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Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Technical Information Report PREPARED FOR: BRIC Architecture Inc. 1233 NW Northrup Street, Suite 100 Portland, OR 97209 PROJECT: New Renton High School 400 South 2nd Street Renton, WA 98057 Project No. 2230388.10 PREPARED BY: Brian Schend, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: September 2025 Revised January 2026 Revised April 2026 Revised June 2026 Technical Information Report PREPARED FOR: BRIC Architecture Inc. 1233 NW Northrup Street, Suite 100 Portland, OR 97209 PROJECT: New Renton High School 400 South 2nd Street Renton, WA 98057 Project No. 2230388.10 PREPARED BY: Brian Schend, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: September 2025 Revised January 2026 Revised April 2026 Revised June 2026 I hereby state that this Technical Information Report for the New Renton High School project has been prepared by me or under my supervision and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Renton does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. 06/10/2026 Technical Information Report New Renton High School Project No. 2230388.10 Table of Contents Section Page 1.0 Project Overview ............................................................................................................................ 1 1.1 Project Phasing ................................................................................................................... 3 2.0 Conditions and Requirements Summary .................................................................................... 4 2.1 CR 1 – Discharge at the Natural Location .......................................................................... 4 2.2 CR 2 – Offsite Analysis ....................................................................................................... 4 2.3 CR 3 – Flow Control ............................................................................................................ 4 2.4 CR 4 – Conveyance System ............................................................................................... 5 2.5 CR 5 – Erosion and Sediment Control ................................................................................ 5 2.6 CR 6 – Maintenance and Operations.................................................................................. 5 2.7 CR 7 – Financial Guarantees and Liability ......................................................................... 5 2.8 CR 8 – Water Quality .......................................................................................................... 5 2.9 CR 9 – Onsite BMPs ........................................................................................................... 5 2.10 SR 1 – Other Adopted Requirements ................................................................................. 5 2.11 SR 2 – Flood Hazard Delineation ....................................................................................... 5 2.12 SR 3 – Flood Protection Facilities ....................................................................................... 6 2.13 SR 4 – Source Control ........................................................................................................ 6 2.14 SR 5 – Oil Control ............................................................................................................... 6 2.15 SR 6 – Aquifer Protection Area ........................................................................................... 6 3.0 Offsite Analysis .............................................................................................................................. 6 3.1 Task 1 – Study Area Definition and Maps........................................................................... 6 3.2 Task 2 – Resource Review ................................................................................................. 8 3.3 Task 3 – Field Inspection .................................................................................................... 8 3.4 Task 4 – Drainage System Description and Problem Descriptions .................................... 9 4.0 Flow Control, Low Impact Development (LID), and Water Quality Facility Analysis and Design ............................................................................................................................................. 9 4.1 Existing Site Hydrology ....................................................................................................... 9 4.1.1 TDA 1 (Black River) ............................................................................................... 9 4.1.2 TDA 2 (Black River) ............................................................................................. 10 4.1.3 TDA 3 (Cedar River) ............................................................................................ 10 4.2 Developed Site Hydrology ................................................................................................ 10 4.2.1 TDA 1 (Black River) ............................................................................................. 10 4.2.2 TDA 2 (Black River) ............................................................................................. 10 Technical Information Report New Renton High School Project No. 2230388.10 4.2.3 TDA 3 (Cedar River) ............................................................................................ 10 4.3 Performance Standards .................................................................................................... 11 4.4 Flow Control System ......................................................................................................... 11 4.5 Water Quality System ....................................................................................................... 11 4.6 Onsite BMPs ..................................................................................................................... 12 5.0 Conveyance System Analysis and Design ................................................................................ 14 6.0 Special Reports and Studies ...................................................................................................... 14 7.0 Other Permits ............................................................................................................................... 15 8.0 Stormwater Pollution Prevention and Spill Plan (SWPPS) Analysis and Design ................. 15 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant ..................................... 15 10.0 Operations and Maintenance Manual ........................................................................................ 16 11.0 Conclusion .................................................................................................................................... 16 Technical Information Report New Renton High School Project No. 2230388.10 Appendices Appendix A Exhibits A-1 ............Technical Information Report Worksheet A-2 ............Vicinity Map A-3 ............Existing Basins Map A-4 ............NRCS Soils Map A-5 ............Floodplain Map A-6 ............Aquifer Protection Map A-7 ............Downstream Drainage Map A-8 ............Landslide Hazard Map A-9 ............Coal Mine Hazard Map A-10 ..........Erosion Hazard Map A-11 ..........Steep Slopes Map A-12 ..........Proposed Basin Map A-13 ..........Water Quality Areas A-14 ..........Water Quality Basins Appendix B Geotechnical Report B-1 ............Geotechnical Engineering Report dated September 3, 2025 B-2 ............Geotechnical Letter dated January 9, 2026 Appendix C Flow Control Calculations Appendix D Water Quality Calculations Appendix E Conveyance Calculations E-1 ............Phase 1 Conveyance E-2 ............Phase 2 Conveyance (to be included in a future submittal) Appendix F Stormwater Pollution Prevention and Spill Plan Appendix G Bonds and Covenants G-1 ............Bond Quantity Worksheet Phase 1 G-2 ............Bond Quantity Worksheet Phase 2 Appendix H Operations and Maintenance Manual Technical Information Report 1 New Renton High School Project No. 2230388.10 1.0 Project Overview The Renton School District (RSD) proposes to construct a new Renton High School at 400 South 2nd Street in Renton, Washington. The project consists of a new school building, parking lots, bus and parent drop-off and pick-up areas, outdoor landscape areas, and sports field, as well as utility and site improvements. The project will be constructed in two phases, as described in Section 1.1 below. Appendix A-1 is a Technical Information Report Worksheet that summarizes the project and Appendix A-2 shows the project location. The project site encompasses 43 tax parcels, which are listed in Table 4 below, and is bounded by Airport Way to the north, Logan Avenue South to the east, North 2nd Street to the south, and Lake Avenue South and Shattuck Avenue South to the west. The existing Renton High School building and associated paved parking, drive lanes, and field are located on Parcel 0007200060. The school district will purchase 42 additional parcels and will vacate portions of South Tobin Street and South Tillicum Street to allow construction of the project. Existing improvements include the high school and its associated parking areas and play fields, as well as existing residences and commercial and light industrial properties. The original high school building from the 1930s and the IKEA Performing Arts Center (IPAC) from the 1990s will remain, while the portions constructed in the 1960s will be demolished. The project will be phased to allow the 1960s portion of the building to remain while the new building is constructed. The residential, commercial, and light industrial properties will be demolished in their entirety. Existing sidewalks and curb and gutter are located along most of the adjacent roadways within the public right-of-way. Airport Way will see new sidewalks, but the existing curb and gutter will remain. Lake Ave S will see new sidewalks along the project frontage as well as extending south to S 2nd St. Logan Ave S and Shattuck Ave S will see new curb, gutter, and sidewalk on the side of the streets facing the school. Improvements on S 2nd St will be limited to new driveways only because City of Renton is planning to improve this street in the near future. The entire pre-dedication site area (all tax parcels) is 35.2 acres. Right-of-way dedications are required along Airport Way, Logan Avenue North, Lake Avenue North, and South Tobin Street. Portions of South Tobin Street and South Tillicum Street will be vacated to construct the project. The entire site area (all tax parcels), including the dedications and vacations, is 33.6 acres. The site has three separate discharge locations and is divided into three threshold discharge areas (TDAs), as mapped on Appendix A-3. The engineered drainage system for the proposed site will not alter existing discharge locations from the site. Runoff from most of the site (TDA 1 and TDA 2) will discharge to Lake Ave N, S 2nd St, or S Tobin St, leading to the Black River. Runoff from the easternmost part of the site (TDA 3) will discharge to Logan Ave S, leading to the Cedar River. Soils for this site are described in a Geotechnical Report attached as Appendix B. Refer to Appendix A-4 for NRCS soil mapping. Table 1: TDA 1 Land Cover Areas Aimp (ac) Aperv (ac) Total (ac) Existing 1.06 0.31 1.37 Proposed 0.68 0.49 1.17 Technical Information Report 2 New Renton High School Project No. 2230388.10 Table 2: TDA 2 Land Cover Areas Aimp (ac) Aperv (ac) Total (ac) Existing 17.88 10.57 28.45 Proposed 19.56 9.23 28.79 Table 3: TDA 3 Land Cover Areas Aimp (ac) Aperv (ac) Total (ac) Existing 4.89 2.08 6.97 Proposed 5.69 1.15 6.84 The proposed project will slightly change the basin boundaries. As a result, the TDA areas between existing and proposed conditions are not exactly the same. Each TDA includes areas in right-of-way, so the total area of all TDAs exceeds the onsite area. Table 4: List of Tax Parcels Parcel Property Address Lot size (SF) Current Use, Built Date Bldg. Size (SF) 1. 722930-0490 301-309 Airport Way 18,000 Warehouse, 1947 26,954 2. 722930-0545 455 Airport Way 34,000 Restaurant, 1949 12,342 3. 722930-0580 511 Airport Way 16,000 Vacant -- 4. 722930-0595 43 Logan Avenue S 4,700 Office, 1956 2,139 5. 722930-0635 51 Logan Avenue S 4,280 SF Home, 1916 6. 722930-0630 55 Logan Avenue S 5,429 SF Home, 1925 1,560 7. 000720-0043 59 Logan Avenue S 5,350 SF Home, 1902 950 8. 000720-0017 75 Logan Avenue S 5,500 SF Home, built 1901 900 9. 000720-0016 81 Logan Avenue S 11,000 SF Home, built 1922 920 10. 569600-0190 97 Logan Avenue S 5,855 SF home, built 1905 1,420 11. 569600-0185 103 Logan Avenue S 4,363 SF home, built 1938 1,470 12. 569600-0180 XX Logan Avenue S 4,787 Vacant 13. 569600-0170 109 Logan Avenue S 5,000 SF home, built 1900 1,270 14. 569600-0169 XX Logan Avenue S 5,000 Vacant -- 15. 569600-0165 117 Logan Avenue S 5,000 SF home, 1900 980 16. 569600-0160 121 Logan Avenue S 5,000 SF Home, 1900 1,910 17. 569600-0155 127 Logan Avenue S 5,000 Duplex, 1907 2,370 18. 569600-0150 129 Logan Avenue S 5,000 SF home, 1901 1,760 19. 569600-0145 526 2nd Avenue S 5,000 Parking lot 20. 569600-0140 526 2nd Avenue S 5,000 El Kiosko, 1949 754 21. 000720-0167 54-56 Shattuck Avenue S 6,600 Duplex, Built 1948 1,630 22. 000720-0171 58-60 Shattuck Avenue S 6,534 Duplex, 1948 1,630 23. 000720-0034 300-302 S Tobin Street 6,969 Duplex, 1948 2,030 24. 000720-0035 312 S Tobin Street 8,701 SF Home, Built 1923 2,000 25. 000720-0033 314 S Tobin Street 8,889 SF Home, 1925 1,740 26. 000720-0036 316 S Tobin Street 10,197 SF Home, 1922 2,270 27. 000720-0037 402 S Tobin Street 17,859 SF Home, 1949 3,360 28. 000720-0179 406 S Tobin Street 12,750 SF Home, 1925 1,240 29. 000720-0038 408 S Tobin Street 5,250 SF Home, 1953 880 30. 000720-0060 409 S Tobin Street District Warehouse, 1964 Technical Information Report 3 New Renton High School Project No. 2230388.10 Parcel Property Address Lot size (SF) Current Use, Built Date Bldg. Size (SF) 31. 000720-0039 414 S Tobin Street 18,000 Parking Lot 32. 000720-0078 416 S Tobin Street 4,912 SF Home, 1997 1,080 33. 000720-0079 418 S Tobin Street 4,916 SF Home, 1997 1,080 34. 000720-0072 420 S Tobin Street 7,720 SF Home, 1902 2,080 35. 000720-0110 500 S Tobin Street 4,747 SF Home, 1902 1210 36. 000720-0108 502 S Tobin Street 5,335 SF Home, 2004 1,480 37. 000720-0114 504 S Tobin Street 6,881 SF Home, 1902 2,250 38. 000720-0040 508 S Tobin Street 16,965 SF Home, 2015 1,410 39. 000720-0127 509 S Tobin Street 7,840 SF Home, 1926 1,540 40. 000720-0128 513 S Tobin Street 5,500 Duplex, 1977 2,390 41. 000720-0041 518 S Tobin Street 11,291 SF Home, 1900 1,520 42. 000720-0214 311 S Tillicum Street 7,810 SF Home, 2007 2,550 43. 000720-0060 400 2nd Avenue S 1,011,898 Renton High School 264,797 The 2022 City of Renton Surface Water Design Manual (RSWDM) establishes the methodology and design criteria used for the project. 1.1 Project Phasing The New Renton High School project will be constructed in two phases. Phase 1 constructs parking and Phase 2 constructs the rest of the project. Phase 1 will include a new parking lot, drop-off lane, limited right-of-way improvements, and temporary construction staging areas, as well as associated utility and site improvements. The new parking lot will be located west of the 1930s wing of the existing building, and will include ADA stalls and landscape islands. The drop-off lane will be between S 2nd St and the 1930s and IPAC wings of the new building, and will include ADA stalls and landscape islands. Right-of-way improvements include new sidewalk and driveways on a portion of Lake Ave S and new driveways on S 2nd St. Temporary construction staging areas will be constructed at several areas on the site, and all will be removed in future construction phases. This phase will include a new storm detention system under the new parking lot, which will collect drainage from the new parking lot, as well as some of the existing building roof drains. It also includes some new treatment devices. The detention and treatment devices are designed to meet the needs of the entire development and not only Phase 1. Phase 1 construction will take place from July through November 2026. The first half of Phase 2 will include a new wing to the high school building, an access corridor, play fields, right-of-way improvements, as well as associated utility and site improvements. The new wing of the building will be located north and east of the existing IPAC. The access corridor will be constructed along the current location of S Tobin St, which will be removed. The playfields will be located north of the access corridor on land that the school district will purchase from private owners. This phase will construct right-of-way improvements on Airport Way, S Logan St, S Shattuck Ave, and S Tobin St. This phase will connect some of the roof drains to the detention system constructed in Phase 1 and will also provide additional stormwater treatment devices. This first half of Phase 2 work is expected to be constructed from September 2026 to September 2028. The second half of Phase 2 will include demolition of existing buildings, new parking areas, and limited right-of-way improvements. The 1960s wing of the existing building will be demolished, as well as some outbuildings. This second half of Phase 2 work is expected to be constructed from August 2028 to August 2029. Technical Information Report 4 New Renton High School Project No. 2230388.10 Phase 1 will include stormwater facilities for future phases to connect to. Each phase constructs the improvements required to mitigate itself, without depending on future improvements planned for later phases. Phase 1 and Phase 2 will each be their own plan set under two separate permits. This Stormwater Report is intended to address all phases of the project and describes the full completed project, unless noted. The stormwater facilities are not designed to mitigate the temporary construction staging areas because all will be removed in Phase 2 of construction. 2.0 Conditions and Requirements Summary The project triggers Full Drainage Review because it results in more than 7,000 square feet of land disturbing activity and over 2,000 square feet of new and/or replaced impervious surface. Below is a summary of how the proposed project will meet the Core Requirements (CR) and Special Requirements (SR). 2.1 CR 1 – Discharge at the Natural Location The site is located within the Lower Cedar River and the Black River Drainage Basins. The site is divided into three TDAs. Most of the site discharges to TDA 1 and TDA 2 to the Black River Wetlands, while a small portion discharges to TDA 3 to the Cedar River. The Black River Wetlands lead to the Duwamish River and to Puget Sound in the SoDo District in Seattle. The Cedar River leads to Lake Washington, which discharges through the Lake Washington Ship Canal to Puget Sound in the Ballard District of Seattle. 2.2 CR 2 – Offsite Analysis AHBL staff performed a Level One Downstream Analysis for the project on August 4, 2025. The analysis included: • Defining and mapping the study area. • Reviewing available information on the study area. • Field inspecting the study area. • Analyzing the existing drainage system, including its existing and predicted problems, if any. Please refer to Section 3.0 for the full offsite analysis. 2.3 CR 3 – Flow Control The Western Washington Hydrology Model (WWHM) was used to model the existing stormwater conditions and design a detention pipe system for the project. TDA 1 and TDA 2 discharge to the Black River, which requires flow control. Because the project areas have been urbanized with more than 40% impervious area since 1985, this TDA is subject to the Flow Control Duration Standard Match Existing Conditions requirement, in accordance with Section 1.2.3.1.B of the RSWDM. These TDAs are also subject to the wetland protection standard due to the wetland area around the Black River. TDA 3 discharges to the Cedar River. Per Section 1.2.3.1 of the RSWDM, Cedar River is one of the major receiving waters that qualifies for the direct discharge exemption. As a result, no flow control is required for TDA 3. Flow control will be provided through the use of buried detention pipes. WWHM is used to model the hydrologic conditions. Flow Control design is detailed in Section 4.4 of this report. Technical Information Report 5 New Renton High School Project No. 2230388.10 2.4 CR 4 – Conveyance System The project will collect drainage from parking lots, playfields, and roofs, and direct it through a series of underground pipes and catch basins to the public stormwater system. Drainage will be directed to detention or water quality facilities, where required. Conveyance calculations for Phase 1 are detailed in Section 5.0 of this report. Conveyance for Phase 2 will be provided in a future submittal. 2.5 CR 5 – Erosion and Sediment Control Onsite land disturbance will consist of clearing the work site, demolition, and regrading. Erosion and sediment control will be provided with the use of temporary and permanent seeding within the work limits, silt fence or wattles, inlet sediment protection, stabilized construction entrance, sedimentation ponds, and temporary stormwater tanks. A Temporary Erosion and Sedimentation Control Plan will be included in the permit plan set. Refer to Appendix F for the Stormwater Pollution Prevention and Spill (SWPPS) Plan. 2.6 CR 6 – Maintenance and Operations Maintenance and operations of all drainage facilities on the project site will be by the owner. Operations and Maintenance will be detailed in Section 10.0 of this report. 2.7 CR 7 – Financial Guarantees and Liability This project will provide financial guarantees and liability per City of Renton requirements. This is accomplished through the Bond Quantity Worksheet and Declaration of Covenants, and further detailed in Section 9.0 of this report. 2.8 CR 8 – Water Quality The new pollution generating impervious surfaces (PGIS) for the proposed site include the paved parking areas, maintenance, fire access loops, parking lot, vehicle access, and right-of-way improvements. Onsite flows will be treated to meet the performance standard of the Enhanced Basic Water Quality Menu by using BioPod structures manufactured by Oldcastle Precast and Filterra structures manufactured by Contech. The site is within Zones 1 and 2 of the Aquifer Protection Zone. Therefore, bioretention and stormwater wetlands are prohibited. Water quality is discussed in detail in Section 4.5 of this report. 2.9 CR 9 – Onsite BMPs This project is required to provide onsite BMPs to reduce the amount of runoff at the source. Site soils and the presence of the Aquifer Protection Zone limit the ability of this project to meet this standard. This is discussed in detail in Section 4.6 of this report. 2.10 SR 1 – Other Adopted Requirements The project is included in the Black River and Lower Cedar River Drainage Basins. There are no special requirements specific to these drainage basins. 2.11 SR 2 – Flood Hazard Delineation The proposed project is not in or adjacent to the 100-year floodplain. Refer to Appendix A-5 for the Floodplain Map. Technical Information Report 6 New Renton High School Project No. 2230388.10 2.12 SR 3 – Flood Protection Facilities This project does not rely on existing flood protection facilities, nor will it modify or construct new flood protection facilities. 2.13 SR 4 – Source Control The proposed project is an educational facility; it is classified as a commercial site for source control purposes. The dumpster area will have a roof and will drain to sanitary sewer to prevent stormwater from contamination. A proposed generator will have secondary containment to protect from fuel spills. 2.14 SR 5 – Oil Control The site does not meet high-use criteria and is not subject to oil control measures. 2.15 SR 6 – Aquifer Protection Area This project is located within Aquifer Protection Zones 1 and 2 per the City of Renton Sensitive Areas Aquifer Protection map. The east half of the site is in Zone 1 and the west half is in Zone 2. In Zone 1, stormwater facilities are not allowed to have direct contact with soil, while in Zone 2, such facilities are allowed with an impermeable liner. As a result, ponds, infiltration, and other facilities that require soil contact, are not permitted. Refer to Appendix A-6 for the Aquifer Protection map. 3.0 Offsite Analysis There are no upstream tributary areas contributing drainage to the basin area. 3.1 Task 1 – Study Area Definition and Maps The Renton School District (RSD) proposes to renovate and expand Renton High School at 400 South 2nd Street, Renton, Washington. AHBL staff visited the site on August 4, 2025. The project site lies within both the Black River and Lower Cedar River Drainage Basins, as delineated by the City of Renton COR Maps. The project site basin receives no upstream stormwater. The project discharges to three separate discharge locations that will be referred to as TDA 1, TDA 2, and TDA 3. Refer to Appendix A-7 for a map of the downstream system. TDA 1 Downstream Discharge 1 from TDA 1 is defined as the southernmost portion of the site. It has an area of 1.28 acres. The basin discharges west to the flow line in South 2nd Street and to the south to a storm line in Shattuck Avenue South. Technical Information Report 7 New Renton High School Project No. 2230388.10 Stormwater that flows south off the site is intercepted by one of five catch basins in the east flowline of South 2nd Street. All five of these catch basins are tightlined north to a 12- to 15-inch conveyance line running west on the north side of South 2nd Street that enters a Type II manhole at the intersection with Shattuck Avenue South. It is then directed south to a series of Type II manholes and an 18-inch stormwater main on the west side of Shattuck Avenue South. At the intersection with South 4th Place, the TDA is over the required one-quarter mile downstream of the project site. The discharge continues flowing south toward SW 7th Street for another quarter mile. At SW 7th Street, the discharge is rerouted west for about a mile. The stormwater then flows north on Naches Avenue South for about 650 feet, where the stormwater is discharged into the Black River. TDA 1 and TDA 2 converge at the 500 block of SW 7th Street. TDA 2 Downstream Discharge 2 from TDA 2 is defined as the west and center portions of the site. It has the largest area of all the basins, totaling 29.49 acres. TDA 2 stormwater discharges to the eastern flowline of Lake Avenue South, where it is intercepted by a series of Type I catch basins. Stormwater flows west 25 feet in an 8-inch pipe to a Type II catch basin at the north side of the intersection of South 2nd Street and Lake Avenue South. A 17-foot, 24-inch pipe conveys runoff across South 2nd Street to the south to another Type II catch basin, located in the adjacent sidewalk. A 30-inch pipe conveys stormwater south 77 feet to another Type II catch basin in the Safeway parking lot. The runoff travels through a 30-inch pipe, 373 feet southwest throughout a series of Type II manholes located within the Safeway parking lot. The runoff is then directed 315 feet west toward the neighboring property through a 36-inch pipe and Type II catch basins. The runoff then enters a 197-foot concrete pipe that travels below the intersection of SW Sunset Boulevard and Rainier Avenue South, connecting to a Type II catch basin located in the O’Reilly Auto Parts parking lot. The stormwater is then routed 364 feet through three Type II catch basins to a Type II catch basin located one-quarter mile from the project site. The stormwater is conveyed through a series of public and private stormwater mains and discharged into the Black River. TDA 1 and TDA 2 converge at the 500 block of SW 7th Street. TDA 3 Downstream TDA 3 stormwater discharges to the flowline of Logan Avenue South and drains east, where it is intercepted by a catch basin at the southwest corner of the intersection of Airport Way and Logan Avenue South. Stormwater will flow north in a 112-foot, 24-inch pipe to a Type II catch basin in the island in the middle of the intersection. A 24-inch pipe conveys water 119 feet north toward East Perimeter Drive to a Type II catch basin. A 24-inch concrete pipe conveys the water 74 feet north, discharging to the Cedar River. This discharge point is less than one-quarter mile from the project site. Technical Information Report 8 New Renton High School Project No. 2230388.10 Per the City of Renton COR Maps, the pipe outfall should be located 74 feet northwest of East Perimeter Road. AHBL could not locate the discharge point due to the discharge point being located on a steep ridge with heavy vegetation. 3.2 Task 2 – Resource Review The following resources were reviewed to discover any existing or potential problems in the study area: • Adopted Basin Plans: The project site lies within the Black River and Lower Cedar River Drainage Basins. Requirements for the Lower Cedar River Basin Plan will be followed where applicable. • Offsite Analysis Reports: AHBL staff has not located offsite analysis reports for projects near the Renton High School project site. • FEMA Map: FEMA Flood Insurance Rate Map 53033C0977G, dated August 19, 2020 (see Appendix A-5), indicates the project site lies within the 0.2% annual chance of flood hazard. • City of Renton Sensitive Areas Landslide Hazard Map (see Appendix A-8): The project site is not located within the sensitive areas Landslide Hazard Area. • City of Renton Aquifer Protection Zone Map (see Appendix A-6): The project site is within Aquifer Protection Zones 1 and 2. Requirements for Zones 1 and 2 of the Aquifer Protection Zone will be followed, where applicable. • City of Renton Coal Mine Hazard Map (see Appendix A-9): The project site is located outside the coal mine hazard area. • City of Renton Erosion Hazard Map (see Appendix A-10): The project site is not within an erosion hazard area. • City of Renton Steep Slopes Map (see Appendix A-11): The project site is not within the steep slope area. • Soils Information: Refer to Appendix B for the Geotechnical Report. 3.3 Task 3 – Field Inspection On August 4, 2025, AHBL staff performed a Downstream Analysis of the drainage system receiving stormwater runoff from the proposed Renton High School. 1. Investigate any problems reported or observed during the resource review: No problems were reported or observed during the resource review. 2. Locate all existing/potential constrictions or lack of capacity in the existing drainage system: No constrictions or lack of capacity in the existing drainage system was observed. 3. Identify all existing/potential downstream drainage problems as defined in Section 1.2.2.1: No existing/potential downstream drainage problems were observed. 4. Identify existing/potential overtopping, scouring, bank sloughing, or sedimentation: The vast majority of catch basins located within the roadways (South 2nd Street, Shattuck Avenue South, Tobin Avenue South, etc.) had roughly 2 to 3 inches of sediment. Technical Information Report 9 New Renton High School Project No. 2230388.10 5. Identify significant destruction of aquatic habitat or organisms (e.g., severe siltation, back erosion, or incision in a stream): No significant destruction of aquatic habitat or organisms was observed. 6. Collect qualitative data on features such as land use, impervious surfaces, topography, and soil types for the site: Land use on the project is a school site. Impervious surfaces include parking areas, buildings, and sidewalks. The topography is flat on the site, and the soil type is Ur, Urban Land. 7. Collect information on pipe sizes, channel characteristics, drainage structures, and relevant critical areas (e.g., wetlands, stream, and steep slopes): Pipe sizes were determined by using survey information and City of Renton COR Maps. 8. Verify tributary basins delineated in Task 1: Based on the topography onsite, the basin delineation based on the survey was confirmed. 9. Contact neighboring property owners or residents in the area about past or existing drainage problems and describe these in the report (optional): This requirement is not applicable for this project. Properties on the site basin are proposed for demolition. 10. Note the date and weather conditions at the time of the inspection: The site visit occurred on August 4, 2025. The weather was sunny and 73 degrees. 3.4 Task 4 – Drainage System Description and Problem Descriptions The site is located within the Lower Cedar River and Black River Drainage Basins. The site is divided into three TDAs: TDA 1 is located in the south portion of the site, TDA 2 is located in the central and western portion of the site, and TDA 3 is located in the northern and eastern portion of the site. The south basin (TDA 1) and central basin (TDA 2) drain to the public piped conveyance system that eventually discharges to the Black River. The east basin (TDA 3) drains to the public conveyance system, discharging to the Cedar River. No signs of flooding, overtopping, or erosion were evident at the time of the inspection. 4.0 Flow Control, Low Impact Development (LID), and Water Quality Facility Analysis and Design 4.1 Existing Site Hydrology The site is located in three TDAs, which are described above in Section 3.4. Refer to Figure A-3, Existing Basins Map, for delineation of the existing drainage areas. 4.1.1 TDA 1 (Black River) Area (Acre) Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year 0.31 1.06 1.37 0.42 0.62 0.90 Technical Information Report 10 New Renton High School Project No. 2230388.10 4.1.2 TDA 2 (Black River) Area (Acre) Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year 10.57 17.88 28.45 7.50 11.33 16.68 4.1.3 TDA 3 (Cedar River) Area (Acre) Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year 2.08 4.89 6.97 2.00 2.97 4.32 4.2 Developed Site Hydrology The developed site will maintain the same three TDAs as the existing site. Refer to Figure A-12, Proposed Basin Map, for delineation of the developed drainage areas and flow routes. 4.2.1 TDA 1 (Black River) Area (Acre) Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year Basin 1 0.49 0.68 1.17 0.23 0.38 0.59 The flows for this TDA are reduced compared to existing conditions because the total area of this basin will be reduced by the proposed development. 4.2.2 TDA 2 (Black River) Area (Acre) Detained Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year Basin 2A 8.17 13.95 22.12 Basin 2B 1.06 5.61 6.67 Total 9.23 19.56 28.79 6.75 10.05 14.78 The flows for this TDA are reduced compared to existing conditions due to a detention system in the southwest portion of the site. 4.2.3 TDA 3 (Cedar River) Area (Acre) Peak Flow (cfs) Till Grass Impervious Total 2-Year 10-Year 100-Year Basin 3 1.15 5.69 6.84 2.24 3.28 4.69 Flows for this basin are slightly increased. However, TDA 3 is flow-control exempt and matching flows is not required. Technical Information Report 11 New Renton High School Project No. 2230388.10 4.3 Performance Standards TDA 1 and TDA 2 are subject to the Flow Control Duration Standard – Match Existing Site Conditions. This flow control duration standard requires runoff from urban developments to be detained and released at a rate that matches the flow duration of the existing condition rates from the 2-, 10-, and 100-year peak flow. The proposed detention pipes will detain and release water at controlled rates, meeting the Flow Control standards. In TDA 3, flow control is not required due to the direct discharge exemption noted is Section 1.2.3.1 of the RSWDM. In accordance with the RSWDM, onsite flows from the PGIS will be treated to meet the performance standards for the Enhanced Basic Water Quality Menu. The proposed BioPod and Filterra structures will exceed the performance standards of the Enhanced Basic Water Quality Menu. 4.4 Flow Control System The proposed stormwater flow control system is designed to meet the requirements of the RSWDM. Flow control will be provided through the use detention within buried detention pipe. WWHM was used to size the detention tank and outlet structures. RSWDM Section 1.2.3.3 states “all proposed projects, including redevelopment projects, must provide onsite flow control facilities to mitigate the impacts of increased storm and surface water runoff generated by the addition of new impervious surface and any related land conversion.” Based on the site being in Aquifer Protection Zones 1 and 2, infiltration is not allowed onsite. In addition, the geotechnical report indicates the site soils are not conducive for infiltration. Therefore, a detention system is proposed for the project area. The proposed project includes four playfields. Three of these playfields will be artificial turf fields with underdrains, while the fourth will use natural turf without underdrains. Per City of Renton standards, fields with underdrains must be modeled as 100% pollutant-generating impervious area. The field without underdrains will be modeled as lawn. The natural turf play field will be located at the west end of the site in Aquifer Protection Zone 2. Section 6.2.4 of the RSWDM requires such facilities to have a liner, unless infiltration rates are less than 2.4 inches per hour and the soil meets cation exchange and organics requirements. Testing from the geotechnical engineer shows that the soils meet these requirements and, as a result, this field does not require an underdrain and can be modeled as lawn. Flow control calculations were performed using WWHM. Calculations are provided as Appendix C. 4.5 Water Quality System The new PGIS for the proposed site includes all paved parking and maintenance access areas, as well as the artificial turf fields. As mentioned above, onsite flows will be treated to specifications provided by the Enhanced Basic Water Quality standards of the City’s drainage code, using Oldcastle BioPod or Contech Filterra structures. City of Renton requires artificial turf and rubberized track to be treated as pollutant generating surfaces. Because of the layout of the surrounding public streets, and area exchange is required to meet the water quality standard. Appendix A-13 shows the areas that require treatment, as well as showing how the area exchange proposed meets the stormwater requirements. Technical Information Report 12 New Renton High School Project No. 2230388.10 BioPods 1, 6, and 10 will be located upstream of the proposed detention system. In our discussions with Oldcastle, they informed us that in order for the BioPod units to work properly, the bottom of the treatment media needs to be at or above the 2-year level of the detention system. Our calculations in WWHM show the 2-year level to be 2.92 feet above the bottom of the pipe, at 25.50, giving a 2-year elevation of 28.42. As a result, we set the bottom of the treatment media at 28.42, resulting in an outlet pipe 6 inches lower at 27.92. Water quality basins are mapped in Appendix A-14. Per RSWDM Section 3.2, WWHM was used to size the BioPod and Filterra structures (see Appendix D, Water Quality Calculations). 4.6 Onsite BMPs RSWDM Core Requirement 9 states that projects must apply onsite BMPs to either supplement the flow mitigation provided by required flow control facilities or provide flow mitigation where flow control facilities are not required. Such requirements are subject to infeasibility criteria described in the RSWDM. The project falls under the Large Lot High Impervious BMP Requirements, which are listed in Section 1.2.9.2.2. The Geotechnical Report dated September 3, 2025, states that small-scale infiltration facilities may be feasible for this project in Aquifer Protection Zone 2 in the west half of the project. The geotechnical engineer provided a clarification letter dated January 9, 2026, stating that only shallow, low-capacity, infiltration BMPs will be feasible for this project, but infiltration facilities for large structures are not feasible. Large structures where such BMPs are infeasible include the proposed building, athletic fields, and the proposed parking areas. Infiltration BMPs could potentially be used for small buildings or storage sheds. At the time of this report, only Phase 1 has been designed in enough detail to analyze compliance with Core Requirement 9. Phase 2 will be reviewed in detail in a future submittal. This requirement requires us to address the following items in the order listed: 1. Full Dispersion • This measure is not feasible because there are no native vegetated surfaces on or near the project site. 2. Full Infiltration of Roof Runoff • No new roof areas are required for Phase 1 of the project, so this requirement does not apply to Phase 1. This measure may be feasible for the portions of Phase 2 that are located in Aquifer Protection Zone 2, which will be reviewed in a future submittal. 3. The following measures must be reviewed: Full Infiltration • Per Section C.2.2.2 of the RSWDM, Full Infiltration is not permitted in areas of fill soils. The geotechnical letter dated January 9, 2026, notes that most of the project area is underlaid with uncontrolled fills, which makes Full Infiltration infeasible for this project. Technical Information Report 13 New Renton High School Project No. 2230388.10 Limited Infiltration • Section C.2.3.2 of the RSWDM states that Limited Infiltration is subject to the same limitation, except that it allows for more native soil types. However, this section does not list uncontrolled fills as a permitted soil type for this BMP. As a result, Limited Infiltration is infeasible for this project. Bioretention • Section C.2.6 of the RSWDM includes a list of infeasibility criteria where bioretention is not required. Infeasibility Criteria 1 states that Bioretention is not feasible when the geotechnical engineer recommends that infiltration not be used. Because the geotechnical engineer recommends against using this measure for large-scale facilities, Bioretention is infeasible for this project. Permeable Pavement • Section C.2.7 of the RSWDM includes a list of infeasibility criteria where permeable pavement is not required. Infeasibility Criteria 1 states that Permeable Pavement is not feasible when the geotechnical engineer recommends that infiltration not be used. Because the geotechnical engineer recommends against using this measure for large- scale facilities, Permeable Pavement is infeasible for this project. 4. Basic Dispersion • Basic Dispersion is not feasible for Phase 1 of the project because all possible dispersion locations are either on property not owned by the school district or in areas that are slated for future development in Phase 2. Basin Dispersion for Phase 2 will be analyzed in a future submittal. 5. BMPs must be implemented for impervious areas, as noted: • This project will have impervious coverage of more than 65%. As a result, onsite BMPs must be applied to 20% of the impervious areas or 10% of the site, whichever is less. The total impervious area is 28.03 acres, which would require 5.6 acres to be mitigated. The entire site area is 36.50 acres, which would require 3.6 acres to be mitigated. The lower number of 3.6 acres is the requirement for this site. Because of the soil conditions on the site and the presence of Aquifer Protection Zone 1 on half the site, it will not be possible for the project to meet this requirement. As a result, we must review the following BMPs: Reduced Impervious Surface Credit • The Reduced Impervious Surface Credit lists four measures to consider, as described in Section C.2.9 of the RSWDM. The project exceeds the maximum area allowed for the Restricted Footprint noted in C.2.9.2. Wheel strip driveways per Section C.2.9.2 are not feasible because they do not meet the requirements for fire access. Neither Minimum Disturbance Foundation (C.2.9.4) nor Open Grid Decking (C.2.9.5) are feasible for the proposed buildings for this project. As a result, the Reduced Impervious Surface Credit is not feasible for this project. Technical Information Report 14 New Renton High School Project No. 2230388.10 Native Growth Retention Credit • The Native Growth Retention Credit described in Section C.2.10 is not feasible for this project because there are no native growth areas on the site. The creation of new such areas would be infeasible for school operations. Tree Retention Credit • This project will preserve several existing trees on the property. All such trees will be protected with construction fencing and by not grading in the area around the tree. 6. Protect the soil moisture holding capacity of new pervious surfaces. • Soils will be prepared in accordance with the Soil Amendment requirements described in Section C.2.13 of the RSWDM. Details will be shown on the landscape plans. 7. Perforated Pipe Connection • No new roof areas are required for Phase 1 of the project, so this requirement does not apply to Phase 1. This measure may be feasible for the portions of Phase 2 that are located in Aquifer Protection Zone 2, which will be reviewed in a future submittal. 5.0 Conveyance System Analysis and Design Based on RSWDM Section 1.2.4.1, new pipe systems shall be designed with sufficient capacity to convey and contain the 25-year peak flow, with a minimum of 6 inches of freeboard between the design water surface and structure grate. In addition, runoff from the 100-year peak storm event shall not create or aggravate a severe flooding problem or severe erosion problem. The new pipe system has sufficient capacity for a 25-year peak flow, and the system has been designed to provide more than 6 inches of freeboard between the design water surface and structure grate during the 25-year peak storm event. No severe flooding problems or severe erosion problems will be created or aggravated in the 100-year storm event. Parking lot drainage will be collected in catch basins and directed through a series of underground pipes to BioPod water quality systems. Roof drainage will be collected in a series of 6-inch pipes before being directed to existing storm drainage systems, both onsite and in the right-of-way. Drainage for play fields will be collected through an underdrain system to BioPod devices. The southwest portion of the site will be directed to a detention tank system, with the remainder going directly to the public drainage system without detention. The conveyance models assume that the water level in the detention system will be at the riser overflow elevation of 30.0, a conservative assumption that will rarely be the case. Conveyance calculations for Phase 1 improvements are included in Appendix E. These calculations include areas for future roof drains and athletic fields that will be constructed in Phase 2. Full conveyance calculations for Phase 2 will be provided in a future submittal. 6.0 Special Reports and Studies A Geotechnical Report dated September 3, 2025, prepared by Associated Earth Sciences, Inc., can be found in Appendix B. Technical Information Report 15 New Renton High School Project No. 2230388.10 7.0 Other Permits This project will be constructed in phases. The phasing plan is described in Section 1.1, above. In addition, a National Pollutant Discharge Elimination System (NPDES) General Permit will be required for this project. This project will also need permits from the Federal Aviation Administration (FAA) due to its proximity to Renton Airport. 8.0 Stormwater Pollution Prevention and Spill Plan (SWPPS) Analysis and Design The proposed development shall comply with guidelines set forth in City of Renton drainage requirements. The plan will include erosion/sedimentation control features designed to prevent sediment-laden runoff from leaving the site or adversely affecting critical water resources during construction. The following measures will be shown on the ESC plans and will be used to control sedimentation/ erosion processes: • Clearing Limits – All areas to remain undisturbed during the construction of the project will be delineated prior to any site clearing or grading. • Cover Measures – Cover measures will be implemented for the disturbed areas. • Perimeter Protection – Filter fabric fences for site runoff protection will be provided at the downstream site perimeter. • Traffic Area Stabilization – Traffic area stabilization is not applicable for this project. • Sediment Retention – Inlet sediment protection will be utilized as part of this project. • Storm Drain Inlet Protection – Inlet sediment protection will be provided on all new and existing catch basins downstream of construction activities. • Surface Water Collection – Catch basins and conveyance pipes will provide surface water collection. • Dewatering Control – Dewatering Control is not applicable for this project. • Dust Control – Dust control measures, including sweeping and water truck, will be implemented when exposed soils are dry to the point that wind transport is possible; and roadways, drainage ways, or surface waters are likely to be impacted. • Flow Control – Flow control is provided with sediment ponds and temporary stormwater tanks. These measures are discussed in detail in the Stormwater Pollution Prevention and Spill (SWPPS) Plan included in Appendix F. 9.0 Bond Quantities, Facility Summaries, and Declaration of Covenant Bond Quantities and a Declaration of Covenant for Phase 1 are included in Appendix G. Phase 2 will be provided in a future submittal. Technical Information Report 16 New Renton High School Project No. 2230388.10 10.0 Operations and Maintenance Manual Maintenance and operations of all onsite drainage facilities will be maintained by the Renton School District. The Operations and Maintenance Manual is included in Appendix H. 11.0 Conclusion This site has been designed to meet or exceed the requirements of the 2022 City of Renton Surface Water Design Manual. Flow calculations and modeling use City of Renton standards for sizing stormwater conveyance. This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. AHBL, Inc. Brian Schend, PE Senior Engineer BJS/lsk September 2025 Revised January 2026 Revised April 2026 Revised June 2026 Q:\2023\2230388\WORDPROC\Reports\20260610 Rpt (TIR) 2230388.10.docx Technical Information Report New Renton High School Project No. 2230388.10 Appendix A Exhibits A-1 .................... Technical Information Report Worksheet A-2 .................... Vicinity Map A-3 .................... Existing Basins Map A-4 .................... NRCS Soils Map A-5 .................... Floodplain Map A-6 .................... Aquifer Protection Map A-7 .................... Downstream Drainage Map A-8 .................... Landslide Hazard Map A-9 .................... Coal Mine Hazard Map A-10 .................. Erosion Hazard Map A-11 .................. Steep Slopes Map A-12 .................. Proposed Basin Map A-13 .................. Water Quality Areas A-14 .................. Water Quality Basins 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 __________________ __________________ __________________ Renton School District Renton School District 7812 S 124th St Seattle, WA 98173 William Fierst, PE AHBL 253-383-2422 Renton High School 23 N 5 E 18 400 S 2nd St, Renton, WA FAA Airport January 2026 January 2026 Appendix A-1 April 2026 April 2026 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 ______________________ _____________________________________ Not applicable TDA 1 and TDA 2: Black River. TDA 3: Cedar River City Center Urban Design District A & D, FAR Part 77 Airport restrictions Subject to Aquifer Protection Zone 1 and 2 Appendix A-1 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 UR-Urban Land Less than 5%Minimal Aquifer Protection Zone Appendix A-1 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 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 TDA 1 - Black River 1 August 2025 None required NA To be determined Appendix A-1 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: Not applicable School Trash collection and cleanup Appendix A-1 Biopod & Filterra 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 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 TDA 2 - Black River 1 August 2025 Detention Tank NA To be determined Appendix A-1 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: Not applicable School Trash collection and cleanup Appendix A-1 Biopod & Filterra 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 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 TDA 3 - Cedar River 1 August 2025 None NA To be determined Basin is flow-control exempt Appendix A-1 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: Not applicable School Trash collection and cleanup Appendix A-1 Biopod & Filterra 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 _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ Detention tank Biopod Appendix A-1 Filterra 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 Appendix A-1 03/27/2026 VICINITY MAP I405 AIRPORT WAY S TOBIN ST S 2ND ST R A I N I E R A V E A-2 Vicinity Map T T T T T TTT T TDA 3 PERVIOUS 2.08 AC IMPERVIOUS 4.89 AC TOTAL AREA 6.97 AC TDA 2 PERVIOUS 10.57 AC IMPERVIOUS 17.88 AC TOTAL AREA 28.45 AC TDA 1 PERVIOUS 0.31 AC IMPERVIOUS 1.06 AC TOTAL AREA 1.37 AC S TOBIN ST S TOBIN ST SH A T T U C K A V E S AIRPORT WAY LO G A N A V E S LO G A N A V E S LA K E A V E S S 2nd ST S TILLICUM ST 1930s BUILDING 1990s BUILDING (IPAC) 1960s BUILDING 1960s BUILDING 1960s BUILDING 1960s BUILDING 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL EXISTING BASINS MAP A-3 2230388.10 3/31/2026 LEGEND TDA 1 - BLACK RIVER TDA 2 - BLACK RIVER TDA 3 - CEDAR RIVER N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 United States Department of Agriculture A product of the National Cooperative Soil Survey, a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local participants Custom Soil Resource Report for King County Area, Washington Soil Map - Renton High School Natural Resources Conservation Service September 9, 2025 Appendix A-4 Preface Soil surveys contain information that affects land use planning in survey areas. They highlight soil limitations that affect various land uses and provide information about the properties of the soils in the survey areas. Soil surveys are designed for many different users, including farmers, ranchers, foresters, agronomists, urban planners, community officials, engineers, developers, builders, and home buyers. Also, conservationists, teachers, students, and specialists in recreation, waste disposal, and pollution control can use the surveys to help them understand, protect, or enhance the environment. Various land use regulations of Federal, State, and local governments may impose special restrictions on land use or land treatment. Soil surveys identify soil properties that are used in making various land use or land treatment decisions. The information is intended to help the land users identify and reduce the effects of soil limitations on various land uses. The landowner or user is responsible for identifying and complying with existing laws and regulations. Although soil survey information can be used for general farm, local, and wider area planning, onsite investigation is needed to supplement this information in some cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/ portal/nrcs/main/soils/health/) and certain conservation and engineering applications. For more detailed information, contact your local USDA Service Center (https://offices.sc.egov.usda.gov/locator/app?agency=nrcs) or your NRCS State Soil Scientist (http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/contactus/? cid=nrcs142p2_053951). Great differences in soil properties can occur within short distances. Some soils are seasonally wet or subject to flooding. Some are too unstable to be used as a foundation for buildings or roads. Clayey or wet soils are poorly suited to use as septic tank absorption fields. A high water table makes a soil poorly suited to basements or underground installations. The National Cooperative Soil Survey is a joint effort of the United States Department of Agriculture and other Federal agencies, State agencies including the Agricultural Experiment Stations, and local agencies. The Natural Resources Conservation Service (NRCS) has leadership for the Federal part of the National Cooperative Soil Survey. Information about soils is updated periodically. Updated information is available through the NRCS Web Soil Survey, the site for official soil survey information. The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require 2 Appendix A-4 alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination, write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer. 3 Appendix A-4 Contents Preface....................................................................................................................2 How Soil Surveys Are Made..................................................................................5 Soil Map..................................................................................................................8 Soil Map................................................................................................................9 Legend................................................................................................................10 Map Unit Legend................................................................................................11 Map Unit Descriptions.........................................................................................11 King County Area, Washington.......................................................................13 Ur—Urban land...........................................................................................13 References............................................................................................................14 4 Appendix A-4 How Soil Surveys Are Made Soil surveys are made to provide information about the soils and miscellaneous areas in a specific area. They include a description of the soils and miscellaneous areas and their location on the landscape and tables that show soil properties and limitations affecting various uses. Soil scientists observed the steepness, length, and shape of the slopes; the general pattern of drainage; the kinds of crops and native plants; and the kinds of bedrock. They observed and described many soil profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The profile extends from the surface down into the unconsolidated material in which the soil formed or from the surface down to bedrock. The unconsolidated material is devoid of roots and other living organisms and has not been changed by other biological activity. Currently, soils are mapped according to the boundaries of major land resource areas (MLRAs). MLRAs are geographically associated land resource units that share common characteristics related to physiography, geology, climate, water resources, soils, biological resources, and land uses (USDA, 2006). Soil survey areas typically consist of parts of one or more MLRA. The soils and miscellaneous areas in a survey area occur in an orderly pattern that is related to the geology, landforms, relief, climate, and natural vegetation of the area. Each kind of soil and miscellaneous area is associated with a particular kind of landform or with a segment of the landform. By observing the soils and miscellaneous areas in the survey area and relating their position to specific segments of the landform, a soil scientist develops a concept, or model, of how they were formed. Thus, during mapping, this model enables the soil scientist to predict with a considerable degree of accuracy the kind of soil or miscellaneous area at a specific location on the landscape. Commonly, individual soils on the landscape merge into one another as their characteristics gradually change. To construct an accurate soil map, however, soil scientists must determine the boundaries between the soils. They can observe only a limited number of soil profiles. Nevertheless, these observations, supplemented by an understanding of the soil-vegetation-landscape relationship, are sufficient to verify predictions of the kinds of soil in an area and to determine the boundaries. Soil scientists recorded the characteristics of the soil profiles that they studied. They noted soil color, texture, size and shape of soil aggregates, kind and amount of rock fragments, distribution of plant roots, reaction, and other features that enable them to identify soils. After describing the soils in the survey area and determining their properties, the soil scientists assigned the soils to taxonomic classes (units). Taxonomic classes are concepts. Each taxonomic class has a set of soil characteristics with precisely defined limits. The classes are used as a basis for comparison to classify soils systematically. Soil taxonomy, the system of taxonomic classification used in the United States, is based mainly on the kind and character of soil properties and the arrangement of horizons within the profile. After the soil 5 Appendix A-4 scientists classified and named the soils in the survey area, they compared the individual soils with similar soils in the same taxonomic class in other areas so that they could confirm data and assemble additional data based on experience and research. The objective of soil mapping is not to delineate pure map unit components; the objective is to separate the landscape into landforms or landform segments that have similar use and management requirements. Each map unit is defined by a unique combination of soil components and/or miscellaneous areas in predictable proportions. Some components may be highly contrasting to the other components of the map unit. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The delineation of such landforms and landform segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, onsite investigation is needed to define and locate the soils and miscellaneous areas. Soil scientists make many field observations in the process of producing a soil map. The frequency of observation is dependent upon several factors, including scale of mapping, intensity of mapping, design of map units, complexity of the landscape, and experience of the soil scientist. Observations are made to test and refine the soil-landscape model and predictions and to verify the classification of the soils at specific locations. Once the soil-landscape model is refined, a significantly smaller number of measurements of individual soil properties are made and recorded. These measurements may include field measurements, such as those for color, depth to bedrock, and texture, and laboratory measurements, such as those for content of sand, silt, clay, salt, and other components. Properties of each soil typically vary from one point to another across the landscape. Observations for map unit components are aggregated to develop ranges of characteristics for the components. The aggregated values are presented. Direct measurements do not exist for every property presented for every map unit component. Values for some properties are estimated from combinations of other properties. While a soil survey is in progress, samples of some of the soils in the area generally are collected for laboratory analyses and for engineering tests. Soil scientists interpret the data from these analyses and tests as well as the field-observed characteristics and the soil properties to determine the expected behavior of the soils under different uses. Interpretations for all of the soils are field tested through observation of the soils in different uses and under different levels of management. Some interpretations are modified to fit local conditions, and some new interpretations are developed to meet local needs. Data are assembled from other sources, such as research information, production records, and field experience of specialists. For example, data on crop yields under defined levels of management are assembled from farm records and from field or plot experiments on the same kinds of soil. Predictions about soil behavior are based not only on soil properties but also on such variables as climate and biological activity. Soil conditions are predictable over long periods of time, but they are not predictable from year to year. For example, soil scientists can predict with a fairly high degree of accuracy that a given soil will have a high water table within certain depths in most years, but they cannot predict that a high water table will always be at a specific level in the soil on a specific date. After soil scientists located and identified the significant natural bodies of soil in the survey area, they drew the boundaries of these bodies on aerial photographs and Custom Soil Resource Report 6 Appendix A-4 identified each as a specific map unit. Aerial photographs show trees, buildings, fields, roads, and rivers, all of which help in locating boundaries accurately. Custom Soil Resource Report 7 Appendix A-4 Soil Map The soil map section includes the soil map for the defined area of interest, a list of soil map units on the map and extent of each map unit, and cartographic symbols displayed on the map. Also presented are various metadata about data used to produce the map, and a description of each soil map unit. 8 Appendix A-4 9 Custom Soil Resource Report Soil Map 52 5 8 9 1 0 52 5 8 9 9 0 52 5 9 0 7 0 52 5 9 1 5 0 52 5 9 2 3 0 52 5 9 3 1 0 52 5 9 3 9 0 52 5 8 9 1 0 52 5 8 9 9 0 52 5 9 0 7 0 52 5 9 1 5 0 52 5 9 2 3 0 52 5 9 3 1 0 52 5 9 3 9 0 558890 558970 559050 559130 559210 559290 559370 559450 559530 559610 559690 559770 558890 558970 559050 559130 559210 559290 559370 559450 559530 559610 559690 559770 47° 29' 7'' N 12 2 ° 1 3 ' 6 ' ' W 47° 29' 7'' N 12 2 ° 1 2 ' 2 2 ' ' W 47° 28' 50'' N 12 2 ° 1 3 ' 6 ' ' W 47° 28' 50'' N 12 2 ° 1 2 ' 2 2 ' ' W N Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 100 200 400 600 Feet 0 35 70 140 210 Meters Map Scale: 1:2,470 if printed on B landscape (17" x 11") sheet. Soil Map may not be valid at this scale. Appendix A-4 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. Custom Soil Resource Report 10 Appendix A-4 Map Unit Legend Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI Ur Urban land 41.5 100.0% Totals for Area of Interest 41.5 100.0% Map Unit Descriptions The map units delineated on the detailed soil maps in a soil survey represent the soils or miscellaneous areas in the survey area. The map unit descriptions, along with the maps, can be used to determine the composition and properties of a unit. A map unit delineation on a soil map represents an area dominated by one or more major kinds of soil or miscellaneous areas. A map unit is identified and named according to the taxonomic classification of the dominant soils. Within a taxonomic class there are precisely defined limits for the properties of the soils. On the landscape, however, the soils are natural phenomena, and they have the characteristic variability of all natural phenomena. Thus, the range of some observed properties may extend beyond the limits defined for a taxonomic class. Areas of soils of a single taxonomic class rarely, if ever, can be mapped without including areas of other taxonomic classes. Consequently, every map unit is made up of the soils or miscellaneous areas for which it is named and some minor components that belong to taxonomic classes other than those of the major soils. Most minor soils have properties similar to those of the dominant soil or soils in the map unit, and thus they do not affect use and management. These are called noncontrasting, or similar, components. They may or may not be mentioned in a particular map unit description. Other minor components, however, have properties and behavioral characteristics divergent enough to affect use or to require different management. These are called contrasting, or dissimilar, components. They generally are in small areas and could not be mapped separately because of the scale used. Some small areas of strongly contrasting soils or miscellaneous areas are identified by a special symbol on the maps. If included in the database for a given area, the contrasting minor components are identified in the map unit descriptions along with some characteristics of each. A few areas of minor components may not have been observed, and consequently they are not mentioned in the descriptions, especially where the pattern was so complex that it was impractical to make enough observations to identify all the soils and miscellaneous areas on the landscape. The presence of minor components in a map unit in no way diminishes the usefulness or accuracy of the data. The objective of mapping is not to delineate pure taxonomic classes but rather to separate the landscape into landforms or landform segments that have similar use and management requirements. The delineation of such segments on the map provides sufficient information for the development of resource plans. If intensive use of small areas is planned, however, onsite investigation is needed to define and locate the soils and miscellaneous areas. Custom Soil Resource Report 11 Appendix A-4 An identifying symbol precedes the map unit name in the map unit descriptions. Each description includes general facts about the unit and gives important soil properties and qualities. Soils that have profiles that are almost alike make up a soil series. Except for differences in texture of the surface layer, all the soils of a series have major horizons that are similar in composition, thickness, and arrangement. Soils of one series can differ in texture of the surface layer, slope, stoniness, salinity, degree of erosion, and other characteristics that affect their use. On the basis of such differences, a soil series is divided into soil phases. Most of the areas shown on the detailed soil maps are phases of soil series. The name of a soil phase commonly indicates a feature that affects use or management. For example, Alpha silt loam, 0 to 2 percent slopes, is a phase of the Alpha series. Some map units are made up of two or more major soils or miscellaneous areas. These map units are complexes, associations, or undifferentiated groups. A complex consists of two or more soils or miscellaneous areas in such an intricate pattern or in such small areas that they cannot be shown separately on the maps. The pattern and proportion of the soils or miscellaneous areas are somewhat similar in all areas. Alpha-Beta complex, 0 to 6 percent slopes, is an example. An association is made up of two or more geographically associated soils or miscellaneous areas that are shown as one unit on the maps. Because of present or anticipated uses of the map units in the survey area, it was not considered practical or necessary to map the soils or miscellaneous areas separately. The pattern and relative proportion of the soils or miscellaneous areas are somewhat similar. Alpha-Beta association, 0 to 2 percent slopes, is an example. An undifferentiated group is made up of two or more soils or miscellaneous areas that could be mapped individually but are mapped as one unit because similar interpretations can be made for use and management. The pattern and proportion of the soils or miscellaneous areas in a mapped area are not uniform. An area can be made up of only one of the major soils or miscellaneous areas, or it can be made up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example. Some surveys include miscellaneous areas. Such areas have little or no soil material and support little or no vegetation. Rock outcrop is an example. Custom Soil Resource Report 12 Appendix A-4 King County Area, Washington Ur—Urban land Map Unit Composition Urban land:100 percent Estimates are based on observations, descriptions, and transects of the mapunit. Description of Urban Land Interpretive groups Land capability classification (irrigated): None specified Land capability classification (nonirrigated): 8 Hydric soil rating: No Custom Soil Resource Report 13 Appendix A-4 References American Association of State Highway and Transportation Officials (AASHTO). 2004. Standard specifications for transportation materials and methods of sampling and testing. 24th edition. American Society for Testing and Materials (ASTM). 2005. Standard classification of soils for engineering purposes. ASTM Standard D2487-00. Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe. 1979. Classification of wetlands and deep-water habitats of the United States. U.S. Fish and Wildlife Service FWS/OBS-79/31. Federal Register. July 13, 1994. Changes in hydric soils of the United States. Federal Register. September 18, 2002. Hydric soils of the United States. Hurt, G.W., and L.M. Vasilas, editors. Version 6.0, 2006. Field indicators of hydric soils in the United States. National Research Council. 1995. Wetlands: Characteristics and boundaries. Soil Survey Division Staff. 1993. Soil survey manual. Soil Conservation Service. U.S. Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/national/soils/?cid=nrcs142p2_054262 Soil Survey Staff. 1999. Soil taxonomy: A basic system of soil classification for making and interpreting soil surveys. 2nd edition. Natural Resources Conservation Service, U.S. Department of Agriculture Handbook 436. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053577 Soil Survey Staff. 2010. Keys to soil taxonomy. 11th edition. U.S. Department of Agriculture, Natural Resources Conservation Service. http:// www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/?cid=nrcs142p2_053580 Tiner, R.W., Jr. 1985. Wetlands of Delaware. U.S. Fish and Wildlife Service and Delaware Department of Natural Resources and Environmental Control, Wetlands Section. United States Army Corps of Engineers, Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual. Waterways Experiment Station Technical Report Y-87-1. United States Department of Agriculture, Natural Resources Conservation Service. National forestry manual. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/ home/?cid=nrcs142p2_053374 United States Department of Agriculture, Natural Resources Conservation Service. National range and pasture handbook. http://www.nrcs.usda.gov/wps/portal/nrcs/ detail/national/landuse/rangepasture/?cid=stelprdb1043084 14 Appendix A-4 United States Department of Agriculture, Natural Resources Conservation Service. National soil survey handbook, title 430-VI. http://www.nrcs.usda.gov/wps/portal/ nrcs/detail/soils/scientists/?cid=nrcs142p2_054242 United States Department of Agriculture, Natural Resources Conservation Service. 2006. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture Handbook 296. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/national/soils/? cid=nrcs142p2_053624 United States Department of Agriculture, Soil Conservation Service. 