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23-106053 - TIR -12-27-2023Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Preliminary Technical Information Report PREPARED FOR: City of Federal Way Desireé S. Winkler, PE Deputy Public Works Director 33325 8th Avenue South Federal Way, WA 98003 PROJECT: City of Federal Way Operations & Maintenance Facility 31132 28th Avenue South Federal Way, WA 98003 2200572.12 PREPARED BY: Dan Osier, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: December 2023 Preliminary Technical Information Report PREPARED FOR: City of Federal Way Desireé S. Winkler, PE Deputy Public Works Director 33325 8th Avenue South Federal Way, WA 98003 PROJECT: City of Federal Way Operations & Maintenance Facility 31132 28th Avenue South Federal Way, WA 98003 2200572.12 PREPARED BY: Dan Osier, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: December 2023 I hereby state that this Preliminary Technical Information Report for the City of Federal Way Operations & Maintenance Facility project has been prepared by me or under my supervision, and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Federal Way does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Table of Contents Section Page 1.0 Project Overview ............................................................................................................................ 1 1.1 Purpose and Scope............................................................................................................. 1 1.2 Existing Conditions.............................................................................................................. 1 1.3 Developed Conditions ......................................................................................................... 1 1.4 Drainage Basins .................................................................................................................. 2 1.5 Soil Conditions .................................................................................................................... 2 2.0 Conditions and Requirements Summary .................................................................................... 2 2.1 Core Requirements ............................................................................................................. 2 2.2 Special Requirements ......................................................................................................... 4 3.0 Offsite Analysis .............................................................................................................................. 5 3.1 Upstream Tributary Area ..................................................................................................... 5 3.2 Downstream Analysis.......................................................................................................... 5 4.0 Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design ............................................................................................................................................. 7 4.1 Flow Control ........................................................................................................................ 7 5.0 Conveyance System Analysis and Design .................................................................................. 9 6.0 Special Reports and Studies ...................................................................................................... 10 7.0 Other Permits ............................................................................................................................... 10 8.0 CSWPP Plan Analysis and Design ............................................................................................. 10 8.1 CSWPPP Analysis and Design ......................................................................................... 10 8.2 CSWPPP Maintenance ..................................................................................................... 10 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant ..................................... 11 10.0 Operations and Maintenance Manual ........................................................................................ 11 11.0 Conclusion .................................................................................................................................... 11 Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Appendices Appendix A General Exhibits A-1 ............. Vicinity Map A-2 ............. Existing Basin Map A-3 ............. Proposed Basin Map A-4 ............. City of Federal Way SWM Asset Atlas Map A-5 ............. Flow Control Applications Map A-6 ............. Flood Insurance Rate Map No. 53033C1235G A-7 ............. King County iMap (Wetlands, Landslide Hazard) A-8 ............. NRCS Soil Map A-9 ............. King County iMap (Drainage Complaints) A-10 ........... City of Federal Way Critical Areas Map A-11 ........... Offsite Analysis Drainage Table A-12 ........... King County iMap (Migrating Rivers) A-13 ........... DOE Water Quality Assessment Map A-14 ........... Filterra Guidelines A-15 ........... Filterra Operation and Maintenance Guide A-16 ........... Water Quality Drainage Map Appendix B Calculations B-1 ............. WWHM Flow Control Calculations B-2 ............. WWHM Water Quality Treatment Calculations B-3 ............. Conveyance System Analysis and Design (to be provided with Final TIR) Appendix C Special Reports C-1............. Geotechnical Engineering Report by Migizi Group, Inc., June 15, 2023 Appendix D Worksheets (to be provided with Final TIR) D-1............. TIR Worksheet D-2............. Operations and Maintenance Manual D-3............. Bond Quantity Worksheet D-4............. Stormwater Facility Summary Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 1 2200572.12 1.0 Project Overview 1.1 Purpose and Scope This Preliminary Technical Information Report (TIR) addresses the design of the stormwater system to be constructed for the redevelopment project located in Federal Way, Washington. This report has been prepared to support the design and analysis of the stormwater management system for the project. The stormwater system has been designed to meet state and local requirements, as described below: x 2021 King County Surface Water Design Manual (KCSWDM) x City of Federal Way Addendum to the KCSWDM, dated December 12, 2021 1.2 Existing Conditions The site is currently occupied by light industrial and low-density residential uses. The south 4.18 acres is the City Federal Way’s existing Operation and Maintenance Facility, while the remaining 9.36 acres is occupied by single-family homes and associated garages and outbuildings. The site is bordered by 28th Avenue South on the west, South 308th Lane on the north, the Sound Transit Link Light Rail and Interstate 5 on the east, and an apartment complex on the south. The surrounding areas are generally low-density residential, with apartments to the south and public parks to the west. The grades on the site slope from 28th Avenue South in the west down to the Sound Transit ROW in the east. Slopes are generally 1-5% at the west end of the property and 10-15% at the east end. All buildings on the residential properties will be demolished to allow construction of the project. The existing O&M facility will remain in place during construction and be demolished once the new O&M facility is complete. The site contains two onsite stormwater basins. A South Basin includes the existing Operation and Maintenance buildings. A series of catch basins and pipes collects and conveys runoff toward the northeast corner of the Basin where it is discharged toward the adjacent Sound Transit/Interstate 5 right-of-way. A North Basin includes the existing single-family homes and outbuildings. No stormwater systems appear to exist in this area, and overland runoff flows eastward to the Sound Transit/Interstate 5 right-of-way. The western property frontage contains two stormwater basins. The South Offsite Basin includes approximately 280 linear feet of 28th Avenue South right-of-way beginning at the intersection with 312th Street South. This area comprises 0.22 acres that is tributary to the public storm system that conveys runoff southward along 28th Avenue South. The North Offsite Basin covers 1.14 acres of 28th Avenue South right-of-way and 308th Lane at the north side of the property. This area drains to the north along 28th Avenue South via roadside ditches and culverts. Please refer to Appendix A-2 for the Existing Basin Map. 1.3 Developed Conditions The City of Federal Way will construct two main buildings consisting of an office building and a fleet building, along with a series of smaller sheds and out-buildings. The site will be divided into two parts. The main access point will be across from South 311th Street. The portion south of this driveway will be the main maintenance office and will be accessible to the public. The area north of this driveway will be for operations work only. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2 2200572.12 The southern third of the site will include the maintenance office building. This will be a one-story building with access points on the west and east sides. South of the building, there will be a parking lot with 7 stalls, including two ADA stalls. East of the building, there will be a parking lot with approximately 57 stalls, including ADA stalls. Walkways will be provided to the west and east side of the building. The northern portion of the site will be the operations area. There will be a one-story operations fleet building and a series of sheds and out-buildings. Parking will mainly be located north and east of the building and will have approximately 108 stalls. There will also be parking areas for large vehicles and storage areas for large equipment. This area will be fully fenced and not accessible to the public. For grading, generally there will be a downslope of 25% to 33% from 28th Ave S to the west edge of the proposed developed areas. From there, the site will slope downhill at 2-5% to the east end of the parking lots. A slope of 33% will then match the existing grade at the east end of the site. An existing ecology block wall along the southeast property line will remain in place. The City of Federal Way also proposes improvements to 28th Avenue South and South 308th Lane. 28th Avenue South will be widened to include a two-way left turn lane, planter strip, and sidewalk. South 308th Lane will be reconstructed with a sidewalk on one side. 1.4 Drainage Basins The project site is mapped by the City as being located at the eastern edge of the Lower Puget Sound Basin. However, the property drains to the east and thus is tributary to the Lower Green River Basin. King County GIS Center identifies the site as being located within the Green/Duwamish Watershed and the drainage basin as Mill Creek. Refer to Appendix A-5 for the Federal Way Flow Control Applications Map. 1.5 Soil Conditions The NRCS classifies onsite soils as belonging to the Alderwood complex. These soils generally are not conducive to infiltration. A geotechnical investigation was performed for the project site by Migizi Group, Inc. A subgrade evaluation found that infiltration is considered infeasible because native soils are very low-permeability glacial till from ground surface to depths of greater than 20 feet below the surface. The Geotechnical Engineering Report (dated June 15, 2023) is included as Appendix C-1. 2.0 Conditions and Requirements Summary A summary of the conditions and requirements for the project are presented in this section. The Core Requirements (CRs) and Special Requirements (SRs) are from the 2021 KCSWDM. 2.1 Core Requirements 2.1.1 CR 1 – Discharge at the Natural Location Stormwater runoff will continue to discharge at the project’s natural discharge location toward the adjacent Sound Transit/Interstate 5 right-of-way to the east which flows to the Lower Green River Basin. Stormwater that discharges from the project area joins downstream in less than one- quarter mile and is thus considered a single Threshold Discharge Area (TDA) as defined by the KCSWDM. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 3 2200572.12 2.1.2 CR 2 – Offsite Analysis A Level 1 offsite analysis was performed for this project and is included in Section 3.0 of this report. 2.1.3 CR 3 – Flow Control The project is designated by City of Federal Way as being within a Conservation Flow Control area. New stormwater detention facilities are proposed for the new plus replaced impervious surface and new landscaped areas to meet all flow control requirements set forth by the KCSWDM. Refer to Appendix A-3 for the Proposed Basin Map, Appendix A-5 for the Federal Way Flow Control Applications Map, and Section 4.0 below for additional information. 2.1.4 CR 4 – Conveyance System Conveyance facilities will be designed in accordance with the 2021 KCSWDM. Refer to Section 5.0 for details of the conveyance system. 2.1.5 CR 5 – Erosion and Sediment Control The project will incorporate appropriate erosion and sediment control systems to address specific site conditions during construction in accordance with the 2021 KCSWDM. A Construction Stormwater Pollution Prevention Plan (CSWPPP) has been prepared and will be provided with the permit submittal. Because more than 1 acre of the site will be disturbed, a National Pollutant Discharge Elimination System (NPDES) permit is required for this project. 2.1.6 CR 6 – Maintenance and Operations The proposed storm drainage system will be owned, operated, and maintained by the City of Federal Way. An Operations and Maintenance Manual is included in Appendix D. 2.1.7 CR 7 – Financial Guarantees and Liability The City of Federal Way and the contractor will obtain all necessary permits and bonds, prior to the beginning of construction, to ensure financial guarantees are posted to sufficiently cover the cost of correcting, if necessary, incomplete or substandard work. 2.1.8 CR 8 – Water Quality Per the City of Federal Way Water Quality Applications Map and the Addendum to the 2021 KCSWDM, pollution generating impervious surfaces (PGIS) must be treated using the Enhanced Basic Water Quality treatment menu. Stormwater runoff from the new and existing PGIS will be treated using Contech Filterra units and bioretention facilities meeting the design requirements outlined in the 2019 Department of Ecology (DOE) Stormwater Management Manual for Western Washington (SMMWW). The project proposes two Contech Filterra units and three bioretention facilities to provide enhanced water quality treatment for the onsite Basins. Additionally, two bioretention facilities will be provided for treatment of the offsite frontage: one in the northern portion of the site to provide water treatment for South 308th Lane and one along the southern property to provide treatment for the 28th Avenue South right-of-way. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 4 2200572.12 Refer to Appendix A-16 for the Water Quality Drainage Map and to Section 4.1.5 below for additional information regarding water quality treatment. 2.1.9 CR 9 – Flow Control BMPs This project proposes work on a single site and the disturbed area exceeds 22,000 square feet; therefore, for CR 9, it must meet the requirements for Large Lot Best Management Practices (BMPs), as described in Section 1.2.9.2.2 in the KCSWDM. Because of the inability to infiltrate, meeting the LID performance requirement is not feasible. The onsite BMPs required by the City are addressed below: 1. Full dispersion is infeasible for the proposed site because there is inadequate native vegetation on the site. 2. Full infiltration and limited infiltration are considered infeasible because the existing site is underlain by very low-permeability glacial till from ground surface to depths of greater than 20 feet below the surface (refer to the Geotechnical Engineering Report dated June 15, 2023, included as Appendix C-1). 3. Basic dispersion is infeasible because there is inadequate native vegetation on the site and steep slopes greater than 15% exist in the downslope portion of the site. However, dispersion trenches will be installed in the eastern edge of the site to spread concentrated flows. 4. Bioretention is considered infeasible for flow control because the existing site is underlain by very low-permeability glacial till from ground surface to depths of greater than 10 feet below the surface (see Geotechnical Engineering Report by Migizi Group, Inc., included in Appendix C-1). Underdrained bioretention facilities are proposed for water quality treatment and may provide a small level of flow control that has not been quantified. 5. Permeable pavement is considered infeasible because the existing site is underlain by fill and very low-permeability glacial till that is not conducive to infiltration. 2.2 Special Requirements 2.2.1 SR 1 – Other Adopted Area-Specific Requirements No other adopted area-specific requirements are known to apply to the project site. 2.2.2 SR 2 – Floodplain/Floodway Delineation Flood Insurance Rate Map No. 53033C1235G was consulted for this project and did not show any floodplains on the project site (refer to Appendix A-6). 2.2.3 SR 3 – Flood Protection Facilities The project does not contain, will not construct, and is not adjacent to any existing flood protection facilities. 2.2.4 SR 4 – Source Controls Most of the Federal Maintenance Facility vehicle fleet will be stored within a covered maintenance building. Parking lots will have little overnight parking that is located outdoors, reducing surface pollution. Volumetric containers used for food, other waste, or chemicals will not be stored outside the building. The City of Federal Way will maintain general housekeeping procedures for preventing pollution in and around the new building s. Trash and debris will be collected regularly. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 5 2200572.12 2.2.5 SR 5 – Oil Control The project does not fit the definition of a high-use site; therefore, it is not subject to oil control requirements. 3.0 Offsite Analysis 3.1 Upstream Tributary Area The project site is located at a point of local high elevation and no upstream area is tributary to the property. 3.2 Downstream Analysis 3.2.1 Task 1 – Study Area Definition and Maps Stormwater from the project area leaves the site via one discharge location along the east property line. A site visit was performed to investigate drainage patterns downstream of the site. The site visit included an investigation of the existing downstream conveyance system. The downstream analysis also included the City of Federal Way SWM Asset Atlas Map, as well as the project survey data. Discharge will occur along the east property line and enter the existing drainage ditch adjacent to the Sound Transit line currently under construction. This ditch flows to the north toward a Type 1 catch basin located east of the northeast corner of Parcel 0921049315 (2839 S 308th Lane). Flows from this catch basin travel eastward in a 12” pipe below the Sound Transit line and discharge onto an existing rip rap pad in the drainage ditch alongside Interstate 5. Approximately 20 feet east of this point, an existing ±24”-diameter culvert pipe conveys stormwater eastward underneath Interstate 5. AHBL personnel were not able to follow the conveyance system beyond this point, but it appears runoff continues to flow toward the Lower Green River Basin on the east side of Interstate 5. 3.2.2 Task 2 – Resource Review The following resources were reviewed to discover any existing or potential problems in the study area: x The City of Federal Way does not designate the area as a Flood Problem Flow Control Area, as indicated in the City of Federal Way Flow Control Applications Map (Appendix A- 5). x The City of Federal Way Critical Areas Map (Appendix A-10) designates no critical areas, wetlands, or landslide areas present on the project site. x The City of Federal Way SWM Asset Atlas Map is provided in Appendix A-4. x Flood Insurance Rate Map No. 53033C1235G was consulted for this project and did not show any floodplains on the project site. Refer to Appendix A-6 of this report. x The King County iMap for wetland, landslide hazards, and sensitive areas does not indicate any landslide or erosion sensitive areas within the project site. No wetlands or critical Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 6 2200572.12 aquifer recharge areas are mapped in the general vicinity of the project site. The King County iMap is provided in Appendix A-7. x The U.S. Department of Agriculture Natural Resources Conservation Service (NRCS) soil map indicates the soil type as Alderwood gravelly sandy loams. The NRCS soil map is provided in Appendix A-8. x King County Drainage Complaint Records: King County maintains a log of drainage complaints received, which are accessible through their online mapping system, King County iMap. The only listed drainage complaint is dated from 1989, and therefore is not believed to pose any current impacts to the downstream analysis of the project site. A map detailing the drainage complaint locations can found in Appendix A-9. x Road drainage problems associated with the project area are listed in the King County Drainage Complaint Records, as noted above. x Migrating rivers are not located within the vicinity of the site. A King County iMap has been provided detailing the nearest migrating river. A copy of this map can be found in Appendix A-12. x A DOE Water Quality Assessment Map was reviewed, and no impaired water bodies are shown on or near the project site. A copy of the map is provided in Appendix A-13. x King County designated water quality problems per Reference 10 of the KCSWDM: None have been noted at this time. x Adopted stormwater compliance plans by Department of Natural Resources and Parks (DNRP) Water and Land Resources were not available. 3.2.3 Task 3 – Field Inspection Site visits were performed to investigate drainage patterns downstream of the site, as well as onsite and upstream of the site. No existing problems were identified at the time of the site visit. Field inspection of the downstream flow path for this Level 1 analysis found no issues of flooding or other conveyance nuisances that were identified in any of the downstream basins. The downstream flow path generally confirms the flow path that is depicted on the City of Federal Way SWM Asset Atlas Map provided in Appendix A-4. None of the following problems were identified in the field inspection: x Existing/potential constrictions or lack of capacity in the existing drainage system. x Existing/potential downstream drainage problems. x Existing/potential overtopping, scouring, bank sloughing, or sedimentation. x Significant destruction of aquatic habitat or organisms. 3.2.4 Task 4 – Drainage System Description and Problem Descriptions The drainage flow path for the project site includes surface water flow to catch basins, which use closed pipe conveyance systems and open conveyance systems to route stormwater runoff to the existing system within the Sound Transit/Interstate 5 right-of-way. Because the project is not Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 7 2200572.12 increasing flows to this flow path, no problems are expected as a result of this project. An offsite analysis drainage system table is included in Appendix A-11. 4.0 Flow Control, Low Impact Development (LID) and Water Quality Facility Analysis and Design 4.1 Flow Control 4.1.1 Existing Site Hydrology The site contains two offsite stormwater basins. The South Offsite Basin includes the southern 280 feet of 28th Avenue South (0.22 acres) and is tributary to the public storm system that conveys runoff southward along 28th Avenue South. The North Offsite Basin comprises 1.14 acres of 28th Avenue South right-of-way and 308th Lane at the north side of the property. This area drains to the north along 28th Avenue South via roadside ditches and culverts. Federal Way GIS data indicate that a 219-foot culvert crosses below 308th Lane. However, the culvert is damaged and blocked, and it appears that runoff from the east side of 28th Avenue South travels eastward along 308th Lane toward a catch basin at the east side of the 308th Lane cul-de-sac, eventually reaching the Sound Transit/Interstate 5 right-of-way. Runoff from the onsite areas also flows eastward to the Sound Transit/Interstate 5 right-of-way. We have divided the onsite area into two stormwater basins. The South Basin includes Parcels 0921049026, 0921049198, and 0921049250 and are the location of the existing Operation and Maintenance buildings. A series of catch basins and pipes collects and conveys runoff toward the northeast corner of the Basin where it is released undetained toward the adjacent Sound Transit/Interstate 5 right-of-way. The North Basin includes existing single-family homes: Parcels 0921049009, 0921049170, 0921049085, 0921049115, 0921049095, 0921049239, 0921049329, 0921049084, 0921049075, 0921049313, and 0921049314. No stormwater systems appear to exist in this area, and overland runoff flows eastward to the Sound Transit/Interstate 5 right-of- way. There are no known existing water quality treatment facilities or flow control facilities at the project site. Refer to the Existing Basin Map in Appendix A-2 for more information. 4.1.2 Developed Site Hydrology The project will construct flow control facilities to the Conservation Flow Control Level 2 standard per City of Federal Way requirements. Multiple stormwater detention facilities are planned to provide flow control for areas of new plus replaced impervious surfacing. Flow control calculations are provided in Appendix B. Because of the topography, not all stormwater runoff from the onsite impervious area can be directed to the proposed detention facility. Therefore, an area exchange is proposed. Refer to Section 4.1.4 for further information. 4.1.3 Performance Standards The 2021 KCSWDM states that to meet Conservation Flow Control, the project must “match developed discharge durations to predeveloped durations for the range of predeveloped discharge rates from 50% of the 2-year peak flow up to the full 50-year peak flow. Also match developed peak discharge rates to predeveloped peak discharge rates for the 2- and 10-year return periods. Assume historic site conditions as the predeveloped condition.” The treatment goal for facility options in the Basic Water Quality menu is 80 percent removal of total suspended solids (TSS) for a typical rainfall year, assuming typical pollutant concentration in urban runoff. The Enhanced Basic water quality treatment goal is 60 percent reduction of total Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 8 2200572.12 zinc and 30 percent of total copper. The City of Federal Way Addendum to the KCSWDM requires sites to provide water quality treatment for all existing, new, and replaced PGIS once the water quality threshold has been met. The project proposes meeting enhanced water quality treatment via biofiltration facilities and Filterra units for all existing and proposed onsite PGIS. 4.1.4 Flow Control System One new subgrade detention system and two detention ponds are proposed to meet flow control requirements for the onsite Basins. For the North Basin, a Brentwood StormTank® modular system with an area of 15,120 square feet is proposed to meet the Basin’s flow control requirements. This system will be approximately 378-feet long, 40-feet wide, and have a maximum water storage depth of 6.0 feet. The West Basin will utilize a 5-foot deep detention pond with bottom dimensions of 80 feet by 39 feet. The South Basin will utilize a 4.5-foot deep detention pond with bottom dimensions of 204.5 feet by 21.5 feet. One underground detention system is proposed for the North Offsite Basin. This will be a Brentwood StormTank® modular system with an area of 4,408 square feet. This system will be approximately 152-feet long, 29-feet wide, and have a maximum water storage depth of 6.0 feet. Because of topography, not all stormwater runoff from the project areas can be directed to the proposed detention facilities. Therefore, the detention systems will be oversized to mitigate flows from the undetained areas. As allowed by KCSWDM Section 1.2.3.2.G, Page 1-53, a flow control trade will be used to provide detention for an existing area to compensate for the impervious surface that is not collected. Stormwater runoff from the existing driveway north of the site will be collected and conveyed to the proposed detention facility. Refer to Appendix A-3 for the Proposed Basin Map, which details the onsite compensatory areas associated with the developed site drainage flow control trade. Table 1 North Onsite Basin Land Use Total Target Area (ac)* Detained Target Area (ac)* Undetained Target Area (ac)* Detained Non-Target Area (ac)* Impervious Areas 3.994 3.994 - - Landscaping 0.765 1.480 0.715 - Total as modeled 4.759 5.474 0.715 - West Onsite Basin Land Use Total Target Area (ac)* Detained Target Area (ac)* Undetained Target Area (ac)* Detained Non-Target Area (ac)* Impervious Areas 0.673 0.673 - - Landscaping 1.205 1.205 - - Total as modeled 1.878 1.878 - - Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 9 2200572.12 South Onsite Basin Land Use Total Target Area (ac)* Detained Target Area (ac)* Undetained Target Area (ac)* Detained Non-Target Area (ac)* Impervious Areas 1.187 1.187 - - Landscaping 1.965 2.065 0.100 - Total as modeled 3.152 3.252 0.100 - North Offsite Basin Land Use Total Target Area (ac)* Detained Target Area (ac)* Undetained Target Area (ac)* Detained Non-Target Area (ac)* Impervious Areas 0.903 0.903 - - Landscaping 0.145 0.145 - - Total as modeled 1.048 1.048 - - * Target areas are those areas that must comply with flow control requirements for stormwater runoff. Non- target areas are areas that do not need to comply with flow control requirements. Refer to Appendix B for flow control modeling output. 4.1.5 Water Quality Systems The City of Federal Way requires enhanced stormwater runoff treatment for sites with more than 5,000 square feet of new effective PGIS. City of Federal Way requires enhanced treatment for runoff for all existing onsite PGIS once the water quality treatment threshold has been exceeded. Water Quality treatment will be provided via bioretention facilities and Filterra units. The North Onsite Basin will include a Filterra unit east of the main parking lot and a bioretention facility at the southeast corner of the basin. The West Onsite Basin will have a bioretention facility located at the southwest corner of the Basin. The South Onsite Basin will have one Filterra unit at the northeast corner of the Basin, and two bioretention facilities: one east of the visitor parking area and one southeast of the main parking lot. The North Offsite Basin will include two bioretention facilities: one along the south property line, and one near the cul-de-sac portion of 308th Lane. Per the General Use Level Designation (GULD) criteria for the Filterra system, the units must meet the water quality design flow rate, which is the peak 15-minute flow rate, as calculated by the Western Washington Hydrology Model (WWHM). The criterion for the bioretention facilities is that they treat a minimum of 91 percent of the runoff volume entering the facility. All Basins meet the water quality standards set forth by the KCSWDM and City of Federal Way development standards. Water quality calculations are included in Appendix B-2, the Water Quality Drainage Map is provided in Appendix A-16, and the Filterra GULD criteria dated June 2020 is included in Appendix A-14. 5.0 Conveyance System Analysis and Design The proposed onsite conveyance system will consist of a network of catch basins and pipes to direct stormwater runoff in a controlled manner through the new improvements. The system is designed to the standards outlined in Section 1.2.4 of the KCSWDM; therefore, the new pipe has sufficient capacity to convey and contain the 25-year, 15-minute peak flow from the developed onsite and existing offsite tributary areas. Supporting calculations will be provided in Appendix B in a future submittal. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 10 2200572.12 6.0 Special Reports and Studies A Geotechnical Engineering Report by Migizi Group, Inc. dated June 15, 2023, is provided in Appendix C-1. 7.0 Other Permits An NPDES stormwater permit from DOE is necessary for this project because the proposed improvements will disturb more than 1.0 acre. 8.0 CSWPP Plan Analysis and Design The proposed development will comply with guidelines set forth in the 2021 KCSWDM. The plan includes erosion/sedimentation control features designed to prevent sediment-laden runoff from leaving the site or from adversely affecting critical water resources during construction. 8.1 CSWPPP Analysis and Design The erosion potential of the site is influenced by four major factors: soil characteristics, vegetative cover, topography, and climate. Erosion/sedimentation control is achieved by a combination of structural measures, cover measures, and construction practices that are tailored to fit the specific site. An erosion and sediment control plan has been prepared for the contractor’s use during construction and is included with the engineering plan submittal. The following measures will be used to control sedimentation/erosion processes: x Clearing Limits: All areas to remain undisturbed during the construction of the site will be delineated prior to any site clearing or grading. x Cover Measures: Disturbed areas shall be covered per Section D.4.2 of the KCSWDM. x Construction Entrances: A stabilized construction entrance consisting of quarry spalls will be placed at the entrances to the project area and as necessary. x Perimeter Protection: Filter fabric fencing and straw wattles will be provided along the downhill edges of developed areas to protect the sensitive wetland areas and to prevent sediment-laden runoff migration. x Storm Drain Inlet Protection: Filter fabric protection will be provided on all new and existing catch basins downstream of construction activities. x Surface Water Control: Interceptor ditches and/or pipes will be used to direct runoff from construction areas to Baker tanks that will hold sediment laden runoff. x Dust Control: Dust control measures will be implemented when exposed soils are dry to the point that wind transport is possible, and roadways, drainage ways, or surface waters are likely to be impacted. 