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HomeMy WebLinkAboutCT 13-05; State Street Townhomes; Tentative Map (CT) (6)STATE STREET TOWNHOMES PRELIMINARY STORM WATER MANAGEMENT PLAN (PRIORITY PROJECT) CARLSBAD, SAN DIEGO COUNTY, CALIFORNIA Prepared For: Intracorp Companies 4041 MacArthur Blvd., Suite 250 Newport Beach, CA 92660 Prepared By: CD NSU LYING A ^g^^BI Company 14725 Alton Pkwy Irvine, CA 92618 Contact Person: Scott P, Gilbert, P.E. February 2014 JN 137092 RECEIVED FEB 0 7 20^ CITY OF CARLSBAD PLANNING DIViSION h:\pdata\137092\admin\reports\swmp\preliminaryswmp_2014-01-31.cloc TABLE OF CONTENTS Section 1: Purpose and Scope 3 Section 2: Project Information 4 2.1 Project Description 5 2.2 Project Activities 6 Section 3: Water Quality Pollutants of Concern 7 3.1 Potential Pollutants 7 3.2 Primary Pollutants of Concern 8 Section 4: Water Quality Conditions of Concern 9 Section 5: Standard Stormwater Requirements 1 5.1 Minimize Impervious Surfaces 1 5.2 Disconnect Impervious Discharges 1 5.3 Conserve Natural Areas 1 5.4 Stenciling Inlets and Signage 1 5.5 Landscape Design 1 5.6 Water Efficient Landscaping 1 5.7 Protect Slopes and Channels 1 5.8 Trash Receptacles 12 5.9 Material Storage Areas 12 Section 6: BMP Design Calculations 13 6.1 BMP Design Sizing 13 6.2 Relative Effectiveness of Project Treatment Facilities 18 Section 7: BMP Maintenance Provisions 19 7.1 Maintenance Responsibility 19 7.2 BMP Maintenance Matrix 19 List of Exhibits Exhibit 1 - Proposed SWMP Exhibit Exhibit 2 - Existing Drainage Exhibit List of Appendices Appendix A: Stormwater Standards Questionaire (E-34) Appendix B: BMP Fact Sheets Appendix C: Proprietary BMP Manufacturer Information Sfafe Sfreef Townhomes - Carlsbad, CA Preliminary SWMP SECTION 1: PURPOSE AND SCOPE The City of Carlsbad's Storm Water Management and Discharge Control Ordinance (Carlsbad Municipal Code Chapter 15,12) requires all development permit applications to complete the storm water standards questionnaire (E-34). The purpose ofthe questionnaire is to determine what type of storm water requirements the project must meet. The proposed Project is considered a significant redevelopment since it represents a redevelopment Project replacing 5,000 SF or more of impervious surface over a site of more than 10,000 SF of impervious surface. Therefore, this project is a Priority Development Project. The associated Stormwater Standards Questionnaire (E-34) is included in Appendix "A", Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 2: PROJECT INFORMATION Project Name State Street Townhomes Application Number(s) TBD Project Address 2539, 2541,2551, 2577, & 2589 State Street, Carlsbad, CA Assessor Parcel Number(s) 155-200-07, 203-054-19,20,21,22 Total Project Area 1.89 AC (gross) /1.86 AC (net) 81,021 Square Feet Proposed Project Description and Land Use High Density Residential (Attached) Redevelopment Project that Creates or Replaces 5,000 square feet of Impervious Surface • Not Applicable ^ Increases or Replaces >50% of Pre-Project Impervious Surface U Increases or Replaces <50% of Pre-Project Impervious Surface Project Disturbed Area 1.86 Acres 81,021 Square Feet Predevelopment Impervious Area 1.7 Acres 74,052 Feet Proposed Impervious Area 1.13 Acres 49,306 Square Feet Proposed Pervious Area 0.73 Acres 31,715 Square Feet Project Hydrologic Unit Watershed ^ Cadsbad 904.00 - Buena Vista Lagoon 904.21 City of Carlsbad Drainage Basin ^A • B • c • D Project Hydrologic Soil Group lElA • B • c • D Number of Discharge Locations 2 Location(s) Required to Implement HMP • Yes 1^ No* Number of HMP Compliance Points 0 Location(s) * Project is tributary to existing City storm drain that outlets into tidally influenced Buena Vista Lagoon Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP 2,1 Project Description The proposed Project site is located along State Street, approximately 650 feet south ofthe intersection of State Street and Carlsbad Blvd/Coast Highway, in the City of Carlsbad, California, and is adjacent to the San Diego Northern Railroad right of way which makes up its western boundary. Today, the site encompasses approximately 1.8 acres of existing commercial/industrial development spread across 6 existing lots; this is proposed to be converted into a residential development with 47 townhomes, and associated drive aisles, parking, and common areas. According to the Carlsbad Drainage Master Plan prepared in July of 2008 this Project is located within "Basin A" which "encompasses all areas in the City that drain into the Pacific Ocean via the Buena Vista Creek and the Buena Vista Lagoon." The existing Project site consists of multiple existing buildings, parking areas, and drive aisles and generally drains from north east to south west at a slope of roughly 2-4% across the site. There is a large 66" City of Carlsbad storm drain that bisects the site; however, there does not appear to be any storm drain connections to the Project site itself, and there are no existing stormwater BMPs on the Property The existing runoff sheet flows off the site into the San Diego Northern Railroad property. Figure 1 - Vicinity Map Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP 2.2 Project Activities This redevelopment Project will result in the demolition of all existing buildings, paving, and utilities currently on the Property, the site will then be re-graded for creation of the proposed 47 townhomes, associated drive aisles, and common areas. In its current condition, the Project site discharges surface runoff in roughly 4 locations. The northern most 2 locations sheet flow across the Property line into the San Diego Northern Railroad Property, whereas the 2 locations to the south discharge into the existing City alley where it ultimately enters a catch basin in the center of the alley cul- de-sac that is connected to a 66" City of Cadsbad storm drain that bisects the property. The existing drainage patterns are shown on Exhibit 1 - Existing Site Drainage. The proposed Project will concentrate these existing discharge points, resulting in only 2 discharge points, both of which will connect to the existing 66" storm drain that bisects the Project site, and ultimately outlets directly into Buena Vista Lagoon, approximately 350 feet downstream of the Project. Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 3: WATER QUALITY POLLUTANTS OF CONCERN 3.1 Potential Pollutants The State Street Townhomes project falls in the "Attached Residential" category as highlighted in Table 3-1. Although many constituents are generally anticipated for projects in this category the proposed project is not expected to generate significant amounts of pollutants, Anticipated Pollutants P Potential Pollutants General Pollutant Categories Project Categories Sediments Nutrients Heavy Metals Organic Compounds Trash and Debris Oxygen-Demanding Substances Oils and Grease Bacteria and Viruses Pesticides Detached Residential • • Atta'ched^Be^eifkl^l k'^K • • p(5) • p(3) p(5) Commercial (>100,000 sf) pd) pd) p(2) p(5) • p(3) p(5) Heavy industry / industrial • • • • Auto Repair Shops y^(4)(5) • • Restaurants • • • Hillside Development (>5,000 sf) Parking Lots pd) pd) pd) pd) Retail Gasoline Outlets • • Streets, Highways, and Freeways pd) • p(5) • (1) A potential pollutant if landscaping exists on-site; (2) A potential pollutant ifthe project includes uncovered parking areas; (3) A potential pollutant if land use involved food or animal waste products; (4) Including petroleum hydrocarbons; (5) Including solvents. Sfafe Street Townhomes - Cadsbad, CA Preliminary SWMP Potential pollutants of concern associated with this project category include: Sediments (since there will be landscaped areas on site); Nutrients (since there will be landscaped areas on site); Organic Compounds (since dog walking is possible, and there are small parking areas); Litter and trash collecting in the drainage systems; Oxygen-demanding substances including biodegradable organic material and chemicals (since there will be landscaped areas on site); Oils, grease, and other hydrocarbons emanating from paved areas on the site; Bacteria and Viruses (since dog walking is possible); Pesticides used to control nuisance landscape growth. 