1961. Land capability classification. U.S. Department of Agriculture Handbook 210. http:// www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_052290.pdf Custom Soil Resource Report 15 Appendix A-4 1DWLRQDO)ORRG+D]DUG/D\HU),50HWWH ˘˘˘ )HHW ı 6((),65(3257)25'(7$,/('/(*(1'$1',1'(;0$3)25),503$1(//$<287 63(&,$/)/22' +$=$5'$5($6 :LWKRXW%DVH)ORRG(OHYDWLRQ%)( =RQH$9$˝˝ :LWK%)(RU'HSWK =RQH$($2$+9($5 5HJXODWRU\)ORRGZD\ $QQXDO&KDQFH)ORRG+D]DUG$UHDV RIDQQXDOFKDQFHIORRGZLWKDYHUDJH GHSWKOHVVWKDQRQHIRRWRUZLWKGUDLQDJH DUHDVRIOHVVWKDQRQHVTXDUHPLOH =RQH; )XWXUH&RQGLWLRQV$QQXDO &KDQFH)ORRG+D]DUG =RQH; $UHDZLWK5HGXFHG)ORRG5LVNGXHWR /HYHH6HH1RWHV =RQH; $UHDZLWK)ORRG5LVNGXHWR/HYHH =RQH' 126&5((1 $UHDRI0LQLPDO)ORRG+D]DUG =RQH; $UHDRI8QGHWHUPLQHG)ORRG+D]DUG =RQH' &KDQQHO&XOYHUWRU6WRUP6HZHU /HYHH'LNHRU)ORRGZDOO &URVV6HFWLRQVZLWK$QQXDO&KDQFH ˆ˘:DWHU6XUIDFH(OHYDWLRQ &RDVWDO7UDQVHFW &RDVWDO7UDQVHFW%DVHOLQH 3URILOH%DVHOLQH +\GURJUDSKLF)HDWXUH %DVH)ORRG(OHYDWLRQ/LQH%)( (IIHFWLYH/205V /LPLWRI6WXG\ -XULVGLFWLRQ%RXQGDU\ 'LJLWDO'DWD$YDLODEOH 1R'LJLWDO'DWD$YDLODEOH 8QPDSSHG 7KLVPDSFRPSOLHVZLWK)(0$VVWDQGDUGVIRUWKHXVHRI GLJLWDOIORRGPDSVLILWLVQRWYRLGDVGHVFULEHGEHORZ 7KHEDVHPDSVKRZQFRPSOLHVZLWK)(0$VEDVHPDS DFFXUDF\VWDQGDUGV 7KHIORRGKD]DUGLQIRUPDWLRQLVGHULYHGGLUHFWO\IURPWKH DXWKRULWDWLYH1)+/ZHEVHUYLFHVSURYLGHGE\)(0$7KLVPDS ZDVH[SRUWHGRQ DWˇ˛˘˘30 DQGGRHVQRW UHIOHFWFKDQJHVRUDPHQGPHQWVVXEVHTXHQWWRWKLVGDWHDQG WLPH7KH1)+/DQGHIIHFWLYHLQIRUPDWLRQPD\FKDQJHRU EHFRPHVXSHUVHGHGE\QHZGDWDRYHUWLPH 7KLVPDSLPDJHLVYRLGLIWKHRQHRUPRUHRIWKHIROORZLQJPDS HOHPHQWVGRQRWDSSHDU˛EDVHPDSLPDJHU\IORRG]RQHODEHOV OHJHQGVFDOHEDUPDSFUHDWLRQGDWHFRPPXQLW\LGHQWLILHUV ),50SDQHOQXPEHUDQG),50HIIHFWLYHGDWH0DSLPDJHVIRU XQPDSSHGDQGXQPRGHUQL]HGDUHDVFDQQRWEHXVHGIRU UHJXODWRU\SXUSRVHV /HJHQG 27+(5$5($62) )/22'+$=$5' 27+(5$5($6 *(1(5$/ 6758&785(6 27+(5 )($785(6 0$33$1(/6 ˙ % 7KHSLQGLVSOD\HGRQWKHPDSLVDQDSSUR[LPDWH SRLQWVHOHFWHGE\WKHXVHUDQGGRHVQRWUHSUHVHQW DQDXWKRULWDWLYHSURSHUW\ORFDWLRQ ˛ˇ …:ˆ…˝˝1 …:ˆ…˙1 %DVHPDS,PDJHU\6RXUFH˛86*61DWLRQDO0DS Appendix A-5 9,0281505 City of Renton Aquifer Protection Zone WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 1023 0 512 1023 Feet 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. Legend Wellhead Protection Area Zones Zone 1 Zone 1 Modified Zone 2 Coalmines High Moderate Unclassified Erosion Hazard - High Landslide Very High High Moderate Unclassified 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 Streets 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 Appendix A-6 Downstream Analysis 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. Legend 1023 10230 1505 Feet 9,028 512 Pump Station Public Pump Station Private Pump Station Discharge Point Public Discharge Point Private Discharge Point Pipe Public Pipe Private Pipe Public Culvert Private Culvert Public Roofdrain Private Roofdrain Open Drains Facility Outline Vegetated Non-Vegetated Facility Transfer S 2ND ST 77 LF 24" DIA POLYETHYLENE PIPE 521 LF 30" DIA POLYPROPYENE PIPE 197 LF CONCRETE PIPE 364 LF 18" DIA DUCTILE PIPE 1/4 MILE POINT 633 LF 12" DIA POLYETHYLENE PIPE153 LF 12" DIA CONCRETE PIPE 514 LF 24" DIA POLYETHYLENE PIPE 343 LF 36" DIA POLYETHYLENE PIPE 1/4 MILE POINT OUTFALL TO CEDAR RIVER 510 LF CONCRETE PIPE C E D A R R I V E R C E D A R R I V E R LO G A N A V E S BU R N E T T A V E S MO R R I S A V E S SH A T T U C K A V E S S 3RD PL S 2ND ST SW S U N S E T B L V D R A I N I E R A V E S RA I N I E R A V E S LA K E A V E S S TOBIN ST S TILLICUM ST AIRPORT WAY S S 4TH PL S 4TH ST S 3RD ST S 3RD ST S 2ND ST PROJECT SITE 170 LF 36" DIA POLYPROPYENE PIPE APPENDIX A-7 TDA 1 TDA 2 TDA 3 4,514752 City of Renton Landslide Hazard Map WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 512 0 256 512 Feet 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. Legend Coalmines High Moderate Unclassified Erosion Hazard - High Landslide Very High High Moderate Unclassified 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 Streets 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 Appendix A-8 9,0281505 City of Renton Coal Mine Hazard Map WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 1023 0 512 1023 Feet 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. Legend Coalmines High Moderate Unclassified Streets 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 Appendix A-9 9,0281505 City of Renton Erosion Hazard Map WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 1023 0 512 1023 Feet 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. Legend Coalmines High Moderate Unclassified Erosion Hazard - High 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 Streets 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 Appendix A-10 4,514752 City of Renton Steep Slopes Map WGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 512 0 256 512 Feet 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. Legend Slope City of Renton >15% & <=25% >25% & <=40% (Sensitive) >40% & <=90% (Protected) >90% (Protected) Streets 2023.sid Red: Band_1 Green: Band_2 Blue: Band_3 Appendix A-11 10 0023 040054 0 203 01 100023040054020301 ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEAT ROW 3 SEAT BASIN 1 TDA 1 PERVIOUS 0.49 AC IMPERVIOUS 0.68 AC TOTAL AREA 1.17 AC UNDETAINED BASIN 2B TDA 2 PERVIOUS 1.06 AC IMPERVIOUS 5.61 AC TOTAL AREA 6.67 AC TO DETENTION TANK 2B BASIN 2A TDA 2 PERVIOUS 8.17 AC IMPERVIOUS 13.95 AC TOTAL AREA 22.12 AC UNDETAINED BASIN 3 TDA 3 PERVIOUS 1.15 AC IMPERVIOUS 5.69 AC TOTAL AREA 6.84 AC UNDETAINED NATURAL TURF FIELD ARTIFICIAL TURF FIELD WITH UNDERDRAINS ARTIFICIAL TURF FIELD WITH UNDERDRAINS ARTIFICIAL TURF FIELD WITH UNDERDRAINS 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL PROPOSED BASINS A-12 2230388.10 3/31/2026 LEGEND BASIN 1 - NO DETENTION N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 BASIN 2A - NO DETENTION BASIN 2B - TO TANK 2B BASIN 3 - NO DETENTION IMPERVIOUS SURFACE PAVEMENT IMPERVIOUS SURFACE ROOF IMPERVIOUS SURFACE FIELD WITH UNDERDRAINS PERVIOUS SURFACE LAWN DS DS DS DS DS DS DS DS DS DS DSDS DS DS DS DS DS DS DS DS DS DSDSDSDS DS DS DS DS DS DS DS DS DS DS DS DS DS DS ROW 1 SEATROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT ROW 1 SEAT ROW 2 SEAT ROW 4 SEATROW 3 SEAT 10 0023 040054 0 203 01 100023040054020301 74 8 8 S F 1493 SF 185 SF 341 SF 42 1 S F 52 4 S F 183 SF 462 SF 1294 SF 581 SF 152 SF 475 SF 62 0 3 S F 17 8 9 4 S F 2353 SF 202 SF 266 SF 429 SF 364 SF 330 SF 1103 SF 137 SF 463 SF 740 SF PLAYFIELD WITH NATURAL TURF, NO UNDERDRAINS PLAYFIELD WITH UNDERDRAINS PLAYFIELD WITH UNDERDRAINS PLAYFIELD WITH UNDERDRAINS 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL WATER QUALITY AREAS A-13 2230388.10 3/31/2026 LEGEND TARGET AREA TREATED N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 TARGET AREA NOT TREATED NON-TARGET AREA TREATED AREA EXCHANGE SUMMARY TARGET NOT TREATED 18,699 SF NON-TARGET TREATED 25,382 SF EXCESS TREATED 6,683 SF 692,635 SF 18,699 SF 25,382 SF NOTES 1.PLAY FIELDS WITH UNDERDRAINS ARE MODELED AS POLLUTANT GENERATING IMPERVIOUS SURFACE 10 0023 040054 0 203 01 100023040054020301 TREATMENT BASIN 6 PERVIOUS 0.24 AC IMPERVIOUS 1.85 AC TOTAL AREA 2.09 AC 0.1684 CFS OFF-LINE RATE TO BIOPOD 6 TREATMENT BASIN 3 PERVIOUS 1.57 AC IMPERVIOUS 6.20 AC TOTAL AREA 7.77 AC 0.5610 CFS OFF-LINE RATE TO FILTERRA 3 TREATMENT BASIN 4 PERVIOUS 0 AC IMPERVIOUS 2.72 AC TOTAL AREA 2.72 AC 0.2497 CFS OFF-LINE RATE TO FILTERRA 4 TREATMENT BASIN 5 PERVIOUS 0.00 AC IMPERVIOUS 0.25 AC TOTAL AREA 0.25 AC 0.0229 CFS OFF-LINE RATE TO BIOPOD 5 TREATMENT BASIN 7 PERVIOUS 0.24 AC IMPERVIOUS 0.58 AC TOTAL AREA 0.82 AC 0.0521 CFS OFF-LINE RATE TO FILTERRA 7 TREATMENT BASIN 8 PERVIOUS 0.33 AC IMPERVIOUS 1.02 AC TOTAL AREA 1.35 AC 0.0920 CFS OFF-LINE RATE TO FILTERRA 8 TREATMENT BASIN 2 PERVIOUS 0 AC IMPERVIOUS 1.91 AC TOTAL AREA 1.91 AC 0.1753 CFS OFF-LINE RATE TO FILTERRA 2 TREATMENT BASIN 1 PERVIOUS 0.59 AC IMPERVIOUS 1.73 AC TOTAL AREA 2.32 AC 0.1559 CFS OFF-LINE RATE TO BIOPOD 1 TREATMENT BASIN 9 PERVIOUS 1.82 AC IMPERVIOUS 1.91 AC TOTAL AREA 3.73 AC 0.1718 CFS OFF-LINE RATE TO FILTERRA 9 TREATMENT BASIN 10 PERVIOUS 0 AC IMPERVIOUS 0.25 AC TOTAL AREA 0.25 AC 0.0229 CFS OFF-LINE RATE TO BIOPOD 10 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL WATER QUALITY BASINS A-14 2230388.10 3/31/2026 N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 BIOPODS NUMBER FLOWRATE (CFS)BIOPOD CHOSEN BIOPOD TREATMENT CAPACITY (CFS) 1 0.1559 6x12 0.213 5 0.0229 4x4 0.029 6 0.1684 6x12 0.213 10 0.0229 4x4 0.029 ALL BIOPOD UNITS SIZED FOR ENHANCED BASIC TREATMENT PER WSDOE GULD APPROVAL FILTERRAS NUMBER FLOWRATE (CFS) TREATMENT AREA REQUIRED (SF)AREA PROVIDED 2 0.1753 23.37 6x4 = 24 SF 3 0.5610 74.80 8x10.5 = 84 SF 4 0.2497 33.29 6x6 = 36 SF 7 0.0521 6.95 4x4 = 16 SF 8 0.0920 12.27 4x4 = 16 SF 9 0.1718 22.91 6x4 = 24 SF ALL FILTERRA UNITS SIZED FOR ENHANCED BASIC TREATMENT AT 324 IN/HOUR PER WSDOE GULD APPROVAL TREATMENT BASIN SUMMARY NUMBER FLOWRATE (CFS)PROJECT PHASE DEVICE CHOSEN 1 0.1559 1 BIOPOD 2 0.1753 2 FILTERRA 3 0.5610 2 FILTERRA 4 0.2497 2 FILTERRA 5 0.0229 1 BIOPOD 6 0.1684 1 BIOPOD 7 0.0521 2 FILTERRA 8 0.0920 2 FILTERRA 9 0.1718 2 FILTERRA 10 0.0229 2 BIOPOD Technical Information Report New Renton High School Project No. 2230388.10 Appendix B Geotechnical Report B-1 .................... Geotechnical Engineering Report dated September 3, 2025 B-2 .................... Geotechnical Letter dated January 9, 2026 associated earth sciences incorporated Associated Earth Sciences, Inc. www.aesgeo.com Kirkland | Mount Vernon | Tacoma Subsurface Exploration, Geologic Hazard, and Geotechnical Engineering Report RENTON HIGH SCHOOL REPLACEMENT Renton, Washington Prepared For: RENTON SCHOOL DISTRICT NO. 403 Project No. 20210249E002 September 3, 2025 Kirkland | Tacoma | Mount Vernon 425-827-7701 | www.aesgeo.com September 3, 2025 Project No. 20210249E002 Renton School District No. 403 7812 South 124th Street Seattle, Washington 98178 Attention: Brianne Tomlin Subject: Subsurface Exploration, Geologic Hazard, and Geotechnical Engineering Report Renton High School Replacement 400 South 2nd Street Renton, Washington Dear Brianne Tomlin: We are pleased to present our geotechnical engineering report for the proposed Renton High School campus replacement project. This report serves as an update to our preliminary draft report, dated May 15, 2024, to reflect current design plans. This report summarizes the results of our subsurface explorations, geologic hazard, and geotechnical engineering studies and offers design recommendations based on our present understanding of the project. Once project plans are finalized, we should review the plans and confirm or update our recommendations, where necessary. It should be noted that the subsurface explorations and analyses completed for this study were focused on the main school campus. Additional subsurface explorations and engineering studies will be completed for newly acquired properties located north of the campus prior to construction. We have enjoyed working with you on this study and are confident that the recommendations presented in this report will aid in the successful completion of your project. If you should have any questions or if we can be of additional help to you, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington ______________________________ G. Bradford Drew, P.E. Associate Engineer BD/ld – 20210249E002-007 SUBSURFACE EXPLORATION, GEOLOGIC HAZARD, AND GEOTECHNICAL ENGINEERING REPORT RENTON HIGH SCHOOL REPLACEMENT Renton, Washington Prepared for: Renton School District No. 403 7812 South 124th Street Seattle, Washington 98178 Prepared by: Associated Earth Sciences, Inc. 911 5th Avenue Kirkland, Washington 98033 425-827-7701 September 3, 2025 Project No. 20210249E002 Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 1 I. PROJECT AND SITE CONDITIONS 1.0 INTRODUCTION This report presents the results of Associated Earth Sciences, Inc.’s (AESI’s) subsurface exploration, geologic hazard, and geotechnical engineering study for the proposed replacement of the Renton High School campus in Renton, Washington. The site location is shown on the “Vicinity Map,” Figure 1. The approximate locations of explorations completed for this study are shown on the “Existing Site and Exploration Plan,” Figure 2, and the “Proposed Site and Exploration Plan,” Figure 3. Copies of the exploration boring logs and cone penetrometer test (CPT) results for this current study are included in Appendices A and B, respectively; copies of the logs for nearby historical explorations completed by AESI for previous studies are included in Appendix C; a groundwater hydrograph is presented in Appendix D; laboratory test results are included in Appendix E; our liquefaction analysis results are included in Appendix F; the results of a shear wave velocity survey completed at the school campus by the Washington Geological Survey (WGS) is attached in Appendix G; and the wellhead protection zone mapping of the project site and vicinity is included in Appendix H. 1.1 Purpose and Scope The purpose of this study was to provide subsurface soil and groundwater data to be utilized in the design of the project. Our study included reviewing available geologic literature, review of previous explorations completed at the site, advancing six exploration borings with three borings completed as groundwater level observation wells, advancing three CPTs, and performing a geologic study to assess the type, thickness, distribution, and physical properties of the subsurface sediments and shallow groundwater conditions across the project area. Geotechnical engineering studies were completed to determine the type of suitable foundations, allowable foundation soil bearing pressures, anticipated foundation settlements, drainage considerations, and stormwater infiltration feasibility. This report summarizes our current fieldwork and offers preliminary development recommendations based on our present understanding of the project. It should be noted that the subsurface explorations and analyses completed for this study were focused on the main school campus. Additional subsurface explorations and engineering studies will be completed for newly acquired properties located north of the campus prior to construction. A general assessment of the anticipated soils conditions and infiltration feasibility within the newly acquired properties to the north of the main school campus is discussed in Section 17.2 of this report. Our assessment is primarily based on recent site observations during the demolition of below-grade residential structures. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 2 1.2 Authorization Written authorization to proceed with this study was granted by Renton School District No. 403 by means of signed Purchase Order, dated February 29, 2024. Our work was completed in general accordance with our scope of work and cost proposal dated October 31, 2023. This report has been prepared for the exclusive use of Renton School District No. 403 and their agents for specific application to this project. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering and engineering geology practices in effect in this area at the time our report was prepared. No other warranty, express or implied, is made. 2.0 SITE AND PROJECT DESCRIPTION The project site is located at the existing Renton High School campus in Renton, Washington, and consists of a single 23-acre parcel (King County Parcel No. 0007200060). The existing school buildings are currently located near the center of the parcel and include several classroom buildings, a gymnasium, and a maintenance building to the northeast. A parking lot occupies the southeast corner of the parcel and a softball field occupies the northeast corner. Tennis courts and three baseball fields currently occupy the western half of the parcel and are divided from the school building by a two-lane access road that connects South 2nd Avenue to South Tobin Street. The parcels surrounding the campus to the east and north of the campus generally consist of residential single-family lots. The existing school buildings are mostly two-story structures, the exception being the maintenance building to the northeast. The original Renton High School building was constructed in 1911 and replaced in 1932. Portions of the building were demolished and reconstructed in 1941. The school was then remodeled in 1969 and renovated in 1999. The 1999 renovation included the addition of the Performing Arts Center near the southeast corner of the site. The overall site topography is generally flat to very gently sloping to the northwest. Overall vertical relief across the school campus trending south to north is approximately 4 feet over a distance of about 850 feet. The Black River formerly passed through the project area along the western margin of the school campus, and the river channel onsite was filled after construction of the Ballard Locks in 1917. We understand that the existing buildings onsite are supported on deep foundations including augercast piles, driven pre-cast concrete piles, and timber piles. The project involves the significant replacement/renovation of the school campus and expansion to the north. Based on a design development plan set provided by BRIC Architecture, Inc., dated June 6, 2025, the campus replacement will include the following: Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 3 New school buildings surrounding the existing Performing Arts Center within the southeast corner of the campus and extending to the north toward South Tobin Street. New parking lots to the north and west of the 1930’s historical building. A new track and field area within the footprint of the existing baseball fields to the west. The addition (campus expansion) of new athletic fields to the north within the existing 7-acre residential block that is bounded by South Tobin Street to the south, Shattuck Avenue South to the west, Airport Way to the north, and Logan Avenue South to the east. The proposed site improvements are shown on Figure 3. We understand that all of the new athletic fields will be surfaced with synthetic turf and an underdrain system. No infiltration facilities are planned at this time. 3.0 SITE EXPLORATION Our field study for this phase of the project was completed in April 2024 and included advancing six exploration borings (EB-1 through EB-6W) across the eastern half of the school campus, with three borings completed as groundwater level observation wells (EB-1W, EB-3W, and EB-6W), to define the shallow groundwater conditions below the site. We also advanced three CPT probes (CPT-01 through CPT-03) to supplement the boring information and for use in our liquefaction analysis. The exploration locations are shown on the “Existing Site and Exploration Plan,” Figure 2, and the “Proposed Site and Exploration Plan,” Figure 3. The various types of sediments, as well as the depths where characteristics of the sediments changed, are indicated on the exploration logs presented in Appendix A. The depths indicated on the logs where conditions changed may represent gradational variations between sediment types in the field. The locations of our field explorations were determined by approximate measurements from known site features. The conclusions and recommendations presented in this report are based, in part, on the exploration borings completed for this study. The number, locations, and depths of the explorations were completed within site and budgetary constraints. Because of the nature of exploratory work below ground, extrapolation of subsurface conditions between field explorations is necessary. It should be noted that differing subsurface conditions might sometimes be present due to the random nature of deposition and the alteration of topography by past grading and/or filling. The nature and extent of variations between the field explorations may not become fully evident until construction. If variations are observed at that time, it may be necessary to re-evaluate specific recommendations in this report and make appropriate changes. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 4 3.1 Exploration Borings The exploration borings were completed by Advance Drill Technologies, Inc., an independent driller working under subcontract to AESI, by advancing a 6-inch outside-diameter, hollow-stem auger with a track-mounted drill rig. During the drilling process, samples were generally obtained at 2½- to 5-foot-depth intervals. As the borehole advanced below the water table, the driller added drilling fluid and water within the hollow-stem auger to help maintain borehole stability. After drilling, each borehole was backfilled with bentonite grout in combination with bentonite chips, and the surface was patched using turf in existing landscape areas and cold-mix asphalt patch in existing pavement areas. Disturbed, but representative samples were obtained by using the Standard Penetration Test (SPT) procedure in accordance with ASTM International (ASTM) D-1586. This test and sampling method consists of driving a standard 2-inch, outside-diameter, split-barrel sampler a distance of 18 inches into the soil with a 140-pound hammer free-falling a distance of 30 inches. The number of blows for each 6-inch interval is recorded, and the number of blows required to drive the sampler the final 12 inches is known as the Standard Penetration Resistance (“N”) or blow count. If a total of 50 is recorded within one 6-inch interval, the blow count is recorded as the number of blows for the corresponding number of inches of penetration. The resistance, or N-value, provides a measure of the relative density of granular soils or the relative consistency of cohesive soils; these values are plotted on the attached exploration boring logs. The borings were continuously observed and logged by a geologist from our firm. The samples obtained from the split-barrel sampler were classified in the field and representative portions placed in watertight containers. The samples were then transported to our laboratory for further visual classification and laboratory testing. The exploration logs presented in Appendix A are based on the N-values, field observations, and drilling action. 3.2 Exploration Borings Completed as Observation Wells Three of the exploration borings (EB-1W, EB-3W, and EB-6W) were completed as 2-inch-diameter groundwater level observation wells. These wells were installed to allow for monitoring of seasonal groundwater levels. The wells were constructed with 10 feet of machine-slotted Schedule 40 polyvinyl chloride (PVC) well screen, solid, non-slotted, Schedule 40 PVC casing, and a flush monument. The well screen interval and approximately 3 feet of the annular space above each well screen was backfilled with filter sand. The wells were completed with a bentonite surface seal, a flush-mount well cover set in concrete, and a locking well cap. Well construction details are presented on the geologic and well construction logs for EB-1W, EB-3W, and EB-6W in Appendix A. Groundwater levels ranged from approximately 11.8 to 14.3 feet below the existing ground surface at the time of installation. Well EB-6W was developed on April 26, 2024, and EB-1W and EB-3W were developed on April 29, 2024. After well development, the static water level was measured at about 9.5 feet below existing grade within EB-1W, 12.1 feet within Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 5 EB-3W, and 14.1 feet within EB-6W. Site hydrology is discussed in further detail in Section 4.4 of this report. 3.3 Cone Penetrometer Tests CPT probes CPT-01, CPT-02, and CPT-03 were performed by In Situ Engineering, working under subcontract to AESI, by pushing a 1.5-inch-diameter instrumented cone into the soil. The cone is instrumented with pressure transducers at the tip of the cone and along the sleeve of the cone to measure pressure and frictional resistance as the cone is pushed into the soil. Cone tip and sleeve resistance readings, as well as a pore water pressure transducer, provide a continuous record of the soil properties. This information can then be used to characterize soil type, density, and pore water pressure estimates, and support detailed soil liquefaction analysis and soil properties for ground improvement design. In addition, shear wave velocities were measured at approximate 3- to 6-foot-depth intervals at CPT-02. CPT-01, CPT-02, and CPT-03 were advanced to depths of 34 feet, 25 feet, and 20.5 feet below the existing ground surface, respectively, before encountering “refusal” likely due to an elevated gravel content or larger gravel-sized particles. The CPT logs are presented in Appendix B. 4.0 SUBSURFACE CONDITIONS Subsurface conditions at the project site were inferred from the field explorations accomplished for this study, visual reconnaissance of the site, and review of applicable geologic literature. The following sections describe observed site stratigraphy, regional geology, and local groundwater. The near-surface sediments encountered in our explorations generally consisted of existing fill overlying Holocene alluvial (river-deposited) sediments. The following section presents more detailed subsurface information organized from the shallowest (youngest) to the deepest (oldest) sediment types. 4.1 Stratigraphy The following subsections summarize our observations and interpretations of different sedimentary units observed in subsurface explorations in order of deposition from most recent to oldest. Asphalt Explorations EB-1W and EB-5 were located in the existing asphalt parking lots. Both explorations encountered about 3 inches of asphalt at the pavement surface. We did not observe any crushed rock base course material directly underlying the asphalt within EB-1W. We observed approximately 4 to 6 inches of crushed rock base course directly below the asphalt within EB-5. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 6 Fill Existing fill soils (those not naturally deposited) were encountered directly below the ground surface within each of the exploration borings completed for this study. The fill generally consisted of slightly moist to moist, very loose to medium dense, brown to dark brown, silty fine to medium sand with variable gravel content and scattered to abundant organics (roots, rootlets, wood debris, and fine organics). Observed fill depths within EB-1W through EB-5 ranged from approximately 3.5 to 4.5 feet below the existing ground surface. The deepest fill was observed in EB-6W and extended to about 7 feet below the existing ground surface. The existing fill is not considered suitable for foundation support and warrants assessment and possible remedial preparation at the time of construction where pavements and flat work are planned. Excavated existing fill material is suitable for reuse in structural fill applications if such reuse is specifically allowed by project plans and specifications, if excessively organic and any other deleterious materials are removed, and if moisture content is adjusted to allow compaction to the specified level and to a firm and unyielding condition. Existing fill is not considered suitable as an infiltration receptor for stormwater. Holocene Alluvium - Black River Alluvium Directly below the existing fill within EB-1W through EB-5, we encountered a generally fine-grained deposit of interbedded fine sand and silt, interpreted to be representative of alluvial sediments associated with the Black River, which historically crossed the site. This deposit contained loose to medium dense, sand with variable silt content ranging from some silt to silty and trace to some gravel, ranging to soft silt and sandy silt. These alluvial sediments were deposited from low-energy flowing water and are relatively loose/soft. No Black River alluvium was encountered in EB-6. Holocene Alluvium - Cedar River Alluvium Sediments encountered below the Black River alluvium within EB-1W through EB-5, and beneath the existing fill in EB-6W, generally consisted of medium dense, gray to brownish gray, sand, gravelly sand ranging to sandy gravel. We interpret these sediments as alluvial and deltaic sediments associated with the Cedar River. These sediments occasionally displayed stratification and contained rare organics (wood debris). We infer that the N-values indicating a dense condition were overstated due to an elevated gravel content. For geotechnical considerations, the Cedar River alluvium is in a medium dense condition. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 7 4.2 Previous Explorations and Studies Previous explorations and geotechnical studies were completed at the school campus by AESI in 1999, 2009, 2024, and April 2025, which included several borings and test pits in the vicinity of the proposed site improvements. The approximate locations of the previous explorations are shown on Figures 2 and 3, and copies of the exploration logs are included in Appendix C. On Figures 2 and 3, we have modified the exploration numbering system for these previous studies to include the year they were completed (e.g., EB-1-99) to avoid confusion with our current exploration numbering system. The previous studies included the following explorations: 4 borings (EB-1 through EB-4, completed March 1999) located around the perimeter of the Performing Arts Center on the south-central portion of the existing campus. These borings were advanced to depths ranging from 31.5 to 41.5 feet below existing site grades and encountered a surficial layer of fill underlain by alluvial sediments to the boring termination depth. Groundwater levels at the time of drilling ranged from about 4.5 to 12 feet below existing site grades. 4 test pits (EP-1 through EP-4, completed March 1999) located along the southern and western margins of the main school building to evaluate the type and condition of existing pile foundations. The pits were advanced to depths ranging from 5.5 to 11 feet below existing site grades and encountered a surficial layer of fill underlain by alluvial sediments. Groundwater seepage was encountered at about 11 feet at the time of excavation. Explorations EP-1 and EP-4 each exposed one treated timber pile beneath a perimeter foundation element, and explorations EP-2 and EP-3 each exposed one precast concrete pile. Our observations of the piles at the time of exposure are summarized below. Timber Pile Observations: At explorations EP-1 and EP-4, the general configuration of the foundation system included a foundation wall, with a relatively wider grade beam at the base, supported by timber piles connected to the bottom of the grade beams. Measurement of the pile diameters with a hand-held tape measure indicated pile butt diameters immediately beneath the grade beam connection of approximately 12 to 13 inches. We also used an increment borer to core a 0.2-inch-diameter sample of each timber pile. The cores indicated that the distance from edge to center of the piles was 6 to 6¼ inches, and that the depth of penetration of creosote treatment varied from about 0.3 to 0.7 inch. In general, the wood cores recovered from the piles appeared firm, sound, and free from visible weakness. Based on conventional estimates of Douglas Fir timber piles, namely tapering by 1 inch in diameter per 10 feet of length, and assuming a tip diameter of 9 inches, we estimated the pile lengths were on the order of 25 to 30 feet below the grade beams. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 8 Precast Concrete Pile Observations: At explorations EP-2 and EP-3, we observed the concrete piles had an octagonal cross-section. The piles were located beneath a grade beam in the case of EP-2, and beneath a pile cap in the case of EP-3. The piles generally appeared symmetrical; however, it was typically only possible to measure the diameter in the orientation parallel to the edge of the grade beam or pile cap. Each of the exposed piles measured approximately 13 inches from face to face of the octagonal cross-section in the direction parallel to the grade beam or pile cap. There was no means to determine the length of the concrete piles at the time of exploration. Two additional test pits (EP-1 and EP-2, completed in July 2024) were excavated along the western side of the 1930’s historical building to aid us in making additional observations of the existing precast concrete piles. EP-1 and EP-2 were located near the southwest corner and midpoint of the building’s western exterior, respectively. One pile and connecting grade beam were exposed at each location. Each pile exposed consisted of a precast concrete pile with an irregular octagonal cross-section approximately 13 inches wide. Each pile was observed to be in good condition with no obvious signs of deterioration, cracking, or spalling. Additional information related to our pile observations is contained in a letter-report, titled “Existing Pile Observations and Estimated Capacities, Renton High School Replacement, Renton Washington,” dated August 22, 2024. 14 borings (EB-1 through EB-14, completed December 2009) located across the existing athletic fields within the western half of the campus. Borings EB-1 through EB-6 were advanced to a depth of about 36.5 feet below site grade, and borings EB-7 through EB-14 were advanced to about 6.5 feet below existing site grades. These borings generally encountered a surficial layer of fill underlain by alluvial sediments to the boring termination depth. The alluvial sediments generally graded from loose to dense with depth, although we infer that the N-values indicating a dense condition were overstated due to an elevated gravel content. Groundwater levels at the time of drilling ranged from about 7 to 10 feet below existing site grades. AESI observed and documented three separate attempts to advance vertical boreholes and install geothermal test loops (GTLs) in areas within/near the school campus that were under consideration for the installation of production loop fields. The test loop boreholes were labeled GTL-1 through GTL-3 and their approximate locations are shown on Figures 2 and 3. Overall, the alluvial sediments below the site were observed to contain zones of gravel and possible cobbles and/or boulders that could significantly delay progress during production drilling and/or result in shallow termination/abandonment of boreholes. There appears to be a considerable risk in pursuing a production loop field at the school campus due the highly variable and complex geologic setting. We understand that a production loop field is no longer under consideration at this time. Additional information regarding the geothermal drilling observations and test loop attempts are Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 9 provided in a letter-report, titled “Thermal Conductivity Borings and Test Loop Installation, Renton High School Replacement, Renton, Washington,” dated April 25, 2025. In addition to previous work completed by AESI, the WGS completed a subsurface shear wave transmission velocity survey at the site in October 2020. The results of the survey are discussed further in the “Ground Motion/Seismic Site Class” section of this report and attached in Appendix G. The historical boring information and shear wave velocity survey were used to supplement the subsurface information obtained for this current study and to formulate preliminary recommendations for the design and development of the project. 4.3 Regional Geologic and Soils Mapping Review of the geologic map of the project area (Geologic Map of the Renton Quadrangle, King County, Washington, U.S. Geological Survey, Geologic Quadrangle Map GQ-405, by D.B. Mullineaux, [1965]) indicates that the site is expected to be underlain by modified land. Our interpretation of the sediments encountered in our recent explorations is in general agreement with the regional geologic map in that we encountered a layer of fill overlying native Holocene alluvial sediments, which is consistent with the history of the project area. The Black River previously crossed the western margin of the school campus and after construction of the Ship Canal and Ballard Locks, the Black River channel onsite was filled. Review of the regional soils mapping (Soil Survey of King County Area, Washington, U.S. Department of Agriculture [USDA], Soils Conservation Service [SCS] now referred to as Natural Resources Conservation Service [NRCS]) on the NRCS Web Soil Survey indicates that the subject site is underlain by Urban Land (Ur). Urban Land is soil that has been modified by disturbance of the natural layers with additions of fill material several feet thick. Our observations of the near-surface sediments encountered in our explorations are in general agreement with the soils mapping. 4.4 Hydrology Groundwater was encountered within the alluvial sediments in all six of the explorations completed for this study. The approximate depths to groundwater at the time of drilling along with post-development static water levels within the borings completed as wells (EB-1W, EB-3W, and EB-6W) are depicted on the subsurface exploration logs in Appendix A and summarized in Table 1 below. AESI has monitored seasonal groundwater levels within the on-site wells (EB-1W, EB-3W, and EB-6W) starting from well development in April 2024 through June 25, 2025. A hydrograph illustrating approximate groundwater elevations and precipitation amounts over time is presented in Appendix D. During this monitoring period, groundwater elevations have ranged from about 20 to 22 feet in August/September 2024 (seasonal low) to about 23.5 to 26 feet in Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 10 late March/early April 2025 (seasonal high), corresponding to seasonal fluctuations of 3 to 4 feet. The shallowest depth to water was measured in EB-1W; water levels were on the order of 6 feet below ground surface at this location in late March 2025. At the time of this report, the well locations and elevations have not been established by an optical survey. Once surveyed, the groundwater elevation at each well location can be established. The groundwater observed at these boring locations is interpreted to be representative of the localized unconfined aquifer underlying the site within the alluvial deposits. Perched groundwater may also be present within the fill at the contact with the finer-grained Black River alluvium, particularly after large storm events or near existing utility backfill. At the locations of EB-2, EB-4, and EB-5, groundwater was encountered and measured at the time of drilling within the Black River alluvial sediments at depths of 13.3, 14.1, and 10 feet below existing grade, respectively. The wells within EB-1W and EB-3W were developed on April 29, 2024, and the static water level was measured at about 9.5 feet and 12.1 feet below existing grade, respectively. The well within EB-6W was developed on April 26, 2024, and the static water level was measured at about 14.1 feet below existing grade. It should be noted that groundwater conditions can vary considerably across short distances, and fluctuations in groundwater conditions may occur due to the time of the year, on- and off-site land use, and variations in the amount of rainfall. Table 1 Summary of Observed Groundwater Levels at Time of Drilling and Seasonal High Groundwater Exploration Boring No. Depth to Groundwater(1) (feet) Water-Bearing Unit Interpretation EB-1W 11.8 ATD(2) 5.9 Seasonal High(3) Black River Alluvium Localized Unconfined Aquifer EB-2 13.3 ATD Black River Alluvium Localized Unconfined Aquifer EB-3W 13.6 ATD 10.7 Seasonal High Black River Alluvium Localized Unconfined Aquifer EB-4 14.1 ATD Black River Alluvium Localized Unconfined Aquifer EB-5 10 ATD Black River Alluvium Localized Unconfined Aquifer EB-6W 14.3 ATD 12.6 Seasonal High Cedar River Alluvium Localized Unconfined Aquifer (1) Groundwater depths correspond to depth below the existing ground surface. (2) ATD = At Time of Drilling (April 9-11, 2024). (3) Seasonal high groundwater level corresponds to measurements made in late March/early April 2025. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 11 Historical Groundwater Levels Historical explorations at the site have indicated groundwater levels as shallow as 4.5 feet at the time of drilling in early March. The approximate depths to groundwater at the time of drilling during previous studies at the site are summarized in Table 2 below. Table 2 Summary of Historical Groundwater Levels at Time of Drilling Exploration Boring No. Depth to Groundwater(1) (feet) At Time of Drilling Date Water-Bearing Unit Interpretation EB-1-09 7 12/22/2009 Black River Alluvium Localized Unconfined Aquifer EB-2-09 10 12/22/2009 Cedar River Alluvium Localized Unconfined Aquifer EB-3-09 8 12/22/2009 Black River Alluvium Localized Unconfined Aquifer EB-4-09 8 12/22/2009 Black River Alluvium Localized Unconfined Aquifer EB-5-09 9.5 12/22/2009 Black River Alluvium Localized Unconfined Aquifer EB-6-09 10 12/23/2009 Black River Alluvium Localized Unconfined Aquifer EB-1-99 ~4.5 3/11/1999 Recent Alluvium Localized Unconfined Aquifer EB-2-99 4.5 3/11/1999 Recent Alluvium Localized Unconfined Aquifer EB-3-99 12 3/11/1999 Recent Alluvium Localized Unconfined Aquifer EB-4-99 12.5 3/11/1999 Recent Alluvium Localized Unconfined Aquifer (1) Groundwater depths correspond to depth below the existing ground surface. 4.5 Laboratory Testing Grain-Size Analysis AESI performed eight grain-size analyses (sieves) on selected soil samples of the existing fill and native alluvial sediments to support soil classification in the field and to aid us in evaluating the suitability of the materials for potential reuse as structural fill, and to aid our liquefaction analysis. The laboratory test results are summarized in Table 3 below (and attached in Appendix E) with soil descriptions based on the ASTM D-2487 Unified Soil Classification System (USCS). Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Project and Site Conditions September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 12 Table 3 Summary of Laboratory Test Results Exploration Boring No. Sample Depth (feet) Geologic Unit USCS Soil Description Fines Content (%) EB-1W 5 Black River Alluvium Sandy SILT, trace gravel (ML) 71.2 EB-1W 35 Cedar River Alluvium SAND, some gravel, some silt (SP-SM) 5.5 EB-2 2.5 Fill Silty SAND, some gravel (SM) 23.2 EB-3W 2.5 Fill Silty SAND, some gravel (SM) 24.7 EB-3W 7.5 Black River Alluvium Very silty SAND, trace gravel (SM) 37.6 EB-4 0 Fill Very gravelly, silty, SAND (SM) 13.5 EB-5 10 Black River Alluvium Silty SAND (SM) 17.6 EB-6W 15 Cedar River Alluvium Very sandy GRAVEL, some silt (GP-GM) 5.7 USCS = Unified Soil Classification System Fines Content % = percent of total weight passing the U.S. No. 200 Sieve Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 13 II. GEOLOGIC HAZARDS AND CRITICAL AREAS The following discussion of potential geologic hazards and critical areas at the site and vicinity is based on the geologic conditions as observed and discussed herein. 5.0 LANDSLIDE HAZARDS AND MITIGATIONS Topography across the subject site and surrounding area is relatively flat to very gently sloping to the northwest. Overall vertical relief across the school campus trending south to north is approximately 4 feet over a distance of about 850 feet. We did not identify any steep slopes within the project site or vicinity. Due to the relatively flat topography across the project site and the lack of any sloping areas in the site vicinity, it is our opinion that the risk of landsliding affecting the school campus and adjacent properties is very low and that no mitigation measures are necessary for this project. 6.0 SEISMIC HAZARDS AND MITIGATIONS The following discussion is a general assessment of seismic hazards that is intended to be useful to the project design team in terms of understanding seismic issues, and to the structural engineer for design. All of Western Washington is at risk of strong seismic events resulting from movement of the tectonic plates associated with the Cascadia Subduction Zone (CSZ), where the offshore Juan de Fuca plate subducts beneath the continental North American plate. The site lies within a zone of strong potential shaking from subduction zone earthquakes associated with the CSZ. The CSZ can produce earthquakes up to magnitude 9.0, and the recurrence interval is estimated to be on the order of 500 years. Geologists infer the most recent subduction zone earthquake occurred in 1700 (Goldfinger et al., 20121). Three main types of earthquakes are typically associated with subduction zone environments: crustal, intraplate, and interplate earthquakes. Seismic records in the Puget Sound region document a distinct zone of shallow crustal seismicity (e.g., the Seattle Fault Zone [SFZ]). These shallow fault zones may include surficial expressions of previous seismic events, such as fault scarps, displaced shorelines, and shallow bedrock exposures. The shallow fault zones typically extend from the surface to depths ranging from 16 to 19 miles. A deeper zone of seismicity is associated with the subducting Juan de Fuca plate. Subduction zone seismic events produce intraplate earthquakes at depths ranging from 25 to 45 miles beneath the Puget Lowland including the 1949, 7.2-magnitude event; the 1965, 6.5-magnitude event; and the 2001, 1 Goldfinger, C., Nelson, C.H., Morey, A.E., Johnson, J.E., Patton, J.R., Karabanov, E., Gutierrez-Pastor, J., Eriksson, A.T., Gracia, E., Dunhill, G., Enkin, R.J., Dallimore, A., and Vallier, T., 2012, Turbidite Event History—Methods and Implications for Holocene Paleoseismicity of the Cascadia Subduction Zone: U.S. Geological Survey Professional Paper 1661–F, 170. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 14 6.8-magnitude event) and interplate earthquakes at shallow depths near the Washington coast including the 1700 earthquake, which had a magnitude of approximately 9.0. The 1949 earthquake appears to have been the largest in this region during recorded history and was centered in the Olympia area. Evaluation of earthquake return rates indicates that an earthquake of the magnitude between 5.5 and 6.0 is likely within a given 20-year period. Generally, there are four types of potential geologic hazards associated with large seismic events: 1) surficial ground rupture, 2) seismically induced landslides or lateral spreading, 3) liquefaction, and 4) ground motion. The potential for each of these hazards to adversely impact the proposed project is discussed below. 6.1 Surficial Ground Rupture Seattle Fault Zone The site is located approximately 3 miles south of the mapped limits of the SFZ. The SFZ is a broad east-west oriented zone that extends from approximately Issaquah to Alki Beach and is approximately 2.5 to 4 miles in width from north to south. The SFZ is speculated to contain multiple distinct fault “strands,” some of which are well understood and some of which may be poorly understood or unknown. Mapping of individual fault strands is imprecise, as a result of pervasive modification of the land surface by development, which has obscured possible surficial expression of past seismic events. Studies by the U.S. Geological Survey (USGS) and others have provided evidence of surficial ground rupture along strands of the Seattle Fault (USGS, 20102; Pratt et al., 20153; Haugerud, 20054; Liberty et al., 20085). According to USGS studies the latest movement of this fault was about 1,100 years ago when about 20 feet of surficial displacement took place. This displacement can presently be seen in the form of raised, wave-cut beach terraces along Alki Point in West Seattle and Restoration Point at the south end of Bainbridge Island. Based on our review of the Washington State Department of Natural Resources (WADNR) website, inferred fault traces associated with the SFZ are located about 3 miles north of the site. Existing fault studies in the project area are insufficient to draw strong conclusions regarding seismic surface rupture potential at the project site. Due to the fact that the nearest mapped potential fault traces are located approximately 3 miles away from the site, and due to the suspected recurrence interval of seismic events along the SFZ, the potential for seismic surface rupture at the site is considered to be low during the expected life of the proposed structures, in our opinion. 2 U.S. Geological Survey, 2010, Quaternary Fault and Fold Database for the United States, accessed November 10, 2010, from USGS web site: http://earthquake.usgs.gov/hazards/qfaults/. 3 Pratt et al., 2015, Kinematics of Shallow Backthrusts in the Seattle Fault Zone, Washington State: Geosphere, v. 11, no. 6, p. 1-27). 4 Haugerud, R.A., 2005, Preliminary Geologic Map of Bainbridge Island, Washington: U.S. Geological Survey Open-File Report 2005-1387, version 1.0, 1 sheet, scale 1:24,000. 5 Liberty, Lee M.; Pratt, Thomas L., 2008, Structure of the Eastern Seattle Fault Zone, Washington State - New insights from Seismic Reflection Data: Bulletin of the Seismological Society of America, v. 98, no. 4, p. 1681-1695. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 15 6.2 Seismically Induced Landslides It is our opinion that the potential risk of damage to the proposed development by seismically induced slope failures is low during a design-level seismic event due to the lack of slopes at the project site and vicinity. No detailed slope stability analysis was completed for this project, and none is warranted, in our opinion. 6.3 Liquefaction Liquefaction is a process through which unconsolidated soil loses strength as a result of vibrations, such as those which occur during a seismic event. During normal conditions, the weight of the soil is supported by both grain-to-grain contacts and by the fluid pressure within the pore spaces of the soil below the water table. Extreme vibratory shaking can disrupt the grain-to-grain contact, increase the pore pressure, and result in a temporary decrease in soil shear strength. The soil is said to be liquefied when nearly all of the weight of the soil is supported by pore pressure alone. Liquefaction can result in deformation of the sediment and settlement of overlying structures. Areas most susceptible to liquefaction include those areas underlain by very soft to stiff, non-cohesive silt and very loose to medium dense, non-silty to silty sands with low relative densities, accompanied by a shallow water table. To evaluate the extent of liquefaction risk and estimated settlement potential during a design-level seismic event, we performed a liquefaction hazard analysis utilizing data obtained from our exploration borings and CPTs. Our liquefaction analysis was completed with the aid of LiquefyPro computer software Version 5.9a (2015) by CivilTech Corporation. This program accepts input for SPT and CPT data, groundwater levels, soil unit weight, and the depth and grain-size distribution of the sediments of concern to calculate seismically induced settlement. The following parameters were used during the analysis: We assumed a seasonal high groundwater level of 5 feet below the existing ground surface during earthquake shaking; Soil unit weights were inferred from SPT and CPT data; Silt contents were inferred from CPT data and a combination of visual and laboratory classification of soil samples obtained from the SPT borings; CPT data were automatically normalized for overburden stresses and corrected for fines content and seismic magnitude by the LiquefyPro computer software; We used the Tokimatsu M-Correction analysis method in the LiquefyPro computer software to obtain the liquefaction-induced settlement values; A design event is considered a magnitude 7.0 earthquake with a peak horizontal ground acceleration of 0.677g as determined from the ASCE Hazard Tool website at https://ascehazardtool.org. The results of the liquefaction analysis indicate that the Black River alluvium and Cedar River alluvium are susceptible to liquefaction to a depth of about 40 feet and are predicted to Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 16 experience significant amounts of liquefaction-induced settlement during a design-level seismic event. Although Cedar River alluvium was encountered below a depth of 40 feet in all exploration borings, we assess that the liquefaction potential is low below this depth as the drill rig auger “refused” at a depth of about 45 to 50 feet at all locations, indicating the presence of large gravels/cobbles that would be considered non-liquefiable or the contact of a very dense geologic unit. This assessment is further supported by the shear wave velocity data obtained by the WGS (see Appendix G), where the measured shear wave velocities below a depth of 40 feet exceeded 1,200 feet per second, which corresponds to “very dense soil and soft rock” per ASCE 7-16 Table 20.3-1 “Site Classification.” The liquefaction-induced settlement calculated based on SPT data ranged from about 2 to 11 inches (with an average of 6 to 7 inches), and the magnitude of predicted settlement generally increased across the site trending south to north. We assess this trend in predicted settlement is correlated to the thickness of the Black River alluvium. As the thickness of the loose/soft Black River alluvial sediments “pinch out” toward the south end of the site, the magnitude of liquefaction-induced settlement decreases, suggesting that the magnitude of liquefaction- induced settlement can be expected to increase to the north. It should be noted that the magnitude of predicted settlements based on CPT data is significantly less than results based on SPT data. We attribute this discrepancy to the following: (1) the CPT- based analysis did not consider some of the gravelly layers liquefiable as the measured cone resistance was overstated and (2) soft silt layers within the Black River alluvium unit were correlated to a non-liquefiable clay. It is our opinion that the liquefaction analysis results based on SPT data are more representative of the subsurface conditions and liquefaction potential at the site. The results of our liquefaction analysis at individual exploration locations are summarized in Table 4 and details are presented in Appendix F. Table 4 Estimated Total Liquefaction-Induced Settlement Exploration Number Estimated Total Liquefaction-Induced Settlement (inches) EB-1W 11 EB-2 7 EB-3W 7 EB-4 7 EB-5 4 EB-6W 2 CPT-01 1.8 CPT-02 0.9 CPT-03 1.4 Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 17 Based on the results of the liquefaction analysis summarized above, it is our opinion that liquefaction mitigation measures are warranted for this project. Our design recommendations for ground improvement to mitigate liquefaction-induced settlement hazards are presented below in the “Foundations” section of this report. 6.4 Ground Motion/Seismic Site Class Based on the subsurface stratigraphy and visual reconnaissance of the site, it is our opinion that earthquake damage to the proposed structures when founded on suitable bearing strata in accordance with the recommendations contained herein, would likely be caused by the intensity and acceleration associated with the event. We understand that structural design for the project will follow the 2021 International Building Code (IBC) standards and the American Society of Civil Engineers Publication ASCE 7-16 Minimum Design Loads and Associated Criteria for Buildings and Other Structures. ASCE 7-16 allows a simplified procedure for determining site class for those projects where liquefiable-prone soils are present and the fundamental period of the planned building is 0.5 seconds or less. The simplified procedure allows the site class to be determined based on the average N-value and/or average shear wave velocity within the upper 100 feet of the site as outlined in ASCE 7-16 Section 20.3. If the fundamental period is greater than 0.5 seconds, we will need to perform a site-specific response analysis in accordance with ASCE 7-16, Sections 20.3.1 and 21.1. We are available to perform this analysis and reporting under a separate scope of work when a developed site plan is selected that includes building locations and heights. For proposed structures that will have a building period of less than 0.5 seconds, we recommend using Site Class D for structural design based on the subsurface conditions encountered in our exploration borings and the shear wave velocity data obtained by the WGS (as discussed below). As previously mentioned, the WGS conducted a seismic survey at the project site on October 15, 2020. The seismic survey was completed with an array of 48 geophones placed in a 308-foot line to measure the shear wave velocity within the upper 100 feet of soil. This array was located to the west of the existing school buildings in the existing ballfield. The average shear wave velocity within the upper 100 feet of the array was approximately 892 feet per second, which corresponds to Site Class D. The shear wave velocity results are included in Appendix G. 7.0 EROSION HAZARDS AND MITIGATIONS Erosion Hazards are defined in the Renton Municipal Code (RMC) Section 4-3-050G.5.c. as the following: Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 18 i. Low Erosion Hazard (EL): Areas with soils characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having slight or moderate erosion potential, and a slope less than fifteen percent (15%). ii. High Erosion Hazard (EH): Areas with soils characterized by the Natural Resource Conservation Service (formerly U.S. Soil Conservation Service) as having severe or very severe erosion potential, and a slope more than fifteen percent (15%). Based on our review of the City of Renton “Sensitive Areas Map: Erosion Hazard,” the subject site is not mapped as an erosion hazard area. As stated in the “Regional Geologic and Soils Mapping” section of this report, the site is identified as Urban Land. The NRCS indicates that the erosion hazard rating for Urban Land soils is slight to moderate. Due to the lack of slopes at the site and the erosion hazard rating of slight to moderate for on-site material, the subject site classifies as a Low Erosion Hazard according to the RMC. Despite being identified as a Low Erosion Hazard, the existing fill and underlying native alluvial sediments at the site generally contain significant quantities of silt and fine sand. These sediments will be susceptible to erosion and off-site sediment transport when exposed during construction. Therefore, the project should follow best management practices (BMPs) to mitigate erosion hazards and potential for off-site sediment transport. The Washington State Department of Ecology (Ecology) Construction Stormwater General Permit (also known as the National Pollutant Discharge Elimination System [NPDES] permit) requires weekly Temporary Erosion and Sedimentation Control (TESC) inspections and turbidity monitoring of site runoff for all sites that are 1 or more acres in size that discharge stormwater to surface waters of the state. The TESC inspections and turbidity monitoring of runoff must be completed by a Certified Erosion and Sediment Control Lead (CESCL) for the duration of the construction. Requirements for inspections, sampling, and reporting can be found in the Construction Stormwater General Permit online at ecology.wa.gov. In order to meet the current Ecology requirements, a properly developed, constructed, and maintained erosion control plan consistent with local standards and best management erosion control practices will be required for this project. It is often necessary to make adjustments and provide additional measures to the TESC plan in order to improve its effectiveness. Ultimately, the success of the TESC plan depends on a proactive approach to project planning and contractor implementation and maintenance. To mitigate and reduce the erosion hazard and potential for off-site sediment transport, we recommend the following: 1. Construction activity should be scheduled or phased as much as possible to avoid earthwork activity during the wet season. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 19 2. The winter performance of a site is dependent on a well-conceived plan for control of site erosion and stormwater runoff. The site plan should include ground-cover measures and staging areas. The contractor should be prepared to implement and maintain the required measures to reduce the amount of exposed ground. 3. TESC elements and perimeter flow control should be established prior to the start of grading. This should include, but is not limited to, silt fencing, swales with check dams, rocked construction entrance, etc. 4. During the wetter months of the year, or when significant storm events are predicted during the summer months, the work area should be stabilized so that if showers occur, it can receive the rainfall without excessive erosion or sediment transport. The required measures for an area to be “buttoned-up” will depend on the time of year and the duration that the area will be left unworked. During the winter months, areas that are to be left unworked for more than 2 days should be mulched or covered with plastic. During the summer months, stabilization will usually consist of seal-rolling the subgrade. Such measures will aid in the contractor’s ability to get back into a work area after a storm event. The stabilization process also includes establishing temporary stormwater conveyance channels through work areas to route runoff to the approved treatment/discharge facilities. 5. Surface runoff and discharge should be controlled during and following development. Uncontrolled discharge may promote erosion and sediment transport. 6. Soils that are to be reused around the site should be stored in such a manner as to reduce erosion from the stockpile. Protective measures may include, but are not limited to, covering stockpiles with plastic sheeting, or the use of silt fences around stockpile perimeters. It is our opinion that with the proper implementation of the TESC plans and by field-adjusting appropriate erosion mitigation (BMPs) throughout construction, the potential adverse impacts from erosion hazards on the project may be mitigated. 8.0 CRITICAL AQUIFER RECHARGE AREAS Based on our review of the City of Renton’s Water System Plan Update, A Comprehensive Water System Plan (May 2021), which is the guiding document for the aquifer protection zone mapping and regulations, Section 6.10 “Wellhead Protection Program” states the following: Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 20 “As part of its Aquifer Protection Program, the City has enacted aquifer protection regulations within the Aquifer Protection Areas (APAs) to protect the aquifers used as potable water supply sources from contamination by hazardous materials. The regulations include restrictions on hazardous material quantities, storage, and handling; land use restrictions; facility operating standards; construction activity standards; fill quality standards; and other measures intended to prevent contamination.” Based on our review of the City of Renton interactive online GIS mapping tool6, the existing high school campus and proposed expansion is located within a Wellhead Protection Area (WHPA). The GIS mapping indicates that the approximate eastern half of the school campus and proposed improvements are located within a Zone 1 WHPA and the approximate western half of the school campus and proposed improvements are located within a Zone 2 WHPA. The GIS mapping of the Zones 1 and 2 WHPAs relative to the school campus and proposed expansion is presented in Appendix H. Section 4-3-050G.8 of the RMC defines WHPAs as follows: 8. Wellhead Protection Areas: a. Applicability: Developments, facilities, uses and activities discussed in this subsection shall comply with the applicable provisions and restrictions of this Section and chapters 4-4, 4-5, 4-6, 4-9, and 5-5 RMC for the Wellhead Protection Areas, as classified below, in which the developments, facilities, uses and activities are located, except as preempted by Federal or State law. i. Wellhead Protection Areas: Wellhead Protection Areas are the portion of an aquifer within the zone of capture and recharge area for a well or well field owned or operated by the City. ii. Wellhead Protection Area Zones: Zones of a Wellhead Protection Area are designated to provide graduated levels of Wellhead Protection Area recharge. Zone boundaries are determined using best available science documented in the City of Renton Wellhead Protection Plan, an appendix of the City of Renton Water System Plan, as periodically updated. The following zones may be designated: (a) Zone 1: The land area situated between a well or well field owned by the City and the three hundred sixty five (365) day groundwater travel time contour. (b) Zone 1 Modified: The same land area described for Zone 1 but for the purpose of protecting a high-priority well, wellfield, or spring withdrawing from a confined aquifer with partial leakage in the overlying or underlying confining layers. Uses, activities, and facilities located in this area are regulated as if located within Zone 1 except as provided by this subsection G8. (c) Zone 2: The land area situated between the three hundred sixty five (365) day groundwater travel time contour and the boundary of the zone of potential capture for a well or well field owned or operated by the City. If the aquifer supplying water to such a well, well field, or spring is naturally protected by confining overlying and underlying geologic layers, the City may choose not to subdivide a Wellhead Protection Area into two (2) zones. In such a case, the entire Wellhead Protection Area will be designated as Zone 2. 6 https://www.rentonwa.gov/Projects-Development/Maps-and-GIS-Data Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 21 RMC Section 4-8-120 lists the submittal requirements for each type of permit application or land use approval, and RMC Section 4-8-120D, Table 18, lists the geotechnical reporting requirements for projects located within a regulated shoreline area, which includes sites located within WHPAs. The geotechnical reporting requirements contained in Table 18 that have not already been addressed in other sections of this report are provided below in italics along with our responses. Note that we have used the same name numbering scheme for the list of reporting requirements as Table 18. 4. Characterize groundwater conditions including the presence of any public or private wells within one- quarter (1/4) mile of the site. Groundwater conditions at the site are described in the “Hydrology” section of this report. AESI reviewed available information on WHPAs for Group A and Group B water systems located within ¼ mile of the subject site. Based on mapping by the Washington State Department of Health (DOH) Source Water Assessment Program (SWAP) application7, an inactive Group B well is located about 350 feet west of the western property line. No other wells were mapped within ¼ mile of the subject site. Based on our review of the Washington State Department of Ecology Well Construction & Licensing Map Search8, no water supply wells are located within ¼ mile of the subject site. 19. Address factors specific to the site, or to the proposed shoreline modification, as required in RMC 4-3- 090, Shoreline Master Program Regulations. RMC 4-3-090 is specific to shorelines of the State and does not directly address WHPAs; however, this section references RMC 4-3-050 which has been previously discussed above. Based on our review of the RMC and the City’s comprehensive water system plan, the following key items should be noted for this project: Stormwater infiltration is not allowed in a Zone 1 WHPA. Limitations apply to the conveyance, detention, and water quality of stormwater facilities to prevent infiltration. Liners may be required. Construction activity policies must be established for onsite re-fueling along with action plans/documentation protocols for incidents related to leaking fuel, hydraulic fluid, etc. Fill quality standards will apply to earthwork during construction. An imported fill source statement is required if more than 50 cubic yards (Zone 1) or 100 cubic yards (Zone 2) of imported fill will be brought to the site. 7 https://fortress.wa.gov/doh/swap/index.html 8 https://appswr.ecology.wa.gov/WellConstruction/ Map/WCLSWebMap/WellConstructionMapSearch.aspx Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Geologic Hazards and Critical Areas September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 22 In summary, based on known subsurface conditions and the current development plans, there are no indications that long-term groundwater levels or groundwater quality will be adversely impacted by the proposed high school replacement and expansion, provided the development utilizes modern stormwater management controls (BMPs) during construction and final development and City of Renton requirements for development in aquifer protection areas. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 23 III. DESIGN RECOMMENDATIONS 9.0 INTRODUCTION Our explorations indicate that, from a geotechnical engineering standpoint, the project is feasible provided the recommendations in this report are properly incorporated during design and construction. The explorations completed for this study indicate that the footprint of the school campus replacement contains a variable thickness of existing fill overlying loose to medium dense alluvial sediments accompanied by a shallow water table. Existing fill is not suitable for foundation support and warrants remedial preparation below pavements and flat work. The near-surface alluvial deposits are susceptible to liquefaction and will require mitigation measures for building foundation support. Based on explorations and analyses completed to date, we have identified the following geotechnical considerations that will impact design and construction of the project: Our liquefaction analysis predicts that the site may experience up to 11 inches of settlement during a design-level earthquake event, primarily due to liquefaction-induced settlement of the loose to medium dense alluvial sediments that extend to a depth of about 40 feet. This magnitude of settlement will require liquefaction mitigation measures such as ground improvement or a deep foundation system. Groundwater was encountered at depths ranging from about 9.5 to 14 feet at the time of our explorations. Our explorations for this study were conducted in April when groundwater levels are typically elevated but not at seasonal high levels. Previous explorations at the site have indicated groundwater levels as shallow as 4.5 feet at the time of drilling in early March. Depending on the time of construction, significant dewatering efforts may be required to control groundwater flow into excavations for utilities or other facilities deeper than about 5 feet. The following sections provide our recommendations for site preparation and earthwork, temporary cut slopes, structural fill, building foundations, floor support, drainage considerations, pavements, and infiltration feasibility. 10.0 SITE PREPARATION Prior to site work, erosion and surface water control should be established around the perimeter of the site to satisfy City of Renton and Ecology requirements, as discussed in the “Erosion Hazards and Mitigations” section of this report. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 24 10.1 Well Decommissioning Prior to construction, any wells that are located within the footprint of planned improvements (e.g., buildings, pavements, hardscapes, utilities, and athletic fields), or any wells that are no longer needed for groundwater level monitoring, should be decommissioned by a licensed well driller in accordance with Washington Administrative Code (WAC) 173-160-381. 10.2 Clearing and Stripping Existing buildings, foundations, pavements, buried utilities, vegetation, topsoil, and any other deleterious materials should be removed where they are located below planned construction areas. Any disturbed soils or depressions, such as those that may be caused by demolition activities, below planned final grades should be compacted with a smooth-drum vibratory roller to at least 95 percent of the modified Proctor maximum dry density as determined by the ASTM D-1557 test procedure, and to a firm and unyielding surface. Structural fill should be placed as needed to restore planned grades as discussed under the “Structural Fill” section of this report. Where excavated existing fill and native sediments are free of organics and near their optimum moisture content for compaction they can be segregated and considered for reuse as structural fill if allowed by project specifications. Most of the native sediments encountered in our explorations contained significant silt fractions and are considered highly moisture-sensitive; these soils may be difficult to reuse as structural fill. 10.3 Existing Fill After demolition, clearing, stripping, and any planned excavations have been completed, existing fill should be addressed within areas of planned paving and hardscapes. The existing fill should be exposed, compacted, and proof-rolled under the observation of AESI. Any areas that are soft, yielding, or contain excessive organic material or demolition waste should be corrected as needed prior to paving. 10.4 Temporary Cut Slopes In our opinion, stable construction slopes should be the responsibility of the contractor and should be determined during construction based on the conditions encountered at that time. For estimating purposes, however, we anticipate that temporary, unsupported cut slopes in unsaturated existing fill and native alluvial soils can be planned at inclinations of 1.5H:1V (Horizontal:Vertical) or flatter. Excavations below the groundwater table into saturated sediments should not be attempted without proper dewatering measures in place. Permanent cut or structural fill slopes should not be steeper than 2H:1V. Permanent slopes that will be exposed to surface water should be inclined at 3H:1V or flatter. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 25 These slope angles are for areas where groundwater seepage is not encountered and assume that surface water is not allowed to flow across the temporary slope faces. As is typical with earthwork operations, some sloughing and raveling may occur, and cut slopes may have to be adjusted in the field. In addition, WISHA/OSHA regulations should be followed at all times. 10.5 Site Disturbance The existing fill and native sediments contain a high percentage of fine-grained material. These sediments are considered to be highly moisture-sensitive and subject to disturbance when wet. The contractor must use care during site preparation and excavation operations so that the underlying soils are not softened. If disturbance occurs, the softened soils should be removed and the area brought to grade with structural fill. 10.6 Wet Weather Considerations The on-site soils are considered to be highly moisture-sensitive. If construction takes place in, during, or immediately following the wetter periods of the year, we anticipate the on-site soils will become unsuitable for structural fill applications. If earthwork will be completed during wet season months, we recommend budgeting to construct all structural fills with select, imported fill materials. For construction immediately following wet periods, significant, but unavoidable effort will be needed to scarify, aerate, and dry site soils to reduce moisture content prior to compaction in structural fill applications. Care should be taken to seal all earthwork areas during mass grading at the end of each workday by grading all surfaces to drain and sealing them with a smooth-drum roller. Stockpiled soils that will be reused in structural fill applications should be covered whenever rain is possible. Construction during extended wet weather periods could create the need to overexcavate exposed soils if they become disturbed and cannot be recompacted due to elevated moisture content and/or weather conditions. Even during dry weather periods, soft/wet soils may be encountered in some portions of the site that will require overexcavation. If overexcavation is necessary, it should be confirmed through continuous observation and testing by AESI. Soils that have become unstable may require remedial measures in the form of one or more of the following: 1. Drying and recompaction. Selective drying may be accomplished by scarifying or windrowing surficial material during extended periods of dry and warm weather. 2. Removal of affected soils to expose a suitable bearing subgrade and replacement with compacted structural fill. 3. Mechanical stabilization with a coarse crushed aggregate compacted into the subgrade, possibly in conjunction with a geotextile. 4. Soil/cement admixture stabilization. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 26 Consideration should be given to protecting access and staging areas with an appropriate section of crushed rock or asphalt treated base (ATB). If crushed rock is considered for the access and staging areas, it should be underlain by engineering stabilization fabric (such as Mirafi 500X or approved equivalent) to reduce the potential of fine-grained materials pumping up through the rock during wet weather and turning the area to mud. The fabric will also aid in supporting construction equipment, thus reducing the amount of crushed rock required. We recommend that at least 10 inches of rock be placed over the fabric. Crushed rock used for access and staging areas should be of at least 2-inch size. 11.0 STRUCTURAL FILL All new structural fill should be placed and compacted according to the recommendations presented in this section and requirements included in project specifications. All references to structural fill in this report refer to subgrade preparation, fill type, placement, and compaction of materials, as discussed in this section. If a percentage of compaction is specified under another section of this report, the value given in that section should be used. 11.1 Subgrade Compaction After clearing, stripping, and existing fill replacement have been completed in accordance with the “Site Preparation” section of this report, the upper 12 inches of exposed ground should be recompacted to a firm and unyielding condition. If the subgrade contains too much moisture, suitable recompaction may be difficult or impossible to attain and should probably not be attempted. In lieu of recompaction, the area to receive fill should be blanketed with washed rock or quarry spalls to act as a capillary break between the new fill and the wet subgrade. Where the exposed ground remains soft and further overexcavation is impractical, placement of an engineering stabilization fabric may be necessary to prevent contamination of the free-draining layer by silt migration from below. After recompaction of the exposed ground is tested and approved, or a free-draining rock course is laid, structural fill may be placed to attain desired grades. 11.2 Structural Fill Compaction Structural fill is defined as non-organic soil compliant with project specifications, placed in maximum 8-inch loose lifts, with each lift being compacted to at least 95 percent of the modified Proctor maximum dry density using ASTM D-1557 as the standard. The top of the compacted fill should extend horizontally a minimum distance of 3 feet beyond footings before sloping down at an angle no steeper than 2H:1V. Fill slopes should either be overbuilt and trimmed back to final grade or surface-compacted to the specified density. In the case of roadway and utility trench filling, the backfill should be placed and compacted in accordance with City of Renton standards. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 27 11.3 Use of On-Site Soils as Structural Fill Soils in which the amount of fine-grained material (smaller than No. 200 sieve) is greater than approximately 5 percent (measured on the minus No. 4 sieve size) should be considered moisture-sensitive. Most of the existing fill and near-surface native sediments encountered in our explorations contained significant silt fractions and are considered highly moisture-sensitive; these soils may be difficult to reuse as structural fill. Additionally, construction equipment traversing the site when the silty native sediments are very moist or wet can cause considerable disturbance. During the wetter portion of the year, typically from October to June, we recommend assuming that the on-site soils will not be suitable for reuse in structural fill applications. Possible alternatives would include cement treating on-site soils or using only a select import material consisting of a clean, free-draining gravel and/or sand. Free-draining fill consists of non-organic soil with the amount of fine-grained material limited to 5 percent by weight when measured on the minus No. 4 sieve fraction. 11.4 Structural Fill Testing The contractor should note that any proposed fill soils must be evaluated by AESI prior to their use in fills. This would involve providing us with a sample of the material at least 3 business days in advance to perform a Proctor test to determine its field compaction standard. A representative from our firm should observe the subgrades and be present during placement of structural fill to observe and document the work and perform a representative number of in-place density tests. In this way, the adequacy of the earthwork may be evaluated as filling progresses and any problem areas may be corrected at that time. Such testing and observation may be required by the City of Renton. 12.0 FOUNDATIONS Based on our review of the conceptual site plan, we understand that the campus replacement will include new school buildings surrounding the Performing Arts Center within the southeast corner of the campus. We anticipate that the foundation bearing soils within the proposed building footprints will generally be comprised of existing fill underlain by Black River and Cedar River alluvium. The alluvium within this current footprint of the new school buildings is predicted to experience liquefaction during a design-level seismic event, potentially resulting in average post-liquefaction total settlements on the order of 7 inches and differential settlements on the order of 5 inches. Given these conditions, it is our opinion that the existing site soils below the planned buildings are not suitable for the direct support of conventional shallow foundations. Additionally, we anticipate that the loose/soft alluvial sediments will result in excessive post-construction settlements under static loading. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 28 Due to the liquefaction hazards at the site, we recommend that buildings be supported on either shallow foundations utilizing ground improvement measures or deep foundations to mitigate excessive static settlement and differential liquefaction-induced settlement. Since ground improvement mitigates liquefaction hazards and is typically more economical than deep foundations, we consider shallow foundations with ground improvement to be the most cost-effective approach for this project. A ground improvement program consisting of vibratory stone columns or rammed aggregate piers (RAPs) is recommended to provide building foundation and slab-on-grade support. The ground improvement system would be designed by the ground improvement contractor to mitigate both static and seismic liquefaction settlements, and limit post-liquefaction differential settlements to structural design requirements. Subsequent to completion of the ground improvement program, the building could be supported using conventional spread footing foundations. The ground improvement contractor in conjunction with the project structural engineer should provide the final spacing, depths, and diameters of the RAPs. For project planning purposes, shallow foundations bearing on properly completed RAPs can typically be designed for an allowable soil bearing pressure ranging from 4,000 to 6,000 pounds per square foot (psf). Based on our initial discussions with the project team, we anticipate that RAPs will be spaced at approximate 6-foot centers below footings. The array of RAPs should maintain a minimum horizontal distance of 15 feet from the edge of any existing buildings to mitigate potential vibration-induced distresses on sensitive building elements. A vibration monitoring program should be established prior to construction in coordination with AESI. Given the magnitude of predicted liquefaction-induced settlement across the site (average total settlement of 7 inches and differential settlements on the order of 5 inches), we recommend that RAPs also be incorporated into the slab-on-grade design. We anticipate that RAPs below interior slabs would be spaced at approximate 8- to 10-foot centers. If significant damage and loss of functionality of interior slabs during an earthquake event is deemed acceptable by the District, a typical slab-on-grade could be used (4- to 6-inch concrete slab supported on a capillary break layer with vapor barrier); however, remediation of the loose existing fill soils will be required to mitigate static settlement. Remedial measures of existing fill would involve up to 2 feet of overexcavation and replacement with select imported structural fill or crushed rock. Overexcavation activities may result in archeological findings which could have a significant impact on the project schedule and overall construction costs. In our opinion, there is no benefit to thickening the slab-on-grade or adding additional reinforcement if seismic performance is not required for the project; the slab would still likely experience substantial settlement, cracking, and loss of functionality. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 29 If structural loading exceeds the typical range of allowable soil bearing pressures for RAP-supported foundations, or if predicted foundation settlements cannot be limited to structural design requirements, a deep foundation system will be required for this project. Deep foundation systems commonly used in the Puget Sound area include augercast piles, drilled shafts, micropiles, and driven steel pipe piles. We understand that the project structural engineer, PCS Structural Solutions (PCS), is planning to utilize augercast piles for the portion of the new school building that is adjacent to the 1930’s historical building, and that micropiles will be used for interior support of the 1930’s historical building. Our design recommendations for augercast piles and micropiles are provided further below in Sections 12.3 and 12.4. 12.1 Spread and Strip Footings on Rammed Aggregate Piers For footings founded directly upon properly completed RAPs, we recommend that an allowable bearing pressure of 4,000 psf be used for design purposes, including both dead and live loads. An increase in the allowable bearing pressure of one-third may be used for short-term wind or seismic loading. Perimeter footings should be buried at least 18 inches into the surrounding soil for frost protection. However, all foundations must bear directly on properly completed RAPs, and no foundations should be constructed in or above soft/loose, organic, or existing fill soils. Anticipated static settlement of footings founded on RAPs as recommended should be less than 1 inch with differential settlement one-half of the anticipated total settlement. Most of this movement should occur during initial dead load applications. However, disturbed material not removed from footing trenches prior to footing placement could result in increased settlements. Seismic performance and liquefaction-induced settlement tolerances of RAP-supported foundations and slabs-on-grade should be established by the structural engineer in coordination with AESI and the specialty design contractor. All footing areas should be inspected by AESI prior to placing concrete to verify that the RAPs are in the proper location, and construction conforms to the recommendations contained in this report. Foundation bearing verification will likely also be required by the municipality. Perimeter footing drains should be provided as discussed under the “Drainage Considerations” section of this report. It should be noted that the area bounded by lines extending downward at 1H:1V from any footing must not intersect another footing or intersect a filled area that has not been compacted to at least 95 percent of ASTM D-1557. If structural fill is placed below footing areas, the structural fill should extend horizontally beyond the footing by at least 1 foot. If new foundations are to be installed near existing buildings or structures, the footings should be the same depth to avoid surcharging or undercutting the existing foundations. In addition, a 1.5H:1V line extending down and away from any footing must not daylight because sloughing or raveling may eventually Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 30 undermine the footing. Thus, footings should not be placed near the edges of steps or cuts in the bearing soils. 12.2 Passive Resistance and Friction Factors Lateral loads can be resisted by friction between the foundation and the natural soils or supporting structural fill soils, and by passive earth pressure acting on the buried portions of the foundations. The foundations must be backfilled with structural fill and compacted to at least 95 percent of the maximum dry density to achieve the passive resistance design values recommended below. We recommend the following allowable design parameters which include a factor of safety of 1.5: Passive equivalent fluid = 250 pounds per cubic foot (pcf) Coefficient of friction = 0.30 The passive value presented above assumes an equivalent triangular fluid pressure distribution beginning at the surface. The triangular pressure distribution and resulting passive resistance should be truncated (ignored) to a depth of 2 feet from the ground surface. 12.3 Augercast Piles Based on information provided by PCS, we understand that augercast piles are planned to support the portion of the new school building that will be adjacent to the Performing Arts Center building. PCS is currently considering the use of 16-inch or 18-inch-diameter piles. We understand that the augercast piles will support axial loads of approximately 30 kips and lateral loads up to 30 kips, and that lateral deflection of the piles should be limited to ½ inch. Based on the borings completed near this area, we anticipate that the piles will penetrate loose/soft Black River alluvium to a depth on the order of 25 feet underlain by medium dense Cedar River alluvium extending beyond a depth of 50 feet. Groundwater is anticipated to be encountered at depths as shallow as 10 feet below existing grade, but could vary depending on the time of year and seasonal precipitation. Ultimate soil strength capacities were analyzed using the computer program AllPile Version 7.21h by CivilTech Software. A summary of recommended pile embedment depths and allowable capacities for 16-inch and 18-inch-diameter augercast piles are provided in Table 5 below. We recommend the augercast piles be extended to a minimum depth of 50 feet to penetrate the medium dense Cedar River alluvium and to resist potential downdrag loads imposed on the piles due to settlement of the liquefiable layers above. The anticipated post-construction settlement of the augercast pile-supported foundations will generally be on the order of ½ inch or less. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 31 Table 5 Augercast Pile Minimum Embedment and Capacities Pile Diameter (inches) Minimum Pile Embedment Depth Below Existing Grade(1) (feet) Allowable Axial Compressive Resistance(2) (kips) Lateral Capacity for 0.5-inch Deflection Under Free Head Conditions (kips) Lateral Capacity for 0.5-inch Deflection Under Fixed Head Conditions (kips) 16 55 30 12 25 18 50 30 14 30 (1) The minimum embedment depth corresponds to at least 10 feet below potentially liquefiable alluvial soils based on our exploration data. Actual pile embedment depths should be determined during construction in coordination with AESI. (2) The allowable axial compressive resistance corresponds to a safety factor of 2.5 for tip resistance and 2.0 for side friction resistance, and accounts for downdrag loads associated with the potential 40-foot zone of liquefiable soils above. Lateral Reduction Factors Augercast piles with lateral spacing less than six (6) pile diameters from another pile along the direction of force should be considered to be in the zone of influence, and the lateral capacity and the reduction factors presented below in Table 6 should be used. Table 6 Lateral Reduction Factors Pile Spacing in Direction of Loading Reduction Factor 6 diameters 1.0 5 diameters 0.8 4 diameters 0.6 3 diameters 0.4 Augercast Pile Construction Observations Construction planning should include allowing sufficient time for the grout to cure before drilling nearby piles. Typically, 24 hours of set time is recommended for piles closer than three (3) pile diameters or 10 feet, whichever is greater. The actual length of each augercast pile may be adjusted in the field based on the required capacity and conditions encountered during drilling. Since augercast piles are advanced in a closed hole with a continuous flight auger and withdrawn with a head of grout, the judgment and experience of the geotechnical engineer or their field representative must be used to assess if drilling conditions and pile advancement agree with the anticipated subsurface conditions, and to confirm the grout volumes exceed the theoretical volume of the borehole. Therefore, we recommend that all piles be observed by a qualified geotechnical engineer or engineering geologist from our firm, who can interpret and collect installation data and review the contractor’s operations. A final summary report would be issued after the pile installation is completed. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 32 12.4 Micropiles Based on information provided by PCS, we understand that micropiles will be installed within the interior of the 1930’s historical building. We understand that the micropiles will provide support of vertical loads only, and that no lateral capacity is needed. Micropiles are drilled and grouted reinforced piles that can have diameters ranging from 4 to 12 inches. They are used mainly as pressure-grouted friction piles to resist both tension and compression loads but can also provide resistance to lateral loads. Micropiles are installed with relatively small drilling equipment, allowing installation under limited-access and low-headroom conditions. Local contractors typically install a 7- or 8-inch-diameter micropile and have historically used the pin pile system approach. The pin pile system uses an outer pipe casing to stabilize the drill hole and an inner drill rod for cleaning out the casing or drilling farther into harder ground. After reinforcement is placed (typically a #18 or #20 all-thread steel bar), the casing is pulled under constant pressure grouting and left partly in the ground as additional reinforcement and to prevent grout loss into ground with large voids. The pin piles are then post-grouted as needed to achieve design capacity. Vertical Micropile Capacities Based on the medium dense Cedar River alluvium encountered below an average depth of 25 feet in the vicinity of the 1930’s building, and assuming the use of an 8-inch-diameter pile casing and secondary pressure grouting techniques, the micropile can be sized assuming an allowable soil/grout bond strength of 1,500 psf in both tension and compression below a depth of 40 feet (corresponding to an ultimate bond strength of at least 3,000 psf using a safety factor of 2). We recommend ignoring the soil/grout bond strength within the potential liquefiable zone to a depth of 40 feet. We estimate that foundations supported on micropiles may experience a maximum total settlement of ½ inch or less. The allowable bond strength is applicable to the “load zone” of the micropile embedded into the medium dense Cedar River alluvium below a depth of 40 feet. A minimum 40-foot-deep “no-load zone” should be established from the bottom of the new pile cap. We recommend that the sacrificial casing be left in place within the no-load zone to a depth of 40 feet to reduce the potential downdrag loads imposed on the load-zone portion of the pile after an earthquake event. We recommend a minimum spacing of 5 feet center-to-center for micropiles. Micropile Verification Load Testing As mentioned above, we anticipate an ultimate bond strength of at least 3,000 psf can be achieved for micropiles installed into the medium dense Cedar River alluvium below a depth of 40 feet. This strength value should be verified through verification load testing. At least two (2) Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 33 micropiles should be tested in tension to 2 times the allowable micropile load. The load-test anchor can be part of the permanent foundation system. The load test can use the surrounding ground for a reaction to the tension loading. The load test is to verify that the allowable soil/grout bond strength has been achieved and has a safety factor of at least 2. AESI should be present during the verification load testing and during the installation of all production micropiles on this project. 12.5 Auxiliary Structures We understand that small auxiliary structures such as restrooms, concessions, and athletic storage buildings are planned to be supported on a thickened slab-on-grade (mat slab). Since these structures are lightly loaded and have a relatively small footprint, any liquefaction-induced settlement that may occur during an extreme earthquake event is anticipated to be relatively uniform across the building footprint, and the zone of unsaturated fill and shallow alluvium (at least 5 feet thick) overlying the liquefiable soils will mitigate loss of bearing capacity. Therefore, it is our opinion that mat slabs are suitable for support of auxiliary structures. We recommend using a maximum allowable bearing pressure of 1,500 psf for mat slab design. Given the high potential for encountering very loose/soft subgrade soils at shallow depths, we recommend planning for 2 to 3 feet of overexcavation and replacement with structural fill below the entire slab footprint that extends 2 to 3 feet beyond the perimeter. The overexcavation depth would be determined at the time of construction in coordination with AESI. If very loose/soft soil conditions are still present at a depth of 3 feet below the bottom of slab, we recommend placing a stabilization/separation fabric overlain by an 8- to 12-inch layer of 2-inch ballast rock to “bridge” the overlying structural fill. It should be noted that mat-slab supported auxiliary structures may not be functional after an extreme earthquake event, depending on the magnitude of liquefaction-induced settlement that manifests at the ground surface. 12.6 Significant Pole Foundations We anticipate that drilled shafts will be utilized to support significant pole structures such as football goal posts, foul ball posts, tall field light posts, flag poles, scoreboard lighting, etc. No structural loading information was available at the time of this report; however, based on our experience with similar athletic field lights, we anticipate that the light poles will be supported on either 30-inch or 36-inch-diameter drilled shaft foundations cast “neat” against the sidewalls of drilled holes without the use of forms. The football goal post may be supported by a rectangular cast-in-place concrete footing that is backfilled with structural fill. The pole foundations are anticipated to be embedded into highly variable fill soils underlain by loose/soft Black River alluvium. Our exploration borings indicate that the existing fill soils onsite could be up to 7 feet thick and in a very loose condition. Historical explorations indicate that groundwater across the site could be as shallow as 5 feet below existing grade. Given the high potential for encountering variable soil types, very loose/soft soil conditions, and shallow Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 34 groundwater across the site, we recommend assuming conservative soil parameters for pole foundation design. Our recommended soil parameters for determining lateral and axial capacities of the pole foundations are provided below. Lateral Capacity Lateral loads on significant pole foundations caused by transient wind loading conditions may be resisted by passive soil pressure against the side of the foundation. We recommend using a conservative allowable passive earth pressure of 200 pcf, expressed as an equivalent fluid unit weight, to a depth of 5 feet below grade. Below a depth of 5 feet, we recommend using a “submerged” passive earth pressure of 100 pcf to account for potential shallow groundwater conditions. These allowable values include a safety factor of 1.5. The above values only apply to foundation elements cast “neat” against undisturbed soil. The passive values presented should be applied as a triangular pressure distribution over twice the diameter of the foundation. The passive earth pressure should be neglected (truncated) to a depth of 2 feet below the ground surface and held at a constant value at a depth greater than 8 feet. Axial Capacity For this project, we assume that the lateral loads will be the most critical design factor for the light pole foundations and will control the depth of embedment; however, for design purposes, we recommend using an allowable end-bearing pressure of 1,500 psf for resisting axial loads. Additional vertical capacity can also be achieved through friction along the shafts, as described below. Frictional Resistance For frictional resistance along the drilled shaft, we recommend using a conservative allowable skin friction value of 200 psf for the full shaft length, excluding the uppermost 2 feet below the ground surface. Drilled Shaft Construction Recommendations The excavation equipment must be capable of maintaining a stable borehole with no caving while drilling into potentially very loose/soft soil conditions accompanied by a shallow water table. Depending on location-specific soil and groundwater conditions at the time of drilling, temporary casing may be required to prevent caving, and a sump pump may be needed to remove accumulated water from the base of the hole prior to placing concrete. The contractor should have the ability to excavate and remove debris or other obstacles that may be encountered within the existing fill during drilled shaft excavation. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 35 Alternative Analysis Options The soil parameters presented above are conservative to account for highly variable soil and groundwater conditions across a large area. AESI is available to analyze location-specific pole foundations upon request. It is possible that higher lateral capacities and/or shallower embedment depths could be achieved by completing a lateral load analysis using structural loading information provided by the design engineer and accounting for the bending moment resistance of the drilled shaft. 12.7 Site Signs and Sidewalk Light Posts Depending on the size and height of site signs and sidewalk light posts, wind loading could result in significant lateral forces. We recommend using the soil parameters provided in the “Significant Pole Foundations” section above in this case to determine the required diameter and embedment depth of the post foundation. AESI is available to review location-specific designs upon request. 12.8 Site Fences and Gates We recommend that fences and gates be installed in postholes that are at least 4 feet deep below the ground surface. For fences and gates that are not subject to significant wind loading, we recommend a posthole diameter of at least 3 times the width of the foundation post, or a minimum diameter of 12 inches, whichever is larger. We recommend placing at least 6 inches of concrete between the base of the hole and bottom of post. After the posts are set and adjusted for plumbness, the annulus should be filled with concrete. If significant wind loading is anticipated on a particular fence or gate due to its height or the installation of windscreens or netting, we recommend that AESI review the loading conditions and foundation post detail to confirm or adjust the posthole diameter and/or embedment depth. 13.0 FLOOR SUPPORT Where ground improvement is utilized for building support, we recommend that slab-on-grade floors be constructed over an array of vibratory stone columns or RAPs to mitigate post-liquefaction differential settlement. Where deep foundations are utilized for building support, we recommend that the lower-level floors be designed as structural floors using pile-supported grade beams. In order to control moisture vapor transfer through the slab, the slabs-on-grade should be cast atop a minimum of 4 inches of washed pea gravel or clean, washed crushed rock to act as a capillary break. It should also be protected from dampness by an impervious, 15-mil (minimum Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 36 thickness) plastic sheeting placed atop the capillary break specifically designed for use as a moisture barrier. 14.0 CAST-IN-PLACE RETAINING WALLS AND BELOW-GRADE WALLS We anticipate that most of the structures will be at or near existing grades with minimal site grading involved to establish final grades across the site. Our design and construction recommendations for cast-in-place retaining walls under 4 feet in height are presented below. If the project should require retaining walls greater than 4 feet in height, we are available to provide additional design parameters upon request. All backfill placed behind site walls and foundation walls should be placed in accordance with the recommendations contained in the “Structural Fill” section of this report. Horizontally backfilled walls, which are free to yield laterally at least 0.1 percent of their height, may be designed to resist lateral earth pressure represented by an equivalent fluid pressure equal to 35 pcf. Fully restrained, horizontally backfilled, rigid walls that cannot yield should be designed for an equivalent fluid pressure of 55 pcf. Walls with sloping backfill up to a maximum gradient of 2H:1V should be designed using an equivalent fluid pressure of 55 pcf for yielding conditions or 75 pcf for fully restrained conditions. If vehicle parking areas are adjacent to walls, we recommend a vertical surcharge equal to 250 psf be added to the wall height in determining the lateral design forces. In hardscape areas with pedestrian traffic, we recommend a live load vertical surcharge equal to 100 psf. The lateral pressure resulting from each vertical surcharge can be calculated by multiplying the surcharge load by 0.4 and applying the load as a rectangular distribution along the height of the wall. A qualified structural engineer should check the stability of site retaining walls with respect to sliding and overturning using the lateral earth pressures presented above. 15.0 DRAINAGE CONSIDERATIONS Traffic across the on-site soils when they are damp or wet will result in disturbance of the otherwise firm stratum. Therefore, during site work and construction, the contractor should provide surface drainage and subgrade protection, as necessary. Groundwater was encountered at depths between 9.5 and 14 feet at the time of our exploration and is likely shallower in the winter or following large storm events. Previous explorations at the site have indicated groundwater levels as shallow as 4.5 feet at the time of drilling in early March. Zones of perched groundwater may also be present within the fill at the contact with the finer-grained Black River alluvium, particularly after large storm events or near existing utility Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 37 backfill. Therefore, we recommend that contractors be prepared to encounter groundwater seepage within deeper excavations for utilities or other project elements. Where relatively shallow excavations on the order of 5 feet or less are required and take place in the drier months of the year, surface and groundwater seepage could be managed during construction with conventional ditches and sumps. Where deeper excavations greater than 5 feet are required and take place during the wet season, more complex dewatering systems may be required to maintain dry working conditions. All perimeter footings, slabs, and retaining walls should be provided with a drain at the footing or subgrade elevation. Drains should consist of rigid, perforated, PVC pipe surrounded by washed gravel. The level of the perforations in the pipe should be set at the bottom of the footing, and the perforations should be located on the lower portion of the pipe. The drains should be constructed with sufficient gradient to allow gravity discharge away from the structures. In addition, any retaining or subgrade walls should be lined with a minimum, 12-inch-thick, washed gravel blanket. Roof and surface runoff should not discharge into the footing drain system, but should be handled by a separate, rigid, tightline drain. In planning, exterior grades adjacent to walls should be sloped downward away from the structures at an inclination of at least 3 percent to achieve surface drainage. Runoff water from impervious surfaces should be collected by a storm drain system that discharges into the site stormwater system. 16.0 PAVEMENT RECOMMENDATIONS The pavement sections included in this report section are for driveway and parking areas onsite and are not applicable to right-of-way improvements. We are available to offer situation-specific recommendations for planned right-of-way improvements once project plans are more developed. Pavement areas should be prepared in accordance with the “Site Preparation” section of this report. If the existing fill subgrade can be compacted to 95 percent of ASTM D-1557 and is firm and unyielding during proof-rolling, no additional overexcavation is required. Soft or yielding areas should be overexcavated to provide a suitable subgrade and backfilled with structural fill. The upper 2 feet of pavement subgrade should be recompacted to 95 percent of ASTM D-1557. If required, structural fill may then be placed to achieve desired subbase grades. The near-surface existing fill soils across the site generally consisted of very loose to loose silty sand with scattered organics and appear to be marginal for pavement subgrade support in its current condition. We anticipate that subgrade preparation for new pavements will require remedial efforts, such as recompaction and overexcavation/replacement, and that these remedial efforts may be more extensive than typically needed for sites containing pavement Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 38 subgrades that are comprised of medium dense granular fill or native granular sediments. Therefore, our recommended pavement sections below include an overall thicker base course layer to account for the potentially marginal subgrades across the site. We anticipate the project will include light-duty pavements for passenger vehicles and heavy-duty pavements for buses, fire trucks, and garbage trucks. Our recommendations for asphalt pavement sections and concrete pavement sections are provided below. 16.1 Asphalt Pavement Sections In light-duty traffic areas, we recommend a pavement section consisting of 3 inches of hot-mix asphalt (HMA) underlain by 12 inches of ¼-inch crushed surfacing base course (Washington State Department of Transportation [WSDOT] 9-03.9(3) “CSBC” or approved equivalent) as the recommended minimum in areas of planned passenger car lanes and parking. In heavy-duty traffic areas, a minimum pavement section consisting of 4 inches of HMA underlain by 18 inches of CSBC is recommended. The CSBC must be compacted to 95 percent of the maximum density, as determined by ASTM D-1557. All paving materials should meet gradation criteria contained in the current WSDOT Standard Specifications. It should be noted that the performance of a pavement section is highly dependent on the subgrade conditions during construction. If pavement construction is planned for the dry summer months and the exposed subgrades are generally comprised of silty sand (as indicated by our exploration borings), are suitably compacted in place, and perform well during proof-rolling, the CSBC thickness could potentially be reduced to 6 inches for light-duty areas and 12 inches for heavy-duty areas. Where subgrade areas expose very silty subgrades that have lower support strength and/or construction takes place in wet weather conditions, the subgrade may require overexcavation/replacement with new structural fill or the placement of a stabilization fabric. Therefore, it is imperative that AESI be present during pavement subgrade preparation to assess if a reduced CSBC section can be achieved. Depending on construction staging and desired performance, a portion of the crushed rock base course layer may be substituted with ATB beneath the final asphalt surfacing. The substitution of ATB should be as follows: 4 inches of crushed rock can be substituted with 3 inches of ATB, and 6 inches of crushed rock may be substituted with 4 inches of ATB. ATB should be placed over a firm and unyielding subgrade as determined by proof-rolling and a 1½- to 2-inch thickness of crushed rock to act as a working surface. If ATB is used for construction access and staging areas, some rutting and disturbance of the ATB surface should be expected. The general contractor should remove affected areas and replace them with properly compacted ATB prior to final surfacing. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 39 16.2 Concrete Pavement Sections The following recommended sections for concrete pavements are preliminary and intended for planning purposes only. We are available to provide situation-specific designs if concrete pavements are included in the final design plans. In light-duty traffic areas, we anticipate a minimum pavement section consisting of 4 inches of concrete underlain by 6 inches of compacted CSBC. In heavy-duty traffic areas, we anticipate a minimum pavement section of 6 inches of concrete underlain by 12 inches of compacted CSBC. 17.0 INFILTRATION FEASIBILITY Stormwater infiltration feasibility depends upon the presence of a suitable native receptor soil of sufficient thickness, extent, permeability, and vertical separation from the groundwater table. Overall, infiltration appears very limited at the site based on our recent explorations, as further discussed below. Shallow-depth infiltration opportunities at the site are limited by the presence and thickness of surficial fills, low-permeability silt layers observed within the finer-grained Black River alluvial sediments directly underlying the fill, and relatively shallow groundwater conditions. Where higher-permeability Cedar River alluvial sediments are present directly below the existing fill, as encountered in EB-6W, the limiting factor for infiltration feasibility will be the separation between the base of the proposed infiltration facility and the seasonal high water table. At the time of drilling, groundwater was encountered at depths ranging from about 10 to 14 feet below the existing ground surface. AESI has monitored seasonal groundwater levels within the on-site wells (EB-1W, EB-3W, and EB-6W) starting from well development in April 2024 through June 25, 2025. A hydrograph illustrating approximate groundwater elevations and precipitation amounts over time is presented in Appendix D. During this monitoring period, groundwater elevations have ranged from about 20 to 22 feet in August/September 2024 (seasonal low) to about 23.5 to 26 feet in late March/early April 2025 (seasonal high). It should be noted that historical explorations at the site have indicated groundwater levels as shallow as 4.5 feet at the time of drilling in early March (see Table 2 in the “Hydrology” section of this report). 17.1 Infiltration Feasibility – Main School Campus We understand that no infiltration facilities are planned at this time. As discussed in the “Critical Aquifer Recharge Areas” section of this report, the approximate eastern half of the school campus and proposed improvements are located within a Zone 1 WHPA and the approximate western half of the school campus and proposed improvements are located within a Zone 2 WHPA. Per the City’s comprehensive water system plan, no infiltration is allowed within Zone 1 Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 40 WHPAs. Therefore, only the western track and field and parking lot area located within the Zone 2 WHPA could potentially utilize infiltration for this project; however, our exploration data in this area indicates that the western portion of the campus is primarily underlain by a surficial layer of existing fill overlying silty alluvial sediments accompanied by a shallow water table (approximately 7 to 10 feet below existing grade at the time of exploration). Therefore, infiltration opportunities in the Zone 2 area appear to be limited to shallow low-capacity infiltration BMPS such as permeable pavements or permeable roof drain leaders for small outbuildings. 17.2 Infiltration Feasibility – Northern Campus Expansion within Residential Block The campus expansion will include new athletic fields to the north within the existing 7-acre residential block that is bounded by South Tobin Street to the south, Shattuck Avenue South to the west, Airport Way to the north, and Logan Avenue South to the east. The eastern two-thirds of the residential block is located within a Zone 1 WHPA (no infiltration) while the western one-third is located within a Zone 2 WHPA. Based on our recent site observations made in July 2025 during house demolition and backfilling of basement structures in this area (Lots 1, 2, and 3), the subsurface soil conditions within the northern residential block appear similar to the subsurface conditions encountered within our borings across the main school campus. The near-surface soils observed during basement demolition generally consisted of silty sand. Additionally, the geothermal test loop borings GTL-1 and GTL-3 were located on the vacant parcel within the residential block and encountered fill soils (silty sand and sandy silt) to a depth of about 5 feet, underlain by Holocene alluvium that generally consisted of silty sand. Given the relatively flat topography across the site, we anticipate that groundwater levels below the residential block would be similar to groundwater levels encountered in EB-1W. Therefore, it appears that infiltration opportunities in the Zone 2 area would be limited to shallow low-capacity infiltration BMPs such as permeable pavements or permeable roof drain leaders for small outbuildings. 18.0 PROJECT DESIGN AND CONSTRUCTION MONITORING We recommend that AESI be allowed to review this report and update it as needed once the campus replacement plans are finalized. In this way, we can confirm that our earthwork and foundation recommendations have been properly interpreted and implemented in the design. We also recommend that AESI perform a geotechnical plan review of all earthwork- and foundation-related specifications prior to completion of the final design. We are available to provide geotechnical observation and testing services during construction. The integrity of the earthwork and foundations depends on proper site preparation and construction procedures. In addition, engineering decisions may have to be made in the field in the event that variations in subsurface conditions become apparent. Subsurface Exploration, Geologic Hazard, Renton High School Replacement and Geotechnical Engineering Report Renton, Washington Design Recommendations September 3, 2025 ASSOCIATED EARTH SCIENCES, INC. BCY/ld – 20210249E002-007 Page 41 We have enjoyed working with you on this study and are confident these recommendations will aid in the successful completion of your project. If you should have any questions or require further assistance, please do not hesitate to call. Sincerely, ASSOCIATED EARTH SCIENCES, INC. Kirkland, Washington ______________________________ Brendan C. Young, L.G. Senior Staff Geologist ______________________________ Matthew A. Miller, P.E. G. Bradford Drew, P.E. Principal Engineer Associate Engineer Attachments: Figure 1: Vicinity Map Figure 2: Existing Site and Exploration Plan Figure 3: Proposed Site and Exploration Plan Appendix A: Boring Logs Appendix B: CPT Logs Appendix C: Historical Exploration Logs (AESI, 1999, 2009, 2024) Appendix D: Hydrograph Appendix E: Laboratory Test Results Appendix F: Liquefaction Analysis Results Appendix G: Shear Wave Velocity Survey (WGS, 2020) Appendix H: Wellhead Protection Zone Map G:\ G I S _ P r o j e c t s \ a a Y 2 0 2 1 \ 2 1 0 2 4 9 R e n t o n H S \ _ a p r x \ 2 0 2 1 0 2 4 9 E 0 0 2 F 1 VM _ R e n t o n H S . a p r x | 2 0 2 1 0 2 4 9 E 0 0 2 F 1 V M _ R e n t o n H S | 2 0 2 4 - 0 4 - 0 4 | k b e h m COUNTY LOCALE LOCATION PROJECT NO.DATE FIGURE 13/2520210249E002 RENTON HIGH SCHOOLRENTON, WASHINGTON VICINITY MAP ESRI, USGS, NATIONAL GEOGRAPHIC,DELORME, NATURALVUE, I-CUBED, GEBCO:ARCGIS ONLINE BASEMAP. WADOT STATEROUTES 24K (12/20). KING CO: PARCELS(4/23), ROADS (5/23). NOTE: LOCATION AND DISTANCES SHOWNARE APPROXIMATE. BLACK AND WHITEREPRODUCTION OF THIS COLOR ORIGINALMAY REDUCE ITS EFFECTIVENESS AND LEADTO INCORRECT INTERPRETATION. King County S TOBIN ST SR 900 LO G A N A VE S 405 515 900 167 169 Lake Washington KING COUNTY KI N G CO U N T Y RENTON SE A T T L E 0 2,000 FEET m SITE BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAYREDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION.LOCATION AND DISTANCES SHOWN ARE APPROXIMATE. G:\ G I S _ P r o j e c t s \ a a Y 2 0 2 1 \ 2 1 0 2 4 9 R e n t o n H S \ _ a p r x \ E 0 0 2 _ 2 5 0 3 \ 2 0 2 1 0 2 49 E 0 0 2 F 2 E S _ R e n t o n H S _ 2 5 0 3 . a p r x | 2 0 2 1 0 2 4 9 E 0 0 2 F 2 E S _ R H S _ 2 5 0 3 | 2 0 2 5 - 0 4 - 2 1 | m t r o p PROJECT NO.DATE FIGURE ± 24/2520210249E002 RENTON HIGH SCHOOLRENTON, WASHINGTON EXISTING SITE AND EXPLORATIONS DATA SOURCES / REFERENCES:WADNR WGS: WA LIDAR PORTAL, KING CO. 2021, USGS 3DEPGRID CELL SIZE 1.5', FLOWN 4/2021CONTOURS DERIVED FROM LIDARKING CO: STREETS, PARCELS, 4/23AERIAL PICTOMETRY INT. 2021 0 150 FEET ^ dŽďŝŶ ^ƚ ^w ϵϬϬ > Ă Ŭ Ğ ǀ Ğ ^ > Ž Ő Ă Ŷ ǀ Ğ ^ ^w ϵϬϬ ŝƌƉŽƌƚ tĂLJ ^dŝůůŝĐƵŵ ^ƚ (3 (3 (3 (3 (% (% (% (% (% (% (% (% (% (% (% (% (% (% (% (% (% (% (%: (%(%: (% (% (%: &37 &37 &37 (3 (3 *7/ (% (% (% (% (% (% *7/ *7/ 3 34 3 30 3 3 34 32 2 3 34 32 2 4 4 32 30 32 2 3 3 3 3 3 34 34 34 32 32 34 34 3 4 32 32 RentonHighSchool ERI EW LLQH SITE EXPLORATION TYPE - YEAR EXPLORATION BORING MONITORING WELL EXPLORATION PIT CONE PENETROMETER GEOTHERMAL TEST LOOP SEISMIC ARRAY (WADNR WGS OFR 2019-01) ERI E-W LINE PARCEL CONTOUR 10 FT CONTOUR 2 FT BLACK AND WHITE REPRODUCTION OF THIS COLOR ORIGINAL MAYREDUCE ITS EFFECTIVENESS AND LEAD TO INCORRECT INTERPRETATION.LOCATION AND DISTANCES SHOWN ARE APPROXIMATE. G:\ G I S _ P r o j e c t s \ a a Y 2 0 2 1 \ 2 1 0 2 4 9 R e n t o n H S \ _ a p r x \ E 0 0 2 _ 2 5 0 3 \ 2 0 2 1 0 2 49 E 0 0 2 F 3 S P _ R e n t o n H S _ 2 5 0 3 . a p r x | 2 0 2 1 0 2 4 9 E 0 0 2 F 3 S P _ R H S _ 2 5 0 3 | 2 0 2 5 - 0 8 - 1 1 | m t r o p PROJECT NO.DATE FIGURE ± 38/2520210249E002 RENTON HIGH SCHOOLRENTON, WASHINGTON PROPOSED SITE PLAN AND EXPLORATIONS DATA SOURCES / REFERENCES:AHBL, RENTON HIGH SCHOOL REPLACEMENT, PROJECT PLAN,SHEET C1.0, 6/6/25 0 150 FEET EP-1-99 EP-2-99 EP-3-99 EP-4-99 EB-1-99 EB-2-99 EB-3-99 EB-4-99 EB-1-09EB-2-09EB-3-09 EB-4-09 EB-5-09 EB-6-09 EB-7-09EB-8-09 EB-9-09 EB-10-09 EB-11-09 EB-12-09 EB-13-09 EB-14-09 EB-1W-24 EB-2-24 EB-3W-24 EB-4-24 EB-5-24 EB-6W-24 CPT-01-24 CPT-02-24 CPT-03-24 EP-1-24 EP-2-24 GTL-1-24 EB-1-03 EB-2-03EB-3-03 EB-4-03 EB-5-03EB-6-03 GTL-2-25 GTL-3-25 (5,(:/LQH SITE EXPLORATION TYPE - YEAR EXPLORATION BORING MONITORING WELL EXPLORATION PIT CONE PENETROMETER GEOTHERMAL TEST LOOP SEISMIC ARRAY (WADNR WGS OFR 2019-01) ERI E-W LINE APPENDIX A Boring Logs Classifications of soils in this report are based on visual field and/or laboratory observations,which include density/consistency, moisture condition, grain size, and plasticity estimatesand should not be construed to imply field or laboratory testing unless presented herein.Visual-manual and/or laboratory classification methods of ASTM D-2487 and D-2488 wereused as an identification guide for the Unified Soil Classification System. OH PT CH OL MH CL ML SM SC GW SP GC SW GM GP Well-graded gravel and gravel with sand, little to no fines Poorly-graded gravel and gravel with sand, little to no fines Clayey gravel and clayey gravel with sand Silty gravel and silty gravel with sand Well-graded sand and sand with gravel, little to no fines Poorly-graded sand and sand with gravel, little to no fines Clayey sand and clayey sand with gravel Organic clay or silt of low plasticity Organic clay or silt of medium to high plasticity Peat, muck and other highly organic soils Silty sand and silty sand with gravel Silt, sandy silt, gravelly silt, silt with sand or gravel Clay of low to medium plasticity; silty, sandy, or gravelly clay, lean clay Elastic silt, clayey silt, silt with micaceous or diatomaceous fine sand or silt Clay of high plasticity, sandy or gravelly clay, fat clay with sand or gravel (1 ) Hi g h l y Or g a n i c So i l s Fin e - G r a i n e d S o i l s - 5 0 % o r M o r e P a s s e s N o . 2 0 0 S i e v e (1 ) Co a r s e - G r a i n e d S o i l s - M o r e t h a n 5 0 % R e t a i n e d o n N o . 2 0 0 S i e v e Gr a v e l s - M o r e t h a n 5 0 % o f C o a r s e F r a c t i o n Re t a i n e d o n N o . 4 S i e v e 12 % F i n e s 5% F i n e s Sa n d s - 5 0 % o r M o r e o f C o a r s e F r a c t i o n Pa s s e s N o . 4 S i e v e Si l t s a n d C l a y s Li q u i d L i m i t L e s s t h a n 5 0 Sil t s a n d C l a y s Li q u i d L i m i t 5 0 o r M o r e (1 ) (1 ) 12 % F i n e s 5% F i n e s (2 ) (2 ) (2 ) (2 ) Terms Describing RelativeDensity and Consistency Estimated Percentage Moisture Content Percentage by Weight <5 5 to <12 12 to <30 30 to <50 Component Definitions Component Trace Some Modifier (silty, sandy, gravelly) Very modifier (silty, sandy, gravelly) Size Range and Sieve Number Larger than 12" Descriptive Term Smaller than No. 200 (0.075 mm) 3" to 12" Coarse- Grained Soils Fine- Grained Soils Density Very Loose Loose Medium DenseDense Very Dense SPT blows/foot 0 to 4 4 to 10 10 to 3030 to 50 >50 (3) 0 to 2 2 to 4 4 to 8 8 to 15 15 to 30>30 Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard SPT blows/foot(3) Test Symbols No. 4 (4.75 mm) to No. 200 (0.075 mm) Boulders Silt and Clay Gravel Coarse Gravel Fine Gravel Cobbles Sand Coarse Sand Medium Sand Fine Sand Dry - Absence of moisture, dusty, dry to the touch Slightly Moist - Perceptiblemoisture Moist - Damp but no visible water Very Moist - Water visible butnot free draining Wet - Visible free water, usually from below water table G = Grain Size M = Moisture Content A = Atterberg Limits C = Chemical DD = Dry Density K = Permeability No. 4 (4.75 mm) to No. 10 (2.00 mm) No. 10 (2.00 mm) to No. 40 (0.425 mm) No. 40 (0.425 mm) to No. 200 (0.075 mm) 3" to No. 4 (4.75 mm) 3" to 3/4" 3/4" to No. 4 (4.75 mm) Symbols Sampler Type and Description Blows/6" or portion of 6"15 10 20 California Sampler Ring Sampler Continuous Sampling Grab Sample Portion not recovered Split-Spoon Sampler (SPT) Cement grout surface seal Bentonite seal Filter pack with blank casing section Screened casing or Hydrotip with filter pack End cap ATD At time of drilling Static water level (date) (1)Percentage by dry weight(2)Combined USCS symbols used for fines between 5% and 12%(3)(SPT) Standard Penetration Test (ASTM D-1586)(4)In General Accordance with Standard Practice for Descriptionand Identification of Soils (ASTM D-2488) Groundwaterdepth i n c o r p o r a t e d e a r t h s c i e n c e s a s s o c i a t e d EXPLORATION LOG KEY FIGURE:A1Blo c k s \ d w g \ l o g _ k e y 2 0 2 2 . d w g L A Y O U T : L a y o u t 5 - 2 0 2 2 L o g d r a f t 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Asphalt - 3 inches / No Base Course FillMoist, dark brown to black transitioning to brown, gravelly, SAND, some silt becoming silty, fine SAND, some gravel with depth; rare organics (rootlets (SP- SM).Moist, brown with oxidation staining to orange, fine SAND, trace silt (SP). Black River AlluviumVery moist, gray with orange oxidation staining, finesandy, SILT, trace to some gravel (ML).Very moist, gray, sandy, SILT, trace gravel; scatteredorganics (fine organics and rootlets); occasionalinterbed of fine sand; organic odor (ML).Very moist, gray, SILT; occasional brown silt, somefine sand; interbeds of fine to medium sand, some silt(ML).Wet, gray, silty, fine to medium SAND; occasional interbed of fine sandy, silt, trace organics (SM).Driller adding water and drilling fluid. Wet, gray, fine sandy, SILT; occasional interbeds of fine sand; rare fine organics (ML). As above; occasional interbeds of fine to medium sand (ML). Cedar River AlluviumDriller notes increase in gravel. Wet, brown, fine to coarse SAND (coarsening withdepth); trace silt; some gravel at tip of spoon (SP). Wet, brownish gray, fine to medium SAND; becomingmedium to coarse sand, some gravel; rare interbed ofgray, silt (SP). Wet, brownish gray, fine to medium SAND, some gravel; massive (SP-SM). 142614 111 111 111 222 111 224 244 677 67 40 2 2 2 4 2 6 8 14 15 Flush mount monumentConcrete 0 to 2 feet Bentonite chips 2 to 8 feet 2-inch I.D. sch. 40 PVCcasing 0 to 10 feet Sand 8 to 22 feet 2-inch I.D. PVC well screen 0.010-inch slot width 10 to 20 feet End cap; threaded connection Slough 22 to 51.5 feet Associated Earth Sciences, Inc. Monitoring Well EB-1W Renton High School ReplacementRenton, Washington Start Date: 4/9/2024 Logged By: BCY20210249E002Ending Date: 4/9/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):20Hole Diameter (in):6 Well Tag No.:BPQ286Ground Surface Elevation (ft):»32 Top of Well Casing Elevation (ft):»31.7Water Level Elevation (ft):20.2 Datum:NAVD 88Groundwater Depth ATD (ft): 11.8 Groundwater Depth Post Drilling (ft) (Date): 9.5 ( 4/29/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 11 12 13 Driller notes layers of sand and layers of gravel; changing drill action. As above; gravel in bottom 3 inches of spoon; interbeds of brown, silty, fine sand (SP). As above; sandy (6 inches thick) at tip of spoon; broken gravel; blow counts may be overstated. Wet, brownish gray, fine to medium SAND, trace gravel; oxidation staining around gravel; blow counts may be overstated (SP). Groundwater encountered at 11.8 feet ATD. Groundwater encountered at 9.5 feet on 4/29/24. 8 131116 101527 141625 27 42 41 Associated Earth Sciences, Inc. Monitoring Well EB-1W Renton High School ReplacementRenton, Washington Start Date: 4/9/2024 Logged By: BCY20210249E002Ending Date: 4/9/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):20Hole Diameter (in):6 Well Tag No.:BPQ286Ground Surface Elevation (ft):»32 Top of Well Casing Elevation (ft):»31.7Water Level Elevation (ft):20.2 Datum:NAVD 88Groundwater Depth ATD (ft): 11.8 Groundwater Depth Post Drilling (ft) (Date): 9.5 ( 4/29/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Sod / Topsoil - 3 inches FillMoist, dark brown, silty, fine to medium SAND, some gravel; abundant organics (fine black organics and rootlets) (SM).Slightly moist, brown with some dark brown and orangish brown, silty, fine to medium SAND, some gravel; scattered organics (charcoal and rootlets) (SM). Black River AlluviumSlightly moist, brownish gray with some orange oxidation staining, fine SAND, some silt (SP-SM). Moist to very moist, gray to dark brown, SILT to organic SILT; abundant fine organics with strong odor; massive (ML/OL). As above; occasional interbeds (approximately 1 inch thick) of fine sand; fewer organics (ML). As above; becomes wet with rare wood debris. Cedar River Alluvium Driller notes gravel. Driller adding water. Wet, gray, fine SAND; becomes medium to coarse sand with depth, trace silt; transitioning to gravel, some coarse sand, trace silt at bottom of sample (SP- GP). Wet, brown and gray, sandy, GRAVEL, trace silt; broken gravel; stratified; blow counts overstated (GW). Wet, grayish brown, silty, GRAVEL, some sand; occasional interbed of gray, silty, fine sand (GM). Wet, gray, silty, fine SAND, some gravel (SM). 598 143 322 232 212 213 141415 121520 743 9913 17 7 4 5 3 4 29 35 7 22 Associated Earth Sciences, Inc. Exploration Boring EB-2 Renton High School ReplacementRenton, Washington Start Date: 4/10/2024 Logged By: BCY20210249E002Ending Date: 4/10/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):13.3 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 75 11 12 13 Wet, brown, fine to medium SAND, some gravel, some silt; interbedded with gray, silty, fine SAND, trace organics (SP-SM). Wet, brown, sandy, GRAVEL, some silt; broken gravel in sampler; blow counts may be overstated (GW-GM). Wet, brown, silty, GRAVEL, some fine to medium sand (GM). Groundwater encountered at 13.3 feet ATD. Practical auger refusal due to large gravels. 121516 222528 261816 31 53 34 Associated Earth Sciences, Inc. Exploration Boring EB-2 Renton High School ReplacementRenton, Washington Start Date: 4/10/2024 Logged By: BCY20210249E002Ending Date: 4/10/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):13.3 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Sod / Topsoil - 3 inches FillSlightly moist, brown, silty, fine SAND; scattered to abundant organics (charcoal and rootlets); silt content decreases with depth (SM).Slightly moist, brown, silty, SAND, some gravel; scattered to abundant organics (charcoal/rootlets) (SM). Black River AlluviumVery moist, brown and gray with orange oxidationstaining, SILT, some fine sand; occasional interbed offine sand, some fine organics (ML).Moist, brown to orange, very silty, fine SAND, tracegravel; occasional interbed of brownish gray, silt;pockets of heavily organic, dark brown, silty, sand(SM).Wet, brown to reddish brown, fine SAND, and silty,fine SAND; becomes gravelly, sand, some silt (at 11feet); faintly stratified (SM). Wet, brown becoming gray, fine SAND, some silt; large piece (3 inches) of wood debris at top of spoon (SP-SM). Wet, gray, silty, fine SAND; interbeds (<2.5 inches thick) of gray, fine sand; some gravel (SM). Wood debris present at 21 feet. Wet, gray, silty, fine SAND, trace gravel; wooddebris, rare rootlets; broken gravel at tip of spoon;abundant fine organics; blow counts may beoverstated (SM).Cedar River Alluvium Wet, brown, sandy, GRAVEL, trace silt; blow countsmay be overstated (GW). Wet, brown, GRAVEL, some medium sand, trace silt (GW). 224 322 111 543 2610 213 81016 6815 81321 148 6 4 2 7 16 4 26 23 34 17 Flush mount monumentConcrete 0 to 2 feet Bentonite chips 2 to 10 feet 2-inch I.D. sch. 40 PVCcasing 0 to 13.4 feet Sand 10 to 26 feet 2-inch I.D. sch. 40 PVC well screen 0.010-inch slot width 13.4 to 23.4 feet Endcap Slough 26 to 51.5 feet Associated Earth Sciences, Inc. Monitoring Well EB-3W Renton High School ReplacementRenton, Washington Start Date: 4/10/2024 Logged By: BCY20210249E002Ending Date: 4/10/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):23.4Hole Diameter (in):6 Well Tag No.:BPQ287Ground Surface Elevation (ft):»34 Top of Well Casing Elevation (ft):»33.6Water Level Elevation (ft):20.4 Datum:NAVD 88Groundwater Depth ATD (ft): 13.6 Groundwater Depth Post Drilling (ft) (Date): 12.1 ( 4/29/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 11 12 13 Wet, brown, very sandy, GRAVEL, trace silt; blow counts may be overstated (GW). Wet, brown to brownish gray, fine SAND, trace silt; layered with GRAVEL, some fine to medium sand, trace silt; broken gravel in split spoon (SP). Wet, brownish gray with occasional deep red oxidation staining, fine to medium SAND, some gravel, trace to some silt; blow counts may be overstated (SP-SM). Groundwater encountered at 13.6 feet ATD. Groundwater encountered at 12.1 feet on 4/29/ 24. Practical auger refusal due to large gravel. 9 262318 8911 341826 41 20 44 Associated Earth Sciences, Inc. Monitoring Well EB-3W Renton High School ReplacementRenton, Washington Start Date: 4/10/2024 Logged By: BCY20210249E002Ending Date: 4/10/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):23.4Hole Diameter (in):6 Well Tag No.:BPQ287Ground Surface Elevation (ft):»34 Top of Well Casing Elevation (ft):»33.6Water Level Elevation (ft):20.4 Datum:NAVD 88Groundwater Depth ATD (ft): 13.6 Groundwater Depth Post Drilling (ft) (Date): 12.1 ( 4/29/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Sod / Topsoil - 3 inches FillSlightly moist to moist, brown to dark brown, very gravelly, silty, SAND; scattered organic rootlets); bottom 3 inches becomes brown, fine to medium SAND, some gravel, trace silt (SM).Slightly moist, dark brown transitioning to brown mixed with tan with occasional faint orange oxidation staining, silty, fine to medium SAND, some gravel; scattered organics (rootlets); disturbed texture (SM). Black River AlluviumMoist grayish brown with abundant oxidation staining to orange, sandy, SILT ranging to very silty, fine SAND, rare gravel; scattered organics (fine black organics and rootlets); organics appear in some horizontal interbeds (ML/SM).Moist, grayish brown, sandy, SILT ranging to SILT; occasional layer (<1 inch thick) of heavily oxidized, sand; scattered organics (charcoal and rootlets) (ML).Moist, gray to brown with heavy oxidation staining to orange, sandy, SILT, some gravel; occasional interbed (<1 inch thick) of fine sand (ML). Wet, gray and brown, fine SAND, some silt; occasional interbed of silty, fine to medium sand, fine gravel at tip of spoon (SP-SM). Driller notes increasing gravel content. Wet, gray, fine to coarse SAND, some gravel, trace silt; sample coarsens with depth; gravel in tip of sampler; blow counts may be overstated (SP). Cedar River Alluvium Wet, brown, sandy, GRAVEL, trace silt; gravel filled diameter of sampler; blow counts may be overstated (GW). Wet, brown with heavy oxidation staining, very sandy, GRAVEL, some silt; massive (GP-GM). As above; broken gravel in spoon; blow counts may be overstated. 51011 111 111 212 213 025 101820 232318 5910 131718 21 2 2 3 4 7 38 41 19 35 Associated Earth Sciences, Inc. Exploration Boring EB-4 Renton High School ReplacementRenton, Washington Start Date: 4/9/2024 Logged By: BCY20210249E002Ending Date: 4/9/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):45.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):14.1 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 75 11 12 As above; broken gravel in spoon; blow counts may be overstated. Wet, brownish gray, gravelly, medium to coarse SAND, trace silt (SP). Groundwater encountered at 14.1 feet ATD. Practical auger refusal due to large gravel. 202221 231617 43 33 Associated Earth Sciences, Inc. Exploration Boring EB-4 Renton High School ReplacementRenton, Washington Start Date: 4/9/2024 Logged By: BCY20210249E002Ending Date: 4/9/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):45.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):14.1 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Asphalt - 3 inches / Base Course »4 to 6 inches FillSlightly moist, brown mixed with dark gray, silty, fine to medium SAND, some gravel; disturbed texture; fine organics (rootlets) (SM).Slightly moist, brown mixed with gray, silty, fine to coarse SAND, some gravel (SM). Black River AlluviumLower 3 inches: Moist, gray with occasional oxidation staining to orange, sandy, SILT (ML).Moist, brown and gray with faint oxidation staining, fine sandy, SILT; stratified; occasional interbed of brown, silty, fine sand (ML).Moist, orange brown, silty, fine SAND; transitioning to gray with minor oxidation staining, silty, fine sand at tip of spoon (SM).Wet, brown to orange brown, silty, fine SAND; occasional gray, silty interbed; faintly stratified (SM). Wet, gray with some brown, very sandy, GRAVEL, some silt; gravel the full diameter of sampler present; blow counts may be slightly overstated (GP- GM).Driller notes increase in gravel. Cedar River AlluviumDriller adding drilling fluid. Wet, gray, fine SAND, some silt with a layer of GRAVEL, some fine to coarse sand, trace silt at bottom of spoon (SP-SM). Wet, gray, gravelly, fine to medium SAND, trace silt; poor recovery; broken gravel in sampler; blow counts likely overstated (SP). Wet, gray, sandy, GRAVEL; poor recovery; pushing rock at tip of sampler (GW). Wet, gray to brownish gray, sandy, GRAVEL, trace silt; broken gravel in sampler; blow count overstated (GW). 797 1023 111 234 257 51014 81417 22023 201917 162131 16 5 2 7 12 24 31 43 36 52 Associated Earth Sciences, Inc. Exploration Boring EB-5 Renton High School ReplacementRenton, Washington Start Date: 4/11/2024 Logged By: BCY20210249E002Ending Date: 4/11/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):10 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 75 11 12 13 As above. Wet, brownish gray, medium SAND, trace silt; poor recovery; driller notes pushing gravel at tip of sample; blow counts overstated (SP). Wet, oxidized brown, silty, fine SAND; stratified with gray, medium SAND, trace gravel, some silt (SM). Groundwater encountered at 10 feet ATD. Practical auger refusal due to large gravel. 182320 192526 10811 43 51 19 Associated Earth Sciences, Inc. Exploration Boring EB-5 Renton High School ReplacementRenton, Washington Start Date: 4/11/2024 Logged By: BCY20210249E002Ending Date: 4/11/2024 Approved By: JHS Driller/Equipment: ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Ground Surface Elevation (ft):»34Hole Diameter (in):6 Datum:NAVD 88Groundwater Depth ATD (ft):10 Groundwater Depth Post Drilling (ft) (Date): () De p t h ( f t ) Sa m p l e T y p e Sa m p l e % R e c o v e r y Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Ot h e r T e s t s 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 0 5 10 15 20 25 30 35 1 2 3 4 5 6 7 8 9 10 Sod / Topsoil - 3 inches FillSlightly moist, dark brown, silty, fine SAND, trace to some gravel; abundant organics (rootlets) (SM).Slightly moist, gray, fine SAND; mixed with dark brown, silty, fine SAND; scattered organics (rootlets; broken gravel in spoon; blow counts may be overstated (SM).As above; slightly moist to moist, some gravel. Cedar River AlluviumSlightly moist, brown to grayish brown, sandy, GRAVEL, trace to some silt; rare organics (rootlets); gravel filled diameter of sampler; blow counts may be overstated (GP-GM).Slightly moist, brownish gray, sandy, GRAVEL, trace to some silt; broken gravel in spoon; blow counts may be overstated (GP-GM). Wet, gray to brownish gray, sandy to very sandy, GRAVEL, trace to some silt; rare organics (wood debris) (GP-GM). Wet, brownish gray, sandy, GRAVEL, trace silt; rare interbed (»2 inches thick) of fine sand, some silt; broken gravel in split spoon; blow counts may be overstated (GW). Wet, brown, GRAVEL, some fine to medium sand,trace silt; poor recovery; broken gravel in split spoon;blow counts may be overstated (GW). Wet, brown, fine to medium SAND, some silt, somegravel; broken gravel at tip of sample; blow countsmay be overstated (SP-SM). Wet, brown, fine to medium SAND, trace gravel; sampler was over filled and may contain heaved 156 568 61110 161819 182618 11811 101433 132425 132321 50/4" 11 14 21 37 44 19 47 49 44 50/4" Concrete 0 to 2 feet Bentonite chips 2 to 11 feet 2-inch I.D. PVC casing 0 to14.5 feet Sand 11 to 26 feet 2-inch I.D. PVC well screen 0.010-inch slot width 14.4 to 24.4 feet Well pointed end cap withthreads Slough 26 to 51.5 feet Associated Earth Sciences, Inc. Monitoring Well EB-6W Renton High School ReplacementRenton, Washington Start Date: 4/11/2024 Logged By: BCY20210249E002Ending Date: 4/11/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):26.5Hole Diameter (in):6 Well Tag No.:BPQ288Ground Surface Elevation (ft):»36 Top of Well Casing Elevation (ft):»35.8Water Level Elevation (ft):21.7 Datum:NAVD 88Groundwater Depth ATD (ft): 14.3 Groundwater Depth Post Drilling (ft) (Date): 14.1 ( 4/26/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 1 of 2 40 45 50 55 60 65 70 11 12 13 material; blow counts overstated (SP). Wet, fine to medium SAND, trace to some silt; becomes gravelly at bottom 3 inches (SP-SM). Wet, grayish brown, fine SAND, trace silt; occasional interbed (<3 inches thick) of brown, medium to coarse sandy, gravel (SP). Driller notes transition into gravel with heavy drill chatter. No recovery; attempted additional sample with Cal- Mod sampler, no recovery. Groundwater encountered at 14.3 feet ATD. Groundwater encountered at 14.1 feet on 4/26/ 24. Practical auger refusal due to large gravel. 101520 141610 101210 35 26 22 Associated Earth Sciences, Inc. Monitoring Well EB-6W Renton High School ReplacementRenton, Washington Start Date: 4/11/2024 Logged By: BCY20210249E002Ending Date: 4/11/2024 Approved By: JHS Driller/Equipment:ADT/D-50 Hollow Stem Auger Total Depth (ft):51.5Hammer Weight/Drop:140#/30"Well Completion Depth (ft):26.5Hole Diameter (in):6 Well Tag No.:BPQ288Ground Surface Elevation (ft):»36 Top of Well Casing Elevation (ft):»35.8Water Level Elevation (ft):21.7 Datum:NAVD 88Groundwater Depth ATD (ft): 14.3 Groundwater Depth Post Drilling (ft) (Date): 14.1 ( 4/26/24 ) De p t h ( f t ) Sa m p l e T y p e Sa m p l e N o . Gr a p h i c Sy m b o l Description Wa t e r L e v e l Bl o w s / 6 " Blows/Foot 1 0 2 0 3 0 4 0 5 0 + Well Construction 20 2 1 0 2 4 9 E 0 0 2 5/ 1 5 / 2 0 2 4 Sheet: 2 of 2 APPENDIX B CPT Logs CPT-01 CPT Contractor: In SItu EngineeringCUSTOMER: AESLOCATION: RentonJOB NUMBER: 20210249E002 OPERATOR: OkbayCONE ID: DDG1351TEST DATE: 4/9/2024 10:55:33 AMPREDRILL: 0 ftBACKFILL: 20% Bentonite slurry & ChipsSURFACE PATCH: Cold Patch TOTAL DEPTH: 34.121 ft Depth(ft) Tip COR(tsf) 0 10000 5 10 15 20 25 30 35 40 Sleeve Stress(tsf) 08 F.Ratio(%) 0 5 Pore Pressure(psi) -5 35 SBT FR(RC 1983) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT(blows/ft) 0 120 CPT-02 CPT Contractor: In SItu EngineeringCUSTOMER: AESLOCATION: RentonJOB NUMBER: 20210249E002 OPERATOR: OkbayCONE ID: DDG1351TEST DATE: 4/9/2024 12:48:08 PMPREDRILL: 0 ftBACKFILL: 20% Bentonite slurry & ChipsSURFACE PATCH: Cold Patch TOTAL DEPTH: 25.262 ft Depth(ft) Tip COR(tsf) 0 10000 5 10 15 20 25 30 F.Ratio(%) 0 5 Pore Pressure(psi) -10 15 SBT FR(RC 1983) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT(blows/ft) 0 100 Seismic Velocity(ft/s) 0 1800 HOLE NUMBER: CPT-02 OPERATOR: Okbay CUSTOMER: LOCATION: Renton JOB NUMBER: 20210249E002 CPT Contractor: In SItu Engineering CONE ID: DDG1351 TEST DATE: 4/9/2024 12:48:08 PM PREDRILL0 ft BACKFILL: 20% Bentonite slurry & Chips SURFACE PATCH: Cold Patch HOLE NUMBER: CPT-02 Depth 3.77ftRef*Arrival 6.68mSVelocity* Depth 7.05ftRef 3.77ft Arrival 9.80mSVelocity 937.72ft/S Depth 13.45ftRef 7.05ft Arrival 13.67mSVelocity 1597.86ft/S Depth 20.01ftRef 13.45ft Arrival 19.80mSVelocity 1056.58ft/S 0 10 20 30 40 50 60 70 80 90 100 Depth 25.26ftRef 20.01ft Arrival 25.55mSVelocity 908.07ft/S Time (mS) Hammer to Rod String Distance (ft): 2.62* = Not Determined CPT-03 CPT Contractor: In SItu EngineeringCUSTOMER: AESLOCATION: RentonJOB NUMBER: 20210249E002 OPERATOR: OkbayCONE ID: DDG1351TEST DATE: 4/9/2024 1:59:11 PMPREDRILL: 0 ftBACKFILL: 20% Bentonite slurry & ChipsSURFACE PATCH: Cold Patch TOTAL DEPTH: 20.505 ft Depth(ft) Tip COR(tsf) 0 10000 5 10 15 20 25 30 35 40 Sleeve Stress(tsf) 08 F.Ratio(%) 0 5 Pore Pressure(psi) -5 35 SBT FR(RC 1983) 1 sensitive fine grained 2 organic material 3 clay 4 silty clay to clay 5 clayey silt to silty clay 6 sandy silt to clayey silt 7 silty sand to sandy silt 8 sand to silty sand 9 sand 10 gravelly sand to sand 11 very stiff fine grained (*) 12 sand to clayey sand (*) *SBT/SPT CORRELATION: UBC-1983 0 12 SPT(blows/ft) 0 120 APPENDIX C Historical Exploration Logs (AESI, 1999, 2009, 2024) 0 5 10 15 20 25 30 35 100% 60% 50% 40% 1 2 3 4 0800 0845 0823 FillCuttings are brownish gray, gravelly, silty, SAND; occasional organics (fine wood); rounded gravel; driller reports caving to 10 feet (SM). Holocene AlluviumCuttings are gray, silty, fine to medium SAND, trace coarse sand (SM). Chatter and bouncing; driller reports increased cavedmaterial at 20 feet. Cuttings are gray, medium to coarse sandy, SILT;occasional gravel; organics (roots); drill action smoothes(ML). Cuttings are gray, medium to coarse sandy, SILT; occasional broken gravel (ML). Driller notes increased drill action at 30 feet; driller adds water and bentonite. Chatter and bouncing increase. Geothermal test loop was not installed; hole backfilled with bentonite grout. Associated Earth Sciences, Inc. Exploration Boring GTL-1 Renton High School ReplacementRenton, Washington Start Date: 10/1/24 Logged By: RPW20210249E002Ending Date: 10/7/2024 Approved By: JHS Driller/Equipment:Gregory/Track Mounted Mud RotaryHole Dia. (in):6 Total Depth (ft):70Ground Surface Elevation (ft):»32 Water Level Elevation (ft):N/A (mud rotary)Groundwater Depth ATD (ft): N/A (mud rotary) Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 1 of 2 40 45 50 55 60 65 70 100% 20% 0% 100% 20% 5 6 7 0833 1234 1305 0800 1430 1100 1445 Cuttings are grayish brown to orangish brown, silty, coarse SAND; occasional fine to medium sand; broken gravel (SM). Loud chatter; driller reports bouncing; lost a large amount of water (»2,200 gallons); driller adds water and bentonite. Driller notes loss in circulation; no sample recovered; driller decides to advance casing to combat caving and water loss (»3,200 gallons). Cuttings are grayish brown, silty, medium to coarse SAND, trace fine sand; gravel content understated by lack of circulation (SM). Cuttings are gray, SILT, trace fine sand; driller notes no circulation, losing water rapidly; gravel contentunderstated by lack of circulation (ML). Abandoned hole due to difficult gravelly drilling conditions and loss of water/ drilling fluid circulation. Driller efforts to advance from 50 to 70 feet took 2 days with two separate drill rigs. Associated Earth Sciences, Inc. Exploration Boring GTL-1 Renton High School ReplacementRenton, Washington Start Date: 10/1/24 Logged By: RPW20210249E002Ending Date: 10/7/2024 Approved By: JHS Driller/Equipment:Gregory/Track Mounted Mud RotaryHole Dia. (in):6 Total Depth (ft):70Ground Surface Elevation (ft):»32 Water Level Elevation (ft):N/A (mud rotary)Groundwater Depth ATD (ft): N/A (mud rotary) Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 2 of 2 0 5 10 15 20 25 30 35 N/A N/A N/A N/A 1 2 3 4 2/20 0934 0941 0948 0956 1015 1026 1035 Topsoil/Sod - 3 inches FillDriller uses air rotary to advance casing down to 100 feet. Cuttings are brown, fine sandy, SILT; occasional orange oxidation staining; driller notes easy drilling (ML). Holocene Alluvium Dark brown, silty, gravelly, medium to coarse SAND, silt coats gravel; broken gravel (SM-GM). Driller reports heaving sand and gravel within the casing. Driller reports heaving sand and gravel at 22 feet; increase in difficult drilling. Wet, brown, gravelly, fine to medium SAND, trace coarsesand; broken gravel (SP-GP). Increased drill chatter and bouncing; cuttings brown at 25 feet. Cuttings are wet, brown, silty, fine to medium SAND; occasional organics (1/4 to 1/2-inch wood debris); 1-inch diameter Centennial CenFuse IPS SDR11 polyethylene flexible pipe loop with fused connector at baseGeothermal loop extends from 0 to 301 feetBentonite grout 0 to 301 feet Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 1 of 9 40 45 50 55 60 65 70 N/A N/A N/A N/A 5 6 7 8 1043 1051 1106 1113 1145 1155 1241 1258 broken gravel (SM). Increasing chatter and bouncing from 38 to 110 feet. Increased groundwater coming out of the cuttings; color is oxidized orange brown; drill bit grinding on gravel. Cuttings are wet, oxidized brown, gravelly, medium to coarse SAND, fine sand; broken gravel; water color changing from light brown to brown/oxidized orange brown; increasing bouncing and drill chatter (SP). Drill bouncing on gravel at 48 feet; water becomes dark brown). Increasing chatter; bouncing on gravel at 53 and 55 feet. Cuttings are wet, gray to dark brownish gray, medium to coarse sandy, GRAVEL; broken gravel; water is dark brown or brown (GP). Jumping on gravel; hard drilling; increased chatter at 62feet. Cuttings are as above; increased chatter; slow advancing. Water is oxidized brown color. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 2 of 9 75 80 85 90 95 100 105 N/A N/A N/A 100% 80% 70% 9 10 11 1325 1333 1411 1421 2/20 1530 0947 2/21 Cuttings are as above; water is oxidized brown. Drill chatter and bouncing on cobble or gravel at 82 feet. Drill chatter decreases from 84 to 90 feet. Cuttings are as above; gravel content decreases; sand size decreases to fine to medium sand with occasional coarse sand and gravel. Water becomes dark brown and grain size of sand and gravel increases at 92 feet.Drill chatter and action increasing at 93 feet. Driller reports bouncing on gravel or cobble; chatterincreases and drill action increases 96 to 99 feet. Driller switches to a tricone bit and a mud-rotary configuration. Driller reports no cuttings due to drilling in gravel and cobbles and loss of circulation.Driller reports caving around 100 to 110 feet within the borehole. Bouncing on gravel at 107 feet; driller reportsencountering silty deposit at 108 feet.Tukwila Formation: Siltstone ? Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 3 of 9 110 115 120 125 130 135 140 145 70% 70% 60% 50% 30% 30% 10% 12 13 14 15 1015 1040 1114 1115 1219 1220 1317 1319 Cuttings are light gray, fine sandy, SILT, trace coarse sand(ML). Cuttings are dark gray, fine sandy, SILT, driller reports increase in torque from 107 feet to 125 feet; driller pulled the rods at 125 feet to switch back to the tricone bit; driller reports difficulty getting through the hard silt with drag bit (ML). Cuttings are as above; trace gravel. Driller states torque and chatter increasing at 137 feet and bouncing on gravel. Cuttings are as above. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 4 of 9 150 155 160 165 170 175 180 16 17 18 19 2/21 1450 0737 2/24 0751 0753 0800 0801 0808 0809 Driller began to trip out. Drill action increases; difficult drilling from 153 to 177. Cuttings are brownish gray, SILT, trace fine sand, trace coarse sand; relatively easy drilling (ML). Drill action smooth from 160 to 170 feet. Cuttings are gray, SILT, fine to very fine sand, tracebroken coarse sand and gravel (ML). Cuttings are as above; fine sand content increases to very fine to fine sandy, SILT (ML). Smooth drilling from 180 to 184 feet. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 5 of 9 185 190 195 200 205 210 215 10% 30% 30% 60% 60% 60% 60% 20 21 22 0816 0817 0956 0957 1014 1015 Drill action increased; lost circulation into formation at 184 feet; driller adds water and polymer.Cuttings are gray, fine sandy, SILT; occasional gravel and broken gravel. Drill action smooth 190 to 192 feet. Driller reports losing circulation at 192 feet; drill action/ stuck rods; chatter increases; driller increased saw dust due to loss in water; tried again but lost all the water within 10 minutes at bottom. Driller states they will trip in and out to build a "layer of cake" of saw dust and polymer within the borehole. Cuttings are gray, SILT, trace very fine sand; broken gravel; poor recovery; easy drill action (ML). Driller reports rough drilling; increased chatter. Cuttings are light gray, SILT, trace fine sand, brokengravel (ML). Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 6 of 9 220 225 230 235 240 245 250 60% 60% 60% 60% 60% 60% 60% 23 24 25 26 1027 1028 1038 1038 1100 1100 1110 1112 Easy drilling; contractor reports jumping on gravel 222 to 223 feet. Cuttings are light gray to bluish gray, silty, medium SAND; sand comprised of broken gravel and coarse sand; easy drill action; driller reports drill torque increased but no loss in drilling fluid (SM). Cuttings are grayish, brown to gray, fine sandy, SILT, trace coarse sand; easy but slow drilling (ML).Driller reports hard, slow drilling. Cuttings are as above. Drilling slow; driller reports hard unit. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 7 of 9 255 260 265 270 275 280 285 290 27 28 29 30 1147 1149 1220 1222 1307 1308 1338 1340 Increase in coarse sand. Driller reports minimal fluid loss; slow drilling. Cuttings are as above. Slow drilling at 272 feet. Cuttings are as above. Slow drilling 280 to 290 feet. Very slow drilling 284 to 288 feet. Cutting fluid remains a grayish brown; driller adds water. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 8 of 9 295 300 305 310 315 320 325 60% 50% 2/24 1358 Cuttings are dark gray, silty, medium SAND; sand consists of broken gravel and coarse sand (SM). Driller reports increase in drill action and loss of drilling fluid; driller adds polymer, sawdust, and water. Groundwater encountered at 20 feet ATD. Driller completed the borehole on 2/24/25, but due to caving at approximately 110 feet BGS, the driller advanced 10 more feet of casing down to a total depth of 110 feet. The driller then advanced their drill rods down to 301 feet and back out before successfully installing the geothermal test loop on 2/ 25/25. Associated Earth Sciences, Inc. Exploration Boring GTL-2 Renton High School ReplacementRenton, Washington Start Date: 2/20/25 Logged By: RPW20210249E002Ending Date: 2/24/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):301Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»12.5Groundwater Depth ATD (ft): 20 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 9 of 9 0 5 10 15 20 25 30 35 1 2 3 4 2/26 0926 0949 1052 1100 1108 1113 1119 Asphalt - 4 inches FillCuttings are brownish, sandy, SILT; occasional organics (leaves, moss and sticks from asphalt); driller began driving casing with an underreamer bit (ML). Holocene Alluvium Grayish brown, silty, fine to medium SAND; trace rounded gravel (SM). Silt content increases; sand size decreases; brown, medium to coarse sandy, SILT; occasional fine gravel (ML). Easy drilling 20 to 30 feet. Driller reports increased drill action at 25 feet. Cuttings are brownish, sandy, SILT, some fine gravel(ML). Cuttings become dark gray, gravelly, medium to coarse SAND; silt coating sand and gravel clasts; broken gravel; trace organics (1 to 2 inch wood debris); relatively rounded gravel (SP-SM). Geothermal test was not installed; hole backfilled with bentonite grout. Associated Earth Sciences, Inc. Exploration Boring GTL-3 Renton High School ReplacementRenton, Washington Start Date: 2/26/25 Logged By: RPW20210249E002Ending Date: 2/27/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):125Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»2Groundwater Depth ATD (ft): 30 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 1 of 4 40 45 50 55 60 65 70 5 6 7 8 1124 1135 1141 1149 1156 1203 1210 1216 Cuttings become brown; relatively easy drilling 40 to 45 feet.Cuttings are gray, silty, fine to medium SAND, trace coarse sand; broken gravel; gravel rounded (SM). Cuttings increase with water; driller reports heaving conditions; moderate drilling difficulty. Cuttings water becomes oxidized brown. Cuttings are dark grayish brown, gravelly, medium to coarse SAND, trace silt; broken gravel and coarse sand (SP-GP). Cuttings become gray, sandy, SILT; interbed? (ML). Cuttings become gray with decrease in gravel; relatively easy drilling from 60 to 70 feet but low sample recovery. Cuttings are gray, fine sandy, SILT, trace broken gravel (ML). Cuttings are dark oxidized orangish gray, gravelly,medium to coarse SAND; broken gravel and sand;angular sand; cuttings water is oxidized brown; drillerstates heaving conditions; rough drilling from 70 feet; Associated Earth Sciences, Inc. Exploration Boring GTL-3 Renton High School ReplacementRenton, Washington Start Date: 2/26/25 Logged By: RPW20210249E002Ending Date: 2/27/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):125Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»2Groundwater Depth ATD (ft): 30 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 2 of 4 75 80 85 90 95 100 105 9 10 11 1231 1237 1301 1312 1338 1343 2/26 increased drill action and chatter (SP). Cuttings are oxidized brown gray, medium to coarsesandy, GRAVEL; moderately difficult drilling to 80 feet;increased chatter (GP). Chatter and drill action increases from 80 to 90 feet. Cuttings are brownish dark gray, gravelly, medium to coarse SAND to sandy, GRAVEL; broken gravel and sand (SP-GP). Driller chatter, action, and difficulty increases. Cuttings are as above. Cuttings are brown gray; increased chatter and drill action. Cuttings are dark gray, medium to coarse, sandy, fine GRAVEL; broken coarse sand and gravel; cuttings water is light/tan brown (GP). Associated Earth Sciences, Inc. Exploration Boring GTL-3 Renton High School ReplacementRenton, Washington Start Date: 2/26/25 Logged By: RPW20210249E002Ending Date: 2/27/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):125Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»2Groundwater Depth ATD (ft): 30 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 3 of 4 110 115 120 125 130 135 140 145 12 13 1500 0832 2/27 0940 0942 2/27 Driller reports broken shoe; will begin mud rotary drilling due to broken shoe; begins advance with tricone bit; increased chatter at 112 feet. No sample recovered due to lack of circulation. Difficult drilling conditions; driller reports increasedchatter and bit bouncing on gravel at 120 feet. Driller reports caving gravel could cause issues removing drill rod and abandons the hole. Groundwater encountered at 30 feet. Associated Earth Sciences, Inc. Exploration Boring GTL-3 Renton High School ReplacementRenton, Washington Start Date: 2/26/25 Logged By: RPW20210249E002Ending Date: 2/27/25 Approved By: JHS Driller/Equipment:GeoTility/Pickup Mounted Air/Mud RotaryHole Dia. (in):4 Total Depth (ft):125Ground Surface Elevation (ft):»32 Water Level Elevation (ft):»2Groundwater Depth ATD (ft): 30 Datum:NAVD 88 De p t h ( f t ) Fl u i d V o l u m e Ru n N o . & L e n g t h %R e c o v e r y Ru n T i m e Sa m p l e Ot h e r T e s t s & S a m p l e s Gr a p h i c Sy m b o l Description Wa t e r L e v e l Well Construction 20 2 1 0 2 4 9 E 0 0 2 4/ 2 5 / 2 0 2 5 Sheet: 4 of 4 APPENDIX D Hydrograph ASSOCIATED EARTH SCIENCES, INC. Groundwater Hydrograph Renton High School Replacement Renton, Washington AESI Project No. 20210249E002 06/2025 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 18 19 20 21 22 23 24 25 26 27 28 04 / 0 1 / 2 4 05 / 2 1 / 2 4 07 / 1 0 / 2 4 08 / 2 9 / 2 4 10 / 1 8 / 2 4 12 / 0 7 / 2 4 01 / 2 6 / 2 5 03 / 1 7 / 2 5 05 / 0 6 / 2 5 06 / 2 5 / 2 5 08 / 1 4 / 2 5 Ra i n f a l l ( i n c h e s ) Ap p r o x i m a t e G r o u n d w a t e r E l e v a t i o n ( f e e t ) EB-1W EB-1W Dl.EB-3W EB-3W DL EB-6W EB-6W Dl.Daily Rainfall Note: Black and white reproduction of this color original may reduce its effectiveness and lead to incorrect interpretation. Note: Well elevations are based on 2021 King County LIDAR contour elevations. APPENDIX E Laboratory Test Results Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 0.8 2.4 4.5 21.1 71.2 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-1W Depth: 5' Client: Project: Project No:Figure sandy SILT trace gravel 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 99.2 97.7 96.8 94.1 92.3 89.4 78.3 71.2 68.9 NP NV ML A-4(0) 0.2603 0.2007 5-2-2024 5-6-2024 FEW BCY/BD 4-9-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 9.7 3.2 52.3 29.3 5.5 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-1W Depth: 35' Client: Project: Project No:Figure SAND some gravel some silt 3/4" 5/8" 1/2" 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 98.2 96.3 94.4 90.3 87.7 87.1 76.0 34.8 16.0 8.4 5.5 4.8 NP NV SP-SM A-1-b 4.4290 1.1970 0.6359 0.5454 0.3854 0.2391 0.1757 3.62 1.33 5-2-2024 5-6-2024 FEW BCY/BD 4-9-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 8.7 5.8 14.0 48.3 23.2 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-2 Depth: 2.5 Client: Project: Project No:Figure silty SAND some gravel 5/8" 1/2" 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 99.1 96.9 91.3 86.5 85.5 79.0 71.5 57.3 33.4 23.2 18.5 NP NV SM A-2-4(0) 3.9921 1.8638 0.2678 0.2143 0.1337 5-2-2024 5-6-2024 FEW BCY/BD 4-10-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 6.5 2.7 7.6 58.5 24.7 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-3W Depth: 2.5' Client: Project: Project No:Figure silty SAND some gravel 5/8" 1/2" 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 97.0 95.6 93.5 91.8 90.8 87.2 83.2 74.8 42.1 24.7 21.8 NP NV SM A-2-4(0) 1.7106 0.6009 0.1961 0.1700 0.1094 5-2-2024 5-6-2024 FEW BCY/BD 4-10-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 0.0 1.3 7.5 8.3 45.3 37.6 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-3W Depth: 7.5' Client: Project: Project No:Figure very silty SAND trace gravel 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 98.7 93.1 91.2 85.3 82.9 74.6 50.6 37.6 33.4 NP NV SM A-4(0) 1.7935 0.7866 0.1833 0.1478 5-2-2024 5-6-2024 FEW BCY/BD 4-10-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 6.1 29.0 12.2 17.5 21.7 13.5 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-4 Depth: 0' Client: Project: Project No:Figure very gravelly silty SAND 1" 3/4" 5/8" 1/2" 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 93.9 91.4 86.6 78.2 64.9 54.5 52.7 43.0 35.2 28.5 19.0 13.5 11.4 NP NV SM A-1-b 14.6977 12.0069 3.4925 1.5709 0.2751 0.0988 5-2-2024 5-6-2024 FEW BCY/BD 4-9-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0 0.0 0.0 1.5 8.6 72.3 17.6 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-5 Depth: 10' Client: Project: Project No:Figure silty SAND #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 98.7 98.5 97.0 89.9 47.5 28.0 17.6 15.0 NP NV SM A-2-4(0) 0.4285 0.3938 0.2928 0.2590 0.1645 5-2-2024 5-6-2024 FEW BCY/BD 4-11-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) Particle Size Distribution Report PE R C E N T F I N E R 0 10 20 30 40 50 60 70 80 90 100 GRAIN SIZE - mm. 0.0010.010.1110100 % +3"Coarse % Gravel Fine Coarse Medium % Sand Fine Silt % Fines Clay 0.0 11.1 38.5 10.6 19.2 14.9 5.7 6 i n . 3 i n . 2 i n . 1½ i n . 1 i n . ¾ i n . ½ i n . 3/ 8 i n . #4 #1 0 #2 0 #3 0 #4 0 #6 0 #1 0 0 #1 4 0 #2 0 0 TEST RESULTS Opening Percent Spec.*Pass? Size Finer (Percent) (X=Fail) Material Description Atterberg Limits (ASTM D 4318) Classification Coefficients Date Received:Date Tested: Tested By: Checked By: Title: Date Sampled:Location: Onsite Sample Number: EB-6W Depth: 15' Client: Project: Project No:Figure very sandy GRAVEL some silt 1.5" 1" 3/4" 5/8" 1/2" 3/8" #4 #8 #10 #20 #40 #60 #100 #200 #270 100.0 92.6 88.9 75.8 69.9 62.2 50.4 41.4 39.8 31.6 20.6 12.4 8.5 5.7 5.0 NP NV GP-GM A-1-a 20.9579 17.9683 8.7323 4.6103 0.7568 0.3037 0.1918 45.52 0.34 5-2-2024 5-6-2024 FEW BCY/BD 4-11-2024 Renton School District No. 403 Renton High School 20210249 E002 PL=LL=PI= USCS (D 2487)=AASHTO (M 145)= D90=D85=D60= D50=D30=D15= D10=Cu=Cc= Remarks *(no specification provided) APPENDIX F Liquefaction Analysis Results Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-1W Water Depth=5 ft Surface Elev.=32 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 40 125 12 3 105 35 2 100 70 2 100 70 4 105 30 2 100 70 6 105 70 8 110 5 14 115 5 15 115 5 27 125 5 42 125 2 41 125 2 Fill Black River Alluvium Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 11.04 in. 0 (in.) 50 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-2 Water Depth=5 ft Surface Elev.=34 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 17 120 25 7 110 25 4 105 10 5 105 90 3 105 90 4 105 90 29 125 5 35 125 5 7 110 5 22 120 25 31 125 10 53 125 10 34 125 25 Fill Black River Alluvium Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 6.97 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-3W Water Depth=5 ft Surface Elev.=38 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 17 115 25 4 105 25 2 100 90 7 110 50 16 115 25 4 110 10 26 125 25 32 125 25 34 125 5 17 120 5 41 125 5 20 120 5 44 125 7 Fill Black River Alluvium Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 7.12 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-4 Water Depth=5 ft Surface Elev.=34 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 21 120 25 2 100 25 2 100 60 3 105 80 4 105 70 7 105 10 38 125 5 41 125 5 19 120 10 35 125 10 43 125 10 33 125 5 Fill Black River Alluvium Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 6.82 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-5 Water Depth=5 ft Surface Elev.=34 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 21 120 25 5 105 25 2 100 70 7 110 25 12 110 25 24 125 10 31 125 5 43 125 3 36 125 5 52 125 5 43 125 5 51 125 25 15 120 10 Fill Black River Alluvium Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 3.90 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=EB-6W Water Depth=5 ft Surface Elev.=36 Magnitude=7.0 Acceleration=0.677g (ft)0 10 20 30 40 50 60 70 11 110 25 14 115 25 21 120 25 37 125 5 44 125 5 19 120 5 37 125 5 49 125 5 44 125 10 50 125 3 35 125 10 26 125 5 22 120 5 Fill Cedar River Alluvium Raw Unit FinesSPT Weight %Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 2.09 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=CPT-01 Water Depth=5 ft Surface Elev.=32 Magnitude=7.0 Acceleration=0.677g (ft)0 5 10 15 20 25 30 35 Fill Black River Alluvium Cedar River Alluvium Shear Stress Ratio CRR CSR fs1 Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement Saturated Unsaturat. S = 1.79 in. 0 (in.) 10 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=CPT-02 Water Depth=5 ft Surface Elev.=36 Magnitude=7.0 Acceleration=0.677g (ft)0 5 10 15 20 25 30 35 Fill Cedar River Alluvium Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 0.85 in. 0 (in.) 1 fs1=1 Liq u e f y P r o C i v i l T e c h S o f t w ar e U S A w w w . c i v i l t e c h . c o m CivilTech Corporation LIQUEFACTION ANALYSIS Renton High School Plate A-1 Hole No.=CPT-03 Water Depth=5 ft Surface Elev.=34 Magnitude=7.0 Acceleration=0.677g (ft)0 5 10 15 20 25 30 35 Fill Black River Alluvium Shear Stress Ratio CRR CSR fs1Shaded Zone has Liquefaction Potential 01 Soil DescriptionFactor of Safety051Settlement SaturatedUnsaturat. S = 1.35 in. 0 (in.) 10 fs1=1 APPENDIX G Shear Wave Velocity Survey (WSG, 2020) WASHINGTON 2019–2021 SCHOOL SEISMIC SAFETY PROJECT SITE CLASS ASSESSMENT See Washington Geological Survey Open File Report 2019-01 for more information. RENTON HIGH SCHOOL Location of seismic array at the school campus. Liquefaction Moderate to high RENTON SCHOOL DISTRICT, KING COUNTY, WA WHAT IS SITE CLASS? Site class estimates how local soils amplify earthquake- induced ground shaking, and is based on how fast seismic (shear) waves travel through the upper 30 m (100 ft) of the soil (Vs30). Site class has been approximated for the entire State of Washington, but these predictions aren’t always accurate where geology is complex. The site class measured for this project accounts for geologic complexity and is therefore more accurate. HOW DID WE MEASURE SITE CLASS? On October 15, 2020, a team from the Washington Geological Survey conducted a seismic survey at Renton High School. We measured Vs30 by laying out 48 geophones (ground motion sensors) in a 94 m (308 ft) array. Then we conducted (1) an active survey in which a sledgehammer was struck against the ground to generate seismic waves; and (2) a passive survey where we measured ambient seismic noise. These surveys let us calculate Vs30 at the center of the array, which is then correlated to site class using the table below. It is generally accurate to assume the site class is the same under the array and the school. WHAT DID WE LEARN? □The school is built on stiff soil, which would amplify ground shaking relative to rock. □Site class is within the predicted site class of D–E.WHAT SOILS ARE UNDER THE SCHOOL? The school is sitting on urban or industrial land modified by widespread or discontinuous artificial fill. GEOLOGIC HAZARDS AT THE SCHOOL Ground Shaking Violent MEASURED SITE CLASS D Site class Description Vs30 (m/sec) Ground shaking amplification A Hard rock >1,500 Low B Rock 760–1,500 C Soft rock or very dense soil 360–760 D Stiff soil 180–360 E Soft soil <180 High TECHNICAL OVERVIEW OF RESULTS QUESTIONS?Washington Department of Natural Resources—WA Geological Survey geology@dnr.wa.gov • 360.902.1450 • https://www.dnr.wa.gov/geology RENTON HIGH SCHOOL—ICOS# 21354 This section provides a technical overview of the geophysical methods and results of the seismic site characterization. DISPERSION CURVE The term dispersion image refers to the image of phase velocity versus frequency of a record. Dispersion curve refers to the manually picked fundamental mode in a dispersion image. The multi-channel analysis of surface wave (MASW) dispersion images from the forward and reverse directions are poor quality, but the fundamental mode can be picked with some confidence. However, the microtremor analysis method (MAM) dispersion image is excellent quality, so that the fundamental mode can be picked with high confidence. MAM and the forward and reverse MASW dispersion curves correlate well, depicting similar trends. Therefore the three dispersion curves are combined into a single model. VELOCITY MODEL An initial model was generated using the 1/3 wavelength approximation and the combined dispersion curves. The initial model had an RMSE of 12.9 percent. The inversion was carried out for ten iterations and resulted in a final model with an RMSE of 4.7 percent. The final model is unconstrained in the top 1 m (3 ft), and below this shows rapidly increasing velocity to 6 m (20 ft), then generally increasing velocity down to 30 m (100 ft). Our best Vs30 measurement is 272 m/sec, which places the site solidly in the D site class. This is within the predicted site class of D–E. Final inverted velocity model with measured dispersion curve and modeled dispersion curve. The equation used to calculate the average shear wave velocity (Vs) for the upper 30 m is shown in the upper right corner. di = thickness of any layer between 0 and 30 m. Vsi = shear wave velocity in m/sec of the layer. APPENDIX H Wellhead Protection Zone Map City of Renton GIS Mapping for Wellhead Protection Area Zones Proposed Renton High School Replacement/Expansion Area Technical Information Report New Renton High School Project No. 2230388.10 Appendix C Flow Control Calculations WWHM2012 PROJECT REPORT APPENDIX C FLOW CONTROL CALCULATIONS Flow control 6/3/2026 9:26:05 AM Page 2 General Model Information WWHM2012 Project Name:Flow control Site Name: Site Address: City: Report Date:6/3/2026 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2025/05/13 Version:4.3.2 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Flow control 6/3/2026 9:26:05 AM Page 3 Landuse Basin Data Predeveloped Land Use TDA 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.31 Pervious Total 0.31 Impervious Land Use acre ROADS FLAT 1.06 Impervious Total 1.06 Basin Total 1.37 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 Flow control 6/3/2026 9:26:05 AM Page 4 TDA 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 10.57 Pervious Total 10.57 Impervious Land Use acre ROADS FLAT 17.88 Impervious Total 17.88 Basin Total 28.45 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Flow control 6/3/2026 9:26:05 AM Page 5 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 2.08 Pervious Total 2.08 Impervious Land Use acre ROADS FLAT 4.89 Impervious Total 4.89 Basin Total 6.97 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 3 POC 3 Flow control 6/3/2026 9:26:05 AM Page 6 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.49 Pervious Total 0.49 Impervious Land Use acre ROADS FLAT 0.68 Impervious Total 0.68 Basin Total 1.17 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 Flow control 6/3/2026 9:26:05 AM Page 7 Basin 2A Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 8.17 Pervious Total 8.17 Impervious Land Use acre ROADS FLAT 13.95 Impervious Total 13.95 Basin Total 22.12 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Flow control 6/3/2026 9:26:05 AM Page 8 Basin 2B Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.06 Pervious Total 1.06 Impervious Land Use acre ROADS FLAT 5.61 Impervious Total 5.61 Basin Total 6.67 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: Tank 2B Tank 2B Flow control 6/3/2026 9:26:05 AM Page 9 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.15 Pervious Total 1.15 Impervious Land Use acre ROADS FLAT 5.69 Impervious Total 5.69 Basin Total 6.84 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 3 POC 3 Flow control 6/3/2026 9:26:05 AM Page 10 Routing Elements Predeveloped Routing Flow control 6/3/2026 9:26:05 AM Page 11 Mitigated Routing Tank 2B Dimensions Depth:5 ft. Tank Type:Circular Diameter:5 ft. Length:672 ft. Discharge Structure Riser Height:4.5 ft. Riser Diameter:24 in. Notch Type:Rectangular Notch Width:0.833 ft. Notch Height:0.750 ft. Orifice 1 Diameter:5.500 in.Elevation:0.5 ft. Element Outlets: Outlet 1 Outlet 2 Outlet Flows To: Tank Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.000000 0.000000 0.000 0.000 0.0556 0.016171 0.000600 0.000 0.000 0.1111 0.022740 0.001692 0.000 0.000 0.1667 0.027692 0.003098 0.000 0.000 0.2222 0.031792 0.004753 0.000 0.000 0.2778 0.035337 0.006620 0.000 0.000 0.3333 0.038482 0.008672 0.000 0.000 0.3889 0.041317 0.010890 0.000 0.000 0.4444 0.043903 0.013259 0.000 0.000 0.5000 0.046281 0.015765 0.000 0.000 0.5556 0.048482 0.018398 0.193 0.000 0.6111 0.050530 0.021149 0.273 0.000 0.6667 0.052442 0.024010 0.335 0.000 0.7222 0.054232 0.026973 0.387 0.000 0.7778 0.055913 0.030033 0.432 0.000 0.8333 0.057493 0.033184 0.473 0.000 0.8889 0.058981 0.036420 0.511 0.000 0.9444 0.060384 0.039736 0.547 0.000 1.0000 0.061708 0.043128 0.580 0.000 1.0556 0.062957 0.046591 0.611 0.000 1.1111 0.064136 0.050122 0.641 0.000 1.1667 0.065249 0.053716 0.670 0.000 1.2222 0.066299 0.057370 0.697 0.000 1.2778 0.067288 0.061081 0.724 0.000 1.3333 0.068221 0.064846 0.749 0.000 1.3889 0.069098 0.068660 0.773 0.000 1.4444 0.069922 0.072522 0.797 0.000 1.5000 0.070695 0.076429 0.820 0.000 1.5556 0.071419 0.080376 0.843 0.000 1.6111 0.072095 0.084363 0.865 0.000 1.6667 0.072724 0.088386 0.886 0.000 1.7222 0.073307 0.092443 0.907 0.000 1.7778 0.073846 0.096530 0.927 0.000 1.8333 0.074342 0.100647 0.947 0.000 Flow control 6/3/2026 9:26:05 AM Page 12 1.8889 0.074795 0.104790 0.967 0.000 1.9444 0.075206 0.108957 0.986 0.000 2.0000 0.075577 0.113145 1.005 0.000 2.0556 0.075906 0.117353 1.023 0.000 2.1111 0.076196 0.121579 1.041 0.000 2.1667 0.076446 0.125819 1.059 0.000 2.2222 0.076657 0.130072 1.077 0.000 2.2778 0.076830 0.134336 1.094 0.000 2.3333 0.076963 0.138608 1.111 0.000 2.3889 0.077059 0.142886 1.128 0.000 2.4444 0.077116 0.147169 1.144 0.000 2.5000 0.077135 0.151454 1.160 0.000 2.5556 0.077116 0.155739 1.176 0.000 2.6111 0.077059 0.160022 1.192 0.000 2.6667 0.076963 0.164300 1.208 0.000 2.7222 0.076830 0.168573 1.223 0.000 2.7778 0.076657 0.172836 1.238 0.000 2.8333 0.076446 0.177089 1.253 0.000 2.8889 0.076196 0.181330 1.268 0.000 2.9444 0.075906 0.185555 1.283 0.000 3.0000 0.075577 0.189763 1.297 0.000 3.0556 0.075206 0.193952 1.312 0.000 3.1111 0.074795 0.198119 1.326 0.000 3.1667 0.074342 0.202261 1.340 0.000 3.2222 0.073846 0.206378 1.354 0.000 3.2778 0.073307 0.210466 1.368 0.000 3.3333 0.072724 0.214522 1.381 0.000 3.3889 0.072095 0.218545 1.395 0.000 3.4444 0.071419 0.222532 1.408 0.000 3.5000 0.070695 0.226480 1.421 0.000 3.5556 0.069922 0.230386 1.434 0.000 3.6111 0.069098 0.234248 1.447 0.000 3.6667 0.068221 0.238063 1.460 0.000 3.7222 0.067288 0.241827 1.473 0.000 3.7778 0.066299 0.245538 1.499 0.000 3.8333 0.065249 0.249192 1.565 0.000 3.8889 0.064136 0.252787 1.654 0.000 3.9444 0.062957 0.256317 1.761 0.000 4.0000 0.061708 0.259781 1.882 0.000 4.0556 0.060384 0.263173 2.016 0.000 4.1111 0.058981 0.266489 2.162 0.000 4.1667 0.057493 0.269724 2.318 0.000 4.2222 0.055913 0.272875 2.484 0.000 4.2778 0.054232 0.275935 2.659 0.000 4.3333 0.052442 0.278899 2.843 0.000 4.3889 0.050530 0.281760 3.035 0.000 4.4444 0.048482 0.284511 3.236 0.000 4.5000 0.046281 0.287144 3.444 0.000 4.5556 0.043903 0.289650 3.733 0.000 4.6111 0.041317 0.292018 4.251 0.000 4.6667 0.038482 0.294236 4.916 0.000 4.7222 0.035337 0.296288 5.694 0.000 4.7778 0.031792 0.298155 6.560 0.000 4.8333 0.027692 0.299810 7.490 0.000 4.8889 0.022740 0.301216 8.461 0.000 4.9444 0.016171 0.302308 9.450 0.000 5.0000 0.000000 0.302908 10.43 0.000 5.0556 0.000000 0.000000 11.38 0.000 Flow control 6/3/2026 9:26:05 AM Page 13 Flow control 6/3/2026 9:26:05 AM Page 14 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.31 Total Impervious Area:1.06 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.49 Total Impervious Area:0.68 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.423933 5 year 0.542659 10 year 0.624157 25 year 0.730726 50 year 0.81287 100 year 0.897476 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.291398 5 year 0.38184 10 year 0.445049 25 year 0.528881 50 year 0.594306 100 year 0.662351 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.568 0.407 1950 0.573 0.374 1951 0.354 0.253 1952 0.294 0.192 1953 0.318 0.208 1954 0.345 0.237 1955 0.387 0.261 1956 0.382 0.259 1957 0.446 0.314 1958 0.347 0.233 Peak flows are reduced from existing to proposed condition Flow control 6/3/2026 9:26:35 AM Page 15 1959 0.343 0.220 1960 0.366 0.263 1961 0.377 0.262 1962 0.316 0.209 1963 0.365 0.254 1964 0.343 0.235 1965 0.462 0.328 1966 0.297 0.201 1967 0.517 0.372 1968 0.588 0.403 1969 0.420 0.298 1970 0.396 0.272 1971 0.472 0.325 1972 0.513 0.376 1973 0.281 0.180 1974 0.437 0.306 1975 0.472 0.318 1976 0.338 0.237 1977 0.344 0.225 1978 0.423 0.284 1979 0.581 0.378 1980 0.578 0.429 1981 0.440 0.299 1982 0.634 0.450 1983 0.496 0.329 1984 0.320 0.219 1985 0.441 0.301 1986 0.373 0.256 1987 0.573 0.377 1988 0.342 0.219 1989 0.428 0.274 1990 0.837 0.646 1991 0.648 0.484 1992 0.317 0.217 1993 0.269 0.179 1994 0.285 0.183 1995 0.388 0.262 1996 0.436 0.315 1997 0.417 0.296 1998 0.402 0.268 1999 0.864 0.612 2000 0.422 0.292 2001 0.445 0.291 2002 0.559 0.402 2003 0.434 0.313 2004 0.804 0.566 2005 0.369 0.260 2006 0.330 0.237 2007 0.756 0.579 2008 0.636 0.475 2009 0.523 0.336 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.8642 0.6462 2 0.8367 0.6123 3 0.8039 0.5795 Flow control 6/3/2026 9:26:35 AM Page 16 4 0.7561 0.5655 5 0.6481 0.4841 6 0.6364 0.4751 7 0.6342 0.4503 8 0.5882 0.4293 9 0.5812 0.4069 10 0.5783 0.4026 11 0.5734 0.4022 12 0.5728 0.3782 13 0.5684 0.3772 14 0.5587 0.3758 15 0.5232 0.3742 16 0.5165 0.3722 17 0.5132 0.3364 18 0.4959 0.3286 19 0.4723 0.3281 20 0.4722 0.3249 21 0.4622 0.3176 22 0.4456 0.3147 23 0.4449 0.3136 24 0.4407 0.3127 25 0.4402 0.3065 26 0.4373 0.3008 27 0.4359 0.2992 28 0.4342 0.2978 29 0.4276 0.2958 30 0.4232 0.2921 31 0.4221 0.2910 32 0.4202 0.2835 33 0.4171 0.2744 34 0.4024 0.2720 35 0.3958 0.2676 36 0.3884 0.2630 37 0.3868 0.2623 38 0.3819 0.2622 39 0.3770 0.2615 40 0.3735 0.2604 41 0.3686 0.2593 42 0.3660 0.2557 43 0.3650 0.2539 44 0.3541 0.2527 45 0.3466 0.2372 46 0.3453 0.2368 47 0.3443 0.2366 48 0.3433 0.2349 49 0.3426 0.2327 50 0.3419 0.2253 51 0.3383 0.2199 52 0.3298 0.2194 53 0.3203 0.2192 54 0.3180 0.2172 55 0.3173 0.2090 56 0.3162 0.2076 57 0.2975 0.2011 58 0.2943 0.1920 59 0.2853 0.1831 60 0.2808 0.1803 61 0.2690 0.1789 Flow control 6/3/2026 9:26:35 AM Page 17 Flow control 6/3/2026 9:26:35 AM Page 18 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.2120 1736 423 24 Pass 0.2180 1557 379 24 Pass 0.2241 1412 343 24 Pass 0.2302 1278 316 24 Pass 0.2362 1138 290 25 Pass 0.2423 1045 260 24 Pass 0.2484 957 227 23 Pass 0.2545 882 213 24 Pass 0.2605 801 195 24 Pass 0.2666 736 174 23 Pass 0.2727 674 164 24 Pass 0.2787 628 147 23 Pass 0.2848 576 135 23 Pass 0.2909 538 123 22 Pass 0.2969 504 112 22 Pass 0.3030 453 104 22 Pass 0.3091 414 98 23 Pass 0.3152 387 89 22 Pass 0.3212 362 84 23 Pass 0.3273 345 79 22 Pass 0.3334 322 72 22 Pass 0.3394 297 69 23 Pass 0.3455 275 65 23 Pass 0.3516 256 62 24 Pass 0.3576 238 58 24 Pass 0.3637 225 57 25 Pass 0.3698 208 54 25 Pass 0.3758 197 45 22 Pass 0.3819 185 38 20 Pass 0.3880 172 37 21 Pass 0.3941 158 32 20 Pass 0.4001 149 31 20 Pass 0.4062 141 29 20 Pass 0.4123 130 26 20 Pass 0.4183 126 24 19 Pass 0.4244 114 22 19 Pass 0.4305 110 21 19 Pass 0.4365 104 20 19 Pass 0.4426 95 18 18 Pass 0.4487 88 17 19 Pass 0.4548 82 14 17 Pass 0.4608 81 14 17 Pass 0.4669 79 12 15 Pass 0.4730 78 11 14 Pass 0.4790 73 10 13 Pass 0.4851 68 8 11 Pass 0.4912 65 8 12 Pass 0.4972 62 7 11 Pass 0.5033 57 7 12 Pass 0.5094 56 7 12 Pass 0.5155 52 7 13 Pass 0.5215 48 7 14 Pass 0.5276 47 7 14 Pass Flow control 6/3/2026 9:26:35 AM Page 19 0.5337 45 7 15 Pass 0.5397 41 6 14 Pass 0.5458 40 5 12 Pass 0.5519 39 5 12 Pass 0.5579 33 5 15 Pass 0.5640 31 4 12 Pass 0.5701 29 3 10 Pass 0.5762 27 3 11 Pass 0.5822 22 2 9 Pass 0.5883 22 2 9 Pass 0.5944 20 2 10 Pass 0.6004 18 2 11 Pass 0.6065 16 2 12 Pass 0.6126 16 2 12 Pass 0.6186 15 1 6 Pass 0.6247 14 1 7 Pass 0.6308 13 1 7 Pass 0.6368 11 1 9 Pass 0.6429 9 1 11 Pass 0.6490 9 0 0 Pass 0.6551 8 0 0 Pass 0.6611 8 0 0 Pass 0.6672 8 0 0 Pass 0.6733 8 0 0 Pass 0.6793 8 0 0 Pass 0.6854 8 0 0 Pass 0.6915 8 0 0 Pass 0.6975 8 0 0 Pass 0.7036 8 0 0 Pass 0.7097 8 0 0 Pass 0.7158 7 0 0 Pass 0.7218 7 0 0 Pass 0.7279 7 0 0 Pass 0.7340 7 0 0 Pass 0.7400 7 0 0 Pass 0.7461 6 0 0 Pass 0.7522 6 0 0 Pass 0.7582 5 0 0 Pass 0.7643 5 0 0 Pass 0.7704 4 0 0 Pass 0.7765 4 0 0 Pass 0.7825 4 0 0 Pass 0.7886 4 0 0 Pass 0.7947 3 0 0 Pass 0.8007 3 0 0 Pass 0.8068 2 0 0 Pass 0.8129 2 0 0 Pass Flow control 6/3/2026 9:26:35 AM Page 20 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Flow control 6/3/2026 9:26:35 AM Page 21 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:10.57 Total Impervious Area:17.88 Mitigated Landuse Totals for POC #2 Total Pervious Area:9.23 Total Impervious Area:19.56 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 7.502197 5 year 9.759844 10 year 11.328969 25 year 13.400963 50 year 15.011818 100 year 16.682151 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 6.752241 5 year 8.689447 10 year 10.052228 25 year 11.869217 50 year 13.29411 100 year 14.781992 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 10.363 8.990 1950 9.785 8.615 1951 6.441 5.996 1952 5.023 4.799 1953 5.431 5.157 1954 6.113 5.540 1955 6.769 6.296 1956 6.705 6.073 1957 8.026 7.393 1958 6.036 5.457 1959 5.782 5.127 Peak flows are reduced from existing to proposed condition Flow control 6/3/2026 9:27:04 AM Page 22 1960 6.692 6.096 1961 6.732 6.214 1962 5.447 4.998 1963 6.519 5.773 1964 6.059 5.602 1965 8.377 7.391 1966 5.207 4.947 1967 9.355 8.319 1968 10.386 8.877 1969 7.606 6.714 1970 7.009 6.250 1971 8.369 7.382 1972 9.511 8.310 1973 4.739 4.470 1974 7.852 6.798 1975 8.111 7.343 1976 6.069 5.484 1977 5.817 5.322 1978 7.360 6.902 1979 9.902 8.539 1980 10.825 9.331 1981 7.733 7.101 1982 11.431 10.263 1983 8.557 7.787 1984 5.654 5.170 1985 7.766 7.086 1986 6.529 6.323 1987 9.844 8.548 1988 5.768 5.380 1989 7.214 6.179 1990 16.122 14.146 1991 12.187 10.900 1992 5.603 5.223 1993 4.653 4.218 1994 4.813 4.434 1995 6.792 6.147 1996 7.996 7.306 1997 7.554 6.824 1998 6.961 6.261 1999 15.640 13.290 2000 7.510 6.765 2001 7.606 6.700 2002 10.227 9.131 2003 7.950 6.832 2004 14.474 13.118 2005 6.656 6.354 2006 6.023 5.427 2007 14.428 12.298 2008 11.961 12.174 2009 8.840 7.850 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 16.1218 14.1457 2 15.6402 13.2897 3 14.4737 13.1177 4 14.4276 12.2983 Flow control 6/3/2026 9:27:04 AM Page 23 5 12.1868 12.1744 6 11.9610 10.9000 7 11.4313 10.2625 8 10.8247 9.3314 9 10.3855 9.1305 10 10.3629 8.9905 11 10.2268 8.8769 12 9.9019 8.6153 13 9.8437 8.5484 14 9.7851 8.5392 15 9.5106 8.3185 16 9.3549 8.3097 17 8.8402 7.8503 18 8.5566 7.7868 19 8.3765 7.3928 20 8.3688 7.3907 21 8.1115 7.3816 22 8.0259 7.3433 23 7.9963 7.3057 24 7.9499 7.1006 25 7.8522 7.0862 26 7.7660 6.9018 27 7.7329 6.8324 28 7.6061 6.8244 29 7.6057 6.7983 30 7.5537 6.7649 31 7.5101 6.7136 32 7.3599 6.7001 33 7.2141 6.3541 34 7.0087 6.3233 35 6.9610 6.2955 36 6.7918 6.2609 37 6.7690 6.2497 38 6.7324 6.2137 39 6.7051 6.1791 40 6.6920 6.1465 41 6.6559 6.0956 42 6.5294 6.0733 43 6.5192 5.9957 44 6.4411 5.7726 45 6.1129 5.6020 46 6.0686 5.5395 47 6.0595 5.4842 48 6.0361 5.4572 49 6.0227 5.4270 50 5.8171 5.3804 51 5.7818 5.3225 52 5.7683 5.2230 53 5.6540 5.1700 54 5.6030 5.1574 55 5.4470 5.1274 56 5.4308 4.9980 57 5.2067 4.9470 58 5.0233 4.7986 59 4.8135 4.4699 60 4.7394 4.4342 61 4.6531 4.2175 Flow control 6/3/2026 9:27:04 AM Page 24 Flow control 6/3/2026 9:27:04 AM Page 25 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 3.7511 1650 1607 97 Pass 3.8648 1498 1438 95 Pass 3.9786 1333 1287 96 Pass 4.0923 1195 1154 96 Pass 4.2061 1079 1031 95 Pass 4.3198 982 910 92 Pass 4.4336 893 817 91 Pass 4.5473 805 735 91 Pass 4.6611 741 669 90 Pass 4.7748 676 608 89 Pass 4.8885 630 559 88 Pass 5.0023 572 510 89 Pass 5.1160 533 467 87 Pass 5.2298 494 418 84 Pass 5.3435 448 380 84 Pass 5.4573 419 351 83 Pass 5.5710 388 319 82 Pass 5.6848 363 298 82 Pass 5.7985 338 277 81 Pass 5.9122 320 256 80 Pass 6.0260 297 231 77 Pass 6.1397 276 213 77 Pass 6.2535 254 201 79 Pass 6.3672 230 187 81 Pass 6.4810 219 176 80 Pass 6.5947 205 171 83 Pass 6.7085 191 158 82 Pass 6.8222 177 147 83 Pass 6.9359 168 132 78 Pass 7.0497 157 126 80 Pass 7.1634 148 116 78 Pass 7.2772 136 109 80 Pass 7.3909 130 103 79 Pass 7.5047 119 95 79 Pass 7.6184 108 89 82 Pass 7.7322 106 85 80 Pass 7.8459 101 81 80 Pass 7.9597 97 73 75 Pass 8.0734 88 69 78 Pass 8.1871 83 69 83 Pass 8.3009 82 67 81 Pass 8.4146 77 63 81 Pass 8.5284 76 62 81 Pass 8.6421 71 55 77 Pass 8.7559 66 52 78 Pass 8.8696 64 50 78 Pass 8.9834 61 46 75 Pass 9.0971 59 44 74 Pass 9.2108 58 41 70 Pass 9.3246 55 40 72 Pass 9.4383 50 38 76 Pass 9.5521 47 36 76 Pass 9.6658 42 33 78 Pass Flow control 6/3/2026 9:27:04 AM Page 26 9.7796 40 30 75 Pass 9.8933 37 29 78 Pass 10.0071 34 26 76 Pass 10.1208 31 26 83 Pass 10.2345 30 22 73 Pass 10.3483 30 16 53 Pass 10.4620 26 14 53 Pass 10.5758 25 14 56 Pass 10.6895 22 13 59 Pass 10.8033 22 12 54 Pass 10.9170 21 11 52 Pass 11.0308 20 11 55 Pass 11.1445 20 11 55 Pass 11.2582 17 9 52 Pass 11.3720 15 9 60 Pass 11.4857 14 9 64 Pass 11.5995 13 9 69 Pass 11.7132 13 8 61 Pass 11.8270 12 8 66 Pass 11.9407 11 8 72 Pass 12.0545 10 8 80 Pass 12.1682 9 8 88 Pass 12.2819 8 6 75 Pass 12.3957 8 5 62 Pass 12.5094 8 5 62 Pass 12.6232 8 4 50 Pass 12.7369 7 3 42 Pass 12.8507 7 3 42 Pass 12.9644 7 3 42 Pass 13.0782 7 3 42 Pass 13.1919 7 2 28 Pass 13.3056 7 1 14 Pass 13.4194 7 1 14 Pass 13.5331 7 1 14 Pass 13.6469 7 1 14 Pass 13.7606 6 1 16 Pass 13.8744 5 1 20 Pass 13.9881 5 1 20 Pass 14.1019 5 1 20 Pass 14.2156 5 0 0 Pass 14.3294 5 0 0 Pass 14.4431 3 0 0 Pass 14.5568 2 0 0 Pass 14.6706 2 0 0 Pass 14.7843 2 0 0 Pass 14.8981 2 0 0 Pass 15.0118 2 0 0 Pass Flow control 6/3/2026 9:27:04 AM Page 27 Water Quality Water Quality BMP Flow and Volume for POC #2 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. Flow control 6/3/2026 9:27:04 AM Page 28 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:2.08 Total Impervious Area:4.89 Mitigated Landuse Totals for POC #3 Total Pervious Area:1.15 Total Impervious Area:5.69 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 1.997582 5 year 2.574396 10 year 2.972409 25 year 3.494998 50 year 3.899261 100 year 4.316815 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 2.242921 5 year 2.859032 10 year 3.280586 25 year 3.830426 50 year 4.253301 100 year 4.68809 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 2.717 2.977 1950 2.657 3.063 1951 1.691 1.856 1952 1.365 1.574 1953 1.475 1.700 1954 1.628 1.826 1955 1.814 2.053 1956 1.794 2.025 1957 2.118 2.343 1958 1.622 1.842 1959 1.581 1.838 TDA 3 does not require flow control due to the direct discharge exemption. Flow control 6/3/2026 9:27:33 AM Page 29 1960 1.752 1.915 1961 1.785 1.988 1962 1.472 1.686 1963 1.728 1.924 1964 1.616 1.822 1965 2.203 2.425 1966 1.395 1.579 1967 2.431 2.735 1968 2.770 3.113 1969 2.002 2.206 1970 1.866 2.093 1971 2.228 2.497 1972 2.471 2.672 1973 1.296 1.507 1974 2.075 2.301 1975 2.179 2.534 1976 1.605 1.781 1977 1.589 1.847 1978 1.979 2.267 1979 2.693 3.110 1980 2.798 3.002 1981 2.068 2.333 1982 3.007 3.340 1983 2.311 2.643 1984 1.508 1.695 1985 2.073 2.333 1986 1.740 1.991 1987 2.666 3.062 1988 1.577 1.835 1989 1.973 2.295 1990 4.104 4.298 1991 3.143 3.358 1992 1.494 1.679 1993 1.255 1.433 1994 1.316 1.532 1995 1.821 2.062 1996 2.089 2.278 1997 1.987 2.189 1998 1.877 2.143 1999 4.116 4.537 2000 1.995 2.228 2001 2.065 2.378 2002 2.675 2.921 2003 2.079 2.270 2004 3.820 4.227 2005 1.754 1.936 2006 1.577 1.726 2007 3.662 3.969 2008 3.085 3.298 2009 2.415 2.807 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #3 Rank Predeveloped Mitigated 1 4.1161 4.5367 2 4.1043 4.2982 3 3.8197 4.2273 4 3.6621 3.9688 Flow control 6/3/2026 9:27:33 AM Page 30 5 3.1426 3.3584 6 3.0851 3.3402 7 3.0067 3.2983 8 2.7981 3.1130 9 2.7700 3.1103 10 2.7165 3.0628 11 2.6931 3.0616 12 2.6750 3.0016 13 2.6662 2.9766 14 2.6574 2.9215 15 2.4713 2.8072 16 2.4307 2.7348 17 2.4155 2.6724 18 2.3110 2.6433 19 2.2278 2.5342 20 2.2027 2.4968 21 2.1789 2.4250 22 2.1175 2.3781 23 2.0892 2.3426 24 2.0791 2.3335 25 2.0752 2.3333 26 2.0734 2.3014 27 2.0682 2.2952 28 2.0647 2.2778 29 2.0016 2.2703 30 1.9947 2.2666 31 1.9872 2.2282 32 1.9793 2.2060 33 1.9728 2.1890 34 1.8774 2.1431 35 1.8663 2.0925 36 1.8211 2.0620 37 1.8142 2.0529 38 1.7939 2.0248 39 1.7846 1.9911 40 1.7537 1.9878 41 1.7515 1.9363 42 1.7403 1.9244 43 1.7279 1.9149 44 1.6905 1.8558 45 1.6281 1.8470 46 1.6221 1.8425 47 1.6164 1.8385 48 1.6048 1.8353 49 1.5894 1.8261 50 1.5807 1.8220 51 1.5774 1.7813 52 1.5774 1.7261 53 1.5082 1.7004 54 1.4944 1.6953 55 1.4751 1.6864 56 1.4725 1.6793 57 1.3953 1.5786 58 1.3648 1.5740 59 1.3164 1.5316 60 1.2958 1.5073 61 1.2550 1.4327 Flow control 6/3/2026 9:27:33 AM Page 31 Flow control 6/3/2026 9:27:33 AM Page 32 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.9988 1694 2594 153 Fail 1.0281 1534 2366 154 Fail 1.0574 1380 2162 156 Fail 1.0867 1234 1968 159 Fail 1.1160 1109 1770 159 Fail 1.1453 1014 1618 159 Fail 1.1746 932 1485 159 Fail 1.2039 851 1340 157 Fail 1.2332 763 1221 160 Fail 1.2625 706 1103 156 Fail 1.2918 656 1025 156 Fail 1.3211 600 938 156 Fail 1.3504 555 870 156 Fail 1.3797 521 804 154 Fail 1.4090 477 743 155 Fail 1.4383 438 678 154 Fail 1.4676 404 636 157 Fail 1.4969 377 594 157 Fail 1.5261 356 557 156 Fail 1.5554 337 520 154 Fail 1.5847 309 479 155 Fail 1.6140 287 441 153 Fail 1.6433 266 414 155 Fail 1.6726 248 385 155 Fail 1.7019 232 363 156 Fail 1.7312 214 344 160 Fail 1.7605 198 321 162 Fail 1.7898 191 300 157 Fail 1.8191 177 279 157 Fail 1.8484 165 260 157 Fail 1.8777 153 246 160 Fail 1.9070 143 228 159 Fail 1.9363 133 216 162 Fail 1.9656 129 203 157 Fail 1.9949 119 191 160 Fail 2.0242 112 178 158 Fail 2.0535 105 166 158 Fail 2.0828 97 160 164 Fail 2.1121 91 146 160 Fail 2.1414 86 142 165 Fail 2.1707 82 132 160 Fail 2.2000 79 124 156 Fail 2.2293 76 117 153 Fail 2.2586 76 112 147 Fail 2.2879 73 105 143 Fail 2.3172 66 100 151 Fail 2.3465 65 93 143 Fail 2.3758 60 86 143 Fail 2.4051 58 82 141 Fail 2.4344 53 80 150 Fail 2.4637 51 79 154 Fail 2.4930 49 76 155 Fail 2.5223 47 71 151 Fail 2.5516 42 67 159 Fail TDA 3 is flow control exempt. This calculation is included for reference only. Flow control 6/3/2026 9:27:33 AM Page 33 2.5809 41 62 151 Fail 2.6102 38 61 160 Fail 2.6395 36 59 163 Fail 2.6688 33 56 169 Fail 2.6981 29 52 179 Fail 2.7274 26 51 196 Fail 2.7567 26 48 184 Fail 2.7859 23 47 204 Fail 2.8152 21 43 204 Fail 2.8445 21 41 195 Fail 2.8738 19 40 210 Fail 2.9031 17 37 217 Fail 2.9324 17 33 194 Fail 2.9617 15 32 213 Fail 2.9910 14 29 207 Fail 3.0203 13 27 207 Fail 3.0496 12 25 208 Fail 3.0789 12 23 191 Fail 3.1082 9 21 233 Fail 3.1375 9 17 188 Fail 3.1668 8 16 200 Fail 3.1961 8 16 200 Fail 3.2254 8 15 187 Fail 3.2547 8 13 162 Fail 3.2840 8 12 150 Fail 3.3133 8 11 137 Fail 3.3426 8 9 112 Fail 3.3719 7 8 114 Fail 3.4012 7 8 114 Fail 3.4305 7 8 114 Fail 3.4598 7 8 114 Fail 3.4891 7 8 114 Fail 3.5184 7 8 114 Fail 3.5477 7 8 114 Fail 3.5770 7 8 114 Fail 3.6063 6 8 133 Fail 3.6356 6 8 133 Fail 3.6649 4 8 200 Fail 3.6942 4 8 200 Fail 3.7235 4 8 200 Fail 3.7528 4 7 175 Fail 3.7821 3 7 233 Fail 3.8114 3 7 233 Fail 3.8407 2 6 300 Fail 3.8700 2 6 300 Fail 3.8993 2 6 300 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. Flow control 6/3/2026 9:27:33 AM Page 34 Water Quality Water Quality BMP Flow and Volume for POC #3 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. Flow control 6/3/2026 9:27:33 AM Page 35 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. Flow control 6/3/2026 9:27:33 AM Page 36 Appendix Predeveloped Schematic Flow control 6/3/2026 9:27:35 AM Page 37 Mitigated Schematic Flow control 6/3/2026 9:27:37 AM Page 38 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 Flow control.wdm MESSU 25 PreFlow control.MES 27 PreFlow control.L61 28 PreFlow control.L62 30 POCFlow control1.dat 31 POCFlow control2.dat 32 POCFlow control3.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 COPY 501 COPY 502 COPY 503 DISPLY 1 DISPLY 2 DISPLY 3 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 TDA 1 MAX 1 2 30 9 2 TDA 2 MAX 1 2 31 9 3 Basin 3 MAX 1 2 32 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 503 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY Flow control 6/3/2026 9:27:37 AM Page 39 <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 Flow control 6/3/2026 9:27:37 AM Page 40 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** TDA 1*** PERLND 16 0.31 COPY 501 12 PERLND 16 0.31 COPY 501 13 IMPLND 1 1.06 COPY 501 15 TDA 2*** PERLND 16 10.57 COPY 502 12 PERLND 16 10.57 COPY 502 13 IMPLND 1 17.88 COPY 502 15 Basin 3*** PERLND 16 2.08 COPY 503 12 PERLND 16 2.08 COPY 503 13 IMPLND 1 4.89 COPY 503 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 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 COPY 503 OUTPUT MEAN 1 1 48.4 DISPLY 3 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 Flow control 6/3/2026 9:27:37 AM Page 41 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 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 502 FLOW ENGL REPL COPY 503 OUTPUT MEAN 1 1 48.4 WDM 503 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 Flow control 6/3/2026 9:27:37 AM Page 42 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 Flow control.wdm MESSU 25 MitFlow control.MES 27 MitFlow control.L61 28 MitFlow control.L62 30 POCFlow control1.dat 32 POCFlow control3.dat 31 POCFlow control2.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 RCHRES 1 COPY 501 COPY 503 COPY 2 COPY 502 COPY 602 DISPLY 1 DISPLY 3 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 3 Basin 3 MAX 1 2 32 9 2 Tank 2B MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 503 1 1 2 1 1 502 1 1 602 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 *** Flow control 6/3/2026 9:27:37 AM Page 43 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 Flow control 6/3/2026 9:27:37 AM Page 44 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 2B*** PERLND 16 1.06 RCHRES 1 2 PERLND 16 1.06 RCHRES 1 3 IMPLND 1 5.61 RCHRES 1 5 Basin 1*** PERLND 16 0.49 COPY 501 12 PERLND 16 0.49 COPY 501 13 IMPLND 1 0.68 COPY 501 15 Basin 2A*** PERLND 16 8.17 COPY 502 12 PERLND 16 8.17 COPY 602 12 PERLND 16 8.17 COPY 502 13 PERLND 16 8.17 COPY 602 13 IMPLND 1 13.95 COPY 502 15 IMPLND 1 13.95 COPY 602 15 Basin 3*** PERLND 16 1.15 COPY 503 12 PERLND 16 1.15 COPY 503 13 IMPLND 1 5.69 COPY 503 15 ******Routing****** PERLND 16 1.06 COPY 2 12 IMPLND 1 5.61 COPY 2 15 PERLND 16 1.06 COPY 2 13 RCHRES 1 1 COPY 502 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 COPY 503 OUTPUT MEAN 1 1 48.4 DISPLY 3 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO Flow control 6/3/2026 9:27:37 AM Page 45 RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Tank 2B 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.13 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 91 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.000000 0.000000 0.000000 0.055556 0.016171 0.000600 0.000000 0.111111 0.022740 0.001692 0.000000 0.166667 0.027692 0.003098 0.000000 0.222222 0.031792 0.004753 0.000000 0.277778 0.035337 0.006620 0.000000 0.333333 0.038482 0.008672 0.000000 0.388889 0.041317 0.010890 0.000000 0.444444 0.043903 0.013259 0.000000 0.500000 0.046281 0.015765 0.000000 0.555556 0.048482 0.018398 0.193485 0.611111 0.050530 0.021149 0.273629 0.666667 0.052442 0.024010 0.335126 0.722222 0.054232 0.026973 0.386970 0.777778 0.055913 0.030033 0.432646 0.833333 0.057493 0.033184 0.473940 0.888889 0.058981 0.036420 0.511914 0.944444 0.060384 0.039736 0.547259 1.000000 0.061708 0.043128 0.580456 1.055556 0.062957 0.046591 0.611854 1.111111 0.064136 0.050122 0.641718 1.166667 0.065249 0.053716 0.670253 Flow control 6/3/2026 9:27:37 AM Page 46 1.222222 0.066299 0.057370 0.697621 1.277778 0.067288 0.061081 0.723955 1.333333 0.068221 0.064846 0.749365 1.388889 0.069098 0.068660 0.773941 1.444444 0.069922 0.072522 0.797760 1.500000 0.070695 0.076429 0.820888 1.555556 0.071419 0.080376 0.843383 1.611111 0.072095 0.084363 0.865292 1.666667 0.072724 0.088386 0.886661 1.722222 0.073307 0.092443 0.907526 1.777778 0.073846 0.096530 0.927923 1.833333 0.074342 0.100647 0.947880 1.888889 0.074795 0.104790 0.967426 1.944444 0.075206 0.108957 0.986585 2.000000 0.075577 0.113145 1.005379 2.055556 0.075906 0.117353 1.023828 2.111111 0.076196 0.121579 1.041950 2.166667 0.076446 0.125819 1.059762 2.222222 0.076657 0.130072 1.077280 2.277778 0.076830 0.134336 1.094518 2.333333 0.076963 0.138608 1.111488 2.388889 0.077059 0.142886 1.128203 2.444444 0.077116 0.147169 1.144674 2.500000 0.077135 0.151454 1.160911 2.555556 0.077116 0.155739 1.176925 2.611111 0.077059 0.160022 1.192723 2.666667 0.076963 0.164300 1.208315 2.722222 0.076830 0.168573 1.223708 2.777778 0.076657 0.172836 1.238910 2.833333 0.076446 0.177089 1.253928 2.888889 0.076196 0.181330 1.268768 2.944444 0.075906 0.185555 1.283436 3.000000 0.075577 0.189763 1.297938 3.055556 0.075206 0.193952 1.312281 3.111111 0.074795 0.198119 1.326468 3.166667 0.074342 0.202261 1.340505 3.222222 0.073846 0.206378 1.354397 3.277778 0.073307 0.210466 1.368147 3.333333 0.072724 0.214522 1.381761 3.388889 0.072095 0.218545 1.395242 3.444444 0.071419 0.222532 1.408594 3.500000 0.070695 0.226480 1.421820 3.555556 0.069922 0.230386 1.434925 3.611111 0.069098 0.234248 1.447911 3.666667 0.068221 0.238063 1.460782 3.722222 0.067288 0.241827 1.473540 3.777778 0.066299 0.245538 1.499035 3.833333 0.065249 0.249192 1.565484 3.888889 0.064136 0.252787 1.654799 3.944444 0.062957 0.256317 1.761429 4.000000 0.061708 0.259781 1.882603 4.055556 0.060384 0.263173 2.016567 4.111111 0.058981 0.266489 2.162081 4.166667 0.057493 0.269724 2.318208 4.222222 0.055913 0.272875 2.484207 4.277778 0.054232 0.275935 2.659473 4.333333 0.052442 0.278899 2.843500 4.388889 0.050530 0.281760 3.035859 4.444444 0.048482 0.284511 3.236174 4.500000 0.046281 0.287144 3.444120 4.555556 0.043903 0.289650 3.733278 4.611111 0.041317 0.292018 4.251535 4.666667 0.038482 0.294236 4.916466 4.722222 0.035337 0.296288 5.694370 4.777778 0.031792 0.298155 6.560098 4.833333 0.027692 0.299810 7.490370 4.888889 0.022740 0.301216 8.461745 4.944444 0.016171 0.302308 9.450166 5.000000 0.001000 0.302908 10.43124 END FTABLE 1 Flow control 6/3/2026 9:27:37 AM Page 47 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 COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL COPY 2 OUTPUT MEAN 1 1 48.4 WDM 702 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 802 FLOW ENGL REPL COPY 602 OUTPUT MEAN 1 1 48.4 WDM 902 FLOW ENGL REPL RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1001 STAG ENGL REPL COPY 3 OUTPUT MEAN 1 1 48.4 WDM 703 FLOW ENGL REPL COPY 503 OUTPUT MEAN 1 1 48.4 WDM 803 FLOW ENGL REPL COPY 603 OUTPUT MEAN 1 1 48.4 WDM 903 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 2 PERLND PWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 2 MASS-LINK 3 PERLND PWATER IFWO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 3 MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 16 RCHRES ROFLOW COPY INPUT MEAN END MASS-LINK 16 END MASS-LINK END RUN Flow control 6/3/2026 9:27:37 AM Page 48 Predeveloped HSPF Message File Flow control 6/3/2026 9:27:37 AM Page 49 Mitigated HSPF Message File Flow control 6/3/2026 9:27:37 AM Page 50 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. 2005-2026; 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 Technical Information Report New Renton High School Project No. 2230388.10 Appendix D Water Quality Calculations WWHM2012 PROJECT REPORT APPENDIX D WATER QUALITY CALCULATIONS Treatment 3/31/2026 1:49:26 PM Page 2 General Model Information WWHM2012 Project Name:Treatment Site Name: Site Address: City: Report Date:3/31/2026 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2025/05/13 Version:4.3.2 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Low Flow Threshold for POC3:50 Percent of the 2 Year High Flow Threshold for POC3:50 Year Low Flow Threshold for POC4:50 Percent of the 2 Year High Flow Threshold for POC4:50 Year Low Flow Threshold for POC5:50 Percent of the 2 Year High Flow Threshold for POC5:50 Year Low Flow Threshold for POC6:50 Percent of the 2 Year High Flow Threshold for POC6:50 Year Low Flow Threshold for POC7:50 Percent of the 2 Year High Flow Threshold for POC7:50 Year Low Flow Threshold for POC8:50 Percent of the 2 Year High Flow Threshold for POC8:50 Year Low Flow Threshold for POC9:50 Percent of the 2 Year High Flow Threshold for POC9:50 Year Treatment 3/31/2026 1:49:27 PM Page 3 Low Flow Threshold for POC10:50 Percent of the 2 Year High Flow Threshold for POC10:50 Year Treatment 3/31/2026 1:49:27 PM Page 4 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.59 Pervious Total 0.59 Impervious Land Use acre ROADS FLAT 1.73 Impervious Total 1.73 Basin Total 2.32 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 Treatment 3/31/2026 1:49:27 PM Page 5 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 1.91 Impervious Total 1.91 Basin Total 1.91 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Treatment 3/31/2026 1:49:27 PM Page 6 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 6.2 Impervious Total 6.2 Basin Total 7.77 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 3 POC 3 Treatment 3/31/2026 1:49:27 PM Page 7 Basin 4 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 2.72 Impervious Total 2.72 Basin Total 2.72 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 4 POC 4 Treatment 3/31/2026 1:49:27 PM Page 8 Basin 5 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 0.25 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 5 POC 5 Treatment 3/31/2026 1:49:27 PM Page 9 Basin 6 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.24 Pervious Total 0.24 Impervious Land Use acre ROADS FLAT 1.85 Impervious Total 1.85 Basin Total 2.09 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 6 POC 6 Treatment 3/31/2026 1:49:27 PM Page 10 Basin 7 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.24 Pervious Total 0.24 Impervious Land Use acre ROADS FLAT 0.58 Impervious Total 0.58 Basin Total 0.82 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 7 POC 7 Treatment 3/31/2026 1:49:27 PM Page 11 Basin 8 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.33 Pervious Total 0.33 Impervious Land Use acre ROADS FLAT 1.02 Impervious Total 1.02 Basin Total 1.35 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 8 POC 8 Treatment 3/31/2026 1:49:27 PM Page 12 Basin 9 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 1.82 Pervious Total 1.82 Impervious Land Use acre ROADS FLAT 1.91 Impervious Total 1.91 Basin Total 3.73 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 9 POC 9 Treatment 3/31/2026 1:49:27 PM Page 13 Basin 10 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 0.25 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 10 POC 10 Treatment 3/31/2026 1:49:27 PM Page 14 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.59 Pervious Total 0.59 Impervious Land Use acre ROADS FLAT 1.73 Impervious Total 1.73 Basin Total 2.32 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 Treatment 3/31/2026 1:49:27 PM Page 15 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 1.91 Impervious Total 1.91 Basin Total 1.91 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Treatment 3/31/2026 1:49:27 PM Page 16 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.57 Pervious Total 1.57 Impervious Land Use acre ROADS FLAT 6.2 Impervious Total 6.2 Basin Total 7.77 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 3 POC 3 Treatment 3/31/2026 1:49:27 PM Page 17 Basin 4 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 2.72 Impervious Total 2.72 Basin Total 2.72 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 4 POC 4 Treatment 3/31/2026 1:49:27 PM Page 18 Basin 5 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 0.25 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 5 POC 5 Treatment 3/31/2026 1:49:27 PM Page 19 Basin 6 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.24 Pervious Total 0.24 Impervious Land Use acre ROADS FLAT 1.85 Impervious Total 1.85 Basin Total 2.09 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 6 POC 6 Treatment 3/31/2026 1:49:27 PM Page 20 Basin 7 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.24 Pervious Total 0.24 Impervious Land Use acre ROADS FLAT 0.58 Impervious Total 0.58 Basin Total 0.82 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 7 POC 7 Treatment 3/31/2026 1:49:27 PM Page 21 Basin 8 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.33 Pervious Total 0.33 Impervious Land Use acre ROADS FLAT 1.02 Impervious Total 1.02 Basin Total 1.35 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 8 POC 8 Treatment 3/31/2026 1:49:27 PM Page 22 Basin 9 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 1.82 Pervious Total 1.82 Impervious Land Use acre ROADS FLAT 1.91 Impervious Total 1.91 Basin Total 3.73 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 9 POC 9 Treatment 3/31/2026 1:49:27 PM Page 23 Basin 10 Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.25 Impervious Total 0.25 Basin Total 0.25 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 10 POC 10 Treatment 3/31/2026 1:49:27 PM Page 24 Routing Elements Predeveloped Routing Treatment 3/31/2026 1:49:27 PM Page 25 Mitigated Routing Treatment 3/31/2026 1:49:27 PM Page 26 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.59 Total Impervious Area:1.73 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.59 Total Impervious Area:1.73 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.697268 5 year 0.89458 10 year 1.030259 25 year 1.207922 50 year 1.34503 100 year 1.486383 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.697268 5 year 0.89458 10 year 1.030259 25 year 1.207922 50 year 1.34503 100 year 1.486383 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.940 0.940 1950 0.937 0.937 1951 0.585 0.585 1952 0.481 0.481 1953 0.520 0.520 1954 0.568 0.568 1955 0.635 0.635 1956 0.627 0.627 1957 0.735 0.735 1958 0.569 0.569 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:50:02 PM Page 32 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.2316 acre-feet On-line facility target flow:0.2772 cfs. Adjusted for 15 min:0.2772 cfs. Off-line facility target flow:0.1559 cfs. Adjusted for 15 min:0.1559 cfs. Design flowrate Treatment 3/31/2026 1:50:02 PM Page 33 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0 Total Impervious Area:1.91 Mitigated Landuse Totals for POC #2 Total Pervious Area:0 Total Impervious Area:1.91 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.728215 5 year 0.919821 10 year 1.050003 25 year 1.218869 50 year 1.348114 100 year 1.480498 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.728215 5 year 0.919821 10 year 1.050003 25 year 1.218869 50 year 1.348114 100 year 1.480498 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.943 0.943 1950 1.019 1.019 1951 0.589 0.589 1952 0.524 0.524 1953 0.566 0.566 1954 0.592 0.592 1955 0.671 0.671 1956 0.661 0.661 1957 0.749 0.749 1958 0.605 0.605 1959 0.617 0.617 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:50:33 PM Page 39 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0.2347 acre-feet On-line facility target flow:0.3103 cfs. Adjusted for 15 min:0.3103 cfs. Off-line facility target flow:0.1753 cfs. Adjusted for 15 min:0.1753 cfs. Design flowrate Treatment 3/31/2026 1:50:33 PM Page 40 POC 3 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #3 Total Pervious Area:1.57 Total Impervious Area:6.2 Mitigated Landuse Totals for POC #3 Total Pervious Area:1.57 Total Impervious Area:6.2 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 2.464104 5 year 3.148455 10 year 3.617559 25 year 4.230299 50 year 4.702144 100 year 5.187765 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 2.464104 5 year 3.148455 10 year 3.617559 25 year 4.230299 50 year 4.702144 100 year 5.187765 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 3.289 3.289 1950 3.345 3.345 1951 2.050 2.050 1952 1.719 1.719 1953 1.857 1.857 1954 2.007 2.007 1955 2.251 2.251 1956 2.222 2.222 1957 2.583 2.583 1958 2.019 2.019 1959 2.003 2.003 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:51:06 PM Page 46 Water Quality Water Quality BMP Flow and Volume for POC #3 On-line facility volume:0.8094 acre-feet On-line facility target flow:0.9956 cfs. Adjusted for 15 min:0.9956 cfs. Off-line facility target flow:0.561 cfs. Adjusted for 15 min:0.561 cfs. Design flowrate Treatment 3/31/2026 1:51:06 PM Page 47 POC 4 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #4 Total Pervious Area:0 Total Impervious Area:2.72 Mitigated Landuse Totals for POC #4 Total Pervious Area:0 Total Impervious Area:2.72 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 1.03704 5 year 1.309901 10 year 1.495292 25 year 1.73577 50 year 1.919826 100 year 2.108352 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 1.03704 5 year 1.309901 10 year 1.495292 25 year 1.73577 50 year 1.919826 100 year 2.108352 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 1.343 1.343 1950 1.451 1.451 1951 0.839 0.839 1952 0.746 0.746 1953 0.806 0.806 1954 0.843 0.843 1955 0.956 0.956 1956 0.941 0.941 1957 1.067 1.067 1958 0.861 0.861 1959 0.878 0.878 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:51:36 PM Page 53 Water Quality Water Quality BMP Flow and Volume for POC #4 On-line facility volume:0.3345 acre-feet On-line facility target flow:0.4419 cfs. Adjusted for 15 min:0.4419 cfs. Off-line facility target flow:0.2497 cfs. Adjusted for 15 min:0.2497 cfs. Design flowrate Treatment 3/31/2026 1:51:36 PM Page 54 POC 5 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #5 Total Pervious Area:0 Total Impervious Area:0.25 Mitigated Landuse Totals for POC #5 Total Pervious Area:0 Total Impervious Area:0.25 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.095316 5 year 0.120395 10 year 0.137435 25 year 0.159538 50 year 0.176455 100 year 0.193782 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 0.095316 5 year 0.120395 10 year 0.137435 25 year 0.159538 50 year 0.176455 100 year 0.193782 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.123 0.123 1950 0.133 0.133 1951 0.077 0.077 1952 0.069 0.069 1953 0.074 0.074 1954 0.078 0.078 1955 0.088 0.088 1956 0.086 0.086 1957 0.098 0.098 1958 0.079 0.079 1959 0.081 0.081 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:52:07 PM Page 60 Water Quality Water Quality BMP Flow and Volume for POC #5 On-line facility volume:0.0307 acre-feet On-line facility target flow:0.0406 cfs. Adjusted for 15 min:0.0406 cfs. Off-line facility target flow:0.0229 cfs. Adjusted for 15 min:0.0229 cfs. Design flowrate Treatment 3/31/2026 1:52:07 PM Page 61 POC 6 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #6 Total Pervious Area:0.24 Total Impervious Area:1.85 Mitigated Landuse Totals for POC #6 Total Pervious Area:0.24 Total Impervious Area:1.85 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 0.723697 5 year 0.920512 10 year 1.054954 25 year 1.230082 50 year 1.364617 100 year 1.50282 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 0.720743 5 year 0.915643 10 year 1.048653 25 year 1.221787 50 year 1.354706 100 year 1.491179 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 0.958 0.948 1950 0.995 0.993 1951 0.595 0.592 1952 0.511 0.510 1953 0.552 0.551 1954 0.590 0.587 1955 0.665 0.661 1956 0.654 0.652 1957 0.754 0.749 1958 0.596 0.594 1959 0.598 0.598 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:52:40 PM Page 67 Water Quality Water Quality BMP Flow and Volume for POC #6 On-line facility volume:0.2356 acre-feet On-line facility target flow:0.298 cfs. Adjusted for 15 min:0.298 cfs. Off-line facility target flow:0.1684 cfs. Adjusted for 15 min:0.1684 cfs. Design flowrate Treatment 3/31/2026 1:52:40 PM Page 68 POC 7 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #7 Total Pervious Area:0.24 Total Impervious Area:0.58 Mitigated Landuse Totals for POC #7 Total Pervious Area:0.24 Total Impervious Area:0.58 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #7 Return Period Flow(cfs) 2 year 0.239401 5 year 0.309497 10 year 0.357982 25 year 0.421762 50 year 0.471183 100 year 0.522295 Flow Frequency Return Periods for Mitigated. POC #7 Return Period Flow(cfs) 2 year 0.236498 5 year 0.304595 10 year 0.351561 25 year 0.413203 50 year 0.460872 100 year 0.510096 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #7 Year Predeveloped Mitigated 1949 0.331 0.321 1950 0.317 0.315 1951 0.203 0.200 1952 0.162 0.162 1953 0.175 0.175 1954 0.196 0.193 1955 0.219 0.215 1956 0.214 0.212 1957 0.255 0.251 1958 0.194 0.192 1959 0.188 0.187 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:53:14 PM Page 74 Water Quality Water Quality BMP Flow and Volume for POC #7 On-line facility volume:0.0788 acre-feet On-line facility target flow:0.0927 cfs. Adjusted for 15 min:0.0927 cfs. Off-line facility target flow:0.0521 cfs. Adjusted for 15 min:0.0521 cfs. Design flowrate Treatment 3/31/2026 1:53:14 PM Page 75 POC 8 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #8 Total Pervious Area:0.33 Total Impervious Area:1.02 Mitigated Landuse Totals for POC #8 Total Pervious Area:0.33 Total Impervious Area:1.02 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #8 Return Period Flow(cfs) 2 year 0.414012 5 year 0.53236 10 year 0.613881 25 year 0.720773 50 year 0.803363 100 year 0.888588 Flow Frequency Return Periods for Mitigated. POC #8 Return Period Flow(cfs) 2 year 0.409965 5 year 0.525543 10 year 0.604968 25 year 0.708919 50 year 0.789106 100 year 0.871747 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #8 Year Predeveloped Mitigated 1949 0.565 0.552 1950 0.554 0.552 1951 0.348 0.344 1952 0.284 0.284 1953 0.307 0.306 1954 0.338 0.334 1955 0.379 0.374 1956 0.372 0.369 1957 0.438 0.432 1958 0.338 0.335 1959 0.330 0.330 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:53:47 PM Page 81 Water Quality Water Quality BMP Flow and Volume for POC #8 On-line facility volume:0.136 acre-feet On-line facility target flow:0.1635 cfs. Adjusted for 15 min:0.1635 cfs. Off-line facility target flow:0.092 cfs. Adjusted for 15 min:0.092 cfs. Design flowrate Treatment 3/31/2026 1:53:47 PM Page 82 POC 9 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #9 Total Pervious Area:1.82 Total Impervious Area:1.91 Mitigated Landuse Totals for POC #9 Total Pervious Area:1.82 Total Impervious Area:1.91 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #9 Return Period Flow(cfs) 2 year 0.873151 5 year 1.168337 10 year 1.377981 25 year 1.659562 50 year 1.881764 100 year 2.114882 Flow Frequency Return Periods for Mitigated. POC #9 Return Period Flow(cfs) 2 year 0.873151 5 year 1.168337 10 year 1.377981 25 year 1.659562 50 year 1.881764 100 year 2.114882 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #9 Year Predeveloped Mitigated 1949 1.280 1.280 1950 1.162 1.162 1951 0.775 0.775 1952 0.546 0.546 1953 0.592 0.592 1954 0.715 0.715 1955 0.782 0.782 1956 0.766 0.766 1957 0.960 0.960 1958 0.686 0.686 1959 0.618 0.618 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:54:22 PM Page 88 Water Quality Water Quality BMP Flow and Volume for POC #9 On-line facility volume:0.2906 acre-feet On-line facility target flow:0.3091 cfs. Adjusted for 15 min:0.3091 cfs. Off-line facility target flow:0.1718 cfs. Adjusted for 15 min:0.1718 cfs. Design flowrate Treatment 3/31/2026 1:54:22 PM Page 89 POC 10 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #10 Total Pervious Area:0 Total Impervious Area:0.25 Mitigated Landuse Totals for POC #10 Total Pervious Area:0 Total Impervious Area:0.25 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #10 Return Period Flow(cfs) 2 year 0.095316 5 year 0.120395 10 year 0.137435 25 year 0.159538 50 year 0.176455 100 year 0.193782 Flow Frequency Return Periods for Mitigated. POC #10 Return Period Flow(cfs) 2 year 0.095316 5 year 0.120395 10 year 0.137435 25 year 0.159538 50 year 0.176455 100 year 0.193782 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #10 Year Predeveloped Mitigated 1949 0.123 0.123 1950 0.133 0.133 1951 0.077 0.077 1952 0.069 0.069 1953 0.074 0.074 1954 0.078 0.078 1955 0.088 0.088 1956 0.086 0.086 1957 0.098 0.098 1958 0.079 0.079 1959 0.081 0.081 This calculation is for water quality only. Irrelevant pages from the WWHM report have been deleted. Treatment 3/31/2026 1:54:51 PM Page 95 Water Quality Water Quality BMP Flow and Volume for POC #10 On-line facility volume:0.0307 acre-feet On-line facility target flow:0.0406 cfs. Adjusted for 15 min:0.0406 cfs. Off-line facility target flow:0.0229 cfs. Adjusted for 15 min:0.0229 cfs. Design flowrate Treatment 3/31/2026 1:54:51 PM Page 96 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. Treatment 3/31/2026 1:54:51 PM Page 97 Appendix Predeveloped Schematic Treatment 3/31/2026 1:54:52 PM Page 98 Mitigated Schematic Treatment 3/31/2026 1:54:53 PM Page 99 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 Treatment.wdm MESSU 25 PreTreatment.MES 27 PreTreatment.L61 28 PreTreatment.L62 30 POCTreatment1.dat 31 POCTreatment2.dat 32 POCTreatment3.dat 33 POCTreatment4.dat 34 POCTreatment5.dat 35 POCTreatment6.dat 36 POCTreatment7.dat 37 POCTreatment8.dat 38 POCTreatment9.dat 39 POCTreatment10.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 PERLND 17 COPY 501 COPY 502 COPY 503 COPY 504 COPY 505 COPY 506 COPY 507 COPY 508 COPY 509 COPY 510 DISPLY 1 DISPLY 2 DISPLY 3 DISPLY 4 DISPLY 5 DISPLY 6 DISPLY 7 DISPLY 8 DISPLY 9 DISPLY 10 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 2 Basin 2 MAX 1 2 31 9 3 Basin 3 MAX 1 2 32 9 4 Basin 4 MAX 1 2 33 9 5 Basin 5 MAX 1 2 34 9 6 Basin 6 MAX 1 2 35 9 7 Basin 7 MAX 1 2 36 9 8 Basin 8 MAX 1 2 37 9 9 Basin 9 MAX 1 2 38 9 10 Basin 10 MAX 1 2 39 9 Treatment 3/31/2026 1:54:53 PM Page 100 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 503 1 1 504 1 1 505 1 1 506 1 1 507 1 1 508 1 1 509 1 1 510 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 Treatment 3/31/2026 1:54:53 PM Page 101 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 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# *** Basin 1*** PERLND 16 0.59 COPY 501 12 PERLND 16 0.59 COPY 501 13 Treatment 3/31/2026 1:54:53 PM Page 102 IMPLND 1 1.73 COPY 501 15 Basin 2*** IMPLND 1 1.91 COPY 502 15 Basin 3*** PERLND 16 1.57 COPY 503 12 PERLND 16 1.57 COPY 503 13 IMPLND 1 6.2 COPY 503 15 Basin 4*** IMPLND 1 2.72 COPY 504 15 Basin 5*** IMPLND 1 0.25 COPY 505 15 Basin 6*** PERLND 17 0.24 COPY 506 12 PERLND 17 0.24 COPY 506 13 IMPLND 1 1.85 COPY 506 15 Basin 7*** PERLND 17 0.24 COPY 507 12 PERLND 17 0.24 COPY 507 13 IMPLND 1 0.58 COPY 507 15 Basin 8*** PERLND 17 0.33 COPY 508 12 PERLND 17 0.33 COPY 508 13 IMPLND 1 1.02 COPY 508 15 Basin 9*** PERLND 17 1.82 COPY 509 12 PERLND 17 1.82 COPY 509 13 IMPLND 1 1.91 COPY 509 15 Basin 10*** IMPLND 1 0.25 COPY 510 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 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 COPY 503 OUTPUT MEAN 1 1 48.4 DISPLY 3 INPUT TIMSER 1 COPY 504 OUTPUT MEAN 1 1 48.4 DISPLY 4 INPUT TIMSER 1 COPY 505 OUTPUT MEAN 1 1 48.4 DISPLY 5 INPUT TIMSER 1 COPY 506 OUTPUT MEAN 1 1 48.4 DISPLY 6 INPUT TIMSER 1 COPY 507 OUTPUT MEAN 1 1 48.4 DISPLY 7 INPUT TIMSER 1 COPY 508 OUTPUT MEAN 1 1 48.4 DISPLY 8 INPUT TIMSER 1 COPY 509 OUTPUT MEAN 1 1 48.4 DISPLY 9 INPUT TIMSER 1 COPY 510 OUTPUT MEAN 1 1 48.4 DISPLY 10 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 Treatment 3/31/2026 1:54:53 PM Page 103 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 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 502 FLOW ENGL REPL COPY 503 OUTPUT MEAN 1 1 48.4 WDM 503 FLOW ENGL REPL COPY 504 OUTPUT MEAN 1 1 48.4 WDM 504 FLOW ENGL REPL COPY 505 OUTPUT MEAN 1 1 48.4 WDM 505 FLOW ENGL REPL COPY 506 OUTPUT MEAN 1 1 48.4 WDM 506 FLOW ENGL REPL COPY 507 OUTPUT MEAN 1 1 48.4 WDM 507 FLOW ENGL REPL COPY 508 OUTPUT MEAN 1 1 48.4 WDM 508 FLOW ENGL REPL COPY 509 OUTPUT MEAN 1 1 48.4 WDM 509 FLOW ENGL REPL COPY 510 OUTPUT MEAN 1 1 48.4 WDM 510 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 Treatment 3/31/2026 1:54:53 PM Page 104 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 Treatment.wdm MESSU 25 MitTreatment.MES 27 MitTreatment.L61 28 MitTreatment.L62 30 POCTreatment1.dat 31 POCTreatment2.dat 32 POCTreatment3.dat 33 POCTreatment4.dat 34 POCTreatment5.dat 35 POCTreatment6.dat 36 POCTreatment7.dat 37 POCTreatment8.dat 38 POCTreatment9.dat 39 POCTreatment10.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 PERLND 17 COPY 501 COPY 502 COPY 503 COPY 504 COPY 505 COPY 506 COPY 507 COPY 508 COPY 509 COPY 510 DISPLY 1 DISPLY 2 DISPLY 3 DISPLY 4 DISPLY 5 DISPLY 6 DISPLY 7 DISPLY 8 DISPLY 9 DISPLY 10 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 2 Basin 2 MAX 1 2 31 9 3 Basin 3 MAX 1 2 32 9 4 Basin 4 MAX 1 2 33 9 5 Basin 5 MAX 1 2 34 9 6 Basin 6 MAX 1 2 35 9 7 Basin 7 MAX 1 2 36 9 8 Basin 8 MAX 1 2 37 9 9 Basin 9 MAX 1 2 38 9 10 Basin 10 MAX 1 2 39 9 Treatment 3/31/2026 1:54:53 PM Page 105 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 503 1 1 504 1 1 505 1 1 506 1 1 507 1 1 508 1 1 509 1 1 510 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 Treatment 3/31/2026 1:54:53 PM Page 106 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 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# *** Basin 1*** PERLND 16 0.59 COPY 501 12 PERLND 16 0.59 COPY 501 13 Treatment 3/31/2026 1:54:53 PM Page 107 IMPLND 1 1.73 COPY 501 15 Basin 2*** IMPLND 1 1.91 COPY 502 15 Basin 3*** PERLND 16 1.57 COPY 503 12 PERLND 16 1.57 COPY 503 13 IMPLND 1 6.2 COPY 503 15 Basin 4*** IMPLND 1 2.72 COPY 504 15 Basin 5*** IMPLND 1 0.25 COPY 505 15 Basin 6*** PERLND 16 0.24 COPY 506 12 PERLND 16 0.24 COPY 506 13 IMPLND 1 1.85 COPY 506 15 Basin 7*** PERLND 16 0.24 COPY 507 12 PERLND 16 0.24 COPY 507 13 IMPLND 1 0.58 COPY 507 15 Basin 8*** PERLND 16 0.33 COPY 508 12 PERLND 16 0.33 COPY 508 13 IMPLND 1 1.02 COPY 508 15 Basin 9*** PERLND 17 1.82 COPY 509 12 PERLND 17 1.82 COPY 509 13 IMPLND 1 1.91 COPY 509 15 Basin 10*** IMPLND 1 0.25 COPY 510 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 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 COPY 503 OUTPUT MEAN 1 1 48.4 DISPLY 3 INPUT TIMSER 1 COPY 504 OUTPUT MEAN 1 1 48.4 DISPLY 4 INPUT TIMSER 1 COPY 505 OUTPUT MEAN 1 1 48.4 DISPLY 5 INPUT TIMSER 1 COPY 506 OUTPUT MEAN 1 1 48.4 DISPLY 6 INPUT TIMSER 1 COPY 507 OUTPUT MEAN 1 1 48.4 DISPLY 7 INPUT TIMSER 1 COPY 508 OUTPUT MEAN 1 1 48.4 DISPLY 8 INPUT TIMSER 1 COPY 509 OUTPUT MEAN 1 1 48.4 DISPLY 9 INPUT TIMSER 1 COPY 510 OUTPUT MEAN 1 1 48.4 DISPLY 10 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 Treatment 3/31/2026 1:54:53 PM Page 108 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 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 COPY 2 OUTPUT MEAN 1 1 48.4 WDM 702 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 802 FLOW ENGL REPL COPY 3 OUTPUT MEAN 1 1 48.4 WDM 703 FLOW ENGL REPL COPY 503 OUTPUT MEAN 1 1 48.4 WDM 803 FLOW ENGL REPL COPY 4 OUTPUT MEAN 1 1 48.4 WDM 704 FLOW ENGL REPL COPY 504 OUTPUT MEAN 1 1 48.4 WDM 804 FLOW ENGL REPL COPY 5 OUTPUT MEAN 1 1 48.4 WDM 705 FLOW ENGL REPL COPY 505 OUTPUT MEAN 1 1 48.4 WDM 805 FLOW ENGL REPL COPY 6 OUTPUT MEAN 1 1 48.4 WDM 706 FLOW ENGL REPL COPY 506 OUTPUT MEAN 1 1 48.4 WDM 806 FLOW ENGL REPL COPY 7 OUTPUT MEAN 1 1 48.4 WDM 707 FLOW ENGL REPL COPY 507 OUTPUT MEAN 1 1 48.4 WDM 807 FLOW ENGL REPL COPY 8 OUTPUT MEAN 1 1 48.4 WDM 708 FLOW ENGL REPL COPY 508 OUTPUT MEAN 1 1 48.4 WDM 808 FLOW ENGL REPL COPY 9 OUTPUT MEAN 1 1 48.4 WDM 709 FLOW ENGL REPL COPY 509 OUTPUT MEAN 1 1 48.4 WDM 809 FLOW ENGL REPL COPY 10 OUTPUT MEAN 1 1 48.4 WDM 710 FLOW ENGL REPL COPY 510 OUTPUT MEAN 1 1 48.4 WDM 810 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 Treatment 3/31/2026 1:54:53 PM Page 109 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Treatment 3/31/2026 1:54:53 PM Page 110 Predeveloped HSPF Message File Treatment 3/31/2026 1:54:53 PM Page 111 Mitigated HSPF Message File Treatment 3/31/2026 1:54:53 PM Page 112 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. 2005-2026; 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 February 2024 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS), METALS, AND PHOSPHORUS TREATMENT For Oldcastle Infrastructure, Inc.’s The BioPod™ Biofilter (Formerly the TreePod Biofilter) Ecology’s Decision Based on Oldcastle Infrastructure, Inc. application submissions for The BioPod™ Biofilter (BioPod), Ecology hereby issues the following use level designation: 1) General Use Level Designation (GULD) for Basic, Metals, and Phosphorus Treatment: • Sized at a hydraulic loading rate of 1.6 gallons per minute (gpm) per square foot (sq ft) of media surface area. • Constructed with a minimum media thickness of 18-inches (1.5-feet) 2) Ecology approves the BioPod at the hydraulic loading rate listed above, to achieve the maximum water quality design flow rate. The water quality design flow rates are calculated using the following procedures: • Western Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology- approved continuous runoff model. • Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three methods described in Chapter 2.7.6 of the Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual. • Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. 3) For systems that have a drain down outlet, designers must increase the water quality design flow rate calculated in Item 2, above, to account for the water that will enter the initial bay but won’t be treated by the engineered soil. Multiply the flow rate determined above by 1.05 to determine the required flowrate for the BioPod unit. 4) Oldcastle produces alternative configurations of the version tested for TAPE approval. The system tested is the named the BioPod Planter. Alternative configurations that are also approved for use through this GULD are the BioPod Surface, the BioPod Tree, and the BioPod Underground. 5) The GULD has no expiration date, but may be amended or revoked by Ecology. Ecology’s Conditions of Use The BioPod shall comply with these conditions: 1) Applicants shall design, assemble, install, operate, and maintain the BioPod installations in accordance with Oldcastle Infrastructure Inc.’s applicable manuals and the Ecology Decision. 2) The minimum size filter surface-area for use in Washington is determined by using the design water quality flow rate (as determined in Ecology Decision, Item 3, above) and the hydraulic loading rate (as identified in Ecology Decision, Item 1, above). Calculate the required area by dividing the water quality design flow rate (cu-ft/sec) by the hydraulic loading rate (converted to ft/sec) to obtain the required surface area (sq ft) of the BioPod unit. 3) BioPod media shall conform to the specifications submitted to and approved by Ecology. 4) The applicant tested the BioPod without plants. This GULD applies to the BioPod Stormwater Treatment System whether plants are included in the final product or not. 5) Maintenance: The required inspection/maintenance interval for stormwater treatment devices is often dependent on the efficiency of the device and the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a particular model/size of manufactured filter treatment device. • The BioPod is designed for a target maintenance interval of 1 year. Maintenance includes replacing the mulch, assessing plant health, removal of trash, and raking the top few inches of engineered media. • The BioPod system initially tested at the Lake Union Ship Canal Test Facility in Seattle, WA required maintenance after 1.5 months, or 6.3% of a water year. Monitoring personnel observed similar maintenance issues with other systems evaluated at the Test Facility. Runoff from the Test Facility may be unusual and maintenance requirements of systems installed at the Test Facility may not be indicative of typical maintenance requirements. Because of this, the initial version of the GULD required Oldcastle to subsequently “conduct hydraulic testing to obtain information about maintenance requirements on a site with runoff that is more typical of the Pacific Northwest”. Quarterly testing from a 15-month maintenance frequency assessment conducted on a BioPod system installed along a roadway in Des Moines, WA indicated the system was able to treat a full water year before requiring maintenance. • Test results provided to Ecology from a BioPod System evaluated in a lab following New Jersey Department of Environmental Protection Laboratory Protocol for Filtration MTDs have indicated the BioPod System is capable of longer maintenance intervals. • Owners/operators must inspect BioPod systems for a minimum of twelve months from the start of post-construction operation to determine site-specific inspection/maintenance schedules and requirements. Owners/operators must conduct inspections monthly during the wet season, and every other month during the dry season. (According to the SWMMWW, the wet season in western Washington is October 1 to April 30. According to the SWMMEW, the wet season in eastern Washington is October 1 to June 30.) After the first year of operation, owners/operators must conduct inspections based on the findings during the first year of inspections. • Conduct inspections by qualified personnel, follow manufacturer’s guidelines, and use methods capable of determining either a decrease in treated effluent flow rate and/or a decrease in pollutant removal ability. 6) Install the BioPod in such a manner that you bypass flows exceeding the maximum operating rate and you will not resuspend captured sediment. 7) Discharges from the BioPod shall not cause or contribute to water quality standard violations in receiving waters. Approved Alternate Configurations BioPod Internal Bypass 1) The BioPod Internal Bypass configuration may be combined with a Curb Inlet, Grated Inlet, and Piped-In Inlet. Water quality flows and peak flows are directed from the curb, overhead grate, or piped inlet to a contoured inlet rack. The inlet rack disperses water quality flows over the top surface of the biofiltration chamber. Excess flows are diverted over a curved bypass weir to the outlet area without passing through the treatment area. Both water quality flows and bypass flows are combined in the outlet area prior to being discharged out of the system. 