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HomeMy WebLinkAboutCT 2017-0003; LA COSTA TOWN SQUARE PARCEL 3; STORM WATER QUALITY MANAGEMENT PLAN; 2019-10-12CITY OF CARLSBAD PRIORITY DEVELOPMENT PROJECT (PDP) STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) FOR LA COSTA TOWN SQUARE PARCEL 3 PUD 2017-0004 CT2017-0003 AMEND 2017 -0012 ENGINEER OF WORK: -~M::c ~ 1. 48670 PREPARED FOR: TRC RETAIL 4695 MACARTHUR COURT SUITE 700 NEWPORT BEACH, CA 92660 (949) 662-2144 PREPARED BY: HUNSAKER &ASSOCIATES 9707 WAPLES ST SAN DIEGO, CA 92121 (619) 558-4500 DATE: October 14th, 2019 RECORD COPY Initial Date NO\J 12 2019 C\TY OF CARLSBAD PLA\ ~· 11 G DIVISION TABLE OF CONTENTS Certification Page Project Vicinity Map FORM E-34 Storm Water Standard Questionnaire Site Information FORM E-36 Standard Project Requirement Checklist Summary of PDP Structural BMPs Attachment 1: Backup for PDP Pollutant Control BMPs Attachment la: DMA Exhibit Attachment lb: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment le: Harvest and Use Feasibility Screening (when applicable) Attachment ld: Categorization of Infiltration Feasibility Condition (when applicable) Attachment le: Pollutant Control BMP Design Worksheets / Calculations Attachment 2: Backup for PDP Hydromodification Control Measures Attachment 2a: Hydromodification Management Exhibit Attachment 2b: Management of Critical Coarse Sediment Yield Areas Attachment 2c: Geomorphic Assessment of Receiving Channels Attachment 2d: Flow Control Facility Design Attachment 3: Structural BMP Maintenance Thresholds and Actions Attachment 4: Single Sheet BMP (SSBMP) Exhibit Attachment 5: Geotechnical Report CERTIFICATION PAGE Project Name: LA COSTA TOWN SQUARE PARCEL 3 Project ID: PUD 2017-0004 CT2017-0003 AMEND 2017 -0012 I hereby declare that I am the Engineer in Responsible Charge of design of storm water BMPs for this project, and that I have exercised responsible charge over the design of the project as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with the requirements of the BMP Design Manual, which is based on the requirements of SDRWQCB Order No. R9-2013-0001 (MS4 Permit) or the current Order. I have read and understand that the City Engineer has adopted minimum requirements for managing urban runoff, including storm water, from land development activities, as described in the BMP Design Manual. I certify that this SWQMP has been completed to the best of my ability and accurately reflects the project being proposed and the applicable source control and site design 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 SWQMP by the City Engineer is confined to a review and does not relieve me, as the Engineer in Responsible Charge of design of storm water BMPs for this project, of my responsibilities for project design. eer of Work's Signature, PE Number & Expiration Date Raymond L. Martin Print Name Hunsaker & Associates Company October 14th 2019 Date PROJECT VICINITY MAP CITY Y OF SAN MARCOS I I\ .---'-I PROJECT 1TE CITY OF VICINITY MAP NTS C cityof Carlsbad I INSTRUCTIONS: STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov To address post-development pollutants that may be generated from development projects, the city requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual, refer to the Engineering Standards (Volume 5). This questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to 'STANDARD PROJECT' requirements or be subject to 'PRIORITY DEVELOPMENT PROJECT' (PDP) requirements. Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the city. If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please seek assistance from Land Development Engineering staff. A completed and signed questionnaire must be submitted with each development project application. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. PROJECT INFORMATION PROJECT NAME: La Costa Town Square Parcel 3 PROJECT ID: PUD 2017-0004 CT2017-0003 AMEND 2017 -0012 ADDRESS: La Costa Ave. and Calle Timeteo APN: 223-050-73 The project is (check one): Ix! New Development D Redevelopment The total proposed disturbed area is: 250470 ft2 ( ) acres The total proposed newly created and/or replaced impervious area is: 147233 ft2 ( ) acres If your project is covered by an approved SWQMP as part of a larger development project, provide the project ID and the SWQMP # of the larger development project: Project ID PUD 2017-0004 CT2017-0003 AMEND 2017 -0012 SWQMP#: Then, go to Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city. E-34 Page 1 of 4 REV 02/16 STEP1 TO BE COMPLETED FOR ALL PROJECTS To determine if your project is a "development project", please answer the following question: YES NO Is your project LIMITED TO routine maintenance activity and/or repair/improvements to an existing building □ ~ or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for guidance)? If you answered "yes" to the above question, provide justification below then go to Step 5, mark the third box stating "my project is not a 'development project' and not subject to the requirements of the BMP manual" and complete applicant information. Justification/discussion: (e.g. the project includes only interior remodels within an existing building): If you answered "no" to the above question, the project is a 'development project', go to Step 2. STEP2 TO BE COMPLETED FOR ALL DEVELOPMENT PROJECTS To determine if your project is exempt from PDP requirements pursuant to MS4 Permit Provision E.3.b.(3), please answer the following questions: Is your project LIMITED to one or more of the following: YES NO 1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria: a) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non- erodible permeable areas; □ IBI b) Designed and constructed to be hydraulically disconnected from paved streets or roads; c) Designed and constructed with permeable pavements or surfaces in accordance with USEPA Green Streets quidance? 2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in □ IBI accordance with the USEPA Green Streets guidance? 3. Ground Mounted Solar Array that meets the criteria provided in section 1.4.2 of the BMP manual? □ [x] If you answered "yes" to one or more of the above questions, provide discussion/justification below, then go to Step 5, mark the second box stating "my project is EXEMPT from PDP ... " and complete applicant information. Discussion to justify exemption ( e.g. the project redeveloping existing road designed and constructed in accordance with the USEPA Green Street guidance): If you answered "no" to the above questions, your project is not exempt from PDP, go to Step 3. E-34 Page 2 of 4 REV 04/17 ,, -. I ' I .. To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(1 )): YES NO 1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collectively over the entire project site? This includes commercial, industrial, residential, mixed-use, !Kl □ and public development projects on public or private land. 2. Is your project a redevelopment project creating and/or replacing 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 □ [2g more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. 3. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and □ 00 refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812). 4. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the entire project site and supports a hillside development project? A hillside □ [g] development project includes development on any natural slope that is twenty-five percent or Qreater. 5. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a parking lot? A parking lot is 00 □ a land area or facility for the temporary parking or storage of motor vehicles used personally for business or for commerce. 6. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious street, road, highway, freeway or driveway surface collectively over the entire project [g] □ site? A street, road, highway, freeway or driveway is any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. 7. Is your project a new or redevelopment project that creates and/or replaces 2,500 square feet or more of impervious surface collectively over the entire site, and discharges directly to an Environmentally Sensitive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of □ [xi 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).* 8. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface that supports an automotive repair shop? An automotive repair □ Ix] shop is a facility that is categorized in any one of the following Standard Industrial Classification (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539. 9. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious area that supports a retail gasoline outlet (RGO)? This category includes □ 00 RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of 100 or more vehicles per day. 10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land 00 □ and are expected to generate pollutants post construction? 11 . Is your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of impervious surface or (2) increases impervious surface on the property by more than 10%? (CMC □ Ix] 21.203.040) If you answered "yes" to one or more of the above questions, your project is a PDP. If your project is a redevelopment project, go to step 4. If your project is a new project, go to step 5, check the first box stating "My project is a PDP ... " and complete applicant information. If you answered "no" to all of the above questions, your project is a 'STANDARD PROJECT.' Go to step 5, check the second box statinQ "My project is a 'STANDARD PROJECT' ... " and complete applicant information. E-34 Page 3 of4 REV 04/17 STEP4 TO BE COMPLETED FOR REDEVELOPMENT PROJECTS THAT ARE PRIORITY DEVELOPMENT PROJECTS (PDP) ONLY Complete the questions below regarding your redevelopment project (MS4 Permit Provision E.3.b.(2)): YES NO Does the redevelopment project result in the creation or replacement of impervious surface in an amount of less than 500/4 of the surface area of the previously existing development? Complete the percent impervious calculation below: Existing impervious area (A) = sq. ft . □ □ Total proposed newly created or replaced impervious area (B) = sq. ft. Percent impervious area created or replaced (B/A)*100 = % If you answered "yes", the structural BMPs required for PDP apply only to the creation or replacement of impervious surface and not the entire development. Go to step 5, check the first box stating "My project is a PDP .. ." and complete applicant information. If you answered "no," the structural BM P's required for PDP apply to the entire development. Go to step 5, check the check the first box stating "My project is a PDP ... " and complete aoolicant information. STEPS CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION 00 My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must prepare a storm Water Quality Management Plan (SWQMP) for submittal at time of application. □ My project is a 'STANDARD PROJECT' OR EXEMPT from PDP and must only comply with 'STANDARD PROJECT' stormwater requirements of the BMP Manual. As part of these requirements, I will submit a "Standard Project Requirement Checklist Form E-36" and incorporate low impact development strategies throughout my project. Note: For projects that are close to meeting the PDP threshold , staff may require detailed impervious area calculations and exhibits to verify if 'STANDARD PROJECT' stormwater requirements apply. D My Project is NOT a 'development project' and is not subject to the requirements of the BMP Manual. Applicant Information and Signature Box Applicant Name: Carlos Palafox Applicant Title: Senior Vice President Develoement Applicant Signature: Jt:'~ Date: 9/4/2018 V • Environmentally sensitive Areas include but are not limited to all Clean Wfl.er Act ~ction 303(d) impaired water bodies: areas des1g,ated as Areas cf Special Biologcal Sig,ificance Df the Sta:e Wa:er Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments): water bodies designa:ed wth the RARE beneficial use by the Sta:e Wa:er Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments): areas desig,ated as preserves or their equivalent under the Multi Species Conservation Program wthin th e Cities and County of San Diego: Habitat Management Plan: and any other eQ:Jivalent environmentally sensitive areas which have been identified by the Oty. This Box for Clv Use Onlv YES NO City Concurrence: □ □ By: Date: Project ID: E-34 Page 4 of4 REV 04/17 SITE INFORMATION CHECKLIST Project Summary Information Project Name La Costa Town Center Project ID PUD 2017-0004 CT2017-0003 AMEND 2017 -0012 Project Address La Costa Ave., Carlsbad, CA 92009 Assessor's Parcel Number(s) (APN(s)) 223-050-73 Project Watershed (Hydrologic Unit) Carlsbad 904 Parcel Area _L1__ Acres ( 313632 Square Feet) Existing Impervious Area (subset of Parcel Area) _O_ Acres ( 0 Square Feet) Area to be disturbed by the project (Project Area) 5.75 Acres ( 215662 Square Feet) Offsite Disturbed Area 1.00 Acres ( 43593 Square Feet) Project Proposed Impervious Area (subset of Project Area) 3.38 Acres ( 147232.8 Square Feet) Project Proposed Pervious Area (subset of Project Area) ill.... Acres ( 24829.6 Square Feet) Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project. This may be less than the Parcel Area. DescriDtlon of Existing Site Condition and Drainage Patterns Current Status of the Site (select all that apply): □ Existing development IZI Previously graded but not built out □ Agricultural or other non-impervious use □ Vacant, undeveloped/natural Description/ Additional Information: Project site was originally graded by O'Day consultants with the La Costa Town Square Existing Land Cover Includes (select all that apply): IZI Vegetative Cover □ Non-Vegetated Pervious Areas □ Impervious Areas Description/ Additional Information: Project site was originally graded out by O'Day Consultants Underlying Soil belongs to Hydrologic Soil Group (select all that apply): □ NRCS Type A □ NRCS Type B IZI NRCS Type C IZI NRCS Type D Approximate Depth to Groundwater (GW): □ GW Depth < 5 feet □ 5 feet < GW Depth < 10 feet □ 10 feet < GW Depth < 20 feet IZI GW Depth> 20 feet (not encountered) Existing Natural Hydrologic Features (select all that apply): □ Watercourses □ Seeps □ Springs □ Wetlands IZI None Description/ Additional Information: Description of Existing Site Topography and Drainage [How is storm water runoff conveyed from the site? At a minimum, this description should answer (1) whether existing drainage conveyance is natural or urban; (2) describe existing constructed storm water conveyance systems, if applicable; and (3) is runoff from offsite conveyed through the site? if so, describe]: Existing storm water runoff is from the previously mass graded site per O'Day Consultants report in August 2014. The site is divided into 2 drainage areas, the westerly and easterly. The westerly drainage originates to the north and flows southerly into 1 of 2 desilting basins. It converges with flow from the graded slope. From there flow is routed to the basin to the west via storm drains. The easterly drainage area flows similar to the westerly drainage, originating from the north and flowing south into a desilting basin. It then outflows out of a storm drain and converges with runoff that flows down the access road and is intercepted by a ditch that routes the flow into an onsite swale. Once flows discharge from the easterly basin they are routed via storm drain into an existing city owned HOPE pipe. No offsite runoff is conveyed through the site. Description of Prooosed Site Development and Drainage Patterns Project Description / Proposed Land Use and/or Activities: La Costa Town Square proposes 95 multi-family units List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): Buildings, roadways, sidewalks, parking lot List/describe proposed pervious features of the project (e.g., landscape areas): Recreational area Does the project include grading and changes to site topography? IZI Yes □No Description/ Additional Information: The site will be regraded to allow for better drainage conditions and will therefore alter existing conditions. However, peak flows discharging from the site will be reduced compared to existing conditions due to the basins which will be utilized for HMP flow-control and peak flow attenuation. Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)? ~ Yes □No Description/ Additional Information: The site will have two discharge points, one on the pad and one from the access road. The pad will drain residential, pavement, and rec. lot areas. The proposed pad also alters existing conditions as area that once drained to the south east towards the existing 30" RCP will now drain to the offsite west basin. The access road will drain pavement and landscape. Area that once drained to the south east will be re-routed to the west basin and will confluence in the same storm drain system and will discharge to the same watershed. The westerly drainage basin has enough capacity to accommodate this additional flow. Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply): ~ On-site storm drain inlets D Interior floor drains and elevator shaft sump pumps □ Interior parking garages ~ Need for future indoor & structural pest control ~ Landscape/Outdoor Pesticide Use □ Pools, spas, ponds, decorative fountains, and other water features □ Food service □ Refuse areas □ Industrial processes □ Outdoor storage of equipment or materials □ Vehicle and Equipment Cleaning □ Vehicle/Equipment Repair and Maintenance □ Fuel Dispensing Areas □ Loading Docks □ Fire Sprinkler Test Water □ Miscellaneous Drain or Wash Water ~ Plazas, sidewalks, and parking lots Identification of Receiving Water Pollutants of Concern Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): Storm water is collected and eventually discharged into the Encinitas Creek. List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs for the impaired water bodies: 303(d) Impaired Water Body Pollutant(s)/Stressor(s) TMDLs Encinitas Creek Benthic Community Effects, TMDL requirement status: TMDL Phosphorus, Selenium, Toxicity still required Identification of Project Site Pollutants Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6): Not Applicable to the Anticipated from the Also a Receiving Water Pollutant Project Site Project Site Pollutant of Concern Sediment X Nutrients Heavy Metals Organic Compounds Trash & Debris X Oxygen Demanding Substances Oil & Grease X Bacteria & Viruses Pesticides Hvdromodificatlon Management Requirements Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? C8J Yes, hydromodification management flow control structural BMPs required. □ No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. □ No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete-lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. □ No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides. Description/ Additional Information (to be provided if a 'No' answer has been selected above): Critical Coarse Sediment Yield Areas* *This Section only required if hydromodiflcation management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? C8J Yes □ No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? C8J 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite □ 6.2.2 Downstream Systems Sensitivity to Coarse Sediment □ 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite □ No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps If optional analyses were performed, what is the final result? C8J No critical coarse sediment yield areas to be protected based on verification of GLUs onsite □ Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 8 of the SWQMP. D Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit. Discussion/ Additional Information: The site is graded and has 2% slopes with disturbed habitat and sedimentary fill with underlying fine sedimentary rock. Onsite GLUs are not in the list of critical coarse sediment yield areas in Appendix H, Table H.1-3 of the BMP Manual. Onsite GLUs Based on Analysis: FSI-Unknown-1 Flow Control for Post-Project Runotr *This Section only required If hydromodlflcatlon management reaulrements apply List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit. There are 2 point of compliances (POC 1 and POC 2 on HMP map). POC 1 is from the offsite west basin and POC 2 is from the onsite basin Has a geomorphic assessment been performed for the receiving channel(s)? 1:8:1 No, the low flow threshold is 0.1Q2 (default low flow threshold) D Yes, the result is the low flow threshold is 0.1Q2 D Yes, the result is the low flow threshold is 0.3Q2 D Yes, the result is the low flow threshold is 0.SQ2 If a geomorphic assessment has been performed, provide title, date, and preparer: Discussion/ Additional Information: (optional) Other Site Requirements and Constraints When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or City codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements. The offsite west basin was previously graded during the grading of the project site and development of La Costa Town Square and under the SUSMP. Calculations will be needed to verify that there will be no net increase so that the existing downstream storm drain has adequate capacity. Optional Addltlonal Information or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed. C cicyof Carlsbad STANDARD PROJECT REQUIREMENT CHECKLIST E-36 Project Information Project Name: La Costa Town Square Parcel 3 Project ID: DWG No. or Building Permit No.: Source Control BMPs Development Services Land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See Chapter 4 and Appendix E.1 of the BMP Design Manual (Volume 5 of City Engineering Standards) for information to implement source control BMPs shown in this checklist. Answer each category below pursuant to the following. • "Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1 of the Model BMP Design Manual. Discussion/justification is not required. • "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed. • "NIA" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion/justification may be orovided. Source Control Requirement Applied? SC-1 Prevention of Illicit Discharges into the MS4 [!]Yes □No □ N/A Discussion/justification if SC-1 not implemented: SC-2 Storm Drain Stenciling or Signage [!] Yes □No 0 N/A Discussion/justification if SC-2 not implemented: SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind □Yes □No [!] N/A Dispersal Discussion/justification if SC-3 not implemented: E-36 Page 1 of 4 Revised 09/16 Source Control Reaulrement (continued) Applied? SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and □Yes D No Iii N/A Wind Dispersal Discussion/justification if SC-4 not implemented: SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal □Yes D No Iii N/A Discussion/justification if SC-5 not implemented: SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below and identify additional BMPs. (See Table in Appendix E.1 of BMP Manual for i:iuidance). Iii On-site storm drain inlets Iii Yes D No D N/A □ Interior floor drains and elevator shaft sump pumps □Yes D No Iii N/A □ Interior parking garages □Yes D No Iii N/A Iii Need for future indoor & structural pest control Iii Yes D No D NIA Iii Landscape/Outdoor Pesticide Use Iii Yes □No D N/A □ Pools, spas, ponds, decorative fountains, and other water features □Yes D No Iii N/A O Food service □Yes D No Iii N/A □ Refuse areas □Yes D No D N/A D Industrial processes □Yes D No Iii NIA □ Outdoor storage of equipment or materials D Yes D No Iii N/A D Vehicle and Equipment Cleaning □Yes □No Iii N/A □ Vehicle/Equipment Repair and Maintenance □Yes D No Iii NIA □ Fuel Dispensing Areas □Yes D No Iii N/A □ Loading Docks □Yes D No Iii N/A □ Fire Sprinkler Test Water □Yes □No Iii N/A □ Miscellaneous Drain or Wash Water □Yes □No Iii N/A Iii Plazas, sidewalks, and oarkino lots Iii Yes D No D N/A For "Yes" answers, identify the additional BMP per Appendix E.1 . Provide justification for "No" answers. Storm drain inlets: shall be periodically repainted or replaced Indoor and structural pest control: Integrated pest management to be provided to owners Landscape/outdoor pesticide use: maintain using little to no pesticides Plaza/sidewalk/parking: sweep regularly to prevent accumulation of litter and debris E-36 Page2 of 4 Revised 09/16 Site Design BMPs All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual (Volume 5 of City Engineering Standards) 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 BMPs as described in Chapter 4 and/or Appendix E.2 thru E.6 of the Model BMP Design Manual. Discussion / justification is not required. • "No" means the BMPs is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed. • "N/A" means the BMPs is not applicable at the project site because the project does not include the feature that is addressed by the BMPs (e.g., the project site has no existing natural areas to conserve). Discussion/justification may be provided. Site Design Requirement I Applied? SD-1 Maintain Natural Drainage Pathways and Hydrologic Features I □Yes I Ii! No I □ N/A Discussion/justification if SD-1 not implemented: SD-2 Conserve Natural Areas, Soils, and Vegetation I Ii! Yes I □ No I □ N/A Discussion/justification if SD-2 not implemented: SD-3 Minimize Impervious Area I Iii Yes I □ No I □ N/A Discussion/justification if SD-3 not implemented: SD-4 Minimize Soil Compaction I Ii! Yes I ONo I □ NIA Discussion/justification if SD-4 not implemented: SD-5 Impervious Area Dispersion I Iii Yes I □ No I □ N/A Discussion/justification if SD-5 not implemented: E-36 Page 3 of4 Revised 09/16 Site Deslan Reaulrement (continued) I Applied? SD-6 Runoff Collection I □Yes I Ii] No I □ N/A Discussion/justification if SD-6 not implemented: Harvest and use is infeasible according to form 1-7 SD-7 LandscapinQ with Native or DrouQht Tolerant Species I Iii Yes I □ No I D NIA Discussion/justification if SD-7 not implemented: SD-8 HarvestinQ and Using Precipitation I D Yes I Iii No I D NIA Discussion/justification if SD-8 not implemented: Harvest and use infeasible according to Form 1-7 E-36 Page4 of 4 Revised 09/16 SUMMARY OF PDP STRUCTURAL BMPS PDP Structural BMPs All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the selection process described in Chapter 5. PDPs subject to hydromodification management requirements must also implement structural BMPs for flow control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water pollutant control and flow control for hydromodification management can be achieved within the same structural BMP(s). PDP structural BMPs must be verified by the City at the completion of construction. This may include requiring the project owner or project owner's representative to certify construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must be maintained into perpetuity, and the City must confirm the maintenance (see Section 7 of the BMP Design Manual). Use this form to provide narrative description of the general strategy for structural BMP implementation at the project site in the box below. Then complete the PDP structural BMP summary information sheet for each structural BMP within the project (copy the BMP summary information page as many times as needed to provide summary information for each individual structural BMP). Describe the general strategy for structural BMP implementation at the site. This information must describe how the steps for selecting and designing storm water pollutant control BMPs presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated together or separate. Due to lack of space onsite, the project will utilize the offsite existing detention basin to the west. The basin will be modified/converted into a combined biofiltration, hydromodification, and 100 year detention facility for both the commercial site and the project. This basin has enough capacity to accommodate the additional flow that will be re-routed from the south east. Step 1: DCV Calculated using worksheet b-2.1 la: self-mitigating areas identified lb: DCV reduction not applicable to project site Step 2: Form 1-7 used to calculated harvest and use. Deemed infeasible Step 3: Infiltration is infeasible due to soil type found onsite [Continue on next page as necessary.] [Continued from previous page -This page is reserved for continuation of description of general strategy for structural BMP implementation at the site.] Step 4: BMP footprint fits. Step 4 met Step 5: This SWQMP prepared as part of step 5 Step 6: Item 1 and 2 from Table 7-1 identified as part offirst SWQMP submittal. Structural BMP Summary Information [Copy this page as needed to provide information for each individual prooosed structural BMP] Structural BMP ID No. Basin 1 DWG Sheet No. Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) (8l Biofiltration (BF-1) D 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) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: D Pollutant control only D Hydromodification control only (8l Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): Structural BMP Summary Information [Copy this nasre as needed to provide Information for each Individual pronosed structural BMP] Structural BMP ID No. BF-2 (Basin 2) DWG Sheet No. Type of structural BMP: □ Retention by harvest and use (HU-1) □ Retention by infiltration basin (INF-1) □ Retention by bioretention (INF-2) □ Retention by permeable pavement (INF-3) □ Partial retention by biofiltration with partial retention (PR-1) C8l Biofiltration (BF-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) □ Detention pond or vault for hydromodification management □ Other (describe in discussion section below) Purpose: □ Pollutant control only □ Hydromodification control only C8l Combined pollutant control and hydromodification control □ Pre-treatment/forebay for another structural BMP □ Other (describe in discussion section below) Discussion (as needed): Basin 2 is a detention basin that includes a biofiltration area that is designed to provide water quality treatment for the discharge associated with LCTS (Parcel 3). The Biofiltration area provides 6" of ponding, 18" of engineered soil, and 12" of gravel per requirements set forth in the BMP manual. Flows in the biofiltration area will pond above the required 6" and will spill over into the detention area of basin 2. The existing outlet structure associated with detention area of basin 2 has a bottom orifice height of 0.4 feet which will not be modified as the 6" of required ponding is achieved by the biofiltration area of basin 2. Attachment Sequence Attachment la ATTACHMENT 1 BACKUP FOR PDP POLLUTANT CONTROL BMPS This is the cover sheet for Attachment 1. Check which Items are Included behind this cover sheet: Contents OMA Exhibit (Required) See OMA Exhibit Checklist on the back of this Attachment cover sheet. (24"x36" Exhibit typically required) Checklist IZ! Included Attachment lb Tabular Summary of DMAs Showing IZI Included on OMA Exhibit in OMA ID matching OMA Exhibit, OMA Attachment la Attachment le Attachment ld Attachment le Area, and OMA Type (Required)* □ Included as Attachment lb, separate *Provide table in this Attachment OR on OMA Exhibit in Attachment la from OMA Exhibit Form 1-7,. Harvest and Use Feasibility IZI Included Screening Checklist (Required unless the □ Not included because the entire entire project will use infiltration BMPs) project will use infiltration BMPs Refer to Appendix B.3-1 of the BMP Design Manual to complete Form 1-7. Form 1-8, Categorization of Infiltration Feasibility Condition (Required unless the project will use harvest and use BMPs) Refer to Appendices C and D of the BMP Design Manual to complete Form 1-8. IZI Included □ Not included because the entire project will use harvest and use BMPs Pollutant Control BMP Design IZI Included Worksheets/ Calculations (Required) Refer to Appendices B and E of the BMP Design Manual for structural pollutant control BMP design guidelines Use this checklist to ensure the required information has been included on the OMA Exhibit: The DMA Exhibit must identify: C>3l Underlying hydrologic soil group C>3l Approximate depth to groundwater □ Existing natural hydrologic features (watercourses, seeps, springs, wetlands) □ Critical coarse sediment yield areas to be protected (if present) C>3l Existing topography and impervious areas C>3l Existing and proposed site drainage network and connections to drainage offsite C>3l Proposed grading C>3l Proposed impervious features C>3l Proposed design features and surface treatments used to minimize imperviousness C>3l Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square footage or acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating) C>3l Structural BMPs (identify location and type of BMP) ATTACHMENT 1A LEGEND -------- ------- DMAX EXISTING MODIFIED WING-TYPE HEADWALL P~ 0-34 OF SDRSD PER PROJECT BOUNDARY OMA BOUNDARY DMA/0 LANDSCAPE AREAS OFFS/TE DISTURBED AREA STREETS/IMPERVIOUS FEATURES ROOFS BIOFIL TRA TION BASIN HYDROLOG IC SOIL TYPE CLEANOUT NOTE: GROUNDWATER NOT ENCOUNTERED EXISTING MODIFIED ffi1Pl£ TYPE 'G' CATCH BASIN PER D-08 OF SDRSD PER 409-4C EXJS17NG GROUND=270.2 r-4•-j-4·7 ,-& , . I ; -c-0-. ' ' ' 409-4(: RDIOVE/REPlACE EXISTING SUBDRAJN SITE DESIGN BMPS SD-2 CONSERVE NATURAL AREAS, SOILS, AND VEGETATION SD-3 MINIMIZE IMPERVIOUS AREA SD-4 MINIMIZE SOIL COMPACTION 111' PLANTING MIX SIN/HR MIN PERC RATE ARMORE:D BERM BOTTOM 27D.4 FG MIN. 3" N;GREGATE BELOW SIJBDRAJN EXISTlNG RIP-PAP NS ITE TYPICAL BIOFILTRATION BASIN DETAIL (PVT) (BASIN 2) NOTc.: El.EVAnONS SHOWN ARE ON NAVD BB. ELEVAnDNS ON DRAWING 409-4C AR£ ON NGVD 29 (2. 17' LOWER) NOT TO 5C.'l.£ DMA ID DMAlONSITE DMA2 *OFFSITE CO MME RI CAL AREA SOURCE CONTROL BMPS SC-1 PREVENTION OF ILLICIT DISCHARGES TO THE MS4 SC-2 STORM DRAIN STENCILING OR SIGNAGE DMASURFACE DMAAREA DMA TYPE BMP BMP ID STRUCUTRAL BMP ISQFTl AREA ISQFT \ ASPHALT, DRAINS TO CONCRETE, 36155 BIOFI LTRAT I ON BF-1 1500 BMP SLOPES ASPHALT, DRAINS TO CONCRETE, 217800 BIOFILTRAT ION BF-2 5598 BMP SLOPES ASPHALT, CONCRETE, 339768 ---- SLOPES *BASIN 215 NOT DESIGNED TO PROVIDE WATER QUALITY TREATMENT TO THE OFFSITE COMMERCIAL AREA VERTICAL CLEANOUT WITH LOCKABLE CAP AT THE END OF EACH SUBDRAIN. EXTEND ABOVE: FINISH GRADE. {TYPICAL) kiff~WiP T 8" PLANTING MIX SIN/HR MIN PERC RATE EXISTING BASIN OUTLET FOR BASIN T TOP OF BASIN .3,y'lj; , a,ylv,'.! 268. 6 FC -I I l=a,4-3 . '-=l It= >-'t:;~~~~ . ';cl I '77 '-1 ' UBDRAIN TO BE CONNECTED TO EXISTING OUTFLOW PIPE WITH ORIFICE PER HMP REPORI ''I 12" AGGREGATE STORAGE LAYER: 9" CLASS 2 PERMEABLE PER _~. CAL TRANS SPEC 68-1. 025 WITH 3" PEA GRAVEL FILTER COURSE LAYER JO MIL PVC UNER AT THE TOP. CLASS 3 PERMEABLE & XISTING/8" HDPE OUTFLOW PEA GRAVEL SHALL BE WASHED ANO (IMPERMEABLE). 