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HomeMy WebLinkAboutCT 10-01; Sea Breeze Villas; Storm Water Management Plan; 2011-06-30i .initial 12]^ Date STORM WATER MANAGEMENT PLAN (SWMP) Project Site: FOR SEA BREEZE VILLAS Project No. CT-10-01 391 Tamarack Avenue Carlsbad, California Prepared For: Date Prepared: DS PRODUCTS, INC. A California Corporation 32 Sylvan Irvine, California 92603 June 30,2011 < Prepared By: DMS CONSI)ANT-S, JNC. CIVIL ENGINEERS 12371 Lewis Street, Suite 203 Garden Grove, CA 92840 714.740.8840 CD DC > Sea Breeze Villas - Storm Water Management Plan ^ City of Carlsbad I^ECORD COPY 1 SWMP 11-02 STORM WATER MANAGEMENT PLAN (SWMP) For SEA BREEZE VILLAS PROJECT NO. CT 10-01 Prepared By: DMS CONSULTANTS, INC. SURENDER DEWAN, P.E. 12371 LEWIS STREET, SUITE 203 GARDEN GROVE, CA 92840 714.740.8840 Surender@DMSConsultantslnc.com Prepared For: DS PRODUCTS INC., A CALIFORNIA CORPORATION 32 SYLVAN IRVINE, CA 92603 L , June 30, 2011 June 30, 2011 PaS^I Sea Breeze Villas - Storm Water Management Plan CERTIFICATION This Storm Water Management Plan (SWMP) has been prepared under the direction of the following Registered Civil Engineer. The Registered Civil Engineer (Engineer) attests to the technical information contained herein and the engineering data upon which the following design, recommendations, conclusions and decisions are based. The selection, sizing, and preliminary design of stormwater treatment and other control measures in this report meet the requirements of Regional Water Quality Control Board Order R9- 2007-0001 and subsequent amendments. Surender Dewan, P.E. REGISTERED CIVIL ENGINEER g/z3ll/ Date OWNER'S CERTIFICATION This Storm Water Management Plan (SWMP) has been prepared for TMS Development, LLC by DMS Consultants, Inc. The SWMP is intended to comply with the requirements of the City of Carlsbad, Urban Runoff Management Program and Stormwater Ordinance, as well as the Municipal Stormwater Permit which requires the preparation of SWMPs for priority development projects. The undersigned, while it owns the subject property, is responsible for the implementation of the provisions of this SWMP. The undersigned will ensure that this plan is amended as appropriate to reflect up-to-date conditions on the site consistent with the current City of Carlsbad Runoff Management Program and the intent of the NPDES/MS4 Permit for Waste Discharge Requirements as authorized by the State and EPA. Once the undersigned transfers its interest in the property, its successors-in-interest shall bear the aforementioned responsibility to implement and amend the SWMP. An appropriate number of approved and signed copies of this document shall be available on the subject site in perpetuity. I certify that, as owner of the property described herein, I have read and understand the requirements of this Storm Water Management Plan (SWMP) and that I am responsible for ensuring that all storm water treatment measures described within said SWMP will be properly implemented, monitored and maintained. Signed: Name: Company/Owner: Address: DS Products Inc., A California Corporation 32 Sylvan Irvine, California 92603 Title: Telephone #: Date: June 30, 2011 Page 2 Sea Breeze Villas - Storm Water Management Plan TABLE OF CONTENTS CERTIFICATION 1.0 INTRODUCTION 5 2.0 APPLICABILITY AND PROJECT TYPE 6 3.0 PROJECT OVERVIEW 7 3.1 Project Location ^ 3.2 Project Description ^ 3.3 Project Size ^ 3.4 Impervious and Pervious Surface areas 7 4.0 PROJECT SITE ASSESSMENT 8 4.1 Land Use and Zoning 8 4.2 Existing Topography 8 4.3 Existing and Proposed Drainage 8 4.4 Watershed and Receiving Waters 8 4.5 303(d) Listed Receiving Waters 8 4.6 Total Maximum Daily Loads (TMDLs) 9 4.7 Soil Type(s) and Conditions 9 5.0 POLLUTANTS OF CONCERN 10 5.1 Project Categories and Features 10 5.2 Project Watershed Information 10 5.3 Hydromodification 110 6.0 HYDROLOGIC & GEOTECHNICAL CONDITIONS OF CONCERN/ DRAINAGE REPORT 12 7.0 BEST MANAGEMENT PRACTICES (BMPs) 13 7.1 LID Site Design Strategies and BMPs 13 7.1.1 Optimize the Site Layout 13 7.1.2 Use Pervious Surfaces 14 7.1.3 Disperse Runoff 1^ 7.1.4 Integrated Management Practices (IMPs) 14 7.2 Source Control BMPs 14 7.3 Treatment Control BMPs 16 7.3.1 Selection 16 7.3.2 Design and Sizing 1^ June 30, 2011 Page 3 Sea Breeze Villas - Storm Water Management Plan 8.0 PROJECT PLAN(s) & BMP LOCATION MAP 18 9.0 BMP MAINTENANCE 19 9.1 Facility Ownership & Maintenance Agreements 19 9.2 Operations, Maintenance and Inspection 19 9.2.1 Typical Maintenance Requirements 19 9.2.2 Operation and Maintenance (O&M) Plan 19 9.2.3 Project BMP Verification 19 9.24 Annual BMP Operation and Maintenance Verification 20 ATTACHMENTS Attachment A Water Quality Treatnfient Plan Attachment B Grading Plan Attachment C Soils Report Attachment D Hydrology Study (Pre and Post Construction Conditions) Attachment E UNI ECO-STONE Permeable Pavers • Baffle Box, Suntree Technologies, Inc. Attachment F Biology Study at Discharge Point of Agua Hedionda Lagoon June 30, 2011 Page 4 Sea Breeze Villas - Storm Water Management Plan 1.0 INTRODUCTION This Storm Water Management Plan (SWMP) is required by the City of Carlsbad for all Development and Redevelopment Projects, pursuant to the City of Carlsbad Stormwater Management and Discharge Control Ordinance (Municipal Code Section 15.12). The purpose of this SWMP is to address the water quality impacts from the proposed Sea Breeze Villas. The site design, source control and treatment control Best Management Practices (BMPs) will be utilized to provide long term solution to protecting water quality. This SWMP is subject to revisions as needed to accommodate changes to the project design, or as required by the City and/or Engineer. June 30, 2011 P^geS Sea Breeze Villas - Storm Water Management Plan 2.0 APPLICABILITY AND PROJECT TYPE Based on the criteria established in Order R9-2007-0001 NPDES No. CAS0108758 Section D.I, and review of the City's Standard Urban Stormwater Management Plan Section G (local SUSMP) Chapters 1 and 3, and after completion of the City of Carlsbad's Checklist for New Development and Redevelopment Projects, the proposed project is identified as a Priority Development Project. Since the proposed project has been identified as a Priority Project, this SWMP includes design and supporting calculations for site design Low Impact Development (LID) BMPs, Source Control BMPs, and Treatment Control BMPs. June 30, 2011 PaQeS Sea Breeze Villas - Storm Water Management Plan 3.0 PROJECT OVERVIEW 3.1 Project Location The project site is located in the City of Carisbad on the south side of Tamarack Avenue, adjacent and west of the railroad right-of-way, at 391 Tamarack Avenue, APN 206-020-08. Figure 3.1 illustrates the project location. The Tentative Map includes the project details, as further discussed in this section. Figure 3.1 3.2 Project Description The proposed Sea Breeze Villas project is a private 12-unit airspace condominium project with a play area located north of Building B. The project has a total of 5 guest parking spaces. To conform to LID requirements for BMPs, the project utilizes the use of permeable pavers manufactured by ECO Stone. These pavers are located in the center 8-foot wide section of the driveway. Overflow from the site drains via a 12-inch diameter PVC drain which connects to an existing catch basin located along the southeriy curb of Tamarack Avenue. The yard drains in the project area tie to the underground storm drain system. This system extends to a box culvert drain in the railroad right-of-way which ultimately discharges at Agua Hedionda Lagoon. The existing site has a single family home on it. The home is to be demolished. The property is surrounded to the west and south by multifamily development and by the railroad to the east. The detailed single sheet post-construction BMP exhibit is included as Attachmer)t A. 3.3 Project Size The project is located on a 0.70 acre site. The total disturbed area of the site is 0.70 acres. The project will be built in one phase. 3.4 Impervious and Pen/ious Surface areas The existing site is approximately 90% pervious. The proposed development after completion will be about 75% impervious. The project will result in an increase in impervious area from existing to final development conditions. June 30, 2011 Page? Sea Breeze Viiias - Storm Water Management Plan 4.0 PROJECT SITE ASSESSMENT This section includes information used to consider the potential water quality and hydrologic impacts from the proposed project. This information is important when considering the appropriate BMPs to reduce identified potential impacts as well as when designing low impact development (LID), source control and treatment control measures to reduce those impacts. Constraints presented by high density land use eliminated the use of urban green biofilter, vegetated swales, wetlands/wetponds. Use of UNI Eco-Stone permeable pavers provided the opportunity to infiltrate the runoff into the ground. 4.1 Land Use and Zoning The existing land use on the project is RD-M. 4.2 Existing Topography The existing site is fairiy flat and draws from north to south. The site has no definite drainage pattern. 4.3 Existing and Proposed Drainage The existing site drains southeriy in an uneven fashion towards the railroad property. The proposed drainage system consists of permeable pavers manufactured by UNI Eco-Stone. These pavers are installed in the center of the driveway. The pavers are laid over a bedding course of V/2 to 2" thick aggregate which is laid over a stone open graded base. Overflow/secondary outlet from the site consists of a 12" diameter PVC storm drain which connects to a public storm drain on Tamarck Avenue that connects to storm drain discharging at Agua Hedionda Lagoon. 4.4 Watershed and Receiving Waters The proposed project is located within the Carisbad (HU 904) watershed or hydrologic unit and the subwatershed or hydrologic area of Encinas. The surface and groundwater receiving waters located in the area and downstream of this project include Agua Hedionda Lagoon. The designated beneficial uses of these waters include MUN, AGR, RECl. REC2, IND, PROC, GWR, FRSH, NAV, POW and COMM. 4.5 303(d) Listed Receiving Waters The receiving water body for the project is Agua Hedionda Lagoon and the ultimate receiving body is Pacific Ocean. The receiving water is impaired for the following pollutants. Agua Hedionda Lagoon: indicator bacteria, sedimentation/siltation; Pacific Ocean Shoreline (Buena Vista Creek HA, Escondido Creek HA, Loma Alta HA, San Marcos HA): indicator bacteria. June 30,2011 Page 8 Sea Breeze Villas - Storm Water Management Plan 4.6 Total Maximum Daily Loads (TMDLs) Hydrologic Descriptor Water Quality Limited Segment Nutrients/ Eutrophication Sedimentation/ Siltation TDS Bacteria Lower YsidoraHSA (902.11) Santa Margarita Lagoon Yes Loma Alta HA (904.10) Loma Alta Slough Yes Yes Loma Alta HA (904,10) Pacific Ocean Shoreline at Creek Yes El Salto HSA (904,21) Buena Vista Lagoon Yes Yes Yes Buena Vista Creek HA (904,20) Pacific Ocean Shoreline at Creek Yes * LosMonosHSA (904,31) Agua Hedionda Lagoon Yes Yes Los Monos HSA (904,31) Lower Agua Hedionda Creek Yes San Elljo HSA (904,61) San Elijo Lagoon Yes Yes Yes Escondido Creek HA (904,60) Pacific Ocean Shoreline at Lagoon Yes Miramar Reservoir HA Los Penasquitos Lagoon Yes Mission San Diego HSA (907,11) Famosa Slough & Channel Yes 4.7 Soil Type(s) and Conditions A soils report prepared by Strata-Tech, Inc. dated April 20, 2010 indicates that the existing soil is mostly light brown medium to fine grade sand, under laid with 2' to 3' of natural soil brown silty sand. There was no ground water encountered up to a depth of 10 feet. June 30, 2011 Page 9 Sea Breeze Villas - Storm Water Management Plan 5.0 POLLUTANTS OF CONCERN Per Table 2-1 of City SUSMP, the potential storm water or urban runoff pollutants expected to be associated with this project, an attached residential development and parking lot are: • Bacteria and Viruses: Anticipated sources include animal excrement (found in areas where pets are often walked), sanitary sewer overflow and trash container handling areas. • Oil and Grease: Potential sources of oil and grease include motor vehicles. • Oxygen-Demanding Substances: Potential sources include biodegradable organic materials and various household chemicals, which deplete dissolved oxygen levels in water courses. Anticipated storm water or urban runoff pollutants expected to be associated with the project are: Sediment: Landscape areas and roof-tops are expected to be common sources of sediment due to erosion and wear. Nutrients: Nutrients, including nitrogen, phosphorus and other compounds can be anticipated to be generated by organic litter, fertilizers, food waste, sewage and sediment. Metals: Potential sources of trace metals (copper, lead, cadmium, chromium, nickel and zinc) include motor vehicles, re-roofing and hardscape/construction materials, and chemicals. Pesticides: Sources of pesticides include household bug spray, weed killers and other household sources. Trash and Debris: These sources include common litter, biodegradable organic matter such as leaves, grass cuttings and food wastes from landscaped areas and homeowners. 