3.2 Primary Pollutants of Concern The project site is located in the 14,437-acre (22.6 square mile) Buena Vista Creek Hydrologic Area (HA 904.2), which is part ofthe Carlsbad Hydrologic Unit (HU 904.00). The most immediate receiving waters for the project site are the Buena Vista Lagoon and the Pacific Ocean. According to the California 2006 303(d) list published by the San Diego Regional Water Quality Control Board (RWQCB Region 9), Buena Vista Lagoon is impaired by bacteria indicators, nutrients and sedimentation. The Pacific Shoreline, located approximately half a mile downstream, is listed as impaired by bacteria indicator. Refer to Table 3-2 for the impairments of the downstream waterbodies. It is highly unlikely that the potential pollutants from the project site would have a significant detrimental effect on the listed impairments downstream, but the impairments should be kept in mind when determining the appropriate program of BMPs. Table 3-2 summarizes the receiving waters and their classification by the RWQCB Region 9. Table 3-2 Summary of Receiving Surface Waters Receiving Water Hydrologic Unit Code Approximate Distance From Site 303(d) Impairment(s) Buena Vista Lagoon 904.21 0 mi Sedimentation, Bactena Indicators, Nutrients Pacific Ocean Shoreline (Buena Vista Creek) 904.21 0.5 mi Bacteria Indicators Receiving waters downstream of the project site are impaired by bacteria indicators, nutrients, and sedimentation as shown in Table 3-2. The proposed project activities are anticipated to produce sediment, nutrients, organic compounds, trash debris, pesticides and oil and grease, as shown in Table 3-1. Therefore, the primary pollutants of concern associated with the project are nutrients, and sediment. The remaining anticipated pollutants are considered secondary pollutants of concern. Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 4: WATER QUALITY CONDITIONS OF CONCERN 11.0 Hydromodification Management Plan (HMP) Applicability Determination Figure 6-1. HMP Applicability Determination Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Node Component Response Response 1 Priority Development Project 13 Yes - Go to Node 2 • No - Exempt 2 Proper Energy Dissipation ^ Yes - Go to Node 3 Intentionally left blank Go to Node 3 3 Increase Impervious Area • Yes - Go to Node 4 IEI No - Go to Node 5 4 Increase Unmitigated Peak Flows to Any Outlet Location • Yes - Go to Node 5 K No - Exempt 5 Direct Discharge to an Exempt System • Yes - Exempt • No - Go to Node 6 6 Direct Discharge to a Tidally Influenced Lagoon Area ^ Yes - Exempt • No - Go to Node 7 7 Direct Discharge to Stabilized Conveyance to Exempt System • Yes - Go to Node 8 • No - Go to Node 9 8 Does Stabilized Conveyance Have Capacity to Convey Ultimate QIO • Yes - Exempt • No - Go to Node 9 g Discharge to Highly Urbanized Area • Yes - Exempt • No-Go to Node 10 10 Urban Infill Project Discharging to Stabilized Conveyance • Yes-Goto Node 11 • No - HMP Controls Required Goto Node 14 11 Determine Domain of Analysis • Yes-Go to Node 12 Intentionally Left Blank Does Not Apply to Node 11 12 Stabilized Conveyance Extends Beyond Domain of Analysis and Eventually Discharges to LOW Susceptibility Stream • Yes-Goto Node 13 • No - HMP Controls Required Go to Node 14 13 Cumulative Future Impacts Represent <3% Impervious Area Increase • Yes - Exempt • No - HMP Controls Required Go to Node 14 14 Go to HMP Figure 6-2 Mitigation Criteria and Implementation Comments: Project Is tributary to an existing City storm drain that discharges directly to Buena Vista Lagoon approximately 350 feet downstream of the Project Site. 10 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 5: STANDARD STORMWATER REQUIREMENTS standard Stormwater Requirements involve incorporating the following applicable techniques into the project design: 5.1 Minimize Impervious Surfaces Using excessive impervious surfaces tend to increase the potential of pollutant contact with urban runoff and increase runoff. The overall project decreases the area of pollutant-generating impervious surfaces versus what exists today. The existing site has no landscaping and is roughly 92% impervious, whereas the proposed site will be approximately 61% impervious. This reduction in imperviousness has been accomplished by creating new landscaped common areas, as well as utilizing permeable pavers in all project drive aisles. 5.2 Disconnect Impervious Discharges The proposed Project Site will utilize a combination of flow-through planters (for buildings) and bio-retention (drive aisles and common areas) to provide water quality treatment, 5.3 Conserve Natural Areas The existing site is fully developed with roughly 92% being impervious. There are no natural areas within the Project site to conserve. However, the proposed Project will significantly increase the amount of pervious surface. 5.4 Stenciling Inlets and Signage All new storm drain grate inlets constructed as part of this project will be signed with the message indicating they drain to the ocean, as directed by the City. The project also proposes signs with descriptive language prohibiting dumping into the Buena Vista Lagoon. 5.5 Landscape Design Efficient landscape design can be an effective source-control to prevent pollution in storm water and dry-weather flows. The proposed site landscaping will comply with this requirement. 5.6 Water Efficient Landscaping Landscape designs that group plants with similar water requirements can reduce excess irrigation runoff and promote surface infiltration. The proposed site landscaping irrigation will comply with this requirement. 5.7 Protect Slopes and Channels The project runoff is self-contained within the Project site, and outlets to storm drain. This configuration will prevent adjacent properties from any effect of storm water runoff 11 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP from this Project Site. 5.8 Trash Receptacles Each unit will have private trash bins to be stored in the garage. These bins will have lids, and only be outside of the garage on trash pickup days. Common areas will have trash receptacles, and will be equipped with lids that prevent contact with rainfall. 