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CT 2018-0001; WALNUT BEACH HOMES; STORM WATER QUALITY MANAGEMENT PLAN; 2018-05-01
---... -.. -.. ---... ---... -... -.. .. , .. .. ... -.. -----.. --... .. -- CITY OF CARLSBAD PRIORITY DEVELOPMENT PROJECT (PDP) STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) FOR WALNUT BEACH HOMES 362 WALNUT AVENUE CT 2018-0001 / CDP 2018-0003 / PUD 2018-0001 q DWG ENGINEER OF WORK: ~ TYLER G LAWSON, PE #80356 PREPARED FOR: RINCON REAL ESTATE GROUP 3005 S. EL CAMINO REAL SAN CLEMENTE, CA 92672 PH: (949) 438-5494 PREPARED BY: PASCO, LARET, SUITER & ASSOCIATES 535 N. HWY 101, SUITE A SOLANA BEACH, CA 92075 PH: (858) 259-8212 DATE: JANUARY 2018 REVISED: MARCH 2018 REVISED: MAY 2018 R '"'.: f"'_ rn • · · . -, ..__,.._.7.·...,j\ . ..J MAY 1 7 2018 C'lTY : ,,· (_, •·. FL· .. ::-li:\JG __)_, ... ... - .. TABLE OF CONTENTS -.. -.. ... ... ... Ir ... -.. ------... .. --... .. -.. --.. -• -.. ... .. 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 1a: OMA Exhibit Attachment 1 b: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment 1c: Harvest and Use Feasibility Screening (when applicable) Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable) Attachment 1 e: 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: SWMM Model Output and Support Documentation ---.. ,.. -.. ------.. -------- CERTIFICATION PAGE Project Name: Walnut Beach Homes Project ID: CT 2018-0001 / CDP 2018-0003 / PUD 2018-0001 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. Engineer Tyler Lawson Print Name /2-J/-1'1 ark's Signature, PE Number & Expiration Date Pasco Lare! Suiter & Associates • Company --Date ------------ ----PROJECT VICINITY MAP ----.. \ .. .. --.. ---.. --VICINITY MAP -I/OTTO SCALE -----.. --.. ---... ... •• -- -... .. .. • -- -.. ---.. ----,. -----------.. .. .. ---.. - [Insert City's Storm Water Standard Questionnaire (Form E-34) here] C cityof Carlsbad STORM WATER STANDARDS QUESTIONNAIRE Development Services Land Development Engineering 1635 Faraday Avenue {760) 602-2750 www.carlsbadca.gov E-34 I INSTRUCTIONS: 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: Walnut Be.ach Homes PROJECT ID: CT 2018-000 I / CDP 2018-000 ADDRESS: 362 Walnut Avenue APN: 204-1 32-17-00 The project is (check one): D New Development !XI Redevelopment The total proposed disturbed area is: 25 ,020 ft2 ( 0.574 ) acres The total proposed newly created and/or replaced impervious area is: 11 ,286 ft2 ( 0.26 ) 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 NIA SWQMP#: NIA 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 3 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)? • [ZI 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; • IX] 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 auidance? 2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in • IX] 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? • IX] 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, vour oroiect is not exempt from PDP, go to Step 3. E-34 Page 2 of 4 REV 04/17 To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(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, and ublic develo ment ro ·ects on ublic or rivate land. 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 more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public develo ment ro ·ects on ublic or rivate land. 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 refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification SIC code 5812 . 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 develo ment ro·ect includes develo ment on an natural slo e that is twent -five ercent or reater. 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 a land area or facility for the temporary parking or storage of motor vehicles used personally for business or for commerce. 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 site? A street, road, highway, freeway or driveway is any paved impervious surface used for the trans ortation of automobiles, trucks, motorc cles, and other vehicles. 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 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 ro ·ect to the ESA i.e. not commin led with flows from ad·acent lands . * 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 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. 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 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 er da . 1 O. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land 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 21.203.040 YES NO • IX] • • IX] • [XI • • • • IX] • IX] • • IX] If you answered "yes" to one or more of the above questions, your project is a POP. 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 POP ... " 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 statin "M ro·ect is a 'STANDARD PROJECT' ... " and com lete a licant information. E-34 Page 3 of 4 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 50% of the surface area of the previously existing development? Complete the percent impervious calculation below: Existing impervious area (A) = 3,742 sq. ft. IX] • Total proposed newly created or replaced impervious area (B) = 11 ,286 sq . ft. Percent impervious area created or replaced (B/A)*100 = 302 % 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 BMP's required for PDP apply to the entire development. Go to step 5, check the check the first box statina "Mv oroiect is a PDP ... " and complete applicant information. STEP5 CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION IX] 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. 0 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: KevinDynn ,A ~ Applicant Title: Manager Applicant Signature: 'h VJ Date: '7 ,-1 10 . ( I I • Environmentally Sensitive Areas includei~re not limited to all Clean Water Act Section 303(d) impai ed wat ~r bodies; areas designated as Areas of Special Biolo ical Si nificance b the State Water esources Control Board Water Qualit Control Plan for the 1 an Die o Basin (1994) and amendments); water bodies g g y ( y g designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; Habitat Management Plan; and any other equivalent environmentally sensitive areas which have been identified by the City. This Box for Citv Use Onlv YES NO City Concurrence: • • By: Date: Project ID: E-34 Page 4 of 4 REV 04/17 SITE INFORMATION CHECKLIST Prolect Summarv lnfonnatlon Project Name Walnut Beach Homes Project ID CT 2018-0001 / CDP 2018-0003 I PUD 2018-0001 Project Address 362 Walnut Avenue Carlsbad, CA 920 Assessor's Parcel Number(s) (APN(s)) 204-132-17-00 Project Watershed (Hydrologic Unit) Carlsbad 904.21 (Agua Hedionda HSA) Parcel Area 0.574 Acres ( 25,020 Sauare Feet) Existing Impervious Area (subset of Parcel Area) 0.086 Acres ( 3.762 Square Feet) Area to be disturbed by the project 0.574 Acres ( 25,020 (Proiect Area) Square Feet) Project Proposed Impervious Area (subset of Proiect Area) 0.259 Acres ( 11 ,286 Square Feet) Project Proposed Pervious Area (subset of Proiect Area) 0.315 Acres ( 13,734 Square Feet) Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project. This mav be less than the Parcel Area. Descrlotlon of Exlstlna Site Condition and Dralnaae Patterns Current Status of the Site (select all that apply): ✓ Existing development D Previously graded but not built out • Agricultural or other non-impervious use o Vacant, undeveloped/natural Description / Additional Information: Existing Land Cover Includes (select all that apply): ✓ Vegetative Cover ✓ Non-Vegetated Pervious Areas ✓ Impervious Areas Description / Additional Information : Underlying Soil belongs to Hydrologic Soil Group (select all that apply): D NRCS Type A ✓ NRCS Type B D NRCS Type C D NRCS Type D Approximate Depth to Groundwater (GW): D GW Depth < 5 feet D 5 feet < GW Depth < 10 feet D 10 feet < GW Depth < 20 feet ✓ GW Depth > 20 feet Existing Natural Hydrologic Features (select all that apply): D Watercourses • Seeps D Springs •Wetlands ✓ 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]: (1) Existing drainage conveyance can be categorized as urban. However, there does not appear to be any significant drainage infrastructure onsite to convey storm water, and water travels through the site on the surface by way of sheet flow. Water eventually leaves the site to the southwest towards Walnut Avenue, flowing on the surface and entering the public right-of- way. (2) There do not appear to be any existing onsite storm water conveyance systems. Water eventually leaves the subject property at the southwest corner of the site toward Walnut Avenue. Public storm drain infrastructure in Walnut Avenue then intercepts runoff and routes east to the NCTD railroad right-of-way, discharging through a headwall and rip rap once through Washington Street. It should be noted that based on a study by Pasco, Laret, Suiter & Associates of the local drainage basin draining to Walnut Avenue, the existing storm drain is at or very near capacity in the current condition. There appears to be a storm drain system located in the NCTD railroad right-of-way that eventually intercepts runoff and routes it south towards the Agua Hedionda Lagoon. (3) Offsite runoff is not conveyed through the project site. Existing residential developments surrounding the property, in addition to Walnut Avenue to the south, preclude drainage from entering the site by way of neighboring properties. Description of Pro:: · Site DeveloDment and Dralnaae Patterns Project Description / Proposed Land Use and/or Activities: The project proposes to demolish all existing onsite structures, clear and grub the site, and construct 11 new multi-family condominium units along with a shared driveway and walkways. List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): Proposed impervious features onsite include buildings and concrete walkways List/describe proposed pervious features of the project (e.g., landscape areas): Proposed pervious features onsite include landscaping, a treatment control BMP basin, and a driveway consisting of large concrete pads with gravel-filled openings to promote infiltration Does the project include grading and changes to site topography? ✓ Yes •No Description/ Additional Information: Project proposes to precise the grade the site along with some changes to onsite topography. The onsite grading consists of 675 CY of cut and 125 CY of fill, resulting in 550 CY of export. The site has been designed to drain to a HMP-sized bioretention basin and a low point near the northern portion of the lot. Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)? ✓ Yes •No Description/ Additional Information: 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 D Interior parking garages D Need for future indoor & structural pest control ✓Landscape/Outdoor Pesticide Use D Pools, spas, ponds, decorative fountains, and other water features D Food service D Refuse areas D Industrial processes o Outdoor storage of equipment or materials D Vehicle and Equipment Cleaning D Vehicle/Equipment Repair and Maintenance D Fuel Dispensing Areas D Loading Docks D Fire Sprinkler Test Water o Miscellaneous Drain or Wash Water D Plazas, sidewalks, and parking lots Identification of Recelvlna 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): 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 Agua Hedionda Lagoon Enterococcus Fecal Coliform Manganese Phosphorus Selenium Total Dissolved Solids Identification of Prolect Site Pollutants Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix 8.6): Also a Receiving Not Applicable to Anticipated from the Water Pollutant of Pollutant the Proiect Site Proiect Site Concern Sediment X Nutrients X Heavv Metals Oraanic Comoounds Trash & Debris X Oxygen Demanding Substances X Oil & Grease X Bacteria & Viruses X Pesticides X Hydromodlflcatlon Manaaement Reaulrements Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? ✓ Yes, hydromodification management flow control structural BMPs required. D 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. D 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 onlv reaulred If hvdromodlflcatlon manaaement reaulrements annlv Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? •Yes ✓ No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? D 6.2.1 Verification of Geomorphic Landscape Units (GLUs) 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 D 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? D No critical coarse sediment yield areas to be protected