"=40', dated November 1.
Tan, S.S., 1995, Landslide hazards in the southern part of the San Diego Metropolitan
area, San Diego County, California, Imperial Beach Quadrangle, Landslide hazard
identification map no. 33, Plate 33G, Department of Conservation, Division of Mines
and Geology, DMG Open File Report 95-03.
GeoSoils, Inc.
Quinn Communities Appendix A
File:wp12\7300\7393a.pgi Page 4
United States Geological Survey, 2011, Seismic hazard curves and uniform hazard
response spectra - v5.1.0, dated February 2
Wire Reinforcement Institute, 1996, Design of slab-on-ground foundations, an update,
dated March.
GeoSoils, Inc.
APPENDIX B
BORING LOGS
UNIFIED SOIL CLASSIFICATION SYSTEM CONSISTENCY OR RELATIVE DENSITY
Major Divisions Group
Symbols Typical Names CRITERIA
Co
a
r
s
e
-
G
r
a
i
n
e
d
S
o
i
l
s
Mo
r
e
t
h
a
n
5
0
%
r
e
t
a
i
n
e
d
o
n
N
o
.
2
0
0
s
i
e
v
e
Gr
a
v
e
l
s
50
%
o
r
m
o
r
e
o
f
co
a
r
s
e
f
r
a
c
t
i
o
n
re
t
a
i
n
e
d
o
n
N
o
.
4
s
i
e
v
e
Cl
e
a
n
Gr
a
v
e
l
s
GW Well-graded gravels and gravel-
sand mixtures, little or no fines Standard Penetration Test
Penetration
Resistance N Relative
(blows/ft) Density
0 - 4 Very loose
4 - 10 Loose
10 - 30 Medium
30 - 50 Dense
> 50 Very dense
GP
Poorly graded gravels and
gravel-sand mixtures, little or no
fines
Gr
a
v
e
l
wi
t
h
GM Silty gravels gravel-sand-silt
mixtures
GC Clayey gravels, gravel-sand-clay
mixtures
Sa
n
d
s
mo
r
e
t
h
a
n
5
0
%
o
f
co
a
r
s
e
f
r
a
c
t
i
o
n
pa
s
s
e
s
N
o
.
4
s
i
e
v
e
Cl
e
a
n
Sa
n
d
s
SW Well-graded sands and gravelly
sands, little or no fines
SP Poorly graded sands and
gravelly sands, little or no fines
Sa
n
d
s
wi
t
h
Fi
n
e
s
SM Silty sands, sand-silt mixtures
SC Clayey sands, sand-clay
mixtures
Fi
n
e
-
G
r
a
i
n
e
d
S
o
i
l
s
50
%
o
r
m
o
r
e
p
a
s
s
e
s
N
o
.
2
0
0
s
i
e
v
e
Si
l
t
s
a
n
d
C
l
a
y
s
Li
q
u
i
d
l
i
m
i
t
50
%
o
r
l
e
s
s
ML
Inorganic silts, very fine sands,
rock flour, silty or clayey fine
sands
Standard Penetration Test
Unconfined
Penetration Compressive
Resistance N Strength
(blows/ft) Consistency (tons/ft
2)
<2 Very Soft <0.25
2 - 4 Soft 0.25 - .050
4 - 8 Medium 0.50 - 1.00
8 - 15 Stiff 1.00 - 2.00
15 - 30 Very Stiff 2.00 - 4.00
>30 Hard >4.00
CL
Inorganic clays of low to
medium plasticity, gravelly clays,
sandy clays, silty clays, lean
clays
OL Organic silts and organic silty
clays of low plasticity
Si
l
t
s
a
n
d
C
l
a
y
s
Li
q
u
i
d
l
i
m
i
t
gr
e
a
t
e
r
t
h
a
n
5
0
%
MH
Inorganic silts, micaceous or
diatomaceous fine sands or silts,
elastic silts
CH Inorganic clays of high plasticity,
fat clays
OH Organic clays of medium to high
plasticity
Highly Organic Soils PT
Peat, mucic, and other highly
organic soils
3" 3/4" #4 #10 #40 #200 U.S. Standard Sieve
Unified Soil
Classification Cobbles
Gravel Sand Silt or Clay
coarse fine coarse medium fine
MOISTURE CONDITIONS MATERIAL QUANTITY OTHER SYMBOLS
Dry Absence of moisture: dusty, dry to the touch trace 0 - 5 % C Core Sample
Slightly Moist Below optimum moisture content for compaction few 5 - 10 % S SPT Sample
Moist Near optimum moisture content little 10 - 25 % B Bulk Sample
Very Moist Above optimum moisture content some 25 - 45 % – Groundwater
Wet Visible free water; below water table Qp Pocket Penetrometer
BASIC LOG FORMAT:
Group name, Group symbol, (grain size), color, moisture, consistency or relative density. Additional comments: odor, presence of roots, mica, gypsum,
coarse grained particles, etc.
EXAMPLE:
Sand (SP), fine to medium grained, brown, moist, loose, trace silt, little fine gravel, few cobbles up to 4" in size, some hair roots and rootlets.
File:Mgr: c;\SoilClassif.wpd PLATE B-1
ACSM/SC
CL
CL
SM
CL
SM
44
34
53
23/
50-3½"
50-6"
98.2
115.4
16.8
13.5
65.0
82.5
@ 0' ASPHALT, 1½ inches thick.
ARTIFICIAL FILL:@ 1½" SILTY SAND/CLAYEY SAND, dark grayish brown,damp, loose; fine gravel, construction debris (concrete, asphalt,brick).@ 3' SANDY CLAY, dark grayish brown, damp, stiff;construction debris (brick and asphalt).@ 4' SANDY CLAY, very dark brown, damp, stiff; fine grainedsand, construction debris (concrete, brick).@ 5' As per 4'.
QUATERNARY OLD PARALIC DEPOSITS:@ 5¾' SANDY CLAYSTONE, dark brown, damp, hard; finegrained sand.
@ 10' SILTY SANDSTONE, light yellowish brown, moist, dense;fine grained.@ 11' CLAYSTONE, dark brown, moist, very stiff; in shoe of 10'sample.
@ 15' SANDY CLAYSTONE, dark brown, wet, hard; fine tocoarse grained sand with trace fine gravel.
@ 20' SILTY SANDSTONE, light yellowish brown with oxidation,dry to damp, very dense; fine grained.
@ 25' SILTY SANDSTONE, light yellowish brown, dry to damp,very dense; fine grained.
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 99' MSL
310-136 K Street, Chula Vista
SHEET OF1BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
B-1
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-1
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
3
De
p
t
h
(
f
t
.
)
SM
SP
SW
SM
33/
50-4½"
31/
50-4"
50-5"
35/
50-4"
@ 30' SILTY SANDSTONE, pale yellow, dry, very dense; finegrained.
@ 35' SANDSTONE, pale yellow to white, dry, very dense; finegrained.
@ 40' SANDSTONE, pale yellow to white, dry, very dense; fineto coarse grained, muscovite mica.
@ 50' SILTY SANDSTONE, light yellowish brown, dry, verydense; fine grained.
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 99' MSL
310-136 K Street, Chula Vista
SHEET OF2BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
B-1
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-2
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
3
De
p
t
h
(
f
t
.
)
50-5½"@ 60' SILTY SANDSTONE, light yellowish brown, damp, verydense; fine grained.Total Depth = 60½'No Caving/Groundwater EncounteredBackfilled 1-25-2018
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 99' MSL
310-136 K Street, Chula Vista
SHEET OF3BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
B-1
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-3
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
3
De
p
t
h
(
f
t
.
)
@ 25' SANDSTONE, yellowish to light grayish brown, dry,medium dense; fine to coarse grained.
ACSM/SCCL/SCCL
SC
SC/CL
CL
SC/CL
SW
43
44
51
37
41
113.4
106.3
107.6
13.3
23.1
2.4
76.5
100
11.8
@ 0' ASPHALT, 2½ inches thick; BASE, 3½ inches thick.
ARTIFICIAL FILL:@ ½' SITLY SAND/CLAYEY SAND, grayish brown, moit, looseto medium dense; fine grained.@ 1' SANDY CLAY/CLAYEY SAND, dark reddish brown, moist,stiff/medium dense; fine grained.@ 1½' SANDY CLAY, dark reddish brown, moist, stiff; finegrained sand, construction debris (concrete, asphalt, brickfragments).