8.2 CSWPPP Maintenance All erosion and sediment control measures shall be maintained and reviewed on a regular basis, as prescribed by the maintenance requirements of each BMP. Maintenance requirements will be included in Appendix D in the final TIR. Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 11 2200572.12 8.2.1 CSWPPP Supervisor The contractor shall designate a CSWPPP supervisor who shall be responsible for maintenance and review of erosion and sediment control and for compliance with all permit conditions relating to these measures. The CSWPPP supervisor must be available for rapid response to erosion and sediment control problems. 8.2.2 Documentation A standard CSWPPP Maintenance Report will be provided for the contractor’s convenience. A copy of all required maintenance reports shall be kept onsite throughout the duration of construction. 8.2.3 Review Timing During the wet season, weekly reviews shall be carried out in accordance with the NPDES permit and City of Federal Way requirements. 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant The Bond Quantity Worksheet and the Stormwater Facility Summary will be included in Appendix D of the final TIR. 10.0 Operations and Maintenance Manual The drainage facilities detailed in this report will be maintained by the City of Federal Way. Maintenance requirements for the new stormwater facilities will be included in Appendix D of the final TIR. 11.0 Conclusion This site has been designed to meet the requirements of the 2021 KCSWDM, as adopted by the City of Federal Way. The site incorporates detention and water quality facilities to treat stormwater draining from the site and to protect downstream property owners and drainage systems. Hydrologic calculations/modeling used King County standards for sizing stormwater detention, treatment, and conveyance facilities. This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. We conclude that this project will not create any new problems within the downstream drainage system, nor will this project aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. Dan Osier, PE Senior Engineer DJO/lsk December 2023 \\ahbl.com\data\Projects\2020\2200572\10_CIV\NON_CAD\REPORTS\Storm\20231109 Rpt (TIR) 2200572.12.docx Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Appendix A General Exhibits A-1 .................... Vicinity Map A-2 .................... Existing Basin Map A-3 .................... Proposed Basin Map A-4 .................... City of Federal Way SWM Asset Atlas Map A-5 .................... Flow Control Applications Map A-6 .................... Flood Insurance Rate Map No. 53033C1235G A-7 .................... King County iMap (Wetlands, Landslide Hazard) A-8 .................... NRCS Soil Map A-9 .................... King County iMap (Drainage Complaints) A-10 .................. City of Federal Way Critical Areas Map A-11 .................. Offsite Analysis Drainage Table A-12 .................. King County iMap (Migrating Rivers) A-13 .................. DOE Water Quality Assessment Map A-14 .................. Filterra Guidelines A-15 .................. Filterra Operation and Maintenance Guide A-16 .................. Water Quality Drainage Map DRAWN BY: DATE: JOB NO.: 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX N 0 100 2001" = 100 FEETGRAPHIC SCALE500 N 0 100 2001" = 100 FEETGRAPHIC SCALE500 FifMiltonTacomaDesMoinesEdgewoodPacificAuburnFederalWayKentHylebos Creek WaterwayBlair WaterwayPuyallu p R iv e rPuget SoundBayDumasPovertyBaySitcum Water way CommencementBayLakeSteelStarLakeMirrorLakeGenevaLakeNorthLakeLorene LakeJeaneLakeEasterLakeDolloff Lak e TroutLakeFiveMileLakeLake KillarneyHO Y T R D S W MILITARY RD SWESTVALLEYS 288th STDASH POINT RDDASH PT RDMILITARY RD S21st AVE SWPACIFIC HWYMARINE VIEW D R SW 336th STNORTHSHORE PKWYINTERSTATE 5E 11th STHWY 18HWY 18PACIFIC HWY S28TH AVE SENCH A N T E D P K W Y51st AVE SINTERSTATE 51st AVE SPACIFIC HWY SS 320th ST21st AVE SWS 336th ST1st AVE SS 312th STSW 320th STSW 356th STS 348th STSS 272nd ST33rd ST NELower PugetSound BasinHylebosCreekBasinMillCreekBasinLowerGreenRiverBasin00.510.25 MileThis map is intended for use as a graphical representation only. The City of Federal Way makes no warranty as to its accuracy.LegendDrainage Basin BoundaryStreamsCity LimitsLakes and WetlandsScale:City of Federal WayFlow ControlApplications MapMap Date: February, 2010SWM DivisionCity of Federal Way33325 8th Ave SPO Box 9718Federal Way, WA 98063(253) 835-2700www.cityoffederalway.comR:\erike\swm\FlowControl\flowcontrol.mxdFlow ControlBasic Flow Control AreasConservation Flow Control AreasFlood Problem Flow Control AreasMajor Receiving Waters1. Puget SoundA-5 King County iMapDate: 8/17/2017 Notes:±The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout 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 survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.LegendPotentiallandslide hazardareas (2016, seeexplanation--->)Potentiallandslide hazardareas 50-footbuffer (2016)Landslidehazards,incorporated KC(1990)Potential steepslope hazardareas (2016, seeexplanation--->)Landslidehazard (1990SAO)Erosion hazard(1990 SAO)Seismic hazard(1990 SAO)Coal minehazard (1990SAO)class 1class 2 perennialclass 2 salmonidclass 3unclassifiedWetland (1990SAO)Sensitive areanotice on titleChinookdistribution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$FURVVVORSHVKDSH&RQFDYH +\GULFVRLOUDWLQJ<HV 1RUPD 3HUFHQWRIPDSXQLWSHUFHQW /DQGIRUP'UDLQDJHZD\VGHSUHVVLRQV /DQGIRUPSRVLWLRQWKUHHGLPHQVLRQDO'LS 'RZQVORSHVKDSH/LQHDUFRQFDYH $FURVVVORSHVKDSH&RQFDYH +\GULFVRLOUDWLQJ<HV &XVWRP6RLO5HVRXUFH5HSRUW King County Date: 11/15/2023 The information included on this map has been compiled by King County staff from a variety of sources and is subject to change 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 survey product. 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 Stormwater facilities Bonded Commercial-MF Commercial-SF Construction DOT FMD Regional Residential Drainage complaints Map King County iMap ± Critical Areas!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!SW 312th St SW 320th St IP o r t o f T a c o m a R dMar i neVi e wDr Northshore Pkw y Mi lit a r y Rd S 28th Av SEnchanted PkwyMilitary Rd SP e asl eyCanyonRdRedondoWySR edo n d o B each DrSPacInterstate 5StarLak e R d 1stWySS 324th St E 11th StInterstate5SW Da s h P oi nt R d SW D a s h P o in tR d NE 49th St10thAvSWSW Campus Dr S WCampus Dr S 336th St Pacific Hwy SSW 330th St SW 356th St NorpointWyNES 356th St Pacific Hwy SS 356thSt Hwy 18WeyerhaeuserWySSDash P o in tR d 1st Av SS 304th St Mi l i taryRdS S 288th St Military Rd SS 288th St S 272nd St y SS 312th St I nt erst ate5Military Rd SS 272nd St Pacific Hwy S16th Av SM arine Vie w D r Enchanted PkwyMilitaryRd1st Av S9thAvS21st Av SW23rd Av S16thAvSHwy 18S 348th St S 308th St PacificHwySMilitaryRdSSW 340th StHoyt R d S W SW 336th St 21st Av SWH o yt R d SWSW 320th St SW 308th St SW Dash Point RdSWDa s h Point Rd 35th Av SW47th Av SW12th Av SW21st Av SW11th Av SW8th Av SWS 3 2 8 t h S t 5th Av SS 336th St 7th Av6thAv8thAv6th Av SWSW 344th St 28th Av S20th Av SS 373rd St 34th Av SS 298th St 37th Av SS304th St 31stAvSS 320th St20th Av SS 312th St Pacific Hwy SS 320th St 11th Pl S1st Av S8th Av SPavillions Center Celebration Center SeaTac Village Pal-do World Plaza The Commons at Federal Way Gateway Center Twin LakesVillage Campus Square Federal Way Marketplace Federal Way Crossings Lakehaven Treatment Center (Redondo) Lakehaven Treatment Center (Lakota)Lake Grove Elem. Lake Dolloff Elem. Lakeland Elem Valhalla Elem. Silver Lake Elem. Wildwood Elem. Brigadoon Elem. Twin Lakes Elem. Adelaide Elem. Sherwood Forest Elem. Panther Lake Elem. Camelot Elem. Nautilus Elem. Mark Twain Elem. Rainier View Elem. Olympic View Elem.Green Gables Elem. Enterprise Elem. Mirror Lake Elem. Star Lake Elem. Illahee Middle School Lakota Middle School Sacajawea Middle School Kilo Middle School Totem Middle School Saghalie Middle School Sequoyah Middle School Public Academy Decatur High School Federal Way High School Thomas Jefferson High School Todd Beamer High School Truman H.S. Golf Golf Twin Course Course Lakes Northshore Golf Course Star Lake Park & Ride Federal Way/ S 320th Street Park & Ride Twin Lakes Park & Ride South Federal Way Park & Ride Redondo Heights Park & Ride Transit Center Dumas Bay Centre & Federal Way Community Center Knutzen Theater Steel Lake Annex City Hall Steel Lake Park Celebration Lakota Sacajawea Park FrenchParkLake Park Park Dumas Bay Park Adelaide Park Camelot Park Dash PointState Park SaghaliePark Lake Geneva Park Glen Nelson Park West Hylebos Wetlands Park Five Mile Lake Park Bingaman Pond Park B.P.A. Trail B.P.A. TrailWestCampus TrailB.P.A.TrailLaurelwood Park Spring Valley Open Space Fisher's Pond Panther Lake Open Space Park Poverty Bay Open Space Pacific RimBonsai Collection Rhododendron Species Botanical Garden Enchanted Park Pie r c e C o u n t y Ki n g C o u n t y Pie r c e C o u n t y King County Pierce County King County Pierce County Ki n g C o u n t y Fire Station 65 Fire Station 61 Fire Station 64 Fire Station 63 Training Center Fire Station 62 Fire Station 66 Federal Way Regional Library 320th Street Library Fife Milton Tacoma Des Moines Edgewood Pa Auburn Federal Way Kent H y l e b o s C r e e k W a t e r w a y Bl a i r W a t e r w a yRiv erPuget Sound BayDumas PovertyBay mWat e rway Commencement Bay Lake Steel Star Lake MirrorLake Geneva Lake North Lake Lorene Lake Jeane Lake Easter Lake Dollo ff LakeTrout Lake Five Mile LakeLakeKillarney 161 99 !"#$5 99 !"#$5 !"#$5 509 18 509 509 161 99 509 509 White River Mill Creek Hylebos Creek Lower Puget Sound Lower Green River Hylebos Creek Lower Puget Sound 5 City of Federal Way Critical Areas Map Map Date: September, 2012 City of Federal Way, GIS Division 33325 8th Ave S Federal Way, WA 98003 (253) 835-7000 www.cityoffederalway.com ´ This map is accompanied by NO warranties, and is simply a graphic representation.J:\standard\reference\sensitive.mxd King County Vicinity MapHylebos Creek Lower Green River Lower Puget Sound Mill Creek White River Erosion Hazard Area Landslide Hazard Areas Wetlands (1998 City Survey) Lakes Streams Drainage Basins:Critical Areas:Water Features: Legend: Boundaries are approximate. Remember, ADDITIONAL SENSITIVE AREAS MAY EXIST. See Map Notes below for more information.Please Note:Map Notes: Wetlands and streams were identified in a 1998 City of Federal Way survey. Data for the Landslide hazard and erosion hazard areas is provided by King County. Drainage basin boundaries within city limits have been verified by the City of Federal Way. Basin boundaries outside of city limits are provided by King County and have not been verified by the City of Federal Way. Critical area information is provided for illustrative purposes ONLY. Actual boundaries are subject of field verification. ADDITIONAL CRITICAL AREAS MAY EXIST. Critical areas in Pierce County are not shown. The City of Federal Way shall not be liable for any damages due to the use or misuse of the information represented on this map. Wetlands are only shown in Federal Way and its Potential Annexation Area. Contact the City for an explanation of these areas and the regulations that govern them. Source: City of Federal Way, King County 00.510.25 Miles Scale: 50 Acres 5 20 47°15'5.46831"N122°25'3.78156"W47°21'46.42899"N 122°25'3.78156"W47°21'46.42899"N 122°16'19.25508"W47°15'5.46831"N 122°16'19.25508"WA B C D E F A B C D E F 1 2 3 4 5 6 7 1 2 3 4 5 6 7 A-10 Off-site Anal ysis Drainage System Table King County Surface Water Design Manual, Core Requirement #2Basin: Subbasin SubbasinDateName:Number:Symbol Drainage Component Type, Name, and SizeDrainageComponentDescriptionSlope Distance from site dischargeExistingProblemsPotentialProblemsObservations of field inspector, resource reviewer, or residentsee mapType: sheet flow, swale, stream, channel, pipe, pond, flow control/wq BMP; Size: diameter, surface areadrainage basin, vegetation, cover, depth, type of sensitive area, volume% % ml = 1,320 ft.constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosiontributary area, likelihood of problem, overflow pathways, potential impacts2021 Draft Surface Water Design ManualLast revised 4/24/201611/22/20232A2B2C2D12" PipeDitchSound TransitSound Transit750 Feet790 Feet810 FeetUnknown1.0%5.0%0.5%UnknownNoneNoneNoneNone knownNoneNoneNoneNone knownNoneNoneNoneNoneSee Ex. A-4±24" PipeTDA 2Interstate 5Interstate 5Lower Green River BasinSouth OffsiteDitch King County iMapDate: 9/11/2017 Notes:±The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout 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 survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.LegendseveremoderateA-12 Water Quality Assesment MapSources: Esri, HERE, DeLorme, Intermap, increment P Corp., GEBCO,USGS, FAO, NPS, NRCAN, GeoBase, IGN, Kadaster NL, Ordnance Survey,Esri Japan, METI, Esri China (Hong Kong), swisstopo, MapmyIndia, ©September 11, 20170241MilesKAssessedWaters/SedimentWaterCategory 5 - 303dCategory 4CCategory 4BCategory 4ACategory 2Category 1SedimentCategory 5 - 303dCategory 4CCategory 4BCategory 4ACategory 2Category 1A-13 1 June 2020 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS), ENHANCED, PHOSPHORUS & OIL TREATMENT For CONTECH Engineered Solutions Filterra® Ecology’s Decision: Based on Contech’s submissions, including the Final Technical Evaluation Reports, dated August 2019, March 2014, December 2009, and additional information provided to Ecology dated October 9, 2009, Ecology hereby issues the following use level designations: 1. A General Use Level Designation for Basic, Enhanced, Phosphorus, and Oil Treatment for the Filterra® system constructed with a minimum media thickness of 21 inches (1.75 feet), at the following water quality design hydraulic loading rates: Treatment Infiltration Rate (in/hr) for use in Sizing Basic 175 Phosphorus 100 Oil 50 Enhanced 175 2. The Filterra is not appropriate for oil spill-control purposes. 3. Ecology approves Filterra systems for treatment at the hydraulic loading rates listed above, and sized based on the water quality design flow rate for an off-line system. Calculate the water quality design flow rates using the following procedures: x Western Washington: for treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology-approved continuous runoff model. x Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three flow rate based methods described in Chapter 2.7.6 of the Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual. x Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. 2 4. This General Use Level Designation has no expiration date, but Ecology may revoke or amend the designation, and is subject to the conditions specified below. Ecology’s Conditions of Use: Filterra systems shall comply with these conditions shall comply with the following conditions: 1. Design, assemble, install, operate, and maintain the Filterra systems in accordance with applicable Contech Filterra manuals and this Ecology Decision. 2. The minimum size filter surface-area for use in Washington is determined by using the design water quality flow rate (as determined in this Ecology Decision, Item 3, above) and the Infiltration Rate from the table above (use the lowest applicable Infiltration Rate depending on the level of treatment required). Calculate the required area by dividing the water quality design flow rate (cu-ft/sec) by the Infiltration Rate (converted to ft/sec) to obtain required surface area (sq-ft) of the Filterra unit. 3. Each site plan must undergo Contech Filterra review before Ecology can approve the unit for site installation. This will ensure that design parameters including site grading and slope are appropriate for use of a Filterra unit. 4. Filterra media shall conform to the specifications submitted to and approved by Ecology and shall be sourced from Contech Engineered Solutions, LLC with no substitutions. 5. Maintenance includes removing trash, degraded mulch, and accumulated debris from the filter surface and replacing the mulch layer. Use inspections to determine the site-specific maintenance schedules and requirements. Follow maintenance procedures given in the most recent version of the Filterra Operation and Maintenance Manual. 6. Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a particular model/size of manufactured treatment device. x Contech designs Filterra systems for a target maintenance interval of 6 months in the Pacific Northwest. Maintenance includes removing and replacing the mulch layer above the media along with accumulated sediment, trash, and captured organic materials therein, evaluating plant health, and pruning the plant if deemed necessary. x Conduct maintenance following manufacturer’s guidelines. 7. Filterra systems come in standard sizes. 8. Install the Filterra in such a manner that flows exceeding the maximum Filterra operating rate are conveyed around the Filterra mulch and media and will not resuspend captured sediment. 9. Discharges from the Filterra units shall not cause or contribute to water quality standards violations in receiving waters. 3 Approved Alternate Configurations Filterra Internal Bypass - Pipe (FTIB-P) 1. The Filterra® Internal Bypass – Pipe allows for piped-in flow from area drains, grated inlets, trench drains, and/or roof drains. Design capture flows and peak flows enter the structure through an internal slotted pipe. Filterra® inverted the slotted pipe to allow design flows to drop through to a series of splash plates that then disperse the design flows over the top surface of the Filterra® planter area. Higher flows continue to bypass the slotted pipe and convey out the structure. 2. To select a FTIB-P unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterra Internal Bypass – Curb (FTIB-C) 1. The Filterra® Internal Bypass –Curb model (FTIB-C) incorporates a curb inlet, biofiltration treatment chamber, and internal high flow bypass in one single structure. Filterra® designed the FTIB-C model for use in a “Sag” or “Sump” condition and will accept flows from both directions along a gutter line. An internal flume tray weir component directs treatment flows entering the unit through the curb inlet to the biofiltration treatment chamber. Flows in excess of the water quality treatment flow rise above the flume tray weir and discharge through a standpipe orifice; providing bypass of untreated peak flows. Americast manufactures the FTIB-C model in a variety of sizes and configurations and you may use the unit on a continuous grade when a single structure providing both treatment and high flow bypass is preferred. The FTIB-C model can also incorporate a separate junction box chamber to allow larger diameter discharge pipe connections to the structure. 2. To select a FTIB-C unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterra® Shallow 1. The Filterra Shallow provides additional flexibility for design engineers and designers in situations where various elevation constraints prevent application of a standard Filterra configuration. Engineers can design this system up to six inches shallower than any of the previous Filterra unit configurations noted above. 2. Ecology requires that the Filterra Shallow provide a media contact time equivalent to that of the standard unit. This means that with a smaller depth of media, the surface area must increase. 3. To select a Filterra Shallow System unit, the designer must first identify the size of the standard unit using the modeling guidance described above. 4. Once the size of the standard Filterra unit is established using the sizing technique described above, use information from the following table to select the appropriate size Filterra Shallow System unit. 4 Shallow Unit Basic, Enhanced, Phosphorus, and Oil Treatment Sizing Standard Depth Equivalent Shallow Depth 4x4 4x6 or 6x4 4x6 or 6x4 6x6 4x8 or 8x4 6x8 or 8x6 6x6 6x10 or 10x6 6x8 or 8x6 6x12 or 12x6 6x10 or 10x6 13x7 Notes: 1. Shallow Depth Boxes are less than the standard depth of 3.5 feet but no less than 3.0 feet deep (TC to INV). Applicant: Contech Engineered Solutions, LLC. Applicant’s Address: 11815 NE Glenn Widing Drive Portland, OR 97220 Application Documents: y State of Washington Department of Ecology Application for Conditional Use Designation, Americast (September 2006) y Quality Assurance Project Plan Filterra® Bioretention Filtration System Performance Monitoring, Americast (April 2008) y Quality Assurance Project Plan Addendum Filterra® Bioretention Filtration System Performance Monitoring, Americast (June 2008) y Draft Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (August 2009) y Final Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (December 2009) y Technical Evaluation Report Appendices Filterra® Bioretention Filtration System Performance Monitoring, Americast, (August 2009) y Memorandum to Department of Ecology Dated October 9, 2009 from Americast, Inc. and Herrera Environmental Consultants y Quality Assurance Project Plan Filterra® Bioretention System Phosphorus treatment and Supplemental Basic and Enhanced Treatment Performance Monitoring, Americast (November 2011) y Filterra® letter August 24, 2012 regarding sizing for the Filterra® Shallow System. y University of Virginia Engineering Department Memo by Joanna Crowe Curran, Ph. D dated March 16, 2013 concerning capacity analysis of Filterra® internal weir inlet tray. y Terraphase Engineering letter to Jodi Mills, P.E. dated April 2, 2013 regarding Terraflume Hydraulic Test, Filterra® Bioretention System and attachments. y Technical Evaluation Report, Filterra® System Phosphorus Treatment and Supplemental Basic Treatment Performance Monitoring. March 27th, 2014. y State of Washington Department of Ecology Application for Conditional Use Level Designation, Contech Engineered Solutions (May 2015) 5 y Quality Assurance Project Plan Filterra® Bioretention System, Contech Engineered Solutions (May 2015) y Filterra Bioretention System Armco Avenue General Use Level Designation Technical Evaluation Report, Contech Engineered Solutions (August 2019) Applicant’s Use Level Request: General Level Use Designation for Basic (175 in/hr), Enhanced (175 in/hr), Phosphorus (100 in/hr), and Oil Treatment (50 in/hr). Applicant’s Performance Claims: Field-testing and laboratory testing show that the Filterra® unit is promising as a stormwater treatment best management practice and can meet Ecology’s performance goals for basic, enhanced, phosphorus, and oil treatment. Findings of Fact: Field Testing 2015-2019 1. Contech completed field testing of a 4 ft. x 4 ft. Filterra® unit at one site in Hillsboro, Oregon from September 2015 to July 2019. Throughout the monitoring period a total of 24 individual storm events were sampled, of which 23 qualified for TAPE sampling criteria. 2. Contech encountered several unanticipated events and challenges that prevented them from collecting continuous flow and rainfall data. An analysis of the flow data from the sampled events, including both the qualifying and non-qualifying events, demonstrated the system treated over 99 % of the influent flows. Peak flows during these events ranged from 25 % to 250 % of the design flow rate of 29 gallons per minute. 3. Of the 23 TAPE qualified sample events, 13 met requirements for TSS analysis. Influent concentrations ranged from 20.8 mg/L to 83 mg/L, with a mean concentration of 46.3 mg/L. The UCL95 mean effluent concentration was 15.9 mg/L, meeting the 20 mg/L performance goal for Basic Treatment. 4. All 23 TAPE qualified sample events met requirements for dissolved zinc analysis. Influent concentrations range from 0.0384 mg/L to 0.2680 mg/L, with a mean concentration of 0.0807 mg/L. The LCL 95 mean percent removal was 62.9 %, meeting the 60 % performance goal for Enhanced Treatment. 5. Thirteen of the 23 TAPE qualified sample events met requirements for dissolved copper analysis. Influent concentrations ranged from 0.00543 mg/L to 0.01660 mg/L, with a mean concentration of 0.0103 mg/L. The LCL 95 mean percent removal was 41.2 %, meeting the 30 % performance goal for Enhanced Treatment. 6. Total zinc concentrations were analyzed for all 24 sample events. Influent EMCs for total zinc ranged from 0.048 mg/L to 5.290 mg/L with a median of 0.162 mg/L. Corresponding effluent EMCs for total zinc ranged from 0.015 mg/L to 0.067 mg/L with a median of 6 0.029 mg/L. Total event loadings for the study for total zinc were 316.85 g at the influent and 12.92 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 95.9 %. 7. Total copper concentrations were analyzed for all 24 sample events. Influent EMCs for total copper ranged from 0.003 mg/L to 35.600 mg/L with a median value of 0.043 mg/L. Corresponding effluent EMCs for total copper ranged from 0.002 mg/L to 0.015 mg/L with a median of 0.004 mg/L. Total event loadings for total copper for the study were 1,810.06 g at the influent and 1.90 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 99.9 %. Field Testing 2013 1. Filterra completed field-testing of a 6.5 ft x 4 ft. unit at one site in Bellingham, Washington. Continuous flow and rainfall data collected from January 1, 2013 through July 23, 2013 indicated that 59 storm events occurred. Water quality data was obtained from 22 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 2. The system treated 98.9 % of the total 8-month runoff volume during the testing period. Consequently, the system achieved the goal of treating 91 % of the volume from the site. Stormwater runoff bypassed Filterra treatment during four of the 59 storm events. 3. Of the 22 sampled events, 18 qualified for TSS analysis (influent TSS concentrations ranged from 25 to 138 mg/L). The data were segregated into sample pairs with influent concentration greater than and less than 100 mg/L. The UCL95 mean effluent concentration for the data with influent less than 100 mg/L was 5.2 mg/L, below the 20- mg/L threshold. Although the TAPE guidelines do not require an evaluation of TSS removal efficiency for influent concentrations below 100 mg/L, the mean TSS removal for these samples was 90.1 %. Average removal of influent TSS concentrations greater than 100 mg/L (three events) was 85 %. In addition, the system consistently exhibited TSS removal greater than 80 % at flow rates equivalent to a 100 in/hr infiltration rate and was observed at 150 in/hr. 4. Ten of the 22 sampled events qualified for TP analysis. Americast augmented the dataset using two sample pairs from previous monitoring at the site. Influent TP concentrations ranged from 0.11 to 0.52 mg/L. The mean TP removal for these twelve events was 72.6 %. The LCL95 mean percent removal was 66.0, well above the TAPE requirement of 50 %. Treatment above 50 % was evident at 100 in/hr infiltration rate and as high as 150 in/hr. Consequently, the Filterra test system met the TAPE Phosphorus Treatment goal at 100 in/hr. Influent ortho-P concentrations ranged from 0.005 to 0.012 mg/L; effluent ortho-P concentrations ranged from 0.005 to 0.013 mg/L. The reporting limit/resolution for the ortho-P test method is 0.01 mg/L, therefore the influent and effluent ortho-P concentrations were both at and near non-detect concentrations. 7 Field Testing 2008-2009 1. Filterra completed field-testing at two sites at the Port of Tacoma. Continuous flow and rainfall data collected during the 2008-2009 monitoring period indicated that 89 storm events occurred. The monitoring obtained water quality data from 27 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 2. During the testing at the Port of Tacoma, 98.96 to 99.89 % of the annual influent runoff volume passed through the POT1 and POT2 test systems respectively. Stormwater runoff bypassed the POT1 test system during nine storm events and bypassed the POT2 test system during one storm event. Bypass volumes ranged from 0.13 % to 15.3% of the influent storm volume. Both test systems achieved the 91 % water quality treatment-goal over the 1-year monitoring period. 3. Consultants observed infiltration rates as high as 133 in/hr during the various storms. Filterra did not provide any paired data that identified percent removal of TSS, metals, oil, or phosphorus at an instantaneous observed flow rate. 4. The maximum storm average hydraulic loading rate associated with water quality data is <40 in/hr, with the majority of flow rates < 25 in/hr. The average instantaneous hydraulic loading rate ranged from 8.6 to 53 in/hr. 5. The field data showed a removal rate greater than 80 % for TSS with an influent concentration greater than 20 mg/L at an average instantaneous hydraulic loading rate up to 53 in/hr (average influent concentration of 28.8 mg/L, average effluent concentration of 4.3 mg/L). 6. The field data showed a removal rate generally greater than 54 % for dissolved zinc at an average instantaneous hydraulic loading rate up to 60 in/hr and an average influent concentration of 0.266 mg/L (average effluent concentration of 0.115 mg/L). 7. The field data showed a removal rate generally greater than 40 % for dissolved copper at an average instantaneous hydraulic loading rate up to 35 in/hr and an average influent concentration of 0.0070 mg/L (average effluent concentration of 0.0036 mg/L). 8. The field data showed an average removal rate of 93 % for total petroleum hydrocarbon (TPH) at an average instantaneous hydraulic loading rate up to 53 in/hr and an average influent concentration of 52 mg/L (average effluent concentration of 2.3 mg/L). The data also shows achievement of less than 15 mg/L TPH for grab samples. Filterra provided limited visible sheen data due to access limitations at the outlet monitoring location. 9. The field data showed low percentage removals of total phosphorus at all storm flows at an average influent concentration of 0.189 mg/L (average effluent concentration of 0.171 mg/L). We may relate the relatively poor treatment performance of the Filterra system at this location to influent characteristics for total phosphorus that are unique to the Port of Tacoma site. It appears that the Filterra system will not meet the 50 % removal performance goal when the majority of phosphorus in the runoff is expected to be in the dissolved form. 8 Laboratory Testing 1. Filterra performed laboratory testing on a scaled down version of the Filterra unit. The lab data showed an average removal from 83-91 % for TSS with influents ranging from 21 to 320 mg/L, 82-84 % for total copper with influents ranging from 0.94 to 2.3 mg/L, and 50-61 % for orthophosphate with influents ranging from 2.46 to 14.37 mg/L. 2. Filterra conducted permeability tests on the soil media. 3. Lab scale testing using Sil-Co-Sil 106 showed removals ranging from 70.1 % to 95.5 % with a median removal of 90.7 %, for influent concentrations ranging from 8.3 to 260 mg/L. Filterra ran these laboratory tests at an infiltration rate of 50 in/hr. 4. Supplemental lab testing conducted in September 2009 using Sil-Co-Sil 106 showed an average removal of 90.6 %. These laboratory tests were run at infiltration rates ranging from 25 to 150 in/hr for influent concentrations ranging from 41.6 to 252.5 mg/L. Regression analysis results indicate that the Filterra system’s TSS removal performance is independent of influent concentration in the concentration rage evaluated at hydraulic loading rates of up to 150 in/hr. Contact Information: Applicant: Jeremiah Lehman Contech Engineered Solutions, LLC. 11815 Glenn Widing Dr Portland, OR 97220 (503) 258-3136 jlehman@conteches.com Applicant’s Website: http://www.conteches.com Ecology web link: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 407-6444 douglas.howie@ecy.wa.gov Date Revision December 2009 GULD for Basic, Enhanced, and Oil granted, CULD for Phosphorus September 2011 Extended CULD for Phosphorus Treatment September 2012 Revised design storm discussion, added Shallow System. January 2013 Revised format to match Ecology standards, changed Filterra contact information February 2013 Added FTIB-P system March 2013 Added FTIB-C system April 2013 Modified requirements for identifying appropriate size of unit 9 June 2013 Modified description of FTIB-C alternate configuration March 2014 GULD awarded for Phosphorus Treatment. GULD updated for a higher flow-rate for Basic Treatment. June 2014 Revised sizing calculation methods March 2015 Revised Contact Information June 2015 CULD for Basic and Enhanced at 100 in/hr infiltration rate September 2019 GULD for Basic and Enhanced at 175 in/hr infiltration rate February 2020 Revised sizing language to note sizing based on off-line calculations June 2020 Added Phosphorus to Filterra Shallow sizing table Filterra Owner’s Manual ® Bioretention Systems ENGINEERED SOLUTIONS A-15 A-15 www.ContechES.com/filterra | 800-338-1122 3 Table of Contents Introduction ................................................................................4 Activation Overview .....................................................................4 Filterra Plant Selection Overview ...................................................6 Warranty Overview ......................................................................6 Routine Maintenance Guidelines...................................................6 Maintenance Visit Procedure .........................................................9 Appendix 1 – Activation Checklist ...............................................12 Appendix 2 – Planting Requirements for Filterra Systems ................13 Enclosed Local Area Filterra Plant List ® Bioretention Systems ENGINEERED SOLUTIONS A-15 www.ContechES.com/filterra | 800-338-11224 Introduction Thank you for your purchase of the Filterra® Bioretention System. Filterra is a specially engineered stormwater treatment system incorporating high performance biofiltration media to remove pollutants from stormwater runoff. The system’s biota (vegetation and soil microorganisms) then further breakdown and absorb captured pollutants. All components of the system work together to provide a sustainable long-term solution for treating stormwater runoff. The Filterra system has been delivered to you with protection in place to resist intrusion of construction related sediment which can contaminate the biofiltration media and result in inadequate system performance. These protection devices are intended as a best practice and cannot fully prevent contamination. It is the purchaser’s responsibility to provide adequate measures to prevent construction related runoff from entering the Filterra system. Included with your purchase is Activation of the Filterra system by the manufacturer as well as a 1-year warranty from delivery of the system and 1-year of routine maintenance (mulch replacement, debris removal, and pruning of vegetation) up to twice during the first year after activation. Design and Installation Each project presents different scopes for the use of Filterra systems. Information and help may be provided to the design engineer during the planning process. Correct Filterra box sizing (by rainfall region) is essential to predict pollutant removal rates for a given area. The engineer shall submit calculations for approval by the local jurisdiction. The contractor is responsible for the correct installation of Filterra units as shown in approved plans. A comprehensive installation manual is available at www.ContechES.com. Activation Overview Activation of the Filterra system is a procedure completed by the manufacturer to place the system into working condition. This involves the following items: • Removal of construction runoff protection devices • Planting of the system’s vegetation • Placement of pretreatment mulch layer using mulch certified for use in Filterra systems. Activation MUST be provided by the manufacturer to ensure proper site conditions are met for Activation, proper installation of the vegetation, and use of pretreatment mulch certified for use in Filterra systems. A-15 www.ContechES.com/filterra | 800-338-1122 5 Minimum Requirements The minimum requirements for Filterra Activation are as follows: 1.The site landscaping must be fully stabilized, i.e. full landscaping installed and some grass cover (not just straw and seed) is required to reduce sediment transport. Construction debris and materials should be removed from surrounding area. 2.Final paving must be completed. Final paving ensures that paving materials will not enter and contaminate the Filterra system during the paving process, and that the plant will receive runoff from the drainage area, assisting with plant survival for the Filterra system. 