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Home My WebLink AboutParcel Map 13428 Parcel C WQMP PGPCity of Temecula WATER QUALITY MANAGEMENT PLAN (WQMP) Linfield Christian School Permit No. LD24-0469 PROJECT ADDRESS: 31950 Pauba Road, Temecula, CA 92592 PROJECT APN: 955-020-012, 955-020-018, 955-020-019 PREPARED BY: Name _KWC Engineers___________________ _Braden W. Price, PE________________ Address _1880 Compton Ave, Ste 100__________ _Corona, CA 92881__________________ Phone _(951) 734-2130 ext 230______________ Email _Braden.Price@kwcengineers.com___ PREPARED FOR: Name _Linfield Christian School____________ _Terry Cutter______________________ Address _31950 Pauba Road________________ _Temecula, CA 92592_______________ Phone _(951) 676-8111_ext 1404____________ Email _________________________________ DATE OF WQMP: July 24, 2024 APPROVED BY: APPROVAL DATE: APPROVED BY CITY OF TEMECULA PUBLIC WORKS david.pina 10/07/2024 10/07/2024 10/07/2024 10/07/20 WQMP 3 Template Date: October 31st, 2018 Preparation Date:___________ Step 1: Source Control BMP Checklist Source Control BMPs All development projects must implement source control BMPs 4.2.1 through 4.2.6 where applicable and feasible. See Chapter 4.2 and Appendix E of the City BMP Design Manual for information to implement source control BMPs shown in this checklist. Answer each category below pursuant to the following: · "Yes" means the project will implement the source control BMP as described in Chapter 4.2 and/or Appendix E of the City BMP Design Manual. Discussion / justification must be provided and show locations on the project plans. Select applicable Source Controls in the Source Control BMP summary on the following page. · "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided. · "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion / justification must be provided. Source Control Requirement Applied? 4.2.1 Prevention of Illicit Discharges into the MS4 Yes No N/A Discussion / justification: Illicit discharge into the MS4 is not anticipated for this project. 4.2.2 Storm Drain Stenciling or Signage Yes No N/A Discussion / justification: Storm drain stenciling and signage will be provided for proposed grate inlets. 4.2.3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Yes No N/A Discussion / justification: Outdoor materials storage area is not proposed for this project. 4.2.4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Yes No N/A Discussion / justification: Outdoor materials storage area is not proposed for this project. 4.2.5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Yes No N/A Discussion / justification: Trash storage area is not proposed for this project. 4.2.6 Additional BMPs Based on Potential Sources of Runoff Pollutants Yes No N/A Discussion / justification. Clearly identify which sources of runoff pollutants are discussed: Additional BMPs are not needed. 4 WQMP Preparation Date: ___________ Template Date: October 31st, 2018 Source Control BMP Summary Select all source control BMPs identified for your project in sections 4.2.1 through 4.2.6 above in the column on the left below. Then select “yes” if the BMP has been implemented and shown on the project plans, “No” if the BMP has not been implemented, or “N/A” if the BMP is not applicable to your project. SC-A. On-site storm drain inlets Yes No N/A SC-B. Interior floor drains and elevator shaft sump pumps Yes No N/A SC-C. Interior parking garages Yes No N/A SC-D1. Need for future indoor & structural pest control Yes No N/A SC-D2. Landscape/outdoor pesticide use Yes No N/A SC-E. Pools, spas, ponds, fountains, and other water features Yes No N/A SC-F. Food service Yes No N/A SC-G. Refuse areas Yes No N/A SC-H. Industrial processes Yes No N/A SC-I. Outdoor storage of equipment or materials Yes No N/A SC-J. Vehicle and equipment cleaning Yes No N/A SC-K. Vehicle/equipment repair and maintenance Yes No N/A SC-L. Fuel dispensing areas Yes No N/A SC-M. Loading docks Yes No N/A SC-N. Fire sprinkler test water Yes No N/A SC-O. Miscellaneous drain or wash water Yes No N/A SC-P. Plazas, sidewalks, and parking lots Yes No N/A SC-Q. Large trash generating facilities Yes No N/A SC-R. Animal facilities Yes No N/A SC-S. Plant nurseries and garden centers Yes No N/A SC-T. Automotive facilities Yes No N/A Note: Show all source control measures applied above on the plan sheets. WQMP 5 Template Date: October 31st, 2018 Preparation Date:___________ Step 2: Site Design BMP Checklist Site Design BMPs All development projects must implement site design BMPs SD-A through SD-H where applicable and feasible. See Chapter 4.3 and Appendix E of the City BMP Design Manual for information to implement site design BMPs shown in this checklist. Answer each category below pursuant to the following: · "Yes" means the project will implement the site design BMP as described in Chapter 4.3 and/or Appendix E of the City BMP Design Manual. Discussion / justification must be provided and show locations on the project plans. · "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion / justification must be provided. · "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project site has no existing natural areas to conserve). Discussion / justification must be provided. Site Design Requirement Applied? 4.3.1 Maintain Natural Drainage Pathways and Hydrologic Features Yes No N/A Discussion / justification: Natural drainage pathways and hydrologic features were identified and maintained. The existing site currently drains in the southwesterly direction. The proposed drainage pathways direct the flows towards the bioretention basin located adjacent to the westerly edge of the parking lot. The required volume of stormwater will be treated within the bioretention. Overflow will maintain the existing drainage pattern. 4.3.2 Conserve Natural Areas, Soils, and Vegetation Yes No N/A Discussion / justification: Natural areas within the project boundaries are unable to be conserved. The proposed site will be properly graded to make way for the new development and proposed landscaped medians placed throughout the site to maximize pervious area. 4.3.3 Minimize Impervious Area Yes No N/A Discussion / justification: Landscaped medians will be placed throughout the site to minimize impervious surface. 4.3.4 Minimize Soil Compaction Yes No N/A Discussion / justification: Soil compaction from heavy equipment will be minimized during construction as much as possible but is not be entirely preventable due to the nature of the project. 4.3.5 Impervious Area Dispersion Yes No N/A Discussion / justification: Landscaped medians are placed at the perimeter of the parking lot but runoff will be directed by the gutter. Discharging runoff from the parking lot directly into pervious areas is not possible. 4.3.6 Runoff Collection Yes No N/A Discussion / justification: Passive rainwater harvesting with the use of green roofs and permeable pavement is not feasible on this project. 6 WQMP Preparation Date: ___________ Template Date: October 31st, 2018 4.3.7 Landscaping with Native or Drought Tolerant Species Yes No N/A Discussion / justification: Landscaped medians will be planed with native or drought tolerant species. 4.3.8 Harvesting and Using Precipitation Yes No N/A Discussion / justification: Active rainwater harvesting with the use of rain barrels and cisterns is not feasible due to lack of demand. Step 3: Construction Stormwater BMP Checklist Minimum Required Standard Construction Stormwater BMPs If you answer “Yes” to any of the questions below, your project is subject to Table 1 on the following page (Minimum Required Standard Construction Stormwater BMPs). As noted in Table 1, please select at least the minimum number of required BMPs1, or as many as are feasible for your project. If no BMP is selected, an explanation must be given in the box provided. The following questions are intended to aid in determining construction BMP requirements for your project. Note: All selected BMPs below must be included on the BMP plan incorporated into the construction plan sets. 1. Will there be soil disturbing activities that will result in exposed soil areas? (This includes minor grading and trenching.) Reference Table 1 Items A, B, D, and E Note: Soil disturbances NOT considered significant include, but are not limited to, change in use, mechanical/electrical/plumbing activities, signs, temporary trailers, interior remodeling, and minor tenant improvement. Yes No 2. Will there be asphalt paving, including patching? Reference Table 1 Items D and F Yes No 3. Will there be slurries from mortar mixing, coring, or concrete saw cutting? Reference Table 1 Items D and F Yes No 4. Will there be solid wastes from concrete demolition and removal, wall construction, or form work? Reference Table 1 Items D and F Yes No 5. Will there be stockpiling (soil, compost, asphalt, concrete, solid waste) for over 24 hours? Reference Table 1 Items D and F Yes No 6. Will there be dewatering operations? Reference Table 1 Items C and D Yes No 7. Will there be temporary on-site storage of construction materials, including mortar mix, raw landscaping and soil stabilization materials, treated lumber, rebar, and plated metal fencing materials? Reference Table 1 Items E and F Yes No 8. Will trash or solid waste product be generated from this project? Reference Table 1 Item F Yes No 9. Will construction equipment be stored on site (e.g.: fuels, oils, trucks, etc.?) Reference Table 1 Item F Yes No 10. Will Portable Sanitary Services (“Porta-potty”) be used on the site? Reference Table 1 Item F Yes No 1 Minimum required BMPs are those necessary to comply with the City of Temecula Erosion and Sediment Control Ordinance (Chapter 18.18 et seq.) and the City of Temecula Engineering and Construction Manual (Chapter 18). WQMP 7 Template Date: October 31st, 2018 Preparation Date:___________ Table 1. Construction Stormwater BMP Checklist Minimum Required Best Management Practices (BMPs) CALTRANS SW Handbook2 Detail a BMP Selected Reference sheet No.’s where each selected BMP is shown on the plans. If no BMP is selected, an explanation must be provided. A. Select Erosion Control Method for Disturbed Slopes (choose at least one for the appropriate season) Vegetation Stabilization Planting3 (Summer) SS-2, SS-4 PGP Sheet 10/11 Hydraulic Stabilization Hydroseeding2 (Summer) SS-4 Bonded Fiber Matrix or Stabilized Fiber Matrix4 (Winter) SS-3 Physical Stabilization Erosion Control Blanket3 (Winter) SS-7 B. Select erosion control method for disturbed flat areas (slope < 5%) (choose at least one) Will use erosion control measures from Item A on flat areas also SS-3, 4, 7 PGP Sheet 10/11 Sediment Desilting Basin (must treat all site runoff) SC-2 Mulch, straw, wood chips, soil application SS-6, SS-8 2 State of California Department of Transportation (Caltrans). 2003. Storm Water Quality Handbooks, Construction Site Best Management Practices (BMPs) Manual. March. Available online at: http://www.dot.ca.gov/hq/construc/stormwater/manuals.htm. 3 If Vegetation Stabilization (Planting or Hydroseeding) is proposed for erosion control it may be installed between May 1st and August 15th. Slope irrigation is in place and needs to be operable for slopes >3 feet. Vegetation must be watered and established prior to October 1st. The owner must implement a contingency physical BMP by August 15th if vegetation establishment does not occur by that date. If landscaping is proposed, erosion control measures must also be used while landscaping is being established. Established vegetation must have a subsurface mat of intertwined mature roots with a uniform vegetative coverage of 70 percent of the natural vegetative coverage or more on all disturbed areas. 4 All slopes over three feet must have established vegetative cover prior to final permit approval. 8 WQMP Preparation Date: ___________ Template Date: October 31st, 2018 Table 1. Construction Stormwater BMP Checklist (continued) Minimum Required Best Management Practices (BMPs) CALTRANS SW Handbook Detail a BMP Selected Reference sheet No.’s where each selected BMP is shown on the plans. If no BMP is selected, an explanation must be provided. C. If runoff or dewatering operation is concentrated, velocity must be controlled using an energy dissipater Energy Dissipater Outlet Protection5 SS-10 Runoff/dewatering operation will not be concentrated during construction of the project. D. Select sediment control method for all disturbed areas (choose at least one) Silt Fence SC-1 PGP Sheet 10/11 Fiber Rolls (Straw Wattles) SC-5 Gravel & Sand Bags SC-6 & 8 Dewatering Filtration NS-2 Storm Drain Inlet Protection SC-10 Engineered Desilting Basin (sized for 10-year flow) SC-2 E. Select method for preventing offsite tracking of sediment (choose at least one) Stabilized Construction Entrance TC-1 PGP Sheet 10/11 Construction Road Stabilization TC-2 Entrance/Exit Tire Wash TC-3 Entrance/Exit Inspection & Cleaning Facility TC-1 Street Sweeping and Vacuuming SC-7 F. Select the general site management BMPs F.1 Materials Management Material Delivery & Storage WM-1 PGP Sheet 10/11 Spill Prevention and Control WM-4 F.2 Waste Management6 Waste Management Concrete Waste Management WM-8 PGP Sheet 10/11 Solid Waste Management WM-5 Sanitary Waste Management WM-9 Hazardous Waste Management WM-6 Note: The Construction General Permit (Order No. 2009-0009-DWQ) also requires all projects not subject to the BMP Design Manual to comply with runoff reduction requirements through the implementation of post-construction BMPs as described in Section XIII of the order. 5 Regional Standard Drawing D-40 – Rip Rap Energy Dissipater is also acceptable for velocity reduction. 6 Not all projects will have every waste identified. The applicant is responsible for identifying wastes that will be onsite and applying the appropriate BMP. For example, if concrete will be used, BMP WM-8 must be selected. WQMP 9 Template Date: October 31st, 2018 Preparation Date:___________ Step 4: Project type determination (Standard or Priority Development Project) Is the project part of another Priority Development Project (PDP)? Yes No If so, Standard and PDP requirements apply. Go to Step 4.1 and select “PDP” The project is (select one): ☐ New Development Redevelopment7 The total proposed newly created or replaced impervious area is: _____60,332____ ft2 The total existing (pre-project) impervious area is: ______2,645____ ft2 The total area disturbed by the project is: _____152,324___ ft2 If the total area disturbed by the project is 1 acre (43,560 sq. ft.) or more OR the project is part of a larger common plan of development disturbing 1 acre or more, a Waste Discharger Identification (WDID) number must be obtained from the State Water Resources Control Board. WDID: _____933C403964______ Is the project in any of the following categories, (a) through (f)?8 Yes No (a) New development projects that create 10,000 square feet or more of impervious surfaces 9(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 projects that create and/or replace 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 and redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface (collectively over the entire project site), and support one or more of the following uses: (i) Restaurants. 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 (SIC) 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. 7 Redevelopment is defined as: The creation and/or replacement of impervious surface on an already developed site. Examples include the expansion of a building footprint, road widening, the addition to or replacement of a structure, and creation or addition of impervious surfaces. Replacement of impervious surfaces includes any activity that is not part of a routine maintenance activity where impervious material(s) are removed, exposing underlying soil during construction. Redevelopment does not include routine maintenance activities, such as trenching and resurfacing associated with utility work; pavement grinding; resurfacing existing roadways; new sidewalks construction; pedestrian ramps; or bike lanes on existing roads; and routine replacement of damaged pavement, such as pothole repair. 8 Applicants should note that any development project that will create and/or replace 10,000 square feet or more of impervious surface (collectively over the entire project site) is considered a new development. 10 WQMP Preparation Date: ___________ Template Date: October 31st, 2018 Project type determination (continued) Yes No (d) New or redevelopment projects that create and/or replace 2,500 square feet or more of impervious surface (collectively over the entire project site), and discharging directly to an Environmentally Sensitive Area (ESA). “Discharging directly to” includes flow that is conveyed overland a distance of 200 feet or less from the project to 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). Note: ESAs are areas that include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Board and San Diego Water Board; State Water Quality Protected Areas; water bodies designated with the RARE beneficial use by the State Water Board and San Diego Water Board; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. See BMP Design Manual Chapter 1.4.2 for additional guidance. Yes No (e) New development projects, or redevelopment projects that create and/or replace 5,000 square feet or more of impervious surface, that support one or more of the following uses: (i) Automotive repair shops. This category is defined as a facility that is categorized in any one of the following SIC codes: 5013, 5014, 5541, 7532-7534, or 7536- 7539. (ii) Retail gasoline outlets (RGOs). This category includes RGOs that meet 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. Yes No (f) New or redevelopment projects that result in the disturbance of one or more acres of land and are expected to generate pollutants post construction. Note: See BMP Design Manual Chapter 1.4.2 for additional guidance. Does the project meet the definition of one or more of the Priority Development Project categories (a) through (f) listed above? ☐ No – the project is not a Priority Development Project (Standard Project). Yes – the project is a Priority Development Project (PDP). Further guidance may be found in Chapter 1 and Table 1-2 of the BMP Design Manual. The following is for redevelopment PDPs only: The area of existing (pre-project) impervious area at the project site is: _____2,645_____ ft2 (A) The total proposed newly created or replaced impervious area is ____ 60,332 ____ ft2 (B) Percent impervious surface created or replaced (B/A)*100: ______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 newly created or replaced impervious areas are considered a PDP and subject to stormwater requirements OR greater than fifty percent (50%) – the entire project site is considered a PDP and subject to stormwater requirements WQMP 11 Template Date: October 31st, 2018 Preparation Date:___________ Step 4.1: Water Quality Management Plan requirements Step Answer Progression Is the project a Standard Project, Priority Development Project (PDP), or exception to PDP definitions? To answer this item, complete Step 4 Project Type Determination Checklist, and see PDP exemption information below. For further guidance, see Chapter 1.4 of the BMP Design Manual in its entirety. Standard Project Standard Project requirements apply, STOP, you have satisfied stormwater requirements. PDP Standard and PDP requirements apply. Complete Exhibit A “PDP Requirements.” http://temeculaca.gov/wqmpa2 PDP Exemption Go to Step 4.2 below. Step 4.2: Exemption to PDP definitions Is the project exempt from PDP definitions based on either of the following: Projects that are only new or retrofit paved sidewalks, bicycle lanes, or trails that meet the following criteria: (i) Designed and constructed to direct stormwater runoff to adjacent vegetated areas, or other non-erodible permeable areas; OR (ii) Designed and constructed to be hydraulically disconnected from paved streets or roads [i.e., runoff from the new improvement does not drain directly onto paved streets or roads]; OR (iii) Designed and constructed with permeable pavements or surfaces in accordance with City of Temecula Guidance on Green Infrastructure; If so: Standard Project requirements apply, AND any additional requirements specific to the type of project. City concurrence with the exemption is required. Provide discussion and list any additional requirements below in this form. STOP, you have satisfied stormwater requirements. Projects that are only retrofitting or redeveloping existing paved alleys, streets or roads that are designed and constructed in accordance with the City of Temecula Guidance on Green Infrastructure. Complete Exhibit A “PDP Requirements.” Select Green Streets Exemptions where applicable. Discussion / justification, and additional requirements for exceptions to PDP definitions, if applicable: Exhibit A City of Temecula PRIORITY DEVELOPMENT PROJECT REQUIREMENTS ii PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Preparer's Certification Page Project Name: _Linfield Christian School___________ Permit Application Number: _LD24-0469_____________________ PREPARER'S CERTIFICATION I hereby declare that I am the Engineer in Responsible Charge of design of Stormwater best management practices (BMPs) for this project, and that I have exercised responsible charge over the design of the BMPs as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with the PDP requirements of the City of Temecula BMP Design Manual, which is a design manual for compliance with local City of Temecula Stormwater and Urban Runoff Management and Discharge Controls Ordinance (Chapter 8.28 et seq.) and regional MS4 Permit (California Regional Water Quality Control Board San Diego Region Order No. R9-2013-0001 as amended by R9-2015-0001 and R9-2015-0100) requirements for stormwater management. I have read and understand that the City of Temecula has adopted minimum requirements for managing urban runoff, including stormwater, from land development activities, as described in the BMP Design Manual. I certify that this PDP WQMP has been completed to the best of my ability and accurately reflects the project being proposed and the applicable BMPs proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I understand and acknowledge that the plan check review of this PDP WQMP by City staff is confined to a review and does not relieve me, as the Engineer in Responsible Charge of design of stormwater BMPs for this project, of my responsibilities for project design. 