based on verification of GLUs onsite D 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: Flow Control for Post-Project Runoff" "This Section onlv reaulred If hvdromodlflcatlon manaaement reaulrements &DDlv 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. The point of compliance (POC-1) for this project is the location at which drainage leaves the subject property. Refer to the HMP Exhibit included in Attachment 2 of this report and the following page for a discussion of the project POC. Has a geomorphic assessment been performed for the receiving channel(s)? ✓ No, the low flow threshold is 0.1O2 (default low flow threshold) D Yes, the result is the low flow threshold is 0.102 D Yes, the result is the low flow threshold is 0.3O2 • Yes, the result is the low flow threshold is 0.5O2 If a geomorphic assessment has been performed, provide title , date, and preparer: NIA Discussion / Additional Information: (optional) Other Site Reaulrements 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. NIA ODtlonal Additional lnfonnatlon or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed. Continued from "Flow Control for Post-Project Runoff': This project proposes a micro-diversion of runoff within the Agua Hedionda Hydrologic Sub- Area of the Carlsbad watershed. Flows leaving the subject property in the existing condition currently appear to enter Walnut Avenue infrastructure from the southwest corner of the property before discharging east to NCTD right-of-way. From there, runoff is conveyed south to the Agua Hedionda Lagoon. In the proposed condition, storm water is collected and routed to the northeast corner of the property for treatment and detention before outletting in the Washington Street right-of-way. Once in Washington Street, existing curb and gutter route flows north for a City block before also discharging east to NCTD right-of-way. These micro- diverted flows are then conveyed south in the same storm drain system as in the existing condition to outlet in the Agua Hedionda Lagoon. For storm water modeling purposes using SWMM, the point of compliance for the project is assumed to be the point that storm water discharges from the property in the existing and proposed condition. However, to demonstrate compliance with the regional MS4 Permit, the ultimate point of compliance occurs in NCTD right-of-way downstream to the southeast of the subject property. Refer to Attachment 2 of this report for the project's HMP Exhibit and offsite point of compliance. The micro-diversion of flows occurs for only a short period before ultimately entering the same storm drain system and reaching the outlet in the Agua Hedionda Lagoon. The micro-diversion also helps alleviate an already sub-standard drainage condition by directing water away from the storm drain system in Walnut Avenue that is currently at capacity. Additional options were studied on where to ultimately discharge from the subject property, and the proposed solution was deemed the most practical and feasible. Continued from "Proposed Site Development and Drainage Patterns" The panhandle portion of the existing parcel is self-mitigating in the proposed condition. The project proposes to replace existing AC pavement with a concrete drive with gravel-filled openings that will behave like a pervious material and provide LID treatment along with water quality benefits. [Insert City's Standard Project Requirement Checklist Form E-36 (here)] C cityof Carlsbad STANDARD PROJECT REQUIREMENT CHECKLIST E-36 Project lnfonnatlon Project Name: Walnut Beach Homes -362 Walnut Avenue Project ID: CT 2018-00011 CDP 2018-00031 PUD 2018-0001 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. • "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion/justification may be provided. Source Control Requirement Applled? SC-1 Prevention of Illicit Discharges into the MS4 ~Yes D No 0 N/A Discussion/justification if SC-1 not implemented: SC-2 Storm Drain Stenciling or Signage ~Yes D No 0 N/A Discussion/justification if SC-2 not implemented: No public storm drain inlets proposed for stenciling and/or signage; provide signage for private storm drain as needed and adjacent to BMP basin SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind •Yes D No ~ N/A Dispersal Discussion/justification if SC-3 not implemented: No permanent outdoor materials storage areas proposed by this project E-36 Page 1 of 4 Revised 09/16 Source Control Reaulrement (continued) ADDlled? 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: No permanent materials stored in outdoor work areas proposed by this project 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: All outdoor trash storage areas will be covered to protect from rainfall, run-on, and wind dispersal 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 auidance). Iii On-site storm drain inlets Iii Yes D No 0 N/A • Interior floor drains and elevator shaft sump pumps • Yes 0 No Iii N/A • Interior parking garages •Yes D No Iii N/A • Need for future indoor & structural pest control D Yes D No Iii NIA Iii Landscape/Outdoor Pesticide Use Iii Yes 0 No 0 N/A D Pools, spas, ponds, decorative fountains, and other water features D Yes D No Iii NIA • Food service D Yes D No Iii N/A D Refuse areas D Yes D No Iii N/A D Industrial processes •Yes 0 No Iii N/A • Outdoor storage of equipment or materials •Yes 0 No Iii NIA • Vehicle and Equipment Cleaning D Yes D No Iii N/A • Vehicle/Equipment Repair and Maintenance D Yes D No Iii NIA • Fuel Dispensing Areas D Yes D No Iii N/A D Loading Docks • Yes 0 No Iii NIA • Fire Sprinkler Test Water •Yes 0 No Iii N/A • Miscellaneous Drain or Wash Water D Yes 0 No Iii N/A • Plazas, sidewalks, and oarkina lots •Yes 0 No Iii N/A For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers. Only private area drains proposed for on-site storm drain inlets. No operational BMP's proposed. Landscaping will be maintained using minimum or no pesticides E-36 Page 2 of 4 Revised 09/16 Site DNlgn BMPa 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 DNlgn Requirement I Applled? SD-1 Maintain Natural DrainaQe Pathways and HvdroloQic Features I • Yes I • No I lj] NIA Discussion/justification if SD-1 not implemented: No natural drainage pathways/ hydrologic features to maintain SD-2 Conserve Natural Areas, Soils, and Vegetation l • Yes I lj] No I • NIA Discussion/justification if SD-2 not implemented: Entire project site is proposed to be graded to accommodate the proposed site plan SD-3 Minimize Impervious Area I lj] Yes I • No I • NIA Discussion/justification if SD-3 not implemented: SD-4 Minimize Soil Compaction I !j] Yes I • No I • N/A Discussion/justification if SD-4 not implemented: Soil compaction outside of building envelopes will be minimized . Project drive aisle proposes segmental PCC slabs with gravel-filled openings to promote infiltration. Soil compaction under PCC pavers is proposed to increase conductivity. SD-5 Impervious Area Dispersion I lj] Yes I • No I • NIA Discussion/justification if SD-5 not implemented: Segmental PCC slabs with gravel-filled openings proposed for drive aisle. E-36 Page 3 of 4 Revised 09/16 Site Design Requirement (continued) l ADDlled? 50-6 Runoff Collection I [i] Yes ] D No I D N/A Discussion/justification if SD-6 not implemented: 50-7 Landscaping with Native or Drought Tolerant Species l [i] Yes I D No I D NIA Discussion/justification if SD-7 not implemented: 5D-8 Harvesting and Using Precipitation l • Yes l D No I [i] NIA Discussion/justification if SD-8 not implemented: No harvest and reuse proposed with this project E-36 Page 4 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. Based on the initial development of the project site plan, the location of the storm water pollutant BMP was chosen towards the northern property line to accommodate the proposed drainage design. Once the results of onsite infiltration testing were acquired in the area proposed for the basin, it was determined that partial infiltration of the DCV was feasible for this project site. The onsite drainage basin discharging to the project BMP was delineated, the DCV was then calculated, and the BMP was sized to comply with hydromodification and storm water pollutant control requirements of the MS4 Permit using the EPA Storm Water Management Model (SWMM) software to conduct the analysis. Refer to Attachment 5 of this report for results from the analysis. A structural BMP is not proposed to treat the panhandle portion of the existing parcel , as this area is self-mitigating. The project proposes to replace existing AC pavement with a concrete drive with gravel-filled openings that will behave like a pervious material and provide LID treatment along with water quality benefits. [Continue on next page as necessary.] Structural BMP Summary lnfonnatlon [Copy this page as needed to provide lnfonnatlon for each Individual proposed structural BMPl Structural BMP ID No. BMP-1 DWG CT 2018-0001 / CDP 2018-0003 Sheet No. 2-4 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) ✓ Partial retention by biofiltration with partial retention (PR-1) D 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) • Detention pond or vault for hydromodification management • Other (describe in discussion section below) Purpose: D Pollutant control only D Hydromodification control only ✓ Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 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: Attachment Contents Checklist Sequence Attachment 1 a OMA Exhibit (Required) Attachment 1 b Attachment 1 c Attachment 1 d Attachment 1 e See OMA Exhibit Checklist on the back of this Attachment cover sheet. (24"x36" Exhibit typically required) Tabular Summary of DMAs Showing OMA ID matching OMA Exhibit, OMA Area, and OMA Type (Required)* *Provide table in this Attachment OR on OMA Exhibit in Attachment 1 a Form 1-7, Harvest and Use Feasibility Screening Checklist (Required unless the entire project will use infiltration BMPs) Refer to Appendix B.3-1 of the BMP Design Manual to complete Form 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. Pollutant Control BMP Design Worksheets I Calculations (Required) Refer to Appendices B and E of the BMP Design Manual for structural pollutant control BMP design guidelines ✓ Included ✓ Included on OMA Exhibit in Attachment 1 a D Included as Attachment 1 b, separate from OMA Exhibit D Included ✓ Not included because the entire project will use infiltration BMPs ✓ Included D Not included because the entire project will use harvest and use BMPs ✓ Included Use this checklist to ensure the required information has been included on the DMA Exhibit: The OMA Exhibit must identify: o Underlying hydrologic soil group • Approximate depth to groundwater • Existing natural hydrologic features (watercourses, seeps, springs, wetlands) • Critical coarse sediment yield areas to be protected (if present) • Existing topography and impervious areas • Existing and proposed site drainage network and connections to drainage offsite • Proposed grading • Proposed impervious features • Proposed design features and surface treatments used to minimize imperviousness • Drainage management area (OMA) boundaries, OMA ID numbers, and OMA areas (square footage or acreage}, and OMA type (i.e., drains to BMP, self-retaining, or self-mitigating) • Structural BMPs (identify location and type of BMP) DRAINAGE MANAGEMENT AREA EXHIBIT LEGEND SUBDIVISION BOUNDARY PROPERTY LINE I RIGHT-OF-WAY CENTERLINE OF ROAD ---------- \ SEE BELOW FOR SELF- MITIGA TING OMA B \ \ / I "\ I I I I I ' I I I I -.:: ~ l 11\ I I II ~ \ \ \ I II I I ~ I I \ I '~ \> b , b X - ----=:;;s== - ' ' \> I b , , ' I b b ~ , b , I> , b b b It , \> b b • b t· b , I> • ' ' X b\> , • b , b \> b. , ' , \> b b @ \> , ' v: ..... ' ""' \> , • , b --~= -- b , .,..._.i \;> • b -~ \> b b , /'• -.. J ,' ,.. ----------------·-·-·"·-····=·""=··-----, ,_ --___ '"' ··---·-·' \. \ \ \ \ \ I J;IActive Jobsl2808 Walnut RinconlCIVILIREPORTSISWQMPIAttachmentslAttachment 1. Pollutant Contro/lAtt 1a_b. OMA Exhibit.dwg ----·~···-----------------. 