3.Filterra throat opening should be at least 4” in order to ensure adequate capacity for inflow and debris. An Activation Checklist is included on page 12 to ensure proper conditions are met for Contech to perform the Activation services. A charge of $500.00 will be invoiced for each Activation visit requested by Customer where Contech determines that the site does not meet the conditions required for Activation. A-15 www.ContechES.com/filterra | 800-338-11226 Filterra Plant Selection Overview A Plant List has been enclosed with this packet highlighting recommended plants for Filterra systems in your area. Keep in mind that plants are subject to availability due to seasonality and required minimum size for the Filterra system. Plants installed in the Filterra system are container plants (max 15 gallon) from nursery stock and will be immature in height and spread at Activation. It is the responsibility of the owner to provide adequate irrigation when necessary to the plant of the Filterra system. The “Planting Requirements for Filterra Systems” document is included as an appendix and discusses proper selection and care of the plants within Filterra systems. Warranty Overview Refer to the Contech Engineered Solutions LLC Stormwater Treatment System LIMITED WARRANTY for further information. The following conditions may void the Filterra system’s warranty and waive the manufacturer provided Activation and Maintenance services: • Unauthorized activation or performance of any of the items listed in the activation overview • Any tampering, modifications or damage to the Filterra system or runoff protection devices • Removal of any Filterra system components • Failure to prevent construction related runoff from entering the Filterra system • Failure to properly store and protect any Filterra components (including media and underdrain stone) that may be shipped separately from the vault Routine Maintenance Guidelines With proper routine maintenance, the biofiltration media within the Filterra system should last as long as traditional bioretention media. Routine maintenance is included by the manufacturer on all Filterra systems for the first year after activation. This includes a maximum of 2 visits to remove debris, replace pretreatment mulch, and prune the vegetation. More information is provided in the Operations and Maintenance Guidelines. Some Filterra systems also contain pretreatment or outlet bays. Depending on site pollutant loading, these bays may require periodic removal of debris, however this is not included in the first year of maintenance, and would likely not be required within the first year of operation. These services, as well as routine maintenance outside of the included first year, can be provided by certified maintenance providers listed on the Contech website. Training can also be provided to other stormwater maintenance or landscape providers. A-15 www.ContechES.com/filterra | 800-338-1122 7 Why Maintain? All stormwater treatment systems require maintenance for effective operation. This necessity is often incorporated in your property’s permitting process as a legally binding BMP maintenance agreement. Other reasons to maintain are: • Avoiding legal challenges from your jurisdiction’s maintenance enforcement program. • Prolonging the expected lifespan of your Filterra media. • Avoiding more costly media replacement. • Helping reduce pollutant loads leaving your property. Simple maintenance of the Filterra is required to continue effective pollutant removal from stormwater runoff before discharge into downstream waters. This procedure will also extend the longevity of the living biofilter system. The unit will recycle and accumulate pollutants within the biomass, but is also subjected to other materials entering the inlet. This may include trash, silt and leaves etc. which will be contained above the mulch layer. Too much silt may inhibit the Filterra’s flow rate, which is the reason for site stabilization before activation. Regular replacement of the mulch stops accumulation of such sediment. When to Maintain? Contech includes a 1-year maintenance plan with each system purchase. Annual included maintenance consists of a maximum of two (2) scheduled visits. Additional maintenance may be necessary depending on sediment and trash loading (by Owner or at additional cost). The start of the maintenance plan begins when the system is activated. Maintenance visits are scheduled seasonally; the spring visit aims to clean up after winter loads including salts and sands while the fall visit helps the system by removing excessive leaf litter. It has been found that in regions which receive between 30-50 inches of annual rainfall, (2) two visits are generally required; regions with less rainfall often only require (1) one visit per annum. Varying land uses can affect maintenance frequency; e.g. some fast food restaurants require more frequent trash removal. Contributing drainage areas which are subject to new development wherein the recommended erosion and sediment control measures have not been implemented may require additional maintenance visits. Some sites may be subjected to extreme sediment or trash loads, requiring more frequent maintenance visits. This is the reason for detailed notes of maintenance actions per unit, helping the Supplier and Owner predict future maintenance frequencies, reflecting individual site conditions. Owners must promptly notify the (maintenance) Supplier of any damage to the plant(s), which constitute(s) an integral part of the bioretention technology. Owners should also advise other landscape or maintenance contractors to leave all maintenance to the Supplier (i.e. no pruning or fertilizing) during the first year. A-15 www.ContechES.com/filterra | 800-338-11228 Exclusion of Services Clean up due to major contamination such as oils, chemicals, toxic spills, etc. will result in additional costs and are not covered under the Supplier maintenance contract. Should a major contamination event occur the Owner must block off the outlet pipe of the Filterra (where the cleaned runoff drains to, such as drop inlet) and block off the throat of the Filterra. The Supplier should be informed immediately. Maintenance Visit Summary Each maintenance visit consists of the following simple tasks (detailed instructions below). 1. Inspection of Filterra and surrounding area 2. Removal of tree grate and erosion control stones 3. Removal of debris, trash and mulch 4. Mulch replacement 5. Plant health evaluation and pruning or replacement as necessary 6. Clean area around Filterra 7. Complete paperwork Maintenance Tools, Safety Equipment and Supplies Ideal tools include: camera, bucket, shovel, broom, pruners, hoe/rake, and tape measure. Appropriate Personal Protective Equipment (PPE) should be used in accordance with local or company procedures. This may include impervious gloves where the type of trash is unknown, high visibility clothing and barricades when working in close proximity to traffic and also safety hats and shoes. A T-Bar or crowbar should be used for moving the tree grates (up to 170 lbs ea.). Most visits require minor trash removal and a full replacement of mulch. See below for actual number of bagged mulch that is required in each media bay size. Mulch should be a double shredded, hardwood variety. Some visits may require additional Filterra engineered soil media available from the Supplier. Box Length Box Width Filter Surface Area (ft²)Volume at 3” (ft³)# of 2 ft³ Mulch Bags 44442 64663 84884 66995 8 6 12 12 6 10615158 12618189 13 7 232312 A-15 www.ContechES.com/filterra | 800-338-1122 9 1. Inspection of Filterra and surrounding area • Record individual unit before maintenance with photograph (numbered). Record on Maintenance Report (see example in this document) the following: 2. Removal of tree grate and erosion control stones • Remove cast iron grates for access into Filterra box. • Dig out silt (if any) and mulch and remove trash & foreign items. 3. Removal of debris, trash and mulch • After removal of mulch and debris, measure distance from the top of the Filterra engineered media soil to the top of the top slab. Compare the measured distance to the distance shown on the approved Contract Drawings for the system. Add Filterra media (not top soil or other) to bring media up as needed to distance indicated on drawings. Record on Maintenance Report the following: Standing Water yes | no Damage to Box Structure yes | no Damage to Grate yes | no Is Bypass Clear yes | no If yes answered to any of these observations, record with close-up photograph (numbered). Record on Maintenance Report the following: Silt/Clay yes | no Cups/ Bags yes | no Leaves yes | no Buckets Removed ________ Record on Maintenance Report the following: Distance to Top of Top Slab (inches) ________ Inches of Media Added ________ Maintenance Visit Procedure Keep sufficient documentation of maintenance actions to predict location specific maintenance frequencies and needs. An example Maintenance Report is included in this manual. A-15 www.ContechES.com/filterra | 800-338-112210 4. Mulch replacement • Add double shredded mulch evenly across the entire unit to a depth of 3”. • Refer to Filterra Mulch Specifications for information on acceptable sources. • Ensure correct repositioning of erosion control stones by the Filterra inlet to allow for entry of trash during a storm event. • Replace Filterra grates correctly using appropriate lifting or moving tools, taking care not to damage the plant. 5. Plant health evaluation and pruning or replacement as necessary • Examine the plant’s health and replace if necessary. • Prune as necessary to encourage growth in the correct directions 6. Clean area around Filterra • Clean area around unit and remove all refuse to be disposed of appropriately. 7. Complete paperwork • Deliver Maintenance Report and photographs to appropriate location (normally Contech during maintenance contract period). • Some jurisdictions may require submission of maintenance reports in accordance with approvals. It is the responsibility of the Owner to comply with local regulations. Record on Maintenance Report the following: Height above Grate _____________________(ft) Width at Widest Point _____________________(ft) Health healthy | unhealthy Damage to Plant yes | no Plant Replaced yes | no A-15 www.ContechES.com/filterra | 800-338-1122 11 Maintenance Checklist Filterra Inspection & Maintenance Log Filterra System Size/Model: _____________________________Location: ____________________________________________ Drainage System Failure Problem Conditions to Check Condition that Should Exist Actions Inlet Excessive sediment or trash accumulation. Accumulated sediments or trash impair free flow of water into Filterra. Inlet should be free of obstructions allowing free distributed flow of water into Filterra. Sediments and/or trash should be removed. Mulch Cover Trash and floatable debris accumulation. Excessive trash and/or debris accumulation. Minimal trash or other debris on mulch cover. Trash and debris should be removed and mulch cover raked level. Ensure bark nugget mulch is not used. Mulch Cover “Ponding” of water on mulch cover. “Ponding” in unit could be indicative of clogging due to excessive fine sediment accumulation or spill of petroleum oils. Stormwater should drain freely and evenly through mulch cover. Recommend contact manufacturer and replace mulch as a minimum. Vegetation Plants not growing or in poor condition. Soil/mulch too wet, evidence of spill. Incorrect plant selection. Pest infestation. Vandalism to plants. Plants should be healthy and pest free.Contact manufacturer for advice. Vegetation Plant growth excessive. Plants should be appropriate to the species and location of Filterra. Trim/prune plants in accordance with typical landscaping and safety needs. Structure Structure has visible cracks. Cracks wider than 1/2 inch or evidence of soil particles entering the structure through the cracks. Vault should be repaired. Maintenance is ideally to be performed twice annually. Date Mulch & Debris Removed Depth of Mulch Added Mulch Brand Height of Vegetation Above Grate Vegetation Species Issues with System Comments 1/1/17 5 – 5 gal Buckets 3” Lowe’s Premium Brown Mulch 4’Galaxy Magnolia - Standing water in downstream structure - Removed blockage in downstream structure A-15 www.ContechES.com/filterra | 800-338-112212 Appendix 1 – Filterra® Activation Checklist Project Name: ________________________________________Company: ______________________________________________ Site Contact Name: _______________________________________ Site Contact Phone/Email: ____________________________ Site Owner/End User Name: _________________________Site Owner/End User Phone/Email: ____________________________ Preferred Activation Date: ___________________________________(provide 2 weeks minimum from date this form is submitted) Site Designation System Size Final Pavement / Top Coat Complete Landscaping Complete / Grass Emerging Construction materials / Piles / Debris Removed Throat Opening Measures 4” Min. Height Plant Species Requested Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No Yes No NOTE: A charge of $500.00 will be invoiced for each Activation visit requested by Customer where Contech determines that the site does not meet the conditions required for Activation. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized Activations will void the system warranty and waive manufacturer supplied Activation and 1st Year Maintenance. Attach additional sheets as necessary. Signature Date ENGINEERED SOLUTIONS A-15 www.ContechES.com/filterra | 800-338-1122 13 Appendix 2 – Planting Requirements for Filterra® Systems Plant Material Selection • Select plant(s) as specified in the engineering plans and specifications. • Select plant(s) with full root development but not to the point where root bound. • Use local nursery container plants only. Ball and burlapped plants are not permitted. • For precast Filterra systems with a tree grate, plant(s) must not have scaffold limbs at least 14 inches from the crown due to spacing between the top of the mulch and the tree grate. Lower branches can be pruned away provided there are sufficient scaffold branches for tree or shrub development. • For precast Filterra systems with a tree grate, at the time of installation, it is required that plant(s) must be at least 6” above the tree grate opening at installation for all Filterra configurations. This DOES NOT apply to Full Grate Cover designs. • Plant(s) shall not have a mature height greater than 25 feet. • For standard 21” media depth, a 7 – 15 gallon container size shall be used. Media less than 21” (Filterra boxes only) will require smaller container plants. • For precast Filterra systems, plant(s) should have a single trunk at installation, and pruning may be necessary at activation and maintenance for some of the faster growing species, or species known to produce basal sprouts. Plant Installation • During transport protect the plant leaves from wind and excessive jostling. • Prior to removing the plant(s) from the container, ensure the soil moisture is sufficient to maintain the integrity of the root ball. If needed, pre-wet the container plant. • Cut away any roots which are growing out of the container drain holes. Plants with excessive root growth from the drain holes should be rejected. • Plant(s) should be carefully removed from the pot by gently pounding on the sides of the container with the fist to loosen root ball. Then carefully slide out. Do not lift plant(s) by trunk as this can break roots and cause soil to fall off. Extract the root ball in a horizontal position and support it to prevent it from breaking apart. Alternatively the pot can be cut away to minimize root ball disturbance. • Remove any excess soil from above the root flare after removing plant(s) from container. • Excavate a hole with a diameter 4” greater than the root ball, gently place the plant(s). • If plant(s) have any circling roots from being pot bound, gently tease them loose without breaking them. • If root ball has a root mat on the bottom, it should be shaved off with a knife just above the mat line. • Plant the tree/shrub/grass with the top of the root ball 1” above surrounding media to allow for settling. • All plants should have the main stem centered in the tree grate (where applicable) upon completion of installation. • With all trees/shrubs, remove dead, diseased, crossed/rubbing, sharply crotched branches or branches growing excessively long or in wrong direction compared to majority of branches. • To prevent transplant shock (especially if planting takes place in the hot season), it may be necessary to prune some of the foliage to compensate for reduced root uptake capacity. This is accomplished by pruning away some of the smaller secondary branches or a main scaffold branch if there are too many. Too much foliage relative to the root ball can dehydrate and damage the plant. • Plant staking may be required. A-15 www.ContechES.com/filterra | 800-338-112214 Mulch Installation • Only mulch that has been meeting Contech Engineered Solutions’ mulch specifications can be used in the Filterra system. • Mulch must be applied to a depth of 3” evenly over the surface of the media. Irrigation Requirements • Each Filterra system must receive adequate irrigation to ensure survival of the living system during periods of drier weather. • Irrigation sources include rainfall runoff from downspouts and/or gutter flow, applied water through the tree grate or in some cases from an irrigation system with emitters installed during construction. • At Activation: Apply about one (cool climates) to two (warm climates) gallons of water per inch of trunk diameter over the root ball. • During Establishment: In common with all plants, each Filterra plant will require more frequent watering during the establishment period. One inch of applied water per week for the first three months is recommended for cooler climates (2 to 3 inches for warmer climates). If the system is receiving rainfall runoff from the drainage area, then irrigation may not be needed. Inspection of the soil moisture content can be evaluated by gently brushing aside the mulch layer and feeling the soil. Be sure to replace the mulch when the assessment is complete. Irrigate as needed**. • Established Plants: Established plants have fully developed root systems and can access the entire water column in the media. Therefore irrigation is less frequent but requires more applied water when performed. For a mature system assume 3.5 inches of available water within the media matrix. Irrigation demand can be estimated as 1” of irrigation demand per week. Therefore if dry periods exceed 3 weeks, irrigation may be required. It is also important to recognize that plants which are exposed to windy areas and reflected heat from paved surfaces may need more frequent irrigation. Long term care should develop a history which is more site specific. ** Five gallons per square yard approximates 1 inch of water Therefore for a 6’ by 6’ Filterra approximately 20-60 gallons of water is needed. To ensure even distribution of water it needs to be evenly sprinkled over the entire surface of the filter bed, with special attention to make sure the root ball is completely wetted. NOTE: if needed, measure the time it takes to fill a five gallon bucket to estimate the applied water flow rate then calculate the time needed to irrigate the Filterra. For example, if the flow rate of the sprinkler is 5 gallons/minute then it would take 12 minutes to irrigate a 6’ by 6’ filter. A-15 Notes ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ A-15 PDF 1/18 © 2018 Contech Engineered Solutions LLC, a QUIKRETE Company 9025 Centre Pointe Drive, Suite 400 West Chester, OH 45069 info@conteches.com | 800-338-1122 www.ContechES.com ALL RIGHTS RESERVED. PRINTED IN THE USA. NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. ® Bioretention Systems ENGINEERED SOLUTIONS A-15 N 0 100 2001" = 100 FEETGRAPHIC SCALE500 Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Appendix B Calculations B-1 .................... WWHM Flow Control Calculations B-2 .................... WWHM Water Quality Treatment Calculations B-3 .................... Conveyance System Analysis and Design (to be provided with Final TIR) WWHM2012 PROJECT REPORT 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 2 General Model Information Project Name: 20231204 NorthDetentionModules Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/14/2023 Gage: Seatac Data Start: 1948/10/01 00:00 Data End: 2009/09/30 00:00 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2021/08/18 Version: 4.2.18 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 3 Landuse Basin Data Predeveloped Land Use North Half Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 5.474 Pervious Total 5.474 Impervious Land Use acre Impervious Total 0 Basin Total 5.474 Element Flows To: Surface Interflow Groundwater 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 4 Mitigated Land Use North Half Detain Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.765 Pervious Total 0.765 Impervious Land Use acre ROADS FLAT 3.994 Impervious Total 3.994 Basin Total 4.759 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 1 Gravel Trench Bed 1 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 5 Undetained Bypass: Yes GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.715 Pervious Total 0.715 Impervious Land Use acre Impervious Total 0 Basin Total 0.715 Element Flows To: Surface Interflow Groundwater 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 6 Routing Elements Predeveloped Routing 20231204 NorthDetentionModules 12/14/2023 2:51:22 PM Page 7 Mitigated Routing Gravel Trench Bed 1 Bottom Length: 378.00 ft. Bottom Width: 40.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 6 Pour Space of material for first layer: 0.97 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Discharge Structure Riser Height: 5.95 ft. Riser Diameter: 36 in. Orifice 1 Diameter: 1.1 in. Elevation:0 ft. Orifice 2 Diameter: 1.25 in. Elevation:3.5 ft. Orifice 3 Diameter: 2.1 in. Elevation:4.4 ft. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.347 0.000 0.000 0.000 0.0667 0.347 0.022 0.008 0.000 0.1333 0.347 0.044 0.012 0.000 0.2000 0.347 0.067 0.014 0.000 0.2667 0.347 0.089 0.017 0.000 0.3333 0.347 0.112 0.019 0.000 0.4000 0.347 0.134 0.020 0.000 0.4667 0.347 0.157 0.022 0.000 0.5333 0.347 0.179 0.024 0.000 0.6000 0.347 0.202 0.025 0.000 0.6667 0.347 0.224 0.026 0.000 0.7333 0.347 0.246 0.028 0.000 0.8000 0.347 0.269 0.029 0.000 0.8667 0.347 0.291 0.030 0.000 0.9333 0.347 0.314 0.031 0.000 1.0000 0.347 0.336 0.032 0.000 1.0667 0.347 0.359 0.033 0.000 1.1333 0.347 0.381 0.035 0.000 1.2000 0.347 0.404 0.036 0.000 1.2667 0.347 0.426 0.037 0.000 1.3333 0.347 0.448 0.037 0.000 1.4000 0.347 0.471 0.038 0.000 1.4667 0.347 0.493 0.039 0.000 1.5333 0.347 0.516 0.040 0.000 1.6000 0.347 0.538 0.041 0.000 1.6667 0.347 0.561 0.042 0.000 1.7333 0.347 0.583 0.043 0.000 1.8000 0.347 0.606 0.044 0.000 1.8667 0.347 0.628 0.044 0.000 1.9333 0.347 0.650 0.045 0.000 20231204 NorthDetentionModules 12/14/2023 2:51:23 PM Page 8 2.0000 0.347 0.673 0.046 0.000 2.0667 0.347 0.695 0.047 0.000 2.1333 0.347 0.718 0.048 0.000 2.2000 0.347 0.740 0.048 0.000 2.2667 0.347 0.763 0.049 0.000 2.3333 0.347 0.785 0.050 0.000 2.4000 0.347 0.808 0.050 0.000 2.4667 0.347 0.830 0.051 0.000 2.5333 0.347 0.853 0.052 0.000 2.6000 0.347 0.875 0.052 0.000 2.6667 0.347 0.897 0.053 0.000 2.7333 0.347 0.920 0.054 0.000 2.8000 0.347 0.942 0.054 0.000 2.8667 0.347 0.965 0.055 0.000 2.9333 0.347 0.987 0.056 0.000 3.0000 0.347 1.010 0.056 0.000 3.0667 0.347 1.032 0.057 0.000 3.1333 0.347 1.055 0.058 0.000 3.2000 0.347 1.077 0.058 0.000 3.2667 0.347 1.099 0.059 0.000 3.3333 0.347 1.122 0.059 0.000 3.4000 0.347 1.144 0.060 0.000 3.4667 0.347 1.167 0.061 0.000 3.5333 0.347 1.189 0.069 0.000 3.6000 0.347 1.212 0.075 0.000 3.6667 0.347 1.234 0.080 0.000 3.7333 0.347 1.257 0.083 0.000 3.8000 0.347 1.279 0.087 0.000 3.8667 0.347 1.301 0.090 0.000 3.9333 0.347 1.324 0.093 0.000 4.0000 0.347 1.346 0.095 0.000 4.0667 0.347 1.369 0.098 0.000 4.1333 0.347 1.391 0.100 0.000 4.2000 0.347 1.414 0.102 0.000 4.2667 0.347 1.436 0.105 0.000 4.3333 0.347 1.459 0.107 0.000 4.4000 0.347 1.481 0.109 0.000 4.4667 0.347 1.503 0.142 0.000 4.5333 0.347 1.526 0.156 0.000 4.6000 0.347 1.548 0.168 0.000 4.6667 0.347 1.571 0.178 0.000 4.7333 0.347 1.593 0.187 0.000 4.8000 0.347 1.616 0.196 0.000 4.8667 0.347 1.638 0.203 0.000 4.9333 0.347 1.661 0.211 0.000 5.0000 0.347 1.683 0.218 0.000 5.0667 0.347 1.705 0.224 0.000 5.1333 0.347 1.728 0.231 0.000 5.2000 0.347 1.750 0.237 0.000 5.2667 0.347 1.773 0.243 0.000 5.3333 0.347 1.795 0.248 0.000 5.4000 0.347 1.818 0.254 0.000 5.4667 0.347 1.840 0.259 0.000 5.5333 0.347 1.863 0.265 0.000 5.6000 0.347 1.885 0.270 0.000 5.6667 0.347 1.907 0.275 0.000 5.7333 0.347 1.930 0.280 0.000 5.8000 0.347 1.952 0.285 0.000 20231204 NorthDetentionModules 12/14/2023 2:51:23 PM Page 9 5.8667 0.347 1.975 0.289 0.000 5.9333 0.347 1.997 0.294 0.000 6.0000 0.347 2.020 0.654 0.000 20231204 NorthDetentionModules 12/14/2023 2:51:23 PM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 5.474 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 1.48 Total Impervious Area: 3.994 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.16094 5 year 0.252763 10 year 0.3048 25 year 0.35993 50 year 0.394044 100 year 0.423059 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.123364 5 year 0.196908 10 year 0.255345 25 year 0.340933 50 year 0.413667 100 year 0.494473 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.158 0.157 1950 0.197 0.181 1951 0.354 0.317 1952 0.112 0.065 1953 0.090 0.104 1954 0.139 0.084 1955 0.221 0.090 1956 0.176 0.197 1957 0.142 0.113 1958 0.160 0.087 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 11 1959 0.137 0.079 1960 0.240 0.230 1961 0.135 0.141 1962 0.084 0.060 1963 0.115 0.095 1964 0.152 0.116 1965 0.109 0.128 1966 0.105 0.081 1967 0.219 0.184 1968 0.137 0.106 1969 0.134 0.106 1970 0.110 0.095 1971 0.118 0.125 1972 0.264 0.260 1973 0.120 0.127 1974 0.130 0.110 1975 0.176 0.122 1976 0.127 0.093 1977 0.015 0.058 1978 0.112 0.105 1979 0.068 0.058 1980 0.250 0.254 1981 0.100 0.083 1982 0.192 0.231 1983 0.172 0.096 1984 0.106 0.072 1985 0.063 0.076 1986 0.279 0.123 1987 0.247 0.219 1988 0.097 0.073 1989 0.064 0.064 1990 0.516 0.337 1991 0.311 0.275 1992 0.120 0.093 1993 0.125 0.069 1994 0.042 0.058 1995 0.179 0.130 1996 0.377 0.302 1997 0.315 0.278 1998 0.071 0.096 1999 0.296 0.257 2000 0.124 0.099 2001 0.022 0.049 2002 0.136 0.160 2003 0.174 0.124 2004 0.225 0.302 2005 0.162 0.102 2006 0.191 0.194 2007 0.383 0.386 2008 0.494 0.305 2009 0.243 0.167 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.5159 0.3857 2 0.4940 0.3368 3 0.3829 0.3165 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 12 4 0.3771 0.3053 5 0.3544 0.3022 6 0.3152 0.3016 7 0.3106 0.2782 8 0.2956 0.2750 9 0.2790 0.2598 10 0.2639 0.2567 11 0.2501 0.2539 12 0.2467 0.2313 13 0.2425 0.2296 14 0.2396 0.2193 15 0.2252 0.1968 16 0.2212 0.1942 17 0.2188 0.1841 18 0.1971 0.1807 19 0.1923 0.1670 20 0.1906 0.1601 21 0.1789 0.1574 22 0.1763 0.1410 23 0.1760 0.1304 24 0.1740 0.1283 25 0.1724 0.1266 26 0.1616 0.1254 27 0.1600 0.1244 28 0.1581 0.1228 29 0.1520 0.1222 30 0.1420 0.1161 31 0.1387 0.1128 32 0.1373 0.1099 33 0.1365 0.1062 34 0.1364 0.1058 35 0.1352 0.1050 36 0.1335 0.1035 37 0.1301 0.1020 38 0.1275 0.0991 39 0.1248 0.0961 40 0.1244 0.0958 41 0.1199 0.0952 42 0.1198 0.0946 43 0.1178 0.0934 44 0.1155 0.0926 45 0.1118 0.0899 46 0.1117 0.0870 47 0.1101 0.0836 48 0.1088 0.0833 49 0.1064 0.0806 50 0.1046 0.0793 51 0.1000 0.0760 52 0.0974 0.0727 53 0.0903 0.0717 54 0.0841 0.0691 55 0.0713 0.0645 56 0.0676 0.0643 57 0.0635 0.0599 58 0.0631 0.0582 59 0.0419 0.0581 60 0.0223 0.0578 61 0.0152 0.0490 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 13 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 14 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0805 17781 17109 96 Pass 0.0836 16418 15528 94 Pass 0.0868 15248 14080 92 Pass 0.0900 14149 12765 90 Pass 0.0931 12853 11203 87 Pass 0.0963 11914 10256 86 Pass 0.0995 11034 9398 85 Pass 0.1026 10260 8639 84 Pass 0.1058 9559 7946 83 Pass 0.1090 8926 7225 80 Pass 0.1121 8173 6254 76 Pass 0.1153 7646 5634 73 Pass 0.1185 7131 5033 70 Pass 0.1216 6682 4374 65 Pass 0.1248 6248 3824 61 Pass 0.1280 5884 3373 57 Pass 0.1311 5448 3037 55 Pass 0.1343 5142 2885 56 Pass 0.1375 4849 2755 56 Pass 0.1407 4581 2663 58 Pass 0.1438 4327 2573 59 Pass 0.1470 4092 2500 61 Pass 0.1502 3797 2396 63 Pass 0.1533 3563 2334 65 Pass 0.1565 3371 2282 67 Pass 0.1597 3172 2250 70 Pass 0.1628 2997 2197 73 Pass 0.1660 2834 2143 75 Pass 0.1692 2603 2043 78 Pass 0.1723 2460 1978 80 Pass 0.1755 2329 1910 82 Pass 0.1787 2182 1849 84 Pass 0.1818 2059 1778 86 Pass 0.1850 1939 1715 88 Pass 0.1882 1793 1638 91 Pass 0.1913 1704 1567 91 Pass 0.1945 1606 1507 93 Pass 0.1977 1507 1442 95 Pass 0.2008 1397 1402 100 Pass 0.2040 1314 1358 103 Pass 0.2072 1225 1303 106 Pass 0.2103 1160 1252 107 Pass 0.2135 1104 1204 109 Pass 0.2167 1059 1158 109 Pass 0.2198 1010 1109 109 Pass 0.2230 930 1028 110 Pass 0.2262 884 968 109 Pass 0.2293 843 904 107 Pass 0.2325 795 853 107 Pass 0.2357 748 817 109 Pass 0.2388 723 768 106 Pass 0.2420 668 704 105 Pass 0.2452 633 653 103 Pass 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 15 0.2483 600 602 100 Pass 0.2515 571 537 94 Pass 0.2547 542 481 88 Pass 0.2578 508 442 87 Pass 0.2610 473 396 83 Pass 0.2642 437 371 84 Pass 0.2673 404 349 86 Pass 0.2705 376 325 86 Pass 0.2737 352 300 85 Pass 0.2768 335 281 83 Pass 0.2800 296 254 85 Pass 0.2832 274 234 85 Pass 0.2864 258 221 85 Pass 0.2895 239 209 87 Pass 0.2927 219 193 88 Pass 0.2959 203 171 84 Pass 0.2990 180 134 74 Pass 0.3022 158 112 70 Pass 0.3054 146 100 68 Pass 0.3085 133 89 66 Pass 0.3117 120 82 68 Pass 0.3149 111 72 64 Pass 0.3180 97 60 61 Pass 0.3212 91 56 61 Pass 0.3244 83 51 61 Pass 0.3275 78 48 61 Pass 0.3307 69 43 62 Pass 0.3339 63 40 63 Pass 0.3370 54 34 62 Pass 0.3402 48 23 47 Pass 0.3434 42 17 40 Pass 0.3465 38 8 21 Pass 0.3497 33 7 21 Pass 0.3529 29 7 24 Pass 0.3560 22 6 27 Pass 0.3592 21 6 28 Pass 0.3624 20 5 25 Pass 0.3655 19 4 21 Pass 0.3687 17 4 23 Pass 0.3719 14 3 21 Pass 0.3750 12 3 25 Pass 0.3782 9 2 22 Pass 0.3814 4 2 50 Pass 0.3845 3 1 33 Pass 0.3877 300Pass 0.3909 300Pass 0.3940 300Pass 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 16 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. 