95136 09/30/2025 Engineer of Work's Signature, PE Number & Expiration Date Braden W. Price, PE Print Name KWC Engineers (951) 734-2130 ext 230 Company & Phone No. _____________________________ Date Engineer's Seal: 07/25/2024 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 3 Template Date: August 14th, 2022 Preparation Date:________________ Step 1: Site Information Checklist Description of Existing Site Condition and Drainage Patterns Project Watershed (Complete Hydrologic Unit, Area, and Subarea Name with Numeric Identifier; e.g., 902.52 Santa Margarita HU, Pechanga HA, Wolf HSA) 902.32 Santa Margarita HU, Murrieta HA, undefined HSA Current Status of the Site (select all that apply): Existing development Previously graded but not built out Demolition completed without new construction Agricultural or other non-impervious use Vacant, undeveloped/natural Description / Additional Information: The site is currently vacant with a portion dedicated to an existing maintenance yard to the east. The site is bounded by open space to the north and Linfield Christian School to the south. Existing Land Cover Includes (select all that apply and provide each area on site): Pervious Area 3.44 Acres (149,679 Square Feet) Impervious Areas 0.06 Acres (2,645 Square Feet) Description / Additional Information: The site is primarily vacant with an existing maintenance yard on the east side. How is stormwater runoff conveyed from the site? At a minimum, this description should answer: (1) Whether existing drainage conveyance is natural or urban; (2) Is runoff from offsite conveyed through the site? If yes, describe the offsite drainage areas, design flows, and locations where offsite flows enter the project site, and summarize how such flows are conveyed through the site; (3) Provide details regarding existing project site drainage conveyance network, including any existing storm drains, concrete channels, swales, detention facilities, stormwater treatment facilities, natural or constructed channels; and (4) Identify all discharge locations from the existing project site along with a summary of conveyance system size and capacity for each of the discharge locations. Provide summary of the pre-project drainage areas and design flows to each of the existing runoff discharge locations. Reference the Drainage report Attachment for detailed calculations. Describe existing site drainage patterns: In its existing condition, natural runoff from the site sheet flows from north to south and is collected in a set of grate inlets located southeast and southwest of the site. These inlets connect to a storm drain system that conveys stormwater to an existing pond within the school, to the south of the proposed parking lot improvements. 4 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Description of Proposed Site Development and Drainage Patterns Project Description / Proposed Land Use and/or Activities: This project proposes to construct a maintenance building and expand the parking lot. Solar panel canopies will also be installed in the parking lot and maintenance yard. Solar canopies are pervious and will allow rainfall through them to the ground below. Proposed Land Cover Includes (select all that apply and provide each area on site): Existing to Remain Pervious Area _______ Acres (_______ Square Feet) Impervious Areas _______ Acres (_______ Square Feet) Existing to Be Replaced Pervious Area __2.30_____ Acres (100,147 Square Feet) Impervious Areas ___0.04____ Acres (1,786 Square Feet) Newly Created Pervious Area _0.02__ Acres (888 Square Feet) Impervious Areas __1.14_ Acres (49,503 Square Feet) Total Pervious Area 2.32 Acres (101,035 Square Feet) Impervious Areas 1.18 Acres (51,289 Square Feet) Description / Additional Information: Solar panels in the parking lot will be installed within the landscaped medians. The solar panels will not act as a canopy as they are pervious, thus the landscaped area underneath the canopy is counted toward the site’s pervious area. List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): Proposed improvements include a paved parking lot, future maintenance building, and access road. List/describe proposed pervious features of the project (e.g., landscape areas): Landscaped medians and landscaped areas will be incorporated throughout the site. DG and CAB areas are also included adjacent to parking and within the maintenance yard. Describe any grading or changes to site topography: The overall drainage of the site will remain consistent with the existing condition. Provide details regarding the proposed project site drainage conveyance network, including storm drains, concrete channels, swales, detention facilities, stormwater treatment facilities, natural or constructed channels, and the method for conveying offsite flows through or around the proposed project site. Identify all discharge locations from the proposed project site along with a summary of the conveyance system size and capacity for each of the discharge locations. Provide a summary of pre- and post-project drainage areas and design flows to each of the runoff discharge locations. Reference the drainage study for detailed calculations. Describe proposed site drainage patterns: Runoff from the parking lot will surface flow across the parking lot and be directed via gutters and ribbon gutters to inlets that will then be piped into the proposed BMP on the west. In the maintenance yard, all flows sheet flow to inlets throughout the yard. These inlets drain to the proposed BMP on the south side of the yard. PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 5 Template Date: August 14th, 2022 Preparation Date:________________ Description of Receiving Water(s) and Pollutants of Concern Describe flow path of stormwater from the project site discharge location(s), through urban storm conveyance systems as applicable, to receiving creeks, rivers, and lagoons as applicable, and ultimate discharge to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): Runoff from this project is tributary to Long Canyon Creek. Long Canyon Creek drains to Murrieta Creek and Santa Margarita River, ultimately discharging into the Pacific Ocean. List any 303(d) impaired water bodies1 within the path of stormwater from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs and/or Highest Priority Pollutants from the WQIP for the impaired water bodies (see BMP Design Manual Appendix B.6.1): 303(d) Impaired Water Body Pollutant(s)/Stressor(s) TMDLs / WQIP Highest Priority Pollutant Long Canyon Creek Chlorpyrifos, Iron, Manganese, Nitrogen, Phosphorus Chlorpyrifos, Iron, Manganese, Nitrogen, Phosphorus Murrieta Creek Benthic Community Effects, Bifenthrin, Chlorpyrifos, Copper, Cyhalothrin, Lambda, Indicator Bacteria, Iron, Manganese, Mercury, Nitrogen, Oxygen, Dissolved, Phosphorus, Pyrethroids, Toxicity, Turbidity Benthic Community Effects, Bifenthrin, Chlorpyrifos, Copper, Cyhalothrin, Lambda, Indicator Bacteria, Iron, Manganese, Mercury, Nitrogen, Oxygen, Dissolved, Phosphorus, Pyrethroids, Toxicity, Turbidity Santa Margarita River (Upper) Benthic Community Effects, Bifenthrin, Cyhalothrin Lambda, Indicator Bacteria, Iron, Manganese, Nitrogen, Phosphorus, Pyrethroids, Total Dissolved Solids, Toxicity, Turbidity Benthic Community Effects, Bifenthrin, Cyhalothrin Lambda, Indicator Bacteria, Iron, Manganese, Nitrogen, Phosphorus, Pyrethroids, Total Dissolved Solids, Toxicity, Turbidity Santa Margarita River (Lower) Benthic Community Effects, Chlorpyrifos, Indicator Bacteria, Nitrogen, Phosphorus, Toxicity Benthic Community Effects, Chlorpyrifos, Indicator Bacteria, Nitrogen, Phosphorus, Toxicity 1 The current list of Section 303(d) impaired water bodies can be found at http://www.waterboards.ca.gov/water_issues/programs/water_quality_assessment/#impaired 6 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Identify pollutants expected from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6.): Pollutant Not Applicable to the Project Site Anticipated from the Project Site Also a Receiving Water Pollutant of Concern Sediment Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding Substances Oil & Grease Bacteria & Viruses Pesticides Site Requirements and Constraints The following is for redevelopment PDPs only: The area of existing (pre-project) impervious area at the project site is: _____2,645_____ ft2 (A) The total proposed newly created or replaced impervious area is ____ 60,332_____ ft2 (B) Percent impervious surface created or replaced (B/A)*100: _____ 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 newly created or replaced impervious areas are considered a PDP and subject to stormwater requirements OR greater than fifty percent (50%) – the entire project site is considered a PDP and subject to stormwater requirements List applicable site requirements or constraints that will influence stormwater management design, such as zoning requirements including setbacks and open space, or local codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements: N/A Optional Additional Information or Continuation of Previous Sections As Needed PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 7 Template Date: August 14th, 2022 Preparation Date:________________ This space provided for additional information or continuation of information from previous sections as needed. 8 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Step 2: Strategy for Meeting PDP Performance Requirements PDPs must implement BMPs to control pollutants in stormwater that may be discharged from a project (see Chapter 5). PDPs subject to hydromodification management requirements must implement flow control BMPs to manage hydromodification (see Chapter 6). Both stormwater pollutant control and flow control can be achieved within the same BMP(s). Projects triggering the 50% rule must address stormwater requirements for the entire site. Structural BMPs must be verified by the City at the completion of construction. This may include requiring the project owner or project owner's representative and engineer of record to certify construction of the structural BMPs (see Chapter 1.12). Structural BMPs must be maintained into perpetuity, and the City must confirm the maintenance (see Chapter 7). Provide a narrative description of the general strategy for pollutant control and flow control at the project site in the box below. This information must describe how the steps for selecting and designing stormwater pollutant control BMPs presented in Chapter 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated or separate. At the end of this discussion, provide a summary of all the BMPs within the project including the type and number. Describe the general strategy for BMP implementation at the site. The overall drainage of the site is consistent with the existing condition. Runoff from the parking lot will drain towards the south across the parking lot and be captured by the curb and gutter that will direct the flows into a drop inlet. The flows will then enter into the storm drain system. From there, it will discharge into the proposed basin located on the west side of the project site following a series of gutters. Runoff from the storage yard drain south towards a basin. The overflow runoffs may contain fertilizers, but they will be treated for prior to discharging. Offsite flow from existing storm drains along Pauba Road will still be received on the natural channel southwest of the site. PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 9 Template Date: August 14th, 2022 Preparation Date:________________ ATTACHMENT 1 STORMWATER POLLUTANT CONTROL BMP SELECTION Indicate which Items are Included behind this cover sheet: Attachment Sequence Contents Checklist Special Considerations for Redevelopment Projects (50% Rule) see chapter 1.7 and Step 1.3 Less than or equal to fifty percent (50%) Greater than fifty percent (50%) Refer to Figure 5-1: Stormwater Pollutant Control BMP Selection Flow Chart Attachment 1a DMA Exhibit (Required) See DMA Exhibit Checklist on the back of this form. See Chapter 3.3.3 for guidance Included Entire project is designed with Self-Mitigating and De-Minimis DMAs. The project is compliant with Pollution Control BMP sizing requirements. STOP * Attachment 1b Figure B.1-1: 85th Percentile 24-hour Isohyetal Map with project location Included Attachment 1c Worksheet B.3-1 Structural BMP Feasibility: Project-Scale BMP Feasibility Analysis Included Attachment 1d Worksheet B.2-1 DCV 2 Included Attachment 1e Applicable Site Design BMP Fact Sheet(s) from Appendix E Included Entire project is designed with Self-Retaining DMAs. The project is compliant with Pollution Control BMP sizing requirements. STOP * Attachment 1f Structural BMP Inventory Included Attachment 1g Structural Pollutant Control BMP Checklist for each Structural BMP Included Attachment 1h Is Onsite Alternative Compliance proposed?3 No Yes - Include WQE worksheets Attachment 1i Offsite Alternative Compliance Participation Form - Pollutant Control Refer to Figure 1-3:Pathways to Participating in Offsite Alternative Compliance Program Full Compliance Onsite Partial Compliance Onsite with Offsite Alternative Compliance or Full Offsite Alternative Compliance. Document onsite structural BMPs and complete - Pollutant Control Offsite Alternative Compliance Participation Form, and - WQE worksheets * If this box is checked, the remainder of Attachment 1 does not need to be filled out. 2 All stormwater pollutant control worksheets have been automated and are available for download at: https://www.sandiegocounty.gov/content/sdc/dpw/watersheds/DevelopmentandConstruction/BMP_Design_Manual. html 3 Water Quality Equivalency Guidance and automated worksheets for Region 9: http://www.projectcleanwater.org/water-quality-equivalency-guidance/ Attachment 1A SITE PLAN EXHIBIT 10 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 1a: DMA Exhibit Checklist See Chapter 3.3.3 for guidance Point(s) of Compliance Project Site Boundary Project Disturbed Area Footprint Drainage management area (DMA) boundaries, DMA ID numbers, DMA areas (square footage or acreage), DMA land use and pollutants of concern, and DMA type (i.e., drains to structural BMP, self-retaining, self-mitigating, or de-minimis) Note on exhibit de-minimis areas and discuss reason they could not be included in Step 1.3 per section 5.2.2 of the manual. Include offsite areas receiving treatment to mitigate Onsite Water Quality Equivalency. Include summary table of worksheet inputs for each DMA. Include description of self-mitigating areas. Potential pollutant source areas and corresponding required source control BMPs (see Chapter 4, Appendix E.1, and Step 3.5) Proposed Site Design BMPs and surface treatments used to minimize imperviousness. Show sections, details, and dimensions of site design BMP’s per chapter 5.2.3 (tree wells, dispersion areas, rain gardens, permeable pavement, rain barrels, green roofs, etc.) Proposed Harvest and Use BMPs Underlying hydrologic soil group (Web Soil Survey) Existing natural hydrologic features (watercourses, seeps, springs, wetlands, pond, lake) Existing topography and impervious areas Proposed grading and impervious areas. If the project is a subdivision or spans multiple lots show pervious and impervious totals for each lot. Existing and proposed site drainage network and connections to drainage offsite Potable water wells, onsite wastewater treatment systems (septic), underground utilities Structural BMPs (identify location, structural BMP ID No., type of BMP, and size/detail) Approximate depth to groundwater at each structural BMP Approximate infiltration rate and feasibility (full retention, partial retention, biofiltration) at each structural BMP Critical coarse sediment yield areas to be protected and or conveyed through the project site, if applicable. Temporary Construction BMPs. Include protection of source control, site design and structural BMPs during construction. D D U U EV P A R K I N G ONL Y EV P A R K I N G O N L Y EV P A R K I N G ON L Y EV P A R K I N G ON L Y EV P A R K I N G ON L Y EV P A R K I N G ONL Y EV PARKING ONLY EV PARKING ONLY EV P A R K I N G O N L Y BASIN A - BIORETENTION BASIN DESIGN VOL = 3,795 CU-FT PROP VOL= 5,186 CU-FT FOOTPRINT= 2,412 SQ-FT GROUNDWATER DEPTH = >20' INFILTRATION RATE ~ 0.15"/HR BASIN B - BIORETENTION BASIN DESIGN VOL = 2,205 CU-FT PROP VOL= 3,717 CU-FT FOOTPRINT= 2,094 SQ-FT GROUNDWATER DEPTH = >20' INFILTRATION RATE ~ 0.15"/HR SOLAR PANELS SOLAR PANELS SOLAR PANELS FUTURE MAINTENANCE BUILDING EXISTING TECH SUPPORT CENTER DMA B 1.45 DMA A 2.05 D.G. TRAIL D.G. TRAIL EXISTING LAKE POC A POC B 16 . 8 4 T G 13 . 8 4 I N V . 17 . 3 2 T G 14 . 3 2 I N V . 23.7 TG 20.70 INV 08.50 TG 03.50 INV (1199.30) INV (11.22 INV) 17.9 TG 14.98 INV. 17.6 TG 15.34 INV. 17 . 7 T G 15 . 7 0 I N V . 15.00 TG 11.50 INV 17.2 TG 15.40 INV. 17.0 TG 14.0 INV. 12.26 TG 09.26 INV. 14.26 TG 11.26 INV. (10.7) INV. 08.00 INV. 14.50 INV. 14.50 INV. LEGEND TRIBUTARY AREA BOUNDARY DMA NUMBER TRIBUTARY AREA (ACRES) DRAINAGE FLOW DIRECTION RIDGE LINE LANDSCAPING AREA DMA A 0.41 A WQMP TREATMENT SUMMARY TABLE DMA IMPERVIOUS (AC) PERVIOUS (AC) DESIGN CAPTURE VOLUME (CU-FT) PROPOSED CAPTURE VOLUME (CU-FT) PROPOSED WQMP BASIN B STREET AREA DMA AREA (AC) 0.99 1.06 3,795 5,1862.05 0.40 1.05 2,205 3,7171.45 TOTAL 1.39 2.11 --3.50 ROOF AREA DESIGN FLOW RATE (CFS) PROPOSED FLOW RATE (CFS) -- -- -- DECOMPOSED GRANITE CLASS 2 BASE SOIL GROUP: A & C BMP BASIN B - BASIN A Attachment 1B 85TH PERCENTILE 24-HOUR ISOHYETAL MAP WITH PROJECT LOCATION RIVERSIDE COUNTY FLOOD CONTROL AND WATER CONSERVATION DISTRICT Isohyetal Map for the 85th Percentile 24 hour Storm Event July 2011 Rain Gage Locations Project Site 1.00" Attachment 1C WORKSHEET B.3-1 Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods B-9 July 2018 B.3 Structural BMP Feasibility The purpose of this section is to determine the BMP types that are acceptable for implementation at the project site. Through completion of Worksheet B.3-1 (see Appendix I), applicants will evaluate the feasibility of harvest & use, full retention, and partial retention BMPs at their project site. Worksheet B.3-1. Project-Scale BMP Feasibility Analysis Category # Description Value Units Capture & Use Inputs 0 Design Capture Volume for Entire Project Site cubic-feet 1 Proposed Development Type unitless 2 Number of Residents or Employees at Proposed Development # 3 Total Planted Area within Development sq-ft 4 Water Use Category for Proposed Planted Areas unitless Infiltration Inputs 5 Is Average Site Infiltration Rate Less than 0.5 Inches per Hour? yes/no 6 Is Retention of the Full DCV Anticipated to Produce Negative Impacts? yes/no 7 Is Retention of Any Volume Anticipated to Produce Negative Impacts? yes/no Calculations 8 36-Hour Toilet Use Per Resident or Employee cubic-feet 9 Subtotal: Anticipated 36 Hour Toilet Use cubic-feet 10 Anticipated 1 Acre Landscape Use Over 36 Hours cubic-feet 11 Subtotal: Anticipated Landscape Use Over 36 Hours cubic-feet 12 Total Anticipated Use Over 36 Hours cubic-feet 13 Total Anticipated Use / Design Capture Volume cubic-feet 14 Are Full Capture and Use Techniques Feasible for this Project? unitless 15 Is Full Retention Feasible for this Project? yes/no 16 Is Partial Retention Feasible for this Project? yes/no Result 17 Feasibility Category 1, 2, 3, 4, 5 Worksheet B.3-1 General Notes: A. Applicants may use this optional worksheet to determine the feasibility of implementing capture and use techniques on their project site. Applicants should provide inputs for yellow shaded cells and calculate appropriate values for unshaded cells. Projects demonstrating feasibility or potential feasibility via this worksheet are encouraged to incorporate capture and use features in their project. An automated version of this worksheet developed by the County of San Diego is included in Appendix I. B. Negative impacts associated with retention may include geotechnical, groundwater, water balance, or other issues identified by a geotechnical engineer and substantiated through completion of Form I-8 included in Appendix A.2. C. Feasibility Category 1: Applicant must implement capture & use, retention, and/or infiltration elements for the entire DCV. D. Feasibility Category 2: Applicant must implement capture & use elements for the entire DCV. E. Feasibility Category 3: Applicant must implement retention and/or infiltration elements for the entire DCV. F. Feasibility Category 4: Applicant must implement partial retention BMPs. G. Feasibility Category 5: Applicant must implement biofiltration BMPs. H. PDPs participating in an offsite alternative compliance program are not held to the feasibility categories presented herein. 