5.9 Material Storage Areas No material storage will take place at the proposed project site. 12 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 6: BMP DESIGN CALCULATIONS 6,1 BMP Design Sizing The following tables detail the proposed BMP sizing calculations: Tabulation of Areas Draining to Flow Through Planter DMA-1 Surface Type Area (ft^) Runoff Factor Area x Runoff Factor Roofs 5204 1.0 5204 Concrete/Asphalt 1.0 0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0.2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0,1 0 Turfblock 0,1 0 Amended, Mulched soil 0.1 0 Landscape Areas 52 0.1 5 Subtotal 5209 IMP Sizing Faaor (SUSMP Table 4-6) 0.04 Minimum IMP Area 20S t Praposed IMP Area (Water Quality Tr^Gne Bioretention Configuration PLANTER Total Area of DMA 5256 13 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Tabulation of Areas Draining to Flow Through Planter DMA-2 Surface Type Area (ft^) Runoff Factor Area x Runoff Factor Roofs 5907 1.0 5907 Concrete/Asphalt 1.0 0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0.2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 316 0.1 32 Subtotal 5939 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 238 •Vf i^'Propt^s"^ IMP Area (Water QualitifWto^^^^^ Bioretention Configuration PLANTER Total Area of DMA 6223 Tabulation of Areas Draining to a Katchall DMA-3 Surface Type Area (ft^) Runoff Factor Area x Runoff Factor Roofs 6275 1.0 6275 Concrete/Asphalt 1.0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0.2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 156 0.1 16 Subtotal 6291 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 252 f ' Proposed IMP Area (Water Quality Treatment Only) Bioretention Configuration PLANTER Total Area of DMA 6432 14 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Tabulation of Areas Draiiiilgto a Bioretention IMP Surface Type Area (ft') Runoff Factor Area x Runoff Factor Roofs 5385 1.0 5385 Concrete/Asphalt 1.0 0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0.2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 156 0.1 16 Subtotal 5401 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 216 Propbsed IMP Area (Water Quality Trieatmieht Only) Bioretention Configuration PLANTER Total Area of DMA 5541 Tabulation of Areas Draining to a Bioretention IMP DMA-5 Surface Type Area (ft') Runoff Area x Runoff Surface Type Area (ft') Factor Factor Roofs 4517 1.0 4517 Concrete/Asphalt 1.0 0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0.2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0,1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 21 0.1 2 Subtotal 4519 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 181 Proposed IMP Area (Water Quality Treatment Only) 230 Bioretention Configuration PLANTER Total Area of DMA 4538 15 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Tabulation of Areas Draining to Flow Through Planter DMA-6 Surface Type Area (ft') Runoff Factor Area x Runoff Factor Roofs 3918 1.0 3918 Concrete/Asphalt 1102 1.0 1102 Grouted unit Pavers 1.0 0 Solid Unit Pavers 3629 0.2 726 Pervious concrete 0,1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 1248 0,1 125 Subtotal 5870 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 235 f i'--^'^^ Proposed IMP Area'(WaterQuality treV Only)'' Bioretention Configuration KATCHALL Total Area of DMA 9897 Tabulation of Areas Draining to Flow Through Planter DMA-7 Surface Type Area (ft') Runoff Factor Area x Runoff Factor Roofs 11595 1.0 11595 Concrete/Asphalt 1.0 0 Grouted unit Pavers 1.0 0 Solid Unit Pavers 7715 0.2 1543 Pervious concrete 1735 0.1 174 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 2007 0.1 201 Subtotal 13512 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 540 iiK- V^j PropbsedlMP Area (Water Qiiafity treatment Only) • r .540 Bioretention Configuration BMPSPEC* Total Area of DMA 23052 * See Permeable Paver Details in Appendix C 16 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Tabulation of Areas Draining to Flow Through Planter DMA-8 Surface Type Area (ft') Runoff Factor Area x Runoff Factor Roofs 2832 1.0 2832 Concrete/Asphalt 1843 1.0 1843 Grouted unit Pavers 1.0 0 Solid Unit Pavers 5651 0.2 1130 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 5069 0.1 507 Subtotal 6312 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 252 Prd^TMPAr^(WaterQ;ialiWfiS Bioretention Configuration BMP Total Area of DMA 15395 Tabulation of Areas Draining to a Bioretention IMP DMA-9 Surface Type Runoff Area x Runoff Surface Type Area (ft') Factor Factor Roofs 0 1.0 0 Concrete/Asphalt 728 1,0 728 Grouted unit Pavers 1.0 0 Solid Unit Pavers 0,2 0 Pervious concrete 0.1 0 Porous Asphalt 0.1 0 Crushed Aggregate 0.1 0 Turfblock 0.1 0 Amended, Mulched soil 0.1 0 Landscape Areas 1694 0.1 169 Subtotal 897 IMP Sizing Factor (SUSMP Table 4-6) 0.04 Minimum IMP Area 36 r Projposed IMP Area (Water Quality Treatment Only) 50 Bioretention Configuration BASIN Total Area of DMA 2422 17 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP 6.2 Relative Effectiveness of Project Treatment Facilities Hies and IMFSflilHi Pollutants Grouped by Method of Transport Treatment Facility/IMP Coarse Sediment and Trash Pollutants Associated with Fine Particles During Transport Pollutants that tend to be Dissolved Following Treatment IE Bioretention IMP High High Medium ^ Flow Through Planter IMP High High Medium • Infiltration IMP High High High n Conventional Vegetated Swale High Medium Low • Extended (Dry) Detention Basins High High Low • Media (Sand) Filter High High Low • Wet Pond High High Medium O Constructed Wetland High High Medium M Proprietary Vault/Tree Well High Medium Low O Proprietary Inlet Filter High Low Low 18 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP SECTION 7: BMP MAINTENANCE PROVISIONS 7.1 Maintenance Responsibility On-site BMPs, and storm drain related facilities are assumed to be private, and therefore would be maintained by the Homeowners Association or Property Manager. This includes: • Landscape Maintenance • BMP Maintenance • Common Area Litter Pickup • Storm Drain/Catch Basin Maintenance 7.2 BMP Maintenance Matrix Routine Maintenance Activities for Bioretention Areas No. Maintenance Task Frequency of Task 1 Remove obstructions, debris and trash from bioretention area and dispose of properly. Monthly, or as needed after storm events 2 Inspect bioretention area to ensure that it drains between storms and within five days after rainfall. Monthly, or as needed after storm events 3 Inspect inlets for channels, soil exposure or other evidence of erosion. Clear obstructions and remove sediment. Monthly, or as needed after storm events 4 Remove and replace all dead and diseased vegetation. Twice a year 5 Maintain vegetation and the irrigation system. Prune and weed to keep bioretention area neat and orderly in appearance. Before wet season begins, or as needed Routine Maintenance Activities for Flow-Through Planters No. Maintenance Task Frequency of Task 1 Evaluate health of trees and groundcover. Remove and replace all dead and diseased vegetation. Treat vegetation using preventative and low-toxic methods. Twice a year 2 Maintain vegetation and the irrigation system. Prune and weed to keep flow-through planter neat and orderly in appearance. As needed 3 Check that mulch is at appropriate depth (3 inches per soil specifications) and replenish as necessary. Monthly 4 Check that soil is at appropriate depth. Till or replace soil as necessary to maintain a minimum of 6 inches between top of mulch and overflow weir. Before wet season and as necessary 5 Remove accumulated sediment, litter and debris from flow-through planter and dispose of properly. Confirm that no clogging will occur and that the box will drain within three to four hours. Before wet season and as necessary 6 Inspect flow-through planter to ensure that there are no clogs. Test with garden hose to confirm that the planter will drain within three to four hours. Monthly during the wet season, and as needed after storm events 19 Sfafe Sfreef Townhomes - Cadsbad, CA Preliminary SWMP Routine Maintenance Activities for Bioretention Areas 7 Inspect downspouts from rooftops and sheet flow from paved areas to ensure flow to planter box is unimpeded. Remove debris and repair damaged pipes. Check splash blocks or rocks and repair, replace and replenish as necessary. Monthly during the wet season, and as needed after storm events 8 Inspect overflow pipe to ensure that it will safely convey excess flows to storm drain. Repair or replace any damaged or disconnected piping. Before the wet season, and as necessary 9 Inspect flow-through planter to ensure that box is structurally sound (no cracks or leaks). Repair as necessary. Annually 10 Inspect flow-through planter using the attached