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Home My WebLink AboutRS_Drainage_TIR_190917_V1.pdf FINAL TECHNICAL INFORMATION REPORT FOR CANOPY CITY OF RENTON IN KING COUNTY, WASHINGTON Project Manager: Gary Sharnbroich, P.E. Prepared by: Ruby Mohammadi Approved by: Holli Heavrin, P.E. Date: April 2019 Core No.: 18054 04/26/2019 Core Design, Inc. WESTVIEW VILLAGE i Table of Contents SECTION 1: PROJECT OVERVIEW ..................................................................................................... 1 SECTION 2: CONDITIONS AND REQUIREMENTS SUMMARY ........................................................... 3 2.1 Core Requirements ............................................................................................................... 4 2.1.1 Core Requirement #1: Discharge at the Natural Location ............................................ 4 2.1.2 Core Requirement #2: Offsite Analysis .......................................................................... 4 2.1.3 Core Requirement #3: Flow Control .............................................................................. 4 2.1.4 Core Requirement #4: Conveyance System .................................................................. 4 2.1.5 Core Requirements #5: Erosion and Sediment Control ................................................. 4 2.1.6 Core Requirement #6: Maintenance and Operations ................................................... 4 2.1.7 Core Requirement #7: Financial Guarantees and Liability ............................................ 4 2.1.8 Core Requirement #8: Water Quality ............................................................................ 4 2.1.9 Core Requirement #9: Flow Control BMPs .................................................................... 4 2.2 Special Requirements ............................................................................................................ 5 2.2.1 Special Requirement #1: Other adopted Area-Specific requirements .............................. 5 2.2.1.1 Master Drainage Plans (MDPs) ....................................................................................... 5 2.2.1.2 Basin Plans (BPs) ............................................................................................................. 5 2.2.1.3 Salmon Conservation Plans (SCPs) .................................................................................. 5 2.2.1.4 Lake Management Plans ................................................................................................. 5 2.2.1.5 Hazard Mitigation Plan ................................................................................................... 5 2.2.1.6 Shared Facility Drainage Plans (SFDPs) ........................................................................... 5 2.2.2 Special Requirement #2: Flood Hazard Delineation .......................................................... 5 2.2.3 Special Requirement #3: Flood Protection Facilities ......................................................... 5 2.2.4 Special Requirement #4: Source Control ........................................................................... 5 2.2.5 Special Requirement #5: Oil Control .................................................................................. 5 2.2.6 Special Requirement #6: Aquifer Protection Area (APA) ................................................... 5 SECTION 3: OFFSITE ANALYSIS ......................................................................................................... 6 TASK 1 Study Area Definition and Maps ..................................................................................... 6 TASK 2 Resource Review ............................................................................................................. 6 TASK 3 Field Investigation ........................................................................................................... 6 Core Design, Inc. CANOPY ii TASK 4 Drainage System Description and Problem Description ................................................. 7 SECTION 4: FLOW CONTROL AND WATER QUALITY DESIGN .......................................................... 8 4.1 Performance Standards ........................................................................................................ 8 4.2 Design Parameters .............................................................................................................. 11 4.3 Basin Modeling .................................................................................................................... 11 4.3.1 Existing Conditions ....................................................................................................... 11 4.3.2 Developed Conditions .................................................................................................. 13 4.4 BMP Requirements ............................................................................................................ 16 4.5 Detention Modeling ........................................................................................................... 18 4.6 Water Quality Calculations ................................................................................................. 18 SECTION 5: CONVEYANCE SYSTEM ANALYSIS AND DESIGN .......................................................... 21 SECTION 6: SPECIAL REPORTS AND STUDIES ................................................................................. 22 SECTION 7: OTHER PERMITS .......................................................................................................... 23 SECTION 8: ESC ANALYSIS AND DESIGN ........................................................................................ 24 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ...................... 25 9.1 Bond Quantities .................................................................................................................. 25 9.2 Facility Summaries .............................................................................................................. 25 9.3 Declaration of Covenant ..................................................................................................... 25 SECTION 10: OPERATIONS AND MAINTENANCE ........................................................................... 26 Appendix A – Parcel & Basin Information King County Parcel Reports Appendix B – Resource Review & Off-site Analysis Documentation FEMA Map (53033C0664 F) City Flood Hazard Areas Map City Stream and Wetland Map City Zoning Map City Landslide Hazard Areas Map Appendix C – Special Reports and Studies Geotechnical report by Terra Associates, Inc. Appendix D – Basin and Detention Modeling Documentation MGS Flood Full Report Core Design, Inc. 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Canopy Page 1 SECTION 1: PROJECT OVERVIEW The Canopy project site consists of five parcels with a total area of 10.06 acres (438102 SF per survey), located east of the Lincoln Ave NE and north of NE 40th ST in the City of Renton. The site is bordered by single family residentials to the north, east and south. The south property line is shared with NE 40th ST and the east property line is shared with Lincoln Ave NE. the project site is zoned R-8 and will be developed in accordance with the applicable City of Renton code. See Figure 1.1 at the end of this section for a vicinity map. The King County tax parcel ID numbers for the parcels involved is included in Table 1.1 below. (Refer to the King County parcel reports included in Appendix A). Table 1.1 King County Parcel ID KC Parcel # Parcel Area (SF) 3345700015 218,091 3345700016 40,430 3345700017 75,755 3345700018 75,698 3345700020 29,562 The project site is currently comprised of three vacant and unimproved parcels and two properties each containing single family residences and associated structures. Trees and underbrush cover most of the site. See the existing conditions exhibit at the end of this section. The parcels generally slope from east to west. The proposed development of the property will include the clearing and grading of the site for construction of a new 56 single family development with associated roadway, utilities, open space, stormwater detention and water quality facilities. The project will require frontage half street improvements along Lincoln Ave NE and NE 40th Street. Lincoln Ave NE is classified as a collector arterial street which requires a travel paved width of 30 feet, 8-feet wide street parking lane on both sides, 0.5-feet wide curbs, 8-feet wide planters, 8-feet wide sidewalk, 1 to 2 feet wide clear width back of sidewalk, stormwater improvements and street lighting. NE 40th Street is classified as a residential street with