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17-105489-Preliminary Technical Information Report-11-12-2021-V3Woodbridge Business Park Preliminary Technical Information Report November 12, 2021 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 11/10/2021 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 1. Project Overview The purpose of this report is to encapsulate the documents and analysis required by the Full Drainage Review in the 2016 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 4 parcels on approximately 146 acres (162104-9030,162104-9013,162104-9056, and 152104-9178) 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 a visual representation of 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 drains 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. 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 approximately 71.44 acres (70.59 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: As detailed in the pre-application meeting notes, 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. µ ΗΜΣ∆ Θ Ρ Σ ≅ Σ ∆ 4 ς∆ Ξ ∆ Θ Γ ≅ ∆ Τ Ρ ∆ Θ ς ≅ Ξ Ρ ς∆Ξ∆ΘΓ≅∆ΤΡ∆Θ ς ≅ Ξ Ρ Ρ 2 2 5 Σ Γ Ρ Σ Θ ∆ ∆ Σ DRAWING:JOB NO.DATE:DRAWN:SHEET OF(425) 297-9900(253) 838-6113www.esmcivil.comLand PlanningLandscape ArchitectureLand SurveyingProject ManagementPublic WorksCivil EngineeringΚ Κ ΒΕδχδθκ ςξ+ ς≅ 87//2223// 7σγ ≅υδ Ρ+ Ρτησδ 1/4Β Ν Μ Ρ Τ Κ Σ Η Μ Φ ∆ Μ Φ Η Μ ∆ ∆ Θ ΡFEDERAL WAYEVERETT\\\\esm8\\engr\\ESM-JOBS\\1886\\001\\016-0010\\exhibits\\EN-03.dwg1/3/2020 4:29 PMPlotted:File:Plotted By: Tony AblemanΕ∆Χ∆Θ≅Κ ς≅Ξ Β≅ΛΟΤΡ+ ΚΚΒςΝΝΧΑΘΗΧΦ∆ ΑΤΡΗΜ∆ΡΡ Ο≅ΘϑEXISTING CONDITIONS1886-001-016-0010EN-03JJH10/07/20161 1 ΡΒ≅Κ∆9 0! < 0 2//& 150 300 \pxqc;EXISTING BUILDING ΕΗΦΤΘ∆ 0−1 WETLAND FA WAS DETERMINED TO NOT BE A WETLAND IN CONJUNCTION WITH THE PLAN APPROVAL FOR THE DAVITA SITE.AAA AAA AAAAAAAAAAAAAAAAAAAAA AAAAAAAAA AAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAXFMRE002E002AAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA201200AAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAAAAAAAA AAAAAAAAA AAAAAAXFMRE002 E002 AAA AAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA AAA Ρ 2 2 5 Σ Γ Ρ Σ ς∆Ξ∆ΘΓ ≅ ∆ Τ Ρ ∆ Θ ς ≅ Ξ Ρ − µ ΡΒ≅Κ∆9 0! < 0 50 0//& 200100 NO.DESCRIPTION/DATE BY REVISIONS DWG. NAME DESIGNED BY: DRAWN BY: CHECKED BY: DATE: OF SHEETS JOB NO.\\\\esm8\\engr\\esm-jobs\\1886\\001\\016-0016\\exhibits\\EN-06.dwg11/10/2021 2:58 PMPlotted:File:Plotted By: Chad CurkendallEVERETTFEDERAL WAYΒ Ν Μ Ρ Τ Κ Σ Η Μ Φ ∆ Μ Φ Η Μ ∆ ∆ Θ ΡΚ Κ ΒCivil EngineeringProject ManagementLand SurveyingLandscape ArchitectureLand Planningwww.esmcivil.com(253) 838-6113(425) 297-9900Public WorksΕδχδθκ ςξ+ ς≅ 87//2223// 7σγ ≅υδ Ρ+ Ρτησδ 1/4Ε∆Χ∆Θ≅Κ ς≅Ξ Β≅ΛΟΤΡ+ ΚΚΒςΝΝΧΑΘΗΧΦ∆ ΑΤΡΗΜ∆ΡΡ Ο≅ΘϑPROPOSED SITE CONDITIONSWASHINGTONCITY OF FEDERAL WAY1886-001-016 EN-06 LGB JJH 03/18/2020 ΕΗΦ 0−2 0 0 ΗΜΣ∆ Θ Ρ Σ ≅ Σ ∆ 4 ΟΝΜΧ 1 Χ∆Σ∆ΜΣΗΝΜ Υ≅ΤΚΣ 0 Χ∆Σ∆ΜΣΗΝΜ ΟΝΜΧ 2 Χ∆Σ∆ΜΣΗΝΜ ΟΝΜΧ 3 Χ∆Σ∆ΜΣΗΝΜ ΟΝΜΧ 4 Χ∆Σ∆ΜΣΗΝΜ Κ∆Φ∆ΜΧ STORM DRAINAGE SANITARY SEWER WATER FIRE HYDRANT CATCH BASIN ROOF DRAIN LINE SANITARY SEWER MANHOLE ΑΤΗΚΧΗΜΦ !0! °5/5+/// ΡΕ ΕΕ<Υ≅ΘΗ∆Ρ 331−26,337−76 ΑΤΗΚΧΗΜΦ !1! °13/+8// ΡΕ ΕΕ<Υ≅ΘΗ∆Ρ 31/−//,313−64 ΕΤΣΤΘ∆ ΑΤΗΚΧΗΜΦ !2! °014+6// ΡΕ ΕΕ<Υ≅ΘΗ∆Ρ 311−//,313−4 ∆ΩΗΡΣΗΜΦ ςΣΒ ΑΤΗΚΧΗΜΦ ΕΕ<326−// 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). However, it is not part of the existing or developed drainage basin, and no associated drainage problems are known. 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 11.30 + 0.52 22.24 + 0.36 16.10 6.27 13.05 + 0.75 Developed Site Hydrology: The developed Basins 1-5 (totaling 70.59 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 11.30 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. 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 22.24 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, including the areas nearest to the sphagnum bog adjacent to the northwest corner of the project site. 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 13.05 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 1.53 0.24 6.03 Road 5.60 0.00 10.02 0.33 5.91 3.89 5.06 0.51 31.32 Roof 4.89 0.00 9.02 0.00 7.13 1.25 5.53 0.00 27.82 Basin Total 11.30 0.52 22.24 0.36 16.10 6.27 13.05 0.75 70.59 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 31.32 acres of road area, 27.82 acres of roof area, and 4.77 acres of impervious frontage area (3.07 ac asphalt pavement + 1.7 ac sidewalk), which totals 63.91 acres of impervious area. With 10.84 acres of replaced impervious area and 7.75 acres of existing impervious area to remain removed from the total impervious area, 45.32 acres of new impervious area is proposed, which 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 2016 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 2016 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 0.348 0.228 0.664 0.474 0.473 0.260 0.184 0.094 0.406 1.065 5 Year 0.545 0.337 1.044 0.693 0.743 0.358 0.290 0.136 0.637 1.873 10 Year 0.658 0.420 1.258 0.863 0.896 0.434 0.349 0.169 0.768 2.532 25 Year 0.777 0.538 1.486 1.108 1.059 0.543 0.412 0.219 0.907 3.508 50 Year 0.851 0.637 1.627 1.314 1.159 0.634 0.451 0.262 0.993 4.342 100 Year 0.914 0.744 1.747 1.541 1.244 0.734 0.485 0.310 1.067 5.270 * 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 5.40* Provided 5.55 9.32 7.08 2.82 1.72 Additional Safety Factor 3%1%3%5%N/A *3.68 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 3.68 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 0.42-feet over the riser. Refer to Section 5 of this report for more information on Pond 5 flow computations. The Weyerhaeuser Pond’s headworks 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 160,300 cubic feet (3.68 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 0.46-feet (5.5 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 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 0.228 0.474 0.260 0.094 0.457* 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 3.68 acre-feet to the Weyerhaeuser Pond. Water quality for the asphalt pavement portion of the proposed frontage improvements will be provided in relocated roadside swales, matching the drainage flow paths for the existing pavement. 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. 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 (146 acres), the undisturbed native vegetation area of 56.9 acres mitigates for 16.26 acres of impervious area, which is equivalent to 23% of the total project site area (70.59 acres) and 27% of the total impervious area (59.14 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 0.744 cfs, which is less than the 100-year forested condition flow rate of 0.914 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 (1.541 + 0.734 + 0.310) 2.585 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 3.68 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 5.270 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 0.42 feet, refer to the chart in this section of the report for more information. The total stormwater runoff to this location is 10.417 cfs (2.585 + 1.581 + 5.270), 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 Critical Areas Report and Proposed Mitigation Plan by Talasaea Consultants, Inc., dated 9 April 2020 is included under separate cover. The Addendum to 9 April 2020 Critical Areas Report and Proposed Mitigation Plan by Wet.land, LLC., dated 10 October 2021 is 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 336TH STWEYERHAEUSER WAY S.nSCALE: 1" = 100'C O N S U L T I N G E N G I N E E R SL L C Federal Way, WA 98003 33400 8th Ave S, Suite 205FEDERAL WAY CAMPUS, LLC WOODBRIDGE BUSINESS PARK11INTERSTATE 5BUILDING "1"±606,000 