inspection checklist Monthly, or after large storm events, and after removal of accumulated debris or material Routine Maintenance Activities for Tree Well Filters (Katchall) No. Maintenance Task Frequency of Task 1 Evaluate health oftrees and groundcover. Remove and replace all dead and diseased vegetation. Treat vegetation using preventative and low-toxic methods. Twice a year 2 Maintain vegetation and the irrigation system. Prune and weed to keep tree well filter neat and orderly in appearance. As needed 3 Check that planting mix is at appropriate depth and replenish as necessary. Before wet season and as necessary 4 Check that mulch is at appropriate depth (3 inches per soil specifications) and replenish as necessary. Monthly 5 Remove sediment, litter and debris from tree well filter. Confirm that no clogging will occur and that the filter will drain per the design specifications. Dispose of sediment, litter and debris properly. Before wet season and as necessary 6 Inspect Tree Well Filter to ensure that it drains between storms and within five days after rainfall. Periodically or as needed after storm events 7 Inspect overfiow pipe to ensure that it will safely convey excess flows to storm drain. Repair or replace any damaged or disconnected piping. As necessary 8 Inspect tree well filter using the attached inspection checklist. Monthly, or after large storm events, and after removal of accumulated debris or material 20 V STATE STREET (PUBL IC "STRErr")" •BMP #9 LEGEND LANDSCAPE AREA BIORETENTION AREA FLOW THROUGH PLANTERS m KATCHALL I I PERMEABLE PAVERS _SD—SD- PROPOSED STORM DRAIN DMA BOUNDARIES DIRECTION OF FLOW EXHIBIT 1 STATE STREET TOWNHOMES BMP EXHIBIT SCALE: 1"=40' CQNSULTINB A ^^^^Hcompany January 31, 2014 STATE STREET EXHIBIT 2 STATE STREET TOWNHOMES EXISTING DRAINAGE E OO < a: Q o z F SCALE: r=40' • ONSULTI NB November 13, 2013 APPENDIX "A" Stornn Water Standards Questionnaire (E-34) STORM WATER Development Services Land Development Engineering STANDARDS Development Services Land Development Engineering CITY OF QUESTIONNAIRE E-34 1635 Faraday Avenue 760-602-2750 CARLSBAD QUESTIONNAIRE E-34 www,carlsbadca.gov To address post-development pollutants that may be generated from development projects, the City requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMP's) into the project design per the City's Standard Urban Stormwater Management Plan (SUSMP). To view the SUSMP, refer to the Engineering Standards (Volume 4, Chapter 2) at www.carlsbadca.qov/standards. Initially this questionnaire must be completed by the applicant in advance of submitting for a development application (subdivision, discrefionary permits and/or construction permits). The results of the questionnaire determine the level of storm water standards that must be applied to a proposed development or redevelopment project. Depending on the outcome, your project will either be subject to 'Standard Stormwater Requirements' or be subject to additional criteria called 'Priority Development Project Requirements'. Many aspects of project site design are dependent upon the storm water standards applied to a project. Your responses to the questionnaire represent an initial assessment of the proposed project condifions and impacts. City staff has responsibility for making the final assessment after submission of the development applicafion. If staff detennines that the quesfionnaire was incorrectly filled out and is subject to more stringent stonn water standards than inifially assessed by you, this will result in the return of the development application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the City. If you are unsure about the meaning of a quesfion or need help in detennining how to respond to one or more of the quesfions, please seek assistance from Land Development Engineering staff. A separate completed and signed questionnaire must be submitted for each new development application submission. Only one completed and signed quesfionnaire is required when multiple development applicafions forthe same project are submitted concurrenfiy. In addifion to this quesfionnaire, you must also complete, sign and submit a Project Threat Assessment Form with construcfion permits for the project. Please start by completing Step 1 and follow the instructions. When completed, sign the form at the end and submit this with your application to the city. ^ -TO BE COMPLETED FOR Al To determine if your project is a priority development project, please answer the following questions: YES NO 1. Is your project LIMITED TO constructing new or retrofitting paved sidewalks, bicycle lanes or trails that meet the following criteria: (1) Designed and constructed to direct storm water runoff to adjacent vegetated areas, or other non-erodible permeable areas; OR (2) designed and constructed to be hydraulically disconnected from paved streets or roads; OR (3) designed and constructed with permeable pavements or surfaces in accordance with USEPA Green Streets guidance? X 2. Is your project LIMITED TO retrofitting or redeveloping exisfing paved alleys, streets, or roads that are designed and constructed in accordance with the USEPA Green Streets guidance? X If you answered "yes" to one or more of the above questions, then your project is NOT a priority development project and therefore is NOT subject to the storm water criteria required for priority development projects. Go to step 4, mark the last box stating "my project does not meet PDP requirements" and complete applicant information. If you answered "no" to both quesfions, then go to Step 2. E-34 Page 1 of 3 Effective 6/27/13 STORM WATER Development Services Land Development Engineering STANDARDS Development Services Land Development Engineering ^ CITY OF QUESTIONNAIRE E-34 1635 Faraday Avenue 760-602-2750 CARLSBAD QUESTIONNAIRE E-34 www.carlsbadca.gov Wm ^1 To determine if your project is a priority development project, please answer the following quesfions: YES NO 1. Is your project a new development that creates 10,000 square feet or more of impervious surfaces collecfively over the entire project site? This includes commercial, industrial, residential, mixed-use, and public development projects on public orpnvate land. 2. Is your project creafing or replacing 5,000 square feet or more of impervious surface collectively over the enfire project site on an existing site of 10,000 square feet or more of impervious surface? This Includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. X 3. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collecfively over the entire project site and supports a restaurant? A restaurant is a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption. 4. is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collectively over the enfire project site and supports a hillside development project? A hillside development project includes development on any natural slope that is twenty-five percent or greater 5. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collecfively over the entire project site and supports a parking lot. A parking lot is a land area or facility for the temporary pari<ing or storage of motor vehicles used personally for business or for commerce. 6. Is your project a new or redevelopment project that creates 5,000 square feet or more of impervious surface collecfively over the enfire project site and supports a street, road, highway freeway or driveway? A street, road, highway, freeway or driveway is any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. 7. Is your project a new or redevelopment project that creates or replaces 2,500 square feet or more of impervious surface collectively over the enfire site, and discharges directly to an Environmentally Sensifive Area (ESA)? "Discharging Directly to" includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingles with flows from adjacent lands).