existing ROW width of approximately 60 feet which requires paved travel roadway width of 26 feet or paved width to match existing paved width along the corridor (the large number), 0.5 feet wide curbs, 8-feet wide landscaped planters, 5-feet wide sidewalks, drainage improvements, and streetlights. The project will be designed using the guidelines and requirements established in the 2017 Renton Surface Water Design Manual (RSWDM). The project will be adding more than 7,000 square feet of new impervious area, so the project falls under Full Drainage Review and Conservation Flow Control (Level 2). Water quality is required since the project will add more than 5,000 sf of pollution generating impervious surface (PGIS) that is not fully dispersed. The project is required to provide basic water quality per the City of Renton. The drainage analysis for detention sizing was modeled using MGS Flood, an approved continuous modeling software. The water quality Core Design, Inc. Canopy Page 2 facility sizing calculations are based on the MGS Flood modeling of the site. Refer to section 4 of this report for more information. Figure 1.1 Vicinity Map Core Design, Inc. Canopy Page 3 SECTION 2: CONDITIONS AND REQUIREMENTS SUMMARY The proposed project is classified as requiring “Full Drainage Review” Per the figure 1.1.2.A of the 2017 City of Renton Surface water Design Manual (RSWDM). Therefore, all nine Core Requirements and 6 Special Requirements will be addressed per section 1.1 of the 2017 RSWDM. Core Design, Inc. Canopy Page 4 2.1 Core Requirements 2.1.1 Core Requirement #1: Discharge at the Natural Location This project will match the natural discharge location towards Lincoln Ave NE to the north. 2.1.2 Core Requirement #2: Offsite Analysis This core requirement is addressed in Section 3 of this report. 2.1.3 Core Requirement #3: Flow Control The project will meet Conservation Flow Control (Level 2). This requires that the developed condition discharge durations match the existing condition durations from 50% of the 2-year to the 50-year storm events and that the developed 2-year and 10-year peak discharge rates do not exceed the existing 2-year and 10-year peak discharge rates, respectively. Refer to section 4 of this report for a discussion and calculations. 2.1.4 Core Requirement #4: Conveyance System See Section 5 of this report. 2.1.5 Core Requirements #5: Erosion and Sediment Control The proposed erosion and sedimentation control BMP’s have been designed to meet the requirements and design standards in Appendix D of the 2017 RSWDM. See Section 8 of this report. 2.1.6 Core Requirement #6: Maintenance and Operations See section 10 of this report. 2.1.7 Core Requirement #7: Financial Guarantees and Liability A bond quantities worksheet is provided in section 9 of this report. 2.1.8 Core Requirement #8: Water Quality The project is required to meet Basic water quality standards in the 2017 RSWDM. See section 4 of this report for further discussion. 2.1.9 Core Requirement #9: Flow Control BMPs The project will implement flow control BMPs to mitigate the impact of storm and surface water runoff from development. Refer to section 4.4 of this report for a discussion of the applicable BMPs. Core Design, Inc. Canopy Page 5 2.2 Special Requirements 2.2.1 Special Requirement #1: Other adopted Area-Specific requirements 2.2.1.1 Master Drainage Plans (MDPs) Not applicable 2.2.1.2 Basin Plans (BPs) Not applicable 2.2.1.3 Salmon Conservation Plans (SCPs) Not applicable 2.2.1.4 Lake Management Plans Not applicable 2.2.1.5 Hazard Mitigation Plan Not applicable 2.2.1.6 Shared Facility Drainage Plans (SFDPs) Not applicable 2.2.2 Special Requirement #2: Flood Hazard Delineation The project is not within a flood hazard area as described in RMC 4-3-050. Refer to Appendix B of this report for the applicable FIRM map, the City of Renton Flood Hazard Areas Map and site location. 2.2.3 Special Requirement #3: Flood Protection Facilities The project is not within a flood hazard area and will not be reliant on flood protection facilities. Refer to Appendix B of this report for the applicable FIRM map, the City of Renton Flood Hazard Areas Map and site location. 2.2.4 Special Requirement #4: Source Control The proposed project is a single-family residential development and source control is not applicable. 2.2.5 Special Requirement #5: Oil Control The project is not a commercial development or high use site as defined in the 2017 RSDWM. Therefore, oil control is not applicable to the project. 2.2.6 Special Requirement #6: Aquifer Protection Area (APA) The project is not within an Aquifer Protection Areas Zones as defined in the Reference 15-B of the 2017 RSDWM. Therefore, Aquifer Protection Area is not applicable to the project. Core Design, Inc. Canopy Page 6 SECTION 3: OFFSITE ANALYSIS TASK 1 Study Area Definition and Maps The proposed project contains parcel numbers 3345700015, 3345700016, 3345700017, 3345700018 and 3345700020. TASK 2 Resource Review Basin Reconnaissance Summary Reports No Basin Reconnaissance Summary Reports appear to be available for the area that is within a quarter mile of this project site. FEMA Maps A FIRM map dated May 16, 1995 number 53033C0664 F was reviewed. The developable site is not located within a floodplain as it is covered by “Zone X – Outside of 500-year floodplain”. The FEMA Map is included in Appendix B. Sensitive Areas Folio The city of Renton Critical Areas Maps was reviewed to confirm whether or not the project site is located within a wetland, stream, seismic, landslide, or erosion hazard area (Critical Area Maps is included in Appendix B). Downstream Drainage Complaints Drainage complaints were researched within a quarter mile of the project site. Based on King County iMap Drainage Complaints Map, only one of the complaints are located downstream of the project site which have been closed in 2017. See Drainage Complaint Exhibit in Appendix B, for location of nearby drainage complaints. TASK 3 Field Investigation A field investigation was completed on May 22, 2018. Tributary Area The existing grade slopes moderately to steeply from the east to the west towards Lincoln Ave NE. On the northeast corner of the site there is a stream which flows to northwest through out of the site. Just off the southeast corner of the site, there is a stream running to southwest. Upstream Tributary Analysis The project site does have significant upstream tributary area. Drainage from the forested areas east of the project site runs on to the site. Core Design, Inc. Canopy Page 7 TASK 4 Drainage System Description and Problem Description A level one downstream analysis was performed during the field inspection. Stormwater onsite flows from the east of the property to the west towards Lincoln Ave NE. The site is located in the East Lake Washington-Bellevue South Drainage Basin. For the purpose of this report, onsite flows will be classified as north and south. North: As mentioned, on the northeast corner of the site there is a stream running to northwest through out of the site. Half of the northeast parcel stormwater flows to this stream. Remaining half north of the site flows from east to west toward the wetland area on northwest side of the site. All stormwater runoff reaching the wetland eventually drains to the depression and exits the site at the west property line in the northwest corner of the site. The stormwater flows east of the Lincoln Ave NE for approximately 250 feet length and combine with the stream on the intersection of Lincoln Ave NE and NE 43rd St. The stream traveling underneath Lincoln Ave NE to west and redirecting to west on south side of the NE 43rd St. South: Stormwater runoff from east to west and reaches to the wetland on west side of the site. All stormwater runoff reaching the wetland eventually drains to the existing type 2 manhole. Based on the city of Renton GIS Map an 18” pipe with 81 feet length, convey flows to the type 2 manhole on the west side of the Lincoln Ave NE. Then a 24” pipe with 14feet length, convey flows to the stream on west. The stream flows to northwest and north toward NE 43rd St. Once the stormwater is within the south side of NE 43rd St in the stream, the stormwater conveys to west for approximately 250 feet before entering a culvert that conveys stormwater under the NE 43rd St to north into a stream. The stormwater continues north on east side of Lake WA Blvd NE for approximately 370 feet. The stormwater conveys to a culvert under the NE 44th St to north into a stream that the flow continues to north for approximately 360 feet. A 66” pipe collects the stormwater from the stream and conveys northwest and discharges to Lake Washington. At this point the downstream drainage course is around