QUATERNARY OLD PARALIC DEPOSITS:@ 3' CLAYEY SANDSTONE, dark reddish brown, moist,medium dense; fine grained.@ 5' CLAYEY SANDSTONE/SANDY CLAYSTONE, brown, wet,medium dense/stiff; fine grained.
@ 10' SANDY CLAYSTONE, dark yellowish brown, moist, hard;fine grained sand.
@ 15' As per 10', saturated.
@ 20' CLAYEY SANDSTONE/SANDY CLAYSTONE, darkyellowish brown, damp, medium dense/hard, fine grained.
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 100' MSL
310-136 K Street, Chula Vista
SHEET OF1BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
B-2
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-4
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
2
De
p
t
h
(
f
t
.
)
@ 30' SILTY SANDSTONE, yellow to light grayish brown, damp,very dense; fine grained.@ 31' SANDSTONE, pale yellow to white, damp, very dense;fine to coarse grained (in shoe of 30' sample).
@ 40' SANDSTONE, yellowish brown to light grayish brown,damp, very dense; fine to coarse grained.Total Depth = 40½'No Caving/Groundwater EncounteredBackfilled 1-25-2018
SM
SW
25/
50-6"
50-6"
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 100' MSL
310-136 K Street, Chula Vista
SHEET OF2BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
B-2
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-5
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
2
De
p
t
h
(
f
t
.
)
ACSM/SC
CL
SC
@ 0' ASPHALT 3½ inches thick; DECOMPOSED GRANITE(DG) BASE 2½ inches thick.
ARTIFICIAL FILL:@ ½' SILTY SAND/CLAYEY SAND, dark grayish brown, damp,loose to medium dense; fine grained, construction debris(concrete, asphaltic, brick fragments).@ 2½' SANDY CLAY, dark reddish brown, damp, stiff; finegrained.@ 4' CLAYEY SAND, dark reddish brown, damp, mediumdense; fine grained.Total Depth = 5'No Caving/Groundwater EncounteredBackfilled 1-26-18
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 100' MSL
310-136 K Street, Chula Vista
SHEET OF1BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
IB-1
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-6
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
1
De
p
t
h
(
f
t
.
)
ACSM/SC
CL
31 108.9 17.4 88.9
@ 0' ASPHALT 3½ inches thick; DECOMPOSED GRANITE(DG) BASE 2½ inches thick.
ARTIFICIAL FILL:@ ½' SILTY SAND/CLAYEY SAND, dark grayish brown, damp,loose to medium dense; fine grained, construction debris(concrete, asphaltic, brick fragments).@ 2½' SANDY CLAY, dark reddish brown, damp, mediumdense; fine grained sand.@ 4' SANDY CLAY, dark brown, wet, very stiff; fine grainedsand, construction debris (asphalt).Total Depth = 5'No Caving/Groundwater EncounteredBackfilled 1-26-18
7393-A-SC
Groundwater
US
C
S
S
y
m
b
o
l
PROJECT:
7393-A-SC
Sample
DATE EXCAVATED
BORING LOG
Seepage
Bl
o
w
s
/
F
t
.
Approx. Elevation: 100' MSL
310-136 K Street, Chula Vista
SHEET OF1BORING
Description of Material
310-136 K Street, Chula Vista
GeoSoils, Inc.
GeoSoils, Inc.
QUINN COMMUNITIES
SAMPLE METHOD:
Un
d
i
s
t
u
r
b
e
d
Mo
i
s
t
u
r
e
(
%
)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
Modified Cal Sampler, 140 lbs @ 30" Drop
Dr
y
U
n
i
t
W
t
.
(
p
c
f
)
IB-2
Sa
t
u
r
a
t
i
o
n
(
%
)
W.O.
PLATE
1-25-18
B-7
Bu
l
k
Standard Penetration Test
Undisturbed, Ring Sample
1
De
p
t
h
(
f
t
.
)
GeoSoils, Inc.
APPENDIX C
SEISMICITY DATA
***********************
* *
* E Q F A U L T *
* *
* Version 3.00 *
* *
***********************
DETERMINISTIC ESTIMATION OF
PEAK ACCELERATION FROM DIGITIZED FAULTS
JOB NUMBER: 7393-A-SC
DATE: 02-15-2018
JOB NAME: QUINN COMMUNITIES
CALCULATION NAME: QUINN COMMUNITIES K STREET
FAULT-DATA-FILE NAME: CDMGFLTE.DAT
SITE COORDINATES:
SITE LATITUDE: 32.6236
SITE LONGITUDE: 117.0745
SEARCH RADIUS: 62.4 mi
ATTENUATION RELATION: 12) Bozorgnia Campbell Niazi (1999) Hor.-Soft Rock-Cor.
UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0
DISTANCE MEASURE: cdist
SCOND: 0
Basement Depth: 5.00 km Campbell SSR: 1 Campbell SHR: 0
COMPUTE PEAK HORIZONTAL ACCELERATION
FAULT-DATA FILE USED: CDMGFLTE.DAT
MINIMUM DEPTH VALUE (km): 3.0
Page 1
W.O. 7393-A-SC
PLATE C-1
---------------
EQFAULT SUMMARY
---------------
-----------------------------
DETERMINISTIC SITE PARAMETERS
-----------------------------
Page 1
-------------------------------------------------------------------------------
| |ESTIMATED MAX. EARTHQUAKE EVENT
| APPROXIMATE |-------------------------------
ABBREVIATED | DISTANCE | MAXIMUM | PEAK |EST. SITE
FAULT NAME | mi (km) |EARTHQUAKE| SITE |INTENSITY
| | MAG.(Mw) | ACCEL. g |MOD.MERC.
================================|==============|==========|==========|=========
ROSE CANYON | 7.0( 11.2)| 6.9 | 0.457 | X
CORONADO BANK | 14.4( 23.2)| 7.4 | 0.335 | IX
NEWPORT-INGLEWOOD (Offshore) | 42.2( 67.9)| 6.9 | 0.083 | VII
ELSINORE-JULIAN | 43.8( 70.5)| 7.1 | 0.091 | VII
EARTHQUAKE VALLEY | 47.6( 76.6)| 6.5 | 0.056 | VI
ELSINORE-COYOTE MOUNTAIN | 47.7( 76.8)| 6.8 | 0.068 | VI
ELSINORE-TEMECULA | 52.2( 84.0)| 6.8 | 0.062 | VI
*******************************************************************************
-END OF SEARCH- 7 FAULTS FOUND WITHIN THE SPECIFIED SEARCH RADIUS.
THE ROSE CANYON FAULT IS CLOSEST TO THE SITE.
IT IS ABOUT 7.0 MILES (11.2 km) AWAY.
LARGEST MAXIMUM-EARTHQUAKE SITE ACCELERATION: 0.4575 g
Page 2
W.O. 7393-A-SC
PLATE C-2
SITE
-100
0
100
200
300
400
500
600
700
800
900
1000
1100
-400 -300 -200 -100 0 100 200 300 400 500 600
CALIFORNIA FAULT MAP
QUINN COMMUNITIES
W.O. 7393-A-SC
PLATE C-3
.001
.01
.1
1
.1 1 10 100
MAXIMUM EARTHQUAKES
QUINN COMMUNITIES
A
c
c
e
l
e
r
a
t
i
o
n
(
g
)
Distance (mi)
W.O. 7393-A-SC
PLATE C-4
*************************
* *
* E Q S E A R C H *
* *
* Version 3.00 *
* *
*************************
ESTIMATION OF
PEAK ACCELERATION FROM
CALIFORNIA EARTHQUAKE CATALOGS
JOB NUMBER: 7393-A-SC
DATE: 02-15-2018
JOB NAME: QUINN COMMUNITIES
EARTHQUAKE-CATALOG-FILE NAME: ALLQUAKE.DAT
SITE COORDINATES:
SITE LATITUDE: 32.6236
SITE LONGITUDE: 117.0745
SEARCH DATES:
START DATE: 1800
END DATE: 2018
SEARCH RADIUS:
62.4 mi
100.4 km
ATTENUATION RELATION: 12) Bozorgnia Campbell Niazi (1999) Hor.-Soft Rock-Cor.