* 8. Is your project a new development that supports an automotive repair shop? An automotive repair shop is a facility that is categorized in any one of the following Standard Industrial C/ass/ffcaf/on (SIC) codes: 5013, 5014, 5541, 7532-7534, or 7536-7539. 9. Is your project a new development that supports a retail gasoline outlet (RGO)? This category includes RGO's that meet the following criteria: (a) 5,000 square feet or more or (b) a project Average Daily Traffic (ADT) of 100 or more vehicles per day. 10. Is your project a new or redevelopment project that results in the disturbance of one or more acres of land and are expected to generate pollutants post construction? Ills your project located within 200 feet of the Pacific Ocean and (1) creates 2,500 square feet or more of impervious surface or (2) increases impervious surface on the property by more than 10%? If you answered "yes" to one or more of the above questions, you ARE a priority development project and are therefore subject to implemenfing structural Best Management Practices (BMP's) in addifion to implemenfing Standard Storm Water Requirements such as source control and low impact development BMP's. A Storm Water Management Plan (SWMP) must be submitted with your applicafion(s) for development. Go to step 3 for redevelopment projects. For new projects, go to step 4 at the end of this questionnaire, check the "my project meets PDP requirements" box and complete applicant information. If you answered "no" to all of the above quesfions, you ARE NOT a priority development project and are therefore subject to implemenfing only Standard Storm Water Requirements such as source control and low impact development BMP's required for all development projects. A Stonn Water Management Plan (SWMP) is not required with your application(s) for development. Go to step 4 at the end of this questionnaire, check the "my project does not meet PDP requirements" box and complete applicant information. E-34 Page 2 of 3 Effective 6/27/13 ^ CITY CARLSBAD O F STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Land Development Engineering 1635 FaradayAvenue 760-602-2750 www.carlsbadca.gov •V-.f: TO BE COM' OPMENT PROJECTS IHAT ARE PRIORTTY DE Complete the quesfions below regarding your redevelopment project: YES NO Does the redevelopment project result in the creation or replacement of impervious surface in an amount of less than 50% ofthe surface area ofthe previously exisfing development? X Ifyou answered "yes," the structural BMP's required for Priority Development Projects apply only to the creafion or replacement of impervious surface and not the enfire development Go to step 4, check the "my project meets PDP requirements" box and complete applicant Information. If you answered "no," the structural BMP's required for Priority Development Projects apply to the enfire development. Go to step 4, check the "my project meets PDP requirements" box and complete applicant information. APPROPRIATE S>i E) My project meets PRIORITY DEVELOPMENT PROJECT (PDP) requirements and must comply with addifional stonnwater criteria per the SUSMP and I understand I must prepare a Storm Water Management Plan for submittal at fime of applicafion. I understand flow control (hydromodification) requirements may apply to my project. Refer to SUSMP for details. • My project does not meet PDP requirements and must only comply with STANDARD STORMWATER REQUIREMENTS per the SUSMP. As part ofthese requirements, I will incorporate low impact development strategies throughout my project. Applicant Informafion and Signature Box Intracorp Companies Address: 4041 MacArthur Blvd., Suite 250 Accessor's Parcel Number(s): 203-054-19,20,21,22,155-200-07 Applicant Name: Ken Benson Applicant Title: VP of Project Management Applicant Signature: Date: This Box for City Use Only City Concurrence: YES NO By: Date: Project ID: * Environmentally Sensifive Areas include but are not limited to all Clean Water Act Secfion 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their quivalent under the Multi Species Conservafion Program within the Cifies and County of San Diego; and any other equivalent environmentally sensifive areas which have been idenfified by the Copennittees. E-34 Page 3 of 3 Effective 6/27/13 APPENDIX "B" BMP Fact Sheets SECTION 4: LID DESIGN GUIDE Bioretention Facilities I pOTfarahid I . UwsEnglbcflDrtodelennne minimuin craa Bioretention facility configuied for treatment-only requirements. Bioretention facilities can rectangular, linear, or nearly any shape. Bioretention detains runoff in a surface reservoir, filters it through plant roots and a biologically active soil mix, and then infiltrates it into the ground. Where native soils are less permeable, an underdrain conveys treated runoff to storm drain or surface drainage. Bioretention facilities can be configured in nearly any shape. When configured as linear swales, they can convey high flows while percolating and treating lower flows. Bioretention facilities can be configured as in-ground or above- ground planter boxes, with the bottom open to allow infiltration to native soils underneath. If infiltration cannot be allowed, use the sizing factors and criteria for the Flow-Through Planter. • CRITERIA For development projects subject only to runoff treatment requirements, the following criteria apply: Best Uses • Commercial areas • Residential subdivisions • Industrial developments • Roadways • Parking lots • Fit in setbacks, medians, and other landscaped areas Advantages • Can be any shape • Low maintenance • Can be landscaped Limitations • Require 4% of tributary impervious square footage • T3^ically requires 3-4 feet of head • Irrigation typically required Parameter Soil mix depth Soil mix minimum percolation rate Soil mix surface area Criterion 18 inches minimum 5 inches per hour minimum sustained (10 inches per hour initial rate recommended) 0.04 times tributary impervious area (or equivalent) 85 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Parameter Surface reservoir depth Underdrain Criterion 6 inches minimum; may be sloped to 4 inches where adjoining walkways. Required in Group "C" and "D" soils. Perforated pipe embedded in gravel ("Class 2 permeable" recommended), connected to storm drain or other accepted discharge point. • DETAILS Plan. On the surface, a bioretention facility should be one level, shallow basin—or a series of basins. As runoff enters each basin, it should flood and fiU throughout before runoff overflows to the outiet or to the next downstream basin. This will help prevent movement of surface mulch and soil mix. Use check dams for linear bioretention facilities (swales) on a slope. In a linear swale, check dams should be placed so that the lip of each dam is at least as high as the toe of the next upstream dam, A similar principle applies to bioretention facilities built as terraced roadway shoulders. Inlets. Paved areas draining to the facility should be graded, and inlets should be placed, so that runoff remains as sheet flow or as dispersed as possible. Curb cuts should be wide (12" is recommended) to avoid clogging with leaves or debris. AUow for a minimum reveal of 4"-6" between the inlet and soU mix elevations to ensure turf or mulch buildup does not block the inlet. In addition, place an apron of stone or concrete, a foot square or larger, inside each inlet to prevent vegetation from growing up and blocking the inlet. 