5.1 Project Categories and Features The project is an attached residential development. 5.2 Project Watershed Information The Carisbad Hydrologic Unit (HU) 4.00 is approximately 210 square miles extending from the headwaters above Lake Wolhford in the east to the Pacific Ocean in the west, and from Vista and Oceanside in the north to Solana Beach, Escondido, and the community of Rancho Santa Fe to the south. The cities of Carisbad, San Marcos, and Encinitas are entirely within this HU. There are numerous important surface hydrologic features within the Carisbad HU including 4 unique coastal lagoons, 3 major creeks, and 2 large water storage reservoirs. The HU contains four major coastal lagoons. From north to south they are Buena Vista (901.2), Agua Hedionda (904.3), Batiquitos (904.5), and San Elijo (904.6) HAs. There are other HAs and HSAs in the project area as listed below. BASIN NUMBER HYDROLOGIC BASIN BASIN NUMBER HYDROLOGIC BASIN 4,00 CARLSBAD HYDROLOGIC UNIT 4,10 Loma Alta HA 4,50 San Marcos HA 4,20 Buena Vista Creek HA 4,51 Batiquitos HSA 4,21 BSalto HSA 4,52 Richland HSA 4,22 Vista HSA 4,53 Twin Oaks HSA 4,30 Agua Hedionda HA 4,60 Escondido Creek HA 4,31 Los Monos HSA 4,61 San Elljo HSA 4,32 Buena HSA 4,62 Escondido HSA 4,40 Encinas HA 4,63 LakeWohlford HSA June 30, 2011 Page 10 Sea Breeze Villas ~ Storm Water Management Plan 5.3 Hydromodification In accordance with City's standards, it was determined (see Attached HMP Applicability Determination Sketch, Figure 2-1 of City's SUSMP) that the project is exempt from hydromodification, per node 7 and 8 of Figure 2-1 which states "for projects discharging runoff directly to a hardened conveyance or rehabilitated stream system that extends to exempt receiving waters". The project discharges via a City maintained system into Agua Hedionda Lagoon, via an 84-inch diameter storm drain. Plans obtained from the City of Carisbad for the 84-inch diameter storm drain (Dwg No. 360-5, Project No. 3182/3528) indicate that the existing Qioo at outlet is 453 cfs. An additional 0.30 cfs (increased runoff) from the site will have a very minimal or no impact to the capacity of this system. However, since the project is discharging to a tidely influenced lagoon, the enclosed Biology Study is included as required per the exemption under node 6. The study concludes: The water outflow from the existing drain system has a minor depressive effect on the salinity levels within the Central Basin of Agua Hedionda during peak events associated with the 100-year storm. Such effects are a normal condition within coastal lagoons, and the vegetation and wildlife that are associated with estuarine conditions are well adapted to such salinity fluctuations. The proposed projects output would be insignificantly small compared to the existing conditions, causing a change in salinity of only about 0.02 ppt. In addition, the analysis did not consider the much greater effects on lagoon salinity associated with the inflow of Agua Hedionda Creek to the Inner Basin, which has a design flow 010 of more that 2,100 cfs(or 4.6 times greater than the QIOO from the 84" storm drain). Because of the lack of vegetation from the storm drain outfall to the unvegetated tidal flats of the lagoon, the project would have no effect on existing vegetation. Since the site would be covered by the condominium project and storm flows routed through BMPs, flows originating from the site would not transport or erode material that could then be transported to the lagoon and so effect the current impairment issue regarding sedimentation/siltation. Further the Bio Clean Device will serve to effectively reduce sediment from the site and reduce the bacteria typically found in organic wastes contained in urban discharges. Based on the results of this analysis, the proposed project would have no measurable detrimental effect on the water quality being discharged to Agua Hedionda, nor would it alter salinity or otherwise change the quality of the various habitats associated with the receiving water body. June 30,2011 Page 11 SECTION 2 I DENTIFY POLLUTANTS, BMP SIZING AND SELECTION R«-d*sign Bwgy Dissipalion System HMPBccmfK End of Decision Matrix t4. HydrambdMcaim Conmts RcqiAed 0»i» Figure 23 of Dwistoliialrtt FIGURE 2-1. HMP Applicability Determination* *refer to expanded HMP exemption criteria below for justifications required on each node 30 City 6f Carlsbad SUSMP - January 14, 2011 Sea Breeze Villas - Storm Water Management Plan 6.0 HYDROLOGIC & GEOTECHNICAL CONDITIONS OF CONCERN/ DRAINAGE REPORT This section of the SWMP identifies hydrologic and geotechnical conditions of concern related to the proposed project. Impacts to the hydrologic regime resulting from development typically include increased runoff volume and velocity; reduced infiltration; increased flow frequency, duration, and peaks; faster time to reach peak flow; and water quality degradation. A change to a priority project site's hydrologic regime is considered a condition of concern if the change impacts downstream channels and habitat integrity. Conditions of concern can include problems such as flooding, erosion, scour, and other impacts that can adversely and permanently affect channel and habitat integrity. There are no hydrological and geotechnical conditions of concern. A drainage report was prepared for the proposed project by DMS Consultants, Inc., as required by the City, and is included as an Attachment D. A geotechnical report was also prepared for the proposed project by Strata-Tech, Inc., dated April 20, 2010, as required by the City, and is included as Attactiment C. June 30,2011 PaQe^2 Sea Breeze Villas - Storm Water Management Plan 7.0 BEST MANAGEMENT PRACTICES (BMPs) Minimizing the proposed project's effects on water quality, as well as compliance with State and local requirements can be most effectively achieved by using a combination of BMPs which include Low Impact Design (LID) Site Design, Source Control, and for Priority projects, Treatment Control measures. These design and control measures employ a multi-level strategy. The strategy, which is detailed in the City's Stormwater Standards Manual Section 1 of SUSMP, consists of: 1) reducing or eliminating post-project runoff; 2) controlling sources of pollutants; and 3) treating stormwater runoff before discharging it to the storm drain system or to receiving waters. This SWMP and the proposed BMPs for the proposed project have been developed to minimize drainage impacts identified in Section 5 of this report and the introduction of pollutants identified in Section 2 of City's Stormwater Standards Manual, into the municipal storm drain system and/or ultimate drainage receiving waterbody. 7.1 LID Site Design Strategies and BMPs Conceptually, there are four LID strategies for managing runoff from buildings and paving: 1. Optimize the site layout; 2. Use pervious surfaces; 3. Disperse runoff; and 4. Design Integrated Management Practices (IMPs). Where the project is located within the Agua Hedionda Hydrologic Area, the following design strategies shall be implemented where applicable and feasible. • Medium Density Residential: A cluster design will be used, grouping the housing units closer together on smaller lots, and leaving one-third of the site as undeveloped open space. Impervious area shall be reduced by decreasing driveway length, sidewalk use, and overall road footprint. • Multifamily Residential: Impervious area will be reduced somewhat by more efficient layout. Impervious area has been substantially reduced by use of permeable pavers in the driveway. 7.1.1 Optimize the Site Layout The development has incorporated by design, reduced street widths to reduce the amount of impervious area. The project also includes multi-level units to reduce the amount of runoff and reduce overall footprint. As part of the design of all common area landscape areas, similar planting material with similar water requirements will be used to reduce excess irrigation runoff and promote surface filtration. June 30,2011 Page 13 Sea Breeze Villas - Storm Water Management Plan 7.1.2 Use Pervious Surfaces Pervious pavers will be used in the drive area to retain runoff. An emergency inlet has been provided at the downstream end of the driveway for emergency overflow. The runoff from this overflow will drain via a 12-inch PVC storm drain and connect to an existing catch basin located in Tamarack Avenue. The runoff from rear yards will be directed to a baffle box located downstream of rear yards before out- letting into the storm drain system. 7.1.3 Disperse Runoff The runoff from impervious areas drain to impervious pavers located in the center of the driveway. Runoff from patios drain to flow through planters. 7.1.4 Integrated Management Practices (IMPs) IMP used for the project is a permeable interiocking concrete pavers manufactured by UNI Eco-Stone, over 8-inch of open graded gravel as an infiltration trench. 7.2 Source Control BMPs It is anticipated that the following pollutants will be generated at this site: Sediment: Landscape areas and roof-tops are expected to be common sources of sediment due to erosion and wear. Nutrients: Nutrients, including nitrogen, phosphorus and other compounds can be anticipated to be generated by or founding organic litter, fertilizers, food waste, sewage and sediment. Metals: Potential sources of trace metals (copper, lead, cadmium, chromium, nickel and zinc) include motor vehicles, re-roofing and hardscape/construction materials, and chemicals. Pesticides: Sources of pesticides include household bug spray, weed killers and other household sources. Trash and Debris: These sources include common litter, biodegradable organic matter such as leaves, grass cuttings and food wastes from landscaped areas and homeowners. Based on these anticipated pollutants and operational activities at the site the following Table 7-1 summarizes the Source Control BMPs to be installed and/or implemented onsite. June 30, 2011 PageU Sea Breeze Villas - Storm Water Management Plan TABLE 7-1 Stormwater Pollutant Sources/Source Control Checklist How to use this worksheet, 1, Review Column 1 and identify which of these potential sources of stormwater pollutants apply to your site. Check the box that applies, 2, Review Column 2 and incorporate all of the corresponding applicable BMPs in your project-specific SUSMP drawings, 3, Review Columns 3 and 4 and incorporate all of the corresponding applicable permanent controls and operational BIWPs in a table in your Project-Specific SUSMP, Use the format shown in Appendix 1 of SUSMP, Describe your specific BMPs in an accompanying narrative and explain any special conditions or situations that required omitting BMPs or substituting alternatives. IF THESE SOURCES WILL BE ON THE PROJECT SITE... 1 Potential Sources of Runoff Pollutants A, On-site storm drain inlets D2, Landscape/ outdoor pesticide use ...THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCE CONTROL BMPs Permanent Controls-show on SUSMP drawings ^ Location of inlets. Permanent Controls-List in SUSMP Table and Narrative Mark all inlets with the words "No Dumping! Drains to Creek" or similar. Manage landscape and irrigation procedures and management of use of fertilizers and pesticides. Operational BMPs-lnclude in SUSMP Table and Narrative IAI Maintain and periodically repaint or replace inlet markings ^ Provide stormwater pollution prevention information to new site owners, lessees, or operators, ^ See applicable operational BMPs in Fact Sheet SC-44,"Drainage System Maintenance," in CASQA Stormwater Quality Handbooks at www,cabmDhandbooks,com 13 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 potential discharge to storm drains," Monthly during regular maintenance. June 30, 2011 Page 15 Sea Breeze Villas - Storm Water Management Plan 7.3 Treatment Control BMPs Given below is the basis of selection of use of permeable pavers as BMP and the related calculations. 