Loading...
HomeMy WebLinkAboutCT 14-09; UPTOWN BRESSI RANCH; PRELIMINARY STORM WATER MANAGEMENT PLAN; GPA 14-04, MPA 178I, CT 14-09, PUD 14-10, SDP 14-13, SDP 16-06, CUP 14-09, CUP 16-01, EIR 15-01, LFMP 87-17A; 2016-01-22RECORD COPY I -PE/I.. 2/J/,~' PRELIMINARY Initial DatSTO. M WATER MANAGEMENT PLAN ---· FOR BRESSI RANCH (LOTS 29 THRU 32) (PRELIMINARY ENGINEERING) PUD 14-10, SDP 14-13 GPA 14-04, MP 178(1), CT 14-09 Job Number 17169 November 24, 2014 Revised: March 25, 2015 Revised: January 22, 2016 RICK ENGINEERING COMPANY rickengineering.com ·-,._I : J ·, .. J , __ J PRELIMINARY STORM WATER MANAGEMENT PLAN FOR BRESSI RANCH LOTS 29 THRU 32 (PRELIMINARY ENGINEERING) PUD 14-10, SDP 14-13 GPA 14-04, MP 178(1), CT 14-09 Job Number 17169 Brendan Hastie R.C.E. #65809 Exp. 09/17 Prepared For: Sarah 1\101:rell (Owner) Shea Homes 9900 Mesa Rim Road San Diego, California 92121 Prepared By: Kevin ~cCook (Owner) Shea Business Properties 9900 Mesa Rim Road San Diego, California 92121 Rick Engineering Company 5620 Friars Road San Diego, California 92110-2596 (619) 291-0707 November 24, 2014 Revised: March 25, 2015 Revised: January 22, 2016 ~,-} L_J l I ···-J t .J LJ TABLE OF CONTENTS Revision Page-dated January 22, 2016 .................... : ................................................................................................... i Revision Page -dated March 25, 2015 ......................................................................................................................... ii 1.0 Introduction ................................................................................................................................ l 2.0 Identification of Pollutants and Conditions of Concern .......................................................... .4 3.0 Selection of Treatment Control BMPs ..................................................................................... 8 4.0 Hydromodification Study and Findings .................................................................................. 12 5.0 Drainage Study ....................................................................................................................... 22 6.0 Integrated Low Impact Development Design Strategies ........................................................ 23 7.0 Documentation of Drainage Design ....................................................................................... 27 8.0 Source Control Measures ........................................................................................................ 28 9.0 Operation and Maintenance .................................................................................................... 30 10.0 SWMP Certification Statements ........................................................................................... 37 Figures: F. 1' v· .. M . 3 1gure : 1c1n1ty ap ................................................................................................................ .. Tables: Table 2-1: Anticipated and Potential Pollutants Generated by Land Use Type .............................. 5 Table 3-1: Structural BMP Treatment Control Selection Matrix .................................................... 9 Table 4-1: Hydromodification Management Plan (HMP) POC-2 Exemption Results ................. 16 Table 4-2: Summary of Hydromodification Management Plan (HMP) Results ........................... 20 Table 6-1: Grouping of Potential Pollutants of Concern by Fate during Stormwater Treatment.24 Table 6-2: Groups of Pollutants and Relative Effectiveness of Treatment Facilities ................... 25 Table 8-1: Permanent and Operational Source Control Measures ................................................ 28 Table 9-1: Summary Table oflnspection and Maintenance Frequency ....................................... 35 Prepared By: Rick Engineering Company-Water Resources Division BH:SR:vs/Repmt/17169.006 11-24-14 Revised:3-25-15 Revised: 1-22-16 L •.. J "-.~.} .! Appendices: Appendix A: City of Carlsbad Storm Water Standards Questionnaire (SWSQ) Appendix B: Hydrologic Unit Map and 2010 303(d) List Appendix C: Water Quality Treatment and HMP Calculations Appendix D: Details for TC-BMPs and HM-BMPs Appendix E: Storm Water Management Model (SWMM) Results and Supporting Materials/Exhibit Appendix F: Drawdown Time Calculations Appendix G: Potential Critical Coarse Sediment Yield Exhibit Appendix H: Feasibility Worksheets for Infiltration and Harvest & Use Appendix I: Summary of Anticipated Refinement in Final Engineering for 2013 MS4 Permit, 2015 Model BMP Design Manual, and 2016 Local BMP Design Manual Electronic Files Compact Disc (CD): Electronic Files for Storm Water Management Model (SWMM) Map Pocket: Map Pocket 1: HMP Pre-Development Exhibit for Bressi Ranch (Bressi Ranch Lots 29 thru 32) Map Pocket 2: DMA/IMP Post-Project Exhibit for Bressi Ranch (Bressi Ranch Lots 29 thru 32) for Water Quality & HMP Prepared By: Rick Enginee1ing Company -Water Resources Division BH:SR:vs/Report/17169.006 11-24-14 Revised:3-25-15 Revised: 1-22-16 c_ J - J ._ _ _J .' __ j ,·-, L _I L __ J '_..I PRELIMINARY STORM WATER MANAGEMENT PLAN FOR BRESSI RANCH LOTS 29 THRU 32 (PRELIMINARY ENGINEERING) Job Number 17169 REVISION PAGE(S) January 22, 2016 This Storm Water Management Plan (SWMP) presents a revision to the March 25, 2015 report pursuant to the second plan check comments, minor modifications to the site layout, and to reflect some of the latest 'refined' criteria presented in the 2015 Model BMP Design Manual (June 2015). In particular, the Feasibility Worksheets for Infiltration and Harvest & Use have been included, which are required to demonstrate that use of Biofiltration BMPs are acceptable. This revision also includes checking the sizing criteria of the Bio filtration BMPs, as more defined criteria was released in the 2015 Model BMP Design Manual that was not included in the 2013 MS4 Permit itself. Additional design criteria is also under development for which the draft criteria was used, specifically related to the "Cistern to Biofiltration" concept that has been utilized_ for this project (i.e. -Underground Detention Vault dripping out to Biofiltration Planters). The use of permeable pavers with subdrains AND impermeable liners have also been addressed in this revision. When liners are used, they can no longer be counted as "pervious" areas. Furthermore even if liners are not used along the bottom, the subdrains would be required to be placed above the 35th percentile storm volume which is not feasible for this project location due to underlying soils. For this reason, the 'credit' previously reflected in the use of permeable pavers has been removed, though some locations of permeable pavers are still provided as site design BMPs (though modeled as impervious). Prepared By: Rick Engineering Company-Water Resources Division BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 L) \. ) r, LI . .J r_ i This revised report has added Appendices F, G, H, and I, which provides a summary of the refined criteria and identifies additional updates that will be incorporated during the final engineering stage of design and approval, following adoption and implementation of the City's Local BMP Design Manual after February 2016 (+/-). Please refer to the plan check copy of the SWMP for the plan check comments. All applicable updates have been reflected in this report, consistent with discussions w/ City staff on how best to implement the revised criteria while deferring further updates to final engineering permits and approvals. Prepared By: Rick Engineering Company-Water Resources Division BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 \ ... ) Li •. I (_ __ j r-· 1 1. J PRELIMINARY STORM WATER MANAGEMENT PLAN FOR BRESSI RANCH LOTS 29 THRU 32 (PRELIMINARY ENGINEERING) Job Number 17169 REVISION PAGE(S) March 25, 2015 This Storm Water Management Plan (SWMP) presents a revision to the November 24, 2014 report pursuant to the first plan check comments, minor modifications to the site layout, and removal of the round-about. The comments have been included below and the response-to- comments have been provided in italics. 3. A third party consultant will be reviewing the SWMP (with SWMM) and Geomorphic Assessment. An additional fee of $4,700 is required for said review. If the project is processed as a vesting tentative map, the SWMP shall be designed with the same amount of detail found in a final SWMP, which shall include a detailed design of the bioretention basin and storage vault, orifice sizing, volume calculations, flowline and invert elevations, etc. In addition, if the project does not receive discretionary approval prior to December, 2015, then delays in processing are likely as a redesign to the tentative map and revisions to the SWMP will be required to show compliance with the 2013 MS4 permit. Once the SWMP is revised to include the requested information above and the fee is paid, staff will forward for third party review. Please submit two copies of the revised SWMP and a check payable to the City of Carlsbad for $4,700 to David Rick's attention. Prepared By: Rick Engineering Company -Water Resources Division ii BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 \___) r-i ,_ j L_ i L--1 Response: The third party review and fee required is noted. This SWMP has been prepared in support of the discretionary permits; however, as reflected throughout this SWMP, detailed calculations have been provided for each of the proposed BMPs, including bioretention sizing, storage vault sizing, and outlet works pursuant to HMP criteria. A detailed analysis as well as outlet works has been provided in Appendix D and a summary of the results is provided in the report in Table 22. Small changes are expected to occur during final engineering related to horizontal or vertical alignment; however, it is expected they will be small in nature and remain consistent with the required volumes, sizes, and types of BMPs presented herein. Prepared By: Without knowing for sure whether the project would be subject to the 2013 MS4 Permit requirements or not (depending on Prior Lawful Approval), the project has been designed based on our current understanding of the 2013 MS4 permit which will be subsequently enforced through the BMP Design Manual which is anticipated for submittal to the Regional Board in June 2015 for review and approval, with an effective date of December 25, 2015 (+/-... subsequently pushed back to February 16, 2016 +/-). The design approach has been to provide water quality treatment using Bioretention (referred to as Biofiltration BMPs, with subdrains, in the 2013 MS4 Permit) since that will still be an acceptable TC-BMP for on-site compliance. The HMP volume is being detained in underground vaults and the outlet works are designed using continuous simulation to reduce the impacts to the downstream channels. The HMP modeling has been performed using 0% impervious, for the pre-development condition, which reflects the 2013 MS4 Permit requirements to use a "pre- development" condition for HMP purposes, rather than pre-project. Therefore, it is our understanding that the project as currently designed meets the intent of the 2013 MS4 Permit, including water quality treatment and hydromodification management. That said, the project is still anticipated to seek approvals in a timely manner and will prefer to remain 'technically' subject to the 2007 MS4 Permit; despite implementing these more progressive design measures. Rick Engineering Company-Water Resources Division ii BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,' ~1 '-~ i ' '": !_I \ ___ ) Information summarizing the above has been included within the report for reference, within the Introduction, as well as the results section for the TC-BMPs and HMP, for reference purposes. The revisions to the layout included eliminating the round-about at the main entrance of the site and slightly shifting the location of the buildings and retaining walls. Changes to this report that were a result of these changes include: Prepared By: Two (2) additional bioretention basins have been added behind the curb returns of the main entrance to capture and treat the on-site run-off generated from the entrance driveway area identified as DMA-4. (See Map Pocket 2: DMA/IMP Post-Project Exhibit) Off-site Modular Wetlands have been removed because off-site improvements are no longer proposed. POC-2 has been removed since the project no longer proposes a round-about with Gateway Road and drainage towards the existing storm drain system near El Fuerte Street will not be impacted as a result of the project. The drainage areas and calculations for DMA-1, DMA-2, & DMA-3 have not s changed since the previous submittal. Rick Engineering Company -Water Resources Division II BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ---·1 L. I ;__ / :_ f --\ ____ ) 1.0 INTRODUCTION This Storm Water Management Plan (SWMP) summarizes the post-construction storm water requirements for the Bressi Ranch (Lots 29 thru 32) project (herein referred to as "the project") in support of preliminary engineering. The proposed project encompasses a 17 .3 acre site and is located at the southwest comer of the intersection of Palomar Airport Road and El Fuerte Street; the intersection is located approximately 0.5 miles east of the intersection of Palomar Airport Road and El Camino Real. Gateway Road fronts the property along the south and Colt Place fronts the property along the west. See Figure 1, Vicinity Map, located at the end of Section 1.0. The project site was previously graded as part of the Bressi Ranch, Planning Area 4 project, under City of Carlsbad drawing number 400-8A, which was approved in December of 2003. The site has since remained undeveloped after completion of the mass grading operation. The existing terrain slopes at 2% to 2.5% from the northeast to the southwest. Subsequent grading and improvements were installed as part of drawing numbers: 400-8B, 400-8D, and 421-3. The preliminary analysis presented herein is in support of the entitlement phase of the project which includes processing a General Plan Amendment, Master Plan Amendment, and Site Development Permit to change the land use and zoning form Commercial/Industrial to Commercial/Industrial and Multi-Family Residential. For the purposes of post-construction storm water quality management, the project will follow the guidelines and requirements set forth in the City of Carlsbad's "Standard Urban Storm Water Management Plan (SUSMP)," adopted January 14, 2011 (herein "SUSMP"). Based on the City of Carlsbad Storm Water Standards Questionnaire, the project is a "Priority Development Project." The following Priority Development Project category applies to the project: "Housing subdivisions of IO or more dwelling units," Parking Lots," "Streets, roads, highways, and freeways," and "More than I-acre of disturbance." A copy of the City of Carlsbad Storm Water Standards Questionnaire for the project is located in Appendix A of this SWMP. Without knowing for sure whether the project would be subject to the 2013 MS4 Permit requirements or not ( depending on Prior Lawful Approval), the project was originally designed based on our current understanding of the 2013 MS4 permit, then subsequently updated based on additional design criteria identified in the Model BMP Design Manual which was finalized in June 2015 and submitted to the RWQCB for review and approval, pending adoption of the City's Local BMP Design Manual which is now anticipated to go into effect on February 16, 2016 (+/- ). That Prepared By: Rick Engineering Company -Water Resources Division BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 i __ / ~-_J ' l ( J ',_,_J Storm water runoff from the subject property is currently collected on-site and discharges at four (4) points of connection to an existing public storm drain system located within Gateway Road; the backbone system conveys runoff westerly within Gateway Road then southerly within Alicante Road ultimately discharging to an existing regional detention system. Constraints and opportunities for site design and selection of treatment and flow-control facilities have been identified for the project. The existing property is a mass graded site with D soils that does not lend itself to infiltration. The site design is comprised of two land uses; residential units that are of high density make up the west 7. 7 acres of the site and commercial/industrial which makes up the east 9.2 acres of the site. Constraints to locating vegetated drainage facilities include steep slopes along the perimeter of the subject property. Opportunities include utilizing non-contiguous sidewalks, landscaping within open space areas, and incorporating landscape/vegetated areas in proposed amenities such as dog runs. The landscaped areas provide opportunities for bioretention for treatment control or LID, or a cistern/vault could be located under a parking area or street with a bioretention area located directly downstream in a landscaped area. An integrated Low Impact Development (LID) approach will be utilized to provide a long-term solution to water quality at the project site. This SWMP is also intended to ensure the effectiveness of the BMPs or IMPs through proper maintenance that is based on long-term fiscal planning. Please refer to the DMA/IMP exhibit located in Map Pocket 1 of this report for locations of the drainage facilities and storm water LID/IMP facilities, including tributary drainage areas and flow patterns for the site. The Single-sheet BMP exhibit for the project will be provided as part of the final engineering. Prepared By: Rick Engineering Company -Water Resources Division 2 BH:SR:vs/Repmt/l 7169.006 l l-24-14 Revised: 3-25-15 Revised: 1-22-16 VICINITY MAP 'oMM{AtnPn f."'"' .. .. .. .. . . . <.ii?';- ~ L_J r~-1 VICINITY MAP Prepared By: Rick Engineering Company -Water Resources Division 3 INNOVA l!QN WY lO!