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Home My WebLink AboutSDP 15-26; LEGOLAND HOTEL CALIFORNIA II AKA LLC H20#2; STORM WATER QUALITY MANAGEMENT PLAN FOR LEGOLAND REGIONAL WATER QUALITY; 2018-03-05CITY OF CARLSBAD PRIORITY DEVELOPMENT PROJECT (PDP) COMPLEMENTARY STORM WATER QUALITY MANAGEMENT PLAN (SWQMP) FOR LEGOLAND REGIONAL WATER QUALITY/ HYDROMODIFICATION BMP SOP 15-26/CDP 15-50 DWG: 498-2C I GRD2017-0025 ENGINEER OF WORK: LUIS PARRA, PhD, CPSWQ, ToR, D.WRE RCE 66377 -06/30/2018 PREPARED FOR: LEGOLAND 1 LEGOLAND Drive Carlsbad, CA, 92008 (877) 396-5346 PREPARED BY: R·E·C Consultants, Inc. 2442 Second Avenue San Diego, Ca, 92101 619-232-9210 DATE: 5/18/2017 (Revised June 22, 2017; September 29, 2017; December 7, 2017; March 5, 2018) Addendum No. 3: LEGOLAND PARKING STRUCTURE #2 I I I I I I I I i 'l I TABLE OF CONTENTS Certification Page Project Vicinity Map Site Information FORM E-36 Standard Project Requirement Checklist Summary of PDP Structural BMPs Attachment 1: Backup for PDP Pollutant Control BMPs Attachment 1 a: OMA Exhibit Attachment 1 b: Tabular Summary of DMAs and Design Capture Volume Calculations Attachment 1c: Harvest and Use Feasibility Screening (when applicable) Attachment 1d: Categorization of Infiltration Feasibility Condition (when applicable) Attachment 1 e: Pollutant Control BMP Design Worksheets / Calculations Attachment 2: Backup for PDP Hydromodification Control Measures Attachment 2a: Hydromodification Management Exhibit Attachment 2b: Management of Critical Coarse Sediment Yield Areas Attachment 2c: Geomorphic Assessment of Receiving Channels Attachment 2d: Flow Control Facility Design Attachment 3: Structural BMP Maintenance Thresholds and Actions Attachment 4: Single Sheet BMP (SSBMP) Exhibit CERTIFICATION PAGE Project Name: LEGOLAND , ; i ~ ';~~ \ , I Project ID: SOP 15-26iCDP 15i50-COMPLEMENTARY SWQMP FOR REGIONAL BMPs I hereby declare that I am the Engineer in Responsible Charge of design of storm water BMPs for this project, and that I have exercised responsible charge over the design of the project as defined in Section 6703 of the Business and Professions Code, and that the design is consistent with the requirements of the BMP Design Manual, which is based on the requirements of SDRWQCB Order No. R9-2013-0001 (MS4 Permit) or the current Order. I have read and understand that the City Engineer has adopted minimum requirements for managing urban runoff, including storm water, from land development activities, as described in the BMP Design Manual. I certify that this SWQMP has been completed to the best of my ability and accurately reflects the project being proposed and the applicable source control and site design BMPs proposed to minimize the potentially negative impacts of this project's land development activities on water quality. I understand and acknowledge that the plan check review of this SWQMP by the City Engineer is confined to a review and does not relieve me, as the Engineer in Responsible Charge of design of storm water BMPs for this project, of my responsibilities for pro·ect design. R.C.E. 66377 06/30/2018 PE Number Expiration Date Luis Parra Print Name REC Consultants, Inc. Company 03/05/2018 Date :1 I I I I I ii , :I· :I: ,,~ 'I I ., I, I I I ~,, I PROJECT VICINITY MAP City of Carlsbad Palomar Airport Rd VICINITY MAP NOTTO SCALE r-------------------li {'cicyof Carlsbad STORM WATER STANDARDS INTRODUCTION/PURPOSE FOR THIS COMPLEMENTARY SWQMP INTRODUCTION / PURPOSE Development Services Land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov This SWOMP Report is written with the intent to provide a background that explains how the existing detention facilities located at the south of the LEGOLAND property can be updated and transformed to perform water quality, hydromodification control and flood control functions for a portion of the LEGOLAND property. Flood control (100-year storm routing) will be addressed in detail in the Drainage Report while water quality and hydromodification control is the fundamental objective of this complementary SWOMP. Calculations will be based on the current Carlsbad BMP Manual and/or continuous simulation according to the EPA SWMM Model. Water Quality Objective In regards to water quality, the existing two (2) detention facilities can be transformed to act as a biofiltration facilities, with enough capacity to treat a large area of the LEGOLAND property. This treatment capacity will act as a "water quality bank account" meaning that future re-development projects in the LEGOLAND property (new hotels, modifications to the parking lots, new rides, etc) can rely on the treatment capacity of the facilities until the water quality treatment capacity is used (the "water quality bank account" created by the regional biofiltration basins is exhausted). Therefore, the water quality treatment capacity of the biofiltration facilities will allow many projects to satisfy water quality requirements until there is no excess of water quality capacity left. The transformation of the existing detention basins will occur basically in two (2) forms: (a) the bottom of the facilities will be improved and will become a vegetated amended soil with gravel and filter layers, and French drain for drainage purposes, and (b) the surface of the facility up to certain depth will drain only via infiltration, insuring enough volume for water quality treatment purposes. Hydromodification Objective Similarly than in the water quality case, the _ existing two (2) detention facilities can be transformed to act as hydromodification facilities with enough capacity to satisfy hydromodification requirements (Flow Duration Curve compliance) of an even larger area of the LEGOLAND property. This hydromodification capacity will also act as a "hydromodification bank account" so that future re-development projects in the LEGOLAND property can rely on the hydromodification capacity of the biofiltration facilities until the hydromodification treatment capacity is used (the "hydromodification bank account" created by the regional biofiltration basins is exhausted). Therefore, the hydromodification treatment capacity of the biofiltration facilities will allow many projects to satisfy hydromodification requirements until there is no excess of hydromodification capacity left. Hydromodification capacity is larger than water quality capacity due to the attenuating effect of the receiving point of compliance downstream: the receiving creek is a low susceptibility creek, and therefore the range of analysis is less stringent than in normal conditions. The transformation of the detention facilities into . hydromodification facilities will occur basically by changing the outlet structure of the facilities so that it can control peak flows from 50% of the continuous hourly 02 value to 100% of the continuous hourly 010 value. Determination of Water Quality Area For the purpose of area to be treated (in terms of water quality) by the two (2) regional biofiltration systems in LEGOLAND a detailed calculation included in the BMP Design section shows that an equivalent area of 51.612 acres can be treated. The Equivalent area (defined as Aeq = A • C) is the concept used in this SWOMP because it accounts for the combination of pervious (C = 0.10) and impervious areas (C = 0.90) plus areas not draining to the stormwater system (for example, ponds, C = O). For example, an area of 10 acres, 100% impervious has an equivalent area of 0.9·10 = 9 acres, while a larger 15 acre area which is 40% pervious, 40% impervious and 20% ponds (C = 0.4·0.9 + 0.4·0.1 + 0.2·0 = 0.4) has a smaller equivalent area of 15·0.4 = 6 acres. The use of the equivalent area definition allows for a more accurate accountability of the "water quality bank account" and "hydromodification bank account" represented by the regional biofiltration systems, as it takes into account pervious and impervious contributing area. • Determination of Hydromodification Area For the purpose of area to be treated (in terms of hydromodification) by the two (2) regional biofiltration systems in LEGOLAND a SWMM continuous simulation model included as a separate report proves that the runoff of a 78.617 acres I I I I I I I I I I I I. I _, I I I I I I equivalent area can be discharged after the biofiltrations in an equivalent manner than pre-development conditions, so that the hydraulic response of such area in the range of analysis satisfies the requirements imposed by the Flow Duration Curve comparison between pre and post-development conditions. Projects Covered by this Study and Remaining Area Left for Future Projects Attached in this section, Table A shows the calculation of the projects covered by this complementary SWQMP. Also, the remaining equivalent area still available for Water Quality and Hydromodification Compliance is included after Table A. TABLE A: Projects Covered by this Complementary SWQMP PROJECT Project ID IMPERV PERV Never Out TOTAL131 C Eq. Area (or Permit#) (acres) (acres) (acres) (to BMP, ac) Water Slide SDP 16-25 0.305 0.255 0.097 0.560 0.536 Parking Modif. 0.140 0 0 0.140 0.900 Phase II (ll PD 16-18 LLCH20 Hotel !2l SDP 15-26 5.237 1.725 0.138 6.962 0.702 Dark Ride SDP 16-24 0.555 0.345 0 0.900 0.593 TOTAL N/A 6.237 2.325 0.235 8.562 0.683 Notes: (1): the following was assumed: Area modified is the only area accounted for, and is 100% impervious. (2): Certain assumptions were made because pre-dev. areas" post-dev. areas in DCI report. Total area= existing calculated area. Total post-development area: assumed correct. Total area never draining out: pool area. Impervious area: Total -pervious, pool. (3): Total of impervious+ pervious areas (contributing to BMP), do not include areas never draining out (pool, for example). Equivalent Area remaining after the four (4) current projects mentioned in Table A 0.300 0.126 4.886 0.534 5.846 Water Quality: 51.612 acres -5.846 acres: 45.766 acres of Area Equivalent remains for WQ Compliance of Future LEGOLAND Re-development Projects. Hydromodification: 78.617 acres -5.846 acres: 72.771 acres of Area Equivalent remains for Hydromodification Compliance. This area takes care of the entire LEGOLAND property area, including future LEGOLAND Re-development Projects. SITE INFORMATION CHECKLIST (MODIFIED) , Project Summary Information Project Name LEGOLAND Project ID 5DP 15-26/CDP 15-50 Project Address 1 LEGOLAND Dr, Carlsbad, CA 92008 Assessor's Parcel Number(s) (APN(s)) 211-109-09 Project Watershed (Hydrologic Unit) Carlsbad 904 Parcel Area 128.5 Acres <5,597,460 Sauare Feet) Impervious Area to be treated by Regional Biofiltration Facility<a. b)_ Impervious areas from: 1) Current re-development projects to be treated 5.846 Acres (254,652 Square Feet) (Hotel2, JD18, WP17, Parking lot modification) 2) Future Redevelopment projects to be treated 45.766 Acres (1,993,567 Square Feet) Existing Pervious Area to be treated by 2.33 Acres (101,277 Square Feet) Regional BMPs (Current value, see list of projects in Table A, previous page) Area to be disturbed by the project 2.23 Acres (97,342 tt2) (Regional BMPs) {Proiect Area of Regional BMPs) Notes: a) The project does not propose any impervious area; rather, it proposes the modification of detention basins to convert them into regional BMPs for future LEGOLAND expansion projects. b) The Regional Biofiltration facility has the capacity to satisfy the entire LEGOLAND's hydromodification requirements -about 78.6 acres of impervious area. I I I I I f I I ~,. ' . I I I I I I 1. I I I· I· , 1. ·.1·. ii I I 1: I II I :1 !1 I; I I; . • •. • .. • • ... Oescrii>tion :Of Existing Site Condition· and Drainage Patterns Current Status of the Site (select all that apply): 181 Existing development • D Previously graded but not built out □ Agricultural or other non-impervious use □ Vacant, undeveloped/natural Description/ Additional Information: The project site is currently developed. It is composed of parking lots, walkways, amusement rides, landscape areas and two regional basins on the south side of the project. Existing Land Cover Includes (select all that apply): 181 Vegetative Cover D Non-Vegetated Pervious Areas 181 Impervious Areas Description / Additional Information: The site is currently developed with pervious and impervious areas. Underlying Soil belongs to Hydrologic Soil Group (select all that apply (BMPs)): 181 NRCS Type A 181 NRCS Type B □ NRCS Type C 181 NRCS Type D Approximate Depth to Groundwater (GW): □ GW Depth < 5 feet 1815 feet< GW Depth< 10 feet (expected value for Regional BMPs) D 10 feet < GW Depth < 20 feet 0 GW Depth > 20 feet . Existing Natural Hydrologic Features (select all that apply): D Watercourses D Seeps □Springs □Wetlands 181 None Description/ Additional Information: Description of Existing Site Topography and Drainage [How is storm water runoff conveyed from the site? At a minimum, this description should answer (1) whether existing drainage conveyance is natural or urban; (2) describe existing constructed storm water conveyance systems, if applicable; and (3) is runoff from offsite conveyed through the site? if so, describe]: Presently, the LEGOLAND project site is developed with both impervious and pervious surfaces, and the existing drainage is urban. As it is an existing developed site, most of the project area does not require compliance with new regulations: only areas to be re-developed (such as parking lot modifications, new rides, etc) will need to satisfy water quality and hydromodification compliance. Many project areas within the park that have been recently re- developed are currently draining to individual water treatment systems, and they will continue to do so in post conditions. Some of the storm water conveyance and treatment systems are underground treatment system, conveyance underground pipe systems and filter systems. All of the runoff for LEGOLAND (existing areas without treatment devices and recently re-developed areas with biofiltration systems or underground systems) eventually is conveyed through the site and ends up discharging into two (2) basins on the south side. This SWQMP evaluates the capacity of the existing detention basins, and converts it into a combined biofiltration, hydromodification and detention facility to compensate for water quality and hydromodification requirements of four (4) recently approved projects: the Water Slide, the Parking Modification Phase 11, the LLCH20 Hotel, and the Dark Ride. The regional biofiltration systems proposed here not only have enough capacity for the four (4) projects mentioned, but also have remaining capacity for extra water quality and hydromodification mitigation. In other words, for future projects, the biofiltration systems will have additional capacity for both Water Quality and Hydromodification (hydromodification additional capacity being larger than water quality additional capacity). In regards to water quality, calculations will show that the system proposed (2 detention basins converted into biofiltration basins) has enough capacity for the treatment of 51.612 acres of equivalent area, and the four (4) projects mentioned will use 5.846 acres, leaving a water quality remaining equivalent area of 45.766 acres for future projects. In regards to hydromodification, continuous simulation calculations will show that the system proposed has enough capacity for the treatment of 78.617 acres of equivalent area, and the four (4) projects mentioned will use 5.846 acres, leaving a hydromodification remaining capacity of 72.771 acres of equivalent area ~or hydromodification compliance of future projects; I ·I -1 I I .,· ;I I ,~ I I I .1 I I I I· I I ;I I' ' ' I I I :1 I I I I ,,- I_ I I I Description of Proposed Site Development and Drainage Patterns Project Description / Proposed Land Use and/or Activities: LEGOLAND is an existing developed theme park. The project proposed requires the upgrade of two (2) detention basins to serve as water quality and hydromodification features (in addition to its current flood control function that will be preserved) for future development to occur in LEGOLAND. Currently, the basins are justified as a water quality and hydromodification treatment alternative for four (4) projects: the Water Slide, the Parking Lot Phase II, the LLCH20 Hotel, and the Dark Ride. The two basins have WQ capacity to treat future re-development up to an additional 45.766 acres of equivalent area, and have hydromodification capacity up to 72.771 acres of equivalent area. Any redevelopment at the LEGOLAND property below the lower WQ threshold will be exempt from SWQMP as the runoff will drain to one of these two basins. Re- development above the lower threshold but below the higher threshold will require a SWQMP for WQ only, while re-development exceeding the higher threshold will require a complete SWQMP (WQ + hydromodification). LisUdescribe proposed impervious features of the project (e.g., buildings, roadways, parking lots, courtyards, athletic courts, other impervious features): The project itself does not include any impervious feature, but will serve for treatment of re-development areas in the LEGOLAND property, including parking lots, sidewalks, roofs, roads, etc, as long as those areas do not exceed the thresholds explained in previous section of this document. Basically, and because of this project, LEGOLAND can choose to update any area of their property up to 45.7668 acres of equivalent area for WQ purposes, and up to 72.771 acres of equivalent area for hydromodification purposes, in addition to the areas shown in Table A. LisUdescribe proposed pervious features of the project (e.g., landscape areas): The proposed pervious features will consist of any landscape areas and the two basins at the south side that will be regraded. Additionally, in the future LEGOLAND can choose to update any area of the project and add pervious areas as a replacement of existing impervious areas. Does the project include grading and changes to site topography? ~Yes □No Description/ Additional Information: As the site is currently developed, the grading changes will be minimal. One area where the grading changes will be more significant will be in south border of the project as the two basins will be regraded to serve better as regional alternative compliance basins. Does the project include changes to site drainage (e.g., installation of new storm water conveyance systems)? [8J Yes □ No Description/ Additional Information: The changes to the site drainage will be in the outlet structures that will be located in the two basins at the south edge of the project. The changes will generate hydromodification compliant discharges for the entire site, so they can be considered as positive changes. Additionally, in the future when LEGOLAND updates a ride or makes any changes, there will be drainage changes. However, all of the runoff will still drain to one of the two regional biofiltration basins. See Attachment 5 for detailed calculations. I I ,I ,I I, I I I I I ' ' I I I I ·1 -_, .I (j ), I II I I I I' I I .1 I I· I ,,- I_ ,J I I Identify whether any of the following features, activities, and/or pollutant source areas will be present (select all that apply): (ii"! reference to the regional biofiltration basins) 181 On-site storm drain inlets (or outlets) D Interior floor drains and elevator shaft sump pumps □ Interior parking garages D Need for future indoor & structural pest control 181 Landscape/Outdoor Pesticide Use D Pools, spas, ponds, decorative fountains, and other water features □Foodservice D Refuse areas D Industrial processes. □ Outdoor storage of equipment or materials D Vehicle and Equipment Cleaning □ Vehicle/Equipment Repair and Maintenance D Fuel Dispensing Areas □ Loading Docks □ Fire Sprinkler Test Water D Miscellaneous Drain or Wash Water □ Plazas, sidewalks, and parking lots Identification of Receiving Water Pollutants of Concern Describe path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable): Stormwater runoff from LEGOLAND will be discharged from one of two regional BMP basins and drain into Encinas Creek Basin. Once in Encinas Creek it will travel westerly where it eventually makes it into the Pacific Oceans Shoreline. List any 303(d) impaired water bodies within the path of storm water from the project site to the Pacific Ocean (or bay, lagoon, lake or reservoir, as applicable), identify the pollutant(s)/stressor(s) causing impairment, and identify any TMDLs for the impaired water bodies: 303(d) Impaired Water Body Pollutant(s)/Stressor(s) TMDLs Encinas Creek Basin (904.40) Indicator Bacteria Pacific Ocean Shoreline (904.10) Indicator Bacteria I • Identification of Project Site Pollutants Identify pollutants anticipated from the project site based on all proposed use(s) of the site (see BMP Design Manual Appendix B.6): (taken from SWQMP LLC H20) Also a Receiving Not Applicable to Anticipated from the Water Pollutant of Pollutant the Project Site Project Site Concern Sediment □ ~ □ Nutrients □ ~ □ Heavy Metals ~ □ □ Organic Compounds ~ □ □ Trash & Debris □ ~ □ Oxygen Demanding ~ □ □ Substances Oil & Grease □ ~ □ Bacteria & Viruses □ ~ ~ Pesticides ~ □ □ I I I I II .1 _I I I I I' I I I ,~ I :1: I I I I -, I I ,I I I I I I ,I _I I 1 Hydromodification Management Requirements Do hydromodification management requirements apply (see Section 1.6 of the BMP Design Manual)? [8J Yes, hydromodification management flow control structural BMPs required. □ No, the project will discharge runoff directly to existing underground storm drains discharging directly to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. □ No, the project will discharge runoff directly to conveyance channels whose bed and bank are concrete-lined all the way from the point of discharge to water storage reservoirs, lakes, enclosed embayments, or the Pacific Ocean. □ No, the project will discharge runoff directly to an area identified as appropriate for an exemption by the WMAA for the watershed in which the project resides. Description/ Additional Information (to be provided if a 'No' answer has been selected above): Please see HMP Memo in Attachment 2. Critical Coarse Sediment Yield Areas* *This Section only required if hydromodification management requirements apply Based on the maps provided within the WMAA, do potential critical coarse sediment yield areas exist within the project drainage boundaries? □Yes [8J No, No critical coarse sediment yield areas to be protected based on WMAA maps If yes, have any of the optional analyses presented in Section 6.2 of the BMP Design Manual been performed? □ 6.2.1 Verification of Geomorphic Landscape Units (GLUs) Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment D 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite □ No optional analyses performed, the project will avoid critical coarse sediment yield areas identified based on WMAA maps If optional analyses were performed, what is the final result? □ No critical coarse sediment yield areas to be protected based on verification of GLUs onsite □ Critical coarse sediment yield areas exist but additional analysis has determined that protection is not required. Documentation attached in Attachment 8 of the SWQMP. □ Critical coarse sediment yield areas exist and require protection. The project will implement management measures described in Sections 6.2.4 and 6.2.5 as applicable, and the areas are identified on the SWQMP Exhibit. Discussion / Additional Information: Please refer to CCSYA exhibit in Attachment 2. Flow Control for Post-Project Runoff" *This. Section onlv reauired if hvdromodification manaaement reauirements annlv List and describe point(s) of compliance (POCs) for flow control for hydromodification management (see Section 6.3.1 ). For each POC, provide a POC identification name or number correlating to the project's HMP Exhibit and a receiving channel identification name or number correlating to the project's HMP Exhibit. Runoff from the LEGOLAND site is conveyed to two regional BMPs. From the BMPs the runoff is discharged by outlets structures that connect to the existing MS4 system and drain southerly into the Encinas Creek Basin. Has a geomorphic assessment been performed for the receiving channel(s)? □ No, the low flow threshold is 0.1 Q2 ( default low flow threshold) D Yes, the result is the low flow threshold is 0.1 Q2 D Yes, the result is the low flow threshold is 0.3Q2 [8J Yes, the result is the low flow threshold is 0.5Q2 If a geomorphic assessment has been performed, provide title, date, and preparer: The City of Carlsbad has approved a Susceptibility Analysis prepared by Chang Consultants for the Creek receiving the runoff from LEGOLAND, and it has been determined that such creek has low susceptibility. Consequently, a low susceptibility threshold will be used in this report. Hydromodification Screening for Legoland Parking Structure, 6/6/2016. Chang Consultants. Discussion/ Additional Information: (optional) I I I ·I ,, ,, II I ,, I I I I ,, I I I I: -1 I I! I I I I I ,, 1; I I I 1 Other Site Requirements and Constraints When applicable, list other site requirements or constraints that will influence storm water management design, such as zoning requirements including setbacks and open space, or City codes governing minimum street width, sidewalk construction, allowable pavement types, and drainage requirements. No other site requirements and or constraints impacted the design. Optional Additional Information or Continuation of Previous Sections As Needed This space provided for additional information or continuation of information from previous sections as needed. Not needed ---------------1 {'cicyof Carlsbad STANDARD PROJECT REQUIREMENT CHECKLIST E-36 Development Services Land Development Engineering 1635 Faraday Avenue (760) 602-2750 www.carlsbadca.gov I :I 1-------------------P_ro_j_ec_t_l_nf_o_r_m_a_ti_o_n _________________ ---1) Project Name: LEGOLAND LLC H20 ~P_r_o_je-ct_i_D_: _s_D_P_1_s~-2~6-/C_D_P_1s_-_s_o ____________________________ ~J DWG No. or Building Permit No.: ---' - Source Control BMPs ----- All development projects must implement source control BMPs SC-1 through SC-6 where applicable and feasible. See Chapter 4 and Appendix E.1 of the BMP Design Manual for information to implement source control BMPs shown in this checklist. Answer each category below pursuant to the following. • "Yes" means the project will implement the source control BMP as described in Chapter 4 and/or Appendix E.1 of the Model BMP Design Manual. Discussion/justification is not required. • "No" means the BMP is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed. • "N/A" means the BMP is not applicable at the project site because the project does not include the feature that is addressed by the BMP (e.g., the project has no outdoor materials storage areas). Discussion/justification may be provided. Source Control Requirement Applied? SC-1 Prevention of Illicit Discharges into the MS4 ~Yes □No ON/A Discussion/justification if SC-1 not implemented: SC-2 Storm Drain Stenciling or Signage ~Yes □No ON/A Discussion/justification if SC-2 not implemented: SC-3 Protect Outdoor Materials Storage Areas from Rainfall, Run-On, Runoff, and Wind ~Yes □No ON/A Dispersal Discussion/justification if SC-3 not implemented: No outdoor storage areas proposed on project site. E-36 Page 1 of 4 Revised 03/16 ,-J I I I I ·I I ,, I t -, I :1 ' I _I I I I I ' I. I I I -, I. ,.' I I_ ,. :1 ,_ I -- -Source Control Requirement (continued) Applied? SC-4 Protect Materials Stored in Outdoor Work Areas from Rainfall, Run-On, Runoff, and [ZIYes □No ON/A Wind Dispersal Discussion/justification if SC-4 not implemented: No outdoor work areas proposed. SC-5 Protect Trash Storage Areas from Rainfall, Run-On, Runoff, and Wind Dispersal [ZIYes □No ON/A Discussion/justification if SC-5 not implemented: SC-6 Additional BMPs based on Potential Sources of Runoff Pollutants must answer for each source listed below and identify additional BMPs. (See Table in Appendix E.1 of BMP Manual for guidance). (Copied from LLC H20) fZI On-site storm drain inlets [ZIYes □No ON/A □ Interior floor drains and elevator shaft sump pumps □Yes □No [ZIN/A □ Interior parking garages □Yes □No [ZIN/A □ Need for future indoor & structural pest control □Yes □No [ZIN/A □ Landscape/Outdoor Pesticide Use □Yes □No [ZIN/A fZI Pools, spas, ponds, decorative fountains, and other water features [ZIYes □No ON/A fZI Food service [ZIYes □No ON/A □ Refuse areas □Yes □No [ZIN/A □ Industrial processes □Yes □No [ZIN/A fZI Outdoor storage of equipment or materials [ZIYes □No ON/A □ Vehicle and Equipment Cleaning □Yes □No [ZIN/A □ Vehicle/Equipment Repair and Maintenance □Yes □No [ZIN/A □ Fuel Dispensing Areas □Yes □No [ZIN/A □ Loading Docks □Yes □No [ZIN/A □ Fire Sprinkler Test Water □Yes □No [ZIN/A □ Miscellaneous Drain or Wash Water [ZIYes □No ON/A fZI Plazas, sidewalks, and parking lots [ZIYes □No ON/A For "Yes" answers, identify the additional BMP per Appendix E.1. Provide justification for "No" answers. • Mark all inlets with the words "No Dumping! Flows to Bay" or similar. Maintain and periodically repaint or replace inlet markings. • Final landscape plans will accomplish all of the following: Design landscaping to minimize irrigation and runoff, to promote surface infiltration where appropriate, and to minimize the use of fertilizers and pesticides that can contribute to storm water pollution. Where landscaped areas are used to retain or detain storm water, specify plants that are tolerant of periodic saturated soil conditions. Consider using pest-resistant plants, especially adjacent to hardscape. To ensure successful establishment, select plants appropriate to site soils, slopes, climate, sun, wind, rain, land use, air movement, ecological consistency, and plant interactions. Maintain landscaping using minimum or no pesticides. • Move loaded and unloaded items indoors as soon as possible. ' • Provide a means to drain fire sprinkler test water to the sanitary sewer . • 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. Site Design BMPs All development projects must implement site design BMPs SD-1 through SD-8 where applicable and feasible. See Chapter 4 and Appendix E.2 thru E.6 of the BMP Design Manual for information to implement site design BMPs shown in this checklist. Answer each category below pursuant to the following. • "Yes" means the project will implement the site design BMPs as described in Chapter 4 and/or Appendix E.2 thru E.6 of the Model BMP Design Manual. Discussion/ justification is not required. • "No" means the BMPs is applicable to the project but it is not feasible to implement. Discussion/justification must be provided. Please add attachments if more space is needed. • "N/A" means the BMPs is not applicable at the project site because the project does not include the feature that is addressed by the BMPs (e.g., the project site has no existing natural areas to conserve). Discussion/justification may be provided. Source Control Requirement I Applied? SD-1 Maintain Natural Drainage Pathways and Hydrologic Features I □Yes I □No I [8]N/A Discussion/justification if SD-1 not implemented: Site is currently mass graded and developed. No natural drainage pathways/features exists onsite. SD-2 Conserve Natural Areas, Soils, and Vegetation I □Yes I □No I [8]N/A Discussion/justification if SD-2 not implemented: Site is currently mass graded and developed. SD-3 Minimize Impervious