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HomeMy WebLinkAboutCT 12-03; 201 Walnut Townhomes; Major Swamp; 2014-10-03201 Walnut Townhomes Stormwater Management Plan (Major SWMP) For 201 WALNUT TOWNHOMES CT 12-03 SWMP 14-08 Preparation/Revision Date: October 3, 2014 Prepared for: 201 Walnut, LLC 17828 Villamoura Drive Poway, CA 92064 Prepared by: Brian Ardolino, Project Engineer Pasco Laret Suiter & Associates 535 N. liighway 101, Suite A Solana Beacli, CA 92075 858.259.8212 The selection, sizing, and preUminary design of stormwater treatment and other control measures in this plan have been prepared under the direction of the foUowing Registered Civil Engineer and meet the requirements of Regional Water Quality Control Board Order R9-2007-0001 and subsequent amendments. Brian Ardolino. RCE 71651 Date SWMP-October 2014 201 Walnut Townhomes SECTION I PROJECT SETTING Ptoject Name: 201 Walnut Townhomes Address: 201 Walnut Ave Carlsbad, CA 92008 V"" «: r<,» i.-.f:'.i • I "5- Not to Scale TABLE 1: PROJECT DESCRIPTION 1. Please provide a brief description of the project. This project proposes to demoHsh an existing residence, and construct a 14-unit attached townhome complex with associated landscaping and hardscape improvements. As well as frontage improvements along Garfield Street, Walnut Avenue and Lincoln Street. In order to address Treatment Control criteeria and meet Hydromodification criteria, the proposed development was divided into six Drainage Management' Area Basins and Bioretention was chosen as the method of treatment and stormwater storage. SWMP-October 2014 201 Walnut Townhomes Per the DMA Exhibit in Section IX, the BMP areas were sized were sized to 4% of the resultant area for Minimum Treatment Control BMP Area and 7% of the resultant area for Minimum Area for Hydromodification and Flow Control. The results of those calculations are as follows: Min Treatment Area Min Area for HMP Proposed BMP Area BMP 1 157 sf 131 sf 160 sf BMP 2 324 sf 567 sf 580 sf BMP 3 35 sf 62 sf 74 sf BMP 4 30 sf 53 sf 54 sf BMP 5 58 sf 101 sf 108 sf BMP 6 215 sf 376 sf 405 sf Per the Sizing Calculations in Section VII, the BMP areas were sized were sized to 7% of the resultant area for Minimum Area for Hydromodification and Flow Control. The results of those calculations are as follows: Min Treatment Area Min Area for HMP Proposed BMP Area BMP 1 N/A. 143 sf 160 sf BMP 2 N/A 550 sf 580 sf BMP 3 N/A 67 sf 74 sf BMP 4 N/A 53 sf 54 sf BMPS N/A 93 sf 108 sf BMP 6 N/A 372 sf 405 sf The proposed Bioretention BMP areas have been sized based on the nainimum HMP requirement or TCBMP requirement, wliichever requirement is larger. The Bioretention BMA areas are not required to provide crushed rock storage below the "Engineered Soil" section due to the Type "A" soil found on site. As a result, we are utilizing the crushed rock storage layer as a means to mitigate peak flow rates and the increase in runoff due to the proposed development. Per the rational method hydrograph data provided in the Hydrology Study dated October 3, 2014, the increase in stormwater volume onsite as a result in the iacrease in runoff is approximately 890 cf. We are proposing 1381 square feet of bioretention. 20" of crushed rock of the bioretention section is reserved for storage for the increase in peak flows. The void ration of the crushed rock is assumed to be 40%. 1,381 sf * 20" * 1V12" * 40% = 921 cf of stormwater storage The proposed storage volume of 920 cf will properly mitigate the increase in stormwater runoff due to the development. SWMP-October 2014 201 Walnut Townhomes 2. Describe the current and proposed zoning and land use designation. The current and proposed zoning and land use designation for the project site is R-3/ BAOZ and a general plan designation of RH 3. Describe the pre-project and post-project topography of the project. (Show on Plan) The existing site has varied topography with elevation ranging from an elevation of approximately 62 feet on the high point at the most southwesterly portion of the site, to approximately 53 feet at the easterly portion of the site. The existing site consists of undeveloped gentiy roUing hill covered by natural vegetation, as well as a single family residence. In the proposed condition, the site foUows the same drainage pattem overaU, flowing from west to east on the property. 4. Describe the soil classification, permeabiUty, erodibiUty, and depth to groundwater for LID and Treatment BMP consideration. (Show on Plan) If infiltration BMPs are proposed, a Geotechnical Engineer must certify infiltration BMPs in Attachment E. The soil classification onsite is TuB per the Soils Survey prepared by the USDA. The Hydrologic Group of this soil type is "A". This soil type is highly permeable. The erodibility of the project site is 1.43 tons/ acre/ year per the RUSLE equation. There are no known "High Risk Areas" that could potentiaUy affect domestic water supply reservoirs or groundwater percolation faciUties within the project area. 5. Describe if contaminated or hazardous soils are within the project area. (Show on Plan) There are no known hazardous or contaminated soils within the project area. 6. Describe the existing site drainage and natural hydrologic features. (Show on Plan). Drainage of the existing site is conveyed via sheet flow from the westerly portion of the site to the easterly portion of the site and discharges onto Lincoln Street. It is then conveyed via gutter west along Walnut Avenue and ultimately discharges onto the train tracks at the end of Walnut Avenue. 7. Describe site features and conditions that constrain, or provide opportunities for stormwater control, such as LID features. The project is designed to minimize the use of impervious areas. Driveway areas have been designed to meet the minimum widths and incorporate permeable pavers. Landscaping areas are incorporated into the plans. The landscaping wUl consist of both native and non-native plants. The goal is to achieve plant estabUshment expeditiously to reduce erosion. The irrigation system for these landscaped areas wUl be monitored to reduce over irrigation. Lawn areas, natural vegetation and bioretention areas are proposed to reduce runoff and maximize infUtration. Is this project within the environmentaUy sensitive areas as defined on the maps in Appendix A of the County of San Diego Standard Urban Storm Water Mitigation Plan for l^nd Development and Public Improvement Projects? Yes I k 9. Is this an emergency project? If yes, please provide a description_below Yes I SWMP-October 2014 201 Walnut Townhomes TABLE 2: CHANNEL& DRAINAGE ANALYSIS No. CRITERIA YES NO N/A COMMENTS 1. WiU the project include work in channels? V IfYESgoto2 IfNOgoto 13. 2. WUl the project iacrease velocity or volume of downstream flow? IfYESgoto6. 3. WUl the project discharge to unHned channels? IfYESgoto. 6. 4. WUl the project increase potential sediment load of downstream flow? If YES go to 6. 5. WUl the project encroach, cross, realign, or cause other hydraulic changes to a stream that may affect downstream channel StabUity? IfYESgoto 8. 6. Review channel lining materials and design for stream bank erosion. Continue to 7. 7. Consider channel erosion control measures within the project limits as weU as downstream. Consider scour velocity. Continue to 8. 8. Include, where appropriate, energy dissipation devices at culverts. Continue to 9. 9. Ensure aU transitions between culvert ouflets/headwaUs/wingwaUs and channels are smooth to reduce turbulence and scour. Continue to 10. 10. Include, if appropriate, detention facUities to reduce peak discharges. Continue to 11. 11. "Hardening" natural downstream areas to prevent erosion is not an acceptable technique for protecting channel slopes, unless pre-development conditions are determined to be so erosive that hardening would be required even in the absence of the proposed development. Continue to 12. 12. Provide other design principles that are comparable and equaUy effective. Continue to 13. 13. End V Total Project Site Area 0.78 AC (Acres or ft^ 5 SWMP-October 2014 201 Walnut Townhomes Estimated amount of disturbed area: 0.78 AC (Acres or ft^ (If > 1 acre, you must also provide a WDID number from the SWRCB) Complete A through C and the calculations below to determine the amount of impervious surface on your project before and after constmction. A. Total size of project site: 0.78 AC (Acres or ft^ B. Total impervious area (including roof tops) before construction 0.09 AC (Acres or ft^ C. Total impervious area (including roof tops) after construction 0.47 AC (Acres or ft^) Calculate percent impervious before construction: B/A— 11 % Calculate percent impervious after construction: C/A = 60 % TEMPORARY CONSTRUCTION BMPS V SUt Fence • DesUting Basin V Fiber RoUs V Gravel Bag Berm V Street Sweeping and Vacuuming • Sandbag Barrier V Storm Drain Inlet Protection V Material Delivery and Storage V StockpUe Management V SpUl Prevention and Control V Solid Waste Management V Concrete Waste Management V Stabilized Construction Entrance/Exit • Water Conservation Practices • Dewatering Operations V Paving and Grinding Operations V Vehicle and Equipment Maintenance • Any minor slopes created incidental to construction and not subject to a major or minor grading permit shaU be protected by covering with plastic or tarp prior to a rain event, and shaU have vegetative cover reestablished within 180 days of completion of the slope and prior to final building approval. SWMP-October 2014 201 Walnut Townhomes SECTION II APPLICABLE STORM WATER STANDARDS TABLE 3: PRIORITY STATUS DETERMINATION Yes V No • A Housing subdivisions of 10 or more dwelling units. Examples: single-family homes, multi-family homes, condominiums, and apartments. Yes • No V B Commercial—greater than one acre. Any development other than heavy industry or