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Technical Report 10 - Storm Water Quality Management Plan
Approved By: City of Chula Vista Date: (print Name & Sign) Otay Ranch Town Center 643-061-0500, 0400, 0800, TM22-0002 TBD Alisa S. Vialpando 47945 Brookfield Properties 733 Eighth Avenue San Diego, CA 92101 (619) 321-1130 Hunsaker & Associates SD, Inc. 9707 Waples Street San Diego, CA 92121 (858) 558-4500 02/09/2023 Otay Ranch Town Center Otay Ranch Town Center Otay Ranch Town Center Otay Ranch Town Center TM22-0002 47945 12/31/23 Alisa S. Vialpando Hunsaker & Associates SD, Inc. Otay Ranch Town Center 01/22/2012 02/27/22 07/29/22 02/10/23 Changing the site design Second submittal Third Submittal Otay Ranch Town Center Otay Ranch Town Center Storm Water Requirements Applicability Checklist for All Permit Applications Intake Form March 2019 Update Project Information Project Address:Project Application # Project Name:APN(s) Brief Description of Work Proposed: The project is (select one): New Development Total Impervious Area _________________ ft2 Redevelopment Total new and/or replaced Impervious Area __________________ ft2 (Redevelopment is the creation and/or replacement of impervious surface on an already developed site). Others __________________________________________________________ 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 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: Repair or improvements to an existing building or structure that alter the size such as: tenant improvements, interior remodeling, electrical work, fire alarm, fire sprinkler system, HVAC work, Gas, plumbing, etc. Routine maintenance activities such as: roof or exterior structure surface replacement; resurfacing existing roadways and parking lots including dig outs, 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 & page 2. No Continue to Section 2, page 3. 2015 Birch Rd, Chula Vista, CA 91915 TM22-0002 Otay Ranch Town Center The redevelopment will predominately consist of multi- family residential dwelling units, Plaza with associated streets and utility infrastructure 643-061-0500, 0400, 0800 AVialpando@HunsakerSD.com (858) 558-4500 06-18-2020 443,358 Alisa Vialpando, PE Construction Storm Water BMP Certification Statement The following stormwater quality protection measures are required by City Chula Vista Municipal Code Chapter 14.20 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 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: __________________________ Section 2: Determine if Project is a Standard Project or Priority Development Project Is the project in any of the following categories, (a) through (j)? (a)New development that creates 10,000 square feet or more of impervious 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 projects that creates and/or replaces a combined total of 5,000 square feet or more of impervious surface (collectively over the entire project site) and support one or more of the following uses: Yes No (i)Restaurant. This 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). (ii)Hillside development projects. This category includes development on any natural slope that is twenty-five percent or greater. (iii)Parking Lots. 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. (iv)Streets, roads, highways, freeways, and driveways. This category is defined as any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. (d)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 ncludes flow that is conveyed overland a distance of 200 feet or less from the project to the 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 New development or redevelopment project that creates and/or replaces a combined total of 5,000 square feet or more of impervious surface, that support one or more of the following used: Yes No (i) Automotive repair shops. 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. (ii) Retail gasoline outlets. This category includes retail gasoline outlets that meet the meet one of the following criteria: (a) 5,000 square feet or more or (b) a projected Average Daily Traffic (ADT) of 100 or more vehicles per day. New development or redevelopment that result in the disturbance of one or more acres of land and are expected to generate pollutants post construction.This does not include projects creating less than 5,000 sf of impervious surface and where added landscaping does not require regular use of pesticides and fertilizers, such as slope stab ilization using native plants. Calculation of the square footage of impervious surface need not include linear pathways that are for infrequent vehicle use, such as emergency maintenance access or bicycle pedestrian use, if they are built with pervious surfaces of if they sheet flow to surrounding pervious surfaces. Yes No The project is (select one): 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. ,P (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 __________________ ft2 (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: Are designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non- erodible permeable areas? Or; Are designed and constructed to be hydraulically disconnected from paved streets or roads? Or; 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. 449,534 472,389 105 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. Otay Ranch Town Center Not Applicable Otay Ranch Town Center ` Otay Ranch Town Center Otay Ranch Town Center 2015 Birch Rd, Chula Vista, CA 91915 643-061-0500, 0400, 0800, TM22-0002 16.59 16.59 12.16 4.43 10 Otay Ranch Town Center The site in its exiting condition consists of surface parking, driveways, a temporary recreation center and an open space. The site’s existing land cover consists of parking\ drive ways impervious area, open space not vegetated area, and temporary recreation area Otay Ranch Town Center The existing drainage conveyance is urban. The offsite runoff is collected via inlets and catch basins offsite and conveyed via stormdrain lines through the site. In Existing condition, the Otay Ranch Town Center site generally flows in a southwesterly direction to be picked up by inlets and catch basins. The collected runoff is routed via three storm drain lines running from north to south to join off site of the redeveloped area and discharge to a single connection point to the public storm drain system in Birch Road. The storm water then is conveyed to the Poggi Canyon Detention Basin for peak storm attenuation, which ultimately discharges into Otay River, 4.5 miles southwest of the study area. The re-development will predominately consist of three residential buildings with maximum of 840 residential units with a plaza building, associated streets, sidewalks and utility infrastructure. The gross project area is approximately 16.59 acres including all high density resi- dential areas as well as plaza area. Development of site will include impervious features such as buildings (residential, plaza), streets, driveways, and sidewalks. The site will include pervious areas including landscaped areas The site will require regrading the site, Grading of pads and streets will slightly alter the current drainage patterns. Grading and improvements will include the construction of streets which will generally drain towards the southwest to the vault. Otay Ranch Town Center Otay Ranch Town Center Redevelopment of the site will include construction of storm drain improvements including pipes, inlets, cleanouts, detention underground facilitie with riser structures. There are no additional drainage structures for offsite conveyance since offsite runoff is generally not routed through the site. In general, onsite drainage is collected via inlets and conveyed within the storm drain system within the streets. The conveyance system direction is towards the underground vault which will discharge into the existing storm drain east and west of the vault. The discharge from the vault will be conveyed similarly to the existing conditions via storm drain lines running from north to south to join off site of the redeveloped area and discharge to a single connection point to the public storm drain system in Birch Rd. The storm water then is conveyed to the Poggi Canyon Detention Basin for peak storm attenuation, which ultimately discharges into Otay River, 4.5 miles southwest of the study area. Otay Ranch Town Center The development will consist of single and multi-family residential, and community purpose facility (CPF) development. The BMPs above reflect the proposed source control BMPs which are typically applicable to this type of development. The site will include inlet stenciling for public awareness of pollution concerns related to street pollutants. The use of pesticides for landscape use will be discouraged and designated refuse areas (where applicable) will be protected from stormwater. Not Applicable since the MWS unit is designed as proprietary biofiltration Runoff from the site will be collected via area drain, inlets and catch basins. The majority of runoff is conveyed by storm drain towards the proposed water quality biofiltration MWS unit/ detention and HMP underground vault prior to discharging into existing storm drains. A small portion of 2nd Street will leave the site and be cap- tured by two 4x4 filterra units before connecting to the existing storm drain. The runoff leaving the redeveloped area will continue in the existing storm drains south to join before discharging into the public storm drain in Birch Rd. Runoff then is conveyed to Poggi Canyon then to Otay River and eventually into San Diego Bay Poggi Canyon Creek Nitrogen, Toxicity Otay Valley HA ,Trash & bacteria San Diego Bay Mercury, PAHs and PCBs Bacteria Otay Ranch Town Center Otay Ranch Town Center No critical coarse sediment yield areas to be protected based on WMAA maps Otay Ranch Town Center The site has one designated point of compliance (POC1) which is coincident with the single connection point where the site storm drain join before discharging into the public storm drain at Birch Rd. Otay Ranch Town Center Otay Ranch Town Center Project Name: _____________________________________________________ Otay Ranch Town Center Project Name: _____________________________________________________ Otay Ranch Town Center Otay Ranch Town Center Project Name.: _______________________________________________________ Otay Ranch Town Center Project Name/Address/N ______________________________________________ Otay Ranch Town Center Treatment of onsite stormwater will be treated via the proposed proprietary biofiltration MWS units. This site design is not feasible for this project. Otay Ranch Town Center Volume-based Proprietary Biofiltration Otay Ranch Town Center BF-3-1 Alisa S. Vialpando , PE # 47945 Hunsaker & Associates SD, Inc. 9707 Waples St, San Diego,CA 92121 (858) 558-4500 HOA for Otay Ranch Town Center HOA for Otay Ranch Town Center Rent and fees to the Homeowners Association (HOA) for Otay Ranch Town Center Otay Ranch Town Center BF-3-1 * 85th percentile 24-hr storm depth from iso map Figure B.1.1 is d =0.53 in *The area drains to the biofiltration Proprietary MWS unit is delineated A= 645559 sf * Total impervious area is 466909 sf, and pervious area is 177669 sf *The weighted area runoff factor is calculated as a composite coefficient made of the different runoff factor for the surfaces of the DMA area per equation C ={( 0.9 * Impervious surfaces )+ (0.1 * pervious areas)} / (total area) C = {(0.9*466909)+(0.1*177669)}/ (645559)= 0.679 * Calculate DCV = 3630 x C x d x A = 3630 x 0.679 x 0.53 x (645559/43560)= 19349 cft 1.5 DCV = 29023.5 cft * A portion of the underground vault will be used as WQ storage to store the 1.5 DCV and release it in a rate to drawdown in 36 hr and not exceed the HMP max allowable low flow *2 8 x 16 MWS unit is used to treat the required volume and draw down in 36 hrs Otay Ranch Town Center HMP-1 Alisa S. Vialpando , PE # 47945 Hunsaker & Associates SD, Inc. 9707 Waples St, San Diego,CA 92121 (858) 558-4500 HOA for Otay Ranch Town Center HOA for Otay Ranch Town Center Rent and fees to the Homeowners Association (HOA) for Otay Ranch Town Center Otay Ranch Town Center HMP-1 Determine the required HMP volume using the BMP Sizing spread sheet V.3.1 Flow-based Proprietary Biofiltration Otay Ranch Town Center BF-3-2 Alisa S. Vialpando , PE # 47945 Hunsaker & Associates SD, Inc. 9707 Waples St, San Diego,CA 92121 (858) 558-4500 HOA for Otay Ranch Town Center HOA for Otay Ranch Town Center Rent and fees to the Homeowners Association (HOA) for Otay Ranch Town Center Otay Ranch Town Center BF-3-2 * 85th percentile 24-hr storm depth from iso map Figure B.1.1 is d =0.53 in *The area drains to the biofiltration Proprietary MWS unit is delineated A= 10289 sf * Total impervious area is 8030 sf, and pervious area is 2258 sf *The weighted area runoff factor is calculated as a composite coefficient made of the different runoff factor for the surfaces of the DMA area per equation C ={( 0.9 * Impervious surfaces )+ (0.1 * pervious areas)} / (total area) C = {(0.9*8030)+(0.1*2258)}/ (10289)= 0.724 * Calculate DCV = 3630 x C x d x A = 3630 x 0.724 x 0.53 x (10289/43560)= 329 cft * 4 x 4 Filterra unit is used to treat the required flow. Flow-based Proprietary Biofiltration Otay Ranch Town Center BF-3-3 Alisa S. Vialpando , PE # 47945 Hunsaker & Associates SD, Inc. 9707 Waples St, San Diego,CA 92121 (858) 558-4500 HOA for Otay Ranch Town Center HOA for Otay Ranch Town Center Rent and fees to the Homeowners Association (HOA) for Otay Ranch Town Center Otay Ranch Town Center BF-3-3 * 85th percentile 24-hr storm depth from iso map Figure B.1.1 is d =0.53 in *The area drains to the biofiltration Proprietary MWS unit is delineated A= 5306 sf * Total impervious area is 4208 sf, and pervious area is 1098 sf *The weighted area runoff factor is calculated as a composite coefficient made of the different runoff factor for the surfaces of the DMA area per equation C ={( 0.9 * Impervious surfaces )+ (0.1 * pervious areas)} / (total area) C = {(0.9*4208)+(0.1*1098)}/ (5306)= 0.734 * Calculate DCV = 3630 x C x d x A = 3630 x 0.734 x 0.53 x (5304/43560)=172 cft * 4 x 4 Filterra unit is used to treat the required flow. Otay Ranch Town Center Otay Ranch Town Center Otay Ranch Town Center ATTACHMENT 1a DMA EXHIBIT NORTH AVE. T O W N C E N T E R D R . ( N O R T H B O U N D ) T O W N C E N T E R D R . ( S O U T H B O U N D ) DMA 2 BF-3-3 FILTERRA DMA 1 BF -3-1 STORAGE FACILITY HMP -1 MWS 2N D S T R E E T BF-3-2 DMA 3 FILTERRA LOT 1 LOT AREA:1.50 AC. PAD AREA:1.45 AC. LOT W LOT AREA:0.74 AC. PAD AREA: 0.71 AC. NORTH AVE. T O W N C E N T E R D R . ( N O R T H B O U N D ) T O W N C E N T E R D R . ( S O U T H B O U N D ) 2N D S T R E E T LOT 2 LOT AREA:1.18 AC. PAD AREA:1.10 AC. LOT 3 LOT AREA:1.81 AC. PAD AREA:1.71 AC. LOT 4 LOT AREA:1.81 AC. PAD AREA:1.63 AC. LOT 9 LOT AREA:0.47 AC. PAD AREA:0.42 AC. LOT 6 LOT AREA:0.73 AC. PAD AREA:0.69 AC. LOT 8 LOT AREA:1.17 AC. PAD AREA:1.13 AC. LOT 7 LOT AREA:1.19 AC. PAD AREA:1.14 AC. LOT 5 LOT AREA:0.73 AC. PAD AREA:0.69 AC. BIRCH ROAD LOT G LOT AREA:0.38 AC. PAD AREA:0.36 AC. LOT F LOT AREA:0.87 AC. PAD AREA:0.70 AC. OTAY TOWN CENTER HUNSAKER& ASSOCIATES PREPARED BY: CITY CHULA VISTA, CALIFORNIA OF 2 1DMA MAPTHE JOIN POINT OF STORM DRAIN LINES BEFORE DISCHARGING INTO PUBLIC STORM DRAIN AT BIRCH RD POC BELOW IS AROUND OF THE PROJECT900' SOUTH LEGEND: PROJECT BOUNDARY........................................................................................... DMA BOUNDARY.................................................................................................... DAYLIGHT............................................................................................................... PROPOSED STORM DRAIN.................................................................................. EXISTING STORM DRAIN...................................................................................... FLOW LINE............................................................................................................. SUBAREA ACREAGE............................................................................................. DMA ICON............................................................................................................... IMPERVIOUS - ROAD............................................................................................ IMPERVIOUS - SIDEWALK.................................................................................... PERVIOUS AREAS................................................................................................. LOTS 1 AND 2......................................................................................................... LOTS 3 AND 4......................................................................................................... LOTS 5, 6, 7, AND 8................................................................................................ LOT 9....................................................................................................................... UNDERGROUND STORAGE FACILITY................................................................. MWS UNIT.............................................................................................................. TRENCHING & RESURFACING............................................................................ EX. IMPREVIOUSNESS DRAINING TO BMPS.................................................... INLET...................................................................................................................... HYDROLOGIC SOIL TYPE..................................................................................... POINT OF COMPLIANCE....................................................................................... STRUCTURAL BMP\ MWS UNIT............................................................................ SYMBOL: SITE DESIGN BMPs: SD-3 MINIMIZE IMPERVIOUS AREAS SD-4 MINIMIZE SOIL COMPACTION SD-5 IMPERVIOUS AREA DISPERSION SD-7 LANDSCAPING WITH NATIVE OR DROUGHT TOLERANT SPECIES SD-8 HARVESTING AND USING PRECIPITATION SOURCE CONTROL BMPs: SC-1 PREVENTION OF ILLICIT DISCHARGES TO MS4 SC-2 STORM DRAIN STENCILING OR SIGNAGE SC-5 PROTECT TRASH STORAGE AREAS SC-6 ADDITIONAL BMPS BASED ON POTENTIAL SOURCES OF RUNOFF POLLUTANTS SC-6A ON-SITE STORM DRAIN INLETS SC-6C INTERIOR PARKING GARAGES SC-6D NEED FOR FUTURE INDOOR & STRUCTURAL PEST CONTROL SC-6E LANDSCAPE/OUTDOOR PESTICIDE USE SC-6F POOLS, SPAS, PONDS, FOUNTAINS, AND OTHER WATER FEATURES SC-6Q PLAZAS, SIDEWALKS, AND PARKING LOTS UNDERLYING SOIL GROUP : C & D APPROXIMATE DEPTH TO GROUNDWATER > 20' NO CRITICAL COARSE AREAS REQUIRE PRESERVATION DMA 1 PARK NOTE: WORK WITHIN LOT E WILL INCLUDES RESURFACING OF IMPERVIOUS AREAS AND LANDSCAPE RENOVATIONS. THE BASE SHALL REMAIN IN PLACE. THE RENOVATIONS WILL INCLUDE AN INCREASE IN PERVIOUS AREAS; THE NEW LANDSCAPE AREAS WILL BE IN ISLANDS AND CAN BE COUNTED AS SELF-RETAINING. NO WATER QUALITY MEASURES ARE EXPECTED TO BE IMPLEMENTED OR NEEDED. SEE RIGHT FOR LOT G AND F SEE LEFT FOR LOT 10 PARK NOTE: WORK WITHIN LOT F INCLUDES THE RENOVATION OF A DOG PARK CREATING MORE PERVIOUS AREAS BY INCREASING THE LANDSCAPE IN THE LOT. WORK WITHIN LOT G INCLUDES THE REMOVING ON PARKING AND CREATION OF A SMALL PARK/LANDSCAPE AREA. DISPERSION AREAS AND AMENDED SOILS WILL BE USED AS THE WATER QUALITY TREATMENT METHOD FOR THESE TWO AREAS. DUE TO THE EARLY STAGE OF THE PROJECT, THE DISPERSION AREAS WILL BE DETERMINED DURING FINAL ENGINEERING. DISPERSION AREAS AND AMENDED SOILS NOTE: DISPERSION AREAS AND AMENDED SOILS WILL BE DETERMINED DURING FINAL ENGINEERING. THESE AREAS WILL BE REQUIRED TO BE SHOWN ON FUTURE PLANS. LOT 10 LOT 1 LOT 5 LOT 7 LOT 8 LOT 6 LOT 9 LOT 2 LOT 3 LOT 4 LOT A LOT B LOT C LOT D LOT I LOT H LOT E LOT 10 LOT F LOT G PROJECT BOUNDARY PROPOSED DMA BOUNDARY DAYLIGHT FLOW DIRECTION AREA HYDROLOGIC SOIL TYPE EXISTING IMPERVIOUS AREA EXISITNG STORM DRAIN LEGEND DMA 1 EXISTING IMPERVIOUS AREA = 10.3 AC OTAY TOWN CENTER HUNSAKER& ASSOCIATES PREPARED BY: CITY CHULA VISTA, CALIFORNIA OF 2 2EXISTING DMA MAP STANDARD DETAIL STORMWATER BIOFILTRATION SYSTEM MWS-L-8-16-6'-0"-V-UG SITE SPECIFIC DATA PLAN VIEW ELEVATION VIEW RIGHT END VIEW LEFT END VIEW GENERAL NOTES INSTALLATION NOTES STANDARD DETAIL STORMWATER BIOFILTRATION SYSTEM MWS-L-8-16-6'-0"-V-UG SITE SPECIFIC DATA PLAN VIEW ELEVATION VIEW RIGHT END VIEW LEFT END VIEW GENERAL NOTES INSTALLATION NOTES ATTACHMENT 1b TABULAR SUMMARY OF DMAs Project Name: _____________________________________________________ Tabular Summary of DMAs Worksheet B-1 DMA Unique Identifier Area (acres) Impervious Area (acres) % Imp HSG Area Weighted Runoff Coefficient DCV (Cubic feet) Treated by (BMP ID) Pollutant Control Type Drains to (POC ID) Summary of DMA Information (Must match Project description and SWQMP narrative) No. of DMAs Total DMA Area (acres) Total Impervious Area (acres) % Impervious Area Weighted Runoff Coefficient DCV (Cubic feet) Total Area Treated (acres) No. of POCs Otay Ranch Town Center DMA 1 14.82 10.72 72.48 D/C 19349 BF-3-1 BIOFILTR 1 DMA 2 DMA 3 0.24 0.12 0.18 0.10 78.05 79.30 D D 0.724 0.734 329 172 BF-3-2 BF-3-3 BIOFILTRL BIOFILTRL 1 1 0.679 Imp. RF Pervious RF-D % Imp DMA 1 Fraction of Total Imp Area Pervious Area Summation RF x A DMA 2 Fraction of Total Imp Area Pervious Area Summation RF x A DMA 3 Fraction of Total Imp Area Pervious Area Summation RF x A SQFT SQFT SQFT SQFT SQFT SQFT SQFT SQFT SQFT PERVIOUS 0.90 0.10 0 74018 0.02 0 74018 7402 2258 0.03 0 2258 226 1098 0.03 0 1098 110 SIDEWALK 0.90 0.10 100 15593 0.03 15593 0 14033 1365 0.16 1365 0 1229 917 0.21 917 0 825 ROADS 0.90 0.10 100 96134 0.20 96134 0 86521 6665 0.80 6665 0 5999 3291 0.76 3291 0 2962 EX IMP/RESURFACING 0.90 0.10 VARIES 17021 0.03 17021 0 15319 N/A ----0 0.00 0 0 0 LOT 1-2 PERVIOUS 0.90 0.10 0 31622 0.01 0 31622 3162 N/A ----N/A ---- LOT 1-2 IMPERVIOUS 0.90 0.10 100 81886 0.17 81886 0 73697 N/A ----N/A ---- LOT 3-4 PERVIOUS 0.90 0.10 0 40436 0.01 0 40436 4044 N/A ----N/A ---- LOT 3-4 IMPERVIOUS 0.90 0.10 100 110234 0.23 110234 0 99211 N/A ----N/A ---- LOT 5-8 PERVIOUS 0.90 0.10 0 31593 0.01 0 31593 3159 N/A ----N/A ---- LOT 5-8 IMPERVIOUS 0.90 0.10 100 127391 0.26 127391 0 114652 N/A ----N/A ---- LOT 9 PERVIOUS 0.90 0.10 0 982 0.00 0 982 98 N/A LOT 9 IMPERVIOUS 0.90 0.10 100 18650 0.04 18650 0 16785 N/A ----N/A ---- 645559 1.00 466909 178651 438083 10289 1.00 8030 2258 7453 5306 1.00 4208 1098 3897 %Imperv 72.33 Weighted C =0.679 78.05 Weighted C =0.724 79.30 Weighted C =0.734 ATTACHMENT 1c FORM I-7, HARVEST AND USE FEASIBLITY SCREENING CHECKLIST Harvest and Use Feasibility Checklist Form I-7 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.4.2. 3. Calculate the DCV using worksheet B-2.1. DCV = 78,435 (cubic feet) 0.25DCV=19,609 cubic feet 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. 36 hr toilet use per resident= 1.5 x 9.3 gal/resident x 700 residents= 9,765 gallons= 1305 cf, 36 hour landscape use/acre= 196.52 cf/ac x 7.031 ac= 1382 cf Total anticipated 36 hr use = 2687 cf 㔲ㄳ 904 12610 1881 1010 2891 ATTACHMENT 1d FORM I-8, CATEGORIZATION OF INFILTRATION FEASIBILITY CONDITION INFILTRATION FEASIBILITY CONDITION LETTER OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA PREPARED FOR JULY 28, 2022 PROJECT NO. G2883-52-01 Project No. G2883-52-01 July 28, 2022 Brookfield Properties 733 8th Avenue San Diego, California 92101 Attention: Mr. Dan Buoye Subject: INFILTRATION FEASIBILITY CONDITION LETTER LOGAN YARDS APARTMENTS SOUTH 16TH STREET AND NATIONAL AVENUE SAN DIEGO, CALIFORNIA Reference: Geotechnical Reconnaissance Report, Otay Ranch Town Center, Chula Vista, California, prepared by Geocon Incorporated, dated February 4, 2022 (Project No. G2883-52-01). Dear Mr. Buoye: In accordance with the request of Mr. Alejandro Chavez Gonzales with Hunsaker & Associates San Diego, we prepared this report regarding storm water management for the subject project. The site is located north of Birch Road and the Otay Ranch Town Center Mall, south of Olympic Parkway and the Planning Area 12 development, west of Eastlake Parkway and east of State Route 125 in the City of Chula Vista, California (see Vicinity Map). Vicinity Map Geocon Project No. G2883-52-01 - 2 - July 28, 2022 SITE DESCRIPTION The existing property consists of the northern parking area for the existing Otay Ranch Town Center mall. The area consists of surface grade asphalt concrete parking on the east and southwest, an outdoor soccer area and playground in the central portion with a landscape construction storage area in the northwest portion. The site was graded between 2004 and 2005 with observation and testing services provided by Geotechnics, Incorporated. The site is relatively flat with elevations between 624 feet Mean Sea Level (MSL) and 614 feet MSL, descending gently to the southwest. An existing 10- to 15-foot-high cut and fill slope exists on the west limits of the site that descends towards State Route 125. The Existing Site Map shows the current conditions at the site. Based on the previous as-graded map, the site was partially situated over the upper portions of two canyon drainages with fill depths ranging up to about 25 feet at the site. Existing Site Map PROJECT DESCRIPTION We understand the proposed redevelopment will consist of constructing 3, multi-family residential lots with commercial space, reconfiguring the existing Town Center Drive entrance and installing a new Geocon Project No. G2883-52-01 - 3 - July 28, 2022 plaza area in the southeast portion of the site with accommodating utilities, flatwork, and landscaping. The Preliminary Site Plan shows a current concept of the proposed improvements. Preliminary Site Plan The locations and descriptions of the site and proposed development are based on the referenced site plan and our understanding of project development. If project details vary significantly from those described herein, Geocon Incorporated should be contacted to evaluate the necessity for review and revision of this report. STORM WATER FEASIBILITY Below is the specific information requested from Section C.1.1 of the 2021 City of Chula Vista BMP Design Manual. The Phase of the Project In which the geotechnical engineer first analyzed the site for infiltration feasibility: The current design is in the entitlement phase but this report can be used for both the entitlement and design phases. Geocon Project No. G2883-52-01 - 4 - July 28, 2022 Results of previous geotechnical analyses conducted in the project area, if any. Based on our referenced report, the property is underlain by previously placed fill with a thickness of up to about 25 feet overlying Otay Formation. We expect groundwater exists deeper than 100 feet below the existing grade. The development status of the site prior to the project application. The property was graded between 2004 and 2005 to construct the northern parking area for the existing Otay Ranch Town Center mall. The area consists of surface grade asphalt concrete parking on the east and southwest, an outdoor soccer area and playground in the central portion with a landscape construction storage area in the northwest portion. Prior to grading, which included placing up to about 25 feet of fill, the site was partially situated over the upper portions of two canyon drainages. The history of design discussion for the project footprint, resulting the final design determination. We evaluated the site conditions for infiltration with the project civil engineer. Based on the existing geologic conditions, we opine infiltration should not be considered for the property. An underground storm water storage facility and modular wetlands system are planned that do not allow infiltration. Full/partial infiltration BMP standard setbacks to underground utilities, structures, retaining walls, fill slopes, and natural slopes applicable to the DMA that prevent full/partial infiltration. Most of the property is underlain by compacted fill that is used to support the existing improvements. The fill materials were not designed to allow for infiltration (i.e. compacted to a dry density of at least 90 percent of the laboratory maximum dry density and contain a mixture of fine- and coarse-grained materials). Existing utilities are located within the adjacent public right-of-way to the north of the site and the drive lanes that transect the site. A descending slope exists on the western portion of the property. Full or partial infiltration should not be allowed in the areas of the fill, utilities and slope areas to help prevent potential damage/distress to improvements. Mitigation measures to prevent water from infiltrating the utilities consist of setbacks, installing cutoff walls around the utilities and installing subdrains and/or installing liners. The horizontal and vertical setbacks for infiltration devices should be a minimum of 10 feet and a 1:1 plane of 1 foot below the closest edge of the deepest adjacent utility, respectively. An existing 10- to 15-foot-high cut and fill slope exists on the west limits of the site, descending towards State Route 125. The setback for infiltration devices should be a minimum distance of 50 feet and 1.5H from fill slopes where H is the height of the fill slope. Physical impairments (i.e., fire road egress, public safety considerations, etc.) that prevent full/partial infiltration. The Otay Ranch Town Center mall exists adjacent to the south property margin. Infiltration near buildings and improvements should not be allowed, nor should any BMP devices that would prevent or limit access to existing structures. Consideration of site design alternative to achieve partial/full infiltration within the DMA. Based on the existing fill materials, utilities and slopes, full and partial infiltration should not be allowed on the property. Geocon Project No. G2883-52-01 - 5 - July 28, 2022 The extent site design BMPs requirements were included in the overall design. BMPs, including an underground storage facility and Modular Wetlands System are being incorporated into the site design for storm water management. These devices should not allow infiltration into the surrounding soil. Conclusion or recommendation from the geotechnical engineer regarding the DMA’s infiltration condition. The property is underlain by up to approximately 25 feet of previously placed fill materials Based the discussion herein, we opine full and partial infiltration is considered infeasible at the site. We recommend storm water management BMPs be designed so that infiltration does not occur. An Exhibit for all applicable DMA’s that clearly labels: Proposed development areas and development type. All applicable features and setbacks that prevent partial or full infiltration, including underground utilities, structures, retaining walls, fill slopes, natural slopes, and existing fill materials greater than 5 feet. Potential locations for structural BMPs. Areas where full/partial infiltration BMPs cannot be proposed. The Geologic Map, Figure 1, is presented as a base map. The figure shows the proposed development area and proposed buildings and improvements, and the area on the site infeasible to infiltration due to existing fill, utilities/improvements, slope areas and property line limits. We opine the entire project site is infeasible for infiltration. If you have any questions regarding this letter, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Shawn Foy Weedon GE 2714 SFW:kv (e-mail) Addressee B-8 B-7 B-6 B-11 B-10 B-12 B-13 B-2 B-3 B-1 B-5 B-4 B-9 (3') (3') (5'+) (9.5') (4') (6') (5'+) (5'+) (15.5') (6') (5'+) (18.5') (5'+) To Qpf/ Qpf/ Qpf/ Qpf/ Qpf/ 605 604 602 602 609 606 600 594 606611 613 606 613 601 608 611 616 612 616 617 615 621 614 610 613 604 602 613 604 602 603 608 To To To 620 614 606 ? ? ? ? ? ? To APPROX. SITE LIMITS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF PROJECT NO. SCALE DATE FIGURE Plotted:02/04/2022 8:53AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\G2883-52-01 (OR Town Center)\SHEETS\G2883-52-01 Geo Map.dwg GEOTECHNICAL ENVIRONMENTAL MATERIALS 1" = GEOLOGIC MAP OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA 60'02 - 04 - 2022 G2883 - 52 - 01 1 1 1 ........PREVIOUSLY PLACED FILL (Geotechnics, Inc. 2005) ........OTAY FORMATION (Dotted Where Buried) ........APPROX. LOCATION OF GEOLOGIC CONTACT ........APPROX. LOCATION OF BORING (Geocon, Inc. 2014) ........APPROX. DEPTH OF FILL (In Feet) ........APPROX. ELEVATION AT BASE OF FILL (In Feet, MSL) GEOCON LEGEND 613 Qpf B-13 To (5'+) .......NO INFILTRATION DUE TO EXISTING UTILITIES, IMPROVEMENTS, AND PROPERTY LINE LIMITS (OUTSIDE FILL AREAS) .......NO INFILTRATION DUE TO EXISTING FILL 5+ FT. 30 ' - 6 " PROPOSED BUILDING 1 PROPOSED BUILDING 2 PROPOSED BUILDING 3 60'-0" .......NO INFILTRATION DUE TO EXISTING SLOPE 07-28-2022 Geocon Project No. G2883-52-01 July 28, 2022 LIST OF REFERENCES 1.City of Chula Vista (2021), BMP Design Manual, dated March 2019, updated August 2021. 2.Geocon Incorporated (2022), Geotechnical Reconnaissance Report, Otay Ranch Center, Chula Vista, California, prepared by Geocon Incorporated, dated February 4, 2022 (Project No. G2883-52-01). 3.Geocon Incorporated (2014), Preliminary Geotechnical Investigation, Otay Ranch Town Center Addition, Otay Ranch Village 12, 2015 Birch Road, Chula Vista, California, prepared by Geocon Incorporated, dated June 26, 2014 (Project No. G1731-11-01). 4.Geotechnics Incorporated (2006), As-Graded Geotechnical Report, McMillin Otay Ranch, Village 12 and Borrow and Fill Sites Within the Eastern Urban Center, Chula Vista, California, prepared by Geotechnics Incorporated, dated February 16, 2006 (Project No. 0367-012-01, Document No. 05-1029). 5.Todd, V. R. (2004), Preliminary Geologic Map of the El Cajon 30’x60’ Quadrangle, Southern California, Version 1.0, Open-File Report 2004-1361 Scale 1:100,000 6.Unpublished reports, aerial photographs, and maps on file with Geocon Incorporated. ATTACHMENT 1e POLLUTION CONTROL BMP DESIGN WORKSHEETS Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods BMP Design Manual-Appendices B-6 March 2019 Update Figure B.1-1: 85th Percentile 24-hour Isopluvial Map Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods BMP Design Manual-Appendices B-45 August 2021 Update (b) The retention losses from the optimized biofiltration BMP are equal to or greater than the retention losses from the conventional biofiltration BMP. This second criterion is only applicable for partial infiltration condition. For drawdown times that are outside the range of values presented in Table B.5-5 below, the storage unit should be designed to discharge greater than 92% average annual capture to the downstream Biofiltration BMP. Table B.5-5: Storage required for different drawdown times Drawdown Time (hours) Storage requirement (below the overflow elevation, or below outlet elevation that bypass the biofiltration BMP) 12 0.85 DCV 24 1.25 DCV 36 1.50 DCV 48 1.80 DCV 72 2.20 DCV 96 2.60 DCV 120 2.80 DCV Imp. RF Pervious RF-D % Imp DMA 1 Fraction of Total Imp Area Pervious Area Summation RF x A DMA 2 Fraction of Total Imp Area Pervious Area Summation RF x A DMA 3 Fraction of Total Imp Area Pervious Area Summation RF x A SQFT SQFT SQFT SQFT SQFT SQFT SQFT SQFT SQFT PERVIOUS 0.90 0.10 0 74018 0.02 0 74018 7402 2258 0.03 0 2258 226 1098 0.03 0 1098 110 SIDEWALK 0.90 0.10 100 15593 0.03 15593 0 14033 1365 0.16 1365 0 1229 917 0.21 917 0 825 ROADS 0.90 0.10 100 96134 0.20 96134 0 86521 6665 0.80 6665 0 5999 3291 0.76 3291 0 2962 EX IMP/RESURFACING 0.90 0.10 VARIES 17021 0.03 17021 0 15319 N/A ----0 0.00 0 0 0 LOT 1-2 PERVIOUS 0.90 0.10 0 31622 0.01 0 31622 3162 N/A ----N/A ---- LOT 1-2 IMPERVIOUS 0.90 0.10 100 81886 0.17 81886 0 73697 N/A ----N/A ---- LOT 3-4 PERVIOUS 0.90 0.10 0 40436 0.01 0 40436 4044 N/A ----N/A ---- LOT 3-4 IMPERVIOUS 0.90 0.10 100 110234 0.23 110234 0 99211 N/A ----N/A ---- LOT 5-8 PERVIOUS 0.90 0.10 0 31593 0.01 0 31593 3159 N/A ----N/A ---- LOT 5-8 IMPERVIOUS 0.90 0.10 100 127391 0.26 127391 0 114652 N/A ----N/A ---- LOT 9 PERVIOUS 0.90 0.10 0 982 0.00 0 982 98 N/A LOT 9 IMPERVIOUS 0.90 0.10 100 18650 0.04 18650 0 16785 N/A ----N/A ---- 645559 1.00 466909 178651 438083 10289 1.00 8030 2258 7453 5306 1.00 4208 1098 3897 %Imperv 72.33 Weighted C =0.679 78.05 Weighted C =0.724 79.30 Weighted C =0.734 1 85th percentile 24-hr storm depth from Figure B.1-1 d=0.53 inches 2 Area tributary to BMP (s)A=14.82 acres 3 Area weighted runoff factor (estimate using Appendix B.1.1 and B.2.1) C=0.679 unitless 4 Street trees volume reduction TCV=0.00 cubic-feet 5 Rain barrels volume reduction RCV=0.00 cubic-feet 6 Calculate DCV= (3630 x C x d x A) - TCV - RCV DCV=19,349 cubic-feet 1 85th percentile 24-hr storm depth from Figure B.1-1 d=0.53 inches 2 Area tributary to BMP (s)A=0.24 acres 3 Area weighted runoff factor (estimate using Appendix B.1.1 and B.2.1) C=0.724 unitless 4 Street trees volume reduction TCV=0.00 cubic-feet 5 Rain barrels volume reduction RCV=0.00 cubic-feet 6 Calculate DCV= (3630 x C x d x A) - TCV - RCV DCV=329 cubic-feet 1 85th percentile 24-hr storm depth from Figure B.1-1 d=0.53 inches 2 Area tributary to BMP (s)A=0.12 acres 3 Area weighted runoff factor (estimate using Appendix B.1.1 and B.2.1) C=0.734 unitless 4 Street trees volume reduction TCV=0.00 cubic-feet 5 Rain barrels volume reduction RCV=0.00 cubic-feet 6 Calculate DCV= (3630 x C x d x A) - TCV - RCV DCV=172 cubic-feet DMA 1: Design Capture Volume Worksheet B-2.1 DMA 2: Design Capture Volume Worksheet B-2.1 DMA 3: Design Capture Volume Worksheet B-2.1 Project Name BMP ID 1 645559.20 sq. ft. 2 0.68 3 0.53 inches 4 19349 cu. ft. 5 0 in/hr. 6 2 7 0 in/hr. 10 445 cu. ft. Area draining to