(fR AVF W COll PL BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 !_~ ___ J (_~_j LJ \ __ I c __ l 2.0 IDENTIFICATION OF POLLUTANTS & CONDITIONS OF CONCERN Section 2 of the City of Carlsbad's SUSMP outlines the procedure for the selection of stormwater treatment facilities. The procedure begins with identification of pollutants with type of project/use, followed by identification of watershed and hydrologic unit basin number and receiving waters, list of impaired water bodies per the latest 303( d) List, and summary of primary pollutants of concern. 2.1 Identify Pollutants from the Project Area Table 2-1 of the SUSMP, "Anticipated and Potential Pollutants Generated by Land Use Type" identifies general pollutant categories that are either anticipated or potential pollutants for general project categories. The following general project categories listed in Table 2-1 apply to the project: "Attached Residential Development," "Parking Lots," "Restaurants," and "Streets, Highways & Freeways." These categories shall be used to describe the anticipated or potential pollutants for the project. Table 2-1 of the SUSMP is reproduced on the following page, with the Priority Development Project categories applicable to the project highlighted. Prepared By: Rick Engineering Company-Water Resources Division 4 BH:SR:vs/Repott/17169,.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 i __ J LI l_J L __ J Table 2-1. Anticipated and Potential Pollutants Generated by Land Use Type General Pollutant Cate ories Priority Project Categories Detached Residential Development Altachedi > -• ~~i,iclt;mtial:- , ri~velopnfent ,'-Commercial _p~v~top~~nt - -· >:100,00Q.cft i' Heavy Industry /Industrial Development Automotive Repair Shops Steep H11lside Development >5,000 ft2 . · Pa,rkingLotsC, Retail Gasoline Outlets _ Streets; -Highways& Freeways- X = anticipated P = potential Heavy Sediments Nutrients Metals X X X X X ( 1) A potential pollutant if landscaping exists on-site. Organic Compounds X x(4J<si (2) A potential pollutant if the project includes uncovered parking areas. (3) A potential pollutant if land use involves food or animal waste products. (4) Including petroleum hydrocarbons. (5) Includin solvents. Trash & Debris X X X Source: City of Carlsbad Standard Urban Storm Water Mitigation Plan, 2010. Oxygen Demanding Substances X X Bacteria Oil& & Grease Viruses Pesticides X X X X X Based on the highlighted rows, the anticipated pollutants from the project include sediments, nutrients, heavy metals, organic compounds, trash & debris, oil and grease, oxygen demanding substances and pesticides. Prepared By: Rick Engineering Company-Water Resources Division 5 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 i __ i l___J l,_J l __ _j L_j :_) 2.2 Identify Pollutants of Concern in Receiving Waters Based on Section 2 of the SUSMP, to identify pollutants of concern in receiving waters, the following analysis shall be conducted and reported in the project's SWMP: (1) for each of the proposed project discharge points, identify the receiving water(s), including hydrologic unit basin number( s ), as identified in the most recent version of the "Water Quality Control Plan for the San Diego Basin," prepared by the SDRWQCB; and (2) identify any receiving waters, into which the developed area would discharge to California's List of Polluted Waters [California's 200-2010 Section 303(d) List], a component of the California 2010 Integrated Report [Clean Water Act Section 303(d) List and 305(b) Report], approved by the USEPA on October 11, 2011. List any and all pollutants for which the receiving waters are impaired. Identification of Receiving Waters According to the "Water Quality Control Plan for the San Diego Basin," dated September 8, 1994, prepared by the SDRWQCB, the project is located in the following hydrologic unit basin: Batiquitos Subarea in the San Marcos Hydrologic Area within the Carlsbad Hydrologic Unit. The corresponding hydrologic unit basin number designation is 904.51 (Region '9', Hydrologic Unit '04', Hydrologic Area '5', and Hydrologic Subarea 'l '). An exhibit has been provided in Appendix B of this report titled, "Hydrologic Unit for Bressi Ranch (Lots 29 thru 32)" which shows the project location within Hydrologic Unit 904.51. Project runoff discharges to an existing storm drain system in Gateway Road, through a series of existing regional detention facilities, though the La Costa golf resort, into San Marcos Creek, and ultimately discharges into Batiquitos Lagoon. Prepared By: Rick Enginee1ing Company -Water Resources Division 6 BH:SR:vs/Report/17169.006 l l-24-14 Revised: 3-25-15 Revised: l-22-16 L_J [ __ J LJ i. J Identification of Receiving Water Impairments According to the 2010 303(d) List, several creeks within HU 904.51 are identified as an impaired water body. The San Marcos Creek is listed for pesticides (DDE), Nutrients (Phosphorous), Toxicity (Sediment Toxicity), and Metals (Selenium). Additional, impaired water bodies are located within HU 904.52; however, the remainder are located upstream of Batiquitos Lagoon and not a receiving water for this particular project. Pollutants of Concern for the Project Based on Table 2 and the 2010 CWA Section 303(d) List of Water Quality Limited Segments, the following are the project's pollutants of concern: sediments, nutrients, heavy metals, and pesticides. The Integrated Low Impact Development (LID) design approach, and source control BMPs will be utilized to treat these pollutants to the maximum extent practicable (MEP). Prepared By: Rick Engineering Company -Water Resources Division 7 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 I ___ ) l J L_J 3.0 SELECTION OF TREATMENT CONTROL BMPs Treatment control BMPs are designed to remove pollutants contained in storm water runoff. Methods of pollutant removal include sedimentation settling, filtration, plant uptake, ion exchange, adsorption, and bacterial decomposition. Pursuant to Section 4.4 of the Storm Water Standards, after source control BMPs and LID have been incorporated into the project, applicants of Priority Development Projects shall design a single or combination of treatment control BMPs designed to infiltrate, filter, and/or treat runoff from the project footprint. The required LID BMPs may be applied towards the numeric sizing treatment standards satisfactory to the City Engineer. In order to achieve compliance with the criteria in the SUSMP, the integrated Low Impact Development (LID) design approach has been selected for this project to size Integrated Management Practices (IMPs). The integrated LID design strategies are discussed in Section 6.0 of this report. Pursuant to Section 4.4.1, selection of treatment control BMPs shall be based on the following criteria, in conjunction with the performance ratings provided in Table 4-3: • For the anticipated project pollutants identified in section 4.1.5, the highest performing BMPs available shall be considered. Site constraints that limit the selection shall be described in the SWMP. • The most significant pollutants of concern for the project are those that both are ,-, anticipated, according to section 4.1.5, and are a concern for the receiving water, ,_1 according to section 4.1. 6. The minimum performance for the most significant pollutants of concern is "medium removal efficiency. " Priority Development Projects shall select a single or combination of treatment BMPs from the categories in Table 4-3 of the Storm Water Standards that maximize pollutant removal for the particular pollutants of concern. This means that the selected treatment control BMPs must Prepared By: Rick Engineering Company-Water Resources Division 8 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 L j . L __ J L_J l .J l_j collectively provide minimum pollutant removal efficiencies of "medium" or "high" for all pollutants of concern. Table 4-3 of the Storm Water Standards, "Structural Treatment Control BMP Selection Matrix," provides a guide for treatment control BMP selection. Table 4-3 is renamed as Table 3 .1 and reproduced below. The anticipated pollutants applicable to the project are highlighted. Table 3.1: Structural BMP Treatment Control Selection Matrix BMP LID Infiltration Basin y Biorete11~on, Basin ••·. .. ' ;' I;1,~?; Ci~t¢~~i~f~Jpreten~~il <' ·' •· ·~; ... , .. , .. ,.,, . Vault plus Bioretention y Self-retaining Area y Dry Wells y Constructed Wetlands y Extended Detention Basin y Vegetated Swale y Vegetated Buffer Strips y . ·.· . . Ji"• i .... · . ··v.· Flow-Tln'ough Planter B6xes <' :>· :. ·,'. ' ·. ,., . ,. 1; .. Vortex Seperator or Wet N Vault Media Filter N H High removal efficiency M Medium removal efficiency L Low removal efficiency HMP Sediment Nutrients Control y H H · .... ·y::l; If··· H\2;>\ ;ff{M .. 11, 1 • V:}f. }~.11,,' i:,%.,fvt,;,t,,.' y H M y H H y H H y H M N M L N M L N H L (' ... +•. ! • ff:%·( :. ; ''.it<, N M L N H L Trash Metals Bacteria Oils and Organics Grease H H H H H ... . ... ·,. '. ····1n·> {I;t. :;' ... H·' • t::L;;, Hi'" ... · . I :1,.;,Hr ;: :: . "1{,/ {, ;.;;< ;~:\, .. ... H: . . ·· •, . " ·:· >·• ,· H H H H H H H H H H H H H H H H H H H H H M M M M L M L M M M H L H M :; t:fi(' .. .. ,,.,> . .. ··itfY: ,. ,·:· .: I,; H .Jl. .. X . •.··. ·• ... i.'· . · .. M L L L L H H M H H The following discussion identifies the treatment control BMPs proposed for the project. As discussed in Section 2.0, the most significant pollutants of concern for the project are those that both are anticipated, and are a concern for the receiving water (as described by Section 4.4.1 of the Storm Water Standards). They are sediments, heavy metals, organic compounds, Prepared By: Rick Engineering Company -Water Resources Division 9 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ' ' L.__j :_j \,. __ ./ l _I I j , __ J ' --J L __ J pesticides, and bacteria & viruses. The Storm Water Standards states that the m1mmum performance for the most significant pollutants of concern is "medium removal efficiency." All of the BMPs listed in the Storm Water Standards -Table 4-3 were evaluated. It was determined that the most practicable and effective treatment BMPs will be: • Five (5) Bioretention Basins (on-site) Bioretention basins were selected primarily based on the following considerations: • The project mainly consists of Type D soils; therefore, infiltration is not feasible. • A bioretention basin will treat for sediments, trash & debris, heavy metals, bacteria & viruses, oil & grease, and organics at a high level of removal efficiency and treat for nutrients at a medium level of efficiency. • • A bioretention basin provides a higher level of treatment for several pollutants of concern in comparison to alternative treatment control BMPs. Nutrients will also be managed using source control BMPs, which can be more effective than treatment. 3.1 Numeric Sizing Requirements for Treatment Control BMPs For flow-based treatment control BMPs (Bioretention Basins and Flow through Planter Boxes), the treatment flow rates were calculated based on the following equation: • Rational method equation: Q = CIA, • 'Q' is the treatment flow rate in cubic feet per second (cfs), • 'C' is the weighted runoff factor, • 'I' is the rainfall intensity in inches per hour (in/hr) [0.2 in/hr per flow-based numeric sizing criteria], and • 'A' is the drainage area is acres (ac) . Prepared By: Rick Enginee1ing Company -Water Resources Division LO BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 , ___ I l ___ _l L _ __j L_J ', I 1 __ J c__J ,-, 3.2 Results for Treatment Control BMPs Five (5) bioretention basins will be provided to meet the water quality treatment requirements for the project, three (3) of which will rely on an upstream "Cistern" to collect, store, and slowly release the Water Quality Volume into the Bioretention BMP. The other (2) are small bioretention areas to treat the driveway entrance off of Gateway Road. The water quality treatment calculations are included in Appendix C of this report. Typical details of the selected Treatment Control BMPs are also included in Appendix C. The locations of all storm water management features are shown on the exhibit titled "DMA/IMP Exhibit for Bressi Ranch (Lots 29 Thru 32) (Post-Project for WQ & HMP," located in Map Pocket 2. Note regarding 2013 MS4 Permit and TC-BMP Design: The design approach has been to provide water quality treatment using Bioretention (referred to as Biofiltration BMPs, with subdrains, in the 2013 MS4 Permit) since that will still be an acceptable TC-BMP for on-site compliance. The HMP volume is being detained in underground vaults and the outlet works are designed using continuous simulation to reduce the impacts to the downstream channels. The HMP modeling has been performed using 0% impervious for the pre-development condition, which reflects the 2013 MS4 Permit requirements to use a "pre-development" condition for HMP purposes, rather than pre-project. Therefore, it is our understanding that the project as currently designed meets the intent of the 2013 MS4 Permit and 2015 Model BMP Design Manual, including water quality treatment and hydromodification management. The project anticipates making additional updates during the final engineering design and approval stage which will reflect further refinements in the 2016 Local BMP Design Manual which will go into effect around February 16, 2016 (+/-). A summary of additional information pertaining to the revised MS4 Permit criteria has also been provided in Appendix I. Prepared By: Rick Engineering Company -Water Resources Division ll BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 1--1 i _ _J LJ LJ L __ _J 4.0 HYDROMODIFICATION STUDY AND FINDINGS 4.1 Background The intent of this section is to meet requirements of Provision D. l .g of the California Regional Water Quality Control Board San Diego Region Order R9-2007-0001, which requires the San Diego Stormwater Copermittees to implement a Hydromodification Management Plan (HMP). Hydromodification refers to changes in a watershed's runoff characteristics resulting from development, together with associated morphological changes to channels receiving the runoff, such as changes in sediment transport characteristics and the hydraulic geometry (width, depth, and slope) of channels. These changes can result in stream bank erosion and sedimentation, leading to habitat degradation due to loss of overhead cover and loss of in-stream habitat structures. As required by Permit Order No. R9-2007-0001, each Copermittees was required to incorporate the approved Hydromodification Management Plan (HMP) into its local Standard Urban Storm Water Mitigation Plan (SUSMP) and implement the HMP for all applicable Priority Development Projects (PDP) by January 14, .ZOl l. The project is subject to the Final Hydromodification Management Criteria. Therefore, a hydromodification management strategy has been developed for the project based on the Final Hydromodification Management Plan (HMP), dated March 2011. A continuous simulation model, the Environmental Protection Agency (EPA) Storm Water Management Model (SWMM) version 5.0, was selected to size mitigation measures. The SWMM model is capable of modeling hydromodification management facilities to mitigate the effects of increased runoff from the post-project condition and land use changes that may cause negative impacts (i.e. erosion) to downstream channels. The storm water management features will also provide Priority Development Project LID benefits and water quality treatment. Three (3) underground detention facilities will be used to provide the required HMP volumes. HMP volume sizing was performed using the Storm Water Management Model (SWMM) (water quality treatment is sized separately). More details are discussed in Sections 4.2 and 4.3. Prepared By: Rick Engineering Company-Water Resources Division 12 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ' ___ J ,-, LJ 4.2 Hydromodification Management Criteria Based on the Final Hydromodification Management Plan, dated March 2011, a range of runoff flow rates was required to be determined to identify the range for which Priority Development Project (PDP) post-project runoff flows and durations shall not exceed pre-development runoff flows and durations. In order to meet these criteria, results of a hydromodification management analysis must meet the following criteria: • For flow rates between the pre-development lower flow threshold (10%, 30%, or 50%) of the pre-development 2-year runoff event (0.1 Q2, 0.3Q2, or 0.5Q2) to the pre-development 10-year event (Q 10), the post-project discharge rates and durations may not deviate above the pre- development rates and durations by more than 10% over more than 10% of the length of the flow duration curve. LJ • Lower flow thresholds may be determined using the HMP Decision Matrix along with a L_J ,---, L_.J ·c____J ~-j critical flow calculator and channel screening tools developed by the Southern California Coastal Water Research Project (SCCWRP). These methods identify lower flow thresholds for a range of channel conditions. The critical flow calculator recommends a lower flow value of 0.1 Q2, 0.3Q2, or 0.5Q2 dependent on the receiving channel material and dimensions. This value will be compared to the channel susceptibility rating (High, Medium, or Low) as determined from the SCCWRP screening tools to determine the final lower flow threshold. • The lower flow threshold may alternately be determined as 10 percent of the pre- development 2-year nmoff event, or 0.1 Q2: This approach, which is outlined in the HMP Decision Matrix, is available if the project applicant chooses not to complete the channel screening analysis. • For flow rates ranging from the lower flow threshold to Q5, the post-project peak flows shall not exceed pre-development peak flows. For flow rates from Q5 to Q,0, post-project peak flows may exceed pre-development flows by up to 10 percent for a I-year frequency interval. For example, post-project flows could exceed pre-development flows by up to 10 percent for the interval from Q9 to Q10 or from Q5_5 to Q6.s, but not from Qs to Q10. Prepared By: Rick Enginee1ing Company-Water Resources Division 13 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: l-22-16 L.I ;___J L. I LJ r--1 L) -1 The project has elected to perform the continuous simulation modeling using the lower flow threshold of 0.3Q2 for drainage to POC-1. In order to qualify for a low flow threshold other than 0.1 Q2 (i.e., 0.3Q2 or O.SQ2), a geomorphic assessment must be performed. A geomorphic assessment for drainage area to POC-1 was performed to show that the downstream channels have medium susceptibility to erosion (i.e., 0.3Q2). For additional information, refer to the report titled, "Geomorphic Assessment for Bressi Ranch (Lots 29 to 32)," dated November 24, 2014, prepared by Rick Engineering Company (Job Number 17169). 