residential. Examples: hospitals; laboratories and other medical facilities; educational institutions; recreational facilities; municipal facilities; commercial nurseries; multi- apartment buildings; car wash facilities; mini-malls and other business complexes; shopping malls; hotels; office buildings; public warehouses; automotive dealerships; airfields; and other Hght industrial facilities. Yes • No V C Heavy industry—^greater than one acre. Examples: manufacturing plants, food processing plants, metal working facilities, printing plants, and fleet storage areas (bus, truck, etc.). Yes • No V D Automotive repair shops. A facility categorized in any one of Standard Industrial Classification (SIC) codes 5013, 5014, 5541, 7532-7534, or 7536-7539. Yes • No V R Restaurants. Any facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (SIC code 5812), where the land area for development is greater than 5,000 square feet. Restaurants where land development is less than 5,000 square feet shall meet all SUSMP requirements except for structural treatment BMP and numeric sizing criteria requirements and hydromodification requirements. Yes • No V F Hillside development greater than 5,000 square feet. Any development that creates 5,000 square feet of impervious surface and is located in an area with known erosive son conditions, where the development wiU grade on any natural slope that is twenty- five percent or greater. Yes a No V G Environmentally Sensitive Areas (ESAs). AU development located within or directiy adjacent to or discharging directiy to an ESA (where discharges from the development or redevelopment wiU enter receiving waters within the ESA), which either creates 2,500 square feet of impervious surface on a proposed project site or increases the area of imperviousness of a proposed project site to 10% or more of its naturaUy occurring condition. "Directiy adjacent" means situated within 200 feet of the ESA. "Discharging directiy to" means outflow from a drainage conveyance system that is composed entitely of flows from the subject development or redevelopment site, and not commingled with flows from adjacent lands. Yes • No H Parking lots 5,000 square feet or more or with 15 or more parking spaces and potentiaUy exposed to urban mnoff. Yes • No V I Street, roads, highways, and freeways. Any paved surface that is 5,000 square feet or greater used for the transportation of automobiles, trucks, motorcycles, and other vehicles. Yes No .) RetaU GasoUne Outiets (RGOs) that are: (a) 5,000 square feet or more or (b) a projected Average DaUy Traffic (ADT) of 100 or more vehicles per day. SWMP-October 2014 201 Walnut Townhomes TABLE 4: EXCEPTIONAL THREAT TO WATER QUALITY DETERMINATION No. CRITERIA YES NO INFORMATION 1. Is aU or part of the proposed project site within 200 feet of waters named on the Clean Water Act (CWA) Section 303(d) Ust of Water QuaUty Limited Segments as impaired for sedimentation and/or turbidity? V If YES, continue to 2. IfNO,goto 5. 2. WUl the project disturb more than 5 acres, including aU phases of the development? If YES, continue to 3. If NO, go to 5. 3. WUl the project disturb slopes that are steeper than 4:1 (horizontal: vertical) with at least 10 feet of reUef, and that drain toward the 303(d) Usted receiving water for sedimentation and/or turbidity? If YES, continue to 4. IfNO,goto5. 4. WUl the project disturb soUs with a predominance of USDA-NRCS Erosion factors kf greater than or equal to 0.4? If YES, continue to 6. IfNO,goto5. 5. Project is not required to use Advanced Treatment BMPs. Document for Project FUes by referencing this checldist. 6. Project poses an "exceptional threat to water quaUty" and is required to use Advanced Treatment BMPs. V Advanced Treatment BMPs must be consistent with WPO section 67.81 l(b)(20)(D) performance criteria TABLE 5: HYDROMODIFICATION DETERMINATION QUESTIONS YES NO Information 1. WUl the project reduce the pre-project impervious area and are the unmitigated post-project outflows (outflows without detention routing) to each oudet location less as compared to the pre-project condition? V If NO, continue to 2. If YES, go to 7. 2. Would the project site discharge runoff directiy to an exempt receiving water, such as the Pacific Ocean, San Diego Bay, an exempt reservoir, or a tidaUy-influenced area? If NO, continue to 3. IfYES,goto7. 3. Would the project site discharge to a stabilized conveyance system, which has the capacity for the ultimate Qm, and extends to the Pacific Ocean, San Diego Bay, a tidaUy- V If NO, continue to 4. IfYES,goto 7. SWMP-October 2014 201 Walnut Townhomes influenced area, an exempt river reach or reservoir? 4. Does the contributing watershed area to which the project discharges have an impervious area percentage greater than 70 percent? V If NO, continue to 5. If YES, go to 7. 5. Is this an urban infiU project which discharges to an existing hardened or rehabUitated conveyance system that extends beyond the "domain of analysis," where the potential for cumulative impacts in the watershed are low, and the ultimate receiving channel has a "Low" susceptibiUty to erosion as defined in the SCCWRP channel assessment tool? V If NO, continue to 6. IfYES,goto7. 6. Project is required to manage hydromodification impacts. V Reference "HydromocUfication AppUcability Determination" of the City of Carlsbad SUSMP. 7. Project is not required to manage hydromodification impacts. SWMP-October 2014 SECTION 2: IDENTIFY POLLUTANTS, BMP SIZING AND Re-()e»gn En«(py 14. Hydmnodilicaiion CtmniU RsfvlKit bo to F rgure 2 2 cf Decisis Matrix FIGURE 2-1. HMP AppUcabUity Determination* *rcfer to expancied HMP exemption criteiia below for justifications required on each node 30 City of Carlsbad SUSMP - January 14, 2011 ^^^^ ARLSBA STORM WATER STANDARDS QUESTIONNAIRE E-34 Develofim e n .f S e rvic e s Land Oevelopment Engineering 1635 Faraday Avenue 760-60.1-27S0 www.carLsbadca.Hov INSTRUCTIONS: To address post-development pollutants that may be generated frcm 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 Engineenng Standards (Volume 4, Chapter 2) at v/vvtv cafi.sbadca.qov/sjsndaids. Initially this questionnaire must be compieied by the applicant in advance of submitting for a deveiopment application (subdivision, discreiionary permits and/or construction permits) The results of the questionnaire determine the level of storm water standards that must be applied to a proposed devetopment or redevelopment project Depending on the outcome, your project will either be subject to 'Standard Stormwater Pvequirements' or be subject to additiona! critena called -Priority Developmenl Project Requirements'. Many aspects of project site design are dependent upon the storm water standards applied to a project. Your responses to the quesMonnaire represent an initial assessment of the proposed project conditions and impacts. City staff has responsibiiity for making the final assessment after submission of the devetopment application. If staff determines that the questionnaire was incorrectly filled out and is subject to more stringent storm water standards than initially assessed by you, this will result in the return of the developmem application as incomplete. In this case, please make the changes to the questionnaire and resubmit to the City, If you are unsure about the meaning of a question or need heip in determining hov,? to respond to one or more of the queslions, please seek assistance from Land Development Engineering staff. A separate compleled and signed questionnaire must be submitted for each new development application submission Only one completed and signed questionnaire is required when multiple devetopment applications for the same project are submitted concurrently. In addition to this questionnaire, you must also complete, sign and submit a Project Threat Assessment form with construction permits for the projecl, ^piease starl by compleling SecliorTTVncTfoJto inslruclsons When completed, sign the form at the end and submi' this ¥/iih yoar apphcation to the ctty. SECTION 1 NEW DEVELOPMENT Docs your project meel one or more ofthe foilowing criteria: YES NO 1 Houslna subdMslom of 10 or mans t/woWnq anits Examples: smgle family homes, multi-family nomas _ condorrtifstum and apartments _„ 2 Commorclal- amatertlmn l-acre. Am development otner ',han heavy mdusiry or resrtential Examples hospitals, laboratories and other medical faalittes; educational institutions; recreaiional faciiiiies; municipal facilities, commercial nurseries, mulli-apartment busidinvgs, car wash facilities. mini-msHs and other business complexes; shopping malls, hotels; office buildmos, public warehouse's: automotive dealerships; sifficlds. and other iignt industrial facilities. Heavy tftdustriat / Industry- greater than 1 acre Examples manufaaoiing plants, food processing plants, metal working facilities, pnnting plants, and fleet storage areas jbus. ifuck _etcj ~Aatomotim repair shop A facility categorized in nny one of Standard Industrial Classification (SiC) codes 5013. 5014, 5541, 7532-7534, and 7535-7539 Rostmrants Any facility <hat sells prepared fsods and drinks for csnsumption including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (SIC code 5812). v/here the land area for development iS greater than 5,000 squ3te i£ei Rt-staurams v.nere land development !S less than 5 000 square feet shaH meet all SUSMP requirenierts except for structural treatment BMP and numeric sizing criteria requHW.entsjn£tv^f^ X X X X X E-34 Page 1 of 3 REV t/i4/|t CARLSBAD STORW WATER STANDARDS QUESTIONNAIRE %I0 "' w De irelop rti en t 5e r vices Land Development Engineering 1635 Faraday Avenue 760-602-2750 www .carlsbadca.gov 6. Hillside dBvelopment Any development that creates more than 5.000 square feet of impervious surface and ss located in an area with l<nown erosive soi! conditions, v/here the development will grade on any natural slops that is twenty-fi^e percent (25%) or greater. 