20231204 NorthDetentionModules 12/14/2023 2:51:59 PM Page 17 LID Report 20231204 NorthDetentionModules 12/14/2023 2:52:22 PM Page 18 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20231204 NorthDetentionModules 12/14/2023 2:52:22 PM Page 19 Appendix Predeveloped Schematic 20231204 NorthDetentionModules 12/14/2023 2:52:23 PM Page 20 Mitigated Schematic 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 21 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231204 NorthDetentionModules.wdm MESSU 25 Pre20231204 NorthDetentionModules.MES 27 Pre20231204 NorthDetentionModules.L61 28 Pre20231204 NorthDetentionModules.L62 30 POC20231204 NorthDetentionModules1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 North Half MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 22 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 23 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** North Half*** PERLND 10 5.474 COPY 501 12 PERLND 10 5.474 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 24 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 25 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231204 NorthDetentionModules.wdm MESSU 25 Mit20231204 NorthDetentionModules.MES 27 Mit20231204 NorthDetentionModules.L61 28 Mit20231204 NorthDetentionModules.L62 30 POC20231204 NorthDetentionModules1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 RCHRES 1 COPY 1 COPY 501 COPY 601 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Gravel Trench Bed 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 601 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 26 <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 27 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** North Half Detain*** PERLND 16 0.765 RCHRES 1 2 PERLND 16 0.765 RCHRES 1 3 IMPLND 1 3.994 RCHRES 1 5 Undetained*** PERLND 16 0.715 COPY 501 12 PERLND 16 0.715 COPY 601 12 PERLND 16 0.715 COPY 501 13 PERLND 16 0.715 COPY 601 13 ******Routing****** PERLND 16 0.765 COPY 1 12 IMPLND 1 3.994 COPY 1 15 PERLND 16 0.765 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Gravel Trench Be-020 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 28 * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.07 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.347107 0.000000 0.000000 0.066667 0.347107 0.022446 0.008478 0.133333 0.347107 0.044893 0.011990 0.200000 0.347107 0.067339 0.014684 0.266667 0.347107 0.089785 0.016956 0.333333 0.347107 0.112231 0.018958 0.400000 0.347107 0.134678 0.020767 0.466667 0.347107 0.157124 0.022431 0.533333 0.347107 0.179570 0.023980 0.600000 0.347107 0.202017 0.025434 0.666667 0.347107 0.224463 0.026810 0.733333 0.347107 0.246909 0.028119 0.800000 0.347107 0.269355 0.029369 0.866667 0.347107 0.291802 0.030568 0.933333 0.347107 0.314248 0.031722 1.000000 0.347107 0.336694 0.032836 1.066667 0.347107 0.359140 0.033912 1.133333 0.347107 0.381587 0.034956 1.200000 0.347107 0.404033 0.035970 1.266667 0.347107 0.426479 0.036955 1.333333 0.347107 0.448926 0.037915 1.400000 0.347107 0.471372 0.038852 1.466667 0.347107 0.493818 0.039766 1.533333 0.347107 0.516264 0.040660 1.600000 0.347107 0.538711 0.041534 1.666667 0.347107 0.561157 0.042390 1.733333 0.347107 0.583603 0.043230 1.800000 0.347107 0.606050 0.044053 1.866667 0.347107 0.628496 0.044862 1.933333 0.347107 0.650942 0.045656 2.000000 0.347107 0.673388 0.046436 2.066667 0.347107 0.695835 0.047204 2.133333 0.347107 0.718281 0.047959 2.200000 0.347107 0.740727 0.048703 2.266667 0.347107 0.763174 0.049435 2.333333 0.347107 0.785620 0.050157 2.400000 0.347107 0.808066 0.050869 2.466667 0.347107 0.830512 0.051570 2.533333 0.347107 0.852959 0.052263 2.600000 0.347107 0.875405 0.052946 2.666667 0.347107 0.897851 0.053620 2.733333 0.347107 0.920298 0.054286 2.800000 0.347107 0.942744 0.054944 2.866667 0.347107 0.965190 0.055595 2.933333 0.347107 0.987636 0.056237 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 29 3.000000 0.347107 1.010083 0.056873 3.066667 0.347107 1.032529 0.057501 3.133333 0.347107 1.054975 0.058123 3.200000 0.347107 1.077421 0.058738 3.266667 0.347107 1.099868 0.059347 3.333333 0.347107 1.122314 0.059949 3.400000 0.347107 1.144760 0.060546 3.466667 0.347107 1.167207 0.061136 3.533333 0.347107 1.189653 0.069463 3.600000 0.347107 1.212099 0.075710 3.666667 0.347107 1.234545 0.080186 3.733333 0.347107 1.256992 0.083926 3.800000 0.347107 1.279438 0.087232 3.866667 0.347107 1.301884 0.090243 3.933333 0.347107 1.324331 0.093033 4.000000 0.347107 1.346777 0.095653 4.066667 0.347107 1.369223 0.098135 4.133333 0.347107 1.391669 0.100500 4.200000 0.347107 1.414116 0.102768 4.266667 0.347107 1.436562 0.104951 4.333333 0.347107 1.459008 0.107059 4.400000 0.347107 1.481455 0.109102 4.466667 0.347107 1.503901 0.141984 4.533333 0.347107 1.526347 0.156713 4.600000 0.347107 1.548793 0.168415 4.666667 0.347107 1.571240 0.178530 4.733333 0.347107 1.593686 0.187620 4.800000 0.347107 1.616132 0.195972 4.866667 0.347107 1.638579 0.203758 4.933333 0.347107 1.661025 0.211092 5.000000 0.347107 1.683471 0.218052 5.066667 0.347107 1.705917 0.224695 5.133333 0.347107 1.728364 0.231067 5.200000 0.347107 1.750810 0.237200 5.266667 0.347107 1.773256 0.243123 5.333333 0.347107 1.795702 0.248857 5.400000 0.347107 1.818149 0.254422 5.466667 0.347107 1.840595 0.259833 5.533333 0.347107 1.863041 0.265103 5.600000 0.347107 1.885488 0.270244 5.666667 0.347107 1.907934 0.275265 5.733333 0.347107 1.930380 0.280175 5.800000 0.347107 1.952826 0.284983 5.866667 0.347107 1.975273 0.289693 5.933333 0.347107 1.997719 0.294313 6.000000 0.347107 2.020165 0.654793 6.066667 0.347107 2.043306 1.570828 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 RCHRES 1 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL RCHRES 1 HYDR RO 1 1 1 WDM 1008 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1009 STAG ENGL REPL END EXT TARGETS 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 30 MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 31 Predeveloped HSPF Message File 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 32 Mitigated HSPF Message File 20231204 NorthDetentionModules 12/14/2023 2:52:25 PM Page 33 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 2 General Model Information Project Name: 20231213 NorthDetentionPond Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/14/2023 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2021/08/18 Version: 4.2.18 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 3 Landuse Basin Data Predeveloped Land Use South Half Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 2.221 Pervious Total 2.221 Impervious Land Use acre Impervious Total 0 Basin Total 2.221 Element Flows To: Surface Interflow Groundwater 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 4 Mitigated Land Use North Pond Treat Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 1.205 Pervious Total 1.205 Impervious Land Use acre ROADS FLAT 0.673 Impervious Total 0.673 Basin Total 1.878 Element Flows To: Surface Interflow Groundwater Surface retention 1 Surface retention 1 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 5 North Pond Detain Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.343 Impervious Total 0.343 Basin Total 0.343 Element Flows To: Surface Interflow Groundwater Trapezoidal Pond 1 Trapezoidal Pond 1 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 6 Routing Elements Predeveloped Routing 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 7 Mitigated Routing Trapezoidal Pond 1 Bottom Length: 80.00 ft. Bottom Width: 39.00 ft. Depth: 6 ft. Volume at riser head: 0.5975 acre-feet. Side slope 1: 3 To 1 Side slope 2: 3 To 1 Side slope 3: 3 To 1 Side slope 4: 3 To 1 Discharge Structure Riser Height: 5 ft. Riser Diameter: 36 in. Orifice 1 Diameter: 0.8 in. Elevation:0.5 ft. Orifice 2 Diameter: 1.3 in. Elevation:3.6 ft. Orifice 3 Diameter: 1.6 in. Elevation:4.4 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.071 0.000 0.000 0.000 0.0667 0.072 0.004 0.000 0.000 0.1333 0.073 0.009 0.000 0.000 0.2000 0.074 0.014 0.000 0.000 0.2667 0.076 0.019 0.000 0.000 0.3333 0.077 0.024 0.000 0.000 0.4000 0.078 0.030 0.000 0.000 0.4667 0.079 0.035 0.000 0.000 0.5333 0.080 0.040 0.003 0.000 0.6000 0.081 0.046 0.005 0.000 0.6667 0.082 0.051 0.007 0.000 0.7333 0.084 0.057 0.008 0.000 0.8000 0.085 0.062 0.009 0.000 0.8667 0.086 0.068 0.010 0.000 0.9333 0.087 0.074 0.011 0.000 1.0000 0.088 0.080 0.012 0.000 1.0667 0.090 0.086 0.013 0.000 1.1333 0.091 0.092 0.013 0.000 1.2000 0.092 0.098 0.014 0.000 1.2667 0.093 0.104 0.015 0.000 1.3333 0.094 0.110 0.015 0.000 1.4000 0.096 0.117 0.016 0.000 1.4667 0.097 0.123 0.017 0.000 1.5333 0.098 0.130 0.017 0.000 1.6000 0.100 0.136 0.018 0.000 1.6667 0.101 0.143 0.018 0.000 1.7333 0.102 0.150 0.019 0.000 1.8000 0.103 0.157 0.019 0.000 1.8667 0.105 0.164 0.020 0.000 1.9333 0.106 0.171 0.020 0.000 2.0000 0.107 0.178 0.021 0.000 2.0667 0.109 0.185 0.021 0.000 2.1333 0.110 0.192 0.022 0.000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 8 2.2000 0.111 0.200 0.022 0.000 2.2667 0.113 0.207 0.023 0.000 2.3333 0.114 0.215 0.023 0.000 2.4000 0.115 0.222 0.023 0.000 2.4667 0.117 0.230 0.024 0.000 2.5333 0.118 0.238 0.024 0.000 2.6000 0.119 0.246 0.025 0.000 2.6667 0.121 0.254 0.025 0.000 2.7333 0.122 0.262 0.026 0.000 2.8000 0.124 0.270 0.026 0.000 2.8667 0.125 0.279 0.026 0.000 2.9333 0.126 0.287 0.027 0.000 3.0000 0.128 0.296 0.027 0.000 3.0667 0.129 0.304 0.027 0.000 3.1333 0.131 0.313 0.028 0.000 3.2000 0.132 0.322 0.028 0.000 3.2667 0.134 0.331 0.028 0.000 3.3333 0.135 0.340 0.029 0.000 3.4000 0.136 0.349 0.029 0.000 3.4667 0.138 0.358 0.029 0.000 3.5333 0.139 0.367 0.030 0.000 3.6000 0.141 0.376 0.030 0.000 3.6667 0.142 0.386 0.042 0.000 3.7333 0.144 0.396 0.048 0.000 3.8000 0.145 0.405 0.052 0.000 3.8667 0.147 0.415 0.055 0.000 3.9333 0.148 0.425 0.058 0.000 4.0000 0.150 0.435 0.061 0.000 4.0667 0.152 0.445 0.064 0.000 4.1333 0.153 0.455 0.066 0.000 4.2000 0.155 0.465 0.068 0.000 4.2667 0.156 0.476 0.071 0.000 4.3333 0.158 0.486 0.073 0.000 4.4000 0.159 0.497 0.075 0.000 4.4667 0.161 0.508 0.095 0.000 4.5333 0.162 0.518 0.104 0.000 4.6000 0.164 0.529 0.112 0.000 4.6667 0.166 0.540 0.118 0.000 4.7333 0.167 0.551 0.124 0.000 4.8000 0.169 0.563 0.130 0.000 4.8667 0.171 0.574 0.135 0.000 4.9333 0.172 0.585 0.140 0.000 5.0000 0.174 0.597 0.144 0.000 5.0667 0.175 0.609 0.697 0.000 5.1333 0.177 0.620 1.701 0.000 5.2000 0.179 0.632 2.998 0.000 5.2667 0.180 0.644 4.525 0.000 5.3333 0.182 0.656 6.242 0.000 5.4000 0.184 0.669 8.114 0.000 5.4667 0.185 0.681 10.10 0.000 5.5333 0.187 0.693 12.19 0.000 5.6000 0.189 0.706 14.32 0.000 5.6667 0.191 0.719 16.49 0.000 5.7333 0.192 0.732 18.63 0.000 5.8000 0.194 0.744 20.73 0.000 5.8667 0.196 0.757 22.75 0.000 5.9333 0.198 0.771 24.66 0.000 6.0000 0.199 0.784 26.44 0.000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 9 6.0667 0.201 0.797 28.05 0.000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 10 Bioretention 1 Bottom Length: 60.00 ft. Bottom Width: 5.00 ft. Material thickness of first layer: 1.5 Material type for first layer: SMMWW 12 in/hr Material thickness of second layer: 1 Material type for second layer: GRAVEL Material thickness of third layer: 0 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet): 0.5 Orifice Diameter (in.): 6 Offset (in.): 0 Flow Through Underdrain (ac-ft.): 187.463 Total Outflow (ac-ft.): 205.086 Percent Through Underdrain: 91.41 Discharge Structure Riser Height: 1 ft. Riser Diameter: 36 in. Element Flows To: Outlet 1 Outlet 2 Trapezoidal Pond 1 Bioretention Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0344 0.0000 0.0000 0.0000 0.0440 0.0339 0.0001 0.0000 0.0000 0.0879 0.0334 0.0003 0.0000 0.0000 0.1319 0.0328 0.0005 0.0000 0.0000 0.1758 0.0322 0.0006 0.0000 0.0000 0.2198 0.0317 0.0008 0.0000 0.0000 0.2637 0.0311 0.0010 0.0000 0.0000 0.3077 0.0306 0.0012 0.0000 0.0000 0.3516 0.0300 0.0014 0.0000 0.0000 0.3956 0.0295 0.0016 0.0000 0.0000 0.4396 0.0289 0.0018 0.0000 0.0000 0.4835 0.0284 0.0020 0.0000 0.0000 0.5275 0.0278 0.0022 0.0000 0.0000 0.5714 0.0273 0.0025 0.0000 0.0000 0.6154 0.0268 0.0027 0.0000 0.0000 0.6593 0.0262 0.0030 0.0000 0.0000 0.7033 0.0257 0.0033 0.0000 0.0000 0.7473 0.0252 0.0035 0.0000 0.0000 0.7912 0.0247 0.0038 0.0000 0.0000 0.8352 0.0241 0.0041 0.0000 0.0000 0.8791 0.0236 0.0044 0.0000 0.0000 0.9231 0.0231 0.0048 0.0000 0.0000 0.9670 0.0226 0.0051 0.0000 0.0000 1.0110 0.0221 0.0054 0.0000 0.0000 1.0549 0.0216 0.0057 0.0000 0.0000 1.0989 0.0211 0.0061 0.0000 0.0000 1.1429 0.0206 0.0065 0.0000 0.0000 1.1868 0.0201 0.0068 0.0000 0.0000 1.2308 0.0196 0.0072 0.0000 0.0000 1.2747 0.0192 0.0076 0.0000 0.0000 1.3187 0.0187 0.0080 0.0000 0.0000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 11 1.3626 0.0182 0.0084 0.0000 0.0000 1.4066 0.0177 0.0088 0.0000 0.0000 1.4505 0.0173 0.0093 0.0000 0.0000 1.4945 0.0168 0.0097 0.0000 0.0000 1.5385 0.0163 0.0101 0.0000 0.0000 1.5824 0.0159 0.0105 0.0000 0.0000 1.6264 0.0154 0.0110 0.0000 0.0000 1.6703 0.0149 0.0114 0.0000 0.0000 1.7143 0.0145 0.0118 0.0000 0.0000 1.7582 0.0140 0.0123 0.0000 0.0000 1.8022 0.0136 0.0128 0.0000 0.0000 1.8462 0.0131 0.0132 0.0000 0.0000 1.8901 0.0127 0.0137 0.0000 0.0000 1.9341 0.0123 0.0142 0.0000 0.0000 1.9780 0.0118 0.0147 0.0000 0.0000 2.0220 0.0114 0.0152 0.0000 0.0000 2.0659 0.0110 0.0157 0.0000 0.0000 2.1099 0.0106 0.0163 0.0000 0.0000 2.1538 0.0101 0.0168 0.0000 0.0000 2.1978 0.0097 0.0174 0.0000 0.0000 2.2418 0.0093 0.0179 0.0000 0.0000 2.2857 0.0089 0.0185 0.0000 0.0000 2.3297 0.0085 0.0191 0.0000 0.0000 2.3736 0.0081 0.0197 0.0000 0.0000 2.4176 0.0077 0.0203 0.0000 0.0000 2.4615 0.0073 0.0209 0.0000 0.0000 2.5000 0.0069 0.0214 0.0000 0.0000 Bioretention Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)To Amended(cfs)Infilt(cfs) 2.5000 0.0344 0.0214 0.0000 0.0208 0.0000 2.5440 0.0350 0.0230 0.0000 0.0208 0.0000 2.5879 0.0356 0.0245 0.0000 0.0221 0.0000 2.6319 0.0362 0.0261 0.0000 0.0227 0.0000 2.6758 0.0368 0.0277 0.0000 0.0233 0.0000 2.7198 0.0374 0.0293 0.0001 0.0239 0.0000 2.7637 0.0379 0.0310 0.0002 0.0245 0.0000 2.8077 0.0385 0.0327 0.0002 0.0251 0.0000 2.8516 0.0391 0.0344 0.0004 0.0257 0.0000 2.8956 0.0397 0.0361 0.0005 0.0263 0.0000 2.9396 0.0403 0.0379 0.0007 0.0269 0.0000 2.9835 0.0410 0.0397 0.0009 0.0275 0.0000 3.0275 0.0416 0.0415 0.0011 0.0282 0.0000 3.0714 0.0422 0.0433 0.0014 0.0288 0.0000 3.1154 0.0428 0.0452 0.0017 0.0294 0.0000 3.1593 0.0434 0.0471 0.0020 0.0300 0.0000 3.2033 0.0440 0.0490 0.0024 0.0306 0.0000 3.2473 0.0447 0.0509 0.0029 0.0312 0.0000 3.2912 0.0453 0.0529 0.0029 0.0318 0.0000 3.3352 0.0459 0.0549 0.0033 0.0324 0.0000 3.3791 0.0466 0.0570 0.0039 0.0330 0.0000 3.4231 0.0472 0.0590 0.0044 0.0337 0.0000 3.4670 0.0479 0.0611 0.0050 0.0343 0.0000 3.5110 0.0485 0.0632 0.0057 0.0347 0.0000 3.5549 0.0492 0.0654 0.0064 0.0347 0.0000 3.5989 0.0498 0.0675 0.0071 0.0347 0.0000 3.6429 0.0505 0.0698 0.0072 0.0347 0.0000 3.6868 0.0511 0.0720 0.0080 0.0347 0.0000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 12 3.7308 0.0518 0.0742 0.0089 0.0347 0.0000 3.7747 0.0525 0.0765 0.0098 0.0347 0.0000 3.8187 0.0531 0.0789 0.0108 0.0347 0.0000 3.8626 0.0538 0.0812 0.0118 0.0347 0.0000 3.9066 0.0545 0.0836 0.0129 0.0347 0.0000 3.9505 0.0552 0.0860 0.0137 0.0347 0.0000 3.9945 0.0558 0.0884 0.0141 0.0347 0.0000 4.0000 0.0559 0.0887 0.0153 0.0347 0.0000 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 13 Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Trapezoidal Pond 1 Bioretention 1 20231213 NorthDetentionPond 12/14/2023 9:59:52 AM Page 14 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 2.221 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 1.205 Total Impervious Area: 1.016 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.065299 5 year 0.102555 10 year 0.123668 25 year 0.146036 50 year 0.159878 100 year 0.17165 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.038606 5 year 0.063161 10 year 0.083933 25 year 0.116082 50 year 0.14483 100 year 0.178147 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.064 0.026 1950 0.080 0.044 1951 0.144 0.123 1952 0.045 0.024 1953 0.037 0.029 1954 0.056 0.029 1955 0.090 0.028 1956 0.071 0.064 1957 0.058 0.029 1958 0.065 0.030 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 15 1959 0.056 0.026 1960 0.097 0.084 1961 0.055 0.048 1962 0.034 0.023 1963 0.047 0.029 1964 0.062 0.030 1965 0.044 0.058 1966 0.042 0.028 1967 0.089 0.038 1968 0.055 0.028 1969 0.054 0.028 1970 0.045 0.030 1971 0.048 0.029 1972 0.107 0.075 1973 0.049 0.056 1974 0.053 0.030 1975 0.072 0.027 1976 0.052 0.029 1977 0.006 0.022 1978 0.045 0.038 1979 0.027 0.022 1980 0.101 0.100 1981 0.041 0.029 1982 0.078 0.059 1983 0.070 0.030 1984 0.043 0.025 1985 0.026 0.025 1986 0.113 0.045 1987 0.100 0.067 1988 0.040 0.025 1989 0.026 0.024 1990 0.209 0.103 1991 0.126 0.070 1992 0.049 0.045 1993 0.051 0.024 1994 0.017 0.021 1995 0.073 0.047 1996 0.153 0.122 1997 0.128 0.125 1998 0.029 0.024 1999 0.120 0.078 2000 0.050 0.030 2001 0.009 0.018 2002 0.055 0.053 2003 0.071 0.027 2004 0.091 0.098 2005 0.066 0.029 2006 0.077 0.061 2007 0.155 0.144 2008 0.200 0.110 2009 0.098 0.052 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.2093 0.1440 2 0.2004 0.1250 3 0.1554 0.1228 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 16 4 0.1530 0.1223 5 0.1438 0.1104 6 0.1279 0.1025 7 0.1260 0.0999 8 0.1199 0.0985 9 0.1132 0.0841 10 0.1071 0.0780 11 0.1015 0.0749 12 0.1001 0.0698 13 0.0984 0.0672 14 0.0972 0.0637 15 0.0914 0.0614 16 0.0897 0.0591 17 0.0888 0.0584 18 0.0800 0.0557 19 0.0780 0.0525 20 0.0773 0.0523 21 0.0726 0.0478 22 0.0715 0.0471 23 0.0714 0.0454 24 0.0706 0.0446 25 0.0699 0.0438 26 0.0656 0.0379 27 0.0649 0.0377 28 0.0641 0.0305 29 0.0617 0.0304 30 0.0576 0.0301 31 0.0563 0.0301 32 0.0557 0.0299 33 0.0554 0.0296 34 0.0553 0.0294 35 0.0549 0.0293 36 0.0542 0.0293 37 0.0528 0.0290 38 0.0517 0.0290 39 0.0506 0.0287 40 0.0505 0.0287 41 0.0486 0.0286 42 0.0486 0.0280 43 0.0478 0.0280 44 0.0469 0.0280 45 0.0454 0.0279 46 0.0453 0.0274 47 0.0447 0.0266 48 0.0442 0.0264 49 0.0432 0.0263 50 0.0425 0.0252 51 0.0406 0.0247 52 0.0395 0.0245 53 0.0366 0.0241 54 0.0341 0.0239 55 0.0289 0.0237 56 0.0274 0.0237 57 0.0258 0.0234 58 0.0256 0.0220 59 0.0170 0.0218 60 0.0091 0.0211 61 0.0062 0.0183 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 17 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 18 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0326 17562 11340 64 Pass 0.0339 16164 10908 67 Pass 0.0352 14970 10476 69 Pass 0.0365 13854 10066 72 Pass 0.0378 12810 9580 74 Pass 0.0391 11811 9221 78 Pass 0.0404 10898 8859 81 Pass 0.0416 10121 8498 83 Pass 0.0429 9383 8173 87 Pass 0.0442 8731 7661 87 Pass 0.0455 8143 7212 88 Pass 0.0468 7593 6855 90 Pass 0.0481 7058 6436 91 Pass 0.0494 6590 6079 92 Pass 0.0506 6145 5724 93 Pass 0.0519 5777 5324 92 Pass 0.0532 5431 4889 90 Pass 0.0545 5097 4502 88 Pass 0.0558 4808 4190 87 Pass 0.0571 4524 3901 86 Pass 0.0584 4252 3593 84 Pass 0.0596 4017 3328 82 Pass 0.0609 3782 3157 83 Pass 0.0622 3546 2986 84 Pass 0.0635 3337 2802 83 Pass 0.0648 3138 2614 83 Pass 0.0661 2950 2402 81 Pass 0.0673 2785 2147 77 Pass 0.0686 2597 1990 76 Pass 0.0699 2447 1779 72 Pass 0.0712 2304 1568 68 Pass 0.0725 2162 1394 64 Pass 0.0738 2025 1174 57 Pass 0.0751 1898 974 51 Pass 0.0763 1790 915 51 Pass 0.0776 1688 890 52 Pass 0.0789 1585 870 54 Pass 0.0802 1483 853 57 Pass 0.0815 1379 835 60 Pass 0.0828 1292 816 63 Pass 0.0841 1218 797 65 Pass 0.0853 1154 777 67 Pass 0.0866 1098 761 69 Pass 0.0879 1048 743 70 Pass 0.0892 997 727 72 Pass 0.0905 930 710 76 Pass 0.0918 883 687 77 Pass 0.0931 837 671 80 Pass 0.0943 789 650 82 Pass 0.0956 743 630 84 Pass 0.0969 713 589 82 Pass 0.0982 668 537 80 Pass 0.0995 630 496 78 Pass 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 19 0.1008 596 460 77 Pass 0.1020 567 430 75 Pass 0.1033 539 390 72 Pass 0.1046 497 351 70 Pass 0.1059 473 330 69 Pass 0.1072 437 310 70 Pass 0.1085 401 295 73 Pass 0.1098 370 278 75 Pass 0.1110 348 257 73 Pass 0.1123 323 242 74 Pass 0.1136 296 228 77 Pass 0.1149 275 212 77 Pass 0.1162 257 196 76 Pass 0.1175 235 183 77 Pass 0.1188 217 173 79 Pass 0.1200 198 159 80 Pass 0.1213 180 143 79 Pass 0.1226 158 121 76 Pass 0.1239 145 106 73 Pass 0.1252 130 91 70 Pass 0.1265 119 86 72 Pass 0.1277 109 82 75 Pass 0.1290 97 75 77 Pass 0.1303 91 69 75 Pass 0.1316 82 63 76 Pass 0.1329 76 60 78 Pass 0.1342 69 55 79 Pass 0.1355 61 51 83 Pass 0.1367 54 47 87 Pass 0.1380 48 42 87 Pass 0.1393 41 38 92 Pass 0.1406 38 34 89 Pass 0.1419 33 30 90 Pass 0.1432 27 12 44 Pass 0.1445 22 0 0 Pass 0.1457 21 0 0 Pass 0.1470 20 0 0 Pass 0.1483 19 0 0 Pass 0.1496 17 0 0 Pass 0.1509 14 0 0 Pass 0.1522 12 0 0 Pass 0.1535 900Pass 0.1547 400Pass 0.1560 300Pass 0.1573 300Pass 0.1586 300Pass 0.1599 300Pass 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 20 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. 20231213 NorthDetentionPond 12/14/2023 10:00:23 AM Page 21 LID Report 20231213 NorthDetentionPond 12/14/2023 10:00:44 AM Page 22 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20231213 NorthDetentionPond 12/14/2023 10:00:44 AM Page 23 Appendix Predeveloped Schematic 20231213 NorthDetentionPond 12/14/2023 10:00:45 AM Page 24 Mitigated Schematic 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 25 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231213 NorthDetentionPond.wdm MESSU 25 Pre20231213 NorthDetentionPond.MES 27 Pre20231213 NorthDetentionPond.L61 28 Pre20231213 NorthDetentionPond.L62 30 POC20231213 NorthDetentionPond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 South Half MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 26 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 27 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Half*** PERLND 10 2.221 COPY 501 12 PERLND 10 2.221 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 28 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 29 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231213 NorthDetentionPond.wdm MESSU 25 Mit20231213 NorthDetentionPond.MES 27 Mit20231213 NorthDetentionPond.L61 28 Mit20231213 NorthDetentionPond.L62 30 POC20231213 NorthDetentionPond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 4 RCHRES 1 RCHRES 2 RCHRES 3 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Trapezoidal Pond 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 30 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 4 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 4 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 31 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 4 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** North Pond Treat*** PERLND 16 1.205 RCHRES 1 2 PERLND 16 1.205 RCHRES 1 3 IMPLND 1 0.673 RCHRES 1 5 North Pond Detain*** IMPLND 4 0.343 RCHRES 3 5 ******Routing****** RCHRES 2 1 RCHRES 3 6 RCHRES 2 COPY 1 16 RCHRES 1 1 RCHRES 3 7 RCHRES 1 COPY 1 17 RCHRES 1 1 RCHRES 2 8 IMPLND 4 0.343 COPY 1 15 RCHRES 3 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Surface retentio-025 2 1 1 1 28 0 1 2 Bioretention 1 1 1 1 1 28 0 1 3 Trapezoidal Pond-021 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 3 1 0 0 0 0 0 0 0 0 0 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 32 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 3 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 3 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.0 0.0 2 2 0.01 0.0 0.0 0.0 0.0 3 3 0.02 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 3 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 3 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.071625 0.000000 0.000000 0.066667 0.072722 0.004812 0.000000 0.133333 0.073826 0.009696 0.000000 0.200000 0.074937 0.014655 0.000000 0.266667 0.076055 0.019688 0.000000 0.333333 0.077181 0.024796 0.000000 0.400000 0.078314 0.029979 0.000000 0.466667 0.079455 0.035238 0.000000 0.533333 0.080602 0.040573 0.003171 0.600000 0.081758 0.045985 0.005492 0.666667 0.082920 0.051475 0.007090 0.733333 0.084090 0.057042 0.008389 0.800000 0.085267 0.062687 0.009513 0.866667 0.086452 0.068411 0.010517 0.933333 0.087644 0.074214 0.011433 1.000000 0.088843 0.080097 0.012281 1.066667 0.090050 0.086060 0.013074 1.133333 0.091264 0.092104 0.013821 1.200000 0.092485 0.098229 0.014531 1.266667 0.093713 0.104435 0.015207 1.333333 0.094949 0.110724 0.015854 1.400000 0.096193 0.117096 0.016476 1.466667 0.097444 0.123550 0.017076 1.533333 0.098702 0.130088 0.017655 1.600000 0.099967 0.136711 0.018215 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 33 1.666667 0.101240 0.143418 0.018759 1.733333 0.102520 0.150209 0.019288 1.800000 0.103807 0.157087 0.019802 1.866667 0.105102 0.164051 0.020303 1.933333 0.106404 0.171101 0.020793 2.000000 0.107713 0.178238 0.021271 2.066667 0.109030 0.185463 0.021738 2.133333 0.110354 0.192776 0.022196 2.200000 0.111686 0.200177 0.022645 2.266667 0.113025 0.207667 0.023084 2.333333 0.114371 0.215247 0.023516 2.400000 0.115725 0.222917 0.023940 2.466667 0.117085 0.230678 0.024356 2.533333 0.118454 0.238529 0.024765 2.600000 0.119829 0.246472 0.025168 2.666667 0.121212 0.254506 0.025564 2.733333 0.122602 0.262633 0.025955 2.800000 0.124000 0.270854 0.026339 2.866667 0.125405 0.279167 0.026718 2.933333 0.126817 0.287574 0.027092 3.000000 0.128237 0.296076 0.027461 3.066667 0.129664 0.304673 0.027824 3.133333 0.131098 0.313365 0.028183 3.200000 0.132540 0.322153 0.028538 3.266667 0.133989 0.331037 0.028888 3.333333 0.135445 0.340018 0.029234 3.400000 0.136909 0.349097 0.029576 3.466667 0.138380 0.358273 0.029914 3.533333 0.139859 0.367548 0.030248 3.600000 0.141344 0.376921 0.030579 3.666667 0.142837 0.386394 0.042747 3.733333 0.144338 0.395966 0.047976 3.800000 0.145846 0.405639 0.052059 3.866667 0.147361 0.415413 0.055549 3.933333 0.148883 0.425288 0.058659 4.000000 0.150413 0.435264 0.061497 4.066667 0.151950 0.445343 0.064129 4.133333 0.153495 0.455524 0.066597 4.200000 0.155047 0.465809 0.068931 4.266667 0.156606 0.476198 0.071152 4.333333 0.158173 0.486690 0.073277 4.400000 0.159747 0.497288 0.075318 4.466667 0.161328 0.507990 0.095222 4.533333 0.162916 0.518798 0.104553 4.600000 0.164512 0.529712 0.112096 4.666667 0.166116 0.540733 0.118691 4.733333 0.167726 0.551861 0.124665 4.800000 0.169344 0.563097 0.130189 4.866667 0.170970 0.574441 0.135365 4.933333 0.172602 0.585893 0.140258 5.000000 0.174242 0.597455 0.144917 5.066667 0.175890 0.609126 0.697258 5.133333 0.177545 0.620907 1.701919 5.200000 0.179207 0.632799 2.998546 5.266667 0.180876 0.644802 4.525863 5.333333 0.182553 0.656916 6.242662 5.400000 0.184237 0.669142 8.114293 5.466667 0.185928 0.681481 10.10796 5.533333 0.187627 0.693933 12.19085 5.600000 0.189333 0.706498 14.32945 5.666667 0.191047 0.719178 16.48958 5.733333 0.192768 0.731971 18.63679 5.800000 0.194496 0.744880 20.73704 5.866667 0.196231 0.757904 22.75762 5.933333 0.197974 0.771045 24.66826 6.000000 0.199725 0.784301 26.44232 END FTABLE 3 FTABLE 2 58 4 Depth Area Volume Outflow1 Velocity Travel Time*** 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 34 (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.034435 0.000000 0.000000 0.043956 0.033933 0.000142 0.000000 0.087912 0.033362 0.000293 0.000000 0.131868 0.032795 0.000451 0.000000 0.175824 0.032230 0.000618 0.000000 0.219780 0.031669 0.000792 0.000095 0.263736 0.031111 0.000975 0.000159 0.307692 0.030556 0.001167 0.000246 0.351648 0.030005 0.001366 0.000359 0.395604 0.029456 0.001574 0.000498 0.439560 0.028911 0.001791 0.000668 0.483516 0.028369 0.002016 0.000870 0.527473 0.027830 0.002249 0.001106 0.571429 0.027294 0.002492 0.001378 0.615385 0.026762 0.002743 0.001687 0.659341 0.026233 0.003003 0.002036 0.703297 0.025707 0.003271 0.002426 0.747253 0.025184 0.003549 0.002858 0.791209 0.024664 0.003836 0.002932 0.835165 0.024148 0.004132 0.003334 0.879121 0.023634 0.004437 0.003855 0.923077 0.023124 0.004751 0.004423 0.967033 0.022617 0.005074 0.005039 1.010989 0.022114 0.005407 0.005704 1.054945 0.021613 0.005749 0.006420 1.098901 0.021116 0.006100 0.007114 1.142857 0.020622 0.006461 0.007188 1.186813 0.020131 0.006832 0.008008 1.230769 0.019643 0.007212 0.008883 1.274725 0.019158 0.007602 0.009812 1.318681 0.018677 0.008002 0.010797 1.362637 0.018199 0.008412 0.011840 1.406593 0.017724 0.008831 0.012940 1.450549 0.017252 0.009260 0.013651 1.494505 0.016783 0.009700 0.014098 1.538462 0.016318 0.010108 0.015315 1.582418 0.015856 0.010525 0.016590 1.626374 0.015397 0.010952 0.017923 1.670330 0.014941 0.011387 0.019309 1.714286 0.014488 0.011833 0.020713 1.758242 0.014039 0.012287 0.034722 1.802198 0.013593 0.012751 0.034722 1.846154 0.013150 0.013225 0.034722 1.890110 0.012710 0.013709 0.034722 1.934066 0.012273 0.014202 0.034722 1.978022 0.011840 0.014704 0.034722 2.021978 0.011409 0.015217 0.034722 2.065934 0.010982 0.015739 0.034722 2.109890 0.010558 0.016272 0.034722 2.153846 0.010138 0.016814 0.034722 2.197802 0.009720 0.017366 0.034722 2.241758 0.009306 0.017929 0.034722 2.285714 0.008895 0.018502 0.034722 2.329670 0.008487 0.019084 0.034722 2.373626 0.008082 0.019677 0.034722 2.417582 0.007681 0.020281 0.034722 2.461538 0.007282 0.020895 0.034722 2.500000 0.006887 0.022158 0.034722 END FTABLE 2 FTABLE 1 36 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.006887 0.000000 0.000000 0.000000 0.043956 0.035012 0.001526 0.000000 0.020833 0.087912 0.035592 0.003078 0.000000 0.022054 0.131868 0.036175 0.004655 0.000000 0.022665 0.175824 0.036762 0.006258 0.000000 0.023275 0.219780 0.037351 0.007887 0.000000 0.023886 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 35 0.263736 0.037944 0.009542 0.000000 0.024496 0.307692 0.038540 0.011223 0.000000 0.025107 0.351648 0.039139 0.012930 0.000000 0.025717 0.395604 0.039741 0.014664 0.000000 0.026328 0.439560 0.040347 0.016424 0.000000 0.026938 0.483516 0.040955 0.018211 0.000000 0.027549 0.527473 0.041567 0.020025 0.000000 0.028159 0.571429 0.042182 0.021865 0.000000 0.028770 0.615385 0.042801 0.023733 0.000000 0.029380 0.659341 0.043422 0.025628 0.000000 0.029991 0.703297 0.044047 0.027550 0.000000 0.030601 0.747253 0.044675 0.029500 0.000000 0.031212 0.791209 0.045306 0.031478 0.000000 0.031822 0.835165 0.045940 0.033483 0.000000 0.032433 0.879121 0.046578 0.035517 0.000000 0.033043 0.923077 0.047218 0.037578 0.000000 0.033654 0.967033 0.047862 0.039668 0.000000 0.034264 1.010989 0.048509 0.041786 0.036700 0.034722 1.054945 0.049159 0.043932 0.410004 0.034722 1.098901 0.049813 0.046108 0.989555 0.034722 1.142857 0.050469 0.048312 1.716821 0.034722 1.186813 0.051129 0.050545 2.565262 0.034722 1.230769 0.051792 0.052807 3.517872 0.034722 1.274725 0.052458 0.055098 4.561769 0.034722 1.318681 0.053128 0.057418 5.686076 0.034722 1.362637 0.053800 0.059768 6.880892 0.034722 1.406593 0.054476 0.062148 8.136751 0.034722 1.450549 0.055155 0.064558 9.444309 0.034722 1.494505 0.055837 0.066997 10.79418 0.034722 1.500000 0.055923 0.067304 12.17685 0.034722 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 1 EVAP ENGL 0.5 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 3 HYDR RO 1 1 1 WDM 1006 FLOW ENGL REPL RCHRES 3 HYDR STAGE 1 1 1 WDM 1007 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 36 MASS-LINK 6 RCHRES ROFLOW RCHRES INFLOW END MASS-LINK 6 MASS-LINK 7 RCHRES OFLOW OVOL 1 RCHRES INFLOW IVOL END MASS-LINK 7 MASS-LINK 8 RCHRES OFLOW OVOL 2 RCHRES INFLOW IVOL END MASS-LINK 8 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN 20231213 NorthDetentionPond 12/14/2023 10:00:47 AM Page 37 Predeveloped HSPF Message File 20231213 NorthDetentionPond 12/14/2023 10:00:48 AM Page 38 Mitigated HSPF Message File 20231213 NorthDetentionPond 12/14/2023 10:00:48 AM Page 39 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 2 General Model Information WWHM2012 Project Name: 20231204 SouthDetentionPond Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/16/2023 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2023/03/31 Version: 4.2.19 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 3 Landuse Basin Data Predeveloped Land Use South Half Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 3.252 Pervious Total 3.252 Impervious Land Use acre Impervious Total 0 Basin Total 3.252 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 4 Mitigated Land Use South Half Detain Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 1.965 Pervious Total 1.965 Impervious Land Use acre ROADS FLAT 1.187 Impervious Total 1.187 Basin Total 3.152 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 5 Undetained Area Bypass: Yes GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.1 Pervious Total 0.1 Impervious Land Use acre Impervious Total 0 Basin Total 0.1 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 6 Routing Elements Predeveloped Routing 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 7 Mitigated Routing Trapezoidal Pond 1 Bottom Length: 98.00 ft. Bottom Width: 45.00 ft. Depth: 6 ft. Volume at riser head: 0.7868 acre-feet. Side slope 1: 3 To 1 Side slope 2: 3 To 1 Side slope 3: 3 To 1 Side slope 4: 3 To 1 Discharge Structure Riser Height: 5 ft. Riser Diameter: 36 in. Orifice 1 Diameter: 0.900 in. Elevation:0.5 ft. Orifice 2 Diameter: 1.250 in. Elevation:3.5 ft. Orifice 3 Diameter: 2.200 in. Elevation:4.4 ft. Element Flows To: Outlet 1 Outlet 2 Pond Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.101 0.000 0.000 0.000 0.0667 0.102 0.006 0.000 0.000 0.1333 0.103 0.013 0.000 0.000 0.2000 0.105 0.020 0.000 0.000 0.2667 0.106 0.027 0.000 0.000 0.3333 0.107 0.034 0.000 0.000 0.4000 0.109 0.042 0.000 0.000 0.4667 0.110 0.049 0.000 0.000 0.5333 0.112 0.056 0.004 0.000 0.6000 0.113 0.064 0.007 0.000 0.6667 0.114 0.072 0.009 0.000 0.7333 0.116 0.079 0.010 0.000 0.8000 0.117 0.087 0.012 0.000 0.8667 0.118 0.095 0.013 0.000 0.9333 0.120 0.103 0.014 0.000 1.0000 0.121 0.111 0.015 0.000 1.0667 0.123 0.119 0.016 0.000 1.1333 0.124 0.127 0.017 0.000 1.2000 0.126 0.136 0.018 0.000 1.2667 0.127 0.144 0.019 0.000 1.3333 0.129 0.153 0.020 0.000 1.4000 0.130 0.161 0.020 0.000 1.4667 0.131 0.170 0.021 0.000 1.5333 0.133 0.179 0.022 0.000 1.6000 0.134 0.188 0.023 0.000 1.6667 0.136 0.197 0.023 0.000 1.7333 0.137 0.206 0.024 0.000 1.8000 0.139 0.215 0.025 0.000 1.8667 0.140 0.225 0.025 0.000 1.9333 0.142 0.234 0.026 0.000 2.0000 0.143 0.244 0.026 0.000 2.0667 0.145 0.253 0.027 0.000 2.1333 0.147 0.263 0.028 0.000 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 8 2.2000 0.148 0.273 0.028 0.000 2.2667 0.150 0.283 0.029 0.000 2.3333 0.151 0.293 0.029 0.000 2.4000 0.153 0.303 0.030 0.000 2.4667 0.154 0.313 0.030 0.000 2.5333 0.156 0.324 0.031 0.000 2.6000 0.158 0.334 0.031 0.000 2.6667 0.159 0.345 0.032 0.000 2.7333 0.161 0.355 0.032 0.000 2.8000 0.162 0.366 0.033 0.000 2.8667 0.164 0.377 0.033 0.000 2.9333 0.166 0.388 0.034 0.000 3.0000 0.167 0.399 0.034 0.000 3.0667 0.169 0.411 0.035 0.000 3.1333 0.171 0.422 0.035 0.000 3.2000 0.172 0.433 0.036 0.000 3.2667 0.174 0.445 0.036 0.000 3.3333 0.176 0.457 0.037 0.000 3.4000 0.177 0.468 0.037 0.000 3.4667 0.179 0.480 0.037 0.000 3.5333 0.181 0.492 0.046 0.000 3.6000 0.182 0.505 0.052 0.000 3.6667 0.184 0.517 0.056 0.000 3.7333 0.186 0.529 0.060 0.000 3.8000 0.188 0.542 0.063 0.000 3.8667 0.189 0.554 0.066 0.000 3.9333 0.191 0.567 0.068 0.000 4.0000 0.193 0.580 0.071 0.000 4.0667 0.195 0.593 0.073 0.000 4.1333 0.196 0.606 0.075 0.000 4.2000 0.198 0.619 0.077 0.000 4.2667 0.200 0.632 0.079 0.000 4.3333 0.202 0.646 0.081 0.000 4.4000 0.203 0.659 0.083 0.000 4.4667 0.205 0.673 0.119 0.000 4.5333 0.207 0.687 0.135 0.000 4.6000 0.209 0.700 0.147 0.000 4.6667 0.211 0.714 0.158 0.000 4.7333 0.213 0.729 0.168 