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17-105489-Preliminary Technical Information Report-12-21-2023Woodbridge Business Park Preliminary Technical Information Report December 7, 2023 Prepared for Federal Way Campus, LLC 11100 Santa Monica Blvd., Suite 850 Los Angeles, CA, 90025 (310) 261 - 4382 Submitted by ESM Consulting Engineers, LLC 33400 8th Avenue S, Suite 205 Federal Way, WA 98003 253.838.6113 tel 253.838.7104 fax www.esmcivil.com 12/07/2023 Table of Contents Section 1. Project Overview Section 2. Conditions and Requirements Summary Section 3. Off-Site Analysis Section 4. Flow Control & Water Quality Facility Analysis and Design Section 5. Conveyance System Analysis and Design Section 6. Special Reports and Studies Section 7. Other Permits Section 8. ESC Analysis and Design Section 9. Bond Quantities, Facility Summaries, & Declaration of Covenant Section 10. Operations and Maintenance Manual List of Figures 1.1 Vicinity Map 1.2 Existing Site Conditions 1.3 Proposed Site Conditions 1.4 Soils Map 3.1 Site Topography 3.2 Downstream Analysis Flow Path Appendix A Developed Basin Map B Hydrology Model Output C Woodbridge Business Park TIR Addendum \\esm8\engr\esm-jobs\1886\001\016-0016\stormreport\documents\rprt-001 - 2023-01-04.docx 1. Project Overview The purpose of this report is to encapsulate the documents and analysis required by the Full Drainage Review in the 2021 King County Surface Water Design Manual (SWDM). Existing Site: The proposed Woodbridge Business Park project site is located in the NE and SE quarters of Section 16, Township 21 North, Range 04 East, W.M. in the City of Federal Way, WA. More specifically, the project site is located on the west side of Weyerhaeuser Way S between S 336th Street & S 323rd Street. The project will include 3 parcels on 97.66 acres (162104-9030,162104-9013, and 162104-9056) zoned as CP-1 and will be developed in accordance with the applicable City of Federal Way code. Additionally, the property is subject to the Concomitant Pre-Annexation Zoning Agreement dated August 23, 1994. See Figure 1.1 for a vicinity map and Figure 1.2 for the existing site conditions. Existing Site Hydrology: The existing site is partially developed with a commercial building and associated parking lots, outbuildings, paved driveways, and landscaped areas. The remainder of the site is predominantly forest with some pasture. The property slopes gently to the south and east at 0 - 8%. Stormwater runoff generally drains south to S 336th Street and into the existing stormwater drainage system. A portion of the site (approximately 24 acres) drains to the Weyerhaeuser Way S and is estimated to outfall to North Lake. There is an existing Sphagnum Bog located adjacent to the northwest corner of the project site (approximate onsite portion of the drainage basin is 2 acres). The site is located in the Hylebos Creek drainage basin (WRIA number: 10). See Section 3 for more information. Proposed Site Improvements: The proposed development includes the demolition of existing parking lots, clearing, grading, and the construction of 3 new commercial buildings with parking lots, access roads, utility services, and stormwater facilities on 72.99 acres (71.48 acres detention mitigated area & 1.51 acres dispersed pervious area) as well as the associated frontage improvements along Weyerhaeuser Way S. Figure 1.3 illustrates the Proposed Site Conditions and Section 4 describes in more detail the proposed developed areas. Proposed Site Hydrology: The proposed onsite stormwater conveyance system will collect and convey runoff from the developed project site to the stormwater drainage system in the Right-of-Way (ROW) of S 336th Street and Weyerhaeuser Way S. The developed site has been designed such as to direct all proposed impervious areas to detention and water quality treatment facilities. Specifically, the pollution generating impervious area at the NW corner has been designed to discharge to Pond 2. All proposed impervious areas within the developed project site will drain to the south and east boundaries of the site, discharging to the Weyerhaeuser Pond and North Lake respectively, which are the natural discharge locations for the site. See Sections 4 and 5 of this report for more information. Stormwater Runoff Mitigation Standard: The proposed development will comply with Level 2 Flow Control, Basic and Enhanced Water Quality Treatment per the SWDM. See Section 4 for more information. Soils on the Project Site: The Soils Map and Geotechnical Engineering Report indicate the soils onsite include Alderwood gravely sandy loam, 0 - 8% slopes. See Figure 1.4 and the Geotechnical Engineering Report included under separate cover for more information. Flow Control BMP’s: All applicable Flow Control BMP’s are listed and explained in Section 4 of this report. n INT E R S T A T E 5 WEYERHAEUSER WAY S WEYERHAEUS E R W A Y S S 3 3 6 T H S T R E E T L L CFederal Way, WA 9800333400 8th Ave S, Suite 205C O N S U L T I N G E N G I N E E R SFEDERAL WAY CAMPUS, LLCWOODBRIDGE BUSINESS PARKSCALE: 1" = 300' FIGURE 1.2 S 3 3 6 T H S T WEYERH A E U S E R W A Y S . n SCALE: 1" = 100'C O N S U L T I N G E N G I N E E R SL L CFederal Way, WA 9800333400 8th Ave S, Suite 205FEDERAL WAY CAMPUS LLCWOODRIDGE BUSINESS PARKEN-43 1 1 INTE R S T A T E 5 POND 2 DETENTION VAULT 1 DETENTION POND 3 DETENTION POND 4 DETENTION POND 5 DETENTION LEGEND BUILDING "1" ±605,200 SF FF=VARIES 442.38-448.45 BUILDING "2" ±240,700 SF FF=VARIES 420.28-424.53 FUTURE BUILDING "3" ±125,500 SF FF=VARIES 422.13-424.50 EXISTING WTC BUILDING FF=437.00 Soil Map—King County Area, Washington (95 Acre Short Plat) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/6/2016 Page 1 of 352391005239200523930052394005239500523960052397005239800523990052400005239100523920052393005239400523950052396005239700523980052399005240000552600552700552800552900553000553100553200553300553400553500553600553700553800553900554000 552600 552700 552800 552900 553000 553100 553200 553300 553400 553500 553600 553700 553800 553900 554000 47° 18' 41'' N 122° 18' 18'' W47° 18' 41'' N122° 17' 7'' W47° 18' 10'' N 122° 18' 18'' W47° 18' 10'' N 122° 17' 7'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 300 600 1200 1800 Feet 0 100 200 400 600 Meters Map Scale: 1:6,840 if printed on A landscape (11" x 8.5") sheet. Warning: Soil Map may not be valid at this scale. MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography 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: http://websoilsurvey.nrcs.usda.gov 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: King County Area, Washington Survey Area Data: Version 11, Sep 14, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 8, 2014—Jul 15, 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. Soil Map—King County Area, Washington (95 Acre Short Plat) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/6/2016 Page 2 of 3 Map Unit Legend King County Area, Washington (WA633) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgB Alderwood gravelly sandy loam, 0 to 8 percent slopes 104.7 99.6% AgC Alderwood gravelly sandy loam, 8 to 15 percent slopes 0.4 0.4% Totals for Area of Interest 105.1 100.0% Soil Map—King County Area, Washington 95 Acre Short Plat Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 10/6/2016 Page 3 of 3 2. Conditions and Requirements Summary Review of the 9 Core Requirements and 5 Special Requirements This section describes how the project will meet the SWDM Core and Special Requirements. Core Requirement No. 1 Discharge at the Natural Location Stormwater runoff generated from the developed project site is estimated to drain south and east to the S 336th Street and Weyerhaeuser Way S, respectively. From there, runoff is conveyed to North Lake and to Stream AC, which are the natural discharge locations for the project site. Core Requirement No. 2 Off-site Analysis The off-site and downstream analyses are documented in Section 3 of this report. Core Requirement No. 3 Flow Control Level 2 Flow Control is required per the pre-application meeting notes for this project, which will be met by proposed detention vault, ponds, and storage in the existing Weyerhaeuser Pond. See Section 4 of this report for more information. Core Requirement No. 4 Conveyance System Stormwater conveyance will be provided for the proposed and existing conveyance systems per Section 5 of the SWDM. Calculations will be provided in the final TIR. Core Requirement No. 5 Erosion and Sediment Control Erosion and sediment controls to prevent the transport of sediment from the project site to downstream drainage facilities, water resources, and adjacent properties will be provided on the construction plans. Core Requirement No. 6 Maintenance and Operations The Operations and Maintenance manual will be included with the final TIR. Core Requirement No. 7 Financial Guarantees and Liability All drainage facilities constructed or modified for projects will comply with the financial guarantee requirements as provided in the King County Bond Quantities Worksheet. Bond Quantities will be provided in the final TIR. Core Requirement No. 8 Water Quality Basic and Enhanced Water Quality Treatment is required per the pre-application meeting notes and will be provided as described in Section 4. Core Requirement No. 9 Flow Control BMP’s All applicable Flow Control BMP’s are listed and discussed in Section 4 of this report. Special Requirement No. 1 Other Adopted Area-Specific Requirements There are no master drainage plans, basin plans, salmon conservation plans, stormwater compliance plans, flood hazard reduction plan updates, or shared facility drainage plans for this project. Special Requirement No. 1 does not apply. Special Requirement No. 2 Flood Hazard Area Delineation The developed project site location is not in a 100-year floodplain. Special Requirement No. 2 does not apply. Special Requirement No. 3 Flood Protection Facilities The developed project site is not protected by an existing flood protection facility. The proposed site improvements do not include the modification of an existing flood protection facility. Special Requirement No. 3 does not apply. Special Requirement No. 4 Source Control The project will follow the King County Stormwater Pollution Prevention Manual and King County Code 9.12 to identify and implement source controls as needed. Due to the proposed use of the project site, source control is not required; therefore, Special Requirement No. 4 does not apply. Special Requirement No. 5 Oil Control The proposed development is commercial and (according to the definition provided in the SWDM), portions of the project site qualify as a “high-use site” due to vehicle fleet size; therefore, Special Requirement No. 5 does apply. Implementation details regarding oil control will be provided in the final TIR. 3.Off-Site Analysis A Level 1 downstream analysis has been performed for the site. Task 1: Study Area Definition and Maps The study area consists of the project site and 1/4 mile downstream flow path for runoff released from the existing site. See Figure 1.2 and Figure 3.2 for the Existing Site Conditions and Downstream Analysis Flow Path exhibits. Task 2: Resource Review Flow Control Map According to the pre-application meeting notes, the project is required to comply with Level 2 Flow Control criteria. Soil Survey Map Web Soil Survey maps the soils onsite include Alderwood gravely sandy loam, 0 - 8% slopes. Refer to the Geotechnical Engineering Report attached under separate cover for more detail. King County iMap According to iMap, the project site is NOT mapped in any of the following areas: - Landslide Hazard area - Coal Mine Hazard Areas - Erosion Hazard area - 100 Year Floodplains - Critical Aquifer Recharge Area - Seismic Hazard area King County iMap and the Pre-Application Conference Notes The project site has the following areas mapped onsite and nearby: - Streams & Wetlands See Figure 3.1 for more information regarding the environmental hazards near the project site. Road Drainage Problems None noted Wetlands Inventory According to iMap, the Critical Areas Review, and the 1990 King County Wetlands Inventory Notebooks there are no recorded wetlands on the existing project site. However, the wetland biologist has located onsite wetland areas and there are wetland areas downstream of the developed project site. See Figure 1.2 for Existing Site Conditions and the wetland report for more information. Migrating River Study None noted Downstream Drainage Complaints According to iMap, there are no relevant downstream drainage complaints within the scope of this project. Task 3: Field Inspection (Level 1 Inspection) A Level 1 Downstream Analysis was completed by ESM Consulting Engineers, LLC in the early afternoon on October 5, 2016, when it was sunny and 65°F. During the inspection it was found that the project site has no apparent upstream offsite areas draining to the property. Stormwater runoff from the existing site’s lawn, vegetated areas, roof, roads, access ways, and parking lot is estimated to flow across the property to the south and east boundaries of the site and drain to the public ROW. From there, stormwater runoff south of the site’s existing south entrance is collected in the gutter along the west side of Weyerhaeuser Way S and continues south to S 336th Street. The runoff is conveyed in a piped system or via roadside ditch in the area near the roundabout. Once past the roundabout, the runoff crosses under S 336th Street in two 12-inch diameter concrete culverts and continues to the Weyerhaeuser Pond via established drainage paths. Stormwater runoff north of the site’s existing south entrance is estimated to be collected in a roadside ditch and conveyed east under Weyerhaeuser Way S to North Lake via two culvert pipes. There did not appear to be any flooding issues over any of the roadways adjacent to, and downstream of, the project site. See Figure 3.2 Downstream Analysis Flowpath for further information and the approximate existing basin area draining to North Lake. The site was revisited around noon on January 18, 2017, when it was heavily raining. Following the flow of stormwater south of S 336th Street, stormwater was routed in a drainage ditch with no apparent restrictions on its way to the Weyerhaeuser Pond. The flow increased significantly once it was joined with the outflow from North Lake. At that point it appeared that the capacity of the drainage ditch was increased sufficiently to convey the stormwater runoff. The site was revisited around 3:00pm on May 26, 2021, when it was sunny and 70°F in order to document an existing culvert near the northern site boundary conveys stormwater from the site to North Lake (at Point 1A on Figure 3.2 in this section of the report). That culvert was not visible at the time of the site visit, most likely due to ground cover and duff build up over time; therefore, no pictures are included. Task 4: Drainage Description and Problem Descriptions According to iMap, the project site is in the Hylebos Creek (King County WRIA number: 10) drainage basin. Hylebos Creek is located approximately 0.3 miles to the west of the project and separated by I-5. No drainage problems are known to exist in the site’s present condition. There is an existing Sphagnum Bog located adjacent to the northwest corner of the project site (parcel 215465-0170). The onsite portion of the Sphagnum Bog drainage basin is 2 acres of which 0.2 acres will be developed as part of this project and 1.8 acres will be developed as part of the future South 324th Street Extension. There are no drainage problems known for the Sphagnum Bog. Task 5: Mitigation of Existing or Potential Problems No existing or potential problems were observed with the existing drainage system within the scope of the downstream analysis. Therefore, no further mitigation is proposed. - Date: 10/7/2016 Notes: The information included on this map h as been compiled by King County sta ff from a varie ty of sources and is subject tochange without notice. King County makes no representations or warrantie s, express or implied, as to accuracy,completeness, timeliness, or rights to the use of such information. This document is not inten ded for use as a surveyproduct. King County shall not be liab le for any general, special, indirect, incidental, or consequential damages including,but not limited to, lost revenues or lost p rofits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on th is map is prohibited except by written permission of King County. Le gend Parcels Bonde d Commercial -MF Commercial -SF Construction DOT FM D Region al Residential Drain age comp lai nts Potential land slidehazard a rea s (2016,see explan ation--->) Potential stee p slop ehazard a rea s (2016,see explan ation--->) Erosion haza rd (199 0SAO) Sei smic h azard (1 990SAO) Coal mi ne h azar d(19 90 SAO) cl ass 1 cl ass 2 perennia l cl ass 2 salmo nid cl ass 3 uncla ssified Wetland (1990 S AO ) Sensitive area noticeon title - Date: 10/5/2016 Notes: The information included on this map has been compiled by King County staff from a variety of sources and is subject tochange without notice. King County makes no representations or warranties, express or implied, as to accuracy,completeness, timeliness, or rights to the use of such information. This document is not intended for use as a surveyproduct. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including,but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map.Any sale of this map or information on this map is prohibited except by written permission of King County. Legend Parcels Streams Point 1: Looking south, east (across the road), and at the culvert inlet. Stormwater collected in the roadside ditch is conveyed to this culvert on the west side of Weyerhaeuser Way SW where it crosses the road and continues east to North Lake. Culvert Point 2: Looking south on the west side of Weyerhaeuser Way SW Water from the site that flows to Weyerhaeuser Way SW is routed to this culvert via roadside ditch and continues east. Looking north on the east side of Weyerhaeuser Way SW Point 3: Looking north on the west side of Weyerhaeuser Way SW. Stormwater runoff south of the south entrance to the existing site is collected by this roadside ditch. Point 3: Looking south on the west side of Weyerhaeuser Way SW. From the ditch, stormwater enters the existing stormwater conveyance system in this culvert. Point 3: Looking south toward the roundabout. Stormwater runoff not collect further north is collected by this ditch along the south boundary of the site and drains to Point 4. Point 4: Looking south at the inlet of the pipes crossing S 336th Street. Point 5: Looking west on the south side of S 336th Street where the stormwater runoff from the project site crosses and drains to Weyerhaeuser Pond. 4. Flow Control & Water Quality Facility Analysis and Design Existing Site Hydrology: The existing site is partially developed with a commercial building and associated parking lots, outbuildings, paved driveways, and landscaped areas. The remainder of the site is predominantly forest with some pasture. The property slopes gently to the south and east at 0 - 8%. Stormwater runoff generally drains south to the S 336th Street public ROW and into the existing stormwater drainage system. A small portion of the site drains east to the Weyerhaeuser Way S and is estimated to outfall to North Lake. The site is located in the Hylebos Creek drainage basin (WRIA number: 10). See Section 3 for more information. Due to the topography of the project site, the existing 5 onsite basins shown in Figure 1.3 drain to the south and east borders. From there, Basin 1 stormwater runoff is conveyed to North Lake (POC A) and runoff from Basins 2-5 continue to the Weyerhaeuser Pond (POC B), which are therefore the Points of Compliance for the project. As required by the SWDM, the existing basins have been modeled as pre-developed forested, and the areas are described in Table 4.0 below (totaling 70.59 acres). Table 4.0 Land Use ( Acres ) Basin 1(incl. Bypass) Basin 2 (incl. Bypass)Basin 3 Basin 4 Basin 5 (incl. Bypass) C, Forest 11.16 + 0.52 22.47 + 0.36 16.10 6.27 13.85 + 0.75 Developed Site Hydrology: The developed Basins 1-5 (totaling 71.48 acres) are generally described below, shown in Table 4.1, and illustrated on the Developed Basin Map in Appendix A. Basin 1 (POC A) The proposed drainage Basin 1 consists of 11.16 acres of developed area. This area discharges in the same direction as the existing 24-acre drainage basin that drains to the wetlands and associated buffers on the east side of Weyerhaeuser Way S and continues to North Lake, which is the natural discharge location for the basin. The developed area includes the eastern portion of the proposed Building 1, associated standard parking and landscaped areas, and the proposed Vault 1 area. A small 0.52-acre portion of Basin 1 drains directly to Weyerhaeuser Way S and will bypass Vault 1, which has been modeled as bypass in WWHM. Together, all of these areas are approximately equal to the existing basin that is tributary to North Lake. Basin 1 also contains 0.2 acres of developed area that is 10% of the existing onsite portion of the Sphagnum Bog drainage basin adjacent to the northwest corner of the project site. This area is considered a negligible contribution to the Sphagnum Bog and is not anticipated to impact hydrology. Furthermore, the remaining undisturbed 1.8 acres of the onsite portion of the Sphagnum Bog drainage basin will be developed with the future South 324th Street Extension. Refer to Figure 1.2 & Figure 1.3 in Section 1 of this report for more information regarding the North Lake basin area existing and proposed area equivalence. Basin 2 (POC B) The proposed drainage Basin 2 consists of 22.48 acres of developed area. This area discharges to the wetlands and associated buffers on the east side of Interstate 5 and continues to Stream AC, which continues south to the Weyerhaeuser Pond, which is the natural discharge location for the basin. The developed area includes the western portion of the proposed Building 1, associated truck and standard parking lot areas, relocated Tech Center parking lot areas, landscaped parking lot areas, and the proposed Pond 2 area. A small 0.36-acre portion of Basin 2 drains directly to Weyerhaeuser Way S and will bypass Pond 2, which has been modeled as bypass in WWHM. All other proposed impervious surfaces will be collected and routed to the flow control and water quality treatment facility for Basin 2. The pond for this basin was reconfigured to be outside of the meadow and its associated view corridor. Basin 3 (POC B) The proposed drainage Basin 3 consists of 16.10 acres of developed area. This area discharges to Stream AC, which continues south to the Weyerhaeuser Pond, which is the natural discharge location for the basin. The developed area includes Building 3 roof runoff, standard parking lot area, land scaped area, as well as the proposed Pond 3 area. The pond for this basin was reconfigured to be outside of the meadow and its associated view corridor. Basin 4 (POC B) The proposed drainage Basin 4 consists of 6.27 acres of developed area. This area discharges to Stream AC, which continues south to the Weyerhaeuser Pond, which is the natural discharge location for the basin. The developed area includes truck and standard parking lot areas associated with Building 3, landscaped parking lot areas and the proposed Pond 4 area. Basin 5 (POC B) The proposed drainage Basin 5 consists of 13.85 acres of developed area. This area discharges to Stream AC, which continues south to the Weyerhaeuser Pond, which is the natural discharge location for the basin. The developed area includes Building 2, associated truck and standard parking lot areas, landscaped parking lot areas, and the proposed Pond 5 area. A small 0.75-acre portion of Basin 5 drains directly to Weyerhaeuser Way S and will bypass Pond 5, which has been modeled as bypass in WWHM. Table 4.1 Land Use (Acres) Basin 1 Basin 2 Basin 3 Basin 4 Basin 5 Total Dev By pass Dev By pass Dev Dev Dev By pass Pond (Lawn)0.00 0.00 2.09 0.00 1.64 0.76 0.93 0.00 5.42 Lawn 0.81 0.52 1.11 0.03 1.42 0.37 1.57 0.24 6.07 Road 5.46 0.00 10.25 0.33 5.91 3.89 5.82 0.51 32.17 Roof 4.89 0.00 9.02 0.00 7.13 1.25 5.53 0.00 27.82 Basin Total 11.16 0.52 22.47 0.36 16.10 6.27 13.85 0.75 71.48 The frontage improvements along the majority of both sides of Weyerhaeuser Way S consist of approximately 5.5 acres of ROW dedication, 3.07 acres of asphalt pavement, 1.7 acres of sidewalk, and 0.73 acres of landscaping. The northern portion of the existing roadway and associated frontage improvements discharges in the same direction as the existing 24-acre drainage basin that drains to the wetlands and associated buffers on the east side of Weyerhaeuser Way S and continues to North Lake. The remaining portion of the existing roadway and associated frontage improvements flows southeast to the Weyerhaeuser Pond, which is the natural discharge location for the basin. Per Section 1.1.2.5 of the SWDM, the project is not an Urban Planned Development (UPD). Additionally, the project proposes 32.17 acres of road area, 27.82 acres of roof area, and 3.14 acres of impervious frontage area (1.87 acres new asphalt pavement + 1.27 acres new sidewalk), which totals 62.90 acres of impervious area. In addition, Weyerhaeuser Way South will require pavement reconstruction for an additional 5.91 acres of replaced impervious asphalt area. Removing 10.84 acres of the replaced impervious area onsite and 7.75 acres of existing impervious area onsite to remain, the total new onsite and frontage impervious area is 44.31 acres. This new impervious area is less than 50 acres and is not in a critical aquifer recharge area; therefore, large project drainage review is not required. Performance Standards: Stormwater systems onsite are to be designed to mitigate runoff generated from the project per the requirements of the SWDM, specifically the Conservation Flow Control (Level 2) standards in Section 1.2.3.1.B. The facility size is required to be determined by an approved hydrology model per the SWDM. The existing building and areas to remain will be retrofitted to meet the Level 2 Flow Control standard. The approved hydrology model used to size the stormwater detention and water quality facilities was the 2012 Western Washington Hydrology Model (WWHM). The Hydrologic Simulation Program Fortran (HSPF) is the computation software that is executed from within WWHM to perform the continuous runoff stormwater modeling. Due to the size and location of the proposed development, the project is required to comply with Conservation Flow Control (Level 2) standards. There are no anticipated adverse downstream impacts under the Level 2 standards; however, the project has voluntarily elected to comply with the more stringent Level 3 Flow Control standards with additional factor of safety in the detention volume provided. Level 3 Flow Control standards (defined under Level 3 on page 3-6 of the 2021 SWDM) states: Level 3 Flow Control … This standard requires maintaining the durations of high flows at their predevelopment levels for all flows greater than one-half of the 2-year flow up to the 50-year flow and holding the 100-year peak flow rate at its predevelopment level. The predevelopment peak flow rates for the 2-year and 10-year runoff events are also intended to be maintained when applying Level 3 flow control. Those flow control requirements are estimated to be met with stormwater detention facilities, as described in this section under Flow Control System. Furthermore, this project is subject to compliance and consistency with the 1991 Basin Plan. There were no requirements imposed specifically on the project site, but the basin-wide requirements are applicable for subcatchment H8 (which contains the project site) shown on Figure 2.3.2 of the Basin Plan. The indicated priority for development in the higher subcatchment areas of the East Branch Hylebos Creek Sub-Basin are flow control mitigation to prevent further scouring of the ravine that conveys stormwater runoff down through Milton. The most stringent flow control criteria within the Basin Plan (defined under BW-3 on page 3-6 of the 1991 Basin Plan) states: BW-3:Stream Protection Onsite Detention Standard In subcatchments where future flows are expected to have significant adverse impacts on stream stability and habitat, onsite detention ponds for new development, including public and private streets and highways, should be designed such that post- development flow peaks and durations are reduced to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year. In addition, the 100-year post-development peak flow should be reduced to the 100-year pre- development level. The recommended method of designing these detention ponds is a calibrated continuous hydrologic model, preferably HSPF. HSPF (as noted above) is used by WWHM in the current approved hydrology model and is the preferred method per the Basin Plan. The BW-3 standard is nearly identical to the modern Level 3 Flow Control mitigation standard defined in the current SWDM, except that Level 3 allows the 100-year peak flow rate target to be calculated from the existing site conditions. Instead, for this project site the 100-year peak flow rate target will be conservatively calculated from pre-developed (forest) conditions. The newer standard also requires that the developed condition 2-year & 10-year peak flows more conservatively match the pre-developed (forested) condition 2-year & 10- year peak flows. To meet the intent of this flow rate matching standard, the project will conservatively release stormwater at rates that are strictly less than the pre-developed flow rates for the given return periods. Due to the type of development being commercial, the required water quality treatment standard is Enhanced Basic WQ treatment per Section 1.2.8.1.A of the SWDM. Those treatment requirements are estimated to be met with a proprietary treatment system, as described in this section under Water Quality System. Enhanced Basic WQ treatment standards per the 2021 SWDM are compliant and consistent with the 1991 Basin Plan. Flow Control System: The approved hydrology model used to size the detention portion of Vault 1 & Ponds 2-5 (to match the basin numbering) was the Western Washington Hydrology Model (WWHM) version 2012. The default sizing from that software complies with the Level 2 Flow Control standards. As modeled in WWHM, Basins 2 and 5 mitigated developed flows include flows that bypass the respective stormwater flow control mitigation facilities. Detention facility 1 (in Basin 1) has been shown in the model (Model A) to comply with Level 3 Flow Control standards (which meets Level 2 and exceeds by matching 100-year peak flows). Detention facilities 2 through 4 (in Basins 2 through 4) have been shown in the model (Model B, both separately and together) to comply with Level 3 Flow Control standards. Detention facility 5 (in Basin 5) has been shown in the model (Model B) to comply with Level 3 Flow Control standards (both independently and together with Basins 2 through 4) and then modeled separately (Model C) with the proposed final graded pond volume where the remainder of the required detention volume is sent to the Weyerhaeuser Pond (see below for full description). The pre-developed and developed project site mitigated flow rates are given in Table 4.2 and comply with Level 2 Flow Control standards. The estimated volumes required and provided are given in Table 4.3. The WWHM output is provided in Appendix B. Table 4.2 Peak Flows (cfs) Basin 1 Model A POC 1 Basin 2 Model B POC 2 Basin 3 Model B POC 3 Basin 4 Model B POC 4 Basin 5 Model C POC 5 Return Period Pre Dev Mit Pre Dev Mit Pre Dev Mit Pre Dev Mit Pre *Dev Mit 2 Year 0.343 0.224 0.671 0.480 0.473 0.260 0.184 0.094 0.407 1.224 5 Year 0.539 0.330 1.054 0.704 0.743 0.358 0.290 0.136 0.640 2.101 10 Year 0.650 0.411 1.271 0.881 0.896 0.434 0.349 0.169 0.771 2.803 25 Year 0.768 0.526 1.501 1.135 1.059 0.543 0.412 0.219 0.911 3.831 50 Year 0.841 0.621 1.643 1.349 1.159 0.634 0.451 0.262 0.997 4.699 100 Year 0.903 0.725 1.764 1.587 1.244 0.734 0.485 0.310 1.070 5.656 * Further mitigation provided by the Weyerhaeuser Pond. Table 4.3 Stormwater Detention Volume (acre-feet) Vault 1 Pond 2 Pond 3 Pond 4 Pond 5 Required 5.37 9.25 6.84 2.67 5.57* Provided 5.55 9.32 7.08 2.82 1.72 Additional Safety Factor 3%1%3%5%N/A *3.85 acre-feet to Weyerhaeuser Pond The Pond 5 flow control system has been sized to meet Level 3 flow control standards to determine the minimum detention volume necessary for mitigation. That volume was then reduced by 3.85 acre-feet (see below for explanation) and the resulting pond has a new control structure to attenuate the peak flows to the maximum extent practicable while sending the remainder to the Weyerhaeuser Pond for mitigation. In the proposed configuration, the Pond 5 control structure will have 1 orifice sized to release the 2-year peak flow near the top of the riser and the 100-year peak flow will occur at 0.43-feet over the riser. Refer to Section 5 of this report for more information on Pond 5 flow computations. The Weyerhaeuser Pond’s head`works were modified and approved in July of 2004 to increase the live storage by 200,000 cubic feet (4.59 acre-feet). The pond’s weir was adjusted 9 inches in height to obtain this additional live storage. This project preliminarily proposes to discharge 167,706 cubic feet (3.85 acre-feet) of additional live storage from Pond 5 to the Weyerhaeuser Pond, to use the available additional live storage. The existing surveyed water edge has an area of 351,379 square feet (8.07 acres), which results in an increase of ponding depth to the Weyerhaeuser Pond during the 100-year storm event is approximately 0.477-feet (5.7 inches). This increase in volume and associated ponding depth is acceptable because it is less than the design capacity of the previous adjustment. Flow control for the proposed frontage improvements will be provided as feasible in the existing and dedicated right-of-way areas in relocated roadside swales, matching the drainage flow paths for the existing pavement, with additional detention capacity in the Weyerhaeuser Pond. Detailed flow control analysis will be completed with the final frontage improvement plans, which will also require relocating existing utility infrastructure, extending existing culverts, as well as new pavement channelization. Water Quality System: The approved hydrology model used to size Vault 1 & Ponds 2-5 was WWHM version 2012. A Modular Wetlands System (MWS) or approved equivalent treatment facility precedes detention in Basin 1 and Basin 5. Due to the MWS’s internal bypass system, WWHM’s offline water quality flow rate was used to size these units. MWS treatment facilities are located downstream of the Basin 2, 3, and 4 detention facilities and were sized with the 2- year mitigated flow rate for each basin area. MWS treatment meets the Enhanced Water Quality Treatment standards in Section 1.2.8 of the SWDM. Oil control is required for the parking lot areas with expected heavy vehicle traffic, further details for oil control will be provided in the final report. The required treatment rates are given in Table 4.4. The WWHM output is provided in Appendix B. Further details on the Modular Wetlands System will be provided in the final report. Table 4.4 Water Quality Flow Rate (cfs) Basin 1 Model A POC 1 2-year Basin 2 Model B POC 2 2-year Basin 3 Model B POC 3 2-year Basin 4 Model B POC 4 2-year Basin 5 Model C POC 6 Offline Required 0.224 0.480 0.260 0.094 0.526* Vault Model (MWS)8-8 8-20 8-12 4-8 8-20 * The MWS for Basin 5 precedes detention and therefore is sized with WWHM’s offline WQ flow rate on the PGIS only. Due to the overall size of the building roof, stormwater tributary to Pond 5 from pollution generating impervious surfaces will be treated prior to detention. The building roof will be routed directly into the pond to bypass water quality treatment facility. This treatment system placement for Pond 5 yields a smaller water quality treatment facility requirement than with the facility downstream of detention when Pond 5 is configured to send 3.85 acre-feet to the Weyerhaeuser Pond. Water quality treatment for the new and replaced pollution generating impervious areas of the proposed frontage improvements will be provided with Modular Wetlands filter vaults or approved equivalent treatment that meets the Enhanced Basic WQ treatment standards per the 2021 SWDM or those treatment options that meet the Enhanced Basic Treatment criteria and have General Use Level Designation (GULD) by the Washington State Department of Ecology and are compliant and consistent with the 1991 Basin Plan. Flow Control BMPs Flow control BMPs have been preliminarily evaluated for the project site as outlined in the SWDM under Section 1.2.9.2.2 – Large Lot BMP Requirements. These BMP’s are described below in the required order, with feasibility determined and the portion of applicable area credited as mitigated, which should be no less than 10% of the total site area – 7.19 acres. Full Dispersion There are multiple native vegetated areas surrounding the project site that will be left undisturbed. The areas on the east side of the project site are not large enough to accommodate a minimum flowpath of 100 feet in length. The areas on the west side of the project site consist mostly of wetlands, streams and associated buffers and are not feasible for full dispersion. The areas on the north side of the project site are upstream, thus also not feasible for full dispersion. In summary, Full Dispersion is infeasible for this project site. Full Infiltration The Geotechnical Engineering Report states that “…there is very limited infiltration potential at this site. Because of these factors we recommend that stormwater detention be used for site development.” Because of this recommendation, Full Infiltration (specified in Section C.2.2.2.1) minimum requirements cannot be met; hence, Full Infiltration is infeasible for this project site. Limited Infiltration Limited Infiltration (specified in Section C.2.3) has the same minimum design requirements as Full Infiltration. Since Full Infiltration has been deemed infeasible, Limited Infiltration is also infeasible for this project site. Bioretention According to the geotechnical memo (included in Appendix C of this report), there is insufficient infiltration onsite to facilitate a 24-hour maximum draw-down time per C.2.6.1.4; therefore, Bioretention (specified in Section C.2.6) is infeasible for this project site. Permeable Pavement This project site is defined as a “high-use site”; therefore, according to Section C.2.7 (criterion 27) of the Permeable Pavement Infeasibility Criteria List, Permeable Pavement is infeasible for this project. Basic Dispersion As discussed above for Full Dispersion, the native vegetated areas are deemed to be infeasible for Basic Dispersion. If the impervious area credited as mitigated is less than the threshold specified in Flow Control BMPs above, then (according to Section 1.2.9.2.2.5 of the SWDM) a fee in lieu must be paid OR one or more the following BMPs must be implemented to achieve compliance: Reduced Impervious Surface Credit This project is larger than 250,000 square feet (Section C.2.9.2), cannot use wheel strip driveways (Section C.2.9.3) due to the proposed parking layout, cannot implement a minimum disturbance foundation (Section C.2.9.4) due to the building type, and open grid decking over pervious surface (Section C.2.9.5) is not applicable. Therefore, minimum design requirement #1 (specified in Section C.2.9.1) cannot be met; hence, the Reduced Impervious Surface Credit cannot be claimed for the proposed site improvements. Native Growth Retention Credit The minimum design requirement that any area of target impervious surface credited as mitigated by this credit must be directed to vegetated pervious areas on the site or discharged through a perforated pipe connection in accordance with Section C.2.11. While it is not feasible to direct stormwater runoff to those surfaces due to the elevation difference of the applicable vegetated pervious areas, the perforated pipe connection will be provided to the roof downspouts for the three proposed buildings. Out of the total parcel area (97.66 acres), the undisturbed native vegetation area of 26.41 acres mitigates for 7.54 acres of impervious area, which is equivalent to 11% of the total project site area (71.48 acres) and 13% of the total impervious area (59.76 acres). The native vegetated area used for this credit requires specific covenants, per SWDM, and these requirements have been preliminarily compared with the Weyerhaeuser Company Concomitant Pre-Annexation Zoning Agreement (CZA). The requirements in the SWDM appear to not conflict with the CZA, therefore, native growth retention appears to be feasible for the project site and will be confirmed with final design. Soil Amendment Minimum Requirement #6 All new pervious surfaces will be amended per Section 1.2.9.2.2.6 of the SWDM to satisfy the requirements specified therein (notes will be added on the final landscape plans). Roof Downspout Minimum Requirement #7 All roof downspouts will be shown on the final construction plans to connect to the storm system via Perforated Pipe Connection (as specified in Section C.2.11 of the SWDM). If the impervious area credited as mitigated is not sufficient, a fee in lieu will be paid, or the Native Growth Retention Credit will be implemented. Additionally, the project will amend soils and use perforated pipe connections for downspouts. 