7.3.1 Selection Various BMPs including modular wetland system, urban green biofiller, flow through planter box, vegetated swale and wetlands/wetponds were considered for the facility but not found feasible because ofthe following reasons. 1. The natural terrain is not existent for wetlands and reuse. Also the existing ground is not habitable for it. 2. Vegetated swale was not considered suitable for the site due to the high density land use and development leaving unsuitable amount of area for such BMPs. 3. Bioretention facilities, settling basins and higher-rate biofilters were not considered suitable for the site due to the high density land use and development leaving unsuitable amount of area for such BMPs. Table 7-2 provides a general comparison of how various types of treatment facilities perform for each group of pollutants. The pollutants for the proposed project are identified in Section 5. TABLE 7-2 Groups of Pollutants and Relative Effectiveness of Treatment Facilities. Bioretention Facilities (LID) Settling Basins (Dry Ponds) Wet Ponds and Constructed Wetlands Infiltration Facilities or Practices (LID) Media Filters Higher-rate biofilters Higher- rate media filters Trash Racks & Hydro -dynamic Devices Vegetated Swales Pollutant of Concern: Coarse sediment and trash High High High High High High High High High Pollutant of Concern: Pollutants that tend to associate with fine particles during treatment High High High High High Medium Medium Low Medium Pollutant of Concern: Pollutants that tend to be dissolved following treatment Medium Low Medium High Low Low Low Low Low Based on this, the following facility has been selected for the proposed project: • UNI Eco-Stone pavers were selected for the project because not only does it conform to LID requirements; it also allows reduction of volume and peak flows, improved water permeable pavers, filtering of pollutants and recharge of ground water. The Geotechnical report included as Attachment C of this report indicates that the ground water is 10 feet or greater from infiltration facility. Rear yards will be treated by installing a baffle box, model NSBB-2-4-60, manufactured by Suntree Technologies, Inc., downstream of rear yards before outletting to 18-inch diameter on-site storm drain system, see Attachment A, B and E. June 30, 2011 Page 16 Sea Breeze Viiias - Storm Water Management Plan 7.3.2 Design and Sizing The selected BMP will provide adequate treatment. Storm Quality Volume Based (SQVB) method was used for sizing the BMP. Table 7-3 provides the storm water quality calculations for the selected BMP. TABLE 7-3 Storm Water Quality Calculations. Storm Water Quality Calculations for Sea Breeze Villas Site Data Value Units Graded Area 30100 sf 85th Percentile Depth 0.61 in Soil Group B Pre Project Runoff Coefficient "C" 0.25 Post Project Runoff Coefficient "C" 0.58 Stomi Water Quality Volume Pre Project 85th Percentile Runoff Volume 382.52 ft'^3 Post Project 85th Percentile Treatment Runoff Volume 887.45 r3 Required Infiltration Volume (LID) 504.9275 ft'^3 Required Infiltration Volume (LID) (see following Design for Infiltration of Treatment Volume 887.45 ft*3 attachment) Available Storage Paver Length 285 ft Paver Width 8 ft Paver Area 2280 ft'^2 Gravel Sub-base Depth 12 in Porosity 0.4 >887 >887 Total Storage Volume Available 912 ft*3 OK Time for Comolete Infiltration Infiltration Area 2280 ft'^2 Infiltration Rate 15 gal/day/square foot Infiltration Rate 2.003 cubic feet /day / square foot Total Infiltration Per Day 4566.09 cubic feet/ day Total Infiltration Per Hour 190.25 cubic feet/hour Required Infiltration Time 4.66 hours < 72 Hours OK June 30, 2011 Page 17 100 Year Hvdrojogv Calculations for Seabreeze Villas Site Data Value Units Graded Area 30100 sf Soil Group B Pre Project Runoff Coefficient "C" 0.25 Post Project Project Runoff Coefficient "C" 0.58 Pre Proiect 100 vear 6hr Runoff Pre Project Ti 10.90 nnin Earth Swale Length 210.00 ft Earth Slope 0.020 percent Earth Swale Z 20.00 Earth Swale N 0.025 ft Earth Swale Flow Depth 0.210 ft Earth Swale Velocity 0.56 ft/sec Earth Swale Tt 6.24 min Tc = Ti 4- Tt 17.14 min 100 year 6 hr Depth 2.50 in 100 year 6 hr intensity 2.98 in/hr 100 Year flow rate 0.51 cfs Post Proiect 100 vear 6hr Runoff Post Project Ti 8.20 min Paver Swale Length 235.00 ft Paver Slope 0.005 percent Paver Swale Z 50.00 Paver Swale N 0.02 Paver Swale Flow Depth 0.155 ft Paver Swale Velocity 0.75 ft/sec Paver Swale Tt 5.24 min Pipe Size 12.00 in Pipe Length 275.00 ft Pipe Velocity (Assunne pipe flows full) 1.04 ft/sec. Pipe Tt 4.39 min Total Tt 9.63 min Tc 17.83 min 100 year 6 hr Depth 2.50 in Infiltration Depth (See Storm Water Calculations) 0.61 in <— Effective 100 6hr Depth at ground surface 1.89 in 100 year 6 hr intensity 2.19 in/hr Infiltration Area 2280.00 ff^l Graded Area Less Infiltration Area 27820.00 ft'^2 100 Year flow rate 0.81 cfs Post project 85* percentile treatment runoff volume = 30,100.00x061x0.58 = 887.45 12 PCSWMM for Permeable UNI ECO-STONE® Pavements File: untitled.PCS Date: 1/31/2003 4:14:50 PM 1.0 Input Parameters Paver Description: Clogging Potential Void condition Infiltration rate Area Slope Length of overland flow Run-on Description: Type of surface Area Slope Length of overland flow Manning's n Depression storage Base Description: Base material Depth of base Porosity Saturated H.K, Field capacity Curve fitting parameter Tension / soil moisture Initial moisture content Initial depth of water Drainage Description: Drainage type Threshold elevation Flow coefficient Flow exponent Subgrade Description: Subgrade soil type Percolation coefificient Design storm: Rainfall time step Rainfall values (in/hr) Medium New Installation 7.8 in/hr 1400 fp 0.5 % 280 ft No run-on Oft^ 0.5 % Oft 0.014 0.02 in Open graded Bin 0.38 3500 in/hr 0.05 10 15 ft/fraction 5% 0 in Slow drainage 0 in 1 in/hr-ff^exp 2 Silty Clay to Sandy Clay (SC,CL) 0.2 in/hr 5 minutes 0.2, 0.2, 0.2, 0.67, 1.08, 2.66, 1.44, 0.67, 0.67, 0.2, 0.2, 0.2 Evaluation Criteria: Allowable surface runoff 5% (4.0784725 ft') Allowable base water depth 85 % (6.8 in) 2.0 Computational Results Maximum depth of groundwater In base material: 1.992 in Volume Depth 81.56945 ff" 0.699 in 81.08334 fp 0.695 in .4861096fp 0.004 in Ofl!' 0.000 in Off 0.000 in Volume Depth 4.21355 fl:' 0.036 in 8.424065 fP 0.072 in 46.66667 fP 0.400 in 114.7251 fP 0.983 in Overall runoff coefficient (C=R/P): 0 Surface summary: Total rainfall Total infiltration Total evaporation Total runoff Remaining surface storage Subsurface summary: Total lateral base drainage Total deep percolation Initial storage in base Final storage in base Continuity errors in computation: Surface continuity 0.000 percent Channel continuity -4.885 percent Groundwater continuity -0.042 percent Notice: The PCSWMM for Penneable Pavements software package is only a tool to aid design and for general guidance. The results given above are not a substitute for engineering skill and judgement and in no way replace the services of experienced and professionally qualified civil engineering consultants. Further, PCSWMM for Penneable Pavements is an interface for the USEPA Stormwater Management Model (SWMM) program - the results above are produced by the SWMM program and no guarantee is made by Computational Hydraulics int. or F. VON LANGSDORF LICENSING LTD. as to the validity of these results. Full responsibility for the use of these results and this software package for any project remains wholly with the user. UNI® and ECO-STONE® are trademarks of F. VON LANGSDORF LICENSING LTD. PCSWMM™ is a trademark of Computational Hydraulics Int. PC JWMM 2005 for Permeable I H\ ECO-STONE PavementI ) untitled 1/31/2003 4:14:50 PM 750u 500u 250u 0 1 0 Q. 'o OJ CL 6 4 0.0 Time since start of simulation (hours) 8 Sea Breeze Villas - Storm Water Management Plan 8.0 PROJECT PLAN(s) & BMP LOCATION MAP A BMP map included as Attachment A, illustrates the BMPs that will be implemented as described in Section 7 of this Storm Water Management Plan. June 30, 2011 Page 18 Sea Breeze Villas - Storm Water Management Plan 9.0 BMP MAINTENANCE 9.1 Facility Ownership & Maintenance Agreements The following individual(s)/organization will own the facilities, including all structural and non-structural BMPs, and are responsible for maintenance in perpetuity: DS Products, Inc. Contact Person: Tony Sfreddo 32 Sylvan 951.801.0888 Irvine, CA 92603 9.2 Operations, Maintenance and Inspection 9.2.1 Typical Maintenance Requirements All permeable pavements, including porous asphalt and pervious concrete, require periodic cleaning to maintain high infiltration rates, and care must be taken to keep sediment off the pavement during and after construction. Studies and field experience have shown that infiltration rates may be maintained by street sweeping/vacuuming. The frequency of cleaning is typically dependent on traffic levels. It is generally recommended to vacuum the pavement surface at least once or twice a year. Periodic inspections ofthe site should be conducted for ponding or areas with reduced levels of infiltration. The frequency of service should be 1 - 4 times per year determined by the accumulation of sediment and debris in the Nutrient Separating Baffle Box. The service will include cleaning the screen system, removing collected sediment from the baffle chambers and inspecting the Storm Boom for replacement in the skimmer system. The primary method used to service the Nutrient Separating Baffle Box is by vacuuming with a Vactor type unit. 9.2.2 Operation and Maintenance (O&M) Plan An O&M Plan is provided with this Storm Water Management Plan in Section 9.0. An O&M Plan has been prepared for the proposed project and submitted for approval by the City prior to entitlements. The O&M Plan describes the designated responsible party to manage the stormwater BMP(s), employee's training program and duties, operating schedule, maintenance frequency, routine service schedule, specific maintenance activities, copies of resource agency permits, and any other necessary activities. At a minimum, maintenance agreements shall require the inspection and servicing of all structural BMPs per manufacturer or engineering specifications. Parties responsible for the O&M Plan shall retain records for at least 5 years. These documents shall be made available to the City for inspection upon request at any time. 9.2.3 Project BMP Verification The applicant's Engineer of Record must verify through inspection of the site that the BMPs have been constructed and implemented as proposed in the approved SWMP. The inspection must be conducted and City approval must be obtained prior to granting a certificate of occupancy. This approval may be verified through signatures on the as-built plans, specifically on the BMP sheet. June 30,2011 Page 19 Sea Breeze Villas - Storm Water IVIanagement Plan 9.2.4 Annual BMP Operation and Maintenance Verification The BMP owner must verify annually that the O&M Plan is being implemented by submitting a self- certification statement to the City. The verification must include a record of inspection of the BMPs prior to the rainy season (October of each year). "I certify that, as owner of the property described herein, I have read and understand the requirements of this Storm Water Management Plan (SWMP) and that I am responsible for ensuring that all storm water treatment measures described within said SWMP will be properly implemented, monitored and maintained." DS Products, IncLA California Corporation Date June 30, 2011 Page 20 Operations and Maintenance Plan Page 1 of 7 Sea Breeze Viiias - Carlsbad, CA BMP Applicable? Yes/No BMP Name and BMP Implementation, Maintenance, and Inspection Procedures