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CT 14-04; MILES BUENA VISTA; STORM WATER QUALITY MANAGEMENT PLAN- SWQMP; 2017-01-13
CITY OF CARLSBAD PRIORITY DEVELOPMENT PROJECT (PDP) STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) 1, FOR •1~\L6S ~e:NA \/ISf.4 ROBERT MILES SUBDIVISION CT 14-04 1833 BUENA VISTA WAY SWQMP NO. 14-04 ENGINEER OF WORK: EXP 3-31-2019 PREPARED FOR: ROBERT MILES MILES PACIFIC LIMITED PARTNERSHIP 1833 BUENA VISTA WAY CARLSBAD, CA 92008 760-889-9011 PREPARED BY: bHA Inc ' 5115 AVENIDA ENCINAS, SUITE L CARLSBAD, CA 92008-4387 (760) 931-8700 DATE: JANUARY 13, 2017 WO. 452-1289-600 DATE . TABLE OF CONTENTS Certification Page Project Vicinity Map FORM E-34 Storm Water Standard Questionnaire Site Information FORM E-36 Standard Project Requirement Checklist Summary of PDP Structural BMPs Attachment 1: Backup for PDP Pollutant Control BMPs Attachment 1 a: OMA Exhibit Attachment 1 b: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment 1 c: Harvest and Use Feasibility Screening (when applicable) Attachment 1 d: Categorization of Infiltration Feasibility Condition (when applicable) Attachment 1 e: Pollutant Control BMP Design Worksheets I Calculations Attachment 2: Structural BMP Maintenance Thresholds and Actions Attachment 3: Single Sheet BMP (SSBMP) Exhibit Attachment 4: Geotechnical Reference 2 CERTIFICATION PAGE Project Name: Robert Miles Subdivision Project ID: CT 14-04/PUD 14-06/CDP 14-20 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. R.C.E. 29271 Ex . 3/31/2019 ignature, PE Number & Expiration Date Ronald Holloway Print Name bHA, Inc May 26, 2017 Date 3 (city of Carlsbad STORM WATER STANDARDS QUESTIONNAIRE E-34 land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov To address post-development pollutants that may be generated from development projects, the city requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMPs) into the project design per Carlsbad BMP Design Manual (BMP Manual). To view the BMP Manual, refer to the Engineering Standards (Volume 5). This questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision, discretionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to 'STANDARD PROJECT' requirements or be subject to 'PRIORITY DEVELOPMENT PROJECT' (PDP) requirements. Your responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the city. If you are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, please seek assistance from Land Development Engineering staff. A completed and signed questionnaire must be submitted with each development project application. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. PROJECT NAME: Robert Miles Subdivision PROJECT ID: ADDRESS: 1833 Buena Vista Way Carlsbad, CA APN: 156-220-02 The project is (check one): GZ] New Development O Redevelopment The total proposed disturbed area is: 138,315 ft2 ( 3.17 ) acres The total proposed newly created and/or replaced impervious area is: 54 ,991 ft2 (_1_·2_6 __ ) acres If your project is covered by an approved SWQMP as part of a larger development project, provide the project ID and the SWQMP # of the larger development project: Project ID CT 14-04/PUD 14-06iCDP 14-20 SWQMP #: 14-04 ------------------ 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 To determine if your project is a "development project", please answer the following question: 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)? YES NO D 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): 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: 1. Constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria: a) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non- erodible permeable areas; b) Designed and constructed to be hydraulically disconnected from paved streets or roads; c) Designed and constructed with permeable pavements or surfaces in accordance with USEPA Green Streets uidance? 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? YES NO D D D D D D If you answered "yes" to one or more of the above questions, provide discussion/justification below, then go to Step 5, mark the second box stating "my project is EXEMPT from PDP ... " and complete applicant information. Discussion to justify exemption ( e.g. the project redeveloping existing road designed and constructed in accordance with the USEPA Green Street guidance): If ou answered "no" to the above questions, our ro·ect is not exempt from PDP, o to Step 3. E-34 Page 2 of 4 REV 02/16 To determine if your project is a PDP, please answer the following questions (MS4 Permit Provision E.3.b.(1 )): 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 ublic 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 pro·ect includes develo ment on an natural slope that is twent -five percent or reater. 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 commingled with flows from adjacent lands).* 8. Is your project a new development or redevelopment project that creates and/or replaces 5,000 square feet or more of impervious surface that supports an automotive repair shop? An automotive repair 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 YES NO D D D D D D D D D 0 0 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 statin "M ro·ect is a 'STANDARD PROJECT ... " and com lete a licant information. E-34 Page 3 of 4 REV 02/16 STEP4 TC} Bt: c:c;N1PLE:TE[) F'{)F? f~C[JF.VEL()Pf\,1 Ef<T PR{J,JEC~T:S TH ll.1 t:F? Z. PRi()RlT Y Df\/Et~{)P:viEN f PFt()Jf:.C:T.S. CJf\!L>l' SITE INFORMATION CHECKLIST Project Name Project ID Project Address Assessor's Parcel Number(s) (APN(s)) Project Watershed (Hydrologic Unit) Project Hydrologic Unit Hydrologic Area Parcel Area (total area of Assessor's Parcel(s) associated with the project) Area to be disturbed by the project (Project Area) Project Proposed Impervious Area (subset of Project Area) Project Proposed Pervious Area (subset of Project Area) Robert Miles Subdivision CT 14-04/PUD 14-06/CDP 14-20 1833 Buena Vista Way, Carlsbad, CA 156-220-02 ~ Carlsbad 904 Select One: D Loma Alta 904.1 ~ Buena Vista Creek 904.2 D Agua Hedionda 904.3 D Encinas 904.4 D San Marcos 904.5 D Escondido Creek 904.6 3.265 Acres ( 142,231 Square Feet) 3.17 Acres 138315 SquareFeet) 1.26 Acres 54 991 Square Feet) 1.87 Acres 83,324 Square Feet) Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project. This may be less than the Parcel Area. 6 ~ Existing development D Previously graded but not built out ~ Agricultural or other non-impervious use D Vacant, undeveloped/natural Description I Additional Information: The existing site is currently an operating nursery. Existing Land Cover Includes (select all that apply): ~ Vegetative Cover D Non-Vegetated Pervious Areas ~ Impervious Areas Description I Additional Information: Existing onsite structures include one story single-family residence and single story structures and shade canopies associated with the nursery. Underlying Soil belongs to Hydrologic Soil Group (select all that apply): D NRCS Type A ~ NRCS Type B D NRCS Type C D NRCS Type D The on-site soil classification is Type-B from USGS Web Soil Survey. Approximate Depth to Groundwater (GW): D GW Depth < 5 feet D 5 feet < GW Depth < 1 O feet D 10 feet < GW Depth < 20 feet ~ GW Depth > 20 feet 7 Existing Natural Hydrologic Features (select all that apply): D Watercourses D Seeps D Springs D Wetlands ~ None Description I Additional Information: There are no existing natural hydrologic features. 8 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]: The existing site is currently an operating nursery. Existing onsite structures include one story single-family residence and single story structures and shade canopies associated with the nursery. Topographically, the site is generally flat-lying to very gently sloping in both northwesterly and northeasterly directions. The overall gradient of the site is on the order of 12: 1 or flatter. The site is surrounded by single family residential homes to the north, south, and west. Near the northeasterly margin of the site, an approximate 41-foot high slope descends toward Monroe Street. Storm flows affecting the site are limited to the rainfall that lands directly on this property. There is no flow from upstream properties. The existing drainage area is divided into two basins. Basin A sheet flows from the top of the ridge north-easterly to the intersection of Buena Vista Way and Crest Drive then into an existing 48" storm drain line that connects to the existing storm drain line in Monroe Street which empties into the Buena Vista Lagoon. Basin B sheet flows westerly off the ridge toward the westerly boundary of the subject property onto both Buena Vista Way and McCauley Place then is collected into curb inlet on Valley Street then through storm drain lines on Valley Street, Carlsbad Village Drive, Monroe Street which empties into the Buena Vista Lagoon. Slope stability analyses, performed by GeoSoils, Inc. indicates that the easterly-facing slope, descending from the project site to Monroe Street, possesses the potential for distress to settlements located in close proximity to this slope. Recommendations have been made to keep an open space of land between the proposed private access road and the westerly project boundary line to protect slope failures and erosion. There are no signs of standing water, contiguous natural wetlands, watercourses, seeps, or springs. A second geotechnical investigation was conducted by Geocon Incorporated that was in general concurrence with the geologic characterization of the site. See the "Update Report and Change of Geotechnical Engineer of Record" by Geocon Incorporated, October 14, 2016 in Attachment 4 for modifications and recommendations that should be considered as an update to the GeoSoils Report. The Soil Type for the Project and the offsite-landscaped park is Type "B'' with high permeability based on the Web Soil Survey Report (see Preliminary Drainage Study for this Project) by National Resources Conservation Service (USDA). Group B soils have a moderately fast infiltration rate when thoroughly wet. 9 Project Description I Proposed Land Use and/or Activities: The project proposes the development of 10 residential lots and grading of pads and driveways, a 24-foot wide private access drive and the improvement of the Buena Vista public access drive. The existing single-family residence will be removed as part of the Robert Miles Subdivision Project. Detention basins proposed for the project site runoff so that increases in the drainage discharge rate and velocity will be mitigated up the 100-year runoff. List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): The proposed impervious features of the project include the 1 O single-family residences and associated driveways, the 24-foot wide private access drive, the improvement Buena Vista Way, and meandering sidewalks along northeastern and northwestern project boundary. List/describe proposed pervious features of the project (e.g., landscape areas): The proposed pervious features of the project include landscape areas surrounding the proposed residences and the proposed biofiltration basins on each lot. Does the project include grading and changes to site topography? ~Yes D No Description I Additional Information: Project grading will occur on approximately 3.17 acres of the project. Grading on the site has been minimized to the maximum extent possible. The existing single-family residence will be removed as part of the Robert Miles Subdivision Project. Storm water flows from impervious roof areas will be conveyed via surface flow to the proposed biofiltration basins on each lot. The biofiltration basins will provide treatment of the stormwater prior to discharging to the proposed storm drain system or existing street. The storm drain system will require excavation and installation of underground storm drains. Post-development site flow will mimic existing drainage conditions, and will discharge from the site at below historical flow rates (See Drainage Study for Robert Miles Subdivision CT 14-04, by BHA, Inc., January 13, 2017). Impervious surfaces have been minimized where feasible. 10 Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)? cg] Yes D No Description I Additional Information: The proposed drainage pattern will be similar to the existing drainage pattern with some modifications to incorporate the Best Management Practices (BMPs) into the project design to mimic the impacts on storm water runoff and quality. The proposed runoff from the project site is divided into fourteen (14) Drainage Management Areas (DMAs): (10) Areas Draining to Biofiltration I MPs, (3) Self-retaining DMAs, and (1) Self-Mitigating OMA. The project as proposed will endeavor to maintain the existing cross lot drainage condition for both overall rate, and flow condition. Detention basins proposed for the two (2) main Drainage Basins A and B are proposed so that increases in the drainage discharge rate and velocity will be mitigated up the 100-year runoff. In Basin A, runoff from Lots 1-8 will be conveyed via yard swales to private biofiltration basins located on each lot. The basins will provide storm water treatment and flow detention. Storm water that enters the biofiltration basins will be filtered through the soil media and directed to a perforated underdrain pipe at the bottom of the basin. Discharge from the biofiltration basins will discharge into a proposed bypass storm drain line along-side Buena Vista and the proposed private access drive. The storm drain system will travel north and will outlet into the existing 48" storm drain line located north-easterly to the intersection of Buena Vista Way and Crest Drive. The existing storm drain line will act as POC-1. From POC-1 the storm drain line travels underneath Monroe Street which empties into the Buena Vista Lagoon. In Basin B, runoff from Lots 9-10 will be conveyed via yard swales to private biofiltration basins located on each lot. The basins will also provide storm water treatment and flow detention. Discharge from the biofiltration basins will be conveyed via storm drains and will outlet onto McCauley Place at POC-2. From McCauley Place, runoff is collected into curb inlet on Valley Street then through storm drain lines on Valley Street, Carlsbad Village Drive, Monroe Street which empties into the Buena Vista Lagoon. Runoff from the meandering sidewalk along the eastern project boundary will be directed to landscape areas located adjacent to the sidewalk. The landscape areas are designed to effectively receive and infiltrate, retain and treat runoff from the impervious sidewalk area. Due to the flat nature of the landscape areas, the design of this OMA can reasonable expect that runoff will soak into the soils and produce no runoff of the DCV. This OMA, identified as Self-Retaining OMA (SR 1 ), is designed with the site design BMP-Impervious Area Dispersion-to retain runoff to a level equivalent to the pervious land. 11 Similar to SR 1, runoff from the meandering sidewalk adjacent to Buena Vista Way will be directed to the landscape area that disconnects the sidewalk from Buena Vista Way. The landscape area will also be designed to receive and infiltrate the runoff from the sidewalk impervious area. This OMA, identified as Self-Retaining OMA (SR 2), is designed with the site design BMP-Impervious Area Dispersion-to retain runoff to a level equivalent to the pervious land. Runoff from the portion of driveways of Lot 8-10 that are not feasible to drain to biofiltration basins, and the meandering sidewalk adjacent to McCauley Lane will be directed to landscape areas. The landscape areas are designed to disconnect the sidewalk from McCauley Lane. The landscape areas will also be designed to retain runoff to a level equivalent to pervious land and will be vegetated with native or drought tolerant landscape. Impervious area dispersion has also been used to create this self-retaining OMA-SR 3, and has been designed to meet an impervious to pervious ratio of 1: 1 for soil group B. See Section 5.2.3 of the City of Carlsbad BMP OM for Self-retaining DMAs via Qualifying Site Design BMPs. Runoff from the landscape area located west of Lot 1 will flow directly offsite. The disturbed slope soils will be amended and aerated to promote water retention. The slope will also be vegetated with native or drought tolerant species that do not require regular application of fertilizers and pesticides. This area is classified as a Self-mitigating DMAs per Section 5.2.1 of the BMP OM, and illustrated on the OMA Exhibit as SM 1. See Attachment 1 b for a tabular summary of DMAs, OMA areas, and OMA types. The proposed drainage patterns will not alter the existing flow pattern and will discharge from the site at the historic discharge points. 12 Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply): ~ On-site storm drain inlets D Interior floor drains and elevator shaft sump pumps D Interior parking garages 0 Need for future indoor & structural pest control ~ Landscape/Outdoor Pesticide Use D Pools, spas, ponds, decorative fountains, and other water features D Food service D Refuse areas D Industrial processes D Outdoor storage of equipment or materials D Vehicle and Equipment Cleaning D Vehicle/Equipment Repair and Maintenance D Fuel Dispensing Areas D Loading Docks D Fire Sprinkler Test Water D Miscellaneous Drain or Wash Water ~ Plazas, sidewalks, and parking lots 13 .. ···········ii.. .·· \············· Ii ... Jijijptification••df rR~ceivir1g•VV~tet·Pollu,ntiof c ... ··········· .···•·•··•·······iir .. ···r •. . ... .• i •··••·· .•••• . ....... .. . .. ......... . .. . . .......... Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): Runoff that flows to POC-1 enters into an existing 18" storm drain line that connects to the existing storm drain line in Monroe Street which empties into the Buena Vista Lagoon. Runoff that flows to POC-2 on McCauley Drive is then collected into a curb inlet on Valley Street, then through storm drain lines on Valley Street, Carlsbad Village Drive, and Monroe Street which empties into the Buena Vista Lagoon. All project runoff eventually discharges to the Buena Vista Lagoon, Carlsbad HU through an existing City of Carlsbad MS4. This is are listed for water quality impairment on the most recent 303(d)-list: 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 Indicator bacteria N/a Buena Vista Lagoon (904.21) Nutrients N/a Sedimentation/siltation Nia : ...••... · •... ··· .•. i··· •. ··.·.· .. ·.··.······ ?•·•••ii·.·.••·•.••.· / ..••.. ··· 1~e~,,a~,-~~6t.Pt6J,#~~it<f~~nutt1.~~. T ... ......... . ··. . .. Identify pollutants expected from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6): Not Applicable to Expected from the Also a Receiving the Project Site Project Site Water Pollutant of Pollutant Concern Sediment D ~ ~ Nutrients D ~ ~ Heavy Metals D ~ D Organic Compounds D lSl D Trash & Debris D lSl lSl Oxygen Demanding Substances D lSl ~ Oil & Grease D ~ D Bacteria & Viruses D ~ ~ Pesticides D ~ D 14 Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? D Yes, hydromodification management flow control structural BMPs required. D No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. [8J No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete-lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. D No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides. Description I Additional Information (to be provided if a 'No' answer has been selected above): Storm water runoff from the project site enters a storm drain in Monroe Street which discharges into the Buena Vista Lagoon. Based on Section 1.6 of the City of Carlsbad BMP Design Manual, the City has the discretion to exempt a PDP from hydromodification management requirements if discharge is conveyed via a concrete lined system to an encased embayment (i.e. lagoon). Pursuant to the study approved by the City of Carlsbad titled "Hydromodification Exemption Analyses for Select Carlsbad Watersheds" dated September 17, 2015 prepared by Chang Consultants, the hydrologic and hydraulic analyses performed showed that the hardened system downstream of the project draining to the lagoon conveys the 10-year storm event, the discharge point has proper energy dissipation and the outlet is within the 1 DO-year flood limits. Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? 0Yes [8J No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? D 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite D No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps If optional analyses were performed, what is the final result? D No critical coarse sediment yield areas to be protected based on verification of GLUs on site 15 D Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 8 of the SWQMP. D Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit. Discussion I Additional Information: Hydromodification requirements are not required for this project. 16 . ~Ttdi S~riti~n ... o 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. Hydromodification requirements are not required for this project. Has a geomorphic assessment been performed for the receiving channel(s)? D No, the low flow threshold is 0.102 (default low flow threshold) D Yes, the result is the low flow threshold is 0.102 D Yes, the result is the low flow threshold is 0.302 D Yes, the result is the low flow threshold is 0.502 If a geomorphic assessment has been performed, provide title, date, and preparer: Discussion I Additional Information: (optional) 17 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 local codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements. The project proposes single family residential dwellings constructed on lots that range from 9,500 sf to 13,500 sf. The space available to install suitable private biofiltration basins is very limited. The site currently has an easterly-facing slope descending from the project site to Monroe Street. An open space between the northwesterly boundary line and the proposed private access road will remain untouched to protect the steep slope from failure and erosion. This makes the space available to construct a private access road very limited. Special precautions must be taken while constructing the private access road so that the open space does not channel the flow in any way, but instead the road maintains an even grade and distributes the runoff evenly to the proposed biofiltration basins. A geotechnical investigation has been provided by Geocon addressing the hydraulic capacity of the underlying soils. Based on the Update Report and Change of Geotechnical Engineer of Record dated October 14, 2016, in-situ testing was provided and infiltration rates were obtained ranging between 0.08 and 0.65 inches per hour after applying a factor of safety. The following conclusions were also obtained from the geotechnical investigation: • Compacted fill will be placed across the entire property during site development. The potential for lateral water migration to adversely impact existing or proposed structures, foundations, utilities, and roadways, is high. Therefore full or partial infiltration should be considered infeasible. • Three of the four test indicate an adjusted infiltration rate below the current threshold for infiltration BMPs. • Groundwater was not encountered during the subsurface exploration, nor expected to be a geotechnical constraint. • Stormwater infiltration into the slope that descends from the site to Monroe Street could result in slope instability. Full or partial infiltration should be avoided to prevent lateral water migration, daylight water seepage, and slope stability. • An impermeable liner should be incorporated into the design of the stormwater facilities to prevent water migration. 18 .... . .. o. pt~9na ..•. 1 A ... d.ctJt,on.· .. all6formation.·.·or.<;ootipuatio11ic,f Previoqs••stt~.ti~osAi.~e~<1~c1·· . ...... . ... . ... ... . .. ..... . ... . .. The slope of the project property allows for the concentration and community treatment of the runoff from the entire site prior to discharge. These proposed BMP's can then be easily maintained through the implementation of a Storm Water BMP Maintenance Agreement, or managed by a Home Owners Association. 19 (city of Carlsbad STANDARD PROJECT REQUIREMENT CHECKLIST E-36 Project Name: Robert Miles Subdivision Project ID: CT 14-04/PUD 14-06/CDP 14-20 DWG No. or Building Permit No.: 496-6A Land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See Chapter 4 and Appendix E.1 of the BMP Design Manual for information to implement source control BMPs shown in this checklist. Answer each category below pursuant to the following. • "Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1 of the Model BMP Design Manual. Discussion/justification is not required. • "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed. • "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion/justification may be SC-1 Prevention of Illicit Discharges into the MS4 Discussion/justification if SC-1 not implemented: Irrigation water and vehicle and wash water will be directed away from impervious surfaces. SC-2 Storm Drain Stenciling or Signage Discussion/justification if SC-2 not implemented: Catch basins will be stenciled with anti-dumping signage SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Discussion/justification if SC-3 not implemented: No outdoor material storage areas proposed E-36 Page 1 of 4 ,ppJiect? fll Yes D No Ill Yes D No D N/A D Yes D No IZl N/A Revised 03/16 I>·-···-· •--...... -•·•··• r.-• .. -_ --·sour<:e Contro1·•R~qUirement (cont,11uecfl·•••• ········--.. _ ................... _-_ -• 1-... :.. •. 4.,...,.Ued? •. . ... ·- SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and D Yes D No [l'.J N/A Wind Dispersal Discussion/justification if SC-4 not implemented: No outdoor work areas proposed. SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal D Yes D No fl'.i NIA Discussion/justification if SC-5 not implemented: No trash storage areas proposed 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). @ On-site storm drain inlets rzjYes D No D N/A D Interior floor drains and elevator shaft sump pumps OYes D No 0 N/A D Interior parking garages DYes D No rzj N/A iYl' Need for future indoor & structural pest control D Yes D No D N/A li1 Landscape/Outdoor Pesticide Use D Yes D No D N/A D Pools, spas, ponds, decorative fountains, and other water features D Yes D No flj N/A D Food service D Yes D No ~ N/A D Refuse areas D Yes D No rzj N/A D Industrial processes D Yes D No fZI N/A D Outdoor storage of equipment or materials D Yes D No [] N/A D Vehicle and Equipment Cleaning OYes D No el N/A D Vehicle/Equipment Repair and Maintenance D Yes D No Gt1' N/A D Fuel Dispensing Areas D Yes D No flJ N/A D Loading Docks D Yes D No fl] N/A D Fire Sprinkler Test Water D Yes D No ill N/A ff] Miscellaneous Drain or Wash Water li1 Yes D No D N/A !i1 Plazas, sidewalks, and parkinQ lots @Yes D No D N/A For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers. • Storm drain inlets and catch basins will be labeled with "No Dumping Drains to Waterways" where applicatble. • Pest-resistant or well-adapted plant varieties such as drought tolerant and/or native plants will be planted in landscape areas. • Irrigation systems will be designed for the specific water requirements of each landscape area. Landscaping will be designed to minimize irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to storm water pollution. Flow reducers or shutoff valves triggered by a pressure drop to control water loss in the event of broken sprinkler heads or lines will be used. • Sidewalks must be swept regularly to prevent the accumulation of litter and debris. Debris from pressure washing must be collected to prevent entry into the storm drain system. Washwater containing any cleaning agent or degreaser must be collected and discharged to the sanitary sewer and not discharged to a storm drain. E-36 Page 2 of 4 Revised 03/16 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 I 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. ..... ..... .. S0urce•C:ontro1·Req~~rement••··· SD-1 Maintain Natural Drainage Pathways and Hydrologic Features D No D NIA Discussion/justification if SD-1 not implemented: The overall drainage patterns will be maintained. SD-2 Conserve Natural Areas, Soils, and Vegetation D Yes D No 121 N/A Discussion/justification if SD-2 not implemented: No natural areas exist on the project site. However, project grading has been minimized where feasible SD-3 Minimize Impervious Area Discussion/justification if SD-3 not implemented: Sidewalks will be constructed to minimum widths. streets. 