Area I □Yes I □No l [8]N/A Discussion/justification if SD-3 not implemented: Site is currently mass graded and developed. SD-4 Minimize Soil Compaction I [8]Yes I □No I ON/A Discussion/justification if SD-4 not implemented: Proposed Regional BMPs to be uncompacted. SD-5 Impervious Area Dispersion I [8]Yes I □No I ON/A Discussion/justification if SD-5 not implemented: Direct runoff will reach proposed Regional BMPs. I I I I I I I I I ,I I I I I ,~ ,. I I ~I: I I/ I I I J I I 1, I\ I ,, Source Control Requirement (continued) I Applied? SD-6 Runoff Collection I □Yes I [8]No I ON/A Discussion/justification if SD-6 not implemented: Deemed infeasible as this is a regional basin used for alternative compliance. SD-7 Landscaping with Native or Drought Tolerant Species I [8]Yes I □No I □NIA Discussion/justification if SD-7 not implemented: Drought tolerant plants, but more specifically native plants recommended for regional biofiltration facilities will be selected SD-8 Harvesting and Using Precipitation I □Yes I [8]No I □NIA Discussion/justification if SD-8 not implemented: Deemed infeasible as this is a regional basin used for alternative compliance. SUMMARY OF PDP STRUCTURAL BMPS PDP Structural BMPs All PDPs must implement structural BMPs for storm water pollutant control (see Chapter 5 of the BMP Design Manual). Selection of PDP structural BMPs for storm water pollutant control must be based on the selection process described in Chapter 5. PDPs subject to hydromodification management requirements must also implement structural BMPs for flow control for hydromodification management (see Chapter 6 of the BMP Design Manual). Both storm water pollutant control and flow control for hydromodification management can be achieved within the same structural BMP(s). PDP structural BMPs must be verified by the City at the completion of construction. This may include requiring the project owner or project owner's representative to certify construction of the structural BMPs (see Section 1.12 of the BMP Design Manual). PDP structural BMPs must be maintained into perpetuity, and the City must confirm the maintenance (see Section 7 of the BMP Design Manual). Use this form to provide narrative description of the general strategy for structural BMP implementation at the project site in the box below. Then complete the PDP structural BMP summary information sheet for each structural BMP within the project (copy the BMP summary information page as many times as needed to provide summary information for each individual structural BMP). • Describe the general strategy for structural BMP implementation at the site. This information must describe how the steps for selecting and designing storm water pollutant control BMPs presented in Section 5.1 of the BMP Design Manual were followed, and the results (type of BMPs selected). For projects requiring hydromodification flow control BMPs, indicate whether pollutant control and flow control BMPs are integrated together or separate. Per section 5.1 of the BMP manual, it was determined that harvest/reuse and infiltration were infeasible. Hydromodifcation is required. There are no Critical Coarse Sediment Yield areas within the development envelope. Therefore biofiltration basins with partial retention (for hydromodification management, flood and pollutant control) were the BMPs selected for this project. Two regional biofiltration basins with partial retention are located within the project site and are responsible for handling hydromodification requirements for the project. In developed conditions, the basins will have a surface depth and a riser spillway structure (see dimensions in Table 3). Flows will then discharge from the basins via the outlet stand structures or infiltrate through the amended soil and discharged by low flow orifices. The riser structures will act as spillways such that peak flows can be safely discharged to the receiving storm drain system. [Continue on next page as necessary.] I I I I ,, I I I I I I I I I I I I I I/ I I I I I I I [Continued from previous page -This page is reserved for continuation of description of general strategy for structural BMP implementation at the site.] Below the surface, the bioretention will have a 1.5 ft layer of amended soil, a portion of which will consist of the existing soil (re-tilted, and re-vegetated with appropriate plants) and the rest of it will consist of a main trench in the center, 5.5 ft wide at surface depth, 2 ft wide at bottom depth, to properly place the French Drain system. The trench will have new amended soil, filter layer and pea- gravel layer plus the horizontal French Drain pipe, controlled downstream from hydromodification purposes. VARIES BIOFlL TRA TION FOOTPRINT 5.5' TOP OF FRENCH-DRAIN TRENCH "BURRITO WRAPPED" PIPE (SIZE & TYPE PER PLAN) -Structural BMP Surrimary Information [Copy this page as needed to provide information for each individual proposed structural BMP] Structural BMP ID No. LEGOLAND Regional Basin-1 DWG 498-2C Sheet No. 2, 3, 4, 5 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) □ Retention by biorete~tion (INF-2) D Retention by permeable pavement (INF-3) □ Partial retention by biofiltration with partial retention (PR-1) 181 Biofiltration (BF-1) □ Flow-thru treatment control included as pre-treatmenUforebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: D Pollutant control only D Hydromodification control only 181 Combined pollutant control and hydromodification control □ Pre-treatmenUforebay for another structural BMP □ Other (describe in discussion section below) Discussion (as needed): See detailed discussion in structural BMP section I I I -, I I I ., I I I I I I I -, I I I I I I I I I Structural BMP Summary Information [Copy this page as needed to provide information for each individual proposed structural BMP] Structural BMP ID No. LEGOLAND Regional Basin-2 DWG 498-2C Sheet No. 2 6 Type of structural BMP: D Retention by harvest and use (HU-1) D Retention by infiltration basin (INF-1) □ Retention by bioretention (INF-2) D Retention by permeable pavement (INF-3) □ Partial retention by biofiltration with partial retention (PR-1) ~ Biofiltration (BF-1) □ Flow-thru treatment control included as pre-treatment/forebay for an onsite retention or biofiltration BMP (provide BMP type/description and indicate which onsite retention or biofiltration BMP it serves in discussion section below) D Detention pond or vault for hydromodification management D Other (describe in discussion section below) Purpose: D Pollutant control only D Hydromodification control only ~ Combined pollutant control and hydromodification control □ Pre-treatment/forebay for another structural BMP □ Other (describe in discussion section below) Discussion (as needed): See detailed discussion in structural BMP section Attachment Seauence Attachment 1 a Attachment 1 b Attachment 1 c Attachment 1 d Attachment 1 e ATTACHMENT 1 BACKUP FOR PDP POLLUTANT CONTROL BMPS This is the cover sheet for Attachment 1. Check which Items are Included behind this cover sheet: Contents OMA Exhibit (Required) See DMA Exhibit Checklist on the back of this Attachment cover sheet. (24"x36" Exhibit typically required) Tabular Summary of DMAs Showing OMA ID matching OMA Exhibit, OMA Area, and OMA Type (Required)* *Provide table in this Attachment OR on OMA Exhibit in Attachmen_t 1 a Form 1-7, Harvest and Use Feasibility Screening Checklist (Required unless the entire project will use infiltration BMPs) Refer to Appendix B.3-1 of the BMP Design Manual to complete Form 1-7. Form 1-8, Categorization of Infiltration Feasibility Condition (Required unless the project will use harvest and use BMPs) Refer to Appendices C and D of the BMP Design Manual to complete Form 1-8. Pollutant Control BMP Design Worksheets / Calculations (Required) Refer to Appendices B and E of the BMP Design Manual for structural pollutant control BMP design guidelines Checklist 181 Included □ Included on DMA Exhibit in Attachment 1 a 181 Included as Attachment 1 b, separate from DMA Exhibit (See Regional BMP Tables) □ Included □ Not included because the entire project will use infiltration BMPs 181 Not Applicable 181 Included □ Not included because the entire project will use harvest and use BMPs 181 Included (Calculations associated with entire LEGOLAND area) I I I I I :1 I .I I I I I -1 I I I I I I I I I I I I :, I II ,, II ,, I I I I I -I I I Attachment la DMA Exhibit Use this checklist to ensure the required information has been included on the OMA Exhibit: The OMA Exhibit must identify: □ Underlying hydrologic soil group D Approximate depth to groundwater □Existing natural hydrologic features (watercourses, seeps, springs, wetlands) □ Critical coarse sediment yield areas to be protected (if present) □ Existing topography and impervious areas □ Existing and proposed site drainage network and connections to drainage offsite □ Proposed grading □ Proposed impervious features D Proposed design features and surface treatments used to minimize imperviousness □ Drainage management area (OMA) boundaries, OMA ID numbers, and OMA areas (square footage or acreage), and OMA type (i.e., drains to BMP, self-retaining, or self-mitigating) □Structural BMPs (identify location and type of BMP) I I I I I ,, I I I I LEGEND OMA BOUNDARY '10:'.: 'l-a:: l~ . a:: <(! -~ SOIL TYPE BOUNDARY HYDROLOGIC SOIL GROUP "A" HYDROLOGIC SOIL GROUP "8" HYDROLOGIC SOIL GROUP "D" ---- t;.. o o ~ ~ o o ~ ~l I .,. .,. 'I= ·1 .,. ,+ +.,..,. t\\\\\\\\J + + + + + + + + + + + + + + + THE C~QSSING DR CURRENT PROJECTS TREATED I BY REGIONAL BMPs WATER SLIDE WP -17 ii WATER ;;LIDE WP -17 PARKING MODIFICATION Ao,snJRBED = 0.56 AC PARKING MODIFICATION (only 0.14 acre disturbed LLCH20 HOTEL Ao,s1\JRBED = 0.1 4 AC over the larger project boundary shown ) I I LLCH20 HOTEL DARK RIDE JD-18 AoisnJRBED = 6. 962 AC W<~~«<sl DARK RIDE JD-18 REGIONAL BMP BASIN Ao,s1\JRBED = 0. 900 AC DRAINAGE BAS IN Al 1.644 AC Bl 64.403 AC D1 39.884 AC X1 -NORTH AREA 1 53.790 AC B2 0.827 AC D2 10.733 AC X2 -NORTH AREA 2 12. 710 AC -/AREA PER O'DA Y STUDY I A = 46.850 AC ----------I -------- Civil Engineering ~nvironmental Land Surveying 2442 Second Avenue San Diego, CA 92101 --- 150 75 ' ~ I I I I I I I I I 0 150 300 450 Consultants, In c. (619)232-9200 (619)232-9210 Fax SCALE: 1" = 150' I SH1EET I CIT Y OF CARLSBAD I SHEETS I f-----f-----+----------------t---t---t---+--i ENGINEERING DEPARTMENT l f----+----+--------------+----+--t----t---1 DATE INITIAL ENGINEER OF WORK REVISION DESCRIPTION 0M,\/1-1 1-II,, HYDROLOGY l•:.\'.H IBIT FOR: LEGOLAND REGIONAL BIOFILTRATTON & HYDROMODIFICATION FACILITY GR NO ~0 17 002:-, APPROVED: JASON S. GELDERT CITY ENGINEER RCE 63912 EXPIRES 9 30 18 DATE OWN BY: __ _ DATE INITIAL DATE INITI AL CHKD BY: __ _ OTHER APPROVAL CITY APPROVAL RVWD BY: PROJECT NO. SDP15-26 DRAWING NO. 498-2C I -.1 I ·I .,, -1 _ .. ,, --, -·I _.., ~1 ~1 -"I ~., ,, I :I 1· I Attachment lb DMA ID., Areas & Type .. -----~------------ Attachment lb : DMA ID, Areas and Type BMP Type Contributing Area for WQ Contributing Area for Hydromod Redevelopments Included 1 Biofiltration with A portion of Al, Bl, & Dl not to exceed an A portion of Al, Bl, & Dl not to exceed an WP-17, LLCH20, JD-18 & a portion partial retention equivalent area of 46.74(1) equivalent area of 70.79(1) of Parking Mod if. Phase II 2 Biofiltration with A portion of B2 & D2 not to exceed an A portion of B2 & D2 not to exceed an A portion of Parking Modification partial retention equivalent area of 4.8i1l equivalent area of 7.83(1) Phase II TOTAL: 51.612 acres (area equivalent) TOTAL: 78.617 acres (area equivalent) Note (1): Areas included here correspond to calculated areas (before 4 re-development project areas are sustracted) I I I I I I I I I I I I I I ,I I ii ., I I Attachment le Not Applicable I I I I I I I I I Attachment ld I Form 1-8 I I I I I I I I : I I I Part 1 -Full Infiltration Feasibility Screening Criteria Would infiltration of the full design volume be feasible from a physical perspective without any undesirable consequences that cannot be reasonably mitigated? Criteria Screening Question Is the estimated reliable infiltration rate below proposed facility locations greater than 0.5 inches per hour? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes No □ Infiltration is currently occurring in the existing detention basin at the capacity allowed by the natural soil. As (a) it is not possible to measure infiltration with conventional methods in an already saturated (and submerged) soil, and (b) as there are no existing impervious liners, infiltration will continue at the same unknown rate. For conservative purposes, and considering that most of the soil is type D (with a small area being type A), and for modeling purposes, the infiltration was assumed as f = 0.02 in/hr for hydromodification purposes, and considered negligible for water quality purposes. • • Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. 2 Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: □ See response to criteria 1. In addition, see separate Geotechnical Report associated with this SWQMP, prepared by NOVA, August 3, 2017. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. I I I I I I I I I I I I I I I I I .I I I I I I I I I I I I I I I I I ~---------------------~- i1 • Form 1-8 Page 2 of 4 Criteria 3 Screening Question Can infiltration greater than 0.5 inches per hour be allowed without increasing risk of groundwater contamination (shallow water table, storm water pollutants or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3_ Provide basis: See response to Criteria 1. Yes No □ Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion ofstudy / data source app licability. 4 Can infiltration greater than 0.5 inches per hour be allowed without causing potential water balance issues such as change of seasonality of ephemeral streams or increased discharge of contaminated groundwater to surface waters? The response to this _ Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. □ Provide basis: See response to Criteria 1. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability. Part 1 Result * If all answers to rows 1 - 4 are ''Yes" a full infiltration design is potentially feasible. The Oves feasibility screening category is Full Infiltration If any answer from row 1-4 is "No", infiltration may be possible to some extent but C8JNo would not generally be feasible or desirable to achieve a "full infiltration" design. Proceed to Part 2 *To be completed using gathered site informanon and best professional Judgment cons1dermg the definition of MEP in the MS4 Permit. Additional testing and/ or studies may be required by Agency /Jurisdictions to substantiate findings ------------~---~---------- -- - -----i Form 1-8 Page 3 of 4 1 Part 2 -Partial Infiltration vs. No Infiltration Feasibility Screening Criteria Would infiltration of water in any appreciable amount be physically feasible without any negative consequences that cannot be reasonably mitigated? Criteria 5 Screening Question Do soil and geologic conditions allow for infiltration in any appreciable rate or volume? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2 and Appendix D. Provide basis: Yes No □ Infiltration is currently occurring in the existing detention basin at the capacity allowed by the natural soil. As (a) it is not possible to measure infiltration with conventional methods in an already saturated (and submerged) soil, and (b) as there are no existing impervious liners, infiltration will continue at the same unknown rate. For conservative purposes, and considering that most of the soil is type D (with a small area being type A), and for modeling purposes, the infiltration was assumed as f = 0.02 in/hr for hydromodification purposes, and considered negligible for water quality purposes. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 6 Can Infiltration in any appreciable quantity be allowed without increasing risk of geotechnical hazards (slope stability, groundwater mounding, utilities, or other factors) that cannot be mitigated to an acceptable level? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.2. Provide basis: □ See response to criteria 5. In addition, see separate Geotechnical Report associated with this SWQMP, prepared by NOVA, August 3, 2017. Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Criteria 7 Screening Question Can Infiltration in any appreciable quantity be allowed without posing significant risk for groundwater related concerns (shallow water table, storm water pollutants or other factors)? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: See response to Criteria 5. Yes No □ Summarize findings of studies; provide reference to stuches, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. 8 Can infiltration be allowed without violating downstream water rights? The response to this Screening Question shall be based on a comprehensive evaluation of the factors presented in Appendix C.3. Provide basis: See response to Criteria 5. □ Summarize findings of studies; provide reference to studies, calculations, maps, data sources, etc. Provide narrative discussion of study/ data source applicability and why it was not feasible to mitigate low infiltration rates. Part 2 Result* If all answers from row 1-4 are yes then partial infiltration design is potentially feasible. Oves The feasibility screening category is Partial Infiltration. If any answer from row 5-8 is no, then infiltration of any volume is considered to be ~No infeasible within the drainage area. The feasibility screening category is No Infiltration. Note: 0.02 in/hr is considered negligible for practical purposes and the BMP has no infiltration. 33" 7'57"N 33" 7' 13"N 47(fill ;: iJ1 !!l 3 N A Hydrologic Soil Group-San Diego County Area, California (Legoland) 47= 470700 4700X) 4700:X:, 471CXXJ 471100 471axJ 47= 470700 4700X) 47= 4710C0 471100 471200 Map Scale: 1:6,720 if printed on A portrait (8.5'' x 11") sheet ---==c-.----====Melers 0 50 100 200 300 ----====---------========Feet 0 300 ~ 1200 1~ Map projection: Web Mercator Comer axirdinates: WGS84 Edge tics: IJTM Zore llN WGS84 USDA Natural Resources Web Soil Survey --=rtm Conservation Service National Cooperative Soil Survey 471:xxl 471400 471:xxl 471400 471500 471500 1/31 /2017 Page 1 of 4 33" 7'57"N 33" 7' i3"N Hydrologic Soil Group-San Diego County Area. California (legoland) MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons D A D AID D B D BID D C D CID D D D Not rated or not available Soil Rating Lines -A AID -B -BID C CID -D -" Not rated or not available Soil Rating Points ■ A AID ■ B ■ BID USDA Natural Resources -ea Conservation Service □ C CID ■ D □ Not rated or not available Water Features Streams and Canals Transportation M-+ Rails -Interstate Highways -US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area. such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required . This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area. California Survey Area Data: Version 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 1/31/2017 Page 2 of 4 Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Hydrologic Soil Group--Summary by Map Unit -San Diego County Area, California (CA638) Map unit symbol Map unit name Rating Acres in AOI F'ercent of AOI CbB Carlsbad gravelly loamy B 21.6 15.9% sand, 2 to 5 percent -- slopes LeE2 Las Flores loamy fine D 56.7 41.8% sand, 15 to 30 percent slopes, er oded MIC Marina loamy coarse B 54.8 40.4% sand, 2 to 9 percent slopes ScA Salinas clay, 0 to 2 C 0.4 0.3% percent slopes TuB Tujunga sand, 0 to 5 A 2.2 1.6% percent slopes Totals for Area of Interest 135.8 100.0% USDA Natural Resources Web Soil Survey = Conservation Service National Cooperative Soil Survey Legoland 1/31/2017 Page 3 of 4 I I I I I I I I I I I 1- I I I I I I I I I I I I I I I I I I I I I I I I I I Hydrologic Soil Group-San Diego County Area, California Description Hydrologic soil groups are based on estimates Qf runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (AID, B/D, and C/D). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (AID, B/D, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher USDA Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey Legoland 1/31/2017 Page 4 of 4 33" 7' SS"N 33" 7' 13" N 4700)'.) 4700)'.) N A Depth to Water Table-San Diego County Area, California (LEGOLAND Park) 470700 47C6'.XJ 47(00'.) 47100J 471100 471200 470700 47C6'.Xl 47(00'.) 47100J 471100 471200 Map Scale: 1:6,260 W printed on A portrait (8.5" x 11") sheet. --<===-----=====Meters 0 50 100 200 Dl -----=====---------========:::iFeet 0 300 ml 1200 1!0:J Map projection: 'Neb Mercator Corner coordinates: WGS84 ~ tics: UTM Zone 1 lN WGS84 USDA Natural Resources Web Soil Survey ':iiF Conservation Service National Cooperative Soil Survey 471:nl 471400 471:xxl 471400 471500 471500 ;: !!l ~ ~ 5/18/2017 Page 1 of 3 33" 7' SS"N 33" 7' 13"N Depth to Water Table-San Diego County Area, California (LEGOLAND Park) MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons 0-25 D 25-50 D 50 -100 D 100-150 D 150 -200 -> 200 D Not rated or not available Soil Rating Lines ~ 0-25 ,.-, 25 -50 -,, 50 -100 ,. ,, 100 -150 150-200 ~ > 200 -" Not rated or not available Soil Rating Points ■ 0-25 □ 25 -50 □ □ 50 -100 100 -150 150-200 ■ > 200 USDA Natural Resources -iiiii Conservation Service □ Not rated or not available Water Features Streams and Canals Transportation +++ Rails ...,,,,,, Interstate Highways -US Routes Major Roads Local Roads Background -Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 5/18/2017 Page 2 of 3 Depth to Water Table-San Diego County Area, California LEGOLAND Park Depth to Water Table Depth to Water Table-Summary by Map Unit -San Diego County Area, California (CA638) Map unit symbol Map unit name Rating (centimeters) Acres in AOI Percent of AOI CbB Carlsbad gravelly loamy >200 17.7 sand, 2 to 5 percent slopes LeE2 Las Flores loamy fine >200 54.3 sand, 15 to 30 percent slopes, er oded MIC Marina loamy coarse >200 53.5 sand, 2 to 9 percent slopes ScA Salinas clay, 0 to 2 >200 0.4 percent slopes TuB Tujunga sand, 0 to 5 >200 1.9 percent slopes Totals for Area of Interest 127.8 Description "Water table" refers to a saturated zone in the soil. It occurs during specified months. Estimates of the upper limit are based mainly on observations of the water table at selected sites and on evidence of a saturated zone, namely grayish colors (redoximorphic features) in the soil. A saturated zone that lasts for less than a month is not considered a water table. This attribute is actually recorded as three separate values in the database. A low value and a high value indicate the range of this attribute for the soil component. A "representative" value indicates the expected value of this attribute for the component. For this soil property, only the representative value is used. Rating Options Units of Measure: centimeters Aggregation Method: Dominant Component Component Percent Cutoff: None Specified Tie-break Rule: Lower Interpret Nulls as Zero: No Beginning Month: January Ending Month: December Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 13.9% 42.5% 41.9% 0.3% 1.5% 100.0% 5/18/2017 Page 3 of 3 I I I I I I I I I I I I I I I I I I I ; I I I I I ii I :1 ·1 I I I I I I I I I I Attachment le BMP Design Worksheets GENERAL INFORMATION/ CALCULATIONS FOR WATER QUALITY COMPLIANCE Table 1: Water Quality Equivalent Area Use most constraining factor between (a) Biofilter 1.5 times the DCV; (b) Store 75% DCV in pores and (c) sizing factor. Solution: (c): sizing factor VARIABLE BMP-1 BMP-2 Area of BMP, AsMP (sq-ft): 29826 3429 Sizing Factor (SF, Table B-5.2, San Diego BMP Manual) 0.01465 0.01615 Area Equiv. (acres): Aeq = AsMP/SF/43560 46.738 4.874 Total Area Equivalent: 51.612 acres Total used (4 Projects, Table 3): 5.846 acres TOT Remaining (after 4 projects): 45.766 acres Table 2: Hypothetical Partition of Contributing Areas per Land Use BMP-1 BMP-2 SUB-AREAS %Area' .. , %DCV'L' %Area' .. , %DCV'L' Impervious, roof (IR) 15% 19.3% 5% 6.1% Impervious, parking+roads (Ip) 60% 77.1% 75% 91.2% Pervious, landscape (PL) 25% 3.6% 20% 2.7% C = 0.9·(IR+lp)+O.l·PL 0.70 0.74 A= Aeq/C (acres) 66.768 6.587 Notes: (1) : % Area assumed as an approximation of existing conditions (2): % DCV is used in Worksheet B.5-2, taken from the City of San Diego Manual. %DCV = %Area/C Table 3. Partition of 4 Re-Development Projects to Drain to BMPs PROJECT IMPERV .PERV • Never Out TOTAL13l C (acres) (acres) (acres) (to BMP, ac) Water Slide 0.305 0.255 0.097 0.56 0.536 Parking Modif. Phase II (ll 0.14 0 0 0.14 0.900 LLCH20 Hotel (2l 5.237 1.725 0.138 6.962 0.702 Dark Ride 0.555 0.345 0 0.90 0.593 TOTAL 6.237 2.325 0.235 8.562 0.683 Notes: (1) : Only accounts for the impervious area replaced (2): Certain assumptions were ma~e because pre-dev. area~ post-dev. area in the original DCI Report .. Eq. Area 0.300 0.126 4.886 0.534 5.846 Total area= existing calculated area. Total Post-area= assumed correct. Total never draining out= pool area. lmperv = Tot -perv -pool. (3): Total refers to the area draining to BMPs downstream and excludes the area never draining out (pools, for example) I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I BMPl Worksheet B.2-1. DCV Design Ca:Rture Volume Worksheet B-2.1 1 85th percentile 24-hr storm d= 0.59 inches depth from Figure B.1-1 2 Area tributary to BMP (s) A= 55.576 acres Area weighted runoff factor 3 (estimate using Appendix C= 0.700 unitless (l) B.1.1 and B.2.1) 4 Street trees volume TCV= 0 cubic-feet reduction 5 Rain barrels volume RCV= 0 cubic-feet reduction Calculate DCV = 6 (3630 x C x d x A) -TCV -DCV= 83319 cubic-feet RCV (1): C is calculated in Table 2, according to the partion of the area between landscape and impervious areas. BMP2 Worksheet B.2-1. DCV Design Capture Volume Worksheet B-2.1 1 85th percentile 24-hr storm d= 0.59 inches depth from Figure B.1-1 2 Area tributary to BMP (s) A= 4.853 acres Area weighted runoff factor 3 ( estimate using Appendix C= 0.740 unitless(l) B.1.1 and B.2.1) 4 Street trees volume TCV= 0 cubic-feet reduction 5 Rain barrels volume RCV= 0 cubic-feet reduction Calculate DCV = 6 (3630 x C x d x A) -TCV -DCV= 7691 cubic-feet RCV (1): C is calculated in Table 2, according to the partion of the area between landscape and impervious areas. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I BMP Name: BMP-1 Worksheet B.5-1 _·\ 1 Area Draining to the BMP 2 Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) 3 85th percentile 24-hour rainfall depth 4 Design Capture volume [ Line 1 x Line 2 x ( Line 3/12)] BMP Parameters 5 Surface ponding [6 inch minimum, 12 inch maximum] 6 Media thickness [18 inches minimum], also add mulch layer thickness to 7 Aggregate storage above underdrain invert (12 inches typical) -use 0 inches if the aggregate is not over the entire bottom surface area 8 Aggregate storage below underdrain invert (3 inches minimum) -use 0 inches if the a re ate is not over the entire bottom surface area 9 Freely drained pore storage of the media 10 Porosity of aggregate storage 11 Media filtration rate to be used for sizing ( maximum filtration rate of 5 Baseline Calculations 12 Allowable routing time for sizing 13 Depth filtered during storm [ Line 11 x Line 12 ] 14 Depth of Detention Storage [Line 5 + (Line 6 x Line 9) + (Line 7 x Line 10) + (Line 8 x Line 10)] 15 Total Depth Treated [Line 13 + Line 14] Option 1 -Biofilter 1.5 times the DCV • 16 Required biofiltered volume [1.5 x Line 4] 17 Required Footprint [Line 16/ Line 15] x 12 Option 2 -Store 0.75 of remaining DCV in pores and ponding 18 Required Storage (surface+ pores) Volume [0.75 x Line 4] 19 Required Footprint [Line 18/ Line 14] x 12 Footprint of the BMP 20 BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum 21 Minimum BMP Footprint [Line 1 x Line 2 x Line 20] 22 Footprint of the BMP = Maximum(Minimum(Line 17, Line 19), Line 21) 2909403 sq. ft. 0.700 0.59 inches 100132 cu.ft. 30.58 inches 18 inches 0 inches 0 inches 0.2 in/in 0.4 in/in 5 in hr 6 hours 30 inches 34.18 inches 64.18 inches 150198 cu.ft. 28083 sq.ft. 75099 cu.ft. 26366 sq.ft. 0.01465 29826 sq.ft. 29826 sq.ft. BMP Name: BMP-2 Worksheet B.5-1 1 Area Draining to the BMP 2 Adjusted runoff factor for drainage area (Refer to Appendix B.1 and B.2) 3 85th percentile 24-hour rainfall depth 4 Design Capture volume [ Line 1 x Line 2 x ( Line 3/12)] BMP Parameters 5 Surface ponding [6 inch minimum, 12 inch maximum] 6 Media thickness [18 inches minimum], also add mulch layer thickness to 7 Aggregate storage above underdrain invert (12 inches typical) -use 0 inches if the aggregate is not over the entire bottom surface area 8 Aggregate storage below underdrain invert (3 inches minimum) -use 0 inches if the a re ate is not over the entire bottom surface area 9 Freely drained pore storage of the media 10 Porosity of aggregate storage 11 Media filtration rate to be used for sizing (maximum filtration rate of 5 Baseline Calculations 12 Allowable routing time for sizing 13 Depth filtered during storm [ Line 11 x Line 12] 14 Depth of Detention Storage [Line 5 + (Line 6 x Line 9) + (Line 7 x Line 10) + (Line 8 x Line 10)] 15 Total Depth Treated [Line 13 + Line 14] Option 1 -Biofilter 1.5 times the DCV 16 Required biofiltered volume [1.5 x Line 4] 17 Required Footprint [Line 16/ Line 15] x 12 Option 2 -Store 0.75 of remaining DCVin pores and ponding 18 Required Storage (surface+ pores) Volume [0.75 x Line 4] 19 Required Footprint [Line 18/ Line 14] x 12 Footprint of the BMP 286925 sq. ft. 0.740 0.59 inches 10439 cu.ft. 23.24 inches 18 inches 0 inches 0 inches 0.2 in/in 0.4 in/in 5 in hr 6 hours 30 inches 26.84 inches 56.84 inches 15659 cu.ft. 3306 sq.ft. 7829 cu.ft. 3501 sq.ft. 20 BMP Footprint Sizing Factor (Default 0.03 or an alternative minimum 0.01615 21 Minimum BMP Footprint [Line 1 x Line 2 x Line 20] 3429 sq.ft. I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I BMPl Worksheet B.5-2 (Modified): Calculation of Alternative Minimum Footprint Sizing Factor Worksheet B.5-2 / Modified 1 Area Draining to the BMP 2 Adjusted Runoff Factor for Drainage Area 3 Load to Clog (See Table B.5-3 for guidance; Le) 4 Allowable Period to Accumulate Clogging Load (Td Volume Weighted EMC Calculation Land Use Single Family Residential Commercial Industrial Education Transportation Multi-family Residential Roof Runoff Low Traffic Areas Open Space Other, Specify: Other, Specify: Fraction of Total ocv131 0.771 0.193 0.036 5 Volume weighted EMC (sum of all products) BMP Parameters TSS EMC (mg/L) 123 128 125 132 78 40 14 216 6 If pre-treatment measures are included, apply an adjustment of 25% 7 Average Annual Precipitation 8* Average Annual Runoff (Line 7 x 43,560 x Line 1 /12) x Line 2 9 Average Annual TSS Load 10 BMP footprint needed 11 Alternative minimum footprint sizing factor NOTES 2,908,435 sq-ft 0.700 2.5 lb/sq-ft 1 10.0 years Product 60.17 2.70 7.71 70.59 mg/L 52.94 mg/L141 13.3 inches 2256461 cu-ft/yr 7454 lb/yr 29816 sq-ft 0.01465 (1): Average between 2 lowest loads of Table B.5-3 of the San Diego HMP Manual used as vegetative cover will be more than 50%. (2): 10 year is the standard value recommended in the San Diego HMP Manual for a major maintenance of the amended soil (3): Fraction of DCV for roof, landscape and transportation calculated in Table 2 (4): Forebay with gabion walls considered as a pre-treatment to the amended soil as large particles, leaves and trash will be collected