UNCERTAINTY (M=Median, S=Sigma): S Number of Sigmas: 1.0
ASSUMED SOURCE TYPE: SS [SS=Strike-slip, DS=Reverse-slip, BT=Blind-thrust]
SCOND: 0 Depth Source: A
Basement Depth: 5.00 km Campbell SSR: 1 Campbell SHR: 0
COMPUTE PEAK HORIZONTAL ACCELERATION
MINIMUM DEPTH VALUE (km): 3.0
Page 1
W.O. 7393-A-SC
PLATE C-5
-------------------------
EARTHQUAKE SEARCH RESULTS
-------------------------
Page 1
-------------------------------------------------------------------------------
| | | | TIME | | | SITE |SITE| APPROX.
FILE| LAT. | LONG. | DATE | (UTC) |DEPTH|QUAKE| ACC. | MM | DISTANCE
CODE| NORTH | WEST | | H M Sec| (km)| MAG.| g |INT.| mi [km]
----+-------+--------+----------+--------+-----+-----+-------+----+------------
T-A |32.6700|117.1700|10/21/1862| 0 0 0.0| 0.0| 5.00| 0.147 |VIII| 6.4( 10.3)
T-A |32.6700|117.1700|05/24/1865| 0 0 0.0| 0.0| 5.00| 0.147 |VIII| 6.4( 10.3)
T-A |32.6700|117.1700|12/00/1856| 0 0 0.0| 0.0| 5.00| 0.147 |VIII| 6.4( 10.3)
DMG |32.7000|117.2000|05/27/1862|20 0 0.0| 0.0| 5.90| 0.205 |VIII| 9.0( 14.5)
MGI |32.8000|117.1000|05/25/1803| 0 0 0.0| 0.0| 5.00| 0.087 | VII| 12.3( 19.7)
DMG |32.8000|116.8000|10/23/1894|23 3 0.0| 0.0| 5.70| 0.082 | VII| 20.1( 32.3)
MGI |33.0000|117.0000|09/21/1856| 730 0.0| 0.0| 5.00| 0.041 | V | 26.3( 42.4)
DMG |33.0000|117.3000|11/22/1800|2130 0.0| 0.0| 6.50| 0.093 | VII| 29.1( 46.8)
T-A |32.2500|117.5000|01/13/1877|20 0 0.0| 0.0| 5.00| 0.030 | V | 35.8( 57.6)
DMG |32.2000|116.5500|11/05/1949| 43524.0| 0.0| 5.10| 0.026 | V | 42.3( 68.1)
DMG |32.2000|116.5500|11/04/1949|204238.0| 0.0| 5.70| 0.038 | V | 42.3( 68.1)
DMG |32.0830|116.6670|11/25/1934| 818 0.0| 0.0| 5.00| 0.024 | IV | 44.2( 71.2)
DMG |32.7000|116.3000|02/24/1892| 720 0.0| 0.0| 6.70| 0.067 | VI | 45.3( 72.9)
DMG |33.2000|116.7000|01/01/1920| 235 0.0| 0.0| 5.00| 0.023 | IV | 45.3( 72.9)
DMG |33.0000|116.4330|06/04/1940|1035 8.3| 0.0| 5.10| 0.025 | V | 45.4( 73.1)
MGI |33.2000|116.6000|10/12/1920|1748 0.0| 0.0| 5.30| 0.026 | V | 48.4( 77.8)
DMG |32.0000|117.5000|05/01/1939|2353 0.0| 0.0| 5.00| 0.021 | IV | 49.7( 80.0)
DMG |32.0000|117.5000|06/24/1939|1627 0.0| 0.0| 5.00| 0.021 | IV | 49.7( 80.0)
PAS |32.9710|117.8700|07/13/1986|1347 8.2| 6.0| 5.30| 0.024 | IV | 52.0( 83.7)
GSP |32.3290|117.9170|06/15/2004|222848.2| 10.0| 5.30| 0.023 | IV | 53.1( 85.5)
DMG |31.8110|117.1310|12/22/1964|205433.2| 2.3| 5.60| 0.026 | V | 56.2( 90.4)
DMG |31.8670|116.5710|02/27/1937| 12918.4| 10.0| 5.00| 0.017 | IV | 59.9( 96.5)
*******************************************************************************
-END OF SEARCH- 22 EARTHQUAKES FOUND WITHIN THE SPECIFIED SEARCH AREA.
TIME PERIOD OF SEARCH: 1800 TO 2018
LENGTH OF SEARCH TIME: 219 years
THE EARTHQUAKE CLOSEST TO THE SITE IS ABOUT 6.4 MILES (10.3 km) AWAY.
LARGEST EARTHQUAKE MAGNITUDE FOUND IN THE SEARCH RADIUS: 6.7
LARGEST EARTHQUAKE SITE ACCELERATION FROM THIS SEARCH: 0.205 g
COEFFICIENTS FOR GUTENBERG & RICHTER RECURRENCE RELATION:
a-value= 1.328
b-value= 0.529
beta-value= 1.219
------------------------------------
TABLE OF MAGNITUDES AND EXCEEDANCES:
------------------------------------
Earthquake | Number of Times | Cumulative
Magnitude | Exceeded | No. / Year
-----------+-----------------+------------
Page 2
W.O. 7393-A-SC
PLATE C-6
4.0 | 22 | 0.10092
4.5 | 22 | 0.10092
5.0 | 22 | 0.10092
5.5 | 6 | 0.02752
6.0 | 2 | 0.00917
6.5 | 2 | 0.00917
Page 3
W.O. 7393-A-SC
PLATE C-7
SITE
LEGEND
M = 4
M = 5
M = 6
M = 7
M = 8
-100
0
100
200
300
400
500
600
700
800
900
1000
1100
-400 -300 -200 -100 0 100 200 300 400 500 600
EARTHQUAKE EPICENTER MAP
QUINN COMMUNITIES
W.O. 7393-A-SC
PLATE C-8
.001
.01
.1
1
10
100
3.0 3.5 4.0 4.5 5.0 5.5 6.0 6.5 7.0 7.5 8.0 8.5 9.0
EARTHQUAKE RECURRENCE CURVE
QUINN COMMUNITIES
C
u
m
m
u
l
a
t
i
v
e
N
u
m
b
e
r
o
f
E
v
e
n
t
s
(
N
)
/
Y
e
a
r
Magnitude (M)
W.O. 7393-A-SC
PLATE C-9
GeoSoils, Inc.
APPENDIX D
LABORATORY DATA
Tested By: TR Checked By: TR
LIQUID AND PLASTIC LIMITS TEST REPORT
PL
A
S
T
I
C
I
T
Y
I
N
D
E
X
0
10
20
30
40
50
60
LIQUID LIMIT
0 10 20 30 40 50 60 70 80 90 100 110
CL-ML
CL o
r
O
L
CH
o
r
O
H
ML or OL MH or OH
Dashed line indicates the approximate
upper limit boundary for natural soils
4
7
SOIL DATA
SYMBOL SOURCE
NATURAL
USCSSAMPLEDEPTHWATERPLASTICLIQUIDPLASTICITY
NO.CONTENT LIMIT LIMIT INDEX
(%)(%)(%)(%)
Client:
Project:
Project No.:Plate
Quinn Communities
K Street, Chula Vista
7393-A-SC D-1
B-2 B-2 7-10ft 11.2 13 30 17 CL
Tested By: TR Checked By: TR
Client: Quinn Communities
Project: K Street, Chula Vista
Source of Sample: B-1 Depth: 1-4ft
Sample Number: B-1
Proj. No.: 7393-A-SC Date Sampled: 1-25-18
Sample Type: Remolded
Description: Brown Sandy Clay
Specific Gravity= 2.7
Remarks:
Plate D-2
Sample No.
Water Content, %
Dry Density, pcf
Saturation, %
Void Ratio
Diameter, in.
Height, in.
Water Content, %
Dry Density, pcf
Saturation, %
Void Ratio
Diameter, in.
Height, in.
Normal Stress, psf
Fail. Stress, psf
Strain, %
Ult. Stress, psf
Strain, %
Strain rate, in./min.
In
i
t
i
a
l
At
T
e
s
t
Sh
e
a
r
S
t
r
e
s
s
,
p
s
f
0
250
500
750
1000
1250
1500
Strain, %
0 2.5 5 7.5 10
1
2
3
Ul
t
.
S
t
r
e
s
s
,
p
s
f
Fa
i
l
.
S
t
r
e
s
s
,
p
s
f
0
500
1000
1500
Normal Stress, psf
0 500 1000 1500 2000 2500 3000
C, psf
f, deg
Tan(f)
Fail.Ult.