the BMP Otay Town Center BF-1 Sizing Method for Volume Retention Worksheet B.5-2 %When Line 7 > 0.01 in/hr. = Minimum (40, 166.9 x Line 7 +6.62) When Line 7 ≤ 0.01 in/hr. = 3.5% Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) 85th percentile 24-hour rainfall depth Design capture volume [Line 1 x Line 2 x (Line 3/12)] Volume Retention Requirement Measured infiltration rate in the DMA Note: When mapped hydrologic soil groups are used enter 0.10 for NRCS Type D soils and for NRCS Type C soils enter 0.30 When in no infiltration condition and the actual measured infiltration rate is unknown enter 0.0 if there are geotechnical and/or groundwater hazards identified in Appendix C or enter 0.05 Factor of safety Reliable infiltration rate, for biofiltration BMP sizing [Line 5 / Line 6] 8 Average annual volume reduction target (Figure B.5-2) 3.5 9 Fraction of DCV to be retained (Figure B.5-3) 0.023 When Line 8 > 8% = 0.0000013 x Line 83 - 0.000057 x Line 82 + 0.0086 x Line 8 - 0.014 When Line 8 ≤ 8% = 0.023 Target volume retention [Line 9 x Line 4] 1 645559.20 sq. ft. 2 0.68 3 2 lb/sq. ft. 4 0.5 years Fraction of Total DCV 0 0 0 0 0 0 0.66 0.29 0.05 5 34.54 mg/L 7 12.8 inches 8 467288 cu-ft/yr 10 252 sq. ft. Discussion: Average Annual Precipitation was determined using the GIS layes for it from SanGIS. Calculate the BMP Footprint Needed (Line 9 x Line 4)/Line 3 11 Calculate the Minimum Footprint Sizing Factor for Clogging 0.000575[ Line 10/ (Line 1 x Line 2)] Average Annual Precipitation [Provide documentation of the data source in the discussion box; SanGIS has a GIS layer for average annual precipitation] Calculate the Average Annual Runoff (Line 7/12) x Line 1 x Line2 9 Calculate the Average Annual TSS Load 1007 lb/yr(Line 8 x 62.4 x Line 5 x (1 – Line 6))/106 Volume Weighted EMC (sum of all products) Sizing Factor for Clogging 6 Adjustment for pretreatment measures 0Where: Line 6 = 0 if no pretreatment; Line 6 = 0.25 when pretreatment is included; Line 6 = 0.5 if the pretreatment has an active Washington State TAPE approval rating for “pre-treatment.” Other, specify:0 Other, specify:0 Open Space 216 10.8 Other, specify:0 Roof Runoff 14 9.24 Low Traffic Areas 50 14.5 Transportation 78 0 Multi-family Residential 40 0 Industrial 125 0 Education (Municipal)132 0 Single Family Residential 123 0 Commercial 128 0 Area draining to the BMP Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) Load to Clog (default value when using Appendix E fact sheets is 2.0) Allowable Period to Accumulate Clogging Load (TL) (default value is 10) Volume Weighted EMC Calculation Land Use TSS EMC (mg/L)Product Project Name Otay Town Center BMP ID BF-1 Alternative Minimum Footprint Sizing Factor for Worksheet B.5-4 Project Name BMP ID 1 645559.20 sq. ft. 2 0.68 3 438082.8116 sq. ft. 4 18,904 cu. ft. 5 0 ft./hr. 6 1.666666667 ft. 7 8.333333 ft./hr. 8 0.05 in/in 9 36 hours 10 1.5 fraction 11 28355.45758 cu. ft. 12 29400 cu. ft. 13 Is Line 12 ≥ Line 11? 14 0.4142 cfs 15 179 sq. ft. 16 0.000575 fraction 17 252 sq. ft. 18 cu. ft. 19 cfs 20 0 ft 21 0 sq. ft. 22 252 sq. ft. Required optimized biofiltration footprint (Line 18/Line 20) Optimized Biofiltration Footprint Optimized biofiltration footprint, maximum(Line 15, Line 17, Line 21) Alternative Minimum Footprint Sizing Factor [Line 11 of Worksheet B.5-4] Required biofiltration footprint [Line 3 x Line 16] Criteria 3: Retention requirement [Not applicable for No Infiltration Condition] Retention Target (Line 10 in Worksheet B.5-2) Average discharge rate from the storage unit to the biofiltration BMP Depth retained in the optimized biofiltration BMP {Line 6 x Line 8} + {[(Line 4)/(2400 x Line 19)] x Line 5} Storage provided in the design, minimum(from the elevation that bypasses the biofiltration BMP, overflow elevation) Storage Requirement is Met Criteria 1: BMP Footprint Biofiltration Capacity Peak flow from the storage unit to the biofiltration BMP (using the elevation used to evaluate the percent capture) Required biofiltration footprint [(3,600 x Line 14)/Line 7] Criteria 2: Alternative Minimum Sizing Factor (Clogging) Media filtration rate to be used for sizing (0.42 ft/hr. with no outlet control; if the filtration rate is controlled by the outlet use the outlet controlled rate) Media retained pore space Storage Unit Requirement Drawdown time of the storage unit, minimum(from the elevation that bypasses the biofiltration BMP, overflow elevation) Storage required to achieve greater than 92 percent capture (see Table B.5-5) Storage required in cubic feet (Line 4 x Line 10) Area draining to the storage unit and biofiltration BMP Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) Effective impervious area draining to the storage unit and biofiltration BMP [Line 1 x Line 2] Remaining DCV after implementing retention BMPs Design infiltration rate (measured infiltration rate / 2) Media thickness [1.5 feet minimum], also add mulch layer and washed ASTM 33 fine aggregate sand thickness to this line for sizing calculations Otay Town Center BF-1 Optimized Biofiltration BMP Footprint when Downstream of a Storage Unit Worksheet B.5-5 Project Name BMP ID 1 sq. ft. 2 3 sq. ft. 4 sq. ft. 5 sq. ft. Identification 1 4 5 6 13500 7 20250 10 sq. ft. 11 sq. ft. 12 13 14 cu. ft. 15 cu. ft. Identification 1 cu. ft. 2 cu. ft. 3 cu. ft. 4 cu. ft. 5 cu. ft. cu. ft. 17 Area draining to the biofiltration BMP 645559.20 Otay Town Center BF-1 Volume Retention for No Infiltration Condition Worksheet B.5-6 Landscape area that meet the requirements in SD-B and SD-F Fact Sheet (sq. ft.) Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)0.68 Effective impervious area draining to the BMP [Line 1 x Line 2]438083 Required area for Evapotranspiration [Line 3 x 0.03]13142 Biofiltration BMP Footprint 256 Landscape Area (must be identified on DS-3247) 2 3 Impervious area draining to the landscape area (sq. ft.) 8 Impervious to Pervious Area ratio 1.50 0.00 0.00 Volume Retention Performance Standard 0.00 0.00[Line 7/Line 6] 9 Effective Credit Area 13500 0 0 0 0If (Line 8 >1.5, Line 6, Line 7/1.5] Sum of Landscape area [sum of Line 9 Id’s 1 to 5]13500 Provided footprint for evapotranspiration [Line 5 + Line 10]13756 Is Line 11 ≥Line 4?Volume Retention Performance Standard is Met Fraction of the performance standard met through the BMP footprint and/or landscaping [Line 11/Line 4]1.05 Target Volume Retention [Line 10 from Worksheet B.5.2]445 16 Sum of volume retention benefits from other site design BMPs (e.g. trees; rain barrels etc.). [sum of Line 16 Credits for Id’s 1 to 5] Provide documentation of how the site design credit is calculated in the PDP SWQMP. 0 Volume retention required from other site design BMPs [(1-Line 13) x Line 14]-22.25 Site Design BMP Site Design Type Credit Is Line 16 ≥ Line 15?Volume Retention Performance Standard is Met Project Name BMP ID 1 10288.57 sq. ft. 2 0.72 3 0.53 inches 4 329 cu. ft. 5 0 in/hr. 6 2 7 0 in/hr. 10 8 cu. ft. Area draining to the BMP Otay Town Center BF-2 Sizing Method for Volume Retention Worksheet B.5-2 %When Line 7 > 0.01 in/hr. = Minimum (40, 166.9 x Line 7 +6.62) When Line 7 ≤ 0.01 in/hr. = 3.5% Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) 85th percentile 24-hour rainfall depth Design capture volume [Line 1 x Line 2 x (Line 3/12)] Volume Retention Requirement Measured infiltration rate in the DMA Note: When mapped hydrologic soil groups are used enter 0.10 for NRCS Type D soils and for NRCS Type C soils enter 0.30 When in no infiltration condition and the actual measured infiltration rate is unknown enter 0.0 if there are geotechnical and/or groundwater hazards identified in Appendix C or enter 0.05 Factor of safety Reliable infiltration rate, for biofiltration BMP sizing [Line 5 / Line 6] 8 Average annual volume reduction target (Figure B.5-2) 3.5 Target volume retention [Line 9 x Line 4] 9 Fraction of DCV to be retained (Figure B.5-3) 0.023 When Line 8 > 8% = 0.0000013 x Line 83 - 0.000057 x Line 82 + 0.0086 x Line 8 - 0.014 When Line 8 ≤ 8% = 0.023 Project Name BMP ID 1 sq. ft. 2 3 sq. ft. 4 sq. ft. 5 sq. ft. Identification 1 4 5 6 7 10 sq. ft. 11 sq. ft. 12 13 14 cu. ft. 15 cu. ft. Identification 1 cu. ft. 2 cu. ft. 3 cu. ft. 4 cu. ft. 5 cu. ft. cu. ft. 17 Area draining to the biofiltration BMP 10288.57 Otay Town Center BF-2 Volume Retention for No Infiltration Condition Worksheet B.5-6 Landscape area that meet the requirements in SD-B and SD-F Fact Sheet (sq. ft.) Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)0.72 Effective impervious area draining to the BMP [Line 1 x Line 2]7453 Required area for Evapotranspiration [Line 3 x 0.03]224 Biofiltration BMP Footprint 16 Landscape Area (must be identified on DS-3247) 2 3 Impervious area draining to the landscape area (sq. ft.) 8 Impervious to Pervious Area ratio 0.00 0.00 0.00 Volume Retention Performance Standard 0.00 0.00[Line 7/Line 6] 9 Effective Credit Area 0 0 0 0 0If (Line 8 >1.5, Line 6, Line 7/1.5] Sum of Landscape area [sum of Line 9 Id’s 1 to 5]0 Provided footprint for evapotranspiration [Line 5 + Line 10]16 Is Line 11 ≥Line 4?No, Proceed to Line 13 Fraction of the performance standard met through the BMP footprint and/or landscaping [Line 11/Line 4]0.07 Target Volume Retention [Line 10 from Worksheet B.5.2]8 16 Credits from DMA-1 7.5 Sum of volume retention benefits from other site design BMPs (e.g. trees; rain barrels etc.). [sum of Line 16 Credits for Id’s 1 to 5] Provide documentation of how the site design credit is calculated in the PDP SWQMP. 7.5 Volume retention required from other site design BMPs [(1-Line 13) x Line 14]7.04 Site Design BMP Site Design Type Credit Is Line 16 ≥ Line 15?Volume Retention Performance Standard is Met Project Name BMP ID 1 5305.59 sq. ft. 2 0.73 3 0.53 inches 4 172 cu. ft. 5 0 in/hr. 6 2 7 0 in/hr. 10 4 cu. ft. Area draining to the BMP Otay Town Center BF-3 Sizing Method for Volume Retention Worksheet B.5-2 %When Line 7 > 0.01 in/hr. = Minimum (40, 166.9 x Line 7 +6.62) When Line 7 ≤ 0.01 in/hr. = 3.5% Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) 85th percentile 24-hour rainfall depth Design capture volume [Line 1 x Line 2 x (Line 3/12)] Volume Retention Requirement Measured infiltration rate in the DMA Note: When mapped hydrologic soil groups are used enter 0.10 for NRCS Type D soils and for NRCS Type C soils enter 0.30 When in no infiltration condition and the actual measured infiltration rate is unknown enter 0.0 if there are geotechnical and/or groundwater hazards identified in Appendix C or enter 0.05 Factor of safety Reliable infiltration rate, for biofiltration BMP sizing [Line 5 / Line 6] 8 Average annual volume reduction target (Figure B.5-2) 3.5 Target volume retention [Line 9 x Line 4] 9 Fraction of DCV to be retained (Figure B.5-3) 0.023 When Line 8 > 8% = 0.0000013 x Line 83 - 0.000057 x Line 82 + 0.0086 x Line 8 - 0.014 When Line 8 ≤ 8% = 0.023 Project Name BMP ID 1 sq. ft. 2 3 sq. ft. 4 sq. ft. 5 sq. ft. Identification 1 4 5 6 7 10 sq. ft. 11 sq. ft. 12 13 14 cu. ft. 15 cu. ft. Identification 1 cu. ft. 2 cu. ft. 3 cu. ft. 4 cu. ft. 5 cu. ft. cu. ft. 17 Area draining to the biofiltration BMP 5305.59 Otay Town Center BF-3 Volume Retention for No Infiltration Condition Worksheet B.5-6 Landscape area that meet the requirements in SD-B and SD-F Fact Sheet (sq. ft.) Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2)0.73 Effective impervious area draining to the BMP [Line 1 x Line 2]3897 Required area for Evapotranspiration [Line 3 x 0.03]117 Biofiltration BMP Footprint 16 Landscape Area (must be identified on DS-3247) 2 3 Impervious area draining to the landscape area (sq. ft.) 8 Impervious to Pervious Area ratio 0.00 0.00 0.00 Volume Retention Performance Standard 0.00 0.00[Line 7/Line 6] 9 Effective Credit Area 0 0 0 0 0If (Line 8 >1.5, Line 6, Line 7/1.5] Sum of Landscape area [sum of Line 9 Id’s 1 to 5]0 Provided footprint for evapotranspiration [Line 5 + Line 10]16 Is Line 11 ≥Line 4?No, Proceed to Line 13 Fraction of the performance standard met through the BMP footprint and/or landscaping [Line 11/Line 4]0.14 Target Volume Retention [Line 10 from Worksheet B.5.2]4 16 Credits from DMA-1 3.5 Sum of volume retention benefits from other site design BMPs (e.g. trees; rain barrels etc.). [sum of Line 16 Credits for Id’s 1 to 5] Provide documentation of how the site design credit is calculated in the PDP SWQMP. 3.5 Volume retention required from other site design BMPs [(1-Line 13) x Line 14]3.40 Site Design BMP Site Design Type Credit Is Line 16 ≥ Line 15?Volume Retention Performance Standard is Met Flow-Based Proprietary Biofiltration Sizing Description Units Filterra Unit Filterra Unit Drainage Basin ID or Name unitless BF-3-2 BF-3-3 Location N/A DMA-2 DMA-3 Total Tributary Area ac 0.236 0.122 Total Tributary Area sq ft 10289 5306 Final Adjusted Runoff Factor unitless 0.72 0.73 85th Percentile Design Rainfall Intensity in/hr 0.2 0.2 WQ Flow Rate CFS 0.034 0.018 Flow Rate Safety Factor unitless 1.5 1.5 Design Flow Rate CFS 0.051 0.027 Final Design Flow Rate CFS 0.051 0.027 Modular Wetland Model unitless 4-4 4-4 Modular Wetland Treatment Flow Rate (each)CFS 0.065 0.065 Number of Units #1 1 Modular Wetland Treatment Flow Rate (Total)CFS 0.065 0.065 Is The BMP Adequately Sized?unitless Yes Yes OTAY TOWN CENTER Filterra Infiltration Rate = 175 (in/hr) Filterra Flow per Square Foot = 0.00405 (ft3/sec/ft2) Filterra Flow Rate, Q = 0.00405 ft3/sec x Filterra Surface Area Rational Method, Q = C x I x A San Diego Multiplier, M = 1.5 Site Flowrate, Q = (C x DI x DA x M x 43560) / (12 x3600) OR DA = (12 x 3600 x Q) / (C x 43560 x DI x M) where Q = Flow (ft3/sec) DA = Drainage Area (acres) DI = Design Intensity (in/hr) C =Runoff coefficient (dimensionless) M = Multiplier (dimensionless) DI C C C 0.2 0.95 0.85 0.50 Filterra 100%Commercial Residential L W Filterra Surface Area Flow Rate, Q Imperv. DA max DA max DA (ft) (ft) (ft2) (ft3/sec) (acres) (acres) (acres) 4 4 16 0.0648 0.226 0.252 0.429 6 4 24 0.0972 0.338 0.378 0.643 6.5 4 26 0.1053 0.367 0.410 0.696 8 4 32 0.1296 0.451 0.504 0.857 12 4 48 0.1944 0.677 0.756 1.286 6 6 36 0.1458 0.507 0.567 0.964 8 6 48 0.1944 0.677 0.756 1.286 10 6 60 0.2431 0.846 0.945 1.607 12 6 72 0.2917 1.015 1.134 1.928 13 7 91 0.3686 1.283 1.434 2.437 12 8 96 0.3889 1.353 1.512 2.571 14 8 112 0.4537 1.579 1.765 3.000 16 8 128 0.5185 1.804 2.017 3.428 18 8 144 0.5833 2.030 2.269 3.857 20 8 160 0.6481 2.255 2.521 4.285 22 8 176 0.7130 2.481 2.773 4.714 Available Filterra Box Sizes Filterra Sizing Spreadsheet Uniform Intensity Approach Storm Intensity = 0.20 in/hr San Diego Region 9/20/2019 CALCULATION SHEET FOR EVAPOTRANSPIRATION INSIDE THE MODULAR WETLAND SYSTEM LINEAR The Modular Wetland System Linear is a biofiltration system utilizing a highly porous bioretention media bed capable of maximizing pollutant removal and reducing volume through evapotranspiration. The media used in the system, known as WetlandMedia, is composed of a non-organic material mix which has a large percentage of interparticle and internal pore space: Porosity: Interparticle Void Percentage = 0.48 Internal Pore Space (inside particles) = 0.24 Total Void Space Percentage = 0.72 Benefits: Physically Inert Greater Surface Area & Porosity Excellent Hydraulic Conductivity Reduced Weight Employs Ion Exchange Absorbs High Levels of Moisture for Better Plant Propagation Lightweight Contains various oxides for removal of dissolved pollutants Calculating Evapotranspiration: Several studies have been performed to calculate the amount of evapotranspiration from the biofiltration system. It has been found that it is a function of the moisture holding capacity of the material and it’s relation to the “welting point”. Much of this work has been done by Geosyntec. In 2016, the City of San Diego released the new “Storm Water Standards Manual” and “Part 1: BMP Design Manual – Appendices”. The manual and appendices was prepared by Geosyntec Consultants and Michael Baker International. Page G-23 of the above referenced manual provides the following method of calculating the amount of evapotranspiration that can occur within the soil layer of biofiltration systems: This process layer is typically composed of an amended soil or compost mix. Water that infiltrates into this component is stored in the soil void space and is available for evapotranspiration via plant roots or can percolate into the storage layer below. The following parameters are used: Thickness: This parameter represents the depth of the amended soil layer. Porosity: Ratio of pore space volume to soil volume. Field Capacity: Pore water volume ratio after the soil has been drained. Wilting Point: Pore water volume ratio after the soil has been dried. Conductivity: This represents the saturated hydraulic conductivity. Conductivity Slope: Rate at which conductivity decreases with decreasing soil moisture content. Suction Head: This represents the capillary tension of water in the soil. Porosity, conductivity and suction head values as a function of soil texture were included in Table G.1-5. The flow of water through partially saturated soil is less than under fully saturated conditions. The SWMM program accounts for this reduced hydraulic conductivity to predict the rate at which infiltrated water moves through a layer of unsaturated soil when modeling groundwater or LID controls. The conductivity slope is a dimensionless curve-fitting parameter that relates the partially saturated hydraulic conductivity to the soil moisture content. The Modular Wetland System Linear has the following parameters related to evapotranspiration as described above: Thickness: 20” Porosity (interparticle + internal): 0.72 Field Capacity: 0.24 (50% of interparticle void space at 0.48 due to capillary tension + 100% of internal void space at 0.24 = (50% x 0.48) + (100% x 0.24)): 0.48 Welting Point: 0.1 (standard from Manual based on field research done by Geosyntec) Conductivity: > 395 in/hr The following diagram taken from the San Diego Manual illustrates soil saturation, field capacity and permanent wilting point: The following worksheet can be used to calculate the amount of volume reduction provided through the process of evapotranspiration in the Modular Wetland System Linear: Sizing Method of Evapotranspiration Losses in Biofiltration BMPs Project Name Model # Media Volume Calculations 1 Media bed width ft 2 Media bed length ft 3 Media bed height ft 4 Total media volume [Line 1 x 2 x 3] cu ft Evapotranspiration Calculations 5 Porosity 6 Field Capacity 7 Welting Point 8 Water Storage Capacity [Line 4 x Line 5] cu ft 9 Field Capacity - Welting Point [Line 6 - Line 7] 10 Total Evapotranspiration [ Line 4 x Line 9] cu ft This worksheet and supporting data can be used and can be included in your technical report. If you have any questions please call us at 760-433-7640 or email us at info@modularwetlands.com 398 Via El