there before reaching the amended soil and will reduce the load of sediments downstream *: Correction prepared by REC, from the error shown in the Original Table B.5-2 of the San Diego HMP Manual um BMP2 Worksheet B.5-2 {Modified): Calculation of Alternative Minimum Footprint Sizing Factor Worksheet B.5-2 / Modified 1 Area Draining to the BMP 2 Adjusted Runoff Factor for Drainage Area 3 Load to Clog (See Table B.5-3 for guidance; Le) 4 Allowable Period to Accumulate Clogging Load (Td Volume Weighted EMC Calculation Land Use Single Family Residential Commercial Industrial Education Transportation Multi-family Residential Roof Runoff Low Traffic Areas Open Space Other, Specify: Other, Specify: Fraction of Total DCV131 0.912 0.061 0.027 5 Volume weighted EMC (sum of all products) BMP Parameters TSS EMC (mg/L) 123 128 125 132 78 40 14 216 6 If pre-treatment measures are included, apply an adjustment of 25% 7 Average Annual Precipitation 8* Average Annual Runoff (Line 7 x 43,560 x Line 1 /12) x Line 2 9 Average Annual TSS Load 10 BMP footprint needed 11 Alternative minimum footprint sizing factor NOTES 286,922 sq-ft 0.740 2.5 lb/sq-ft 1 10.0 years Product 71.15 0.85 5.84 77.84 mg/L 58.38 mg/L14l 13.3 inches 235324 cu-ft/yr 857 lb/yr 3429 sq-ft 0.01615 (1): Average between 2 lowest loads ofTable B.5-3 of the San Diego HMP Manual used as vegetative cover will be more than 50%. (2): 10 year is the standard value recommended in the San Diego HMP Manual for a major maintenance of the amended soil (3): Fraction of DCV for roof, landscape and transportation calculated in Table 2 (4): Forebay with gabion walls considered as a pre-treatment to the amended soil as large particles, leaves and trash will be collected there before reaching the amended soil and will reduce the load of sediments downstream •: Correction prepared by REC, from the error shown in the Original Table B.5-2 of the San Diego HMP Manual nm I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I ATTACHMENT 2 BACKUP FOR PDP HYDROMODIFICATION CONTROL MEASURES [This is the cover sheet for Attachment 2.] Indicate which Items are Included behind this cover sheet: Attachment Contents Checklist Sequence Attachment 2a Hydromodification Management [8J Included Exhibit (Required) Attachment 2b Management of Critical Coarse [8JExhibit showing project drainage Sediment Yield Areas (WMAA Exhibit boundaries marked on WMAA is required, additional analyses are Critical Coarse Sediment Yield optional) Area Map (Required) See Section 6.2 of the BMP Design Optional analyses for Critical Coarse Manual. Sediment Yield Area Determination D 6.2.1 Verification of Geomorphic Landscape Units Onsite D 6.2.2 Downstream Systems Sensitivity to Coarse Sediment □ 6.2.3 Optional Additional Analysis of Potential Critical Coarse Sediment Yield Areas Onsite Attachment 2c Geomorphic Assessment of Receiving □ Not performed Channels (Optional) [8J Included See Section 6.3.4 of the BMP Design Manual. Attachment 2d Flow Control Facility Design and [8J Included Structural BMP Drawdown □Submitted as separate stand-alone Calculations (Required) document See Chapter 6 and Appendix G of the BMP Design Manual i I I I I :1 I I I I I I I I I I I 'I I I Attachment 2a Hydromodification Management Exhibit (See DMA Exhibit, Attachment lb) Use this checklist to ensure the required information has been included on the • Hydromodification Management Exhibit: The Hydromodification Management Exhibit must identify: [8J Underlying hydrologic soil group [8J Approximate depth to groundwater (not applicable as infiltration is negligible) [8J Existing natural hydrologic features ( watercourses, seeps, springs, wetlands) [8J Critical coarse sediment yield areas to be protected (if present: not applicable as not present) [8J Existing topography [8J Existing and proposed site drainage network and connections to drainage offsite [8J Proposed grading [8J Proposed impervious features [8J Proposed design features and surface treatments used to minimize imperviousness (not applicable as the project is a regional facility that in itself does not generate impervious surfaces, and impervious surfaces will be adjusted by individual future re-development projects) [8J Point(s) of Compliance (POC) for Hydromodification Management [8J Existing and proposed drainage boundary and drainage area to each POC (when necessary, create separate exhibits for pre-development and post-project conditions) [8J Structural BMPs for hydromodification management (identify location, type of BMP, and size/detail) I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Attachment 2b Critical Coarse Sediment Yield Areas-WMAA Exhibit I I LEGEND C ~ Project Site - Potential Critical Coarse Sediment Yield Areas Consultants, Inc. Legoland •--==---==---Feet 0 250 500 1 Aerial Source: ESRI Basemap May 2017 I I I I I 11 I ! I, I Attachment 2c I Geomorphic Assessment of Receiving Channels I I I I I I I I I I HYDROMODIFICATION SCREENING FOR LEGOLANDPARKINGSTRUCTURE June 6, 2016 Wayne W. Chang, MS, PE 46548 Ohang(Bo]oo[fiurrrn Civil Engineering • Hydrology • Hydraulics • Sedimentation P.O. Box 9496 Rancho Santa Fe, CA 92067 (8S8) 692-0760 FOR REVIEW ONLY I I I I ~ I I ,'.I I I I -1 -I I I I I I I I I I I-. 1, I I I I I 11 I I .I I ,I I II I I I, -TABLE OF CONTENTS - Introduction ................................................................................................................................... 1 Domain of Analysis .......................................................... ; ........................................................... 2 Initial Desktop Analysis ................................................................................................................ 4 Field Screening ............................................................................................................................. 5 Conclusion .................................................................................................................................... 9 Figures ......................................................................................................................................... 10 APPENDICES A. SCCWRP Initial Desktop Analysis B. SCCWRP Field Screening Data MAP POCKET Study Area Exhibit As-Built Drawings (Sheet 11 from Drawing 381-6 and Sheet 2 from Drawing 381-6A) FOR REVIEW ONLY INTRODUCTION The City of Carlsbad's 2016, Carlsbad BMP Design Manual, outlines low flow thresholds for hydromodification analyses. The thresholds are based on a percentage of the pre-project 2-year flow (Q2), i.e., 0.1 Q2 (low flow threshold and high susceptibility to erosion), 0.3Q2 (medium flow threshold and medium susceptibility to erosion), or 0.5Q2 (high flow threshold and low susceptibility to erosion). A threshold of 0.lQ2 represents a downstream receiving conveyance system with a high susceptibility to erosion. This is the default value used for hydromodification analyses and will result in the most conservative (greatest) on-site facility sizing. A threshold of 0.3Q2 or 0.5Q2 represents downstream receiving conveyance systems with a medium or low susceptibility to erosion, respectively. In order to qualify for a medium or low susceptibility rating, a project must perform a channel screening analysis based on a "hydromodification screening tool" procedure developed by the Southern California Coastal Water Research Project (SCCWRP). The SCCWRP results are compared with the critical shear stress calculator results from the County of San Diego's Critical Flow Calculator spreadsheet to establish the appropriate susceptibility threshold of low, medium, or high. CITY OF OCEANSIDE 'la PACIFIC CITY Of' ENCINITAS Vicinity Map OF MARCOS This report provides hydromodification screening analyses for the Legoland Parking Structure project being designed by Nasland Engineering. The proposed parking structure will be constructed within the northeast portion of the. existing staff and visitor parking lot just west of 1 I I I I I I I I I I I I I ·1 I I I I. I I I I I· I I I I I I The Crossings Drive (see the Vicinity Map). A portion of the existing asphalt parking lot will be demolished in order to construct the new parking structure. Under pre-project conditions, storm runoff from the project footprint sheet flows in a southerly direction and is ultimately collected by a storm drain system that conveys the runoff to a detention basin near the southeast comer of the parking lot. The detention basin is immediately northwest of the intersection of Palomar Airport Road and The Crossings Drive. The runoff is conveyed south out of the detention basin by double 48-inch reinforced concrete pipes. The pipes cross Palomar Airport Road and discharge into a natural channel on the south side of the street, i.e., the discharge location is southwest of the intersection of Palomar Airport Road and Hidden Valley Road (The Crossings Drive becomes Hidden Valley Road south of Palomar Airport Road). The natural channel conveys the runoff westerly into Encinas Creek, which continues west approximately 1.1 miles to the Pacific Ocean. Under post-project conditions, the project runoff will be treated by a biofiltration basin constructed along the southerly edge of the parking structure. The runoff will then be conveyed by pipe to the existing storm drain system in The Crossings Drive. From here, the flow will be conveyed to the existing detention basin, natural channel, Encinas Creek, and Pacific Ocean similar to existing conditions. The SCCWRP screening tool requires both office and field work to establish the vertical and lateral susceptibility of a natural downstream receiving channel to erosion. The vertical and lateral assessments are performed independently of each other although the lateral results can be affected by the vertical rating. A screening analysis was performed to assess the low flow threshold for the project's point of compliance, which is the first location downstream of the site containing a natural drainage course with the potential for erosion. In this case, the point of compliance is at the beginning of the natural channel southwest of the intersection of Palomar Airport Road and Hidden Valley Road (see the Study Area Exhibit in the map pocket). The initial step in performing the SCCWRP screening analysis is to establish the domain of analysis and the study reaches within the domain. This is followed by office and field components of the screening tool along with the associated analyses and results. The following sections cover these procedures in sequence. DOMAIN OF ANALYSIS SCCWRP defines an upstream and downstream domain of analysis, which establish the study limits. The County of San Diego's HMP specifies the downstream domain of analysis based on the SCCWRP criteria. The HMP indicates that the downstream domain is the first point where one of these is reached: • at least one reach downstream of the first grade contro~ point • tidal backwater/lentic waterbody • equal order tributary 2 • accumulation of 50 percent drainage area for stream systems or 100 percent drainage area for urban conveyance systems (storm drains, hardened channels, etc.) The upstream limit is defined as: • proceed upstream for 20 channel top widths or to the first grade control point, whichever comes first. Identify hard points that can check headward migration and evidence of active headcutting. SCCWRP defines the maximum spatial unit, or reach (a reach is circa 20 channel widths), for assigning a susceptibility rating within the domain of analysis to be 200 meters (656 feet). If the domain of analysis is greater than 200 meters, the study area should be subdivided into smaller reaches of less than 200 meters for analysis. Most of the units in the HMP's SCCWRP analysis are metric. Metric units are used in this report only where given so in the HMP. Otherwise English units are used. Downstream Domain ofAnalysis The downstream domain of anaiysis for a study area is determined by assessing and comparing the four bullet items above. As discussed in the Introduction, the project has a single point of compliance (POC) at the double 48-inch RCP outlet into the natural channel. The downstream domain of analysis is selected below this POC. Per the first bullet item, the first permanent grade control point was located below the POC through a site investigation and review of as-built drawings. Sheet 11 from as-built drawing 3 81- 6 (included in map pocket) shows that a section of the channel bed and banks are riprap-lined approximately 545 feet downstream of the POC. The as-built shows that this location also contains a riprap berm crossing the channel bed. The riprap was observed in the field. The riprap channel bed, banks, and berm act as a permanent grade control, which will maintain the upstream channel bed elevations. Therefore, the riprap meets the first grade control criteria. The second bullet item is the tidal backwater or lentic (standing or still water such as ponds, pools, marshes, lakes, etc.) waterbody location. A lentic waterbody does not exist below the POC. On the other hand, the nearest tidal backwater occurs where Encinas Creek discharges into the Pacific Ocean. The Pacific Ocean is below the riprap grade control, so the second bullet criteria will not govern over the first bullet criteria for establishing the downstream domain of analysis location. The final two bullet items are based on 50 and 100 percent tributary drainage areas (in this case, the chahn.el is in an urban area, so the 100 percent criteria applies). The 100 percent criteria from bullet item 4 is essentially the same as an equal order tributary from bullet item 3. According to sheet 2 from as-built drawing 381-6A (included in the map pocket), the natural channel below the POC confluences with Encinas Creek at the riprap. Encinas Creek extends over 2.3 miles upstream to El Camino Real, so its watershed area is much larger than the drainage area tributary to the natural channel. The natural channel accumulates over 100 percent drainage area at the confluence with Encinas Creek. Therefore, the tributary area criteria is met at the confluence, which corresponds to the riprap location. 3 I I I -I I I ·I I I I I I I I I I I I I I I I I I I Based on the above information, the downstream domain of analysis location below the POC occurs at the riprap in the natural channel. The first, third, and fourth bullet criteria are met at this location, which is approximately 545 feet downstream of the POC. Upstream Domain of Analysis The upstream domain of analysis must be established for the POC. The outlet of the double 48- inch RCPs into the natural channel is the upstream end of the receiving natural channel. Since the area upstream of the POC is not an erodible channel, the POC establishes the upstream domain of analysis location. Study Reaches within Domain of Analysis The total domain of analysis ( or overall study reach) extends from the POC to the downstream riprap lining (see the Study Area Exhibit in the map pocket). The,total domain of analysis covers 545 feet, so is within the 656 foot maximum reach length specified by SCCWRP. Therefore, a single study reach, labeled Reach 1, was analyzed in this report. INITIAL DESKTOP ANALYSIS After the domain of analysis is established, SCCWRP requires an "initial desktop analysis" that involves office work. The initial desktop analysis establishes the watershed area, mean annual precipitation, valley slope, and valley width. These terms are defined in Form 1, which is included in Appendix A. SCCWRP recommends the use of National Elevation Data (NED) to determine the watershed area, valley slope, and valley width. The NED data is similar to USGS mapping. For this report, USGS mapping was used to determine the watershed area tributary to Reach 1. The watershed area is included on the Watershed Exhibit in Appendix A and covers 25.06 acres (0.0392 square miles). The valley slope of Reach 1 was determined from SANGIS' 2014 2-foot contour interval topographic mapping and the channel as-built. The valley slope is the longitudinal slope of the channel bed along the flow line, so it is determined by dividing the elevation difference within Reach 1 by its flow length. The 2-foot contour topographic mapping and as-built were used because they will provide more precise results than NED data. The valley width is the bottom width of the natural channel. The average valley width within Reach 1 was estimated from the 2-foot contour interval topographic mapping, field observations, and review of aerial photographs. The valley slope and valley width for Reach 1 are summarized in Table 1. Reach 1 Tributary Area, sq. mi. I Valley Slope, m/m I Valley Width, m 0.0392 I 0.0112 I 6.10 Table 1. Summary of Drainage Area, Valley Slope, and Valley Width 4 The mean annual precipitation was obtained from the rain gage closest to the site. This is the Western Regional Climate Center's Oceanside Marina gage (see Appendix A). The average annual rainfall measured at this gage for the period ofrecord from 1909 to 2015 is 10.54 inches. These values were input to a spreadsheet to calculate the simulated peak flow, screening index, and valley width index outlined in Form 1. The input data and results are tabulated in Appendix A. This completes the initial desktop analysis. FIELD SCREENING After the initial desktop analysis is complete, a field assessment must be performed. The field assessment is used to establish a natural channel's vertical and lateral susceptibility to erosion. SCCWRP states that although they are admittedly linked, vertical and lateral susceptibility are assessed separately for several reasons. First, vertical and lateral responses are primarily controlled by different types of resistance, which, when assessed separately, may improve ease of use and lead to increased repeatability compared to an integrated, cross-dimensional assessment. Second, the mechanistic differences between vertical and lateral responses point to different modeling tools and potentially different management strategies. Having separate screening ratings may better direct users and managers to the most appropriate tools for subsequent analyses. The field screening tool uses combinations of decision trees and checklists. Decision trees are typically used when a question can be answered fairly definitively and/or quantitatively (e.g., dso < 16 mm). Checklists are used where answers are relatively qualitative (e.g., the condition of a grade control). Low, medium, high, and very high ratings are applied separately to the vertical and lateral analyses. When the vertical and lateral analyses return divergent values, the most conservative value shall be selected as the flow threshold for the hydromodification analyses. Visual observation reveals that the study reach contains a moderate to densely vegetated channel (see the figures following the report text). The vegetative density extends uniformly across the channel bottom and sides. Due to the vegetative cover, a concrete D-41 energy dissipater at the POC, and lack of significant erosion noted during the site investigation, the vertical and lateral stability was anticipated to have a limited susceptibility to erosion. Vertical Stability The purpose of the vertical stability decision tree (Figure 6-4 in the County of San Diego HMP) is to assess the state of the channel bed with a particular focus on the risk of incision (i.e., down cutting). The decision tree is included in Figure 7. The first step is to assess the channel bed resistance. There are three categories defined as follows: 1. Labile Bed -sand-dominated bed, little resistant substrate. 2. Transitional/Intermediate Bed -bed typically characterized by gravel/small cobble, Intermediate level of resistance of the substrate and uncertain potential for armoring. 5 I I I ,I I I I I I I I I I I I .I I I I I I I I 3. Threshold Bed (Coarse/Annored Bed) -annored with large cobbles or larger bed material or highly-resistant bed substrate (i.e., bedrock). Channel bed resistance is a function of the bed material and vegetation. The figures after this report text contain photographs of the natural channel in Reach 1. A site investigation and the figures indicate that the vegetative cover throughout Reach 1 is mature, dense, and fairly uniform (see Figures 2 through 5). The vegetation in some areas is so dense that the channel was either difficult to access or not possible to access at all unless the vegetation is trimmed. The vegetation consists of a variety of mature grasses, shrubs, and trees. Vegetation prevents bed incision because its root structure binds soil and because the aboveground vegetative growth reduces flow velocities. Table 5~13 from the County of San Diego's Drainage Design Manual outlines maximum pennissible velocities for various channel linings (see Table 5-13 in Appendix B). Maximum permissible velocity is defined in the manual as the velocity below which a channel section will remain stable, i.e., not erode. Table 5-13 indicates that a fully-lined channel with unreinforced vegetation h!}s a maximum permissible velocity of 5 feet per second (fps). Due to the dense cover and mature vegetation, the permissible velocity when erosion can initiate is likely greater than 5 fps in the natural channel. Table 5-13 indicates that 5 fps is equivalent to an unvegetated channel containing cobbles (grain size from 64 to 256 mm) and shingles (rounded cobbles). In comparison, coarse gravel (19 to 75 mm) has a maximum permissible velocity of 4 fps. Based on this information, the uniformly vegetated natural channel in Reach 1 has an equivalent grain size of at least 64 mm, which is comparable to a transitional/intermediate bed. In addition to the material size, there are several factors that establish the erodibility of a channel such as the flow rate (i.e., size of the tributary area), grade controls, channel slope, vegetative cover, channel planform, etc. The Introduction of the SCCWRP Hydromodification Screening Tools: Field Manual identifies several of these factors. When multiple factors influence erodibility, it is appropriate to perform the more detailed SCCWRP analysis, which is to analyze a channel according to SCCWRP's transitional/intermediate bed procedure. This requires the most rigorous steps and will generate the appropriate results given the range of factors that define erodibility. The transitional/ intermediate bed procedure takes into account that bed material may fall within the labile category (the bed material size is used in SCCWRP's Form 3 Figure 4), but other factors may trend towards a less erodible condition. Dr. Eric Stein from SCCWRP, who co-authored the Hydromodification Screening Tools: Field Manual in the Final Hydromodiflcation Management Plan (HMP), indicated that it would be appropriate to analyze channels with multiple factors. that impact erodibility using the transitional/intermediate bed procedure. Consequently, this procedure was used to produce more accurate results for each study reach. Transitional/intermediate beds cover a wide susceptibility/potential response range and need to be assessed in greater detail to develop a weight of evidence for the appropriate screening rating. The three primary risk factors used to assess vertical susceptibility for channels with transitional/intermediate bed materials are: 1. Armoring potential -three states (Checklist 1) 2. Grade control -three states (Checklist 2) 6 3. Proximity to regionally-calibrated incision/braiding threshold (Mobility Index Threshold -Probability Diagram) These three risk factors are assessed using checklists and a diagram (see Appendix B), and the results of each are combined to provide a final vertical susceptibility rating for the intermediate/transitional bed-material group. Each checklist and diagram contains a Category A, B, or C rating. Category A is the most resistant to vertical changes while Category C is the most susceptible. Checklist 1 determines armoring potential of the channel bed. The channel bed along Reach 1 is within category B, which represents intermediate bed material within unknown armoring potential due to a surface veneer and dense vegetation. The soil was probed and penetration was relatively difficult through the underlying layer of the reach. Due to the dense vegetative growth, the armoring potential could have been rated higher, but Category B was conservatively (i.e., more potential for channel incision),chosen. Checklist 2 determines grade control characteristics of the channel bed. For Reach 1 the riprap at the lower end is a grade control. The maximum spacing of the grade control within the reach is equal to the reach length or 545 feet. In comparison, the Sv value for Reach 1 from Appendix A is 0.0112, so the 2/Sv value is 586 feet (2/Sv is converted from meters to feet). Since the grade control spacing is less than the 2/Sv value, Reach 1 is within Category A on Checklist 2. The Screening Index Threshold (Checklist 3) is a probability diagram that depicts the risk of incising or braiding based on the potential stream power of the valley relative to the median particle diameter. The threshold is based on regional data from Dr. Howard Chang of Chang Consultants and others. The probability diagram uses dso as well as the Screening Index value (INDEX) determined in the initial desktop analysis (see Appendix A). The Form 1 results in Appendix A determined an INDEX of 0.0049 for Reach 1. The Screening Index Threshold diagram shows that the probability of incising or braiding is less than 50 percent regardless of dso for an INDEX value of 0.015. Since Reach 1 's Screening Index value is less than all of the 50 percent values, Reach 1 is within Category A. The overall vertical rating is determined from the Checklist 1, Checklist 2, and Mobility Index Threshold results. The scoring is based on the following values: Category A= 3, Category B = 6, Category C = 9 The vertical rating score for each of the twelve reaches is based on these values and the equation: Vertical Rating= [(armoring x grade control)112 x screening index score]112 = [(6 X 3)112 X 3]112 = 3.6 Since the vertical rating is less than 4.5, Reach 1 has a low vertical susceptibility to erosion. 7 :I I I I I I I I I I I I I I I I I I I I Lateral Stability The purpose of the lateral decision tree (Figure 6-5 from County of San Diego HMP included in Figure 8) is to assess the state of the channel banks with a focus on the risk of widening. Channels can widen from either bank failure or through fluvial processes such as chute cutoffs, avulsions, and braiding. Widening through fluvial avulsions/active braiding is a relatively straightforward observation. If braiding is not already occurring, the next logical step is to assess the condition of the banks. Banlcs fail through a variety of mechanisms; however, one of the most important distinctions is whether they fail in mass (as many particles) or by fluvial detachment of individual particles. Although much research is dedicated to the combined effects of weakening, fluvial erosion, and mass failure, SCCWRP found it valuable to segregate bank types based on the inference of the dominant failure mechanism (as the management approach may vary based on the dominant failure mechanism). A decision tree (Form 4 in Appendix B) is used in conducting the lateral susceptibility assessment. Definitions and photographic examples are also provided below for terms used in the lateral susceptibility assessment. The first step in the decision tree is to determine if lateral adjustments are occurring. The adjustments can take the form of extensive mass wasting (greater than 50 percent of the banks are exhibiting planar, slab, or rotational failures and/or scalloping, undermining, and/or tension cracks). The adjustments can also involve extensive fluvial erosion (significant and frequent bank cuts on over 50 percent of the banks). Neither mass wasting nor extensive fluvial erosion was evident within Reach 1 during the field investigation. The banks are intact in the photographs included in the figures. The dense vegetation supports the absence of large lateral adjustments. The next step in the Form 4 decision tree is to assess the consolidation of the bank material. The banks were moderate to well-consolidated. This determination was made because the banks were difficult to penetrate with a probe. In addition, the banks showed limited evidence of crumbling and were composed of well-packed particles. Form 6 (see Appendix B) is used to assess the probability of mass wasting. Form 6 identifies a 10, 50, .and 90 percent probability based on the bank angle and bank height. The 2-foot contour interval topographic mapping and as-built plan indicates that the average natural bank angle is 2 to 1 (horizontal to vertical) or 26.6 degrees in Reach 1. Form 6 shows that the probability of mass wasting and bank failure has less than 10 percent risk for a 26.6 degree bank angle or less regardless of the bank height. The final two steps in the Form 4 decision tree are based on the braiding risk determined from the vertical rating as well as the Valley Width Index (VWI) calculated in Appendix A. If the vertical rating is high, the braiding risk is considered to be greater than SO percent. Excessive braiding can lead to lateral bank failure. For Reach 1, the vertical rating is low, so the braiding risk is less than 50 percent. Furthermore, a VWI greater than 2 represents channels unconfined by bedrock or hillslope and, hence, subject to lateral migration. The VWI calculation in the spreadsheet in Appendix A show that the VWI for Reach 1 is 1.81, so is less than 2. From the above steps, the lateral susceptibility rating is low for Reach 1 (red circles are included on the Form 4: Lateral Susceptibility Field Sheet decision tree in Appendix B showing the 8 decision path). A review of aerial photographs confirms a lack of braiding or lateral migration throughout the natural channel. CONCLUSION The SCCWRP channel screening tools were used to assess the downstream channel susceptibility for the Legoland Parking Structure project being designed by Nasland Engineering. The project runoff will ultimately be collected by an existing storm drain system that outlets into an unnamed natural channel along the south side of Palomar Airport Road just west of Hidden Valley Road. The outlet is the point of compliance for the project. The unnamed natural channel was assessed from the POC to the existing riprap channel lining at the confluence with Encinas Creek. The assessment was performed based on office analyses and field work. The results indicate a low susceptibility for vertical and lateral channel erosion for the study reach. The HMP requires that these resllllts be compared with the critical flow calculator results outlined in the County of San Diego HMP. The critical flow calculator results are included in Appendix B for Reach 1 using the spreadsheet provided by the County. The channel dimensions were estimated from the topographic mapping. Based on these values, the critical flow results returned a low threshold. Therefore, the SCCWRP analyses and critical flow calculator demonstrate that the project can be designed assuming a low susceptibility to erosion, i.e., 0.5Q2. 9 I ·I I I I I I I I I I I I I I I I I ·1 I 1: I I. .'lj..' .