6,000 Parking Lot 100 Moderate YES 3 No NA NA NA NA NA NA No No NA NA 49,412 Attachment 1D WORKSHEET B.2-1 DCV Category # Description i ii iii iv v vi vii viii ix x Units 0 Drainage Basin ID or Name A B unitless 1 Basin Drains to the Following BMP Type Retention Retention unitless 2 85th Percentile 24-hr Storm Depth 1.00 1.00 inches 3 Design Infiltration Rate Recommended by Geotechnical Engineer 5.000 5.000 in/hr 4 Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 43,056 17,276 sq-ft 5 Semi-Pervious Surfaces Not Serving as Dispersion Area (C=0.30) 11,412 31,148 sq-ft 6 Engineered Pervious Surfaces Not Serving as Dispersion Area (C=0.10) 34,825 14,587 sq-ft 7 Natural Type A Soil Not Serving as Dispersion Area (C=0.10) 0 0 sq-ft 8 Natural Type B Soil Not Serving as Dispersion Area (C=0.14) 0 0 sq-ft 9 Natural Type C Soil Not Serving as Dispersion Area (C=0.23) 0 0 sq-ft 10 Natural Type D Soil Not Serving as Dispersion Area (C=0.30) 0 0 sq-ft 11 Does Tributary Incorporate Dispersion, Tree Wells, and/or Rain Barrels? No No No No No No No No No No yes/no 12 Impervious Surfaces Directed to Dispersion Area per SD-B (Ci=0.90) sq-ft 13 Semi-Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft 14 Engineered Pervious Surfaces Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft 15 Natural Type A Soil Serving as Dispersion Area per SD-B (Ci=0.10) sq-ft 16 Natural Type B Soil Serving as Dispersion Area per SD-B (Ci=0.14) sq-ft 17 Natural Type C Soil Serving as Dispersion Area per SD-B (Ci=0.23) sq-ft 18 Natural Type D Soil Serving as Dispersion Area per SD-B (Ci=0.30) sq-ft 19 Number of Tree Wells Proposed per SD-A # 20 Average Mature Tree Canopy Diameter ft 21 Number of Rain Barrels Proposed per SD-E # 22 Average Rain Barrel Size gal 23 Does BMP Overflow to Stormwater Features in Downstream Drainage? No No No No No No No No No No unitless 24 Identify Downstream Drainage Basin Providing Treatment in Series unitless 25 Percent of Upstream Flows Directed to Downstream Dispersion Areas percent 26 Upstream Impervious Surfaces Directed to Dispersion Area (Ci=0.90) 0 0 0 0 0 0 0 0 0 0 cubic-feet 27 Upstream Impervious Surfaces Not Directed to Dispersion Area (C=0.90) 0 0 0 0 0 0 0 0 0 0 cubic-feet 28 Total Tributary Area 89,293 63,011 0 0 0 0 0 0 0 0 sq-ft 29 Initial Runoff Factor for Standard Drainage Areas 0.51 0.42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 30 Initial Runoff Factor for Dispersed & Dispersion Areas 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 31 Initial Weighted Runoff Factor 0.51 0.42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 32 Initial Design Capture Volume 3,795 2,205 0 0 0 0 0 0 0 0 cubic-feet 33 Total Impervious Area Dispersed to Pervious Surface 0 0 0 0 0 0 0 0 0 0 sq-ft 34 Total Pervious Dispersion Area 0 0 0 0 0 0 0 0 0 0 sq-ft 35 Ratio of Dispersed Impervious Area to Pervious Dispersion Area n/a n/a n/a n/a n/a n/a n/a n/a n/a n/a ratio 36 Adjustment Factor for Dispersed & Dispersion Areas 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 1.00 ratio 37 Runoff Factor After Dispersion Techniques 0.51 0.42 n/a n/a n/a n/a n/a n/a n/a n/a unitless 38 Design Capture Volume After Dispersion Techniques 3,795 2,205 0 0 0 0 0 0 0 0 cubic-feet 39 Total Tree Well Volume Reduction 0 0 0 0 0 0 0 0 0 0 cubic-feet 40 Total Rain Barrel Volume Reduction 0 0 0 0 0 0 0 0 0 0 cubic-feet 41 Final Adjusted Runoff Factor 0.51 0.42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 unitless 42 Final Effective Tributary Area 45,539 26,465 0 0 0 0 0 0 0 0 sq-ft 43 Initial Design Capture Volume Retained by Site Design Elements 0 0 0 0 0 0 0 0 0 0 cubic-feet 44 Final Design Capture Volume Tributary to BMP 3,795 2,205 0 0 0 0 0 0 0 0 cubic-feet Worksheet B.1-1 General Notes: False False False Automated Worksheet B.1-1: Calculation of Design Capture Volume (V1.3) A. Applicants may use this worksheet to calculate design capture volumes for up to 10 drainage areas User input must be provided for yellow shaded cells, values for all other cells will be automatically generated, errors/notifications will be highlighted in red and summarized below. Upon completion of this worksheet, proceed to the appropriate BMP Sizing worksheet(s). Dispersion Area, Tree Well & Rain Barrel Inputs (Optional) Standard Drainage Basin Inputs Results Tree & Barrel Adjustments Initial Runoff Factor Calculation Dispersion Area Adjustments Treatment Train Inputs & Calculations False Attachment 1E APPLICABLE SITE DESIGN BMP FACT SHEETS INF-2 Bioretention www.sandiegocounty.gov/stormwater E-69 Effective September 15, 2020 E.10 INF-2 Bioretention Photo Credit: Ventura County Technical Guidance Document Description Bioretention (bioretention without underdrain) facilities are vegetated surface water systems that filter water through vegetation and soil, or engineered media prior to infiltrating into native soils. These facilities are designed to infiltrate the full DCV. Bioretention facilities are commonly incorporated into the site within parking lot landscaping, along roadsides, and in open spaces. They can be constructed inground or partially aboveground, such as planter boxes with open bottoms (no impermeable liner at the bottom) to allow infiltration. Treatment is achieved through filtration, sedimentation, sorption, infiltration, biochemical processes and plant uptake. Typical bioretention without underdrain components include: • Inflow distribution mechanisms (e.g, perimeter flow spreader or filter strips) • Energy dissipation mechanism for concentrated inflows (e.g., splash blocks or riprap) • Shallow surface ponding for captured flows • Side slope and basin bottom vegetation selected based on expected climate and ponding depth • Non-floating mulch layer • Media layer (planting mix or engineered media) capable of supporting vegetation growth • Filter course layer consisting of aggregate to prevent the migration of fines into uncompacted native soils or the optional aggregate storage layer • Optional aggregate storage layer for additional infiltration storage • Uncompacted native soils at the bottom of the facility • Overflow structure MS4 Permit Category Retention Manual Category Infiltration Applicable Performance Standard Pollutant Control Flow Control Primary Benefits Volume Reduction Treatment Peak Flow Attenuation INF-2 Bioretention www.sandiegocounty.gov/stormwater E-70 Effective September 15, 2020 Design Adaptations for Project Goals • Full infiltration BMP for storm water pollutant control. Bioretention can be used as a pollutant control BMP designed to infiltrate runoff from direct rainfall as well as runoff from adjacent tributary areas. Bioretention facilities must be designed with an infiltration storage volume (a function of the ponding, media and aggregate storage volumes) equal to the full DCV and able to meet drawdown time limitations. • Integrated storm water flow control and pollutant control configuration. Bioretention facilities can be designed to provide flow rate and duration control. This may be accomplished by providing greater infiltration storage with increased surface ponding and/or aggregate storage volume for storm water flow control. INF-2 Bioretention www.sandiegocounty.gov/stormwater E-71 Effective September 15, 2020 Typical plan and section view of a Bioretention BMP Recommended Siting Criteria Bioretention must meet the following design criteria. Deviations from the below criteria may be approved at the discretion of County staff if it is determined to be appropriate: INF-2 Bioretention www.sandiegocounty.gov/stormwater E-72 Effective September 15, 2020 Siting Criteria Intent/Rationale □ Placement observes geotechnical recommendations regarding potential hazards (e.g., slope stability, landslides, liquefaction zones) and setbacks (e.g., slopes, foundations, utilities). Must not negatively impact existing site geotechnical concerns. □ Selection and design of BMP is based on infiltration feasibility criteria and appropriate design infiltration rate presented in Appendix B and D. Must operate as a full infiltration design and must be supported by drainage area and in-situ infiltration rate feasibility findings. □ Contributing tributary area is ≤ 5 acres (≤ 1 acre preferred). Bigger BMPs require additional design features for proper performance. Contributing tributary area greater than 5 acres may be allowed at the discretion of County staff if the following conditions are met: 1) incorporate design features (e.g. flow spreaders) to minimize short circuiting of flows in the BMP and 2) incorporate additional design features requested by County staff for proper performance of the regional BMP. □ Finish grade of the facility is ≤ 2%. In long bioretention facilities where the potential for internal erosion and channelization exists, the use of check dams is required. Flatter surfaces reduce erosion and channelization within the facility. Internal check dams reduce velocity and dissipate energy. Design Criteria and Considerations Bioretention must meet the following design criteria. Deviations from the below criteria may be approved at the discretion of County staff if it is determined to be appropriate: Siting and Design Intent/Rationale Surface Ponding □ Surface ponding is limited to a 24-hour drawdown time. 24-hour drawdown time is recommended for plant health. Surface ponding drawdown time greater than 24-hours but less than 96 hours may be allowed at the discretion of County staff if certified by a landscape architect or agronomist. X X X X X INF-2 Bioretention www.sandiegocounty.gov/stormwater E-73 Effective September 15, 2020 Siting and Design Intent/Rationale □ Surface ponding depth is ≥ 6 and ≤ 12 inches. Surface ponding capacity lowers subsurface storage requirements. Deep surface ponding raises safety concerns. Surface ponding depth greater than 12 inches (for additional pollutant control or surface outlet structures or flow- control orifices) may be allowed at the discretion of County staff if the following conditions are met: 1) surface ponding depth drawdown time is less than 24 hours; and 2) safety issues and fencing requirements are considered (typically ponding greater than 18” will require a fence and/or flatter side slopes) and 3) potential for elevated clogging risk is considered. □ A minimum of 2 inches of freeboard is provided. Freeboard provides room for head over overflow structures and minimizes risk of uncontrolled surface discharge. □ Side slopes are stabilized with vegetation and are ≥ 3H: 1V. Gentler side slopes are safer, less prone to erosion, able to establish vegetation more quickly and easier to maintain. Vegetation □ Plantings are suitable for the climate and expected ponding depth. A plant list to aid in selection can be found in Appendix F. Plants suited to the climate and ponding depth are more likely to survive. □ An irrigation system with a connection to water supply is provided as needed. Seasonal irrigation might be needed to keep plants healthy. Mulch (Mandatory) □ 3 inches of shredded hardwood mulch. Mulch must be non-floating to avoid clogging of overflow structure. Mulch will suppress weeds and maintain moisture for plant growth. X X X X X X INF-2 Bioretention www.sandiegocounty.gov/stormwater E-74 Effective September 15, 2020 Siting and Design Intent/Rationale Media Layer □ Media maintains a minimum filtration rate of 5 in/hr over lifetime of facility. A minimum initial filtration rate of 10 in/hr is recommended. A high filtration rate through the soil mix minimizes clogging potential and allows flows to quickly enter the aggregate storage layer, thereby minimizing bypass. □ Media is a minimum 18 inches deep, meeting either of these two media specifications: Media Specifications listed in Appendix F-3 Biofiltration Soil Media (BSM) or County of San Diego Low Impact Development Handbook: Appendix G - Bioretention Soil Specification (June 2014, unless superseded by more recent edition). A deep media layer provides additional filtration and supports plants with deeper roots. Standard specifications must be followed. □ Alternatively, for proprietary designs and custom media mixes not meeting the media specifications contained in the County LID Handbook, the media meets the pollutant treatment performance criteria in Section F.1.1. For non-standard or proprietary designs, compliance with F.1.1 ensures that adequate treatment performance will be provided. □ Media surface area is 3% of contributing area times adjusted runoff factor or greater. Greater surface area to tributary area ratios decrease loading rates per square foot and therefore increase longevity. Adjusted runoff factor is to account for site design BMPs implemented upstream of the BMP (such as rain barrels, impervious area dispersion, etc.). Refer to Appendix B guidance. If media surface area is under 3% of contributing area, refer to Sediment Loading calculations in Appendix B. Filter Course Layer (Optional) □ A filter course is used to prevent migration of fines through layers of the facility. Filter fabric is not used. Migration of media can cause clogging of the aggregate storage layer void spaces or subgrade. Filter fabric is more likely to clog. X X INF-2 Bioretention www.sandiegocounty.gov/stormwater E-75 Effective September 15, 2020 Siting and Design Intent/Rationale □ Filter course is a minimum of 6 inches thick provided in two separate 3 inch layers. The top layer shall be made of ASTM C33 choker sand and the bottom layer shall be of ASTM No. 8 aggregate. Marker stakes shall be used to ensure uniform lift thickness. To prevent reduction of the available storage volume that would lead to clogging of the underdrain and native soil beneath the BMP. □ Filter course is washed and free of fines. Washing aggregate will help eliminate fines that could clog the facility and impede infiltration. □ Filter course calculations assessing suitability for particle migration prevention have been completed. Gradation relationship between layers can evaluate factors (e.g., bridging, permeability, and uniformity) to determine if particle sizing is appropriate or if an intermediate layer is needed. Aggregate Storage Layer (Optional) □ Class 2 Permeable per Caltrans specification 68-1.025 is recommended for the storage layer. Washed, open-graded crushed rock may be used, however a 4-6 inch washed pea gravel filter course layer at the top of the crushed rock is required. Washing aggregate will help eliminate fines that could clog the aggregate storage layer void spaces or subgrade. □ Maximum aggregate storage layer depth is determined based on the infiltration storage volume that will infiltrate within a 36-hour drawdown time. A maximum drawdown time to facilitate provision of adequate storm water storage for the next storm event. The applicant has an option to use a different drawdown time of up to 120 hours if the volume of the facility is adjusted using the percent capture method in Appendix B.4.1. Inflow and Overflow Structures □ Inflow and overflow structures are accessible for inspection and maintenance. Overflow structures must be connected to downstream storm drain system or appropriate discharge point. Maintenance will prevent clogging and ensure proper operation of the flow control structures. X X X INF-2 Bioretention www.sandiegocounty.gov/stormwater E-76 Effective September 15, 2020 Siting and Design Intent/Rationale □ Inflow velocities are limited to 3 ft/s or less or use energy dissipation methods (e.g., riprap, level spreader) for concentrated inflows. High inflow velocities can cause erosion, scour and/or channeling. □ Curb cut inlets are at least 12 inches wide, have a 4-6 inch reveal (drop) and an apron and energy dissipation as needed. Inlets must not restrict flow and apron prevents blockage from vegetation as it grows in. Energy dissipation prevents erosion. □ Overflow is safely conveyed to a downstream storm drain system or discharge point. Size overflow structure to pass 100- year peak flow for on-line basins and water quality peak flow for off-line basins. Planning for overflow lessens the risk of property damage due to flooding. Conceptual Design and Sizing Approach for Storm Water Pollutant Control Only To design bioretention for storm water pollutant control only (no flow control required), the following steps should be taken: 1. Verify that siting and design criteria have been met, including placement and basin area requirements, maximum side and finish grade slope, and the recommended media surface area tributary ratio. 2. Calculate the DCV per Appendix B based on expected site design runoff for tributary areas. 3. Use the sizing worksheet to determine if full infiltration of the DCV is achievable based on the available infiltration storage volume calculated from the bioretention without underdrain footprint area, effective depths for surface ponding, media and aggregate storage layers, and in-situ soil design infiltration rate for a maximum 36-hour drawdown time for the aggregate storage layer (unless percent capture method is used), with surface ponding no greater than a maximum 24-hour drawdown. The drawdown time can be estimated by dividing the average depth of the basin by the design infiltration rate of the underlying soil. Appendix D provides guidance on evaluating a site’s infiltration rate. A generic sizing worksheet is provided in Appendix B.4. 4. Where the DCV cannot be fully infiltrated based on the site or bioretention constraints, an underdrain can be added to the design (use biofiltration with partial retention factsheet). Conceptual Design and Sizing Approach when Storm Water Flow Control is Applicable Control of flow rates and/or durations will typically require significant surface ponding and/or aggregate storage volumes, and therefore the following steps should be taken prior to determination of storm water pollutant control design. Pre-development and allowable post-project flow rates and durations must be determined as discussed in Chapter 6 of the manual. X X INF-2 Bioretention www.sandiegocounty.gov/stormwater E-77 Effective September 15, 2020 1. Verify that siting and design criteria have been met, including placement requirements, maximum side and finish grade slopes, and the recommended media surface area tributary area ratio. Design for flow control can be achieved using various design configurations. 2. Iteratively determine the facility footprint area, surface ponding and/or aggregate storage layer depth required to provide infiltration storage to reduce flow rates and durations to allowable limits while adhering to the maximum drawdown times for surface ponding and aggregate storage. Flow rates and durations can be controlled using flow splitters that route the appropriate inflow amounts to the bioretention facility and bypass excess flows to the downstream storm drain system or discharge point. 3. If bioretention without underdrain facility cannot fully provide the flow rate and duration control required by the MS4 permit, an upstream or downstream structure with appropriate storage volume such as an underground vault can be used to provide additional control. 4. After bioretention without underdrain BMPs have been designed to meet flow control requirements, calculations must be completed to verify if storm water pollutant control requirements to treat the DCV have been met. Maintenance Overview Normal Expected Maintenance. Bioretention requires routine maintenance to: remove accumulated materials such as sediment, trash or debris; maintain vegetation health; maintain infiltration capacity of the media layer; replenish mulch; and maintain integrity of side slopes, inlets, energy dissipators, and outlets. A summary table of standard inspection and maintenance indicators is provided within this Fact Sheet. Non-Standard Maintenance or BMP Failure. If any of the following scenarios are observed, the BMP is not performing as intended to protect downstream waterways from pollution and/or erosion. Corrective maintenance, increased inspection and maintenance, BMP replacement, or a different BMP type will be required. • The BMP is not drained between storm events. Surface ponding longer than approximately 24 hours following a storm event may be detrimental to vegetation health, and surface ponding longer than approximately 96 hours following a storm event poses a risk of vector (mosquito) breeding. Poor drainage can result from clogging of the media layer, filter course, aggregate storage layer, underlying native soils, or outlet structure. The specific cause of the drainage issue must be determined and corrected. If it is determined that the underlying native soils have been compacted or do not have the infiltration capacity expected, the County reviewer shall be contacted prior to any additional repairs or reconstruction. • Sediment, trash, or debris accumulation greater than 25% of the surface ponding volume within one month. This means the load from the tributary drainage area is too high, reducing BMP function or clogging the BMP. This would require pretreatment measures within the tributary area draining to the BMP to intercept the materials. Pretreatment components, especially for sediment, will extend the life of components that are more expensive to replace INF-2 Bioretention www.sandiegocounty.gov/stormwater E-78 Effective September 15, 2020 such as media, filter course, and aggregate layers. • Erosion due to concentrated storm water runoff flow that is not readily corrected by adding erosion control blankets, adding stone at flow entry points, or minor re-grading to restore proper drainage according to the original plan. If the issue is not corrected by restoring the BMP to the original plan and grade, the County reviewer shall be contacted prior to any additional repairs or reconstruction. Other Special Considerations. Bioretention is a vegetated structural BMP. Vegetated structural BMPs that are constructed in the vicinity of, or connected to, an existing jurisdictional water or wetland could inadvertently result in creation of expanded waters or wetlands. As such, vegetated structural BMPs have the potential to come under the jurisdiction of the United States Army Corps of Engineers, SDRWQCB, California Department of Fish and Wildlife, or the United States Fish and Wildlife Service. This could result in the need for specific resource agency permits and costly mitigation to perform maintenance of the structural BMP. Along with proper placement of a structural BMP, routine maintenance is key to preventing this scenario. INF-2 Bioretention www.sandiegocounty.gov/stormwater E-79 Effective September 15, 2020 Summary of Standard Inspection and Maintenance The property owner is responsible to ensure inspection, operation and maintenance of permanent BMPs on their property unless responsibility has been formally transferred to an agency, community facilities district, homeowners association, property owners association, or other special district. Maintenance frequencies listed in this table are average/typical frequencies. Actual maintenance needs are site-specific, and maintenance may be required more frequently. Maintenance must be performed whenever needed, based on maintenance indicators presented in this table. The BMP owner is responsible for conducting regular inspections to see when maintenance is needed based on the maintenance indicators. During the first year of operation of a structural BMP, inspection is recommended at least once prior to August 31 and then monthly from September through May. Inspection during a storm event is also recommended. After the initial period of frequent inspections, the minimum inspection and maintenance frequency can be determined based on the results of the first year inspections. Threshold/Indicator Maintenance Action Inspection and Maintenance Frequency Accumulation of sediment, litter, or debris Remove and properly dispose of accumulated materials, without damage to the vegetation or compaction of the media layer. • Inspect monthly. If the BMP is 25% full* or more in one month, increase inspection frequency to monthly plus after every 0.1- inch or larger storm event. • Remove any accumulated materials found at each inspection. Obstructed inlet or outlet structure Clear blockage. • Inspect monthly and after every 0.5-inch or larger storm event. • Remove any accumulated materials found at each inspection. Damage to structural components such as weirs, inlet or outlet structures Repair or replace as applicable. • Inspect annually. • Maintain when needed. Poor vegetation establishment Re-seed, re-plant, or re-establish vegetation per original plans. • Inspect monthly. • Maintain when needed. INF-2 Bioretention www.sandiegocounty.gov/stormwater E-80 Effective September 15, 2020 Threshold/Indicator Maintenance Action Inspection and Maintenance Frequency Dead or diseased vegetation Remove dead or diseased vegetation, re-seed, re-plant, or re-establish vegetation per original plans. • Inspect monthly. • Maintain when needed. Overgrown vegetation Mow or trim as appropriate. • Inspect monthly. • Maintain when needed. 