Centro, Oceanside, CA 92058 Phone 760 433-7640 • Fax 760-433-3176 www.biocleanenvironmental.com Date: 02-13-23 Project: 722608 - Otay Town Center To Whom It May Concern, The MWS Linear will be sized in accordance with its TAPE GULD approval. The system is approved at a loading rate less than or equal to 1 gpm/sq ft or 100 inches per hour. The MWS Linear has General Use Level Designation at this loading rate for TSS (Basic), phosphorous and dissolved metals (Enhanced). For this project design, sizing, loading will be reviewed by a Modular Wetland representative for final approval to ensure the system is sized appropriately. For this project we are utilizing a custom MWS sized volume based system. Due to the volume sizing we are using a safety factor on our media loading rate and only sizing at a loading rate of 0.26 gpm/sf. Using a safety factor will greatly prolong the life of the WetlandMEDIA and decrease the long term maintenance costs. BF-3-1 – Two MWS0816 units Wetland Perimeter Length = 59.20’ Treatment HGL = 3.3’ Media Surface Area Provided = 195.36 sf (Combined Surface Area Provided = 390.72 sf) Average Discharge Rate = 50.79 gpm WetlandMEDIA Loading Rate = 0.26 gpm/sf or 26 inches per hour If you have any comments or questions please feel free to contact us at your convenience. Sincerely, Mason Noble Stormwater Engineer 1 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Compact (high rate) biofiltration BMPs have a media filtration rate greater than 5 in/hr. and a media surface area smaller than 3% of contributing area times adjusted runoff factor. Compact biofiltration BMPs are typically proprietary BMPs that may qualify as biofiltration. A compact biofiltration BMP may satisfy the pollutant control requirements for a DMA onsite in some cases. This depends on the characteristics of the DMA and the performance certification/data of the BMP. If the pollutant control requirements for a DMA are met onsite, then the DMA is not required to participate in an offsite storm water alternative compliance program to meet its pollutant control obligations. An applicant using a compact biofiltration BMP to meet the pollutant control requirements onsite must complete Section 1 of this form and include it in the PDP SWQMP. A separate form must be completed for each DMA. In instances where the City Engineer does not agree with the applicant’s determination, Section 2 of this form will be completed by the City and returned to the applicant. Section 1: Biofiltration Criteria Checklist (Appendix F) Refer to Part 1 of the Storm Water Standards to complete this section. When separate forms/worksheets are referenced below, the applicant must also complete these separate forms/worksheets (as applicable) and include in the PDP SWQMP. The criteria numbers below correspond to the criteria numbers in Appendix F. Criteria Answer Progression Criteria 1 and 3: What is the infiltration condition of the DMA? Refer to Section 5.4.2 and Appendix C of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Applicant must complete and include the following in the PDP SWQMP submittal to support the feasibility determination: •Infiltration Feasibility Condition Letter; or •Worksheet C.4-1: Form I-8A and Worksheet C.4-2: Form I- 8B. Applicant must complete and include all applicable sizing worksheets in the SWQMP submittal Full Infiltration Condition Stop. Compact biofiltration BMP is not allowed. Partial Infiltration Condition Compact biofiltration BMP is only allowed, if the target volume retention is met onsite (Refer to Table B.5-1 in Appendix B.5). Use Worksheet B.5- 2 in Appendix B.5 to estimate the target volume retention (Note: retention in this context means reduction). If the required volume reduction is achieved proceed to Criteria 2. If the required volume reduction is not achieved, compact biofiltration BMP is not allowed. Stop. No Infiltration Condition Compact biofiltration BMP is allowed if volume retention criteria in Table B.5-1 in Appendix B.5 for the no infiltration condition is met. Compliance with this criterion must be documented in the PDP SWQMP. If the criteria in Table B.5-1 is met proceed to Criteria 2. If the criteria in Table B.5-1 is not met, compact biofiltration BMP is not allowed. Stop. 2 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Provide basis for Criteria 1 and 3: Feasibility Analysis: Summarize findings and include either infiltration feasibility condition letter or Worksheet C.4-1: Form I-8A and Worksheet C.4-2: Form I-8B in the PDP SWQMP submittal. If Partial Infiltration Condition: Provide documentation that target volume retention is met (include Worksheet B.5-2 in the PDP SWQMP submittal). Worksheet B.5-7 in Appendix B.5 can be used to estimate volume retention benefits from landscape areas. If No Infiltration Condition: Provide documentation that the volume retention performance standard is met (include Worksheet B.5-2 in the PDP SWQMP submittal) in the PDP SWQMP submittal. Worksheet B.5-6 in Appendix B.5 can be used to document that the performance standard is met. Criteria Answer Progression Criteria 2: Is the compact biofiltration BMP sized to meet the performance standard from the MS4 Permit? Refer to Appendix B.5 and Appendix F.2 of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Meets Flow based Criteria Use guidance from Appendix F.2.2 to size the compact biofiltration BMP to meet the flow based criteria. Include the calculations in the PDP SWQMP. Use parameters for sizing consistent with manufacturer guidelines and conditions of its third party certifications (i.e. a BMP certified at a loading rate of 1 gpm/sq. ft. cannot be designed using a loading rate of 1.5 gpm/sq. ft.) Proceed to Criteria 4. Meets Volume based Criteria Provide documentation that the compact biofiltration BMP has a total static (i.e. non- routed) storage volume, including pore-spaces and pre-filter detention volume (Refer to Appendix B.5 for a schematic) of at least 0.75 times the portion of the DCV not reliably retained onsite. Proceed to Criteria 4. Does not Meet either criteria Stop. Compact biofiltration BMP is not allowed. 3 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Provide basis for Criteria 2: Provide documentation that the BMP meets the numeric criteria and is designed consistent with the manufacturer guidelines and conditions of its third-party certification (i.e., loading rate, etc., as applicable). Criteria Answer Progression Criteria 4: Does the compact biofiltration BMP meet the pollutant treatment performance standard for the projects most significant pollutants of concern? Refer to Appendix B.6 and Appendix F.1 of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Yes, meets the TAPE certification. Provide documentation that the compact BMP has an appropriate TAPE certification for the projects most significant pollutants of concern. Proceed to Criteria 5. Yes, through other third-party documentation Acceptance of third-party documentation is at the discretion of the City Engineer. The City engineer will consider, (a) the data submitted; (b) representativeness of the data submitted; and (c) consistency of the BMP performance claims with pollutant control objectives in Table F.1-2 and Table F.1-1 while making this determination. If a compact biofiltration BMP is not accepted, a written explanation/ reason will be provided in Section 2. Proceed to Criteria 5. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 4: Provide documentation that identifies the projects most significant pollutants of concern and TAPE certification or other third party documentation that shows that the compact biofiltration BMP meets the pollutant treatment performance standard for the projects most significant pollutants of concern. 4 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Criteria Answer Progression Criteria 5: Is the compact biofiltration BMP designed to promote appropriate biological activity to support and maintain treatment process? Refer to Appendix F of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Yes Provide documentation that the compact biofiltration BMP support appropriate biological activity. Refer to Appendix F for guidance. Proceed to Criteria 6. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 5: Provide documentation that appropriate biological activity is supported by the compact biofiltration BMP to maintain treatment process. Criteria Answer Progression Criteria 6: Is the compact biofiltration BMP designed with a hydraulic loading rate to prevent erosion, scour and channeling within the BMP? Yes Provide documentation that the compact biofiltration BMP is used in a manner consistent with manufacturer guidelines and conditions of its third-party certification. Proceed to Criteria 7. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 6: Provide documentation that the BMP meets the numeric criteria and is designed consistent with the manufacturer guidelines and conditions of its third-party certification (i.e., maximum tributary area, maximum inflow velocities, etc., as applicable). 5 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Criteria Answer Progression Criteria 7: Is the compact biofiltration BMP maintenance plan consistent with manufacturer guidelines and conditions of its third-party certification (i.e., maintenance activities, frequencies)? Yes, and the compact BMP is privately owned, operated and not in the public right of way. Submit a maintenance agreement that will also include a statement that the BMP will be maintained in accordance with manufacturer guidelines and conditions of third-party certification. Stop. The compact biofiltration BMP meets the required criteria. Yes, and the BMP is either owned or operated by the City or in the public right of way. Approval is at the discretion of the City Engineer. The city engineer will consider maintenance requirements, cost of maintenance activities, relevant previous local experience with operation and maintenance of the BMP type, ability to continue to operate the system in event that the vending company is no longer operating as a business or other relevant factors while making the determination. Stop. Consult the City Engineer for a determination. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 7: Include copy of manufacturer guidelines and conditions of third-party certification in the maintenance agreement. PDP SWQMP must include a statement that the compact BMP will be maintained in accordance with manufacturer guidelines and conditions of third-party certification. 6 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Section 2: Verification (For City Use Only) Is the proposed compact BMP accepted by the City Engineer for onsite pollutant control compliance for the DMA? Yes No, See explanation below Explanation/reason if the compact BMP is not accepted by the City for onsite pollutant control compliance: 1 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Compact (high rate) biofiltration BMPs have a media filtration rate greater than 5 in/hr. and a media surface area smaller than 3% of contributing area times adjusted runoff factor. Compact biofiltration BMPs are typically proprietary BMPs that may qualify as biofiltration. A compact biofiltration BMP may satisfy the pollutant control requirements for a DMA onsite in some cases. This depends on the characteristics of the DMA and the performance certification/data of the BMP. If the pollutant control requirements for a DMA are met onsite, then the DMA is not required to participate in an offsite storm water alternative compliance program to meet its pollutant control obligations. An applicant using a compact biofiltration BMP to meet the pollutant control requirements onsite must complete Section 1 of this form and include it in the PDP SWQMP. A separate form must be completed for each DMA. In instances where the City Engineer does not agree with the applicant’s determination, Section 2 of this form will be completed by the City and returned to the applicant. Section 1: Biofiltration Criteria Checklist (Appendix F) Refer to Part 1 of the Storm Water Standards to complete this section. When separate forms/worksheets are referenced below, the applicant must also complete these separate forms/worksheets (as applicable) and include in the PDP SWQMP. The criteria numbers below correspond to the criteria numbers in Appendix F. Criteria Answer Progression Criteria 1 and 3: What is the infiltration condition of the DMA? Refer to Section 5.4.2 and Appendix C of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Applicant must complete and include the following in the PDP SWQMP submittal to support the feasibility determination: •Infiltration Feasibility Condition Letter; or •Worksheet C.4-1: Form I-8A and Worksheet C.4-2: Form I- 8B. Applicant must complete and include all applicable sizing worksheets in the SWQMP submittal Full Infiltration Condition Stop. Compact biofiltration BMP is not allowed. Partial Infiltration Condition Compact biofiltration BMP is only allowed, if the target volume retention is met onsite (Refer to Table B.5-1 in Appendix B.5). Use Worksheet B.5- 2 in Appendix B.5 to estimate the target volume retention (Note: retention in this context means reduction). If the required volume reduction is achieved proceed to Criteria 2. If the required volume reduction is not achieved, compact biofiltration BMP is not allowed. Stop. No Infiltration Condition Compact biofiltration BMP is allowed if volume retention criteria in Table B.5-1 in Appendix B.5 for the no infiltration condition is met. Compliance with this criterion must be documented in the PDP SWQMP. If the criteria in Table B.5-1 is met proceed to Criteria 2. If the criteria in Table B.5-1 is not met, compact biofiltration BMP is not allowed. Stop. 2 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Provide basis for Criteria 1 and 3: Feasibility Analysis: Summarize findings and include either infiltration feasibility condition letter or Worksheet C.4-1: Form I-8A and Worksheet C.4-2: Form I-8B in the PDP SWQMP submittal. If Partial Infiltration Condition: Provide documentation that target volume retention is met (include Worksheet B.5-2 in the PDP SWQMP submittal). Worksheet B.5-7 in Appendix B.5 can be used to estimate volume retention benefits from landscape areas. If No Infiltration Condition: Provide documentation that the volume retention performance standard is met (include Worksheet B.5-2 in the PDP SWQMP submittal) in the PDP SWQMP submittal. Worksheet B.5-6 in Appendix B.5 can be used to document that the performance standard is met. Criteria Answer Progression Criteria 2: Is the compact biofiltration BMP sized to meet the performance standard from the MS4 Permit? Refer to Appendix B.5 and Appendix F.2 of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Meets Flow based Criteria Use guidance from Appendix F.2.2 to size the compact biofiltration BMP to meet the flow based criteria. Include the calculations in the PDP SWQMP. Use parameters for sizing consistent with manufacturer guidelines and conditions of its third party certifications (i.e. a BMP certified at a loading rate of 1 gpm/sq. ft. cannot be designed using a loading rate of 1.5 gpm/sq. ft.) Proceed to Criteria 4. Meets Volume based Criteria Provide documentation that the compact biofiltration BMP has a total static (i.e. non- routed) storage volume, including pore-spaces and pre-filter detention volume (Refer to Appendix B.5 for a schematic) of at least 0.75 times the portion of the DCV not reliably retained onsite. Proceed to Criteria 4. Does not Meet either criteria Stop. Compact biofiltration BMP is not allowed. 3 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Provide basis for Criteria 2: Provide documentation that the BMP meets the numeric criteria and is designed consistent with the manufacturer guidelines and conditions of its third-party certification (i.e., loading rate, etc., as applicable). Criteria Answer Progression Criteria 4: Does the compact biofiltration BMP meet the pollutant treatment performance standard for the projects most significant pollutants of concern? Refer to Appendix B.6 and Appendix F.1 of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Yes, meets the TAPE certification. Provide documentation that the compact BMP has an appropriate TAPE certification for the projects most significant pollutants of concern. Proceed to Criteria 5. Yes, through other third-party documentation Acceptance of third-party documentation is at the discretion of the City Engineer. The City engineer will consider, (a) the data submitted; (b) representativeness of the data submitted; and (c) consistency of the BMP performance claims with pollutant control objectives in Table F.1-2 and Table F.1-1 while making this determination. If a compact biofiltration BMP is not accepted, a written explanation/ reason will be provided in Section 2. Proceed to Criteria 5. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 4: Provide documentation that identifies the projects most significant pollutants of concern and TAPE certification or other third party documentation that shows that the compact biofiltration BMP meets the pollutant treatment performance standard for the projects most significant pollutants of concern. 4 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Criteria Answer Progression Criteria 5: Is the compact biofiltration BMP designed to promote appropriate biological activity to support and maintain treatment process? Refer to Appendix F of the BMP Design Manual (Part 1 of Storm Water Standards) for guidance. Yes Provide documentation that the compact biofiltration BMP support appropriate biological activity. Refer to Appendix F for guidance. Proceed to Criteria 6. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 5: Provide documentation that appropriate biological activity is supported by the compact biofiltration BMP to maintain treatment process. Criteria Answer Progression Criteria 6: Is the compact biofiltration BMP designed with a hydraulic loading rate to prevent erosion, scour and channeling within the BMP? Yes Provide documentation that the compact biofiltration BMP is used in a manner consistent with manufacturer guidelines and conditions of its third-party certification. Proceed to Criteria 7. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 6: Provide documentation that the BMP meets the numeric criteria and is designed consistent with the manufacturer guidelines and conditions of its third-party certification (i.e., maximum tributary area, maximum inflow velocities, etc., as applicable). 