0.000 4.8000 0.214 0.743 0.177 0.000 4.8667 0.216 0.757 0.185 0.000 4.9333 0.218 0.772 0.193 0.000 5.0000 0.220 0.786 0.200 0.000 5.0667 0.222 0.801 0.755 0.000 5.1333 0.224 0.816 1.762 0.000 5.2000 0.226 0.831 3.061 0.000 5.2667 0.227 0.846 4.590 0.000 5.3333 0.229 0.861 6.309 0.000 5.4000 0.231 0.877 8.183 0.000 5.4667 0.233 0.892 10.17 0.000 5.5333 0.235 0.908 12.26 0.000 5.6000 0.237 0.924 14.40 0.000 5.6667 0.239 0.940 16.56 0.000 5.7333 0.241 0.956 18.71 0.000 5.8000 0.243 0.972 20.81 0.000 5.8667 0.245 0.988 22.83 0.000 5.9333 0.247 1.004 24.75 0.000 6.0000 0.249 1.021 26.52 0.000 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 9 6.0667 0.251 1.038 28.14 0.000 20231204 SouthDetentionPond 12/16/2023 5:31:53 PM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 3.252 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 2.065 Total Impervious Area: 1.187 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.095612 5 year 0.150162 10 year 0.181076 25 year 0.213827 50 year 0.234094 100 year 0.251331 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.058573 5 year 0.097339 10 year 0.129806 25 year 0.179528 50 year 0.223516 100 year 0.274013 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.094 0.041 1950 0.117 0.070 1951 0.211 0.189 1952 0.066 0.033 1953 0.054 0.052 1954 0.082 0.048 1955 0.131 0.039 1956 0.105 0.081 1957 0.084 0.040 1958 0.095 0.059 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 11 1959 0.082 0.037 1960 0.142 0.140 1961 0.080 0.071 1962 0.050 0.032 1963 0.069 0.051 1964 0.090 0.063 1965 0.065 0.078 1966 0.062 0.039 1967 0.130 0.060 1968 0.081 0.039 1969 0.079 0.039 1970 0.065 0.059 1971 0.070 0.048 1972 0.157 0.134 1973 0.071 0.075 1974 0.077 0.056 1975 0.105 0.039 1976 0.076 0.040 1977 0.009 0.028 1978 0.066 0.066 1979 0.040 0.030 1980 0.149 0.157 1981 0.059 0.049 1982 0.114 0.081 1983 0.102 0.055 1984 0.063 0.034 1985 0.038 0.033 1986 0.166 0.070 1987 0.147 0.087 1988 0.058 0.034 1989 0.038 0.033 1990 0.306 0.160 1991 0.185 0.104 1992 0.071 0.066 1993 0.074 0.034 1994 0.025 0.029 1995 0.106 0.071 1996 0.224 0.186 1997 0.187 0.180 1998 0.042 0.035 1999 0.176 0.135 2000 0.074 0.050 2001 0.013 0.024 2002 0.081 0.074 2003 0.103 0.037 2004 0.134 0.149 2005 0.096 0.040 2006 0.113 0.080 2007 0.227 0.230 2008 0.293 0.168 2009 0.144 0.076 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.3065 0.2302 2 0.2935 0.1888 3 0.2275 0.1862 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 12 4 0.2240 0.1799 5 0.2105 0.1678 6 0.1873 0.1602 7 0.1845 0.1572 8 0.1756 0.1487 9 0.1657 0.1397 10 0.1568 0.1345 11 0.1486 0.1341 12 0.1466 0.1042 13 0.1441 0.0870 14 0.1424 0.0807 15 0.1338 0.0806 16 0.1314 0.0795 17 0.1300 0.0780 18 0.1171 0.0758 19 0.1142 0.0755 20 0.1132 0.0736 21 0.1063 0.0714 22 0.1047 0.0713 23 0.1046 0.0703 24 0.1033 0.0699 25 0.1024 0.0665 26 0.0960 0.0660 27 0.0951 0.0627 28 0.0939 0.0602 29 0.0903 0.0589 30 0.0844 0.0586 31 0.0824 0.0565 32 0.0815 0.0553 33 0.0811 0.0518 34 0.0810 0.0506 35 0.0803 0.0495 36 0.0793 0.0492 37 0.0773 0.0482 38 0.0757 0.0478 39 0.0741 0.0405 40 0.0739 0.0402 41 0.0712 0.0401 42 0.0712 0.0397 43 0.0700 0.0394 44 0.0686 0.0392 45 0.0664 0.0391 46 0.0663 0.0390 47 0.0654 0.0389 48 0.0647 0.0371 49 0.0632 0.0366 50 0.0622 0.0351 51 0.0594 0.0345 52 0.0578 0.0338 53 0.0537 0.0336 54 0.0500 0.0333 55 0.0424 0.0332 56 0.0401 0.0328 57 0.0377 0.0318 58 0.0375 0.0302 59 0.0249 0.0288 60 0.0133 0.0284 61 0.0090 0.0237 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 13 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 14 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0478 17554 15374 87 Pass 0.0497 16164 14476 89 Pass 0.0516 14968 13781 92 Pass 0.0535 13849 13143 94 Pass 0.0553 12810 12333 96 Pass 0.0572 11809 11541 97 Pass 0.0591 10900 10806 99 Pass 0.0610 10121 10072 99 Pass 0.0629 9383 9315 99 Pass 0.0647 8729 8620 98 Pass 0.0666 8143 7886 96 Pass 0.0685 7593 7257 95 Pass 0.0704 7060 6438 91 Pass 0.0723 6590 5696 86 Pass 0.0741 6147 5097 82 Pass 0.0760 5775 4436 76 Pass 0.0779 5431 3938 72 Pass 0.0798 5097 3431 67 Pass 0.0817 4808 2975 61 Pass 0.0836 4524 2650 58 Pass 0.0854 4252 2199 51 Pass 0.0873 4017 1730 43 Pass 0.0892 3782 1648 43 Pass 0.0911 3546 1585 44 Pass 0.0930 3337 1522 45 Pass 0.0948 3138 1473 46 Pass 0.0967 2950 1433 48 Pass 0.0986 2785 1397 50 Pass 0.1005 2603 1370 52 Pass 0.1024 2451 1339 54 Pass 0.1043 2310 1300 56 Pass 0.1061 2162 1276 59 Pass 0.1080 2026 1256 61 Pass 0.1099 1898 1232 64 Pass 0.1118 1791 1213 67 Pass 0.1137 1693 1189 70 Pass 0.1155 1590 1169 73 Pass 0.1174 1483 1149 77 Pass 0.1193 1380 1126 81 Pass 0.1212 1294 1101 85 Pass 0.1231 1225 1074 87 Pass 0.1250 1155 1036 89 Pass 0.1268 1098 1001 91 Pass 0.1287 1048 962 91 Pass 0.1306 997 933 93 Pass 0.1325 930 903 97 Pass 0.1344 884 858 97 Pass 0.1362 838 831 99 Pass 0.1381 789 800 101 Pass 0.1400 743 759 102 Pass 0.1419 716 721 100 Pass 0.1438 671 673 100 Pass 0.1457 633 635 100 Pass 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 15 0.1475 596 600 100 Pass 0.1494 565 561 99 Pass 0.1513 540 532 98 Pass 0.1532 497 497 100 Pass 0.1551 473 462 97 Pass 0.1569 435 426 97 Pass 0.1588 399 369 92 Pass 0.1607 366 319 87 Pass 0.1626 348 304 87 Pass 0.1645 323 286 88 Pass 0.1664 296 267 90 Pass 0.1682 272 246 90 Pass 0.1701 256 228 89 Pass 0.1720 235 214 91 Pass 0.1739 217 194 89 Pass 0.1758 198 181 91 Pass 0.1776 180 161 89 Pass 0.1795 158 143 90 Pass 0.1814 145 128 88 Pass 0.1833 130 117 90 Pass 0.1852 119 101 84 Pass 0.1871 109 81 74 Pass 0.1889 97 64 65 Pass 0.1908 91 60 65 Pass 0.1927 82 56 68 Pass 0.1946 76 52 68 Pass 0.1965 69 47 68 Pass 0.1983 61 43 70 Pass 0.2002 54 39 72 Pass 0.2021 48 35 72 Pass 0.2040 41 31 75 Pass 0.2059 38 16 42 Pass 0.2078 33 8 24 Pass 0.2096 27 7 25 Pass 0.2115 22 7 31 Pass 0.2134 21 6 28 Pass 0.2153 20 6 30 Pass 0.2172 19 5 26 Pass 0.2190 17 5 29 Pass 0.2209 14 5 35 Pass 0.2228 12 4 33 Pass 0.2247 9 3 33 Pass 0.2266 4 2 50 Pass 0.2284 3 1 33 Pass 0.2303 300Pass 0.2322 300Pass 0.2341 300Pass 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 16 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. 20231204 SouthDetentionPond 12/16/2023 5:32:17 PM Page 17 LID Report 20231204 SouthDetentionPond 12/16/2023 5:32:42 PM Page 18 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20231204 SouthDetentionPond 12/16/2023 5:32:42 PM Page 19 Appendix Predeveloped Schematic 20231204 SouthDetentionPond 12/16/2023 5:32:43 PM Page 20 Mitigated Schematic 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 21 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231204 SouthDetentionPond.wdm MESSU 25 Pre20231204 SouthDetentionPond.MES 27 Pre20231204 SouthDetentionPond.L61 28 Pre20231204 SouthDetentionPond.L62 30 POC20231204 SouthDetentionPond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 South Half MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 22 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 23 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Half*** PERLND 10 3.252 COPY 501 12 PERLND 10 3.252 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 24 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 25 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231204 SouthDetentionPond.wdm MESSU 25 Mit20231204 SouthDetentionPond.MES 27 Mit20231204 SouthDetentionPond.L61 28 Mit20231204 SouthDetentionPond.L62 30 POC20231204 SouthDetentionPond1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 RCHRES 1 COPY 1 COPY 501 COPY 601 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Trapezoidal Pond 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 601 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 26 <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 27 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Half Detain*** PERLND 16 1.965 RCHRES 1 2 PERLND 16 1.965 RCHRES 1 3 IMPLND 1 1.187 RCHRES 1 5 Undetained Area*** PERLND 16 0.1 COPY 501 12 PERLND 16 0.1 COPY 601 12 PERLND 16 0.1 COPY 501 13 PERLND 16 0.1 COPY 601 13 ******Routing****** PERLND 16 1.965 COPY 1 12 IMPLND 1 1.187 COPY 1 15 PERLND 16 1.965 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Trapezoidal Pond-021 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 28 * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.02 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.101240 0.000000 0.000000 0.066667 0.102556 0.006793 0.000000 0.133333 0.103881 0.013674 0.000000 0.200000 0.105212 0.020644 0.000000 0.266667 0.106551 0.027703 0.000000 0.333333 0.107897 0.034851 0.000000 0.400000 0.109251 0.042090 0.000000 0.466667 0.110612 0.049418 0.000000 0.533333 0.111980 0.056838 0.004013 0.600000 0.113355 0.064349 0.006951 0.666667 0.114738 0.071952 0.008974 0.733333 0.116129 0.079648 0.010618 0.800000 0.117526 0.087436 0.012039 0.866667 0.118931 0.095318 0.013310 0.933333 0.120343 0.103294 0.014470 1.000000 0.121763 0.111364 0.015543 1.066667 0.123190 0.119529 0.016547 1.133333 0.124624 0.127790 0.017493 1.200000 0.126066 0.136146 0.018390 1.266667 0.127515 0.144599 0.019246 1.333333 0.128972 0.153148 0.020066 1.400000 0.130435 0.161795 0.020853 1.466667 0.131906 0.170540 0.021611 1.533333 0.133385 0.179383 0.022344 1.600000 0.134871 0.188325 0.023054 1.666667 0.136364 0.197366 0.023742 1.733333 0.137864 0.206507 0.024411 1.800000 0.139372 0.215748 0.025062 1.866667 0.140887 0.225090 0.025697 1.933333 0.142410 0.234533 0.026316 2.000000 0.143939 0.244078 0.026921 2.066667 0.145477 0.253726 0.027513 2.133333 0.147021 0.263475 0.028092 2.200000 0.148573 0.273329 0.028659 2.266667 0.150132 0.283285 0.029216 2.333333 0.151699 0.293346 0.029762 2.400000 0.153273 0.303512 0.030298 2.466667 0.154854 0.313783 0.030825 2.533333 0.156443 0.324160 0.031344 2.600000 0.158039 0.334642 0.031853 2.666667 0.159642 0.345232 0.032355 2.733333 0.161253 0.355928 0.032849 2.800000 0.162871 0.366732 0.033336 2.866667 0.164496 0.377645 0.033815 2.933333 0.166129 0.388665 0.034288 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 29 3.000000 0.167769 0.399795 0.034755 3.066667 0.169416 0.411035 0.035215 3.133333 0.171071 0.422384 0.035669 3.200000 0.172733 0.433844 0.036118 3.266667 0.174402 0.445416 0.036561 3.333333 0.176079 0.457098 0.036999 3.400000 0.177763 0.468893 0.037432 3.466667 0.179455 0.480800 0.037860 3.533333 0.181153 0.492821 0.046024 3.600000 0.182860 0.504954 0.052110 3.666667 0.184573 0.517202 0.056425 3.733333 0.186294 0.529564 0.060006 3.800000 0.188022 0.542041 0.063154 3.866667 0.189758 0.554634 0.066007 3.933333 0.191500 0.567343 0.068641 4.000000 0.193251 0.580168 0.071105 4.066667 0.195008 0.593110 0.073431 4.133333 0.196773 0.606169 0.075642 4.200000 0.198545 0.619346 0.077756 4.266667 0.200325 0.632642 0.079786 4.333333 0.202112 0.646057 0.081743 4.400000 0.203906 0.659591 0.083634 4.466667 0.205708 0.673244 0.119379 4.533333 0.207517 0.687019 0.135206 4.600000 0.209333 0.700914 0.147717 4.666667 0.211157 0.714930 0.158492 4.733333 0.212988 0.729068 0.168145 4.800000 0.214826 0.743329 0.176993 4.866667 0.216672 0.757712 0.185225 4.933333 0.218525 0.772218 0.192964 5.000000 0.220386 0.786849 0.200296 5.066667 0.222253 0.801603 0.755166 5.133333 0.224129 0.816483 1.762233 5.200000 0.226011 0.831487 3.061162 5.266667 0.227901 0.846618 4.590686 5.333333 0.229798 0.861875 6.309611 5.400000 0.231702 0.877258 8.183293 5.466667 0.233614 0.892768 10.17895 5.533333 0.235534 0.908407 12.26376 5.600000 0.237460 0.924173 14.40423 5.666667 0.239394 0.940068 16.56619 5.733333 0.241335 0.956093 18.71517 5.800000 0.243284 0.972247 20.81715 5.866667 0.245240 0.988531 22.83942 5.933333 0.247203 1.004945 24.75172 6.000000 0.249174 1.021491 26.52739 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1006 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1007 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL END EXT TARGETS MASS-LINK 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 30 <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 31 Predeveloped HSPF Message File 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 32 Mitigated HSPF Message File 20231204 SouthDetentionPond 12/16/2023 5:32:45 PM Page 33 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 2 General Model Information Project Name: 20231218 RoadDetentionModules Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/18/2023 Gage: Seatac Data Start: 1948/10/01 00:00 Data End: 2009/09/30 00:00 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2021/08/18 Version: 4.2.18 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 3 Landuse Basin Data Predeveloped Land Use Road Detain Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 1.048 Pervious Total 1.048 Impervious Land Use acre Impervious Total 0 Basin Total 1.048 Element Flows To: Surface Interflow Groundwater 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 4 Mitigated Land Use Road Detain Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.145 Pervious Total 0.145 Impervious Land Use acre ROADS FLAT 0.687 SIDEWALKS FLAT 0.216 Impervious Total 0.903 Basin Total 1.048 Element Flows To: Surface Interflow Groundwater Gravel Trench Bed 1 Gravel Trench Bed 1 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 5 Routing Elements Predeveloped Routing 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 6 Mitigated Routing Gravel Trench Bed 1 Bottom Length: 135.00 ft. Bottom Width: 30.00 ft. Trench bottom slope 1: 0 To 1 Trench Left side slope 0: 0 To 1 Trench right side slope 2: 0 To 1 Material thickness of first layer: 6 Pour Space of material for first layer: 0.97 Material thickness of second layer: 0 Pour Space of material for second layer: 0 Material thickness of third layer: 0 Pour Space of material for third layer: 0 Discharge Structure Riser Height: 5.95 ft. Riser Diameter: 36 in. Orifice 1 Diameter: 0.6 in. Elevation:0.5 ft. Orifice 2 Diameter: 0.6 in. Elevation:3.1 ft. Orifice 3 Diameter: 1 in. Elevation:5.2 ft. Element Flows To: Outlet 1 Outlet 2 Gravel Trench Bed Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.093 0.000 0.000 0.000 0.0667 0.093 0.006 0.000 0.000 0.1333 0.093 0.012 0.000 0.000 0.2000 0.093 0.018 0.000 0.000 0.2667 0.093 0.024 0.000 0.000 0.3333 0.093 0.030 0.000 0.000 0.4000 0.093 0.036 0.000 0.000 0.4667 0.093 0.042 0.000 0.000 0.5333 0.093 0.048 0.001 0.000 0.6000 0.093 0.054 0.003 0.000 0.6667 0.093 0.060 0.004 0.000 0.7333 0.093 0.066 0.004 0.000 0.8000 0.093 0.072 0.005 0.000 0.8667 0.093 0.078 0.005 0.000 0.9333 0.093 0.084 0.006 0.000 1.0000 0.093 0.090 0.006 0.000 1.0667 0.093 0.096 0.007 0.000 1.1333 0.093 0.102 0.007 0.000 1.2000 0.093 0.108 0.008 0.000 1.2667 0.093 0.114 0.008 0.000 1.3333 0.093 0.120 0.008 0.000 1.4000 0.093 0.126 0.009 0.000 1.4667 0.093 0.132 0.009 0.000 1.5333 0.093 0.138 0.009 0.000 1.6000 0.093 0.144 0.010 0.000 1.6667 0.093 0.150 0.010 0.000 1.7333 0.093 0.156 0.010 0.000 1.8000 0.093 0.162 0.011 0.000 1.8667 0.093 0.168 0.011 0.000 1.9333 0.093 0.174 0.011 0.000 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 7 2.0000 0.093 0.180 0.012 0.000 2.0667 0.093 0.186 0.012 0.000 2.1333 0.093 0.192 0.012 0.000 2.2000 0.093 0.198 0.012 0.000 2.2667 0.093 0.204 0.013 0.000 2.3333 0.093 0.210 0.013 0.000 2.4000 0.093 0.216 0.013 0.000 2.4667 0.093 0.222 0.013 0.000 2.5333 0.093 0.228 0.013 0.000 2.6000 0.093 0.234 0.014 0.000 2.6667 0.093 0.240 0.014 0.000 2.7333 0.093 0.246 0.014 0.000 2.8000 0.093 0.252 0.014 0.000 2.8667 0.093 0.258 0.015 0.000 2.9333 0.093 0.264 0.015 0.000 3.0000 0.093 0.270 0.015 0.000 3.0667 0.093 0.276 0.015 0.000 3.1333 0.093 0.282 0.017 0.000 3.2000 0.093 0.288 0.019 0.000 3.2667 0.093 0.294 0.020 0.000 3.3333 0.093 0.300 0.021 0.000 3.4000 0.093 0.306 0.022 0.000 3.4667 0.093 0.312 0.022 0.000 3.5333 0.093 0.318 0.023 0.000 3.6000 0.093 0.324 0.024 0.000 3.6667 0.093 0.330 0.024 0.000 3.7333 0.093 0.336 0.025 0.000 3.8000 0.093 0.342 0.025 0.000 3.8667 0.093 0.348 0.026 0.000 3.9333 0.093 0.354 0.027 0.000 4.0000 0.093 0.360 0.027 0.000 4.0667 0.093 0.366 0.028 0.000 4.1333 0.093 0.372 0.028 0.000 4.2000 0.093 0.378 0.029 0.000 4.2667 0.093 0.384 0.029 0.000 4.3333 0.093 0.390 0.030 0.000 4.4000 0.093 0.396 0.030 0.000 4.4667 0.093 0.402 0.030 0.000 4.5333 0.093 0.408 0.031 0.000 4.6000 0.093 0.414 0.031 0.000 4.6667 0.093 0.420 0.032 0.000 4.7333 0.093 0.426 0.032 0.000 4.8000 0.093 0.432 0.033 0.000 4.8667 0.093 0.438 0.033 0.000 4.9333 0.093 0.444 0.033 0.000 5.0000 0.093 0.450 0.034 0.000 5.0667 0.093 0.456 0.034 0.000 5.1333 0.093 0.463 0.035 0.000 5.2000 0.093 0.469 0.035 0.000 5.2667 0.093 0.475 0.042 0.000 5.3333 0.093 0.481 0.046 0.000 5.4000 0.093 0.487 0.048 0.000 5.4667 0.093 0.493 0.050 0.000 5.5333 0.093 0.499 0.052 0.000 5.6000 0.093 0.505 0.054 0.000 5.6667 0.093 0.511 0.056 0.000 5.7333 0.093 0.517 0.058 0.000 5.8000 0.093 0.523 0.059 0.000 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 8 5.8667 0.093 0.529 0.061 0.000 5.9333 0.093 0.535 0.062 0.000 6.0000 0.093 0.541 0.419 0.000 20231218 RoadDetentionModules 12/18/2023 7:55:36 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 1.048 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.145 Total Impervious Area: 0.903 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.030812 5 year 0.048392 10 year 0.058354 25 year 0.068909 50 year 0.07544 100 year 0.080995 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.018737 5 year 0.025895 10 year 0.030996 25 year 0.037859 50 year 0.043279 100 year 0.048966 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.030 0.014 1950 0.038 0.021 1951 0.068 0.033 1952 0.021 0.012 1953 0.017 0.018 1954 0.027 0.015 1955 0.042 0.014 1956 0.034 0.026 1957 0.027 0.015 1958 0.031 0.017 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 10 1959 0.026 0.014 1960 0.046 0.030 1961 0.026 0.023 1962 0.016 0.013 1963 0.022 0.016 1964 0.029 0.022 1965 0.021 0.025 1966 0.020 0.015 1967 0.042 0.021 1968 0.026 0.015 1969 0.026 0.015 1970 0.021 0.016 1971 0.023 0.016 1972 0.051 0.030 1973 0.023 0.025 1974 0.025 0.015 1975 0.034 0.014 1976 0.024 0.015 1977 0.003 0.012 1978 0.021 0.020 1979 0.013 0.012 1980 0.048 0.032 1981 0.019 0.015 1982 0.037 0.028 1983 0.033 0.015 1984 0.020 0.013 1985 0.012 0.013 1986 0.053 0.022 1987 0.047 0.029 1988 0.019 0.014 1989 0.012 0.013 1990 0.099 0.030 1991 0.059 0.030 1992 0.023 0.019 1993 0.024 0.013 1994 0.008 0.011 1995 0.034 0.023 1996 0.072 0.033 1997 0.060 0.034 1998 0.014 0.013 1999 0.057 0.031 2000 0.024 0.021 2001 0.004 0.010 2002 0.026 0.024 2003 0.033 0.015 2004 0.043 0.033 2005 0.031 0.015 2006 0.036 0.026 2007 0.073 0.049 2008 0.095 0.032 2009 0.046 0.025 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0988 0.0495 2 0.0946 0.0344 3 0.0733 0.0334 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 11 4 0.0722 0.0332 5 0.0679 0.0325 6 0.0604 0.0318 7 0.0595 0.0317 8 0.0566 0.0311 9 0.0534 0.0301 10 0.0505 0.0300 11 0.0479 0.0298 12 0.0472 0.0298 13 0.0464 0.0289 14 0.0459 0.0275 15 0.0431 0.0265 16 0.0423 0.0263 17 0.0419 0.0253 18 0.0377 0.0250 19 0.0368 0.0245 20 0.0365 0.0237 21 0.0343 0.0234 22 0.0338 0.0232 23 0.0337 0.0222 24 0.0333 0.0221 25 0.0330 0.0210 26 0.0309 0.0209 27 0.0306 0.0206 28 0.0303 0.0201 29 0.0291 0.0195 30 0.0272 0.0181 31 0.0266 0.0170 32 0.0263 0.0161 33 0.0261 0.0156 34 0.0261 0.0155 35 0.0259 0.0152 36 0.0256 0.0152 37 0.0249 0.0152 38 0.0244 0.0150 39 0.0239 0.0150 40 0.0238 0.0150 41 0.0230 0.0147 42 0.0229 0.0147 43 0.0225 0.0147 44 0.0221 0.0146 45 0.0214 0.0146 46 0.0214 0.0144 47 0.0211 0.0143 48 0.0208 0.0141 49 0.0204 0.0139 50 0.0200 0.0137 51 0.0191 0.0134 52 0.0186 0.0133 53 0.0173 0.0127 54 0.0161 0.0126 55 0.0137 0.0125 56 0.0129 0.0125 57 0.0122 0.0123 58 0.0121 0.0118 59 0.0080 0.0116 60 0.0043 0.0112 61 0.0029 0.0102 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 12 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 13 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0154 17569 17096 97 Pass 0.0160 16164 14014 86 Pass 0.0166 14981 13327 88 Pass 0.0172 13856 12705 91 Pass 0.0178 12814 12136 94 Pass 0.0184 11815 11486 97 Pass 0.0190 10902 10853 99 Pass 0.0197 10119 10121 100 Pass 0.0203 9392 9482 100 Pass 0.0209 8733 8789 100 Pass 0.0215 8143 8115 99 Pass 0.0221 7599 7415 97 Pass 0.0227 7060 6710 95 Pass 0.0233 6592 6068 92 Pass 0.0239 6149 5456 88 Pass 0.0245 5777 4838 83 Pass 0.0251 5435 4391 80 Pass 0.0257 5101 3989 78 Pass 0.0263 4808 3623 75 Pass 0.0269 4528 3311 73 Pass 0.0275 4254 2862 67 Pass 0.0281 4017 2569 63 Pass 0.0287 3784 2301 60 Pass 0.0294 3546 1988 56 Pass 0.0300 3339 1584 47 Pass 0.0306 3138 1206 38 Pass 0.0312 2952 914 30 Pass 0.0318 2787 639 22 Pass 0.0324 2599 488 18 Pass 0.0330 2447 343 14 Pass 0.0336 2308 216 9 Pass 0.0342 2162 164 7 Pass 0.0348 2024 130 6 Pass 0.0354 1900 115 6 Pass 0.0360 1790 114 6 Pass 0.0366 1687 112 6 Pass 0.0372 1586 111 6 Pass 0.0378 1483 110 7 Pass 0.0384 1381 109 7 Pass 0.0391 1292 109 8 Pass 0.0397 1218 107 8 Pass 0.0403 1155 106 9 Pass 0.0409 1098 105 9 Pass 0.0415 1048 104 9 Pass 0.0421 997 104 10 Pass 0.0427 930 103 11 Pass 0.0433 883 100 11 Pass 0.0439 837 98 11 Pass 0.0445 789 78 9 Pass 0.0451 743 56 7 Pass 0.0457 713 52 7 Pass 0.0463 668 47 7 Pass 0.0469 631 41 6 Pass 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 14 0.0475 596 35 5 Pass 0.0482 565 30 5 Pass 0.0488 539 25 4 Pass 0.0494 496 4 0 Pass 0.0500 473 0 0 Pass 0.0506 434 0 0 Pass 0.0512 399 0 0 Pass 0.0518 366 0 0 Pass 0.0524 348 0 0 Pass 0.0530 323 0 0 Pass 0.0536 296 0 0 Pass 0.0542 272 0 0 Pass 0.0548 256 0 0 Pass 0.0554 235 0 0 Pass 0.0560 217 0 0 Pass 0.0566 195 0 0 Pass 0.0572 180 0 0 Pass 0.0579 158 0 0 Pass 0.0585 145 0 0 Pass 0.0591 129 0 0 Pass 0.0597 119 0 0 Pass 0.0603 109 0 0 Pass 0.0609 97 0 0 Pass 0.0615 91 0 0 Pass 0.0621 82 0 0 Pass 0.0627 76 0 0 Pass 0.0633 68 0 0 Pass 0.0639 61 0 0 Pass 0.0645 54 0 0 Pass 0.0651 48 0 0 Pass 0.0657 41 0 0 Pass 0.0663 38 0 0 Pass 0.0670 33 0 0 Pass 0.0676 27 0 0 Pass 0.0682 22 0 0 Pass 0.0688 21 0 0 Pass 0.0694 20 0 0 Pass 0.0700 19 0 0 Pass 0.0706 17 0 0 Pass 0.0712 13 0 0 Pass 0.0718 12 0 0 Pass 0.0724 900Pass 0.0730 400Pass 0.0736 300Pass 0.0742 300Pass 0.0748 300Pass 0.0754 300Pass 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 15 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. 20231218 RoadDetentionModules 12/18/2023 7:56:06 PM Page 16 LID Report 20231218 RoadDetentionModules 12/18/2023 7:56:26 PM Page 17 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20231218 RoadDetentionModules 12/18/2023 7:56:26 PM Page 18 Appendix Predeveloped Schematic 20231218 RoadDetentionModules 12/18/2023 7:56:28 PM Page 19 Mitigated Schematic 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 20 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231218 RoadDetentionModules.wdm MESSU 25 Pre20231218 RoadDetentionModules.MES 27 Pre20231218 RoadDetentionModules.L61 28 Pre20231218 RoadDetentionModules.L62 30 POC20231218 RoadDetentionModules1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Road Detain MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 21 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 22 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Road Detain*** PERLND 10 1.048 COPY 501 12 PERLND 10 1.048 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 23 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 24 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231218 RoadDetentionModules.wdm MESSU 25 Mit20231218 RoadDetentionModules.MES 27 Mit20231218 RoadDetentionModules.L61 28 Mit20231218 RoadDetentionModules.L62 30 POC20231218 RoadDetentionModules1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 8 RCHRES 1 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Gravel Trench Bed 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 25 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 8 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 26 1 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Road Detain*** PERLND 16 0.145 RCHRES 1 2 PERLND 16 0.145 RCHRES 1 3 IMPLND 1 0.687 RCHRES 1 5 IMPLND 8 0.216 RCHRES 1 5 ******Routing****** PERLND 16 0.145 COPY 1 12 IMPLND 1 0.687 COPY 1 15 IMPLND 8 0.216 COPY 1 15 PERLND 16 0.145 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Gravel Trench Be-020 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 27 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.03 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.092975 0.000000 0.000000 0.066667 0.092975 0.006012 0.000000 0.133333 0.092975 0.012025 0.000000 0.200000 0.092975 0.018037 0.000000 0.266667 0.092975 0.024050 0.000000 0.333333 0.092975 0.030062 0.000000 0.400000 0.092975 0.036074 0.000000 0.466667 0.092975 0.042087 0.000000 0.533333 0.092975 0.048099 0.001784 0.600000 0.092975 0.054112 0.003089 0.666667 0.092975 0.060124 0.003988 0.733333 0.092975 0.066136 0.004719 0.800000 0.092975 0.072149 0.005351 0.866667 0.092975 0.078161 0.005916 0.933333 0.092975 0.084174 0.006431 1.000000 0.092975 0.090186 0.006908 1.066667 0.092975 0.096198 0.007354 1.133333 0.092975 0.102211 0.007775 1.200000 0.092975 0.108223 0.008174 1.266667 0.092975 0.114236 0.008554 1.333333 0.092975 0.120248 0.008918 1.400000 0.092975 0.126260 0.009268 1.466667 0.092975 0.132273 0.009605 1.533333 0.092975 0.138285 0.009931 1.600000 0.092975 0.144298 0.010246 1.666667 0.092975 0.150310 0.010552 1.733333 0.092975 0.156322 0.010849 1.800000 0.092975 0.162335 0.011139 1.866667 0.092975 0.168347 0.011421 1.933333 0.092975 0.174360 0.011696 2.000000 0.092975 0.180372 0.011965 2.066667 0.092975 0.186384 0.012228 2.133333 0.092975 0.192397 0.012485 2.200000 0.092975 0.198409 0.012738 2.266667 0.092975 0.204421 0.012985 2.333333 0.092975 0.210434 0.013228 2.400000 0.092975 0.216446 0.013466 2.466667 0.092975 0.222459 0.013700 2.533333 0.092975 0.228471 0.013930 2.600000 0.092975 0.234483 0.014157 2.666667 0.092975 0.240496 0.014380 2.733333 0.092975 0.246508 0.014600 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 28 2.800000 0.092975 0.252521 0.014816 2.866667 0.092975 0.258533 0.015029 2.933333 0.092975 0.264545 0.015239 3.000000 0.092975 0.270558 0.015447 3.066667 0.092975 0.276570 0.015651 3.133333 0.092975 0.282583 0.017637 3.200000 0.092975 0.288595 0.019142 3.266667 0.092975 0.294607 0.020238 3.333333 0.092975 0.300620 0.021163 3.400000 0.092975 0.306632 0.021987 3.466667 0.092975 0.312645 0.022742 3.533333 0.092975 0.318657 0.023445 3.600000 0.092975 0.324669 0.024108 3.666667 0.092975 0.330682 0.024739 3.733333 0.092975 0.336694 0.025341 3.800000 0.092975 0.342707 0.025920 3.866667 0.092975 0.348719 0.026479 3.933333 0.092975 0.354731 0.027020 4.000000 0.092975 0.360744 0.027545 4.066667 0.092975 0.366756 0.028055 4.133333 0.092975 0.372769 0.028552 4.200000 0.092975 0.378781 0.029038 4.266667 0.092975 0.384793 0.029512 4.333333 0.092975 0.390806 0.029976 4.400000 0.092975 0.396818 0.030431 4.466667 0.092975 0.402831 0.030878 4.533333 0.092975 0.408843 0.031316 4.600000 0.092975 0.414855 0.031746 4.666667 0.092975 0.420868 0.032169 4.733333 0.092975 0.426880 0.032586 4.800000 0.092975 0.432893 0.032995 4.866667 0.092975 0.438905 0.033399 4.933333 0.092975 0.444917 0.033797 5.000000 0.092975 0.450930 0.034190 5.066667 0.092975 0.456942 0.034577 5.133333 0.092975 0.462955 0.034959 5.200000 0.092975 0.468967 0.035336 5.266667 0.092975 0.474979 0.042716 5.333333 0.092975 0.480992 0.045986 5.400000 0.092975 0.487004 0.048577 5.466667 0.092975 0.493017 0.050814 5.533333 0.092975 0.499029 0.052824 5.600000 0.092975 0.505041 0.054671 5.666667 0.092975 0.511054 0.056395 5.733333 0.092975 0.517066 0.058020 5.800000 0.092975 0.523079 0.059563 5.866667 0.092975 0.529091 0.061038 5.933333 0.092975 0.535103 0.062454 6.000000 0.092975 0.541116 0.419764 6.066667 0.092975 0.547314 1.332663 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 RCHRES 1 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1008 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1009 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 29 COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 30 Predeveloped HSPF Message File 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 31 Mitigated HSPF Message File 20231218 RoadDetentionModules 12/18/2023 7:56:29 PM Page 32 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 2 General Model Information WWHM2012 Project Name: 20231219 NorthTreatment Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/19/2023 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2023/03/31 Version: 4.2.19 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year Low Flow Threshold for POC2: 50 Percent of the 2 Year High Flow Threshold for POC2: 50 Year 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 3 Landuse Basin Data Predeveloped Land Use North Half 3A Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 3.353 Pervious Total 3.353 Impervious Land Use acre Impervious Total 0 Basin Total 3.353 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 4 North Half 3B Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 1.021 Pervious Total 1.021 Impervious Land Use acre Impervious Total 0 Basin Total 1.021 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 5 Mitigated Land Use Basin 3A Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.65 Pervious Total 0.65 Impervious Land Use acre ROADS FLAT 2.703 Impervious Total 2.703 Basin Total 3.353 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 6 Treatment Basin 3B Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.041 Pervious Total 0.041 Impervious Land Use acre ROADS FLAT 0.98 Impervious Total 0.98 Basin Total 1.021 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 7 Routing Elements Predeveloped Routing 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 8 Mitigated Routing Bioretention 3B Bottom Length: 31.00 ft. Bottom Width: 10.00 ft. Material thickness of first layer: 0.25 Material type for first layer: ASTM 100 Material thickness of second layer: 1.5 Material type for second layer: SMMWW 12 in/hr Material thickness of third layer: 1 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet): 0.5 Orifice Diameter (in.): 6 Offset (in.): 0 Flow Through Underdrain (ac-ft.): 146.184 Total Outflow (ac-ft.): 160.208 Percent Through Underdrain: 91.25 Discharge Structure Riser Height: 1 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Bioretention Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0289 0.0000 0.0000 0.0000 0.0467 0.0285 0.0002 0.0000 0.0000 0.0934 0.0280 0.0003 0.0000 0.0000 0.1401 0.0275 0.0005 0.0000 0.0000 0.1868 0.0271 0.0007 0.0000 0.0000 0.2335 0.0266 0.0009 0.0000 0.0000 0.2802 0.0262 0.0011 0.0001 0.0000 0.3269 0.0257 0.0013 0.0002 0.0000 0.3736 0.0253 0.0015 0.0003 0.0000 0.4203 0.0248 0.0017 0.0004 0.0000 0.4670 0.0244 0.0019 0.0006 0.0000 0.5137 0.0239 0.0021 0.0008 0.0000 0.5604 0.0235 0.0023 0.0008 0.0000 0.6071 0.0231 0.0026 0.0010 0.0000 0.6538 0.0226 0.0028 0.0013 0.0000 0.7005 0.0222 0.0030 0.0016 0.0000 0.7473 0.0218 0.0033 0.0020 0.0000 0.7940 0.0214 0.0035 0.0024 0.0000 0.8407 0.0210 0.0038 0.0029 0.0000 0.8874 0.0206 0.0041 0.0034 0.0000 0.9341 0.0201 0.0044 0.0034 0.0000 0.9808 0.0197 0.0046 0.0040 0.0000 1.0275 0.0193 0.0049 0.0046 0.0000 1.0742 0.0189 0.0052 0.0053 0.0000 1.1209 0.0186 0.0055 0.0060 0.0000 1.1676 0.0182 0.0058 0.0068 0.0000 1.2143 0.0178 0.0062 0.0077 0.0000 1.2610 0.0174 0.0065 0.0084 0.0000 1.3077 0.0170 0.0068 0.0086 0.0000 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 9 1.3544 0.0167 0.0072 0.0096 0.0000 1.4011 0.0163 0.0075 0.0106 0.0000 1.4478 0.0159 0.0079 0.0118 0.0000 1.4945 0.0156 0.0083 0.0129 0.0000 1.5412 0.0152 0.0086 0.0142 0.0000 1.5879 0.0148 0.0090 0.0155 0.0000 1.6346 0.0145 0.0094 0.0162 0.0000 1.6813 0.0141 0.0098 0.0169 0.0000 1.7280 0.0138 0.0102 0.0183 0.0000 1.7747 0.0135 0.0106 0.0199 0.0000 1.8214 0.0131 0.0110 0.0214 0.0000 1.8681 0.0128 0.0114 0.0215 0.0000 1.9148 0.0124 0.0118 0.0215 0.0000 1.9615 0.0121 0.0122 0.0215 0.0000 2.0082 0.0118 0.0126 0.0215 0.0000 2.0549 0.0115 0.0130 0.0215 0.0000 2.1016 0.0112 0.0135 0.0215 0.0000 2.1484 0.0109 0.0139 0.0215 0.0000 2.1951 0.0105 0.0144 0.0215 0.0000 2.2418 0.0102 0.0148 0.0215 0.0000 2.2885 0.0099 0.0153 0.0395 0.0000 2.3352 0.0096 0.0158 0.0395 0.0000 2.3819 0.0093 0.0163 0.0395 0.0000 2.4286 0.0091 0.0167 0.0395 0.0000 2.4753 0.0088 0.0172 0.0395 0.0000 2.5220 0.0085 0.0178 0.0395 0.0000 2.5687 0.0082 0.0183 0.0395 0.0000 2.6154 0.0079 0.0188 0.0395 0.0000 2.6621 0.0077 0.0193 0.0395 0.0000 2.7088 0.0074 0.0199 0.0395 0.0000 2.7500 0.0071 0.0204 0.0395 0.0000 Bioretention Surface Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)To Amended(cfs)Infilt(cfs) 2.7500 0.0289 0.0204 0.0000 0.0258 0.0000 2.7967 0.0294 0.0217 0.0000 0.0258 0.0000 2.8434 0.0299 0.0231 0.0000 0.0265 0.0000 2.8901 0.0303 0.0245 0.0000 0.0271 0.0000 2.9368 0.0308 0.0260 0.0000 0.0278 0.0000 2.9835 0.0313 0.0274 0.0000 0.0285 0.0000 3.0302 0.0318 0.0289 0.0000 0.0291 0.0000 3.0769 0.0323 0.0304 0.0000 0.0298 0.0000 3.1236 0.0328 0.0319 0.0000 0.0305 0.0000 3.1703 0.0333 0.0335 0.0000 0.0311 0.0000 3.2170 0.0338 0.0350 0.0000 0.0318 0.0000 3.2637 0.0344 0.0366 0.0000 0.0325 0.0000 3.3104 0.0349 0.0382 0.0000 0.0332 0.0000 3.3571 0.0354 0.0399 0.0000 0.0338 0.0000 3.4038 0.0359 0.0415 0.0000 0.0345 0.0000 3.4505 0.0364 0.0432 0.0000 0.0352 0.0000 3.4973 0.0370 0.0449 0.0000 0.0358 0.0000 3.5440 0.0375 0.0467 0.0000 0.0365 0.0000 3.5907 0.0380 0.0484 0.0000 0.0372 0.0000 3.6374 0.0386 0.0502 0.0000 0.0379 0.0000 3.6841 0.0391 0.0520 0.0000 0.0385 0.0000 3.7308 0.0397 0.0539 0.0000 0.0392 0.0000 3.7775 0.0402 0.0558 0.0483 0.0395 0.0000 3.8242 0.0408 0.0576 0.2137 0.0395 0.0000 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 10 3.8709 0.0414 0.0596 0.4414 0.0395 0.0000 3.9176 0.0419 0.0615 0.7089 0.0395 0.0000 3.9643 0.0425 0.0635 0.9966 0.0395 0.0000 4.0110 0.0431 0.0655 1.2841 0.0395 0.0000 4.0577 0.0436 0.0675 1.5516 0.0395 0.0000 4.1044 0.0442 0.0696 1.7818 0.0395 0.0000 4.1511 0.0448 0.0716 1.9637 0.0395 0.0000 4.1978 0.0454 0.0737 2.0963 0.0395 0.0000 4.2445 0.0460 0.0759 2.1930 0.0395 0.0000 4.2500 0.0460 0.0761 2.3171 0.0395 0.0000 20231219 NorthTreatment 12/19/2023 1:20:02 PM Page 11 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 3.353 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.65 Total Impervious Area: 2.703 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.098581 5 year 0.154825 10 year 0.1867 25 year 0.220468 50 year 0.241364 100 year 0.259137 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.072069 5 year 1.369007 10 year 