362 WALNUT AVENUE -·-·----·-·- --55 --· ------------ ~ - • / I> ' b I b \> X ---- b b \, i D \; . @ \4' \> , \, b \ 11 ·. b - PLAN VIEW -OMA EXHIBIT SCALE: 1" • 10' SOIL TYPE INFORMATION I> , b "'' X , ' ' r· ', b , • ' ' ' • ' I> " -=s= PROPOSED ROOF DOWNSPOUT (TYP.) SOIL TYPE B SOILS PER WEB SOIL SURVEY APPLICATION AVAILABLE THROUGH UNITED STATES DEPARTMENT OF AGRICULTURE GROUNDWATER INFORMATION GROUNDWATER WAS NOT ENCOUNTERED AT THE DEPTHS EXPLORED AT THE SITE. SEE REPORT TITLED "REPORT OF PRELIMINARY GEOTECHNICAL INVEST/GA TION PROPOSED WALNUT AVENUE RESIDENTIAL PROJECT"PREPARED BY GEOTECHNICAL EXPLORATION, INC. DATED NOVEMBER 14, 2017. DEPTHS OF GROUNDWATER EXPECTED APPROXIMATELY 50 FEET BELOW GROUND SURFACE COARSE SEDIMENT YIELD NO CRITICAL COARSE SEDIMENT YIELD AREAS TO BE PROTECTED. REFER TO PRIORITY DEVELOPMENT PROJECT SWQMP PREPARED BY PASCO, LARET, SUITER & ASSOCIATES TREATMENT CONTROL BMPS BIOFILTRATJON BASIN WITH PARTIAL RETENTION PR-1 55-·-- =D ,..._,,_-,., , .... -.. , _,_,-,,-.,.,,. .. ____ , .. , ...... ,. -· - \ \'""\'"·,-, -~, ~,-'\"\""""\. ·-\--\ \ X L_ \ ' \ I · ··••' f1. ~ 0 \> DEEP ROOTED, DENSE, DROUGHT TOLERANT PLANTING SUITABLE FOR WELL DRAINED SOIL NON-WOVEN GEOTEXTILE LINER IMPERVIOUS LINER 4" PERFORATED PIPE TO CONNECT TO BROOKS BOX NOTE: PIPE SHALL BE CENTERED IN IMP AND RUN ENTIRE LENGTH OF IMP \ \ I I • \ l> . ' , , / L -. b b , C-------;'• • b I / I I . ,! /:, I 1---,"1 ·---,-11 Ii 6 I "' * /' b t, • , \> / i;," /" /t, b 't> ,, ,; : l d --{'.i / 36" X 36" BROOKS BOX; 52.TTG TYPICAL OETAIL- BIOFIL TRA T/ON BASIN 12" PVC OUTLET DRAIN PIPE; IE PER PLAN SCALE: NTS ------------ w w j I \ l I t I f I I f I/ EXISTING CONTOUR LINE PROPOSED CONTOUR LINE OMA DRAINAGE BASIN BOUNDARY PROPOSED IMPERVIOUS AREA SELF-MIT/GA TING AREA POINT OF COMPLIANCE L + . + + +, + . + , + , +I © BASIN A AREA CAL GULA TIONS IMPERVIOUS AREA (BUILDING ROOF) 9,980SF (ADDITIONAL HARDSCAPE) 1,306 SF TOTAL 11,286 SF PERVIOUS AREA (LANDSCAPE) 9,434 SF (PERVIOUS DRIVEWAY) 3,000 SF (BIORETENTJON BASIN) 300SF TOTAL 12,734 SF TOTAL BASIN AREA 24,020SF % IMPERVIOUS AREA 47.0% OMA TABLE -TREATMENT (BASIN A) AREA AREA POST-PROJECT SURFACE ADJUSTMENT AREA X ADJUSTED RUNOFF NAME A1 A2 A3 A4 A5 A6 Al AB A9 (SF) SURFACE TYPE 955 UNIT 1 ROOF 1894 UNITS 2-3 ROOF 1894 UNITS 4-5 ROOF 2619 UNITS 6-8 ROOF 2619 UNITS 9-11 ROOF 3000 DRIVE AISLE 1306 PCC WALKWAYS 9434 LANDSCAPE 300 BMP BASIN TOTAL OMA SIZE = IMP SIZING FACTOR MIN. AREA REQUIRED = = FACTOR FACTOR 0.9 0.27 0.9 0.27 0.9 0.27 0.9 0.27 0.9 0.27 0.3 1 0.9 0.27 0.3 1 0.3 1 TOTAL 6,563 SF 0.03 (FOR BIORETENTION BMP'S) 0.03 • 6,563 SF= 197 SF RUNOFF (SF) 232 460 460 636 636 900 317 2830 90 6563 300 SF PROVIDED> 197 SF REQUIRED THEREFORE, OK FOR WATER QUALITY DCV CALCULATION TOTAL BASIN SIZE {A) = 24,020 SF I 0.552 AC TOTAL OMA SIZE (Cx • Ax) = 6,563 SF RUNOFF FACTOR (Cx) = 0.27 85TH PERCENTILE RAINFALL DEPTH (d) = 0.58 IN w---w---vv ocv rc·o·NJ,630J = 318CU FT 52.5 IE AND CONVEYANCE 2.0" WIDE WE:JR; . 4" FREEBOARD 24 • ABOVE RISER 2"HARDWOOD MULCH 0.5" HMP LOW-FLOW ·····'< .... ,_,-,J .. :. ,_,. ORIFICE; 46.5 IE '/ --;-, -7 V 18" ENGINEERED SOIL LA YER; "SEE NOTE BELOW IMPERVIOUS LINER 30" ¾" CRUSHED ROCK 3" PERFORATED PIPE WI FILTER PERFORATIONS AT THE INVERT MIN 3" AGGREGATE BELOW UNDERDRAIN GRAPHIC SCALE 1" = 10' 10 o 10 20 30 OMA EXHIBIT WALNUT BEACH HOMES -362 WALNUT AVE CITY OF CARLSBAD PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING 555 North B1ghway 101. Ste A. Snl•c: •emc'>, CA 92075 ph 858.259.8212 I ilt 158.259.4812 I ,~- PLSA 2808-01 Rincon Walnut Ave. Project 17-11664 Appendix I: Forms and Checklists Categorization of Infiltration Feasibility Form l-8 Condition Part J -Full Infiltration Feasibility Screeoioa: Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Cntena Screening Qucsaon Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? n,e response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide hasis: Yes No X The mfiltrabon test resulls below the proposed facility locations were 2.000 and 2.108 ,riches per hour with a minimum factor of safety of 2 applied. Simple open pit testing was performed at 2 locations on the site in accordance with Appendix D of the City of Carlsbad BMP design manual. In addition, a comprehensive evaluation or the slle was conducted in accordance with Appendix C.2. Please refer to our "Report of Preliminary Geotechnical Investigation· dated November 14, 2017 for details of the comprehensive evaluation and ,nvestigation conducted, simple open pit test rates and simple open pit rate to infiltration rate calculations and maps representative of the study. 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 ha%ards (slope stability, groundwater mounrung, 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: X The inf1hration test results below the proposed facihly locations ranged from 2.000 to 2.108 inches per hour with a minimum factor of safety of 2 applied. In our opinion, any long term full infillralion at the site will not result in geotechnical hazards which cannot be reasonable mitigated to an acceptable level. However, we recommend that the sidewalls of the proposed basins be hned. Please refer to our "Repoll of Preliminary Geotechnical Investigation• dated November 14, 2017 for details of the comprehensive evaluation and investigation conducted, simple open pit test rates and simple open pit rate to infiltration rate calculations and maps representative of the study. Sumn1arizc findings of sn1dics; provide reference to srudics, calculations, maps, data sources, etc. Provide narrative discussion o f study/ data source applicability. 1-3 February 2016 Rincon Walnut Ave. Project 17-11664 Appendix I: Forms and Checklists _ Form I-8 Page 2 of 4 C:rit1:ri a 3 Screening Question Can infiltration greater than 0 . .5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response tn this Screening Question sholl be based on a comprehensive evaluation of the factors presented in AppcnJi.x C.3. Provide basis: Yes No X The inflltralion test results below the proposed facility locations ranged trom 2.000 to 2.108 inches per hour with a minimum factor or safety or 2 applied. In our opinion, any long term full infiltration at the site will not resutt in a significant risk for groundwater related concerns. Please refer to our "Report of Preliminary Geotechnical Investigation· dated November 14, 2017 for details of the comprehensive evaluation and investigation conducted, simple open pil test rates and simple open pit rate to infiltration rate calculations and maps representative or the study. Summarize !indini,,s of studies; provide reference to sn,dics, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 4 Can infilttation greater than 0 . .5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? lbc response to this Screening Question shall be ba.scd on a comprehensive evaluation of the facwrs presented in Appendix C.3. ProviJe basis: X No adverse effects are expected as it relates to soi l and groundwater protection, change of seasonality of ephermeral streams, contaminated groundwater due to land use activities, etc. Full infiltration deemed feasible per guidelines of this worksheet. However, biofiltration basin proposed with underdrain (but unlined bottom) to capture and discharge runoff into a hardened system just downstream. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Pan 1 Result • If all answers to rows I -4 arc "Yes"• full infiltration design is potentially feasible. The feasibility scrcenini; category is Full Infiltration If any answer from row 1-4 is "No", infiltr-•tiun may he possible to some extent hut would nut generallr be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 Full Infiltration •To be completed usmg i,,arhcred site information and best profcss1onal Judgment cons,dcnng the definition of MEP 1n the MS4 Permit. Additional testing and/ or srudics may be required by the City to substantiate findings. 1-4 February 2016 Rincon Walnut Ave. Project 17-11664 Appendix I: Forms and Checklists - Form 1-8 Page 3 of 4 Part 2 -Partial Infiltration vs. No Infiltration Feasibili!y Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Screening Queuion Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive c,•aluation of 1.hc factors presented in Appendix C.2 and Appendix D. Provide baAfs: Yes No X The infiltration lest results below the proposed facility locations ranged from 2.000 to 2.108 inches per hour with a minimum factor ol salety ol 2 applied. Based on our innttration lest rates and limited geotechnical investigation of the site, it is our opinion that the soil and geologic conditions aHow for appreciable infiltration rates. Please refer to our "Report of Preliminary Geotechnical Investigation" dated November 14, 2017 for details of the comprehensive evatuabon and investigation conducted, simple open pit lest rates and simple open pit rate to infiltration rate calculations and maps representative or the study. Summarize findings of studies; pr°'·ide reference to studies, calculations, maps, data sources, etc. Pro\'idc narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of gcotcchnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? 11,e response to this Screening Question shall be based on a comprehensi\'e evaluation of the factors presented in Appendix C.2. Pro\'ide basis: X In our opinion, any long term partial inIInratIon at the site will not result in geolechnlcal hazards which cannot be reasonable mitigated to an acceptable level. However. we recommend \hat !he sidewalls of the proposed basins be lined. Please refer to our "Reporl of Preliminary Geotechnical Investigation" dated November 14, 2017 for details of \he comprehensive evaluaUon and lnvestigat,on conducted, simple open pit test rates and simple open pit rate to infiltration rate calculations and maps representative of \he study. Summarize: findio1,-s of studies; prm·idc reference: to studies, calculatiom, maps, data sources, ecc. Provide narrative discussion of stud)'/data source applicabilit)' and why it was not feasible to mitigate low infiltratirm rates. 1-5 February 2016 Criteria 7 Rincon Walnut Ave. Project 17-11664 Appendix I: Forms and Checklists Form 1-8 Page 4 of 4 , -I Screening Quesdon Can lnfilttatlon in any apptcciablc quantity be allowed without posing significant risk for ground1'·atcr related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall ht: based on a comprehensive evaluation of the factors presented in Appendix C.3. Yea No X Provide basis: In our opinion. any long term partial inftltralion at the site will not result ,n a significant risk for groundwater related concerns. Please refer to our "Report of Preliminary Geolechnical Investigation· dated November 14, 2017 for details of the comprehensive evaluation and investigation conducted, simple open pll test rales and simple open ptt rate to inf,ltrat,on rate calculations and maps representative of the study. Summarize findinl,lS of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of studr/data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Prodde basis: X Yes, there are currently no downstream properties w ith water rights in the watershed that will be affected if the subject property infiltrates as opposed to continuing to allow to drain freely from the site. Summarize findings of studies; provide reference t0 studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltrntion rates. Part 2 Result* If all answers from rnw 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltratio n. If any answer from row 5-8 is no, rheo infiltration of any volume is considered to be infeasible u-ithin the drainage area. The feasibility screening categnry is No Infiltration. '"To be completed using 1,,atheted site mforrnauon and best professional 1ud1,'1Tlent cons,denng the defin1t1on of MRP m the MS4 Permit. Additional testing and/ or studies may be required by the City to substantiate findings. 1-6 February 2016 Rincon Walnut Ave. Project 17-11664 Appendix I: Forms and Checklists -- Factor of Safety and Design Infiltration Rate Worksheet Form l-9 Factor Category Factor De~cnprion Assigned Factor Product (p) Weight (w) Value(,·) p =wxv Soil assessment mcth<Kls 0.25 2 0.5 Predominant soil texture 0.25 2 0.5 Suitabilitr Site soil variability 0.25 2 0.5 A Assessment Depth to h..,.oundwater I impervious layer 0.25 1 0.25 Suitability Assessment Safety Factor, S" = Ep 1.75 Level of pretreatment/ expected 0.5 sediment loads 13 Design Redundancy/ resiliency 0.25 Compaction during construcriun 0.25 Design Safety Factor, S1i = Ep Combined Safety Factor, S,0,o1= SI x So Obsen·ed Infiltration Rate, inch/hr, K,.,,,·n·«i (corrected for test-specific bias) Desii,, lnfiltrarion Rate, in/hr, Ki«'W': K,,t,,,n«I / s,,,,,1 Supporting Dat3 Briefly describe inf~traU<>n test and provide reference to test forms: Simple open pit testing was performed at 2 locations on the site per the requirements of !he City or Carlsbad Storm Water Standards, BMP Design Manual, in accordance with Appendix D. Please refer to our "Report of Preliminary Geotechnlcal Investigation" dated November 14, 2017 for details of the comprehensive ev~luat,on and investigation conducted, simple open pit test rates and simple open pit rate to lnfillrat,on rate calculations and maps representative of the study. 