7 Bmironmentallv Sensitive Area (BSA}' AH devaiopment located •.v.tisin or directly adjacent' to or discharging diredly'* to an ESA {where discharges from tt^e development or redevelopment will enter receiving v/aters withm the ESA), wtiich either creates 2.S00 square feet or more of impervious surface on a proposed project stte or increases trie area of imperviOusness of a prooosed projacs site 10y» or rnoie of its naturally occurring condition. „ a Patkim lot Area of 5.6'o5 square feef or more, or With IS or more paiking spaces, and potentially exposed to urban runatf .„...., ^ ^ 9, Stroets. mads, hiahwavs. and freeways. Any paved surface thai is 5,000 square feet or greater used for the iransportation of automobiles, trucJ^s. motorcydes. and other vehicles 10' fjetall GasoUne Outlets Serving more than 100 vehides per day and greater than 5.000 square feet t1 Coastal Develooment Zone Any project located with n 200 feat of tr.e f^aciftc Ocean and (i| creates more than 2500 square feet of impervious surface or (2) increases impervious surface on property by more than 10%. 12" Mam than l-acre of disturbance Project results in the disturbance of i-acre er more of land and is considered a Poliutant-generaang OeveSocmsnt Project*. X X X X "t 6ov.ionm«fitally Smsr.m A.'«a«. inciuds ijot ar« ml hT.tm aiJ C!e,ifs Ac! Sect-wi 303(d/ ^•r.r.;.,tf:C wa'c-; boa.es. areai; aes-g^ated a* Arejs c' SX'K.i'. Btoiomcsi S.gnificar.a! oy tht- St.ile Water R6»ufC0S CCMIUOI tJcaid (V/a!t>t QuaMy Ca^irsl Pian fof ins? San Difiga Basm (1SS4; and amersd^ien-s). watej buii.t:, aesignated with fhe RARE tserjaiiCiai use by ihe State mH't R'ssawras Controi f^oara (V/,Mer Ouaiity Cettlfol Plan (or the San Dicgo Basm (1994) .-ind aivierrfmi-nf.( 8'«as designalea es pf<?&wves c? tticif equfvawnt under lr;« r.1«;t Speosi Ct>fis<-r.'aL-e*i Pf3<5f.-..-»J 'Mtn-.n im- Ot.s-, ma Coani/ ef S<-«fl Diego, ans any tj!i;«r c«u:.;*k"5! for-nemaii/ sen$.".>ve s-ea;. -A-h-iti have bt&n ;<j<»r,!if.e!: r,/ {ha Cope'mtit'iu 3 'Dmcnmgmg ttirt-aly 10" means outflow from a anmaga conve j-;ince system H'.-st is composed tfnt.rely ot tiom from me sutsj«ct caveifipnse.it or fedftvworjmeM «te, and not cftwwftgled Witts fiow frorr! ad|flC45n! lands, 4 Pc.-'Laftt-senBf.l!.:ij D&v^lc^n-i:-.: P?c.acts ate Itsoss p-C;tv*ti try. -^-.ir.r,,} ;:o:iumPis at ;e.'!!;!s g-e.^!i-' Sft^-i oackgrcir.d levels In g«nefBi, tnss?? mclude a< ps«ieett K-ai 'ccnin'Lte te ats «<c«eaancK to fl,T mpsis^U water fctdy 0.' y-isa! ««a!i» c-^.- imperv o«)s sudsces fifc-aier mar; 5000 wuare feet a«a.-c? mtroa^cft lassdscafSirtg arc-js !h.i! require rsutme use o! feftAZ<!»s atsa pcsilwiSfis In mes! case* I'nedi palnway pfCjects that mv ias infrequent vutticse usa, sucn.« erner.jency or mamimsmx occess. or for pea«Sttian o.' bicyde use. are noi considered nrilSutaffl-gwiftaSing D««!df;mi'm Pfojett:, if ttioy sw tuiU wah pervious suifftces cr it tnr^y snest So* to su?r0u!5ai»^ pewiSBS s«rtas«i INSTRUCTIOt^S; Sectior) 1 Results; If you answered YES to ANY of the questtons above, ysijr project is subjed f© Prioiity Deveiopment Project requifements. Skip Section 2 and please proceed to Section 3, Check the 'meets PRIORITY DEVEt,OPMENT PROJECT requirements' box In Ss^aion 3. Additional storm water requirements wli apply per the SUSMP. jf you answered NO to ALL of the questions above, then please proceed to Section 2 and failow the instructions^ E-34 Page 2 of 3 REV 1/I4/11 ' ^ CITV or ARLSBAD STORM WATER STANDARDS QUESTIONNAIRE Development SerWces Land Devebpment Engineering 1635 Faraday Avenue 760-602-275Q www.carlsbadca.gov SECTION 2 SIGNIFICANT REDEVELOPMENT INSTRUCTIONS: Complete the questions below regardlna your project 1 PrOjec! resultiln the disturbancTHTlTcre or more of land and is considered 3 PolTutan!-generating Dovelcj^ment Preject *? YES I NO INSTRUCTIONS if you answered NO. please proceed to question 7. ii VSU answered YES then you ARE a significant redevetopment and you ARE subiect to PRIORITY OEVELOPMENT PROJECT requirements Please check the "meets PRIORITY DEVEIOPMENT PROJECT f£qutfemerits:jiO)nnS8^^ _ 2, Is the projecf redeveloping an existing priority Pm^^^j^^£!^21^!2S^^~^ defined m Section; 'INS TRUCTIONS, If yOu ansv/ertd YES. please proceed to question 3 !f you answered NO then you ARE NOT a significant redevelopment and your project is subjeci to STANDARD STORfvlWATER REQUIREMENTS. Rease checK the -does not meet PDP requirements' box Section 3 bejgw__ , .—_ 1 Is the work limited lo trencf)ing and resun'acing associated wilh utility wofi<; resurtacing snd reconfiguring suiface parking lots and existing roadways, new sidewalk. bAe lane on existing road and/or rsuiine maintenance of damaged pavement sucn as pothole repair^ Resurfadng'rcconfigur.ng parking lots is where the woft does not expose underlying soil during construction INStRUCTlONS If you answered NO. then procc-ed so quest;on 4 If you answered YES. then you ARE NOT a significant recevelopment and your project is subject to STANDARD STORMWATER REQUIREMENTS. Please check the 'does not meet PDP requirements" box in Section 3 below. 4 Wlli your'riaevetopment pf ojei create. reoSaca. or add ail^si S.OOO square feet cf impervious surfaces on existing developed property or will vour projecl be locaied wrthtn 200 feet of the Pacific Ocean and (1) create 2500 square feet er more of impervious surface or (2) increases impervious surface on the property by more tfian 10%? Replacement of existing impervious surfaces indudes any activity that is not patt of routine maintenance whaiQ impervious matenalCs) are removed, exposing underlying soil during cgnslmction ^ — •w«.«»iW fseCTS^ysaESy INSTRUCTIONS if youanswered YES you ARE a sigriificam redevelopment, and you ARE subjeci to PRIORITY DEVELOPMENT PROJECT requirements. Ptease check the "meets PRIORITY DEVELOPMENT PROJECT requirements" box in Secfion 3 below. Re SUSf.lP to find out if SUSMP requirements apply to your preject envelope or the entire project site If yeu answered NO. then you ARE NOT a significant redevelopment and your project is subject to STANDARD STORMWATER REQUIREMENTS. Please check fhe 'docs not meet PDP tequirements' box sn Section 3 below. View "for definition see Footnote 4 on page 2 SECTION 3 QUESTIONNAIRE RESULTS '4 • oroje'n meets PRIORITY DEVELOPfJIENT PROJECT (POP) requifements and must comply with additional stormwater cnteria j per the SUSMP and I uncerstand I must prepare a Stortr Wafer Management Plan for submittal as lime of zpoUcsmn. i urtderstand j flow control (hydromodtfication) requiremenis may apply to my project. Refer to SUSMP for details j My project doos not meet PDP requirements and must only comply with STANDARD STORMWATER REQUIREMENTS per the | SUSMP. As pan of these requirements. I will incorporate low impac. develootr.ent sirategigsjhrouahoi^ ' Applicant tnformation and Signatuie Box ftii's B-itt tu! Cle <J!.t> Ooy Address; ^SS ti ftvl^ lOl.^Tf % Assessor's Parcel Nurai3er{SK Applicant Name; Applicant Title; ^t^fe^HSfe^ Ai^cant Sigije^ure; Date: City Conoirrencc VES NO E-34 Paqe 3 of 3 REV 1/14/11 201 Walnut Townhomes SECTION III IDENTIFY POLLUTANTS OF CONCERN WATERSHED • San Juan 901 • Santa Margarita 902 • San Luis Rey 903 V Carlsbad 904 • San Dieguito 905 • Penasquitos 906 • San Diego 907 • Sweetwater 909 • Otay 910 • Tijuana 911 • Whitewater 719* • Clark 720* • West Salton 721* • Anza Borrego 722* • Imperial 723* http://www, waterboards.ca.gov/sandiego/water issues/programs/basin plan/index.shtml HYDROLOGIC SUB-AREA NAME AND BASIN NUMBER(S) Basin Number Sub-Area Name 904.31 Los Monos Sub-Area http://www.waterboards.ca.gov/sandiego/water issues/programs/basin plan/index.shtml SURFACE WATERS that each project c ischarge point proposes to discharge to. SURFACE WATERS (river, creek, stream, etc.) Hydrologic Unit Basin Number Impairment(s) listed [303(d) listed waters or waters with established TMDLs ]. List the impairments identified in Table 7. Distance to Project Aqua Hediona Creek 904.31 Manganese, Selenium, Sulfates, Total Dissolved Solids 0.85 Miles Aqua Hediona Lagoon 904.31 Indicator Bacteria, Sedimentation / Siltation 1.5 Miles http://www.waterboards.ca.gov/water issues/programs/tmdl/docs/303dlists2006/epa/r9 06 303d reqtmdl s.pdf GROUND WATERS Ground Waters Hydrologic Unit Basin Number MUN AGR IND PROC GWR FRESH POW RECl REC2 BIOL WARM COLD WILD RARE SPWN Aqua Hediona Creek 904.31 • • • • • • • • http://www.waterboards.ca.gov/sandiego/water issues/programs/basin plan/index.shtml + Excepted from Municipal • Existing Beneficial Use o Potential Beneficial Use 10 SWMP-October 2014 201 Walnut Townhomes PROJECT ANTICIPATED AND POTENTIAL POLLUTANTS Using Table 6, identify pollutants that are anticipated to be generated fi-om the proposed priority project categories. PoUutants associated with any hazardous material sites that have been remediated or are not threatened by the proposed project are not considered a pollutant of concem. TABLE 6: ANTICIPATED AND POTENTIAL POLLUTANTS GENERATED BY LAND USE TYPE General Pollutant Categories PDP Categories Sediments Nutrients Heavy Metals Organic Compounds Trash & I3ebria Oxygen Demanding Substances Oil& Grease Bacteria & Viruses l^esticides Detached Residential Development X X X X X X X Arrachfd Ur^idcntMl Di.-vclo|inii(.nt \ X X ])(!) 1> \ Commercial IDevelopment 1 acre or greater p(l) p(l) p X p(5) X p' Y>'- Heavy industry /industrial development X X X X X X Automotive Repair Shops X X X Restaurants X X X X ITillside Development >5,000 ft2 X X X X X X Parking l^ots p(l) p(l) X X p(l) X p(i) Retail Gasoline Oudets X X X X X Streets, J lighways & Freeways X p(l) X X p(5) X 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 poUutant if land use involves food or animal waste products. (4) Including petroleum hydrocarbons. (5) Including solvents. 