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HomeMy WebLinkAboutCT 14-05; MAGNOLIA TOWNHOMES; SWQMP; DWG 490-4A, PUD 14-08, CDP 14-27; 2016-11-21STORM WATER QUALITY MANAGEMENT PLAN SWQMP 16-03 For MAGNOLIA WALK PROJECT NO. CT 14-05 PUD 14-08 CDP 14-27 Prepared By: OMS CONSULTANTS, INC. SURENDER DEWAN, P.E. 12371 LEWIS STREET, SUITE 203 GARDEN GROVE, CA 92840 714.740.8840 Surender@DMSConsultantslnc.com Prepared For: TMS HIGHLAND INVESTMENTS, LLC 29250 PASEO SEDANO SAN JUAN CAPISTRANO, CA 92675 November 21, 2016 ISA BULLCITY OF CARLSBAD PRIORITY DEVELOPMENT PROJECT (PDP) STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) FOR MAGNOLIA WALK PROJECT NO. CT 14-05/ PUD 14-08/ CDP 14-27 SWQMP #: 16-03 ENGINEER OF WORK: SURENDER DEWAN, P.E. RCE 34559 PREPARED FOR: TMS HIGHLAND INVESTMENTS, LLC 29250 PASEO SEDANO SAN JUAN CAPISTRANO, CA 92675 (951) 801-0888 PDP SWQMP PREPARED BY: OMS CONSULTANTS, INC. 12371 LEWIS STREET, SUITE 203 GARDEN GROVE, CA 92840 (714) 740-8840 DATE OF SWQMP: November 21, 2016 R~Jlt\¥i!D .JJEC &8 2~ LAND DEVELOPMENT ENGINEERING TABLE OF CONTENTS PDP SWQMP Preparer's Certification Page Project Vicinity Map FORM 1-1 Applicability of Permanent, Post-Construction Storm Water BMP Requirements FORM 1-2 Project Type Determination Checklist (Standard Project or PDP) FORM l-3B Site Information Checklist for PDPs FORM 1-4 Source Control BMP Checklist for All Development Projects FORM 1-5 Site Design BMP Checklist for All Development Projects FORM 1-6 Summary of PDP Structural BMPs Attachment 1: Back.up for PDP Pollutant Control BMPs Attachment la: DMA Exhibit Attachment lb: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment le: Harvest and Use Feasibility S1=reening (when jpplicable) Attachment ld: Categorization of Infiltration Feasibility Condition (when applicable) Attachment le: Pollutant Control BMP Design Worksheets I Calculations Attachment 2: Backup for PDP Hydromodification Control Measures Attachment 2a: Hydromodification Management Exhibit Attachment 2b: Management of Critical Coarse Sediment Yield Areas Attachment 2c: Geomorphic Assessment of Receiving Channels Attachment 2d: Flow Control Facility Design Attachment 3: Structural BMP Maintenance Plan Attachment 3a: B Structural BMP Maintenance Thresholds and Actions Attachment 3b: Draft Maintenance Agreement Attachment 4: Single Sheet BMP (SSBMP) Plan 2 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 PDP SWQMP PREPARER'S CERTIFICATION PAGE Project Name: Magnolia Walk Project ID: CT 14-05/ PUD 14-08/ CDP 14-27 PREPARER'S CERTIFICATION I hereby declare that I am the Engineer in Responsible Charge of design of storm water best management practices (BMPs) for this project, and that I have exercised responsible charge over the design of the project as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with the requirements of the BMP Design Manual, which is based on the requirements of SDRWQCB Order No. R9-2013-0001 (MS4 Permit). I have read and understand that the City Engineer has adopted minimum requirements for managing urban runoff, including storm water, from land development activities, as described in the BMP Design Manual. I certify that this PDP SWQMP has been completed to the best of my ability and accurately reflects the project being proposed and the applicable BMPs proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I understand and acknowledge that the plan check review of this PDP SWQMP by the City Engineer is confined to a review and does not relieve me, as the Engineer in Responsible Charge of design of storm water BMPs for this project, of my responsibilities for project design. ~ ____ .... _ .... __ ............. Engineer of Work's Signature, PE Number & Expiration Date ( \.A,e u c:\ e. ~ tNl,l, Print Name Company Date 3 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 PROJECT VICINITY MAP Project Name: Magnolia Walk Project ID: CT 14-05/ PUD 14-08/ CDP 14-27 4 ~ ~ ~ ~ ~ MAGNOLIA Al/f. SllE LOCATIO~ ~ VICINIJsY MAP NORTH PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 t, r N CC ~ ~ ' ---, ' ,-, 1- ~ ~ ~ "il •=1£ Wj Storm Water Stanoar!os ~uestiomnaire Rart 1 For:m 1-1 ,, ' Carlsbatl BMP Design /\ i r~ "' lStor:m Water Intake form for: atl Developmeat PermitAJU~lications} Manual t ' I >m :I -'~~'---"-----~~~ '~------~-~ L~~---' ' ',,,J 5 Project Identification Project Name: Magnolia Walk Project ID: CT 14-05/ PUD 14-08/ CDP 14-27 I Date: 9/15/16 Determination of Requirements The purpose of this form is to itlentify permanent, post-construction requirements that apply to the project. This form serves as a short summary of applicable requirements, in some cases referencing separate forms that will serve as the backup for the determination of requirements. Answer each step below, starting with Step 1 and progressing through each step until reaching "Stop". Refer to BMP Design Manual sections and/or separate forms referenced in each step below. Step Answer Progression Step 1: Is the project a "development [gl Yes Go to Step 2. project"? See Section 1.3 of the BMP Design D No Stop. Manual for guidance. Permanent BMP requirements do not apply. No SWQMP will be required. Provide discussion below. Discussion/ justification if the project is not a "development project" (e.g., the project includes only interior remodels within an existing building): Step 2: Is the project a Standard Project, D Standard Stop. Priority Development Project (PDP), or Project Standard Project requirements exception to PDP definitions? apply, including Standard Project To answer this item, see Section 1.4 of the SWQMP. BM P Design Manual in its entirety for rgJ PDP PDP requirements apply, including PDP guidance, AND complete Form 1-2, Project SWQMP. Type Determination. Go to Step 3. D Exception Stop. to PDP Standard Project requirements apply .. definitions Provide discussion and list any additional requirements below. Prepare Standard Project SWQMP. Discussion/ justification, and additional requirements for exceptions to PDP definitions, if applicable: PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 c:i T "' %' -"' u -~~,,,,,. --"-"" ~ -"~ ~ "'~" '~ """'" ""'~lf:7@1:R'lil :,:· form bl Rage,! , · ' , i,::, i±S8.' '=--·-----"-------~~~----~ ~"~ ___ _,_ ~ "'--~--~ ~~ ~ __ ,,, __ ----= -~ ""' ff.~ • "'-~ fl ::iLl,"S:1il 6 Step Step 3. Is the project subject to earlier PDP requirements due to a prior lawful approval? See Section 1.10 of the BMP Design Manual for guidance. Answer D Yes [gl No Progression Consult the City Engineer to determine requirements. Provide discussion and identify requirements below. Go to Step 4. BMP Design Manual PDP requirements apply. Go to Step 4. Discussion I justification of prior lawful approval, and identify requirements (not required if prior lawful approval does not apply): Step 4. Do hydromodification control requirements apply? See Section 1.6 of the BMP Design Manual for guidance. D Yes [gl No PDP structural BMPs required for pollutant control (Chapter 5) and hydromodification control (Chapter 6). Go to Step 5. Stop. PDP structural BMPs required for pollutant control (Chapter 5) only. Provide brief discussion of exemption to hydromodification control below. Discussion I justification if hydromodification control requirements do not apply: Per report prepared by Chang Consultants dated 5/3/16 (enclosed), the 10-year hydromodification flows from the project site will be contained in either non-erodible conveyance channels or storm drains to an enclosed embayment. Therefore, the project will not cause hydromodification impacts and qualifies for a hydromodification exemption. Step 5. Does protection of critical coarse sediment yield areas apply? See Section 6.2 of the BMP Design Manual for guidance. D Yes [gl No Management measures required for protection of critical coarse sediment yield areas (Chapter 6.2). Stop. Management measures not required for protection of critical coarse sediment yield areas. Provide brief discussion below. Stop. Discussion/ justification if protection of critical coarse sediment yield areas does not apply: The runoff surface drains along Magnolia Avenue and ultimately drains to an underground storm drain in Chestnut Street cu-de-sac. See letter from Chang Consultants include this report. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 , ,, -' , ' ''"iarm '1-2 n:,·~ Storm Water Standards ~uestior:maire ~art 2 , €aFlsbaa BMP Design Manual ~ t~ ---~-~~--~~----,, '' ' -~-j ~ ---~~ ~ -~ ~ ----~<lt~l Project Information Project Name: Magnolia Walk Project ID: CT 14-05/ PUD 14-08/ CDP 14-27 Project Type Determination: Standard Project or Priority Development Project (PDP) The project is (select one): [8:1 New Development D Redevelopment The total proposed newly created or replaced impervious area is: 22,942 ft2 (0.53) acres Is the project in any of the following categories, (a) through (f)? Yes No (a) New development projects that create 10,000 square feet or more of impervious [8:1 D surfaces (collectively over the entire project site). This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. Yes No (b) Redevelopment projects that create and/or replace 5,000 square feet or more of D [8:1 impervious surface (collectively over the entire project site on an existing site of 10,000 square feet or more of impervious surfaces). This includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. Yes No (c) New and redevelopment projects that create and/or replace 5,000 square feet or [8:1 D more of impervious surface (collectively over the entire project site), and support one or more of the following uses: (i) Restaurants. This category is defined as a facility that sells prepared foods and drinks for consumption, including stationary lunch counters and refreshment stands selling prepared foods and drinks for immediate consumption (Standard Industrial Classification (SIC) code 5812). (ii) Hillside development projects. This category includes development on any natural slope that is twenty-five percent or greater. (iii) Parking lots. This category is defined as a land area or facility for the temporary parking or storage of motor vehicles used personally, for business, or for commerce. (iv) Streets, roads, highways, freeways, and driveways. This category is defined as any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. 7 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 8 Yes No (d) New or redevelopment projects that create and/or replace 2,500 square feet or 12J D more of impervious surface (collectively over the entire project site), and discharging directly to an Environmentally Sensitive Area (ESA). "Discharging directly to11 includes flow that is conveyed overland a distance of 200 feet or less from the project to the ESA, or conveyed in a pipe or open channel any distance as an isolated flow from the project to the ESA (i.e. not commingled with flows from adjacent lands). Note: ESAs are areas that 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 Board and San Diego Water Board; State Water Quality Protected Areas; water bodies designated with the RARE beneficial use by the State Water Board and San Diego Water Board; and any other equivalent environmentally sensitive areas which have been identified by the Copermittees. See BMP Design Manual Section 1.4.2 for additional guidance. Yes No (e) New development projects that support one or more of the following uses: 12J D (i) Automotive repair shops. This category is defined as a facility that is categorized in any one of the following SIC codes: 5013, 5014, 5541, 7532- 7534, or 7536-7539. (ii) Retail gasoline outlets (RGOs). This category includes RGOs that meet the following criteria: (a) 5,000 square feet or more or (b) a projected Average Daily Traffic (ADT) of 100 or more vehicles per day. Yes No (f) New or redevelopment projects that result in the disturbance of one or more 12:1 D acres of land and are expected to generate pollutants post construction. Note: See BMP Design Manual Section 1.4.2 for additional guidance. Does the project meet the definition of one or more of the Priority Development Project categories (a) through (f) listed above? D No -the project is not a Priority Development Project (Standard Project). 12:1 Yes -the project is a Priority Development Project (PDP). The following is for redevelopment PDPs only: The area of existing (pre-project) impervious area at the project site is: ft2 (A) The total proposed newly created or replaced impervious area is: ft2 (B) Percent impervious surface created or replaced (A/B)*100: % The percent impervious surface created or replaced is (select one based on the above calculations): D less than or equal to fifty percent (50%) -only new impervious areas are considered PDP OR 12:1 greater than fifty percent (50%) -the entire project site is a PDP PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 HJ 4'1 = ~"' --OS > ~ c , ~ ,, s r ~ ~ '-'i J -,.; -, "":( ~, ff " jJ",{i Site lniorrnmatimn ~hiecl<list , Eorm I-BB (P~Pst 1 ," I Model BMP Design Manual l 'J lto11 ID!s I ' J -fol;~'~--~-~~---~~ --~~-~ -_ -~---V -' ---- S ~~k~' ( --~ -< ,t %_s 9 Project Summary Information Project Name Project Address Assessor's Parcel Number(s) (APN (s)) Project ID Project Watershed (Hydrologic Unit) Parcel Area (total area of Assessor's Parcel(s) associated with the project) Area to be Disturbed by the project (Project Area) Project Proposed Impervious Area (subset of Project Area) Project Proposed Pervious Area (subset of Project Area) Magnolia Walk 749 Magnolia Avenue 204-285-05 I 26-oo CT 14-05/ PUD 14-08/ CDP 14-27 Select One: D Santa Margarita 902 D San Luis Rey 903 ~ Carlsbad 904 D San Dieguito 905 D Penasquitos 906 D San Diego 907 D Pueblo San Diego 908 D Sweetwater 909 D Otay910 D Tijuana 911 0.68 Acres 0.68 Acres 0.54 Acres 0.14 Acres {29,620 Square Feet) (29,620 Square Feet) {23,690 Square Feet) (6,100 Square Feet) Note: Proposed Impervious Area + Proposed Pervious Area = Area to be Disturbed by the Project. This may be less than the Parcel Area. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Description of Existing Site Condition and Drainage Pattern Current Status of the Site (select all that apply): ~ Existing development D Previously graded but not built out D Agricultural or other non-impervious use D Vacant, undeveloped/natural Description I Additional Information: Existing Land Cover Includes (select all that apply): ~ Vegetative Cover ~ Non-Vegetated Pervious Areas ~ Impervious Areas Description I Additional Information: Underlying Soil belongs to Hydrologic Soil Group (select all that apply): D NRCS Type A ~ NRCS Type B D NRCS Type C D NRCS Type D Approximate Depth to Groundwater (GW): D GW Depth < 5 feet D 5 feet < GW Depth < 10 feet ~ 10 feet < GW Depth < 20 feet D GW Depth > 20 feet Existing Natural Hydrologic Features (select all that apply): D Watercourses D Seeps D Springs D Wetlands ~ None Description I Additional Information: 10 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Description of Existing Site Topography and Drainage: (How is storm water runoff conveyed from the site? At a minimum, this description should answer (1) whether existing drainage conveyance is natural or urban; (2) describe existing constructed storm water conveyance systems, if applicable; and (3) is runoff from offsite conveyed through the site? If so, describe). 11 The existing site is fairly flat and drains from north to south Existing drainage conveyance is natural, the runoff drains naturally to existing single family lots located along the southerly property line and then on to Anchor Way. There is no offsite runoff through the site. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Description of Proposed Site Development Project Description I Proposed Land Use and/or Activities: Proposed Magnolia Walk project is a 16 unit condominium development. List/describe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): Impervious features of the project include buildings, driveways, parking spaces, walkways and trash bin. List/describe proposed pervious features of the project (e.g., landscape areas): Pervious features of the project include landscape areas and pervious pavers. Does the project include grading and changes to site topography? ~Yes D No Description I Additional Information: Grading for the project includes grading for building pads to provide protection for 100 year flood, drainage to conform to City standards. Does the project include changes to site drainage (e.g., installation of new storm water conveyance system)? ~Yes D No Description I Additional Information: 12 The proposed drainage system consists of permeable pavers manufactured by UNI Eco-Stone. These pavers are installed in the center of the driveway. The pavers are laid over a bedding course of 1:Vi" to 2" thick aggregate which is laid over a stone open graded base. The overflow/secondary outlet from the site which consists of a PVC pipe which pumps the runoff from a pump station located at the south end of the property. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply): ~ On-site storm drain inlets D Interior floor drains and elevator shaft sump pumps ~ Interior parking garages D Need for future indoor and structural pest control ~ Landscape/outdoor pesticide use D Pools, spas, ponds, decorative fountains, and other water features D Food service D Refuse areas D Industrial processes D Outdoor storage of equipment or materials D Vehicle and equipment cleaning D Vehicle/equipment repair and maintenance D Fuel dispensing areas D Loading docks D Fire sprinkler test water D Miscellaneous drain or wash water D Plazas, sidewalks, and parking lots Description I Additional Information: 13 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 [\'', ,-~~-_-______ --~---___ --_ --~--,-~~qm1~ie'"'~~ke6 iiij~--~""' -· · -~---" , -~=-1' -,, ,,:;:: r=,p:"1'f:]Fj1 -~ h _ 1 ~J}lA Identification of Receiving Water and Pollutants of Concern Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): The site will drain via a force main to Magnolia Avenue which ultimately drains to Agua Herdionda Lagoon. List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs and/or Highest Priority Pollutants from the WQIP for the impaired water bodies: TMDLs / WQIP Highest Priority 303(d) Impaired Water Body Pollutant(s)/Stressor(s) Pollutant Agua Hedionda Lagoon Bacteria Sedimentation/siltation Identification of Project Site Pollutants* *Identification of project site pollutants is only required if flow-thru treatment BMPs are implemented onsite in lieu of retention or biofiltration BMPs (note the project must also participate in an alternative compliance program unless prior lawful approval to meet earlier PDP requirements is demonstrated) Identify pollutants expected from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6): Not Applicable to the Pollutant Project Site Sediment Nutrients Heavy Metals Organic Compounds Trash & Debris Oxygen Demanding X Substances Oil & Grease X Bacteria & Viruses X Pesticides 14 Expected from the Also a Receiving Water Project Site Pollutant of Concern X X X X X X X X PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Hydromodification Management Requirements Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? D Yes, hydromodification management flow control structural BMPs required. D No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. ~ No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete-lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. D No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides. Description I Additional Information (to be provided if a 'No' answer has been selected above): The runoff from the site eventually drains in storm drain towards the railroad tracks just southwest of Chestnut Avenue. The storm drain then parallels the east side of the railroad and continues southeasterly to a discharge point at the Agua Hedionda Lagoon. Per a report prepared by Chang Consultants, and included herein, the hydromodification flow will be contained in the storm drain system and have adequate energy dissipation at the outlet into the lagoon. Critical Coarse Sediment Yield Areas* *This Section only required if hydromodification management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? D Yes D No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? D 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite D No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps If optional analyses were performed, what is the final result? D No critical coarse sediment yield areas to be protected based on verification of GLUs onsite D Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 2.b of the SWQMP. D critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit. Discussion I Additional Information: Not applicable to the project. 15 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Flow Control for Post-Project Runoff* *This Section only required if hydromodification management requirements apply List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit. Not applicable to the project. Has a geomorphic assessment been performed for the receiving channel(s)? D No, the low flow threshold is 0.1Q2 (default low flow threshold) D Yes, the result is the low flow threshold is 0.1Q2 D Yes, the result is the low flow threshold is 0.3Q2 D Yes, the result is the low flow threshold is 0.5Q2 If a geomorphic assessment has been performed, provide title, date, and preparer: Discussion I Additional Information: (optional) Not applicable to the project. 16 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Other Site Requirements and Constraints When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or local codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements. 17 Constraints presented by high density land use eliminated the use of urban green biofilter, vegetated swales, and wetland/wetponds. Use of permeable pavers provided the opportunity to filtrate the runoff into the ground. Optional Additional Information or Continuation of Previous Sections As Needed PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 ' --'' ' '' C ~--~ --Sy C -•s "" -~ ~ 'q ~ ,.,~ ~,--~~ ' Soarce Eomtrol BMl'Eiecldist f fGr;m 1-4 I I Carlsbad BIXIIP IDesign ; : ; for All Be~elopment R12ojeets I Manaal ;, , , ,fitandJHc:tRrojee:ts ana Briod:t1 Be~elogment, i,roj~etsi I' • ' ~~' --~-~-~ ~~-~~""~" ~·==, ==---=~-"-=-~~An --~- Project Identification Project Name: Magnolia Walk Project IID: CT 14-05/ PUID 14-08/ CIDP 14-27 Source Control BMPs All development projects mast implement soarce control BMPs SC-1 throagh SC-6 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP IDesign Manaal for information to implement soarce control BMPs shown in this checklist. Answer each category below parsaant to the following. • "Yes" means the project will implement the soarce control BMP as described in Chapter 4 and/or Appendix E of the Model BMP IDesign Manaal. IDiscassion I jastification is not reqaired. • "No" means the BMP is applicable to the project bat it is not feasible to implement. IDiscassion I jastification mast be provided. • "N/A" means the BMP is not applicable at the project site becaase the project does not inclade the featare that is addressed by the BMP (e.g., the project has no oatdoor materials storage areas). IDiscassion I jastification may be provided. Source Control Requirement Applied? SC-1 Prevention of Illicit IDischarges into the MS4 i:gi Yes lo No lo N/A IDiscassion / jastification if SC-1 not implemented: SC-2 Storm IDrain Stenciling or Signage i:gi Yes lo No lo N/A IDiscassion I jastification if SC-2 not implemented: SC-3 Protect Oatdoor Materials Storage