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Home My WebLink AboutCT 07-03; Robertson Ranch PA 14; Storm Water Management Quality; 2010-02-16STORM WATER MANAGEMENT PLAN 09-21 For ROBERTSON RANCH EAST VILLAGE PLANNING AREA 14 C.T. 07-03 September 30, 2009 Revised January 5, 2010 JN081245-5 Prepared For: Calavera Hills E, LLC. A California Limited Liability Company P.O. Box 85104 San Diego, CA 92186-5104 Prepared By: O'DAY CONSULTANTS 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92010 A i Allison McLaughlin RCE C69848 Declaration of Responsible Charge I hereby declare that I am the Engineer of Work for this project, that I have exercised responsible charge over the design of this project as defined in section 6703 of the Business and Professions Code, and that the design is consistent with current standards. I understand that the check of project drawings and specifications by the City of Carlsbad is confined to a review only and does not relieve me, as the Engineer of Work, of my responsibilities for the project design. O'Day Consultants, Inc. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92010 (760)931-7700 / / / /» /) Date: J Allison McLaughlin R.C.E. No. C69848 Exp. 9/30/10 Table of Contents Section 1.0 - Introduction and Vicinity Map Section 2.0 - Project Description Section 3.0 - Site Map (pocket) Section 4.0 - Pollutants and Conditions of Concern Section 5.0 - Site Design BMPS Section 6.0 - Source Control BMPs Section 7.0 - BMPs for Individual Priority Project Categories Section 8.0 - Structural Treatment BMPs Section 9.0 - Post Construction BMPs Maintenance Cost Responsibilities Attachments: 1. Vicinity map 2. Soils Group Map 3. San Diego Region Hydrologic Boundary Map 4. Beneficial uses for the hydrologic unit 5. 303(D) list for impaired water bodies 6. Table 2: Anticipated and potential pollutants 7. Tablel: Storm Water BMP Requirements Matrix 8. Project site plan & BMP map 9. LID Site Design BMPs 10. Source Control BMPs 11. Treatment Control BMPs 12. Curb Inlet Filter Sizing Calculations 13. BioClean Environmental Services, Inc. Grate Inlet Skimmer Box, Curb Inlet Basket, Nutrient Separating Baffle Box Report & Data 14. Hydrologic and Hydraulic Analysis for Robertson's Ranch East Village prepared by Chang Consultants September 2, 2004 15. Hydraulic Analysis for 84" RCP at Robertson's Ranch East Village prepared by Chang Consultants April 27, 2005 16. Attachment 12: Vegetated Swale Sizing Calculations of the Preliminary Storm Water Management Plan for Robertson's Ranch East Village prepared by O'Day Consultants April 8, 2004 updated November 30, 2006 17. Storm Water Standards Questionnaire (City of Carlsbad, Form E-34) Section 1.0 Introduction and Vicinity Map This Storm Water Management Plan was prepared to support the application for construction plans of Planning Area 14, a 16-lot single family residential development located within Lot 4 of Robertson Ranch East Village, CT 02-16, in the City of Carlsbad, County of San Diego, State of California, according to Map No. 15608. See Attachment 1 for Vicinity Map. Section 2.0 Project Description P. A. 14 is a 3.65 acre site located north of Glen Avenue and west of Wind Trail Way. A Tentative Map has been approved for this site. Several studies have been prepared for this project as follows: 1. Reference 1: Preliminary Storm Water Management Plan for Robertson Ranch, dated April 8, 2004 and revised November 30, 2006 by O'Day Consultants (A portion of Reference 1 is included herein as Attachment 16); and, 2. Reference 2: Drainage Study for Robertson Ranch East Village, P.A. 14 dated September 22, 2006 and last revised September 30, 2009 by O'Day Consultants; and, 3. Reference 3: Drainage study for Robertson Ranch East Village, CT 02-16 dated July 30, 2005, revised December 13, 2005, June 6, 2006 and November 30, 2006, by O'Day Consultants The existing site has been mass graded per Grading Plans for Robertson Ranch East Village, City of Carlsbad Dwg. 433-6A (Reference 5). In this report, the planned mass graded site is referred to as "existing conditions." Existing Conditions The project is located in the Los Monos Hydrologic Subarea (904.31) of the Agua Hedionda Watershed in the Carlsbad Hydrologic Unit in the San Diego Region. (See Attachment 3) Under existing conditions, Lot 4 is mass graded with a temporary desiltation basin. The temporary desiltation basin drains via a 24" RCP storm drain connecting to a 48" RCP storm drain on Wind Trail Way. This storm drain ultimately drains to the 84" storm drain. A low-flow pipe connected to the 84" storm drain will carry the water across Cannon Rd. to the south into a vegetated swale in Lot 7 of Ct 02-16, Planning Area 20. The vegetated swale will perform as a flow-based BMP and therefore will be designed to mitigate the maximum flow rate of runoff produced from a rainfall intensity of 0.2 inches/hour for each hour of a storm event (See Vegetated Swale Sizing Calculations, Attachment 16). Proposed Conditions 16 single-family residential lots are proposed for the site. See Attachment 8 for the site plan and Reference 2 for a hydrologic map showing proposed conditions. The storm water runoff discharge point off the site remains essentially the same, to the 48" storm drain at the southeast corner of the site. The estimated flow to this pipe for the 100-year event with proposed conditions is 92.26 cfs. (Reference 2). It should be noted that the northern 7 lots will drain to Alander Court and enter the storm drain system via curb inlets at the low point. The runoff will then flow through the storm drain system until it reaches the 48" storm drain system in Wind Trail Way. Hence, all the runoff from PA 14 is ultimately conveyed and treated by the vegetated swale in P.A. 20. Priority Project Determination The City of Carlsbad SUSMP dated June 2008 provides a Storm Water Standards Questionnaire (Appendix A) and to determine a project's permanent and construction storm water BMP requirements. (See Attachment 17). The results are summarized below: This project meets Priority Project Requirements. Must comply with the priority project standards and a Storm Water Management Plan must be submitted. Storm Water Pollution Prevention Plan Federal, state and local agencies have established goals and objectives for storm water quality in the region. The project, prior to the start of construction activities, will comply with all federal, state and local permits including the National Pollution Discharge Elimination System (NPDES) from the Regional Water Quality Control Board and the erosion control requirements from the City of Carlsbad grading ordinance. Compliance with the NPDES requires the applicant to file a Notice of Intent (NOI) with the State Water Quality Control Board (SWQCB), apply Best Management Practices (BMPs) and develop a storm water pollution prevention plan (SWPPP). A Notice of Intent has been filed, WDID 9 37C344227, and a SWPPP has been prepared by O'Day Consultants dated September 30, 2009. The SWPPP shall be kept on site during construction. Section 3.0 Attachment 8 - Site Map Section 4.0 Pollutants and Conditions of Concern '"W- Pollutants of Concern According to the Proposed 2006 CWA Section 303(d)s list published by the RWQCB (attachment 5), Agua Hedionda Lagoon is an impaired water body associated with the direct stormwater discharge from this project. Agua Hedionda Lagoon has low priority impairment for bacteria indicators and low priority impairment for sedimentation and siltation. Sites tributary to clean water act section 303(D) water bodies require additional BMP implementation. Drainage infrastructure downstream and detention basins upstream are designed to handle post- development storm runoff from the East Village. Refer to the Hydrologic and Hydraulic Analysis for Robertson's Ranch East Village prepared by Chang Consultants September 2, 2004 and Hydraulic Analysis for 84" RCP at Robertson's Ranch East Village prepared by Chang Consultants April 27, 2005 for details on expected impacts. (See attachments 14 & 15) Soil Characteristics A soils report for the site has been prepared by GeoSoils, Inc. titled "Geotechnical Evaluation of the Robertson Ranch Property, City of Carlsbad, San Diego County, California." On January 29, 2002. The project area consists of soils groups A,B,C, and D, with the majority of soil being group D. See soils group map, attachment 2. Potential Discharges The project will contain some pollutants commonly found on similar developments that could affect water quality. The following list is taken from Table 2 of the City of Carlsbad's Storm Water Standards Manual (attachment 6). It includes anticipated pollutants for detached residential developments and streets. 1. Sediment discharge (Agua Hedionda Lagoon Impairment) 2. Nutrients from fertilizers 3. Heavy metals 4. Organic compounds 5. Trash and debris 6. Oxygen demanding substances 7. Oil and grease from paved areas 8. Bacteria and viruses (Agua Hedionda Lagoon Impairment) 9. Pesticides from landscaping and home use Conditions of Concern The hydrologic and hydraulic analysis for the project (Reference 2) indicates that the project will generate the following flow rates for pre- and post-development conditions: Location 24" storm drain at southeast corner of site Total Qioo(cfs) Pre-development (Mass Graded Site) 12.23 12.23 Post-development (Per of PA 16, 17 &18) 6.51 6.51 Post-development (Per PA 14) 4.6 4.6 Section 5.0 Low Impact Development (LID) Site Design BMPs To address water quality for the project, BMPs will be implemented during construction and post construction. Required BMPs are selected from Table 1: Storm Water BMP requirements Matrix, of the City of Carlsbad's Storm Water Standards Manual (attachment 7). Control of post-development peak storm water runoff discharge rates and velocities is desirable in order to maintain or reduce pre-development downstream erosion. The following list provides LID site design measures chosen for this site to help avoid or reduce potential impacts. These measures will control post-development peak storm water runoff discharge rates and velocities to maintain or reduce pre-development downstream erosion and to protect stream habitat. The major principles for site design BMP's are 1) to maintain pre-development rainfall runoff characteristics and 2) to protect slopes and channels. (See attachment 9 for details): Vegetated Buffer Strips: All front yards shall be planted with grass to treat runoff from each lot individually before draining to undersidewalk drains located at back of sidewalk. Biofilters: A biofilter, or