a quarter mile downstream from the project site. Refer to the downstream exhibit at the end of this section. King County Drainage Complaint Exhibit Date: 5/24/2018 Notes: ±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 Search Results: King County Parcels Override 1 Parcels Drainage complaints 4,514752Downstream ExhibitThis map is a user generated static output from an Internet mapping site and is forreference only. Data layers that appear on this map may or may not be accurate,current, or otherwise reliable.WGS_1984_Web_Mercator_Auxiliary_SphereNotesNone5/25/2018Legend512256THIS MAP IS NOT TO BE USED FOR NAVIGATIONFeet512Information Technology - GIS0RentonMapSupport@Rentonwa.govCity and County BoundaryParcelsStreams (Classified)Type SType FType NpType Ns5' Primary5' IntermediateNetwork StructuresInletManholeUtility VaultUnknown StructureControl StructurePump StationDischarge PointStormwater MainCulvertOpen DrainsFacility OutlinePrivate Network StructuresInletManholeUtility VaultUnknown StructurePrivate Control StructurePrivate Discharge PointPrivate Water QualityPrivate Detention FacilitiesPondTankVaultWetland Core Design, Inc. Canopy Page 8 SECTION 4: FLOW CONTROL AND WATER QUALITY DESIGN 4.1 Performance Standards All stormwater facilities will be designed using the guidelines and requirements established in the 2017 Renton Surface Water Design Manual (RSWDM). The project consists of ROW frontage improvements in Lincoln Ave NE, NE 40th ST and the onsite development. As discussed in Section 3 of this report the ROW improvements and onsite work are within the same drainage basin. The performance standards for the ROW Improvements and onsite development are discussed below. Soils: Geotechnical Report Summary The onsite soils were investigated by Terra Associates, Inc. The soil conditions consist of 2 to 24 inches of topsoil overlaying medium dense to dense sandy silt and silty sand with varying gravel content (weathered till) overlaying dense sandy silt, silt with sand, and silty sand with varying gravel content (glacial till). Ground water was encountered in seven of the nine test pits at depth ranging from one and one-half to eight feet. The site is underlain by relatively impermeable glacial till soils and exhibited shallow perched groundwater seepage. Therefore, the site would not be suitable for support infiltration facilities and it is recommended that the development stormwater be routed to a conventional storm system for disposal. Refer to Appendix C for the full geotechnical report. Flow Control: Conservation Flow Control Standard The project is required to provide the Conservation Flow Control Standard, which requires maintaining the durations of high flows at their pre-development levels for all flows greater than one-half of the 2- year peak flow through the 50-year peak flow. The pre-development peak flow rates for the 2-year and 10-year runoff events must also be maintained under this requirement. Onsite Flow Control A detention facility in combination with BMPS are proposed for all target surfaces on site to meet the conservation flow control standard. The impervious areas include the new proposed roadways, driveways, walkways and roof. An area summary table of impervious and pervious areas, along with corresponding MGS Flood hydrologic analysis results are included in the following pages. The full MGS Flood Report is included in Appendix D of this report. Offsite Flow Control BMPs are proposed to mitigate a portion of the target surfaces. The remaining target areas will bypass the vault due to the existing topography. The onsite detention facility will over detain the onsite areas to meet the conservation flow control standard. Water Quality: Basic Water Quality The proposed project is required to meet Basic water quality requirements Per the figure 6.1.A of the 2017 City of Renton Surface water Design Manual (RSWDM). Core Design, Inc. Canopy Page 9 Core Design, Inc. Canopy Page 10 The Basic Water Quality Menu includes the following pollutant removal target: • Basis: Total Suspended Solids (TSS) Removal= 80% The project proposes to use sediment storage under the live storage in the detention facility. These treatment facilities will provide all the required pollutant removal targets. Refer to section 4.5 of this report for the water quality calculations, discussion, and proposed facility. Core Design, Inc. Canopy Page 11 4.2 Design Parameters Hydrologic Modeling The project proposes to use MGS Flood and approved continuous modeling program in order to model the project and flow control facilities. Refer to Appendix C for a full MGS Flood Report. 4.3 Basin Modeling 4.3.1 Existing Conditions Existing Onsite Basin The project site is located within the City of Renton and is approximately 10.06 acres in size, consisting of 5 parcels. The parcels generally slope towards the east to west. The project site is currently comprised of three vacant and unimproved parcels and two properties each containing single family residences and associated structures. Trees and underbrush cover most of the site. The project proposes to demolish the existing structures and construct a single-family development consisting of 56 units. Historic site conditions are assumed for all existing areas per Section 1.2.3.1 of the 2017 RSWDM (page 1-41). ONSITE BASIN Total Area = 8.39 acres GROUND COVER AREA(acres) Till Forest 7.70 Till Forest (Upstream) 0.69 Existing Offsite Basin The offsite project area consists of approximately 0.91 acres of Right-of-Way (ROW) along Lincoln Ave NE and NE 40th ST. The ROW work will consist of frontage improvements and trenching for utility connections. Historic site conditions are assumed for all existing areas per Section 1.2.3.1 of the 2017 RSWDM (page 1- 41). See the following area tables used to create the pre-developed peak flows. An existing conditions exhibit is provided at the end of this section. OFFSITE BASIN Total Area = 0.87 acres GROUND COVER AREA(acres) Till Forest 0.37 Till Forest (Bypass) 0.27 Till Forest (Addition) 0.23 Core Design, Inc. Canopy Page 12 Figure 4-1: Existing Conditions Basin Exhibit Core Design, Inc. Canopy Page 13 4.3.2 Developed Conditions Developed Onsite Basin The developed site will consist of 56 single family development with associated roadway, utility improvements and stormwater facilities. The project proposes to implement BMPs onsite in order to meet core requirement #9 and reduce stormwater flows. The full MGS Flood report is located in Appendix D. Onsite Basin: The developed site will consist of 56 single family development with associated roadway, utility improvements and stormwater facilities. The impervious area per lot was determined using the criteria in the 2017 RSWDM page 3-24. The impervious area will either be 4,000 square feet or the maximum impervious area permitted by code, whichever is less. The maximum impervious surface allowed in the urban residential, R-8, zone in the City of Renton, is 65%. Impervious coverage also includes frontage improvements along Lincoln Ave NE and NE 40th St (ROW Basin), and the access tracts. Due to the existing topography a portion site cannot gravity drain to the proposed detention vaults and will be maintain the natural drainage path (to wetland ‘B’). ONSITE BASIN (Tributary to Vaults) Total Area = 7.70 acres GROUND COVER AREA (acres) Till Forest 0.60 Till Grass 3.48 Impervious 3.62 ROW Basin: Due to existing topography, a portion of the frontage improvements along Lincoln Ave NE could not be collected and conveyed back on-site. Therefore, an impervious area equal to the unmitigated area of Lincoln Ave NE upstream of the site, will be collected and treated in lieu of the bypass area. Refer to the following table for a breakdown of the tributary ROW area. OFFSITE BASIN (Tributary to Vaults) Total Area = 0.37 acres GROUND COVER AREA (acres) Till Grass 0.07 Impervious 0.30 OFFSITE ADDITION (Tributary to Vaults) Total Area = 0.23 acres GROUND COVER AREA (acres) Till Grass 0.01 Impervious 0.22 Core Design, Inc. Canopy Page 14 OFFSITE BYPASS (Tributary to Downstream Basin within ¼ mile) Total Area = 0.28acres GROUND COVER AREA (acres) Till Grass 0.04 Impervious 0.24 Upstream Basin: Due to the existing topography of the area the lots to the east of the project disperse runoff towards the project. The upstream runoff will be collected and tight-lined to the proposed detention facilities. Refer to the upstream basin areas in the table below. UPSTREAM BASIN (Tributary to Vaults) Total Area = 0.68 acres GROUND COVER AREA (acres) Till Forest 0.68 Core Design, Inc. Canopy Page 15 Figure 4-2: Developed Conditions Exhibit Core Design, Inc. Canopy Page 16 4.4 BMP Requirements Flow control BMPs are proposed for the project per Core