261.8 FL FREE OF FINES. MIN. 3" AGGREGATE BELO'1 SUBDRAIN PER DWG 474-7A UPDTAED TO NGVD 88 BOTTOM TYPICAL BIOFl~TRATION BASIN DETAIL (PVT) (BASIN 1) NOT TO SCALE PREPARED BY: DMAMAP HU NSAKER LA COSTA TOWN & ASSOCIATES SAM DIEGO, I NC SQ UARE PARCEL 3 Pl»INING 'flrfl Waples Street ENGINEERING San Diego, Ca 92121 SURVEYING PH(858)558-4SOO· FX(858)558-1414 CITY OF CARLSBAD, CALIFORNIA SHEET 1 OF 1 -C I "' "' .,., .,., c; $ ATTACHMENT 1C Harvest and Use Feasibility Checklist Attachment 1C: Form 1-7 1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the wet season? D Toilet and urinal flushing ~ Landscape irrigation D Other: 2. If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours. Guidance for planning level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section B.3.2. E1WU=2.7[(0.Sx66957 /0.9)+0]0.015=1506 cubic feet 3. Calculate the DCV using worksheet B-2.1 . Total DCV = 6902 cubic feet (total onsite DCV) 0.25 DCV = 1726 cubic feet 3a. Is the 36 hour demand greater than or equal to the DCV? D Yes / ~ No c::> -0- Harvest and use appears to be feasible. Conduct more detailed evaluation and sizing calculations to confirm that DCV can be used at an adequate rate to meet drawdown criteria. 1820 3b. Is the 36 hour demand greater than 0.25DCV but less than the full DCV? D Yes / ~ No c::> ,(J. Harvest and use may be feasible. Conduct more detailed evaluation and sizing calculations to determine feasibility. Harvest and use may only be able to be used for a portion of the site, or (optionally) the storage may need to be upsized to meet long term capture targets while draining in longer than 36 hours. Is harvest and use feasible based on further evaluation? D Yes, refer to Appendix E to select and size harvest and use BMPs. ~ No, select alternate BMPs. 3c. Is the 36 hour demand less than 0.25DCV? ~ Yes .0. Harvest and use is considered to be infeasible. ATTACHMENT 1D ' Attachment 1d Categorization of Infiltration Feasibility Form 1-8 Condition Part t -Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes No D l:8l Soil type onsite is type C & D per geotechnical report prepared by Southern California Soils & Testing, Inc. on February 28d1, 2017. Additional evidence provided by the National Resources Conservation Service's Web Soil Survey, can be found in Attachment 5. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: D D Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Template Date: March 16, 2016 LUEG:SW PDP SWQMP -Attachments Preparation Date: July 14, 2016 ATTACHMENT 1E Imp. RF Pervious RF %Imp BASIN 0.90 0.10 0 INDUSTRIAL 0.90 0.10 87 MULTIUSE/COMMERCIAL 0.90 0.10 77 PARK 0.90 0.10 10 RESIDENTIAL/PATIOS 0.90 0.10 100 ROAD/DRIVEWAY 0.90 0.10 100 SCHOOL 0.90 0.10 80 SLOPES 0.90 0.10 0 7/13/2018 ATTACHMENT lE LA COSTA TOWN SQUARE PARCEL 3 BIOFILTRATION BMP OMA CALCULATIONS DMA2ONSITE Fraction of Pervious Summation RF BASIN2 Total Imp Area Area xA (sqft) (sqft) (sqft) 0.0 0 0 0 0 0.0 0 0 0 0 0.0 0 0 0 0 0.0 0 0 0 70239 0.5 70239 0 63215 68793 0.5 68793 0 61914 0 0.0 0 0 0 119562 0.1 0 119562 11956 258594 1 139032 119562 137085 5.94 0.00 Weighted C = 0.53 Pervious Summation RF DMA1BASIN 1 Fraction of Total Imp Area Area xA (sqft) (sqft) (sqft) 0 0.0 0 0 0 0 0.0 0 0 0 0 0.0 0 0 0 0 0.0 0 0 0 0 0.0 0 0 0 9000 0.7 9000 0 8100 0 0.0 0 0 0 29800 0.3 0 29800 2980 38800 1.0 9000 29800 11080 Weighted C= 0.29 R:\1204\&Hyd\CALCS\1204-Biofiltration Basins Slzing-Rl.xlsx 1 2 3 4 5 6 1 2 3 4 5 6 ATTACHMENT lE LA COSTA TOWN SQUARE -PARCEL 3 DCV CALCULATION OMA 2 combined: Design Capture Volume Worksheet B-2.1 B.1-1 d= 0.58 Area tributary to BMP (s) A= 5.94 Area weighted runoff factor (estimate using C= 0.53 Appendix B.1.1 and B.2.1) Street trees volume reduction TCV= 0.00 Rain barrels volume reduction RCV= 0.00 Calculate DCV= {3630 x C x d x A) -TCV -RCV DCV= 6,626 OMA 1 BASIN 1: Design Capture Volume Worksheet B-2.1 85th percentile 24-hr storm depth from Figure d= 0.58 B.1-1 Area tributary to BMP (s) A= 0.89 Area weighted runoff factor (estimate using C= 0.29 Appendix B.1.1 and B.2.1) Street trees volume reduction TCV= 0.00 Rain barrels volume reduction RCV= 0.00 Calculate DCV= (3630 x C x d x A) -TCV -RCV DCV= 536 inches acres unitless cubic-feet cubic-feet cubic-feet inches acres unitless cubic-feet cubic-feet cubic-feet 7/13/2018 R:\1204\&Hyd\CALCS\1204-Biofiltration Basins Sizing-Rl.xlsx 1 ATTACHMENT lE LA COSTA TOWN SQUARE -PARCEL 3 BIOFILTRATION BMP SIZING CALCULATION OMA 1 BASIN 1: Simple Sizing Method for Bloflltratlon BMPs Remaining DCV after implementing retention BMP's Partial Retention 2 Infiltration rate from Worksheet D.5-1 if partial infiltration is feasible 3 Allowable drawdown time for aggregate storage below the underdrain 4 Depth of runoff that can be infiltrated (Line 2 x Line 3) 5 Aggregate pore space 6 Required depth of gravel below the underdrain (Line 4/ Line 5) 7 Assumed surface area of the biofiltration BMP 8 Media retained pore storage 9 Volume retained by BMP (Line 4+(Line 12 x Line 8)/12) x Line 7 10 DCV that requires biofiltration (Line 1 -Line 9) BMP Parameters 11 Surface Ponding [6 inch minimum, 12 inch maximum] 12 Media Thickness [18 inches minimum], also add mulch layer thickness to this line for sizing calculations 13 Aggregate Storage above underdrain invert (12 inches typical) -use O inches for sizing if the agreagate is not over the entire bottom surface area 14 Freely drained pore storage 15 Media filtration rate to be used for sizing (5 in/hr. with no outlet control; if the filtration rate is controlled by the outlet use the outlet controlled rate) Baseline calculations 16 Allowable Routing Time for sizing 17 Depth filtered during storm (Line 15 x Line 16) 18 Depth of Detention Storage (Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)) 19 Total Depth Treated (Line 17 + Line 18) Option 1 -Biofllter 1.5 times the DCV 20 Required biofiltered volume (1.5 x Line 10) 21 Required Footprint (Line 20/ Line 19) x 12 Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) Volume (0.75 x Line 10) 23 Required Footprint (Line 22/ Line 18) x 12 Footprint of the BMP 24 Area draining to the BMP 25 Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) 26 BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum footprint sizing factor from Worksheet B.5-2, Line 11) 27 Minimum BMP Footprint (Line 24 x Line 25 x Line 26) 28 Footprint of the BMP = Maximum(Minimum(Line 21, Line 23), Line 27) Check for Volume Reduction [Not applicable for No Infiltration Condition] 29 Calculate the fraction of DCV retained in the BMP [Line 9/Line 1] 30 Minimum required fraction of DCV retained for partial infiltration condition 31 Is the fraction of DCV retained;:: 0.375? If the answer is no increase the footprint sizing factor in Line 26 until the answer is yes for this criterion. • BMP footprint based on BMP sizing factor 0.013 to meet hydromod requirements Worksheet B.5-1 536 cubic-feet 0.00 in/hr. 36.00 hours 0.00 inches 0.40 in/in 0.00 inches 1,500.00 sq-ft 0.10 in/in 225.00 cubic-feet 310.54 cubic-feet 6.00 inches 18.00 inches 12.00 inches 0.20 in/in 5.00 in/hr. 6.00 hours 30.00 inches 14.40 inches 44.40 inches 465.80 cubic-feet 126 sq-ft 233 cubic-feet 194 sq-ft 38,800.48 sq-ft 0.29 unitless 0.03 unitless 332 sq-ft 332 sq-ft N/A unitless N/A unitless □Yes □No 18:!N/A 2. The DCV fraction of 0.375 is based on a 40% average annual percent capture and a 36-hour drawdown time. 3. The increase in footprint for volume reduction can be optimized using the approach presented in Appendix B.5.2. The optimized footprint cannot be smaller than the alternative minimum footprint sizing factor from Worsheet B.5-2. 4. If the proposed biofiltration BMP footprint is smaller than the alternative minimum footprint sizing factor from Worksheet B.5-2, but satifies Option 1 or Option 2 sizing, it is considered a compact biofiltration BMP and may be allowed at the discretion of the County, if it meets the requirements in Appendix F. 1/14/2019 R:\1204\&Hyd\CALCS\1204-Biofiltration Basins Sizing-Rl .. ~ ' ,-•- ATTACHMENT lE LA COSTA TOWN SQUARE -PARCEL 3 BIOFILTRATION BMP SIZING CALCULATION 1 Remaining DCV after implementing retention BMP's 6,626 cubic-feet Partial Retention 2 Infiltration rate from Worksheet D.5-1 if partial infiltration is feasible 0.00 in/hr. 3 Allowable drawdown time for aggregate storage below the underdrain 36.00 hours 4 Depth of runoff that can be infiltrated (Line 2 x Line 3) 0.00 inches 5 Aggregate pore space 0.40 in/in 6 Required depth of gravel below the underdrain (Line 4/ Line 5) 0.00 inches 7 Assumed surface area of the biofiltration BM P 5,598.0 sq-ft 8 Media retained pore storage 0.10 in/in 9 Volume retained by BMP (Line 4+(Line 12 x Line 8)/12) x Line 7 560 cubic-feet 10 DCV that requires biofiltration (Line 1 -Line 9) 6,066 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 inch maximum] 10.00 inches 12 Media Thickness [18 inches minimum], also add mulch layer thickness to this line for sizing 12.00 inches calculations 13 Aggregate Storage above underdrain invert (12 inches typical) -use 0 inches for sizing if the 9.60 inches agreagate is not over the entire bottom surface area 14 Freely drained pore storage 0.20 in/in 15 Media filtration rate to be used for sizing (5 in/hr. with no outlet control; if the filtration rate 5.00 in/hr. is controlled by the outlet use the outlet controlled rate) Baseline Calculations 16 Allowable Routing Time for sizing 6.00 hours 17 Depth filtered during storm (Line 15 x Line 16) 30.00 inches 18 Depth of Detention Storage (Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)) 16.24 inches 19 Total Depth Treated (Line 17 + Line 18) 46.24 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltered volume (1.5 x Line 10) 9,099 cubic-feet 21 Required Footprint (Line 20/ Line 19) x 12 2,361 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) Volume (0.75 x Line 10) 4,549 cubic-feet 23 Required Footprint (Line 22/ Line 18) x 12 3,362 sq-ft Footprint of the BMP 24 Area draining to the BMP 258,594 sq-ft 25 Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) 0.53 unitless 26 BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum footprint sizing factor 0.03 unitless from Worksheet B.5-2, Line 11) 27 Minimum BMP Footprint (Line 24 x Line 25 x Line 26) 4,113 sq-ft 28 Footprint of the BMP = Maximum(Minimum(Line 21, Line 23), Line 27) 4,113 sq-ft Check for Volume Reduction [Not applicable for No Infiltration Condition) 29 Calculate the fraction of DCV retained in the BMP [Line 9/Line 1] N/A unitless 30 Minimum required fraction of DCV retained for partial infiltration condition N/A unitless 31 Is the fraction of DCV retained ~ 0.375? If the answer is no increase the footprint sizing factor □Yes □No ~N/A in Line 26 until the answer is yes for this criterion. * BMP footprint based on BMP sizing factor 0.013 to meet hydromod requirements 1/14/2019 R:\1204\&Hyd\CALCS\1204-Biofiltration Basins Sizing-Rl Attachment Sequence Attachment 2a Attachment 2b Attachment 2c Attachment 2d ATTACHMENT 2 BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES [This is the cover sheet for Attachment 2.) Indicate which Items are Included behind this cover sheet: Contents Checklist Hydromodification Management Exhibit ~ Included (Required) Management of Critical Coarse Sediment Yield Areas (WMM Exhibit is required, additional analyses are optional) See Section 6.2 of the BMP Design Manual. Geomorphic Assessment of Receiving Channels (Optional) See Section 6.3.4 of the BMP Design Manual. See Hydromodification Management Exhibit Checklist on the back of this Attachment cover sheet. ~ Exhibit showing project drainage boundaries marked on WMM Critical Coarse Sediment Yield Area Map (Required) Optional analyses for Critical Coarse Sediment Yield Area Determination ~ 6.2.1 Verification of Geomorphic Landscape Units Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite ~ Not performed D Included Flow Control Facility Design and ~ Included Structural BMP Drawdown Calculations (Required) See Chapter 6 and Appendix G of the BMP Design Manual ATTACHMENT 2A Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit: The Hydromodification Management Exhibit must identify: IZI Underlying hydrologic soil group IZI Approximate depth to groundwater □ Existing natural hydrologic features ( watercourses, seeps, springs, wetlands) □ Critical coarse sediment yield areas to be protected (if present) IZI Existing topography IZI Existing and proposed site drainage network and connections to drainage offsite IZI Proposed grading IZI Proposed impervious features IZI Proposed design features and surface treatments used to minimize imperviousness IZI Point(s) of Compliance (POC) for Hydromodification Management IZI Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) IZI Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) LEGEND -------- ------- x.ac © • PROJECT BOUNDARY DRAINAGE BOUNDARY AREA ACREAGE LANDSCAPE AREAS HYDROLOGIC SOIL POC + .331.'-x 333.5 V " " X 338.5 X 1 337.5 T 1 ---r-4 X ~~o.. - _,. \ X _.--, 1 --,-. 335 335 '< ,--__ -,-----, -, ~ \ '> ,;;iii-~~~ ASPH ,.).J~ ...... ' I X + PREPARED BY: HUNSAKER & ASSOCIATES SA M DIEGO. INC. aples Street PlANNINC 'll'11W "'-o, Ca 921Z1 ENQNEERING San ~~, 500· FX(858)SS8-1414 SURVEVING PH(858)558-4 POC POC 1 POC 2 263.5 X ( ' ~ 264. • ? 6 -~\ X -~ ~ ~\ "\ + MARY TABLE DRAINAGE SUM DESCRIPTION OF ORAi NAGE AREA ORAi NAGE AREA (ACRES) ONSITE AREA 3.2 10.3 EAST ONSITE AREA WEST+ OFFSITE COMMERICAL EXISTING HMP M~N SHEET 1 OF s Q u A RLSBAD, CALIFORNIA CITY OF CA 4 0 I ,,., ,,., ::i 0 ;,; \ LEGEND =---==-1P~R1CO~J'EIECTBOUNDARY DRAINA GE BOUNDARY -- x.ac © • AREA ACREAGE LANDSCAPE AREAS HYDROLOGIC SOIL POC \ ~ ~-~,..,. /, ;7 ' _,.....-'\ .,, -::::::- /~\ ~ ;_.. _\,P __.,._;:,-- -,~,i;-~"'1fr~ \ " r "t-{i~~ \·II fi•..,-l!liiq~~ l"!1 i'1' 't -r --~r,I @l '"' '--~, i I 'i:rc~ · : \ \ I \ '''¾.. -. ,ii;irll\J!~.>lll I.I', ;1 i.J . ~ / -· ,\ ':i -I :ti,,,_=~£:: \ : I ' -. -~, . -AO . ""' ,-,. . ~.89 .. ;;:_. ,,. · /4 , ·poOO~-"'-. . ~-/,.. '•,· ~ ' . ,, • C , , •, /4 ····~· . --...... ~ ~ \ \ . -// ' --.. ---• . ' ® --" I C:::t.t~ . . ,.,,,,,."" " ..., ' --;, °v;;' ,~ . / ,Y ,,--\ ;(:_\-; \ ----;1,e ,,,,_. I . . ±-~ • ,j/1 ",&st,=- / . --~ aj'. 20. '"""''""· ],.,,.,,~. <f-1 ,,\ \-1:::-. '/ ., '""'"'°'' P~, -IJ''°:. , I ') 1l ~11,:; \ / ~-,, ~-..... _,'·\'\' \ . ,. -.. u• : ~~4:r~t ~--aw \'ti\ " / , "'. / ::. , ' • ' , 15AO -.-.,~-◄:;;:~, , -1', · I // ,1·1..--,,..,.,.,, "~~~~'f ,~A'\\ ~:-i~Q, .,., ,",I ,, ' ' -/ / '('l's I\ -~ , •l, :6 i,,\jf':Y"'" '-,.___ • 1~ ~~ ~ A / , ' ' / ,,/ /4 ;,-,'ii, ~ n / fa=. / / -i~~ r ~-/ / < • --,,.,,.,,,,_ I ·-, / =,,, '1 ' .. / / • -~, J \ ' ~,_.,:.,: 0 ~~. • ;. ""·: \ -. -' --ef/1, '"''\\'ilt----:. I I<'. -/ ·-•=\ " , / ,, //, CP'. 11'' Q "lf"'11"'f\ -~V • .. .._,_,, · / , .. , •" -. , '"'"'"' .. ' ' , ' ' <'Y , ',, "' ~~::.::;l:: •j ·:· . i-f•~;~ ~-c.-'...f./. •• -~,--, .,, ,/ /, •• /' ·"•, .-;~ ;:,i,' §~~:. _,.,,, .. --~ \I ,,.,.,_ • • ' .. < / \ . .-v , -.. , ~ . . ...._ f>.._ .;.~, .. ....,, I s s -, \ DRAINAGE SUM DESCRIPTION OF DRAINAGE AREA DRAINAGE AREA (ACRES ) ONSITE AREA EAST POC'"l!__i----~ 3 -1 2 --t(o~N~S~l~T~E~A!R~EA~E cc W EST+ OFFS ITE MARY TABLE POC POC 2 10.3 CO M M ERICAL HMP MAP ----:=~-, EXISTING TOWN I p ~R'EPAR:~;8a1i\Es LA ciirtARCEL 3 ~; "'"" '"" SQUA CALIFORN IA SHEET 2 OF CITY OF CARLSBAD, 9707 Waples Street . Ca 92121 San Q;ego, FX(BS8)558-1414 PH(858)SS84S00· 4 LEGEND -------- ------- DMAX © • EXISTTNG MOOIF/£D WfNG-ITPE HEADWALL P. D-J-4 OF SDRSD P£R ,f.()9--'f.C PROJECT BOUNDARY DMA BOUNDARY DMAID LANDSCAPE AREAS STREETS/IMPERVIOUS FEATURES ROOFS BIOFIL TRA TION BASIN HYDROLOGIC SOIL TYPE p_OJNT OF COMPLIANCE CLEANOUT NOTE: GROUNDWATER NOT ENCOUNTERED REMOVE/REPLACE EX1STING SUBDR4JN SITE DESIGN BMPS SD-2 CONSERVE NATURAL AREAS, SOILS, ANO VEGETATION SD-3 MINIMIZE IMPERVIOUS AREA SD-4 MINIMIZE SOIL COMPACTION SD-5 IMPERVIOUS AREA DISPERSION SD-7 LANDSCAPING WITH NATIVE OR DROUGHT TOLERANT SPECIES .. \ ~ _,,-c~~~~ •'' 3.2 ~ X ,..,-- BOTTOM UIN. 3" AGGREGATE BELOW SUBDRAIN NSITE IL AGGRE"~TE ST'CIRJtGE. U.YER: !7 Cl.ASS 2 PERIIE:ABLE PER 00.77WiS SPEC 68-1.025 wm-1 :!" ~ ®YEI. FILTER COORS£ ~l'E'R AT THf: rop_ ctASS J PERJJ[J,8.£ ct Pf:ot GRAV.El.. ~ BE WASHED AND FfaOFF/f/E£ _i-7- I DMAID DMA 1 ONSITE DMA2 *OFFSITE COMMERICAL TYPICAL BIOFILTRATION BASIN DETAIL (PVT) (BASIN 2) AREA NOT TO SC,OJ.