vegetated swale as it is referred to here, has been built to the south of Cannon Rd. and will treat the low-flow runoff from the East Village. See Section 8.0 for further discussion. Street Design: Local streets will minimize impervious area by having a 36' curb-to-curb distance and a 6.5' landscaped area on both sides of the street. Development Clustering: Establishing planning areas in clusters accomplishes several desirable effects. Drainage systems service only developed areas reducing the amount of debris, siltation, and sedimentation associated with natural drainage courses. Natural drainage courses are preserved maintaining existing hydrologic regimes. Smaller basins are established with multiple distributed outlets minimizing flow concentrations Conserve Natural Areas: The project site will be mass-graded in accordance with Drawing 433-6A and will be cleared of vegetation. However, the Robertson Ranch Master Plan dedicates approximately 70.1 acres of open space at the East Village to the City of Carlsbad. This will conserve approximately 46.5% of the natural vegetation and topography for the East Village. The natural drainage channel dividing the east and west village will be left in a natural, undisturbed condition. Minimize Directly Connected Impervious Areas: To the maximum extent practicable, parking lots, sidewalks, patios, roof top drains, rain gutters, and other impervious surfaces shall drain into adjacent landscaping prior to discharging to the storm water conveyance system. Protect Slopes and Channels: All runoff will be safely conveyed away from the tops of slopes. Energy dissipaters shall be installed at the outlets of new storm drains, culverts, or channels that enter unlined channels in accordance with applicable standards and specifications to minimize erosion. All slopes and landscape areas will have permanent landscaping consistent with the Carlsbad Landscape Manual to prevent erosion of sediment. Rip-rap is being installed downstream of the low-flow pipe that outlets to the vegetative swale on Planning Area 20. This will decrease velocity down- stream and prevent erosion. Section 6.0 Source Control BMPs Source Control BMPs help minimize the introduction of pollutants and sedimentation into storm water in order to maintain or reduce pre-development levels of pollutants by applying the following concepts (See attachment 10 for details): Street Sweeping: City maintained streets will be swept routinely in order to reduce introduction of trash, debris, sediment and siltation into drainage systems. Trash Storage Areas to Reduce Pollution Introduction: HOA shall encourage homeowners to use trash containers with attached lids that exclude rain or contain a roof or awning to minimize direct precipitation. In addition, homeowners shall be encouraged to limit the time trash containers remain outside after scheduled pickup. Use Efficient Irrigation Systems & Landscape Design: HOA shall encourage homeowners to use irrigation systems that employ rain shutoff devices to prevent irrigation during precipitation and that are designed to each landscape area's specific water requirements consistent with the Carlsbad Landscape Manual. Maintenance of HOA areas will be performed by contract with a professional maintenance company. Provide Storm Water Conveyance System Stenciling and Signage: All storm water conveyance inlets and catch basins shall provide concrete stamping, porcelain tile, inset permanent marking or equivalent as approved by the City of Carlsbad within the project area with prohibitive language satisfactory to the City Engineer. Education: The homeowners association will be responsible for periodically providing the homeowners with informational packets regarding car washing, lawn & garden care, motor oil and pet waste, and the CC&Rs will include restrictions on these activities. Section 7.0 BMPs for Individual Priority Project Categories Hillside landscaping: Hillside areas disturbed by project development shall be landscaped with deep-rooted, drought tolerant plant species selected for erosion control, in accordance with the Carlsbad landscape Manual. Section 8.0 Structural Treatment BMPs As identified in Table 1, attachment 7, a combination of treatment control BMPs shall be incorporated into the project. The project has been designed so that runoff is treated by Site Design BMPs prior to Structural Treatment BMPs. Vegetated Swale: A numerically-sized vegetated swale has been constructed and utilized to treat the low- flow runoff from the East Village development. The swale is 825' long and the width varies from 40' to 85'. The swale has a slope of 0.4%, producing a velocity in the swale less than 1 fps. The considerable length and low velocity allows maximum pollutant removal. The pollutants that the vegetated swale efficiently removes include sediment, nutrients, trash, metals, bacteria, oil, grease, and organics. (See Attachment 11, TC-30 fact sheet) The Robertson Ranch East Village HOA is responsible for the maintenance of the vegetated swale. However, until the planning areas have been developed, the owner/developer will be responsible for the maintenance. The vegetated swale is located south of Cannon Rd. in lot 7 of CT 02-16. The area has been designated for a water quality facility on the HMP Hardline Map, Figure 3-6 of the Robertson Ranch Master Plan. In addition, the Biology Map, Figure 5.5-1, of the master plan shows the area is currently used as agriculture. As a result, no environmentally sensitive areas will be impacted. (See Vegetated Swale Sizing Calculations, Attachment 16). Attachment 16 shows the sizing calculations from Reference 1 along with updated calculations to ensure that the minor change in the drainage basin along Glen Avenue, an overall increase of 0.79 acres, does not affect the design and function of the Vegetated Swale as laid out in Reference 1. See Drainage Study for Robertson Ranch East Village Planning Area 14 CT 07-03 prepared by O'Day Consultants September 22, 2006 and updated September 30, 2009 for detailed drainage basin boundaries. Vegetated Buffer Strips: Although not numerically required as a treatment train, all front yards shall be planted with grass to treat runoff from each lot individually before draining to the streets. Vegetated buffer strips have a high removal efficiency for sediment in addition to being effective in removing other pollutants. Inlet filters: Although not numerically required as a treatment train, the drainage inserts will be curb inlet baskets by Suntree Technologies, Inc. The curb inlet baskets will also include hydrocarbon absorption booms to collect oil and grease. Drainage inserts will be installed at every onsite curb inlet. See attachment 13 for product information and sample data. The combination of these BMPs together with the site and source control BMPs sited above maximizes pollutant removal efficiency for the particular pollutants of concern to the maximum extent practicable. Section 9.0 Post Construction BMPs Maintenance Cost Responsibilities The following post-construction BMPs shall be owner or HOA-maintained: 1. All planted slopes and landscaped areas 2. Efficient irrigation systems & landscape design 3. Storm drain inlet stenciling and signage 4. Education 5. Storm drain inlets fitted with "Bio Clean" grated basket inserts with hydrocarbon absorption booms 6. Vegetated swale (PA 20, south of Cannon Road) The table that follows lists post-construction BMPs, maintenance responsibility and estimated cost. BMPs Source Control Maintenance Cost Efficient Irrigation and Landscape Design (SD-12) Owner responsibility Storm Drain Signage (SD-13) H.O.A./owner yearly inspection and repaint or replace Education Treatment Control H.O.AVowner periodic distribution of informational packets Budget by the H.O. A. Est. $500.00 Budget by the H.O.A. Drain Inserts (MP-52) Vegetated Swale (TC-30) H.O.AVowner responsibility Inspect 2 times per year (min) (before rain season, and after major storm events) Clean screen and replace hydro-carbon filter at least once per year before rainy season Master H.O.A. responsibility Est. $200 per insert Budget by the H.O.A. ^ Attachment 1 SITE dJY OF OCEANSIDE HIGHWAY,^* ! a JY QF VISTA CITY OF SAN MARCO PACIFIC OCEAN an OF ENQNITAS VICINITY MAP VICINITY MAP FOR ROBERTSON RANCH PA 14 NO SCALE Attachment 2 Attachment 3 Attachment 4 c Table 2-2. BENEFICIAL USES OF INLAND SURFACE WATERS 1,2 Inland Surface Waters .Hydrologic Unit Basin Number M U N A 6 R I N D P R 0 C G W R F R S H P 0 W R E C 1 R E C 2 B I 0 L San Diego Courtly Coastal Stream* -continued Buena Vista Lagoon Buena Vista Creek Buena Vista Creek Agua H&dtonda Agua Hedbnda Creek Buena Creek Agua Hedionda Creek Letterbox canyon Canyon de las Endnas San Marcos Creek Watershed Batiquitos Lagoon San Marcos Creek unnamed Intermittent streams San Marcos Creek Watershed San Marcos Creek Encinitas Creek 4.21 4.22 451 4.31 4.32 4.32 4.31 4.31 4.40 4.51 4.52 4.53 4.51 4.51 • Existina Beneficial Use 1 ,A,^^^; „. + + • • • • + • • • • • • • • • • • • W A R M BOB c 0 L D = W I L D ^= R A R E == S P W N :— — u See Coastal Waters- Table 2-3 • • • • • • See Coastal Waters- Table 2-3 • • • • o • • • • • • • • • • .• • • • • • • • See Coastal Waters- Table 2-3 + + + + feu) Ml • • • • .UI_t_ A —- U oats ana •• • • •O^BM • • • ••«••^Bt • • ••••^•M •=s HMm.« BBSS • • • ^M^^MN •=3=3= ••i^iMMMa =s= •MM^IM == O Potential Beneficial Use + Excepted From MUN (See Text) Waterbodies are listed multiple times if they cross hydrologic area or sub area boundaries. Beneficial use designations apply to all tributaries to the indkated waterbody. if not listed separately. Table 2-2 BENEFICIAL USES 2-27 March 12, 1997 TabL 2-3. BENEFICIAL USES 0 Coastal Waters Pacific Ocean Dana Point Harbor Del Mar Boat Basin Mission Bay Oceanside Harbor San Diego Bay Coastal Lagoons Tijuana River Estuary Mouth of San Diego River Los Penasquitos Lagoon San Dieguito Lagoon Batiquitos Lagoon San Elijo Lagoon Aqua Hedionda Lagoon Hydrologic Unit Basin Number 11.11 7.11 6.10 5.11 4.51 5.61 •*1 F COASTAL WATERS 1 N D • • N A V • H E C 1 * • • • • • • ' •BBI R E C 2 • • • • • • • BBS C .0 M M • • • •BBS B I 0 L BBES E S T • • osse w I L D • • • • • BBSB* R A R E • 9 • • • BBBBJ M A R • • • • • •BBS: A Q U A BSBS M I G R • • • • • • • • ' • • • BBSS S p w N • • • • • • • • • • • aaae W A R M == S H E L L • • • • • • • • • •BBBB 1 Includes the tidal prisms of the Otay and Sweetwater Rivers. 