Requirement #9. The project is greater than 22,000 sf therefore, BMPs as specified in Section 1.2.9.2.2 of the 2016 RSWDM are required. The following are responses to the BMP requirements for Large Lot BMPs. 1) The feasibility and applicability of full dispersion as detailed in Appendix C, Section C.2.1 must be evaluated for all target impervious surfaces. If feasible and applicable for any such surface, then full dispersion must be applied to that surface and implemented as part of the proposed project. Typically, full dispersion will be applicable only on the largest sites/lots where there may be enough forest area available within a threshold discharge area to meet the 15% ratio of fully dispersed impervious area to native vegetated surface. Response: The applicable flowpath segments are generally located upstream of the target impervious surfaces onsite, Therefore, full dispersion is not feasible due to site constraints that do not allow for 100’ of native vegetative flow path. 2) Where full dispersion of target impervious roof areas is not feasible or applicable, or will cause flooding or erosion impacts, the feasibility and applicability of full infiltration of roof runoff must be evaluated in accordance with Appendix C, Section C.2.2, or Section 5.2, whichever is applicable based on the type of project. If feasible and applicable, full infiltration of roof runoff must be implemented as part of the proposed project. Response: Per section 4.8 of the Geotech Report, the subsurface conditions are not suitable for infiltration facilities. Therefore, full infiltration of roof runoff is not feasible. 3) All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list. Use of a given BMP is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. The BMPs listed below may be located anywhere on the site/lot subject to the limitations and design specifications for each BMP. These BMPs must be implemented as part of the proposed project. Response: Per section 4.8 of the Geotech Report, the subsurface conditions are not suitable for infiltration facilities. Therefore, full infiltration, limited infiltration and permeable pavement are not feasible. 4) All target impervious surfaces not mitigated by Requirements 1,2 and 3 above, must be mitigated to the maximum extent feasible using the Basic Dispersion BMP described below. Use of Basic Dispersion is subject to evaluation of its feasibility and applicability as detailed in Appendix C. Feasible BMPs are required to be implemented. Basic Dispersion BMPs may be located anywhere on the site/lot subject the limitations and design specifications cited in Appendix C. The BMP must be implemented as part of the proposed project. Response: Most of the areas that could be used for the “vegetated flowpath segment” are not located between potential dispersion devices and any downstream impervious surface or drainage feature. Therefore, this BMP is infeasible for the project site. 5) BMPs must be implemented, at minimum, for impervious area amounts defined as follows. • For projects that will result in an impervious surface coverage on the buildable portion of the site/lot of less than 45%, flow control BMPs must be applied to 50% of target impervious surfaces. Core Design, Inc. Canopy Page 17 • For projects that will result in an impervious surface coverage 45-65% on the buildable portion of the site/lot, flow control BMPs must be applied to 50% of target impervious surfaces reduced by 1.5% for each 1% of impervious surface coverage above 45% (e.g. impervious coverage of 55% results in a requirement of FCBMPs applied to 35% of target impervious surfaces). • For projects that will result in an impervious surface coverage greater than 65% on the buildable portion of the site/lot, flow control BMPs must be applied to 20% of the target impervious surfaces or to an impervious area equal to at least 10% of the site/lot, whichever is less. The buildable portion of the site/lot is the total area of the site/lot minus any critical areas and minus 200 ft. buffer areas from a steep slope hazard, landslide hazard area, or erosion hazard area. If these minimum areas are not mitigated using feasible BMPs from Requirements 1, 2, 3, and 4 above, either a fee in lieu of the required minimum BMPs must be paid (requires that King County Water and Land Resources Division has established a program for determining and utilizing the fees for stormwater focused retrofit projects) OR one or more BMPs from the following list are required to be implemented to achieve compliance. These BMPs must be implemented as part of the proposed project. Response: Reduced Impervious Surface Credit (Section C.2.9) has been evaluated for the project site. This project cannot use wheel strip driveways (Section C.2.9.3) due to the proposed parking layout, cannot implement a minimum disturbance foundation (Section C.2.9.4) due to the building type, and open grid decking over pervious surface (Section C.2.9.5) is not applicable. Additionally, the proposed improvements to the project create more than the threshold of 4,000 square feet or 4% of the total site area (whichever is greater) in impervious surface (Section C.2.9.2.2). Therefore, minimum design requirement #1 (specified in Section C.2.9.1) cannot be met; hence, this BMP cannot be claimed for the proposed site improvements. Native Growth Retention Credit (Section C.2.10) has been evaluated for the project site. Any potential area of target impervious surface to be credited as mitigated by this BMP must be directed to vegetated pervious surfaces on the site or discharged through a perforated pipe connection in accordance with Section C.2.11. It is not possible to direct stormwater runoff from the potential target impervious surfaces to vegetated pervious surfaces due to the elevation difference between the applicable areas. Therefore, minimum design requirement #4.b (specified in Section C.2.10.1) cannot be met; hence, this BMP cannot be claimed for the proposed site improvements. 6) The soil moisture holding capacity of new pervious surfaces (target pervious surfaces) must be protected in accordance with the soil amendment BMP as detailed in Appendix C, Section C.2.13. Response: The project will retain a portion of the native vegetation and forest near the northeast and southwest corner and east side of the property. In addition, all landscaping will provide compost amended soils per Reference 11-C to Satisfy the requirements (Notes will be included on the final landscape plans). 7) Any proposed connection of roof downspouts to the drainage system must be via a perforated pipe connection as detailed in Appendix C, Section C.2.11. Response: All proposed roof downspout connections will be shown as perforated pipe connections per Figure C.2.11.A of RSWDM. Core Design, Inc. Canopy Page 18 4.5 Detention Modeling There is one proposed detention facility that will be broken into two facilities due to site and utility constraints. The facilities will be hydraulically connected with one control structure downstream. Refer to the developed conditions exhibit above for a layout of the facility. Due to existence of ground water onsite the detention facility will be lined and therefore, stormwater will not be infiltrated. See Appendix D for the full MGS Flood Report. 4.6 Water Quality Calculations Onsite Water Quality The project proposes to use sediment and dead storage underneath the live storage in the detention facility (Vault 2). The treatment facility will provide the required pollutant removal target or 80% Total Suspended Solids. The required sediment volume using a basic wetpond was calculated using the 2017 Renton Surface Water Design Manual (RSWDM) Section 6.4.1.1. Wetvault (Basic) The 6-month, 24-hour precipitation amount is assumed to be 72 percent of the 2-year, 24-hour amount per Section 6.2.1. The 2-year 24-hour precipitation for the project site is 2.0 inches. Therefore, the 6- month 24-hour precipitation is 1.44 inches. A copy of the RSWDM isopluvial map, Figure 3.2.1.A is located at the end of this section. Step 1: Average Weighted Curve Number 𝐶𝐶𝐶𝐶=�𝐴𝐴𝐴𝐴× 98 +𝐴𝐴𝐴𝐴𝐴𝐴× 70 +𝐴𝐴𝐴𝐴𝐴𝐴× 86𝐴𝐴𝐴𝐴� Where: CN = Average Weighted Curve Number (Table 6.4.1.1.A) Area Impervious (CN= 98) Ai = Area Impervious (3.62 Onsite+0.53 Offsite= 4.15 acres) Area Till Forest (CN = 70) Atf = Total contributing site area (0.6 Onsite+0.68 Upstream= 1.28 acres) Area Till Grass (CN = 86) Atg = Total contributing site area (3.48 Onsite+0.08 Offsite= 3.56 acres) CN = 89.3 Step 2: Maximum Natural Detention (S) 𝑆𝑆=�1000𝐶𝐶𝐶𝐶�−10 S = 1.20 Step 3: Runoff Depth (Qd) Core Design, Inc. Canopy Page 19 𝑄𝑄𝑑𝑑=(𝑃𝑃−0.2𝑆𝑆)2(𝑃𝑃+0.8𝑆𝑆) Where: Qd = runoff depth in inches over the area P = precipitation depth in inches over the area S = potential