11 SWMP-October 2014 201 Walnut Townhomes PROJECT POLLUTANTS OF CONCERN SUMMARY TABLE TABLE 7: PROJECT POLLUTANTS OF CONCERN Pollutant Category Anticipated (X) Potential (P) Surface Water Impairments Sediments X Sedimentation/Siltation Nutrients X Heavy Metals Organic Compounds Trash & Debris X Oxygen Demanding Substances P Oil & Grease P Bacteria & Viruses P Bacteria Pesticides X 12 SWMP-October 2014 201 Walnut Townhomes SECTION IV SOURCE CONTROL MEASURES TABLE 8: PROJECT SOURCE CONTROL BMPS Potential source of runoffpollutants Permanent source control BMPs Operational source control BMPs Landscape/ Outdoor Pesticide Use Preserve existing native trees, shrubs, and ground cover to the maximum extent possible. Design landscaping to minimize irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to stormwater pollution. Maintain landscaping using minimum or no pesticides Provide IPM information to new owners, lessees and operators. Refuse areas State how site refuse wiU be handled and provide supporting detail to what is shown on plans. If dumpsters or other receptacles are outdoors, show how the designated area will be covered, graded, and paved to prevent run-on and show locations of berms to prevent runoff from the Provide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky receptacles. Keep receptacles covered. Prohibit/prevent dumping of liquid or hazardous wastes. Post "no hazardous materials" signs. Inspect and pick up litter daily and clean up spills immediately. Keep spill control materials available on-site. See Fact Sheet SC-34, "Waste Handling and Disposal" in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Roofing, gutters, and trim. Avoid roofing, gutters, and trim made of copper or other unprotected metals that may leach into runoff Plazas, sidewalks, and parking lots Drain to landscape area/ bioretention basin Plazas, sidewalks, and parking lots shall be swept regularly to prevent the accumulation of litter and debris. Debris from pressure washing shall be collected to prevent entry into the storm drain system. Washwater containing any cleaning agent or degreaser shall be coUected and discharged to the sanitary sewer and not discharged to a 13 SWMP-October 2014 201 Walnut Townhomes storm drain. Fire Sprinkler Test Water Provide means to drain fire sprinkler test water to the sanitaty sewer. See the note in Fact Sheet SC- 41, "Building and Grounds Maintenance," in the CASQA Stomiwater Quality Handbooks at www.cabmphandbooks.com See Table 8 for proposed source control BMP's appUcable to this project. 14 SWMP-October 2014 201 Walnut Townhomes II' Tl lliSli SOURCES WILL BE ON TI II ' PROJECT SITE ... 1 Potential Sources of Runoff Pollutants - List in Table ! THEN YOUR STORMWAll^R CONTROL PLAN SHOULD INCLUDE THESE SOURCE CONTROL BMPs Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative V A. On-site storm drain inlets •v/ Locations of inlets. V B. Interior floor drains V C. Interior parking garages V Dl. Need for future indoor & structural pest control V Mark all inlets with the words "No Dumping! Flows to Bay" or similar where feasible. Maintain and periodically repaint or replace inlet markings. Provide stormwater pollution prevention information to new site owners, lessees, ot opetatots. See applicable operational BMPs in Fact Sheet SC-44, "Drainage System Maintenance," in the CASQA Stormwater Quality Handbooks at wwwxj!bmp_handb^^ Include the following in lease agreements: "Tenant shall not allow anyone to discharge anything to storm drains or to store ot deposit matetials so as to create a potential discharge to storm drains." State that interior floot will be plumbed to sanitaty sewet. Inspect and maintain dtains to ptevent blockages and ovetflow. State that patking garage floot drains will be plumbed to the sanitary sewer. Inspect and maintain drains to prevent blockages and ovetflow. Note building design features that discourage entry of pests. Provide Integrated Pest Management information to owners, lessees, and operators. 15 SWMP-October 2014 201 Walnut Townhomes IF THliSI' SOURCES WILL BE ON TI IF: PROJECT SITE ... 1 Potential Sources of Runoff Pollutants - List in Table i THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCE CONTROL BMPs Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative D2. Landscape/ Outdoor Pesticide Use Note: Should be consistent with project landscape plan (if applicable). • Show locations of native trees ot areas of shrubs and ground covet to be undisturbed and retained. • Show self-retaining landscape areas, if any. V Show stormwater tteatment facilities. a • State that final landscape plans will accomplish all of the following: Pteserve existing native ttees, shtubs, and gtound covet to the maximum extent possible. Design landscaping to minimize irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to stormwater pollution. Where landscaped ateas ate used to tetain or detain stormwater, specify plants that are tolerant of saturated soil conditions. Consider using pest-resistant plants, especially adjacent to hardscape. To insure successful establishment, select plants appropriate to site soils, slopes, climate, sun, wind, tain, land use, ait movement, ecological consistency, and plant intetactions. E. Pools, spas, ponds, decorative fountains, and other watet featutes. • Show location of watet feature and a sanitary sewer cleanout in an accessible area within 10 feet. If the local municipality requires pools to be plumbed to the sanitary sewet, place a note on the plans and state in the nattative that this connection will be made according to local requirements. Maintain landscaping using minimum or no pesticides. See applicable operational BMPs in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Stotmwatet Quality Handbooks at www.cabmphandbooks.com Ptovide IPM information to new owners, lessees and operators. See applicable operational BMPs in Fact Sheet SC-72, "Fountain and Pool Maintenance," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com 16 SWMP-October 2014 201 Walnut Townhomes IF' TFIESE SOURCES WILL BE ON Tin; PROji'CT SITF: ... THEN YOUR STORMWA'lTiR CCDNTROL PLAN SITOULD INCLUDE THESE SOURCE CON'FROL BMPs 1 Potential Sources of Runoff Pollutants - List in Table 1 Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative • I'. Food service • For restaurants, grocery stores, and other food service operations, show location (indoors or in a coveted atea outdoots) of a floot sink or othet atea fot cleaning floot mats, containets, and equipment. • On the dtawing, show a note that this drain will be connected to a gtease interceptor before discharging to the sanitaty sewet. V G. Refuse areas a Show where site refuse and recycled materials will be handled and stored for pickup. See local municipal requirements for sizes and other details of refuse areas. If dumpsters or other receptacles are outdoors, show how the designated area will be covered, graded, and paved to prevent run- on and show locations of berms to prevent runoff from the area. Any dtains ftom dumpstets, compactors, and tallow bin areas shall be connected to a grease removal device before discharge to sanitary sewer. • Describe the location and featutes of the designated cleaning area. • Describe the items to be cleaned in this facility and how it has been sized to insute that the latgest items can be accommodated. a ^j State how site tefuse will be handled and provide supporting detail to what is shown on plans. • State that signs will be posted on or near dumpsters with the words "Do not dump hazardous materials here" or similar. State how the following will be implemented: Provide adequate number of receptacles. Inspect receptacles regularly; repair or replace leaky receptacles. Keep receptacles coveted. Ptohibit/prevent dumping of liquid or hazardous wastes. Post "no hazardous materials" signs. Inspect and pick up litter daily and clean up spills immediately. Keep spill control materials available on- site. See Fact Sheet SC-34, "Waste Handling and Disposal" in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com 17 SWMP-October 2014 201 Walnut Townhomes IF THI'SF; SOURCES WILL BE ON TITl' PROJECT SITE ... TFIEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDI:' THESE SOURCE CONTROL BMPs Potential Sources of Runoff Pollutants - List in Table 1 Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative • I I. Industrial processes. • Show process area. If industrial processes are to be located on site, state: "All process activities to be performed indoors. No processes to drain to exterior or to storm drain system." • See Fact Sheet SC-10, "Non- Stormwater Discharges" in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com I. Outdoor storage of equipment or materials. (See rows J and K for source control measures for vehicle cleaning, repair, and maintenance.) • Show any outdoor storage areas, including how materials will be covered. Show how areas will be graded and bermed to prevent run- on or run-off from area. Storage of non-hazardous liquids shall be covered by a roof and/or drain to the sanitary sewer system, and be contained by berms, dikes, liners, or vaults. Storage of hazardous materials and wastes must be in compliance with the local hazardous materials ordinance and a Hazardous Materials Management Plan for the site. Include a detailed description of materials to be stored, storage areas, and structural features to prevent pollutants from entering storm drains. Where appropriate, reference documentation of compliance with the requirements of local Hazardous Materials Programs for: • Hazardous Waste Generation • Hazardous Materials Release Response and Inventory • California Accidental Release (CaLVRP) • Aboveground Storage Tank " Uniform Fire Code Article 80 Section 103(b) & (c) 1991 • Underground Storage