•. Figure 1. Concrete D-41 Energy Dissipater at Point of Compliance Ir I I I .I I. I :I ·-. I Figure 2. Looking Downstream at Reach 1 from Upper End at POC I I. Figure 3. Looking Upstream at Reach 1 from Middle of Reach Figure 4. Looking Downstream at Reach 1 from Middle of Reach 11 I I ,, I ,, I .I I I ·1, I I ti ,1 I I I I .I I I I I ,, I I ~, I :1 I I I ,, 'I .I ,I ,. I Figure 5. Looking Upstream at Reach 1 from Lower End Figure 6. Rip rap at Lower End of Reach 1 12 LABILE BED • Sand-domlne.led •d,;o< 16mm : •. . • ._% .ii\iif1ic~ li.eril:i,, 25% .. ~,½iiiti~~J;;:,~it'.-;; l;XAMINE RISK FACTORS ,, grade oon trol . • . • ·.: ,_-· -1 armotin9 pglenliSi. • . '. ~":": -: ... • ; -~ p.tixlniity'io'focisf.ii'ilhte:!i!iild ,.. • • : :;-.:.. .: ... • _ '.t\••_h: /~H~~~~J.~_~ .. 12 COARSE/ARMORED BED •dso > f28mM. • Boulcler J large cobble . • ~~~lt~kl,d :::· ·: •. :· : .::·i:If S.ii;~;iif go to bed etodibllity checklists and Incision diagram oheok list Fdl ,gut SOOWRP~ ctftorla 10 determine If the . • •• • r~i;elvlng ~l:1Jlllne! h~·a'l-if~H. ,: ~EDIUl1t, "i)r\QW 1!\lll.~~~ll>il!ly:j •: ••. : •••. :_: 1-i.~~".1 .. ;:,,·.,::..,.~:•.,.;~;;::.;".::a~ Figure 6-4. SCCWRP Verti~af SusceptlbilftJt Figure 7. SCCWRP Vertical Channel Susceptibility Matrix 13 I I I I I I I I I I I I I I 1. I 1,/ I I I I 11 I I I I I I I I. I I I .1) liluiU!aod of tMkfolluro b) P"Qlllml1110 br.sidin{J ~ • 'Filly Slll!Ofl!d 1 l'Ed!OCl bHDk NO &tabl~zeAcn In L'l)lld OO'ldlori • m e-ndllrica t-'i:hula •• ~-: • • ~~11ton {;iyi(l&~~i!.: .. Modar.it~I)' 6/ _Y1dl,~Jlslll.kln1c'f • YliS .. . . . ,. , .. IMSi WA!lTltlG OR ,...v ... e:s ... • --"11-t EX;JEt{SflJI: F.LINl!\L -· .SM$.l\'lN.OI\ C.~TI; __ :. ClJT~lfQ~ .. !tr' NO tlane, ar n,,;,1 crdy lml11d lo . . . b&m1e 111Y.100I\Sl11~cm , ; , AU 1:!ANK 8TRAT4 CON-S-OUOJ\li:D 1111e1-.µg!i~~ <: Ccarse./ 11!5il,t,,il ["'1, d -> .41~ ll)hl_: -~ . ',• ~ .1·.·•.,:. ~;.::- ND f',(18 unmno!ihA..;I MID VVII! S 2 • . .:; .. -_,/i~;,i.i\:.1{~ Fin& ur,;:~mialidlih:d Al6J V'NI >-2 . ,·. --~·.t">~:-:·:;_:_'}·i_ Figure 6-,6, Lateral Channel Susceptibility Figure 8 .. SCCWRP Lateral Channel Susceptibility Matrix 14 I I APPENDIX A I SCCWRP INITIAL DESKTOP ANALYSIS I I I I I I 1- 1 I "' I I I I I I I I I I I I I I I I I FORM 1: INITIAL DESKTOP ANALYSIS Complete all shaded sections. IF required at multiple locations, circle one of the following site types: Applicant Site I Upstream Extent/ Downstream Extent Location: Latitude: ::\f-33_.1·230Y:".:a\::(.~>':·:'~/ Longitude: ;::7_;;f1'ti3069 _,:_·rt::!\)\.\.· ·j ...: ... { .-: :· .. i' -· .::>.;. 1'-. ~ ··.-. i _.~_ • .-•• ," •• ,-:· ... ~. ·····'. ,;;:: -'.:--i ··' -~·-.:: •. -.•: , •• 1 .. !, .. :·.•.:.'.j ,:,. Description (river name, crossing streets, etc.): ·Legoland Rarkmg Structure 2 .. \,:::•'•'..' •. '-.::,,: ::(~}_;}:\ )t. (:)?:~:· ~~::t~~\l. f:/:_::1-t:.\ :,'/;·.~ . .-:~_\/:·.~;)!: _1;·\i-r~-_/ ;: -~r::.!; :·:~//_\= ?:)~(::t\t~};:/./_'.:~: \::··\'.~;,::.??t-::::\;~:i'.t(~t\~-~r;:·~r .\--~, GIS Parameters: The International System of Units (SI) Is used throughout the assessment as the field standard and for consistency with the broader scientific community. However, as the singular exception, US Customary units are used for contributing drainage area (A) and mean annual precipitation (P) to apply regional flow equations after the USGS. See SCCWRP Technlcal Report 607 for example measurements and "Screening Tool Data Entry.xis" for automated calculations. • Form 1 Table 1. Initial desktop analysls in GIS. Symbol Variable Description and Source Value ................. A •.: :.·: .• Area Contributing drainage area to screening location via published -c rn j (mi2) Hydrologic Unit Codes (HUCs) and/or~ 30 m National Elevation Data ~ ~ § (NED), USGS seamless server .. ·':••.;:· ·. • :"/\ :-__:; }·~-= ... ~~~-------------------------------~---2! O.,!/! p me C: s: 0. C: !:!!. Mean annual precipitation (in) Area-weighted annual precipitation via USGS delineated polygons using • • -' , •. : • records from 1900 to 1960 (which was more significant In hydrologic /See.attached models than polygons delineated from shorter record lengths) :_:lqri\j'j table Valley slope Valley slope at site via NED, measured over a relatively homogenous ·_\qn_.tjext page (m/m) valley segment as dictated by hlllslope configuration, tributary '\fofcafoulated confluences, etc., over a distance of up to -500 m or 10% of the main--\J~l(f~s for study -· ····-... --~~a~-~~l_l~n-~~~~~o~_s_i~-t~~r~~n8.~_e __ ~~~d~----------"" ................ --~:r$;th:·· Valley width (m) Valley bottom width at site between natural valley walls as dictated by clear breaks In hills lope on NED raster, Irrespective of potential armoring from floodplain encroachment, levees, etc. (imprecise measurements have negligible effect on rating In wide valleys where VWI Is» 2, as defined In lateral decision tree) .. : •::,'•,• -------·---------------------------- Form 1 Tabl e 2. Simplif ied peak flow, screening index, and valley width index. Values for this table should be calculated In the sequence shown in this table, using values from Form 1 Table 1. Symbol Dependent Variable Equation Q1ocrs 10-yr peak flow (ft3/s) 010G1s = 18.2 * A o.81 * p o.11 Q10 10-yr peak flow (m3/s) 010 = 0.0283 • 01ocra INDEX 10-yr screening Index (m1•6/s0•5) INDEX = Sv*010 0.5 Wrer Reference width (m) Wrer = 6.99 * 010 0,438 VWI Valley width Index (m/m) VWI =WJWrer (Sheet 1 .of 1) B-3 Required Units A (mi2) P (In) 010ds (ft3/s) Sv (m/m) 010 (m3/s) 010 (m3/s) Wv(m) Wrer (m) Value $£1~i~~d Fofrn :·1 /table :·-.,.,·.:-:•r.-.i. ;·:\ ·•:-';-~·~:.,·~ ;.;on,)t~?~t_,p.~ge :fof iq~!¢.µ!ated ,-\j~Jµ~~Jor, ,~tudy :_~~,:?-~-~-\///: := SCCWRP FORM 1 ANAL VSES Reach 1 Reach 1 Area A,sq.ml. 0.0392 Mean Annual Preclp. P, Inches 10.54 10-Year Screening Index INDEX 0.0049 Valley Slope Sv,m/m 0.0112 Reference Width Wref,m 3.37 Valley Width Wv,m 6.10 Valley Width Index VWl,m/m 1.81 10-Year Flow Ql0cfs, cfs 7 10-Year Flow Ql0,cms 0.19 I I I I I I I I I I I I I I I I I I I I US COOP Station Map I I I I I _I Oceanside Marina Rain Gage Location I_ I I I OCEANSIDE MARINA, CALIFORNIA (046377) Period of Record Monthly Climate Summary Period of Record: 10/01/1909 to 01/20/2015 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec • Annual Average Max. Temperature (F) 63.4 62.9 63.4 64.7 66.2 68.3 71.9 73.6 73.1 71.0 67.9 64.5 67.6 Average Min. Temperature 44.2 45.4 47.S 50.5 54.7 58.3 62.2 63.0 60.8 55.6 48.6 44.4 52.9 (F) Average Total Precipitation· 2.16 2.11 1.64 0.91 0.23 0.08 0.03 0.09 0.22 0.45 1.04 1.57 ·10.54 (in.)' Average Total Snowfall (in.) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 ~ verage Snow Depth (in.) 0 0 0 0 0 0 0 0 0 0 0 0 0 :cent of possible observations for period of record. J.vt:ax. Temp.: 96.4% Min. Temp.: 96.2% Precipitation: 97.1% Snowfall: 97.3% Snow Depth: 97.3% Check Station Metadata or Metadata grn,phics for more detail about data completeness. Western Regional Climate Cente1; wrcc@,dri,edu I :1 I I I I I I I I I I I ·1 I I': I I I I I ·1 11 I I I I I I I I I 1" = 500' ~ 0 500 NOTES: THE WATERSHED AREA TRIBUTARY TO THE STUDY REACH (REACH 1) IS DELINEATED IN BLUE. WATERSHED EXHIBIT I I APPENDIX B I SCCWRP FIELD SCREENING DATA -, I I I I I I :I I I I I I .1 I "' I I I I I I I I I I I I I I I I Chapter 5. Open Channels Table 5-13 Maximum Permissible Velocities for Lined and Unlined Channels Material or Lining Natural and Improved Unlined ·channels Maximum Permissible Average Velocity ... (ft/sec) Rne San«;!, Collqidal ......... · ......... ·····-········ ............ ····················-·· ... • .............. _ .................... 1.50 Sandy Loam, Noncolloidal ...................................................... ·····-············ .......................... 175 Silt Loom, NoncolloidaL ......... ·······························-····· .............................................................. 2.00 Alluvial Silts, Noncoffoidal ······-·····················-·····-·························-· .·····-······························· 2.do Ordinary FilTll Loam ·-····· ••••••••••••••••••••••••••••••••••••• • •••••••••••••••••••••••••••• •• ·····-······························· 2.50 ' Volcanic Ash ... ·········-············-········ ............................................ • _ • ... • ..................... · ............ 2 ·50 ~tiff qay, Ver:-/ yollol(f:a.l.. ........... ······· ......... ~·····-· .••···· .··. ·····•···.····-............... ··-······· ........ ·•·. ~ 75 Alluvial Silts, Collo'dal ································-···· ........................................................................... 3. 75 ShalEts And Ha_rdpans -································--·································-···································· ••• 6.00 Fine .Gravel_ ••••• • --···--························-······-···········-····· • •••• ··········-·······-······························· 2.50 Grade~ Loam To CQbbles When Noncolloidal ································-······-······························· 3.75 G11:1ded Sills To Cut,bles WI 1e11 Culloillul... •.•• -······················-··-····-·······-······························· 4.00 t~~:~~,~u~r~li .. ~9\1£9~~~,.~~·'. ~,?·~~·:~'·:::?7t•,7 ~:~:,~:"' .. ,:-~·.··············:~······-~··_-·········:·····~··········· j;Q~ Gobb,lls Arid Shingles ••••••••••••• -••••••••• --·····-······-··························-·····--···········-···················· ~.00 Sandy Silt ·-········-···-········-························~··············-·················-······-·······-······················ 2.00 Silty Clay···········--················································-··························-··················-···················· 2.50 Clay.·-·······-·················································-········.·· .. ····························-······························· 6.00 Poor Sedimentary Rock ................................................................. · .................. · ......................... ·1 0 .0 f.W1~=H~,~~.<;;.~~P!'.~1-J.. . · · · . ,... · . · · ; ·,· .. Unreinforced V~getaflon .... : ...... : .... , .. ,. ~~: .... ~ .. , ...... .-.......... , .... ; ... ~ .. ::. ... :"···········"·····--···· ... , .. : ........ : 5,0 Reinfor~ed Turf ·········-································-······•·················--······-·· ····-···••.•························ ·10.0 Loose Rjprap ···············································-··········· .. ······················-··························Per Table 5·2 Grou.ted Riprap ··············-········································· •.........•...................................................... 2t;;.O Gat!ions ····•················-································ ............ _ ............... • ............................................... '15.0 Soil C~m8nl ...................................................................................... -· ....................................... ·1s.o Concrete ......................................................... · ·····-··················· ................................................. 35.0 • Maximum peimlsslble vetocny listed here Is basic guldellne; hlg11et design velodtles may be used, provided appropriate tecl1n/cal documenrat/o.1 from manllfacturer. Son Diego County Drainage Design Manual July 2005 Page 5.43 a X D Form 3 Support Materials Form 3 Checklists 1 and 2, along with Information recording In Form 3 Table 1, are Intended to support the decisions pathways Illustrated In Form 3 Overall Vertical Rating for Intermediate/Transitional Bed. A B C Form 3 Checklist 1: Armoring Potential A mix of coarse gravels and cobbles that are tightly packed with <5% surface material of diameter <2 mm Intermediate to A and C or hardpan of unknown resistance, spatial extent (longitudinal and depth), or unknown armoring potential due to surface veneer cove ring gravel or coarser layer encountered with probe Gravels/cobbles that are loosely packed or >25% surface material of diameter <2 mm Form 3 Figure 2. Armoring potential photographic supplement for assessing intermediate beds (16 < d5o < 128 mm) to be used In conjunction with Form 3 Checklist 1. (Sheet 2 of 4) REACH 1 RESULTS B-7 X A 0 B 0 C Form 3 Checklist 2: Grade Control Grade control is present with spacing <50 m or 2/Sv m • No evidence of failure/ineffectiveness, e.g., no headcutting (>30 cm), no active mass wasting (analyst cannot say grade control sufficient if mass- wasting checklist Indicates presence of bank failure), no exposed bridge pilings, no culverts/structures undermined • Hard points in serviceable condition at decadal time scale, e.g., no apparent undermining, flanking, failing grout • If geologic grade control, rock should be resistant igneous and/or metamorphic; For sedimentary/hardpan to be classified as 'grade control', It should be of demonstrable strength as indicated by field testing such · as hammer test/borings and/or inspected by appropriate stakeholder Intermediate to A and C -artificial or geologic grade control present but spaced 2/Sv m to 4/Sv m or potential evidence of failure or hardpan of uncertain resistance Grade control absent, spaced >100 m or >4/Sv m, or clear evidence of ineffectiveness Form 3 Figure 3. Grade-control (condition) photographic supplement for assessing intermediate beds (16 < d50 < 128 mm) to be used in conjunction with Form 3 Checklist 2. (Sheet 3 of 4) REACH 1 RESULTS B-8 Regionally-Calibrated Screening Index Threshold for Incising/Braiding For transitional bed channels (d50 between 16 and 128 mm) or labile beds (channel not incised past critical bank height), use Form 3 Figure 3 to determine Screening Index Score and complete Form 3 Table 1. I I I 0.001 ' •,''"I . " .... \ 0.1 1 dso(mm) 10 ♦ stable >< Braided ·• 10% risk --50% risk 1 • • --· X 100 + k1clslng ····· 90% risk :::: GIS-derive.d: 10-yr flow & voll • .ey slope :-, Field-derived: d50 ( 1 00-pebble count) . . 128 0.1 45 C 98 0.125 0 'iii II) E 80 0.114 i~ 64 0.101 0:: .... u N 48 0.087 ~ I 'Cl 32 0.070 ..s Form 3 Figure 4. Probability of Incising/braiding based on logistic regression of Screening Index and d50 to be used in conjunction with Form 3 Table 1. Form 3 Table 1. Values for Screening Index Threshold (probability of incising/braiding) to be used in conjunction with Form 3 Figure 4 (above) to complete Form 3 Overall Vertical Rating for Intermediate/Transitional Bed (below).. Screening Index Score: A= <50% probabUity of Incision for current 0 10, valley slope, and d50; B = Hardpan/d50 Indeterminate; and C = ~50% probability of incising/braiding for current 010, valley slope, and d5o, d5o (mm) FromForm2 Sv*Q100.s (m1.s,so.s) From Form 1 S/Q10 o.s (m 1.5,s0.5) 50% risk of Incising/braiding from table in Form 3 Figure 3 above Screening Index Score (A, B, C) Overall Vertical Rating for Intermediate/Transitional Bed Calculate the overall Vertical Rating for Transitional Bed channels using the formula below. Numeric values for responses to Form 3 Checklists and Table 1 as follows: A= 3, B = 6, C = 9. Vertica.l Ratin9 = {(✓ctrt11ot·lt19 * grade control)* screening index score} 6 X 3 X 3 = 3.6 Vertical Susceptibility based on Vertical Rating: <4.5 = LOW; 4.5 to 7 = MEDIUM; and >7 = HIGH. (Sheet 4 of 4) REACH 1 RESULTS B-9 FORM 4: LATERAL SUSCEPTIBIL TY FIELD SHEET Circle appropriate nodes/pathway for proposed site OR use sequence of questions provided In Form 5. (Sheet 1 of 1) REACH 1 RESULTS B • 10 FORM 6: PROBABILITY OF MASS WASTING BANK FAILURE If mass wasting Is not currently extensive and the banks are moderately-to well-consolidated, measure bank height and angle at several locations (i.e., at least three locations that capture the range of conditions present in the study reach) to estimate representative values for the reach. Use Form 6 Figure 1 below to determine If risk of bank failure is >10% and complete Form 6 Table 1. Support your results with photographs that include a protractor/rod/tape/person for scale. Bank Angle (degrees) (from Field) Bank Height (m) (from Field) Left Bank <26.6 de rees· 2:1} Right Bank >26.6 degrees (2 : 1) Corresponding Bank Height for 10% Risk of Mass Wasting (m) (from Form 6 Figure 1 below) 0 Stable • ., •• 10% Risk -50% Risk -··· • 90% Risk 35 :h 40 \ X 45 )( X ·50 )( ..-. ! \ X 55 E J ~ ' .., 1° d \ 60 fo 2 ~d)@ ~ ·X X 65 ·a:; " :::i:: )( ..lo:: • 00 0 ·>tx x>< X 70 C: 000 () ·~ ~-·--~ ~ )( 1 -oo'bo 6''·• ........ X oi o 0 ~ ~co~ ,o 00 0 30 40 50 60 Bank Failure Risk (<10% Risk) (>10% Risk) 4,7 3.7 1.1 1,5 1.1 0,85 0.66 0,52 0,34 Form 6 Figure 1. Probability Mass Wasting diagram, Bank Angle:HeighU% Risk table, and Band Height:Angle schematic. (Sheet 1 of 1) REACH 1 RESULTS B-12 Critical Flow Calculator enter all values In green cells and drop down boxes Inputs a) Receiving channel width at top of bank {ft) -see figure on right b) Channel width at bed (ft) c) Bank height at top of bank (ft) Channel gradient (ft/ft) Receiving channel roughness Channel materials (use weakest of bed or banks). If materials are varied use weakest material covering more than 20% of channel. Select method of calculating 02 Receiving water watershed annual preclp (Inches) Project watershed annual precipitation (inches) Reach 1 CTj 1~· T I 20.01 IC ~ . ( ) I _:.·5.o1 b 10.01121 ._ ________________ __. Light brush and trees, leaves not present n=0.06 unconsolidated sandy loam 0.035 lb/sq ft alluvial silt (non coloidal) 0.045 lb/sq ft medium Arave! 0.12 lb/sq ft alluvial silVclay 0.26 lb/sq rt 2. 5 inch cobble 1.1 lb/sq ft enter own dS0 (variable) ve etation bed and banks 0.6 lb/s ft Input own Q2 Calculate Q2 usin USGS re ression 110.54_1 Receiving water watershed area at Poe (sq ml) 110,541 Project watershed area draining to PoC (sq ml) ... I ._ .. : .. :. -~-03~21 1 •. -0.03921 Outputs -Flow control range Receiving water 02 Project site Q2 Point of Compliance low flow rate (cfs) Low flow class Channel vulnerablllty 111 • 50' ,-_ I 0 50 STUDY AREA EXHIBIT LEGOLAND PARKING STRUCTURE NOm L =~":tc-::t-:l"~~crs::41 .. O[l)l Na.II to .tr.l'f ,1UU (A ..,,__,lL ti """" 1, _.. U0111'1-Cl •~ ._,,.ololf.O l'r ll•• ~9""Ll.l(NtMIIIII.U AlUIIJV =---'~~~-=~ flW rllO.Ctl J CO."'-"'--~U.IJA'4Jl\l.11'tD~1K ,,,,,.... SOU"-"Y ff" ClWX. "'"' I' I I I i I I I I I I I I I I I I I :1 I I I I Attachment 2d Flow Control Facility Design (Hydro mod ifi cation Re po rt) Attachment 2d TECHNICAL MEMORANDUM: SWMM Modeling for Hydromodification Compliance of: LEGOLAND REGIONAL BIOFILTRATION, HYDROMODIFICATION AND 100-YEAR DETENTION FACILITY Prepared For: LEGOLAND SDP 15-26 / DWG 498-2C / GR2017-0025 May 25, 2017 (Revised September 29, 2017; December 7, 2017) Prepared by: Luis Pa a, PhD, CPSWQ, T oR, D.WRE. R.C.E. 66377 REC Consultants 2442 Second A venue San Diego, CA 92101 Telephone: (619) 232-9200 I _I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I R·E·C ATTACHMENT 2d: TECHNICAL MEMORANDUM TO: LEGOLAND FROM: Luis Parra, PhD, PE, CPSWQ, ToR, D.WRE. DATE: May 25, 2017 (Revised September 29, 2017; December 7, 2017) RE: Summary of SWMM Modeling for Hydromodification Compliance for LEGOLAND Hotel CA II (LLCH20), Carlsbad, CA. INTRODUCTION This memorandum summarizes the approach used to model the entire LEGOLAND project area including hydromodification compliance required for the following re-development projects within the LEGOLAND property: (1) The LLCH20 Hotel, a proposed re-development of a portion of LEGOLAND parking lot; (2) the LEGOLAND Dark Ride (JD 18) a park attraction/ride re-development; (3) LEGOLAND Parking Modification Phase II, a small 0.14 modification within the existing parking area; and (4) the LEGOLAND Water Park Extension (WP-17), all of them proposed re-development of the LEGOLAND property site in the City of Carlsbad. This report uses the Environmental Protection Agency (EPA) Storm Water Management Model 5.0 (SWMM). SWMM models were prepared for the pre and post-developed conditions at the site in order to determine if the proposed LID biofiltration facility has sufficient volume to meet Order R9-2013-001 requirements of the California Regional Water Quality Control Board San Diego Region (SDRWQCB), as explained in the Final Hydromodification Management Plan (HMP), dated March 2011, prepared for the County of San Diego by Brown and Caldwell. Per agreement with the City of Carlsbad, the entire LEGOLAND area was analyzed because the two (2) existing regional flood control basins in the LEGOLAND property will be transformed into a combined Water Quality -Hydromodification -Flood Control basins. Therefore, it is understood that if such regional basin transformation is undertaken, future developments within the LEGOLAND property will not need to demonstrate hydromodification compliance because they will be covered by this study. In other words, the basin will serve as a Hydromodification Compliance option for all future developments because this analysis will demonstrate that the portion of the property area draining directly to the large biofiltration basins will be in compliance with hydromodification requirements. It has been determined that the proposed facilities have adequate capacity to treat the entire LEGOLAND property including any future re-development provided that the total impervious area of all future re-development does not exceed 72. 77 acres. The model takes into account that out of the 128.30 acres of the LEGOLAND property, 122.784 acres drain to the regional facilities in pre-development conditions (the remaining 5.516 acres drain to the surrounded streets), and only 117.524 acres drain to the regional facilities in post-development conditions because the reduction of 5.26 acres of contributing area corresponds to the area draining to the artificial lake in the park, or to multiple water features (such as pools, rides, etc) within the LEGOLAND park. The model follows also a conservative approach in terms of neglecting the contribution of some HMP BMPs already designed for previous re-development portions of LEGOLAND completed recently (like SDP96-14(G), Waterworks Expansion, a 2.2 acre re-development with its own HMP BMP). LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) In addition, and just to avoid confusion with the future areas covered by this study, it will be demonstrated that the equivalent area modeled herein (78.617 acres of equivalent area) can be made hydromodification-compliant if the biofiltration basins are modified in accordance to the recommendations of this study. SWMM MODEL DEVELOPMENT The SWMM Model already accounts for the entire re-development of the LEGOLAND property, including four (4) LEGOLAND re-development projects that propose the re-development of a portion of the LEGOLAND Park (8.56 acres of a property total of about 128.3 acres) to construct: (a) an Hotel building structure along with its associated parking lot; (b) a Dark Ride (JD-18) attraction consisting of a large building and associated modifications; (c) a small Parking Lot Modification (Phase II); and (d) a water park modification. Two (2) SWMM models were prepared for this study: the first for the pre-developed and the second for the post-developed conditions. The project site drains to one (1) Point of Compliance (POC), POC-1 located on the south end of the project boundary. This report will actually demonstrate hydromodification compliance for the entire parcel as long as the following standards are always met: • The entire equivalent re-developed area in the future (area multiplied by C coefficient) draining to the Regional BMPs shall not exceed 78.617 acres. • The four (4) re-development areas analyzed are currently accounting for only 8.562 acres of total area and 5.846 acres of equivalent area (C = 0.683; therefore, 5.846 = 8.562 • 0.683). • Future new re-development areas should not exceed an equivalent area of 72.771 acres (which is 78.617 -5.846). Therefore, if the total remaining area is to be re-developed (117.524 -8.562 = 108.962 acres) it will not have a final re-development C coefficient larger than 0.668 (72. 771/108.962). In regards to the modeling effort, the SWMM model was used since we have found it to be more comparable to San Diego area watersheds than the alternative San Diego Hydrology Model (SOHM) and also because it is a non-proprietary model approved by the HMP document. For both SWMM models, flow duration curves were prepared to determine if the proposed HMP facilities are sufficient to meet the current HMP requirements. The inputs required to develop SWMM models include rainfall, watershed characteristics, and BMP configurations. The Oceanside gauge from the Project Clean Water website was used for this study, since it is the most representative of the project site precipitation due to elevation and proximity to the project site. In regards to evapotranspiration, per the California Irrigation Management Information System "Reference Evaporation Zones" (CIMIS ETo Zone Map), the project site is located within the Zone 4 Evapotranspiration Area. Thus evapotranspiration values for the site were modeled using Zone 4 average monthly values from Table G.1-1 from the City of Carlsbad 2016 BMP Design Manual. The site was modeled with Types A, B and D hydrologic soils as this are the existing soils determined from the NRCS Soil Survey. Soils have been assumed to be compacted in the existing condition to represent the current mass graded and developed condition of the site, and fully compacted in the post developed 2 W.O.7051-01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) conditions. Other SWMM inputs for the subareas are discussed in the appendices to this document, where the selection of the parameters is explained in detail. HMP MODELING EXISTING CONDITIONS In current existing conditions, runoff from the project site discharges to one (1) Point of Compliance (POC) located to the south boundary of the project site. The area tributary to POC-1 consists of the existing theme park which is composed of mechanical rides, walkways, landscape areas, water rides, building structures and associated parking lot. The southern half of LEGOLAND and the roads surrounding the boundary of the park are captured in storm drains and drain into one of two existing flood control facilities located along the southern perimeter of the LEGOLAND site. The flow that makes it into the existing basins is then discharged via existing outlet structures to POC 1. See Table 1 below for a summary of the existing conditions area. It should be clear that no imperviousness has been accounted for, because the new permit does not allow to made hydromodification comparisons for impervious conditions; however, the entire area of the project was included (even areas that currently drain to lagoons and rides) because the pre-park conditions had the entire area draining to POC-1. TABLE 1-SUMMARY OF EXISTING CONDITIONS DMA \ Tributary Area, A Impervious Percentage, POC (Ac) lp(l) DMA-Al 1.644 0% 1 DMA-B1 66.505 0% 1 DMA-Dl 43.07 0% 1 DMA-B2 0.83 0% 1 DMA-D2 10.739 0% 1 TOTAL 122.784 --n/a Notes: (1) -Per the 2013 RWQCB permit, existing condition impervious surfaces are not to be accounted for in existing conditions analysis if they are part of property boundary. The SWMM model was ran using 0.0% impervious for all sub-areas DEVELOPED CONDITIONS Runoff from the existing developed project site (including the proposed four (4) re-development projects) will drain to one of two (2) onsite proposed biofiltration LID BMPs. Once flows are routed via the proposed LID BMPs they are conveyed to POC-1. See Table 2 for a summary of the developed conditions area. As it can be seen the total area in post developed conditions is 5.26 acres less than the area in pre developed conditions. This difference comes from the fact that 5.26 acres from the park will drain into a water ride or are part of a pond, lake or other water body area of the park. Therefore that area will not drain into one of the BMP basins. 3 W.O.7051-01 LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) TABLE 2 -SUMMARY OF DEVELOPED CONDITIONS OMA BMP Tributary Area, A (Ac) (ll lmpeNious Percentage, Ip DMA-Al BMP1 1.64 50.6% DMA-B1 BMP1 64.40 70.2% DMA-Dl BMP1 39.915 74.6% DMA-B2 BMP2 0.83 81.1% DMA-D2 BMP2 10.739 72.0% TOTAL --117.524 -- Notes: (1)-Tributary area includes the area of the LID BMP. Two regional LID biofiltration basins are located within the project site and are responsible for handling hydromodification requirements for the four (4) re-development projects. In developed conditions, the basins will have a surface depth and a riser spillway structure (see dimensions in Table 3). Flows will then discharge from the basins via the outlet stand structures or infiltrate through the amended soil and discharged by low flow orifices. The riser structures will act as spillways such that peak flows can be safely discharged to the receiving storm drain system. Beneath the basins' invert lies the proposed LI[) biofiltration portion of the drainage facilities. As there currently are two existing basins in the LEGOLAND site, in order to minimize grading activities a site specific designed was done for the two basins. A 3 feet deep trench was made in the center of the basins running west to east. This trench was 2 feet wide at the bottom and 5.5 feet wide at the top. In this trench the French drain was place at the bottom and filled with 1.5 feet of pea gravel. On top of the pea gravel 0.5 feet of filter sand were place followed by 1.5 foot of 50% filter sand and 50% existing soil mixed and non-compacted. This design was done to utilize the existing basins without having to do major grading to the basins. As the two basins are currently unlined, no liner is proposed in the trench to allow for infiltration into the underground soil (see Attachment 5 for details ofthe trench). The biofiltration basins were modeled using the biofiltration LID module within SWMM. The biofiltration module can model the amended soil layer, and a surface storage pond up to the elevation of the invert of the first surface discharge. It should be noted that detailed outlet structure location and elevations will be shown on the construction plans based on the recommendations of this study. It should be pointed out that there are other minor facilities in the park that serve water quality and hydromodification purposes, as a consequence of multiple re-development rides in the last years. As those are much smaller than the regional facilities downstream and to simplify the model, those facilities will not be included in the regional analysis. Those facilities represent an additional Safety Factor for hydromodification control and water quality treatment. W.O.7051-01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I LEGOLAND HMP Memo May 25, 2017 {Revised June 21, 2017; September 29, 2017; December 7, 2017) BMP MODELING FOR HMP PURPOSES Modeling of dual purpose Water Quality/HMP BMPs Two LID BMP biofiltration basins are proposed for water quality treatment and hydromodification conformance for the project site. Tables 3 & 4 illustrate the dimensions required for HMP compliance according to the SWMM model that was undertaken for the project. TABLE 3 -SUMMARY OF DEVELOPED DUAL PURPOSE BMP " DIMENSIONS \ . . BMP. Tributary BMP LID Orifice Gravel Depth to Weir Perimeter Total Surface Area (Ac) Area1~1, _#-(in). Depth Primary Riser Length131 (ft) Depth141 (ft) (ftz) (in)(S) Invert (ft)121 . BMPl 206.57 29,826 1-10.0" 24" 3.60' 21.99' 6.0' BMP2 24.27 3,429 1-3.0" • 24" 3.20' 12.57' 5.0' Notes: (1): Area of amended soil= area of the BMP BMP BMP-1 BMP-2 (2): Depth of ponding beneath riser structure's surface spillway, this includes the 3 inches of mulch. (3): Overflow length is the internal perimeter of all riser stand structures. (4): Total surface depth of BMP from top crest elevation to the bottom of the mulch. (5): Gravel depth to be located along the trench where the French Drain will be placed. See Basin detail on attachment 5. TABLE 4 -SUMMARY OF RISER DETAILS: Lower Slot . 