2/3 of mulch has decomposed, or mulch has been removed Remove decomposed fraction and top off with fresh mulch to a total depth of 3 inches. • Inspect monthly. • Replenish mulch annually, or more frequently when needed based on inspection. Erosion due to concentrated irrigation flow Repair/re-seed/re-plant eroded areas and adjust the irrigation system. • Inspect monthly. • Maintain when needed. Erosion due to concentrated storm water runoff flow Repair/re-seed/re-plant eroded areas, and make appropriate corrective measures such as adding erosion control blankets, adding stone at flow entry points, or minor re-grading to restore proper drainage according to the original plan. If the issue is not corrected by restoring the BMP to the original plan and grade, the County reviewer shall be contacted prior to any additional repairs or reconstruction. • Inspect after every 0.5-inch or larger storm event. If erosion due to storm water flow has been observed, increase inspection frequency to after every 0.1-inch or larger storm event. • Maintain when needed. If the issue is not corrected by restoring the BMP to the original plan and grade, the County reviewer shall be contacted prior to any additional repairs or reconstruction. Standing water in BMP for longer than 24 hours following a storm event Surface ponding longer than approximately 24 hours following a storm event may be detrimental to vegetation health Make appropriate corrective measures such as adjusting irrigation system, removing obstructions of debris or invasive vegetation, or repairing/replacing clogged or compacted soils. If it is determined that the underlying native soils have been compacted or do not have the infiltration capacity expected, the County reviewer shall be contacted prior to any additional repairs or reconstruction. • Inspect monthly and after every 0.5-inch or larger storm event. If standing water is observed, increase inspection frequency to after every 0.1-inch or larger storm event. • Maintain when needed. INF-2 Bioretention www.sandiegocounty.gov/stormwater E-81 Effective September 15, 2020 Threshold/Indicator Maintenance Action Inspection and Maintenance Frequency Presence of mosquitos/larvae For images of egg rafts, larva, pupa, and adult mosquitos, see http://www.mosquito.org/biology If mosquitos/larvae are observed: first, immediately remove any standing water by dispersing to nearby landscaping; second, make corrective measures as applicable to restore BMP drainage to prevent standing water. If mosquitos persist following corrective measures to remove standing water, or if the BMP design does not meet the 96-hour drawdown criteria because the underlying native soils have been compacted or do not have the infiltration capacity expected, the County reviewer shall be contacted to determine a solution. A different BMP type, or a Vector Management Plan prepared with concurrence from the County of San Diego Department of Environmental Health, may be required. • Inspect monthly and after every 0.5-inch or larger storm event. If mosquitos are observed, increase inspection frequency to after every 0.1-inch or larger storm event. • Maintain when needed. “25% full” is defined as ¼ of the depth from the design bottom elevation to the crest of the outflow structure (e.g., if the height to the outflow opening is 12 inches from the bottom elevation, then the materials must be removed when there is 3 inches of accumulation – this should be marked on the outflow structure). Attachment 1F STRUCTURAL BMP INVENTORY PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 11 Template Date: August 14th, 2022 Preparation Date:________________ Attachment 1f: Structural BMP Inventory Stormwater Structural Pollutant Control & Hydromodification Control BMPs* (List all from WQMP) Description/Type of Structural BMP Plan Sheet # BMP ID# DMA ID No. Revisions Bioretention Basin 1 Basin A DMA A Bioretention Basin 1 Basin B DMA B Attachment 1G STRUCTURAL POLLUTANT CON TROL BMP CHECKLIST 12 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 1g: Structural Pollutant Control BMP Checklist Provide the following items for each Structural BMP selected Refer to Figure 5-2: Stormwater Pollutant Control Structural BMP Selection Flow Chart Not included because the entire project is designed with Self-Mitigating, De-Minimis, or Self- Retaining DMAs. The project is compliant with Pollution Control BMP sizing requirements. DMA ID No. DMA A Structural BMP ID No. Basin A Construction Plan Sheet No. 1 Geotechnical/ Soils Engineering Recommendations: Worksheet C.4-1: Categorization of Infiltration Feasibility Condition Full Infiltration Partial Infiltration No Infiltration Worksheet D.5-1: Factor of Safety and Design Infiltration Rate Design Infiltration rate ____0.04_____ (in/hr) Structural BMP Selection and Design (Chapter 5.5) complete and include the applicable worksheet(s) found in appendix B (color coded Green below) and design criteria checklists from the associated fact sheets found in appendix E (color coded Orange below) for selected Structural BMP(s): Worksheet B.6-1 - Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) Retention by harvest and use (HU-1) Continuous simulation Model Worksheet B.4-1 Infiltration basin (INF-1) Bioretention (INF-2) Permeable pavement (INF-3) Worksheet B.5-1 Biofiltration with partial retention (PR-1) Biofiltration (BF-1) Biofiltration with Nutrient Sensitive Media Design (BF-2) Proprietary Biofiltration (BF-3) Appendix F checklist Worksheet B.5-3 Minimum Footprint Worksheet B.5-4 Biofiltration + Storage Selected BMPs have been designed to address the entire DCV. The DMA is compliant with Pollution Control BMP sizing requirements. STOP * Other (describe in discussion section below) PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 13 Template Date: August 14th, 2022 Preparation Date:________________ Worksheet B.6-1 - Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) Describe in discussion section below why the remaining BMP size could not fit on site. Selection of Flow-Thru Treatment Control BMPs with high or medium effectiveness Vegetated swales (FT-1) Media Filters (FT-2) Sand Filters (FT-3) Dry Extended Detention Basin (FT-4) Proprietary flow-thru treatment control (FT-5) Water Quality Equivalency Worksheets20 Purpose: Pre-treatment/forebay for another structural BMP Pollutant control only Combined pollutant control and hydromodification control (see Attachment 2) Other (describe in discussion section below) Who will certify construction of this BMP? Provide name and contact information for the party responsible to sign BMP verification forms (See Chapter 1.12 of the BMP Design Manual) Who will be the final owner of this BMP? HOA Property Owner City Other (describe) Who will maintain this BMP into perpetuity? HOA Property Owner City Other (describe) Discussion (as needed): * If this box is checked, Worksheet B.6-1 does not need to be filled out. 14 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 1g: Structural Pollutant Control BMP Checklist Provide the following items for each Structural BMP selected Refer to Figure 5-2: Stormwater Pollutant Control Structural BMP Selection Flow Chart Not included because the entire project is designed with Self-Mitigating, De-Minimis, or Self- Retaining DMAs. The project is compliant with Pollution Control BMP sizing requirements. DMA ID No. DMA B Structural BMP ID No. Basin B Construction Plan Sheet No. 1 Geotechnical/ Soils Engineering Recommendations: Worksheet C.4-1: Categorization of Infiltration Feasibility Condition Full Infiltration Partial Infiltration No Infiltration Worksheet D.5-1: Factor of Safety and Design Infiltration Rate Design Infiltration rate ____0.04_____ (in/hr) Structural BMP Selection and Design (Chapter 5.5) complete and include the applicable worksheet(s) found in appendix B (color coded Green below) and design criteria checklists from the associated fact sheets found in appendix E (color coded Orange below) for selected Structural BMP(s): Worksheet B.6-1 - Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) Retention by harvest and use (HU-1) Continuous simulation Model Worksheet B.4-1 Infiltration basin (INF-1) Bioretention (INF-2) Permeable pavement (INF-3) Worksheet B.5-1 Biofiltration with partial retention (PR-1) Biofiltration (BF-1) Biofiltration with Nutrient Sensitive Media Design (BF-2) Proprietary Biofiltration (BF-3) Appendix F checklist Worksheet B.5-3 Minimum Footprint Worksheet B.5-4 Biofiltration + Storage Selected BMPs have been designed to address the entire DCV. The DMA is compliant with Pollution Control BMP sizing requirements. STOP * Other (describe in discussion section below) Worksheet B.6-1 - Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) Describe in discussion section below why the remaining BMP size could not fit on site. Selection of Flow-Thru Treatment Control BMPs with high or medium effectiveness Vegetated swales (FT-1) Media Filters (FT-2) Sand Filters (FT-3) Dry Extended Detention Basin (FT-4) Proprietary flow-thru treatment control (FT-5) Water Quality Equivalency Worksheets20 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 15 Template Date: August 14th, 2022 Preparation Date:________________ Purpose: Pre-treatment/forebay for another structural BMP Pollutant control only Combined pollutant control and hydromodification control (see Attachment 2) Other (describe in discussion section below) Who will certify construction of this BMP? Provide name and contact information for the party responsible to sign BMP verification forms (See Chapter 1.12 of the BMP Design Manual) Who will be the final owner of this BMP? HOA Property Owner City Other (describe) Who will maintain this BMP into perpetuity? HOA Property Owner City Other (describe) Discussion (as needed): * If this box is checked, Worksheet B.6-1 does not need to be filled out. Category # Description i ii iii iv v vi vii viii ix x Units 0 Drainage Basin ID or Name A B - - - - - - - - unitless 1 Design Infiltration Rate Recommended by Geotechnical Engineer 5.000 5.000 - - - - - - - - in/hr 2 Design Capture Volume Tributary to BMP 3,795 2,205 - - - - - - - - cubic-feet 3 Is Retention BMP Vegetated or Non-Vegetated?Vegetated Vegetated unitless 4 Provided Surface Area 2,412 2,094 sq-ft 5 Provided Surface Ponding Depth 6 6 inches 6 Provided Soil Media Thickness 36 18 inches 7 Provided Gravel Storage Thickness 12 12 inches 8 Volume Infiltrated Over 6 Hour Storm 3,795 2,205 0 0 0 0 0 0 0 0 cubic-feet 9 Soil Media Pore Space 0.25 0.25 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 unitless 10 Gravel Pore Space 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 0.40 unitless 11 Effective Depth of Retention Storage 19.8 15.3 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 inches 12 Drawdown Time for Surface Ponding (Post-Storm) 1 1 0 0 0 0 0 0 0 0 hours 13 Drawdown Time for Entire Basin (Including 6 Hour Storm) 10 9 0 0 0 0 0 0 0 0 hours 14 Volume Retained by BMP 7,775 4,875 0 0 0 0 0 0 0 0 cubic-feet 15 Fraction of DCV Retained 2.05 2.21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ratio 16 Percentage of Performance Requirement Satisfied 1.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ratio 17 Fraction of DCV Retained (normalized to 36-hr drawdown) 1.00 1.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ratio 18 This BMP Overflows to the Following Drainage Basin - - - - - - - - - - unitless Result 19 Deficit of Effectively Treated Stormwater 0 0 n/a n/a n/a n/a n/a n/a n/a n/a cubic-feet Worksheet B.4-1 General Notes: False Automated Worksheet B.4-1: Sizing Retention BMPs (V1.3) False False False A. Applicants may use this worksheet to size Infiltration, Bioretention, and/or Permeable Pavement BMPs (INF-1, INF-2, INF-3) for up to 10 basins. User input must be provided for yellow shaded cells, values for blue cells are automatically populated based on user inputs from previous worksheets, values for all other cells will be automatically generated, errors/notifications will be highlighted in red/orange and summarized below. BMPs fully satisfying the pollutant control performance standards will have a deficit treated volume of zero and be highlighted in green. False BMP Inputs Infiltration Calculations False False C-11 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1: Categorization of Infiltration Feasibility Condition Categorization of Infiltration Feasibility Condition Worksheet C.4-1 Part 1 - Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Note that it is not necessary to investigate each and every criterion in the worksheet if infiltration is precluded. Instead a letter of justification from a geotechnical professional familiar with the local conditions substantiating any geotechnical issues will be required. Criteria Screening Question Yes No 1 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr BASIN A C-12 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 2 of 4 Criteria Screening Question Yes No 3 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 1 Result* If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a “full infiltration” design. Proceed to Part 2 *To be completed using gathered site information and best professional ju dgment considering the definition of MEP in the Regional MS4 Permit. Additional testing and/or studies may be required by C ity staff to substantiate findings. X X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr C-13 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 3 of 4 Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria Screening Question Yes No 5 Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. X X Geotechnical evaluation found no geotechnical hazards that would have been due to the implementation of infiltration BMPs. Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr C-14 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 4 of 4 Criteria Screening Question Yes No 7 Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. *To be completed using gathered site information and best professional judgment considering the definition of MEP in the Regional MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. X Geotechnical evaluation found that groundwater depth was significantly deep and that there were no special pollutants. X Downstream water body for site is a pond central to the school. School pond water is provided by pumped reclaimed water if not provided from storm events. Therefor, this wouldn't impact downstream water rights. Appendix D: Approved Infiltration Rate Assessment Methods D-19 July 2018 Worksheet D.5-1: Factor of Safety and Design Infiltration Rate Worksheet Factor of Safety and Design Infiltration Rate Worksheet Worksheet D.5-1 Factor Category Factor Description Assigned Weight (w) Factor Value (v) Product (p) p = w x v A Suitability Assessment Soil assessment methods 0.25 Predominant soil texture 0.25 Site soil variability 0.25 Depth to groundwater / impervious layer 0.25 Suitability Assessment Safety Factor, SA = p B Design Level of pretreatment/ expected sediment loads 0.5 Redundancy/resiliency 0.25 Compaction during construction 0.25 Design Safety Factor, SB = p Combined Safety Factor, Stotal= SA x SB Observed Infiltration Rate, inch/hr, Kobserved (corrected for test-specific bias) Design Infiltration Rate, in/hr, Kdesign = Kobserved / Stotal Supporting Data Briefly describe infiltration test and provide reference to test forms: Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr within Pauba soils which are located in locations of shallow cuts (eg. all basins). Infiltration test was done using double-ring infiltrameter testing. .251 .753 .52 .251 1.53 .52 .253 2.25 1.75 3.94 0.15 0.04 BASIN A C-11 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1: Categorization of Infiltration Feasibility Condition Categorization of Infiltration Feasibility Condition Worksheet C.4-1 Part 1 - Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Note that it is not necessary to investigate each and every criterion in the worksheet if infiltration is precluded. Instead a letter of justification from a geotechnical professional familiar with the local conditions substantiating any geotechnical issues will be required. Criteria Screening Question Yes No 1 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr BASIN B C-12 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 2 of 4 Criteria Screening Question Yes No 3 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 1 Result* If all answers to rows 1 - 4 are “Yes” a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is “No”, infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a “full infiltration” design. Proceed to Part 2 *To be completed using gathered site information and best professional ju dgment considering the definition of MEP in the Regional MS4 Permit. Additional testing and/or studies may be required by C ity staff to substantiate findings. X X Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr C-13 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 3 of 4 Part 2 – Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria Screening Question Yes No 5 Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. X X Geotechnical evaluation found no geotechnical hazards that would have been due to the implementation of infiltration BMPs. Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr. Reliable infiltration rate = 0.15/3.94 = 0.04 inches/hr C-14 July 2018 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-1 Page 4 of 4 Criteria Screening Question Yes No 7 Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. *To be completed using gathered site information and best professional judgment considering the definition of MEP in the Regional MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. X Geotechnical evaluation found that groundwater depth was significantly deep and that there were no special pollutants. X Downstream water body for site is a pond central to the school. School pond water is provided by pumped reclaimed water if not provided from storm events. Therefor, this wouldn't impact downstream water rights. Appendix D: Approved Infiltration Rate Assessment Methods D-19 July 2018 Worksheet D.5-1: Factor of Safety and Design Infiltration Rate Worksheet Factor of Safety and Design Infiltration Rate Worksheet Worksheet D.5-1 Factor Category Factor Description Assigned Weight (w) Factor Value (v) Product (p) p = w x v A Suitability Assessment Soil assessment methods 0.25 Predominant soil texture 0.25 Site soil variability 0.25 Depth to groundwater / impervious layer 0.25 Suitability Assessment Safety Factor, SA = p B Design Level of pretreatment/ expected sediment loads 0.5 Redundancy/resiliency 0.25 Compaction during construction 0.25 Design Safety Factor, SB = p Combined Safety Factor, Stotal= SA x SB Observed Infiltration Rate, inch/hr, Kobserved (corrected for test-specific bias) Design Infiltration Rate, in/hr, Kdesign = Kobserved / Stotal Supporting Data Briefly describe infiltration test and provide reference to test forms: Per geotechnical report dated June 15, 2015 the infiltration rate at the test location is 0.15 inches/hr within Pauba soils which are located in locations of shallow cuts (eg. all basins). Infiltration test was done using double-ring infiltrameter testing. .251 .753 .52 .251 1.53 .52 .253 2.25 1.75 3.94 0.15 0.04 BASIN B Attachment 1I OFFSITE ALTERNATIVE COMPLIANCE PARTICIPATION FORM-POLLUTANT CONTROL 16 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 1i: Offsite Alternative Compliance Participation Form - Pollutant Control Refer to Chapter 1.8 Onsite Project Information Record ID: Assessor's Parcel Number(s) [APN(s)] Quantity of Pollutant Control Debits or Credits (cubic feet) Debits Credits *See Attachment 1 of the PDP WQMP Land Use Designation Agriculture Rural Residential Commercial Single Family Residential Education Transportation Industrial Vacant / Open Space Multi Family Residential Water Orchard Total Offsite Project Information – Projects providing or receiving credits (add rows as needed) Record ID: APN(s) Project Owner/Address Credit/Debit Quantity (cubic feet) 1. Credit Debit 2. Credit Debit 3. Credit Debit Total sum of Credits and Debits (∑Credits -∑Debits) (cubic feet) Additional Information Are offsite project(s) in the same credit trading area as the onsite project? Yes No Will projects providing credits be completed prior to completion of projects receiving credits? Yes No Are all deficits accounted for? If No, onsite and offsite projects must be redesigned to account for all deficits. Yes No Provide Alternative Compliance In-Lieu Fee Agreement and supporting WQE calculations as part of this attachment. PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 17 Template Date: August 14th, 2022 Preparation Date:________________ ATTACHMENT 2 HYDROMODIFICATION CONTROL MEASURES Indicate which Items are Included behind this cover sheet: Attachment Sequence Contents Checklist Attachment 2a Do Hydromodification Management Requirements apply? See Chapter 1.6 and Figure 1-2. ☐ Green Streets Project (Exempt from hydromodification management requirements) STOP * ☐ Exempt from hydromodification management requirements. Include Figure 1-2 and document any “YES” answer STOP * Hydromodification management controls required. Attachment 2b HMP Exhibits (Required) See Checklist on the back of this Attachment cover sheet. see Chapter 6.3.1 ☐ Combined with DMA Exhibit Included Attachment 2c Management of Critical Coarse Sediment Yield Areas See Chapter 6.2 and Appendix H of the BMP Design Manual. Exhibit depicting onsite/ upstream CCSYAs (Figure H.1-1) AND, documentation that project avoids CCSYA per Appendix H.1. OR ☐ Sediment Supply BMPs implemented. Attachment 2d Structural BMP Design Calculations, Drawdown Calculations, & Overflow Design. See Chapter 6 & Appendix G of the BMP Design Manual Included ☐ Project is designed entirely with De-Minimus, Self–Mitigating, and/or qualifying Self-Retaining Areas. STOP * Attachment 2e Geomorphic Assessment of Receiving Channels. See Chapter 6.3.4 of the BMP Design Manual. low flow threshold is 0.1Q2 ☐ low flow threshold is 0.3Q2 ☐ low flow threshold is 0.5Q2 Attachment 2f Vector Control Plan (Required when structural BMPs will not drain in 96 hours) ☐ Included Not required because BMPs will drain in less than 96 hours Attachment 2g Hydromodification Offsite Alternative Compliance form. Refer to Figure 1- 3: Pathways to Participating in Offsite Alternative Compliance Program Full Compliance Onsite Offsite ACP. Document onsite structural BMPs and complete Hydromodification Offsite Alternative Compliance Participation Form, and WQE worksheets * If this box is checked, the remainder of Attachment 2 does not need to be filled out. Attachment 2A APPLICABILITY OF HYDROMODIFICATION MANAGEMENT BMP REQUIREMENTS 18 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 2a: Applicability of Hydromodification Management BMP Requirements NO NO YES 1. Is the project a PDP? YES NO YES 2. Direct discharge to Pacific Ocean? NO YES 3. Direct discharge to enclosed embayment, not within protected area? YES 4. Direct discharge to water storage reservoir or lake, below spillway or normal operating level? 