Tank • See the Fact Sheets SC-31, "Outdoor Liquid Container Storage" and SC- 33, "Outdoor Stotage of Raw Materials " in the CASQA Stotmwatet Quality Handbooks at www.cabmphandbooks.com SWMP-October 2014 201 Walnut Townhomes IF THESE SCOURCES WILL BE ON TIIF: PROJI'CT SITE ... , TFIEN YOUR STORMWATER CONTROL PLAN SHOULi:) INCLUDE THESE SOURCE CONTROL BMPs 1 Potential Sources of Runoff Pollutants - List in Table I Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative • J Vehicle and Equipment Cleaning • Show on drawings as appropriate: (1) Commercial/industrial facilities having vehicle / equipment cleaning needs shall either ptovide a covered, bermed area for washing activities ot discourage vehicle/equipment washing by removing hose bibs and installing signs prohibiting such uses. (2) Multi-dwelling complexes shall have a paved, bermed, and covered car wash area (unless car washing is prohibited on-site and hoses are provided with an automatic shut- off to discourage such use). (3) Washing areas for cars, vehicles, and equipment shall be paved, designed to ptevent run-on to or runoff from the area, and plumbed to drain to the sanitary sewet. (4) Commercial car wash facilities shall be designed such that no runoff from the facility is discharged to the storm drain system. Wastewater from the facility shall discharge to the sanitary sewer, or a wastewater reclamation system shall be installed. If a car wash area is not provided, describe measures taken to discourage on-site car washing and explain how these will be enforced. Describe operational measures to implement the following (if applicable): • Washwater from vehicle and equipment washing operations shall not be discharged to the storm drain system. • Cat dealerships and similar may rinse cats with watet only. • See Fact Sheet SC-21, "Vehicle and Equipment Cleaning," in the CASQA Stotmwatet Quality Handbooks at www.cabmphandbooks.com 19 SWMP-October 2014 201 Walnut Townhomes II' THESF: SOURCES WILL BE ON TI II' PROJECT SITE ... ... THEN YOUR STORMWATI'R CONTROL PL.f\N SHOULD INCLUDI- TFIESf: SOURCF: CONTROL BMPs 1 Potential Sources of Runoff Pollutants - List in Table 1 Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in T'ablc 8 and Narrative Operational BMPs—Include in Table 8 and Narrative K Vehicle/Equipment Repair and Maintenance • Accommodate all vehicle equipment repair and maintenance indoors. Or designate an outdoor work area and design the area to prevent run-on and runoff of stormwater. • Show secondary containment for exterior work areas where motor oil, brake fluid, gasoline, diesel fuel, radiator fluid, acid-containing batteries or other hazardous materials or hazardous wastes are used ot stoted. Drains shall not be installed within the secondary containment ateas. • Add a note on the plans that states eithet (1) thete ate no floor dtains, ot (2) floor drains are connected to wastewater pretreatment systems prior to discharge to the sanitary sewer and an industrial waste discharge permit •will be obtained. • State that no vehicle repair or maintenance will be done outdoors, or else describe the required features of the outdoor work area. • State that there are no floot drains or if thete ate floot dtains, note the agency ftom which an industtial waste dischatge petmit will be obtained and that the design meets that agency's tequirements. • State that there are no tanks, containers ot sinks to be used fot patts cleaning ot tinsing ot, if there are, note the agency from which an industrial waste discharge permit will be obtained and that the design meets that agency's tequitements. In the SUSMP report, note that all of the foUo-wing restrictions apply to use the site: No person shall dispose of, not permit the disposal, directly or indirectly of vehicle fluids, hazardous materials, or rinsewater from parts cleaning into storm drains. No vehicle fluid removal shall be performed outside a building, nor on asphalt or ground surfaces, whether inside or outside a building, except in such a manner as to ensure that any spilled fluid will be in an area of secondary containment. Leaking vehicle fluids shall be contained or drained from the vehicle immediately. No person shall leave unattended drip patts ot othet open containets containing vehicle fluid, unless such containers are in use or in an atea of secondary containment. 20 SWMP-October 2014 201 Walnut Townhomes IF THESF: SOURCES WILL BE ON THF: PROJECT SITE ... 1 Potential Sources of Runoff Pollutants - List in Table I TFIEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE TIIESE SOURCE CON'FROL BMPs Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative • L. Fuel Dispensing Areas Fueling areas' shall have impermeable floors (i.e., portland cement concrete or equivalent smooth impervious surface) that are: a) graded at the minimum slope necessary to ptevent ponding; and b) sepatated ftom the test of the site by a gtade bteak that prevents tun-on of stormwater to the maximum extent practicable. Fueling areas shall be covered by a canopy that extends a minimum of ten feet in each direction from each pump. [Altemative: The fueling area must be covered and the cover's minimum dimensions must be equal to or greater than the area within the grade break or fuel dispensing area'.] The canopy [or cover] shall not drain onto the fueling area. • The property o-wner shall dry sweep the fueling area routinely. • See the Business Guide Sheet, "Automotive Service—Service Stations" in the CASQA Stormwater Quality Handbooks at •www.cabmphandbooks.com ' Tlie fueling area sliatl be defined as tlie area extending a minimum of 6.5 feet from tlie comer of eacti fuel dispenser or the tength at wliich the hose and nozzle assembly may be operated plus a minimum of one foot, whichever is greater. 21 SWMP-October 2014 201 Walnut Townhomes II' THESE SOURCES WILL BE (.:iN THE PROJECT SITE ... 1 Potential Sources of Runoff Pollutants - List in Table I , THEN YOUR STORMWATFiR CONTROL PLAN SHOULD INCLUDE THIvSE S(5URCE CONTROL BMPs Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—^IJst in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative • M. Loading Docks Show a preliminary design fot the loading dock atea, including toofing and drainage. Loading docks shall be covered and/or graded to minimize run-on to and runoff from the loading area. Roof downspouts shall be positioned to direct stormwater away from the loading area. Water from loading dock areas should be drained to the sanitary sewer where feasible. Direct connections to storm drains from depressed loading docks are prohibited. Loading dock areas draining directly to the sanitary sewer shall be equipped v^ith a spill control valve or equivalent device, which shall be kept closed during periods of operation. Provide a roof overhang over the loading area or install door skirts (cowling) at each bay that enclose the end of the trailer. V N. Fire Sprinkler Test Water Provide a means to drain fire sprinkler test water to the sanitary sewer. Move loaded and unloaded items indoors as soon as possible. See Fact Sheet SC-30, "Outdoor Loading and Unloading," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com See the note in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Stormwater Quality Handbooks at •www.cabmphandbooks.com 22 SWMP-October 2014 201 Walnut Townhomes IF' THl'SE SOURCES WILL BE ON TFIE PROJECT SITE ... 1 Potential Sources of Runoff Pollutants - List in Table I .. THEN YOUR STORMWATER CONTROL PLAN SHOULD INCLUDE THESE SOURCE CONTROL BMPs Permanent Controls—Show on Source Control Exhibit, Attachment B Permanent Controls—List in Table 8 and Narrative Operational BMPs—Include in Table 8 and Narrative O. Miscellaneous Drain or Wash Water • Boiler drain lines • Condensate drain lines • Rooftop equipment • Drainage sumps V Roofing, gutters, and trim. • Boiler drain lines shall be directly or indirectly connected to the sanitary sewer system and may not discharge to the storm drain system. • Condensate drain lines may discharge to landscaped areas if the flow is small enough that runoff will not occur. Condensate drain lines may not discharge to the storm drain system. Rooftop mounted equipment with Q potential to produce pollutants shall be roofed and/or have secondary containment. Any drainage sumps on-site shall Q feature a sediment sump to reduce the quantity of sediment in pumped water. Avoid roofing, gutters, and trim made of copper or other unprotected metals that may leach into runoff. P. Plazas, sidewalks, and paridng lots. V Install pervious pavers. Plazas, sidewalks, and paridng lots shall be swept regularly to prevent the accumulation of litter and debris. Debris from pressure washing shall be collected to prevent entry into the storm drain system. Washwater containing any cleaning agent or degreaser shall be collected and discharged to the sanitary sewer and not discharged to a storm drain. 