£ [Q] DMA SURFACE ASPHALT, CONCRETE, SLOPES ASPHALT, CONCRETE, SLOPES ASPHALT, CONCRETE, SLOPES SOURCE CONTROL BMPS SC-1 PREVENTION OF ILLICIT DISCHARGES TO THE MS4 SC-2 STORM DRAIN STENCILING OR SIGNAGE SC-6 ONSITE STORM DRAIN INLETS SC-6 NEED FOR FUTURE INDOOR & STRUCTURAL PEST CONTROL SC-6 LANDSCAPE/OUTDOOR PESTICIDE USE DMAAREA STRUCUTRAL BMP OMA TYPE BMP BMP ID (SQFT) AREA (SQFT) 36155 DRAINS TO BIOFILTRATI ON BF-1 1500 BMP - VERTfCAL CLEANOUT WllH LOCKABLE CAP AT THE END OF EACH SUBDRAIN. £XID/D ABOVE" FlNISH GRAD£. (TYPICAL) tlf]~7l/if, J,y_.l'V ·1, (-¼y 12" AGGREGATE STORAGE LA'r'm: 9" Cl.ASS 2 PERAlfABl£ PER CALTRANS SPEC 68-1.025 WITT/ .Y PEil GIMiin FILTtR COURSE lA'fER AT 11{[ TOP. Cl.ASS J PERMEABLE ,t PEA GR4VEZ. SHALL B£ WAS"HED AND FREE OF F1N£S. 1K PlANTING MIX SIN/HR MIN PERC RA71': EXISTING BASIN 0/Jn.ET FOR BASIN t MIN. Y AGGREGATE BELOW SUBDRAIN 261.8 FL ,-,---TOP OF BASIN UBDRAIN TO 8£ CDNNECTFD TO EXISnNG oum.ow PU'£ WITH Of?JFJCE PER HUP REPORT PER owe; ~u-7A UPOTAED TD NGVD 88 BOTTOM TYPICAL BIOFILTRATION BASIN DETAIL (PVT) (BASIN 1) NOT TO SCALE PREPARED BY: PROPOSED HMP MAP LA COSTA TOWN SQUARE PARCEL 3 DRAINS TO 217800 BIOF ILTRATION BF -2 5598 BMP HU NS AI<ER & ASSOCIATES 339768 ---SAN DIEGO. INC NOT£: El.EVAT10NS SHOWN ME ON NAW'.l 88. a£o/A710NS ON DRAWING 409--IC ARE ON NGVD 29 (2. f 7 LOWffi) rBASIN 2 15 NOT DESIGNED TO PROVIDE WATER QUALITY TREATMENT TO THE OFFSITE COMMERCIAL AREA PIANNINC '1707 Waples Street ENQNB'RING San [);ego, Ca 92121 SURVEYING PH(858)558-4500· FX(8Sll)SS8-1414 CITY OF CARLSBAD, CALIFORNIA SHEET 3 OF D I 4 "' "' "l "l c:i ~ LEGEND -------- ------- DMAX © • 0 STRUCUTRAL BMP's DMA1 ONSITE DMA2 *O FFS IT E COMMERICAL AREA PROJECT BOUNDARY OMA BOUNDARY DMAID LANDSCAPE AREAS STREETS/IMPERVIOUS FEATURES ROOFS BIOFIL TRA TION BASIN HYDROLOGIC SOIL TYPE POINT OF COMPLIANCE CLEANOUT N~~ \ OUN '.4 TER NOT ENCOUNTERED *BASIN 21S NOT DES IGNED TO PROVIDE WATER QUALITY TREATMENT TO THE OFFS I TE COMMERCIAL AREA \ \ I SITE DESIGN BMPS SD-2 CONSERVE NATURAL AREAS, SOILS, AND VEGETATION SD-3 MINIMIZE IMPER VIOUS AREA SD-4 MINIMIZE SOIL COMPACTION SD-5 IMPERVIOUS AREA DISPERSION SD-7 LANDSCAPING WITH NATIVE OR DROUGHT TOL ERA NT SPECIES ~ ---- [Q] SO URCE CONTR OL BMPS SC-1 PREVENTION OF ILLICIT DISCHARGES TO THE MS4 SC-2 STORM DRAIN STENCILING OR SIGNA GE SC-6 ONSITE STORM DRAIN INLETS SC-6 NEED FOR FUTURE INDOOR & STRUCTURAL PEST CONTROL SC-6 LANDSCAPE/OUTDOOR PESTICIDE USE SC-6 PLAZAS, SIDEWALKS, AND PARKING LOTS . 6 1.1;, -_.,7 ~· PREPARED BY: -PLANNING ENQNEERING SURVEYING HUNSAI<ER & ,1\SSOCIA TES SAN DIEGO, INC 'fl(fl Waples Street San Diego, Ca 92121 PH(B58)558-4500 · FX(B58)558-1414 - I -+ PROPOSED HMP MAP LA COSTA TOWN SQUARE PARCEL 3 CITY OF CARLSBAD, CALIFORNIA SHEET 4 OF 0 I 4 :g "l "l c:i " 3: "' ~ Hydrologic Soil Group-San Diego County Area, California 33" 4'53"N I· I I 2 i Ii! i ~ 33"4'45"N m· ~ 4781~ 4781~ N A 47811!J 47BZ10 478.l40 478210 478D) 47833J \!) ~ 47811!J 47BZ10 478240 478Z10 478D) 478J3J Map Scale: 1:1,630 f i:r1rm:i on A lin:l!l:.ipe (11" X 8.5") sheet ---====------=======Me!Bs o ~ ~ oo m ---===------======feet 0 5:l 100 200 :n, Map~= wm Mercator canerroordraes: WGS84 Edge tics: lJlM 2me 11N WGS84 USDA Natural Resources Web Soil Survey National Cooperative Soil Survey aiii Conservation Service 478El 478300 478:B) 47843) 478450 478El 47843) 478450 47841D 47841D 3: ~ ~ ~ 3: ~ ~ ~ I i I I I 2 i Ii! i ~ i 5/30/2017 Page 1 of4 33" 4'53"N J304'45"N ~ Hydrologic Soil Group-San Diego County Area, Galifomia MAP LEGEND MAP INFORMATION Area of Interest (AOI) D Area of Interest (AOI) Soils Soil Rating Polygons D A D AID D B D BID D C D CID D D D Not rated or not available Soil Rating lines -A -AID -B -BID -C -CID -D -,, Not rated or not available Soil Rating Points ■ A ■ AID ■ B ■ B/D Natural Resources Conservation Service ■ C ■ CID ■ D a Not rated or not available Water Features ~ Streams and Canals Transportation ++t Rails ,,.; lnlerstate Highways ,,.; US Routes ~ Major Roads local Roads Background ■ Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 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. 5/30/2017 Page 2of 4 Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Hydrologlc Soll Group-Summary by Map Unit -San Diego County Area, California (CA638) Map unit symbol Map unit name Rating AtE Altamont clay, 15 to 30 C percent slopes, warm MAAT, MLRA 20 HrD2 Huerhuero loam, 9 to 15 D percent slopes, eroded SnG San Miguel-Exchequer D rocky silt loams, 9 to 70 percent slopes Totals for Area of Interest USDA Natural Resources '"' Conservation Service Web Soil Survey National Cooperative Soil Survey Acres lnAOI 3.3 3.7 0.1 7.1 Percent of AOI 46.3% 52.3% 1.4% 100.0% 5/30/2017 Page 3 of4 Hydrologic Soil Group-San Diego County Area, California Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (ND, BID, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (ND, BID, or CID), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 5/30/2017 Page 4 of 4 ATTACHMENT 2B WMMMAP PROJECT BOUNDARY CRITICAL COURSE SEDIMENT YIELD AREAS Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas Map Unit Kvsp Kwmt Qv Tba Tda Tv Tvsr Kgdfg Ta Tes Td Qls Tm Tf Tfr To Qpe Mexico Kuo Teo Tmo Qmo QTso af Map Name Oceanside 30' x 60' Oceanside 30' x 60' Jennings; CA San Diego 30' x 60' Oceanside 30' x 60' Oceanside 30' x 60' Oceanside 30' x 60' Oceanside 30' x 60' San Diego 30' x 60' Oceanside 30' x 60' San Diego & Oceanside 30' X 60' San Diego, Oceanside & El Cajon 30' x 60' Oceanside 30' x 60' San Diego, Oceanside & El Cajon 30' x 60' El Cajon 30' x 60' San Diego & El Cajon 30' X 60' San Diego & Oceanside 30' X 60' San Diego 30' x 60' San Diego 30' x 60' San Diego & Oceanside 30' X 60' Oceanside 30' x 60' San Diego 30' x 60' San Diego 30' x 60' San Diego & Oceanside 30' X 60' Anticipated Grain size of Bedrock or I mpermcablc/ Geology Weathered Sedimentary Permeable Grouping Material Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impenneable FB Fine Bedrock Impermeable FB Fine Sedimentary Impermeable PSI Fine Sediment FSI Fine Sedimentary Impermeable FSI me e 1mentary Fine Sedimentary Impenneable PSI Fine Sedimentary Impermeable FSI Fine Sedimentary Impenneable FSI Fine Sedimentary Impermeable FSI Fine Sedimentary Impermeable FSI Fine Sedimentary Penneable FSP NA NA Penneable Other NA (Offshore) NA Permeable Other NA (Offshore) Sedimentary Permeable Other NA (Offshore) Sedimentary Permeable Other NA (Offshore) Sedimentary Penneable Other NA (Offshore) Sedimentary Permeable Other Variable, dependent on Sedimentary Other source material H-10 February 2016 Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas Id SanGIS Legend SanGIS Grouping Land Cover Grouping 155 37400 Semi-Desert Chaparral Scrub/Shrub 156 37500 Montane Chaparral Scrub/Shrub 157 37510 Mixed Montane Chaparral Scrub/Shrub 158 37520 Montane Manz.anita Chaparral Scrub/Shrub 159 37530 Montane Ceanothus Chaparral Scrub/Shrub 160 37540 Montane Scrub Oak Chaparral Scrub/Shrub 161 37800 Upper Sonoran Ceanothus Scrub/Shrub Chaparral 162 37830 Ceanothus crassifolius Chaparral Scrub/Shrub 163 37900 Scrub Oak Chaparral Scrub/Shrub 164 37 A0O Interior Live Oak Chaparral Scrub/Shrub 165 37C30 Southern Maritime Chaparral Scrub/Shrub 166 37000 Coastal Sage-Chaparral Scrub Scrub/Shrub 167 37K00 Flat-topped Buckwheat Scrub/Shrub 168 39000 Upper Sonoran Subshrub Scrub Scrub and Chaparral Scrub/Shrub 169 Diegan Coastal Sage Scrub Scrub/Shrub 170 Granitic Northern Mixed Chaparral Scrub/Shrub 171 Southern Mixed Chaparral Scrub/Shrub 172 11000 Non-Native Vegetation Unknown 173 11000 Non-Native Vegetion Vegetation Unknown 174 11200 Disturbed Wetland Non-Native Vegetation, Unknown 175 11300 Disturbed Habitat Developed Areas, or Unknown 176 13000 Unvegetated Habitat Unvegetated Habitat Unknown 177 Disturbed Habitat Unknown H-16 February 2016 Appendix H: Guidance for Investigation Potential Critical Coarse Sediment Yield Areas Table H.1-3: Potential Critical Coarse Sediment Yield Areas GLU Geology Land Cover Slope (%) CB-Agricultural/ Grass-3 Coarse Bedrock Agricultural/ Grass 20%-40% CB-Agricultural/ Grass-4 Coarse Bedrock Agricultural/ Grass >40% CB-Forest-2 Coarse Bedrock Forest 10-20% CB-Forest-3 Coarse Bedrock Forest 20%-40% CB-Forest-4 Coarse Bedrock Forest >40% CB-Scrub/Shrub-4 Coarse Bedrock Scrub/Shrub >40% CB-Un.known-4 Coarse Bedrock Unknown >40% CSI-Agricultural/Grass-2 Coarse Sedimentary Impermeable Agricultural/Grass 10-20% CSI-Agricultural/Grass-3 Coarse Sedimentary Impermeable Agricultural/ G rass 20%-40% CSI-Agricultural/ Grass-4 Coarse Sedimentary Impermeable Agricultural/ Grass >40% CSP-Agricultural/Grass-4 Coarse Sedimentary Permeable Agricultural/ G rass >40% CSP-Forest-3 Coarse Sedimentary Permeable Forest 20%-40% CSP-Forest-4 Coarse Sedimentary Permeable Forest >40% CSP-Scrub/Shrub-4 Coarse Sedimentary Permeable Scrub/Shrub >40% GLU ANALYSIS FOR MITIGATION OF CCSY As The project level GLU analysis was performed following the Carlsbad BMP Manual Section 6.2 and Appendix H. Based on the Geotechenical Study provided by SCST Inc., the site has predominately Td (Del Mar Formations) classified as "Fine Sedimentary Impermeable (FSI)", JMV (Metamorphic Rock) classified as "Coarse Bedrock (CB)", and additional areas covered by fill are classified as "Other". The site is currently graded pad with disturbed habitat so the land cover is classified as "Unknown". Existing slopes on site are less than 10%. and onsite GLU's are identified below: FSI-unknown-1 CB-unknown-I Other-unknown-I None of the GLU's identified on site are listed in Table H.1-3 of the Carlsbad BMP Manual Appendix H and therefore, no measures for protection of Critical Coarse Sediment Yield Areas on site are necessary H-17 February 2016 I I I I I I I I I I I I I I I I I I SCST, Inc. --------------A GEOTECHNICAL MAP La Costa Town Square Multi-Family Housing Carlsbad, California 120' 0 TP-18 II • • • • Jmvm SCST LEGEND: Approximate Location of Test Pit Approximate Geologic Contact Approximate Buried Geologic Contact Delmar Formation, Circled Where Buried By Compacted Fill Decomposed Metamorphic Rock, Circled Where Buried By Compacted Fill Decomposed Metamorphic Rock Metamorphic Rock, Moderately Weathered Date: March, 2017 Figure: By: MAW Job No.: 160518N 2 PREPARED BY: 0 40 80 120 HUNSAKER 2-I I & ASSOCIATES SCALE 1" =40' SAN DIEGO, INC. PIANNING 'J7W Waples Street ENGINEERING San Diego, Ca 92121 SURVEYING PH(858)558·4500 • FX(858)558-1414 EXISTING SITE LA COSTA TOWN SQUARE PARCEL3 Carlsbad, California ' \ 26( X ' @ SHEET 1 OF 1 R:\ 1204\$Dot\ 1204$APD-EX.dwg[JSep-10-2014: 15:34 ., °' g I C, "' "" C, 0 ,,; -• ---• -• -.. - ---.. --- - -.. - - -.. .. .. .. -.. - ATTACHMENT 2D • - ----... -.. ---.. -------• -.. -• ... .. .. .. Hydromodification Management Plan -• -- - .. -.. ------- • • --- ---• --- INTRODUCTION This report summarizes the approach used to model the proposed La Costa Town Site Parcel 3 project site in the City of Carlsbad using the Environmental Protection Agency (EPA) Storm Water Management Model 5.1 (SWMM). SWMM models were prepared for the pre and post developed conditions at the site in order to determine if the proposed biofiltration facilities have sufficient footprint to meet the current Hydromodification Manage- ment Plan (HMP) requirements from the Regional Water Quality Control Board (RWQCB). SWMM MODEL DEVELOPMENT Two (2) SWMM models were prepared for this study, one for Point of Compliance 2 (POC2) in pre-developed conditions onsite and one proposed condition. POC2 was sized using the sizing calculator. For all SWMM models, flow duration curves were prepared to demonstrate that the proposed biofiltration basin design will be sufficient to meet the current HMP requirements. The inputs required to develop SWMM models include rainfall, watershed characteristics, and BMP configurations. The Oceanside Rain Gage from the Project Clean Water website was used for this study, since it is the most representative of the project site precipitation . Evaporation for the site was modeled using average monthly values from the San Diego County hourly dataset. The site was modeled with hydrologic soil group A soils as determined from both the San Diego County Hydrology Manual soil map and the USGS Survey web-based Soil Survey Map. Other SWMM inputs for the subareas are discussed in the attachment to this document where the selection of the parameters is explained in detail. BIOFILTRATION MODELING Developed storm water runoff is routed through One (1) Biofiltration Basin. The basin was modeled using the bioretention LID module within SWMM. The bioretention module can model the underground gravel storage layer, underdrain with an orifice plate, amended soil layer, and a surface storage pond up to the elevation of the invert of the bottom orifice. Once runoff has been routed through the respective basin outlet structures, it is conveyed via a storm drain pipe to the POC. Basin Discussion: Flow control in the basin is achieved using multiple orifices on a concrete riser box. The size, number and location of the orifices are presented in the Basin Table below. Basin 2 is a detention basin that includes a biofiltration area that is designed to provide water quality treatment for the discharge associated with LCTS (Parcel 3). The Biofiltration area provides 6" of ponding, 18" of engineered soil, and 12" of gravel per requirements set forth in the BMP manual. Flows in the biofiltration area will pond above the required 6" and will spillover into the detention area of basin 2. The existing outlet structure associated with detention area of basin 2 has a bottom orifice height of 0.4 feet which will not be modified as the 6" of required ponding is achieved by the biofiltration area of basin 2. Each basin also contains an emergency overflow riser that is only utilized in storm events equal to or larger than the 100 year storm. Sizing and further peak flow discussion is in the "Drainage Report for La Costa Town Square Parcel 3". Also, refer to the SWMP and drainage report prepared by O'day for detention basin and hydromodification calculations. ---.. -------- ------- .. --- ----------- -• • • • • .. ---.. ---- - • --• ---• -------.. -- Basin 1 Basin 2 (POC 1) (POC 2) Weir Height* (in) 10 6 Weir Length (in) 6 10 Amended Soil Depth 18 18 Class 2 Perm. Depth (in) 12 12 TOP ORIFICE No. of Orifices - - Diameter (in) -- Invert Height (ft)* - - MIDDLE ORIFICE No. of Orifices - - Diameter (in) - - Invert Height (ft)* - - BOTTOM ORIFICE No. of Orifices 0 1 Diameter (in) 0 10 Invert Height (ft)* 0.4 0 (O.S**) SUB DRAIN ORIFICE No. of Orifices l l Diameter (in) l 5 *from finish grade ** Within the BF-BMP per BMP manual NOTE: Sizing Calculation Results Included FLOW DURATION CURVE COMPARISON The Flow Duration Curves (FDC) for the site were compared at POC 1 by exporting the hourly runoff time series results from SWMM to a spreadsheet. The FDC was compared between 10% of the existing condition Qi (based on accepting an assumption of high susceptibility for downstream channel erosion as required if no soils tests are completed) up to the existing condition Q10. The Qi and Q10 were determined using a partial duration statistical analysis of the runoff time series in an Excel spreadsheet. The SWMM Model is a statistical analysis based on the Weibull Plotting Position Method . The range between 10% of Qi and Cho was divided into 100 equal time intervals; the number of hours that each flow rate was exceeded was counted from the hourly series. Additionally, the intermediate peaks with a return period "i" were obtained (Q with i=3 to 9). For the purpose of the plot, the values were presented as percentage of time exceeded for each flow rate. The FDC comparison at POC 1 is illustrated in Figure 1. As can be seen in Figures 1 & 2, the FDC and Peak Flow Frequency curve for the proposed condition are within 110% of the curve for the existing condition. The additional runoff volume generated from developing the site will be released to the downstream storm drain at a flow rate below the 10% Ch lower threshold. Additionally, the project will not increase peak flow rates between the Ch and the Oio, as shown in the graphic and also in the attached table. SUMMARY & CONCLUSION A summary of existing and proposed areas draining to each point of compliance (POC) are shown in the table below. The model includes the onsite project areas and offsite drainage areas, in this case the town center just adjacent to the property. BF-1 experiences a reduction in drainage area in the developed condition when compared to the existing condition. One storage basins are proposed to mitigate increased flow frequencies as a result of development. Area Summary Existing (AC) Proposed (AC) POCl 3.2 .83 POC2 10.3 12.7 TOTAL 13.5 13.5 ------------- ------------------------ - -.. -• • • • -• ---• -• -• .. • ---• -----• ... - This study has demonstrated that the proposed biofiltration footprint at the La Costa Town Site Parcel 3 site is sufficient to meet the current HMP criteria if the biofiltration cross-section areas and volumes recommended within this attachment are incorporated within the proposed project site . KEY ASSUMPTIONS 1. D Soils are representative of the existing conditions for a majority of the site . ATTACHMENTS 1. Flow Duration Curve Analysis 2. Elevation vs. Area Curves vs. Discharge Curves to be used in SWMM 3. Biofiltration Details 4. SWMM Input Data (Existing and Proposed Models) 5. SWMM Screens and Explanation of Significant Variables Flow duration curve shall not exceed the existing conditions by more than 10% neither in peak flow nor duration. The figure on the following page illustrates that the flow duration curve in post-development conditions after the proposed BMPs is below the existing flow duration curve. The flow duration curve table following the curve shows that if the interval 0.l0Q 2 - Q 10 is divided in 100 sub-intervals, then a) the post development divided by pre-development durations are never larger than 110% (the permit allows up to 110%); and b) there are no more than 10 intervals in the range 101%-110% which would imply an excess over 10% of the length of the curve (the permit allows less than 10% of excesses measured as 101-110%). Consequently, the design passes the hydromodification test. It is important to note that the flow duration curve can be expressed in the "x" axis as percentage of time, hours per year, total number of hours, or any other similar time variable. As those variables only differ by a multiplying constant, their plot in logarithmic scale is going to look exactly the same and compliance can be observed regardless of the variable selected. The selection of a logarithmic scale in lieu of the normal scale is preferred, as differences between the pre-development and post-development curves can be seen more clearly in the entire range of analysis. Both graphics are presented for reference. In terms of the "y" axis, the peak flow value is the variable of choice. As an additional analysis performed by H&A, not only the range of analysis is clearly depicted (10% of Q 2 to Q 10) but also all intermediate flows are shown (30% of Q 2 , 50% of Q 2 , Q 2 , Q 3 , Q 4, Q 5 , Q 6 , Q 7 , Q 8 and Q 9 ) in order to demonstrate compliance at any range Q x - Q x+l . It must be pointed out that one of the limitations of both the SWMM and SDHM models is that the intermediate analysis is not performed (to obtain Q i from i = 2 to 10}. H&A performed the analysis using the Cunnane Plotting position Method (the preferred method in the HMP permit) from the "n" largest independent peak flows obtained from the continuous time series. The largest "n" peak flows are attached in this appendix, as well as the values of Q with a return period "i", from i=2 to 10. The Qi values are also added into the flow-duration plot. ---.. ---------.. ---.. -------.. ---------.. -.. FIGURE 1 10.000 9.000 8.000 7.000 ~ 6.000 i 0 u:: 5.000 4.000 3.000 2.000 1.000 I 0.000 1.0E-06 Flow Duration Curve -POC 2 [Pre vs. Post {Mitigated)] I 1111 I D I I I I I -I II-I I '9g D--g °i ~ I q ~ -6-:t. ~ ~ -\ a! \ I ~ ~ t. ~ ' I I 1.0E-05 1.0E-04 % Time Exceeding ~ Pre-project Q ~ .... -6-Post-project (Mitigated) Q I I 1.0E-03 1.0E-02 FIGURE 2 Peak Flow Frequency Curves 10.000 9.000 I I I I I I --8.000 :, .... -:,... I-"' I-"' ~ , .... 