5. Direct discharge to an area identified in WMAA? NO Exempt from hydromodification management requirements Hydromodification management controls required WILDOMAR MURRIETA CANYONLAKE LAKE ELSINORE TEMECULA HEMET MENIFEE D I A M O N D V A L L E YL A K E L A K ES K I N N E R C A N Y O NL A K E L A K EE L S I N O R E LAKESKINNER VAIL LAKE °0 1 2 3 4Miles HCOC Applicability MapHCOC Applicability Map Map Document: (M:\Mdata\10108202\RCFCWCD_Hydromodification_Large_5500.mxd.mxd - IRV) - 1/9/2012 Legend Lakes/Reservoirs Stream Type Not Susceptible Not Susceptible (Over 20,000 cfs) Susceptible Watershed Areas Not Applicable Area Applicable Area Applicable Area Watershed Boundaries Santa Margarita Watershed County Boundary Study Area Hydromodification Susceptibility Documentation Report and MappingRiverside County Flood Control and Water Conservation DistrictSanta Margarita Region - Map 2 Project Site Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas July 2018 H-7 Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas Figure H.2-1: Potential Critical Coarse Sediment Yield Areas and Potential Sediment Source Areas Project Site Attachment 2B DMA EXHIBIT CHECKLIST PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 19 Template Date: August 14th, 2022 Preparation Date:________________ Attachment 2b: DMA Exhibit Checklist Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit: Point(s) of Compliance with name or number Project Site Boundary Project Disturbed Area Footprint Drainage management area (DMA) boundaries, DMA ID numbers, DMA areas (square footage or acreage), and DMA type (i.e., drains to structural BMP, self-retaining, self- mitigating, or de-minimis) Note on exhibit De-minimis areas and reason they could not be included. Include offsite areas receiving treatment to mitigate Onsite Water Quality Equivalency. Potential pollutant source areas and corresponding required source control BMPs (see Chapter 4, Appendix E.1, and Step 3.5) Proposed Site Design BMPs and surface treatments used to minimize imperviousness. Show sections, details, and dimensions of site design BMP’s (tree wells, dispersion areas, rain gardens, permeable pavement, rain barrels, green roofs, etc.) Proposed Harvest and Use BMPs Underlying hydrologic soil group (Web Soil Survey) Existing natural hydrologic features (watercourses, seeps, springs, wetlands, pond, lake) Existing topography and impervious areas Proposed grading and impervious areas. If the project is a subdivision or spans multiple lots show pervious and impervious totals for each lot. Existing and proposed site drainage network and connections to drainage offsite Potable water wells, onsite wastewater treatment systems (septic), underground utilities Structural BMPs (identify location, structural BMP ID No., type of BMP, and size/detail) Approximate depth to groundwater at each structural BMP Approximate infiltration rate and feasibility (full retention, partial retention, biofiltration) at each structural BMP Critical coarse sediment yield areas to be protected and or conveyed through the project site. Temporary Construction BMPs. Include protection of source control, site design and structural BMPs during construction. Onsite and Offsite Critical coarse sediment yield areas to be protected Proposed design features and surface treatments used to minimize imperviousness Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) Attachment 2C MANAGEMENT OF CRITICAL COARSE SEDIMENT YIELD AREAS 20 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Attachment 2c: Management of Critical Coarse Sediment Yield Areas Document the findings of Site-specific Critical Coarse Sediment Analysis below. Include any calculations, and additional documentation completed as part of the analysis. Refer to Chapter 6.2 and Appendix H of the City of Temecula BMP Design Manual for additional guidance. The project effectively manages Critical Coarse Sediment Yield Areas (CCSYAs) using the following methodology: Step A. A Site-Specific Critical Coarse Sediment Yield Analysis was performed: Step A.1. Determine whether the project site is a significant source of critical coarse sediment to the channel receiving runoff (refer to CCSYA mapping in Appendix H): The project site is a significant source of Bed Sediment Supply. All channels on the project site are preserved or bypassed within the site plan. (Complete Step A.2, below) The project site is a source of Bed Sediment Supply. Channels identified as verified critical coarse sediment yield areas are preserved. (Complete Step A.2, below) The Project site is not a significant source of Bed Sediment Supply. (STOP, supporting information provided with this checklist) Impacts to verified CCSYAs cannot be avoided. (Complete Step B, below) Step A.2. Project site design avoids CCSYAs and maintains sediment supply pathways, documentation is provided following this checklist. (STOP, include supporting documentation with this checklist) Step B. Sediment Supply BMPs are implemented onsite to mitigate impacts of development in CCSYAs, documentation is provided following this checklist. (STOP, include supporting documentation with this checklist) PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 21 Template Date: August 14th, 2022 Preparation Date:________________ Hydromodification Offsite Alternative Compliance Participation Form Refer to Chapter 1.8 Onsite Project Information Record ID: Assessor's Parcel Number(s) [APN(s)] Quantity of Hydromodification Debits or Credits (DCIA) Debits Credits *See Attachment 1 of the PDP WQMP Offsite Project Information – Projects providing or receiving credits (add rows as needed) Record ID: APN(s) Project Owner/Address Credit/Debit Quantity (DCIA) 1. Credit Debit 2. Credit Debit 3. Credit Debit 4. Credit Debit 5. Credit Debit 6. Credit Debit Total sum of Credits and Debits (∑Credits -∑Debits) (DCIA) Additional Information Are offsite projects in the same credit trading area as the onsite project? Yes No Do offsite projects discharge directly to the same susceptible stream reach as the onsite project? (required for certain hydromodification scenarios) Yes No Will projects providing credits be completed prior to completion of projects receiving credits? Yes No Are all deficits accounted for? If No, onsite and offsite projects must be redesigned to account for all deficits. Yes No Provide supporting WQE calculations as part of this attachment. 22 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 CHECKLIST 1 Checklist of Items to Include on Plan Sheets Showing Permanent Stormwater BMPs, Source Control, and Site Design Use this checklist to ensure the required information has been included on the plans: The plans must identify: Structural BMP(s) with ID numbers The grading and drainage design shown on the plans must be consistent with the delineation of DMAs shown on the DMA exhibit Improvements within City Public Right-of-Way have been designed in accordance with Appendix K: Guidance on Green Infrastructure. Details and specifications for construction of structural BMP(s). Manufacturer and part number for proprietary parts of structural BMP(s) when applicable. Signage indicating the location and boundary of source control, site design, and structural BMP(s) as required by City staff. How to access the structural BMP(s) to inspect and perform maintenance. Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, benchmarks or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds) Include landscaping plan sheets showing vegetation and amended soil requirements for vegetated structural BMP(s), amended soil areas, dispersion areas, tree-wells, and self- mitigating areas All BMPs must be fully dimensioned on the plans Include all Construction stormwater, source control, and site design measures described in the WQMP. Can be included as separate plan sheets as necessary. When proprietary BMPs are used, site-specific cross section with outflow, inflow, and model number must be provided. Photocopies of general brochures are not acceptable. PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 23 Template Date: August 14th, 2022 Preparation Date:________________ CHECKLIST 2 Checklist for Hydrology/Hydraulic Analysis Use this checklist to ensure the required information has been included on the Hydrology/Hydraulic Analysis : The project is subject to the requirements of City of Temecula Construction, Grading, and Encroachment Ordinance Section 18.06.020 and requires a grading permit and Hydrology Hydraulic Analysis. Prepare Hydrology/Hydraulic Analysis and include all elements of checklist below. The project is exempt from grading permit requirements of City of Temecula Construction, Grading, and Encroachment Ordinance per Section 18.06.060. Document the project exempt category and justification and STOP. Grading Exemption Category (A-O):_____ Discussion/Justification of Exemption: Hydrology/Hydraulic Analysis. The engineer of record shall prepare and submit studies and data regarding hydrology/hydraulic analysis and calculations for ten (10) and one hundred (100) year storm events per Riverside County Flood Control & Water Conservation District Hydrology Manual. Drainage area maps shall also be submitted to determine the quantity of runoff generated by or tributary to the site, and its effects on the site or upon upstream or downstream properties. the study shall include the following but not limited to: In the narrative of the report please provide a summary table of pre- and post- development C, Tc, I, A, V100, Q100 without mitigation and Q100 with mitigation for each area (or point) where drainage discharges from the project. Peak runoff rates (cfs), velocities (fps) and identification of all erosive velocities (at all points of discharge) calculations for pre- development and post-development. The comparisons should be made about the same discharge points for each drainage basin affecting the site and adjacent properties. Summary/Conclusion: Please discuss whether the proposed project would substantially alter the existing drainage pattern of the site or area, including through the alteration of the course of a stream or river, in a manner which would result in substantial erosion or siltation on- or off-site? Provide reasons and mitigations proposed. Provide existing and proposed Hydrology Maps for each phase. The maps shall show existing and proposed culverts, discharge point with A & Q, flow path direction for each drainage basin. Show existing FEMA floodplain/floodway which flow through the property. A minimum map size is 11"x17". Provide Hydrologic Soil Group Map. Provide Rainfall Isopluvials for 100 Year Rainfall Event - 6 Hours and 24 Hours Maps. The report should have numbered pages and a corresponding Table of Contents. Improvements within City Public Right-of-Way have been designed in accordance with Appendix K: Guidance on Green Infrastructure. BMP’s have been designed to safely convey the 100-year flood Limits of Inundation. Said limits on the property, during specified storm frequencies, shall be delineated on the plans; supporting calculations shall also be required. 24 PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS Preparation Date:________________ Template Date: August 14th, 2022 Flood Protection. The engineer of record responsible for plan preparation shall ensure: a. That the building pads to be created through any proposed grading are free from inundation from runoff from specified storms; and b. That floodplain/floodway elevations and widths, sheet flow depths and any other data required by the City Engineer (or by any applicable County, State or Federal flood protection insurance program/requirements) are delineated on the plans. PRIORITY DEVELOPMENT PROJECT (PDP) REQUIREMENTS 25 Template Date: August 14th, 2022 Preparation Date:________________ CHECKLIST 3 Checklist for Geotechnical and Groundwater Investigation Report The report must address the following key elements, and where appropriate, mitigation recommendations must be provided. Identify areas of the project site where infiltration is likely to be feasible and provide justifications for selection of those areas based on soil types, slopes, proximity to existing features, etc. Include completed and signed Worksheet C.4-1. Investigate, evaluate and estimate the vertical infiltration rates and capacities in accordance with the guidance provided in Appendix D which describes infiltration testing and appropriate factor of safety to be applied for infiltration testing results. The site may be broken into sub-basins, each of which has different infiltration rates or capacities. Describe the infiltration/ percolation test results and correlation with published infiltration/ percolation rates based on soil parameters or classification. Recommend providing design infiltration/percolation rate(s) at the sub-basins. Include completed and signed Worksheet D.5-1. Investigate the subsurface geological conditions and geotechnical conditions that would affect infiltration or migration of water toward structures, slopes, utilities, or other features. Describe the anticipated flow path of infiltrated water. Indicate if the water will flow into pavement sections, utility trench bedding, wall drains, foundation drains, or other permeable improvements. Investigate depth to groundwater and the nature of the groundwater. Include an estimate of the high seasonal groundwater elevations. Evaluate proposed use of the site (industrial use, residential use, etc.), soil and groundwater data and provide a concluding opinion whether proposed storm water infiltration could cause adverse impacts to groundwater quality and if it does cause impacts whether the impacts could be reasonably mitigated or not. Estimate the maximum allowable infiltration rates and volumes that could occur at the site that would avoid damage to existing and proposed structures, utilities, slopes, or other features. In addition the report must indicate if the recommended infiltration rate is appropriate based on the conditions exposed during construction. Provide a concluding opinion regarding whether or not the proposed onsite storm water infiltration/percolation BMP will result in soil piping, daylight water seepage, slope instability, or ground settlement. Recommend measures to substantially mitigate or avoid any potentially detrimental effects of the storm water infiltration BMPs or associated soil response on existing or proposed improvements or structures, utilities, slopes or other features within and adjacent to the site. For example, minimize soil compaction. Provide guidance for the selection and location of infiltration BMPs, including the minimum separations between such infiltration BMPs and structures, streets, utilities, manufactured and existing slopes, engineered fills, utilities or other features. Include guidance for measures that could be used to reduce the minimum separations or to mitigate the potential impacts of infiltration BMPs. Attachment 3 SOILS INFORMATION United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for Western Riverside Area, CaliforniaNatural Resources Conservation Service September 15, 2023 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 Western Riverside Area, California.................................................................13 AtD2—Arlington and Greenfield fine sandy loams, 8 to 15 percent slopes, eroded......................................................................................13 RnE3—Ramona and Buren loams, 5 to 25 percent slopes, severely eroded...................................................................................................15 References............................................................................................................17 4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 9 Custom Soil Resource Report Soil Map 37 0 7 0 3 0 37 0 7 0 7 0 37 0 7 1 1 0 37 0 7 1 5 0 37 0 7 1 9 0 37 0 7 2 3 0 37 0 7 2 7 0 37 0 7 3 1 0 37 0 7 0 3 0 37 0 7 0 7 0 37 0 7 1 1 0 37 0 7 1 5 0 37 0 7 1 9 0 37 0 7 2 3 0 37 0 7 2 7 0 37 0 7 3 1 0 489660 489700 489740 489780 489820 489860 489900 489940 489980 490020 490060 489660 489700 489740 489780 489820 489860 489900 489940 489980 490020 490060 33° 30' 19'' N 11 7 ° 6 ' 4 1 ' ' W 33° 30' 19'' N 11 7 ° 6 ' 2 4 ' ' W 33° 30' 9'' N 11 7 ° 6 ' 4 1 ' ' W 33° 30' 9'' N 11 7 ° 6 ' 2 4 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 11N WGS84 0 50 100 200 300 Feet 0 25 50 100 150 Meters Map Scale: 1:2,010 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 Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features 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 1:15,800. 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: Western Riverside Area, California Survey Area Data: Version 15, Sep 6, 2022 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Mar 14, 2022—Mar 17, 2022 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. Custom Soil Resource Report 10 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AtD2 Arlington and Greenfield fine sandy loams, 8 to 15 percent slopes, eroded 13.9 74.6% RnE3 Ramona and Buren loams, 5 to 25 percent slopes, severely eroded 4.7 25.4% Totals for Area of Interest 18.6 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The Custom Soil Resource Report 11 delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Western Riverside Area, California AtD2—Arlington and Greenfield fine sandy loams, 8 to 15 percent slopes, eroded Map Unit Setting National map unit symbol: hcr6 Elevation: 100 to 3,500 feet Mean annual precipitation: 9 to 20 inches Mean annual air temperature: 63 degrees F Frost-free period: 200 to 320 days Farmland classification: Not prime farmland Map Unit Composition Arlington and similar soils:40 percent Greenfield and similar soils:30 percent Minor components:30 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Arlington Setting Landform:Alluvial fans Landform position (three-dimensional):Tread Down-slope shape:Concave Across-slope shape:Convex Parent material:Alluvium derived from granite Typical profile H1 - 0 to 11 inches: fine sandy loam H2 - 11 to 24 inches: sandy loam H3 - 24 to 36 inches: cemented H4 - 36 to 47 inches: coarse sandy loam Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:24 to 40 inches to duripan Drainage class:Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Moderately low to moderately high (0.06 to 0.20 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:5 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 3.2 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: C Ecological site: R019XD029CA - LOAMY Hydric soil rating: No Custom Soil Resource Report 13 Description of Greenfield Setting Landform:Alluvial fans Landform position (three-dimensional):Tread Down-slope shape:Concave Across-slope shape:Convex Parent material:Alluvium derived from granite Typical profile H1 - 0 to 26 inches: fine sandy loam H2 - 26 to 43 inches: fine sandy loam H3 - 43 to 60 inches: loam H4 - 60 to 70 inches: stratified loamy sand to sandy loam Properties and qualities Slope:8 to 15 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat):Moderately high to high (0.57 to 1.98 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:5 percent Maximum salinity:Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water supply, 0 to 60 inches: Moderate (about 8.3 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 4e Hydrologic Soil Group: A Ecological site: R019XD029CA - LOAMY Hydric soil rating: No Minor Components Unnamed, severely eroded Percent of map unit:20 percent Hydric soil rating: No Greenfield Percent of map unit:10 percent Hydric soil rating: No Custom Soil Resource Report 14 RnE3—Ramona and Buren loams, 5 to 25 percent slopes, severely eroded Map Unit Setting National map unit symbol: hcyl Elevation: 250 to 3,500 feet Mean annual precipitation: 10 to 20 inches Mean annual air temperature: 63 degrees F Frost-free period: 230 to 320 days Farmland classification: Not prime farmland Map Unit Composition Ramona and similar soils:55 percent Buren and similar soils:35 percent Minor components:10 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Ramona Setting Landform:Terraces, alluvial fans Landform position (three-dimensional):Tread Down-slope shape:Linear, concave Across-slope shape:Linear, convex Parent material:Alluvium derived from granite Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 17 inches: fine sandy loam H3 - 17 to 68 inches: sandy clay loam H4 - 68 to 74 inches: gravelly sandy loam Properties and qualities Slope:5 to 25 percent Depth to restrictive feature:More than 80 inches Drainage class:Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Moderately high (0.20 to 0.57 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Calcium carbonate, maximum content:1 percent Available water supply, 0 to 60 inches: Moderate (about 8.6 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6e Custom Soil Resource Report 15 Hydrologic Soil Group: C Ecological site: R019XD029CA - LOAMY Hydric soil rating: No Description of Buren Setting Landform:Terraces, alluvial fans Landform position (three-dimensional):Tread Down-slope shape:Linear Across-slope shape:Linear, convex Parent material:Alluvium Typical profile H1 - 0 to 8 inches: loam H2 - 8 to 28 inches: loam H3 - 28 to 37 inches: loam H4 - 37 to 52 inches: cemented Properties and qualities Slope:5 to 25 percent Depth to restrictive feature:37 to 40 inches to duripan Drainage class:Well drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat):Very low to moderately low (0.00 to 0.06 in/hr) Depth to water table:More than 80 inches Frequency of flooding:None Frequency of ponding:None Maximum salinity:Nonsaline to slightly saline (0.0 to 4.0 mmhos/cm) Available water supply, 0 to 60 inches: Low (about 5.8 inches) Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 6e Hydrologic Soil Group: C Ecological site: R019XD060CA - SHALLOW LOAMY Hydric soil rating: No Minor Components Ramona Percent of map unit:4 percent Hydric soil rating: No Buren Percent of map unit:4 percent Hydric soil rating: No Hanford Percent of map unit:2 percent Hydric soil rating: No Custom Soil Resource Report 16 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 17 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 18 170 N. MAPLE STREET, STE 108, CORONA, CA 92880 TELEPHONE: (951) 509-7090 ALTA CALIFORNIA GEOTECHNICAL, INC . B B' Qp Qp Qp Qp Qp Qp Qal af Qal af af af af af af Qal af Qp af af Qp Qal Qal Qp af Qal Qal Qp (Qal) (Qp) af af (Qal) (Qp) (Qp) af Qp af Qal B'B Qal Qp Qp A A' af (Qal) af 170 N. MAPLE STREET, STE 108, CORONA, CA 92880 TELEPHONE: (951) 509-7090 ALTA CALIFORNIA GEOTECHNICAL, INC . ALTA CALIFORNIA GEOTECHNICAL, INC. LINFIELD CHRISTIAN SCHOOL November 15, 2023 31950 Pauba Road Project No. 1‐0502 Temecula CA, 92592 Attention: Mr. Marc Horton Subject: GEOTECHNICAL INVESTIGATION REPORT 31950 Pauba Road, City of Temecula, County of Riverside, California References: Alta California Geotechnical, Inc., 2016, Geotechnical Update Report and Review of Conceptual Grading Plans Linfield Village, APN 955‐020‐006 City of Temecula, California, dated August 31, 2016 by Alta California Geotechnical, Inc. (Project Number 1‐0155A). Alta California Geotechnical, Inc., 2015, Geotechnical Investigation, Linfield Property, Tract 36098‐1, Parcels 1 through 3, and Tract 3698‐2, Parcel 1, City of Temecula, California, dated June 15, 2015 by Alta California Geotechnical, Inc. (Project Number 1‐0155A). Dear Mr. Horton: Presented herein is Alta California Geotechnical, Inc.’s (Alta) geotechnical report for the improvements to be constructed at the Linfield Christian School, located at 31950 Pauba Road, west of the City of Temecula, Riverside County, California. This report is based on Alta’s recent subsurface investigation, laboratory testing, a review of the 1‐inch equals 40 feet scale Preliminary Conceptual Grading Plan, prepared by KWC Engineers, Alta’s previous site investigations, published geologic maps, and Alta’s staff’s experience with similar projects in this vicinity. Alta’s review of the geotechnical data and the conceptual grading plan indicates that the proposed development is feasible, from a geotechnical perspective, provided that the recommendations presented in this report are incorporated into the grading and improvement plans and implemented during site development. Project Number 1‐0502 Page ii November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. Included in this report are:  Discussion of the site geotechnical conditions.  Recommendations for remedial and site grading, including unsuitable soil removals.  Geotechnical site construction recommendations.  