2) To select a BioPod Internal Bypass unit, the designer must determine the size of the standard unit using the sizing guidance described above. Systems that have an internal bypass may use the off-line water quality design flow rate. 3) The internal bypass configuration has a maximum flow rate of 900 gallons per minute. Sites where the anticipated flow rate at the treatment device is larger than 900 gpm must use an external bypass, or size the treatment device for the on-line water quality design flow rate. Applicant: Oldcastle Infrastructure, Inc. Applicant’s Address: 7100 Longe St, Suite 100 Stockton, CA 95206 Application Documents: BioPod™ Stormwater Filter Maintenance Frequency Assessment, Prepared for Oldcastle Infrastructure, Inc., Prepared by Herrera Environmental Consultants, Inc. February 2022 Technical Evaluation Report TreePod™ BioFilter System Performance Certification Project, Prepared for Oldcastle, Inc., Prepared by Herrera Environmental Consultants, Inc. February 2018 Technical Memorandum: Response to Board of External Reviewers’ Comments on the Technical Evaluation Report for the TreePod™ Biofilter System Performance Certification Project, Oldcastle, Inc. and Herrera Environmental Consultants, Inc., February 2018 Technical Memorandum: Response to Board of External Reviewers’ Comments on the Technical Evaluation Report for the TreePod™ Biofilter System Performance Certification Project, Oldcastle, Inc. and Herrera Environmental Consultants, Inc., January 2018 Application for Pilot Use Level Designation, TreePod™ Biofilter – Stormwater Treatment System, Oldcastle Stormwater Solutions, May 2016 Emerging Stormwater Treatment Technologies Application for Certification: The TreePod™ Biofilter, Oldcastle Stormwater Solutions, April 2016 Applicant’s Use Level Request: • General Use Level Designation as a Basic, Metals, and Phosphorus Treatment device in accordance with Ecology’s Stormwater Management Manual for Western Washington Applicant’s Performance Claims: Based on results from laboratory and field-testing, the applicant claims the BioPod™ Biofilter operating at a hydraulic loading rate of 153 inches per hour is able to remove: • 80% of Total Suspended Solids (TSS) for influent concentrations greater than 100 mg/L and achieve a 20 mg/L effluent for influent concentrations less than 100 mg/L. • 60% dissolved zinc for influent concentrations 0.02 to 0.3 mg/L. • 30% dissolved copper for influent concentrations 0.005 to 0.02 mg/L. • 50% or greater total phosphorus for influent concentrations 0.1 to 0.5 mg/L. Ecology’s Recommendations: Ecology finds that: • Oldcastle Infrastructure, Inc. has shown Ecology, through laboratory and field testing, that the BioPod™ Biofilter is capable of attaining Ecology’s Basic, Total Phosphorus, and Metals treatment goals. Findings of Fact: Field Testing • Herrera Environmental Consultants, Inc. conducted monitoring of the BioPod™ Biofilter at the Lake Union Ship Canal Test Facility in Seattle Washington between November 2016 and April 2018. Herrera collected flow-weight composite samples during 14 separate storm events and peak flow grab samples during 3 separate storm events. The system was sized at an infiltration rate of 153 inches per hour or a hydraulic loading rate of 1.6 gpm/ft2. o The D50 of the influent PSD ranged from 3 to 292 microns, with an average D50 of 28 microns. o Influent TSS concentrations ranged from 17 mg/L to 666 mg/L, with a mean concentration of 98 mg/L. For all samples (influent concentrations above and below 100 mg/L) the bootstrap estimate of the lower 95 percent confidence limit (LCL 95) of the mean TSS reduction was 84% and the bootstrap estimate of the upper 95 percent confidence limit (UCL95) of the mean TSS effluent concentration was 8.2 mg/L. o Dissolved copper influent concentrations from the 17 events ranged from 9.0 µg/L to 21.1 µg/L. The 21.1 µg/L data point was reduced to 20.0 µg/L, the upper limit to the TAPE allowed influent concentration range, prior to calculating the pollutant removal. A bootstrap estimate of the LCL95 of the mean dissolved copper reduction was 35%. o Dissolved zinc influent concentrations from the 17 events ranged from 26.1 µg/L to 43.3 µg/L. A bootstrap estimate of the LCL95 of the mean dissolved zinc reduction was 71%. o Total phosphorus influent concentrations from the 17 events ranged from 0.064 mg/L to 1.56 mg/L. All influent data greater than 0.5 mg/L were reduced to 0.5 mg/L, the upper limit to the TAPE allowed influent concentration range, prior to calculating the pollutant removal. A bootstrap estimate of the LCL95 of the mean total phosphorus reduction was 64%. o The system experienced rapid sediment loading and needed to be maintained after 1.5 months. Monitoring personnel observed similar sediment loading issues with other systems evaluated at the Test Facility. The runoff from the Test Facility may not be indicative of maintenance requirements for all sites. • Herrera Environmental Consultants, Inc. conducted a maintenance frequency assessment of the BioPod™ installed along a roadway in Des Moines, WA between September 2020 and January 2022. o Herrera collected influent grab samples during 10 storm events and paired effluent samples during 5 storm events. Influent concentrations ranged from 1 mg/L to 164 mg/L, with a median concentration of 23 mg/L. Effluent concentrations ranged from 1 mg/L to 19 mg/L, with a median of 5 mg/L. o Herrera collected influent PSD samples during 3 storm events. The D50 for the samples were 42, 1306, and 57 microns. The 1306 micron value was collected during an event with an influent TSS concentration of 1 mg/L. It is assumed this sample was atypical and that it contained a few grains of very coarse sand and almost no other particles. o Herrera used a water truck to conduct flow testing 7 times to assess how long the system could filter at the design flow rate without bypass. Results show the system was able to treat up to a full water year before the system needed maintenance. Laboratory Testing • Good Harbour Laboratories (GHL) conducted laboratory testing at their site in Mississauga, Ontario in October 2017 following the New Jersey Department of Environmental Protection Laboratory Protocol for Filtration MTDs. The testing evaluated a 4-foot by 6-foot standard biofiltration chamber and inlet contour rack with bypass weir. The test sediment used during the testing was custom blended by GHL using various commercially available silica sands, which had an average d50 of 69 µm. Based on the lab test results: o GHL evaluated removal efficiency over 15 events at a Maximum Treatment Flow Rate (MTFR) of 37.6 gpm, which corresponds to a MTFR to effective filtration treatment area ratio of 1.80 gpm/ft2. The system, operating at 100% of the MTFR with an average influent concentration of 201.3 mg/L, had an average removal efficiency of 99 percent. o GHL evaluated sediment mass loading capacity over an additional 16 events using an influent SSC concentration of 400 mg/L. The first 11 runs were evaluated at 100% of the MTFR. The BioPod began to bypass, so the remaining 5 runs were evaluated at 90% of the MTFR. The total mass of the sediment captured was 245.0 lbs and the cumulative mass removal efficiency was 96.3%. • Herrera Environmental Consultants Inc. conducted laboratory testing in September 2014 at the Seattle University Engineering Laboratory. The testing evaluated the flushing characteristics, hydraulic conductivity, and pollutant removal ability of twelve different media blends. Based on this testing, Oldcastle Infrastructure, Inc. selected one media blend, Mix 8, for inclusion in their TAPE evaluation of the BioPod™ Biofilter. o Herrera evaluated Mix 8 in an 8-inch diameter by 36-inch tall polyvinyl chloride (PVC) column. The column contained 18-inches of Mix 8 on top of 6-inches of pea gravel. The BioPod will normally include a 3-inch mulch layer on top of the media layer; however, this was not included in the laboratory testing. o Mix 8 has a hydraulic conductivity of 218 inches per hour; however, evaluation of the pollutant removal ability of the media was based on an infiltration rate of 115 inches per hour. The media was tested at 75%, 100%, and 125% of the infiltration rate. Based on the lab test results: • The system was evaluated using natural stormwater. The dissolved copper and dissolved zinc concentrations in the natural stormwater were lower than the TAPE influent standards; therefore, the stormwater was spiked with 66.4 mL of 100 mg/L Cu solution and 113.6 mL of 1,000 mg/L Zn solution. • The BioPod removed an average of 81% of TSS, with a mean influent concentration of 48.4 mg/L and a mean effluent concentration of 9.8 mg/L. • The BioPod removed an average of 94% of dissolved copper, with a mean influent concentration of 10.6 µg/L and a mean effluent concentration of 0.6 µg/L. • The BioPod removed an average of 97% of dissolved zinc, with a mean influent concentration of 117 µg/L and a mean effluent concentration of 4 µg/L. • The BioPod removed an average of 97% of total phosphorus, with a mean influent concentration of 2.52 mg/L and a mean effluent concentration of 0.066 mg/L. When total phosphorus influent concentrations were capped at the TAPE upper limit of 0.5 mg/L, calculations showed an average removal of 87%. Other BioPod Related Issues to be Addressed by the Company: 1. None identified at this time. Technology Description: Download at https://oldcastleprecast.com/stormwater/bioretention- biofiltration-applications/bioretention-biofiltration- solutions/ Contact Information: Applicant: Chris Demarest Oldcastle Infrastructure, Inc. (925)667-7100 Chris.demarest@oldcastle.com Applicant website: https://oldcastleprecast.com/stormwater/ Ecology web link: https://ecology.wa.gov/Regulations-Permits/Guidance-technical- assistance/Stormwater-permittee-guidance-resources/Emerging-stormwater-treatment- technologies Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 870-0983 douglas.howie@ecy.wa.gov Revision History Date Revision March 2018 GULD granted for Basic Treatment March 2018 Provisional GULD granted for Enhanced and Phosphorus Treatment June 2016 PULD Granted April 2018 GULD for Basic and Provisional GULD for Enhanced and Phosphorus granted, changed name to BioPod from TreePod July 2018 GULD for Enhanced and Phosphorus granted September 2018 Changed Address for Oldcastle December 2018 Added minimum media thickness requirement May 2019 Changed language on who must Install and maintain the device from Oldcastle to Applicants August 2019 Added text on sizing using infiltration rate and water quality design flow rate October 2019 Added text describing ability to use off-line design water quality flow rate for sizing due to internal bypass December 2021 Extended approval to installations without plants, added sizing adjustment when using facilities with a drawdown outlet March 2022 Added results from the maintenance frequency assessment to the Ecology’s Conditions of Use and the Findings of Fact sections January 2024 Revised Dissolved Metals (Enhanced) to Metals February 2024 Added manufacturers names for the tested unit and the three alternative configurations to the text. 1 April 2025 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS), METALS, PHOSPHORUS & OIL TREATMENT For CONTECH Engineered Solutions Filterra® Ecology’s Decision: Based on the Contech Engineered Solution’s (Contech) submissions for the Filterra® system, Ecology hereby issues the following use level designation: 1. A General Use Level Designation for Basic, Metals, Phosphorus, and Oil Treatment for the Filterra system constructed with a minimum media thickness of 21 inches (1.75 feet), at the following water quality design hydraulic loading rates: Treatment Infiltration Rate (in/hr) for use in Sizing Basic 324 Phosphorus 324 Oils 50 Metals 324 2. The Filterra is not appropriate for oil spill-control purposes. 3. Maintenance data collected during the initial TAPE GULD testing and the post GULD maintenance assessment demonstrated the system was able to treat the following percentage of a water year before needing maintenance: Site Location Land Use Average TSS (mg/L) D50 PSD (µm) Maintenance Cycle1 (% water year) GULD Testing2 Hillsboro, OR Commercial 57 143 723 Maintenance4 Assessment 1 Ecology recommends considering maintenance cycle information when sizing the system. Sizing may need to be increased to meet the project, permit, or jurisdiction maintenance cycle. 2 GULD Testing data is based on 2021-2023 field evaluation that was done to support an infiltration rate of 324 in/hr. 3 Percent water year between maintenance events was not reported. On average maintenance was completed every 8.6 months which was estimated as 72% of a water year. Maintenance was performed according to manufacturer’s typical recommendation and not due to premature bypass or evidence of system occlusion. 4 Maintenance assessment data are collected after issuing of the GULD. Maintenance assessment must be completed on a standard precast Filterra or Filterra Bioscape and shall be completed by February 28, 2028. 2 4. Ecology approves Filterra systems for treatment at the hydraulic loading rates listed above, and sized based on the water quality design flow rate for an off-line system. Calculate the water quality design flow rates using the following procedures: • Western Washington: for treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using the latest version of the Western Washington Hydrology Model or other Ecology-approved continuous runoff model and as described in section III-2.6 of the 2024 Stormwater Management Manual for Western Washington (SWMMWW) • Eastern Washington: For treatment installed upstream of detention or retention, the water quality design flow rate is the peak 15-minute flow rate as calculated using one of the three methods described in Chapter 6.5.1 of the 2024 Stormwater Management Manual for Eastern Washington (SWMMEW) or local manual. • Entire State: For treatment installed downstream of detention, the water quality design flow rate is the full 2-year release rate of the detention facility. 5. This General Use Level Designation has no expiration date, but Ecology may revoke or amend the designation, and is subject to the conditions specified below. Ecology’s Conditions of Use: Filterra systems shall comply with these conditions shall comply with the following conditions: 1. Design, assemble, install, operate, and maintain the Filterra systems in accordance with applicable Contech Filterra manuals and this Ecology Decision. 2. The minimum size filter surface-area for use in Washington is determined by using the design water quality flow rate (as determined in this Ecology Decision, Item 3, above) and the Infiltration Rate from the table above (use the lowest applicable Infiltration Rate depending on the level of treatment required). Calculate the required area by dividing the water quality design flow rate (cu-ft/sec) by the Infiltration Rate (converted to ft/sec) to obtain required surface area (sq-ft) of the Filterra unit. 3. Each site plan must undergo Contech Filterra review before Ecology can approve the unit for site installation. This will ensure that design parameters including site grading and slope are appropriate for use of a Filterra unit. 4. Filterra media shall conform to the specifications submitted to and approved by Ecology and shall be sourced from Contech with no substitutions. 5. Contech tested the Filterra with and without plants. The GULD applies to the Filterra whether plants are included in the final product or not. 6. Maintenance: The required maintenance interval for stormwater treatment devices is often dependent upon the degree of pollutant loading from a particular drainage basin. Therefore, Ecology does not endorse or recommend a “one size fits all” maintenance cycle for a particular model/size of manufactured treatment device. • Contech designs Filterra systems for a target maintenance interval of 6 months in the Pacific Northwest. Maintenance includes removing and replacing the mulch layer above 3 the media along with accumulated sediment, trash, and captured organic materials therein, evaluating plant health, and pruning the plant if deemed necessary. • Owners/operators must inspect the Filterra system for a minimum of twelve months from the start of post-construction operation to determine site-specific inspection/maintenance schedules and requirements. Owners/operators must conduct inspections monthly during the wet season, and every other month during the dry season (According to the SWMMWW, the wet season in western Washington is October 1 to April 30. According to the SWMMEW, the wet season in eastern Washington is October 1 to June 30). After the first year of operation, owners/operators must conduct inspections based on the findings during the first year of inspections. 7. Conduct maintenance following manufacturer’s guidelines. Follow maintenance procedures given in the most recent version of the Filterra Operation and Maintenance Manual. 8. Filterra systems come in standard sizes. 9. Install the Filterra in such a manner that flows exceeding the maximum operating rate are conveyed around the mulch and media and will not resuspend captured sediment. 10. Discharges from the Filterra units shall not cause or contribute to water quality standards violations in receiving waters. Approved Alternate Configurations Filterra Internal Bypass - Pipe (FTIB-P) 1. The Filterra® Internal Bypass – Pipe allows for piped-in flow from area drains, grated inlets, trench drains, and/or roof drains. Design capture flows and peak flows enter the structure through an internal slotted pipe. Filterra® inverted the slotted pipe to allow design flows to drop through to a series of splash plates that then disperse the design flows over the top surface of the Filterra® planter area. Higher flows continue to bypass the slotted pipe and convey out the structure. 2. To select a FTIB-P unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterra Internal Bypass – Curb (FTIB-C) 1. The Filterra® Internal Bypass –Curb model (FTIB-C) incorporates a curb inlet, biofiltration treatment chamber, and internal high flow bypass in one single structure. Filterra® designed the FTIB-C model for use in a “Sag” or “Sump” condition and will accept flows from both directions along a gutter line. An internal flume tray weir component directs treatment flows entering the unit through the curb inlet to the biofiltration treatment chamber. Flows in excess of the water quality treatment flow rise above the flume tray weir and discharge through a standpipe orifice; providing bypass of untreated peak flows. Americast manufactures the FTIB-C model in a variety of sizes and configurations and you may use the unit on a continuous grade when a single structure providing both treatment and high flow bypass is preferred. The FTIB-C model can also incorporate a separate junction box chamber to allow larger diameter discharge pipe connections to the structure. 4 2. To select a FTIB-C unit, the designer must determine the size of the standard unit using the sizing guidance described above. Filterra® Shallow 1. The Filterra Shallow provides additional flexibility for design engineers and designers in situations where various elevation constraints prevent application of a standard Filterra configuration. Engineers can design this system up to six inches shallower than any of the previous Filterra unit configurations noted above. 2. Ecology requires that the Filterra Shallow provide a media contact time equivalent to that of the standard unit. This means that with a smaller depth of media, the surface area must increase. 3. To select a Filterra Shallow System unit, the designer must first identify the size of the standard unit using the modeling guidance described above. 4. Once the size of the standard Filterra unit is established using the sizing technique described above, use information from the following table to select the appropriate size Filterra Shallow System unit. Shallow Unit Basic, Metals, Phosphorus, and Oil Treatment Sizing Standard Depth Equivalent Shallow Depth 4x4 4x6 or 6x4 4x6 or 6x4 6x6 4x8 or 8x4 6x8 or 8x6 6x6 6x10 or 10x6 6x8 or 8x6 6x12 or 12x6 6x10 or 10x6 13x7 Notes: 1. Shallow Depth Boxes are less than the standard depth of 3.5 feet but no less than 3.0 feet deep (TC to INV). Applicant: Contech Engineered Solutions, LLC. Applicant’s Address: 12901 SE 97th Ave, Suite 400 Clackamas, OR 97015 Application Documents: State of Washington Department of Ecology Application for Conditional Use Designation, Americast (September 2006) Quality Assurance Project Plan Filterra® Bioretention Filtration System Performance Monitoring, Americast (April 2008) Quality Assurance Project Plan Addendum Filterra® Bioretention Filtration System Performance Monitoring, Americast (June 2008) 5 Draft Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (August 2009) Final Technical Evaluation Report Filterra® Bioretention Filtration System Performance Monitoring, Americast (December 2009) Technical Evaluation Report Appendices Filterra® Bioretention Filtration System Performance Monitoring, Americast, (August 2009) Memorandum to Department of Ecology Dated October 9, 2009 from Americast, Inc. and Herrera Environmental Consultants Quality Assurance Project Plan Filterra® Bioretention System Phosphorus treatment and Supplemental Basic and Enhanced Treatment Performance Monitoring, Americast (November 2011) Filterra® letter August 24, 2012 regarding sizing for the Filterra® Shallow System. University of Virginia Engineering Department Memo by Joanna Crowe Curran, Ph. D dated March 16, 2013 concerning capacity analysis of Filterra® internal weir inlet tray. Terraphase Engineering letter to Jodi Mills, P.E. dated April 2, 2013 regarding Terraflume Hydraulic Test, Filterra® Bioretention System and attachments. Technical Evaluation Report, Filterra® System Phosphorus Treatment and Supplemental Basic Treatment Performance Monitoring. March 27th, 2014. State of Washington Department of Ecology Application for Conditional Use Level Designation, Contech Engineered Solutions (May 2015) Quality Assurance Project Plan Filterra® Bioretention System, Contech Engineered Solutions (May 2015) Filterra Bioretention System Armco Avenue General Use Level Designation Technical Evaluation Report, Contech Engineered Solutions (August 2019) NJCAT Technology Verification, Filterra Bioretention System, Contech Engineered Solutions (October 2020) Basic Treatment PULD Application for Contech Enhanced Filtration System, Contech Engineered Solutions (November 2020) Contech Enhanced Filtration System, Application for Certification, Contech Engineered Solutions (November 2020) Quality Assurance Project Plan Contech Enhanced Filtration System (CEFS) Technology Performance Evaluation, Prepared by Contech Engineered Solutions (September 2021) Addendum to the Quality Assurance Project Plan – Contech Enhanced Filtration System, Prepared by Contech Engineered Solutions (August 2021) Contech Enhanced Filtration System Armco Avenue General Use Level Designation Technical Evaluation Report, Prepared by Contech Engineered Solutions (May 2024) Applicant’s Use Level Request: General Level Use Designation as a Basic, Metals, Phosphorus, and Oil Treatment device in accordance with Ecology’s Stormwater Management Manual for Western Washington. Applicant’s Performance Claims: Based on field testing, the Filterra is able to meet TAPE performance goals for TSS, dissolved metals, and total phosphorus at an infiltration rate of 324 in/hr, and is able to meet TAPE 6 performance goals for oil at an infiltration rate of 50 in/hr. Ecology’s Recommendations: Ecology finds that Contech has shown Ecology, through laboratory and field testing, that the Filterra is capable of attaining Ecology’s Basic, Metals, Phosphorus, and Oil treatment goals. Findings of Fact: Field Testing 2021-2023 1. Contech completed field testing of a 4 ft. x 3 ft. unvegetated Filterra unit (referred to as a Contech Enhanced Filtration System [CEFS] during testing) in Hillsboro, Oregon between June 2021 and April 2023. Throughout the monitoring period a total of 35 individual storm events were sampled. 2. The CEFS utilized the same media formulation and dimensional layout as a Filterra unit but did not include plants. 3. Contech evaluated the system for basic, metals, and phosphorus treatment against a hydraulic loading rate of 3.36 gpm/sf (324 in/hr). 4. Herrera Environmental Consultants conducted a third-party review of the data and TER to ensure the monitoring complied with the QAPP and met the requirements of the TAPE guidance document. 5. Particle size distribution analysis showed 39% of the influent particulate finer than 62.5 microns (µm) for the samples collected during the 35-event period. Performance analysis based on serial filtration demonstrated that TSS for a majority-silt sediment range met Basic treatment requirements with an upper 95 percent confidence limit (UCL95) effluent concentration of 18.8 mg/L. 6. The similarity of influent and effluent PSD prompted a review of the influence of laboratory procedure on the results. Upon recommendation of Herrera Environmental Consultants, a secondary laboratory was consulted which provided TAPE PSD analysis on multiple previous TAPE testing campaigns, including the Ship Canal test site. Six supplemental events were sampled for PSD between 1/4/24 and 2/16/24, and sample splits were sent for comparative analysis by both laboratories. Results from the second laboratory showed 77% of influent particulate finer than 62.5 microns (µm). Average influent D50 results for the six events were 159 µm and 12 µm for the original and secondary laboratories, respectively. 7. Of the 35 sampled events, 21 met requirements for TSS analysis. Influent TSS concentrations ranged from 20 mg/L to 269 mg/L, with a mean concentration of 57 mg/L. For samples with an influent concentration between 20 and 100 mg/L (n=17) the upper 95 percent confidence limit of the mean TSS effluent concentration was 17.5 mg/L. For samples with an influent concentration greater than 100 mg/L (n=4) the lower 95 percent confidence limit of the mean TSS reduction was 83.5%. Influent concentrations greater than 200 mg/L (the upper end of the TAPE influent concentration range) were capped at 200 mg/L before calculating the pollutant removal efficiency. 8. Of the 35 sampled events, 27 met requirements for dissolved copper analysis. Influent dissolved copper concentrations ranged from 7.3 µg/L to 46.0 µg/L, with a mean 7 concentration of 18.1 µg/L. The lower 95 percent confidence limit of the mean dissolved copper reduction was 39.8%. Influent concentrations greater than 20 µg/L (the upper end of the TAPE influent concentration range) were capped at 20 µg/L before calculating the pollutant removal efficiency. 9. Of the 35 sampled events, 28 met requirements for dissolved zinc analysis. Influent dissolved zinc concentrations ranged from 33.9 µg/L to 178.0 µg/L, with a mean concentration of 74.4 µg/L. The lower 95 percent confidence limit of the mean dissolved zinc reduction was 62.4%. 10. Of the 35 sampled events, 16 met requirements for the total phosphorus analysis. Influent total phosphorus concentrations ranged from 0.101 mg/L to 0.571 mg/L with a mean concentration of 0.298 mg/L. The lower 95 percent confidence limit of the mean total phosphorus reduction was 64.4%. 11. Maintenance was conducted 3 times during the 23-month study period with frequency ranging from every 4 to 9 months. Maintenance performed consisted of replacing the mulch layer. Field Testing 2015-2019 1. Contech completed field testing of a 4 ft. x 4 ft. Filterra unit at one site in Hillsboro, Oregon from September 2015 to July 2019. Throughout the monitoring period a total of 24 individual storm events were sampled, of which 23 qualified for TAPE sampling criteria. 2. Contech encountered several unanticipated events and challenges that prevented them from collecting continuous flow and rainfall data. An analysis of the flow data from the sampled events, including both the qualifying and non-qualifying events, demonstrated the system treated over 99% of the influent flows. Peak flows during these events ranged from 25% to 250% of the design flow rate of 29 gallons per minute. 3. Of the 23 TAPE qualified sample events, 13 met requirements for TSS analysis. Influent concentrations ranged from 20.8 mg/L to 83 mg/L, with a mean concentration of 46.3 mg/L. The UCL95 mean effluent concentration was 15.9 mg/L, meeting the 20 mg/L performance goal for Basic Treatment. 4. All 23 TAPE qualified sample events met requirements for dissolved zinc analysis. Influent concentrations range from 0.0384 mg/L to 0.2680 mg/L, with a mean concentration of 0.0807 mg/L. The LCL 95 mean percent removal was 62.9%, meeting the 60% performance goal for Metals Treatment. 5. Thirteen of the 23 TAPE qualified sample events met requirements for dissolved copper analysis. Influent concentrations ranged from 0.00543 mg/L to 0.01660 mg/L, with a mean concentration of 0.0103 mg/L. The LCL 95 mean percent removal was 41.2%, meeting the 30% performance goal for Metals Treatment. 6. Total zinc concentrations were analyzed for all 24 sample events. Influent EMCs for total zinc ranged from 0.048 mg/L to 5.290 mg/L with a median of 0.162 mg/L. Corresponding effluent EMCs for total zinc ranged from 0.015 mg/L to 0.067 mg/L with a median of 0.029 mg/L. Total event loadings for the study for total zinc were 316.85 g at the influent and 12.92 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 95.9%. 8 7. Total copper concentrations were analyzed for all 24 sample events. Influent EMCs for total copper ranged from 0.003 mg/L to 35.600 mg/L with a median value of 0.043 mg/L. Corresponding effluent EMCs for total copper ranged from 0.002 mg/L to 0.015 mg/L with a median of 0.004 mg/L. Total event loadings for total copper for the study were 1,810.06 g at the influent and 1.90 g at the effluent sampling location, resulting in a summation of loads removal efficiency of 99.9%. Field Testing 2013 1. Filterra completed field-testing of a 6.5 ft x 4 ft. unit at one site in Bellingham, Washington. Continuous flow and rainfall data collected from January 1, 2013 through July 23, 2013 indicated that 59 storm events occurred. Water quality data was obtained from 22 storm events. Not all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 2. The system treated 98.9% of the total 8-month runoff volume during the testing period. Consequently, the system achieved the goal of treating 91% of the volume from the site. Stormwater runoff bypassed Filterra treatment during four of the 59 storm events. 3. Of the 22 sampled events, 18 qualified for TSS analysis (influent TSS concentrations ranged from 25 to 138 mg/L). The data were segregated into sample pairs with influent concentration greater than and less than 100 mg/L. The UCL95 mean effluent concentration for the data with influent less than 100 mg/L was 5.2 mg/L, below the 20- mg/L threshold. Although the TAPE guidelines do not require an evaluation of TSS removal efficiency for influent concentrations below 100 mg/L, the mean TSS removal for these samples was 90.1%. Average removal of influent TSS concentrations greater than 100 mg/L (three events) was 85%. In addition, the system consistently exhibited TSS removal greater than 80% at flow rates equivalent to a 100 in/hr infiltration rate and was observed at 150 in/hr. 4. Ten of the 22 sampled events qualified for TP analysis. Americast augmented the dataset using two sample pairs from previous monitoring at the site. Influent TP concentrations ranged from 0.11 to 0.52 mg/L. The mean TP removal for these twelve events was 72.6%. The LCL95 mean percent removal was 66.0, well above the TAPE requirement of 50%. Treatment above 50% was evident at 100 in/hr infiltration rate and as high as 150 in/hr. Consequently, the Filterra test system met the TAPE Phosphorus Treatment goal at 100 in/hr. Influent ortho-P concentrations ranged from 0.005 to 0.012 mg/L; effluent ortho-P concentrations ranged from 0.005 to 0.013 mg/L. The reporting limit/resolution for the ortho-P test method is 0.01 mg/L, therefore the influent and effluent ortho-P concentrations were both at and near non-detect concentrations. Field Testing 2008-2009 1. Filterra completed field-testing at two sites at the Port of Tacoma. Continuous flow and rainfall data collected during the 2008-2009 monitoring period indicated that 89 storm events occurred. The monitoring obtained water quality data from 27 storm events. Not 9 all the sampled storms produced information that met TAPE criteria for storm and/or water quality data. 2. During the testing at the Port of Tacoma, 98.96 to 99.89% of the annual influent runoff volume passed through the POT1 and POT2 test systems respectively. Stormwater runoff bypassed the POT1 test system during nine storm events and bypassed the POT2 test system during one storm event. Bypass volumes ranged from 0.13% to 15.3% of the influent storm volume. Both test systems achieved the 91% water quality treatment-goal over the 1-year monitoring period. 3. Consultants observed infiltration rates as high as 133 in/hr during the various storms. Filterra did not provide any paired data that identified percent removal of TSS, metals, oil, or phosphorus at an instantaneous observed flow rate. 4. The maximum storm average hydraulic loading rate associated with water quality data is <40 in/hr, with the majority of flow rates < 25 in/hr. The average instantaneous hydraulic loading rate ranged from 8.6 to 53 in/hr. 5. The field data showed a removal rate greater than 80% for TSS with an influent concentration greater than 20 mg/L at an average instantaneous hydraulic loading rate up to 53 in/hr (average influent concentration of 28.8 mg/L, average effluent concentration of 4.3 mg/L). 6. The field data showed a removal rate generally greater than 54% for dissolved zinc at an average instantaneous hydraulic loading rate up to 60 in/hr and an average influent concentration of 0.266 mg/L (average effluent concentration of 0.115 mg/L). 7. The field data showed a removal rate generally greater than 40% for dissolved copper at an average instantaneous hydraulic loading rate up to 35 in/hr and an average influent concentration of 0.0070 mg/L (average effluent concentration of 0.0036 mg/L). 8. The field data showed an average removal rate of 93% for total petroleum hydrocarbon (TPH) at an average instantaneous hydraulic loading rate up to 53 in/hr and an average influent concentration of 52 mg/L (average effluent concentration of 2.3 mg/L). The data also shows achievement of less than 15 mg/L TPH for grab samples. Filterra provided limited visible sheen data due to access limitations at the outlet monitoring location. 9. The field data showed low percentage removals of total phosphorus at all storm flows at an average influent concentration of 0.189 mg/L (average effluent concentration of 0.171 mg/L). We may relate the relatively poor treatment performance of the Filterra system at this location to influent characteristics for total phosphorus that are unique to the Port of Tacoma site. It appears that the Filterra system will not meet the 50% removal performance goal when the majority of phosphorus in the runoff is expected to be in the dissolved form. Laboratory Testing 1. Contech conducted testing of a 4 ft. x 4 ft. unit in July 2020 at Contech’s laboratory in Ashland, Virginia. The unit included the Filterra® HC media blend without the use of any vegetation that is standard in Filterra installations. • The laboratory testing was performed in accordance with the New Jersey Department of Environmental Protection (NJDEP) Laboratory Protocol to Assess Total 10 Suspended Solids Removal by a Filtration Manufactured Treatment Device. Since Contech did the testing, A. Morton Thomas and Associates, inc. performed independent third-party observation. • The testing evaluated a full-scale 4 ft. x 4 ft. unit at a hydraulic loading rate of 3.12 gpm/sq. ft (300 in/hr). The test sediment used with compliant with the NJDEP particle size distribution requirements, with a d50 particle size of 69 µm. • Contech evaluated TSS removal efficiency over 15 events. The influent concentration ranged from 182 mg/L to 211 mg/L with a mean concentration of 200.7 mg/L and a mean removal efficiency of 86%. • Contech evaluated sediment mass loading capacity over an additional 21 events as a continuation of the removal efficiency testing. During the sediment mass loading capacity evaluation Contech increased the target influent concentration to 400 mg/L. The cumulative removal efficiency over the 36 events was 82% and the cumulative mass captured was 110 kg. 2. Filterra performed laboratory testing on a scaled down version of the Filterra unit. The lab data showed an average removal from 83-91% for TSS with influents ranging from 21 to 320 mg/L, 82-84% for total copper with influents ranging from 0.94 to 2.3 mg/L, and 50-61% for orthophosphate with influents ranging from 2.46 to 14.37 mg/L. • Filterra conducted permeability tests on the soil media. • Lab scale testing using Sil-Co-Sil 106 showed removals ranging from 70.1% to 95.5% with a median removal of 90.7%, for influent concentrations ranging from 8.3 to 260 mg/L. Filterra ran these laboratory tests at an infiltration rate of 50 in/hr. • Supplemental lab testing conducted in September 2009 using Sil-Co-Sil 106 showed an average removal of 90.6%. These laboratory tests were run at infiltration rates ranging from 25 to 150 in/hr for influent concentrations ranging from 41.6 to 252.5 mg/L. Regression analysis results indicate that the Filterra system’s TSS removal performance is independent of influent concentration in the concentration rage evaluated at hydraulic loading rates of up to 150 in/hr. Other Filterra Related Issues to be Addressed by the Company: 1. Conduct hydraulic testing on a standard precast Filterra or Filterra Bioscape at one site in the Pacific Northwest as outlined in the 2024 TAPE Guidance Document to obtain additional information about the maintenance longevity and requirements. Complete testing by February 28, 2028. Technology Description: https://www.conteches.com/stormwater-management/biofiltration- solutions/filterra/ Contact Information: Applicant: Jeremiah Lehman 11 Contech Engineered Solutions, LLC. 12901 SE 97th Ave, Suite 400 Clackamas, OR 97015 (503) 258-3136 jlehman@conteches.com Applicant’s Website: http://www.conteches.com Ecology web link: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/index.html Ecology: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 870-0983 douglas.howie@ecy.wa.gov Date Revision December 2009 GULD for Basic, Enhanced, and Oil granted, CULD for Phosphorus September 2011 Extended CULD for Phosphorus Treatment September 2012 Revised design storm discussion, added Shallow System. January 2013 Revised format to match Ecology standards, changed Filterra contact information February 2013 Added FTIB-P system March 2013 Added FTIB-C system April 2013 Modified requirements for identifying appropriate size of unit June 2013 Modified description of FTIB-C alternate configuration March 2014 GULD awarded for Phosphorus Treatment. GULD updated for a higher flow-rate for Basic Treatment. June 2014 Revised sizing calculation methods March 2015 Revised Contact Information June 2015 CULD for Basic and Enhanced at 100 in/hr infiltration rate September 2019 GULD for Basic and Enhanced at 175 in/hr infiltration rate February 2020 Revised sizing language to note sizing based on off-line calculations June 2020 Added Phosphorus to Filterra Shallow sizing table January 2024 Revised Dissolved Metals (Enhanced) to Metals July 2024 GULD for Basic, Enhanced, and Phosphorus at 324 in/hr infiltration rate for vegetated and unvegetated Filterra systems. Updated Contech address March 2025 Added requirement for maintenance assessment April 2025 Updated Findings of Fact for Field Testing 2021-2023 Technical Information Report New Renton High School Project No. 2230388.10 Appendix E Conveyance Calculations E-1 .................... Phase 1 Conveyance E-2 .................... Phase 2 Conveyance (to be included in a future submittal) SD 1-63A SD 1-64A SD 1-65A SD 1-66A SD 1-67A SD 1-68ASD 1-68BSD 1-69A SD 1-70 SD 1-72A SD 1-71 STCB#7092STCB#7093 SD 1-77A SD 1-57SD 1-58SD 1-59SD 1-60SD 1-61 SD 1-44 SD 1-47SD 1-48SD 1-49SD 1-51SD 1-52SD 1-54SD 1-56 TRENCH DRAIN A ROOF AREA TO SD 1-72A FUTURE ROOF AREA TO SD 1-71 ROOF AREA TO STCB#7092 ROOF AREA TO STCB#7093ROOF AREA TO SD 1-77A TRENCH DRAIN B TRENCH DRAIN C BASIN TD-C 0.31 AC 95% IMPERVIOUS BASIN 1-56 0.31 AC 95% IMPERVIOUS BASIN TD-B 0.13 AC 95% IMPERV BASIN 1-54 0.31 AC 95% IMPERV BASIN 1-52 0.32 AC 95% IMPERV BASIN 1-51 0.30 AC 95% IMPERV BASIN 1-49 0.25 AC 95% IMPERV BASIN 1-48 0.24 AC 95% IMPERV BASIN 1-47 0.34 AC 95% IMPERV BASIN 1-44 0.14 AC 95% IMPERV BASIN 1-61 0.16 AC 95% IMPERVIOUS BASIN 1-60 0.13 AC 95% IMPERVIOUS BASIN 1-59 0.16 AC 95% IMPERVIOUS BASIN 1-58 0.15 AC 95% IMPERVIOUS BASIN 1-57 0.22 AC 95% IMPERVIOUS BASIN 1-70 0.23 AC 40% IMPERVIOUS BASIN 1-69A 0.06 AC 95% IMPERV BASIN 1-68B 0.08 AC 95% IMPERV BASIN 1-68A 0.11 AC 95% IMPERV BASIN 1-67A 0.04 AC 95% IMPERV BASIN 1-66A 0.20 AC 80% IMPERVIOUS BASIN 1-65A 0.04 AC 95% IMPERV BASIN 1-64A 0.36 AC 80% IMPERVIOUS BASIN 1-63A 0.07 AC 95% IMPERV BASIN TD-A 0.22 AC 80% IMPERVIOUS BASIN 1-77A 0.19 AC 100% IMPERVIOUS BASIN 7093 0.29 AC 100% IMPERVIOUS BASIN 7092 0.15 AC 100% IMPERV BASIN 1-72A 0.14 AC 100% IMPERV BASIN 1-71 1.62 AC 100% IMPERV SD 1-1 FUTURE FIELD AREA TO SD 1-1 BASIN 1-1 3.38 AC 100% IMPERV 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL CONVEYANCE BASINS PHASE 1 E-1 2230388.10 12/9/2025 N GRAPHIC SCALE 0 50 100 1" = 50 FEET 25 Autodesk® Storm and Sanitary Analysis 2024 - Version 13.6.323 (Build 0) ----------------------------------------------------------------------------------------- ******************* Project Description ******************* File Name ................. RHS-Phase 1.SPF Description ............... Q:\2023\2230388\10_CIV\CAD\_2230388-W-STRM_P1.dwg **************** Analysis Options **************** Flow Units ................ cfs Subbasin Hydrograph Method. Santa Barbara UH Time of Concentration...... SCS TR-55 Link Routing Method ....... Hydrodynamic Storage Node Exfiltration.. None Starting Date ............. DEC-11-2025 00:00:00 Ending Date ............... DEC-12-2025 00:00:00 Report Time Step .......... 00:00:10 ************* Element Count ************* Number of rain gages ...... 1 Number of subbasins ....... 31 Number of nodes ........... 58 Number of links ........... 54 **************** Raingage Summary **************** Gage Data Data Recording ID Source Type Interval min APPENDIX E-1 ------------------------------------------------------------ Renton City of Renton CUMULATIVE 6.00 **************** Subbasin Summary **************** Subbasin Total Imperv. Raingage Area Area ID acres % ---------------------------------------------------- 1-1 3.38 100.00 Renton 1-44 0.14 95.00 Renton 1-47 0.34 95.00 Renton 1-48 0.24 95.00 Renton 1-49 0.25 95.00 Renton 1-51 0.30 95.00 Renton 1-52 0.32 95.00 Renton 1-54 0.31 95.00 Renton 1-56 0.31 95.00 Renton 1-57 0.22 95.00 Renton 1-58 0.15 95.00 Renton 1-59 0.16 95.00 Renton 1-60 0.13 95.00 Renton 1-61 0.16 95.00 Renton 1-63A 0.07 95.00 Renton 1-64A 0.36 80.00 Renton 1-65A 0.04 95.00 Renton 1-66A 0.20 80.00 Renton 1-67A 0.04 95.00 Renton 1-68A 0.11 95.00 Renton 1-68B 0.08 95.00 Renton 1-69A 0.06 95.00 Renton 1-70 0.23 40.00 Renton 1-71 1.62 100.00 Renton 1-72A 0.14 100.00 Renton 1-77A 0.19 100.00 Renton 7092 0.15 100.00 Renton 7093 0.29 100.00 Renton APPENDIX E-1 TD-A 0.22 80.00 Renton TD-B 0.13 95.00 Renton TD-C 0.31 95.00 Renton ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow ft ft ft² ------------------------------------------------------------------------------ BIOPOD 5 JUNCTION 22.83 27.80 0.00 SD 1-1 JUNCTION 25.05 27.52 0.00 SD 1-2 (STORM _P1) JUNCTION 21.73 27.33 0.00 SD 1-3 (STORM _P1) JUNCTION 23.53 28.51 0.00 SD 1-4 (STORM _P1) JUNCTION 22.00 32.18 0.00 SD 1-44 JUNCTION 30.08 33.12 0.00 SD 1-45 JUNCTION 31.07 33.44 0.00 SD 1-46 (STORM _P1) JUNCTION 29.73 32.86 0.00 SD 1-47 (STORM _P1) JUNCTION 29.39 32.51 0.00 SD 1-48 (STORM _P1) JUNCTION 29.02 32.51 0.00 SD 1-49 (STORM _P1) JUNCTION 28.60 32.51 0.00 SD 1-50 (STORM _P1) JUNCTION 28.21 32.55 0.00 SD 1-51 (STORM _P1) JUNCTION 28.14 32.55 0.00 SD 1-52 (STORM _P1) JUNCTION 27.76 32.51 0.00 SD 1-53 (STORM _P1) JUNCTION 27.60 32.73 0.00 SD 1-54 (STORM _P1) JUNCTION 27.34 32.51 0.00 SD 1-55 (STORM _P1) JUNCTION 27.05 32.64 0.00 SD 1-56 (STORM _P1) JUNCTION 27.32 32.49 0.00 SD 1-57 (STORM _P1) JUNCTION 29.87 32.88 0.00 SD 1-58 (STORM _P1) JUNCTION 29.33 32.87 0.00 SD 1-59 (STORM _P1) JUNCTION 28.96 32.87 0.00 SD 1-60 (STORM _P1) JUNCTION 29.41 32.87 0.00 SD 1-61 (STORM _P1) JUNCTION 29.85 32.87 0.00 SD 1-62 (STORM _P1) JUNCTION 32.97 34.75 0.00 SD 1-63 (STORM _P1) JUNCTION 32.46 34.84 0.00 SD 1-63A (STORM _P1)JUNCTION 32.56 34.69 0.00 SD 1-64 (STORM _P1) JUNCTION 31.74 33.51 0.00 APPENDIX E-1 SD 1-64A (STORM _P1)JUNCTION 31.95 33.14 0.00 SD 1-65 (STORM _P1) JUNCTION 31.27 34.11 0.00 SD 1-65A (STORM _P1)JUNCTION 31.37 33.43 0.00 SD 1-66 (STORM _P1) JUNCTION 30.84 34.28 0.00 SD 1-66A (STORM _P1)JUNCTION 30.94 32.78 0.00 SD 1-67 (STORM _P1) JUNCTION 30.42 33.36 0.00 SD 1-67A (STORM _P1)JUNCTION 30.52 33.12 0.00 SD 1-68 (STORM _P1) JUNCTION 29.70 32.48 0.00 SD 1-68A (STORM _P1)JUNCTION 29.88 32.35 0.00 SD 1-68B (STORM _P1)JUNCTION 29.88 32.12 0.00 SD 1-69 (STORM _P1) JUNCTION 29.10 32.65 0.00 SD 1-69A (STORM _P1)JUNCTION 29.20 32.23 0.00 SD 1-70 (STORM _P1) JUNCTION 28.72 31.36 0.00 SD 1-71 JUNCTION 29.10 35.51 0.00 SD 1-72 JUNCTION 28.68 35.44 0.00 SD 1-72A JUNCTION 31.45 36.24 0.00 SD 1-73 JUNCTION 28.14 34.45 0.00 SD 1-74 JUNCTION 27.86 34.04 0.00 SD 1-75 JUNCTION 26.33 33.24 0.00 SD 1-77 JUNCTION 26.50 33.63 0.00 SD 1-77A JUNCTION 29.77 34.45 0.00 SD 1-78 (STORM _P1) JUNCTION 24.10 33.77 0.00 STCB#7092 (STORM _P1)JUNCTION 31.01 35.21 0.00 STCB#7093 (STORM _P1)JUNCTION 31.58 33.30 0.00 Trench Drain A JUNCTION 33.13 34.47 0.00 Trench Drain B JUNCTION 30.45 31.78 0.00 Trench Drain C JUNCTION 0.00 27.84 0.00 BIOPOD 1 OUTFALL 25.94 29.42 0.00 BIOPOD 6 OUTFALL 25.66 29.42 0.00 SD 1-15 OUTFALL 25.50 27.00 0.00 STCB#508 (STORM _P1)OUTFALL 21.56 23.56 0.00 ************ Link Summary ************ Link From Node To Node Element Length Slope Manning's ID Type ft % Roughness -------------------------------------------------------------------------------------------- APPENDIX E-1 {STORM _P1}.1-2 to 508SD 1-2 (STORM _P1)STCB#508 (STORM _P1)CONDUIT 26.0 0.6538 0.0130 {STORM _P1}.1-3 to 1-2SD 1-3 (STORM _P1)SD 1-2 (STORM _P1)CONDUIT 54.0 3.2778 0.0130 {STORM _P1}.1-4 to 1-3SD 1-4 (STORM _P1)SD 1-3 (STORM _P1)CONDUIT 205.6 0.7296 0.0130 {STORM _P1}.1-44 to 1-45SD 1-44 SD 1-45 CONDUIT 21.0 0.5238 0.0130 {STORM _P1}.1-46 to 1-47SD 1-46 (STORM _P1)SD 1-47 (STORM _P1)CONDUIT 28.1 0.4985 0.0130 {STORM _P1}.1-47 to 1-48SD 1-47 (STORM _P1)SD 1-48 (STORM _P1)CONDUIT 61.4 0.5051 0.0130 {STORM _P1}.1-48 to 1-49SD 1-48 (STORM _P1)SD 1-49 (STORM _P1)CONDUIT 70.0 0.5000 0.0130 {STORM _P1}.1-49 to 1-50SD 1-49 (STORM _P1)SD 1-50 (STORM _P1)CONDUIT 65.5 0.5034 0.0130 {STORM _P1}.1-50 to 1-51SD 1-50 (STORM _P1)SD 1-51 (STORM _P1)CONDUIT 11.2 0.5376 0.0130 {STORM _P1}.1-51 to 1-52SD 1-51 (STORM _P1)SD 1-52 (STORM _P1)CONDUIT 63.3 0.5055 0.0130 {STORM _P1}.1-52 to 1-53SD 1-52 (STORM _P1)SD 1-53 (STORM _P1)CONDUIT 26.7 0.4869 0.0130 {STORM _P1}.1-53 to 1-54SD 1-53 (STORM _P1)SD 1-54 (STORM _P1)CONDUIT 43.3 0.5080 0.0130 {STORM _P1}.1-54 to 1-55SD 1-54 (STORM _P1)SD 1-55 (STORM _P1)CONDUIT 41.0 0.5122 0.0130 {STORM _P1}.1-55 to Filterra 6SD 1-55 (STORM _P1)BIOPOD 6 CONDUIT 43.0 0.4879 0.0130 {STORM _P1}.1-56 to 1-55SD 1-56 (STORM _P1)SD 1-55 (STORM _P1)CONDUIT 19.0 0.5789 0.0130 {STORM _P1}.1-57 to 1-58SD 1-57 (STORM _P1)SD 1-58 (STORM _P1)CONDUIT 89.7 0.5998 0.0130 {STORM _P1}.1-58 to 1-59SD 1-58 (STORM _P1)SD 1-59 (STORM _P1)CONDUIT 94.0 1.4569 0.0130 {STORM _P1}.1-60 to 1-59SD 1-60 (STORM _P1)SD 1-59 (STORM _P1)CONDUIT 89.3 0.5040 0.0130 {STORM _P1}.1-61 to 1-60SD 1-61 (STORM _P1)SD 1-60 (STORM _P1)CONDUIT 88.9 0.4948 0.0130 {STORM _P1}.1-62 to 1-63SD 1-62 (STORM _P1)SD 1-63 (STORM _P1)CONDUIT 85.0 0.6000 0.0130 {STORM _P1}.1-63 to 1-64SD 1-63 (STORM _P1)SD 1-64 (STORM _P1)CONDUIT 120.0 0.6000 0.0130 {STORM _P1}.1-63A to 1-63SD 1-63A (STORM _P1)SD 1-63 (STORM _P1)CONDUIT 16.0 0.6250 0.0130 {STORM _P1}.1-64 to 1-65SD 1-64 (STORM _P1)SD 1-65 (STORM _P1)CONDUIT 78.0 0.6026 0.0130 {STORM _P1}.1-64A to 1-64SD 1-64A (STORM _P1)SD 1-64 (STORM _P1)CONDUIT 16.0 1.3125 0.0130 {STORM _P1}.1-65 to 1-66SD 1-65 (STORM _P1)SD 1-66 (STORM _P1)CONDUIT 72.0 0.5972 0.0130 {STORM _P1}.1-65A to 1-65SD 1-65A (STORM _P1)SD 1-65 (STORM _P1)CONDUIT 17.0 0.5882 0.0130 {STORM _P1}.1-66 to 1-67SD 1-66 (STORM _P1)SD 1-67 (STORM _P1)CONDUIT 69.0 0.6087 0.0130 {STORM _P1}.1-66A to 1-66SD 1-66A (STORM _P1)SD 1-66 (STORM _P1)CONDUIT 16.0 0.6250 0.0130 {STORM _P1}.1-67A to 1-67SD 1-67A (STORM _P1)SD 1-67 (STORM _P1)CONDUIT 16.0 0.6250 0.0130 {STORM _P1}.1-68A to 1-68SD 1-68A (STORM _P1)SD 1-68 (STORM _P1)CONDUIT 26.0 0.6923 0.0130 {STORM _P1}.1-68B to 1-68SD 1-68B (STORM _P1)SD 1-68 (STORM _P1)CONDUIT 16.0 1.1250 0.0130 {STORM _P1}.1-69A to 1-69SD 1-69A (STORM _P1)SD 1-69 (STORM _P1)CONDUIT 16.0 0.6250 0.0130 {STORM _P1}.1-70 to Filterra 1SD 1-70 (STORM _P1)BIOPOD 1 CONDUIT 15.0 2.0000 0.0130 {STORM _P1}.1-72 to 1-73SD 1-71 SD 1-72 CONDUIT 69.3 0.6061 0.0130 {STORM _P1}.1-73 to 1-74SD 1-72 SD 1-73 CONDUIT 89.2 0.6055 0.0130 {STORM _P1}.1-74 to 1-75SD 1-73 SD 1-74 CONDUIT 46.0 0.6093 0.0130 {STORM _P1}.1-75 to 1-76SD 1-74 SD 1-75 CONDUIT 255.0 0.6000 0.0130 {STORM _P1}.1-75 to 1-78SD 1-75 SD 1-78 (STORM _P1)CONDUIT 38.0 0.6053 0.0130 {STORM _P1}.SD 1-77A to 1-77SD 1-77 SD 1-77A CONDUIT 16.0 16.3812 0.0130 APPENDIX E-1 {STORM _P1}.SD 86 (STORM _P1)SD 1-72A SD 1-72 CONDUIT 24.3 1.8344 0.0130 {STORM _P1}.SD 87 (STORM _P1)STCB#7092 (STORM _P1)SD 1-73 CONDUIT 32.6 2.9961 0.0130 {STORM _P1}.SD 88 (STORM _P1)STCB#7093 (STORM _P1)SD 1-74 CONDUIT 33.7 2.8831 0.0130 {STORM _P1}.SD 89 (STORM _P1)SD 1-77 SD 1-78 (STORM _P1)CONDUIT 66.0 0.6061 0.0130 {STORM _P1}.SD 97 (STORM _P1)SD 1-67 (STORM _P1)SD 1-68 (STORM _P1)CONDUIT 120.0 0.6000 0.0130 {STORM _P1}.SD 98 (STORM _P1)SD 1-68 (STORM _P1)SD 1-69 (STORM _P1)CONDUIT 100.0 0.6000 0.0130 {STORM _P1}.SD 99 (STORM _P1)SD 1-69 (STORM _P1)SD 1-70 (STORM _P1)CONDUIT 63.0 0.6032 0.0130 {STORM _P1}.TD-A to 1-62Trench Drain A SD 1-62 (STORM _P1)CONDUIT 16.0 1.0000 0.0130 {STORM _P1}.TD-C to 1.1Trench Drain C SD 1-1 CONDUIT 46.0 1.7174 0.0130 1-45 to 1-46 SD 1-45 SD 1-46 (STORM _P1)CONDUIT 73.0 0.5068 0.0150 1-59 to 1-70 SD 1-59 (STORM _P1)SD 1-70 (STORM _P1)CONDUIT 47.0 0.5106 0.0150 BIOPOD 5 to 1-2 BIOPOD 5 SD 1-2 (STORM _P1)CONDUIT 5.0 2.0000 0.0150 Link-03 SD 1-1 BIOPOD 5 CONDUIT 5.0 1.0000 0.0150 Link-04 Trench Drain B SD 1-61 (STORM _P1)CONDUIT 60.0 1.0000 0.0150 SD 1-78 to 1-15 SD 1-78 (STORM _P1)SD 1-15 CONDUIT 17.0 0.5882 0.0150 ********************* Cross Section Summary ********************* Link Shape Depth/ Width No. of Cross Full Flow Design ID Diameter Barrels Sectional Hydraulic Flow Area Radius Capacity ft ft ft² ft cfs ---------------------------------------------------------------------------------------------------------- {STORM _P1}.1-2 to 508 CIRCULAR 1.00 1.00 1 0.79 0.25 2.88 {STORM _P1}.1-3 to 1-2 CIRCULAR 1.00 1.00 1 0.79 0.25 6.45 {STORM _P1}.1-4 to 1-3 CIRCULAR 1.00 1.00 1 0.79 0.25 3.04 {STORM _P1}.1-44 to 1-45 CIRCULAR 1.00 1.00 1 0.79 0.25 2.58 {STORM _P1}.1-46 to 1-47 CIRCULAR 1.00 1.00 1 0.79 0.25 2.52 {STORM _P1}.1-47 to 1-48 CIRCULAR 1.00 1.00 1 0.79 0.25 2.53 {STORM _P1}.1-48 to 1-49 CIRCULAR 1.00 1.00 1 0.79 0.25 2.52 {STORM _P1}.1-49 to 1-50 CIRCULAR 1.00 1.00 1 0.79 0.25 2.53 {STORM _P1}.1-50 to 1-51 CIRCULAR 1.00 1.00 1 0.79 0.25 2.61 {STORM _P1}.1-51 to 1-52 CIRCULAR 1.00 1.00 1 0.79 0.25 2.53 {STORM _P1}.1-52 to 1-53 CIRCULAR 1.00 1.00 1 0.79 0.25 2.49 {STORM _P1}.1-53 to 1-54 CIRCULAR 1.00 1.00 1 0.79 0.25 2.54 {STORM _P1}.1-54 to 1-55 CIRCULAR 1.00 1.00 1 0.79 0.25 2.55 {STORM _P1}.1-55 to Filterra 6 CIRCULAR 1.00 1.00 1 0.79 0.25 APPENDIX E-1 2.49 {STORM _P1}.1-56 to 1-55 CIRCULAR 1.00 1.00 1 0.79 0.25 2.71 {STORM _P1}.1-57 to 1-58 CIRCULAR 1.00 1.00 1 0.79 0.25 2.76 {STORM _P1}.1-58 to 1-59 CIRCULAR 1.00 1.00 1 0.79 0.25 4.30 {STORM _P1}.1-60 to 1-59 CIRCULAR 1.00 1.00 1 0.79 0.25 2.53 {STORM _P1}.1-61 to 1-60 CIRCULAR 1.00 1.00 1 0.79 0.25 2.51 {STORM _P1}.1-62 to 1-63 CIRCULAR 1.00 1.00 1 0.79 0.25 2.76 {STORM _P1}.1-63 to 1-64 CIRCULAR 1.00 1.00 1 0.79 0.25 2.76 {STORM _P1}.1-63A to 1-63 CIRCULAR 1.00 1.00 1 0.79 0.25 2.82 {STORM _P1}.1-64 to 1-65 CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.1-64A to 1-64 CIRCULAR 1.00 1.00 1 0.79 0.25 4.08 {STORM _P1}.1-65 to 1-66 CIRCULAR 1.00 1.00 1 0.79 0.25 2.75 {STORM _P1}.1-65A to 1-65 CIRCULAR 1.00 1.00 1 0.79 0.25 2.73 {STORM _P1}.1-66 to 1-67 CIRCULAR 1.00 1.00 1 0.79 0.25 2.78 {STORM _P1}.1-66A to 1-66 CIRCULAR 1.00 1.00 1 0.79 0.25 2.82 {STORM _P1}.1-67A to 1-67 CIRCULAR 1.00 1.00 1 0.79 0.25 2.82 {STORM _P1}.1-68A to 1-68 CIRCULAR 1.00 1.00 1 0.79 0.25 2.96 {STORM _P1}.1-68B to 1-68 CIRCULAR 1.00 1.00 1 0.79 0.25 3.78 {STORM _P1}.1-69A to 1-69 CIRCULAR 1.00 1.00 1 0.79 0.25 2.82 {STORM _P1}.1-70 to Filterra 1 CIRCULAR 1.00 1.00 1 0.79 0.25 5.04 {STORM _P1}.1-72 to 1-73 CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.1-73 to 1-74 CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.1-74 to 1-75 CIRCULAR 1.00 1.00 1 0.79 0.25 2.78 {STORM _P1}.1-75 to 1-76 CIRCULAR 1.00 1.00 1 0.79 0.25 2.76 {STORM _P1}.1-75 to 1-78 CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.SD 1-77A to 1-77 CIRCULAR 0.50 0.50 1 0.20 0.13 2.27 {STORM _P1}.SD 86 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 4.83 {STORM _P1}.SD 87 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 6.17 {STORM _P1}.SD 88 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 6.05 {STORM _P1}.SD 89 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.SD 97 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 2.76 {STORM _P1}.SD 98 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 APPENDIX E-1 2.76 {STORM _P1}.SD 99 (STORM _P1) CIRCULAR 1.00 1.00 1 0.79 0.25 2.77 {STORM _P1}.TD-A to 1-62 CIRCULAR 0.33 0.33 1 0.09 0.08 0.19 {STORM _P1}.TD-C to 1.1 CIRCULAR 0.50 0.50 1 0.20 0.13 0.74 1-45 to 1-46 CIRCULAR 1.00 1.00 1 0.79 0.25 2.20 1-59 to 1-70 CIRCULAR 1.00 1.00 1 0.79 0.25 2.21 BIOPOD 5 to 1-2 CIRCULAR 1.00 1.00 1 0.79 0.25 4.37 Link-03 CIRCULAR 1.00 1.00 1 0.79 0.25 3.09 Link-04 CIRCULAR 0.33 0.33 1 0.09 0.08 0.16 SD 1-78 to 1-15 CIRCULAR 1.00 1.00 1 0.79 0.25 2.37 ************************** Volume Depth Runoff Quantity Continuity acre-ft inches ************************** --------- ------- Total Precipitation ...... 2.923 3.294 Surface Runoff ........... 2.639 2.973 Continuity Error (%) ..... 0.000 ************************** Volume Volume Flow Routing Continuity acre-ft Mgallons ************************** --------- --------- External Inflow .......... 0.043 0.014 External Outflow ......... 2.635 0.859 Initial Stored Volume .... 0.001 0.000 Final Stored Volume ...... 0.023 0.007 Continuity Error (%) ..... 0.009 ****************************************** Composite Curve Number Computations Report ****************************************** --------------- Subbasin 1-1 --------------- Area Soil APPENDIX E-1 Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 3.38 98.00 ---------------- Subbasin 1-44 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.14 96.90 ---------------- Subbasin 1-47 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.34 96.90 ---------------- Subbasin 1-48 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.24 96.90 ---------------- Subbasin 1-49 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.25 96.90 ---------------- Subbasin 1-51 ---------------- APPENDIX E-1 Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.30 96.90 ---------------- Subbasin 1-52 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.32 96.90 ---------------- Subbasin 1-54 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.31 96.90 ---------------- Subbasin 1-56 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.31 96.90 ---------------- Subbasin 1-57 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.22 96.90 ---------------- Subbasin 1-58 APPENDIX E-1 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.15 96.90 ---------------- Subbasin 1-59 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.16 96.90 ---------------- Subbasin 1-60 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.13 96.90 ---------------- Subbasin 1-61 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.16 96.90 ----------------- Subbasin 1-63A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.07 96.90 ----------------- APPENDIX E-1 Subbasin 1-64A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.36 93.60 ----------------- Subbasin 1-65A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.04 96.90 ----------------- Subbasin 1-66A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.20 93.60 ----------------- Subbasin 1-67A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.04 96.90 ----------------- Subbasin 1-68A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.11 96.90 APPENDIX E-1 ----------------- Subbasin 1-68B ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.08 96.90 ----------------- Subbasin 1-69A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.06 96.90 ---------------- Subbasin 1-70 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.23 84.80 ---------------- Subbasin 1-71 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 1.62 98.00 ----------------- Subbasin 1-72A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.14 98.00 APPENDIX E-1 ----------------- Subbasin 1-77A ----------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.19 98.00 ---------------- Subbasin 7092 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.15 98.00 ---------------- Subbasin 7093 ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.29 98.00 ---------------- Subbasin TD-A ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.22 93.60 ---------------- Subbasin TD-B ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- APPENDIX E-1 Composite Area & Weighted CN 0.13 96.90 ---------------- Subbasin TD-C ---------------- Area Soil Soil/Surface Description (acres) Group CN ---------------------------------------------------------------------------------------- Composite Area & Weighted CN 0.31 96.90 ************************************** Runoff Coefficient Computations Report ************************************** --------------- Subbasin 1-1 --------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 3.38 - 0.72 Composite Area & Weighted Runoff Coeff. 3.38 0.72 ---------------- Subbasin 1-44 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.14 - 0.72 Composite Area & Weighted Runoff Coeff. 0.14 0.72 ---------------- Subbasin 1-47 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.34 - 0.72 APPENDIX E-1 Composite Area & Weighted Runoff Coeff. 0.34 0.72 ---------------- Subbasin 1-48 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.24 - 0.72 Composite Area & Weighted Runoff Coeff. 0.24 0.72 ---------------- Subbasin 1-49 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.25 - 0.72 Composite Area & Weighted Runoff Coeff. 0.25 0.72 ---------------- Subbasin 1-51 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.30 - 0.72 Composite Area & Weighted Runoff Coeff. 0.30 0.72 ---------------- Subbasin 1-52 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.32 - 0.72 Composite Area & Weighted Runoff Coeff. 0.32 0.72 ---------------- APPENDIX E-1 Subbasin 1-54 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.31 - 0.72 Composite Area & Weighted Runoff Coeff. 0.31 0.72 ---------------- Subbasin 1-56 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.31 - 0.72 Composite Area & Weighted Runoff Coeff. 0.31 0.72 ---------------- Subbasin 1-57 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.22 - 0.72 Composite Area & Weighted Runoff Coeff. 0.22 0.72 ---------------- Subbasin 1-58 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.15 - 0.72 Composite Area & Weighted Runoff Coeff. 0.15 0.72 ---------------- Subbasin 1-59 ---------------- Area Soil Runoff APPENDIX E-1 Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.16 - 0.72 Composite Area & Weighted Runoff Coeff. 0.16 0.72 ---------------- Subbasin 1-60 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.13 - 0.72 Composite Area & Weighted Runoff Coeff. 0.13 0.72 ---------------- Subbasin 1-61 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.16 - 0.72 Composite Area & Weighted Runoff Coeff. 0.16 0.72 ----------------- Subbasin 1-63A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.07 - 0.72 Composite Area & Weighted Runoff Coeff. 0.07 0.72 ----------------- Subbasin 1-64A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.36 - 0.72 APPENDIX E-1 Composite Area & Weighted Runoff Coeff. 0.36 0.72 ----------------- Subbasin 1-65A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.04 - 0.72 Composite Area & Weighted Runoff Coeff. 0.04 0.72 ----------------- Subbasin 1-66A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.20 - 0.72 Composite Area & Weighted Runoff Coeff. 0.20 0.72 ----------------- Subbasin 1-67A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.04 - 0.72 Composite Area & Weighted Runoff Coeff. 0.04 0.72 ----------------- Subbasin 1-68A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.11 - 0.72 Composite Area & Weighted Runoff Coeff. 0.11 0.72 ----------------- APPENDIX E-1 Subbasin 1-68B ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.08 - 0.72 Composite Area & Weighted Runoff Coeff. 0.08 0.72 ----------------- Subbasin 1-69A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.06 - 0.72 Composite Area & Weighted Runoff Coeff. 0.06 0.72 ---------------- Subbasin 1-70 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.23 - 0.72 Composite Area & Weighted Runoff Coeff. 0.23 0.72 ---------------- Subbasin 1-71 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 1.62 - 0.72 Composite Area & Weighted Runoff Coeff. 1.62 0.72 ----------------- Subbasin 1-72A ----------------- Area Soil Runoff APPENDIX E-1 Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.14 - 0.72 Composite Area & Weighted Runoff Coeff. 0.14 0.72 ----------------- Subbasin 1-77A ----------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.19 - 0.72 Composite Area & Weighted Runoff Coeff. 0.19 0.72 ---------------- Subbasin 7092 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.15 - 0.72 Composite Area & Weighted Runoff Coeff. 0.15 0.72 ---------------- Subbasin 7093 ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.29 - 0.72 Composite Area & Weighted Runoff Coeff. 0.29 0.72 ---------------- Subbasin TD-A ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.22 - 0.72 APPENDIX E-1 Composite Area & Weighted Runoff Coeff. 0.22 0.72 ---------------- Subbasin TD-B ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.13 - 0.72 Composite Area & Weighted Runoff Coeff. 0.13 0.72 ---------------- Subbasin TD-C ---------------- Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ----------------------------------------------------------------------------------------- - 0.31 - 0.72 Composite Area & Weighted Runoff Coeff. 0.31 0.72 *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation ------------------- Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation APPENDIX E-1 ---------------------------------- V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation --------------------- V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness --------------- Subbasin 1-1 APPENDIX E-1 --------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-44 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-47 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-48 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-49 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- APPENDIX E-1 Subbasin 1-51 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-52 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-54 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-56 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-57 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ APPENDIX E-1 ---------------- Subbasin 1-58 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-59 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-60 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-61 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-63A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ APPENDIX E-1 ----------------- Subbasin 1-64A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-65A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-66A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-67A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-68A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ APPENDIX E-1 ----------------- Subbasin 1-68B ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-69A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-70 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 1-71 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ----------------- Subbasin 1-72A ----------------- ================================================================================================ Total TOC (minutes): 0.00 APPENDIX E-1 ================================================================================================ ----------------- Subbasin 1-77A ----------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 7092 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin 7093 ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin TD-A ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin TD-B ---------------- ================================================================================================ APPENDIX E-1 Total TOC (minutes): 0.00 ================================================================================================ ---------------- Subbasin TD-C ---------------- ================================================================================================ Total TOC (minutes): 0.00 ================================================================================================ *********************** Subbasin Runoff Summary *********************** -------------------------------------------------------------------------- Subbasin Total Total Peak Weighted Time of ID Precip Runoff Runoff Curve Concentration in in cfs Number days hh:mm:ss -------------------------------------------------------------------------- 1-1 3.29 3.06 2.57 98.000 0 00:06:00 1-44 3.29 2.97 0.10 96.900 0 00:06:00 1-47 3.29 2.97 0.25 96.900 0 00:06:00 1-48 3.29 2.97 0.18 96.900 0 00:06:00 1-49 3.29 2.97 0.18 96.900 0 00:06:00 1-51 3.29 2.97 0.22 96.900 0 00:06:00 1-52 3.29 2.97 0.23 96.900 0 00:06:00 1-54 3.29 2.97 0.23 96.900 0 00:06:00 1-56 3.29 2.97 0.23 96.900 0 00:06:00 1-57 3.29 2.97 0.16 96.900 0 00:06:00 1-58 3.29 2.97 0.11 96.900 0 00:06:00 1-59 3.29 2.97 0.12 96.900 0 00:06:00 1-60 3.29 2.97 0.10 96.900 0 00:06:00 1-61 3.29 2.97 0.12 96.900 0 00:06:00 1-63A 3.29 2.97 0.05 96.900 0 00:06:00 1-64A 3.29 2.69 0.24 93.600 0 00:06:00 1-65A 3.29 2.97 0.03 96.900 0 00:06:00 1-66A 3.29 2.69 0.13 93.600 0 00:06:00 APPENDIX E-1 1-67A 3.29 2.97 0.03 96.900 0 00:06:00 1-68A 3.29 2.97 0.08 96.900 0 00:06:00 1-68B 3.29 2.97 0.06 96.900 0 00:06:00 1-69A 3.29 2.97 0.04 96.900 0 00:06:00 1-70 3.29 1.95 0.10 84.800 0 00:06:00 1-71 3.29 3.06 1.23 98.000 0 00:06:00 1-72A 3.29 3.06 0.11 98.000 0 00:06:00 1-77A 3.29 3.06 0.14 98.000 0 00:06:00 7092 3.29 3.06 0.11 98.000 0 00:06:00 7093 3.29 3.06 0.22 98.000 0 00:06:00 TD-A 3.29 2.69 0.14 93.600 0 00:06:00 TD-B 3.29 2.97 0.10 96.900 0 00:06:00 TD-C 3.29 2.97 0.23 96.900 0 00:06:00 -------------------------------------------------------------------------- ****************** Node Depth Summary ****************** ----------------------------------------------------------------------------------------- Node Average Maximum Maximum Time of Max Total Total Retention ID Depth Depth HGL Occurrence Flooded Time Time Attained Attained Attained Volume Flooded ft ft ft days hh:mm acre-in minutes hh:mm:ss ----------------------------------------------------------------------------------------- BIOPOD 5 0.47 1.16 23.99 0 07:54 0 0 0:00:00 SD 1-1 0.34 1.02 26.07 0 07:54 0 0 0:00:00 SD 1-2 (STORM _P1) 1.53 2.01 23.75 0 07:54 0 0 0:00:00 SD 1-3 (STORM _P1) 0.00 0.00 23.53 0 00:00 0 0 0:00:00 SD 1-4 (STORM _P1) 0.00 0.00 22.00 0 00:00 0 0 0:00:00 SD 1-44 1.14 1.25 31.33 0 07:54 0 0 0:00:00 SD 1-45 0.07 0.15 31.22 0 08:00 0 0 0:00:00 SD 1-46 (STORM _P1) 1.00 1.11 30.84 0 07:54 0 0 0:00:00 SD 1-47 (STORM _P1) 1.26 1.43 30.82 0 07:54 0 0 0:00:00 SD 1-48 (STORM _P1) 1.35 1.56 30.58 0 08:00 0 0 0:00:00 SD 1-49 (STORM _P1) 1.46 1.92 30.52 0 08:00 0 0 0:00:00 SD 1-50 (STORM _P1) 1.82 2.28 30.48 0 08:00 0 0 0:00:00 SD 1-51 (STORM _P1) 1.89 2.33 30.47 0 08:00 0 0 0:00:00 APPENDIX E-1 SD 1-52 (STORM _P1) 2.27 2.65 30.41 0 08:00 0 0 0:00:00 SD 1-53 (STORM _P1) 2.42 2.75 30.35 0 08:00 0 0 0:00:00 SD 1-54 (STORM _P1) 2.68 2.92 30.26 0 08:00 0 0 0:00:00 SD 1-55 (STORM _P1) 2.96 3.31 30.36 0 00:00 0 0 0:00:00 SD 1-56 (STORM _P1) 2.69 3.03 30.34 0 00:00 0 0 0:00:00 SD 1-57 (STORM _P1) 1.06 1.17 31.04 0 07:54 0 0 0:00:00 SD 1-58 (STORM _P1) 1.06 1.17 30.50 0 07:55 0 0 0:00:00 SD 1-59 (STORM _P1) 1.05 1.17 30.13 0 08:00 0 0 0:00:00 SD 1-60 (STORM _P1) 0.60 0.73 30.14 0 08:00 0 0 0:00:00 SD 1-61 (STORM _P1) 0.16 0.30 30.15 0 08:00 0 0 0:00:00 SD 1-62 (STORM _P1) 0.07 0.16 33.13 0 08:00 0 0 0:00:00 SD 1-63 (STORM _P1) 0.08 0.18 32.64 0 08:00 0 0 0:00:00 SD 1-63A (STORM _P1) 0.04 0.09 32.65 0 07:58 0 0 0:00:00 SD 1-64 (STORM _P1) 0.12 0.28 32.02 0 08:00 0 0 0:00:00 SD 1-64A (STORM _P1) 0.07 0.18 32.13 0 07:54 0 0 0:00:00 SD 1-65 (STORM _P1) 0.12 0.29 31.56 0 08:00 0 0 0:00:00 SD 1-65A (STORM _P1) 0.04 0.19 31.56 0 08:00 0 0 0:00:00 SD 1-66 (STORM _P1) 0.14 0.34 31.18 0 08:00 0 0 0:00:00 SD 1-66A (STORM _P1) 0.07 0.24 31.18 0 08:00 0 0 0:00:00 SD 1-67 (STORM _P1) 0.14 0.32 30.74 0 08:00 0 0 0:00:00 SD 1-67A (STORM _P1) 0.05 0.22 30.74 0 08:00 0 0 0:00:00 SD 1-68 (STORM _P1) 0.31 0.50 30.20 0 08:00 0 0 0:00:00 SD 1-68A (STORM _P1) 0.13 0.32 30.20 0 08:00 0 0 0:00:00 SD 1-68B (STORM _P1) 0.13 0.32 30.20 0 08:00 0 0 0:00:00 SD 1-69 (STORM _P1) 0.91 1.04 30.14 0 08:00 0 0 0:00:00 SD 1-69A (STORM _P1) 0.81 0.94 30.14 0 08:00 0 0 0:00:00 SD 1-70 (STORM _P1) 1.29 2.65 31.36 0 00:00 0.00 0 0:00:00 SD 1-71 0.99 2.23 31.33 0 08:00 0 0 0:00:00 SD 1-72 1.40 2.53 31.21 0 08:00 0 0 0:00:00 SD 1-72A 0.05 0.11 31.55 0 07:51 0 0 0:00:00 SD 1-73 1.93 2.90 31.04 0 08:00 0 0 0:00:00 SD 1-74 2.20 3.06 30.92 0 08:00 0 0 0:00:00 SD 1-75 3.69 6.91 33.24 0 00:00 0.00 0 0:00:00 SD 1-77 3.51 3.76 30.26 0 00:01 0 0 0:00:00 SD 1-77A 2.64 2.87 32.64 0 07:54 0 0 0:00:00 SD 1-78 (STORM _P1) 5.91 9.67 33.77 0 00:00 0.00 0 0:00:00 STCB#7092 (STORM _P1) 1.03 1.10 32.11 0 07:54 0 0 0:00:00 STCB#7093 (STORM _P1) 0.06 0.13 31.71 0 07:47 0 0 0:00:00 Trench Drain A 0.09 0.24 33.37 0 08:00 0 0 0:00:00 APPENDIX E-1 Trench Drain B 0.07 0.18 30.63 0 07:55 0 0 0:00:00 Trench Drain C 24.25 26.53 26.53 0 07:54 0 0 0:00:00 BIOPOD 1 4.06 4.06 30.00 0 00:00 0 0 0:00:00 BIOPOD 6 4.34 4.34 30.00 0 00:00 0 0 0:00:00 SD 1-15 4.50 4.50 30.00 0 00:00 0 0 0:00:00 STCB#508 (STORM _P1) 1.67 1.72 23.28 0 07:54 0 0 0:00:00 ***************** Node Flow Summary ***************** ------------------------------------------------------------------------------------ Node Element Maximum Peak Time of Maximum Time of Peak ID Type Lateral Inflow Peak Inflow Flooding Flooding Inflow Occurrence Overflow Occurrence cfs cfs days hh:mm cfs days hh:mm ------------------------------------------------------------------------------------ BIOPOD 5 JUNCTION 0.00 2.80 0 07:54 0.00 SD 1-1 JUNCTION 2.57 2.80 0 07:54 0.00 SD 1-2 (STORM _P1) JUNCTION 0.00 2.80 0 07:54 0.00 SD 1-3 (STORM _P1) JUNCTION 0.00 0.00 0 00:00 0.00 SD 1-4 (STORM _P1) JUNCTION 0.00 0.00 0 00:00 0.00 SD 1-44 JUNCTION 0.10 0.10 0 07:54 0.00 SD 1-45 JUNCTION 0.00 0.10 0 07:54 0.00 SD 1-46 (STORM _P1) JUNCTION 0.00 0.10 0 07:55 0.00 SD 1-47 (STORM _P1) JUNCTION 0.25 0.35 0 07:55 0.00 SD 1-48 (STORM _P1) JUNCTION 0.18 0.53 0 07:55 0.00 SD 1-49 (STORM _P1) JUNCTION 0.18 0.71 0 07:58 0.00 SD 1-50 (STORM _P1) JUNCTION 0.00 0.71 0 08:01 0.00 SD 1-51 (STORM _P1) JUNCTION 0.22 0.93 0 08:00 0.00 SD 1-52 (STORM _P1) JUNCTION 0.23 1.16 0 08:00 0.00 SD 1-53 (STORM _P1) JUNCTION 0.00 1.41 0 00:01 0.00 SD 1-54 (STORM _P1) JUNCTION 0.23 2.13 0 00:00 0.00 SD 1-55 (STORM _P1) JUNCTION 0.00 3.12 0 00:00 0.00 SD 1-56 (STORM _P1) JUNCTION 0.23 1.63 0 00:00 0.00 SD 1-57 (STORM _P1) JUNCTION 0.16 0.16 0 07:54 0.00 SD 1-58 (STORM _P1) JUNCTION 0.11 0.27 0 07:55 0.00 SD 1-59 (STORM _P1) JUNCTION 0.12 1.44 0 00:01 0.00 APPENDIX E-1 SD 1-60 (STORM _P1) JUNCTION 0.10 0.77 0 00:02 0.00 SD 1-61 (STORM _P1) JUNCTION 0.12 0.21 0 07:55 0.00 SD 1-62 (STORM _P1) JUNCTION 0.00 0.14 0 08:00 0.00 SD 1-63 (STORM _P1) JUNCTION 0.00 0.20 0 08:00 0.00 SD 1-63A (STORM _P1) JUNCTION 0.05 0.05 0 07:54 0.00 SD 1-64 (STORM _P1) JUNCTION 0.00 0.43 0 08:00 0.00 SD 1-64A (STORM _P1) JUNCTION 0.24 0.24 0 08:00 0.00 SD 1-65 (STORM _P1) JUNCTION 0.00 0.46 0 08:00 0.00 SD 1-65A (STORM _P1) JUNCTION 0.03 0.03 0 07:54 0.00 SD 1-66 (STORM _P1) JUNCTION 0.00 0.59 0 08:00 0.00 SD 1-66A (STORM _P1) JUNCTION 0.13 0.13 0 08:00 0.00 SD 1-67 (STORM _P1) JUNCTION 0.00 0.62 0 08:00 0.00 SD 1-67A (STORM _P1) JUNCTION 0.03 0.03 0 07:54 0.00 SD 1-68 (STORM _P1) JUNCTION 0.00 0.76 0 08:00 0.00 SD 1-68A (STORM _P1) JUNCTION 0.08 0.08 0 07:54 0.00 SD 1-68B (STORM _P1) JUNCTION 0.06 0.06 0 07:54 0.00 SD 1-69 (STORM _P1) JUNCTION 0.00 1.16 0 00:01 0.00 SD 1-69A (STORM _P1) JUNCTION 0.04 0.51 0 00:01 0.00 SD 1-70 (STORM _P1) JUNCTION 0.10 3.57 0 00:00 1.73 0 00:00 SD 1-71 JUNCTION 1.23 1.23 0 07:54 0.00 SD 1-72 JUNCTION 0.00 1.34 0 07:54 0.00 SD 1-72A JUNCTION 0.11 0.11 0 07:54 0.00 SD 1-73 JUNCTION 0.00 1.55 0 00:02 0.00 SD 1-74 JUNCTION 0.00 2.21 0 00:02 0.00 SD 1-75 JUNCTION 0.00 5.18 0 00:00 4.13 0 00:00 SD 1-77 JUNCTION 0.00 3.53 0 00:00 0.00 SD 1-77A JUNCTION 0.14 0.14 0 07:54 0.00 SD 1-78 (STORM _P1) JUNCTION 0.00 8.21 0 00:00 4.33 0 00:00 STCB#7092 (STORM _P1) JUNCTION 0.11 0.11 0 07:54 0.00 STCB#7093 (STORM _P1) JUNCTION 0.22 0.22 0 07:54 0.00 Trench Drain A JUNCTION 0.14 0.14 0 08:00 0.00 Trench Drain B JUNCTION 0.10 0.10 0 07:54 0.00 Trench Drain C JUNCTION 0.23 0.23 0 07:54 0.00 BIOPOD 1 OUTFALL 0.00 3.57 0 00:00 0.00 BIOPOD 6 OUTFALL 0.00 3.05 0 00:00 0.00 SD 1-15 OUTFALL 0.00 8.21 0 00:00 0.00 STCB#508 (STORM _P1) OUTFALL 0.00 2.80 0 07:54 0.00 APPENDIX E-1 *********************** Outfall Loading Summary *********************** ----------------------------------------------- Outfall Node ID Flow Average Peak Frequency Flow Inflow (%) cfs cfs ----------------------------------------------- BIOPOD 1 99.96 0.32 3.57 BIOPOD 6 99.98 0.32 3.05 SD 1-15 100.00 0.36 8.21 STCB#508 (STORM _P1) 100.00 0.55 2.80 ----------------------------------------------- System 99.98 1.56 14.00 ***************** Link Flow Summary ***************** --------------------------------------------------------------------------------------------------------------------- ----------- Link ID Element Time of Maximum Length Peak Flow Design Ratio of Ratio of Total Reported Type Peak Flow Velocity Factor during Flow Maximum Maximum Time Condition Occurrence Attained Analysis Capacity /Design Flow Surcharged days hh:mm ft/sec cfs cfs Flow Depth minutes --------------------------------------------------------------------------------------------------------------------- ----------- {STORM _P1}.1-2 to 508 CONDUIT 0 07:54 3.90 1.00 2.80 2.88 0.97 0.86 0 Calculated {STORM _P1}.1-3 to 1-2 CONDUIT 0 00:00 0.00 1.00 0.00 6.45 0.00 0.50 0 Calculated {STORM _P1}.1-4 to 1-3 CONDUIT 0 00:00 0.00 1.00 0.00 3.04 0.00 0.00 0 Calculated {STORM _P1}.1-44 to 1-45 CONDUIT 0 07:54 1.39 1.00 0.10 2.58 0.04 0.15 0 Calculated APPENDIX E-1 {STORM _P1}.1-46 to 1-47 CONDUIT 0 07:55 0.95 1.00 0.10 2.52 0.04 0.20 0 Calculated {STORM _P1}.1-47 to 1-48 CONDUIT 0 07:55 1.90 1.00 0.35 2.53 0.14 0.29 0 Calculated {STORM _P1}.1-48 to 1-49 CONDUIT 0 07:59 1.83 1.00 0.53 2.52 0.21 0.47 0 Calculated {STORM _P1}.1-49 to 1-50 CONDUIT 0 08:01 1.20 1.00 0.71 2.53 0.28 0.77 0 Calculated {STORM _P1}.1-50 to 1-51 CONDUIT 0 08:01 1.62 1.00 0.72 2.61 0.27 0.94 0 Calculated {STORM _P1}.1-51 to 1-52 CONDUIT 0 08:01 1.29 1.00 0.93 2.53 0.37 0.98 0 Calculated {STORM _P1}.1-52 to 1-53 CONDUIT 0 08:00 2.09 1.00 1.16 2.49 0.47 1.00 33 SURCHARGED {STORM _P1}.1-53 to 1-54 CONDUIT 0 00:01 2.22 1.00 1.41 2.54 0.56 1.00 59 SURCHARGED {STORM _P1}.1-54 to 1-55 CONDUIT 0 00:00 3.12 1.00 2.13 2.55 0.84 1.00 1438 SURCHARGED {STORM _P1}.1-55 to Filterra 6 CONDUIT 0 00:00 4.14 1.00 3.05 2.49 1.23 1.00 1439 SURCHARGED {STORM _P1}.1-56 to 1-55 CONDUIT 0 00:00 2.57 1.00 1.63 2.71 0.60 1.00 1439 SURCHARGED {STORM _P1}.1-57 to 1-58 CONDUIT 0 07:55 1.85 1.00 0.16 2.76 0.06 0.17 0 Calculated {STORM _P1}.1-58 to 1-59 CONDUIT 0 07:55 0.57 1.00 0.27 4.30 0.06 0.59 0 Calculated {STORM _P1}.1-60 to 1-59 CONDUIT 0 00:02 1.49 1.00 0.77 2.53 0.30 0.86 0 Calculated {STORM _P1}.1-61 to 1-60 CONDUIT 0 07:59 0.77 1.00 0.21 2.51 0.08 0.51 0 Calculated {STORM _P1}.1-62 to 1-63 CONDUIT 0 08:00 1.66 1.00 0.14 2.76 0.05 0.17 0 Calculated {STORM _P1}.1-63 to 1-64 CONDUIT 0 08:00 1.43 1.00 0.20 2.76 0.07 0.23 0 Calculated {STORM _P1}.1-63A to 1-63 CONDUIT 0 07:56 0.80 1.00 0.05 2.82 0.02 0.14 0 Calculated {STORM _P1}.1-64 to 1-65 CONDUIT 0 08:00 2.35 1.00 0.43 2.77 0.16 0.28 0 Calculated {STORM _P1}.1-64A to 1-64 CONDUIT 0 08:00 1.75 1.00 0.24 4.08 0.06 0.23 APPENDIX E-1 0 Calculated {STORM _P1}.1-65 to 1-66 CONDUIT 0 08:00 2.21 1.00 0.46 2.75 0.17 0.31 0 Calculated {STORM _P1}.1-65A to 1-65 CONDUIT 0 07:58 0.22 1.00 0.03 2.73 0.01 0.24 0 Calculated {STORM _P1}.1-66 to 1-67 CONDUIT 0 08:00 2.62 1.00 0.59 2.78 0.21 0.33 0 Calculated {STORM _P1}.1-66A to 1-66 CONDUIT 0 08:00 0.73 1.00 0.13 2.82 0.05 0.29 0 Calculated {STORM _P1}.1-67A to 1-67 CONDUIT 0 07:59 0.25 1.00 0.03 2.82 0.01 0.27 0 Calculated {STORM _P1}.1-68A to 1-68 CONDUIT 0 08:00 0.56 1.00 0.08 2.96 0.03 0.41 0 Calculated {STORM _P1}.1-68B to 1-68 CONDUIT 0 07:59 0.55 1.00 0.06 3.78 0.02 0.41 0 Calculated {STORM _P1}.1-69A to 1-69 CONDUIT 0 00:01 1.68 1.00 0.51 2.82 0.18 0.97 0 Calculated {STORM _P1}.1-70 to Filterra 1 CONDUIT 0 00:00 5.33 1.00 3.57 5.04 0.71 1.00 1440 SURCHARGED {STORM _P1}.1-72 to 1-73 CONDUIT 0 07:54 1.57 1.00 1.23 2.77 0.44 1.00 138 SURCHARGED {STORM _P1}.1-73 to 1-74 CONDUIT 0 07:59 1.69 1.00 1.33 2.77 0.48 1.00 1435 SURCHARGED {STORM _P1}.1-74 to 1-75 CONDUIT 0 00:02 2.31 1.00 1.55 2.78 0.56 1.00 1437 SURCHARGED {STORM _P1}.1-75 to 1-76 CONDUIT 0 00:02 3.22 1.00 2.21 2.76 0.80 1.00 1438 SURCHARGED {STORM _P1}.1-75 to 1-78 CONDUIT 0 00:00 6.63 1.00 5.18 2.77 1.87 1.00 1439 SURCHARGED {STORM _P1}.SD 1-77A to 1-77 CONDUIT 0 07:54 1.21 1.00 0.14 2.27 0.06 0.59 0 Calculated {STORM _P1}.SD 86 (STORM _P1) CONDUIT 0 07:53 2.33 1.00 0.11 4.83 0.02 0.16 0 Calculated {STORM _P1}.SD 87 (STORM _P1) CONDUIT 0 07:54 2.91 1.00 0.11 6.17 0.02 0.10 0 Calculated {STORM _P1}.SD 88 (STORM _P1) CONDUIT 0 07:54 3.44 1.00 0.22 6.05 0.04 0.22 0 Calculated {STORM _P1}.SD 89 (STORM _P1) CONDUIT 0 00:00 4.75 1.00 3.53 2.77 1.27 1.00 1440 SURCHARGED APPENDIX E-1 {STORM _P1}.SD 97 (STORM _P1) CONDUIT 0 08:00 2.05 1.00 0.62 2.76 0.22 0.41 0 Calculated {STORM _P1}.SD 98 (STORM _P1) CONDUIT 0 08:01 1.20 1.00 0.76 2.76 0.27 0.75 0 Calculated {STORM _P1}.SD 99 (STORM _P1) CONDUIT 0 00:01 2.10 1.00 1.16 2.77 0.42 1.00 24 SURCHARGED {STORM _P1}.TD-A to 1-62 CONDUIT 0 08:00 2.66 1.00 0.14 0.19 0.76 0.59 0 Calculated {STORM _P1}.TD-C to 1.1 CONDUIT 0 07:54 2.66 1.00 0.23 0.74 0.31 0.69 0 Calculated 1-45 to 1-46 CONDUIT 0 07:55 1.44 1.00 0.10 2.20 0.05 0.15 0 Calculated 1-59 to 1-70 CONDUIT 0 00:01 2.52 1.00 1.44 2.21 0.65 1.00 1437 SURCHARGED BIOPOD 5 to 1-2 CONDUIT 0 07:54 9.49 1.00 2.80 4.37 0.64 1.00 9 SURCHARGED Link-03 CONDUIT 0 07:54 3.90 1.00 2.80 3.09 0.91 0.86 0 Calculated Link-04 CONDUIT 0 07:55 1.44 1.00 0.10 0.16 0.58 0.72 0 Calculated SD 1-78 to 1-15 CONDUIT 0 00:00 10.45 1.00 8.21 2.37 3.47 1.00 1440 SURCHARGED ******************************** Highest Flow Instability Indexes ******************************** All links are stable. Analysis began on: Fri Jan 9 10:31:56 2026 Analysis ended on: Fri Jan 9 10:32:02 2026 Total elapsed time: 00:00:06 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 APPENDIX E-1 Technical Information Report New Renton High School Project No. 2230388.10 Appendix F Stormwater Pollution Prevention and Spill Plan Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors Stormwater Pollution Prevention and Spill Plan PREPARED FOR: BRIC Architecture Inc. 1233 NW Northrup Street, Suite 100 Portland, OR 97209 PROJECT: New Renton High School 400 South 2nd Street Renton, WA 98057 Project No. 2230388.10 PREPARED BY: Brian Schend, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: January 2026 Stormwater Pollution Prevention and Spill Plan PREPARED FOR: BRIC Architecture Inc. 1233 NW Northrup Street, Suite 100 Portland, OR 97209 PROJECT: New Renton High School 400 South 2nd Street Renton, WA 98057 Project No. 2230388.10 PREPARED BY: Brian Schend, PE Senior Engineer REVIEWED BY: William J. Fierst, PE Principal DATE: January 2026 I hereby state that this Stormwater Pollution Prevention and Spill Plan for the New Renton High School project has been prepared by me or under my supervision and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Renton does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. 01/12/2026 Stormwater Pollution Prevention and Spill Plan New Renton High School Project No. 2230388.10 Table of Contents Section Page 1.0 Project Overview ............................................................................................................................ 1 1.1 Purpose and Scope............................................................................................................. 1 1.2 Pre-Developed Condition .................................................................................................... 1 1.3 Post-Development Condition .............................................................................................. 1 2.0 CSWPPP Analysis and Design ..................................................................................................... 2 2.1 ESC Plan Analysis and Design (Part A) ............................................................................. 2 2.1.1 ESC Supervisor...................................................................................................... 5 2.1.2 Documentation ....................................................................................................... 5 2.1.3 Review Timing ........................................................................................................ 5 2.2 Stormwater Pollution Prevention and Spill (SWPPS) Plan Design (Part B) ....................... 5 2.2.1 Pollution and Spill Prevention Source Controls and BMPs ................................... 6 2.2.2 Responsible Personnel and Contact Information .................................................. 7 2.2.3 Pollution and Spill Prevention Worksheets ............................................................ 