121 Yes D No D N/A Landscape buffe1·s wi!I also be incorporated between sidewalks and SD-4 Minimize Soil Compaction Yes D No D N/A Discussion/justification if SD-4 not implemented: Disturbance in proposed landscape areas will be avoided. In areas planned for landscaping where compaction cannot be avoided, soi! surfaces will be re-tilled to allow for better infiltration capacity. SD-5 Impervious Area Dispersion 0 Yes D No D N/A Discussion/justification if SD-5 not implemented: Landscape wil! etfectively receive and infiltrate, and treat runoff from imprervious areas as much as possible. Roof drains wil! be directed to landscape areas prior to discharging to storm water conveyance system. Impervious areas will be disconnected through distributed pervious surfaces. Runoff from impervious flahvork areas (i e sidewalks) will be directed to pervious or landscape areas pnor to discharging to storm water conveyance. E-36 Page 3 of 4 Revised 03/16 Source Ct:>ntrol Re uiretnenf contioued SD-6 Runoff Collection Discussion/justification if SD-6 not implemented: The Self-retaining areas will implement small collection techniques to col:ect and retain runoff. The Self-retaining areas will a!so minimize the trasport of runoff and poilutants to the MS4 system and receiivng waters. SD-7 Landscaping with Native or Drought Tolerant Species ill!"Yes D No D N/A Discussion/justification if SD-7 not implemented: Slope sons wi!I be amended, aerated. and planted vvith native or drought tolerant non-native plants Other landscape or pervious areas will incorporate native or drought tolei-ant landscape design. SD-8 Harvesting and Using Precipitation D Yes D No NIA Discussion/justification if SD-8 not implemented: Harvest and use is considered to be infeasible for the project site. See Form 1-7 in Attachment 1c. E-36 Page 4 of 4 Revised 03/16 SUMMARY OF 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 local jurisdiction 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 local jurisdiction 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 (page 3 of this form) 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 or separate. For the purpose of this SWQMP, the proposed site condition has been divided into fourteen (14) Drainage Management Areas (DMAs): (10) Areas Draining to Biofiltration IMPs, (3) Self-retaining DMAs, and (1) Self-Mitigating OMA. The DMAs have been delineated based on onsite drainage patters and BMP locations. The type of structural BMP chosen for the project was based on the flow chart presented in Figures 5-1 and 5-2 of the BMP OM. Using Form 1-7 to gauge the feasibility of capture and use techniques for the project site, it was determined that harvest and use BMPs are considered infeasible. A feasibility analysis was then conducted for infiltration and if infiltration is fully or partially feasible for the project's structural BMPs. The negative impacts associated with retention were identified by the geotechnical engineer and substantiated through completion of Form 1-8. A geotechnical report titled "Update Report and Change of Geotechnical Engineer of Record for Robert Miles Subdivision CT 14-04, Carlsbad, California" dated October 14, 2016 was provided 21 by Geocon to summarize the results of site specific geotechnical analyses for the proposed project site. Additionally the geotechnical engineer provided infiltration testing for the design of the planned storm water treatment facilities at the subject site. The study provided the results of infiltration testing using the borehole percolation test method, analysis of field test data, and preparation of Form 1-8. Based on conclusions from the study, the geotechnical engineer has recommended that infiltration of any appreciable amount into onsite soils is not feasible. The biofiltration BMP's would be founded in either compacted fill or dense to very dense old paralic deposits. Infiltration BMP's founded in compacted fill are not recommended due to the potential for lateral water migration, hydro-consolidation, and differential settlement. Infiltration BMP's founded in the underlying old paralic deposits may also result in lateral migration daylight water seepage and slope instability. Please refer to discussions in Appendix C. Slope stability analyses indicated factors of safety below current standards of 1.5 under static conditions if water is allowed to infiltrate into the slope zone soils. Therefore the geotechnical engineer has also recommended the biofiltration basins be lined with an impermeable liner to prevent water infiltration. See Attachment 4 for geotechnical references. Since infiltration is considered infeasible, biofiltration basins (BF-1) were chosen as the structural BMP for DMAs draining to IMPs. Ten (10) LID-BMP biofiltration basins (BF-1) are located within the project site and are responsible for handing pollutant control and peak flow control requirements for DMAs 1-10. In developed conditions, the BMPs will have a uniform surface depth of 1.4 feet. The basins will be designed with a 10-inch ponding layer above the surface for storage volume, an 18-inch layer of amended soil below the surface, and a 12-inch gravel storage layer below the amended soil layer to accommodate the French drain system and . Below the gravel layer the basins are lined to prevent infiltration into the underlying soil. Flows will discharge from the basins via a low flow orifice outlet within the gravel layer to the receiving storm drain system. A riser structure will be constructed within the BMPs with an emergency overflow set 10-inches above the bottom of the basins, such that peak flows can be safely discharged to the receiving storm drain system. The BMPs satisfy pollutant control sizing criteria in Appendix B of the City of Carlsbad BMP DM. The biofiltration basins have been sized based on the minimum sizing factor of 3% for storm water pollutant control requirements. The DCV for each OMA has been calculated based on the proposed impervious roof and landscape areas draining to each BMP. Worksheets B.5-1 in Attachment 1 e further demonstrate that the DCV of each DMA can be fully biofiltered in the basins' storage layers, and the stored effective depth draws down no longer than 36 hours. Additionally, the surface ponding layer can drain down within 24 hours. The detained flow rates for the biofiltration basins have been modeled using the Hydraulic Elements II module within AES and are shown in Attachment 4-Hydrology and Hydraulic Calculations. The biofiltration module can model the underground gravel storage layer, amended soil layer, and a surface storage pond up to the elevation of the invert of the lowest surface discharge opening in the basin riser structure. Ponding above the invert of the lowest surface 22 discharge opening in the basin riser structure is modeled as a detention basin: area vs. elevation and discharge vs. elevation tables are needed by AES for Depth vs. Storage and Discharge Information. It should be noted that detailed outlet structure locations and elevations will be shown on the construction plans based on the recommendations of this study. See the Drainage Report for Robert Miles Subdivision dated January 9, 2017 for basin storage and outflow calculations for detention values to be used for the 100-year peak flow rate in the post-development detained condition. 23 Structural BMP ID No. Basin 1 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 24 '9rfuc1ti<>11.i.i ... :)····· Structural BMP ID No. Basin 2 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) hricfyal D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 25 Structural BMP ID No. Basin 3 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) \:\ .. ,:.,:::l':::i,.:':':':":){:, .. :::·-'"·'1;/: p9~ed ;ttuctu .. ,, ..... D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 26 Structural BMP ID No. Basin 4 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatmenUforebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 27 Structural BMP ID No. Basin 5 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 28 Structural BMP ID No. Basin 6 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 29 Structural BMP ID No. Basin 7 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) [gl Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: [gl Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 30 Structural BMP ID No. Basin 8 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 31 Structural BMP ID No. Basin 9 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) C2J Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: C2J Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 32 QMe sUmmat)' lnformati9g ... . n > QVi~!·•·iijft)nn~fl9q·.'for•eactJ .•. lodividijal••proposed.•struct._,ral ··ii ..... ·.BMPJ··· Structural BMP ID No. Basin 10 DWG 496-6A Sheet No. 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) D Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) D Partial retention by biofiltration with partial retention (PR-1) 0 Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below) D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: 0 Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Discussion (as needed): 33 ATTACHMENT 1 BACKUP FOR PDP POLLUTANT CONTROL BMPS This is the cover sheet for Attachment 1. Check which Items are Included behind this cover sheet: Attachment Contents Checklist Sequence Attachment 1 a OMA Exhibit (Required) ~ Included Attachment 1 b 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 D Included on OMA Exhibit in Attachment 1 a ~ Included as Attachment 1 b, separate from OMA Exhibit Attachment 1 c Form 1-7, Harvest and Use Feasibility ~ Included Attachment 1 d Screening Checklist (Required unless D Not included because the entire the entire project will use infiltration project will use infiltration BMPs 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 D Not included because the entire project will use harvest and use BMPs Attachment 1 e Pollutant Control BMP Design ~ Included Worksheets I Calculations (Required) Refer to Appendices B and E of the BMP Design Manual for structural pollutant control BMP design guidelines 34 Attachment 1 a OMA Exhibit 35 ~o -II !!2--. . ·-V') EXISTING 18" RCP~· · · STORM!!D~t,IN PER ." · · . DWG. 457-4 .' , 0 ; \ . ' -~ .. V) '2> DRAINAGE MANAGEMENT AREA EXHIBIT ROBERT MILES SlJBDIVlSlQN, CITY OF CARLSBAD . . ------· '' '· - -----, ··---... ____ ---'' -------.. -· . . . ------. ""'"""'"'"' '' ··-'" ---.. ·.·:.· ·--/-____ · .-1!!··111··.---.= -.--.ml!!!_~_lllllll•~=:c--•. e11~Rll~lll!~ilcrlll!!_!il~~.u•No•_A 111 RliiYlli:irl· ___ "· -=~ _-(~]:=~-~:~--~:: /·· :: -_· _ ==--.-__ ------..-'=-=-=--=-=/ ~~ I 1 • BASIN 8 --=-i..c1 I 170 SF ,--,-,, I ! ---\ - / ' ' I ~.---------.' I • \ \: l ', . ." . rnJ lr1 !SD-7! I [ I -~\-\ -\ -\-\L ,• ; '' \ i ' I . ~~--+~·, \fl . \ ) ! ' r I 'fl -\~/_,,,.·-·· 11' i : ! \ . ' .: Pf?OJE(:"f;;BOIJ OAF(Y I ' I 1 I i ' r i . -J ; ' ' i I ' . i I I ' ' I SD-3 ' SD-5 II II II 11 * LOT 2 OMA 2 9,480 SF L2 R2 OMA 1 8,103 SF LOT 1 RI [SD-7[ [ill m I \ iSD-7[ [ill iSD-7! ' , . . [E], I [ill I m1 ' r::c...r-'----~-----'-==·=·=--~·-· ·-·- OMA 5 14,169 SF I ' t6 I ' ' ' ' 1-' I ·--I·--/ ., ____ ------!-- L9 LOT 9 r==-==m=--=·· -=--=L=B.....cc'.::..·..;,·./ 1'·1' -· ··' I! . ' ' I --·'i ____ . OMA 8 -- • 10,569 SF ( RB LOT ~ II II F'CC9 ,4:[E] ·, r-~··_···_-.. ·-_·.-J .• ·1 ~~:;f":-;=··==· ·:.:::· ::J , I ~ ,-·. R9 ,'+--' +-" --"h-,,'-\' "'i;r:::::~~ ~--~ ! //. ~"--I 8 I I L, I . I ! I I I -----.. , .. ----------, ..... -----------'V _.(·' I LIO O= -"-::: =r - -_. ~ - -= ·= = = =.,= = -= ~ '-... ·f -). ---~ --- ·._I ' I (, RIO -l ·-m + [ • ~- ' q . '. BASIN 5 200SF-•· .. -.-o LOT 5( . ~-R5 [SD-7[ [ill m ! i ! i i ! I ! ! I L OMA 10 7,855 SF ' ' L1 ...... 't\. ~ ' .. =--,.- . b======;() '. I + ~~ ~ . "! .. ' . ' ' \ \ 'ii. i; \ '' \'' : \ \ i . PR(XJECT BOUNDA~Y--, ; ·, Fl~----------------, Ii; ,/" [ • ' _j LID AND SITE DESIGN: i SD-1 MAINTAIN NATURAL DRAINAGE PATHWAYS AND HYDROLOGIC FEATURES [SD-3 MINIMIZE IMPERVIOUS AREA !SD-4 MINIMIZE SOIL COMPACTION f SD-5 IMPERVIOUS AREA DISPERSION f SD-6 RUNOFF COLLECTION !SD-7 LANDSCAPING WITH NATIVE OR DROUGHT TOLERANT SPECIES K:\Civil 3D\1289-Miles\DWG\SWMP\1289-DMA MAP 3-7-17.dwg, 3/7/201710:44:48 AM SOURCE CONTROL BMPS: i SC-1 [ PREVENTION OF ILLICIT DISCHARGES INTO THE MS4 [SC-2[ STORM DRAIN STENCILING AND SIGNAGE [SC-6 [ ADDITIONAL BMPS BASED ON POTENTIAL RUNOFF POLLUTANTS, IA] ON-SITE STORM DRAIN INLETS [ill NEED FOR FUTURE INDOOR & STRUCTURAL PEST CONTROL m LANDSCAPE/OUTDOOR PESTICIDE USE [E] MISCELLANEOUS DRAIN OR WASH WATER [QJ PLAZAS, SIDEWALKS, DRIVEWAYS, AND PARKING LOTS '-._ ' • PCC 0 BASIN "p,,J_/f·~ 184 S . \ •... -' +·' I SELF-RETAINING DMAS: SELF-RETAINING DMAS ARE AREAS DESIGNED WITH SITE DESIGN BMPS TO RETAIN RUNOFF TO A LEVEL EQUIVALENT TO PERVIOUS LAND. SITE DESIGN BMPS SUCH AS IMPERVIOUS AREA DISPERSION AND PERMEABLE PAVEMENT MAY BE USED INDIVIDUALLY OR IN COMBINATION TO REDUCE OR ELIMINATE RUNOFF FROM A PORTION OF THE PDP. IF A SITE DESIGN BMP IS USED TO CREATE A SELF-RETAINING DMA, THEN THE SITE DESIGN BMPS MUCH BE DESIGNED AND IMPLEMENTED PER THE CRITERIA IN THE APPLICABLE FACT SHEET. THE FACT SHEET CRITERIA FOR IMPERVIOUS ARE DISPERSION FOR MEETING POLLUTANT CONTROL REQUIREMENT DEVELOPED USING CONTINUOUS SIMULATION IS SUMMARIZED BELOW: • SD-5 IMPERVIOUS AREA DISPERSION: A DMA IS CONSIDERED SELF-RETAINING IF THE IMPERVIOUS TO PERVIOUS RATIO IS 1: 1 WHEN THE PERVIOUS AREA IS COMPOSED OF HYDROLOGIC SOIL GROUP B. i O= ___ :·--.':' .•. -. --. ~-,--------~,-------------~---.-+j -.-.-----~-----___J. -=-:::c " --,_ -·-Fi .. SELF-MITIGATING DMAS: VEGETATION IN THE NATURAL OR LANDSCAPE AREA IS NATIVE OR NON-NATIVE DROUGHT TOLERANT SPECIES. SOILS ARE UNDISTURBED NATIVE TOPSOIL~ OR DISTURBED SOILS HAVE BEEN AMENDED AND AERAT~D TO PROMOTE WATER RETENTION CHARACTERISTICS EQUIVALENT TO UNDISTURBED NATIVE TOPSOIL. INCIDENTAL IMPERVIOUS AREAS ARE LESS THAN 5 PERCENT OF THE SELF-Ml Tl GA TING AREA. IMPERVIOUS AREAS CALCULATED WITHIN THE SELF-MITIGATED AREA SHOULD NOT BE HYDRAULICALLY CONNECTED TO OTHER IMPERVIOUS AREAS UNLESS IT IS A STORM WATER CONVEYANCE SYSTEM (SUCH AS BROW DITCHES). THE SELF-MITIGATING AREA IS HYDRAULICALLY SEPARATE FROM DMAS THAT CONTAIN PE.RMANENT STORM WATER POLLUTION CONTROL BMPS. . -" --- II II/ I i\ II I ' II g ' ' ) '\ I I I~- \ \, \ \ \ 1, \ \ \ \ 1 \ \ \ \ \ \ \, ' ' \ \ l ' \ ' \ \, \ \,, \ \ \ Il\ I \ ' ; ' \ I -' --_l___Tl \ \_ \_ \ J_. i \ \_l_J''- <;~' . L . -----.. ~ ----··- b~A,lnc. land planning, elvll englnee~ng, suiveylng 5115 AVENIDA ENCINAS SUITE "L" CARLSBAD, CA. 92008-4387 (760) 931-8700 PROJECT CHARACTERISTICS PARCEL AREA 3,13 ACRES DISTURBED AREA 3.18 ACRES PROPOSED IMPERVIOUS AREA 1.26 ACRES PROPOSED PERVIOUS AREA 1.91 ACRES SOIL TYPE B DEPTH TO GROUNDWATER > 20 FEET LEGEND SYMBOL DMA NAME OMA 1 DMA AREA (SQ FT) 12,197 SF BIOFIL TRATION BASIN NAME BASIN 1 BIOFIL TRATION BASIN AREA (SQ FT) 224 SF DMA BOUNDARY PROPERTY LINE POINT OF CONCENTRATION SELF-RETAINING DMA SELF-MITIGATING DMA DE MINIMIS DMA ROOF AREA LANDSCAPE AREA PROPOSED CONCRETE SIDEWALK, PCC ASPHALT STREET AREA, AC GROUTED UNIT PAYERS PROPOSED BIOFIL TRATION BASIN CONCRETE DRIVEWAY, PCC POC 1 SR 1 SM 1 OMIN 1 R L 1.· .c_•·• ··I I I 1: : ; : ; : ; : ; : ; I 1··_·.,· ..• ,·1 20 10 01111111111111111111"""""2•0 iiiiiiiiiiiiiiiiiiiiiiiiii4 ... 0 """"'""""'""'!'16 o SCALE: 1 " ~ 20' CT 14-04/DWG 496-6A DRAINAGE MANAGEMENT AREA EXHIBIT ROBERT MILES SUBDIVISION CITY OF CARLSBAD, CA SHEET 1 OF 2 \ ' \ \ ' ' ,\ " . ~n--. <tj .. : 1t-~ -V') EXISTING 18" RDP~l STORM IJ{rAIN P£R · - DWG. 457-4 . • . . I . \ ' \ . • \ \ . . ·-0 . . ... (/] ~ \ \ ' \ ! \! • \ I \ . ' \ ' i er i \ ' PFOJEf7ifBOlJ D.ARY • i I ' I I ,• I , ... I f. ~ I I I I I ' ~I I , 'r If· II II II II I I I * # -//--- II BASIN J !J J90 SF I LJ OMA J \ ' -' .. 18,265 SF RJ LOT 3 LOT 2 R2 OMA 2 9,480 SF L2 --! .) -.) I DRAINAGE MANAGEMENT AREA EXHIBIT ROBERT MILES SUBDIVISION, CITY OF CARLSBAD . .. ' , • • • ,_X ' V PCC4 ',,;, i; j' /' / I>- !' -~ + + + (t r---~'"--' --h 11. II II 111 111 II II II II II 11/ II II II II II OMA 4 14,862 SF R4 LOT 4 I ! II I 11 r I\ L4 L._ ____ __J ' ' ; ! I Ii " ' " 'I ' ····· 1--• • .. ... .. --y. ·---;--. • • L'---"'!r"i--'=-'--"c;._t!.x!l, . . " • • --f!L--''---"--,BASIN 6 "PCC6 , ( r3_8_1 _s_F-""I: < " ~ · II I II .L II II II II -/II II OMA 6 14,868 SF R6 -/f · -LOT ;·II' II 111 II ' /? ' I I II II II ii II II II II - II ~ - -II II -, I . u,-1 ~< r·-11 ii " II rl ./11 if ~ -·-··· \ \ \ .... --, - I i ,........ --------··" / I: j ... , \ \ it---r~i=--===S=-=-----~-=-=-=-=-~ ~ ' ' i 1-, i [ I ' I I I ! I --, I L9 L7 OMA 7 10,428 SF ' ' _ LrOT 7 'R7 ~1 ' I LOT 9 \\ ~ -11- /rl II II II . 11-. II/ II II II if- II II/ II ~-----; ll II ·, II II 11 / 8 ____ =---,--eROJEC.LEJ_OUNDA8Y - ' ~=-~-· ---= -~ -/= = --= ="'" -ec-·4. c..Jell~I • ', II II ' L .. BASIN 8 ~-=¥:J I 170 SF i I I/'.---, I' I II I I LB -r-1--) .. -· ,. ..... ~====-~-h1 I , ' .... ·-------. ' I I ' •, ...... I>- •, • ' I I I ' ' OMA 8 10,569 SF RB LOT 8 ••• •-PCCB•·-' ,I ... l• __ ,..-J - " 1, II JI . 11/ II ll g . ,.,,_ --·- -- ) ' , __ ! \ \ ' \ I \ \ \ \ \ ' \ ' \ \, \ \ \ / -·, .. - _....,.--, -" -.... --------- Tl \ I I \ ' L - - ---- ·. \ \.:J- ~- ' \ + fi --~~==------~ \ ~ I ' ' ' BASIN 9 200 SF " i 1 ; j ·.,..:..:>- (/) ~ + BASIN 1 191 SF OMA 1 8,103 SF LOT l .RI ·, L1 ;~ PROJECT BOUNDAR~ -I 1 • _____ i i ' \ ! ,.----------------,-----------· i · L r----, RISER WALL ---+,__,, , 3/8"x16" STAINLESS " ANCHOR BOLTS WITH WING TYPE NUTS (TYP.) RESTRICTOR PLATE 6" PERFORATED ' ORIFICE. D --PVC PIPE BOTTOM OF BA~llv i::" . ' ' 'pt~gSJ-L1i..l~ 11~18Elll~lll~lll~···111 ···111 ···111 ··· 1/4" GAL VAN/ZED STEEL PLATE 6" PVC PERFORATED PIPE ~~ ORIFICE, D, SEE , BMP DIMENSIONS,, THIS SHEET ' ' . ' , 3/8"x16" STAINLESS ANCHOR BOLTS WITH WING TYPE NUTS (TYP.) NOT£-ORIFICE PLATE AND FLANGE CONNECTION TO CONCRETE SHALL BE FITTED WITH JO DUROMETER NEOPRENE RING. RESTRICTOR PLATE DETAIL NOT TO SCALE K:\Civil 3D\1289 -Miles\DWG\SWMP\1289-DMA MAP 3-7-17.dwg, 3/7/201710:44:33 AM I + +- + " i ~· ·- i;, • • I>-_.~ .. --. • ..._ ;...c..... . •, BASIN 5 200 SF OMA 5 14,169 SF R5 ,;,~ V • ,.,;,c \ ' . ' . *ENGINEERED SOIL MIX SHALL PROVIDE A MINIMUM SUSTAINED INFILTRATION RA TE OF 5"/HR. MIX SHALL BE SANDY LOAM TOP SOIL CONSISTING OF 50% SAND, 30% PLANTING SOIL, 20% SHREDDED HARDWOOD MULCH. 2'XJ' TYPE G CATCH f\ BASIN W/ GRATED JNLIT Tf==I _ 1.4' l ,,_ 10" IMPERMEABLE LINER "-=i=""""""'==== ON ALL SIDES, PER SOILS REPORT RESTRICTER PLATE WITH ORIFICE, D, SEE: BMP DIMENSIONS, THIS SHEET BIOFILTRATION BASIN OUTLET DETAIL NOT TO SCALE ~--- I BMPArea BMPID (tt') Basin 1 191 Basin 2 172 Basin3 390 Basin4 381 Basins 250 Basin6 381 Basin? 202 Basin8 170 Basin9 200 Basin 10 185 I =~,~,-----~==~-~---~ -i------- L10 I ' ' I ' ) : L - . - ----.... .L ' BMP DIMENSIONS Gravel Depth Media Depth LID Orifice, D (in) (in) (in) 12 18 1.0 12 18 1.0 12 18 3.0 12 18 1.5 12 18 1.5 12 18 1.5 12 18 1.0 12 18 1.0 12 18 1.0 12 18 1.5 OMA 10 7,855 SF Ponding depth (in) 10 10 10 10 10 10 10 10 10 10 R10 --·1 ' Surface depth (ft) 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 1.4 PCC 0 BASIN 10 184 SF bliA,lnc. land planning, cMI englnee~ng, su;veylng 5115 AVENIDA ENCINAS SUITE "L" CARLSBAD, CA 92008-4387 (760) 931-8700 PROJECT CHARACTERISTICS PARCEL AREA 3.265 ACRES DISTURBED AREA 3.17 ACRES PROPOSED IMPERVIOUS AREA 1.26 ACRES PROPOSED PERVIOUS AREA 1.91 ACRES . SOIL TYPE B DEPTH TO GROUNDWATER > 20 FEET LEGEND SYMBOL DMA NAME OMA 1 DMA AREA (SQ FT) 12,197 SF BIOFIL TRATION BASIN NAME BASIN 1 BIOFIL TRATION BASIN AREA (SQ FT) 224 SF DMA BOUNDARY PROPERTY LINE POINT OF CONCENTRATION SELF-RETAINING DMA SELF-MITIGATING OMA DE MINIMIS DMA ROOF AREA LANDSCAPE AREA PROPOSED CONCRETE SIDEWALK, PCC ASPHALT STREET AREA, AC GROUTED UNIT PAVERS PROPOSED BIOFIL TRA TION BASIN CONCRETE DRIVEWAY, PCC 20 10 0 20 ~~ SCALE: 1" ~ 20' POC 1 SR 1 SM 1 DMIN 1 R L I·'.·., ··,I . . ' ., ' . 1 · I t2'?-VA f++++++J 1·.,·,,·;,,.,·.1 CT 14-04/DWG 496-6A DRAINAGE MANAGEMENT AREA EXHIBIT ROBERT MILES SUBDIVISION CITY OF CARLSBAD, CA SHEET 2 OF 2 _____ I ; I i ! " ' '' ! I Attachment 1 b Tabular Summary of DMAs and Design Capture Volume Calculations DMA Impervious Area Tabulation Surface Name Surface Type Area (ftl Rl Roof and Patio 2,610 PCCl Concrete Drive,va,· 565 DMA Pervious Area Tabulation Surface Name L1 Total Impervious Area (ft) 3,1-;'5 Surface Type Landscape Total Pervious Area (ftl 2 Area (ft) 4,928 4,928 Total DMA (A) 8,103 Total Impervious Area (ft2) /Total DMA (ft2) = Percent Impervious 39° o Soil Type B DMA Runoff Coefficient "C" 0.54 85th Percentile Rainfall (I) 0.59 Design Capture Volume (DVC) = (C)(I)(A) /12 213 36 DMA Impervious Area Tabulation Surface Name Surface Type Area (fl) R.2 Roof and Patio 2,865 PCC2 Concrete Drivnvay DMA Pervious Area Tabulation Surface Name L2 Total Impervious Area (ft1 Surface Type Landsca e 3,239 2 Area (ft) 6,241 Total Pervious Area (ft2) 6,241 Total DMA (A) 9,480 Total Impervious Area (ft2 ) /Total DMA (ft2) = Percent Impervious 34° o Soil Type B DMA Runoff Coefficient "C" O.S 1 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(I)(A) I 12 239 37 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) R3 Roof and Patio 2,610 PCC1 Concrete DriYcwar 910 GP1 Concrete 595 PCC13 Concrete -77 :::,_ c\Cl Asphalt-PriYate Road 3,881 AC2 ,\sphalt-Buena Vista \\'ay 1,055 Total Impervious Area (ft2) 9,578 DMA Pervious Area Tabulation Surface Name Surface Type 2 Area (ft) L3 8,197 U 1 490 Total Pervious Area (ft2) 8,687 Total DMA (A) 18,265 Total Impervious Area (ftl /Total DMA (ft2 ) = Percent Impervious 52°·0 Soil Type B DMA Runoff Coefficient "C" 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(l)(A) I 12 561 38 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) R4 Roof and Patio 2,866 PCC4 Concrete DriYewa,· 892 PCC11 Concrete Dri\·ewa \' 963 ~\C3 o\sphalt-PriYate Road 2,778 GP2 Grouted llnit PaYer 443 Total Impervious Area (ft2 ) 7,942 DMA Pervious Area Tabulation Surface Name Surface Type 2 Area (ft) L4 Landscape Ci,920 Total Pervious Area (ft2 ) 6,920 Total DMA (A) Total Impervious Area (ft2) /Total DMA (ft2) = Percent Impervious Soil Type B DMA Runoff Coefficient "C" 0.62 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(l)(A) I 12 -1-61 39 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) RS Roof and Patio 3,940 recs Concrete DriYewa,· 1,908 Total Impervious Area (ft2) 5,848 DMA Pervious Area Tabulation Surface Name Surface Type LS Landscape Total Pervious Area (ft2) Total DMA (A) Total Impervious Area (ft2 ) I Total DMA (ft2 ) = Percent Impervious Soil Type DMA Runoff Coefficient "C" 85th Percentile Rainfall (I) Design Capture Volume (DVC) = (C)(l)(A) I 12 40 2 Area (ft) 8,321 8,321 14,169 41 °~, B 0.55 0.6 388 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) RCi Roof and Patio 2,866 PCC6 Concrete DriYeway 892 PCC12 Concrete DriYeway 797 ,-\C4 ,\sphalt-Printe Road 2,797 GP3 Grouted Unit Payer 442 Total Impervious Area (ft2) 7,794 DMA Pervious Area Tabulation Surface Name Surface Type Area (ftl L6 Landscape 7,074 Total Pervious Area (ft2 ) 7,lF4 Total DMA (A) 14,868 Total Impervious Area (ft2 ) /Total DMA (ftl = Percent Impervious 52° () Soil Type B DMA Runoff Coefficient "C" 0.61 85th Percentile Rainfall (I) 0.6 Design Capnire Volume (DVC) = (C)(l)(A) /12 45 7 41 DMA Impervious Area Tabulation Surface Name Surface Type R7 Roof and Patio 2,866 PCC7 Concrete DriYcway 770 Total Impervious Area (fl) 3,636 DMA Pervious Area Tabulation Surface Name Surface Type Landscape 6,790 Total Pervious Area (ft2) 6,:'90 Total DMA (A) 10,426 Total Impervious Area (ft2 ) /Total DMA (ft2 ) = Percent Impervious 35° 0 Soil Type B DMA Runoff Coefficient "C" 0.51 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(l)(A) I 12 265 42 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) RS Roof and Patio 2,669 PCCS Concrete DriYeway 1,131 Total Impervious Area (ft2) 3,800 DMA Pervious Area Tabulation Surface Name Surface Type LS Landscape 6,751 Total Pervious Area (ft2) 6,:69 Total DMA (A) 10,569 Total Impervious Area (ft2 ) I Total DMA (ft2 ) = Percent Impervious Soil Type B DMA Runoff Coefficient "C" 0.52 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(l)(A) I 12 '.273 43 DMA Impervious Area Tabulation Surface Name Surface Type Area (ft1 R9 Roof and Patio 2,729 PCC9 Concrete Dri,,eway 710 Total Impervious Area (ft1 3,439 DMA Pervious Area Tabulation Surface Name Surface Type Area (ft1 L9 Landscape 6,228 Total Pervious Area (ft1 6,228 Total DMA (A) 9,667 Total Impervious Area (ft1 I Total DMA (ft1 = Percent Impervious Soil Type B DMA Runoff Coefficient "C" 0.51 85th Percentile Rainfall (I) 0.6 Design Capture Volume (DVC) = (C)(l)(A) I 12 248 44 DMA Impervious Area Tabulation Surface Name Surface Type 2 Area (ft) R10 Roof and Patio 2,729 PCClO Concrete DnYewav 718 Total Impervious Area (ftl 3,447 DMA Pervious Area Tabulation Surface Name Surface Type L10 Lan<lsca pe 4,408 Total Pervious Area (ft2) 4,408 Total DMA (A) 7,855 Total Impervious Area (ft2) /Total DMA (ft2) = Percent Impervious 44°0 Soil Type B DMA Runoff Coefficient "C" 0.56 85th Percentile Rainfall (I) 0.6 Design Capnire Volume (DVC) = (C)(l)(A) I 12 221 45 Runoff Factor Area x Runoff Surface Name 2 (Table B.1-1) Factor e Area (ft L12 Lan<lsca e 9,347 0.1 934.7 PCC14 Concrete 1,938 0.9 1744.2 Ad.usted Surface Drai.tun to Sclf-Retairm1 "--\rea - Recei,-i.t1, Self-Rctami.t1 Surface "\re a -(B) Landsca e 0.26:l Pond De 0.0 m Total .:\rea of DJ\L\ 11,285 Runoff Factor Area x Runoff Surface Name 2 Area (ft ) Table B.1-1) Factor L13 Landsca e 1,369 0.1 136.9 PCClS Concrete 1,053 0.9 947.7 Self-Retairm1 Lan<lsca e 0.67:l Pond De 0.0 m Total ~\rea of DI\L\ 2,422 46 Runoff Factor Area x Runoff Surface Name Surface Type 2 Area (ft ) (Table B.1-1) Factor L14 Landsca e 1,348 0.1 134.8 PCC16 Concrete 1,325 0.9 1192.5 Pond De 0.0 in Total Arca of Dl\L\ 2,673 According to Section B.2.1.3 and Appendix E.3 of the City of Carlsbad Bl\fP Design l\Ianual, a Dl\L\ is considered "Self-retaining" if the impe1Tious to pe1Tious ratio is 1 :1 \vhen the pelTious area is composed of Hydrologic Soil Group B. The locations and limits of all Surfaces Draining to Self-Retaining Dl\fAs are delineated on the Dl\L\ Exhibit. 47 Surface Name LlS Subtotal PctTious Area Roof PCC Subtotal Im etTious Arca Total Self-l\fitigatin Area Percent Im etTious "\rca (Not to Exceed 5°00) 48 2 Area (ft ) 4,161 4,161 0 0 0 4,161 on() D MA Classification Quantity Subtotal DI\L\ (fr2) Subtotal DI\L\ (acres) Self-Miti atin DMAs 1 --1-,161 0.10 Self-Retainin DI\L\s 3 16,380 0.38 Surfaces Drainin to Self-Retainin DI\L\s 0 0 0 Bio retention II\f Ps 10 117,77--1-2.70 Flow Throu h Planter II\f Ps 0 0 0 Infiltration IMP 0 0 0 ConYentional Ye etated Swale 0 0 0 Extended (Dry Detention Basins 0 0 () Media Sand Filter 0 0 0 \Yet Pond 0 0 0 Constructed \\""etland 0 0 0 0 0 0 () 0 0 De I\finimis DI\L\s 0 0 0 Total Project DMA 1--1-138,315 3.18 Total Parcel Area 1--1-2,231 3.27 Comment: 49 PROJECT LOCATION San Diego County 85 th Percentile lsopluvials Legend -85111 PERCENTILE 1S0PLUll1AL : D INCORPORATED CITY NOTE The 85th percentile ,s a 24 hour ra1nfalt Iota! tt represetns a vakJe such that 85% of the observed 24 hour ra,nfaH totals will be less than that value N + • Appendix B: Storm Water Pollutant Control Hydrologic Calculations and Sizing Methods Figure B.1-1: 85th Percentile 24-hour Isopluvial Map B-5 June 2015 Attachment 1 c Form 1-7, Harvest and Use Feasibility Screening Checklist 1. Is there a demand for hatTested water (check all that apply) at the project site that is reliably present during the ,vet season? C8J Toilet and urinal flushing C8J Landscape irrigation D Other: '.?.. If there is a demand; estimate the anticipated aYerage wet season demand oYer a period of 36 hours. Guidance for planning leYel demand calculations for toilet/urinal flushing and landscape irrigation is prmTided in Section B.3.'.?.. tiodified En,·u = ET011uX [[I(PF X K\)/IE] + SL\] X 0.015 LT sing an aYerage nlue for H;\ onr the 14 lots and Lmv Plant \'rater Cse (per Table B.3-2); ~Iodified ET\X"U = 2.7 x [[(O.'.?. x 81,570)/0.9] + OJ x 0.015 Modified ET\'\T= 734 3. Calculate the DCV using worksheet B-2.1. DCV = 3 698 ( cubic feet) 3a. Is the 36 hour demand greater than or equal to the DC\? D Yes I IZI No ¢ J IatTest and use appears to be feasible. Conduct more detailed e,Taluation and sizing calculations to confirm that DCV can be used at an adequate rate to meet drawdmvn criteria. 3b. Is the 36 hour demand greater than 3c. Is the 36 hour demand O.'.?.SDCV but less than the full DC\? less than 0.'.?.5DCV? D Yes I IZI No ¢ HatTest and use may be feasible. Conduct more detailed eYaluation and sizing calculations to determine feasibility. HatTest 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. 50 IZI Yes HatTest and use is considered to be infeasible. Is hatTest and use feasible based on further e,,aluation? D Yes, refer to _:\ppendix E to select and size harYest and use Bl\IPs. [SJ No, select alternate Bl\IPs IIarnst and use Bl\IPs are considered infeasible. Drought tolerant landscape, as proposed in SD-7 in Form E-36, requires low plant water use. Project ,vill implement other LID strategies such as minimizing imper'i'ious area and impetTious area dispersion. The full DCV can be biofiltered in the proposed biofiltration basins. Property owners ·will be encouraged to use rain barrels after construction to reduce runoff Yolumes. 51 Attachment 1 d Form 1-8, Categorization of Infiltration Feasibility Condition See "Update Report and Change of Geotechnical Engineer of Record for Robert Miles Subdivision CT 14-04, Carlsbad, California" by Geocon dated October 14, 2016 in Attachment 4. 