SFFF=VARIES442.37-448.87BUILDING "2"±240,900 SFFF=VARIES420.00-424.75FUTUREBUILDING "3"±125,700 SFFF=VARIES422.00-424.5EXISTINGWTCBUILDINGFF=437.00APPROX.4.7 ACAPPROX.4.7 AC 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 11/10/2021 9:33:42 AM Page 2 General Model Information Project Name:BP Model A Site Name:Business Park Site Address:Model A - Vault 1 City: Report Date:11/10/2021 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year BP Model A 11/10/2021 9:33:42 AM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 11.3 Pervious Total 11.3 Impervious Land Use acre Impervious Total 0 Basin Total 11.3 Element Flows To: Surface Interflow Groundwater BP Model A 11/10/2021 9:33:42 AM 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 11/10/2021 9:33:42 AM 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 11/10/2021 9:33:42 AM 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 5.6 Impervious Total 5.6 Basin Total 6.41 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 BP Model A 11/10/2021 9:33:42 AM 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 11/10/2021 9:33:42 AM 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:1.84 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 0.029 0.000 0.2000 0.826 0.165 0.041 0.000 0.3000 0.826 0.247 0.050 0.000 0.4000 0.826 0.330 0.058 0.000 0.5000 0.826 0.413 0.065 0.000 0.6000 0.826 0.495 0.071 0.000 0.7000 0.826 0.578 0.076 0.000 0.8000 0.826 0.661 0.082 0.000 0.9000 0.826 0.743 0.087 0.000 1.0000 0.826 0.826 0.091 0.000 1.1000 0.826 0.909 0.096 0.000 1.2000 0.826 0.991 0.100 0.000 1.3000 0.826 1.074 0.104 0.000 1.4000 0.826 1.157 0.108 0.000 1.5000 0.826 1.239 0.112 0.000 1.6000 0.826 1.322 0.116 0.000 1.7000 0.826 1.405 0.119 0.000 1.8000 0.826 1.487 0.123 0.000 1.9000 0.826 1.570 0.126 0.000 2.0000 0.826 1.652 0.129 0.000 2.1000 0.826 1.735 0.133 0.000 2.2000 0.826 1.818 0.136 0.000 2.3000 0.826 1.900 0.139 0.000 2.4000 0.826 1.983 0.142 0.000 2.5000 0.826 2.066 0.145 0.000 2.6000 0.826 2.148 0.148 0.000 2.7000 0.826 2.231 0.151 0.000 2.8000 0.826 2.314 0.153 0.000 2.9000 0.826 2.396 0.156 0.000 3.0000 0.826 2.479 0.159 0.000 3.1000 0.826 2.562 0.161 0.000 3.2000 0.826 2.644 0.164 0.000 3.3000 0.826 2.727 0.166 0.000 3.4000 0.826 2.809 0.187 0.000 BP Model A 11/10/2021 9:33:42 AM Page 10 3.5000 0.826 2.892 0.198 0.000 3.6000 0.826 2.975 0.206 0.000 3.7000 0.826 3.057 0.236 0.000 3.8000 0.826 3.140 0.252 0.000 3.9000 0.826 3.223 0.266 0.000 4.0000 0.826 3.305 0.278 0.000 4.1000 0.826 3.388 0.289 0.000 4.2000 0.826 3.471 0.299 0.000 4.3000 0.826 3.553 0.311 0.000 4.4000 0.826 3.636 0.324 0.000 4.5000 0.826 3.719 0.337 0.000 4.6000 0.826 3.801 0.351 0.000 4.7000 0.826 3.884 0.365 0.000 4.8000 0.826 3.966 0.379 0.000 4.9000 0.826 4.049 0.394 0.000 5.0000 0.826 4.132 0.408 0.000 5.1000 0.826 4.214 0.422 0.000 5.2000 0.826 4.297 0.436 0.000 5.3000 0.826 4.380 0.451 0.000 5.4000 0.826 4.462 0.467 0.000 5.5000 0.826 4.545 0.483 0.000 5.6000 0.826 4.628 0.499 0.000 5.7000 0.826 4.710 0.548 0.000 5.8000 0.826 4.793 0.568 0.000 5.9000 0.826 4.876 0.588 0.000 6.0000 0.826 4.958 0.608 0.000 6.1000 0.826 5.041 0.629 0.000 6.2000 0.826 5.124 0.651 0.000 6.3000 0.826 5.206 0.672 0.000 6.4000 0.826 5.289 0.694 0.000 6.5000 0.826 5.371 0.716 0.000 6.6000 0.826 5.454 1.223 0.000 6.7000 0.826 5.537 2.131 0.000 6.8000 0.826 5.619 3.233 0.000 6.9000 0.826 5.702 4.370 0.000 7.0000 0.826 5.785 5.382 0.000 7.1000 0.826 5.867 6.149 0.000 7.2000 0.826 5.950 6.645 0.000 7.3000 0.826 6.033 7.096 0.000 7.4000 0.826 6.115 7.486 0.000 7.5000 0.826 6.198 7.855 0.000 7.6000 0.826 6.281 8.205 0.000 7.7000 0.826 6.363 8.541 0.000 7.8000 0.826 6.446 8.862 0.000 7.9000 0.826 6.528 9.172 0.000 8.0000 0.826 6.611 9.471 0.000 8.1000 0.826 6.694 9.761 0.000 8.2000 0.826 6.776 10.04 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 11.81 0.000 9.0000 0.826 7.438 12.04 0.000 9.1000 0.826 7.520 12.26 0.000 9.2000 0.000 0.000 12.49 0.000 BP Model A 11/10/2021 9:33:42 AM Page 12 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:11.82 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.33 Total Impervious Area:10.49 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.347518 5 year 0.54579 10 year 0.658155 25 year 0.777195 50 year 0.850857 100 year 0.91351 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.228497 5 year 0.337009 10 year 0.420026 25 year 0.538296 50 year 0.636554 100 year 0.743896 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.341 0.194 1950 0.426 0.225 1951 0.765 0.510 1952 0.241 0.141 1953 0.195 0.210 1954 0.300 0.173 1955 0.478 0.175 1956 0.380 0.335 1957 0.307 0.176 1958 0.346 0.189 BP Model A 11/10/2021 9:34:11 AM Page 13 1959 0.296 0.167 1960 0.517 0.409 1961 0.292 0.276 1962 0.182 0.141 1963 0.249 0.178 1964 0.328 0.268 1965 0.235 0.301 1966 0.226 0.171 1967 0.473 0.248 1968 0.295 0.173 1969 0.288 0.165 1970 0.238 0.189 1971 0.254 0.198 1972 0.570 0.413 1973 0.259 0.298 1974 0.281 0.175 1975 0.381 0.187 1976 0.275 0.176 1977 0.033 0.147 1978 0.241 0.215 1979 0.146 0.133 1980 0.540 0.432 1981 0.216 0.172 1982 0.415 0.398 1983 0.372 0.177 1984 0.230 0.149 1985 0.136 0.152 1986 0.602 0.263 1987 0.533 0.390 1988 0.210 0.164 1989 0.137 0.152 1990 1.114 0.428 1991 0.671 0.428 1992 0.259 0.205 1993 0.269 0.148 1994 0.091 0.129 1995 0.386 0.288 1996 0.814 0.481 1997 0.681 0.492 1998 0.154 0.165 1999 0.638 0.429 2000 0.269 0.228 2001 0.048 0.119 2002 0.294 0.291 2003 0.376 0.171 2004 0.486 0.528 2005 0.349 0.170 2006 0.411 0.330 2007 0.827 0.671 2008 1.067 0.460 2009 0.524 0.319 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 1.1140 0.6710 2 1.0667 0.5280 3 0.8269 0.5099 BP Model A 11/10/2021 9:34:11 AM Page 14 4 0.8143 0.4920 5 0.7653 0.4812 6 0.6807 0.4602 7 0.6708 0.4319 8 0.6383 0.4295 9 0.6023 0.4280 10 0.5699 0.4276 11 0.5401 0.4130 12 0.5328 0.4087 13 0.5237 0.3977 14 0.5174 0.3899 15 0.4864 0.3354 16 0.4776 0.3303 17 0.4725 0.3190 18 0.4257 0.3013 19 0.4151 0.2978 20 0.4115 0.2907 21 0.3864 0.2878 22 0.3807 0.2759 23 0.3800 0.2678 24 0.3756 0.2633 25 0.3722 0.2481 26 0.3489 0.2285 27 0.3455 0.2249 28 0.3414 0.2150 29 0.3283 0.2097 30 0.3067 0.2052 31 0.2995 0.1982 32 0.2964 0.1940 33 0.2948 0.1890 34 0.2944 0.1886 35 0.2919 0.1869 36 0.2884 0.1782 37 0.2810 0.1766 38 0.2752 0.1763 39 0.2694 0.1756 40 0.2687 0.1748 41 0.2589 0.1746 42 0.2587 0.1729 43 0.2543 0.1726 44 0.2494 0.1725 45 0.2415 0.1715 46 0.2412 0.1715 47 0.2378 0.1700 48 0.2350 0.1667 49 0.2297 0.1653 50 0.2260 0.1648 51 0.2159 0.1635 52 0.2102 0.1517 53 0.1950 0.1515 54 0.1816 0.1487 55 0.1540 0.1476 56 0.1459 0.1474 57 0.1372 0.1407 58 0.1363 0.1407 59 0.0905 0.1334 60 0.0482 0.1287 61 0.0328 0.1188 BP Model A 11/10/2021 9:34:11 AM Page 16 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.1738 17731 17714 99 Pass 0.1806 16277 14555 89 Pass 0.1874 15032 13265 88 Pass 0.1943 13890 12314 88 Pass 0.2011 12827 11056 86 Pass 0.2080 11946 10016 83 Pass 0.2148 10998 8846 80 Pass 0.2216 10173 8269 81 Pass 0.2285 9426 7899 83 Pass 0.2353 8757 7578 86 Pass 0.2422 8162 7306 89 Pass 0.2490 7670 6973 90 Pass 0.2558 7118 6554 92 Pass 0.2627 6622 6136 92 Pass 0.2695 6175 5704 92 Pass 0.2763 5790 5274 91 Pass 0.2832 5437 4785 88 Pass 0.2900 5097 4318 84 Pass 0.2969 4840 4032 83 Pass 0.3037 4549 3713 81 Pass 0.3105 4269 3465 81 Pass 0.3174 4030 3187 79 Pass 0.3242 3792 2920 77 Pass 0.3311 3548 2656 74 Pass 0.3379 3362 2481 73 Pass 0.3447 3155 2319 73 Pass 0.3516 2962 2135 72 Pass 0.3584 2791 1969 70 Pass 0.3653 2603 1813 69 Pass 0.3721 2449 1626 66 Pass 0.3789 2325 1520 65 Pass 0.3858 2175 1379 63 Pass 0.3926 2041 1231 60 Pass 0.3995 1910 1120 58 Pass 0.4063 1791 984 54 Pass 0.4131 1689 867 51 Pass 0.4200 