414
24.8
0.46
307
26.2
0.49
1
10.5
111.2
55.0
0.5157
2.38
1.00
18.3
113.8
102.5
0.4808
2.38
0.98
2200
1417
4.8
1381
9.3
0.001
2
10.5
111.2
55.0
0.5157
2.38
1.00
18.3
111.5
96.5
0.5111
2.38
1.00
550
640
2.0
562
4.8
0.001
3
10.5
111.2
55.0
0.5157
2.38
1.00
18.4
113.7
103.1
0.4823
2.38
0.98
1100
965
2.7
871
9.0
0.001
W.O. 7393-A-SC
PLATE D-3
GeoSoils, Inc.
APPENDIX E
INFILTRATION TEST DATA SHEETS
W.O. 7393-A-SC
PLATE E-1
W.O. 7393-A-SC
PLATE E-2
GeoSoils, Inc.
APPENDIX F
INFILTRATION FEASIBILITY WORKSHEET C.4-1
FACTOR OF SAFETY WORKSHEET D.5-1
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-11
Worksheet C.4-1: Categorization of Infiltration Feasibility Condition
Categorization of Infiltration Condition Worksheet C.4-1
Part 1 - Full Infiltration Feasibility Screening Criteria
Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences
that cannot be reasonably mitigated?
Criteria Screening Question Yes No
1
Is the estimated reliable infiltration rate below proposed facility locations greater
than 0.5 inches per hour? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D.
X
Provide basis:
Onsite testing using the inverse auger hole, or “Porchet” method evaluated infiltration rates of less than
0.5 inches per hour. See GSI report dated February 23, 2018 for other related discussions and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
2
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or
other factors) that cannot be mitigated to an acceptable level? The response to this
Screening Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.2.
X
Provide basis:
See the answer to N o. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-12
Worksheet C.4.1 Page 2 of 4
Criteria Screening Question Yes No
3
Can infiltration greater than 0.5 inches per hour be allowed without increasing
risk of groundwater contamination (shallow water table, storm water pollutants
or other factors) that cannot be mitigated to an acceptable level? The response to
this Screening Question shall be based on a comprehensible evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
See the answer to No. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
4
Can infiltration greater than 0.5 inches per hour be allowed without causing
potential water balance issues such as a change of seasonality of ephemeral streams
or increased discharge of contaminated groundwater to surface waters? The
response to this Screening Question shall be based on a comprehensive evaluation of
the factors presented in Appendix C.3.
X
Provide basis:
See the answer to N o. 1.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion
of study/data source applicability.
Part 1
Result*
In the answers to rows 1-4 are “Yes” a full infiltration design is potentially feasible. The feasibility
screening category is Full Infiltration
If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally
be feasible or desirable to achieve a “full infiltration” design.
Proceed to Part 2
Proceed
to Part 2
* 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 [County Engineer] to substantiate findings.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and Groundwater Investigation Requirements
BMP Design Manual-Appendices
December 2015
C-13
Worksheet C.4.1 Page 3 of 4
Part 2 - Partial Infiltration vs. No Infiltration Feasibility Screening Criteria
Would infiltration of water in an appreciable amount be physically feasible without any negative consequences
that cannot be reasonably mitigated?
Criteria Screening Question Yes No
5
Do soil and geologic conditions allow for infiltration in any appreciable
rate or volume? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2 and
Appendix D.
X
Provide basis:
Site specific infiltration testing evaluated infiltration rates (per bio-basin) ranging from 0.031 to 0.064 inches
per hour for onsite soil. The average calculated infiltration rate is ±0.047 inches/hr. Using a minimum FOS
of 2.0, the “reliable infiltration rate” is ±0.02 inches/hr. This is much less than the lower limit of infiltration
recommended by the USEPA (0.52 inches/hr [see Clar, et al., 2004]), and less than that currently allowed
by the City of San Diego (0.05 inches/hr.[see City of San Diego, 2017]). Existing or proposed fill, and/or
moisture sensitive improvements, such as pavements, and utility trench backfill, would likely be adversely
affected, including offsite improvements, causing settlement and distress. See GSI report dated
February 23, 2018 for other related discussions and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
6
Can infiltration in any appreciable quantity be allowed without
increasing risk of geotechnical hazards (slope stability, groundwater
mounding, utilities, or other factors) that cannot be mitigated to an
acceptable level? The response to this Screening Question shall be based on
a comprehensive evaluation of the factors presented in Appendix C.2.
X
Provide basis:
The site is underlain by HSG “D” soils. Bio-basins can adversely affect the performance of the onsite and
offsite structures foundation systems by: 1) Increasing soil moisture transmission rates through concrete
flooring; and 2) Increase the potential for a loss in bearing strength of soil, due to saturation. Onsite
mitigative grading of compressible near-surface soils for the support of structures generally involves
removal and recompaction. This is anticipated to create a permeability contrast, and the potential for the
development of a shallow “perched” and mounded water table, which can reasonably be anticipated to
migrate laterally, beneath the structure(s), or offsite onto adjacent property, causing settlement and
associated distress. . Accordingly, infiltrating into site soils is poor engineering judgement. See GSI report
dated February 23, 2018 for other related discussions, and references.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
GSI Appendix F, W.O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix C,” dated December 2015.
Appendix C:
Geotechnical and G roundw ater Investigation Requirements
BMP Design M anual-Appendices
December 2015
C-14
W orksheet C.4.1 Page 4 of 4
Criteria Screening Question Yes No
7
Can Infiltration in any appreciable quantity be allowed without posing
significant risk for groundwater related concerns (shallow water table,
storm water pollutants or other factors)? The response to this Screening
Question shall be based on a comprehensive evaluation of the factors
presented in Appendix C.3.
X
Provide basis:
Groundwater was not encountered to depths in excess of 60 feet below existing grades in the general
vicinity of these basins. Marquez Auto Body occupies this site, but is not shown on Geotracker as being
impacted. GSI is not aware of surficial contamination at the site; GSI is also unaware if an environmental
assessment of this site has not been performed. Accordingly, it appears that, based on the available data,
there is not a significa nt risk fo r co ntam ina tion to g ro undw a te r; how ever, new info rm a tion co uld cha ng e this
conclusion.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
8
Can infiltration be allow ed w ithout violating downstream water rights?
The response to this Screening Question shall be based on a comprehensive
evaluation of the factors presented in Appendix C.3.
X
Provide basis:
W ater rights are considered a legal matter, and typically do not fall within the purview of geotechnical
engineering. GSI is not aware of any downstream water rights issues of concern on the adjoining
properties. Further, given the low infiltration rate of onsite soils, it does not appear that infiltration should
significantly affect downstream water rights, from a geotechnical perspective. Drainage appears to be
directed offsite and collected within the municipal system.
Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative
discussion of study/data source applicability.
Part 2
Result*
If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The
feasibility screening category is Partial Infiltration.
If any answer from row 5-8 is no, then infiltration of any volume is considered to be
infeasible within the drainage area. The feasibility screening category is No Infiltration.
No
Infiltration
* 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 Agency/Jurisdictions to substantiate findings.
GSI Appendix F, W .O. 7393-A-SC
From “City of Chula Vista, BMP Design Manual: Appendix D,” dated December 2015
Appendix D:
Approved Infiltration Rate Assessment M ethods
BMP Design M anual-Appendicies
December 2015 D-17
W orksheet D.5-1: Factor of Safety and Design Infiltration Rate W orksheet
Factor of Safety Infiltration Rate Worksheet Worksheet D.5-1
Factor Criteria Factor Description Assigned
Weight (w)
Factor
Value (v)
Product (p)
p = w x v
A Suitability
Assessment
Soil assessment methods 0.25 2 0.5
Predominant soil texture 0.25 2 0.5
Site soil variability 0.25 1 0.25
Depth to groundwater/impervious layer 0.25 1 0.25
ASuitability Assessment Safety Factor, S = Ep 1.5 Use 2.0
B Design
Level of pretreatment/expected sediment loads 0.5
Redundancy/resiliency 0.25
Compaction during construction 0.25
BDesign Safety Factor, S = Ep
total A BCombined Safety Factor, S = S x S
observedObserved Infiltration Rate, inch/hr, K
(corrected for test-specific bias)
design observed totalDesign Infiltration Rate, in/hr, K = K / S
Supporting Data
Briefly describe infiltration test and provide reference to test forms:
GeoSoils, Inc.
APPENDIX G
GENERAL EARTHWORK AND GRADING GUIDELINES
AND PRELIMINARY CRITERIA
GeoSoils, Inc.