52 Attachment 1e Pollutant Control BMP Design Worksheets I Calculations ,. .. •···· ... .. . ( ........ g p ementing retention BJ\IPs 213 cubic-feet Partial Retention 2 Infiltration rate from \X"orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable dra\vdown time for aggregate storage below the undcrdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Linc 3 J 0 inches 5 Aggregate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Line 4 / Linc SJ 0 inches 7 Assumed surface area of the biofiltration Bl\1P 191 sq-ft 8 Media retained pore space 0.1 in/in 9 Volume retained b,· BM P [[Line 4 + (Line 1 2 x Line 8)] / 12] x Linc 7 29 cubic-feet 10 DCV that requires biofiltration [Line 1 -Line 9] 185 cubic-feet BMP Parameters 11 Surface Ponding [6 inch n1inimum, 12 in maximum] 10 inches 12 Media Thickness [18 inches mininmm] 18 inches 13 Aggregate Storage aboYe underdrain ii1Yert (12 inches typical -use O ii1ehes 18 inches for sizing if aggregate 1s not m·er the entire bottom surface area 14 l\1 edia aYaila ble pore space 0.2 ii1/ ii1 15 Media filtration rate to be used for sizing 5 in/hr. Baseline Calculation 16 Allowable Routing Time for sizing 6 hours 1~ Depth filtered durii1g storm [Lii1c 15 x Line 16 J 30 ii1ehes 18 Depth of Detention Storage ii1ehcs 20.8 [Line 11 + (Line 12 x Linc 14) + (Lii1e I 3 x Line 5)] 19 Total Depth Treated [Line 17 + Lii1c 18] 50.8 inches Option 1 -Biofiltet 1.5 times the DCV 20 Required biofiltered ,·olume [1.5 x Lii1e 1 OJ 2--:1 cubic-feet 21 Required Footprint [Line 20 / Linel 9] x 12 65 sq-ft Option 2 -Store 0. 7 5 of remaining DCV in pores and ponding 22 Required Storage (surface + pores) Volume [(J.75 x Lii1e 10] 138 cubic-feet 23 Required Footprint [Linc 22 / Line 1 8 J x 12 80 sq-ft Footprint of the BMP 24 Area draining to the BJ\IP 8,103 sq-ft 7-_::, Adjusted Runoff Factor for drainage area (Refer to i\ppendi.x B.1 and B.2) 0.54 26 J\Iinirnum BJ\IP Footprint [Linc 24 x Line 25 x 0.03] 130 sq-ft 27 Footprint of the BMP = Maxunum(l\limmum(Line 21, Line 23), Lii1c 26) 130 sq-ft 28 Used Bl\IP Footprint 191 sq-ft 53 g g 9 cubic-feet Partial Retention 2 Infiltration rate from \X'orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable drawdown time for a[!brrcgatc storage below the underdrai.n 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Linc 3] 0 inches 5 Aggregate pore space 0.4 in/in 6 Required depth of granl bclmv the underdrain [Linc 4 / Line 5] 0 inches 7 Assumed surface area of the biofiltration BMP l72 sq-ft 8 l\Iedia retained pore space 0.1 in/in 9 Volume retained by Bl\IP [[Line 4 + (Line 12 x Linc 8)]/12] x Line 7 26 cubic-feet 10 DC\' that requires biofiltration [Line 1 -Line 9] 214 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches 12 Media Thickness [18 inches 11l11Urnum] 18 inches 13 Ag__fs[cgatc Storage aboYe underdrain i..t1Yert (12 i..t1ehes typical -use O inches for sizing if aggregate is not oYer the entire bottom surface area 18 inches 14 Media aYailablc pore space 0.2 in/in 15 Media filtration ra tc to be used for sizing 5 in/hr. Baseline Calculation 16 Allowable Routing Time for sizing 6 hours 17 Depth filtered during storm [Li..t1e 15 x Line Hi] 30 inches 18 Depth of Detention Storage 20.8 inches [Line 11 + (Li..t1e 12 x Li..t1e 14) + (Line 13 x Linc 5)] 19 Total Depth Treated [Linc 17 + Line 18] 50.8 inches Option 1-Biofilter 1.5 times the DCV 20 Required biofiltered Yolumc [1.5 x Line 10] 320 cubic-feet 21 Required Footpri..t1t [Line 20 / Linel 9] x 12 76 sq-ft Option 2 -Store 0.75 ofremainine DCV in pores and ponding 2.2 Required Storage (surface+ pores) Volume [0.7 5 x Line 10] 160 cubic-feet 23 Required Footprit1t [Li..t1e 22 / Line 18] x 12 92 sq-ft Footprint of the BMP 24 Area drai..tung to the BI\IP 9,480 sq-ft ') -_:, ,\djusted Runoff Factor for drai..t1agc area (Refer to Appendi..-..;: B.1 and B.2) 0.51 26 Mininrnm Bl\IP Footprint [Li..t1e 24 x Linc 25 x 0.03] 14-1-sq-ft ')""' -! Footpri..tlt of the Bl\IP = I\Iaxirnum(l\I111inrnm(Li..t1e 21, Li..t1c 23), Li..t1e 26) 144 sq-ft 28 Used BMP Footpri..t1t 1 ""'2 sq-ft 54 -Partial Retention 2 Infiltration rate from \X'orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable drawdown time for aggregate storage below the undcrdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3J 0 inches 5 Aggregate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Linc 4 / Line SJ 0 inches 7 Assumed surface area of the biofiltration Bl\f P 390 sq-ft 8 J\Icdia retained pore space (J.1 in/in 9 Volume retained by BMP [[Line 4 + (Line 12 x Line 8)1/12] x Line 7 59 cubic-feet 10 DCV that requires biofiltration [Linc 1 -Line 9J 508 cubic-feet BMP Parameters 11 Surface Ponding [6 inch mininrnm, 12 in maximum] 10 inches 12 Media Thickness [18 inches mininrnmJ 18 inches 13 Aggregate Storage abm-e underdrain i..t1Ycrt (12 i..t1ehcs typical -use O i..t1ehcs 18 inches for sizi..t1g if aggregate is not on'.t the entire bottom surface area 14 Media anilable pore space 0.2 i..t1/in 15 Media filtration rate to be used for sizing 5 i..t1/hr. Baseline Calculation 16 J,llowable Routi..t1g Ti.inc for sizi..t1g 6 hours 1"7 Depth filtered dunng storm [Line 15 x Linc 16] 30 inches 18 Depth of Detention Storage 20.8 inches [Line 11 + (Line 12 x Li..t1e 14) + (Li..t1e 13 x Li..t1e S)] 19 Total Depth Treated [Line 17 + Li..t1e 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltered Yolume [1 .5 x Line 1 OJ 761 cubic-feet 21 Required Footprint [Line 20 / Li..t1cl 9J x 12 180 sq-ft Option 2 -Store 0.75 ofremaining DCV in pores and ponding 22 Required Storage (surface + pores) Volume [0.75 x Li..t1e 10] 381 cubic-feet 23 Required Footpri..t1t [Li..t1c 22 / Line 18] x 12 220 sq-ft Footprint of the BMP 24 ,\rea drai..tung to the Bl\1P 18,265 sq-ft 25 Adjusted Runoff Factor for drainage area (Refer to i\ppendix B.1 and B.2) 0.(>2 26 Mininrnm Bl\IP Footpri..t1t [Li..t1e 24 x Li..t1c 25 x 0.03] 340 sq-ft 2""' Footprint of the BJ\1P = J\Iaximum(l\1i..tmnum(Line 21, Li..t1e 23), Line 26) 340 sq-ft 28 Csed Bl\IP Footpri..t1t 390 sq-ft 55 g DCV after implementing retention Bl'v1Ps 461 cubic-feet Partial Retention 2 Infiltration rate from \X'orkshcct D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable drawdO\vn tin1e for aggregate storage below the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches 5 Aggregate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Line 4 / Line 5 J 0 mchcs 7 Assumed surface area of the biofiltration BI\1 P 381 sq-ft 8 Media retained pore space 0.1 in/in 9 Volume retained b,, BI\IP [[Linc 4 + (Linc 12 x Line 8)]/12] x Line 7 5, cubic-feet 10 DCV that requires biofiltration [Linc 1 -Linc 9] 404 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches 12 Media Thickness [18 inches minimum] 18 inches 13 Aggregate Storage abO\T undcrdrain it1,,crt (12 it1ches typical -use O it1ehes 18 it1ches for sizit1g if aggregate 1s not oyer the entire bottom surface area 14 l\Iedia aYailable pore space 0.2 it1/ ill 15 Media filtration rate to be used for sizit1g 5 in/hr. Baseline Calculation 16 cillowablc Routit1g Titne for sizing 6 hours 17 Depth filtered during storm [Lit1e 15 x Lit1e 16] 30 inches 18 Depth of Detention Storage inches 20.8 [Line 11 + (J~ine 12 x Line 14) + (Linc 13 x Line 5)] 19 Total Depth Treated [Linc 17 + Lit1e 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltered Yolume [1.5 x Line 10] 606 cubic-feet 21 Required Footprint [Line 20 / Lit1e19] x 12 143 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface + pores) Volume [O .7 5 x Lit1e 1 OJ 303 cubic-feet 23 Required I7ootprint [Line 22 / Lit1e 18] x 12 175 sq-ft Footprint of the BMP 2-.J. c\rca draining to the B I\1 P 14,862 sq-ft 25 Adjusted Runoff Factor for drainage area (Refer to ,-\ppendix B.1 and B.2) 0.62 26 Mitlllllum Bl\IP Footpnnt [I ,ine 24 x Lme 25 x (l.03 J T'7 sq-ft 27 Footprit1t of the BMP = I\Iaxinmm(Mitiinmm(Linc 21, Linc 23), Lit1c 26) 277 sq-ft 28 l 1scd BMP Footprit1t 381 sq-ft 56 ~.·,· •. ,· •·· •·• ...•.. · .. ·,, ••··· • + , •t .... t . \ •·< • • ·, ••····• •· ···•··· '' L I < ·····.•.•~ {t t ti t •·· t, < 1 Remaining DCV after implementing retention Bl\1Ps 388 cubic-feet Partial Retention 2 Infiltration rate from \X'orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allmvable drawdown time for a,ggregate storage below the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Linc 2 x Line 3] 0 inches 5 Aggregate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Line 4 / Line 5 J 0 inches -Assumed surface area of the biofiltration Bl\IP 250 sq-ft I 8 Media retained pore space 0.1 in/in 9 Volume retained by Bl\IP [[Line 4 + (Linc 1'.2 x Line 8)]/1:.?] x Linc 7 38 cubic-feet 10 DCV that requires biofiltration [Line 1 -Linc 9] 350 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 1 '.2 in maximum] HJ inches 1 '.2 l\I edia Thickness [18 mches minimum] 18 inches 13 Aggregate Storage aboYe underdrain itn·crt (1 '.2 it1ehes typical -use O inches 18 inches for sizing if aggregate is not oYer the entire bottom surface area 14 l\Iedia aYailablc pore space 0.'.2 it1/in 15 l\1 cdia filtration ra tc to be used for sizit1g 5 in/hr. Baseline Calculation 16 clliowablc Routit1g Titne for sizing 6 hours 17 Depth filtered dunng storm [Lme 15 x Line 16 J 30 it1ehes 18 Depth of Detention Storage inches '.20.8 [Linc 11 + (Linc 1 '.2 x Lit1e 14) + (Lit1e 13 x Line 5)] 19 Total Depth Treated [Linc 17 + Lit1c 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV '.20 Required biofiltcrcd Yolumc [ 1.5 x Lit1c 10 J S'.26 cubic-feet '.21 Required Footprint [Lit1e '.20 / Line 19] x 1'.2 1 '.24 sq-ft Option 2 -Store O. 7 5 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) Volume (0.75 x Lit1e 10] '.263 cubic-feet '.23 Required Footprint [Line '..?'..? / Lit1c 18] x 1 '.2 15'.2 sq-ft Footprint of the BMP '.24 Arca draining to the Bl\IP 14,169 sq-ft ·r _:, Adjusted Runoff Factor for drait1age area (Refer to ,-\ppcndi.x B.1 and B.'.2) 0.55 '.26 l\linitnum Bl\IP Footprit1t [Lit1e '.24 x Line '.25 x 0.03] '.233 sq-ft '.27 Footprint of the Bl\IP = l\laxinmm(l\Iirumum(Line '.21, Lit1e '.23), Lit1e '.26) '.233 sq-ft 28 l'sed Bl\IP Footprint 250 sq-ft 57 ., ····· ........ ~/.·•··········· I ..... 1 Remaining DCV after implementing retention Bl\1Ps 457 cubic-feet Partial Retention 2 Infiltration rate from \'\'orkshcct D.S-1 if partial infltration is feasible 0 in/hr. 3 AllO\vable drawdown time for aggregate storage below the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches 5 ;\ggregate pore space 0.4 in/in 6 Required depth of graHl belO\v the underdrain [Line 4 / Line SJ 0 inches ~ Assumed surface area of the biofiltration Bl\IP 381 sq-ft 8 Media retained pore space 0.1 in/in <) Volume retained b,· Bl\IP [[Line 4 + (Line 12 x Line 8)]/12] x Line 7 51 cubic-feet 10 DCV that requires biofiltration [Line 1 -Line 9] 400 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches 12 l\Icdia Thickness [18 inches minimum] 18 inches 13 Aggregate Storage aboYe underdrain im·crt (12 inches typical -use ll inches for sizing if aggregate is not oYer the entire bottom surface area 18 inches 14 Media aYailable pore space 0.2 in/in 15 1\1 edia filtration rate to be used for sizing 5 in/hr. Baseline Calculation 16 ;\llowable Routing Time for sizing 6 hours l7 Depth filtered during storm [Line 15 x Line 16] 30 inches 18 Depth of Detention Storage 20.8 inches [Line 11 + (Linc 12 x Linc 14) + (Line 13 x Line 5)] 1 <) Total Depth Treated [Linc 1~ + Line 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltered Yolume [1.5 x Line 10] 600 cubic-fret 21 Required Footprint [Line 20 / Line! <JJ x 12 142 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Reciuired Storage (surface+ pores) Volume [0.75 x Line 10] 300 cubic-feet 23 Rec1uired Footprint [Line 22 / I ,ine 18] x 12 F3 sq-ft Footprint of the BMP 24 Area drainmg to the Bl\IP 14,868 sq-ft 25 Adjusted Runoff Factor for drainage area (Refer to ,\ppendi.x B.1 and B.2) () .(>1 26 l\Iininmm Bl\IP Footprint [Linc 24 x Line 25 x (Ul3] 274 sci-ft ')-Footprint of the Bl\IP = Maxin1u111(1\linimum(Line 21, Line 23), Line 26) T'4 sq-ft 28 LT sed Bl\IP Footprint 381 sq-ft 58 g tention Bl\f Ps 265 cubic-feet Partial Retention 2 Infiltration rate from \X"orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 }Jlowable drawdown time for aggregate storage belmv the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3 J 0 inches 5 Aggregate pore space 0.-1-in/in 6 Required depth of granl below the underdra111 [Line 4 / Linc 5] 0 inches 7 Assumed surface area of the biofiltration BMP 202 sq-ft 8 l\Iedia retained pore space 0.1 in/in 9 Volume retained by BJ\IP [[Line 4 + (Line 12 x Line 8))/12] x Line 7 30 cubic-feet 10 DCV that requires biofiltration [Line 1 -Line 9] 235 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches 12 Media Thickness [18 inches minimum] 18 inches 13 Ag__21egate Storage aboYe underdrain inYert (12 inches typical -use O inches for sizing if ag__21egate is not oyer the entire bottom surface area 18 inches 14 Media aYailablc pore space 0.2 in/in 15 Media filtration rate to be used for s12ing 5 in/hr. Baseline Calculation 16 ,-\llowable Routing Time for sizing 6 hours 1-Depth filtered during storm [Line 15 x Line 16] 30 inches 18 Depth of Detention Storage 20.8 inches [Linc 11 + (Linc 12 x Linc 14) + (Line 13 x Line 5)] 19 Total Depth Treated [Line 17 + Line 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltered Yolume [1.5 x Line 10] 353 cubic-feet 21 Required Footprint [Line 20 / Line1 9] x 12 83 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface + pores) Volume [0.75 x Line HJ] 1 "'6 cubic-feet 23 Required Footprint [Line 22 / Linc 18] x 12 102 sq-ft Footprint of the BMP 24 Area draining to the BMP 10,426 sq-ft 25 A.djusted Runoff Factor for drainage area (Refer to Appendi.x B.1 and B.2) 0.51 26 Minimum BMP Footprint [Line 24 x Line 25 x 0.03] 159 sq-ft 2' Footprint of the BJ\IP = J\Iaxinrnm(Minimum(Line 21, Line 23), Linc 26) 159 sq-ft 28 Used BMP Footprint 202 sq-ft 59 ~ ... ······· ···. '\•·•••(,(, .... i,},.~ ~F()•• t••••·•·····\\.t: aining DCY after in1plementing retention BMPs 27 3 cubic-feet Partial Retention 2 Infiltration rate from \'\'orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 ,\llowablc drawdown time for agg;regate storage below the undcrdrain 36 hours 4 Depth of runoff that can be infiltrated [Linc 2 x Line 3] 0 inches 5 ,\ggrcgate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Linc 4 / Linc 5] 0 inches 7 ,\ssumed surface area of the biofiltration BT\IP l70 sq-ft 8 Media retained pore space 0.1 in/in 9 Volume retained b,· BT\IP [[Line 4 + (Line 12 x Linc 8)]/12] x Linc 7 26 cubic-feet 10 DCV that requires biofiltration [Line 1 -Linc 9] 247 cubic-feet BMP Parameters 11 Surface Ponding [6 inch mininmm, 12 in maxinrnm] 10 inches 12 T\ledia Thickness [18 inches mininrnmJ 18 inches 13 Aggregate Storage aboYe underdrain inYert (12 mchcs typical -use O inches 18 inches for sizing if aggregate is not OYer the entire bottom surface area 14 Media anilable pore space 0.2 in/ 111 15 Media filtration rate to be used for sizing 5 in/hr. Baseline Calculation 16 .\llowable Routing Time for sizing 6 hours 1-Depth filtered during storm [Line 1 S x Line 16] 30 inches 18 Depth of Detention Storage inches 20.8 [Lme 11 + (Line 12 x Lmc 14) + (Line 13 x Line 5)] 19 Total Depth Treated [Line 1"' + Line 18] 50.8 inches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltcred Yolume [1.S x Linc 10] 371 cubic-feet 21 Required F ootpnnt [Line 20 / Linc 1 9 J x 12 88 sq-ft Option 2 -Store O. 7 5 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) \Tolume [0.75 x Linc 10] 185 cubic-feet 23 Required Footprint [Line 22 / Linc 18] x 12 1()7 sq-ft Footprint of the BMP 24 Area draining to the B T\1 P 10,569 sq-ft ') -_:, Adjusted Runoff Factor for drainage area (Refer to Appendi.x B.1 and B.2) 0.52 26 T\linirnum BM P Footprint [Line 24 x Linc 25 x 0.03] 164 sq-ft r Pootprint of the BMP = Maxirnum(T\linimum(Linc 21, Linc 23), Line 26) 164 sq-ft 28 L'scd BT\IP Footprint 17 0 sq-ft 60 airiing DCV after implementing retention BMPs 238 cubic-feet Partial Retention 2 Infiltration rate from \'Corksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable drawdmvn time for aggregate storage below the undcrdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches :) Aggregate pore space 0.4 in/in 6 Required depth of granl below the underdrain [Line 4 / Line SJ 0 inches -Assumed surface area of the biofiltration Bl\IP 200 sq-ft 8 1\Icdia retained pore space 0.1 in/in 9 Volume retained b,· Bl\IP [[Line 4 + Qjnc 12 x Line 8)]/12] x Line; 30 cubic-feet 10 DC\' that requires biofiltration [Linc 1 -Line 9] 208 cubic-feet BMP Parameters 11 Surface Ponding [6 inch mini.mum, 12 in maximum] 10 inches 12 Media Thickness [ 18 inches minimum] 18 inches 13 "\ggregate Storage abon underdrain it1,-ert (12 it1ehes typical -use O inches for sizing if a~,regate is not oYer th<.'. entire bottom surface area 18 it1ehcs 14 M cdia aYailable pore space 0.2 in/in 15 M cdia fi.ltra tion rate to be used for sizing s in/hr. Baseline Calculation 16 "\llowable Routing Time for sizit1g 6 hours 1-Depth filtered during storm [Linc 1 S x Line 16 J 30 inches 18 Depth of Detention Storage 20.8 it1ehes [Line 11 + (Lit1c 12 x Line 14) + (Linc 13 x Line 5)] 19 Total Depth Treated [Line 1' + Line 18] 50.8 it1ehes Option 1 -Biofilter 1.5 times the DCV 20 R<.'.qui.red biofi.ltned ,·olume [1.5 x Linc 1 OJ 312 cubic-feet 21 Requit·ed Footprint [Lm<.'. 20 / Line 19] x 12 -4 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface+ pores) Volume [0.75 x Linc 10] 156 cubic-feet 23 Required Footprmt [Lit1e 22 / Lit1e 18] x 12 90 sq-ft Footprint of the BMP 24 Ar<.'.a draining to the BMP 9,1 T7 sq-ft 7-~J "\djusted Runoff Factor for drait1age area (Refer to A.ppendi.x B.1 and B.2) 0.52 26 1\Iit1irnum BMP footpnnt [Line 24 x Line 25 x 0.03] 143 sq-ft 2'7 Footprint of the Bl\IP = 1\Iaximum(Minirnum(Lit1e 21, Linc 23), Line 2(1) 143 sq-ft 28 Csed Bl\IP Footprit1t 200 sq-ft 61 .,,· ... · ... 1 Remaining DCV after implementing retention BMPs 221 cubic-feet Partial Retention 2 Infiltration rate from \'(orksheet D.5-1 if partial infltration is feasible 0 in/hr. 3 Allowable drawdown time for aggregate storage below the underdrain 36 hours 4 Depth of runoff that can be infiltrated [Line 2 x Line 3] 0 inches .5 Aggregate pore space 0.4 in/in 6 Required depth of graYel below the underdrain [Line 4 / Linc 5] 0 inches -,\ssumed surface area of the biofiltration Bi\IP 185 sq-ft 8 Media retained pore space 0.1 in/in 9 Volume retained by Bj\1P [[Linc 4 + (Linc 12 x Linc 8)]/12] x Line 7 28 cubic-feet 10 DCV that requires biofiltration [Linc 1 -Line 9] 193 cubic-feet BMP Parameters 11 Surface Ponding [6 inch minimum, 12 in maximum] 10 inches 12 Media Thickness [18 inches minimum] 18 inches 13 ~\ggregate Storage aboYe underdrain i.twert (12 inches typical -use O i.t1ehes 18 inches for sizing if aggregate is not oyer the entire bottom surface area 14 Media anilable pore space 0.2 111/in 15 Media filtration rate to be used for sizing 5 i.t1/hr. Baseline Calculation 16 ,\llowable Routing Time for sizi.t1g 6 hours 17 Depth filtered during storm [1 "i.t1e 15 x Line 16 J 30 inches 18 Depth of Detention Storage i.t1ehes 20.8 [Line 11 + (Li.t1e 12 x Line 14) + (Line 13 x Line 5)] 19 Total Depth Treated [Line 17 + Li.t1e 18] 50.8 i.t1ches Option 1 -Biofilter 1.5 times the DCV 20 Required biofiltcrcd nilume [LS x Li.t1e 10] 290 cubic-feet 21 Required Footpri.t1t [Line 20 / Line19] x 12 69 sq-ft Option 2 -Store 0.75 of remaining DCV in pores and ponding 22 Required Storage (surface + pores) Volume [0.75 x Line 10] 145 cubic-feet 23 Required Footprint [Line 22 / Line 18] x 12 84 sq-ft Footprint of the BMP 24 ,\tea draining to the BMP 7,855 sq-ft 7" _:, Adjusted Runoff Factor for drainage area (Refer to Appendi.x B.1 and B.2) 0.56 26 Mi.t1imum BMP Footprint [Line 24 x Line 25 x 0.03] 133 sq-ft 27 Footprint of the Bi\IP = Maxi.tnum(Mi.tiimum(Li.t1e 21, Li.t1e 23), Li.t1e 26) 133 sq-ft 28 Csed BMP Footprint 185 sq-ft 62 *£NG/NffRED SOIL MIX SHALL PROVIDE A MINIMUM SUSTAINED INF/L TRA noN RA TE OF SN/HR. MIX SHALL BE SANDY LOAM TOP SOIL CONSISTING OF 50% SAND, 30% PLANnNG SOIL, 20% SHREDDED HARDWOOD MULCH. 2'XJ' TYPE G CATCH BASIN W/ GRATED INLET t RESTRICTER PLATE WITH ORIFICE, D, SEE BMP DIMENSIONS, THIS SHEET BIOFILTRATION BASIN OUTLET DETAIL NOT TO SCALE RISER WALL __ .._.. 3/8nx76" STAINLESS ANCHOR BOLTS WITH WING TYPE NUTS (TYP.) . ·4 RESTRIC TOR PLA TE 6 • PERFORATED ORIFICE, D ----PVC PIPE BOTTOM OF +~iN' ?\ .. · .. · 4 : · ... ~ i i~1H~nf~11 i~,-,·,~111~~11 ~111~111~ . . : ... . -. ··... . . " . ~ . ,d. 1/4" GALVANIZED STEEL . .-:,....· "-----='--'-I PLATE . 6" PVC PERFORATED PIPE-'..,...·-....-+---, J/8"x16" STAINLESS ANCHOR BOLTS WITH WING TYPE NUTS (TYP.) NOTE-ORIFJCE" PLATE AND FLANGE" CONNECTION ORIFICE, D. SEE -.-.. ·-· ----TO CONCRETE SHALL BE" BMP DIMENSIONS.,, · · · • · FITTED WITH JO THIS SHEET • .. ·. ·· ...... ~ .. -. , .. -... -.. -,:-:· ,-.. -:~ ... ·., ~:c~METER NEOPRENE" RESTRICTOR PLATE DETAIL NOT TO SCALf 63 BMP DIMENSIONS BMPArea Gravel Depth Media Depth LID Orifice, D Ponding Surface BMPID (ft2) (in) (in) (in) depth (in) depth (ft) Basin 1 191 12 18 1.0 10 1.4 Basin 2 172 12 18 1.5 10 1.4 Basin 3 390 12 18 3.0 10 1.4 Basin 4 381 12 18 2.0 10 1.4 Basin 5 250 12 18 2.0 10 1.4 Basin 6 381 12 18 2.0 10 1.4 Basin 7 202 12 18 1.5 10 1.4 Basin 8 170 12 18 1.5 10 1.4 Basin 9 200 12 18 1.5 10 1.4 Basin 10 185 12 18 1.5 10 1.4 64 The applicant must prm-ide documentation of compliance with each criterion in this checklist as part of the project submittal. The right column of this checklist identifies the submittal information that is recommended to document compliance with each criterion. Biofiltration B11Ps that substantially meet all aspects of Fact Sheets PR-1 or BF-1 should still use this checklist; however additional documentation (beyond what is already required for project submittal) should not be required. 1. Biofiltration BMPs must be allowed to be used only as described in the BMP selection process based on a documented feasibility analysis. Intent: This manual defines a specific prioritization of pollutant treatment Bl'vIPs, where BMPs that retain water (retained includes evapotranspired, infiltrated, and/ or harvested and used) must be used before considering Bl\IPs that have a biofiltered discharge to the MS4 or surface waters. Cse of a biofiltration Bl\IP in a manner in conflict with this prioritization (i.e., without a feasibility analysis justifying its use) is not pennitted, regardless of the adequacy of the sizing and design of the system. The project applicant has demonstrated that it is not technically feasible to retain the full DCV onsite. Document feasibility analysis and findings in the S\X'Ql\IP per ,\ppendix C. 2. Biofiltration BMPs must be sized using acceptable sizing methods. Intent: The MS4 Permit and this manual defines specific sizing methods that must be used to size biofiltration Bl\IPs. Sizing of biofiltration Bl\IPs is a fundamental factor in the amount of storm water that can be treated and also influences -volume and pollutant retention processes. The project applicant has demonstrated that biofiltration BI\IPs arc sized to meet one of the biofiltration sizing options aYailablc (~\ppendix B). Submit sizing worksheets (.\ppen<lL" B) or other equivalent documentation ,,vith the S\X'Ql\IP. 3. Biofiltration BMPs must be sited and designed to achieve maximum feasible infiltration and evapotranspiration. Intent: Various decisions about Bl\fiJ placement and design influence how much water is retained via infiltration and evapotranspiration. The MS4 Permit requires that biofiltration BMPs achie\-e maximum feasible retention (evapotranspiration and infiltration) of storm water volume. D D D The biofiltration Bl\IP is sited to allow for maximum infiltration of runoff nJlume based on the feasibility factors considered in site planning efforts. It is also designed to maximize eyapotranspiration through the use of amended media and plants (biofiltration designs \vithout amended media and plants may be permissible; see Item 5). For biofiltration Bl\IPs categorized as "Partial Infiltration Condition," the infiltration storage depth in the biofiltration design has been selected to drain in 36 hours or an altcrnatiYe Yalue shown to maximize infiltration on the SltC. For biofiltration Bl\fP locations categorized as "Partial Infiltration Condition," the infiltration storage is over the entire bottom of the biofiltration Bl\IP footprint. For biofiltration Bl\fP locations categorized as "Partial Infiltration Condition," the sizing factor used for the infiltration storage area is not less than the minimum biofiltration Bl\IP sizing factors calculated using \'\'orkshcct B.5.3. An impermeable liner or other hydraulic restriction layer is onfr used when needed to . . aYoid geotechnical and/ or subsurface contamination issues in locations identified as "No Infiltration Condition." The use of "compact" biofiltration Bl\IP design is permitted only in conditions identified as "No Infiltration Condition" and where site- specific documentation demonstrates that the use of larger footprint biofiltration Bl\IT~s would be infeasible. Document site planning and feasibility analyses in the S\'\'Ql\IP per Section 5.4. Included documentation of estimated infiltration rate per Appendix D; proYidc calculations using Appendix B.4 and B.5 to show that the infiltration storage depth meets this criterion. N otc, depths that arc too shallow or too deep may not be acceptable. Document on plans that the infiltration storage coYCrs the entire bottom of the Bl\IP (i.e., not just underdrain trenches); or an cquiYalcnt footprint elsewhere on the site. ProYide a table that compares the minimum sizing factor from "\.ppendix B.5 to the provided sizing factor. Note: The infiltration storage area could be a separate storage feature located downstream of the biofiltration Bl\IP, not necessarily within the same footprint. If using an impermeable liner or hydraulic restriction layer, proYide documentation of feasibility findings per j,ppendix C that recommend the use of this feature. ProYide documentation of feasibility findings that recommend no infiltration is feasible. Prm-ide site-specific information to demonstrate that a larger footprint biofiltration Bl\IP would not be feasible. 4. Biofiltration BMPs must be designed with a hydraulic loading rate to max1m1ze pollutant retention, preserve pollutant control processes, and minimize potential for pollutant washout. Intent: Various decisions about biofiltration Bl\fP design influence the degree to which pollutants are retained. The ]VfS4 Permit requires that biofiltration Bl\fPs achie.-e maximum feasible retention of storm \\'ater pollutants. D T\Icdia selected for the biofiltration BMP meets minimum quality and material specifications per 2016 City Storm \'rater Standards or County LID T\Ianual, including the maximum allowable design filtration rate and minimum thickness of media. OR ,\lternatively, for proprietary designs and custom media mixes not meeting the media specifications contained in the 2016 City Storm Provide documentation that media meets the specifications in 2016 City Storm \'\'ater Standards or County LID T\lanual. \,'ater Standards or County LID Manual, field Provide documentation of performance scale testing data are pro,ridcd to demonstrate that proposed media meets the pollutant treatment performance criteria in Section F 1 below. To the extent practicable, filtration rates arc outlet controlled (e.g., via an underdrain and orifice/weir) instead of controlled by the infiltration rate of the media. The water surface drains to at least 12 inches below the media surface within 24 hours from the end of storm event flow to presen'e plant health and promote healthy soil structure. If nutrients are a pollutant of concern, design of the biofiltration BMP follows nutrient- sensitive design criteria. T\1edia gradation calculations or geotextile selection calculations demonstrate that migration of media between layers will be prevented and permeability will be presenred. information as described in Section F.1. Include outlet control in designs or prmride documentation of why outlet control is not practicable. Include calculations to demonstrate that drawdown rate is adequate. Surface ponding dra,vdown time greater than 24-hours but less than 96 hours mav be allowed at the discretion of Countv staff if certified bv a . . landscape architect or agronomist. Follow specifications for nutrient sensiti,-e design in Jiact Sheet BF-2. Or provide alternative documentation that nutrient treatment is addressed and potential for nutrient release is minimized. Follow specification for choking layer or grntcxtilc in Fact Sheet PR-1 or BF-1. Or include calculations to demonstrate that choking layer is appropriately specified. 