2 Fishing from shore or boat permitted, but other water contact recreational (REC-1) uses are prohibited. • Existing Beneficial Use Table 2-3 BENEFICIAL USES March 12, 1997 2-47 Attachment 5 PROPOSED 2006 CWA SECTION 303(d) LIST OB*., ATER QUALITY LIMITED SEGMENTS SAN DIEGO REGIONAL BOARD SWRCB APPROVAL DATE: OCTOBER 25,2006 REGION TYPE NAME CALWATER WATERSHED POLLUTANT/STRESSOR POTENTIAL SOURCES ESTIMATED PROPOSED TMDL SIZE AFFECTED COMPLETION 9 R Agua Hedionda Creek 9 E Agua Hedionda Lagoon 9 R Aliso Creek 90431000 90431000 90113000 Manganese Selenium Sulfates Total Dissolved Solids Indicator bacteria Sedimentation/SUtation Source Unknown Source Unknown Source Unknown Urban RunofffStonn Sewers Unknown Nonpoint Source Unknown point source Nonpoint/Point Source Nonpoint/Point Source 7 Miles 7 Miles 7 Miles 7 Miles 2019 2019 2019 2019 6.8 Acres 6.8 Acres 19 Miles 2006 2019 2005Indicator bacteria This listing for indicator bacteria applies to the Aliso Creek mainstem and all the major tributaries of Aliso Creek which are Sulphur Creek, Wood Canyon, Aliso Hills Canyon, Dairy Fork, and English Canyon. Urban Runoff/Storm Sewers Unknown point source Nonpoint/Point Source Phosphorus 19 Miles 2019 This listing for phosphorus applies to the Aliso Creek mainstem and all the major tributaries of Aliso Creek which are Sulphur Creek, Wood Canyon, Aliso Hills Canyon, Dairy Fork, and English Canyon. Urban Runoff/Storm Sewers Unknown Nonpoint Source Unknown point source Page 1 of 27 Attachment 6 2.3 PERMANENT BEST MANAGEMENT PRACTICES SELECTION PROCEDURE 2.3.1 INTRODUCTION The following process should be followed to determine the permanent BMPs for the applicant's project. 2.3.2 IDENTIFY POLLUTANTS AND CONDITIONS OF CONCERN 2.3.2.1 Identify Pollutants from the Project Area Using Table 2 below, identify the project's anticipated pollutants. Pollutants associated with any hazardous material sites that have been remediated or are not threatened by the proposed project are not considered a pollutant of concern. Projects meeting the definition of more than one project category shall identify all general pollutant categories that apply. Descriptions of the general pollutant categories listed in Table 2 are defined in Appendix F under the definition of "pollutants of concern." ' Table 2 Anticipated and Potential Pollutants Generated by Land Use Type Project Categories Detached Residential Development Attached Residential Development Commercial Development >100,000ft2 Heavy industry /industrial development Automotive Repair Shops Restaurants Steep Hillside Development >5,000 ft2 Parking Lots Retail Gasoline Outlets Streets, Highways & Freeways General Pollutant Categories Sediments X X pO) X X p(1) X Nutrients X X p(D X pd) p(i) Heavy Metals X X X X X Organic Compounds p(2) X X<4)(5) X X<4) Trash & Debris X X X X X X X X X X Oxygen Demanding Substances X p(D p(5) X X X p(1) X p(5) Oil& Grease X p(2) X X X X X X X X Bacteria & Viruses X p(i) p(3) X Pesticides X X p(5) X p(1) X = anticipated P = potential (1) A potential pollutant if landscaping exists on-site. (2) A potential pollutant if the project includes uncovered parking areas. (3) A potential pollutant if land use involves food or animal waste products. (4) Including petroleum hydrocarbons. (5) Including solvents. SVVMP Rev 6.4,08 Attachment 7 Table 1 Standard Development Project & Priority Project Storm Water BMP Requirements Matrix Standard Projects LID Site Design BMPs(1) R Source Control BMPs'21 R BMPs Applicable to Individual Priority Project Categories'3' wTJcoO(Y 0) "co (X co R CO0)3O _ <* CO CO ~ >• k 5 gS oj-j (/>>-£CD 'C COQL Q 0. J3 R COCO ooQ d R co>% COcu 8 CO Mainten-a R </>CO ^<; C/5CO VehicleCU R j=. U)co "^ fl) Q. CO•= co o-Si UJ < «4-^ R O) V)CO0) P Q.OutdoorAreasd) R O)c -£ o.SurfaceAreas.C R OT COCD < CJ) "oj LL •- R en Q.COo03TJ CO Hillside•- R Treatment Control BMPs<4) O Priority Projects: Detached Residential Development Attached Residential Development Commercial Development greater than 100,000ft2 Heavy industry /industrial Automotive Repair Shop Restaurants Steep Hillside Development greater than 5,000 ft2 Parking Lots Retail Gasoline Outlets Streets, Highways & Freeways R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R R(5) R R R R R S S S S S S S S S S R = Required; select one or more applicable and appropriate BMPs from the appl cable steps in Section III.2.A-D, or equivalent as identified in Appendix B. O = Optional/ or may be required by C ty staff. As appropriate, applicants are encouraged to incorporate treatment control BMPs and BMPs applicable to individual priority project categories into the project design. City staff may require one or more of these BMPs, where appropriate. S = Select one or more applicable and appropriate treatment control BMPs from Appendix B. (1) Refer to Chapter 2.3.3.1. LID = Low Impact Development. (2) Refer to Chapter 2.3.3.2. (3) Priority project categories must apply specific storm water BMP requirements, where applicable. Priority projects are subject to the requirements of all priority project categories that apply. Refer to Chapter 2.3.3.3 (4) Refer to Chapter 2.3.3.4 (5) Applies if the paved area totals >5,000 square feet or with >1 5 parking spaces and is potentially exposed to urban runoff. SVVMP Rev 6 4,()X Attachment 8 Attachment 9 "-C Section 3 Site and Facility Design for Water Quality Protection 3.1 Introduction Site and facility design for stormwater quality protection employs a multi-level strategy. The strategy consists of: i) reducing or eliminating post-project runoff; 2) controlling sources of pollutants; and 3), if still needed after deploying i) and 2), treating contaminated stormwater runoff before discharging it to the storm drain system or to receiving waters. This section describes how elements i), 2), and 3) of the strategy can be incorporated into the site and facility planning and design process, and by doing so, eliminating or reducing the amount of stormwater runoff that may require treatment at the point where stormwater runoff ultimately leaves the site. Elements i) and 2) may be referred to as "source controls" because they emphasize reducing or eliminating pollutants in stormwater runoff at their source through runoff reduction and by keeping pollutants and stormwater segregated. Section 4 provides detailed descriptions of the BMPs related to elements i) and 2) of the strategy. Element 3) of the strategy is referred to as "treatment control" because it utilizes treatment mechanisms to remove pollutants that have entered stormwater runoff. Section 5 provides detailed descriptions of BMPs related to element 3) of the strategy. Treatment controls integrated into and throughout the site usually provide enhanced benefits over the same or similar controls deployed only at the "end of the pipe" where runoff leaves the project site. 3.2 Integration of BMPs into Common Site Features Many common site features can achieve stormwater management goals by incorporating one or more basic elements, either alone or in combination, depending on site and other conditions. The basic elements include infiltration, retention/detention, biofilters, and structural controls. This section first describes these basic elements, and then basin for tttOtmmt describes how these elements can be incorporated into common site features. Infiltration Infiltration is the process where water enters the ground and moves downward through the unsaturated soil zone. Infiltration is ideal for management and conservation of runoff because it filters pollutants through soil and restores natural flows to groundwater and downstream water bodies. See Figure 3-1- Figure 3-1 Infiltration Basin ^nfnd Facility Design for Water Quality Protection The infiltration approach to storm water management seeks to "preserve and restore the hydrologic cycle." An infiltration stormwater system seeks to infiltrate runoff into the soil by allowing it to flow slowly over permeable surfaces. The slow flow of runoff allows pollutants to settle into the soil where they are naturally mitigated. The reduced volume of runoff that remains takes a long time to reach the outfall, and when it empties into a natural water body or storm sewer, its pollutant load is greatly reduced. Infiltration basins can be either open or closed. Open infiltration basins, include ponds, swales and other landscape features, are usually vegetated to maintain the porosity of the soil structure and to reduce erosion. Closed infiltration basins can be constructed under the land surface with open graded crushed stone, leaving the surface to be used for parking or other uses. Subsurface closed basins are generally more difficult to maintain and more expensive than open filtration systems, and are used primarily where high land costs demand that the land surface be reclaimed for economic use. Infiltration systems are often designed to capture the "first flush" storm event and used in combination with a detention basin to control peak hydraulic flows. They effectively remove suspended solids, particulates, bacteria, organics and soluble metals and nutrients through the rehiclg of filtration, absorption and microbial decomposition. Groundwater contamination ib/, i->e considered as a potential adverse effect and should be considered where shallow dwater is a source of drinking water. In cases where groundwater sources are deep, there ^ «t very low chance of contamination from normal concentrations of typical urban runoff. detention and Detention letention and detention systems differ from infiltration systems primarily in intent. Detention ystems are designed to capture and retain runoff temporarily and release it to receiving waters t predevelopment flow rates. Permanent pools of water are not held between storm events, 'ollutants settle out and are removed from the water column through physical processes. See igure 3-2. .etention systems capture runoff and retain it etween storms as shown in Figure 3-3. /ater held in the system is displaced by the ext significant rainfall event. Pollutants ;ttle out and are thereby removed from the ater column. Because the water remains in te system for a period of time, retention 'stems benefit from biological and ochemical removal mechanisms provided by niatic plants and microorganisms. See gure3-3. ofeniogfor reduced outflow biuinfor settlement Figure 3-2 Simple Detention System Section 3 Site and Facility Design for Water Quality Protection tssss fainting Iteti Figure 3-3 Retention System Retention/detention systems may release runoff slowly enough to reduce down stream peak flows to their pre-development levels, allow fine sediments to settle, and uptake dissolved nutrients in the runoff where wetland vegetation is included. Bioretention facilities have the added