4.3 Model Development The Bressi Ranch project proposes the development of multi-family residential buildings, commercial buildings, and parking lots on a previously graded site, as well as street improvements along Gateway Road. Drainage from the project site discharges to one (1) existing storm drain systems along Gateway Road and to one (1) Point of Compliance (POC) locations labeled, POC-1. The post-project areas tributary to POC-1 are DMA-1, DMA-2, DMA-3 and DMA-4 which are modeled using SWMM to meet HMP criteria. The post project areas tributary to POC-1 can be seen on the DMNIMP exhibit for the HMP & Water Quality found in Map Pocket #2. For drainage to POC-1, a set of pre-and post-project SWMM models have been prepared. Overview The SWMM model is a rainfall-runoff hydrology model designed to model urban areas for both single storm and continuous events. Precipitation is applied across the subcatchments in the model and runoff is generated and routed at a user-specified analysis time step as appropriate based on model input (i.e., output analysis cannot be performed at a higher resolution than input data). SWMM is capable of modeling the temporal variability of precipitation, evaporation, interception storage, infiltration/percolation, interflow, reservoir routing, capture/retention LID devices, etc., and has a wide range of applications for storm water management. Meteorological Options Prepared By: Rick Engineering Company~ Water Resources Division 14 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 (,,_, L.) ,---1 LJ r-·-, L___LJ. ---1 L __ J L..J ;_j L_J '.,sJ Inputs required for the SWMM model include: meteorological data, watershed characteristics, soil characteristics, and BMP configuration. The SWMM model requires meteorological data inputs for historical rainfall and monthly average pan evaporation. It was determined that the Encinitas gauge was the most appropriate gauge for use in the SWMM model due to its proximity to the project site and the rainfall pattern (based on the 10-year, 6-hour isopluvial map in the 2003 County of San Diego Hydrology Manual). Hourly rainfall data for the Oceanside gauge was obtained from the Project Clean Water website for the period of record of 8/28/1951 to 5/23/2008. Based on analysis time steps suggested in the SWMM Applications Manual (July 2009), the following time steps were utilized: Reporting Time Step: 1 hour Runoff: Dry Weather: 4 hours 'Runoff: Wet Weather: 15 minutes Routing: 1 hour Long-term monthly average pan evaporation depths were obtained from the Western Regional Climate Center (WRCC) website for the Chula Vista gauge (period of record from 1948 to 2005). The project was modeled with Type D soils per the Natural Resources Conservation Service (NRCS) Web Soil Survey. Refer to Appendix E for a copy of the soil report. Infiltration Models The SWMM model includes three options for modeling infiltration including: Horton, Green- Ampt, and SCS Curve Number. The Horton model utilizes empirical parameters which are typically calibrated with field measurements to match single storm events, thereby making it less suitable for continuous simulation. The SCS Curve Number model was designed to simulate the hydrology of large watersheds (greater than one square mile) and flood control design storm events, thus it is not appropriate for use on small drainage basins and for low flow events. The Prepared By: Rick Engineering Company-Water Resources Division 15 BH:SR:vs/Repott/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,-, ,·" l-' L _ _J L_J ,J L __ i \,_,_J ,-·1 Green-Ampt infiltration model was selected as the most appropriate infiltration model because it is derived from Darcy's law and utilizes physically measured parameters making it more suitable for continuous simulation. Flow Routing Options There are three flow routing models within the SWMM model including: Steady Flow, Kinematic Wave, and Dynamic Wave. Steady Flow routing model was not selected because the model oversimplifies the hydrology within small drainage basins and assumes that the flow is uniform and steady over each computation time step, thereby outputting results too coarse for this analysis. Given that the time of concentration for small basins is much shorter that the hourly rainfall data, the Steady Flow routing model is not appropriate for modeling low flow events. The Dynamic Wave routing model requires a computation time step much smaller than the data available; thus, the Kinematic Wave model is a more appropriate routing method. Refer to Appendix E for an explanation of the parameters selected for hydromodification analysis. Model Post-Processing Peak Flow Exceedance The Storm Water Management Model (SWMM) has built-in statistical capabilities which can be used to determine the frequency of recurrence (return period) using a partial duration series. The partial duration series is the recommended by the Final HMP. SWMM uses the Weibull plotting method to determine return periods for each peak flow event. Peak flows are interpolated from the SWMM model between the lower flow threshold (0.3Q2) and QlO for use in comparing the pre-and post-project peak flow rates to meet the Hydromodification Management Criteria. Prepared By: Rick Engineering Company-Water Resources Division 16 BH:SR:vs/Report/17169,006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 LJ ~-__ ) L) 4.4 Drainage Characteristics and HMP Strategies Drainage characteristics for the project are discussed in Section 1.3 of this report and in the supporting drainage study, titled, "Drainage Study for Bressi Ranch (Lots 29 thru 32)," dated November 24, 2014 (and any revisions thereafter). An HMP analysis was performed on Basins 1 through 4 which outfall to POC-1. As previously mentioned, both a pre-and post-project SWMM model has been created for each drainage system to meet the Hydromodification Management Criteria. The development of the site will create more impervious surfaces that result in an increase in storm water runoff and potential urban pollutants, typically associated with developed land use. Therefore, the implementation and design of these hydromodification management BMPs will 1 comply with the requirements in the City of Carlsbad SUSMP, dated January 14, 2011. The following provides a description of the drainage characteristics and hydromodification l.~1 management strategy subject to the Final Hydr'omodification Management Criteria. "·· .J Pre-Development Condition :,. c1 In the pre-development condition, the project is comprised of open space I undeveloped area r~r (pervious), previously mass graded. The project lies on Type D soils and the average slope for L.J ,i___J the site is flat, approximately 2.5%. Refer the Map Pocket 1 for an exhibit of the pre- development condition. Post-Project Condition In the post-project condition, drainage will be conveyed through a network of storm water management features for Priority Development Project LID requirements, water quality treatment, and hydromodification management prior to discharging into underground detention vaults. The following is the breakdown of the post-project surface types and associated areas for each Basin. Prepared By: Rick Engineering Company-Water Resources Division 17 BH:SR:vs/Repott/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 \'_ j l.) , __ ) • I L_..J Basin 1 The total area for Basin 1 is 7.7 acres. Basin 1 contains the following post-project surface type and acreage breakdown: impervious (6.9 acres) and pervious (0.8 acres). Basin 2 The total area for Basin 2 is 7.9 acres. Basin 2 contains the following post-project surface type and acreage breakdown: impervious (5.5 acres) and pervious (2.4 acres). Basin 3 The total area for Basin 3 is 1.3 acres. Basin 3 contains the following post-project surface type and acreage breakdown: impervious (0.9 acres) and pervious (0.4 acres). Basin4A The total area for Basin 4A is 0.2 acres. Basin 4A contains the following post-project surface type and acreage breakdown: impervious (0.12 acres) and pervious (0.08 acres). Basin 4B The total area for Basin 4B is 0.2 acres. Basin 4B contains the following post-project surface type and acreage breakdown: impervious (0.12 acres) and pervious (0.08 acres). The design of Basins 1 through 3 includes an underground detention/HMP vault which outfalls to a bioretention basin for each of the three drainage areas. This vault will be utilized to provide both the required water quality volumes and the required HMP volumes. The maximum low flow rate out of the underground vault is restricted by the maximum percolation rate through the bioretention soil based on an assumed infiltration rate of 5 inches per hour. The storage volume above the required water quality volume does not requtre treatment; therefore, those flows are allowed to bypass the bioretention basin and connect directly to the downstream storm drain system on Gateway Road. Flows are controlled at the first cleanout downstream of the "overflow" storm drain through the use of a concrete baffle wall. For flows above the required volume, a secondary opening (mid flow orifice) with a flowline set at the Prepared By: Rick Engineering Company -Water Resources Division 18 BH:SR:vs/Repmi/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,-, .~, i_J i J J \_ __ J required water quality volume is proposed. Flows above the required HMP volume will weir flow over the baffle wall and out to the existing storm drain system on Gateway Road. The 100- year outlet elevations are set at the water quality volume elevation inside the basin. The outlets from Basins 4A/4B confluence with the outlet of the underground vault in Basin 2. Basins 4A & 4B are designed for water quality treatment only, as this small drainage area has been included in the HMP modeling as undetained 'bypass', such that the total combined flows still meet the HMP criteria at the point of compliance, POC-1. Refer to Appendix D for a schematic of the outlet works for the underground vault. Summary of Results and Storm Water Management Model (SWMM) Output The sizing for required HMP volumes is included in the SWMM results, located in Appendix E of this report. The SWMM model provides a calculation for the peak flow statistics and summarizes peak flows at each return period. Peak flow rates for key return periods between the lower flow threshold and the 10-year event were identified to demonstrate that the post-project peak flows are less than the pre-development peak flows, thereby complying with the Hydromodification Management Criteria for peak flow frequency. Refer to Appendix E for a summary of the peak flow rates and a plot of the peak flow frequency curves. For the flow duration analysis, the SWMM output runoff time-series were extracted to demonstrate that post-project flows within the lower flow threshold and the 10-year range were below the pre-development flows. The range of flows between the lower flow threshold and QlO was divided into 100 equal time intervals to quantify the flow frequency within each interval. If the post-project frequency exceeded the pre-development frequency by more than 10%, the interval would fail to meet the requirement. For up to 10% of the time, post-project frequencies are allowed to exceed the pre-development frequencies by up to 10%. Results from this analysis are summarized in Appendix E. Prepared By: Rick Engineering Company-Water Resources Division 19 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 I --, ,) i_ ) \_ i ) _J Based on the results, the required HMP volumes for Basin 1, Basin 2, and Basin 3 are 28,440 cubic feet (ft\ 25,517 cubic feet (ft\ and 3,806 ft3, respectively. Each underground detention facility (i.e. vault) will be designed to provide the required HMP volumes. The low flow orifices were sized manually to reflect the actual head provided, measured from the storage volume to the low flow orifice elevation and included in the SWMM model. Additionally, mid flow opening and overflow (flood control) outlets were also modeled in SWMM to accurately depict all three outlet locations in the flow frequency and flow duration statistics. A summary of the outlets is provided below in Table 3.3. Table 4-2: Summary of Hydromodification Management Plan (HMP) Results (via Storm Water Management Model (SWMM)) Required Pre-Low Mid Height Drawd- Project Pre-Pre-Post-HMP project Flow Flow of Mid down Basin Basin Rainfall Drainag project project% project% Volume Low-Orifice Orifice Flow Time ID Area Basin e Soil Slope Imp. 2 Imp. 2 v. flow, Size Size Orifice3 (hrs) (acres) (ft3) 0.3Q2 (in) (in) (ft) (cfs 1) Basin 1 7.7 Oceanside D Varies 0% 90% 28,440 2.3 12.5 2.4 55 Basin 2 7.9 Oceanside D Varies 0% 92% 25,517 1.8 13 2.6 72 0.254 20 Basin 3 1.3 Oceanside D Varies 0% 92% 3,806 1.3 4 2.1 Basin4 0.4 Oceanside D Varies 0% 60% NIA NIA NIA NIA NIA Note: 1. "cfs" = cubic feet per second 2. For pre-development and post-project weighted runoff coefficients and 50-year peak flow rates, refer to the report, titled "Drainage Study for Bressi Ranch (Lots 29 to 32)," dated November 24, 2014 (and any revisions thereafter), prepared by Rick Engineering Company (J-17169). Water quality treatment calculations (required treatment flow rates I surface area) are provided in Appendix C of this report. 3. This height represents the depth of the full water quality volume. The mid flow orifice is set above the full water quality volume to ensure that all runoff associated with the water quality volume outflows to the biofiltration basin. A compact disc (CD) is also provided at the end of this report that includes the electronic files (i.e., SWMM input files, rainfall data). Drawdown calculations are provided in Appendix F. Details regarding water quality calculations and depiction of each storm water management design BMPs were discussed in Section 3 .1, 3 .2 and 3 .3 of this report. Prepared By: Rick Engineering Company -Water Resources Division 20 BH:SR:vs/Repott/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 {_ ) I .J 't.... J I " ·-.....,,J ',-J I j ~. I 4.5 Conclusion -HMP Analyses In addition to complying with the water quality requirements, the HMP analyses using Storm Water Management Model (SWMM) (version 5.0) has been prepared for the Bressi Ranch project to size a total of three (3) underground facilities as the hydromodification management BMPs (i.e. flow control) for Basins 1 through 3. The results demonstrate that the post-project peak flows and durations do not exceed the pre-development peak flows and durations, thus complying with the Final Hydromodification Management Criteria. Note regarding 2013 MS4 Permit and HMP Design: The design approach has been to provide water quality treatment using Bioretention (referred to as Biofiltration BMPs, with subdrains, in the 2013 MS4 Permit) since that will still be an acceptable TC-BMP for on-site compliance. The HMP volume is being detained in underground vaults and the outlet works are designed using continuous simulation to reduce the impacts to the downstream channels. The HMP modeling has been performed using 0% impervious for the pre-development condition, which reflects the 2013 MS4 Permit requirements to use a "pre-development" condition for HMP purposes, rather than pre-project. Therefore, it is our understanding that the project as currently designed meets the intent of the 2013 MS4 Permit, including water quality treatment and hydromodification management. That said, the project is still anticipated to seek approvals in a timely manner and will prefer to remain 'technically' subject to the 2007 MS4 Permit; despite implementing these more progressive design measures. Prepared By: Rick Engineering Company-Water Resources Division 21 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,-i L) 1--1 \.