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M_13803 SE 208th Street_250114
TECHNICAL INFORMATION REPORT FOR SOOS CREEK TRAIL PHASE 5A EXTENSION CITY OF RENTON KING COUNTY, WASHINGTON October 27, 2025 Prepared for: King County Department of Natural Resources and Parks King Street Center, Room 6500 201 South Jackson Street Seattle, WA 98104-3855 Contact: Thomas Early (206) 477-7555 Prepared by: 1700 7th Ave, Suite 2075 Seattle, Washington 98101 Contact: Viet Ly, PE (206) 324-5500 10/27/2025 ii Table of Contents SECTION 1 - PROJECT OVERVIEW ............................................................................................ 2 SECTION 2 - CONDITIONS AND REQUIREMENTS SUMMARY ........................................... 3 SECTION 3 - OFFSITE ANALYSIS .............................................................................................. 5 SECTION - 4 FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ...................................................................... 7 SECTION 5 - CONVEYANCE SYSTEM ANALYSIS AND DESIGN ....................................... 10 SECTION 6 - SPECIAL REPORTS AND STUDIES ................................................................... 10 SECTION 7 - OTHER PERMITS .................................................................................................. 10 SECTION 8 - CSWPP PLAN ANALYSIS AND DESIGN .......................................................... 10 SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ................................................................................................................................. 12 SECTION 10 OPERATION AND MAINTENANCE MANUAL ................................................ 12 EXHIBITS Exhibit 1 Existing Land Use Conditions Exhibit 2 Existing Site Drainage Conditions Exhibit 3 Proposed Site Land Use Conditions Exhibit 4 Proposed Storm Drainage Site Plan FIGURES Figure 1 TIR Worksheet Figure 2 Vicinity Map Figure 3 Drainage Basins Figure 4 Site Soil APPENDICES A TIR Worksheet (same as Figure 1) B Downstream Analysis Supporting Documents C Geotechnical Report (reference only) D Design Calculations E WWHM Modeling F Operation and Maintenance Manual 2 SECTION 1 - PROJECT OVERVIEW Background This Technical Information Report (TIR) describes the drainage management requirements, facilities and procedures for a proposed segment of the Soos Creek Trail Phase 5A Project. Phase 5A will extend the trail from SE 192nd Street to SE 186th Street. See project summary information on the TIR Worksheet included as Figure 1. This proposed shared-use trail segment is predominantly on King County Parks properties located within the City of Renton (COR) jurisdiction. See Figure 2 for project vicinity map. This TIR is prepared in conformance with the City of Renton 2022 Surface Water Design Manual (City Drainage Manual). Existing The Site occupies low-lying land and adjacent wetland that receive runoff from subbasins east and west of Big Soos Creek. The eastern and southern boundaries of the Site are also the COR and King County jurisdictional boundary. The eastern subbasin is in King County jurisdiction (Figure 3A) and the western subbasin is in COR jurisdiction (Figure 3B). Big Soos Creek flows north to south toward an existing culvert that crosses under SE 192nd Street. This culvert is the project site point of discharge. According to the USDA Web Soil Survey maps, soils at the project site are generally mapped as Alderwood gravelly sandy loams in the upland portions of the proposed trail, with Norma sandy loam mapped in the riparian wetlands associated with Big Soos Creek (Figure 4). The soils are erodible, so appropriate TESC measures will be taken during construction. Section 4 of this Report describes more characteristics of the Site existing conditions. Proposed Site improvements consist of a paved trail and associated drainage facilities. Storm water from the proposed trail will be dispersed into the adjacent natural area bordering Big Soos Creek. This will mimic the natural drainage system of the project site in that there are currently no defined, concentrated discharge points, with the exception of some cross drains which drain residential development from the west. Off-site drainage will be collected on the uphill (west) side of the trail and conveyed under the trail through trail-bed permeable granular railroad ballast drains. This is proposed at two low point locations along the trail. Flow through this trail-bed drain is discharged via rock dispersion outlets. The proposed trail project is a linear feature (approximately 2,400 feet of trail) that traverses in a north-south direction through several King County Parks-owned parcels. The existing land use and drainage conditions are shown on Exhibit 1. There is no existing 3 impervious surface at the site; it is currently vegetated, with pasture and low-growing shrubs along the BPA transmission line and wooded areas on both sides of the power line. The total area to be disturbed is 1.70 acres, while the new hard surface area is 0.79 acres. Section 4 of this Report describes more characteristics of the Site proposed conditions. SECTION 2 - CONDITIONS AND REQUIREMENTS SUMMARY This report and the facilities and procedures described have been prepared in conformance with the current surface water regulations of the City of Renton including the 2022 Surface Water Design Manual. The majority length of the proposed Soos Creek trail segment from SE 192 Street at the southern end to SE 186th Street at the northern end is within the COR jurisdiction. A small portion of proposed trail improvements at the mid-block crossing is within South 192nd Street right-of-way and regulated by King County Roads Division. Based on site characteristics the project is subject to Full Drainage Review, with applicable requirements as summarized in this section. The project site contains one (1) Threshold Discharge Area (TDA 1 discharging to adjacent Big Soos Creek). The full set of Core and Supplemental Requirements must be addressed in Full Drainage Review. Core Requirement 1: Discharge at the Natural Location Under natural, pre-developed conditions, runoff from the proposed trail alignment is not concentrated and flows in a dispersed manner to the riparian/wetland buffers of Big Soos Creek. The existing natural topography based on King County iMap GIS indicates Big Soos Creek flows from north to south and leaves the project site via a culvert located under South 192nd Street. This culvert discharge location will be preserved by the project and form the basis of defining the project TDA. The project will not alter the existing drainage pattern, except to collect some offsite runoff from the uphill side of the trail and convey it under the trail using trail bed drains as described in Section 1. The runoff from an approximately 350-ft segment of trail will be somewhat more concentrated (by use of rock dispersion outlets) than under pre-developed conditions but should not cause downstream impacts. Most of the trail improvements will disperse runoff toward Big Soos Creek as in the natural conditions. Core Requirement 2: Offsite Analysis A Level 1 Downstream Analysis, documented in Section 3, is required. 