5. Biofiltration BMPs must be designed to promote appropriate biological activity to support and maintain treatment processes. Intent: Biological processes arc an important element of biofiltration performance and longevit:y. Plants ha,-e been selected to be tolerant of project climate, design ponding depths and the treatment media composition. Plants haYc been selected to minimize irrigation requirements. Plant location and growth ,,,ill not impede expected long-term media filtration rates and will enhance long term infiltration rates to the extent possible. If plants arc not part of the biofiltration design, other biological processes arc supported as needed to sustain treatment processes (e.g., biofilm in a subsurface flow wetland). Prm-idc documentation justifying plant selection. Refer to the plant list in Appendix E.20. Prm-idc documentation describing irrigation requirements for establishment and long term operation. Provide documentation justifying plant selection. Refer to the plant list in" \ppendix E.20. For biofiltration designs without plants, describe the biological processes that will support effective treatment and how they will be sustained. 6. Biofiltration BMPs must be designed with a hydraulic loading rate to prevent erosion, scour, and channeling within the BMP. D Intent: Erosion, scour, and/ or channeling can disrupt treatment processes and reduce biofiltration effectiYeness. Scour protection has been prm-ided for both sheet flow and pipe inflows to the B"tvfP, where needed. Pnwide documentation of scour protection as described in Fact Sheets PR-1 or BF-1 or appro,·ed equinlent. \'\l1ere scour protection has not been prm-ided, Prm-ide documentation of design checks for flows into and within the B.tvfP are kept to non-erosi,-c Yclocities as described in Fact Sheets erosi,·e velocities. For proprietary Bl\IPs, the BMP is used in a manner consistent with rnanufacturer guidelines and conditions of its third-party certification 19 (i.e., maximum tributary area, maximum inflow ,-elocitics, etc., as applicable). PR-1 or BF-1 or apprm-cd equiYalent. Pro,-ide copy of manufacturer recommendations and conditions of third-party certification. 19 Certifications or Yerifications issued by the \\?ashington Technolo10· .\cceptance Protocol-Ecolo10· program and the .:\'cw Jersey Corporation for .\dvanced Technolo10· programs are typically accompanied ln· a set of guidelines regarding appropriate design and maintenance conditions that ,vould be consistent with the certification/,-erification 7. Biofiltration BMP must include operations and maintenance design features and planning considerations for continued effectiveness of pollutant and flow control functions. D Intent: Biofiltration BMPs require regular maintenance in order provide ongomg function as intended. Additionally, it is not possible to foresee and a,-oid potential issues as part of design; therefore plans must be in place to correct issues if they arise. The biofiltration Bl\fl) maintenance plan describes specific inspection activities, regular/periodic maintenance activities and specific corrective actions relating to scour, erosion, channeling, media clogging, vegetation health, and inflmv and outflmv structures. Adequate site area and features have been provided for Bl\IP inspection and maintenance access. For proprietary biofiltration BI\IPs, the BI\IP maintenance plan is consistent with manufacturer guidelines and conditions of its third-party certification (i.e., maintenance activities, frequencies). Include maintenance plan with the S\'('QI\IP as described in Chapter 7. Illustrate maintenance access routes, setbacks, maintenance features as needed on project water quality plans. Prm-ide copy of manufacturer recommendations and conditions of third-party certification. 1 Potential Sources of Runoff Pollutants !RI A. Onsite storm drain inlets D Not .-\pplicablc !RI 2 Permanent Controls-Show on Drawings Locations of inlets. 3 Permanent Controls-List in Table and Narrative !RI J\Iark all inlets with the words "No Dumping! Flows to Bay" or similar. See stencil template proYided in Appendix I -4 !RI !RI 4 Operational BMPs-Include in Table and Narrative Maintain and periodically repaint or replace inlet markings. ProYide storm water pollution prcyention information to new site owners, lessees, or operators. !RI See applicable operational Bl\IPs in Fact Sheet SC-44, "Drainage Systern l\faintenance," 111 the C\SQ;\ Storm Water Quality Handbooks at www.casqa.r >rg I resources /hmp-han<lbooks I municipal-bmp-handbook. !RI Include the following in lease agreements: "Tenant shall not allow anyone to discharge anything to storm drains or to store or deposit materials so as to create a potential discharge to storm drains." D I&'.) D (XI 1 Potential Sources of Runoff Pollutants B. Interior floor drains and cle\'ator shaft sump pumps Not. \rrlicable C. Interior parking garages Not. \.pplicable [RI D1. Need for future indoor & structural pest control D Not .\nnlicable 2 Permanent Controls-Show on Drawings 3 Permanent Controls-List in Table and Narrative D State that interior floor drains and elevator shaft sump pumps will be plumbed to sanitary sewer. D State that parking garage floor drains will be plumbed to the sanitary sewer. 4 Operational BMPs-Include in Table and Narrative D Inspect and maintain drains to pre\'ent blockages and overflow. D Inspect and maintain drains to pre\Tnt blockages and overflow. [RI Note building design features that I [RI discourage entry of pests. Provide Integrated Pest I\Ianagement information to owners, lessees, and operators. 0 D 1 Potential Sources of Runoff Pollutants D2. Landscape/ Outdoor Pesticide Use Not "-\pplicahle 2 Permanent Controls-Show on Drawings 0 0 0 Show locations of existing trees or areas of shrubs and ground ccffer to be undisturbed and retained. Show self-retaining landscape areas, if any. Show storm water treatment facilities. 3 Permanent Controls-List in Table and Narrative State that final landscape plans will I 0 accomplish all of the following. 0 PresetTe existmg drought tolerant I 0 trees, shrubs, and ground CU\'er to the maximum extent possible. 0 Design landscaping to m11111n1ze irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to storm water pollution. 0 Where landscaped areas are used to retain or detain storm water, specify plants that are tolerant of periodic saturated soil conditions. 0 Consider using pest-resistant plants, especially adjacent to hardscape. 0 To ensure successful establishment, select plants appropriate to site soils, slopes, climate, sun, wind, rain, land use, air 1novement, ecological consistency, and plant interactions. 0 4 Operational BMPs-Include in Table and Narrative I\faintain landscaping usmg minimum or no pesticides. See applicable operational BJ\fPs in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Storm \v'ater Quality Handbooks ~ \\WW.C<lSlft.r>rgLrc~r)HfU..':ci/llmp · ha!idbtHlks/mun1cip:il··bmp Provide IPl\I ne\V O\Vners, operators. information to lessees and 1 Potential Sources of Runoff Pollutants D E. Pools, spas, ponds, decorative fountains, and other water features. lx'.I '.\:ot .-\pplicable D F. food sen-ice lx'.I Not ~\.pplicablc D 2 Permanent Controls-Show on Drawings Show location of water feature and a sanita1T sewer cleanout in an accessible area within 10 feet. D for restaurants, grocery stores, and other food sen-ice operations, show location (indoors or in a cm-ered area outdoors) of a floor sink or other area for cleaning floor mats, containers, and equipment. D On the drawing, show a note that this drain will be connected to a grease interceptor before discharging to the sanitary sewer. 3 Permanent Controls-List in Table and Narrative D If the local nrnnicipality requires pools to be plumbed to the sanitary sewer, place a note on the plans and state in the narrati,-e that this connection will be made according to local requirements. D Describe the location and features of the designated cleaning area. D Describe the items to be cleaned in this facility and how it has been sized to ensure that the largest items can be acco1nmodated. 4 Operational BMPs-Include in Table and Narrative D Sec applicable operational BMPs in Fact Sheet SC-72, "Fountain and Pool Maintenance," in the CASQ,\ Storm \'vater Quality Handbooks at p.::b.0mU2~•.L2.k,;/municipal Lmr)-handbn( 1k, 1 Potential Sources of D G. Refuse areas ll!;I 1':ot "\pplicable 2 Permanent Controls-Show on Drawings D Show where site refuse and recycled materials will be handled and stored for pickup. See local municipal requirements for sizes and other details of refuse areas. D If dumpsters or other receptacles arc outdoors, show how the designated area will be covered, graded, and pa,red to prevent rnn-011 and show locations of berms to prevent runoff from the area. /\lso show how the designated area ,vill be protected from wind dispersal. D Any drains from dumpsters, compactors, and tallow bin areas must be connected to a grease removal de,rice before discharge to sanitary sewer. 3 Permanent Controls-List in Table and Narrative D State how site refuse will be handled and provide supporting detail to what is shown on plans. D State that signs ,vill be posted on or near dumpsters with the words "Do not dump hazardous materials here" or sitnilar. 4 Operational BMPs-Include in Table and Narrative D State how the following will be itnplcmentcd: Prm,ide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky receptacles. Keep receptacles covered. Prohibit/pre,rcnt dumping of liquid or hazardous wastes. Post "no hazardous materials" signs. Inspect and pick up litter daily and clean up spills immediately. Keep spill control materials available on-site. Sec Fact Sheet SC-34, "Waste Handling and Disposal" in the C\SQA Storm Water Quality Handbooks at lrnndbl 1( 1k_~i n1 urncu.2.iJJt_J_mp_-hanJlH )( )i'._. 1 Potential Sources of Runoff Pollutants D H. Industrial processes. ~ Not .-\pplicable D I. Outdoor storage of equipment or materials. (Sec rows J and K for source control measures for Yehiclc cleaning, repair, and maintenance.) [XI 1'1ot .\pplicable I I 2 Permanent Controls-Show on Drawings D Show process area. D D Show any outdoor storage areas, including how materials will be cm·crcd. Show how areas will be graded and bermcd to pre,·ent run-on or runoff from area and protected from wind dispersal. Storage of non-hazardous liquids must be co,·ered by a roof and/ or drain to the sanitary sewer system, and be contained by berms, dikes, liners, or ,·aults. D Storage of hazardous materials and wastes must be 111 compliance with the local hazardous materials ordinance and a Hazardous Materials Management Plan for the site. 3 Permanent Controls-List in Table and Narrative D If industrial processes are to be located onsite, state: '\\ll process acti,·ities to be performed indoors. No processes to drain to exterior or to storm drain system." D Include a detailed description of materials to be stored, storage areas, and structural features to pre,-cnt pollutants from entering storm drains. Where appropnatc, reference documentation of compliance with the requirements of local Hazardous Materials Programs for: • Hazardous Waste Generation • Hazardous Materials Release Response and Im·cntory • California Accidental Release Pre,·ention Program • Abm·cground Storage Tank • Uniform Fire Code ,\rticlc 80 Section 103(b) & (c) 1991 • LTnderground Storage Tank 4 Operational BMPs-Include in Table and Narrative Table and Narrative D See Fact Sheet SC-10, "Non-Storm Water Discharges" in the CASQ,\ Storm Water Quality Handbooks at http\:// \V\V\V .G1,,q..,L24\.L.Ic:,nu rccs/bm1) handbook". D See the Fact Sheets SC-31, "Outdoor Liquid Container Storage" and SC-33, "Outdoor Storage of Raw l\Iaterials" 111 the CASQA Storm Water Quality Handbooks at D r:xJ 1 Potential Sources of Runoff Pollutants J. Vehicle and Equipment Cleaning Not .\pplicable 2 Permanent Controls-Show on Drawings D Show on drawings as appropriate: (1) Commercial/industrial facilities having ,,chicle / cc1uipmcnt cleaning needs must either provide a covered, bcrmed area for ,vashing acti,-ities or discourage ,-chicle/ equipment washing by rc1rnwing hose bibs and installing signs prohibiting such uses. (2) l\Iulti-dwclling complexes must han a paved, bcrmcd, and cm-ered car wash area ( unless car washing is prohibited onsite and hoses arc prm-idcd with an automatic shut-off to discourage such use). (.1) Washing areas for cars, \'ehiclcs, and equipment must be paved, designed to prevent run-on to or runoff from the area, and plumbed to drain to the sanitary sewer. (4) Commercial car wash facilities must be designed such that no runoff from the facility is discharged to the storm drain system. Wastewater from the facility must discharge to the sanitary sewer, or a wastewater reclamation system must be installed. 3 Permanent Controls-List in Table and Narrative D If a car wash area is not prmridcd, describe measures taken to discourage onsitc car washing and explain how these will be enforced. 4 Operational BMPs-lnclude in Table and Narrative Describe operational measures to irnplemcnt the following (if applicable): D Washwater from vehicle and equipment washing operations must not be discharged to the storm drain system. D D Car dealerships and similar mav rinse cars with water only. Sec Fact Sheet SC-21, "V chicle and Equipment Cleaning," 111 the C\SQ,\ Storm Water Quality Handbooks at www.cas,FL(,rg/ re::;, )tircc:i_lbrn phnndbooks/1111micip,11 bmp · lunc.lbooL 1 Potential Sources of Runoff Pollutants D K. \' chicle/Equipment Rep au and ~Iaintenance IXl Not .\pplicablc D D D 2 Permanent Controls-Show on Drawings Accommodate all ,·chicle equipment rep au and maintenance indoors. Or designate an outdoor work area and design the area to protect from rainfall, run-on runoff, and wind dispersal. Show secondary containment for exterior work areas where motor oil, brake fluid, gasoline, diesel fuel, radiator fluid, acid-conta111111g batteries or other hazardous materials or hazardous ,vastes arc used or stored. Drains must not be installed within the secondary containment areas. ~\dd a note on the plans that states either (1) there are no floor drains, or (2) floor drains arc connected to wastewater pretreatment systems prior to discharge to the sanitary sewer and an industrial \Vaste discharge permit will be obtained. 3 Permanent Controls-List in Table and Narrative D D D State that no \Thiele repair or maintenance will be clone outdoors, or else describe the rcquuccl features of the outdoor work area. State that there arc no floor drains or if there arc floor drains, note the agency from which an industrial waste discharge permit will be obtained and that the design meets that agency's requirctnents. State that there arc no tanks, containers or sinks to be used for parts cleaning or rinsing or, if there are, note the agency from which an industrial waste discharge permit will be obtained and that the design meets that agency's requirements. 4 Operational BMPs-lnclude in Table and Narrative In the report, note that all of the following restrictions apply to use the site: D No person must dispose of, nor permit the disposal, directly or incluectly of \'chicle fluids, hazardous materials, or rinsewater from parts cleaning into storm drains. D No ,·ehiclc fluid rcmm·al must be performed outside a building, nor on asphalt or ground surfaces, whether inside or outside a building, except in such a manner as to ensure that any spilled fluid will be in an area of secondary containment. Leaking ,·ehiclc fluids must be contained or drained from the \Thiele immediately. D No person must lea,·e unattended drip parts or other open containers containing vehicle fluid, unless such containers are in use or in an area of secondary contai111nent. 1 Potential Sources of Runoff Pollutants D L. Fuel Dispensing Areas Qi! Not.\pplicable D 2 Permanent Controls-Show on Drawings r-li l(, h 'ue ng areas 111ust a,Te impermeable floors (i.e., portland cement concrete or cqui,·alent smooth impervious surface) that arc (1) graded at the minimum slope necessary to preycnt ponding; and (2) separated from the rest of the site by a grade break that prcyents run-on of storm water to the l\IEP. D fueling areas must be cmTred by a canopy that extends a minimum of ten feet in each direction from each pump. f"\lternati,Te: The fueling area must be cmTered and the cmTer's minimum dimensions must be equal to or greater than the area within the grade break or fuel dispensing area 1.] The canopy [or coYcrJ must not drain onto the fueling area. 3 Permanent Controls-List in Table and Narrative D D 4 Operational BMPs-lnclude in Table and Narrative The property owner must dry sweep the fueling area routinely. See the Business Guide Sheet, ""\utomotiYc Stations" in the Water Quality Se1Yice-Scrvice C\SQ1\ Storm Handbooks at l . ; • ·1 1tt_p.i: / / www.ca~-'-~-!.C,\,;;Lfc~utl[<; __ (c'.,S/ J 16 The fueling area must be defined as the area extending a minimum of 6.5 feet from the corner of each fuel dispenser or the length at which the hose and nozzle assembly may be operated plus a minimum of one foot, whichever is greater. 1 Potential Sources of Runoff Pollutants M. Loading Docks IXI '.'.i ot "\pplicablc 2 Permanent Controls-Show on Drawings D Show a preliminary design for the loading dock area, including roofing and drainage. Loading docks must be cmTered and/ or graded to minimize run-on to and runoff from the loading area. Roof downspouts must be positioned to direct storm water away from the loading area. Water from loading dock areas should be drained to the sanitary sewer where feasible. Direct connections to storm drains from depressed loading docks are prohibited. D Loading dock areas draining directly to the sanitary sewer must be equipped with a spill control \·ake or equi,Talent de,·ice, which must be kept closed during periods of operation. D Pro,-ide a roof m·erhang over the loading area or install door skirts (cowling) at each bay that enclose the end of the trailer. 3 Permanent Controls-List in 4 Operational BMPs-Include in Table and Narrative D i'\Ion: loaded and unloaded items indoors as soon as possible. D See Fact Sheet SC-30, "Outdoor Loading and Unloading," in the C\SQA Storm Water Oualitv Handbooks at '-" www.ca,;cp.on~/ n.:s( ,u recs /hn1p-handh>;_•k~ !_municipal bm_p ha_ndb," ,k. 1 Potential Sources of Runoff Pollutants 0 N. Fire Sprinkler Test \'vater W J\.iot A.pplicahle 0. Miscellaneous Drain or Wash Water 0 Boiler drain lines 0 Condensate <lrain lines 0 Rooftop equipment 0 Drainage sumps 0 Roofing, gutters, and trim JX:I 0'.ot s\pplicable 2 Permanent Controls-Show on Drawings 0 3 Permanent Controls-List in Table and Narrative Provi<le a means to <lrain fire sprinkler test water to the sanitary sewer. D Boiler drain lines must be directly or indirectly connectc<l to the sanitary sewer system and may not discharge to the storm drain system. 0 Condensate drain lines may discharge to lan<lscaped areas if the flow is small enough that runoff will not occur. Con<lcnsate drain lines may not discharge to the storm <lrain system. D Rooftop mounted equipment with potential to produce pollutants must be roofed an<l/ or have secondary containment. 0 ;\ny drainage sumps onsite must feature a sc<liment sump to reduce the quantity of sediment in pumped water. 0 1-\ voi<l roofing, gutters, an<l trim made of copper or other unprotecte<l metals that may leach into runoff. 4 Operational BMPs-Include in Table and Narrative 0 Sec the note in Fact Sheet SC-41, "Buil<ling and Groun<ls Maintenance," in the CASQA Storm Water Quality Handbooks at w,vw .ca:;cp.r >rg / rc:<ou rcc:s /brn pJ1andhc1<Jks I n1unic1p~d.--.bmp··. rm ~ 1 Potential Sources of Runoff Pollutants P. sidewalks, parking lots. Plazas, and D Not ,\pplicable 2 Permanent Controls-Show on Drawings 3 Permanent Controls-List in Table and Narrative !xi 4 Operational BMPs-lnclude in Table and Narrative Plazas, sidewalks, and parking lots must be swept regularly to pre\'ent the accumulation of litter and debris. Debris from pressure washing must be collected to pre\·ent entry into the storm drain system. Washwater containing any cleaning agent or degreaser must be collected and discharged to the sanitary sewer and not discharged to a storm drain. ATTACHMENT 2 Structural BMP Maintenance Information 65 Attachment 2a Structural BMP Maintenance Thresholds and Actions 66 PRIVATE TREATMENT CONTROL BMP OPERATION AND MAINTENANCE VERIFICATION FORM BIORETENTION FACILITIES, VEGETATED SWALES & HIGHER RATE BIOFILTERS 1. Transcribe the following information from your notification letter and make corrections as necessary: Permit No.: BMP Location: Responsible Party: Phone Number: Email: Responsible Party Address: Number Street Name & Suffix City/Zip D Check here for Address or phone number change 2. Using the Table below, please describe the inspections and maintenance activities that have been conducted during the fiscal year (July 1 -June 30), and date(s) maintenance was performed. Under "Results of Inspection," indicate whether maintenance was required based on each inspection, and if so, what type of maintenance. If maintenance was required, provide the date maintenance was conducted and a description of the maintenance. REFER TO THE BACK OF THIS SHEET FOR MORE INFORMATION DESCRIBING TYPICAL MAINTENANCE INDICATORS AND MAINTENANCE ACTIVITIES. If no maintenance was required based on the inspection results, state "no maintenance required." Results of Inspection: Date Maintenance Completed and Date Work needed? Description of Maintenance Conducted What To Look For? Inspected (Yes/No) Accumulation of Sediment, Litter, Grease Standing Water Erosion Overgrown Vegetation Poor Vegetation Establishment Structural Damage 3. Attach copies of available supporting documents (photographs, copies of maintenance contracts, and/or maintenance records). 4. Sign the bottom of the form and return to: Signature of Responsible Party County of San Diego Watershed Protection Program Department of Public Works 5510 Overland Ave., Suite 410, MS 0326 San Diego, CA 92123 OR Email: Watersheds@sdcounty.ca gov Print Name Date PRIVATE TREATMENT CONTROL BMP OPERATION AND MAINTENANCE VERIFICATION FORM BIORETENTION FACILITIES, VEGETATED SWALES & HIGHER RATE BIOFILTERS-SIDE 2 This guide sheet provides general indicators for maintenance only and for a wide array of treatment control BMPs. Your developer prepared maintenance plans specifically for your treatment control BMP as an appendix to the Stormwater Management Plan. Also, if you have a manufactured structure, please refer to the manufacturer's maintenance instructions. Biofilters include the following : D Vegetated Filter Strip/Swale D Bioswale D Bioretention Facility D Planter Boxes D Manufactered Higher-Flow-Rate Biofilters, such as Tree-Pit-Style Units. Routine maintenance is needed to ensure that flow is unobstructed, that erosion is prevented, and that soils are held together by plant roots and are biologically active. Typical maintenance consists of the following: Bioretention BMPs Inspection and Maintenance Checklist Typical Maintenance Indicators Typical Maintenance Actions Accumulation of sediment (over 2 inches deep or Remove and properly dispose of accumulated materials, covers vegetation), litter, or debris without damage to the vegetation. Confirm that soil is not clogging and that the area drains after a storm event. Till or replace soil as necessary. Poor vegetation establishment Ensure vegetation is healthy and dense enough to provide filtering and to protect soils from erosion. Replenish mulch as necessary (if less than 3 inches deep), remove fallen leaves and debris, prune large shrubs or trees, and mow turf areas. Overgrown vegetation-woody vegetation not part Mow or trim as appropriate, but not less than the design of design is present and grass excessively tall height of the vegetation (typically 4-6 inches for grass). (greater than 10 inches) Confirm that irrigation is adequate and not excessive and that sprays do not directly enter overflow grates. Replace dead plants and remove noxious and invasive weeds. Erosion due to concentrated irrigation flow Repair/re-seed eroded areas and adjust the irrigation. Erosion due to concentrated stormwater runoff flow Repair/re-seed eroded areas and make appropriate corrective measures such as adding erosion control blankets, adding stone at flow entry points, or re-grading where necessary.Remove obstructions and sediment accumulations so water disperses. Standing water (BMP not draining) . If mosquito Where there is an underdrain, such as in planter boxes larvae are present and persistent, contact the San and manufactured biofilters, check the underdrain piping Diego County Vector Control Program at (858) 694-to make sure it is intact and unobstructed. Abate any 2888. Mosquito larvicides should be applied only potential vectors by filling holes in the ground in and when absolutely necessary and then only by a around the biofilter facility and by insuring that there are licensed individual or contractor. no areas where water stands longer than 96 hours followinq a storm . Obstructed inlet or outlet structure Clear obstructions. Damage to structural components such as weirs, Repair or replace as applicable. inlet, or outlet structures Before the wet season and after rain events: remove Where cisterns are part of the system sediment and debris from screens and overflow drains and downspouts; ensure pumps are functioning, where applicable; check integrity of mosquito screens; and; check that covers are properly seated and locked. For manufactured high-flow-rate biofilters, see manufacturer's maintenance guidelines Bio Retention Basin Inspection & Maintenance Checklist I Property: Property Owner: Date of Inspection: lnspector(s) Name: Address: Basin Location: OMA# __ Phone: Type of Inspection 0Monthly D pre-wet season 0After heavy runoff D End of wet season Oother: ( 1" or greater) Y=Yes N=No MR=Maintenance Required NA= Not Applicable Vegetation & Irrigation: §Vegetation is dead or diseased Vegetation & Irrigation systems in good condition Overgrown 0Neat and orderly in appearance Required Maintenance: Soil: 0Too deep or too shallow (the distance from the top of mulch to the top of riser pipe shall be 4") Required Maintenance: Page1of 3 Mulch: § Missing or Patchy in Appearance Depth of mulch layer less than 3-in Areas of Bare earth Sediment, Trash & Debris: 0Accumulated sediment, trash,and debris present D Drain time exceeds 4 hours Required Maintenance: Clogs: Structural Components: ~~~~~~~~~~~~~~~~~~~~~~- §Soil too deep or too shallow accumulated sediment, trash and debris Drain time more than 5 days after rainfall Flow to basin is impeded inflow pipes or downspouts are cloged/damaged damaged splash/rock blocks Over flow pipe in damaged or cloged Underdrain pipes cloged or damaged Planter is cracked, leaking or falling apart Page 2 of 3 Inspector Signature: _________ _ Date: -------- Inspector Signature: _________ _ Date: -------- The basin shall be drained within 5 days after each storm event, standing water for more than 5 days will cause mosquito breeding, contact County of San Diego Vector Control Program at (858) 694-2888. ** The Responsible Party shall retail the maintenance/inspection records for a minimum of 5 years from the date of maintenance.The records shall be made available to the County of San Diego for inspection upon request at any time. Page 3of 3 ... BIORETENTION FACILITIES These facilities remm'e pollutants primarily by filtering runoff slowly through aerobic, biologically acti,,e soil. Routine maintenance is needed to ensure that flow is unobstructed, that erosion is preYented, and that soils are held together by plant roots and are biologically acti,,e. Typical maintenance consists of the following: • • • • • • • Inspect inlets for channels, exposure of soils, or other evidence of erosion. Clear any obstructions and remoYe any accumulation of sediment. Examine rock or other material used as a splash pad and replenish if necessary. Inspect outlets for erosion or plugging . Inspect side slopes for evidence of instability or erosion and correct as necessary . ObserYe the surface of bioretention facility soil for uniform percolation throughout. If portions of the bioretention facility do not drain within 24 hours after the end of a storm, the soil should be tilled and replanted. Remm'e any debris or accumulations of sediment. Confirm that check dams and flow spreaders arc in place and leYel and that ri,'Ulets and channelization are cffectiYely preYented. Examine the vegetation to ensure that it is healthy and dense enough to proYide filtering and to protect soils from erosion. Replenish mulch as necessary, remoYe fallen lea,·es and debris, prune large shrubs or trees, and mow turf areas. When mowing, remoYe no more than 1/,height of grasses. Confirm that irrigation is adequate and not cxcessi,,e and that sprays do not directly enter oYerflow grates. Replace dead plants and remoYe noxious and inYasiYe yegetation. "\bate any potential vectors by filling holes in the ground in and around the bioretention facility and by insuring that there arc no areas where water stands longer than 48 hours following a storm. If mosquito larYae are present and persistent, contact the San Diego County \T cctor Control Program for information and ad,,ice. l\Iosquito larvicides should be applied only when absolutely necessary and then only by a licensed individual or contractor. Attachment 2b Draft Maintenance Agreement I. Purpose and Scope This section was prepared based on the Chapter 7 of City of Carlsbad BMP Design Manual The goal is to insure that the Project proponent accepts responsibility for all facilities maintenance, repair, and replacement from the time they are constructed until the ownership and maintenance responsibilities is formally transferred to the new owner. Facilities shall be maintained in perpetuity and comply with the City's self-inspection, reporting, and verification requirements. II. Inspection, Maintenance Log and Self-Verification Forms Fill the forms on the following pages for each BMP using the maintenance schedule here and the inspection-maintenance checklists in Section VII. These forms shall be signed by the responsible party and retained for at least (5) years. Use the OMA Exhibit for the location of BMPs. (Make duplicate copies of these forms and fill out those, not the original ones.) Ill. Updates, Revisions and Errata This maintenance plan is a living document and based on the changes made by maintenance personnel, such as replacement of mechanical equipments, addition maintenance procedure shall be added and maintenance plan shall be kept up to date. Please add the revisions and updates to the maintenance plan to this section if any, these revisions maybe transmitted to the City at any time. However, at a minimum, updates to the maintenance plan must accompany the annual inspection report. IV. Introduction The Robert Miles Subdivision Project is located at 1833 Buena Vista Way, City of Carlsbad. The proposed project is a 3.27-acre site. The project site drains to two (2) Points of Compliance located near the northern and southern corners of the project site. The existing site is currently an operating nursery with one story single-family residence and single story structures on site. The project proposes the development of 1 O residential lots and grading of pads and driveways, a 24-foot wide private access drive and the improvement of the Buena Vista public access drive. The existing single-family residence will be removed as part of the Robert Miles Subdivision Project. Detention basins proposed for the project site runoff so that increases in the drainage discharge rate and velocity will be mitigated up the 100-year runoff. The existing single-family residence will be removed as part of the Robert Miles Subdivision Project. 