__) ~--/ 5.0 DRAINAGE STUDY The project site in the post-project condition has been divided into four (4) separate drainage basins: Basin 100, Basin 200, Basin 300, and Basin 400. • In general, Basin 100 storm water runoff is conveyed overland toward Colt Place (Outfall #2) prior to entering the existing storm drain line within Colt Place. • Basin 200 storm water runoff is conveyed overland and is collected and conveyed via on-site storm drain facilities toward Gateway Road (Outfall #4) and enters the existing backbone storm drain within Gateway Road. • Basin 300 storm water runoff is conveyed overland and is also collected and conveyed via on-site storm drain facilities toward Gateway Road (Outfall #3) prior to entering the existing storm drain line within Gateway Road. • Basins 4A/4B storm water runoff is conveyed overland and is collected and conveyed via a reverse D25 inlet structure and directed toward a biorentention basin before outleting into Gateway Road (Outfall #4) and enters the existing bapkbone storm drain within Gateway Road. The project site's runoff is less than the 100-year design flows assumed for the ultimate condition for the site when the previous mass grading phase was complete and public storm drain infrastructure was installed. The decrease in peak discharge is attributed to the land use change from Commercial/Industrial to Multi-Family Residential coupled with an increased time of concentration due to on-site routing. Pursuant to the Storm Water Management Plan (SWMP) Requirements Checklist, a drainage study is not required to compare pre-and post-development runoff rates since the project incorporates the integrated LID approach to meet the criteria in the SUSMP. However, a drainage study was prepared to compute storm water runoff from the project area and preliminarily size proposed storm drains. A drainage study, titled "Drainage Study for Bressi Ranch (Lots 29 thru 32)," dated March 25, 2015, or any revision thereafter (prepared by Rick Engineering Company, Job No. 17169), presents hydrologic and hydraulic analyses for the project. Prepared By: Rick Engineering Company-Water Resources Division 22 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 '· I ,,---i 6.0 INTEGRATED LOW IMPACT DEVELOPMENT (LID) DESIGN STRATEGIES The following discussion addresses requirements of Section 4 of the SUS MP. As listed in the section, projects subject to Priority Development Project requirements, at minimum, must implement an integrated low impact development (LID) approach to develop and size Integrated Management Practices (IMPs) or "Alternatives to LID Design," which requires you to show how you satisfy each stormwater objective separately. The project will implement an integrated LID approach to meet criteria described in the SUSMP. As an approach to Integrated LID design, the following sections will discuss LID strategies for managing runoff from the project. 6.1 Optimization of Site Layout The project is located on the previously mass-graded lot and there are no creeks, wetlands and riparian habitats that the project needs to be set back from. Therefore, the project is not disturbing natural areas. Wherever feasible, landscape and vegetated areas will be utilized to minimize directly connected impervious areas. In order to maximize canopy interception and water conservation, the project will provide native or drought tolerant vegetation for proposed landscape areas and include trees for canopy interception. 6.2 Use of Pervious Surfaces Pervious surfaces such as porous pavement and permeable pavers have been incorporated into the commercial portion of the site.. The inclusion of additional pervious areas within the residential areas will be evaluated and implemented during final engineering. This option is open at this time and is viewed as a viable method for TC-BMP/IMP or Hydromodification Management (HM) within the voids of the sub-surface gravel. Prepared By: Rick Engineering Company-Water Resources Division 23 BH:SR:vs/Report/17169.006 l l-24-14 Revised: 3-25-15 Revised: 1-22-16 \ __ i \ .. _) /....._) \ .. _j L __ j --) c __ J \ __ J 6.3 Dispersal of Runoff to Pervious Areas Where feasible, the project site incorporates landscaping areas on the site that collect runoff from impervious surfaces prior to collection into the storm drain system. Portions of roof top runoff will be discharged to the adjacent landscaping area before getting into the storm drain system. Also, the sidewalk is designed as non-contiguous, thereby allowing sidewalk runoff to flow across the vegetated parkway prior to conveyance within the street, except locations where the sidewalk is adjacent to parking stalls. In cases where runoff is not feasibly diverted to landscaping, the approach will be taken to direct runoff towards pervious areas such as pervious pavers. It is also important to note; the majority of on-site runoff will be conveyed through bioretention basins and therefore it will not be directly connected to the off-site storm drain system. 6.4 Use of Integrated Management Practices The term "Integrated Management Practice" (IMP) refers to a facility that provides small-scale· treatment, retention, and/or detention and is integrated into site layout, landscaping and drainage design. Following tables of the City SUSMP have been evaluated to determine appropriate IMPs for treatment of runoff potentially containing most pollutants of concern. The tables are renamed as Table 6-1 and 6-2 and reproduced below. Table 6-1. Grouping of Potential Pollutants of Concern by Fate during Stormwater Treatment ----Infiltration Pollutants of Bioretention: Settling Wet Ponds Facilities or Media Concern Facilities•, Basins and Wetlands Practices Filters >-~lllDJ ---(Dry Ponds) / (LID) Coarse Sediment --- and Trash B;igll ---High High High High ''·" '\ ,~: Pollutants that tend to associate ftiglt) High High High High with fine particles during treatment --- Pollutants that tend to be _---- dissolved Medium •-Low Medium High Low following treatment -: - Source: City of Carlsbad Standard Urban Storm Water Mitigation Plan, 2011. Prepared By: Rick Engineeting Company -Water Resources Division 24 Trash Racks High-rate High-rate & Hydro-media biofilters filters dynamic Devices High High High Medium Medium Low Low Low Low BH:SR:vs/Report/l 7169.006 l 1-24-[4 Revised: 3-25-15 Revised: 1-22-16 ,_ I i,_ j I:_) :_) L J' \..., ___ y '1 J Table 6-2. Groups of Pollutants and Relative Effectiveness of Treatment Facilities Pollutant Coarse Sediment and Pollutants that tend to Pollutants that tend to be associate with fine particles dissolved following Trash during treatment treatment Sediment X X Nutrients X X Heavy Metals X Organic Compounds X Trash & Debris X Oxygen Demanding X Bacteria X Oil & Grease X Pesticides X Source: City of Carlsbad Standard Urban Storm Water Mitigation Plan, 2011. Following Integrated Management Practices (IMPs) are considered appropriate for treatment of runoff potentially containing most pollutants of concern and listed in Section 4 of the SUS MP: • Bioretention facilities, which can be configured as swales, free-form areas, or planters to integrate with your landscape design -Selected (adjacent to driveway entrance from Gateway Road) • Flow-through planters, which can be used near building foundations and other locations where infiltration to native soils is not desired-Not Selected • Dry wells, which can be used only where soils are permeable -Not Selected • Cisterns, in combination with a bioretention facility-SELECTED (for on-site) Prepared By: Rick Engineering Company-Water Resources Division 25 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 \ _) L.J ( __ / ,:,, J -.I In order to determine the most appropriate IMP ( or combination thereof) for the project, several design alternatives were considered. The site is composed of high density condominium units. The site is currently mass graded and has D type soils so it is unlikely that infiltration is occurring. The cistern to bioretention was determined to be the best option. The underground vault will be sized for HM and WQ volume. An adjacent landscaped area will be utilized as bioretention to treat the water quality storm event over approximately 24-hours of drawdown from the vault. Pursuant to the above descriptions of each category of IMPs, along with the constraints and opportunities that were evaluated with the project design, cistern with bioretention facility is the most suitable IMP for the project. Prepared By: Rick Engineering Company-Water Resources Division 26 BH:SR:vs/Repoti/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ~-j 1--J c. I i ! !r'l \ ___ j CJ l. J 7.0 DOCUMENTATION OF DRAINAGE DESIGN As stated in Section 4 of the SUSMP, the design documentation procedures begin with delineation of Drainage Management Areas (DMAs) prior to sizing each Integrated Management Practice (IMP). A brief description of the cistern with bioretention facility sizing is discussed below. For additional documentation of Drainage Management Areas (DMAs) and Integrated Management Practices (IMPs ), please refer to the IMP sizing calculations in Appendix C and DMA/IMP exhibit in Map Pocket 2 of this report. Cistern with Bioretention Facility • The cistern includes an orifice design at the outlet to restrict flow to provide a 24-hour drawdown time for the water quality volume and 96 hours for the HM volume. • The orifice opening is to be determined based on a more specific analysis of the project site. • The minimum area of the bioretention facility is provided to treat the maximum discharge • • rate from the orifice based on a percolation rate of 5" per hour through the engineered soil. The outlet pipe from the cistern to the bioretention facility is to be determined and will be equal to or greater than the minimum 2" requirement based on page 104 of the City SUSMP. The bioretention portion of the facility includes a perforated PVC underdrain and an atrium drain or catch basin will be sized to adequately convey the maximum discharge rate entering the bioretention area. • Since an orifice opening can be prone to clogging due to debris, several design features may be included: pre-treatment device upstream of cistern facility to help collect trash and debris two (2) access points at the inlet and outlet locations of the cistern a bypass system that ensures low-flows are conveyed to the cistern with bioretention facility; however, allows overflow and larger storm events to bypass directly to the downstream storm drain system. Note: For runoff associated with the driveway entrance from Gateway Road, standard biofiltrntion BMPs have been incorporated and sized for the water quality volume. Prepared By: Rick Engineering Company-Water Resources Division 27 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,_ ) 8.0 SOURCE CONTROL BMPs The term "source control BMP" refers to land use or site planning practices, or strnctures that aim to prevent urban rnnoff pollution by reducing the potential for contamination at the source of pollution. Source control BMPs minimize the contact between pollutants and urban rnnoff. The following discussion identifies the source control BMPs for the project. Table 8-1. Permanent and Operational Source Control Measures Potential source of Permanent source control BMPs runoff pollutants On-site storm drain • Mark all inlets with the words "No inlets Dumping! Flows to Bay" or similar (i.e. Lagoon/Ocean) Landscape I Outdoor • Design landscaping to minimize Pesticide Use irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides. • Consider using pest-resistant plants . • To insure successful establishment, select plants appropriate to site soils, slopes, climate, sun, wind, rain, land use, air movement, ecological consistency, and plant interactions. Loading Docks • Show a preliminary design for the loading dock area, including roofing 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 with a spill control valve or equivalent device, which shall be kept closed during periods of operation. Prepared By: Rick Engineeting Company -Water Resources Division 28 • • • • • • • • Operation source control BMPs Maintain and periodically repaint or replace inlet markings. Provide stormwater pollution prevention information to new site owners, lessees, or operators. See applicable operation BMPs in Fact Sheet SC-44, "Drainage System Maintenance in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Maintain landscaping using minimum or no pesticides. See applicable operation BMPs in Fact Sheet SC-41, "Building and Grounds Maintenance," in the CASQA Stormwater Quality Handbooks at www.cabmphandbooks.com Provide 1PM information to new owners, lessees and operators. 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 BH:SR:vs/Report/17169.006 . 11-24-14 Revised: 3-25-15 Revised: 1-22-16 • Provide a roof overhang over the loading area or install door skirts L __ ) ( cowling) at each bay that enclose the end of the trailer. Plazas, sidewalks, and • parking lots. ,_ J ' / \ ) / __ ) i. j Prepared By: Rick Engineering Company-Water Resources Division 29 • 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 collected and discharged to the sanitary sewer and not discharged to a storm drain. BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 l. j l __ J l. J 9.0 OPERATION AND MAINTENANCE The owner will ensure the ongoing maintenance for the permanent stormwater facilities proposed for the project. The owner will be responsible for properly disposing of waste material from their assumed areas within the project site, maintaining landscaping throughout those areas in a manner that will prevent soil erosion and minimize sediment transport, and maintaining drainage facilities located throughout the project area in a clean manner and in good repair. In addition, the owner will be responsible for maintaining all stormwater facilities Typical Maintenance Procedures for Stormwater Facilities The following stormwater facilities require permanent maintenance: underground cistern/vault facility, and bioretention facility. The discussions below provide inspection criteria, maintenance indicators, and maintenance activities for the stormwater facilities. Underground Cistern/Vault Facility (i.e. Manufacturer TBD) The underground vault facility will require maintenance. The underground vault system should require inspection, general maintenance and cleaning so it can remain free of litter, debris and sediment. The following are typical maintenance activities for underground vault facility: • Remove accumulated sediment, trash and debris from the vault. The vault can be accessed using two access points: at the inflow and outflow locations. Remove any accumulated material obstructing inlet or outlet facilities. • Inspect inlet and outlet facilities and/or other internal parts as applicable for structural integrity, and repair or replace if necessary. This includes the restrictor plate located in the downstream cleanout structure of the detention system. • For manufactured modular detention products, adhere to the manufacturer's specifications for maintenance procedures. Prepared By: Rick Engineering Company-Water Resources Division 30 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 --·---1 l J ~ _ __J ,-·1 Refer to manufach1rer, once determined, for more information on maintenance activities. Bioretention Facility • Inspect bioretention areas at least twice annually for erosion, damage to vegetation, and sediment and debris accumulation, preferably at the start and end of the wet season to be sure the area is ready for winter and to schedule follow-up maintenance, if necessary. Inspection should also occur after periods of heavy runoff to ensure continued functionality of each system (i.e. -0.5 inch storm events or greater). • Grass height and mowing frequency (if appropriate) may not have a large impact on pollutant removal. Consequently, mowing may only be necessary once or twice a year for safety or aesthetics or to suppress weeds and woody vegetation. • • Trash tends to accumulate in bioretention areas. The need for litter removal is determined through periodic inspection, but litter should always be removed prior to mowing. Sediment accumulating in bioretention areas should be removed when it builds up to 75 mm (3 in.) at any spot, or covers vegetation. • Regularly inspect bioretention areas for pools of standing water. Bioretention areas can become a nuisance and promote mosquito breeding in standing water if obstructions develop ( e.g. debris accumulation, invasive vegetation) and/or if proper drainage is not implemented and maintained. • Outfall locations that enter or exit facilities should be checked for eros10n, ponding, trash/debris, and other structural damage Permeable Pavers During inspection, the inspector shall check for the maintenance indicators given below: • Accumulation of sediment and debris • Loss of fill material between the pavers • Damaged or broken pavers • Standing water in the storage and draining layer indicating clogging in the underdrains Prepared By: Rick Engineering Company-Water Resources Division 31 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 I_ ) L J The surface of the pavers should be kept clean and free of debris. It will be necessary to carry out vacuuming and washing of the surface in order