4 Core Requirement 3: Flow Control The project is located in the Duration Flow Control Standard (Forested Conditions) Area (matching Forested Site Conditions) based on the City Flow Control Applications Map and is subject to the Flow Control Duration Standard (meet historic forest condition runoff durations for the range of flows from 50% of the 2-year flow to the 50-year flow and match peaks for the 2-year and 10-year return periods). No drainage conveyance system nuisance, severe erosion, or severe flooding problems were identified through downstream analysis (pending field study). There is likely a small potential impact to wetland hydrology, as determined through a Critical Area Review per RMC Title IV (per Table 1.2.3.A of the Drainage Manual). Reference 5 of the Drainage Manual states that “If a project or threshold discharge area within a project discharging to a wetland require flow control facility per Core Requirement #3 of the SWDM, the project must apply the following Wetland Hydroperiod Protection”. Because this project does not require flow control (see Section 4), additional flow control is not required. Core Requirement 4: Conveyance System New conveyances and culverts are required to be sized to convey the 25-year return interval peak flow rate. Core Requirement 5: Erosion and Sediment Control All standards from the City Drainage Manual apply. Section 8 describes how the TESC and CSWPPP plans will meet these standards. Core Requirement 6: Maintenance and Operations King County WLRD – King County Parks Department will be responsible for maintenance and operation of drainage facilities. An Operations and Maintenance Manual is included in Appendix F. Core Requirement 7: Financial Guarantees and Liability King County WLRD – King County Parks Department will comply with this Core Requirement. Core Requirement 8: Water Quality The project is located in the Basic Water Quality area as shown on the Water Quality Applications Map. The proposed trail is considered non-pollution generating impervious surface (NPGIS). Therefore, no treatment BMPs are required for the proposed trail. The project also consists of new sidewalk, curb & gutter, and associated replacement of existing asphalt concrete pavement along the north side of SE 192nd Street. This portion of 5 the Project Site is within unincorporated King County and KC Roads right-of-way. The existing paved roadway and shoulder is considered existing pollution generating impervious surface (PGIS). The proposed trail portion and sidewalk along SE 192nd Street replaces existing PGIS but does not create new PGIS. Approximately 2,700 square feet of PGIS is replaced, with 1,050 square feet of which is converted to NPGIS. Therefore, no water quality treatment BMPs are required per section 1.2.8 of the KC Surface Water Design Manual. Special Requirement 1: Other Adopted Area-Specific Requirements None Applicable Special Requirement 2: Flood Hazard Area Delineation The King County/FEMA base-flood elevation is indicated on Exhibit 4. The proposed Soos Creek Trail segment within COR is outside the floodplain. There is no fill proposed in the flood plain. Special Requirement 3: Flood Protection Facilities Not applicable. Special Requirement 4: Source Controls Not applicable. Special Requirement 5: Oil Control Not applicable. SECTION 3 - OFFSITE ANALYSIS A Level 1 qualitative downstream analysis was performed. The analysis included the following four tasks: • Task 1: Define and map study area • Task 2: Review available information • Task 3: Field investigate the study area • Task 4: Describe the drainage system and its existing and predicted drainage and water quality problems Task 1 – Define and Map Study Area Runoff from the project site discharges to adjacent wetland and Big Soos Creek that flows south through an existing storm drain culvert that crosses under SE 192nd Street. This culvert is considered the point of discharge of the Site. A minimum one-mile downstream 6 from the point of discharge along Big Soos Creek flow path is shown in Figure B.1 (Appendix B). The 1-mile downstream location places the study limit of resources review (Task 2). Figure B.2 of Appendix B shows the downstream flow path from the point of discharge a distance of ¼-mile for purposes of the field inspection (Tasks 3 and 4). Task 2 – Review Available Information • Floodplains and floodways have been mapped for Big Soos Creek in the vicinity of the project. These features are shown on the site plans. The proposed Soos Creek Trail segment does not cross the Creek. A portion of the trail is located within the wetland on an approximately 100-foot elevated boardwalk segment. • Sensitive Areas (from KC GIS iMap) o Wetlands have been delineated along Big Soos Creek in the vicinity of the proposed trail. Wetland boundaries are shown on the site plans. o The Big Soos Creek corridor is identified as a Wildlife Network. • Big Soos Creek within the study area is not listed on the Washington State Department of Ecology’s latest published Clean Water Act Section 303d list of impaired water bodies. • Critical Areas o No erosion hazard and landslide hazard are identified for the project site from reviewing City of Renton maps. Erosion hazard is identified over the development west of the project site (Appendix B, Figure B.3). o A portion of the trail, and the downstream study area of the trail, is adjacent to a Category 1 Critical Aquifer Recharge Area (Appendix B, Figure B.4). The trail development will have no impact on aquifer recharge or groundwater contamination. o Seismic hazard is identified over the project site and downstream area according to King County iMap (Appendix B, Figure B.5). • Basin Plan: Big Soos Creek according to King County GIS iMap, see Figure B.6 in Appendix B. • The USDA web soil survey that shows the downstream area soil information is in Appendix B, Figure B.7. Tasks 3 and 4 A field study of Big Soos Creek extending one-quarter mile downstream of the Site discharge point (culvert) was attempted in July 2025. Visual observation of Big Soos Creek could not be made due to the wetland and heavy vegetation restricting accessibility 7 to Big Soos Creek. See photos attached to Off-site Analysis Drainage System Table. As an alternative to a field study, several different resources (topographic survey, GIS maps) have been acquired to support Tasks 3 and 4. Topographic survey indicates Big Soos Creek enters a 60-inch diameter culvert that lies under SE 192nd Street. This is point ‘A’ shown on the Off-site Analysis Drainage System Table (Table) in Appendix B. Point B is the downstream end of the 60-inch diameter culvert where flow exits the culvert and re- enters the natural stream of Big Soos Creek. According to GIS maps, Big Soos Creek traverses southerly via a meandering course. At approximately 500 feet downstream from point B, the stream reaches a location close to the existing elevated boardwalk trail (Point ‘C’) according to GIS maps. However, due to heavy vegetation the stream was not visible (photos 3 and 4). The stream continues south in close proximity to the boardwalk trail for another 300 feet before it turns east then south to reach the ¼-mile limit of the downstream analysis. No downstream conditions that may be adversely affected by the project have been identified or anticipated. SECTION - 4 FLOW CONTROL, LOW IMPACT DEVELOPMENT (LID) AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Part A - Existing Site Hydrology The Site consists of three King County Parks parcels (parcel # 332305-9057 a.k.a. Boulevard Lane Park, parcel # 332305-9010, and parcel # 332305-9073) and one Tract (parcel # 133273-0840) which are situated between SE 192nd Street and SE 186th Street. The total area of these parcels is 1,045,774 square feet or 24.00 acres. The Site is mostly flat and some uplands with its landscape dominated by Big Soos Creek and adjacent wetland along the eastern and middle part. The western part of the site is upland where the Project Site is