GENERAL EARTHWORK, GRADING GUIDELINES, AND PRELIMINARY CRITERIA
General
These guidelines present general procedures and requirements for earthwork and grading
as shown on the approved grading plans, including preparation of areas to be filled,
placement of fill, installation of subdrains, excavations, and appurtenant structures or
flatwork. The recommendations contained in the geotechnical report are part of these
earthwork and grading guidelines and would supercede the provisions contained hereafter
in the case of conflict. Evaluations performed by the consultant during the course of
grading may result in new or revised recommendations which could supercede these
guidelines or the recommendations contained in the geotechnical report. Generalized
details follow this text.
The contractor is responsible for the satisfactory completion of all earthwork in accordance
with provisions of the project plans and specifications and latest adopted Code. In the
case of conflict, the most onerous provisions shall prevail. The project geotechnical
engineer and engineering geologist (geotechnical consultant), and/or their representatives,
should provide observation and testing services, and geotechnical consultation during the
duration of the project.
EARTHWORK OBSERVATIONS AND TESTING
Geotechnical Consultant
Prior to the commencement of grading, a qualified geotechnical consultant (soil engineer
and engineering geologist) should be employed for the purpose of observing earthwork
procedures and testing the fills for general conformance with the recommendations of the
geotechnical report(s), the approved grading plans, and applicable grading codes and
ordinances.
The geotechnical consultant should provide testing and observation so that an evaluation
may be made that the work is being accomplished as specified. It is the responsibility of
the contractor to assist the consultants and keep them apprised of anticipated work
schedules and changes, so that they may schedule their personnel accordingly.
All remedial removals, clean-outs, prepared ground to receive fill, key excavations, and
subdrain installation should be observed and documented by the geotechnical consultant
prior to placing any fill. It is the contractor’s responsibility to notify the geotechnical
consultant when such areas are ready for observation.
Laboratory and Field Tests
Maximum dry density tests to determine the degree of compaction should be performed
in accordance with American Standard Testing Materials test method ASTM
designation D 1557. Random or representative field compaction tests should be
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 2
performed in accordance with test methods ASTM designation D 1556, D 2937 or D 2922,
and D 3017, at intervals of approximately ±2 feet of fill height or approximately every 1,000
cubic yards placed. These criteria would vary depending on the soil conditions and the
size of the project. The location and frequency of testing would be at the discretion of the
geotechnical consultant.
Contractor's Responsibility
All clearing, site preparation, and earthwork performed on the project should be conducted
by the contractor, with observation by a geotechnical consultant, and staged approval by
the governing agencies, as applicable. It is the contractor's responsibility to prepare the
ground surface to receive the fill, to the satisfaction of the geotechnical consultant, and to
place, spread, moisture condition, mix, and compact the fill in accordance with the
recommendations of the geotechnical consultant. The contractor should also remove all
non-earth material considered unsatisfactory by the geotechnical consultant.
Notwithstanding the services provided by the geotechnical consultant, it is the sole
responsibility of the contractor to provide adequate equipment and methods to accomplish
the earthwork in strict accordance with applicable grading guidelines, latest adopted
Codes or agency ordinances, geotechnical report(s), and approved grading plans.
Sufficient watering apparatus and compaction equipment should be provided by the
contractor with due consideration for the fill material, rate of placement, and climatic
conditions. If, in the opinion of the geotechnical consultant, unsatisfactory conditions such
as questionable weather, excessive oversized rock or deleterious material, insufficient
support equipment, etc., are resulting in a quality of work that is not acceptable, the
consultant will inform the contractor, and the contractor is expected to rectify the
conditions, and if necessary, stop work until conditions are satisfactory.
During construction, the contractor shall properly grade all surfaces to maintain good
drainage and prevent ponding of water. The contractor shall take remedial measures to
control surface water and to prevent erosion of graded areas until such time as permanent
drainage and erosion control measures have been installed.
SITE PREPARATION
All major vegetation, including brush, trees, thick grasses, organic debris, and other
deleterious material, should be removed and disposed of off-site. These removals must
be concluded prior to placing fill. In-place existing fill, soil, alluvium, colluvium, or rock
materials, as evaluated by the geotechnical consultant as being unsuitable, should be
removed prior to any fill placement. Depending upon the soil conditions, these materials
may be reused as compacted fills. Any materials incorporated as part of the compacted
fills should be approved by the geotechnical consultant.
Any underground structures such as cesspools, cisterns, mining shafts, tunnels, septic
tanks, wells, pipelines, or other structures not located prior to grading, are to be removed
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 3
or treated in a manner recommended by the geotechnical consultant. Soft, dry, spongy,
highly fractured, or otherwise unsuitable ground, extending to such a depth that surface
processing cannot adequately improve the condition, should be overexcavated down to
firm ground and approved by the geotechnical consultant before compaction and filling
operations continue. Overexcavated and processed soils, which have been properly
mixed and moisture conditioned, should be re-compacted to the minimum relative
compaction as specified in these guidelines.
Existing ground, which is determined to be satisfactory for support of the fills, should be
scarified (ripped) to a minimum depth of 6 to 8 inches, or as directed by the geotechnical
consultant. After the scarified ground is brought to optimum moisture content, or greater
and mixed, the materials should be compacted as specified herein. If the scarified zone
is greater than 6 to 8 inches in depth, it may be necessary to remove the excess and place
the material in lifts restricted to about 6 to 8 inches in compacted thickness.
Existing ground which is not satisfactory to support compacted fill should be
overexcavated as required in the geotechnical report, or by the on-site geotechnical
consultant. Scarification, disc harrowing, or other acceptable forms of mixing should
continue until the soils are broken down and free of large lumps or clods, until the working
surface is reasonably uniform and free from ruts, hollows, hummocks, mounds, or other
uneven features, which would inhibit compaction as described previously.
Where fills are to be placed on ground with slopes steeper than 5:1 (horizontal
to vertical [h:v]), the ground should be stepped or benched. The lowest bench, which will
act as a key, should be a minimum of 15 feet wide and should be at least 2 feet deep into
firm material, and approved by the geotechnical consultant. In fill-over-cut slope
conditions, the recommended minimum width of the lowest bench or key is also 15 feet,
with the key founded on firm material, as designated by the geotechnical consultant. As
a general rule, unless specifically recommended otherwise by the geotechnical consultant,
the minimum width of fill keys should be equal to ½ the height of the slope.
Standard benching is generally 4 feet (minimum) vertically, exposing firm, acceptable
material. Benching may be used to remove unsuitable materials, although it is understood
that the vertical height of the bench may exceed 4 feet. Pre-stripping may be considered
for unsuitable materials in excess of 4 feet in thickness.
All areas to receive fill, including processed areas, removal areas, and the toes of fill
benches, should be observed and approved by the geotechnical consultant prior to
placement of fill. Fills may then be properly placed and compacted until design grades
(elevations) are attained.
COMPACTED FILLS
Any earth materials imported or excavated on the property may be utilized in the fill
provided that each material has been evaluated to be suitable by the geotechnical
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 4
consultant. These materials should be free of roots, tree branches, other organic matter,
or other deleterious materials. All unsuitable materials should be removed from the fill as
directed by the geotechnical consultant. Soils of poor gradation, undesirable expansion
potential, or substandard strength characteristics may be designated by the consultant as
unsuitable and may require blending with other soils to serve as a satisfactory fill material.
Fill materials derived from benching operations should be dispersed throughout the fill
area and blended with other approved material. Benching operations should not result in
the benched material being placed only within a single equipment width away from the
fill/bedrock contact.
Oversized materials defined as rock, or other irreducible materials, with a maximum
dimension greater than 12 inches, should not be buried or placed in fills unless the
location of materials and disposal methods are specifically approved by the geotechnical
consultant. Oversized material should be taken offsite, or placed in accordance with
recommendations of the geotechnical consultant in areas designated as suitable for rock
disposal. GSI anticipates that soils to be utilized as fill material for the subject project may
contain some rock. Appropriately, the need for rock disposal may be necessary during
grading operations on the site. From a geotechnical standpoint, the depth of any rocks,
rock fills, or rock blankets, should be a sufficient distance from finish grade. This depth is
generally the same as any overexcavation due to cut-fill transitions in hard rock areas, and
generally facilitates the excavation of structural footings and substructures. Should deeper
excavations be proposed (i.e., deepened footings, utility trenching, swimming pools, spas,
etc.), the developer may consider increasing the hold-down depth of any rocky fills to be
placed, as appropriate. In addition, some agencies/jurisdictions mandate a specific
hold-down depth for oversize materials placed in fills. The hold-down depth, and potential
to encounter oversize rock, both within fills, and occurring in cut or natural areas, would
need to be disclosed to all interested/affected parties. Once approved by the governing
agency, the hold-down depth for oversized rock (i.e., greater than 12 inches) in fills on this
project is provided as 10 feet, unless specified differently in the text of this report. The
governing agency may require that these materials need to be deeper, crushed, or
reduced to less than 12 inches in maximum dimension, at their discretion.