5 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Criteria Answer Progression Criteria 7: Is the compact biofiltration BMP maintenance plan consistent with manufacturer guidelines and conditions of its third-party certification (i.e., maintenance activities, frequencies)? Yes, and the compact BMP is privately owned, operated and not in the public right of way. Submit a maintenance agreement that will also include a statement that the BMP will be maintained in accordance with manufacturer guidelines and conditions of third-party certification. Stop. The compact biofiltration BMP meets the required criteria. Yes, and the BMP is either owned or operated by the City or in the public right of way. Approval is at the discretion of the City Engineer. The city engineer will consider maintenance requirements, cost of maintenance activities, relevant previous local experience with operation and maintenance of the BMP type, ability to continue to operate the system in event that the vending company is no longer operating as a business or other relevant factors while making the determination. Stop. Consult the City Engineer for a determination. No Stop. Compact biofiltration BMP is not allowed. Provide basis for Criteria 7: Include copy of manufacturer guidelines and conditions of third-party certification in the maintenance agreement. PDP SWQMP must include a statement that the compact BMP will be maintained in accordance with manufacturer guidelines and conditions of third-party certification. 6 The City of San Diego | Storm Water Standards Form I-10 | January 2018 Edition Compact (high rate) Biofiltration BMP Checklist Form I-10 Section 2: Verification (For City Use Only) Is the proposed compact BMP accepted by the City Engineer for onsite pollutant control compliance for the DMA? Yes No, See explanation below Explanation/reason if the compact BMP is not accepted by the City for onsite pollutant control compliance: Otay Ranch Town Center Otay Ranch Town Center Otay Ranch Town Center Otay Ranch Town Center ATTACHMENT 2a HYDROMODIFICATION MANAGEMENT EXHIBITS STORAGE FACILITY HMP -1 16800 SF x 5.5 FT NORTH AVE. T O W N C E N T E R D R . ( N O R T H B O U N D ) T O W N C E N T E R D R . ( S O U T H B O U N D ) DMA 2 BF-3-3 FILTERRA DMA 1 BF-3-1 MWS 2N D S T R E E T BF-3-2 DMA 3 FILTERRA LOT 1 LOT AREA:1.50 AC. PAD AREA:1.45 AC. LOT W LOT AREA:0.74 AC. PAD AREA: 0.71 AC. NORTH AVE. T O W N C E N T E R D R . ( N O R T H B O U N D ) T O W N C E N T E R D R . ( S O U T H B O U N D ) 2N D S T R E E T LOT 2 LOT AREA:1.18 AC. PAD AREA:1.10 AC. LOT 3 LOT AREA:1.81 AC. PAD AREA:1.71 AC. LOT 4 LOT AREA:1.81 AC. PAD AREA:1.63 AC. LOT 9 LOT AREA:0.47 AC. PAD AREA:0.42 AC. LOT 6 LOT AREA:0.73 AC. PAD AREA:0.69 AC. LOT 8 LOT AREA:1.17 AC. PAD AREA:1.13 AC. LOT 7 LOT AREA:1.19 AC. PAD AREA:1.14 AC. LOT 5 LOT AREA:0.73 AC. PAD AREA:0.69 AC. BIRCH ROAD LOT G LOT AREA:0.38 AC. PAD AREA:0.36 AC. LOT F LOT AREA:0.87 AC. PAD AREA:0.70 AC. OTAY TOWN CENTER HUNSAKER& ASSOCIATES PREPARED BY: CITY CHULA VISTA, CALIFORNIA OF 2 1HMP MAP LEGEND: PROJECT BOUNDARY........................................................................................... DMA BOUNDARY.................................................................................................... DAYLIGHT............................................................................................................... PROPOSED STORM DRAIN.................................................................................. EXISTING STORM DRAIN...................................................................................... FLOW LINE............................................................................................................. SUBAREA ACREAGE............................................................................................. DMA ICON............................................................................................................... IMPERVIOUS - ROAD............................................................................................ IMPERVIOUS - SIDEWALK.................................................................................... PERVIOUS AREAS................................................................................................. LOTS 1 AND 2......................................................................................................... LOTS 3 AND 4......................................................................................................... LOTS 5, 6, 7, AND 8................................................................................................ LOT 9....................................................................................................................... UNDERGROUND STORAGE FACILITY................................................................. MWS UNIT.............................................................................................................. TRENCHING & RESURFACING............................................................................ EX. IMPREVIOUSNESS DRAINING TO BMPS.................................................... INLET...................................................................................................................... HYDROLOGIC SOIL TYPE..................................................................................... POINT OF COMPLIANCE....................................................................................... STRUCTURAL BMP\ MWS UNIT............................................................................ SYMBOL: DMA 1 POC BELOW IS AROUND OF THE PROJECT900' SOUTH SEE RIGHT FOR LOT G AND F SEE LEFT FOR LOT 10 LOT 10 LOT 1 LOT 5 LOT 7 LOT 8 LOT 6 LOT 9 LOT 2 LOT 3 LOT 4 LOT A LOT B LOT C LOT D LOT I LOT H LOT E LOT 10 LOT F LOT G OTAY TOWN CENTER HUNSAKER& ASSOCIATES PREPARED BY: CITY CHULA VISTA, CALIFORNIA OF 2 2EXISTING HMP MAP PROJECT BOUNDARY PROPOSED DMA BOUNDARY DAYLIGHT FLOW DIRECTION AREA HYDROLOGIC SOIL TYPE EXISTING IMPERVIOUS AREA EXISITNG STORM DRAIN LEGEND DMA 1 EXISTING IMPERVIOUS AREA = 10.3 AC ATTACHMENT 2b MANAGEMENT OF CRITICAL COARSE SEDIMENT YIELD AREAS PCCSYA O TAY TO W N CENTER Legend PCCSYA 1 mi N ➤➤ N © 2020 Google © 2020 Google © 2020 Google © 2020 INEGI © 2020 INEGI © 2020 INEGI ATTACHMENT 2c GEOMORPHIC ASSESSMENT OF RECEIVING CHANNELS ATTACHMENT 2d FLOW CONTROL FACILITY DESIGN Project Name:Otay Ranch Town Center Project Applicant:Brookfield Jurisdiction:City of Chula Vista Parcel (APN):Enter Parcel Number(s) Hydrologic Unit:Otay Rain Gauge:Lindbergh Total Project Area (sf):645,559 Channel Susceptibility:High BMP Sizing Spreadsheet V3.1 Project Name:Hydrologic Unit: Project Applicant:Rain Gauge: Jurisdiction:Total Project Area: Parcel (APN):Low Flow Threshold: BMP Name:BMP Type: BMP Native Soil Type:BMP Infiltration Rate (in/hr): HMP Sizing Factors Minimum BMP Size DMA Name Area (sf) Pre Project Soil Type Pre-Project Slope Post Project Surface Type Area Weighted Runoff Factor (Table G.2-1)1 Volume Volume (CF) Impervious 466,909 D Flat Roofs 1.00 0.09 42022 Landscaped 178,651 D Flat Landscape 0.1 0.09 1608 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 BMP Tributary Area 645,560 Minimum BMP Size 43630 Proposed BMP Size** Assumes standard configuration 3.5 ft 3.5 ft 12466 CF Notes: 1. Runoff factors which are used for hydromodification management flow control (Table G.2-1) are different from the runoff factors used for pollutant control BMP sizing (Table B.1-1). Table references are taken from the San Diego Region Model BMP Design Manual, May 2018. This BMP Sizing Spreadsheet has been updated in conformance with the San Diego Region Model BMP Design Manual, May 2018. For questions or concerns please contact the jurisdiction in which your project is located. Describe the BMP's in sufficient detail in your PDP SWQMP to demonstrate the area, volume, and other criteria can be met within the constraints of the site. BMP's must be adapted and applied to the conditions specific to the development project such as unstable slopes or the lack of available head. Designated Staff have final review and approval authority over the project design. Standard Cistern Depth (Overflow Elevation) Provided Cistern Depth (Overflow Elevation) Minimum Required Cistern Footprint) Areas Draining to BMP City of Chula Vista Enter Parcel Number(s) C BMP Sizing Spreadsheet V3.1 NA Cistern 0.1Q2 645,559 Lindbergh Otay HMP-1 Otay Ranch Town Center Brookfield Project Name:Hydrologic Unit: Project Applicant:Rain Gauge: Jurisdiction:Total Project Area: Parcel (APN):Low Flow Threshold: BMP Name BMP Type: Rain Gauge Unit Runoff Ratio DMA Area (ac)Orifice Flow - %Q2 Orifice Area Soil Type Slope (cfs/ac)(cfs) (in2) Impervious Lindbergh D Flat 0.429 10.719 0.460 6.79 Landscaped Lindbergh D Flat 0.429 4.101 0.176 2.60 3.50 0.636 9.38 3.46 Max Orifice Head Max Tot. Allowable Orifice Flow Max Tot. Allowable Orifice Area Max Orifice Diameter (feet)(cfs)(in2)(in) Provide Hand Calc.0.652 9.62 3.500 Average outflow during surface drawdown Max Orifice Outflow Actual Orifice Area Selected Orifice Diameter (cfs)(cfs)(in2)(in) Drawdown (Hrs)Provide Hand Calculation HMP-1 Pre-developed Condition No Orifice Required for Infiltration Facilities DMA Name Otay BMP Sizing Spreadsheet V3.1 City of Chula Vista Enter Parcel Number(s) Otay Ranch Town Center Brookfield 0.1Q2 645,559 Lindbergh Cistern Drawdown time exceeds 96 Hrs. Project must implement a vector control program. Lower Flow Threshold Soil Group Slope Rain Gauge A 0.1Q2 A Flat Lindbergh 0.055 0.1Q2 A Moderate Lindbergh 0.055 0.1Q2 A Steep Lindbergh 0.055 0.1Q2 B Flat Lindbergh 0.045 0.1Q2 B Moderate Lindbergh 0.045 0.1Q2 B Steep Lindbergh 0.045 0.1Q2 C Flat Lindbergh 0.035 0.1Q2 C Moderate Lindbergh 0.035 0.1Q2 C Steep Lindbergh 0.035 0.1Q2 D Flat Lindbergh 0.03 0.1Q2 D Moderate Lindbergh 0.03 0.1Q2 D Steep Lindbergh 0.03 0.1Q2 A Flat Oceanside 0.06 0.1Q2 A Moderate Oceanside 0.06 0.1Q2 A Steep Oceanside 0.06 0.1Q2 B Flat Oceanside 0.05 0.1Q2 B Moderate Oceanside 0.05 0.1Q2 B Steep Oceanside 0.05 0.1Q2 C Flat Oceanside 0.05 0.1Q2 C Moderate Oceanside 0.05 0.1Q2 C Steep Oceanside 0.045 0.1Q2 D Flat Oceanside 0.035 0.1Q2 D Moderate Oceanside 0.035 0.1Q2 D Steep Oceanside 0.035 0.1Q2 A Flat Lake Wohlford 0.085 0.1Q2 A Moderate Lake Wohlford 0.085 0.1Q2 A Steep Lake Wohlford 0.085 0.1Q2 B Flat Lake Wohlford 0.07 Table G.2-3: Sizing Factors for Hydromodification Flow Control Infiltration BMPs Designed Using Sizing Factor Method 0.1Q2 B Moderate Lake Wohlford 0.07 0.1Q2 B Steep Lake Wohlford 0.07 0.1Q2 C Flat Lake Wohlford 0.055 0.1Q2 C Moderate Lake Wohlford 0.055 0.1Q2 C Steep Lake Wohlford 0.055 0.1Q2 D Flat Lake Wohlford 0.04 0.1Q2 D Moderate Lake Wohlford 0.04 0.1Q2 D Steep Lake Wohlford 0.04 Lower Flow Threshold Soil Group SlopeAggregate below low orifice invert (inches)Rain Gauge A 0.1Q2 A Flat 18 Lindbergh 0.08 0.1Q2 A Moderate 18 Lindbergh 0.08 0.1Q2 A Steep 18 Lindbergh 0.08 0.1Q2 B Flat 18 Lindbergh 0.065 0.1Q2 B Moderate 18 Lindbergh 0.065 0.1Q2 B Steep 18 Lindbergh 0.06 0.1Q2 C Flat 6 Lindbergh 0.05 0.1Q2 C Moderate 6 Lindbergh 0.05 0.1Q2 C Steep 6 Lindbergh 0.05 0.1Q2 D Flat 3 Lindbergh 0.05 0.1Q2 D Moderate 3 Lindbergh 0.05 0.1Q2 D Steep 3 Lindbergh 0.05 0.1Q2 A Flat 18 Oceanside 0.08 0.1Q2 A Moderate 18 Oceanside 0.075 0.1Q2 A Steep 18 Oceanside 0.075 0.1Q2 B Flat 18 Oceanside 0.07 0.1Q2 B Moderate 18 Oceanside 0.07 0.1Q2 B Steep 18 Oceanside 0.07 Table G.2-4: Sizing Factors for Hydromodification Flow Control Biofiltration with Partial Retention Designed Using Sizing Factor Method 0.1Q2 C Flat 6 Oceanside 0.07 0.1Q2 C Moderate 6 Oceanside 0.07 0.1Q2 C Steep 6 Oceanside 0.07 0.1Q2 D Flat 3 Oceanside 0.07 0.1Q2 D Moderate 3 Oceanside 0.07 0.1Q2 D Steep 3 Oceanside 0.07 0.1Q2 A Flat 18 Lake Wohlford 0.11 0.1Q2 A Moderate 18 Lake Wohlford 0.11 0.1Q2 A Steep 18 Lake Wohlford 0.105 0.1Q2 B Flat 18 Lake Wohlford 0.09 0.1Q2 B Moderate 18 Lake Wohlford 0.085 0.1Q2 B Steep 18 Lake Wohlford 0.085 0.1Q2 C Flat 6 Lake Wohlford 0.065 0.1Q2 C Moderate 6 Lake Wohlford 0.065 0.1Q2 C Steep 6 Lake Wohlford 0.065 0.1Q2 D Flat 3 Lake Wohlford 0.06 0.1Q2 D Moderate 3 Lake Wohlford 0.06 0.1Q2 D Steep 3 Lake Wohlford 0.06 Lower Flow Threshold Soil Group Slope Rain Gauge A 0.1Q2 A Flat Lindbergh 0.32 0.1Q2 A Moderate Lindbergh 0.3 0.1Q2 A Steep Lindbergh 0.285 0.1Q2 B Flat Lindbergh 0.105 0.1Q2 B Moderate Lindbergh 0.1 0.1Q2 B Steep Lindbergh 0.095 0.1Q2 C Flat Lindbergh 0.055 0.1Q2 C Moderate Lindbergh 0.05 0.1Q2 C Steep Lindbergh 0.05 0.1Q2 D Flat Lindbergh 0.05 0.1Q2 D Moderate Lindbergh 0.05 Table G.2-5: Sizing Factors for Hydromodification Flow Control Biofiltration BMPs Designed Using Sizing Factor Method 0.1Q2 D Steep Lindbergh 0.05 0.1Q2 A Flat Oceanside 0.15 0.1Q2 A Moderate Oceanside 0.14 0.1Q2 A Steep Oceanside 0.135 0.1Q2 B Flat Oceanside 0.085 0.1Q2 B Moderate Oceanside 0.085 0.1Q2 B Steep Oceanside 0.085 0.1Q2 C Flat Oceanside 0.075 0.1Q2 C Moderate Oceanside 0.075 0.1Q2 C Steep Oceanside 0.075 0.1Q2 D Flat Oceanside 0.07 0.1Q2 D Moderate Oceanside 0.07 0.1Q2 D Steep Oceanside 0.07 0.1Q2 A Flat Lake Wohlford 0.285 0.1Q2 A Moderate Lake Wohlford 0.275 0.1Q2 A Steep Lake Wohlford 0.27 0.1Q2 B Flat Lake Wohlford 0.15 0.1Q2 B Moderate Lake Wohlford 0.145 0.1Q2 B Steep Lake Wohlford 0.145 0.1Q2 C Flat Lake Wohlford 0.07 0.1Q2 C Moderate Lake Wohlford 0.07 0.1Q2 C Steep Lake Wohlford 0.07 0.1Q2 D Flat Lake Wohlford 0.06 0.1Q2 D Moderate Lake Wohlford 0.06 0.1Q2 D Steep Lake Wohlford 0.06 Lower Flow Threshold Soil Group Slope Rain Gauge V 0.1Q2 A Flat Lindbergh 0.54 0.1Q2 A Moderate Lindbergh 0.51 0.1Q2 A Steep Lindbergh 0.49 0.1Q2 B Flat Lindbergh 0.19 Table G.2-6: Sizing Factors for Hydromodification Flow Control Cistern Facilities Designed Using Sizing Factor Method 0.1Q2 B Moderate Lindbergh 0.18 0.1Q2 B Steep Lindbergh 0.18 0.1Q2 C Flat Lindbergh 0.11 0.1Q2 C Moderate Lindbergh 0.11 0.1Q2 C Steep Lindbergh 0.11 0.1Q2 D Flat Lindbergh 0.09 0.1Q2 D Moderate Lindbergh 0.09 0.1Q2 D Steep Lindbergh 0.09 0.1Q2 A Flat Oceanside 0.26 0.1Q2 A Moderate Oceanside 0.25 0.1Q2 A Steep Oceanside 0.25 0.1Q2 B Flat Oceanside 0.16 0.1Q2 B Moderate Oceanside 0.16 0.1Q2 B Steep Oceanside 0.16 0.1Q2 C Flat Oceanside 0.14 0.1Q2 C Moderate Oceanside 0.14 0.1Q2 C Steep Oceanside 0.14 0.1Q2 D Flat Oceanside 0.12 0.1Q2 D Moderate Oceanside 0.12 0.1Q2 D Steep Oceanside 0.12 0.1Q2 A Flat Lake Wohlford 0.53 0.1Q2 A Moderate Lake Wohlford 0.49 0.1Q2 A Steep Lake Wohlford 0.49 0.1Q2 B Flat Lake Wohlford 0.28 0.1Q2 B Moderate Lake Wohlford 0.28 0.1Q2 B Steep Lake Wohlford 0.28 0.1Q2 C Flat Lake Wohlford 0.14 0.1Q2 C Moderate Lake Wohlford 0.14 0.1Q2 C Steep Lake Wohlford 0.14 0.1Q2 D Flat Lake Wohlford 0.12 0.1Q2 D Moderate Lake Wohlford 0.12 0.1Q2 D Steep Lake Wohlford 0.12 ATTACHMENT 7 – NRCS Soil Map Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/9/2020 Page 1 of 4 36 0 9 5 4 0 36 0 9 6 0 0 36 0 9 6 6 0 36 0 9 7 2 0 36 0 9 7 8 0 36 0 9 8 4 0 36 0 9 9 0 0 36 0 9 5 4 0 36 0 9 6 0 0 36 0 9 6 6 0 36 0 9 7 2 0 36 0 9 7 8 0 36 0 9 8 4 0 36 0 9 9 0 0 502660 502720 502780 502840 502900 502960 503020 503080 503140 503200 502660 502720 502780 502840 502900 502960 503020 503080 503140 503200 32° 37' 36'' N 11 6 ° 5 8 ' 1 8 ' ' W 32° 37' 36'' N 11 6 ° 5 7 ' 5 6 ' ' W 32° 37' 24'' N 11 6 ° 5 8 ' 1 8 ' ' W 32° 37' 24'' N 11 6 ° 5 7 ' 5 6 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 100 200 400 600 Feet 0 35 70 140 210 Meters Map Scale: 1:2,580 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons A A/D B B/D C C/D D Not rated or not available Soil Rating Lines A A/D B B/D C C/D D Not rated or not available Soil Rating Points A A/D B B/D C C/D D Not rated or not available Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 15, May 27, 2020 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Aug 18, 2018—Aug 22, 2018 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/9/2020 Page 2 of 4 Hydrologic Soil Group Map unit symbol Map unit name Rating Acres in AOI Percent of AOI DaC Diablo clay, 2 to 9 percent slopes D 12.7 64.1% DaD Diablo clay, 9 to 15 percent slopes, warm MAAT C 7.1 35.9% Totals for Area of Interest 19.8 100.0% Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (A/D, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (A/D, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/9/2020 Page 3 of 4 Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Hydrologic Soil Group—San Diego County Area, California Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/9/2020 Page 4 of 4 Vault HMP\ Detention\ WQ Discharge vs Elevation Table Bottom orifice diameter:3.50 "Top orifice diameter:4 " Number:1 Number:0 Cg-low:0.61 Cg-low:0.61 invert elev:0.00 ft invert elev:3.00 ft Middle orifice diameter:3.0 "Emergency weir: number of orif:0 Invert:3.00 ft Cg-middle:0.61 Weir Length (ft)10.0 ft invert elev:2.50 ft Box riser 2' x 3' h H/D-low H/D-mid H/D-top H/D-peak Qlow-orif Qlow-weir Qtot-low Qmid-orif Qmid-weir Qtot-med Qtop-orif Qtop-weir Qtot-top Qpeak-top Qtot (ft)----(cfs)(cfs)(cfs)(cfs)(cfs)(cfs)(cfs)(cfs)(cfs)(cfs)(cfs) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0000 0.25 0.86 0.00 0.00 0.00 0.11 0.09 0.09 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.0924 0.50 1.71 0.00 0.00 0.00 0.19 0.25 0.19 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.1946 0.75 2.57 0.00 0.00 0.00 0.25 0.32 0.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.2542 1.00 3.43 0.00 0.00 0.00 0.30 0.35 0.