5. Conveyance System Analysis and Design Onsite Conveyance System: Runoff from the developed project site will be collected by the onsite conveyance system. The proposed stormwater drainage system is composed of catch basin structures with pipes. The proposed stormwater drainage system will be designed to convey the 25-year peak flow rate generated by the developed tributary basin as required by the SWDM. The system will contain the 100-year flow within the catch basins without any backwater issues. A conveyance and backwater analysis will be completed to verify the capacity of the critical pipes in the system with the final TIR. Outlet Conveyance System: The proposed detention Vault 1 will discharge pre-developed forested stormwater runoff to the existing roadside conveyance system along Weyerhaeuser Way S and will continue to North Lake for an estimated maximum 100-year flow of 0.725 cfs, which is less than the 100-year forested condition flow rate of 0.903 cfs for the same area. Since this flow is reduced, the existing conditions flow rate for the estimated 24-acre forested basin of 1.87 cfs will not be exceeded; therefore, the existing stormwater conveyance system downstream of Model A POC 1 is sufficient to convey the mitigated stormwater from the project site to North Lake. The proposed detention Ponds 2, 3, & 4 will match pre-developed conditions and discharge pre-developed forested stormwater runoff to Stream AC, which continues south to the Weyerhaeuser Pond for a combined 100 year discharged flow rate of (1.587 + 0.734 + 0.310) 2.631 cfs (Model B, POC 2-4). Furthermore, the existing forested and pasture areas that flow to Stream AC amount to approximately 14 acres and an associated 100-year flow rate of 1.581 cfs. In addition, Pond 5 will discharge 3.85 acre-feet of additional live storage to Weyerhaeuser Pond, to use the available additional live storage, which results in a 100-year discharged flow rate of 5.656 cfs (Model C, POC 5). The maximum stage height within Pond 5 over the top of the 24-inch diameter riser at that flow rate is 0.43 feet, refer to the chart in this section of the report for more information. The total stormwater runoff to this location is 9.868 cfs (2.631 + 1.581 + 5.656), which is less than the existing culverts preliminary calculated flow capacity of 12.84 cfs, using a Manning’s n of 0.013. Conveyance and backwater calculations will be provided with the final TIR. 6. Special Reports and Studies The original Critical Areas Report and Mitigation Plans by Wet. Consultants, Inc., dated April 9, 2020 have been included under separate cover. The Critical Areas Report Addendum and revised Mitigation Plans Critical by Wet.land, LLC., dated December 1, 2023 are also included under separate cover. The Geotechnical Engineering Report by GeoEngineers, dated January 10, 2020, is included under separate cover. 7. Other Permits Building and NPDES permits will be required for this project, together with permits for utility connections. These will be applied for and provided at a later date. 8. ESC Analysis and Design The Erosion and Sedimentation Control calculations will be provided with the final TIR. 9. Bond Quantities, Facility Summaries, and Declaration of Covenant The Bond Quantities worksheet will be provided with the final TIR. The Facilities Summaries and Declaration of Covenant will be evaluated with final design to determine if applicable. 10. Operations and Maintenance The Operations and Maintenance manual will be provided with the final TIR. Appendix A Developed Basin Map S 3 3 6 T H S T WEYERH A E U S E R W A Y S . n SCALE: 1" = 100'C O N S U L T I N G E N G I N E E R SL L CFederal Way, WA 9800333400 8th Ave S, Suite 205FEDERAL WAY CAMPUS LLCWOODRIDGE BUSINESS PARKEN-43 1 1 INTE R S T A T E 5 BUILDING "1" ±606,000 SF FF=VARIES 442.37-448.87 BUILDING "2" ±240,900 SF FF=VARIES 420.00-424.75 FUTURE BUILDING "3" ±125,700 SF FF=VARIES 422.00-424.5 EXISTING WTC BUILDING FF=437.00 LEGEND Appendix B Hydrology Model Output Model A POC 1 is associated with Vault 1’s mitigated outflow. POC 2 is associated with Basin 1’s water quality treatment flow. Model B POC 1 is associated with Pond 2, 3, 4, & 5’s mitigated outflow (pre- Pond 5 reduction). POC 2 is associated with Pond 2’s mitigated outflow and water quality treatment flow. POC 3 is associated with Pond 3’s mitigated outflow and water quality treatment flow. POC 4 is associated with Pond 4’s mitigated outflow and water quality treatment flow. POC 5 is associated with Pond 5’s mitigated outflow. POC 6 is associated with Basin 5’s water quality treatment flow. Model C POC 5 is associated with Pond 5’s reduced size outflow. POC 6 is associated with Basin 5’s water quality treatment flow (same as Model B). WWHM2012 PROJECT REPORT BP Model A 1/13/2023 2:38:20 PM Page 2 General Model Information Project Name:BP Model A Site Name:Business Park Site Address:Model A - Vault 1 City: Report Date:1/13/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year BP Model A 1/13/2023 2:38:20 PM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 11.16 Pervious Total 11.16 Impervious Land Use acre Impervious Total 0 Basin Total 11.16 Element Flows To: Surface Interflow Groundwater BP Model A 1/13/2023 2:38:20 PM Page 4 PreDev - Basin 1 - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.52 Pervious Total 0.52 Impervious Land Use acre Impervious Total 0 Basin Total 0.52 Element Flows To: Surface Interflow Groundwater BP Model A 1/13/2023 2:38:20 PM Page 5 Mitigated Land Use Dev - Basin 1 - Roof Only Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 4.89 Impervious Total 4.89 Basin Total 4.89 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 BP Model A 1/13/2023 2:38:20 PM Page 6 Dev - Basin 1 - No Roof Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.81 Pervious Total 0.81 Impervious Land Use acre ROADS FLAT 5.46 Impervious Total 5.46 Basin Total 6.27 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 BP Model A 1/13/2023 2:38:20 PM Page 7 Dev - Basin 1 - Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.52 Pervious Total 0.52 Impervious Land Use acre Impervious Total 0 Basin Total 0.52 Element Flows To: Surface Interflow Groundwater BP Model A 1/13/2023 2:38:20 PM Page 9 Mitigated Routing Vault 1 Width:360 ft. Length:100 ft. Depth:9 ft. Discharge Structure Riser Height:6.5 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.021 ft. Notch Height:2.300 ft. Orifice 1 Diameter:1.83 in.Elevation:0 ft. Orifice 2 Diameter:1.469 in.Elevation:3.3 ft. Orifice 3 Diameter:1.625 in.Elevation:3.6 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.826 0.000 0.000 0.000 0.1000 0.826 0.082 0.028 0.000 0.2000 0.826 0.165 0.040 0.000 0.3000 0.826 0.247 0.049 0.000 0.4000 0.826 0.330 0.057 0.000 0.5000 0.826 0.413 0.064 0.000 0.6000 0.826 0.495 0.070 0.000 0.7000 0.826 0.578 0.076 0.000 0.8000 0.826 0.661 0.081 0.000 0.9000 0.826 0.743 0.086 0.000 1.0000 0.826 0.826 0.090 0.000 1.1000 0.826 0.909 0.095 0.000 1.2000 0.826 0.991 0.099 0.000 1.3000 0.826 1.074 0.103 0.000 1.4000 0.826 1.157 0.107 0.000 1.5000 0.826 1.239 0.111 0.000 1.6000 0.826 1.322 0.115 0.000 1.7000 0.826 1.405 0.118 0.000 1.8000 0.826 1.487 0.121 0.000 1.9000 0.826 1.570 0.125 0.000 2.0000 0.826 1.652 0.128 0.000 2.1000 0.826 1.735 0.131 0.000 2.2000 0.826 1.818 0.134 0.000 2.3000 0.826 1.900 0.137 0.000 2.4000 0.826 1.983 0.140 0.000 2.5000 0.826 2.066 0.143 0.000 2.6000 0.826 2.148 0.146 0.000 2.7000 0.826 2.231 0.149 0.000 2.8000 0.826 2.314 0.152 0.000 2.9000 0.826 2.396 0.154 0.000 3.0000 0.826 2.479 0.157 0.000 3.1000 0.826 2.562 0.160 0.000 3.2000 0.826 2.644 0.162 0.000 3.3000 0.826 2.727 0.165 0.000 3.4000 0.826 2.809 0.186 0.000 BP Model A 1/13/2023 2:38:20 PM Page 10 3.5000 0.826 2.892 0.196 0.000 3.6000 0.826 2.975 0.204 0.000 3.7000 0.826 3.057 0.234 0.000 3.8000 0.826 3.140 0.250 0.000 3.9000 0.826 3.223 0.264 0.000 4.0000 0.826 3.305 0.276 0.000 4.1000 0.826 3.388 0.287 0.000 4.2000 0.826 3.471 0.297 0.000 4.3000 0.826 3.553 0.309 0.000 4.4000 0.826 3.636 0.322 0.000 4.5000 0.826 3.719 0.335 0.000 4.6000 0.826 3.801 0.349 0.000 4.7000 0.826 3.884 0.363 0.000 4.8000 0.826 3.966 0.377 0.000 4.9000 0.826 4.049 0.391 0.000 5.0000 0.826 4.132 0.406 0.000 5.1000 0.826 4.214 0.420 0.000 5.2000 0.826 4.297 0.434 0.000 5.3000 0.826 4.380 0.449 0.000 5.4000 0.826 4.462 0.465 0.000 5.5000 0.826 4.545 0.480 0.000 5.6000 0.826 4.628 0.497 0.000 5.7000 0.826 4.710 0.545 0.000 5.8000 0.826 4.793 0.565 0.000 5.9000 0.826 4.876 0.586 0.000 6.0000 0.826 4.958 0.606 0.000 6.1000 0.826 5.041 0.627 0.000 6.2000 0.826 5.124 0.648 0.000 6.3000 0.826 5.206 0.669 0.000 6.4000 0.826 5.289 0.691 0.000 6.5000 0.826 5.371 0.713 0.000 6.6000 0.826 5.454 1.221 0.000 6.7000 0.826 5.537 2.129 0.000 6.8000 0.826 5.619 3.231 0.000 6.9000 0.826 5.702 4.367 0.000 7.0000 0.826 5.785 5.379 0.000 7.1000 0.826 5.867 6.146 0.000 7.2000 0.826 5.950 6.643 0.000 7.3000 0.826 6.033 7.094 0.000 7.4000 0.826 6.115 7.483 0.000 7.5000 0.826 6.198 7.852 0.000 7.6000 0.826 6.281 8.203 0.000 7.7000 0.826 6.363 8.538 0.000 7.8000 0.826 6.446 8.860 0.000 7.9000 0.826 6.528 9.169 0.000 8.0000 0.826 6.611 9.468 0.000 8.1000 0.826 6.694 9.758 0.000 8.2000 0.826 6.776 10.03 0.000 8.3000 0.826 6.859 10.31 0.000 8.4000 0.826 6.942 10.57 0.000 8.5000 0.826 7.024 10.83 0.000 8.6000 0.826 7.107 11.08 0.000 8.7000 0.826 7.190 11.33 0.000 8.8000 0.826 7.272 11.57 0.000 8.9000 0.826 7.355 11.80 0.000 9.0000 0.826 7.438 12.03 0.000 9.1000 0.826 7.520 12.26 0.000 9.2000 0.000 0.000 12.48 0.000 BP Model A 1/13/2023 2:38:20 PM Page 12 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:11.68 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.33 Total Impervious Area:10.35 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.343402 5 year 0.539326 10 year 0.65036 25 year 0.76799 50 year 0.84078 100 year 0.902691 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.224115 5 year 0.329876 10 year 0.410666 25 year 0.52562 50 year 0.621022 100 year 0.725155 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.337 0.192 1950 0.421 0.223 1951 0.756 0.499 1952 0.238 0.139 1953 0.193 0.207 1954 0.296 0.170 1955 0.472 0.172 1956 0.376 0.330 1957 0.303 0.173 1958 0.341 0.182 BP Model A 1/13/2023 2:38:50 PM Page 13 1959 0.293 0.164 1960 0.511 0.399 1961 0.288 0.269 1962 0.179 0.139 1963 0.246 0.176 1964 0.324 0.263 1965 0.232 0.296 1966 0.223 0.169 1967 0.467 0.237 1968 0.291 0.170 1969 0.285 0.163 1970 0.235 0.181 1971 0.251 0.196 1972 0.563 0.406 1973 0.256 0.292 1974 0.278 0.172 1975 0.376 0.185 1976 0.272 0.174 1977 0.032 0.145 1978 0.239 0.210 1979 0.144 0.131 1980 0.534 0.425 1981 0.213 0.170 1982 0.410 0.391 1983 0.368 0.174 1984 0.227 0.147 1985 0.135 0.149 1986 0.595 0.249 1987 0.526 0.381 1988 0.208 0.161 1989 0.136 0.149 1990 1.101 0.419 1991 0.663 0.420 1992 0.256 0.200 1993 0.266 0.145 1994 0.089 0.127 1995 0.382 0.281 1996 0.805 0.471 1997 0.673 0.483 1998 0.152 0.163 1999 0.631 0.421 2000 0.266 0.217 2001 0.048 0.117 2002 0.291 0.283 2003 0.371 0.170 2004 0.481 0.516 2005 0.345 0.167 2006 0.407 0.325 2007 0.817 0.655 2008 1.054 0.450 2009 0.518 0.312 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.1008 0.6549 2 1.0540 0.5157 3 0.8171 0.4995 BP Model A 1/13/2023 2:38:50 PM Page 14 4 0.8046 0.4832 5 0.7562 0.4712 6 0.6726 0.4503 7 0.6628 0.4247 8 0.6308 0.4208 9 0.5952 0.4200 10 0.5631 0.4190 11 0.5337 0.4062 12 0.5265 0.3993 13 0.5175 0.3907 14 0.5113 0.3806 15 0.4806 0.3303 16 0.4719 0.3248 17 0.4669 0.3123 18 0.4206 0.2956 19 0.4102 0.2916 20 0.4066 0.2828 21 0.3818 0.2810 22 0.3762 0.2691 23 0.3755 0.2626 24 0.3712 0.2488 25 0.3678 0.2370 26 0.3448 0.2230 27 0.3414 0.2171 28 0.3373 0.2103 29 0.3244 0.2067 30 0.3030 0.2000 31 0.2960 0.1959 32 0.2929 0.1923 33 0.2913 0.1848 34 0.2910 0.1821 35 0.2885 0.1813 36 0.2850 0.1756 37 0.2776 0.1740 38 0.2720 0.1737 39 0.2663 0.1735 40 0.2655 0.1722 41 0.2558 0.1720 42 0.2556 0.1703 43 0.2513 0.1700 44 0.2464 0.1699 45 0.2386 0.1697 46 0.2383 0.1690 47 0.2350 0.1674 48 0.2322 0.1644 49 0.2270 0.1629 50 0.2233 0.1626 51 0.2133 0.1611 52 0.2078 0.1493 53 0.1927 0.1492 54 0.1795 0.1466 55 0.1522 0.1454 56 0.1442 0.1451 57 0.1356 0.1387 58 0.1347 0.1386 59 0.0895 0.1314 60 0.0476 0.1267 61 0.0324 0.1169 BP Model A 1/13/2023 2:38:50 PM Page 16 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.1717 17725 17370 97 Pass 0.1785 16241 14155 87 Pass 0.1852 14998 12844 85 Pass 0.1920 13995 12044 86 Pass 0.1987 12919 10895 84 Pass 0.2055 11879 9698 81 Pass 0.2123 10928 8598 78 Pass 0.2190 10119 8040 79 Pass 0.2258 9460 7694 81 Pass 0.2325 8782 7362 83 Pass 0.2393 8171 7041 86 Pass 0.2460 7593 6729 88 Pass 0.2528 7118 6378 89 Pass 0.2596 6611 5963 90 Pass 0.2663 6164 5559 90 Pass 0.2731 5781 5133 88 Pass 0.2798 5473 4723 86 Pass 0.2866 5135 4273 83 Pass 0.2934 4819 3936 81 Pass 0.3001 4528 3643 80 Pass 0.3069 4284 3420 79 Pass 0.3136 4040 3127 77 Pass 0.3204 3799 2866 75 Pass 0.3271 3551 2586 72 Pass 0.3339 3364 2432 72 Pass 0.3407 3153 2254 71 Pass 0.3474 2960 2073 70 Pass 0.3542 2789 1909 68 Pass 0.3609 2620 1776 67 Pass 0.3677 2460 1588 64 Pass 0.3745 2314 1445 62 Pass 0.3812 2162 1301 60 Pass 0.3880 2049 1195 58 Pass 0.3947 1911 1071 56 Pass 0.4015 1795 927 51 Pass 0.4082 1694 822 48 Pass 0.4150 1583 724 45 Pass 0.4218 1492 630 42 Pass 0.4285 1387 535 38 Pass 0.4353 1293 473 36 Pass 0.4420 1218 403 33 Pass 0.4488 1160 364 31 Pass 0.4556 1099 337 30 Pass 0.4623 1049 306 29 Pass 0.4691 997 272 27 Pass 0.4758 938 245 26 Pass 0.4826 888 222 25 Pass 0.4893 840 196 23 Pass 0.4961 789 174 22 Pass 0.5029 746 151 20 Pass 0.5096 718 133 18 Pass 0.5164 673 116 17 Pass 0.5231 632 114 18 Pass BP Model A 1/13/2023 2:38:50 PM Page 17 0.5299 600 112 18 Pass 0.5367 569 111 19 Pass 0.5434 540 109 20 Pass 0.5502 497 108 21 Pass 0.5569 476 106 22 Pass 0.5637 440 104 23 Pass 0.5704 402 102 25 Pass 0.5772 369 89 24 Pass 0.5840 351 81 23 Pass 0.5907 326 67 20 Pass 0.5975 297 61 20 Pass 0.6042 273 55 20 Pass 0.6110 259 50 19 Pass 0.6178 237 45 18 Pass 0.6245 218 41 18 Pass 0.6313 198 36 18 Pass 0.6380 180 32 17 Pass 0.6448 158 28 17 Pass 0.6515 146 10 6 Pass 0.6583 130 0 0 Pass 0.6651 119 0 0 Pass 0.6718 110 0 0 Pass 0.6786 97 0 0 Pass 0.6853 91 0 0 Pass 0.6921 82 0 0 Pass 0.6989 78 0 0 Pass 0.7056 69 0 0 Pass 0.7124 61 0 0 Pass 0.7191 54 0 0 Pass 0.7259 48 0 0 Pass 0.7326 42 0 0 Pass 0.7394 38 0 0 Pass 0.7462 33 0 0 Pass 0.7529 28 0 0 Pass 0.7597 23 0 0 Pass 0.7664 21 0 0 Pass 0.7732 20 0 0 Pass 0.7800 19 0 0 Pass 0.7867 17 0 0 Pass 0.7935 14 0 0 Pass 0.8002 12 0 0 Pass 0.8070 9 0 0 Pass 0.8137 4 0 0 Pass 0.8205 3 0 0 Pass 0.8273 3 0 0 Pass 0.8340 3 0 0 Pass 0.8408 3 0 0 Pass BP Model A 1/13/2023 2:38:50 PM Page 18 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:1.292 acre-feet On-line facility target flow:1.6716 cfs. Adjusted for 15 min:1.6716 cfs. Off-line facility target flow:0.9453 cfs. Adjusted for 15 min:0.9453 cfs. BP Model A 1/13/2023 2:38:50 PM Page 19 LID Report BP Model A 1/13/2023 2:39:13 PM Page 22 Appendix Predeveloped Schematic BP Model A 1/13/2023 2:39:13 PM Page 23 Mitigated Schematic BP Model A 1/13/2023 2:39:14 PM Page 36 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT BP Model B 12/7/2023 10:14:17 AM Page 2 General Model Information WWHM2012 Project Name:BP Model B Site Name:Business Park Site Address:Model B - Ponds 2 through 5 City: Report Date:12/7/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Low Flow Threshold for POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Low Flow Threshold for POC6:50 Percent of the 2 Year High Flow Threshold for POC6:50 Year BP Model B 12/7/2023 10:14:17 AM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Basin 5 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.92 Pervious Total 12.92 Impervious Land Use acre Impervious Total 0 Basin Total 12.92 BP Model B 12/7/2023 10:14:17 AM Page 4 Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.93 Pervious Total 0.93 Impervious Land Use acre Impervious Total 0 Basin Total 0.93 BP Model B 12/7/2023 10:14:17 AM Page 5 PreDev - Basin 5 - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.75 Pervious Total 0.75 Impervious Land Use acre Impervious Total 0 Basin Total 0.75 BP Model B 12/7/2023 10:14:17 AM Page 6 Pond 4 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.76 Pervious Total 0.76 Impervious Land Use acre Impervious Total 0 Basin Total 0.76 BP Model B 12/7/2023 10:14:17 AM Page 7 PreDev - Basin 4 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 5.51 Pervious Total 5.51 Impervious Land Use acre Impervious Total 0 Basin Total 5.51 BP Model B 12/7/2023 10:14:17 AM Page 8 PreDev - Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 14.46 Pervious Total 14.46 Impervious Land Use acre Impervious Total 0 Basin Total 14.46 BP Model B 12/7/2023 10:14:17 AM Page 9 Pond 3 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.64 Pervious Total 1.64 Impervious Land Use acre Impervious Total 0 Basin Total 1.64 BP Model B 12/7/2023 10:14:17 AM Page 10 PreDev - Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 20.38 Pervious Total 20.38 Impervious Land Use acre Impervious Total 0 Basin Total 20.38 BP Model B 12/7/2023 10:14:17 AM Page 11 Pond 2 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 2.09 Pervious Total 2.09 Impervious Land Use acre Impervious Total 0 Basin Total 2.09 BP Model B 12/7/2023 10:14:17 AM Page 12 PreDev - Basin 2 - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.36 Pervious Total 0.36 Impervious Land Use acre Impervious Total 0 Basin Total 0.36 BP Model B 12/7/2023 10:14:17 AM Page 13 PreDev - Basin 5 - WQ Node Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 5.82 Impervious Total 5.82 Basin Total 7.39 BP Model B 12/7/2023 10:14:17 AM Page 14 Mitigated Land Use Dev - Basin 5 - Roof Only Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 5.53 Impervious Total 5.53 Basin Total 5.53 BP Model B 12/7/2023 10:14:17 AM Page 15 Dev - Basin 5 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.24 Pervious Total 0.24 Impervious Land Use acre ROADS FLAT 0.51 Impervious Total 0.51 Basin Total 0.75 BP Model B 12/7/2023 10:14:17 AM Page 16 Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.93 Pervious Total 0.93 Impervious Land Use acre Impervious Total 0 Basin Total 0.93 BP Model B 12/7/2023 10:14:17 