To facilitate future trenching, rock (or oversized material), should not be placed within the
hold-down depth feet from finish grade, the range of foundation excavations, future utilities,
or underground construction unless specifically approved by the governing agency, the
geotechnical consultant, and/or the developer’s representative.
If import material is required for grading, representative samples of the materials to be
utilized as compacted fill should be analyzed in the laboratory by the geotechnical
consultant to evaluate it’s physical properties and suitability for use onsite. Such testing
should be performed three (3) days prior to importation. If any material other than that
previously tested is encountered during grading, an appropriate analysis of this material
should be conducted by the geotechnical consultant as soon as possible.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 5
Approved fill material should be placed in areas prepared to receive fill in near horizontal
layers, that when compacted, should not exceed about 6 to 8 inches in thickness. The
geotechnical consultant may approve thick lifts if testing indicates the grading procedures
are such that adequate compaction is being achieved with lifts of greater thickness. Each
layer should be spread evenly and blended to attain uniformity of material and moisture
suitable for compaction.
Fill layers at a moisture content less than optimum should be watered and mixed, and wet
fill layers should be aerated by scarification, or should be blended with drier material.
Moisture conditioning, blending, and mixing of the fill layer should continue until the fill
materials have a uniform moisture content at, or above, optimum moisture.
After each layer has been evenly spread, moisture conditioned, and mixed, it should be
uniformly compacted to a minimum of 90 percent of the maximum density as evaluated by
ASTM test designation D 1557, or as otherwise recommended by the geotechnical
consultant. Compaction equipment should be adequately sized and should be specifically
designed for soil compaction, or of proven reliability to efficiently achieve the specified
degree of compaction.
Where tests indicate that the density of any layer of fill, or portion thereof, is below the
required relative compaction, or improper moisture is in evidence, the particular layer or
portion shall be re-worked until the required density and/or moisture content has been
attained. No additional fill shall be placed in an area until the last placed lift of fill has been
tested and found to meet the density and moisture requirements, and is approved by the
geotechnical consultant.
In general, per the latest adopted Code, fill slopes should be designed and constructed
at a gradient of 2:1 (h:v), or flatter. Compaction of slopes should be accomplished by
over-building a minimum of 3 feet horizontally, and subsequently trimming back to the
design slope configuration. Testing shall be performed as the fill is elevated to evaluate
compaction as the fill core is being developed. Special efforts may be necessary to attain
the specified compaction in the fill slope zone. Final slope shaping should be performed
by trimming and removing loose materials with appropriate equipment. A final evaluation
of fill slope compaction should be based on observation and/or testing of the finished
slope face. Where compacted fill slopes are designed steeper than 2:1 (h:v), prior
approval from the governing agency, specific material types, a higher minimum relative
compaction, special reinforcement, and special grading procedures will be recommended.
If an alternative to over-building and cutting back the compacted fill slopes is selected,
then special effort should be made to achieve the required compaction in the outer 10 feet
of each lift of fill by undertaking the following:
1.An extra piece of equipment consisting of a heavy, short-shanked sheepsfoot
should be used to roll (horizontal) parallel to the slopes continuously as fill is
placed. The sheepsfoot roller should also be used to roll perpendicular to the
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 6
slopes, and extend out over the slope to provide adequate compaction to the face
of the slope.
2.Loose fill should not be spilled out over the face of the slope as each lift is
compacted. Any loose fill spilled over a previously completed slope face should be
trimmed off or be subject to re-rolling.
3.Field compaction tests will be made in the outer (horizontal) ±2 to ±8 feet of the
slope at appropriate vertical intervals, subsequent to compaction operations.
4.After completion of the slope, the slope face should be shaped with a small tractor
and then re-rolled with a sheepsfoot to achieve compaction to near the slope face.
Subsequent to testing to evaluate compaction, the slopes should be grid-rolled to
achieve compaction to the slope face. Final testing should be used to evaluate
compaction after grid rolling.
5.Where testing indicates less than adequate compaction, the contractor will be
responsible to rip, water, mix, and recompact the slope material as necessary to
achieve compaction. Additional testing should be performed to evaluate
compaction.
SUBDRAIN INSTALLATION
Subdrains should be installed in approved ground in accordance with the approximate
alignment and details indicated by the geotechnical consultant. Subdrain locations or
materials should not be changed or modified without approval of the geotechnical
consultant. The geotechnical consultant may recommend and direct changes in subdrain
line, grade, and drain material in the field, pending exposed conditions. The location of
constructed subdrains, especially the outlets, should be recorded/surveyed by the project
civil engineer. Drainage at the subdrain outlets should be provided by the project civil
engineer.
EXCAVATIONS
Excavations and cut slopes should be examined during grading by the geotechnical
consultant. If directed by the geotechnical consultant, further excavations or
overexcavation and refilling of cut areas should be performed, and/or remedial grading of
cut slopes should be performed. When fill-over-cut slopes are to be graded, unless
otherwise approved, the cut portion of the slope should be observed by the geotechnical
consultant prior to placement of materials for construction of the fill portion of the slope.
The geotechnical consultant should observe all cut slopes, and should be notified by the
contractor when excavation of cut slopes commence.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 7
If, during the course of grading, unforeseen adverse or potentially adverse geologic
conditions are encountered, the geotechnical consultant should investigate, evaluate, and
make appropriate recommendations for mitigation of these conditions. The need for cut
slope buttressing or stabilizing should be based on in-grading evaluation by the
geotechnical consultant, whether anticipated or not.
Unless otherwise specified in geotechnical and geological report(s), no cut slopes should
be excavated higher or steeper than that allowed by the ordinances of controlling
governmental agencies. Additionally, short-term stability of temporary cut slopes is the
contractor’s responsibility.
Erosion control and drainage devices should be designed by the project civil engineer and
should be constructed in compliance with the ordinances of the controlling governmental
agencies, and/or in accordance with the recommendations of the geotechnical consultant.
COMPLETION
Observation, testing, and consultation by the geotechnical consultant should be
conducted during the grading operations in order to state an opinion that all cut and fill
areas are graded in accordance with the approved project specifications. After completion
of grading, and after the geotechnical consultant has finished observations of the work,
final reports should be submitted, and may be subject to review by the controlling
governmental agencies. No further excavation or filling should be undertaken without prior
notification of the geotechnical consultant or approved plans.
All finished cut and fill slopes should be protected from erosion and/or be planted in
accordance with the project specifications and/or as recommended by a landscape
architect. Such protection and/or planning should be undertaken as soon as practical after
completion of grading.
PRELIMINARY OUTDOOR POOL/SPA DESIGN RECOMMENDATIONS
The following preliminary recommendations are provided for consideration in pool/spa
design and planning. Actual recommendations should be provided by a qualified
geotechnical consultant, based on site specific geotechnical conditions, including a
subsurface investigation, differential settlement potential, expansive and corrosive soil
potential, proximity of the proposed pool/spa to any slopes with regard to slope creep and
lateral fill extension, as well as slope setbacks per Code, and geometry of the proposed
improvements. Recommendations for pools/spas and/or deck flatwork underlain by
expansive soils, or for areas with differential settlement greater than ¼-inch over 40 feet
horizontally, will be more onerous than the preliminary recommendations presented below.
The 1:1 (h:v) influence zone of any nearby retaining wall site structures should be
delineated on the project civil drawings with the pool/spa. This 1:1 (h:v) zone is defined
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 8
as a plane up from the lower-most heel of the retaining structure, to the daylight grade of
the nearby building pad or slope. If pools/spas or associated pool/spa improvements are
constructed within this zone, they should be re-positioned (horizontally or vertically) so that
they are supported by earth materials that are outside or below this 1:1 plane. If this is not
possible given the area of the building pad, the owner should consider eliminating these
improvements or allow for increased potential for lateral/vertical deformations and
associated distress that may render these improvements unusable in the future, unless
they are periodically repaired and maintained. The conditions and recommendations
presented herein should be disclosed to all interested/affected parties.