to keep the voids clear and allow them to function as they are intended. Street sweepers and vacuums can be used to maintain these types of pavers, and should be performed approximately 4 times a year. The level of fill material in the voids of the pavers should be checked and refilled when necessary, particularly after pressure cleaning. After installation, inspection should occur once a month for 4-6 months. After this time period inspection should occur annually, particularly after there has been heavy rain or storms, at which time the drainage voids can become clogged with organic debris. Sweeping and vacuuming the permeable surface should occur every 3 months. Landscaped Areas Inspection and maintenance of the vegetated areas may be performed by the landscape maintenance contractor. During inspection, the inspector shall check for the maintenance indicators given below: • Erosion in the form of rills or gullies • Ponding water • Bare areas or less than 70% vegetation cover • Animal burrows, holes, or mounds • Trash Routine maintenance of vegetated areas shall include mowing and trimming vegetation, and removal and proper disposal of trash. If erosion, ponding water, bare areas, poor vegetation establishment, or disturbance by animals are identified during the inspection, additional (non- routine) maintenance will be required to correct the problem. For ponding water or erosion, see also inspection and maintenance measures for irrigation systems. In the event that any non- routine maintenance issues are persistently encountered such as poor vegetation establishment, Prepared By: Rick Enginee1ing Company-Water Resources Division 32 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 LJ l.J ,. ·1 erosion in the form of rills or gullies, or ponding water, the party responsible to ensure that maintenance is performed in perpetuity shall consult a licensed landscape architect or engineer as applicable. As applicable, IPM procedures must be incorporated in any corrective measures that are implemented in response to damage by pests. This may include using physical barriers to keep pests out of landscaping; physical pest elimination techniques, such as, weeding, squashing, trapping, washing, or pruning out pests; relying on natural enemies to eat pests; or proper use of pesticides as a last line of defense. More information can be obtained at the UC Davis website (http://www.ipm.ucdavis.edu/WATER/U/index.html). Concrete Stamping Inspection/maintenance of the concrete stamping may be performed by the building/facilities maintenance contractor or other employees of the project owner, as applicable. In addition, there may be storm drain maintenance contractors who will perform this service for a fee. During inspection, the inspector(s) shall check for the maintenance indicators given below: • Faded, vandalized, or otherwise unreadable concrete stamping There are no routine maintenance activities for the concrete stamping. If inspection indicates the concrete stamping is intact, no action is required. If inspection indicates the concrete stamping is not legible, the concrete stamping shall be repaired or replaced as applicable. Prepared By: Rick Engineering Company -Water Resources Division 33 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 CJ i~) l_ _/ -I Irrigation Systems Inspection and maintenance of the irrigation system may be performed by the landscape maintenance contractor. During inspection, the inspector shall check for the maintenance indicators given below: • Eroded areas due to concentrated flow • Ponding water • Refer to proprietary product information for the irrigation system for other maintenance indicators, as applicable Refer to proprietary product information for the irrigation system for routine maintenance activities for the irrigation system, as applicable. If none of the maintenance indicators listed above are identified during inspection of the irrigation system, no other action is required. If any of the maintenance indicators listed above are identified during the inspection, additional (non-routine) maintenance will be required to restore the irrigation system to an operable condition. If inspection indicates breaks or leaks in the irrigation lines or individual sprinkler heads, the affected portion of the irrigation system shall be repaired. If inspection indicates eroded areas due to concentrated flow from the irrigation system, the eroded areas shall be repaired and the irrigation system shall be adjusted or repaired as applicable to prevent further erosion. If inspection indicates ponding water resulting from the irrigation system, the irrigation system operator shall identify the cause of the ponded water and adjust or repair the irrigation system as applicable to prevent ponding water. Refer to proprietary product information for the irrigation system for other non-routine maintenance activities as applicable. Inspection and Maintenance Frequency Typically, maintenance requirements are site and product specific, and will depend on the particular land use activities and the amount of gross pollutants and sediment generated within Prepared By: Rick Enginee1ing Company-Water Resources Division 34 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ',c.__j : __ J ! __ I ,'-\ \. _/ the drainage areas. If it is determined during the regularly scheduled inspection and routine maintenance that the BMPs/IMPs require more frequent maintenance to remove accumulated sediment, trash or debris, it may be necessary to increase the frequency of inspection and routine maintenance. The Table below lists the stormwater facilities to be inspected and maintained and the minimum frequency of inspection and maintenance activities. Table 9-1. Summary Table of Inspection and Maintenance Frequency (Minimum) BMP/IMP Inspection Maintenance Frequency Frequency Underground cistern/vault Twice a year, Routine maintenance to remove accumulated materials such as trash and debris: twice a year, on or before September 301h Facility (i.e. Manufacturer and after major As-needed maintenance based on maintenance indicators in this TBD) storm events section Twice a year, Routine maintenance to remove accumulated materials such as trash Bioretention Facility and after major and debris: twice a year, on or before September 30th As-needed storm events maintenance based on maintenance indicators in this section Permeable Pavers Annual As-needed based on maintenance indicators in this section · Routine mowing and trimming and trash removal: monthly Landscaped Areas Monthly Non-routine maintenance as-needed based on maintenance indicators in this section Concrete Stamping Annual As-needed based on maintenance indicators in this section Irrigation Systems Monthly As-needed based on maintenance indicators in this section Qualifications of Maintenance Personnel The LID and treatment control BMPs or IMPs are features that are integrated into site layout, landscaping and drainage design. The typical maintenance activities for landscaped areas and bioretention facility can generally be accomplished by typical landscape maintenance personnel. However, maintenance of the pre-treatment device (if applicable) and underground detention facility (i.e. Manufacturer TBD) may involve handing of potentially hazardous material; therefore, the maintenance operator must be trained in handling and disposing of hazardous waste. The contracting of additional services may be necessary if non-routine cleaning, disposal or repair is required for any of the project's stormwater facilities. Prepared By: Rick Engineering Company-Water Resources Division 35 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 , __ ) \.._.J , ___ I '--I If evidence of illegal dumping of hazardous materials is identified in a storm water facility, the illegally dumped materials shall be cleaned up and property disposed of. Specialized clean up and disposal of illegally dumped hazardous materials may be outside of the owner expertise. In this event, the owner shall contract for additional cleaning and disposal services as necessary if non-routine cleaning and disposal is required. Record Keeping Requirements The owner is responsible to ensure implementation and funding of maintenance of permanent BMPs and shall maintain records documenting the inspection and maintenance activities. Parties responsible for the operation and maintenance shall retain records for at least 5 years. Prepared By: Rick Engineering Company -Water Resources Division 36 BH:SR:vs/Report/17169.006 11-24-14 Revised: 3-25-15 Revised: 1-22-16 ,--, LJ '_J c l 10.0 SWMP CERTIFICATION STATEMENTS Preparer's Certification The selection, sizing, and preliminary design of stormwater treatment and other control measures _,/ in this plan meet the requirements of Regional Water Quality Control Board Order R9-_3907-JI/ 0001 and subsequent amendments. ( c1 s cf:-" 1 / 2 ~s /i '7 ) · Zc)i!> Brendan Hastie 1 Date R.C.E #65809, Exp. 09/17 Owner's Certification I certify that, as owner of the property described herein, I have read and understand the requirements of this Storm Water Management Plan (SWMP) and that I am responsible for ensuring that all storm water treatment measures described within said SWMP will be properly implemented, monitored and maintained. Sarah Morrell (Owner) Shea Homes 9900 Mesa Rim Road San Diego, California 92121 Kevin McCook (Owner) Shea Business Properties 9900 Mesa Rim Road San Diego, California 92121 Prepared By: Rick Engineering Company -Water Resources Division 37 Date Date BH:SR:vs/Report/17169.006 ll-24-14 Revised: 3-25-15 Revised: 1-22-16 APPENDIX A City of Carlsbad Storm Water Standards Questionnaire \_ ___ ! l _ __J '~} I_J ' ' L_ __ _j L .J l ___ J l _J STORM WATER STANDARDS QUESTIONNAIRE lai1cl Development: engineering 1635 Avenue 760-602<2750 lilat new d®v®!opmeot ood M,,,...,_,...,..,,,"''"t D,r:.r:ti""'" in!o the project 1::.n1Ji11s~rl11g Slandarrls Initially this rmJst be by the applicant lo adva!'lce of for a development app!lce!ioo rliscrelionary permits and!or construction permils). The resulls of lhe questionnaire determine !he !eve! of storm walet that must be appl!ed to a or redevelopment project. IJepam:l!ng on the outcome, your project win either be subject to 'Stam:lmrd Stormwater or be subject to m:idHkmal criteria called 'Priority Development Project Requirements', Many of site upon the storm water staw:lards applied to a project r"'""'"n"'''"' to ti1re quesliormaira represent an initial assessment of the proposed project oom:!iUorn, and r,rw,i::,hmru for the final m,rnessment after submisskm of the application. If s!aff dettirmines the '""'~r~"''"'lv f!!!ed out and is subject to more storm water than lnliially assessed you, this wm !he-return 001m!c,pm,,mt application as incomplete. In make the changes to the and resubmit to the City. !f you are unsure about the "'"''~"""' or mmd help in .-l<>lf"'"'"'"'"" how lo seek assistance from Land omm1c1omar1t Fn,r1,,.,,,,,.,,.,,, staff. "'"""'li,nn,n,;,i,,*' must be submitted for each new dat1aln,nment am,!icaticm v,;nen multiple development aoi:;Ecatk,ns e!so sign and submit a 1 NO the criteria: and ci:mstrucled to direct storm water runoff lo adjacent vegelated areas, or other non,erod!bte permeable a.teas; OR {2} and constructed to be hydraulical!y tilsconnacted from paved streets or roads; OR and oonstrucled wilh pavemenls or surfaces in to one or more of the above questions, !111,m your rl?.11!'!lrmm1an1 project and !oorefore is subject to storm water criteria ror last box "my does not me'ilt POP and COl'l'l!:tilet® 1:}f;jj:)il(:ant irtf.nm,,.t!!nn 1 of3 l. _J 'c_J ' J , __ J lsbad, QUESTION e .. 34 STEP2 ro 13! COMPli'fi[) FOR All Nl!!W OR R!OiVElOPMiNT PROJECTS feet or mom of imti@n.11ou:s supports a restaurant? rastaurtmt is a facifity sta,linnanr lunch counters and refreshment stands that creates 5,000 squme feet or more of impervious surface X co!iecitivelv over the entire site supports a hillside development project? A hiflside development "'"'""''" development on any n&tural !hat is twanty-five percent or grru!lter. X X o one or more of !he above questions, you ARE a priority c1e,1e!c,om>!rtt Best Pra<:tices (BMP's) in addition lo implementing Stenn Water f{eqwifements such low SMP's. A Storm Water Management Pian {SWMP) must be submitted wilh your for development. Go to still!) J for redevelopment projects, ror new projects, to step 4 at the end of this ~. check the "my project meets PDP requirements" box and appllcant lnf1:m1iatlon. Page 2 of3 am:l are therefore subject to de\re!ooment SMP's required for all ,-, u f'l I~ l __ J '1.-.. __ J L___i City rlsbad STORM WATER STANDARDS QUESTIONNAIRE E .. 34 If you answered •yes; the structural BMP's rl'ln.,;r.,rl surface and nol the en!lre de,,e!o,omenL corl'lr>li'lw ap;iilc;ant information. If you answered ·no; the structural BMP's for check the "m rcy ect meet% PDP m uiremanm" box m,H!IS PRIORnY OEWI..OPMEfff PROJECT per the SUSMP am::! ! und1;.rsland I must l urn:lerslam:! !low control (hydromodificalion) u1t,1m@•n!m project does not mH't POP rm1uirr1mr,nll! SUSMP. As part of these rnnn!rimsm,nt"' • E:nvironmen!al!y Sensitive Areas include but are not limited to an Clean Water Act Section water tmdies; arli!as designated as Areas of Biological by tM Resources Control Quality Control Plan for the San Diego Basin (1994) and amem:iments); water bodies wlth me RARE btaneficial use by Iha State Water Resources Control Board (Waler Quality Control Plan for the San Diego (1994) ancl amem:imenls); areas designated as preseruas or !heir under Iha Multi Spades Conseruation Program within IM Cities and of San Diego; and any ome, "'"""""''"'' errvlronmen!al!y sensitive areas which have been iden!ifled by the co:oermit:teais. 3of 3 ,,--1 L_J cl u '' , I r--1 l_J L ... J l~J ,-1 r-,, ;_ __ j E'!(c.,~fl -~1)fif\ 8-c \S 1,1\,cle \ J3Mf ]l-) '~Y\ tJ\0t,\1,ci1.:t \ Appendix I: Forms and Checklists Project Information [)rojectName:BRESSI RANCH (LOTS 29 THRU 32) Penni.t Application Nrnnber: Project Type Determination: Standard Project or PDP The project is (select one): [J New Development: i] Redevelopment The total proposed newly created or replaced impervious area is: 6t/~10Jt, ft2 ( ) acres Is the project in any of the f:dlowing categories, (a) through (Q? Yes No (a) Ne\v development projects that create 10,000 square feet or more of impervious surfaces 5;t i] Yes No ~ [] Yes No Pt !. .. n (b) (c) (collectively over the entire project site). 'fhis includes commercial, industrial, residential, mixed-use, and public development projects on public or private land. Redevelopment projects that create and/ or replace 5,000 square feet or more of impervious surface (colleclivcly over the entire project site on an existing site of 10,000 square feet or more of impervious surfaces). 'This includes commercial, industri:1l, residential, mLxed-use, and public development projects on public or private land. New and redevelopment projects that create 5,000 square feet or more of imper,.rious surface (collectively over tbe entire project site), and support one or more of the follo\v1ng uses: (i) Restaurants. This category is defined as a facility that sells prepared foods and drinks for consumption, including st;1tionary lunch counters and refreshment stands selling prepared foods and drinks foi: immediate consumption SIC code 5812). (ii) llillsidc development projects. This category includes development on any natural sl.ope that is twenty-five percent or greater. (iii) Parking lots. This category is defined as a land area or facility for the temponuy parking or storage of motor vehicles used personally, for business, or for co.tnmerce. ('iv) Sttt'.ets, roads., highways, freeways, and <lriveways, This category .is. defined as any paved impervious surface used for the transportation of automobiles, trucks, motorcycles, and other vehicles. I-4 June 2015 L__J ~---) L _j i j u \ ___ ! l__ _ _j Yes Yes Q} Appendix I: Forms and Checklists New or redevelopment projects that create or replace 2,500 square feet or more in1pervious surface (collectively over the entire project site), and discharging directly to an Environmentally Sensitive J\rea (ESA). ·'Discharging directly to'' includes flow iliat is conveyed overland a distance of 200 feet or less from the project to the f<'.SA, or conveyed in a pipe or open channel any distance as an isolated flmv from the project to the ESA (i.e. not commingled with flo,vs from adjacent lands). Note: ESl1s arc areas that include but are not limited to all Clean \'vater Act Section 303(d) i1npaired water bodies; areas designated as Areas of Special Biological Significance by the State \Xlater Board and SDR\'v'OCB; State \Vater Quality Protected Areas; water bodies desig11ated with the RARE beneficial use by the State \"X/ater Board and SDR\VOCB; and any 01l1er equivalent environmentally sensitive areas which have been identified by the Copcrn1ittees. See manual Section 1.4.:2 for additional guidance. No (e) New development projects that suppo1i one or more of ilie following uses: ~ (i) Automotive repair shops. This category is defined as a facility that is categorized No (f) [I in any one of the following SIC codes: 5013, 5014, 5541, 7532-7534-, or 7536- 7539. (ii) Retail gasoline outlets. This caregory includes retail gasoline outlets that nicer the following criteria: (a) 5,000 square feet or more or 0)) a projected Average Daily Traffic of 100 or more vehicles per day. New or redevelopment projects that: result in t:he disturbance of one or more acres of land and ate expected to generate pollutants post construction. Note: See manual Seclioll 1.4.2.for additiona(guidance. --------------------------------------------------------------------------------1 Does the project meet the definition of one or more of the PDP categories (a) through (f) listed above? LI No -the project is not a PDP (Standard Project). ~ Yes -ilie project is a PDP. The following is for redevelopment PDPs only: T'be ~irea of existing (pre--project) impervious area at the project site is: O • O ft2 (A) The total proposed newly created or replaced impervious area is: 648016 · Oft2 (B) Percent impervious surface created or replaced (A/B)*100: 1_Q_Q ________________ % The percent impervious surface created or replaced is (select one based on the above calculation): [i less than or equal to fifty percent (50'/ro) -only new impervious areas are considered PDP OR ix] greater than fifty percent (5U'}o) ------the entire project site is a PDP I-5 June 2015 r· ·, \~ - j L _) r ' ' L __,J APPENDIXB Hydrologic Unit Map And 2010 303(d) List I I --FREEWAYS --HIGHWAYS --MAJOR ROADS --STREAMS RICK 1 inch = 0.5 miles ·t · HYDROLOGIC UNIT FOR BRESSI RANCH LOTS 29 THRU 32 --==--==-----Miles ENGi EERING C OMPA y o 0.25 0.5 l THIS PROJECT LOCATED WITHIN THE CITY OF CARLSBAD Pl'l.E.PARED BY G IS SER..V l CE.S DIVIS IO N EXHIBIT DATE: 03/25/15 REC JN: 17169 H:\17169\GIS\HydrologicUnitBaseMap.mxd \ ._J )_ __ j L-j LJ L ___ .i/ L_1 APPENDIXC Water Quality Treatment and HMP Calculations L_1 r--, LJ LJ Li Bressi Ranch J-17169 1/20/2016 BMP BMP Location Description Cistern to DMA-1 Bioretention Cistern to DMA-2 Bioretention Cistern to DMA-3 Bioretention DMA-4A Bioretention DMA-48 Bioretention 1 J Water Quality Treatment Control BMP Summary Table Total % Area % % Permeable (acres) Impervious Landscape pavers 7.7 90% 10% 0% 7.9 92% 8% 0% 1.3 92% 8% 0% 0.2 60% 40% 0% 0.2 60% 40% 0% Runoff Factor Impervious Landscape Permeable Pavers 0.9 0.3 ~N/A ts1oretent1on Footprint Runoff Provided Factor (sq-ft) 0.84 1850 0.85 1150 0.85 550 0.66 247 0.66 260 Intensity Intensity: 0.20 Precip: 0.67 WQv (ac-ft) 0.36 0.38 0.06 0.01 0.01 0.81 in/hr in Percolation Rate · (in/hour) 5 5 5 5 5 H: \17169\ WaterResources\ WaterQua lity\SWM P\17169 _ WQ_ Calcls.xlsx ,~ 1 of 1 WQFlow Max.Q Required Provided (cfs) through BMP N/A 0.214 N/A 0.133 N/A 0.064 0.026 0.115 0.026 0.115 C _J :~.J L ; L__ j ™ 5620 Friars ltoml San CA 921 !0.2596 Te!: (619) 291-0107 Fax: (6!9) 2914165 11 t L__j APPENDIXD Details for TC-BMPs and HM-BMPs r--,, r r L_1 L_j r-- L_1 ( ™ 5620 ftiari ifoml l:l,n 9'.!!1°'2596 ieL {619} 29UJi(l1 Fam (6!9j 291 -4165 Nt1 !';inc Ck1ne By Checkte!By A 3' H ' ' ' J I_ i I./ i: j l, _1 ;--· l : _ I \_,_! ~!UH$ 111 L.J to meet tte:ttment .~-1 IP-C!iUT@fUJ%_ roof C!~t-@m. 1h: r-1 4-8 urban :ire.is fora $ can l .J in ;?iiiMgJ,.:tl!! i!l!il©ttillf'!l® it> bimfllhmtt@~ wacmty. f n <-,a,\u,,cu am:i dc!ratried tinuennnv,m::i. L,J f' "'-\ Chec;idl*t ftw Cut~ a meets or a Outlet or dr:nvdown timt:. 0 to 1 a 1_"_1 a a a ovctl:md. \ __ J _, j ~, r, r---; L·i ! ~ r, j • ' i ~ l -, i • >l __ _I 3 ! ' t c I ~ . .J u ;_ .J '-_.J \ __ J P:ar::mieier >,;i! mL~ depth oil m;;,i; mini:rlvm pbttt1iLF11tm rHe w low m:tintcA1:tm:::c 111 Can be laracts,ca,pe<J Cdu::rioo l& u1eh1", minimum r-1 l i,,1; i;:lt<!.T\,iJ£wt f~4' bs~.;:·.1;; bu.i.n:cH':tV:ITT:n fx.iluu:;1 •i:1)1¢, wd ,,i stone oz eoner;:te, ,t foot 1H111nrt: or ::m<l the r, l__,J :_~J :___J '~j outlets c:m be rn,ctl m :t:tt::l!L :md L_ J l __ I The ~ - J ttt'ntments: m m iii< area m Iii m:ntrm:nt m or m m 10 011 :t L_j L .. ..i L_ J ! __ / \ __ i l ___ ) in onwk1,oo mcdi11n with nn,rctsc:::u,eiJ I_ I LJ LJ L_J PNttttmermon ,,,,.,,,uu,c" n,ust be constructed as :1 set levet h mny neceesmey to LJ l _J L _ _j ---1 u L _j l._i L_j L __ I L. ) L __ j 0 0 0 0 a a a nn<l is dv::dt dnms are :,et so the unittrcam tlnm. ,_j !_J ,---, L __ ) c_J [ __ -! I,'-J L_j LJ u r~-') l j i LJ ~ t LJ 1 j <t t 1 ;; i r<>.:. '-(?M MJ>,J; t'h'V} L.J ' ) ; ~-. ..J i l { ' ' L_j L ; f-"l L_J L .J L_J r---i lJ L.J L__j L_J LJ J / _ _j Urban I lant etland LJ '--1 LJ L~1 · .. 1 LJ i_ J used on rium~rou:s t1ew o::instmctlon ;] S,{()fffiWilter Wii!:itf Wilteil" :inr1Hr::ii!r1n L ,.J !. j i__~ __ J L_) Configu '\____J r.,:,1',<>M«>ti ht">i'h•At'>l•nJ ll@w flif;}nlt\ilf is ub!e to lf1ii0W """m""""""'~ ""'""''''"""' the MWS linear can be used l_) ,_ __ J _J \.__, J (__ I '-' L ) r~-, u u \..:-! " " " 1 Pre~Treatment 1 Verticat linden:lrnln M&'lnifotd i I . .J I .,. __ J r~ M.lximias s1.11fate area treatml':nt cap.m::icy " Orlfict! plate ccmtmb flow of water ttm:i1Jgh to a lower the L.: .. J This t,adith:mal offline d!vers!m1 method c;:m be 1.med with the linear ln scenarlos where run· off is to the L_J \ _j stream. /f pl'losphoms removi!l Um!!ar. the l"l,,.,M.,,n- "'"''"'"'""' to meet ttie new Virgil'\lll Stormwater Management PrntH:zm M~imicnusBrus at -Water Resources Research Mtlng removal rates to 70% Total vM,,.,,,.1.,,,. ... Zinc, and more. -~--, r Medel i lreatm0nt Flow Rat\'!' / --, tJWS<l,.·4·4 4'm 4' fHlS2 MWS·L·+@ 4'%6' 0.073 MWSt:4·8 4'idf O.U5 MW!H,HJ 4'H:F (U,44 MW!H.r+1S 4'1115' 7U:' 0175 MW:H..+17 4'a U" OJG!i MWS•l+ 1 'J 4'x 19' :un MWSA.·Hi 4'1111' OJl'ill HWS,l.Al·@ \'l"#JC OX1G MWS-l<H? lr11lr G.34$ irx 16" G.4€12 r-·1 Model N ("'-~) MW5'1A·4 lHG rnn:i noo MWH .• ,u ma 50;{> HWS,l,4·B mt 6161 HW"HA·lS 'HlH 762! MWH,4·t7 4492 f/NH HW;:H+lfl 5117 1(134$ r-----, 1170& MW54.·R·!l won MW:H·®·ll 7554 15109 HW:H.-!i·ltl ,) \ f (-\ r \ __ ) ' a, maint0n111ce costs. man hours, lind with the MWS e\le't@<TW that provide no MWS linear is a seLt-Ct!!'!tl!lt'N~d t~ .. ,nm"''"'l' and effective pre·treatment. visit am:! various an benefit to rnmoval What's l'lflt sub;ittct1ed to excavatJon and in~ resembles '"'"'"-'""""'~ ) r---1 ,,r--··--i APPENDIXE Storm Water Management Model (SWMM) Results and Supporting Materials/Exhibit (Used for HMP Volumes Only, Refer to TC-BMP Calculations for Water Quality) l I SWMM Model Inputs Model Schematic Model Input Report Summary Storage Curve Calculations Rating Curve Calculations NRCS Web Soil Survey Hydrologic Soil Group Report Pan Evaporation Data '--_/ ;~-r ,, ) I .,) Bressi Ranch (Preliminary Engineering) .. Overall -Pre-project Condition {rtTl,S) ~rossi nun~h Pn.tl iminnt·y ltr.3utt~r~11r.;r• tJ 1 ·nav IOPtlOHSI fl.Oil 1Jtin5 l:Wll>THA1'!Cll FLOr! RO!J'l'!l:t; "Z:+AnT~.c;.,.n ,;rnr.1' TH11" nr.:PO!ll' S1'!\P.'l' 01\"l"E nt,!'O!t'f"s'l"J\RT-,!Ml1 t::NO t<ATE ... uim-Trne: saei'ii, _STMi, SI<!:£:> END P~Y oii~n 1sF.!>cRt_STEl' t·JE:T 5Tt.1' nwFsTt:P Rmifwa sT£1' J'\LLOW P0UO!t:d 1:~tnTlAt n1\,l\.u~1r:u VAHl,;OttE' .... S1"EP .,r,t;rrrmufftm s,·.:r r11 u sunrruu:;A 1:0RMA!. f'lC•i Ur1lTttl S!s.! I' STS:lltl¥''•1'/\'l'!i: ,otidi HAW ii;o1.wno11 L!tl;( Df'l"SF.TS HtN,...,'fit.llPC ( i>VJ\'10!11\Tlvt/l c:s GP.!:t!'.11 AMPr KWWt,V;;: oan~1H>i1 os,oo,ao Ott/:!G/l9S1 t\Sd'l0:00 ost:el/~ooe lj,()(l,00 Ol/il! 1~/n q 01 ,1r.,ao 00:15:00 G,t: o;;,oo l :(')Q; 00 m, FART!M, ; .. T-... •p1..l P~'lr'tlmt:t;t::-rs ' r-!carr;u.·,-n~r~,om.r O.U!ii (LilS tL163 t'Ll~~,. ).~;1 n .. ~,s \.~is.i {L~4t v:~o, lt.lfir-2 :'.l.l!S 009-3 1;:; iSU!lARfsr\Sl , ;Sub::a,d1:r.1mc ,: .. i iNF1'L1fH\7fO~H i'.~!b~(~ t,;~}~'t:'.(!Slt, ··,I;'\ 1-ru1£S£Rtts1 ,.;N'Ui~ ',11:P)!i'l') [!Ip;..fi'" t;O t:-.;irrm)t~ r:.:, ft;J~fi 'fyp,• ti frnporv O.Ot2 su:;:t .. n-'.:.n 0 tnvuet. .!Zl~V+ 0 lf!JUtt\'rt;1~-W,!~·r5 f\t,l4 r::rtn::s i\t.l l.,it;Kh ,\Ll.; IW\Pl i'tt~':V '.H1CI,</ V,lt~.'] int,l :ti C,1.t.::'h !)Oill . .t;:;: f/, !'!l?V (}. '.}$ Hydt\:u -,:; :~ t)ut.L'tJ l Type $.·Jrt!)1!,:'V 0.(;5 ;µ:;_:,,::_\;-: Sta,;c/'i'.:ihH 'tllf.t! St:?'H.!5 tH.HP.t4$tO.US 0.000 O OOiJ 1000(),000 l.:lt'lOCLOOO Urti t~J Hen~ SWMM5 "fot~l J\t'dil :1.J s l't,t'V 0 •• HO ,,im .. lr.,~,;r-; 0 t>ctZ<?co ~5 ?Cnt.~ Curb ~lltlth Slo,:c Lbnglh 661 :i. s () 1tout,rro Pc:tr.out:ettrt Cl.ITL!ZT $ttt)W rack Page 1 '· I Bressi Ranch (Preliminary Engineering) .. Overall· Pre .. project Condition , ;l-!odr; X C,;:c;r,J '! Ccotd \ __ j' r,,c l(HlO ,llOO lllOi}, 00() •. 1 i'J!:lt'r!C!::Sl ·t,1nk l! Ccrotd 't.··l:t~ru ic-,,ly:J::n!;./ . !it:HJ~:';".H· c;:h;i:c:·nt l <{-:,;.t:;.rti y t>~.t:rt. L~•:A i.>:?OO.!l!.hl )\10(} J(Y) ,,:m-isot.S! ., ,rn,gn lt'··Cocrd \' ,;'Qc,;'d ,;::.;:t:ar;~l\J,., !00.0.00D i,;;')C>O. roo ,--~1 ! ... I ,_J SWMMS Page2 , __ I Bressi Ranch (Preliminary Engineering) • Overall -Post-project Condition \~Ttt.J:I t,1,;;s:ii i!aneh ·1>rellr.:in,1ry E:n91no1:ring' .~ t 't -~~ 1:1 ~t}PT1t;,nS\ Fv·1~J tnJ!'T$ wnr.irn11-rtou t?t~'Vi1 f!OUT1NO $':;/,}t1 t'ti.1£:: ~TA~1;r1!1r:~~~ ~ .,1:ri~.;,,_s ,;,.,,._v .. rr, !\EPOR1' S'l'J\llT TH\£ END v11T11: - i:i!!!l-tHIS SHC:E:P S'l'i\R'T s11e:;.;,-rrm Oil\'_!l!\i'S it£PORT S'l'E:!' H!:T S'rtl' PUY-l!TlW llQfJTWO $TO:;> ti!.!'l'CW_PC!HUr:a 1 ~;Eft".i'tt,l,w~ t:r~MPltfU Vt,RJ l'sflttt~.;S1't:? t R~;:~·nfE't.iJt;..;/_ST!:.:t' t-:H; s1.mrt,R.:t, 1::mi:;,\L_Fl.,tw_LlMt'l'ED Sf'.t l' S7Z/\ll\' STt,.C toi~r/f_r<nlu_Eor.tA7I.CN hlfll\ Ol'rSCTS HWjiiLO!'ll r:.:vr,r-oru.rrnm en~ GttEf:rl /\;i,'1' r:.1uwr,Vr.z.: Ol:l/~ff/1951 D5,00dl!i \lll!~n/t~Sl 05:0(l:OU os1n120,rn ::!.l,00,00 l/1 l :t/Jl Q 1,00,00 O:lS:00 4•00,00 t,oo,o;j m P.A!l:T!,\L l) .. 75 (l U~'l'H llCl """ D!ol'r!l (l ~. Typo t~;;u:amote:rs- t~Y.cNt,i' r:o ! Rl'\W,~,v,1u;J /!~in Typu Ttine .snow tt:u::~"1 :e.~,1 t:t"ll,.? T:'?!,l J~Mk·l t!;unMttl\S~ VOWM£ !Hungage OCCijll!!ltla Oec.ana1d~ tJ1·~a~nHlde ()~l:!'lU1SHh:' t nt.r\t ! c~ t.Ch CCU t~C~ ()Ut l ct STOP.El STORE:;! JiTCf!H:) f.CC:l ·tor;.:iJ f<l:'(l<l 0.5 t'c:11t. !1r.p.tf:'V !HJ 69 G~ 9'(i ; ; 5Ut:lf.'"liH:Cfl~t!nt. ti lm;,orv ti l'ctv n ,~:pcn1 N,t·v r-ic:to-rn t(~.n..:: n.v .. 1 t'.!/t4 , 1!Wll..'11lNrI01l! _ 5 . .,bctocd1mcnt r·?!il LYM sron~i STORE2 1rr,:,nt.1 SWMM5 0 -01~ 0,·01::! 0.012 {LOtJ suct .. icn ~ \; 9 9 /'1~·;;, t. ~ ~ ~~\! !IW!ltt £h:.?v~ fl {l 0 tnl :it 0.()5 o.o~ 0,05 O,OS !lydCon 0 01375 0. 018'15 O. 018"/S 1'.l.OHi'/5 ChE:.f~iJ i 1'l'"In! mt::£ 11.:lX. ~ Cop th b ij :; !l. ()5 ,: .1 o.o, (·, l o.oa l 0 ,i!'5 I'. ! !Mr.'"""' 0, 3 O.J {)' l (!, J F:;.'~t,1t1 {';';;il lt: Ttrat! :1\.,"r'" E~~: lrn.t ~i;:..ort.t:~o D~r,r.h Cttl'Ve I) 1';\t:'.HJUH 0 TflDUL1~R () 7i\B!Jw\il ·ruh? Gtt~ t~· t:Wt:VO 1$ ~~ .i:S 25 Pnr,j;r.$ :;;ct sci SCl ·'Jtttl(!C. CutflcJ\.J f'.llltl'lt Pent.. Cu:.b S.nr.tw Width Slope tong th 1',1,:,1( :!Sil ~ 0 lO,, .. 0 j~j ~ 0 02 1 0 n~utcT\J ricc.ne)uted ()!J'l'l:.E:, O!J'tl.ET otrrt.n OV"TlJE'i' P,n1~l1id ~vup. l\:;'(l.l frn~. il 0 !l 0 () () Qr,dt/ Page 1 I i Bressi Ranch (Preliminary Engineering) -Overall -Post .. project Condition 1:.::-.JJ-~i ,,,,n ,,,!!-':, iC!J!lVl:.'.Sj ,; ;N,1.rr.u- sr;J SC] !HS!'OttTl t!ll'UT NO ('tl:ft'ROI.S NO 5':,'0i'H:1 .:rrosu:::? ~;iJUt;A'itHMnlTS All.a ;;JO!,$ 1\U, \.W!s5 ALL. ,HW) 0 1 :; 0 1 1.9 2.2 ;z.!IS J ~ s s G ,ts.Ci ;,c.:i t,t;Cl o.ooo~ o.un o. l(ll7 !l.:HOll 1,ll'D 4, -il;IS: ~l~~7lst i:• ns;; ·f.1. 75(~~ 0. ~J!Ji)J n.mne 0. l \tH 0, l~~:t l , 9 it!.} •l ,Ol'.l1i s. 01~.; Ht.o:10J ,D.:llG,i o.onoo O,•H3:: 0.0GOJ (l.2164 0.•170~ V,f,t,,J .1. :1 sa,;; J(i. 0-10:.". ·u,w 14~0 "l'!i)G -$4{)f; ~HO 6-lGi'l s.,r,(l U4f!HJ lJ[JQ n::r;, ,;;,;,a t;lOO rm1,::i1;; li]f/S O, DOO Q, lHHi WOOr.l, !HHJ moo i,). :;;)1) U~tic:s tt-on~ \COoRnt!-11\TUEj i ',;,)di! SWMMS (l,!)()0 l~OD. (HlO lVGt; ,fJ(W ;)Qt' '.)()(i f,). ils?i) \;\) ~.J') H 1',\tlt!!J\ll tt·r.;,rr1 n,;;1 7~\ti!JL\R/{JtP·';li HC~ 7;\1311l.Mtr/t:Frll flCl Page2 z J ; __ J ( .. / ,-----, Bressi Ranch (Preliminary Engineering) .. Overall -Post-project Condition JV!i:R'l'l<.'ES! ;.!..ink t;:·otyg,mal ,.Subenech~en~ x-coord C:1Ai C:~J\:! f':il\3 mv\1 l ;vr.to:·L~\ :: C!i!<J~ SWMMS ··1001).0CO lv!Hl-OM V 0:00 :U}iJl.L~{H) .:!lO(UlOil J'JQC:L 'UUO :z.~uo. oo-t l t;Ch~~, i}Qfi Pagel '_( •--J /, __ ) Bressi Ranch J-17169 January 20, 2016 Storage Curve Development Assumed Depth at Ponding HMP DMAID Surface Volume Area (ft2) (ft) DMAl 7,200 3,95 DMA2 6,460 DMA3 1,290 2,95 Assess Volume Sufficiency Required Water Depth at Provided Quality Volume WQVolume Volume (Volume-based) Sufficient ? (ft) (ft3) (ft3) 2-4 28,440 17,042 Ok 25,517 16,370 Ok 2,1 3,806 2,694 Ok Total: 57,763 36,105 H :\17169\ WaterResources\Hydromodification\SWM M\17169 _Storage_Rating_ Curves.xlsx \_~ . _/ Bressi Ranch J-17169 January 20, 2016 Rating Curve Development Orifice equation, Q = C,A(2gh)112 Weir equation, Q= CwLH312 Drainage Area DMAID (acres) DMA-1 7.8 DMA-2 8 DMA-3 1.3 DMA-4 0.9 Depth {ft) Low Flow Q (cfs)3 0 0.0000 1 0.1321 2 0.1917 0.2109 0.2367 0.2727 4 0.2745 5 0.3077 6 0.3376 Depth {ft) Low Flow Q (cfs)3 0 0.0000 1 0.0818 2 0.1181 ?.,6 0.1352 3.5 0.1575 '.L95 0.1675 4 0.1686 5 0.1888 6 0.2071 Depth {ft) Low Flow Q (cfs)3 0 0.0000 1 0.0432 2 0.0619 2j 0.0635 2.5 0.0694 LIS 0.0755 3 0.0762 4 0.0882 5 0.0987 Note: HMP Restrictor? Yes Yes Yes No DMAl Mid Flow Q (cfs) 0.0000 1.1546 4.1628 4.2627 5.9168 7.2004 DMA2 Mid Flow Q (cfs) 0.0000 2.6568 3.9903 4.1118 6.0502 7.5035 DMA3 Mid Flow Q (cfs) 0.0000 0.2030 0.3473 0.3598 0.5532 0.6947 1. Orifice toefficent = 0.6, Weir Coefficient= 3.0 Orifice Sizing Weight 43.3% 49.4% 7.2% N/A Overflow Q (cfs)2 0.0000 0.1342 12.9112 35.2218 Overflow Q (cfs)2 0.0000 0.1342 12.9112 35.2218 Overflow Q (cfs)2 0.0000 0.1342 12.9112 35.2218 2. The weir length in the cleanouts are assumed to be 4-feet. Pre 0.3Q2 (cfs) 2.254 Pre Q10 (cfs) Depth at HMP Volume (ft) 3.95 3.95 2.95 N/A Total Q (cfs) 0.0000 0.1321 0.1917 Q;2J09 1.3913 4.4355 4.6714 19.1356 42.7598 Total Q (cfs) 0.0000 0.0818 0.1181 .i:'/ 0.1352 2.8142 4.1578 4.4146 19.1502 42.9325 Total Q (cfs) 0.0000 0.0432 0.0619 . 0.0635 0.2724 0.4229 0.5702 13.5525 36.0152 12.518 Weighted Low Weighted Mid Flow Orifice Flow Orifice Maximum HMP Q Diameter (in) Diameter (in) (cfs) 2.3 1?..5 4.4355 1.8 13 4.1578 1 0 .~ 4 0.4229 N/A N/A N/A Total: 9.0162 9.0162 cfs < 12.518 cfs, therefore, Ok! Max. Percolation Rate (cfs)3 0.2141 Max. Percolation Rate (cfs)3 0.1331 Max. Percolation Rate (cfs)3 0.0637 3. The "maximum percolation rate" is calculated based on the proposed bioretention basin surface area multiplied by the bioretention soil infiltration rate of 5 inches per hour. The low flow orifice is sized accordingly_ to ensure that the required water quality volume is treated by the bioretention soil. H:\17169\WaterResources\Hydromodification\SWMM\17169_Storage_Rating_Curves.xlsx lJ' 7 IO'" lJ' 7 JrN I i i I I Iii J l!I <a ~ •159111 i~ J n ~ 419),0 ~ A Hydrologic Soil Group-San Diego County Area. Ca•lorn1a (BIIISSI Ranch) 41t,OJO 41'0'J:) •1119:> 4'16210 4lUlD 41'll0 4'16)9D 41'6QJO 41(0)0 4ll1SD 4"210 4lli,llll ·~ 4:'6190 ""11> Sc:ale' I 2. 960 If lfflll!d 0\ A lal'd;apl! 111· • BS) sh!l!I. -------======--------------==============>Ml!!Un 40 BO 160 240 100 200 a r,oo Mac! P1IJl!ll0\' Wel>Men:2lllr Cane' a:DdNIB, WGSIM £dge ID: I.JIM la-e l IN WGS84 ,,~ .... Natural Resources Conservation Service Web Soll Suntey Nalional Cooperative Soil Sun,ey 4"1M511 4114!1) 0 6SIO 4'6S70 47'5'0 J .. ~ ~ it .. ':: ~ I i i 51 I i 11111/2014 Page 1 of 4 lJ' 7S,H lJ' 1 JTN .i J r- Amlll !ll !nl@H}lt jACII Arn« o! iMITT&!il (AG!J S@H& Sl;;l! A11t!!ll) f>@lyg@rt'1i A A/0 -a aio C c,o 0 _ Ho. r&lwd w nn\ &vilHilil * Snit fldln@ Un.;s -A -ND -a -010 ,, . ., C -CJf) -D No! rr.1@6 Of Ml ilVEAMHl SoH Ra!ing l'dnw 0 A 0 ftjt} C a 0 IJJD l ] r. '-/' l J Hyan:11og1C Soi! Gmup-S;;m £Mgo Counly Area, Caiifomi@ tSfasm !1!ancl11 0 C CJ Cit} C o O No1 .al\'ill w NH awuit!U0 Wzliilr 1'e111urH S.!!®atn:s ilnti C@11;t1i Ttil!l$JH,rtailiMl M-t Rmb lili$1%1Mil i1ql1wilfE US fl!hlies Mi\/Wl<Oi\©& Lnro!RcactJ JJath!ltoiJIIG Jwmti ?Mhi,.mµiiy Yte 1.mll surveys Ulat wmptisa mapped at 1::Z4J)OO. Wami11g: Soil Map may not N va!itl al !his sale. EnJJlmem&nl cf nuJOR 1Jeyoml lhe scow Odtl uuae delaii of mapping aeoumcy of soil Erm p!neameni. Tnn m&JHil de no! show lno sma!I ,Haas oi con!railli/19 S-Oils !hat cnilld have been shnwn al a roor.t delailed SCilku, PJe;;se tely on the uar sca!-0 011 aallh ffil} sl1e&t for map t11aasu.emea1s, Seurczy nl Maµ: Nalura! 1irum1Jrces Conservnlion Sarwi£U W@bSoil Coortlin&le U!'?L. imm !lie Web Soil Sunt@l/ are based 011 !h@ Web M0,~1or "'";,..,.;,,.,n, whitll r:ires01Vell ctirecilon arlo :shaPf, bu! @i&lnru: and .irns, A PHt/@Clion lit.it m@a, such ai:i ii,,,, 1ua!,&1t%1 used lf room accJJfaie cak:u!allm1s ctdisl0n.;e ur aiea are raqwnircl, This pmd!Jci l!. i;,eneralett from !!Ju LlSOIH-JRCS cutifiuct a;iJa as !:Ii Ille 11.irn1i:m 1:lal0{sl lisied i!elow J\jQ;t, O@la: Area, C@1if0m1a £OU Soil roai,1;i111ure li\beied [ill\ spa;;,; ,mown; lormill)Jcales i:5©JJOa tl¥ larger Ome{ii} iumal 2010 May 3, 201f>-1un 19, on whiJJITT !Ile soil !mus wem imm the lmJJ)grourn:l mnµ£, A1, .t 1esuli, m:nne minor shini119 tioumlariu mww bl'!; evident ~a!ura! Razcurcu Web S-0t! H/Hi2!'.li4 Comml'\la!l.m Service Na,111,,al Coaperath1e St:Ney Page 2 ol 4 --, ,--·-., HrC: -~l LeC ~-·-i i_,j , _ _/ L I Ga@¥TGta :sanuy !nJM D to JG pf)·tenl dwp0:t H,,erhH&rn to \I i) s1q:ws Fkw~is t&rn:l, 2 tAcpes firv:1 p1m::en! 2GA I_} l ___ J L .1 The soils in thrr Unlied Stat,:ns are e,~,snncu, io four groups and and lhree dual classes are defmrsd as follows; A, Soils infii!raik,n rn!e wet Thesrr co0sJst we:!! drained to ,ZNl.,r;:;;:;,v,z,,,. nr'"''""'" sands, These soils h@va a fl SoHs (:Q11Si£{ Of rl~r,tlr,r51A!II St)ilS lllzl YlBVB ,mm~"-""" h&iV,9 wet These well dr;ined or v11eli 1:lrzdned slow infi!trahon ra!e wlHm wet lhElSI'! censist lhat !.he downw::m:1 moven1ent of wale; or teidurn. Thes0: sods have a slow rate (1fwater wet soils !hat have at or nesr !ha surf0ce .am::t soils thal oue sh,:ir!ow over These so-ls !12ve a very slow rate of v12tec i ansrn1ssion Ha ;;oli .s lo a dual qroup 8 0 the firc:;t letter is for drnH1ed z,reas and the second is for un,lra1ned areas. lhe soils lhat in their natural comiit1on ar@ in 1J 1:11e kl dt10! classes. nnmrr:,rfnn MethCJd: Or,minant Condifa::m Pf:rc&n! Cuict'l' Ncme "'JJ'c-1...,.