Implementation, Maintenance, and Inspection Frequency and Schedule Person or Entity with Operation & Maintenance Responsibility Non-Structural Source Control BMPs Yes N1. Education for Property Owners, Tenants and Occupants HOA will insure that all homeowners will be given a copy of the recorded CC&Rs, which will contain a section outlining the environmental awareness education materials. The HOA will establish requirements for the implementation of a community awareness program that informs home buyers of the impacts of dumping oil, paints, solvents or other harmful chemicals into the stomn drain; the proper use and management of fertilizers, pesticides and herbicides in home landscaping and gardening practices; the impacts of littering and improper watering. Environmental awareness education materials will be provided to all property owners/tenants. Sea Breeze Villas HOA Yes N2. Activity Restriction Within the CC&Rs language will be included to identify surface water quality protection required by HOA, Surface water quality activities will also be conducted in conformance with the SWMP as it relates to the handling and disposal of contaminants. Sea Breeze Villas HOA Yes N3. Common Area Landscape Management Monthly during regular maintenance, manage landscaping in accordance with Carlsbad Landscape Manual and with management guidelines for use of fertilizers and pesticides. Sea Breeze Villas HOA Yes N4. BMP Maintenance Inspect prior to rain season, October 1 Actual maintenance intervals to be established once system has been in operation and the rate of silt and/or debris accumulated can be qualified. Sea Breeze Villas HOA No N5. Title 22 CCR Compliance Not applicable to the project. No N7. Spill Contingency Plan Not applicable to the project. I Operations and Maintenance Plan Page 2 of 7 Sea Breeze Villas - Carlsbad, CA BMP Applicable? Yes/No BMP Name and BMP Implementation, Maintenance, and Inspection Procedures Implementation, Maintenance, and Inspection Frequency and Schedule Person or Entity with Operation & Maintenance Responsibility No N8. Underground Storage Tank Compliance Not applicable to the project. No N9. Hazardous Materials Disclosure Compliance Not applicable to the project. No N10. Uniform Fire Code Implementation Not applicable to the project. Yes N11. Common Area Litter Control Weekly sweeping and trash pick within landscape areas and outside walkways Sea Breeze Villas HOA Yes N12. Employee Training HOA through in-house seminars will provide monthly training for both maintenance personnel and employees, HOA shall be responsible for providing homeowners/tenants with educational materials regarding the impact of dumping oil, paints, solvents or other potentially harmful chemicals into storm drains; the proper use of fertilizer and pesticides in landscaping maintenance practices; and the impacts of littering and improper waste disposal. Sea Breeze Villas HOA No N13. Housekeeping of Loading Docks Not applicable to the project. Yes N14. Common Area Catch Basin Inspection Once a month to clean debris and silt of basins. Intensified around October 1^' of each year prior to "first flush" storm. Sea Breeze Villas HOA Yes N15. Street Sweeping Private Streets and Parking Lots Vacuum cleaning once a year. Sea Breeze Villas HOA No N17. Retail Gasoline Outlets Not applicable to the project. ( Operations and Maintenance Plan Page 3 of 7 Sea Breeze Villas - Carlsbad, CA structural Source Control BMPs Yes Provide Storm Drain System Stenciling and Signage Once every three months inspect for re-stenciling needs and re-stencil as necessary. Sea Breeze Villas HOA No Design and Construct Outdoor Material Storage Areas to Reduce Pollutant Introduction Not applicable to the project. No Design and Construct Trash and Waste Storage Areas to Reduce Pollutant Introduction Not applicable to the project. Yes Use Efficient Irrigation Systems & Landscape Design Once a week in conjunction with maintenance activities. Verify runoff minimizing landscape design continues to function by checking that water sensors are functioning properly, irrigation heads are adjusted properly to eliminate overspray to hardscape, and to verify that irrigation timing and cycle lengths are adjusted in accordance with water demands, given time of year, weather, and day or night temperatures. Sea Breeze Villas HOA — - No Protect Slopes and Channels and Provide Energy Dissipation Not applicable to the project. No Loading Docks Not applicable to the project. No Maintenance Bays Not applicable to the project. No Vehicle Wash Areas Not applicable to the project. No Outdoor Processing Areas Not applicable to the project. No Equipment Wash Areas Not applicable to the project. Operations and Maintenance Plan Page 4 of 7 ( Sea Breeze Villas - Carlsbad, CA No Fueling Areas Not applicable to the project. No Hillside Landscaping Not applicable to the project. No Wash Water Controls for Food Preparation Areas Not applicable to the project. No Community Car Wash Racks Not applicable to the project. Treatment Control BMPs Yes Treatment Control BMP Permeable Pavers and Baffle Box Permeable Pavers; Periodic clearing and vacuum cleaning, once a year. Baffle Box: 1 to 4 times a year determined by accumulation of sediments. Sea Breeze Villas HOA Operations and Maintenance Plan Page 5 of 7 Sea Breeze Villas - Carlsbad, CA Required Permits This section must list any permits required forthe implementation, operation, and maintenance ofthe BMPs. No permits are required for this project. Forms to Record BMP Implementation. Maintenance, and Inspection The form that will be used to record implementation, maintenance, and inspection of BMPs is attached. Recordkeeping All records must be maintained for at least five (5) years and must be made available for review upon request. Operations and Maintenance Plan Attachments RECORD OF BMP IMPLEMENTATION, MAINTENANCE, AND INSPECTION Today's Date: Name of Person Performing Activity (Printed): Signature: BMP Name (As Shown in O&M Plan) Brief Description of Implementation, Maintenance, and Inspection Activity Performed LU c re QL c 0> (0 I— 0 r— CO < § o < c C o o CL o CO 714-521-5611 BTRATA-TEC H,l NC. 562 427 8099 GEDCONSULTANTS FAX 714-521-2552 7372 Walnut Avenue, Unit F.Buena Park, California 90620 April 20, 2010 W.O. 262310 Tony Sfredo 21 Woodcrest Irvine, California, 92603 Subject: Geotechnical Engineering Investigation of Proposed Multi Family Residential Development, 391 Tamarack Avenue, Carlsbad, California. Gentlemen: Pursuant to your request, a geotechnical investigation has been performed at the subject site. The purposes ofthe investigation were to determine the general engineering characteristics ofthe soils on and underlying the site and to provide recommendations for the design of foundations, pavements and underground improvements. PROPOSED DEVELOPMENT It is our understanding that the proposed development will consist of approximately 12 attached town homes of wood-framed construction with parking and landscaping. PURPOSE AND SCOPE OF SERVICES The scope of the study was to obtain subsurface information within the project site area and to provide recommendations pertaining to the proposed development and included the following: 1. A cursory reconnaissance of the site and surrounding areas. 2. Excavation of exploratory geotechnical test pits to determine the subsurface soil and groundwater conditions. 3. Collection of representative bulk and/or undisturbed soil samples for laboratory analysis. 4. Laboratory analyses of soil samples including determination of in-situ and maximum density, in-situ and optimum moisture content, shear strength and consolidation characteristics, expansion potential and liquefaction analysis. 5. Preparation of this report presenting results of our investigation and recommendations for the proposed development. STRATA TECH, INC. GEOCQNSUUTANTS , W.O. 262310 Tony Sfredo 2 March 15 ^010 Geotechnical Engineering Investigation _ ^ ' SITE CONDITIONS The 117 by 266 foot rectangular lot is located on the south side of Tamarack Avenue, adjacent to the west side ofthe coastline raikoad tracks in Carlsbad, California. A small single story house is currently in the front ofthe lot, with a debris-covered lot in the rear. The site is shown on the attached vicinity Map, Plate No. 1. Site configuration is ftirther illustrated on the Site Plan, Plate 2. FIELD INVESTIGATION The field investigation was performed on February 26, 2010, consisting of excavating four backhoe test pits and two hand dug percolation test holes. The locations are shown on the attached Site Plan, Plate 2. As the excavation progressed, personnel from this office visually classified the soils encountered, and secured representative samples for laboratory testing. Description of the soils encountered are presented on the attached Test Pit Logs. The data presented on these logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. EARTH MATERIALS Earth materials encountered within the exploratory test pits were visually logged by a representative from STRATA-TECH, Inc. The materials were classified as artificial fill and native soils. Native soils consisted of a silty residual sandy soil to a maximum depth explored of 7 feet. Groundwater was not encountered in any of our geotechnical pits. SEISMICITY Southem California is located in an active seismic region. Moderate to strong earthquakes cari occur on numerous faults. The United States Geological Survey, CaUfomia Division of Mines and Geology private consultants, and universities have been studymg earthquakes in Southern' California for several decades. The purpose ofthe code seismic design parameters is to prevent collapse during strong ground shaking. Cosmetic damage should be expected. The principal seismic hazard to the subject property and proposed project is strong ground shaking from earthquakes produced by local faults. Secondary effects such as surface rupture, lurching, or flooding are not considered probable. STRATA-TECH, INC GEOGQNSULTANTS Tony Sfredo Geotechnical Engineering Investigation W.O. 262310 March 15.2010 2006 I.B,C. SEISMIC DESIGN VALUES 2003 NEHRP Seismic Design Provisions Site Class E - Fa = 1.0 ,Fv = 1.0 Spectral Response Accelerations Ss and SI = Mapped Spectral Acceleration Values Data are based on a 0.01 deg grid spacing Ss= 1.33 Si=0.5 Sa=.88 CONCLUSIONS AND RECOMMENDATIONS Development ofthe site as proposed is considered feasible from a soils engineering standpoint, provided that the recommendations stated herein are incorporated in the design and are implemented in the field. Recommendations are subject to change based on review of final foundation and grading plans. It is recommended that the proposed structtires be entirely supported by compacted fill. A minimum 1-foot thick compacted fill blanket below the bottom of the footings is recommended. For other minor structures such as property line walls or retaining walls less than 4 feet high, competent native soils or compacted fill may be used for structural support. PROPOSED GRADING Grading plans were not available at the time our work was performed. It is assumed that proposed grades will not differ significantly from existing grades. The following recommendations are subject to change based on review of final grading plans. GRADING RECOMMENDATIONS Removal and recompaction of existing fill and loose native soils will be required to provide adequate support for foundations and slabs on grade. The depth of removal shall be 1 foot below the bottom ofthe footings. The depth of removal is estimated to be at least 3 feet. Earthwork for foundation support shall include the entire building pad and shall extend a minimum of 5 feet outside exterior footing lines where feasible or to property line. While no structures are on adjacent properties care shall be exercised not to undermine adjacent hardscape, walls, or pavements. STRATA TECH, INC GEQCDNSUL.TANTS Tony Sfredo Geotechnical Engineering Investigation W.O. 262310 March 15.2010 The exposed excavation bottom shall be observed and approved by STRATA-TECH, Inc. and the City's grading inspector prior to processing. Dependent on field observations, removals may be adjusted up or down. Subsequent to approval of the excavation bottom, the area shall be scarified 6 inches, moisture