AM Page 17 Pond 4 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.76 Pervious Total 0.76 Impervious Land Use acre Impervious Total 0 Basin Total 0.76 BP Model B 12/7/2023 10:14:17 AM Page 18 Dev - Basin 4 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.37 Pervious Total 0.37 Impervious Land Use acre ROADS FLAT 3.89 ROOF TOPS FLAT 1.25 Impervious Total 5.14 Basin Total 5.51 BP Model B 12/7/2023 10:14:17 AM Page 19 Dev - Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.42 Pervious Total 1.42 Impervious Land Use acre ROADS FLAT 5.91 ROOF TOPS FLAT 7.13 Impervious Total 13.04 Basin Total 14.46 BP Model B 12/7/2023 10:14:17 AM Page 20 Pond 3 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.64 Pervious Total 1.64 Impervious Land Use acre Impervious Total 0 Basin Total 1.64 BP Model B 12/7/2023 10:14:17 AM Page 21 Dev - Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.11 Pervious Total 1.11 Impervious Land Use acre ROADS FLAT 10.25 ROOF TOPS FLAT 9.02 Impervious Total 19.27 Basin Total 20.38 BP Model B 12/7/2023 10:14:17 AM Page 22 Pond 2 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.09 Pervious Total 2.09 Impervious Land Use acre Impervious Total 0 Basin Total 2.09 BP Model B 12/7/2023 10:14:17 AM Page 23 Dev - Basin 2 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.03 Pervious Total 0.03 Impervious Land Use acre ROADS FLAT 0.33 Impervious Total 0.33 Basin Total 0.36 BP Model B 12/7/2023 10:14:17 AM Page 24 Dev - Basin 5 - PGIS Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 5.82 Impervious Total 5.82 Basin Total 7.39 BP Model B 12/7/2023 10:14:17 AM Page 25 Routing Elements Predeveloped Routing Business Park POC Bottom Length:10.00 ft. Bottom Width:10.00 ft. Manning's n:0.0001 Channel bottom slope 1:1 To 1 Channel Left side slope 0:0 To 1 Channel right side slope 2:0 To 1 Discharge Structure Riser Height:0 ft. Riser Diameter:0 in. Element Flows To: Outlet 1 Outlet 2 Channel Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.002 0.000 0.000 0.000 0.1000 0.002 0.000 3168.0.000 0.2000 0.002 0.000 9928.0.000 0.3000 0.002 0.000 19268 0.000 0.4000 0.002 0.001 30737 0.000 0.5000 0.002 0.001 44042 0.000 0.6000 0.002 0.001 58969 0.000 0.7000 0.002 0.001 75349 0.000 0.8000 0.002 0.002 93045 0.000 0.9000 0.002 0.002 11194 0.000 1.0000 0.002 0.002 13194 0.000 1.1000 0.002 0.002 15296 0.000 1.2000 0.002 0.003 17493 0.000 1.3000 0.002 0.003 19777 0.000 1.4000 0.002 0.003 22144 0.000 1.5000 0.003 0.004 24587 0.000 1.6000 0.003 0.004 27102 0.000 1.7000 0.003 0.004 29684 0.000 1.8000 0.003 0.004 32330 0.000 1.9000 0.003 0.005 35036 0.000 2.0000 0.003 0.005 37799 0.000 2.1000 0.003 0.005 40615 0.000 2.2000 0.003 0.006 43482 0.000 2.3000 0.003 0.006 46397 0.000 2.4000 0.003 0.006 49358 0.000 2.5000 0.003 0.007 52363 0.000 2.6000 0.003 0.007 55408 0.000 2.7000 0.003 0.007 58494 0.000 2.8000 0.003 0.008 61616 0.000 2.9000 0.003 0.008 64775 0.000 3.0000 0.003 0.009 67968 0.000 3.1000 0.003 0.009 71194 0.000 3.2000 0.003 0.009 74451 0.000 3.3000 0.003 0.010 77738 0.000 3.4000 0.003 0.010 81054 0.000 3.5000 0.003 0.010 84398 0.000 BP Model B 12/7/2023 10:14:17 AM Page 26 3.6000 0.003 0.011 87768 0.000 3.7000 0.004 0.011 91163 0.000 3.8000 0.004 0.012 94583 0.000 3.9000 0.004 0.012 98027 0.000 4.0000 0.004 0.012 10149 0.000 4.1000 0.004 0.013 10498 0.000 4.2000 0.004 0.013 10849 0.000 4.3000 0.004 0.014 11201 0.000 4.4000 0.004 0.014 11556 0.000 4.5000 0.004 0.015 11913 0.000 4.6000 0.004 0.015 12271 0.000 4.7000 0.004 0.015 12632 0.000 4.8000 0.004 0.016 12994 0.000 4.9000 0.004 0.016 13357 0.000 5.0000 0.004 0.017 13723 0.000 5.1000 0.004 0.017 14089 0.000 5.2000 0.004 0.018 14457 0.000 5.3000 0.004 0.018 14827 0.000 5.4000 0.004 0.019 15198 0.000 5.5000 0.004 0.019 15570 0.000 5.6000 0.004 0.020 15944 0.000 5.7000 0.004 0.020 16319 0.000 5.8000 0.005 0.021 16695 0.000 5.9000 0.005 0.021 17072 0.000 6.0000 0.005 0.022 17451 0.000 6.1000 0.005 0.022 17830 0.000 6.2000 0.005 0.023 18211 0.000 6.3000 0.005 0.023 18592 0.000 6.4000 0.005 0.024 18975 0.000 6.5000 0.005 0.024 19359 0.000 6.6000 0.005 0.025 19743 0.000 6.7000 0.005 0.025 20129 0.000 6.8000 0.005 0.026 20516 0.000 6.9000 0.005 0.026 20903 0.000 7.0000 0.005 0.027 21291 0.000 7.1000 0.005 0.027 21680 0.000 7.2000 0.005 0.028 22070 0.000 7.3000 0.005 0.029 22461 0.000 7.4000 0.005 0.029 22852 0.000 7.5000 0.005 0.030 23244 0.000 7.6000 0.005 0.030 23637 0.000 7.7000 0.005 0.031 24031 0.000 7.8000 0.005 0.031 24425 0.000 7.9000 0.005 0.032 24820 0.000 8.0000 0.006 0.033 25216 0.000 8.1000 0.006 0.033 25612 0.000 8.2000 0.006 0.034 26009 0.000 8.3000 0.006 0.034 26407 0.000 8.4000 0.006 0.035 26805 0.000 8.5000 0.006 0.036 27204 0.000 8.6000 0.006 0.036 27603 0.000 8.7000 0.006 0.037 28003 0.000 8.8000 0.006 0.038 28404 0.000 8.9000 0.006 0.038 28805 0.000 9.0000 0.006 0.039 29206 0.000 9.1000 0.006 0.039 29608 0.000 BP Model B 12/7/2023 10:14:17 AM Page 27 Mitigated Routing Pond 2 - 2:1 SS Bottom Length:370.00 ft. Bottom Width:147.00 ft. Depth:9 ft. Volume at riser head:9.3101 acre-feet. Side slope 1:2 To 1 Side slope 2:2 To 1 Side slope 3:2 To 1 Side slope 4:2 To 1 Discharge Structure Riser Height:6.5 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.062 ft. Notch Height:1.800 ft. Orifice 1 Diameter:2.520 in.Elevation:0 ft. Orifice 2 Diameter:2.250 in.Elevation:3.6 ft. Orifice 3 Diameter:2.500 in.Elevation:4 ft. Element Flows To: Outlet 1 Outlet 2 Business Park POC Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 1.248 0.000 0.000 0.000 0.1000 1.253 0.125 0.054 0.000 0.2000 1.258 0.250 0.077 0.000 0.3000 1.262 0.376 0.094 0.000 0.4000 1.267 0.503 0.109 0.000 0.5000 1.272 0.630 0.121 0.000 0.6000 1.277 0.757 0.133 0.000 0.7000 1.282 0.885 0.144 0.000 0.8000 1.286 1.014 0.154 0.000 0.9000 1.291 1.143 0.163 0.000 1.0000 1.296 1.272 0.172 0.000 1.1000 1.301 1.402 0.180 0.000 1.2000 1.306 1.532 0.188 0.000 1.3000 1.311 1.663 0.196 0.000 1.4000 1.315 1.794 0.203 0.000 1.5000 1.320 1.926 0.211 0.000 1.6000 1.325 2.059 0.218 0.000 1.7000 1.330 2.191 0.224 0.000 1.8000 1.335 2.325 0.231 0.000 1.9000 1.340 2.458 0.237 0.000 2.0000 1.345 2.593 0.243 0.000 2.1000 1.349 2.727 0.249 0.000 2.2000 1.354 2.863 0.255 0.000 2.3000 1.359 2.998 0.261 0.000 2.4000 1.364 3.135 0.267 0.000 2.5000 1.369 3.271 0.272 0.000 2.6000 1.374 3.409 0.277 0.000 2.7000 1.379 3.546 0.283 0.000 2.8000 1.384 3.684 0.288 0.000 2.9000 1.389 3.823 0.293 0.000 BP Model B 12/7/2023 10:14:17 AM Page 28 3.0000 1.394 3.962 0.298 0.000 3.1000 1.399 4.102 0.303 0.000 3.2000 1.404 4.242 0.308 0.000 3.3000 1.409 4.383 0.313 0.000 3.4000 1.414 4.524 0.317 0.000 3.5000 1.419 4.666 0.322 0.000 3.6000 1.424 4.808 0.327 0.000 3.7000 1.429 4.951 0.374 0.000 3.8000 1.434 5.094 0.397 0.000 3.9000 1.439 5.237 0.415 0.000 4.0000 1.444 5.382 0.431 0.000 4.1000 1.449 5.526 0.499 0.000 4.2000 1.454 5.672 0.535 0.000 4.3000 1.459 5.817 0.565 0.000 4.4000 1.464 5.963 0.591 0.000 4.5000 1.469 6.110 0.615 0.000 4.6000 1.474 6.257 0.638 0.000 4.7000 1.479 6.405 0.659 0.000 4.8000 1.485 6.553 0.686 0.000 4.9000 1.490 6.702 0.716 0.000 5.0000 1.495 6.851 0.749 0.000 5.1000 1.500 7.001 0.783 0.000 5.2000 1.505 7.151 0.818 0.000 5.3000 1.510 7.302 0.853 0.000 5.4000 1.515 7.454 0.889 0.000 5.5000 1.520 7.605 0.925 0.000 5.6000 1.526 7.758 0.961 0.000 5.7000 1.531 7.911 0.996 0.000 5.8000 1.536 8.064 1.036 0.000 5.9000 1.541 8.218 1.077 0.000 6.0000 1.546 8.372 1.119 0.000 6.1000 1.551 8.527 1.162 0.000 6.2000 1.557 8.683 1.302 0.000 6.3000 1.562 8.839 1.356 0.000 6.4000 1.567 8.995 1.411 0.000 6.5000 1.572 9.152 1.468 0.000 6.6000 1.578 9.310 1.982 0.000 6.7000 1.583 9.468 2.897 0.000 6.8000 1.588 9.626 4.006 0.000 6.9000 1.593 9.785 5.149 0.000 7.0000 1.598 9.945 6.168 0.000 7.1000 1.604 10.10 6.942 0.000 7.2000 1.609 10.26 7.445 0.000 7.3000 1.614 10.42 7.903 0.000 7.4000 1.620 10.58 8.298 0.000 7.5000 1.625 10.75 8.673 0.000 7.6000 1.630 10.91 9.030 0.000 7.7000 1.636 11.07 9.372 0.000 7.8000 1.641 11.24 9.700 0.000 7.9000 1.646 11.40 10.01 0.000 8.0000 1.651 11.57 10.32 0.000 8.1000 1.657 11.73 10.61 0.000 8.2000 1.662 11.90 10.90 0.000 8.3000 1.668 12.06 11.18 0.000 8.4000 1.673 12.23 11.45 0.000 8.5000 1.678 12.40 11.71 0.000 8.6000 1.684 12.57 11.97 0.000 8.7000 1.689 12.74 12.22 0.000 BP Model B 12/7/2023 10:14:17 AM Page 29 8.8000 1.694 12.91 12.47 0.000 8.9000 1.700 13.07 12.71 0.000 9.0000 1.705 13.25 12.94 0.000 9.1000 1.711 13.42 13.17 0.000 BP Model B 12/7/2023 10:14:17 AM Page 30 Pond 3 - 2:1 SS Bottom Length:270.00 ft. Bottom Width:122.00 ft. Depth:9 ft. Volume at riser head:6.8404 acre-feet. Side slope 1:2 To 1 Side slope 2:2 To 1 Side slope 3:2 To 1 Side slope 4:2 To 1 Discharge Structure Riser Height:7.5 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.042 ft. Notch Height:2.100 ft. Orifice 1 Diameter:2.060 in.Elevation:0 ft. Orifice 2 Diameter:1.190 in.Elevation:4.2 ft. Orifice 3 Diameter:1.940 in.Elevation:6.9 ft. Element Flows To: Outlet 1 Outlet 2 Business Park POC Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.756 0.000 0.000 0.000 0.1000 0.759 0.075 0.036 0.000 0.2000 0.763 0.152 0.051 0.000 0.3000 0.767 0.228 0.063 0.000 0.4000 0.770 0.305 0.072 0.000 0.5000 0.774 0.382 0.081 0.000 0.6000 0.777 0.460 0.089 0.000 0.7000 0.781 0.538 0.096 0.000 0.8000 0.785 0.616 0.103 0.000 0.9000 0.788 0.695 0.109 0.000 1.0000 0.792 0.774 0.115 0.000 1.1000 0.796 0.853 0.120 0.000 1.2000 0.799 0.933 0.126 0.000 1.3000 0.803 1.013 0.131 0.000 1.4000 0.807 1.094 0.136 0.000 1.5000 0.811 1.175 0.141 0.000 1.6000 0.814 1.256 0.145 0.000 1.7000 0.818 1.338 0.150 0.000 1.8000 0.822 1.420 0.154 0.000 1.9000 0.825 1.502 0.158 0.000 2.0000 0.829 1.585 0.162 0.000 2.1000 0.833 1.668 0.166 0.000 2.2000 0.837 1.752 0.170 0.000 2.3000 0.840 1.836 0.174 0.000 2.4000 0.844 1.920 0.178 0.000 2.5000 0.848 2.004 0.182 0.000 2.6000 0.852 2.089 0.185 0.000 2.7000 0.856 2.175 0.189 0.000 2.8000 0.859 2.261 0.192 0.000 2.9000 0.863 2.347 0.196 0.000 3.0000 0.867 2.433 0.199 0.000 3.1000 0.871 2.520 0.202 0.000 BP Model B 12/7/2023 10:14:17 AM Page 31 3.2000 0.875 2.608 0.206 0.000 3.3000 0.879 2.695 0.209 0.000 3.4000 0.882 2.783 0.212 0.000 3.5000 0.886 2.872 0.215 0.000 3.6000 0.890 2.961 0.218 0.000 3.7000 0.894 3.050 0.221 0.000 3.8000 0.898 3.140 0.224 0.000 3.9000 0.902 3.230 0.227 0.000 4.0000 0.906 3.320 0.230 0.000 4.1000 0.910 3.411 0.233 0.000 4.2000 0.913 3.502 0.236 0.000 4.3000 0.917 3.594 0.250 0.000 4.4000 0.921 3.686 0.258 0.000 4.5000 0.925 3.778 0.265 0.000 4.6000 0.929 3.871 0.271 0.000 4.7000 0.933 3.964 0.276 0.000 4.8000 0.937 4.058 0.282 0.000 4.9000 0.941 4.151 0.287 0.000 5.0000 0.945 4.246 0.291 0.000 5.1000 0.949 4.341 0.296 0.000 5.2000 0.953 4.436 0.301 0.000 5.3000 0.957 4.531 0.305 0.000 5.4000 0.961 4.627 0.309 0.000 5.5000 0.965 4.723 0.318 0.000 5.6000 0.969 4.820 0.329 0.000 5.7000 0.973 4.917 0.343 0.000 5.8000 0.977 5.015 0.358 0.000 5.9000 0.981 5.113 0.373 0.000 6.0000 0.985 5.211 0.390 0.000 6.1000 0.989 5.310 0.407 0.000 6.2000 0.993 5.409 0.424 0.000 6.3000 0.997 5.509 0.441 0.000 6.4000 1.001 5.609 0.459 0.000 6.5000 1.005 5.709 0.479 0.000 6.6000 1.009 5.810 0.501 0.000 6.7000 1.013 5.911 0.523 0.000 6.8000 1.018 6.012 0.545 0.000 6.9000 1.022 6.114 0.634 0.000 7.0000 1.026 6.217 0.697 0.000 7.1000 1.030 6.320 0.742 0.000 7.2000 1.034 6.423 0.784 0.000 7.3000 1.038 6.527 0.826 0.000 7.4000 1.042 6.631 0.868 0.000 7.5000 1.046 6.735 0.909 0.000 7.6000 1.051 6.840 1.421 0.000 7.7000 1.055 6.945 2.332 0.000 7.8000 1.059 7.051 3.437 0.000 7.9000 1.063 7.157 4.577 0.000 8.0000 1.067 7.264 5.592 0.000 8.1000 1.071 7.371 6.362 0.000 8.2000 1.076 7.478 6.860 0.000 8.3000 1.080 7.586 7.314 0.000 8.4000 1.084 7.694 7.705 0.000 8.5000 1.088 7.803 8.076 0.000 8.6000 1.092 7.912 8.429 0.000 8.7000 1.097 8.021 8.766 0.000 8.8000 1.101 8.131 9.090 0.000 8.9000 1.105 8.242 9.401 0.000 BP Model B 12/7/2023 10:14:17 AM Page 32 9.0000 1.109 8.352 9.702 0.000 9.1000 1.114 8.464 9.993 0.000 BP Model B 12/7/2023 10:14:17 AM Page 33 Pond 4 - 2.7:1 SS Bottom Length:160.00 ft. Bottom Width:91.00 ft. Depth:9 ft. Volume at riser head:2.6685 acre-feet. Side slope 1:2.7 To 1 Side slope 2:2.7 To 1 Side slope 3:2.7 To 1 Side slope 4:2.7 To 1 Discharge Structure Riser Height:6 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.026 ft. Notch Height:1.200 ft. Orifice 1 Diameter:1.270 in.Elevation:0 ft. Orifice 2 Diameter:1.070 in.Elevation:4.3 ft. Orifice 3 Diameter:1.125 in.Elevation:5.1 ft. Element Flows To: Outlet 1 Outlet 2 Business Park POC Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.334 0.000 0.000 0.000 0.1000 0.337 0.033 0.013 0.000 0.2000 0.340 0.067 0.019 0.000 0.3000 0.343 0.101 0.024 0.000 0.4000 0.346 0.136 0.027 0.000 0.5000 0.350 0.171 0.030 0.000 0.6000 0.353 0.206 0.033 0.000 0.7000 0.356 0.241 0.036 0.000 0.8000 0.359 0.277 0.039 0.000 0.9000 0.362 0.313 0.041 0.000 1.0000 0.366 0.350 0.043 0.000 1.1000 0.369 0.386 0.045 0.000 1.2000 0.372 0.423 0.047 0.000 1.3000 0.375 0.461 0.049 0.000 1.4000 0.379 0.499 0.051 0.000 1.5000 0.382 0.537 0.053 0.000 1.6000 0.385 0.575 0.055 0.000 1.7000 0.389 0.614 0.057 0.000 1.8000 0.392 0.653 0.058 0.000 1.9000 0.395 0.692 0.060 0.000 2.0000 0.399 0.732 0.061 0.000 2.1000 0.402 0.772 0.063 0.000 2.2000 0.405 0.813 0.064 0.000 2.3000 0.409 0.853 0.066 0.000 2.4000 0.412 0.894 0.067 0.000 2.5000 0.416 0.936 0.069 0.000 2.6000 0.419 0.978 0.070 0.000 2.7000 0.423 1.020 0.071 0.000 2.8000 0.426 1.062 0.073 0.000 2.9000 0.430 1.105 0.074 0.000 3.0000 0.433 1.148 0.075 0.000 3.1000 0.437 1.192 0.077 0.000 BP Model B 12/7/2023 10:14:17 AM Page 34 3.2000 0.440 1.236 0.078 0.000 3.3000 0.444 1.280 0.079 0.000 3.4000 0.447 1.325 0.080 0.000 3.5000 0.451 1.370 0.081 0.000 3.6000 0.454 1.415 0.083 0.000 3.7000 0.458 1.461 0.084 0.000 3.8000 0.462 1.507 0.085 0.000 3.9000 0.465 1.553 0.086 0.000 4.0000 0.469 1.600 0.087 0.000 4.1000 0.473 1.647 0.088 0.000 4.2000 0.476 1.694 0.089 0.000 4.3000 0.480 1.742 0.090 0.000 4.4000 0.484 1.790 0.101 0.000 4.5000 0.487 1.839 0.106 0.000 4.6000 0.491 1.888 0.110 0.000 4.7000 0.495 1.937 0.114 0.000 4.8000 0.499 1.987 0.117 0.000 4.9000 0.502 2.037 0.123 0.000 5.0000 0.506 2.088 0.131 0.000 5.1000 0.510 2.138 0.140 0.000 5.2000 0.514 2.190 0.160 0.000 5.3000 0.518 2.241 0.174 0.000 5.4000 0.521 2.293 0.188 0.000 5.5000 0.525 2.346 0.202 0.000 5.6000 0.529 2.398 0.215 0.000 5.7000 0.533 2.452 0.228 0.000 5.8000 0.537 2.505 0.241 0.000 5.9000 0.541 2.559 0.256 0.000 6.0000 0.545 2.613 0.271 0.000 6.1000 0.549 2.668 0.777 0.000 6.2000 0.552 2.723 1.683 0.000 6.3000 0.556 2.779 2.783 0.000 6.4000 0.560 2.835 3.918 0.000 6.5000 0.564 2.891 4.928 0.000 6.6000 0.568 2.947 5.693 0.000 6.7000 0.572 3.005 6.188 0.000 6.8000 0.576 3.062 6.637 0.000 6.9000 0.580 3.120 7.025 0.000 7.0000 0.584 3.178 7.391 0.000 7.1000 0.588 3.237 7.740 0.000 7.2000 0.593 3.296 8.074 0.000 7.3000 0.597 3.355 8.394 0.000 7.4000 0.601 3.415 8.702 0.000 7.5000 0.605 3.476 8.999 0.000 7.6000 0.609 3.536 9.286 0.000 7.7000 0.613 3.598 9.565 0.000 7.8000 0.617 3.659 9.835 0.000 7.9000 0.621 3.721 10.09 0.000 8.0000 0.626 3.784 10.35 0.000 8.1000 0.630 3.846 10.60 0.000 8.2000 0.634 3.910 10.84 0.000 8.3000 0.638 3.973 11.08 0.000 8.4000 0.642 4.037 11.32 0.000 8.5000 0.647 4.102 11.55 0.000 8.6000 0.651 4.167 11.77 0.000 8.7000 0.655 4.232 11.99 0.000 8.8000 0.659 4.298 12.21 0.000 8.9000 0.664 4.364 12.42 0.000 BP Model B 12/7/2023 10:14:17 AM Page 35 9.0000 0.668 4.431 12.63 0.000 9.1000 0.672 4.498 12.83 0.000 BP Model B 12/7/2023 10:14:17 AM Page 36 Pond 5 - 4:1 SS Bottom Length:205.00 ft. Bottom Width:302.00 ft. Depth:4.5 ft. Volume at riser head:5.5657 acre-feet. Side slope 1:4 To 1 Side slope 2:4 To 1 Side slope 3:4 To 1 Side slope 4:4 To 1 Discharge Structure Riser Height:3.5 ft. Riser Diameter:18 in. Notch Type:Rectangular Notch Width:0.104 ft. Notch Height:1.200 ft. Orifice 1 Diameter:2.170 in.Elevation:0 ft. Orifice 2 Diameter:1.875 in.Elevation:2.1 ft. Orifice 3 Diameter:2.441 in.Elevation:2.2 ft. Element Flows To: Outlet 1 Outlet 2 Business Park POC Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 1.421 0.000 0.000 0.000 0.0500 1.425 0.071 0.028 0.000 0.1000 1.430 0.142 0.040 0.000 0.1500 1.435 0.214 0.049 0.000 0.2000 1.439 0.286 0.057 0.000 0.2500 1.444 0.358 0.063 0.000 0.3000 1.449 0.430 0.070 0.000 0.3500 1.454 0.503 0.075 0.000 0.4000 1.458 0.576 0.080 0.000 0.4500 1.463 0.649 0.085 0.000 0.5000 1.468 0.722 0.090 0.000 0.5500 1.472 0.795 0.094 0.000 0.6000 1.477 0.869 0.099 0.000 0.6500 1.482 0.943 0.103 0.000 0.7000 1.487 1.017 0.106 0.000 0.7500 1.491 1.092 0.110 0.000 0.8000 1.496 1.167 0.114 0.000 0.8500 1.501 1.242 0.117 0.000 0.9000 1.506 1.317 0.121 0.000 0.9500 1.511 1.392 0.124 0.000 1.0000 1.515 1.468 0.127 0.000 1.0500 1.520 1.544 0.130 0.000 1.1000 1.525 1.620 0.134 0.000 1.1500 1.530 1.696 0.137 0.000 1.2000 1.535 1.773 0.140 0.000 1.2500 1.539 1.850 0.142 0.000 1.3000 1.544 1.927 0.145 0.000 1.3500 1.549 2.004 0.148 0.000 1.4000 1.554 2.082 0.151 0.000 1.4500 1.559 2.160 0.153 0.000 1.5000 1.564 2.238 0.156 0.000 1.5500 1.569 2.316 0.159 0.000 BP Model B 12/7/2023 10:14:17 AM Page 37 1.6000 1.574 2.395 0.161 0.000 1.6500 1.578 2.474 0.164 0.000 1.7000 1.583 2.553 0.166 0.000 1.7500 1.588 2.632 0.169 0.000 1.8000 1.593 2.712 0.171 0.000 1.8500 1.598 2.791 0.173 0.000 1.9000 1.603 2.871 0.176 0.000 1.9500 1.608 2.952 0.178 0.000 2.0000 1.613 3.032 0.180 0.000 2.0500 1.618 3.113 0.183 0.000 2.1000 1.623 3.194 0.185 0.000 2.1500 1.628 3.275 0.208 0.000 2.2000 1.633 3.357 0.219 0.000 2.2500 1.638 3.439 0.264 0.000 2.3000 1.643 3.521 0.287 0.000 2.3500 1.648 3.603 0.310 0.000 2.4000 1.653 3.686 0.333 0.000 2.4500 1.658 3.768 0.356 0.000 2.5000 1.663 3.851 0.380 0.000 2.5500 1.668 3.935 0.404 0.000 2.6000 1.673 4.018 0.429 0.000 2.6500 1.678 4.102 0.453 0.000 2.7000 1.683 4.186 0.478 0.000 2.7500 1.688 4.270 0.503 0.000 2.8000 1.693 4.355 0.529 0.000 2.8500 1.698 4.440 0.554 0.000 2.9000 1.703 4.525 0.579 0.000 2.9500 1.708 4.610 0.605 0.000 3.0000 1.713 4.696 0.630 0.000 3.0500 1.718 4.781 0.656 0.000 3.1000 1.724 4.867 0.681 0.000 3.1500 1.729 4.954 0.707 0.000 3.2000 1.734 5.040 0.732 0.000 3.2500 1.739 5.127 0.758 0.000 3.3000 1.744 5.214 0.783 0.000 3.3500 1.749 5.302 0.812 0.000 3.4000 1.754 5.389 0.841 0.000 3.4500 1.760 5.477 0.870 0.000 3.5000 1.765 5.565 0.900 0.000 3.5500 1.770 5.654 1.085 0.000 3.6000 1.775 5.742 1.417 0.000 3.6500 1.780 5.831 1.840 0.000 3.7000 1.785 5.920 2.333 0.000 3.7500 1.791 6.010 2.873 0.000 3.8000 1.796 6.099 3.443 0.000 3.8500 1.801 6.189 4.021 0.000 3.9000 1.806 6.280 4.587 0.000 3.9500 1.812 6.370 5.122 0.000 4.0000 1.817 6.461 5.607 0.000 4.0500 1.822 6.552 6.029 0.000 4.1000 1.827 6.643 6.382 0.000 4.1500 1.833 6.735 6.663 0.000 4.2000 1.838 6.826 6.885 0.000 4.2500 1.843 6.918 7.070 0.000 4.3000 1.848 7.011 7.343 0.000 4.3500 1.854 7.103 7.544 0.000 4.4000 1.859 7.196 7.739 0.000 4.4500 1.864 7.289 7.929 0.000 BP Model B 12/7/2023 10:14:17 AM Page 38 4.5000 1.870 7.383 8.115 0.000 4.5500 1.875 7.476 8.295 0.000 BP Model B 12/7/2023 10:14:17 AM Page 39 Business Park POC Bottom Length:10.00 ft. Bottom Width:10.00 ft. Manning's n:0.0001 Channel bottom slope 1:1 To 1 Channel Left side slope 0:0 To 1 Channel right side slope 2:0 To 1 Discharge Structure Riser Height:0 ft. Riser Diameter:0 in. Element Flows To: Outlet 1 Outlet 2 Channel Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.002 0.000 0.000 0.000 0.1000 0.002 0.000 3168.0.000 0.2000 0.002 0.000 9928.0.000 0.3000 0.002 0.000 19268 0.000 0.4000 0.002 0.001 30737 0.000 0.5000 0.002 0.001 44042 0.000 0.6000 0.002 0.001 58969 0.000 0.7000 0.002 0.001 75349 0.000 0.8000 0.002 0.002 93045 0.000 0.9000 0.002 0.002 11194 0.000 1.0000 0.002 0.002 13194 0.000 1.1000 0.002 0.002 15296 0.000 1.2000 0.002 0.003 17493 0.000 1.3000 0.002 0.003 19777 0.000 1.4000 0.002 0.003 22144 0.000 1.5000 0.003 0.004 24587 0.000 1.6000 0.003 0.004 27102 0.000 1.7000 0.003 0.004 29684 0.000 1.8000 0.003 0.004 32330 0.000 1.9000 0.003 0.005 35036 0.000 2.0000 0.003 0.005 37799 0.000 2.1000 0.003 0.005 40615 0.000 2.2000 0.003 0.006 43482 0.000 2.3000 