Areas from Rainfall, Ran-On, i:gi Yes lo No lo N/A Ranoff, and Wind IDispersal IDiscassion I jastification if SC-3 not implemented: SC-4 Protect Materials Stored in Oatdoor Work Areas from Rainfall, i:gi Yes lo No lo N/A Ran-On, Ranoff, and Wind IDispersal IDiscassion I jastification if SC-4 not implemented: 18 PIDP SWQMP: Magnolia Walk, Carlsbad PIDP SWQMP Preparation IDate: November 21, 2016 -~Source-~C-ont-ro--1-Requirement-, - SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal Discussion I justification if SC-5 not implemented: SC-6 Additional BMPs Based on Potential Sources of Runoff Pollutants (must answer for each source listed below) 1:2:1 On-site storm drain inlets 0 Interior floor drains and elevator shaft sump pumps 0 Interior parking garages 0 Need for future indoor & structural pest control 1:2:1 Landscape/outdoor pesticide use 0 Pools, spas, ponds, decorative fountains, and other water features 0 Food service 1:2:1 Refuse areas 0 Industrial processes 0 Outdoor storage of equipment or materials 0 Vehicle and equipment cleaning 0 Vehicle/equipment repair and maintenance 0 Fuel dispensing areas O Loading docks 0 Fire sprinkler test water 0 Miscellaneous drain or wash water 1:2:1 Plazas, sidewalks, and parking lots Applied? 0 Yes I O No I O N/ A 0 Yes ONo 0 N/A OYes 0 No 1:2:1 N/A OYes ONo [21 N/A OYes ONo 1:2:1 N/A 1:2:1 Yes ONo ON/A OYes ONo 1:2:1 N/A OYes ONo 1:2:1 N/A 0 Yes ONo 0 N/A OYes 0 No [21 N/A OYes 0 No 1:2:1 N/A OYes ONo [21 N/A OYes ONo 1:2:1 N/A OYes ONo 1:2:1 N/A OYes ONo 1:2:1 N/A 1:2:1 Yes ONo 0 N/A OYes ONo 1:2:1 N/A [21Yes ONo ON/A D_iscussion I ju~t_ific~tion if SC-6 not implemented. Clearly identify which sources of runoff pollutants are discussed. Just1f1cat1on must be provided for all "No" answers shown above. 19 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 ', s '' -, " , , , , , , , , , I ' ' ~+ :~~l w Form 1-5 ' Site mesigm BMR ~f'ie:olUis:t i ' Carlsbad BMP Design for ~II mevelo1mem:t Rrojects I Manual ' 2 ' ,", , , fl~~Jinllanf;:I B~ojeits aJ11~, Rrli~1::it1 11.level~ifallt?.-tti ,f,?l'loieat~J j "' $8 --~--{, 't:l.::...=i ~~'~~-------~~---=--~-~=------~"---------~--~-L -------~ -~ -' Project Identification Project Name: Magnolia Walk Project ID: GT 14-05/ PUD 14-08/ CDP 14-27 Site Design BMPs All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See Chapter 4 and Appendix E of the Model BMP Design Manual for information to implement site design BMPs shown in this checklist. Answer each category below pursuant to the following. • "Yes" means the project will implement the site design BMP as described in Chapter 4 and/or Appendix E of the Model BMP Design Manual. Discussion I justification is not required. • "No" means the BMP is applicable to the project but it is not feasible to implement . Discussion/ justification must be provided. • "N/ A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project site has no existing natural areas to conserve). Discussion/ justification may be provided. Site Design Requirement I Applied? SD-1 Maintain Natural Drainage Pathways and Hydrologic Features I~ Yes ID No ID N/A Discussion I justification if SD-1 not implemented: SD-2 Conserve Natural Areas, Soils, and Vegetation ID Yes I~ No ID N/A Discussion I justification if SD-2 not implemented: The project site has no natural areas to conserve. SD-3 Minimize Impervious Area I~ Yes ID No ID N/A Discussion/ justification if SD-3 not implemented: SD-4 Minimize Soil Compaction I~ Yes ID No ID N/A Discussion I justification if SD-4 not implemented: SD-5 Impervious Area Dispersion I~ Yes ID No ID N/A Discussion I justification if SD-5 not implemented: 20 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Site Design Requirement SD-6 Runoff Collection [2] Yes D N/A Discussion/ justification if SD-6 not implemented: SD-7 Landscaping with Native or Drought Tolerant Species [2] Yes D No D N/A Discussion I justification if SD-7 not implemented: SD-8 Harvesting and Using Precipitation D Yes [2] No D N/A Discussion I justification if SD-8 not implemented: Constraints presented by outburst of Zika virus, vector control, and lack of on-site manager to manage does not not permit harvesting. 21 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 r-1 w ~ ? -"' ~ "' ~~ , ,~ ,-~ 0 s ,,._ 1-m4 I form 1-6 (PDPs) ,, :'' Summary of eme 'Structural BMBs I Carlsbad BMP Design Manual;,,; o/Yt ~~---~----~-----~------~-------= __ [_ -~~ -·--__ " ----~ ~ ---~~ ~ J Project Identification Project Name: Magnolia Walk Project ID: GT 14-05/ PUD 14-08/ CDP 14-27 PDP Structural BMPs All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the selection process described in Chapter 5. PDPs subject to hydro modification management requirements must also implement structural BMPs for flow control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water pollutant control and flow control for hydromodification management can be achieved within the same structural BMP(s). PDP structural BMPs must be verified by the local jurisdiction at the completion of construction. This may include requiring the project owner or project owner's representative and engineer of record to certify construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must be maintained into perpetuity, and the local jurisdiction must confirm the maintenance (see Section 7 of the BMP Design Manual). Use this form to provide narrative description of the general strategy for structural BMP implementation at the project site in the box below. Then complete the PDP structural BMP summary information sheet (page 3 of this form) for each structural BMP within the project (copy the BMP summary information page as many times as needed to provide summary information for each individual structural BMP). Describe the general strategy for structural BMP implementation at the site. This information must describe how the steps for selecting and designing storm water pollutant control BMPs presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated or separate. 22 Constraints presented by high density land use eliminated the use of urban green biofilter, vegetated swales, wetlands/wetponds, harvesting, etc. Use of permeable pave rs provided the opportunity to filterate the runoff into the ground. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Structural BMP Summary Information (Copy this page as needed to provide information for each individual proposed structural BMP} Structural BMP ID No. Construction Plan Sheet No. Type of structural BMP: D Retention by harvest and use (HU-1} D Retention by infiltration basin (INF-1} D Retention by bioretention {INF-2} ~ Retention by permeable pavement {INF-3) D Partial retention by biofiltration with partial retention (PR-1} D Biofiltration (BF-1) D Flow-thru treatment control with prior lawful approval to meet earlier PDP requirements (provide BMP type/description in discussion section below} D Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Flow-thru treatment control with alternative compliance (provide BMP type/description in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: ~ Pollutant control only D Hydromodification control only D Combined pollutant control and hydromodification control D Pre-treatment/forebay for another structural BMP D Other (describe in discussion section below) Who will certify construction of this BMP? Provide name and contact information for the party responsible to sign BMP verification forms if required by the City Engineer (See Section 1.12 of the BMP Design Manual) Who will be the final owner of this BMP? Who will maintain this BMP into perpetuity? What is the funding mechanism for maintenance? 23 Tony Sfreddo 29250 Paseo Sedano San Juan Capistrano, CA 92675 (951) 801-0888 TMS Highland Investments, LLC TMS Highland Investments, LLC Funds collected by HOA from property owners. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Attachment Sequence Attachment la Attachment lb Attachment le Attachment ld Attachment le 24 ATTACHMENT 1 BACKUP FOR PDP POLLUTANT CONTROL BMPS This is the cover sheet for Attachment 1. Indicate which Items are Included behind this cover sheet: Contents DMA Exhibit (Required) See DMA Exhibit Checklist on the back of this Attachment cover sheet. Tabular Summary of DMAs Showing DMA ID matching DMA Exhibit, DMA Area, and DMA Type (Required)* *Provide table in this Attachment OR on DMA Exhibit in Attachment la Form 1-7, Harvest and Use Feasibility Screening Checklist (Required unless the entire project will use infiltration BMPs) Refer to Appendix B.3-1 of the BMP Design Manual to complete Form 1-7. Form 1-8, Categorization of Infiltration Feasibility Condition (Required unless the project will use harvest and use BMPs) Refer to Appendices C and D of the BMP Design Manual to complete Form 1-8. Pollutant Control BMP Design Worksheets I Calculations (Required) Refer to Appendices Band E of the BMP Design Manual for structural pollutant control BMP design guidelines Checklist ~ Included ~ Included on DMA Exhibit in Attachment la D Included as Attachment lb, separate from DMA Exhibit D Included ~ Not included because the entire project will use infiltration BMPs ~ Included D Not included because the entire project will use harvest and use BMPs ~ Included PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Use this checklist to ensure the required information has been included on the DMA Exhibit: The DMA Exhibit must identify: ~ Underlying hydrologic soil group ~ Approximate depth to groundwater ~ Existing natural hydrologic features (watercourses, seeps, springs, wetlands) D Critical coarse sediment yield areas to be protected ~ Existing topography and impervious areas ~ Existing and proposed site drainage network and connections to drainage offsite ~ Proposed demolition ~ Proposed grading ~ Proposed impervious features ~ Proposed design features and surface treatments used to minimize imperviousness ~ Drainage management area (DMA) boundaries, DMA ID numbers, and DMA areas (square footage or acreage), and DMA type (i.e., drains to BMP, self-retaining, or self-mitigating) ~ Potential pollutant source areas and corresponding required source controls (see Chapter 4, Appendix E.1, and Form l-38) ~ Structural BMPs (identify location, type of BMP, and size/detail) 25 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 I /I II/ I I I; 'I I; I I; I I; '/ I; k---I; 1/ ''1; I I; I I; I I; L I; ,'/'\' Y; I Y; I I; I I; I I; I'/ /~8.J6 TC j 57.89 FL '/ I; I I; '/ I; ; (!r-S-IT_E _E-NT_R_ri~~l I; f; I /; f 0/ ~ .... ~t:t I ft "'i}/1 ~~ R. .;?' {}o·/ . .;;; t t;:,J? I t I ;;j(t; tiL \" I ~~1~~11fl· . · ' y l"\j) ~1)6, / ' ''--·M &."z I ~} I . ,,µ...L....,L.L..·-<-""-"-''---"-'-../ { cu1rs i~ .J. i' . . /· sf "'a ·Oo, · . '3;tz '/.J0:1r1 ~' • ;;"'"0~~ -;-34. 7~ I;--?~1""""""'i,,,;;ma..:;.ta~"""""-'""""'".._.. o(j ' /; ~ ~~~ 't-JEFFERSON ST 59.57 ~IM ~ 49.01)\NV I 10+00 JEFFERSON ST= S4#1 10+00 MAGNOLIA AVE # I j I )~ I I ,s SWQMP NO. 16-03 ~~~~~~~~~ MAINTENANCE AGREEMENT DOCUMENT: YES ../ NO RECORDATION NO. ____ _ PARTY RESPONSIBLE FOR MAINTENANCE: NAME: IMS HIGHLAND INVESTMENTS LLC CONTACT: TONY SFREDDO PLAN PREPARED BY: NAME: SURENDER DEWAN COMPANY: PMS CONSULTANTS INC ADDRESS: 12371 LE\\1S ST., SUITE 203 GARDEN GROVE, CA 92840 j I ADDRESS: 29250 PASEO SEDANO PHONE NO.: 714-740-8840 CERTIFICATION: R.C.E. 34559 j I ·::,110,. I ~6· 1A •• SAN JUAN CAPISTRANO. CA 92675 PHONE NO: 951 801 0888 ~ w,v-"' ~~~~-:,:,i:,:,j~1~7 v v v v v --''Sv v v v v v ~r~ 'v V V 'v V vvvvvvv VVVVVv'V rr;Jd:r,-..,,.."'l""v v v v v v v v v v v v v v v v v v vvvi~~vvvy vvv~~~vvvv v v v ~a.1:_lp)fo v v v v v v '7~ll.1fpAfl v v v v vvvvvvvvvv vvvvvvvvvv v v v v v v v v v v WV-V-V-'v'l PROPOSED SOUND WALL V V V V V V V V vvvvvvvvvv V 'v V V V V V V V V v _'y_ V v_y V V V V V V V V V V 9 'v·V-'v .. "v_ vvvvvvvvvv 'v 'v V V V V V V V 'v vvvvvvvvvv V V V5!}7.51S'7.Gr:l 'v V V V v v v 071.,l'JF1i\Cv v v v vvvvvvvvvv VVVVVVVV7V vvvvvvvv1v V V V V V V V 'v<..'9 V v v v v v v v v fl'v v vvvvvvvvvv v'-Y,V V V V V V V V V VVVVV'v'v'v'vV V V V V V V V V V V 'v V V V 'v ·9 V V V V V V V V V vS~vSG~BfV V V V V V V ·ry SJ.fjjF'o/lC9 V V vvvvv;vvvvvv vvvvvvvvvv vvvvvvvv VVVVVYVVVV vvvvvvvvvv vvvvvvvvvv vvvvvvvvvv V V 'v V V V 'v V V 'v vvvvvvvvvv vvvvvvvvvv V V V :78.'JQ\Y(fV V V v v V v5pg:jpii() v V V V 'v V V V V V V V V V 'v V V V V V V V "O I~ "" 0 "O 0 V, I~ 8 I~ V, 0 I C I z C, I ~ I r r 0 I z I H- I :c i5 :c "' M ,;! z z "' ~ r r 1§§~ V V V V V 'v V V 'v V 1,--,117 v v v v v v v v v vvvvvvvvvv vvvvvvvvvv 11"'"""~ V v' V V V V V 'v 'v V v v v v v v7x>0'3Ft'7 v v v V V V V V5¥.6'0P)Z0 V V V V vvvvvvvvvvvv vvvvvvvvvvvv ~:;=;=,;j::::;;::,=;;=;,f7 v v v v v v v v v v v v vvvvvvvvvvvv v v v v %8-B'J:V v v '7 v v V V V V v573~r>,\9 V V V V vvvvvvvvvvvv ~~~L'V V V V V V V V V V V V lli'n '2 V V V V V V V v v v BMP ID# BMP TYPE TREATMENT CONTROL ,;-;,IA PERMEABLE '0) PAVEMENT (INF-3) MANF. BY UNI-ECOSTONE r;;:;,lB PERMEABLE 'el PAVEMENT (INF-3) MANF. BY UNI-ECOSTONE HYOROMOOIFICA TION SOURCE CONTROL CATCH BASIN STENCILING SITE DESIGN AND LANDSCAPE PLANTING COMMON AREA EFFICIENT IRR. COMMON AREA ROOF RUNOFF 1RASH ENCL. f, ,, BMP TABLE SYMBOL CASQA NO. QUANTITY DRAWING NO. SHEET NO.(S) I ™ SD-20 1370 SF. 490-4A 2 ™ S0-20 864 SF. 490-4A 2 -----EXCEMP D ------- mIDI 3 EA. 490-4A 2 w~ SD-10 ~,../1 SD-12 ...... ., .. .,., .. "" "" .. 7 """"""" SD-11 LJLJ SD-32 1 EA. 490-4A 2 INSPECTION FREQUENCY ONCE A YEAR ONCE A YEAR MAINTENANCE FREQUENCY PERIODIC CLEANING AND VACCUM CLEANING 11-lE SURFACE ATLEAST ONCE A YEAR PERIODIC CLEANING AND VACCUM CLEANING THE SURFACE ATLEAST ONCE A YEAR PERIODICAL Y. AS RESTENCIL IF ILLWBLE REQUIRED DRAINAGE MANAGEMENT AREA (DMA) TABLE CONSTRUCTION SIGN OFF BMP AREA BMP TYPE DESCRIPTION AREA (ACRE) VOLUME (CF) (REQUIRE'.D) VOLUME (CF) FLOW CAPACITY (CFS) FLOW CAPACITY (CFS) (PROVIDE'.D) (REQUIRED) (PROVIDED) A INFILTRATION PERMEABLE PAVERS 0.34 338 1370 B INFILTRAllON PERMEABLE PAVERS 0.29 284 864 CONSTRUCT SOUND WALL ON ±1' HIGH RETAINING WALL BOTIOM OF GRAVEL TO BE LAID FLAT AT AN ELEVATION OF 56.10 V V V V V V V V V V V ':,,;e-·-o1. v v v v v v v v V v V V V V V V V V V V % V 'v\ V (:.)/ r:V 0~ V A;v; J1 nV v v v v v v v v v v v ~ v "-'I; ,zC'fi'"'zM.v,Nv pv,f/7 V V V V V V V V V V :% V V V ~~~t' {)t:)€, V V V vvvvvvvv~vv~ vvvvvvvvvv V V V 'v 'v 'v V V V V l!='=r---l'=c'jly V V V V V V V V V vvvvvvvvvvv vvvvvvvvvv vvvvvvvvvv vvvvvvvvvv vvvvv~~~vvvvv vvvv~~~~vvvv v v v v 'i/6Y63:7A&' v v v v v v v v v ::.l'.>./l'Jf'\'ILv v v v vvvvvvvvvvvvv vvvvvvvvvvvv vvvvvvvvvvvv vvvvvvvvvvvv vvvvvvvvvvvv VVVVV'vVVVVVVV v v v v5%,CB,c-rv v v v v v V V V V ~7.~3~\lv V V 'v 'v V vvvvvvvvvvvv vvvvvvvvvvvvv V v v v v v v V v V ~a~ V V V V V 'v V V V V V V vvvvvvvv y5(1;,0\!fFv v v v v '§ii. V3~AC'y v 7 v v vvvvvvvvvvvv vvvvvvvvvvvv Pl'ai¥2v v v v v v v v v v vvvvvvvvvv v v v v v v v v v v ,qfr:=::il V V V V V V V V V V 11~31; vvvvvvvvvv'vj V V V V V V V V V V •e----JI/ vvvvvvvvvv vvvvvvvvvv v v v v v v v v v v .'1!."""'elj v v v v 'ii7,<i0':l'rf\7 v v v v v v v v v5""8ii'Pi?Jv v v v v vvvvvvvvvvvv .jt ~ r:~ j!// ~ ,I Jr ~ 3 3 "1// jir " ~s~ 4 4 ~ CONSTRUCT SOUND WALL ON ±2' HIGH RETAINING WALL CONSTRUCT SOUND WALL ON ±3' HIGH RETAINING WALL r-(/ r-~--"Ei?-----''-"-~~~~~~~~~~-~-----"-"'-"'-=""---"'~_=,'-"'-'-=-'-='---'~~~-~~~-~-~------'s.:..L-~~~~-~~--~-1------~-------~--___:~~~~~!':!.2::~~~~~----~------~---~~ 57. 73)TC ,?' ji 0' I/;;· f»., I/'-' 0 II -"" "' & // II ~ p ) I ' II II LEGEND LANDSCAPE AREAS WITH BMP's: (MAINTAINED BY PROPERTY OWNER/HOA) TRACT BOUNDARY DIRECTION OF ONSITE SURFACE FLOW • •.. DIRECTION OF OFFSITE SURFACE FLOW PERMEABLE CONC. PAVERS DMA BOUNDARIES NOTE: ALL ROOF DRAINS SHALL DRAIN TO PERMEABLE INTIERLOCKING CONG. PAVERS OR PLANTING AREAS. ROOF DRAINS SHALL NOT CONNECT DIRECTLY TO THE STORM DRAIN SYSTEM BMP NOTES: 1. THESE BMPS ARE MANDATORY TO BE INSTALLED PER MANUFACTURER'S RECOMMENDATIONS OR THESE PLANS. 