1605 782 48 Pass 0.4268 1493 687 46 Pass 0.4337 1387 563 40 Pass 0.4405 1296 505 38 Pass 0.4473 1225 437 35 Pass 0.4542 1155 381 32 Pass 0.4610 1098 345 31 Pass 0.4679 1055 323 30 Pass 0.4747 1000 293 29 Pass 0.4815 930 258 27 Pass 0.4884 884 231 26 Pass 0.4952 838 208 24 Pass 0.5020 789 188 23 Pass 0.5089 746 168 22 Pass 0.5157 719 147 20 Pass 0.5226 673 132 19 Pass 0.5294 634 117 18 Pass BP Model A 11/10/2021 9:34:11 AM Page 17 0.5362 596 116 19 Pass 0.5431 566 114 20 Pass 0.5499 541 113 20 Pass 0.5568 501 111 22 Pass 0.5636 475 110 23 Pass 0.5704 437 109 24 Pass 0.5773 401 105 26 Pass 0.5841 367 101 27 Pass 0.5910 351 89 25 Pass 0.5978 326 80 24 Pass 0.6046 298 65 21 Pass 0.6115 275 60 21 Pass 0.6183 256 55 21 Pass 0.6252 235 50 21 Pass 0.6320 218 45 20 Pass 0.6388 201 41 20 Pass 0.6457 182 37 20 Pass 0.6525 158 33 20 Pass 0.6594 145 28 19 Pass 0.6662 129 12 9 Pass 0.6730 119 0 0 Pass 0.6799 110 0 0 Pass 0.6867 97 0 0 Pass 0.6936 91 0 0 Pass 0.7004 82 0 0 Pass 0.7072 76 0 0 Pass 0.7141 69 0 0 Pass 0.7209 62 0 0 Pass 0.7277 55 0 0 Pass 0.7346 48 0 0 Pass 0.7414 41 0 0 Pass 0.7483 38 0 0 Pass 0.7551 33 0 0 Pass 0.7619 28 0 0 Pass 0.7688 23 0 0 Pass 0.7756 21 0 0 Pass 0.7825 20 0 0 Pass 0.7893 19 0 0 Pass 0.7961 17 0 0 Pass 0.8030 14 0 0 Pass 0.8098 12 0 0 Pass 0.8167 9 0 0 Pass 0.8235 4 0 0 Pass 0.8303 3 0 0 Pass 0.8372 3 0 0 Pass 0.8440 3 0 0 Pass 0.8509 3 0 0 Pass BP Model A 11/10/2021 9:34:11 AM 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 11/10/2021 9:34:11 AM Page 19 LID Report BP Model A 11/10/2021 9:34:53 AM Page 22 Appendix Predeveloped Schematic BP Model A 11/10/2021 9:34:53 AM Page 23 Mitigated Schematic BP Model A 11/10/2021 9:34:54 AM 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. 2005-2021; 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 6/18/2021 11:40:24 AM Page 2 General Model Information Project Name:BP Model B Site Name:Business Park Site Address:Model B - Ponds 2 through 5 City: Report Date:6/18/2021 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 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 6/18/2021 11:40:24 AM Page 3 Landuse Basin Data Predeveloped Land Use PreDev - Basin 5 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.12 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 4 Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.93 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 5 PreDev - Basin 5 - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.75 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 6 Pond 4 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.76 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 7 PreDev - Basin 4 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 5.51 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 8 PreDev - Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 14.46 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 9 Pond 3 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.64 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 10 PreDev - Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 20.15 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 11 Pond 2 Area Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 2.09 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 12 PreDev - Basin 2 - Bypass Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.36 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 13 PreDev - Basin 5 - WQ Node Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.53 Pervious Total 0 Impervious Land Use acre ROADS FLAT 5.06 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater BP Model B 6/18/2021 11:40:24 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 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model B 6/18/2021 11:40:24 AM Page 15 Dev - Basin 5 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.24 Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.51 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 16 Pond 5 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.93 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model B 6/18/2021 11:40:24 AM Page 17 Pond 4 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.76 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 4 - 2.7:1 SS Pond 4 - 2.7:1 SS BP Model B 6/18/2021 11:40:24 AM Page 18 Dev - Basin 4 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.37 Pervious Total 0 Impervious Land Use acre ROADS FLAT 3.89 ROOF TOPS FLAT 1.25 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 4 - 2.7:1 SS Pond 4 - 2.7:1 SS BP Model B 6/18/2021 11:40:24 AM Page 19 Dev - Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.42 Pervious Total 0 Impervious Land Use acre ROADS FLAT 5.91 ROOF TOPS FLAT 7.13 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 3 - 2:1 SS Pond 3 - 2:1 SS BP Model B 6/18/2021 11:40:24 AM Page 20 Pond 3 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.64 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 3 - 2:1 SS Pond 3 - 2:1 SS BP Model B 6/18/2021 11:40:24 AM Page 21 Dev - Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.11 Pervious Total 0 Impervious Land Use acre ROADS FLAT 10.02 ROOF TOPS FLAT 9.02 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 2 - 2:1 SS Pond 2 - 2:1 SS BP Model B 6/18/2021 11:40:24 AM Page 22 Pond 2 Area Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.09 Pervious Total 0 Impervious Land Use acre Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 2 - 2:1 SS Pond 2 - 2:1 SS BP Model B 6/18/2021 11:40:24 AM Page 23 Dev - Basin 2 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.03 Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.33 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Business Park POC Business Park POC BP Model B 6/18/2021 11:40:24 AM Page 24 Dev - Basin 5 - PGIS Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.53 Pervious Total 0 Impervious Land Use acre ROADS FLAT 5.06 Impervious Total 0 Basin Total 0 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model B 6/18/2021 11:40:24 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 6/18/2021 11:40:24 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 6/18/2021 11:40:24 AM Page 27 Mitigated Routing Pond 2 - 2:1 SS Bottom Length:370.00 ft. Bottom Width:146.00 ft. Depth:9 ft. Volume at riser head:9.2521 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:2.52 in.Elevation:0 ft. Orifice 2 Diameter:2.25 in.Elevation:3.6 ft. Orifice 3 Diameter:2.5 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 1.240 0.000 0.000 0.000 0.1000 1.244 0.124 0.054 0.000 0.2000 1.249 0.249 0.077 0.000 0.3000 1.254 0.374 0.094 0.000 0.4000 1.259 0.499 0.109 0.000 0.5000 1.263 0.626 0.121 0.000 0.6000 1.268 0.752 0.133 0.000 0.7000 1.273 0.879 0.144 0.000 0.8000 1.278 1.007 0.154 0.000 0.9000 1.283 1.135 0.163 0.000 1.0000 1.287 1.263 0.172 0.000 1.1000 1.292 1.393 0.180 0.000 1.2000 1.297 1.522 0.188 0.000 1.3000 1.302 1.652 0.196 0.000 1.4000 1.307 1.783 0.203 0.000 1.5000 1.312 1.913 0.211 0.000 1.6000 1.316 2.045 0.218 0.000 1.7000 1.321 2.177 0.224 0.000 1.8000 1.326 2.309 0.231 0.000 1.9000 1.331 2.442 0.237 0.000 2.0000 1.336 2.576 0.243 0.000 2.1000 1.341 2.709 0.249 0.000 2.2000 1.346 2.844 0.255 0.000 2.3000 1.351 2.979 0.261 0.000 2.4000 1.356 3.114 0.267 0.000 2.5000 1.360 3.250 0.272 0.000 2.6000 1.365 3.386 0.277 0.000 2.7000 1.370 3.523 0.283 0.000 2.8000 1.375 3.660 0.288 0.000 2.9000 1.380 3.798 0.293 0.000 BP Model B 6/18/2021 11:40:24 AM Page 28 3.0000 1.385 3.936 0.298 0.000 3.1000 1.390 4.075 0.303 0.000 3.2000 1.395 4.215 0.308 0.000 3.3000 1.400 4.354 0.313 0.000 3.4000 1.405 4.495 0.317 0.000 3.5000 1.410 4.635 0.322 