67 V. Responsibility for Maintenance A. General Robert Miles will enter into a Stormwater Facilities Maintenance Agreement (SWFMA) with the City of Carlsbad to maintain designated facilities herein this section for the Robert Miles Subdivision Project. The SWFMA will serve as the mechanism to ensure that proper inspection and maintenance is done in an efficient and timely manner. Responsible Party Robert Miles Miles Pacific Limited Partnership 1833 Buena Vista Way Carlsbad, CA 92008 760-889-9011 Robert Miles will have the direct responsibility for maintenance of Stormwater controls. A Home Owner's Association (HOA) shall be formed, or establish another mechanism to the satisfaction of the City. Funding for the maintenance activities shall be provided by Robert Miles, the HOA, or other mechanism to the satisfaction of the City. Whenever the property is sold and whenever designated individual change, immediately the updated contact information must be provided to the City of Carlsbad. B. Staff Training Program Staff training and education program shall be carried out twice a year, once prior to the rainy season (October 1st) and once during the early dry season (April 3Qth). The inspection and maintenance training program consists of the operation and function of the biofiltration basins. Please refer to the sections VI and VII for fact sheets and checklists. It is the responsibility of Robert Miles to convey the maintenance and inspection information to the employees. Maintenance personnel must be qualified to properly maintain stormwater management facilities. Inadequately trained personnel can cause additional problems resulting in additional maintenance costs. C. Records Robert Miles shall retain education, inspection, and maintenance forms and documents for at least five (5) years. 68 D. Safety Keep safety considerations at the forefront of inspection procedures at all times. Likely hazards should be anticipated and avoided. Never enter a confined space (outlet structure, manhole, etc) without proper training or equipment. A confined space should never be entered without at least one additional person present. If a toxic or flammable substance is discovered, leave the immediate area and contact the local Sheriff at 911. Potentially dangerous (e.g., fuel, chemicals, hazardous materials) substances found in the areas must be referred to the local Sheriff's Office immediately for response by the Hazardous Materials Unit. The emergency contact number is 911. Vertical drops may be encountered in areas located within and around the facility. Avoid walking on top of retaining walls or other structures that have a significant vertical drop. If a vertical drop is identified within the pond that is greater than 48" in height, make the appropriate note/comment on the maintenance inspection form. VI. Summary of Drainage Areas and Stormwater Facilities A. Drainage Areas The proposed drainage pattern will be similar to the existing drainage pattern with some modifications to incorporate the Best Management Practices (BMPs) into the project design to mimic the impacts on storm water runoff and quality. The proposed runoff from the project site is divided into fourteen (14) Drainage Management Areas (DMAs): (10) Areas Draining to Biofiltration I MPs, (3) Self-retaining DMAs, and (1) Self-Mitigating OMA. The project as proposed will endeavor to maintain the existing cross lot drainage condition for both overall rate, and flow condition. Detention basins proposed for the two main Drainage Basins A and B are proposed so that increases in the drainage discharge rate and velocity will be mitigated up the 100-year runoff. In Basin A, runoff from Lots 1-8 will be conveyed via yard swales to private biofiltration basins located on each lot. The basins will provide storm water treatment and flow detention. Storm water that enters the biofiltration basins will be filtered through the soil media and directed to a perforated underdrain pipe at the bottom of the basin. Discharge from the biofiltration basins will discharge into a proposed bypass storm drain line along-side Buena Vista and the proposed private access drive. The storm drain system will travel north and will outlet into the existing 48" storm drain line located north-easterly to the intersection of Buena Vista Way and Crest Drive. The existing storm drain line will act as POC-1. From POC-1 the storm drain line travels underneath Monroe Street which empties into the Buena Vista Lagoon. 69 In Basin B, runoff from Lots 9-10 will be conveyed via yard swales to private biofiltration basins located on each lot. The basins will also provide storm water treatment and flow detention. Discharge from the biofiltration basins will be conveyed via storm drains and will outlet onto McCauley Place at POC-2. From McCauley Place, runoff is collected into curb inlet on Valley Street then through storm drain lines on Valley Street, Carlsbad Village Drive, Monroe Street which empties into the Buena Vista Lagoon. Runoff from the meandering sidewalk along the eastern project boundary will be directed to landscape areas located adjacent to the sidewalk. The landscape areas are designed to effectively receive and infiltrate, retain and treat runoff from the impervious sidewalk area. Due to the flat nature of the landscape areas, the design of this OMA can reasonable expect that runoff will soak into the soils and produce no runoff of the DCV. This OMA, identified as Self-Retaining OMA (SR 1), is designed with the site design BMP-Impervious Area Dispersion-to retain runoff to a level equivalent to the pervious land. Similar to SR 1, runoff from the meandering sidewalk adjacent to Buena Vista Way will be directed to the landscape area that disconnects the sidewalk from Buena Vista Way. The landscape area will also be designed to receive and infiltrate the runoff from the sidewalk impervious area. This OMA, identified as Self-Retaining OMA (SR 2), is designed with the site design BMP-Impervious Area Dispersion-to retain runoff to a level equivalent to the pervious land. Runoffs from the portion of driveways of Lot 8-10 that are not feasible to drain to biofiltration basins, and the meandering sidewalk adjacent to McCauley Lane will be directed to landscape areas. The landscape areas are designed to disconnect the sidewalk from McCauley Lane. The landscape areas will also be designed to retain runoff to a level equivalent to pervious land and will be vegetated with native or drought tolerant landscape. Impervious area dispersion has also been used to create this self-retaining OMA-SR 3, and has been designed to meet an impervious to pervious ratio of 1: 1 for soil group B. See Section 5.2.3 of the City of Carlsbad BMP OM for Self-retaining DMAs via Qualifying Site Design BMPs. Runoff from the landscape area located west of Lot 1 will flow directly offsite. The disturbed slope soils will be amended and aerated to promote water retention. The slope will also be vegetated with native or drought tolerant species that do not require regular application of fertilizers and pesticides. This area is classified as a Self-mitigating DMAs per Section 5.2.1 of the BMP OM, and illustrated on the OMA Exhibit as SM 1. See Attachment 1 b of the SWQMP for a tabular summary of DMAs, OMA areas, and OMA types. B. Treatment and Flow-Control Facilities Ten (10) LID-BMP biofiltration basins are located within the project site and are responsible for handling treatment control requirements for DMAs 1-10. In developed conditions, the basins will have a uniform surface depth of 1.4 feet and an internal outlet structure. Flows 70 will then discharge from the basin via the outlet structure or infiltrate through the base of the facilities to the receiving amended soil and low flow orifice. The riser structure will act as a spillway such that peak flows can be safely discharged to the receiving storm drain system. Beneath the basin's invert lies the proposed LID biofiltration portion of the drainage facilities. This portion of the basin is comprised of a 3-inch layer of mulch, an 18-inch layer of amended soil (a highly sandy, organic rich composite with an infiltration capacity of at least 5 inches/hr) and a 12-inch layer of gravel. An underdrain will also be provided at the bottom of the basin to carry way filtered runoff to the proposed storm drain system. The bottom of the basin will be lined with an impermeable liner to prevent infiltration into native soils. See the OMA Exhibit for the location of BMPs. The biofiltration basins are designed to treat and detain runoff. Pollutants are removed as the runoff passes through the soil layer and the underlying layer of gravel or drain rock. A perforated underdrain pipe will convey flow to the proposed storm drain system. Infiltration of the storm water will not be allowed, and the basins will be lined with a 30-mil HOPE impermeable liner. See the "Update Report and Change of Geotechnical Engineer of Record" by Geocon Incorporated, October 14, 2016 for basin liner and subdrain recommendations. There will be an overflow outlet, which will convey flows that exceed the capacity of the basins. The basins for this Project are sized for pollutant control only, based on the City of Carlsbad BMP Design Manual. VII. Facility Documentation Please see the following pages regarding the BMPs details and maintenance fact sheets. VIII. Maintenance Schedule and Checklist Fill out the checklists in the following pages for each BMP. The required maintenance activities are at the end of this section. At the discretion of the Project proponent, a qualified Stormwater company may be hired to perform the required inspection and maintenance and provide necessary reports. 71 Bio Retention Basin Inspection & Maintenance Checklist I Property: Property Owner: Date of Inspection: lnspector(s) Name: Address: Basin Location: OMA# __ Phone: Type of Inspection 0Monthly D pre-wet season 0After heavy runoff D End of wet season Oother: ( 1" or greater) Y=Yes N=No MR=Maintenance Required NA= Not Applicable Vegetation & Irrigation: §Vegetation is dead or diseased Vegetation & Irrigation systems in good condition Overgrown D Neat and orderly in appearance Required Maintenance: Soil: 0Too deep or too shallow (the distance from the top of mulch to the top of riser pipe shall be 4") Required Maintenance: Page1of3 Mulch: § Missing or Patchy in Appearance Depth of mulch layer less than 3-in Areas of Bare earth Sediment, Trash & Debris: 0Accumulated sediment, trash,and debris present D Drain time exceeds 4 hours Required Maintenance: Clogs: Structural Components: ~~~~~~~~~~~~~~~~~~~~~~~ §Soil too deep or too shallow accumulated sediment, trash and debris Drain time more than 5 days after rainfall Flow to basin is impeded inflow pipes or downspouts are cloged/damaged damaged splash/rock blocks Over flow pipe in damaged or cloged Underdrain pipes cloged or damaged Planter is cracked, leaking or falling apart Page 2 of 3 Inspector Signature: _________ _ Date: _______ _ Inspector Signature: _________ _ Date: _______ _ The basin shall be drained within 5 days after each storm event, standing water for more than 5 days will cause mosquito breeding, contact County of San Diego Vector Control Program at (858) 694-2888. ** The Responsible Party shall retail the maintenance/inspection records for a minimum of 5 years from the date of maintenance The records shall be made available to the County of San Diego for inspection upon request at any time. Page 3of 3 ... BIORETENTION FACILITIES These facilities remoYC pollutants primarily by filtering runoff slowly through aerobic, biologically acti,Te soil. Routine maintenance is needed to ensure that flow is unobstructed, that erosion is pre,Tented, and that soils are held together by plant roots and arc biologically active. Typical maintenance consists of the following: • • • • • • • Inspect inlets for channels, exposure of soils, or other evidence of erosion. Clear any obstructions and remmTe anv accumulation of sediment. Examine rock or other material used as a splash pad and replenish if necessary. Inspect outlets for erosion or plugging . Inspect side slopes for evidence of instability or erosion and correct as necessary . Obscnre the surface of bioretcntion facility soil for uniform percolation throughout. If portions of the bioretention facility do not drain within 24 hours after the end of a storm, the soil should be tilled and replanted. Remove any debris or accumulations of sediment. Confirm that check dams and flow spreaders are in place and level and that rin1lets and channelization are effecti,Tely prevented. Examine the vegetation to ensure that it is healthy and dense enough to provide filtering and to protect soils from erosion. Replenish mulch as necessary, remm·c fallen lca,Tes and debris, prune large shrubs or trees, and mow turf areas. When mowing, remove no more than 11., height of grasses. Confirm that itrigation is adequate and not excessive and that sprays do not directly enter m·erflow grates. Replace dead plants and remove noxious and 111,Tasl\'e vegetation. Abate any potential vectors by filling holes in the ground in and around the biorctention facility and by insuring that there are no areas where ,vater stands longer than 48 hours following a storm. If mosquito lanTae are present and persistent, contact the San Diego County Y ector Control Program for information and ad,Ticc. Mosquito lafficides should be applied only when absolutely necessary and then only by a licensed individual or contractor. ATTACHMENT 3 City standard Single Sheet BMP (SSBMP) Exhibit 72 .. ----=--,t,-L~ ---=--' • ,C..C • --~=--=---=as.= -~--:;:-~i'lll •s -1----W---:"":::·-s1 w://i-r~ ~--EI.L · · ·:·. ~~~Nsf:--= __ '-L;,'-,. -~ = /-_~1~'Ns/;__-----,------I'-........ -. --· \ i ' i \ ' \ \ I \ ' ' ' \ \ \ \ \ \ \ \ _\ ' i. \ \ \ \ i \ ; lW i . '_ j' ' i ! ". ,;, ' ·--I\_ ,r, I \ ,c ' '·, ~'-''-{{~, - 1" t ,t-t T + + + \ \ \ \ \ K:\Civil 30\1289 -Miles\DWG\SWMP\1289-SMP PLAN SHEET 1 · 13· 17.dwg, 3/7/2017 10:42:50 AM .. ,• . ___ ._.. . . ' *' .. ~•· ' -. 'r---t t -" . --· --- .. ··---- . --·- -.. ·-. ····-() ·:_:-~----·.: - ... - ·--~·'·'-'·--· .. "'-· . ' ,.: ~ ~--· '•'' -..... ,. . I ' ' I \ \ ~~ \ ' \ ............ _,,, ,-, ~ \ \ \ ' I ' i i I ' I LOT 8 ./ GRAPHIC SCALE \ \ ' ' ' ' \ 1"=30' ' ' \ \ . ~-------~-1-...i.t!!!!!!.~~I 0 :3Q 60 90 SWMP NO. _1~4-~04~-- PARTY RESPONSIBLE FOR MAINTENANCE: NAME ROBERT MILES ADDRESS 1833 BUENA Vl~TAWAY CARLSBAD CA 92008 CARLSBAD CA 92008 PHONE NO. /7601889-9011 CONTACT ROBERT MILES PLAN PREPARED BY: NAME RONALD HOLLOWAY COMPANY~B~H~A~IN~C~·----~ ADDRESS 5115 AVENIDA ENCINAS ~1JM SIGNATURE 1 0 SUITE L CARLSBAD CA 92008 PHONE NO. 17601931-8700 BMP NOTES: CERTIFICATION------ 1. THESE BMPS ARE MANDATORY TO BE INSTALLED PER MANUFACTURER'S RECOMMENDATIONS OR THESE PLANS. 2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING TYPES WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY INSPECTION STAFF HAS INSPECTED THIS PROJECT FOR APPROPRIATE BMP CONSTRUCTION AND INSTALLATION. 5. REFER TO MAINTENANCE AGREEMENT DOCUMENT. 6. SEE PROJECT SWMP FOR ADDITIONAL INFORMATION. BMP BMP ID# BMPTYPE SYMBOL CASOA NO. QUANTITY TREATMENT CONTROL CD BIOFIL TRA TION + + + + TC-32 ___.1fil_ SF. AREA + .. + + + + + + + 0 BIOFIL TRA TION + + + + TC-32 -112.._SF. AREA + + + + + + + + + Q) BIOFILTRATION + + .. • TC-32 --3filL SF. AREA + + .. • + + + + + © BIOFILTRATION + + -1-+ TC-32 _3!lLSF. AREA + + + t + + + + + ® BIOFILTRATION + + + + TC-32 ---2filL SF. AREA + + + + + ;-+ + + ® BIOFILTRATION + + + + TC-32 _3!lLSF. AREA + + + • + + ·+ + + 0 BIOFIL TRATION + + + .. TC-32 -2QZ__SF. AREA + + + .... + + + + BIOFIL TRATION . ® + + + t, TC-32 _.1llLSF. AREA .. + .. + + + .. t + ® BIOFILTRATION + t + + TC-32 ____.2QQ__ SF. AREA + + + + + + + + + @ BIOFILTRATION + + + + TC-32 ---1.8o... SF. AREA + + + + + .. + + + LOW IMPACT DESIGN (L.I.D.) @-@) ROOF DRAIN TO • SD-11 20 EA. LANDSCAPING * CHOOSE FROM THE LIST BELOW FOR COMPLETING THE FIELDS IN THE INSPECTIONS & MAINTENANCE FRENQUENCY COLUMNS: ANNUAL SEMI-ANNUALLY QUARTERLY BIMONTHLY MONTHLY AS NEEDED NONE WEEKLY 1 TIME PER YEAR 2 TIMES PER YEAR 3 TIMES PER YEAR 4 TIMES PER YEAR ·. TABLE DRAWING NO. 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A 444-4A INSPECTION * MAINTENANCE * SHEET NO.(SI FREQUENCY FREQUENCY 4, 5 QUARTERLY SEMI-ANNUALLY 4, 5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4, 5 QUARTERLY SEMI-ANNUALLY 4,5 QUARTERLY SEMI-ANNUALLY 4, 5 QUARTERLY SEMI-ANNUALLY 4, 5 ANNUALLY ANNUALLY I SHlET I CITY OF I SH1ETS I CARLSBAD ENGINEERING DEPARTMENT SINGLE SHEET BMP SITE PLAN ROBERT MILES SUBDIVISION RECORD COPY PROJECT NO. CT 14-0y'PUD 14-06/ CD 14-20 DATE INITIAL DATE INITIAL I DRAWING NO. I REVISION DESCRIPTION OTHER APPROVAL CITY APPROVAL INITIAL DATE 496-6A . Attachment 4 Geotechnical Study 73 GE OCON INCORPORATED GEOTECHNICAL ENVIRONMENT AL MATERIALS UPDATE REPORT AND CHANGE OF GEOTECHNICAL ENGINEER OF RECORD ROBERT MILES SUBDIVISION CT 14-04 CARLSBAD, CALIFORNIA PREPARED FOR SHEA HOMES SAN DIEGO, CALIFORNIA OCTOBER 14, 2016 PROJECT NO. G2037-32-01 GEOCON INCORPORATED ------------------------------···· GEOTECHNICAl u ENVIROf\lMENTAL l!ll MATER AS Project No. G2037-32-0l October 5, 2016 Shea Homes 9990 Mesa Rim Road San Diego, California 92121 Attention: Subject: Ms. Sarah Morrell UPDATE REPORT AND CHANGE OF GEOTECHNICAL ENGINEER OF RECORD ROBERT MILES SUBDIVISION CT 14-04 CARLSBAD, CALIFORNIA Dear Ms. Morrell: In accordance with your request, this correspondence has been prepared to document that Gcocon Incorporated will accept the role of Gcotechnical Engineer of Record for the subject project. As part of this acceptance, we have reviewed the following documents. 1. Preliminary Geotechnical Evaluation, Proposed Residential Subdivision, 1833 Buena Vista Way, Carlsbad, San Diego Coun(v. California, prepared by GcoSoils Incorporated, dated March 17, 2014. 2. Grading Plans/ix Robert Miles Subdivision, Carlsbad. CA, prepared by BHA Inc., undated. Based on a review of the referenced report prepared by GeoSoils, we are in general concurrence with the geologic characterization of the site and recommendations provided unless superseded herein. Summarized below are modifications and recommendations that should be considered as an update to their report dated March 17, 2014. MODIFICATIONS AND RECOMMENDATIONS 1.0 Grading Recommendations An undocumented fill embankment exists along the top of the eastern slope of the property. Although exploratory excavations were not performed in this area, it appears that the embankment is up to 6960 Flanders Drive 1111 Son D,ego, California 92121-2974 !lll Telephone 853.558.6900 ill Fox 858.558.6159 approximately 5 to 7 feet thick and contains abundant organic debris. This material will reqmre removal and compaction as part of the project remedial grading and it is possible that the organic content is such that removal and export of this embankment will be required. All grading should be performed in accordance with the attached Recommended Grading Specifications (Appendix A). All earthwork should be observed and all fills tested for proper compaction by Geocon Incorporated. To reduce the potential for differential settlement, it is recommended that the cut portion of cut/fill transition building pads be undercut at least 3 feet and replaced with properly compacted "very low" to "low" expansive fill soils. Where the thickness of the fill below the building pad exceeds 15 feet, the depth of the undercut should be increased to one-fifth of the maximum fill thickness. 2.0 Slope Stability Evaluation Slope stability analyses were performed on the approximate 60-foot high, northeast facing slope that descends to Monroe Street. The analysis utilized the computer software program GeoStudio 2007 to provide appropriate design recommendations to achieve a factor of safety of at least 1.5 against deep- seated failure. The results of the analyses indicate that the existing slope exhibits static and pseudo- static factors of safety of at least 1.5 and 1.0, respectively, and is considered acceptable. An evaluation forcing the failure surface eastward of the most critical surface indicates the calculated factor of safety increases slightly. In their slope stability analysis, the previous consultant identified the most critical surface along the easterly facing slope which yielded a factor of safety of 1.5 against deep seated failure. This line was identified on the Tentative Map as a setback boundary where improvements were restricted or required special consideration when located within this zone. Based on the results of our analysis, it is our opinion that this restriction is not necessary and typical recommendations for improvements located near the top of slopes ( e.g. seven foot to daylight for wall foundations, etc.) are appropriate. In accordance with Special Publication 117 A guidelines, site specific seismic slope stability analyses are required for sites located within mapped hazard zones. Seismic Hazard Zone maps published by CDMG, including landslide hazard zones, have not been published for San Diego County due to the relatively low seismic risk compared with other jurisdictions in Southern California. Therefore, it is our opinion that providing seismic slope stability analyses is not required. However, to be consistent with the previous geotechnical report, we are presenting seismic slope stability analyses on the most critical failure surfaces in accordance with Recommended Procedures for Implementation of DMG Special Publication 117: Guidelines for Ana(v::ing and Mitigating Land\'lide Hazards in California, Project No. G2037-32-0I - 2 -October 14. 2016 prepared by the Southern California Earthquake Center (SCEC), dated June 2002, and Special Publication 117 A, dated September 2008. The se1sm1c slope stability analysis was performed usmg a peak ground acceleration of 0.23g, corresponding to a 10 percent probability of cxceedance in 50 years for a soft rock condition. In addition, a deaggregation analysis was performed on the 0.23g value for the site. A modal magnitude and modal distance of 6.8 and 9 .2 kilometers, respectively, was used in the analysis and a plot of the hazard contribution is shown in Appendix B, Figure B-7. Using the parameters discussed herein, an equivalent site acceleration, kEQ, of 0.13 g was calculated to perform the screening analysis and/or seismic slope stability analysis, as shown in Appendix B. The screening analysis was performed using an acceleration of 0.13g resulting in factors of safety ranging between 1.2 and 1.6. Table 2.2 presents a summary of the seismic slope stability screening evaluation. A slope is considered acceptable by the screening analysis if the calculated factor of safety is greater than I. 0 using kEQ; therefore, the most critical failure surfaces depicted on Cross-Sections A-A' and B-B' pass the screening analysis for the seismic slope stability. The output files and calculated factor of safety for the cross sections used for the stability analyses arc presented in Appendix B and summarized in Tables 2.1 and 2.2. TABLE 2.1 STATIC SLOPE STABILITY SUMMARY Cross Section Figure Number Condition Analyzed Factor Of Safety A-A' 8-1 Circular Failure Through Qop 1.5 8-8' 8-4 Circular Failure Through Qop 2.1 TABLE 2.2 SEISMIC SLOPE STABILITY SCREENING EVALUATION (KEo = 0.13G) Cross Section Figure Number Condition Analyzed Factor Of Safety Pass/Fail A-A' 8-2 Circular Failure Through Qop 1.2 Pass 8-8' 8-5 Circular Failure Through Qop 1.6 Pass The previous borings and laboratory testing, and existing and proposed topography were considered in the stability analyses. The cross section geometry of the subsurface conditions was developed by interpolating and extrapolating the information obtained in the exploratory borings. The computer Project No. G2037-32-0J - 3 -October 14, 2016 generated cross sections presented in Appendix B represent simplified configurations which were used in the analyses. The cross sections presented on Figures 2 and 3 are the original geologic sections from which the computer generated sections were derived. Table 2.3 presents the soil strength parameters that were utilized in the slope stability analyses. Shear strength parameters for our analysis were derived from the previous laboratory direct shear tests performed by GcoSoils and our experience and laboratory testing with similar soil types in the vicinity. It should be noted that the previous consultant used the "ultimate" strength value for Old Paralic Deposits based on their laboratory test results. It is our opinion that the "peak" value is more appropriate due to the granular nature of the material. Table 2.3 presents the soil strength parameters that were utilized in the slope stability analyses. TABLE 2.3 SOIL STRENGTH PARAMETERS Geologic Unit Angle of Internal Cohesion (psf) Friction~ (degrees) Compacted Fill 30 200 Old Paralic Deposits 32 200 Santiago Formation 37 300 3.0 Seismic Design Criteria We used the computer program U.S. Seismic Design Maps, provided by the USGS. Table 3.1 summarizes site-specific design criteria obtained from the 2013 California Building Code (CBC; Based on the 2012 International Building Code [IBC] and ASCE 7-10), Chapter 16 Structural Design, Section 1613 Earthquake Loads. The sh011 spectral response uses a period of 0.2 seconds. The values presented in Table 3.1 arc for the risk-targeted maximum considered earthquake (MCER). Based on soil conditions and planned grading, the building should be designed using a Site Class C. We evaluated the Site Class based on the discussion in Section 1613.3.2 of the 2013 CBC and Table 20.3- 1 of ASCE 7-10. Project No. G2037-32-0l - 4 -October 14, 2016 TABLE 3.1 2013 CBC SEISMIC DESIGN PARAMETERS Parameter Value 2013 CBC Reference Site Class C Section 1613.3.2 MCER Ground Motion Spectral 1.125g Figure 1613.3.1(1) Response Acceleration -Class B (short), Ss MCER Ground Motion Spectral 0.432g Figure 1613.3.1(2) Response Acceleration -Class B ( 1 sec), S 1 Site Coefficient, FA 1.000 Table 1613.3.3(1) Site Coefficient, F v 1.368 Table 1613.3.3(2) Site Class Modified MCER Spectral 1.125g Section 1613.3.3 (Eqn 16-37) Response Acceleration (short), SMs Site Class Modified MCER Spectral 0.591g Section 1613.3.3 (Eqn 16-38) Response Acceleration (I sec), SM1 5% Damped Design Spectral 0.750g Section 1613.3.4 (Eqn 16-39) Response Acceleration (short), SDs 5% Damped Design Spectral 0.394g Section 1613.3.4 (Eqn 16-40) Response Acceleration (I sec), S1J1 Table 3.2 presents additional se1sm1c design parameters for projects located in Seismic Design Categories of D through F in accordance with ASCE 7-10 for the mapped maximum considered geometric mean (MCEc; ). TABLE 3.2 2013 CBC SITE ACCELERATION PARAMETERS Parameter Value, Site Class C ASCE 7-10 Reference Mapped MCEG Peak Ground Acceleration, PGA 0.44g Figure 22-7 Site Coefficient, F PGA 1.00 Table 11.8-1 Site Class Modified MCEc; 0.44g Section 11.8.3 (Eqn 11.8-1) Peak Ground Acceleration, PGA,1 Conformance to the criteria for seismic design does not constitute any guarantee or assurance that significant structural damage or ground failure will not occur in the event of a maximum level earthquake. The primary goal of seismic design is to protect life and not to avoid all damage, since such design may be economically prohibitive. 