maximum natural detention, in inches over the area due to infiltration, storage, etc. Qd = 0.6 Step 4: Wetpool Design Volume 𝑉𝑉𝑉𝑉𝑉𝑉𝑟𝑟𝑟𝑟𝑟𝑟=3,630 × 𝑄𝑄𝑑𝑑× 𝐴𝐴𝐴𝐴 Where: Qd = runoff depth in inches over the area At = Total contributing site area (8.81 acres) Volreq= 19,198 cf Using the equation above and the results from the previous steps, the required minimum wetvault volume, Volreq is 19,540 cubic feet (with 10% FS=22,472 cf). The provided wetvault volume is 22,560 cubic feet, with a dead storage depth of 4.7 feet. Core Design, Inc. Canopy Page 20 Core Design, Inc. Canopy Page 21 SECTION 5: CONVEYANCE SYSTEM ANALYSIS AND DESIGN * This Section will be provided in Final Design. Core Design, Inc. Canopy Page 22 SECTION 6: SPECIAL REPORTS AND STUDIES  Geotechnical Engineering Report (included in Appendix C) Prepared for: Blue Fern Development, LLC Prepared by: Carolyn S. Decker, P.E Dated: April 20, 2018 Terra Associates, Inc. 12220 113th Ave NE Ste. 130 Kirkland, WA 98034 Core Design, Inc. Canopy Page 23 SECTION 7: OTHER PERMITS  Right of Way Use Permit  Building Permit  NPDES Permit  Separate building permits for any retaining wall higher than 4’, Utility Connections, Detention Vaults, Pedestrian pathway stairs Core Design, Inc. Canopy Page 24 SECTION 8: ESC ANALYSIS AND DESIGN * This Section will be provided in Final Design. Core Design, Inc. Canopy Page 25 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 9.1 Bond Quantities A Site Improvement Bond Quantity Worksheet is included at the end of this section. 9.2 Facility Summaries Not applicable. 9.3 Declaration of Covenant A Declaration of Covenant is required to be submitted and approved by City Staff before permit issuance. After the stormwater system has been constructed, as-built, inspected, and accepted, a signed and notarized document will need recorded with the City and supplied to City Staff for reference. Core Design, Inc. Canopy Page 26 SECTION 10: OPERATIONS AND MAINTENANCE * This Section will be provided in Final Design. Appendix A Parcel & Basin Information Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department of Assessments 500 Fourth Avenue, Suite ADM- AS-0708, Seattle, WA 98104 Office Hours: Mon - Fri 8:30 a.m. to 4:30 p.m. TEL: 206- 296-7300 FAX: 206- 296-5107 TTY: 206- 296-7888 Send us mail ADVERTISEMENT New Search Property Tax Bill Map This Property Glossary of Terms Area Report Property Detail PARCEL Parcel Number 334570-0015 Name GOODWIN DC LLC Site Address Legal HILLMANS LK WN GARDEN OF EDEN # 7 LOT 3 LESS S 75 FT OF W 211 FT TGW W 50 FT OF TR 4 & POR OF S 135 FT OF TR 4 LY E OF SD W 50 FT ALL OF TR 5 & TR 6 LESS N 155 FT OF W 211 FT LESS RD BUILDING 1 Year Built Total Square Footage Number Of Bedrooms Number Of Baths Grade Condition Lot Size 218091 Views No Waterfront TOTAL LEVY RATE DISTRIBUTION Tax Year: 2018 Levy Code: 2151 Total Levy Rate: $12.51853 Total Senior Rate: $6.80724 49.70% Voter Approved Click here to see levy distribution comparison by year. TAX ROLL HISTORY Valued Year Tax Year Appraised Land Value ($) Appraised Imps Value ($) Appraised Total ($) Taxable Land Value ($) Taxable Imps Value ($) Taxable Total ($) 2017 2018 657,000 0 657,000 657,000 0 657,000 2016 2017 587,000 0 587,000 587,000 0 587,000 2015 2016 554,000 0 554,000 554,000 0 554,000 2014 2015 455,000 0 455,000 455,000 0 455,000 2013 2014 407,000 0 407,000 407,000 0 407,000 2012 2013 379,000 0 379,000 379,000 0 379,000 2011 2012 388,000 0 388,000 388,000 0 388,000 2010 2011 416,000 0 416,000 416,000 0 416,000 2009 2010 400,000 0 400,000 400,000 0 400,000 2008 2009 500,000 0 500,000 500,000 0 500,000 2007 2008 449,000 0 449,000 449,000 0 449,000 2006 2007 391,000 0 391,000 391,000 0 391,000 2005 2006 340,000 0 340,000 340,000 0 340,000 2004 2005 318,000 0 318,000 318,000 0 318,000 2003 2004 306,000 0 306,000 306,000 0 306,000 2002 2003 295,000 0 295,000 295,000 0 295,000 2001 2002 231,000 0 231,000 231,000 0 231,000 2000 2001 210,000 0 210,000 210,000 0 210,000 1999 2000 183,000 0 183,000 183,000 0 183,000 1998 1999 167,000 0 167,000 167,000 0 167,000 1997 1998 0 0 0 147,000 0 147,000 ADVERTISEMENT Reference Links: King County Taxing Districts Codes and Levies (.PDF) King County Tax Links Property Tax Advisor Washington State Department of Revenue (External link) Washington State Board of Tax Appeals (External link) Board of Appeals/Equalization Districts Report iMap Recorder's Office Scanned images of surveys and other map documents Scanned images of plats Search Kingcounty.gov Home How do I... Services About King County Departments King County Department of Assessments Information for... Residents Businesses Job seekers Volunteers King County employees Do more online Trip Planner Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... Get help Contact us Customer service Phone list Employee directory Subscribe to alerts Stay connected! View King County social media © King County, WA 2018 Privacy Accessibility Terms of use 1996 1997 0 0 0 147,000 0 147,000 1994 1995 0 0 0 114,700 0 114,700 1992 1993 0 0 0 96,500 0 96,500 1990 1991 0 0 0 91,900 0 91,900 1988 1989 0 0 0 71,200 0 71,200 1986 1987 0 0 0 71,200 0 71,200 1984 1985 0 0 0 79,100 0 79,100 1982 1983 0 0 0 79,100 0 79,100 ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email  Print Information for...Do more online Get help Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department of Assessments 500 Fourth Avenue, Suite ADM- AS-0708, Seattle, WA 98104 Office Hours: Mon - Fri 8:30 a.m. to 4:30 p.m. TEL: 206- 296-7300 FAX: 206- 296-5107 TTY: 206- 296-7888 Send us mail ADVERTISEMENT New Search Property Tax Bill Map This Property Glossary of Terms Area Report Property Detail PARCEL Parcel Number 334570-0016 Name GOODWIN DC LLC Site Address Legal HILLMANS LK WN GARDEN OF EDEN # 7 W 211 FT OF S 75 FT OF 3 & 6 LESS S 100 FT LESS E 85 FT OF N 155 FT & LESS CO RD BUILDING 1 Year Built Total Square Footage Number Of Bedrooms Number Of Baths Grade Condition Lot Size 40430 Views No Waterfront TOTAL LEVY RATE DISTRIBUTION Tax Year: 2018 Levy Code: 2151 Total Levy Rate: $12.51853 Total Senior Rate: $6.80724 49.70% Voter Approved Click here to see levy distribution comparison by year. TAX ROLL HISTORY Valued Year Tax Year Appraised Land Value ($) Appraised Imps Value ($) Appraised Total ($) Taxable Land Value ($) Taxable Imps Value ($) Taxable Total ($) 2017 2018 244,000 0 244,000 244,000 0 244,000 2016 2017 218,000 0 218,000 218,000 0 218,000 2015 2016 206,000 0 206,000 206,000 0 206,000 2014 2015 211,000 10,000 221,000 211,000 10,000 221,000 2013 2014 189,000 10,000 199,000 189,000 10,000 199,000 2012 2013 176,000 10,000 186,000 176,000 10,000 186,000 2011 2012 181,000 10,000 191,000 181,000 10,000 191,000 2010 2011 194,000 9,000 203,000 194,000 9,000 203,000 2009 2010 187,000 9,000 196,000 187,000 9,000 196,000 2008 2009 218,000 50,000 268,000 218,000 50,000 268,000 2007 2008 196,000 50,000 246,000 196,000 50,000 246,000 2006 2007 171,000 50,000 221,000 171,000 50,000 221,000 2005 2006 149,000 50,000 199,000 149,000 50,000 199,000 2004 2005 140,000 50,000 190,000 140,000 50,000 190,000 2003 2004 135,000 50,000 185,000 135,000 50,000 185,000 2002 2003 130,000 50,000 180,000 130,000 50,000 180,000 2001 2002 106,000 67,000 173,000 106,000 67,000 173,000 ADVERTISEMENT Reference Links: King County Taxing Districts Codes and Levies (.PDF) King County Tax Links Property Tax Advisor Washington State Department of Revenue (External link) Washington State Board of Tax Appeals (External link) Board of Appeals/Equalization Districts Report iMap Recorder's Office Scanned images of surveys and other map documents Scanned images of plats Search Kingcounty.gov Home How do I... Services About King County Departments King County Department of Assessments Information for... Residents Businesses Job seekers Volunteers King County employees Do more online Trip Planner Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... Get help Contact us Customer service Phone list Employee directory Subscribe to alerts Stay connected! View King County social media © King County, WA 2018 Privacy Accessibility Terms of use 2000 2001 97,000 35,000 132,000 97,000 35,000 132,000 1999 2000 85,000 35,000 120,000 85,000 35,000 120,000 1998 1999 78,000 29,000 107,000 78,000 29,000 107,000 1997 1998 0 0 0 68,500 26,000 94,500 1996 1997 0 0 0 68,500 26,000 94,500 1994 1995 0 0 0 56,000 54,800 110,800 1992 1993 0 0 0 34,200 54,800 89,000 1990 1991 0 0 0 32,600 52,200 84,800 1988 1989 0 0 0 25,200 30,900 56,100 1986 1987 0 0 0 25,200 22,500 47,700 1984 1985 0 0 0 26,000 24,200 50,200 1982 1983 0 0 0 26,000 27,800 53,800 ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email  Print Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department of Assessments 