conditioned as needed, and compacted to a minimum of 90 percent relative compaction. Fill soils shall be placed in 6 to 8 inch loose lifts, moisture conditioned as needed, and compacted to a minimum of 90 percent relative compaction. This process shall be utilized to finish grade. Grading for hardscape areas shall consist of removal and recompaction of soft surficial soils. Removal depths are estimated at 1 to 2 feet. Earthwork shall be performed in accordance with previously specified methods. Grading and/or foundation plans shall be reviewed by the soil engineer. All recommendations are subject to modification upon review of such plans. FOUNDATIONS ON COMPACTED FILL The proposed building may be supported by continuous spread and isolated footings placed a minimum depth of 24 inches below lowest adjacent grade utilizing an allowable bearing value of 2,000 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. Type Minimum Depth (inches) Minimum Width (inches) Bearing Value (psf) Increase Maximum (psf) Type Minimum Depth (inches) Minimum Width (inches) Bearing Value (psf) Width Depth Maximum (psf) Type Minimum Depth (inches) Minimum Width (inches) Bearing Value (psf) (psfi'ft) (psf/ft) Maximum (psf) Continuous 24 12 2000 180 440 3500 Interior Pad 18 24 2000 180 440 3500 It is recommended that all footings be reinforced with a minimum of two no. 4 bars (1 top and 1 bottom). The structural engineer's reinforcing requirements should be followed if more stringent. Footing excavations shall be observed by a representative of STRATA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed mitigation will be recommended. FOUNDATIONS ON COMPETENT NATIVE SOILS - for Minor Structures Minor structures may be supported by continuous spread footings placed a minimum depth of 24 inches below lowest adjacent grade and 12-inches into natural soil utilizing an allowable STRATA-TECH, INC GEDCONSULTANTS Tony Sfredo Geotechnical Engineering Investigation W.O. 262310 March 15.2010 bearing value of 1,500 pounds per square foot. This value is for dead plus live load and may be increased 1/3 for total including seismic and wind loads where allowed by code. Footing excavations shall be observed by a representative of STRATA-TECH, Inc. prior to placement of steel or concrete to verify competent soil conditions. If unacceptable soil conditions are exposed, mitigation will be recommended. LATERAL DESIGN Lateral restraint at the base of footings and on slabs may be assumed to be the product ofthe dead load and a coefficient of friction of .30. Passive pressure on the face of footings may also be used to resist lateral forces. A passive pressure of zero at the surface of fmished grade, increasing at the rate of 300 pounds per square foot of depth to a maximum value of 2,500 pounds per square foot, may be used for compacted fill or native soils at this site. If passive pressure and friction are combined when evaluating the lateral resistance, the value of the passive pressure should be limited to 2/3 of the values given above. RETAINING WALLS Unrestrained walls up to 5-feet in height retaining drained earth may be designed for the following: Surface Slope of Retained Material Horizontal to Vertical Equivalent Fluid Pressure Pounds Per Cubic Foot Level 30 5 to 1 32 4 to 1 35 3tol 38 2 to 1 43 These values include seismic loading. Backfill should consist of clean sand and gravel. While all backfills should be compacted to the required degree, exfra care should be taken working close to walls to prevent excessive pressure. Retaining walls should include subdrains consisting of 4-inch, SCH 40 or SDR 35 perforated pipe surrounded by 1 cubic foot per lineal foot of crushed rock. All wall backfill should be compacted to a minimum of 90 percent relative compaction. All retaining structtires should include appropriate allowances for anticipated surcharge loading, where applicable. In this regard, a uniformly distributed horizontal load equal to one-half the vertical surcharge shall be applied when the surcharge is within a horizontal distance equal to the wall height. Retaining wall footing excavations shall be founded entirely in competent native soils or compacted fill. Footing bottoms shall be observed by a representative of STRATA-TECH, Inc., to verify competent conditions. STRATA-TEC H,INC. GEOCON SULTANTS Tony Sfredo 6 "^-p'-^SIS Geotechnical Engineering Investigation March 15,2010 EXPANSIVE SOILS Results of expansion tests indicate that the near surface soils have a low expansion potential. SETTLEMENT The maximum total post-construction settlement is anticipated to be on the order of 1/2 inch. Differential settlements are expected to be less than 1/2 inch, measured between adjacent structural elements. SUBSIDENCE & SHRINKAGE Subsidence over the site during grading is anticipated to be on the order of .5 feet. Shrinkage of reworked materials should be in the range of 10 to 15 percent. FLOOR SLABS The surface soils are non-plastic with low expansion potential. Where concrete slabs on grade are utilized, the slab shall be supported on at least 1 foot of engineered fill compacted to a minimum of 90 percent relative compaction. Slabs should be at least 4 inches thick and reinforced with a minimum of no. 3 bars 24 inches on center both ways. The soil should be kept moist prior to casting the slab. However, if the soils at grade become disturbed during construction, they should be brought to approximately optimum moisture content and rolled to a firm, unyielding condition prior to placing concrete. In areas where a moisture sensitive floor covering will be used, a vapor barrier consisting of a plastic film (6 ml polyvinyl chloride or equivalent) should be used. The vapor barrier should be properiy lapped and sealed. Since the vapor barrier will prevent moisttire from draining from fresh concrete, a better concrete finish can usually be obtained if at least 2 inches of wet sand is spread over the vapor barrier prior to placement of concrete. UTILITY LINE BACKFILLS All utility line backfills, both interior and exterior, shall be compacted to a minimum of 90 percent relative compaction and shall require testing at a maximum of 2-foot vertical uitervals. STRATA-TECH, INC. GEDGDN SULTANTS Tony Sfredo , W.O. 262310 Geotechnical Engineering Investigation March 15,2010 HARDSCAPE AND SLABS Hardscape and slab subgrade areas shall exhibit a minimum of 90 percent relative compaction to a depth of at least 1 foot. Deeper removal and recompaction may be required if unacceptable conditions are encountered. These areas require testing just prior to placing concrete. STORMWATER INFILTRATION TEST RESULTS Two 3 foot deep Hand Dug test pits were excavated in the central driveway portion ofthe site on April 20, 2010. The diameter of the test hole was 6-inches. The lower depth ofthe pit exposed a natural soil layer of loose medium grained brown Silty SAND that is typical of the underlying soils. The bottom of the test pit was saturated and tested the following morning. The percolation test was performed by siphoning a 5-gallon water bottle into the hand-dug hole. The water level was kept at 5 to 6 mches in depth for a period of four hours. At the end of four hours, the time for the water to drop from the 6"^ to the 5* inch was measured. This value was 15 minutes for both holes. This corresponds to a percolation rate of 15 gallons per square foot of sidewall soil per day. The percolation rate can be expected to perform at the tested rate over a short period of time with clean water flowing into undisttirbed soil. A high factor of safety should be used for longer-term use with unfiltered water. The percolation rate can be expected to increase at a power of 1.5 with respect to head increase. DRAINAGE Positive drainage should be planned for the site. Minimum drainage should be 2 percent for landscape areas and 1 percent for hardscape. Drainage should be directed away from structures via non-erodible conduits to suitable disposal areas. The structtire should utilize roof gutters and down spouts tied directly to yard drainage. Unlined flowerbeds, planters, and lawns should not be constructed against the perimeter of the structure. If such landscaping (against the perimeter of a structure) is planned, it should be properly drained and lined or provided with an underground moisture barrier. Irrigation should be kept to a minimum. This report is issued with the understanding that it is the responsibility of the owner, or of his representative, to ensure that the information and recommendations contained herein are called to the attention ofthe engineers for the project and incorporated into the plans and that the necessary steps are taken to see that the Contractors and Subcontractors carry out such recommendations in the field. STRATA-TECH, INC. GEOGQNSULTANTS , W.O. 262310 Tony Sfredo 8 March 15.2010 Geotechnical Engmeenng Investigation—__ . ENGINEERING CONSULTATION, TESTING & OBSERVATION We will be pleased to provide additional input with respect to foundation design once methods of construction and/or nattire of imported soil has been determined. Grading and foundation plans should be reviewed by this office prior to commencement of grading so that appropriate recommendations, if needed, can be made. Areas to receive fill should be inspected when unsuitable materials have been removed and prior to placement of fill, and fill should be observed and tested for compaction as it is placed. AGENCY REVIEW All soil geologic and sfructtiral aspects ofthe proposed development are subject to the review and approval of the governing agency(s). It should be recognized that the governing agency (s) can dictate the manner in which the project proceeds. They could approve or deny any aspect of the proposed improvements and/or could dictate which foundation and grading options are acceptable. Supplemental geotechnical consulting in response to agency requests for additional information could be required and will be charged on a time and materials basis. LIMITATIONS This report presents recommendations pertaining to the subject site based on the assumption that the subsurface conditions do not deviate appreciably from those disclosed by our exploratory excavations. Our recommendations are based on the technical information, our understanding of the proposed constrtiction, and our experience in the geotechnical field. We do not guarantee the performance ofthe project, only that our engineering work and judgments meet the standard of care of our profession at this time. In view ofthe general conditions in tiie area, the possibility of different local soil conditions may exist Aay deviation or unexpected condition observed during constiuction should be brought to the attention ofthe Geotechnical Engineer. In tiiis way, any supplemental recommendations can be made with a minimum of delay necessary to the project. If the proposed construction will differ from our present understanding ofthe project, the existing information and possibly new factors may have to be evaluated. Any design changes and the finished plans should be reviewed by the Geotechnical Consultant. Of particular importance would be extending development to new areas, changes in strticttiral loading conditions, postponed development for more than a year, or changes in ownership. STRATA-TECH, INC GEQGONSULTANTS Tony Sfredo Geotechnical Engineering Investigation W.O. 262310 March 15.2010 This report is issued with tiie understanding that it is tiie responsibility of tiie owner, or ol his representative, to ensure tiiat tiie information and recommendations contained herein are called to the attention ofthe Architects and Engineers for tiie project and incorporated into the plans and that the necessary steps are taken to see that the contractors and subcontractors carry out such recommendations in the field. This report is subject to review by the contt-olling autiiorities for tiiis project. We appreciate this opportunity to be of service to you. Respectftilly submitted: STRATA-TECH, Inc. Roland .A,cuna, PG Principal Larry Finley KCli 46606 Enclosures: Plate 1: Vicinity Map Plate 2: Site Plan and Boring Location Map Test Pit Logs Appendix A: Laboratory Results and Engineering Calculations Appendix B: Specifications for Grading VICINITY MAP S21 Pacific Ocean 7»M f^m