1.572458 25 year 1.838109 50 year 2.042612 100 year 2.253034 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.097 1.429 1950 0.121 1.457 1951 0.217 0.891 1952 0.068 0.749 1953 0.055 0.809 1954 0.085 0.873 1955 0.135 0.980 1956 0.108 0.967 1957 0.087 1.123 1958 0.098 0.879 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 12 1959 0.084 0.873 1960 0.147 0.920 1961 0.083 0.952 1962 0.052 0.803 1963 0.071 0.921 1964 0.093 0.868 1965 0.067 1.163 1966 0.064 0.754 1967 0.134 1.307 1968 0.084 1.488 1969 0.082 1.058 1970 0.067 1.001 1971 0.072 1.194 1972 0.162 1.286 1973 0.073 0.716 1974 0.080 1.103 1975 0.108 1.204 1976 0.078 0.853 1977 0.009 0.878 1978 0.069 1.078 1979 0.041 1.479 1980 0.153 1.447 1981 0.061 1.114 1982 0.118 1.600 1983 0.106 1.259 1984 0.065 0.810 1985 0.039 1.115 1986 0.171 0.949 1987 0.151 1.458 1988 0.060 0.872 1989 0.039 1.090 1990 0.316 2.081 1991 0.190 1.620 1992 0.073 0.803 1993 0.076 0.683 1994 0.026 0.728 1995 0.110 0.984 1996 0.231 1.095 1997 0.193 1.050 1998 0.044 1.021 1999 0.181 2.176 2000 0.076 1.066 2001 0.014 1.132 2002 0.084 1.403 2003 0.107 1.091 2004 0.138 2.026 2005 0.099 0.928 2006 0.117 0.829 2007 0.235 1.904 2008 0.303 1.591 2009 0.149 1.334 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.3160 2.1758 2 0.3026 2.0808 3 0.2346 2.0259 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 13 4 0.2310 1.9035 5 0.2171 1.6197 6 0.1931 1.5997 7 0.1903 1.5907 8 0.1811 1.4878 9 0.1709 1.4794 10 0.1617 1.4577 11 0.1532 1.4574 12 0.1511 1.4466 13 0.1486 1.4291 14 0.1468 1.4034 15 0.1380 1.3338 16 0.1355 1.3068 17 0.1340 1.2861 18 0.1207 1.2594 19 0.1178 1.2040 20 0.1167 1.1939 21 0.1096 1.1633 22 0.1080 1.1317 23 0.1078 1.1228 24 0.1066 1.1150 25 0.1056 1.1144 26 0.0990 1.1025 27 0.0980 1.0946 28 0.0968 1.0906 29 0.0931 1.0903 30 0.0870 1.0776 31 0.0850 1.0661 32 0.0841 1.0580 33 0.0836 1.0499 34 0.0835 1.0214 35 0.0828 1.0005 36 0.0818 0.9842 37 0.0797 0.9800 38 0.0781 0.9670 39 0.0764 0.9515 40 0.0762 0.9486 41 0.0734 0.9284 42 0.0734 0.9212 43 0.0721 0.9197 44 0.0707 0.8907 45 0.0685 0.8789 46 0.0684 0.8776 47 0.0675 0.8734 48 0.0667 0.8731 49 0.0652 0.8719 50 0.0641 0.8683 51 0.0612 0.8532 52 0.0596 0.8289 53 0.0553 0.8102 54 0.0515 0.8091 55 0.0437 0.8033 56 0.0414 0.8026 57 0.0389 0.7536 58 0.0387 0.7489 59 0.0257 0.7276 60 0.0137 0.7161 61 0.0093 0.6829 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 14 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 15 Duration Flows The Facility PASSED Flow(cfs) Predev Mit Percentage Pass/Fail 0.0493 0 1717 n/a Fail 0.0512 0 1574 n/a Fail 0.0532 0 1425 n/a Fail 0.0551 0 1278 n/a Fail 0.0571 0 1152 n/a Fail 0.0590 0 1048 n/a Fail 0.0609 0 961 n/a Fail 0.0629 0 884 n/a Fail 0.0648 0 813 n/a Fail 0.0668 0 744 n/a Fail 0.0687 0 677 n/a Fail 0.0706 0 628 n/a Fail 0.0726 0 577 n/a Fail 0.0745 0 540 n/a Fail 0.0765 0 503 n/a Fail 0.0784 0 459 n/a Fail 0.0803 0 422 n/a Fail 0.0823 0 393 n/a Fail 0.0842 0 369 n/a Fail 0.0862 0 352 n/a Fail 0.0881 0 322 n/a Fail 0.0900 0 303 n/a Fail 0.0920 0 277 n/a Fail 0.0939 0 260 n/a Fail 0.0959 0 240 n/a Fail 0.0978 0 225 n/a Fail 0.0997 0 209 n/a Fail 0.1017 0 199 n/a Fail 0.1036 0 183 n/a Fail 0.1056 0 172 n/a Fail 0.1075 0 162 n/a Fail 0.1094 0 149 n/a Fail 0.1114 0 143 n/a Fail 0.1133 0 132 n/a Fail 0.1153 0 123 n/a Fail 0.1172 0 116 n/a Fail 0.1191 0 112 n/a Fail 0.1211 0 102 n/a Fail 0.1230 0 100 n/a Fail 0.1250 0 90 n/a Fail 0.1269 0 82 n/a Fail 0.1288 0 82 n/a Fail 0.1308 0 79 n/a Fail 0.1327 0 78 n/a Fail 0.1347 0 73 n/a Fail 0.1366 0 69 n/a Fail 0.1385 0 64 n/a Fail 0.1405 0 62 n/a Fail 0.1424 0 58 n/a Fail 0.1444 0 56 n/a Fail 0.1463 0 51 n/a Fail 0.1482 0 49 n/a Fail 0.1502 0 48 n/a Fail 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 16 0.1521 0 45 n/a Fail 0.1541 0 41 n/a Fail 0.1560 0 40 n/a Fail 0.1579 0 37 n/a Fail 0.1599 0 35 n/a Fail 0.1618 0 31 n/a Fail 0.1638 0 30 n/a Fail 0.1657 0 27 n/a Fail 0.1676 0 23 n/a Fail 0.1696 0 23 n/a Fail 0.1715 0 20 n/a Fail 0.1735 0 17 n/a Fail 0.1754 0 16 n/a Fail 0.1773 0 16 n/a Fail 0.1793 0 15 n/a Fail 0.1812 0 13 n/a Fail 0.1832 0 12 n/a Fail 0.1851 0 10 n/a Fail 0.1870 0 9 n/a Fail 0.1890 0 8 n/a Fail 0.1909 0 8 n/a Fail 0.1929 0 8 n/a Fail 0.1948 0 8 n/a Fail 0.1967 0 8 n/a Fail 0.1987 0 8 n/a Fail 0.2006 0 8 n/a Fail 0.2026 0 8 n/a Fail 0.2045 0 8 n/a Fail 0.2064 0 8 n/a Fail 0.2084 0 8 n/a Fail 0.2103 0 7 n/a Fail 0.2123 0 7 n/a Fail 0.2142 0 7 n/a Fail 0.2161 0 7 n/a Fail 0.2181 0 6 n/a Fail 0.2200 0 6 n/a Fail 0.2220 0 6 n/a Fail 0.2239 0 5 n/a Fail 0.2258 0 5 n/a Fail 0.2278 0 4 n/a Fail 0.2297 0 4 n/a Fail 0.2317 0 4 n/a Fail 0.2336 0 4 n/a Fail 0.2355 0 3 n/a Fail 0.2375 0 3 n/a Fail 0.2394 0 2 n/a Fail 0.2414 0 2 n/a Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 17 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0.3526 acre-feet On-line facility target flow: 0.4345 cfs. Adjusted for 15 min: 0.4345 cfs. Off-line facility target flow: 0.2446 cfs. Adjusted for 15 min: 0.2446 cfs. 20231219 NorthTreatment 12/19/2023 1:20:26 PM Page 18 LID Report 20231219 NorthTreatment 12/19/2023 1:20:58 PM Page 19 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area: 1.021 Total Impervious Area: 0 Mitigated Landuse Totals for POC #2 Total Pervious Area: 0.041 Total Impervious Area: 0.98 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.030018 5 year 0.047145 10 year 0.056851 25 year 0.067133 50 year 0.073496 100 year 0.078908 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.291627 5 year 0.412983 10 year 0.489511 25 year 0.581686 50 year 0.647203 100 year 0.710199 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.029 0.255 1950 0.037 0.446 1951 0.066 0.296 1952 0.021 0.222 1953 0.017 0.200 1954 0.026 0.210 1955 0.041 0.286 1956 0.033 0.251 1957 0.026 0.379 1958 0.030 0.197 1959 0.026 0.215 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 20 1960 0.045 0.294 1961 0.025 0.310 1962 0.016 0.152 1963 0.022 0.189 1964 0.028 0.197 1965 0.020 0.198 1966 0.020 0.258 1967 0.041 0.432 1968 0.025 0.372 1969 0.025 0.331 1970 0.021 0.322 1971 0.022 0.306 1972 0.049 0.376 1973 0.022 0.183 1974 0.024 0.237 1975 0.033 0.364 1976 0.024 0.272 1977 0.003 0.131 1978 0.021 0.360 1979 0.013 0.167 1980 0.047 0.451 1981 0.019 0.380 1982 0.036 0.530 1983 0.032 0.407 1984 0.020 0.177 1985 0.012 0.373 1986 0.052 0.301 1987 0.046 0.345 1988 0.018 0.191 1989 0.012 0.093 1990 0.096 0.642 1991 0.058 0.533 1992 0.022 0.236 1993 0.023 0.185 1994 0.008 0.087 1995 0.033 0.259 1996 0.070 0.349 1997 0.059 0.274 1998 0.013 0.245 1999 0.055 0.562 2000 0.023 0.292 2001 0.004 0.339 2002 0.025 0.462 2003 0.032 0.180 2004 0.042 0.678 2005 0.030 0.304 2006 0.036 0.244 2007 0.071 0.591 2008 0.092 0.535 2009 0.045 0.362 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0962 0.6777 2 0.0921 0.6423 3 0.0714 0.5912 4 0.0703 0.5625 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 21 5 0.0661 0.5354 6 0.0588 0.5327 7 0.0579 0.5302 8 0.0551 0.4625 9 0.0520 0.4509 10 0.0492 0.4461 11 0.0467 0.4321 12 0.0460 0.4073 13 0.0452 0.3797 14 0.0447 0.3785 15 0.0420 0.3760 16 0.0413 0.3733 17 0.0408 0.3717 18 0.0368 0.3642 19 0.0359 0.3617 20 0.0355 0.3599 21 0.0334 0.3489 22 0.0329 0.3448 23 0.0328 0.3389 24 0.0324 0.3313 25 0.0321 0.3217 26 0.0301 0.3103 27 0.0298 0.3059 28 0.0295 0.3036 29 0.0284 0.3014 30 0.0265 0.2965 31 0.0259 0.2938 32 0.0256 0.2918 33 0.0255 0.2861 34 0.0254 0.2743 35 0.0252 0.2717 36 0.0249 0.2586 37 0.0243 0.2585 38 0.0238 0.2553 39 0.0233 0.2510 40 0.0232 0.2454 41 0.0224 0.2439 42 0.0223 0.2368 43 0.0220 0.2359 44 0.0215 0.2216 45 0.0209 0.2153 46 0.0208 0.2096 47 0.0205 0.2003 48 0.0203 0.1981 49 0.0198 0.1970 50 0.0195 0.1969 51 0.0186 0.1914 52 0.0182 0.1891 53 0.0168 0.1848 54 0.0157 0.1829 55 0.0133 0.1802 56 0.0126 0.1766 57 0.0118 0.1667 58 0.0118 0.1522 59 0.0078 0.1311 60 0.0042 0.0929 61 0.0028 0.0875 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 22 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 23 Duration Flows The Duration Matching Failed Flow(cfs) Predev Mit Percentage Pass/Fail 0.0150 17579 193932 1103 Fail 0.0156 16185 188820 1166 Fail 0.0162 14964 180800 1208 Fail 0.0168 13851 172479 1245 Fail 0.0174 12814 167859 1309 Fail 0.0180 11813 164073 1388 Fail 0.0186 10900 160416 1471 Fail 0.0191 10121 157122 1552 Fail 0.0197 9388 153828 1638 Fail 0.0203 8735 150427 1722 Fail 0.0209 8153 147219 1805 Fail 0.0215 7602 138172 1817 Fail 0.0221 7069 85897 1215 Fail 0.0227 6592 85491 1296 Fail 0.0233 6151 85042 1382 Fail 0.0239 5777 84593 1464 Fail 0.0245 5431 84122 1548 Fail 0.0251 5097 83609 1640 Fail 0.0256 4808 83031 1726 Fail 0.0262 4526 81384 1798 Fail 0.0268 4254 77470 1821 Fail 0.0274 4017 73428 1827 Fail 0.0280 3784 69492 1836 Fail 0.0286 3548 65578 1848 Fail 0.0292 3339 61749 1849 Fail 0.0298 3138 58092 1851 Fail 0.0304 2954 54349 1839 Fail 0.0310 2785 50649 1818 Fail 0.0316 2597 47162 1816 Fail 0.0321 2447 43719 1786 Fail 0.0327 2304 40446 1755 Fail 0.0333 2160 37217 1723 Fail 0.0339 2026 34137 1684 Fail 0.0345 1898 31292 1648 Fail 0.0351 1790 28511 1592 Fail 0.0357 1688 25774 1526 Fail 0.0363 1587 23207 1462 Fail 0.0369 1483 20679 1394 Fail 0.0375 1381 18255 1321 Fail 0.0380 1293 15911 1230 Fail 0.0386 1217 13539 1112 Fail 0.0392 1154 10724 929 Fail 0.0398 1098 10598 965 Fail 0.0404 1048 10506 1002 Fail 0.0410 997 10431 1046 Fail 0.0416 930 10350 1112 Fail 0.0422 883 10258 1161 Fail 0.0428 837 10177 1215 Fail 0.0434 789 10085 1278 Fail 0.0440 743 9991 1344 Fail 0.0445 713 9912 1390 Fail 0.0451 668 9805 1467 Fail 0.0457 631 9717 1539 Fail 0.0463 595 9616 1616 Fail 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 24 0.0469 565 9550 1690 Fail 0.0475 539 9460 1755 Fail 0.0481 496 9358 1886 Fail 0.0487 473 9274 1960 Fail 0.0493 434 9176 2114 Fail 0.0499 399 9097 2279 Fail 0.0505 366 8998 2458 Fail 0.0510 348 8902 2558 Fail 0.0516 323 8834 2734 Fail 0.0522 296 8748 2955 Fail 0.0528 272 8656 3182 Fail 0.0534 256 8577 3350 Fail 0.0540 235 8479 3608 Fail 0.0546 217 8387 3864 Fail 0.0552 195 8288 4250 Fail 0.0558 180 8209 4560 Fail 0.0564 158 8132 5146 Fail 0.0570 145 8046 5548 Fail 0.0575 129 7972 6179 Fail 0.0581 119 7884 6625 Fail 0.0587 109 7800 7155 Fail 0.0593 97 7702 7940 Fail 0.0599 91 7638 8393 Fail 0.0605 82 7548 9204 Fail 0.0611 76 7475 9835 Fail 0.0617 68 7381 10854 Fail 0.0623 61 7294 11957 Fail 0.0629 54 7225 13379 Fail 0.0635 48 7163 14922 Fail 0.0640 41 7080 17268 Fail 0.0646 38 6998 18415 Fail 0.0652 33 6921 20972 Fail 0.0658 27 6842 25340 Fail 0.0664 22 6774 30790 Fail 0.0670 21 6695 31880 Fail 0.0676 20 6620 33100 Fail 0.0682 19 6543 34436 Fail 0.0688 17 6464 38023 Fail 0.0694 13 6393 49176 Fail 0.0700 12 6320 52666 Fail 0.0705 8 6256 78200 Fail 0.0711 4 6188 154700 Fail 0.0717 3 6117 203900 Fail 0.0723 3 6059 201966 Fail 0.0729 3 5976 199200 Fail 0.0735 3 5923 197433 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 25 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume: 0.1201 acre-feet On-line facility target flow: 0.1553 cfs. Adjusted for 15 min: 0.1553 cfs. Off-line facility target flow: 0.0877 cfs. Adjusted for 15 min: 0.0877 cfs. 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 26 LID Report 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 27 POC 3 POC #3 was not reported because POC must exist in both scenarios and both scenarios must have been run. 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 28 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 20231219 NorthTreatment 12/19/2023 1:21:21 PM Page 29 Appendix Predeveloped Schematic 20231219 NorthTreatment 12/19/2023 1:21:23 PM Page 30 Mitigated Schematic 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 31 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231219 NorthTreatment.wdm MESSU 25 Pre20231219 NorthTreatment.MES 27 Pre20231219 NorthTreatment.L61 28 Pre20231219 NorthTreatment.L62 30 POC20231219 NorthTreatment1.dat 31 POC20231219 NorthTreatment2.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 North Half 3A MAX 1 2 30 9 2 North Half 3B MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 32 <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 33 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** North Half 3A*** PERLND 10 3.353 COPY 501 12 PERLND 10 3.353 COPY 501 13 North Half 3B*** PERLND 10 1.021 COPY 502 12 PERLND 10 1.021 COPY 502 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 34 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 502 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 35 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 20231219 NorthTreatment.wdm MESSU 25 Mit20231219 NorthTreatment.MES 27 Mit20231219 NorthTreatment.L61 28 Mit20231219 NorthTreatment.L62 30 POC20231219 NorthTreatment1.dat 31 POC20231219 NorthTreatment2.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 RCHRES 1 RCHRES 2 COPY 501 COPY 2 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 3A MAX 1 2 30 9 2 Surface retention 3B MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 2 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 36 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 37 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Treatment Basin 3B*** PERLND 16 0.041 RCHRES 1 2 PERLND 16 0.041 RCHRES 1 3 IMPLND 1 0.98 RCHRES 1 5 Basin 3A*** PERLND 16 0.65 COPY 501 12 PERLND 16 0.65 COPY 501 13 IMPLND 1 2.703 COPY 501 15 ******Routing****** RCHRES 1 1 RCHRES 2 8 PERLND 16 0.041 COPY 2 12 IMPLND 1 0.98 COPY 2 15 PERLND 16 0.041 COPY 2 13 RCHRES 2 1 COPY 502 16 RCHRES 1 1 COPY 502 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Surface retentio-021 2 1 1 1 28 0 1 2 Bioretention 3B 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 38 <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.0 0.0 2 2 0.01 0.0 0.0 0.0 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 2 60 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.028897 0.000000 0.000000 0.046703 0.028478 0.000171 0.000000 0.093407 0.028007 0.000348 0.000000 0.140110 0.027540 0.000532 0.000000 0.186813 0.027076 0.000722 0.000000 0.233516 0.026616 0.000919 0.000000 0.280220 0.026159 0.001103 0.000109 0.326923 0.025706 0.001293 0.000185 0.373626 0.025257 0.001490 0.000288 0.420330 0.024811 0.001692 0.000421 0.467033 0.024369 0.001901 0.000588 0.513736 0.023930 0.002117 0.000791 0.560440 0.023495 0.002339 0.000832 0.607143 0.023064 0.002567 0.001032 0.653846 0.022636 0.002802 0.001314 0.700549 0.022212 0.003044 0.001639 0.747253 0.021791 0.003292 0.002010 0.793956 0.021374 0.003548 0.002428 0.840659 0.020961 0.003810 0.002895 0.887363 0.020551 0.004080 0.003413 0.934066 0.020145 0.004356 0.003450 0.980769 0.019742 0.004640 0.003983 1.027473 0.019343 0.004931 0.004609 1.074176 0.018948 0.005229 0.005290 1.120879 0.018556 0.005534 0.006029 1.167582 0.018168 0.005848 0.006827 1.214286 0.017783 0.006168 0.007686 1.260989 0.017403 0.006497 0.008422 1.307692 0.017025 0.006833 0.008607 1.354396 0.016652 0.007176 0.009592 1.401099 0.016281 0.007528 0.010641 1.447802 0.015915 0.007888 0.011756 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 39 1.494505 0.015552 0.008255 0.012938 1.541209 0.015193 0.008631 0.014187 1.587912 0.014837 0.009015 0.015505 1.634615 0.014485 0.009407 0.016217 1.681319 0.014137 0.009808 0.016892 1.728022 0.013792 0.010217 0.018345 1.774725 0.013450 0.010595 0.019861 1.821429 0.013113 0.010982 0.021403 1.868132 0.012779 0.011376 0.021528 1.914835 0.012448 0.011779 0.021528 1.961538 0.012121 0.012189 0.021528 2.008242 0.011798 0.012607 0.021528 2.054945 0.011478 0.013034 0.021528 2.101648 0.011162 0.013468 0.021528 2.148352 0.010850 0.013911 0.021528 2.195055 0.010541 0.014362 0.021528 2.241758 0.010236 0.014822 0.021528 2.288462 0.009934 0.015290 0.039468 2.335165 0.009636 0.015767 0.039468 2.381868 0.009342 0.016252 0.039468 2.428571 0.009051 0.016746 0.039468 2.475275 0.008764 0.017248 0.039468 2.521978 0.008480 0.017760 0.039468 2.568681 0.008200 0.018280 0.039468 2.615385 0.007924 0.018809 0.039468 2.662088 0.007651 0.019348 0.039468 2.708791 0.007382 0.019895 0.039468 2.750000 0.007117 0.021201 0.039468 END FTABLE 2 FTABLE 1 34 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.007117 0.000000 0.000000 0.000000 0.046703 0.029375 0.001361 0.000000 0.025786 0.093407 0.029856 0.002744 0.000000 0.026456 0.140110 0.030341 0.004150 0.000000 0.027127 0.186813 0.030830 0.005578 0.000000 0.027797 0.233516 0.031322 0.007029 0.000000 0.028467 0.280220 0.031818 0.008504 0.000000 0.029137 0.326923 0.032318 0.010001 0.000000 0.029808 0.373626 0.032821 0.011523 0.000000 0.030478 0.420330 0.033327 0.013067 0.000000 0.031148 0.467033 0.033838 0.014636 0.000000 0.031819 0.513736 0.034351 0.016228 0.000000 0.032489 0.560440 0.034869 0.017844 0.000000 0.033159 0.607143 0.035390 0.019485 0.000000 0.033829 0.653846 0.035915 0.021150 0.000000 0.034500 0.700549 0.036443 0.022840 0.000000 0.035170 0.747253 0.036975 0.024554 0.000000 0.035840 0.793956 0.037511 0.026294 0.000000 0.036511 0.840659 0.038050 0.028058 0.000000 0.037181 0.887363 0.038592 0.029848 0.000000 0.037851 0.934066 0.039139 0.031663 0.000000 0.038521 0.980769 0.039689 0.033504 0.000000 0.039192 1.027473 0.040242 0.035370 0.048301 0.039468 1.074176 0.040799 0.037263 0.213745 0.039468 1.120879 0.041360 0.039181 0.441409 0.039468 1.167582 0.041925 0.041126 0.708936 0.039468 1.214286 0.042493 0.043097 0.996598 0.039468 1.260989 0.043064 0.045095 1.284115 0.039468 1.307692 0.043639 0.047120 1.551565 0.039468 1.354396 0.044218 0.049172 1.781797 0.039468 1.401099 0.044800 0.051250 1.963728 0.039468 1.447802 0.045386 0.053356 2.096308 0.039468 1.494505 0.045976 0.055490 2.193018 0.039468 1.500000 0.046046 0.055743 2.317085 0.039468 END FTABLE 1 END FTABLES 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 40 EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 1 EVAP ENGL 0.5 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL RCHRES 2 HYDR RO 1 1 1 WDM 1008 FLOW ENGL REPL RCHRES 2 HYDR STAGE 1 1 1 WDM 1009 STAG ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1010 STAG ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1011 FLOW ENGL REPL COPY 2 OUTPUT MEAN 1 1 48.4 WDM 702 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 802 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 8 RCHRES OFLOW OVOL 2 RCHRES INFLOW IVOL END MASS-LINK 8 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 41 Predeveloped HSPF Message File 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 42 Mitigated HSPF Message File 20231219 NorthTreatment 12/19/2023 1:21:24 PM Page 43 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 2215 North 30th Street Suite 300 Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX WWHM2012 PROJECT REPORT South Bioretention 1 12/22/2023 4:00:47 PM Page 2 General Model Information Project Name: South Bioretention 1 Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/22/2023 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2018/10/10 Version: 4.2.16 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year South Bioretention 1 12/22/2023 4:00:47 PM Page 3 Landuse Basin Data Predeveloped Land Use South Half Bioretention 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 0.112 Pervious Total 0.112 Impervious Land Use acre Impervious Total 0 Basin Total 0.112 Element Flows To: Surface Interflow Groundwater South Bioretention 1 12/22/2023 4:00:47 PM Page 4 Mitigated Land Use South Bioretention 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.112 Impervious Total 0.112 Basin Total 0.112 Element Flows To: Surface Interflow Groundwater Surface retention 1 South Bioretention 1 12/22/2023 4:00:47 PM Page 5 Routing Elements Predeveloped Routing South Bioretention 1 12/22/2023 4:00:47 PM Page 6 Mitigated Routing Bioretention 1 Bottom Length: 7.00 ft. Bottom Width: 5.00 ft. Material thickness of first layer: 0.25 Material type for first layer: ASTM 100 Material thickness of second layer: 1.5 Material type for second layer: SMMWW 12 in/hr Material thickness of third layer: 1.5 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet): 0.5 Orifice Diameter (in.): 1.007 Offset (in.): 0 Flow Through Underdrain (ac-ft.): 17.73 Total Outflow (ac-ft.): 19.154 Percent Through Underdrain: 92.57 Discharge Structure Riser Height: 0.5 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Bioretention Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0149 0.0000 0.0000 0.0000 0.0467 0.0147 0.0000 0.0000 0.0000 0.0934 0.0144 0.0000 0.0000 0.0000 0.1401 0.0141 0.0001 0.0000 0.0000 0.1868 0.0138 0.0001 0.0000 0.0000 0.2335 0.0134 0.0001 0.0000 0.0000 0.2802 0.0131 0.0001 0.0000 0.0000 0.3269 0.0128 0.0002 0.0000 0.0000 0.3736 0.0125 0.0002 0.0000 0.0000 0.4203 0.0122 0.0002 0.0000 0.0000 0.4670 0.0119 0.0003 0.0001 0.0000 0.5137 0.0116 0.0003 0.0001 0.0000 0.5604 0.0113 0.0004 0.0001 0.0000 0.6071 0.0111 0.0004 0.0001 0.0000 0.6538 0.0108 0.0004 0.0002 0.0000 0.7005 0.0105 0.0005 0.0002 0.0000 0.7473 0.0102 0.0005 0.0002 0.0000 0.7940 0.0100 0.0006 0.0003 0.0000 0.8407 0.0097 0.0007 0.0003 0.0000 0.8874 0.0094 0.0007 0.0004 0.0000 0.9341 0.0092 0.0008 0.0004 0.0000 0.9808 0.0089 0.0009 0.0004 0.0000 1.0275 0.0087 0.0009 0.0004 0.0000 1.0742 0.0084 0.0010 0.0005 0.0000 1.1209 0.0082 0.0011 0.0006 0.0000 1.1676 0.0079 0.0012 0.0007 0.0000 1.2143 0.0077 0.0012 0.0007 0.0000 1.2610 0.0075 0.0013 0.0007 0.0000 1.3077 0.0072 0.0014 0.0008 0.0000 South Bioretention 1 12/22/2023 4:00:47 PM Page 7 1.3544 0.0070 0.0015 0.0009 0.0000 1.4011 0.0068 0.0016 0.0011 0.0000 1.4478 0.0066 0.0017 0.0012 0.0000 1.4945 0.0063 0.0018 0.0012 0.0000 1.5412 0.0061 0.0019 0.0013 0.0000 1.5879 0.0059 0.0021 0.0014 0.0000 1.6346 0.0057 0.0022 0.0016 0.0000 1.6813 0.0055 0.0023 0.0017 0.0000 1.7280 0.0053 0.0024 0.0018 0.0000 1.7747 0.0051 0.0025 0.0019 0.0000 1.8214 0.0049 0.0027 0.0019 0.0000 1.8681 0.0047 0.0028 0.0021 0.0000 1.9148 0.0046 0.0029 0.0022 0.0000 1.9615 0.0044 0.0031 0.0024 0.0000 2.0082 0.0042 0.0032 0.0024 0.0000 2.0549 0.0040 0.0034 0.0024 0.0000 2.1016 0.0039 0.0035 0.0024 0.0000 2.1484 0.0037 0.0037 0.0024 0.0000 2.1951 0.0035 0.0038 0.0024 0.0000 2.2418 0.0034 0.0040 0.0024 0.0000 2.2885 0.0032 0.0042 0.0024 0.0000 2.3352 0.0031 0.0043 0.0024 0.0000 2.3819 0.0029 0.0045 0.0024 0.0000 2.4286 0.0028 0.0047 0.0024 0.0000 2.4753 0.0026 0.0049 0.0024 0.0000 2.5220 0.0025 0.0051 0.0045 0.0000 2.5687 0.0024 0.0053 0.0045 0.0000 2.6154 0.0022 0.0055 0.0045 0.0000 2.6621 0.0021 0.0057 0.0045 0.0000 2.7088 0.0020 0.0059 0.0045 0.0000 2.7555 0.0019 0.0061 0.0045 0.0000 2.8022 0.0018 0.0064 0.0045 0.0000 2.8489 0.0016 0.0066 0.0045 0.0000 2.8956 0.0015 0.0069 0.0045 0.0000 2.9423 0.0014 0.0071 0.0045 0.0000 2.9890 0.0013 0.0073 0.0045 0.0000 3.0357 0.0012 0.0076 0.0045 0.0000 3.0824 0.0011 0.0079 0.0045 0.0000 3.1291 0.0011 0.0081 0.0045 0.0000 3.1758 0.0010 0.0084 0.0045 0.0000 3.2225 0.0009 0.0087 0.0045 0.0000 3.2500 0.0008 0.0089 0.0045 0.0000 Bioretention Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)To Amended(cfs)Infilt(cfs) 3.2500 0.0149050.008866 0.0000 0.0029 0.0000 3.2967 0.0152350.009570 0.0000 0.0029 0.0000 3.3434 0.0155680.010289 0.0000 0.0030 0.0000 3.3901 0.0159050.011024 0.0000 0.0031 0.0000 3.4368 0.0162460.011775 0.0000 0.0031 0.0000 3.4835 0.0165900.012541 0.0000 0.0032 0.0000 3.5302 0.0169380.013324 0.0000 0.0033 0.0000 3.5769 0.0172900.014124 0.0000 0.0034 0.0000 3.6236 0.0176450.014939 0.0000 0.0034 0.0000 3.6703 0.0180030.015772 0.0000 0.0035 0.0000 3.7170 0.0183660.016621 0.0000 0.0036 0.0000 3.7637 0.0187320.017488 0.0171 0.0037 0.0000 3.8104 0.0191010.018371 0.1574 0.0037 0.0000 South Bioretention 1 12/22/2023 4:00:47 PM Page 8 3.8571 0.0194740.019272 0.3694 0.0038 0.0000 3.9038 0.0198510.020190 0.6273 0.0039 0.0000 3.9505 0.0202320.021126 0.9111 0.0040 0.0000 3.9973 0.0206160.022080 1.2008 0.0040 0.0000 4.0440 0.0210030.023052 1.4761 0.0041 0.0000 4.0907 0.0213940.024042 1.7188 0.0042 0.0000 4.1374 0.0217890.025050 1.9155 0.0043 0.0000 4.1841 0.0221870.026077 2.0620 0.0043 0.0000 4.2308 0.0225890.027123 2.1668 0.0044 0.0000 4.2500 0.0227560.027559 2.2875 0.0045 0.0000 South Bioretention 1 12/22/2023 4:00:47 PM Page 9 Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 South Bioretention 1 12/22/2023 4:00:47 PM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.112 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0 Total Impervious Area: 0.112 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.000095 5 year 0.000144 10 year 0.000184 25 year 0.000243 50 year 0.000295 100 year 0.000354 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.028657 5 year 0.047075 10 year 0.059295 25 year 0.074284 50 year 0.084987 100 year 0.095243 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.000 0.031 1950 0.000 0.046 1951 0.000 0.039 1952 0.000 0.025 1953 0.000 0.018 1954 0.000 0.015 1955 0.000 0.036 1956 0.000 0.031 1957 0.000 0.049 1958 0.000 0.022 South Bioretention 1 12/22/2023 4:01:29 PM Page 11 1959 0.000 0.026 1960 0.000 0.040 1961 0.000 0.018 1962 0.000 0.009 1963 0.000 0.019 1964 0.000 0.016 1965 0.000 0.020 1966 0.000 0.015 1967 0.000 0.050 1968 0.000 0.022 1969 0.000 0.035 1970 0.000 0.025 1971 0.000 0.038 1972 0.000 0.040 1973 0.000 0.017 1974 0.000 0.016 1975 0.000 0.046 1976 0.000 0.032 1977 0.000 0.015 1978 0.000 0.028 1979 0.000 0.007 1980 0.000 0.054 1981 0.000 0.035 1982 0.000 0.067 1983 0.000 0.023 1984 0.000 0.015 1985 0.000 0.020 1986 0.000 0.039 1987 0.000 0.045 1988 0.000 0.016 1989 0.000 0.008 1990 0.000 0.083 1991 0.000 0.070 1992 0.000 0.021 1993 0.000 0.016 1994 0.000 0.003 1995 0.000 0.028 1996 0.001 0.045 1997 0.000 0.035 1998 0.000 0.027 1999 0.000 0.033 2000 0.000 0.022 2001 0.000 0.018 2002 0.000 0.059 2003 0.000 0.009 2004 0.000 0.089 2005 0.000 0.038 2006 0.000 0.027 2007 0.001 0.083 2008 0.000 0.068 2009 0.000 0.047 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0009 0.0890 2 0.0006 0.0827 3 0.0005 0.0827 South Bioretention 1 12/22/2023 4:01:29 PM Page 12 4 0.0002 0.0698 5 0.0002 0.0684 6 0.0001 0.0670 7 0.0001 0.0585 8 0.0001 0.0543 9 0.0001 0.0499 10 0.0001 0.0485 11 0.0001 0.0475 12 0.0001 0.0462 13 0.0001 0.0460 14 0.0001 0.0453 15 0.0001 0.0448 16 0.0001 0.0402 17 0.0001 0.0398 18 0.0001 0.0392 19 0.0001 0.0391 20 0.0001 0.0383 21 0.0001 0.0378 22 0.0001 0.0358 23 0.0001 0.0350 24 0.0001 0.0350 25 0.0001 0.0347 26 0.0001 0.0328 27 0.0001 0.0322 28 0.0001 0.0315 29 0.0001 0.0310 30 0.0001 0.0278 31 0.0001 0.0276 32 0.0001 0.0274 33 0.0001 0.0265 34 0.0001 0.0256 35 0.0001 0.0248 36 0.0001 0.0247 37 0.0001 0.0229 38 0.0001 0.0224 39 0.0001 0.0223 40 0.0001 0.0216 41 0.0001 0.0205 42 0.0001 0.0197 43 0.0001 0.0197 44 0.0001 0.0185 45 0.0001 0.0182 46 0.0001 0.0181 47 0.0001 0.0178 48 0.0001 0.0174 49 0.0001 0.0165 50 0.0001 0.0164 51 0.0001 0.0161 52 0.0001 0.0157 53 0.0001 0.0154 54 0.0001 0.0151 55 0.0001 0.0147 56 0.0001 0.0146 57 0.0001 0.0094 58 0.0001 0.0094 59 0.0001 0.0080 60 0.0001 0.0070 61 0.0001 0.0032 South Bioretention 1 12/22/2023 4:01:29 PM Page 13 South Bioretention 1 12/22/2023 4:01:29 PM Page 14 Duration Flows Flow(cfs) Predev Mit Percentage Pass/Fail 0.0000 3086 903677 29283 Fail 0.0001 2710 895977 33061 Fail 0.0001 2464 890844 36154 Fail 0.0001 2145 883571 41192 Fail 0.0001 1952 878866 45023 Fail 0.0001 1687 872021 51690 Fail 0.0001 1520 867744 57088 Fail 0.0001 1330 861541 64777 Fail 0.0001 1205 857263 71142 Fail 0.0001 1009 851060 84346 Fail 0.0001 874 846996 96910 Fail 0.0001 672 841008 125150 Fail 0.0001 577 837158 145088 Fail 0.0001 446 832024 186552 Fail 0.0001 368 828816 225221 Fail 0.0001 250 823897 329558 Fail 0.0001 160 820902 513063 Fail 0.0001 36 816197 2267213 Fail 0.0001 26 813202 3127700 Fail 0.0001 26 808711 3110426 Fail 0.0001 26 805930 3099730 Fail 0.0001 26 801652 3083276 Fail 0.0001 25 798872 3195488 Fail 0.0001 25 794808 3179232 Fail 0.0001 24 792455 3301895 Fail 0.0001 23 788605 3428717 Fail 0.0001 23 786252 3418486 Fail 0.0001 23 782616 3402678 Fail 0.0001 22 780263 3546650 Fail 0.0001 22 776841 3531095 Fail 0.0001 22 774702 3521372 Fail 0.0001 21 771280 3672761 Fail 0.0001 21 769141 3662576 Fail 0.0001 21 765719 3646280 Fail 0.0001 21 763580 3636095 Fail 0.0001 19 759944 3999705 Fail 0.0001 19 756736 3982821 Fail 0.0001 18 752030 4177944 Fail 0.0001 18 748822 4160122 Fail 0.0001 18 744330 4135166 Fail 0.0001 16 741336 4633350 Fail 0.0002 16 736630 4603937 Fail 0.0002 16 733636 4585225 Fail 0.0002 16 728930 4555812 Fail 0.0002 16 724653 4529081 Fail 0.0002 15 718022 4786813 Fail 0.0002 15 713530 4756866 Fail 0.0002 15 706900 4712666 Fail 0.0002 14 702408 5017200 Fail 0.0002 13 696633 5358715 Fail 0.0002 13 694280 5340615 Fail 0.0002 13 691714 5320876 Fail 0.0002 13 690003 5307715 Fail 0.0002 13 687436 5287969 Fail South Bioretention 1 12/22/2023 4:01:29 PM Page 15 0.0002 13 685725 5274807 Fail 0.0002 12 683158 5692983 Fail 0.0002 12 681661 5680508 Fail 0.0002 12 679094 5659116 Fail 0.0002 11 677597 6159972 Fail 0.0002 11 675244 6138581 Fail 0.0002 11 673533 6123027 Fail 0.0002 11 671181 6101645 Fail 0.0002 10 669683 6696829 Fail 0.0002 10 667117 6671170 Fail 0.0002 10 665619 6656190 Fail 0.0002 9 663481 7372011 Fail 0.0002 9 661983 7355366 Fail 0.0002 9 660058 7333977 Fail 0.0002 9 658561 7317344 Fail 0.0002 8 656636 8207950 Fail 0.0002 8 655353 8191912 Fail 0.0002 8 653428 8167850 Fail 0.0002 8 652145 8151812 Fail 0.0002 8 650220 8127750 Fail 0.0002 8 648936 8111700 Fail 0.0002 8 646797 8084962 Fail 0.0002 8 645728 8071600 Fail 0.0002 8 643803 8047537 Fail 0.0002 8 642520 8031500 Fail 0.0002 8 640595 8007437 Fail 0.0002 8 639525 7994062 Fail 0.0003 8 637814 7972675 Fail 0.0003 8 636531 7956637 Fail 0.0003 8 634820 7935250 Fail 0.0003 8 633536 7919200 Fail 0.0003 8 631825 7897812 Fail 0.0003 8 630542 7881775 Fail 0.0003 8 628831 7860387 Fail 0.0003 8 627761 7847012 Fail 0.0003 8 626050 7825625 Fail 0.0003 8 624981 7812262 Fail 0.0003 8 623270 7790875 Fail 0.0003 8 622200 7777500 Fail 0.0003 8 620489 7756112 Fail 0.0003 8 619420 7742750 Fail 0.0003 8 617709 7721362 Fail 0.0003 8 616639 7707987 Fail 0.0003 8 614928 7686600 Fail 0.0003 8 613859 7673237 Fail 0.0003 8 612361 7654512 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. South Bioretention 1 12/22/2023 4:01:29 PM Page 16 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. South Bioretention 1 12/22/2023 4:01:29 PM Page 17 LID Report South Bioretention 1 12/22/2023 4:01:56 PM Page 18 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. South Bioretention 1 12/22/2023 4:01:56 PM Page 19 Appendix Predeveloped Schematic South Bioretention 1 12/22/2023 4:01:58 PM Page 20 Mitigated Schematic South Bioretention 1 12/22/2023 4:02:00 PM Page 21 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 South Bioretention 1.wdm MESSU 25 PreSouth Bioretention 1.MES 27 PreSouth Bioretention 1.L61 28 PreSouth Bioretention 1.L62 30 POCSouth Bioretention 11.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 South Half Bioretention 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 A/B, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 1 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO South Bioretention 1 12/22/2023 4:02:00 PM Page 22 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 1 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 1 0 5 2 400 0.05 0.3 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 1 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 1 0.2 0.5 0.35 0 0.7 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 1 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 South Bioretention 1 12/22/2023 4:02:00 PM Page 23 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Half Bioretention 1*** PERLND 1 0.112 COPY 501 12 PERLND 1 0.112 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC South Bioretention 1 12/22/2023 4:02:00 PM Page 24 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN South Bioretention 1 12/22/2023 4:02:00 PM Page 25 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 South Bioretention 1.wdm MESSU 25 MitSouth Bioretention 1.MES 27 MitSouth Bioretention 1.L61 28 MitSouth Bioretention 1.L62 30 POCSouth Bioretention 11.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 IMPLND 1 RCHRES 1 RCHRES 2 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Surface retention 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* END PRINT-INFO South Bioretention 1 12/22/2023 4:02:00 PM Page 26 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 South Bioretention 1 12/22/2023 4:02:00 PM Page 27 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Bioretention 1*** IMPLND 1 0.112 RCHRES 1 5 ******Routing****** IMPLND 1 0.112 COPY 1 15 RCHRES 1 1 RCHRES 2 8 RCHRES 2 1 COPY 501 16 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Surface retentio-020 3 1 1 1 28 0 1 2 Bioretention 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 6 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.0 0.0 2 2 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT South Bioretention 1 12/22/2023 4:02:00 PM Page 28 *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 6.