86 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Recommended design details for bioretention facility inlets (see text). Where runoff is coUected in pipes or gutters and conveyed to the faciUty, protect the landscaping from high-velocity flows with energy-dissipating rocks. In larger instaUations, provide cobble- Uned channels to better distribute flows throughout the faciUty. Upturned pipe outiets can be used to dissipate energy when runoff is piped from roofs and upgradient paved areas. Soil mix. The required soil mix is similar to a loamy sand. It must maintain a minimum percolation rate of 5" per hour throughout the Hfe of the faciUty, and it must be suitable for maintaining plant Ufe. TypicaUy, on-site soUs wUl not be suitable due to clay content. Storage and drainage layer. "Class 2 permeable," Caltrans specification 68-1.025, is recommended. Open-graded crushed rock, washed, may be used, but requires 4"-6" washed pea gravel be substituted at the top of the crushed rock gravel layers. Do not use filter fabric to separate the soU mix from the gravel drainage layer or the gravel drainage layer from the native soU. 87 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Underdrains. No underdrain is required where native soUs beneath the facility are Hydrologic SoU Group A or B. For treatment-only faciUties where native soUs are Group C or D, a perforated pipe must be bedded in the gravel layer and must terminate at a storm drain or other approved discharge point. Outlets. In treatment-only faciUties, oudets must be set high enough to ensure the surface reservoir fiUs and the entire surface area of soU mix is flooded before the outiet elevation is reached. In swales, this can be achieved with appropriately placed check dams. The oudet should be designed to exclude floating mulch and debris. Vaults, utility boxes and light standards. It is best to locate utiUties outside the bioretention facUity—^in adjacent walkways or in a separate area set aside for this purpose. If utility structures are to be placed within the faciUty, the locations should be anticipated and adjustments made to ensure the minimum bioretention surface area and volumes are achieved. Leaving the final locations to each individual utiUty can produce a haphazard, unaesthetic appearance and make the bioretention facility more difficult to maintain. Emergency overflow. The site grading (construction) plan shaU include detaUs that demonstrate the bioretention basin can handle larger (up to 1 OO-year) storm events and address potential clogging of the overflow and route emergency overflows safely. Trees. Bioretention areas can accommodate smaU or large trees. There is no need to subtract the area taken up by roots from the effective area of the facility. Extensive tree roots maintain soU permeabiUty and help retain runoff. Normal maintenance of a bioretention facUity should not affect tree Ufespan. The bioretention faciUty can be integrated with a tree pit of the required depth and fUled with structural soU. If a root barrier is used, it can be located to aUow tree roots to spread throughout the bioretention facility whUe protecting adjacent pavement. Locations and planting elevations should be selected to avoid blocking the faciUty's inlets and outiets. ROOT BARRIER 3^- STRUCTURAL y SOIL Bioretention faciJity configured as a tree weL The root barrier is optional 88 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE • APPLICATIONS Multi-purpose landscaped areas. Bioretention faciUties are easUy adapted to serve multiple purposes. The loamy sand soU mix wiU support turf or a plant palette suitable to the location and a weU-drained soU. Example landscape treatments: • Lawn with sloped transition to adjacent landscaping. • Swale in setback area • Swale in parking median • Lawn with hardscaped edge treatment • Decorative garden with formal or informal plantings • Traffic island with low-maintenance landscaping • Raised planter with seating • Bioretention on a terraced slope Bioretention fadlit)' configured as a recessed decorati^'e lawn with hardscaped edge. Bioretention facility configured and planted as a lawn/ play area. 89 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Residential subdivisions. Some subdivisions are designed to drain roofs and driveways to the streets (in the conventional manner) and then drain the streets to bioretention areas, with one bioretention area for each 1 to 6 lots, depending on subdivision layout and topography. Bioretention areas may be placed on separate, jointiy-owned parcel(s). Bioretention facility receix-ing drainage from indi\idual lots and the street in a residential subdivision. Sloped sites. Bioretention facilities must be constructed as a basin, or series of basins, with the circumference of each basin set level. It may be necessary to add curbs or low retaining waUs. RUNOFF TO PiANTtD «»• nwHi CnrCDFUM OUTLET- Bioretention facilit}' configured as a parking mediaa Note use of tx)lJards in place of curbs, eliminating the need for curb cuts. 90 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Design Checklist for Bioretention • Volume or depth of surface reservoir meets or exceeds rtUnimum. • 18" depth "loamy sand" soil mix with minimum long-term percolation rate of 5"/hour. • Area of soU mix meets or exceeds minimum. • Perforated pipe underdrain bedded in "Class 2 perm" with connection and sufficient head to storm drain or discharge point (except in "A" or "B" soUs). n No fUter fabric. • Underdrain has a clean-out port consisting of a vertical, rigid, non-perforated PVC pipe, with a minimum diameter of 6 inches and a watertight cap. • Location and footprint of facility are shown on site plan and landscaping plan. • Bioretention area is designed as a basin (level edges) or a series of basins, and grading plan is consistent with these elevations. If facility is designed as a swale, check dams are set so the Up of each dam is at least as high as the toe of the next upstream dam. • Inlets are 12" wide, have 4"-6" reveal and an apron or other provision to prevent blockage when vegetation grows in, and energy dissipation as needed. • Overflow connected to a downstream storm drain or approved discharge point. • Emergency spiUage wiU be safely conveyed overland. • Plantings are suitable to the climate and a weU-drained soU. • Irrigation system with connection to water supply. • Vaults, UtiUty boxes, and Ught standards are located outside the minimum soU mix surface area. • When excavating, avoid smearing of the soUs on bottom and side slopes. Minimize compaction of native soUs and "rip" soUs if clayey and/or compacted. Protect the area from construction site runoff 91 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE FOREBAY/CLEWOUr HEAMfAU. EMERGENCY SPiaWAY TOP OF BASIN PLAN VIEW NOT TO SCALE TOP OF BASIN EHERGENCY SPILLWAY- FOREBAY/CLEANOUT ^OUTFLOW "'ifel CLASS 2 PERM. PERFORAIED PIPE (UNDERDRAIN] V2 STORAGE ^18" SPECIFIED (NOTE 2) PLANTING MIX e A>, SECTION NOT TO SOU NOTE SURFACE AREA LIMfT DETERMINED BY EXTENT OF SPECIFIED PLANTING MIX, WHICH IS GOVERNED BY THE OUTLH SPILL ELEVATION. FOR REOUIRED SURFACE AREA REFER TO THE FACTORS AMD EQUATIONS IN THE STORMWATER Ci GUIDEBOOK. Vi STORAGE ACCOMPLISHED WITH INFILTRATION ARCHES, PERFORATED PIPES, CLASS 2 PERM OR OTHER AT THE DESIGNERS DISCREnON. Bioretention Facility 92 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE FLANGE ll ORinCE PLATE CONNECTION (SEE NOTE 1) CLOSED MESH ORATE (GEN. NOTES 4 THRU 7) PLAN CATCH BASIN SPECIRED SOIL MIX \ 2, -CLOSED MESH GRATE (GEN. NOTES 4 THRU 7) ORIRCE PLATE: MIN SOUARE DIMENSIONS 1.0 FT GREATER THAN PIPE DIA HOT-DIP GALVANIZED PLATE AFTER HOLES HAVE BEEN DRILLED r-UIN 6- (TYP) • (TYP) NOTE ORinCE PUTE & FLANGE CONNECTION TO CONCRETE SHALL BE FITTED WITH 30 DUROMETER NEOPRENE RING. iRinCE DIAMETER (DW) SIZED PER DESIGN CRIIERUk |T)IA HOLE (TYP) FLOW CXJNTROL ORIFICE PLATE Bioretention Facility Outlet Detail - A 93 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE 'low-through Plariter Portland 2(J(V4 Stonnwater Manual Best Uses • Management of roof runoff • Next to buUcUngs • Dense urban areas • Where infiltration is not desired Advantages • Can be used next to structures • Versatile • Can be any shape • Low maintenance Flow-through planters treat and detain runoff without aUowing seepage into the underlying soU. They can be used next to buUdings and on slopes where stabiUty might be affected by adding soU moisture. Flow-through planters typicaUy receive runoff via downspouts leading from the roofs of adjacent buUdings. However, they can also be set in- ground and receive sheet flow from adjacent paved areas. PoUutants are removed as runoff passes through the soU layer and is coUected in an underlying layer of gravel or drain rock. A perforated-pipe underdrain is t)fpicaUy connected to a storm drain or other discharge point. An overflow inlet conveys flows which exceed the capacity of the planter. CRITERIA Treatment only. For development projects subject only to runoff treatment requirements, the foUowing criteria apply: Limitations • Can be used for flow-control only on sites with "C" and "D" soUs • Requires underdrain • Requires 3-4 feet of head Parameter Soil mix depth Soil mix minimum percolation rate Criterion 18 inches minimum 5 inches per hour minimum sustained (10 inches per hour initial rate recommended) 94 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Parameter Criterion Soil mix surface area 0.04 times tributary impervious area (or equivalent) Surface reservoir depth 6" minimum; may be sloped to 4" where adjoining walkways. Underdrain TypicaUy used. Perforated pipe embedded in gravel ("Class 2 permeable" recommended), connected to storm drain or other accepted discharge point. • DETAILS Configuration. The planter must be level. To avoid standing water in the subsurface layer, set the perforated pipe underdrain and orifice as nearly flush with the planter bottom as possible. inlets. Protect plantings from high-velocity flows by adding rocks or other energy-dissipating structures at downspouts and other inlets. Soil mix. The required soU mix is simUar to a loamy sand. It must maintain a mirumum percolation rate of 5" per hour throughout the Ufe of the faciUty, and it must be suitable for maintaining plant Ufe. TypicaUy, on-site soUs wUl not be suitable due to clay content. Gravel storage and drainage layer. "Class 2 permeable," Caltrans specification 68-1.025, is recommended. Open-graded crushed rock, washed, may be used, but requires 4"-6" of washed pea gravel be substituted at the top of the crushed rock layer. Do not use filter fabric to separate the soU mix from the gravel drainage layer. Emergency overflow. The planter design and instaUation should anticipate extreme events and potential clogging of the overflow and route emergency overflows safely. • APPLICATIONS Adjacent to buildings. Flow-through planters may be located adjacent to buUdings, where the planter vegetation can soften the visual effect of the buUding waU. A setback with a raised planter box may be appropriate even in some neo-traditional pedestrian-oriented urban streetscapes. At plaza level. Flow-through planters have been successfuUy incorporated into podium-style developments, with the planters placed on the plaza level and receiving runoff from the tower roofs above. Runoff from the plaza level is typicaUy managed separately by additional flow- through planters or bioretention faciUties located at street level. Steep slopes. Flow-through planters provide a means to detain and treat mnoff on slopes that cannot accept infiltration from a bioretention faciUty. The planter can be buUt into the slope simUar to a retaining waU. The design should consider the need to access the planter for periodic 95 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE maintenance. Flows from the planter underdrain and overflow must be directed in accordance with local requirements. It is sometimes possible to disperse these flows to the downgradient hillside. Flow-through planter on the plaza level of a podium-style development Flow-through planter built into a hillside. Flows from the underdrain and overflow must be directed in accoidance with liKal requirements. 96 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE Design Checklist for Flow-through Planter • Reservoir depth is 4-6" minimum. • 18" depth "loamy sand" soU mix with minimum long-term infiltration rate of 5"/hour. • Area of soU mix meets or exceeds minimum. • "Class 2 perm" drainage layer, n No fdter fabric. • Perforated pipe underdrain with outiet located flush or nearly flush with planter bottom. Connection with sufficient head to storm drain or discharge point. • Underdrain has a clean-out port consisting of a vertical, rigid, non-perforated PVC pipe, with a minimum cUameter of 6 inches and a watertight cap. • Overflow connected to a downstream storm drain or approved discharge point. • Location and footprint of facility are shown on site plan and landscaping plan. • Planter is set level, • Emergency spillage wUl be safely conveyed overland. • Plantings are suitable to the climate and a weU-drained soU. • Irrigation system with connection to water supply. 97 City of Carlsbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE EMERGENCY 0VERFU3W GRATE (SEE FLOW-THROUGH PLANTER OUTLET DEIAl) ENERGY DISSIPATION DOWNSPOUT/INLET DISCHARGE TO AN APPROVED LOCATION CONCRETE OR OTHER STRUCTURAL PLANTER WALL WITH Y«ATERPROOFING PLAN LOCKED, REMOVABLE CLOSE-MESH GRATE, SLOPED INSTALLATION PLANTER OUTLET (SEE FLOW-THROUGH PLANTEP OUTLET DETAIL) DISCHARGE TO AN APPROVED LOCATION ONE-WAY CONNECTIONS NOTES: PERFORATED PIPE- (UNDERCRAIN) MIN SL0PE»a5X SECTION ORinCE DRILLED INTO VAULT WALL FORM A 1.5' GROOVE IN CONCRETE AND PROVIDE A CONTINUOUS WATERTIGKT CONNECTION, USING AN APPROVEO SEALANT FLOW-THROUGH PLANTER SHAU. BE SIZED TO MEET CCCWP CRITERIA FOR TREATMENT AND/OR aOW CONIROL. MINIMUM SURFACE AREA OF PLANTER IS 4X OF TWBUTARY IMPERVIOUS AREA FOR TREATMENT ONLY DESIGN. FDR aOW CONIROL AND TREATMENT, REFER TO CCCWP SIZING TOOL CRITERIA SHAPE OF PLANTER CAN VARY TO MEET PROJECT DESIGN REQUIREMENTS AND LOCATION. CLASS 2 PERMEABLE MATERIAL DOWNSPOUTS/INLET PIPES REQUIRE ENERGY DISSIfvmON. USE COUNIY APPROVED ADDITIVE MIXTURE FOR WATERPROOnNG CONCRETE. PLANTINGS: SEE CCCWP RECOMMENDED PLANT UST AND GUIDELINES. PLANTER DESIGN MAY REOUIRE STRUCTURAL ENGINEERING DESIGN. AREA = W « L (ABOVE). EXCLUDES AREA OF VAULT Flow-Through Planter Detail 98 City of Carisbad SUSMP— January 14, 2011 SECTION 4: LID DESIGN GUIDE STEEL VAULT FRAME (NOTE 1 ORCULAR ORIFICE DRILLED INTO GALVANIZED SIEEL VAULT 'LANIER BOX WALL CLOSED MESH GRATE (GEN. NOTES 2 THRU 5) VAULT-PLANTER BOX CONNECTION PLAN HOT-DIP GALVANIZE ENTIRE FRAME ASSEMBLY AFTER FABRICATION AND AFTER HOLES HAVE BEEN DRILLED. 2. FOR WATERHGHT'CONNECTION, INSTALL J" TD 1' THICK X 2" WIDE CONTINUOUS 30 DUROMETER NEOPRENE CASKET, AU AROUND VAULT FTWNE. LOCKED, REMOVABLE CLOSE-MESH GRATE. SLOPED INSTALUTION DISCHARGE . TO AN I=C> APPROVED ' LOCATION ORIRCE DRILLED INTO VAULT WALL SECTION N.T.S. GENERAL OUTLET DETAIL NOTES: 1. OUTFALL PIPE SHALL BE SIZED TO CONVEY DESIGN STORM PER CCCWP DESIGN CRITERIA 2. CRATE SHAa BE MOUNTED USING STAINLESS STEEL HARDWARE AND PROVIOED WITH HINGED AND LOCKABLE OR BOLTABU ACCESS PANELS. 3. GRATE SHALL BE STAINLESS STEEL. ALUMINUM OR STEEL STEEL GRATES SHALL BE HOT OIP GALVANIZED AND MAY BE HOT POWDER PAINTED AFTER GALVANIZING. 