0.003 0.006 46397 0.000 2.4000 0.003 0.006 49358 0.000 2.5000 0.003 0.007 52363 0.000 2.6000 0.003 0.007 55408 0.000 2.7000 0.003 0.007 58494 0.000 2.8000 0.003 0.008 61616 0.000 2.9000 0.003 0.008 64775 0.000 3.0000 0.003 0.009 67968 0.000 3.1000 0.003 0.009 71194 0.000 3.2000 0.003 0.009 74451 0.000 3.3000 0.003 0.010 77738 0.000 3.4000 0.003 0.010 81054 0.000 3.5000 0.003 0.010 84398 0.000 3.6000 0.003 0.011 87768 0.000 3.7000 0.004 0.011 91163 0.000 3.8000 0.004 0.012 94583 0.000 3.9000 0.004 0.012 98027 0.000 BP Model B 12/7/2023 10:14:17 AM Page 40 4.0000 0.004 0.012 10149 0.000 4.1000 0.004 0.013 10498 0.000 4.2000 0.004 0.013 10849 0.000 4.3000 0.004 0.014 11201 0.000 4.4000 0.004 0.014 11556 0.000 4.5000 0.004 0.015 11913 0.000 4.6000 0.004 0.015 12271 0.000 4.7000 0.004 0.015 12632 0.000 4.8000 0.004 0.016 12994 0.000 4.9000 0.004 0.016 13357 0.000 5.0000 0.004 0.017 13723 0.000 5.1000 0.004 0.017 14089 0.000 5.2000 0.004 0.018 14457 0.000 5.3000 0.004 0.018 14827 0.000 5.4000 0.004 0.019 15198 0.000 5.5000 0.004 0.019 15570 0.000 5.6000 0.004 0.020 15944 0.000 5.7000 0.004 0.020 16319 0.000 5.8000 0.005 0.021 16695 0.000 5.9000 0.005 0.021 17072 0.000 6.0000 0.005 0.022 17451 0.000 6.1000 0.005 0.022 17830 0.000 6.2000 0.005 0.023 18211 0.000 6.3000 0.005 0.023 18592 0.000 6.4000 0.005 0.024 18975 0.000 6.5000 0.005 0.024 19359 0.000 6.6000 0.005 0.025 19743 0.000 6.7000 0.005 0.025 20129 0.000 6.8000 0.005 0.026 20516 0.000 6.9000 0.005 0.026 20903 0.000 7.0000 0.005 0.027 21291 0.000 7.1000 0.005 0.027 21680 0.000 7.2000 0.005 0.028 22070 0.000 7.3000 0.005 0.029 22461 0.000 7.4000 0.005 0.029 22852 0.000 7.5000 0.005 0.030 23244 0.000 7.6000 0.005 0.030 23637 0.000 7.7000 0.005 0.031 24031 0.000 7.8000 0.005 0.031 24425 0.000 7.9000 0.005 0.032 24820 0.000 8.0000 0.006 0.033 25216 0.000 8.1000 0.006 0.033 25612 0.000 8.2000 0.006 0.034 26009 0.000 8.3000 0.006 0.034 26407 0.000 8.4000 0.006 0.035 26805 0.000 8.5000 0.006 0.036 27204 0.000 8.6000 0.006 0.036 27603 0.000 8.7000 0.006 0.037 28003 0.000 8.8000 0.006 0.038 28404 0.000 8.9000 0.006 0.038 28805 0.000 9.0000 0.006 0.039 29206 0.000 9.1000 0.006 0.039 29608 0.000 BP Model B 12/7/2023 10:14:17 AM Page 41 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:59.8 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:10.16 Total Impervious Area:49.64 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 1.75817 5 year 2.761275 10 year 3.329752 25 year 3.932004 50 year 4.30468 100 year 4.621657 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.174002 5 year 1.691342 10 year 2.096716 25 year 2.686683 50 year 3.186841 100 year 3.742652 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 1.727 0.974 1950 2.153 1.177 1951 3.872 2.614 1952 1.220 0.777 1953 0.987 1.058 1954 1.515 0.864 1955 2.416 0.955 1956 1.923 1.644 1957 1.552 0.988 1958 1.748 0.963 BP Model B 12/7/2023 10:14:54 AM Page 42 1959 1.499 0.909 1960 2.618 1.982 1961 1.477 1.434 1962 0.919 0.742 1963 1.262 0.953 1964 1.661 1.279 1965 1.189 1.475 1966 1.143 0.947 1967 2.391 1.128 1968 1.491 0.929 1969 1.459 0.908 1970 1.203 0.967 1971 1.287 1.045 1972 2.883 2.097 1973 1.310 1.443 1974 1.421 0.940 1975 1.926 1.022 1976 1.392 0.884 1977 0.166 0.890 1978 1.222 1.123 1979 0.738 0.744 1980 2.732 2.241 1981 1.092 0.922 1982 2.100 1.965 1983 1.883 0.910 1984 1.162 0.818 1985 0.690 0.849 1986 3.047 1.214 1987 2.696 1.837 1988 1.064 0.915 1989 0.694 0.835 1990 5.636 2.033 1991 3.393 2.083 1992 1.309 1.062 1993 1.363 0.750 1994 0.458 0.722 1995 1.955 1.355 1996 4.120 2.462 1997 3.444 2.794 1998 0.779 0.913 1999 3.229 2.117 2000 1.359 1.087 2001 0.244 0.867 2002 1.490 1.316 2003 1.900 0.907 2004 2.461 2.575 2005 1.765 0.921 2006 2.082 1.635 2007 4.183 3.859 2008 5.396 2.248 2009 2.650 1.506 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 5.6359 3.8585 2 5.3965 2.7940 3 4.1834 2.6143 BP Model B 12/7/2023 10:14:54 AM Page 43 4 4.1196 2.5754 5 3.8716 2.4616 6 3.4438 2.2479 7 3.3935 2.2405 8 3.2294 2.1170 9 3.0474 2.0974 10 2.8832 2.0831 11 2.7324 2.0330 12 2.6955 1.9823 13 2.6497 1.9651 14 2.6179 1.8370 15 2.4606 1.6436 16 2.4162 1.6352 17 2.3907 1.5055 18 2.1535 1.4753 19 2.1003 1.4431 20 2.0817 1.4341 21 1.9547 1.3553 22 1.9260 1.3161 23 1.9227 1.2794 24 1.9004 1.2139 25 1.8830 1.1765 26 1.7652 1.1280 27 1.7480 1.1234 28 1.7271 1.0866 29 1.6607 1.0622 30 1.5516 1.0577 31 1.5153 1.0453 32 1.4994 1.0225 33 1.4913 0.9885 34 1.4896 0.9742 35 1.4769 0.9667 36 1.4590 0.9632 37 1.4215 0.9550 38 1.3924 0.9528 39 1.3632 0.9475 40 1.3594 0.9400 41 1.3097 0.9288 42 1.3088 0.9218 43 1.2867 0.9209 44 1.2616 0.9149 45 1.2217 0.9130 46 1.2200 0.9103 47 1.2031 0.9091 48 1.1891 0.9076 49 1.1624 0.9073 50 1.1432 0.8896 51 1.0920 0.8836 52 1.0637 0.8671 53 0.9867 0.8643 54 0.9190 0.8493 55 0.7790 0.8350 56 0.7382 0.8178 57 0.6940 0.7773 58 0.6898 0.7499 59 0.4581 0.7436 60 0.2438 0.7424 61 0.1657 0.7224 BP Model B 12/7/2023 10:14:54 AM Page 45 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.8791 17554 16288 92 Pass 0.9137 16189 14245 87 Pass 0.9483 14974 12718 84 Pass 0.9829 13873 11248 81 Pass 1.0175 12820 9995 77 Pass 1.0521 11809 8955 75 Pass 1.0867 10908 8158 74 Pass 1.1213 10121 7563 74 Pass 1.1559 9398 7150 76 Pass 1.1905 8737 6716 76 Pass 1.2251 8145 6248 76 Pass 1.2597 7604 5779 75 Pass 1.2943 7063 5270 74 Pass 1.3289 6594 4847 73 Pass 1.3635 6151 4406 71 Pass 1.3981 5777 4025 69 Pass 1.4327 5437 3707 68 Pass 1.4673 5101 3414 66 Pass 1.5019 4815 3213 66 Pass 1.5365 4528 2960 65 Pass 1.5711 4252 2708 63 Pass 1.6057 4019 2494 62 Pass 1.6403 3784 2323 61 Pass 1.6749 3553 2171 61 Pass 1.7095 3339 2031 60 Pass 1.7441 3138 1861 59 Pass 1.7787 2954 1737 58 Pass 1.8133 2787 1603 57 Pass 1.8479 2601 1483 57 Pass 1.8825 2449 1359 55 Pass 1.9171 2304 1257 54 Pass 1.9517 2162 1134 52 Pass 1.9863 2026 1002 49 Pass 2.0210 1901 908 47 Pass 2.0556 1790 820 45 Pass 2.0902 1687 729 43 Pass 2.1248 1590 653 41 Pass 2.1594 1483 600 40 Pass 2.1940 1382 533 38 Pass 2.2286 1292 460 35 Pass 2.2632 1218 426 34 Pass 2.2978 1155 389 33 Pass 2.3324 1098 352 32 Pass 2.3670 1049 325 30 Pass 2.4016 997 296 29 Pass 2.4362 930 267 28 Pass 2.4708 884 234 26 Pass 2.5054 837 207 24 Pass 2.5400 789 188 23 Pass 2.5746 743 168 22 Pass 2.6092 713 151 21 Pass 2.6438 669 145 21 Pass 2.6784 631 139 22 Pass BP Model B 12/7/2023 10:14:54 AM Page 46 2.7130 596 134 22 Pass 2.7476 566 122 21 Pass 2.7822 539 116 21 Pass 2.8168 497 112 22 Pass 2.8514 473 109 23 Pass 2.8860 435 106 24 Pass 2.9206 400 104 26 Pass 2.9552 366 94 25 Pass 2.9898 348 82 23 Pass 3.0244 323 80 24 Pass 3.0590 296 70 23 Pass 3.0936 272 66 24 Pass 3.1282 256 64 25 Pass 3.1628 235 61 25 Pass 3.1974 217 58 26 Pass 3.2320 195 53 27 Pass 3.2666 180 50 27 Pass 3.3012 158 45 28 Pass 3.3358 145 42 28 Pass 3.3704 129 39 30 Pass 3.4050 119 37 31 Pass 3.4396 109 35 32 Pass 3.4742 97 32 32 Pass 3.5088 91 28 30 Pass 3.5434 82 23 28 Pass 3.5780 76 14 18 Pass 3.6126 69 13 18 Pass 3.6472 61 12 19 Pass 3.6818 54 9 16 Pass 3.7164 48 8 16 Pass 3.7510 41 7 17 Pass 3.7857 38 6 15 Pass 3.8203 33 4 12 Pass 3.8549 27 2 7 Pass 3.8895 22 0 0 Pass 3.9241 21 0 0 Pass 3.9587 20 0 0 Pass 3.9933 19 0 0 Pass 4.0279 17 0 0 Pass 4.0625 14 0 0 Pass 4.0971 12 0 0 Pass 4.1317 9 0 0 Pass 4.1663 4 0 0 Pass 4.2009 3 0 0 Pass 4.2355 3 0 0 Pass 4.2701 3 0 0 Pass 4.3047 3 0 0 Pass BP Model B 12/7/2023 10:14:54 AM Page 47 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. BP Model B 12/7/2023 10:14:54 AM Page 48 LID Report BP Model B 12/7/2023 10:17:24 AM Page 49 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:22.83 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:3.23 Total Impervious Area:19.6 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.671221 5 year 1.054179 10 year 1.271208 25 year 1.501131 50 year 1.643408 100 year 1.764421 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.47959 5 year 0.704907 10 year 0.880519 25 year 1.134797 50 year 1.349267 100 year 1.586526 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.659 0.374 1950 0.822 0.469 1951 1.478 1.081 1952 0.466 0.305 1953 0.377 0.423 1954 0.578 0.340 1955 0.922 0.372 1956 0.734 0.681 1957 0.592 0.386 1958 0.667 0.406 1959 0.572 0.355 BP Model B 12/7/2023 10:18:01 AM Page 50 1960 0.999 0.867 1961 0.564 0.592 1962 0.351 0.293 1963 0.482 0.374 1964 0.634 0.535 1965 0.454 0.636 1966 0.436 0.370 1967 0.913 0.460 1968 0.569 0.366 1969 0.557 0.354 1970 0.459 0.397 1971 0.491 0.407 1972 1.101 0.852 1973 0.500 0.624 1974 0.543 0.367 1975 0.735 0.398 1976 0.532 0.345 1977 0.063 0.354 1978 0.466 0.464 1979 0.282 0.292 1980 1.043 0.900 1981 0.417 0.360 1982 0.802 0.835 1983 0.719 0.358 1984 0.444 0.321 1985 0.263 0.338 1986 1.163 0.536 1987 1.029 0.810 1988 0.406 0.362 1989 0.265 0.331 1990 2.152 0.869 1991 1.296 0.874 1992 0.500 0.437 1993 0.520 0.297 1994 0.175 0.285 1995 0.746 0.585 1996 1.573 1.024 1997 1.315 1.053 1998 0.297 0.359 1999 1.233 0.887 2000 0.519 0.466 2001 0.093 0.344 2002 0.569 0.598 2003 0.726 0.350 2004 0.939 1.114 2005 0.674 0.361 2006 0.795 0.683 2007 1.597 1.613 2008 2.060 0.975 2009 1.012 0.661 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 2.1516 1.6133 2 2.0602 1.1138 3 1.5971 1.0815 4 1.5728 1.0526 BP Model B 12/7/2023 10:18:01 AM Page 51 5 1.4781 1.0237 6 1.3147 0.9753 7 1.2955 0.9004 8 1.2329 0.8874 9 1.1634 0.8740 10 1.1007 0.8687 11 1.0432 0.8675 12 1.0291 0.8519 13 1.0116 0.8350 14 0.9994 0.8101 15 0.9394 0.6825 16 0.9224 0.6806 17 0.9127 0.6607 18 0.8221 0.6357 19 0.8018 0.6238 20 0.7947 0.5977 21 0.7463 0.5916 22 0.7353 0.5845 23 0.7340 0.5357 24 0.7255 0.5350 25 0.7189 0.4688 26 0.6739 0.4662 27 0.6674 0.4641 28 0.6593 0.4599 29 0.6340 0.4374 30 0.5923 0.4228 31 0.5785 0.4074 32 0.5724 0.4064 33 0.5693 0.3982 34 0.5687 0.3966 35 0.5638 0.3860 36 0.5570 0.3743 37 0.5427 0.3738 38 0.5316 0.3718 39 0.5204 0.3704 40 0.5190 0.3674 41 0.5000 0.3658 42 0.4997 0.3615 43 0.4912 0.3611 44 0.4816 0.3604 45 0.4664 0.3586 46 0.4658 0.3584 47 0.4593 0.3546 48 0.4540 0.3544 49 0.4438 0.3543 50 0.4364 0.3505 51 0.4169 0.3450 52 0.4061 0.3438 53 0.3767 0.3401 54 0.3508 0.3375 55 0.2974 0.3310 56 0.2818 0.3215 57 0.2650 0.3054 58 0.2633 0.2968 59 0.1749 0.2926 60 0.0931 0.2921 61 0.0633 0.2855 BP Model B 12/7/2023 10:18:01 AM Page 53 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.3356 17624 17197 97 Pass 0.3488 16232 15280 94 Pass 0.3620 14966 14099 94 Pass 0.3752 13864 13310 96 Pass 0.3885 12840 12140 94 Pass 0.4017 11864 10904 91 Pass 0.4149 10945 9704 88 Pass 0.4281 10121 8449 83 Pass 0.4413 9396 7835 83 Pass 0.4545 8754 7529 86 Pass 0.4677 8175 7266 88 Pass 0.4809 7634 7022 91 Pass 0.4941 7063 6770 95 Pass 0.5073 6594 6492 98 Pass 0.5206 6162 6098 98 Pass 0.5338 5792 5739 99 Pass 0.5470 5454 5345 98 Pass 0.5602 5103 4934 96 Pass 0.5734 4815 4545 94 Pass 0.5866 4539 4226 93 Pass 0.5998 4267 3933 92 Pass 0.6130 4017 3640 90 Pass 0.6262 3784 3412 90 Pass 0.6394 3553 3168 89 Pass 0.6527 3345 2928 87 Pass 0.6659 3146 2629 83 Pass 0.6791 2952 2411 81 Pass 0.6923 2789 2265 81 Pass 0.7055 2603 2127 81 Pass 0.7187 2451 1960 79 Pass 0.7319 2314 1820 78 Pass 0.7451 2162 1671 77 Pass 0.7583 2028 1560 76 Pass 0.7715 1905 1456 76 Pass 0.7848 1793 1368 76 Pass 0.7980 1697 1249 73 Pass 0.8112 1588 1141 71 Pass 0.8244 1483 1059 71 Pass 0.8376 1385 977 70 Pass 0.8508 1295 878 67 Pass 0.8640 1217 766 62 Pass 0.8772 1155 686 59 Pass 0.8904 1098 618 56 Pass 0.9036 1049 549 52 Pass 0.9169 998 497 49 Pass 0.9301 930 443 47 Pass 0.9433 884 398 45 Pass 0.9565 839 362 43 Pass 0.9697 790 328 41 Pass 0.9829 744 301 40 Pass 0.9961 713 278 38 Pass 1.0093 670 257 38 Pass 1.0225 633 233 36 Pass BP Model B 12/7/2023 10:18:01 AM Page 54 1.0357 597 211 35 Pass 1.0490 569 194 34 Pass 1.0622 539 171 31 Pass 1.0754 497 156 31 Pass 1.0886 473 135 28 Pass 1.1018 437 126 28 Pass 1.1150 399 113 28 Pass 1.1282 366 111 30 Pass 1.1414 348 107 30 Pass 1.1546 324 104 32 Pass 1.1678 297 92 30 Pass 1.1811 272 84 30 Pass 1.1943 256 83 32 Pass 1.2075 235 79 33 Pass 1.2207 217 73 33 Pass 1.2339 198 70 35 Pass 1.2471 180 68 37 Pass 1.2603 158 66 41 Pass 1.2735 145 64 44 Pass 1.2867 130 63 48 Pass 1.2999 119 62 52 Pass 1.3132 109 61 55 Pass 1.3264 97 58 59 Pass 1.3396 91 54 59 Pass 1.3528 82 52 63 Pass 1.3660 76 48 63 Pass 1.3792 69 46 66 Pass 1.3924 61 42 68 Pass 1.4056 55 40 72 Pass 1.4188 48 38 79 Pass 1.4320 41 36 87 Pass 1.4453 38 33 86 Pass 1.4585 33 27 81 Pass 1.4717 27 20 74 Pass 1.4849 22 17 77 Pass 1.4981 21 16 76 Pass 1.5113 20 13 65 Pass 1.5245 19 12 63 Pass 1.5377 17 11 64 Pass 1.5509 14 10 71 Pass 1.5641 12 7 58 Pass 1.5774 9 6 66 Pass 1.5906 4 4 100 Pass 1.6038 3 2 66 Pass 1.6170 3 0 0 Pass 1.6302 3 0 0 Pass 1.6434 3 0 0 Pass BP Model B 12/7/2023 10:18:01 AM Page 55 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.6061 acre-feet On-line facility target flow:0.3073 cfs. Adjusted for 15 min:0.3073 cfs. Off-line facility target flow:0.2082 cfs. Adjusted for 15 min:0.2082 cfs. BP Model B 12/7/2023 10:18:01 AM Page 56 LID Report BP Model B 12/7/2023 10:18:01 AM Page 57 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:16.1 Total Impervious Area:0 Mitigated Landuse Totals for POC #3 Total Pervious Area:3.06 Total Impervious Area:13.04 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 0.473354 5 year 0.74342 10 year 0.896471 25 year 1.058616 50 year 1.158951 100 year 1.244291 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 0.260112 5 year 0.358164 10 year 0.433859 25 year 0.542666 50 year 0.633914 100 year 0.734461 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 0.465 0.206 1950 0.580 0.263 1951 1.042 0.514 1952 0.328 0.187 1953 0.266 0.252 1954 0.408 0.220 1955 0.651 0.215 1956 0.518 0.316 1957 0.418 0.220 1958 0.471 0.236 1959 0.404 0.209 BP Model B 12/7/2023 10:18:36 AM Page 58 1960 0.705 0.393 1961 0.398 0.283 1962 0.247 0.189 1963 0.340 0.232 1964 0.447 0.275 1965 0.320 0.300 1966 0.308 0.225 1967 0.644 0.263 1968 0.401 0.224 1969 0.393 0.220 1970 0.324 0.235 1971 0.346 0.233 1972 0.776 0.415 1973 0.353 0.303 1974 0.383 0.230 1975 0.519 0.211 1976 0.375 0.224 1977 0.045 0.196 1978 0.329 0.260 1979 0.199 0.176 1980 0.736 0.502 1981 0.294 0.228 1982 0.565 0.316 1983 0.507 0.228 1984 0.313 0.191 1985 0.186 0.202 1986 0.820 0.271 1987 0.726 0.344 1988 0.286 0.213 1989 0.187 0.200 1990 1.517 0.391 1991 0.914 0.380 1992 0.352 0.262 1993 0.367 0.190 1994 0.123 0.172 1995 0.526 0.282 1996 1.109 0.488 1997 0.927 0.757 1998 0.210 0.191 1999 0.869 0.442 2000 0.366 0.265 2001 0.066 0.164 2002 0.401 0.284 2003 0.512 0.220 2004 0.662 0.504 2005 0.475 0.221 2006 0.560 0.321 2007 1.126 0.835 2008 1.453 0.455 2009 0.713 0.294 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #3 Rank Predeveloped Mitigated 1 1.5174 0.8352 2 1.4529 0.7567 3 1.1263 0.5140 4 1.1091 0.5040 BP Model B 12/7/2023 10:18:36 AM Page 59 5 1.0424 0.5018 6 0.9272 0.4876 7 0.9136 0.4545 8 0.8695 0.4420 9 0.8205 0.4149 10 0.7762 0.3932 11 0.7356 0.3912 12 0.7257 0.3801 13 0.7134 0.3436 14 0.7048 0.3213 15 0.6625 0.3164 16 0.6505 0.3163 17 0.6436 0.3025 18 0.5798 0.3002 19 0.5655 0.2943 20 0.5605 0.2843 21 0.5263 0.2832 22 0.5185 0.2817 23 0.5176 0.2748 24 0.5116 0.2711 25 0.5070 0.2649 26 0.4753 0.2635 27 0.4706 0.2634 28 0.4650 0.2615 29 0.4471 0.2601 30 0.4177 0.2524 31 0.4080 0.2355 32 0.4037 0.2355 33 0.4015 0.2327 34 0.4011 0.2323 35 0.3976 0.2298 36 0.3928 0.2283 37 0.3827 0.2279 38 0.3749 0.2251 39 0.3670 0.2244 40 0.3660 0.2243 41 0.3526 0.2211 42 0.3524 0.2203 43 0.3464 0.2200 44 0.3397 0.2199 45 0.3289 0.2196 46 0.3285 0.2148 47 0.3239 0.2131 48 0.3201 0.2114 49 0.3129 0.2085 50 0.3078 0.2061 51 0.2940 0.2016 52 0.2864 0.1995 53 0.2657 0.1964 54 0.2474 0.1914 55 0.2097 0.1908 56 0.1988 0.1897 57 0.1868 0.1888 58 0.1857 0.1869 59 0.1233 0.1757 60 0.0656 0.1717 61 0.0446 0.1636 BP Model B 12/7/2023 10:18:36 AM Page 60 BP Model B 12/7/2023 10:18:36 AM Page 61 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2367 17676 16978 96 Pass 0.2460 16303 15785 96 Pass 0.2553 14998 14123 94 Pass 0.2646 13907 12138 87 Pass 0.2739 12910 10493 81 Pass 0.2833 11832 8504 71 Pass 0.2926 10943 6883 62 Pass 0.3019 10175 5364 52 Pass 0.3112 9396 4301 45 Pass 0.3205 8765 3734 42 Pass 0.3298 8198 3414 41 Pass 0.3392 7602 3170 41 Pass 0.3485 7084 2890 40 Pass 0.3578 6613 2605 39 Pass 0.3671 6149 2408 39 Pass 0.3764 5790 2207 38 Pass 0.3857 5456 2028 37 Pass 0.3950 5097 1818 35 Pass 0.4044 4815 1685 34 Pass 0.4137 4545 1535 33 Pass 0.4230 4276 1357 31 Pass 0.4323 4021 1179 29 Pass 0.4416 3801 995 26 Pass 0.4509 3563 812 22 Pass 0.4603 3341 673 20 Pass 0.4696 3146 579 18 Pass 0.4789 2964 514 17 Pass 0.4882 2789 433 15 Pass 0.4975 2603 376 14 Pass 0.5068 2458 279 11 Pass 0.5162 2308 249 10 Pass 0.5255 2165 236 10 Pass 0.5348 2038 224 10 Pass 0.5441 1899 212 11 Pass 0.5534 1791 206 11 Pass 0.5627 1698 200 11 Pass 0.5720 1585 190 11 Pass 0.5814 1484 185 12 Pass 0.5907 1387 180 12 Pass 0.6000 1300 175 13 Pass 0.6093 1222 170 13 Pass 0.6186 1159 161 13 Pass 0.6279 1102 158 14 Pass 0.6373 1049 155 14 Pass 0.6466 998 153 15 Pass 0.6559 933 149 15 Pass 0.6652 884 145 16 Pass 0.6745 841 141 16 Pass 0.6838 790 138 17 Pass 0.6932 743 136 18 Pass 0.7025 716 130 18 Pass 0.7118 673 126 18 Pass 0.7211 631 121 19 Pass BP Model B 12/7/2023 10:18:36 AM Page 62 0.7304 596 114 19 Pass 0.7397 569 98 17 Pass 0.7491 539 79 14 Pass 0.7584 497 59 11 Pass 0.7677 475 54 11 Pass 0.7770 440 49 11 Pass 0.7863 401 44 10 Pass 0.7956 370 39 10 Pass 0.8049 350 35 10 Pass 0.8143 323 31 9 Pass 0.8236 297 24 8 Pass 0.8329 275 6 2 Pass 0.8422 256 0 0 Pass 0.8515 235 0 0 Pass 0.8608 218 0 0 Pass 0.8702 196 0 0 Pass 0.8795 181 0 0 Pass 0.8888 158 0 0 Pass 0.8981 145 0 0 Pass 0.9074 130 0 0 Pass 0.9167 119 0 0 Pass 0.9261 109 0 0 Pass 0.9354 97 0 0 Pass 0.9447 91 0 0 Pass 0.9540 82 0 0 Pass 0.9633 76 0 0 Pass 0.9726 69 0 0 Pass 0.9819 62 0 0 Pass 0.9913 54 0 0 Pass 1.0006 48 0 0 Pass 1.0099 42 0 0 Pass 1.0192 38 0 0 Pass 1.0285 33 0 0 Pass 1.0378 27 0 0 Pass 1.0472 22 0 0 Pass 1.0565 21 0 0 Pass 1.0658 20 0 0 Pass 1.0751 19 0 0 Pass 1.0844 17 0 0 Pass 1.0937 14 0 0 Pass 1.1031 12 0 0 Pass 1.1124 9 0 0 Pass 1.1217 4 0 0 Pass 1.1310 3 0 0 Pass 1.1403 3 0 0 Pass 1.1496 3 0 0 Pass 1.1590 3 0 0 Pass BP Model B 12/7/2023 10:18:36 AM Page 63 Water Quality Water Quality BMP Flow and Volume for POC #3 On-line facility volume:0.4287 acre-feet On-line facility target flow:0.2165 cfs. Adjusted for 15 min:0.2165 cfs. Off-line facility target flow:0.1443 cfs. Adjusted for 15 min:0.1443 cfs. BP Model B 12/7/2023 10:18:36 AM Page 64 LID Report BP Model B 12/7/2023 10:18:36 AM Page 65 POC 4 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #4 Total Pervious Area:6.27 Total Impervious Area:0 Mitigated Landuse Totals for POC #4 Total Pervious Area:1.13 Total Impervious Area:5.14 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 0.184343 5 year 0.289518 10 year 0.349123 25 year 0.412268 50 year 0.451343 100 year 0.484578 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 0.09393 5 year 0.135671 10 year 0.169121 25 year 0.218728 50 year 0.261511 100 year 0.309729 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 0.181 0.075 1950 0.226 0.088 1951 0.406 0.222 1952 0.128 0.068 1953 0.103 0.090 1954 0.159 0.078 1955 0.253 0.077 1956 0.202 0.138 1957 0.163 0.078 1958 0.183 0.084 1959 0.157 0.076 BP Model B 12/7/2023 10:19:13 AM Page 66 1960 0.274 0.135 1961 0.155 0.091 1962 0.096 0.069 1963 0.132 0.084 1964 0.174 0.090 1965 0.125 0.108 1966 0.120 0.082 1967 0.251 0.088 1968 0.156 0.081 1969 0.153 0.080 1970 0.126 0.085 1971 0.135 0.083 1972 0.302 0.188 1973 0.137 0.113 1974 0.149 0.082 1975 0.202 0.075 1976 0.146 0.080 1977 0.017 0.070 1978 0.128 0.087 1979 0.077 0.063 1980 0.286 0.214 1981 0.115 0.082 1982 0.220 0.114 1983 0.197 0.082 1984 0.122 0.069 1985 0.072 0.072 1986 0.320 0.086 1987 0.283 0.119 1988 0.112 0.077 1989 0.073 0.071 1990 0.591 0.135 1991 0.356 0.161 1992 0.137 0.087 1993 0.143 0.068 1994 0.048 0.062 1995 0.205 0.091 1996 0.432 0.206 1997 0.361 0.260 1998 0.082 0.070 1999 0.339 0.185 2000 0.143 0.086 2001 0.026 0.058 2002 0.156 0.089 2003 0.199 0.079 2004 0.258 0.200 2005 0.185 0.078 2006 0.218 0.131 2007 0.439 0.417 2008 