1-7 February 2016 1 2 3 4 5 6 Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods Worksheet B.2-1. DCV Design Capture Volume Worksheet B-2.1 85th percentile 24-hr storm depth from Figure B.1-1 d= 0.58 inches Area tributary to BMP (s) A= 0.552 acres Area weighted runoff factor (estimate using Appendix 0.27 B.1.1 and B.2.1) C= unitless Tree wells volume reduction TCV= -cubic-feet Rain barrels volume reduction RCV= -cubic-feet Calculate DCV = 318 (3630 x C x d x A) -TCV -RCV DCV= cubic-feet B-10 February 2016 Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods Worksheet B.5-1: Simple Sizing Method for Biofiltration BMPs -······•-=""'·il""''llll'""'•-''~- 1 Remaining DCV after implementing retention BMPs 318 cubic-feet Partial Retention 2 Infiltration rate from Form I-9 if partial infiltration is feasible -in/hr. 3 Allowable drawdown time for aggregate storage below the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches 5 Aggregate pore space 0.40 in/in 6 Required depth of gravel below the underdrain [Line 4/ Line 5] 0 inches 7 Assumed surface area of the biofiltration BMP 300 sq-ft 8 Media retained pore storage 0.1 in/in 9 Volume retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7 45 cubic-feet 10 DCV that requires biofiltration [Line 1 -Line 9] 273 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 inch maximum] 18 inches 12 Media Thickness [18 inches minimum], also add mulch layer thickness to this line for sizing calculations 18 inches 13 Aggregate Storage above underdrain invert (12 inches typical) -use 0 30 inches inches for sizing if the aggregate is not over the entire bottom surface area 14 Media available pore space 0.2 in/in 15 Media filtration rate to be used for sizing (5 in/hr. with no outlet control; 5 in/hr. if the filtration is controlled by the outlet, use the outlet controlled rate) Baseline Calculations 16 Allowable Routing Time for sizing 6 hours 17 Depth filtered during storm [ Line 15 x Line 16] 30 inches 18 Depth of Detention Storage 33.6 inches [Line 11 + (Line 12 x Line 14) + (Line 13 x Line 5)] 19 Total Depth Treated [Line 17 + Line 18] 63.6 inches Option 1-Biofilter 1.5 times the DCV 20 Required biofiltered volume [1.5 x Line 1 0] 410 cubic-feet 21 Reguired Footprint [Line 20/ Line 19] x 12 77 sg-ft Option 2 -Store 0.75 of remainiru!'. DCV in pores and pondiru!'. 22 Required Storage (surface + pores) Volume [0.75 x Line 10] 205 cubic-feet 23 Required Footprint [Line 22/ Line 18] x 12 73 sq-ft Footprint of the BMP 24 Area draining to the BMP 24,020 sq-ft 25 Adjusted Runoff Factor for drainage area (Refer to Appendix B.1 and B.2) 0.27 26 Minimum BMP Footprint [Line 24 x Line 25 x 0.03] 197 sq-ft 27 Footprint of the BMP = Maximum(Minimwn(Line 21, Line 23), Line 26) 300 sq-ft Note: Line 7 is used to eHimate the amount of volume retained by the BM I'. Update assumed surface area in I ,me 7 until its e4uivalcnt ru the required biofiltration fooq1rint (either Linc 21 or Linc 23) B-26 February 2016 Appendix E: BMP Design Fact Sheets E.11 PR-1 Biofiltration with Partial Retention Locatio11: 805 a11d Bonita Road, Chula vista, CA. Description MS4 Permit Cate o NA Manual Category Partial Retention -------Applicable Performance Standard Pollutant Control Flow Control Primary Benefits Volume Reduction Treatment Peak Flow Attenuation Biofiltration with partial retention (partial infiltration and biofiltration) facilities are vegetated surface water systems that filter water through vegetation, and soil or engineered media prior to infiltrating into native soils, discharge via underdrain, or overflow to the downstream conveyance system. Where feasible, these BMPs have an elevated underdrain discharge point that creates storage capacity in the aggregate storage layer. Biofiltration with partial retention facilities are commonly incorporated into the site within parking lot landscaping, along roadsides, and in open spaces. They can be constructed in ground or partially aboveground, such as planter boxes with open bottoms to allow infiltration. Treatment is achieved through filtration, sedimentation, sorption, infiltration, biochemical processes and plant uptake. Typical biofiltration with partial retention components include: • Inflow distribution mechanisms (e.g, perimeter flow spreader or filter strips) • Energy dissipation mechanism for concentrated inflows (e.g., splash blocks or riprap) • Shallow surface ponding for captured flows • Side Slope and basin bottom vegetation selected based on climate and ponding depth • Non-floating mulch layer (Optional) • Media layer (planting mix or engineered media) capable of supporting vegetation growth • Filter course layer consisting of aggregate to prevent the migration of fines into uncompacted native soils or the optional aggregate storage layer • Aggregate storage layer with underdrain(s) • Uncompacted native soils at the bottom of the facility • Overflow structure E-57 February 2016 Appendix E: BMP Design Fact Sheets SIDE SLOPE PLAN NOTTO SCALE . . .. . MAINTENANCE + ACCESS JAS ,!'IEE!)ED) + + 3H:1V (MIN.) + 4-6" DROP FROM CURB CUT TO APRON APRON FOR ENERGY DISSIPATION CURB CUT EXCAVATED SLOPE (SHOWN AT 1H:1V) MIN. 18" MEDIA WITH MINT 5 IN/HR FILTRATION RATE INFILTRATION STORAGE (MIN. 3" AGGREGATE BELOW UNDERDRAIN) AGGREGATE STORAGE LAYER 3" WELL-AGED, SHREDDED HARDWOOD MULCH 6" MIN. TO 12" MAX. SURFACE PONDING UNDERDRAIN FILTER COURSE EXISTING UNCOMPACTED SOILS SECTION A-A' NOTTO SCALE MAINTENANCE ACCESS (AS NEEDED) Typical plan and Section view of a Biofiltration with Partial Retention BMP E-58 February 2016 Appendix E: BMP Design Fact Sheets Design Adaptations for Project Goals Partial infiltration BMP with biofiltration treatment for storm water pollutant control. Biofiltration with partial retention can be designed so that a portion of the DCV is infiltrated by providing infiltration storage below the underdrain invert. The infiltration storage depth should be determined by the volume that can be reliably infiltrated within drawdown time limitations. Water discharged through the underdrain is considered biofiltration treatment. Storage provided above the underdrain within surface ponding, media, and aggregate storage is included in the biofiltration treatment volume. Integrated storm water flow control and pollutant control configuration. The system can be designed to provide flow rate and duration control by primarily providing increased surface ponding and/ or having a deeper aggregate storage layer. This will allow for significant detention storage, which can be controlled via inclusion of an orifice in an outlet structure at the downstream end of the underdrain. Design Criteria and Considerations Biofiltration with partial retention must meet the following design criteria and considerations. Deviations from the below criteria may be approved at the discretion of the City Engineer if it is determined to be appropriate: Siting and Design • • • Placement observes geotechnical recommendations regarding potential hazards (e.g., slope stability, landslides, liquefaction zones) and setbacks (e.g., slopes, foundations, utilities). Selection and design of basin is based on infiltration feasibility criteria and appropriate design infiltration rate (See Appendix C and D). Contributing tributary area shall be :S 5 acres (:S 1 acre preferred). E-59 Intent/Rationale Must not negatively impact existing site geotechnical concerns. Must operate as a partial infiltration design and must be supported by drainage area and in-situ infiltration rate feasibility findings. Bigger BMPs require additional design features for proper performance. Contributing tributary area greater than 5 acres may be allowed at the discretion of the City Engineer if the following conditions are met: 1) incorporate design features (e.g. flow spreaders) to minimizing short circuiting of flows in the BMP and 2) incorporate addition __ al __ February 2016 Siting and Design • Finish grade of the facility is :'.S 2%. Surface Ponding • • • • Surface ponding is limited to a 24-hour drawdown time. Surface ponding depth is 2: 6 and :'.S 12 inches. A minimum of 2 inches of freeboard is provided. Side slopes are stabilized with vegetation and are= 3H:1 V or shallower. ---------Vegetation E-60 Appendix E: BMP Design Fact Sheets Intent/Rationale design features requested by the City Engineer for proper performance of the regional BMP. Flatter surfaces reduce erosion and channelization within the facility. Surface ponding limited to 24 hours for plant health. Surface ponding drawdown time greater than 24-hours but less than 96 hours may be allowed at the discretion of the City Engineer if certified by a landscape architect or agronomist. Surface ponding capacity lowers subsurface storage requirements. Deep surface ponding raises safety concerns. Surface ponding depth greater than 12 inches (for additional pollutant control or surface outlet structures or flow- control orifices) may be allowed at the discretion of the City Engineer if tl1e following conditions are met: 1) surface ponding depth drawdown time is less than 24 hours; and 2) safety issues and fencing requirements are considered (typically ponding greater than 18" will require a fence and/ or flatter side slopes) and 3) potential for elevated clogging risk is considered. Freeboard provides room for head over overflow structures and minimizes risk of uncontrolled surface discharge. Gentler side slopes are safer, less prone to erosion, able to establish vegetation more quickly and easier to maintain. February 2016 Siting and Design • • Plantings are suitable for the climate and expected ponding depth. A plant list to aid in selection can be found in Appendix E.20 An irrigation system with a connection to water supply should be provided as needed. Mulch (Optional) • A minimum of 3 inches of well-aged, shredded hardwood mulch that has been stockpiled or stored for at least 12 months is provided. Mulch must be non-floating to avoid clogging of overflow structure. Media Layer • • Media maintains a minimum filtration rate of 5 in/hr over lifetime of facility. An initial filtration rate of 8 to 12 in/hr is recommended to allow for clogging over time; the initial filtration rate should not exceed 12 inches per hour. Media is a minimum 18 inches deep, meeting either of these two media specifications: City of San Diego Storm Water Standards Appendix F (February 2016, unless superseded by more recent edition) or County of San Diego Low Impact Development Handbook: Appendix G -Bioretention Soil Specification Qune 2014, unless superseded by more recent edition). Alternatively, for proprietary designs and custom media mixes not meeting the media specifications contained in the 2016 City of San Diego Storm Water Standards or County LID E-61 Appendix E: BMP Design Fact Sheets Intent/Rationale Plants suited to the climate and ponding depth are more likely to survive. Seasonal irrigation might be needed to keep plants healthy. Mulch will suppress weeds and maintain moisture for plant growth. Aging mulch kills pathogens and weed seeds and allows the beneficial microbes to multiply. A filtration rate of at least 5 inches per hour allows soil to drain between events, and allows flows to relatively quickly enter the aggregate storage layer, thereby minimizing bypass. The initial rate should be higher than long term target rate to account for clogging over time. However an excessively high initial rate can have a negative impact on treatment performance, therefore an upper limit is needed. A deep media layer provides additional filtration and supports plants with deeper roots. Standard specifications shall be followed. For non-standard or proprietary designs, compliance with Appendix F.1 ensures that adequate treatment performance will be provided. February 2016 Siting and Design • • Manual, the media meets the pollutant treatment performance criteria in Section F .1. Media surface area is 3% of contributing area times adjusted runoff factor or greater. Where receiving waters are impaired or have a TMDL for nutrients, the system is designed with nutrient sensitive media design (see fact sheet BF-2). Filter Course Layer • • • A filter course is used to prevent migration of fines through layers of the facility. Filter