500 Fourth Avenue, Suite ADM- AS-0708, Seattle, WA 98104 Office Hours: Mon - Fri 8:30 a.m. to 4:30 p.m. TEL: 206- 296-7300 FAX: 206- 296-5107 TTY: 206- 296-7888 Send us mail ADVERTISEMENT New Search Property Tax Bill Map This Property Glossary of Terms Area Report Property Detail PARCEL Parcel Number 334570-0017 Name OGREN DAVID M JR Site Address 8314 110TH PL SE 98056 Legal HILLMANS LK WN GARDEN OF EDEN #7 PP ACT 39901012 MOBILE HOME BUILDING 1 Year Built 1989 Total Square Footage 900 Number Of Bedrooms 1 Number Of Baths 1.00 Grade 6 Low Average Condition Average Lot Size 75755 Views No Waterfront TOTAL LEVY RATE DISTRIBUTION Tax Year: 2018 Levy Code: 2151 Total Levy Rate: $12.51853 Total Senior Rate: $6.80724 49.70% Voter Approved Click here to see levy distribution comparison by year. TAX ROLL HISTORY Valued Year Tax Year Appraised Land Value ($) Appraised Imps Value ($) Appraised Total ($) Taxable Land Value ($) Taxable Imps Value ($) Taxable Total ($) 2017 2018 333,000 167,000 500,000 333,000 167,000 500,000 2016 2017 298,000 130,000 428,000 298,000 130,000 428,000 2015 2016 282,000 123,000 405,000 282,000 123,000 405,000 2014 2015 294,000 110,000 404,000 294,000 110,000 404,000 2013 2014 263,000 87,000 350,000 263,000 87,000 350,000 2012 2013 245,000 102,000 347,000 245,000 102,000 347,000 2011 2012 251,000 105,000 356,000 251,000 105,000 356,000 2010 2011 269,000 110,000 379,000 269,000 110,000 379,000 2009 2010 259,000 107,000 366,000 259,000 107,000 366,000 2008 2009 277,000 297,000 574,000 277,000 297,000 574,000 2007 2008 249,000 266,000 515,000 249,000 266,000 515,000 2006 2007 217,000 223,000 440,000 217,000 223,000 440,000 2005 2006 189,000 193,000 382,000 189,000 193,000 382,000 2004 2005 177,000 182,000 359,000 177,000 182,000 359,000 2003 2004 171,000 171,000 342,000 171,000 171,000 342,000 2002 2003 165,000 139,000 304,000 165,000 139,000 304,000 2001 2002 132,000 232,000 364,000 132,000 232,000 364,000 2000 2001 120,000 194,000 314,000 120,000 194,000 314,000 1999 2000 105,000 167,000 272,000 105,000 167,000 272,000 ADVERTISEMENT Reference Links: King County Taxing Districts Codes and Levies (.PDF) King County Tax Links Property Tax Advisor Washington State Department of Revenue (External link) Washington State Board of Tax Appeals (External link) Board of Appeals/Equalization Districts Report iMap Recorder's Office Scanned images of surveys and other map documents Scanned images of plats Search Kingcounty.gov Home How do I... Services About King County Departments King County Department of Assessments Information for... Residents Businesses Job seekers Volunteers King County employees Do more online Trip Planner Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... Get help Contact us Customer service Phone list Employee directory Subscribe to alerts Stay connected! View King County social media © King County, WA 2018 Privacy Accessibility Terms of use 1998 1999 96,000 147,000 243,000 96,000 147,000 243,000 1997 1998 0 0 0 85,000 129,000 214,000 1996 1997 0 0 0 85,000 129,000 214,000 1995 1996 0 0 0 66,400 102,600 169,000 1994 1995 0 0 0 66,400 95,436 161,836 1992 1993 0 0 0 44,000 95,436 139,436 1991 1992 0 0 0 41,900 88,276 130,176 1990 1991 0 0 0 41,900 88,276 130,176 1989 1990 0 0 0 32,400 70,992 103,392 1988 1989 0 0 0 32,400 39,292 71,692 1987 1988 0 0 0 32,400 36,991 69,391 1986 1987 0 0 0 32,400 34,176 66,576 1985 1986 0 0 0 8,400 32,860 41,260 1984 1985 0 0 0 8,400 0 8,400 1982 1983 0 0 0 8,400 0 8,400 ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email  Print Information for...Do more online Get help Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department of Assessments 500 Fourth Avenue, Suite ADM- AS-0708, Seattle, WA 98104 Office Hours: Mon - Fri 8:30 a.m. to 4:30 p.m. TEL: 206- 296-7300 FAX: 206- 296-5107 TTY: 206- 296-7888 Send us mail ADVERTISEMENT New Search Property Tax Bill Map This Property Glossary of Terms Area Report Property Detail PARCEL Parcel Number 334570-0018 Name LUND JEFF & JONI Site Address 4130 LINCOLN AVE NE 98056 Legal HILLMANS LK WN GARDEN OF EDEN #7 BUILDING 1 Year Built 1982 Total Square Footage 2580 Number Of Bedrooms 3 Number Of Baths 2.00 Grade 8 Good Condition Average Lot Size 75698 Views No Waterfront TOTAL LEVY RATE DISTRIBUTION Tax Year: 2018 Levy Code: 2151 Total Levy Rate: $12.51853 Total Senior Rate: $6.80724 49.70% Voter Approved Click here to see levy distribution comparison by year. TAX ROLL HISTORY Valued Year Tax Year Appraised Land Value ($) Appraised Imps Value ($) Appraised Total ($) Taxable Land Value ($) Taxable Imps Value ($) Taxable Total ($) 2017 2018 292,000 353,000 645,000 292,000 353,000 645,000 2016 2017 261,000 291,000 552,000 261,000 291,000 552,000 2015 2016 247,000 275,000 522,000 247,000 275,000 522,000 2014 2015 255,000 219,000 474,000 255,000 219,000 474,000 2013 2014 228,000 182,000 410,000 228,000 182,000 410,000 2012 2013 213,000 166,000 379,000 213,000 166,000 379,000 2011 2012 219,000 169,000 388,000 219,000 169,000 388,000 2010 2011 235,000 178,000 413,000 235,000 178,000 413,000 2009 2010 226,000 172,000 398,000 226,000 172,000 398,000 2008 2009 235,000 384,000 619,000 235,000 384,000 619,000 2007 2008 211,000 345,000 556,000 211,000 345,000 556,000 2006 2007 184,000 291,000 475,000 184,000 291,000 475,000 2005 2006 160,000 278,000 438,000 160,000 278,000 438,000 2004 2005 150,000 261,000 411,000 150,000 261,000 411,000 2003 2004 145,000 246,000 391,000 145,000 246,000 391,000 2002 2003 140,000 235,000 375,000 140,000 235,000 375,000 2001 2002 132,000 223,000 355,000 132,000 223,000 355,000 2000 2001 120,000 201,000 321,000 120,000 201,000 321,000 1999 2000 105,000 187,000 292,000 105,000 187,000 292,000 ADVERTISEMENT Reference Links: King County Taxing Districts Codes and Levies (.PDF) King County Tax Links Property Tax Advisor Washington State Department of Revenue (External link) Washington State Board of Tax Appeals (External link) Board of Appeals/Equalization Districts Report iMap Recorder's Office Scanned images of surveys and other map documents Scanned images of plats Search Kingcounty.gov Home How do I... Services About King County Departments King County Department of Assessments Information for... Residents Businesses Job seekers Volunteers King County employees Do more online Trip Planner Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... Get help Contact us Customer service Phone list Employee directory Subscribe to alerts Stay connected! View King County social media © King County, WA 2018 Privacy Accessibility Terms of use 1998 1999 96,000 174,000 270,000 96,000 174,000 270,000 1997 1998 0 0 0 85,000 153,000 238,000 1996 1997 0 0 0 85,000 153,000 238,000 1994 1995 0 0 0 66,400 147,600 214,000 1992 1993 0 0 0 42,000 147,600 189,600 1990 1991 0 0 0 40,000 140,600 180,600 1988 1989 0 0 0 31,000 97,300 128,300 1986 1987 0 0 0 31,000 91,000 122,000 1984 1985 0 0 0 34,400 89,400 123,800 1983 1984 0 0 0 34,400 49,300 83,700 1982 1983 0 0 0 34,400 64,600 99,000 ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email  Print Information for...Do more online Get help Fair, Equitable, and Understandable Property Valuations You're in: Assessor >> Look up Property Info >> eReal Property Department of Assessments 500 Fourth Avenue, Suite ADM- AS-0708, Seattle, WA 98104 Office Hours: Mon - Fri 8:30 a.m. to 4:30 p.m. TEL: 206- 296-7300 FAX: 206- 296-5107 TTY: 206- 296-7888 Send us mail ADVERTISEMENT New Search Property Tax Bill Map This Property Glossary of Terms Area Report Property Detail PARCEL Parcel Number 334570-0020 Name GOODWIN DC LLC Site Address Legal HILLMANS LK WN GARDEN OF EDEN # 7 N 120 FT LESS W 50 FT OF 4 BUILDING 1 Year Built Total Square Footage Number Of Bedrooms Number Of Baths Grade Condition Lot Size 29562 Views No Waterfront TOTAL LEVY RATE DISTRIBUTION Tax Year: 2018 Levy Code: 2151 Total Levy Rate: $12.51853 Total Senior Rate: $6.80724 49.70% Voter Approved Click here to see levy distribution comparison by year. TAX ROLL HISTORY Valued Year Tax Year Appraised Land Value ($) Appraised Imps Value ($) Appraised Total ($) Taxable Land Value ($) Taxable Imps Value ($) Taxable Total ($) 2017 2018 215,000 0 215,000 215,000 0 215,000 2016 2017 192,000 0 192,000 192,000 0 192,000 2015 2016 182,000 0 182,000 182,000 0 182,000 2014 2015 181,000 0 181,000 181,000 0 181,000 2013 2014 162,000 0 162,000 162,000 0 162,000 2012 2013 151,000 0 151,000 151,000 0 151,000 2011 2012 155,000 0 155,000 155,000 0 155,000 2010 2011 166,000 0 166,000 166,000 0 166,000 2009 2010 160,000 0 160,000 160,000 0 160,000 2008 2009 183,000 0 183,000 183,000 0 183,000 2007 2008 165,000 0 165,000 165,000 0 165,000 2006 2007 144,000 0 144,000 144,000 0 144,000 2005 2006 126,000 0 126,000 126,000 0 126,000 2004 2005 118,000 