benefit of aesthetic appeal. These systems can be placed in parking lot islands, landscaped areas surrounding buildings, perimeter parking lots and other open space sections. Placing bioretention facilities on land that city regulations require developers to devote to open space efficiently uses the land. An experienced landscape architect can choose plant species and planting materials that are easy to maintain, aesthetically pleasing, and capable of effectively reducing pollutants in runoff from the site. Constructed wetland systems retain and release stormwater in a manner that is similar to retention or detention basins. The design mimics natural ecological functions and uses wetland vegetation to filter pollutants. The system needs a permanent water source to function properly and must be engineered to remove coarse sediment, especially construction related sediments, from entering the pond. Stormwater has the potential to negatively affect natural wetland functions and constructed wetlands can be used to buffer sensitive resources. Biofilters Biofilters, also known as vegetated swales and filter strips, are vegetated slopes and channels designed and maintained to transport shallow depths of runoff slowly over vegetation. Biofilters are effective if flows are slow and depths are shallow (3% slope max.). The slow movement of runoff through the vegetation provides an opportunity for sediments and particulates to be filtered and degraded through biological activity. In most soils, the biofilter also provides an opportunity for stormwater infiltration, which further removes pollutants and reduces runoff volumes. See Figure 3-4. side slope vegetation, tolerates ptriodic imiumtation Figure 3-4 Vegetated Swale Swales intercept both sheet and concentrated flows and convey these flows in a concentrated, vegetation-lined channel. Grass filter strips intercept sheet runoff from the impervious network of streets, parking lots and rooftops and divert stormwaters to a uniformly graded meadow, buffer zone, or small forest. Typically the vegetated swale and grass strip planting palette can 3 , ^g^nd Facility Design for Water Quality Protection comprise a wide range of possibilities from dense vegetation to turf grass. Grass strips and vegetated swales can function as pretreatment systems for water entering bioretention systems or other BMPs. If biofilters are to succeed in filtering pollutants from the water column, the planting design must consider the hydrology, soils, and maintenance requirements of the site. Appropriate plantings not only improve water quality, they provide habitat and aesthetic benefits. Selected plant materials must be able to adapt to variable moisture regimes. Turf grass is acceptable if it can be watered in the dry season, and if it is not inundated for long periods. Species such as willows, dogwoods, sedge, rush, lilies and bulrush species tolerate varying degrees of soil moisture and can provide an attractive plant palette year round. Structural Controls Structural controls in the context of this section include a range of measures that prevent pollutants from coming into contact with stormwater. In this context, these measures may be referred to as "structural source controls" meaning that they utilize structural features to prevent pollutant sources and stormwater from coming into contact with one another, thus reducing the opportunity for stormwater to become contaminated. Examples of structural source controls include covers, impermeable surfaces, secondary containment facilities, runoff division berms, and diversions to wastewater treatment plants. ..1 Streets More than any other single element, street design has a powerful impact on stormwater quality. Street and other transportation related structures typically can comprise between 60 and 70% of the total impervious coverage in urban areas and, unlike rooftops, streets are almost always directly connected to an underground stormwater system. Recognizing that street design can be the greatest factor in development's impact on stormwater quality, it is important that designers, municipalities and developers employ street standards Lhat reduce impervious land coverage. Directing runoff to biofilters or swales rather than inderground storm drains produces a street system that conveys stormwater efficiently while providing both water quality and aesthetic benefits. Dn streets where a more urban character is desired, or where a rigid pavement edge is required, :urb and gutter systems can be designed to empty into drainage swales. These swales can run mrallel to the street, in the parkway between the curb and the sidewalk, or can intersect the treet at cross angles, and run between residences, depending on topography or site planning, lunoff travels along the gutter, but instead of being emptied into a catch basin and underground »ipe, multiple openings in the curb direct runoff into surface swales or infiltration/detention iasins. n re^fjiit years new street standards have been gaining acceptance that meets the access Rr W-nents °f l°cal residential streets while reducing impervious land coverage. These ards create a new class of street that is narrower and more interconnected than the current jcal street standard, called an "access" street. An access street is at the lowest end of the street ierarchy and is intended only to provide access to a limited number of residences. Section 3 Site and Facility Design for Water Quality Protection Street design is usually mandated by local municipal standards. Officials must consider the scale of the land use as they select stormwater and water quality design solutions. Traffic volume and speeds, bicycle lane design criteria, and residential and business densities influence the willingness of decision makers to permit the narrow streets that include curbless design alternatives. Emergency service providers often raise objections to reduced street widths. Street designs illustrated here meet national Fire Code standards for emergency access. An interconnected grid system of narrow streets also allows emergency service providers with multiple access routes to compensate for the unlikely possibility that a street may be blocked. Many municipal street standards mandate 80 to 100% impervious land coverage in the public right-of-way, and are a principal contributor to the environmental degradation caused by development. A street standard that allows an interconnected system of narrow access streets for residential neighborhoods has the potential to achieve several complimentary environmental and social benefits. A hierarchy of streets sized according to average daily traffic volumes yields a wide variety of benefits: improved safety from lower speeds and volumes, unproved aesthetics from treet trees and green parkways, reduced impervious land coverage, less heat island effect, and lower development costs. If the reduction in street width is accompanied by a drainage system that allows for infiltration of runoff, the impact of streets on stormwater quality can be greatly mitigated. There are many examples of narrow streets, from both newly constructed and older communities, which demonstrate the impact of street design on neighborhood character and environmental quality. See Table 3-1. Table 3-1 Adopted Narrow Street Standards (Typ. Cross-Sections, two-way traffic) City of Santa Rosa CityofPalmdale City of San Jose CityofNovato ""County of San Mateo 30 ft wide with parking permitted both sides, <iooo Average Daily Traffic (ADT) 26 - 28 ft with parking permitted one side 20 ft - no parking permitted 20 ft neck downs at intersections 28 ft wide with parking permitted both sides 30 ft wide with parking permitted both sides, <ai Dwelling Units (DU) 34 ft wide with parking permitted both sides, <121 DU 24 ft wide with parking permitted both sides, 2-4 DU 28 ft with parking permitted both sides, 5-15 DU 19 ft wide rural pavement cross-section with parking permitted on adjacent gravel shoulders A comparison of street cross-sections is shown in Figure 3-5. in 3 """"Sra/ Facility Design for Water Quality Protection RURAL 19'DavemefltpafkJhghoi) gravel shoyHerdrainage In gravel swale no sldaviajkr shared spaca 32% impervious land coverage NtelK Aama^m.onaeteBu.ter Sldewafc.both sides rio.<jtree<fre>t8'3%lrrjpefvlbua land coverage Figure 3-5 Comparison of Street Cross-Sections (two-way traffic, residential access streets) 3.2.2 Parking Lots !n any development, storage space for stationary vehicles can consume many acres of land area, >ften greater than the area covered by streets or rooftops. In a neighborhood of single-family lomes, this parking area is generally located on private driveways or along the street. In higher lensity residential developments, parking is often consolidated in parking lots. I i **pace for storage of the automobile, the standard parking stall, occupies only 160 ft2, but aen combined with aisles, driveways, curbs, overhang space, and median islands, a parking lot :an require up to 400 ft2 per vehicle, or nearly one acre per 100 cars. Since parking is usually iccommodated on an asphalt or concrete surface with conventional underground storm drain ystems, parking lots typically generate a great deal of DCIA. Section 3 Site and Facility Design for Water Quality Protection There are many ways to both reduce the impervious land coverage of parking areas and to filter runoff before it reaches the storm drain system. Hybrid Parking Lot Hybrid lots work on the principle that pavement use differs between aisles and stalls. Aisles must be designed for speeds between 10 and 20 mph, and durable enough to support the concentrated traffic of all vehicles using the lot. The stalls, on the other hand, need only be designed for the 2 or 3 mph speed of vehicles maneuvering into place. Most of the time the stalls are in use, vehicles are stationary. Hybrid lots reduce impervious surface coverage in parking areas by differentiating the paving between aisles and stalls, and combining impervious aisles with permeable stalls, as shown in Figure 3-6. imperviow aisle permeable stalls Figure 3-6 Hybrid Parking Lot If aisles are constructed of a more conventional, impermeable material suitable for heavier vehicle use, such as asphalt, stalls can be constructed of permeable pavement. This can reduce the overall impervious surface coverage of a typical double loaded parking lot by 60% and avoid the need for an underground drainage system. Permeable stalls can be constructed of a number of materials including pervious concrete, unit pavers such as brick or stone spaced to expose a permeable joint and set on a permeable base, crushed aggregate, porous asphalt, turf block, and cobbles in low traffic areas. Turf blocks and permeable joints are shown in Figures 3-7 and 3-8. 