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.3023 1.25 4.29 0.00 0.00 0.00 0.34 0.78 0.34 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.3437 1.50 5.14 0.00 0.00 0.00 0.38 2.67 0.38 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.3806 1.75 6.00 0.00 0.00 0.00 0.41 7.88 0.41 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.4142 2.00 6.86 0.00 0.00 0.00 0.45 19.28 0.45 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.4454 2.25 7.71 0.00 0.00 0.00 0.47 40.97 0.47 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.4744 2.50 8.57 0.00 0.00 0.00 0.50 78.48 0.50 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.5018 2.75 9.43 1.00 0.00 0.00 0.53 138.93 0.53 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.5278 3.00 10.29 2.00 0.00 0.00 0.55 231.32 0.55 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.5526 3.25 11.14 3.00 0.75 0.30 0.58 366.64 0.58 0.00 0.00 0.00 0.00 0.00 0.00 4.16 4.7387 3.50 12.00 4.00 1.50 0.60 0.60 558.16 0.60 0.00 0.00 0.00 0.00 0.00 0.00 11.77 12.3723 3.75 12.86 5.00 2.25 0.90 0.62 821.57 0.62 0.00 0.00 0.00 0.00 0.00 0.00 21.63 22.2499 4.00 13.71 6.00 3.00 1.20 0.64 1175.20 0.64 0.00 0.00 0.00 0.00 0.00 0.00 33.30 33.9421 4.25 14.57 7.00 3.75 1.50 0.66 1640.27 0.66 0.00 0.00 0.00 0.00 0.00 0.00 46.54 47.2008 4.50 15.43 8.00 4.50 1.80 0.68 2241.01 0.68 0.00 0.00 0.00 0.00 0.00 0.00 61.18 61.8585 4.75 16.29 9.00 5.25 2.10 0.70 3004.94 0.70 0.00 0.00 0.00 0.00 0.00 0.00 77.09 77.7924 5.00 17.14 10.00 6.00 2.40 0.72 3963.05 0.72 0.00 0.00 0.00 0.00 0.00 0.00 94.19 94.9072 5.25 18.00 11.00 6.75 2.70 0.74 5149.97 0.74 0.00 0.00 0.00 0.00 0.00 0.00 112.39 113.1264 5.50 18.86 12.00 7.50 3.00 0.76 6604.23 0.76 0.00 0.00 0.00 0.00 0.00 0.00 131.63 132.3866 Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing Factors BMP Design Manual -Appendices March 2019 G-36 G.2.5 Sizing Factors for "Cistern" BMP Table G.2-6 presents sizing factors for calculating the required volume (V1) for a cistern BMP. In this context, a "cistern" is a detention facility that stores runoff and releases it at a controlled rate. A cistern can be a component of a harvest and use system, however the sizing factor method will not account for any retention occurring in the system. The sizing factors were developed assuming runoff is released from the cistern. The sizing factors presented in this section are to meet the hydromodification management performance standard only. The cistern BMP is based on the following assumptions: • Cistern configuration: The cistern is modeled as a 4-foot tall vessel. However, designers could use other configurations (different cistern heights), as long as the lower outlet orifice is sized to properly restrict outflows and the minimum required volume is provided. • Cistern upper outlet: The upper outlet from the cistern would consist of a weir or other flow control structure with the overflow invert set at an elevation of 7/8 of the water height associated with the required volume of the cistern – V1. For the assumed 4-foot water depth in the cistern associated with the sizing factor analysis, the overflow invert is assumed to be located at an elevation of 3.5 feet above the bottom of the cistern. The overflow weir would be sized to pass the peak design flow based on the tributary drainage area. How to use the sizing factors: Obtain sizing factors from Table G.2-6 based on the project's lower flow threshold fraction of Q2, hydrologic soil group, post-project slope, and rain gauge (rainfall basin). Multiply the area tributary to the structural BMP (A, square feet) by the area weighted runoff factor (C, unitless) (see Table G.2- 1) by the sizing factors to determine the required volume (V, cubic feet). Select a low flow orifice that will discharge the lower flow threshold flow at the overflow elevation (i.e. when there is 3.5 feet of head over the lower outlet orifice or adjusted head as appropriate if the cistern overflow elevation is not 3.5 feet tall). The civil engineer shall provide the necessary volume of the BMP and the lower outlet orifice detail on the plans. Additional steps to use this BMP as a combined pollutant control and flow control BMP: A cistern could be a component of a full retention, partial retention, or no retention BMP depending on how the outflow is disposed. However use of the sizing factor method for design of the cistern in a combined pollutant control and flow control system is not recommended. The sizing factor method for designing a cistern does not account for any retention or storage occurring in BMPs combined with the cistern (i.e., cistern sized using sizing factors may be larger than necessary because sizing factor method does not recognize volume losses occurring in other elements of a combined system). Furthermore, when the cistern is designed using the sizing factor method, the cistern outflow must be set to the low flow threshold flow for the drainage area, which may be inconsistent with requirements for other elements of a combined system. To optimize a system in which a cistern provides temporary storage for runoff to be either used onsite (harvest and use), infiltrated, or biofiltered, project-specific continuous simulation modeling is recommended. Refer to Sections 5.6 and 6.3.6. Stage Storage Vault HMP-1 Depth (ft) Area (sq ft) Volume (cu ft) Volume Total (cu ft) Storage (ac-ft) 0.00 16800 0 0.25 16800 4,200 4,200 0.096419 0.50 16800 4,200 8,400 0.192837 0.75 16800 4,200 12,600 0.289256 1.00 16800 4,200 16,800 0.385675 1.25 16800 4,200 21,000 0.482094 1.50 16800 4,200 25,200 0.578512 1.75 16800 4,200 29,400 0.674931 2.00 16800 4,200 33,600 0.77135 2.25 16800 4,200 37,800 0.867769 2.50 16800 4,200 42,000 0.964187 2.75 16800 4,200 46,200 1.060606 3.00 16800 4,200 50,400 1.157025 3.25 16800 4,200 54,600 1.253444 3.50 16800 4,200 58,800 1.349862 3.75 16800 4,200 63,000 1.446281 4.00 16800 4,200 67,200 1.5427 4.25 16800 4,200 71,400 1.639118 4.50 16800 4,200 75,600 1.735537 4.75 16800 4,200 79,800 1.831956 5.00 16800 4,200 84,000 1.928375 5.25 16800 4,200 88,200 2.024793 5.50 16800 4,200 92,400 2.121212 Elevation QAVG (CFS)DV (CF)DT (HR)Total T 0.00 0.25 0.0924 4200.0 12.6212 48.58 0.50 0.1946 4200.0 5.9939 35.96 0.75 0.2542 4200.0 4.5891 29.97 1.00 0.3023 4200.0 3.8596 25.38 1.25 0.3437 4200.0 3.3946 21.52 1.50 0.3806 4200.0 3.0653 18.12 1.75 0.4142 4200.0 2.8163 15.06 2.00 0.4454 4200.0 2.6196 12.24 2.25 0.4744 4200.0 2.4591 9.62 2.50 0.5018 4200.0 2.3248 7.16 2.75 0.5278 4200.0 2.2104 4.84 3.00 0.5526 4200.0 2.1114 2.63 3.25 4.7387 4200.0 0.2462 0.52 3.50 12.3723 4200.0 0.0943 0.27 3.75 22.2499 4200.0 0.0524 0.18 4.00 33.9421 4200.0 0.0344 0.12 4.25 47.2008 4200.0 0.0247 0.09 4.50 61.8585 4200.0 0.0189 0.07 4.75 77.7924 4200.0 0.0150 0.05 5.00 94.9072 4200.0 0.0123 0.03 5.25 113.1264 4200.0 0.0103 0.02 5.50 132.3866 4200.0 0.0088 0.01 Draw Down Otay Ranch Town Center EXHIBIT "A" Maintenance Recommendations andEXHIBIT "B" Frequency Inspection Operation and Maintenance Plan (IOMP) INSPECTION FREQUENCY MAINTENANCE FREQUENCY MAINTENANCE METHOD QUANTITY SHEET NUMBERS WEEKLY AS-NEEDED MOW AS NECESSARY 66768 SF 20003-4~9 ANNUAL AS-NEEDED MAINTAIN DRIVEWAYS, CLEAN UP AREA DRAINS 1 20003-4~9 SOURCE CONTROL ELEMENTS DESCRIPTION: STORM DRAIN STENCILING ANNUAL BI-ANNUAL REPAINT AS NECESSARY 1 20003-4~9 BI-ANNUAL 6-12 MONTHS AS NEEDED REPLCMNT OF SOIL MATERIAL REMOVE DEBRIS AS NEEDED 3 O&M RESPONSIBLE PARTY DESIGNEE: PROPERTY OWNDER: INCLUDED IN O&M MANUALBMP DESCRIPTION SITE DESIGN ELEMENTS SITE DESIGN, SOURCE CONTROL AND POLLUTANT CONTROL BMP OPERATION + MAINTENANCE PROCEDURE DESCRIPTION:LANDSCAPE DESCRIPTION:RUNOFF COLLECTION POLLUTANT CONTROL BMP(S) STORM WATER MANAGEMENT AND DISCHARGE CONTROL MAINTENANCE AGREEMENT APPROVAL NO.: NO YES NO DESCRIPTION:PROPRIETARY BIOFILTRATION UNIT 223278 sf Otay Ranch Town Center Otay Ranch Town Center MU/R MU/R PS PS PS PS MU/R MU/R MU/R P P MU/R MU/R MU/R MU/R P 4 9 7 3 5 7 10 10 6 7 9 9 LOT 1 LOT 5 LOT 7 LOT 8 LOT 6 LOT 9 LOT 2 LOT 3 LOT 4 LOT A LOT B LOT C LOT D LOT I LOT I LOT H 4 4 " A " " A " 8 SHEET OF HUNSAKER& ASSOCIATES TOWN CENTER FC-1 TENTATIVE MAP/CVT 22-0002 OTAY RANCH City Of Chula Vista, California PREPARED BY: CVT # 22-0002 3 FO R C O N T I N U A T I O N S E E S H E E T 4 FOR CONTINUATION SEE SHEET 5 PS PS PS MU/R MU/R MU/R MU/R MU/R P 4 3 5 7 10 10 7 9 LOT 8 LOT 6 LOT 9 LOT 3 LOT 4 LOT A LOT B LOT C LOT I LOT 10 LOT 10 4 4 " A " " A " 8 SHEET OF HUNSAKER& ASSOCIATES TOWN CENTER FC-1 TENTATIVE MAP/CVT 22-0002 OTAY RANCH City Of Chula Vista, California PREPARED BY: CVT # 22-0002 4 FO R C O N T I N U A T I O N S E E S H E E T 3 FOR CONTINUATION SEE SHEET 5 P PS MU/R P P FC-1 7 FC-1 FC-1 LOT 10 LOT 7 LOT 8 LOT D LOT E LOT F LOT G LOT 10 LOT 10 LOT 10 8 SHEET OF HUNSAKER& ASSOCIATES TOWN CENTER FC-1 TENTATIVE MAP/CVT 22-0002 OTAY RANCH City Of Chula Vista, California PREPARED BY: CVT # 22-0002 5 FOR CONTINUATION SEE SHEET 3 FOR CONTINUATION SEE SHEET 4 Otay Ranch Town Center Otay Ranch Town Center GEOTECHNICAL RECONNAISSANCE REPORT OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA PREPARED FOR FEBRUARY 4, 2022 PROJECT NO. G2883-52-01 GROCON INCORPORATED GEOTECHNICAL • ENVIRONMENTAL MATERIALSO 6960 Flanders Drive • San Diego, California 92121-2974 • Telephone 858.558.6900 • Fax 858.558.6159 Project No. G2883-52-01 February 4, 2022 Brookfield Properties 733 8th Avenue San Diego, California 92101 Attention: Mr. Dan Buoye Subject: GEOTECHNICAL RECONNAISSANCE REPORT OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA Dear Mr. Buoye: In accordance with your request and authorization of our Proposal No. LG-21061 revised January 11, 2022, we prepared this geotechnical reconnaissance report for the proposed Otay Ranch Town Center redevelopment in Chula Vista, California. The accompanying report describes the general site soil and geologic conditions based on a desktop study and presents our findings. We should be contacted to prepare a geotechnical investigation for proposed redevelopment to the property, if planned. Should you have any questions regarding this report, or if we may be of further service, please contact the undersigned at your convenience. Very truly yours, GEOCON INCORPORATED Ken W. Haase PG 9974 Shawn Foy Weedon GE 2714 John Hoobs CEG 1524 KH:SFW:JH:arm (e-mail) Addressee TABLE OF CONTENTS 1. PURPOSE AND SCOPE ...................................................................................................................... 1 2. SITE DESCRIPTION ........................................................................................................................... 2 3. GEOLOGIC SETTING ......................................................................................................................... 3 4. SOIL AND GEOLOGIC CONDITIONS ............................................................................................. 4 4.1 Previously Placed Fill ................................................................................................................. 4 4.2 Otay Formation ........................................................................................................................... 4 5. GROUNDWATER ............................................................................................................................... 5 6. GEOLOGIC HAZARDS ...................................................................................................................... 5 6.1 Faulting and Seismicity .............................................................................................................. 5 6.2 Ground Rupture .......................................................................................................................... 7 6.3 Tsunamis and Seiches ................................................................................................................. 7 6.4 Liquefaction ................................................................................................................................ 7 6.5 Landslides ................................................................................................................................... 7 6.6 Erosion ........................................................................................................................................ 7 6.7 Settlement ................................................................................................................................... 8 7. CONCLUSIONS AND RECOMMENDATIONS ................................................................................ 9 7.1 General ........................................................................................................................................ 9 7.2 Excavation and Soil Characteristics ......................................................................................... 10 7.3 Seismic Design Criteria ............................................................................................................ 10 7.4 General Grading Recommendations ......................................................................................... 12 7.5 Geotechnical Design ................................................................................................................. 14 7.6 Site Drainage and Moisture Protection ..................................................................................... 15 MAPS AND ILLUSTRATIONS Figure 1, Geologic Map APPENDIX A PREVIOUS BORING LOGS APPENDIX B PREVIOUS LABORATORY TESTING LIST OF REFERENCES Geocon Project No. G2883-52-01 - 1 - February 4, 2022 GEOTECHNICAL RECONNAISSANCE 1. PURPOSE AND SCOPE This report presents the results of a geotechnical reconnaissance related to proposed redevelopment of the Otay Ranch Town Center in the City of Chula Vista, California (see Vicinity Map). The roughly 5- acre property is located north of Birch Road and the Otay Ranch Town Center Mall, south of Olympic Parkway and the Planning Area 12 development, west of Eastlake Parkway and east of State Route 125. The purpose of this study is to review published geotechnical documents and geologic information (see List of References) and evaluate the existing geologic conditions and geologic/geotechnical hazards that may affect the property. Vicinity Map The scope of our study included reviewing published and unpublished geotechnical information of the surrounding area. Appendix A presents the boring logs performed during the referenced investigation. In addition, Appendix B includes the laboratory test results from the previous investigation. The conclusions presented herein are based on a review of the available data and our experience with similar soil and geologic conditions in the surrounding area. The scope of the study included a review of: 1. As-Graded Geotechnical Report, McMillin Otay Ranch, Village 12 and Borrow and Fill Sites Within the Eastern Urban Center, Chula Vista, California, prepared by Geotechnics Incorporated, dated February 16, 2006 (Project No. 0367-012-01, Document No. 05-1029). 2. Preliminary Geotechnical Investigation, Otay Ranch Town Center Addition, Otay Ranch Village 12, 2015 Birch Road, Chula Vista, California, prepared by Geocon Incorporated, dated June 26, 2014 (Project No. G1731-11-01). Geocon Project No. G2883-52-01 - 2 - February 4, 2022 2. SITE DESCRIPTION The existing property consists of the northern parking area for the existing Otay Ranch Town Center mall. The area consists of surface grade asphalt concrete parking on the east and southwest, an outdoor soccer area and playground in the central portion with a landscape construction storage area in the northwest portion. The site was graded between 2004 and 2005 with observation and testing services provided by Geotechnics, Incorporated. The site is relatively flat with elevations between 624 feet Mean Sea Level (MSL) and 614 feet MSL, sloping gently to the southwest. An existing 10- to 15-foot-high cut and fill slope exists on the west limits of the site, descending towards State Route 125. The Existing Site Map shows the current conditions at the site. Based on the previous as-graded map, the site was partially situated over the upper portions of two canyon drainages with fill depths ranging up to about 25 feet at the site. Existing Site Map We understand the proposed redevelopment will consist of constructing 3, multi-family residential lots with commercial space, reconfiguring the existing Town Center Drive entrance and installing a new plaza area in the southeast portion of the site with accommodating utilities, flatwork, and landscaping. The Preliminary Site Plan shows a current concept of the proposed improvements. Geocon Project No. G2883-52-01 - 3 - February 4, 2022 Preliminary Site Plan 3. GEOLOGIC SETTING The site is in the eastern portion of the coastal plain within the southern portion of the Peninsular Ranges Geomorphic Province of southern California. The Peninsular Ranges is a geologic and geomorphic province that extends from the Imperial Valley to the Pacific Ocean and from the Transverse Ranges to the north and into Baja California to the south. The coastal plain of San Diego County is underlain by a thick sequence of relatively undisturbed and non-conformable sedimentary rocks that thicken to the west and range in age from Upper Cretaceous through the Pleistocene with intermittent deposition. The sedimentary units are deposited on bedrock Cretaceous to Jurassic age igneous and metavolcanic rocks. Geomorphically, the coastal plain is characterized by a series of 21, stair-stepped marine terraces (younger to the west) that have been dissected by west flowing rivers. The coastal plain is a relatively stable block that is dissected by relatively few faults consisting of the potentially active La Nacion Fault Zone and the active Rose Canyon Fault Zone. The Peninsular Ranges Province is also dissected by the Elsinore Fault Zone that is associated with and sub-parallel to the San Andreas Fault Zone, which is the plate boundary between the Pacific and North American Plates. Geocon Project No. G2883-52-01 - 4 - February 4, 2022 The site consists of Oligocene-age (Tertiary) Otay Formation that generally consists of sandstones with interbeds of claystones and siltstones with a reported maximum thickness of roughly 400 feet. The Otay Formation contains multiple layers of bentonitic claystone that is highly expansive and has low shear strength. The Regional Geologic Map shows the geologic units around the site. Regional Geologic Map 4. SOIL AND GEOLOGIC CONDITIONS Based on our review of existing geologic information, the site is likely underlain by previously placed fill and the Otay Formation. The geologic units are described herein in order of increasing age. 4.1 Previously Placed Fill Previously placed fill is present across most of the site based on the referenced as-graded map. The fill depths likely range up to about 25 feet on the site. We expect the fill soil consists of medium dense, damp to moist, sandy silts and clays and possess a “very low” to “high” expansion potential (expansion index of 130 or less) and a “S0” sulfate exposure. We expect the upper 2 to 3 feet of the existing fill will require remedial grading. However, deeper removals may be required during relocation of utilities or from demolishing foundations. The previously placed fill is suitable for the support of the proposed fill and structural loads. 4.2 Otay Formation Tertiary-age Otay Formation located below the previously placed fill at may be exposed at grade in previous cut areas. This unit consists of interbeds of dense to very dense, slightly cemented, silty to Geocon Project No. G2883-52-01 - 5 - February 4, 2022 clayey sandstone and hard, siltstone and claystone layers. Excavations will generally be possible with heavy-duty grading equipment with heavy effort; however, moderately to highly cemented zones may create very difficult ripping and generate oversize cemented cobbles and boulders. The soil from this unit normally possesses a “very low” to “medium” expansion potential (expansion index of 90 or less); however, the claystones may possess a “high” expansion potential (expansion index of 91 to 130). The Otay Formation is suitable for the support of proposed fill and structural loads. 