4.0 Foundation and Concrete Slab-On-Grade Recommendations The following foundation recommendations are for proposed one-to three-story residential structures. The foundation recommendations have been separated into three categories based on either Project No. G2037-32-01 - 5 -October 14. 2016 the maximum and differential fill thickness or Expansion Index. The foundation category criteria arc presented in Table 4.1. Foundation Category I II III TABLE 4.1 FOUNDATION CATEGORY CRITERIA Maximum Fill Differential Fill Thickness, T (feet) Thickness, D (feet) T<20 -- 20:::T<SO 10:::0<20 T2:50 D>20 Expansion Index (El) El:::50 50<EI:::90 90<EI<l30 Final foundation categories for each building or lot will be provided after finish pad grades have been achieved and laboratory testing of the subgrade soil has been completed. Table 4.2 presents minimum foundation and interior concrete slab design criteria for conventional foundation systems. TABLE 4.2 CONVENTIONAL FOUNDATION RECOMMENDATIONS BY CATEGORY Foundation Minimum Footing Continuous Footing Interior Slab Category Embedment Depth Reinforcement Reinforcement (inches) I 12 Two No. 4 bars, 6 x 6 -10/10 welded wire one top and one bottom mesh at slab mid-point II 18 Four No. 4 bars, No. 3 bars at 24 inches on two top and two bottom center, both directions III 24 Four No. 5 bars, No. 3 bars at 18 inches on two top and two bottom center, both directions The embedment depths presented in Table 4.2 should be measured from the lowest adjacent pad grade for both interior and exterior footings. The conventional foundations should have a minimum width of 12 inches and 24 inches for continuous and isolated footings, respectively. A typical wall/column footing detail is presented on Figure 4. The concrete slabs-on-grade should be a minimum of 4 inches thick for Foundation Categories I and II and 5 inches thick for Foundation Category III. The concrete slabs-on-grade should be underlain by 4 inches and 3 inches of clean sand for 4-inch thick and 5-inch-thick slabs, respectively. Slabs expected to receive moisture sensitive floor coverings or used to store moisture sensitive materials should be underlain by a vapor inhibitor covered with at least 2 inches of clean sand or crushed rock. If Project No. G2037-32-01 - 6 -October 14, 2016 crushed rock will be used, the thickness of the vapor inhibitor should be at least 10 mil to prevent possible puncturing. As a substitute, the layer of clean sand ( or crushed rock) beneath the vapor inhibitor recommended in the previous section can be omitted if a vapor inhibitor that meets or exceeds the requirements of ASTM E 1745-97 (Class A), and that exhibits permeance not greater than 0.012 perm (measured in accordance with ASTM E 96-95) is used. This vapor inhibitor may be placed directly on properly compacted fill or formational materials. The vapor inhibitor should be installed in general confonnance with ASTM E 1643-98 and the manufacturer's recommendations. Two inches of clean sand should then be placed on top of the vapor inhibitor to reduce the potential for differential curing, slab curl, and cracking. Floor coverings should be installed in accordance with the manufacturer's recommendations. As an alternative to the conventional foundation recommendations, consideration should be given to the use of post-tensioned concrete slab and foundation systems for the support of the proposed structures. The post-tensioned systems should be designed by a structural engineer experienced in post-tensioned slab design and design criteria of the Post-Tensioning Institute (PTI), Third Edition, as required by the 2013 California Building Code (CBC Section 1808.6). Although this procedure was developed for expansive soil conditions, it can also be used to reduce the potential for foundation distress due to differential fill settlement. The post-tensioned design should incorporate the geotechnical parameters presented on Table 4.3 for the particular Foundation Category designated. The parameters presented in Table 4.3 are based on the guidelines presented in the PTI, Third Edition design manual. TABLE 4.3 POST-TENSIONED FOUNDATION SYSTEM DESIGN PARAMETERS Post-Tensioning Institute (PTI), Foundation Category Third Edition Design Parameters I II III Thomthwaite Index -20 -20 -20 Equilibrium Suction 3.9 3.9 3.9 Edge Lift Moisture Variation Distance. eM (feet) 5.3 5.1 4.9 Edge Lift, YM (inches) 0.61 I. I 0 1.58 Center Lift Moisture Variation Distance, eM (feet) 9.0 9.0 9.0 Center Lift, YM (inches) 0.30 0.47 0.66 Foundation systems for the lots that possess a foundation Category I and a "very low" expansion potential ( expansion index of 20 or less) can be designed using the method described in Section 1808 of the 2013 CBC. If post-tensioned foundations arc planned, an alternative, commonly Project No. G2037-32-01 -7 -October 14. 2016 accepted design method (other than PTI Third Edition) can be used. However, the post-tensioned foundation system should be designed with a total and differential deflection of 1 inch. Gcocon Incorporated should be contacted to review the plans and provide additional information, if necessary. The foundations for the post-tensioned slabs should be embedded in accordance with the recommendations of the structural engineer. If a post-tensioned mat foundation system is planned, the slab should possess a thickened edge with a minimum width of 12 inches and extend below the clean sand or crushed rock layer. If the structural engineer proposes a post-tensioned foundation design method other than PTI, Third Edition: • The deflection criteria presented in Table 4.3 are still applicable. • Interior stiffener beams should be used for Foundation Categories II and III. • The width of the perimeter foundations should be at least 12 inches. • The perimeter footing embedment depths should be at least 12 inches, 18 inches, and 24 inches for foundation categories I, II, and III, respectively. The embedment depths should be measured from the lowest adjacent pad grade. Our experience indicates post-tensioned slabs are susceptible to excessive edge lift, regardless of the underlying soil conditions. Placing reinforcing steel at the bottom of the perimeter footings and the interior stiffener beams may mitigate this potential. Current PTI design procedures primarily address the potential center lift of slabs but, because of the placement of the reinforcing tendons in the top of the slab, the resulting eccentricity after tensioning reduces the ability of the system to mitigate edge lift. The structural engineer should design the foundation system to reduce the potential of edge lift occurring for the proposed structures. During the construction of the post-tension foundation system, the concrete should be placed monolithically. Under no circumstances should cold joints be allowed to form between the footings/grade beams and the slab during the construction of the post-tension foundation system. Category I, II, or III foundations may be designed for an allowable soil bearing pressure of 2,000 pounds per square foot (psf) ( dead plus live load). This bearing pressure may be increased by one- third for transient loads due to wind or seismic forces. Isolated footings, if present, should have the mmunum embedment depth and width recommended for conventional foundations for a particular foundation category. The use of isolated footings, which are located beyond the perimeter of the building and support structural Project No. G2037-32-0I - 8 -October 14. 2016 clements connected to the building, are not recommended for Category III. Where this condition cannot be avoided, the isolated footings should be connected to the building foundation system with grade beams. For Foundation Category III, consideration should be given to using interior stiffening beams and connecting isolated footings and/or increasing the slab thickness. In addition, consideration should be given to connecting patio slabs, which exceed 5 feet in width, to the building foundation to reduce the potential for future separation to occur. Special subgrade prcsaturation is not deemed necessary prior to placing concrete; however, the exposed foundation and slab subgrade soil should be moisture conditioned, as necessary, to maintain a moist condition as would be expected in any such concrete placement. Where buildings or other improvements arc planned near the top of a slope steeper than 3: 1 (horizontal:vertical), special foundations and/or design considerations arc recommended due to the tendency for lateral soil movement to occur. • For fill slopes less than 20 feet high, building footings should be deepened such that the bottom outside edge of the footing is at least 7 feet horizontally from the face of the slope. • When located next to a descending 3: 1 (horizontal:vertical) fill slope or steeper, the foundations should be extended to a depth where the minimum horizontal distance is equal to H/3 (where H equals the vertical distance from the top of the fill slope to the base of the fill soil) with a minimum of 7 feet but need not exceed 40 feet. The horizontal distance is measured from the outer, deepest edge of the footing to the face of the slope. An acceptable alternative to deepening the footings would be the use of a post-tensioned slab and foundation system or increased footing and slab reinforcement. Specific design parameters or recommendations for either of these alternatives can be provided once the building location and fill slope geometry have been determined. • If swimming pools are planned, Gcocon Incorporated should be contacted for a review of specific site conditions. • Swimming pools located within 7 feet of the top of cut or fill slopes are not recommended. Where such a condition cannot be avoided, the portion of the swimming pool wall within 7 feet of the slope face be designed assuming that the adjacent soil provides no lateral support. This recommendation applies to fill slopes up to 30 feet in height, and cut slopes regardless of height. For swimming pools located near the top of fill slopes greater than 30 feet in height, additional recommendations may be required and Geocon Incorporated should be contacted for a review of specific site conditions. • Although other improvements, which arc relatively rigid or brittle, such as concrete flatwork or masonry walls, may experience some distress if located near the top of a slope, it is generally not economical to mitigate this potential. It may be possible, however, to Project No. G2037-32-01 - 9 -October 14. 2016 incorporate design measures, which would permit some lateral soil movement without causing extensive distress. Gcocon Incorporated should be consulted for specific recommendations. Exterior concrete flatwork not subject to vehicular traffic should be constructed in accordance with the recommendations herein. Slab panels should be a minimum of 4 inches thick and, when in excess of 8 feet square, should be reinforced with 6 x 6 -W2.9/W2.9 (6 x 6 -6/6) welded wire mesh or No. 3 reinforcing bars at 18 inches on center in both directions to reduce the potential for cracking. In addition, concrete flatwork should be provided with crack control joints to reduce and/or control shrinkage cracking. Crack control spacing should be determined by the project structural engineer based upon the slab thickness and intended usage. Criteria of the American Concrete Institute (ACI) should be taken into consideration when establishing crack control spacing. A 4-inch-thick slab should have a maximum joint spacing of 10 feet. Subgrade soil for exterior slabs not subjected to vehicle loads should be compacted in accordance with criteria presented in the grading section prior to concrete placement. Subgrade soil should be properly compacted and the moisture content of subgradc soil should be checked prior to placing concrete. The recommendations of this report are intended to reduce the potential for cracking of slabs due to expansive soil (if present), differential settlement of existing soil or soil with varying thicknesses. However, even with the incorporation of the recommendations presented herein, foundations, stucco walls, and slabs-on-grade placed on such conditions may still exhibit some cracking due to soil movement and/or shrinkage. The occurrence of concrete shrinkage cracks is independent of the supporting soil characteristics. Their occurrence may be reduced and/or controlled by limiting the slump of the concrete, proper concrete placement and curing, and by the placement of crack control joints at periodic intervals, in particular, where re-entrant slab corners occur. Geocon Incorporated should be consulted to provide additional design parameters as required by the structural engineer. 5.0 Top of Slope Walls/Fences Grade beam and/or caisson foundation systems are not considered necessary for retaining walls or fences proposed at the top of slope provided the recommendations of arc followed. 6.0 Grading and Foundation Plan Review The geotechnical engineer and engineering geologist should review the grading and foundation plans prior to final City submittal to check their compliance with the recommendations of this report and to dctenninc the need for additional comments, recommendations and/or analysis. Project No. G2037-32-0l -10 -October 14. 2016 Should you have any questions regarding this correspondence or desire additional information, please contact the undersigned. Very truly yours, GEOCON IN CORPORA TED Trevor Myers RCE 63773 TEM:DBE:dmc:ejc ( 3) Addressee Project No. G2037-32-01 -11 - . :.. .., ·····-"" . . Jt:,. ... David B.Evans¥ .if .... CEG 1860 October 14. 2016 .;:.c .',:; ,-:.;>: ,::,. '"'°" -/&,-EP: s+e().31 0 B A ----:·~ t:'.' ...!~-' {o! .. ~· /i:j ~-~ c-~ -~-~-c"--... ,·~~j"-:",,,"--~'-i~".--o ~-.... --------.. :',.-. -___ ,,_-';;:..Jl---.,;L.._ l'.1 -\\_ '~~~~~~~~~~~~ ,-1 1 ' ,I\IH--~~~~~ -,S-------,;-i--t~-f-'------,/-44)--ITI' ~G-:$--+ ~"I 5 99 -,------=--~-IL ,,, ,,, ,,: ~· o· o· SCALE 1·-60' {On 11x17) {i -_ tUAft~JY _!l_ ~ ·~ !!A 1+ GEOCON LEGEND DESIQ,I SPEED • 50 ~,..-..... f' GEOCON I ."l CO H. I' 0 HJ\ T ~: 1) ,~ 1v, ff SITE PLAN ROBERT MILES SUBDIVISION CARLSBAD, CALIFORNIA SCALE 1" : 6Q' DATE 10-14-2016 PROJECT NO. 02037 -32 -01 FIGURE GEOTEO-INiCAL CONSULT ANTS ~ 6960 FLANDERS DRIV£ SAN ~EGO, CALIFORNIA 91121 PHONE 858 558-6900 FAX 858 558 6159 2974 SHEET OF 1 5 1'£1KOO -~· ' I ' ,J ~--~r 1-,B-2 =-1~ •= .... ,., .. """ JO I'£ r•oo Fr!•,S ~1 L 1•, _ Di~ !f!.1f' H01' FOR SfllER, WATER AHO STREET MFRO\EMEH1S SE£ DM. Ha .f.96-6 b~A,lnc. lcn:I plcrnhg. cM engneemg. IU'M'jltlg 5115 /\VENIOA ENCINAS SUITE "L" CARLSBAD CA 9l008 4.387 (760) 9.3'-8100 '-\~:--: :,:·:~-~--~-: --+t : i" ,.~ B-3 ~ ........ APPROX.LOCATION OF EXPLORATORY BORING 1-4 BY GEOSOILS (2014) -$-...... .APPROX, LOCATION OF INFILTRATION TEST B B' . .APPROX. LOCATION OF GEOLOGIC CROSS -SECTION "AS BUILT" "'---Lle REVIEWED BY INSPECTOR DATE DATE [siiml CITY OF CARISBAD I SHEETS I f---1 +--1 +--1 ----+---1 +--1 +--1 +--ll I~ PLA!IS";;;~"'"G oee.,we,, B I ROBERT MILES SUBDIVISION I APPR0'£>: JASON s. GEl..OERT I r1---,1f--f-1--------------t1-:.,-"-1.r--.. -;-1-:;,.,-"----11-"---.. --;1 I~~ ~ii' '"';,~~2: I ~~:~-~~' DATE I NlW.. -~-REv1Sl0N DESCRIPTlON Plotted 1 0/13/20'6 9 41 AM I By RUBEN AGUILAR I File Location Y \PROJECTSIG2037-32·01 Miles Subdivision\SHEETS\G2037 ,32-01 SitePlan dwg ~ ....J Cl) ~ ~ z 0 I-<{ > w ....J w A A' 240-, r240 re STORMWA1ER LOT, LOT 11 · BASIN : LOT ---· -,-~] N I PR JECTED 220' 'i ' : AL G CONTOUR I PROPOSED GRADE .,)-~ ....J Cl) ~ ~ z ROBERT MILES SUBDIVISION CARLSBAD, CALIFORNIA 180--Qop 1-180 0 EXISTING GRADE Qop Tsa Tsa 120 ----'----r-~~~~r-~~~~r-~~~~r-~~~~~~~~~T--'--120 0 60 120 180 240 300 DISTANCE (FEET) GEOLOGIC CROSS-SECTION A-A' SCALE: 1" = 60' (Vert. = Horiz.) ~ w ....J w GEOCON LEGEND Qop ....... OLD PARALIC DEPOSITS Tsa ....... SANTIAGO FORMATION B-3 l ....... APPROX. LOCATION OF GEOTECHNICAL BORING GEOLOGIC CROSS -SECTION INCORPORATED ~ GE OCON GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE· SAN DIEGO, CALIFORNIA 92121 297 4 PHONE 858 558-6900 · FAX 858 558-6159 PROJECT NO. G2037 · 32 · 01 FIGURE 2 DATE 10 · 14 2016 PlottOO 1 0113/2016 12·33PM I By·RUBEN AGUILAR I File Location Y IPROJECTS\G2037 -32-01 Miles Subd,v,s1on\SHEETS\G203 1-32-01 Cross-Section dwg B B' 240---· -------------· ----------~240 STORMWATER ::i' t-----LOT_ BASIN " --LOT4 I /PR':~~~:~J I en ~ ~ z B-3 PRIVATE _j PROJiC.TED 50' r STREET • . ALONtj CONTOUR I -. 1---------------~XISTl~p--r180 Qop --, 180-1 0 I-<( > w __J Tsa I 1120 I w 120 ' Tsa ' ' 0 60 120 180 240 300 DISTANCE (FEET) GEOLOGIC CROSS-SECTION B-B' SCALE: 1" = 60' (Vert.= Horiz.) ~ __J en ~ ~ z 0 I-<( > w __J w ROBERT MILES SUBDIVISION CARLSBAD, CALIFORNIA GEOCON LEGEND Qop ....... OLD PARALIC DEPOSITS Tsa ...... sANTIAGo FORMATION B-3 l ........ APPROX. LOCATION OF GEOTECHNICAL BORING INCORPORATE[) ~ GEOCON GEOTECHNICAL • ENVIRONMENTAL • MATERIALS 6960 FLANDERS DRIVE· SAN DIEGO, CALIFORNIA 92121 297-4 PHONE 858 558-6900 · FAX 858 558-6159 PROJECT NO. G2037 · 32 · 01 GEOLOGIC CROSS -SECTION FIGURE 3 DATE 10 14 · 2016 Plotted 10113120'6 12·32PM I By RUBEN AGUILAR I File Location Y \PROJECTS\G2037 -32-01 M;les Subd1vts1on1SHEETS1G2037 32-D1 Cross-Section dwg CONCRETE SLAB ... PAD GRADE SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI YA//, SAND AND VAPOR RETARDER IN ACCORDANCE WITH ACI CONCRETE SLAB . . . GI ~ I-I-a. ow oo LJ.. , .. ··:· __l L """"/" j FOOTING* WIDTH .· . . . J ••• ~ . ,4 -"ct .,,<l.,Ll "',""-:=~ " .. . A . .. . ~ . ' . ". ·"<I'; >-------FOOTING WIDTH* --------i *.'".SEE REPORT FOR FOUNDATION WIDTH AND DEPTH RECOMMENDATION ' ' WALL/ COLUMN FOOTING DIMENSION DETAIL NO SCALE GEOCON INCORPORATED GEOTECHNICAL • ENVIRONMENTAL• MATERIALS 6960 FLANDERS DRIVE -SAN DIEGO, CALIFORNIA 92121-297 4 PHONE 858 558-6900 -FAX 858 558-6159 ROBERT MILES SUBDIVISION CARLSBAD I CALIFORNIA TM/CW DSK/GTYPD DATE 10 -14 -2016 I PROJECT NO. G2037 -32 -01 I FIG. 4 Plotted:10/13/2016 9:36AM I By:RUBEN AGUILAR I File Location:Y:\PROJECTS\G2037-32-01 Miles Subdivision\DETAILS\Wall-Column Footing Dimension Detail (COLFOOT2).dwg PPEN IX APPENDIX A RECOMMENDED GRADING SPECIFICATIONS FOR ROBERT MILES SUBDIVISION CT 14-04 CARLSBAD, CALIFORNIA PROJECT NO. G2037-32-01 RECOMMENDED GRADING SPECIFICATIONS 1. GENERAL 1.1 These Recommended Grading Specifications shall be used in conjunction with the Geotechnical Report for the project prepared by Gcocon. The recommendations contained in the text of the Geotcchnical Report arc a part of the ea1thwork and grading specifications and shall supersede the provisions contained hereinafter in the case of conflict. 1.2 Prior to the commencement of grading, a geotcchnical consultant (Consultant) shall be employed for the purpose of observing earthwork procedures and testing the fills for substantial conformance with the recommendations of the Geotcchnical Report and these specifications. The Consultant should provide adequate testing and observation services so that they may assess whether, in their opinion, the work was performed in substantial conformance with these specifications. It shall be the responsibility of the Contractor to assist the Consultant and keep them apprised of work schedules and changes so that personnel may be scheduled accordingly. 1.3 It shall be the sole responsibility of the Contractor to provide adequate equipment and methods to accomplish the work in accordance with applicable grading codes or agency ordinances, these specifications and the approved grading plans. If, in the opinion of the Consultant, unsatisfactory conditions such as questionable soil materials, poor moisture condition, inadequate compaction, and/or adverse weather result in a quality of work not in conformance with these specifications, the Consultant will be empowered to reject the work and recommend to the Owner that grading be stopped until the unacceptable conditions are c01rccted. 2. DEFINITIONS 2.1 Owner shall refer to the owner of the property or the entity on whose behalf the grading work is being performed and who has contracted with the Contractor to have grading performed. 2.2 Contractor shall refer to the Contractor performing the site grading work. 2.3 Civil Engineer or Engineer of Work shall refer to the California licensed Civil Engineer or consulting finn responsible for preparation of the grading plans, surveying and verifying as-graded topography. 2.4 Consultant shall refer to the soil engineering and engineering geology consulting firm retained to provide geotechnical services for the project. GI rev. 07/2015 2.5 Soil Engineer shall refer to a California licensed Civil Engineer retained by the Owner, who is experienced in the practice of geotcchnical engineering. The Soil Engineer shall be responsible for having qualified representatives on-site to observe and test the Contractor's work for conformance with these specifications. 2.6 Engineering Geologist shall refer to a California licensed Engineering Geologist retained by the Owner to provide geologic observations and recommendations during the site grading. 2.7 Geotechnical Report shall refer to a soil report (including all addenda) which may include a geologic reconnaissance or geologic investigation that was prepared specifically for the development of the project for which these Recommended Grading Specifications are intended to apply. 3. MATERIALS 3 .1 Materials for compacted fill shall consist of any soil excavated from the cut areas or imported to the site that, in the opinion of the Consultant, is suitable for use in construction of fills. In general, fill materials can be classified as soil fills, soil-rock fills or rock fills, as defined below. 3 .1.1 Soil fills are defined as fills containing no rocks or hard lumps greater than 12 inches in maximum dimension and containing at least 40 percent by weight of material smaller than% inch in size. 3.1.2 Soil-rock fills arc defined as fills containing no rocks or hard lumps larger than 4 feet in maximum dimension and containing a sufficient matrix of soil fill to allow for proper compaction of soil fill around the rock fragments or hard lumps as specified in Paragraph 6.2. Oversize rock is defined as material greater than 12 inches. 3.1.3 Rock fills are defined as fills containing no rocks or hard Jumps larger than 3 feet in maximum dimension and containing little or no fines. Fines are defined as material smaller than% inch in maximum dimension. The quantity of fines shall be less than approximately 20 percent of the rock fill quantity. 3.2 Material of a perishable, spongy, or othc1wise unsuitable nature as determined by the Consultant shall not be used in fills. 3 .3 Materials used for fill, either imported or on-site, shall not contain hazardous materials as defined by the California Code of Regulations, Title 22, Division 4, Chapter 30, Articles 9 GI rev. 07/2015 and 1 O; 40CFR; and any other applicable local, state or federal laws. The Consultant shall not be responsible for the identification or analysis of the potential presence of hazardous materials. However, if observations, odors or soil discoloration cause Consultant to suspect the presence of hazardous materials, the Consultant may request from the Owner the termination of grading operations within the affected area. Prior to resuming grading operations, the Owner shall provide a written report to the Consultant indicating that the suspected materials arc not hazardous as defined by applicable laws and regulations. 3.4 The outer 15 feet of soil-rock fill slopes, measured horizontally, should be composed of properly compacted soil fill materials approved by the Consultant. Rock fill may extend to the slope face, provided that the slope is not steeper than 2: 1 (horizontal:vcrtical) and a soil layer no thicker than 12 inches is track-walked onto the face for landscaping purposes. This procedure may be utilized provided it is acceptable to the governing agency, Owner and Consultant. 3.5 Samples of soil materials to be used for fill should be tested in the laboratory by the Consultant to determine the maximum density, optimum moisture content, and, where appropriate, shear strength, expansion, and gradation characteristics of the soil. 3.6 During grading, soil or groundwater conditions other than those identified in the Gcotechnical Report may be encountered by the Contractor. The Consultant shall be notified immediately to evaluate the significance of the unanticipated condition. 4. CLEARING AND PREPARING AREAS TO BE FILLED 4.1 Areas to be excavated and filled shall be cleared and grubbed. Clearing shall consist of complete removal above the ground surface of trees, stumps, brush, vegetation, man-made structures, and similar debris. Grubbing shall consist of removal of stumps, roots, buried logs and other unsuitable material and shall be performed in areas to be graded. Roots and other projections exceeding l 1/2 inches in diameter shall be removed to a depth of 3 feet below the surface of the ground. Bon-ow areas shall be grubbed to the extent necessary to provide suitable fill materials. 4.2 Asphalt pavement material removed during clearing operations should be properly disposed at an approved off-site facility or in an acceptable area of the project evaluated by Geocon and the property owner. Concrete fragments that arc free of reinforcing steel may be placed in fills, provided they are placed in accordance with Section 6.2 or 6.3 of this document. GI rev. 07/2015 4.3 After clearing and grubbing of organic matter and other unsuitable material, loose or porous soils shall be removed to the depth recommended in the Geotechnical Report. The depth of removal and compaction should be observed and approved by a representative of the Consultant. The exposed surface shall then be plowed or scari tied to a minimum depth of 6 inches and until the surface is free from uneven features that would tend to prevent uniform compaction by the equipment to be used. 4.4 Where the slope ratio of the original ground is steeper than 5:1 (horizontal:vertical), or where recommended by the Consultant, the original ground should be benched 111 accordance with the following illustration. TYPICAL BENCHING DETAIL Finish Grade Remove All Unsuitable Material As Recommended By Consultant Slope To Be Such That Sloughing Or Sliding Does Not Occur Original Ground Varies "B" See Note 1 See Note 2 No Scale DETAIL NOTES: (I) Key width "B" should be a minimum of 10 feet, or sufficiently wide to permit complete coverage with the compaction equipment used. The base of the key should be graded horizontal, or inclined slightly into the natural slope. (2) The outside of the key should be below the topsoil or unsuitable surficial material and at least 2 feet into dense formational material. Where hard rock is exposed in the bottom of the key, the depth and configuration of the key may be modified as approved by the Consultant. 4.5 After areas to receive fill have been cleared and scarified, the surface should be moisture conditioned to achieve the proper moisture content, and compacted as recommended in Section 6 of these specifications. GI rev. 07/2015 5. COMPACTION EQUIPMENT 5.1 Compaction of soil or soil-rock fill shall be accomplished by sheepsfoot or segmented-steel wheeled rollers, vibratory rollers, multiple-wheel pneumatic-tired rollers, or other types of acceptable compaction equipment. Equipment shall be of such a design that it will be capable of compacting the soil or soil-rock fill to the specified relative compaction at the specified moisture content. 5.2 Compaction of rock fills shall be performed in accordance with Section 6.3. 6. PLACING, SPREADING AND COMPACTION OF FILL MATERIAL 6.1 Soil fill, as defined in Paragraph 3.1.1, shall be placed by the Contractor in accordance with the following recommendations: 6.1.1 Soil fill shall be placed by the Contractor in layers that, when compacted, should generally not exceed 8 inches. Each layer shall be spread evenly and shall be thoroughly mixed during spreading to obtain uniformity of material and moisture in each layer. The entire fill shall be constructed as a unit in nearly level lifts. Rock materials greater than 12 inches in maximum dimension shall be placed in accordance with Section 6.2 or 6.3 of these specifications. 6.1.2 In general, the soil fill shall be compacted at a moisture content at or above the optimum moisture content as determined by ASTM D 1557. 