situated. A portion on the eastern part of Boulevard Lane Park parcel (9057) was developed as a local community park. A southwest portion of the same parcel was developed by the adjacent Canyon Terrace subdivision. The northeastern part of parcel (9073) was developed for King County Parks maintenance facilities. The site is also a corridor of the overhead BPA transmission power lines where only low-growing vegetation exists. The community park, maintenance facility and the vegetation along the BPA line corridor are considered native pasture for stormwater management and modeling purposes. The COR Flow Control Map indicates the site is within the Duration Flow Control Standard - Forested Conditions area. See Exhibit 1 for a summary of existing site hydrology. See Table 4.1 below for the site pre-developed land use conditions. The pre- developed condition for the Project Site flow control is the historic site condition. One hundred percent (100%) forest cover land use is modeled in WWHM12. Pre-developed Site Conditions Land Use Parcel No. Forest, ac. Wetland, ac. Pasture, ac Parcel, ac. 8 332305-9057 0.78 14.72 1.33 16.83 332305-9010 0.00 0.34 1.58 1.92 332305-9073 0.00 1.07 3.45 4.52 133273-0840 0.73 0.00 0.00 0.73 Site Total 1.51 16.13 6.36 24.00 Table 4.1 The upland forested area (Alderwood soil) and lowland wetland area (Norma soil) are in the Till soil group for continuous modeling. Part B - Developed Site Hydrology The proposed trail Project Site will traverse from SE 192nd Street at the southern end to SE 186th Street at the northern end. The first 80 feet of the proposed trail improvements is elevated boardwalk over wetland. At approximate trail station 11+10 where the trail transition from elevated boardwalk to at-grade as the trail leaves the wetland, from which the proposed trail segment traverses westerly along SE 192nd Street then turns northward along a cleared upland corridor adjacent to the Canyon Terrace subdivision development. From approximately station 16+60, the proposed trail then traverses through an undeveloped Tract and then along the BPA power transmission lines corridor. Note that the east-west direction trail portion along SE 192nd Street is located in unincorporated KC and KC Roads right-of-way. Also located in KC jurisdiction of the Project Site is the proposed sidewalk connecting the trail to Meeker Middle School. Offsite runoff from higher ground development to the west currently flows to this undeveloped upland area and ultimately discharges to the wetland and Big Soos Creek. The offsite runoff discharge pattern is not altered by the trail development. The trail development will include various proposed measures such as sheet flow, dispersion trenches, rock pads, permeable railroad ballast trail bed to maintain and not alter the flow characteristics. The proposed clearing/land disturbed area is considered the Project Site of which 1.70 acres of pre-developed forest and pasture land use is converted to impervious surface and mitigation planting (pervious) area. All runoff from the target surface area will be dispersed into the adjacent vegetated area to the east . Summary of the developed Site hydrology and Project Site is shown in Table 4.2 below: Developed Conditions Land Use Total Site, acres Forest, ac. (Undisturbed) Wetland, ac. (Undisturbed) Pasture, ac. (Undisturbed) Impervious, acres Pervious, acres 24.00 1.03 16.13 5.14 0.79 0.91 Developed Project Site Land Use Project Site, acres Forest, ac. Wetland, ac. Pasture, ac. Impervious, acres Pervious, acres 1.70 0.00 None None 0.79 0.91 Table 4.2 9 WWHM12 analyses for predeveloped and developed conditions are included in Appendix E. Runoff from the trail will be managed using Full Dispersion, using sheet flow dispersion over most of the trail alignment (approximately station 12+00 to station 30+50), and dispersion trenches in the northern part of the trail (approximately station 30+50 to station 33+00) where basic dispersion is implemented. The developed area to have full dispersion is modeled as forest condition. The developed area to have basic dispersion is modeled as 90% impervious and 10% grass (City Drainage Manual Table 1.2.9.A). These equate to the developed Project Site being modeled as 1.59 acres of forest, 0.10 acres of impervious surface, and 0.01 acres of grass. Based on WWHM12 modeled results, flow control facilities are not required as the project generates an increase of less than 0.15 cfs of the 100-year peak runoff, meeting the Exception 3 conditions of section 1.2.3.1, Part B of the SWDM. Note that full dispersion typically requires a 100-foot native vegetated flow path located entirely between the trail and the wetland. However, Section C.2.1.2 of the City Drainage Manual, Delineation of Native Vegetated Area for Full Dispersion, indicates that the native vegetated flow path must be delineated on the site plans as a “native growth retention area.” Section C.2.1.2.2 further indicates that this “native growth retention area may include any unsubmerged critical areas and any critical area buffers.” “Unsubmerged” is defined as outside the ordinary highwater mark (OHWM) of streams, lakes and wetlands. A separate Application for Drainage Criteria Standard Adjustment dated 9/4/2025 is submitted to supplement this report to allow portion of the 100-ft minimum full dispersion flow path to occur across wetland located between the non-wetland/non-disturbed area and Big Soos Creek. The Drainage Adjustment also applies for a waiver from the requirement to perform field delineation of Big Soos Creek OHWM. Based on this and because Section C.2.1.2.4 states that the native growth retention area “may be used for … pedestrian and bicycle use,” an allowed native vegetation flow path of at least 100 feet exists along the entire trail alignment. With full dispersion being feasible pending the City approval of Drainage Adjustment application, flow control facilities are not required. Appropriate native vegetation retention areas are shown on the site plans. Part C – Performance Standards As described in Part A above, duration-forest flow control standard applies to the site. This standard is met by applying full dispersion to all target surfaces. Water quality treatment standard is not reported because the proposed trail will not add pollution generating surfaces. Part D – Flow Control System As described in Part B above, most of the proposed trail will implement full dispersion by either sheet flow or dispersion trench. The project site is exempt from needing flow control facilities as explained in Part B above. Part E – Water Quality System 10 As described in Part B, water quality treatment is not required for this project. This section therefore addresses flow control design only. SECTION 5 - CONVEYANCE SYSTEM ANALYSIS AND DESIGN The majority of the proposed trail drainage is sheet flow with the exception of the northern portion of the trail. Runoff from this northern trail portion is collected by grass swales and conveyed to a dispersion trench via catch basin and pipe. The Rational Method was used to compute the 25-year peak runoff rate from the northern trail segment to be 0.42 cfs. Rational Method calculations are included in Appendix D. A 12-inch diameter pipe at a slope of 0.005 ft/ft, with a roughness factor of 0.012 are modeled to verify flow capacity. FlowMaster worksheets (included in Appendix D) show that the flow rate of a half-full 12-inch plastic circular pipe at a minimum slope of 0.005 ft/ft and roughness 0.012 is 1.36 cfs, exceeding the 25-year peak flow of 0.42 cfs. SECTION 6 - SPECIAL REPORTS AND STUDIES Wetland delineation was performed as part of the design. The wetland boundary and buffer were delineated on the project site and outside the project limits. The project Wetland and Stream Delineation Report dated 3/6/2025 prepared by Facet (formerly DCG/Watershed) is submitted separately to COR. The Wetland and Stream Delineation Report provides explanation for the Ordinary high water mark (OHWM) of Big Soos Creek being not feasible to be delineated. SECTION 7 - OTHER PERMITS No additional permits have been identified. SECTION 8 - CSWPP PLAN ANALYSIS AND DESIGN Part A - ESC Plan Analysis and Design Site soils, slopes and observed site conditions indicate that the risk of erosion during construction is low. Well established existing and native vegetation that will be left undisturbed will act as a filter strip and protect the adjacent wetland and stream from erosion that might occur. The Temporary Erosion and Sediment Control Plan was developed based on these observations and consideration of the following minimum measures: 1. Clearing limits Clearing limits are shown in the Plans and will be staked in the field. 