General
1.The equivalent fluid pressure to be used for the pool/spa design should be
60 pounds per cubic foot (pcf) for pool/spa walls with level backfill, and 75 pcf for
a 2:1 sloped backfill condition. In addition, backdrains should be provided behind
pool/spa walls subjacent to slopes.
2.Passive earth pressure may be computed as an equivalent fluid having a density of
150 pcf, to a maximum lateral earth pressure of 1,000 pounds per square foot (psf).
3.An allowable coefficient of friction between soil and concrete of 0.30 may be used
with the dead load forces.
4.When combining passive pressure and frictional resistance, the passive pressure
component should be reduced by one-third.
5.Where pools/spas are planned near structures, appropriate surcharge loads need
to be incorporated into design and construction by the pool/spa designer. This
includes, but is not limited to landscape berms, decorative walls, footings, built-in
barbeques, utility poles, etc.
6.All pool/spa walls should be designed as “free standing” and be capable of
supporting the water in the pool/spa without soil support. The shape of pool/spa
in cross section and plan view may affect the performance of the pool, from a
geotechnical standpoint. Pools and spas should also be designed in accordance
with the latest adopted Code. Minimally, the bottoms of the pools/spas, should
maintain a distance H/3, where H is the height of the slope (in feet), from the slope
face. This distance should not be less than 7 feet, nor need not be greater than
40 feet.
7.The soil beneath the pool/spa bottom should be uniformly moist with the same
stiffness throughout. If a fill/cut transition occurs beneath the pool/spa bottom, the
cut portion should be overexcavated to a minimum depth of 48 inches, and
replaced with compacted fill, such that there is a uniform blanket that is a minimum
of 48 inches below the pool/spa shell. If very low expansive soil is used for fill, the
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 9
fill should be placed at a minimum of 95 percent relative compaction, at optimum
moisture conditions. This requirement should be 90 percent relative compaction
at over optimum moisture if the pool/spa is constructed within or near expansive
soils. The potential for grading and/or re-grading of the pool/spa bottom, and
attendant potential for shoring and/or slot excavation, needs to be considered
during all aspects of pool/spa planning, design, and construction.
8.If the pool/spa is founded entirely in compacted fill placed during rough grading, the
deepest portion of the pool/spa should correspond with the thickest fill on the lot.
9.Hydrostatic pressure relief valves should be incorporated into the pool and spa
designs. A pool/spa under-drain system is also recommended, with an appropriate
outlet for discharge.
10.All fittings and pipe joints, particularly fittings in the side of the pool or spa, should
be properly sealed to prevent water from leaking into the adjacent soils materials,
and be fitted with slip or expandible joints between connections transecting varying
soil conditions.
11.An elastic expansion joint (flexible waterproof sealant) should be installed to prevent
water from seeping into the soil at all deck joints.
12.A reinforced grade beam should be placed around skimmer inlets to provide
support and mitigate cracking around the skimmer face.
13.In order to reduce unsightly cracking, deck slabs should minimally be 4 inches
thick, and reinforced with No. 3 reinforcing bars at 18 inches on-center. All slab
reinforcement should be supported to ensure proper mid-slab positioning during
the placement of concrete. Wire mesh reinforcing is specifically not recommended.
Deck slabs should not be tied to the pool/spa structure. Pre-moistening and/or
pre-soaking of the slab subgrade is recommended, to a depth of 12 inches
(optimum moisture content), or 18 inches (120 percent of the soil’s optimum
moisture content, or 3 percent over optimum moisture content, whichever is
greater), for very low to low, and medium expansive soils, respectively. This
moisture content should be maintained in the subgrade soils during concrete
placement to promote uniform curing of the concrete and minimize the
development of unsightly shrinkage cracks. Slab underlayment should consist of
a 1- to 2-inch leveling course of sand (S.E.>30) and a minimum of 4 to 6 inches of
Class 2 base compacted to 90 percent. Deck slabs within the H/3 zone, where H is
the height of the slope (in feet), will have an increased potential for distress relative
to other areas outside of the H/3 zone. If distress is undesirable, improvements,
deck slabs or flatwork should not be constructed closer than H/3 or 7 feet
(whichever is greater) from the slope face, in order to reduce, but not eliminate, this
potential.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 10
14.Pool/spa bottom or deck slabs should be founded entirely on competent bedrock,
or properly compacted fill. Fill should be compacted to achieve a minimum
90 percent relative compaction, as discussed above. Prior to pouring concrete,
subgrade soils below the pool/spa decking should be throughly watered to achieve
a moisture content that is at least 2 percent above optimum moisture content, to a
depth of at least 18 inches below the bottom of slabs. This moisture content should
be maintained in the subgrade soils during concrete placement to promote uniform
curing of the concrete and minimize the development of unsightly shrinkage cracks.
15.In order to reduce unsightly cracking, the outer edges of pool/spa decking to be
bordered by landscaping, and the edges immediately adjacent to the pool/spa,
should be underlain by an 8-inch wide concrete cutoff shoulder (thickened edge)
extending to a depth of at least 12 inches below the bottoms of the slabs to mitigate
excessive infiltration of water under the pool/spa deck. These thickened edges
should be reinforced with two No. 4 bars, one at the top and one at the bottom.
Deck slabs may be minimally reinforced with No. 3 reinforcing bars placed at
18 inches on-center, in both directions. All slab reinforcement should be supported
on chairs to ensure proper mid-slab positioning during the placement of concrete.
16.Surface and shrinkage cracking of the finish slab may be reduced if a low slump
and water-cement ratio are maintained during concrete placement. Concrete
utilized should have a minimum compressive strength of 4,000 psi. Excessive water
added to concrete prior to placement is likely to cause shrinkage cracking, and
should be avoided. Some concrete shrinkage cracking, however, is unavoidable.
17.Joint and sawcut locations for the pool/spa deck should be determined by the
design engineer and/or contractor. However, spacings should not exceed 6 feet on
center.
18.Considering the nature of the onsite earth materials, it should be anticipated that
caving or sloughing could be a factor in subsurface excavations and trenching.
Shoring or excavating the trench walls/backcuts at the angle of repose (typically
25 to 45 degrees), should be anticipated. All excavations should be observed by
a representative of the geotechnical consultant, including the project geologist
and/or geotechnical engineer, prior to workers entering the excavation or trench,
and minimally conform to Cal/OSHA (“Type C” soils may be assumed), state, and
local safety codes. Should adverse conditions exist, appropriate recommendations
should be offered at that time by the geotechnical consultant. GSI does not consult
in the area of safety engineering and the safety of the construction crew is the
responsibility of the pool/spa builder.
19.It is imperative that adequate provisions for surface drainage are incorporated by
the owner into his/her overall improvement scheme. Ponding water, ground
saturation and flow over slope faces, are all situations which must be avoided to
enhance long term performance of the pool/spa and associated improvements, and
reduce the likelihood of distress.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 11
20.Regardless of the methods employed, once the pool/spa is filled with water, should
it be emptied, there exists some potential that if emptied, significant distress may
occur. Accordingly, once filled, the pool/spa should not be emptied unless
evaluated by the geotechnical consultant and the pool/spa builder.
21.For pools/spas built within (all or part) of the Code setback and/or geotechnical
setback, as indicated in the site geotechnical documents, special foundations are
recommended to mitigate the affects of creep, lateral fill extension, expansive soils
and settlement on the proposed pool/spa. Most municipalities or County reviewers
do not consider these effects in pool/spa plan approvals. As such, where
pools/spas are proposed on 20 feet or more of fill, medium or highly expansive
soils, or rock fill with limited “cap soils” and built within Code setbacks, or within the
influence of the creep zone, or lateral fill extension, the following should be
considered during design and construction:
OPTION A: Shallow foundations with or without overexcavation of the
pool/spa “shell,” such that the pool/spa is surrounded by 5 feet of very low
to low expansive soils (without irreducible particles greater that 6 inches),
and the pool/spa walls closer to the slope(s) are designed to be free
standing. GSI recommends a pool/spa under-drain or blanket system
(see attached Typical Pool/Spa Detail). The pool/spa builders and owner in
this optional construction technique should be generally satisfied with
pool/spa performance under this scenario; however, some settlement, tilting,
cracking, and leakage of the pool/spa is likely over the life of the project.