-,rtv _j I__./ l __ j ',._-_) :·.,-~·:··i 't ?C:~ra Ft,?~!ff j ;-._ :Ft(~ ... , t.tiJi t1t-t:,1t;·(:;t tid·/r:i, ~~ t~~t :~1·:~~':t_:: t,i{tWil 1/:.i\t .. i··.'.;';Ht ~~:r~·tl~tn.:; t-tf.Str LtmFhLt .} tf~<ii tt.;t.s:/.f {:,Mt .0.~~-x--r.;,:_/;Fr~i,rf.J~t r~;~·!P :·;;:;: t-.'i' t'·t,.~~l:;.-Vf Pl"','t nf·>· Hf ::·;·/ .. ·:·: n .. ;,t ~ :-~.;i .. ~it I nx :::1irnt~ ~.,,-;t~T ~ ..... P.r .it~ ~·J.}t L.. L ~ ;:t~···,:·~ j f•.f ,Ht): ! ,·.!"-:':·1 f:.f\{·itl".; ~ti·-~~- ': ,. ;; ! l l (:-:H Vl.1'rA n.i ti~~- ···· 'F Nvt l 1tt>•:ChVi 111:;-trH:t-1· J9:lS .. 1~Gi \9,1~ ... t·J1\'.; 1~q.tiij~\1J}~j 11:t4t1=2HfJ1 i~P~D1) i ;H ·;·<!G)~, t(H;i ... l.OU.~.: l '.J~S. ... 1917 l~H<,Ot)'; i%;H~1:; i l.oJt,;~1 :l'J:) 19·!0-~·'.it):;: tl'rl...,JYrr !i~J},-,,)(j~}~ 1 '}J7,-.,?JH;~ i 1 ~::~:\.,.<:.:i:·r;-: ! E_·1 ·\ ) ... ~ !~ i "1 '.li,,t-1) iq 1 ::1J \·"'< ~~ij1 l ,"i l ·1-~: t O ! i ~) ~.;,-.~·a.) 'l 1 1 ~$~ ... 1~~~ L1fi~ ... ,1s-;7 uno-::su:i 194 E • :;>,ni', % l ):'...'1 ... } 1 Fi) tr;:;; f, ... ] ~~~) ~1,M0 .. :1~1t=:. ,1 ·" ~ ... ".··:;J~ :. ·.:;.:: ... f-:k f 1 ·';.i)--··.Hr• l -t ~P ... t -~ <, t 1::ti1-2n;;r·, 1~.;~~ ... !~Jn~·= 1 f}$:J .... l\ti?2.· 11;;:5 .... J[.1tj:'.; t:J:5} ... l~fli ! ~t·J,;-...:!on~ t 1::, ... ::ont 1 r-,.; fl.,, i ~~t;i~ l JL .... ·,-·p-1)'· 11~ .. , ... ~~h;! l ') ., )-..:;,!'~·- tt"Ft.-,."·t, ~ Si :' r. .... ~o tt;.R «,..<;1V) ; {~.;;f,,,. 'tt v· ,,wll.\'ll'tc.dr,.edu,h!nlftle,1fv..{!.~!evap.r,ncl.html#CALIFORNIA L~0G n .'t!i t!,,l(I 1 .1~ ~t. (}C ~~1~ {,"$'J fi~nt, 1L Jf ·i.•1l ij.~, e~1ti 10.oa 11.,0 10.ob 4~61 1~73 lJ.08 11-6G l0.70 7L J~ l;.L.Li~ lf~~,·~ HJ.tit 1iJ,.3i 9.DO J1,t~ IG.1! !&402 J5,9~ SaOl ~.40 8.15 10.fi4 ~.;1 ;j,.-z.1 1.1;0 1.:n t<} .. 11 HL!j5 !1,fi.? =i~~-,~ H.-OU \L2.'.: !~~~Hi il,()[I CE! 'l.$2 HUH \l \)'.; '1,ti;l liL~~l 12.~'} t:'L~;l t:.tG2 &.01 ~-,~ ~-~1, ;~~~ e.)~ Jj. J') 7.)0 B .(i~ U.f·/ iJ.,4U ;),(>) 1.00 {~" ~ l '•,:~ i},tlil '.i .r,-1 s.10 i ~. ! (? ; • ·is f.&1 J • \IS ~ .en !i.Il ?Oa9B 10.ifi JJ.9~ ~~1li J.J~ ?} .. :1 frt!5 1v~S ll,l4 10.!1 7.~9 ~~JB 4 .. ;) 4~01 J~~9 ,.'), ,t. ic 9.n 1 •. 15 :?.2G :L2l ) _ .~ J. !>, ::!l ·'L no s .. 1;1 i.i ~ DU j. ~~ ~, t •i:? ~ .fl'i ~,:;i 12.01 11.!d 11.41 1.fG 1.~2 io.G~ u.~3 G.dd 1.:.d r~, n; "7,fl~ 5.!.:S .J,,Jl ~~ » LJ(J tl .• Ot ~ .01 ~~ g '1 G, !,; fJ_ "t'.J 4.3? .; ,HV Si •11 3. 'J 1- tL 1G ,l, i;r, 1.1t; 2.Qb ,t .. H~~ 5.1t •• ::u ', :23 .'.;,.1,) ftUl.j LO} l.H :i.(H ~1-Vfi l~i1 LJt~ ;:,. 1,i '!' ~fl; "' ~ ., <,f 1 » [}~) 't] L-il~ i.l, tJO 1. .1.5 1 . ::: ·~ I, :;r, (i ,(:ff ;1 ,1-n ! L1.0: t %.? ~ :"t[) '1°] ,()0 .:~ t ?~ ·r;~..!J lHL\4 .. ~.sn 11. t:~.1 'G ~ tfr './9. )!', /,~ ... 1 J .;s .;lJa J~!S ~.?Q !2.1.l 11.05 14.;~ l).SP £0.SO 1.fO J.1~ lod~ _}, .H"t ;!~tHi t .. J: n. -~ 1,~.a?.1 <.1; 1,L).1 1tL;.1 ,;,,,·H~ 1.~r L~·.1 !ts ;}~ )? • i)'; 1 .Ji,t\ '~ : ~ r~. ft!', g. , .. ~ 1 ,1, r ., ., ~ . ~;o Hi. :n ~., .. -: .; .; ~ ;fi2 .1. fd ~ :1r, LL; J.t! ,t.U~ 'r,,11 ·f.,Ht ~Ji,~~· ,;~·~;;1 :,.rq '.\ .. (,l 1.]~,. D.f~; rt.;~ i,H;i ~~.)7 -L:n: ;,,~S \\ .~, ;~ O,'!~J '!J~-i-1 ;;~-~(i _L·U f.!~!.iS s.:.;;J ,i:. ~ •. ;.A fJJ:!t; '.J.:,i tH.:,; ]!.~. ~ ~!;,~( ":.~~ !.2~'.i: ~~ .. ~;".. ~~(i"~ -:,>L {;_('(~ t.L.00 t·.:-:. i).(l,tj ~;~f (.r~4 rj.l(~ (,,fit ~,~.d 1.~,!) (~.{l~~ (! .. (tt, -~~:.s:-;i (:.~)ft O,,,;;l C'1+DH 7~:?G ~L;f1 !,~:>.:1li 11sli?i '.L0.: tr~'(i,l O~iJG f,JHJ ':,t~ .. -:Vi :.~'f'J 2.,fi~i ~~.~n ).J} l·L~fj H\,)l i~.r,; l\l,l~J Lt.4G 1,£:,0 '.LO,; 1:·~-~ lFJ.1!, LlO j i, :.o l ~ C·.'3 i) ~ H0 l_.A'.! : .. p -~ •. : t_! d,Oi B.GO 9,?J 10.tl 1,11 ~.:;.~ !~1~ H.! ltL5$ 11.d:'1 t!L~J &.~5 e~SS 10~44 11~12 t17t D,J~ ~.J4 JQ.$J ll.5~ J0.22 ~.so l~l3 99£0 10.a2 ~.~5 9~91 13.~0 15.Jl 11.21 lij~OO ~."1 1.:.,, <LJ(-n.:;r; rn.n S.~j 1r1! 1.a; lt.JJ lUiJJ f;.{:{f I l--B7 '!.H 1. !'J t ~ }~1 ! l. ~ ijj ~~ ~ ~;If.) .j, 00 1. cr-l ~,i..? st~ j:: ~.ls 5 e?.fJ 1,, -:H~ :.! • ~~ ·;:, .i.10 f.·t.~h 1.·;1 ~.,i,~ !,~}-1 t1-.f\~ (Lit~ ,;,t;1 2 . .'i,j ~~ 5.11 ~,!h 1!.q~ 11.~3 1:~1? 6~9i ~.7~ 1~J) i. I6 r~h~: ... 7 ~,: HL.t"! L:.:<; !L1?. u:n. &.~:: v,:: .. ·J ,1,-12" ~-.. ~! •t -·~~· 11.e~ ;,r .. .,£ i~:,'.!2 s,,.~J :,4f;J i~rn .. ~i: ; .. ;;:i :.·~:; 1,--;,3 i,41 il .... :rn G.1.~ :L~tJ lw~;-; '' {)1 !.ii;) L'.t3 Lt~ 1. Ct ),SJ LOB l. ~:: L.:?ri L H~ 1.02 'LS! ( "/i '>,; l ~.;;r !t,'~ :i ·;·,h. 1(LJl1 tj, i};. ·1.n:; a.t/J t.Lt~ t.~,,·;~~ tiL.~H 16~il-6 1z.tq '}.l)~, "J.~t~ ~1 .. 1i 1J,.·tG FLJf., 7.~!* s.~1 q.~1 111.1~ 1u.o: ;.s~ G.so :i ~ l 1? :; , f~ti •. : •.~ti t, i'i ·1 ... 1.:, .j. i:<~ ~. ~f.i ~-.'0!1 :L:~'.'.l l.~::t .L f.J' l. ~W tL ·; ·1 11t.n t(P ,I);; Ui:t, l r Gt~ ti ·1 11 l .${k (d ,4"! li:'L~6 H>~ i.1~) ti:-_ J;; 'E:.~6t; {i':1-,. l ~ tli.:. il-l c~.riL'.:. (i.~:u (Lf,(1 -Li.'' ~L,,:; ?~1~ S:.J~ J.111 Lf,.7 r~.uo (Lc.H/c 2!~~5r~ ::;, ... 1~ \'",,),) 1L~tv ll~{q l~~~n 1\~.71 1~"::~~:a 10.t,~ t~~' 1:,9'? i. Hl t~r.~ut n.,1t1 Q.00 ?.~J l,~a ;_~ij ~.12 10.&1 9.1~ ~.11 J174 0.~, o.i~ \1.t~ t),_c·; ! . .fiQ ! .. '1 .;.,iJ t .. f6 rL.1:; ).":1 i~.1:•1 ~.l~-i .;1 ... ~u '-}.'.:n O:.~·l :;~LJ:: n,r)u o.~JO d,:)0 ·L!;(:; ·1-:,5 ~.:,~ 1LJ-2 0,S.'.J fL$H :L4~ nf~H) fLthJ ,~:J.0{ 1. ,B 5 •. ~1~ ~-11 !,;1 i0.:·1 1.~B 0~1~ !.71 1.iB 1,1·~ ~, ~~ ·:.:1a ,~ :,ii r~ .. ~~J +1. :d ::~.;:; ·L<.:~ ~~.,::-"ji~,;;:; !J .. \)t ~.t.P ~J.t.: ?.\·~"J.; ,'t •• ,) ~ ... 1 r, 'i.j. -,, .. it; H:.t~-~ t:·.~, .. fjtf.il ii.,.\fl }~~D .'. .. lt'• 1 .. :U t.~ .• 11~ 1. ~!.";':} 1J·'} .. ,. ;':. J9.('.,:; lL'i) fL~H-i ,t . .1i) :~ .. lD-t ... l7 =~ ~ 0LU!i t1»'H ~;_tJ:; ~rJ~u.-, G-~D (i~2?: :~,,Hi !.i-~ t~,t£.: .·.d :.;. ';\ -~, '.i ~ • .'.;,(:;. ;,:\·, fi.O~, ~:. J!J l,!n {L7\ fJ,.•}; 0, ! r I \ __ j L-J ,_ I l I SWMM Model Outputs Model Output Report Summary Flow Frequency Curves Flow Frequency Summary Table Flow Duration Curves Flow Duration Summary Table Lj J -. __ _( , __ _J \_.J L_J L __ .J l ... 1 ,--, _J ~--, j l_ __ j __ ) C J !\ fL ,·,,t (_.) I_) l_J r-, ml - Peak Flow Frequency Curves -Overall Site 14.000 Ql0(12.518ds) -- - - - - - --- - --- - - - - ---- - - - - 12.000 10.000 QS(10.185cfs)~ - - - - --___ _ - i 8.000 ·= 3 Q2 (7.514 d5)-~------------------- 0 ..: .IC 6.000 "' u c.. 4.000 -Pre-project Qpeak 2.000 ... Qlf(2.254cf5)-- - - -------=-=--= ----'"'j -Post-project Mitigated Qpeak 0.000 0 l 2 3 4 5 6 7 8 9 10 Return Period In Years 3 7GG L_! L_J l J ,--· ·, -'C -3 0 u: 14.000 12.000 10.000 8.000 6.000 4.000 2.000 0.000 1.0E-06 1.0E-05 - Flow Duration Curve -Overall Site [Pre vs. Post (Mitigated)] \\ 1.0E-04 l.OE-03 l .OE-02 % Tlme Exceeding -Pre-Q -Post(M,t)·O 1.oe-01 1.0E+OO r, :, __ J \_J L ........ .J ,-1 :\...., ...... J L _ _i i __ j I __ I ' l '_J i'":l'i,Hand1 , 11169 '_;.4 I,\ Interval 0 I l 3 4 5 6 7 s 9 lO l1 12 13 14 lS 16 J7 18 19 20 21 22 23 24 25 2G 27 18 29 lO ll 32 n 34 35 36 37 36 39 40 41 112 ,13 •14 45 46 111 .:1a 'I:! so Sl s, S3 54 Low,flow Thrc1hold: lu% O.l"Q2 jl',cj, 2J~4 cno (Pre): 12518 OnJln.lle U: 10\J lnuamcntal Q (Pre): (U0'.264 Tot~Hlowly 0~1~: 497370 Pre·11101ect Flow Prc•prc!ttt 1-!auu (thl :t254 l!O 2 .. :m 293 2.<159 276 2 562 l6!i 1665 JS! 2767 u, 2670 t.Z.2 2 973 211 3075 ll!S 3178 lBS 3.2!!1 177 3.383 172 3.48G l!lS a.ssa 152 3.691 141 3794 129 3-B96 t!S 399!1 117 4.!02 111 4204 W'J '1.307 97 ~.,no I !13 ~-512 91 4.615 90 4.711! 97 4Jl20 83 4.923 1a s.02s 74 S.129 n S,Z31 69 5333 6.G !,436 60 5 539 ~7 Su41 54 5.74,1 52 SB47 50 5.949 so &.052 48 6.154 4S 6-257 42 6-360 ,12 6.46:!. 42 6.S6S 38 6668 38 G.770 37 6873 36 6.976 35 7.078 35 7,181 35 7.21i3 34 7JS5 14 7.4B9 H 7,591 30 7,694 28 7.79i 18 ,r1 c/1 ds hours The proposed !!MP:[._ _____ _, f'!<!•p1t1Jett % P1nt•prc)ec1 Post,praju,1 % Pcrtentagc P~n/Full rl"1e Eiccctl!ng tlaun Time f>cemllng 6.23E·(14 31 l 6.2S£·04 100% Pau 5.8:JE,0,1 n.-i S.9tE•04 100% Pan S.55E-O.t 271 SASE·o.1 98% Pnn 5.33E-04 ~45 4.93E·04 92% l'~n 5.0!.E-04 223 4,•18E·04 a~% Pan ,U7Fi,04 ,04 4.IOE-04 ll5'lu Pas1 4.4uE,04 l9l 3.S~E-04 !JG% Pa~i •L2,1~-04 182 3.65E•04 86% Pais 3.921:,04 171 3.ME•04 88% P'a11 3.'i!!E·04 157 3.16£,04 lM% Pa~i 3.5GE,04 146 2.94E•04 82% P~n 3.46£.(!4 142 2.86!:•04 BS% P3U 3,3ZE-04 ns 2.7tE·04 . 82% Poss 3.0'1E,0,1 W!. 2.47E,04 Bl% i>~n 2.BJE,04 116 2.33E·04 82% PMS 2.5%04 104 2.0%04 Bl% !•,us 2.SIE,04 IOI Z.03E-04 81% l>a~s 2.35E·04 94 Ui9£.04 80% l',US 2.23E·O<I 117 1.7SE·04 78% PMS Ul!UJ,I !l2 !.6SE 04 82% 1',m t.%(,04 78 1.57E-!l4 80% Pass l.ail: .Q.j n l.45E·04 77% Pa11 l.BR04 70 !.'11E·04 77% I Pa11 l.!llE-04 66 1.37E·04 76% !'au USE,04 61 1,23E-(l-1 70% !'an l.Si'E•04 56 1.13£,()4 67~, Pass l.S?E,04 S3 l.07E•04 68% Pass 1.4!:!E-04 48 9.6SE-OS GS~, Pass IA5t•04 45 9.0SE·OS 63% Pass l-3%04 ~o 1!.0~E,OS SB% Pnu UlE-04 37 7.44£·05 S6% ran UlE·O: JG 7.14E•OS 60% P:i$~ l,ISl:•04 36 7.l4E,05 63% !'au ! .OJE-0<1 3~ 7.04[,05 65% P,UI I OSE·O~ 32 6A3!:',05 52% Pan UHE-04 31 G.23E-OS !l2% l';JU. ! !.D!E-0,1 30 6.03£,05 50% Pas1 :Wit-OS 29 5.ll3E,OS 60% PMS !l.05E 05 2a S,53E·OS 62% Piln tl.il4E-OS is S.03E·OS 60% Pit:SS 8.44E·OS lS S.03E,OS 60% !'a~! B.44E·OS '25 5,03E,OS 60% Pnu 7.ll,IE,05 25 5,Cl3e•OS 66% P,m 7,MEOS ZS s.03E•OS 66% Pm 7,44£,oS 24 4,83f.05 65% P;us U4e·05 23 11.im:-os 64% P~s~ 7.04E,05 23 4.fi2E•OS 66% Pau 704E OS 22 4,42t•05 63% rnu 7.0,t£,05 22 11-41..0S 63% P~ss 6,84E,()5 l!l 3ll2E-OS. S6% Pall O.l!-1E-ll5 lf.l 3.!!2E·05 SG% PaH 6 63£.1)5 11 3 42E OS 52% Pass G03Ni5 15 3,22E-05 53~,, Pan S.fl3E,OS Hi 3 neos S7% Pan 5.!l::!E-05 !6 3.22E·OS S7% Pali \ __ ) I j I \ __ J L .J n l,_J --, ' -, !iles!i R;rn,h ; !71!;9 ! 1-414 lntcrv~i 55 56 57 sa 59 to 61 62 61 u4 65 -06 61 6!! 69 70 71 12 73 i4 75 16 77 78 79 80 a1 Bl S3 !l4 BS BG ll7 88 as 90 91 92 93 94 !15 96 97 sa 9!1 100 l"re,projoct Flow tds) 7.!l!l9 B.002 B.10S S.207 8.3!0 B.413 8 515 8618 a.no 8.823 8926 !l.028 9,131 9.234 !l.336 9.43!:l 9,542 !l.644 9.747 9.849 \1952 lOOS5 IO 157 lO 260 10363 10.46S l056B 10571 10.773 10876 10.978 11.081 ll.11!4 11.286 il.3B9 I 1.492 l!.594 11.6!17 ll.!!00 11,902 12.005 12,107 12.210 12.313 12.415 12.Slll rre-pro)oct Houri Prc•pioJcct r. Time bccedlnc 2!! S.63Ml5 21 S.43E·OS 27 S.43E•OS 27 5 A'!E-05 25 5.03E•05 25 !;.03E•05 22 442E•05 21 ,1.UE,05 21 a.ne,os 21 ~.,lE·OS 20 A.OZE-0:, IB HZE-OS 16 HZE·OS 16 H2E·OS 16 322E·OS 16 322£-0S 16 3,22E·OS 16 3.22£-0S 16 322E,OS i& 3 22E•OS 16 3.22E•05 t,1 2,1l!E-05 13 2.Gl£:-O!i 13 :t.1m,os 12 · 2,11E·OS 11 2.2lE•!lS 11 2.2lE·OS 10 2.01£,0S 10 201E·OS 10 2 OlE•OS lO 2,0lE·OS 10 2.0!S,QS 9 1.StE,OS 9 l.SlE·OS 9 Ul£·0S 9 1.1m-os 7 !Al£•05 G 1.ltE·OS 6 l,llE•OS G 1..W:•OS s I.Off OS s L.OIE-05 s l.OIE•OS 5 1.01£,0S s l.OlE•OS 5 l.OlE•OS Po,t•ptoj~.I PaU•prolect % Percem,igc ?,m/fnll llours Time Excecdlnu 15 l,!llE·OS S4% !'au 14 2.B!E•OS 52% Pan 13 2.G!E•05 4B% Pan 13 2.!ilE•OS 48% Pass 13 2.6!E•OS 52~ Fas~ u 2,61£·05 S2~ Pa~! 13 :/..6JE·OS 59% F,m n i.&!£·05 62% l>au 13 2.61E·05 62% Pa11 13 2!i1E-OS G2% Pas~ tl 2.4l€10S 60% P,m 12 M!E-OS 67% Pan 12 2.41!:,0S 75% Pass 12 Vllf·OS 75% P~!! 12 2.4!E•05 75% Pass 12 2.41E·OS 7S% f>~!S 11 2.21E·OS 69% Pass 11 2.:m-os G9% P~n u 2,21E·OS 69% P~u to 2.0lE·OS OE% Pa;1 10 2.01£-0S 63% Pa~! 10 2,01£,05 71% Pn~$ !O 2.01E·05 77% Pan HJ 2.0!E·OS 77% l'3H 10 2,0lE-OS 83% Pass 9 Ul!UlS S2% Pau a L&ll:·05 rn, P~H a !,61E·05 ll0% Pan a UllE·OS BO% Pas~ ll 1.61£•05 BO% Pan a UHE,05 SO% P~n 7 1,41E·OS 10% Pan 7 t.41E•OS 7B% Pnu 7 !AIE•OS 78% P~n 7 l.41E·OS 7811. P~U 7 l.41£•05 751~ l'JSS 7 l.41E·05 100% P,m G l.21E·05 100% Pall 6 l.21E.OS 100% ?~JS s l.OlE,05 ll3% l'aH 4 S,04E·06 SO% Pan 4 S,04E,OS 80% !'ass 4 B.04E•05 BO% l'~n 4 !l.041!•06 GO% Fau 4 S.04l'AlG ao:, PaH 4 B.04E•OG 80% Pan Reference Material for SWMM Parameter Selection r 1 ,--, l1 ,1 ~-J t~J L._J LJ U nitticl States Erw!ronrnenttll P,o!ec!lon Atnnn,,11 MAN ion Rossman Re:1,otm:::es Division Research OH 45268 !. j L.J L_..J (,__J I , ~-1 :.......J ;\/2 SlJl! Charact©ristacs Sui! Te:1ture l{ Sand 4 7,! S:mtl ! lS tcnm UA3 tisxHn D Sil! LtLm, 0 26 loam i1Jl6 (UM (U)4 {L{}2 0 Ul nm t\ 9 FC \Vi' frm:tion {};;w!s, WJ. tl {; ~F ' FC \\'P tL4J; G.D62 0,02>! 2Af! OAll \} i D5 OA53 I !Jii {Ul35 :uo !l463 {J.232 !l!! {t501 !},,28;1 0.!35 {L31JB 0,144 iJ. I Jf} lL:7 OA64 OJHl (Lll!7 !1163 OA7! U :},sl'.2 o:mJ {L33! (L!2l l ! 0.470 l 2-.b{l {l.475 0 m!\1 ,, H19:LH6. td wctt,:d;md unl\1\;1,wd mitt cmcm ol n,tler, er soils% i!h n1cv1t:rn1,:n fr,e 10 line ic,1mcs, r .. g., slnllnw innrn. l-_.....J lj '· J L.J Smnnd1 \!i1rrn1:u Ci.1st iron gcslthic ct lUH im:hcs inches 1nebes 01! o in:: \l OI tlJH4 0.01 Rcsidnv CG\ n· ;{Jn ,, CL! Shim, Dt:n1~ m11.krb1 vs!\ unJcrbn1,J1 tvh:l'""11cn, i{, /\thtl$n?stcitiou~ it {L24 DAl r--1 \ _J L._J L.-JI Snow C;11ch Fac,0r Dnt:1 lM FllE ·FBe N;imu • Sta1l0n No. • Rain Uni:s min gngc rnimt, Horlzm11;i! !m.:at1m1 nl' the r 1i11 bLmh then th< rnin nnl blank ibcn lhc min gn;;c CHci; th\! !mHon {or press min Fnnnal in which the rn1n 1!:tt:i :m: Jf!d! ll !di l:VTt::NSJTYt ttidt rainfall vahit i, nn ;ivc,ngc rate in hzmr over !ht f/(n UM£: cm:h r:,infoll , ,due is 1h1: ohm,e nf 1,;1in 1hnt foil in ,he im:fa;s or CVMU!.AT!f/1£: cadi wlniwH cihw reprc:.cm£ thii cmmil;1fr, c rnir1fai! !hat osnmcu sinci: \!hi stan ,,,, 1 h;; last scrks of nm1· ,,:,:ro V:!IPCS mtht$ Gt !i!ltL )1llt'.fYi\l bdWCUl :;,l!;&t: 1 c.1,m,11,,, 10 t!dlt:f horns m !wurs:minn;cs fomim. 1'L1m0 of i:mc !;i;fic, whh rninfo!l <lnrn ifD,Ha Smirc0 selection k:r,c bLmh othe!''\\'JSC 1.nlit L./ L .i r l Name 'Jag Raia Arca \Vit!tb /'irca !f h:ft blank ,hr.m tbe subcnt;:hment wiH the n:G[L V1:rih:0i !m:a1km t»f 1h0 rmhcntd1rnem's "'"""'""' !d'i blunk !hen 1Jw :,ubcmdm1nl\ ;;ill or cm,J1,.,u•~1ci, subcnlc1m\cni'" rwmff. Awn of the sub,:aidmten! fnt s!wc! !fov, inrfoti cs!imnw oflhc ch,l1,1Ch!f!o!k 1,vk!lh is lhc ;u\r:a1t:1m1em 0n:0 divhl::<l l w ;t\;;r:tgis ma,imum m•erhnd flm, Hu: Htinimum merl;md fkm Of !he fltF\ ftent !JW !!JC fm!i\::q IH\1,!!L\1,:F ul the tubcn1d1men! before th1c 11,m dhmne1ize1J :v1wdmum from strn:ral difforem ,m:i:,wme now sltou!tl rdfocl s!uw flmv, such ::;:; n 0, 01hnil jfow ,rnbra!ehmen1 (see Set:linn A.6 for or now ;cr,ns«:~irm s1or;1g1: on th<: p1w, ious snt:ca1dnnc!l! Ondn;s er mWimt!thl {>I!< Scciion i1)US i\t<it 1.\ ith HO ,h,,,,·,•~~,.~n Slo,ag;;, t>f rnnaff bch, ei:11 ant! ! M l'ER V: runoff !tom rwn PEii V: nmoff frnm ~nea flows HJ DUTL ltf: nmnn from bo1h :irc:is !lows { J \._ / ' J I ) l ,I '.-·-1 Ch;h 1!w buHon press pacmwt..:n, fbr the subct1H:h11t1:nL Click Hvi humm !_or press devc!ornncm c,mtmls in !h,i L __ 1 I , ' J I _i '-I !nve;t [1 Tick Fix.:J !'id;d i'fom: !';'re nr owr111 comlliinn: mi!iilll slwg1; d1;1em1ined U} minimum flim !low ,;cmluit NOlMUl mgfolJ Fl:llJC b0sud on in conduit F!.\'£lJ-ou1faH tl:\!41! Sd ;i nx,:d v;:dut! r!lJ,41, l}UtfalJ :;1ag1: cf f!M£5,'f!!?!lf:S nv1fail \\:mer dcv,t1i,m l':r; ,1 F!X£D 1:, p,: 0f nu1fo!! Name of ihe i Hfoi 1 vn e ,_ .I :'~\ , __ J ,--,, L.i L_J Namu X-(\mniirnll< Inflows CUTOFF !JfVll}Ei? ur How dlvhh:i. Ginii:cs ,it,!: CUTOFF mnH1ivcr\¢d Enk /, TAiWt It? ltisi:s ;i Oh0rs100 Flow Cutoff flow valuu 051,,'ti fot n CUTOF.F diviJcr 1A8UlrtR irWUJ!S'ft Name N,mie n! Dhnsim1 C,ffY< uwd wi!h ;1 TWV!.AR di, fr, NH, 1 w curn:). i , ; __ / '_J , __ _j L_1 ,.--..., _) [_J i:11 J L !IAnx. fl!NCTlONAL , ('rn:ff. cNmnc the.st: 1nin11:teh:nt ro <l®snbh: p,m11n,;1m s an: hl:rnk. Methot! nf m·~er-m111-w sinragi: Ll·vtdm; ln tlli: fo11c1iont1! ''-_) f)_ j lnithii lkad }USS tllDmde/11 /ISSCcittteti or !he conduit, ffu cnndui!, culvert h:svu !i:;lcd in 'l ;:bk cf r APPENDIXF Drawdown Time Calculations l __ / L j L 1 l __ / '-' ', __ ) Bressi Ranch J-17169 January 20, 2016 Drawdown Time Calculations • DMA 1 Note: Following data were obtained from TAPE 21 as resulted from HEC-1 analyses. Each ordinate = 20 minutes Oout, max at WOv WSEL WOv 0.2109 (acre-feet) 0.391 @ (ft) 102.4 -(cfs) Ordinate 1st 2nd 3rd 4th 5th 6th 7th 0 4.436 2.566 1.484 1.052 0.77 0.564 200 0.208 0.206 0.204 0.202 0.2 0.199 400 0.19 0.188 0.186 0.184 0.183 0.181 600 0.172 0.17 0.169 0.167 0.165 0.164 800 0.156 0.154 0.153 0.151 0.15 0.148 1000 0.141 0 .. 