2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPES OR PLANTING TYPES WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY INSPECTION STAFF HAS INSPECTED THIS PROJECT FOR APPROPRIA TIE BMP CONSTRUCTION AND INSTALLATION. HYDROLOGIC SOIL GROUP -"B" APPROXIMATE DEPTH OF GROUND WATER -GREATER THAN 12 FEET EXISTING NATURAL HYDROLOGIC FEATURES -NONE CRITICAL COARSE SEDIMENT YIELD AREAS -NONE STRUClURAL BMPs: (SEE GRADING PLAN FOR LOCATION AND DETAILS) PERMABLE PAVEMENT -BMP 1 (INF-3) VERIFIED BY: INSPECTOR ENGINEERING DEPARTMENT DATE SHEETS of 1 l------+---1------------1--+---+----+----t I SH1EET I CITY OF CARLSBAD ~B~M~P=S~l~TE~P~LA=N;;:::;F~O~R=,================::::'_':====~ MAGNOLIA WALK ENGINEER DMS 763 AND 749 A & B MAGNOLIA AVENUE, CARLSBAD, CA 92008 APPROVED: JASON GELDERT SCALE: 1"=10' ~C~O~N~S~U=--=L~T~A~N"='-'T~S~,=-'=IN~C=--=·t-----t---t---,,---------------t---J----t------t----'-1~C=ITY==EN~G=IN=EE=R=P=E=6~39~12====E=XP=IR=E=S=09:::'.:::30:::'.:::16==-;:::===D=A=TIE~ g,1~ewis";t.JQ)trdenG~wc"!ne':P.~4-:-&l!F.1;;4-7!-61J~ l---=-c=+==-+J..1'-'-------------------+---1---lf----+----l OWN BY: NC PROJECT NO. DRAWING NO. DATE INITIAL DATE INITIAL DATE INITIAL CHKD BY: --CT-14-05 490-4A RVWD BY: EXP. 9/30/17 ENGINEER OF WORK REVISION DESCRIPTION SURENOER M. Dt;W'AN RCE ~4009 OTHER APPROVAL CITY APPROVAL ~ " ~' -' ~:; " " ~ ' -~-? -;c ' ~ f" i Form 1-8 1 '. lategorization of Infiltration FeasilDilitt monaition ' , --------------------' -------~------' -------------~---~ Part 1-Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria 1 Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Yes No D Provide basis: See attached Infiltration report prepared by StrataTech, Inc. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. D Provide basis: There are no nearby slopes in the project area. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 26 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 "7 ,-~ "'~ "' "' "" -~ "' -fitrm :, liOl'lnl 1-1 Rag~ I of a. :1' Criteria 3 ~-~--------------~------------J!l Screening Question Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Yes No D Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. D Provide basis: Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability. Part 1 Result * If all answers to rows 1-4 are "Yes" a full infiltration design is potentially feasible. The feasibility screening category is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 [81 Yes D No *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. 27 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Part 2 -Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Screening Question Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Not Applicable. Yes No D D Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. D D Provide basis: Not Applicable. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 28 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 0 "' ,,, ',, ,,, ,-' ''" ' E '""]'ij Seim 1-1 R,age I el I , , ti ----' ' ' "'' -~' Criteria 7 Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: Not Applicable. Yes No D D Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix Provide basis: Not Applicable. D D Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 If all answers from row 5-8 are yes then partial infiltration design is potentially feasible. The feasibility screening category is Partial Infiltration. Result* If any answer from row 5-8 is no, then infiltration of any volume is considered to be infeasible within the drainage area. The feasibility screening category is No Infiltration. D Yes D No *To be completed using gathered site information and best professional judgment considering the definition of MEP in the MS4 Permit. Additional testing and/or studies may be required by Agency/Jurisdictions to substantiate findings. 29 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 1 2 3 4 5 6 1 2 3 4 5 6 30 Drainage Management Area A 35th percentile 24-hr storm depth from figure 8.-1 d= 0.60 inches Area tributary to 8MPs A= 0.34 acres Area weighted runoff factor (estimate using Appendix 8.1-1 and 8.2-1) C= 0.45 unitless Tree wells volume reduction TCV= 0 cubic-feet Rain barrels volume reduction RCV= 0 cubic-feet Calculate DCV = (3630 x C x d x A) -TCV -RCV DCV= 338 cubic-feet Drainage Management Area B 35th percentile 24-hr storm depth from figure 8.-1 d= 0.60 inches Area tributary to 8MPs A= 0.29 acres Area weighted runoff factor (estimate using Appendix 8.1-1 and 8.2-1) C= 0.45 unitless Tree wells volume reduction TCV= 0 cubic-feet Rain barrels volume reduction RCV= 0 cubic-feet Calculate DCV = (3630 x C x d x A) -TCV -RCV DCV= 284 cubic-feet PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 1 2 3 4 5 6 1 2 3 4 5 6 31 Drainage Management Area A DCV (Worksheet B.2-1) DCV= 338 cubic-feet Estimated design infiltration rate {Form 1-9 in Appendix I) Kdesign= 1.56 in/hr Available BMP surface area ABMP= 1,370 sq-ft Average effective depth in the BMP footprint (DCV/AsMP) Davg= 0.25 feet Drawdown time, (Davg *12/Kciesign) T= 0.16 hours Provide alternative calculation of drawdown time, if needed. N/A Drainage Management Area B DCV (Worksheet B.2-1) DCV= 284 cubic-feet Estimated design infiltration rate (Form 1-9 in Appendix I) Kdesign= 1.56 In/hr Available BMP surface area ABMP= 864 sq-ft Average effective depth in the BMP footprint (DCV/AsMP) Davg= 0.32 feet Drawdown time, (Davg *12/Kciesign) T= 0.20 hours Provide alternative calculation of drawdown time, if needed. N/A PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 32 ---, Factor of-Saf~t,~~mc/aesig~ lmfil~~~~iom -R~;e I -"' --~ '0 0:ifi ' Woris~eet / Form 1-9 -~-------~--~------~------I Assigned Factor Product (p) Factor Category Factor Description Weight (w) Value (v) p=wxv Soil assessment methods 0.25 3 0.75 Predominant soil texture 0.25 1 0.25 Suitability Site soil variability 0.25 1 0.25 A Assessment Depth to groundwater I impervious layer 0.25 2 0.50 Suitability Assessment Safety Factor, SA= mp 1.75 Level of pretreatment/ expected sediment loads 0.5 3 1.50 B Design Redundancy/resiliency 0.25 3 0.75 Compaction during construction 0.25 3 0.75 Design Safety Factor, SB = mp 3.00 Combined Safety Factor, stotal= SAX SB 3 X 1.75 = 5.25 Observed Infiltration Rate, inch/hr, Kabserved 8.20 in/hr (corrected for test-specific bias) Design Infiltration Rate, in/hr, Kciesign = Kobserved / S101a1 1.56 in/hr Supporting Data Briefly describe infiltration test and provide reference to test forms: Infiltration test performed by StrataTech, Inc. included on following page. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 •.. Ji•iif"~J,,,~,ST RATA·T EC H, INC. ~·· i?':7' -G E D C D N S U LT A N TS 714-521-5611 562-427-8099 FAX 714-521-2552 7372 Walnut Avenue, Unit F ,Buena Park, California 90620 December 9, 2014 DS Products, Inc. Tony S:freddo 24 Amber Leaf Irvine, California, 92614 Gentlemen: Subject: W.0.273114 Percolation Infiltration testing, Storm Water Management, 749-763 Magnolia Dr., Carlsbad, California Reference: Preliminary Geotechnical Engineering Investigation, Proposed Multi Family Residential Development, 749-763 Magnolia Drive, Carlsbad, California. In accordance with your authorization and terms of our contract STRATA-TECH, Inc. is pleased to submit the results of our storm water infiltration testing. Percolation testing was performed in two borings at the locations shown on the attached site plan. The soils encountered consist of Sand, fine, trace of clay, and Sand fn-med dense dry to the depth of 12-feet. The percolation boring depth was governed by the understanding groundwater will be on the order of 20 feet below finished grade. Testing was performed in 5-foot dry percolation borings consisting of 4-inch slotted well screen with .020 "openings in 6-inch diameter borings having