0.000 3.6000 1.415 4.777 0.327 0.000 3.7000 1.420 4.919 0.374 0.000 3.8000 1.425 5.061 0.397 0.000 3.9000 1.430 5.204 0.415 0.000 4.0000 1.435 5.347 0.431 0.000 4.1000 1.440 5.491 0.499 0.000 4.2000 1.445 5.635 0.535 0.000 4.3000 1.450 5.780 0.565 0.000 4.4000 1.455 5.925 0.591 0.000 4.5000 1.460 6.071 0.615 0.000 4.6000 1.465 6.217 0.638 0.000 4.7000 1.470 6.364 0.659 0.000 4.8000 1.476 6.512 0.686 0.000 4.9000 1.481 6.659 0.716 0.000 5.0000 1.486 6.808 0.749 0.000 5.1000 1.491 6.957 0.783 0.000 5.2000 1.496 7.106 0.818 0.000 5.3000 1.501 7.256 0.853 0.000 5.4000 1.506 7.406 0.889 0.000 5.5000 1.511 7.557 0.925 0.000 5.6000 1.517 7.709 0.961 0.000 5.7000 1.522 7.861 0.996 0.000 5.8000 1.527 8.013 1.036 0.000 5.9000 1.532 8.166 1.077 0.000 6.0000 1.537 8.320 1.119 0.000 6.1000 1.542 8.474 1.162 0.000 6.2000 1.548 8.628 1.302 0.000 6.3000 1.553 8.783 1.356 0.000 6.4000 1.558 8.939 1.411 0.000 6.5000 1.563 9.095 1.468 0.000 6.6000 1.568 9.252 1.982 0.000 6.7000 1.574 9.409 2.897 0.000 6.8000 1.579 9.566 4.006 0.000 6.9000 1.584 9.725 5.149 0.000 7.0000 1.589 9.883 6.168 0.000 7.1000 1.595 10.04 6.942 0.000 7.2000 1.600 10.20 7.445 0.000 7.3000 1.605 10.36 7.903 0.000 7.4000 1.610 10.52 8.298 0.000 7.5000 1.616 10.68 8.673 0.000 7.6000 1.621 10.84 9.030 0.000 7.7000 1.626 11.01 9.372 0.000 7.8000 1.632 11.17 9.700 0.000 7.9000 1.637 11.33 10.01 0.000 8.0000 1.642 11.50 10.32 0.000 8.1000 1.648 11.66 10.61 0.000 8.2000 1.653 11.83 10.90 0.000 8.3000 1.658 11.99 11.18 0.000 8.4000 1.664 12.16 11.45 0.000 8.5000 1.669 12.32 11.71 0.000 8.6000 1.674 12.49 11.97 0.000 8.7000 1.680 12.66 12.22 0.000 BP Model B 6/18/2021 11:40:24 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:2.06 in.Elevation:0 ft. Orifice 2 Diameter:1.19 in.Elevation:4.2 ft. Orifice 3 Diameter:1.94 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 6/18/2021 11:40:24 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 6/18/2021 11:40:24 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:1.27 in.Elevation:0 ft. Orifice 2 Diameter:1.07 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 6/18/2021 11:40:24 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 6/18/2021 11:40:24 AM Page 36 Pond 5 - 4:1 SS Bottom Length:200.00 ft. Bottom Width:300.00 ft. Depth:4.5 ft. Volume at riser head:5.4044 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:2.125 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 1.377 0.000 0.000 0.000 0.0500 1.382 0.069 0.027 0.000 0.1000 1.386 0.138 0.038 0.000 0.1500 1.391 0.207 0.047 0.000 0.2000 1.395 0.277 0.054 0.000 0.2500 1.400 0.347 0.061 0.000 0.3000 1.405 0.417 0.067 0.000 0.3500 1.409 0.487 0.072 0.000 0.4000 1.414 0.558 0.077 0.000 0.4500 1.419 0.629 0.082 0.000 0.5000 1.423 0.700 0.086 0.000 0.5500 1.428 0.771 0.090 0.000 0.6000 1.433 0.843 0.094 0.000 0.6500 1.437 0.914 0.098 0.000 0.7000 1.442 0.986 0.102 0.000 0.7500 1.447 1.059 0.106 0.000 0.8000 1.451 1.131 0.109 0.000 0.8500 1.456 1.204 0.113 0.000 0.9000 1.461 1.277 0.116 0.000 0.9500 1.466 1.350 0.119 0.000 1.0000 1.470 1.423 0.122 0.000 1.0500 1.475 1.497 0.125 0.000 1.1000 1.480 1.571 0.128 0.000 1.1500 1.485 1.645 0.131 0.000 1.2000 1.489 1.719 0.134 0.000 1.2500 1.494 1.794 0.137 0.000 1.3000 1.499 1.869 0.139 0.000 1.3500 1.504 1.944 0.142 0.000 1.4000 1.508 2.019 0.145 0.000 1.4500 1.513 2.095 0.147 0.000 1.5000 1.518 2.171 0.150 0.000 1.5500 1.523 2.247 0.152 0.000 BP Model B 6/18/2021 11:40:24 AM Page 37 1.6000 1.528 2.323 0.155 0.000 1.6500 1.532 2.399 0.157 0.000 1.7000 1.537 2.476 0.159 0.000 1.7500 1.542 2.553 0.162 0.000 1.8000 1.547 2.631 0.164 0.000 1.8500 1.552 2.708 0.166 0.000 1.9000 1.557 2.786 0.168 0.000 1.9500 1.562 2.864 0.171 0.000 2.0000 1.566 2.942 0.173 0.000 2.0500 1.571 3.020 0.175 0.000 2.1000 1.576 3.099 0.177 0.000 2.1500 1.581 3.178 0.201 0.000 2.2000 1.586 3.257 0.211 0.000 2.2500 1.591 3.337 0.256 0.000 2.3000 1.596 3.416 0.279 0.000 2.3500 1.601 3.496 0.302 0.000 2.4000 1.606 3.577 0.325 0.000 2.4500 1.611 3.657 0.348 0.000 2.5000 1.616 3.738 0.372 0.000 2.5500 1.621 3.819 0.396 0.000 2.6000 1.626 3.900 0.420 0.000 2.6500 1.631 3.981 0.445 0.000 2.7000 1.636 4.063 0.470 0.000 2.7500 1.641 4.145 0.495 0.000 2.8000 1.646 4.227 0.520 0.000 2.8500 1.651 4.309 0.545 0.000 2.9000 1.656 4.392 0.570 0.000 2.9500 1.661 4.475 0.596 0.000 3.0000 1.666 4.558 0.621 0.000 3.0500 1.671 4.642 0.647 0.000 3.1000 1.676 4.725 0.672 0.000 3.1500 1.681 4.809 0.698 0.000 3.2000 1.686 4.893 0.723 0.000 3.2500 1.691 4.978 0.748 0.000 3.3000 1.696 5.063 0.773 0.000 3.3500 1.701 5.148 0.802 0.000 3.4000 1.706 5.233 0.831 0.000 3.4500 1.711 5.318 0.860 0.000 3.5000 1.716 5.404 0.890 0.000 3.5500 1.721 5.490 1.075 0.000 3.6000 1.727 5.576 1.407 0.000 3.6500 1.732 5.663 1.830 0.000 3.7000 1.737 5.749 2.323 0.000 3.7500 1.742 5.836 2.863 0.000 3.8000 1.747 5.924 3.433 0.000 3.8500 1.752 6.011 4.011 0.000 3.9000 1.757 6.099 4.577 0.000 3.9500 1.763 6.187 5.111 0.000 4.0000 1.768 6.275 5.596 0.000 4.0500 1.773 6.364 6.019 0.000 4.1000 1.778 6.452 6.371 0.000 4.1500 1.783 6.542 6.653 0.000 4.2000 1.789 6.631 6.874 0.000 4.2500 1.794 6.720 7.059 0.000 4.3000 1.799 6.810 7.332 0.000 4.3500 1.804 6.900 7.533 0.000 4.4000 1.809 6.991 7.728 0.000 4.4500 1.815 7.081 7.918 0.000 BP Model B 6/18/2021 11:40:24 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 6/18/2021 11:40:24 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 6/18/2021 11:40:24 AM Page 41 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:58.77 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:10.12 Total Impervious Area:48.65 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 1.727887 5 year 2.713714 10 year 3.2724 25 year 3.864278 50 year 4.230535 100 year 4.542053 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.147342 5 year 1.642024 10 year 2.027661 25 year 2.586539 50 year 3.058568 100 year 3.581547 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 1.697 0.966 1950 2.116 1.118 1951 3.805 2.541 1952 1.199 0.768 1953 0.970 1.028 1954 1.489 0.853 1955 2.375 0.944 1956 1.890 1.607 1957 1.525 0.979 1958 1.718 0.941 BP Model B 6/18/2021 11:40:54 AM Page 42 1959 1.474 0.898 1960 2.573 1.923 1961 1.451 1.365 1962 0.903 0.733 1963 1.240 0.940 1964 1.632 1.232 1965 1.169 1.432 1966 1.124 0.936 1967 2.349 1.065 1968 1.466 0.918 1969 1.434 0.898 1970 1.182 0.915 1971 1.265 1.035 1972 2.834 2.049 1973 1.287 1.391 1974 1.397 0.928 1975 1.893 1.013 1976 1.368 0.874 1977 0.163 0.880 1978 1.201 1.082 1979 0.726 0.739 1980 2.685 2.193 1981 1.073 0.913 1982 2.064 1.906 1983 1.851 0.900 1984 1.142 0.808 1985 0.678 0.840 1986 2.995 1.163 1987 2.649 1.774 1988 1.045 0.904 1989 0.682 0.826 1990 5.539 1.972 1991 3.335 2.019 1992 1.286 1.026 1993 1.340 0.741 1994 0.450 0.714 1995 1.921 1.298 1996 4.049 2.395 1997 3.384 2.743 1998 0.766 0.904 1999 3.174 2.061 2000 1.336 1.027 2001 0.240 0.860 2002 1.464 1.267 2003 1.868 0.899 2004 2.418 2.499 2005 1.735 0.912 2006 2.046 1.596 2007 4.111 3.625 2008 5.304 2.189 2009 2.604 1.450 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 5.5388 3.6252 2 5.3035 2.7433 3 4.1113 2.5411 BP Model B 6/18/2021 11:40:54 AM Page 43 4 4.0487 2.4990 5 3.8049 2.3949 6 3.3845 2.1934 7 3.3350 2.1891 8 3.1738 2.0612 9 2.9949 2.0490 10 2.8335 2.0186 11 2.6853 1.9723 12 2.6491 1.9235 13 2.6040 1.9062 14 2.5728 1.7739 15 2.4182 1.6066 16 2.3746 1.5964 17 2.3495 1.4502 18 2.1164 1.4316 19 2.0641 1.3907 20 2.0458 1.3649 21 1.9211 1.2981 22 1.8929 1.2674 23 1.8896 1.2323 24 1.8677 1.1634 25 1.8506 1.1181 26 1.7348 1.0818 27 1.7179 1.0652 28 1.6973 1.0346 29 1.6321 1.0278 30 1.5248 1.0271 31 1.4892 1.0265 32 1.4736 1.0127 33 1.4656 0.9795 34 1.4640 0.9663 35 1.4515 