14 0.138 0.137 0.136 0.134 1200 0.122 0.12 0.117 0.115 0.112 0.11 1400 0.098 0.096 0.094 0.092 0.09 0,088 1600 0.079 0.077 0.075 0.074 0.072 0.071 1800 0.063 0.062 0.06 0.059 0.058 0.057 2000 0.051 0.05 0.048 0.047 0.046 0:045 2200 0.041 0.04 0.039 0.038 0.037 0.036 2400 0.033 0.032 0.031 0.031 0.03 0.029 2600 0.026 0.026 0.025 0.024 0.024 0.023 2800 0.021 0.021 0.02 0.02 0.019 0.019 3000 0.017 0.016 0.016 0.016 O.Q15 0.015 3200 0.013 0.013 0.013 0.013 0.012 0.012 3400 0.011 0.011 0.01 0.01 0.01 0.01 3600 0.009 0.008 0.008 0.008 0.008 0.008 3800 0.007 0.007 0.007 0.007 0.006 0.006 4000 0.006 0.005 0.005 0.005 0.005 0.005 4200 0.004 0.004 0.004 0.004 0.004 0.004 4400 0.004 0.004 0.003 0.003 0.003 0.003 4600 0.003 0.003 0.003 0.003 0.003 0.003 4800 0.002 0.002 0.002 0.002 0.002 0.002 5000 0.002 0.002 0.002 0.002 0.002 0.002 5200 0.001 0.001 0.001 0.001 0.001 0.001 5400 0.001 0.001 0.001 0.001 0.001 0.001 5600 0.001 0.001 0.001 0.001 0.001 0.001 5800 0.001 0.001 0.001 0.001 0.001 0.001 6000 0.001 0.001 0.001 0.001 0.001 0.001 6200 0.000 0.000 0.000 0.000 0.000 0.000 Drawdown Time to Low Flow Orifice (hours): 54.7 (Measured to 00 u, = 0.0 cfs) 'DDT -fi,c lcJQv ;;;::,,. S'S-hr5 J t>1rr -&-H fV\ f~ ~ S-t hr ·s H:\ 171691 WaterResources\Hydromodification\Drawdown\ 17169 _Drawdown_ Time .xis 0.412 0.197 0.179 0.162 0.147 0.133 0.107 0.086 0.069 0.055 0.044 0.036 0.029 0.023 0.018 0.015 0.012 0.009 0.008 0.006 0.005 0.004 0.003 0.003 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.000 Qout, allow at HMPv 4.4355 (cfs) 8th 9th 10th 0.302 0.221 0.209 0.195 0.194 0.192 0.177 0.176 0.174 0.16 0.159 0.157 0.145 0.144 0.142 0.131 0.128 0.125 0.105 0.103 0.1 0.084 0.082 0.081 0.068 0.066 0.065 0.054 0.053 0.052 0.043 0.042 0.042 0.035 0.034 0.033 0.028 0.027 0.027 0.022 0.022 0.021 0.018 0.018 0.017 0.014 0.014 0.014 0.012 0.011 0.011 0.009 0.009 0.009 0.007 0.007 0.007 0.006 0.006 0.006 0.005 0.005 0.005 0.004 0.004 0.004 0.003 0.003 0.003 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 0.000 0.000 (OK) I Bressi Ranch J-17169 January 20, 2016 ', ! Drawdown Time Calculations -DMA 3 Note: Following data were obtained from TAPE 21 as resulted from HEC-1 analyses. Each ordinate = 20 minutes Oout, max at Oout, anow at WOv WSEL WOv 0.0635 HMPv 0.4229 (acre-feet) 0.030 @ (ft) 102.1 _.. (cfs) (cfs) Ordinate I 1st 2nd 3rd 4th 5th 6th 7th 8th 9th 10th 0 0.423 0.307 0.202 0.124 0.076 0.063 0.061 0.060 0.059 0.058 200 0.057 0.056 0.055 0.054 0.053 0.053 0.052 0.051 0.050 0.049 400 0.048 0.047 0.047 0.046 0.045 0:044 0.044 0.042 0.041 0.039 600 0.037 0.036 0.035 0.033 0.032 0.031 0.030 0.028 0.027 0.026 800 0.025 0.024 0.023 0.022 0.022 0.021 0.020 0.019 0.018 0.018 1000 0.017 0.016 0.016 0.015 0.014 0.014 0.013 0.013 0.012 0.012 1200 0,011 0.011 0.011 0.010 0.010 0.009 0.009 0.009 0.008 0.008 1400 0.008 0.007 0.007 0.007 0.007 0.006 0.006 0.006 0.006 0.005 '-,) 1600 0.005 0.005 0.005 0.005 0.004 0.004 0.004 0.004 0.004 0.004 1800 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.003 0.002 2000 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 0.002 2200 0.002 0.002 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 2400 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 L-! 2600 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.001 0.000 2800 0.000 1--1 /_J I ) Drawdown Time to Low Flow Orifice (hours): 19.3 (Measured to 0 0u, = 0.0 cfs) (OK) H :\ 17169\WaterResources\Hydromodification\Drawdown\ 17169 _Drawdown_ Time.xis APPENDIXG Potential Critical Coarse Sediment Yield Exhibit L ) This exhibit reflects "potential" critical coarse sediment yield areas (PCCSY As) identified within the project site based on regional-level mapping prepared for the "San Diego County Regional Watershed Management Area Analysis" (Regional WMAA) dated April 27, 2015, which includes "2015 Regional Potential Critical Coarse Sediment Yield Areas Map" dated September 8, 2014. When PCCSY As are identified based on the regional-level mapping, the Model BMP Design Manual dated June 2015 allows for project-level evaluation to determine (I) whether geomorphic landscape units (GLUs) that the Regional WMAA classified as PCCSY As actually are present at the site [a GLU is a unique combination of slope, geology, and land use], (2) whether downstream storm water conveyance systems would be sensitive to reduction in coarse sediment load, and/or (3) whether coarse sediment originating from the site is critical to the downstream system, where "critical" means the · 'sediment produced is a source of bed material to the receiving stream. Mitigation measures are only required if it is determined that coarse sediment originating from the project site is critical to stability of downstream systems conveying runoff from the project site. As shown, the PCCSY As are limited to a few locations along the southerly edge. However, it is important to recognize that this project site has already been rough graded • 1including installation of four (4) sediment basins. The general slope of the site is at approximately 2.5% from NE to SW, which is significantly less than the 10% minimum slope typically associated with GLUs that can be categorized as PCCSYAs. Due to the previous mass-grading of the site, the less than 10% slope of the development pad, and the existence of sediment basins that prevent the discharge of sediment in the existing condition, the PCCSY As should not be considered critical (i.e. -since they are not delivered to the downstream system, even if they were determined to meet the GLU classifications for PCCSY As). Final verification of the actual GLUs using project-based topographic information for slopes, soil types, and ground cover can also be included in the Final PDP SWQMP that will be prepared with the final design for the project. [:~] Property --Streams Drain Structure Storm Drain PCCSYAreas No ·---· Yes FEMANFHL 100-YR Floodway 100-YR Floodplain RICK ENGINEERING COMPANY 0 Scale in Feet 800 1.600 0 North Date of Exhibit: 1/20/2016 SANGSI PC CSY: 03.2015 FE/v\A NFHL:03/28/2014 Eagle Aerial Image: 04/2013 Bressi Ranch PCCSY Areas JN: 17619 Appendix H Feasibility Worksheets for Infiltration and Harvest & Use --1 l~j L -j ' __ I Appendix B: Storm Water Control Hyd:miogk Cakuladons and Sizing Methods Worksheet B.2-1. DCV percentile 24-hr storm depth from Figure B.1-1 to BMP 's) weighted runoff and B.2.1) ( estimate using Appendix B.1.1 Street trees volume reduction Rain barrels volume reduction Calculate DCV = -RCV inches acres unitless cubic-feet June 2015 1 _ _j ,, ,---, [ ___ / ,--, ..,,,.,,,.,,1,.,.. B: Storm Water Pollutant Control Hydrologic Cakulatio:m, and Sizing Methods B.4.1 Simple Method 1. 2. 3. Compute DCV using Worksheet B.4-1 Estimate infiltration rate using Worksheet D.5-l Design to ensure that the DCV is fully retained (i.e., no surface discharge during the design event) and the stored depth draws down in no longer than 36 hours. Worksheet B.4-1: Simple Sizing Method for fofili:ration BMPs infiltration rate l\'Vorksheet D.5-1\ veraoe effective de Jth in the BMP foot Jtint iDCV / All;,w) T= Provide alternative calculation drawdown time, if needed. • Drawdown time must be less than 36 hours. This criterion was set to achieve average annual capture of 80% to account for back to storms (See rationale in Section B.4.3). In order to use a different drawdown time, BMPs should be sized using the percent capture method (Section B.4.2). * The average effective depth calculation should account for any aggregate/media in the BJvIP. For example, 4 feet of stone at a porosity of 0.4 would equate to 1.6 feet of effective depth. * This method may overestimate drnwdown time for BlvfPs that drain through both the bottom and walls of the system. Bl\1P specific calculations of drawdown time may be provided that account for BJv1P,specific geometry. B-19 June 2015 ,--~ I ,_) ___ } c_J Appendix D: Approved Infiltration Rate Assessment Methods Worksheet D.5-1: Factor of Safety and Design fofiltrntfon Rate Worksheet Factor Catego.ry Factor Description l3 Suitability Assessment Design Soil assessment methods Predominant soil texture Site soil variability Depth to groundwater / impervious Redundancy/ resiliency Compaction during construction Safety Factor, Sn ::::: :Ep Combined Safety Factor, S«,1a1= S,.1 x Sn Observed Infiltration Rate, inch/hr, K,1,,rmd (corrected for test-specific bias) Design Infiltration Rate, in/hr, K,ksign = K,b,md / S,ornl Data des,:ribe infiltration test and provide reference to test forms: D-19 June 2015 'L ___ j ' I u , _ _,_J _J ,_,_J ', _) __ j Appendix B: Storm Water Pollutant Control ,Hydrologic Calcufati011s and Sizing Methods The purpose of this section is to guidance for evaluating feasibility of harvest and use calculating harvested water demand and sizing harvest :md use BTvfPs. B.3.1 Harvest and Use Harvest and use feasibility should be evaluated at the scale of the entire project, and not limited to a single DrviA. For the purpose of initial feasibility it is assumed that harvested water collected from one DIViA could be used \Vithin another. Types of non--potable water demand that may apply ·within a project include: ® Toilet and urinal flushing ® Irrigation • V ehide washing ® Evaporative cooling ® Dilution water for recvded water svstems , ' ® Industrial processes • Other non-potable uses \vorksheet B.3-1 provides a screening process for determining the preliminary feasibility for harvest and use Bl\1Ps. This ,vorksheet should be completed for the overal.1 project. B-11 June 2015 . .I LJ '. __ :, ._.___,I -_ _J Appendix B: Storm Water Pollutant Control liydrologic Calculations and Sizing Methods Worksheet B.3-1. Harvest and Use FeasibiHty Screening 1. Is there a demand for harvested water (check all that apply) at the project site that is reliably present during the wet season? IS:a"Toilet and urinal flushing Gl'Landscape irrigation D 2. If there is a demand; estimate the anticipated average wet season demand over a period of 36 hours. Guidance for planning levd demand calculations for toilet/urinal flushing and landscape irrigation is provided in Section B.3.2. [Provide a summary calculations here] 3. Calculate the DCV using worksheet B-2. 1. [Provide a results here] ·c::, V :::c-3 s; 3t.; 3 (Jt,. • 3a. Is the 36-hour demand greater than ot ec.1ual to the DCV? Yes I J} 3b. Is the 36-hour demand greater than 0.25DCV but less than the full Yes I {I. Is the 36-hour ----------+-----------------·!----------··-··-······· Harvest and use appears to be feasible. Conduct more detailed evaluation and sizing calculations to confirm that DCV can be used at an adequate rate to meet drn.wdown criteria. Harvest and use may be feasible. Conduct more detailed evaluation and sizing calculations to determine feasibility. Harvest and use may only be able to be used for a portion of the site, or (optionally) the storage may need to be upsized to meet long term , capture targets while draining in i I longer than 36 hours. Harvest and use is considered to be infeasible. June 2015 \_ j -_i Appendix B: Storm Water Pollutant Control Hydrofogic Cakufations and Sizing Methods Worksheet B.2-1. DCV ! __ ) , _ _J Appendix B.1.l C= unitlcss barrels volume reduction 3630 x C x d x N -TCV -RCV cubic-feet :_} ' ' ' __J , __ J ,J June 2015 TM ENGINEERING COMPANY ', __ ) ,_J -,, --J J 5620 Friars Road San Diego, CA 92110-2596 Td: (619) 291-0707 fax: (619) 2914165 D Date No. Done By c::hecked '_ ) l __ J 1, _J ·~--J iJ ,-, 1 _ __J ,, , _j ~-J ,~1 ,---, : _j rM 5620 Friars Road San Diego, CA 92110-2596 Tel: (619) 291-0707 Fax, (619) 291-4165 / I l J1 /3 Daw Job No. Done Checked L .. J LJ l_J L.J ik;_J APPENDIX I Summary of Anticipated Refinement in Final Engineering for 2013 MS4 Permit, 2015 Model BMP Design Manual, and 2016 Local BMP Design Manual ~-_j c-1 The initial versions of this Preliminary Storm Water Management Plan were prepared based on our understanding of the 2013 MS4 permit as of November 2014 and March 2015, prior to the Model BMP Design Manual being finalized in June 2015. Since the Preliminary SWMP was close to approval, it was agreed the report format would remain as a Preliminary SWMP and should incorporate the additional BMP design criteria identified in the Model BMP Design Manual; while recognizing that a Final SWMP (or Final PDP SWQMP) would ultimately be prepared during final engineering to reflect the 2016 Local BMP Design Manual for the City of Carlsbad. The following is a bulleted summary of the refined criteria, impacts to the project design approach, and information specific to the TC-BMPs (aka pollutant control BMPs) and HMP that will be further refined during the final engineering stage of design and approval: • Use of Permeable Pavers: o In earlier versions of this report, Permeable Pavers were proposed as a site design feature and as a way of reducing the runoff factor. However, with the introduction of the 2015 Model BMP Design Manual, it has been confirmed that only permeable pavement without an underdrain AND liner can be used as a site design feature to reduce the runoff factor (unless the underdrain is elevated significantly). Due to the poor soil conditions on site, the geotechnical engineer for the project has suggested the installation of an underdrain and potential liner for the proposed permeable pavers. Due to this, since there is minimal benefit given for utilizing permeable pavers, the limits have been reduced within the commercial portion of the site to parking stalls only, and in locations not immediately adjacent to proposed buildings. The updated water quality volume calculations reflect this change and give no credit towards reducing the runoff factors. The remaining permeable pavers will serve to disconnect directly connected impervious areas and provide some initial infiltration and pollutant removal. Final configuration of the permeable paver locations will be identified during final engineering. • Cistern to Biofiltration: o A "Cistern to Biofiltration" concept has been utilized for this project (i.e. - Underground Detention Vault dripping out to Biofiltration Planters). In addition to the release of the Model BMP Design Manual in June 2015, draft criteria is under development by the Copermittees to specifically address the concept of Cistern to Biofiltraiton, which will allow the biofiltration footprint to be less than 3%. The draft criteria was reviewed against the proposed approach within this Preliminary SWMP for consistency and the final configuration of the vault sizes and outlet works will be updated in final engineering to reflect this criteria. • Hydromodification Management: o The 2013 MS4 Permit dictates that HMP analyses compare post-project conditions to pre-development conditions. The SWMM analysis prepared for this project was completed on this assumption. Minor updates based on exact L_ _ _J impervious and pervious areas and parameters identified in the 2016 Local BMP Design Manual will also be incorporated during final engineering. COMPACT DISC (CD): Electronic Files for Storm Water Management Model (SWMM) L _ _J L. J k .... J b_J L_ __ J L.,J ik. .. J L__j l.c.~I MAP POCKET 1 HMP Pre-Development Exhibit for Bressi Ranch (Lots 29 thru 32) 60-30 60 -180 120_ - 1"= 60' GRAPHIC SCALE . • . i S620 FRIARS~~~ O l;;;I SAN DIEGO, I eedag.com IM!~~~C~oiM~P~A~N~Y ge-San Luis Obispo '~E~N~G~I;N~E:ER:I:N::G::::::::__!R~!v~e~~,d~e~-~o~,aa"'°-~~ . J San Diego " - ,..,_, ,.,, """ 17"3AC ,.., /'''\'-::11,:·~':J.j '· f_-:::ti::, I,/'\~~~ ·--,,~.,.._, .. ,, X ..rJJl ,.,, X"" £; ' ' ff ' '''" ,..,,, )( 4197. .FOR NOT CONSTRUCTION )( .f/!,ljj X '""' ""' /",,.,,.,,, ,,:,,,,~-.., EXHIBIT FOR STORM WATER i I 'if , I ' , ,j /1:· i i I ii i ii I': I ; I i I I I ) I t I Ji :1 .) i I I r , :\ , f ii I '* i!~if\i~ ' , , 1-r I i I , • . ! I ; ! ;1 '. ! I I !Ii ! : 'i ' ! ' /--------------------- ! --~-···-·-··-'·"~-..... _ -----. II /-;:---------- ' ! ,-·-··--·-· ---..• ---. / ,' ····--.'.,. _____ ------' ' ' ' ' MANAGEMENT PLAN ONLY 'f;' i . COLT PL . ·. . p l VICINITY MA NO SCALE ' ····--"~·-··· i . . '. ' BMP /IMP LE~EN D PRE-DEVELOPMENT DMA BOUNDARY j ;1 " ....... ,'-' --~ •i .- -;-;, AC.) DMA AREA (0.2 AC. . J-17169 POI NT OF CONCERN HMP ;, ,. ' HMP EXHIBi~g~ . BRESSIHRU 32) . (LOTSEV2:L~PMENT) (PRE-D ber 24, 2014 Date: Novem h 25 2015 Revised: Marc 2 o' 2016 . ed· January ' Revis · -- f'I MAPPOCKET2 r··,, DMA/IMP Exhibit for LJ Bressi Ranch r,--..-1 for I LJ Water Quality & HMP L_I (Lots 29 thru 32) r-"""l LJ LJ bc.J I 60 30 60 --GRAPHIC SCALE ·---. .. - X-"""'7 X 180 120_ ; q I!' ! -,::::::.".; i ' ' -:C:::~ I ~1 -1 : =- -=·::5 ~::.:=:- _.,..::::J ::.~ ~' ;, ~C\lillLJ 'rF~ I: =--- - \ ', 1 ,,,..A I : '<.' I 1 ,: -i ;-}'~ 1 I '-,y ' I ' -. -·-~ l .... '( -; ,;_,Ji ,,:~3 .. -.. _7 : .. ._.,,.;::_) A ----:.--.... B ' -,c:-·-' '"1f··;:-:--·~.,"' l \ . i < i : ; ~~r·"r1 '-D~M"A-·2?1 \ ' 'S:J -...,b. C • \ ~' ' i ' j j ' ' ' ' ' ,,,,, ; I if / I ' I !I ; ' ;: i I ., /i,, '!, !!;. 1 ii ' " l :' µf[j' 'I I: " I,. , , , ', '· ',' , .. · -, '.'~.) : it.i: "'.a! I, / 1 i r;:) -~ ) '.\ 1 ' <,~ \ '~ // . \ ' . ' .. i i ! ··------ , .t,)' ,' ,' . 5620FRIARS~~f O ---------:~~~~R (C:CONSTRUCT I ON .... ~em=, ,,. .... ,,.... NOT FOR f Ii! ll cc: !>\I ;k;: ~;:•.., . ~·e.,;fie;ld~-;s,;c.~a~;~:~~:t"~:~;o;en~;,:, T~uc;,o~n'.._ _____ _ ' -~ -COMPANY e _ San Lu;, Ob,spo ~ I ENGINEERING e;ve.,;de -Ocang • . 0 If. San D1eg g ,::" ~ "·,!'-~-~~~~~ MMAANN1AGEMENT STORM WATER EXHIBIT FOR ' / ' ' ' ' PLAN ONLY I .. "" -,'' ~ ·-.I ;.,,.~ ,·,·,~:_,~(~ :.:t.:,·,.: -------,_ ----- ~ -·' \ "'\;~·\ r"'.,i ,.,i;.. . , i INNOVATION WY LOKER AVE W PALOMAR AIRPORT RO ~ ~-\~~SITE COLT PL VICINITY MAP NO SCALE ·--·-=--··-·-_:_:______ ----==- NOTES DISCUSSED IN MORE ONSTRUCTJON BMPsE~R~ANAGEMENT PLAN. THESE POST-CN THIS STORM WAT BRESSI '-°'" " " '" ' " °'" '"' srncv s ";,, , '" ORT TITLED NOVEMBER ' JNAGE 2. REFER ~gT:E~9 THRU 32~E~~i~~ COMPANY 1~gRl~~~RMATION. """ " " '"'' """"' s " PREPARED B~ NUMBERS AND ADD O BIOFILTRATION AREAS, NOD A " c J STERN T ND 3 WILL UTLIZETREATMENT AND DMAs 1,2, A WATER QUALITY '· .eeao,c, '::,.0 , '"''"'"'"'· "'" '"" ,ma HYDROMODFI . BIOFILTRATJON AGEMENT UTILIZE TWO (2) OMODIFACTION MAN(\ E D-25Sl 4 . DMA iT~ 1 ~~EATMENT ANDR~~~~sE CURB ou;~Ei~To EACH BMP. QUAL G CURB CUTS, 0 DIVERT RUNO UTILIZJ~HALLOW INLETS T RKING AREAS AND/OR VERS WITHIN PA PROJECT PERMEABLE PA RTION OF THE EXPECTED 5. THE u~~To~HE COMMERCIA~E:~GN BMPS AN~E~~~\NG SOILS) THROU AS LID SITE TO POOR UN ARE MEANT SUBDRAJNS (DUE TO INCLUDEEABLE LINERS. AND IMPERM BMP /IMP LEGEND °'" ,o"""" PRE~DEVELOPMENT (0.2 AC. ) !OMA 4 ! DMA AREA ~ --~ PO INT OF CONCERN HMP DMA SUB-BOUNDARY LOCATION CISTERN/VAULT OF PROPOSED LOCATION OF PROPOSED DMA BOUNDARY DMA NUMBER FACILITY BIORETENTJON . VER AREA .. ,., ,-,~ """'"" FOR ~"i;,t: DMA/IM:Ri1~/BiNCH THRU 32) (LOTS 29 & HMP) CT FORWQ (POST-PROJE.. 2014 her 24, Date: Novem h 25 2015 J-17169 . d· Marc ' 16 Re~1es~·J ·anuary 20, 20 Revis · ~~