'otdsitting b Figure 3-7 Turf Blocks natural stmu ftrmatUtjoint materials (*»*> sand sitting bed reservoir base course Figure 3-8 Permeable Joints c \nunnd Facility Design for Water Quality Protection Parking Grove A variation on the permeable stall design, a grid of trees and bollards can be used to delineate parking stalls and create a "parking grove." If the bollard and tree grids are spaced approximately 19 ft apart, two vehicles can park between each row of the grid. This 9.5 ft stall spacing is slightly more generous that the standard 8.5 to 9 ft stall, and allows for the added width of the tree trucks and bollards. A benefit of this design is that the parking grove not only shades parked cars, but also presents an attractive open space when cars are absent. Examples of parking groves are shown in Figures 3-9 and 3-10. Figure 3-9 Parking Grove Figure 3-10 Parking Grove Overflow Parking 'arking lot design often is required to iccommodated peak demand, generating a ugh proportion of impervious land coverage »f very limited usefulness. An alternative is to lifferentiate between regular and peak tarking demands, and to construct the peak tarking stalls of a different, more permeable, aaterial. This "overflow parking" area can be aade of a turf block, which appears as a green iwn when not occupied by vehicles or rushed stone or other materials. See Figure -17 e same concept can be applied to ( ""/tffith temporary parking needs, such as .urgency access routes, or in residential pplications, RV, or trailer parking. fftm smote pemuebte ettetfow nails (t,g. tarfblixk) Figure 3-1 i Overflows Parking Section 3 Site and Facility Design for Water Quality Protection Porous Pavement Recharge Bed In some cases, parking lots can be designed to perform more complex stormwater management functions. Constructing a stone-filled reservoir below the pavement surface and directing runoff underground by means of perforated distribution pipes can achieve subsurface stormwater storage and infiltration as shown in Figure 3-12. Subsurface infiltration basins eliminate the possibilities of mud, mosquitoes and safety hazards sometimes perceived to be associated with ephemeral surface drainage. They also can provide for storage of large volumes of runoff, and can be incorporated with roof runoff collection systems.Figure 3-12 Porous Pavement Recharge Bed 3.2.3 Driveways Driveways can comprise up to 40% of the total transportation network in a conventional development, with streets, turn-arounds, and sidewalks comprising the remaining 60%. )riveway length is generally determined by garage setback requirements, and width is usually mandated by municipal codes and ordinances. If garages are setback from the street, long driveways are required, unless a rear alley system is included to provide garage access. If parking for two vehicles side by side is required, a 20 ft minimum width is required. Thus, if a 20 ft setback and a two car wide driveway are required, a minimum of 400 ft2 of driveway will result, or 4% of a typical 10,000 ft2 residential lot. If the house itself is compact, and the driveway is long, wide, and paved with an impervious material such as asphalt or concrete, it can become the largest component of impervious land coverage on the lot. Municipalities can reduce the area dedicated to driveways by allowing for tandem parking (one vehicle in front of another on a narrow driveway). Also, if shared driveways are permitted, then two or more garages can be accessed by a single driveway, further reducing required land area. Rear alley access to the garage can reduce driveway length, but overall impervious surface coverage may not be reduced if the alleys are paved with impervious materials and the access streets remain designed to conventional municipal standards. Alternative solutions that work to reduce the impact of water quality problems associated with impervious land coverage on city streets also work on driveways. Sloping the driveway so that it drains onto an adjacent turf or groundcover area prevents driveways from draining directly to storm drain systems. This concept is shown in Figures 3-13 and 3-14. Use of turf-block or unit pavers on sand creates attractive, low maintenance, permeable driveways that filter stormwater. See Figure 3-15. Crushed aggregate can serve as a relatively smooth pavement with minimal aintenance as shown in Figure 3-16. Paving only under wheels (Figure 3-17) is a viable, inexpensive design if the driveway is straight between the garage and the street and repaying temporary parking areas with permeable unit pavers such as brick or stone can significantly reduce the percentage of impervious area devoted to the driveway. Section 3 and Facility Design for Water Quality Protection iSiettfltttvUittrfst- in/iimtta inle tail caMemtmlfJfallutano tarrial to outfall Figure 3-13 Traditional Design Drains Flow Directly to Storm Drain ihittflma tt. ttttf Figure 3-14 Alternative Solution Slopes Flow to Groundcover unitpavm-a»-san4 mubed Figure 3-15 Unit Pavers Figure 3-16 Crushed Aggregate • (awn or groutielcover Figure 3-17 Paving Only Under Wheels Section 3 Site and Facility Design for Water Quality Protection 3.2.4 Landscape and Open Space In the natural landscape, most soils infiltrate a high percentage of rainwater through a complex web of organic and biological activities that build soil porosity and permeability. Roots reach into the soil and separate particles of clay, insects excavate voids in the soil mass, roots decay leaving networks of macro pores, leaves fall and form a mulch over the soil surface, and earthworms burrow and ingest organic detritus to create richer, more porous soil. These are just a few examples of the natural processes that occur within the soil. Maintenance of a healthy soil structure through the practice of retaining or restoring native soils where possible and using soil amendments where appropriate can improve the land's ability to filter and slowly release stormwater into drainage networks. Construction practices such as decreasing soil compaction, storing topsoil on-site for use after construction and chipping wood for mulch as it is cleared for the land can improve soil quality and help maintain healthy watersheds. Practices that reduce erosion and help retain water on-site include incorporating organic amendments into disturbed soils after construction, retaining native vegetation, and covering soil during revegetation. Subtle changes in grading can also improve infiltration. Landscape surfaces are conventionally graded to have a slight convex slope. This causes water to run off a central high point into a surrounding drainage system, creating increased runoff. If a landscape surface is graded to have a slightly concave slope, it will hold water. The infiltration value of concave vegetated surfaces is greater in permeable soils. Soils of heavy clay or underlain with hardpan provide less infiltration value. In these cases concave vegetated surfaces must be designed as retention/detention basins, with proper outlets or under drains to an interconnected system. Multiple Small Basins Biofilters, infiltration, retention/detention basins are the basic elements of a landscape designed for stormwater management. The challenge for designers is to integrate these elements creatively and attractively in the landscape — either within a conventional landscape aesthetic or by presenting a different landscape image that emphasizes the role of water and drainage. Multiple small basins can provide a great deal of water storage and infiltration capacity. These small basins can fit into the parkway planting strip or shoulders of street rights-of-way. If connected by culverts under walks and driveways, they can create a continuous linear infiltration system. Infiltration and retention/detention basins can be placed under wood decks, in parking lot planter islands, and at roof downspouts. Outdoor patios or seating.areas can be sunken a few steps, paved with a permeable pavement such as flagstone or gravel, and designed to hold a few inches of water collected from surrounding rooftops or paved areas for a few hours after a rain. -All of these are examples of small basins that can store water for a brief period, allowing it to Wtifiltrate into the soil, slowing its release into the drainage network, and filtering pollutants. An ordinary lawn can be designed to hold a few inches of water for a few hours after a storm, attracting birds and creating a landscape of diversity. Grass/ vegetated swales can be integrated with landscaping, providing an attractive, low maintenance, linear biofilter. Extended detention (dry ponds) store water during storms, holding runoff to predevelopment levels. Pollutants Section 3 , -"* and Facility Design for Water Quality Protection1 W settle and are removed from the water column before discharging to streams. Wet ponds serve a similar purpose and can increase property values by providing a significant aesthetic, and passive recreation opportunity. Plant species selection is critical for proper functioning of infiltration areas. Proper selection of plant materials can improve the infiltration potential of landscape areas. Deep-rooted plants help to build soil porosity. Plant leaf-surface area helps to collect rainwater before it lands on the soil, especially in light rains, increasing the overall water-holding potential of the landscape. A large number of plant species will survive moist soils or periodic inundation. These plants provide a wide range of choices for planted infiltration/detention basins and drainage swales. Most inundated plants have a higher survival potential on well-drained alluvial soils than on fine textured shallow soils or clays. Maintenance Needs for Stormwater Systems All landscape treatments require maintenance. Landscapes designed to perform stormwater management functions are not necessarily more maintenance intensive than highly manicured conventional landscapes. A concave lawn requires the same mowing, fertilizing and weeding as a convex one and often less irrigation because more rain is filtered into the underlying soil. Sr 'lines infiltration basins may require a different kind of maintenance than conventionally Typical maintenance activities include periodic inspection of surface drainage systems to ensure clear flow lines, repair of eroded surfaces, adjustment or repair of drainage structures, soil cultivation or aeration, care of plant materials, replacement of dead plants, replenishment of mulch cover, irrigation, fertilizing, pruning and mowing. Also, dead or stressed vegetation may indicate chemical dumping. Careful observation should be made of these areas to determine if such a problem exists. Landscape maintenance can have a significant impact on soil permeability and its ability to support plant growth. Most plants concentrate the majority of their small absorbing roots in the upper 6 in. of the soil surface if a mulch or forest litter protects the surface. If the soil is exposed or bare, it can become so hot that surface roots will not grow in the upper 8 to 10 in. The common practice of removing all leaf litter and detritus with leaf blowers creates a hard-crusted soil surface of low permeability and high heat conduction. Proper mulching of the soil surface improves water retention and infiltration, while protecting the surface root zone from temperature extremes. 