the annular space packed with #3 Monterey filter sand. The testing consisted of filling the percolation boring with water to within 0.5-foot of the surface and allowing it to seep till dry and repeatedly filling the test borings and measuring the stabilized STRATA·TECH,INC. GEOCONSULTANTS DS Products, Inc Storm Water Percolation Testing 2 December 9, 2014 749-763 Magnolia Dr, Carlsbad, CA rate. The rates for the drop between the 4th and 5th foot was measured in each boring and are the basis for the design rate of 8.2 Inch/Hr. The design infiltration rate of 8.2 Inch/Hr. may be used by the design civil engineer for the infiltration system for the subject site. At the completion of testing the well screens were pulled and remaining holes filled native soils. The work performed was carried out in accordance with acceptable geotechnical principles common to the local area in which we practice. We make no other warranties, either expressed or implied. We appreciate this opportunity to be of service to you. R.o]ruld Acuna. PG President umyf.in!ey RCl:46606 ATIACHMENT2 BACKUP FOR PDP HVDROMODIFICATION CONTROL MEASURES This is the cover sheet for Attachment 2. t8J Mark this box if this attachment is empty because the project is exempt from PDP hydromodification management requirements. Attachment Sequence Attachment 2a Attachment 2b Attachment 2c Attachment 2d Attachment 2e 33 Indicate which Items are Included behind this cover sheet: Contents Checklist Hydromodification Management Exhibit D Included (Required) See Hydromodification Management Exhibit Checklist on the back of this Attachment cover sheet. Management of Critical Coarse Sediment D Exhibit showing project Yield Areas (WMAA Exhibit is required, drainageboundaries marked on additional analyses are optional) WMAA Critical Coarse Sediment Yield Area Map (Required) See Section 6.2 of the BMP Design Manual. Optional analyses for Critical Coarse Sediment Yield Area Determination D 6.2.1 Verification of Geomorphic Landscape Units Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite Geomorphic Assessment of Receiving D Not performed Channels (Optional) D Included D Submitted as separate stand- See Section 6.3.4 of the BMP Design alone document Manual. Flow Control Facility Design, including D Included Structural BMP Drawdown Calculations D Submitted as separate stand- and Overflow Design Summary alone document (Required) See Chapter 6 and Appendix G of the BMP Design Manual Vector Control Plan (Required when D Included structuralBMPs will not drain in 96 hours) D Not required because BMPs will drain in less than 96 hours PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Use this checklist to ensure the required information has been included on the Hydromodification Management Exhibit: The Hydromodification Management Exhibit must identify: D Underlying hydrologic soil group D Approximate depth to groundwater D Existing natural hydrologic features (watercourses, seeps, springs, wetlands) D Critical coarse sediment yield areas to be protected D Existing topography D Existing and proposed site drainage network and connections to drainage offsite D Proposed grading D Proposed impervious features D Proposed design features and surface treatments used to minimize imperviousness D Point(s) of Compliance (POC) for Hydromodification Management D Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) D Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) 34 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Attachment Sequence Attachment 3a Attachment 3b 35 ATTACHMENT 3 Structural BMP Maintenance Information This is the cover sheet for Attachment 3. Indicate which Items are Included behind this cover sheet: Contents Checklist Structural BMP Maintenance Thresholds ~ Included and Actions (Required) See Structural BMP Maintenance Information Checklist on the back of this Attachment cover sheet. Draft Maintenance Agreement (when ~ Included applicable) D Not Applicable PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Use this checklist to ensure the required information has been included in the Structural BMP Maintenance Information Attachment: D Preliminary Design I Planning I CEQA level submittal: Attachment 3a must identify: D Typical maintenance indicators and actions for proposed structural BMP(s) based on Section 7.7 of the BMP Design Manual Attachment 3b is not required for preliminary design I planning/ CEQA level submittal. ~ Final Design level submittal: 36 Attachment 3a must identify: ~ Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7.7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s) ~ How to access the structural BMP(s) to inspect and perform maintenance ~ Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds) D Manufacturer and part number for proprietary parts of structural BMP(s) when applicable ~ Maintenance thresholds specific to the structural BMP(s), with a location-specific frame of reference (e.g., level of accumulated materials that triggers removal of the materials, to be identified based on viewing marks on silt posts or measured with a survey rod with respect to a fixed benchmark within the BMP) ~ Recommended equipment to perform maintenance D When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Attachment 3A -BMP Maintenance Thresholds for Permeable Pavers Typical Maintenance lndicator(s) for Permeable Pavers Standing water in permeable paving area Damage to permeable paving surface Maintenance 37 Maintenance Actions Flush fine sediment from paving and subsurface gravel. Provide routine vacuuming of permeable paving areas to prevent clogging. Repair or replace damaged surface as appropriate. Vacuum clean the surface at least once a year to remove sediment from openings to regenerate infiltration. Vacuum settings may require adjustment to prevent uptake of aggregate in the pavement openings and joints. The surface should be dry when cleaning. PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Appendix I: Forms and Checklists RECORDING REQUESTED BY: WHEN RECORDED MAIL TO: (property owner) SP ACE ABOVE THIS LINE FOR RECORDER'S USE MAINTENANCE NOTIFICATION AGREEMENT FOR CATEGORY 1 · STORMWATER STRUCTURAL BM P's THIS AGREEMENT is made on the ________ day of , 20 __ . ----------------------' the Owner(s) of the hereinafter described real property: Address ____________________ Post Office Zip Code __ _ Assessor Parcel No.(s>--------------------------------- List, identify, locate (plan/drawing number) and describe the Structural Owner(s) of the above property acknowledge the existence of the storm water Structural Best Management Practice on the said property. Perpetual maintenance of the Structural BMP(s) is the requlrement of the State NPDES Permit, Order No. R9-2015-0001, Section E.3.e.(1)( c) and the County of San Diego Watershed Protection Ordinance (WPO) Ordinance No. 10385 Section 67.812 through Section 67.814, and County BMP Design Manual (BMP OM) Chapters 7 & 8. In consideration of the requirement to construct and maintain Structural BMP(s), as conditioned by Discretionary Permit, Grading Permit, and/or Building Permit (as may be applicable), I/we hereby covenant and agree that: 1. I/We are the owner(s) of the existing (or to be constructed concurrently) premises located on the above described property. 2. I/We shall take the responsibility for the perpetual maintenance of the Structural BMP(s) as listed above in accordance with the maintenance plan and in compliance with County's self-inspection reporting and verification for as long as I/we have ownership of said property(ies). 3. I/We shall cooperate with and allow the County staff to come onto said property(ies) and perform inspection duties as prescribed by local and state regulators. 4. I/We shall inform future buyer(s) or successors of said property(ies) of the existence and perpetual maintenance requirement responsibilities for Structural BMP(s) as listed above and to ensure that such responsibility shall transfer to the future owner(s). 