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Home My WebLink AboutCT 04-14A; TRAILS END; PRIORITY DEVELOPMENT PROJECT (PDP) STORM WATER QUALITY MANANGEMENT PLAN (SWQMP); 2019-08-19I I I I I I I I I I I CT Uf-ltfA ---~-------. RECORD COPY Initial to f ,CfJL~ Date ··.: ··::: ·: ... Bruce A. Tait, C032247, 12/3l/1.8 PREPARED FOR: RECORD COPY \)~{l_. Initial The PEV Family Revocable Trust/ Pacifica Real Estate Services 5505 Cancha De Golf Rancho Santa Fe, CA 92091 858-7 55-0216 PREPARED BY: Masson & Associates, Inc. 200 E. Washington Ave. Suite 200 Escondido, California 92025 760-7 41-3570 DATE: March 31 201 RECEIVED MAY 1'"7 2017 LAND DEVELOPMENT ENGINEERING -<1 I-I--~ a: --Cf_ -<( 2 -LL TABLE OF CONTENTS ► CERTIFICATION PAGE PROJECT ► VICINITY MAP ► FORM E-34 STORM WATER STANDARD QUESTIONNAIRE SITE INFORMATION ► FORM E-36 STANDARD PROJECT REQUIREMENT CHECKLIST SUMMARY OF PDP STRUCTURAL BMPS ► ATTACHMENT 1: BACKUP FOR PDP POLLUTANT CONTROL BMPS 0 ATTACHMENT lA: DMA EXHIBIT 0 ATTACHMENT lB: TABULAR SUMMARY OF DMAS AND DESIGN CAPTURE VOLUME CALCULATIONS 0 ATTACHMENT lC: HARVEST AND USE FEASIBILITY SCREENING (WHEN APPLICABLE) 0 ATTACHMENT lD: CATEGORIZATION OF INFILTRATION FEASIBILITY CONDITION (WHEN APPLICABLE) 0 ATTACHMENT lE: POLLUTANT CONTROL BMP DESIGN WORKSHEETS/ CALCULATIONS ► ATTACHMENT 2: BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES 0 ATTACHMENT 2A: HYDROMODIFICATION MANAGEMENT EXHIBIT 0 ATTACHMENT 2B: MANAGEMENT OF CRITICAL COARSE SEDIMENT YIELD AREAS 0 ATTACHMENT 2C: GEOMORPHIC ASSESSMENT OF RECEIVING CHANNELS O ATTACHMENT 2D: FLOW CONTROL FACILITY DESIGN ► ATTACHMENT 3: STRUCTURAL BMP MAINTENANCE THRESHOLDS AND ACTIONS ► ATTACHMENT 4: SINGLE SHEET BMP (SSBMP) EXHIBIT CERTIFICATION PAGE Project Name: Trails End Development Project ID: CT04-14A 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. C032247 12/31 /18 Engineer of Work's Signature, PE Number & Expiration Date Bruce Tait P.E. Print Name '.•· Masson & Associates, Inc. Company March 31, 2017 Date PROJECT VICINITY MAP CJJY OF OCEANSIDE PACFIC OCEAN "' YICNIY MAP NOT TO sc,u:; 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: Trails End Development PROJECT ID: CT04-14A ADDRESS: (street number not assigned) Donna Drive, Carlsbad CA APN : 156-090-41-00 The project is (check one): lx]New Development c:Bedevelopment The total proposed disturbed area is: 121 532 ft2 ( 2.79) acres The total proposed newly created and/or replaced impervious area is : 90.169 ft2 ( 2.07 ) 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: No Project ID NIA SWQMP#: Then, go to Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city. E-34 Page 1 of 4 REV 02/16 STEP1 TO BE COMPLETED FOR ALL PROJECTS To determine if your project is a "development project", please answer the following question: YES NO Is your project LIMITED TO routine maintenance activity and/or repair/improvements to an existing building □ ■ or structure that do not alter the size (See Section 1.3 of the BMP Design Manual for guidance)? If you answered "yes" to the above question, provide justification below then go to Step 5, mark the third box stating "my project is not a 'development project' and not subject to the requirements of the BMP manual" and complete applicant information. Justification/discussion: (e.g. the project includes only interior remodels within an existing building): If you answered "no" to the above question, the project is a 'development project', ao 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 newor 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; □ ■ 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 USE PA Green Streets guidance? 2. Retrofitting or redeveloping existing paved alleys, streets, or roads that are designed and constructed in □ ■ 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? □ ■ 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 "m y 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 USE PA Green Street guidance): If you answered "no" to the above questions, your project is not exempt from PDP, go to Step 3. STEP3 TO BE COMPLETED FOR ALL NEW OR REDEVELOPMENT PROJECTS To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(1 )): YES NO 1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collectively over the entire project site? This includes commercial, industrial, residential, mixed-use, ■ □ and public development projects on public or private land. 2. Is your project a redevelopment project creating and/or replacing 5,000 square feet or more of impervious surface collectively over the entire project site on an existing site of 10,000 square feet or □ ■ more of impervious surface? This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. 3. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a restaurant? A restaurant is □ ■ a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812). 4. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious ■ □ surface collectively over the entire project site and supports a hillside development project? A hillside development project includes development on any natural slope that is twenty-five percent orqreater. 5. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a parking lot? A parking lot is □ ■ a land area or facility for the temporary parking or storage of motor vehicles used personally for business or for commerce. 6. Is your project a new or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface collectively over the entire project site and supports a street, road, highway ■ □ freeway or driveway? A street, road, highway, freeway or driveway is any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. 7. Is your project a new or redevelopment project that creates and/or replaces 2,500 square feet or more of impervious surface collectively over the entire site, and discharges directly to an Environmentally □ ■ Sensitive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not comminqled with flows from adjacent/ands).* 8. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface that supports an automotive repair shop? An automotive repair □ ■ shop is a facility that is categorized in any one of the following Standard Industrial Classification (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539. 9. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious area that supports a retail gasoline outlet (RGO)? This category includes □ ■ RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of 100 or more vehicles per day. 10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land ■ □ 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) If you answered "yes" to one or more of the above questions, your project is a PDP. If your project is a redevelopment project, go to step 4. If your project is a new project, go to step 5, check the first box stating "My project is a PDP ... " and complete applicant information. If you answered "no" to all of the above questions, your project is a 'STANDARD PROJECT.' Go to step 5, check the second box statinq "My project is a 'STANDARD PROJECT' ... " and complete aoolicantinformation. E-34 REV 02/16 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) = o sq. ft. □ ■ Total proposed newly created or replaced impervious area (B) = sq. ft. Percent impervious area created or replaced (B/A)*100 = % If you answered "yes", the structural BMPs required for PDP apply only to the creation or replacement of impervious surface and not the entire development. Go to step 5, check the first box stating "My project is a PDP ... " and complete applicant information. If you answered "no," the structural BM P's required for PDP apply to the entire development. Go to step 5, check the check the first box stating "My project is a PDP ... " and complete applicant information. STEPS CHECK THE APPROPRIATE BOX AND COMPLETE APPLICANT INFORMATION * My project is a PDP and must comply with PDP stormwater requirements of the BMP Manual. I understand I must prepare a Storm Water Quality Management Plan (SWQMP) for submittal at time of application. My project is a 'STANDARD PROJECT' OR EXEMPT from PDP and must only comply with 'STANDARD PROJECT' stormwater requirements of the BMP Manual. As part of these requirements, I will submit a "Standard Project Requirement Checklist Form E-36' and incorporate low impact development strategies throughout my project. Note: For projects that are close to meeting the PDP threshold, staff may require detailed impervious area calculations and exhibits to verify if 'STANDARD PROJECT' stormwater requirements apply. 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: Mr. Pino Vitti Applicant Title: Trustee Applicant Signature: Date: .. * Environmentally Sens1t1ve Areas include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies 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 City U OJ se n'Y YES City Concurrence: □ By: Date: Project ID: NO □ SITE INFORMATION CHECKLIST Project Summary Information Proiect Name Trails End Development Project ID CT04-14A Project Address Donna Drive, Carlsbad California Assessor's Parcel Number(s) (APN(s)) 156-090-41-00 Project Watershed (Hydrologic Unit) Carlsbad 904.21 Parcel Area 2.79 Acres ( 121,532 Square Feet) Existing Impervious Area (subset of Parcel Area) 0 Acres ( 0 Square Feet) Area to be disturbed by the project (Project Area) 2.79 Acres ( 121,532 Square Feet) Project Proposed Impervious Area (subset of Project Area) 1.34 Acres ( 58,510 Square Feet) Project Proposed Pervious Area (subset of Project Area) 1.45 Acres ( 63,022 Square Feet) Note: Proposed Impervious Area+ Proposed Pervious Area= Area to be Disturbed by the Project. This mav be less than the Parcel Area. E-34 REV 02/16 Description of Existing Site Condition and Drainage Patterns Current Status of the Site (select all that apply): Existing development Previously graded but not built out Agricultural or other non-impervious use ✓ 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: The site is an infill project and has never been developed previously. The site has characterized by natural vegetation and has no impervious surfaces. Underlying Soil belongs to Hydrologic Soil Group (select all that apply): NRCS Type A ✓ NRCS Type B NRCS Type C ✓ NRCS Type D Approximate Depth to Groundwater (GW): GW Depth < 5 feet 5 feet < GW Depth < 1 0 feet 1 0 feet < GW Depth < 20 feet ✓ GW Depth > 20 feet Existing Natural Hydrologic Features (select all that apply): Watercourses Seeps Springs Wetlands ✓ None Description/ Additional Information: 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]: E-34 The Trails End project site comprises approximately 2.79 acres and is located at the northwestern corner of Carlsbad Village Drive and Donna Drive, in the City of Carlsbad, California. The project is located approximately 0.46 miles west of the Intersection of El Camino Real and Carlsbad Village Drive. The project site is located approximately 0.75 miles southeast of the Buena Vista Lagoon. The site is located on the hillside of an undeveloped lot which slopes to west towards an open space area being densely covered with eucalyptus trees. The project site is covered with low ground cover type vegetation throughout and trees border the north and east sides of the property. There are no known historic sources of contamination on site. No known drainage structures are located on the property. The project site slopes steeply from the northeastern property line in a westerly direction. The elevation of the project site ranges from 186' to 253' feet above mean sea level (msl). Surface drainage at the site currently flows to the west, towards an open space area dense with eucalyptus trees then onto Hosp Way where the City drainage system intercepts the street flow. Stormwater is conveyed through surface runoff. Stormwater discharges, from the site, are not considered direct discharges, as defined by the State Water Board. Existing site topography, drainage patterns, and stormwater conveyance systems are shown on the Grading Plans. The site accepts no off site runoff from the adjacent roadways or adjoining properties. Drainage runoff ultimately reaches the Pacific Ocean via the Buena Vista Lagoon. Surface runoff from the site drains northwesterly from the site to an inlet on Hosp Way and is then conveyed to the Buena Vista Lagoon by the City storm drainage system. Surface runoff from this project travels approximately 2.5 miles downstream of the project before entering the Ocean. REV 02/16 Description of Proposed Site Development and Drainage Patterns Project Description/ Proposed Land Use and/or Activities: The proposed site is planned to be developed into (7) residential duplex buildings, each have 2 separate residences, for a total number of 14 residences. The proposed projects land use is consistent with the surrounding development and will not adversely impact the adjoining lands or the character of the neighborhood. List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): As with any residential development, the project will include impervious surfaces. Impervious surfaces will include; roofs, driveways, parking areas, streets, patios and hard landscaping. The increase in runoff as a function ofthe new impervious surfaces will be mitigated by a retention basin. List/describe proposed pervious features of the project (e.g., landscape areas): The project will include several types of pervious surfaces within the design. The pervious surfaces include; landscaping, grass areas, bio retention Basin, permeable pavers and planting areas. Does the project include grading and changes to site topography? ✓ Yes No Description/ Additional Information: Considering the site has never been graded before, the site will require considerable re- contouring to make the site developable for the land use plan. Although, every effort has been made to reduce the earthwork, the site will require approximately 22,000 cubic yards of fill be implement the design presented. Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)? ✓ Yes No Description/ Additional Information: As shown on the plan, several new drainage systems have been included in the designs which play an important role in controlling surface runoff. The facilities include; Catch Basins, area yard drains, storm drainage pipe, perforated underdrain pipes, headwalls, rip rap energy dissipaters, spillways and a bio-filtration basin. All of these systems work in conjunction to control and discharge flows in a manner most similar to the existing condition. Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply): ✓ On-site storm drain inlets ✓ Interior floor drains and elevator shaft sump pumps Interior parking garages ✓ Need for future indoor & structural pest control ✓ Landscape/Outdoor Pesticide Use ✓ Pools, spas, ponds, decorative fountains, and other water features Food service ✓ Refuse areas Industrial processes Outdoor storage of equipment or materials Vehicle and Equipment Cleaning Vehicle/Equipment Repair and Maintenance Fuel Dispensing Areas Loading Docks ✓ Fire Sprinkler Test Water ✓ Miscellaneous Drain or Wash Water ✓ Plazas, sidewalks, and parking lots E-34 REV 02/16 Identification of Receiving Water Pollutants of Concern Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): Surfa ce runoff draining from the site is discharged in a controlled fashion into a storm drain on Monroe Stre et approximately 1 mile upstream of the Buena Vista Lagoon. Runoff then travels an additional 1.5 miles within t he Lagoon before reaching the Pacific Ocean. 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 Buena Vista Creek/ 904.21 ~ediment Toxicity. Source Unknown; Selenium Needed Buena Vista Lagoon/ 904.21 Indicator Bacteria, Nutrients, Needed c,...,..i;..,,..,.,...,...,..._ ·inn/C:,il♦ ... t-inn .. · •-· <:.n,,r,..,.. Pacific Ocean Shoreline, Buena Vista Creek HA/ Indicator Bacteria. Nonpoint/Point Source Needed an, J1 Identification of Project Site Pollutants Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see BMP DesiQn Manual Aooendix B.6): Also a Receiving Not Applicable to Anticipated from the Water Pollutant of Pollutant the Project Site Project Site Concern X NA Sediment X NA Nutrients X NA Heavy Metals X NA OrQanic Compounds X NA Trash & Debris Oxygen Demanding X NA Substances X NA Oil & Grease X Bacteria & Viruses X NA Pesticides Hydromodification Management Requirements Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? Yes, hydromodification management flow control structural BMPs required. No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayment's, 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 embayment's, or the Pacific Ocean. ✓ No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides. Description/ Additional Information (to be provided if a 'No' answer has been selected above): Since the project is exempt from hydromodification, the critical coarse sediment is not an issue for this project site. Critical Coarse Sediment Yield Areas* *This Section only required if hydromodification management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? Yes No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite 6.2.2 Downstream Systems Sensitivity to Coarse Sediment 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps If optional analyses were performed, what is the final result? No critical coarse sediment yield areas to be protected based on verification of GLUs onsite Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 8 of the SWQMP. Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit. Discussion/ Additional Information: E-34 REV 02/16 Flow Control for Post-Project Runoff* *This Section only required if hydromodification management requirements apply List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1 ). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit. N/A, 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. Has a geomorphic assessment been performed for the receiving channel(s)? No, the low flow threshold is 0.102 (default low flow threshold) Yes, the result is the low flow threshold is 0.102 Yes, the result is the low flow threshold is 0.302 Yes, the result is the low flow threshold is 0.502 If a geomorphic assessment has been performed, provide title, date, and preparer: Discussion/ Additional Information: (optional) N/A, 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. Other Site Requirements and Constraints When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or City codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements. N/A City of Carlsbad ....... Zoning Ordinance City of Carlsbad ....... Design Guidelines City of Carlsbad ....... Grading and Drainage Ordinance City of Carlsbad ....... Engineering Standards Optional Additional Information or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed. N/A E-34 REV 02/16 c ·cityof Carlsbad Project Name: Trials End Developme nt Project ID:CT04-1A STANDARD PROJECT REQUIREMENT CHECKLIST E-36 Project Information DWG No. or Building Permit No.: 481 -1A Source Control BMPs Development Services Land Development Engineering 16'.35 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 for information to implement source control BMPs shown in this checklist. Answer each category below pursuant to thefollowing. • "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/justificat ion 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~ustification may be provided. Source Control Requirement Applied? SC-1 Prevention of Illicit Discharges into the MS4 i'XYes) No I N/A Discussiowiustification if SC-1 not implemented: - Discharges from site are controlled by BMP's preventing illicit discharges to the MS4. - SC-2 Storm Drain Stenciling or Signage [XYes 1 No I N/A Discussion/justification if SC-2 not implemented: - Drop Inlets will include stenciling and or placards indicating surface runoff drains to the Ocean. SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind Yes I No (xN/A~) Dispersal Discussion/justification if SC-3 not implemented: No post development storage of material is proposed. E-36 Page 1 of 4 Revised 03/16 Source Control Requirement (continued) Aoolied? SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and Yes No (I XN~ Wind Dispersal Discussion/justification if SC-4 not implemented: No post development outdoor work areas are proposed. SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal {"xYe~ Discussion/justification if SC-5 not implemented: - SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below and identify additional BMPs. (See Table in Appendix E.1 of BMP Manual for guidance). D On-site storm drain inlets .... x Yes ' D Interior floor drains and elevator shaft sump pumps 1~X yes:::, D Interior parking garages 1::XNo:1 D Need for future indoor & structural pest control 4..-X Yes-: D Landscape/Outdoor Pesticide Use .... XYes ~~ D Pools, spas, ponds, decorative fountains, and other water features 4 X No= D Food service _4 .... XNo-.... D Refuse areas r .._XYes ' D Industrial processes C XNoJ D Outdoor storage of equipment or materials 4 A. No DVehicle and Equipment Cleaning 4 XNo ~ D Vehicle/Equipment Repair and Maintenance 1...-X No::: D Fuel Dispensing Areas 4 XNo ~ DLoading Docks ◄..-X No-..... D Fire Sprinkler Test Water ,...X Yes~, D Miscellaneous Drain or Wash Water :::x Yes > D Plazas, sidewalks, and parking lots ,...x Yes~, For "Yes" answers, identify the additional BMP per Appendix E.1 . Provide justification for "No" a,·--· __ This is a residential project with no common interior parking structure. Site Design BMPs All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual 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. Source Control Requirement I -Aoolied? SD-1 Maintain Natural Drainage Pathways and Hydrologic Features tr X Yes l No I NIA Discussion/justification if SD-1 not implemented: ..... .J - SD-2 Conserve Natural Areas, Soils, and Vegetation I Yes (I X No ) IN/A Discussion/justification if SD-2 not implemented: ---- Considering the development plan and existing slopes across the site, the entire site will be regraded to accommodate the development plan. No significant trees or vegetation was observed on site. - SD-3 Minimize Impervious Area Cl X Yes l No IN/A Discussion/justification if SD-3 not implemented: ----- - SD-4 Minimize Soil Compaction I Yes l X No ) NIA Discussion/justification if SD-4 not implemented: ....... ~ -As the site will be completely regraded, soil compaction of import soils will be required. Unfortunately, no native areas will remain undisturbed. - SD-5 Impervious Area Dispersion I Yes(I X No) INIA Discussion/justification if SD-5 not implemented: ..... .J - E-36 Revised 03/16 Source Control Requirement (continued) I -Applied? SD-6 Runoff Collection (x Yes) No IN/A Discussion/justification if SD-6 not implemented: - - SD-7 Landscaping with Native or Drought Tolerant Species (XYes ) No I NIA Discussion/justification if SD-7 not implemented: - - SD-8 Harvesting and Using Precipitation I Yes l(X No l)NIA Discussion/justification if SD-8 not implemented: - Total rain barrel volume is less than 0.25 DCV and also the landscape areas are not greater than 30 percent of the project footprint (per required rain barrel in BMP manual). See Form 1-7 for calculation. 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. The pollution control measures and structural BMP's have been implemented on site. The proposed Bio-filtration Pond will treat onsite runoff. This systems and other infiltration BMP's such as pervious concrete pavers have also been used to infiltrate storm runoff. Hydromodification is exempt for this project therefore flow Control BMP is not required. The bio-filtration basin has a high rating for removal of all likely pollutants from storm water. E-36 Revised 03/16 [Continued from previous page -This page is reserved for continuation of description of general strategy for structural BMP implementation at the site.] Structural BMP Summary Information [Copy this page as needed to provide information for each individual proposed structural BMP] Structural BMP ID No. DWG 481-1A Sheet No. 4 Type of structural BMP: Retention by harvest and use (HU-1) Retention by infiltration basin (IN F-1) Retention by bioretention (INF-2) Retention by permeable pavement (INF-3) Partial retention by biofiltration with partial retention (PR-1) ✓ Biofiltration (BF-1) Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) Detention pond or vault for hydromodification management Other (describe in discussion section below) Purpose: ✓ Pollutant control only Hydromodification control only Combined pollutant control and hydromodification control Pre-treatment/forebay for another structural BMP Other (describe in discussion section below) Discussion (as needed): IMP #1 E-36 Revised 03/16 ATTACHMENT 1 BACKUPFORPDPPOLLUTANTCONTROLBMPS 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 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. ✓ Included ✓ Included on OMA Exhibit in Attachment 1 a Included as Attachment 1 b, separate from OMA Exhibit ✓ Included J Not included because the entire project will use infiltration BMPs ✓ Included J Not included because the entire project will use harvest and use BMPs Attachment 1 e Pollutant Control BMP Design ✓ Included Worksheets / Calculations (Required) Refer to Appendices B and E of the BMP Design Manual for structural pollutant control BMP design guidelines Appendix I: Forms and Checklists Use this checklist to ensure the required information has been included on the OMA Exhibit: The OMA Exhibit must identify: ✓ Underlying hydrologic soil group ✓ Approximate depth to groundwater ✓ Existing natural hydrologic features (watercourses, seeps, springs, wetlands) ✓ Critical coarse sediment yield areas to be protected (if present). "See Course Sediment Exhibit." ✓ Existing topography and impervious areas ✓ Existing and proposed site drainage network and connections to drainage off site ✓ 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) 1-2 I I I ~J ,. ---. I -"! r. I ',--.., / I }'' -i//l, I: ) I/ I , I I I , I , . \ \ ( I \ \ I I ) I ' I I ' I \ I ! 