'n addition to impacting permeability, landscape maintenance practices can have adverse effects >n water quality. Because commonly used fertilizers and herbicides are a source of organic :ompounds, it is important to keep these practices to a minimum, and prevent over watering. Y*' ^eU maintained and designed, landscaped concave surfaces, infiltration basins, swales ^loretention areas can add aesthetic value while providing the framework for nvironmentally sound, comprehensive stormwater management systems. Section 3 Site and Facility Design for Water Quality Protection Street Trees Trees improve water quality by intercepting and storing rainfall on leaves and branch surfaces, thereby reducing runoff volumes and delaying the onset of peak flows. A single street tree can have a total leaf surface area of several hundred to several thousand ft2, depending on species and size. This aboveground surface area created by trees and other plants greatly contributes to the water holding capacity of the land. They attenuate conveyance by increasing the soil's capacity to filter rainwater and reduce overland flow rates. By diminishing the impact of raindrops on unvegetated soil, trees reduce soil erosion. Street trees also have the ability to reduce ambient temperature of stormwater runoff and absorb surface water pollutants. When using street trees to achieve stormwater management goals, it is important to use tree species with wide canopies. Street tree design criteria should specify species expected to attain 20 to 30 ft canopies at maturity. Planter strips with adequate width and depth of soil volume are necessary to ensure tree vitality and reduce future maintenance. Structural soils also provide rooting space for large trees and can be specified along narrow planter strips and underneath sidewalks to enable continuous belowground soil and root connections. 3.2.5 Outdoor Work Areas lie site design and landscape details listed in previous sections are appropriate for uses where Srow concentrations of pollutants can be mitigated through infiltration, retention and detention. Often in commercial and industrial sites, there are outdoor work areas in which a higher concentration of pollutants exists, and thus a higher potential of pollutants infiltrating the soil. These work areas often involve automobiles, equipment machinery, or other commercial and industrial uses, and require special consideration. Outdoor work areas are usually isolated elements in a larger development. Infiltration and detention strategies are still appropriate for and can be applied to other areas of the site, such as parking lots, landscape areas, employee use areas, and bicycle path. It is only the outdoor work area within the development - such as the loading dock, fueling area, or equipment wash area - that requires a different drainage approach. This drainage approach is often precisely the opposite from the infiltration/detention strategy — in other words, collect and convey. In these outdoor work areas, infiltration is discouraged and runoff is often routed directly to the sanitary sewer, not the storm drain. Because this runoff is being added to the loads normally received by the water treatment plants (publicly owned treatment works - POTWs), it raises several concerns that must be addressed in the planning and design stage. These include: • Higher flows that could exceed the sewer system capacity • Catastrophic spills that may cause harm to POTW operation A potential increase in pollutants These concerns can be addressed at policy, management, and site planning levels. / , *fjg ancj pacility Design for Water Quality Protection Policy Piping runoff and process water from outdoor work areas directly to the sanitary sewer for treatment by a downstream POTW displaces the problem of reducing stormwater pollution. Municipal stormwater programs and/or private developers can work with the local POTW to develop solutions that minimize effects on the treatment facility. It should be noted that many POTWs have traditionally prohibited the discharge of stormwater to their systems. However, these prohibitions are being reviewed in light of the benefits possible from such diversions. Management Commercial and industrial sites that host special activities need to implement a pollution prevention program minimizing hazardous material use and waste. For example, if restaurant grease traps are directly connected to the sanitary sewer, proper management programs can mitigate the amount of grease that escapes from the trap, clogging sewer systems and causing overflows or damage to downstream systems. Site Planning Outdoor work areas can be designed in particular ways to reduce their impacts on both stormwater quality and sewage treatment plants. Create an impermeable surface such as concrete or asphalt, or a prefabricated metal drip pan, depending on the use. • Cover the area with a roof. This prevents rain from falling on the work area and becoming polluted runoff. • Berm or mound around the perimeter of the area to prevent water from adjacent areas to flow on to the surface of the work area. • Directly connect runoff. Unlike other areas, runoff from these work areas is directly connected to the sanitary sewer or other specialized containment systems. This allows the more highly concentrated pollutants from these areas to receive special treatment that removes particular constituents. Approval for this connection must be obtained from the appropriate sanitary sewer agency. • Locate the work area away from storm drains or catch basins. If the work area is adjacent to, or directly upstream from a storm drain or landscape drainage feature (e.g., bioswales), debris or liquids from the work area can migrate into the stormwater system. • Plan the work area to prevent run-on. This can be accomplished by raising the work area or by diverting run-on around the work area. ^ "?e design elements are general considerations for work areas. In designing any outdoor e area, evaluate local ordinances affecting the type of work area, as many local jurisdictions specific requirements. Some activities are common to many commercial and industrial sites. These include garbage and recycling, maintenance and storage, and loading. These activities can have a significant Section 3 Site and Facility Design for Water Quality Protection negative impact on stormwater quality, and require special attention to the siting and design of the activity area. 3.2,6 Maintenance and Storage Areas To reduce the possibility of contact with stormwater runoff, maintenance and storage areas can be sited away from drainage paths and waterways, and covered. Implementing a regular maintenance plan for sweeping, litter control, and spill cleanup also helps prevent stormwater pollution. Specifying impermeable surfaces for vehicle and equipment maintenance areas will reduce the chance of pollutant infiltration. A concrete surface will usually last much longer than an asphalt one, as vehicle fluids can either dissolve asphalt or be absorbed by the asphalt and released later. See Figure 3-18. Figure 3-18 Material Storage 3.2.7 Vehicle and Equipment Washing Areas It is generally advisable to cover areas used for regular washing of vehicles, trucks, or equipment, surround them with a perimeter berm, and clearly mark them as a designated washing area. Sumps or drain lines can be installed to collect wash water, which may be treated for reuse or recycling, or for discharge to the sanitary sewer. The POTW may require some form of pretreatment, such as a trap, for these areas. Fueling and maintenance activities must be isolated from the vehicle washing facilities. These activities have specific requirements, described later in this section. Storage of bulk materials, fuels, oils, solvents, other chemicals, and process equipment should be accommodated on an impervious surface covered with a roof. To reduce the chances of corrosion, materials should not be stored directly on the ground, but supported by a wire mesh or other flooring above the impervious pavement. In uncovered areas, drums or other containers can be stored at a slight angle to prevent ponding of rainwater from rusting the lids. Liquid containers should be stored in a designated impervious area that is roofed, fenced within a berm, to prevent spills from flowing into the '•'•••• storm drain. If hazardous materials are being used or stored, additional specific local, state or federal requirements may apply. 3=2.8 Loading Area Loading areas and docks can be designed with a roof or overhang, and a surrounding curb or berm. See Figure 3-19. The area should be graded to direct flow toward an inlet with a shutoff valve or dead-end sump. The sump must be designed with enough capacity to hold a spill while the valve is closed. If the sump has a valve, it must be kept in the closed position and require an 3 Facility Design for Water Quality Protection action to open it, All sumps must have a sealed bottom so they cannot infiltrate water. Contaminated accumulated waste and liquid must not be discharged to a storm drain and may be discharged to the sanitary sewer only with the POTW's permission. If the waste is not approved for discharge to the sanitary sewer, it must be conveyed to a hazardous waste (or other offsite disposal) facility, and may require pretreatment. Some specific uses have unique requirements. 3.2.9 Trash Storage Areas Areas designated for trash storage can be covered to protect containers from rainfall. Where covering the trash storage area is not feasible, the area can be protected from run on using grading and berms, and connected to the sanitary sewer to prevent leaks from leaving the designated trash storage area enclosure. 