Or Copyright 0 2005 Mcrosoft Corp. and/or its suppliers, fitt rights reserved. Geotechnical Engineering Investigation 391 Tamarack Avenue Carlsbad, California Work Order 262310 Plate No. STRATA - TECH, INC. TRENCH LDCATinN PLAN 39! TAMARACK AVrNUE, CARLSBAD, CA scole: 1" = 20'-0" Kyi Site Plan 10.7 12~unit Townhome Project: Ave, Carlsbod, CA 120 160 .391 Tamarack ("Ul T-3 LEGEND 5,500 sail TEST PIT LOCATION PERCOLATION TEST PIT LOCATION RECORD OF SUBSURFACE EXPLORATION Ul )isture % 1 dry wt,) 'E Date 2/25/2010 Geotechnical Engineering Investigation ampli )isture % 1 dry wt,) Dry Des (pcf) SI Q. 391 Tamarack Avenue Dry Des (pcf) Q) Q Carlsbad, California U B Work Order 262310 Test Pit No. 1 Description of Earth Materials 6 114 0 2 4 6 — 8 — 0- 2', TOPSOIL, MOIST, SMALL ROOTS 2- 6', : ORANGE-BROWN F-MED GR. SAND DRY 6-8', SOIL, M-F GR. SILTY SAND , DAMP DENSE End of Test Pit at 8' Feet. No Ground Water. No Caving. RECORD OF SUBSURFACE EXPLORATION sture % dry wt,) r- Date 2/25/2010 Geotechnical Engineering Investigation CD Q. E sture % dry wt,) Desi (pcf) LL. -•—• 391 Tamarack Avenue Q a> Q C/5 Q a> Q Carlsbad, California u B Work Order 262310 Test Pit No. 2 Description of Earth Materials n SURFACE: WEED COVERED YARD u 0-6" TOPSOIL, BROWN SILTY SAND WITH SMALL ROOTS 1 — 6-24": LIGHT BROWN NATURAL SOIL F-MED GR SAND 1 — FAIRLY DENSE WITH SOME CLAY BINDER: MOIST 2 — 24-36" NATURAL SOIL.BROWN SILTY SAND WITH 3 SHARP GRAVELS, COHESIONLESS 4 — End of Test Pit at 3 Feet. No Ground Water. No Caving. STRATA - TECH, INC. NEAR SOURCE FAULT MAP Geotechnical Engineering Investigation 391 Tamarack Avenue Carlsbad, California Work Order 262310 Plate No. STRATA - TECH, INC. STRATA-TEC H,INC BEOCONSULTANTS APPENDIX A This appendix contains a description of the field investigation, laboratory testing procedures and results, site plan, and exploratory logs. FIELD INVESTIGATION The field investigation was performed on February 26, 2010, consisting of the excavation of four exploratory trenches at locations shown on the attached Site Plan, Plate 2. As excavation progressed, personnel from tiiis office visually classified the soils encountered, and secured representative samples for laboratory testing. Sample Retrieval- Backhoe Undisturbed samples of earth materials were obtained at frequent intervals by driving a thin- walled steel sampler by the hydraulic action ofthe backhoe bucket. The material was retained in brass rings of 2.41 inches inside diameter and 1.00 inch height. The central portion ofthe sample was in close-fitting, watertight contamers for transportation to the laboratory. Descriptions of the soils encountered are presented on tiie attached boring Logs. The data presented on tiiese logs is a simplification of actual subsurface conditions encountered and applies only at the specific boring location and the date excavated. It is not warranted to be representative of subsurface conditions at other locations and times. Laboratory Testing Field samples were examined in the laboratory and a testing program was then established to develop data for preliminary evaluation of geotechnical conditions. Moisture Density Field moisture content and dry density were determined for each ofthe undisturbed soil samples. The dry density was determined in pounds per cubic foot. The moisture content was determined as a percentage ofthe dry soil weight. The results of tiie tests are shown in tiie test results section of this appendix. Compaction Character Compaction tests were performed on bulk sample of tiie existing soil in accordance with ASTM DI 557-07. The results ofthe tests are shown in tiie test results section of tiiis appendix. Shear Strength The ultimate shear strengths ofthe soil, remolded soil, highly weatiiered bedrock and bedrock was determined by performing direct shear tests. The tests were performed in a strain-controlled STRATA-TECH, INC GEOCON U U T A N T S machine manufactured by GeoMatic. The rate of deformation was 0.005 inches per minute. Samples were sheared imder varying confining pressure, as shown on the "Shear Test Diagrams". The samples indicated as saturated were artificially saturated in the laboratory and were shear under submerged conditions. The results of tests are based on 80 percent peak sttength or ultimate strength, whichever is lower, and are attached. In addition, a shear was performed on an upper layer sample remolded to 90-percent of the laboratory standard with low confining pressure. TEST RESULTS Maximum Density/Optimum Moisture (ASTM:D-1557-07) Trench Depth in Feet Maximum Density (pcf) Optimum Moisture (%) 3 1-3 124 12.0 In-Situ Dry Density/ Moisture Trench Depth in Feet Dry Density (pcf) Moisture (%) 1 3.5 114.0 6.1 3 4 114.1 6.0 3 9 113.7 5.8 Direct Shear Trench Depth in Feet Cohesion (psf) Angle of Intemal Friction (degrees) 3 4 200 30 ALLOWABLE BEARING CAPACITY Reference: "Soil Mechanics in Engineering Practice", Terzaghi and Peck, 1967 pages 222 and 223. Bearing Material; compacted fill Properties: Wet Density ( ) = 130 pcf Cohesion (C) = 200 psf Angle of Friction ( ) = 30 degrees Footing Depth (D) = 2 feet Footing Width (B) = 1.0 foot Factor of Safety = 3.0 Calculations - Ultimate Bearing Gapacitv from figure 33.4 on page 222 Nc= 30.14 Nq= 18.4 N = 22.4 Qu = 1.2 C Nc + D Nq + 0.4 B N (Square Footing) = 1.2 * 200 * 30.14-H30*2* 18.4 •^ 0.4* 130*1 *22.4 = 7233+4784+ 1164= 13181 psf Allowable Bearing Capacity for Square Footing Qaii= Qu/F.S. = 4393 psf Use 1500 psf (Settlement Control) Qu = 1.0 C Nc + D Nq + 0.5 B N (Continuous Footing) = 1.0*200*30.14 + 130*2*18.4 + 0.5*130*1 *22.4 = 6028 + 4784 + 1456 = 12268 psf Allowable Bearing Capacity for Continuous Footing Qai,= Qu/F.S. = 4089 psf Use 1500 psf (Settlement Control) Increases: 440 psf / ft in depth over 2 feet 0 psf / ft in depth over 1 foot Geotechnical Engineering Investigation 391 Tamarack Avenue Carlsbad, California Work Order 262310 Geotechnical Engineering Investigation 391 Tamarack Avenue Carlsbad, California STRATA - TECH, INC. ACTIVE RETAINING WALL PRESSURE Proposed Pool WALL Free Body Diagram PA 0.13 kef 0.2 ksf = 45 + ^/2 W = a + b Cm = C / F.S. = 0.1 ksf m = tan""" (tan / F.S.) = 16.1 degrees D = (H-Hc)tan(90 - )= 2.26ft L = (( H - He) ^ + D ') ''^ = 3.76 ft W = A „ = 0.5D(H + Hc) 1.03 kips/LF a = Cm L sin ( 90 + „ ) / sin ( - ^ ) = 0.6 kips/LF b = W-a= 0.43 kips/LF PA = btan( - ^)= 0.32 kips/LF Design EFP = 2 PA / H ^ = 25.6 pcf Use 26 pcf (30 min.) Geotechnical Engineering Investigation 391 Tamarack Avenue Carlsbad, California Work Order 262310 STRATA - TECH, INC. STRATA-TECH, INC BEOCONSULTANTS APPENDIX B SPECIFICATIONS FOR GRADING SITE CLEARING All existing vegetation shall be stripped and hauled from the site. PREPARATION After the foundation for the fill has been cleared, plowed or scarified, it shall be disced or bladed until It is uniform and free from large clods, brought to a proper moisttire content and compacted to not less than 90 percent of tiie maximum dry density in accordance with ASTM:D-1557-02 (5 layers - 25 blows per layer; 10 lb. hammer dropped 18"; 4" diameter mold). MATERIALS On-site materials may be used for fill, or fill materials shall consist of materials approved by the Soils Engineer and may be obtained from tiie excavation of banks, borrow pits or any other approved source. The materials used should be free of vegetable matter and other deleterious substances and shall not contain rocks or lumps greater tiian 8 inches in maximum dimension. PLACING, SPREADING, AND COMPACTING FILL MATERIALS \\Tiere natural slopes exceed five horizontal to one vertical, tiie exposed bedrock shall be benched prior to placing fill. The selected fill material shall be placed in layers which, when compacted, shall not exceed 6 inches in thickness. Each layer shall be spread evenly and shall be thoroughly mixed during the spreading to ensure uniformity of material and moisture of each layer. Where moisture of the fill material is below tiie limits specified by the Soils Engineer, water shall be added until the moisttire content is as requked to ensure thorough bonding and thorough compaction. ° Where moisture content of the fill material is above tiie limits specified by the Soils Engineer, the fill materials shall be aerated by blading or otiier satisfactory metiiods until tiie moisture content is as specified. After each layer has been placed, mbced and spread evenly, it shall be tiioroughly compacted to not less than 90 percent ofthe maximum dry density in accordance witii ASTM:D-1557-02 (5 layers - 25 blows per layer; 10 lbs. hammer dropped 18 inches; 4" diameter mold) or other density tests which will attain equivalent results. STRATA-TEC H,INC BEOCONSULTANTS Compaction shall be by sheepsfoot roller, multi-wheel pneumatic tire roller or other types of acceptable rollers. Rollers shall be of such design that tiiey will be able to compact the fill to tiie specified density. Rolling shall be accomplished while tiie fill material is at the specified moisture content. Rolling of each layer shall be continuous over the entire area and the roller shall make sufficient trips to ensure that the desired density has been obtained. The final surface ofthe lot areas to receive slabs on grade should be rolled to a dense, smooth surface. T!ie outside of all fill slopes shall be compacted by means of sheepsfoot rollers or other suitable equipment. Compaction operations shall be continued until tiie outer 9 inches of the slope is at least 90 percent compacted. Compacting of the slopes may be progressively in increments of 3 feet to 5 feet of fill height as the fill is brought to grade, or after the fill is brought to its total height. Field density tests shall be made by the Soils Engineer of the compaction of each layer of fill. Density tests shall be made at intervals not to exceed 2 feet of fill height provided all layers are tested. Where the sheepsfoot rollers are used, tiie soil may be disturbed to a deptii of several inches and density readings shall be taken in tiie compacted material below the disturbed surface. When these readings indicate that the density of any layer of fill or portion there is below the required 90 percent density, the particular layer or portion shall be reworked until tiie required density has been obtained. The grading specifications should be a part of the project specifications. The Soil Engineer shall review the grading plans prior to grading. INSPECTION The Soil Engineer shall provide continuous supervision of the site clearing and grading operation so that he can verify the grading was done in accordance with the accepted plans and specifications. SEASONAL LIMITATIONS No fill material shall be placed, spread or rolled during unfavorable weather conditions. When work is interrupted by heavy rains, fill operations shall not be resumed until the field tests by the Soils Engineer indicate the moisture content and density of the fill are as previously specified. EXPANSIVE SOIL CONDITIONS Whenever expansive soil conditions are encountered, the moisture content of the fill or recompacted soil shall be as recommended in the expansive soil recommendations included herewith. 3 o L_ T3 Hydrology Study Sea Breeze Villas Project No. CT 10-01 Carlsbad, California Prepared For: TMS Development, LLC 32 Sylvan Irvine, Califomia 92603 Prepared By: Surender Dewan, P.E. DMS Consultants, Inc. 12371 Lewis Street, Suite 203 Garden Grove, California 92840 714.740.8840 August 12,2010 CONSULTANTS, INC. civil. ENGINEERS SEA BREEZE VILLAS CARLSBAD Site Description The proposed project is located in the City of Carlsbad on the south side of Tamarack Avenue, at 391 Tamarack Avenue on a 0.70 acre site. The proposed project is a 12-unit airspace condominium project. Purpose The purpose of this study is to determine the total runoff generated for a storm of six (6) hour duration for one hundred (100) year frequency and design an infiltration system to store the increase in volume of runoff between the pre and post runoff condition. For overflow conditions a 12-inch diameter PVC pipe has been installed, this overflow pipe connects to an existing catch basin located along the southerly curb of Tamarack Avenue. Section 1.0 100 Year Hydrology Calculations 1.1 Rainfall The 100 year 6 hr rainfall depth was taken from the San Diego County Hydrology Manual isopluvial maps. Figure 1 below is an enlarged copy of the applicable section of the map. 1.1.1 1.1.2 Existing Condition Rainfall Rainfall for the existing condition was taken from the Manual. Proposed Condition Rainfall The total 100 year storm depth for the proposed condition was calculated by subtracting the Water Quality Depth (see below) from the 100 year storm total total from the Manual. <6 1 3 f J 3 . • • * /..; \ \- * * * t •i • - .