23 SWMP-October 2014 201 Walnut Townhomes SECTION V LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES TABLE 9: LID AND SITE DESIGN 1. Conserve natural Areas, SoUs, and Vegetation V Preserve weU draining soUs (Type A or B) V Preserve Significant Trees V Preserve critical (or problematic) areas such as floodplains, steep slopes, wetiands, and areas with erosive or unstable soU conditions • Other. Description: 2. Minimize Disturbance to Natural Drainages V Set-back development envelope from drainages V Restrict heavy construction equipment access to planned green/open space areas • Other. Description: 3. Minitnize and Disconnect Impervious Surfaces (see 5) • Clustered Lot Design V Items checked in 5 • Other. Description: 4. Minimize SoU Compaction V Restrict heavy construction equipment access to planned green/open space areas V Re-tiU soUs compacted by construction vehicles/equipment V CoUect & re-use upper soU layers of development site containing organic materials • Other. Description: 5. Drain Runoff from Impervious Surfaces to Pervious Areas LID Street & Road Design • Curb-cuts to landscaping • Rural Swales • Concave Median • Cul-de-sac Landscapkig Design • Other. Description: 24 SWMP-October 2014 201 Walnut Townhomes LID Parking Lot Design • Permeable Pavements • Curb-cuts to landscaping • Other. Description: LID Drivewav. Sidewalk, Bike-path Design V Permeable Pavements V Pitch pavements toward landscapkig • Other. Description: LID BuUdine Design • Cisterns & Rain Barrels V Downspout to swale or landscaping • Vegetated Roofs • Other. Description: LID Landscaping Design V SoU Amendments V Reuse of Native SoUs V Smart Irrigation Systems • Street Trees • Other. Description: 6. Minimize erosion from slopes V Disturb existing slopes only when necessary V Minimize cut and fiU areas to reduce slope lengths V Incorporate retaining waUs to reduce steepness of slopes or to shorten slopes • Provide benches or terraces on high cut and fiU slopes to reduce concentration of flows V Rounding and shaping slopes to reduce concentrated flow V CoUect concentrated flows in stabUized drains and channels • Other. Description: 25 SWMP-October 2014 201 Walnut Townhomes SECTION VI INTEGRATED MANAGEMENT PRACTICES TABLE 10: GROUPING OF POTENTIAL POLLUTANTS OF CONCERN (POCS) BY FATE DURING STORMWATER TREATMENT Pollutant Check Coarse Sediment and Trash Pollutants that tend Pollutants that tend Project to associate with to be dissolved Specific fine particles during follcwing treatment POCs treatment Sediment X X X Nutrients X X Heavy Metals X Organic Compounds X Trash & Debris X Oxygen Demanding X Bacteria X X Oil & Grease X Pesticides X TABLE 11: GROUPS OF POLLUTANTS AND RELATIVE EFFECTIVENESS OF TREATMENT FACILITIES Pollutants of Concem HiiTruiiU'in FadUties (UD) Settling Basins (Dry Ponds) Wet Ponds and Constructed Wetlands Infiltration Devices (].ID) Media 1 ^'liters Higher- rate biofllters I ligher- ratc media filters Trash Racks & Hydro -dynamic Devices V cgetated Swales Coarse Sediment and Trash High High High High High High High High High Pollutants that tend to associate with fine particles during treatment ni^.h High High High High Medium Medium 1.-OW Medium Pollutants that tend to be dissolved following treatment .Medium Low Medium High ].0W Low l^ow Low 26 SWMP-October 2014 201 Walnut Townhomes TABLE 12: PROJECT LID AND TC-BMPS LID and TC-BMP Type Water Quality Tteatment Only Hydromodification Flow Control Bioretention Facilites (LID) V Bioretention area X X • Flow-through Planter • Cistem with Bioretention Settling Basins (Dty Ponds) • Extended/dry detention basin with grass/vegetated Uning • Extended/dry detention basin with impervious lining Infiltration Devices (LID) • Infiltration basin • Infiltration trench • Other Wet Ponds and Constmcted Wetlands • Wet pond/basin (permanent pool) • Constructed wetiand Vegetated Swales (LID^*^) • Vegetated Swale Media Filters • Austin Sand FUter • Delaware Sand FUter • Multi-Chambered Treatment Train (MCTT) Higher-rate Biofilters • Tree-pit-style unit • Otiier Higher-rate Media Filters • Vault-based fUtration unit with replaceable cartridges • Odier Hydrodynamic Separator Systems • Swirl Concentrator • Cyclone Separator Trash Racks • Catch Basin Insert • Catch Basin Insert w/ Hydrocarbon boom • Odier 27 SWMP-October 2014 201 Walnut Townhomes Bioretention areas were chosen for their removal efficiencies, constmction ease, low cost to maintain and construct and their abUity to function properly even with very minimal maintenance and care. The bioretention areas were chosen as a means of mitigating peak flows as weU serving as a settling basin and are also designed to meet hydromodification criteria. 28 SWMP-October2014 201 Walnut Townhomes SECTION VII- SIZING TREATMENT CONTROL BMP'S- BIORETENTION BASIN AS IMP REFER TO DMA, BMP, HMP, LID EXHIBIT ATTACHED 29 SWMP-October 2014 Project Summary Project Name 201 Walnut Project Applicant Walnut Beach Townhomes Jurisdiction City ol Carlsbad Parcel (APN) 204-131-01,02,&03 Hydrologic Unit Carlsbad Compliance Basin Summary Basin Name: A Receiving Water: 1 Rainfall Basin Oceanside Mean Annual Precipitation (Inches) 13.3 Project Basin Area (acres): 0.18 Watershed Area (acres): 0.00 SCCWRP Lateral Channel Susceptibiity (H, M, L): SCCWRP Vertlflca! Channel Susceptibiity (H, M, L): Overall Channel Susceptibility (H, M, L): HIGH Lower Flow Threshold (% of 2-Year Flow): 0.1 Drainage IVIanagement Area Summary ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soli Slope 20645 20647 20648 Drains to LID BMP 1 At 0.00 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20645 20647 20648 Drains to LID Drains to LID BMP 1 A2 0.00 Pervious (Pre) Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20645 20647 20648 Drains to LID Drains to LID BMP 1 A3 0.01 Pervious (Pre) Pervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20649 20650 20651 Drains to LID BMP 1 A4 0.02 0.00 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Landscaping Concrete or asphalt Type A (low runolf - sandy soi... Flat - slope (less ... 20649 20650 20651 Drains to LID Drains to LID BMP 1 BMP 1 A5 0.02 0.00 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Landscaping Concrete or asphalt Type A (low runolt - sandy soi... Flat - slope (less ... Flat - slope (less ... 20649 20650 20651 Drains to LID Drains to LID BMP 1 BMP 1 A6 0.02 0.00 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20652 Drains to LID BMP 1 A7 0.01 Pervious (Pre) Pervious concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20653 Drains to LID BMP 1 A8 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20654 20655 Drains to LID Drains to LID BMP 1 A9 0.00 Pervious (Pre) Pervious (Pre) Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20654 20655 Drains to LID Drains to LID BMP 1 AIO 0.00 Pervious (Pre) Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20656 Drains to LID BMP 1 All 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20657 20658 Drains to LID BMP 1 A12 0.00 Pen/ious (Pre) Pervious (Pre) Concrete or asphalt Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20657 20658 Drains to LID BMP 1 A13 0.02 Pen/ious (Pre) Pervious (Pre) Concrete or asphalt Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20659 20660 20661 Drains to LID BMP 1 A14 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... 20659 20660 20661 Drains to LID BMP 1 A15 0.00 Pervious (Pre) Roofs Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20659 20660 20661 Drains to LID BMP 1 A16 0.01 Impen/ious (Pre) Roofs Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20662 Drains to LID BMP 1 A17 0.00 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20663 20664 Drains to LID Drains to LID BMP 1 BMP 1 A18 0.00 0.00 Pervious (Pre) Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20663 20664 Drains to LID Drains to LID BMP 1 BMP 1 A19 0.00 Pervious (Pre) Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20665 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 A20 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20666 20667 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 A21 0.01 0.00 Impervious (Pre) Pervious (Pre) Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20666 20667 Drains to LID Drains to LID Drains to LID BMP 1 A22 0.01 0.00 Impervious (Pre) Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20668 20669 Drains to LID Drains to LID BMP 1 BMP 1 A23 0.00 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20668 20669 Drains to LID Drains to LID BMP 1 BMP 1 A24 0.00 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20670 Drains to LID BMP 1 A25 0.00 Pen/ious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20671 Drains to LID BMP 1 A26 0.01 Impervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Roofs Type A (low runoff - sandy soi... 20672 20673 Drains to LID BMP 1 A27 0.00 Impervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20672 20673 Drains to LID BMP 1 A28 0.00 Impervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20676 Drains to LID BMP 1 A29 A30 0.00 Pervious (Pre) Impervious (Pre) Landscaping Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20677 Drains to LID BMP 1 A29 A30 0.01 Pervious (Pre) Impervious (Pre) Landscaping Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20678 Drains to LID BMP 1 A31 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20679 20680 Drains to LID Drains to LID BMP 1 BMP 1 A32 A33 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20679 20680 Drains to LID Drains to LID BMP 1 BMP 1 A32 A33 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... LID Facility Summary BMP ID Type Description Plan Area (sqft) Volume 1(cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (Inch) BMP 1 Bioretention A18, A25, &A32 143 119 0.00 0.003 0.3 Project Summary Project Name 201 Walnut Project Applicant Walnut Beach Townhomes Jurisdiction City of Carlsbad Parcel (APN) 204-131-01,02,&03 Hydrologic Unit Carlsbad Compliance Basin Summary Basin Name: B Receiving Water: 2 Rainfall Basin Oceanside Mean Annual Precipitation (Inches) 13.3 Project Basin Area (acres): 0.31 Watershed Area (acres): 0.00 SCCWRP Lateral Channel Susceptibiity (H, M, L): SCCWRP Vertlflca! Channel Susceptibiity (H, M, L): Overall Channel Susceptibility (H, M, L): HIGH Lower Flow Threshold (% of 2-Year Flow): 0.1 Drainage Management Area Summary ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soli Slope 20824 20825 20826 Drains to LID Drains to LID Drains to LID BMP 1 B1 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20824 20825 20826 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 B2 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20824 20825 20826 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 B3 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20827 20828 20829 Drains to LID BMP 1 B4 0.00 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20827 20828 20829 Drains to LID BMP 1 B5 0.00 Pervious (Pre) Landscaping Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20827 20828 20829 Drains to LID BMP 1 B6 0.01 Pen/ious (Pre) Landscaping Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20831 Drains to LID BMP 1 B7 0.01 Pervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... 