0.9441 36 1.4338 0.9410 37 1.3970 0.9404 38 1.3684 0.9360 39 1.3397 0.9279 40 1.3360 0.9175 41 1.2871 0.9149 42 1.2862 0.9129 43 1.2645 0.9123 44 1.2399 0.9041 45 1.2007 0.9036 46 1.1990 0.8997 47 1.1824 0.8991 48 1.1686 0.8979 49 1.1423 0.8976 50 1.1235 0.8799 51 1.0732 0.8744 52 1.0454 0.8598 53 0.9697 0.8529 54 0.9031 0.8397 55 0.7656 0.8255 56 0.7255 0.8078 57 0.6821 0.7675 58 0.6779 0.7411 59 0.4502 0.7387 60 0.2396 0.7328 61 0.1629 0.7138 BP Model B 6/18/2021 11:40:54 AM Page 45 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.8639 17603 16305 92 Pass 0.8979 16198 14014 86 Pass 0.9320 14991 12350 82 Pass 0.9660 13877 10857 78 Pass 1.0000 12833 9567 74 Pass 1.0340 11834 8579 72 Pass 1.0680 10919 7820 71 Pass 1.1020 10138 7274 71 Pass 1.1360 9403 6859 72 Pass 1.1700 8750 6447 73 Pass 1.2040 8143 5991 73 Pass 1.2380 7593 5525 72 Pass 1.2720 7058 5067 71 Pass 1.3060 6588 4663 70 Pass 1.3400 6145 4250 69 Pass 1.3740 5777 3888 67 Pass 1.4080 5431 3568 65 Pass 1.4420 5097 3330 65 Pass 1.4761 4808 3112 64 Pass 1.5101 4524 2858 63 Pass 1.5441 4252 2618 61 Pass 1.5781 4017 2417 60 Pass 1.6121 3782 2254 59 Pass 1.6461 3546 2112 59 Pass 1.6801 3337 1965 58 Pass 1.7141 3138 1803 57 Pass 1.7481 2950 1669 56 Pass 1.7821 2785 1557 55 Pass 1.8161 2599 1432 55 Pass 1.8501 2447 1310 53 Pass 1.8841 2304 1191 51 Pass 1.9181 2160 1064 49 Pass 1.9521 2025 950 46 Pass 1.9861 1898 862 45 Pass 2.0201 1790 769 42 Pass 2.0542 1687 681 40 Pass 2.0882 1585 625 39 Pass 2.1222 1483 559 37 Pass 2.1562 1380 505 36 Pass 2.1902 1292 439 33 Pass 2.2242 1218 406 33 Pass 2.2582 1155 374 32 Pass 2.2922 1098 338 30 Pass 2.3262 1048 311 29 Pass 2.3602 997 282 28 Pass 2.3942 930 241 25 Pass 2.4282 883 211 23 Pass 2.4622 837 193 23 Pass 2.4962 789 173 21 Pass 2.5302 743 157 21 Pass 2.5642 713 148 20 Pass 2.5982 668 143 21 Pass 2.6323 630 138 21 Pass BP Model B 6/18/2021 11:40:54 AM Page 46 2.6663 596 131 21 Pass 2.7003 565 121 21 Pass 2.7343 539 115 21 Pass 2.7683 497 110 22 Pass 2.8023 473 108 22 Pass 2.8363 434 106 24 Pass 2.8703 399 103 25 Pass 2.9043 366 91 24 Pass 2.9383 348 81 23 Pass 2.9723 323 72 22 Pass 3.0063 296 66 22 Pass 3.0403 272 64 23 Pass 3.0743 256 61 23 Pass 3.1083 235 59 25 Pass 3.1423 217 54 24 Pass 3.1763 195 52 26 Pass 3.2104 180 46 25 Pass 3.2444 158 44 27 Pass 3.2784 145 40 27 Pass 3.3124 129 38 29 Pass 3.3464 119 35 29 Pass 3.3804 109 33 30 Pass 3.4144 97 30 30 Pass 3.4484 91 25 27 Pass 3.4824 82 14 17 Pass 3.5164 76 11 14 Pass 3.5504 69 10 14 Pass 3.5844 61 7 11 Pass 3.6184 54 3 5 Pass 3.6524 48 0 0 Pass 3.6864 41 0 0 Pass 3.7204 38 0 0 Pass 3.7545 33 0 0 Pass 3.7885 27 0 0 Pass 3.8225 22 0 0 Pass 3.8565 21 0 0 Pass 3.8905 20 0 0 Pass 3.9245 19 0 0 Pass 3.9585 17 0 0 Pass 3.9925 14 0 0 Pass 4.0265 12 0 0 Pass 4.0605 9 0 0 Pass 4.0945 4 0 0 Pass 4.1285 3 0 0 Pass 4.1625 3 0 0 Pass 4.1965 3 0 0 Pass 4.2305 3 0 0 Pass BP Model B 6/18/2021 11:40:54 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 6/18/2021 11:40:54 AM Page 48 LID Report BP Model B 6/18/2021 11:43:00 AM Page 49 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:22.6 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:3.23 Total Impervious Area:19.37 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.664459 5 year 1.043558 10 year 1.258401 25 year 1.486007 50 year 1.626851 100 year 1.746645 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.474058 5 year 0.692922 10 year 0.86278 25 year 1.107882 50 year 1.313986 100 year 1.541442 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.653 0.373 1950 0.814 0.463 1951 1.463 1.064 1952 0.461 0.304 1953 0.373 0.407 1954 0.573 0.339 1955 0.913 0.370 1956 0.727 0.673 1957 0.586 0.385 1958 0.661 0.395 1959 0.567 0.353 BP Model B 6/18/2021 11:43:29 AM Page 50 1960 0.989 0.857 1961 0.558 0.570 1962 0.347 0.291 1963 0.477 0.372 1964 0.628 0.522 1965 0.449 0.628 1966 0.432 0.368 1967 0.903 0.444 1968 0.564 0.364 1969 0.551 0.353 1970 0.455 0.384 1971 0.486 0.406 1972 1.090 0.841 1973 0.495 0.614 1974 0.537 0.366 1975 0.728 0.397 1976 0.526 0.344 1977 0.063 0.353 1978 0.462 0.458 1979 0.279 0.291 1980 1.033 0.890 1981 0.413 0.359 1982 0.794 0.826 1983 0.712 0.357 1984 0.439 0.320 1985 0.261 0.337 1986 1.152 0.524 1987 1.019 0.799 1988 0.402 0.360 1989 0.262 0.330 1990 2.130 0.859 1991 1.282 0.859 1992 0.495 0.432 1993 0.515 0.296 1994 0.173 0.284 1995 0.739 0.572 1996 1.557 1.010 1997 1.301 1.041 1998 0.294 0.358 1999 1.220 0.873 2000 0.514 0.448 2001 0.092 0.343 2002 0.563 0.591 2003 0.718 0.350 2004 0.930 1.099 2005 0.667 0.360 2006 0.787 0.675 2007 1.581 1.493 2008 2.039 0.965 2009 1.001 0.652 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 2.1300 1.4933 2 2.0395 1.0986 3 1.5810 1.0643 4 1.5569 1.0412 BP Model B 6/18/2021 11:43:29 AM Page 51 5 1.4632 1.0101 6 1.3015 0.9647 7 1.2825 0.8905 8 1.2205 0.8730 9 1.1517 0.8591 10 1.0896 0.8587 11 1.0326 0.8572 12 1.0187 0.8410 13 1.0014 0.8265 14 0.9894 0.7990 15 0.9299 0.6754 16 0.9131 0.6727 17 0.9035 0.6519 18 0.8139 0.6282 19 0.7937 0.6143 20 0.7867 0.5915 21 0.7387 0.5723 22 0.7279 0.5700 23 0.7266 0.5240 24 0.7182 0.5224 25 0.7116 0.4634 26 0.6671 0.4577 27 0.6606 0.4476 28 0.6527 0.4439 29 0.6276 0.4322 30 0.5864 0.4068 31 0.5727 0.4061 32 0.5667 0.3971 33 0.5636 0.3951 34 0.5630 0.3851 35 0.5582 0.3845 36 0.5514 0.3727 37 0.5372 0.3723 38 0.5262 0.3697 39 0.5152 0.3684 40 0.5137 0.3664 41 0.4950 0.3643 42 0.4946 0.3603 43 0.4863 0.3599 44 0.4768 0.3592 45 0.4617 0.3578 46 0.4611 0.3574 47 0.4547 0.3533 48 0.4494 0.3529 49 0.4393 0.3526 50 0.4320 0.3496 51 0.4127 0.3438 52 0.4020 0.3431 53 0.3729 0.3390 54 0.3473 0.3366 55 0.2944 0.3300 56 0.2790 0.3202 57 0.2623 0.3039 58 0.2607 0.2957 59 0.1731 0.2912 60 0.0921 0.2912 61 0.0626 0.2845 BP Model B 6/18/2021 11:43:29 AM Page 53 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.3322 17582 17053 96 Pass 0.3453 16196 14929 92 Pass 0.3584 14994 13798 92 Pass 0.3715 13881 12951 93 Pass 0.3845 12850 11914 92 Pass 0.3976 11860 10797 91 Pass 0.4107 10938 9627 88 Pass 0.4238 10155 8519 83 Pass 0.4368 9426 7694 81 Pass 0.4499 8778 7368 83 Pass 0.4630 8190 7101 86 Pass 0.4761 7593 6812 89 Pass 0.4892 7065 6577 93 Pass 0.5022 6594 6325 95 Pass 0.5153 6154 5961 96 Pass 0.5284 5784 5608 96 Pass 0.5415 5443 5247 96 Pass 0.5545 5110 4849 94 Pass 0.5676 4817 4483 93 Pass 0.5807 4539 4190 92 Pass 0.5938 4267 3910 91 Pass 0.6068 4032 3640 90 Pass 0.6199 3801 3418 89 Pass 0.6330 3546 3157 89 Pass 0.6461 3339 2928 87 Pass 0.6592 3138 2620 83 Pass 0.6722 2954 2411 81 Pass 0.6853 2789 2261 81 Pass 0.6984 2601 2117 81 Pass 0.7115 2451 1951 79 Pass 0.7245 2312 1801 77 Pass 0.7376 2165 1662 76 Pass 0.7507 2032 1550 76 Pass 0.7638 1908 1444 75 Pass 0.7768 1793 1353 75 Pass 0.7899 1697 1236 72 Pass 0.8030 1583 1127 71 Pass 0.8161 1483 1040 70 Pass 0.8292 1381 957 69 Pass 0.8422 1293 849 65 Pass 0.8553 1222 747 61 Pass 0.8684 1155 674 58 Pass 0.8815 1098 610 55 Pass 0.8945 1049 544 51 Pass 0.9076 998 490 49 Pass 0.9207 930 438 47 Pass 0.9338 884 395 44 Pass 0.9468 841 359 42 Pass 0.9599 790 326 41 Pass 0.9730 743 297 39 Pass 0.9861 713 275 38 Pass 0.9992 668 250 37 Pass 1.0122 631 227 35 Pass BP Model B 6/18/2021 11:43:29 AM Page 54 1.0253 596 209 35 Pass 1.0384 567 188 33 Pass 1.0515 539 167 30 Pass 1.0645 497 148 29 Pass 1.0776 473 132 27 Pass 1.0907 437 125 28 Pass 1.1038 402 114 28 Pass 1.1168 370 111 30 Pass 1.1299 348 108 31 Pass 1.1430 323 105 32 Pass 1.1561 296 94 31 Pass 1.1692 272 84 30 Pass 1.1822 256 78 30 Pass 1.1953 235 72 30 Pass 1.2084 217 70 32 Pass 1.2215 198 68 34 Pass 1.2345 180 66 36 Pass 1.2476 158 64 40 Pass 1.2607 145 63 43 Pass 1.2738 130 62 47 Pass 1.2868 119 60 50 Pass 1.2999 110 59 53 Pass 1.3130 97 57 58 