- X, \ / - '• • r Jl • 1 1 # If ' j • % * At V • * \ '* a yt j k a OCEANSIC E yt j k \\\t f' -• • < -,ARl .'iBAD ^ • •t < \ Figure 1 100 Year 6hr Isopluvia is 1.2 Soil Type The hydrologic soil type for the area of the proposed tract is listed as "B" in the Manual Appendix A. Runoff Coefficients Runoff coefficients for the pre and post project condition were taken from Table 3-1 ofthe Hydrology Manual. (See attached table 3-1.) 1.3 Time of Concentration (Tc) 1.3.1 Existing Condition Tc The lot currently drains, via overland flow, to the northwest with an average slope of 2%. The iniital time of concentration (Ti) was estimated using Table 3-2 of the Hydrology Manual (See attached Table 3-2). CARLSBAD Figure 2 Soil Type The Tt for the rest of the flow distance was estimated Manning's equation assuming a broad open swale with a 20:1 side slope to calculate the flow velocity. See the attached hydraulic calculations for the swale travel time. 1.3.2 Proposed Condition Tc In the proposed condition the lots drain to a paver swal in the center of the tract wnich conveys the flows to the north east corner of the lot. The flows then enter a storm drain pipe and are conveyed to the existing inlet in Tamarack Avenue. The initial Ti was estimated using Table 3-2 ofthe Hydrology Manual. The velocity in the swale was estimated using Manning's equation and the velocity in the pipe was calculated using V = Q/A and assuming the pipe will be flowing full. Section 2.0 Storm Water Quality Calculations 2.1 Rainfall The storm water quality treatment volume was taken from the Manual Appendix E. Figure 3 is an enlarged copy ofthe applicable section of the map. 2.2 Storage The required storage was calculated using the pre and post project runoff coefficients from the Manual and determining the incremental increase in the storm water yeild for the water quality depth. The size of the paver area and the depth of the gravel subbase were set so that the entire incremetal increase in the storm water quality runoff could be stored in the gravel subbase. (See the attached storm water quality calculations) 2.3 Infiltration The geotechnical evaluation ofthe site yielded a percolation rate of 15 gallons per day per square foot or 2.003 cubic feet per day per square foot. The required infiltration time was calculated by dividing the required storage by the area of the paver swale and the rate of percolation for the geotechnical analysis. See the attached calculations for the results of the analysis. Figure 3 Storm Water Quality Depth Graded Area 85th Percentile Depth Soil Group Pre Project Runnoff Coefficient "C" Post Project Project Runnoff Coefficient "C" Storm Water Qualitv Volume Pre Project 85th Percentile Runoff Volume Post Project 85th Percentile Treatment Runoff Volume Required Infiltration Volume (LID) Design for Infiltration of Treatment Volume Available Storage Paver Length Paver Width Paver Area Gravel Subbase Depth Porosity Total Storage Volume Available Time for Complete Infiltration Infiltration Area Infiltration Rate Infiltration Rate Total Infiltration Per Day Total Infiltration Per Hour Required Infiltration Time Value 30100 0.61 B 0.25 0.58 382.52 887.45 504.9275 887.45 285 8 2280 12 0.4 912 2280 15 2.003 4566.09 190.25 4.66 in ft'^3 ft'^3 ff^S ft ft ft'^2 in ft'^3 > 887 OK ft^2 gal/day/square foot cubic feet /day / square foot cubic feet/ day cubic feet/hour hours < 72 Hours OK ( Site Data ICraded Area jSoil Group jPre Project Runnoff Coefficient "C" jPost Project Project Runnoff Coefficient "C" 100 Year Hydrology Calculations for Seabreeze Villas Value Units 30100 sf B 0.25 0.58 Pre Proiect 100 vpar 6hr Runoff jPre Project Ti lEarth Swale Length I Earth Slope lEarth Swale Z lEarth Swale N lEarth Swale Flow Depth lEarth Swale Velocity [Earth Swale Tt JTC = Ti + Tt llOO year6 hr Depth jlOOyeare hr Intensity 1100 Year flow rate [Post Proiect 100 vear 6hr Runoff I Post Project Ti IPaver Swale Length IPaver Slope J Paver Swale Z jPaver Swale N [Paver Swale Flow Depth I Paver Swale Velocity (Paver Swale Tt IPipe Size I Pipe Length IPIpe Velocity (Assume pipe flows full) iPlpeTt Total Tt Tc llOO year 6 hr Depth Infiltration Depth (See Storm Water Calculations) [Effective 100 6hr Depth llOO year 6 hr intensity llnfiltration Area Graded Area Less Infiltration Area 100 Year flow rate 10.90 min 210.00 ft 0.020 percen 20.00 0.025 0.210 ft 0.56 ft/sec 6.24 min 17.14 min 2.50 in 2.98 in/hr 0.51 cfs 8.20 min 235.00 ft 0.005 percent 50.00 0.02 0.155 ft 0.75 ft/sec 5.24 min 12.00 in 275.00 ft 1.04 ft/sec. 4.39 min 9.63 min 17.83 min 2.50 in 0.61 in 1.89 in 2.19 in/hr 2280.00 ft'^2 27820.00 ft^2 0.81 cfs 100 Year Swale Velocity Caicuiations for Seabreeze Villas Paver Swale depth n b zl z2 area wp r r'^2/3 s s'^.5 q VEL 0.15 0,015 0 50 50 1.125 15.003 0.074985 0.177821 0.0018 0.042426 0.840813 0.747389 Natural Swale depth n b zl z2 area wp r r'^2/3 s 5-^.5 q VEL 0.21 0.025 0 20 20 0.882 8.410493 0.104869 0.222381 0.0018 0.042426 0.494631 0.560807 SAN DIEGO HYDROLOGY MANUAL (ATTACHMENTS) Table 3.1 and Table 3.2 San Diego County Hydrology Manual Date; June 2003 Section: Page: 3 6 of 26 Table 3-1 RUNOFF COEFFICIENTS FOR URBAN AREAS Land Use Runoff Coefficient "C" NRCS Elements County Elements Soil Type % IMPER. Undisturbed Natural Terrain (Natural) Low Density Residential (LDR) Low Density Residential (LDR) Low Density Residential (LDR) Medium Density Residential (MDR) Medium Density Residential (MDR) Medium Density Residential (MDR) Medium Density Residential (MDR) High Density Residential (HDR) High Density Residential (HDR) Commercial/Industrial (N. Com) Commercial/Industrial (G. Com) Commercial/Industrial (O.P. Com) Commercial/Industrial (Limited L) Commercial/Industrial (General L) Permanent Open Space Residential, 1.0 DU/A or less Residential, 2.0 DU/A or less Residential, 2.9 DU/A or less Residential, 4.3 DU/A or less Residential, 7.3 DU/A or less Residential, 10.9 DU/A or less Residential, 14.5 DU/A or less Residential, 24,0 DU/A or less Residential, 43.0 DU/A or less Neighborhood Commercial General Commercial Office Professional/Commercial Limited Industrial General Industrial 0* 10 20 25 30 40 45 50 65 80 80 85 90 90 95 0.20 0.27 0.34 0.38 0.41 0.48 0.52 0.55 0.66 0.76 0.76 0.80 0.83 0.83 0.87 0.25 0.32 0.38 0.41 0.45 0.51 0.54 0.58 0.67 0.77 0.77 0.80 0.84 0,84 0.87 Pre Project 0.36 0.42 0,45 0.48 0.54 0.57 Post Project 0.69 0,78 0.78 0.81 0.84 0,84 0,87 0,35 0.41 0.46 0.49 0.52 0.57 0.60 0.63 0,71 0.79 0,79 0.82 0,85 0,85 0,87 DU/A - dwelling units per acre NRCS = National Resources Conservation Service 3-6 San Diego County Hydrology Manual Date: June 2003 Section; Page: 12 of 26 Note tiiat the Initial Time of Concentration should be reflective ofthe general land-use at the upstream end of a drainage basin. A single lot witii an area of two or less acres does not have a significant effect where the drainage basin area is 20 to 600 acres. Table 3-2 provides limits ofthe lengtii (Maximum Length (LM)) of sheet flow to be used in hydrology studies. Initial Ti values based on average C values for the Land Use Element are also mcluded. These values can be used m plamiing and design applications as descnbed below. Exceptions may be approved by the "Regulating Agency" when submitted with a detailed study. Table 3-2 MAXIMUM OVERLAND FLOW LENGTH (LM) Element* Natural & INITUL TIME OF CONC DU/ Acre LDR LDR LDR MDR MDR MDR MDR HDR HDR N. Com G. Cora 2.9 4.3 .5% 50 50 50 50 7.3 10.9 14.5 24 43 O.P./Com Limited I. General I. 50 50 Ti 13.2 12.2 11.3 10.7 10.2 50 50 9.2 :.7 50 50 50 50 50 50 50 6.7 5.3 5.3 4.7 4.2 4.2 3.7 1% L 70 70 70 12.5 11.5 10.5 70 70 65 65 165 65 65 60 60 60 60 60 10.0 9.6 8.4 2% LM 85 85 85 85 80 80 7.9 6.1 4.7 4.5 4.1 3.7 3.7 80 -80- 75 Ti 10.9^^tO^ 10.0 9.2 8.8 8.1 7.4 6.9 -6:5- 5.1 :NTRATION m 3% 100 100 95 95 95 90 -9&- 75 75 75 70 3.2 70 70 *See Table 3-1 for more detailed description 4.0 4.0 3.6 3.1 3.1 2.7 90 85 85 Ti 9.5 8.8 8.1 7.8 7.0 6.4 5% Ti 100 100 100 100 100 4.9 3.8 85 80 80 80 3.8 3.4 2.9 2.9 2.6 100 -tm- 8.0 7.4 10% L •M -tm- 100 100 7.0 6.7 6.0 5.7 95 4.3 100 T, Ti Pre Project 6.4 5.6 100 100 100 -tm 95 95 90 90 90 90 3.4 3.4 2.9 2.6 2.6 2.3 100 100 100 100 100 100 100 5.3 4.8 4.5 Ti Post Projec 3.5 2.7 2.7 2.4 2.2 2.2 1.9 3-12 riirzi: SCALE: 1"=30' DMS INI VICINITY MAP NTS LEGEND AREA DISCRIPTION AREA IN ACRES (JOI^ NODE NUMBER CONSULTANTS. INC. CIVIL ENGINEERS 12371 Lewis St Garden Grove CA. 92840 P. 71+-740-8840 F. 714-740-8842 HYDROLOGY PLAN EXISTING CONDITIONS SEABREEZE VILLAS CARLSBAD, CALIFORNIA 7—r tSaaaai'-.aa'.'i •aa^aaia'^ari 'iiiaiiiaaiiiiii««iiii"i ]} I mm. mm m .„.,„i L L VICMTY MAP LEGEND AREA DISCRIPTION AREA IN ACRES CjoT) NODE NUMBER SCALE: 1"=30' DMS CONSULTANTS. INC. CIVIL ENGINEERS 12371 Lewis St #203 Garden Grove OA. 92840 P. 714-740-8840 F. 714-740-8842 HYDROLOGY PLAN PROPOSED CONDITIONS SEABREEZE VILLAS CARLSBAD, CALIFORNIA X o CQ tt (0 m T3 C CO > < S E a. UJ FIND A MANUFACTURER PERMEABLE PAVERS ECO-STONE* TRADITIONAL PAVERS PROJECT GALLERY DESIGN & INSTAILATION DESIGN PROFESSIONALS CONTRACTORS REFERENCE & RESEARCH DOWNLOADS EXPOS & EDUCATION INFORMATIONAL LINKS WHAT'S NEW Eco-Stone Design Guide and Research Siimmarv... Newly Updated! This comprehensive guide has been updated to 60 pages with new design, construction and research infornnation...Learn more. UNI ECO-STONE® FAMILY OF PERMEABLE PAVERS UNI-GROUP U.S.A. first brought UNI Eco-Stone® to North America in 1989, well before permeable Interlocking concrete pavers became popular As leaders in the Industry, we recognized the possibilities and environmental benefits of being able to Infiltrate water through the pavement surface into the ground below. With the advent ofthe Environmental Protection Agency's (EPA) mandate to control stormwater runoff through it's National Pollutant Discharge Elimination System (NPDES) in the early 90's, the path was paved for the growth of permeable pavements. The EPA is now working in conjunction with other agencies and organizations such as the Low Impact Development Center, the U.S. Green Building Council, and the Center fbr Watershed Protection to promote the use of low impact development (LID) and LEED and Smart Growth as a way to manage runoff. The EPA plans to establish ordinances to move the program in the direction of preferred design and best management practices. Infiltration practices have emerged as a major focus of these agencies and Eco-Stone® permeable interlocking concrete pavements utilize infiltration to control stormwater runoff. Click here for a list of federal, state and municipal approvals of permeable pavements and Eco- Stone®. FEATURES & BENEFITS OF ECO-STONE® PERMEABLE INTERLOCKING CONCRETE PAVERS • Can be designed to accommodate a wide variety of stormwater management objectives • Runoff reductions of up to 100% depending on project design parameters • Maximizes groundwater recharge and/or storage • Allows for retention and storage of stormwater for possible re-use for irrigation or other non-potable uses • Reduces nonpoint source pollutants in stormwater, thereby mitigating impact on surrounding surface waters, and may lessen or eliminate downstream fiooding and stream bank erosion • Minimizes impacts and stress on existing storm sewer systems through reduced peak discharges • Allows better land-used planning and more efficient use of available land for greater economic value, especially in high-density, urban areas • May decrease projects cost by reducing or eliminating drainage and retention/detention systems • May reduce cost of compliance with stormwater regulatory requirements and lower utility fees • May reduce heat island effect and themnal loading on surround surface waters For more information on the Eco-Stone® Family of Permeable Pavers, please click on the quick links provided in the menu at left or in the side bar at right. While Eco-Stone® Is available