0 118,000 118,000 0 118,000 2003 2004 114,000 0 114,000 114,000 0 114,000 2002 2003 110,000 0 110,000 110,000 0 110,000 2001 2002 80,000 0 80,000 80,000 0 80,000 2000 2001 73,000 0 73,000 73,000 0 73,000 1999 2000 64,000 0 64,000 64,000 0 64,000 1998 1999 59,000 0 59,000 59,000 0 59,000 1997 1998 0 0 0 52,000 0 52,000 1996 1997 0 0 0 52,000 0 52,000 1994 1995 0 0 0 41,700 0 41,700 1992 1993 0 0 0 30,500 0 30,500 ADVERTISEMENT Reference Links: King County Taxing Districts Codes and Levies (.PDF) King County Tax Links Property Tax Advisor Washington State Department of Revenue (External link) Washington State Board of Tax Appeals (External link) Board of Appeals/Equalization Districts Report iMap Recorder's Office Scanned images of surveys and other map documents Scanned images of plats Search Kingcounty.gov Home How do I... Services About King County Departments King County Department of Assessments Information for... Residents Businesses Job seekers Volunteers King County employees Do more online Trip Planner Property tax information & payment Jail inmate look up Parcel viewer or iMap Public records More online tools... Get help Contact us Customer service Phone list Employee directory Subscribe to alerts Stay connected! View King County social media © King County, WA 2018 Privacy Accessibility Terms of use 1990 1991 0 0 0 29,000 0 29,000 1988 1989 0 0 0 22,500 0 22,500 1986 1987 0 0 0 22,500 0 22,500 1984 1985 0 0 0 8,800 0 8,800 1982 1983 0 0 0 8,800 0 8,800 ADVERTISEMENT Updated: March 17, 2016  Share  Tweet  Email  Print Information for...Do more online Get help Appendix B Resource Review & Off-site Analysis Documentation 9,0281505Flood Hazard Areas MapThis map is a user generated static output from an Internet mapping site and is forreference only. Data layers that appear on this map may or may not be accurate,current, or otherwise reliable.WGS_1984_Web_Mercator_Auxiliary_SphereNotesNone5/24/2018Legend1023 512THIS MAP IS NOT TO BE USED FOR NAVIGATIONFeet1023Information Technology - GIS0RentonMapSupport@Rentonwa.govCity and County BoundaryParcelsFloodwaySpecial Flood Hazard Areas (100 year flood)Other Flood Areas (Zone X - 500 year flood) 9,0281505Streams and Wetlands MapThis map is a user generated static output from an Internet mapping site and is forreference only. Data layers that appear on this map may or may not be accurate,current, or otherwise reliable.WGS_1984_Web_Mercator_Auxiliary_SphereNotesNone5/24/2018Legend1023 512THIS MAP IS NOT TO BE USED FOR NAVIGATIONFeet1023Information Technology - GIS0RentonMapSupport@Rentonwa.govCity and County BoundaryParcelsStreams (Classified)Type SType FType NpType NsWetlands 9,0281505City of Renton Print map TemplateThis map is a user generated static output from an Internet mapping site and is forreference only. Data layers that appear on this map may or may not be accurate,current, or otherwise reliable.WGS_1984_Web_Mercator_Auxiliary_SphereNotesNone5/24/2018Legend1023 512THIS MAP IS NOT TO BE USED FOR NAVIGATIONFeet1023Information Technology - GIS0RentonMapSupport@Rentonwa.govCity and County BoundaryParcelsZoningRC-Resource ConservationR1-Residential 1 du/acR4-Residential 4 du/acR6-Residential - 6 DU/ACR8-Residential 8 du/acR10-Residential 10 du/acR14-Residential 14 du/acRMF-Residential Multi-FamilyRMH-Residential Manufactured HomesCN-Commercial NeighborhoodCV-Center VillageCA-Commercial ArterialUC-Urban CenterCD-Center DowntownAuto Mall AAuto Mall BAuto Mall CEmployment Area ValleyCity Center Sign Regulation AreaUrban Design District AUrban Design District BUrban Design District CUrban Design District DUrban SeparatorDowntown Business District 9,0281505Landslide Hazard Areas MapThis map is a user generated static output from an Internet mapping site and is forreference only. Data layers that appear on this map may or may not be accurate,current, or otherwise reliable.WGS_1984_Web_Mercator_Auxiliary_SphereNotesNone5/24/2018Legend1023 512THIS MAP IS NOT TO BE USED FOR NAVIGATIONFeet1023Information Technology - GIS0RentonMapSupport@Rentonwa.govCity and County BoundaryParcelsLandslideVERY HIGHHIGHMODERATEUNCLASSIFED Appendix C Special Reports and Studies Appendix D Detention Facility Sizing ————————————————————————————————— MGS FLOOD PROJECT REPORT Program Version: MGSFlood 4.46 Program License Number: 200210008 Project Simulation Performed on: 04/24/2019 11:16 AM Report Generation Date: 04/24/2019 11:16 AM ————————————————————————————————— Input File Name: 18054 MGS Flood.fld Project Name: Canopy Analysis Title: Comments: ———————————————— PRECIPITATION INPUT ———————————————— Computational Time Step (Minutes): 15 Extended Precipitation Time Series Selected Climatic Region Number: 15 Full Period of Record Available used for Routing Precipitation Station : 96004005 Puget East 40 in_5min 10/01/1939-10/01/2097 Evaporation Station : 961040 Puget East 40 in MAP Evaporation Scale Factor : 0.750 HSPF Parameter Region Number: 1 HSPF Parameter Region Name : USGS Default ********** Default HSPF Parameters Used (Not Modified by User) *************** ********************** WATERSHED DEFINITION *********************** Predevelopment/Post Development Tributary Area Summary Predeveloped Post Developed Total Subbasin Area (acres) 9.260 9.260 Area of Links that Include Precip/Evap (acres) 0.000 0.000 Total (acres) 9.260 9.260 ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 ---------- Subbasin : Predev Offsite ---------- -------Area (Acres) -------- Till Forest 0.870 ---------------------------------------------- Subbasin Total 0.870 ---------- Subbasin : Predev Onsite & Upstream ---------- -------Area (Acres) -------- Till Forest 8.390 ---------------------------------------------- Subbasin Total 8.390 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 5 ---------- Subbasin : Dev Onsite Subbasin ---------- -------Area (Acres) -------- Till Forest 0.600 Till Grass 3.480 Impervious 3.620 ---------------------------------------------- Subbasin Total 7.700 ---------- Subbasin : Dev Offsite Subbasin ---------- -------Area (Acres) -------- Till Grass 0.070 Impervious 0.300 ---------------------------------------------- Subbasin Total 0.370 ---------- Subbasin : Offsite Bypass ---------- -------Area (Acres) -------- Till Grass 0.040 Impervious 0.240 ---------------------------------------------- Subbasin Total 0.280 ---------- Subbasin : Upstream ---------- -------Area (Acres) -------- Till Forest 0.680 ---------------------------------------------- Subbasin Total 0.680 ---------- Subbasin : Offsite Addition ---------- -------Area (Acres) -------- Till Grass 0.010 Impervious 0.220 ---------------------------------------------- Subbasin Total 0.230 ************************* LINK DATA ******************************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ------------------------------------------ Link Name: POC Link Type: Copy Downstream Link: None ************************* LINK DATA ******************************* ----------------------SCENARIO: POSTDEVELOPED Number of Links: 3 ------------------------------------------ Link Name: Vault 2 Link Type: Structure Downstream Link Name: POC Prismatic Pond Option Used Pond Floor Elevation (ft) : 100.00 Riser Crest Elevation (ft) : 104.50 Max Pond Elevation (ft) : 105.50 Storage Depth (ft) : 4.50 Pond Bottom Length (ft) : 40.0 Pond Bottom Width (ft) : 120.0 Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00 Bottom Area (sq-ft) : 4800. Area at Riser Crest El (sq-ft) : 4,800. (acres) : 0.110 Volume at Riser Crest (cu-ft) : 21,600. (ac-ft) : 0.496 Area at Max Elevation (sq-ft) : 4800. (acres) : 0.110 Vol at Max Elevation (cu-ft) : 26,400. (ac-ft) : 0.606 Massmann Infiltration Option Used Hydraulic Conductivity (in/hr) : 0.00 Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 18.00 Common Length (ft) : 0.000 Riser Crest Elevation : 104.50 ft Hydraulic Structure Geometry Number of Devices: 4 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 1.50 Orientation : Horizontal Elbow : No ---Device Number 2 --- Device Type : Circular Orifice Control Elevation (ft) : 101.60 Diameter (in) : 2.50 Orientation : Horizontal Elbow : Yes ---Device Number 3 --- Device Type : Circular Orifice Control Elevation (ft) : 102.60 Diameter (in) : 1.63 Orientation : Horizontal Elbow : Yes ---Device Number 4 --- Device Type : Circular Orifice Control Elevation (ft) : 103.60 Diameter (in) : 0.87 Orientation : Horizontal Elbow : Yes ------------------------------------------ Link Name: Vault 1 Link Type: Structure Downstream Link Name: Vault 2 Prismatic Pond Option Used Pond Floor Elevation (ft) : 100.00 Riser Crest Elevation (ft) : 110.00 Max Pond Elevation (ft) : 111.00 Storage Depth (ft) : 10.00 Pond Bottom Length (ft) : 60.0 Pond Bottom Width (ft) : 136.4 Pond