8 2.2.4 Disposal Methods................................................................................................... 8 3.0 Financial/Ownership Responsibilities ......................................................................................... 8 Stormwater Pollution Prevention and Spill Plan New Renton High School Project No. 2230388.10 Attachments F-1.............Vicinity Map F-2.1 ..........Temporary Sediment Tank Sizing Calculations, Phase 1 F-2.2 ..........Temporary Sediment Tank Sizing Calculations, Phase 2 (to be included in a future submittal) F-2.3 ..........Temporary Sediment Tank Sizing Calculations, Phase 3 (to be included in a future submittal) F-3.............ESC and SWPPS Maintenance Report F-4.............ESC Maintenance Instructions F-5.............SWPPS Forms Stormwater Pollution Prevention and Spill Plan New Renton High School 1 Project No. 2230388.10 1.0 Project Overview 1.1 Purpose and Scope This report accompanies the civil engineering plans and documents used to describe the methodology and design criteria related to the storm design for the New Renton High School project. This report accompanies the civil engineering plans and documents for the subject project, located at 400 S 2nd St, Renton, Washington. The total project site occupies 43 parcels that total 35.2 acres. Refer to Attachment F-1 for the Vicinity Map. The 2021 King County Surface Water Design Manual (KCSWDM) and 2022 City of Renton Amendments to the King County Surface Water Design Manual (City of Renton Amendments) establish the methodology and design criteria used for the project. This three-phase project will construct a new high school building, as well as play fields, parking, and utilities. Phase 1 will construct new parking and utilities. Phase 2 will construct a new high school building northeast of the existing building, as well as play fields. Phase 3 will demolish a portion of the existing building and construct new parking and loading areas. 1.2 Pre-Developed Condition The project site is made up of 43 parcels for a total of 35.2 acres. The largest parcel includes the existing Renton High School and associated parking, utilities, and play fields. The existing high school is in three sections: the original building from the 1930s, an addition from the 1960s, and the IKEA Performing Arts Center (IPAC) from the 1990s. The high school site also includes a district warehouse. Most of the remaining parcels are privately owned for residential or commercial use, and the school district plans to purchase them for expansion of the school. The site has been fully disturbed and contains no natural forests. The topography of the site is flat, with elevations ranging from 25 to 38 feet, and most slopes flatter than 5%. The site is split between three threshold discharge areas (TDAs). TDA 1 and TDA 2 flow through a series of pipes, catch basins, and manholes, and eventually discharge to the Black River. TDA 3 flows through a series of pipes, catch basins, and manholes, and discharges to the Cedar River. 1.3 Post-Development Condition The proposed project will construct a new high school in three phases. The first phase will include new parking and drop-off areas. The second phase will construct a new building to the north and east of the IPAC, as well as play fields. The third phase will demolish the 1960s portion of the existing building and the district warehouse and construct new parking and loading areas. The 1930s portion of the building and the IPAC will remain. The completed project will consist of 4.8 acres of buildings, 13.7 acres of pavement, 2.3 acres of natural turf fields, and 7.2 acres of artificial turf fields (including rubberized track), and the remainder will be landscaping. Parking areas will be located to the west and northwest of the completed building. Roads will access the building on the north, west, and south side, including emergency access. An access roadway across what is currently S Tobin St will provide access to the play fields. Access to the site will be by driveways on S 2nd St, Lake Ave, S Tobin St, and Logan Ave S. Runoff from the site will be directed to the public storm drainage system in the surrounding public streets. Areas of pollution generating surface will be directed to Filterra devices for treatment. Portions of the building and parking areas will be directed to a detention tank system that will be located west of the 1930s portion of the existing building. Phase 1 and Phase 3 of construction will discharge solely to the Black River. Only Phase 2 includes areas that discharge to the Cedar River. Stormwater Pollution Prevention and Spill Plan New Renton High School 2 Project No. 2230388.10 2.0 CSWPPP Analysis and Design The proposed development will comply with guidelines set forth in the stormwater manuals and will be in conformance with the required Construction Stormwater General Permit. The plan includes erosion/sedimentation control (ESC) measures designed to prevent sediment-laden runoff from leaving the site or from adversely affecting critical water resources during construction. 2.1 ESC Plan Analysis and Design (Part A) The erosion potential of the site is influenced by four major factors: soil characteristics, vegetative cover, topography, and climate. ESC is achieved by a combination of structural measures, cover measures, and construction practices that are tailored to fit the specific site. The following measures will be used to control erosion/sedimentation processes. These measures comply with the Erosion and Sediment Control Standards in the stormwater manuals. Clearing Limits Prior to beginning land-disturbing activities, clearing limits will be marked with high-visibility plastic fence or temporary construction fencing. Significant vegetation to remain will be marked and protected by fencing. Cover Measures Disturbed areas shall be permanently or temporarily covered, as required in the stormwater manuals. Temporary measures may include plastic sheeting, mulch, gravel, asphalt treated base, and quarry spalls. Permanent measures include vegetation and pavement. Perimeter Protection Silt fence will be installed as indicated on the TESC plans. The silt fence will help remove sediment from surface water and will provide some flow control. Traffic Area Stabilization Asphalt treated base or gravel surfacing will be used for stabilized construction entrances. Wheel washing and/or street sweeping will be provided, as necessary, to prevent tracking of sediment onto adjacent surfaces. Sediment Retention Inlet protection devices will be installed in all existing, temporary, and new catch basins. Silt fence will be installed at the perimeter of the disturbed areas located adjacent to downhill slopes. Small sediment traps will be used around the site, as well as check dams in conjunction with interceptor swales, to capture further sediment. Additionally, temporary sediment tanks will be constructed for each phase of construction. All runoff during construction will be conveyed to the tanks before being conveyed to the City’s stormwater system. Tank sizing calculations for Phase 1 are included in Attachment F-2.1. Calculations for Phase 2 and Phase 3 will be provided in a future submittal. Neither the KCSWDM nor the City of Renton Amendments provide any guidance for the sizing of temporary stormwater tank systems. Instead, we used the guidance provided by the City of Tacoma Stormwater Management Manual (SWMM). The City of Tacoma SWMM specifies to first determine a pump capacity capable of pumping the 25-year, 24-hour storm. It then gives a total tank capacity of Pump Discharge in GPM * 16 = Storage in cubic feet. The attached calculations use this method to show the required temporary tank sizing. Stormwater Pollution Prevention and Spill Plan New Renton High School 3 Project No. 2230388.10 Surface Water Collection Surface water from the construction site will be collected and conveyed with interceptor swales, temporary catch basins, and temporary drainpipes. This water will then be piped to the temporary sediment tanks, which discharge to the City’s storm drainage system. Inlet protection devices will be installed in all new and existing catch basins, and silt fence will be installed at the perimeter of the disturbed areas located adjacent to downhill slopes. These measures will assist with removing sediment from surface water. Dewatering Control Water may be encountered during ground disturbing activities. If water is encountered, the contractor shall remove it and dispose of it in a manner that does not pollute surface water or cause downstream erosion or flooding. Examples of disposal options include use of a sedimentation bag with outfall to a swale for small volumes of localized dewatering or transporting it in a vehicle for legal offsite disposal. Dust Control As necessary, the contractor shall spray exposed soils with water to prevent wind transport of soil. Flow Control Silt fence and check dams will provide some level of flow control for surface water. Additionally, all runoff generated during construction will be conveyed to the temporary sediment tanks, which are sized per the stormwater manuals and provides the needed flow control for construction. Control Pollutants All waste materials will be collected and stored in a securely closed metal dumpster. All trash and construction debris from the site will be deposited in the dumpster. The dumpster will be emptied a minimum of once per week, and the trash will be hauled to the local landfill. No construction materials will be buried onsite. All personnel will be instructed regarding the correct procedure for waste disposal. All sanitary waste will be collected from the portable units a minimum of three times per week. Good housekeeping and spill control practices will be followed during construction to minimize stormwater contamination from petroleum products, fertilizers, and concrete. Table 1 below lists pollutants that are commonly found on construction sites that have the potential to contaminate storm runoff. These pollutants will be present, mainly in areas of building and pavement construction. The contractor and Erosion and Sedimentation Control (ESC) Supervisor will be responsible for identifying areas where these pollutants are being used and will monitor runoff coming from these areas. Pollutant sources will be covered with plastic if contaminated runoff is observed from these areas. If contaminated runoff is found in the sediment trap or soils, the ESC Supervisor will direct the contractor to remove the polluted water/soil and dispose of it in an approved area offsite. Table 1 – Potential Construction Site Stormwater Pollutants Trade Name Material Chemical/Physical Description (1) Stormwater Pollutants (1) Pesticides (insecticides, fungicides, herbicide, rodenticides) Various colored to colorless liquid, powder, pellets, or grains Chlorinated hydrocarbons, organophosphates, carbamates, arsenic Fertilizer Liquid or solid grains Nitrogen, phosphorous Stormwater Pollution Prevention and Spill Plan New Renton High School 4 Project No. 2230388.10 Trade Name Material Chemical/Physical Description (1) Stormwater Pollutants (1) Plaster White granules or powder Calcium sulphate, calcium carbonate, sulfuric acid Cleaning solvents Colorless, blue, or yellow- green liquid Perchloroethylene, methylene chloride, trichloroethylene, petroleum distillates Asphalt Black solid Oil, petroleum distillates Concrete White solid Limestone, sand Glue, adhesives White or yellow liquid Polymers, epoxies Paints Various colored liquid Metal oxides, stoddard solvent, talc, calcium carbonate, arsenic Curing compounds Creamy white liquid Naphtha Wastewater from construction equipment washing Water Soil, oil & grease, solids Wood preservatives Clear amber or dark brown liquid Stoddard solvent, petroleum distillates, arsenic, copper, chromium Hydraulic oil/fluids Brown oily petroleum hydrocarbon Mineral oil Gasoline Colorless, pale brown or pink petroleum hydrocarbon Benzene, ethyl benzene, toluene, xylene, MTBE Diesel fuel Clear, blue-green to yellow liquid Petroleum distillate, oil & grease, naphthalene, xylenes Kerosene Pale yellow liquid petroleum hydrocarbon Coal oil, petroleum distillates Antifreeze/coolant Clear green/yellow liquid Ethylene glycol, propylene glycol, heavy metals (copper, lead, zinc) Erosion Solid Particles Soil, Sediment (1) Data obtained from MSDS when available. Protect Existing and Proposed BMPs Temporary and permanent erosion and sediment control Best Management Practices (BMPs) shall be maintained and repaired as needed to assure performance of their intended functions. Sediment control BMPs such as silt fencing, plastic covering, and drain inlet protection shall be inspected weekly or after a runoff-producing event. Temporary erosion and sediment control BMPs will be removed within 30 days after final site stabilization is achieved. The following inspection and maintenance practices will be used to maintain erosion and sediment controls. • Built-up sediment will be removed from silt fencing when it has reached one-third the height of the fence. • Silt fences will be inspected for depth of sediment, tears in the fabric, and attachment to the fence posts, and to ensure that fence posts are firmly in the ground. Accumulated sediment will be removed from behind the fence. • Check dams will be inspected for depth of sediment. Accumulated sediment will be removed when it reaches 6 inches in depth. • Temporary and permanent seeding will be inspected for bare spots, washouts, and healthy growth. • The contractor ESC Supervisor will provide erosion control inspection services and stormwater disposal monitoring through construction. The City Inspector will be notified of daily construction activities and scheduled meetings between the ESC Supervisor and the contractor. Stormwater Pollution Prevention and Spill Plan New Renton High School 5 Project No. 2230388.10 The maintenance inspection report will be made after each inspection. Copies of the report forms to be completed by the ESC Supervisor are attached in Attachment F-3 of this SWPPS. Completed forms will be provided to the City Inspector and will also be maintained onsite during the entire construction project. If construction activities or design modifications are made to the site plan that could impact stormwater, or if AHBL determines that the measures are not adequate to prevent erosion and the discharge of sediment from the site (based on turbidity measurements), this SWPPS will be amended appropriately. The amended SWPPS will have a description of the new activities that contribute to the increased pollutant loading and the planned source control activities. Maintain BMPs All ESC measures shall be maintained and reviewed on a regular basis, as prescribed in the maintenance requirements of each BMP (see Attachment F-4). Manage the Project The following practices will be required during construction to properly manage activities: • Comply with seasonal work limitations. • Inspect, maintain, and repair BMPs. • Maintain the SWPPS onsite at all times, including narrative and plans. 2.1.1 ESC Supervisor The contractor shall designate an Erosion and Sedimentation Control (ESC) Supervisor who shall be responsible for maintenance and review of ESC and for compliance with all permit conditions relating to ESC. The ESC Supervisor must be available for rapid response to ESC problems. The ESC Supervisor is required to be a Certified Erosion and Sedimentation Control Lead (CESCL), with demonstrated expertise in ESC to perform these reviews and to be responsible for ESC implementation. 2.1.2 Documentation The ESC Supervisor shall review the site at least once a month during the dry season, weekly during the wet season, and within 24 hours of significant storms. Written records of these reviews shall be kept onsite, with copies submitted to the City of Renton within 48 hours. If the City requires that a written record be maintained, a standard ESC Maintenance Report, included here as Attachment F-3, may be used. A copy of all required maintenance reports shall be kept onsite throughout the duration of construction. 2.1.3 Review Timing During the wet season, weekly reviews shall be carried out every six to eight calendar days. During the dry season, monthly reviews shall be carried out within three days of the calendar day for the last inspection (e.g., if an inspection occurred on June 6, then the next inspection must occur between July 3 and July 9). Reviews shall also take place within 24 hours of significant storms. In general, a significant storm is one with more than 0.5 inch of rain in 24 hours or less. Another indication that a storm is "significant" is if gullies form as a result of the runoff. 2.2 Stormwater Pollution Prevention and Spill (SWPPS) Plan Design (Part B) The below SWPPS Plan shall be completed by the contractor for use during construction of the project. Blanks are intentional as they are part of the contractor’s means and methods. Stormwater Pollution Prevention and Spill Plan New Renton High School 6 Project No. 2230388.10 The SWPPS Plan includes three elements: a site plan, a pollution prevention report, and a spill prevention and cleanup report. This report includes identifying the expected sources of potential pollution and spills that may occur during construction, and works to develop a plan to prevent pollution and spills. It also develops a plan to mitigate spills that may occur. The SWPPS Plan will be kept onsite at all times during construction. The general contractor will be responsible to ensure that subcontractors are aware of the SWPPS Plan, and a form or record will be provided stating that all subcontractors have read and agree to the SWPPS Plan. An employee training worksheet is provided for the contractor’s use (see Attachment F-5). A SWPPS Site Plan will be developed by the contractor. The SWPPS Site Plan, Pollution Prevention Report, and Spill Prevention and Cleanup Report were preliminarily developed and BMPs were selected based on the text of the stormwater manuals. 2.2.1 Pollution and Spill Prevention Source Controls and BMPs The sources of pollution and spills are identified below, and the BMPs to be used for each source for prevention of both pollution and spills are listed below. Liquids and Chemicals: Tight-fitting lids shall be placed on all containers containing liquids. Containers shall be covered with plastic sheeting during rain events. Drip pans or absorbent materials shall be placed beneath all mounted container taps and at all potential drip and spill locations during filling and unloading of containers. Containers shall be stored such that if a container leaks or spills, the contents will not be discharged, flow, or be washed into the storm drainage system, surface water, or groundwater. Appropriate spill cleanup materials shall be stored and maintained near the container storage area. Storage area shall be swept and cleaned as needed. Area shall not be hosed down such that water drains to the storm drainage system or neighboring areas. Containers shall be checked daily for leaks and spills and replaced, as necessary. All spilled liquids will be collected and disposed of properly. Spill control devices shall be routinely inspected on a weekly basis. Dry pesticides and fertilizers shall be covered with plastic sheeting or stored in a sealed container. Materials shall be stored on pallets or another raised method to prevent contact with stormwater runoff. Alternatively, the materials shall be contained in a manner such that if the container leaks or spills, the contents will not discharge, flow, or be washed into the storm drainage system, surface waters, or groundwater. Maintenance requirements are the same as liquid materials described above. Soil, sand, and other erodible materials shall be stored onsite in a contractor-designated location. Materials shall be covered with plastic sheeting per standard detail. Perimeter controls shall be constructed as shown on the TESC plan to prevent eroded materials from leaving the project site. Fueling shall not occur onsite. If fueling does occur onsite, the contractor shall develop a containment plan for spills and provide lighting and signage if fueling occurs at night in conformance with the KCSPPM. Maintenance and repair of vehicles shall not occur onsite. If maintenance or repair of vehicles does occur onsite, the contractor shall develop a spill prevention plan in conformance with the stormwater manuals. Truck wheel washing shall occur in a controlled manner, such that runoff is collected and disposed of in a legal manner. Rinsing of hand tools shall occur in a designated location, and water for washing shall be collected and disposed of in a legal manner. Stormwater Pollution Prevention and Spill Plan New Renton High School 7 Project No. 2230388.10 Contaminated soils shall be covered with plastic sheeting or contained to prevent stormwater from carrying pollutants away to surface or ground waters. Appropriate spill cleanup materials, such as brooms, dustpans, vacuum sweepers, etc., shall be stored and maintained near the storage area. Storage area shall be swept and cleaned as needed. Area shall not be hosed down such that water drains to the storm drainage system, groundwater, surface water, or neighboring areas. During concrete and asphalt construction, the contractor shall provide the following BMPs or equivalent measures, methods or practices as required: 1. Drip pans, ground cloths, heavy cardboard, or plywood wherever concrete, asphalt, and asphalt emulsion chunks and drips are likely to fall unintentionally, such as beneath extraction points from mixing equipment. 2. Storm drains shall be covered to prevent concrete and asphalt from entering the storm system. 3. Concrete, concrete slurry, and rinse water shall be contained and collected, and shall not be washed or allowed to discharge into storm drain, ditch, or neighboring parcels. All collected runoff shall be properly disposed of. 4. Contractor shall designate an area where application and mixing equipment cleaning will be conducted. Rinse water and slurry shall be collected, contained, and disposed of in a legal manner. 5. Routine maintenance: the pouring area shall be swept at the end of each day or more frequently if needed. Loose aggregate chunks and dust shall be collected. Areas shall not be hosed down. The contractor may provide the following optional BMPs if the above do not provide adequate source controls: 6. Cover portable mixing equipment with an awning or plastic sheeting to prevent contact with rainfall. 7. Provide catch basin inserts configured for pollutant removal. pH elevated water shall not be discharged from the site. Contractor shall monitor stormwater for pH prior to discharging from the site. Contractor shall implement a pH treatment plan if pH is not within the natural range. 2.2.2 Responsible Personnel and Contact Information The contractor shall designate an ESC Supervisor and post their contact name, company, and phone number and/or email in a readily visible location onsite and fill out the table below. Designated ESC Supervisor: Name: Company: Phone: Email: Contractor shall fill out the attached Pollution Prevention Team Worksheet (see Attachment F-5). Stormwater Pollution Prevention and Spill Plan New Renton High School 8 Project No. 2230388.10 2.2.3 Pollution and Spill Prevention Worksheets Pollution prevention, BMP implementation reports, material inventory worksheets, pollutant source identification worksheet, and spill/leak report may be found attached as Attachment F-5 2.2.4 Disposal Methods Contractor shall dispose of contaminated soils and water in a legal manner. 3.0 Financial/Ownership Responsibilities The owner, Renton School District, will be responsible for providing all bonds and financial guarantees associated with the project. A bond quantity worksheet is included in the TIR report for this project. This analysis is based on data and records either supplied to or obtained by AHBL. These documents are referenced within the text of the analysis. The analysis was prepared using procedures and practices within the standard accepted practices of the industry. We conclude that this project will not create any new problems within the downstream drainage system. This project will not noticeably aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. Brian Schend, PE Senior Engineer BJS/lsk January 2026 Q:\2023\2230388\WORDPROC\Reports\20260112 Rpt (SWPPS Plan) 2230388.10.docx Stormwater Pollution Prevention and Spill Plan New Renton High School Project No. 2230388.10 Attachments F-1 .................... Vicinity Map F-2.1 ................. Temporary Sediment Tank Sizing Calculations, Phase 1 F-2.2 ................. Temporary Sediment Tank Sizing Calculations, Phase 2 (to be included in a future submittal) F-2.3 ................. Temporary Sediment Tank Sizing Calculations, Phase 3 (to be included in a future submittal) F-3 .................... ESC and SWPPS Maintenance Report F-4 .................... ESC Maintenance Instructions F-5 .................... SWPPS Forms VICINITY MAP I405 AIRPORT WAY S TOBIN ST S 2ND ST R A I N I E R A V E F-1 Vicinity Map T T T T T T TT T S TOBIN ST S TOBIN ST LO G A N A V E S LA K E A V E S S 2nd ST 1930s BUILDING 1990s BUILDING (IPAC) 1960s BUILDING 1960s BUILDING 1960s BUILDING 1960s BUILDING DISTURBED AREA TO TEMPORARY TANKS 4.6 ACRES ASSUME 90% IMPERVIOUS DURING CONSTRUCTION DISTURBED AREA 0.4 ACRES DISTURBED AREA 0.2 ACRES DISTURBED AREAS 0.2 ACRES 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO. DATE: RENTON HIGH SCHOOL TEMPORARY TESC TANKS BASINS PHASE 1 F-2.1 2230388.10 12/18/2025 N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 Autodesk® Storm and Sanitary Analysis 2024 - Version 13.6.323 (Build 0) ------------------------------------------------------------------------------------ ----- ******************* Project Description ******************* File Name ................. RHS-TESC-Phase 1.SPF Description ............... Q:\2023\2230388\10_CIV\CAD\_2230388-W-STRM_P1.dwg **************** Analysis Options **************** Flow Units ................ cfs Subbasin Hydrograph Method. Santa Barbara UH Time of Concentration...... SCS TR-55 Storage Node Exfiltration.. None Starting Date ............. DEC-11-2025 00:00:00 Ending Date ............... DEC-12-2025 00:00:00 Report Time Step .......... 00:00:10 ************* Element Count ************* Number of rain gages ...... 1 Number of subbasins ....... 1 Number of nodes ........... 1 Number of links ........... 0 **************** Raingage Summary **************** Gage Data Data Recording ID Source Type Interval min ------------------------------------------------------------ Renton City of Renton CUMULATIVE 6.00 **************** Subbasin Summary **************** Subbasin Total Imperv. Raingage Area Area ID acres % ---------------------------------------------------- TESC Basin Phase 1 4.60 90.00 Renton ************ Node Summary ************ Node Element Invert Maximum Ponded External ID Type Elevation Elev. Area Inflow ft ft ft² ------------------------------------------------------------------------------ TESC OUTFALL 0.00 0.00 0.00 ************************** Volume Depth Runoff Quantity Continuity acre-ft inches ************************** --------- ------- Total Precipitation ...... 1.263 3.294 Surface Runoff ........... 1.099 2.868 Continuity Error (%) ..... 0.000 ************************** Volume Volume Flow Routing Continuity acre-ft Mgallons ************************** --------- --------- External Inflow .......... 0.000 0.000 External Outflow ......... 1.099 0.358 Initial Stored Volume .... 0.000 0.000 Final Stored Volume ...... 0.000 0.000 Continuity Error (%) ..... 0.000 ****************************************** Composite Curve Number Computations Report ****************************************** ------------------------------ Subbasin TESC Basin Phase 1 ------------------------------ Area Soil Soil/Surface Description (acres) Group CN ------------------------------------------------------------------------------------ ---- Composite Area & Weighted CN 4.60 95.70 ************************************** Runoff Coefficient Computations Report ************************************** ------------------------------ Subbasin TESC Basin Phase 1 ------------------------------ Area Soil Runoff Soil/Surface Description (acres) Group Coeff. ------------------------------------------------------------------------------------ ----- - 4.60 - 0.72 Composite Area & Weighted Runoff Coeff. 4.60 0.72 *************************************************** SCS TR-55 Time of Concentration Computations Report *************************************************** Sheet Flow Equation ------------------- Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where: Tc = Time of Concentration (hrs) n = Manning's Roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation ---------------------------------- V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation --------------------- V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hrs) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's Roughness ------------------------------ Subbasin TESC Basin Phase 1 ------------------------------ ==================================================================================== ============ Total TOC (minutes): 0.00 ==================================================================================== ============ *********************** Subbasin Runoff Summary *********************** -------------------------------------------------------------------------- Subbasin Total Total Peak Weighted Time of ID Precip Runoff Runoff Curve Concentration in in cfs Number days hh:mm:ss -------------------------------------------------------------------------- TESC Basin Phase 1 3.29 2.87 3.24 95.700 0 00:06:00 -------------------------------------------------------------------------- Analysis began on: Fri Dec 19 14:04:27 2025 Analysis ended on: Fri Dec 19 14:04:28 2025 Peak runoff 3.24 CFS Total elapsed time: 00:00:01 Peak runoff 3.24 CFS. Use 1500 GPM pump. Tank volume is pump GPM * 16 = volume in cubic feet Tank volume = 24,000 CF = 180,000 gallons SECTION D.4 REFERENCE SECTION 6/22/2022 2022 City of Renton Surface Water Design Manual D-130 D.4.3 ESC AND SWPPS MAINTENANCE REPORTS CED may require a written record of all maintenance activities to be kept to demonstrate compliance with the Maintenance Requirements (Section D.2.4.4). A standard ESC Maintenance Report is provided on the next page and typical SWPPS Maintenance Reports follow. Copies of the ESC and SWPPS Maintenance Reports must be kept on site throughout the duration of construction. E S C M A I N T E N A N C E R E P O R T Performed By: ___________________________ Date: ___________________________ Project Name: ___________________________ CED Permit #: ___________________________ Clearing Limits Damage OK Problem Visible OK Problem Intrusions OK Problem Other OK Problem Mulch Rills/Gullies OK Problem Thickness OK Problem Other OK Problem Nets/Blankets Rills/Gullies OK Problem Ground Contact OK Problem Other OK Problem Plastic Tears/Gaps OK Problem Other OK Problem Seeding Percent Cover OK Problem Rills/Gullies OK Problem Mulch OK Problem Other OK Problem Sodding Grass Health OK Problem Rills/Gullies OK Problem Other OK Problem Perimeter Protection Including Silt Fence Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem BMP/Facility Protection Damage OK Problem Sedimentation OK Problem Concentrated Flow OK Problem Rills/Gullies OK Problem Intrusions OK Problem Other OK Problem Brush Barrier Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2022 City of Renton Surface Water Design Manual 6/22/2022 D-131 Vegetated Strip Damage OK Problem Sediment Build-up OK Problem Concentrated Flow OK Problem Other OK Problem Construction Entrance Dimensions OK Problem Sediment Tracking OK Problem Vehicle Avoidance OK Problem Other OK Problem Wheel Wash Dimensions OK Problem Sed buildup or tracking OK . Problem Other OK Problem Construction Road Stable Driving Surf. OK Problem Vehicle Avoidance OK Problem Other OK Problem Sediment Trap/Pond Sed. Accumulation OK Problem Overtopping OK Problem Inlet/Outlet Erosion OK Problem Other OK Problem Catch Basin/Inlet Protection Sed. Accumulation OK Problem Damage OK Problem Clogged Filter OK Problem Other OK Problem Interceptor Dike/Swale Damage OK Problem Sed. Accumulation OK Problem Overtopping OK Problem Other OK Problem Pipe Slope Drain Damage OK Problem Inlet/Outlet OK Problem Secure Fittings OK Problem Other OK Problem Ditches Damage OK Problem Sed. Accumulation OK Problem Overtopping OK Problem Other OK Problem Outlet Protection Scour OK Problem Other OK Problem Level Spreader Damage OK Problem Concentrated Flow OK Problem Rills/Gullies OK Problem Sed. Accumulation OK Problem Other OK Problem Dewatering Controls Sediment OK Problem Dust Control Palliative applied OK Problem SECTION D.4 REFERENCE SECTION 6/22/2022 2022 City of Renton Surface Water Design Manual D-132 Miscellaneous Wet Season Stockpile OK Problem Other OK Problem Comments: Actions Taken: Problems Unresolved: CITY OF RENTON SURFACE WATER DESIGN MANUAL 2022 City of Renton Surface Water Design Manual 6/22/2022 D-9 D.2 GENERAL CSWPP REQUIREMENTS To satisfy the City of Renton’s requirements for CSWPP, the following steps are required of all construction projects: 1. Design the plan: In accordance with Sections 2.3.1 and 2.3.3 of the SWDM, prepare and submit a technical information report (TIR) and a CSWPP plan (comprised of the ESC plan and the SWPPS plan) for City review. Utilize the standards and details for ESC (Section D.2.1) and SWPPS control (Section D.2.2) of this appendix. Incorporate any City of Renton review comments as necessary to comply with Core Requirement #5, Section 1.2.5 of the SWDM, the Erosion and Sediment Control and Stormwater Pollution Prevention and Spill Control Standards in this appendix. 2. Construct the approved plan: Construct initial ESC, SWPPS and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection measures on site according to the approved CSWPP plan. 3. Maintain the BMPs: Inspect and maintain all CSWPP measures and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection throughout construction in accordance with the inspection and maintenance standards of Section D.2.4.4. Keep current any required documentation and reporting. 4. Manage the project: Make any changes or additions necessary during construction to ensure that CSWPP measures and stormwater facility (flow control facility, runoff treatment facility, and on-site BMP) protection perform in accordance with Core Requirement #5 and Sections D.2.1, D.2.2 and D.2.4. Coordinate construction in consideration of the applied BMP strategies. Ensure pollutant controls, facility processes and reporting requirements are met in accordance with Section D.2.3. The CSWPP supervisor is the primary point of contact for all ESC and SWPPP issues (see Section D.2.3.1). 5. Conclude the plan: Prior to final construction approval, meet all the conditions in Section D.2.4.5 for final stabilization. A National Pollutant Discharge Elimination System (NPDES) General Permit for Construction (pursuant to the Washington State Department of Ecology’s Construction Stormwater General Permit) may also be required for projects that will disturb one or more acres (see SWDM Section 1.2.5.3 for additional information). Proposed projects subject to Simplified Drainage Review as determined in SWDM Section 1.1.2.1 may satisfy City of Renton CSWPP requirements by meeting the Small Site CSWPP requirements specified in Section D.3 and reiterated in Appendix C of the SWDM titled, “Simplified Drainage Requirements.” D.2.1 ESC MEASURES This section details the ESC measures that are required to minimize erosion and sediment transport off a construction site and protect areas of existing and proposed stormwater facilities (flow control facilities, runoff treatment facilities, and on-site BMPs). These ESC measures represent Best Management Practices (BMPs)6 for the control of erosion and entrained sediment as well as other impacts related to construction such as increased runoff due to land disturbing activities. The measures and practices are grouped into nine sections corresponding to each of the nine categories of ESC measures in Core Requirement #5, Section 1.2.5 of the SWDM. The introductory paragraphs at the beginning each section present the basic requirement for that category of measures, the purpose of those measures, installation requirements relative to construction activity, guidelines for the conditions of use, and other information relevant to all measures in the section/category. Compliance with each of the nine categories of the ESC measures, to the 6 Best Management Practices (BMPs) means the best available and reasonable physical, structural, managerial, or behavioral activities, that when singly or in combination, eliminate or reduce the contamination of surface and/or ground waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-10 extent applicable and necessary to meet the performance criteria in Section D.2.1, and compliance with the ESC implementation requirements in Section D.2.4, constitutes overall compliance with the City’s ESC Standards. Note: Additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. The standards for each individual ESC measure are divided into four sections: 1. Purpose 2. Conditions of Use 3. Design and Installation Specifications 4. Maintenance Requirements. A code and symbol for each measure have also been included for ease of use on ESC plans. Note that the “Conditions of Use” always refers to site conditions. As site conditions change, ESC measures must be changed to remain in compliance with the requirements of this appendix. Whenever compliance with the City’s ESC Standards is required, all of the following categories of ESC measures must be considered for application to the project site as detailed in the following sections: 1. Clearing Limits: Prior to any site clearing or grading, areas to remain undisturbed during project construction shall be delineated on the project’s ESC plan and physically marked on the project site. 2. Cover Measures: Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas. The intent of these measures is to prevent erosion by having as much area as possible covered during any period of precipitation. 3. Perimeter Protection: Perimeter protection to filter sediment from sheet flow shall be provided downstream of all disturbed areas prior to upslope grading. 4. Traffic Area Stabilization: Unsurfaced entrances, roads, and parking areas used by construction traffic shall be stabilized to minimize erosion and tracking of sediment offsite. 5. Sediment Retention: Surface water collected from all disturbed areas of the site shall be routed through a sediment pond or trap prior to release from the site, except those areas at the perimeter of the site small enough to be treated solely with perimeter protection. Sediment retention facilities shall be installed prior to grading any contributing area. 6. Surface Water Collection: Surface water collection measures (e.g., ditches, berms, etc.) shall be installed to intercept all surface water from disturbed areas, convey it to a sediment pond or trap, and discharge it downstream of any disturbed areas. Areas at the perimeter of the site, which are small enough to be treated solely with perimeter protection, do not require surface water collection. Significant sources of upstream surface water that drain onto disturbed areas shall be intercepted and conveyed to a stabilized discharge point downstream of the disturbed areas. Surface water collection measures shall be installed concurrently with or immediately following rough grading and shall be designed, constructed, and stabilized as needed to minimize erosion. 7. Dewatering Control: The water resulting from construction site de-watering activities must be treated prior to discharge or disposed of as specified. 8. Dust Control: Preventative measures to minimize wind transport of soil shall be implemented when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources. 9. Flow Control: Surface water from disturbed areas must be routed through the project’s onsite flow control facility or other provisions must be made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction (flow control D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-11 facility, runoff treatment facility, and on-site BMP areas [existing or proposed] shall not be used for this purpose). 10. Control Pollutants: Stormwater pollution prevention (SWPPS) measures are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsite equipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. Section D.2.2 describes BMPs specific to this purpose; additionally, several of the ESC BMPs described herein are applicable. 11. Protect Existing and Proposed Stormwater Facilities and On-site BMPs: Sedimentation and soil compaction reduce the infiltration capacity of native and engineered soils. Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities and on-site BMPs. 12. Maintain Protective BMPs: Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing BMPs/facilities and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. 13. Manage the Project: Coordination and timing of site development activities relative to ESC concerns, and timely inspection, maintenance and update of protective measures are necessary to effectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. D.2.1.1 CLEARING LIMITS Prior to any site clearing or grading, those areas that are to remain undisturbed during project construction shall be delineated. At a minimum, clearing limits shall be installed at the edges of all critical area buffers and any other areas required to be left uncleared such as portions of the site subject to clearing limits under RMC 4-4-060, areas around significant trees identified to be retained, on-site BMP areas to be protected, and other areas identified to be left undisturbed to protect sensitive features. Purpose: The purpose of clearing limits is to prevent disturbance of those areas of the project site that are not designated for clearing or grading. This is important because limiting site disturbance is the single most effective method for reducing erosion. Clearing limits may also be used to control construction traffic, thus reducing the disturbance of soil and limiting the amount of sediment tracked off site. When to Install: Clearing limits shall be installed prior to the clearing and/or grading of the site. Measures to Use: Marking clearing limits by delineating the site with a continuous length of brightly colored survey tape is sometimes sufficient. The tape may be supported by vegetation or stakes, and it shall be 3 to 6 feet high and highly visible. Critical areas and their buffers require more substantial protection and shall be delineated with plastic or metal safety fences or stake and wire fences. Fencing may be required at the City’s discretion to control construction traffic or at any location where greater protection is warranted. Permanent fencing may also be used if desired by the applicant. Silt fence, in combination with survey flagging, is also an acceptable method of marking critical areas and their buffers. D.2.1.1.1 PLASTIC OR METAL FENCE Code: FE Symbol: Purpose Fencing is intended to (1) restrict clearing to approved limits; (2) prevent disturbance of critical areas, their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect areas where marking with survey tape may not provide adequate protection. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-12 Conditions of Use To establish clearing limits, plastic or metal fence may be used: 1. At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2. As necessary to control vehicle access to and on the site (see Sections D.2.1.4.1 and D.2.1.4.2). Design and Installation Specifications 1. The fence shall be designed and installed according to the manufacturer’s specifications. 2. The fence shall be at least 3 feet high and must be highly visible. 3. The fence shall not be wired or stapled to trees. Maintenance Requirements 1. If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. 2. Disturbance of a critical area, critical area buffer, native growth retention area, or any other area required to be left undisturbed shall be reported to the City for resolution. D.2.1.2 COVER MEASURES Temporary and permanent cover measures shall be provided to protect all disturbed areas, including the faces of cut and fill slopes. Temporary cover shall be installed if an area is to remain unworked for more than seven days during the dry season (May 1 to September 30) or for more than two consecutive working days during the wet season (October 1 to April 30). These time limits may be relaxed if an area poses a low risk of erosion due to soil type, slope gradient, anticipated weather conditions, or other factors. Conversely, the City may reduce these time limits if site conditions warrant greater protection (e.g., adjacent to significant aquatic resources or highly erosive soils) or if significant precipitation (see Section D.2.4.2) is expected. Any area to remain unworked for more than 30 days shall be seeded or sodded, unless the City determines that winter weather makes vegetation establishment infeasible. During the wet season, slopes and stockpiles at 3H:1V or steeper and with more than ten feet of vertical relief shall be covered if they are to remain unworked for more than 12 hours. Also during the wet season, the material necessary to cover all disturbed areas must be stockpiled on site. The intent of these cover requirements is to have as much area as possible covered during any period of precipitation. Purpose: The purpose of covering exposed soils is to prevent erosion, thus reducing reliance on less effective methods that remove sediment after it is entrained in runoff. Cover is the only practical method of reducing turbidity in runoff. Structural measures, such as silt fences and sediment ponds, are only capable of removing coarse particles and in most circumstances have little to no effect on turbidity. When to Install: Any exposed soils that will remain unworked for more than the time limit set above shall be covered by the end of the working day. If the exposed area is to remain unworked for more than 30 days, the area shall be seeded with the temporary seed mix or an equivalent mix that will provide rapid protection (see Section D.2.1.2.6). If the disturbed area is to remain unworked for a year or more or if the area has reached final grade, permanent seed mix or an equivalent mix shall be applied. Measures to Use: Cover methods include the use of surface roughening, mulch, erosion control nets and blankets, plastic covering, seeding, and sodding. Mulch and plastic sheeting are primarily intended to protect disturbed areas for a short period of time, typically days to a few months. Seeding and sodding are measures for areas that are to remain unworked for months. Erosion nets and blankets are to be used in conjunction with seeding steep slopes. The choice of measures is left to the designer; however, there are restrictions on the use of these methods, which are listed in the “Conditions of Use” and the “Design and Installation Specifications” sections for each measure. The methods listed are by no means exhaustive. Variations on the standards presented here are encouraged if other cost-effective products or methods provide substantially equivalent or superior performance. Also, D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-13 the details of installation can, and should, vary with the site conditions. A useful reference on the application of cover measures in the Puget Sound area is Improving the Cost Effectiveness of Highway Construction Site Erosion and Pollution Control, Horner, Guedry, and Kortenhof (1990). D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-15 D.2.1.2.2 MULCHING Code: MU Symbol: Purpose The purpose of mulching soils is to provide immediate temporary protection from erosion. Mulch also enhances plant establishment by conserving moisture, holding fertilizer, seed, and topsoil in place, and moderating soil temperatures. There is an enormous variety of mulches that may be used. Only the most common types are discussed in this section. Conditions of Use As a temporary cover measure, mulch should be used: 1. On disturbed areas that require cover measures for less than 30 days 2. As a cover for seed during the wet season and during the hot summer months 3. During the wet season on slopes steeper than 3H:1V with more than 10 feet of vertical relief. Design and Installation Specifications For mulch materials, application rates, and specifications, see Table D.2.1.2.A. Note: Thicknesses may be increased for disturbed areas in or near critical areas or other areas highly susceptible to erosion. Maintenance Standards 1. The thickness of the cover must be maintained. 2. Any areas that experience erosion shall be remulched and/or protected with a net or blanket. If the erosion problem is drainage related, then the drainage problem shall be assessed and alternate drainage such as interceptor swales may be needed to fix the problem and the eroded area remulched. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-16 TABLE D.2.1.2.A MULCH STANDARDS AND GUIDELINES Mulch Material Quality Standards Application Rates Remarks Straw Air-dried; free from undesirable seed and coarse material 2″–3″ thick; 5 bales per 1,000 sf or 2– 3 tons per acre Cost-effective protection when applied with adequate thickness. Hand-application generally requires greater thickness than blown straw. Straw should be crimped to avoid wind blow. The thickness of straw may be reduced by half when used in conjunction with seeding. Wood Fiber Cellulose No growth inhibiting factors Approx. 25–30 lbs per 1,000 sf or 1,500–2,000 lbs per acre Shall be applied with hydromulcher. Shall not be used without seed and tackifier unless the application rate is at least doubled. Some wood fiber with very long fibers can be effective at lower application rates and without seed or tackifier. Compost No visible water or dust during handling. Must be purchased from supplier with Solid Waste Handling Permit. 2″ thick min.; approx. 100 tons per acre (approx. 1.5 cubic feet per square yard) More effective control can be obtained by increasing thickness to 3″ (2.25 cubic feet per square yard). Excellent mulch for protecting final grades until landscaping because it can be directly seeded or tilled into soil as an amendment. Compost may not be used in Sensitive Lake7 basins unless analysis of the compost shows no phosphorous release. Hydraulic Matrices (Bonded Fiber Matrix [BFM]) This mulch category includes hydraulic slurries composed of wood fiber, paper fiber or a combination of the two held together by a binding system. The BFM shall be a mixture of long wood fibers and various bonding agents. Apply at rates from 3,000 lbs per acre to 4,000 lbs per acre and based on manufacturers recommendations The BFM shall not be applied immediately before, during or immediately after rainfall so that the matrix will have an opportunity to dry for 24 hours after installation. Application rates beyond 2,500 pounds may interfere with germination and are not usually recommended for turf establishment. BFM is generally a matrix where all fiber and binders are in one bag, rather than having to mix components from various manufacturers to create a matrix. BFMs can be installed via helicopter in remote areas. They are approximately $1,000 per acre cheaper to install. Chipped Site Vegetation Average size shall be several inches. 2″ minimum thickness This is a cost-effective way to dispose of debris from clearing and grubbing, and it eliminates the problems associated with burning. Generally, it should not be used on slopes above approx. 10% because of its tendency to be transported by runoff. It is not recommended within 200 feet of surface waters. If seeding is expected shortly after mulch, the decomposition of the chipped vegetation may tie up nutrients important to grass establishment. 7 Sensitive lake means a lake that has proved to be particularly prone to eutrophication; the City did not have any lakes that had this designation at the time of SWDM adoption. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-17 D.2.1.2.3 NETS AND BLANKETS Code: NE Symbol: Purpose Erosion control nets and blankets are intended to prevent erosion and hold seed and mulch in place on steep slopes and in channels so that vegetation can become well established. In addition, some nets and blankets can be used to permanently reinforce turf to protect drainage ways during high flows. Nets are strands of material woven into an open, but high-tensile strength net (for example, jute matting). Blankets are strands of material that are not tightly woven, but instead form a layer of interlocking fibers, typically held together by a biodegradable or photodegradable netting (for example, excelsior or straw blankets). They generally have lower tensile strength than nets, but cover the ground more completely. Coir (coconut fiber) fabric comes as both nets and blankets. Conditions of Use Erosion control nets and blankets should be used: 1. For permanent stabilization of slopes 2H:1V or greater and with more than 10 feet of vertical relief. 2. In conjunction with seed for final stabilization of a slope, not for temporary cover. However, they may be used for temporary applications as long as the product is not damaged by repeated handling. In fact, this method of slope protection is superior to plastic sheeting, which generates high-velocity runoff (see Section D.2.1.2.4). 3. For drainage ditches and swales (highly recommended). The application of appropriate netting or blanket to drainage ditches and swales can protect bare soil from channelized runoff while vegetation is established. Nets and blankets also can capture a great deal of sediment due to their open, porous structure. Synthetic nets and blankets may be used to permanently stabilize channels and may provide a cost-effective, environmentally preferable alternative to riprap. Design and Installation Specifications 1. See Figure D.2.1.2.B and Figure D.2.1.2.C for typical orientation and installation of nettings and blankets. Note: Installation is critical to the effectiveness of these products. If good ground contact is not achieved, runoff can concentrate under the product, resulting in significant erosion. 2. With the variety of products available, it is impossible to cover all the details of appropriate use and installation. Therefore, it is critical that the design engineer thoroughly consults the manufacturer’s information and that a site visit takes place in order to ensure that the product specified is appropriate. 3. Jute matting must be used in conjunction with mulch (Section D.2.1.2.2). Excelsior, woven straw blankets, and coir (coconut fiber) blankets may be installed without mulch. There are many other types of erosion control nets and blankets on the market that may be appropriate in certain circumstances. Other types of products will have to be evaluated individually. In general, most nets (e.g., jute matting) require mulch in order to prevent erosion because they have a fairly open structure. Blankets typically do not require mulch because they usually provide complete protection of the surface. 4. Purely synthetic blankets are allowed but shall only be used for long-term stabilization of waterways. The organic blankets authorized above are better for slope protection and short-term waterway protection because they retain moisture and provide organic matter to the soil, substantially improving the speed and success of re-vegetation. Maintenance Standards 1. Good contact with the ground must be maintained, and there must not be erosion beneath the net or blanket. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-18 2. Any areas of the net or blanket that are damaged or not in close contact with the ground shall be repaired and stapled. 3. If erosion occurs due to poorly controlled drainage, the problem shall be fixed and the eroded area protected. FIGURE D.2.1.2.B WATERWAY INSTALLATION OF NETS AND BLANKETS FIGURE D.2.1.2.C SLOPE INSTALLATION OF NETS AND BLANKETS DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLS TO MOLD TO ANY IRREGULARITIES. SLOPE SURFACE SHALL BE SMOOTH BEFORE PLACEMENT FOR PROPER SOIL CONTACT. ANCHOR, STAPLE, AND INSTALL CHECK SLOTS AS PER MANUFACTURER'S RECOMMENDATIONS. AVOID JOINING MATERIAL IN THE CENTER OF THE DITCH. LIME, FERTILIZE AND SEED BEFORE INSTALLATION. MIN.4" OVERLAP' MIN.6" OVERLAP SLOPE SURFACE SHALL BE SMOOTH BEFORE PLACEMENT FOR PROPER SOIL CONTACT STAPLING PATTERN AS PER MANUFACTURER'S RECOMMENDATION MIN. 2" OVERLAP LIME, FERTILIZE AND SEED BEFORE INSTALLATION. PLANTING OF SHRUBS, TREES, ETC. SHOULD OCCUR AFTER INSTALLATION DO NOT STRETCH BLANKETS/MATTINGS TIGHT - ALLOW THE ROLLS TO MOLD TO ANY IRREGULARITIES FOR SLOPES LESS THAN 3H:1V, ROLLS MAY BE PLACED IN HORIZONTAL STRIPS BRING MATERIAL DOWN TO A LEVEL AREA, TURN THE END UNDER 4" AND STAPLE AT 12" INTERVALS ANCHOR IN 6"x6" MIN. TRENCH AND STAPLE AT 12" INTERVALS STAPLE OVERLAPS MAX. 5' SPACING IF THERE IS A BERM AT THE TOP OF SLOPE, ANCHOR UPSLOPE OF THE BERM MIN. 6" OVERLAP D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-19 D.2.1.2.4 PLASTIC COVERING Code: PC Symbol: Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use 1. Plastic covering may be used on disturbed areas that require cover measures for less than 30 days. 2. Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term applications. 3. Clear plastic sheeting may be used over newly-seeded areas to create a greenhouse effect and encourage grass growth. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass. 4. Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. Note: There have been many problems with plastic, usually attributable to poor installation and maintenance. However, the material itself can cause problems, even when correctly installed and maintained, because it generates high-velocity runoff and breaks down quickly due to ultraviolet radiation. In addition, if the plastic is not completely removed, it can clog drainage system inlets and outlets. It is highly recommended that alternatives to plastic sheeting be used whenever possible and that its use be limited. Design and Installation Specifications 1. See Figure D.2.1.2.D for details. 2. Plastic sheeting shall have a minimum thickness of 0.06 millimeters. 3. If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. FIGURE D.2.1.2.D PLASTIC COVERING TIRES, SANDBAGS, OR EQUIVALENT MAY BE USED TO WEIGHT PLASTIC SEAMS BETWEEN SHEETS MUST OVERLAP A MINIMUM OF 12" AND BE WEIGHTED OR TAPED TOE IN SHEETING IN MINIMUM 4"X4" TRENCH PROVIDE ENERGY DISSIPATION AT TOE WHEN NEEDED 10' MAX. 10' MAX. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-20 Maintenance Standards for Plastic Covering 1. Torn sheets must be replaced and open seams repaired. 2. If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced. 3. When the plastic is no longer needed, it shall be completely removed. D.2.1.2.5 STRAW WATTLES Code: SW Symbol: Purpose Wattles are erosion and sediment control barriers consisting of straw wrapped in biodegradable tubular plastic or similar encasing material. Wattles may reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Straw wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. The wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. Conditions of Use 1. Install on disturbed areas that require immediate erosion protection. 2. Use on slopes requiring stabilization until permanent vegetation can be established. 3. Can be used along the perimeter of a project, as a check dam in unlined ditches and around temporary stockpiles 4. Wattles can be staked to the ground using willow cuttings for added revegetation. 5. Rilling can occur beneath and between wattles if not properly entrenched, allowing water to pass below and between wattles Design and Installation Specifications 1. It is critical that wattles are installed perpendicular to the flow direction and parallel to the slope contour. 2. Narrow trenches should be dug across the slope, on contour, to a depth of 3 to 5 inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and during high rainfall events, the trenches should be dug to a depth of 5 to 7 inches, or ½ to 2/3 of the thickness of the wattle. 3. Start construction of trenches and installing wattles from the base of the slope and work uphill. Excavated material should be spread evenly along the uphill slope and compacted using hand tamping or other method. Construct trenches at contour intervals of 3 to 30 feet apart depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches should be constructed. Vertical distance between wattles is not to exceed 10 feet. 4. Install the wattles snugly into the trenches and abut tightly end to end. Do not overlap the ends. 5. Install stakes at each end of the wattle, and at 4 foot centers along the entire length of the wattle. 6. If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. 7. At a minimum, wooden stakes should be approximately ¾ x ¾ x 24 inches. Willow cuttings or 3/8 inch rebar can also be used for stakes. 8. Stakes should be driven through the middle of the wattle, leaving 2 to 3 inches of the stake protruding above the wattle. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-21 Maintenance Standards 1. Inspect wattles prior to forecasted rain, daily during extended rain events, after rain events, weekly during the wet season, and at two week intervals at all other times of the year. 2. Repair or replace split, torn, raveling, or slumping wattles 3. Remove sediment accumulations when exceeding ½ the height between the top of the wattle and the ground surface. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-22 FIGURE D.2.1.2.E STRAW WATTLES 1. STRAW ROLL INSTALLATION REQUIRES THE PLACEMENT AND SECURE STAKING OF THE ROLL IN A TRENCH, 3" x 5" (75-125mm) DEEP, DUG ON CONTOUR. 2. RUNOFF MUST NOT BE ALLOWED TO RUN UNDER OR AROUND ROLL. ROLL SPACING DEPENDS ON SOIL TYPE AND SLOPE STEEPNESS STRAW ROLLS MUST BE PLACED ALONG SLOPE CONTOURS 3'-4' (1.2m) 10'-25' (3-8m) 3"-5" (75-125mm) ADJACENT ROLLS SHALL TIGHTLY ABUT SEDIMENT, ORGANIC MATTER, AND NATIVE SEEDS ARE CAPTURED BEHIND THE ROLLS LIVE STAKE 1" x 1" STAKE 8"-10" DIA. (200-250mm) NOTES: STRAW WATTLES NTS D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-23 D.2.1.2.6 TEMPORARY AND PERMANENT SEEDING Code: SE Symbol: Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use 1. Seeding shall be used throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. 2. Vegetation-lined channels shall be seeded. Channels that will be vegetated should be installed before major earthwork and hydroseeded or covered with a Bonded Fiber Matrix (BFM). 3. Retention/detention ponds shall be seeded as required. 4. At the City’s discretion, seeding without mulch during the dry season is allowed even though it will take more than seven days to develop an effective cover. Mulch is, however, recommended at all times because it protects seeds from heat, moisture loss, and transport due to runoff. 5. Prior to the beginning of the wet season, all disturbed areas shall be reviewed to identify which ones can be seeded in preparation for the winter rains (see Section D.2.4.2). Disturbed areas shall be seeded within one week of the beginning of the wet season. A sketch map of those areas to be seeded and those areas to remain uncovered shall be submitted to the CED inspector. The CED inspector may require seeding of additional areas in order to protect surface waters, adjacent properties, or drainage facilities. 6. At final site stabilization, all disturbed areas not otherwise vegetated or stabilized shall be seeded and mulched (see Section D.2.4.5). Design and Installation Specifications 1. The best time to seed is fall (late September to October) or in spring (mid-March to June). Irrigation is required during the first summer following installation if seeding occurs in spring or summer or during prolonged dry times of year. Areas may also be seeded during the winter months, but it may take additional spring seeding applications to develop a dense groundcover due to cold temperatures. The application and maintenance of mulch is critical for winter seeding. 2. To prevent seed from being washed away, confirm that all required surface water control measures have been installed. 3. The seedbed should not be compacted because soils that are well compacted will not vegetate as quickly or thoroughly. Slopes steeper than 3H:1V shall be surface roughened. Roughening can be accomplished in a variety of ways, but the typical method is track walking, or driving a crawling tractor up and down the slope, leaving cleat imprints parallel to the slope contours. 4. In general, 10-20-20 N-P-K (nitrogen-phosphorus-potassium) fertilizer may be used at a rate of 90 pounds per acre. Slow-release fertilizers are preferred because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertilizer needed. This will prevent the over- application of fertilizer. Disturbed areas within 200 feet of water bodies and wetlands must use slow- release low-phosphorus fertilizer (typical proportions 3-1-2 N-P-K). 5. The following requirements apply to mulching: a) Mulch is always required for seeding slopes greater than 3H:1V (see Section D.2.1.2.2). b) If seeding during the wet season, mulch is required. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-24 c) The use of mulch may be required during the dry season at the City’s discretion if grass growth is expected to be slow, the soils are highly erodible due to soil type or gradient, there is a water body close to the disturbed area, or significant precipitation (see Section D.2.4.2) is anticipated before the grass will provide effective cover. d) Mulch may be applied on top of the seed or simultaneously by hydroseeding. 6. Hydroseeding is allowed as long as tackifier is included. Hydroseeding with wood fiber mulch is adequate during the dry season. Application of hydroseeded wood fiber mulch should be appropriate for slope angle. Follow manufacturer specifications for application rates. 7. Areas to be permanently landscaped shall use soil amendments. Good quality topsoil shall be tilled into the top six inches to reduce the need for fertilizer and improve the overall soil quality. Most native soils will require the addition of four inches of well-rotted compost to be tilled into the soil to provide a good quality topsoil. Compost used should meet specifications provided in Reference Section 11-C of the SWDM. 8. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetland mix, shall be applied at a rate of 80 to 100 seeds per square foot. Wet sites should apply 120 to 150 seeds per square foot. Local suppliers should be consulted for information on current Pure Live Seed (PLS) rates and species specific seeds per pound in order to determine seed mix PLS pounds of seed per acre. The appropriate mix depends on a variety of factors, including exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by the City may be used. Table D.2.1.2.B presents the standard mix for those areas where temporary or permanent vegetative cover is required. The following mix assumes a desired 150 seeds per square foot and should be applied at approximately 37 pounds of pure live seed per acre. TABLE D.2.1.2.B EROSION CONTROL SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Spike bentgrass/Agrostis exarata 6 9 0.1 California brome/Bromus carinatus 15 23 9.8 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 Blue wildrye/Elymus glaucus 18 27 10.7 California oatgrass/Danthonia californica 18 27 5.6 Native red fescue/Festuca rubra var. rubra 18 27 2.4 Meadow barley/Hordeum brachyantherum 10 15 7.7 Table D.2.1.2.C provides just one recommended possibility for landscaping seed. It assumes a desired 100 seeds per square foot and should be applied at 18 pounds of pure live seed per acre. TABLE D.2.1.2.C LANDSCAPING SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Sideoats grama/Bouteloua curtipendula 20 30 6.8 California oatgrass/Danthonia californica 20 30 6.2 Native red fescue/Festuca rubra var. rubra 30 45 3.9 Prairie junegrass/Koeleria macrantha 30 45 0.8 D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-25 This turf seed mix in Table D.2.1.2.D is for dry situations where there is no need for much water. The advantage is that this mix requires very little maintenance. TABLE D.2.1.2.D LOW-GROWING TURF SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Hard fescue/Festuca brevipila 25 20 1.5 Sheep fescue/Festuca ovina 30 24 1.5 Native red fescue/Festuca rubra var. rubra 25 20 1.7 Prairie junegrass/Koeleria macrantha 20 16 0.3 Table D.2.1.2.E presents a mix recommended for bioswales and other intermittently wet areas. The mix assumes a desired 150 seeds per square foot and approximately 29 pounds of pure live seed per acre. Sod shall generally not be used for bioswales because the seed mix is inappropriate for this application. Sod may be used for lining ditches to prevent erosion, but it will provide little water quality benefit during the wet season. TABLE D.2.1.2.E BIOSWALE SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre American sloughgrass/Beckmannia syzigachne 15 23 0.9 Tufted hairgrass/Deschampsia cespitosa 20 30 0.5 Blue wildrye/Elymus glaucus 18 27 10.7 Native red fescue/Festuca rubra var. rubra 20 30 2.6 Meadow barley/Hordeum brachyantherum 12 18 9.2 Northwestern mannagrass/Glyceria occidentalis 15 23 4.9 The seed mix shown in Table D.2.1.2.F is a recommended low-growing, non-invasive seed mix appropriate for very wet areas that are not regulated wetlands (if planting in wetland areas, see Section 6.3.1 of the SWDM). Other mixes may be appropriate, depending on the soil type and hydrology of the area. This mixture assumes a target goal of 150 seeds per square foot and should be applied at a rate of 36 pounds per acre. TABLE D.2.1.2.F WET AREA SEED MIX* Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre California brome/Bromus carinatus 15 23 9.8 Columbia brome/Bromus vulgaris 18 27 8.1 Tufted hairgrass/Deschampsia cespitosa 15 23 0.4 California oatgrass/Danthonia californica 15 23 4.7 Native red fescue/Festuca rubra var. rubra 17 26 2.2 Western manna grass/Glyceria occidentalis 10 15 3.3 Meadow barley/Hordeum brachyantherum 10 15 7.7 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-26 The meadow seed mix in Table D.2.1.2.G is recommended for areas that will be maintained infrequently or not at all and where colonization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. This seed mix assumes a target goal of 120 seeds per square foot and an application rate of 23 pounds of pure live seed per acre. TABLE D.2.1.2.G MEADOW SEED MIX Common Name/Latin Name % Species Composition Desired Seeds per Square Foot PLS Pounds/Acre Common yarrow/Achillea millefolium 4 5 0.1 Pearly everlasting/Anaphalis margartacae 1 1 0.0 California brome/Bromus carinatus 15 18 7.8 California oatgrass/Danthonia californica 15 18 3.7 Blue wildrye/Elymus glaucus 16 19 7.6 Festuca idahoensis 15 18 1.7 Native red fescue/Festuca rubra var. rubra 18 22 1.9 Sickle keeled lupine/Lupinus albicaulis 1 1 2.2 Fowl bluegrass/Poa palustris 15 18 0.4 Maintenance Standards for Temporary and Permanent Seeding 1. Any seeded areas that fail to establish at least 80 percent cover within one month shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding or nets/blankets, shall be used. If winter weather prevents adequate seed establishment and growth, this time limit may be relaxed at the discretion of the City when critical areas would otherwise be protected. 2. After adequate cover is achieved, any areas that experience erosion shall be re-seeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area re- seeded and protected by mulch. 3. Seeded areas shall be supplied with adequate moisture, but not watered to the extent that it causes runoff. D.2.1.2.7 SODDING Code: SO Symbol: Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: 1. Disturbed areas that require short-term or long-term cover 2. Disturbed areas that require immediate vegetative cover 3. All waterways that require vegetative lining (except biofiltration swales—the seed mix used in most sod is not appropriate for biofiltration swales). Waterways may also be seeded rather than sodded, and protected with a net or blanket (see Section D.2.1.2.3). D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-27 Design and Installation Specifications Sod shall be free of weeds, of uniform thickness (approximately 1-inch thick), and shall have a dense root mat for mechanical strength. The following steps are recommended for sod installation: 1. Shape and smooth the surface to final grade in accordance with the approved grading plan. 2. Amend four inches (minimum) of well-rotted compost into the top eight inches of the soil if the organic content of the soil is less than ten percent. Compost used shall meet compost specifications per SWDM Reference Section 11-C. 3. Fertilize according to the supplier’s recommendations. Disturbed areas within 200 feet of water bodies and wetlands must use non-phosphorus fertilizer. 4. Work lime and fertilizer 1 to 2 inches into the soil, and smooth the surface. 5. Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least 12 inches. Staple on slopes steeper than 3H:1V. 6. Roll the sodded area and irrigate. 7. When sodding is carried out in alternating strips or other patterns, seed the areas between the sod immediately after sodding. Maintenance Standards If the grass is unhealthy, the cause shall be determined and appropriate action taken to reestablish a healthy groundcover. If it is impossible to establish a healthy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-30 D.2.1.3 PERIMETER PROTECTION Perimeter protection to filter sediment from sheetwash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Perimeter protection includes the use of vegetated strips as well as, constructed measures, such as silt fences, fiber rolls, sand/gravel barriers, brush or rock filters, triangular silt dikes and other methods. During the wet season, 50 linear feet of silt fence (and the necessary stakes) per acre of disturbed area must be stockpiled on site. Purpose: The purpose of perimeter protection is to reduce the amount of sediment transported beyond the disturbed areas of the construction site. Perimeter protection is primarily a backup means of sediment control. Most, if not all, sediment-laden water is to be treated in a sediment trap or pond. The only D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-31 circumstances in which perimeter control is to be used as a primary means of sediment removal is when the catchment is very small (see below). When to Install: Perimeter protection is to be installed prior to any upslope clearing and grading. Measures to Use: The above measures may be used interchangeably and are not the only perimeter protection measures available. If surface water is collected by an interceptor dike or swale and routed to a sediment pond or trap, there may be no need for the perimeter protection measures specified in this section. Criteria for Use as Primary Treatment: At the boundary of a site, perimeter protection may be used as the sole form of treatment when the flowpath meets the criteria listed below. If these criteria are not met, perimeter protection shall only be used as a backup to a sediment trap or pond. Average Slope Slope Percent Flowpath Length 1.5H:1V or less 67% or less 100 feet 2H:1V or less 50% or less 115 feet 4H:1V or less 25% or less 150 feet 6H:1V or less 16.7% or less 200 feet 10H:1V or less 10% or less 250 feet D.2.1.3.1 SILT FENCE Code: SF Symbol: Purpose Use of a silt fence reduces the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Silt fence may be used downslope of all disturbed areas. 2. Silt fence is not intended to treat concentrated flows, nor is it intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a silt fence, rather than by a sediment trap or pond, is when the area draining to the fence is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3 above). Design and Installation Specifications 1. See Figure D.2.1.3.A and Figure D.2.1.3.B for details. 2. The geotextile used must meet the standards listed below. A copy of the manufacturer’s fabric specifications must be available on site. AOS (ASTM D4751) 30–100 sieve size (0.60–0.15 mm) for slit film 50–100 sieve size (0.30–0.15 mm) for other fabrics Water Permittivity (ASTM D4491) 0.02 sec-1 minimum Grab Tensile Strength (ASTM D4632) (see Specification Note 3) 180 lbs. min. for extra strength fabric 100 lbs. min. for standard strength fabric Grab Tensile Elongation (ASTM D4632) 30% max. (woven) Ultraviolet Resistance (ASTM D4355) 70% min. 3. Standard strength fabric requires wire backing to increase the strength of the fence. Wire backing or closer post spacing may be required for extra strength fabric if field performance warrants a stronger fence. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-32 4. Where the fence is installed, the slope shall be no steeper than 2H:1V. 5. If a typical silt fence (per Figure D.2.1.3.A) is used, the standard 4 x 4 trench may be reduced as long as the bottom 8 inches of the silt fence fabric is well buried and secured in a trench that stabilizes the fence and does not allow water to bypass or undermine the silt fence. Maintenance Standards 1. Any damage shall be repaired immediately. 2. If concentrated flows are evident uphill of the fence, they must be intercepted and conveyed to a sediment trap or pond. 3. It is important to check the uphill side of the fence for signs of the fence clogging and acting as a barrier to flow and then causing channelization of flows parallel to the fence. If this occurs, replace the fence or remove the trapped sediment. 4. Sediment must be removed when the sediment is 6 inches high. 5. If the filter fabric (geotextile) has deteriorated due to ultraviolet breakdown, it shall be replaced. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-33 FIGURE D.2.1.3.A SILT FENCE 2"X2" BY 14 Ga. WIRE OR EQUIVALENT, IF STANDARD STRENGTH FABRIC USED NOTE: FILTER FABRIC FENCES SHALL BE INSTALLED ALONG CONTOURS WHENEVER POSSIBLE JOINTS IN FILTER FABRIC SHALL BE SPLICED AT POSTS. USE STAPLES, WIRE RINGS OR EQUIVALENT TO ATTACH FABRIC TO POSTS. FILTER FABRIC BACKFILL TRENCH WITH NATIVE SOIL OR 3/4" TO 1-1/2" WASHED GRAVEL MINIMUM 4"x4" TRENCH 2"x4" WOOD POSTS, STEEL FENCE POSTS, REBAR, OR EQUIVALENT POST SPACING MAY BE INCREASED TO 8' IF WIRE BACKING IS USED 6' MAX. 2' M I N . 