20832 Drains to LID BMP 1 B8 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20834 20835 Drains to LID Drains to LID BMP 1 B9 0.00 0.00 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20834 20835 Drains to LID Drains to LID BMP 1 B10 0.00 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20836 Drains to LID BMP 1 Bit 0.00 Pervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... 20837 Drains to LID BMP 1 B12 0.00 Pervious (Pre) Landscaping Flat - slope (less ... 20838 20839 Drains to LID BMP 1 B13 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20838 20839 Drains to LID BMP 1 B14 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20840 Drains to LID BMP 1 B15 0.00 Pen/ious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20841 Drains to LID BMP 1 B16 0.00 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20842 Drains to LID BMP 1 B17 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20843 Drains to LID BMP 1 BIB 0.01 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20844 20845 Drains to LID BMP 1 Big 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20844 20845 Drains to LID BMP 1 B20 0.02 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20846 Drains to LID BMP 1 B21 0.01 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20847 20848 Drains to LID Drains to LID BMP 1 BMP 1 B22 B23 0.00 0.00 Pen/ious (Pre) Pervious (Pre) Roofs Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20849 Drains to LID BMP 1 B24 0.00 Pen/ious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20850 20851 Drains to LID Drains to LID BMP 1 B25 0.00 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20850 20851 Drains to LID Drains to LID BMP 1 B26 0.00 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... 20852 Drains to LID BMP 1 827 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy Flat - slope (less ... soi... Flat - slope (less ... 20853 20854 Drains to LID BMP 1 B28 0.00 Pervious (Pre) Landscaping Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20853 20854 Drains to LID BMP 1 B29 0.00 Pen/ious (Pre) Landscaping Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20855 Drains to LID BMP 1 B30 0.00 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20856 20857 Drains to LID Drains to LID BMP 1 BMP 1 B31 0.00 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20856 20857 Drains to LID Drains to LID BMP 1 BMP 1 B32 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20858 20859 Drains to LID BMP 1 B33 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20858 20859 Drains to LID BMP 1 B34 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20860 Drains to LID BMP 1 B35 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20861 20862 Drains to LID Drains to LID BMP 1 BMP 1 B36 B37 0.00 0.00 Pervious (Pre) Pervious (Pre) Landscaping Solid unit pavers on granular Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20863 Drains to LID BMP 1 B38 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff • sandy soi... Flat - slope (less ... 20864 20865 Drains to LID BMP 1 B39 840 0.00 0.00 Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20864 20865 Drains to LID BMP 1 B39 840 0.00 0.00 Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20866 Drains to LID BMP 1 841 0.00 Pervious (Pre) Solid unit pavers on granular Type A (low runoff - sandy soi... Flat - slope (less ... 20867 20868 Drains to LID Drains to LID BMP 1 B42 0.00 0.00 Pen/ious (Pre) Pervious (Pre) Concrete or asphalt Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20867 20868 Drains to LID Drains to LID BMP 1 843 0.00 0.00 Pen/ious (Pre) Pervious (Pre) Concrete or asphalt Concrete or asphalt Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20869 20870 20871 Drains to LID BMP 1 844 0.01 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Landscaping Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20869 20870 20871 Drains to LID Drains to LID BMP 1 BMP 1 B45 0.00 0.01 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Landscaping Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20869 20870 20871 Drains to LID Drains to LID BMP 1 BMP 1 B46 0.00 0.01 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Landscaping Roofs Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20872 Drains to LID BMP 1 847 0.01 Pen/ious (Pre) Roofs Type A (low runoff - sandy Flat - slope (less ... soi... 20873 Drains to LID BMP 1 848 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20874 Drains to LID BMP 1 B49 0.01 Pen/ious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20875 Drains to LID BMP 1 850 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20876 Drains to LID BMP 1 851 0.01 Pen/ious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20877 Drains to LID BMP 1 852 0.00 Pervious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20878 Drains to LID BMP 1 853 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20879 Drains to LID BMP 1 854 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat • slope (less ... 20880 Drains to LID BMP 1 855 0.00 Pervious (Pre) Landscaping Type A (low runoff soi... sandy Flat - slope (less ... 20881 Drains to LID BMP 1 856 0.00 Pen/ious (Pre) Landscaping Type A (low runoff soi... sandy Flat - slope (less ... LID Facility Summary BMP ID Type Description Plan Area (sqft) Volume 1 (cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (Inch) BMP 1 Bioretention B28, B52, B56 550 458 0.00 0.001 0.1 Project Summary Project Name 201 Walnut Project Applicant Walnut Beach Townhomes Jurisdiction City of Carlsbad Parcel (APN) 204-131-01,02,&03 Hydrologic Unit Carlsbad Compliance Basin Summary Basin Name: C Receiving Water: 3 Rainfall Basin Oceanside Mean Annual Precipitation (Inches) 13.3 Project Basin Area (acres): 0.28 Watershed Area (acres): 0.00 SCCWRP Lateral Channel Susceptibiity (H, M, L): SCCWRP Vertlflcal Channel Susceptibiity (H, M, L): Overall Channel Susceptibility (H, M, L): HIGH Lower Flow Threshold (% of 2-Year Flow): 0.1 Drainage Management Area Summary ID Type BMP ID Description Area (ac) Pre-Project Cover Post Surface Type Drainage Soli Slope 20641 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 C39 0.00 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Roofs Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20643 20644 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 C40 0.01 0.00 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Roofs Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20643 20644 Drains to LID Drains to LID Drains to LID BMP 1 C41 0.01 0.00 Pen/ious (Pre) Pervious (Pre) Pen/ious (Pre) Concrete or asphalt Roofs Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20882 20883 20885 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 BMP 2 C42 0.00 Pervious (Pre) Landscaping Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20882 20883 20885 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 BMP 2 C43 0.00 Pervious (Pre) Landscaping Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20882 20883 20885 Drains to LID Drains to LID Drains to LID BMP 1 BMP 1 BMP 2 C34 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20887 Drains to LID BMP 2 C35 0.01 Pervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... 20388 Drains to LID BMP 2 C36 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20890 20891 Drains to LID BMP 2 BMP 2 C37 0.00 Pen/ious (Pre) Landscaping Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20890 20891 Drains to LID BMP 2 BMP 2 C38 0.00 Pen/ious (Pre) Landscaping Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20893 Drains to LID BMP 3 C30 0.01 Pen/ious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... 20894 20895 Drains to LID Drains to LID BMP 3 BMP 3 C31 C32 0.00 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20894 20895 Drains to LID Drains to LID BMP 3 BMP 3 C31 C32 0.00 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20896 Drains to LID BMP 3 C33 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20898 20899 Drains to LID BMP 4 BMP 4 C25 C26 0.01 Pervious (Pre) Roofs Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... 20898 20899 Drains to LID BMP 4 BMP 4 C25 C26 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runolf - sandy soi... Flat - slope (less ... 20900 Drains to LID BMP 4 C27 0.00 Pen/ious (Pre) Landscaping Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20901 Drains to LID Drains to LID BMP 4 C28 0.00 0.01 Pervious (Pre) Landscaping Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20903 Drains to LID Drains to LID BMPS C19 0.00 0.01 Pervious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20904 Drains to LID Drains to LID Drains to LID BMP 5 BMPS BMP 5 C20 0.01 Pervious (Pre) Pervious (Pre) Pervious (Pre) Roofs Concrete or asphalt Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20905 20906 Drains to LID Drains to LID Drains to LID BMP 5 BMPS BMP 5 C21 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Roofs Concrete or asphalt Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20905 20906 Drains to LID Drains to LID Drains to LID BMP 5 BMPS BMP 5 C22 0.00 Pervious (Pre) Pervious (Pre) Pervious (Pre) Roofs Concrete or asphalt Landscaping Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Type A (low runoff - sandy soi... Flat - slope (less ... Flat - slope (less ... Flat - slope (less ... 20907 20908 Drains to LID Drains to LID BMPS C23 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20907 20908 Drains to LID Drains to LID BMP 5 C24 0.00 Pervious (Pre) Landscaping Type A (low runoff - sandy soi... Flat - slope (less ... 