0.566 0.173 2009 0.278 0.097 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #4 Rank Predeveloped Mitigated 1 0.5909 0.4174 2 0.5658 0.2602 3 0.4386 0.2216 4 0.4319 0.2136 BP Model B 12/7/2023 10:19:13 AM Page 67 5 0.4059 0.2060 6 0.3611 0.2001 7 0.3558 0.1877 8 0.3386 0.1847 9 0.3195 0.1734 10 0.3023 0.1612 11 0.2865 0.1378 12 0.2826 0.1353 13 0.2778 0.1352 14 0.2745 0.1311 15 0.2580 0.1188 16 0.2533 0.1136 17 0.2507 0.1125 18 0.2258 0.1084 19 0.2202 0.0970 20 0.2183 0.0907 21 0.2050 0.0905 22 0.2019 0.0904 23 0.2016 0.0898 24 0.1993 0.0889 25 0.1974 0.0882 26 0.1851 0.0879 27 0.1833 0.0867 28 0.1811 0.0866 29 0.1741 0.0865 30 0.1627 0.0863 31 0.1589 0.0855 32 0.1572 0.0843 33 0.1564 0.0837 34 0.1562 0.0827 35 0.1549 0.0820 36 0.1530 0.0819 37 0.1490 0.0818 38 0.1460 0.0816 39 0.1429 0.0805 40 0.1425 0.0800 41 0.1373 0.0798 42 0.1372 0.0787 43 0.1349 0.0782 44 0.1323 0.0779 45 0.1281 0.0779 46 0.1279 0.0772 47 0.1261 0.0771 48 0.1247 0.0762 49 0.1219 0.0753 50 0.1199 0.0746 51 0.1145 0.0715 52 0.1115 0.0712 53 0.1035 0.0705 54 0.0964 0.0699 55 0.0817 0.0694 56 0.0774 0.0688 57 0.0728 0.0681 58 0.0723 0.0680 59 0.0480 0.0633 60 0.0256 0.0617 61 0.0174 0.0581 BP Model B 12/7/2023 10:19:13 AM Page 69 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0922 17627 8930 50 Pass 0.0958 16439 8556 52 Pass 0.0994 15098 8049 53 Pass 0.1031 13864 7328 52 Pass 0.1067 12998 6530 50 Pass 0.1103 11901 5546 46 Pass 0.1139 11124 4894 43 Pass 0.1176 10220 4119 40 Pass 0.1212 9417 3578 37 Pass 0.1248 8864 3230 36 Pass 0.1285 8222 2817 34 Pass 0.1321 7604 2400 31 Pass 0.1357 7150 2199 30 Pass 0.1393 6620 1991 30 Pass 0.1430 6256 1918 30 Pass 0.1466 5828 1853 31 Pass 0.1502 5450 1784 32 Pass 0.1538 5180 1704 32 Pass 0.1575 4840 1601 33 Pass 0.1611 4530 1499 33 Pass 0.1647 4306 1409 32 Pass 0.1684 4040 1264 31 Pass 0.1720 3850 1169 30 Pass 0.1756 3578 1035 28 Pass 0.1792 3349 915 27 Pass 0.1829 3178 827 26 Pass 0.1865 2973 720 24 Pass 0.1901 2791 631 22 Pass 0.1938 2635 567 21 Pass 0.1974 2460 515 20 Pass 0.2010 2304 431 18 Pass 0.2046 2177 401 18 Pass 0.2083 2037 345 16 Pass 0.2119 1932 310 16 Pass 0.2155 1802 269 14 Pass 0.2192 1694 251 14 Pass 0.2228 1613 226 14 Pass 0.2264 1492 216 14 Pass 0.2300 1381 199 14 Pass 0.2337 1304 181 13 Pass 0.2373 1225 161 13 Pass 0.2409 1175 154 13 Pass 0.2445 1104 145 13 Pass 0.2482 1049 135 12 Pass 0.2518 1006 127 12 Pass 0.2554 938 116 12 Pass 0.2591 884 96 10 Pass 0.2627 846 51 6 Pass 0.2663 790 40 5 Pass 0.2699 749 34 4 Pass 0.2736 719 30 4 Pass 0.2772 672 29 4 Pass 0.2808 640 28 4 Pass BP Model B 12/7/2023 10:19:13 AM Page 70 0.2845 600 28 4 Pass 0.2881 567 26 4 Pass 0.2917 542 25 4 Pass 0.2953 500 24 4 Pass 0.2990 478 24 5 Pass 0.3026 440 24 5 Pass 0.3062 402 24 5 Pass 0.3099 378 23 6 Pass 0.3135 350 22 6 Pass 0.3171 323 21 6 Pass 0.3207 301 20 6 Pass 0.3244 275 19 6 Pass 0.3280 261 19 7 Pass 0.3316 239 18 7 Pass 0.3352 218 16 7 Pass 0.3389 203 13 6 Pass 0.3425 182 11 6 Pass 0.3461 158 11 6 Pass 0.3498 146 11 7 Pass 0.3534 131 11 8 Pass 0.3570 119 9 7 Pass 0.3606 110 9 8 Pass 0.3643 97 9 9 Pass 0.3679 93 9 9 Pass 0.3715 84 8 9 Pass 0.3752 76 8 10 Pass 0.3788 69 8 11 Pass 0.3824 62 8 12 Pass 0.3860 54 7 12 Pass 0.3897 48 6 12 Pass 0.3933 41 6 14 Pass 0.3969 38 6 15 Pass 0.4006 33 6 18 Pass 0.4042 27 5 18 Pass 0.4078 24 5 20 Pass 0.4114 21 4 19 Pass 0.4151 20 2 10 Pass 0.4187 19 0 0 Pass 0.4223 17 0 0 Pass 0.4259 14 0 0 Pass 0.4296 12 0 0 Pass 0.4332 9 0 0 Pass 0.4368 4 0 0 Pass 0.4405 3 0 0 Pass 0.4441 3 0 0 Pass 0.4477 3 0 0 Pass 0.4513 3 0 0 Pass BP Model B 12/7/2023 10:19:13 AM Page 71 Water Quality Water Quality BMP Flow and Volume for POC #4 On-line facility volume:0.1557 acre-feet On-line facility target flow:0.0786 cfs. Adjusted for 15 min:0.0786 cfs. Off-line facility target flow:0.053 cfs. Adjusted for 15 min:0.053 cfs. BP Model B 12/7/2023 10:19:13 AM Page 72 LID Report BP Model B 12/7/2023 10:19:13 AM Page 73 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:14.6 Total Impervious Area:0 Mitigated Landuse Totals for POC #5 Total Pervious Area:2.74 Total Impervious Area:11.86 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.429252 5 year 0.674157 10 year 0.812949 25 year 0.959987 50 year 1.050975 100 year 1.128364 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 0.39108 5 year 0.550536 10 year 0.67076 25 year 0.840237 50 year 0.979846 100 year 1.131422 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.422 0.402 1950 0.526 0.400 1951 0.945 0.838 1952 0.298 0.252 1953 0.241 0.305 1954 0.370 0.303 1955 0.590 0.337 1956 0.469 0.520 1957 0.379 0.361 1958 0.427 0.288 1959 0.366 0.285 BP Model B 12/7/2023 10:19:49 AM Page 74 1960 0.639 0.617 1961 0.361 0.489 1962 0.224 0.246 1963 0.308 0.313 1964 0.405 0.382 1965 0.290 0.434 1966 0.279 0.307 1967 0.584 0.405 1968 0.364 0.384 1969 0.356 0.326 1970 0.294 0.304 1971 0.314 0.362 1972 0.704 0.682 1973 0.320 0.439 1974 0.347 0.354 1975 0.470 0.371 1976 0.340 0.305 1977 0.040 0.291 1978 0.298 0.323 1979 0.180 0.345 1980 0.667 0.649 1981 0.267 0.344 1982 0.513 0.732 1983 0.460 0.340 1984 0.284 0.257 1985 0.168 0.317 1986 0.744 0.349 1987 0.658 0.602 1988 0.260 0.273 1989 0.169 0.255 1990 1.376 0.740 1991 0.829 0.733 1992 0.320 0.280 1993 0.333 0.223 1994 0.112 0.214 1995 0.477 0.432 1996 1.006 0.784 1997 0.841 0.759 1998 0.190 0.310 1999 0.788 0.655 2000 0.332 0.346 2001 0.060 0.327 2002 0.364 0.445 2003 0.464 0.343 2004 0.601 0.823 2005 0.431 0.320 2006 0.508 0.516 2007 1.021 1.030 2008 1.318 0.774 2009 0.647 0.476 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #5 Rank Predeveloped Mitigated 1 1.3760 1.0301 2 1.3175 0.8376 3 1.0214 0.8228 4 1.0058 0.7844 BP Model B 12/7/2023 10:19:49 AM Page 75 5 0.9452 0.7737 6 0.8408 0.7585 7 0.8285 0.7397 8 0.7885 0.7333 9 0.7440 0.7324 10 0.7039 0.6819 11 0.6671 0.6550 12 0.6581 0.6489 13 0.6469 0.6172 14 0.6391 0.6020 15 0.6007 0.5200 16 0.5899 0.5163 17 0.5837 0.4891 18 0.5258 0.4760 19 0.5128 0.4450 20 0.5082 0.4387 21 0.4772 0.4344 22 0.4702 0.4323 23 0.4694 0.4053 24 0.4640 0.4021 25 0.4597 0.4004 26 0.4310 0.3836 27 0.4268 0.3819 28 0.4217 0.3712 29 0.4055 0.3624 30 0.3788 0.3611 31 0.3699 0.3540 32 0.3661 0.3488 33 0.3641 0.3462 34 0.3637 0.3448 35 0.3606 0.3441 36 0.3562 0.3428 37 0.3471 0.3396 38 0.3400 0.3374 39 0.3328 0.3269 40 0.3319 0.3260 41 0.3198 0.3233 42 0.3195 0.3204 43 0.3141 0.3173 44 0.3080 0.3133 45 0.2983 0.3099 46 0.2979 0.3071 47 0.2937 0.3051 48 0.2903 0.3049 49 0.2838 0.3042 50 0.2791 0.3030 51 0.2666 0.2907 52 0.2597 0.2876 53 0.2409 0.2848 54 0.2244 0.2805 55 0.1902 0.2734 56 0.1802 0.2570 57 0.1694 0.2547 58 0.1684 0.2518 59 0.1118 0.2462 60 0.0595 0.2229 61 0.0405 0.2139 BP Model B 12/7/2023 10:19:49 AM Page 77 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2146 17678 17143 96 Pass 0.2231 16170 14298 88 Pass 0.2315 15026 12694 84 Pass 0.2400 13965 11612 83 Pass 0.2484 12857 10694 83 Pass 0.2569 11918 10098 84 Pass 0.2653 10928 9441 86 Pass 0.2738 10173 8945 87 Pass 0.2822 9396 8303 88 Pass 0.2907 8782 7781 88 Pass 0.2991 8153 7221 88 Pass 0.3076 7632 6752 88 Pass 0.3160 7058 6295 89 Pass 0.3244 6605 5908 89 Pass 0.3329 6186 5572 90 Pass 0.3413 5788 5180 89 Pass 0.3498 5461 4896 89 Pass 0.3582 5108 4577 89 Pass 0.3667 4825 4327 89 Pass 0.3751 4528 4081 90 Pass 0.3836 4267 3865 90 Pass 0.3920 4017 3623 90 Pass 0.4005 3799 3416 89 Pass 0.4089 3566 3219 90 Pass 0.4174 3345 3018 90 Pass 0.4258 3153 2870 91 Pass 0.4343 2954 2704 91 Pass 0.4427 2793 2558 91 Pass 0.4512 2599 2415 92 Pass 0.4596 2455 2282 92 Pass 0.4681 2304 2147 93 Pass 0.4765 2165 2025 93 Pass 0.4850 2045 1917 93 Pass 0.4934 1906 1786 93 Pass 0.5019 1798 1667 92 Pass 0.5103 1694 1574 92 Pass 0.5188 1597 1508 94 Pass 0.5272 1483 1431 96 Pass 0.5356 1387 1358 97 Pass 0.5441 1292 1280 99 Pass 0.5525 1225 1218 99 Pass 0.5610 1160 1157 99 Pass 0.5694 1098 1082 98 Pass 0.5779 1052 1001 95 Pass 0.5863 997 922 92 Pass 0.5948 933 863 92 Pass 0.6032 884 777 87 Pass 0.6117 841 714 84 Pass 0.6201 789 634 80 Pass 0.6286 744 571 76 Pass 0.6370 713 516 72 Pass 0.6455 673 464 68 Pass 0.6539 634 424 66 Pass BP Model B 12/7/2023 10:19:49 AM Page 78 0.6624 596 394 66 Pass 0.6708 569 372 65 Pass 0.6793 539 341 63 Pass 0.6877 500 320 64 Pass 0.6962 473 306 64 Pass 0.7046 437 288 65 Pass 0.7131 399 264 66 Pass 0.7215 370 240 64 Pass 0.7300 350 224 64 Pass 0.7384 324 205 63 Pass 0.7468 298 189 63 Pass 0.7553 273 173 63 Pass 0.7637 257 155 60 Pass 0.7722 235 139 59 Pass 0.7806 218 127 58 Pass 0.7891 195 120 61 Pass 0.7975 181 105 58 Pass 0.8060 158 95 60 Pass 0.8144 145 90 62 Pass 0.8229 131 78 59 Pass 0.8313 119 69 57 Pass 0.8398 110 66 60 Pass 0.8482 97 62 63 Pass 0.8567 91 59 64 Pass 0.8651 82 56 68 Pass 0.8736 76 51 67 Pass 0.8820 68 46 67 Pass 0.8905 61 44 72 Pass 0.8989 55 43 78 Pass 0.9074 48 40 83 Pass 0.9158 42 39 92 Pass 0.9243 38 36 94 Pass 0.9327 33 29 87 Pass 0.9412 27 24 88 Pass 0.9496 22 24 109 Pass 0.9580 21 23 109 Pass 0.9665 20 22 110 Pass 0.9749 19 21 110 Pass 0.9834 17 14 82 Pass 0.9918 14 10 71 Pass 1.0003 12 5 41 Pass 1.0087 9 2 22 Pass 1.0172 4 1 25 Pass 1.0256 3 1 33 Pass 1.0341 3 0 0 Pass 1.0425 3 0 0 Pass 1.0510 3 0 0 Pass BP Model B 12/7/2023 10:19:49 AM Page 79 Water Quality Water Quality BMP Flow and Volume for POC #5 On-line facility volume:0.3611 acre-feet On-line facility target flow:0.1843 cfs. Adjusted for 15 min:0.1843 cfs. Off-line facility target flow:0.1264 cfs. Adjusted for 15 min:0.1264 cfs. BP Model B 12/7/2023 10:19:49 AM Page 80 LID Report BP Model B 12/7/2023 10:19:49 AM Page 81 POC 6 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #6 Total Pervious Area:1.57 Total Impervious Area:5.82 Mitigated Landuse Totals for POC #6 Total Pervious Area:1.57 Total Impervious Area:5.82 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 2.319214 5 year 2.965594 10 year 3.408932 25 year 3.988285 50 year 4.434601 100 year 4.894093 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 2.319214 5 year 2.965594 10 year 3.408932 25 year 3.988285 50 year 4.434601 100 year 4.894093 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 3.102 3.102 1950 3.142 3.142 1951 1.933 1.933 1952 1.614 1.614 1953 1.744 1.744 1954 1.889 1.889 1955 2.118 2.118 1956 2.090 2.090 1957 2.434 2.434 1958 1.899 1.899 1959 1.881 1.881 BP Model B 12/7/2023 10:20:26 AM Page 82 1960 1.997 1.997 1961 2.061 2.061 1962 1.733 1.733 1963 1.995 1.995 1964 1.878 1.878 1965 2.523 2.523 1966 1.629 1.629 1967 2.826 2.826 1968 3.218 3.218 1969 2.295 2.295 1970 2.165 2.165 1971 2.583 2.583 1972 2.796 2.796 1973 1.542 1.542 1974 2.389 2.389 1975 2.592 2.592 1976 1.849 1.849 1977 1.890 1.890 1978 2.322 2.322 1979 3.189 3.189 1980 3.149 3.149 1981 2.409 2.409 1982 3.466 3.466 1983 2.718 2.718 1984 1.753 1.753 1985 2.411 2.411 1986 2.047 2.047 1987 3.144 3.144 1988 1.877 1.877 1989 2.348 2.348 1990 4.544 4.544 1991 3.528 3.528 1992 1.736 1.736 1993 1.474 1.474 1994 1.567 1.567 1995 2.127 2.127 1996 2.377 2.377 1997 2.277 2.277 1998 2.205 2.205 1999 4.719 4.719 2000 2.308 2.308 2001 2.440 2.440 2002 3.047 3.047 2003 2.368 2.368 2004 4.391 4.391 2005 2.013 2.013 2006 1.799 1.799 2007 4.129 4.129 2008 3.464 3.464 2009 2.872 2.872 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #6 Rank Predeveloped Mitigated 1 4.7187 4.7187 2 4.5445 4.5445 3 4.3912 4.3912 4 4.1285 4.1285 BP Model B 12/7/2023 10:20:26 AM Page 83 5 3.5276 3.5276 6 3.4656 3.4656 7 3.4641 3.4641 8 3.2183 3.2183 9 3.1886 3.1886 10 3.1490 3.1490 11 3.1442 3.1442 12 3.1419 3.1419 13 3.1017 3.1017 14 3.0475 3.0475 15 2.8724 2.8724 16 2.8263 2.8263 17 2.7964 2.7964 18 2.7179 2.7179 19 2.5925 2.5925 20 2.5835 2.5835 21 2.5232 2.5232 22 2.4400 2.4400 23 2.4338 2.4338 24 2.4113 2.4113 25 2.4093 2.4093 26 2.3891 2.3891 27 2.3773 2.3773 28 2.3683 2.3683 29 2.3477 2.3477 30 2.3218 2.3218 31 2.3079 2.3079 32 2.2945 2.2945 33 2.2772 2.2772 34 2.2049 2.2049 35 2.1649 2.1649 36 2.1268 2.1268 37 2.1178 2.1178 38 2.0904 2.0904 39 2.0607 2.0607 40 2.0471 2.0471 41 2.0129 2.0129 42 1.9968 1.9968 43 1.9951 1.9951 44 1.9327 1.9327 45 1.8985 1.8985 46 1.8899 1.8899 47 1.8890 1.8890 48 1.8807 1.8807 49 1.8781 1.8781 50 1.8773 1.8773 51 1.8487 1.8487 52 1.7994 1.7994 53 1.7525 1.7525 54 1.7442 1.7442 55 1.7361 1.7361 56 1.7333 1.7333 57 1.6286 1.6286 58 1.6144 1.6144 59 1.5666 1.5666 60 1.5419 1.5419 61 1.4740 1.4740 BP Model B 12/7/2023 10:20:26 AM Page 85 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 1.1596 1707 1707 100 Pass 1.1927 1565 1565 100 Pass 1.2258 1418 1418 100 Pass 1.2588 1277 1277 100 Pass 1.2919 1139 1139 100 Pass 1.3250 1043 1043 100 Pass 1.3581 954 954 100 Pass 1.3912 876 876 100 Pass 1.4243 802 802 100 Pass 1.4573 735 735 100 Pass 1.4904 674 674 100 Pass 1.5235 624 624 100 Pass 1.5566 573 573 100 Pass 1.5897 536 536 100 Pass 1.6227 501 501 100 Pass 1.6558 453 453 100 Pass 1.6889 419 419 100 Pass 1.7220 390 390 100 Pass 1.7551 362 362 100 Pass 1.7881 349 349 100 Pass 1.8212 320 320 100 Pass 1.8543 299 299 100 Pass 1.8874 275 275 100 Pass 1.9205 257 257 100 Pass 1.9535 239 239 100 Pass 1.9866 226 226 100 Pass 2.0197 207 207 100 Pass 2.0528 196 196 100 Pass 2.0859 185 185 100 Pass 2.1189 169 169 100 Pass 2.1520 158 158 100 Pass 2.1851 148 148 100 Pass 2.2182 142 142 100 Pass 2.2513 131 131 100 Pass 2.2844 125 125 100 Pass 2.3174 116 116 100 Pass 2.3505 111 111 100 Pass 2.3836 104 104 100 Pass 2.4167 95 95 100 Pass 2.4498 88 88 100 Pass 2.4828 82 82 100 Pass 2.5159 82 82 100 Pass 2.5490 79 79 100 Pass 2.5821 78 78 100 Pass 2.6152 73 73 100 Pass 2.6482 69 69 100 Pass 2.6813 64 64 100 Pass 2.7144 62 62 100 Pass 2.7475 58 58 100 Pass 2.7806 55 55 100 Pass 2.8136 53 53 100 Pass 2.8467 48 48 100 Pass 2.8798 47 47 100 Pass BP Model B 12/7/2023 10:20:26 AM Page 86 2.9129 45 45 100 Pass 2.9460 41 41 100 Pass 2.9790 40 40 100 Pass 3.0121 39 39 100 Pass 3.0452 35 35 100 Pass 3.0783 31 31 100 Pass 3.1114 29 29 100 Pass 3.1445 27 27 100 Pass 3.1775 23 23 100 Pass 3.2106 22 22 100 Pass 3.2437 19 19 100 Pass 3.2768 18 18 100 Pass 3.3099 16 16 100 Pass 3.3429 16 16 100 Pass 3.3760 15 15 100 Pass 3.4091 13 13 100 Pass 3.4422 13 13 100 Pass 3.4753 10 10 100 Pass 3.5083 9 9 100 Pass 3.5414 8 8 100 Pass 3.5745 8 8 100 Pass 3.6076 8 8 100 Pass 3.6407 8 8 100 Pass 3.6737 8 8 100 Pass 3.7068 8 8 100 Pass 3.7399 8 8 100 Pass 3.7730 8 8 100 Pass 3.8061 8 8 100 Pass 3.8391 8 8 100 Pass 3.8722 8 8 100 Pass 3.9053 7 7 100 Pass 3.9384 7 7 100 Pass 3.9715 7 7 100 Pass 4.0046 7 7 100 Pass 4.0376 7 7 100 Pass 4.0707 6 6 100 Pass 4.1038 6 6 100 Pass 4.1369 5 5 100 Pass 4.1700 5 5 100 Pass 4.2030 4 4 100 Pass 4.2361 4 4 100 Pass 4.2692 4 4 100 Pass 4.3023 4 4 100 Pass 4.3354 3 3 100 Pass 4.3684 3 3 100 Pass 4.4015 2 2 100 Pass 4.4346 2 2 100 Pass BP Model B 12/7/2023 10:20:26 AM Page 87 Water Quality Water Quality BMP Flow and Volume for POC #6 On-line facility volume:0.7627 acre-feet On-line facility target flow:0.9348 cfs. Adjusted for 15 min:0.9348 cfs. Off-line facility target flow:0.5262 cfs. Adjusted for 15 min:0.5262 cfs. BP Model B 12/7/2023 10:20:26 AM Page 88 LID Report BP Model B 12/7/2023 10:20:26 AM Page 91 Appendix Predeveloped Schematic BP Model B 12/7/2023 10:20:27 AM Page 92 Mitigated Schematic BP Model B 12/7/2023 10:20:28 AM Page 117 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT BP Model C 1/16/2023 11:53:20 AM Page 2 General Model Information Project Name:BP Model C Site Name:Business Park Site Address:Model C - Pond 5 Reduced City: Report Date:1/16/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Low Flow Threshold for POC6:50 Percent of the 2 Year High Flow Threshold for POC6:50 Year BP Model C 1/16/2023 11:53:20 AM Page 3 Landuse Basin Data Predeveloped Land Use Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.93 Pervious Total 0.93 Impervious Land Use acre Impervious Total 0 Basin Total 0.93 Element Flows To: Surface Interflow Groundwater BP Model C 1/16/2023 11:53:20 AM Page 4 PreDev - Basin 5 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.92 Pervious Total 12.92 Impervious Land Use acre Impervious Total 0 Basin Total 12.92 Element Flows To: Surface Interflow Groundwater BP Model C 1/16/2023 11:53:20 AM Page 5 PreDev - Basin 5 - WQ Node Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 5.82 Impervious Total 5.82 Basin Total 7.39 Element Flows To: Surface Interflow Groundwater BP Model C 1/16/2023 11:53:20 AM Page 6 Mitigated Land Use Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.93 Pervious Total 0.93 Impervious Land Use acre Impervious Total 0 Basin Total 0.93 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model C 1/16/2023 11:53:20 AM Page 7 Dev - Basin 5 - Roof Only Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 5.53 Impervious Total 5.53 Basin Total 5.53 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model C 1/16/2023 11:53:20 AM Page 8 Dev - Basin 5 - PGIS Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 5.82 Impervious Total 5.82 Basin Total 7.39 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model C 1/16/2023 11:53:20 AM Page 10 Mitigated Routing Pond 5 - 4:1 SS Bottom Length:200.00 ft. Bottom Width:85.70 ft. Depth:4.5 ft. Volume at riser head:1.7196 acre-feet. Side slope 1:4 To 1 Side slope 2:4 To 1 Side slope 3:4 To 1 Side slope 4:4 To 1 Discharge Structure Riser Height:3.5 ft. Riser Diameter:24 in. Notch Type:Rectangular Notch Width:0.500 ft. Notch Height:1.500 ft. Orifice 1 Diameter:3 in.Elevation:0 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.393 0.000 0.000 0.000 0.0500 0.396 0.019 0.054 0.000 0.1000 0.398 0.039 0.077 0.000 0.1500 0.401 0.059 0.094 0.000 0.2000 0.404 0.079 0.109 0.000 0.2500 0.406 0.100 0.122 0.000 0.3000 0.409 0.120 0.133 0.000 0.3500 0.412 0.141 0.144 0.000 0.4000 0.414 0.161 0.154 0.000 0.4500 0.417 0.182 0.163 0.000 0.5000 0.420 0.203 0.172 0.000 0.5500 0.422 0.224 0.181 0.000 0.6000 0.425 0.245 0.189 0.000 0.6500 0.428 0.267 0.196 0.000 0.7000 0.430 0.288 0.204 0.000 0.7500 0.433 0.310 0.211 0.000 0.8000 0.436 0.331 0.218 0.000 0.8500 0.439 0.353 0.225 0.000 0.9000 0.441 0.375 0.231 0.000 0.9500 0.444 0.397 0.238 0.000 1.0000 0.447 0.420 0.244 0.000 1.0500 0.450 0.442 0.250 0.000 1.1000 0.453 0.465 0.256 0.000 1.1500 0.455 0.487 0.261 0.000 1.2000 0.458 0.510 0.267 0.000 1.2500 0.461 0.533 0.273 0.000 1.3000 0.464 0.556 0.278 0.000 1.3500 0.467 0.580 0.283 0.000 1.4000 0.469 0.603 0.289 0.000 1.4500 0.472 0.627 0.294 0.000 1.5000 0.475 0.650 0.299 0.000 1.5500 0.478 0.674 0.304 0.000 BP Model C 1/16/2023 11:53:20 AM Page 11 1.6000 0.481 0.698 0.308 0.000 1.6500 0.484 0.722 0.313 0.000 1.7000 0.486 0.747 0.318 0.000 1.7500 0.489 0.771 0.323 0.000 1.8000 0.492 0.796 0.327 0.000 1.8500 0.495 0.820 0.332 0.000 1.9000 0.498 0.845 0.336 0.000 1.9500 0.501 0.870 0.341 0.000 2.0000 0.504 0.895 0.345 0.000 2.0500 0.507 0.921 0.368 0.000 2.1000 0.510 0.946 0.405 0.000 2.1500 0.513 0.972 0.451 0.000 2.2000 0.516 0.997 0.505 0.000 2.2500 0.519 1.023 0.564 0.000 2.3000 0.521 1.049 0.627 0.000 2.3500 0.524 1.075 0.695 0.000 2.4000 0.527 1.102 0.765 0.000 2.4500 0.530 1.128 0.839 0.000 2.5000 0.533 1.155 0.916 0.000 2.5500 0.536 1.182 0.994 0.000 2.6000 0.539 1.209 1.074 0.000 2.6500 0.542 1.236 1.156 0.000 2.7000 0.545 1.263 1.239 0.000 2.7500 0.548 1.290 1.324 0.000 2.8000 0.551 1.318 1.409 0.000 2.8500 0.555 1.345 1.495 0.000 2.9000 0.558 1.373 1.581 0.000 2.9500 0.561 1.401 1.668 0.000 3.0000 0.564 1.429 1.755 0.000 3.0500 0.567 1.458 1.859 0.000 3.1000 0.570 1.486 1.966 0.000 3.1500 0.573 1.515 2.076 0.000 3.2000 0.576 1.543 2.187 0.000 3.2500 0.579 1.572 2.301 0.000 3.3000 0.582 1.601 2.418 0.000 3.3500 0.585 1.631 2.536 0.000 3.4000 0.588 1.660 2.656 0.000 3.4500 0.592 1.689 3.524 0.000 3.5000 0.595 1.719 3.687 0.000 3.5500 0.598 1.749 3.928 0.000 3.6000 0.601 1.779 4.364 0.000 3.6500 0.604 1.809 4.926 0.000 3.7000 0.607 1.839 5.587 0.000 3.7500 0.610 1.870 6.326 0.000 3.8000 0.614 1.900 7.127 0.000 3.8500 0.617 1.931 7.974 0.000 3.9000 0.620 1.962 8.847 0.000 3.9500 0.623 1.993 9.731 0.000 4.0000 0.626 2.025 10.60 0.000 4.0500 0.630 2.056 11.45 0.000 4.1000 0.633 2.088 12.26 0.000 4.1500 0.636 2.119 13.01 0.000 4.2000 0.639 2.151 13.69 0.000 4.2500 0.643 2.183 14.30 0.000 4.3000 0.646 