11 2. Cover measures Cover measures will be employed for all soil and material stockpiles that are potential sources of pollutants in stormwater runoff. 3. Perimeter protection A silt fence will be used around the perimeter of the site, as shown on the plans. 4. Construction entrance stabilization The construction ingress/egress point will be stabilized temporarily using a construction entrance, until such time as it will be paved as the parking lot driveway. 5. Sediment retention Temporary sediment traps will be provided as necessary based on site conditions. They are unlikely to be needed based on the unconcentrated flow conditions. 6. Surface water collection Depending on location, surface water will disperse naturally to the east through native vegetation. 7. Dewatering control Not anticipated to be necessary; no excavations are planned. 8. Dust control Dust control will be provided via water truck, as necessary. 9. Flow control Site runoff during construction will be dispersed as under existing conditions. Part B - SWPPS Plan Design There are two potential sources of stormwater pollution from the site: disturbed soil during grading, and fluids associated with construction equipment. The Stormwater Pollution Prevention and Spill (SWPPS) Plan must contain perimeter control measures (silt fence) and final site stabilization measures (seed and mulch) to address disturbed soils. Construction equipment pollutants, such as fuel, hydraulic fluids, and coolants must be controlled through appropriate storage, inspection, maintenance and spill control BMPs identified in the CSWPPS Plan to be prepared by the contractor. The project site discharges through native vegetation to a wetland on the east. This wetland eventually leads to the Big Soos Creek that flows south to the point of discharge of the site. There are no surface water quality impairments in the vicinity of the site, based on review of the current state Clean Water Act 303d listing of impaired surface water bodies. 12 SECTION 9 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Bond Quantity Worksheet and a Declaration of Covenant for Inspection and Maintenance of Stormwater Facilities and BMPs are required for this project, and are provided with the permit submittal under separate cover. SECTION 10 OPERATION AND MAINTENANCE MANUAL See Appendix F for maintenance requirements for the following facilities to be installed at the site: • Catch basins • Conveyance pipes and ditches • Dispersion trenches. REFERENCES City of Renton Surface Water Design Manual 2022 City of Renton GIS Maps King County GIS iMap NRCS Web Soil Survey, http://websoilsurvey.nrcs.usda.gov/app/WebSoilSurvey.aspx, EXHIBITS SE 186TH ST SE 192ND ST 12 4 T H A V E S E MEEKER MIDDLE SCHOOL 7941230280 0422059024 7932000043 6199600180 6199600160 6199000262 13 3 2 7 3 0 8 4 0 3323059039 0305500310 3323059041 0984100380 0984100370 3323059054 09 8 4 0 0 0 5 1 0 09 8 4 0 0 0 5 2 0 0984000560 0984000470 0422059139 04 2 2 0 5 9 1 6 2 3323059098 SE 188TH ST BOULEVARD LANE PARK 3323059073 3323059010 3323059057 SCALE: 1" = 200' 0 100 200 400 OFSHEET HZ PROJECT NO.: ISSUE DATE: DRAWN BY: REVIEWED BY: APPROVED BY: MGOPALANI 08/12/2025 10:37AM J:\R150278.53 - SOOS CREEK AMD 25\10 CADD & BIM\10.1 AUTOCAD\EXHIBITS\TIR\EXISTING LAND USE.DWG www.huitt-zollars.com EXISTING LAND USE CONDITIONS 1 4 R150278.53 August 29, 2025 M. GOPALANI C. MANNING V. LYSOOS CREEK TRAIL PHASE 5A KING COUNTY PARKS EXHIBIT 1 CITY OF RENTON, WASHINGTON 1700 7TH AVE, SUITE 2075 SEATTLE, WA 98101 206-324-5500 LAND USE AREA FOREST WETLANDS PASTURE ± 1.51 AC ± 16.13 AC ± 6.36 AC TOTAL 24 AC WLWL WL WL WL W L WL WL WL WL WL WL WL WL WL WL WL WL WL 1 3 3 2 7 3 0 8 4 0 3323059010 3323059057 3323059073 APPROX. BIG SOOS CREEK PER C.O.R. GIS MAP WETLAND BOUNDARY KING COUNTY PARKS PROPERTY LINE SCALE: 1" = 200' 0 100 200 400 60" CMP CULVERT OFSHEET HZ PROJECT NO.: ISSUE DATE: DRAWN BY: REVIEWED BY: APPROVED BY: EWORTHY 10/10/2025 12:00PM J:\R150278.53 - SOOS CREEK AMD 25\10 CADD & BIM\10.1 AUTOCAD\EXHIBITS\TIR\EXISTING SITE - EXHIBIT TWO.DWG www.huitt-zollars.com N 2 4 R150278.53 October 10, 2025 E. WORTHY C. MANNING V. LYSOOS CREEK TRAIL PHASE 5A KING COUNTY PARKS EXHIBIT 2 CITY OF RENTON 1700 7th Avenue, Suite 2075 Seattle, Washington 98101-1360 206.324.5500 SE 192ND ST SE 18 6 T H S T MEEKER MIDDLE SCHOOL 12 4 T H A V E S E SE 188TH PL BOULEVARD LANE PARK E;ISTIN* SITE 'RAINA*E &ON'ITIO 3323059057 3323059073 33 2 3 0 5 9 0 1 0 13 3 2 7 3 0 8 4 0 SCALE: 1" = 200' 0 100 200 400 OFSHEET HZ PROJECT NO.: ISSUE DATE: DRAWN BY: REVIEWED BY: APPROVED BY: MGOPALANI 08/12/2025 10:36AM J:\R150278.53 - SOOS CREEK AMD 25\10 CADD & BIM\10.1 AUTOCAD\EXHIBITS\TIR\PROPOSED SITE CONDITIONS.DWG www.huitt-zollars.com PROPOSED LAND USE CONDITIONS 3 4 R150278.53 August 29, 2025 M. GOPALANI C. MANNING V. LYSOOS CREEK TRAIL PHASE 5A KING COUNTY PARKS EXHIBIT 3 CITY OF RENTON, WASHINGTON 1700 7th Avenue, Suite 2075 Seattle,Washington 98101-1360 206.324.5500 PROPOSED SOOS CREEK TRAIL LAND USE AREA FOREST/ UNDISTURBED WETLANDS/ UNDISTURBED IMPERVIOUS/ NEW ± 1.03 AC ± 16.13 AC ± 0.79 AC TOTAL 24.00 AC PERVIOUS/ NEW ± 0.91 AC PASTURE/ UNDISTURBED ± 5.35 AC SE 192ND ST MEEKER MIDDLE SCHOOL 12 4 T H A V E S E SE 1 8 6 T H S T 1.70 AC DISTURBED AREA MODELED AS 1.59 AC FOREST, 0.10 AC HARD SURFACE, 0.01 AC GRASS WLWL WL WL WL W L WL WL WL WL WL WL WL WL WL WL WL WL WL A P N 1 3 3 2 7 3 0 8 4 0 APN 3323059039 VV VV VV VV VV VV VV V V VV VV VV APN 3323059073 APN 3323059010 APN 3323059057 APN 3323059057 APN 3323059098 APPROX. BIG SOOS CREEK PER C.O.R. GIS MAP PROPOSED TRAIL WETLAND BOUNDARY KING COUNTY PARKS PROPERTY LINE OFSHEET HZ PROJECT NO.: ISSUE DATE: DRAWN BY: REVIEWED BY: APPROVED BY: RTAM 10/08/2025 10:27AM C:\USERS\RTAM\APPDATA\LOCAL\TEMP\ACPUBLISH_62900\PROPOSED STORM DRAIN SITE PLAN.DWG www.huitt-zollars.com PROPOSED STORM DRAIN SITE PLAN 4 4 R150278.53 August 29, 2025 M. GOPALANI C. MANNING V. LYSOOS CREEK TRAIL PHASE 5A KING COUNTY PARKS EXHIBIT 4 CITY OF RENTON, WASHINGTON 1700 7th Avenue, Suite 2075 Seattle, Washington 98101-1360 206.324.5500 SCALE: 1" = 200' 0 100 200 400 PROPOSED DISPERSION TRENCHES SWALE CATCH BASIN (TYP.) EXISTING CULVERT SE 192ND ST SE 186TH S T SE 188TH PL MEEKER MIDDLE SCHOOL 12 4 T H A V E S E BOULEVARD LANE PARK APPROX. 100-YEAR BASE FLOOD ELEV = 374.4 APPROX. 100-YEAR BASE FLOOD ELEV = 374.2 APPROX. 