18-lnch CMP Riser Primary Weir Secondary Weir Bx h (ft) Elev.111 Perimeter121 I• Elev.111 Perimeter121 Elev.111 Perimeter121 • ;f' ~-(ft) . '. (ft) (ft) • ' (ft) (ft) (ft) • 8.25 X 0.33 2.00 4.71 3.60 21.99 3.60 16 2.00 X 0.33 1.50 n/a n/a 12.57 3.20 12 (1): Elevation 0.00 ft is at the bottom of mulch layer, which is the finish grade. Notes: (2): The perimeter is the circumference for circular risers and for rectangular outlet structures it is the internal perimeter of them. Elev.111 (ft) 4.00 3.75 FLOW DURATION CURVE COMPARISON The Flow Duration Curve (FDC) for the site was compared at the POC by exporting the hourly runoff time series results from SWMM to a spreadsheet. Oi and 01o were determined with a partial duration statistical analysis of the runoff time series in an Excel spreadsheet using· the Cunnane plotting position method {which is the preferred plotting methodology in the HMP Permit). As the SWMM Model includes a statistical analysis based on the Weibull Plotting Position Method, the Weibull Method was also used within the spreadsheet to ensure that the results were similar to those obtained by the SWMM Model. 5 W.O.7051-01 LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) The low flow threshold for hydromodification analysis for this project is 50% of 0 2, based on a study prepared by Chang (2014) in terms of the susceptibility of the receiving creek, were it is demonstrated that the creek has low susceptibility fo_r erosion. Therefore, the range of analysis is 50%02 to 0 10. The range between 50% of 0 2 and 0 10 was divided into 100 equal time intervals; the number of hours that each flow rate was exceeded was counted from the hourly series. Additionally, the intermediate peaks with a return period "i" were obtained (0; with i=3 to 9). For the purpose of the plot, the values were presented as percentage of time exceeded for each flow rate. FDC comparison at the POC is illustrated in Figure 1 in both normal and logarithmic scale. As can be seen in Figure 1, the FDC for the proposed conditions with the HMP BMPs is within 110% of the curve for the existing condition in both peak flows and durations. The additional runoff volume generated from developing the site will be released to the existing point of discharge at a flow rate below the 50% Oi lower threshold for POC-1. Additionally, the project will also not increase peak flow rates between the 0 2 and the 0 10, as shown in the peak flow table in Attachment 1. Discussion of the Manning's coefficient (Pervious Areas) for Pre and Post-Development Conditions Typically the Manning's coefficient is selected as n = 0.10 for pervious areas and n = 0.012 for impervious areas. However, due to the impact that n has in the continuous simulation a more accurate value of the Manning's coefficient has been chosen for pervious areas. Taken into consideration the study prepared by TRWE (Reference [6]) a value of n = 0.05 has been selected (see Table 1 of Reference [6] included in Attachment 7). An average n value between average grass plus pasture (0.04) and dense grass (0.06) has been selected per the reference cited, for light rain (<0.8 in/hr) as more than 99% of the rainfall has been measured with this intensity. SUMMARY This study has demonstrated that the proposed HMP BMPs provided for the LEGOLAND site are sufficient to meet-the current HMP criteria for the entire LEGOLAND property, if the cross-section areas and volumes recommended within this technical memorandum, and the respective orifices and outlet structures are incorporated as specified within the proposed project site. It is assumed that future LEGOLAND re-development (with the property still being a LEGOLAND park) will never exceed the threshold of compliance (which is a total re-development in excess of 72. 771 acres of equivalent area draining to the facilities). 6 W.O.7051-01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) KEY ASSUMPTIONS 1. Type A, B and D Soils are representative of the existing condition site. 2. Both basins will remain unlined to allow underlying soil infiltration, in order to minimize grading of the existing basins. 3. The basins are treating the entire area despite the fact that the four (4) re-development projects occupy an area of only 8.56 acres and use an equivalent area of only 5.846 acres from a total of equivalent area equal to 78.617 acres. Therefore, the design can be seen as a large "hydromodification account" to associate future ire-development projects in LEGOLAND with the hydromodification capacity of the analyzed biofiltration basins. ATTACHMENTS 1. Qi to Q10 Comparison Tables 2. Flow Duration Curve Analysis 3. List of the "n" largest Peaks: Pre-Development and Post-Development Conditions 4. Area Vs Elevation & Discharge Vs Elevation 5. Pre & Post Development Maps, Project Plan and Section Sketches 6. SWMM Input Data in Input Format (Existing and Proposed Models} 7. EPA SWMM Figures and Explanations 8. Soil Maps & Geotechnical Investigation 9. Summary files from the SWMM Model REFERENCES [1] -"Review and Analysis of San Diego County Hydromodification Management Plan (HMP): Assumptions, Criteria, Methods, & Modeling Tools -Prepared for the Cities of San Marcos, Oceanside & Vista", May 2012, TRW Engineering. [2] -"Final Hydromodification Management Plan (HMP) prepared for the County of San Diego", March 2011, Brown and Caldwell. [3] -Order R9-2013-001, California Regional Water Quality Control Board San Diego Region (SDRWQCB}. [4] -"Handbook of Hydrology", David R. Maidment, Editor in Chief. 1992, McGraw Hill.. [S] -"City of Carlsbad BMP Design Manual", February 2016. [6] -"Improving Accuracy in Continuous Hydrologic Modeling: Guidance for Selecting Pervious Overland Flow Manning's n Values in the San Diego Region", TRWE, 2016. 7 W.O.7051-01 LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) LEGOLAND Park -POC 1-Flow Duration Curve 90 ~--·-.·-.· . -.·-•-·-·-·-·-·-·-·-·-·-.---. --·-. -·- -. -·-·-.·-·-·-·-.·-:-·-.·-.·~ 80 ~-=-=::::.:.:::.:: __ :--.:.:::.::::= :::.:.:::.:.:::.:::.::=:=:=:=:=:=:=:=:=:=:=~ ~--·-·-- -·-·---·- -·-·-·-·- -·-·-·-·--·-·-·-·-·-·-·-·-·-·-·-·-·-Cli; ·-·-·-·-·- -·-·-·--·-·-·-·-·-·-·-·-·-·-·-·-·-~ ---·-·--·- - -·- - -- --·-·-·-·-·-·-·-o. 70 Q.·-·-·-·-·-·-·---- Q.·-·-·-·-- -·- -·-·- 60 Qi·-·--- - - - - -·- - - --EKisting --Proposed 50 '--------·-_Ox ___ __,. -Q, 40 30 20 0.0005 90 0.005 Percentage of time ••ceeded (%) LEGOLAND Park -POC 1-Flow Duration Curve 1 -·-·-·-·-·--·-·-·---·-·-·-·-·- -·--·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-Q10 -·-·-·- -·-·-·-·-·-·-·-·-·-·-·-·-·- -·-·-·--·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-1:4 80 ~-=:=:=·=:=::::::.:::.:.:::::.:::.:::::::::::::::::::::.=:=:=:=:=:=:=:=:=:=~ 70 60 50 40 30 20 0.000 ' ·-·-·-·-·-·-·---- --------- --·-·---·-·-·-·-·-·-·-·-·-·-·-·--~ ·-·-·-·-·-·-•-·- - - -·- - - - - -·- -·-·-·-·-·-·-·--·-·-·-·-·-·-·-·-Q,; ·-·-·-·-·-·-·-·-·-·-·-·- - - - --·-·-·-·-·-•-·-·-·-·-·-·-·-·-·-•-·-Q. --Existing --Proposed -·-·Qx ·-. -·-·-· -O:SQ, 0.005 0.010 0.01 5 0.020 Percentage of time e,cceeded (%) 0.025 Figure la and lb. Flow Duration Curve Comparison (logarithmic and normal "x" scale) 8 W.O.7051-01 I I I I I I I I I I I I I I I I I LEGOLAND HMP Memo May 25, 2017 (Revised June 21, 2017; September 29, 2017; December 7, 2017) ATTACHMENT 1 Qz to Q10 Peak Flow Frequency Comparison Table -POC 1 Return Period Existing Condition (cfs) Mitigated Condition (cfs) 2-year 48.784 28.362 3-year 59.577 39.999 4-year 66.887 47.357 5-year 70.298 53.446 6-year 73.477 54.744 7-year 78.035 61.392 8-year 79.615 67.250 9-year 81.866 72.727 10-year 84.301 79.274 9 Reduction, Exist - Mitigated (cfs) 20.421 19.579 19.530 16.852 18.733 16.643 12.365 9.139 5.027 W.O.7051-01 ATTACHMENT 2 FLOW DURATION CURVE ANALYSIS 1) Flow duration curve shall not exceed the existing conditions by more than 10%, neither in peak flow nor duration. The figures on the following pages illustrate that the flow duration curve in post-development conditions after the proposed BMP is below the existing flow duration curve. The flow duration table following the curve shows that if the interval 0.10Q2 -Q10 is divided in 100 sub-intervals, then the post development divided by pre-development durations is never larger than 110% (the permit allows up to 110%). Consequently, the design passes the hydromodification test. It is important to note that the flow duration curve can be expressed in the "x" axis as percentage of time, hours per year, total number of hours, or any other similar time variable. As those variables only differ by a multiplying constant, their plot in logarithmic scale is going to look exactly the same, and compliance can be observed regardless of the variable selected. However, in order to satisfy the City of Carlsbad HMP example, % of time exceeded is the variable of choice in the flow duration curve. The selection of a logarithmic scale in lieu of the normal scale is preferred, as differences between the pre-development and post-development curves can be seen more clearly in the entire range of analysis. Both graphics are presented just to prove the difference. In terms of the "y" axis, the peak flow value is the variable of choice. As an additional analysis performed by REC, not only the range of analysis is clearly depicted (10% of Q2 to Q10) but also all intermediate flows are shown (Q2, Cb, C1i, Os, (4, 01, Os and Qg) in order to demonstrate compliance at any range Ox -Ox+i• It must be pointed out that one of the limitations of both the SWMM and SDHM models is that the intermediate analysis is not performed (to obtain Qi from i = 2 to 10). REC performed the analysis using the Cunnane Plotting position Method (the preferred method in the HMP permit) from the "n" largest independent peak flows obtained from the continuous time series. The largest "n" peak flows are attached in this appendix, as well as the values of Qi with a return period "i", from i=2 to 10. The Qi values are also added into the flow-duration plot. I I I I I I I I I I I I I I I I I I I CJ LEGOLAND Park -POC 1-Flow Duration Curve 90 --r--------------------------------------------- ·-·-·- -·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-Qw ··-. -. -. -. ---. - . -. -. -. - . -. -. -. ----. -. ---. -. -·Q1 + ·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·~ 3 -Existing -Proposed 50 +-------------:---------=='t--------'-----=t-----l ~----·_-_o_x ____ ~-·0.2 ~--·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-· ---, .. + 40 +-----+~~~~-+-------J~ 30 -t-----------:--------,--~-:---:--~--__,,,,,;;;::-----~~-----,-t ~ .S~i -. -. -. -. -. -. -. -. -. -. -. - . -. -. -. -. -. -. -. -. -. -. -. -. -. -. 20 +-------------------------,------------------- 0.0005 0.005 Percentage of time exceeded (%) LEGOLAND Park -POC 1-Flow Duration Curve 90 -,--------------------------------------,------------------- ·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·-·""'Q10 . -. --· -• -. -. - . -·--·--. -. - . - ·---. -~ -. -. -. - . -·· -·-· -· -. -. -. - . - . -~ -• -~9 80 +--...='-ll-=---:-.-=--:-.-;;;;_=-:-.-=--:--:._=-,r==-=.--=-=-=-.-=-=-=-•-=-=-:-.-:;;;;;_:-:-:.-=-.c-==r..--;;_=-:-.-r,;;;_=-:-.-:;;;_::;-:--.-:;;;;;_:-:-:. =-.::.-=-:.--a_=-:-.-:;;_=-:-.-:;;;_=-:--c.-=-:--:. =-:.--;;_=-:-,-:;;_=-:-,-:;;;_::;-:--.=.,-,.=-:--:. =-:.,--;;_;;:-;.-;;;;;;a,.,..=-- 70 60 so 40 30 20 0.000 .. . -. ~. -. -.•. -. -. -. -. -. -. -. -. -. -. -. -. -. -. -· ~. -.' . -. -. -·-. -. ~ 0.005 .. -Existing 3 -Proposed -·-Qx . -. - . - . -. -. --. -. - . - . -. - . -• -. - . -. -. -. - . -. - . -. -. ~2 0.010 0.015 Percentage of time exceeded (%} I t 0.020 0.025 I I Flow Duration Curve Data for LEGOLAND POC-1, City of Carlsbad, CA I I I I I I I I I I I I I I I Q2 = QlO= Step= Count= Interval 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 48.78 cfs 84.30 cfs 0.6051 cfs 499679 hours 57.00 years Existing Condition Q (cfs) Hours> Q %time 24.392 103 2.06E-02 24.997 96 1.92E-02 25.602 93 1.86E-02 26.207 92 1.84E-02 26.812 87 1. 74E-02 27.418 85 1.70E-02 28.023 82 1.64E-02 28.628 81 1.62E-02 29.233 79 1.58E-02 29.838 77 1.54E-02 30.443 75 1.S0E-02 31.048 73 1.46E-02 31.654 69 1.38E-02 32.259 67 1.34E-02 32.864 66 1.32E-02 33.469 60 1.20E-02 34.074 58 1.16E-02 34.679 58 1.16E-02 35.284 56 1.12E-02 35.890 55 1.lOE-02 36.495 54 1.08E-02 37.100 54 1.08E-02 37.705 53 1.06E-02 38.310 51 1.02E-02 38.915 so 1.00E-02 39.520 49 9.81E-03 40.126 47 9.41E-03 40.731 47 9.41E-03 41.336 44 8.81E-03 41.941 43 8.61E-03 42.546 43 8.61E-03 43.151 41 8.21E-03 43.756 40 8.0lE-03 44.362 40 8.0lE-03 44.967 40 8.0lE-03 45.572 39 7.81E-03 46.177 38 7.60E-03 Fraction so% Detention Optimized Hours>Q %time Post/Pre 70 1.40E-02 68% 66 1.32E-02 69% 61 1.22E-02 66% 55 1.lOE-02 60% 51 1.02E-02 59% 49 9.81E-03 58% 48 9.61E-03 59% 44 8.81E-03 54% 41 8.21E-03 52% 38 7.60E-03 49% 37 7.40E-03 49% 36 7.20E-03 49% 33 6.60E-03 48% 32 6.40E-03 48% 30 6.00E-03 45% 29 5.80E-03 48% 26 5.20E-03 45% 26 5.20E-03 45% 25 5.00E-03 45% 25 5.00E-03 45% 25 5.00E-03 46% 25 5.00E-03 46% 25 5.00E-03 47% 25 5.00E-03 49% 25 5.00E-03 50% 25 5.00E-03 51% 23 4.60E-03 49% 22 4.40E-03 47% 21 4.20E-03 48% 21 4.20E-03 49% 21 4.20E-03 49% 20 4.00E-03 49% 20 4.00E-03 50% 19 3.80E-03 48% 19 3.S0E-03 48% 18 3.60E-03 46% 18 3.60E-03 47% Pass or Fail? Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Existing Condition Interval Q(cfs) Hours>Q %time 38 46.782 37 7.40E-03 39 47.387 37 7.40E-03 40 47.992 36 7.20E-03 41 48.598 33 6.60E-03 42 49.203 32 6.40E-03 43 49.808 32 6.40E-03 44 50.413 32 6.40E-03 45 51.018 30 6.00E-03 46 51.623 30 6.00E-03 47 52.229 29 5.80E-03 48 52.834 29 5.80E-03 49 53.439 28 5.60E-03 so 54.044 27 5.40E-03 51 54.649 26 5.20E-03 52 55.254 26 5.20E-03 53 55.859 25 5.00E-03 54 56.465 24 4.80E-03 55 57.070 24 4.80E-03 56 57.675 22 4.40E-03 57 58.280 22 4.40E-03 58 58.885 22 4.40E-03 59 59.490 22 4.40E-03 60 60.095 22 4.40E-03 61 60.701 22 4.40E-03 62 61.306 22 4.40E-03 63 61.911 21 4.20E-03 64 62.516 21 4.20E-03 65 63.121 21 4.20E-03 66 63.726 19 3.80E-03 67 64.331 19 3.80E-03 68 64.937 19 3.80E-03 69 65.542 18 3.60E-03 70 66.147 17 3.40E-03 71 66.752 17 3.40E-03 72 67.357 16 3.20E-03 73 67.962 16 3.20E-03 74 68.567 16 3.20E-03 75 69.173 15 3.00E-03 76 69.778 15 3.00E-03 77 70.383 13 2.60E-03 78 70.988 12 2.40E-03 79 71.593 12 2.40E-03 80 72.198 12 2.40E-03 81 72.803 12 2.40E-03 82 73.409 11 2.20E-03 Detention Optimized Hours>Q %time Post/Pre 17 3.40E-03 46% 17 3.40E-03 46% 17 3.40E-03 47% 17 3.40E-03 52% 17 3.40E-03 53% 16 3.20E-03 50% 16 3.20E-03 50% 14 2.80E-03 47% 14 2.80E-03 47% 14 2.80E-03 48% 14 2.80E-03 48% 12 2.40E-03 43% 11 2.20E-03 41% 10 2.00E-03 38% 10 2.00E-03 38% 10 2.00E-03 40% 10 2.00E-03 42% 10 2.00E-03 42% 10 2.00E-03 45% 10 2.00E-03 45% 10 2.00E-03 45% 9 1.80E-03 41% 9 1.80E-03 41% 9 1.80E-03 41% 9 1.80E-03 41% 9 l.80E-03 43% 9 1.80E-03 43% 9 1.80E-03 43% 9 1.80E-03 47% 9 l.80E-03 47% 8 l.60E-03 42% 8 1.60E-03 44% 8 l.60E-03 47% 8 l.60E-03 47% 8 l.60E-03 50% 8 1.60E-03 50% 8 1.60E-03 50% 8 1.60E-03 53% 8 1.60E-03 53% 8 1.60E-03 62% 7 1.40E-03 58% 7 1.40E-03 58% 7 1.40E-03 58% 7 1.40E-03 58% 7 1.40E-03 64% Pass or Fail? Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass Pass I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Interval 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 Q (cfs) 74.014 74.619 75.224 75.829 76.434 77.040 77.645 78.250 78.855 79.460 80.065 80.670 81.276 81.881 82.486 83.091 83.696 84.301 Existing Condition Detention Optimized Pass or Hours> Q %time Hours>Q %time Post/Pre Fail? 11 2.20E-03 7 1.40E-03 64% Pass 10 2.00E-03 7 l.40E-03 70% Pass 10 2.00E-03 7 1.40E-03 70% Pass 9 l.80E-03 7 l.40E-03 78% Pass 9 l.80E-03 7 1.40E-03 78% Pass 9 l.80E-03 7 1.40E-03 78% Pass 9 l.80E-03 7 1.40E-03 78% Pass 8 l.60E-03 7 1.40E-03 88% Pass 7 1.40E-03 7 1.40E-03 100% Pass 7 l.40E-03 7 l.40E-03 100% Pass 7 l.40E-03 6 l.20E-03 86% Pass 7 1.40E-03 6 l.20E-03 86% Pass 6 l.20E-03 4 8.0lE-04 67% Pass 6 l.20E-03 4 8.0lE-04 67% Pass 6 l.20E-03 4 8.0lE-04 67% Pass 6 l.20E-03 4 8.0lE-04 67% Pass 6 l.20E-03 4 8.0lE-04 67% Pass 6 l.20E-03 4 8.0lE-04 67% Pass Peak Flows calculated with Cunnane Plotting Position Return Period Pre-dev. Q (cfs) Post-Dev. Q Reduction (years) (cfs) (cfs) 10 84.301 79.274 5.027 9 81.866 72.727 9.139 8 79.615 67.250 12.365 7 78.035 61.392 16.643 6 73.477 54.744 18.733 5 70.298 53.446 16.852 4 66.887 47.357 19.530 3 59.577 39.999 19.579 2 48.784 28.362 20.421 ATTACHMENT 3 List of the "n" Largest Peaks: Pre & Post-Developed Conditions Basic Probabilistic Equation: R = 1/P R: Return period (years). P: Probability of a flow to be equaled or exceeded any given year (dimensionless). Cunnane Equation: p = i-0.4 n+0.2 Weibull Equation: p =-i- n+l i: Position of the peak whose probability is desired (sorted from large to small). n: Number of years analyzed. Explanation of Variables for the Tables in this Attachment Peak: Refers to the peak flow at the date given, taken from the continuous simulation hourly results of then year analyzed. Posit: If all peaks are sorted from large to small, the position of the peak in a sorting analysis is included under the variable Posit. Date: Date of the occurrence of the peak at the outlet from the continuous simulation Note: All peaks are not annual maxima; instead they are defined as event maxima, with a threshold to separate peaks of at least 12 hours. In other words, any peak P in a time series is defined as a value where dP/dt = 0, and the peak is the largest value in 25 hours (12 hours before, the hour of occurrence and 12 hours after the occurrence, so it is in essence a daily peak). I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I .I I I List of Peak events and Determination of Q2 and QlO (Pre-Development) LEGOLAND -POC 1 T Cunnane Weibull Peaks Period of Return {Year) {cfs) (cfs) (Years) 10 84.30 88.35 (cfs) Date Posit Weibull Cunnane 9 81.87 83.00 31.6978 12/24/1971 57 1.02 1.01 8 79.61 80.38 32.0053 9/18/1963 56 1.04 1.03 7 78.03 78.30 32.78 3/8/1968 55 1.05 1.05 6 73.48 74.59 32.9976 2/22/1998 54 1.07 1.07 5 70.30 70.44 33.03 12/31/2004 53 1.09 1.09 4 66.89 67.47 33.1208 12/24/1988 52 1.12 1.11 3 59.58 60.07 33.287 1/15/1978 51 1.14 1.13 2 48.78 48.78 33.6115 3/15/1986 so 1.16 1.15 33.6812 1/11/2005 49 1.18 1.18 34.8838 2/22/2008 48 1.21 1.20 Note: 35.2242 1/6/1979 47 1.23 1.23 Cunnane is the preferred 37.5921 2/14/1998 46 1.26 1.25 method by the HMP permit. 37.9038 8/17/1977 45 1.29 1.28 39.0545 2/4/1994 44 1.32 1.31 39.5534 4/27/1960 43 1.35 1.34 39.6177 3/1/1991 42 1.38 1.38 40.774 1/18/1993 41 1.41 1.41 40.784 2/12/1992 40 1.45 1.44 40.842 11/11/1985 39 1.49 1.48 41.8541 12/2/1961 38 1.53 1.52 42.6252 3/11/1995 37 1.57 1.56 43.0817 1/6/2008 36 1.61 1.61 43.3303 2/15/1986 35 1.66 1.65 46.3854 2/17/1998 34 1.71 1.70 47.5504 3/2/1980 33 1.76 1.75 48.1823 1/29/1980 32 1.81 1.81 48.3039 1/16/1978 31 1.87 1.87 48.4913 1/27/2008 30 1.93 1.93 48.7836 12/30/1991 29 2.00 2.00 50.7539 10/20/2004 28 2.07 2.07 50.8105 2/23/1998 27 2.15 2.15 52.0212 2/16/1980 26 2.23 2.23 53.6971 2/27/1983 25 2.32 2.33 54.3663 11/22/1965 24 2.42 2.42 55.4687 1/29/1983 23 2.52 2.53 56.0038 2/3/1998 22 2.64 2.65 57.3863 11/15/1952 21 2.76 2.78 57.6616 2/10/1978 20 2.90 2.92 61.3439 12/19/1970 19 3.05 3.08 63.2771 3/17/1982 18 3.22 3.25 63.5976 1/16/1952 17 3.41 3.45 65.0707 4/1/1958 16 3.63 3.67 66.0513 10/27/2004 15 3.87 3.92 68.9806 1/14/1993 14 4.14 4.21 69.856 2/20/1980 13 4.46 4.54 70.2057 3/1/1978 12 4.83 4.93 70.8265 2/18/2005 11 5.27 5.40 73.2095 10/29/2000 10 5.80 5.96 77.665 2/25/1969 9 6.44 6.65 78.5921 2/4/1958 8 7.25 7.53 81.0542 9/23/1986 7 8.29 8.67 84.8231 2/25/2003 6 9.67 10.21 105.2811 1/4/1995 5 11.60 12.43 109.7477 1/15/1979 4 14.50 15.89 118.6795 1/4/1978 3 19.33 22.00 119.5455 10/1/1983 2 29.00 35,75 132.2883 4/14/2003 1 58.00 95.33 List of Peak events and Determination of Q2 and QlO (Post-Development) LEGOLAND -POC 1 T Cunnane Weibull Period of Return (Year) (cfs) (cfs) Peaks (cfs) (Years) 10 79.27 80.69 Date Posit Weibull Cunnane 9 72.73 75.79 21.7856 2/4/1994 57 1.02 1.01 8 67.25 68.99 21.8053 12/25/1983 56 1.04 1.03 7 61.39 63.09 22.0069 9/18/1963 55 1.05 1.05 6 54.74 55.89 22.1176 12/19/1970 54 1.07 1.07 5 53.45 53.49 22.1694 11/11/1985 53 1.09 1.09 4 47.36 47.99 22.3373 4/27/1960 52 1.12 1.11 3 40.00· 40.00 22.5227 9/5/1978 51 1.14 1.13 2 28.36 28.36 22.6404 3/2/1980 so 1.16 1.15 22.7471 2/2/1960 49 1.18 1.18 23.1377 2/14/1980 48 1.21 1.20 Note: 23.2876 2/13/1954 47 1.23 1.23 Cunnane is the preferred 23.3045 2/26/2004 46 1.26 1.25 method by the HMP permit. 23.6339 1/11/1980 45 1.29 1.28 23.9901 2/23/2005 44 1.32 1.31 24.3086 12/24/1971 43 1.35 1.34 24.409 3/17/1963 42 1.38 1.38 24.4583 9/24/1986 41 1.41 1.41 24.8657 11/22/1996 40 1.45 1.44 25.0248 2/18/1980 39 1.49 1.48 25.4116 2/16/1980 38 1.53 1.52 25.5211 1/15/1978 37 1.57 1.56 25.8589 12/30/1991 36 1.61 1.61 25.8655 1/29/1983 35 1.66 1.65 26.0657 3/1/1983 34 1.71 1.70 26.2425 2/23/1998 33 1.76 1.75 26.5888 12/5/1966 32 1.81 1.81 26.8965 10/29/2000 31 1.87 1.87 28.2393 11/22/1965 30 1.93 1.93 28.3622 1/13/1957 29 2.00 2.00 28.7543 1/9/2005 28 2.07 2.07 29.1101 3/17/1982 27 2.15 2.15 29.7843 1/7/2008 26 2.23 2.23 30.3825 1/16/1972 25 2.32 2.33 32.7493 10/20/2004 24 2.42 2.42 32.7782 2/3/1998 23 2.52 2.53 33.401 2/18/2005 22 2.64 2.65 33.8676 1/20/1962 21 2.76 2.78 39.9793 3/8/1968 20 2.90 2.92 40.0165 2/10/1978 19 3.05 3.08 40.7972 1/6/1979 18 3.22 3.25 42.8945 2/15/1986 17 3.41 3.45 44.311 1/16/1952 16 3.63 3.67 46.4449 2/22/2008 15 3.87 3.92 49.6432 1/16/1978 14 4.14 4.21 50.9757 8/17/1977 13 4.46 4.54 53.4195 1/29/1980 12 4.83 4.93 53.597 2/20/1980 11 5.27 5.40 54.4682 10/27/2004 10 5.80 5.96 59.0605 2/4/1958 9 6.44 6.65 64.9088 3/1/1978 8 7.25 7.53 70.544 2/25/1969 7 8.29 8.67 80.6771 2/25/2003 6 9.67 10.21 80.7287 1/4/1978 5 11.60 12.43 109.0437 ·1/4/1995 4 14.50 15.89 113.3521 1/15/1979 3 19.33 22.00 120.3464 10/1/1983 2 29.00 35.75 133.7446 4/14/2003 1 58.00 95.33 I I I I I I .I I I I I I I I I I I I I I I I I I I I' ATTACHMENT 4 AREA VS ELEVATION The storage provided by the LID BMP is entered into the LID Module within SWMM -please refer to Attachment 7 for further information. Volume provided above the first surface outlet is accounted for in the basin module within SWMM. A stage-storage relationship is provided within this Module, a copy of which is located on the following pages. DISCHARGE VS ELEVATION The orifice has been selected to maximize its size while still restricting flows to conform with the required 10% of the Q2 event flow as mandated in the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. While REC acknowledges that the orifice is small, to increase the size of the outlet would impact the basin's ability to restrict flows beneath the HMP thresholds, thus preventing the BMP from conformance with HMP requirements. In order to further reduce the risk of blockage of the orifices, regular maintenance of the riser and orifice must be performed to ensure potential blockages are minimized. A detail of the orifice and riser structure is provided in Attachment 5 of this memorandum. A stage-discharge relationship is provided on the following pages for the surface outlet structure. The LID low flow orifice discharge relationship is addressed within the LID Module within SWMM -please refer to Attachment 7 for further information. DISCHARGE EQUATIONS 1) Weir: Qw = Cw • L . H3f2 (1) 2) Slot: As an orifice: Q -B • h • c • jzg (H -hs) s-s s B 2 (2.a) As a weir: (2.b) For H > hs slot works as weir until orifice equation provides a smaller discharge. The elevation such that equation (2.a) = equation (2.b) is the elevation at which the behavior changes from weir to orifice. 3) Vertical Orifices As an orifice: Q0 = 0.25 • rrD 2 • c9 • J2g ( H -~) (3.a) I I I I 'I I I As a weir: Critical depth and geometric family of circular sector must be solved to determined Oas a function of I· H: (3.b.l, 3.b.2, 3.b.3, 3.b.4 and 3.b.5) There is a value of H (approximately H = 110% D) from which orifices no longer work as weirs as critical depth is not possible at the entrance of the orifice. This value of H is obtained equaling the discharge using critical equations and equations (3.b). A mathematical model is prepared with the previous equations depending on the type of discharge. The following are the variables used above: Ow, Os, Oo = Discharge of weir, slot or orifice (cfs) Cw, Cg: Coefficients of discharge of weir (typically 3.1) and orifice (0.61 to 0.62) L, 85, D, hs : Length of weir, width of slot, diameter of orifice and height of slot, respectively; (ft) H: Level of water in the pond over the invert of slot, weir or orifice (ft) Aw Tw Yw acr: Critical variables for circular sector: area (sq-ft), top width (ft), critical depth (ft), and angle to the center, respectively. I I I I. I I I I ·I ,, I I I I I I I I I I .I I I I ' ,' I I Outlet structure for Discharge of BMP 1 Discharge vs Elevation Table Low surface orifice 1.000 " Number of orif: 0 Cg-low: 0.61 Middle surface orifice Number of orif: Cg-middle: invert elev: 1" 0 0.61 0.000 ft *Note: h = head above the invert of the lowest surface discharge opening. h* H/D-low H/D-mid Qlow-orif (ft) --(ds) 0.000 0.000 0.000 0.000 0.083 1.000 1.000 0.000 0.167 2,000 2.000 0.000 0.250 3,000 3.000 0.000 0.333 4.000 4.000 0.000 0.417 5.000 5.000 0.000 0.500 6.000 6.000 0.000 0.583 7.000 7.000 0.000 0.667 8.000 8.000-0.000 0.750 9.000 9.000 0,000 0.833 10.000 10.000 0.000 0.917 11.000 11.000 0.000 1.000 12.000 12.000 0.000 1.083 13.000 13.000 0.000 1.167 14.000 14.000 0.000 1.250 15.000 15.000 0.000 1.333 16.000 16.000 0.000 1.417 17.000 17.000 0.000 1.500 18.000 18.000 0.000 1.583 19.000 19.000 0.000 1.667 20.000 20.000 0.000 1.750 21.000 21.000 0.000 1.833 22.000 22.000 0.000 1.917 23.000 23.000 0.000 2.000 24.000 24.000 0.000 2.083 25.000 25.000 0.000 2.167 26.000 26.000 0.000 2.250 27.000 27.000 0.000 2.333 28.000 28.000 0.000 2.417 29.000 29.000 0.000 2.500 30.000 30.000 0.000 2.583 31.000 31.000 0.000 2.667 32.000 32.000 0.000 2.750 33.000 33.000 0.000 2.833 34.000 34.000 0.000 2.917 35.000 35.000 0.000 3.000 36.000 36.000 0.000 3.083 37.000 37.000 0.000 3.167 38.000 38.000 0.000 3.250 39.000 39.000 0.000 3.333 40.000 40.000 0.000 3.417 41.000 41.000 0.000 3.500 42.000 42.000 0.000 3.583 43.000 43.000 0.000 3.667 44.000 44.000 0.000 3.750 45.000 45.000 0.000 3.833 46.000 46.000 0.000 3.917 47.000 47.000 0.000 4.000 48.000 48.000 0.000 Lower Slot Placed on (lb) Number of slots: 1 Invert: 0.00 ft B 8.25 ft hslot 0.333 ft 18-inch CMP Riser (le) Number: 1 Invert: 1.60 ft D: 1.50 ft QI ow-weir Qtot-low Qmid-orif Qmid-weir (els) (cfs) (ds) (els) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0,000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0,000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0,000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Primary Emergency Weir (la) Number of weirs: 1.000 Invert: 1.600 ft B: 21.99 ft Secondary Emergency Weir (lb) Invert: 2.000 ft W: 16.00 ft Qtot-med Qslot-low Ql8" CMP Qpri Qsec Qtot (cfs) (cfs) (cfs) (cfs) (cfs) (cfs) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.615 0,000 0.000 0.000 0.615 0.000 1.740 0,000 0.000 0.000 1.740 0.000 3.197 0,000 0.000 0.000 3.197 0.000 4.922 0.000 0.000 0.000 4.922 0.000 6.730 0.000 0.000 0.000 6.730 0.000 7.772 0.000 0.000 0.000 7.772 0.000 8.689 0.000 0.000 0.000 8.689 0.000 9.518 0.000 0.000 0.000 9.518 0.000 10.281 0.000 0.000 0.000 10.281 0.000 10.991 0.000 0.000 0.000 10.991 0.000 11.657 0.000 0.000 0.000 11.657 0.000 12.288 0.000 0.000 0.000 12.288 0.000 12.888 0.000 0.000 0.000 12.888 0.000 13.461 0.000 0.000 0.000 13.461 0.000 14.010 0.000 0.000 0.000 14.010 0.000 14.539 0.000 0.000 0.000 14.539 0.000 15.049 0.000 0.000 0.000 15.049 0.000 15.543 0.000 0,000 0.000 15.543 0.000 16.021 0.000 0.000 0.000 16.021 0.000 16.486 0.251 1.173 0.000 17.911 0.000 16.938 0.849 3.960 0.000 21.747 0.000 17.378 1.647 7.684 0.000 26.708 0.000 17.807 2.603 12.148 0.000 32.558 0.000 18.226 3.696 17.25 0.000 39.168 0.000 18.635 4.909 22.91 1.193 47.645 0.000 19.036 6.232 29.08 3.375 57.723 0.000 19.429 6.974 35.73 6.200 68.329 0.000 19.813 7.408 42.81 9.546 79.578 0.000 20.191 7.817 50.31 13.340 91.661 0.000 20.561 8.207 58.21 17.536 104.511 0.000 20.925 8.578 66.48 22.098 118.077 0.000 21.283 8.934 75.10 26.999 132.318 0.000 21.635 9.277 84.07 32.216 147.201 0.000 21.981 9.607 93.37 37.732 162.695 0.000 22.322 9.926 103.00 43.531 178.776 0.000 22.658 10.236 112.93 49.600 195.421 0.000 22.988 10.536 123.16 55.927 212.611 0.000 23.314 10.828 133.68 62.503 230.328 0.000 23.636 11.112 144.49 69.318 248.555 0.000 23.953 11.389 155.57 76.364 267.279 0.000 24.266 11.660 166.93 83.634 286.485 0.000 24.576 11.924 178.54 91.121 306.162 0.000 24.881 12.183 190.42 98.819 319.447 0.000 25.182 12.436 202.54 106.722 332.253 0.000 25.480 12.684 214.92 114.826 345.299 0.000 25.775 12.928 227.53 123.124 358.581 0.000 26.066 13.167 240.38 131.614 372.094 0.000 26.354 13.401 253.47 140.290 385.836 Outlet structure for Discharge of BMP 2 Discharge vs Elevation Table Low orifice 1.000" Lower Slot Placed (2b) Number of orif: 0 Number of slots: Cg-low: 0.62 Invert: B Middle orifice 1" hslot Number of orif: 0 Cg-middle: 0.62 Upper slot invert elev: 1.000 ft Number of slots: Invert: *Note: h = head above the invert of the B: lowest surface discharge opening. hslot h* H/0-low H/0-mid Qlow-orif Qlow-weir Qtot-low (ft) --(ds) (els) (cfs) 0.000 0.000 0.000 0.000 0.000 0.000 0.083 1.000 0.000 0.000 0.000 0.000 0.167 2.000 0.000 0.000 0.000 0.000 0.250 3.000 0.000 0.000 0.000 0.000 0.333 4.000 0.000 0.000 0.000 0.000 0.417 5.000 0.000 0.000 0.000 0.000 0.500 6.000 0.000 0.000 0.000 0.000 0.583 7.000 0.000 0.000 0.000 0.000 0.667 8.000 0.000 0.000 0.000 0.000 0.750 9.000 0.000 0.000 0.000 0.000 0.833 10.000 0.000 0.000 0.000 0.000 0.917 11.000 0.000 0.000 0.000 0.000 L000 12.000 0.000 0.000 0.000 0.000 1.083 13.000 1.000 0.000 0.000 0.000 1.167 14.000 2.000· 0.000 0.000 0.000 1.250 15.000 3.000 0.000 0.000 0.000 1.333 16.000 4.000 0.000 0.000 0.000 1.417 17.000 5.000 0.000 0.000 0.000 1.500 18.000 6.000 0.000 0.000 0.000 1.583 19.000 7.000 0.000 0.000 0.000 1.667 20.000 8.000 0.000 0.000 0.000 1.750 21.000 9.000 0.000 0.000 0.000 1.833 22.000 10.000 0.000 0.000 0.000 1.917 23.000 11.000 0.000 0.000 0.000 2.000 24.000 12.000 0.000 0.000 0.000 2.083 25.000 13.000 0.000 0.000 0.000 2.167 26.000 14.000 0.000 0.000 0.000 2.250 27.000 15.000 0.000 0.000 0.000 2.333 28.000 16.000 0.000 0.000 0.000 2.417 29.000 17.000 0.000 0.000 0.000 2.500 30.000 18.000 0.000 0.000 0.000 2.583 31.000 19.000 0.000 0.000 0.000 2.667 32.000 20.000 0.000 0.000 0.000 2.750 33.000 , 21.000 0.000 0.000 0.000 2.833 34.Q00 22.000 0.000 0.000 0.000 2.917 35.000 23.000 0.000 0.000 0.000 3.000 36.000 24.000 0.000 0.000 0.000 3.083 37.000 25.000 0.000 0.000 0.000 3.167 38.000 26.000 0.000 0.000 0.000 3.250 39.000 27.000 0.000 0.000 0.000 3.333 40.000 28.000 0.000 0.000 0.000 3.417 41.000 29.000 0.000 0.000 0.000 3.500 42.000 30.000 0.000 0.000 0.000 1 0.00 ft 2.00 ft 0.333 ft 0 0.00 ft 0.00 ft 0.000 ft Qmid-orif Qmid-weir (ds) (ds) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Qtot-med (cfs) 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 Primary Emergency Weir (2a) Number of weirs:· Invert: B: 1 1. 