Preliminary foundation design parameters. If you have any questions or should you require any additional information, please contact the undersigned at (951) 509‐7090. Alta appreciates the opportunity to provide geotechnical consulting services for your project. Sincerely, Alta California Geotechnical, Inc. ________________________________ YOUSSEF F. HIJAZI Engineering Geology Associate ___________________________________ SCOTT A. GRAY/RGE 2857 Reg. Exp.: 12‐31‐24 Registered Geotechnical Engineer President ___________________________________ THOMAS J. MCCARTHY/CEG 2080 Reg. Exp.: 9‐30‐24 Certified Engineering Geologist Vice President Distribution: (1) Addressee YFH:SAG:TJM 1‐0502 November 15 2023 (Linfield Christian School (Geotechnical Investigation Report Linfield, Temecula CA) Project Number 1‐0502 Page iii November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 1.0 INTRODUCTION ...............................................................................................................1 1.1 Purpose .....................................................................................................................1 1.2 Scope of Work .........................................................................................................1 1.3 Report Limitations ...................................................................................................2 2.0 PROJECT DESCRIPTION ..................................................................................................2 2.1 Site Location and Existing Conditions ....................................................................2 2.2 Proposed Development ............................................................................................2 3.0 SITE INVESTIGATION .....................................................................................................3 3.1 Current Subsurface Investigation .............................................................................3 3.2 Previous Subsurface Investigation ...........................................................................3 4.0 GEOLOGIC CONDITIONS ................................................................................................3 4.1 Geologic and Geomorphic Setting ...........................................................................3 4.2 Stratigraphy ..............................................................................................................4 4.2.1 Topsoil (no map symbol) .............................................................................4 4.2.2 Alluvium (Map symbol Qal) ........................................................................4 4.2.3 Pauba Formation (Map symbol Qp) ............................................................4 4.3 Geologic Structure ...................................................................................................5 4.3.1 Tectonic Framework ....................................................................................5 4.3.2 Regionally Mapped Active Faults ...............................................................5 4.3.3 Geologic Structure .......................................................................................5 4.4 Groundwater ............................................................................................................6 4.5 Earthquake Hazards .................................................................................................6 4.5.1 Local and Regional Faulting ........................................................................6 4.5.2 Seismicity .....................................................................................................6 4.5.3 Surface Rupture ...........................................................................................7 4.5.4 Liquefaction .................................................................................................7 4.5.5 Dry Sand Settlement ....................................................................................7 4.6 Regional Subsidence ................................................................................................8 5.0 ENGINEERING PROPERTIES AND ANALYSIS ...........................................................8 5.1 Materials Properties .................................................................................................8 5.1.1 Excavation Characteristics ...........................................................................8 5.1.2 Compressibility ............................................................................................8 5.1.3 Hydro-Consolidation....................................................................................8 5.1.4 Expansion Potential .....................................................................................9 5.1.5 Earthwork Adjustments ...............................................................................9 5.1.6 Chemical Analyses.....................................................................................10 5.2 Engineering Analysis .............................................................................................10 5.2.1 Bearing Capacity and Lateral Earth Pressures ...........................................10 Project Number 1‐0502 Page iv November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.0 CONCLUSIONS AND RECOMMENDATIONS ............................................................11 6.1 Remedial Grading Recommendations ...................................................................11 6.1.1 Site Preparation ..........................................................................................11 6.1.2 Unsuitable Soil Removals ..........................................................................11 6.1.2.1 Future Maintenance Building .............................................................................. 12 6.1.2.2 Parking Lot .......................................................................................................... 12 6.1.3 Over-Excavation of Building Pads ............................................................13 6.1.3.1 Cut/Fill Transition Pads ...................................................................................... 13 6.1.3.2 Cut Pads............................................................................................................... 13 6.2 General Earthwork Recommendations ..................................................................14 6.2.1 Compaction Standards ...............................................................................14 6.2.2 Groundwater/Seepage ................................................................................14 6.2.3 Documentation of Removals ......................................................................14 6.2.4 Treatment of Removal Bottoms .................................................................15 6.2.5 Fill Placement ............................................................................................15 6.2.6 Moisture Content .......................................................................................15 6.2.7 Mixing ........................................................................................................15 6.2.8 Import Soils ................................................................................................15 6.2.9 Utility Trenches .........................................................................................16 6.2.9.1 Excavation ........................................................................................................... 16 6.2.9.2 Backfill ................................................................................................................ 16 6.2.10 Fill Slope Construction ..............................................................................17 6.2.11 Backcut Stability ........................................................................................18 7.0 DESIGN CONSIDERATIONS .........................................................................................18 7.1 Structural Design ...................................................................................................18 7.2 Moisture Barrier .....................................................................................................19 7.3 Seismic Design.......................................................................................................20 7.4 Block Walls ............................................................................................................21 7.5 Footing Excavations ...............................................................................................21 7.6 Exterior Slabs and Walkways ................................................................................21 7.6.1 Subgrade Compaction ................................................................................21 7.6.2 Subgrade Moisture .....................................................................................21 7.6.3 Concrete Slab Thickness ............................................................................21 7.6.4 Concrete Slab Reinforcement ....................................................................22 7.6.5 Control Joints .............................................................................................22 7.7 Concrete Design .....................................................................................................22 7.8 Corrosion................................................................................................................22 7.9 Pavement Design ...................................................................................................23 7.10 Site Drainage ..........................................................................................................24 Project Number 1‐0502 Page v November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 7.11 Deepened Footings and Setbacks...........................................................................24 8.0 LOT MAINTENANCE .....................................................................................................25 8.1 Lot Drainage ..........................................................................................................25 8.2 Burrowing Animals ................................................................................................26 9.0 FUTURE PLAN REVIEWS ..............................................................................................26 10.0 CLOSURE .........................................................................................................................26 10.1 Geotechnical Review .............................................................................................26 10.2 Limitations .............................................................................................................27 APPENDIX A: REFERENCES APPENDIX B: SUBSURFACE INVESTIGATION APPENDIX B‐1: PREVIOUS SUBSURFACE INVESTIGATION APPENDIX C: LABORATORY TESTING APPENDIX D: EARTHWORK SPECIFICATIONS APPENDIX E: GRADING DETAILS Project Number 1‐0502 Page 1 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 1.0 INTRODUCTION The following report presents Alta’s findings, conclusions, and geotechnical recommendations for the proposed development of Linfield Christian School, located at 31950 Pauba Road, west of the City of Temecula, in Riverside County, California. 1.1 Purpose The purpose of this report is to examine the existing onsite geotechnical conditions and assess the impacts that the geotechnical conditions may have on the proposed development as depicted on the accompanying conceptual grading plan. This report is suitable for submittal to the governing agencies and engineer’s cost estimates. 1.2 Scope of Work Alta’s Scope of Work for this geotechnical investigation included the following:  Review of the referenced literature, maps, reports and aerial photos (Appendix A).  Site geologic mapping.  Excavating, logging, and sampling five (5) hollow‐stem auger borings to a maximum depth of 26.0 feet below existing grade (Appendix B).  Compiling previous subsurface and laboratory data from the referenced reports (Appendix B‐1).  Conducting laboratory testing on samples obtained during our investigation (Appendix C).  Evaluating engineering geologic and geotechnical engineering data, including laboratory data, to develop recommendations for site remedial grading, import soil, foundations and utilities.  Preparing this report and accompanying exhibits. Project Number 1‐0502 Page 2 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 1.3 Report Limitations The conclusions and recommendations presented in this report are based on the field and laboratory information generated during previous investigations and our current investigation, and a review of the referenced reports. The information contained in this report is intended to be used for submittal to appropriate governing agencies and engineers cost estimates. 2.0 PROJECT DESCRIPTION 2.1 Site Location and Existing Conditions The irregular‐shaped, approximately 3.4‐acre site is bounded to the north by Rancho Vista Road, to the south by Linfield Way, and to the east and west by private properties. The site is currently being used as a parking lot for Linfield Christian School. Elevations range from approximately 1230 feet above sea level (ASL) near the northeast corner of the site to approximately 1210 feet (ASL) in the southwest corner of the site providing 20 feet of relief. Review of vintage air photos (Historic Aerials, 2023) indicates that the site was vacant until 1978 when Linfield Christian School and the development near the northeast corner had been constructed. By 2005, Linfield Way had been developed. By 2020, the most recent vintage air photo, the development in the northeast corner still remained, but during Alta’s subsurface investigation it was found the development has since been removed. 2.2 Proposed Development It is our understanding that the site will be developed to support an additional parking lot and the expansion of the existing maintenance yard. Alta anticipates the conventional cut‐and fill‐grading techniques will be used to develop the site. Project Number 1‐0502 Page 3 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 3.0 SITE INVESTIGATION 3.1 Current Subsurface Investigation Alta conducted subsurface investigation on October 19th of 2023 consisting of the excavating, logging, and sampling of five (5) hollow stem auger borings to a maximum depth of 26.0 feet below existing grade. The locations of the exploratory excavations are shown on Plate 1 and the boring logs are presented in Appendix B. Laboratory testing was performed on bulk and ring samples obtained during the field investigation. A brief description of the laboratory test procedures and the test results are presented in Appendix C. 3.2 Previous Subsurface Investigation Alta conducted a subsurface investigation for the overall Linfield site in May of 2015, which consisted of excavating, logging, and sampling of four (4) bucket auger borings (B‐1 through B‐4) and eleven (11) backhoe test pits (T‐10 through T‐17, T‐19, T‐25, and T‐26). The locations of the excavations that are within the limits of this report are shown on Plate 1 and the logs are shown in Appendix B‐ 1. Alta also conducted two (2) preliminary infiltration tests, one within the limits of this report as shown in Plate 1, in geologic units considered representative of the Linfield Property. 4.0 GEOLOGIC CONDITIONS 4.1 Geologic and Geomorphic Setting Regionally, the subject site is located in the Peninsular Ranges geomorphic province, which characterizes the southwest portion of southern California where major right‐lateral active fault zones predominately trend northwest‐ southeast. The Peninsular Ranges province is composed of plutonic and Project Number 1‐0502 Page 4 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. metamorphic rock, with lesser amounts of Tertiary volcanic and sedimentary rock, Quaternary drainage in‐fills and sedimentary veneers. 4.2 Stratigraphy Based on Alta’s review of the geologic literature, and our subsurface investigation, the project site is underlain by the Pauba formation. The Pauba formation consists of Pleistocene‐age older alluvium. This geologic unit is briefly described below. 4.2.1 Topsoil (no map symbol) Relatively thin topsoil covers portions of the site. It consists predominantly of brown silty sand. The topsoil is dry to slightly moist, and medium dense. The average thickness of the topsoil is approximately one (1) foot. 4.2.2 Alluvium (Map symbol Qal) Holocene‐aged alluvium was encountered in limited areas throughout the site, usually within and adjacent to drainages. The alluvium within the site is estimated to be about two and a half (2.5) feet deep. The alluvium overlies the Pauba Formation. The alluvium generally consists of brown, medium grained silty sand, dry, and loose condition. 4.2.3 Pauba Formation (Map symbol Qp) The late‐to‐middle Pleistocene‐age Pauba Formation consists of reddish brown, brown, greenish brown, tan and gray sandy clay, clayey sand, clay, clayey silt, silty clay, silty sand, and sand. The materials encountered were dry to moist, and in a firm/medium dense to very dense condition. Project Number 1‐0502 Page 5 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 4.3 Geologic Structure 4.3.1 Tectonic Framework Jennings (1985) defined eight structural provinces within California that have been classified by predominant regional fault trends and similar fold structure. These provinces are in turn divided into blocks and sub‐blocks that are defined by “major Quaternary faults.” These blocks and sub‐ blocks exhibit similar structural features. Within this framework the site is located within Structural Province I, which is controlled by the dominant northwest trend of the San Andreas Fault and is divided into two blocks, the Coast Range Block and the Peninsular Range Block. The Peninsular Range Block, on which the site is located, is characterized by a series of parallel, northwest trending faults that exhibit right lateral dip‐ slip movement. These faults are terminated by the Transverse Range block to the north and extend southward to the Baja Peninsula. These northwest trending faults divide the Peninsular Range block into eight sub‐blocks. The site is located on the Riverside sub‐block, which is bound on the west by the Elsinore‐Whittier fault zone and on the east by San Jacinto fault zone. 4.3.2 Regionally Mapped Active Faults Several large, active fault systems, including the Elsinore‐Whittier, the San Jacinto, and the San Andreas, occur in the region surrounding the site. These fault systems have been studied extensively and in a large part control the geologic structure of southern California. 4.3.3 Geologic Structure Based upon our site investigation and literature review, the Pauba Formation is neither folded, nor faulted. Project Number 1‐0502 Page 6 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 4.4 Groundwater Groundwater was not encountered on site during our subsurface investigation. Groundwater elevation data from the nearest active groundwater monitoring site, Site ID: 334996N1171201W001 located approximately 0.7 miles southwest of the site, indicates groundwater levels have ranged between 296.2‐ft and 337.0‐ft below the ground surface from 2011 to 2023. 4.5 Earthquake Hazards The subject site is located in southern California, which is a tectonically active area. The type and magnitude of seismic hazards affecting a site are dependent on the distance to the causative fault and the intensity and magnitude of the seismic event. The seismic hazard may be primary, such as surface rupture and/or ground shaking, or secondary, such as liquefaction and/or ground lurching. 4.5.1 Local and Regional Faulting The site is located on the eastern portion of the Riverside sub‐block, where the Elsinore, San Jacinto, Newport‐Inglewood, Rose Canyon, San Joaquin Hills, Chino, and San Andreas faults surround the site at approximately 1.7, 19.5, 29.6, 32.0, 33.3, 34.4, and 35.4 miles away, respectively (USGS, 2008). 4.5.2 Seismicity Ground shaking hazards caused by earthquakes along other active regional faults do exist. The 2022 California Building Code requires use‐ modified spectral accelerations and velocities for most structural designs. Seismic design parameters using soil profile types identified in the 2022 California Building Code are presented in Section 7.3. Project Number 1‐0502 Page 7 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 4.5.3 Surface Rupture Active faults are not known to exist within the project and a review of Special Publication 42 indicates the site is not within a California State designated Earthquake Fault Zone (CGS, 2018). Accordingly, the potential for fault surface rupture on the subject site is nil. 4.5.4 Liquefaction Seismic agitation of relatively loose saturated sands, silty sands, and some silts can result in a buildup of pore pressure. If the pore pressure exceeds the overburden stresses, a temporary quick condition known as liquefaction can occur. Liquefaction effects can manifest in several ways including: 1) loss of bearing; 2) lateral spread; 3) dynamic settlement; and 4) flow failure. Lateral spreading has typically been the most damaging mode of failure. In general, the more recent that a sediment has been deposited, the more likely it will be susceptible to liquefaction. Other factors that must be considered are: groundwater, confining stresses, relative density, and the intensity and duration of seismically‐induced ground shaking. Based on the density of the underlying Pauba Formation, the potential for liquefaction is considered nil. 4.5.5 Dry Sand Settlement Dry sand settlement is the process of settlement of the ground surface during a seismic event in sand layers. Based on our subsurface investigation and our removal/recompaction recommendations, the potential for onsite dry sand settlement is anticipated to be negligible. Project Number 1‐0502 Page 8 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 4.6 Regional Subsidence The site is located in an area designated as susceptible to subsidence by the County of Riverside (RCIT, 2023). Upon implementation of the remedial grading recommendations presented herein, the effects of subsidence on the development are considered to be negligible. 5.0 ENGINEERING PROPERTIES AND ANALYSIS 5.1 Materials Properties Presented herein is a general discussion of the engineering properties of the onsite materials that will be encountered during construction of the proposed development. Descriptions of the soil (Unified Soil Classification System) and in‐ place moisture/density results are presented on the boring logs in Appendix B. 5.1.1 Excavation Characteristics Based on the data provided from the subsurface investigation, it is our opinion that the onsite material possess favorable excavation characteristics such that conventional earth moving equipment can be utilized. 5.1.2 Compressibility Any undocumented artificial fill, alluvium and the upper portions of the Pauba Formation are considered compressible and unsuitable to support the proposed improvements. Recommended removal depths are presented in Section 6.1.2. 