20911 Drains to LID BMP 6 Ct 0.01 Pen/ious (Pre) Landscaping Type A (low runolt - sandy soi... Flat - slope (less ... 20913 Drains to LID BMP 6 C2 0.00 Pen/ious (Pre) Concrete or asphalt Type A (low runoff - sandy soi... Flat - slope (less ... 20913 Drains to LID BMP 6 Pen/ious (Pre) Type A (low runoff - sandy soi... Flat - slope (less ... 20914 Drains to LID BMP 6 C3 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20915 Drains to LID BMP 6 C4 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20916 Drains to LID BMP 6 CS 0.00 Pen/ious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20917 Drains to LID BMP 6 C6 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20918 Drains to LID BMP 6 C7 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20919 Drains to LID BMP 6 C8 0.00 Pervious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20920 Drains to LID BMP 6 C9 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20921 Drains to LID BMP 6 CIO 0.01 Pen/ious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less... 20922 Drains to LID BMP 6 C11 0.00 Pen/ious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20923 Drains to LID BMP 6 C12 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20924 Drains to LID BMP 6 C13 0.03 Pen/ious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20925 Drains to LID BMP 6 C14 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less ... 20926 Drains to LID BMP 6 CIS 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat slope (less ... 20927 Drains to LID BMP 6 C16 0.01 Pen/ious (Pre) Landscaping Type A (low runoff soi... sandy Flat slope (less ... 20928 Drains to LID BMP 6 C17 0.01 Pervious (Pre) Roofs Type A (low runoff soi... sandy Flat slope (less... 20929 Drains lo LID BMP 6 C18 0.00 Pervious (Pre) Concrete or asphalt Type A (low runoff soi... sandy Flat - slope (less ... LID Facility Summary BMP ID Type Description Plan Area (sqft) Volume 1 (cft) Volume 2(cft) Orifice Flow (cfs) Orifice Size (Inch) BMP 1 BMP 2 Bioretention Bioretention C42 67 56 0.00 0.000 0.000 0.0 0.0 BMP 1 BMP 2 Bioretention Bioretention C38 53 44 0.00 0.000 0.000 0.0 0.0 BMP 3 Bioretention C33 46 39 0.00 0.000 0.0 BMP 4 Bioretention C28 47 39 0.00 0.000 0.0 BMP 5 Bioretention C23 84 70 0.00 0.000 0.0 BMP 6 Bioretention C16 288 240 0.00 0.000 0.1 201 Walnut Townhomes SECTION VIII- SIZING JTYDROMODIFICATION- BIORETENTION BASIN AS IMP REFER TO DMA, BMP, HMP, LID EXHIBIT REFER TO SECTION IX Hydromodification sizing was determined by using the ^ sizing calculator. 30 SWMP-October 2014 201 Walnut Townhomes SECTION IX DOCUMENTATION OF STORM WATER DESIGN FOR IMP APPROACH DMA EXHIBIT 31 SWMP-October 2014 201 Walnut Townhomes SECTION X BMP FACILITY MAINTENANCE REQUIREMENTS ^ Responsible Party for Long-term Maintenance: Representative Name: Greg La Marca Company Name: 201 Walnut, LLC Phone Number: 760.802.4888 Street Address: 17828 VUlamoura Drive City/State/Zip: Poway, CA 92064 EmaU Address: greglamarca(^sbcglobal.net ^ Funding Source: 201 Walnut, LLC Bioretention Operation and Maintenance The operational and maintenance needs of a Bioretention Area are: The primary maintenance requirement for bioretention areas is that of inspection and repair or replacement of the treatment area's components. GeneraUy, this involves nothing more than the routine periodic maintenance that is required of any landscaped area. Plants that are appropriate for the site, chmatic, and watering conditions should be selected for use in the bioretention ceU. Appropriately selected plants wUl aide in reducing fertilizer, pesticide, water, and overaU maintenance requirements. Bioretention system components should blend over time through plant and root growth, organic decomposition, and the development of a natural soU horizon. These biologic and physical processes over time wiU lengthen the faculty's Ufe span and reduce the need for extensive maintenance. Routine maintenance shoiUd include a biannual health evaluation of the trees and shrubs and subsequent removal of any dead or diseased vegetation (EPA, 1999). Diseased vegetation shovUd be treated as needed using preventative and low-toxic measures to the extent possible. BMPs have the potential to create very attractive habitats for mosquitoes and other vectors because of highly organic, often heavUy vegetated areas mixed with shaUow water. Routine inspections for areas of standing water within the BMP and corrective measures to restore proper infiltration rates are necessary to prevent creating mosquito and other vector habitat. In addition, bioretention BMPs are susceptible to invasion by aggressive plant species such as cattaUs, which increase the chances of water standing and subsequent vector production if not routinely maintained. In order to maintain the treatment area's appearance it may be necessary to prune and weed. 32 SWMP-October 2014 201 Walnut Townhomes Furthermore, mulch replacement is suggested when erosion is evident or when the site begins to look unattractive. SpecificaUy, the entire area may require mtUch replacement every two to three years, although spot mulching may be sufficient when there are random void areas. Mulch replacement should be done prior to the start of the wet season. New Jersey's Department of Environmental Protection states in their bioretention systems standards that accumidated seditnent and debris removal (especiaUy at the inflow point) wUl normaUy be the primary maintenance function. Other potential tasks include replacement of dead vegetation, soU pH regulation, erosion repair at inflow points, mulch replenishment, uncloggUig the underdrain, and repairing overflow structures. There is also the possibUity that the cation exchange capacity of the soUs in the ceU wUl be significantiy reduced over time. Depending on poUutant loads, soUs may need to be replaced within 5-10 years of construction. Functional Maintenance Functional maintenance has two components: Preventive maintenance Corrective maintenance Preventive Maintenance Preventive maintenance activities to be instituted at a Bioretention Area are: • Trash and Debris. During each inspection and maintenance visit to the site, debris and trash removal wiU be conducted to reduce the potential for inlet and oudet stmctures and other components from becoming clogged and inoperable during storm events. • Sediment Removal. Sediment accumiUation, as part of the operation and maintenance program at a Swale, wUl be monitored once a month during the dry season, after every large storm (0.50 inch), and monthly during the wet season. SpecificaUy, if sediment reaches a level at or near plant height, or coiUd interfere with flow or operation, the sediment wiU be removed. If accumulation of debris or sediment is determined to be the cause of decUne in design performance, prompt action (ie., within ten working days) wiU be taken to restore the Swale to design performance standards. Removal of Standing Water. Standing water must be removed if it contributes to the development of aquatic plant communities or mosquito breeding areas. • Fertilization and Irrigation. The vegetation seed mix has been designed so that fertUization and irrigation is not necessaiy. FertUizers and irrigation wiU not be used to maintain the vegetation. • Elimination of Mosqmto Breeding Habitats. The most effective mosquito control program is one that eliminates potential breeding habitats. 33 SWMP-October 2014 201 Walnut Townhomes Corrective Maintenance Corrective maintenance is required on an emergency or non-routine basis to correct problems and to restore the intended operation and safe function of a Bioretention Area. Corrective maintenance activities include: • Removal of Debris and Sediment. Sediment, debris, and trash, which Unpede the hydrauUc fimctioning of a Swale and prevent vegetative growth, wUl be removed and properly disposed. Stmctural Repairs. Once deemed necessary, repairs to stmctural components of a Swale and its inlet and outiet stmcmres wiU be done within 10 working days. Embankment and Slope Repairs. Once deemed necessary, damage to the embankments and slopes of Swales wUl be repaired within 10 working days). Erosion Repair. Where a reseeding program has been ineffective, or where other factors have created erosive conditions (i.e., pedestrian traffic, concentrated flow, etc.), corrective steps wUl be taken to prevent loss of soU and any subsequent danger to the performance of a Swale. There are a number of corrective actions than can be taken. These include erosion control blankets, riprap. Maintenance Category Bioretention Areas: The maintenance of the bioretention areas, used as IMP and HMP mitigation, wUl be the responsibUity of the individual private land owner. The City shoiUd have only minimal concems for ongoing maintenance. The proposed bioretention areas inherentiy "take care of themselves", or property owners can naturaUy be expected to do so as an incident of taking care of their property. Annual Cost of Maintenance ANNUAL COST ESTIMATE: Bioretention Areas $47.895.00 TOTAL: $47,895.00 TWO-YEAR COST ESTIMATE: Bioretention Areas $95.790.00 TOTAL: $95,790.00 34 SWMP-October 2014 201 Walnut Townhomes TEN-YEAR COST ESTIMATE: Bioretention Areas $478.950.00 TOTAL: $478,950.00 35 SWMP-October 2014 201 Walnut Townhomes Date: City of Carlsbad Land Development Engineering 1635 Faraday Ave. Carisbad, CA 92008 Re: Final Certification of Treatment Control BMPs for 201 Walnut Townhomes To Whom It May Concern: AU Stormwater Treatment Control facUities have been constmcted in conformance with the approved Stormwater Management Plan, dated , in compUance with City of Carlsbad Standards and currendy accepted Engineering practices. Brian Ardolino, RCE 71651 " , Date 36 SWMP-October 2014