100 YEAR FLOODPLAIN SEE EXHIBIT 4B FIGURES FIGURE 1 - TIR WORKSHEETSee Appendix A SITE EXISTING SOOS CREEK TRAIL FIGURE 2 PROJECT SITE 9,028 752 Subbasin on Renton Side Legend 5120256 Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere All data, information, and maps are provided "as is" without warranty or any representation of accuracy, timeliness of completeness. The burden for determining accuracy, completeness, timeliness, merchantability and fitness for or the appropriateness for use rests solely on the user. City and County Labels Parcels City and County Boundary Renton <all other values> Environment Designations Natural Shoreline High Intensity Shoreline Isolated High Intensity Shoreline Residential Urban Conservancy Jurisdictions Streams (Classified) S - Shoreline F - Fish Np - Non-Fish Ns - Non-Fish Seasonal Unclassfied Wetlands 5' Primary 5' Intermediate Pump Station Public Pump Station Private Pump Station Discharge Point Public Discharge Point FIGURE 3A 0.3 mi0.3 mi 0.5 mi 0.0 mi 0.5 mi 0.4 mi0.4 mi 0.2 mi0.2 mi 0.0 mi0.0 mi 0.1 mi0.1 mi 0.3 mi King County Date: 1/6/2025 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject 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 intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. Subbasin on KC SideFIGURE 3B FIGURE 4 APPENDIX A - TIR WORKSHEET CITY OF RENTON SURFACE WATER DESIGN MANUAL 2022 City of Renton Surface Water Design Manual 6/22/2022 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Land Use (e.g., Subdivision / Short Subd.) Building (e.g., M/F / Commercial / SFR) Grading Right-of-Way Use Other _______________________ DFW HPA COE 404 DOE Dam Safety FEMA Floodplain COE Wetlands Other ________ Shoreline Management Structural Rockery/Vault/_____ ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final: Full Targeted Simplified Large Project Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final: Full Modified Simplified __________________ __________________ __________________ King County Parks Soos Creek Trail Phase 5A Huitt-Zollars 206 324 5500 x X 201 S Jackson St, Room 700 Seattle, WA 98104 Viet Ly 23 N 5 E 33 X REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/Stream ________________________ Lake ______________________________ Wetlands ____________________________ Closed Depression ____________________ Floodplain ___________________________ Other _______________________________ _______________________________ Steep Slope __________________________ Erosion Hazard _______________________ Landslide Hazard ______________________ Coal Mine Hazard ______________________ Seismic Hazard _______________________ Habitat Protection ______________________ _____________________________________ x x None Soos Creek None Big Soos Creek Soos Creek xx Full dispersion criteria adjustment REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________ High Groundwater Table (within 5 feet) Other ________________________________ Sole Source Aquifer Seeps/Springs Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core 2 – Offsite Analysis_________________ Sensitive/Critical Areas__________________ SEPA________________________________ LID Infeasibility________________________ Other________________________________ _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 9 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No 1 0 to 8%Low x x None Infiltration not feasible TBD TDA 1 Alderwood gravelly sandy loam x x stream, wetland None REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ On-site BMPs Describe: Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: None. No pollutant generating target surfaces None NAVD88 374.2 - 375.0 Recreational trail REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Collection Dewatering Control Dust Control Flow Control Control Pollutants Protect Existing and Proposed BMPs/Facilities Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize exposed surfaces Remove and restore Temporary ESC Facilities Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary Flag limits of sensitive areas and open space preservation areas Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Description Water Quality Description On-site BMPs Description Detention Infiltration Regional Facility Shared Facility Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Vegetated Flowpath Wetpool Filtration Oil Control Spill Control Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Full Dispersion Full Infiltration Limited Infiltration Rain Gardens Bioretention Permeable Pavement Basic Dispersion Soil Amendment Perforated Pipe Connection Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ X X X X X X X X X X X X X X X X X X REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-6 Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Covenant Tract Other ____________________________ Cast in Place Vault Retaining Wall Rockery > 4′ High Structural on Steep Slope Other _______________________________ Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date 10/6/2025 APPENDIX B - DOWNSTREAM ANALYSIS SUPPORTING DOCUMENTS 1.0 mi King County Date: 1/6/2025 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject 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 intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. 1 Mile Downstream DISCHARGE LOCATION AT SE 192ND ST CULVERT EXISTING SOOS CREEK TRAIL SE 192ND ST 12 4 T H A V E S E SITE APPROX'LY 1/4 MILES DOWNSTREAM FIGURE B.1 DISCHARGE LOCATION AT SE 192ND ST CULVERT PROJECT SITE EXISTING SOOS CREEK TRAIL +/- 1/4 MILE DOWNTREAM OF DISCHARGE LOCATION FIGURE B.2 9,028 752 Erosion Hazard Legend 5120256 Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere All data, information, and maps are provided "as is" without warranty or any representation of accuracy, timeliness of completeness. The burden for determining accuracy, completeness, timeliness, merchantability and fitness for or the appropriateness for use rests solely on the user. City and County Labels Parcels City and County Boundary Renton <all other values> Erosion Hazard - High Landslide Very High High Moderate Unclassified Environment Designations Natural Shoreline High Intensity Shoreline Isolated High Intensity Shoreline Residential Urban Conservancy Jurisdictions Streets Waterbodies 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 FIGURE B.3 King County Date: 12/26/2024 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject 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 intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. Critical Aquifer Recharge AreaFIGURE B.4 9,028 752 Seismic Hazard Legend 5120256 Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere All data, information, and maps are provided "as is" without warranty or any representation of accuracy, timeliness of completeness. The burden for determining accuracy, completeness, timeliness, merchantability and fitness for or the appropriateness for use rests solely on the user. City and County Labels Parcels City and County Boundary Renton <all other values> Landslide Very High High Moderate Unclassified Environment Designations Natural Shoreline High Intensity Shoreline Isolated High Intensity Shoreline Residential Urban Conservancy Jurisdictions Seismic Hazard Areas Faults Streets Waterbodies 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 FIGURE B.5 King County Date: 3/21/2025 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject 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 intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. Basin Map SITE SOOS CREEK BASIN FIGURE B.6 Soil Map—King County Area, Washington (Downstream Soil Map) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/7/2025 Page 1 of 3 52 5 2 1 0 0 52 5 2 3 0 0 52 5 2 5 0 0 52 