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 2 71 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.014905 0.000000 0.000000 0.046703 0.014712 0.000020 0.000000 0.093407 0.014388 0.000042 0.000000 0.140110 0.014068 0.000065 0.000000 0.186813 0.013751 0.000091 0.000001 0.233516 0.013437 0.000119 0.000003 0.280220 0.013128 0.000147 0.000007 0.326923 0.012821 0.000176 0.000014 0.373626 0.012519 0.000208 0.000025 0.420330 0.012220 0.000242 0.000038 0.467033 0.011925 0.000278 0.000056 0.513736 0.011633 0.000317 0.000077 0.560440 0.011345 0.000358 0.000103 0.607143 0.011060 0.000402 0.000134 0.653846 0.010780 0.000448 0.000155 0.700549 0.010502 0.000498 0.000170 0.747253 0.010229 0.000550 0.000210 0.793956 0.009958 0.000604 0.000257 0.840659 0.009692 0.000662 0.000308 0.887363 0.009429 0.000723 0.000366 0.934066 0.009170 0.000787 0.000369 0.980769 0.008914 0.000854 0.000389 1.027473 0.008662 0.000925 0.000430 1.074176 0.008414 0.000998 0.000499 1.120879 0.008169 0.001076 0.000576 1.167582 0.007928 0.001156 0.000658 1.214286 0.007690 0.001240 0.000701 1.260989 0.007456 0.001328 0.000748 1.307692 0.007226 0.001420 0.000845 1.354396 0.006999 0.001515 0.000948 1.401099 0.006776 0.001615 0.001059 1.447802 0.006556 0.001718 0.001165 1.494505 0.006340 0.001825 0.001178 1.541209 0.006128 0.001937 0.001304 1.587912 0.005919 0.002052 0.001437 1.634615 0.005714 0.002172 0.001579 1.681319 0.005512 0.002296 0.001729 1.728022 0.005314 0.002425 0.001778 1.774725 0.005120 0.002546 0.001887 1.821429 0.004929 0.002671 0.001897 1.868132 0.004742 0.002800 0.002053 1.914835 0.004558 0.002933 0.002227 1.961538 0.004378 0.003071 0.002410 2.008242 0.004202 0.003214 0.002431 2.054945 0.004029 0.003360 0.002431 2.101648 0.003860 0.003512 0.002431 2.148352 0.003695 0.003668 0.002431 2.195055 0.003533 0.003828 0.002431 2.241758 0.003374 0.003994 0.002431 2.288462 0.003220 0.004164 0.002431 2.335165 0.003068 0.004340 0.002431 2.381868 0.002921 0.004520 0.002431 2.428571 0.002777 0.004705 0.002431 2.475275 0.002637 0.004895 0.002431 2.521978 0.002500 0.005091 0.004456 2.568681 0.002367 0.005292 0.004456 South Bioretention 1 12/22/2023 4:02:00 PM Page 29 2.615385 0.002238 0.005498 0.004456 2.662088 0.002112 0.005710 0.004456 2.708791 0.001989 0.005927 0.004456 2.755495 0.001871 0.006150 0.004456 2.802198 0.001756 0.006378 0.004456 2.848901 0.001644 0.006612 0.004456 2.895604 0.001536 0.006852 0.004456 2.942308 0.001432 0.007097 0.004456 2.989011 0.001332 0.007349 0.004456 3.035714 0.001235 0.007606 0.004456 3.082418 0.001141 0.007870 0.004456 3.129121 0.001051 0.008139 0.004456 3.175824 0.000965 0.008415 0.004456 3.222527 0.000882 0.008697 0.004456 3.250000 0.000803 0.008958 0.004456 END FTABLE 2 FTABLE 1 23 6 Depth Area Volume Outflow1 Outflow2 outflow 3 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.000803 0.000000 0.000000 0.000000 0.000000 0.046703 0.015235 0.000704 0.000000 0.002911 0.000000 0.093407 0.015568 0.001423 0.000000 0.002987 0.000000 0.140110 0.015905 0.002158 0.000000 0.003063 0.000000 0.186813 0.016246 0.002909 0.000000 0.003138 0.000000 0.233516 0.016590 0.003676 0.000000 0.003214 0.000000 0.280220 0.016938 0.004459 0.000000 0.003290 0.000000 0.326923 0.017290 0.005258 0.000000 0.003365 0.000000 0.373626 0.017645 0.006074 0.000000 0.003441 0.000000 0.420330 0.018003 0.006906 0.000000 0.003517 0.000000 0.467033 0.018366 0.007755 0.000000 0.003592 0.000000 0.513736 0.018732 0.008622 0.017087 0.003668 0.000000 0.560440 0.019101 0.009505 0.157374 0.003744 0.000000 0.607143 0.019474 0.010406 0.369426 0.003819 0.000000 0.653846 0.019851 0.011324 0.627270 0.003895 0.000000 0.700549 0.020232 0.012260 0.911089 0.003971 0.000000 0.747253 0.020616 0.013214 1.200769 0.004046 0.000000 0.793956 0.021003 0.014186 1.476083 0.004122 0.000000 0.840659 0.021394 0.015176 1.718754 0.004198 0.000000 0.887363 0.021789 0.016184 1.915531 0.004274 0.000000 0.934066 0.022187 0.017211 2.061968 0.004349 0.000000 0.980769 0.022589 0.018257 2.166777 0.004425 0.000000 1.000000 0.022756 0.018693 2.287491 0.004456 0.000000 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 1 EVAP ENGL 0.5 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 2 HYDR RO 1 1 1 WDM 1004 FLOW ENGL REPL RCHRES 2 HYDR STAGE 1 1 1 WDM 1005 STAG ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1006 STAG ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1007 FLOW ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL South Bioretention 1 12/22/2023 4:02:00 PM Page 30 END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 8 RCHRES OFLOW OVOL 2 RCHRES INFLOW IVOL END MASS-LINK 8 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN South Bioretention 1 12/22/2023 4:02:00 PM Page 31 Predeveloped HSPF Message File South Bioretention 1 12/22/2023 4:02:00 PM Page 32 Mitigated HSPF Message File South Bioretention 1 12/22/2023 4:02:00 PM Page 33 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT South Bioretention 2 12/22/2023 4:13:13 PM Page 2 General Model Information Project Name: South Bioretention 2 Site Name: Federal Way O&M Site Address: Site 1 City: Report Date: 12/22/2023 Gage: Seatac Data Start: 1948/10/01 Data End: 2009/09/30 Timestep: 15 Minute Precip Scale: 1.000 Version Date: 2018/10/10 Version: 4.2.16 POC Thresholds Low Flow Threshold for POC1: 50 Percent of the 2 Year High Flow Threshold for POC1: 50 Year South Bioretention 2 12/22/2023 4:13:13 PM Page 3 Landuse Basin Data Predeveloped Land Use South Half Bioretention 1 Bypass: No GroundWater: No Pervious Land Use acre A B, Forest, Flat 0.698 Pervious Total 0.698 Impervious Land Use acre Impervious Total 0 Basin Total 0.698 Element Flows To: Surface Interflow Groundwater South Bioretention 2 12/22/2023 4:13:13 PM Page 4 Mitigated Land Use South Bioretention 1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 0.081 Pervious Total 0.081 Impervious Land Use acre ROADS FLAT 0.617 Impervious Total 0.617 Basin Total 0.698 Element Flows To: Surface Interflow Groundwater Surface retention 1 South Bioretention 2 12/22/2023 4:13:13 PM Page 5 Routing Elements Predeveloped Routing South Bioretention 2 12/22/2023 4:13:13 PM Page 6 Mitigated Routing Bioretention 1 Bottom Length: 28.00 ft. Bottom Width: 10.00 ft. Material thickness of first layer: 0.25 Material type for first layer: ASTM 100 Material thickness of second layer: 1.5 Material type for second layer: SMMWW 12 in/hr Material thickness of third layer: 1.5 Material type for third layer: GRAVEL Underdrain used Underdrain Diameter (feet): 0.5 Orifice Diameter (in.): 1.007 Offset (in.): 0 Flow Through Underdrain (ac-ft.): 91.237 Total Outflow (ac-ft.): 99.78 Percent Through Underdrain: 91.44 Discharge Structure Riser Height: 0.5 ft. Riser Diameter: 12 in. Element Flows To: Outlet 1 Outlet 2 Bioretention Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.0322 0.0000 0.0000 0.0000 0.0467 0.0319 0.0002 0.0000 0.0000 0.0934 0.0314 0.0003 0.0000 0.0000 0.1401 0.0309 0.0005 0.0000 0.0000 0.1868 0.0304 0.0007 0.0000 0.0000 0.2335 0.0299 0.0008 0.0000 0.0000 0.2802 0.0295 0.0010 0.0001 0.0000 0.3269 0.0290 0.0012 0.0001 0.0000 0.3736 0.0285 0.0014 0.0002 0.0000 0.4203 0.0280 0.0015 0.0003 0.0000 0.4670 0.0276 0.0017 0.0004 0.0000 0.5137 0.0271 0.0019 0.0006 0.0000 0.5604 0.0267 0.0021 0.0008 0.0000 0.6071 0.0262 0.0023 0.0011 0.0000 0.6538 0.0258 0.0025 0.0012 0.0000 0.7005 0.0253 0.0028 0.0014 0.0000 0.7473 0.0249 0.0030 0.0017 0.0000 0.7940 0.0244 0.0032 0.0021 0.0000 0.8407 0.0240 0.0035 0.0025 0.0000 0.8874 0.0236 0.0037 0.0029 0.0000 0.9341 0.0232 0.0040 0.0030 0.0000 0.9808 0.0227 0.0042 0.0031 0.0000 1.0275 0.0223 0.0045 0.0034 0.0000 1.0742 0.0219 0.0048 0.0040 0.0000 1.1209 0.0215 0.0051 0.0046 0.0000 1.1676 0.0211 0.0053 0.0053 0.0000 1.2143 0.0207 0.0056 0.0056 0.0000 1.2610 0.0203 0.0059 0.0060 0.0000 1.3077 0.0199 0.0063 0.0068 0.0000 South Bioretention 2 12/22/2023 4:13:13 PM Page 7 1.3544 0.0195 0.0066 0.0076 0.0000 1.4011 0.0191 0.0069 0.0085 0.0000 1.4478 0.0187 0.0072 0.0093 0.0000 1.4945 0.0183 0.0076 0.0094 0.0000 1.5412 0.0179 0.0079 0.0104 0.0000 1.5879 0.0176 0.0083 0.0115 0.0000 1.6346 0.0172 0.0086 0.0126 0.0000 1.6813 0.0168 0.0090 0.0129 0.0000 1.7280 0.0165 0.0094 0.0142 0.0000 1.7747 0.0161 0.0097 0.0144 0.0000 1.8214 0.0157 0.0101 0.0145 0.0000 1.8681 0.0154 0.0105 0.0148 0.0000 1.9148 0.0150 0.0108 0.0150 0.0000 1.9615 0.0147 0.0112 0.0154 0.0000 2.0082 0.0143 0.0116 0.0155 0.0000 2.0549 0.0140 0.0120 0.0162 0.0000 2.1016 0.0137 0.0124 0.0165 0.0000 2.1484 0.0133 0.0128 0.0172 0.0000 2.1951 0.0130 0.0132 0.0180 0.0000 2.2418 0.0127 0.0137 0.0194 0.0000 2.2885 0.0124 0.0141 0.0194 0.0000 2.3352 0.0120 0.0145 0.0194 0.0000 2.3819 0.0117 0.0150 0.0194 0.0000 2.4286 0.0114 0.0155 0.0194 0.0000 2.4753 0.0111 0.0159 0.0194 0.0000 2.5220 0.0108 0.0164 0.0213 0.0000 2.5687 0.0105 0.0169 0.0226 0.0000 2.6154 0.0102 0.0174 0.0236 0.0000 2.6621 0.0099 0.0179 0.0245 0.0000 2.7088 0.0096 0.0184 0.0252 0.0000 2.7555 0.0093 0.0189 0.0260 0.0000 2.8022 0.0091 0.0195 0.0267 0.0000 2.8489 0.0088 0.0200 0.0273 0.0000 2.8956 0.0085 0.0205 0.0280 0.0000 2.9423 0.0082 0.0211 0.0286 0.0000 2.9890 0.0080 0.0217 0.0293 0.0000 3.0357 0.0077 0.0222 0.0299 0.0000 3.0824 0.0074 0.0228 0.0305 0.0000 3.1291 0.0072 0.0234 0.0310 0.0000 3.1758 0.0069 0.0240 0.0316 0.0000 3.2225 0.0067 0.0246 0.0322 0.0000 3.2500 0.0064 0.0250 0.0327 0.0000 Bioretention Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)To Amended(cfs)Infilt(cfs) 3.2500 0.0322 0.0250 0.0000 0.0233 0.0000 3.2967 0.0327 0.0265 0.0000 0.0233 0.0000 3.3434 0.0332 0.0281 0.0000 0.0239 0.0000 3.3901 0.0337 0.0296 0.0000 0.0245 0.0000 3.4368 0.0342 0.0312 0.0000 0.0251 0.0000 3.4835 0.0347 0.0328 0.0000 0.0257 0.0000 3.5302 0.0352 0.0344 0.0000 0.0263 0.0000 3.5769 0.0357 0.0361 0.0000 0.0269 0.0000 3.6236 0.0362 0.0378 0.0000 0.0275 0.0000 3.6703 0.0368 0.0395 0.0000 0.0281 0.0000 3.7170 0.0373 0.0412 0.0000 0.0287 0.0000 3.7637 0.0378 0.0430 0.0171 0.0293 0.0000 3.8104 0.0384 0.0447 0.1574 0.0300 0.0000 South Bioretention 2 12/22/2023 4:13:13 PM Page 8 3.8571 0.0389 0.0466 0.3694 0.0306 0.0000 3.9038 0.0395 0.0484 0.6273 0.0312 0.0000 3.9505 0.0400 0.0502 0.9111 0.0318 0.0000 3.9973 0.0406 0.0521 1.2008 0.0322 0.0000 4.0440 0.0411 0.0540 1.4761 0.0322 0.0000 4.0907 0.0417 0.0560 1.7188 0.0322 0.0000 4.1374 0.0422 0.0579 1.9155 0.0322 0.0000 4.1841 0.0428 0.0599 2.0620 0.0322 0.0000 4.2308 0.0434 0.0619 2.1668 0.0322 0.0000 4.2500 0.0436 0.0628 2.2875 0.0322 0.0000 South Bioretention 2 12/22/2023 4:13:13 PM Page 9 Surface retention 1 Element Flows To: Outlet 1 Outlet 2 Bioretention 1 South Bioretention 2 12/22/2023 4:13:13 PM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area: 0.698 Total Impervious Area: 0 Mitigated Landuse Totals for POC #1 Total Pervious Area: 0.081 Total Impervious Area: 0.617 Flow Frequency Method: Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.000592 5 year 0.000896 10 year 0.001144 25 year 0.001516 50 year 0.00184 100 year 0.002208 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.182198 5 year 0.262103 10 year 0.311736 25 year 0.370518 50 year 0.411571 100 year 0.450446 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.000 0.186 1950 0.001 0.294 1951 0.001 0.185 1952 0.001 0.134 1953 0.001 0.144 1954 0.001 0.127 1955 0.001 0.177 1956 0.001 0.157 1957 0.001 0.237 1958 0.001 0.115 South Bioretention 2 12/22/2023 4:13:52 PM Page 11 1959 0.001 0.133 1960 0.001 0.181 1961 0.001 0.164 1962 0.001 0.084 1963 0.001 0.117 1964 0.001 0.146 1965 0.001 0.121 1966 0.001 0.160 1967 0.001 0.271 1968 0.001 0.236 1969 0.001 0.207 1970 0.001 0.195 1971 0.001 0.192 1972 0.003 0.234 1973 0.001 0.114 1974 0.001 0.133 1975 0.001 0.226 1976 0.001 0.170 1977 0.000 0.110 1978 0.001 0.228 1979 0.000 0.104 1980 0.001 0.254 1981 0.001 0.235 1982 0.001 0.339 1983 0.001 0.262 1984 0.001 0.102 1985 0.001 0.232 1986 0.001 0.186 1987 0.001 0.213 1988 0.001 0.113 1989 0.001 0.048 1990 0.001 0.412 1991 0.001 0.346 1992 0.001 0.148 1993 0.000 0.109 1994 0.001 0.044 1995 0.001 0.162 1996 0.004 0.224 1997 0.001 0.167 1998 0.001 0.154 1999 0.001 0.400 2000 0.001 0.185 2001 0.001 0.162 2002 0.001 0.296 2003 0.001 0.105 2004 0.001 0.428 2005 0.001 0.182 2006 0.001 0.150 2007 0.006 0.374 2008 0.001 0.348 2009 0.001 0.232 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0058 0.4284 2 0.0039 0.4116 3 0.0029 0.4004 South Bioretention 2 12/22/2023 4:13:52 PM Page 12 4 0.0011 0.3742 5 0.0010 0.3480 6 0.0009 0.3465 7 0.0009 0.3393 8 0.0006 0.2959 9 0.0006 0.2944 10 0.0006 0.2709 11 0.0006 0.2621 12 0.0006 0.2539 13 0.0006 0.2368 14 0.0006 0.2358 15 0.0006 0.2349 16 0.0006 0.2340 17 0.0006 0.2323 18 0.0006 0.2321 19 0.0006 0.2275 20 0.0006 0.2259 21 0.0006 0.2238 22 0.0006 0.2131 23 0.0006 0.2070 24 0.0006 0.1953 25 0.0006 0.1920 26 0.0006 0.1863 27 0.0006 0.1856 28 0.0006 0.1848 29 0.0006 0.1848 30 0.0006 0.1816 31 0.0005 0.1811 32 0.0005 0.1772 33 0.0005 0.1697 34 0.0005 0.1667 35 0.0005 0.1641 36 0.0005 0.1621 37 0.0005 0.1620 38 0.0005 0.1601 39 0.0005 0.1570 40 0.0005 0.1535 41 0.0005 0.1502 42 0.0005 0.1484 43 0.0005 0.1455 44 0.0005 0.1440 45 0.0005 0.1341 46 0.0005 0.1331 47 0.0005 0.1325 48 0.0005 0.1269 49 0.0005 0.1205 50 0.0005 0.1167 51 0.0005 0.1151 52 0.0005 0.1141 53 0.0005 0.1134 54 0.0005 0.1095 55 0.0005 0.1090 56 0.0005 0.1053 57 0.0005 0.1043 58 0.0005 0.1022 59 0.0005 0.0840 60 0.0004 0.0483 61 0.0004 0.0436 South Bioretention 2 12/22/2023 4:13:52 PM Page 13 South Bioretention 2 12/22/2023 4:13:52 PM Page 14 Duration Flows Flow(cfs) Predev Mit Percentage Pass/Fail 0.0003 3037 747111 24600 Fail 0.0003 2727 738769 27090 Fail 0.0003 2396 731283 30520 Fail 0.0003 2152 724225 33653 Fail 0.0004 1915 717166 37449 Fail 0.0004 1696 710750 41907 Fail 0.0004 1485 703905 47401 Fail 0.0004 1330 697275 52426 Fail 0.0004 1177 691072 58714 Fail 0.0004 1009 684655 67854 Fail 0.0005 849 679094 79987 Fail 0.0005 678 673961 99404 Fail 0.0005 553 668828 120945 Fail 0.0005 448 664122 148241 Fail 0.0005 354 659203 186215 Fail 0.0005 255 654711 256749 Fail 0.0005 135 650006 481485 Fail 0.0006 36 645514 1793094 Fail 0.0006 26 641236 2466292 Fail 0.0006 26 636958 2449838 Fail 0.0006 26 632895 2434211 Fail 0.0006 26 628617 2417757 Fail 0.0006 25 624981 2499924 Fail 0.0007 25 621772 2487088 Fail 0.0007 24 618136 2575566 Fail 0.0007 23 615142 2674530 Fail 0.0007 23 611720 2659652 Fail 0.0007 23 608297 2644769 Fail 0.0007 22 605303 2751377 Fail 0.0007 22 602309 2737768 Fail 0.0008 22 599314 2724154 Fail 0.0008 21 596320 2839619 Fail 0.0008 21 593111 2824338 Fail 0.0008 21 590331 2811100 Fail 0.0008 21 587550 2797857 Fail 0.0008 19 584984 3078863 Fail 0.0009 19 582203 3064226 Fail 0.0009 18 579636 3220200 Fail 0.0009 18 577284 3207133 Fail 0.0009 17 574931 3381947 Fail 0.0009 16 572578 3578612 Fail 0.0009 16 570012 3562575 Fail 0.0010 16 567659 3547868 Fail 0.0010 16 565520 3534500 Fail 0.0010 16 563381 3521131 Fail 0.0010 15 561242 3741613 Fail 0.0010 15 558889 3725926 Fail 0.0010 15 556537 3710246 Fail 0.0010 14 554612 3961514 Fail 0.0011 13 552259 4248146 Fail 0.0011 13 549906 4230046 Fail 0.0011 13 546912 4207015 Fail 0.0011 13 543917 4183976 Fail 0.0011 13 540709 4159300 Fail South Bioretention 2 12/22/2023 4:13:52 PM Page 15 0.0011 13 537714 4136261 Fail 0.0012 12 534720 4456000 Fail 0.0012 12 531726 4431050 Fail 0.0012 12 528731 4406091 Fail 0.0012 11 525737 4779427 Fail 0.0012 11 522742 4752200 Fail 0.0012 11 519748 4724981 Fail 0.0012 11 516326 4693872 Fail 0.0013 10 512262 5122620 Fail 0.0013 10 507770 5077700 Fail 0.0013 9 503492 5594355 Fail 0.0013 9 499428 5549200 Fail 0.0013 9 495151 5501677 Fail 0.0013 9 491301 5458900 Fail 0.0014 9 487665 5418500 Fail 0.0014 8 485312 6066400 Fail 0.0014 8 483601 6045012 Fail 0.0014 8 481890 6023625 Fail 0.0014 8 480392 6004900 Fail 0.0014 8 478895 5986187 Fail 0.0015 8 477184 5964800 Fail 0.0015 8 475687 5946087 Fail 0.0015 8 474190 5927375 Fail 0.0015 8 472692 5908650 Fail 0.0015 8 471195 5889937 Fail 0.0015 8 469698 5871225 Fail 0.0015 8 468415 5855187 Fail 0.0016 8 466918 5836475 Fail 0.0016 8 465420 5817750 Fail 0.0016 8 464137 5801712 Fail 0.0016 8 462640 5783000 Fail 0.0016 8 461356 5766950 Fail 0.0016 8 459859 5748237 Fail 0.0017 8 458576 5732200 Fail 0.0017 8 457079 5713487 Fail 0.0017 8 455795 5697437 Fail 0.0017 8 454512 5681400 Fail 0.0017 8 453229 5665362 Fail 0.0017 8 452159 5651987 Fail 0.0017 8 450876 5635950 Fail 0.0018 8 449593 5619912 Fail 0.0018 8 448523 5606537 Fail 0.0018 8 447240 5590500 Fail 0.0018 8 446170 5577125 Fail 0.0018 8 444887 5561087 Fail 0.0018 8 443604 5545050 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. South Bioretention 2 12/22/2023 4:13:52 PM Page 16 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. South Bioretention 2 12/22/2023 4:13:52 PM Page 17 LID Report South Bioretention 2 12/22/2023 4:14:20 PM Page 18 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. South Bioretention 2 12/22/2023 4:14:20 PM Page 19 Appendix Predeveloped Schematic South Bioretention 2 12/22/2023 4:14:22 PM Page 20 Mitigated Schematic South Bioretention 2 12/22/2023 4:14:24 PM Page 21 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 South Bioretention 2.wdm MESSU 25 PreSouth Bioretention 2.MES 27 PreSouth Bioretention 2.L61 28 PreSouth Bioretention 2.L62 30 POCSouth Bioretention 21.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 South Half Bioretention 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 A/B, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 1 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 1 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO South Bioretention 2 12/22/2023 4:14:24 PM Page 22 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 1 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 1 0 5 2 400 0.05 0.3 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 1 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 1 0.2 0.5 0.35 0 0.7 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 1 0 0 0 0 3 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 South Bioretention 2 12/22/2023 4:14:24 PM Page 23 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Half Bioretention 1*** PERLND 1 0.698 COPY 501 12 PERLND 1 0.698 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC South Bioretention 2 12/22/2023 4:14:24 PM Page 24 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN South Bioretention 2 12/22/2023 4:14:24 PM Page 25 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 South Bioretention 2.wdm MESSU 25 MitSouth Bioretention 2.MES 27 MitSouth Bioretention 2.L61 28 MitSouth Bioretention 2.L62 30 POCSouth Bioretention 21.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 RCHRES 1 RCHRES 2 COPY 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Surface retention 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR South Bioretention 2 12/22/2023 4:14:24 PM Page 26 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 South Bioretention 2 12/22/2023 4:14:24 PM Page 27 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** South Bioretention 1*** PERLND 16 0.081 RCHRES 1 2 IMPLND 1 0.617 RCHRES 1 5 ******Routing****** PERLND 16 0.081 COPY 1 12 IMPLND 1 0.617 COPY 1 15 RCHRES 1 1 RCHRES 2 8 RCHRES 2 1 COPY 501 16 RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Surface retentio-020 3 1 1 1 28 0 1 2 Bioretention 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 2 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 2 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 6 0 0 0 0 0 0 0 2 2 2 2 2 2 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 South Bioretention 2 12/22/2023 4:14:24 PM Page 28 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.0 0.0 2 2 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 6.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 2 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 2 71 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.032168 0.000000 0.000000 0.046703 0.031878 0.000155 0.000000 0.093407 0.031386 0.000315 0.000000 0.140110 0.030898 0.000481 0.000000 0.186813 0.030414 0.000653 0.000006 0.233516 0.029933 0.000832 0.000024 0.280220 0.029457 0.000999 0.000059 0.326923 0.028983 0.001172 0.000116 0.373626 0.028513 0.001351 0.000198 0.420330 0.028047 0.001535 0.000307 0.467033 0.027585 0.001725 0.000447 0.513736 0.027126 0.001922 0.000620 0.560440 0.026670 0.002124 0.000828 0.607143 0.026218 0.002333 0.001073 0.653846 0.025770 0.002547 0.001241 0.700549 0.025326 0.002769 0.001358 0.747253 0.024885 0.002996 0.001684 0.793956 0.024448 0.003230 0.002053 0.840659 0.024014 0.003470 0.002467 0.887363 0.023584 0.003717 0.002927 0.934066 0.023157 0.003971 0.002954 0.980769 0.022734 0.004232 0.003116 1.027473 0.022315 0.004499 0.003436 1.074176 0.021899 0.004773 0.003995 1.120879 0.021487 0.005055 0.004605 1.167582 0.021079 0.005343 0.005267 1.214286 0.020674 0.005638 0.005605 1.260989 0.020272 0.005941 0.005984 1.307692 0.019875 0.006251 0.006757 1.354396 0.019481 0.006568 0.007586 1.401099 0.019090 0.006893 0.008474 1.447802 0.018703 0.007226 0.009324 1.494505 0.018320 0.007565 0.009421 1.541209 0.017940 0.007913 0.010429 1.587912 0.017564 0.008269 0.011500 1.634615 0.017192 0.008632 0.012633 1.681319 0.016823 0.009003 0.012939 1.728022 0.016458 0.009382 0.014227 1.774725 0.016096 0.009733 0.014385 1.821429 0.015738 0.010092 0.014464 1.868132 0.015384 0.010458 0.014808 1.914835 0.015033 0.010832 0.014979 1.961538 0.014686 0.011214 0.015356 2.008242 0.014342 0.011603 0.015545 2.054945 0.014002 0.012000 0.016191 South Bioretention 2 12/22/2023 4:14:24 PM Page 29 2.101648 0.013666 0.012404 0.016514 2.148352 0.013333 0.012817 0.017193 2.195055 0.013004 0.013237 0.018021 2.241758 0.012678 0.013666 0.019444 2.288462 0.012356 0.014102 0.019444 2.335165 0.012038 0.014547 0.019444 2.381868 0.011723 0.015000 0.019444 2.428571 0.011412 0.015461 0.019444 2.475275 0.011105 0.015931 0.019444 2.521978 0.010801 0.016409 0.021280 2.568681 0.010500 0.016895 0.022578 2.615385 0.010204 0.017391 0.023596 2.662088 0.009910 0.017894 0.024463 2.708791 0.009621 0.018407 0.025245 2.755495 0.009335 0.018928 0.025975 2.802198 0.009053 0.019458 0.026671 2.848901 0.008774 0.019998 0.027342 2.895604 0.008499 0.020546 0.027994 2.942308 0.008227 0.021103 0.028629 2.989011 0.007960 0.021669 0.029251 3.035714 0.007695 0.022245 0.029859 3.082418 0.007435 0.022830 0.030456 3.129121 0.007177 0.023424 0.031043 3.175824 0.006924 0.024027 0.031622 3.222527 0.006674 0.024640 0.032196 3.250000 0.006428 0.025680 0.032653 END FTABLE 2 FTABLE 1 23 6 Depth Area Volume Outflow1 Outflow2 outflow 3 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.006428 0.000000 0.000000 0.000000 0.000000 0.046703 0.032665 0.001514 0.000000 0.023291 0.000000 0.093407 0.033166 0.003051 0.000000 0.023896 0.000000 0.140110 0.033671 0.004612 0.000000 0.024501 0.000000 0.186813 0.034178 0.006196 0.000000 0.025107 0.000000 0.233516 0.034690 0.007805 0.000000 0.025712 0.000000 0.280220 0.035205 0.009437 0.000000 0.026318 0.000000 0.326923 0.035724 0.011093 0.000000 0.026923 0.000000 0.373626 0.036246 0.012774 0.000000 0.027529 0.000000 0.420330 0.036772 0.014479 0.000000 0.028134 0.000000 0.467033 0.037302 0.016209 0.000000 0.028739 0.000000 0.513736 0.037835 0.017963 0.017087 0.029345 0.000000 0.560440 0.038372 0.019743 0.157374 0.029950 0.000000 0.607143 0.038912 0.021547 0.369426 0.030556 0.000000 0.653846 0.039456 0.023377 0.627270 0.031161 0.000000 0.700549 0.040004 0.025233 0.911089 0.031766 0.000000 0.747253 0.040555 0.027114 1.200769 0.032196 0.000000 0.793956 0.041110 0.029021 1.476083 0.032196 0.000000 0.840659 0.041668 0.030954 1.718754 0.032196 0.000000 0.887363 0.042230 0.032913 1.915531 0.032196 0.000000 0.934066 0.042796 0.034899 2.061968 0.032196 0.000000 0.980769 0.043365 0.036911 2.166777 0.032196 0.000000 1.000000 0.043601 0.037747 2.287491 0.032196 0.000000 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 2 PREC ENGL 1 RCHRES 1 EXTNL PREC WDM 1 EVAP ENGL 0.5 RCHRES 1 EXTNL POTEV WDM 1 EVAP ENGL 0.76 RCHRES 2 EXTNL POTEV South Bioretention 2 12/22/2023 4:14:24 PM Page 30 END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 2 HYDR RO 1 1 1 WDM 1004 FLOW ENGL REPL RCHRES 2 HYDR STAGE 1 1 1 WDM 1005 STAG ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1006 STAG ENGL REPL RCHRES 1 HYDR O 1 1 1 WDM 1007 FLOW ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 8 RCHRES OFLOW OVOL 2 RCHRES INFLOW IVOL END MASS-LINK 8 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN South Bioretention 2 12/22/2023 4:14:24 PM Page 31 Predeveloped HSPF Message File South Bioretention 2 12/22/2023 4:14:24 PM Page 32 Mitigated HSPF Message File South Bioretention 2 12/22/2023 4:14:24 PM Page 33 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 2215 North 30th Street Suite 300 Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX Preliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Appendix C Special Reports C-1.................... Geotechnical Engineering Report by Migizi Group, Inc., June 15, 2023 Geotechnical Engineering Report Steel Lake Operations & Maintenance Facility 31330 28th Avenue South Federal Way, WA 98003 Parcel Nos. 0921049009, -9026, -9075, - 9084, -9085, -9095, -9115, -9170, -9198, - 9239, -9240, -9250, -9313, -9314, -9315 June 15, 2023 prepared for: Helix Design Group, Inc. Attention: Jeff Ryan & Erik Prestegaard 6021 12th St E, #201 Tacoma, WA 98424 prepared by: Migizi Group, Inc. PO Box 44840 Tacoma, WA 98448 (253) 537-9400 MGI Project Z0390 i TABLE OF CONTENTS Page No. 1.0 SITE AND PROJECT DESCRIPTION ........................................................................................ 1 2.0 EXPLORATORY METHODS ...................................................................................................... 2 2.2 Auger Boring Procedures ............................................................................................... 2 3.0 SITE CONDITIONS ...................................................................................................................... 3 3.1 Surface Conditions ........................................................................................................... 3 3.2 Soil Conditions ................................................................................................................. 4 3.3 Groundwater Conditions ................................................................................................ 5 3.4 Seismic Conditions .......................................................................................................... 6 3.5 Liquefaction Potential ..................................................................................................... 7 3.6 Infiltration Conditions and Infiltration Rate ................................................................ 7 4.0 CONCLUSIONS AND RECOMMENDATIONS ..................................................................... 8 4.1 Site Preparation ................................................................................................................ 9 4.2 Spread Footings .............................................................................................................. 11 4.3 Structural Fill .................................................................................................................. 12 4.4 Slab-On-Grade Floors .................................................................................................... 13 4.5 Drainage Systems ........................................................................................................... 14 4.6 Asphalt Pavement .......................................................................................................... 14 5.0 RECOMMENDED ADDITIONAL SERVICES ....................................................................... 16 6.0 CLOSURE ..................................................................................................................................... 16 List of Tables Table 1. Approximate Locations and Depths of Explorations ............................................................................. 2 Table 2. Seismic Design Parameters ........................................................................................................................ 6 List of Figures Figure 1. Topographic and Location Map Figure 2. Site and Exploration Plan Figure 3. Excerpt from Geologic Map of the Tacoma 1:100,000-scale Quadrangle (2015) Figure 4. Liquefaction Susceptibility Map, King County, 2010 APPENDIX A Soil Classification Chart and Key to Test Data .................................................................................................. A-1 Log of Auger Borings B-1 through B-4 ..................................................................................................... A-2…A-5 MIGIZI GROUP, INC. PO Box 44840 PHONE (253) 537-9400 Tacoma, Washington 98448 FAX (253) 537-9401 June 15, 2023 Helix Design Group, Inc. 6021 12th St E, #201 Tacoma, WA 98424 Attention: Erik Prestegaard / Jeff Ryan Subject: Geotechnical Engineering Report Proposed Steel Lake Operations & Maintenance Facility 31330 28th Avenue South Federal Way, WA 98003 Parcel Nos. 0921049009, 0921049026, 0921049075, 0921049084, 0921049085, 0921049095, 0921049115, 0921049170, 0921049198, 0921049239, 0921049240, 0921049250, 0921049313, 0921049314, 0921049315 MGI Project Z0390 Dear Mr. Prestegaard and Mr. Ryan: Migizi Group, Inc. (MGI) is pleased to submit this report describing the results of our geotechnical engineering evaluation of the proposed operations and maintenance facility improvements to be located along 28th Ave S in Federal Way, WA. This report has been prepared for the exclusive use of Helix Design Group, Inc. and their consultants for specific application to this project, in accordance with generally accepted geotechnical engineering practice. 1.0 SITE AND PROJECT DESCRIPTION The project site is currently occupied by 12 residential parcels, and an additional three parcels which make up the existing City of Federal Way Operations and Maintenance facility in Federal Way, WA as shown on the enclosed Topographic and Location Map (Figure 1). The proposed facility will incorporate the parcels, creating a single 13.5-acre project area, and is located in a moderately dense, populated residential area of Federal Way just west of Interstate 5. It is our understanding that development plans involve significant site clearing and grading, and construction of a 20,000-sf operations building, a 41,250-sf vehicle and equipment maintenance facility, 25,700-sf covered equipment storage buildings, a vehicle wash and fueling station, and areas for both private and public vehicle parking. Page 1 of 1Ŝ Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 2 of 16 2.0 EXPLORATORY METHODS We explored surface and subsurface conditions across the project area on January 3 and May 17, 2023. Our exploration and evaluation program included the following elements: • Surface reconnaissance of the site, • Four auger boring explorations (designated B-1 to B-4), advanced across the proposed improvement area, • A review of published geologic and seismologic maps and literature. Table 1 (below) summarizes the approximate functional locations and termination depths of our subsurface explorations, and Figure 2 (attached) depicts their approximate relative locations. The following sections describe the procedure used for excavation of the borings. TABLE 1 APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Exploration Functional Location Termination Depth B-1 B-2 B-3 B-4 ±108ft E and ±90ft S of NW parcel corner, existing maintenance facility property ±153ft E and ±80ft S of NW parcel corner, back yard of 30922 28th Ave S ±72ft E and ±10ft S of NW parcel corner, front yard of 2808 S 308th Lane ±230ft E and ±65ft N of SW parcel corner, existing maintenance facility property 20ft 2in 20ft 5in 20ft 10in 20ft 3in The specific number and locations of our explorations were selected in relation to the existing site features, under the constraints of property access, underground utility conflicts, and consideration for planned locations of proposed structures. It should be realized that the explorations performed and utilized for this evaluation reveal subsurface conditions only at discrete locations across the project site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendations contained in this report to reflect the actual site conditions. 2.2 Auger Boring Procedures Our auger boring explorations, advanced on January 3 and May 17, 2023, were advanced through the soil with a hollow-stem auger using both truck- and track-mounted drill rigs operated by an independent drilling firm working under subcontract to MGI. A geologist from our firm continuously observed the borings, logged the subsurface conditions, and collected representative soil samples. All samples were stored in watertight containers and later transported to a laboratory for storage and further visual examination. After the borings were completed, the boreholes were backfilled with bentonite chips and the top of each hole was capped with hand-mixed concrete. Throughout the drilling operation, soil samples were obtained at intervals of 2½ feet by means of the Standard Penetration Test (SPT) per American Society for Testing and Materials (ASTM:D- Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 3 of 16 1586). This testing and sampling procedure consists of driving a standard 2-inch-diameter steel split-spoon sampler 18 inches into the soil with a 140-pound hammer free-falling 30 inches. The number of blows required to drive the sampler through each 6-inch interval is counted, and the total number of blows struck during the final 12 inches is recorded as the Standard Penetration Resistance, or “SPT blow count.” If a total of 50 blows are struck within any 6-inch interval, the driving is stopped, and the blow count is recorded as 50 blows for the actual penetration distance. The resulting Standard Penetration Resistance values indicate the relative density of granular soils and the relative consistency of cohesive soils. The enclosed boring logs (Appendix A) describe the vertical sequence of soils and materials encountered in our explorations, based primarily on our field classifications, and supported by our subsequent laboratory examination and testing. Where soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If any groundwater was encountered in the borehole, the approximate groundwater depth is depicted on the boring log. Groundwater depth estimates are typically based on the moisture content of soil samples, the wet height on the drilling rods, and the water level measured in the borehole after the auger has been extracted. The soils were classified visually in general accordance with the system described in Figure A-1, which includes a key to the exploration logs. Summary logs of our explorations are included as Figures A-2 and A-5. 3.0 SITE CONDITIONS The following sections present our observations, measurements, findings, and interpretations regarding surface, soil, groundwater, seismic and infiltration conditions, and liquefaction potential. 