70 ft 12.57 ft Secondary Emergency Weir (2b) Invert: 2.250 ft W: 12.0 ft Qslot-low Qslot-upp Qweir Qemerg (cfs) (cfs) (cfs) (cfs) 0.000 0.000 0.000 0.000 0.149 0.000 0.000 0.000 0.422 0.000 0.000 0.000 0.775 0.000 0.000 0.000 1.193 0.000 0.000 0.000 1.632 0.000 0.000 0.000 1.884 0.000 0.000 0.000 2.107 0.000 0.000 0.000 2.308 0.000 0.000 0.000 2.493 0.000 0.000 0.000 2.665 0.000 0.000 0.000 2.826 0.000 0.000 0.000 2.979 0.000 0.000 0.000 3.125 0.000 0.000 0.000 3.263 0.000 0.000 0.000 3.397 0.000 0.000 0.000 3.525 0.000 0.000 0.000 3.649 0.000 0.000 0.000 3.768 0.000 0.000 0.000 3.884 0.000 0.000 0.000 3.997 0.000 0.000 0.000 4.106 0.000 0.436 0.000 4.213 0.000 1.897 0.000 4.317 0.000 3.929 0.000 4.419 0.000 6.401 0.000 4.518 0.000 9.246 0.000 4.615 0.000 12.419 0.000 4.710 0.000 15.890 0.000 4.804 0.000 19.635 0.895 4.895 0.000 23.635 2.531 4.985 0.000 27.874 4.650 5.073 0.000 32.341 7.159 5.160 0.000 37.024 10.005 5.245 0.000 41.914 13.152 5.329 0.000 47.001 16.574 5.412 0.000 52.279 20.249 5.493 0.000 57.741 24.162 5.573 0.000 63.381 28.299 5.653 0.000 69.194 32.648 5.730 0.000 75.174 37.200 5.807 0.000 81.317 41.946 5.883 0.000 87.619 46.877 5.958 0.000 94.076 51.989 -I I I I Qtot (cfs) 0.000 0.149 I 0.422 0.775 1.193 1.632 :1 1.884 2.107 2.308 2.493 2.665 2.826 2.979 3.125 3.263 3.397 3.525 3.649 3.768 I 3.884 3.997 4.542 6.110 8.246 10.820 13.764 17.034 I 20.600 25.333 31.061 37.510 I 44.574 52.190 60.311 66.696 72.132 \I 77.750 83.545 89.512 95.645 I 101.940 108.393 114.999 .I I I Stage-Area for Biofiltration BMP Basin 1 Elevation (ft) Area (ft2) Volume (ft3) 0.00 33120 0 Bottom of 3" layer of mulch (ll I 0.25 34952 3403 0.50 36828 12375 0.75 38703 21815 1.00 40468 31711 1.25 42447 42074 1.50 44317 52919 1.75 46185 64231 2.00 48118 76018 Surface Outlet (3) 2.25 49916 88271 2.50 51780 100983 2.75 53642 114160 2.83 54237 118475 3.00 55502 127802 3.25 57361 141910 3.50 59218 156481 3.75 61074 171517 Emergency Weir (4) 4.00 62928 187017 4.25 64780 202980 4.50 66631 219406 4.75 68481 236294 5.00 70329 253645 5.25 72175 271457 5.50 74020 289731 5.75 75863 308466 6.00 77700 327661 !Effective Depth151: 30.58 in At Elevation 2.0 ft is the WQ Area: 29826 (ft2 ---_..._ _______ _ BIOFILTRATION 121 (1): The three inches of mulch begin here, they have a porosity of 0.4 voids. (2): The Water Quality (WQ) area corresponds to the area at 2 feet of the Biofiltration area withouth the Forebay. This is the area corresponding to the ammended soil and gravel. (3): Volume at this elevation coresponds with surface volume for WQ purposes (invert of lowest surface outlet) (4): This elevation corresponds to the top of the riser elevation. (5): Depth to be used in the SWMM LID Controls. See Attachment 7 for more details. Stage-Area for Biofiltration BMP Basin 2 Elevation (ft) Area (ft2) Volume (ft3) 0.00 4104 0 Bottom of 3" layer of mulch (ll I 0.25 4337 422 0.50 4579 1536 0.75 4832 2712 1.00 5101 3954 1.25 5370 5262 1.50 5655 6640 Surface Outlet (ll 1.75 5951 8091 2.00 6255 9617 2.25 6576 11220 2.50 6905 12905 2.75 7245 14674 3.00 7596 16529 3.25 7957 18473 3.50 8329 20508 3.75 8713 22638 Emergency Weir 141 4.00 9107 24866 4.25 9512 27193 4.50 9928 29623 4.75 10355 32158 5.00 10793 34801 23.24 in ~t Elevation 1.50 ft Is the WQ Area: BIOFILTRATION 121 (1): The three in ches of mulch begin here, they have a porosity of 0.4 voids. (2): The Water Quality (WQ) area corresponds to the area at 2 feet of the Biofiltration area withouth the Forebay. This is the area corresponding to the am mended soil and gravel. (3): Volume at this elevation coresponds with surface volume for WQ purposes (invert of lowest surface outlet) (4): This elevation corresponds to the top of the riser elevation. (5): Depth to be used in the SWMM LID Controls. See Attachment 7 for more details. I I I I I I ,. I I ,I I_ 11 I I I 1: ,_ 1• I' - I ATTACHMENT 5 Pre & Post-Developed Maps, Project Plan and Detention Section Sketches I I I I -, I I; ,I 0\ ,. u .,; I :0 :c X w >, 0, 0 0 I -l, >-. I / .!'l :0 :c X I w / ''> 9-u C 0 I 0 "' ., J V) st N / I u a 0 <( / (L ,I ~ I, ro 0 N '-.. U) ::-- I I I co 0 N '-.. !£2_ I i I PLATE -4' x 8" OPENING -2.25' x 4" (NORTH SIDE ORIFICE) BMP-1 76.00 FG • • '½Y«Y«~~'0~~Y«~~~~~ ,"-. ";.,>,,<', ""'-->'>-: '>"'--"''" • ""''0'>-" SEE DETAIL 3 HEREON FOR BMP STRUCTURAL SECTION NORTH SIDE ORIFICE DETAIL FOR BMP-1 NTS NOTE 2' DEPTH IS REPRESENTED BY 30.5" OF EQUIVALENT DEPTH IN THE SWMM MODEL AS THE BMP AREA INCREASES WITH DEPTH. BMP-1 76.00 FG • PLATE -4' x 8" OPENING -2' x 4" (E:AST, SOUTH & WEST SIDE ORIFICE) ~ -:.i- C'>I ' • • EAST, SOUTH & WEST SIDE ORIFICE DETAIL FOR BMP-1 NTS I h A II\ LI X #6 REBAR, SPACED 6" QC AROUND RISER CIRCUMFERENCE TO BE RELOCATED TO PROPOSED RIM ELEV NORTH SIDE ORIFICE EAST SIDE ORIFICE EX RIM ELEV (80.10) EX 84" CMP RISER--------t BMP-1 76.00 FG 84" CMP RISER -ADJUSTED RIM ELEV DETAIL FOR BMP-1 NTS BMP-1 76.00 FG 10" PERFORATED PVC PIPE FL-IN = 72.75 NOTE THE 1 O" PERFORATED PIPE ON BMP DOES NOT REQUIRE A PLATE AS THE ORIFICE DIAMETER NEEDED IS ALSO 10". BOTTOM OF BMP-1 STRUCTURAL SECTION ELEV = 72.50 (SEE DETAIL 3 HEREON FOR BMP STRUCTURAL SECTION DETAIL) ,;, •• ' .. •• D, • _t> t: ' 48"x48" BROOK'S BOX CONNECTION DETAIL FOR BMP-1 NTS SOUTH SIDE ORIFICE 10" STANDARD PVC PIPE FL-IN = 72.75 ~ .E C Q) E C: C'> e C ·s; -~ t5 C: • :::i g> V, ·c: (1) "C G> C: .~ _g CJ) C: LaJ "> c3 ..... I 0.. ~ ca a: 0 LL Cl) ....J u C: en +-' C 0 ~ ::::, (/) C 0 (.) co 0 ~ 0 0:: ~ 0 0) w 0 w a: ::J I-(.) ::J a: 1- (J) 0 z i:: Cl) ~ I= 1-t::l vi Z O <( :5 z () 0 :5 0 fl'\ 0 <( \.J (!) O'.l w UJ (/) ....J _J _J .-~ 1-frl -:, 0 0:: a. SHEET 1 OF 4 SHEETS :I I ·I· I I ., I I I ·I -I I I I ,, I. I I I °' :< 'O ...; :;; :E >< w >-, 0, 0 e 'O >, I / 2 :;; i: X w .:::: '> 0 / 'O C 0 0 CJ> ., .J n <I' N / 1) C, u -,: / 0.: ! ·~ 0 N '-i() '- I 0:, 0 N '-I[) '--.. ; v,, 24"24" BROOKS BOX WITH STEEL COVER 7~~~ '~/;\1/, 10" PVC (STANDARD) @ 1.11% SLOPE TO BMP-1 /. ' ~ ' . • SEE "PLATE DETAIL" ON THE RIGHT 36llx36" BROOK'S BOX CONNECTION DETAIL FOR BMP-2 NTS NOTE 1.5' DEPTH IS REPRESENTED BY 23.24" OF EQUIVALENT DEPTH IN THE SWMM MODEL AS THE BMP AREA INCREASES WITH DEPTH. BMP-2 79.50 FG BMP-2 79.50 FG ORIFICE PLATE MIN. SQUARE DIMENSIONS 1.0 FT GREATER THAN PIPE DIA. HOT-DIP GALVANIZED PLATE AFTER HOLES HAVE BEEN DRILLED (PERFORATED) 3" OPENING PLATE DETAIL NTS NOTE 1. THERE ARE NO PERFORATED PIPES DISCHARGING INTO OUTLET STRUCTURE. 2. PERFORATED PIPES FOR BMP-2 DISCHARGE TO BMP-1 OUTLET STRUCTURE. EX RIM ELEV (83.20) PROPOSED RIM ELEV 82.70 EX 48" CMP RISER·--. A Ill\ Ll_l EX #6 REBAR, SPACED 6" OC AROUND RISER CIRCUMFERENCE TO BE RELOCATED TO PROPOSED RIM ELEV /¾~½~~~-0(~~~"; '" '' "'"" > '>: '0 ,, ' • ' , ':07' BMP STRUCTURAL SECTION BMP-2 79.50 FG 7~¾~¾¾~~-~~y> .. , ,;,,).. ,'),, ,'>, ,'>-":>.:v, '",'' ,, ' .-, ''-/ //" / /7" / / ,, EAST SIDE ORIFICE DETAIL FOR BMP-2 NTS (ONLY IN ONE SIDE) ,/,' :1 'I I 48" CMP RISER -ADJUSTED RIM ELEV DETAIL FOR BMP-2 NTS 110 ;;!:: .. -:I: Cl J, 0 .. w .. Li..iZ S :lo:: W0-1(1)_,.. U 1-l<C <(~W <e.-ucn<o::: :i:::a.. OOcn O U;;J N I 0.. 2 co er: 0 LL CJ) co _J 0 ~ a:: 0 0 D -~ Z D <( w ::5zu 0 w 0 :5 0 er: (9 g ;:li :::J w w (/) _J ...J ...J I-.... ~ u :::J u er: I-CJ) 0 z ~ CJ) ~ F I-u I-u.l w -, w 0 J: 0::: (/) a. SHEET 2 OF 4 SHEETS _,, :I I I I ~, I, I O> ;:: ,:, _,_; t :a :.c )( w >-, 0, 0 e I -g., I / 2 :a :.C X I w ~ ·,: 0 / " C 0 0 I 01 ., ..J "' ~ C'J / " I D " <( / 0.: I ! I o:) 0 N ---..__ -'Q_ ; .. I ..J '.I o:) 0 ~ <O '--.. I ~ I ----------- 0 OSED RIM ELEV 79.60 EX RIM ELEV (76.80) EX 18" CMP RISER! EX #6 REBAR, SPACED 6" OC AROUND RISER CIRCUMFERENCE TO BE RELOCATED TO PROPOSED RIM ELEV i---PROPOSED 18" CMP CONTRACTOR TO WELD PROPOSED 18" CMP TO RIM OF EX 18" CMP RISER BMP-1 I I 76.00 FG ADDITIONAL EX 18" CMP RISER IN BMP-1 ADJUSTED RIM ELEVATION DETAIL NTS .2 C: Q) E C 0) e C ·;;: ·s;.. C: Cl) w i:: . :::, g>(/') ·5; -0 Q) C: -~ ..9 Cl C: w > w _J w 2 0:: 0 w I-C/) 0 ls ::J Zo --:, 0 :5 z <( o::i (9 g 0:: ww w _J ....J C/) .,... 0:: a.. 2 () co ~ >< w ~ I= I-u I-w w --, w 0 :i: a::: (/) a.. SHEET 3 OF 4 SHEETS u C: Cl) -C 0 ±'. :::, (/) C 0 (..) 00 0 0 C\I 0) <( () □- <( Cil Cl) ....J 0:: <( () .I) I I I I ., I, ii I fr I: I ~, I ·1. ·I J I\ I TABULATED DATA FOR BMP-1 & BMP-2 A 18" 8 6" C 18" D 18" E 3" F 24" EX HEADWALL STRUCTURE (SEE PLAN FOR REFERENCE DWG) GABION WALL 3' 6" PVC CLEANOUT CONNECT CLEAN OUT TO 1 O" PVC UNDERDRAIN WITH 1 O"x1 o"x6" PVC WYE f+.-'o,,+--,,\-",-,t-----EX SOIL TO BE MODIFIED. (ENGINEERED) (TILTED & MULCHED) (WITH AN INFILTRATION L-5 IN/HR) PERMEABLE GE OTEX TILE ~~:i!l\\\~ __ ~-----ASTM 33 FILTER SAND EXISTING SOIL IN BASIN //" <Z'/<-.:... / .. "BURRITO WRAPPED" PIPE (SIZE & TYPE PER PLAN) ASTM 8 PEA GRAVEL '-------ASTM 8 PEA GRAVEL PERMEABLE GEOTEXTILE VARIES BIOFIL TRATION FOOTPRINT 5.5' TOP OF FRENCH-DRAIN TRENCH co z .. ... :r. 0 J, .. oz w .. w::c,.. :.:: WO_JO)::,, U t-1< <~w <.-U(l)O::: J:Q.. OOU><o U:J -' ~ w 0 z Cl) <( IIl z 0 I-CIO 0 ~ O il:'.~ 0 O> I-Z O <{ -' ::s Z 0 LL <{ . 0...1 0 0 (9 0 <{ (9 Ill IIl w w (/) ~ -' ...I ...I .... ~ ~ 0 IIl w 0::: 0 LL -' j ~o:: I=~ t; I-w w , W 0 J: 0:: (/) a. I SHEET 4 "BURRITO WRAPPED" PIPE · l ~ (SIZE & TYPE PER PLAN) : OF 4 SHEETS ~L___ _____ __;__ ________ ----i ____ _ I, I· I ,, I ~,! I I -f, /I I_ ,,, ,I- I -,,~ I I ,- ,, ATTACHMENT 6 SWMM Input Data in Input Format (Existing & Proposed Models) [TITLE] [OPTIONS] FLOW UNITS CFS INFILTRATION GREEN AMPT· FLOW ROUTING KINWAVE START DATE 10/01/1951 START TIME 00:00:00 REPORT START DATE 10/01/1951 REPORT START TIME 00:00:00 END DATE 09/30/2008 END TIME 23:00:00 SWEEP START 01/01 SWEEP END 12/31 DRY DAYS 0 REPORT STEP 01:00:00 WET STEP 00:15:00 DRY STEP 04:00:00 ROUTING STEP 0:01:00 ALLOW PONDING NO INERTIAL DAMPING PARTIAL VARIABLE STEP 0.75 LENGTHENING STEP 0 MIN SURFAREA 0 NORMAL FLOW LIMITED BOTH SKIP STEADY STATE NO --FORCE_MAIN_EQUATION H-W LINK OFFSETS DEPTH MIN SLOPE 0 [EVAPORATION] ;;Type Parameters MONTHLY DRY ONLY [RAINGAGES] , , ; ;Name 0.06 NO • ·--------------, , Oceanside [SUBCATCHMENTS] ; i Snow .08 Rain Type --------- INTENSITY 0.11 Time Intrvl 1:00 PRE_DEV 0.15 0.17 0.19 0.19 0.18 0.15 0.12 Snow Data Catch Source ---------- 1.0 TIMESERIES Oceanside Total Pent. Pent. ; ;Name Pack Raingage Outlet Area Imperv Width Slope DMA-Al DMA-Bl DMA-Dl DMA-B2 DMA-D2 [SUBAREAS] ;;Subcatchment • ·-------------- DMA-Al DMA-Bl DMA-Dl DMA-B2 DMA-D2 [ INFILTRATION] ;;Subcatchment • ·--------------, , DMA-Al DMA-Bl DMA-Dl DMA-B2 Oceanside Oceanside Oceanside Oceanside Oceanside N-Imperv ---------- 0.012 0.012 0.012 0.012 0.012 Suction ---------- 1.5 3 9 3 POC-1 POC-1 POC-1 POC-1 POC-1 N-Perv ---------- 0.05 0.05 0.05 0.05 0.05 HydCon ---------- 0.225 0.15 0.01875 0.15 1. 64 0 183 18 66.505 0 5371 1. 7 43.07 0 3722 9 0.83 0 100 1.7 10.739 0 1106 9 S-Imperv S-Perv Pctzero RouteTo ---------- ------------------------------ 0.05 0.1 25 OUTLET 0.05 0.1 25 OUTLET 0.05 0.1 25 OUTLET 0.05 0.1 25 OUTLET 0.05 0.1 25 OUTLET IMDmax ---------- 0.30 0.31 0.33 0.31 0.08 0.06 Curb Length 0 0 0 0 0 PctRouted I I I I I I I I I I I· I I I DMA-D2 [OUTFALLS] ; ;Name . ·--------------'' POC-1 [TIMESERIES] ; ;Name 9 Invert Elev. ---------- 0 Date PRE_DEV 0.01875 0.33 Outfall Stage/Table Type Time Series -------------------------- FREE Time Value • ·--------------------------------------------'' Oceanside [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] FILE "OsideRain.prn• DIMENSIONS -13900. 000 2750 .'000 -5100. 000 8250. 000 Units None [COORDINATES] ; ;Node X-Coord Y-Coord • ·-------------------------------- ------------------' ,-POC-1 [VERTICES] ; ;Link [Polygons] ;;Subcatchment -9500.000 3000.000 X-Coord Y-Coord X-Coord Y-Coord • ·-------------------------------- ------------------'' DMA-Al DMA-Bl DMA-Dl DMA-B2 DMA-D2 [SYMBOLS] ; ;Gage • ·--------------'' Oceanside -13500.000 -11500.000 -9500.000 -7500.000 -5500.000 X-Coord 7000.000 7000.000 7000.000 7000.000 7000.000 Y-Coord -9500.000 8000.000 Tide Gate NO [TITLE) [OPTIONS) FLOW UNITS INFILTRATION FLOW ROUTING START DATE START TIME REPORT START DATE REPORT START TIME END DATE END TIME SWEEP START SWEEP END DRY DAYS REPORT STEP WET STEP DRY STEP ROUTING STEP ALLOW PONDING INERTIAL DAMPING VARIABLE STEP LENGTHENING STEP MIN SURFAREA CFS GREEN AMPT KINWAVE 10/01/1951 00:00:00 10/01/1951 00:00:00 09/30/2008 23:00:00 01/01 12/31 0 01:00:00 00:15:00 04:00:00 0:01:00 NO PARTIAL 0.75 0 0 NORMAL FLOW LIMITED SKIP STEADY STATE BOTH NO - -FORCE_MAIN_EQUATION LINK OFFSETS H-W DEPTH MIN SLOPE [EVAPORATION) ; ;Type MONTHLY DRY ONLY [RAINGAGES] , ' ; ;Name 0 Parameters 0.06 0.08 NO Rain Type . ·-----------------------'' Oceanside INTENSITY [SUBCATCHMENTS) '' ; ;Name Raingage 0.12 Time Intrvl 1:00 • ·------------------------------ DMA-Al Oceanside DMA-Bl Oceanside DMA-Dl Oceanside DMA-B2 Oceanside DMA-D2 Oceanside LID-1 Oceanside LID-2 Oceanside [SUBAREAS] POST_DEV 0.16 0.17 0,19 0.18 0.17 Snow Data Catch Source ---------- 1.0 TIMESERIES Oceanside Total Pent. Outlet Area Imperv -------------------------------- LID-1 1. 54 50.6 LID-1 64.4 70.2 LID-1 39.33 74.6 LID-2 0.83 81.1 LID-2 10.66 72 DIV-1 0.68471 0 DIV-2 0. 07872 0 ;;Subcatchment N-Imperv N-Perv S-Imperv S-Perv PctZero 0.14 0 .11 0.08 0.06 Width -------- 375 6058 3788 275 988 5 5 Pent. Slope Curb Length 5. 3 0 1. 7 0 4. 2 0 1. 7 0 4. 2 0 0 0 0 0 RouteTo PctRouted • ·------------------------ ---------- ---------- -------------------- ----------'' DMA-Al 0.012 0.05 0.05 0.10 25 OUTLET DMA-Bl 0.012 0.05 0.05 0.1 25 OUTLET DMA-Dl 0.012 0.05 0.05 0.1 25 OUTLET DMA-B2 0.012 0.05 0.05 0.1 25 OUTLET DMA-D2 0.012 0.05 0.05 0.1 25 OUTLET LID-1 0.012 0.05 0.05 0.1 25 OUTLET LID-2 0.012 0.05 0.05 0.1 25 OUTLET [ INFILTRATION] ;;Subcatchment Suction HydCon IMDmax • ·---------------------------------- ----------'' DMA-Al 1.5 0.225 0.3 DMA-Bl 3 0.15 0.31 DMA-Dl 9 0.01875 0.33 DMA-B2 3 0.15 0.31 DMA-D2 9 0.01875 0.33 LID-1 9 0.01875 0. 33. LID-2 9 0.01875 0.33 [LID_ CONTROLS] Snow Pack I I I I I I I I I I ,, 1 ,, I I I POST_ DEV , , Type/Layer Parameters .. ----------------------------------, , LID-1 BC LID-1 SURFACE 30.58 0.05 0 0 LID-1 SOIL 18 0.4 0.2 0.1 LID-1 STORAGE 24 0.111 0.02 0 LID-1 DRAIN 1.1163 0.5 0 6 LID-2 BC LID-2 SURFACE 23.24 0.05 0 0 LID-2 SOIL 18 0.4 0.2 0.1 LID-2 STORAGE 24 0 .111 0.02 0 LID-2 DRAIN 9. 7101 0.5 0 6 [LID_USAGE] ;;Subcatchment LID Process Number Area Width 5 2 5 2 InitSatur 5 5 Fromimprv 1.5 1. 5 ToPerv Report File ----------------------------------------- LID-1 LID-1 1 29826 0 LID-2 LID-2 1 3429 0 [OUTFALLS) ii ; ;Name POC-1 [DIVIDERS] ; ;Name DIV-1 DIV-2 [STORAGE) ;; Invert Outfall Stage/Table Elev. Type Time Series ------------------------------------ 0 FREE Invert Diverted Divider Elev. Link Type ------------------------------------ 0 BYPASS-1 CUTOFF 0 BYPASS-2 CUTOFF Invert Max. Init. Storage 0 0 Tide Gate NO Parameters ----------1. 3808 0.1588 curve 100 100 0 0 0 0 0 0 0 0 0 0 ; ;Name Parameters Elev. Depth Depth Curve Params Ponded Evap. Area Frac. Infiltration • ·--------------,, BASIN-1 BASIN-2 [CONDUITS] i; ; ;Name . ·-------------- BYPASS-1 UDRAIN-1 BYPASS-2 UDRAIN-2 [OUTLETS] ; i ; ;Name 0 4. 0 0 3. 5 Inlet Node ---------------- DIV-1 DIV-1 DIV-2 DIV-2 Inlet Node . ·------------------------------,, OUTLET 0 1 BASIN-1 OUTLET-2 BASIN-2 [XSECTIONS) 0 TABULAR 0 TABULAR outlet Node ---------------- BASIN-1 POC-1 BASIN-2 POC-1 Outlet Node ---------------- POC-1 POC-1 BASIN-1 BASIN-2 Length ---------- 10 10 10 10 Outflow Height ---------- 0 0 77700 1 10793 1 Manning Inlet Outlet N Offset Offset ------------------------------ 0.01 0 0 0.01 0 0 0.01 0 0 0.01 0 0 Outlet Qcoeff/ Type QTable ------------------------------- TABULAR/HEAD OUTLET-1 TABULAR/HEAD OUTLET-2 ; ;Link S_hape Geoml Geom2 Geom3 Geom4 Barrels .. --------------------------------------------------------------, , BYPASS-1 DUMMY 0 0 0 UDRAIN-1 DUMMY 0 0 0 BYPASS-2 DUMMY 0 0 0 UDRAIN-2 DUMMY 0 0 0 [LOSSES] ;;Link Inlet Outlet Average Flap Gate ··------------------------------------------------------,, [CURVES] ; ;Name ,,-------------- OUTLET-1 OUTLET-1 OUTLET-1 Type Rating X-Value 0.000 0.083 0.167 Y-Value 0.000 0.615 1.740 -------------------- 0 1 0 1 0 1 0 1 Init. Max. Flow Flow ---------- 0 0 0 0 0 0 0 0 Flap Qexpon Gate ---------- NO NO I POST_DEV OUTLET-1 0.250 3.197 I OUTLET-1 0.333 4.922 OUTLET-1 0.417 6.730 OUTLET-1 0.500 7.772 OUTLET-1 0.583 8.689 OUTLET-1 0.667 9.518 I OUTLET-1 0.750 10.281 OUTLET-1 0.833 10.991 OUTLET-1 0.917 11. 657 OUTLET-1 1. 000 12.288 I OUTLET-1 1.083 12.888 OUTLET-1 1.167 13.461 OUTLET-1 1.250 14.010 OUTLET-1 1. 333 14.539 OUTLET-1 1. 41 7 15.049 ,, OUTLET-1 1. 500 15.543 OUTLET-1 1.583 16.021 OUTLET-1 1. 667 17.911 OUTLET-1 1. 750 21.747 ,t OUTLET-1 1. 833 26.708 OUTLET-1 1.917 32.558 OUTLET-1 2.000 39.168 OUTLET-1 2.083 47.645 OUTLET-1 2.167 57.723 I OUTLET-1 2.250 68.329 OUTLET-1 2.333 79.578 OUTLET-1 2.417 91. 661 OUTLET-1 2.500 104. 511 I OUTLET-1 2.583 118. 077 OUTLET-1 2.667 132.318 OUTLET-1 2.750 147.201 OUTLET-1 2.833 162.695 OUTLET-1 2.917 178.776 'I OUTLET-1 3.000 195.421 OUTLET-1 3.083 212. 611 OUTLET-1 3.167 230.328 OUTLET-1 3.250 248.555 OUTLET-1 3.333 267.279 ,I OUTLET-1 3.417 286.485 OUTLET-1 3.500 306.162 OUTLET-1 3 .. 583 319.447 OUTLET-1 3.667 332.253 I OUTLET-1 3.750 345.299 OUTLET-1 3.833 358.581 OUTLET-1 3.917 372.094 OUTLET-1 4.000 385.836 OUTLET-2 Rating 0.000 0.000 I OUTLET-2 0.083 0.149 OUTLET-2 0.167 0.422 OUTLET-2 0.250 0.775 ,, OUTLET-2 0.333 1.193 OUTLET-2 0.417 1.632 OUTLET-2 0.500 1.884 OUTLET-2 0.583 2.107 OUTLET-2 0.667 2.308 I OUTLET-2 0.750 2. 493 OUTLET-2 0.833 2.665 OUTLET-2 0.917 2.826 OUTLET-·2 1.000 2.979 1~ OUTLET-2 1.083 3.125 OUTLET-2 1.167 3.263 OUTLET-2 1. 250 3.397 OUTLET-2 1. 333 3.525 OUTLET-2 1.417 3.649 ., OUTLET-2 1. 500 3.768 OUTLET-2 1. 583 3.884 OUTLET-2 1.667 3.997 OUTLET-2 1.750 4.542 I OUTLET-2 1.833 6.110 OUTLET-2 1.917 8.246 OUTLET-2 2.000 10.820 OUTLET-2 2.083 13.764 OUTLET-2 2.167 17.034 I/ OUTLET-2 2.250 20.600 OUTLET-2 2.333 25. 3.33 OUTLET-2 2.417 31. 061 'J I I I I I I I I I OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 OUTLET-2 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-1 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 BASIN-2 [TIMESERIES] ; ;Name • ·--------------'' Oceanside [REPORT] INPUT NO CONTROLS NO SUBCATCHMENTS ALL NODES ALL LINKS ALL [TAGS] [MAP] Storage Storage 2.500 2.583 2.667 2.750 2.833 2.917 3.000 3.083 3.167 3.250 3.333 3.417 3.500 0.00 0.25 0.50 0.75 0.83 1.00 1. 25 1. 50 1. 75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 0.00 0.25 0.50 0.75 1.00 1. 25 1. 50 1. 75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 FILE "OsideRain.prn" 37.510 44.574 52.190 60.311 66. 696 72.132 77.750 83.545 89.512 95.645 101.940 108.393 114. 999 48118 49916 51780 53642 54237 55502 57361 59218 61074 62928 64780 66631 68481 70329 72175 74020 75863 77700 5655 5951 6255 6576 6905 7245 7596 7957 8329 8713 9107 9512 9928 10355 10793 DIMENSIONS -5250.000 5798.216 250.000 10237.455 Units None [COORDINATES] ; ;Node I,-------------- POC-1 DIV-1 DIV-2 BASIN-1 BASIN-2 [VERTICES] X-Coord -2500.000 -4000.000 -1000.000 -4000.000 -1000.000 Y-Coord 6000.000 9000.000 9000.000 7000.000 7000.000 POST_DEV ; ; Link X -Coo rd • ·--------------------------------,, [Polygons] ;;Subcatchment X-Coord • ·--------------------------------,, DMA-Al -5000.000 DMA-Bl -4000.000 DMA-D1 -3000.000 DMA-B2 -2000.000 DMA-D2 0.000 LID-1 -4000.000 LID-2 -1000. 000 [SYMBOLS] ; ;Gage X-Coord • ·--------------------------------,, Oceanside -2500.000 Y-Coord Y-Coord 10000.000 10000.000 10000.000 10000.000 10035.671 9500.000 9500.000 Y-Coord 9000.000 POST_DEV ' I I I I I I ·I I I I ,- 1 :1 1: -, ,- 1 ,- ,, -, I :I. 1: ,11 ,, ,, ATTACHMENT 7 EPA SWMM FIGURES AND EXPLANATIONS Per the attached, the reader can see the screens associated with the EPA-SWMM Model in both pre-development and post-development conditions. Each portion, i.e., sub-catchments, outfalls, storage units, weir as a discharge, and outfalls (point of compliance), are also shown. Variables for modeling are associated with typical recommended values by the EPA-SWMM model, typical values found in technical literature (such as Maidment's Handbook of Hydrology). Recommended values for the SWMM model have been attained from the interim Orange County criteria established for their SWMM calibration. Currently, no recommended values have been established by the San Diego County HMP Permit for the SWMM Model. Soil characteristics of the existing soils were determined from the site specific NRCS Web Soil Survey and Geotechnical Investigation (both located in Attachment 8 of this report). Some values incorporated within the SWMM model have been determined from the professional experience of REC using conservative assumptions that have a tendency to increase the size of the needed BMP and also generate a long-term runoff as a percentage of rainfall similar to those measured in gage stations in Southern California by the USGS. A technical document prepared by Tory R Walker Engineering for the Cities of San Marcos, Oceanside and Vista (Reference [1]) can also be consulted for additional information regarding typical values for SWMM parameters. PRE-DEVELOPED CONDITION F ,Q: file £,dit ~ew froject • Report !ools Window Help Auto-length:.□ff .. Offuts:Depth "-:.1 ·-flowunas:CFS ~li11.zoomlevel:100% I X,Y:·12985.84~.8346.680 fl Rain Gage Oc1:ansid~ __ _ _ [ij~1 Property Value Name jOceanside j X-Coordinate • -9500.000 ...... ., ........... • I! Y-Coordinate 8000.000 Description Tag Rain Format INTENSITY Time Interval 1:00 Snow Catch Factor 1.0 Data Source TIMESERIES -File Name -Station ID -Rain Units IN User-assigned name of rain gage , . ------.. ____ • • ____ _J Oceanside • DMA-01 l , , ',\PQC-1 -. Outfall POC-1 Property Value DMA-02 ,II Name ]POC-1 llnll---------_;· ............. _._ ...... _ ...... ! : X-Coordinate -9500.000 ' Y-Coordinate 3000,000 Description Tag Inflows NO Treatment NO Invert El. 0 Tide Gate NO Type FREE User-assigned name of outfall ,1. ? l-71el!ic7 'I .. .I ., ., ., <1£ ,, I I I I I I I I ·-· I II I ,, I I I -, 'I I I ,, I I· :1_ I _I I I nt DMA-Al --- Property Name X-Coordinate Y-Coordinate Description 11 Tag Rain Gage Outlet Area Width % Slope % lmperv N'.lmperv N-Perv D store-I mperv Dstore-Perv %Zero'.lmperv S ubarea Routing Percent Routed Infiltration Groundwater Snow Pack LID Controls Land Uses Initial Buildup Curb Length Average surface slope(%) ----- Infiltration Editor Infiltration Method Property I Suotioo Hood Conductivity Initial Deficit --_,. _____ ... ii] Value I DMA-A1 -13500.000 I 7000.000 ' i 111 11' I I ,, Oceanside POC-1 1.64 183 j1 s:::::::::::::::::::::::::::::·::::::::::::::::::i 0 0.012 0.05 0.05 0.1 25 OUTLET 100 GREEN_AMPT NO 0 0 NONE 0 ------ I I -- :.ubcatchment OMA-Bl lilll _,__..<.,.. ___ -_.,_ Property Value I Name DMA-B1 ; X-Coordinate -11500.000 1, Y-Coordinate 7000.000 Description ,,, Tag ' 11 : I ,, Rain Gage Oceanside ' Outlet POC-1 Area 66.505 Width 5371 % Slope j1.7 ............................................. J % lmperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 I Average surface slope(%)_ ----~-~---~..:.._ -----• --- ii Infiltration • -------~ 11 I! 1,1:0a<;,: Method ,-[ G_R_E_E N-_-:.-~-~T-· _--_--.... --..] j li,....-----------------.1 Property Value i Suctioo H"d Conductivity Initial Deficit Subcatchment DMA-01 iii, . ~---·-.. . ·-. . Property Value I, Name DMA~Dl X-Coordinate -9500.000 Y-Coordinate 7000.000 Description Tag I ' I ' Rain Gage Oceanside Outlet POC-1 Area 43.07 Width 3722 % Slope i9 ! E .............................................. , ...... , •. : % lmperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 D store-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 ; -~ C l~verage surface slope(%) . -- Infiltration Editor Infiltration Method I GREEN_AMPT IIIIP----------,...,..--------.1;! 11 Property Value Suction Head Conductivity Initial Deficit :s I :I , ~: ~: 875 ............... , •• , ............. , .......... , 1~ubcat~:h,;ent OMA-B2 lb .. --• ~-► Property Value I j Name DMA-82 X-Coordinate -7500.000 Ill Y-Coordinate 7000.000 I Description I Tag 1: I' Rain Gage Oceanside Outlet POC-1 Area 0.83 Width 100 % Slope jl .7·····························••.•········_J % lmperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 D store-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 Average surface slope(%) 1 I 11 •• .·. ·,,:., .. ------.. ·-. -__ . ..,. II Infiltration Method "I I GREEN_AMPT 'FI l I . Property Value I I ii I : Suction Head ~:~---------Ji Conductivity Initial Deficit I I I I I I I I I I. .1 1· I :1 I I I I I I: I .I I I- I I Subcatchment DMA-D2 ell ~ ~-·•-·-~-.. ...... _ ...,_ ----·-.. .• I Property Value 1- Name· DMA-02 X-Coordiriate -5500.000 Y-Coordinate 7000.000 Description :ii Tag Ii I Rain Gage Oceanside Outlet POC-1 Area 10.739 Width 1106 -..... ,. .. ~ "")ouuu·••j-.-,-, .. ·,.,··, ............. %Slope is I ; --.,.1 .................... ~ ...... ~--···. -~··---....... = %1mperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100: Infiltration GREEN_AMPT Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 C . l~~~ra_9e s~r~a~e s:pe (%) 'Infi'lt~tion Editor -~-="".:1=--...-...-... 1: ! ! -; . . ---- .......,,_: __ -• -· • ----~ 'I! I Infiltration Method { GREEN_AMPT ,, j 1J '·•! :~ ' ,i Property Value Suction Head i9 i-I Conductivity ·::::875---··1 Initial Deficit POST-DEVELOPED CONDITION ' 9 ~ fifll I 0 'v ' ◊ Ill===· ·=•""=·="'====1° l"1 + --ti • • 21. ~ Outfalls C? ~-~-----~-· !i•lt I@ El 0 T OMA-Al •-. DMA-81 r ·• •. LID-I"' ·r· DIV-1 BASIN-1 DMA-01 DMA-82 -• •. Oceanside ~ UDRAIN-2 DIV-2 DMA-02 -• ·Hlm114Miillil:i!❖H 1 Auto-l.ength:Off • ! Offiet:s: Depth Flow Units:: CFS • Zoom Level: 100%'. j X..Y: -4322.680. 10261.757 -1 Property Value Property Value Name \Oceanside llllt-------------,•=··"0'-'"'-''"-·000--"'"-"''''"'"''_: 111111-N_a_m_e _______ !~~C.:1 __________ ....... _,,, .. _! • X-Coordinate -2500.000 X-Coordinate -2500.000 -~ Y-Coordinate 9000.000 Y-Coordinate 6000.000 Description Description Tag Tag Rain Format INTENSITY Inflows NO Time Interval 1:00 Treatment NO Snow Catch Factor 1.0 Invert El. 0 Data Source TIMES ERIES Tide Gate NO Type FREE • File Name • Station ID • Rain Uni1ts IN User-assigned name of rain gage User-assigned name of outfall I I I I I I I I " I. I ,, I I I I ,-------~ Subcatchment OMA-Al ,_.,,__ Property Value Name DMA-A1 X-Coordinate -5000.000 ! Y '.Coordinate 10000.000 ! Description II Tag Rain Gage Oceanside Outlet LID-1 Area 1.54 Width 375 I % Slope 5.3 % lmperv 50.6 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.10 %Zero'! mperv 25 Subarea Routing OUTLET Percent Routed 100 .······································9:" Infiltration )GREEN_AMPT : ... · .. __ ..... _. __ ............... _ ......... _ .... ___ - Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 - Infiltration parameters (click to edit) ---·--..., __ --- ; Infiltration Editor :l::r:z 1 Infiltration Method I GREEN_AMPT Property Value i ~,o:onH~ uctIvIty .Initial Deficit I Subcatdhment DMA-81 [ii " Property Value I Name DMA-B1 X-Coordinate -4000.000 Y-Coordinate 10000.000 Description i Tag ! I ' Rain Gage Oceanside Outlet LID-1 Area 64.4 Width 6058 % Slope 1.7 % lmperv 70.2 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration jGREEN_AMPT······ XJ Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 --· Infiltration parameters (click to edit) - Infiltration Editor Infiltration Method i, Property Suction Head Conductivity Initial Deficit -- I GREENj1MPT Value I 1 Subcatchment DMA-01 Property Value Name DMA~D1 X-Coordinate -3000.000 Y-Coordinate 10000.000 i ! Description I Tag Rain Gage Oceanside Outlet LID-1 Area 39.33 Width 3788 % Slope 4.2 % lmperv 74.6 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration jGREEN_AMPT_·· __ ___I,,:] Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 Infiltration parameters (click to edit) --- !' Infiltration Editor 11 . --~------~ ri Infiltration Method - [ GREEN_AMPT Property. Value .. . tt • Suction Head ,19 i lt-C-o-nd_u_c-tiv-ity-----1~~: 875""" --'I Initial Deficit ,: Subcat~hment ~(?:!_~~- e• -'""'•••-•-•~---~ '" 'j Property Value I I Name LID-1 X-Coordinate -4000.000 I ! Y-Coordinate 9500.000 i'. Description ll Tag ,. Rain Gage Oceanside Outlet DIV-1 Area 0.68471 Width 5 % Slope 0 % lmperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration jGREEN_AMPT ___ .... 8 Groundwater NO Snow Pack LID Controls 1 Land Uses 0 Initial Buildup NONE Curb Length 0 Infiltration parameters (click to edit) --. -----. : Infiltration Editor Infiltration Method Property Value r Suction Head 'i9 , 111----------.~!•!•n.••.•Y!!'!P'"·,.·'·!"'!!'~'-''''"..!'!."'''""'"·'"·'''.!'"''" Conductivity 0.01875 . Initial Deficit 0.33 I I I I I :1 I I I ;::, I' I I :I I I I I I I I I I I I I I I I I I I -1 I Subcatchment DMA-82 ii] -. --.-·-' . =--- Property Value I Name DMA-B2 X-Coordinate -2000,000 Y-Coordinate 10000.000 Description Tag 'i 1: Rain Gage Oceanside Outlet LID-2 Area 0.83 Width 275 % Slope 1.7 % lmperv 81.1 N-lmperv 0,012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-I mperv 25 S ubarea Routing OUTLET Percent Routed 100 Infiltration ,·-.............. -............ -.. ·-----·~·, jGREEN_AMPT ... · ................ _ ....... _ ........ __ ._._._ - Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 ,. Infiltration parameters (click to edit) -• ---. -,., __ .., --------'-- . ·-. . t1=~=1, Infiltration Editor : ! -----_,,,. __ <.1:L._ ,....,__ ~· .. _.._ -. --_,, ~ ----··- Infiltration Method [ GREEN_AMPT ·] I Property Value I I Suction Head i3 i I Conductivity :: .. --.. ..-. _ ...... I Initial Deficit ii Subcatchment DMA-D2 ~II . Property Value Name DMA-D2 • X-Coordinate 0.000 Y-Coordinate 10035,671 Description Tag I Rain Gage Oceanside Outlet LID-2 Area 10,66 Width 988 % Slope 4.2 % lmperv 72 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration jGREEN_AMPT. __ J .. ·I Groundwater NO Snow Pack LID Controls 0 Land Uses 0 Initial Buildup NONE Curb Length 0 '- Infiltration parameters (click to edit) -·-. 11" Infiltration Method Ii i-----------------1111 I GREEN_,ll.MPT Property • Value • Suction Head :19 i 11-C-o-nd_u_c-tiv-ity-----1!:07s .. , .. .,, -"I Initial Subcatchment UD-2 ~ill -----·------ Property Value Name LID-2 X-Coordinate -1000.000 Y-Coordinate 9500.000 11 Description J: Tag Rain Gage Oceanside Outlet DIV-2 Area 0.07872 Width 5 % Slope 0 % lmperv 0 N-lmperv 0.012 N-Perv 0.05 D store-I mperv 0.05 Dstore-Perv 0.1 %Zero-lmperv 25 Subarea Routing OUTLET Percent Routed 100 Infiltration ,--....... --..................... -....... -□_-- IGREEN_AMPT l ... .. __ ....... _._ ... _ ........................... _ . Groundwater NO Snow Pack LID Controls 1 Land Uses 0 Initial Buildup NONE Curb Length 0 .. ------' Infiltration parameters {click to edit) -------- i Infiltration Editor 11 - ----- Ii Infiltration Method --. ~ ------- ";/ :i .iZ.:~ I GREEN_AMPT '( t; I i,----------,----------,,11,l_l Property Value ,, Suction Head J9 ! 1 ----------.... , ............ , .... , ................. , .. ,,, .......... , ..... ,., Conductivity 0. 01875 Initial Deficit. 