Pass 1.3261 91 54 59 Pass 1.3392 82 52 63 Pass 1.3522 76 47 61 Pass 1.3653 69 45 65 Pass 1.3784 61 42 68 Pass 1.3915 54 39 72 Pass 1.4045 48 38 79 Pass 1.4176 41 35 85 Pass 1.4307 38 33 86 Pass 1.4438 33 26 78 Pass 1.4569 27 20 74 Pass 1.4699 22 17 77 Pass 1.4830 21 10 47 Pass 1.4961 20 0 0 Pass 1.5092 19 0 0 Pass 1.5222 17 0 0 Pass 1.5353 14 0 0 Pass 1.5484 12 0 0 Pass 1.5615 9 0 0 Pass 1.5745 4 0 0 Pass 1.5876 3 0 0 Pass 1.6007 3 0 0 Pass 1.6138 3 0 0 Pass 1.6269 3 0 0 Pass BP Model B 6/18/2021 11:43:29 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 6/18/2021 11:43:29 AM Page 56 LID Report BP Model B 6/18/2021 11:43:29 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 6/18/2021 11:43:58 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 6/18/2021 11:43:58 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 6/18/2021 11:43:58 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 6/18/2021 11:43:59 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 6/18/2021 11:43:59 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 6/18/2021 11:43:59 AM Page 64 LID Report BP Model B 6/18/2021 11:43:59 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 6/18/2021 11:44:28 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 6/18/2021 11:44:28 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 6/18/2021 11:44:28 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 6/18/2021 11:44:28 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 6/18/2021 11:44:28 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 6/18/2021 11:44:28 AM Page 72 LID Report BP Model B 6/18/2021 11:44:28 AM Page 73 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:13.8 Total Impervious Area:0 Mitigated Landuse Totals for POC #5 Total Pervious Area:2.7 Total Impervious Area:11.1 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.405732 5 year 0.637217 10 year 0.768404 25 year 0.907385 50 year 0.993387 100 year 1.066536 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 0.374672 5 year 0.519675 10 year 0.627762 25 year 0.778731 50 year 0.902089 100 year 1.035161 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.399 0.395 1950 0.497 0.392 1951 0.893 0.782 1952 0.282 0.245 1953 0.228 0.293 1954 0.350 0.295 1955 0.558 0.329 1956 0.444 0.491 1957 0.358 0.353 1958 0.403 0.279 1959 0.346 0.275 BP Model B 6/18/2021 11:44:58 AM Page 74 1960 0.604 0.571 1961 0.341 0.441 1962 0.212 0.241 1963 0.291 0.305 1964 0.383 0.349 1965 0.274 0.398 1966 0.264 0.298 1967 0.552 0.397 1968 0.344 0.378 1969 0.337 0.319 1970 0.278 0.298 1971 0.297 0.353 1972 0.665 0.645 1973 0.302 0.396 1974 0.328 0.346 1975 0.444 0.363 1976 0.321 0.297 1977 0.038 0.282 1978 0.282 0.311 1979 0.170 0.341 1980 0.631 0.611 1981 0.252 0.336 1982 0.485 0.682 1983 0.435 0.334 1984 0.268 0.249 1985 0.159 0.311 1986 0.703 0.339 1987 0.622 0.553 1988 0.245 0.264 1989 0.160 0.246 1990 1.301 0.689 1991 0.783 0.685 1992 0.302 0.271 1993 0.315 0.215 1994 0.106 0.209 1995 0.451 0.389 1996 0.951 0.732 1997 0.795 0.721 1998 0.180 0.303 1999 0.745 0.603 2000 0.314 0.338 2001 0.056 0.320 2002 0.344 0.436 2003 0.439 0.336 2004 0.568 0.762 2005 0.407 0.312 2006 0.480 0.485 2007 0.965 0.970 2008 1.245 0.721 2009 0.611 0.422 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #5 Rank Predeveloped Mitigated 1 1.3006 0.9703 2 1.2453 0.7819 3 0.9654 0.7625 4 0.9507 0.7318 BP Model B 6/18/2021 11:44:58 AM Page 75 5 0.8935 0.7208 6 0.7947 0.7207 7 0.7831 0.6890 8 0.7452 0.6852 9 0.7032 0.6820 10 0.6654 0.6448 11 0.6306 0.6114 12 0.6221 0.6033 13 0.6115 0.5713 14 0.6041 0.5528 15 0.5678 0.4910 16 0.5576 0.4847 17 0.5517 0.4414 18 0.4970 0.4356 19 0.4847 0.4223 20 0.4804 0.3981 21 0.4511 0.3965 22 0.4445 0.3958 23 0.4437 0.3952 24 0.4386 0.3918 25 0.4345 0.3888 26 0.4074 0.3779 27 0.4034 0.3626 28 0.3986 0.3530 29 0.3832 0.3530 30 0.3581 0.3489 31 0.3497 0.3458 32 0.3460 0.3408 33 0.3441 0.3390 34 0.3438 0.3380 35 0.3408 0.3365 36 0.3367 0.3356 37 0.3280 0.3337 38 0.3213 0.3286 39 0.3146 0.3203 40 0.3137 0.3193 41 0.3022 0.3124 42 0.3020 0.3114 43 0.2969 0.3108 44 0.2911 0.3054 45 0.2819 0.3032 46 0.2815 0.2979 47 0.2776 0.2976 48 0.2744 0.2970 49 0.2682 0.2950 50 0.2638 0.2930 51 0.2520 0.2824 52 0.2455 0.2794 53 0.2277 0.2753 54 0.2121 0.2709 55 0.1798 0.2637 56 0.1704 0.2489 57 0.1602 0.2463 58 0.1592 0.2447 59 0.1057 0.2406 60 0.0563 0.2152 61 0.0382 0.2086 BP Model B 6/18/2021 11:44:58 AM Page 77 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2029 17729 16694 94 Pass 0.2109 16303 14185 87 Pass 0.2188 15075 12089 80 Pass 0.2268 13941 10836 77 Pass 0.2348 12910 9924 76 Pass 0.2428 11916 9300 78 Pass 0.2508 10977 8739 79 Pass 0.2588 10175 8248 81 Pass 0.2667 9445 7741 81 Pass 0.2747 8789 7176 81 Pass 0.2827 8198 6714 81 Pass 0.2907 7644 6303 82 Pass 0.2987 7103 5878 82 Pass 0.3067 6613 5503 83 Pass 0.3147 6175 5138 83 Pass 0.3226 5799 4825 83 Pass 0.3306 5456 4554 83 Pass 0.3386 5129 4263 83 Pass 0.3466 4821 4025 83 Pass 0.3546 4545 3794 83 Pass 0.3626 4267 3574 83 Pass 0.3706 4034 3356 83 Pass 0.3785 3801 3159 83 Pass 0.3865 3559 2973 83 Pass 0.3945 3347 2823 84 Pass 0.4025 3146 2678 85 Pass 0.4105 2960 2532 85 Pass 0.4185 2791 2400 85 Pass 0.4264 2603 2252 86 Pass 0.4344 2451 2130 86 Pass 0.4424 2312 2002 86 Pass 0.4504 2165 1875 86 Pass 0.4584 2032 1770 87 Pass 0.4664 1906 1655 86 Pass 0.4744 1791 1562 87 Pass 0.4823 1694 1486 87 Pass 0.4903 1592 1411 88 Pass 0.4983 1484 1328 89 Pass 0.5063 1383 1249 90 Pass 0.5143 1293 1186 91 Pass 0.5223 1222 1113 91 Pass 0.5303 1155 1033 89 Pass 0.5382 1098 965 87 Pass 0.5462 1049 891 84 Pass 0.5542 997 814 81 Pass 0.5622 930 747 80 Pass 0.5702 884 681 77 Pass 0.5782 838 622 74 Pass 0.5861 789 558 70 Pass 0.5941 743 498 67 Pass 0.6021 713 452 63 Pass 0.6101 668 412 61 Pass 0.6181 631 386 61 Pass BP Model B 6/18/2021 11:44:58 AM Page 78 0.6261 596 361 60 Pass 0.6341 565 339 60 Pass 0.6420 539 318 58 Pass 0.6500 496 299 60 Pass 0.6580 473 273 57 Pass 0.6660 434 247 56 Pass 0.6740 404 235 58 Pass 0.6820 373 217 58 Pass 0.6900 350 195 55 Pass 0.6979 326 176 53 Pass 0.7059 299 159 53 Pass 0.7139 276 148 53 Pass 0.7219 258 133 51 Pass 0.7299 237 124 52 Pass 0.7379 218 117 53 Pass 0.7459 201 107 53 Pass 0.7538 182 98 53 Pass 0.7618 158 89 56 Pass 0.7698 146 77 52 Pass 0.7778 131 69 52 Pass 0.7858 119 66 55 Pass 0.7938 110 60 54 Pass 0.8017 97 58 59 Pass 0.8097 92 53 57 Pass 0.8177 82 47 57 Pass 0.8257 77 45 58 Pass 0.8337 69 43 62 Pass 0.8417 62 42 67 Pass 0.8497 55 39 70 Pass 0.8576 48 36 75 Pass 0.8656 41 29 70 Pass 0.8736 38 27 71 Pass 0.8816 33 21 63 Pass 0.8896 27 16 59 Pass 0.8976 22 13 59 Pass 0.9056 21 9 42 Pass 0.9135 20 8 40 Pass 0.9215 19 5 26 Pass 0.9295 17 2 11 Pass 0.9375 14 2 14 Pass 0.9455 12 1 8 Pass 0.9535 9 1 11 Pass 0.9614 4 1 25 Pass 0.9694 3 1 33 Pass 0.9774 3 0 0 Pass 0.9854 3 0 0 Pass 0.9934 3 0 0 Pass BP Model B 6/18/2021 11:44:58 AM Page 79 Water Quality Water Quality BMP Flow and Volume for POC #5 On-line facility volume:0.3421 acre-feet On-line facility target flow:0.1751 cfs. Adjusted for 15 min:0.1751 cfs. Off-line facility target flow:0.1193 cfs. Adjusted for 15 min:0.1193 cfs. BP Model B 6/18/2021 11:44:58 AM Page 80 LID Report BP Model B 6/18/2021 11:44:58 AM Page 81 POC 6 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #6 Total Pervious Area:1.53 Total Impervious Area:5.06 Mitigated Landuse Totals for POC #6 Total Pervious Area:1.53 Total Impervious Area:5.06 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 2.026897 5 year 2.595749 10 year 2.986368 25 year 3.497297 50 year 3.89122 100 year 4.297028 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 2.026897 5 year 2.595749 10 year 2.986368 25 year 3.497297 50 