Side Slopes (ft/ft) : L1= 0.00 L2= 0.00 W1= 0.00 W2= 0.00 Bottom Area (sq-ft) : 8181. Area at Riser Crest El (sq-ft) : 8,181. (acres) : 0.188 Volume at Riser Crest (cu-ft) : 81,810. (ac-ft) : 1.878 Area at Max Elevation (sq-ft) : 8181. (acres) : 0.188 Vol at Max Elevation (cu-ft) : 89,991. (ac-ft) : 2.066 Massmann Infiltration Option Used Hydraulic Conductivity (in/hr) : 0.00 Depth to Water Table (ft) : 100.00 Bio-Fouling Potential : Low Maintenance : Average or Better Riser Geometry Riser Structure Type : Circular Riser Diameter (in) : 18.00 Common Length (ft) : 0.000 Riser Crest Elevation : 110.00 ft Hydraulic Structure Geometry Number of Devices: 5 ---Device Number 1 --- Device Type : Circular Orifice Control Elevation (ft) : 100.00 Diameter (in) : 1.13 Orientation : Horizontal Elbow : No ---Device Number 2 --- Device Type : Circular Orifice Control Elevation (ft) : 106.00 Diameter (in) : 1.25 Orientation : Horizontal Elbow : Yes ---Device Number 3 --- Device Type : Circular Orifice Control Elevation (ft) : 107.00 Diameter (in) : 1.25 Orientation : Horizontal Elbow : Yes ---Device Number 4 --- Device Type : Circular Orifice Control Elevation (ft) : 108.00 Diameter (in) : 1.25 Orientation : Horizontal Elbow : Yes ---Device Number 5 --- Device Type : Circular Orifice Control Elevation (ft) : 109.00 Diameter (in) : 2.00 Orientation : Horizontal Elbow : Yes ------------------------------------------ Link Name: POC Link Type: Copy Downstream Link: None **********************FLOOD FREQUENCY AND DURATION STATISTICS******************* ----------------------SCENARIO: PREDEVELOPED Number of Subbasins: 2 Number of Links: 1 ********** Subbasin: Predev Offsite ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 1.854E-02 5-Year 3.022E-02 10-Year 4.071E-02 25-Year 5.162E-02 50-Year 6.587E-02 100-Year 7.139E-02 200-Year 0.111 ********** Subbasin: Predev Onsite & Upstream ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.179 5-Year 0.291 10-Year 0.393 25-Year 0.498 50-Year 0.635 100-Year 0.688 200-Year 1.072 ********** Link: POC ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.197 5-Year 0.322 10-Year 0.433 25-Year 0.549 50-Year 0.701 100-Year 0.760 200-Year 1.183 ----------------------SCENARIO: POSTDEVELOPED Number of Subbasins: 5 Number of Links: 3 ********** Subbasin: Dev Onsite Subbasin ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 1.657 5-Year 2.171 10-Year 2.660 25-Year 3.603 50-Year 4.607 100-Year 5.550 200-Year 5.655 ********** Subbasin: Dev Offsite Subbasin ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.118 5-Year 0.151 10-Year 0.178 25-Year 0.236 50-Year 0.279 100-Year 0.343 200-Year 0.350 ********** Subbasin: Offsite Bypass ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.235E-02 5-Year 0.119 10-Year 0.139 25-Year 0.182 50-Year 0.219 100-Year 0.265 200-Year 0.272 ********** Subbasin: Upstream ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 1.449E-02 5-Year 2.362E-02 10-Year 3.182E-02 25-Year 4.035E-02 50-Year 5.149E-02 100-Year 5.580E-02 200-Year 8.685E-02 ********** Subbasin: Offsite Addition ********** Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 8.299E-02 5-Year 0.107 10-Year 0.123 25-Year 0.155 50-Year 0.194 100-Year 0.228 200-Year 0.235 ********** Link: Vault 2 ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.257 5-Year 0.347 10-Year 0.432 25-Year 0.543 50-Year 0.781 100-Year 1.181 200-Year 1.205 ********** Link: Vault 2 ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.116 5-Year 0.185 10-Year 0.246 25-Year 0.369 50-Year 0.422 100-Year 0.466 200-Year 0.625 ********** Link: Vault 2 ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 101.083 1.11-Year 101.162 1.25-Year 101.361 2.00-Year 101.660 3.33-Year 101.766 5-Year 101.998 10-Year 102.503 25-Year 103.276 50-Year 103.727 100-Year 104.079 ********** Link: Vault 1 ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 1.664 5-Year 2.182 10-Year 2.673 25-Year 3.615 50-Year 4.674 100-Year 5.551 200-Year 5.660 ********** Link: Vault 1 ********** Link Outflow 1 Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 9.537E-02 5-Year 0.178 10-Year 0.250 25-Year 0.385 50-Year 0.662 100-Year 1.067 200-Year 1.096 ********** Link: Vault 1 ********** Link WSEL Stats WSEL Frequency Data(ft) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) WSEL Peak (ft) ====================================== 1.05-Year 103.262 1.11-Year 103.643 1.25-Year 104.322 2.00-Year 106.094 3.33-Year 107.013 5-Year 107.697 10-Year 108.708 25-Year 109.724 50-Year 110.032 100-Year 110.117 ********** Link: POC ********** Link Inflow Frequency Stats Flood Frequency Data(cfs) (Recurrence Interval Computed Using Gringorten Plotting Position) Tr (yrs) Flood Peak (cfs) ====================================== 2-Year 0.159 5-Year 0.226 10-Year 0.293 25-Year 0.373 50-Year 0.434 100-Year 0.476 200-Year 0.642 ***********Groundwater Recharge Summary ************* Recharge is computed as input to Perlnd Groundwater Plus Infiltration in Structures Total Predeveloped Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Predev Offsite 150.013 Subbasin: Predev Onsite & Upst1446.679 Link: POC 0.000 _____________________________________ Total: 1596.692 Total Post Developed Recharge During Simulation Model Element Recharge Amount (ac-ft) ----------------------------------------------------------------------------------------------- Subbasin: Dev Onsite Subbasin 528.750 Subbasin: Dev Offsite Subbasin 8.555 Subbasin: Offsite Bypass 4.888 Subbasin: Upstream 117.252 Subbasin: Offsite Addition 1.222 Link: Vault 2 0.000 Link: Vault 1 0.000 Link: POC 0.000 _____________________________________ Total: 660.667 Total Predevelopment Recharge is Greater than Post Developed Average Recharge Per Year, (Number of Years= 158) Predeveloped: 10.106 ac-ft/year, Post Developed: 4.181 ac-ft/year ***********Water Quality Facility Data ************* ----------------------SCENARIO: PREDEVELOPED Number of Links: 1 ********** Link: POC ********** Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 842.82 Inflow Volume Including PPT-Evap (ac-ft): 842.82 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 842.82 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ----------------------SCENARIO: POSTDEVELOPED Number of Links: 3 ********** Link: Vault 2 ********** Basic Wet Pond Volume (91% Exceedance): 7316. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 10974. cu-ft Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2688.24 Inflow Volume Including PPT-Evap (ac-ft): 2688.24 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2688.16 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: Vault 1 ********** Basic Wet Pond Volume (91% Exceedance): 21115. cu-ft Computed Large Wet Pond Volume, 1.5*Basic Volume: 31673. cu-ft Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2439.36 Inflow Volume Including PPT-Evap (ac-ft): 2439.36 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2439.01 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ********** Link: POC ********** Infiltration/Filtration Statistics-------------------- Inflow Volume (ac-ft): 2803.81 Inflow Volume Including PPT-Evap (ac-ft): 2803.81 Total Runoff Infiltrated (ac-ft): 0.00, 0.00% Total Runoff Filtered (ac-ft): 0.00, 0.00% Primary Outflow To Downstream System (ac-ft): 2803.81 Secondary Outflow To Downstream System (ac-ft): 0.00 Percent Treated (Infiltrated+Filtered)/Total Volume: 0.00% ***********Compliance Point Results ************* Scenario Predeveloped Compliance Link: POC Scenario Postdeveloped Compliance Link: POC *** Point of Compliance Flow Frequency Data *** Recurrence Interval Computed Using Gringorten Plotting Position Predevelopment Runoff Postdevelopment Runoff Tr (Years) Discharge (cfs) Tr (Years) Discharge (cfs) ---------------------------------------------------------------------------------------------------------------------- 2-Year 0.197 2-Year 0.159 5-Year 0.322 5-Year 0.226 10-Year 0.433 10-Year 0.293 25-Year 0.549 25-Year 0.373 50-Year 0.701 50-Year 0.434 100-Year 0.760 100-Year 0.476 200-Year 1.183 200-Year 0.642 ** Record too Short to Compute Peak Discharge for These Recurrence Intervals **** Flow Duration Performance **** Excursion at Predeveloped 50%Q2 (Must be Less Than or Equal to 0%): -8.1% PASS Maximum Excursion from 50%Q2 to Q2 (Must be Less Than or Equal to 0%): -4.7% PASS Maximum Excursion from Q2 to Q50 (Must be less than 10%): 0.0% PASS Percent Excursion from Q2 to Q50 (Must be less than 50%): 0.0% PASS ------------------------------------------------------------------------------------------------- MEETS ALL FLOW DURATION DESIGN CRITERIA: PASS ------------------------------------------------------------------------------------------------- Appendix E Stormwater Pollution Prevention Plan (SWPPP)