2.216 14.82 0.000 4.3500 0.649 2.248 15.26 0.000 4.4000 0.652 2.280 15.63 0.000 4.4500 0.656 2.313 15.93 0.000 BP Model C 1/16/2023 11:53:20 AM Page 17 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:13.85 Total Impervious Area:0 Mitigated Landuse Totals for POC #5 Total Pervious Area:2.5 Total Impervious Area:11.35 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.407202 5 year 0.639526 10 year 0.771188 25 year 0.910672 50 year 0.996986 100 year 1.070399 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 1.223539 5 year 2.100616 10 year 2.803236 25 year 3.830698 50 year 4.698739 100 year 5.655997 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.400 1.096 1950 0.499 1.489 1951 0.897 2.044 1952 0.283 0.576 1953 0.229 0.913 1954 0.351 0.909 1955 0.560 1.822 1956 0.445 1.414 1957 0.359 1.595 1958 0.405 1.136 1959 0.347 1.214 BP Model C 1/16/2023 11:53:52 AM Page 18 1960 0.606 1.809 1961 0.342 1.105 1962 0.213 0.349 1963 0.292 1.116 1964 0.385 0.826 1965 0.275 1.157 1966 0.265 0.641 1967 0.554 1.730 1968 0.345 0.818 1969 0.338 1.034 1970 0.279 0.873 1971 0.298 1.333 1972 0.668 1.659 1973 0.303 0.902 1974 0.329 0.885 1975 0.446 1.747 1976 0.322 1.013 1977 0.038 0.565 1978 0.283 0.895 1979 0.171 0.382 1980 0.633 1.860 1981 0.253 0.743 1982 0.486 2.681 1983 0.436 1.280 1984 0.269 0.480 1985 0.160 1.047 1986 0.706 2.249 1987 0.624 2.443 1988 0.246 0.719 1989 0.161 0.493 1990 1.305 4.545 1991 0.786 3.556 1992 0.303 0.701 1993 0.316 0.947 1994 0.106 0.327 1995 0.453 1.437 1996 0.954 2.385 1997 0.798 2.258 1998 0.180 1.169 1999 0.748 1.826 2000 0.315 1.116 2001 0.056 0.553 2002 0.345 2.363 2003 0.440 0.602 2004 0.570 5.452 2005 0.409 1.532 2006 0.482 1.396 2007 0.969 4.303 2008 1.250 4.641 2009 0.614 2.311 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #5 Rank Predeveloped Mitigated 1 1.3053 5.4515 2 1.2499 4.6406 3 0.9689 4.5445 4 0.9541 4.3026 BP Model C 1/16/2023 11:53:52 AM Page 19 5 0.8967 3.5556 6 0.7976 2.6814 7 0.7860 2.4433 8 0.7479 2.3847 9 0.7058 2.3633 10 0.6678 2.3110 11 0.6328 2.2581 12 0.6243 2.2486 13 0.6137 2.0441 14 0.6063 1.8602 15 0.5699 1.8259 16 0.5596 1.8221 17 0.5537 1.8090 18 0.4988 1.7472 19 0.4864 1.7299 20 0.4821 1.6591 21 0.4527 1.5947 22 0.4461 1.5319 23 0.4453 1.4888 24 0.4401 1.4366 25 0.4361 1.4137 26 0.4088 1.3956 27 0.4049 1.3335 28 0.4000 1.2805 29 0.3846 1.2141 30 0.3594 1.1693 31 0.3509 1.1570 32 0.3473 1.1355 33 0.3454 1.1159 34 0.3450 1.1156 35 0.3421 1.1047 36 0.3379 1.0956 37 0.3292 1.0473 38 0.3225 1.0339 39 0.3157 1.0127 40 0.3148 0.9466 41 0.3033 0.9133 42 0.3031 0.9094 43 0.2980 0.9022 44 0.2922 0.8952 45 0.2830 0.8851 46 0.2826 0.8728 47 0.2786 0.8262 48 0.2754 0.8176 49 0.2692 0.7431 50 0.2648 0.7186 51 0.2529 0.7011 52 0.2464 0.6406 53 0.2285 0.6024 54 0.2128 0.5758 55 0.1804 0.5646 56 0.1710 0.5531 57 0.1607 0.4928 58 0.1598 0.4798 59 0.1061 0.3820 60 0.0565 0.3486 61 0.0384 0.3271 BP Model C 1/16/2023 11:55:36 AM Page 25 POC 6 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #6 Total Pervious Area:1.57 Total Impervious Area:5.82 Mitigated Landuse Totals for POC #6 Total Pervious Area:1.57 Total Impervious Area:5.82 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 2.319214 5 year 2.965594 10 year 3.408932 25 year 3.988285 50 year 4.434601 100 year 4.894093 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 2.319214 5 year 2.965594 10 year 3.408932 25 year 3.988285 50 year 4.434601 100 year 4.894093 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 3.102 3.102 1950 3.142 3.142 1951 1.933 1.933 1952 1.614 1.614 1953 1.744 1.744 1954 1.889 1.889 1955 2.118 2.118 1956 2.090 2.090 1957 2.434 2.434 1958 1.899 1.899 1959 1.881 1.881 BP Model C 1/16/2023 11:56:07 AM Page 26 1960 1.997 1.997 1961 2.061 2.061 1962 1.733 1.733 1963 1.995 1.995 1964 1.878 1.878 1965 2.523 2.523 1966 1.629 1.629 1967 2.826 2.826 1968 3.218 3.218 1969 2.295 2.295 1970 2.165 2.165 1971 2.583 2.583 1972 2.796 2.796 1973 1.542 1.542 1974 2.389 2.389 1975 2.592 2.592 1976 1.849 1.849 1977 1.890 1.890 1978 2.322 2.322 1979 3.189 3.189 1980 3.149 3.149 1981 2.409 2.409 1982 3.466 3.466 1983 2.718 2.718 1984 1.753 1.753 1985 2.411 2.411 1986 2.047 2.047 1987 3.144 3.144 1988 1.877 1.877 1989 2.348 2.348 1990 4.544 4.544 1991 3.528 3.528 1992 1.736 1.736 1993 1.474 1.474 1994 1.567 1.567 1995 2.127 2.127 1996 2.377 2.377 1997 2.277 2.277 1998 2.205 2.205 1999 4.719 4.719 2000 2.308 2.308 2001 2.440 2.440 2002 3.047 3.047 2003 2.368 2.368 2004 4.391 4.391 2005 2.013 2.013 2006 1.799 1.799 2007 4.129 4.129 2008 3.464 3.464 2009 2.872 2.872 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #6 Rank Predeveloped Mitigated 1 4.7187 4.7187 2 4.5445 4.5445 3 4.3912 4.3912 4 4.1285 4.1285 BP Model C 1/16/2023 11:56:07 AM Page 27 5 3.5276 3.5276 6 3.4656 3.4656 7 3.4641 3.4641 8 3.2183 3.2183 9 3.1886 3.1886 10 3.1490 3.1490 11 3.1442 3.1442 12 3.1419 3.1419 13 3.1017 3.1017 14 3.0475 3.0475 15 2.8724 2.8724 16 2.8263 2.8263 17 2.7964 2.7964 18 2.7179 2.7179 19 2.5925 2.5925 20 2.5835 2.5835 21 2.5232 2.5232 22 2.4400 2.4400 23 2.4338 2.4338 24 2.4113 2.4113 25 2.4093 2.4093 26 2.3891 2.3891 27 2.3773 2.3773 28 2.3683 2.3683 29 2.3477 2.3477 30 2.3218 2.3218 31 2.3079 2.3079 32 2.2945 2.2945 33 2.2772 2.2772 34 2.2049 2.2049 35 2.1649 2.1649 36 2.1268 2.1268 37 2.1178 2.1178 38 2.0904 2.0904 39 2.0607 2.0607 40 2.0471 2.0471 41 2.0129 2.0129 42 1.9968 1.9968 43 1.9951 1.9951 44 1.9327 1.9327 45 1.8985 1.8985 46 1.8899 1.8899 47 1.8890 1.8890 48 1.8807 1.8807 49 1.8781 1.8781 50 1.8773 1.8773 51 1.8487 1.8487 52 1.7994 1.7994 53 1.7525 1.7525 54 1.7442 1.7442 55 1.7361 1.7361 56 1.7333 1.7333 57 1.6286 1.6286 58 1.6144 1.6144 59 1.5666 1.5666 60 1.5419 1.5419 61 1.4740 1.4740 BP Model C 1/16/2023 11:56:07 AM Page 29 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 1.1596 1707 1707 100 Pass 1.1927 1565 1565 100 Pass 1.2258 1418 1418 100 Pass 1.2588 1277 1277 100 Pass 1.2919 1139 1139 100 Pass 1.3250 1043 1043 100 Pass 1.3581 954 954 100 Pass 1.3912 876 876 100 Pass 1.4243 802 802 100 Pass 1.4573 735 735 100 Pass 1.4904 674 674 100 Pass 1.5235 624 624 100 Pass 1.5566 573 573 100 Pass 1.5897 536 536 100 Pass 1.6227 501 501 100 Pass 1.6558 453 453 100 Pass 1.6889 419 419 100 Pass 1.7220 390 390 100 Pass 1.7551 362 362 100 Pass 1.7881 349 349 100 Pass 1.8212 320 320 100 Pass 1.8543 299 299 100 Pass 1.8874 275 275 100 Pass 1.9205 257 257 100 Pass 1.9535 239 239 100 Pass 1.9866 226 226 100 Pass 2.0197 207 207 100 Pass 2.0528 196 196 100 Pass 2.0859 185 185 100 Pass 2.1189 169 169 100 Pass 2.1520 158 158 100 Pass 2.1851 148 148 100 Pass 2.2182 142 142 100 Pass 2.2513 131 131 100 Pass 2.2844 125 125 100 Pass 2.3174 116 116 100 Pass 2.3505 111 111 100 Pass 2.3836 104 104 100 Pass 2.4167 95 95 100 Pass 2.4498 88 88 100 Pass 2.4828 82 82 100 Pass 2.5159 82 82 100 Pass 2.5490 79 79 100 Pass 2.5821 78 78 100 Pass 2.6152 73 73 100 Pass 2.6482 69 69 100 Pass 2.6813 64 64 100 Pass 2.7144 62 62 100 Pass 2.7475 58 58 100 Pass 2.7806 55 55 100 Pass 2.8136 53 53 100 Pass 2.8467 48 48 100 Pass 2.8798 47 47 100 Pass BP Model C 1/16/2023 11:56:07 AM Page 30 2.9129 45 45 100 Pass 2.9460 41 41 100 Pass 2.9790 40 40 100 Pass 3.0121 39 39 100 Pass 3.0452 35 35 100 Pass 3.0783 31 31 100 Pass 3.1114 29 29 100 Pass 3.1445 27 27 100 Pass 3.1775 23 23 100 Pass 3.2106 22 22 100 Pass 3.2437 19 19 100 Pass 3.2768 18 18 100 Pass 3.3099 16 16 100 Pass 3.3429 16 16 100 Pass 3.3760 15 15 100 Pass 3.4091 13 13 100 Pass 3.4422 13 13 100 Pass 3.4753 10 10 100 Pass 3.5083 9 9 100 Pass 3.5414 8 8 100 Pass 3.5745 8 8 100 Pass 3.6076 8 8 100 Pass 3.6407 8 8 100 Pass 3.6737 8 8 100 Pass 3.7068 8 8 100 Pass 3.7399 8 8 100 Pass 3.7730 8 8 100 Pass 3.8061 8 8 100 Pass 3.8391 8 8 100 Pass 3.8722 8 8 100 Pass 3.9053 7 7 100 Pass 3.9384 7 7 100 Pass 3.9715 7 7 100 Pass 4.0046 7 7 100 Pass 4.0376 7 7 100 Pass 4.0707 6 6 100 Pass 4.1038 6 6 100 Pass 4.1369 5 5 100 Pass 4.1700 5 5 100 Pass 4.2030 4 4 100 Pass 4.2361 4 4 100 Pass 4.2692 4 4 100 Pass 4.3023 4 4 100 Pass 4.3354 3 3 100 Pass 4.3684 3 3 100 Pass 4.4015 2 2 100 Pass 4.4346 2 2 100 Pass BP Model C 1/16/2023 11:56:07 AM Page 31 Water Quality Water Quality BMP Flow and Volume for POC #6 On-line facility volume:0.7628 acre-feet On-line facility target flow:0.9348 cfs. Adjusted for 15 min:0.9348 cfs. Off-line facility target flow:0.5262 cfs. Adjusted for 15 min:0.5262 cfs. BP Model C 1/16/2023 11:56:07 AM Page 35 Appendix Predeveloped Schematic BP Model C 1/16/2023 11:56:08 AM Page 36 Mitigated Schematic BP Model C 1/16/2023 11:56:09 AM Page 49 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Project Description Friction Method Manning Formula Solve For Discharge Input Data Roughness Coefficient 0.013 Channel Slope 0.03200 ft/ft Normal Depth 1.00 ft Diameter 1.00 ft Results Discharge 6.37 ft³/s Flow Area 0.79 ft² Wetted Perimeter 3.14 ft Hydraulic Radius 0.25 ft Top Width 0.00 ft Critical Depth 0.96 ft Percent Full 100.0 % Critical Slope 0.02798 ft/ft Velocity 8.11 ft/s Velocity Head 1.02 ft Specific Energy 2.02 ft Froude Number 0.00 Maximum Discharge 6.86 ft³/s Discharge Full 6.37 ft³/s Slope Full 0.03200 ft/ft Flow Type SubCritical GVF Input Data Downstream Depth 0.00 ft Length 0.00 ft Number Of Steps 0 GVF Output Data Upstream Depth 0.00 ft Profile Description Profile Headloss 0.00 ft Average End Depth Over Rise 0.00 % Normal Depth Over Rise 100.00 % Downstream Velocity Infinity ft/s 12" Culvert #1 9/15/2017 11:31:13 AM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of1Page GVF Output Data Upstream Velocity Infinity ft/s Normal Depth 1.00 ft Critical Depth 0.96 ft Channel Slope 0.03200 ft/ft Critical Slope 0.02798 ft/ft 12" Culvert #1 9/15/2017 11:31:13 AM Bentley Systems, Inc. Haestad Methods Solution CenterBentley FlowMaster V8i (SELECTseries 1) [08.11.01.03] 27 Siemons Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 2of2Page Appendix C Woodbridge Business Park TIR Addendum MEMORANDUM TO:KEVIN PETERSON, CITY OF FEDERAL WAY FROM: LAURA BARTENHAGEN RE:WOODBRIDGE BUSINESS PARK TIR ADDENDUM JOB #:1886-001-016-0016 DATE: NOVEMBER 10, 2021 On behalf of Federal Way Campus, LLC, ESM Consulting Engineers, LLC is providing the following supplemental information to demonstrate compliance and consistency with the 1991 Executive Proposed Basin Plan - Hylebos Creek and Lower Puget Sound (Basin Plan) for the Woodbridge Business Park project, as an addendum to the Woodbridge Business Park TIR. In an effort to best address each basinwide (BW) recommendation, the applicable BW recommendations have been shown in their entirety in italics while the remaining BW recommendations have an abbreviated summary with page references to the Basin Plan. The associated compliance for each BW recommendation is shown in bold. 3.1 ZONING CONTROLS FOR STREAM CORRIDORS BW-1:Low Density Zoning Controls for Protection of Stream Corridors and Ravines This BW recommendation pertains to the areas within stream corridors that should be protected from development beyond a density limit and concerns the local jurisdictions. The full description for this recommendation is available starting on page 3-4 of the Basin Plan. The purpose of this BW recommendation is to provide low density zoning controls to protect stream corridors within specific regionally significant and locally significant resource areas (RSRAs and LSRAs). These resource areas are not identified on the proposed development property; therefore, this BW is not applicable for the project. 3.2 CONTROL OF VOLUME AND TIMING OF RUNOFF FROM DEVELOPING SITES BW-2:Basinwide Onsite Detention Standard This BW recommendation was copied from the Basin Plan (page 3-6) in its entirety because it is applicable to the project site. To control downstream or downslope impacts of new development, including public and private street and highways, onsite retention/detention (RID) facilities in the Hylebos Creek 2 and Lower Puget Sound basins should be designed to control the post-development 2- and 10-year flows to corresponding pre-development levels. The calculated storage volume should be increased by a safety factor or 30 percent to account for various uncertainties in the analysis and design. The design methodologies recommended are either a modification of the 1990 King County Design Manual or the use of a calibrated continuous hydrologic model. Following further modeling of these basins, it was determined that the existing Design Manual methodology would not enable development in the planning area to achieve the post- development run-off objectives of reducing peak 2-and 10-year flows to pre-developed levels. Therefore, one of the recommended methodologies includes modifications to the Design Manual methods. The modifications will produce a detention pond that reduces 2- and 10-year peak flows to pre-development rates. The modifications to the current manual include a 7-day design storm with a more representative distribution instead of a 24-hour storm and a more accurate method of determining the time of concentrations. For additional details regarding these modifications, contact King County SWM Basin Planning. The runoff mitigation standard discussed in this BW recommendation has been superseded since the 1998 King County Surface Water Design Manual (KCSWDM) and increased in the current 2016 KCSWDM. The project exceeds the BW-2 recommendation and is compliant and consistent with the more stringent BW-3 recommendation below. BW-3:Stream Protection Onsite Detention Standard This BW recommendation was copied from the Basin Plan (pages 3-6 to 3-9) in its entirety because it is applicable to the project site. In subcatchments where future flows are expected to have significant adverse impacts on stream stability and habitat, onsite detention ponds for new development, including public and private streets and highways, should be designed such that post-development flow peaks and durations are reduced to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year. In addition, the 100-year post- development peak flow should be reduced to the 100-year pre-development level. The recommended method of designing these detention ponds is a calibrated continuous hydrologic model, preferably HSPF. An alternative to using a continuous hydrologic model is SCS methods with a design release rate such that the post-developed 100-year flow is released at 70-percent of the pre-development 2-year rate. A 24-hour design storm, as described in the 1990 King County Design Manual, is recommended. Additional design methods may become available in the future. Contact King County SWM Basin Planning for additional details. See Figures 4.1.3, 4.2.3, and 4.5.3 for areas where this standard applies. Affected Entities: The Basinwide Onsite Detention Standard (BW-2) is a modification of the Design Manual. The design methodology of all entities currently using the Design Manual should be updated to include 7-day design storms and revised time of concentration calculations. 3 The revised methodology produces detention ponds that are between 50 percent and 100 percent larger, depending on site density. Milton currently utilizes a less stringent standard that requires design of onsite detention ponds to control the 10-year storm. To be consistent with the Basin Plan, it is recommended that Milton adopt the detention standard in BW-2. The Stream Protection Onsite Detention Standard (BW-3) applies to parts of five entities in the basins: King County and Milton in subcatchment H2 on tributary 0015 on the East Branch Hylebos Creek and in Tacoma, Pierce County, and Federal Way in subcatchments J2, J6, J7, and J8 that drain into upper Joes Creek and subcatchment WH3 in tributary 0013 which flows into West Branch Hylebos Creek. Presently no affected entity has this standard in place. To be consistent with the Basin Plan it is recommended that Federal Way, King County, Milton, Pierce County, and Tacoma adopt recommendation BW-3 in the areas indicated. As described in the TIR, the project complies with the current Level 3 Flow Control Mitigation Standard, as defined in the 2016 KCSWDM which meets the intent of this BW recommendation, to reduce flow peaks and durations to pre-development levels for flows greater than 50 percent of the 2-year and less than the 50-year, up to the 100-year storm event. Therefore, the project is compliant and consistent with this BW recommendation. 3.3 SENSITIVE AREA PROTECTION BW-4:Stream Buffers This BW recommendation pertains to the required buffers for Class 2 & 3 streams, RSRAs, and LSRAs. The full description for this recommendation is available starting on page 3-9 of the Basin Plan. RSRAs or LSRAs (per Figure 2.1.1 of the Basin Plan) and Class 2 streams are not present on the project site. BW-5:Wetland Buffers This BW recommendation was copied from the Basin Plan (page 3-10) in its entirety because it is applicable to the project site. At a minimum, the buffers should be 100 feet from the edge of Class 1 wetlands except for the west Hylebos Wetland RSRA and Spring Valley LSRA; 50 feet from Class 2, and 25 feet from Class 3 wetlands. The West Hylebos and Spring Valley Wetlands are the only wetlands that would not receive additional protection - from the shoreline management program; therefore these two wetlands should have a 150-foot buffer. The Project only contains Class 2 and 3 wetlands, based on the definitions provided in the basin study. The wetland buffers used for the Project as required by the 1994 FWCC exceed the buffer requirements outlined in this recommendation. Standard wetland buffers have been provided with their approved modifications, and are described in the Critical Areas Report and Proposed Mitigation Plan by Talasaea Consultants, Inc., dated 9 April 4 2020 and the Addendum to the 9 April 2020 Critical Areas Report and Proposed Mitigation Plan by Wet.land, LLC., dated 10 October 2021. BW-6:Livestock Access Control This BW recommendation was copied from the Basin Plan (page 3-10) in its entirety for brevity. Access to streams and wetlands should be limited by fencing livestock from riparian buffers or other equivalent means. Provisions can be made for access to watering points. There are no livestock in or adjacent to the project site; therefore, this BW recommendation is not applicable. BW-7:Limitations on Stream Crossings and Stream Modification or Relocation This BW recommendation pertains to the limits of stream modification during stream crossing efforts with roads and utilities. The full description for this recommendation is available starting on page 3-10 of the Basin Plan. The project does not propose any stream crossings; therefore, this BW recommendation is not applicable. BW-8:Clearing, Grading, and Filling Limitations This BW recommendation was copied from the Basin Plan (pages 3-13 to 3-14) in its entirety because it is applicable to the project site. 1.Filling of more than three feet in vertical depth or excavation of more than five feet in vertical depth, or any grading that involves more than100 cubic yards of material, should require a permit. In environmentally sensitive areas such as streams, wetlands, steep slopes, or their buffers, a permit should be required for grading of any quantity or dimension. The project will acquire acquiring a permit for clearing and grading activities. 2.Erosion, sedimentation, and stormwater controls consistent with the 1990 King County Surface Water Design Manual or updates, as adopted by the entity, should be required to be in place and inspected for appropriate installation before clearing, grading, or filling begins. Regular inspection of these controls should be required at specific phases of site work to ensure these controls are functioning as designed. The project is implementing erosion and sedimentation controls consistent with the current 2016 KCSWDM and the DOE NPDES permit. 