7.000 "' 6.000 'C .E 3 5.000 0 i:i: .x IO cu 0. 4.000 3.000 I-"' I-"' ... l t:?' .... .... I-""" I ----.... -~ --I '-I .... n" aD'" ' --I i1~ ._,,,/ I-' I . ,... ,:r ---..--11 ,_ ~ ,....tr --I I I ----I ·~ I --0-Pre-project Qpeak I ,/'/ I ~ I ~ -6-Post-project Mitigated Qpeak -. '--. . I .. ----2.000 1.000 0.000 ffl I I I I I I I I I I 0 1 2 3 4 5 6 7 8 9 10 Return Period in Years POC2 LA COSTA TOWN SQUARE BASIN2-SWMM Low-flow Threshold: II 50% II 0.5xQ2 (Pre): 2.720 cfs Ql0(Pre): 9.403 cfs Ordinate#: 100 Incremental Q (Pre): 0.06683 cfs Total Hourly Data:11 497370 llhours The proposed BMP:._! __ P_AS_s_E_o _ _. Pre-project Pre-project Pre-project% Post-project Post-project% Interval Flow Percentage Pass/Fail (cfs) Hours Time Exceed"ing Hours r11ne Exceeding 0 2.720 175 3.52E-04 16 3.22E-05 9% Pass 1 2.786 162 3.26E-04 16 3.22E-05 10% Pass 2 2.853 159 3.20E-04 15 3.02E-05 9% Pass 3 2.920 151 3.04E-04 15 3.02E-05 10% Pass 4 2.987 142 2.86E-04 15 3.02E-05 11% Pass 5 3.054 126 2.53E-04 14 2.81E-05 11% Pass 6 3.120 116 2.33E-04 13 2.61E-05 11% Pass 7 3.187 113 2.27E-04 13 2.61E-05 12% Pass 8 3.254 109 2.19E-04 13 2.61E-05 12% Pass 9 3,321 108 2.17E-04 13 2.GlE-05 12% Pass 10 3.388 102 2.05E-04 13 2.61E-05 13% Pass 11 3.455 98 l.97E-04 13 2.61E-05 13% Pass 12 3.521 97 1.95E-04 13 2.GlE-05 13% Pass 13 3.588 89 1.79E-04 13 2.61E-05 15% Pass 14 3.655 86 l.73E-04 13 2.61E-05 15% Pass 15 3.722 82 1.65E-04 13 2.61E-05 16% Pass 16 3.789 72 l.45E-04 13 2.61E-05 18% Pass 17 3.856 66 1.33E-04 13 2.61E-05 20% Pass 18 3.922 64 1.29E-04 13 2.61E-05 20% Pass 19 3.989 60 1.21E-04 13 2.61E-05 22% Pass 20 4.056 60 l .21E-04 11 2.21E-05 18% Pass 21 4.123 59 l .19E-04 11 2.21E-05 19% Pass 22 4.190 58 l .17E-04 11 2.21E-05 19% Pass 23 4.257 57 l.15E-04 11 2.21E-05 19% Pass 24 4.323 55 l.llE-04 11 2.21E-05 20% Pass 25 4.390 54 l .09E-04 10 2.0lE-05 19% Pass 26 4.457 54 l.09E-04 10 2.0lE-05 19% Pass 27 4.524 51 l.03E-04 10 2.0lE-05 20% Pass 28 4.591 47 9.45E-05 10 2.0lE-05 21% Pass 29 4.658 45 9.05E-05 9 1.81E-05 20% Pass 30 4.724 43 8.65E-05 9 1.81E-05 21% Pass 31 4.791 41 8.24E-05 9 l .81E-05 22% Pass 32 4.858 39 7.84E-05 9 l .81E-05 23% Pass 33 4.925 39 7.84E-05 9 1.81E-05 23% Pass 34 4.992 38 7.64E-05 8 1.GlE-05 21% Pass 35 5.059 38 7.64E-05 8 l.61E-05 21% Pass 36 5.125 38 7.64E-05 8 l.61E-05 21% Pass 37 5.192 37 7.44E-05 7 l.41E-05 19% Pass 38 5.259 36 7.24E-05 6 1.21E-05 17% Pass 39 5.326 35 7.04E-05 6 l.21E-05 17% Pass 40 5.393 33 6.63E-05 6 1.21E-05 18% Pass 41 5.460 32 6.43E-05 6 1.21E-05 19% Pass 42 5.526 30 6.03E-05 6 1.21E-05 20% Pass 43 5.593 28 5.63E-05 6 l.21E-05 21% Pass 44 5.660 25 5.03E-05 6 l.21E-05 24% Pass 45 5.727 24 4.83E-05 6 l.21E-05 25% Pass 46 5.794 23 4.62E-05 6 l.21E-05 26% Pass 47 5.861 23 4.62E-05 6 l.21E-05 26% Pass 48 5.927 23 4.62E-05 6 l.21E-05 26% Pass 49 5.994 23 4.62E-05 6 l.21E-05 26% Pass LA COSTA TOWN SQUARE BASIN 2-SWMM Pre-project Interval Flow (cfs) so 6.061 51 6.128 52 6.195 53 6.262 54 6.328 55 6.395 56 6.462 57 6.529 58 6.596 59 6.663 60 6.729 61 6.796 62 6.863 63 6.930 64 6.997 65 7.064 66 7.130 67 7.197 68 7.264 69 7.331 70 7.398 71 7.465 72 7.531 73 7.598 74 7.665 75 7.732 76 7.799 77 7.866 78 7.932 79 7.999 80 8.066 81 8.133 82 8.200 83 8.267 84 8.333 85 8.400 86 8.467 87 8.534 88 8.601 89 8.668 90 8.734 91 8.801 92 8.868 93 8.935 94 9.002 95 9.069 96 9.135 97 9.202 98 9.269 99 9.336 100 9.403 Pre-project Hours 23 23 22 21 21 20 18 18 18 18 16 14 11 11 10 10 9 9 8 8 7 7 7 7 7 7 7 7 7 7 7 6 6 6 6 6 6 6 6 6 6 6 6 6 5 5 5 5 5 5 5 Pre-project% Post-project Post-project% Percentage Pass/FaH Time Exceeding Hours Time Exceeding 4.62E-05 6 1.21E-05 26% Pass 4.62E-05 6 1.21E-05 26% Pass 4.42E-05 6 1.21E-05 27% Pass 4.22E-05 6 1.21E-05 29% Pass 4.22E-05 6 1.21E-05 29% Pass 4.02E-05 6 1.21E-0S 30% Pass 3.62E-05 6 1.21E-05 33% Pass 3.62E-05 6 1.21E-05 33% Pass 3.62E-05 6 1.21E-0S 33% Pass 3.62E-05 6 1.21E-05 33% Pass 3.22E-05 6 1.21E-05 38% Pass 2.81E-05 6 1.21E-05 43% Pass 2.21E-05 6 1.21E-05 55% Pass 2.21E-05 6 1.21E-05 55% Pass 2.0lE-05 6 1.21E-05 60% Pass 2.0lE-05 6 1.21E-05 60% Pass 1.81E-05 6 1.21E-05 67% Pass 1.81E-05 6 1.21E-05 67% Pass 1.61E-05 6 1.21E-05 75% Pass 1.61E-05 6 1.21E-05 75% Pass 1.41E-05 6 1.21E-05 86% Pass 1.41E-05 6 1.21E-05 86% Pass 1.41E-05 6 1.21E-05 86% Pass 1.41E-0S 6 1.21E-05 86% Pass 1.41E-05 6 1.21E-0S 86% Pass 1.41E-05 6 1.21E-05 86% Pass 1.41E-05 5 1.0lE-05 71% Pass 1.41E-05 5 1.0lE-05 71% Pass 1.41E-05 5 1.0lE-05 71% Pass 1.41E-05 5 1.0lE-05 71% Pass 1.41E-05 4 8.04E-06 57% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-0S 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-0S 4 8.04E-06 67% Pass l .21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.21E-05 4 8.04E-06 67% Pass 1.0lE-05 4 8.04E-06 80% Pass 1.0lE-05 4 8.04E-06 80% Pass 1.0lE-05 4 8.04E-06 80% Pass l.0lE-05 4 8.04E-06 80% Pass 1.0lE-05 4 8.04E-06 80% Pass 1.0lE-05 4 8.04E-06 80% Pass l.0lE-05 4 8.04E-06 80% Pass ATTACHMENT 2 -Elevation vs. Area Curves vs. Discharge Curves to be used in SWMM Elevation vs. Area For the portion of the flow diverted in the LID Control to the receiving detention basin, a pond is used to route the hydrographs. The elevation vs area curve in the model is calculated in Excel and imported into the model at a 0.1 ft interval range. Elevation vs Discharge The total discharge peak flow is imported from an Excel spreadsheet that calculated the elevation vs discharge of the multiple outlet system. The orifices have been selected to maximize their size while still restricting flows to conform to the required 10% of the Q2 event flow as mandated in the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. While we acknowledge that these orifices are small, to increase the size of these outlets would impact the basins' ability to restrict flows beneath the HMP thresholds, thus preventing the BMP from conformance with HMP requirements. In order to prevent blockage of the orifices, a debris screen will be fitted to the base invert of the lower orifices located within the detention basin. Regular maintenance of the riser and orifices will be performed to ensure potential blockages are minimized. A detail of the orifice and riser structure is provided in Attachment 5 of this attachment. The stage-storage and stage- discharge calculations have been provided on the following pages. ATTACHMENT 3-Biofiltration Details ATTACHMENT 4 -SWMM Input Data (Existing and Proposed Models) POC2 -EX DMA 2-EX (Onsite) Offsite Commercial O'Day Soil Type D D Area (AC) 2.5 7.8 Flowpath (ft) 500 782 %Slope 2 3 %Impervious 0 90 Suction Head (in) 9 9 Conductivity (in/hr) 0.025 0.01875 Initial Deficit 0.33 0.33 POC2 -PR DMA 2 onsite Offsite Commercial O'Day Soil Type D D Area (AC) 4.95 7.8 Flowpath (ft) 1012 782 %Slope 2 3 %Impervious 68 90 Suction Head (in) 9 9 Conductivity (in/hr) 0.01875 0.01875 Initial Deficit 0.33 0.33 ATTACHMENTS -SWMM Screens and Explanation of Significant Variables Attached, the reader can see the screens associated with the EPA-SWMM Model in both pre- development and post-development conditions. Each portion, i.e., sub-catchments, outfalls, storage units, LID controls for the bio-retention cells, ponding on top of the bio-retention (modeled as a storage unit), weir as a discharge, and outfalls (point of compliance), are also shown. Variables for modeling are associated with typical recommended values by the EPA-SWMM model, typical values found in technical literature. Recommended values for the SWMM model have been attained from the City of Carlsbad BMP Manual. Currently, no recommended values have been established by the San Diego County HMP Permit for the SWMM Model. Soil characteristics of the existing soils were determined from the USGS sources. Some values incorporated within the SWMM model have been determined from the professional experience of H&A using conservative assumption that have a tendency to increase the size of the needed BMP and also generate a long-term runoff as a percentage of rainfall similar to those measured in gage stations in Southern California by the USGS. Description of model parameters and assumptions: N-lmperv -Manning's N for impervious surfaces 0.012 (typical) N-Perv -Manning's N for pervious surfaces 0.15 (typical) Dstore-lmperv-Depth of depression storage on impervious area (in) 0.05 (typical) Dstore-Perv -Depth of depression storage on pervious area (in) 0.1 (typical) %Zero-lmperv -Percentage of impervious area with no depression storage(%) 25 (typical) Suction Head -Soil capillary suction head (in) Conductivity -Soil saturated hydraulic comfuctivity (in/hr) -75% of these values if subcatchment is graded/compacted Initial Deficit -Initial moisture deficit (fraction) Soil Type Suction Head Conductivity Initial Deficit A 1.5 0.3 0.30 B 3 0.2 0.31 C 6 0.1 0.32 D 9 0.025 0.33 NOTE : These values are based on City of Carlsbad's BMP Manual in Appendix G. POC 2 -Pre-Developed Condition ■ SWMM S.1 • 1204·POC2·EX•OCEANSIOE-GAUGE.inp -D X File Edit v;.,. Project R,po• Tools Window Holp D~liil.llill A?Q •l {]JE~l!il.r-JL ~,Ii'~ 1\7 i:,.. a o <1\. '.c\. l=C s 'i?■O'l ◊GI-C?Otet0T , Project .... : • Sludy-Mop 1~ TrtJe/Notes I Options Clim.tok,gy v Hyd,ology Rlin G11gu ---OCEANSIDE Aquifers i5_ij SnowP11cb Unit Hydrogr•phs LID Controls > Hydrtulks > Qu,lity > Curves OFFSITE-COMMERCIAL-O'OAY Time Series ! TimeP11ttems Mapl11bt:ls DMA2-EX(ONSITE) + -"' • • ti • Subutchmenb OfFSITE·COMMERCIAL·O'OA POC2-Existing y V < ) Auto-lmgth: Off • I Off,_ Dep1h .., I Flow Units: CFS •lq I Zooml~k 100% I 1,v, 1450.Sll. 1111.421 Rain Gage OCEANSIDE a Outfall POC2-Existing a· I Property I Value l Property Value: Name :OCEANSIDE Name POC2-Existing X-Coordinate 14n.016 X•Coordinate 1080.745 ¥-Coordinate 15381.329 Y•Coordinate 7566.061 Description Description Tag Tag Rain Format INTENSITY Inflows NO Time Interval 1:00 Treatment NO Snow Catch factor 1.0 lnv,rtEI. 0 Data Source TIMESERJES Tid,Gate NO Route lo Type FREE raedOulfol • File Name foed Stag• 0 • Station ID TKIIIOulfll -Rain Units IN Curve Name Tome Series Outfd Series Name User-assigned name of rain gage User-assigned name of outfall Subcatchment DMA2-EX(ONSITE) Subcatchment OFFSITE-COMMERCIAL-O'DAY Property Value Property Value Name DMAl-EX(ONSITE) Name OFFSITE-COMMERCIAL-O'D~ X-Coordinate 1456.224 X-Coordinate 1082.535 ¥-Coordinate 7865.049 ¥-Coordinate 17946.659 Description t Tag Description Tag l Rain Gage !OCEANSI DE Rain Gage OCEANSIDE Outlet j POC2-Existing Area 12.s Outlet POC2-Existing Area '1.8 Width 500 Width 1200 %Slope 12 %Slope 5 %1mperv 0 %1mperv 85 N-lmperv 0.012 N-lmperv 0.01 2 N-Perv 0.15 N-Perv 0.15 Dstore-lmperv 0.05 Dstore-lmperv 0.05 Dstore-Perv 0.10 Dstore-Perv 0.1 %Zero-lmperv 25 %Zero-lmperv 25 Subarea Routing OUTLET Subarea Routing OUTLET Percent Routed 100 Percent Routed 100 Infiltration GREEN_AMPT _:_J Infiltration GREEN_AMPT _:_J Groundwater NO Groundwater NO Snow Pack Snow Pack LID Controls 0 LID Controls 0 Land Uses 0 Land Uses 0 Initial Buildup NONE Initial Buildup NONE Curb Length 0 Curb Length 0 Infi ltration Editor X Infiltration Editor X Infiltration Method GREEN_AMPT Infiltration Method GREEN_AMPT " Property Value Suction Head 9 Property itlue Suction Head Conductivity 0.1 Conductivity 0.01875 Initial Deficit 10.32 Initial Deficit 10,33 Soil capillary suction head (inches or mm) Soil capillary suction head (inches or mm) C ] [ [ --I OK Cancel Help I [ OK [ C<lncel 7 [ Help J POC 2 -Developed Condition ■ SWfvlM 5.1 l204-POC2·PfHX.EAASIDE ,,ip {Study Ana MapJ □ X f-:._,_,.._,_•_•_v ____ ., _ _.'---"''-"°"--r-__ w_,,._.., __ .,..---'-P----=~-----------------------------'-·-" • Clr.i.U• llli ll ?{]e ~IE~l!i!lllltf};!di"~ S'■OV ◊Gl-v'ilH:10T T!UdNotn Opt;on, Climatok,gy > Hyd,ology > Hychulia > Qu,Jity v Curves Control Curws r-PumpCUIYff btingCul\lfl Sh&peCurws StonttC....rva Tid,l(urws TIITleSaies Ttme.Plttems M,plabds DMA2-PR(ONSITE) '!I OFFSITE-COMMERCIAL-ODAY •········· ·•··· BASIN-2 ··r DIV-2 ):(51 OCEANSIDE 121 Auto-length: Off • I Offstts: Depth • I Flow Units: CFS • I j Zooml,vtl: 100% I ~Y:2157.75).4l-47.191 Rain Gage OCEANSIDE JPropfflY Name X-Coordinate Y-Coordinate Description Tag Rain Format Time Interval Snow Catch Factor Data Source TIMESERIESc -Series Name DATA RI.£: • File Name • Station 10 · Rain Units \Value EANSIDE 14n.016 5381329 INTENSITY 1:00 1.0 TIMESERIES OCEANSIDE-RAIN IN User-assigned name of rain gage II I ------------------Outfall POCl-Proposed •i Property Value Name POC 1-Proposed X-Coordinate 1474.848 V • Coordinate 4329.925 Description Tag Inflows NO Treatment NO Invert El. 0 Tide Gate NO Route To Type FREE F"med Outfal Fixed Stage 0 TldllOutfll Curve Name Time Series Oulfal Series Name X coordinate of outfall on study area map Subcatchment BASIN-2 Subcatchment OFFSITE-COMMERCIAL-OOAY Subcatchment DMA2-PR(ONSITE) I Property lvalu• II Property !valu• !I Property lvalu• ' Name BASIN-2 IName OFFSITE-COMMERCIAL-DDA Nam• DMA2-PR(ONSITE) X-Coordinat, 922.814 X-Coordinat• 577.890 X-Coordinat• 923.227 V-Coordinat• 5001.678 V-Coordinat• 'm8.955 V-Coordinato 5193.153 Dtscription Dtscription Dtseription Tag Tag Tag Rain Gag• OCEANSIDE Rain Gag• OCEANSIDE Rain Gag• OCEANSIDE Outlet DIV-2 Outlet SASIN-2 Outlet BASIN-2 Aru .18 Aru 7.8 Aru 4.95 Width 50 Width 1200 Width 1012 %Slop• 0.1 %Slop• 7.8 %Slop• 2 %1mp•rv 0 %lmptrv 85 %lmptrv 80 N·lmptrv 0.012 N·lmp•rv ro.012 N-lmp•rv 0.012 N-Ptrv 0.15 N-P•rv 0.15 N-P•rv 0.15 Ostore-lmperv 0.05 Dstor ... lmp•rv Dstort-lmperv 0.05 0.05 l Dstore-Perv Dstor ... P,rv 0.1 Dstor ... Perv 0.1 %Ztro-lmptrv 25 %Zero-lmp•rv 25 %Zero-lmp•rv 25 Subaru Routing Ol/TLET Subaru Routing Ol/TLET Subaru Routing OUTLET P,rc,nt Routed 100 Percent Routed 100 P,rc,nt Routed 100 Infiltration GREEN_AMPT _:J Infiltration Groundwater NO GREEN_AMPT _J Infiltration GREEN_AMPT _J Groundwater NO Groundwater NO I Snow Pack Snow Pack Snow Pack LID Controls LID Controls 0 LID Controls 0 land Uses 0 Initial Buildup NONE Land Usts 0 Land Usts 0 Curb Ltngth 0 Initial Buildup NONE Initial Buildup NONE Infiltration parameters (click to tcfrt) Curb L,ngth 10 Curb Length 0 Infiltration Ed,tor X Infiltration Editor X Infiltration Editor X Infiltration Method GREEN_AMPT Infiltration Method GREEN_AMPT Infiltration Method GREEN_AMPT Prop•rty lvalu• I Property IValu• I Property IVaiu• Suction H,ad 11,5 Suction Htad 19 ]Suction Hud 19 Conductivity 0.3 Conductivity 0.01875 I Conductivity 0.075 initial Deficit 0.3 Initial Deficit 0.33 llnitial Deficit OJ2 EXPLANATION OF SELECTED VARIABLES Parameters for the pre-and post-developed models include soil type D in accordance with the San Diego County Hydrology Manual and the USGS Soil Survey Map (attached at the end of this appendix). Suction head, conductivity and initial deficit corresponds to average values expected for the soil types, according to sources consulted, professional experience, and approximate values obtained from the BMP Design Manual. H&A selected infiltration values, such that the percentage of total precipitation that becomes runoff, is realistic for soil type D and slightly smaller than measured values for Southern California watersheds. Selection of a Kinematic Approach: As the continuous model is based on hourly rainfall, and the time of concentration for the pre-development and post-development conditions is significantly smaller than 60 minutes, precise routing of the flows through the impervious surfaces, the underdrain pipe system, and the discharge pipe was considered unnecessary. The truncation error of the precipitation into hourly