5 2 7 0 0 52 5 2 9 0 0 52 5 3 1 0 0 52 5 3 3 0 0 52 5 3 5 0 0 52 5 2 1 0 0 52 5 2 3 0 0 52 5 2 5 0 0 52 5 2 7 0 0 52 5 2 9 0 0 52 5 3 1 0 0 52 5 3 3 0 0 52 5 3 5 0 0 561700 561900 562100 562300 562500 562700 562900 563100 563300 563500 563700 563900 561700 561900 562100 562300 562500 562700 562900 563100 563300 563500 563700 563900 47° 25' 56'' N 12 2 ° 1 1 ' 1 ' ' W 47° 25' 56'' N 12 2 ° 9 ' 5 ' ' W 47° 25' 5'' N 12 2 ° 1 1 ' 1 ' ' W 47° 25' 5'' N 12 2 ° 9 ' 5 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 500 1000 2000 3000 Feet 0 150 300 600 900 Meters Map Scale: 1:11,000 if printed on A landscape (11" x 8.5") sheet. Soil Map may not be valid at this scale. FIGURE B.7 MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: King County Area, Washington Survey Area Data: Version 20, Aug 27, 2024 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 31, 2022—Aug 8, 2022 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Soil Map—King County Area, Washington (Downstream Soil Map) Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/7/2025 Page 2 of 3 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI AgB Alderwood gravelly sandy loam, 0 to 8 percent slopes 180.0 38.3% AgC Alderwood gravelly sandy loam, 8 to 15 percent slopes 57.3 12.2% AgD Alderwood gravelly sandy loam, 15 to 30 percent slopes 22.9 4.9% AmB Arents, Alderwood material, 0 to 6 percent slopes 13.8 2.9% EvB Everett very gravelly sandy loam, 0 to 8 percent slopes 53.8 11.5% EvC Everett very gravelly sandy loam, 8 to 15 percent slopes 4.2 0.9% InC Indianola loamy sand, 5 to 15 percent slopes 22.0 4.7% No Norma sandy loam 20.1 4.3% PITS Pits 6.7 1.4% Sk Seattle muck 86.5 18.4% W Water 2.5 0.5% Totals for Area of Interest 469.7 100.0% Soil Map—King County Area, Washington Downstream Soil Map Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 1/7/2025 Page 3 of 3 CITY OF RENTON SURFACE WATER DESIGN MANUAL 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-B-1 REFERENCE 8-B OFF-SITE ANALYSIS DRAINAGE SYSTEM TABLE CITY OF RENTON SURFACE WATER DESIGN MANUAL, CORE REQUIREMENT #2 Basin: Subbasin Name: Subbasin Number: Date Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance from Site Discharge Existing Problems Potential Problems Observations of Field Inspector, Resource Reviewer, or Resident See map Type: sheet flow, swale, stream, channel, pipe, pond, flow control/ treatment/on-site BMP/facility Size: diameter, surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % ¼ ml = 1,320 ft. Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion Tributary area, likelihood of problem, overflow pathways, potential impacts A 60-inch pipe culvert 0 ftpipe crosses under S 192nd St less than 1% B End culvert/ back to Natural stream Flow exits culvert and re-enter Big Soos Creek, heavy vegeration 60 ft Pipe is partially under water, slow flow is observed C Big Soos Creek 500 ftBend in stream nearboardwalk trail D Big Soos Creek End of 1/4-mile studylimit, stream continuessouth 1,320 ft DISCHARGE LOCATION AT SE 192ND ST CULVERT PROJECT SITE EXISTING SOOS CREEK TRAIL +/- 1/4 MILE DOWNTREAM OF DISCHARGE LOCATION point 'B' point 'C' point 'D' point 'A' Photo 1 - Upstream End of Culvert (Point 'A') Photo 2 - Downstream End of Culvert (Point 'B') Photo 3 - Big Soos Creek is not visible Photo 4 - Big Soos Creek is not visible APPENDIX C - GEOTECHNICAL REPORT Submitted under separate cover: Draft Geotechnical Engineering Design Report Revision 01, dated August 1, 2025, prepared by Haley Aldrich APPENDIX D - DESIGN CALCULATIONS Soos Creek Pipe Flow Project Description ManningFormulaFriction Method DischargeSolve For Input Data 0.012Roughness Coefficient ft/ft0.005Channel Slope in6.0Normal Depth in12.0Diameter Results cfs1.36Discharge ft²0.4Flow Area ft1.6Wetted Perimeter in3.0Hydraulic Radius ft1.00Top Width in5.9Critical Depth %50.0Percent Full ft/ft0.005Critical Slope ft/s3.47Velocity ft0.19Velocity Head ft0.69Specific Energy 0.978Froude Number cfs2.94Maximum Discharge cfs2.73Discharge Full ft/ft0.001Slope Full SubcriticalFlow Type GVF Input Data in0.0Downstream Depth ft0.0Length 0Number Of Steps GVF Output Data in0.0Upstream Depth N/AProfile Description ft0.00Profile Headloss %0.0Average End Depth Over Rise %0.0Normal Depth Over Rise ft/s0.00Downstream Velocity ft/s0.00Upstream Velocity in6.0Normal Depth in5.9Critical Depth ft/ft0.005Channel Slope ft/ft0.005Critical Slope Page 1 of 127 Siemon Company Drive Suite 200 W Watertown, CT 06795 USA +1-203-755-1666 3/3/2025 FlowMaster [10.03.00.03] Bentley Systems, Inc. Haestad Methods Solution CenterUntitled1.fm8 HYDROLOGY BY RATIONAL FORMULA (English or Metric Units) This spreadsheet calculates runoff rate and volume using the rational method. Enter the data in the grey shaded areas only. Project Name:Soos Creek Trail Phase 5a SR :N/A By:Huitt-Zollars Project Number: Date:Mar. 2025 Q = Flow (cfs or m3/s)Tc = time of concentration (min) L = Length of drainage basin (ft or m)m & n = Rainfall coefficients S = Average slope (ft/ft, m/m) Kc = Conversion factor (1 for English, 360 for Metric) K = Ground cover coeeficient (ft/min or m/min)C = Runoff coefficient I = Rainfall intensity (in/hr or mm/hr)A = Drainage area (acres or ha) Description of Area MRI L S K Tc Rainfall Coefficients Kc C I A Q Trail Station 25-year m n 32+00 to 34+00 200 0.04 1200 0.83 6.89 0.539 1 0.99 2.894 0.065 0.186 Forest Uphill 300 0.10 150 6.32 6.89 0.539 1 0.22 2.550 0.460 0.258 Composite 300 6.32 6.89 0.539 1 0.315 2.550 0.525 0.422 COMPOSITE "C" Calculation SUBBASIN C Area, Ac C*A Hard Surface 0.99 0.065 0.06435 Forest 0.22 0.46 0.1012 SUM A 0.525 SUM(D45,D47,D49) SUM C*A 0.166 SUM(E45,E47,E49) Comp C 0.315 E53/E52 APPENDIX E – WWHM MODELING WWHM2012 PROJECT REPORT DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:40 PM Page 2 General Model Information Project Name:Soos Creek Project Site 2025.0430 Site Name:Soos Creek Trail Site Address: City:Renton Report Date:4/30/2025 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:41 PM Page 3 Landuse Basin Data Predeveloped Land Use Soos Creek Site Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.7 Pervious Total 1.7 Impervious Land Use acre Impervious Total 0 Basin Total 1.7 Element Flows To: Surface Interflow Groundwater DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:41 PM Page 4 Mitigated Land Use Developed Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.59 C, Lawn, Flat 0.01 Pervious Total 1.6 Impervious Land Use acre ROADS FLAT 0.1 Impervious Total 0.1 Basin Total 1.7 Element Flows To: Surface Interflow Groundwater DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:41 PM Page 5 Routing Elements Predeveloped Routing DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:41 PM Page 6 Mitigated Routing DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:44:41 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.7 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.6 Total Impervious Area:0.1 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.049981 5 year 0.078498 10 year 0.094658 25 year 0.111779 50 year 0.122374 100 year 0.131385 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.071975 5 year 0.104395 10 year 0.127842 25 year 0.159681 50 year 0.184995 100 year 0.211675 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.049 0.096 1950 0.061 0.097 1951 0.110 0.123 1952 0.035 0.054 1953 0.028 0.042 1954 0.043 0.056 1955 0.069 0.083 1956 0.055 0.077 1957 0.044 0.079 1958 0.050 0.063 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:15 PM Page 8 1959 0.043 0.054 1960 0.074 0.102 1961 0.042 0.063 1962 0.026 0.038 1963 0.036 0.058 1964 0.047 0.067 