5. GROUNDWATER We expect groundwater exists deeper than 100 feet below existing grade at the property; therefore, we do not expect groundwater to adversely impact future development. Seepage may be encountered at the fill/formational contact and within the previous canyon drainages. Groundwater elevations and seepage conditions are dependent on seasonal precipitation, irrigation, and land use, among other factors, and vary as a result. Seepage conditions can develop due to over watering or poor drainage practices. In addition, localized seepage conditions are occasionally encountered within deeper fills when drilled caisson foundations are excavated. 6. GEOLOGIC HAZARDS 6.1 Faulting and Seismicity A review of geologic literature and experience with the soil and geologic conditions in the general area indicate that known active, potentially active, or inactive faults are not located at the site. An active fault is defined by the California Geological Survey (CGS) as a fault showing evidence for activity within the last 11,700 years. The site is not located within a State of California Earthquake Fault Zone. The USGS has developed a program to evaluate the approximate location of regional faulting in the area of properties. The following figure shows the location of the existing faulting in the San Diego County and Southern California region. The fault traces are shown as solid, dashed, and dotted that represent well-constrained, moderately constrained and inferred, respectively. The fault line colors represent fault with ages less than 150 years (red), 15,000 years (orange), 130,000 years (green), 750,000 years (blue, not shown) and 1.6 million years (black). Geocon Project No. G2883-52-01 - 6 - February 4, 2022 Faults in Southern California The San Diego County and Southern California region is seismically active. The following figure presents the occurrence of earthquakes with a magnitude greater than 2.5 from the period of 1900 through 2015 according to the Bay Area Earthquake Alliance website. Earthquakes in Southern California Geocon Project No. G2883-52-01 - 7 - February 4, 2022 Considerations important in seismic design include the frequency and duration of motion and the soil conditions underlying the site. Seismic design of structures should be evaluated in accordance with the California Building Code (CBC) guidelines currently adopted by the local agency. 6.2 Ground Rupture Ground surface rupture occurs when movement along a fault is sufficient to cause a gap or rupture where the upper edge of the fault zone intersects the earth surface. The potential for ground rupture is considered to be negligible due to the absence of active faults at the subject site. 6.3 Tsunamis and Seiches A tsunami is a series of long-period waves generated in the ocean by a sudden displacement of large volumes of water. The site is located approximately ten miles from the Pacific Ocean at an elevation greater than 610 feet MSL. Therefore, the risk of a tsunami affecting the site is considered negligible due to the distance of the site from the ocean and elevation. Seiches are standing wave oscillations of an enclosed water body after the original driving force has dissipated. Driving forces are typically caused by seismic ground shaking. The site is not located near a body of water; therefore, the risk of a seiche affecting the site is considered negligible. 6.4 Liquefaction Liquefaction typically occurs when a site is located in a zone with seismic activity, on-site soils are cohesionless or silt/clay with low plasticity, groundwater is encountered, and soil relative densities are less than about 70 percent. If the four previous criteria are met, a seismic event could result in a rapid pore-water pressure increase from the earthquake-generated ground accelerations. Seismically induced settlement may occur whether the potential for liquefaction exists or not. Due to the lack of a near surface groundwater table and the very dense nature of the fill and formational materials, the potential for liquefaction and seismically induced settlement occurring at the site is considered negligible. 6.5 Landslides We did not observe evidence of previous or incipient slope instability at the site during our study and the property is relatively flat. Published geologic mapping indicates landslides are not present on or adjacent to the site. Therefore, we opine the potential for a landslide is not a concern for this project. 6.6 Erosion The site is relatively flat and is not located adjacent to the Pacific Ocean coast or a free-flowing drainage where active erosion is occurring. Provided the engineering recommendations herein are Geocon Project No. G2883-52-01 - 8 - February 4, 2022 followed and the project civil engineer prepares the grading plans in accordance with generally accepted regional standards, we do not expect erosion to be a major impact to site development. In addition, we expect the proposed development would not increase the potential for erosion if properly designed. 6.7 Settlement Fill is present across the majority of the site approaching maximum depths of about 25 feet. Fills are subject to long term settlement under gravity loading and also subject to settlements due to building loads. Based on previous experience for fill soils that are roughly 15 to 20 years old, long-term settlements due to gravity loading of roughly 0.1 percent could occur resulting in settlements of about 0.3 inches for a 20- to 25-foot deep fill. We should provide estimated settlements in the locations of the proposed buildings once a grading plan has been prepared with building locations. Geocon Project No. G2883-52-01 - 9 - February 4, 2022 7. CONCLUSIONS AND RECOMMENDATIONS 7.1 General 7.1.1 From a geotechnical engineering standpoint, we opine adverse soil or geologic conditions do not exist at the property and that the proposed redevelopment project can be performed. 7.1.2 Based on a review of the referenced geologic information and our experience in the area, we expect the site is generally underlain by previously placed fill with a maximum thickness of about 25 feet overlying the Otay Formation. The Otay Formation may be present at or near existing grade in the southwest and northeast portions of the site. The upper portion of the fill soil will require remedial grading where present across the site. The fill soil can be reused as new compacted fill. We should perform a geotechnical investigation to provide the design and remedial grading recommendations for the project once architecture and grading plans have been prepared. 7.1.3 We expect that formational materials will be exposed at or near proposed finish grades for portions of the proposed buildings. Due to the dense nature of the formational material, we expect the upper 5 feet of formational material to be removed and replaced with properly compacted fill. 7.1.4 Groundwater extends deeper than 100 feet below the site and will not affect development. It is not uncommon for near surface seepage conditions to develop from excessive irrigation where none previously existed due to the permeability characteristics of the geologic units on site. 7.1.5 We do not expect significant slopes or retaining walls will be constructed. Therefore, slope instability for planned and existing permanent slopes will not be a consideration for redevelopment. 7.1.6 We expect that most of the on-site soils will generally have a “low” to “medium” expansion potential (expansion index between 21 and 90) and an “S0” corrosion potential for design. Therefore, expansive soils will be a consideration for redevelopment. 7.1.7 Grading plans for future redevelopment and improvement for this property are not currently available. We should be contacted to perform a geotechnical investigation if the property will be redeveloped. Geocon Project No. G2883-52-01 - 10 - February 4, 2022 7.2 Excavation and Soil Characteristics 7.2.1 Excavation of the in-situ soil should be possible with moderate to heavy effort using conventional heavy-duty equipment. Some cemented zones exist in the formational materials that may require localized very difficult excavation and generation of oversize material, if encountered. 7.2.2 We expect the existing soil is considered to be “expansive” (expansion index [EI] of greater than 20) as defined by 2019 California Building Code (CBC) Section 1803.5.3. Table 7.2.1 presents soil classifications based on the expansion index. We expect the soil onsite to possess a “very low” to “high” expansion potential (expansion index of 130 or less) in accordance with ASTM D 4829. TABLE 7.2.1 EXPANSION CLASSIFICATION BASED ON EXPANSION INDEX Expansion Index (EI) ASTM D 4829 Expansion Classification 2019 CBC Expansion Classification 0 – 20 Very Low Non-Expansive 21 – 50 Low Expansive 51 – 90 Medium 91 – 130 High Greater Than 130 Very High 7.2.3 We expect the onsite fill soils and formational materials will possess an “S0” sulfate exposure to concrete structures in contact with soil as defined by 2019 CBC Section 1904 and ACI 318- 14 Chapter 19. The presence of water-soluble sulfates is not a visually discernible characteristic; therefore, other soil samples from the site could yield different concentrations. Additionally, over time landscaping activities (i.e., addition of fertilizers and other soil nutrients) may affect the concentration. 7.2.4 Geocon Incorporated does not practice in the field of corrosion engineering. Therefore, if improvements that could be susceptible to corrosion are planned, further evaluation by a corrosion engineer should be performed. 7.3 Seismic Design Criteria 7.3.1 Table 7.3.1 summarizes site-specific design criteria obtained from the 2019 California Building Code (CBC; Based on the 2018 International Building Code [IBC] and ASCE 7- 16), Chapter 16 Structural Design, Section 1613 Earthquake Loads. We used the computer program U.S. Seismic Design Maps, provided by the Structural Engineers Association Geocon Project No. G2883-52-01 - 11 - February 4, 2022 (SEA) to calculate the seismic design parameters. The short spectral response uses a period of 0.2 second. We evaluated the Site Class based on the discussion in Section 1613.2.2 of the 2019 CBC and Table 20.3-1 of ASCE 7-16. The buildings and improvements should be designed using a Site Class C. The values presented herein are for the risk-targeted maximum considered earthquake (MCER). Sites designated as Site Class D, E and F may require additional analyses if requested by the project structural engineer and client. TABLE 7.3.1 2019 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2019 CBC Reference Site Class C Section 1613.2.2 Fill Thickness, T (feet) T<20 -- MCER Ground Motion Spectral Response Acceleration – Class B (short), SS 0.748g Figure 1613.2.1(1) MCER Ground Motion Spectral Response Acceleration – Class B (1 sec), S1 0.273g Figure 1613.2.1(2) Site Coefficient, FA 1.201 Table 1613.2.3(1) Site Coefficient, FV 1.500* Table 1613.2.3(2) Site Class Modified MCER Spectral Response Acceleration (short), SMS 0.898g Section 1613.2.3 (Eqn 16-36) Site Class Modified MCER Spectral Response Acceleration – (1 sec), SM1 0.410g* Section 1613.2.3 (Eqn 16-37) 5% Damped Design Spectral Response Acceleration (short), SDS 0.599g Section 1613.2.4 (Eqn 16-38) 5% Damped Design Spectral Response Acceleration (1 sec), SD1 0.273g* Section 1613.2.4 (Eqn 16-39) 7.3.2 Table 7.3.2 presents the mapped maximum considered geometric mean (MCEG) seismic design parameters for projects located in Seismic Design Categories of D through F in accordance with ASCE 7-16. TABLE 7.3.2 2019 CBC SITE ACCELERATION DESIGN PARAMETERS Parameter Value ASCE 7-16 Site Class C -- Fill Thickness, T (Feet) T<20 -- Mapped MCEG Peak Ground Acceleration, PGA 0.324g Figure 22-9 Site Coefficient, FPGA 1.200 Table 11.8-1 Site Class Modified MCEG Peak Ground Acceleration, PGAM 0.389g Section 11.8.3 (Eqn 11.8-1) Geocon Project No. G2883-52-01 - 12 - February 4, 2022 7.3.3 Conformance to the criteria in Tables 7.3.1 and 7.3.2 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 avoid all damage, since such design may be economically prohibitive. 7.3.4 The project structural engineer and architect should evaluate the appropriate Risk Category and Seismic Design Category for the planned structures. The values presented herein assume a Risk Category of II and resulting in a Seismic Design Category D. Table 7.3.3 presents a summary of the risk categories in accordance with ASCE 7-16. TABLE 7.3.3 ASCE 7-16 RISK CATEGORIES Risk Category Building Use Examples I Low risk to Human Life at Failure Barn, Storage Shelter II Nominal Risk to Human Life at Failure (Buildings Not Designated as I, III or IV) Residential, Commercial and Industrial Buildings III Substantial Risk to Human Life at Failure Theaters, Lecture Halls, Dining Halls, Schools, Prisons, Small Healthcare Facilities, Infrastructure Plants, Storage for Explosives/Toxins IV Essential Facilities Hazardous Material Facilities, Hospitals, Fire and Rescue, Emergency Shelters, Police Stations, Power Stations, Aviation Control Facilities, National Defense, Water Storage 7.4 General Grading Recommendations 7.4.1 Grading should be performed in accordance with the recommendations provided in this report and the local grading ordinance. Geocon Incorporated should observe the grading operations on a full-time basis and provide testing during the fill placement. 7.4.2 Prior to commencing grading, a preconstruction conference should be held at the site with the agency inspector, developer, grading and underground contractors, civil engineer, and geotechnical engineer in attendance. Special soil handling and/or the grading plans can be discussed at that time. 7.4.3 Site preparation should begin with the removal of deleterious material, debris, and vegetation. The depth of vegetation removal should be such that material exposed in cut areas or soil to be used as fill is relatively free of organic matter. Material generated during Geocon Project No. G2883-52-01 - 13 - February 4, 2022 stripping and/or site demolition should be exported from the site. Asphalt and concrete should not be mixed with the fill soil unless approved by the Geotechnical Engineer. 7.4.4 Abandoned foundations and buried utilities (if encountered) should be removed and the resultant depressions and/or trenches should be backfilled with properly compacted material as part of the remedial grading. 7.4.5 We expect the proposed structures will be supported on a shallow foundation system founded in compacted fill. Where formational material is exposed at grade or less than 5 feet of fill is present, the upper 5 feet below finish grade or 2 feet below the proposed foundations (whichever results in a deeper excavation) should be excavated and replaced with properly compacted fill. Where previously placed fill greater than 5 feet is present below the proposed structures, the upper 2 to 3 feet of material should be ripped, moisture conditioned and recompacted prior to receiving improvements. The excavations should extend at least 10 feet laterally outside of the proposed foundation system, where possible. 7.4.6 In areas of proposed improvements outside of the building areas, the upper 1 to 2 feet of existing soil should be processed, moisture conditioned as necessary and recompacted. Deeper excavations may be required in areas where loose or saturated materials are encountered. The excavations should extend at least 2 feet laterally outside of the improvement area, where possible. Table 7.4.1 provides a summary of the remedial grading recommendations. TABLE 7.4.1 SUMMARY OF REMEDIAL GRADING RECOMMENDATIONS Area Remedial Grading Excavation Requirements Proposed Buildings (Formational Material or Less Than 5 Feet of Fill) Excavate 5 Feet Below Pad Grade and 2 Feet Below Footings Proposed Buildings (Previously Placed Fill) Remedial Grading of Upper 2 to 3 Feet of Existing Fill Site Development (Outside Building Areas) Process Upper 1 to 2 Feet of Existing Materials Lateral Grading Limits 10 Feet Outside of Buildings 2 Feet Outside of Improvement Areas Exposed Bottoms of Excavations Scarify Upper 12 Inches 7.4.7 The bottom of the excavations should be sloped 1 percent to the adjacent street or deepest fill. Prior to fill soil being placed, the existing ground surface should be scarified, moisture conditioned as necessary, and compacted to a depth of at least 12 inches. Deeper Geocon Project No. G2883-52-01 - 14 - February 4, 2022 excavations may be required if saturated or loose fill soil is encountered. A representative of Geocon should be on-site during excavations to evaluate the limits of the remedial grading. 7.4.8 The site should then be brought to final subgrade elevations with fill compacted in layers. In general, the existing soil is suitable for use from a geotechnical engineering standpoint as fill if relatively free from vegetation, debris, and other deleterious material. Layers of fill should be about 6 to 8 inches in loose thickness and no thicker than will allow for adequate bonding and compaction. Fill, including backfill and scarified ground surfaces, should be compacted to a dry density of at least 90 percent of the laboratory maximum dry density near to slightly above optimum moisture content in accordance with ASTM Test Procedure D 1557. Fill materials placed below optimum moisture content may require additional moisture conditioning prior to placing additional fill. The upper 12 inches of subgrade soil underlying pavement should be compacted to a dry density of at least 95 percent of the laboratory maximum dry density near to slightly above optimum moisture content shortly before paving operations. 7.4.9 The City of Chula Vista requires additional removals and grading requirements within the street and right-of-way areas. Based on the City of Chula Vista, the upper 5 feet of fill and upper 3 feet of formational materials within the public right of way areas should possess an expansion index of 90 or less. Additional removals of formational materials may be required if the expansion index is greater than 90. 7.4.10 Import fill (if necessary) should consist of the characteristics presented in Table 7.3.2. Geocon Incorporated should be notified of the import soil source and should perform laboratory testing of import soil prior to its arrival at the site to determine its suitability as fill material. TABLE 7.3.2 SUMMARY OF IMPORT FILL RECOMMENDATIONS Soil Characteristic Values Expansion Potential “Very Low” to “Medium” (Expansion Index of 90 or less) Particle Size Maximum Dimension Less Than 3 Inches Generally Free of Debris 7.5 Geotechnical Design 7.5.1 The following geotechnical design items should be considered during due diligence. Geocon Project No. G2883-52-01 - 15 - February 4, 2022 We expect that shallow conventional foundations that provide moderate bearing values can be used to support the proposed residential and mixed-use buildings founded in compacted fill. Typical subgrade preparation time of exterior concrete flatwork and sidewalk is expected. Expansive soils should be considered. We expect that relatively low R-Value laboratory test results for subgrade soils will be encountered that will require thicker pavement sections for the parking lots and driveways. Typical subgrade preparation time of pavement areas are expected. Typical design and use of landscape area drains and building roof drains is expected. Control of surface drainage and its discharge and containment to storm water management devices will be an important design consideration to reduce the potential for erosion and maintaining the geotechnical design parameters of the project. Potential elevated long-term maintenance costs for surface improvements that includes sidewalks and flatwork due to the anticipated “low” to “high” expansive soils at finish grade. 