steps is much more significant than the precise routing in a system where the time of concentration is much smaller than 1 hour. Sub-catchments BASIN-2. The area of Prop-X + BF-X must be equal to the area of the development tributary to that particular bio-retention facility. Five (5) decimal places were given regarding the areas of the biofiltration to insure that the area used by the program for the LID subroutine corresponds exactly with these tributaries. BIOFILTRATION BASIN 2 LID Usage Editor LID Control Name Detailed Report File (Optional) .... ---·-. -LID Control Editor X ControfN•me JeF-2 Surf•ce Soil Storage Dr•in LID Type I st<>-Retffltion CeU vi Berm Height ~ (in.otmm) Vegdation Volume ~ Fraction Surf.ce Roughness c=I (Mannings n) Surface Slope c=I (pet"centJ ·opttona.l OK 1 [ Conul Help LIO Control Editor X Control N1me: 1sF-<1 Sutface Soil Storage Dnin LID Type j Bio-RetrntK>n Cell vi Thtclcness ~ (in.or mm) Votd R,tio ~ (Voids/ Solids) S«page R,te c=J (in/hr or mm/hr) Clogging Factor c=J OK J Help X 0 LID Occupies Full Subcatchment Area of Each Unit (sq ft or sq m) 14134 I Number of Units I, I':' % of Subcatchment Occupied S2.7 Surface Width per Unit (ft or m) 1,00 % Initially Saturated I, % of Impervious Area Treated 1,00 Send Drain Row To: (leave blank to use outlet of current subcatchment) 0 Return all Outflow to Pervious Area OK LID Control Editor Control N11me:. JeF-<1 LID Type I Bio-Retffltion Cdl vi .. OptioMI OK 1 C.ncol l Help LID Controt Editor ControlN1me leF-,1 LIO Type: j Bio-Retention Cell vi •Optional OK C•ncef ] Cancel ] [ Help Swbu Soil Stonge 0,.., Thttknes.s E::J (in.or mm) Porosity E=i (volume fraction) Fidd Capacity §=i (volume fr-action) Wilting Point ~ (volume f,..ction) Conductivity ~ (in/hr or mm/hr) Conductivity ~ ~ope Su<tton Hud ~ (in.or mm) Surface Soil Stor•~ Onin Flow Cotffte~t• ~ Flow Exponent ~ Offset Height c=J (in.or mm) ~ •uruts •rt for flow in either in/hr Of mm/hr, use O If there is no dn1in. l X X LID Control Editor: Explanation of Significant Variables BIORETENTION Height: The storage depth variable within the SWMM model is representative of the storage volume provided beneath the engineered soil and mulch components of the biofiltration facility. This storage volume is comprised of a gravel located bed beneath a layer of engineered soil. Porosity: A porosity value of 0.4 has been selected for the model. The amended soil is to be highly sandy in content in order to have a saturated hydraulic conductivity of approximately 5 in/hr. H&A considers such a value to be slightly high; however, in order to comply with the HMP Permit, the value recommended by the Copermittees for the porosity of amended soil is 0.4, per Appendix A of the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. Void Ratio: The ratio of the void volume divided by the soil volume is directly related to porosity as n/(1-n). As the underdrain layer is composed of gravel, a porosity value of 0.4 has been selected, which results in a void ratio of 0.4/(1-0.4) = 0.67 for the gravel detention layer. Clogging factor: A clogging factor was not used (0 indicates that there is no clogging assumed within the model). The reason for this is related to the fairness of a comparison with the SOHM model and the HMP sizing tables: a clogging factor was not considered, and instead, a conservative value of infiltration was recommended. Drain (Flow) coefficient: The flow coefficient in the SWMM Model is the coefficient needed to transform the orifice equation into a general power law equation of the form: (1) where q is the peak flow in in/hr, n is the exponent (typically 0.5 for orifice equation), H D is the elevation of the centroid of the orifice in inches (assumed equal to the invert of the orifice for small orifices and in our design equal to O) and H is the depth of the water in inches. The general orifice equation can be expressed as: Q = ~C D: Jz (H-Hp) 4 g 14-4 g 12 (2) where Q is the peak flow in cfs, D is the diameter in inches, cg is the typical discharge coefficient for orifices (0.61-0.63 for thin walls and around 0.75-0.8 for thick walls), g is the acceleration of gravity in ft/s2, and Hand H D are defined above and are also used in inches in Equation (2). BASIN 2 Storage Unit Stor-A ■ I Property I value I Name Stor-A X-Coordinate 921.710 V-Coordinate 4428.590 Description Tag Inflows NO Treatment NO Invert El. 0 Max. Depth 6 Storage Curve Editor X Initial Depth 0 Curve Name Ponded Area 42385 !easin-2 Evap. Factor 0 Descrif!ion I I ,tiJ Seepage Loss NO Depth Area ,., Virw ... Storage Curve TABULAR (ft) (ft2} Functional Curve 1 0 11229 Load ... 2 1 12121 Coefficient 1000 3 2 13013 Exponent 0 Save .•• 4 3 13544 Constant 0 5 4 14074 6 5 15168 Tabular Curve 7 6 16300 OK Curve Name Basin-2 J 8 7 17491 9 Cancel 10 11 ... Help! Outlet Outlet-2 a Rat,ng Curve Editor X I Property I Value I Curve Name Name Outlet-2 IDisch-2 Inlet Node Stor-A Descrietion Outlet Node POC2-Proposed I 1~ Description Outflow ,., View ... Tag (CFS) Inlet Offset 0 0 Load. .. Flap Gate NO 1 0.6 Rating Curve TABULAR/DEPTH 3 2 2.6 Save. .. FunctioNI Curve 4 2.5 27.3 5 3 32.3 Coefficient 10.0 6 4 40.5 Exponent 0.5 7 5 47.3 OK T.bular Curve 8 6 53.2 Curve Name Disch-2 9 7 58.5 Cancel 10 User-assigned name of outlet 11 " Help Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing Factors I I I I l ___ .. .... i EXPLANATION t. -Pt-•-eonc..... La<e Wohlfonl 8;H,n t -l.lrdbefgh e.,., I • =,,,_a .... rn1111 ·~ '------------------------------~ Figure G.2-1: Appropriate Rain Gauge for Project Sites Table G.2-1: Runoff factors for surfaces draining to BMPs for Hydromodification Sizing Factor Method Surface Runoff Factor Roofs 1.0 Concrete 1.0 Pervious Concrete 0.10 Porous Asphalt 0.10 Grouted Unit Pavers 1.0 Solid Unit Pavers on granular base, min. 3/16 inch joint space 0.20 Crushed Aggregate 0.10 Turf block 0.10 Amended, mulched soils 0.10 Landscape 0.10 G-23 February 2016 BMP Sizing Spreadsheet V2.0 Project Name: La Costa Town Square Parcel 3 Project Applicant: TRC Retail Jurisdiction: City of Carlsbad Parcel (APN): 223-050-73 Hydrologic Unit: Carlsbad Rain Gauge: Oceanside Total Project Area (sf): 217,800 Channel Susceptibility: Low BMP Sizing SprHdsheet V2.0 Project Name: La Costa Town Square Parcel 3 Hydrologic Unit: C.rlsbad Project Applicant TRC Retail Rain Gauge: Oceanside Jurisdiction: City of Carlsbad Total Project Area: 217,800 Parcel (APN): 223-050-73 low Flow Threshold: O.SQ2 BMPName: BF-1 BMPType: Bioftttration w/ Impermeable Uner BMP Native Soil Type: C BMP Infiltration R.lte (in/hr}: 0.08 Areas Draining to BMP HMP Sizing Factors Minimum BMP Size OMA Post Project Runoff Factor Surface Volume Subsurface Volume Name Area (sf) Soll Type Pre-project Slope Surface Type (Table G.2-1)1 Surface Area Surface Volume Subsurface Volume Surface Area (sf} {cf} (cf} 1 9,000 C Steep Pavement 1.0 0.065 0.0542 0.039 585 488 351 1 29,800 C Steep Landsc.ape 0.1 0.065 0.0542 0.039 194 162 116 Total BMP Area 38,800 Minimum BMP Size 778.7 649 467 Proposed BMP Size• 1500 750 900 Soil Matrix Depth 18.00 in Minimum Ponding Depth 5.19 in Maximum Ponding Depth 50.02 in Selected Ponding Depth 6.00 in Notes: ------1. Runoff factors which are used for hydromodification management flow control {Table G.2-1) are different from the runoff factors used for pollutant control BMP sizing (Table 8.1-1). Table references are taken from the San Diego Region Model BMP Design Manu Describe the BMP's in sufficient detail in your POP SWQMP to demonstrate the area, volume, and other criteria can be met within the constraints of the site. SMP's must be adapted and applied to the conditions specific to the development project such as unstabh~ slopes or the lack of available head. Designated Staff have final rev;ew and approval authority over the project design. This BMP Sizing Spreadsheet has been updat'ed In conformance with the San Diego Region Model BMP Design Manual, February 2016. For questions or concerns please contact the jurisdiction in which your project is located. BMP Sizing Spreadsheet V2.0 Project Name: osta Town Square Pare Hydrologic Unit: Carlsbad Project Applicant: TRC Retail Rain Gauge: Oceanside Jurisdiction: City of Carlsbad Total Project Area: 217,800 Parcel (APN}: 223-050-73 Low Flow Threshold: 0.5Q2 BMPName BF-1 BMPType: Biofiltration w/ Impermeable Liner OMA Rain Gauge Pre-developed Condition ~ Sizing Factor OMA Area (ac} Orifice Flow -%~ Orifice Area Name Soil Type Cover Slope (ds/ac} (cfs} (in2) 1 Oceanside C Scrub Moderate 0.185 0.207 0.019 0.47 1 Oceanside C Scrub Moderate 0.185 0.684 0.063 1.55 Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub Scrub 0.082 2.01 1.60 Tot. Allowable Tot. Allowable Max Orifice Orifice Flow Orifice Area Diameter (cfs} (in2} (in} 0.032 0.79 1.00 Actual Orifice Flow Actual Orifice Area Selected Orifice Diameter (cfs) (in2} (in) Drawdown (Hrs) 6.5 :J 6' PLANTABLE/ RETAINING WALL EXISTING MODIFIED WING-TYPE HEADWALL PE,,,-------.. D-34 OF SDRSD PER 409-4C BASIN 2 NOT TO SCALE 5'FENCE~ EXISTING DRAINAGE EASEMENT I I I /DAYLIGHT .:1 DETENTION BASIN 270.4 FG BASIN VOLUME: 85,400 CF DAYLIGHT~ 1% GENERAL LOCATION OF UNDERDRAIN BASIN 2 -CROSS-SECTION A-A EXISTING MODIFIED TRIPLE TYPE 'G' CATCH BASIN PER D-08 OF SDRSD PER 409-4C '3.5' ' NOT TO SCALE EXISTING GROUND;270.2 27D.2 FG ~ SEE TYPICAL BIOFILTRATION BASIN DETAIL 18" PLANTING MIX 5IN/HR MIN PERC RATE ARMORED BERM BOTTOM MIN. 3" AGGREGATE BELOW SUBDRAIN TYPICAL BIOFILTRATION BASIN DETAIL (PVT) (BASIN 2) NOTE: ELEVATIONS SHOWN ARE ON NAVO 88. ELEVATIONS ON DRAWING 409-4C ARE ON NGVD 29 (2, 17' LOWER) NOT TO SCALE VERTICAL CLEANOUT WITH LOCKABLE CAP AT THE END OF EACH SUBDRAIN. EXTEND ABOVE FINISH GRADE. V (MIN {TYPICAL) _ 3H:1 EXISTING RIP-RAP .=.:i=-'' _::!i.'...:_',...,.- ----:t"c'' ,· I AMEND 2017-0012/CT2017-0003/PUD2017-0004/SDP2018-0018 ·~-c-~·-----------~--- BASIN 1 GENERAL LOCATION OF UNDERDP.AIN NOT TO SCALE BIOFILTRATION BASIN 264.7 FG SPILLWAY 261.7 FG BASIN BOTTOM i-.1 ~PER BIOFILTRA TION BASIN 1 DETAIL BASIN 1 -CROSS-SECTION B-B NOT TO SCALE VERTICAL CLEANOUT WITH LOCKABLE CAP AT THE END OF EACH SUBDRAIN. EXTEND ABOVE FINISH GRADE. (rt'PICAL) 12" AGGREGATE STORAGE LAYER: 9" CLASS 2 PERMEABLE PER CALTRANS SPEC 68-1.025 WITH 3" PEA GRAVEL FILTER COURSE LA YER AT THE TOP. CLASS 3 PERMEABLE & PEA GRAVEL SHALL BE WASHED AND FREE OF FINES. 30 MIL PVC LINER (IMPERMEABLE). XJSTING18" HOPE OUTFLOW 261.8 f"L PER DWG 474-7A UPDTAED TO NGVD 88 MIN. 3" AGGREGATE BELOW SUBDRAIN BOTTOM TYPICAL BIOFILTRATJON BASIN DETAIL {PVT) (BASIN 1) NOTE: ELEVATIONS SHOWN ARE ON NAVO 88. ELEVATIONS ON DRAWING 474-7A ARE ON NGVD 29 (2.17' LOWER) NOT TO SCALE · :..--· BASIN & DETAILS ,..____ -------y~ -- PREPARED BY: VESTING TENTATIVE MAP AND PLANNED DEVELOPMENT PERMIT HUNSAKER LA COSTA TOWN SQUARE & ASSOCIATES SAN DIECO, I NC PARCEL 3 Pl/rl.NNING 9707 Waples Street ENGINEERING San Diego, Ca 92121 SURVEYING PH(858)558-450-0· FX(858)558-1414 CITY OF CARLSBAD, CALIFORNIA R: \ 1204 \&PlnLa Costa Town Square TM Sht 00.dwg[ $(GEN AR,??) SHEET 8 OF 12 c:, c:, c:, I :g ::::i ~ c:i ;;,; .... ATTACHMENT 3 Structural BMP Maintenance Information Use this checklist to ensure the required information has been included in the Structural BMP Maintenance Information Attachment: Preliminary Design/ Planning/ CEQA level submittal: Attachment 3 must identify: ~ Typical maintenance indicators and actions for proposed structural BMP(s) based on Section 7.7 of the BMP Design Manual Final Design level submittal: Attachment 3 must identify: □ Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s) □ How to access the structural BMP(s) to inspect and perform maintenance □ Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds) □ Manufacturer and part number for proprietary parts of structural BMP(s) when applicable □ Maintenance thresholds for BMPs subject to siltation or heavy trash(e.g., silt level posts or other markings shall be included in all BMP components that will trap and store sediment, trash, and/or debris, so that the inspector may determine how full the BMP is, and the maintenance personnel may determine where the bottom of the BMP is . If required, posts or other markings shall be indicated and described on structural BMP plans.) □ Recommended equipment to perform maintenance □ When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management TABLE 7-2. Maintenance Indicators and Actions for Vegetated BMPs Typical Maintenance Maintenance Actions lndicator(s) for Vegetated BMPs Accumulation of sediment, litter, or Remove and properly dispose of accumulated materials, without debris damage to the vegetation. Poor vegetation establishment Re-seed, re-plant, or re-establish vegetation per original plans. Overgrown vegetation Mow or trim as appropriate, but not less than the design height of the vegetation per original plans when applicable (e.g. a vegetated swale may require a minimum vegetation height). Erosion due to concentrated irrigation Repair/ re-seed/ re-plant eroded areas and adjust the irrigation flow system. Erosion due to concentrated storm Repair/re-seed/re-plant eroded areas, and make appropriate water runoff flow 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 City Engineer shall be contacted prior to any additional repairs or reconstruction. Standing water in vegetated swales used Make appropriate corrective measures such as adjusting irrigation for pretreatment and/or site design system, removing obstructions of debris or invasive vegetation, BMPs loosening or replacing top soil to allow for better infiltration, or minor re-grading for proper drainage. If the issue is not corrected by restoring the BMP to the original plan and grade, the City Engineer shall be contacted pnor to any additional repairs or reconstruction. Standing water m bioretention, Make appropriate corrective measures such as biofiltration with partial retention, or inspecting/unclogging orifice opening, adjusting irrigation system, biofiltration areas, or flow-through removing obstructions of debris or invasive vegetation, clearing planter boxes* for longer than 96 hours underdrains (where applicable), or repairing/replacing clogged or following a storm event** compacted soils. Obstructed inlet or outlet structure Clear obstructions. Damage to structural components such Repair or replace as applicable. as weirs, inlet or outlet structures **These BMPs typically include a surface ponding layer as part of their function which may take 96 hours to drain following a storm event. ATTACHMENT 4 City standard Single Sheet BMP (SSBMP) Exhibit [Use the City's standard Single Sheet BMP Plan.] r) C) ' -/, -'S?, _L~:,; ~= -- --..:;; .. I I \ ., ---,/ ..... _r-".'.I ,;:...7~-~,--;"~\-:~~~:1l?.:~ / / ,·'' /-,<,'- '/,~-'/-,., . ~-~ ,,;,·:,/ ,,,, . / . . . ' , -· s.-/,>-;: ;?'>.-.:· 'lf '\]~ii ~ ~· i I I ,ii~,c,i/,!t 40,\i .. ,P • ~ ' ' ~---,-;:;: / , r /,,,~ ,_ ·--\~-i·1Y:·;.,:-; __ ., < ,.,._;..: ,_, ,..-:~ ,-,,.-; / , r_ •' ·;:;i:-,~--::,.·'_. '.--;; _, .· . >~·:·:~<· : :~•%:t¾ 0 .0···- .-_,-':<:.;:>:-.. ,,/ ; ----~ - BMP ID# SWQMPNO~-~xxxx~--- PARTY RESPONSIBLE FOR MAINTENANCE: NAME_~T~R~C~R=ET~A~IL~---- ADDRESS 4695 MACARTHUR COURT SUITE 700 NEWPORT BEACH, CA 92260 PHONE NO. (949)662-2144 PLAN PREPARED BY: NAME Raymond L. Martin COMPANY Hunsaker & Associates ADDRESS 9707 Waples Street San Diego, Ca 92121 PHONE NO. (858)558-4500 BMP NOTES: CONTACT_CA_R_L_OS_P_AL_OF_O_X_ SIGNATURE CERTIFICATION _____ _ 1. THESE BMPS ARE MANDATORY TO BE INSTALLED PER MANUFACTURER'S RECOMMENDATIONS OR THESE PLANS. 2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING TYPES WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY INSPECTION STAFF HAS INSPECTED THIS PROJECT FOR APPROPRIATE BMP CONSTRUCTION AND INSTALLATION. 5. REFER TO MAINTENANCE AGREEMENT DOCUMENT. 6. SEE PROJECT SWMP FOR ADDITIONAL INFORMATION. BMP TABLE BMPTYPE SYMBOL CASQA NO. QUANTITY DRAWING NO. HYDROMODIFICATION & TREATMENT CONTROL CD-@ BIOFILTRATION §gogo~o~¥1 TC-32 8,821 (BOTTOM) AREA o~o<?o~o0 --sF. LOW IMPACT DESIGN (L.1.D.) ® PRESERVATION OF ~ EC-2 1 EA. EXIST. VEGETATION SOURCE CONTROL SHEET NO.(S) INSPECTION * MAINTENANCE * FREQUENCY FREQUENCY SEMI-ANNUALLY MONTHLY ANNUALLY AS NEEDED \ :~g-..:'_;;..-tf:.<'.;>;:" .. ;._·· .. ,, .• ;; ... • ..... ,,,,::cc:~-=-.... .. _ .. :;'--_·· • -~e. •. ©-© STENCILS NO DUMPING SD-13 1 EA. ANNUALLY AS NEEDED DRAINS TO OCEAN 0 STREET SWEEPING ~ SE-7 1 EA. ANNUALLY AS NEEDED -"-,::<;_-::-.:f.------====-"""~~ <~"\:~:. ;:.?;,1/:::::C---·•· , I j 0 40 BO 120 SCALE 1' =40' * CHOOSE FROM THE LIST BELOW FOR COMPLETING THE FIELDS IN THE INSPECTIONS & MAINTENANCE FREQUENCY COLUMNS: ANNUAL SEMI-ANNUALLY QUARTERLY BIMONTHLY MONTHLY AS NEEDED NONE WEEKLY 1 TIME PER YEAR 2 TIMES PER YEAR 3 TIMES PER YEAR 4 TIMES PER YEAR r----------------+--+---11-----!---11 SHEET I CITY OF CARLSBAD I SHEETS I ENGINEERING DEPARTMENT :=:=:'.....::============'-==~ SINGLE SHEET BMP SITE PLAN LA COSTA TOWN SQUARE PARCEL 3 ~=========================⇒===t==±===i==J;:========:::;-;::::======::: RECORD COPY PROJECT NO. XXX DATE REVISION DESCRIPTION INITIAL DATE INITIAL OTHER APPROVAL Cl1Y APPROVAL DATE DRAWING NO. XXX -• ---• ----- -• -.. • .. • --.. .. -... ... ... - .. ATTACHMENT 5 -• • • -- -• - -• -• • • • - -.. -.. - .. - -.. - M Ii SDVOSB.DVB!; February 28, 2017 Mr. Thomas Fitzpatrick Terramar Retail Centers 5973 Avenida Encinas, Suite 300 Carlsbad, California 92008 Subject: LIMITED GEOTECHNICAL INVESTIGATION LA COSTA TOWN SQUARE MULTI-FAMILY HOUSING LA COSTA BOULEVARD CARLSBAD, CALIFORNIA SCST, Inc. Corporal• ~ .. dquarlers 6280 Riverdale Street San Diego, CA 92120 T 877.215.4321 P 619.280.4321 i: 619.280.4717 w www.scst.com SCST No. 16051 SN Report No.1 References: 1.) SCS&T, (2012) "Geotechnical Investigation, La Costa Town Square, Office Development, Carlsbad, California~ dated July 31. 2.) SCS&T, (2013) "Interim As-Graded Geotechnical Report, La Costa Town Square, Office Development, La Costa Avenue, Carlsbad, California~ Project No. C.T. 08- 07, dated December 23. 3.) Hunsaker & Associates, (2014), "Laterra Product Yield Study/Alt. 13, La Costa Town Square Parcel 3, Carlsbad, California", dated September 29 . Dear Mr. Fitzpatrick: This report presents the findings and conclusions of a limited geotechnical investigation performed by SCST, Inc. (SCST) at the subject site. SCST prepared a geotechnical report (SCS&T 2012, Reference 1 above) for the subject project to provide grading recommendations prior to development. SCS& T observed mass grading the pad to its existing grade and prepared an as-graded report to summarize our observations and testing (SCS&T 2013, Reference 2 above). The purpose of the subject investigation is to provide general updated geotechnical recommendations for future development based on the existing mass graded conditions and the proposed development (Hunsaker & Associates, 2014, Reference 3, above). Specific recommendations can be provided when building details and final grades are established. SCOPE OF WORK The following tasks were performed for this updated report . • Reviewed previously prepared reports • Performed a site reconnaissance Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California February 28, 2017 SCST No. 160518N-1 Page2 • Explored the subsurface conditions by excavating 18 test pits between about 3 to 6 feet deep with a rubber tire backhoe (Appendix I) • Performed laboratory testing consisting of expansion index and corrosivity testing on samples collected during exploration (Appendix II) • Conducted geotechnical analysis and prepared this report summarizing our findings, conclusions, and recommendations. SITE HISTORY AND SURFACE CONDITIONS The site is located in Carlsbad on the north side of La Costa Avenue at the intersection with Calle Timiteo. The site is a graded parcel that was part of the mass grading for the La Costa Towne Square development (SCS&T 2013). Prior to grading, the site was undeveloped and characterized by a north/south trending natural ridge line that sloped to the south. PROPOSED DEVELOPMENT The referenced plans (Hunsaker & Associates) indicate the proposed condominium development will be constructed at approximately existing grade. Desilting basins in the southern half of the site will be filled to finish grade. Cuts may be required at the intersection of the entrance road with Private Drive "B". Excavations will be required for underground utilities. SUBSURFACE CONDITIONS Figure 1, Geologic Map presents the approximate distribution of the geologic materials at the site. Metamorphic rock (Map Symbol Jmv) is exposed in the central portion of the site (Figure 2) and underlies the remainder of the site at depth. The Delmar Formation (Map Symbol Td) overlies the metamorphic rock and is exposed or buried by fill in the northern portion of the site (Figure 2). In the western and eastern portion of the site, the metamorphic rock and Delmar Formation are covered with compacted fill. Logs of test pits excavated in these materials are presented in Appendix I. Fill The fill was placed as part of the mass grading operations and is documented in the Interim As- Graded Geotechnical Report (SCS&T, 2013). The fill encountered in the test pits and discussed in as-graded reports consists primarily of clayey gravel, gravely clay, sandy gravel, silty gravel, sandy fat clay and fat clay. As seen in the test pits (Appendix I), the more granular fill is found within 3 feet of the current surface elevation. The fill exhibits a medium to high expansion potential and is non-to moderately corrosive relative to sulfate exposure (Appendix II). II ■ ■ii -------------------------------------- .. • ---• ---• - ---• - • • • - --.. - --- -... Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California Delmar Formation February 28, 2017 SCST No. 16051BN-1 Page3 The Delmar Formation is comprised of poorly indurated very stiff to hard, sandy clay, and fat clay. The Delmar Formation has a high to very high expansion potential and is non-to moderately corrosive relative to sulfate exposure (Appendix I). Metamorphic Rock The metamorphic rock is comprised of metamorphosed and un-metamorphosed volcanic and sedimentary rock. Exposures in the central portion of the site expose massive, moderately to intensely weathered, moderately fractured rock. In the exploration trenches, the rock is decomposed to clay. Where moderately weathered, the rock will likely need to be blasted or broken with rock breakers. The decomposed metamorphic rock we tested has a high expansion potential and is non-corrosive relative to sulfate exposure (Appendix I). Both moderately weathered and decomposed rock have been differentiated on the Geotechnical Map, Figure 2. LABORATORY TESTING The laboratory testing program consisted of expansion index and corrosivity tests. The results of the laboratory tests, and brief explanations of test procedures, are provided in Appendix II. UPDATED CALIFORNIA BUILDING CODE SEISMIC DESIGN PARAMETERS The site coefficients and adjusted maximum considered earthquake spectral response accelerations in accordance with the 2016 California Building Code are presented below: Site Coordinates: Latitude 33.080459° Longitude -117.232470° Site Class: C Mapped Spectral Response Acceleration at Short Periods, Ss = 1.029g Mapped Spectral Response Acceleration at 1-Second Period, S1 = 0.399g SMs=FaSs = 1.029g SM1=FvS1 = 0.559g Sos=½ SMs = 0.686g So1=½ SM1 = 0.373g PGAM = 0.398g CONCLUSIONS The main geotechnical considerations affecting the future development at the site are: • Difficult excavation conditions in areas underlain by moderately weathered rock • Expansive soil • Locally corrosive soil • Cut/fill transitions below the building pads '1 ■ ■Ii Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California RECOMMENDATIONS February 28, 2017 SCST No. 160518N-1 Page4 The following recommendations are general and preliminary since building details and finish grades will need to be finalized. REMEDIAL GRADING Remedial grading will generally include the following activities: • Excavation of metamorphic rock to a depth of approximately 5 feet below finished pad grade. Excavations should be backfilled with material having an expansion index of 50 or less. • Excavation of formation al materials at lots with cut/fill transitions. The cut portion of the pads typically should be excavated 3 feet below planned bottom of footing elevation. Excavations should be backfilled with material having an expansion index of 50 or less • Excavation of highly expansive material to a depth of approximately 5 feet below finished pad grade. Excavations should be backfilled with material having an expansion index of 50 or less. • Remedial grading excavations in excess of 2 feet deep should not encroach within at least 7 feet from the existing MSE wall on the north side of the site without special grading techniques reviewed by the geotechnical engineer. EXCAVATION CHARACTERISTICS It appears that most excavations can be ripped and excavated to a depth of at least 5 feet below existing grade. Excavations within about 100 feet of the intersection of the entrance and Private Drive "B" may encounter moderately weathered rock. Grading or trenching in these locations may be difficult and rock breakers and blasting may be required for trenching. In addition, oversized, buried hard rock requiring special handling should be anticipated. Conventional heavy equipment in good working order is expected to be able to excavate the fill materials, Delmar Formation and decomposed metamorphic rock on-site. Contract documents should specify that the contractor mobilize equipment capable of excavating and breaking the metamorphic rock. OVERSIZED MATERIAL Excavations into metamorphic rock may generate oversized material. Oversized material is defined as rocks or cemented clasts greater than 6 inches in largest dimension. Oversized material should be broken down to no greater than 6 inches in largest dimension for use in fill. Oversized material may be used in fills in excess of about 5 feet. Oversize material that cannot be used may need to be disposed off-site. m ■ ■ii -------------.. ----------- ------------ -• - -.. - -• -.. -• -• .. • • • .. • --- .. --- -.. ... Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California EXPANSIVE SOIL February 28, 2017 SCST No. 16051BN-1 Pages The existing on-site materials that we tested have a medium to very high expansion potential in accordance with ASTM D 4829. Soil with an expansion index greater than 50, such as material from the Delmar Formation should be kept at least 5 feet below the planned final pad grade elevation, at least 2 feet below hardscape subgrade, and at least 1 0 feet from the face of all fill slopes and retaining walls, or exported from the site . As an alternative to exporting or burying highly expansive soil, the excavated soils can be mixed with cement or lime to reduce their expansion potential. Typically, 5% cement or lime by dry unit weight can be assumed for estimating purposes. The material to be stabilized should not contain rocks or clods larger than 2½ inches in any dimension. Additional testing will need to be performed if this alternative is selected . BULK AND SHRINK ESTIMATES Fills should not be expected to bulk during compaction. Lime treated fills may bulk up to 3%. Delmar Formation and decomposed rock will likely bulk 3 to 5 percent where recompacted or lime treated . Weathered rock will likely bulk 10-15 percent as a fill but will depend on crushing or disposal methods . These estimates are based on our experience on this and other mass grading projects. The actual volume changes will vary due to grading methods and soil changes. The estimates should be verified by testing during grading. CORROSIVE SOIL Representative samples of the current finish grade soils were tested to evaluate corrosion potential and were found to be non-to moderately corrosive relative to sulfate exposure. The test results are presented in Appendix II. The project design engineer can use the sulfate results in conjunction with ACI 318 to specify the water/cement ratio, compressive strength and cementitious material types for concrete exposed to soil. A corrosion engineer should be contacted to provide specific corrosion control recommendations. CUT/FILL TRANSITIONS BENEATH BUILDINGS Some of the planned building pads span a cut/fill transition with a fill differential ranging between about 5 and 15 feet. The cut portion of the pads typically should be excavated 3 feet below planned bottom of footing elevation. The bottoms of the excavation and subgrades beneath fill areas should be sloped toward the street or fill portion of the lot, and away from its center. Subdrains may be needed at the bottom of the excavated areas. Specific recommendations should be made on a case by case basis and will depend on the building details, location, and finish grade elevations. M ■ ■Ii Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California FOUNDATIONS February 28, 2017 SCST No. 160518N-1 Page6 Foundation design will depend on the final as-graded conditions and should be reviewed by the geotechnical consultant during fine grading. Either conventional shallow foundations with special slab designs or post tension slab foundations may be used for foundation materials that have a low expansion index. Conventional Shallow Foundations Shallow spread footings with bottom levels on compacted fill having a low expansion potential should extend at least 18 inches below lowest adjacent finished grade. Post-Tension Slab Foundations One and two story structures can generally be supported on post-tensioned slab foundations with bottom levels on compacted fill having a low expansion index. The slab should be designed by a structural engineer familiar with the design criteria presented in the Post-Tensioning Institutes (PTI), as required by the 2013 California Building Code. Geotechnical parameters for design of post-tension slabs can be provided based on the final as- graded conditions and laboratory testing. PLAN REVIEW Fine grading plans should be reviewed by SCST to see that the recommendations in this update report have been considered. Additional sampling or exploration may be recommended. CLOSURE SCST should be advised of any changes in the project scope so that the recommendations contained in this report can be evaluated with respect to the revised plans. The findings in this report are valid as of the date of this report. Changes in the condition of the street can occur with time. In addition, changes in the standards of practice and government regulations can occur. Thus, the findings in this report may be invalidated wholly or in part by changes beyond our control. This report should not be relied upon after a period of two years without a review by us verifying the suitability of the conclusions and recommendations to site conditions at that time. In the performance of our professional services, we comply with that level of care and skill ordinarily exercised by members of our profession currently practicing under similar conditions and in the same locality. Subsurface conditions can vary from those encountered at the boring locations, and our data, interpretations, and recommendations are based solely on the information obtained by us. We will be responsible for those data, interpretations, and recommendations, but will not be responsible for '1 ■ ■Ii -.,.., -... --- ----- ---- .. ---------------- Terramar Retail Centers La Costa Town Square Multi-Family Housing Carlsbad, California February 28, 2017 SCST No. 160518N-1 Page 7 interpretations by others of the information developed. Our services consist of professional consultation and observation only, and no warranty of any kind whatsoever, express or implied, is made or intended in connection with the work performed or to be performed by us, or by our proposal for consulting or other services, or by our furnishing of oral or written reports or findings. This opportunity to be of professional service is sincerely appreciated. Respectfully S SCST, INC. Principal Engine WLV/ER:aw Attachments: Figures Figure 1 -Site Vicinity Map Figure 2 -Geotechnical Map Appendices Appendix I -Field Investigation Appendix II -Laboratory Testing (1) Addressee via e-mail at tfitzpatrick@trcretail.com '1 ii J 17 S'11 'J ~ ~ Lacosta J lFJ \_c.t?" <:~---~. /,./ ....... ;._ n. 1 la Costa Countl)' ··-· ~vJo ._,, "_ ' .. \., :'• •• :'\• ' ,.. . . . ' ' Club I 1 \ / ', , / , ,' .. ::::,.... ,, , ... .. .,,,.. -....... -"'... ~ '~ ./ ·-,, ! ~l~l I Ii -t O" f I ll' .,-:.---: • • • ~ ' -• , I • • =~ ,t= ·1,) • • / 'I I ' J / l .. .., -~ ' '"'>,~ ', "k G ..,-V'ISti ~ .. Clfr. -..,. 'lo~ ...... ~ -~s,\ ~ ,,,. l • ~ .. --/ I , • ,. I \ .<l ""\ ... ~, 4"""¾ ,--~/# \ <J<'.,,..,,.,,. .,.....---yP>sta~ 1 I' \l" :~...,,___ i' Jl J',,/{ .... '1' . i .,p' .;,'° 51 ~~ ··~ \ j. ~~• S10 '¾, ~_,,,, J• ! .. .., ' • / ""-~ \ / . --~ • "-"' ~ ,,,. ~ ' I\ .., ¾ • ' ' . . " .... ~ . 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'\ C .lr·u=~ \\ l.= I"'-"-'.... = s~,~ ,,.... I "'""''""" \ --'\, SITE VICINITY MAP ,P~ ,.#" .<r al""' ./ ~ t .... } t -'-""' Ave:nl(S,,,P•nter• "-o,.,,,, Date: March, 2017 SCST, Inc. La Costa Town Square Multi Family Housing Carlsbad, California By: MAW Job No.: 160518N ' ' : ---~ I ,~-' : I : I ' .,\ \ ~! Figure: 1 I I I I I I I I I I I I I I ~ SCST, Inc. GEOTECHNICAL MAP La Costa Town Square Multi-Family Housing Carlsbad, California 120' 0 TP-18 Iii • • • • Jmvm SCST LEGEND: Approximate Location of Test Pit Approximate Geologic Contact Approximate Buried Geologic Contact Delmar Formation, Circled Where Buried By Compacted Fill Decomposed Metamorphic Rock, Circled Where Buried By Compacted Fill Decomposed Metamorphic Rock Metamorphic Rock, Moderately Weathered Date: March, 2017 Figure: By: MAW Job No.: 160518N 2 - ... - .. .. .. -.. .. .. -• -.. .. .. -- -.. -- - APPENDIX I FIELD EXPLORATION APPENDIX I Our field investigation consisted of logging 18 backhoe test pits to depths of between about 3 and 6 feet below the ground surface. An SCST geologist visually logged test pits. Selected samples of the exposed soil in the test pits were collected for laboratory testing. The soils are classified in accordance with the Unified Soil Classification System as illustrated on Figure 1-1, and the Caltrans Soil and Rock Logging, Classification, and Presentation Manual, 2010 Edition. Logs of the test pits are presented on Figures 1-2 through 1-19 . M ■ ■ii • • --• • -• • • -• -• -• - • • -• -- • --- .. ... • ... SUBSURFACE EXPLORATION LEGEND UNIFIED SOIL CLASSIFICATION CHART SOIL DESCRIPTION GROUP TYPICAL NAMES SYMBOL I. COARSE GRAINED, more than 50% of material is larger than No. 200 sieve size. GRAVELS CLEAN GRAVELS GW Well graded gravels, gravel-sand mixtures, little or no fines More than half of coarse fraction is GP Poorly graded gravels, gravel sand mixtures, little or no fines. larger than No. 4 sieve size but GRAVELS WITH FINES GM Silty gravels, poorly graded gravel-sand-silt mixtures. smaller than 3". (Appreciable amount of fines) GC Clayey gravels, poorly graded gravel-sand, clay mixtures . SANDS CLEAN SANDS SW Well graded sand, gravelly sands, little or no fines. More than half of coarse fraction is SP Poorly graded sands, gravelly sands, little or no fines. smaller than No . 4 sieve size. SM Silty sands, poorly graded sand and silty mixtures. SC Clayey sands, poorly graded sand and clay mixtures . II. FINE GRAINED, more than 50% of material is smaller than No. 200 sieve size. SIL TS AND CLAYS ML Inorganic silts and very fine sands, rock flour, sandy silt or clayey- (Liquid Limit less silt-sand mixtures with slight plasticity. than 50) CL Inorganic clays of low to medium plasticity, gravelly clays, sandy clays, silty clays, lean clays. OL Organic silts and organic silty clays or low plasticity . SILTS AND CLAYS MH Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, (Liquid Limit elastic silts. greater than 50) CH Inorganic clays of high plasticity, fat clays. OH Organic clays of medium to high plasticity. Ill. HIGHLY ORGANIC SOILS PT Peat and other highly organic soils. SAMPLE SYMBOLS LABORATORY TEST SYMBOLS ~ -Bulk Sample AL -Atterberg Limits CAL -Modified California sampler CON -Consolidation -CK -Undisturbed Chunk sample COR -Corrosivity Tests ----MS -Maximum Size of Particle (Resistivity, pH, Chloride, Sulfate) -ST --Shelby Tube DS -Direct Shear SPT -Standard Penetration Test sampler El -Expansion Index ~ MAX -Maximum Density GROUNDWATER SYMBOLS RV -R-Value ? -Water level at time of excavation or as indicated SA -Sieve Analysis UC -Unconfined Compression 3~ -Water seepage at time of excavation or as indicated RW -Response to Wetting II ■ LA COSTA TOWN SQUARE MULTI-FAMILY HOUSING SCST, Inc. Carlsbad, California ■ii By: WLV !Date: February, 2017 Job Number: 160518N I Figure: 1-1 --- LOG OF TEST PIT TP-1 - Date Drilled: 12/7/2016 Logged by: WLV -Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered - SAMPLES l 13 (/) .8, I-I-(/) z I-w g w J: I-I-(!) ~ (/) z iu :c 0 z 0 Ii: SUMMARY OF SUBSURFACE CONDITIONS w ~ 0 ?i: 0 (/) ...I ::::, > ::::, w I-~ w a: C m a: z C ::::, I-:::> 0 rn >-co 5 a::: :5 :i: Q --.. -- GC FILL (Qf) -CLAYEY GRAVEL with SAND, moderate brown, moist, low plasticity . -.... - .... 1 -------------------------------------------GP POORLY GRADED GRAVEL with SAND, gray, moist. ---------------------------------------------GC CLAYEY GRAVEL, moderate brown, moist, low plasticity. .... 2 --- -3 -------------------------------------------CL LEAN SANDY CLAY, greenish gray, moist, medium plasticity. X El, COR - .... 4 TD4FEET -- .. ---5 ---- 6 -.... --7 ---- 8 ---- 9 ----10 - '1 ■ La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-2 ----• .. • • -• .. • - - • .. - - - -.. - - -.. LOG OF TEST PIT TP-2 Date Drilled: 12/7/2016 Logged by: WLV Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered SAMPLES ~ 'a ~ en ~ .9: I-I-en z I-w g w J: I-I-C) ~ en z w I 0 SUMMARY OF SUBSURFACE CONDITIONS z 0 I-en w ~ 0 3;: 0 0. > ..J ~ w :::) ~ :::) w I-0 co ~ z 0 :::) I-::::> 0 en > ID 5 0:: ~ ::E 0 GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. - -1 - - 2 ---------------------------------------------CH GRAVELY FAT CLAY grayish green, moist, high plasticity. ----------------------------------------------GM SIL TY GRAVEL with SAND, moderate brown, moist. - 3 - - 4 - - 5 TD 5 FEET - - 6 - - 7 - -8 - ..... 9 ..... -10 11 ■1 La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California UJ ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-3 Date Drilled: 12/7/2016 Equipment: Backhoe LOG OF TEST PIT TP-3 Logged by: WLV Project Manager: DS Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered SAMPLES ~ 'fi' ~ .9, I-z I-w :I: g I-(!) (/) z iii J: () SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 li: (/) w () s: > ...I w :::> [( :::> w I- C m 0:: z C :::> I-:::> (/) ~ 0 ~ 0 CH FILL (Qf) -GRAVELY CLAY, greenish gray, moist, high plasticity. - - 1 ----------------------------------------------GC SILTY to CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. - 2 - 3 - en ~ w I- ~ 0 i 0 al ::S -4~•--------------------------~-~-~-~-~~~ TD 5 FEET - 5 - .... 6 .... .... 7 .... ,_ - 9 - -10'--'-----------------------------L---L----'----''----JL-----l SCST, Inc. By: Job Number: La Costa Town Square Multi-Family Housing Carlsbad, California MAN Date: February, 2017 160518N Figure: 1-4 ----------- ------- • -- -----------• -- -• -• • -• -- • -• - - • • --.. • .. .. .. .. LOG OF TEST PIT TP-4 Date Drilled: 12/7/2016 Logged by: WLV Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered SAMPLES -'a :R. (/) e.., .9, I-I-(/) z I-w g w :::c I-I-(!) >-en z w J: 0 z 0 ~ I-SUMMARY OF SUBSURFACE CONDITIONS w ~ 0 :!: 0 a. en > ..J ~ w :::, ~ :::, w I-0 Ill a:: z 0 :::, I-::> 0 en >-al 0 ~ ~ :E C GM FILL (Qf) -SIL TY GRA VEL,moderate brown, moist, little fine-grained SAND, medium .... plasticity . .... 1 CH DELMAR FORMATION (Td}-FAT CLAY, greenish gray, moist, high plasticity, .... moderately indurated. - 2 .... - 3 - .... 4 TD4 FEET - -5 - - 6 - - 7 - - 8 - - 9 - -10 11 ■! La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-5 --- LOG OF TEST PIT TP-5 ... Date Drilled: 12/7/2016 Logged by: WLV -Equipment: Backhoe Project Manager: DS Elevation (ft}: Approximately 292 Groundwater Depth (ft): Not Encountered - SAMPLES l '5' (/) a I-I-(/) z I-w g w :::c: I-I-C!) ~ en z jjj J: 0 z ~ 0 I-SUMMARY OF SUBSURFACE CONDITIONS w 0 ~ 0 Q.. en > ...J ~ w :::, ii: :::, w I-0 Ill a:: z 0 :::, I-:::> 0 ---- en >-al 0 er: ~ ~ C - GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. -- -1 CH DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity, - ..... fissured, moderately indurated. - ..... 2 --- ..... 3 --..... - 4 TD4FEET ---- 5 -..... ... ..... 6 -..... -..... 7 -..... ""' ..... 8 -..... .. ..... 9 -..... --10 - 11 ■1 La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-6 --• -- -.. • --• -• --• -• -• --- -• -- .. ... - - .. .. -.. LOG OF TEST PIT TP-6 Date Drilled: 12/7/2016 Logged by: WLV Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered SAMPLES ~ 'fi' ~ (/) ~ .9: I-I-(/) z I-w g w :::c: I-I-(!) ~ (/) z iii ::c: 0 SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 I-(/) w 0 s: 0 a. > ..J i w ::) ii: ::) w I- 0 ID a: z 0 ::) I-:::> 0 (/) >-(0 0 a:: :5 ~ 0 GM FILL (Qfl-SILTY GRAVEL with SAND, moderate brown, moist, non-plastic. ,- -1 - ,-2 - -3 CH DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity. - - 4 -TD4¼FEET - 5 - -6 ,- ,-7 ,- ,-8 --9 - -10 JI ■ La Costa Town Square Multi-Family Housing SCST, Inc . Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-7 --- LOG OF TEST PIT TP-7 - Date Drilled: 12/7/2016 Logged by: WLV -Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered - SAMPLES -'fi' ~ (/) .8, I-I-(/) z I-w §: w :c I-I-(!) >-en z iii :c (.) SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 0::: I-en w (.) s:: 0 a. > ....I ~ w ::, ii: ::, w I- 0 III 0:: z 0 ::, I-:::, 0 --- en >-ID 5 0::: ::s :E C - CL DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity. --.. -1 -- -2 --- -3 ---TD3¼ FEET .. -4 ---- 5 ----6 ----7 ----8 --- -9 ----10 - II ■ La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-8 ----- -• .. -• -• -• -• .. -• ---• -- .. - - .... .. LOG OF TEST PIT TP-8 Date Drilled: 12/7/2016 Logged by: MAN Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 291 Groundwater Depth (ft): Not Encountered SAMPLES -'5' ~ en .9:: I-I-en z I-w g w ::c I-I-(!) ~ (/) z w ::i::: 0 SUMMARY OF SUBSURFACE CONDITIONS z :::;:: 0 I-(/) w 0 3: 0 a. > ...I ~ w => i:2 => w I-0 m a:: z 0 => I-::> 0 (/) ~ co 5 ~ ::i: 0 GC FILL (Qfl-CLAYEY GRAVEL with SAND, moderate brown, moist, medium plasticity. - ..... 1 ..... ..... 2 CH DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity. - ..... 3 - ..... 4 TD4FEET - ..... 5 - ..... 6 --7 ..... ..... 8 - - 9 ..... ..... 10 51 ■1 La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-9 --- LOG OF TEST PIT TP-9 - Date Drilled: 12/7/2016 Logged by: MAN -Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 291 Groundwater Depth (ft): Not Encountered - SAMPLES ~ 'a en ~ .e, I-I-en z I-w g w ::c I-I-C!) ~ en z jjj J: (.) SUMMARY OF SUBSURFACE CONDITIONS z ::.::: 0 I-en w (.) 3: 0 a. > ..J i w ::, a: ::, w I- Q al a::: z Q ::, I-:::> 0 ... - - en ~ co 0 ~ ::i: C - GC FILL (Qfl -CLAYEY GRAVEL with SAND, green and orange, moist, medium - ..... plasticity . - ..... 1 - ---CH DELMAR FORMATION (Td) -FAT CLAY, moderate brown, moist, high plasticity. X I-2 El, COR ..... ----3 TD 3 FEET -I- -4 -..... --5 -I-.. -6 -,--,-7 111111 ,--,_ 8 -,--,-9 -,-- ~ 10 11111 '1 ■j La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-10 ----- • • -• --.. • -.. --• - - • -- ---.. • .. .. ... ... .. LOG OF TEST PIT TP-10 Date Drilled: 12/7/2016 Logged by: MAN Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered SAMPLES -'a ::Ji!. (/) ~ .9: I-I-(/) z I-w g w :c I-I-(!) ~ en z w ::i::: (.) SUMMARY OF SUBSURFACE CONDITIONS z ::,::: 0 I-en w (.) 3: 0 a. > ...I i w ::::, " ::::, w I-0 Ul a:: z 0 ::::, I-::::, 0 en ~ en 5 ~ :E Cl CH DELMAR FORMATION (Tdl-FAT CLAY, moderate brown and greenish gray, moist, I-high plasticity, poorly indurated. -1 .... .... 2 METAMORPHIC ROCK (Jmv): Intensely weathered rock, light brown, non-plastic .... - 3 .... - 4 .... TD4¼ FEET - 5 .... ,-6 .... .... 7 .... ,-8 I- .... 9 ,- -10 11 ■1 La Costa Town Square Multi-Family Housing SCST, Inc . Carlsbad, California ■Di By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-11 ---LOG OF TEST PIT TP-11 -Date Drilled: 12/7/2016 Logged by: MAN -Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered - SAMPLES -'ti' ~ Cl) .e, I-I-Cl) z I-w g ~ ::c I-(!) ~ "' z w :c (.) SUMMARY OF SUBSURFACE CONDITIONS z ::ii:: 0 t "' w (.) :;: 0 ::> > ...J ~ w ii: ::> w I- 0 m a: z 0 ::> I-:::> 0 ... .. -- "' >-ID 0 0:: ~ :::iE C ... CH DELMAR FORMATION {Tdl -FAT CLAY, greenish gray, moist, high plasticity, poorly - indurated. ---1 - -- -2 --- - 3 -----4 ... -TD4¼ FEET ... -5 --.: ,-6 -,--..... 7 -,--,-8 ---..... 9 -..... --10 ~-i La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■Di By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-12 ----- -• -- • -• -• -----• • • -• .. • ------- .. -.. - LOG OF TEST PIT TP-12 Date Drilled: 12/7/2016 Equipment: Backhoe Logged by: MAN Project Manager: DS Elevation (ft): Approximately 293 Groundwater Depth (ft): Not Encountered g :c I-a. w 0 --1 - - 2 - - 3 - - 4 - - 5 - -6 ,- ,-7 ,- ,-8 ,- ,-9 - -10 en 0 SUMMARY OF SUBSURFACE CONDITIONS en :) CH FILL (Qf) -FAT CLAY with SAND, medium brown, moist, high plasticity. CH DELMAR FORMATION (Td)-FAT CLAY, greenish gray, moist, high plasticity, poorly indurated. TD6 FEET SAMPLES z ~ w > ..J a: :) Cll 0 -13' ~ ~ ,9, I-z I-w :I: I-C!) z jjj 0 0 3: w I-0::: z :) I-:::) en ~ 5 ::i: 0 La Costa Town Square Multi-Family Housing Carlsbad, California (/) I-(/) w I- >-0:: 0 ~ 0 al ~ SCST, Inc. By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-13 LOG OF TEST PIT TP-13 Date Drilled: 12/7/2016 Logged by: MAN Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 292 Groundwater Depth (ft): Not Encountered SAMPLES ~ 'fi' :,E! (/) e.... E; I-I-(/) z I-w g w ::c I-I-(!) ~ en z w ::c 0 SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 I-en w 0 ~ 0 a. > ..J ~ w :::> a:: :::> w I-0 ID 0::: z 0 :::> I-:::> 0 en >-00 0 0:: ::s ::i: Cl CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity, poorly indurated. - -1 - - 2 - -3 ..... --4 TD4FEET -- -5 - ..... 6 - ..... 7 ..... --8 -- --9 ..... -10 ll ■l La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■Di By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-14 ---------- --- ---- ------ ----------- • • -.. --• -- -• -• LOG OF TEST PIT TP-14 -Date Drilled: 12/7/2016 Logged by: MAN • Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered • --• - SAMPLES ~ 'n en ~ .9: I-I-en z I-LU g w J: I-I-(!) ft: Cl) z jjj ::c: 0 SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 Ii: Cl) w 0 3: 0 :) > ..J ~ w ii: :) w I- C m 0::: z C :) I-:::, 0 Cl) >-en 5 0::: :5 :::!!; 0 -CH METAMORPHIC ROCK (Jmv) -light brown, decomposed rock. -.... -.... 1 -,- • .... 2 -,- • ,-3 -.... -.... 4 -,- • ,-5 -.... • TD 5½ FEET .... 6 .. .... -,-7 -.... .... 8 -,- ,--9 -.... ... , .... 10 .. .. '1 ■i La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California UI ■iii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-15 - ---LOG OF TEST PIT TP-15 -Date Drilled: 12/7/2016 Logged by: MAN -Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 294 Groundwater Depth (ft): Not Encountered - SAMPLES ~ 'u" Cl) ~ .s, I-I-Cl) z I-w §: w J: I-I-(!) ~ en z w ::i::: 0 SUMMARY OF SUBSURFACE CONDITIONS z ~ 0 I-en w 0 ~ 0 0.. ::, > ..J i w 0:: ::, w I-Cl ID a:: z Cl ::, I-::, 0 -.. --en ~ al 0 ~ ::i: C - GC FILL (Qfl -CLAYEY GRAVEL with SAND, moderate brown, moist, low plasticity. ----1 - --CH DELMAR FORMATION {Td) -FAT CLAY with SAND, greenish gray, moist, high X - 2 plasticity, poorly indurated. El, COR - -- - 3 .___ --- • - 4 ---- 5 --TD 5½ FEET -,-6 -,--..... 7 .. ,--..... 8 -..... ..... 9 -,- -10 - It ■ La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-16 ----- • • -• -- • .. • -• - -• -• -• -------.. -- ---.. LOG OF TEST PIT TP-16 Date Drilled: 12/7/2016 Logged by: MAN Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 295 Groundwater Depth (ft): Not Encountered SAMPLES -'fi' ::.E! Cl) e.... .9, I-I-Cl) z I-w g w J: I-I-(!) ~ en z iii :I: u z 0 I-en SUMMARY OF SUBSURFACE CONDITIONS w ~ u s: 0 Q. > ...J ~ w ::, ~ ::, w I-0 ID er:: z 0 ::, I-::, 0 en >-al 5 a::: :s ::i: □ CH FILL (Qf) -FAT CLAY with SAND, brown and greenish gray, moist, low to medium -plasticity. -1 - -El, -2 COR - -3 - - -4 - -5 TD 5 FEET - -6 - -7 - -8 - -9 - -10 '1 ■ La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■Ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-17 ---LOG OF TEST PIT TP-17 -Date Drilled: 12/7/2016 Logged by: MAN -Equipment: Backhoe Project Manager: DS Elevation (ft): Approximately 296 Groundwater Depth (ft): Not Encountered .. SAMPLES ~ '5' (/) ~ s I-I-(/) z I-w g w :::c: I-I-(!) ~ (/) z w :c 0 SUMMARY OF SUBSURFACE CONDITIONS z 0 I-w ~ 0 ~ 0 (/) ...I a. ::> > ::> w ~ w 1i:: I- 0 ID a: z 0 ::> I-:::> 0 ----(/) >-co 0 er:: ~ :::!: 0 - GP FILL (Qf) -POORLY-GRADED GRAVEL with SAND, moderate brown, moist, non-- -plastic. - ,-1 --~ METAMORPHIC ROCK (Jmvl -light brown, intensely weathered rock. ,-2 El, COR ,.... --- - 3 ----- 4 ---- 5 -,--,.... 6 TD 6 FEET -,.... ,-7 -,- ,.... 8 -- -9 -,---10 - '1 ■ La Costa Town Square Multi-Family Housing SCST, Inc. Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-18 --• -- .. • LOG OF TEST PIT TP-18 Date Drilled: 12/7/2016 Logged by: MAN • Equipment: Backhoe Project Manager: OS Elevation (ft): Approximately 296 Groundwater Depth (ft): Not Encountered • • SAMPLES l 'a Cl) .e, I-I-Cl) z I-w §: w :r: I-I-(!) ~ en z iii :I: 0 SUMMARY OF SUBSURFACE CONDITIONS z ::.:: 0 I-en w 0 3:: 0 Q. ::) > ...J i w a: ::) w I- 0 rn a: z 0 ::) I-::::, 0 en ~ al 0 :5 ~ D CH DELMAR FORMATION (Td) -FAT CLAY, greenish gray, moist, high plasticity. ---1 -• - 2 -- - 3 .. - - 4 TD4FEET --.. - 5 .. ---6 ----7 --.. -8 --.. -9 ----10 .. .. .. II ■ La Costa Town Square Multi-Family Housing SCST, Inc . Carlsbad, California ■ii By: MAN Date: February, 2017 Job Number: 160518N Figure: 1-19 - .. .. • .. - - --- -... • .. .. -- .. 1111 .. - - • APPENDIX II LABORATORY TESTING SUMMARY APPENDIX II Laboratory tests were performed to provide geotechnical parameters for engineering analyses. The following tests were conducted: • EXPANSION INDEX: The expansion index of three samples was determined in accordance with ASTM D4829. Figure 11-1 presents the test results. • CORROSIVITY: Corrosivity tests were performed on five samples. The pH and minimum resistivity were determined in general accordance with California Test 643. The soluble sulfate content was determined in accordance with California Test 417. The total chloride ion content was determined in accordance with California Test 422. Figure 11-1 presents the test results. 4111 .. • -• - ' --• .a .. • -• • .. -.. .. .. .. • - .. .. EXPANSION INDEX ASTM 02489 SAMPLE DESCRIPTION EXPANSION INDEX TP-1 FILL: LEAN SANDY CLAY, greenish gray 51 TP-9 DELMAR FORMATION: FAT CLAY, moderate brown 104 TP-15 DELMAR FORMATION: FAT CLAY, greenish gray 108 TP-16 FILL: FAT SANDY CLAY, greenish gray 116 TP-17 METAMORPHIC ROCK SANDY CLAY, light brown, decomposed 110 CLASS/FICA TION OF EXPANSIVE SOIL 1 EXPANSION INDEX POTENTIAL EXPANSION 1 -20 Very Low 21 -50 Low 51 -90 Medium 91 -130 High Above 130 Very High 1. ASTM -D4829 RESISTIVITY, pH, SOLUBLE CHLORIDE and SOLUBLE SULFATE SAMPLE RESISTIVITY (0-cm) pH CHLORIDE (%) SULFATE(%) TP-1 288 7.28 0.066 0.171 TP-9 189 6.09 0.022 0.141 TP-15 149 7.27 0.049 0.144 TP-16 290 6.9 0.006 0.020 TP-17 179 6.82 0.001 0.016 SULFATE EXPOSURE CLASSES2 Class Severity Water-Soluble Sulfate (SO4) in Soll, Percent by Mass so Not applicable SO4 < 0.10 S1 Moderate 0.10 s SO4 < 0.20 S2 Severe 0.20 s SO4 s 2.00 S3 Very Severe SO4 > 2.00 2. ACI 318, Table 4.2.1 ~ ■ SCST, INC. La Costa Town Square Multi-Family Housing Carlsbad, California ■ii By: WLV Date: February, 2017 Job Number: 160518N Figure: 11-1