OPTION B: Pier supported pool/spa foundations with or without
overexcavation of the pool/spa shell such that the pool/spa is surrounded by
5 feet of very low to low expansive soils (without irreducible particles greater
than 6 inches), and the pool/spa walls closer to the slope(s) are designed to
be free standing. The need for a pool/spa under-drain system may be
installed for leak detection purposes. Piers that support the pool/spa should
be a minimum of 12 inches in diameter and at a spacing to provide vertical
and lateral support of the pool/spa, in accordance with the pool/spa
designers recommendations current applicable Codes. The pool/spa builder
and owner in this second scenario construction technique should be more
satisfied with pool/spa performance. This construction will reduce settlement
and creep effects on the pool/spa; however, it will not eliminate these
potentials, nor make the pool/spa “leak-free.”
22.The temperature of the water lines for spas and pools may affect the corrosion
properties of site soils, thus, a corrosion specialist should be retained to review all
spa and pool plans, and provide mitigative recommendations, as warranted.
Concrete mix design should be reviewed by a qualified corrosion consultant and
materials engineer.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 12
23.All pool/spa utility trenches should be compacted to 90 percent of the laboratory
standard, under the full-time observation and testing of a qualified geotechnical
consultant. Utility trench bottoms should be sloped away from the primary structure
on the property (typically the residential structure).
24.Pool and spa utility lines should not cross the primary structure’s utility lines
(i.e., not stacked, or sharing of trenches, etc.).
25.The pool/spa or associated utilities should not intercept, interrupt, or otherwise
adversely impact any area drain, roof drain, or other drainage conveyances. If it is
necessary to modify, move, or disrupt existing area drains, subdrains, or tightlines,
then the design civil engineer should be consulted, and mitigative measures
provided. Such measures should be further reviewed and approved by the
geotechnical consultant, prior to proceeding with any further construction.
26.The geotechnical consultant should review and approve all aspects of pool/spa and
flatwork design prior to construction. A design civil engineer should review all
aspects of such design, including drainage and setback conditions. Prior to
acceptance of the pool/spa construction, the project builder, geotechnical
consultant and civil designer should evaluate the performance of the area drains
and other site drainage pipes, following pool/spa construction.
27.All aspects of construction should be reviewed and approved by the geotechnical
consultant, including during excavation, prior to the placement of any additional fill,
prior to the placement of any reinforcement or pouring of any concrete.
28.Any changes in design or location of the pool/spa should be reviewed and
approved by the geotechnical and design civil engineer prior to construction. Field
adjustments should not be allowed until written approval of the proposed field
changes are obtained from the geotechnical and design civil engineer.
29.Disclosure should be made to the owner and builders, contractors, and any
interested/affected parties, that pools/spas built within about 15 feet of the top of a
slope, and/or H/3, where H is the height of the slope (in feet), will experience some
movement or tilting. While the pool/spa shell or coping may not necessarily crack,
the levelness of the pool/spa will likely tilt toward the slope, and may not be
esthetically pleasing. The same is true with decking, flatwork and other
improvements in this zone.
30.Failure to adhere to the above recommendations will significantly increase the
potential for distress to the pool/spa, flatwork, etc.
31.Local seismicity and/or the design earthquake will cause some distress to the
pool/spa and decking or flatwork, possibly including total functional and economic
loss.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 13
32.The information and recommendations discussed above should be provided to any
contractors and/or subcontractors, or interested/affected parties, etc., that may
perform or may be affected by such work.
JOB SAFETY
General
At GSI, getting the job done safely is of primary concern. The following is the company's
safety considerations for use by all employees on multi-employer construction sites.
On-ground personnel are at highest risk of injury, and possible fatality, on grading and
construction projects. GSI recognizes that construction activities will vary on each site, and
that site safety is the prime responsibility of the contractor; however, everyone must be
safety conscious and responsible at all times. To achieve our goal of avoiding accidents,
cooperation between the client, the contractor, and GSI personnel must be maintained.
In an effort to minimize risks associated with geotechnical testing and observation, the
following precautions are to be implemented for the safety of field personnel on grading
and construction projects:
Safety Meetings: GSI field personnel are directed to attend contractor’s regularly
scheduled and documented safety meetings.
Safety Vests: Safety vests are provided for, and are to be worn by GSI personnel,
at all times, when they are working in the field.
Safety Flags:Two safety flags are provided to GSI field technicians; one is to be
affixed to the vehicle when on site, the other is to be placed atop the
spoil pile on all test pits.
Flashing Lights:All vehicles stationary in the grading area shall use rotating or flashing
amber beacons, or strobe lights, on the vehicle during all field testing.
While operating a vehicle in the grading area, the emergency flasher
on the vehicle shall be activated.
In the event that the contractor's representative observes any of our personnel not
following the above, we request that it be brought to the attention of our office.
Test Pits Location, Orientation, and Clearance
The technician is responsible for selecting test pit locations. A primary concern should be
the technician’s safety. Efforts will be made to coordinate locations with the grading
contractor’s authorized representative, and to select locations following or behind the
established traffic pattern, preferably outside of current traffic. The contractor’s authorized
representative (supervisor, grade checker, dump man, operator, etc.) should direct
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 14
excavation of the pit and safety during the test period. Of paramount concern should be
the soil technician’s safety, and obtaining enough tests to represent the fill.
Test pits should be excavated so that the spoil pile is placed away from oncoming traffic,
whenever possible. The technician's vehicle is to be placed next to the test pit, opposite
the spoil pile. This necessitates the fill be maintained in a driveable condition.
Alternatively, the contractor may wish to park a piece of equipment in front of the test
holes, particularly in small fill areas or those with limited access.
A zone of non-encroachment should be established for all test pits. No grading equipment
should enter this zone during the testing procedure. The zone should extend
approximately 50 feet outward from the center of the test pit. This zone is established for
safety and to avoid excessive ground vibration, which typically decreases test results.
When taking slope tests, the technician should park the vehicle directly above or below the
test location. If this is not possible, a prominent flag should be placed at the top of the
slope. The contractor's representative should effectively keep all equipment at a safe
operational distance (e.g., 50 feet) away from the slope during this testing.
The technician is directed to withdraw from the active portion of the fill as soon as possible
following testing. The technician's vehicle should be parked at the perimeter of the fill in
a highly visible location, well away from the equipment traffic pattern. The contractor
should inform our personnel of all changes to haul roads, cut and fill areas or other factors
that may affect site access and site safety.
In the event that the technician’s safety is jeopardized or compromised as a result of the
contractor’s failure to comply with any of the above, the technician is required, by company
policy, to immediately withdraw and notify his/her supervisor. The grading contractor’s
representative will be contacted in an effort to affect a solution. However, in the interim,
no further testing will be performed until the situation is rectified. Any fill placed can be
considered unacceptable and subject to reprocessing, recompaction, or removal.
In the event that the soil technician does not comply with the above or other established
safety guidelines, we request that the contractor bring this to the technician’s attention and
notify this office. Effective communication and coordination between the contractor’s
representative and the soil technician is strongly encouraged in order to implement the
above safety plan.
Trench and Vertical Excavation
It is the contractor's responsibility to provide safe access into trenches where compaction
testing is needed. Our personnel are directed not to enter any excavation or vertical cut
which: 1) is 5 feet or deeper unless shored or laid back; 2) displays any evidence of
instability, has any loose rock or other debris which could fall into the trench; or 3) displays
any other evidence of any unsafe conditions regardless of depth.
GeoSoils, Inc.
Quinn Communities Appendix G
File:wp12\7300\7392a.pgi Page 15
All trench excavations or vertical cuts in excess of 5 feet deep, which any person enters,
should be shored or laid back. Trench access should be provided in accordance with
Cal/OSHA and/or state and local standards. Our personnel are directed not to enter any
trench by being lowered or “riding down” on the equipment.
If the contractor fails to provide safe access to trenches for compaction testing, our
company policy requires that the soil technician withdraw and notify his/her supervisor.
The contractor’s representative will be contacted in an effort to affect a solution. All backfill
not tested due to safety concerns or other reasons could be subject to reprocessing and/or
removal.
If GSI personnel become aware of anyone working beneath an unsafe trench wall or
vertical excavation, we have a legal obligation to put the contractor and owner/developer
on notice to immediately correct the situation. If corrective steps are not taken, GSI then
has an obligation to notify Cal/OSHA and/or the proper controlling authorities.