3.2.10 Wash Areas Areas designated for washing of floor mats, containers, exhaust filters, and similar items can be covered md enclosed to protect the area from rainfall and from overspray leaving the area. These areas can also je connected to the sanitary sewer to prevent wash waters from leaving the designated enclosures. A jenefit of covering and enclosing these areas is that vectors may be reduced and aesthetics of the area our' d. ..11 Fueling Areas n all vehicle and equipment fueling areas, plans must be developed for cleaning near fuel lispensers, emergency spill cleanup, and routine inspections to prevent leaks and ensure iroperly functioning equipment. f the fueling activities are minor, fueling can be performed in a designated, covered and bermed rea that will not allow run-on of stormwater or runoff of spills. .etail gasoline outlets and vehicle fueling areas have specific design guidelines. These are escribed in a Best Management Practice Guide for retail gasoline outlets developed by the alifornia Stormwater Quality Task Force, in cooperation with major gasoline corporations. The ractice guide addresses standards for existing, new, or substantially remodeled facilities. In idition, some municipal stormwater permits require RGOs to provide appropriate runoff eatment. iel dispensing areas are defined as extending 6.5 ft from the corner of each fuel dispenser or ie length at which the hose and nozzle assembly may be operated plus i ft, whichever is less. aese areas must be paved with smooth impervious surfaces, such a Portland cement concrete, ith a 2-4% slope to prevent ponding, and must be covered. The cover must not drain onto the ork area. The rest of the site must separate the fuel dispensing area by a grade break that •eve1*** run-on of stormwater. -* the gas station, the outdoor trash receptacle area (garbage and recycling), and the r/water supply area must be paved and graded to prevent stormwater run-on. Trash ceptacles should be covered. Attachment 10 Attachment 10 Source Control BMPs The following Source Control BMPs are to be used in this project: SD-10 Site Design and Landscape Planning SD-11 Roof Runoff Controls SD-12 Efficient Irrigation SD-13 Storm Drain System Signs SD-32 Trash Enclosures Source Control BMP Fact Sheets can be individually downloaded from the California Stormwater BMP Handbook website at www.cabmphandbooks.com. Attachment 11 Attachment 11 Treatment Control BMPs The following Treatment Control BMPs are to be used in this project: TC-22 Extended Detention Basin TC-30 Vegetated Swale TC-60 Multiple Systems MP-52 Drain Inserts Treatment Control BMP Fact Sheets can be individually downloaded from the California Stormwater BMP Handbook website at www.cabmphandbooks.com. Attachment 12 Curb Inlet Filter Sizing Calculations The curb inlet filter being utilized for this project is the "California Curb Shelf Basket Water Cleansing System" by Suntree Technologies. (See Attachment 13) Per the manufacturer's specifications, each 3' basket is capable of handling 10.6 cfs. Both of the curb inlets along Glen Ave. have flows less than 10.6 cfs. Therefore, all curb inlet filters will adequately handle 100- year flows. 11 G:\011014\SWMP\PA 14\SWMP 2 .doc Attachment 13 'The California Curb Shelf Basket Water Cleansing System By: Suntree Technologies Inc. - (321) 637-7552 www.suntreetech.com San Diego regional standard Curb Inlet - Type B Figure 1 Figure 3 Patent Pending Z-mold Drive Pin .-.•-•..•-•.•.••:-v Catch Basin Wall Details of Z-mold Figure 2 FLOW RATES per 3 ft BASKET Q = SO*cd*A,/2*g*h od=0SS55.0'= .67 Top Front Bottom Front Bottom TOTAL SO .62 .56 .68 A (ft2) 65.1 179.4 165.9 h(ft) 7.9 12.40 16.0 Q(*') 1.6 3.8 5.1 10.6 NOTES: 1. Shelf system provides for entire coverage of inlet opening so to divert a« flow to basket. 2. Shelf system manufactured from marine grade fiberglass, gel coated for UV protection. 3. Shelf system attched to catch basin with non corrosive hardware. 4. Filtration Basket structure manufactured of marine grade fiberglass, gel coated for UV protection. 5. Filtration Basket fine screen and coarse containment screen manufactured from stainless steal. 6. nitration Basket holds boom of absorbent media to capture hydrocarbons. Boom is easily replaced without removing mounting hardware. 7. Filtration Basket location Is directly under manhole access for easy maintenance. Distributed by: BIO CLEAN ENVIRONMENTAL SERVICES INC. PO BOX 869, OCEANSIDE, CA 92049 •7OIA CTA\/ California Curb Shelf Basket Water Cleansing System By: Suntree Technologies Inc. - (321) 637-7552 www.suntreetech.com The California Curb Shelf Basket Water Cleaning System Figure 1 San Diego regional standard Curb Inlet - Type C gure3 Patent Pending Catch Basin Wan Details of Shelf System (Dimensions will vary) Figure 2 FLOW RATES per 3 ft BASKET Q = SO * cd*A,/2*g*n cd =°SS*S.'I'= .67 Top Front Bottom Front Bottom TOTAL SO .62 .66 .68 A (ft2) 85.1 179.4 165.9 h(B) 7.9 12.40 18.0 Q<£) 1.6 3.8 5.1 10.6 NOTES: 1. Shelf system provides for entire coverage of inlet opening so to divert all flow to basket 2. Shelf system manufactured from marine grade fiberglass, gel coated for UV protection. 3. Shelf system attched to catch basin with non corrosive hardware. 4. Filtration Basket structure manufactured of marble grade fiberglass, gel coated for UV protection. 5. Filtration Basket fine screen and coarse containment screen manufactured from stainless steel. 6. Filtration Basket holds boom of absorbent media to capture hydrocarbons. Boom Is easily replaced without removing mounting hardware. 7. Filtration Basket location Is directly under grate for easy maintenance. Distributed by: BIO CLEAN ENVIRONMENTAL SERVICES INC. PO BOX 869, OCEANSIDE, CA 92048 /-rcf\\ Attachment 14 OP £eP0E-T ONl p HYDROLOGIC AND HYDRAULIC ANALYSES FOR ROBERTSON'S RANCH EAST VILLAGE September 2,2004 JjJLJclXJLJUUQ. CMI Engineering ° Hydrology ° Hydraulics <• Sedimentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (858) 692-0760 Attachment 15 HYDRAULIC ANALYSIS FOR 84" RCP AT ROBERTSON'S RANCH EAST VILLAGE November 22, 2004 Chang Civil Engineering ° Hydrology ° Hydraulics • Sedimentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (858) 692-0760 Attachment 16 PRELIMINARY STORM WATER MANAGEMENT PLAN For ROBERTSON RANCH EAST VILLAGE C.T. 02-16 M.P. 02-03 Revised: November 30,2006 Revised: June 26, 2006 Revised: September 2,2005 Revised: August 16, 2005 Revised: July 12, 2005 Revised: September 16,2004 Prepared: Aprils, 2004 JN 01-1014/5 Prepared By: O'DAY CONSULTANTS 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92008 Keith Hansen RCE 60223 Date 1 G:\011014\SWMP\SWMP-EAST-REV-5.doc Vegetated Swale South of Cannon Rd. (Flow-based BMP) 1= 0.2 in/hr A= 4Q0.70 AC." Q=CIA Q= (.56)(0.2)(1 08.78)= 12.18 cfs c Tributary Area to Vegetated Swale Clv8Cal Basin Subbasin Area (AC.) CIV0 Calculations B C D E F H B-1 B-2 B-3 C-1 C-2 E-1 E-2 E-3 F-1 F-2 •939- V B& 16.21 38.05 2.63 3.68 28.58 1.41 1.61 0.5 2.99 5.9 3.63 0.71 0.35 0.57 0.57 0.63 0.57 0.87 0.87 0.87 0.71 0.63 0.57 Total 108.78 Cawa= 0.56 V.-- o O'Day Consultants Inc. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92008 Tel: (760) 931-7700 Fax: (760) 931-8680 Inside Diameter ( 24.00 in.) * - C- ' •V^'* * 67 t £,A . U> - /' V * i / /^ --10 * Water * | * * j I * * ( 15.16 in.) ( 1.264 ft.) * * I | v Circular Channel Section Plowrate 12.180 CFS Velocity 5.823 fps Pipe Diameter 24.000 inches Depth of Flow 15.165 inches Depth of Flow 1.264 feet Critical Depth . 1.259 feet Depth/Diameter (D/d) 0.632 Slope of Pipe 0.550 % X-Sectional Area 2.092 sq. ft. Wetted Perimeter 3.675 feet ARA(2/3) 1.437 Mannings ' n' 0.013 Min. Fric. Slope, 24 inch Pipe Flowing Full 0.290 % O r/c'i.t_:- j'' pe. per r-A • / O'Day Consultants, Inc. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92008 Tel: 760-931-7700 Fax: 760-931-8680 Inside Diameter ( 24.00 in.) Water * ( 15.24 in.) ( 1.270 ft.) v Circular Channel Section (D/d) Flowrate Velocity Pipe Diameter . Depth of Flow . Depth of Flow . Critical Depth Depth/Diameter Slope of Pipe X-Sectional Area Wetted Perimeter ARA{2/3) Mannings 'n1 Min. Fric. Slope, 24 inch Pipe Flowing Full 12.270 5.831 24.000 15.241 1.270 1.255 0.635 0.550 2.104 3.689 1.448 CFS fps inches inches feet feet sq. ft. feet 0.013 0.294 O'Day Consultants Inc. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92008 Tel: (760) 931-7700 Fax: (760) 931-8680 ****** ****** *** *** *** *** *** *** *** |< -( 41.34')--- - >| *** ^ g>33i)AiAXAX*AA*** *** *** *** *** *** *** ***]< ( 40.00') >|*** ************************s' ******************** Trapezoidal Channel f\ _ ',_, ~~>~7 ,CV ~*~ / ^-- ' --- / • Flowrate 12.180 CFS Velocity 0.894 fps Depth of Flow 0.335 feet Critical Depth 0.139 feet Freeboard 0.000 feet Total Depth 0.335 feet Width at Water Surface .... 41.340 feet Top Width 41.340 feet Slope of Channel 0.400 % Left Side Slope 2.000 : 1 Right Side Slope 2.000 : 1 Base Width 40.000 feet X-Sectional Area 13.622 sq. ft. Wetted Perimeter 41.498 feet AR*(2/3) 6.482 Mannings 'n' 0.050 \ i ').'""> 4 .-> 1Kcr> o t h c> O'Day Consultants, Inc. 2710 Loker Avenue West, Suite 100 Carlsbad, CA 92008 Tel: 760-931-7700 Fax: 760-931-8680 *************** ****** ********* *** |< ......... ---- ( 41.35') -------------- ****AAAA^A Water Depth ( 0.34 ' ) ******* *** *** *** *** *** *** ***[< ----- ( 40.00') ---- >]*** ************************ ******************** Trapezoidal Channel Flowrate ........... ....... 12 . 270 CFS Velocity .................. 0 . 897 fps Depth of Flow ............. 0 . 336 feet Critical Depth ............ 0.140 feet Freeboard ................. 0 . 000 feet Total Depth ...... ......... 0 .336 feet Width at Water Surface .... 41.345 feet Top Width ................. 41 . 345 feet Slope of Channel .......... 0 .400 % Left Side Slope ........... 2 . 000 : 1 Right Side Slope .......... 2.000 : 1 Base Width ................ 40 . 000 feet X-Sectional Area .......... 13.677 sq. ft Wetted Perimeter .......... 41.504 feet ARA(2/3) .................. 6.525 Mannings 'n' .............. 