at all UNI Manu^cturer locations, a number of the newer products may not be available in all areas. Please check with your manufacturer for availability. UNI ECO-STONE® The original UNI Eco-Stone® paver has become the pemfieable paver of choice fbr design professionals. The classic shape provides structural interlock to provide a strong, durable pavement surface under vehicular traffic, yet allows for the infiltration of stormwater for environmental benefit. UNI ECO-STO Permeable Pave Quick Links • Project Gallery • list of Projects • Eco-Stone Brochur • Eco-Stone Design ' • Specifications • Case Studies • Articles • EPA Information • Municipal Regulatic • Low Impact Develo • LEED • Approvals FAQ... Can permeable pavei snow plowed? ANSWER... Yes. Just as with our traditional pavers, UN Permeable Pavers ca plowed in the winter. In addition, snow and melt and drain throug drainage voids, Iherel minimizing icing haza Have more questions See our FAQs PDF fi learn more. iMuuicm oepamimg oaiiie aox - simtree lecnnologies Page 1 of 1 Home I Products | Contact Us | Engineering | News | About Us Engineering Drawings Nutrient Separating Baffle Box Grate Inlet Skimmer Box Curb Inlet Basket High Capacity Curb Inlet Basket GR8 Protector Reports Nutrient Separating Baffle BOXTM Because the entire flow Is always treated and head loss is so minimal, determining the appropriate size of the Nutrient Separating Baffle BOXTM for a project Is more often an element of pipe size than flow rate. Listed below are common sizes. Custom Sizes are available. *Height can vary as needed so that the top of the vault is either at finish grade or close to finish grade for access and servicing. ** Please contact us to obtain AutoCad drawings for specific sizes/configurations ** Recommended Pipe Sizes; 4" to 12" 8" to 18" 12" to 18" 12" to 30" 18" to 36" 30" to 48" 36" to 54" 42" to 60" 48" to 60" 54" to 72" Model # Inside Inside Width Length Baffle Height Standard Inside Height* NSBB- 2-4-60 2' 4' 24" 5' NSBB- 3-6-72 3' 6' 36" 6' NSBB- 4-8-84 4' 8' 36" 7' NSBB- 5-10-84 5' 10' 36" 7' NSBB- 6-12-84 6' 12' 36" 7' NSBB- 8-12-84 8' 12' 36" 7' NSBB- 8-14-100 8' 14' 40" 8'4" NSBB-10-14- 100 10' 14' 40" 8'4" NSBB-10-16- 125 10' 16' 46" 10'5" NSBB-12-20- 132 12' 20' 48" 11' 798 Clearlake Road Suite 2 Cocoa FL 32922 Ph:(321) 637-7552 Fax: (321) 637-7554 Site Map Login- http.7/ww.suntreetech.com/Engineering/Drawings/Nutrient+Separating+Baffle+^ 9/28/2010 BIO LET^/V ET/xy V/F^Orsy/V^HT/VT^^L Av/,„ ) ED Ell— CD FLOW & e> rMSS SPECIFICATIONS FOR THE BIOMASS SEPARATING SCREEN SYSTEM. SEDIMENT STORAGE, AND SKIMMER SPECIFICATIONS I. Inflow Pipe Area (8" PVC AS DRAWN) 0.55 sq.ft. 4" X 30" BAFFLE- SCREEN SPECIFICATIONS: 2. Open orifice area in screen system - 3. Open orifice area in screen system • with SOX blockage 4. Open orifice area in screen system - with 75X blockage By-pass through screen system - Minimum by—pass around screen system • Screen system storage volume • 4.07 sq.ft. • 2.03 sq.ft. • t.OI sq.ft. • 0.39 sq.ft. • 1.54 sq.ft. 2.73 cu.ft. HINGED BOTTOMS SEDIMENT STORAGE: 8. Volume of first chamber S, Volume of second chambsr W. Volume of third chamber SKIMMER SPECIFICATIONS: 11. Flow area under skimmer 12. Area of pipe in line with skimmer 13. Area of between skimmer and outflow pipe- parallel with the surface of the pipe •5.16 cu.ft. • 5.00 cu.ft. 5.16 cu.ft. 14" X 34" X 16" TALL SCREEN SYSTEM 24" Manhole rings & covers typical. Also available, Hatches with Locks, and risers. OIL SKIMMER TO BE PROVIDED BY BIO CLEAN Zrzpr^ STORM BOOM PATENTED AND PATENTS PENDING 8 PVC TYP GROUT TYP TURBULENCE DEFLECTOR PLAN VIEW INFLOW AND OUTFLOW PIPES ARE TO BE FLUSH WITH THE INSIDE SURFACE OF THE CONCRETE STRUCTURE (CAN NOT INTRUDE BEYOND FLUSH) -2.25 sq.ft. • 0.35 sq.ft. • 1.04 sq.ft. FRONT VIEW OIL SKIMMER TO BE PROVIDED BY BIO CLEAN 013- 08-14 •30- PATUfTED TOP OF BAFFLE NOTES: 6' TO 12' enma BBxms FOR LEVEUNH BACK VIEW 1. CONCRETE 28 DAY COMPRESSIVE STRENGTH fc-S,000 PSI. 2. REINFORCmGiASTU A-615. GRADE 60. 3. SUPPORTS AN H20 LOANNG AS INDICATED BY AASHTO. 4. jaNT SEALANT: BUTYL RUBBER SS-S-00210 5. TOP, BOTTOM, +WALLS ARE 6' THICK. 6. UDS FOR THE TOP OF THE SCREEN SYSTEM ARE AVAILABLE e' TO 12" OawtL FOR UVEUMC LEFT END VIEW PEAK TREATMENT DESIGN FLOW 1 CUBIC FOOT PER SEC. TREATMENT REFERS TO AT LEAST SOX REMOVAL OF TOTAL SUSPENDED PARTICLES FROM 0.12SUM TO 2MM IN SIZE BASED ON A MAXIMUM FLOW RATE OF 6 UNEAR FEET PER SECOND THROUGH PIPE. PEAK DESIGN FLOW 2 CUBIC FEET PER SEC. OIL SKIMMER TO BE PROVIDEO BY BIO CLEAN TOP OF BAFFLE e' TO 12' eRIWB. FOR LEVBMB RIGHT END VIEW £:XCL.US/V£: CAUirOF^NIA DISTRIBUTOR: BIO CLET/A/N/ E:I\I\/IROMME:NTAL SETRV/CE: R.O. BOX 869. OCEVA/S/S/De:, CA. 920-^9 TEL.. -760 —•4-3:5—-76-^0 F^AX:60 — ^JJ — J 1 76 Elm dil: info&tDiocl&anens/ircnmentcil. net SUNTREE TECHf^OLOaiES. INC-79a CLEAFil-AKE RO. SUITE #2 COCO/A. rL. J29Z2 STANDARD MODEL SUNTREE TECHf^OLOaiES. INC-79a CLEAFil-AKE RO. SUITE #2 COCO/A. rL. J29Z2 4-07-21-05-03 NUTRIENT SEPARATING BAFFLE BOX MODEL NO. NSBB—2 —•4.—BO 4-07-21-05-03 NUTRIENT SEPARATING BAFFLE BOX MODEL NO. NSBB—2 —•4.—BO OMTKt DATE: OVyz 1 /OS SCALE: — S7.S DRAP-TER: T.M.Z. UNITS =INCI-IES 'ecnicai Specifications For The Nutrient Separating Baffle Box Model - Stormwater Treatment Svstam 1. The stormwater treatment system shall be capable of inline installation with minimal head loss. Offline installation is not on acceptable oleternotive unless orgmally deisigned by the engineer. Treatment of gross solids must occur at flow rates higher than the specified treatment flow. The stormwater treatment system must provide treatment at all flow rotes. 2. For flows of 74.67 gpm per square foot of settling chamber area a removal efficiency of at least 90X for TSS will be achieved and flows of up to 124.44 gpm per square foot of seelting chamber area will be able to pass through the stormwater treatment system for treatment without causing scouring. This must be proven though full scole testing. J. The stormwater treatment system will be able to store captured solid debris such as leaves ond litter in a dry stote within the nutrient separating screen sysetm between rain events. The volume of dry storage will be equal or greater than that specificed on the drawing. Jiment°'^""^°*^^ 'reofmeni system will have the capacity to store equal to or greater than that specified on the drawing for captured 4 sediment. 5. The stormwater treatment system will hove a skimmer located in front of the outflow opening. The bottom of the skimmer will be located 6 below the static water leveL Adjacent to the influent side of the skimmer is a cage containing many hydrocarbon absorption booms that will float at the top surface of the water in the stonnwater treatment structure. This ensures absorption of hydrocarbons though a wide range of operating flows. 6. The nutrient separating screen system shall be positioned approximately 3.5' above the static water level within the baffle box Adjacent to the inflow, the screen system will hove openings on both sides that have a combined cross sectional area that exceeds the cross sectional area of the pipe. These openings will act as an intemal bypass for water flow in the event that the screen system becomes full of debris. ' 7. The nutrient separating screen system shall have a minimum of 6' of vertical adjustment. The adjustment method shall be a system with brackets that are oHached to the sides of the screen system that will slide vertically along 1 1/2' x 1 1/2' aluminum square poles Iwo stainless steel bolts on each bracket can be tightened to lock the screen system in place, or loosened to allow for vertical adjustment of the screen system. The square poles are anchored to the baffle wall by 1/2' minimum diameter stainless steel bolts. 8. The nutrient separating screen system shall hove a minimum of 3" of horizontal adjustment in the direction of the length of the concrete structure. The brockets that clamp the vertical adjustment poles to the side of the scrven system can be repositioned to allow of horizontal adjustment. 9. The nutrient separating screen system shall have a section adjacent to the inflow which is hinged and can be opened for cleaning This section will function as a screened ramp to direct debris into the main body of the screened system. The sides of this section will be made of stainless steel screen and transition in vertical height from a minimum of 8' tall nearest the inflow to the height of the mom body of the screen system. The lower sides along this inflow section will provide bypass for water flow around the main body of the screen system if necessary. The cross sectional area of the bypass around the screen system will be equal to or exceed the cross actional area of the inflow pipe. l^Z nofne/7< separating screen system shall give access from above grade to the lower sediment collection chambers by the following methoa. Ihe bottom of the screen system will contain hinged screened doors that can be opened in such a way as to altow adequate access for a vacuum truck to remove everything in all ihe lower collection chambers. 11. The nutrient separating screen will be a welded aluminum framework spanned by stainless steel screen, be rectangular in shape and be formed to make a bottom, 2 long sides, and 1 end ; the top and 1 end will remain open. The screen system will consist of panel sections that are held together with stainless steel bolts. When the panel sections are unbolted and separated from each other they must be able to pass through an access hatch or manhole in the top of the baffle box for removal purposes. The aluminum frorne worit. will be made 1 1/2' x 1 1/2' x X" aluminum angle beam. The screen used to span the aluminum frame is described as follows- For the body of the screen system, flattened expanded stainless steel sheet 1/2' No. 16 F: Open area = 60X; Grade = 304 Stainless SteeL The screen will be attached to the screen system frame by sandwiching the screen to the aluminum frame between a series of 1" X 3/16 aluminum bars and welded in place. 12. A turbulence deflector will be attached near the top of each of the baffles with }i" stainless steel through bolts and stainless steel fender washers. The turbulence deflectors will be made from laminated fiberglass and measure a minimum of 1/4' in thickness The turbulence deflectors will form a horizontal ledge that measures 8" from the downstream side of the first baffle and 6' from the downstream side of the second baffle, and span the full width of the baffle box. 13. The stormwater treatment system will be precast concrete. The concrete will be 28 day compressive strength fc = 5,000 psi Steel reinforcing will be ASTM A - 675 Grade 60. Structure will support an H20 loading as indicated by AASHTO. The joint between the concrete sections will ship lap and the joint sealed with Ram-Nek or equal butyl rubber joint sealant. 14. For access into the stormwater treatment system, two to three holes will be cast into the top of the vault. 15 The inflow and outflow pipes will not intrude beyond flush with the inside surface of the Nutrient Separating Baffle Box The space between the pipe holes in the ends of the stormwater treatment system and the outside surface of the pipe will be filled with non-shrink grout to form a water proof seal. 16. The nutrient separating screen system shall extended more than half way of the internal lenght of the stormwater treatment system The nutrient separating screen system shall start at the inflow pipe not more than 4' from the wall of the inflow pipe. 17. The stormwater treatment system must have two separate reports verifying no scouring occurs at flows equal to or greater than the specified treatment flow rote for that particle size distribution. » 18. The stormwater treatment system shall have a shallow sump, not more than 48" from invert of outflow pipe to bottom floor of the sump area. stormwater treatment system must have a miniumium of two sediment chambers (sump areas) which are separated by a vertical wier that divides the chamber from the bottom of the sump to the invert of the outflow pipe. No openings are allowed ot the bottom or coming up vertically along the wier Or any other method that would connect the two chambers together such as orfices LU < T3 3 •*-> (fi >^ Ui O O ii