year 3.89122 100 year 4.297028 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 2.721 2.721 1950 2.735 2.735 1951 1.695 1.695 1952 1.405 1.405 1953 1.519 1.519 1954 1.651 1.651 1955 1.849 1.849 1956 1.826 1.826 1957 2.132 2.132 1958 1.656 1.656 1959 1.635 1.635 BP Model B 6/18/2021 11:45:29 AM Page 82 1960 1.752 1.752 1961 1.803 1.803 1962 1.510 1.510 1963 1.746 1.746 1964 1.641 1.641 1965 2.212 2.212 1966 1.422 1.422 1967 2.469 2.469 1968 2.812 2.812 1969 2.011 2.011 1970 1.892 1.892 1971 2.259 2.259 1972 2.458 2.458 1973 1.341 1.341 1974 2.092 2.092 1975 2.254 2.254 1976 1.618 1.618 1977 1.643 1.643 1978 2.022 2.022 1979 2.775 2.775 1980 2.771 2.771 1981 2.104 2.104 1982 3.034 3.034 1983 2.369 2.369 1984 1.531 1.531 1985 2.107 2.107 1986 1.784 1.784 1987 2.739 2.739 1988 1.632 1.632 1989 2.041 2.041 1990 4.013 4.013 1991 3.106 3.106 1992 1.517 1.517 1993 1.285 1.285 1994 1.362 1.362 1995 1.856 1.856 1996 2.087 2.087 1997 1.996 1.996 1998 1.922 1.922 1999 4.135 4.135 2000 2.019 2.019 2001 2.125 2.125 2002 2.674 2.674 2003 2.078 2.078 2004 3.846 3.846 2005 1.764 1.764 2006 1.579 1.579 2007 3.618 3.618 2008 3.050 3.050 2009 2.498 2.498 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #6 Rank Predeveloped Mitigated 1 4.1354 4.1354 2 4.0131 4.0131 3 3.8460 3.8460 4 3.6183 3.6183 BP Model B 6/18/2021 11:45:29 AM Page 83 5 3.1057 3.1057 6 3.0496 3.0496 7 3.0336 3.0336 8 2.8123 2.8123 9 2.7753 2.7753 10 2.7708 2.7708 11 2.7389 2.7389 12 2.7354 2.7354 13 2.7206 2.7206 14 2.6743 2.6743 15 2.4977 2.4977 16 2.4694 2.4694 17 2.4577 2.4577 18 2.3689 2.3689 19 2.2585 2.2585 20 2.2541 2.2541 21 2.2117 2.2117 22 2.1317 2.1317 23 2.1245 2.1245 24 2.1067 2.1067 25 2.1042 2.1042 26 2.0918 2.0918 27 2.0868 2.0868 28 2.0784 2.0784 29 2.0412 2.0412 30 2.0224 2.0224 31 2.0186 2.0186 32 2.0109 2.0109 33 1.9959 1.9959 34 1.9223 1.9223 35 1.8924 1.8924 36 1.8564 1.8564 37 1.8488 1.8488 38 1.8256 1.8256 39 1.8032 1.8032 40 1.7842 1.7842 41 1.7636 1.7636 42 1.7521 1.7521 43 1.7458 1.7458 44 1.6948 1.6948 45 1.6564 1.6564 46 1.6512 1.6512 47 1.6434 1.6434 48 1.6412 1.6412 49 1.6353 1.6353 50 1.6322 1.6322 51 1.6184 1.6184 52 1.5786 1.5786 53 1.5314 1.5314 54 1.5185 1.5185 55 1.5171 1.5171 56 1.5105 1.5105 57 1.4218 1.4218 58 1.4054 1.4054 59 1.3621 1.3621 60 1.3406 1.3406 61 1.2851 1.2851 BP Model B 6/18/2021 11:45:29 AM Page 85 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 1.0134 1701 1701 100 Pass 1.0425 1558 1558 100 Pass 1.0716 1409 1409 100 Pass 1.1007 1269 1269 100 Pass 1.1297 1135 1135 100 Pass 1.1588 1039 1039 100 Pass 1.1879 954 954 100 Pass 1.2169 874 874 100 Pass 1.2460 793 793 100 Pass 1.2751 726 726 100 Pass 1.3041 667 667 100 Pass 1.3332 620 620 100 Pass 1.3623 571 571 100 Pass 1.3913 534 534 100 Pass 1.4204 497 497 100 Pass 1.4495 453 453 100 Pass 1.4785 414 414 100 Pass 1.5076 387 387 100 Pass 1.5367 362 362 100 Pass 1.5657 344 344 100 Pass 1.5948 318 318 100 Pass 1.6239 294 294 100 Pass 1.6530 273 273 100 Pass 1.6820 254 254 100 Pass 1.7111 237 237 100 Pass 1.7402 224 224 100 Pass 1.7692 206 206 100 Pass 1.7983 195 195 100 Pass 1.8274 184 184 100 Pass 1.8564 171 171 100 Pass 1.8855 158 158 100 Pass 1.9146 148 148 100 Pass 1.9436 138 138 100 Pass 1.9727 130 130 100 Pass 2.0018 125 125 100 Pass 2.0308 114 114 100 Pass 2.0599 109 109 100 Pass 2.0890 104 104 100 Pass 2.1180 95 95 100 Pass 2.1471 88 88 100 Pass 2.1762 82 82 100 Pass 2.2053 81 81 100 Pass 2.2343 79 79 100 Pass 2.2634 76 76 100 Pass 2.2925 73 73 100 Pass 2.3215 68 68 100 Pass 2.3506 65 65 100 Pass 2.3797 62 62 100 Pass 2.4087 57 57 100 Pass 2.4378 56 56 100 Pass 2.4669 52 52 100 Pass 2.4959 48 48 100 Pass 2.5250 47 47 100 Pass BP Model B 6/18/2021 11:45:29 AM Page 86 2.5541 45 45 100 Pass 2.5831 41 41 100 Pass 2.6122 40 40 100 Pass 2.6413 39 39 100 Pass 2.6703 33 33 100 Pass 2.6994 31 31 100 Pass 2.7285 29 29 100 Pass 2.7576 27 27 100 Pass 2.7866 22 22 100 Pass 2.8157 21 21 100 Pass 2.8448 20 20 100 Pass 2.8738 18 18 100 Pass 2.9029 16 16 100 Pass 2.9320 16 16 100 Pass 2.9610 15 15 100 Pass 2.9901 14 14 100 Pass 3.0192 13 13 100 Pass 3.0482 11 11 100 Pass 3.0773 9 9 100 Pass 3.1064 8 8 100 Pass 3.1354 8 8 100 Pass 3.1645 8 8 100 Pass 3.1936 8 8 100 Pass 3.2226 8 8 100 Pass 3.2517 8 8 100 Pass 3.2808 8 8 100 Pass 3.3099 8 8 100 Pass 3.3389 8 8 100 Pass 3.3680 8 8 100 Pass 3.3971 8 8 100 Pass 3.4261 7 7 100 Pass 3.4552 7 7 100 Pass 3.4843 7 7 100 Pass 3.5133 7 7 100 Pass 3.5424 7 7 100 Pass 3.5715 7 7 100 Pass 3.6005 6 6 100 Pass 3.6296 5 5 100 Pass 3.6587 5 5 100 Pass 3.6877 4 4 100 Pass 3.7168 4 4 100 Pass 3.7459 4 4 100 Pass 3.7749 4 4 100 Pass 3.8040 3 3 100 Pass 3.8331 3 3 100 Pass 3.8622 2 2 100 Pass 3.8912 2 2 100 Pass BP Model B 6/18/2021 11:45:29 AM Page 87 Water Quality Water Quality BMP Flow and Volume for POC #6 On-line facility volume:0.6693 acre-feet On-line facility target flow:0.8116 cfs. Adjusted for 15 min:0.8116 cfs. Off-line facility target flow:0.4568 cfs. Adjusted for 15 min:0.4568 cfs. BP Model B 6/18/2021 11:45:29 AM Page 88 LID Report BP Model B 6/18/2021 11:45:30 AM Page 91 Appendix Predeveloped Schematic BP Model B 6/18/2021 11:45:30 AM Page 92 Mitigated Schematic BP Model B 6/18/2021 11:45:31 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. 2005-2021; 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 6/18/2021 1:40:55 PM Page 2 General Model Information Project Name:BP Model C Site Name:Business Park Site Address:Model C - Pond 5 Reduced City: Report Date:6/18/2021 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:0.000 (adjusted) Version Date:2019/09/13 Version:4.2.17 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 6/18/2021 1:40:55 PM 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 6/18/2021 1:40:55 PM Page 4 PreDev - Basin 5 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 12.12 Pervious Total 12.12 Impervious Land Use acre Impervious Total 0 Basin Total 12.12 Element Flows To: Surface Interflow Groundwater BP Model C 6/18/2021 1:40:55 PM Page 5 PreDev - Basin 5 - WQ Node Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.53 Pervious Total 1.53 Impervious Land Use acre ROADS FLAT 5.06 Impervious Total 5.06 Basin Total 6.59 Element Flows To: Surface Interflow Groundwater BP Model C 6/18/2021 1:40:55 PM 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 6/18/2021 1:40:55 PM 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 6/18/2021 1:40:55 PM Page 8 Dev - Basin 5 - PGIS Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.53 Pervious Total 1.53 Impervious Land Use acre ROADS FLAT 5.06 Impervious Total 5.06 Basin Total 6.59 Element Flows To: Surface Interflow Groundwater Pond 5 - 4:1 SS Pond 5 - 4:1 SS BP Model C 6/18/2021 1:40:55 PM 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 6/18/2021 1:40:55 PM 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 6/18/2021 1:40:55 PM Page 17 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:13.05 Total Impervious Area:0 Mitigated Landuse Totals for POC #5 Total Pervious Area:2.46 Total Impervious Area:10.59 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.383681 5 year 0.602586 10 year 0.726643 25 year 0.858071 50 year 0.939399 100 year 1.008572 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 1.065 5 year 1.872949 10 year 2.531724 25 year 3.508092 50 year 4.342325 100 year 5.270288 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.377 0.908 1950 0.470 1.301 1951 0.845 1.879 1952 0.266 0.438 1953 0.215 0.762 1954 0.331 0.840 1955 0.527 1.650 1956 0.420 1.254 1957 0.339 1.381 1958 0.381 0.983 1959 0.327 1.065 BP Model C 6/18/2021 1:41:24 PM Page 18 1960 0.571 1.686 1961 0.322 0.994 1962 0.201 0.334 1963 0.275 1.004 1964 0.362 