12'x12' /j AREA DRAINS I TYPICAL 7 \ ( \ \ I , I \ ', \ . ' I \ \ \ \ \ i ! \ \ I \ \ ' \ I\ \ \ \ ' ' \ \ \ \ I ,. , ' · .. , \. ".. \, \ " ' ' ' \, . ~--. ' ' ·, •1 ------...... " ... -... ' ---' ----......'"'~ ) .... '\'"·' < :, . ( I . \ \'\\ I_'.\ ·,,_ \ \ \ \ \ \ ' ' 1' \ \ \ ,., . \ \ ' .j \ \ I \ \ , \ I 1 \ % 1 1 \ I I I I I J ( I EMERGENCY SPILLWAY 't.__,_ "-.. -,.._ ' "-/ ~---,. ',I --~ /~ ~ ,-OUTLET STRUCTURE POC 1 IMP #1 =4,362 SF BASIN "+-_,,,. '-f-----.., ,, ~ ~;:.;.A.5::i--k-:,J _...,......,,.,:'::v::,._ "-J...'....:i:.::i-.__ -=::::::,~ """--· -"--~----_'( 1. THE PROJECT SITE IS UNDERLAIN WITH HYDROLOGIC SOIL GROUP 'B' 2::.:::: X 2. GROUND WATER WAS NOT OBSERVED OR FOUND DURING THE SOIL BORING OPERATION "-;,< / 12·x12· ::.._ .. :· . ' '·---. ..___ OMA#/ AND DMA#2 DISCHARGE DIRECTLY Ti AREA DRAINS -''~<··., -_ THE BMP BASIN OR IMP#/ AS SHOWN TYPICAL -~>~\ ~,< .. ' --•i , . I,'.;,' 1/'·-.,,;\1 ·-------~ '-\".:'. '-'-., \ \ ., /I I ,-/, !, :~ .---;------..._ _L ;f·'.,__j.. \-_;::--,..:. / -; !/-/>1 , I J :,.,, ;---.......\ ' ,' I / // ';;// ,/:' :/ I ',,: /1/l ,;/ ;<._x' I . ·Y 21> ', -:i-~ . ... '-'I ' /I / 10 P~\ C, \·-------~~ ~'i 1:~~, ~., I ·--~"\-/ -.-<: \ .; /" 'Z \ ,-~./. : 1\ ,}). ; \ +-'·"\ ;---t, a ~-t\4.1 ~, __ [___\ ~ , .. :5.3 -\, '-... ~ 12'x12" AREA DRAINS TYPICAL ,;,1 ',I 'I // // I ,1' i ·,, L,_ \ 11 " SWMP NO --1fi=2J. PARTY RESPONSIBLE FOR ~AINTENANCE: NAME PfY [AUil '< RE\IOCARI f TRIJSI ADDRESS 5505 CANCHA OE GOLF CONTACT OARJQ OE t \JCA RANCHO SANiA fE CA 92091 PHONE NO 8"-8 7""--0216 PLAN PREPARED BY: NAUE BRUCE TAIT. COJ2247 COMPANY MASSON k A$SPCIAir5 INC ADDRESS 200 E WA$HlljGTQN A\I[ 1200 fSGQNQIQO CA 02025 PHONE NO. 760-74]-'370 =- BMP NOTES. CERTflCA TION 05D /OSP 21Zl 5 1. THESE SMPS ARE MANDATORY TO 8[ INSTALLED PER UANUFACTURER'S RECOl,O.AENDATIONS OR THESE PLANS. 2 NO CHANGES TO THE PROPOSED 81.4PS ON THIS SHEET WITHOUT PRIOR APPROVAL FROU THE CITY ENGINEER J NO SUBSTITUTIONS 10 THE IAATERIAL OR TYPES OR PLANTING TYPES WITHOUT PRIOR APPROVAL FROU THE Cl TY ENGINEER. 4 NO OCCUPANCY Will BE GRANTED UNTIL THE CITY INSPECTION STAFF HAS INSPECTED THIS PRO.(CT fOR APPRC1'RIATE SUP CONSTRUCTION ANO INSTALLATION 5. RHER TO UAINTENANC[ AGREEMENT DOCUMENT. 6 SEE PRO.(CT SV.OUP FOR AOOlTIOHAL INFORUATION BMP TABLE SUP ID/ SUP TYPE SYIISDL CASOA NO. QUANTITY TREATMENT CONTROL 0 BIOflLTRATION TC-32 1,959 S.F HYDROMODIFICA TION & TREATMENT CONTROL N/A HYDROMODIFICA TION N/A LOW IMPACT DESIGN (LJD.) 0 PERI.IE ABLE t tttt: TC-10 2,825 SJ PAVEU[NT 0 GRASSPAVE2 ,;:;o;:;c TC-Jl 2.622 SJ SWART IRRIGATION N/A S0-12 N/A SOURCE CONTROL 0 :»tLNuL:i.· OJ HA "":~~O}'nUF;:!!19 .• S0-lJ 0) NEED FOR FUTURE [!] INDOOR/STRUCTURAL SC-41 PEST CONTROi. © LANDSCAPE/OUTDOOR w PESTIOOE USE: Pfl:OW)I SC-41 IMP ROOfTOP OR"1N TO 0 PER\4ClJS LANOSCAPE w sc-10 AREA, A'v'OIO US[ fS UtffOTECTEO METALS PLAZAS, SIOC\ltAU<S. ANO PARKING LOTS: ® S'NCEP REC.UL.ARLY, ~ SE-7 COLLECT OEBRIS, SC-4J COLL£CT WASTEWATER ANO DISCHARGE TO SANITARY S(lfll(R LEGEND BUILDING DRAINAGE AREA •1•1• O M A LANDSCAPE !::::::::::::! AC PAv(W[NT /' I PERI.IEA8L£ PAvttJ(NTS Etttttt8 GRASSPAVE2 t·~~~.~~~ SIORETEN TION 6A9N PR1VA T( STORU ()RAIN G---so- Fl.OW DIRECTION ~ RETAINING WALLS _,_ _______ ._ LOT LIN[ LOT# ROOF' DRAINS • DRAWING NO. SHEET NO.(S) NsPECTION * UAINTENANC£ * FREQUENCY FREQUENCY 481-lA 2 I.IONTHLY UONTHLY 481-IA 2 $El.It-ANNUALLY ANNUALLY 481-IA 2 SEUI-ANNUALL Y ANNUALLY 481-IL SEE LANDSCAPE UONTHLY AS-NEEDED PLANS 481-lA 2 SEUl-ANNUALL Y AS-NEEDED OMA EXHIBIT FOR TRAILS END CITY OF CARLSBAD, CA ~ lanning • Engineering • Surveying Solved. 200 E. Washington Ave .• Suite 200 ~ Escondido, CA 92025 MASSON & ASSOCIATES INC 0. 760.741.3570 F. 760.741.1786 W'W'W.mosson-assoc.com Appendix I: Forms and Checklists Harvest and Use Feasibility Checklist Form 1-7 1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the wet season? Toilet and urinal flushing ✓ Landscapeirrigation Other: 2. If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours. Guidance for planning level demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section B.3.2. [Provide a summary of calculations here] NA Flushing: 14 DU x 2.5 people per DU x 9.3 gallons/person x 36 hours/24 hours /day= 488 gallons, however, since practical method of utilizing stormwater for toilet flushing in private homes has not yet been developed, this demand i not included in the total demand for the site. Irrigation for Moderate Hydrozone: 1470 gallons per irrigated acre per 36 hours x .4 acres= 588 gallons Total Demand: 588 gallons 25%*2677=669 > 588 gallons 3. Calculate the DCV using worksheet B.2-1 . DCV = 2677 ( cubic feet) 3a. Is the 36 hour demand greater than or equal to the DCV? Yes I e Harvest and use appears to be feasible. Conduct more detailed evaluation and sizing calculations to confirm that DCV can be used at an adequate rate to meet drawdown criteria. 3b. ls the 36 hour demand greater than 0.25DCV but less than the full DCV? Yes / e Hal vest and use may be feasible. Conduct more detailed evaluation and sizing calculations to determine feasibility. Harvest and use may only be able to be used for a portion of the site, or (optionally) the storage may need to be upsized to meet long term capture targets while draining in longer than 36 hours. ls hatvest and use feasible based on fm1her evaluation? D Yes, refer to Appendix E to select and size harvest and use BMPs. ✓ No, select alternate BMPs. 1-3 3c. Is the 36 hour demand less tha~DCV? ~ Harvest and use is considered to be infeasibl February 26, C . . f I fil . F 'b'li C d' . Form 1-8 ategonzat10n o n 1 tratton east 1 ty on 1t10n Part 1-Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes No X Onsite testing using the inverse auger hole, or "Porchet" method evaluated infiltration rates of 0.25, 0.33, and 0.42 inches per hour to formational soils that would remain subsequent to remedial grading onsite. It should also be noted that any artificial fill, created through removal/recompaction of onsite souls would likely possess an infiltration rate below the 0.5 inch/hour threshold. See GSI report dated June21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendi..x C.2. Provide basis: X asins located within 10 feet of any residential structure or settlement sensitive improvement (walls, pavements, etc.) an adversely affect the performance of the improvement by, 1. Facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structure generally involves the removal and ecompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the evelopment of a shallow "perched" water table, which can be anticipated to migrate laterally, beneath the structure(s). Planned utilities in the vicinity would act as "french drains" and also be adversely affected. Adjacent, ffsite slopes are generally steeper than 3: 1 (horizontal to vertical) and would be subject to an increased potential for instability due to the lateral migration of water from a potential infiltration area located up gradient. See GSI report ated June 21, 2016 for other related di scussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Criteria 3 Appendix I: Forms and Checklists Form 1-8 Page 2 of 4 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 to this Screening Question must be based on a comprehensive evaluation of the factors presented in .Appendix C.3. Yes No X Provide basis: This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in .Appendix C.3. X Provide basis: [fhis is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet existing grades onsite. Significant drainage courses do not appear to present onsite, and/or would be truncated by the existing Hosp Way, located downslope and offsite to the west of the site and should not be adversely affected by infiltration from a site of ~his size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Part 1 Result * If all answers to rows 1 -4 are "Yes" a full infiltration design is potentially feasible. The feasibility screening catego1y is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 Proceed to Part 2 *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by .Agency /Jurisdictions to substantiate findings 1-5 February 26, Form 1-8 Page 3 of 4 Part 2 -Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount he physically feasible without any negative consequences that cannot he reasonably mitigated? Criteria 5 Screening Question Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes X No Site specific infiltration testing evaluated infiltration rates of 0.25, 0.33 and 0.42 inches per hour for onsite native soils. However, it should be noted that any artificial fill, created through removal/ recompaction of onsite soils would likely possess a further reduced infiltration rate, and basins located within 10 feet of a residential stmcture, utility trench, or other improvement, would be adversely affected. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Cao Infiltration in any appreciable quantity he allowed without increasing risk of geotechoical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in AppendiJ, C.2. Provide basis: Please see Discussion Note at the End of this Form I-8 X No. Basin located within 10 feet of any residential structure can adversely affect the performance of the structures foundation system by, 1. Facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structure generally involves the removal and recompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the development of a shallow "perched" water able, which can be anticipated to migrate laterally, beneath the structure(s), or offsite adjacent property. Planned utilities in the vicinity would act as "french drains" and also be adversely affected. Adjacent, offsite slopes are generally steeper than 3:1 (horizontal to vertical) and would be subject to an increased potential for instability due to he lateral migration of water from a potential infiltration area located up gradient. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. Criteria 7 Form 1-8 Page 4 of 4 Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Yes No X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question must be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: X rI'his is a hillside development. The site currently drains offsite and no runoff appears to be retained onsite. Significant drainage courses do not appear to present onsite, and/or would be truncated by the existing Hosp Way, located downslope and offsite to the west of the site and should not be adversely affected by infiltration from a site of ~his size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 1-4 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. No Infiltration *To be completed usmg gathered site 111format1on and best professional judgment cons1der111g the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by Agency /Jurisdictions to substantiate findings Discussion Note: This bio-filtration site was logically placed at the lowest corner of the site. This is also the location of the connection of the proposed sewer to the existing sewer in the neighboring property. Due to the topography it is necessary to construct a berm to contain the stormwater during treatment. About 11 feet from the toe of this berm is an existing home. These factors combined, result in increased risk of geotechnical hazards such as slope stability, utilities and moisture intrusion to the adjacent downhill home. These factors cannot be acceptably mitigated to an acceptable level, since mitigation would require lining around 70% of the bio-filtration basin and even this lining would not guarantee complete elimination of infiltration in unacceptable areas. 