7.6 Site Drainage and Moisture Protection 7.6.1 Adequate site drainage is critical to reduce the potential for differential soil movement, erosion, and subsurface seepage. Under no circumstances should water be allowed to pond adjacent to footings and improvements. The site should be graded and maintained such that surface drainage is directed away from structures in accordance with 2019 CBC 1804.4 or other applicable standards. In addition, surface drainage should be directed away from the top of slopes into swales or other controlled drainage devices. Roof and pavement drainage should be directed into conduits that carry runoff away from the proposed structure. 7.6.2 Underground utilities should be leak free. Utility and irrigation lines should be checked periodically for leaks, and detected leaks should be repaired promptly. Detrimental soil movement could occur if water is allowed to infiltrate the soil for prolonged periods of time. 7.6.3 Landscaping planters adjacent to paved areas are not recommended due to the potential for surface or irrigation water to infiltrate the pavement’s subgrade and base course. Area drains to collect excess irrigation water and transmit it to drainage structures or impervious above- grade planter boxes can be used. In addition, where landscaping is planned adjacent to the pavement, construction of a cutoff wall along the edge of the pavement that extends at least 6 inches below the bottom of the base material should be considered. B-8 B-7 B-6 B-11 B-10 B-12 B-13 B-2 B-3 B-1 B-5 B-4 B-9 (3') (3') (5'+) (9.5') (4') (6') (5'+) (5'+) (15.5') (6') (5'+) (18.5') (5'+) To Qpf/ Qpf/ Qpf/ Qpf/ Qpf/ 605 604 602 602 609 606 600 594 606611 613 606 613 601 608 611 616 612 616 617 615 621 614 610 613 604 602 613 604 602 603 608 To To To 620 614 606 ? ? ? ? ? ? To APPROX. SITE LIMITS 6960 FLANDERS DRIVE - SAN DIEGO, CALIFORNIA 92121 - 2974 PHONE 858 558-6900 - FAX 858 558-6159 SHEET OF PROJECT NO. SCALE DATE FIGURE Plotted:02/04/2022 8:53AM | By:ALVIN LADRILLONO | File Location:Y:\PROJECTS\G2883-52-01 (OR Town Center)\SHEETS\G2883-52-01 Geo Map.dwg GEOTECHNICAL ENVIRONMENTAL MATERIALS 1" = GEOLOGIC MAP OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA 60'02 - 04 - 2022 G2883 - 52 - 01 1 1 1 ........PREVIOUSLY PLACED FILL (Geotechnics, Inc. 2005) ........OTAY FORMATION (Dotted Where Buried) ........APPROX. LOCATION OF GEOLOGIC CONTACT ........APPROX. LOCATION OF BORING (Geocon, Inc. 2014) ........APPROX. DEPTH OF FILL (In Feet) ........APPROX. ELEVATION AT BASE OF FILL (In Feet, MSL) GEOCON LEGEND 613 Qpf B-13 To (5'+) APPENDIX A APPENDIX A PREVIOUS BORING LOGS FROM PRELIMINARY GEOTECHNICAL INVESTIGATION OTAY RANCH TOWN CENTER ADDITION OTAY RANCH VILLAGE 12 CHULA VISTA, CALIFORNIA PROJECT NO. G1731-11-01 FOR OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA PROJECT NO. G2883-52-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy SILT; trace gravel Very stiff, moist, light brown, Sandy SILT to Silty, fine SAND -Becomes damp to moist, light olive brown -Trace bentonite OTAY FORMATION (To) Very dense, damp, grayish to yellowish brown, Sandy SILTSTONE; slightly cemented; micaceous BORING TERMINATED AT 19 FEET No groundwater encountered ML ML/SM ML B1-1 B1-2 B1-3 B1-4 B1-5 21.8 21.1 28.6 45 60 45 73/11.5" 97.1 102.7 95.1 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 1 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)619' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 12 14 16 18 Figure A-1, Log of Boring B 1, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy CLAY Very stiff, moist, light olive brown, Sandy CLAY to Clayey fine SAND Dense, damp, light brown to grayish brown, Silty, very fine SAND -Becomes moist -Trace clay OTAY FORMATION (To) Very stiff to hard, moist, gray, Sandy SILTSTONE; micaceous BORING TERMINATED AT 18 FEET No groundwater encountered CL CL/SC SM ML B2-1 B2-2 B2-3 B2-4 B2-5 19.6 26.0 22.7 47 52 53 42 52 105.9 96.6 99.8 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 2 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)621' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 12 14 16 18 Figure A-2, Log of Boring B 2, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy CLAY -Becomes very stiff, olive brown to brown OTAY FORMATION (To) Very dense, dry to damp, grayish brown, Silty, fine SANDSTONE; moderately to strongly cemented -Becomes damp, light grayish brown BORING TERMINATED AT 10 FEET No groundwater encountered CL SM B3-1 B3-2 B3-3 B3-4 22.957 50/5" 80 101.5 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 3 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)620' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 Figure A-3, Log of Boring B 3, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy CLAY; trace gravel Dense, moist, light gray, Clayey, fine SAND BORING TERMINATED AT 5 FEET No groundwater encountered CL SC B4-1 B4-2 19.952106.0 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 4 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)617' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 Figure A-4, Log of Boring B 4, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy CLAY -Becomes very stiff, light brown BORING TERMINATED AT 15 FEET No groundwater encountered CLB5-1 B5-2 26.05996.9 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 5 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)618' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 Figure A-5, Log of Boring B 5, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, damp, olive brown, Sandy CLAY -Becomes moist, micaceous OTAY FORMATION (To) Very dense, moist, brown to olive brown, Silty, very fine SANDSTONE; micaceous Hard, moist, grayish brown, Sandy SILTSTONE; micaceous BORING TERMINATED AT 9.75 FEET No groundwater encountered CL SM ML B6-1 B6-2 B6-3 B6-4 26.163 72/11.5" 86/9.5" 99.0 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 6 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)618' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 Figure A-6, Log of Boring B 6, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, damp to moist, light olive brown, Sandy SILT; trace organics; trace gravel -Micaceous OTAY FORMATION (To) Hard, damp to moist, light grayish brown, Sandy SILTSTONE; micaceous Very dense, damp, light brown, Silty SANDSTONE; micaceous BORING TERMINATED AT 10 FEET No groundwater encountered ML ML SM B7-1 B7-2 B7-3 B7-4 26.451 80/10" 79/11.5" 93.5 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 7 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)618' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 Figure A-7, Log of Boring B 7, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 5" ASPHALT CONCRETE over 5" BASE MATERIAL PREVIOUSLY PLACED FILL (Qpf) Stiff, damp to moist, light olive brown, Sandy CLAY Very stiff, damp, Sandy CLAY to Clayey, fine SAND Very stiff, damp, olive brown, Sandy SILT to Silty, fine SAND OTAY FORMATION (To) Very dense, damp, light grayish brown, Silty, fine SANDSTONE; micaceous Hard, damp, gray, Sandy SILTSTONE; micaceous BORING TERMINATED AT 13 FEET No groundwater encountered CL CL/SC ML/SM SM ML B8-1 B8-2 B8-3 B8-4 B8-5 22.2 23.8 43 44 85/11.5 86/10" 102.8 103.7 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 8 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)616' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 12 Figure A-8, Log of Boring B 8, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Medium dense, dry to damp, olive brown, Clayey, fine to coarse SAND; trace gravel Very stiff, moist, light olive brown, Sandy CLAY to Clayey, fine SAND BORING TERMINATED AT 5 FEET No groundwater encountered SC CL/SC B9-1 B9-2 17.241101.0 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 9 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)621' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 Figure A-9, Log of Boring B 9, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Dense, damp, light brown, Silty, fine to medium SAND OTAY FORMATION (To) Very dense, damp, brown, Silty, fine SANDSTONE; micaceous Hard, damp, light brown, Sandy SILTSTONE; micaceous BORING TERMINATED AT 10.75 FEET No groundwater encountered SM SM ML B10-1 B10-2 11.7 18.5 50/5.5" 86/9.5"112.9 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 10 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)622' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 Figure A-10, Log of Boring B 10, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Loose, moist, light brown, Silty, fine SAND to Sandy SILT OTAY FORMATION (To) Very dense, moist, light brown, Silty, fine SANDSTONE BORING TERMINATED AT 15.5 FEET No groundwater encountered SM/ML SM B11-1 B11-2 B11-3 B11-4 12.7 16.6 50/4" 50/5.5" 50/5.5" 105.5 112.1 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 11 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)624' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 6 8 10 12 14 Figure A-11, Log of Boring B 11, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Loose to medium dense, damp, grayish brown, Clayey GRAVEL; up to 2" diameter gravel Very stiff, moist, olive brown, Sandy CLAY; trace gravel; micaceous Dense, moist, light brown, Clayey, fine SAND, to Sandy CLAY; micaceous BORING TERMINATED AT 5 FEET No groundwater encountered GC CL SC/CL B12-1 B12-2 27.04595.2 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 12 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)622' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 Figure A-12, Log of Boring B 12, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 PREVIOUSLY PLACED FILL (Qpf) Stiff, moist, olive brown, Sandy CLAY; trace gravel; micaceous Dense, moist, light brown, Clayey fine SAND to Sandy CLAY; micaceous BORING TERMINATED AT 5 FEET No groundwater encountered CL SC/CL B13-1 B13-2 18.458104.6 ... DRIVE SAMPLE (UNDISTURBED) CME 55 PE N E T R A T I O N RE S I S T A N C E (B L O W S / F T . ) BORING B 13 ... CHUNK SAMPLE DATE COMPLETED ... SAMPLING UNSUCCESSFUL EQUIPMENT ELEV. (MSL.)620' G1731-11-01.GPJ MATERIAL DESCRIPTION LI T H O L O G Y ... STANDARD PENETRATION TEST SOIL CLASS (USCS) GR O U N D W A T E R L. RODRIGUEZ SAMPLE NO. CO N T E N T ( % ) 06-05-2014 SAMPLE SYMBOLS ... WATER TABLE OR SEEPAGE MO I S T U R E BY: ... DISTURBED OR BAG SAMPLE GEOCON DEPTH IN FEET 0 2 4 Figure A-13, Log of Boring B 13, Page 1 of 1 DR Y D E N S I T Y (P . C . F . ) NOTE: PROJECT NO. THE LOG OF SUBSURFACE CONDITIONS SHOWN HEREON APPLIES ONLY AT THE SPECIFIC BORING OR TRENCH LOCATION AND AT THE DATE INDICATED. IT IS NOT WARRANTED TO BE REPRESENTATIVE OF SUBSURFACE CONDITIONS AT OTHER LOCATIONS AND TIMES. G1731-11-01 APPENDIX B APPENDIX B PREVIOUS LABORATORY TESTING FROM PRELIMINARY GEOTECHNICAL INVESTIGATION OTAY RANCH TOWN CENTER ADDITION OTAY RANCH VILLAGE 12 CHULA VISTA, CALIFORNIA PROJECT NO. G1731-11-01 FOR OTAY RANCH TOWN CENTER CHULA VISTA, CALIFORNIA PROJECT NO. G2883-52-01 Geocon Project No. G2883-52-01 B- 1 - February 4, 2022 APPENDIX B LABORATORY TESTING We performed laboratory tests in accordance with generally accepted test methods of the American Society for Testing and Materials (ASTM) or other suggested procedures during a previous investigation in 2014. We tested selected soil samples for in-place dry density/moisture content, maximum density/optimum moisture content, expansion index, water-soluble sulfate, R-Value, unconfined compressive strength, consolidation, gradation, and direct shear strength. The results of our current laboratory tests are presented herein. The in-place dry density and moisture content of the samples tested are presented on the boring logs in Appendix A. SUMMARY OF LABORATORY MAXIMUM DRY DENSITY AND OPTIMUM MOISTURE CONTENT TEST RESULTS ASTM D 1557 Sample No. Description Maximum Dry Density (pcf) Optimum Moisture Content (% dry wt.) B1-1 Olive brown, Sandy SILT (Qpf) 115.7 15.3 B7-1 Light olive brown, Sandy SILT (Qpf) 116.6 14.5 SUMMARY OF LABORATORY EXPANSION INDEX TEST RESULTS ASTM D 4829 Sample No. Moisture Content (%) Dry Density (pcf) Expansion Index 2019 CBC Expansion Classification ASTM Soil Expansion Classification Before Test After Test B3-1 12.7 28.1 100.6 82 Expansive Medium B6-1 13.3 31.0 98.9 97 Expansive High B11-1 12.0 27.1 102.7 67 Expansive Medium SUMMARY OF LABORATORY WATER-SOLUBLE SULFATE TEST RESULTS CALIFORNIA TEST NO. 417 Sample No. Depth (feet) Geologic Unit Water-Soluble Sulfate (%) ACI 318 Sulfate Exposure B3-1 0-3 Qpf 0.034 S0 B6-1 0-5 Qpf 0.069 S0 B11-1 0-5 Qpf/To 0.035 S0 Geocon Project No. G2883-52-01 B- 2 - February 4, 2022 SUMMARY OF LABORATORY RESISTANCE VALUE (R-VALUE) TEST RESULTS ASTM D 2844 Sample No. Depth (Feet) Description (Geologic Unit) R-Value B4-1 0-5 Olive brown, Sandy CLAY (Qpf) 10 B9-1 0-5 Olive brown, Clayey SAND (Qpf) 21 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 3/8"4 PROJECT NO. G1731-11-01 U. S. STANDARD SIEVE SIZE COARSE 3"3/4"1-1/2"8 16 20 30 40 PL FINE NAT WC PE R C E N T F I N E R B Y W E I G H T (CL) Sandy CLAY0.0 PI COARSE GRAVEL G1731-11-01.GPJ B3-1 2015 BIRCH ROAD CHULA VISTA, CALIFORNIA SAND MEDIUM 5060 100 200 SAMPLE GEOCON SILT OR CLAYFINE GRAIN SIZE IN MILLIMETERS CLASSIFICATION LL 10 DEPTH (ft) OTAY RANCH TOWN CENTER ADDITION, OTAY RANCH VILLAGE 12 GRADATION CURVE Figure B-1 -2 0 2 4 6 8 10 12 14 16 180.1 1 10 100 Sample Saturated at (ksf) GEOCON G1731-11-01.GPJ Initial Dry Density (pcf) PROJECT NO. G1731-11-01 Initial Water Content (%) Initial Saturation (%)96.5 2.0 PE R C E N T C O N S O L I D A T I O N 26.0 SAMPLE NO. B2-2 CHULA VISTA, CALIFORNIA CONSOLIDATION CURVE 96.6 APPLIED PRESSURE (ksf) Figure B-2 OTAY RANCH TOWN CENTER ADDITION, OTAY RANCH VILLAGE 12 2015 BIRCH ROAD -2 0 2 4 6 8 10 12 14 16 180.1 1 10 100 Sample Saturated at (ksf) GEOCON G1731-11-01.GPJ Initial Dry Density (pcf) PROJECT NO. G1731-11-01 Initial Water Content (%) Initial Saturation (%)100+ 2.0 PE R C E N T C O N S O L I D A T I O N 23.8 SAMPLE NO. B8-3 CHULA VISTA, CALIFORNIA CONSOLIDATION CURVE 103.7 APPLIED PRESSURE (ksf) Figure B-3 OTAY RANCH TOWN CENTER ADDITION, OTAY RANCH VILLAGE 12 2015 BIRCH ROAD SAMPLE NO.: DEPTH OF SAMPLE: Load 1 K 3 K 5 K ɸ (Ultimate)21 degrees INITIAL ɸ (Peak)34 degrees Water Content 23.8%17.5%24.2%c (Ultimate)1100 psf Dry Density (pcf)96.3 95.8 99.1 c (Peak)820 psf Saturation*87.7%63.8%95.8% Height (inches)1 1 1 AFTER TEST DATE: Water Content 27.3%26.4%26.3%DESCRIPTION: Dry Density (pcf)92.4 95.6 100.3 FAILURE Normal Stress (psf)952 2080 4350 Ultimate Stress (psf)1416 1904 2702 Peak Stress (psf)1625 1964 3809 Rate (in/min)0.005 0.005 0.005 *Degree of saturation calculated with a specific gravity of 2.65 B1-2 Test Data Results 6/17/2014 Qpf 3' SW/LR DIRECT SHEAR TEST DATA OTAY RANCH TOWN CENTER ADDITION OTAY RANCH VILLAGE 12 2015 BIRCH ROAD CHULA VISTA, CALIFORNIA PROJECT NO. G1731-11-01 FIG. B-4 GEOCONI N C O R P O R A T E DGEOCONI N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121-2974 PHONE 858 558-6900 -FAX 858 558-6159 GEOCONI N C O R P O R A T E DGEOCONI N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121-2974 PHONE 858 558-6900 -FAX 858 558-6159 Natural Remold 0 1000 2000 3000 4000 5000 6000 0 1000 2000 3000 4000 5000 6000 Sh e a r S t r e s s ( p s f ) Normal Stress (psf) Ultimate Peak SAMPLE NO.: DEPTH OF SAMPLE: Load 1 K 3 K 5 K ɸ (Ultimate)28 degrees INITIAL ɸ (Peak)28 degrees Water Content 13.7%14.6%14.2%c (Ultimate)230 psf Dry Density (pcf)105.3 104.6 104.7 c (Peak)350 psf Saturation*63.7%66.3%65.0% Height (inches)1 1 1 AFTER TEST DATE: Water Content 26.9%26.2%23.6%DESCRIPTION: Dry Density (pcf)104.9 105.2 107.1 FAILURE Normal Stress (psf)952 2080 4346 Ultimate Stress (psf)728 1426 2622 Peak Stress (psf)828 1526 2672 Rate (in/min)0.005 0.005 0.005 *Degree of saturation calculated with a specific gravity of 2.65 B7-1 0' Test Data Results 6/23/2014 Qpf SW/LR DIRECT SHEAR TEST DATA OTAY RANCH TOWN CENTER ADDITION OTAY RANCH VILLAGE 12 2015 BIRCH ROAD CHULA VISTA, CALIFORNIA PROJECT NO. G1731-11-01 FIG. B-5 GEOCONI N C O R P O R A T E DGEOCONI N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121-2974 PHONE 858 558-6900 -FAX 858 558-6159 GEOCONI N C O R P O R A T E DGEOCONI N C O R P O R A T E D GEOTECHNICAL CONSULTANTS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121-2974 PHONE 858 558-6900 -FAX 858 558-6159 Natural Remold 0 1000 2000 3000 4000 5000 6000 0 1000 2000 3000 4000 5000 6000 Sh e a r S t r e s s ( p s f ) Normal Stress (psf) Ultimate Peak Geocon Project No. G2883-52-01 February 4, 2022 LIST OF REFERENCES 1. 2019 California Building Code, California Code of Regulations, Title 24, Part 2, based on the 2018 International Building Code, prepared by California Building Standards Commission, dated July 2019. 2. ACI 318-19, Commentary on Building Code Requirements for Structural Concrete, prepared by the American Concrete Institute, dated May 2019. 3. American Society of Civil Engineers (ASCE), ASCE 7-16, Minimum Design Loads and Associated Criteria for Buildings and Other Structures, 2017. 4. California Department of Conservation, Division of Mines and Geology, Probabilistic Seismic Hazard Assessment for the State of California, Open File Report 96-08, 1996. 5. County of San Diego, San Diego County Multi Jurisdiction Hazard Mitigation Plan, San Diego, California – Final Draft, dated 2017. 6. Geocon, Incorporated, Preliminary Geotechnical Investigation, Otay Ranch Town Center Addition, Otay Ranch Village 12, 2015 Birch Road, Chula Vista, California, dated June 26, 2014 (Project No. G1731-11-01). 7. Geotechnics Incorporated, As-Graded Geotechnical Report, McMillin Otay Ranch, Village 12 and Borrow and Fill Sites Within the Eastern Urban Center, Chula Vista, California, dated February 16, 2006 (Project No. 0367-012-01, Document No. 05-1029). 8. Todd, V. R., 2004, Preliminary Geologic Map of the El Cajon 30’x60’ Quadrangle, Southern California, Version 1.0, Open-File Report 2004-1361 Scale 1:100,000 9. United States Geological Survey computer program, U.S. Design Maps. USGS Design Maps. 10. United States Geological Survey (USGS) Interactive Quaternary Faults Database computer program, USGS Interactive Quaternary Faults Database. 11. Unpublished Geotechnical Reports and Information, Geocon Incorporated.