0.755 1965 0.259 1.055 1966 0.249 0.569 1967 0.522 1.543 1968 0.325 0.672 1969 0.318 0.864 1970 0.263 0.700 1971 0.281 1.223 1972 0.629 1.506 1973 0.286 0.722 1974 0.310 0.754 1975 0.420 1.576 1976 0.304 0.854 1977 0.036 0.413 1978 0.267 0.811 1979 0.161 0.339 1980 0.596 1.671 1981 0.238 0.579 1982 0.458 2.453 1983 0.411 1.180 1984 0.254 0.374 1985 0.151 0.935 1986 0.665 2.029 1987 0.588 2.268 1988 0.232 0.563 1989 0.151 0.357 1990 1.230 4.016 1991 0.741 2.788 1992 0.286 0.629 1993 0.297 0.815 1994 0.100 0.314 1995 0.427 1.298 1996 0.899 2.176 1997 0.752 2.105 1998 0.170 0.990 1999 0.705 1.668 2000 0.297 1.031 2001 0.053 0.416 2002 0.325 2.160 2003 0.415 0.484 2004 0.537 5.025 2005 0.385 1.343 2006 0.454 1.248 2007 0.913 3.894 2008 1.178 3.980 2009 0.578 2.125 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #5 Rank Predeveloped Mitigated 1 1.2299 5.0254 2 1.1777 4.0155 3 0.9129 3.9801 4 0.8990 3.8945 BP Model C 6/18/2021 1:41:24 PM Page 19 5 0.8449 2.7877 6 0.7515 2.4528 7 0.7406 2.2685 8 0.7047 2.1759 9 0.6650 2.1597 10 0.6292 2.1246 11 0.5963 2.1053 12 0.5882 2.0287 13 0.5782 1.8794 14 0.5713 1.6864 15 0.5370 1.6705 16 0.5273 1.6683 17 0.5217 1.6496 18 0.4699 1.5759 19 0.4583 1.5432 20 0.4543 1.5058 21 0.4266 1.3810 22 0.4203 1.3432 23 0.4196 1.3012 24 0.4147 1.2979 25 0.4109 1.2540 26 0.3852 1.2482 27 0.3815 1.2226 28 0.3769 1.1804 29 0.3624 1.0645 30 0.3386 1.0551 31 0.3307 1.0307 32 0.3272 1.0037 33 0.3254 0.9942 34 0.3251 0.9904 35 0.3223 0.9830 36 0.3184 0.9352 37 0.3102 0.9084 38 0.3039 0.8643 39 0.2975 0.8540 40 0.2967 0.8397 41 0.2858 0.8148 42 0.2856 0.8110 43 0.2808 0.7617 44 0.2753 0.7552 45 0.2666 0.7544 46 0.2662 0.7219 47 0.2625 0.6999 48 0.2595 0.6718 49 0.2537 0.6294 50 0.2495 0.5788 51 0.2383 0.5689 52 0.2321 0.5630 53 0.2153 0.4843 54 0.2005 0.4381 55 0.1700 0.4157 56 0.1611 0.4132 57 0.1515 0.3744 58 0.1505 0.3574 59 0.1000 0.3395 60 0.0532 0.3339 61 0.0362 0.3139 BP Model C 6/18/2021 1:41:26 PM Page 25 POC 6 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #6 Total Pervious Area:1.53 Total Impervious Area:5.06 Mitigated Landuse Totals for POC #6 Total Pervious Area:1.53 Total Impervious Area:5.06 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 2.026897 5 year 2.595749 10 year 2.986368 25 year 3.497297 50 year 3.89122 100 year 4.297028 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 2.026897 5 year 2.595749 10 year 2.986368 25 year 3.497297 50 year 3.89122 100 year 4.297028 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 2.721 2.721 1950 2.735 2.735 1951 1.695 1.695 1952 1.405 1.405 1953 1.519 1.519 1954 1.651 1.651 1955 1.849 1.849 1956 1.826 1.826 1957 2.132 2.132 1958 1.656 1.656 1959 1.635 1.635 BP Model C 6/18/2021 1:41:56 PM Page 26 1960 1.752 1.752 1961 1.803 1.803 1962 1.510 1.510 1963 1.746 1.746 1964 1.641 1.641 1965 2.212 2.212 1966 1.422 1.422 1967 2.469 2.469 1968 2.812 2.812 1969 2.011 2.011 1970 1.892 1.892 1971 2.259 2.259 1972 2.458 2.458 1973 1.341 1.341 1974 2.092 2.092 1975 2.254 2.254 1976 1.618 1.618 1977 1.643 1.643 1978 2.022 2.022 1979 2.775 2.775 1980 2.771 2.771 1981 2.104 2.104 1982 3.034 3.034 1983 2.369 2.369 1984 1.531 1.531 1985 2.107 2.107 1986 1.784 1.784 1987 2.739 2.739 1988 1.632 1.632 1989 2.041 2.041 1990 4.013 4.013 1991 3.106 3.106 1992 1.517 1.517 1993 1.285 1.285 1994 1.362 1.362 1995 1.856 1.856 1996 2.087 2.087 1997 1.996 1.996 1998 1.922 1.922 1999 4.135 4.135 2000 2.019 2.019 2001 2.125 2.125 2002 2.674 2.674 2003 2.078 2.078 2004 3.846 3.846 2005 1.764 1.764 2006 1.579 1.579 2007 3.618 3.618 2008 3.050 3.050 2009 2.498 2.498 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #6 Rank Predeveloped Mitigated 1 4.1354 4.1354 2 4.0131 4.0131 3 3.8460 3.8460 4 3.6183 3.6183 BP Model C 6/18/2021 1:41:56 PM Page 27 5 3.1057 3.1057 6 3.0496 3.0496 7 3.0336 3.0336 8 2.8123 2.8123 9 2.7753 2.7753 10 2.7708 2.7708 11 2.7389 2.7389 12 2.7354 2.7354 13 2.7206 2.7206 14 2.6743 2.6743 15 2.4977 2.4977 16 2.4694 2.4694 17 2.4577 2.4577 18 2.3689 2.3689 19 2.2585 2.2585 20 2.2541 2.2541 21 2.2117 2.2117 22 2.1317 2.1317 23 2.1245 2.1245 24 2.1067 2.1067 25 2.1042 2.1042 26 2.0918 2.0918 27 2.0868 2.0868 28 2.0784 2.0784 29 2.0412 2.0412 30 2.0224 2.0224 31 2.0186 2.0186 32 2.0109 2.0109 33 1.9959 1.9959 34 1.9223 1.9223 35 1.8924 1.8924 36 1.8564 1.8564 37 1.8488 1.8488 38 1.8256 1.8256 39 1.8032 1.8032 40 1.7842 1.7842 41 1.7636 1.7636 42 1.7521 1.7521 43 1.7458 1.7458 44 1.6948 1.6948 45 1.6564 1.6564 46 1.6512 1.6512 47 1.6434 1.6434 48 1.6412 1.6412 49 1.6353 1.6353 50 1.6322 1.6322 51 1.6184 1.6184 52 1.5786 1.5786 53 1.5314 1.5314 54 1.5185 1.5185 55 1.5171 1.5171 56 1.5105 1.5105 57 1.4218 1.4218 58 1.4054 1.4054 59 1.3621 1.3621 60 1.3406 1.3406 61 1.2851 1.2851 BP Model C 6/18/2021 1:41:56 PM Page 29 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 1.0134 1701 1701 100 Pass 1.0425 1558 1558 100 Pass 1.0716 1409 1409 100 Pass 1.1007 1269 1269 100 Pass 1.1297 1135 1135 100 Pass 1.1588 1039 1039 100 Pass 1.1879 954 954 100 Pass 1.2169 874 874 100 Pass 1.2460 793 793 100 Pass 1.2751 726 726 100 Pass 1.3041 667 667 100 Pass 1.3332 620 620 100 Pass 1.3623 571 571 100 Pass 1.3913 534 534 100 Pass 1.4204 497 497 100 Pass 1.4495 453 453 100 Pass 1.4785 414 414 100 Pass 1.5076 387 387 100 Pass 1.5367 362 362 100 Pass 1.5657 344 344 100 Pass 1.5948 318 318 100 Pass 1.6239 294 294 100 Pass 1.6530 273 273 100 Pass 1.6820 254 254 100 Pass 1.7111 237 237 100 Pass 1.7402 224 224 100 Pass 1.7692 206 206 100 Pass 1.7983 195 195 100 Pass 1.8274 184 184 100 Pass 1.8564 171 171 100 Pass 1.8855 158 158 100 Pass 1.9146 148 148 100 Pass 1.9436 138 138 100 Pass 1.9727 130 130 100 Pass 2.0018 125 125 100 Pass 2.0308 114 114 100 Pass 2.0599 109 109 100 Pass 2.0890 104 104 100 Pass 2.1180 95 95 100 Pass 2.1471 88 88 100 Pass 2.1762 82 82 100 Pass 2.2053 81 81 100 Pass 2.2343 79 79 100 Pass 2.2634 76 76 100 Pass 2.2925 73 73 100 Pass 2.3215 68 68 100 Pass 2.3506 65 65 100 Pass 2.3797 62 62 100 Pass 2.4087 57 57 100 Pass 2.4378 56 56 100 Pass 2.4669 52 52 100 Pass 2.4959 48 48 100 Pass 2.5250 47 47 100 Pass BP Model C 6/18/2021 1:41:56 PM Page 30 2.5541 45 45 100 Pass 2.5831 41 41 100 Pass 2.6122 40 40 100 Pass 2.6413 39 39 100 Pass 2.6703 33 33 100 Pass 2.6994 31 31 100 Pass 2.7285 29 29 100 Pass 2.7576 27 27 100 Pass 2.7866 22 22 100 Pass 2.8157 21 21 100 Pass 2.8448 20 20 100 Pass 2.8738 18 18 100 Pass 2.9029 16 16 100 Pass 2.9320 16 16 100 Pass 2.9610 15 15 100 Pass 2.9901 14 14 100 Pass 3.0192 13 13 100 Pass 3.0482 11 11 100 Pass 3.0773 9 9 100 Pass 3.1064 8 8 100 Pass 3.1354 8 8 100 Pass 3.1645 8 8 100 Pass 3.1936 8 8 100 Pass 3.2226 8 8 100 Pass 3.2517 8 8 100 Pass 3.2808 8 8 100 Pass 3.3099 8 8 100 Pass 3.3389 8 8 100 Pass 3.3680 8 8 100 Pass 3.3971 8 8 100 Pass 3.4261 7 7 100 Pass 3.4552 7 7 100 Pass 3.4843 7 7 100 Pass 3.5133 7 7 100 Pass 3.5424 7 7 100 Pass 3.5715 7 7 100 Pass 3.6005 6 6 100 Pass 3.6296 5 5 100 Pass 3.6587 5 5 100 Pass 3.6877 4 4 100 Pass 3.7168 4 4 100 Pass 3.7459 4 4 100 Pass 3.7749 4 4 100 Pass 3.8040 3 3 100 Pass 3.8331 3 3 100 Pass 3.8622 2 2 100 Pass 3.8912 2 2 100 Pass BP Model C 6/18/2021 1:41:56 PM Page 31 Water Quality Water Quality BMP Flow and Volume for POC #6 On-line facility volume:0.6693 acre-feet On-line facility target flow:0.8116 cfs. Adjusted for 15 min:0.8116 cfs. Off-line facility target flow:0.4568 cfs. Adjusted for 15 min:0.4568 cfs. BP Model C 6/18/2021 1:41:56 PM Page 35 Appendix Predeveloped Schematic BP Model C 6/18/2021 1:41:57 PM Page 36 Mitigated Schematic BP Model C 6/18/2021 1:41:57 PM 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. 2005-2021; 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