100% impervious liner is therefore recommended. 1 85th percentile 24-hr storm depth 2 Area tributary to BMP (s) 3 Area Weighted runoff factor 4 Rain Barrels volume reduction 5 Street trees volume reduction 6 Calculator DCV = 3630 x C x d x A -TCV -RCV I Area Weighted runoff factor = = d= 0.600 inches A= 2.41 acres C= 0.62 unitless TCV = 0 cubic-feet RCV= 0 cubic-feet DCV= 3261.4 cubic-feet ( ( 0.9*( 56400)+0.3*( 16908+23558+8488) )/( 105332)) 0.62 1-9 February 26, ~ .,..., ... ••• ·-•=n- Jing DCV after nnplementmg retention BMPs 3261.4 cubic-feet Partial Retention 2 Infiltration rate from Worksheet D.5-1 if partial infiltration is feasible 0 3 Allowable drawdown time for aggregate storage below the underdrain 36 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 5 Aggregate pore space 0.4 6 Required depth of gravel below the underdrain 11,ine 4/ Line 5] 0 7 Asswned surface area of the bioftltration Bl'vIP 2600 8 l\1edia retained pore space 0.1 9 Volwne retained by BMP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7 390 10 DCV th<'lt requires bioftltration [Line 1 -Line 9] 2871.4 BMP Parameters 11 Surface Ponding [6 inch minimum, 12 inch m aximum] ** 24 12 Media Thickness [18 inches minimwn] 18 13 Aggregate Storage above underdrain invert (12 inches typical) -use O inches for 12 sizing if the aggregate is not over the entire bottom surface area 14 l\1edia available pore space 0.2 15 l'viedia filtration rate to be used for sizing 5 Baseline Calculations 16 Allowable Routing T ime for sizing 6 17 D epth filtered during stonn [ Line 15 x Line 16] 30 18 Depth of Detention Storage 32.4 [Line 11 + (Line 12 x Line 14) + (Line13 x Line 5)] 19 Total Depth Treated 11,ine 17 + Line 18] 62.4 Option 1-Biofilter 1.5 times the DCV 20 Required bioftltered volume (1.5 x Line 10] 4307 21 Required Footprint [Line 20/ Line 19] x 12 828 Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) Volume [0.75 x Line 1 OJ 2154 23 Required Footprint [Line 22/ Line 18] x 12 798 Footprint of the BMP 24 Area draining to the Bl\1P 105332 25 Ad justed Rw10ff Factor for drainage area (Refer to A ppendix B.1 and B.2) 0 .62 26 Minimwn BMP Footprint [Line 24 x Line 25 x 0.03] 1959 27 Footprint of the BMP = Maximwn(Minimum(Line 21, Line 23), Line 26) 1959 Note: Line 7 is u sed to estimate the amount of volume retained by the BM1'. Update assumed surfaae area in Line 7 until its equivalent to the required biofiltration footprint (eith er Line 21 or Line 23) * See Form 1-8 ** Side slope mostly< 10% in/hr. hours inches in/in inches sq-ft in/in cubic-feet cubic-feet inches inches inches in/in in/hr. hours inches inches inches cubic-feet sq-ft cubic-feet sq-ft sq-ft sq-ft sq-ft SITE San Diego County 85 th Percentile lsopluvials Legend -85th PERCENTILE ISOPLUVIAL [:J INCORPORATED CITY NOTE: The 85th percentile is a 24 hour rainfall total. It represetns a value such that 85% of the observed 24 hour rainfall totals will be less than that value. I-February 26, ' " 12·x12· AREA DRAJNS TYPICAL ' '· EMERGENCY SPILLWAY ' " ' ' ' ' ' ~-- ....... ' ' IMP #1 •2,013 SF BASIN 12·x12· AREA DRAINS TYPICAL ...... ' ~ ·{.:~<i-:;;_,_ '.:'~/·, ..... ·, ·~:.:.:~---,._,.J )' 1 Tl£ PROJECT SITE IS UfC>ER..AN Wl71-I HYDROLOGIC SOL GROt.P ·s· 2. a:IO(N:) WATER WAS NOT~ OR FOUfC> DI.ff.JG Tl£ SOL BORl«1 OPERATION .;..,_-;;,;:J·;·'-:!:,j-;__/ .... ' -~./ ;:~/- '':,'.'. ::.. ' ' ,__ ,. 7, " .·;,_::, .. ·--~~---··· , '.'.~: ,, -·~ , ... •.,:. ,,-,·;i;. ' ., 12·x12· AREA DRAJNS I TYPICAL ,~ ,' ., 1,,· ;'' ,~-'' / Q~:,' /' h:' /1 ,' , ~1/' '~(j-,, ...... _,,,_ I •• ., ' ,, ·-...... •· :",, . ~Y __ ,,/'' :./ -·::;--·,: /~1 --, -9~~< / ·:--·-.... ;',, I I ,;~ / ':< I :..,·-•,. /~ ,' / ..... ; ','. ·•' ~1/ . ~/ ··<.. ;·;-/',. , / (o , , ·• .. _,, ,{.-,' ,, , ,•, ,' .,. ~.,·" .,/ ,"' ;, •• _____ :,, ~,,, ,' ,✓-..-. -~ . I , ·, .... , ... , . ~-, I • ' "-(J_:'>-iv. --,-,,.y . _., I / '/,:., t ., ·' ,, ~·.::-· DMA#I AJC) DMAl2 DISCHARCE DfiECTI..Y Tl Tl£ 81.F BASIN OR W#1 AS SHOWN \, ... ;· -~ .... ~ , .. )1/ - , ".,~' /. . :'/~ 20-10 / // 40 60 '\,. \ \ A top---, 5"/HR SOIL OF GRAVEL BIOFIL T~ TION AREA CROSS SECTION (TYP) NOT TO SCALE IMP Hm"" fuoi1 Hriaer He Abot Acop(FT2) To!AI Ag(FT2) Volume (Fl) (Fl) I 2.0 1.5 Trails End 85th .e_ercentile 24-hr storm depth Area tributary_to Bfv1P (s} Area Wei_g_hted runoff factor Rain Barrels volume reduction Street trees volume reduction Calculator DCV = 3630x Cx dx A}-TCV-RCV (Fl) (Fl) (FT2) (CF) 1 l.ll 1959 6GO 2,031 2.565 d= 0.600 inches A= 2.41 acres C= 0.62 unitless TCV= 0 cubic-feet RCV= 0 cubic-feet DCV= 3261.4 cubic-feet ((0.9*(56400)-+-0,3*(16908+23558+8488))/(105332)} 0.62 LEGEND BUILDING DRAINAGE AAfA •1•1• DMA LANDSCAPE ~:::::::::::! AC PA',£MENT P£RMEABlE PA"91ENTS GRASSPA~ BKR TRA TION BASIN ..... PRIVATE STOOM DRAIN 13--so- FlOW DIRECTION ~ RETAINING WALLS -----.. -··-·-LOT LINE LOT# ROOF DRAINS • .Alanning .. Engineering .. Surveying Salved. 200 E. Washington Ave .. Suite 200 ~ Escondido. CA 92025 MASSON & ASSOCI ATES , INC. 0, 760.741.3570 F. 760.741.1786 www.mosson-assoc.com ~I crtt.9Ls,91n I~ BMP SITE PLAN MAP FOR TRAILS END DCORD COPY -. -1=:1 I -:.,. I /' / " ,./ " " / " " " " / GRASSPAVE2 ' ' ' ' ' ' ' ----- I / II I I \ / / / I ,/ \ \ \ \ \ \ \ \ \ ~ \\ A 01 02 0 p \\"- '\. \ '----j) / \ ~, '\ ,,;1' ' \ (/ ' 1/ ,, ;/ ~'I 1/ , \ ~ / '-, '/ " '· ;1 '"' ,,< /, V / / ............ \ / ~, II Ill ~ I I '" ~ SOURCE CONTROL BMPs MARK INLETS WITH THE WORDS: "NO DUMPING! FLOWS TO BAY" NEED FOR FUTURE INDOOR/STRUCTURAL PEST CONTROL LANDSCAPE/OUTDOOR PESTICIDE USE: PROVIDE IMP ROOFTOP ANO EQUIPMENT: CONNECT CONDENSATE DRAIN TO SANITARY SEWER, PROVIDE ROOFING AND/OR SECONDARY CONTAINMENT TO EQUIPMENT, AVOID USE OF UNPROTECTED METALS PLAZAS, SIOEWLAKS, ANO PARKING LOTS: SWEEP REGULARY, COLLECT DEBRIS, COLLECT WASH WATER ANO DISCHARGE TO SANITARY SEWER LEGEND BUILDING I I LANDSCAPE ~-·····:--··1 AC PAVEMENT PERMEABLE PAVEMENTS GRASSPAVE2 ~;-q; BIOFIL TRA TION BASIN -PRIVATE STORM DRAIN 0--SD - FLOW DIRECTION ~ RETAINING WALLS ------ROOf DRAINS • 20 10 0 ..N 20 SCALE IN FEET GRAPHIC SCALE 1·-20· 40 60 SOURCE CONTROL EXHIBIT FOR TRAILS END CITY OF CARLSBAD, CA .. lanning • Engineering • Surveying Solved. 200 E. Washington Ave., Suite 200 ~ Escondido, CA 92025 MASSON & ASSOCIATES, INC, 0. 760.741.3570 F. 760,741.1786 www .masson-assoc.com " '-.. " " .•... -· ._'-.'-.. ·" 12·x12· AREA DRAINS TYPICAL / / /· /' '- •, ·, '- "' '- " '- --.. :;, '- ·;..~ ·,, ,-,,. ... " '-'- ~ -~·-. ·,_ CONCRETE DITCH r ---, ~-=, ., 12·x12· AREA DRAINS TYPICAL ·--.__ _____ ,........ ~-'."<' -Li .,c·· / ., ,, ' ''t '<-~#s. .. \'t-~-~.J... ~- ',' ~-~-...... ,('-:. .... ~ ---"i- > ·, . '·· . ~-::::-:":\~ . ,.'.i.' ;//,", 1.✓ ~/, / ,1 ,t. ~, ,,. , ,'.'v . ~ , //'-,, ,;, ' j 20 10 20 SCALE IN FEET GRAPHIC SCALE 1•--,n• \,\ ,'. .. \~; ~:. ·::. t~ \~(···-P-- ;~}~: ·.t:, .... ?;_ .., ' 40 60 .N LEGEND SWMP N0.-16=.2.1 BUILDING I I PARTY RESPONSIBLE FOR MAINTENANCE: NAME PfY FAMILY BfWCARI E TRUST LANDSCAPE 1::::::::::::1 AIIORESS 5505 CANOjA DE G(X,f CONTACT PABIP PE I I/CA RANOiO SANTA ft, CA 92091 PHONE NO. 1\58-755-02)6 AC PA\IEJ.tENT PLAN PREP AREO BY: PERMEABLE PAVEMENTS NAME BRUCE TAIT, CQ.32247 ~ GRASSPAVE2 BIOFlL TRA TION BASIN PRIVATE STORM DRAIN 0--so- FLOW DIRECTION ~ RETAINING WAUS ---------ROOF DRAINS • ,·_,., BMP ll #I BMP nPE N/A SYMBOl C().IPAHY MASWN ,t ASSOClATFS INC ADORESS 200 E WA211NCIOO A.\f l2QO ESCOQOO CA 92025 ~ENO. 76P:74J-J570 BMP NOTES: CERTIFlCAllON OSl /052 21715 1. THESE BMPS ARE MANDATORY TO BE INSTAl.1£D PER MANUFACTURER'S RECOMMENDATIONS OR THESE PUNS. 2. NO OiANCES TO THE PRCl'OSEO BMPS ON THIS SHEIT "11HOUT PRIOR APPROVAL FROM lHE OTY EN<lNEER. J. NO SUBSTITUTIONS TO THE MATrR1AL OR TYPES OR PUNllNC TYPES "1THOUT PRIOR APPROVAL FROM THE ClTY OONEIR . 4. NO OCOJPANCY 'MU OC GRANTED UNTIL THE OTY INSPECTION STAff HAS INSPECTED THIS PRMCT FOR APPROPRIATE BMP CONSTRUCTION ANO INSTALLATION. 5. REFER TO MAINTENANCE AGRWIENT OOOJMENT. 6. SEE PRMCT S'!lllMP FOR ADDITIONAL INFORMATION. BMP TABLE CASOA NO. QUANTITY ORA"1NG NO. I SHEET NO.(S) TC-32 2.013 S.F. 481-lA INSPECTION * FREQUENCY MONTHLY MAINTENANCE * FREQUENCY MONTHLY & TREATMENT CONTROL ' ' ~"\ ""I HYDROMODIFICA TION I ' , ~.< N/A I I I I I I I LOW IMPACT DESIGN f!-.1.D.} 0 0 PERIIEA8l.E PAVEMENT GRASSPA>O SMART l<l<IG,\TION SOURCE CONTROL 0 (v N/A 0 - [I] - TC-10 TC-31 S0-12 I S!l-13 I I SC-41 2,825 S.F. 48HA SEMI-ANNUALLY I ANNUALLY 2,622 S.F. 481-lA SEMI-ANNUALLY I ANNUALLY N/A 481-IL MONTHLY AS-NEEDED J EA I 481-lA I 2 I SEMI-ANNUAU.Y I AS-NEED!D 12·x12· AREA DRAINS TYPICAL G) 0 RWTOP DRAIN TO PU<\10.JSLANOSCAPE lvl£A Al'OO USE Of UNPROTEClID M£TAlS [!] I - CD I SC-41 SC-10 I I I I I lj' . , /j \ ® /.:-·-... ,.-- PlA2AS. SllEWAU<S. ANO PARKING LOTS: S'IIIEEP REQJ..AAt.Y, ca.LECT llOlRls. CQ.l£CT WASTrWA TER AIIJ O&><AR<JE TO SANITARY SE1lfR @] I ~; ( ( I SE-7 SC-43 ...__..,...__..,._,.,___,...__.., Rf\lSED BASIN SZE AND HATCHING 8/19/19 RO OAT£ ....... REVISION DESCRIPTION 011-IER APPROVAL I ~ "' 1i5 I I I I I~ ,;; 1~ I~ LE:J I CI TY OF CARLSBAD II SHEETS I ENCINEERING OEPARTMENT 1 SINGlE SHEET BMP PLAN TRAILS END RECORD COPY I PRo.ECT NO. I CT04-14A DATE ....... I DRAWING NO. I CTY APPROVAL. INITIAL DATE 481-1SW 12·x12· AREA DRAINS TYPICAL ', ,' "--. " ~ . '-. . >-- . " / "--"--"'7-- ·,-..... ,·, ... _., .. -., ·_:,,_ ::::f'.~_,._,,.h -...:-.:::-.(-''v/ .¥ 1 Tl£ PROJECT SITE IS IAC>ERI...AN Wl7H HYDROLOGIC SOI. GROUP •a• 2. GRO<H) WATER WAS NOT~ OR FOI.JltC DURIJG Tl£ SOL BORING OPERATION DMAII AJC) DMAl2 DISCHARGE DfiECTL Y Tl 11-E BMP BASIJ OR MPft AS SHOWN -✓< I / ,:/ / '\' \ ,; \ ,·. .,/'-., ~;r,. \;; , ,, ' ',;,,:·, ,,;;.._ ,:_~/ ,, {; / 12·x12· 1> AREA DRAINS TYPICAL ' 60 ' ~-.:• '·/. ,, , , ,,, -¢';;/I '(,' //':'.· 4·,,. ,,,,/_, ·,, Sl'IMP NO . ..J.li=2J PARTY RESPONSIBLE FOR MAINTENANCE: NAME PEY fAN!I Y R[\offAR! E TRUST AOORESS 5505 CANCHA DE GOLF CONTACT PABIQ PE I UCA RANOiO SANTA fE CA 92091 PHONE NO. 1!58-755--0216 PLAN PREPARED BY: NAME BRUCE TAIT, C032247 COMPANY MAW & A.SSQQATFS INC AOORESS 20Q E WASHINGTON A.W: ,ZOO ESCQNPfOO CA 92025 PHONE NO. 760:-Z!i-JSZQ ll<iRAm BMP NOTES: CERTiflCATI~ 050/0SP 21715 1. 111ES£ BMPS All£ MANDATORY TO BE INSTALLED PER MANUFACTURER'S RECOMMENO,OiONS OR 111ES£ PLANS. 2. NO CHANGES TO 111E PROPOSED BMPS ON 1111S SHEET Y!1110UT PRIOR APPROVAL FROM lliE OTY E!IGINEER. 3. NO SUBSTITUTIONS TO 111E MATERIAL OR TYPES OR PLANTING TYPES \1111liOUT PRIOR APPROVAL FROM 111E OTY ENGINEER. 4. NO OCCUPANCY \ll1U. BE GRANTED UNTIL 111E OTY INSPECTION STAFF HAS INSPECTED 1111S PRO.ECT FOR APPROPRIATE BMP CONSTRUCTION AND INSTALLATION. 5. REFER TO MAINTENANCE AGREEME!IT DOCUMENT. 6. S£E PRQ..ECT SWllMP FOR AOOITIONAL INFORMATION. BMP TABLE BMP 10 f BMP T'IPE SYMBOL CASOA NO. QUANTITY DRAYING NO. TREATMENT CONTROL 0 BIOFILTRATION ~ TC-32 2,013 S.F. 481-IA HYDROMODIFICATION & TREATMENT CONTROL N/A HYDROMODIFICA TION N/A LOW IMPACT DESIGN (l.l.D.} 0 PERMEABU: ~ttttt TC-10 2.a2S s.F. 481-IA PA-.0,ENT 0 GRASSPA\£2 ~ TC-31 2,622 S.F. 481-IA SMART """""llON N/A SD-12 N/A 481-IL SOURCE CONTROL ® ,,~ 0 SD-13 3 EA 481-IA ...... :~~ ... ~M~G. .• ,. 0 NEED FOR F\J1\JR£ [TI IHOoa</SlRl!CMW. SC-41 PEST COITRa. © LANOSCAPE/OOlDOa< 0 PESllQOC US£: PROWl! SC-41 ,., ROCFTCP DRAIN TO © PER'aOUS lANOSCAPE 0 SC-10 ""-A AYOIO US£ ~ UNPROT[Clll) M£TALS PlAZAS. SIOEW,IIJ(S, 00 PARKNG LOTS: @ S'OEEPRECULARLY, ~ S[-7 crurcr OEl!RlS. SC-43 cwrcr WASltWA TtR NID DISQ-IARGE TO SANITARYSEIIO! AS ~ 8/19/1!, I 1£REBY ASSIJ1L RESPfflSlll CHARGE f"CR DESIGN OiANGES TO lHIS DRAWING LEGEND BUILDING SltEIT NO.(S) INSPECTION * FREOOE!ICY 2 MONTHLY 2 SEM!-ANNUAllY 2 SEMI-ANNUAllY SEE LANDSCAPE MONTHLY PlANS 2 SEMi-ANNUAllY MAINITNANCE * FREOOE!ICY MON111LY ANNUAllY ANNUALLY AS-NE£00l AS-NEEOED DRAINAGE AREA • ; -I • OMA ,------------------1 l,INOSCAPE I· ........... I AC PA-.0,ENT PERMEABLE P.,,o,ENTS GRASSPA\£2 BIDRE1ENTION BASIN PRIVATE STORM DRAIN flOW DIRECTION RETAINING WAI.LS LOT LINE ROOF ORAJNS G---so- --"7 LOT# • OMA EXHIBIT FOR TRAILS END CITY OF CARLSBAD, CA .. lanning "' Engineering "'Surveying Solved. 200 E. Washington Ave .. Suite 200 ~ Escondido. CA 92025 0 . 760.741.3570 M As s O N F. 760.741.1786 & ASSOCIATES . INC . www.masson"ossoc.com Attachment Sequence Attachment 2a Attachment 2b Attachment 2c Attachment 2d ATTACHMENT 2 BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES [This is the cover sheet for Attachment 2.] Indicate which Items are Included behind this cover sheet: None required since this site will be exempt from hydromodification requirements. Contents Checklist Hydromodification Management Included Exhibit (Required) See Hydromodification Management Exhibit Checklist on the back of this ~ttachment cover sheet. Management of Critical Coarse Exhibit showing project drainage Sediment Yield Areas (WMAA Exhibit boundaries marked on WMAA is required, additional analyses are Critical Coarse Sediment Yield optional) ~rea Map (Required) See Section 6.2 of the BMP Design Optional analyses for Critical Coarse Manual. Sediment Yield Area Determination 6.2.1 Verification of Geomorphic Landscape Units Onsite 6.2.2 Downstream Systems Sensitivity to Coarse Sediment 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite Geomorphic Assessment of Receiving Not performed Channels (Optional) Included See Section 6.3.4 of the BMP Design Manual. Flow Control Facility Design and Included Structural BMP Drawdown Calculations (Required) See Chapter 6 and Appendix G of the BMP Desiqn Manual Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit: Not required since this site will be exempt from hydromodification requirements. The Hydromodification Management Exhibit must identify: Underlying hydrologic soil group Approximate depth to groundwater Existing natural hydrologic features ( watercourses, seeps, springs, wetlands) Critical coarse sediment yield areas to be protected (if present) Existing topography Existing and proposed site drainage network and connections to drainage off site Proposed grading Proposed impervious features Proposed design features and surface treatments used to minimize imperviousness Point(s) of Compliance (POC) for Hydromodification Management Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) I-February 26, ATTACHMENT 3 Structural BMP Maintenance Information Use this checklist to ensure the required information has been included in the Structural BMP Maintenance Information Attachment: Preliminary Design/Planning/CEQA level submittal: Attachment 3 must identify: ► Typical maintenance indicators and actions for proposed structural BMP(s) based on Section 7.7 of the BMP Design Manual Final Design level submittal: Attachment 3 must identify: ► Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s). o The indicators of required maintenance include the failure of any of the BMP's. Failure of the BMP could include clogging of an inlet as indicated by failure to drain or slow draining of the bio Basin. The Basin should drain in a 72 hour period and be free debris. ► How to access the structural BMP(s) to inspect and perform maintenance. o Maintenance of the BMP can easily be accessed from the projects common open space. Permeable pavers have been provided on the access pathway for equipment should it be necessary to maintain the bio-filtration BMP. Access to clean out the pipe can be done via removable catch basin grate inlet. ► 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) o The access corridor to the Structural BMP's has been overlain with concrete pavers, insuring permanent access to the Bio Retention Basin, headwall and spillway. Appendix I: Forms and Checklists ► Manufacturer and part number for proprietary parts of structural BMP(s) when applicable. o No specific proprietary parts or part numbers ► 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.) o Please see inspection and fact sheets on the following pages. ► Recommended equipment to perform maintenance. o Routine maintenance can be accomplished with hand tools. Should major maintenance (such as replacement of amended soil or gravel) be required, it is anticipated that a small backhoe will be needed. ► When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management. o No special training or certification is required. I-February 26, E.18 BF-1 Biofiltration Location: 43"1 Street and Logan Avenue, san Diego, California Description Append.i.-.: E: B lP Design Fact Sheets 0 Applicable Perfonnance Standard Pollutant Control Primary Benefits Treatment Volume Reduction (Incidental) Peak Flow Attenuation (Optional) Biofiltration (Biorctcntion with undcrdrain) facilities arc vegetated surface water systems that filter water through ,•egetation, and soil or engineered media prior to discharge via w1derdrain or overflow to the downstream conveyance system. Biorctention with underdrain facilities are commonly incorporated into the site ·within parking lot landscaping, along roadsides, and in open spaces. Because these types of facilities have limited or no infiltration, they arc typically designed to prm•ide enough hydraulic head to move flows through the underdrain connection to the storm drain system. Treatment is achieved through filtration, sedimentation, sorption, biochemical processes and plant uptake. Typical bioretention with underdrain components include: • Inflow distribution mechanisms (e.g, perimeter flow spreader or filter strips) • Energy dissipation mechanism for concentrated inflows (e.g., splash blocks or riprap) • Shallow surface ponding for capnued flows • Side slope and basin bottom vegetation selected based on expected climate and ponding depth • on-floating mulch layer (Optional) • Media layer (planting mi.'< 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 aggregate storage layer • Aggregate storage layer with underdrain(s) E-91 Febmary 26, 2016 Appendix I: Forms and Checkli sts • lm~trr..ea tc 4,~, o, u,~2ctcd 1utxw ~s t the bottom of the i'Anb · • •c-rt . lt\l UC' ... . . ( ••*.,,,,. , .· .... ~-... "•'. ~ : ..... ~ -92 F~ ru ty • 201 I-February 26, Appendi.-. E: BMP Design Fact Sheets Typical plan and Section view of a Biofiltration BMP Design Adaptations for Project Goals Biofiltration Treatment BMP for storm water pollutant control. The system is lined or un-liued to pronde incidental infiltration, and an underdrain is pro\i.ded at the bottom to carry away filtered mnoff. Tilis configuration is considered to provide biofiltration treatment \i.a flow through the media layer. Storage provided abo1;-e the tmderdra.ii1 within surface ponding, media, and aggregate storage is considered included in the biofiltration treatment volume. Saturated storage \\ithi.n the aggregate storage layer can be added to this design by raising the tmderdra.ii1 above the bottom of the aggreg-ate storage layer or ,>ia an internal weir stmcture designed to mrunta.ii1 a specific water level elevation. Integrated storm water flow control and pollutant control configuration. TI1e system can be designed to prO\ide flow rate and duration control by primarily providing increased surface ponding and/or having a deeper aggreg-ate storage layer 11bove the tu1derdra.ii1. Tius ,vill allow for significant detention storage, which can be controlled via inclusion of ru1 outlet structure at the do,\ nstream end of the underdrain. Design Criteria and Considerations Bioretention with underdra:in must meet the following design criteria. Deviations from the below criteria may be approved at the discretion of Cotlllty staff if it is determined to be appropriate: Siting and Design □ □ Placement obserxes geotechnical recommendations reg-arding potential hazards (e.g., slope stability, landslides, liquefaction zones) and setbacks (e.g., slopes, foundations, utilities). An impermeable liner or other hydraulic restriction layer is included if site constra.iim indicate that infiltration or lateral flows should not be allowed. E-93 Intent/Rationale Must not negatively impact existing site geotec.lulical concerns. Lining prevents storm water from impacting groundwater and/ or sensitive environmental or geotecluucal features. Incident.'ll infiltration, "hen allowable, can aid in pollutant removal and grotmdwater recharge. Febmary 26, 2016 Siri.ng and Design □ □ Contributing tributary area must be :S S acres (::5 1 acre preferred). Finish grade of the facility is ::5 2%. Surfllce Ponding □ □ □ Surface ponding is limited to a 24-hour d.rawdown time. Surface ponding depth is =:'. 6 and ::5 12 inches. A mini.Jmun of 2 i.J1ches of fceeboard is provided. E-94 I- Appendix I: Forms and Checklists Appendix E: BMP Design Fact Sheets Intent/Rationale Bigger B:MPs require additional design features for proper performance. Contributing tributary area greater than S acres may be allowed at the discretion of Com1ty staff if the following conditions are met 1) incorporate design features (e.g. flow spceade.rs) to minimize short circuiting of flows in the B!-.IP and 2) incorporate additional design features requested by County staff for proper performance of the regional B~·IP. Rattee surfaces reduce erosion and channelization within the facility. Surface ponding limited to 24 hour foe plant health. Surface ponding d.rawdown time greater than 24-hours but less than 96 hours may be allowed at the discretion of County staff if certified by a landscape architect or agronomist. Surface ponding capacity lowers subsurface storage requirements. Deep surface ponding raises safety cone.ems. Surface ponding depth greater than 12 inches (for additional pollutant control or surface outlet stmcmres or flow-control orifices) may be allowed at the discretion of Com1ty staff if the following conditions are met 1) surface ponding depth dra\, down time is less than 24 hours; and 2) safety issues and fencing requirements are considered (typically ponding greater than 18" will requi.ce a fence and/or flatter side slopes) and 3) potential for elevated dogging risk is considered. Freeboard provides room for head o,cr overflow strncn1res and miniulizes risk of uncontrolled surface discharge. Febmary 26, 2016 February 26, SUiface Ponding □ Side slopes are stabilized ,vi.th vegetation and are= 3H:1V or shallower. Vegetation Appendi.x E: BMP Design Fact Sheets Gentler side slopes are safer, less prone to erosion, able to establish vegetation more quickly and easier to maintain. PL'Ulti.ngs are suitable for tl1e climate and Plants suited to t11e clim.'lte and ponding O expected ponding depth. A plant list to aid in depth are more likely to survive. selection crui be found in Appendi.., E.20. An irrig-ation system with a connection to water D supply should be pro°\'ided as needed. Mulch (Mandatory) □ A minimum of 3 inches of well-aged, shredded h.'lrdwood mulch that has been stockpiled or stored for at least 12 montl1s is provided. M edisz Lsz yer □ Medi.a maintains a min.im1un 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 ti.n1e; tl1e initial filtration rote should not exceed 12 inches per hone. E-95 Seasonal irrigation might be needed to keep plants hc.'lltl1y. i\folch \\'Ill suppress weeds and maintain moisnire for plant growth. Aging mulch kills patl1ogens 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. The initial rate should be higher than loug term target rate to accow1t for clogging over ti.me. However an excessively high initial rate can ha,re a neg-ative .impact on treatment performance, therefore an upper ti.nut is needed. Febmary 26, 2016 Media Layer 0 □ □ Media is a minimum 18 inches deep, meeting either of these two media specifications: Gty of San Diego Storm Water Standards Appendi.'i: F (Febru.'U}· 2016, tulless superseded by more recent edition) m: County of San Diego Low Impact De, clopment Handbook: Appendix G -Biorctention Soil Specification Qune 2014, unless superseded by more recent edition). AlternativelJ , for proprietary designs and custom media mi.'i:cs not meeting the media specifications contained in the 2016 City Storm Water Standards or County LID 1\Ianual, the media meets the pollutant treatment performance criteria in Section F. l. 1\ledia surface area is 3% of contributing area times adjusted mnoff factor or greater. Unless demonstrnted that the Bi\[P surface area can be smaller than 3%. \'\1here receiving waters a.re impaired or have a TMDL for nutrients, the system is designed \\rith 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. E-96 I- Appendi x I: Forms and Checklists Appendix E: BM P Design Fact Sheets A deep media layer provides additional filtration and supports plants \vi.th deeper roots. Standard specifications must be followed. For non-standard or proprietary designs, compliance with F.1 ensures that adequate treatment performance will be provided. Greater surface area to tributary area ratios: a) ma.'i:imizes volume retention as required by the 1S4 Permit and b) decrease loading rates per square foot and therefore increase longevity. Adjusted mnoff factor is to account for site design BMPs implemented upstream oftbe BMP (such as rain barrels, impenrious area dispersion, etc.). Refer to Appendix B.2 guidance. Use Worksheet B.5-1 Linc 26 to estimate the minimum surface area required per this criteria. Potential for pollutant export is partl a function of media composition; media design must minimize potential for export of nutrients, particuL'l.rly where recciv.ing waters a.re 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. Febmary 26, 2016 February 26, Filter Course Layer □ □ Filter course is washed and free of fines. Filter course calculations assessing suitability for particle migration prevention have bee!l completed. Aggregate Storage Layer □ □ Class 2 Permeable per Caltrans specification 68- 1.025 is recommended for the storage laye.r. \\ ashed, open-graded cmshed rock may be used, however a 4-6 .incl1 washed pea gravel filter course layer at the top of the crushed rock is required. The depth of aggregate provided (12-inch typical) and storage layer configuration is adequate for pro,riding conveyance for unde.rdra.in flows to the outlet stmcture. Iatlow, Uaderdrain, and Outtlow Structures □ □ □ □ □ Inflow, underdrains and outflow strucmres a.re accessible for inspection and maintenance. Inflow velocities a.re 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 ,,ride, have a 4-6 i.nd1 reveal (drop) and an apron and energy dissipation as needed. Underdrai.n outlet elevation should be a mi.ni.n11.1m of 3 inches above tl1e bottom elevation of the aggregate storage layer. :Minimum underdra.in diameter is 6 inches. E-97 Appendix E: BMP Design Fact Sheets \\ ashing aggregate will help eliminate fines that could clog the facility and impede infiltration. 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. \\ ashing aggregate w-ill help eliminate fines that could clog the aggregate storage layer void spaces or subgrnde. Proper storage layer configuration and underdrain placement will minimize facility drawdotw-i1 time. Mai.ntenru1ce will prevent clogging and ensure proper operation of the flow control stmctures. 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 minima.I separation from subgrade or the liner lessens tl1e risk of fines entering tl1e underdrai.n and can improve hydraulic performance by allowing perforations to remain imblocked. Smaller d.ian1eter underdra.i.t1s are prone to clogging. Febma.ry 26, 2016 Appendix I: Forms and C hecklists Appendi.-. E: BMP Design Fact Sheets In.iow, Un derdrain, and Out.Dow Structures D D D Underdrains are made of slotted, PVC pipe conforming to ASTiv1 D 3034 or equivalent or conugated, HDPE pipe conforming to AASHTO 252M or equivalent. An underdra.in cleanout with a minimum 6-inch diameter and lockable cap is placed e,rery 250 to 300 feet as required based on tu1derdrain length. 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. Slotted tmderdrains prm,'ide greater intake capacity, clog resistant drainage, and reduced entrance velocity into the pipe, thereby reducing the chances of solids migration. Properly spaced deanouts will facilitate tu1derdrai.t1 maintenance. Planning for overflow lessens the risk of property damage due to flooding. Conceptual Design and Sizing Approach for Storm Water Pollutant Control Only To design bioretention with 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 tributru:y area, ma.'illnum 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. Use the sizing worksheet presented in Appendix B.5 to size biofiltration B:tv!Ps. 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 the manual 1. Verify that siting and design criteria have been met, including placement requirements, contributing tributary area, ma.'illnum 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 storage to reduce flow rates and durations to allowable limits. Flow rates and durations can be controlled from detention storage by altering outlet su·ucnue orifice size(s) and/or water control levels. Multi-level orifices can be E-98 Feb ruary 26, 2016 I-February 26, Appendi.x E: BMP Design Fact Sheets used within an outlet strncrure to control the full range of flows. 3. If bioretention with tuidcrdraiu cannot fully provide the flow rate and duration control required by tlus manual, an upstream or downstream stmcnu:e with sigiuficant storage volume such as ru1 undergrotuid vault can be used to provide remaining controls. 4. After bioretention with underdrain has been desigi1ed to meet flow control requirements, calculations must be completed to verify if stom1 water pollutant control requirements to treat the DCV ha,e been met. E-99 Febmary 26, 2016 Inspection and Maintenance Checklist BIO-FILTRATION Defect Conditions when maintenance is needed 1. Standing water I Water stands in the biofiltratlon swale between stonns and does not drain within 24 hours after rainfall. 2. Trash and debris I Trash and debris accumulated in the bioftltration swale and around the inlet 3. Sediment I Evkl~ce of accumulated sediment in the biofiltratlon swale. 4. Erosion ---I Channels have formed around inlets, there are areas of bare soil, or there is other evidence of erosion. 5. Vegetation I Vegetation is dead, diseased, or overgrown. 6. Mulch (if used) I Mulch is missing or patchy. Areas of bare earth are exposed or mulch layer is less th,in 1 inr.h•~ rl.-n 7. Inlet/outlet I Sediment or debris accumulations. 8. Miscellaneous I Any condition not covered above that needs attention for the bioflltration swale to function as designed. 9. Flow Control Structure I Water stands in the bioftltratlon swale between storms and does not drain Within 24 hours after rainfall. Appendix I: Forms and Checklists Permit no. ______________________ _ BMP location _____________________ _ Responsible party ____________________ _ Phone number ( , ________ Email ---------Responsible party address _________________ _ Date of inspection ____________________ _ Maintenance needed? Date and description of maintenance conducted• Results expected when maintenance is performed There should be no areas of standing water once inflow has ceased. Any of the following could apply: sediment or trash blockages removed, grade from head to foot of bioflltratlon area improved, media surface scarified, underdrains flushed in manner that does not cause an illegal discharge. Trash and debris removed from the biofiltration swale and disposed of properly. Material removed so that there is no clogging or blockage. Material is disposed of properly. Obstructions and sediment removed so that water flows freely and disperses throughout the bioflltration swale. Obstructions and sediment are disposed of properly. Vegetation is healthy and attractive. Grass is maintained at least 3 inches in height. All bare earth is covered, except mulch is kept 6 inches away from trunks of trees and shrubs. Mulch is even at ,. rl•nth nf 1 inr.h•" Inlet/outlet is dear of sediment and debris and allows water to flow freely. The design specifications are met. Maintenance will prevent dogging . TABLE 7-3. Maintenance Indicators and Actions for Vegetated BMPs Typical Maintenance Indicator(s) M . A • r V d BMP atntenance cttons ior egetate s Accumulation of sediment, litter, or debris Poor vegetation establishment Overgrown vegetation Erosion due to concentrated irrigation flow Erosion due to concentrated storm water runoff flow Standing water in vegetated swales Standing water ill biofiltration with partial biofiltration areas, or planter boxes for longer following a storm event* bioreten tion, retention, or flow-through than 96 hours Obstructed inlet or outlet structure 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 than the design height of the vegetation per original plans when applicable (e.g. a vegetated swale may require a minimum vegetation height). Repair/re-seed/re-plant eroded areas and adjust the irrigation system. Repair/re-seed/re-plant eroded areas, and make appropriate corrective measures such as adding erosion control blankets, adding stone at flow entry points, or minor re-grading to restore proper drainage according to the original plan. If the issue is not corrected by restoring the BMP to the original plan and grade, The County must be contacted prior to any additional repairs or reconstruction. Make appropriate corrective measures such as adjusting irrigation system, removing obstructions of debris or invasive vegetation, loosening or replacing top soil to allow for better infiltration, or minor re-grading for proper drainage. If the issue is not corrected by restoring the B:MP to the original plan and grade, County staff in the \v'atershed Protection Program must be contacted prior to any additional repairs or reconstruction. Make appropriate corrective measures such as adjusting irrigation system, removing obstructions of debris or invasive vegetation, clearing underdrains (where applicable), or repairing/replacing clogged or compacted soils. Clear obst:1.uctions. Damage to structural components such as Repair or replace as applicable. weirs, inlet or outlet structures *These BMPs typically include a surface ponding layer as part of their function which may take 96 hours to drain following a storm event. Geotechnical • Geologic • Coastal • Environmental 5741 Palmer Way • Carlsbad, California92010 • (760) 438-3155 • FAX (760) 931-0915 • www.geosoilsinc.com June 21, 2016 Pacifica Real Estate Services, Inc. 5505 Cancha de Golf Rancho Santa Fe, California 92091 Attention: Ms. Andrea Raynal W.O. 6635-A1-SC Subject: Storm Water Infiltration Rate Evaluation, Trails End Development, Carlsbad, San Diego County, California Dear Ms. Raynal: In accordance with your request and authorization, and in response to City plan check comments (Esgil, 2015), GeoSoils, Inc. (GSI) has prepared the following supplementto our geotechnical update (GSI, 2016), regarding storm water infiltration at the subject site. GSl's scope of services included a review of the referenced reports/plans (see Appendix A), onsite infiltration testing, engineering and geologic analysis, and preparation of this report. Unless specifically superceded in the text of this report, the conclusions and recommendations presented in GSI (2013, 2014, and 2016) are considered valid and applicable with respect to the subject site, and should be properly incorporated into the design and construction phases of site development. STORM WATER TREATMENT AND HYDROMODIFICATION MANAGEMENT Infiltration Feasibility In accordance with the BMP Design Manual (County, 2016), the infiltration feasibility for this site was evaluated. An evaluation of the soils hydraulic conductivity, or (K) was performed in accordance with the Porchet, or inverse auger hole method (Van Hoorm, 1979; USBR, 1984). Based on the testing performed, K values of 0.25 inches/hour (Test Hole #1), 0.33 inches/hour (Test Hole #2), and 0.42 inches/hour (Test Hole #3) were evaluated. These values are generally below the recommended feasibility threshold (0.50 inches per hour) per the EPA (Clar, et al., 2004), and the County (County, 2016) for full infiltration. It should be noted that a review of the United States Department of Agriculture database (USDA; 1973, 2015) indicates surficial soils were evaluated with infiltration rates on the order of 0.57 to 1.98 inches/hour; however, these rates are evaluated for surficial soils that would be removed and exported, or recompacted during mass grading, and as such, are not considered representative of "as-built" site conditions, or representative of rates for the relatively denser and less permeable "formational" soils at depth, that were evaluated as part of this report. Based on our review and engineering analysis, full infiltration, is not feasible. Partial infiltration may be feasible for areas of undisturbed soil, located no closer than 1 O feet from any structure. For hydromodification structures located within 1 O feet of a residential structure, storm water treatment and hydromodification management should be designed for no infiltration. An additional discussion of infiltration feasibility is presented in Appendix 8, which contains a Categorization of infiltration feasibility condition, worksheet C.41, provided by the City (2016). It should be noted that the infiltration rates evaluated are for undisturbed, native soils. Infiltration rates for compacted fills will be substantially less. Compacted fills are considered as belonging to Hydrologic soil Group "D" (no infiltration). Onsite Infiltration-Runoff Retention Systems General design criteria regarding the use of onsite infiltration-runoff retention systems (OIRRS) are presented below. Should onsite infiltration-runoff retention systems (OIRRS) be planned for Best Management Practices (BMP's) or Low Impact Development (LID) principles for the project, some guidelines should/must be followed in the planning, design, and construction of such systems. Such facilities, if improperly designed or implemented without consideration of the geotechnical aspects of site conditions, can contribute to flooding, saturation of bearing materials beneath site improvements, slope instability, and possible concentration and contribution of pollutants into the groundwater or storm drain and/or utility trench systems. A key factor in these systems is the infiltration rate (often referred to as the percolation rate) which can be ascribed to, or determined for, the earth materials within which these systems are installed. Additionally, the infiltration rate of the designed system (which may include gravel, sand , mulch/topsoil, or other amendments, etc.) will need to be considered. The project infiltration testing is very site specific, any changes to the location of the proposed OIRRS and/or estimated size of the OIRRS, may require additional infiltration testing. Locally, relatively impermeable formations include the underlying formational (Santiago) bedrock, which is anticipated to have relatively very low vertical infiltration rate. Some of the methods which are utilized for onsite infiltration include percolation basins, dry wells, bio-swale/bio-retention, permeable pavers/pavement, infiltration trenches, filter boxes and subsurface infiltration galleries/chambers. Some of these systems are constructed using native and import soils, perforated piping, and filter fabrics while others Pacifica Real Estate Services, Inc. Trails End, Carlsbad File:e:\wp12\6600\6635a1 .gua GeoSoils, Inc. W.O. 6635-A1 -SC June 21 , 2016 Page 3 employ structural components such as stormwater infiltration chambers and filters/separators. Every site will have characteristics which should lend themselves to one or more of these methods; but, not every site is suitable for OIRRS. In practice, OIRRS are usually initially designed by the project design civil engineer. Selection of methods should include (but should not be limited to) review by licensed professionals including the geotechnical engineer, hydrogeologist, engineering geologist, project civil engineer, landscape architect, environmental professional, and industrial hygienist. Applicable governing agency requirements should be reviewed and included in design considerations. The following geotechnical guidelines should be considered when designing onsite infiltration-runoff retention systems: • It is not good engineering practice to allow water to saturate soils, especially near slopes or improvements; however, the controlling agency/authority is now requiring this for OIRRS purposes on many projects. • Wherever possible, infiltration systems should not be installed within ±50 feet of the tops of slopes steeper than 15 percent or within H/3 from the tops of slopes (where H equals the height of slope). • Wherever possible, infiltrations systems should not be placed within a distance of H/2 from the toes of slopes (where H equals the height of slope). • Wherever possible, infiltration systems should not be installed within 1 O feet of a residential structure. • The landscape architect should be notified of the location of the proposed OIRRS. If landscaping is proposed within the OIRRS, consideration should be given to the type of vegetation chosen and their potential effect upon subsurface improvements (i.e., some trees/shrubs will have an effect on subsurface improvements with their extensive root systems). Over-watering landscape areas above, or adjacent to, the proposed OIRRS could adversely affect performance of the system. Soil chemical amendment could alter soil chemistry, which may affect soil corrosion and permeability. • Areas adjacent to, or within, the OIRRS that are subject to inundation should be properly protected against scouring, undermining, and erosion, in accordance with the recommendations of the design engineer. • If subsurface infiltration galleries/chambers are proposed, the appropriate size, depth interval, and ultimate placement of the detention/infiltration system should be evaluated by the design engineer, and be of sufficient width/depth to achieve optimum performance, based on the infiltration rates provided. In addition, proper debris filter systems will need to be utilized for the infiltration galleries/chambers. Debris filter systems will need to be self cleaning and periodically and regularly maintained on a regular basis. Provisions for the regular and periodic maintenance Pacifica Real Estate Services, Inc. Trails End, Carlsbad File:e:\wp12\6600\6635a1 .gua GeoSoils, Inc. W.O. 6635-A1 -SC June 21, 2016 Page 4 of any debris filter system is recommended and this condition should be disclosed to all interested/affected parties. • Where infiltration systems are located within setback areas noted above, impermeable liners and subdrains should be used along the bottom of bioretention swales/basins located within the influence of slopes and structures. Impermeable liners used in conjunction with bioretention basins should consist of a 30-mil polyvinyl chloride (PVC) membrane that is covered by a minimum of 12 inches of clean soil, free from rocks and debris, with a maximum 4:1 (h:v) slope inclination, or flatter, and meets the following minimum specifications: Specific Gravity (ASTM D792): 1.2 (g/cc, min.); Tensile (ASTM D882): 73 (lb/in-width, min); Elongation at Break (ASTM D882): 380 (%, min); Modulus (ASTM D882): 32 (lb/in-width, min.); and Tear Strength (ASTM D1004): 8 (lb/in, min); Seam Shear Strength (ASTM D882) 58.4 (lb/in, min); Seam Peel Strength (ASTM D882) 15 (lb/in, min). Final project plans (grading, precise grading, foundation, retaining wall, landscaping, etc.), should be reviewed by this office prior to construction, so that construction is in accordance with the conclusions and recommendations of this report. Based on our review, supplemental recommendations and/or further geotechnical studies may be warranted. It should be noted that structural and landscape plans were not available for review at this time. LIMITATIONS The conclusions and recommendations presented herein are professional opinions. These opinions have been derived in accordance with current standards of practice, and no warranty is express or implied. Standards of practice are subject to change with time. GSI assumes no responsibility or liability for work or testing performed by others, or their inaction; or work performed when GSI is not requested to be onsite, to evaluate if our recommendations have been properly implemented. Use of this report constitutes an agreement and consent by the user to all the limitations outlined above, notwithstanding any other agreements that may be in place. In addition, this report may be subject to review by the controlling authorities. Thus, this report brings to completion our scope of services for this portion of the project. Pacifica Real Estate Services, Inc. Trails End, Carlsbad File:e:\wp12\6600\6635a1 .gua GeoSoils, line. W.O. 6635-A1-SC June 21, 2016 Page 5 The opportunity to be of service is greatly appreciated. If you have any questions concerning this report, or if we may be of further assistance, please do not hesitate to contact any of the undersigned. Respectfully submitted, GeoSoils, Inc. /6~ Robert G. Crisman Engineering Geologist, CEG 1934 RGC/DWS/JPF/jh Attachments: Appendix A -References Appendix B -Infiltration Worksheet and Test Data Plate 1 -Infiltration Test Location Map Distribution: {2) Addressee Pacifica Real Estate Services, Inc. Trails End, Carlsbad File:e:\wp12\6600\6635a1 .gua GeoSoils, Inc. W.O. 6635-A1 -SC June 21, 2016 Page 6 APPENDIX A REFERENCES American Concrete Institute, 2011, Building code requirements for structural concrete (ACI 318-11), an ACI standard and commentary: reported by ACI Committee 318; Adopted May 24, published August. American Society of Civil Engineers, 201 O, Minimum design loads for buildings and other structures, ASCE Standard ASCE/SEI 7-10. Blake, Thomas F., 2000, EQFAULT, A computer program for the estimation of peak horizontal acceleration from 3-D fault sources; Windows 95/98 version. Building News, 1995, CAL-OSHA, State of California, Construction Safety Orders, Title 8, Chapter 4, Subchapter 4, amended October 1. California Building Standards Commission, 2013a, California Building Code, California Code of Regulations, Title 24, Part 2, Volume 2 of 2, Based on the 2012 International Building Code, 2013 California Historical Building Code, Title 24, Part 8; 2013 California Existing Building Code, Title 24, Part 1 O. __ , 2013b, 2013 California green building standards code of regulations, Title 24, Part 11, dated July. Cao, T., Bryant, W.A., Rowshandel, B., Branum, D., and Willis, C.J., 2003, The revised 2002 California probalistic seismic hazard maps, dated June, http://www.conversation.ca.gov/cgs/rghm/psha/fault_parameters/pdf/documents /2002 _ca_ hazardmaps.pdf Esgil Corporation, 2015, Plan check for: Seven new duplexes, N.W. corner of Carlsbad Village Drive & Donna Dr., Plan Chk. No. PC13-0072, dated November 13. GeoSoils, Inc., 2016, Geotechnical update and plan review, Trails End development, Carlsbad, California, W.O. 6635-A1-SC, dated June 6. __ , 2014, Geotechnical discussion and review, retaining wall drainage and permeable pavement design/construction, proposed Trails End Development, Northwest Corner of the Donna Drive and Carlsbad Village Drive Intersection, Carlsbad, San Diego County, California, W.O. 6635-A-SC, Dated March 20. __ , 2013, Geotechnical update evaluation, proposed Trails End Development, Northwest corner of the Donna Drive and Carlsbad Village Drive Intersection, Carlsbad, San Diego County, California, W.O. 6635-A-SC, dated November 27. __ , 2005, Geotechnical grading plan review, Trails End Development, northwest corner of the intersection of Donna Drive and Carlsbad Village Drive, Carlsbad, San Diego County, c ·alifornia, W.O. 3993-A1-SC.i dated August 29. GeoSoils, Inc. __ , 2003, Preliminary geotechnical evaluation, Trails End Development, Northwest corner of the intersection of Donna Drive and Carlsbad Village Drive, City of Carlsbad, San Diego County, W.O. 3993-A-SC, dated December 15. Masson & Associates, Inc., 2015, precise grading plans for: Trails End development, CT 04-14A, Sheets 1 through 5, Drawing 481-1A, Job No. 13136, Print Dated October 14. United States Geological Survey, 2014, U.S. Seismic design maps, earthquake hazards program, http://geohazards.usgs.gov/designmaps/us/application.php. Version 3.1.0, dated July. GeoSoils9 Inc. GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated Februa,y 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements W orksbeet C.4-1: Categorization of Infiltration Feasibility Condition Categorization of Infiltration Condition Worksheet 3.4-1 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: X Onsite testing using the inverse auger hole, or "Porchet" method evaluated infiltration rates of 0.25. 0.33, and 0.42 inches per hour for formational soils that would remain subsequent to remedial grading onsite. It should also be noted that any artificial fill, created through removal/recompaction of onsite soils would likely possess an infiltration rate below the 0.5 inch/hour threshold. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: X Basins located within 10 feet of any residential structure or settlement sensitive improvement (walls, pavements, etc.) can adversely affect the performance of the improvement by, 1. facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structures generally involves the removal and recompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the development of a shallow "perched" water table, which can be anticipated to migrate laterally, beneath the structure(s). Planned utilities in the vicinity would act as "trench drains" and also be adversely affected. Adjacent, offsite slopes are generally steeper than 3:1 (horizontal to vertical) and would be subject to an increased potential for instability due to the lateral migration of water from a potential infiltration area located up gradient. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. C-11 February 2016 GSI Appendix B. W.O. 6635-Al-SC. dated June 21, 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated Februa,y 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements 3 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensible evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Can Infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as a change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Significant drainage courses do not appear present onsite, and/or would be truncated by the existing Hosp Way, located downslope and offsite to the west of the site and should not be adversely affected by infiltration from a site of this size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 1 In the answers to rows 1-4 are "Yes" a full infiltration design is potentially feasible. The feasibility Result* screening category is Full Infiltration Ifany answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 proceed to part 2 * To be completed using gathered site information and best professional judgement considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by [City Engineer] to substantiate findings. C-12 February 2016 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated Feb111a1y 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements 5 Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and AppendixD. Provide basis: X Site specific infiltration testing evaluated infiltration rates of 0.25, 0.33, and 0.42 inches per hour for onsite native soils. However, it should be noted that any artificial fill, created through removal/recompaction of onsite soils would likely possess a further reduced infiltration rate, and basins located within 10 feet of a residential structure, utility trench, or other improvement, would be adversely affected. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 6 Can infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: X No. Basins located within 1 0 feet of any residential structure can adversely affect the performance of the structures foundation system by, 1. facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structures generally involves the removal and recompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the development of a shallow "perched" water table, which can be anticipated to migrate laterally, beneath the structure(s), or offsite onsite adjacent property. Planned utilities in the vicinity would potentially act as "french drains" and also be adversely affected. Adjacent, offsite slopes are generally steeper than 3:1 (horizontal to vertical) and would be subject to an increased potential for instability due to the lateral migration of water from a potential infiltration area located up gradient. See GSI report dated June 21, 2016 for other related discussions and references. C-13 February 2016 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated Februa,y 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 7 Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 8 Can infiltration be 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. Provide basis: X This is a hillside development. The site currently drains offsite and no runoff appears to be retained onsite. Significant drainage courses do not appear present on site, and/or would be truncated by the existing Hosp Way, located downslope and offsite to the west of the site and should not be adversely affected by infiltration from a site of this size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 2 If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The Result* feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. No Infiltration *Tobe completed using gathered site information and best professional judgement considering the definition ofMEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. C-14 February 2016 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BlYfP Desig11 Ma1111al, Sa11 Diego Regio11: Appe11dices, dated Febma,y 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements Worksheet C.4-l: Categorization of Infiltration Feasibility Condition Categorization of Infiltration Condition . . Worksheet 3.4-1 Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on X a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Onsite testing using the inverse auger hole, or "Porchet" method evaluated infiltration rates of 0.25. 0.33, and 0.42 inches per hour for formational soils that would remain subsequent to remedial grading onsite. It should also be noted that any artificial fill, created through removal/recompaction of onsite soils would likely possess an infiltration rate below the 0.5 inch/hour threshold. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotecbnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: X Basins located within 10 feet of any residential structure or settlement sensitive improvement (walls, pavements, etc.) can adversely affect the performance of the improvement by, 1. facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structures generally involves the removal and recompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the development of a shallow "perched" water table, which can be anticipated to migrate laterally, beneath the structure(s). Planned utilities in the vicinity would act as "trench drains" and also be adversely affected. Adjacent, offsite slopes are generally steeper than 3:1 (horizontal to vertical) and would be subject to an increased potential for instability due to the lateral migration of water from a potential infiltration area located up gradient. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. C-11 February 2016 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated February 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements 3 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensible evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as a change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Significant drainage courses do not appear present onsite, and/or would be truncated by the existing Hosp Way, located downslope and offsite to the west of the site and should not be adversely affected by infiltration from a site of this size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 1 Result* In the answers to rows 1-4 are ''Yes" a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 proceed to part 2 *Tobe completed using gathered site information and best professional judgement considering the definition ofMEP in the MS4 Permit. Additional testing and/or studies may be required by [City Engineer] to substantiate findings. C-12 February 2016 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 From "Model BAD' Design Manual, San Diego Region: Appendices, dated Feb111ary 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements 5 Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and AppendixD. Provide basis: X Site specific infiltration testing evaluated infiltration rates of 0.25, 0.33, and 0.42 inches per hour for onsite native soils. However, it should be noted that any artificial fill, created through removal/recompaction of onsite soils would likely possess a further reduced infiltration rate, and basins located within 1 o feet of a residential structure, utility trench, or other improvement, would be adversely affected. See GSI report dated June 21, 2016 for other related discussions and references. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 6 Can infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: X No. Basins located within 10 feet of any residential structure can adversely affect the performance of the structures foundation system by, 1. facilitating heave of expansive soil, 2. Increasing soil moisture transmission rates through concrete flooring, and 3. Increase the potential for a loss in bearing strength of soil, due to saturation. Mitigative grading for the support of structures generally involves the removal and recompaction of near surface soils. This is anticipated to create a permeability contrast, and the potential for the development of a shallow "perched" water table, which can be anticipated to migrate laterally, beneath the structure(s), or offsite onsite adjacent property. Planned utilities in the vicinity would potentially act as "trench drains" and also be adversely affected. Adjacent, offsite slopes are generally steeper than 3:1 (horizontal to vertical) and would be subject to an increased potential for instability due to the lateral migration of water from a potential infiltration area located up gradient. See GSI report dated June 21, 2016 for other related discussions and references. C-13 February 2016 GSI Appendix B. W.O. 6635-Al-SC. dated June 21. 2016 From "Model BMP Design Manual, San Diego Region: Appendices, dated February 2016 Appendix C: Geotechnical and Groundwater Investigation Requirements Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 7 Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: X This is a hillside development. Groundwater was evaluated at a depth of greater than 50 feet below existing grades onsite. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 8 Can infiltration be 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. Provide basis: X This is a hillside development. The site currently drains offsite and no runoff appears to be retained onsite. Significant drainage courses do not appear present onsite, and/or would be truncated by the existing Hosp Way, located downslope and offslte to the west of the site and should not be adversely affected by infiltration from a site of this size. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 2 If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The Result* feasibility screening category is _Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. No Infiltration *Tobe completed using gathered site information and best professional judgement considering the definition ofMEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. C-14 February 2016 • Geotechnical • Geologic • Environmental 5741 PalmerWay • Carlsbad, California92008 • (760)438-3155 • FAX(760)931-0915 INVERSED AUGER HOLE (PORCHET) METHOD -DATA SHEET PROJECT: Trails End, Santee DATE: June, 2016 CLIENT: Pacifica Real Estate Services WORK ORDER: 6635-A 1-SC HOLE NUMBER 1 uses SOIL CLASSIFICATION SM DEPTH (D') OF TEST HOLE (in) 42.25 inches HOLE DIAMETER (in) HOLE RADIUS (r) (in) 4.5 inches 2.25 inches INITIAL WATER LEVEL (in) 23.25 inches Time .6t (min) t (min) Ht (in) 9:41 0 0 23.25 10:06 25 25 29.33 10:27 20 45 31 .50 11 :55 28 73 32.50 11:28 33 106 33.75 K = 1.15 r tan a where tan a = [log (h0 + ½ r) -log (h1 + ½ r)] / t-t0 K = 0.25 inches/hour NOTES: ht (in) 19.0 12.92 10.75 9.75 8.50 relatively dense and cemented at 30 inches. Heavily burrowed from 0 to 18 inches ht+½ r 20.125 14.045 11.90 10.87 9.62 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 • Geotechnical • Geologic • Environmental 5741 Palmer Way • Carlsbad, California 92008 • (760)438-3155 • FAX(760)931-0915 INVERSED AUGER HOLE (PORCHET) METHOD -DATA SHEET PROJECT: Trails End, Santee DATE:June,2016 CLIENT: Pacifica Real Estate Services WORK ORDER: 6635-A 1-SC HOLE NUMBER 2 uses SOIL CLASSIFICATION SM DEPTH (D') OF TEST HOLE (in) 43 inches HOLE DIAMETER (in) HOLE RADIUS (r) (in) 4.5 inches 2.25 inches INITIAL WATER LEVEL (in) 24.25 inches Time ~t (min) t (min) Ht (in) 10:25 0 0 24.25 10:55 30 30 27.75 11 :30 35 65 29.50 12:00 30 95 31 .5 K = 1.15 r tan a where tan a = [log (h0 + ½ r) -log (h, + ½ r)J / t-t0 K = 0.33 inches/hour NOTES: relatively dense and cemented at 24 to 30 inches. ht (in) 18.75 15.25 13.50 11 .5 ht+½ r 19.87 16.37 14.62 12.62 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 • Geotechnical • Geologic • Environmental 5741PalmerWay • Carlsbad, California92008 • (760)438-3155 • FAX(760)931-0915 INVERSED AUGER HOLE (PORCHET) METHOD -DATA SHEET PROJECT: Trails End , Santee DATE:June,2016 CLIENT: Pacifica Real Estate Services WORK ORDER: 6635-A 1-SC HOLE NUMBER 3 uses SOIL CLASSIFICATION SM DEPTH (D') OF TEST HOLE (in) 47 inches HOLE DIAMETER (in) HOLE RADIUS (r) (in) 4.5 inches 2.25 inches INITIAL WATER LEVEL (in) 31.0 inches Time flt (min) t (min) 10:35 0 0 11 :00 30 30 11 :35 30 60 12:05 30 90 12:55 30 120 K = 1 .15 r tan a Ht (in) 31.0 34.50 36.25 38.25 40.0 where tan a = [log {h0 + ½ r) -log (h1 + ½ r)] / t-t0 K = 0.42 inches/hour NOTES: relatively dense and cemented at 30 inches. ht (in) 16.0 12.5 10.75 8.75 7.0 ht+½ r 17.12 13.62 11.87 9.87 8.12 GSI Appendix B, W.O. 6635-Al-SC, dated June 21, 2016 4(,3. Approximate location of infiltration test scale 1 inch equals 20 feet FORM 89/22 INFILTRATION TEST LOCATION MAP TRAILS END, CARLSBAD, CALIFORNIA DATE _6/_1_6 ___ .w.o. NO. 663s-A1-sc Geotechnical Engineering • Engineering Geology PLATE 1