3.Sites that have been cleared, graded, or filled in violation of current or prior standards should be fully restored before construction permits are issued. Particular attention should be paid to sites that may be filled with unauthorized solid wastes. Any large releases of sediment or spills that are documented as non- 5 compliance of permit conditions or cause water quality or habitat degradation should be fully compensated and restored before construction permits are issued. The project has not been previously cleared, graded, or filled in violation of current or prior standards. 4.Significant trees should be identified during the platting process and retained on all sites. Significant trees are coniferous trees eight inches in diameter or greater, or any deciduous tree, other than red alder, 12 inches or more diameter, each measured 54 inches above grade. A tree retention plan has been reviewed and approved by the City of Federal Way as part of the Process IV application. The tree retention plan includes a managed forest buffer that will preserve existing significant trees. 5.Significant natural vegetation should be retained. Significant natural vegetation is a concentration of vegetation with significant biological importance such as dense, mature native vegetation that supports local wildlife. A tree retention plan has been reviewed and approved by the City of Federal Way as part of the Process IV application that clearly documents the location of native trees to be retained across the Site. The tree retention plan includes areas of undisturbed natural vegetation that will be preserved and managed long-term. The areas of preserved natural vegetation will continue to support local wildlife, while the managed forest buffer will provide corridors for wildlife movement between this and other sites in the vicinity. 6.Areas with retained vegetation should be clearly and permanently marked on the site prior to starting site work, identified on all plat maps and title instruments, and have legally binding restrictions placed on them. The areas of retained vegetation and trees have been marked on the construction plans, and will be clearly delineated in the field prior to the start of site work. The project has addressed all 6 items in this BW recommendation; therefore, the project is compliant and consistent with this BW recommendation. BW-9:Seasonal Clearing and Grading Limits This BW recommendation was copied from the Basin Plan (pages 3-14 to 3-15) in its entirety because it is applicable to the project site. Bare ground associated with clearing, grading, utility installation, building construction, and other development activity should be completely revegetated by October 1 and not disturbed until the following March 31. Earth-moving or land clearing activity should not occur during this period, except for regular maintenance for public facilities and public agency response to emergencies that threaten the public health, safety, and welfare. Landscaping of single-family residences, existing permitted commercial forestry and mining activities in areas zoned for resource use, and development sites with approved and constructed drainage facilities that infiltrate 100 percent of surface runoff should be 6 exempt from these restrictions, although appropriate measures as identified in BW-8.2 above, should be taken to prevent off-site movement of sediment. When land clearing is permitted, disturbed soil areas that are to be left unworked for more than 12 hours should be covered with appropriate erosion control measures as required in the 1990 King County Surface Water Design Manual to prevent off-site erosion. The project will comply with the seasonal clearing, grading, and construction limitations as defined here and in the current codes. BW-10:Hillslope Development and Drainage Restrictions This BW recommendation pertains to the required buffers stormwater management for steep slopes and landslide hazard areas. The full description for this recommendation is available on page 3-15 of the Basin Plan. The project is not located on or near a steep slope; therefore, this BW recommendation is not applicable. BW-11:Wetland and Stream No Net Loss Policy This BW recommendation was copied from the Basin Plan (page 3-15) in its entirety for brevity. A basinwide policy of no overall net loss of wetland and stream functions and values, and a net gain over time, should be adopted by all jurisdictions in the basins. This policy would be consistent with directives from the federal and state governments. The City has no jurisdiction over wetland and stream impacts for this Project, therefore this BW recommendation is not directly applicable to the Project. However, no net loss of wetland and stream functions and values is being met for the Project consistent with the current US Army Corps of Engineers (USACE) regulatory requirements. BW-12:Order of Mitigation This BW recommendation was copied from the Basin Plan (page 3-15) in its entirety because it is applicable to the project site. Impacts to streams, wetlands, or lakes should be mitigated using the following descending order of preference: 1.Avoid the impact all together by not taking a certain action or parts of an action; 2.Minimize impact by limiting the degree or magnitude of the action and its implementation by using appropriate technology, or by taking affirmative steps to avoid or reduce impact; 3.Rectify the impact by repairing, rehabilitating or restoring the affected sensitive areas; 4.Reduce or eliminate the impact over time by prevention and maintenance operations during the life of the actions; 5.Compensate for the impact by replacing, enhancing, or providing substitute sensitive areas and environments; 7 6.Monitor the impact and take appropriate corrective measures. This BW recommendation is consistent with the standard mitigation sequencing required by the USACE that was followed for both the City permitting effort as well as through the USACE permitting process to address the wetland impacts. The BW recommendation is met as described in the Critical Areas Report and Buffer Averaging Plan by Talasaea Consultants, Inc., dated April 2020. BW-13:Resource Replacement and Enhancement Standards This BW recommendation was copied from the Basin Plan (pages 3-15 to 3-16) in its entirety because it is applicable to the project site. 1.If a wetland must be altered or enhanced, the formulae for best wetland mitigation should be as follows with equal or greater biologic values: Class 1 and 2 wetlands on a 2:1 type and acreage basis Class 3 wetlands on a 1:1 type and acreage basis Projects whose primary objective is to restore the functions and values of a previously damaged wetland to approximate its pre-developed functions and values should be exempt from this mitigation requirement. This exemption should only apply, however, if the restoration is not mitigation for offsite or adjacent development impacts. 2.For all stream classes, mitigation plans should be developed to replace and enhance stream elements such as pools, riffles, LOD, and spawning gravel on a relative 2:1 basis in function and area. This mitigation may be accomplished at the project site or on another stream reach through mitigation banking. No stream impacts are proposed for this Project. The City has no jurisdiction over wetland impacts for this Project, therefore this BW recommendation is not directly applicable to the Project. However, wetland impacts are being addressed by current USACE regulatory requirements using the King County In- Lieu Fee (ILF) Program. The purchase of mitigation credits through the ILF Program has been recognized as being consistent with the wetland replacement ratios, consistent with those outlined above for this BW recommendation. Therefore, this BW recommendation is met with details provided in the Critical Areas Report and Proposed Mitigation Plan by Talasaea Consultants, Inc., dated 9 April 2020 and the Addendum to the 9 April 2020 Critical Areas Report and Proposed Mitigation Plan by Wet.land, LLC., dated 10 October 2021. BW-14:Sensitive Area Mitigation Fund This BW recommendation was copied from the Basin Plan (page 3-16) in its entirety for brevity. A fund should be established solely for use in enforcing and implementing sensitive areas codes. All moneys obtained from civil penalties and sensitive area violations should be deposited in this fund. 8 This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-15:Sensitive Area Mapping This BW recommendation pertains to the establishment of a sensitive area map within the study area of the basin plan. The full description for this recommendation is available starting on page 3-16 of the Basin Plan. This BW recommendation is applicable to the City of Federal Way and not applicable to the project. 3.4 BASIN REVEGETATION BW-16:Basin Revegetation This BW recommendation pertains to the revegetation of priority areas, the supporting infrastructure to carry out the revegetation, and to coordinate all actions through the Stream Steward (BW-38). The full description for this recommendation is available on page 3-26 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. 3.5 MANAGEMENT OF NONPOINT SOURCE WATER POLLUTION BW-17:BMP Programs for Control of Nonpoint Source Pollutants This BW recommendation pertains to the required mitigation efforts to minimize pollution from nonpoint source pollutants. The full description for this recommendation is available on pages 3-32 to 3-34 of the Basin Plan. As described in the TIR, due to the proposed use of the project site, source control is not required and this BW recommendation is not applicable. The project will provide enhanced basic water quality treatment to reduce stormwater pollutants. BW-18:Highway Runoff Controls This BW recommendation pertains to the required flow rate mitigation for highways in the study area of the basin plan. The full description for this recommendation is available on page 3-34 of the Basin Plan. This BW recommendation is the responsibility of WSDOT and local entities; therefore, this BW recommendation not applicable. BW-19:Collection and Disposal of Residuals This BW recommendation pertains to the collection and disposal of residuals collected in the private and public stormwater system. The full description for this recommendation is available starting on page 3-34 of the Basin Plan. 9 This BW recommendation is the responsibility of the Public Works Department; therefore, this BW recommendation not applicable. BW-20:Maintenance of Roadside Ditches This BW recommendation pertains to the maintenance of roadside ditches with special instructions when within 1/4 mile of a Class 2 or 3 stream. The full description for this recommendation is available on page 3-35 of the basin plan. This BW recommendation is the responsibility of the Public Works Department; therefore, this BW recommendation not applicable. BW-21:Stormwater Infiltration Limitations This BW recommendation was copied from the Basin Plan (pages 3-35 to 3-36) in its entirety for brevity. Stormwater infiltration facilities should be used in rural and low- to moderate-density land- use areas wherever soil conditions are conducive to replenish groundwater and augment summer flows. New development should be required to determine the feasibility of infiltration and to provide such facilities to the extent possible. Infiltration facilities should not be used in high density areas with multifamily or commercial land uses (see also WHL- 4, Chapter 4.1). Infiltration was not considered feasible for this project by the geotechnical engineer; therefore, this BW recommendation is not applicable. BW-22:Lake Water Quality Management Programs This BW recommendation pertains to the suggested actions to be taken by lakeside residents. The full description for this recommendation is available starting on page 3-36 of the Basin Plan. This BW recommendation is the responsibility of lakeside residents; therefore, this BW recommendation not applicable. 3.6 PLAN MONITORING AND UPDATE BW-23:Database Management and Update This BW recommendation pertains to the basin-specific Database update and management procedures for the Stream Steward (BW-38). The full description for this recommendation is available on page 3-39 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-24:Flow and Development Monitoring 10 This BW recommendation pertains to the suggested flow and development monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available starting on page 3-39 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-25:Sediment Transport Monitoring This BW recommendation pertains to the suggested sediment monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-26:Regional Monitoring This BW recommendation pertains to the suggested regional monitoring to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the basin plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-27:Sampling Methods This BW recommendation pertains to the suggested sampling methods to be used throughout the basin and to be enforced by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-28:Short-Term Runoff Event Monitoring for Water Quality Constituents This BW recommendation pertains to sampling sites, to be used by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-40 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-29:Short-Term Highway Runoff Monitoring This BW recommendation was copied from the Basin Plan (page 3-43) in its entirety for brevity. WSDOT is developing a program to control the runoff from freeways and highways in the Puget Sound Basin (see BW-18). A sampling program should be developed that includes 11 storm event monitoring of highways before and after BMP implementation. Variables to be monitored should include metals, solids, phosphorus, oil/grease, and hydrocarbons. This BW recommendation is the responsibility of the Stream Steward (per BW-38) & WSDOT; therefore, this BW recommendation not applicable. BW-30:Short-Term Monitoring of Fecal Bacteria Source Areas This BW recommendation pertains to the suggested short-term monitoring of fecal bacteria source areas to be carried out by the Federal Way Water and Sewer District. The full description for this recommendation is available on page 3-43 of the basin plan. This BW recommendation is the responsibility of the Lakehaven Water and Sewer District; therefore, this BW recommendation not applicable. BW-31:Long-Term Monitoring for Water Quality Trends This BW recommendation pertains to the suggested long-term monitoring of water quality to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-43 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. BW-32:Annual Report and Plan Amendment This BW recommendation pertains to the suggested additional resources that should be made available to the Stream Steward (BW-38) by the citizens to carry out the basin plan. The full description for this recommendation is available starting on page 3-43 of the Basin Plan. The project owner is not part of the citizens’ committee; therefore, this BW recommendation is not applicable. 3.7 CODE COMPLIANCE BW-33:Enforcement/Inspection Staff This BW recommendation pertains to the suggested additional enforcement staff that should be made available to enforce the basin plan. The full description for this recommendation is available on page 3-45 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-34:Citations This BW recommendation was copied from the Basin Plan (page 3-45) in its entirety for brevity. 12 A system for issuing citations with civil penalties, analogous to traffic tickets but with greater penalties, should be established for violations of drainage and environmentally sensitive areas ordinances. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-35:Penalties This BW recommendation pertains to the suggested penalties for violations of code. The full description for this recommendation is available on page 3-46 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-36:Violation Reporting This BW recommendation pertains to the suggested violation reporting improvements. The full description for this recommendation is available on page 3-46 of the Basin Plan. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. 3.8 EDUCATION AND PUBLIC INVOLVEMENT BW-37:Education and Public Involvement This BW recommendation pertains to the suggested education and public involvement to be carried out by the Stream Steward (BW-38). The full description for this recommendation is available on page 3-47 of the Basin Plan. This BW recommendation is the responsibility of the Stream Steward (per BW-38); therefore, this BW recommendation not applicable. 3.9 STREAM STEWARD BW-38:Stream Steward This BW recommendation pertains to employing a Stream Steward. The full description for this recommendation is available on page 3-49 of the Basin Plan. The Stream Steward employment is not the responsibility of the project; therefore, this BW recommendation is not applicable. 3.10 TAX INCENTIVES BW-39:Current-Use Taxation This BW recommendation was copied from the Basin Plan (page 3-50) in its entirety for brevity. 13 Current use taxation programs should be expanded to include properties that contain stream and wetland buffers within RSRAs and LSRAs as identified in this Basin Plan. A rating system should be adopted by all jurisdictions in the basins to evaluate the public benefit of accepting these areas into the open space system in exchange for private tax concessions. This BW recommendation is the responsibility of the local jurisdictions and the Assessor; therefore, this BW recommendation not applicable. BW-40:State Assessment Procedures This BW recommendation was copied from the Basin Plan (page 3-50) in its entirety for brevity. The statutes governing appeals of property-tax assessments should be amended to allow simplified appeals where downzones or sensitive areas designations have affected potential development opportunities. The appeal results should apply without need for further property-owner action until the next regular valuation becomes effective. This BW recommendation is the responsibility of the local jurisdictions and the Assessor; therefore, this BW recommendation not applicable. BW-41:Conservation Easements and Land Trusts This BW recommendation was copied from the Basin Plan (page 3-50) in its entirety for brevity. Encourage private donations of conservation easements for streams, wetlands, and their buffers in RSRAs, LSRAs, and wildlife corridors to public and private caretaker agencies. Public caretaker agencies include the King County Parks Division and private conservation groups include the Trust for Public Lands. Similar programs can also be established in Des Moines, Federal Way, Kent, Milton, and Tacoma. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. 3.11 PROGRAM MANAGEMENT BW-42:Annexations and Incorporations This BW recommendation was copied from the Basin Plan (page 3-52) in its entirety for brevity. If annexations or incorporations remove areas of the basins from King County's jurisdiction, interlocal agreements should be drafted to ensure that city surface water management plans are consistent with, or more protective than, this Basin Plan. King County and other cooperators on this Basin Plan should oppose those proposed annexations that do not meet this standard. 14 This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. BW-43:King County SWM Division CIP Funding Policy This BW recommendation was copied from the Basin Plan (page 3-52) in its entirety for brevity. Implementation of the Basin Plan in King County will follow the recommended policy identified in the SWM Strategic Plan. All capital improvements projects in King County will be funded at a level to at least begin initial design work during the calendar year following Basin Plan adoption. This BW recommendation is the responsibility of the local jurisdictions; therefore, this BW recommendation not applicable. If you have any questions regarding the information presented in this adjustment request, please feel free to contact me at (253) 838-6113 or laura@esmcivil.com. \\esm8\engr\esm-jobs\1886\001\016-0016\stormreport\documents\memo-999 - basin wide rec.docx