fabric is not used. Filter course is washed and free of fines. Filter course calculations assessing suitability for particle migration prevention have been completed. Aggregate Storage Layer E-62 Appendix E: BMP Design Fact Sheets Intent/Rationale Greater surface area to tributary area ratios: a) maximizes volume retention as required by the MS4 Permit and b) decrease loading rates per square foot and therefore increase longevity. Adjusted runoff factor is to account for site design BMPs implemented upstream of the BMP (such as rain barrels, impervious area dispersion, etc.). Refer to Appendix B.2 guidance. Use Worksheet B.5-1 Line 26 to estimate the minimum surface area required per this criteria. P otential for pollutant export is partly a function of media composition; media design must minimize potential for export of nutrients, particularly where receiving waters are impaired for nutrients. Migration of media can cause clogging of the aggregate storage layer void spaces or subgrade. Filter fabric is more likely to clog. Washing aggregate will help eliminate fmes that could clog the facility Gradation relationship between layers can evaluate factors (e.g., bridging, permeability, and uniformity) to determine if particle sizing is appropriate or if an intermediate layer is needed. February 2016 Siting and Design • • Class 2 Permeable per Caltrans specification 68-1.025 is recommended for the storage layer. Washed, open-graded crushed rock may be used, however a 4-6 inch washed pea gravel filter course layer at the top of the crushed rock is required. Maximum aggregate storage layer depth below the underdrain invert is determined based on the infiltration storage volume that will infiltrate within a 36-hour drawdown time. InDow, Underdrain, and OutDow Structures • • • • • • • Inflow, underdrains and outflow structures are accessible for inspection and maintenance. Inflow velocities are limited to 3 ft/ s or less or use energy dissipation methods. ( e.g., riprap, level spreader) for concentrated inflows. Curb cut inlets are at least 12 inches wide, have a 4-6 inch reveal (drop) and an apron and energy dissipation as needed. Underdrain outlet elevation should be a minimum of 3 inches above the bottom elevation of the aggregate storage layer. Minimum underdrain diameter is 6 inches. Underdrains are made of slotted, PVC pipe conforming to ASTM D 3034 or equivalent or corrugated, HDPE pipe conforming to AASHTO 252M or equivalent. An underdrain cleanout with a minimum 6- inch diameter and lockable cap is placed every 250 to 300 feet as required based on underdrain length. E-63 Appendix E: BMP Design Fact Sheets Intent/Rationale Washing aggregate will help eliminate fines that could clog the aggregate storage layer void spaces or subgrade. A maximum drawdown time is needed for vector control and to facilitate providing storm water storage for the next storm event. Maintenance will prevent clogging and ensure proper operation of the flow control structures. High inflow velocities can cause erosion, scour and/ or channeling. Inlets must not restrict flow and apron prevents blockage from vegetation as it grows in. Energy dissipation prevents erosion. A minimal separation from subgrade or the liner lessens the risk of fines entering the underdrain and can improve hydraulic performance by allowing perforations to remain unblocked. Smaller diameter underdrains are prone to clogging. Slotted underdrains provide greater intake capacity, clog resistant drainage, and reduced entrance velocity into the pipe, thereby reducing the chances of solids migration. Properly spaced cleanouts will facilitate underdrain maintenance. February 2016 Appendix E: BMP Design Fact Sheets Siting and Design Intent/Rationale • Overflow is safely conveyed to a downstream storm drain system or discharge point. Size overflow structure to pass 100-year peak flow for on-line infiltration basins and water quality peak flow for off-line basins. Planning for overflow lessens the risk of property damage due to flooding. Nutrient Sensitive Media Design To design biofiltration with partial retention with underdrain for storm water pollutant control only (no flow control required), the following steps should be taken: Conceptual Design and Sizing Approach for Storm Water Pollutant Control Only To design biofiltration with partial retention and an underdrain for storm water pollutant control only (no flow control required), the following steps should be taken: 1. Verify that siting and design criteria have been met, including placement requirements, contributing tributary area, maximum side and finish grade slopes, and the recommended media surface area tributary ratio. 2. Calculate the DCV per Appendix B based on expected site design runoff for tributary areas. 3. Generalized sizing procedure is presented in Appendix B.5. The surface ponding should be verified to have a maximum 24-hour drawdown time. Conceptual Design and Sizing Approach when Storm Water Flow Control is Applicable Control of flow rates and/ or durations will typically require significant surface ponding and/ or aggregate storage volumes, and therefore the following steps should be taken prior to determination of storm water pollutant control design. Pre-development and allowable post-project flow rates and durations should be determined as discussed in Chapter 6 of this manual. 1. Verify that siting and design criteria have been met, including placement requirements, contributing tributary area, maximum side and finish grade slopes, and the recommended media surface area tributary ratio. 2. Iteratively determine the facility footprint area, surface ponding and/ or aggregate storage layer depth required to provide detention and/ or infiltration storage to reduce flow rates and durations to allowable limits. Flow rates and durations can be controlled from detention storage by altering outlet structure orifice size(s) and/ or water control levels. Multi-level orifices can be used within an outlet structure to control the full range of flows. 3. If biofiltration with partial retention cannot fully provide the flow rate and duration control required by this manual, an upstream or downstream structure with significant storage volume such as an underground vault can be used to provide remaining controls. 4. After biofiltration with partial retention has been designed to meet flow control E-64 February 2016 Appendix E: BMP Design Fact Sheets requirements, calculations must be completed to verify if storm water pollutant control requirements to treat the DCV have been met. E-65 February 2016 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: Attachment Sequence Attachment 2a Contents Hydromodification Management Exhibit (Required) Attachment 2b Management of Critical Coarse Sediment Yield Areas (WMAA Exhibit is required, additional analyses are optional) Attachment 2c Attachment 2d 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. Flow Control Facility Design and Structural BMP Drawdown Calculations (Required) See Chapter 6 and Appendix G of the BMP Desiqn Manual Checklist ✓ Included See Hydromodification Management Exhibit Checklist on the back of this Attachment cover sheet. ✓ Exhibit showing project drainage boundaries marked on WMAA Critical Coarse Sediment Yield Area Map (Required) Optional analyses for Critical Coarse Sediment Yield Area Determination D 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 ✓ Included Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit: The Hydromodification Management Exhibit must identify: D Underlying hydrologic soil group D Approximate depth to groundwater D Existing natural hydrologic features ( watercourses, seeps, springs, wetlands) D Critical coarse sediment yield areas to be protected (if present) D Existing topography o Existing and proposed site drainage network and connections to drainage offsite D Proposed grading D Proposed impervious features o Proposed design features and surface treatments used to minimize imperviousness D Point(s) of Compliance (POC) for Hydromodification Management o Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) D Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) --=== \ '\ I I I I I I I J I I I I I \ ;g ' ' \> • ' ' ' v ' ' 1> ' ' · [ ', ' , \> ' ' , ' t '' ' ' \> ' ---·,::.,,. SOIL TYPE INFORMATION SOIL: TYPE B SOILS PER WEB SOIL SURVEY APPL/CATION AVAILABLE THROUGH UNITED STATES DEPARTMENT OF AGRICULTURE TREATMENT CONTROL BMPS BIOFILTRA TION BASIN WITH PARTIAL RETENTION PR-1 J:IActive Jobs\2808 Walnut RinconlCIVILIREPORTSISWQMPIAffachmentslAffachment 2 -HMPIAff 2a -HMP POST Exhibit.dwg -:::.:; ' ' ' ' X ,i;, ' , ' lt , ' t, ,· ' -, X HMPEXH/8/T 362 WALNUT AVENUE ' , \> ' ' t, , v ' \> , , ' ' ------ =s= - ' ' __ , t; -.-, , ' ,:;, • '· ' /·-- :1 , ' ' t, ' , ' \ I I )~ I \> ' ' I> " , ' • -, -=== - ))-, .. , , - GROUNDWATER INFORMATION ; ;-~ .:ff, :'-· " GROUNDWATER WAS NOT ENCOUNTERED AT THE DEPTHS EXPLORED AT THE SITE. SEE REPORT TITLED "REPORT OF PRELIMINARY GEOTECHNICAL INVEST/GA TION PROPOSED WALNUT AVENUE RESIDENTIAL PROJECI" PREPARED BY GEOTECHNICAL EXPLORATION, INC. DATED NOVEMBER 14, 2017. DEPTHS OF GROUNDWATER EXPECTED APPROX/MA TEL Y 50 FEET BELOW GROUND SURFACE. COARSE SEDIMENT YIELD NO CRITICAL COARSE SEDIMENT YIELD AREAS TO BE PROTECTED. REFER TO PRIORITY DEVELOPMENT PROJECT SWQMP PREPARED BY PASCO, LARET, SUITER & ASSOCIATES ------ ' \> : ' • I> ' ' , - X [ , , ' ----------=D -\ I I I I r J4 I / \ ' ' ' ' \ ' . _t:,"l_ 1,) \ ' . II ' \> . ' . ; i1 ' " ' \> ' ' \ ' • ' --~ ' -·~= X --X ,-. ,··, \ X D ' ' ' ' , ' ' ' ' . / ' -' ' ' L.--i ' \> • • t> '? '...__1;-· ,, t;'' ' \> /I / : \?"/ _/t:, ' ,: ' ' ' j I' al ' " '··~ w vv I l \ o' / .. ,,,,,, _ .. _,,,,,,,,.,,,,,,_,,,,,,.,, ,._,,, __ .. ,-,,,-~,,.,,,,, __ ,,,,,, __ ,--,,_.,,,,-, ,,,,,,, -"""--'""'"'-""''"'-·''"''"····-·-•----•·•--"·''.'ft ✓"" c:::)--'--w ~~-w ---if✓ ---w ~-\-\ \--\ \'\-· .. '\·-·\--\--·'\-·:\-~:\_S·\-\ \'\ \ \--,-\·\--\ \ '\ \·-·y·-·,-,--\-,---,·· Y'i\ 1~' _ iO : PLAN VIEW -OMA EXHIBIT SCALE: 1"= 10' DEEP ROOTED, DENSE, DROUGHT TOLERANT PLANTING SUITABLE FOR WELL DRAINED SOIL \--·- 36" X 36" BROOKS BOX: 52.lTG 2.0' WIDE WE:JR; 4" FREEBOARD 52.5 IE AND CONVEYANCE 24• ABOVE RISER 2"HARDWOOO MULCH 18" ENGINEERED SOIL I t, I I t , I f I NON-WOVEN - GEOTEXTILE LINER LA YER; 'SEE NOTE BELOW IMPERVIOUS LINER 4" PERFORATED PIPE TO CONNECT TO BROOKS BOX NOTE: PIPE SHALL BE CENTERED IN IMP AND RUN ENTIRE LENGTH OF IMP TYPICAL DETAIL - BIOFIL TRA TION BASIN SCALE: NTS VC OUTLET ORAi: ]- PIPE; IE PER PLAN 0.5" HMP LOW-FLOW ORIFICE; 46.5 IE . '_, __ , ::-- 30" ¾" CRUSHED ROCK 3" PERFORATED PIPE WI FILTER PERFORATIONS AT THE INVERT MIN 3" AGGREGATE BELOW UNDERDRAIN v LEGEND SUBDIVISION BOUNDARY PROPERTY LINE I RIGHT-OF-WAY CENTERLINE OF ROAD EXISTING CONTOUR LINE PROPOSED CONTOUR LINE OMA DRAINAGE BASIN BOUNDARY PROPOSED IMPERVIOUS AREA POINT OF COMPLIANCE BASIN A AREA CALCULATIONS IMPERVIOUS AREA (BUILDING ROOF) (ADDITIONAL HARDSCAPE) TOTAL PERVIOUS AREA (LANDSCAPE) (PERVIOUS DRIVEWAY) (BIORETENTION BASIN} TOTAL TOTAL BASIN AREA % IMPERVIOUS AREA ~ 10 0 HMPEXH/8/T ---------- ----····-·"·'-· ----4?