5.1.3 Hydro‐Consolidation Hydro‐consolidation is the effect of introducing water into soil that is prone to collapse. Upon loading and initial wetting, the soil structure and apparent strength are altered resulting in almost immediate settlement. That settlement can have adverse impacts on engineered structures, particularly in areas where it is manifested differentially. Differential Project Number 1‐0502 Page 9 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. settlements are typically associated with differential wetting, irregularities in the subsurface soil conditions, and/or irregular loading patterns. Based on laboratory testing (Appendix C), the potential for hydro‐ collapse onsite is minimal and should be within foundation tolerances upon the completion of the recommended unsuitable soil removals. 5.1.4 Expansion Potential Expansion index testing was performed on samples taken during the previous subsurface investigation (Appendix C‐1). Based on the results from the previous investigation, it is anticipated that the majority of materials onsite vary from “very low” to “medium” in expansion potential (0≤EI≤90, Appendix C) when tested per ASTM D: 4829. 5.1.5 Earthwork Adjustments The values presented in Table 5‐1 are deemed appropriate for estimating purposes and may be used in an effort to balance earthwork quantities. As is the case with every project, contingencies should be made to adjust the earthwork balance when grading is in‐progress and actual conditions are better defined. TABLE 5‐2 Earthwork Adjustment Factors Geologic Unit Adjustment Factor Range Average Artificial fill / alluvium / topsoil Shrink 12 to 17% 14% Pauba Formation Shrink 2 to 4% 3% Project Number 1‐0502 Page 10 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 5.1.6 Chemical Analyses Chemical testing was performed on a sample of material underlying the site during the previous investigation. Soluble sulfate test results indicate that the soluble sulfate concentrations of the soils tested are classified as negligible to moderate (Class S0 to S1) per ACI 318‐14. Negligible chloride levels were detected in the onsite soils. Based on laboratory results of soluble sulfate, chloride, and pH testing as presented in Appendix C, the onsite soils are classified as “non‐corrosive” to buried metals and concrete (Caltrans, 2022). Additional discussions on corrosion are presented in Section 7.9. Corrosion tests results are presented in Appendix C. 5.2 Engineering Analysis Presented below is a general discussion of the engineering analysis methods that were utilized to develop the conclusions and recommendations presented in this report. 5.2.1 Bearing Capacity and Lateral Earth Pressures Ultimate bearing capacity values were obtained using the graphs and formula presented in NAVFAC DM‐7.1. Allowable bearing was determined by applying a factor of safety of at least 3 to the ultimate bearing capacity. Static lateral earth pressures were calculated using Rankine methods for active and passive cases. If it is desired to use Coulomb forces, a separate analysis specific to the application can be conducted. Project Number 1‐0502 Page 11 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.0 CONCLUSIONS AND RECOMMENDATIONS Based on Alta’s findings during our subsurface investigation, the laboratory test results, and our staff’s previous experience in the area, it is Alta’s opinion that the development of the site is feasible from a geotechnical perspective. Presented below are recommendations that should be incorporated into site development and construction plans. 6.1 Remedial Grading Recommendations All grading shall be accomplished under the observation and testing of the project geotechnical consultant in accordance with the recommendations contained herein and the County of Riverside criteria. 6.1.1 Site Preparation Vegetation, construction debris, and other deleterious materials are unsuitable as structural fill material and should be disposed of offsite prior to commencing grading/construction. Any septic tanks, seepage pits or wells should be abandoned as per the County of Riverside Department of Health Services. 6.1.2 Unsuitable Soil Removals Presented below are the unsuitable soil removal recommendations for the onsite geologic units below the proposed future maintenance building and parking lot. Removal bottoms should be observed by the Project Geotechnical Consultant to make a final determination that suitable, competent soils have been exposed. Removals should be completed as per Plate G‐1 and G‐2 (Appendix E). In general, removals shall expose competent Pauba Formation. Existing concrete should be removed prior to the placement of engineered fill. The demolished concrete may be incorporated into compacted, engineered fills after it is crushed to a maximum size of six Project Number 1‐0502 Page 12 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. (6) inches. Prior to placement as engineered fill any protruding steel rebar should be cut from the concrete pieces and disposed of offsite. Existing asphaltic concrete should be removed prior to the placement of engineered fill. From a geotechnical perspective, this material may be incorporated into compacted, engineered fills after it is crushed to a maximum size of six (6) inches. The crushed asphalt should not be placed under structures, but rather, it can be placed in approved non‐structural areas, such as streets, parking areas or open space. These recommendations should be verified by the environmental consultant. 6.1.2.1 Future Maintenance Building The highly weathered portions of the Pauba Formation onsite are not suitable for the support of proposed structures and should be removed and recompacted to project specifications prior to the placement of compacted fill. It is anticipated that removal recompaction depths in this unit will be approximately three (3) feet in depth. 6.1.2.2 Parking Lot For fill areas in parking lots/streets, in general, a minimum removal and recompaction of the upper two (2) feet is recommended, however all undocumented artificial fill shall be removed and recompacted. For cuts greater than two (2) feet in street areas, removals are not required. For cuts less than two (2) feet, the two (2) foot removal and recompaction applies. Project Number 1‐0502 Page 13 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.1.3 Over‐Excavation of Building Pads 6.1.3.1 Cut/Fill Transition Pads Where cut/fill transitions occur across building pads, Alta recommends that the cut and shallow fill portions be over‐ excavated and replaced with compacted fill in order to provide uniform bearing conditions. The depth of the over‐excavation should provide a minimum of three (3) feet of fill beneath the building and sufficiently deep to provide a minimum thickness of 1/3 of the maximum fill thickness beneath the building envelop, as shown on Plate G‐16 (Appendix E). The undercuts should be extended at least five (5) feet outside of perimeter footings. The proposed undercuts should be graded such that a gradient of at least one (1) percent is maintained towards deeper fill areas or toward the front of the pad. The final extent of the undercut should be verified in the field during grading. Replacement fills should be compacted to project specifications as discussed in Section 6.2.1. 6.1.3.2 Cut Pads Alta recommends that the cut pads should be over‐excavated and replaced with compacted fill in order to facilitate improvement construction. The depth of the over‐excavation should provide a minimum of three (3) feet of fill beneath the building pad. The undercuts should be extended at least five (5) outside of perimeter footings. The proposed undercuts should be graded such that a gradient of at least one (1) percent is maintained towards the front of the pad or toward deeper fill areas if present. Project Number 1‐0502 Page 14 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. The final extent of the undercut should be verified in the field during grading. Replacement fills should be compacted to project specifications as discussed in Section 6.2.1. 6.2 General Earthwork Recommendations 6.2.1 Compaction Standards All fill and processed natural ground shall be compacted to a minimum relative compaction of 90 percent, as determined by ASTM Test Method: D‐1557. Fill material should be moisture conditioned to optimum moisture or above, and as generally discussed in Alta’s Earthwork Specification Section presented in Appendix D. Compaction shall be achieved with the use of sheepsfoot rollers or similar kneading type equipment. Mixing and moisture conditioning will be required in order to achieve the recommended moisture conditions. 6.2.2 Groundwater/Seepage It is anticipated that groundwater will not be encountered during grading. It is possible that perched water conditions could be encountered in areas depending on the time of year construction occurs. 6.2.3 Documentation of Removals All removal/over‐excavation bottoms should be observed and approved by the project Geotechnical Consultant prior to fill placement. Consideration should be given to surveying the removal bottoms and undercuts after approval by the geotechnical consultant and prior to the placement of fill. Staking should be provided in order to verify undercut locations and depths. Project Number 1‐0502 Page 15 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.2.4 Treatment of Removal Bottoms At the completion of removals/over‐excavation, the exposed removal bottom should be ripped to a minimum depth of eight (8) inches, moisture‐conditioned to above optimum moisture content and compacted in‐place to the project standards. 6.2.5 Fill Placement After removals, scarification, and compaction of in‐place materials are completed, additional fill may be placed. Fill should be placed in eight‐ inch bulk maximum lifts, moisture conditioned to optimum moisture content or above, compacted and tested as grading/construction progresses until final grades are attained. 6.2.6 Moisture Content The moisture content of the upper in‐situ soils varies, as shown on the boring logs in Appendix B. Moisture conditioning will be required during grading to achieve optimum or above conditions. 6.2.7 Mixing Mixing of materials may be necessary to prevent layering of different soil types and/or different moisture contents. The mixing should be accomplished prior to and as part of compaction of each fill lift. 6.2.8 Import Soils Import soils, if necessary, should consist of clean, structural quality, compactable materials similar to the on‐site soils and should be free of trash, debris or other objectionable materials. The project Geotechnical Consultant should be notified not less than 72 hours in advance of the locations of any soils proposed for import. Import sources should be sampled, tested, and approved by the project Geotechnical Consultant at the source prior to the importation of the soils to the site. The project Project Number 1‐0502 Page 16 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. Civil Engineer should include these requirements on plans and specifications for the project. 6.2.9 Utility Trenches 6.2.9.1 Excavation Utility trenches should be supported, either by laying back excavations or shoring, in accordance with applicable OSHA standards. In general, existing site soils are classified as Soil Types "B" and “C” per OSHA standards. Upon completion of the recommended removals and re‐compaction, the artificial fill will be classified as Soil Type "B". The Project Geotechnical Consultant should be consulted if geologic conditions vary from what is presented in this report. 6.2.9.2 Backfill Trench backfill should be compacted to at least 90 percent of maximum dry density as determined by ASTM D‐1557. Onsite soils will not be suitable for use as bedding material but will be suitable for use in backfill provided oversized materials are removed. No surcharge loads should be imposed above excavations. This includes spoil piles, lumber, concrete trucks, or other construction materials and equipment. Drainage above excavations should be directed away from the banks. Care should be taken to avoid saturation of the soils. Compaction should be accomplished by mechanical means. Jetting of native soils will not be acceptable. Under‐slab trenches should also be compacted to project specifications. If select granular backfill (SE > 30) is used, compaction by flooding will be acceptable. Project Number 1‐0502 Page 17 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.2.10 Fill Slope Construction Fill slopes should be overfilled to an extent determined by the contractor, but not less than two (2) feet measured perpendicular to the slope face, so that when trimmed back to the compacted core a minimum 90 percent relative compaction is achieved. Compaction of each fill lift should extend out to the temporary slope face. Back‐rolling during mass filling at intervals not exceeding four (4) feet in height is recommended, unless more extensive overfilling is undertaken. As an alternative to overfilling, fill slopes may be built to the finish slope face in accordance with the following recommendations:  Compaction of each fill lift should extend to the face of the slopes.  Back‐rolling during mass grading should be undertaken at intervals not exceeding four (4) feet in height. Back‐rolling at more frequent intervals may be required.  Care should be taken to avoid spillage of loose materials down the face of any slopes during grading. Spill fill will require complete removal prior to compaction, shaping, and grid rolling.  At completion of mass filling, the slope surface should be watered, shaped, and compacted by track walking with a D‐8 bulldozer, or equivalent, such that compaction to project standards is achieved to the slope face. Proper seeding and planting of the slopes should follow as soon as practical to inhibit erosion and deterioration of the slope surfaces. Proper moisture control will enhance the long‐term stability of the finish slope surface. Project Number 1‐0502 Page 18 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 6.2.11 Backcut Stability Temporary backcuts, if required during unsuitable soil removals, should be made no steeper than 1:1 without review and approval of the geotechnical consultant. Flatter backcuts may be necessary where geologic conditions dictate and where minimum width dimensions are to be maintained. Care should be taken during remedial grading operations in order to minimize risk of failure. Should failure occur, complete removal of the disturbed material will be required. In consideration of the inherent instability created by temporary construction backcuts for removals, it is imperative that grading schedules are coordinated to minimize the unsupported exposure time of these excavations. Once started, these excavations and subsequent fill operations should be maintained to completion without intervening delays imposed by avoidable circumstances. In cases where five‐day workweeks comprise a normal schedule, grading should be planned to avoid exposing at‐grade or near‐grade excavations through a non‐work weekend. Where improvements may be affected by temporary instability, either on or offsite, further restrictions such as slot cutting, extending work days, implementing weekend schedules, and/or other requirements considered critical to serving specific circumstances may be imposed. 7.0 DESIGN CONSIDERATIONS 7.1 Structural Design It is anticipated that a maintenance structure may be constructed onsite. It is anticipated that the majority of onsite soils will possess "low" to "medium" expansion potential when tested in general accordance with ASTM Test Method Project Number 1‐0502 Page 19 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. D: 4829. Final slab and foundation design recommendations should be made based upon specific structure sitings and loading conditions. Preliminary design recommendations for the proposed structures are presented below. These parameters shall be verified as design of the project progresses. Table 7‐1 Foundation/Slab Design Parameters* Allowable Bearing 2000 lbs/ft2 Lateral Bearing 250 lbs/ft2 at a depth of 12 inches plus 250 lbs/ft2 for each additional 12 inches of embedment to a maximum of 2000 lbs/ft2. Sliding Coefficient 0.35 Settlement Static Settlement ‐ 0.50 inches in 40 feet Dynamic Settlement – 0.50 inches in 40 feet Modulus of Subgrade Reaction 150 pci Design Expansion Potential Medium Design Plasticity Index 20 Under‐Slab Requirement See Section 7.2 Slab Subgrade Moisture Minimum of 120 percent of optimum moisture to a depth of 12‐inches prior to placing concrete. *These values may be increased as allowed by Code to resist transient loads such as wind or seismic. Building code and structural design considerations may govern depth and reinforcement requirements and should be evaluated. 7.2 Moisture Barrier A moisture and vapor retarding system should be placed below the slabs‐on‐ grade in portions of the structure considered to be moisture sensitive and should be capable of effectively preventing the migration of water and reducing the transmission of water vapor to acceptable levels. Historically, a 10‐mil plastic membrane, such as Visqueen, placed between one to four inches of clean sand, has been used for this purpose. The use of this system or other systems can be considered, at the discretion of the designer, provided the system reduces the vapor transmission rates to acceptable levels. Project Number 1‐0502 Page 20 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 7.3 Seismic Design The site class was determined based on the subsurface investigation and published geologic maps in the area in general conformance with Chapter 20 of ASCE 7‐16. Based on density of the relatively shallow underlying Pauba Formation, a Site Class of C was selected. Utilizing this information, the computer program ATC Hazards by Location and ASCE 7‐16 criterion, the spectral response accelerations that can be utilized for the project are presented in Table 7‐2. These parameters should be verified by the structural engineer. Additional parameters should be determined by the structural engineer based on the Occupancy Category of the proposed structures. TABLE 7‐2 Seismic Ground Motion Values 2019 CBC and ASCE 7‐16 Parameter Value Site Class C Site Latitude 33.5026 Site Longitude ‐117.1109 Spectral Response Acceleration Parameter, SS 1.574 Spectral Response Acceleration Parameter, S1 0.586 Site Coefficient, Fa 1.2 Site Coefficient, Fv 1.414 MCE Spectral Response Acceleration Parameter, SMS 1.888 MCE Spectral Response Acceleration Parameter, SM1 0.828 Design Spectral Response Acceleration Parameter, SDS 1.259 Design Spectral Response Acceleration Parameter, SD1 0.552 Peak Ground Acceleration, PGAM 0.84 Project Number 1‐0502 Page 21 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 7.4 Block Walls Block walls, if used, should be embedded a minimum of 2 feet below the lowest adjacent grade. Construction joints (not more than 20 feet apart) should be included in the block wall construction. 7.5 Footing Excavations Soils from the footing excavations should not be placed in slab‐on‐grade areas unless properly compacted and tested. The excavations should be cleaned of all loose/sloughed materials and be neatly trimmed at the time of concrete placement. The Project Geotechnical Consultant should observe the footing excavations prior to the placement of concrete to determine that the excavations are founded in suitably compacted material. 7.6 Exterior Slabs and Walkways Exterior concrete slabs and walkways should be designed and constructed in consideration of the following recommendations. 7.6.1 Subgrade Compaction The subgrade below exterior concrete slabs should be compacted to a minimum of 90 percent relative compaction as determined by ASTM Test Method: D 1557. 7.6.2 Subgrade Moisture The subgrade below concrete slabs should be moisture conditioned to a minimum of 110 percent of optimum moisture (low expansion) prior to concrete placement or 120 percent of optimum moisture (medium expansion) prior to concrete placement. 7.6.3 Concrete Slab Thickness Concrete flatwork and driveways should be designed utilizing four‐inch minimum thickness. Project Number 1‐0502 Page 22 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 7.6.4 Concrete Slab Reinforcement Utilization of reinforcement for flatwork and driveways is subject to a cost/benefit analysis. Reinforcement will decrease the amount of cracking that may occur in flatwork, however, planning for occasional repairs may be more cost effective. Utilizing closely spaced control joints is likely more cost‐effective than utilizing reinforcement. The majority of the soils onsite are classified as very low to medium in expansion potential. Consideration should be given to reinforcing flatwork with irregular (non‐square/rectangular) shapes or flatwork underlain by medium expansive soils. Reinforcement may consist of 6x6 W.14/W1.4 welded wire mesh or and equivalent section of rebar. 7.6.5 Control Joints Weakened plane joints should be installed on walkways at intervals of approximately eight feet (maximum) or less. Exterior slabs should be designed to withstand shrinkage of the concrete. 7.7 Concrete Design As stated in Section 5.1.6, negligible concentrations of sulfates were detected in the onsite soils. Therefore, the use of sulfate resistant concrete is not required per ACI 318‐14 at this time. Post‐grading conditions should be evaluated, and final recommendations made at that time. 7.8 Corrosion Based on preliminary testing, the onsite soils are not considered corrosive to buried metal objects per Caltrans standards. Buried ferrous metals should be protected against the effects of corrosive soils in accordance with the manufacturer’s recommendations. Typical measures may include using non‐ corrosive backfill, protective coatings, wrapping, plastic pipes, or a combination Project Number 1‐0502 Page 23 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. of these methods. A corrosion engineer should be consulted if specific design recommendations are required by the improvement designer. Per ACI 318‐14, an exposure class of C1 would be applicable to metals encased in concrete (rebar in footings) due to being exposed to moisture from surrounding soils. Per Table 19.3.2.1 of ACI 318‐14, the requirements for concrete with an exposure class of C1 are a minimum compressive strength of 2500 psi and a maximum water‐soluble chloride ion content in concrete of 0.30 (percent by weight of cement). 7.9 Pavement Design Pavement sections for the proposed streets/parking lots shall be designed based on laboratory testing conducted on samples taken from the soil subgrade. Based on an assumed R‐Value of 20, the pavement may be designed utilizing the sections presented in Table 7‐3. These sections should be verified upon the completion of grading, based on R‐Value testing. The ultimate pavement section design for public streets is under the County of Riverside’s purview. Table 7‐3 Preliminary Pavement Sections Traffic Index Pavement Section Options OR 5.0 3‐inch AC on 7.5‐inch AB 4‐inch AC on 6‐inch AB AC‐Asphalt Concrete AB‐Caltrans Class II Base Construction of the streets should be accomplished in accordance with the current criteria of the County of Riverside. Prior to the placement of base material, the subgrade should be suitably moisture conditioned, processed and compacted to a minimum 95 percent of the laboratory maximum density (ASTM: D 1557) to at least twelve (12) inches below subgrade. After subgrade compaction, the exposed grade should then be "proof"‐rolled with heavy equipment to ensure the grade does not "pump" and is verified as non‐yielding. Project Number 1‐0502 Page 24 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. Aggregate base material should be placed on the compacted subgrade and compacted in‐place to a minimum 95 percent of the laboratory standard obtained per ASTM: D 1557. 7.10 Site Drainage Positive drainage away from the proposed structures should be provided and maintained. Roof, pad, and lot drainage should be collected and directed away from the structures toward approved disposal areas through drainage terraces, gutters, down drains, and other devices. Design fine grade elevations should be maintained through the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures. 7.11 Deepened Footings and Setbacks It is generally recognized that improvements constructed in proximity to properly constructed slopes can, over a period of time, be affected by natural processes including gravity forces, weathering of surficial soils and long term (secondary) settlement. Most building codes, including the California Building Code (CBC), require that structures be setback or footings deepened, where subject to the influence of these natural processes. For the subject site, where foundations for residential structures are to exist in proximity to slopes, the footings should be embedded to satisfy the requirements presented in the following figure. Project Number 1‐0502 Page 25 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. H H/2, need not be more than 15 feet H/2 when H < 30 feet, need not exceed 10 feet, but not less than 5 feet. H/3 when H >30 feet, need not exceed 40 feet.  Consideration of these natural processes should be undertaken in the design and construction of other improvements. Homeowners are advised to consult with qualified geotechnical engineers, designers, and contractors in the design and construction of future improvements. Each lot and proposed improvement should be evaluated in relation to the specific site conditions, accounting for the specific soil conditions. 8.0 LOT MAINTENANCE Ongoing maintenance of the improvements is essential to the long‐term performance of structures. The following recommendations should be implemented. 8.1 Lot Drainage Roof, pad and lot drainage should be collected and directed away from structures and slopes and toward approved disposal areas. Design fine grade elevations should be maintained throughout the life of the structure or if design fine grade elevations are altered, adequate area drains should be installed in order to provide rapid discharge of water, away from structures and slopes. Owners should be made aware that they are responsible for maintenance and cleaning of all drainage terraces, down drains, and other devices that have been installed to promote structure and slope stability. Project Number 1‐0502 Page 26 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. 8.2 Burrowing Animals Owners should undertake a program for the elimination of burrowing animals. 9.0 FUTURE PLAN REVIEWS This report represents a geotechnical review of the site. As the project design for the project progresses, site specific geologic and geotechnical issues should be considered in the design and construction of the project. Consequently, future plan reviews may be necessary. These reviews may include reviews of:  Grading Plans  Foundation Plans  Utility Plans These plans should be forwarded to the project Geotechnical Consultant for review. 10.0 CLOSURE 10.1 Geotechnical Review For the purposes of this report, multiple working hypotheses were established for the project, utilizing the available data and the most probable model is used for the analysis. Future information collected during the proposed grading operations is intended to evaluate the hypothesis and as such, some of the assumptions summarized in this report may need to be changed. Some modifications of the grading recommendations may become necessary, should the conditions encountered in the field differ from the conditions hypothesized in this report. Plans and sections of the project specifications should be reviewed by Alta to evaluate conformance with the intent of the recommendations contained in this report. If the project description or final design varies from that described in herein, Alta must be consulted regarding the applicability of the recommendations contained herein and whether any changes are required. Alta Project Number 1‐0502 Page 27 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. accepts no liability for any use of its recommendations if the project description or final design varies and Alta is not consulted regarding the alterations. 10.2 Limitations This report is based on the following: 1) the project as presented on the attached plan; 2) the information obtained from Alta's laboratory testing included herein; and 3) from the information presented in the referenced reports. The findings and recommendations are based on the results of the subsurface investigation, laboratory testing, and office analysis combined with an interpolation and extrapolation of conditions between and beyond the subsurface excavation locations. However, the materials adjacent to or beneath those observed may have different characteristics than those observed, and no precise representations are made as to the quality or extent of the materials not observed. The results reflect an interpretation of the direct evidence obtained. Work performed by Alta has been conducted in a manner consistent with the level of care and skill ordinarily exercised by members of the geotechnical profession currently practicing in the same locality under similar conditions. No other representation, either expressed or implied, and no warranty or guarantee is included or intended. The recommendations presented in this report are based on the assumption that an appropriate level of field review will be provided by a geotechnical consultant who is familiar with the design and site geologic conditions. That field review shall be sufficient to confirm that geotechnical and geologic conditions exposed during grading are consistent with the geologic representations and corresponding recommendations presented in this report. The conclusions and recommendations included in this report are applicable to the specific design of this project as discussed in this report. They have no Project Number 1‐0502 Page 28 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. applicability to any other project or to any other location and any and all subsequent users accept any and all liability resulting from any use or reuse of the data, opinions, and recommendations without the prior written consent of Alta. Alta has no responsibility for construction means, methods, techniques, sequences, procedures, safety precautions, programs in connection with the construction, acts or omissions of the CONTRACTOR or any other person performing any of the construction, or for the failure of any of them to carry out the construction in accordance with the final design drawings and specifications. ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX A REFERENCES Project Number 1‐0502 Page A‐1 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX A References Alta California Geotechnical, Inc., 2015, Geotechnical Investigation, Linfield Property, Tract 36098‐1, Parcels 1 through 3, and Tract 36098‐2, Parcel 1, City of Temecula, California dated June 15, 2015 (Project Number 1‐0155A). Alta California Geotechnical, Inc., 2015, Geotechnical Investigation, Eastern Portion of the Linfield Property, A Portion of Tract 36098‐3, City of Temecula, California dated June 15, 2015 (Project Number 1‐0155). California Code of Regulations, 2022, California Building Code, Title 24, Part 2, Volume 2, Based on the 2018 International Building Code, Effective Date January 1, 2023. California Department of Water Resources, 2023, online information: http://www.water.ca.gov/waterdatalibrary/index.cfm. California Department of Transportation (Caltrans), 2022, Caltrans Geotechnical Manual, published March, 2022. California Geological Survey, 2018, Earthquake Fault Zones, A Guide For Government Agencies, Property Owners/Developers, and Geoscience Practitioners for Assessing Fault Rupture Hazards in California, Special Publication 42, revised 2018. Historic Aerials, 2023, www.historicaerials.com, by NETROnline, Copyright 1999‐2020, accessed October 2023. Jennings, C.W., and Bryant, W.A., 2010, Fault Activity Map of California: California Geological Survey Geologic Data Map No. 6, map scale 1:750,000. Jennings, C. W., and Bryant, W.A., 2010, An explanatory text to accompany the 1:750,000 scale fault and geologic map of California: California Division of Mines and Geology, special publication 42, revised 1985, 24 p. Jennings, C. W., 1985, An explanatory text to accompany the 1:750,000 scale fault and geologic maps of California: California Division of Mines and Geology, Bulletin 201, 197 p. Morton, D.M., Kennedy, M.P., Bovard, K.R., and Burns, Diane, 2003, Geologic map and digital database of the Bachelor Mountain 7.5' quadrangle, Riverside County, California, U.S. Geological Survey, Open‐File Report OF‐2003‐103, 1:24,000. Riverside County RCIT, 2023, https://gis1countyofriverside.us/html5viewer/?viewer=mmc_public Romanoff, Melvin, 1989, Underground Corrosion, NBS Circular 579, Reprinted by NACE, Houston, TX, 1989. Project Number 1‐0502 Page A‐2 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. U.S. Geological Survey, 2008, National Seismic Hazards Maps – Source Parameters, http://geohazards.usgs.gove/cfusion/hazfaults_2008_search/query_maine.cfm ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX B Subsurface Investigation Project Number 1‐0502 Page B‐1 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX B Subsurface Investigation Alta's subsurface investigation consisted of excavating, logging, and sampling five (5) hollow‐ stem auger borings. Details of the subsurface investigation are presented in Table B‐1. The approximate locations of the exploratory excavations are shown on the accompanying plan (Plate 1) and the Geotechnical Logs are attached. TABLE B‐1 SURFACE INVESTIGATION DETAILS Equipment Range of Depths Sampling Methods Sample Locations Hollow‐ Stem Auger Up to 25 feet 1. Bulk 2. Ring or SPT 1. Bulk‐Select Depth 2. Ring‐Every 2.5 to 5‐ft UNIFIED SOI L CLASSIFIICATION SYSTEM Major Divisions lfl tr Description Major Divisions an tr Coarse Grained Soils N4ore than 50% retained on No 200 steve Gravel and Sravelly Soils han 50% frachon relained on No, 4 'l ts* ,-l* EIF GW Well-graded grcvels or gravel sand mixtures, little or no fines Fine (lrained isoils l\lore than Silts And Clays LL,<50 n ML Inorganic silts and very fine sands, rock flour, silty or clayey fine sands or clavev silts with slioht olasticitv GP Poorly-graded gravels or gravel sand mixture, little or no fines CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean claysSilty gravels, gravel-sand-silt mixtures OL Organic silts and organic silt-clays of low plasticity Clayey gravels, gravel-sand-clay mixtures Silts And Clays LL,<50 MF Inorganic silts, micaceous or diatomaceous fine or silty soils, elastic siltsSand and Sandy Soils than 50% fraclion Passes on No, 4 i'+. 3_'.JV! Well-graded sands or gravelly sands, little or no fines on No 200 steve VH Inorganic clays of high plasticity, fat claysSP Poorly-graded sands or gravelly sands, little or no fines SM Silty sands, sarrd-silt mixtures OF Organic clays of medium to high plasticity sc Clayey sands, and-clay mixtures Highly Organic Soils PT Peat and other highly organic soils BoUNDARY CLASSIFICATIoN: Soils possessing characteristics of two groups are designated by combinations of group symbols PARTICLE SIZ:E LIMITS U.S. STANDA,RD SiERIES SIEVE 200 40 10 4 CLEAR SQUARE SIEVE OPENINGS 3t4" 3,, ,t2" LABORATORY TESTS Symbol Tesl DS DSR cc)N SA MAX RV EI SE AL CHEM HY Direct Shear Direct Shear (Remolded) Sieve Analysis Maximum Density Resistance (R) Value Expansion Index Sand Equivalent Atterberg Limits Chemical Analysis Hydrometer Analysis SOIL MOISTURE SIZE PROPORTIONS Trace - <5% Few-5to10% Some - 15 to 25% Increasing \/isual Moisture Content Silts an0 Clays Sand Gravel Cobbles Boulders Fine Medium Coarsi€r Fine Coarse RELATIVE DENSITY Sands and Gravels Blows/Foot (SPT) Very Loose Loose Medium Dense Dense Very Dense <4 4-10 11-30 31 -50 >50 CON SI STENCY C IASSI FI CATI ON Silts and Clays Criteria Very Soft Soft Firm stiff Very Stiff Thumb penetrates soil >1 in. Thumb penetrates soil 1 in, Thumb penetrates soil 1/4 in Readily indented with thumbnail Thumbnail will not indent soil HARDNESS KEY TO EXPLORATORY BORING LOGS} ,n /L>//J, ALTA CALIFORNTA GEOTECHNTCAL tNC. /\ PI-ATE B TOPSOIL: SILTY SAND, fine grained, brown, dry, medium dense PAUBA FORMATION (Qp): SANDY CLAY, reddish brown, slightly moist, firm @5.0 ft. CLAYEY SAND, medium grained, white brown, moist, very dense @10.0 ft. SAND, medium grained, brown, moist, very dense, trace clay @15.0 ft. fine grained, white brown, dense @15.5 ft. CLAY, reddish brown, moist, firm @20.5 ft. SAND, fine grained, greenish brown, moist, very dense, trace clay TOTAL DEPTH 21.0 FEET GROUNDWATER NOT ENCOUNTERED NO CAVING OBSERVED R R R R R 29 70 83 47 34/50 for 5" 7.0 8.6 10.0 14.4 11.6 47 60 86 98 83 119 120 126 119 121 SM CL SC SP CL SP 5 10 15 20 TYPE OF DRILL RIG DRILLER SA T - CO N T ( % ) MO I S T U R E 10/19/23 (% ) UR A T I O N DATE STARTED 10/19/23 1220 1215 1210 1205 1200 GEOTECHNICAL DESCRIPTION OT H E R SA M P L E EL E V DE N S I T Y DR Y ( p c f ) BORING DESIG. DROP DRIVE WT. GW DEPTH (FT) PROJECT NAME DATE FINISHED YH DE P T H VARIES* Linfield Christian School TE S T S S SPT (SPLIT SPOON) SAMPLE R RING (DRIVE) SAMPLE SAMPLE TYPES: SHEET NOTE LOGGED BY GR O U P J: JOINTING B: BEDDING S: SHEAR C: CONTACT F: FAULT RS: RUPTURE SURFACE 1-0502 GROUNDWATER SEEPAGE (F e e t ) PROJECT NO. GEOTECHNICAL BORING LOG GROUND ELEV. 8" Hollow Stem Auger 2R SY M B O L LI T H O L O G Y BL O W S T TUBE SAMPLEB BULK SAMPLE TY P E 1 OF 1 12 in. B-11220 Alta California Geotechnical, Inc. P.N. 1-0502 PLATE B-1 TOPSOIL: SILTY SAND, fine grained, brown, dry, medium dense PAUBA FORMATION (Qp): SAND, fine grained, brown, slightly moist, very dense @2.5 ft. trace clay @5.0 ft. SILTY CLAY, brown, moist, firm @10.0 ft. SAND, medium grained, gray tan, slightly moist, very dense @15.0 gray brown @20.0 ft. gray tan, trace clay TOTAL DEPTH 21.0 FEET GROUNDWATER NOT ENCOUNTERED NO CAVING OBSERVED R R R R R 61 52 92 30/50 for 6" 65 10.1 16.7 5.4 5.5 5.8 54 89 33 40 34 111 110 116 121 114 SM SP CL SP 5 10 15 20 TYPE OF DRILL RIG DRILLER SA T - CO N T ( % ) MO I S T U R E 10/19/23 (% ) UR A T I O N DATE STARTED 10/19/23 1220 1215 1210 1205 1200 GEOTECHNICAL DESCRIPTION OT H E R SA M P L E EL E V DE N S I T Y DR Y ( p c f ) BORING DESIG. DROP DRIVE WT. GW DEPTH (FT) PROJECT NAME DATE FINISHED YH DE P T H VARIES* Linfield Christian School TE S T S S SPT (SPLIT SPOON) SAMPLE R RING (DRIVE) SAMPLE SAMPLE TYPES: SHEET NOTE LOGGED BY GR O U P J: JOINTING B: BEDDING S: SHEAR C: CONTACT F: FAULT RS: RUPTURE SURFACE 1-0502 GROUNDWATER SEEPAGE (F e e t ) PROJECT NO. GEOTECHNICAL BORING LOG GROUND ELEV. 8" Hollow Stem Auger 2R SY M B O L LI T H O L O G Y BL O W S T TUBE SAMPLEB BULK SAMPLE TY P E 1 OF 1 12 in. B-21220 Alta California Geotechnical, Inc. P.N. 1-0502 PLATE B-2 ALLUVIUM(Qal): SILTY SAND, medium grained, brown, dry, loose PAUBA FORMATION (Qp): SILTY SAND, fine grained, brown, moist, very dense, trace clay @5.0 ft. dark brown, slightly moist, dense, trace carbonates @10.0 ft. SAND, medium grained, white gray brown, slightly moist, very dense, trace pebbles, trace gravel @15.0 ft. pink tan, slightly moist, very dense, trace pebbles @20.5 ft. SANDY CLAY, greenish brown, moist, firm, trace orange mottling TOTAL DEPTH 21.0 FEET GROUNDWATER NOT ENCOUNTERED NO CAVING OBSERVED R R R R R 12/38/50 for 4" 33 35/38/50 for 5" 57 25/45 9.2 6.7 4.9 9.5 9.3 78 41 47 42 71 CON, HY 126 115 130 104 123 SM SM SP CL 5 10 15 20 TYPE OF DRILL RIG DRILLER SA T - CO N T ( % ) MO I S T U R E 10/19/23 (% ) UR A T I O N DATE STARTED 10/19/23 1220 1215 1210 1205 1200 GEOTECHNICAL DESCRIPTION OT H E R SA M P L E EL E V DE N S I T Y DR Y ( p c f ) BORING DESIG. DROP DRIVE WT. GW DEPTH (FT) PROJECT NAME DATE FINISHED YH DE P T H VARIES* Linfield Christian School TE S T S S SPT (SPLIT SPOON) SAMPLE R RING (DRIVE) SAMPLE SAMPLE TYPES: SHEET NOTE LOGGED BY GR O U P J: JOINTING B: BEDDING S: SHEAR C: CONTACT F: FAULT RS: RUPTURE SURFACE 1-0502 GROUNDWATER SEEPAGE (F e e t ) PROJECT NO. GEOTECHNICAL BORING LOG GROUND ELEV. 8" Hollow Stem Auger 2R SY M B O L LI T H O L O G Y BL O W S T TUBE SAMPLEB BULK SAMPLE TY P E 1 OF 1 12 in. B-31220 Alta California Geotechnical, Inc. P.N. 1-0502 PLATE B-3 TOPSOIL: SILTY SAND, fine grained, brown, dry, medium dense PAUBA FORMATION (Qp): CLAYEY SAND, fine grained, reddish brown, moist, very dense, some roots in top 2.5 feet @5.0 ft. CLAYEY SILT, brown, slightly moist, firm, trace sand @10.0 ft. CLAYEY SAND, medium grained, brown, moist, very dense, trace silt @15.0 ft. SAND, medium grained, gray tan, slightly moist, very dense 20.0 ft. trace pebbles TOTAL DEPTH 21.0 FEET GROUNDWATER NOT ENCOUNTERED NO CAVING OBSERVED R R R R R 7/30/50 for 6" 30/50 for 5" 30/50 for 3" 33/50 for 4" 30/40/50 for 5" 8.4 6.0 7.3 5.3 4.5 82 51 75 26 29 130 126 131 108 118 SM SC ML SC SP 5 10 15 20 TYPE OF DRILL RIG DRILLER SA T - CO N T ( % ) MO I S T U R E 10/19/23 (% ) UR A T I O N DATE STARTED 10/19/23 1220 1215 1210 1205 1200 GEOTECHNICAL DESCRIPTION OT H E R SA M P L E EL E V DE N S I T Y DR Y ( p c f ) BORING DESIG. DROP DRIVE WT. GW DEPTH (FT) PROJECT NAME DATE FINISHED YH DE P T H VARIES* Linfield Christian School TE S T S S SPT (SPLIT SPOON) SAMPLE R RING (DRIVE) SAMPLE SAMPLE TYPES: SHEET NOTE LOGGED BY GR O U P J: JOINTING B: BEDDING S: SHEAR C: CONTACT F: FAULT RS: RUPTURE SURFACE 1-0502 GROUNDWATER SEEPAGE (F e e t ) PROJECT NO. GEOTECHNICAL BORING LOG GROUND ELEV. 8" Hollow Stem Auger 2R SY M B O L LI T H O L O G Y BL O W S T TUBE SAMPLEB BULK SAMPLE TY P E 1 OF 1 12 in. B-41220 Alta California Geotechnical, Inc. P.N. 1-0502 PLATE B-4 TOPSOIL: SILTY SAND, fine grained, brown, dry, medium dense PAUBA FORMATION (Qp): SILTY SAND, fine grained, brown tan, moist, very dense @5.0 ft. trace clay @10.0 ft. SAND, medium grained, gray white tan, slightly moist, very dense, trace carbonates TOTAL DEPTH 21.0 FEET GROUNDWATER NOT ENCOUNTERED NO CAVING OBSERVED R R R R R 10/28/50 for 3" 50 for 6" 27/50 for 5" 41/50 for 5" 30/40/50 for 5" 8.7 6.9 5.5 6.6 7.5 64 59 35 40 41 CON, HY 122 126 117 115 112 SM SM SP 5 10 15 20 TYPE OF DRILL RIG DRILLER SA T - CO N T ( % ) MO I S T U R E 10/19/23 (% ) UR A T I O N DATE STARTED 10/19/23 1220 1215 1210 1205 1200 GEOTECHNICAL DESCRIPTION OT H E R SA M P L E EL E V DE N S I T Y DR Y ( p c f ) BORING DESIG. DROP DRIVE WT. GW DEPTH (FT) PROJECT NAME DATE FINISHED YH DE P T H VARIES* Linfield Christian School TE S T S S SPT (SPLIT SPOON) SAMPLE R RING (DRIVE) SAMPLE SAMPLE TYPES: SHEET NOTE LOGGED BY GR O U P J: JOINTING B: BEDDING S: SHEAR C: CONTACT F: FAULT RS: RUPTURE SURFACE 1-0502 GROUNDWATER SEEPAGE (F e e t ) PROJECT NO. GEOTECHNICAL BORING LOG GROUND ELEV. 8" Hollow Stem Auger 2R SY M B O L LI T H O L O G Y BL O W S T TUBE SAMPLEB BULK SAMPLE TY P E 1 OF 1 12 in. B-51220 Alta California Geotechnical, Inc. P.N. 1-0502 PLATE B-5 ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX B‐1 Previous Subsurface Investigation (Alta, 2016) (Alta, 2015) ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX C Laboratory Testing Project Number 1‐0502 Page C‐1 November 15, 2023 ALTA CALIFORNIA GEOTECHNICAL, INC. LABORATORY TESTING The following laboratory tests were performed on a representative sample in accordance with the applicable latest standards or methods from the ASTM, California Building Code (CBC) and California Department of Transportation. Classification Soils were classified with respect to the Unified Soil Classification System (USCS) in accordance with ASTM D‐2487 and D‐2488. Particle Size Analysis Modified hydrometer testing was conducted to aid in classification of the soil. The results of the particle size analysis are presented in Table C. Expansion Index Tests One (1) expansion index test was performed to evaluate the expansion potential of typical on‐ site soil. Testing was carried out in general conformance with ASTM Test Method D‐4829. The results are presented in Table C. Consolidation Tests Consolidation testing was performed on one (1) relatively “undisturbed” soil samples at their natural moisture content in accordance with procedures outlined in ASTM D‐2435. The sample was placed in a consolidometer and loads were applied incrementally in geometric progression. The sample (2.42‐inches in diameter and 1‐inch in height) was permitted to consolidate under each load increment until the slope of the characteristic linear secondary compression portion of the thickness versus log of time plot was apparent. The percent consolidation for each load cycle was recorded as the ratio of the amount of vertical compression to the original 1‐inch height. The consolidation test results are shown on Plate C‐1. Chemical Analyses Chemical testing was performed on one select sample. The results of this test (sulfate content, resistivity, chloride content and pH) is presented on Table C. B-1 3 Silty Sand (Qp) SM 1 65 18 16 5 Sulf: 0.001% Chlr: 75ppm pH: 8.1, Resis: 3,811 Ohm-cm B-3 5 Silty Sand (Qoa) SM 0 76 9 15 SEE PLATE C-1 B-5 2.5 Silty Sand (Qoa) SM 0 52 31 17 OTHER TESTS REMARKS BORING DEPTH (FEET) SOIL DESCRIPTION GROUP SYMBOL DIRECT SHEAR EXPANSION INDEX UBC 18-2 MAXIMUM DENSITY (PCF) TABLE C SUMMARY OF LABORATORY TEST DATA P.N. 1-0502 OPTIMUM MOISTURE CONTENT (%) CONSOLSILT (0.075mm-0.005mm) (%) SAND (4.76mm-0.075mm) (%) PLUS NO.4 SEIVE (plus 4.76mm) (%) CLAY (minus 0.005mm) (%) Alta California Geotechnical, Inc. -2.0 -1.0 0 1.0 2.0 3.0 4.0 5.0 6.0 7.0 8.0 0.1 2 3 4 5 6 7 8 9 1 2 3 4 5 6 7 8 9 10 REMARKS: WATER ADDED AT 1.07 TSF CONSOLIDATION CURVE PE R C E N T C H A N G E I N H E I G H T PLATE C-1 COMPRESSIVE STRESS IN TSF satur. (%) 115 -200 Silty Sand (Qoa)SM boring in situ 41 group typical namessymbolsieve (%)density (pcf) 6.7 moist. (%) in situdrydepth (ft.) 5.0B-3 24 Alta California Geotechnical, Inc. P.N. 1-0502 ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX D Earthwork Specifications ALTA CALIFORNIA GEOTECHNICAL, INC. APPENDIX E Grading Details T-1Qp afu (Qp) Qp Qp B-4 P-1 T-20 B-1 0-1.5' Qal 1.5'-2.5' Qp No H2O Qal B-2 0-1' af 1'-5' Qp 5'-11' Qp No H2O Qal (Qp) afu (Qp) B-5 Qal (Qp) 0'-5.5' Qal 5.5'-6.5' Qp No H2O T-17 0'-2.5' Qp No H2O T-19 Qp afu (Qal) afu (Qp) B-3 Qp afu (Qal) PLATE 1 170 N. MAPLE STREET, STE 108, CORONA, CA 92880 TELEPHONE: (951) 509-7090 ALTA CALIFORNIA GEOTECHNICAL, INC. LEGEND Artificial Fill-Undocumented Alluvium (bracketed where buried) Pauba Formation (bracketed where buried) Geologic Contact (dotted where buried) Approximate Location of Backhoe Test Pit Approximate Location of Hollow Stem Auger Boring Approximate Location of Infiltration Test Approximate Limits of Report afu Qal H-4 P-1 T-20