0.33 I I ., I I I I I I I I I I I I I I I I I I I I I I I I I I_ 1: ,- 1 I EXPLANATION OF SELECTED VARIABLES Sub-Catchment Areas: Please refer to the attached diagrams that indicate the DMA and Bio-Retention BMP (BMP) sub areas modeled within the project site at both the pre and post developed conditions draining to the POC. Parameters for the pre-and post-developed models include soil types A, B and D as determined from the site specific Natural Resources Conservation Service (NRCS) and geologic review (attached at the end of this appendix). Suction head, conductivity and initial deficit corresponds to average values expected for these soils types, according to sources consulted, professional experience, and approximate values obtained by the interim Orange County modeling approach. REC selected infiltration values, such that the percentage of total precipitation that becomes runoff is realistic for the soil types and slightly smaller than measured values for Southern California watersheds. Selection of a Kinematic Approach: As the continuous model is based on hourly rainfall, and the time of concentration for the pre-development and post-development conditions is significantly smaller than 60 minutes, precise routing of the flows through the impervious surfaces, the underdrain pipe system, and the discharge pipe was considered unnecessary. The truncation error of the precipitation into hourly steps is much more significant than the precise routing in a system where the time of concentration is much smaller than 1 hour. Sub-Catchment BMP: The area of bio-filtration must be equal to the area of the development tributary to the bioretention facility (area that drains into the biofiltration, equal external area plus bio-filtration itself). Five (S) decimal places were given regarding the areas of the bio-filtration to insure that the area used by the program for the LID subroutine corresponds exactly with this tributary. Control Name[ _ml ________ _ ·I ! ~ Control Name 1m • I i1 ---------- " I'' Number of Replicate Units I :: [] LID Occupies Full Subcatchment Area of Each Unit (sq ft or sq m) % of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) % Initially Saturated % of Impervious Area Treated '1 I~ 1El 29826 I J 100,0 'o ..... J 0 J . .;100 . '_J C - ., -II !; 11 Number of Replicate Units [cJ LID Occupies Full Subcatchment Area of Each Unit (sq ft or sq m) % of Subcatchment Occupied Top Width of Overland Flow Surface of Each Unit (ft or m) % Initially Saturated % of Impervious Area Treated 3429 J 100.0 0 . --J \.._ .... ,. __ . ~o._· _ __) 20~ ___ ] LID Control Editor Control Name: LID Type: ~'B=io=·=R=et=e=nt=io=n=C=e=ll=--~=~=·~•~J :' Process Layers: Surface j~ . ,Storage~ .:_U_n_cler_drain Storage Depth (in. or mm) Vegetation Vo',ume Fraction Surf ace Roughness (Mannings n) Surface Slope (percent) Control Name: LID Type: Process Layers: l3~.~~----j l9:05 _ ----_] -Surface I S,Jil_. ,I Storage l"' ___ u __ nd_e_!d_ra_in ... ,I ____ ~ Height (in. ormm) Void Ratio (Voids/ Solids) Conductivity (in/hr or mm/hr) Clogging Factor i24 l-__ J t1_11 ____ _J l~~---_j Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. , LID Control Editor Control Name:!.__. _________ __, LID Type: I Bio-Retention Cell • Process Layers: .,Surface JI Soil I, StorageJcUnderdrainl Thickness 18 (in. ormm) Porosity 0.4 [volume fraction) Field Capacity 0.2 [volume fraction) Wilting Point 0.1 [volume fraction) Conductivity 2 (in/hr or mm/hr) Conductivity Slope 5 Suction Head 1.5 (in. ormm) , LID Control Editor ---~{'-;, Control Name:! '--l■_ltl_l _______ _ LID Type: I B io-R Eltentio_n Cell _ Process Layers: Surface I. Soil __ !:Storage_! Underdrain IL__ ___ _ Drain Coefficient (in/hr or mm/hr) Drain Exponent Drain Off set Height (in. or mm) 1.1163 0.5 0 Note: use a Drain Coefficient of 0 if the LID unit has no underdr ain. I I I I I I I I I I -1 I I I I I I I I I I I .I I I I_ I I I 1: I I I Control Name: LID Type:. ---... J Process Layers: Surf ace t Soil . I, Storage I, U ~dercjr ainJ Storage Depth '23.24 I [in. ormm] ... --. . . , Vegetation Volume '0.05 J Fraction Surf ace Roughness 10 . 1 [Mannings n) Surf ace Slope ·O (percent] l . LID Control Editor Control Name: 1m LID Type: [_Bio-Retention Cell ... J Process Layers: ,~urface I Soil 11 Storage I, Underdrainl L-~-.....a.L------, Height ~ (in. or mm] Void Ratio lO~~l ---[\/ oids / Solids] Conductivity 10.02 (in/hr or mm/hr) Clogging Factor ~- Note: use a Conductivity of 0 if the LID unit has an impermeable bottom. J j t ~ io-Retention Ce~ • • ·I Process Layers: ,S_ur~acel Soil t Storage I, Underdrain,I Thickness L1_B_ .J (in. ormm) ------ Porosity ~4 • ' (volume fraction) · ____ J Field Capacity Lo_.2 --_J [volume fraction] Wilting Point [0.:.1_ J [volume fraction] Conductivity G.._ ____ J [in/hr or mm/hr) Conductivity Slope l5 ] Suction Head ,1.5 I (in. ormm) '--.. __ .J LID Control Editor Control Name: 1m LID Type: t Bio-Retention Cell Process Layers: Surface L Soil •I Storage,! Underdrain I L------, Drain Coefficient [in/hr or mm/hr I Drain E Mponent Drain Off set Height [in. or mm) Note: use a Drain Coefficient of 0 if the LID unit has no underdr ain. LID Control Editor: Explanation of Significant Variables Storage Depth: The storage depth variable within the SWMM model is representative of the storage volume provided beneath the first surface riser outlet and the engineered soil and mulch components of the bioretention facility. In those cases where the surface storage has a variable area that is also different to the area of the gravel and amended soil, the SWMM model needs to be calibrated as the LID module will use the storage depth multiplied by the BMP area as the amount of volume stored at the surface. Let ABMP be the area of the BMP (area of amended soil and area of gravel). The proper value of the storage depth S0 to be included in the LID module can be calculated by using geometric properties of the surface volume. Let Ao be the surface area at the bottom of the surface pond, and let Ai be the surface area at the elevation of the invert of the first row of orifices (or at the invert of the riser if not surface orifices are included). Finally, let hi be the difference in elevation between Ao and Ai. By volumetric definition: A S -(Ao+Ai) h BMP' D -2 i (1) Equation (1) allows the determination of S0 to be included as Storage Depth in the LID module. Porosity: A porosity value of 0.4 has been selected for the model. The amended soil is to be highly sandy in content in order to have a saturated hydraulic conductivity of approximately 5 in/hr. REC considers such a value to be slightly high; however, in order to comply with the HMP Permit, the value recommended by the Copermittees for the porosity of amended soil is 0.4, per Appendix A of the Final Hydromodification Management Plan by Brown & Caldwell, dated March 2011. Such porosity is equal to the porosity of the gravel per the same document. Void Ratio: The ratio of the void volume divided by the soil volume is directly related to porosity as n/(1-n). As the underdrain layer is composed of gravel, a porosity value of 0.4 has been selected (also per Appendix A of the Final HMP document), which results in a void ratio of 0.4/(1-0.4) = 0.67 for the gravel detention layer. It should be noted that if the gravel does not occupy the entire area, then the void ratio must be reduced proportionally to the area occupied by the gravel. For example, if the gravel layer only accounts for 16.7% of the total BMP area, then the void ratio should be 0.167·0.667 = 0.111, as in the case of the 2 BMPs designed in this report. Conductivity: BMP 1 will have a conductivity of 0.00 in/hr as it will be lined to prevent any infiltration. I I I I I I I I I I I ii I I I I I -, I I I I I I I I 1- 1 I. I I I ,, I I. I I I Clogging factor: A clogging factor was not used (0 indicates that there is no clogging assumed within the model). The reason for this is related to the fairness of a comparison with the SDHM model and the HMP sizing tables: a clogging factor was not considered, and instead, a conservative value of infiltration was recommended. Drain (Flow) coefficient: The flow coefficient C in the SWMM Model is the coefficient needed to transform the orifice equation into a general power law equation of the form: (2) where q is the peak flow in in/hr, n is the exponent (typically 0.5 for orifice equation), Ho is the elevation of the centroid of the orifice in inches (assumed equal to the invert of the orifice for small orifices and in our design equal to 0) and H is the depth of the water in inches. The general orifice equation can be expressed as: Q _ ~ C E:_ z (H-HD) -4 g 144 g 12 (3) where. Q is the peak flow in cfs, D is the diameter in inches, Cg is the typical discharge coefficient for orifices (0.61-0.63 for thin walls and around 0.75-0.8 for thick walls), g is the acceleration of gravity in ft/s2, and H and Ho are defined above and are also used in inches in Equation (3). It is clear that: (in)x ABMP q hr 12 x 3600 = Q (cf s) (4) Surface Storage and Rating curves 1:· -. -~·-· ~ -~'" -·---___ ,,, • Storage UnitBASIN-! :11 11 Property Value Name BASIN-1 ! 111111----------;L .................................................... 1 X-Coordinate -4000.000 Y-Coordinate 7000.000 Description Tag Inflows NO Treatment NO Invert El. 0 MaK Depth 4.0 Initial Depth 0 Ponded Area 77700 Evap. Factor Infiltration NO Storage Curve TABULAR Functional Curve Coefficient 1000 Exponent 0 Constant 0 User-assigned name of storage unit Curve Name ···~,~---·:1 I...-~--... ,rn ... ': ' ' ' j1Ullli • Description Depth Area ... (ft) (ft2) ITl 0.00 48118 2 0.25 49916 3 0.50 51780 4 0.75 53642 5 0.83 54237 6 1.00 55502 7 1.25 57361 8 1.50 59210· 9 1.75 61074 '"' ;O~tl~t-OUTLET-1 iiJ ---------------I Property Value I llli'll ----------!,, ........ _........,........,........,,.;!11 I Name !OUTLET-1 ii II1'!'I1-ln-le~t-N-o-de _____ __,.BASIN-1 • • • ,,I1-----------~-----Outlet Node POC-1 Description Tag Inlet Off set 0 Flap Gate NO Rating Curve TABULAR/HEAD Coefficient 10.0 Exponent 0.5 Rating Curve Editor Curve Name r[DU1■111 Description Head Outflow 1"" (ft) (CFS) Cj 1 0.000 0.000 I 2 0.083 0.615 3 0.167 1.740 4 0.250 3.197 ! ! 5 0.333 4.922 I 6 0.417 6.730 ! I 7 0.500 7.772 ' ' I 8 0.583' 8.689 I I ; 9 0.667 9.518 ... I I I I I I I I I I I I :I I I I ,. I I I I I 1. I I. I I I I I I I I I I 1· I 1 Property Value Name BASIN-2 X-Cocirdinate -1000.000 Y-Coordinate 7000.000 ,I Description • Tag Inflows NO Treatment NO lnvertH 0 Max. Depth 3.5 Initial Depth . 0 Ponded Area 10793 Evap. Factor Infiltration Click to specify infiltration through the bottom of the storage unit ' r -~--------- : :~/: tJ)J:/i-~Y. • Storage Curve Editor i, ,•_ -------·- ' Curve Name [11111111 I Description i <. -· '• Depth Area IA ' [ft) (ft2) Cl 0.00 5655 2 0.25 5951 3 0.50 6255 -' 4 0.75 6576 5 1.00 6905 6 1.25 7245 7 1.50 7596 8 1.75 7957 9 2.00 8329 ,.. ,. --11· _., __ "'--·-~- !l ,.1 .J~ utlet OUTlfT-2 Property _Value Name !OUTLET~ rn:11---------,:. ..... ,_._ ... _, ... -.. ~, .... _._ ..... __ ... , ........ , .. _ ... : Inlet Node BASIN-2 [11----------;---------:1 • 01.1\let Node POC-1 Descriptiori Tag Inlet Offset 0 Flap Gate NO Rating Curve T ABLJLAR/HEAD. -- Functional Curve Coefficient 10.0 Exponent 0.5 User-assigned name of outlet . ~, Rating Curve Editor 11 - - - " .. -. ~.. ,· •-. !\I ~=======· -==·' =:=·-=· -:__.· -....,·:,1!1 11. C N Ii • urve ame i, [mi■■IA Description Head (ft) 1 0.000 2 0.083 3 0.167 4" 0.250 5 0.333 6 0.417 7 0.500 8 0.583 9· 0.667 Outflow [CFS) 0.000 0.149 0.422 0.775 1.193 1.632 1.884 2.107 2.308 , ... ~ I j ! I ' I l I I tT I r1 I I I Overland Flow Manning's Coefficient per TRWE (Reference [6]) I I .1 I I I I I I I I I I I I I I I I I I I I_ I I I I I I I I I_ !I I I appeal of a de facto value, we anticipate that jurisdictions will not be inclined to approve land surfaces other than short prairie grass. Therefore, in order to provide SWMM users with a wider range of land surfaces suitable for local application and to provide Copermittees with confidence in the design parameters, we recommend using the values published by Yen and Chow in Table 3-5 of the EPA SWMM Reference Manual Volume I -Hydrology. SWMM-Endorsed Values Will Improve Model Quality In January 2016, the EPA released the SWMM Reference Manual Volume I -Hydrology (SWMM Hydrology Reference Manual). The SWMM Hydrology Reference Manual complements the SWMM 5 User's Manual and SWMM 5 Applications Manual by providing an in-depth description of the program's hydrologic components (EPA 2016). Table 3-5 of the SWMM Hydrology Reference Manual expounds upon SWMM 5 User's Manual Table A.6 by providing Manning's n values for additional overland flow surfaces3. The values are provided in Table 1: Table 1: Manning's n Values for Overland Flow (EPA, 2016; Yen 2001; Yen and Chow, 1983). Overland Surface Light Rain Moderate Rain Heavy Rain (< 0.8 in/hr) (0.8-1.2 in/hr) (> 1.2 in/hr) Smooth asphalt pavement 0.010 0.012 0.015 Smooth impervious surface 0.011 0.013 0.015 Tar and sand pavement 0.012 0.014 0.016 Concrete pavement 0.014 0.017 0.020 Rough impervious surface 0.015 0.019 0.023 Smooth bare packed soil 0.017 0.021 0.025 Moderate bare packed soil 0.025 0.030 0.035 Rough bare packed soil 0.032 0.038 0.045 Gravel soil 0.025 0.032 0.045 Mowed poor grass 0.030 0.038 0.045 Average grass, closely clipped sod 0.040 0.050 0.060 Pasture 0.040 0.055 0.070 Timberland 0.060 0.090 0.120 Dense grass 0.060 0.090 0.120 Shrubs and bushes 0.080 0.120 0.180 Land Use Business 0.014 0.022 0.035 Semi business 0.022 0.035 0.050 Industrial 0.020 0.035 0.050 Dense residential 0.025 0.040 0.060 Suburban residential 0.030 0.055 0.080 Parks and lawns 0.040 0.075 0.120 For purposes of local hydromodification management BMP design, these Manning's n values are an improvement upon the values presented by Engman (1986) in SWMM 5 User's Manual Table A.6. Values from SWMM 5 User's Manual Table A.6, while completely suitable for the intended application to certain agricultural land covers, comes with the disclaimer that the provided Manning's n values are valid for shallow-depth overland flow that match the conditions in the experimental plots (Engman, 3 Further discussion is provided on page 6 under "Discussion of Differences Between Manning's n Values" 3 I ,, I I I I I, I I I I I I I I I I I I ATTACHMENT 8 Soils Maps & Geotechnical Report 33"757'N 33" 7 13"N N A Hydrologic Soil Group-San Diego County Area , California (Legoland) 47(fil) 470700 47(fil) 4700Xl 471CXXJ 471100 471;ID 47(fil) 470700 47CIDJ 4700Xl 4710C0 471100 471;ID Map Scale: 1 :6,720 if printed on A portrait (8.5" X 11") sheet ---====-----=====MetE!s 0 50 100 200 300 ----=====--------========>feet 0 300 roJ 1200 113'.Xl Map projection: Web Mercator Comer coordinates: WGS84 Edge tics: UTM Zone llN WGS84 USDA Natural Resources Web Soil Survey ~-Conservation Service National Cooperative Soil Survey 4713Xl 471400 4713Xl 471400 471500 471500 1/31/2017 Page 1 of 4 33" 757'N 33" 713"N Hydrologic Soil Group-San Diego County Area, California (Legoland) MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Rating Polygons D A 0 ND B BID D C D CID D D D Not rated or not available Soil Rating Lines -A ND -B -BID C CID D -,, Not rated or not available Soil Rating Points ■ A ND ■ B ■ BID USDA Natural Resources 7rm Conservation Service □ C CID ■ D □ Not rated or not available Water Features Streams and Canals Transportation +++ Rails Interstate Highways US Routes Major Roads Local Roads Background • Aerial Photography Web Soil Survey National Cooperative Soil Survey The soil surveys that comprise your AOI were mapped at 1:24,000. Warning : Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: San Diego County Area, California Survey Area Data: Version 10, Sep 12, 2016 Soil map units are labeled (as space allows) for map scales 1 :50,000 or larger. Date(s) aerial images were photographed: Nov 3, 2014-Nov 22,2014 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. 1/31/2017 Page 2 of 4 Hydrologic Soil Group-San Diego County Area, California Hydrologic Soil Group Hydrologic Soil Group-Summary by Map Unit -San Diego County Area, California (CA638) Map unit symbol Map unit name Rating CbB Carlsbad gravelly loamy B sand, 2 to 5 percent slopes LeE2 Las Flores loamy fine D sand, 15 to 30 percent slopes, er oded MIC Marina loamy coarse B sand, 2 to 9 percent slopes ScA Salinas clay, 0 to 2 C percent slopes TuB Tujunga sand, 0 to 5 A percent slopes Totals for Area of Interest Web Soil Survey Natural Resources Conservation Service National Cooperative Soil Survey Acres in AOI Percent ofAOI 21.6 15.9% 56.7 41.8% 54.8 40.4% 0.4 0.3% 2.2 1.6% 135.8 100.0% I Legoland I I I I I _I I I I I I I I I I I 1/31/2017 I Page 3 of 4 I I I I I I I I I I ,, I I I I I I Hydrologic Soil Group-San Diego County Area, California Description Hydrologic soil groups are based on estimates of runoff potential. Soils are assigned to one of four groups according to the rate of water infiltration when the soils are not protected by vegetation, are thoroughly wet, and receive precipitation from long-duration storms. The soils in the United States are assigned to four groups (A, B, C, and D) and three dual classes (AID, B/D, and CID). The groups are defined as follows: Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly wet. These consist mainly of deep, well drained to excessively drained sands or gravelly sands. These soils have a high rate of water transmission. Group B. Soils having a moderate infiltration rate when thoroughly wet. These consist chiefly of moderately deep or deep, moderately well drained or well drained soils that have moderately fine texture to moderately coarse texture .. These soils have a moderate rate of water transmission. Group C. Soils having a slow infiltration rate when thoroughly wet. These consist chiefly of soils having a layer that impedes the downward movement of water or soils of moderately fine texture or fine texture. These soils have a slow rate of water transmission. Group D. Soils having a very slow infiltration rate (high runoff potential) when thoroughly wet. These consist chiefly of clays that have a high shrink-swell potential, soils that have a high water table, soils that have a claypan or clay layer at or near the surface, and soils that are shallow over nearly impervious material. These soils have a very slow rate of water transmission. If a soil is assigned to a dual hydrologic group (AID, BID, or C/D), the first letter is for drained areas and the second is for undrained areas. Only the soils that in their natural condition are in group D are assigned to dual classes. Rating Options Aggregation Method: Dominant Condition Component Percent Cutoff: None Specified Tie-break Rule: Higher Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey Legoland 1/31/2017 Page 4 of 4 I I I I I I I I I I I I I I I I I I I ATTACHMENT 9 Summary Files from the SWMM Model PRE_DEV EPA STORM WATER MANAGEMENT MODEL -VERSION 5.0 (Build 5.0.022) ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units ............... CFS Process Models: Rainfall/Runoff ........ YES Snowmelt ............... NO Groundwater ............ NO Flow Routing ........... NO Water Quality .......... NO Infiltration Method ...... GREEN AMPT Starting Date ............ OCT-01-1951 00:00:00 Ending Date .............. SEP-30-2008 23:00:00 Antecedent Dry Days ...... 0.0 Report Time Step ......... 01:00:00 Wet Time Step ............ 00:15:00 Dry Time Step ............ 04:00:00 ************************** Volume Depth Runoff Quantity Continuity acre-feet ************************** Total Precipitation ..... . Evaporation Loss ........ . Infiltration Loss ....... . Surface Runoff .......... . Final Surface Storage ... . Continuity Error (%) ************************** Flow Routing Continuity ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDII Inflow ............. . External Inflow ......... . External Outflow Internal Outflow ........ . Storage Losses .......... . Initial Stored Volume ... . Final Stored Volume ..... . Continuity Error (%) *************************** Subcatchment Runoff Summary *************************** Subcatchment DMA-Al DMA-B1 DMA-Dl DMA-B2 DMA-D2 Analysis begun on: Analysis ended on: Total elapsed time: Sat Sat Total Precip in 674.36 674.36 674.36 674.36 674.36 Sep 30 Sep 30 00:00:15 6900.052 149.685 5902.255 924.883 0.000 -1.113 Volume acre-feet 0.000 924.883 0.000 0.000 0.000 924.883 0.000 0.000 0.000 0.000 0.000 Total Runon in 0.00 0.00 0.00 0.00 0.00 09:30:29 2017 09:30:44 2017 inches 674.360 14.629 576.843 90.391 0.000 Volume 10A6 gal 0.000 301.387 0.000 0.000 0.000 301.387 0.000 0.000 0.000 0.000 Total Evap in 1.39 3.17 29.39 3.08 29.32 Total Infil in 654.71 643.47 491.35 641.79 490.19 Total Runoff in 19.81 28.93 169 .11 30.87 170.66 Total Runoff 10A6 gal 0.88 52.25 197. 77 0.70 49.76 Peak Runoff Runoff Coe ff CFS 1.60 0.029 68.65 0.043 48. 96 0.251 0.87 0.046 12.21 0.253 I I I I I I I I I I I I I I I I I I I I I I I I I I I POST_DEV EPA STORM WATER MANAGEMENT .MODEL -VERSION 5. 0 (Build 5. 0. 022) ********************************************************* NOTE: The summary statistics displayed in this report are based on results found at every computational time step, not just on results from each reporting time step. ********************************************************* **************** Analysis Options **************** Flow Units ............... CFS Process Models: Rainfall/Runoff ........ YES Snowmelt ............... NO Groundwater ........... . Flow Routing .......... . Ponding Allowed ....... . Water Quality ......... . Infiltration Method Flow Routing Method ..... . Starting Date ........... . Ending Date ............. . Antecedent Dry Days ..... . Report Time Step ........ . Wet Time Step ........... . Dry Time Step ........... . Routing Time Step ....... . NO YES NO NO GREEN AMPT KINWAVE OCT-01-1951 00:00:00 SEP-30-2008 23:00:00 0.0 01:00:00 00:15:00 04:00:00 60.00 sec I WARNING 04: minimum elevation drop used for Conduit BYPASS-1 WARNING 04: minimum elevation drop used for Conduit UDRAIN-1 I I I I I I I I I I WARNING 04: minimum elevation drop used for Conduit BYPASS-2 WARNING 04: minimum elevation drop used for Conduit UDRAIN-2 ************************** Runoff Quantity Continuity ************************** Total Precipitation ..... . Evaporation Loss ........ . Infiltration Loss ....... . Surface Runoff .......... . Final Surface Storage ... . Continuity Error (%) ************************** Flow Routing Continuity ************************** Dry Weather Inflow Wet Weather Inflow Groundwater Inflow RDII Inflow ............. . External Inflow ......... . External Outflow Internal Outflow ........ . Storage Losses .......... . Initial Stored Volume ... . Final Stored Volume ..... . Continuity Error (%) Volume acre-feet 6604.425 837.617 1624.963 4227.783 0.000 -1.301 Volume acre-feet 0.000 4227.742 0.000 0.000 0.000 4223.271 0.000 2.957 0.000 0.000 0.036 ******************************** Highest Flow Instability Indexes ******************************** All links are stable. ************************* Routing Time Step Summary ************************* Depth inches 674.360 85.527 165.921 431.687 0.000 Volume 10A6 gal 0.000 1377.673 0.000 0.000 0.000 1376.216 0.000 0. 963 0.000 0.000 Minimum Time Step Average Time Step Maximum Time Step Percent in Steady State Average Iterations per Step *************************** Subcatchment Runoff Summary *************************** Subcatchment DMA-Al DMA-Bl DMA-Dl DMA-B2 DMA-D2 LID-1 LID-2 Total Precip in 674.36 674.36 674.36 674.36 674.36 674.36 674.36 *********************** LID Performance Summary *********************** Pent. Error Subcatchment LID Control LID-1 0.48 LID-2 0.49 LID-1 LID-2 ****************** Node Depth Summary ****************** Node POC-1 DIV-1 DIV-2 BASIN-1 BASIN-2 ******************* Node Inflow Summary ******************* Node POC-1 DIV-1 DIV-2 BASIN-1 BASIN-2 Type OUTFALL DIVIDER DIVIDER STORAGE STORAGE Type OUTFALL DIVIDER DIVIDER STORAGE STORAGE ********************** 60.00 sec 60.00 sec 60.00 sec 0.00 1.00 Total Runon in 0.00 0.00 0.00 0.00 0.00 66880.98 68005.03 Total Inflow in POST_DEV Total Evap in 52.02 76.43 84.49 84.23 82.34 1019.85 1018.35 Evap Loss in Total Infil in 322.83 190.34 122.31 120.20 134. 97 521.43 486.57 Infil Loss in Total Runoff in 306.55 413.33 475.56 479.14 464.88 66333.42 67508.09 Surface Outflow in Total Runoff 10A6 gal 12.82 722.78 507.87 10.80 134. 56 1233.28 144.30 Drain Outflow in 67555.34 68679.39 1019.89 1018.40 521.44 29183.74 37152.04 486.60 33773.53 33737.89 Average Depth Feet 0.00 0.00 0.00 0.00 0.00 Maximum Lateral Inflow CFS 0.00 123.60 13 .69 0.00 0.00 Maximum Depth Feet 0.00 0.00 0.00 2.61 2.08 Maximum Total Inflow CFS 136. 94 123.60 13.69 122.22 13.53 Maximum HGL Feet Time of Max Occurrence days hr:min 0.00 0 0.00 0 0.00 0 2.61 18823 2.08 18823 Time of Max Occurrence days hr:min 18823 17:15 18823 17:00 18823 17:00 18823 17:00 18823 .17: 00 00:00 00:00 00:00 17:15 17:05 Lateral Inflow Volume 10A6 gal 0.000 1233.271 144.299 0.000 0.000 Total Inflow Volume 10A6 gal 1376.114 1233.271 144.299 530.301 70.577 Peak Runoff CFS 1. 68 74.59 46.67 0.98 12.63 123.60 13. 69 Init. Storage in 0.00 0.00 Runoff Coeff 0.455 0.613 0.705 0. 711 0.689 0.982 0.983 Final Storage in 0.00 0.00 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Node Surcharge Summary ********************** POST_DEV Surcharging occurs when water rises above the top of the highest conduit. Node DIV-1 DIV-2 BASIN-1 BASIN-2 ********************* Node Flooding Summary ********************* Type DIVIDER DIVIDER STORAGE STORAGE No nodes were flooded. ********************** Storage Volume Summary ********************** Storage Unit BASIN-1 BASIN-2 Average Volume 1000 ft3 0.158 0.011 *********************** Outfall Loading Summary *********************** Outfall Node POC-1 System ****************'**** Link Flow Summary ******************** Link BYPASS-1 UDRAIN-1 BYPASS-2 UDRAIN-2 OUTLET-1 OUTLET-2 Flow Freq. Pent. 5.32 5.32 Type DUMMY DUMMY DUMMY DUMMY DUMMY DUMMY ************************* Conduit Surcharge Summary ************************* Hours Surcharged Max. Height Above Crown Feet Min. Depth Below Rim Feet 499679. 02 499679. 02 499679. 02 499679. 02 Avg E&I Pent Pent Full Loss Avg. Flow CFS 1. 92 1. 92 0 0 0 0 Max. Flow CFS 136.94 136. 94 0.000 0.000 2.606 2.076 Maximum Volume 1000 ft3 150.475 14.509 Total Volume 10A6 gal 1376.114 1376 .114 Maximum IFlowl CFS Time of Max Occurrence days hr:min Maximum IVelocl ft/sec 122.22 18823 17:00 1. 38 53 05:27 13.53 18823 17:00 0.16 107 11:28 121.90 18823 17:15 13. 53 18823 17:05 0.000 0.000 1.394 1.424 Max Pent Full 60 52 Max/ Full Flow Time of Max Occurrence days hr:min 18823 17:15 18823 17:04 Max/ Full Depth Conduit ---------Hours Full-------- Both Ends Upstream Dnstream Hours Above Full Normal Flow Hours Capacity Limited ----------------------------·----------------------------------------------- BYPASS-1 UDRAIN-1 0.01 0.01 0.01 0.01 0. 01 499679. 02 0. 01 499679. 02 0.01 0.01 Maximum Outflow CFS 121.90 13. 53 BYPASS-2 UDRAIN-2 0.01 0.01 0.01 0.01 Analysis begun on: Sat Sep 30 09:42:36 2017 Analysis ended on: Sat Sep 30 09:43:15 2017 Total elapsed time: 00:00:39 POST_DEV 0.01 499679.02 0.01 499679.02 0.01 0.01 I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I Attachment 2d BMP Drawdown Calculations (Note: Flow Control Facility Design Included w'ithin HMP Report) Attachment 2d: DRAWDOWN CALCULATIONS BMP-1 QLID: 1.367 cfs h (ft) Vol (ft3) Clsurf (cfs) JU (hr) 0.00 0 0.00 0.25 3403 0.00 0.692 0.50 12375 0.00 1.823 0.75 21815 0.00 1.918 1.00 31711 0.00 2.011 1.25 42074 0.00 2.106 1.50 52919 0.00 2.204 1.75 64231 0.00 2.299 2.00 76018 0.00 2.395 2.25 88271 3.20 1.148 2.50 100983 7.77 0.515 2.75 114160 10.28 0.352 2.83 118475 10.99 0.100 3.00 127802 12.29 0.199 3.25 141910 14.01 0.270 3.50 156481 15.54 0.251 3.75 171517 21.75 0.209 4.00 187017 39.17 0.135 4.25 202980 68.33 0.080 4.50 219406 104.51 0.052 4.75 236294 147.20 0.037 5.00 253645 195.42 0.028 5.25 271457 248.56 0.022 5.50 289731 306.16 0.018 5.75 308466 345.30 0.016 6.00 327661 385.84 0.015 Drying Time, T: 18.89 hr BMP-2 QLID: h (ft) 0.00 0.25 0.50 0.75 1.00 1.25 1.50 1.75 2.00 2.25 2.50 2.75 3.00 3.25 3.50 3.75 4.00 4.25 4.50 4.75 5.00 0.157 cfs Vol (ft3) Clsurf (cfs) JU (hr) 0 0.00 422 0.00 0.747 1536 0.00 1.972 2712 0.00 2.081 3954 0.00 2.196 5262 0.00 2.315 6640 0.00 2.438 8091 0.77 0.740 9617 1.88 0.285 11220 2.49 0.190 12905 2.98 0.162 14674 3.40 0.147 16529 3.77 0.138 18473 4.54 0.125 20508 10.82 0.072 22638 20.60 0.037 24866 37.51 0.021 27193 60.31 0.013 29623 77.75 0.010 32158 95.65 0.008 34801 115.00 0.007 Drying Time, T: 13.70 hr 2 • (Vol· 1 -Vol·) /J.t = l+ l 3600 • ( Qsurf;+1 + Qsurf; + 2 • QuD) I I I I I I I I I I I I I I I I • I I I I I I I I I I I I I I I I I I I I I ATTACHMENT 3 Structural BMP Maintenance Information Use this checklist to ensure the required information has been included in the Structural BMP Maintenance Information Attachment: Preliminary Design/Planning/CEQA level submittal: Attachment 3 must identify: 18] Typical maintenance indicators and actions for proposed structural BMP(s) based on Section 7. 7 of the BMP Design Manual Final Design level submittal: Attachment 3 must identify: □ Specific maintenance indicators and actions for proposed structural BMP(s). This shall be based on Section 7. 7 of the BMP Design Manual and enhanced to reflect actual proposed components of the structural BMP(s) □ How to access the structural BMP(s) to inspect and perform maintenance □ Features that are provided to facilitate inspection (e.g., observation ports, cleanouts, silt posts, or other features that allow the inspector to view necessary components of the structural BMP and compare to maintenance thresholds) □ Manufacturer and part number for proprietary parts of structural BMP(s) when applicable □ Maintenance thresholds for BMPs subject to siltation or heavy trash(e.g., silt level posts or other markings shall be included in all BMP components that will trap and store sediment, trash, and/or debris, so that the inspector may determine how full the BMP is, and the maintenance personnel may determine where the bottom of the BMP is . If required, posts or other markings shall be indicated and described on structural BMP plans.) □ Recommended equipment to perform maintenance □ When applicable, necessary special training or certification requirements for inspection and maintenance personnel such as confined space entry or hazardous waste management - --- --- -- ------ -- Structural BMP Maintenance Information The table below identifies the specific maintenance indicators and actions for the proposed structural BMPs. The two (2) BMPs for this project are both Biofiltration Basins. All proposed BMPs shall be access via proposed access road. No features proposed to facilitate inspections as all inspections/measurements are based on visual observation. For most maintenance actions, truck is sufficient. A 10-lSyd truck or backhoe may be necessary when removing sediment from BMP. No proprietary parts or training necessary to perform activities for proposed BMPs. BMP: Biofiltration Basins MAINTENANCE ACTIVITIES - MEASUREMENT ROUTINE ACTION MAINTENANCE INDICATOR FIELD MEASUREMENT FREQUENCY MAINTENANCE ACTIVITY Vegetation Average vegetation height -Visual observation and Cut vegetation to an average height of 6-Management for greater than 12-inches, random measurements Annually, prior to start of wet inches and remove trimmings. Remove -Aesthetics emergence of trees or woody throughout the side slope season any trees, or woody vegetation. (optional) vegetation, area Soil Repair Evidence of erosion Visual observation Annually, prior to start of Reseed/revegetate barren spots prior to wet season wet season. Standing water for more than Annually, 96 hours after a Drain facility. Corrective action prior to Standing Water Visual observation wet season. Consult engineers if 96 hrs target storm (0.60 in) event immediate solution is not evident. Trash and Debris Trash and Debris present Visual observation Annually, prior to start of Remove and dispose of trash and debris wet season Measure depth at apparent Remove and properly dispose of Sediment Sediment depth exceeds 10% maximum and minimum Annually, prior to start of sediment. Regrade if necessary. Management of the facility design accumulation of sediment. wet season (expected every 2 years) Calculate average depth Annually, prior to start of Corrective action prior to wet season. Underdrains Evidence of Clogging Visual Observation Consult engineers if immediate solution wet season is not evident. Inlet structures, outlet structures, side slopes or other General features damaged, significant Annually, prior to start of Corrective action prior to wet season. Maintenance erosion, burrows, emergence of Visual observation Consult engineers if immediate solution Inspection trees or woody vegetation, wet season is not evident. graffiti or vandalism, fence damage, etc. Reporting - Frequency (# of times oer year) 1.0 -~--------~- 1.0 -- 1.0 -- 1.0 --- 0.5 1.0 1.0 1.0 ATTACHMENT 4 City standard Single Sheet BMP {SSBMP) Exhibit [Use the City's standard Single Sheet BMP Plan.] NOTE: The City of Carlsbad Standard Single Sheet BMP Exhibit will not be different than the exhibit provided in Attachment 1 a because: (a) the current grading information of LEGOLAND is not available in a single file; and (b) the project consists of 2 Regional (LEGOLAND level) BMPs which will treat an unknown area in the future (future re-development) up to the values calculated here. Please refer to the SSBMP exhibit provided in this section. I I I I I I I I I I I I I I I I I I I r '-..,J :::::---:::: I ( I ff l~f ~\ 1 ~1 ~ LEGEND OMA BOUND ARY SOIL TYPE BOUNDARY WATER SLIDE WP-17 PARKING MOD IFICATION LLCH20 HOTEL ==------------ __...