·----------- 9,980SF 1,306 SF 11,286 SF 9,434SF 3,000 SF 300SF 12,734 SF 24,020SF 47.0% GRAPHIC SCALE 1" = 10' 10 20 30 WALNUT BEACH HOMES -362 WALNUT AVE CITY OF CARLSBAD PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING 535 North Highway 101., Ste A. Solalla Bnch. CA 112075 pb 858.259.8212 I fs 858.2511.4812 I~- PLSA 2808-01 DOWNSTREAM POINT OF COMPLIANCE 362 WALNUT AVENUE SCALE: NOT TO SCALE POINT OF COMPL IANCE EXHIB IT WALNUT BEACH HOMES -362 WALNUT AVE CITY OF CARLSBAD PASCO LARET SUITER & ASSOCIATES CIVIL ENGINEERING+ LAND PLANNING+ LAND SURVEYING 535 North Highway 101, Ste A, Solana Beach, CA 92075 ph 858.259.8212 I fit 858.259.4812 I plaaengineerlng.com PLSA 2808 CRITICAL COARSE SEDIMENT YIELD AREAS EXHIBIT 362 WALNUT A VENUE """,ECT SITE _,,., __ (DOES NOT CONTAIN CRfflCAL COARSE SEDIMENT YIELD AREAS) CR ~LCOARSE SEDIMENT YIELD AREAS SCALE: NOT TO SCALE CRITICAL COARSE SEDIMENT YIELD AREA EXHIBIT WALNUT BEACH HOMES-362 WALNUT AVE CITY OF CARLSBAD PASCO LAREY SUITER & ASSOCIATES CIVIL ENGINEERING+ LAND PLANNING+ LAND SURVEYING 535 North Highway 101, Ste A, Solana Beach, CA 92075 ph 858.259.8212 I fx 858.259.4812 I phaenglneerlng.com PLSA 2808 Drawdown Calculation for BMP-A Project Name p . N roJect 0 Surface Drawdown Time: Surface Area Surface Ponding (to invert of lowest surface discharge opening in outlet structure): Amended Soil Depth: Gravel Depth: Effective Depth Infiltration per Geotechnical Testing 362 Walnut Ave 2808 16.1 300 1.5 1.5 2.5 33.6 1.120 hr sq ft ft ft ft in in/hr 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: D 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: D 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) D How to access the structural BMP(s) to inspect and perform maintenance D 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) D Manufacturer and part number for proprietary parts of structural BMP(s) when applicable D 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.) D Recommended equipment to perform maintenance o When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management , ~ J J l l l 1 ' ... ] l • ] 1 1 l , 1 .. APPENDIX 3a BMP MAINTENANCE THRESHOLDS BMP DESCRIPTION BIOFIL TRA TION (300 SF) STORM WATER MANAGEMENT AND DISCHARGE CONffiOL MAINTENANCE AGREEMENT APPROVAL NO: ____ _ O&M RESPONSIBLE PARTY DESIGNEE: WALNUT BEACH HOMES HOA POST-CONSTRUCTION PERMANENT BMP OPERATION & MAINTENANCE PROCEDURE DETAILS MAINTENANCE IND/CA TORS ACCUMULATION OF SEDIMENT, LITTER, OR DEBRIS POOR VEGETATION ESTABLISHMENT OVERGROWN VEGETATION EROSION DUE TO CONCENTRATED /RR/GA TION FLOW EROSION DUE TO CONCENTRATED STORM WATER RUNOFF FLOW STANDING WATER IN BIOFIL TRA TION AREAS OBSTRUCTED INLET OR OUTLET STRUCTURE DAMAGE TO INLET OR OUTLET STRUCTURE MAINTENANCE [QUIPM[NT AND ACCESS US[ LANDSCAPE EQUIPMENT FOR MAINTENANCE; ACCESS BMP FROM PR/VAT[ ROAD AT NORTHEAST CORNER OF SIT£ INSPECTION FAG/LITA TION INSTALL 3' X 3' OUTLET RISER STRUCTURE TO PROVIDE OBSERVATION ACCESS FOR INSPECTION OF MAINTENANCE THRESHOLDS; MARKING TO BE PROVIDED ON BMP COMPONENTS TO DETERMINE HOW FULL BMP IS . MAINTENANCE ACTION REMOVE AND PROPERLY DISPOSE OF ACCUMULATED MATERIALS, WITHOUT DAMAGE TO THE VEGETATION RE-SEED, RE-PLANT, OR RE-ESTABLISH VEGETATION PER ORIGINAL PLANS MOW OR TRIM AS APPROPRIATE, BUT NOT LESS THAT THE DESIGN HEIGHT OF THE VEGETATION PER ORIGINAL PLANS. REPAIR/RE-SEED/RE-PLANT ERODED AREAS AND ADJUST THE /RR/GA TION SYSTEM REPAIR/RE-SEED/RE-PLANT ERODED AREAS AND MAKE APPROPRIATE CORRECTIVE MEASURES SUCH AS ADDING STONE AT FLOW ENTRY POINTS OR MINOR RE-GRADING TO RESTORE PROPER DRAINAGE ACCORDING TO THE ORIGINAL PLAN. 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W W -'--L/ -,7 -----'""'-.,.l I ~ \ "-"-,,,-" \' ,-,-,,,-,-,,-,, \ ",-" ', \ "-,-"-,-,-,, \ \"\ ,-, -_,-, V-, ' , w_ ~ -~ I I\ .\ i\ , , , , , \ \ \ \ \ \ \ \ \ \ \ \ \ , , \ , , \ \ \ \ \"""\,,,-.;;-D-,\-,-D -'\''\'\D,,,-m,~-:-'\ ,\-\7 POR. OF TRACT 219 \ OF THUM LANDS \ MAP NO. 1681 \ ' I APN: 204-132-18-00 \ PARTY RESPONSIBLE FOR MAINTENANCE: RINCON REAL ESTATE GROUP CONTACT: KEVIN DUNN 3005 S. EL CAMINO REAL SAN CLEMENTE, CA 92672 PH: (949) 438-5641 PLAN PREPARED BY: TYLER G LAWSON PASCO, LARET, SUITER & ASSOCIATES 535 N. HWY 101 , SUITE A SOLANA BEACH , CA 92075 PH: (858) 259-8212 BMP NOTES : No. 80356 Exp. 12/31/18 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. RE FER TO MAINTENANCE AGREEMENT DOCUMENT. 6. SEE PROJECT SWQMP FOR ADDITIONAL INFORMATION . BMP BMP ID# BMPTYPE SYMBOL CASQA NO. QUANTITY TREATMENT CONTROL 0 PERVIOUS PCC I . I TC-10 4,000 SF. PAVEMENT HYDROMODIFICATION & TR EATMENT CONTROL 0 BIO RETENTION ~ TC-32 300 SF. AREA LOW IMPACT DES IGN (L.LD.) 0 PERVIOUS PCC i • --_, I TC-10 4,000 SF. PAVEMENT @ -@ ROOF DRAIN TO • SD-11 TBD LANDSCAPING SOURCE CONTROL 0-@ STENCILS NO DUMPING SD-13 DRAINS TO OCEAN ® BMPSIGN PRIVATE YARD BMP NOTE I~;--<1 _--l 1 <1 • • ... _ <1 -~~-.. . . <J . sir=: Q I . / ., I h ; ,_ 7 I • ,J • 0 < -0 i •-. -I . APN: 204-132-26-00 ,q ). <J . . ·- . "'I 3Sfrf ~ \? J., ~ u, APN: 204-132-16-00 < . ,.r, _I .,'. "" . --'-' !I i ~s <7 . ' .t-· ·o ~ Ii! I I \ ii 1·1 \I ALL FUTURE IMPROVEMENTS WITHIN PRIVATE YA.~OS SHALL BE CONSTRUCTED OF PERV/OUS MATERIALS ONLY TABLE DRAWING NO. SHEET NO.(S) INSPECTION MAINTENANCE FREQUENCY FREQUENCY 2, 3 SEMI-ANNUALLY ANNUALLY 2,3,4 QUARTERLY SEMI-ANNUALLY 2,3 SEMI-ANNUALLY ANNUALLY --2,3 ANNUALLY ANNUALLY GRAPHIC SCALE 1": 10' 10 0 10 20 30 SINGL E SHEET BMP EXHIBIT WALNUT BEACH HOMES-362 WALNUT AVE CITY OF CARLSBAD PASCO LAREY SUITER & ASSOCIATES CIVIL ENGINEERING + LAND PLANNING + LAND SURVEYING 595 Morda JUahwar 101, Ste A. Solen• Pm:l,, icA !121175 ph 151.259,u12 I & 151.259,41121 plaunglneerlng.l:DDl PLSA 2808-01 ----ATTACHMENT 5 -SWMM Model Output and Support Documentation --.. -- ... --- , .. •• ------------... ---.. -... -... ... ----.. -... ---... ,.. ----------.. , -------- .. - -- Attachment Sa -Basin Geometry ---PASCO LARET SUITER & ASSOCIATES '.:3(£,2. (N/l..li1uJ lrve., -_ Date_l !~(;Jj__LfL_ Job# 1,-'S08 l rflAP f,,,hlkMiot1 'E.tsl• "Bl-<P-k ---------------------.-.i -- o:~~· · 3:x3 45<~e, -z.. --{:,.;( ( ~ 9J.( \1'-lt 'Fl'\)..' I'\ -:. '51, i3 ,Ct-..____, -\.1 ~ -- •· ------.. .... .. --.... --.. "1ik -'f1I 5: ct--1 L --ss,; Nmth Hi~hwav 101 Ste A Solana Beach, CA 92075 I plsaengincering.com Al+-+<' (p ... ----------------.... ---.. ---... --.... .. ------... - Attachment Sb -SWMM / Hydromodification Analysis Discussion -.. -.. -.. --... ... ---... ---.. ... ----------.. ---... -.. .. SWMM / Hydromodification Analysis/ Discussion 5.1 Hydromodification Analysis To satisfy the requirements of the MS4 Permit, a hydromodification management strategy has been developed for the project based on the Final Hydromodification Management Plan dated March 2011, (Final HMP). A continuous simulation model, the Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) version 5.1, was selected to size mitigation measures . The SWMM model is capable of modeling hydromodification management facilities to mitigate the effects of increased runoff from the post-development conditions and use changes that may cause negative impacts (i.e. erosion) to downstream channels. 5.1.1 Hydromodification Criteria Pursuant to the MS4 Permit, post-development runoff conditions (flow rates and durations) must not exceed pre-development runoff conditions by more than I 0% ( for the range of flows that result in increased potential for erosion, or degraded instream habitat downstream of the project. Based on the Final HMP: • For flow rates between the pre-project lower flow threshold (10%, 30%, or 50%) of the pre- project 2-year runoff event (0. lQ2, 0.3Q2, or 0.SQ2) to the pre-project IO-year event (Q10), the post-project discharge rates and durations may not deviate above the pre-project rates and durations by more than I 0% over more than 10% of the length of the flow duration curve . A channel screening analysis may be performed to determine a larger lower flow threshold, however for this project a lower flow threshold of 0.1 Q2 (high susceptibility) is assumed. 5.1.2 SWMM Model Development SWMM is a rainfall-runoff model used for single event or continuous simulation of runoff quantity from primarily urban areas. SWMM calculates and routes runoff based on user-specified input including precipitation data, subcatchment characteristics, soil data, routing information, and BMP configuration. SWMM is capable of modeling various hydrologic processes including but not limited to time-varying precipitation, evaporation, storage, infiltration, and retention LID facilities. 5.1.3 SWMM Input A pre-development and post-development model were created using the following global information: Parameter Inout Source Precioitation Oceanside Rainfall Data Proiect Clean Water Evaooration Encinitas ETo Zone Data CIMIS ETo Zones Mao Soils B USDA Web Soil Survev Annlication ---------------------.. -----------.... -.. -- The HMP biofiltration basin has been designed to comply with both pollutant control and hydromodification management criteria. Refer to Section 3.5 for the pollutant control calculations. The HMP biofiltration portion in the SWMM model is specified as an "LID Control" within the "Subcatchment" to define the ponding depth, biofiltration soil layer and gravel layer. 5.1.4 SWMM Processing and Output The HMP sizing was determined assuming a completely pervious existing site condition. The pre- development project 0.IQ2 and Q10 were determined to be 0.016 cfs and 0.35 cfs, respectively. After routing through the HMP biofiltration basin, the post-development, mitigated project 0.1 Q2 and Q10 were determined to be 0.006 cfs and 0.32 cfs leaving the site, respectively. Refer to the SWMM output included in Attachment 5 of the project SWQMP for detailed information and data from the SWMM model including input files, rain gage and evaporation data, and flow duration and frequency curves. Drawdown calculations are also included in Attachment 2 of the SWQMP. 5.2 Storm Water Pollutant Control To meet the requirements of the MS4 Permit, the HMP biofiltration facility is designed to treat onsite storm water pollutants contained in the volume of runoff from a 24-hour, 85th percentile storm event by filtering runoff through an engineered soil layer and gravel layer. 5.2.1 Numeric Sizing Requirements for Pollutant Control BMPs Pursuant to the MS4 Permit, Pollutant Control BMPs shall be designed to retain onsite pollutants contained in the post-development Design Capture Volume (DCV). The DCV is the volume of runoff resulting from the 24-hour, 85th percentile storm event. The DCV calculations for the project are located in Attachment I of the project SWQMP. The Pollutant Control BMP proposed for the project is an HMP biofiltration basin. The proposed HMP biofiltration basin does provide some retention, therefore pursuant to the MS4 Permit, the HMP biofiltration basin is designed to biofilter 1.0 times the DCV. ---·----Attachment Sc -Additional SWMM Support Documentation ------------------------.. ------ -... ---------... ---.. -... -----------,_ ------- 2808 362 Walnut Ave 1/8/2018 SWMM MODEL SCHEMATICS PRE-PROJECT MODEL Oceanside 12] OMA-A 1111 POC-1 .. POST-PROJECT MODEL Oceanside ~ OMA-A 1111 ' ' BMP-A • STOR1 BYPASS LOWFLOW OUTLETSTRUCTURE POC-1 ', DIV1 • J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_SWMM_Schematics.xlsx fl fl 1111 JI 1111111111 rt 111111 fl 11111111 2808 362 Walnut Ave 1/8/2017 PRE-PROJECT DMA Basin A 1 Area (ac) 0.551 Total: 0.551 POST-PROJECT DMA BMP Area (ac) A 1 0.54 BMP-1 1 0.00689 Total: 0.551 Infiltration: Width (Area/Flow Length) (ft) 141.3 Width (Area/Flow Length) (ft) 182.5 15.0 B:I 0.2lin/hr %Slope 0.7% % Impervious 47.6% 0% SWMMINPUT Weighted Weighted Weighted Infiltration Suction Head Initial % Impervious % "B" Soils % 11 C1 Soils % "D" Soils (in/hr): (in): Deficit: 0% 100% 0% 0% 0.200 3.000 0.310 Weighted Weighted Weighted Infiltration Suction Head Initial % Slope % 11B" Soils % "C" Soils % "D" Soils (in/hr): (in): Deficit: 1.0% 100% 0.0% 0% 0.200 3.000 0.310 0.0% 100% 0.0% 0% 0.200 3.000 0.310 Suction Head: Initial Deficit B:I 3lin B:I 0.31 I I I I r 1 I I I I I I [TITLE] ;;Project Title/Notes 2808 362 Walnut Ave Pre-Project Condition [OPTIONS] ; ;Option FLOW UNITS INFILTRATION FLOW ROUTING LINK OFFSETS MIN SLOPE ALLOW PONDING SKIP STEADY STATE START DATE START TIME REPORT START DATE REPORT START TIME END DATE END TIME SWEEP START SWEEP END DRY DAYS REPORT STEP WET STEP DRY STEP ROUTING STEP INERTIAL DAMPING NORMAL FLOW LIMITED FORCE_MAIN_EQUATION VARIABLE STEP LENGTHENING STEP MIN SURFAREA MAX TRIALS HEAD TOLERANCE SYS FLOW TOL --LAT FLOW TOL MINIMUM STEP THREADS Value CFS GREEN AMPT KINWAVE DEPTH 0 NO NO 08/28/1951 05:00:00 08/28/1951 05:00:00 05/23/2008 23:00:00 01/01 12/31 0 01:00:00 00:15:00 04:00:00 0:01:00 PARTIAL BOTH H-W 0. 7 5 0 12.557 8 0.005 5 5 0.5 1 [EVAPORATION] ; ; Data Source Parameters I J I 1 I I I I J I I I I I I I I I I I I l I 1 I I POC-1 I I I I r I I I I I I I r I t I I I I I I I I I I I I I I I I POC-1 MONTHLY .06 .08 .11 .15 .17 .19 .19 .18 .15 .11 .08 .06 DRY ONLY NO [RAINGAGES] ; ;Name Format Interval SCF Source . ·---------------------------------------------,, Oceanside INTENSITY 1: 00 1.0 TIMESERIES Oceanside [ SUBCATCHMENT S] ; ; Name Rain Gage Outlet Area %Imperv Width %Slope CurbLen SnowPack ,,-------------------------------------------------------------------------------------- DMA-A [SUBAREAS] ;;Subcatchment ; ; DMA-A [ INFILTRATION] ;;Subcatchment DMA-A [OUTFALLS] ; ;Name POC-1 [TIMESERIES] ; ;Name Oceanside POC-1 N-Irnperv N-Perv S-Irnperv 0.012 0.045 0.05 Suction Ksat IMO 3 0.2 0.31 Elevation Type Stage Data 0 FREE Date Time Value 0.551 0 141. 3 0.7 0 S-Perv PctZero RouteTo PctRouted 0 .1 25 OUTLET Gated Route To NO Oceanside FILE "J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Rain Data\oceanside.dat" [REPORT] ;;Reporting Options INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS 0.000 0.000 10000.000 10000.000 I I 1 I I I 1 I I I I r 1 I I I I I I I I I I I I f I I I I I I I I I I I I I I I I I I I POC-1 Units None [COORDINATES] ; ;Node X-Coord Y-Coord '' POC-1 990.019 4250.034 [VERTICES] ; ;Link X-Coord Y-Coord " [Polygons] ; ; Subcatchment X-Coord Y-Coord " OMA-A 967 .153 6520.681 [SYMBOLS] ; ;Gage X-Coord Y-Coord ;;--- Oceanside 1000.000 7500.000 I I I I f I I I I I ( I [TITLE] ;;Project Title/Notes 2808 362 Walnut Ave Post~Project Condition [OPTIONS] ;;Option FLOW UNITS INFILTRATION FLOW ROUT ING LINK OFFSETS MIN SLOPE ALLOW PONDING SKIP STEADY STATE START DATE START TIME REPORT START DATE REPORT START TIME --ENO DATE END TIME SWEEP START SWEEP END DRY DAYS REPORT STEP WET STEP DRY STEP ROUTING STEP INERTIAL DAMPING NORMAL FLOW LIMITED --FORCE_MAIN_EQUATION VARIABLE STEP LENGTHENING STEP MIN SURFAREA MAX TRIALS HEAD TOLERANCE SYS FLOW TOL --LAT FLOW TOL --MINIMUM STEP THREADS Value CFS GREEN AMPT KINWAVE DEPTH 0 NO NO 08/28/1951 05:00:00 08/28/1951 05:00:00 05/23/2008 23:00:00 01/01 12/31 0 01:00:00 00:15:00 04:00:00 0:01:00 PARTIAL BOTH H-W 0.75 0 12.557 8 0.005 5 5 0.5 1 [EVAPORATION] ; ; Data Source Parameters ; ; I I I I I I I I I I I I f l I I I I I I J I I I I I POC-1 I I I 1 ' I I t I I I I I I I I I 1 ( I I I I I I I I I I I I I f I I I I I POC-1 MONTHLY .06 . 08 .11 .15 .17 .19 .19 .18 .15 .11 .OB .06 DRY ONLY NO [RAINGAGES] ; ; Name Format Interval SCF Source ; ; Oceanside INTENSITY 1: 00 1.0 TIMESERIES Oceanside [SUBCATCHMENTS] ; ; Name Rain Gage Outlet Area %Imperv Width %Slope CurbLen SnowPack . ·--------------------------------------------------------------------------------------" OMA-A Oceanside BMP-A 0.54 47. 6 182.5 1 0 BMP-A Oceanside OIVl 0.00689 0 15 0 0 [SUBAREAS] ;;Subcatchment N-Imperv N-Perv S-Irnperv S-Perv PctZero RouteTo PctRouted ;;------------------- OMA-A 0.012 0.04 0.05 0.1 25 OUTLET BMP-A 0.012 0.06 0.05 0 .1 25 OUTLET [INFILTRATION] ;;Subcatchment Suction Ksat IMO ; ; OMA-A 3 0. 2 0.31 BMP-A 3 0.2 0.31 [ LID CONTROLS] ; ;Name Type/Layer Parameters ; ; BMP-A BC BMP-A SURFACE 25.64 0 0 0 5 BMP-A SOIL 18 0. 4 0.2 0.1 5 5 1.5 BMP-A STORAGE 30 0.67 1.12 0 BMP-A DRAIN 0.2729 0.5 0 6 [LID_ USAGE] ; ; Subcatchrnent LID Process Number Area Width InitSat Fromimp ToPerv RptFile DrainTo ;;------------------------------------------------------------------------------------------------------------- ------------------ BMP-A BMP-A 1 300.13 0 0 100 0 [OUTFALLS] ; ;Name Elevation Type Stage Data Gated Route To ;,---------------------------------------------------------- I I I I I I I I I I I I I I I I I I I I I I I I I l f I I I f ' t 1 I I POC-1 0 FREE NO POC-1 [DIVIDERS] ; ;Name Elevation Diverted Link Type Parameters DIVl [STORAGE] ;;Name IMO STORl [CONDUITS] ; ;Name BYPASS LOWFLOW [OUTLETS] ; ;Name 0 Elev. 0 From Node DIVl DIVl From Node OUTLETSTRUCTURE STORl [XSECTIONS J ; ;Link Shape . ·-------------------,, BYPASS DUMMY LOWFLOW DUMMY [CURVES] ; ;Name Type ,,----------------- RISER Rating RISER RISER RISER RISER RISER RISER RISER RISER RISER RISER BYPASS CUTOFF 0.015 0 0 0 0 MaxDepth InitDepth Shape 0. 5 0 To Node STORl POC-1 To Node POC-1 Geoml 0 0 X-Value ---------- 0 .05 .1 . 15 . 2 .25 . 3 . 35 .4 . 45 .5 Y-Value 0 .074 . 211 .387 . 596 1. 28 2.359 3.701 5.26 6.985 7.155 TABULAR Length 400 400 Offset 0 Georn2 0 0 Curve Name/Params N/A Fevap Psi Ksat STORl 0 0 Roughness InOffset OutOffset InitFlow MaxFlow -------------------------------------------------- 0,01 0 0.01 0 Type TABULAR/DEPTH Geom3 0 0 Geom4 0 0 0 0 0 0 0 0 QTable/Qcoeff Qexpon Gated ---------------------------------- RISER Barrels 1 1 NO Culvert I I I I I I I I I 1 I I I I I I I I I I STORl Storage 0 568 STORl . 5 671 [TIMESERIES] ; ; Name Date Time Value " Oceanside FILE "C:\2808\Rain Data\oceanside.dat" [REPORT] ;;Reporting Options INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] DIMENSIONS 0.000 0.000 10000.000 10000.000 Units None [COORDINATES] ; ;Node X-Coord Y-Coord " POC-1 975.217 3259.591 DIVl 1814.333 4701.566 STORl 176.836 4677.126 [VERTICES] ; ;Link X-Coord Y-Coord ; ; [Polygons] ;;Subcatchment X-Coord Y-Coord ;;-------------- OMA-A 982.687 6831. 4 93 BMP-A 1008.610 5626.066 [SYMBOLS] ; ; Gage X-Coord Y-Coord " Oceanside 1000.000 7500.000 I I I I I I I I I I I I I I I I I 1 f I POC-1 I 1 r I I 1 I I I I I I I I I I I I I I I I SWMM OUTPUT REPORT PRE-PROJECT CONDITION EPA STORM WATER MANAGEMENT MODEL -VERSION 5.1 (Build 5.1.010) 2808 362 Walnut Ave Pre~Project Condition ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Uni ts . . . . . . . . . . . . . . . CFS Process Models: Rainfall/Runoff ........ YES RDII ................... NO Snowme 1 t . . . . . . . . . . . . . . . NO Groundwater ............ NO Flow Routing ........... NO Water Quality .......... NO Infiltration Method ...... GREEN AMPT Starting Date ............ AUG-28-1951 05: 00: 00 Ending Date .............. MAY-23-2008 23: 00: 00 Antecedent Dry Days ...... 0.0 Report Time Step ......... 01:00:00 Wet Time Step ............ 00:15:00 Dry Time Step ............ 04:00:00 ************************** Runoff Quantity Continuity ************************** Total Precipitation ..... . Evaporation Loss ........ . Infiltration Loss ....... . Surface Runoff .......... . Final Storage ........... . Continuity Error (%) ************************** Flow Routing Continuity ************************** Dry Weather Inflow ...... . Wet Weather Inflow ...... . Volume acre-feet 30.998 0. 097 30.042 0.938 0.000 -0.259 Volume acre-feet 0.000 0.938 Depth inches 675.090 2.121 654.281 20.436 0.000 Volume 10'6 gal 0.000 0.306 I I I I J :\Active Jobs\2808 Walnut Rincon\CIVIL \REPORTS\SWMM\Output\2808_preProject_SWMM _results.docx I I I I I I I I I I I I I I I I I I I I I I I I SWMM OUTPUT REPORT Groundwater Inflow ...... . RDII Inflow ............. . External Inflow ......... . External Outflow ........ . Flooding Loss ........... . Evaporation Loss ........ . Exfiltration Loss ....... . Initial Stored Volume ... . Final Stored Volume ..... . Continuity Error ( % ) ••••• *************************** Subcatchment Runoff Summary *************************** Total Precip Subcatchment in OMA-A 675.09 l I 0.000 0.000 0.000 0.938 0.000 0.000 0.000 0.000 0.000 0.000 I I Total Runon in 0.00 Analysis begun on: Analysis ended on: Total elapsed time: Mon Jan 08 10:02:41 2018 Mon Jan 08 10:02:55 2018 00:00:14 I I I I I I PRE-PROJECT CONDITION 0.000 0.000 0.000 0.306 0.000 0.000 0.000 0.000 0.000 Total Total Evap Infil in in 2.12 654.28 I I Total Runoff in 20.44 I I I I I I I I Total Peak Runoff Runoff Runoff Coeff 10A6 gal CFS ------------------- 0.31 0.55 0.030 J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_PreProject_SWMM_results.docx I I I I I I I I I I I I I I I I I I I I I I I I I I I I SWMM OUTPUT REPORT POST-PROJECT CONDITION EPA STORM WATER MANAGEMENT MODEL -VERSION 5.1 (Build 5.1.010) 2808 362 Walnut Ave Post-Project Condition WARNING 04: minimum elevation drop used for Conduit BYPASS WARNING 04: minimum elevation drop used for Conduit LOWFLOW ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Uni ts . . . . . . . . . . . . . . . CFS Process Models: Rainfall/Runoff ....... . YES RDII .................. . NO Snowrnelt .............. . NO Groundwater ........... . NO Flow Routing .......... . YES Ponding Allowed ....... . NO Water Quality ......... . NO Infiltration Method ..... . GREEN AMPT Flow Routing Method ...... KINWAVE Starting Date ............ AUG-28-1951 05:00:00 Ending Date .............. MAY-23-2008 23:00:00 Antecedent Dry Days ...... 0.0 Report Time Step ......... 01:00:00 Wet Time Step ............ 00:15:00 Dry Time Step ............ 04:00:00 Routing Time Step ........ 60.00 sec ************************** Runoff Quantity Continuity ************************** Initial LID Storage ..... . Total Precipitation ..... . Evaporation Loss ........ . Infiltration Loss ....... . Surface Runoff .......... . LID Drainage ............ . Final Storage ........... . Continuity Error (%) .... . Volume acre-feet 0.001 30.767 2.740 22.089 0. 677 5.542 0.003 -0.920 Depth inches 0.023 675.090 60 .119 484.686 14.847 121. 612 0.059 I I I I I J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_PostProject_SWMM_results.docx I I I I I I I I I I I I 1 I 1 f I I I I I I I I 1 I I I 1 I I I 1 I I I I I I I 1 I SWMM OUTPUT REPORT ************************** Flow Routing Continuity Volume acre-feet ************************** Dry Weather Inflow ...... . Wet Weather Inflow ...... . Groundwater Inflow ...... . RDII Inflow ............. . External Inflow ......... . External Outflow ........ . Flooding Loss ........... . Evaporation Loss ........ . Exfiltration Loss ....... . Initial Stored Volume ... . Final Stored Volume ..... . Continuity Error (%) ******************************** Highest Flow Instability Indexes ******************************** All links are stable. ************************* Routing Time Step Summary ************************* Minimum Time Step Average Time Step Maximum Time Step Percent in Steady State Average Iterations per Step Percent Not Converging *************************** Subcatchment Runoff Summary *************************** Total Precip Subcatchment in 0.000 6.219 0.000 0.000 0.000 6.219 0.000 0.000 0.000 0.000 0.000 0.000 60.00 sec 60.00 sec 60.00 sec 0.00 1.00 0.00 Total Runon in POST-PROJECT CONDITION Volume 10'6 gal 0.000 2.027 0.000 0.000 0.000 2.027 0.000 0.000 0.000 0.000 0.000 Total Evap in Total Total Infil Runoff in in Total Runoff 10'6 gal ------------------------------------------------------------ OMA-A 675.09 0.00 49.12 341.61 290.64 4.26 BMP-A 67 5. 0 9 22778. 20 921.88 11698.57 10831. 36 2.03 J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_postProject_SWMM_results.docx Peak Runoff Runoff Coeff CFS 0.59 0.431 0.59 0.462 1 f I I I I 1 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I SWMM OUTPUT REPORT POST-PROJECT CONDITION *********************** LID Performance Summary *********************** Evap Infil Final Continuity Total Inflow in Loss Loss Surface Outflow in Drain Outflow in Initial Storage in Storage Error Subcatchment LID Control BMP-A BMP-A ****************** Node Depth Summary ****************** Node POC-1 DIVl STORl ******************* Node Inflow Summary ******************* Node Type OUTFALL DIVIDER STORAGE Type 23453.29 Average Maximum Depth Depth Feet Feet 0.00 0.00 0.00 0.00 0.00 0.20 Maximum Maximum Lateral Total Inflow Inflow CFS CFS in in 921. 91 11698. 94 1178.55 9653.16 1. 80 Maximum Time of Max Reported HGL Occurrence Max Depth Feet days hr :min Feet -------------------- 0.00 0 00:00 0.00 0.00 0 00:00 0.00 0.20 18857 11: 51 0.20 Lateral Total Flow Time of Max Inflow Inflow Balance Occurrence Volume Volume Error days hr:min 10'6 gal 10'6 gal Percent -------------------------------------------------------------------------- POC-1 OUTFALL 0.00 0.60 18857 11: 51 0 DIVl DIVIDER 0.59 0.59 18857 12:01 2.03 STORl STORAGE 0.00 0.58 18857 12:01 0 ********************** Node Surcharge Summary ********************** Surcharging occurs when water rises above the top of the highest conduit. Node Type Hours Surcharged Max. Height Above Crown Feet Min. Depth Below Rim Feet 2.03 2.03 0.219 J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_PostProject_SWMM_results.docx 0.000 0.000 0.004 in % 3.08 -0.00 I I I I I I I I I I I I I I I I I I I I I I I I r I I I I I I SWMM OUTPUT REPORT POST-PROJECT CONDITION DIVl STORl DIVIDER STORAGE ********************* Node Flooding Summary ********************* No nodes were flooded. ********************** Storage Volume Summary ********************** Average Volume Storage Unit 1000 ft] 497370.00 497370.00 Avg Evap Exfil Pent Pent Pent Full Loss Loss 0.000 0.196 Maximum Volume 1000 ft3 0.000 0.304 Max Pent Full Time of Max Occurrence days hr:min --------------------------------------------------------------------------- STORl 0.000 0 *********************** Outfall Loading Summary *********************** Flow Avg Outfall Node POC-1 System ******************** Link Flow Summary ******************** Link Freq Pent 2.16 2.16 Type Flow CFS 0.01 0.01 Maximum IFlowl CFS 0 0 0 .116 Max Total Flow Volume CFS 10A6 gal --------------- 0.60 2.026 ---------------- 0.60 2.026 Time of Max Maximum Occurrence IVelocl days hr:min ft/sec ----------------------------------------------- BYPASS DUMMY 0.58 18857 12:01 LOWFLOW DUMMY 0.02 141 07:10 37 18857 11: 50 Max/ Max/ Full Full Flow Depth J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_postProject_SWMM_results.docx I I I I I I I I I I I Maximum Outflow CFS 0.58 I I I I I I I I I I I I I I I I I I I I I I SWMM OUTPUT REPORT OUTLET STRUCTURE DUMMY POST-PROJECT CONDITION 0.58 18857 11:51 ************************* Conduit Surcharge Summary ************************* No conduits were surcharged. Analysis begun on: Mon Jan 08 09:57:13 2018 Analysis ended on: Mon Jan 08 09:57:44 2018 Total elapsed time: 00:00:31 I I I I I I J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\Output\2808_PostProject_SWMM_results.docx I I I I I I I I I I POC-1 Peak Flow Frequency Summary Return Period Pre-project Qpeak Post-project -Mitigated Q (ds) (ds) LF = 0.lxQ2 0.016 0.006 2-year 0.164 0.055 5-year 0.265 0.173 10-year 0.350 0.323 J:\Active Jobs\2808 Walnut Rincon\CIVIL\REPORTS\SWMM\2808_SWMM_PostProcessing_Alt6.xlsx "' -u 0.600 0.500 0.400 ·= ,: 0 0.300 ~ .:.: IV 41 Q. 0.200 0.100 0.000 POC-1 Peak Flow Frequency Curves I I ---I I I °T --~ _......;..,,~~ I I ..., r"' _.. _.., ~ r ~ I --~ . --! , I ~-r I ~~11 ~ I I .k~ "~~ I ! ~ ~ I I 0 1 2 3 4 5 6 Return Period in Years I j -<>-Pre-project Qpeak --6-Post-project Mitigated Qpeak ~ I I I I I I I CJ" ; --.... ---~ I --... --...,.---I .J.-~ I 'll":..-_.. ~ ~ . I 7 8 9 10 Low-flow Threshold:il 10% i POC-1 0.lxQ2 (Pre): 0.016 cfs Ql0 (Pre): 0.350 cfs Ordinate#: 100 Incremental Q (Pre): 0.00334 cfs Total Hourly Data:jJ 497370 I hours The proposed BMP:! PASSED Interval Pre-project Flow Pre-project Hours Pre-project % Post-project Post-project % Percentage Pass/Fail (cfs) Time Exceeding Hours Time Exceeding 0 0.016 129 2.59E-04 96 l.93E-04 74% Pass 1 0.020 126 2.53E-04 82 l.65E-04 65% Pass 2 0.023 120 2.41E-04 75 l.51E-04 63% Pass 3 0.026 118 2.37E-04 72 l.45E-04 61% Pass 4 0.030 115 2.31E-04 67 1.35E-04 58% Pass 5 0.033 114 2.29E-04 63 l.27E-04 55% Pass 6 0.036 108 2.17E-04 61 l.23E-04 56% Pass 7 0.040 106 2.13E-04 59 1.19E-04 56% Pass 8 0.043 106 2.13E-04 56 1.13E-04 53% Pass 9 0.046 97 l.95E-04 47 9.45E-05 48% Pass 10 0.050 94 l.89E-04 44 8.85E-05 47% Pass 11 0.053 94 l.89E-04 44 8.85E-05 47% Pass 12 0.056 90 l.81E-04 41 8.24E-05 46% Pass 13 0.060 84 l.69E-04 40 8.04E-05 48% Pass 14 0.063 82 1.65E-04 39 7.84E-05 48% Pass 15 0.066 80 1.61E-04 34 6.84E-05 43% Pass 16 0.070 67 1.35E-04 34 6.84E-05 51% Pass 17 0.073 66 1.33E-04 34 6.84E-05 52% Pass 18 0.077 64 1.29E-04 32 6.43E-05 50% Pass 19 0.080 64 l.29E-04 32 6.43E-05 50% Pass 20 0.083 64 1.29E-04 31 6.23E-05 48% Pass 21 0.087 63 l.27E-04 29 5.83E-05 46% Pass 22 0.090 60 l.21E-04 26 5.23E-05 43% Pass 23 0.093 57 l.15E-04 26 5.23E-05 46% Pass 24 0.097 55 1.llE-04 26 5.23E-05 47% Pass 25 0.100 53 l.07E-04 25 5.03E-05 47% Pass 26 0.103 53 1.07E-04 25 5.03E-05 47% Pass 27 0.107 53 l.07E-04 25 5.03E-05 47% Pass 28 0.110 50 1.0lE-04 25 5.03E-05 50% Pass 29 0.113 49 9.85E-05 25 5.03E-05 51% Pass 30 0.117 49 9.85E-05 25 5.03E-05 51% Pass 31 0.120 48 9.65E-05 25 5.03E-05 52% Pass 32 0.123 48 9.65E-05 25 5.03E-05 52% Pass 33 0.127 47 9.45E-05 25 5.03E-05 53% Pass 34 0.130 46 9.25E-05 24 4.83E-05 52% Pass 35 0.133 46 9.25E-05 24 4.83E-05 52% Pass 36 0.137 44 8.85E-05 21 4.22E-05 48% Pass 37 0.140 41 8.24E-05 21 4.22E-05 51% Pass 38 0.143 40 8.04E-05 20 4.02E-05 50% Pass 39 0.147 38 7.64E-05 19 3.82E-05 50% Pass 40 0.150 38 7.64E-05 19 3.82E-05 50% Pass 41 0.153 37 7.44E-05 18 3.62E-05 49% Pass 42 0.157 35 7.04E-05 16 3.22E-05 46% Pass 43 0.160 34 6.84E-05 16 3.22E-05 47% Pass 44 0.163 33 6.63E-05 16 3.22E-05 48% Pass 45 0.167 32 6.43E-05 15 3.02E-05 47% Pass 46 0.170 32 6.43E-05 15 3.02E-05 47% Pass 47 0.173 32 6.43E-05 15 3.02E-05 47% Pass 48 0.177 32 6.43E-05 15 3.02E-05 47% Pass 49 0.180 31 6.23E-05 15 3.02E-05 48% Pass 50 0.183 31 6.23E-05 14 2.81E-05 45% Pass 51 0.187 29 5.83E-05 14 2.81E-05 48% Pass 52 0.190 28 5.63E-05 13 2.61E-05 46% Pass 53 0.193 27 5.43E-05 13 2.61E-05 48% Pass 54 0.197 27 5.43E-05 13 2.61E-05 48% Pass 55 0.200 26 5.23E-05 12 2.41E-05 46% Pass 56 0.203 23 4.62E-05 12 2.41E-05 52% Pass 57 0.207 21 4.22E-05 12 2.41E-05 57% Pass 58 0.210 21 4.22E-05 11 2.21E-05 52% Pass 59 0.213 21 4.22E-05 11 2.21E-05 52% Pass 60 0.217 20 4.02E-05 11 2.21E-05 55% Pass 61 0.220 19 3.82E-05 11 2.21E-05 58% Pass 62 0.223 19 3.82E-05 11 2.21E-05 58% Pass 63 0.227 19 3.82E-05 10 2.0lE-05 53% Pass 64 0.230 19 3.82E-05 10 2.0l E-05 53% Pass 65 0.233 19 3.82E-05 10 2.0lE-05 53% Pass 66 0.237 18 3.62E-05 10 2.0l E-05 56% Pass 67 0.240 18 3.62E-OS 10 2.0lE-05 56% Pass 68 0.243 17 3.42E-05 10 2.0lE-05 59% Pass 69 0.247 17 3.42E-05 10 2.0lE-05 59% Pass 70 0.250 17 3.42E-05 10 2.0lE-05 59% Pass 71 0.254 16 3.22E-05 10 2.0lE-05 63% Pass 72 0.257 16 3.22E-05 10 2.0lE-05 63% Pass ----- Interval Pre-project Flow Pre-project Hours Pre-project % Post-project Post-project % Percentage Pass/Fail (cfs) Time Exceeding Hours Time Exceeding 73 0.260 16 3.22E-05 9 1.81E-05 56% Pass 74 0.264 15 3.02E-05 9 1.81E-05 60% Pass 75 0.267 13 2.61E-05 9 1.81E-05 69% Pass 76 0.270 12 2.41E-05 9 1.81E-05 75% Pass 77 0.274 12 2.41E-05 9 1.81E-05 75% Pass 78 0.277 9 1.81E-05 9 1.81E-05 100% Pass 79 0.280 9 1.81E-05 9 1.81E-05 100% Pass 80 0.284 9 1.81E-05 8 1.61E-05 89% Pass 81 0.287 8 1.61E-05 8 1.61E-05 100% Pass 82 0.290 8 1.61E-05 8 1.61E-05 100% Pass 83 0.294 8 1.61E-05 8 1.61E-05 100% Pass 84 0.297 8 1.61E-05 8 1.61E-05 100% Pass 85 0.300 7 1.41E-05 7 1.41E-05 100% Pass 86 0.304 7 1.41E-05 6 1.21E-05 86% Pass 87 0.307 6 1.21E-05 6 1.21E-05 100% Pass 88 0.310 6 1.21E-05 6 1.21E-05 100% Pass 89 0.314 6 1.21E-05 6 1.21E-05 100% Pass 90 0.317 6 1.21E-05 6 1.21E-05 100% Pass 91 0.320 6 1.21E-05 6 1.21E-05 100% Pass 92 0.324 6 1.21E-05 6 1.21E-05 100% Pass 93 0.327 6 1.21E-05 6 1.21E-05 100% Pass 94 0.330 6 1.21E-05 6 1.21E-05 100% Pass 95 0.334 6 1.21E-05 5 1.0lE-05 83% Pass 96 0.337 5 1.0lE-05 5 1.0lE-05 100% Pass 97 0.340 5 1.0lE-05 5 1.0lE-05 100% Pass 98 0.344 5 1.0lE-05 5 1.0lE-05 100% Pass 99 0.347 5 l.OlE-05 5 1.0lE-05 100% Pass 100 0.350 5 1.0lE-05 5 l.OlE-05 100% Pass -------------- -.l!! ~ 3 0 u:: 0.400 0.350 i 0.300 i r I 0.250 I 0.200 I 0.150 I 0.100 I 0.050 I 0.000 1.0E-06 I • I I I I : I I I .l. I ! Il l POC-1 Flow Duration Curve [Pre vs. Post (Mitigated)] I I l . I ! I I I I I I I I I I I ..,. ' I I I i l 61--~'ll : I I 1 I I i i I I I "'Ill I I I 1 ! I ~ ~ '~ I l I I I l I I' zl E~ ~ i I I ~ 1b . I ! I ~' '"\,I 1 I ,u , ~ I I I I I i II~ l .0E-05 l.0E-04 % Time Exceeding ----~ ~ Pre-project Q ~-~ -ti-Post-project (Mitigated) Q I I I I I I I I J I I I I I l.0E-03 l.0E-02 POC-1 SWMM Model Flow Coefficient Calculation and Effective Ponding Depth Calculation BMP-A PARAMETER ABBREV. Bio-Retention Cell LID BMP Ponding Depth PD 18 in Bioretention Soil Layer s 18 in Gravel Layer G 30 in TOTAL 5.5 ft 66 in Orifice Coefficient Cg 0.6 Low Flow Orifice Diameter D 0.5 in Drain exponent n 0.5 Flow Rate (volumetric) Q 0.015 cfs Ponding Depth Surface Area Apo 568 ft2 Bioretention Surface Area As.AG 300 ft2 As.AG 0.0069 ac Porosity of Bioretention Soil n 1.00 Flow Rate (per unit area) q 2.213 in/hr Effective Ponding Depth PDeff in Flow Coefficient C Pond Report Hydraflow Hydrographs Extension for AutoCAD® Civil 30® 2016 by Autodesk, Inc. v10.5 Pond No. 7 -STOR BMP-A Alt 6 Pond Data Contours -User-defined contour areas. Conic method used for volume calculation. Begining Elevation = 101.50 ft Stage I Storage Table Stage (ft) Elevation (ft) Contour area (sqft) Iner. Storage (cuft) Total storage (cuft) 0.00 101.50 568 0 0 0.50 102.00 671 309 309 Culvert/ Orifice Structures Weir Structures [AJ [BJ [CJ [PrfRsrJ [AJ [BJ Rise (in) 12.00 0.00 0.00 0.00 Crest Len (ft) 12.00 2.00 Span (in) = 12.00 0.00 0.00 0.00 Crest El. (ft) 101.70 101.50 No. Barrels 1 0 0 0 WeirCoeff. = 3.33 3.33 Invert El. (ft) = 96.00 0.00 0.00 0.00 Weir Type = 1 Rect Length (ft) = 117.00 0.00 0.00 0.00 Multi-Stage = Yes Yes Slope (%) = 1.50 0.00 0.00 n/a N-Value = .013 .013 .013 n/a Orifice Coeff. = 0.60 0.60 0.60 0.60 Exfil.(in/hr) = 0.000 (by Contour) Multi-Stage = nla No No No TW Elev. (ft) = 0.00 Monday, 01 / 8 / 2018 [CJ [DJ Inactive 0.00 101 .50 0.00 0.68 3.33 30 degV Yes No Note: Culvert/Orifice outflows are analyzed under inlet (ic) and outlet (oc) control. Weir risers checked for orifice conditions (ic) and submergence (s). Stage / Storage I Discharge Table Stage Storage Elevation ClvA ClvB ClvC PrfRsr WrA WrB Wr C WrD Exfil User Total ft cuft ft cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs cfs 0.00 0 101.50 0.00 0.00 0.00 0.000 0.05 31 101.55 6.96 oc 0.00 0.07 0.074 0.10 62 101.60 6.96 oc 0.00 0.21 0.211 0.15 93 101.65 6.96 oc 0.00 0.39 0.387 0.20 124 101.70 6.96 oc 0.00 0.60 0.596 0.25 155 101. 75 6.96 oc 0.45 0.83 1.280 0.30 186 101.80 6.96 oc 1.26 1.09 2.359 0.35 217 101.85 6.96 oc 2.32 1.38 3.701 0.40 247 101.90 6.96 oc 3.57 1.69 5.260 0.45 278 101.95 6.99 oc 5.00 1.99 s 6.985 0.50 309 102.00 7.16 oc 5.50 s 1.66 s 7.155 PASCO LARET SUITER & ASSOC IATES :St.?·2.. WtUvH.,<J irv~ Date_/ ~~.Lili--Job# 1,.'808 -300 'BvHd l4er O 0,'5-,~~ or1 hu- 535 North Highway 101 Ste A Solana Beach, CA 92075 I plsaengineering.com A~· Ip Drawdown Calculation for BMP-A Project Name P . tN roJec 0 Surface Drawdown Time: Surface Area Surface Ponding (to invert of lowest surface discharge opening in outlet structure): Amended Soil Depth: Gravel Depth: Effective Depth Infiltration per Geotechnical Testing 362 Walnut Ave 2808 16.1 300 1.5 1.5 2.5 33 .6 1.120 hr SQ ft ft ft ft in in/hr 33' g 23' N 33' g 18"N ~ iR ~ Hydrologic Soil Group-San Diego County Area, California I I I i I ~ ifiltt'J) ifiltt'J) ~ iR ~ N ~ A 467400 467fiJJ 4l7!0'.l 4675«) li5F.H) li5F.H) li5lfro 467400 467fiJJ ~ 4675«) lf5F.i1J li5F.H) li5lfro Map Scale: 1:1,140 if printEd on A landscape (11" X 8.5") sheet ~---=====-------=======Meiers 00 0 15 3'.l a:J ~---=====-------=======feet 3)) o ~ m ~ Map projection: Web Mercator Comer axronates: WGS84 Edge tics: UTM Zme 11N WGS84 USDA Natural Resources Web Soil Survey National Cooperative Soil Survey · em Conservation Service 46763J 46762) 4676«) 46ifflJ 4671:8) 4676«) 46ifflJ 4671:8) 467100 467100 ~ ~ ~ ~ ~ ~ ~ ~ I i I I I i 12/11/2017 Page 1 of4 33' g ZJ" N 33' g 18" N Hydrologic Soil Group-San Diego County Area, California MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons D A D A/o DB • s,o D C 0 C/0 D 0 D Not rated or not available Soil Rating Lines -A -A/0 -B -8/0 C -CJD -0 ,. ,, Not rated or not available Soil Rating Points • A • A/0 • B • 8/0 USDA Natural Resources --Conservation Service CJ C • CID • 0 • Not rated or not available Water Features Streams and Canals Transportation +++ Rails ,,,,., Interstate 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 12, Sep 13, 2017 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. 12/11/2017 Page 2 of 4 Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Map unit symbol I Map unit name I Rating I Acres In AOI Percent of AOI MIC Marina loamy coarse I B sand, 2 to 9 percent slopes 2.4 Totals for Area of Interest 2.4 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 (AID, BID, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (AID, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition USDA Natural Resources -Conservation Service Web Soil Survey National Cooperative Soil Survey 100.0% 100.0% 1 12/11/2017 Page 3 of 4 Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing Factors Figure G.1-2: California Irrigation Management Information System "Reference Evapotranspiration Zones" G-5 February 2016 Appendix G: Guidance for Continuous Simulation and Hydromodification Management Sizing Factors Table G.1-1: Monthly Average Reference Evapotranspiration by ETo Zone (inches/month and inches/day) for use in SWMM Models for Hydromodification Management Studies in San Diego County CIMIS Zones 1, 4, 6, 9, and 16 (See CIMIS ETo Zone Map) Zone I in/month in/month in/month in/month in/month in/month in/month in/month in/month in/month in/month in/month 0.93 1.4 2.48 3.3 4.03 4.5 4.65 4.03 3.3 2.48 1.2 0.62 4 1.86 2.24 3.41 4.5 5.27 5.7 5.89 5.58 4.5 3.41 2.4 1.86 6 1.86 2.24 3.41 4.8 5.58 6.3 6.51 6.2 4.8 3.72 2.4 1.86 9 2.17 2.8 4.03 5.1 5.89 6.6 7.44 6.82 5.7 4.03 2.7 1.86 16 1.55 2.52 4.03 5.7 7 75 8.7 9.3 8.37 6.3 4.34 2.4 1.55 Dav~ 31 28 31 30 31 30 31 31 30 31 30 31 Zone in/day in/day in/dav in/day in/day in/day in/dav in/ <lav in/day in/day in/day in/da, 0.030 0.050 0.080 0.110 0.130 0.150 0.150 0.130 0.110 0.080 0.040 0.020 4 0.060 0.080 0.110 0.150 0.170 0.190 0.190 0.180 0.150 0.110 0.080 0.060 6 0.060 0.080 0.110 0.160 0.180 0.210 0.210 0.200 0.160 0.120 0.080 0.060 9 0070 0.100 0.130 0.170 0.190 0.220 0.240 0.220 0.190 0.130 0.090 0.060 16 0.050 0.090 0.130 0.190 0.250 0.290 0.300 0.270 0.210 0.140 0.080 0.050 G-6 February 2016