3.1 Surface Conditions As previously indicated, the approximately 13.5-acre project site is occupied by the existing Operations and Maintenance Facility and 12 additional residential parcels, in a dense, residential neighborhood just north of downtown Federal Way, in between 28th Ave S to the west and the Sound Transit and Interstate 5 easements to the east. The residential parcels are currently occupied, with the City in negotiations to acquire the properties for this project. The total project area is ±1,270 feet along both the proposed western and eastern property lines, ±385 feet along the southern property line, and ±570 feet along the northern property line. Topographically, these properties are all elevated along 28th Ave S at approximately 500 feet above sea level (asl) and gently falls towards the east-northeast. The eastern property lines lie at an average elevation of 470 feet asl, creating a fall of roughly 6½ percent across the properties. Across the entirety of the project area, significant areas of the residential parcels are grassy sod and topsoil with maintained landscaping for garden beds and small farm plots. In addition, there are a considerable number of both immature and mature deciduous and fir trees across the Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 4 of 16 properties. The existing maintenance facility has a minimal amount of landscaping at the western end of the property and is mostly paved for the vehicle motor pool and storage of equipment and materials. During both site reconnaissance visits of January 3 and May 17, 2023, no additional hydrologic features such as seeps, springs, or streams were observed on the isolated parcels that were accessible. 3.2 Soil Conditions All auger boring explorations across the proposed project area revealed relatively consistent subgrade conditions across the project area. Soils were found to consist of a thin surface mantle of topsoil, or asphalt and crushed rock top course in paved areas, underlain by several feet of softer, saturated, and mottled silty sand with gravel, with more dense and drier gray silty sand with gravel through the bottom of all explorations. As noted above, borings were all terminated at approximately 20 feet below ground surface (bgs). In all explorations, shallower soils were observed to be in a moist to saturated and loose and soft condition based on both visual observations and recorded blow counts during sampling. Deeper soils were observed to be in a moist condition and very dense and cemented. A small amount of perched groundwater was observed in explorations between 5 to 10 feet bgs, creating moist conditions in more shallow soils, with deeper soils, due to their cemented nature, were drier. The Federal Way area, and the larger Puget Sound region in general, have been glaciated several times over the last 2.4 million years. The most recent of these glacial events, the Vashon Stade of the Fraser Glaciation, receded from this region approximately 13,500 years ago. These glacial events have left thickened zones of very dense glacial till, a heterogeneous mixture of cemented silt, sand, and gravel after being overridden by the glaciers. Typically, glacial till is exposed at the surface across the Puget Sound region as elevated topographic locations. In the Geologic Map of the Tacoma 1:100,000-scale Quadrangle, Washington as prepared by Robert Logan at the Washington State Department of Natural Resources (WSDNR) (2015), the project site is mapped as containing Qgt, or Vashon glacial till. These soils are described as being dense, massive deposits of silt, sand, and gravel, with gravel varying in size up to very large boulders. Deposits are generally cemented and very dense, with low permeability and porosity. An excerpt of the map of the immediate project area can be found as Figure 3 (page 6). Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 5 of 16 Figure 3. Excerpt from Geologic Map of the Tacoma 1:100,000-scale Quadrangle (2015) The National Cooperative Soils Survey (NCSS) classifies onsite soils as those of the Alderwood gravelly sandy loam complex. The western halves of the properties are designated as AgB – Alderwood gravelly sandy loam, 0 to 8 percent slopes. The eastern halves of the properties down towards the Interstate 5 easement are classified as AgC – Alderwood gravelly sandy loam, 8 to 15 percent slopes. These soils are generally found to consist of very gravelly sandy loam down to 5 feet deep, and depth to restrictive features is approximately 20 to 39 inches. These soils generally have a very low capacity to transmit water vertically, and the depth to the water table is approximately 1.5 to 3 feet below ground surface. Our subsurface observations generally conform with the classifications prepared by both the WSDNR and NCSS observations. The enclosed exploration logs (Appendix A) provide a detailed description of the soil strata encountered in our subsurface explorations. 3.3 Groundwater Conditions At the time of our reconnaissance and subsurface explorations (January 3 and May 17, 2023), we encountered small amounts of perched groundwater in all four borings. In all explorations, depth to groundwater was at approximately 7.5 feet bgs, plus or minus 2.5 foot. Although explorations were drilled outside of what is considered the Western Washington wet season, we do not anticipate that groundwater levels will rise much higher than that which we observed, nor be a limiting factor in the proposed development. Groundwater levels will fluctuate with localized geology and precipitation. Approximate Project Site Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 6 of 16 3.4 Seismic Conditions The site is in the Puget Sound basin which has experienced several earthquakes. A detailed description of the regional seismicity is beyond the scope of this report; however, previous regional earthquakes can be split into two general categories 1) large earthquakes with a moment magnitude greater than 8.0 (MW > 8.0), and 2) modest size earthquakes with a moment magnitude generally less than 7.25 (MW < 7.25). In all cases the thickness of the soil between the bedrock and the ground surface can change (usually amplify) the seismically induced ground motions and therefore the inertial loads acting on surface structures. “Site Class” is a classification system used by the International Building Code (IBC) and ASCE 7-16 to provide some insight to the potential for ground motion amplification. The site class is based on the properties of the upper 200 feet of the soil and rock materials at the site. ASCE 7-16 Section 20.3.1.1 allows the seismic response spectra to be developed based on a Site Class D – Stiff Soil designation. Using the third-party graphical user interface tools made available by the USGS at https://seismicmaps.org, with inputs of the project location, Risk Category I/II/III, and Site Class D – Stiff Soil, the results provided in Table 2 (below) were obtained. TABLE 2 SEISMIC DESIGN PARAMETERS Parameter Value Basis Site Class D-Stiff Soil Site-specific data SS 1.321 seismicmaps.org Fa 1 seismicmaps.org SMS 1.321 = Fa · SS SDS 0.881 = 2/3 SMS S1 0.453 seismicmaps.org FV 1.847 B, C 2018 IBC SM1 0.837 B, C = FV · S1 (2018 IBC) SD1 0.558 B, C = 2/3 SM1 (2018 IBC) PGA 0.559 g seismicmaps.org PGAM 0.614 g seismicmaps.org T0 -- C Not applicable TS -- C Not applicable TL 6 sec. seismicmaps.org Notes: A. Use the value provided unless the simplified design procedure of ASCE 7 Section 12.14 is used. If this occurs, please contact our office for more information. B. Based on Table 11.4.2 of the ASCE 7-16 – an ASCE 7-16 Chapter 21 analysis has not been performed. C. More detailed seismic design criteria are available upon request. Please contact MGI’s office for more information. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 7 of 16 3.5 Liquefaction Potential Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by shear strains, as could result from an earthquake. Research has shown that saturated, loose, fine to medium sands with a fines (silt and clay) content of less than about 20 percent are most susceptible to liquefaction. Subsurface explorations performed within the confines of the project area did not encounter any saturated and loosely consolidated sandy soils, and we interpret the potential for seismically induced liquefaction to be very low within the subject property. This interpretation for the project site is also depicted in the 2010 Liquefaction Susceptibility Map of King County by Tetra Tech, Inc. as shown in Figure 4 (below). Figure 4. Seismic Soils and Liquefaction Susceptibility Risk Map, King County, 2010 3.6 Infiltration Conditions and Infiltration Rate As indicated in the Soil Conditions section of this report, the site is underlain by very dense cemented glacial till deposits originating from historic glacial activity. The uppermost 5 to 10 feet of the soil column is highly weathered and was observed in a medium dense and very saturated in situ condition. Beneath the saturated and medium dense weathered glacial till section, very Approximate project location Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 8 of 16 dense and drier unweathered glacial till soils were observed through the termination of all explorations. Glacial till soils are generally considered an impervious surface in most stormwater design manuals. As such, we do not believe that a deep infiltration design is feasible for this project, but shallow BMP’s such as pervious pavement and/or raingardens can likely be constructed, utilizing the shallow weathered horizon as the infiltration medium. At the time of site reconnaissance and exploration, MGI was not requested to conduct any infiltration testing of native soils. A long-term design infiltration rate for these shallow BMPs should be based on future infiltration testing of those soils at appropriate elevations. 4.0 CONCLUSIONS AND RECOMMENDATIONS It is our understanding that development plans involve significant site clearing and grading of the existing maintenance facility and residential parcels with construction of several new office and maintenance buildings for vehicle, materials, and equipment repair and storage. Buildings will be either wood or steel-framed and will be built at or near existing grade. New or redesigned asphalt parking for private and public vehicles may be installed around the planned buildings. We offer the following recommendations: • Feasibility: Based on our field explorations, research and evaluations, the proposed structures appear feasible from a geotechnical standpoint. • Foundation Options: Foundation elements for the proposed structures should be constructed on medium dense or denser undisturbed native soils. We anticipate that adequate bearing soil will be encountered within 3 to 4 feet below existing elevation across the proposed building area. Recommendations for foundation support are provided in Section 4.2. • Floor Options: Floor sections should bear on medium dense or denser native soils or on properly compacted structural fill that extends down to medium dense or denser native soil. We anticipate that adequate bearing soil will be encountered at relatively shallow depths (3 to 4 feet bgs) at the proposed building areas, and we do not foresee the need for a granular fill subbase. Recommendations for slab-on-grade floors are included in Section 4.3. • Infiltration Conditions: Based on our observations, we believe that full infiltration is infeasible for this project, but shallow BMP’s can likely be constructed utilizing the shallow weathered glacial till soil horizon as the infiltration medium. Such facilities should maintain an appropriate separation from unweathered glacial till soils and seasonally high groundwater. A long-term design infiltration rate should be based on onsite infiltration testing. • Pavement Sections: Native, in-situ soil conditions are amenable to the use of soil- supported pavements. We recommend a conventional pavement section comprising an asphalt concrete pavement over a crushed rock base course over a properly prepared (compacted) subgrade or a granular subbase, depending on subgrade conditions during pavement subgrade preparation. All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 9 of 16 during this proof-rolling operation should be over-excavated to a depth of 12 inches and replaced with a suitable structural fill material. • Geologic Hazards: During our site reconnaissance, advancement of subsurface explorations, and general evaluation of the proposed development, we did not observe any erosional, landslide, seismic, settlement, or other forms of geologic hazards within the subject property. Given this fact, we recommend that no buffers, setbacks, or other forms of site restraints be implemented to address these potential hazards. The following sections of this report present our specific geotechnical conclusions and recommendations concerning site preparation, spread footings, structural fill, slab-on-grade floors, drainage systems, and asphalt pavement. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard Plans cited herein refer to WSDOT publications M41-10, Standard Specifications for Road, Bridge, and Municipal Construction, and M21-01, Standard Plans for Road, Bridge, and Municipal Construction, respectively. 4.1 Site Preparation Preparation of the project site will most likely involve a significant amount of erosion control, grading, excavations, and subgrade compaction. Erosion Control: Before new construction begins, an appropriate erosion control system should be installed. This system should collect and filter all surface water runoff through silt fencing. We anticipate a system of berms and drainage ditches around construction areas will provide an adequate collection system. Silt fencing fabric should meet the requirements of WSDOT Standard Specification 9-33.2 Table 6. In addition, silt fencing should embed a minimum of 6 inches below existing grade. An erosion control system requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has shifted above ground surface should be replaced or repaired as soon as they are identified. Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or near-surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Based on our current understanding of the construction plans, surface, and subsurface conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff. Site Excavations: Based on our explorations, we expect deeper site excavations in native soils will predominantly encounter densely consolidated glacial till soils, consisting of silty sand with gravel. This soil group can be readily excavated utilizing standard excavation equipment, though special “ripper” teeth may be needed for more rapid excavation. Shallower excavations will encounter a mix of highly weathered moderately consolidated glacial soils which can be readily excavated using standard excavation equipment. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 10 of 16 Dewatering: A minor amount of groundwater seepage was encountered in all explorations across the site. The depth to groundwater was approximately 5 to 10 feet below existing grade. If groundwater is encountered, we anticipate that an internal system of ditches, sump holes, and pumps will be adequate to temporarily dewater shallow excavations. Temporary Cut Slopes: At this time, final designs and construction sequencing have not been completed. To facilitate project planning, we provide the following general comments regarding temporary slopes: x All temporary soil slopes associated with site cutting or excavations should be adequately inclined to prevent sloughing and collapse, x Temporary cut slopes in site soils should be no steeper than 2H:1V, due to the loose and unconsolidated nature of the native outwash gravels, and x Temporary slopes should conform to Washington Industrial Safety and Health Act (WISHA) regulations. These general guidelines are necessarily somewhat conservative (steeper temporary slopes may be possible). As the project progresses, temporary grading plans are developed, final site features are better defined, and a contractor is engaged, MGI may modify these general guidelines to allow steeper slopes. Subgrade Compaction: Exposed subgrades for the foundations of the planned structures should be compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed within a subgrade should be over-excavated and replaced with a suitable structural fill material. Site Filling: Our conclusions regarding the reuse of onsite soil and our comments regarding wet- weather filling are presented subsequently. Regardless of soil type, all fill should be placed and compacted according to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent (based on ASTM:D-1557). Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural fill: • Surficial Organic Soil and Organic-Rich Fill Soils: Where encountered, surficial organic soils like duff, topsoil, root-rich soil, and organic-rich fill soils are not suitable for use as structural fill under any circumstances due to high organic content. Consequently, this material can be used only for non-structural purposes, such as in landscaping areas. • Glacial Till Soils: Glacial till soils are the predominant soil group present beneath the project site. This material type will be the primary source of site produced structural fill. Due to the high relative fines content, this material type should be considered highly Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 11 of 16 moisture sensitive and will become increasingly difficult, if not impossible, to reuse as structural fill in wet weather conditions. As encountered on site, this material is typically at or below the optimum moisture content for the material type and no moisture conditioning should be anticipated prior to reuse. Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H:1V. For all soil types, the use of flatter slopes (such as 2½H:1V) would further reduce long-term erosion and facilitate revegetation. Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the top edge of all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as soon as feasible to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could be armored with quarry spalls or a geosynthetic erosion mat. 4.2 Spread Footings In our opinion, conventional spread footings will provide adequate support for the proposed modular structure if the subgrade is properly prepared. We offer the following comments and recommendations for spread footing design. Footing Depths and Widths: For frost and erosion protection, the bases of all exterior footings should bear at least 18 inches below adjacent outside grades, whereas the bases of interior footings need bear only 12 inches below the surrounding slab surface level. To reduce post- construction settlements, continuous (wall) and isolated (column) footings should be at least 16 and 24 inches wide, respectively. Bearing Subgrades: Footings should bear on medium dense or denser soils which have been stripped of surficial organic soils and vigorously surface compacted, or on properly compacted structural fill bearing which extend down to soils described above. We anticipate that adequate bearing soil will be encountered at approximately 3 to 4 feet below existing elevation across the proposed building area. In general, before footing concrete is placed, any localized zones of loose soils exposed across the footing subgrades should be compacted to a firm, unyielding condition, and any localized zones of soft, organic, or debris-laden soils should be over-excavated and replaced with suitable structural fill. Lateral Over excavations: Because foundation stresses are transferred outward as well as downward into the bearing soils, all structural fill placed under footings should extend horizontally outward from the edge of each footing. This horizontal distance should be equal to the depth of placed fill. Therefore, placed fill that extends 3 feet below the footing base should also extend 3 feet outward from the footing edges. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 12 of 16 Subgrade Observation: All footing subgrades should consist of firm, unyielding, soils, or structural fill materials that have been compacted to a density of at least 95 percent (based on ASTM:D-1557). Footings should never be cast atop loose, soft, or frozen soil, slough, debris, existing uncontrolled fill, or surfaces covered by standing water. Bearing Pressures: In our opinion, for static loading, footings that bear on dense glacial till soils can be designed for a maximum allowable soil bearing pressure of 2,500 psf. This value is conservative and may be increased for specific footings if we are consulted. A one-third increase in allowable soil bearing capacity may be used for short-term loads created by seismic or wind related activities. Footing Settlements: Assuming that structural fill soils are compacted to a medium dense or denser state, we estimate that total post-construction settlements of properly designed footings bearing on properly prepared subgrades will not exceed 1 inch under static conditions. Differential settlements for comparably loaded elements may approach one-half of the actual total settlement over horizontal distances of approximately 50 feet. Footing Backfill: To provide erosion protection and lateral load resistance, we recommend that all footing excavations be backfilled on both sides of the footings and stemwalls after the concrete has cured. Either imported structural fill or non-organic onsite soils can be used for this purpose, contingent on suitable moisture content at the time of placement. Regardless of soil type, all footing backfill soil should be compacted to a density of at least 90 percent (based on ASTM:D- 1557). Lateral Resistance: Footings that have been properly backfilled as recommended above will resist lateral movements by means of passive earth pressure and base friction. We recommend using an allowable passive earth pressure of 225 psf and an allowable base friction coefficient of 0.35 for site soils. 4.3 Structural Fill The term "structural fill" refers to any material placed under foundations, retaining walls, slab- on-grade floors, sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning structural fill are presented in the following paragraphs. Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock, well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit- run"), and miscellaneous mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing the parent materials, are also potentially useful as structural fill in certain applications. Utilizing recycled content may require approval from the King County Health Department. Soils used for structural fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches in diameter. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 13 of 16 Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a mechanical compactor. Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that structural fill used for various onsite applications be compacted to the following minimum densities: Fill Application Minimum Compaction Footing subgrade and bearing pad Foundation backfill Slab-on-grade floor subgrade and subbase Asphalt pavement base and subbase Asphalt pavement subgrade (upper 2 feet) Asphalt pavement subgrade (below 2 feet) 95 percent 90 percent 95 percent 95 percent 95 percent 90 percent Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this report. The condition of all subgrades should be observed by geotechnical personnel before filling or construction begins. Also, fill soil compaction should be verified by means of in-place density tests performed during fill placement so that adequacy of soil compaction efforts may be evaluated as earthwork progresses. Soil Moisture Considerations: The suitability of soils used for structural fill depends primarily on their grain-size distribution and moisture content when they are placed. As the "fines" content (that soil fraction passing the U.S. No. 200 Sieve) increases, soils become more sensitive to small changes in moisture content. Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm, unyielding condition when the moisture content is more than 2 percentage points above or below optimum. For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve. 4.4 Slab-On-Grade Floors In our opinion, soil-supported slab-on-grade floors can be used in the proposed structures if the subgrades are properly prepared. We offer the following comments and recommendations concerning slab-on-grade floors. Floor Subbase: Structural fill subbases do not appear to be needed under soil-supported slab-on- grade floors at the site. However, the final decision regarding the need for subbases should be based on actual subgrade conditions observed at the time of construction. If a subbase is needed, all subbase fill should be compacted to a density of at least 95 percent (based on ASTM:D-1557). All subgrades should be vigorously surface compacted to a medium dense or denser condition before slab construction begins. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 14 of 16 Capillary Break and Vapor Barrier: To retard the upward wicking of groundwater beneath the floor slab, we recommend that a free-draining capillary break be placed over the subgrade. Ideally, this capillary break would consist of a 6-inch-thick layer of pea gravel or other clean, uniform, and well-rounded gravel, such as “Gravel Backfill for Drains” per WSDOT Standard Specification 9-03.12(4), but clean angular gravel can be used if it adequately prevents capillary wicking. In addition, a layer of plastic sheeting (such as Crosstuff, Visqueen, or Moistop) should be placed over the capillary break to serve as a vapor barrier. During subsequent casting of the concrete slab, the contractor should exercise care to avoid puncturing this vapor barrier. 4.5 Drainage Systems In our opinion, the proposed structures should be provided with permanent drainage systems to reduce the risk of future moisture problems. We offer the following recommendations and comments for drainage design and construction purposes. Perimeter Drains: We recommend that the buildings be encircled with a perimeter drain system to collect seepage water. This drain should consist of a 6-inch-diameter perforated pipe within an envelope of pea gravel or washed rock, extending at least 6 inches on all sides of the pipe, and the gravel envelope should be wrapped with filter fabric to reduce the migration of fines from the surrounding soils. Ideally, the drain invert would be installed no more than 8 inches above the base of the perimeter footings. Discharge Considerations: If possible, all perimeter drains should discharge to a sewer system or other suitable location by gravity flow. Check valves should be installed along any drainpipes that discharge to a sewer system, to prevent sewage backflow into the drain system. Runoff Water: Roof-runoff and surface-runoff water should not discharge into the perimeter drain system. Instead, these sources should discharge into separate tightline pipes and be routed away from the building to a storm drain or other appropriate location. Grading and Capping: Final site grades should slope downward away from the buildings so that runoff water will flow by gravity to suitable collection points rather than ponding near the building. Ideally, the area surrounding the building would be capped with concrete, asphalt, or low-permeability (silty) soils to minimize or preclude surface-water infiltration. 4.6 Asphalt Pavement We offer the following comments and recommendations for asphalt pavement design and construction. Subgrade Preparation: Structural fill subbases do not appear to be needed under pavements at the site. However, the final decision regarding the need for subbases should be based on actual subgrade conditions observed at the time of construction. If a subbase is needed, all subbase fill should be compacted to a density of at least 95 percent (based on ASTM:D-1557). Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 15 of 16 All soil subgrades should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be over excavated to a minimum depth of 12 inches and replaced with a suitable structural fill material. All structural fill should be compacted according to our recommendations given in the Structural Fill section. Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 95 percent (based on ASTM D-1557), and all soils below 2 feet should be compacted to at least 90 percent. Pavement Materials: For the base course, we recommend using imported crushed rock, such as "Crushed Surfacing Top Course” per WSDOT Standard Specification 9-03.9(3). If a subbase course is needed, we recommend using imported, clean, well-graded sand and gravel such as “Ballast” or “Gravel Borrow” per WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively. Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete pavement over a crushed rock base course. We recommend using the following conventional pavement sections: Minimum Thickness Pavement Course Automobile Parking Areas Driveway Areas Areas subjected to Heavy Traffic Asphalt Concrete Pavement 2 inches 3 inches 4 inches Crushed Rock Base 4 inches 6 inches 8 inches Granular Fill Subbase (if needed) 8 inches 12 inches 16 inches Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an MGI representative be retained to observe the compaction of each course before any overlying layer is placed. For the subbase and pavement course, compaction is best observed by means of frequent density testing. For the base course, methodology observations and hand-probing are more appropriate than density testing. Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above- described pavement sections present our minimum recommendations for an average level of performance during a 20-year design life; therefore, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about 10 years. Thicker asphalt and/or thicker base and subbase courses would offer better long-term performance but would cost more initially; thinner courses would be more susceptible to “alligator” cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. Helix Design Group, Inc. – Steel Lake Operations & Maintenance Facility, Federal Way, WA June 15, 2023 Geotechnical Engineering Report Z0390 Migizi Group, Inc. Page 16 of 16 5.0 RECOMMENDED ADDITIONAL SERVICES Because the future performance and integrity of the structural elements will depend largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced geotechnical personnel should be considered an integral part of the construction process. Subsequently, we recommend that MGI be retained to provide the following post-report services: • Review all construction plans and specifications to verify that our design criteria presented in this report have been properly integrated into the design, • Prepare a letter summarizing all review comments (if required), • Check all completed subgrades for footings before concrete is poured to verify their bearing capacity, and • Prepare a post-construction letter summarizing all field observations, inspections, and test results (if required). 6.0 CLOSURE The conclusions and recommendations presented in this report are based, in part, on the explorations that we observed for this study; therefore, if variations in the subgrade conditions are observed at a later time, we may need to modify this report to reflect those changes. Also, because the future performance and integrity of the project elements depend largely on proper initial site preparation, drainage, and construction procedures, monitoring and testing by experienced geotechnical personnel should be considered an integral part of the construction process. MGI is available to provide geotechnical monitoring of soils throughout construction. We appreciate the opportunity to be of service on this project. If you have any questions regarding this report or any aspects of the project, please feel free to contact our office. Respectfully submitted, MIGIZI GROUP, INC. 06/15/23 Randall V. Conger-Best, L.G. James E. Brigham, P.E. Senior Staff Geologist Senior Principal Engineer APPROXIMATE SITE LOCATION P.O. Box 44840 Tacoma, WA 98448 Location Job Number Figure DateTitle 31330 28th Avenue South Federal Way, WA 98003 Topographic and Location Map 1 06/14/23 Z0390 APPENDIX A SOIL CLASSIFICATION CHART AND KEY TO TEST DATA LOG OF AUGER BORINGS CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY MIXTURES SILTS AND CLAYSCOARSE GRAINED SOILSMore than Half > #200 sieveLIQUID LIMIT LESS THAN 50 LIQUID LIMIT GREATER THAN 50 CLEAN GRAVELS WITH LITTLE OR NO FINES GRAVELS WITH OVER 15% FINES CLEAN SANDS WITH LITTLE OR NO FINES MORE THAN HALF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE MORE THAN HALF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE INORGANIC SILTS, MICACEOUS OR DIATOMACIOUS FINE SANDY OR SILTY SOILS, ELASTIC SILTS ORGANIC CLAYS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY OH INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS, OR CLAYEY SILTS WITH SLIGHT PLASTICITY CH SILTY GRAVELS, POORLY GRADED GRAVEL-SAND-SILT MIXTURES SANDS SILTS AND CLAYS )LJXUH$ INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS R-Value Sieve Analysis Swell Test Cyclic Triaxial Unconsolidated Undrained Triaxial Torvane Shear Unconfined Compression (Shear Strength, ksf) Wash Analysis (with % Passing No. 200 Sieve) Water Level at Time of Drilling Water Level after Drilling(with date measured) RV SA SW TC TX TV UC (1.2) WA (20) Modified California Split Spoon Pushed Shelby Tube Auger Cuttings Grab Sample Sample Attempt with No Recovery Chemical Analysis Consolidation Compaction Direct Shear Permeability Pocket Penetrometer CA CN CP DS PM PP PtHIGHLY ORGANIC SOILS TYPICAL NAMES GRAVELS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES MAJOR DIVISIONS PEAT AND OTHER HIGHLY ORGANIC SOILS WELL GRADED SANDS, GRAVELLY SANDS POORLY GRADED SANDS, GRAVELLY SANDS SILTY SANDS, POORLY GRADED SAND-SILT MIXTURES CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES SOIL CLASSIFICATION CHART AND KEY TO TEST DATA GW GP GM GC SW SP SM SC ML FINE GRAINED SOILSMore than Half < #200 sieveLGD A NNNN02 GINT US LAB.GPJ 11/4/05INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS CL OL MH SANDS WITH OVER 15% FINES Migizi Group, Inc. !"#$ "% "#" !&# $'"!(%# !#" !&# $'"!(%# !$'""#" !!(%# #" !&# $'"!(%# $'""#" !!(%# ) %*" +,-) ./#""+#$ 0"!/#""#!$ 12) 3452.64278)2+/24.0 4329: :#$3 0"#;/#$!<(=! > 4< "59< #!?#! !!:#"# @ 3'! 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reliminary Technical Information Report City of Federal Way Operations & Maintenance Facility 2200572.12 Appendix D Worksheets (to be provided with Final TIR) D-1.................... TIR Worksheet D-2.................... Operations and Maintenance Manual D-3.................... Bond Quantity Worksheet D-4.................... Stormwater Facility Summary