5. I/We will abide by all of the requirements and standards of Section 67.812 through Section 67.814 of the WPO (or renumbering thereof) as it exists on the date of this Agreement, and which hereby is incorporated herein by reference. This Agreement shall run with the land. If the subject property is conveyed to any other person, firm, or corporation, the instrument that conveys title or any interest in or to said property, or any portion thereof, shall contain a provision transferring maintenance responsibility for Structural BMP(s) to the successive owner according to the terms of this Agreement. Any violation of this Agreement is grounds for the County to impose penalties upon the property owner as prescribed in County Code of Regulatoiy Ordinances, Title 1, Division 8, Chapter 1 Administrative Citations §§18.101-18.116. Owner(s) Signature(s) Print Owner(s) Name(s) and Title STATE OF CALIFORNIA COUNTY OF __________ ~ On before me, Notary Public, personally appeared who proved to me on the basis of satisfactory evidence to be the person(s) whose name(s) is/are subscribed to the within instrument and acknowledged to me that he/she/they executed the same in his/her/their authorized capacity(ies), and that by his/her/their signature(s) on the instrument the person(s) or the entity upon behalf of which the person(s) acted, executed the instrument. I certify under PENAL TY OF PERJURY under the laws of the State of California that the foregoing paragraph is true and correct. WITNESS my hand and official seal. 1-13 February 26, 2016 ATIACHMENT4 Single-Sheet BMP (SSBMP) Plan This is the cover sheet for Attachment 4. Use this City Template SSBMP Plan (see city website for most recent version) Use this checklist to ensure the required information has been included on the SSBMP plan: The plans must identify: [gJ Structural BMP(s) with ID numbers matching Form 1-6 Summary of PDP Structural BMPs [gJ The grading and drainage design shown on the plans must be consistent with the delineation of DMAs shown on the DMA exhibit [gJ Details and specifications for construction of structural BMP(s) [gJ Signage indicating the location and boundary of structural BMP(s) as required by the City Engineer [gJ How to access the structural BMP(s) to inspect and perform maintenance [gJ Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds) [gJ Manufacturer and part number for proprietary parts of structural BMP(s) when applicable [gJ Maintenance thresholds specific to the structural BMP(s), with a location-specific frame of reference (e.g., level of accumulated materials that triggers removal of the materials, to be identified based on viewing marks on silt posts or measured with a survey rod with respect to a fixed benchmark within the BMP) [gJ Recommended equipment to perform maintenance [gJ When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management [gJ Include landscaping plan sheets showing vegetation requirements for vegetated structural BMP(s) [gJ All BMPs must be fully dimensioned on the plans [gJ When proprietary BMPs are used, site-specific cross section with outflow, inflow, and model number shall be provided. Photocopies of general brochures are not acceptable. 38 PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 39 HYDROMODIFICATION EXEMPTION REPORT PDP SWQMP: Magnolia Walk, Carlsbad PDP SWQMP Preparation Date: November 21, 2016 Chang~ Civil Engineering•Hydrology-Hydraulics•Sedimentation May 3, 2016 Tony Sfreddo TMS Highland Investments, LLC 2967 Michelson Drive, Suite G-662 Irvine, CA 92612 Subject: 749 Magnolia Avenue Hydromoditication Exemption Dear Tony: P.O. Box 9496 Rancho Santa Fe, CA 92067-4496 T: 858.692.0760 F: 656.832.1402 wayne@changconsultants.com This letter provides documentation in support of a hydromodification exemption for your proposed 16-unit townhome development at 749 Magnolia Avenue in the city of Carlsbad. The project site is located on the south side of Magnolia Avenue approximately midway between Jefferson Street and Madison Street. The site currently contains residential development that will be demolished for the project. Chang Consultants prepared the September 17, 2015 report, Hydromodi.fication Exemption Analyses for Select Carlsbad Watersheds, that identified several areas including the project site as being exempt from hydromodification. The exemption was based on the City of Carlsbad's Municipal Permit regulations and their recent 2016 Carlsbad BMP Design Manual. The exemption criteria cited in the 2015 report identified areas where runoff from a project is either conveyed by storm drains or conveyance channels (i.e., non-erodible drainage facilities) directly to enclosed embayments (e.g., a lagoon). My understanding is that the City of Carlsbad is in the process of seeking approval for the 2015 report from the San Diego Regional Water Quality Control Board. In the interim, the City indicated that a site specific assessment could be performed to exempt your project. . The site specific assessment is as follows. Storm runoff from the project site is directed onto Magnolia A venue along the project frontage. There is essentially no off-site run-on to the project site. The runoff is conveyed westerly along Magnolia Avenue approximately 700 feet. Magnolia Avenue turns to the northwest and becomes Roosevelt Street. Magnolia Avenue and Roosevelt Street are fully improved with concrete curb, gutter, and sidewalk. The runoff continues approximately 720 feet northwest in Roosevelt Street to Chestnut A venue, which is a cross-street. The runoff flows around the curb return, then continues southwesterly in Chestnut A venue nearly 500 feet to a cul-de-sac. Chestnut Avenue is constructed to its full width and contains a combination of either concrete curb, gutter, and sidewalk or asphalt curb. The runoff enters an underground storm drain in the Chestnut Street cul-de-sac. The relevant storm drain as-built sheets (drawing no. 360-5) are attached. Sheet 9 contains the storm drain along the cul-de-sac, and shows a Type B curb inlet within the cul-de-sac to capture the above described street flow. The profile indicates that the 100-year storm drain flow approaching the curb inlet is 259 cubic feet per second (cfs), while the flow below the inlet is 262 cfs. Based on this, the 100- year surface flow in the street is relatively small and can be conveyed along the streets from the site and cul-de-sac without causing hydromodification impacts. Note that hydromodification is based on the 2-to l 0-year storm event, not the 100-year event provide on the plans, so if the drainage system has capacity for the l 00-year flows it will have capacity for the lower hydromodification flows. The runoff continues in the storm drain towards the railroad tracks just southwest of Chestnut A venue. The as-built drawings show that the storm drain then parallels the east side of the railroad and continues southeasterly to a discharge point at the Agua Hedionda Lagoon. The hydraulic grade line is included on the as-builts and shows that the 100-year flow is contained below the ground surface. In addition, the riprap energy dissipater at Agua Hedionda Lagoon extends below low tide level in Agua Hedionda Lagoon. Consequently, the hydromodification flows will be contained in the storm drain system and have adequate energy dissipation at the outlet into the lagoon. This information verifies that the 10-year hydromodification flows from the project site will be contained within either non-erodible conveyance channels (streets and curbs) or storm drains to an enclosed embayment. Therefore, the project will not cause hydromodification impacts and qualifies for a hydromodification exemption. Sincerely, Wayne W. Chang, M.S., P.E. 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