12 " M I N . SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-34 FIGURE D.2.1.3.B SILT FENCE INSTALLATION BY SLICING 1. GATHER FABRIC AT POSTS, IF NEEDED. 2. UTILIZE THREE TIES PER POST, ALL WITHIN TOP 8" OF FABRIC. 3. POSITION EACH TIE DIAGONALLY, PUNCTURING HOLES VERTICALLY A MINIMUM OF 1" APART. 4. HANG EACH TIE ON A POST NIPPLE AND TIGHTEN SECURELY. USE CABLE TIES (50 LBS) OF SOFT WIRE. TOP OF FABRIC BELT DIAGONAL ATTACHMENT DOUBLES STRENGTH FLOW ST E E L S U P P O R T P O S T 1. POST SPACING: 7' MAX. ON OPEN RUNS 4' MAX. ON POOLING AREAS. 2. POST DEPTH: AS MUCH BELOW GROUND AS FABRIC ABOVE GROUND. 3. PONDING HEIGHT MAX. 24" ATTACH FABRIC TO UPSTREAM SIDE OF POST. 4. DRIVE OVER EACH SIDE OF SILT FENCE 2 TO 4 TIMES WITH DEVICE EXERTING 60 P.S.I. OR GREATER. 5. NO MORE THAN 24" OF A 36" FABRIC IS ALLOWED ABOVE GROUND. 6. VIBRATORY PLOW IS NOT ACCEPTABLE BECAUSE OF HORIZONTAL COMPACTION. 100% COMPACTION EACH SIDE OPERATION ROLL OF SILT FENCE PLOW FABRIC ABOVE GROUND HORIZONTAL CHISEL POINT (76 mm WIDTH)200-300mm SILT FENCE TOP 8" NOTES: ATTACHMENT DETAILS: SILT FENCE INSTALLATION BY SLICING METHOD NTS D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-35 D.2.1.3.2 BRUSH BARRIER Code: BB Symbol: Purpose The purpose of brush barriers is to reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Brush barriers may be used downslope of all disturbed areas. 2. Brush barriers are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a barrier, rather than by a sediment trap or pond, is when the area draining to the barrier is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3). Design and Installation Specifications 1. See Figure D.2.1.3.C for details. 2. The City may require filter fabric (geotextile) anchored over the brush berm to enhance the filtration ability of the barrier. Maintenance Standards 1. There shall be no signs of erosion or concentrated runoff under or around the barrier. If concentrated flows are bypassing the barrier, it must be expanded or augmented by toed-in filter fabric. 2. The dimensions of the barrier must be maintained. FIGURE D.2.1.3.C BRUSH BARRIER IF REQUIRED, DRAPE FILTER FABRIC OVER BRUSH AND SECURE IN 4"x4" MIN. TRENCH WITH COMPACTED BACKFILL MAX. 6" DIAMETER WOODY DEBRIS FOR BARRIER CORE. ALTERNATIVELY TOPSOIL STRIPPINGS MAY BE USED TO FORM THE BARRIER. ANCHOR DOWNHILL EDGE OF FILTER FABRIC WITH STAKES, SANDBAGS, OR EQUIVALENT 2' MIN. HEIGHT 5' MIN. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-36 D.2.1.3.3 VEGETATED STRIP Code: VS Symbol: Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Vegetated strips may be used downslope of all disturbed areas. 2. Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a strip, rather than by a sediment trap or pond, is when the area draining to the strip is small (see “Criteria for Use as Primary Treatment” in Section D.2.1.3). Design and Installation Specifications 1. The vegetated strip shall consist of a 25-foot minimum width continuous strip of dense vegetation with a permeable topsoil. Grass-covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff. 2. The slope within the strip shall not exceed 4H:1V. 3. The uphill boundary of the vegetated strip shall be delineated with clearing limits as specified in Section D.2.1.1. Maintenance Standards 1. Any areas damaged by erosion or construction activity shall be seeded immediately and protected by mulch. 2. If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed using the standards for installation found in Section D.2.1.2.7. If there are indications that concentrated flows are traveling across the buffer, surface water controls must be installed to reduce the flows entering the buffer, or additional perimeter protection must be installed. D.2.1.3.4 TRIANGULAR SILT DIKE (GEOTEXTILE ENCASED CHECK DAM) Code: TSD Symbol: Purpose Triangular silt dikes (TSDs) may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Silt dikes, if attached to impervious surfaces with tack or other adhesive agent may also be used as temporary wheel wash areas, or concrete washout collection areas. Conditions of Use 1. May be used for temporary check dams in ditches. 2. May be used on soil or pavement with adhesive or staples. 3. TSDs have been used to build temporary sediment ponds, diversion ditches, concrete washout facilities, curbing, water bars, level spreaders, and berms. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-37 Design and Installation Specifications 1. TSDs must be made of urethane foam sewn into a woven geosynthetic fabric. 2. TSDs are triangular, 10 inches to 14 inches high in the center, with a 20-inch to 28-inch base. A 2-foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed 3. Install TSDs with ends curved up to prevent water from flowing around the ends 4. Attach the TSDs and their fabric flaps to the ground with wire staples. Wire staples must be No. 11 gauge wire or stronger and shall be 200 mm to 300 mm in length. 5. When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. 6. TSDs must be located and installed as soon as construction will allow. 7. TSDs must be placed perpendicular to the flow of water. 8. When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. 9. When used in grass-lined ditches and swales, the TSD check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the TSD check dams shall be seeded and mulched immediately after dam removal. Maintenance Standards 1. Triangular silt dikes shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall event. Sediment shall be removed when it reaches one half the height of the silt dike. 2. Anticipate submergence and deposition above the triangular silt dike and erosion from high flows around the edges of the dike/dam. Immediately repair any damage or any undercutting of the dike/dam. D.2.1.3.5 COMPOST BERMS Code: COBE Symbol: Purpose Compost berms are an option to meet the requirements of perimeter protection. Compost berms may reduce the transport of sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Compost berms trap sediment by filtering water passing through the berm and allowing water to pond, creating a settling area for solids behind the berm. Organic materials in the compost can also reduce concentrations of metals and petroleum hydrocarbons from construction runoff. Due to the increase in phosphorous seen in the effluent data from compost berms, they should be used with some cautions in areas that drain to phosphorus sensitive water bodies, and should only be used in Sensitive Lake watersheds, such as Lake Sammamish, with the approval from the City or the local jurisdiction. Conditions of Use 1. Compost berms may be used in most areas requiring sediment or erosion control where runoff is in the form of sheet flow or in areas where silt fence is normally considered acceptable. Compost berms may be used in areas where migration of aquatic life such as turtles and salamanders are impeded by the use of silt fence. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-38 2. Compost berms are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed via a drainage system to a sediment pond or trap. 3. For purposes of long-term sediment control objectives, berms may be seeded at the time of installation to create an additional vegetated filtering component. Design and Installation Specifications 1. Compost berms shall be applied using a pneumatic blower device or equivalent, to produce a uniform cross-section and berm density. 2. Compost berms shall be triangular in cross-section. The ratio of base to height dimensions shall be 2:1. 3. The minimum size of a compost berm is a 2-foot base with a 1-foot height. 4. Compost berms shall be sized and spaced as indicated in the table below. SLOPE SLOPE Maximum Slope Length or Berm Spacing (linear feet) Berm Size Required (height x base width) 0% – 2% Flatter than 50:1 250 1 ft x 2 ft 2% – 10% 50:1 – 10:1 125 1 ft x 2 ft 10% – 20% 10:1 – 5:1 100 1 ft x 2 ft 20% – 33% 5:1 – 3:1 75 1 ft x 2 ft 33% – 50% 3:1 – 2:1 50 1.5 ft x 3 ft 5. Compost berms shall not be used on slopes greater than 2H:1V. 6. Compost shall meet criteria in Reference Section 11-C of the SWDM except for the particle size distribution (see Bullet 8). 7. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. 8. Compost particle size distribution shall be as follows: 99% passing a 1 inch sieve, 90% passing a 3/4-inch sieve and a minimum of 70% greater than the 3/8-inch sieve. A total of 98% shall not exceed 3 inches in length. 9. Berms shall be placed on level contours to assist in dissipating flow into sheet flow rather than concentrated flows. Berms shall not be constructed to concentrate runoff or channel water. Sheet flow of water shall be perpendicular to the berm at impact. No concentrated flow shall be directed towards compost berms. 10. Where possible, berms shall be placed 5 feet or more from the toe of slopes to allow space for sediment deposition and collection. 11. In order to prevent water from flowing around the ends of the berms, the ends of the berm shall be constructed pointing upslope so the ends are at a higher elevation than the rest of the berm. 12. A compost blanket extending 10 to 15 feet above the berm is recommended where the surface above the berm is rutted or uneven, to reduce concentrated flow and promote sheet flow into the berm. Maintenance Standards 1. Compost berms shall be regularly inspected to make sure they retain their shape and allow adequate flow-through of stormwater. 2. When construction is completed on site, the berms shall be dispersed for incorporation into the soil or left on top of the site for final seeding to occur. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-39 3. Any damage to berms must be repaired immediately. Damage includes flattening, compacting, rills, eroded areas due to overtopping. 4. If concentrated flows are evident uphill of the berm, the flows must be intercepted and conveyed to a sediment trap or pond. 5. The uphill side of the berm shall be inspected for signs of the berm clogging and acting as a barrier to flows and causing channelization of flows parallel to the berm. If this occurs, replace the berm or remove the trapped sediment. 6. Sediment that collects behind the berm must be removed when the sediment is more than 6 inches deep. D.2.1.3.6 COMPOST SOCKS Code: COSO Symbol: Purpose Compost socks reduce the transport of sediment from a construction site by providing a temporary physical barrier to sediment-laden water and reducing the runoff velocities of overland flow. Compost socks trap sediment by filtering water that passes through the sock and allows water to pond behind the sock, creating a settling area for solids. Organic materials in the compost also may reduce metal and petroleum hydrocarbon concentrations in construction runoff. Compost socks function similarly to compost berms; however, because the compost is contained in a mesh tube, they are appropriate for both concentrated flow and sheet flow. Compost socks may be used to channel concentrated flow on hard surfaces. Conditions of Use 1. Compost socks may be used in areas requiring sediment or erosion control where runoff is in the form of sheet flow or in areas that silt fence is normally considered acceptable. Compost socks may also be used in sensitive environmental areas where migration of aquatic life, including turtles, salamanders and other aquatic life may be impeded by the used of silt fence. 2. Compost socks are not intended to treat substantial amounts of overland flow. However, compost socks may be subjected to some ponding and concentrated flows. If intended primarily as a filtration device, the socks should be sized and placed so that flows do not overtop the socks. 3. For purposes of long term sediment control objectives, compost socks may be seeded at the time of installation to create an additional vegetated filtering component. Design and Installation Specifications 1. Compost socks shall be produced using a pneumatic blower hose or equivalent to fill a mesh tube with compost to create a uniform cross-section and berm density. 2. Socks shall be filled so they are firmly – packed yet flexible. Upon initial filling, the socks shall be filled to have a round cross-section. Once placed on the ground, it is recommended to apply weight to the sock to improve contact with the underlying surface. This may cause the sock to assume an oval shape. 3. Compost socks shall be a minimum of 8 inches in diameter. Larger diameter socks are recommended for areas where ponding is expected behind the sock. 4. Compost socks shall not be used on slopes greater than 2H:1V. 5. Compost shall meet criteria in Reference Section 11-C of the SWDM, except for the particle size distribution (see Bullet 7). 6. Compost shall be obtained from a supplier meeting the requirements in Reference Section 11-C. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-40 7. Compost particle size distribution shall be as follows: 99% passing a 1-inch sieve, 90% passing a 3/4-inch sieve and a minimum of 70% greater than the 3/8-inch sieve. A total of 98% shall not exceed 3 inches in length. 8. In order to prevent water from flowing around the ends of compost socks, the ends must be pointed upslope so the ends of the socks are at a higher elevation than the remainder of the sock. Maintenance Standards 1. Compost socks shall be regularly inspected to make sure the mesh tube remains undamaged, the socks retain their shape, and allow adequate flow through of surface water. If the mesh tube is torn, it shall be repaired using twine, zip-ties, or wire. Large sections of damaged socks must be replaced. Any damage must be repaired immediately upon discovery of damage. 2. When the sock is no longer needed, the socks shall be cut open and the compost dispersed to be incorporated into the soil or left on top of the soil for final seeding to occur. The mesh material must be disposed of properly as solid waste. If spills of oil, antifreeze, hydraulic fluid, or other equipment fluids have occurred that have saturated the sock, the compost must be disposed of properly as a waste. 3. Sediment must be removed when sediment accumulations are within 3 inches of the top of the sock. D.2.1.4 TRAFFIC AREA STABILIZATION Unsurfaced entrances, roads, and parking areas used by construction traffic shall be stabilized to minimize erosion and tracking of sediment off site. Stabilized construction entrances shall be installed as the first step in clearing and grading. At the City’s discretion, road and parking area stabilization is not required during the dry season (unless dust is a concern) or if the site is underlain by coarse-grained soils. Roads and parking areas shall be stabilized immediately after initial grading. Purpose: The purpose of traffic area stabilization is to reduce the amount of sediment transported off site by construction vehicles and to reduce the erosion of areas disturbed by vehicle traffic. Sediment transported off site onto paved streets is a significant problem because it is difficult to effectively remove, and any sediment not removed ends up in the drainage system. Additionally, sediment on public right-of- way can pose a serious traffic hazard. Construction road and parking area stabilization is important because the combination of wet soil and heavy equipment traffic typically forms a slurry of easily erodible mud. Finally, stabilization also is an excellent form of dust control in the summer months. When to Install: The construction entrance is to be installed as the first step in clearing and grading. Construction road stabilization shall occur immediately after initial grading of the construction roads and parking areas. Measures to Use: There are two types of traffic area stabilization: (1) a stabilized construction entrance and (2) construction road/parking area stabilization. Both measures must be used as specified under “Conditions of Use” for each measure. D.2.1.4.1 STABILIZED CONSTRUCTION ENTRANCE Code: CE Symbol: Purpose Construction entrances are stabilized to reduce the amount of sediment transported onto paved roads by motor vehicles or runoff by constructing a stabilized pad of quarry spalls at entrances to construction sites. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-41 Conditions of Use Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within 1,000 feet of the site. Access and exits shall be limited to one route if possible, or two for linear projects such as roadway where more than one access/exit is necessary for maneuvering large equipment. For residential construction provide stabilized construction entrances for each residence in addition to the main subdivision entrance. Stabilized surfaces shall be of sufficient length/width to provide vehicle access/parking, based on lot size/configuration. Design and Installation Specifications 1. See Figure D.2.1.4.A for details. 2. A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4632) 200 lbs min. Grab Tensile Elongation (ASTM D4632) 30% max.(woven) Puncture Strength (ASTM D6241) 495 lbs min. AOS (ASTM D4751) 20–45 (U.S. standard sieve size) 3. Do not use crushed concrete, cement, or calcium chloride for construction entrance stabilization because these products raise pH levels in stormwater and concrete discharge to surface waters of the State is prohibited. 4. Hog fuel (wood based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. The effectiveness of hog fuel is highly variable, but it has been used successfully on many sites. It generally requires more maintenance than quarry spalls. Hog fuel is not recommended for entrance stabilization in urban areas. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause difficulties with compaction. 5. Fencing (see Section D.2.1.1) shall be installed as necessary to restrict traffic to the construction entrance. 6. Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance Standards 1. Quarry spalls (or hog fuel) shall be added if the pad is no longer in accordance with the specifications. 2. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. If washing is used, it shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. 3. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled. Wash water must be pumped back onto the site and cannot discharge to systems tributary to surface waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-42 4. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. 5. If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see Section D.2.1.1) shall be installed to control traffic. FIGURE D.2.1.4.A SCHEMATIC REPRESENTATION OF A STABILIZED CONSTRUCTION ENTRANCE D.2.1.4.2 CONSTRUCTION ROAD/PARKING AREA STABILIZATION Code: CRS Symbol: Purpose Stabilizing subdivision roads, parking areas and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use 1. Roads or parking areas shall be stabilized wherever they are constructed, whether permanent or temporary, for use by construction traffic. 2. Fencing (see Section D.2.1.1) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and Installation Specifications 1. A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or PER KING COUNTY ROAD DESIGN AND CONSTRUCTION STANDARDS (KCRDCS), DRIVEWAYS SHALL BE PAVED TO EDGE OF R-O-W PRIOR TO INSTALLATION OF THE CONSTRUCTION ENTRANCE TO AVOID DAMAGING OF THE ROADWAY. IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD. 12" MIN. THICKNESS PROVIDE FULL WIDTH OF INGRESS/EGRESS AREA IF A ROADSIDE DITCH IS PRESENT, INSTALL DRIVEWAY CULVERT PER KCRDCS GEOTEXTILE 4"- 8" QUARRY SPALLS R=25' MIN. 100' MIN. E X I S T I N G R O A D 1 5' M I N . NOTES: D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-43 calcium chloride for soil stabilization. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. Note: If the area will be used for permanent road or parking installation later in the project, the subgrade will be subject to inspection. 2. Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain transversely. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super-elevated section. Drainage ditches shall be designed in accordance with the standards given in Section D.2.1.6.4 and directed to a sediment pond or trap. 3. Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet-flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include vegetated wetlands. If runoff is allowed to sheet flow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. 4. In order to control construction traffic, the City may require that signs be erected on site informing construction personnel that vehicles, other than those performing clearing and grading, are restricted to stabilized areas. 5. If construction roads do not adequately reduce trackout to adjacent property or roadways, a wheel wash system will be required. Maintenance Standards Crushed rock, gravel base, hog fuel, etc., shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. D.2.1.4.3 WHEEL WASH Code: WW Symbol: Purpose Wheel wash systems reduce the amount of sediment transported onto paved roadways and into surface water systems by construction vehicles. Conditions of Use When a stabilized construction entrance is not preventing sediment from being tracked onto pavement: Wheel washing is generally an effective erosion and sediment control method and BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck wheels and undercarriage can run unimpeded into the street. Pressure washing combined with an adequately sized and properly surfaced wash pad with direct drainage discharge to a large 10-foot x 10-foot sump can be very effective. Design and Installation Specifications A suggested detail is shown in Figure D.2.1.4.B. 1. A minimum of 6 inches of asphalt treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash area. 2. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will work well to test clearance. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-44 3. Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the truck tongues with water. 4. Midpoint spray nozzles are only needed in very muddy conditions. 5. Wheel wash systems should be designed with a small grade change, 6 to 12 inches for a 10-foot-wide pond, to allow sediment to flow to the low side of the pond and to help prevent re-suspension of sediment. 6. A drainpipe with a 2- to 3-foot riser should be installed on the low side of the wheel wash pond to allow for easy cleaning and refilling. Polymers may be used to promote coagulation and flocculation in a closed-loop system. 7. Polyacrylamide (PAM) added to the wheel washwater at a rate of 0.25 to 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water truck, the same truck may be used to change the washwater. Maintenance Standards 1. The wheel wash should start out each day with clean, fresh water. 2. The washwater should be changed a minimum of once per day. On large earthwork jobs where more than 10 to 20 trucks per hour are expected, the washwater will need to be changed more often. 3. Wheel wash or tire bath wastewater shall be discharged to a separate onsite treatment system that prevents discharge to surface water, or to the sanitary sewer system with proper approval and/or permits from King County and the City of Renton. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-45 FIGURE D.2.1.4.B WHEEL WASH AND PAVED CONSTRUCTION ENTRANCE 2% SLOPE 15'15'20'15'50' 18' 12' 3' 5' BUILD 8'x8' SUMP TO ACCOMODATE CLEANING BY TRACKHOE. SECTION A-A NTS 8'x8' SUMP, SEE NOTE LOCATE INVERT OF TOP PIPE 1' ABOVE BOTTOM OF WHEEL WASH DRAIN PIPE 1:1 SLOPE WATER LEVEL ELEVATION VIEW NTS PLAN VIEW NTS 6" SLEEVE CURB ASPHALT CURB ON THE LOW ROAD SIDE TO DIRECT WATER BACK TO POND 6" ATB CONSTRUCTION ENTRANCE 1-1/2" SCHEDULE 40 FOR SPRAYERS 2% SLOPE MIDPOINT SPRAY NOZZLES, IF NEEDED 3" TRASH PUMP WITH FLOATS ON SUCTION HOSE 2" SCHEDULE 40 6" SLEEVE UNDER ROAD 8'x8' SUMP WITH 5' OF CATCH 6" SEWER PIPE WITH BUTTERFLY VALVES 1:1 SLOPE A A 5:1 SLOPE 5:1 SLOPE 15' ATB APRON TO PROTECT GROUND FROM SPLASHING WATER BALL VALVES NOTE: SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-52 D.2.1.5.3 STORM DRAIN INLET PROTECTION Code: FFP or CBI or CBP Symbol: or or Purpose Storm drain inlets are protected to prevent coarse sediment from entering storm drainage systems. Temporary devices around storm drains assist in improving the quality of water discharged to inlets or catch basins by ponding sediment-laden water. These devices are effective only for relatively small drainage areas. Conditions of Use 1. Protection shall be provided for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. 2. Inlet protection may be used anywhere at the applicant’s discretion to protect the drainage system. This will, however, require more maintenance, and it is highly likely that the drainage system will still require some cleaning. 3. The contributing drainage area must not be larger than one acre. Design and Installation Specifications 1. There are many options for protecting storm drain inlets. Two commonly used options are filter fabric protection and catch basin inserts. Filter fabric protection (see Figure D.2.1.5.E) is filter fabric (geotextile) placed over the grate. This method is generally very ineffective and requires intense maintenance efforts. Therefore, filter fabric protection is not allowed in the City of Renton. Catch basin inserts (see Figure D.2.1.5.F) are manufactured devices that nest inside a catch basin. This method also requires a high frequency of maintenance to be effective. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-53 Trapping sediment in the catch basins is unlikely to improve the water quality of runoff if it is treated in a pond or trap because the coarse particles that are trapped at the catch basin settle out very quickly in the pond or trap. Catch basin protection normally only improves water quality where there is no treatment facility downstream. In these circumstances, catch basin protection is an important last line of defense. It is not, however, a substitute for preventing erosion. 2. It is sometimes possible to construct a small sump around the catch basin before final surfacing of the road. This is allowed because it can be a very effective method of sediment control. 3. Block and gravel filters, gravel and wire mesh filter barriers, and bag barriers filled with various filtering media placed around catch basins can be effective when the drainage area is 1 acre or less and flows do not exceed 0.5 cfs. It is necessary to allow for overtopping to prevent flooding. Many manufacturers have various inlet protection filters that are very effective in keeping sediment-laden water from entering the storm drainage system. The following are examples of a few common methods. a) Block and gravel filters (Figure D.2.1.5.G) are a barrier formed around an inlet with standard concrete block and gravel, installed as follows: Height is 1 to 2 feet above the inlet. Recess the first row of blocks 2 inches into the ground for stability. Support subsequent rows by placing a 2x4 through the concrete block opening. Do not use mortar. Lay some blocks in the bottom row on their side for dewatering the pooled water. Place cloth or mesh with ½ inch openings over all block openings. Place gravel below the top of blocks on slopes of 2:1 or flatter. An alternate design is a gravel donut. b) Gravel and wire mesh filters consist of a gravel barrier placed over the top of an inlet. This structure generally does not provide overflow. Install as follows: Cloth or comparable wire mesh with ½ inch openings is placed over inlet. Coarse aggregate covers the cloth or mesh. Height/depth of gravel should be 1 foot or more, 18 inches wider than inlet on all sides. c) Curb inlet protection with a wooden weir is a barrier formed around an inlet with a wooden frame and gravel, installed as follows: Construct a frame and attach wire mesh (½ inch openings) and filter fabric to the frame. Pile coarse washed aggregate against the wire/fabric. Place weight on frame anchors. d) Curb and gutter sediment barriers (Figure D.2.1.5.H) consist of sandbags or rock berms (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape, installed as follows: Bags of either burlap or woven geotextile fabric, filled with a variety of media such as gravel, wood chips, compost or sand stacked tightly allows water to pond and allows sediment to separate from runoff. Leave a “one bag gap” in the top row of the barrier to provide a spillway for overflow. Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 x 3 and at least 2 feet from the inlet. Construct a horseshoe shaped sedimentation trap on the outside of the berm to sediment trap standards for protecting a culvert inlet. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-54 4. Excavated drop inlet sediment traps are appropriate where relatively heavy flows are expected and overflow capability is needed. If emergency overflow is provided, additional end-of-pipe treatment may be required. Excavated drop inlets consist of an excavated impoundment area around a storm drain. Sediment settles out of the stormwater prior to enter the drain. Install according to the following specifications: a) The impoundment area should have a depth of 1 to 2 feet measured from the crest of the inlet structure. b) Side slopes of the excavated area must be no steeper than 2:1. c) Minimum volume of the excavated area should be 35 cubic yards. d) Install provisions for draining the area to prevent standing water problems. e) Keep the area clear of debris. f) Weep holes may be drilled into the side of the inlet. g) Protect weep holes with wire mesh and washed aggregate. h) Weep holes must be sealed when removing and stabilizing excavated area. i) A temporary dike may be necessary on the down slope side of the structure to prevent bypass flow. Maintenance Standards 1. Any accumulated sediment on or around inlet protection shall be removed immediately. Sediment shall not be removed with water, and all sediment must be disposed of as fill on site or hauled off site. 2. Any sediment in the catch basin insert shall be removed when the sediment has filled one-third of the available storage. The filter media for the insert shall be cleaned or replaced at least monthly. 3. Regular maintenance is critical for all forms of catch basin/inlet protection. Unlike many forms of protection that fail gradually, catch basin protection will fail suddenly and completely if not maintained properly. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-55 FIGURE D.2.1.5.E FILTER FABRIC PROTECTION (NOT ALLOWED) FIGURE D.2.1.5.F CATCH BASIN INSERT CATCH BASIN NOTE: ONLY TO BE USED WHERE PONDING OF WATER ABOVE THE CATCH BASIN WILL NOT CAUSE TRAFFIC PROBLEMS AND WHERE OVERFLOW WILL NOT RESULT IN EROSION OF SLOPES. GRATESTANDARD STRENGTH FILTER FABRIC NOTE: THIS DETAIL IS ONLY SCHEMATIC. ANY INSERT IS ALLOWED THAT HAS: A MIN. 0.5 C.F. OF STORAGE,THE MEANS TO DEWATER THE STORED SEDIMENT,AN OVERFLOW, ANDCAN BE EASILY MAINTAINED. OVERFLOW GRATECATCH BASIN POROUS BOTTOM SOLID WALLS FILTER MEDIA FOR DEWATERING SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-56 FIGURE D.2.1.5.G BLOCK AND GRAVEL CURB INLET PROTECTION 1. USE BLOCK AND GRAVEL TYPE SEDIMENT BARRIER WHEN CURB INLET IS LOCATED IN GENTLY SLOPING SEGMENT, WHERE WATER CAN POND AND ALLOW SEDIMENT TO SEPARATE FROM RUNOFF. 2. BARRIER SHALL ALLOW FOR OVERFLOW FROM SEVERE STORM EVENT. 3. INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENT AND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. 2x4 WOOD STUD OVERFLOW WATER A A PLAN VIEW NTS SECTION A-A NTS BLOCK AND GRAVEL CURB INLET PROTECTION NTS CATCH BASIN COVER CURB INLET CONCRETE BLOCKS CATCH BASIN COVER CURB INLET CATCH BASIN BACK OF SIDEWALK CURB FACE 3/4" DRAIN GRAVEL (20 mm) WIRE SCREEN OR FILTER FABRIC POND HEIGHT WIRE SCREEN OR FILTER FABRIC 2x4 WOOD STUD (100x50 TIMBER STUD) 3/4" DRAIN GRAVEL (20 mm) NOTES: D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-57 FIGURE D.2.1.5.H CURB AND GUTTER BARRIER PROTECTION RUNOFF RUNOFF SPILLWAY 1. PLACE CURB-TYPE SEDIMENT BARRIERS ON GENTLY SLOPING STREET SEGMENTS, WHERE WATER CAN POND AND ALLOW SEDIMENT TO SEPARATE FROM RUNOFF. 2. SANDBAGS OF EITHER BURLAP OR WOVEN GEOTEXTILE FABRIC ARE FILLED WITH GRAVEL, LAYERED AND PACKED TIGHTLY. 3. LEAVE A ONE-SANDBAG GAP IN THE TOP ROW TO PROVIDE A SPILLWAY FOR OVERFLOW. 4. INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENT AND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. GRAVEL FILLED SANDBAGS STACKED TIGHTLY DRAIN GRATE GUTTER CURB FACE CURB INLET SANDBAGS TO OVERLAP ONTO CURB BACK OF SIDEWALK PLAN VIEW NTS CURB AND GUTTER BARRIER NTS NOTES: SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-58 D.2.1.6 SURFACE WATER COLLECTION All surface water from disturbed areas shall be intercepted, conveyed to a sediment pond or trap, and discharged downslope of any disturbed areas. An exception is for areas at the perimeter of the site with drainage areas small enough to be treated solely with perimeter protection (see Section D.2.1.3). Also, if the soils and topography are such that no offsite discharge of surface water is anticipated up to and including the developed 2-year runoff event, surface water controls are not required. A 10-year approved model 15-minute peak flow shall be used for sizing surface water controls if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection (see the introduction to Section D.2.1.5). At the City’s discretion, sites may be worked during the dry season without surface water controls, if there is some other form of protection of surface waters, such as a 100-foot forested buffer between the disturbed areas and adjacent surface waters. Significant sources of upslope surface water that drain onto disturbed areas shall be intercepted and conveyed to a stabilized discharge point downslope of the disturbed areas. Surface water controls shall be installed concurrently with rough grading. Purpose: The purpose of surface water control is to collect and convey surface water so that erosion is minimized, and runoff from disturbed areas is treated by a sediment pond or trap. Surface water control essentially consists of three elements: 1. Interception of runoff on and above slopes 2. Conveyance of the runoff to a sediment pond or trap (if the runoff was collected from a disturbed area) 3. Release of the runoff downslope of any disturbed areas. When to Install: Surface water controls shall be constructed during the initial grading of an area and must be in place before there is any opportunity for storm runoff to cause erosion. Measures to Install: Interceptor dikes/swales intercept runoff, ditches and pipe slope drains convey the runoff, and riprap or level spreaders help release the runoff in a non-erosive manner. Each measure is to be used under different circumstances so there is very little overlap. However, the two options for releasing water in a non-erosive manner, outlet protection and level spreaders, can be somewhat interchangeable. See Figure D.2.1.6.A for a schematic drawing demonstrating the use of these measures. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-59 FIGURE D.2.1.6.A SKETCH PLAN OF SURFACE WATER CONTROLS D.2.1.6.1 INTERCEPTOR DIKE AND SWALE Code: ID or IS Symbol: or Purpose Interceptor dikes and swales intercept storm runoff from drainage areas on or above disturbed slopes and convey it to a sediment pond or trap. They may also be used to intercept runoff from undisturbed areas and convey the runoff to a point below any exposed soils. Interception of surface water reduces the possibility of slope erosion. Interceptor dikes and swales differ from ditches (see Section D.2.1.6.4) in that they are intended to convey smaller flows along low-gradient drainage ways to larger conveyance systems such as ditches or pipe slope drains. Conditions of Use Interceptor dikes and swales are required in the following situations: 1. At the top of all slopes in excess of 3H:1V and with more than 20 feet of vertical relief. 2. At intervals on any slope that exceeds the dimensions specified in this section for the horizontal spacing of dikes and swales. Design and Installation Specifications 1. See Figure D.2.1.6.B for details of an interceptor dike and Figure D.2.1.6.C for an interceptor swale. 2. Interceptor dikes and swales shall be spaced horizontally as follows: Average Slope Slope Percent Flowpath Length 20H:1V or less 3–5% 300 feet (10 to 20)H:1V 5–10% 200 feet (4 to 10)H:1V 10–25% 100 feet (2 to 4)H:1V 25–50% 50 feet INTERCEPTOR DIKE TOP OF SLOPE TOE OF SLOPE OUTLET PROTECTION DITCH SEDIMENT POND SILT FENCE STREAM PIPE SLOPE DRAIN FLOW ID PD ID OP DI SP SF SF OP SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-60 3. For slopes steeper than 2H:1V with more than 10 feet of vertical relief, benches may be constructed or closer spaced interceptor dikes or swales may be used. Whichever measure is chosen, the spacing and capacity of the measures must be designed by the engineer and the design must include provisions for effectively intercepting the high velocity runoff associated with steep slopes. 4. If the dike or swale intercepts runoff from disturbed areas, it shall discharge to a stable conveyance system that routes the runoff to a sediment pond or trap (see Section D.2.1.5). If the dike or swale intercepts runoff that originates from undisturbed areas, it shall discharge to a stable conveyance system that routes the runoff downslope of any disturbed areas and releases the water at a stabilized outlet. 5. Construction traffic over temporary dikes and swales shall be minimized. Maintenance Standards 1. Damage resulting from runoff or construction activity shall be repaired immediately. 2. If the facilities do not regularly retain storm runoff, the capacity and/or frequency of the dikes/swales shall be increased. FIGURE D.2.1.6.B INTERCEPTOR DIKE FIGURE D.2.1.6.C INTERCEPTOR SWALE DIKE SPACING DEPENDS ON SLOPE GRADIENT 2' MIN.18" MIN. 2 MAX. 12 MAX. 1 DIKE MATERIAL COMPACTED 90% MODIFIED PROCTOR SWALE SPACING DEPENDS ON SLOPE GRADIENT 2' MIN. 1' MIN. LEVEL BOTTOM 2:1 MAX. SLOPE D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-63 D.2.1.6.4 DITCHES Code: DI Symbol: Purpose Ditches convey intercepted runoff from disturbed areas to and from sediment ponds or traps. They also convey runoff intercepted from undisturbed areas around the site to a non-erosive discharge point. Conditions of Use Ditches may be used anywhere that concentrated runoff is to be conveyed on or around the construction site. Temporary pipe systems may also be used to convey runoff. Design and Installation Specifications 1. Channels and ditches shall be sized to accommodate the developed condition 10-year approved model 15-minute peak flow with 0.5 feet of freeboard. If no hydrologic analysis is required for the site, the Rational Method may be used (see Section 3.2.1 of the SWDM). 2. See SWDM Section 4.4.1 for open-channel design requirements. 3. The only exception to the requirements of SWDM Section 4.4.1 is the use of check dams, rather than grass lining, for channels in which the design flow velocity does not exceed 5 fps. See Figure D.2.1.6.E for details on check dam installation. Maintenance Standards 1. Any sediment deposition of more than 0.5 feet shall be removed so that the channel is restored to its design capacity. 2. If the channel capacity is insufficient for the design flow, it must be determined whether the problem is local (e.g., a constriction or bend) or the channel is under-designed. If the problem is local, the channel capacity must be increased through construction of a berm(s) or by excavation. If the problem is under-design, the design engineer shall be notified and the channel redesigned to a more conservative standard to be approved by the City of Renton. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-64 3. The channel shall be examined for signs of scouring and erosion of the bed and banks. If scouring or erosion has occurred, affected areas shall be protected by riprap or an erosion control blanket or net. FIGURE D.2.1.6.E CHECK DAMS D.2.1.6.5 OUTLET PROTECTION Code: OP Symbol: Purpose Outlet protection prevents scour at conveyance outlets. Conditions of Use Outlet protection is required at the outlets of all ponds, pipes, ditches, or other approved conveyances, and where runoff is conveyed to a natural or manmade drainage feature such as a stream, wetland, lake, or ditch. Design and Installation Specifications For the standard pipe slope drains in Section D.2.1.6.2 and other smaller conveyance systems, the standard rock pad (6 feet by 8 feet) made of 1-foot thick quarry spall is adequate. For all other outlets, the outlet protection shall meet the requirements of the “Outfalls” section of Core Requirement #4 and Section 4.2.2 of the SWDM. Maintenance Standards for Outlet Protection If there is scour at the outlet, the eroded area shall be protected with more conservative measures proposed by the design engineer and approved by the City of Renton. 6" MIN. ROCK MUST COMPLETELY COVER THE BOTTOM AND SIDES OF THE DITCH 24" MIN. 2H:1V SLOPES L 2"- 4" ROCKBA L=THE DISTANCE SUCH THAT POINTS A AND B ARE OF EQUAL ELEVATION CROSS SECTION CHECK DAM SPACING SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-66 D.2.1.7 DEWATERING CONTROL Any runoff generated by dewatering shall be treated through construction of a sediment trap (Section D.2.1.5.1) when there is sufficient space or by releasing the water to a well vegetated, gently sloping area. Since pumps are used for dewatering, it may be possible to pump the sediment-laden water well away from the surface water so that vegetation can be more effectively utilized for treatment. Discharge of sediment-laden water from dewatering activities to surface and storm waters is prohibited. If dewatering occurs from areas where the water has come in contact with new concrete, such as tanks, vaults, or foundations, the pH of the water must be monitored and must be neutralized prior to discharge. Clean non-turbid dewatering water, such as well point ground water can be discharged to systems tributary to, or directly to surface waters provided the flows are controlled so no erosion or flooding occurs. Clean water must not be routed through a stormwater sediment pond. Highly turbid or contaminated dewatering water must be handled separately from stormwater. Purpose: To prevent the untreated discharge of sediment-laden water from dewatering of utilities, excavated areas, foundations, etc. When to Install: Dewatering control measures shall be used whenever there is a potential for runoff from dewatering of utilities, excavations, foundations, etc. Measures to install: 1. Foundation, vault, excavation, and trench dewatering water that has similar characteristics to stormwater runoff at the site shall be discharged into a controlled conveyance system prior to discharge to a sediment trap or sediment pond. Foundation and trench dewatering water that has similar characteristics to stormwater runoff at the site must be disposed of through one of the following options depending on site constraints: a) Infiltration, b) Transport offsite in a vehicle, such as a vacuum flush truck, for legal disposal in a manner that does not pollute surface waters, D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-67 c) Discharge to the sanitary sewer discharge with approval from King County and the City of Renton if there is no other option, or d) Use of a sedimentation bag with outfall to a ditch or swale for small volumes of localized dewatering. 2. Clean, non-turbid dewatering water, such as well-point ground water, may be discharged via stable conveyance to systems tributary to surface waters, provided the dewatering flow does not cause erosion or flooding of receiving waters. 3. Highly turbid or contaminated dewatering water (high pH or other) shall be handled separately from stormwater. See Section D.2.2 , SWPPS Measures. D.2.1.8 DUST CONTROL Preventative measures to minimize the wind transport of soil shall be taken when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources or adjacent properties. Purpose: To prevent wind transport of dust from exposed soil surfaces onto roadways, drainage ways, and surface waters. When to Install: Dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted. Dust control measures may consist of chemical, structural, or mechanical methods. Measures to Install: Water is the most common dust control (or palliative) used in the area. When using water for dust control, the exposed soils shall be sprayed until wet, but runoff shall not be generated by spraying. Calcium chloride, Magnesium chloride, Lignin derivatives, Tree Resin Emulsions, and Synthetic Polymer Emulsions may also be used for dust control. Exposed areas shall be re-sprayed as needed. Oil shall not be used for dust control. The following table lists many common dust control measures. Some of the measures are not recommended for use in the City and must have prior approval prior to use from the CED inspector assigned to specific projects. TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Water -Most commonly used practice -Evaporates quickly -Lasts less than 1 day For all liquid agents: -Blade a small surface -Crown or slope surface to avoid ponding -Compact soils if needed -Uniformly pre-wet at 0.03 – 0.3 gal/sq yd -Apply solution under pressure. Overlap solution 6 – 12 inches -Allow treated area to cure 0 – 4 hours -Compact area after curing -Apply second treatment before first treatment becomes ineffective 0.125 gal/sq yd every 20 to 30 minutes Salts Calcium Chloride (CaCl) -Restricts evaporation -Lasts 6–12 months -Can be corrosive -Less effective in low humidity -Can build up in soils and leach by rain Apply 38% solution at 1.21L/m2 (0.27 gal/yd2) or as loose dry granules per manufacturer SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-68 TABLE D.2.1.8.A DUST CONTROL MEASURES Method Considerations Site Preparation Recommended Application Rate Magnesium Chloride (MgCl) -Restricts evaporation -Works at higher temperatures and lower humidity than CaCl -May be more costly than CaCl Apply 26 – 32% solution at 2.3 L/m2 (0.5 gal/yd2) Sodium Chloride (NaCl) -Effective over smaller range of conditions -Less expensive -Can be corrosive -Less effective in low humidity Per Manufacturer Silicates -Generally expensive -Available in small quantities -Require Second application Surfactants -High evaporation rates -Effective for short time periods -Must apply frequently Copolymers -Forms semi-permeable transparent crust -Resists ultraviolet radiation and moisture induced breakdown -Last 1 to 2 years 750 – 940 L/ha (80 – 100 gal/ac) Petroleum Products -Used oil is prohibited as a dust control method -Bind soil particles -May hinder foliage growth -Environmental and aesthetic concerns -Higher cost Use 57 – 63% resins as base. Apply at 750 – 940 L/ha (80–100 gal/ac) Lignin Sulfonate -Paper industry waste product -Acts as dispersing agent -Best in dry climates -Can be slippery -Will decrease Dissolved Oxygen in waterways therefore cannot be used adjacent to surface water systems Loosen surface 25–50 mm (1–2 inches) Need 4–8% fines Vegetable Oils -Coat grains of soils, so limited binding ability -May become brittle -Limited availability Per Manufacturer Spray on Adhesives -Available as organic or synthetic -Effective on dry, hard soils -Forms a crust -Can last 3 to 4 years Per Manufacturer D.2.1.9 FLOW CONTROL Surface water from disturbed areas must be routed through the project’s onsite flow control facility or other provisions must made to prevent increases in the existing site conditions 2-year and 10-year runoff peaks discharging from the project site during construction. Purpose: The purpose of surface water flow control is to mitigate increases in runoff peaks that occur during construction as a result of clearing vegetation, compacting the soil, and adding impervious surface. Such increases can cause or aggravate downstream flooding and erosion. D.2.1 ESC MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-69 When to Install: Surface water flow control shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct the surface water flow control facilities. Measures to Use: The project’s onsite flow control facility or other equivalent storage facility that meets the peak-matching performance criteria stated above. D.2.1.10 PROTECT EXISTING AND PROPOSED STORMWATER FACILITIES AND ON-SITE BMPS Protection measures shall be applied/installed and maintained so as to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed stormwater facilities and on-site BMPs for the project. Adverse impacts can prompt the requirement to restore or replace affected stormwater facilities and on-site BMPs. Purpose: The purpose of protecting existing and proposed stormwater facility and on-site BMP areas is to avoid sedimentation and soil compaction that would adversely affect infiltration, and also avoid contamination by other pollutants. When to Install: Stormwater facility and on-site BMP area protection shall be installed or otherwise provided prior to any clearing and/or grading of the site, except that required to construct stormwater facilities and on-site BMPs. Measures to Use: 1. Protect all stormwater facilities and on-site BMPs and proposed stormwater facility and on-site BMP footprints from sedimentation through installation and maintenance of erosion and sediment control BMPs on portions of the site that drain into the BMPs/facilities. 2. Stormwater facilities and on-site BMPs shall be restored to their fully functioning condition if they accumulate sediment during construction. Restoring the stormwater facilities and on-site BMPs shall include, at a minimum, removal of sediment and any sediment-laden bioretention soils, and replacing the removed soils with soils meeting the design specification. Replacement with a new fully- functioning stormwater facility and/or on-site BMP may be required if restoration to the fully- functioning condition can’t be accomplished. 3. Prevent compacting Bioretention BMPs/facilities by excluding construction equipment and foot traffic. Protect completed lawn and landscaped areas from compaction due to construction equipment. 4. Control erosion and avoid introducing sediment from surrounding land uses onto permeable pavement BMPs. Do not allow muddy construction equipment on the base material or pavement. Do not allow sediment-laden runoff onto permeable pavements. 5. Permeable pavement BMPs fouled with sediments or no longer passing an initial infiltration text must be cleaned using procedures from Appendix A or the manufacturer’s procedures. 6. Keep all heavy equipment off existing soils under stormwater facilities and on-site BMPs that have been excavated to final grade to retain the infiltration rate of the soils. D.2.1.11 MAINTAIN PROTECTIVE BMPS Protection measures shall be maintained to ensure continued performance of their intended function, to prevent adverse impacts to existing stormwater facilities and on-site BMPs and areas of proposed BMPs/facilities, and protect other disturbed areas of the project. Purpose: The purpose of maintaining protective BMPs is to provide continuous erosion and sediment control protection throughout the life of the project, and avoid sedimentation, soil compaction and contamination by other pollutants that would adversely affect infiltration and surface runoff. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-70 When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Measures to Use: 1. Maintain and repair all temporary and permanent erosion and sediment control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Remove all temporary erosion and sediment control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. 3. Provide protection to all stormwater facilities and on-site BMPs installed for the permanent control of stormwater from sediment and compaction. All stormwater facilities and on-site BMPs that are to remain in place following completion of construction shall be examined and placed in full operating conditions. If sediment enters the stormwater facilities and/or on-site BMPs during construction, it shall be removed and the stormwater facility and on-site BMP shall be returned to the conditions specified in the construction documents or as required for full stormwater facility and on-site BMP replacement. 4. Remove or stabilize trapped sediment on site. Permanently stabilize disturbed soil resulting from removal of erosion and sediment control BMPs or vegetation. D.2.1.12 MANAGE THE PROJECT Coordination and timing of site development activities relative to ESC concerns (Section D.2.4), and timely inspection, maintenance and update of protective measures (Section D.2.3) are necessary to effectively manage the project and ensure the success of protective ESC and SWPPS design and implementation. Projects shall assign a qualified CSWPP Supervisor (Section D.2.3.1) to be the primary contact for ESC and SWPPP issues and reporting, coordination with subcontractors and implementation of the CSWPP plan as a whole. Measures to Use: 1. Phase development projects to the maximum degree practicable and take into account seasonal work limits. 2. Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Conduct site inspections and monitoring in accordance with the Construction Stormwater General Permit and City requirements. 3. Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP in accordance with the Construction Stormwater General Permit and City requirements. 4. Projects that disturb one or more acres must have, site inspections conducted by a Certified Erosion and Sediment Control Lead (CESCL) (see Section D.2.3.1). Project sites less than one acre (not part of a larger common plan of development or sale) may have a person without CESCL certification conduct inspections. By the initiation of construction, the SWPPP must identify the CESCL or inspector, who shall be present onsite or on-call at all times. The CESCL or inspector (project sites less than one acre) must have the skills to assess the: Site conditions and construction activities that could impact the quality of stormwater. Effectiveness of erosion and sediment control measures used to control the quality of stormwater discharges. The CESCL or inspector must examine stormwater visually for the presence of suspended sediment, turbidity, discoloration, and oil sheen. They must evaluate the effectiveness of BMPs and determine if it is necessary to install, maintain, or repair BMPs to improve the quality of stormwater discharges. D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-71 Based on the results of the inspection, construction site operators must correct the problems identified by: Reviewing the SWPPP for compliance with all construction SWPPP elements and making appropriate revisions within 7 days of the inspection. Immediately beginning the process of fully implementing and maintaining appropriate source control and/or treatment BMPs as soon as possible, addressing the problems not later than within 10 days of the inspection. If installation of necessary treatment BMPs is not feasible within 10 days, the construction site operator may request an extension within the initial 10-day response period. Documenting BMP implementation and maintenance in the site log book (applies only to sites that have coverage under the Construction Stormwater General Permit). The CESCL or inspector must inspect all areas disturbed by construction activities, all BMPs, and all stormwater discharge points at least once every calendar week and within 24 hours of any discharge from the site. (For purposes of this condition, individual discharge events that last more than one day do not require daily inspections. For example, if a stormwater pond discharges continuously over the course of a week, only one inspection is required that week.) The CESCL or inspector may reduce the inspection frequency for temporary stabilized, inactive sites to once every calendar month. D.2.2 SWPPS MEASURES This section details the SWPPS measures that are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses from construction-related activities such as materials delivery and storage, onsite equipment fueling and maintenance, demolition of existing buildings and disposition of demolition materials and other waste, and concrete handling, washout and disposal. These SWPPS measures represent Best Management Practices (BMPs)8 for the control of pollutant drips and spills as well as other impacts related to construction such as increased pH in concrete construction and handling activities. Compliance with each of the SWPPS measures, and with any project- specific control measures, to the extent applicable and necessary to meet the performance criteria in Section D.2.2, and compliance with the CSWPP implementation requirements in Section D.2.4, constitutes overall compliance with the City’s CSWPP Standards. Note: Additional measures shall be required by the City if the existing standards are insufficient to protect adjacent properties, drainage facilities, or water resources. The standards for each individual SWPPS measure are divided into four sections: 1. Purpose 2. Conditions of Use 3. Design and Installation Specifications 4. Maintenance Requirements. Note that the “Conditions of Use” always refers to site conditions. As site conditions change, SWPPS measures must be changed to remain in compliance with the requirements of this appendix. Whenever compliance with City SWPPS Standards is required, all of the following SWPPS measures must be considered for application to the project site as detailed in the following sections. The construction pollutant generating concerns addressed by the BMPs that follow include: Concrete handling, washout and disposal(specifically portland cement concrete) Sawcutting and surfacing activities Materials delivery, storage and containment 8 Best Management Practices (BMPs) means the best available and reasonable physical, structural, managerial, or behavioral activities, that when singly or in combination, eliminate or reduce the contamination of surface and/or ground waters. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-72 Filtration and chemical treatment of construction water to facilitate disposal or discharge to approved locations Reporting requirements and documentation availability for specific BMP processes Additionally, several of the ESC BMPs described in Section D.2.1 can be applicable to the SWPPS plan, e.g., use of cover, fencing and access protection to protect temporary materials storage locations. The applicant’s material supplier may be a resource (subject to City approval) for BMPs to address specific project applications or proposals. Conditions of approval on adjustments may also specify additional requirements for the SWPPS plan. D.2.2.1 CONCRETE HANDLING Purpose Concrete work can generate process water and slurry that contain fine particles and high pH, both of which can violate water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate concrete, concrete process water, and concrete slurry from entering waters of the state. Conditions of Use Any time concrete is used, utilize these management practices. Concrete construction projects include, but are not limited to, curbs, sidewalks, roads, bridges, foundations, floors, stormwater vaults, retaining walls, driveways and runways. Design and Installation Specifications 1. Ensure that washout of concrete trucks, chutes, pumps, and internals is performed at an approved off- site location or in designated concrete washout areas. Do not wash out concrete trucks, chutes, pumps, or internals onto the ground, or into storm drains, open ditches, streets, or streams. Refer to BMP D.2.2.2 for information on concrete washout areas. 2. Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. 3. Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas awaiting future concrete pours only. 4. Do not wash out to formed areas awaiting infiltration BMPs. 5. Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. 6. Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. 7. Contain washwater and leftover product in a lined container when no formed areas are available. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. 8. Always use forms or solid barriers for concrete pours, such as pilings, within 15-feet of surface waters. 9. Refer to BMPs D.2.2.7 and D.2.2.8 for pH adjustment requirements. 10. Refer to the Construction Stormwater General Permit for pH monitoring requirements if the project involves one of the following activities: Significant concrete work (greater than 1,000 cubic yards poured concrete or recycled concrete used over the life of a project). The use of engineered soils amended with (but not limited to) Portland cement-treated base, cement kiln dust or fly ash. Discharging stormwater to segments of water bodies on the 303(d) list (Category 5) for high pH. D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-73 Maintenance Standards Check containers for holes in the liner daily during concrete pours and repair the same day. D.2.2.2 CONCRETE WASHOUT AREA Purpose Prevent or reduce the discharge of pollutants to stormwater from concrete waste by conducting washout off-site, or performing onsite washout in a designated area to prevent pollutants from entering surface waters or ground water. Conditions of Use Concrete washout area best management practices are implemented on construction projects where: Concrete is used as a construction material It is not possible to dispose of all concrete wastewater and washout off-site (ready mix plant, etc.). Concrete trucks, pumpers, or other concrete coated equipment are washed onsite. Note: If less than 10 concrete trucks or pumpers need to be washed out onsite, the washwater may be disposed of in a formed area awaiting concrete or an upland disposal site where it will not contaminate surface or ground water. The upland disposal site shall be at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. Design and Installation Specifications Implementation The following steps will help reduce stormwater pollution from concrete wastes: 1. Perform washout of concrete trucks at an approved off-site location or in designated concrete washout areas only. 2. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. 3. Do not allow excess concrete to be dumped onsite, except in designated concrete washout areas. 4. Concrete washout areas may be prefabricated concrete washout containers, or self-installed structures (above-grade or below-grade). 5. Prefabricated containers are most resistant to damage and protect against spills and leaks. Companies may offer delivery service and provide regular maintenance and disposal of solid and liquid waste. 6. If self-installed concrete washout areas are used, below-grade structures are preferred over above- grade structures because they are less prone to spills and leaks. 7. Self-installed above-grade structures should only be used if excavation is not practical. Education 1. Discuss the concrete management techniques described in this BMP with the ready-mix concrete supplier before any deliveries are made. 2. Educate employees and subcontractors on the concrete waste management techniques described in this BMP. 3. Arrange for contractor’s superintendent or Certified Erosion and Sediment Control Lead (CESCL) to oversee and enforce concrete waste management procedures. 4. A sign should be installed adjacent to each temporary concrete washout facility to inform concrete equipment operators to utilize the proper facilities. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-74 Contracts Incorporate requirements for concrete waste management into concrete supplier and subcontractor agreements. Location and Placement 1. Locate washout area at least 50 feet from sensitive areas such as storm drains, open ditches, or water bodies, including wetlands. 2. Allow convenient access for concrete trucks, preferably near the area where the concrete is being poured. 3. If trucks need to leave a paved area to access washout, prevent track-out with a pad of rock or quarry spalls (see BMP D.2.1.4.2). These areas should be far enough away from other construction traffic to reduce the likelihood of accidental damage and spills. 4. The number of facilities you install should depend on the expected demand for storage capacity. 5. On large sites with extensive concrete work, washouts should be placed in multiple locations for ease of use by concrete truck drivers. On-Site Temporary Concrete Washout Facility, Transit Truck Washout Procedures: 1. Temporary concrete washout facilities shall be located a minimum of 50 feet from sensitive areas including storm drain inlets, open drainage facilities, and watercourses. (See Figures D.2.2.2.A, D.2.2.2.B, and D.2.2.2.C). 2. Concrete washout facilities shall be constructed and maintained in sufficient quantity and size to contain all liquid and concrete waste generated by washout operations. 3. Washout of concrete trucks shall be performed in designated areas only. 4. Concrete washout from concrete pumper bins can be washed into concrete pumper trucks and discharged into designated washout area or properly disposed of off-site. 5. Once concrete wastes are washed into the designated area and allowed to harden, the concrete should be broken up, removed, and disposed of per applicable solid waste regulations. Dispose of hardened concrete on a regular basis. 6. Temporary Above-Grade Concrete Washout Facility a) Temporary concrete washout facility (type above grade) should be constructed as shown on the details below, with a recommended minimum length and minimum width of 10 ft, but with sufficient quantity and volume to contain all liquid and concrete waste generated by washout operations. b) Plastic lining material should be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. 7. Temporary Below-Grade Concrete Washout Facility a) Temporary concrete washout facilities (type below grade) should be constructed as shown on the details below, with a recommended minimum length and minimum width of 10 ft. The quantity and volume should be sufficient to contain all liquid and concrete waste generated by washout operations. b) Lath and flagging should be commercial type. c) Plastic lining material shall be a minimum of 10 mil polyethylene sheeting and should be free of holes, tears, or other defects that compromise the impermeability of the material. d) Liner seams shall be installed in accordance with manufacturers’ recommendations. D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-75 e) Soil base shall be prepared free of rocks or other debris that may cause tears or holes in the plastic lining material. Maintenance Standards Inspection and Maintenance 1. Inspect and verify that concrete washout BMPs are in place prior to the commencement of concrete work. 2. During periods of concrete work, inspect daily to verify continued performance. a) Check overall condition and performance. b) Check remaining capacity (% full). c) If using self-installed washout facilities, verify plastic liners are intact and sidewalls are not damaged. d) If using prefabricated containers, check for leaks. 3. Washout facilities shall be maintained to provide adequate holding capacity with a minimum freeboard of 12 inches. 4. Washout facilities must be cleaned, or new facilities must be constructed and ready for use once the washout is 75% full. 5. If the washout is nearing capacity, vacuum and dispose of the waste material in an approved manner. a) Do not discharge liquid or slurry to waterways, storm drains or directly onto ground. b) Do not use sanitary sewer without local approval. c) Place a secure, non-collapsing, non-water collecting cover over the concrete washout facility prior to predicted wet weather to prevent accumulation and overflow of precipitation. d) Remove and dispose of hardened concrete and return the structure to a functional condition. Concrete may be reused onsite or hauled away for disposal or recycling. 6. When you remove materials from the self-installed concrete washout, build a new structure; or, if the previous structure is still intact, inspect for signs of weakening or damage, and make any necessary repairs. Re-line the structure with new plastic after each cleaning. Removal of Temporary Concrete Washout Facilities 1. When temporary concrete washout facilities are no longer required for the work, the hardened concrete, slurries and liquids shall be removed and properly disposed of. 2. Materials used to construct temporary concrete washout facilities shall be removed from the site of the work and disposed of or recycled. 3. Holes, depressions or other ground disturbance caused by the removal of the temporary concrete washout facilities shall be backfilled, repaired, and stabilized to prevent erosion. SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-76 FIGURE D.2.2.2.A CONCRETE WASHOUT AREA (ABOVE GRADE) SECTION B-B NTS SECTION A-A NTS STAPLE DETAIL NTS PLAN NTS ABOVE GRADE TEMPORARY CONCRETE WASHOUT FACILITY NTS CONCRETE WASHOUT SIGN DETAIL NTS 10 mil PLASTIC LINING PLAN NTS TYPE "ABOVE GRADE" WITH WOOD PLANKS TYPE "ABOVE GRADE" WITH STRAW BALES 10 mil PLASTIC LINING 16 GAUGE STEEL WIRE 2" 8" LAG SCREWS ( 12" ) BLACK LETTERS 6" HEIGHT PLYWOOD 4' X 2' PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' STRAW BALES (TYP.) STAKE (TYP.) WEDGE LOOSE STRAW BETWEEN BALES SAND OR GRAVEL-FILLED BAGS IN CORNERS 10' MIN. RECOMMENDED VARIES WOOD OR METAL STAKES (2 PER BALE) STRAW BALES (2 BALES HIGH, MAX.) ORIGINAL GROUND 10 mil PLASTIC LINING STAPLES (2 PER BALE) SAND OR GRAVEL-FILLED BAGS IN CORNERS NATIVE MATERIAL (OPTIONAL) 10 mil PLASTIC LINING WOOD FRAME SECURELY FASTENED AROUND ENTIRE PERIMETER WITH TWO STAKES TWO-STACKED 2x12 ROUGH WOOD FRAME STAKE (TYP.) 10' MIN. RECOMMENDED VARIES NOTES: 1. ACTUAL LAYOUT DETERMINED IN THE FIELD 2. THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30' OF THE FACILITY 1' MIN. Adapted from CalTrans Fig4-14 SAC 8-14-02 D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-77 FIGURE D.2.2.2.B CONCRETE WASHOUT AREA (BELOW GRADE) FIGURE D.2.2.2.C PREFABRICATED CONCRETE WASHOUT CONTAINER W/RAMP EARTHEN BERM TYPICAL SECTION NTS BELOW GRADE TEMPORARY CONCRETE WASHOUT FACILITY NTS CONCRETE WASHOUT SIGN DETAIL NTS SANDBAG PLAN NTS Adapted from CalTrans Fig4-14 SAC 8-14-02 10 mil PLASTIC LINING LAG SCREWS ( 12" ) BLACK LETTERS 6" HEIGHT PLYWOOD 4' X 2' PAINTED WHITE WOOD POST 312" x 312" x 8'3' 3' EARTHEN BERM 10 mil PLASTIC LINING SANDBAG 10' MIN. RECOMMENDED VARIES BERM 3' LATH AND FLAGGING ON 3 SIDES NOTES: 1. ACTUAL LAYOUT DETERMINED IN THE FIELD 2. THE CONCRETE WASHOUT SIGN SHALL BE INSTALLED WITHIN 30' OF THE FACILITY SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-78 D.2.2.3 SAWCUTTING AND SURFACING POLLUTION PREVENTION Purpose Sawcutting and surfacing operations generate slurry and process water that contains fine particles and high pH (concrete cutting), both of which can violate the water quality standards in the receiving water. Concrete spillage or concrete discharge to surface waters of the State is prohibited. Use this BMP to minimize and eliminate process water and slurry created through sawcutting or surfacing from entering waters of the State. Conditions of Use Utilize these management practices anytime sawcutting or surfacing operations take place. Sawcutting and surfacing operations include, but are not limited to, sawing, coring, grinding, roughening, hydro- demolition, bridge and road surfacing Design and Installation Specifications 1. Vacuum slurry and cuttings during cutting and surfacing operations. 2. Slurry and cuttings shall not remain on permanent concrete or asphalt pavement overnight. 3. Slurry and cuttings shall not drain to any natural or constructed drainage conveyance including stormwater systems. This may require temporarily blocking catch basins. 4. Dispose of collected slurry and cuttings in a manner that does not violate ground water or surface water quality standards. 5. Do not allow process water generated during hydro-demolition, surface roughening or similar operations to drain to any natural or constructed drainage conveyance including stormwater systems. Dispose process water in a manner that does not violate ground water or surface water quality standards. 6. Handle and dispose cleaning waste material and demolition debris in a manner that does not cause contamination of water. Dispose of sweeping material from a pick-up sweeper at an appropriate disposal site. Maintenance Standards Continually monitor operations to determine whether slurry, cuttings, or process water could enter waters of the state. If inspections show that a violation of water quality standards could occur, stop operations and immediately implement preventive measures such as berms, barriers, secondary containment, and vacuum trucks. D.2.2.4 MATERIAL DELIVERY, STORAGE, AND CONTAINMENT Purpose Prevent, reduce, or eliminate the discharge of pollutants to the stormwater system or watercourses from material delivery and storage. Minimize the storage of hazardous materials onsite, store materials in a designated area, and install secondary containment. Conditions of Use These procedures are suitable for use at all construction sites with delivery and storage of the following materials: Petroleum products such as fuel, oil and grease Soil stabilizers and binders (e.g., Polyacrylamide) Fertilizers, pesticides and herbicides Detergents Asphalt and concrete compounds D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-79 Hazardous chemicals such as acids, lime, adhesives, paints, solvents and curing compounds Any other material that may be detrimental if released to the environment Design and Installation Specifications The following steps should be taken to minimize risk: 1. Temporary storage area should be located away from vehicular traffic, near the construction entrance(s), and away from waterways or storm drains. 2. Material Safety Data Sheets (MSDS) should be supplied for all materials stored. Chemicals should be kept in their original labeled containers. 3. Hazardous material storage onsite should be minimized. 4. Hazardous materials should be handled as infrequently as possible. 5. During the wet weather season (October 1 – April 30), consider storing materials in a covered area. 6. Materials should be stored in secondary containments, such as earthen dike, horse trough, or even a children’s wading pool for non-reactive materials such as detergents, oil, grease, and paints. Small amounts of material may be secondarily contained in “bus boy” trays or concrete mixing trays. 7. Do not store chemicals, drums, or bagged materials directly on the ground. Place these items on a pallet and, when possible, and within secondary containment. 8. If drums must be kept uncovered, store them at a slight angle to reduce ponding of rainwater on the lids to reduce corrosion. Domed plastic covers are inexpensive and snap to the top of drums, preventing water from collecting. Material Storage Areas and Secondary Containment Practices: 1. Liquids, petroleum products, and substances listed in 40 CFR Parts 110, 117, or 302 shall be stored in approved containers and drums and shall not be overfilled. Containers and drums shall be stored in temporary secondary containment facilities. 2. Temporary secondary containment facilities shall provide for a spill containment volume able to contain 10% of the total enclosed container volume of all containers, or 110% of the capacity of the largest container within its boundary, whichever is greater. 3. Secondary containment facilities shall be impervious to the materials stored therein for a minimum contact time of 72 hours. 4. Secondary containment facilities shall be maintained free of accumulated rainwater and spills. In the event of spills or leaks, accumulated rainwater and spills shall be collected and placed into drums. These liquids shall be handled as hazardous waste unless testing determines them to be non- hazardous. 5. Sufficient separation should be provided between stored containers to allow for spill cleanup and emergency response access. 6. During the wet weather season (October 1 – April 30), each secondary containment facility shall be covered during non-working days, prior to and during rain events. 7. Keep material storage areas clean, organized and equipped with an ample supply of appropriate spill clean-up material (spill kit). 8. The spill kit should include, at a minimum: 1-Water Resistant Nylon Bag 3-Oil Absorbent Socks 3″ x 4′ 2-Oil Absorbent Socks 3″ x 10′ 12-Oil Absorbent Pads 17″ x 19″ SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-80 1-Pair Splash Resistant Goggles 3-Pair Nitrile Gloves 10-Disposable Bags with Ties Instructions SECTION D.2 GENERAL CSWPP REQUIREMENTS 6/22/2022 2022 City of Renton Surface Water Design Manual D-100 proper disposal must be submitted to the City. All authorizations for disposal shall be obtained prior to CKD/CTB application. Infiltration: Depending on the site conditions, pH-adjusted stormwater may be infiltrated. Prior to infiltration, pH must be between 6.5 and 8.5. Surface Water: Contact water from the application area shall not be discharged to surface waters, even if treatment has adjusted the pH. 8. Emergency backup plan: An emergency backup plan must be prepared and ready to implement to handle large quantities of stormwater. 9. Monitoring shall be conducted to determine that contact stormwater is not leaving the site. Offsite monitoring shall also be conducted to identify impacts to adjacent water bodies. Bonding may be required to cover mitigation of impacts and restoration. 10. A soils specialist will establish the mixing percentage for onsite soils. Soil amendments will never occur in excess of the ability of the onsite equipment and resources to meet all BMP requirements. 11. For sites one acre or larger, a Construction Stormwater General permit must be obtained from Ecology. Construction Stormwater General permits and ‘Stormwater Pollution Prevention Plans (SWPPPs) must be amended and the use of CKD/CTB must be approved by Ecology prior to application. The contractor/developer shall comply will all federal, state, and local regulations. A health and safety plan may be required for the protection of CED inspectors. Additional BMPs may be applicable depending on mix design, proximity of wetlands or streams (e.g., within 300 feet of class/type I and 100 feet or less for other types) and site conditions. D.2.2.10 MAINTAIN PROTECTIVE BMPS Pollutant protection measures shall be maintained to ensure continued performance of their intended function. Reporting and documentation shall be kept current and made available to CED as indicated. Purpose: The purpose of maintaining protective BMPs is to provide effective pollutant protection when and where required by the plan and the project, and to provide timely and relevant project information. When to Maintain: Protection measures shall be monitored per Section D.2.4.4 at a minimum, continuously during operation, and promptly maintained to fully functioning condition as necessary to ensure continued performance of their intended function. Documentation shall be kept current per specific BMP requirements. Measures to Use: 1. Maintain and repair all pollutant control BMPs as needed to ensure continued performance of their intended function in accordance with BMP specifications. 2. Maintain and repair storage locations for equipment and materials associated with BMP processes. Conduct materials disposal in compliance with City requirements. 3. As required, provide current reporting and performance documentation at an accessible location for the site inspector and other CED staff. 4. Remove all temporary pollutant control BMPs prior to final construction approval, or within 30 days after achieving final site stabilization or after the temporary BMPs are no longer needed. D.2.2.11 MANAGE THE PROJECT SWPPP requirements shall be implemented and managed as part of the overall CSWPP plan. Concrete construction and its impacts are primary among pollutant concerns on site development projects. Fueling operations and materials containment of treatment chemicals and other project materials are also typical D.2.2 SWPPS MEASURES 2022 City of Renton Surface Water Design Manual 6/22/2022 D-101 pollutant concerns. Operations that produce these and other pollutants are often conducted by subcontractors and their laborers, yet may require specific protective measures, documentation and reporting. Protective measures and BMPs need to be made available prior to construction and suitable oversight provided to ensure inspection, monitoring and documentation requirements are met. Projects shall assign a qualified CSWPP Supervisor (Section D.2.3.1) to be the primary contact for SWPPP and ESC issues and reporting, coordination with subcontractors and implementation of the CSWPP plan as a whole. Measures to Use: 1. Phase development projects to the maximum degree practicable and take into account seasonal work limits. 2. Inspection and monitoring – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Conduct site inspections and monitoring in accordance with the Construction Stormwater General Permit and City requirements. Coordinate with subcontractors and laborers to ensure the SWPPP measures are followed. 3. Documentation and reporting – Inspect, maintain, and repair all BMPs as needed to ensure continued performance of their intended function. Document site inspections and monitoring in accordance with the Construction Stormwater General Permit, specific BMP conditions and City requirements. Log sheets provided in Reference Section 8 may be used if appropriate. Follow reporting requirements and provide documentation as requested to CED staff. 4. Maintaining an updated construction SWPPP – Maintain, update, and implement the SWPPP in accordance with the Construction Stormwater General Permit and City requirements. Obtain approval for specific SWPPP measures (e.g., chemical treatments of stormwater) well in advance of need. Coordinate SWPPP plan updates with the site inspector (see Section D.2.4.1). D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2022 City of Renton Surface Water Design Manual 6/22/2022 D-133 Pollution Prevention Team Completed by: ______________________ Title: ______________________________ Date: ______________________________ Responsible Official: Title: ___________________________ Team Leader: Office Phone:____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ (1) Title:____________________________ Office Phone: ____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ (2) Title:____________________________ Office Phone: ____________________ Cell Phone #: ____________________ Responsibilities: _______________________________ _______________________________ _______________________________ D.4 REFERENCE SECTION 6/22/2022 2022 City of Renton Surface Water Design Manual D-134 Employee Training Completed by:______________________________________ Title:______________________________________________ Date: ______________________________________________ Describe the annual training of employees on the SWPPP, addressing spill response, good housekeeping, and material management practices. Training Topics 1.) LINE WORKERS Brief Description of Training Program/Materials (e.g., film, newsletter course) Schedule for Training (list dates) Attendees Spill Prevention and Response Good Housekeeping Material Management Practices 2.) P2 TEAM: SWPPP Implementation Monitoring Procedures D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2022 City of Renton Surface Water Design Manual 6/22/2022 D-135 List of Significant Spills and Leaks Completed by: Title: Date: List all spills and leaks of toxic or hazardous pollutants that were significant but are not limited to, release of oil or hazardous substances in excess of reportable quantities. Although not required, we suggest you list spills and leaks of non-hazardous materials. Description Response Procedure Date (month/day/ year) Location (as indicated on site map) Type of Material Quantity Source, If Known Reason for Spill/Leak Amount of Material Recovered Material No longer exposed to Stormwater (Yes/No) Preventive Measure Taken D.4 REFERENCE SECTION 6/22/2022 2022 City of Renton Surface Water Design Manual D-136 Potential Pollutant Source Identification Completed by: Title: Date: List all potential stormwater pollutants from materials handled, treated, or stored onsite. Potential Stormwater Pollutant Stormwater Pollutant Source Likelihood of pollutant being present in your stormwater discharge. If yes, explain D.4.3 ESC AND SWPPS MAINTENANCE REPORTS 2022 City of Renton Surface Water Design Manual 6/22/2022 D-137 Material Inventory Completed by: Title: Date: List materials handled, treated, stored, or disposed of at the project site that may potentially be exposed to precipitation or runoff. Material Purpose/Location Quantity (Units) Likelihood of contact with stormwater Past Spill or Used Produced Stored If Yes, describe reason Leak (indicate per week or year) Yes No Technical Information Report New Renton High School Project No. 2230388.10 Appendix G Bonds and Covenants G-1 ................... Bond Quantity Worksheet Phase 1 G-2 ................... Bond Quantity Worksheet Phase 2 1055 South Grady Way – 6 th Floor | Renton, WA 98057 (425) 430-7200 • • Section I: Project Information • • • Section II: Bond Quantities Worksheets • •Section II.a EROSION CONTROL (Stabilization/Erosion Sediment Control (ESC)) •Section II.b TRANSPORTATION (Street and Site Improvements) •Section II.c DRAINAGE (Drainage and Stormwater Facilities): •Section II.d WATER - ONLY APPLICABLE IF WATER SERVICE IS PROVIDED BY CITY OF RENTON •Section II.e SANITARY SEWER - ONLY APPLICABLE IF SEWER SERVICE IS PROVIDED BY CITY OF RENTON • • • • • • Section III. Bond Worksheet • BOND QUANTITY WORKSHEET INSTRUCTIONS This worksheet is intended to be a "working" copy of the bond quantity worksheet, which will be used throughout all phases of the project, from initial submittal to project close-out approval. Submit this workbook, in its entirety, as follows: The following forms are to be completed by the engineer/developer/applicant as applicable to the project: The Bond Worksheet form will auto-calculate and auto-populate from the information provided in Section I and Section II. This section includes all pertinent information for the project Section II contains a separate spreadsheet TAB for each of the following specialties: (1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for civil construction permit submittal. Hard copies are to be included as part of the Technical Information Report (TIR). (1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for final close-out submittal. This section must be completed in its entirety Information from this section auto-populates to all other relevant areas of the workbook This section calculates the required Permit Bond for construction permit issuance as well as the required Maintenance Bond for project close-out submittals to release the permit bond on a project. All unit prices include labor, equipment, materials, overhead, profit, and taxes. Complete the 'Quantity' columns for each of the appropriate section(s). Include existing Right-of-Way (ROW), Future Public Improvements and Private Improvements. The 'Quantity Remaining' column is only to be used when a project is under construction. The City allows one (1) bond reduction during the life of the project with the exception of the maintenance period reduction. Excel will auto-calculate and auto-populate the relevant fields and subtotals throughout the document. Only the 'Quantity' columns should need completing. Additional items not included in the lists can be added under the "write-in" sections. Provide a complete description, cost estimate and unit of measure for each write-in item. Note: Private improvements, with the exception of stormwater facilities, are not included in the bond amount calculation, but must be entered on the form. Stormwater facilities (public and private) are required to be included in the bond amount. Page 1 of 16 Ref 8-H Bond Quantity Worksheet INSTRUCTIONS Version: 1/2/2026 Printed 6/11/2026 1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200 Date Prepared: Name: PE Registration No: Firm Name: Firm Address: Phone No. Email Address: Project Name: Project Owner: CED Plan # (LUA): Phone: CED Permit # (C):Address: Site Address: Street Intersection: Addt'l Project Owner: Parcel #(s): Phone: Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NO Water Service Provided by: If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: Total Estimated Construction Costs E A + B + C + D 3,251,659.19$ Estimated Civil Construction Permit - Construction Costs2 Stormwater (Drainage)C 642,422.69$ As outlined in City Ordinance No. 4345, 50% of the plan review and inspection fees are to be paid at Permit Submittal. The balance is due at Permit Issuance. Significant changes or additional review cycles (beyond 3 cycles) during the review process may result in adjustments to the final review fees. Roadway (Erosion Control + Transportation)D 2,371,094.64$ Water A 208,804.12$ Wastewater (Sanitary Sewer)B 29,337.75$ Abbreviated Legal Description: A PORTION OF H. H. TOBIN DONATION LAND CLAIM NO. 37 IN THE NORTHEAST QUARTER OF SECTION 18, TOWNSHIP 23 NORTH, RANGE 5 EAST, WILLAMETTE MERIDIAN, IN KING COUNTY, WASHINGTON 400 S 2nd St, Renton, WA 98057 7812 S 124th St S 2nd St and Logan Ave S C26000333 LUA25-000343 425-404-4423 6/10/2026 Prepared by: FOR APPROVALProject Phase 1 wfierst@ahbl.com William J. Fierst 41803 AHBL 2215 N 20th St, Tacoma, WA 98403 253-383-2422 SITE IMPROVEMENT BOND QUANTITY WORKSHEET PROJECT INFORMATION CITY OF RENTON CITY OF RENTON 1 Select the current project status/phase from the following options: For Approval - Preliminary Data Enclosed, pending approval from the City; For Construction - Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout - Final Costs and Quantities Enclosed for Project Close-out Submittal Engineer Stamp Required (all cost estimates must have original wet stamp and signature) Clearing and Grading Utility Providers N/A Project Location and Description Project Owner Information Renton High School Phase 1 Seattle, WA 98178 000720-0060 & 42 other parcels Renton School District #403 Page 2 of 16 Ref 8-H Bond Quantity Worksheet SECTION I PROJECT INFORMATION Version 1/2/2026 Printed 6/11/2026 06/11/2026 CED Permit #:C26000333 Unit Reference #Price Unit Quantity Cost Backfill & compaction-embankment ESC-1 7.50$ CY Check dams, 4" minus rock ESC-2 SWDM 5.4.6.3 90.00$ Each 6 540.00 Catch Basin Protection ESC-3 145.00$ Each 18 2,610.00 Crushed surfacing 1 1/4" minus ESC-4 WSDOT 9-03.9(3)110.00$ CY 1650 181,500.00 Ditching ESC-5 10.50$ CY Excavation-bulk ESC-6 2.30$ CY 2530 5,819.00 Fence, silt ESC-7 SWDM 5.4.3.1 5.00$ LF 500 2,500.00 Fence, Temporary (NGPE)ESC-8 1.75$ LF Geotextile Fabric ESC-9 3.00$ SY Hay Bale Silt Trap ESC-10 0.60$ Each Hydroseeding ESC-11 SWDM 5.4.2.4 0.90$ SY 27000 24,300.00 Interceptor Swale / Dike ESC-12 1.15$ LF 800 920.00 Jute Mesh ESC-13 SWDM 5.4.2.2 4.00$ SY Level Spreader ESC-14 2.00$ LF Mulch, by hand, straw, 3" deep ESC-15 SWDM 5.4.2.1 2.90$ SY Mulch, by machine, straw, 2" deep ESC-16 SWDM 5.4.2.1 2.30$ SY Piping, temporary, CPP, 6"ESC-17 13.75$ LF Piping, temporary, CPP, 8"ESC-18 16.00$ LF Piping, temporary, CPP, 12"ESC-19 20.50$ LF 100 2,050.00 Plastic covering, 6mm thick, sandbagged ESC-20 SWDM 5.4.2.3 4.60$ SY 2400 11,040.00 Rip Rap, machine placed; slopes ESC-21 WSDOT 9-13.1(2)51.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22 SWDM 5.4.4.1 2,050.00$ Each Rock Construction Entrance, 100'x15'x1'ESC-23 SWDM 5.4.4.1 3,675.00$ Each 2 7,350.00 Sediment pond riser assembly ESC-24 SWDM 5.4.5.2 2,525.00$ Each Sediment trap, 5' high berm ESC-25 SWDM 5.4.5.1 22.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC-26 SWDM 5.4.5.1 80.00$ LF Seeding, by hand ESC-27 SWDM 5.4.2.4 1.15$ SY Sodding, 1" deep, level ground ESC-28 SWDM 5.4.2.5 9.20$ SY Sodding, 1" deep, sloped ground ESC-29 SWDM 5.4.2.5 11.50$ SY TESC Supervisor ESC-30 125.00$ HR 130 16,250.00 Water truck, dust control ESC-31 SWDM 5.4.7 160.00$ HR Unit Reference #Price Unit Quantity Cost EROSION/SEDIMENT SUBTOTAL:254,879.00 SALES TAX @ 10.5%26,762.30 EROSION/SEDIMENT TOTAL:281,641.30 (A) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR EROSION & SEDIMENT CONTROL Description No. (A) WRITE-IN-ITEMS Page 4 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.a EROSION_CONTROL Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost GENERAL ITEMS Backfill & Compaction- embankment GI-1 7.00$ CY Backfill & Compaction- trench GI-2 10.25$ CY 150 1,537.50 4000 41,000.00 Clear/Remove Brush, by hand (SY)GI-3 1.15$ SY Bollards - fixed GI-4 275.00$ Each Bollards - removable GI-5 520.00$ Each Clearing/Grubbing/Tree Removal GI-6 11,475.00$ Acre 0.3 3,442.50 5.2 59,670.00 Excavation - bulk GI-7 2.30$ CY 900 2,070.00 Excavation - Trench GI-8 5.75$ CY Fencing, cedar, 6' high GI-9 23.00$ LF Fencing, chain link, 4'GI-10 44.00$ LF Fencing, chain link, vinyl coated, 6' high GI-11 23.00$ LF Fencing, chain link, gate, vinyl coated, 20' GI-12 1,600.00$ Each Fill & compact - common barrow GI-13 28.75$ CY 270 7,762.50 13000 373,750.00 Fill & compact - gravel base GI-14 31.00$ CY 220 6,820.00 3130 97,030.00 Fill & compact - screened topsoil GI-15 44.75$ CY 3900 174,525.00 Gabion, 12" deep, stone filled mesh GI-16 74.50$ SY Gabion, 18" deep, stone filled mesh GI-17 103.25$ SY Gabion, 36" deep, stone filled mesh GI-18 172.00$ SY Grading, fine, by hand GI-19 2.90$ SY Grading, fine, with grader GI-20 2.30$ SY 1500 3,450.00 8400 19,320.00 Monuments, 3' Long GI-21 1,025.00$ Each Sensitive Areas Sign GI-22 8.00$ Each Sodding, 1" deep, sloped ground GI-23 9.25$ SY Surveying, line & grade GI-24 975.00$ Day Surveying, lot location/lines GI-25 2,050.00$ Acre Topsoil Type A (imported)GI-26 32.75$ CY Traffic control crew ( 2 flaggers )GI-27 137.75$ HR 160 22,040.00 Trail, 4" chipped wood GI-28 9.15$ SY Trail, 4" crushed cinder GI-29 10.25$ SY Trail, 4" top course GI-30 13.75$ SY Conduit, 2"GI-31 5.75$ LF Wall, retaining, concrete GI-32 63.00$ SF Wall, rockery GI-33 17.25$ SF SUBTOTAL THIS PAGE:45,052.50 767,365.00 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) Page 5 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) ROAD IMPROVEMENT/PAVEMENT/SURFACING AC Grinding, 4' wide machine < 1000sy RI-1 34.50$ SY AC Grinding, 4' wide machine 1000-2000sy RI-2 18.25$ SY AC Grinding, 4' wide machine > 2000sy RI-3 11.50$ SY AC Removal/Disposal RI-4 40.00$ SY 576 23,040.00 5560 222,400.00 Barricade, Type III ( Permanent )RI-5 64.25$ LF Guard Rail RI-6 34.50$ LF Curb & Gutter, rolled RI-7 19.50$ LF Curb & Gutter, vertical RI-8 14.25$ LF 490 6,982.50 40 570.00 Curb and Gutter, demolition and disposal RI-9 20.50$ LF 490 10,045.00 40 820.00 Curb, extruded asphalt RI-10 6.25$ LF Curb, extruded concrete RI-11 8.00$ LF Sawcut, asphalt, 3" depth RI-12 3.00$ LF 805 2,415.00 256 768.00 Sawcut, concrete, per 1" depth RI-13 5.00$ LF 90 450.00 Sealant, asphalt RI-14 2.25$ LF Shoulder, gravel, 4" thick RI-15 17.25$ SY Sidewalk, 4" thick RI-16 43.50$ SY 1060 46,110.00 1605 69,817.50 Sidewalk, 4" thick, demolition and disposal RI-17 37.00$ SY 330 12,210.00 1950 72,150.00 Sidewalk, 5" thick RI-18 47.00$ SY 235 11,045.00 Sidewalk, 5" thick, demolition and disposal RI-19 46.00$ SY Sign, Handicap RI-20 97.00$ Each Striping, per stall RI-21 8.00$ Each Striping, thermoplastic, ( for crosswalk )RI-22 3.50$ SF Striping, 4" reflectorized line RI-23 0.55$ LF Additional 2.5" Crushed Surfacing RI-24 4.15$ SY HMA 1/2" Overlay 1.5" RI-25 16.00$ SY HMA 1/2" Overlay 2"RI-26 20.75$ SY HMA Road, 2", 4" rock, First 2500 SY RI-27 32.25$ SY 2500 80,625.00 HMA Road, 2", 4" rock, Qty. over 2500SY RI-28 24.00$ SY 5813 139,512.00 HMA Road, 4", 6" rock, First 2500 SY RI-29 51.75$ SY 382 19,768.50 2500 129,375.00 HMA Road, 4", 6" rock, Qty. over 2500 SY RI-30 42.50$ SY 4389 186,532.50 HMA Road, 4", 4.5" ATB RI-31 43.50$ SY Gravel Road, 4" rock, First 2500 SY RI-32 17.25$ SY Gravel Road, 4" rock, Qty. over 2500 SY RI-33 11.50$ SY Thickened Edge RI-34 10.00$ LF SUBTOTAL THIS PAGE:132,066.00 902,570.00 (B)(C)(D)(E) Page 6 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) PARKING LOT SURFACING No. 2" AC, 2" top course rock & 4" borrow PL-1 24.00$ SY 2" AC, 1.5" top course & 2.5" base course PL-2 32.00$ SY 4" select borrow PL-3 5.75$ SY 1.5" top course rock & 2.5" base course PL-4 16.00$ SY SUBTOTAL PARKING LOT SURFACING: (B)(C)(D)(E) LANDSCAPING & VEGETATION No. Street Trees LA-1 825.00$ EA 42 34,650.00 Median Landscaping LA-2 0.50$ SF 14209 7,104.50 Right-of-Way Landscaping LA-3 Wetland Landscaping LA-4 SUBTOTAL LANDSCAPING & VEGETATION:7,104.50 34,650.00 (B)(C)(D)(E) TRAFFIC & LIGHTING No. Signs TR-1 300.00$ EA 7 2,100.00 Street Light System ( # of Poles)TR-2 Traffic Signal TR-3 Traffic Signal Modification TR-4 SUBTOTAL TRAFFIC & LIGHTING:2,100.00 (B)(C)(D)(E) WRITE-IN-ITEMS SUBTOTAL WRITE-IN ITEMS: STREET AND SITE IMPROVEMENTS SUBTOTAL:184,223.00 1,706,685.00 SALES TAX @ 10.5%19,343.42 179,201.93 STREET AND SITE IMPROVEMENTS TOTAL:203,566.42 1,885,886.93 (B)(C)(D)(E) Page 7 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost DRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D-1 30.00$ SY * (CBs include frame and lid) Beehive D-2 103.00$ Each Through-curb Inlet Framework D-3 460.00$ Each CB Type I D-4 1,725.00$ Each 41 70,725.00 CB Type IL D-5 2,000.00$ Each 2 4,000.00 CB Type II, 48" diameter D-6 3,500.00$ Each 9 31,500.00 for additional depth over 4' D-7 550.00$ FT CB Type II, 54" diameter D-8 4,075.00$ Each for additional depth over 4'D-9 570.00$ FT CB Type II, 60" diameter D-10 4,225.00$ Each 2 8,450.00 for additional depth over 4'D-11 690.00$ FT CB Type II, 72" diameter D-12 6,900.00$ Each for additional depth over 4'D-13 975.00$ FT CB Type II, 96" diameter D-14 16,000.00$ Each for additional depth over 4'D-15 1,050.00$ FT Trash Rack, 12"D-16 400.00$ Each Trash Rack, 15"D-17 470.00$ Each Trash Rack, 18"D-18 550.00$ Each Trash Rack, 21"D-19 630.00$ Each Cleanout, PVC, 4"D-20 170.00$ Each Cleanout, PVC, 6"D-21 195.00$ Each Cleanout, PVC, 8"D-22 230.00$ Each 1 230.00 Culvert, PVC, 4" D-23 11.50$ LF Culvert, PVC, 6" D-24 15.00$ LF 23 345.00 Culvert, PVC, 8" D-25 17.00$ LF Culvert, PVC, 12" D-26 26.00$ LF Culvert, PVC, 15" D-27 40.00$ LF Culvert, PVC, 18" D-28 47.00$ LF Culvert, PVC, 24"D-29 65.00$ LF Culvert, PVC, 30" D-30 90.00$ LF Culvert, PVC, 36" D-31 150.00$ LF Culvert, CMP, 8"D-32 22.00$ LF Culvert, CMP, 12"D-33 33.00$ LF SUBTOTAL THIS PAGE:115,250.00 (B)(C)(D)(E) Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Page 8 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES DRAINAGE (Continued) Culvert, CMP, 15"D-34 40.00$ LF Culvert, CMP, 18"D-35 47.00$ LF Culvert, CMP, 24"D-36 64.00$ LF 26 1,664.00 Culvert, CMP, 30"D-37 90.00$ LF Culvert, CMP, 36"D-38 150.00$ LF Culvert, CMP, 48"D-39 218.00$ LF Culvert, CMP, 60"D-40 310.00$ LF 672 208,320.00 Culvert, CMP, 72"D-41 400.00$ LF Culvert, Concrete, 8"D-42 48.00$ LF Culvert, Concrete, 12"D-43 55.00$ LF Culvert, Concrete, 15"D-44 89.00$ LF Culvert, Concrete, 18"D-45 100.00$ LF Culvert, Concrete, 24"D-46 120.00$ LF Culvert, Concrete, 30"D-47 145.00$ LF Culvert, Concrete, 36"D-48 175.00$ LF Culvert, Concrete, 42"D-49 200.00$ LF Culvert, Concrete, 48"D-50 235.00$ LF Culvert, CPE Triple Wall, 6" D-51 16.00$ LF Culvert, CPE Triple Wall, 8" D-52 18.00$ LF 32 576.00 Culvert, CPE Triple Wall, 12" D-53 27.00$ LF 1990 53,730.00 Culvert, CPE Triple Wall, 15" D-54 40.00$ LF Culvert, CPE Triple Wall, 18" D-55 47.00$ LF Culvert, CPE Triple Wall, 24" D-56 64.00$ LF Culvert, CPE Triple Wall, 30" D-57 90.00$ LF Culvert, CPE Triple Wall, 36" D-58 149.00$ LF Culvert, LCPE, 6"D-59 69.00$ LF Culvert, LCPE, 8"D-60 83.00$ LF Culvert, LCPE, 12"D-61 96.00$ LF Culvert, LCPE, 15"D-62 110.00$ LF Culvert, LCPE, 18"D-63 124.00$ LF Culvert, LCPE, 24"D-64 138.00$ LF Culvert, LCPE, 30"D-65 151.00$ LF Culvert, LCPE, 36"D-66 165.00$ LF Culvert, LCPE, 48"D-67 179.00$ LF Culvert, LCPE, 54"D-68 193.00$ LF SUBTOTAL THIS PAGE:576.00 263,714.00 (B)(C)(D)(E) Page 9 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES DRAINAGE (Continued) Culvert, LCPE, 60"D-69 206.00$ LF Culvert, LCPE, 72"D-70 220.00$ LF Culvert, HDPE, 6"D-71 48.00$ LF Culvert, HDPE, 8"D-72 60.00$ LF Culvert, HDPE, 12"D-73 85.00$ LF Culvert, HDPE, 15"D-74 122.00$ LF Culvert, HDPE, 18"D-75 158.00$ LF Culvert, HDPE, 24"D-76 254.00$ LF Culvert, HDPE, 30"D-77 317.00$ LF Culvert, HDPE, 36"D-78 380.00$ LF Culvert, HDPE, 48"D-79 443.00$ LF Culvert, HDPE, 54"D-80 506.00$ LF Culvert, HDPE, 60"D-81 570.00$ LF Culvert, HDPE, 72"D-82 632.00$ LF Pipe, Polypropylene, 6"D-83 96.00$ LF Pipe, Polypropylene, 8"D-84 100.00$ LF Pipe, Polypropylene, 12"D-85 100.00$ LF Pipe, Polypropylene, 15"D-86 103.00$ LF Pipe, Polypropylene, 18"D-87 106.00$ LF Pipe, Polypropylene, 24"D-88 119.00$ LF Pipe, Polypropylene, 30"D-89 136.00$ LF Pipe, Polypropylene, 36"D-90 185.00$ LF Pipe, Polypropylene, 48"D-91 260.00$ LF Pipe, Polypropylene, 54"D-92 381.00$ LF Pipe, Polypropylene, 60"D-93 504.00$ LF Pipe, Polypropylene, 72"D-94 625.00$ LF Culvert, DI, 6"D-95 70.00$ LF 68 4,760.00 Culvert, DI, 8"D-96 101.00$ LF Culvert, DI, 12"D-97 121.00$ LF 918 111,078.00 Culvert, DI, 15"D-98 148.00$ LF Culvert, DI, 18"D-99 175.00$ LF Culvert, DI, 24"D-100 200.00$ LF Culvert, DI, 30"D-101 227.00$ LF Culvert, DI, 36"D-102 252.00$ LF Culvert, DI, 48"D-103 279.00$ LF Culvert, DI, 54"D-104 305.00$ LF Culvert, DI, 60"D-105 331.00$ LF Culvert, DI, 72"D-106 357.00$ LF SUBTOTAL THIS PAGE:115,838.00 (B)(C)(D)(E) Page 10 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Specialty Drainage Items Ditching SD-1 10.90$ CY Flow Dispersal Trench (1,436 base+)SD-3 32.00$ LF French Drain (3' depth)SD-4 30.00$ LF 85 2,550.00 Geotextile, laid in trench, polypropylene SD-5 3.40$ SY Mid-tank Access Riser, 48" dia, 6' deep SD-6 2,300.00$ Each 9 20,700.00 Pond Overflow Spillway SD-7 18.25$ SY Restrictor/Oil Separator, 12"SD-8 1,320.00$ Each Restrictor/Oil Separator, 15"SD-9 1,550.00$ Each Restrictor/Oil Separator, 18"SD-10 1,950.00$ Each Riprap, placed SD-11 48.20$ CY Tank End Reducer (36" diameter)SD-12 1,375.00$ Each 2 2,750.00 Infiltration pond testing SD-13 143.00$ HR Permeable Pavement SD-14 Permeable Concrete Sidewalk SD-15 Culvert, Box __ ft x __ ft SD-16 SUBTOTAL SPECIALTY DRAINAGE ITEMS:26,000.00 (B)(C)(D)(E) STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch) Detention Pond SF-1 Each Detention Tank SF-2 Each Detention Vault SF-3 Each Infiltration Pond SF-4 Each Infiltration Tank SF-5 Each Infiltration Vault SF-6 Each Infiltration Trenches SF-7 Each Basic Biofiltration Swale SF-8 Each Wet Biofiltration Swale SF-9 Each Wetpond SF-10 Each Wetvault SF-11 Each Sand Filter SF-12 Each Sand Filter Vault SF-13 Each Linear Sand Filter SF-14 Each Proprietary Facility SF-15 20,000.00$ Each 3 60,000.00 Bioretention Facility SF-16 Each SUBTOTAL STORMWATER FACILITIES:60,000.00 (B)(C)(D)(E) Page 11 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES WRITE-IN-ITEMS (INCLUDE ON-SITE BMPs) WI-1 WI-2 WI-3 WI-4 WI-5 WI-6 WI-7 WI-8 WI-9 WI-10 WI-11 WI-12 WI-13 WI-14 WI-15 SUBTOTAL WRITE-IN ITEMS: DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:576.00 580,802.00 SALES TAX @ 10.5%60.48 60,984.21 DRAINAGE AND STORMWATER FACILITIES TOTAL:636.48 641,786.21 (B) (C) (D) (E) Page 12 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Connection to Existing Watermain W-1 3,400.00$ Each Ductile Iron Watermain, CL 52, 4 Inch Diameter W-2 58.00$ LF 86 4,988.00 Ductile Iron Watermain, CL 52, 6 Inch Diameter W-3 65.00$ LF 146 9,490.00 Ductile Iron Watermain, CL 52, 8 Inch Diameter W-4 75.00$ LF Ductile Iron Watermain, CL 52, 10 Inch Diameter W-5 80.00$ LF Ductile Iron Watermain, CL 52, 12 Inch Diameter W-6 145.00$ LF 668 96,860.00 Gate Valve, 4 inch Diameter W-7 1,225.00$ Each 1 1,225.00 Gate Valve, 6 inch Diameter W-8 1,350.00$ Each 4 5,400.00 Gate Valve, 8 Inch Diameter W-9 1,550.00$ Each Gate Valve, 10 Inch Diameter W-10 2,100.00$ Each Gate Valve, 12 Inch Diameter W-11 2,500.00$ Each 7 17,500.00 Fire Hydrant Assembly W-12 5,000.00$ Each 4 20,000.00 Permanent Blow-Off Assembly W-13 1,950.00$ Each Air-Vac Assembly, 2-Inch Diameter W-14 3,050.00$ Each Air-Vac Assembly, 1-Inch Diameter W-15 1,725.00$ Each Compound Meter Assembly 3-inch Diameter W-16 9,200.00$ Each Compound Meter Assembly 4-inch Diameter W-17 10,500.00$ Each 1 10,500.00 Compound Meter Assembly 6-inch Diameter W-18 11,500.00$ Each Pressure Reducing Valve Station 8-inch to 10-inch W-19 23,000.00$ Each 1 23,000.00 WATER SUBTOTAL:188,963.00 SALES TAX @ 10.5%19,841.12 WATER TOTAL:208,804.12 (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR WATER Quantity Remaining (Bond Reduction) (B)(C) Page 13 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.d WATER Version 1/2/2026 Printed 6/11/2026 CED Permit #:C26000333 Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Clean Outs SS-1 1,150.00$ Each 2 2,300.00 Grease Interceptor, 500 gallon SS-2 9,200.00$ Each Grease Interceptor, 1000 gallon SS-3 11,500.00$ Each Grease Interceptor, 1500 gallon SS-4 17,200.00$ Each Side Sewer Pipe, PVC. 4 Inch Diameter SS-5 92.00$ LF Side Sewer Pipe, PVC. 6 Inch Diameter SS-6 110.00$ LF 107 11,770.00 Sewer Pipe, PVC, 8 inch Diameter SS-7 120.00$ LF 104 12,480.00 Sewer Pipe, PVC, 12 Inch Diameter SS-8 144.00$ LF Sewer Pipe, DI, 8 inch Diameter SS-9 130.00$ LF Sewer Pipe, DI, 12 Inch Diameter SS-10 150.00$ LF Manhole, 48 Inch Diameter SS-11 6,900.00$ Each Manhole, 54 Inch Diameter SS-13 6,800.00$ Each Manhole, 60 Inch Diameter SS-15 7,600.00$ Each Manhole, 72 Inch Diameter SS-17 10,600.00$ Each Manhole, 96 Inch Diameter SS-19 16,000.00$ Each Pipe, C-900, 12 Inch Diameter SS-21 205.00$ LF Outside Drop SS-24 1,700.00$ LS Inside Drop SS-25 1,150.00$ LS Sewer Pipe, PVC, ____ Inch Diameter SS-26 Lift Station (Entire System)SS-27 LS SANITARY SEWER SUBTOTAL:26,550.00 SALES TAX @ 10.5%2,787.75 SANITARY SEWER TOTAL:29,337.75 (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR SANITARY SEWER Quantity Remaining (Bond Reduction) (B)(C) Page 14 of 16 Ref 8-H Bond Quantity Worksheet SECTION II.e SANITARY SEWER Version 1/2/2026 Printed 6/11/2026 1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200 Date: Name: Project Name: PE Registration No: CED Plan # (LUA): Firm Name:CED Permit # (C): Firm Address: Site Address: Phone No. Parcel #(s): Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a) Existing Right-of-Way Improvements Subtotal (b) (b)203,566.42$ Future Public Improvements Subtotal (c)-$ Stormwater & Drainage Facilities (Public & Private) Subtotal (d) (d)642,422.69$ (e) (f) Site Restoration Existing Right-of-Way and Storm Drainage Improvements Maintenance Bond 169,197.82$ Bond Reduction2 Construction Permit Bond Amount 3 Minimum Bond Amount is $10,000.00 1 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering. 2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% will cover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering. * Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton. EST1 ((b) + (c) + (d)) x 20% -$ MAINTENANCE BOND */** (after final acceptance of construction) 281,641.30$ 203,566.42$ 947,772.31$ 281,641.30$ -$ 642,422.69$ -$ 1,229,413.61$ P (a) x 100% SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS 6/10/2026 William J. Fierst 41803 AHBL R ((b x 150%) + (d x 100%)) S (e) x 150% + (f) x 100% Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2 Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2 T (P +R - S) Prepared by: Project Information CONSTRUCTION BOND AMOUNT */** (prior to permit issuance) 253-383-2422 wfierst@ahbl.com Renton High School Phase 1 LUA25-000343 400 S 2nd St, Renton, WA 98057 000720-0060 & 42 other parcels FOR APPROVAL C26000333 2215 N 20th St, Tacoma, WA 98403 Page 15 of 16 Ref 8-H Bond Quantity Worksheet SECTION III. BOND WORKSHEET Version 1/2/2026 Printed 6/11/2026 Technical Information Report New Renton High School Project No. 2230388.10 Appendix H Operations 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-6 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. 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 growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non- floatables). No trash or debris in vault. Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Inlet/Outlet Pipes 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. Damaged inlet/outlet pipes 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. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-7 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole (cont.) 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. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can be opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure 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 structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. 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 structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and 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 structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure 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 structure 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. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damaged FROP-T T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-9 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED FROP-T Section (cont.) Damaged FROP-T (cont.) Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing cleanout gate Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing orifice plate Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions to orifice plate Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions to overflow pipe Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip of overflow pipe Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design 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. 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 (If applicable) 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. 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-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-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-15 NO. 9 – FENCING MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Erosion or holes under fence Erosion or holes more than 4 inches high and 12-18 inches wide permitting access through an opening under a fence. No access under the fence. Wood Posts, Boards and Cross Members Missing or damaged parts Missing or broken boards, post out of plumb by more than 6 inches or cross members broken No gaps on fence due to missing or broken boards, post plumb to within 1½ inches, cross members sound. Weakened by rotting or insects Any part showing structural deterioration due to rotting or insect damage All parts of fence are structurally sound. Damaged or failed post foundation Concrete or metal attachments deteriorated or unable to support posts. Post foundation capable of supporting posts even in strong wind. Metal Posts, Rails and Fabric Damaged parts Post out of plumb more than 6 inches. Post plumb to within 1½ inches. Top rails bent more than 6 inches. Top rail free of bends greater than 1 inch. Any part of fence (including post, top rails, and fabric) more than 1 foot out of design alignment. Fence is aligned and meets design standards. Missing or loose tension wire. Tension wire in place and holding fabric. Deteriorated paint or protective coating Part or parts that have a rusting or scaling condition that has affected structural adequacy. Structurally adequate posts or parts with a uniform protective coating. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 6/22/2022 2022 City of Renton Surface Water Design Manual A-16 NO. 10 – GATES/BOLLARDS/ACCESS BARRIERS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Chain Link Fencing Gate Damaged or missing members Missing gate. Gates in place. Broken or missing hinges such that gate cannot be easily opened and closed by a maintenance person. Hinges intact and lubed. Gate is working freely. Gate is out of plumb more than 6 inches and more than 1 foot out of design alignment. Gate is aligned and vertical. Missing stretcher bar, stretcher bands, and ties. Stretcher bar, bands, and ties in place. Locking mechanism does not lock gate Locking device missing, non-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Openings in fabric Openings in fabric are such that an 8-inch diameter ball could fit through. Fabric mesh openings within 50% of grid size. Bar Gate Damaged or missing cross bar Cross bar does not swing open or closed, is missing or is bent to where it does not prevent vehicle access. Cross bar swings fully open and closed and prevents vehicle access. Locking mechanism does not lock gate Locking device missing, non-functioning or does not link to all parts. Locking mechanism prevents opening of gate. Support post damaged Support post does not hold cross bar up. Cross bar held up preventing vehicle access into facility. Bollards Damaged or missing bollards Bollard broken, missing, does not fit into support hole or hinge broken or missing. No access for motorized vehicles to get into facility. Bollards do not lock Locking assembly or lock missing or cannot be attached to lock bollard in place. No access for motorized vehicles to get into facility. Boulders Dislodged boulders Boulders not located to prevent motorized vehicle access. No access for motorized vehicles to get into facility. Evidence of vehicles circumventing boulders Motorized vehicles going around or between boulders. No access for motorized vehicles to get into facility. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-17 NO. 11 – GROUNDS (LANDSCAPING) MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. 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 growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Trees and Shrubs Hazard tree identified Any tree or limb of a tree identified as having a potential to fall and cause property damage or threaten human life. A hazard tree identified by a qualified arborist must be removed as soon as possible. No hazard trees in facility. Damaged tree or shrub identified Limbs or parts of trees or shrubs that are split or broken which affect more than 25% of the total foliage of the tree or shrub. Trees and shrubs with less than 5% of total foliage with split or broken limbs. Trees or shrubs that have been blown down or knocked over. No blown down vegetation or knocked over vegetation. Trees or shrubs free of injury. Trees or shrubs which are not adequately supported or are leaning over, causing exposure of the roots. Tree or shrub in place and adequately supported; dead or diseased trees removed. BIOPOD SYSTEM™ Inspection & Maintenance Guide with StormMix Media™ DESCRIPTION The BioPod™ Biofilter System (BioPod) is a storm water biofiltration treatment system used to remove pollutants from storm water runoff. Impervious surfaces and other urban and suburban landscapes generate a variety of contaminants that can enter storm water and pollute downstream receiving waters unless treatment is provided. The BioPod system uses proprietary StormMix™ biofiltration media to capture and retain pollutants including total suspended solids (TSS), metals, nutrients, gross solids, trash and debris as well as petroleum hydrocarbons. FUNCTION The BioPod system uses engineered, high-flow rate filter media to remove storm water pollutants, allowing for a smaller footprint than conventional bioretention systems. Contained within a compact precast concrete vault, the BioPod system consists of a biofiltration chamber and an optional integrated high-flow bypass. The biofiltration chamber is filled with horizontal layers of aggregate, biofiltration media and mulch. Storm water passes vertically down through the mulch and biofiltration media for treatment. The mulch provides pretreatment by retaining most of the solids or sediment. The biofiltration media provides further treatment by retaining finer sediment and dissolved pollutants. The aggregate allows the media bed to drain evenly for discharge through an underdrain pipe or by infiltration. INSPECTION & MAINTENANCE OVERVIEW State and local regulations require all storm water management systems to be inspected on a regular basis and maintained as necessary to ensure performance and protect downstream receiving waters. Without maintenance, excessive pollutant buildup can limit system performance by reducing the operating capacity of the system and increasing the potential for scouring of pollutants during periods of high flow. Some configurations of the BioPod may require periodic irrigation to establish and maintain vegetation. Vegetation will typically become established about two years after planting. Irrigation requirements are ultimately dependent on climate, rainfall and the type of vegetation selected. INSPECTION & MAINTENANCE FREQUENCY Periodic inspection is essential for consistent system performance and is easily completed. Inspection is typically conducted a minimum of twice per year, but since pollutant transport and deposition varies from site to site, a site- specific maintenance frequency should be established during the first two or three years of operation. BIOPOD™ BIOFILTER WITH STORMMIX™ BIOFILTRATION MEDIA INSPECTION EQUIPMENT The following equipment is helpful when conducting BioPod inspections: | Recording device (pen and paper form, voice recorder, iPad, etc.) | Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) | PPE as required for entry | Traffic control equipment (cones, barricades, signage, flagging, etc.) | Manhole hook or pry bar | Flashlight | Tape measure | Socket INSPECTION PROCEDURES BioPod inspections are visual and are conducted without entering the unit. To complete an inspection, safety measures including traffic control should be deployed before the access covers or tree grates are removed. Once the covers have been removed, the following items should be checked and recorded (see form provided on page 6) to determine whether maintenance is required: | If the BioPod unit is equipped with an internal bypass, inspect the inlet rack (or inlet chamber on underground units) and outlet chamber and note whether there are any broken or missing parts. In the unlikely event that internal parts are broken or missing, contact Oldcastle Storm water at (800) 579-8819 to determine appropriate corrective action. | Note whether the curb inlet, inlet pipe, or inlet rack is blocked or obstructed. | If the unit is equipped with an internal bypass, observe, quantify and record the accumulation of trash and debris in the inlet rack or inlet chamber. The significance of accumulated trash and debris is a matter of judgment. Often, much of the trash and debris may be removed manually at the time of inspection if a separate maintenance visit is not yet warranted. | If it has not rained within the past 24 hours, note whether standing water is observed in the biofiltration chamber. | Finally, observe, quantify and record presence of invasive vegetation and the amount of trash and debris and sediment load in the biofiltration chamber. Erosion of the mulch and biofiltration media bed should also be recorded. Often, much of the invasive vegetation and trash and debris may be removed manually at the time of inspection if a separate maintenance visit is not yet warranted. Sediment load may be rated light, medium or heavy depending on the conditions. Loading characteristics may be determined as follows: • Light sediment load – sediment is difficult to distinguish among the mulch fibers at the top of the mulch layer; the mulch appears almost new. • Medium sediment load – sediment accumulation is apparent and may be concentrated in some areas; probing the mulch layer reveals lighter sediment loads under the top 1” of mulch. • Heavy sediment load – sediment is readily apparent across the entire top of the mulch layer; individual mulch fibers are difficult to distinguish; probing the mulch layer reveals heavy sediment load under the top 1” of mulch. www.oldcastleinfrastructure.com | (800) 735-5566 MAINTENANCE INDICATORS Maintenance should be scheduled if any of the following conditions are identified during inspection: | The concrete structure is damaged or the tree grate or access cover is damaged or missing | The inlet obstructed | Standing water is observed in the biofiltration chamber more than 24 hours after a rainfall event (use discretion if the BioPod is located downstream of a storage system that attenuates flow) | Trash and debris in the inlet rack cannot be easily removed at the time of inspection | Trash and debris, invasive vegetation or sediment load in the biofiltration chamber is heavy or excessive erosion has occurred MAINTENANCE EQUIPMENT The following equipment is helpful when conducting BioPod maintenance: MAINTENANCE PROCEDURES Maintenance should be conducted during dry weather when no flows are entering the system. In most cases, maintenance may be conducted without entering. Entry may be required to maintain BioPod Underground units, depending on system depth. Once safety measures such as traffic control are deployed, the access covers may be removed and the following activities may be conducted to complete maintenance: | Remove all trash and debris from the curb inlet and inlet rack manually or by using a vacuum truck as required. | Remove all trash and debris and invasive vegetation from the biofiltration chamber manually or by using a vacuum truck as required. | If the sediment load is medium or light but erosion of the biofiltration media bed is evident, redistribute the mulch with a rake or replace missing mulch as appropriate. If erosion persists, rocks may be placed in the eroded area to help dissipate energy and prevent recurring erosion. | If the sediment load is heavy, remove the mulch layer using a hoe, rake, shovel and bucket, or by using a vacuum truck as required. If the sediment load is particularly heavy, inspect the surface of the biofiltration media once the mulch has been removed. If the media appears clogged with sediment, remove and replace one or two inches of biofiltration media prior to replacing the mulch* layer. | Prune vegetation as appropriate and replace damaged or dead plants as required. | Replace the tree grate and/or access covers and sweep the area around the BioPod to leave the site clean. | All material removed from the BioPod during maintenance must be disposed of in accordance with local environmental regulations. In most cases, the material may be handled in the same manner as disposal of material removed from sumped catch basins or manholes. | Suitable clothing (appropriate footwear, gloves, hardhat, safety glasses, etc.) | PPE as required for entry | Traffic control equipment (cones, barricades, signage, flagging, etc.) | Manhole hook or pry bar | Flashlight | Tape measure | Rake, hoe, shovel and broom | Bucket | Pruners | Vacuum truck (optional) | Socket BIOPOD SURFACE www.oldcastleinfrastructure.com | (800) 735-5566 * Natural, shredded hardwood mulch should be used in the BioPod. Timely replacement of the mulch layer according to the maintenance indicators described above should protect the biofiltration media below the mulch layer from clogging due to sediment accumulation. However, whenever the mulch is replaced, the BioPod should be visited 24 hours after the next major storm event to ensure that there is no standing water in the biofiltration chamber. Standing water indicates that the biofiltration media below the mulch layer is clogged and must be replaced. Please contact Oldcastle Infrastructure at (800) 579-8819 to purchase the proprietary StormMix™ biofiltration media. BIOPOD TREE BIOPOD PLANTER BIOPOD UNDERGROUND BIOPOD INSPECTION & MAINTENANCE LOG BioPod Model Inspection Date Location GOOD YES YES YES YES YES LIGHT YES YES - Schedule Maintenance DAMAGED NO NO NO NO NO MEDIUM NO NO - Schedule Re-Inspection MISSING HEAVY Condition of Internal Components Curb Inlet or Inlet Rack Blocked Standing Water in Biofiltration Chamber Trash and Debris in Inlet Rack Trash and Debris in Biofiltration Chamber Invasive Vegetation in Biofiltration Chamber Sediment in Biofiltration Chamber Erosion in Biofiltration Chamber Maintenance Requirements NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: NOTES: www.oldcastleinfrastructure.com | (800) 735-5566 NOTES Filterra Vault Owner’s Manual (Precast Vault Configurations) ® Bioretention Systems ENGINEERED SOLUTIONS This Owner’s Manual applies to all precast Filterra Configurations, including Filterra Bioscape Vault and Filterra HC. www.ContechES.com/filterra | 800-338-11222 Table of Contents Introduction ................................................................................3 Activation Overview .....................................................................3 Filterra Plant Selection Overview ...................................................5 Warranty Overview ......................................................................5 Routine Maintenance Guidelines...................................................5 Maintenance Visit Procedure .........................................................8 Plant Care ................................................................................10 Appendix 1 – Activation Package ................................................11 Appendix 2 – Filterra Tree Grate Opening Expansion Procedure..... 18 ® Bioretention Systems ENGINEERED SOLUTIONS www.ContechES.com/filterra | 800-338-1122 3 Introduction Thank you for your purchase of the Filterra® Bioretention System. Filterra is a specially engineered stormwater treatment system incorporating high performance biofiltration media to remove pollutants from stormwater runoff. The system’s biota (vegetation and soil microorganisms) then further breakdown and absorb captured pollutants. All components of the system work together to provide a sustainable long-term solution for treating stormwater runoff. The Filterra system has been delivered to you with protection in place to resist intrusion of construction related sediment which can contaminate the biofiltration media and result in inadequate system performance. These protection devices are intended as a best practice and cannot fully prevent contamination. It is the purchaser’s responsibility to provide adequate measures to prevent construction related runoff from entering the Filterra system. Included with your purchase is Activation of the Filterra system by the manufacturer as well as a 1-year warranty from delivery of the system and a final site assessment of unit condition (mulch replacement, debris removal, and pruning of vegetation, if applicable) scheduled between 6 and 12 months after activation, upon request. Design and Installation Each project presents different scopes for the use of Filterra systems. Information and help may be provided to the design engineer during the planning process. Correct Filterra box sizing (by rainfall region) is essential to predict pollutant removal rates for a given area. The engineer shall submit calculations for approval by the local jurisdiction. The contractor is responsible for the correct installation of Filterra units as shown in approved plans. A comprehensive installation manual is available at www.ContechES.com. Activation Overview Activation of the Filterra system is a procedure completed by the manufacturer to place the system into working condition. This involves the following items: • Removal of construction runoff protection devices. • Planting of the system’s vegetation (provided by the purchaser) where applicable. • Placement of pretreatment mulch layer using mulch acceptable for use in Filterra systems. Activation MUST be provided by the manufacturer to ensure proper site conditions are met for Activation, proper installation of the vegetation (where applicable), and use of pretreatment mulch acceptable for use in Filterra systems. More information is available in the Filterra Activation Package. Minimum Requirements The minimum requirements for Rapterra Activation can be found in Appendix 1 (page 12). The Rapterra Activation Package is available on the Contech website (www.ContechES.com/Rapterra) and ensures that the proper conditions are met for Contech to perform the Activation service. If vegetation is specified or required, vegetation meeting Contech’s requirements must be provided at time of Activation. If the site does not meet the conditions required for Activation, or acceptable vegetation is not provided by the purchaser at time of Activation, a charge of $1,500 will be invoiced to the purchaser. www.ContechES.com/filterra | 800-338-11224 Filterra Plant Selection Overview A Plant List is available on the Contech website highlighting recommended plants for Filterra systems in your area for systems specified with and/or requiring vegetation. Keep in mind that plants are subject to availability due to seasonality and required minimum size for the Filterra system. Plants installed in the Filterra system are container plants (max 15 gallon) from nursery stock and will be immature in height and spread at Activation. It is the responsibility of the owner to provide adequate irrigation when necessary to the plant of the Filterra system. More information is available in the Filterra Activation Package. Warranty Overview Refer to the Contech Engineered Solutions LLC Stormwater Treatment System LIMITED WARRANTY for further information. The following conditions may void the Filterra system’s warranty and waive the manufacturer provided Activation and Final Site Assessment services: • Unauthorized activation or performance of any of the items listed in the activation overview • Any tampering, modifications or damage to the Filterra system or runoff protection devices • Removal of any Filterra system components • Failure to prevent construction related runoff from entering the Filterra system • Failure to properly store and protect any Filterra components (including media and underdrain stone) that may be shipped separately from the vault Final Site Assessment With proper routine maintenance, the biofiltration media within the Filterra system should last as long as traditional bioretention media. A final site assessment is included by the manufacturer, upon request, on all Filterra systems between 6 and 12 months after activation. This includes a final assessment of unit condition, debris removal, mulch replacement, and pruning of vegetation, where applicable. More information is provided in the Operations and Maintenance Guidelines. Some Filterra systems also contain pretreatment or outlet bays. Depending on site pollutant loading, these bays may require periodic removal of debris, however this is not included in the final site assessment, and would likely not be required within the first year of operation. These services, as well as routine maintenance outside of the included first year, can be provided by certified maintenance providers listed on the Contech website. Training can also be provided to other stormwater maintenance or landscape providers. www.ContechES.com/filterra | 800-338-1122 5 Why Maintain? All stormwater treatment systems require maintenance for effective operation. This necessity is often incorporated in your property’s permitting process as a legally binding BMP maintenance agreement. Other reasons to maintain are: • Avoiding legal challenges from your jurisdiction’s maintenance enforcement program. • Prolonging the expected lifespan of your Filterra media. • Avoiding more costly media replacement. • Helping reduce pollutant loads leaving your property. Simple maintenance of the Filterra is required to continue effective pollutant removal from stormwater runoff before discharge into downstream waters. This procedure will also extend the longevity of the living biofilter system. The unit will recycle and accumulate pollutants within the biomass, but is also subjected to other materials entering the inlet. This may include trash, silt and leaves etc. which will be contained above the mulch layer. Too much silt may inhibit the Filterra’s flow rate, which is the reason for site stabilization before activation. Regular replacement of the mulch stops accumulation of such sediment. When to Maintain? Maintenance visits are scheduled seasonally; the spring visit aims to clean up after winter loads including salts and sands while the fall visit helps the system by removing excessive leaf litter. It has been found that in regions which receive between 30-50 inches of annual rainfall, (2) two visits are generally required; in regions with less rainfall often only (1) one visit per annum is sufficient. Varying land uses can affect maintenance frequency. Contributing drainage areas which are subject to new development wherein the recommended erosion and sediment control measures have not been implemented may require additional maintenance visits. Some sites may be subjected to extreme sediment or trash loads, requiring more frequent maintenance visits. This is the reason for detailed notes of maintenance actions per unit, helping the Supplier and Owner predict future maintenance frequencies, reflecting individual site conditions. Owners must promptly notify the maintenance provider of any damage to the plant(s), which constitute(s) an integral part of the bioretention technology. www.ContechES.com/filterra | 800-338-11226 Exclusion of Services Clean up due to major contamination such as oils, chemicals, toxic spills, etc. will result in additional costs and are not included as part of the final site assessment. Should a major contamination event occur the Owner must block off the outlet pipe of the Filterra (where the cleaned runoff drains to, such as drop inlet) and block off the throat of the Filterra. The Supplier should be informed immediately. Maintenance Visit Summary Each maintenance visit consists of the following simple tasks (detailed instructions below). 1. Inspection of Filterra and surrounding area 2. Removal of tree grate or access cover and erosion control stones 3. Removal of debris, trash and mulch 4. Mulch replacement 5. Plant health evaluation and pruning or replacement as necessary 6. Clean area around Filterra 7. Complete paperwork Maintenance Tools, Safety Equipment and Supplies Ideal tools include: camera, bucket, shovel, broom, pruners, hoe/rake, and tape measure. Appropriate Personal Protective Equipment (PPE) should be used in accordance with local or company procedures. This may include impervious gloves where the type of trash is unknown, high visibility clothing and barricades when working in close proximity to traffic and also safety hats and shoes. A T-Bar or crowbar should be used for moving the tree grates (up to 170 lbs ea.). Most visits require minor trash removal and a full replacement of mulch. See below for actual number of bagged mulch that is required in each media bay size. Mulch should be a double shredded, hardwood variety. Some visits may require additional Filterra engineered soil media available from the Supplier. Box Length Box Width Filter Surface Area (ft²)Volume at 3” (ft³)# of 2 ft³ Mulch Bags 4 4 16 4 2 6 4 24 6 3 8 4 32 8 4 6 6 36 9 5 8 6 48 12 6 10 6 60 15 8 12 6 72 18 9 13 7 91 23 12 Other sizes not listed - 1 bag per 4 ft2 of media. www.ContechES.com/filterra | 800-338-1122 7 1. Inspection of Filterra and surrounding area • Record individual unit before maintenance with photograph (numbered). Record on Maintenance Report (see example in this document) the following: 2. Removal of tree grate or access cover and erosion control stones • Remove cast iron grates or covers for access into Filterra box. • Dig out silt (if any) and mulch and remove trash & foreign items. 3. Removal of debris, trash and mulch • After removal of mulch and debris, measure distance from the top of the Filterra engineered media soil to the top of the top slab. Compare the measured distance to the distance shown on the approved Contract Drawings for the system. Add Filterra media (not top soil or other) to bring media up as needed to distance indicated on drawings. Record on Maintenance Report the following: Standing Water yes | no Damage to Box Structure yes | no Damage to Grate yes | no Is Bypass Clear yes | no If yes answered to any of these observations, record with close-up photograph (numbered). Record on Maintenance Report the following: Silt/Clay yes | no Cups/ Bags yes | no Leaves yes | no Buckets Removed ________ Record on Maintenance Report the following: Distance to Top of Top Slab (inches) ________ Inches of Media Added ________ Maintenance Visit Procedure Keep sufficient documentation of maintenance actions to predict location specific maintenance frequencies and needs. An example Maintenance Report is included in this manual. www.ContechES.com/filterra | 800-338-11228 4. Mulch replacement • Add double shredded mulch evenly across the entire unit to a depth of 3”. • Refer to Filterra Mulch Specifications for information on acceptable sources. • Ensure correct repositioning of erosion control stones by the Filterra inlet to allow for entry of trash during a storm event. • Replace Filterra grates or covers correctly using appropriate lifting or moving tools, taking care not to damage the plant, if applicable. 5. Plant health evaluation and pruning or replacement as necessary • Examine the plant’s health, if applicable, and replace if necessary. • Prune as necessary to encourage growth in the correct directions 6. Clean area around Filterra • Clean area around unit and remove all refuse to be disposed of appropriately. 7. Complete paperwork • Deliver Maintenance Report. • Some jurisdictions may require submission of maintenance reports in accordance with approvals. It is the responsibility of the Owner to comply with local regulations. Record on Maintenance Report the following: Height above Grate _____________________(ft) Width at Widest Point _____________________(ft) Health healthy | unhealthy Damage to Plant yes | no Plant Replaced yes | no www.ContechES.com/filterra | 800-338-1122 9 Plant Care for Filterra® Systems w/ Vegetation Specified and/or Required After Activation, the Contractor is responsible for proper care of the vegetation until the site is handed over to the Owner. After that, it is the Site Owner’s responsibility to care for the vegetation. Contech recommends the following care for the plants: 1. To prevent transplant shock (especially if planting takes place in the hot season), it may be necessary to prune some of the foliage to compensate for reduced root uptake capacity. This is accomplished by pruning away some of the smaller secondary branches or a main scaffold branch if there are too many. Too much foliage relative to the root ball can dehydrate and damage the plant. 2. Plant staking may be required. 3. With all trees/shrubs, remove dead, diseased, crossed/ rubbing, sharply crotched branches or branches growing excessively long or in wrong direction compared to majority of branches. 4. Contech recommends irrigation of the Filterra® Vegetation. The following guidance will help to ensure the vegetation is properly irrigated. Irrigation Recommendations: • Each Filterra® system must receive adequate irrigation to ensure survival of the living system during periods of drier weather. • Irrigation sources include rainfall runoff from downspouts and/or gutter flow, applied water through the tree grate or in some cases from an irrigation system with emitters installed during construction. • At Activation: Apply about one (cool climates) to two (warm climates) gallons of water per inch of trunk diameter over the root ball. • During Establishment: In common with all plants, each Filterra® plant will require more frequent watering during the establishment period. One inch of applied water per week for the first three months is recommended for cooler climates (2 to 3 inches for warmer climates). If the system is receiving rainfall runoff from the drainage area, then irrigation may not be needed. Inspection of the soil moisture content can be evaluated by gently brushing aside the mulch layer and feeling the soil. Be sure to replace the mulch when the assessment is complete. Irrigate as needed**. • Established Plants: Established plants have fully developed root systems and can access the entire water column in the media. Therefore irrigation is less frequent but requires more applied water when performed. For a mature system assume 3.5 inches of available water within the media matrix. Irrigation demand can be estimated as 1” of irrigation demand per week. Therefore if dry periods exceed 3 weeks, irrigation may be required. ** Five gallons per square yard approximates 1 inch of water. Therefore for a 6’ x 6 foot Filterra® approximately 20-60 gallons of applied water is needed. To ensure even distribution of water it needs to be evenly sprinkled over the entire surface of the filter bed, with special attention to make sure the root ball is completely wetted. NOTE: if needed, measure the time it takes to fill a five gallon bucket to estimate the applied water flow rate. Then calculate the time needed to irrigate the Filterra®, For example is the flow rate of the sprinkler is 5 gallons/minute then it would take 12 minutes to irrigate a 6’x6’ filter. Plant Replacement: In some cases, plants will require replacement. Please follow the procedures below to ensure a properly functioning Filterra® system. 1. Remove the existing plant, and leave as much of the Filterra® media in place as possible. 2. Select a replacement per the Filterra® Activation Package. 3. Prior to removing the plant from the container, ensure the soil moisture is sufficient to maintain the integrity of the root ball. If needed, pre-wet the container plant. 4. Cut away any roots which are growing out of the container drain holes. 5. Plant(s) should be carefully removed from the pot by gently pounding on the sides of the container with the fist to loosen root ball. Then carefully slide out. Do not lift plant(s) by trunk as this can break roots and cause soil to fall off. Extract the root ball in a horizontal position and support it to prevent it from breaking apart. Alternatively, the pot can be cut away to minimize root ball disturbance. 6. Excavate a hole with a diameter 4” greater than the root ball, gently place the plant(s). 7. Plant the tree/shrub/grass with the top of the root ball 1” above surrounding media to allow for settling. 8. All plants should have the main stem centered in the tree grate (where applicable) upon completion of installation. 9. Reinstall or add mulch to a depth of 3” per Contech’s mulch specifications for Filterra® systems. www.ContechES.com/filterra | 800-338-112210 Maintenance Checklist Filterra Inspection & Maintenance Log Filterra System Size/Model: _____________________________Location: ____________________________________________ Drainage System Failure Problem Conditions to Check Condition that Should Exist Actions Inlet Excessive sediment or trash accumulation. Accumulated sediments or trash impair free flow of water into Filterra. Inlet should be free of obstructions allowing free distributed flow of water into Filterra. Sediments and/or trash should be removed. Mulch Cover Trash and floatable debris accumulation.Excessive trash and/or debris accumulation.Minimal trash or other debris on mulch cover. Trash and debris should be removed and mulch cover raked level. Ensure bark nugget mulch is not used. Mulch Cover “Ponding” of water on mulch cover. “Ponding” in unit could be indicative of clogging due to excessive fine sediment accumulation or spill of petroleum oils. Stormwater should drain freely and evenly through mulch cover. Recommend contact manufacturer and replace mulch as a minimum. Vegetation (where applicable)Plants not growing or in poor condition. Soil/mulch too wet, evidence of spill. Incorrect plant selection. Pest infestation. Vandalism to plants. Plants should be healthy and pest free.Contact manufacturer for advice. Vegetation (where applicable)Plant growth excessive. Plants should be appropriate to the species and location of Filterra. Trim/prune plants in accordance with typical landscaping and safety needs. Structure Structure has visible cracks. Cracks wider than 1/2 inch or evidence of soil particles entering the structure through the cracks. Vault should be repaired. Maintenance is ideally to be performed twice annually. Date Mulch & Debris Removed Depth of Mulch Added Mulch Brand Height of Vegetation Above Grate (if applicable) Vegetation Species (if applicable) Issues with System Comments 1/1/17 5 – 5 gal Buckets 3”Lowe’s Premium Brown Mulch 4’Galaxy Magnolia - Standing water in downstream structure - Removed blockage in downstream structure www.ContechES.com/filterra | 800-338-1122 11 Filterra Activation Package | Page 1 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® The Filterra system will be (or has been) delivered to you with protection in place to resist intrusion of construction related sediment which can contaminate the biofiltration media and result in inadequate system performance. These protection devices are intended as a best practice and cannot fully prevent contamination. It is the purchaser’s responsibility to provide adequate measures to prevent construction related runoff from entering the Filterra system. Included with your purchase is Activation of the Filterra system by the manufacturer as well as a 1-year warranty from delivery of the system and a Final Site Assessment (assessment of unit condition, mulch replacement, debris removal, and pruning of vegetation if applicable) scheduled between 6 months and 1 year after Activation, upon request. Activation of the Filterra system is a procedure completed by the manufacturer to place the system into working condition. This involves the following items: • Removal of construction runoff protection devices • Planting of the system’s vegetation (provided by the purchaser where specified and/or required) • Placement of pretreatment mulch layer using mulch acceptable for use in Filterra systems. Activation MUST be provided by the manufacturer to ensure proper site conditions are met for Activation, proper installation of the vegetation (where applicable), and use of pretreatment mulch acceptable for use in Filterra systems. The purchaser should request Activation from Contech after the site is stabilized, but prior to turning over the site to the owner. Please allow 1-2 weeks to schedule Activation. The purchaser must ensure that the site is acceptable for Filterra Activation. A checklist (included as page 3 of this document must be completed and submitted to the Contech Activation Coordinator. The minimum 4 requirements for Filterra Activation are as follows: 1. If vegetation is specified and/or required, the purchaser must have sourced vegetation meeting the requirements outlined in “Plant Selection for Filterra Systems” starting on page 4 of this document. FILTERRA® VAULT ACTIVATION PACKAGE Appendix 1 – Filterra® Vault Activation Package www.ContechES.com/filterra | 800-338-112212 Filterra Activation Package | Page 2 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® 2. The site landscaping must be fully stabilized, i.e. full landscaping installed and some grass cover (not just straw and seed) is required to reduce sediment transport. Construction debris and materials should be removed from surrounding area. 3. Final paving must be completed. Final paving ensures that paving materials will not enter and contaminate the Filterra system during the paving process, and that the plant will receive runoff from the drainage area, assisting with plant survival for the Filterra system. 4. Where curb inlets are included as part of the Filterra system, Filterra throat opening should be at least 4” clear in order to ensure adequate capacity for inflow and debris. www.ContechES.com/filterra | 800-338-1122 13 Filterra Activation Package | Page 3 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® Filterra® Vault Activation Checklist Project Name: ________________________________________Company: ______________________________________________ Site Contact Name: _______________________________________Site Contact Phone/Email: ____________________________ Site Owner/End User Name: _________________________Site Owner/End User Phone/Email: ____________________________ Preferred Activation Date: ___________________________________(provide 2 weeks minimum from date this form is submitted) Site Designation Top Opening Type Final Pavement Complete Landscaping Complete / Grass Emerging Construction materials / Piles / Debris Removed Throat Opening Measures 4” Min. Height (where applicable) Vegetation Sourced by Contractor (where applicable) Tree Grate Full Grate (No tree opening) Bioscape Vault (Open Planter) Verified Verified Verified Verified Species on FT Plant List Container Grown (15 gal. max) 4’ Tall Min. (Tree grate units only) ____ Qty provided Tree Grate Full Grate (No tree opening) Bioscape Vault (Open Planter) Verified Verified Verified Verified Species on FT Plant List Container Grown (15 gal. max) 4’ Tall Min. (Tree grate units only) ____ Qty provided Tree Grate Full Grate (No tree opening) Bioscape Vault (Open Planter) Verified Verified Verified Verified Species on FT Plant List Container Grown (15 gal. max) 4’ Tall Min. (Tree grate units only) ____ Qty provided Tree Grate Full Grate (No tree opening) Bioscape Vault (Open Planter) Verified Verified Verified Verified Species on FT Plant List Container Grown (15 gal. max) 4’ Tall Min. (Tree grate units only) ____ Qty provided NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for activation AND/OR acceptable plants are not provided by the contractor. ONLY Contech authorized representatives can perform activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. Attach additional sheets as necessary. Signature Date ENGINEERED SOLUTIONS www.ContechES.com/filterra | 800-338-112214 Filterra Activation Package | Page 4 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® Planting Selection for Filterra® Vault Systems Specifying and/or Requiring Plants Vegetation is recommended in Filterra for proper long-term performance. As indicated in the Activation Package, the Contractor is responsible for sourcing the proper vegetation prior to Activation. Contech or a Contech representative will install the vegetation during the Activation process. Contractors should identify the Top Opening style for each Filterra requiring Activation on the Activation Checklist. Contech offers three types, which are detailed on page 5 of this document: • Vault with Tree Grate • Vault with Full Grate • Bioscape / Open Planter Contractors must ensure the vegetation meets the following 4 requirements: 1. Select plant(s) as specified in the engineering plans and specifications AND that are listed on Contech’s Configuration Specific Plant Lists**. 2. All plants MUST be container-grown in nursery containers no larger than 15 gallons. Crated and/or Ball/Burlap plants are NOT permitted. 3. For Vaults with Tree Grates, plant height must be 4’ Minimum, from soil surface to top of plant. 4. Provide plant quantities per the following guidance: • Vault with Tree Grate – 1 per Tree Grate • Vault with Full Grate – 4-5 Small or Extra Small Grasses per Full Grate • Bioscape – Quantities should be selected based on plant palette options found starting on page 6 of this document. If Contech or Contech’s representative shows up for Activation and any of the 4 requirements above are not met, Activation cannot be performed and the Contractor will be billed a $1,500 Unprepared Site fee*. Some additional vegetation recommendations for the best possible Activation and Installation are as follows: • Select plant(s) with full root development but not to the point where root bound. • For Filterra systems with a Tree Grate, select plants with taller trunks. Lower branches can be pruned away provided there are sufficient branches above the grate for tree or shrub development. • For Filterra systems with a Tree Grate, plant(s) should have a single trunk at installation. • Plant species shall not have a mature height greater than 30 feet. ** In some cases, Contech may consider alternate plant species as approved by the Product Manager. Please list the plant name in the space below and submit this sheet to your Contech Activation Coordinator. If the plant species is approved, either the Product Manager or the Activation Coordinator will sign the form and return to you for inclusion with your Activation Checklist. Requested Plant Species: ___________________________________________Approved: _______________________________ Date: ____________________________________ www.ContechES.com/filterra | 800-338-1122 15 Filterra Activation Package | Page 5 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® Figure 1a. Filterra with Tree Grate Drawing Figure 2a. Filterra with Full Grate Drawing Figure 3a. Filterra Bioscape Vault Drawing Figure 1b. Filterra with Tree Grate Photo (not yet planted) Figure 2b. Filterra with Full Grate Photo Figure 3b. Filterra Bioscape Vault Photo Filterra® Top Opening Examples Filterra® Vault with Tree Grate Filterra® Vault with Full Grate Filterra® Bioscape Vault www.ContechES.com/filterra | 800-338-112216 Filterra Activation Package | Page 6 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® Filterra® Bioscape Vault Plant Palettes KEY: (refer to plant lists for species sizing) 4x4 Media Bay A. 3 A.5 A. 6 A. 6 A. 9 A. 12 A. 15 A. 20 B. 6 C. 3 D. 2 B. 1 B.2 B. 2 B. 2 B. 3 B. 3 B. 4 C. 1 C.1 C. 1 D. 1 D. 1 D. 1 D. 1 D. 1 C. 1 C. 2 C. 2 C. 2 4x6/6x4 Media Bay 4x8/8x4 & 4.5x7.83/7.83x4.5 Media Bay 6x6 Media Bay 6x8/8x6 Media Bay 6x10/10x6 & 8x8 Media Bay 6x12/12x6 Media Bay 7x13/13x7/12x8 & 14x8 Media Bay A. EXTRA SMALL GRASS • Up to 2’ mature spread • 1-2 gallon typical (1 gal. minimum) B. SMALL GRASS/SHRUB • 2’-4’ mature spread • 1-7 gallon typical C. MEDIUM SHRUB • 4’-6’ mature spread • 1-7 gallon typical D. LARGE SHRUB OR EXTRA LARGE SHRUB OR TREE • 6’ mature spread and greater, 30’ max. mature height • Up to 15 gallon maximum NOTE: For larger vaults and in-ground Filterra Bioscape systems, palettes can be scaled (i.e. Qty 6 of the 22x8 Palette can be used for a 1056 sf Filterra Bioscape). MIX & MATCH SUBSTITUTION OPTIONS: 1 Large Shrub or Extra Large Shrub or Tree • 2 Medium Shrubs • 4 Small Grass/SHrubs • 12 Extra Small Grasses 1 Medium Shrub • 2 Small Grass/Shrubs • 6 Extra Small Grasses 1 Small Grass/Shrub • 3 Extra Small Grasses www.ContechES.com/filterra | 800-338-1122 17 Filterra Activation Package | Page 7 * UNPREPARED SITE FEE NOTE: A charge of $1500.00 will be invoiced for each activation visit requested by customer where Contech determines that the site does not meet the conditions required for Activation AND/OR acceptable plants (when specified and/or required) are not provided by the contractor. ONLY Contech authorized representatives can perform Activation of Filterra systems; unauthorized activations will void the system warranty and waive manufacturer supplied activation and final inspection. ® A. 24 A. 28 A. 32 A. 36 B. 8 B. 8 B. 10 B. 10 C. 4 C. 4 C. 5 C. 5 D. 2 D. 2 D. 3 D. 3 16x8 & 15x9 Media Bay 18x8 Media Bay 20x8 Media Bay 22x8 Media Bay Appendix 2 – Filterra® Tree Grate Opening Expansion Procedure The standard grates used on all Filterra configurations that employ Tree Grates are fabricated with a 6” opening that is designed with a breakaway section that can be removed, allowing the grate opening to be expanded to 12” as the tree matures and the trunk widens. The following tools are required to expand the opening: • Mini sledgehammer (3 lb. or greater) • Safety Glasses / Goggles The following guidelines should be followed to properly expand the tree opening from 6” to 12”: 1. Remove the grate from the Filterra frame, place it flat on a hard surface, and support the grate by stepping on the edge or using other weighted items such as a few mulch bags if this is being done during a Filterra maintenance event. Put on safety glasses/goggles. Align the mini sledgehammer as shown in the figure to the left. The head of the sledgehammer should be aimed just inside the wide cast iron bar between the larger grate section and the breakaway section. 2. Repeatedly hit the grate at this spot with the mini sledgehammer. 3. After several hits, the breakaway section should snap cleanly off of the larger grate section. Reinstall the grate into the Filterra grate frame. Recycle or dispose of the breakaway section per local guidelines. Notes ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ ___________________________________________________________________________________________________________ PDF 1/26 © 2026 Contech Engineered Solutions LLC, a QUIKRETE Company 9100 Centre Pointe Drive, Suite 400 West Chester, OH 45069 info@conteches.com | 800-338-1122 www.ContechES.com ALL RIGHTS RESERVED. PRINTED IN THE USA. NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY. APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS, AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION. CONTECH MAKES NO WARRANTY WHATSOEVER, EXPRESS OR IMPLIED, RELATED TO THE APPLICATIONS, MATERIALS, COATINGS, OR PRODUCTS DISCUSSED HEREIN. ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH’S CONDITIONS OF SALE (AVAILABLE AT WWW.CONTECHES.COM/COS) FOR MORE INFORMATION. ® Bioretention Systems ENGINEERED SOLUTIONS