1965 0.034 0.065 1966 0.032 0.053 1967 0.068 0.106 1968 0.042 0.070 1969 0.041 0.067 1970 0.034 0.063 1971 0.037 0.070 1972 0.082 0.098 1973 0.037 0.051 1974 0.040 0.066 1975 0.055 0.091 1976 0.040 0.066 1977 0.005 0.033 1978 0.035 0.054 1979 0.021 0.055 1980 0.078 0.121 1981 0.031 0.056 1982 0.060 0.111 1983 0.054 0.069 1984 0.033 0.050 1985 0.020 0.041 1986 0.087 0.101 1987 0.077 0.102 1988 0.030 0.041 1989 0.020 0.040 1990 0.160 0.222 1991 0.096 0.137 1992 0.037 0.061 1993 0.039 0.051 1994 0.013 0.027 1995 0.056 0.069 1996 0.117 0.145 1997 0.098 0.115 1998 0.022 0.051 1999 0.092 0.135 2000 0.039 0.062 2001 0.007 0.043 2002 0.042 0.068 2003 0.054 0.089 2004 0.070 0.102 2005 0.050 0.080 2006 0.059 0.079 2007 0.119 0.173 2008 0.153 0.187 2009 0.075 0.108 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1602 0.2216 2 0.1534 0.1867 3 0.1189 0.1728 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:15 PM Page 9 4 0.1171 0.1446 5 0.1101 0.1369 6 0.0979 0.1352 7 0.0965 0.1232 8 0.0918 0.1213 9 0.0866 0.1151 10 0.0820 0.1111 11 0.0777 0.1084 12 0.0766 0.1057 13 0.0753 0.1023 14 0.0744 0.1020 15 0.0700 0.1017 16 0.0687 0.1013 17 0.0680 0.0976 18 0.0612 0.0969 19 0.0597 0.0960 20 0.0592 0.0915 21 0.0556 0.0892 22 0.0548 0.0826 23 0.0547 0.0796 24 0.0540 0.0792 25 0.0535 0.0788 26 0.0502 0.0774 27 0.0497 0.0701 28 0.0491 0.0699 29 0.0472 0.0693 30 0.0441 0.0691 31 0.0431 0.0680 32 0.0426 0.0668 33 0.0424 0.0667 34 0.0423 0.0665 35 0.0420 0.0660 36 0.0415 0.0649 37 0.0404 0.0632 38 0.0396 0.0628 39 0.0388 0.0628 40 0.0386 0.0621 41 0.0372 0.0608 42 0.0372 0.0579 43 0.0366 0.0563 44 0.0359 0.0557 45 0.0347 0.0546 46 0.0347 0.0542 47 0.0342 0.0541 48 0.0338 0.0540 49 0.0330 0.0527 50 0.0325 0.0512 51 0.0310 0.0511 52 0.0302 0.0508 53 0.0281 0.0498 54 0.0261 0.0426 55 0.0221 0.0421 56 0.0210 0.0415 57 0.0197 0.0415 58 0.0196 0.0404 59 0.0130 0.0377 60 0.0069 0.0333 61 0.0047 0.0269 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:16 PM Page 10 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:16 PM Page 11 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0250 17547 21988 125 Fail 0.0260 16164 20129 124 Fail 0.0270 14972 18465 123 Fail 0.0279 13851 17017 122 Fail 0.0289 12816 15727 122 Fail 0.0299 11813 14484 122 Fail 0.0309 10900 13374 122 Fail 0.0319 10121 12414 122 Fail 0.0329 9390 11541 122 Fail 0.0338 8731 10752 123 Fail 0.0348 8147 10016 122 Fail 0.0358 7593 9311 122 Fail 0.0368 7060 8701 123 Fail 0.0378 6590 8132 123 Fail 0.0388 6145 7608 123 Fail 0.0397 5777 7127 123 Fail 0.0407 5433 6671 122 Fail 0.0417 5097 6258 122 Fail 0.0427 4808 5895 122 Fail 0.0437 4522 5559 122 Fail 0.0447 4252 5240 123 Fail 0.0456 4017 4941 123 Fail 0.0466 3782 4629 122 Fail 0.0476 3546 4359 122 Fail 0.0486 3339 4122 123 Fail 0.0496 3138 3906 124 Fail 0.0506 2952 3694 125 Fail 0.0515 2787 3471 124 Fail 0.0525 2599 3279 126 Fail 0.0535 2447 3114 127 Fail 0.0545 2304 2930 127 Fail 0.0555 2160 2776 128 Fail 0.0565 2026 2605 128 Fail 0.0575 1898 2425 127 Fail 0.0584 1790 2297 128 Fail 0.0594 1688 2182 129 Fail 0.0604 1584 2075 130 Fail 0.0614 1483 1955 131 Fail 0.0624 1379 1849 134 Fail 0.0634 1292 1749 135 Fail 0.0643 1219 1647 135 Fail 0.0653 1154 1553 134 Fail 0.0663 1098 1452 132 Fail 0.0673 1048 1364 130 Fail 0.0683 997 1279 128 Fail 0.0693 930 1210 130 Fail 0.0702 883 1142 129 Fail 0.0712 837 1091 130 Fail 0.0722 789 1039 131 Fail 0.0732 743 984 132 Fail 0.0742 713 938 131 Fail 0.0752 668 898 134 Fail 0.0761 630 858 136 Fail 0.0771 595 819 137 Fail Note that no flow control/detentionis modeled because full dispersionis applied DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:16 PM Page 12 0.0781 565 774 136 Fail 0.0791 539 738 136 Fail 0.0801 496 698 140 Fail 0.0811 473 652 137 Fail 0.0820 434 618 142 Fail 0.0830 399 591 148 Fail 0.0840 366 561 153 Fail 0.0850 348 531 152 Fail 0.0860 323 503 155 Fail 0.0870 296 474 160 Fail 0.0879 272 449 165 Fail 0.0889 256 432 168 Fail 0.0899 235 398 169 Fail 0.0909 217 375 172 Fail 0.0919 195 339 173 Fail 0.0929 180 312 173 Fail 0.0938 158 291 184 Fail 0.0948 145 266 183 Fail 0.0958 129 246 190 Fail 0.0968 119 221 185 Fail 0.0978 109 201 184 Fail 0.0988 97 191 196 Fail 0.0997 91 174 191 Fail 0.1007 82 161 196 Fail 0.1017 76 147 193 Fail 0.1027 68 138 202 Fail 0.1037 62 127 204 Fail 0.1047 55 121 220 Fail 0.1057 48 114 237 Fail 0.1066 41 110 268 Fail 0.1076 38 103 271 Fail 0.1086 33 96 290 Fail 0.1096 27 92 340 Fail 0.1106 22 88 400 Fail 0.1116 21 79 376 Fail 0.1125 20 73 365 Fail 0.1135 19 63 331 Fail 0.1145 17 59 347 Fail 0.1155 14 54 385 Fail 0.1165 12 49 408 Fail 0.1175 9 41 455 Fail 0.1184 4 38 950 Fail 0.1194 3 35 1166 Fail 0.1204 3 34 1133 Fail 0.1214 3 31 1033 Fail 0.1224 3 27 900 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. DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:16 PM Page 13 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. DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:16 PM Page 14 LID Report DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:40 PM Page 15 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:40 PM Page 16 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. DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:40 PM Page 17 Appendix Predeveloped Schematic DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:44 PM Page 18 Mitigated Schematic DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 19 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 Soos Creek Project Site 2025.0430.wdm MESSU 25 PreSoos Creek Project Site 2025.0430.MES 27 PreSoos Creek Project Site 2025.0430.L61 28 PreSoos Creek Project Site 2025.0430.L62 30 POCSoos Creek Project Site 2025.04301.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 Soos Creek Site 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 20 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 21 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Soos Creek Site*** PERLND 10 1.7 COPY 501 12 PERLND 10 1.7 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 22 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 23 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 Soos Creek Project Site 2025.0430.wdm MESSU 25 MitSoos Creek Project Site 2025.0430.MES 27 MitSoos Creek Project Site 2025.0430.L61 28 MitSoos Creek Project Site 2025.0430.L62 30 POCSoos Creek Project Site 2025.04301.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Developed 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 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 *** 10 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 24 # - # 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 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 *** 10 0 0 0 0 0 0 0 0 0 0 0 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 10 0 4.5 0.08 400 0.05 0.5 0.996 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 10 0 0 2 2 0 0 0 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 *** 10 0.2 0.5 0.35 6 0.5 0.7 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 10 0 0 0 0 2.5 1 0 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 DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 25 <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# *** Developed*** PERLND 10 1.59 COPY 501 12 PERLND 10 1.59 COPY 501 13 PERLND 16 0.01 COPY 501 12 PERLND 16 0.01 COPY 501 13 IMPLND 1 0.1 COPY 501 15 ******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 *** DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 26 <------><--------><--------><--------><--------><--------><--------> *** 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 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 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 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 END MASS-LINK END RUN DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 27 Predeveloped HSPF Message File DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 28 Mitigated HSPF Message File DR A F T Soos Creek Project Site 2025.0430 4/30/2025 12:45:48 PM Page 29 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. 