6.1.3 When the moisture content of soil fill is below that specified by the Consultant, water shall be added by the Contractor until the moisture content is in the range specified. 6.1.4 When the moisture content of the soi/ fill is above the range specified by the Consultant or too wet to achieve proper compaction, the soil fill sha11 be aerated by the Contractor by blading/mixing, or other satisfactory methods until the moisture content is within the range specified. 6.1.5 After each layer has been placed, mixed, and spread evenly, it shall be thoroughly compacted by the Contractor to a relative compaction of at least 90 percent. Relative compaction is defined as the ratio (expressed in percent) of the in-place dry density of the compacted fill to the maximum laboratory dry density as determined in accordance with ASTM D 1557. Compaction shall be continuous over the entire area, and compaction equipment shall make sufficient passes so that the specified minimum relative compaction has been achieved throughout the entire fill. GI rev. 07/2015 6.1.6 Where practical, soils having an Expansion Index greater than 50 should be placed at least 3 feet below finish pad grade and should be compacted at a moisture content generally 2 to 4 percent greater than the optimum moisture content for the material. 6.1.7 Properly compacted soil fill shall extend to the design surface of fill slopes. To achieve proper compaction, it is recommended that fill slopes be over-built by at least 3 feet and then cut to the design grade. This procedure is considered preferable to track-walking of slopes, as described in the following paragraph. 6.1.8 As an alternative to over-building of slopes, slope faces may be back-rolled with a heavy-duty loaded sheepsfoot or vibratory roller at maximum 4-foot fill height intervals. Upon completion, slopes should then be track-walked with a D-8 dozer or similar equipment, such that a dozer track covers all slope surfaces at least twice. 6.2 Soil-rock fill, as defined in Paragraph 3.1.2, shall be placed by the Contractor in accordance with the following recommendations: 6.2.1 Rocks larger than 12 inches but less than 4 feet in maximum dimension may be incorporated into the compacted soil fill, but shall be limited to the area measured 15 feet minimum horizontally from the slope face and 5 feet below finish grade or 3 feet below the deepest utility, whichever is deeper. 6.2.2 Rocks or rock fragments up to 4 feet in maximum dimension may either be individually placed or placed in windrows. Under certain conditions, rocks or rock fragments up to IO feet in maximum dimension may be placed using similar methods. The acceptability of placing rock materials greater than 4 feet in maximum dimension shall be evaluated during grading as specific cases arise and shall be approved by the Consultant prior to placement. 6.2.3 For individual placement, sufficient space shall be provided between rocks to allow for passage of compaction equipment. 6.2.4 For windrow placement, the rocks should be placed in trenches excavated in properly compacted soil fill. Trenches should be approximately 5 feet wide and 4 feet deep in maximum dimension. The voids around and beneath rocks should be filled with approved granular soil having a Sand Equivalent of 30 or greater and should be compacted by flooding. Windrows may also be placed utilizing an "open-face" method in lieu of the trench procedure, however, this method should first be approved by the Consultant. GI rev. 07/2015 6.2.5 Windrows should generally be parallel to each other and may be placed either parallel to or perpendicular to the face of the slope depending on the site geometry. The minimum horizontal spacing for windrows shall be 12 feet center-to-center with a 5-foot stagger or offset from lower courses to next overlying course. The minimum vertical spacing between windrow courses shall be 2 feet from the top of a lower windrow to the bottom of the next higher windrow. 6.2.6 Rock placement, fill placement and flooding of approved granular soil m the windrows should be continuously observed by the Consultant. 6.3 Rock fills, as defined in Section 3.1.3, shall be placed by the Contractor in accordance with the following recommendations: 6.3.1 The base of the rock fill shall be placed on a sloping surface (minimum slope of 2 percent). The surface shall slope toward suitable subdrainage outlet facilities. The rock fills shall be provided with subdrains during construction so that a hydrostatic pressure buildup does not develop. The subdrains shall be permanently connected to controlled drainage facilities to control post-construction infiltration of water. 6.3.2 Rock fills shall be placed in lifts not exceeding 3 feet. Placement shall be by rock trucks traversing previously placed lifts and dumping at the edge of the currently placed lift. Spreading of the rock fill shall be by dozer to facilitate seating of the rock. The rock fill shall be watered heavily during placement. Watering shall consist of water trucks traversing in front of the current rock lift face and spraying water continuously during rock placement. Compaction equipment with compactive energy comparable to or greater than that of a 20-ton steel vibratory roller or other compaction equipment providing suitable energy to achieve the required compaction or deflection as recommended in Paragraph 6.3.3 shall be utilized. The number of passes to be made should be detennined as described in Paragraph 6.3.3. Once a rock fill lift has been covered with soil fill, no additional rock fill lifts will be permitted over the soil fill. 6.3.3 Plate bearing tests, in accordance with ASTM D 1196, may be performed in both the compacted soil fill and in the rock fill to aid in determining the required minimum number of passes of the compaction equipment. If performed, a minimum of three plate bearing tests should be performed in the properly compacted soil fill (minimum relative compaction of 90 percent). Plate bearing tests shall then be performed on areas of rock fill having two passes, four passes and six passes of the compaction equipment, respectively. The number of passes required for the rock fill shall be determined by comparing the results of the plate bearing tests for the soil fill and the rock fill and by evaluating the deflection GI rev. 07/2015 variation with number of passes. The required number of passes of the compaction equipment will be performed as necessary until the plate bearing deflections are equal to or less than that determined for the properly compacted soil fill. In no case will the required number of passes be less than two. 6.3.4 A representative of the Consultant should be present during rock fill operations to observe that the minimum number of "passes" have been obtained, that water is being properly applied and that specified procedures are being followed. The actual number of plate bearing tests will be determined by the Consultant during grading. 6.3.5 Test pits shall be excavated by the Contractor so that the Consultant can state that, in their opinion, sufficient water is present and that voids between large rocks are properly filled with smaller rock material. In-place density testing will not be required in the rock fills. 6.3.6 To reduce the potential for "piping" of fines into the rock fill from overlying soil fill material, a 2-foot layer of graded filter material shall be placed above the uppermost lift of rock fill. The need to place graded filter material below the rock should be determined by the Consultant prior to commencing grading. The gradation of the graded filter material will be determined at the time the rock fill is being excavated. Materials typical of the rock fill should be submitted to the Consultant in a timely manner, to allow design of the graded filter prior to the commencement of rock fill placement. 6.3.7 Rock fill placement should be continuously observed during placement by the Consultant. 7. SUBDRAINS 7.1 The geologic units on the site may have permeability characteristics and/or fracture systems that could be susceptible under certain conditions to seepage. The use of canyon subdrains may be necessary to mitigate the potential for adverse impacts associated with seepage conditions. Canyon subdrains with lengths in excess of 500 feet or extensions of existing offsitc subdrains should use 8-inch-diameter pipes. Canyon subdrains less than 500 feet in length should use 6-inch-diameter pipes. GI rev. 07/2015 TYPICAL CANYON DRAIN DETAIL ,·w.!'f.-ttt !lUl!!:)<WN !"Pf L .. ~, ~ SCHmll l!i:\ P'\IC .!>[JlFQRA'ftD f'lf'C FOO l'!LU, iN ~(Sil Of 100,.ff£1 li!,j OQ>TM Ok A Pll"C ;£NOTN Of u:miGtR ll'W( WO run ? Jl•INCIHJt~SCHt'.'.liffet ,t1l?\IC~1f0 l"i>f' FQA l'li.Ut U/SS '\'HM! 100$1.*T IN 0€?'\'h MA ?Pf UcNCifH ~q '1W\H !JOO ff!"\' BEDROCK !;lOW ~ tllJfJf1'11"1!•fOV'tlft. ~i llf ~O!AA'Xtl 'II coo,c !'UT! Foot t:I Ol"a! Cfi.>,/JiU:l GIIAW:a $~.)!ff !i<Sl<IVI 1Wffi:iO!li !'Qi\lfi/1, .. !':#H H."iil!.Mi!!l"IC NO SCALE 7.2 Slope drains within stability fill keyways should use 4-inch-diameter ( or lager) pipes. GI rev. 07/2015 TYPICAL STABILITY FILL DETAIL DETAIL C D<-.L'nlll\lO,Nll Wii!t ~= P~A$i!ICAJU) UffM!iC'f 1).-l'>Jll;l,l, \\\IR~ 0-\;Mlci;\l,,Nl,l,!Mi) 5PAC!itt:I ~1'lkV Jll tl!Ef tl\Hfllt 'Xi ce.t'®\ AHl'H !'Slit'l'WIOC ~ ~ w,y 9!t 1'!£00/Wro F ~n-,:?A.m: m fl'«'",t'"'I..Mrffl"f.~- ij, .,UJU!,ClOO-100C •+'I011'1'l!l\!lJMOWe1UlKRJ>ll!.11\I\IH>, tl-·-.U:P"',!t;m::i't()IJL[ lilt)'( tc:uw~1, M!OiiLC"'l!tl re e~ ><r, Ni~1' MW&¥ m ~'!RlClJ'!'l11 7.3 The actual subdrain locations will be evaluated in the field during the remedial grading operations. Additional drains may be necessary depending on the conditions observed and the requirements of the local regulatory agencies. Appropriate subdrain outlets should be evaluated prior to finalizing 40-scale grading plans. 7.4 Rock fill or soil-rock fill areas may require subdrains along their down-slope perimeters to mitigate the potential for buildup of water from construction or landscape irrigation. The subdrains should be at least 6-inch-diameter pipes encapsulated in gravel and filter fabric. Rock fill drains should be constructed using the same requirements as canyon subdrains. GI rev. 07/2015 7.5 Prior to outletting, the final 20-foot segment of a subdrain that will not be extended during future development should consist of non-perforated drainpipe. At the non-perforated/ perforated interface, a seepage cutoff wall should be constructed on the downslope side of the pipe. TYPICAL CUT OFF WALL DETAIL FRONT VIEW f.;;¢~~ *" C)/~ -Of,$. lA'm ~,.,.-S"·""" {~:.t'!'..(}1$fW~U 7.6 Subdrains that discharge into a natural drainage course or open space area should be provided with a permanent headwall structure. GI rev. 07/2015 TYPICAL HEADWALL DETAIL FRONT VIEW SIDE V!EW 001! ~k..i ~JH:f ffiml:1' A"r 'IT!!! Of fltl !LD<'t Oft !N'<P ca,.r~u;:;, ~MX UtM,,•.:;,c 7.7 The final grading plans should show the location of the proposed subdrains. After completion of remedial excavations and subdrain installation, the project civil engineer should survey the drain locations and prepare an "as-built" map showing the drain locations. The final outlet and connection locations should be determined during grading operations. Subdrains that will be extended on adjacent projects after grading can be placed on formational material and a vertical riser should be placed at the end of the subdrain. The grading contractor should consider videoing the subdrains shortly after burial to check proper installation and functionality. The contractor is responsible for the perfonnancc of the drains. GI rev. 0712015 8. OBSERVATION AND TESTING 8.1 The Consultant shall be the Owner's representative to observe and perform tests during clearing, grubbing, filling, and compaction operations. In general, no more than 2 feet in vertical elevation of soil or soil-rock fill should be placed without at least one field density test being performed within that interval. In addition, a minimum of one field density test should be performed for every 2,000 cubic yards of soil or soil-rock fill placed and compacted. 8.2 The Consultant should perform a sufficient distribution of field density tests of the compacted soil or soil-rock fill to provide a basis for expressing an opinion whether the fill material is compacted as specified. Density tests shall be perfonned in the compacted materials below any disturbed surface. When these tests indicate that the density of any layer of fill or portion thereof is below that specified, the paiiicular layer or areas represented by the test shall be reworked until the specified density has been achieved. 8.3 During placement of rock fill, the Consultant should observe that the minimum number of passes have been obtained per the criteria discussed in Section 6.3.3. The Consultant should request the excavation of observation pits and may perform plate bearing tests on the placed rock fills. The observation pits will be excavated to provide a basis for expressing an opinion as to whether the rock fill is properly seated and sufficient moisture has been applied to the material. When observations indicate that a layer of rock fill or any portion thereof is below that specified, the affected layer or area shall be reworked until the rock fill has been adequately seated and sufficient moisture applied. 8.4 A settlement monitoring program designed by the Consultant may be conducted in areas of rock fill placement. The specific design of the monitoring program shall be as recommended in the Conclusions and Recommendations section of the project Geotechnical Report or in the final report of testing and observation services perfonned during grading. 8.5 We should observe the placement of subdrains, to check that the drainage devices have been placed and constructed in substantial conformance with project specifications. 8.6 Testing procedures shall conform to the following Standards as appropriate: 8.6.1 Soil and Soil-Rock Fills: 8.6.1.1 Field Density Test, ASTM D 1556, Density al Soil In-Place By the Sand-Cone Method. GI rev. 07/2015 8.6.1.2 Field Density Test, Nuclear Method, ASTM D 6938, Density of Soil and Soil-Aggregate In-Place by Nuclear Methods (Shallow Depth). 8.6.1.3 Laboratory Compaction Test, ASTM D 1557, Moisture-Density Relations of Soils and Soil-Aggregate Mixtures Using 10-Pound Hammer and 18-lnch Drop. 8.6.1.4. Expansion Index Test, ASTM D 4829, Expansion Index Test. 9. PROTECTION OF WORK 9.1 During construction, the Contractor shall properly grade all excavated surfaces to provide positive drainage and prevent ponding of water. Drainage of surface water shall be controlled to avoid damage to adjoining properties or to finished work on the site. The Contractor shall take remedial measures to prevent erosion of freshly graded areas until such time as permanent drainage and erosion control features have been installed. Areas subjected to erosion or sedimentation shall be properly prepared in accordance with the Specifications prior to placing additional fill or structures. 9.2 After completion of grading as observed and tested by the Consultant, no further excavation or filling shall be conducted except in conjunction with the services of the Consultant. 10. CERTIFICATIONS AND FINAL REPORTS 10.1 Upon completion of the work, Contractor shall furnish Owner a certification by the Civil Engineer stating that the lots and/or building pads are graded to within 0.1 foot vertically of elevations shown on the grading plan and that all tops and toes of slopes are within 0.5 foot horizontally of the positions shown on the grading plans. After installation of a section of subdrain, the project Civil Engineer should survey its location and prepare an as-built plan of the subdrain location. The project Civil Engineer should verify the proper outlet for the subdrains and the Contractor should ensure that the drain system is free of obstructions. I 0.2 The Owner is responsible for furnishing a final as-graded soil and geologic report satisfactory to the appropriate governing or accepting agencies. The as-graded report should be prepared and signed by a California licensed Civil Engineer experienced in geotechnical engineering and by a California Certified Engineering Geologist, indicating that the geotechnical aspects of the grading were perfonned in substantial conformance with the Specifications or approved changes to the Specifications. GI rev. 07/2015 APPENDIX APPENDIX B SLOPE STABILITY ANALYSES FOR ROBERT MILES SUBDIVISION CT 14-04 CARLSBAD, CALIFORNIA PROJECT NO. G2037-32-01 GEC)CC)N Seismic Slope Stability Evaluation Input Data in Shaded Areas Project Miles Subdivision Project Number G2037-32-01 Date 09/27 /16 Filename AA-Case1 Computed By TEM Peak Ground Acceleration (Firm Rock), MHA,, g Modal Magnitude, M 0.23 10% in 50 years 6.8 Modal Distance, r, km 9:2 1 Site Condition, S (0 for rock, 1 for soil) Yield Acceleration, kyfg NA <--Enter Value or NA for Screening Analysis Shear Wave Velocity, V, (ft/sec) NA <-- Max Vertical Distance, H (Feet) NA <-- Is Slide X-Area > 25,000ft2 (Y/N) Correction for horizontal incoherence Duration, D5_95lm,d, sec rf <--Use "N" for Buttress Fills Coefficient, C1 Coefficient, C2 Coefficient, C3 Standard Error, £T Mean Square Period, Tm, sec Initial Screening with MHEA = MHA = kmax9 1.0 11.535 0.5190 0.0837 0.0019 0437 0.602 ~~ ~ fEO(u=5cm) = (NRF/3.477)'(1.87-log(u/((MHA/g)'NRF'D5_95))) 0.5599 km= feq(MHAr)/g 0.129 Factor of Safety in Slope Analysis Using kEO 1.20 Passes Initial Screening Analysis Approximation of Seismic Demand Period of Sliding Mass, T, = 4HN 5, sec T/Tm MHEA/(MHA'NRF) NRF = 0.6225+0.9196EXP(-2.25'MHA/g) MHEA/g NA NA NA 1.17 NA k/MHEA = k/kmax NA Normalized Displacement, Normu NA Estimated Displacement, u (cm) NA Figure B-3 GEC:)CON Seismic Slope Stability Evaluation Input Data in Shaded Areas Project Miles Subdivision Project Number G2037-32-01 Date 09/27/16 Filename BB-Case1 Computed By TEM Peak Ground Acceleration (Firm Rock), MHA,, g Modal Magnitude, M 0,23 10% in 50 years 6,8 Modal Distance, r, km 9.2 1 Site Condition, S (0 for rock, 1 for soil) Yield Acceleration, kJg NA <--Enter Value or NA for Screening Analysis Shear Wave Velocity, V5 (ft/sec) NA <-- Max Vertical Distance, H (Feet) NA <-- Is Slide X-Area > 25.000ft2 (Y/N) Correction for horizontal incoherence Duration, D5.9slmed, sec N <--Use "N" for Buttress Fills Coefficient, C1 Coefficient, C2 Coefficient, C3 Standard Error, "T Mean Square Period, Tm, sec Initial Screening with MHEA = MHA = kmax9 1.0 11.535 0.5190 0.0837 0.0019 0.437 0.602 ~~ ~ fm(u=5cm) = (NRF/3.477)'(1.87-log(u/((MHA/g)'NRF'D5.95))) 0.5599 km= feq(MHA,)/g 0.129 Factor of Safety in Slope Analysis Using km 1.60 Passes Initial Screening Analysis Approximation of Seismic Demand Period of Sliding Mass, T5 = 4HN5, sec T/Tm MHEA/(MHA'NRF) NRF = 0.6225+0.9196EXP(-2.25'MHA/g) MHEA/g NA NA NA 1.17 NA kJMHEA = k,ikm,, NA Normalized Displacement, Normu NA Estimated Displacement, u (cm) NA Figure B-6 APPENDIX APPENDIX C STORM WATER MANAGEMENT FOR ROBERT MILES SUBDIVISION CT 14-04 CARLSBAD, CALIFORNIA PROJECT NO. G2037-32-01 APPENDIX C STORM WATER MANAGEMENT INVESTIGATION We understand storm water management devices are being proposed in accordance with the 2016 Model BMP Design Manual, San Diego Region, commonly referred to as the Storm Water Standard~ (SWS). If not properly constructed, there is a potential for distress to improvements and properties located hydrologically down gradient or adjacent to these devices. Factors such as the amount of water to be detained, its residence time, and soil penneability have an important effect on seepage transmission and the potential adverse impacts that may occur if the storm water management features are not properly designed and constructed. We have not performed a hydrogcological study at the site. If infiltration of storm water runoff occurs, downstream properties may be subjected to seeps, springs, slope instability, raised groundwater, movement of foundations and slabs, or other undesirable impacts as a result of water infiltration. Hydrologic Soil Group The United States Department of Agriculture (USDA), Natural Resources Conservation Services, possesses general information regarding the existing soil conditions for areas within the United States. The USDA website also provides the Hydrologic Soil Group. Table C-1 presents the descriptions of the hydro logic soil groups. If a soil is assigned to a dual hydrologic group (AID, BID, or CID), the first letter is for drained areas and the second is for undrained areas. In addition, the USDA website also provides an estimated saturated hydraulic conductivity for the existing soil. TABLE C-1 HYDROLOGIC SOIL GROUP DEFINITIONS Soil Group Soil Group Definition Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These A consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of B moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils C having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These D consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. Project No. G2037-32-01 -C-1 -October 14, 2016 The property is underlain by 3 units identified as Carlsbad gravelly loamy sand (CbC), Maira loamy coarse sand (MIC), and Marina loamy coarse sand (MIE). The Carlsbad gravelly loamy sand and marina loamy coarse sand is classified as Soil Group B. Table C-2 presents the information from the USDA website for the subject property. TABLE C-2 USDA WEB SOIL SURVEY -HYDROLOGIC SOIL GROUP Map Unit Approximate Hydro logic ksAT of Most Map Unit Name Percentage Limiting Layer Symbol of Property Soil Group (inches/hour) Carlsbad gravelly loamy sand CbC 44.8 B 1.98-5.95 Marina loamy coarse sand MIC 23.5 B 0.57 -1.98 Marina loamy coarse sand MIE 31.7 B 0.57 -1.98 In-Situ Testing The infiltration rate, percolation rates and saturated hydraulic conductivity are different and have different meanings. Percolation rates tend to overestimate infiltration rates and saturated hydraulic conductivities by a factor of l O or more. Table C-3 describes the differences in the definitions. TABLE C-3 SOIL PERMEABILITY DEFINITIONS Term Definition The observation of the flow of water through a material into the ground Infiltration Rate downward into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space. discontinuities and initial moisture content. The observation of the flow of water through a material into the ground Percolation Rate downward and laterally into a given soil structure under long term conditions. This is a function of layering of soil, density, pore space, discontinuities and initial moisture content. The volume of water that will move in a porous medium under a Saturated Hydraulic hydraulic gradient through a unit area. This is a function of density, Conductivity (ksAT, Permeability) structure, stratification, fines content and discontinuities. It is also a function of the properties of the liquid as well as of the porous medium. The degree of soil compaction or in-situ density has a significant impact on soil permeability and infiltration. Based on our experience and other studies we performed, an increase in compaction results in a decrease in soil permeability. Project No. G2037-32-0l -C-2 -October 14. 2016 We performed 4 Aardvark Pcrmeametcr Tests, 1-1 through 1-4, at locations shown on the attached Site Plan, Figure 1. The test borings were 4 inches in diameter. The results of the tests provide parameters regarding the saturated hydraulic conductivity characteristics of on-site soil and geologic units. Table C-4 presents the results of the estimated field saturated hydraulic conductivity and estimated infiltration rates obtained from the Aardvark Penneametcr tests. The field sheets are also attached herein. We applied a feasibility factor of safety of 2 to the field results for use in preparation of Worksheet C.4-1. The results of the testing within old paralic deposits indicate an adjusted soil infiltration rate ranging between 0.08 and 0.65 inches per hour after applying a Factor of Safety of 2. Based on a discussion in the County of Riverside Design Handbook for Low Impact Development Best Management Practices, the infiltration rate should be considered equal to the saturated hydraulic conductivity rate. TABLE C-4 FIELD PERMEAMETER INFILTRATION TEST RESULTS Geologic Test Depth Field-Saturated Worksheet1 Saturated Test No. Hydraulic Conductivity, Hydraulic Conductivity, Unit (feet) ksat (inch/hour) ksat (inch/hour) I-1 Qop 2.7 0.68 0.34 I-2 Qop 2.7 0.25 0.13 I-3 Qop 4.7 1.3 0.65 1-4 Qop 4.0 0.16 0.08 1 Using a factor of safety of 2 for Worksheet C .4-1. STORM WATER MANAGEMENT CONCLUSIONS The Site Plan, Figure 1, depicts the existing property, proposed conceptual development and the in- situ infiltration test locations. Soil Types Proposed Compacted Fill -Compacted fill will be placed across the entire property during site development. Proposed remedial grading will consist of removing any undocumented fill, colluvium, and weathered old paralic deposits and replacement as compacted fill. The proposed storm water BMP's will be founded in compacted fill placed above dense to very dense old paralic deposits. The compacted fill will be comprised of the on-site silty/clayey sands. The fill will be compacted to a dry density of at least 90 percent of the laboratory maximum dry density. In our experience, compacted fill does not possess infiltration rates appropriate for infiltration BMP' s. Hazards that occur as a result of fill soil saturation include a potential for hydro-consolidation of the granular fill soils, long term fill settlement, differential fill settlement, and lateral movement associated with saturated fill relaxation. The potential for lateral water migration to adversely impact existing or proposed Project No. G2037-32-01 -C-3 -October 14. 2016 structures, foundations, utilities, and roadways, is high. Therefore, full and partial infiltration should be considered infeasible. Section D.4.2 of the 2016 Storm Water Standards (SWS) provides a discussion regarding fill materials used for infiltration. The SWS states: • For engineered fills, infiltration rates may still be quite uncertain due to layering and heterogeneities introduced as part of construction that cannot be precisely controlled. Due to these uncertainties, full and partial infiltration should be considered geotechnically infeasible and liners and subdrains should be used in areas where infiltration BMP's arc founded in compacted fill. • Where possible, infiltration BMPs on fill material should be designed such that their infiltrating surface extend1· into native soils. The underlying granitic rock below the compacted fill is expected between 5 to 30 feet below proposed finish grades after remedial grading is performed. Full and partial infiltration should be considered geoteehnically infeasible within the compacted fill and liners and subdrains should be used. Ifthc infiltration BMP's extended below the compacted fill, partial infiltration may be feasible. • Because of the uncertainty offill parameters as well as potential compaction of the native soils, an infiltration BMP may not be feasible. Therefore, full and partial infiltration should be considered geotechnically infeasible and liners and subdrains should be used in the fill areas. • If the source offt!l materia/ is defined and this material is known to be of a granular nature and that the native soils below are permeable and will not be highly compacted, infiltration through compacted fill materials may still he feasible. In this case. a project phasing approach could he used including the following general steps, (I) collect samplesji-0111 areas expected to be used for .fill, (2) remold samples to approximately the proposed degree o{ compaction and measure the saturated hydraulic conductivity of remolded samples using laboratory methods, (3) if infiltration rates appear adequate for infiltration, then apply an appropriate factor of safety and use the initial rates for preliminmy design, (4) following placement of.fill, conduct in-situ testing to refine design infiltration rates and adjust the design as needed. However, based on the discussion above, it is our opinion that infiltrating into compacted fill should be considered geotechnically infeasible and liners and subdrains should be used. Infiltration Rates The results of the infiltration rates obtained within the old paralic deposits ranged between 0.08 and 0.65 inches per hour. Three of the four tests indicated adjusted infiltration rates below the current threshold for infiltration BMP's. Test No. I-3 which yielded an adjusted rate of 0.65 inches per hour was not considered representative of the dense to very dense old paralic deposits observed in the other tests. Therefore, based on the results of the infiltration testing, full infiltration should be considered infeasible. Project No. G2037-32-01 -C-4 -October 14. 2016 Groundwater Elevations Groundwater was not encountered during the subsurface exploration. Groundwater is not expected to be a geotechnical constraint. We expect to encounter groundwater at elevations near sea level, or greater than 100 feet below the ground surface. Soil or Groundwater Contamination Soil or groundwater contamination is not expected. New or Existing Utilities Existing utilities are present within right of ways adjacent to the existing streets, generally beneath sidewalks and roadways. We expect that all on-site utilities would be removed prior to site development. Full or partial infiltration near existing or proposed utilities should be avoided to prevent lateral water migration into the permeable trench backfill materials. Existing and Planned Structures Residential developments exist to the north, west, and south. Public streets are located immediately adjacent to the northern and southern property boundaries. An existing residence is located in close proximity to the western property boundary. If water is allowed to infiltrate into the soil, the water could migrate laterally and into other properties in the vicinity of the subject site. The water migration may negatively affect other buildings and improvements in the area. Slopes and Other Geologic Hazards An approximately 60-foot high slope descends from the site to Monroe Street. The slope stability analyses without pore water pressure/perched groundwater indicates a factor of safety of 1.5 along Cross-Section A-A'. If water is allowed to infiltrate into the slope zone soils, slope instability may be experienced. Full or partial infiltration should be avoided to prevent lateral water migration, daylight water seepage, and slope instability. Recommendations Liners and subdrains should be incorporated into the design and construction of the planned storm water devices. The liners should be impermeable (e.g. High-density polyethylene, HOPE, with a thickness of about 30 mil or equivalent Polyvinyl Chloride, PVC) to prevent water migration. The subdrains should be perforated within the liner area, installed at the base and above the liner, be at least 3 inches in diameter and consist of Schedule 40 PVC pipe. The subdrains outside of the liner should consist of solid pipe. Scams and penetrations of the liners should be properly waterproofed. Project No. G2037-32-0l -C-5 -October 14, 2016 The subdrains should be connected to a proper outlet. The devices should also be installed m accordance with the manufacturer's recommendations. Storm Water Standard Worksheets The SWS requests the geotechnical engineer complete the Categorization of Infiltration Feasibility Condition (Worksheet C.4-1 or I-8) worksheet information to help evaluate the potential for infiltration on the property. The attached Worksheet C.4-1 presents the completed information for the submittal process. The regional storm water standards also have a worksheet (Worksheet D.5-1 or Form I-9) that helps the project civil engineer estimate the factor of safety based on several factors. Table C-5 describes the suitability assessment input parameters related to the geotechnical engineering aspects for the factor of safety determination. TABLE C-5 SUITABILITY ASSESSMENT RELATED CONSIDERATIONS FOR INFILTRATION FACILITY SAFETY FACTORS Consideration High Medium Low Concern -3 Points Concern - 2 Points Concern - 1 Point Use of soil survey maps Use of well permeameter or simple texture or borehole methods with Direct measurement analysis to estimate accompanying continuous with localized short-term infiltration boring log. Direct (i.e. small-scale) rates. Use of well measurement of infiltration testing Assessment Methods pem1eameter or borehole infiltration area with methods at relatively methods without localized infiltration high resolution or use accompanying measurement methods of extensive test pit continuous boring log. ( e.g., Infiltrometer). infiltration Relatively sparse testing Moderate spatial measurement with direct infiltration methods. methods resolution Predominant Soil Texture Silty and clayey soils Loamy soils Granular to slightly with significant fines loamy soils Highly variable soils Soil boring/test pits Soil boring/test pits indicated from site Site Soil Variability assessment or unknown indicate moderately indicate relatively variability homogenous soils homogenous soils Depth to Groundwater/ <5 feet below 5-15 feet below > 15 feet below Impervious Layer facility bottom facility bottom facility bottom Based on our geotechnical investigation and the Table C-5, Table C-6 presents the estimated factor values for the evaluation of the factor of safety. This table only presents the suitability assessment Project No. G2037-32-0l -C-6 -October 14. 2016 safety factor (Part A) of the worksheet. The project civil engineer should evaluate the safety factor for design (Part B) and use the combined safety factor for the design infiltration rate. TABLE C-6 FACTOR OF SAFETY WORKSHEET DESIGN VALUES-PART A1 Suitability Assessment Factor Category Assigned Factor Product Weight (w) Value (v) (p = W XV) Assessment Methods 0.25 3 0.75 Predominant Soil Texture 0.25 2 0.50 Site Soil Variability 0.25 2 0.50 Depth to Groundwater/ Impervious Layer 0.25 1 0.25 Suitability Assessment Safety Factor, SA= LP 2.00 1 The project civil engineer should complete Worksheet D.5-1 or Form 1-9 using the data on this table. Additional information is required to evaluate the design factor of safety. Project No. G2037-32-01 -C-7 -October 14. 2016 Appendix I: Forms and Checklists 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 Yes No Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this X Screening Question shall be based on a comprchensi\-e evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Based on results of permeability testing in four locations within the underlying old paralic deposits, the unfactored infiltration rate was measured to be 0.68, 0.25, 1.3, and 0.16 inches/hour using a constant head borehole pem1eameter. If applying a feasibility factor of safety of 2.0, the infiltration rates would be 0.34 iph, 0.13 iph, 0.65 iph, and 0.08 iph. Therefore, 3 of the 4 tests did not meet the minimum threshold for infiltration feasibility. The test that did meet the criteria was not considered representative of the dense to very dense old paralic deposits. The Aardvark Permeameter test results are attached. In accordance with the Riverside County storm water procedures, which reference the United States Bureau of Reclamation Well Permeameter Method (USBR 7300), the saturated hydraulic conductivity is equal to the unfactored infiltration rate. 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. X Provide basis: .-\n approximately 60-foot high slope descends from the propertv to i\!onroe Street. Based on the results of slope stabilitv anah·ses, the slope exhibits a factor of safetv of 1.5 without any pore water pressure/perched groundwater. If water is allowed to infiltrate near this slope, daylight seepage and slope instabilitv mav be experienced. Existing public streets are situated to the north and south of the property. An existing residence exists immediateh· to the west of the site. \'(ater infiltration may result in lateral water migration that may adversely impact existing public utilities. Along the western property boundarv, water infiltration may result in davlight water seepage and potential distress to the existing residence. 1-27 February 2016 Criteria 3 Appendix I: Forms and Checklists 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 shall be based on a comprehensive e\-aluation of the factors presented in 1\ppcndix C.3. Yes No X Prcwide basis: Groundwater is not located within IO feet from any proposed infiltration BMP, therefore the risk of storm water infiltration BM P's adversely impacting groundwater is considered negligible. Based on the Geotracker website, no known active remediation sites exist in the vicinity of the site. 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 shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. X Pro\-ide basis: We are not aware of any wells within I 00 feet of the site, and given the amount of water that would infiltrate into the ground, it is our opinion there are no adverse impacts to groundwater, water balance impacts to stream flow, or impacts on any downstream water rights. It should be noted that researching downstream water rights or evaluating water balance issues to stream flows is beyond the scope of the geotechnical consultant. Part 1 Result * If all ans,\-ers to ro\\'S 1 - 4 arc "Yes" a full infiltration design is potentially feasible.The feasibilin-screening categon· is Full Infiltration If am· 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 No ~To be completed using gathered site information and best professional judgment considering the definition of J\IEP in the .\fS4 Permit. Additional testing and/ or studies ma\-be reyuired by A.genC\ /Jurisdictions to substantiate findings 1-28 February 2016 Appendix I: Forms and Checklists Part 2 -Partial lnf'tltration vs. No Infiltration Feasibility ScreeningCriteria Would infiltration of water in any appreciable amount be 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 shall be based on a cornprehensiYe e,-aluation of the factors presented in Appendix C.2 and ,\ppendix D. Yes No X PrnYide basis: Any infiltration Bi\f P's would be founded in either compacted fill or dense to \Tr\' dense old paralic deposits. Infiltration Bi\TP' s founded in compacted fill arc not recommended due to the potential for lateral water migration, hydro-comolidation, and differential settlement. Infiltration Bi\fP's founded in the underlying old paralic deposits may also result in lateral water migration, daylight water seepage and slope instabilit\'. Please refer to discussion in Appendix C. Slope stability analyses indicate factors of safet\' below current standards of 1.5 under static conditions if water is allmYed to infiltrate into the slope zone soils. 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 comprehensi,-e eya]uation of the factors presented in Appendix C:.2. X Prm-ide basis: /rn approximate!\· 60-foot high slope descends from the property to 1\lonme Street. Based on the results of slope stability anal\'ses, the slope exhibits a factor of safet\' of 1.5 without any pore water pressure/perched groundwater. If water is allowed to infiltrate near this slope, daylight seepage and slope instability ma,· be experienced. Existing public streets are situated to the north and south of the propert\'. An existing residence exists immediate!\' to the west of the sit<:. \X'ater infiltration may result in lateral water mi,L,'1'ation that may ad,-ersch· impact existing public utilities. Along the western property buundan-, water infiltration ma\' result in dm·light water seepage and potential distress to the existing residence. 1-29 February 2016 Criteria 7 Appendix I: Forms and Checklists 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 shall be based on a comprehensive cnluation of the factors presented in Appendix C.3. Yes No X Prnvide basis: Groundwater is not located within 10 feet from any proposed infiltration BMP, therefore the risk of storm water infiltration BMP's adversely impacting groundwater is considered negligible. Based on the Geotracker website, no known active remediation sites exist in the vicinity of the site. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Qm:stion shall be based ona comprehensi\-e ffaluation of the factors presented in .\ppendix C.3. X Provide basis: We are not aware of any wells within l 00 feet of the site, and given the amount of water that would infiltrate into the ground, it is our opinion there are no adverse impacts to groundwater, water balance impacts to stream flow, or impacts on any downstream water rights. It should be noted that researching downstream water rights or evaluating water balance issues to stream flows is beyond the scope of the geotechnical consultant. Part 2 Result* If all answers from row 5-8 are \·cs then partial infiltration design is potentiall\-feasible. The feasibilin· screening category is Partiallnfiltration. If any answer from row 5-8 is no, then infiltration of any \'olume is considered to be infeasible within the drainage area. The feasibilin-screening category is No Infiltration. No Infiltration *To be completed ming gathered site information and best professional judgment considering the definition of i\lEP in the i\lS4 Permit. .\dditional testing and/ or studies mav be reyuircd b,· .\gcncv /Jurisdictions to substantiate findings 1-30 February 2016 G·EOCC)N Aardvark Permeameter Data Analysis Project Name: ___ M--,il_es_su __ b_d_i_v_is_io_n __ _ Project Number: G2037-32-01 Date: 9/28/2016 By: TM ------------------- Bore ho I e Location: 1-1 Ref. EL (feet, MSL): ------- Borehole Diameter (inches) Borehole Depth, H (feet) 4.00 2.67 Bottom EL (feet, MSL): ------- Wetted Area, A (in2):!.___---'8;..;3'-.8.c..1"------' Distance Between Reservoir & Top of Borehole (feet) 2.33 Reading 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 C: 0 ·z-a. C: E .E ::, ....... VIM C: C: 0 ==-u ~ 2l ra ra er: 3: Depth to Water Table, s (feet) Height APM Raised from Bottom (inches) 100 2.00 Distance Between Resevoir and APM, D (feet): Head Height, h (inches): Distance Between Constant Head and Water Table, L (inches): Time Time Elapsed Reservoir Water Resevoir Water Interval Water (min) Weight (g) Weight (lbs) Consumption (lbs) (min) 0.00 22.800 15.00 15.00 21.185 1.62 25.00 10.00 20.300 0.88 35.00 10.00 19.430 0.87 45.00 10.00 18.620 0.81 55.00 10.00 17.830 0.79 65.00 10.00 17.020 0.81 75.00 10.00 16.235 0.79 85.00 10.00 15.415 0.82 95.00 10.00 14.635 0.78 4.23 5.67 1174 *Water Total Water Consumption Rate Consumption (lbs) (in3/min) 1.62 2.98 2.50 2.45 3.37 2.41 4.18 2.25 4.97 2.19 5.78 2.25 6.57 2.18 7.39 2.27 8.17 2.16 Steady Flow Rate, Q (in3/min): 2.16 4.00 3.00 2.00 1.00 0.00 0 10 20 30 40 ··········································"" 50 Time (min) >·w~-••••"" 60 Field-Saturated Hydraulic Conductivity -Infiltration Rate Case 1: L/h > 3 K,at = ~--0_.0_1_1_3_~1 in/min ·····"'······"'"'"""""' ''""'"""-""'""' 70 80 90 .___ __ o_. 6_s __ __.l in/hr 100 G-EOCC)N Aardvark Permeameter Data Analysis Project Name: Miles Subdivision Date: 9/28/2016 -----------Project Number: ____ G_2_0_3_7_-3_2_-_0l ___ _ By: ___ T_M ___ _ Borehole Location: 1-2 Borehole Diameter (inches) Borehole Depth, H (feet) Distance Between Reservoir & Top of Borehole (feet) Depth to Water Table, s (feet) Height APM Raised from Bottom (inches) Ref. EL (feet, MSL): Bottom EL (feet, MSL): 4.00 2.67 2.42 100 2.00 Distance Between Resevoir and APM, D (feet): Head Height, h (inches): Distance Between Constant Head and Water Table, L (inches): -------- -------- Wetted Area, A (in2):._! ___ 8;...3;...._8_S __ _, 4.32 5.67 1174 Time *Water Reading 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 C: 0 ·.;;-a. C: E ·- ::i ~ "' ~ C: C: 0:::. u QJ ....... QJ "' "lu a: ~ Time Elapsed Reservoir Water Resevoir Water Interval Water Total Water Consumption Rate (min) Weight (g) Weight (lbs) Consumption (lbs) Consumption (lbs) 0.00 10.00 20.00 31.00 41.00 51.00 61.00 71.00 81.00 92.00 102.00 1.50 1.00 0.50 0.00 0 (min) (in3/min) 24.130 10.00 23.690 0.44 0.44 1.22 10.00 23.310 0.38 0.82 1.05 11.00 22.945 0.36 1.19 0.92 10.00 22.655 0.29 1.48 0.80 10.00 22.340 0.32 1. 79 0.87 1000 22.005 0.34 2.13 0.93 10.00 21.685 0.32 2.45 0.89 10.00 21.370 0.31 2.76 0.87 11.00 21.040 0.33 3.09 0.83 10.00 20.750 0.29 3.38 0.80 Steady Flow Rate, Q (in3/min): 0.80 T ·············--···""'I". --......__ ~--~;;....;:;~::::~;;;;;;;;~;.;;;;;;;,;;;;.t;;;;;;:;;;;;;;;,;~·····~i:.:..:::::;:::::::: 1 .. _.__._..{-. __ __ 10 20 30 40 50 60 70 80 90 100 Time (min) 110 Field-Saturated Hydraulic Conductivity -Infiltration Rate Case 1: L/h > 3 K,ar = .__ __ o_.o_o_4_2 _ __,! in/min ..._ __ o_.2_s __ __.! in/hr G-EOCON Aardvark Permeameter Data Analysis Project Name: Miles Subdivision Date: 9/28/2016 -----------Project Number: G2037-32-01 By: TM ------------------- Bore ho I e Location: 1-3 Ref. EL (feet, MSL): ------- Bottom EL (feet, MSL): -------- 4.00 Borehole Diameter (inches) Borehole Depth, H (feet): 4.67 Wetted Area, A (in'l:._! ___ 8_4_._8_1 __ _. Distance Between Reservoir & Top of Borehole (feet) 2.33 Depth to Water Table, s (feet) 100 Height APM Raised from Bottom (inches) 2.00 Distance Between Resevoir and APM, D (feet): 6.23 Head Height, h (inches): 5.75 Distance Between Constant Head and Water Table, L (inches): 1150 Time *Water Reading Time Elapsed Reservoir Water Resevoir Water Interval Water Total Water Consumption Rate (min) (min) Weight (g) Weight (lbs) Consumption (lbs) Consumption (lbs) (in3/min) 1 0.00 23.560 2 10.00 10.00 21.365 2.20 2.20 6.08 3 21.00 11.00 19.300 2.07 4.26 5.20 4 30.00 9.00 17.720 1.58 5.84 4.87 5 45.00 15.00 15.170 2.55 8.39 4.71 6 55.00 10.00 13.555 1.62 10.01 4.48 7 65.00 10.00 11.975 1.58 11.59 4.38 8 75.00 10.00 10.395 1.58 13.17 4.38 9 85.00 10.00 8.875 1.52 14.69 4.21 10 95.00 10.00 7.355 1.52 16.21 4.21 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Steady Flow Rate, Q (in3 /min): 4.21 C: 0 :;;-a. C: E ·- :::i !. V, M C: C: 0 ::=. u cu ,._ ... 2"' "'er: 3: 8.00 6.00 4.00 2.00 0.00 0 10 20 30 40 50 Time (min} Field-Saturated Hydraulic Conductivity -Infiltration Rate Case 1: L/h > 3 K sat= .__ __ o_. 0_2_1_6 _ __,! in/min 60 70 80 90 100 .__ __ 1_.3_0 __ __.! in/hr G·EC)CC)N Aardvark Permeameter Data Analysis Project Name: ___ M_il_e_s ..,.su.,,.b_d_i_v_is_io_n __ _ Project Number: G2037-32-01 9/28/2016 Date: By: TM ------------------- Bore ho I e Location: 1-4 Ref. EL (feet, MSL): -------- Bottom EL (feet, MSL): -------- 4.00 Borehole Diameter (inches) Borehole Depth, H (feet) Distance Between Reservoir & Top of Borehole (feet) 4.00 Wetted Area, A (in\._l ___ 8c....4_ . .c..5_2 __ _. Reading 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 C: 0 ·;; -ll. C: E ·-::it "'"' C: C: 0 :=-u OJ ....... OJ ra ~ a: $ Depth to Water Table, s (feet) Height APM Raised from Bottom (inches) 2.42 100 2.00 Distance Between Resevoir and APM, D (feet): Head Height, h (inches): Distance Between Constant Head and Water Table, L (inches): Time Time Elapsed Reservoir Water Resevoir Water Interval Water (min) (min) Weight {g) Weight (lbs) Consumption (lbs) 0.00 23.540 10.00 10.00 23.270 0.27 20.00 10.00 22.980 0.29 31.00 11.00 22.695 0.29 41.00 10.00 22.475 0.22 51.00 10.00 22.270 0.21 61.00 10.00 22.075 0.20 75.00 14.00 21.795 0.28 85.00 10.00 21.605 0.19 95.00 10.00 21.425 0.18 105.00 10.00 21.235 0.19 5.65 5.73 1158 Total Water Consumption {lbs) 0.27 0.56 0.84 1.07 1.27 1.47 1.75 1.94 2.12 2.31 Steady Flow Rate, Q (in3/min): 1.00 0.80 0.60 / .... 0.40 0.20 "v,.~--" 0.00 0 - 10 20 30 40 50 60 Time (min} Field-Saturated Hydraulic Conductivity -Infiltration Rate 70 80 90 100 *Water Consumption Rate (in3/min) 0.75 0.80 0.72 0.61 0.57 0.54 0.55 0.53 0.50 0.53 0.53 110 120 Case 1: L/h > 3 Ksat = .___o_._0_02_7 _ ___.! in/min ....._ __ o_.1_6 __ ___.I in/hr Soil Map—San Diego County Area, California (Miles Subdivision, Carlsbad) 468720 468900468840468870463780468810 % 4 468690 A 4687^468750 468780 Map Scale; l:l,420ifpfintedonAportrait(8.5"x 11") sheet 468810 468840 468870 iMeCen 468900 0 20 40 80 120 jFeet 0 50 100 200 300 Map projection: VVebMercator Comer coordinates: WGS84 Edge tics: UTMZlDne UN \W3S84 ySDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/27/2016 Page 1 of 3 Soil Map—San Diego County Area. California (Miles Subdivision. Carlsbad) MAP LEGEND Area of Interest (AOI) I I Area of Interest (AOI) Soils \ I Soil Map Unit Polygons Soil Map Unit Lines g Soil Map Unit Points Special Point Features §spoil Area 0 Stony Spot Ok Very Stony Spot Wet Spot A Other Special Line Features Blowout Water Features —- Streams and Canals Borrow Pit Transportation X Clay Spot ♦-Hf Rails 0 Closed Depression 0^^ Interstate Highways Gravel Pit 0^ US Routes «• •Gravelly Spot Major Roads o Landfill Local Roads A.Lava Flow Background Marsh or swamp ■■ Aerial Photography «Mine or Quarry o Miscellaneous V\^ter o Perennial Water V Rock Outcrop +Saline Spot • • • e Sandy Spot •»Severely Eroded Spot 0 Sinkhole >Slide or Slip 0 Sodic Spot MAP INFORMATION The soil surveys that comprise your AOI were mapped at 1:24,000. Warning; Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL; http;//websoilsurvey.nrcs.usda.gov Coordinate System; Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area; San Diego County Area, California Survey Area Data: Version 9, Sep 17, 2015 Soil map units are labeled (as space allows) for map scales 1 ;50,000 or larger. Date(s) aerial images were photographed; 2014 NOV3.2014—Nov22. The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 9/27/2016 Page 2 of 3 Soil Map-San Diego County Area, California Map Unit Legend Map Unit Symbol I CbC MIC MIE Totals for Area of Interest USDA Natural Resources "'iffl Conservation Service San Diego County Area, California (CA638) Map Unit Name Carlsbad gravelly loamy sand, 5 to 9 percent slopes Marina loamy coarse sand, 2 to 9 percent slopes Marina loamy coarse sand, 9 to 30 percent slopes I Acres in AOI Web Soil Survey National Cooperative Soil Survey I 1.9 1.0 1.4 4.3 Miles Subdivision, Carlsbad Percent of AOI 44.8% 23.5% 31.7% 100.0% 9/27/2016 Page 3 of 3 Map Unit Description: Carlsbad gravelly loamy sand, 5 to 9 percent slopes---San Diego County Area, California Miles Subdivision, Carlsbad San Diego County Area, California CbC-Carlsbad gravelly loamy sand, 5 to 9 percent slopes LSDA Natural Resources ~tfi Conservation Service Map Unit Setting National map unit symbol: hb99 Elevation: 30 to 300 feet Mean annual precipitation: 10 to 16 inches Frost-free period: 330 to 350 days Farmland classification: Farmland of statewide importance Map Unit Composition Carlsbad and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Carlsbad Setting Landform: Hillslopes Landform position (two-dimensional): Backslope Landform position (three-dimensional): Side slope Down-slope shape: Convex Across-slope shape: Convex Parent material: Ferruginous sandstone Typical profile H1 - 0 to 21 inches: gravelly loamy sand H2 -21 to 39 inches: loamy sand H3 -39 to 50 inches: indurated Properties and qualities Slope: 5 to 9 percent Depth to restrictive feature: 24 to 40 inches to duripan Natural drainage class: Moderately well drained Runoff class: Low Capacity of the most limiting layer to transmit water (Ksat): High (1.98 to 5.95 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Available water storage in profile: Very low (about 2.7 inches) Interpretive groups Land capability classification (irrigated): 3e Land capability classification (nonirrigated): 3e Hydrologic Soil Group: B Ecological site: SANDY (1975) (R019XD035CA) Hydric soil rating: No Web Soil Survey National Cooperative Soil Survey 9/27/2016 Page 1 of 2 Map Unit Description: Carlsbad gravelly loamy sand, 5 to 9 percent slopes---San Diego County Area, California Minor Components Chesterton Percent of map unit: 5 percent Hydric soil rating: No Marina Percent of map unit: 5 percent Hydric soil rating: No Unnamed, ponded Percent of map unit: 2 percent Landform: Depressions Hydric soil rating: Yes Redding Percent of map unit: 2 percent Hydric soil rating: No Unnamed Percent of map unit: 1 percent Landform: Sloughs Hydric soil rating: Yes Data Source Information Soil Survey Area: Survey Area Data: tSDA Natural Resources ~,rffl Conservation Service San Diego County Area, California Version 9, Sep 17, 2015 Web Soil Survey National Cooperative Soil Survey Miles Subdivision, Carlsbad 9/27/2016 Page 2 of 2 Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes---San Diego County Area, California Miles Subdivision, Carlsbad San Diego County Area, California MIC-Marina loamy coarse sand, 2 to 9 percent slopes Natural Resources Conservation Service Map Unit Setting National map unit symbol: hbdz Mean annual air temperature: 57 to 61 degrees F Farmland classification: Prime farmland if irrigated Map Unit Composition Marina and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Marina Setting Landform: Ridges Down-slope shape: Linear Across-slope shape: Linear Parent material: Eolian sands derived from mixed sources Typical profile H1 -0 to 10 inches: loamy coarse sand H2 -10 to 57 inches: loamy sand, loamy coarse sand H2 -10 to 57 inches: sand, coarse sand H3 -57 to 60 inches: H3 -57 to 60 inches: Properties and qualities Slope: 2 to 9 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Runoff class: Medium Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): 3s Land capability classification (nonirrigated): 4e Hydrologic Soil Group: B Hydric soil rating: No Web Soil Survey National Cooperative Soil Survey 9/27/2016 Page 1 of 2 Map Unit Description: Marina loamy coarse sand, 2 to 9 percent slopes---San Diego County Area, California Minor Components Carlsbad Percent of map unit: 5 percent Hydric soil rating: No Chesterton Percent of map unit: 5 percent Hydric soil rating: No Corralitos Percent of map unit: 5 percent Hydric soil rating: No Data Source Information Soil Survey Area: Survey Area Data: Natural Resources Conservation Service San Diego County Area, California Version 9, Sep 17, 2015 Web Soil Survey National Cooperative Soil Survey Miles Subdivision, Carlsbad 9/27/2016 Page 2 of 2 Map Unit Description: Marina loamy coarse sand, 9 to 30 percent slopes---San Diego County Area, California Miles Subdivision, Carlsbad San Diego County Area, California MIE-Marina loamy coarse sand, 9 to 30 percent slopes tSDA Natural Resources ~ tm Conservation Service Map Unit Setting National map unit symbol: hbfO Mean annual air temperature: 57 to 61 degrees F Farmland classification: Not prime farmland Map Unit Composition Marina and similar soils: 85 percent Minor components: 15 percent Estimates are based on observations, descriptions, and transects of the map unit. Description of Marina Setting Landform: Ridges Down-slope shape: Concave Across-slope shape: Linear Parent material: Eolian sands derived from mixed sources Typical profile H1 -0 to 10 inches: loamy coarse sand H2 -10 to 57 inches: loamy sand, loamy coarse sand H2 -10 to 57 inches: sand, coarse sand H3 -57 to 60 inches: H3 -57 to 60 inches: Properties and qualities Slope: 9 to 30 percent Depth to restrictive feature: More than 80 inches Natural drainage class: Somewhat excessively drained Runoff class: High Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) Depth to water table: More than 80 inches Frequency of flooding: None Frequency of ponding: None Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0 mmhos/cm) Available water storage in profile: Moderate (about 8.7 inches) Interpretive groups Land capability classification (irrigated): 4e Land capability classification (nonirrigated): 6e Hydrologic Soil Group: B Hydric soil rating: No Web Soil Survey National Cooperative Soil Survey 9/27/2016 Page 1 of 2 Map Unit Description: Marina loamy coarse sand, 9 to 30 percent slopes---San Diego County Area, California Minor Components Carlsbad Percent of map unit: 5 percent Hydric soil rating: No Chesterton Percent of map unit: 5 percent Hydric soil rating: No Corralitos Percent of map unit: 5 percent Hydric soil rating: No Data Source Information Soil Survey Area: Survey Area Data: LSDA Natural Resources ·m Conservation Service San Diego County Area, California Version 9, Sep 17, 2015 Web Soil Survey National Cooperative Soil Survey Miles Subdivision, Carlsbad 9/27/2016 Page 2 of 2 eOrder: 12177 from Associa Developer Services (Ken Mar) 1 of 2 Subject: eOrder: 12177 from Associa Developer Services (Ken Mar) From: ncb@ncbrepro.com Date: 5/26/2017 11:32 AM To: ncb@ncbrepro.com NCB Reprographics 2382 Camino Vida Roble Suite F Order 12177 Carlsbad, CA 92011 760-931-0504 phone 760-931-1867 fax . d;;>· www.ncbrepro.com Due Date: 05/26/2017 02:00 PM Project: Citrus Lane aka Orchard Heights Reference: Order Date: 05/26/2017 11:32 AM Project Number: 17.133 NCB BIZ HOURS: Monday -Friday, 8am -5pm Instructions: Path: '0Jllid!:o\Charon\ eorder\2017-05\26\12177 Associa Developer Services (Ken Marl Contact ASSOCIA DEVELOPER SERVICES (KEN Location: NCB MAR) Account: Debbie Briggs Comment: 5950 La Place Court Carlsbad, CA 92008 (760) 707-0567 debbie. briggs@associa.us J Billing '---. ~ .. ----~~------- ASSOCIA DEVELOPER SERVICES (KEN Method: On Account (Invoice/NET30) MAR) Account: Debbie Briggs Instructions: 5950 La Place Court Carlsbad, CA 92008 (760) 707-0567 deb bi e_._hdg_g~oc i a. us I Shipping ·-'"''"'"----··~~---ASSOCIA DEVELOPER SERVICES (KEN Method: Will-Call at NCB counter MAR) Account: Debbie Briggs Instructions: 5950 La Place Court Carlsbad, CA 92008 USA (760) 707-0567 debbie. briggs@associa.us iPlan~-·----·----·-------·---·--------- Full Size Sets: 1 Half Size Sets: 0 Binding: Loose Printing: Black & White Instructions: Pleasee print full-size to scale. Media: Bond: White Media Size: null Media Color: CD/DVD/USB: Archive: No Burn CD: No Folding: None Laminating: # Name Media Type Output 5/26/201711:47 AM eOrder: 12177 from Associa Developer Services (Ken Mar) 1 Citrus Lane 95 aka Orchard Heights Plan.pdf Bond: White Plans Thank you for your order! We appreciate your business. 2 of 2 5/26/201711:47 AM