4. GRATE SHALL BE DESIGNED SUCH THAT THE DIAGONAL DIMENSION OF EACH OPENING IS SMALLER THAN THE DIAMETER OF THE OUTLET PIPE. 5. STRUCTURAL DESIGN OF GRATE SHALL BE BASED ON FULL HYOROSTATK; HEAD WTIH ZERO HEAD DOWNSTREAM OF ORATE. Flow-Through Planter Outlet Detail 99 City of Carisbad SUSMP— January 14, 2011 APPENDIX "C" Proprietary BMP Manufacturer Infornnation SECTION 4 PURESTREAM ™ Without a doubt, the most popular and most often specified Biofiltration device we manufacture. Drawing on the dismal failures of some of the stand-alone BioRetention "tree box systems", Katchall designed a single-vault system that includes ALL of the following features: 1. A properly designed BloFiltration System, 2. Pre-Entry trash / debris screen (coptures all materials > 3/8-Inch), 3. Filtered high-flow bypass chamber, {eliminates the need for secondary inlet structures), 4. Volume capture and treatrnent has been dramatically increased over competing products, 5. Draw-down times have been substanuallv decreased over competing products, (<2-hours). Katchall's PURESTREAM is the ONLY device that incorporates a hieh-flow bypass within the same structure as the filtration media, eliminating the need fora secondary curb inlet next to each device. (All other competing products [tree boxes] require a 2ndry Inlet to handle high-flow storm events) PURESTREAM BioFiltration Chambers are available in a variety of sizes, from our smallest 400 Series to our largest 2000 Series; units are configured so as to drain in virtually any direction. I.e. rear, sides, front. Every one of our systems is designed to capture and filter sheet flows up to a minimum of a 2S-year storm event, no other company - no other product is designed to treat discharges larger than "first- flush". Independent 3"* party testing has shown that a Model 6-4-4 captures and treats discharges @ 281.8-lnches per hour! NO OTHER PRODUCT ON THE MARKET COMES CLOSE TO THAT. Why specific, or ask your client to pay for a product that captures and filters LESS than 10% of the runoff from a small storm event? 90 % of the runoff generated is going straight into the secondary bypass inlet structure and is discharging direct Into our creeks, streams, rivers, lakes and oceans, WITHOUT ANY TREATMENT WHATSOEVER. IVasn't this just what the Clean Water Act was supposed to have prevented? In addition to our standard "off-the-shelf models, the Katchall PURESTREAM BioFiltration Chambers are available as custom design-build units and can include some of our most popular options such as: "Raw Steel" Grates in a variety of design - patterns, Powder-Coated Grates (multiple colors are available). Custom-designed Tree / Shrub Grates {your logo, project name, street name, etc.) Multiple Tree / Shrub Grate configurations (See Series 1200 ~ Series 2000), Colored stamped concrete finishes. Recessed Top Decks Including vegetation, brick pavers, etc. A variety of Park Benches, multiple colors and finishes are available. Benches can Include street names, logos, etc. embossed on top rails. Katchall Filtration Systems, LLC | www.katchall.net sum. IREE 08 SHRUB (PLtASE mxm KATCHAU. VOR K UST Of COUPAHaE SPECIES) 6" ACXCSS FOR niTER REPLACEMENT 36'x36" TREE (XAIE SIDEWALK W OTHER ADJACENT SURFACE INaUOES PRE-PLUMBED DBP IRRIGATIOM SYSTEM PIPES UAY OOTLtT SIDES OR BACK OF VAULT TYPICAL LOCAL DEPRESSION CURB INLET 6' CASI-BI-PUCE REiMfO«C£0 CO{;CREre VAULT simm mair N.T.S. KATCHALL nilRATiONSYSIEMS.aC 1-886-KATGHALL WWW.KATCHALL.NET PURESTREAM^* BIO-FiLTRATlON FOR LA FORESTA PROJECT REVISia<: A DW6 NUM; U FORESTA SHEET: 1 OF 3 Katchall Filtration Systems, LLC ] www.katchall.net Models / Sizes / Filtration Flow-Rates (Most specified - several other sizes are available / each series) Independent 3'^^ party testing has demonstrated (unobstructed) capture /filtration @ 181.8-inches/ hour Series Model Dimensions LxWxD Rear Discharge GPM Rear Discharge Cfs Side Discharge GPM Side Discharge Cfs 400 Series 4-4-4 4x4x4 41.9 5.6 43.9 5.8 600 Series 6-4-4 6x4x4 63.6 8.5 45.6 6.1 6-6-4 6x6x4 68.8 9.2 50.9 6.8 800 Series 8-4-4 8x4x4 83.8 11.2 49.4 6.6 8-6-4 8x6x4 91.3 12.2 92.0 12.3 1000 Series 10-4-4 10 X 4 x 4 103.9 13.9 53.1 7.1 10-6-4 10 x 6 X 4 123.4 16.5 106.2 14.2 1200 Series 12-4-4 12x4x4 124.9 16.7 56.9 7.6 12-6-4 12x6x4 148.1 19.8 114.4 15.3 1400 Series 14-4-4 14 X 4 X 4 145.9 19.5 61.3 8.2 14-6-4 14 x 6 X 4 173,5 23.2 122.7 16.4 1600 Series 16-4-4 16 X 4 X 4 166.8 22.3 65.1 8.7 16-6-4 16x6x4 197.5 26.4 130.2 17.4 1800 Series 18-4-4 18 X 4 X 4 187.8 25.1 68.8 9.2 18-6-4 18x6x4 222.9 29.8 137.6 18.4 2000 Series 20-4-4 20 X 4 X 4 208.7 27.9 72.6 9.7 20-6-4 20x6x4 247.6 33.1 145.9 19.5 Katchall Filtration Systems, LLC ] www.katchall.net Single Grate Configuration mfO. TREE OR SHRUB (HXASC CWTACr KATCHMX FOR A UST OF COHPAlBUt 5PEGES) ACCESS FDR WAWTENyiCE -v OF WinWCROaAL aTFR \ StOEV/AUC OR OTHER At)JACEK T SURFACE naiOEB FRE-PLUUBED OPSP RRCATlCfl S>S!EII PIPES MAY OlflLET SDE3 OR ayiK CF VAun IKEE CRATE iiiiffi TV7ICA1. LOCM. OEPIXSSIOli CURB IHIET 8* CA31-IH-Pt«e REmFDRCED COHCRETE VAUn M.T.S ADCES rai; ttAnTB<A)l[£ OF ANIIUKRtHAl FLIER -or coixBOE'ieR WML (StE OCTAL V) REAR DISCHfflflt; n.TS. riTS. 4' eetiCAETt >iER WAU. (SEC DETAL ACCESS FOR UAnTEHANCE or AMTWWWIfL FILIIR KATCHALL FILTHATtON 8YSTCMS> LLC 1-8684<ATCHALL WWW.KATCHALLNET PURESTREAM BIO-FILTRATION SYSTEM 40tK«ERIES REMSIDH: 0 rm, HUM: PURE40D SHEET: 1 OF 2 Katchall Filtration Systems, LLC | www.katchall.net Dual Grate Configuration INCLUDES Pm-PUMBB) ORP IRRICA1IQH s^ml PPES MAY WME! SIDES OR BACK CF VAULT SM'U THEE OR SHftPB (PUASE COMTACT KAtCHALl rCR A US1 OF CdiPATiaf SPtQES) ACCESS m mnmuKf. or AUHMCMGIH. RLTCR SIDEWALK OR OTHER ADJftCEJJT SURFACC 3t r3t TREE GRATE T>?ICAL LOCAL CEPRtSSWi INLET r C4STHH-PU1CE COflOm VWLT fl.T.S. MXISS FQR MMNTDIANCC OF AMTOCRDBIAL flLIW 4" COICBLTE WJR WALLS (SEt DETWL "A") mm H.T.& • 4' GOnCEETE ROB WAU (SEE OeVIL /-ACCESS njR / UANTtrWlCE OF AlfllMCROQM. FILRR 3DE DISCHARGC N.T.S. KATCHALL FimwriQN SYSTEMS. U-C 1-863-KATCHALL WWW.KATCHALLNET PURESTREAM™ BlO-FILTRATION SYSTEM 1200^ER1ES ftCVlSIOH; 0 owe HUM: PUREI200 SHEET: I OF 2 Katchall Filtration Systems, LLC | www.katchall.net Triple Grate or Park Bench Configuration SWAIL IREE OR 91RUB (FlEWt mnfict KAimiL FOR A usr CF CONPAIBU S'ECIES} ACCESS rem vmjtHfitcc DF mmavsBn HLTER SIDDVALK OR OTHER ADJACENT SURrACC ?4*»2«' TRtC BRATE TVaCAl LCCrt. DEPffiSaUM WODKS PKE-PUIkflED DBP iKRioAncrj sf/am RPEB MAV ouriEr goes Cfi BACK OF V-OJULr ADcesa ruK UAmainna. QF AHITidCROHAl FVIER INLET yratr xm mn. t' CUST-ltJ-PLACe raKFORceo O0f(CRETE VAUn M.T.S. STAHD^HD LASTlUr H.T.Si 4" DOflCRnE mn H'AILS (SEE CETAIL 'A*) 4 - 4* COHCRETE'itR WAU. pGE OCTAL "A") -ACCESS FOR mHTQIMISE OF AiiriMEROnAL RLIER aPE HSCHflRg. N.T.5. KATCHALL FILTRATION SYSTEMS, tlC l-«68-KATCHALL WWW.KATCHALLNET PUFIESTFIEAM™ BIO-FILTTWION SYSTEM 200(VSERIES REViSOH: 0 om HUM: PURE2000 SHECT: 1 OF 2 Katchall Filtration Systems, LLC 1 www.katchall.net Cf *N«(iiCRa)/.L n.Tj; / («t C^i. V.') -4-VARIES H-- »MrM6»C0'N. «l« WA.L own 'll'E-^ ti il ffi:cTi m. / tftBi 'I UTS. mo mf. Pa«nv; jtt -aicwi!. iiruMCN *• :o\c;tn w >.u. wiUv.ttiiwL wnmiz-t-i-iic* ntr/iFn *n:.\ N.tS. L «!iHcnu'.m ninR «(t;s w\Efs - ms'mzoi os .'ow-s COATED. 2 PRC HIMKJ ORP ISflOfilCH itSTSi 5 PCtlUfi WBl *1. -rtJ.lf,. 1 sniirmccs tc»i(5?c:c V,WLTS Aff c».si-iii-!=uc£ 4.5iA*»ir> uat tKA-ts Avy.'.iBii IV «.\viir sinrs "a wi"tv YOLR PMJ-CTS MSTVEBC.. 5 HC«HAR W.» IS aO-iEa^ASABJt OXOMJI MvSl MOXI mm cm A (FT) 0W8 OMC DWD (IN) TRAS« (CUfT) C<$CHARC-E PPES (W) («ri) {CTS) aTtstD nw (iTS) 81l?A.SS I TOWJ. i,-i-t 10 •5'-1Ii J.J 3.5 KATCHALL FILTRATION SYSTEMS, LLC 1-866-KATCHALL WWW.KATCHALL.NET PURESTREAM™ BIO-FILTRATION FOR WHOLE FOODS RICHMOND A FURE-WR SHEET: ? 0- 6 MODIFIED PURESTREAM - NO CURB INLET (Pipe In & Pipe Out) Katchall Filtration Systems, LLC | www.katchall.net