-+BMP-1 (SEE DETAIL) I I \ I I BMP-1 (SEE DETAIL) --" ,.-----,-BMP-2 (SEE DETAIL) --- -- J THE CRG~ING DR ----DARK RIDE JD-18 --II REGIONAL BMP BASIN i u SAVE QATE: 3/5/20,g ~ ~T DATE. 3/12/2c·a ~ ~ .,.,E NAME: o: \Ac::::d\'243 Legolof'c\Civ: \Exh·~rts\i1yd~:i.oc;y Exhroi,.cwg [ ~ _,..,-~......._____ BMP DETAIL ,.,~ ~ / ._J ' _,_/ ~ , .__,_/ '- I f ~ I 200 100 0 200 400 -.: CURRENT PROJECTS TREATED BY REGIONAL BMPs WATER SLIDE WP -17 Ao,sTURBED = 0.56 AC PARKING MODIFICATION Ao,sTURBED = 0.14 AC LLCH20 HOTEL Ao,sTURBED = 6.962 AC DARK RIDE JD-18 Ao,sTURBED = 0.900 AC { ONLY 0.14 ACRES DISTURBED OVER THE LARGER PROJECT BOUNDARY SHOWN SCALE: 1" = 200' DRAINAGE BAS IN A1 B1 01 X1 -NOR TH AREA 1 B2 D2 X2 -NORTH AREA 2 \ \ I .. ---- 600 1.644 AC 64.403 AC 39.884 AC 53. 790 AC 0.827 AC 10.733 AC 12. 710 AC a~DAY STUDY 46.850 AC ----------" ' I I I I I I I ~ PARTY RESPONSIBLE FOR MAINTENANCE: NAM E: =LE=G~O=L~A~N~D ____ _ ADDRESS: 1 LEGOLAND DRIVE CON TAC T: ERIK FLORES CARLSBAD, CA 92008 EMA IL: ERIKF@PMAINC.COM PHONE NO: (877) 396-5346 PLANS PREPARED BY: NAME: LUIS PARRA SIGNATURE: ----+(~_-'-" ___ w_k __ I COMPANY: REC CONSULTANTS ADDRESS: 27349 JEFFERSON AVE, SUITE 112 TEMECULA, CA 92590 PH ON E NO: (951) 693-2400 BMP NOTES 60 30 0 , ... _ ;. ... ..: ·~·. .;-•; "-:>..·~-~ !< tC[ • .,c.•·· -~-f * ( ,,, ., * 60 SCALE: 1" = 60' 1. THESE BMPS ARE MANDATORY TO BE IN STALLED PER MANUFACTURER 'S RECOMMENDATION OR THES E PLANS. 2. NO CHANGES TO THE PROPOSED BMPS ON THIS SHEET WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. _J 120 3. NO SUBSTITUTIONS TO THE MATERIAL OR TYPE OR PLANTING TYPES WITHOUT PRIOR APPROVAL FROM THE CITY ENGINEER. 4. NO OCCUPANCY WILL BE GRANTED UNTIL THE CITY IN SPECTION STAFF HAS INSPECTED THIS PROJECT FOR A APPROPRIATE BMP CONSTRUCTION AND INSTALLATION. 5. REFER TO MAIN TENANCE AGREEMENT DOCUMENT. 6. SEE PROJECT SWIMP FOR ADDI TIONAL INFORMATION. BMPTABLE BMP ID# BMP TYP E SYMBOL CASQA NO. QUANTITY DRAWING NO SHEET NO(S) INSPECTION MAIN TENANCE FREQU ENCY FREQUENCY TREATMENT CONTROL N/A -------- HYDROMODIFICATION & TREATM ENT CONTROL 180 ® BIOFI L TRA TION I I TC-32 29,826 SOFT 498-2C 3, 4, 5 & 6 QUARTERLY SEM I-ANNUALLY AREA © BIOFIL TRA TION I I TC-32 3,429 SOFT AREA HYDROMODIFICATION N/A ---- LOW IMPACT DESIGN (LID) CD-© FOREBAY I I INCLUDED IN 4 EA TC 20.21 22 SOURCE CONTROL N/A ---- • CHOOSE FROM THE LIST BELOW FOR COMPLETING THE FIELDS IN THE INSPECTIONS & MAINTENANCE FREQUENCY COLUMNS: -ANNUAL -NONE -SEMI-ANUALL Y -WEEKLY OU ARTERL Y 1 TIME PER YEAR -BIMONTHLY -2 TIMES PER YEAR -MONTHLY -3 TIMES PER YEAR -AS NEEDED -4 TIMES PER YEAR Civil Engineering • Environmental Land Su rveying 2442 Second Avenue San Diego, CA 92101 498-2C 6 QUARTERLY SEMI-ANNUALLY ---- 498-2C 3, 5 & 6 QUARTERLY QUARTERLY ---- Consultants, Inc. (619)232-9200 (619)232-9210 Fax I SHfET I CITY OF CARLSBAD I SHElETS I ENGINEERING DEPARTMENT SINGLE SHEET BMP SITE PLAN FOR LEGOLAND REGIONAL BIOFILTRATIO N & HYDROMODIFICATION FACILITY GR NO 2017-0025 I RECORD COPY PROJECT NO. SDP15-26 la/ !J/1 !'J/l'l DRAWING NO. DATE INITIAL DATE INITIAL DATE INITIAL ENGINEER OF WORK REVISION DESCRIPTION INITIAL DATE 498-2C OTHER APPROVAL CITY APPROVAL NE Job # 121-149.1 ADDENDUM NO. 3 LEGOLAND PARKING STRUCTURE #2 SDP 2021-0028 / GR 2022-0007 / DWG 537-1A / GR 2023-0025 Date 1/9/2024 LEGOLAND Regional Water Quality Basin ADDENDUM Project Name Date Project ID DWG No. Notes 1 LEGOLAND Project 2020 11/6/18 SDP 18-17 515-2A Revised Water Quality & Hydromod Calcs 2 LEGOLAND Fun Town Stage 11/8/23 SDP2023-0003 DWG-333-2Y – Delta 4 DWG-333-2H – Delta B Revised Water Quality & Hydromod equivalent area calcs, addition of attachment 1f: Trash Capture BMP Requirements. 3 LEGOLAND Parking Structure #2 1/9/2024 SDP 2021-0028 537-1A Revised Water Quality, Hydromod Calcs, and Trash Capture for east portion of Parking Garage #2. 4 Garden Restroom 11/8/23 SDP2023-0011 DWG-333-2Y – Delta 4 DWG-333-2H – Delta B Revised Water Quality & Hydromod equivalent area calcs. Covered by trash capture addendum 2. 5 Project 2025 11/8/23 SDP2023-0003 DWG-333-2Y – Delta 4 DWG-333-2H – Delta B Revised Water Quality & Hydromod equivalent area calcs. Covered by trash capture addendum 2. ~ Nasland NE Job # 121-149.1 ADDENDUM #3 AMENDMENT TO LEGOLAND REGIONAL BIOFILTRATION BASIN SWQMP (SDP15-26) EQUIVALENT AREA CALCULATION FOR WATER QUALITY AND HYDROMODIFICATION PURPOSES FOR LEGOLAND PARKING STRUCTURE #2 SDP 2021-0028 / GR 2022-0007 / DWG 537-1A Date 1/9/2024 Summary The purpose of this addendum is to update the DMA map to account for the proposed improvements and incorporate trash capture measures for the tributary basin of this project. The site includes a total project limit of disturbance area of 3.012 acres. Within the site project disturbance limits there is an existing 109,827 sf impervious area and proposed 121,081 sf proposed impervious area which results in a total site increase of 10.2%. The remaining Equivalent Area has been calculated based on the increase of impervious area to be deducted from the LEGOLAND regional BMPs for Water Quality and Hydromodification Compliance. According to the LEGOLAND Regional Water Quality and Hydromodification BMP report (SDP 15-26 / CDP15-50, dated 6/30/18) the regional water quality and hydromodification facility adjacent to Palomar Airport Road has the capacity to treat 45.766 acres of additional equivalent area for water quality purposes and up to 72.771 acres of additional equivalent area for hydromodification purposes. After inclusion of Addendum 1 LEGOLAND 2020 in 2/21/19 the remaining equivalent area for water quality is 44.630 acres and the remaining equivalent area for hydromodification is 71.635 acres. The LEGOLAND Parking Structure #2 will be constructed within the DMA of the Regional Biofiltration Basin. The equivalent area of the LEGOLAND Guest Parking Structure is 0.26 acres. The remaining equivalent area for water quality will reduce to 44.630 acres and the remaining equivalent area for hydromodification is 71.635 acres. ~ Nasland NE Job # 121-149.1 City of Carlsbad BMP Design Manual Chapter 4.4 requires trash capture devices for the development of The LEGOLAND Parking Structure #2. This requirement will be met and memorialized with installing ‘FlexStorm Connector Pipe Screen (CPS)’ trash capture to the proposed A4 Cleanout downstream of DMA 2 at POC 2 per SDP 2021-0028/CDP2021-006/DWG No. 537.1A hydrology study prepared by Nasland Engineering. CPS specifications and hydraulic calculations provided in this Addendum. Please see the following attachments included in this addendum: DMA map of the LEGOLAND Parking Structure #2, Equivalent Area Calculations, and trash capture device specifications and calculations. LEGOLAND Regional Water Quality Basin ADDENDUM Project SDP No. Inclusion Date Water Quality Hydromodification Regional SWQMP SDP 15-26 06/30/2018 45.766 acres 72.771 acres 1 LEGOLAND 2020 11/06/2018 -1.136 acres -1.136 acres AVAILABLE 44.630 71.635 2 LEGOLAND Parking Structure #2 SDP 2021- 0028 05/05/2022 -0.26 acres -0.26 acres REMAINING 44.370 acres 71.375 acres ~ Nasland NE Job # 121-149.1 DECLARATION OF RESPONSIBLE CHARGE I hereby declare that I am the engineer of work for this project, that I have exercised responsible charge over the design of the Legoland Parking Structure #2 project as defined in section 6703 of the Business and Professions Code, and that the design is consistent with the current standards. I understand that the check of the project drawings and specifications by the City of Carlsbad is confined to a review only and does not relieve me, as Engineer of Work, of my responsibilities for project design. James J linn Date R.C.E. 84231 Exp. 9-30-2025 1/09/24 ~ Nasland BASIN DATA: PROPOSED CONDITIONS WATER QUALITY AND HYDROMODIFICATION EQUIVALENT AREA CALCULATION 1 Project Name:Legoland Guest Parking Structure 2 Date of Calculation: 1/24/2022 3 Total Area Impacted:3.012 AC 4 Existing Pervious Area:0.493 AC 5 Existing Impervious Area:2.519 AC 6 Existing Self-contained:0 AC 7 Proposed Pervious:0.232 AC 8 Proposed Impervious:2.780 AC 9 Proposed self-contained:0 AC 10 C coefficient (Post dev.)0.84 AC 11 Existing area = proposed area?YES 12 Equivalent Area:2.525 AC Not Including this project, this is the status of treatment for LEGOLAND: 13 Water Quality Equivalent Area:44.630 AC 14 Hydromodification Eq. Area:71.635 AC After this project, this will be the remaining treatment for LEGOLAND: 15 Water Quality Equivalent Area:42.105 AC 16 Hydromodification Eq. Area:69.110 AC I • ti EXISTING PARKING STRUCTURE ■ ■ DMA1 ARE.A= 3.012 AC C-0.84 EQUIV. AREA-2.525 AC ■ DRAINS TO EXISTING LEOOLAND REGIONAL BMP • • ~ ~ ---------t------125--------------- ~--------125-------1 I DMA f1.1 1.23 AC Q(1 'tEAR 1 HOUR) • 1.20CFS 1 YEAR-1 HOUR Storm DMA 1.1 2.1 C Value 0.90 0.90 Tc (mins) 5.00 5.00 ------------ ~ -----+-1201---- P1 = 0.412 in Intensity Area (I, in/hr) (acres) 1.09 1.23 1.09 1.22 DMA f2.1 1.22 AC Q(1 'tEAR 1 HOUR) • 1.11CFS ---i = 7.44P6T, -0,G 5 ~ / Runoff (Q, cfs) 1.20 1.19 ---- I REA 1' I I 1- 1 I I I I 0 50 LEGEND PROPOSED IMPROVEMENTS IMPERVIOUS AREA PARKING STRUCTURE DMA PERIMITER (TOTAL DISTURBED AREA) TRIBUTARY AREAS TO TRASH CAPTURE STORM DRAIN FLOW LINE SITE DATA EXHIBIT ---- ---- -SD -SD -SD - <= <= <= <= TOTAL DISTURBED AREA: 3.012 ACRES HYDROLOGIC SOIL GROUP: D DEPTH TO GROUNDWATER: GREATER THAN 20' NATURAL HYDROLOGIC FEATURES: N/ A CRITICAL COARSE SEDIMENT: N/ A PRE VS POST IMPERVIOUS AREA DMA 1: DMA #2.1 (TRIBUTARY AREA TO PER ADDENDUM 3): DMA #1.1 (TRIBUTARY AREA TO PER ADDENDUM 3): EXISTING IMPERVIOUS: EXISTING PERVIOUS: PROPOSED IMPERVIOUS: PROPOSED PERVIOUS: % IMPERVIOUS INCREASE: 3.012 ACRES CPS TRASH CAPTURE 1.220 ACRES CPS TRASH CAPTURE 1.230 ACRES 2.519 ACRES 0.493 ACRES 2.780 ACRES 0.232 ACRES 10.3% Nasland Civil Engineering Surveying T (858) 292-7770 4740 Ruffner Street San Diego, CA 92111 100 Land Planning nasland.com SDP2021-0028 / CDP2021-0066 DWG537-1A DMA + HMP EQUIVALENT AREA EXHIBIT CITY OF CARLSBAD ENGINEERING DEPARTMENT PROJECT NO. SCALE 1''=50' I 11 I 1/9/24, 10:36 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=33.1251&lon=-117.3079&data=depth&units=english&series=pds 1/4 NOAA Atlas 14, Volume 6, Version 2 Location name: Carlsbad, California, USA* Latitude: 33.1251°, Longitude: -117.3079° Elevation: 127 ft** * source: ESRI Maps** source: USGS POINT PRECIPITATION FREQUENCY ESTIMATES Sanja Perica, Sarah Dietz, Sarah Heim, Lillian Hiner, Kazungu Maitaria, Deborah Martin, Sandra Pavlovic, Ishani Roy, Carl Trypaluk, Dale Unruh, Fenglin Yan, Michael Yekta, Tan Zhao, GeoffreyBonnin, Daniel Brewer, Li-Chuan Chen, Tye Parzybok, John Yarchoan NOAA, National Weather Service, Silver Spring, Maryland PF_tabular | PF_graphical | Maps_&_aerials PF tabular PDS-based point precipitation frequency estimates with 90% confidence intervals (in inches)1 Duration Average recurrence interval (years) 1 2 5 10 25 50 100 200 500 1000 5-min 0.121 (0.102‑0.146) 0.153 (0.129‑0.184) 0.197 (0.165‑0.238) 0.235 (0.195‑0.285) 0.288 (0.231‑0.363) 0.331 (0.260‑0.427) 0.378 (0.288‑0.500) 0.427 (0.317‑0.583) 0.499 (0.354‑0.711) 0.558 (0.381‑0.826) 10-min 0.174 (0.146‑0.209) 0.220 (0.185‑0.264) 0.283 (0.237‑0.341) 0.336 (0.279‑0.409) 0.413 (0.331‑0.520) 0.475 (0.372‑0.612) 0.541 (0.413‑0.716) 0.613 (0.454‑0.835) 0.715 (0.507‑1.02) 0.800 (0.547‑1.18) 15-min 0.210 (0.177‑0.252) 0.266 (0.223‑0.319) 0.342 (0.286‑0.412) 0.407 (0.338‑0.494) 0.499 (0.400‑0.629) 0.574 (0.450‑0.741) 0.654 (0.499‑0.866) 0.741 (0.549‑1.01) 0.865 (0.613‑1.23) 0.968 (0.661‑1.43) 30-min 0.297 (0.250‑0.356) 0.375 (0.315‑0.451) 0.482 (0.404‑0.581) 0.574 (0.476‑0.698) 0.704 (0.564‑0.888) 0.810 (0.635‑1.04) 0.923 (0.705‑1.22) 1.04 (0.774‑1.42) 1.22 (0.865‑1.74) 1.36 (0.933‑2.02) 60-min 0.412 (0.346‑0.494) 0.520 (0.437‑0.625) 0.668 (0.560‑0.806) 0.795 (0.661‑0.967) 0.977 (0.783‑1.23) 1.12 (0.881‑1.45) 1.28 (0.977‑1.69) 1.45 (1.07‑1.98) 1.69 (1.20‑2.41) 1.89 (1.29‑2.80) 2-hr 0.565 (0.475‑0.678) 0.707 (0.594‑0.850) 0.901 (0.755‑1.09) 1.06 (0.885‑1.30) 1.30 (1.04‑1.64) 1.49 (1.16‑1.92) 1.69 (1.29‑2.23) 1.90 (1.41‑2.59) 2.21 (1.56‑3.15) 2.46 (1.68‑3.64) 3-hr 0.673 (0.566‑0.808) 0.841 (0.707‑1.01) 1.07 (0.896‑1.29) 1.26 (1.05‑1.54) 1.54 (1.23‑1.93) 1.75 (1.37‑2.26) 1.98 (1.51‑2.62) 2.23 (1.65‑3.04) 2.58 (1.83‑3.68) 2.87 (1.96‑4.24) 6-hr 0.892 (0.750‑1.07) 1.12 (0.939‑1.34) 1.42 (1.19‑1.71) 1.68 (1.39‑2.04) 2.03 (1.63‑2.56) 2.31 (1.81‑2.98) 2.60 (1.99‑3.45) 2.92 (2.16‑3.98) 3.35 (2.38‑4.78) 3.70 (2.53‑5.48) 12-hr 1.16 (0.975‑1.39) 1.47 (1.23‑1.76) 1.87 (1.57‑2.26) 2.21 (1.84‑2.69) 2.67 (2.14‑3.37) 3.03 (2.38‑3.91) 3.41 (2.60‑4.51) 3.79 (2.81‑5.17) 4.33 (3.07‑6.17) 4.75 (3.25‑7.03) 24-hr 1.44 (1.27‑1.66) 1.84 (1.62‑2.13) 2.37 (2.08‑2.75) 2.80 (2.44‑3.28) 3.39 (2.86‑4.09) 3.84 (3.18‑4.73) 4.31 (3.49‑5.43) 4.79 (3.78‑6.19) 5.44 (4.13‑7.32) 5.95 (4.37‑8.28) 2-day 1.76 (1.55‑2.04) 2.27 (2.00‑2.63) 2.94 (2.59‑3.42) 3.49 (3.04‑4.09) 4.24 (3.58‑5.12) 4.82 (3.99‑5.93) 5.41 (4.38‑6.81) 6.02 (4.75‑7.79) 6.85 (5.20‑9.22) 7.50 (5.51‑10.4) 3-day 1.97 (1.74‑2.28) 2.56 (2.25‑2.96) 3.32 (2.92‑3.86) 3.96 (3.45‑4.63) 4.82 (4.08‑5.82) 5.49 (4.55‑6.76) 6.18 (5.00‑7.78) 6.89 (5.43‑8.91) 7.86 (5.96‑10.6) 8.62 (6.33‑12.0) 4-day 2.15 (1.90‑2.49) 2.80 (2.46‑3.24) 3.65 (3.21‑4.24) 4.35 (3.80‑5.10) 5.32 (4.50‑6.42) 6.07 (5.03‑7.47) 6.84 (5.54‑8.61) 7.63 (6.02‑9.88) 8.73 (6.62‑11.7) 9.59 (7.04‑13.3) 7-day 2.51 (2.22‑2.90) 3.29 (2.90‑3.81) 4.33 (3.80‑5.02) 5.18 (4.52‑6.06) 6.36 (5.38‑7.68) 7.28 (6.04‑8.97) 8.24 (6.67‑10.4) 9.23 (7.28‑11.9) 10.6 (8.04‑14.3) 11.7 (8.57‑16.2) 10-day 2.78 (2.46‑3.22) 3.67 (3.24‑4.25) 4.85 (4.26‑5.64) 5.83 (5.09‑6.83) 7.19 (6.08‑8.68) 8.26 (6.84‑10.2) 9.36 (7.58‑11.8) 10.5 (8.29‑13.6) 12.1 (9.18‑16.3) 13.4 (9.82‑18.6) 20-day 3.37 (2.98‑3.90) 4.50 (3.96‑5.21) 6.01 (5.28‑6.98) 7.28 (6.35‑8.52) 9.05 (7.65‑10.9) 10.4 (8.66‑12.9) 11.9 (9.65‑15.0) 13.5 (10.6‑17.4) 15.6 (11.8‑21.0) 17.4 (12.7‑24.1) 30-day 4.02 (3.54‑4.65) 5.39 (4.75‑6.24) 7.24 (6.36‑8.41) 8.80 (7.68‑10.3) 11.0 (9.30‑13.3) 12.8 (10.6‑15.7) 14.6 (11.8‑18.4) 16.5 (13.0‑21.4) 19.3 (14.6‑26.0) 21.5 (15.8‑29.9) 45-day 4.75 (4.19‑5.49) 6.37 (5.61‑7.37) 8.58 (7.54‑9.96) 10.5 (9.12‑12.2) 13.1 (11.1‑15.8) 15.3 (12.6‑18.8) 17.5 (14.2‑22.1) 20.0 (15.7‑25.8) 23.4 (17.7‑31.5) 26.2 (19.2‑36.4) 60-day 5.50 (4.85‑6.37) 7.36 (6.48‑8.52) 9.91 (8.71‑11.5) 12.1 (10.5‑14.1) 15.2 (12.8‑18.4) 17.7 (14.7‑21.8) 20.4 (16.5‑25.7) 23.3 (18.4‑30.2) 27.5 (20.8‑37.0) 30.9 (22.7‑43.0) 1 Precipitation frequency (PF) estimates in this table are based on frequency analysis of partial duration series (PDS). Numbers in parenthesis are PF estimates at lower and upper bounds of the 90% confidence interval. The probability that precipitation frequency estimates (fora given duration and average recurrence interval) will be greater than the upper bound (or less than the lower bound) is 5%. Estimates at upper bounds are not checked against probable maximum precipitation (PMP) estimates and may be higher than currently valid PMP values. Please refer to NOAA Atlas 14 document for more information. Back to Top PF graphical ------ □: II II II II I C II II II II II I C II II II I C II II II I Ei i II II C II II II C II II II D I II II C II II II C II II II C II I II C II II C II II C II II II C II II II C II II II C II II II C II II II D I II II 1/9/24, 10:36 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=33.1251&lon=-117.3079&data=depth&units=english&series=pds 2/4 Back to Top Maps & aerials Small scale terrain 30 25 c:: ..c: 20 .j...J C. QJ -c i;: 15 0 '.i:i 19 ·a 10 e c.. 5 0 i;: C: E .E I I Ll'l 0 ,-1 30 25 c:: ..c: 20 .j...J C. Q) -c i;: 0 15 '.i:i 19 ·a ·v 10 ~ c.. 5 0 1 PDS-based depth-duration-frequency (DDF) curves Latitude: 33.1251 °, Longitude: -117 .3079° I JI ,I; I ~ ~ ,I 1 ~ ;j, ~ ~ ~ / ......-'.: v.: / ~ ~ ~ ::.--'. ~ I'" ~ ,,,,. ~ ~ :::: ~ ~ % c;::: ,,., ~~ ~ ...... -..-:::: i.--,.,_ ~ I I C: c:: c:: ... ... ... -->, >, >, >, >, >, >, >, >, .E .E .E .r;;;. .r;;;. .r;;;. .r;;;. .r;;;. re re re re re re re re re N 1'11 th I I -c -c -c "C -c -c -c -c -c N ~ I I I Duratio'ii N 1'11 .,\-' I I I I I Ll'l 0 0 r--0 0 0 Ll'l 0 ,-1 "1 +,D ,-1 N "1 s:f' l,D 2 5 10 25 50 100 200 500 1000 Average recurrence interval (years) f>lOAA Atlas 14, Volume 6, Version 2 Created (GMT}: Tue Jan 9 lB:39: 2 7 2 02 4 Average recu110nce irnteiva'I {years) 1 2 5 10 25 50 100 200 500 1000 Duration 5-min 10-mln 15-mln 30-mln 60-mln 2-hr 3-tlr ,6-t1r 12~hr 24-hr 2-ciay 3-ciay 4-day 7-ciay 10-day 20-day 30-day 45-day 60-day 1/9/24, 10:36 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=33.1251&lon=-117.3079&data=depth&units=english&series=pds 3/4 Large scale terrain Large scale map Large scale aerial + – 3km 2mi + – 100km 60mi + – 100km 60mi o,mard Cl Ensenada Cl Salton Sea 1/9/24, 10:36 AM Precipitation Frequency Data Server https://hdsc.nws.noaa.gov/pfds/pfds_printpage.html?lat=33.1251&lon=-117.3079&data=depth&units=english&series=pds 4/4 Back to Top US Department of Commerce National Oceanic and Atmospheric Administration National Weather Service National Water Center 1325 East West Highway Silver Spring, MD 20910 Questions?: HDSC.Questions@noaa.gov Disclaimer + – 100km 60mi Page | 13 APPENDIX A. Design Criteria and Sample Calculations CPS FLOW CALCULATIONS STANDARD LENGTHS. VARIABLE BYPASS HEIGHTS ADS CPS units are !itandardized with a pre-set Length of s.creen [L). The heigJlt of the bypass is the variable used to confirm th at the tota I 0.vpo,• for the CPS with lid design exceeds the Max Q,0 for a certain CB width. The sizing table below shows th e resultant Or"I?'" for the various B (bypa.ss heights). Defini:ning the Orifice bypass equation tor CPS with deflector lids °-t,ypass = CbypassAbypass ✓ 2g H ~ •• = .6 (coelificient) g= 3 2.2 ftls' ~ =L tfu:,(1EJ-.•,f>ChlbotJaahdJ.hll ~ = depth of water to centroid of bypass CPS U SIZING TABLE MINIMUM BYPASS RATINGS for lid desi ns with 6" Freeboard CPS Flow Rates by Model B(bypass height)= 4" B (bypass ll [bypass B(bypass B (bypass height)= 6" height) =8" height)= 10" height) = 12" Model Screen Screen A,.,-.,,0 et 0.,,.,0 Flow lt.,pm Q4 H., Length Height D~!'.!1 11~) Rate (ds) (ft) Q6 H, QS Hs QlO H10 Q12 3L18H-B ass-Sha e 3 18 1.80 8.72 3.00 3.93 8 5.52 7 6.81 6 7.77 5 13.19 4l18H-Bypass-Shape 4 18 2..45 11.84 Sl18H-Bypass-Shape 5 18 3.09 14.96 Determine CPS model number based on screen length and height -bypass height -and s.creen shape_ For example Model 3U8H-8-U is 3' wide x 18" tall, has 8" bypass height, an d is "U" shaped. Cu!itom lengths and heights are available for any catch basin. Example Seleotion and Calculation: 4.00 5.24 8 7.35 7 9.08 5.00 6.55 8 9.19 7 11.35 &yp.i~!. r.'tirn,;::-. in 81.-ck ;;;Je for 3.5' Vb MinimWT:'I C;tc 8.i:!:in De,p &yp.r.~!. r;;;tir;!. in Re .ire r~• Vb Minimum Catch B.tl"11 ~pths- 6 10.36 5 17.58 6 12.95 5 2.1.98 Assume we have a 7' wide catch basin with a depth Vb of 3.5' and 18" connector pipe. The Ma:x Q,is 1.2 CFS and the Ma:x Q10 is 5.3 CFS per the hydrology !itudy table to the right. Select th e appropriate s.creen to pass the 1 year flow then determine the minimum bypass height required to pass the 10 year flow. The 3L18H-6B s.creen (highlighted tn green) passes 8.52 CFS far e:xceeding the 1.2 CFS requirement. According to the sizing table that unit will bypass 5..5-2 CFS with a 6" bypass heigllt based on the OrifiGe Flow bypass equation which is greater than the required 5.3 CFS maximum lOyrflow seen by the 7' wide catch basin. The bypass is calculated as follows: Q"IP',. = ~,,.A,,~, \fiiH ~ = .6 (orifice coefficiem) g= 32.2 ft/s2 A,,.,,,.,. = L [1e"-""'°''"""'IX h •>w='-"<;ht] = (3 X 6/12) = 1.5 ft2 H = depth of water to centroid of bypass (maintaining 6" freeboard) We need to check Clearance and determine the H Clearance = Vd epth-Hscreen-Hbypass-rnrb height (mu!it always be > 4") Clearance = 42"-18"-6"-8"=10'" H = H bypass/2 + Cleara nee -6" freeboa rd (sized conservatively) H = 6/2 + 10 -6 = T' or .583 ft Finally, O.Y?"' = ~po,,A'Y?"' ,fijiii a_,= ,6 X 1.5 v'2 X 32, 2 X. 583 = 5.52.cfS f:qr,Bl.oo H,, 10 10 10 Ca·tch B,11sin R:,11tine~ far~ y!!.u ,11nd ten y9r rain ~enls 11:S determlMd by LA County h dra ~tu:dJB CII widd, M,xO,m Ma°-1,1 () (ml tct.) l-5 u 0.6 5.3 1.2 10 7-5 1.7 1• 10 2.2 21 ll.9 ].1 ZS 17.3 3.S Page | 14 Appendix B. Specification and Design Drawings ADS FLEXSTORM: CONNECTOR PIPE SCREEN (CPS) PROTECTIVE BYPASS UD CPS L 14 GA 5 MM PERFORATED STAINLESS STEEL 50% OPEN AREA SIZING TABLE CPS Flow Rates by Model M odel Screen Screen ~c:rtien {Net O screen Flow Length Height open ;,re;,) Rate (cfs) 3Ll8H-Bypass-Shape 3 18 1.80 8 .72 4Ll8H-Bypass-Shape 4 18 2.45 11.84 SL18H-Bypass-Shape 5 18 3.09 14.96 lt,ypass (ft) 3.00 4 .00 5.00 CPS U 12 GA U-CHANNEL STIFFENER (Typ.) 3/8" WEDGE ANCHOR BOLTS SLOTTED HOLES FOR SLOPED CATCH BASIN FLOORS CPS U-EXT MINIMUM BYPASS RATINGS for lid designs with 6" Freeboard B (bypass B (bypass B (bypass B (bypass B (bypass hei ht =4" hei ht = 6" hei ht = 8" hei ht = 10" hei ht = 12" Q4 H• Q6 H6 Q8 Ha QlO H10 Q12 H12 3.93 8 5.52 7 6.81 6 7 .77 5 13.19 10 5.24 8 7.35 7 9.08 6 10.36 5 17.58 10 6.55 8 9 .19 7 11.35 6 12.95 5 21.98 10 Determine CPS model number based on screen length and height -bypass height -and screen shape. For example Model 3L18H-8-U is 3' wide x 18" tall, has 8" bypass height, and is "U" shaped. Custom lengths and heights are available for an catch basin. 14GA5MM PERFORATED SCREEN50% OPEN ---------------------7 N 3" (TYP) 3 .. BASE SUPPORT BRACKET (TYP) CENTER STIFFENER SPOT WELD (TYP) SEE NOTE 3 HEREON ELEVATION VIEW N.T.S. ~--------"'L SECTION TOP 14GA5MM PERFORATED SCREEN50% OPEN NOTES: 1. ALL MATERIALS ARE TYPE 304SS UNLESS OTHERWISE NOTED 2. CENTER STIFFENER REQUIRED WHEN S 2: 3'-0 .. 3. CENTER STIFFENER WILL BE SPOT WELDED @ 4" C.C. (Max) TO PERFORATED SCREEN 4. EXTENSION PANELS USED FOR UNEVEN CATCH BASIN FLOOR 5. SCREENS LESS THAN 18" TALL WILL NOT INCLUDE A CHANNEL AT MID-HEIGHT . 66w 3/8" x 3 WEDGE ANCHOR, 2 PER CONNECTION (TYP) 5/16 .. X 1-1/8 .. HEX BOLT, WASHER, AND LOCK NUT (TYP) SECTION A-A N.T.S . L.06.oNOB.flOOOJlm'......::w.::illl(8 ·-□---IIOlEO 8 :mc,t.LCUlATIONI .50 ADS FLEXSTORM CPS U EXT *SEE APPENDIX APPENDIX A-1 AND CPS SIZING TABLE FOR Hb, Hs, & L VALUES VIEW N.T.S. VIEWN-N TOP AND BOTTOM SCREEN BEND PROFILE VIEWC-C PLAN, ELEVATION, AND DETAIL N.T.S. Mn 1f22f2020 !!H~ET 1 Cll' I -B D C B A Page | 15 •Hs 2" (Typ.) 0 0 Horizontal 1 /4" X 1/2" X 1/2" 12GA U-Channel Stiffener (Typ.) I •Hb 2" (Typ.) Vertical 1 1/4" X 1/2" X 1/2" 12GA U-Channel Stiffener (Typ.) ELEVATION VIEW N.T.S. R=10" (Typ.) I Spot Weld (Typ.) See Note 2 Hereon 1 1/2" X 1 1/2" 13GA Mounting Bracket (Typ.) --------14GA 5m m Perforated Screen 50% Open NOTES: 1. All Materials Are Type 304SS Unless Otherwise Noted 2. All Horizontal And Vertical Stiffeners Shall Be Spot Welded @ 4"C.C. (Max) To Perforated Screen 3. For Catch Basin Uneven Floor Extension Panel Detail See Sh. 3 3/8" X 3" Wedge Anchor, 2 Per Connection (Typ.) Ex. Catch Basin Wall 1 1/2" X 1 1/2" X "Hs" 13GA Mounting Bracket (Typ.) 3/4" (Typ } 14GA 5mm Perforated Screen 50% Open I I I I I I I 1 1/4" X 1/2" X 1/2" 12GA U-Channel Stiffener (Typ,) DETAIL A N.T.S. Ver!Jcal PLAN VIEW N.T.S. 1 1/4" x 1/2" x 1/2" 12GA U-Channel S iffener (Typ.) ....----..... / ,, I \ / \ 1 1/2" X 1 1/2" 13GA Mounting Bracket ---· ADS FLEXSTORM CPS U PLAN, ELEVATION, AND DETAIL All Materials Ive Type 304SS Unless Otherwise Noted 2 All Honzontal And Vertical Stiffeners Shall Be Spot Welded@ 4"C.C. (Max} To Perforated Screen 3 Center Stiffener Required When S 2: 3'-0" 4. Top And Center Base Support Brackets Required When S 2: 3'-0" 5. 3" Base Support Bracket At The In ecbon Point Required For All Units 6. For Catch Basin Uneven Floor Extension Panel Detail See Sh 4 ' ' (Typ.) [ 5/16" x 1· Hex Bolt, Washer, And Lock Nut, 2 Per Connection 3" Base Support\',..___ __ ...,(12" Center Base Support Bracket ("!YP ), Bracket (When S 2: 3'-0") 1 1/4" X 1/2" X 1/2" -/l.__ 12GA U-Channel\ i V i See Oetatl 0, Sh. 3 See Detail C, Sh 3 Top Support Bracket, See Sh. 2 ELEVATION VIEW NT.S 3/8" X 3" Wedge Anchor {Typ.) ----------•L __________ _,, PLAN VIEW N.T.S. Stiffener {Typ.) 1 I I 3/4" J..---'---l...:..---.1' (Typ.) ! 14GA5mm Perforated Screen 50% Open 1 1/2" x 1 1/2" x "Hs" 13GA Mounting Bracket (Typ.) See Detail A Hereon I 2" I (Typ.) 7 I I I ~318"x3" Ex. Catch I Wedge Anchor, Basin Wall 1 2 Per Connection DETAIL A N.T.S. I (Typ.) --' ADS FLEXSTORM CPSL PLAN. ELEVATION, ANO Page | 16 Appendix C. Extension Panel Work Instructions EXTENSION PANEL WORK INSTRUCTIONS Use a grinding wheel to cut the panel after scribing the pattern of the floor on the top portion of t he panel. Cut the pattern out and now reverse it for installation. Use provided S the extension panel to t he CPS. For Quick angle may be placed behind the sere ills more than a 2" gap. For standard ins t anchored into the floor To scribe the basin floor pattern onto the extension panel use a spacer or our scribing tool as show n. Run the tool along the basin floor with a marker scribing the contour on the top portion of the extension panel. Cut the line off w ith a portable cutoff grindi ng tool. Reverse the panel cut side dow n w hich should match the flooring contour perfectly. Install the tek screw s on the top portion of the extension panel connecting it to the main CPS screen. Page | 17 14GA 5mm Perforated Screen 50% Open Z" x 'Z' x 3--14GA5mm P"rforated Base Support Bracket Ex Catch Basin Floor A 7 EXTENSION PANEL WORK INSTRUCTIONS ELEVATION VIEW N.T.S. 1 Piece ExtenstOn Panel 14GA 5mm Perforated Screen 50%0pen 1 1/2" x 1 1/2" 13GA Mounting Bracket (Typ.) See Detail A, Sh. 1 (Typ.) Extension Pa~ Scribed To Conform To Catch Basin Floor 1 Piece Extension Panel 14GA 5mm Perforated Screen 500/. Open 3116" Self Drillng screw (Typ.) SECTION A-A N.T.S. 14GA 5rm1 Perforated Screen 50% Open Horizontal 1 114• x 1/2'" x 1/2" 12GA U.Channet Stiffener ADS FLEXSTORM CPS U EXTENSION PANEL DETAILS Page | 18 Appendix D. Photo Gallery Hinged Lid Installation Photos Page | 19 4lOSO'SFIEl.DPHOTOS llEFOlll •lld.AITUI MAJ,._'ltlUf,;Q Page | 20 Appendix E. Vector Control Drawing Showing Hinged Lid CPS HINGED LID FOR VECTOR CONTROL HINGED LID SHOWN IN OPEN POSmON (REMAINS IN OPEN POSmON ON ITS OWN) LID BRACKETS SEOJRED TO WALL WITH SS WEDGE ANCHORS STAINLESS STEEL HINGE WELDED TO LID AT EAQ-1 SUPPORT BRACKET = -Tin: IIWIGIO --c CPS CONNECTOR PIPE ~ A ~ ... -.:.:.. Page | 21 APPENDIX F. ADS CPS Load Testing ADS CPS LOAD TESTING Uniform water loading results in 54 lbs/sqft against a solid screen. Triangular load distribution over an 18" tall screen results in 94 lbs/sqft along the bottom edge and tapers off to zero at the very top of the screen. LA County has asked us to simulate this triangular load scenario as trash builds up along the bottom and blinds the lower portion of the screen. We used steel bundles of channel that measured 6" x 8" and weighed 18 lbs each. 3 bundles make up 1 sqft at exactly 54 lbs or 54 lbs /sqft If we orientate the bundles to create 2 rows each 8" tall side by side, then we can create an 8" tall load of 108 lbs/sqft by stacking 2 bundles high on the bottom and 54 lbs/sqft in a single layer on the top. This provides a fairly significant safety factor vs the real world triangular load distribution. We proceeded with this loading scenario on a 10' I ong continous screen in our U-Extended configuration. The screen is rolled on 2 ends and a 7' straight length results across the mid section at 12" spacing from the wall. We previously determined that the maximum straight length span for our screen is 42" before deflecting more than 1". Test 1: We anchored the 10' continuous screen on a concrete floor at both ends and added two support brackets at 40" spacing centered on the screen and anchored on the brick wall. We added the load stacking 2 bundles high on the bottom row and 1 bundle tall covering the entire screen and witnessed minimal deflection if any. We continued loading adding additional bundles to the bottom load and also having 2 people stand in the center of the screen witnessing minimal deflection less than 1/2". Test 2: We ran another test on our 2 pc screen using only one l-bracket behind the connector located in the center of the 10' long screen comprised of 2 separate 5' l -shaped screens. We duplicated the load scenario and once again saw no deflection. We captued the loading on video which can be found at these dropbox links .. https://www.dropbox.com/s/vaqz52zoacxsiie/Video%20Mar°/o2008%2C%203%2002%2053%20P M. mov?dl=0 https://www.dropbox.com/s/ysrtl 1 wa nyhzzqg/Video%20Mar%2008%2C%202%2043%2043%20PM .mov?dl=0 TEST 2 VIDEO TEST 1 VIDEO Page | 22 ADS CPS DEFLECTOR LOAD TESTING U-BEND FRONT EDGE WITH 36" SUPPORT BRACKET SPACING Wt continued ttstin& with I ntw dtfkctor that included a U bend on the front edct. 1" drop i nd 1/2• bend under. The center1ine spacing on the Support Brackets was once again 36". The results were quite conclusive a.sour 22S lb test load (worker) wu a bit to Jump up and down on 1 foot at tdgt for scrttn without 1ny deformation. Wt propose all deflectors will include tM double bend on outer front ed;e for the continous lellJth. No Edge Stiffener is required. We are asking for a callout allowing 36" Max Allowabte Spacing between any 2 Support Bru'kets.