0.050 *** (PT f(Cf r*****Ar **************************** ****** pIPE FLow CALCULATIONS ****** Copyright (c) 1988, CivilDesign Software, Inc. **** PRESSURE FLOW CALCULATIONS **** CALCULATE PIPE CAPACITY GIVEN: Channel Slope = -.005412 (Ft./Ft.) Invert elevation at pipe INLET = Invert elevation at pipe OUTLET = Length of pipe = 182.930 (Ft.) Given Flow Rate = .00 Cubic Feet/Second Not including elevation change, the Pressure difference (Outlet - Inlet) = 6.500 Feet of H2O -.5412 % 40.840 (Ft.) 39.850 (Ft.) *** pipe PRESSURE FLOW *** Mannings "n" = .013 Minor friction loss "K" factor = 1.50 PIPEFLOW RESULTS: No. of pipes = 1 Length of pipe(s) = Velocity = 10.54 (Ft/S) Given pressure difference (Outlet - Inlet) 182.93 (Ft.) TOTAL pipe flow Given pipe size 33.11 (CFS) .1486E+05 (GPM) 21.40 (MGD) 24.00 (In.) 6.500 (Ft.H20) 2.818 (PSI) Elevation change inlet to outlet = TOTAL pressure required at pipe inlet Head loss due to pipe friction = II II It tt H II = Head loss due to minor factorsit n H n n n Combined pipe losses = 6.500 " » " = 2.818 Individual pipe flow 3.912 1.696 2.588 1.122 -.990 (Ft.) 5.510 (Ft H2O) 2.389 (PSI) (Ft H2O) (PSI) (Ft H2O) (PSI) 33.11 . 1486E+05 21.40 (Ft H20) (PSI) (CFS) (GPM) (MGD) Page 1 of 1 Attachment 17 STORM WATER STANDARDS Development Serv,ces O I MIM UMf\UO Engineering Department CITY OF QUESTIONNAIRE 1635 Faraday Avenue 760-602-2750 www.carlsbadca.govV' V-AKLibAU E-34 INSTRUCTIONS: This questionnaire must be completed by applicant in advance of submitting for a development application (subdivision and land use planning approvals and construction permits). The results of the questionnaire determine the level of storm water pollution prevention standards applied to a proposed development or redevelopment project. Many aspects of project site design are dependent upon the storm water pollution protection standards applied to a project. Applicant responses to the questionnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibility for making the final assessment after submission of the development application. A staff determination that the development application is subject to more stringent storm water standards than initially assessed by the applicant, will result in the return of the development application as incomplete. If applicants are unsure about the meaning of a question or need help in determining how to respond to one or more of the questions, they are advised to seek assistance from Engineering Department Development Services staff. A separate completed and signed questionnaire must be submitted for each new development application submission. Only one completed and signed questionnaire is required when multiple development applications for the same project are submitted concurrently. In addition to this questionnaire, applicants for construction permits must also complete, sign and submit a Construction Activity Storm Water Standards Questionnaire. To address pollutants that may be generated from new development, the city requires that new development and significant redevelopment priority projects incorporate Permanent Storm Water Best Management Practices (BMPs) into the project design, which are described in Section 2 of the city's Storm Water Standards Manual This questionnaire should be used to categorize new development and significant redevelopment projects as priority or non-priority, to determine what level of storm water standards are required or if the project is exempt. \1. Is your project a significant redevelopment? Definition: Significant redevelopment is defined as the creation or addition of at least 5,000 square feet of impervious surface on an already developed site. Significant redevelopment includes, but is not limited to: the expansion of a building footprint; addition to or replacement of a structure; structural development including an increase in gross floor area and/or exterior construction remodeling; replacement of an impervious surface that is not part of a routine maintenance activity; and land disturbing activities related with structural or impervious surfaces. Replacement of impervious surfaces includes any activity that is not part of a routine maintenance activity where impervious material(s) are removed, exposing underlying soil during construction. Note: If the Significant Redevelopment results in an increase of less than fifty percent of the impervious surfaces of a previously existing development, and the existing development was not subject to SUSMP requirements, the numeric sizing criteria discussed in Section F.1 .b. (2)(c) applies only to the addition, and not to the entire development. 2. If your project IS considered significant redevelopment, then please skip Section 1 and proceed with Section 2. 3. If your project IS NOT considered significant redevelopment, then please proceed to Section 1. E-34 Page 1 of 3 REV 8/12/09 CITY OF CARLSBAD STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Engineering Department 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov SECTION 1 NEW DEVELOPMENT PRIORITY PROJECT TYPE Does you project meet one or more of the following criteria: 1. Home subdivision of 100 units or more. Includes SFD, MFD, Condominium and Apartments 2. Residential development of 10 units or more. Includes SFD, MFD, Condominium and Apartments 3. Commercial and industrial development areater than 100,000 sauare feet including parking areas. Any development on private land that is not for heavy industrial or residential uses. Example: Hospitals, Hotels, Recreational Facilities, Shopping Malls, etc. 4. • Heavy Industrial /Industry -greater than 1 acre (NEED SIC CODES FOR PERMIT BUSINESS TYPES) SIC codes 5013, 5014, 5541, 7532-7534, and 7536-7539 5. Automotive repair shoo. SIC codes 5013, 5014, 5541 , 7532-7534, and 7536-7539 6. A New Restaurant where the land area of development is 5.000 sauare feet or more includina parking areas. SIC code 5812 7. Hillside development (1) greater than 5,000 square feet of impervious surface area and (2) development will grade on any natural slope that is 25% or greater 8. Environmentally Sensitive Area (ESA). Impervious surface of 2,500 square feet or more located within, "directly adjacent"2 to (within 200 feet), or "discharging directly to"3 receiving water within the ESA1 9. Parking lot. Area of 5,000 square feet or more, or with 15 or more parking spaces, and potentially exposed to urban runoff 10. Retail Gasoline Outlets - serv/no more than 100 vehicles perdav. Serving more than 100 vehicles per day and greater than 5,000 square feet 11. Streets, roads, highways, and freeways. Project would create a new paved surface that is 5,000 square feet or greater. 12. Coastal Development Zone. Within 200 feet of the Pacific Ocean and (1 ) creates more than 2500 square feet of impermeable surface or (2) increases impermeable surface on property by more than 10%. YES X X NO X X X -x X .x xT .,"X-" •^ X 1 ESA (Environmentally Sensitive Areas) include but are not limited to all Clean Water Act Section 303(d) impaired water bodies; areas designated as Areas of Special Biological Significance by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); water bodies designated with the RARE beneficial use by the State Water Resources Control Board (Water Quality Control Plan for the San Diego Basin (1994) and amendments); areas designated as preserves or their equivalent under the Multi Species Conservation Program within the Cities and County of San Diego; and any other equivalent environmentally sensitive areas which have been identified by the co-permittees. 2 "Directly adjacent" means situated within 200 feet of the environmentally sensitive area. 3 "Discharging directly to" means outflow from a drainage conveyance system that is composed entirely of flows from the subject development or redevelopment site, and not commingled with flow from adjacent lands. Section 1 Results: If you answered YES to ANY of the questions above you have a PRIORITY project and PRIORITY project requirements DO apply. A Storm Water Management Plan, prepared in accordance with City Storm Water Standards, must be submitted at time of application. Please check the "MEETS PRIORITY REQUIREMENTS" box in Section 3. If you answered NO to ALL of the questions above, then you are a NON-PRIORITY project and STANDARD requirements apply. Please check the "DOES NOT MEET PRIORITY REQUIREMENTS" box in Section 3. E-34 Page 2 of 3 REV 8/12/09 t ^^ CITY OF CARLSBAD STORM WATER STANDARDS QUESTIONNAIRE E-34 Development Services Engineering Department 1635 Faraday Avenue 760-602-2750 www.carlsbadca.gov SECTION 2 SIGNIFICANT REDEVELOPMENT:YES NO 1. If the existing development was constructed today, would it qualify as a priority project? (Priority projects are defined in Section 1) If you answered YES, please proceed to question 2. If you answered NO, then you ARE NOT a significant redevelopment and you ARE NOT subject to PRIORITY project requirements, only STANDARD requirements. Please check the "DOES NOT MEET PRIORITY REQUIREMENTS" box in Section 3 below. 2.Is the project solely limited to one of the following: a. Trenching and resurfacing associated with utility work? b. Resurfacing and reconfiguring existing surface parking lots? c. New sidewalk construction, pedestrian ramps, or bike lane on public and/or private existing roads? d. Replacement of existing damaged pavement? If you answered NO to ALL of the questions, then proceed to Question 3. If you answered YES to ONE OR MORE of the questions then you ARE NOT a significant redevelopment and you ARE NOT subject to PRIORITY project requirements, only STANDARD requirements. Please check the "DOES NOT MEET PRIORITY REQUIREMENTS" box in Section 3 below. Will the development create, replace, or add at least 5,000 square feet of impervious surfaces on an existing development, or be located within 200 feet of the Pacific Ocean and (1) create more than 2500 square feet of impermeable surface or (2) increase impermeable surface on property by more than 10%?X If you answered YES, you ARE a significant redevelopment and you ARE subject to PRIORITY project requirements. Please check the "MEETS WITH REQUIREMENTS" box in Section 3 below. If you answered NO, you ARE NOT a significant redevelopment, and you ARE NOT subject to PRIORITY project requirements, only STANDARD requirements. Please check the 'DOES NOT MEET PRIORITY REQUIREMENTS" box in Section 3 below. SECTION 3 Questionnaire Results: ;gL MY PROJECT MEETS PRIORITY REQUIREMENTS. MUST COMPLY WITH PRIORITY PROJECT STANDARDS AND MUST PREPARE A STORM WATER MANAGEMENT PLAN FOR SUBMITTAL AT TIME OF APPLICATION. D MY PROJECT DOES NOT MEET PRIORITY REQUIREMENTS AND MUST ONLY COMPLY WITH STANDARD STORM WATER REQUIREMENTS. Applicant Information and Signature Box Address: ; Assessor's Parcel Number(s): 6. it'rt ;i ft /- >;'. <:<:/ / A'f • / /V^'/ it- 3 •• o clp • V 7 " ^ ^ Applicant Name: A ,x;:v,; ••/, / »^v // /-/'<•'"' Applicant Signature:/ Applicant Title: Date: 0(^6, 2.OO f This Box for City Use Only City Concurrence:Yes No By: Date: Project ID: E-34 Page 3 of 3 REV 8/12/09