2005-2025; 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 APPENDIX F - OPERATION AND MAINTENANCE MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-10 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the catch basin to the invert of the lowest pipe into or out of the catch basin or is within 6 inches of the invert of the lowest pipe into or out of the catch basin. Sump of catch basin contains no sediment. Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the catch basin opening or is blocking capacity of the catch basin by more than 10%. No Trash or debris blocking or potentially blocking entrance to catch basin. Trash or debris in the catch basin that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the catch basin. Dead animals or vegetation that could generate odors that could cause complaints or dangerous gases (e.g., methane). No dead animals or vegetation present within catch basin. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering catch basin through cracks, or maintenance person judges that catch basin is unsound. Catch basin is sealed and is structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering catch basin through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Catch basin has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the catch basin at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-11 NO. 5 – CATCH BASINS AND MANHOLES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Inlet/Outlet Pipe (cont.) Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (Catch Basins) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. Damaged or missing grate Grate missing or broken member(s) of the grate. Any open structure requires urgent maintenance. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-38 NO. 25 – DRYWELL BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Plugging, obstructions Any cause limiting flow into drywell. Drywell able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the drywell is evident. No trash or debris that could get into the drywell can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipe Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet. Structure Basin leaks Holes or breaks in the basin allow water to leave the basin at locations other than per design. Basin is sealed and allows water to exit only where designed. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal. NO. 26 – GRAVEL FILLED INFILTRATION TRENCH BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow to infiltration trench. Infiltration trench able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the infiltration trench is evident. No trash or debris that could get into the infiltration trench can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipes Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet to the trench. Structure Flow not reaching trench Flows are not getting into the trench as designed. Water enters and exits trench as designed. Cleanout/inspection access does not allow cleaning or inspection of trench The cleanout/inspection access is not available. Cleanout/inspection access is available. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-39 NO. 27 – GRAVEL FILLED DISPERSION TRENCH BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow to dispersion trench or preventing spreader function. Dispersion trench able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the dispersion trench is evident. No trash or debris that could get into the dispersion trench can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipe Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks. Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet to the trench. Broken or missing cleanout caps Cleanout caps are broken, missing, or buried. Cleanout caps are accessible and intact. Structure Flow not reaching trench Flows are not getting into the trench as designed. Water enters and exits trench as designed. Perforated pipe plugged Flow not able to enter or properly exit from perforated pipe. Water freely enters and exits perforated pipe. Flow not spreading evenly at outlet of trench Outlet flows channelizing or not spreading evenly from trench. Sheet flow occurs at the outlet of the trench. Cleanout/inspection access does not allow cleaning or inspection of perforated pipe The cleanout/inspection access is not available. Cleanout/inspection access is available. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-12 NO. 6 – CONVEYANCE PIPES AND DITCHES MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Pipes Sediment & debris accumulation Accumulated sediment or debris that exceeds 20% of the diameter of the pipe. Water flows freely through pipes. Vegetation/root growth in pipe Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Damage to protective coating or corrosion Protective coating is damaged; rust or corrosion is weakening the structural integrity of any part of pipe. Pipe repaired or replaced. Damaged pipes Any dent that decreases the cross section area of pipe by more than 20% or is determined to have weakened structural integrity of the pipe. Pipe repaired or replaced. Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 square feet of ditch and slopes. Trash and debris cleared from ditches. Sediment accumulation Accumulated sediment that exceeds 20% of the design depth. Ditch cleaned/flushed of all sediment and debris so that it matches design. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive vegetation growth Vegetation that reduces free movement of water through ditches. Water flows freely through ditches. Erosion damage to slopes Any erosion observed on a ditch slope. Slopes are not eroding. Rock lining out of place or missing (If applicable) One layer or less of rock exists above native soil area 5 square feet or more, any exposed native soil. Replace rocks to design standards. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-39 NO. 27 – GRAVEL FILLED DISPERSION TRENCH BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow to dispersion trench or preventing spreader function. Dispersion trench able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the dispersion trench is evident. No trash or debris that could get into the dispersion trench can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipe Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks. Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet to the trench. Broken or missing cleanout caps Cleanout caps are broken, missing, or buried. Cleanout caps are accessible and intact. Structure Flow not reaching trench Flows are not getting into the trench as designed. Water enters and exits trench as designed. Perforated pipe plugged Flow not able to enter or properly exit from perforated pipe. Water freely enters and exits perforated pipe. Flow not spreading evenly at outlet of trench Outlet flows channelizing or not spreading evenly from trench. Sheet flow occurs at the outlet of the trench. Cleanout/inspection access does not allow cleaning or inspection of perforated pipe The cleanout/inspection access is not available. Cleanout/inspection access is available. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal.