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HomeMy WebLinkAboutRS_TIR_251229_APPROVED SITE ADDRESS PROJECT NO. DATE JURISDICTION 116th Ave SE Renton, Washington 22298 12/29/2025 City of Renton TECHNICAL INFORMATION REPORT PREPARED BY Harmony Ridge Trent Skoda, PE PREPARED FOR CLIENT ADDRESS Ichijo USA Co., Ltd. 1406 140th PL NE, Suite 104 Bellevue, WA 98007 T R E N T O N SK O D A 12/29/25 DEVELOPMENT ENGINEERING HBray 02/05/2026 Surface Water Enginering jfarah 02/05/2026 22298.001-DRNG TABLE OF CONTENTS 1.0 PROJECT OVERVIEW Figure 1.0.1 – Technical Information Report (TIR) Worksheet Figure 1.0.2 – Vicinity Map Figure 1.0.3 – Predeveloped Basin Map Figure 1.0.4 – Soil Survey Map Figure 1.0.5 – Assessor's Map Figure 1.0.6 – FEMA Map Figure 1.0.7 – Sensitive Area Map Figure 1.0.8 – Developed Basin Map Figure 1.0.9 – Downstream Basin Map 2.0 CONDITIONS AND REQUIREMENTS SUMMARY Figure 2.0.1 – Hearing Examiner’s Conditions of Approval and Responses 2.1 Analysis of the Core Requirements and Special Requirements 3.0 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 Existing Site Hydrology 4.2 Developed Site Hydrology 4.3 Performance Standards 4.4 Flow Control System Figure 4.4.1 – WWHM Detention Vault Calculations Figure 4.4.2 – WWHM Basin 2 & 3 Calculations Figure 4.4.3 – Storm Facility Layout 4.5 Water Quality System Figure 4.5.1 –Combined Water Quality Basin Map Figure 4.5.2 – Combined Water Quality Basin Calculation Figure 4.5.3 – Contech StormFilter Sizing Coordination Email Figure 4.5.4 – Contech StormFilter ZPG GULD 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Figure 5.0.1 – Conveyance Analysis Figure 5.0.2 – Backwater Analysis 22298.001-DRNG 6.0 SPECIAL REPORTS AND STUDIES 6.1 Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. updated July 3, 2023 6.2 Final Tree Protection Plan prepared by Washington Forestry Consultants, Inc. dated August 21, 2025 7.0 OTHER PERMITS 8.0 ESC ANALYSIS AND DESIGN 9.0 BOND QUANTITIES AND FACILITY SUMMARIES Figure 9.0.1 – Bond Quality Worksheet 10.0 OPERATIONS AND MAINTENANCE MANUAL Section 1.0 22298.001-DRNG 1.0 PROJECT OVERVIEW This section contains the following information: Figure 1.0.1 – Technical Information Report (TIR) Worksheet Figure 1.0.2 – Vicinity Map Figure 1.0.3 – Predeveloped Basin Map Figure 1.0.4 – Soil Survey Map Figure 1.0.5 – Assessor's Map Figure 1.0.6 – FEMA Map Figure 1.0.7 – Sensitive Area Map Figure 1.0.8 – Developed Basin Map Figure 1.0.9 – Downstream Basin Map 22298.001-DRNG 1.0 PROJECT OVERVIEW The Harmony Ridge project is a single-family residential project consisting of the development of an existing parcel in the City of Renton. The project includes approximately 6.24 acres of parcel area located on 15509 116th Ave SE. The proposed development will construct 20 single-family lots with associated roads, tracts, utilities, and stormwater facilities. The existing United Christian Church (UCC) buildings located near the northeast corner of the site will remain with this development. The project site is located within a portion of Section 20, Township 23 North, Range 5 East, Willamette Meridian, in the City of Renton, Washington. The property contains multiple buildings and a parking lot near the northeast corner of the site gaining access from 116th Ave SE. Aside from these existing developed areas, the site mostly consists of undisturbed forested area. There are no natural drainage courses of any kind on the property. Elevations range from 465 to 420 feet across the site with slopes ranging from approximately 2 to 25%. The USDA Web Soil Survey for this area shown in Figure 1.0.4 of this section indicates that the onsite soils are considered Alderwood gravelly sandy loam with 8 to 15 percent slopes and Alderwood material with 6 to 15 percent slopes. This soil type is typically comprised of glacial soils. The Geotechnical Engineering Study prepared by Earth Solutions NW, LLC identified the underlying native soil as glacial till deposits between the depths of 0.5 to 14 feet. These soils are considered infeasible for infiltration facilities per the Geotechnical Engineering Study included in Section 6.1 of this report. Onsite construction will include a public roadway with curb and gutter, sidewalk and planter strip, alley road for lot access and detention and water quality facilities. Additionally, stormwater catch basins, storm pipes, water mains and sewer utilities will be constructed onsite. Frontage improvements along 116th Ave SE will consist of roadway widening with vertical curb, planter strip and sidewalk. The offsite construction will consist of a utility access road connecting Tract A with Puget Dr SE. Stormwater runoff generated by the onsite impervious and pervious areas will be routed to an onsite detention vault located within Tract A and will be treated prior to discharging to the downstream conveyance system on Puget Dr SE. Runoff eventually flows into Thunder Hills Creek to the southwest. Water quality will be provided by a Stormfilter or approved equal located within the offsite access road downstream of the proposed detention vault. Stormwater runoff generated by a portion of Tract A downstream of the detention vault and the offsite impervious and pervious areas in the utility access road will be bypassed and also treated by the Stormfilter located within the access road. The storm drainage design is based on the 2022 City of Renton Surface Water Design Manual (2022 CORSWDM) which is an amended version of the 2021 King County Surface Water Design Manual (2021 KCSWDM). Please refer to Section 4.0 of this TIR for further details regarding the drainage facility design. 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 __________________ __________________ __________________ Ichijo USA Co., Ltd. (425) 497-0616 1406 140th Pl NE, Suite 104 Bellevue WA 98007 Barry Talkington Barghausen Consulting Engineers (425) 251-6222 Harmony Ridge 23 05 20 15509 116th Ave SE Renton WA, 98058 Lock and load retaining wall Figure 1.0.1 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-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 ______________________  _____________________________________ TBD TBD N/A Black River Basin (Thunder Hills Creek Sub Basin), Lower Cedar River (Ginger Creek Sub Basin) 2022 City of Renton Surface Water Design Manual ESC facilities including a temporary sediment pond REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 9 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Alderwood gravelly sandy loam Alderwood material 8-15%Low 8-15%Low Discharging to roadside ditch on Puget Dr SE tributary to Thunder Hills Creek Sub Basin 1 12/01/2022 Flow Control Duration Standard Matching Forested Site Conditions TBD TBD TBD TBD 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: Basic Sheet Flow Dispersion, perforated pipe connection N/A N/A N/A REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 9 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Discharging to catch basin on 116th Ave SE north of the site entrance, tributary to Ginger Creek Sub Basin 1 12/01/2022 Flow Control Duration Standard Matching Forested Site Conditions TBD TBD TBD TBD 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: N/A N/A N/A REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 9 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No 1 12/01/2022 Flow Control Duration Standard Matching Forested Site Conditions TBD TBD TBD TBD Discharging to catch basin on 116th Ave SE south of the site entrance, tributary to Ginger Creek Sub Basin 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: N/A N/A N/A 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 Vault Stormfilter Roof Downspout Connections 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 12/29/25 Horizontal: Scale: Vertical: For: Title: VICINITY MAP Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 vmap.cdr REFERENCE: MapQuest (2022) SITE Figure 1.0.2 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 PREDEVELOPED BASIN MAP 1 SCALE: 1"=50' 11 6 T H A V E S E R O L L I N G H I L L S A V E S E PUG E T D R S E CA M A S C I R S E SE 1 9 T H S T S E 1 9 T H S T ABE R D E E N A V E S E PREDEVELOPED BASIN MAP PREDEVELOPED BASIN 2 PREDEVELOPED BASIN 1 BASIN 1 SLOPE FORESTED (AC) FLOW CONTROL STANDARD FLAT 4.67 MOD 0.00 STEEP 0.00 TOTAL BASIN 4.67 UPSTREAM SLOPE FORESTED (AC) FLOW CONTROL STANDARD FLAT 0.09 MOD 0.00 STEEP 0.00 TOTAL BASIN 0.09 BASIN 2 SLOPE FORESTED (AC) FLOW CONTROL STANDARD FLAT 0.45 MOD 0.00 STEEP 0.00 TOTAL BASIN 0.45 BASIN 3 SLOPE FORESTED (AC) FLOW CONTROL STANDARD FLAT 0.09 MOD 0.00 STEEP 0.00 TOTAL BASIN 0.09 EX BUILDING UPSTREAM BASIN PREDEVELOPED BASIN 3 Figure 1.0.3 Horizontal: Scale: Vertical: For: Title: SOIL SURVEY MAP Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 soil.cdr HSG B B/D REFERENCE: USDA, Natural Resources Conservation Service LEGEND: SITE AgC = Alderwood gravelly sandy loam, 8-15% slopes AmC = Arents, Alderwood material, 6-15% slopes Figure 1.0.4 Horizontal: Scale: Vertical: For: Title: ASSESSOR MAP Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 amap.cdr SITE REFERENCE: King County Department of Assessments (July 2022) Figure 1.0.5 Horizontal: Scale: Vertical: For: Title: FEMA MAP Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 fema.cdr REFERENCE: Federal Emergency Management Agency (Portion of Map 53033C0979G, Aug. 2020) SITE LEGEND Areas determined to be outside the 0.2% annual chance floodplain.ZONE X OTHER AREAS Figure 1.0.6 Horizontal: Scale: Vertical: For: Title: SENSITIVE AREAS MAP Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 sens.cdr SITE REFERENCE: King County iMAP (2022) Figure 1.0.7 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 DEVELOPED BASIN MAP 1 SCALE: 1"=50' 1 2 3 4 5 6 11 10 9 8 7 17 16 15 14 13 12 18 19 20 TRACT D TRACT C TRACT B TRACT A ROAD A RO A D B ALLEY Z 11 6 T H A V E S E R O L L I N G H I L L S A V E S E PUG E T D R S E CA M A S C I R S E SE 1 9 T H S T S E 1 9 T H S T ABE R D E E N A V E S E DEVELOPED BASIN MAP DEVELOPED BASIN 2 DEVELOPED BASIN 1 BYPASS BASIN BYPASS BASIN DEVELOPED BASIN 3 EX BUILDING UPSTREAM BASIN BYPASS PER FLOW CONTROL STD (NOTE 4) FLAT 0.13 0.08 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.21 0.13 0.08 0.00 0.00 TOTAL BASIN PER FLOW CONTROL STD:0.13 0.08 0.00 0.00 0.21 BYPASS PER FLOW CONTROL STD (NOTE 4) FLAT 0.02 0.02 0.00 0.00 MOD 0.03 0.02 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.09 0.05 0.04 0.00 0.00 TOTAL BASIN PER FLOW CONTROL STD:0.05 0.04 0.00 0.00 0.09 BASIN 3 BASIN 2 BASIN 1 BASIN 1 TERRAIN IMPERVIOUS (AC) PERVIOUS (AC) LAWN PASTURE FORESTED SITE(NOTE 1) FLAT 2.73 1.58 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:4.31 2.73 1.58 0.00 0.00 MITIGATION TRADE (NOTE 2) FLAT 0.00 0.09 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.09 0.00 0.09 0.00 0.00 UPSTREAM NON-TARGETED AREA (NOTE 3) FLAT 0.00 0.00 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.00 0.00 0.00 0.00 0.00 TOTAL TO FACILITY:4.40 2.73 1.67 0.00 0.00 BYPASS PER FLOW CONTROL STD (NOTE 4) FLAT 0.14 0.00 0.00 0.00 MOD 0.04 0.00 0.00 0.00 STEEP 0.00 0.34 0.00 0.00 SUBTOTAL:0.52 0.18 0.34 0.00 0.00 TOTAL BASIN PER FLOW CONTROL STD:2.91 2.01 0.00 0.00 4.92 DEVELOPED BASIN 2 Figure 1.0.8 SD SD S D S D SD SD S D S D S D S D S D SD SD S D SD S D S D SD SD S D SD SD SD CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS AA A N N N N N N N HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A : C: HA R M O N Y R I D G E A-NNNNNNN PR : B. C . E . J O B N O . 2 2 2 9 8 65 T R E N T ON SK O D A NOT F O R CO N S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 DOWNSTREAM ANALYSIS MAP 1 SCALE: 1"=200' 11 6 T H A V E S E DOWNSTREAM ANALYSIS MAP DEVELOPED BASIN 1 SE 1 6 T H S T E D M O N D S W A Y S E B E A C O N W A Y S E F E R N D A L E A V E S E G L E N N W O O D A V E S E LAKE Y O U N G S W A Y S E H A R R I N G T O N A V E S E S E 1 9 T H S T R O L L I N G H I L L S A V E S E RO L L I N G HI L L S A V E S E S PU G E T D R JO N E S D R S E GR A N T A V E S S 18TH ST S E 1 8 T H P L SE 157TH ST SE 1 5 7 T H P L 12 0 T H AV E S E LAK E Y O U N G S WAY S E RO Y A L H I L L S D R S E ABE R D E E N P L S E 1 DOWNSTREAM ANALYSIS BOUNDARY (14 MILE) DEVELOPED BASIN 2 DEVELOPED BASIN 3 GINGER CREEK THUNDER HILLS CREEK DOWNSTREAM ANALYSIS BOUNDARY (14 MILE) DOWNSTREAM ANALYSIS BOUNDARY (14 MILE) Figure 1.0.9 Section 2.0 22298.001-DRNG 2.0 CONDITIONS AND REQUIREMENTS SUMMARY This section contains the following information: 2.1 Analysis of the Core Requirements and Special Requirements 22298.001-DRNG 2.1 Analysis of the Core Requirements and Special Requirements CORE REQUIREMENTS HOW PROJECT HAS ADDRESSED REQUIREMENT No. 1: Discharge at Natural Location The majority of stormwater runoff from the site sheet flows in a southwest manner and eventually enters the existing conveyance system within the Rolling Hills Village plat to the southwest. From there, runoff flows west for approximately 550 feet and enters the conveyance system on Puget Dr SE and eventually flows into Thunder Hills Creek. A small portion of the east side of the site and the frontage improvement on the north end of 116th Ave SE flows northeast and is tributary to the Ginger Creek sub basin. Another small portion of the frontage improvement on the south end of 116th Ave SE flows to the east and is also tributary to the Ginger Creek sub basin. The two basins, which are tributary to the Ginger Creek sub basin will combine beyond the one-quarter mile threshold downstream of the site and will be considered as two separate drainage basins. In the developed site, runoff tributary to Thunder Hills Creek will be conveyed to the west and discharged into the existing conveyance system on Puget Dr SE, thus maintaining the existing natural discharge location of the site. Runoff from the two basins tributary to the Ginger Creek sub basin as discussed above will combine at a point beyond one-quarter mile downstream of the site and will be considered as two separate drainage basins. Runoff from these two basins will continue to be collected by the existing conveyance system on 116th Ave SE and discharged to the Ginger Creek sub basin. Please refer to the Predeveloped, Developed, and Downstream Basin Maps in this Section 1.0 and the Developed Site Hydrology in Section 4.0 for further detail. No. 2: Off-Site Analysis The off-site analysis has been included within Section 3.0 of this Technical Information Report. No. 3: Flow Control Runoff from all target surfaces in Developed Basin 1 is designed to be collected and detained per Flow Control Duration Standard Matching Forested Site Conditions. Per Section 1.2.3.1B of the 2022 CORSWDM, Basins 2 and 3 do not meet the threshold for flow control requirements. Basins 2 and 3 each cause no more than a 0.15-cfs difference in the 100-year recurrence interval flow frequency. No. 4: Conveyance System The conveyance and backwater analysis is designed per the 2022 CORSWDM for the storm drainage system and is included in Section 5.0 of the Technical Information Report. No. 5: Erosion and Sediment Control Temporary erosion control measures for this project will include stabilized construction entrances, perimeter runoff control, cover practices, sedimentation facilities, and construction sequencing. No. 6: Maintenance and Operations The City will own and maintain the public drainage facility for this project. An Operations and Maintenance Manual is not required for publicly maintained facilities. 22298.001-DRNG No. 7: Bonds and Liability Bonding will be completed by the Applicant. The City’s Bond Quantity Worksheet has been included in Section 9.0 of this report. No. 8: Water Quality The project is proposing a Stormfilter system or approved equal for basic water quality in accordance with the 2022 CORSWDM. No. 9: Onsite BMPs According to the Geotechnical Engineering Study in Section 6.1, the underlying glacial till soil found onsite is not considered feasible for infiltration facilities. Because of this, the following BMPs are infeasible for the lots and roads: Full Infiltration, Limited Infiltration, Bioretention and Permeable Pavement. Full Dispersion cannot be applied as a native vegetated flow path cannot be provided due to site constraints. Finally, roof downspout connections to the permanent storm conveyance system will be done with perforated pipe connections. All pervious surfaces will incorporate soil amendment as detailed in the 2022 CORSWDM. SPECIAL REQUIREMENTS HOW PROJECT HAS ADDRESSED REQUIREMENT No. 1: Other Adopted Area Specific Requirements This special requirement does not apply to this project. No. 2: Floodplain/Floodway Delineation The proposed development is not located within the 100-year floodplain. No. 3: Flood Protection Facilities This project does not rely on an existing flood protection facility nor propose to modify or construct a new flood protection facility, therefore this special requirement does not apply. No. 4: Source Controls This project is a single-family residential project and is not subject to this special requirement. No. 5: Oil Control This site is not classified as a high-use site given the criteria found in the 2022 City of Renton Surface Water Design Manual, therefore no special oil control treatment is necessary. No. 6: Aquifer Protection Area This site is not located within an aquifer protection area. HEX Condition Applicant Response 1 The Applicant shall submit a detailed landscape plan with the civil construction permit application that clearly identifies the utilities and lighting in the planter strips with street tree species selected from the City Approved Street Tree List. The detailed landscape plan shall be reviewed and approved by the Current Planning Project Manager prior to permit issuance. Acknowledged.1 2 The Applicant shall provide a minimum fifteen feet (15’) of perimeter landscaping if any part of the vault is above ground, or if any open detention system is utilized. If required, the landscaping should consist of native large species evergreen trees and complementary understory. If needed, the Applicant shall submit a detailed landscape plan with the civil construction permit application that provides a plant schedule for the stormwater tract screening outside of the fencing area consisting of Douglas Fir, Western Red Cedar, and Western Hemlock with associated shrubs and groundcover as determined by the Current Planning Project Manager. The detailed landscape plan shall be reviewed and approved by the Current Planning Project Manager prior to permit issuance. Acknowledged.The vault is below ground and 2 3 The project shall comply with the 30% tree retention rate as require per RMC 4-4-130.H.1.a. Alternatively, the Applicant shall submit a detailed justification letter documenting conformance with at least one ( 1) of the four ( 4) criteria outlined in RMC 4-4-130.H.1.e. The detailed justification letter shall be submitted to the Current Planning Project Manager for review and approval prior to issuance of the Civil Construction Permit. Acknowledged.3 4 The Applicant shall submit a parking analysis for the existing church and school on proposed Lot 22 that demonstrates compliance with the parking standards in RMC 4-4-140. The analysis shall be submitted to the Current Planning Project Manager for review and approval prior to issuance of the Civil Construction Permit. Acknowledged.4 5 The Applicant shall submit an Inadvertent Discoveries Plan ( IDP) prepared by a qualified professional with the civil construction permit for review and approval by the Current Planning Project manager prior to permit issuance. Acknowledged.5 Harmony Ridge Hearing Examiner's Conditions of Approval for Preliminary Plat, Lot Line Adjustment, and Street Modification Issued December 27, 2024 City of Renton File No. PR21-000076 5/2/2025 1 Hearing Examiner Conditions 6 The Applicant shall submit a narrative describing how the future lots will comply with the lot configuration requirement as outlined in RMC 4-2-115.E.1. The narrative shall be submitted to the Current Planning Project Manager for review and approval prior to issuance of the civil construction permit. Acknowledged.6 7 Lots 1 through 12 shall utilize a public alley for all vehicular access. No curb cuts for Lots 1 through 12 shall be established on 116th Ave SE or future Roads A or B. Acknowledged.7 8 The secondary entrance to future Lot 22, located on future Road A, shall meet one (1) of the following: a) relocate the entrance westward to align with future Alley Z; or b) convert the entrance at the current proposed location to a gated secondary fire emergency access as determined by the Renton Regional Fire Authority ( RRFA); or c) eliminate the entrance if determined to be unnecessary for vehicular circulation and access by the Public Works Plan Reviewer. Acknowledged.8 9 The Applicant shall submit a photometric study and street lighting plan per city standard at the time of construction permit review. Acknowledged.9 10 If the Applicant converts the stormwater vault within Tract A to a stormwater detention pond, it shall be considered a Major Plat Amendment subject to the requirements outlined under RMC 4-7- 080M.2. If utilized, the stormwater vault be located entirely below ground. Engineered construction plans showing the vault entirely below ground shall be submitted to the Public Works Plan Reviewer at the time of construction permit review for review and approval. Acknowledged.10 11 The Applicant shall submit an updated site plan that incorporates a minimum four foot 4’) wide pedestrian pathway in Tract B that connects the street frontage improvements of future Road B to 116th Ave SE. The design for the pedestrian pathway connection shall be submitted to the Current Planning Project Manager for review and approval prior to issuance of the civil construction permit. Acknowledged.11 12 The Applicant shall install all required street frontage improvements on the portion of 116th Ave SE adjacent to proposed Lot 22 ( church site) within two ( 2) years of preliminary plat approval, unless an alternative schedule is approved by the Current Planning Project Manager. Acknowledged.12 13 Street names shall be approved by the City and street name signs shall be installed if required by City staff. Acknowledged.13 5/2/2025 2 Hearing Examiner Conditions 14 Sanitary sewers shall be provided by the developer at no cost to the City and designed in accordance with City standards. Side sewer lines shall be installed eight feet (8') into each lot if sanitary sewer mains are available. Acknowledged.14 15 All utilities designed to serve the subdivision shall be placed underground. Any utilities installed in the parking strip shall be placed in such a manner and depth to permit the planting of trees. Those utilities to be located beneath paved surfaces shall be installed, including all service connections, as approved by the Department. Such installation shall be completed and approved prior to the application of any surface material. Easements may be required for the maintenance and operation of utilities as specified by the Department. Acknowledged.15 16 Any cable TV conduits shall be undergrounded at the same time as other basic utilities are installed to serve each lot. Conduit for service connections shall be laid to each lot line by subdivider as to obviate the necessity for disturbing the street area, including sidewalks, or alley improvements when such service connections are extended to serve any building. The cost of trenching, conduit, pedestals and/or vaults and laterals as well as easements therefore required to bring service to the development shall be borne by the developer and/or landowner. The subdivider shall be responsible only for conduit to serve his development. Conduit ends shall be elbowed to final ground elevation and capped. The cable TV company shall provide maps and specifications to the subdivider and shall inspect the conduit and certify to the City that it is properly installed. Acknowledged.16 5/2/2025 3 Hearing Examiner Conditions Section 3.0 22298.001-DRNG 3.0 OFF-SITE ANALYSIS This section contains the following information: Task 1 – Study Area Definitions and Maps Task 2 – Resource Review Task 3 – Field Inspection 3.1 Conveyance System Nuisance Problems (Type 1) 3.2 Severe Erosion Problems (Type 2) 3.3 Severe Flooding Problems (Type 3) 3.4 Downstream Water Quality Problems Task 4 – Drainage System Description and Problem Descriptions 22298.001-DRNG TASK 1 – STUDY AREA DEFINITION AND MAPS The Harmony Ridge project consists of the development of 20 single-family lots in a 6.24-acre site. The site is located at 15509 116th Ave SE, Renton, WA 98058 in a portion of Section 20, Township 23 North, Range 5 East, Willamette Meridian, in the City of Renton, Washington. The site is adjacent to existing single-family residences to the south and forested land to the west. Runoff tributary to the single-family residences to the south is routed to a closed conveyance system that is downstream of the project site, therefore no upstream runoff is expected from those developments. The general topography of the forested area to the west of the site slopes in a southwest manner, therefore no upstream runoff is expected from this area. This site is also bordered by 116th Ave SE to the east, which conveys runoff to the northeast through an existing conveyance system. The project proposes to collect and detain stormwater which originates onsite. Following detention, stormwater runoff will receive water quality treatment by a Stormfilter System which will be routed to the existing conveyance system on Puget Dr SE. Runoff eventually discharges to Thunder Hills Creek to the southwest of the project site. 22298.001-DRNG TASK 2 – RESOURCE REVIEW • Adopted Basin Plans: The site is tributary to the Thunder Hills Creek sub basin and the Ginger Creek sub basin. There are no known basin plans which impact the proposed project. • Finalized Drainage Studies: There are no finalized drainage studies found within one mile of the downstream of the project site. • Basin Reconnaissance Summary Report: This is not applicable. • Floodplain and Floodway FEMA Maps: The project site is not located in a floodplain area, therefore this is not applicable. • Other Off-Site Analysis Reports: A site investigation was conducted as a Level 1 Off-Site Drainage Analysis. • Critical and Sensitive Area maps: Based on a review of King County iMap, the site is located within a Moderate Coal Mine Hazard Area. According to the Geotechnical Engineering Study included in Section 6.0 of this report, no buffers or setbacks should be applied to the project with respect to the coal mine hazard area and the development is not expected to increase the potential for ground subsidence on the project site. • Sensitive Area maps from the City of Renton were also reviewed. According to the City of Renton Map, the site is not located within a Wellhead Protection Area and is located within an Erosion Hazard Area. The Geotechnical Engineering Study in Section 6.0 of this report states that this site possesses low erosion hazard potential. Typical best management practices and landscaping will mitigate any potential of soil erosion during and after construction. • United States Department of Agriculture Web Soil Survey: Based on the Soils Map (Figure 1.0.4) for this area, the site is located on Alderwood gravelly sandy loam and Alderwood material. This soils type is confirmed by the Geotechnical Engineering Study prepared for the project. • Wetland Inventory Map: The City of Renton Map does not show any wetlands within or adjacent to the project site. • Drainage Complaints along both downstream paths from the site were reviewed on the King County iMap. There were no complaints found within one mile downstream of the project site. In addition, no flooding issues were observed in the area during the downstream analysis. Because of this, the proposed development will not impact on the downstream system. 22298.001-DRNG TASK 3 – FIELD INSPECTION Level 1 Off-Site Drainage Analysis: The field reconnaissance for the Level 1 Off-Site Drainage Analysis was conducted on December 1, 2022. On the day of the visit, conditions were partly cloudy. Several days of rainfall had occurred prior to the site visit with snowfall occurring the day before. As mentioned earlier in this report, runoff from the existing site discharges to two drainage basins, the Thunder Hills Creek sub basin and Ginger Creek sub basin. In the developed condition, most of the stormwater runoff tributary to this development will be collected and routed to a single onsite detention vault which discharges runoff to the Thunder Hills Creek sub basin. Although not disturbed with this project, a UCC building was included in the Predeveloped and Developed Basin 1 areas because rooftop runoff from this building discharges to the onsite forested area and sheet flows to the southwest. This runoff will be collected and routed to the onsite detention vault in the developed condition. Runoff tributary to the northern portion of the frontage improvements required for this development will not be routed to the onsite detention vault. This runoff is tributary to the Ginger Creek sub basin in the existing conditions and will continue to discharge to that basin in the developed conditions. Please refer to the Predeveloped Basin Map (Figure 1.0.3) and the Developed Basin Map (Figure 1.0.8) for further detail regarding the existing and developed drainage basins. Developed Basin 1 (Discharges to the Thunder Hills Creek Sub Basin) The majority of onsite runoff in the existing and developed conditions will flow to the Thunder Hills Creek sub basin. Runoff from the proposed detention vault will be conveyed westward by a new closed conveyance system through the adjacent property before reaching Puget Dr SE. Runoff will flow in a southwest manner along Puget Dr SE through a new closed conveyance system for approximately 420 feet before connecting to the existing roadside conveyance system at the intersection of Puget Dr SE and SE 19th St. A series of photos were taken during the site visit describing the conditions of the existing conveyance system along the downstream flow path. The locations of each of these photos are shown in the Downstream Basin Map (Figure 1.0.9) included in this report. Photo #1 – Looking Southwest Photo #2 – Looking Southwest 22298.001-DRNG Photo #1 shows the existing culvert inlet of the roadside ditch on the east side of Puget Dr SE approximately 30 feet northeast of the Puget Dr SE and SE 19th St intersection. Existing runoff along Puget Dr SE flows southwest along the roadside ditch and enters the culvert inlet at this location. Photo #2 shows the existing catch basin on the northeast side of the intersection. After entering the culvert shown on Photo #1, runoff flows southwest and enters the catch basin shown on Photo #2. The new conveyance system routing runoff along Puget Dr SE will connect to the existing conveyance system by removing the existing storm culvert and installing a new storm pipe that outlets to the catch basin shown in Photo #2. The connection point location is shown on the Developed Basin Map (Figure 1.0.8) and the Downstream Basin Map (Figure 1.0.9). Photo #3 – Looking Southwest Photo #4 – Looking Northeast After entering the catch basin shown in Photo #2, runoff continues to flow southwest across the SE 19th St intersection and outlets to the roadside ditch on the east side of Puget Dr SE shown in Photo #3. From there, runoff continues to flow southwest along the roadside ditch for approximately 330 feet until reaching the end of the ditch at the low point of Puget Dr SE. At the low point location, runoff is conveyed northeast through a culvert and outlets to a roadside ditch on the west side of Puget Dr SE. The location of the culvert inlet is shown in Photo #4. 22298.001-DRNG Photo #5 – Looking Southwest Photo #6 – Looking West Once entering the Puget Dr SE west roadside ditch, runoff flows southwest for approximately 100 feet through a culvert and discharges to another section of the ditch shown in Photo #5. After entering this ditch, runoff continues to flow southwest and enters the manhole shown in Photo #6 through another culvert approximately 40 feet downstream. Photo #7 – Looking West Photo #8 – Looking South 22298.001-DRNG Once entering the manhole shown in Photo #6, runoff begins to flow west across the neighboring property through an existing drainage easement. After approximately 190 feet of flow, runoff outlets to the manhole shown in Photo #7. From there, runoff continues to flow west for approximately 100 feet and outlets into Thunder Hills Creek. Photo #8 above shows the 24-inch outlet culvert into Thunder Hills Creek. Photo #9 – Looking West After entering Thunder Hills Creek, runoff will flow for approximately 130 feet before reaching one- quarter mile downstream. After this point, runoff will continue to flow southwest along the path of Thunder Hills Creek as shown in Photo #9. 22298.001-DRNG Developed Basin 2 (Discharges to the Ginger Creek Sub Basin) A small portion of runoff tributary to a portion of the frontage improvements required along 116th Ave SE will continue to flow north along this road in the developed condition. This area is located on the northeast side of the site and is delineated as Developed Basin 2 in the Developed Basin Map (Figure 1.0.8). A series of photos were taken during the site visit describing the conditions of the existing conveyance system along the downstream flow path. The locations of each of these photos are shown in the Downstream Basin Map (Figure 1.0.9) included in this report. Photo #1 – Looking North Photo #2 – Looking Southeast Photo #1 above shows the existing catch basin located on the west side of 116th Ave SE near the northeast corner of the site. In the developed condition, runoff tributary to the frontage improvements in that area will continue to flow north and enter the catch basin shown in Photo #1. Once entering this catch basin, runoff will continue to flow north for approximately 350 feet before entering the catch basin shown in Photo #2 above at the intersection of 116th Ave SE and Puget Dr SE. 22298.001-DRNG Photo #3 – Looking Northeast Photo #4 – Looking Northeast After entering the catch basin shown in Photo #2, runoff begins to flow southeast for approximately 130 feet before discharging to the manhole shown in Photo #3 within Ginger Creek Park. From there, runoff flows northeast for approximately 90 feet and connects to the existing storm main running southeast through a tee. Runoff begins to flow southeast for approximately 120 feet before entering the manhole on SE 16th St shown in Photo #4. Photo #5 – Looking Northeast Photo #6 – Looking Northeast Once entering the manhole shown in Photo #4, runoff begins to flow northeast along SE 16th St. Runoff continues to flow in this direction for approximately 320 feet before discharging into the 22298.001-DRNG manhole shown in Photo #5. After another 310 feet of flow path to the northeast runoff reaches one- quarter downstream just before discharging into the manhole shown in Photo #6. Developed Basin 3 (Discharges to the Ginger Creek Sub Basin) Another small portion of runoff tributary to a portion of the frontage improvements required along the south end of 116th Ave will flow to the south towards the intersection of 116th Ave SE and SE 157th St. From there, the flow will continue east along SE 157th St and SE 157th Pl where it reaches the point one-quarter mile downstream of the site. The flow will continue to flow to the north through Tiffany Park and a drainage easement behind Glennwood Ave SE before it combines with the downstream flow path of Developed Basin 2 at the intersection of SE16th St and Lake Youngs Way SE. Since the two basins combine at a point beyond one-quarter mile downstream of the site, these two basins will be considered as separate basins. 22298.001-DRNG 3.1 Conveyance System Nuisance Problems (Type 1) Conveyance system nuisance problems are minor but not chronic flooding or erosion problems that result from the overflow of a constructed conveyance system that is substandard or has become too small as a result of upstream development. Such problems warrant additional attention because of their chronic nature and because they result from the failure of a conveyance system to provide a minimum acceptable level of protection. There were no conveyance system nuisance problems observed during the December 1, 2022, site visit. 3.2 Severe Erosion Problems (Type 2) Severe erosion problems can be caused by conveyance system overflows or the concentration of runoff into erosion-sensitive open drainage features. Severe erosion problems warrant additional attention because they pose a significant threat either to health and safety, or to public or private property. Runoff within one-quarter mile downstream of the project site is not discharged into any erosion-sensitive open drainage features. In addition, there were no conveyance system overflows observed during the December 1, 2022, site visit. Because of this, no future erosion problems should occur downstream. 3.3 Severe Flooding Problems (Type 3) Severe flooding problems can be caused by conveyance system overflows or the elevated water surfaces of ponds, lakes, wetlands, or closed depressions. Severe flooding problems are defined as follows: • Flooding of the finished area of a habitable building for runoff events less than or equal to the 100-year event. Examples include flooding of finished floors of homes and commercial or industrial buildings. Flooding in electrical/heating systems and components in the crawlspace or garage of a home. Such problems are referred to as "severe building flooding problems." • Flooding over all lanes of a roadway or severely impacting a sole access driveway for runoff events less than or equal to the 100-year event. Such problems are referred to as "severe roadway flooding problems." Based on a review of the FEMA Map (Section 1.0) the proposed site is not located in any floodplain areas therefore no severe flooding problems are expected. 3.4 Downstream Water Quality Problems After reviewing the Washington State Department of Ecology Water Quality Atlas, there are no Category 5, 4 or 2 Waterbodies located within one-quarter mile downstream of the project site therefore no water quality problems are expected from this development. 22298.001-DRNG TASK 4 – DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS UPSTREAM DRAINAGE ANALYSIS The site is adjacent to existing single-family residences to the south and forested land to the west. Runoff tributary to the single-family residences to the south is routed to a closed conveyance system that is downstream of the project site, therefore no upstream runoff is expected from those developments. The general topography of the forested area to the west of the site slopes in a southwest manner, therefore no upstream runoff is expected from this area. This site is also bordered by 116th Ave SE to the east, which conveys runoff to the northeast through an existing conveyance system. Section 4.0 22298.001-DRNG 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN This section contains the following information: 4.1 Existing Site Hydrology 4.2 Developed Site Hydrology 4.3 Performance Standards 4.4 Flow Control System 4.5 Water Quality System 22298.001-DRNG 4.1 Existing Site Hydrology The existing conditions of the project site consist of four existing buildings and a parking lot gaining access from 116th Ave SE along the east boundary line. Aside from these existing developed areas, the site mostly consists of undisturbed forested area. There are no natural drainage courses of any kind on the property. Elevations range from 465 to 420 feet across the site with slopes ranging from approximately 2 to 25%. The Geotechnical Engineering Study prepared by Earth Solutions NW, LLC identified the underlying native soil as glacial till deposits between the depths of 0.5 to 14 feet. These soils are considered infeasible for infiltration facilities per the Geotechnical Engineering Study included in Section 6.1 of this report. The majority of stormwater runoff from the existing site and the area of the proposed utility access road (4.67 acres) flows in a southwest manner and enters the existing conveyance system within the Rolling Hills Village Plat to the southwest. This area was delineated as Predeveloped Basin 1 in the Predeveloped Basin Map included in Section 1.0 of this report. Although not disturbed with this development, an existing UCC building was included in the Predeveloped Basin 1 as an upstream basin (0.09 Ac) because rooftop runoff from this building discharges to the forested area onsite and sheet flows to the southwest. Once entering the existing conveyance system within the Rolling Hills Village Plat, runoff flows west for approximately 550 feet before entering the conveyance system on Puget Dr SE. Runoff continues to flow southwest and eventually discharges to Thunder Hills Creek. Predeveloped Basin 1 Impervious Pervious Total Area 0.00 Ac 4.67 Ac(1) 4.67 Ac Notes: 1. Modeled as Forested Flat slope Existing Building Upstream Basin Impervious Pervious Total Area 0.00 Ac 0.09 Ac(1) 0.09 Ac Notes: 1. Modeled as Forested Flat slope 22298.001-DRNG A small portion on the east end of the site and the north end of 116th Ave SE flows towards the north on 116th Ave SE and is tributary to the Ginger Creek sub basin to the northeast. This area is approximately 0.45 acres in size and is delineated as Predeveloped Basin 2 in the Predeveloped Basin Map in Section 1.0 of this report. Please refer to this map for further detail on the predeveloped basin areas. Per the requirement of the 2022 CORSWDM, All predeveloped basin areas were modeled as forested till soil. The majority of the area of the three UCC buildings and the associated parking lot will be undisturbed and were not included in the Predeveloped Basin 2 drainage basin area. Predeveloped Basin 2 Impervious Pervious Total Area 0.00 Ac 0.45 Ac(1) 0.45 Ac Notes: 1. Modeled as Forested Flat slope Predeveloped Basin 3 is the area associated with the frontage improvements on the south end of 116th Ave SE. The runoff tributary to this area will flow south towards the intersection of 116th Ave SE and SE 157th St and also is tributary to the Ginger Creek sub basin to the northeast. This area is approximately 0.09 acres in size and is delineated as Predeveloped Basin 3 in the Predeveloped Basin Map in Section 1.0 of this report Predeveloped Basin 3 Impervious Pervious Total Area 0.00 Ac 0.09 Ac(1) 0.09 Ac Notes: 1. Modeled as Forested Flat slope 22298.001-DRNG 4.2 Developed Site Hydrology When completed, the Harmony Ridge project will create 20 new single-family residences. The project development will consist of access roads, planter strips, sidewalks, driveways, utilities and a detention vault. As shown in the Developed Basin Map, the site will consist of three basins in the developed condition: Developed Basins 1, 2 and 3. Developed Basin 1 Developed Basin 1 is tributary to the Thunder Hills Creek sub basin and consists of all onsite impervious and pervious areas including access roads, sidewalks, driveways, lot areas and lawn areas. This basin will also include the area of the proposed utility access road connecting Tract A to Puget Dr SE that will be bypassed. A conveyance system consisting of catch basins and storm pipes will be constructed to collect and route stormwater runoff from the target surfaces to the onsite detention vault. This conveyance system will also connect to the existing outlet of the UCC church building within Tract D and route its rooftop runoff to the onsite detention vault. This is done to maintain the existing discharge location of rooftop runoff tributary to the building. As previously stated, infiltration is not feasible for this site due to the presence of glacial till soils. Because of this, all lots will provide perforated stub-out connections that will be tightlined to the proposed stormwater conveyance system. A breakdown of the impervious and pervious areas in the Developed Basin is shown in the table below. A more detailed breakdown is shown in the Developed Basin Map included as Figure 1.0.8 in this report. Developed Basin 1 Impervious Pervious Total Area 2.91 Ac(1,4) 2.01 Ac(2,3,4) 4.92 Ac Notes: 1. R/W = 0.96 Ac Lot Area @ 65% Impervious (4,000 SF Max) = 1.63 Ac Tract A = 0.03 Ac Alley Z = 0.11 Ac 2. Modeled as till grass Flat = 1.58 Ac 3. Mitigation Trade (Upstream Building) = 0.09 Ac 4. Bypass Impervious = 0.18 Ac Pervious = 0.34 Ac Mitigation Trade: The rooftop runoff tributary to the existing UCC building will be collected into the detention vault and count towards a mitigation trade for a portion of the bypassed areas unable to be conveyed to the drainage facility. 22298.001-DRNG Developed Basin 2 As shown in the Developed Basin Map (Figure 1.0.8), a portion of the runoff tributary to the frontage improvements required along the north end of 116th Ave SE (0.21 acres) will not be routed to the onsite vault because it is tributary to the Ginger Creek sub basin. It should be noted that although the three UCC buildings and parking lot in this area of the site also discharged to the Ginger Creek sub basin, they were not included in the Developed Basin 2 area because they will not be disturbed with this development. Please refer to Sections 4.4 and 4.5 for further detail on the flow control and water quality calculations for this basin. Developed Basin 2 Impervious Pervious Total Area 0.13 Ac(1) 0.08 Ac(2) 0.21 Ac Notes: 1. R/W = 0.13 Ac 2. Modeled as till grass Flat = 0.08 Ac Developed Basin 3 A portion of runoff tributary to the frontage improvements required on the south end of 116th Ave SE (0.09 acres) will not be routed to the onsite vault because it is tributary to the Ginger Creek sub basin. Please refer to Sections 4.4 and 4.5 for further detail on the flow control and water quality calculations for this basin. Developed Basin 3 Impervious Pervious Total Area 0.05 Ac(1) 0.04 Ac(2) 0.09 Ac Notes: 1. R/W = 0.05 Ac 2. Modeled as till grass Flat = 0.04 Ac 22298.001-DRNG 4.3 Performance Standards This project is subject to Core Requirement #9 of the 2022 CORSWDM requiring the application of onsite BMPs to mitigate stormwater runoff. A feasibility table has been provided below discussing the evaluation of each BMP found in the 2022 CORSWDM. In addition, the 2022 CORSWDM states that the assumed impervious coverage for each lot shall be 4,000 square feet per lot, or the maximum impervious coverage permitted per Table 3.2.2.C, whichever is less. Lot 17, the largest lot size proposed for this project has an area of 6,405 square feet which results in a maximum impervious surface of 4,163 square feet. This lot is the only lot where the 65% impervious surface area exceeds the 4,000 square feet threshold. All lots excluding Lot 17 will use the maximum lot impervious surface coverage of 65% to size the onsite detention vault. The WWHM program was used to size the detention vault for this project. The flow control requirement for this project is the Flow Control Duration Standard Matching Forested Site Conditions. Please refer to the WWHM calculations located in Section 4.4 of this report for further detail. This project is also required to provide Basic Water Quality and will do so via a Stormfilter System. Please refer to Section 4.5 for further detail. Core Requirement #9 – Onsite BMP Evaluation Full Dispersion Not feasible for this site due to lot constrains Full infiltration Not feasible for this site due to soil condition unsuitable for infiltration per the results of the geotechnical report, which is included in Section 6.0 of this TIR. Limited Infiltration Not feasible for this site due to soil condition unsuitable for infiltration per the results of the geotechnical report, which is included in Section 6.0 of this TIR. Basic Dispersion Basic dispersion will be utilized on a lot-by-lot basis. Further evaluation will be done during the building permit submittal. Farmland Dispersion Not applicable. Bioretention Not feasible for this site due to soil condition unsuitable for infiltration per the results of the geotechnical report, which is included in Section 6.0 of this TIR. Permeable Pavement Not feasible for this site due to soil condition unsuitable for infiltration per the results of the geotechnical report, which is included in Section 6.0 of this TIR. Rainwater Harvesting Feasible but impractical, evaluated on an individual lot basis at developer’s discretion. Reduced Impervious Surface Credit This project has set a maximum impervious surface of 4,000 SF per lot. A restrictive covenant will be provided on the final plat. Individual lot BMP’s will be evaluated at building permit stage and may result in a footprint less than 4,000 SF if other BMP methods cannot be utilized. Native Growth Retention Credit Not feasible due to site constrains. Perforated Pipe Connection All lots will provide perforated stub out connections when tight lined to the proposed stormwater conveyance system. Rain Gardens Not feasible for this site due to limitation caused by landscape requirements and utility placement. Soil Amendment The soil amendment BMP will be applied to all disturbed pervious surfaces. Tree Retention Credit Not feasible due to site constrains. Vegetated Roofs All roofs are pitch roofs and are unsuitable for this BMP implication. 22298.001-DRNG 4.4 Flow Control System Developed Basin 1 The onsite detention vault was sized per the Flow Control Duration Standard Matching Forested Site Conditions based on the 2022 CORSWDM. This standard requires that discharges are designed to match developed discharge durations to predeveloped durations (historical) for the range of 50 percent of the 2-year peak flow up to the 50-year peak flow. This standard also requires that the 2- year and 10-year predeveloped (historical) peak flows be matched in the developed condition. Please refer to the WWHM calculations provided in this section for further detail. The required and provided volumes for the detention vault are as follows: Tract A - Detention Vault Volume Required Provided 67,400 CF 69,850 CF The control structure and riser within the Detention Vault have been sized to overtop the 100-year unmitigated release rate of 2.54 CFS should the control structure's orifices become plugged or fail. Peak design flows for the predeveloped, developed and mitigated developed site area as follows: Detention Vault - Design Flow Rates (CFS) Peak Flows Predeveloped Unmitigated Developed Mitigated Developed 2-year 0.14 1.15 0.15 10-year 0.27 1.73 0.26 100-year 0.37 2.54 0.41 Developed Basin 2 As noted earlier, there are approximately 0.21 acres of runoff from the frontage improvements on 116th Ave SE to the north of the site entrance that will not be routed to the onsite detention vault. This runoff is tributary to the Ginger Creek sub basin and has a separate threshold discharge area from Developed Basin 1. According to Section 1.2.3.1B of the 2022 CORSWDM, the facility requirement in Flow Control Duration Standard Matching Forested Site Conditions is waived for any threshold discharge area in which there is no more than a 0.15 cfs difference in the sum of developed 100-year peak flows for those target surfaces and the sum of historical site conditions 100-year peak flows for the same surfaces. As shown in Figure 4.4.2, the difference in the 100-year peak flows between the historical site conditions and developed site conditions does not exceed 0.15 cfs, therefore a flow control facility is not required for this basin. Developed Basin 2 - Design Flow Rates (CFS) Peak Flows Predeveloped Developed 100-year 0.035 0.122 22298.001-DRNG Developed Basin 3 There is approximately 0.09 acres of runoff from the frontage improvements on 116th Ave SE to the south of the site entrance that will not be routed to the onsite detention vault. Similar to Developed Basin 2, this basin that is tributary to the Ginger Creek sub basin does not meet the flow control requirements due to there not being more than a 0.15 cfs difference in the sum of the developed 100- year peak flow. Therefore, a flow control facility is not required for Developed Basin 3. Developed Basin 3 - Design Flow Rates (CFS) Peak Flows Predeveloped Developed 100-year 0.01 0.05 WWHM2012 PROJECT REPORT Figure 4.4.1 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 2 General Model Information WWHM2012 Project Name:22298-WWHM-Vault-15.8 Site Name:Harmony Ridge Site Address: City: Report Date:8/1/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 4.67 Pervious Total 4.67 Impervious Land Use acre Impervious Total 0 Basin Total 4.67 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 4 Ex Builing - Upstream Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.09 Pervious Total 0.09 Impervious Land Use acre Impervious Total 0 Basin Total 0.09 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 5 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.58 Pervious Total 1.58 Impervious Land Use acre ROADS FLAT 2.73 Impervious Total 2.73 Basin Total 4.31 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 6 Ex Builing - Upstream Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.09 Pervious Total 0.09 Impervious Land Use acre Impervious Total 0 Basin Total 0.09 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 7 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Steep 0.34 Pervious Total 0.34 Impervious Land Use acre ROADS FLAT 0.14 ROADS MOD 0.04 Impervious Total 0.18 Basin Total 0.52 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 8 Routing Elements Predeveloped Routing 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 9 Mitigated Routing Vault 1 Width:65.3 ft. Length:65.3 ft. Depth:16.8 ft. Discharge Structure Riser Height:15.8 ft. Riser Diameter:18 in. Orifice 1 Diameter:0.750 in.Elevation:0 ft. Orifice 2 Diameter:1.380 in.Elevation:11 ft. Orifice 3 Diameter:1.190 in.Elevation:13 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.097 0.000 0.000 0.000 0.1867 0.097 0.018 0.006 0.000 0.3733 0.097 0.036 0.009 0.000 0.5600 0.097 0.054 0.011 0.000 0.7467 0.097 0.073 0.013 0.000 0.9333 0.097 0.091 0.014 0.000 1.1200 0.097 0.109 0.016 0.000 1.3067 0.097 0.127 0.017 0.000 1.4933 0.097 0.146 0.018 0.000 1.6800 0.097 0.164 0.019 0.000 1.8667 0.097 0.182 0.020 0.000 2.0533 0.097 0.201 0.021 0.000 2.2400 0.097 0.219 0.022 0.000 2.4267 0.097 0.237 0.023 0.000 2.6133 0.097 0.255 0.024 0.000 2.8000 0.097 0.274 0.025 0.000 2.9867 0.097 0.292 0.026 0.000 3.1733 0.097 0.310 0.027 0.000 3.3600 0.097 0.328 0.028 0.000 3.5467 0.097 0.347 0.028 0.000 3.7333 0.097 0.365 0.029 0.000 3.9200 0.097 0.383 0.030 0.000 4.1067 0.097 0.402 0.030 0.000 4.2933 0.097 0.420 0.031 0.000 4.4800 0.097 0.438 0.032 0.000 4.6667 0.097 0.456 0.033 0.000 4.8533 0.097 0.475 0.033 0.000 5.0400 0.097 0.493 0.034 0.000 5.2267 0.097 0.511 0.034 0.000 5.4133 0.097 0.529 0.035 0.000 5.6000 0.097 0.548 0.036 0.000 5.7867 0.097 0.566 0.036 0.000 5.9733 0.097 0.584 0.037 0.000 6.1600 0.097 0.603 0.037 0.000 6.3467 0.097 0.621 0.038 0.000 6.5333 0.097 0.639 0.039 0.000 6.7200 0.097 0.657 0.039 0.000 6.9067 0.097 0.676 0.040 0.000 Volume Required = 67,400 CF 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 10 7.0933 0.097 0.694 0.040 0.000 7.2800 0.097 0.712 0.041 0.000 7.4667 0.097 0.730 0.041 0.000 7.6533 0.097 0.749 0.042 0.000 7.8400 0.097 0.767 0.042 0.000 8.0267 0.097 0.785 0.043 0.000 8.2133 0.097 0.804 0.043 0.000 8.4000 0.097 0.822 0.044 0.000 8.5867 0.097 0.840 0.044 0.000 8.7733 0.097 0.858 0.045 0.000 8.9600 0.097 0.877 0.045 0.000 9.1467 0.097 0.895 0.046 0.000 9.3333 0.097 0.913 0.046 0.000 9.5200 0.097 0.931 0.047 0.000 9.7067 0.097 0.950 0.047 0.000 9.8933 0.097 0.968 0.048 0.000 10.080 0.097 0.986 0.048 0.000 10.267 0.097 1.005 0.048 0.000 10.453 0.097 1.023 0.049 0.000 10.640 0.097 1.041 0.049 0.000 10.827 0.097 1.059 0.050 0.000 11.013 0.097 1.078 0.056 0.000 11.200 0.097 1.096 0.074 0.000 11.387 0.097 1.114 0.083 0.000 11.573 0.097 1.132 0.091 0.000 11.760 0.097 1.151 0.097 0.000 11.947 0.097 1.169 0.103 0.000 12.133 0.097 1.187 0.108 0.000 12.320 0.097 1.206 0.113 0.000 12.507 0.097 1.224 0.117 0.000 12.693 0.097 1.242 0.121 0.000 12.880 0.097 1.260 0.125 0.000 13.067 0.097 1.279 0.139 0.000 13.253 0.097 1.297 0.152 0.000 13.440 0.097 1.315 0.162 0.000 13.627 0.097 1.333 0.170 0.000 13.813 0.097 1.352 0.178 0.000 14.000 0.097 1.370 0.185 0.000 14.187 0.097 1.388 0.191 0.000 14.373 0.097 1.407 0.197 0.000 14.560 0.097 1.425 0.203 0.000 14.747 0.097 1.443 0.209 0.000 14.933 0.097 1.461 0.214 0.000 15.120 0.097 1.480 0.220 0.000 15.307 0.097 1.498 0.225 0.000 15.493 0.097 1.516 0.230 0.000 15.680 0.097 1.534 0.235 0.000 15.867 0.097 1.553 0.513 0.000 16.053 0.097 1.571 2.219 0.000 16.240 0.097 1.589 4.307 0.000 16.427 0.097 1.608 5.809 0.000 16.613 0.097 1.626 6.648 0.000 16.800 0.097 1.644 7.348 0.000 16.987 0.096 1.559 7.985 0.000 22298-WWHM-Vault-15.8 8/1/2025 10:00:01 AM Page 11 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.76 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.01 Total Impervious Area:2.91 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.139948 5 year 0.219794 10 year 0.265044 25 year 0.312982 50 year 0.342647 100 year 0.367878 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.151974 5 year 0.212373 10 year 0.255784 25 year 0.31457 50 year 0.361259 100 year 0.410465 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.137 0.202 1950 0.171 0.194 1951 0.308 0.325 1952 0.097 0.094 1953 0.079 0.109 1954 0.121 0.127 1955 0.192 0.126 1956 0.153 0.189 1957 0.124 0.153 1958 0.139 0.107 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 12 1959 0.119 0.098 1960 0.208 0.191 1961 0.118 0.157 1962 0.073 0.088 1963 0.100 0.138 1964 0.132 0.128 1965 0.095 0.154 1966 0.091 0.114 1967 0.190 0.196 1968 0.119 0.172 1969 0.116 0.145 1970 0.096 0.130 1971 0.102 0.150 1972 0.229 0.264 1973 0.104 0.135 1974 0.113 0.155 1975 0.153 0.162 1976 0.111 0.127 1977 0.013 0.099 1978 0.097 0.121 1979 0.059 0.132 1980 0.217 0.233 1981 0.087 0.139 1982 0.167 0.249 1983 0.150 0.130 1984 0.093 0.098 1985 0.055 0.127 1986 0.243 0.143 1987 0.215 0.180 1988 0.085 0.090 1989 0.055 0.087 1990 0.449 0.322 1991 0.270 0.279 1992 0.104 0.113 1993 0.109 0.081 1994 0.036 0.072 1995 0.156 0.144 1996 0.328 0.313 1997 0.274 0.282 1998 0.062 0.129 1999 0.257 0.266 2000 0.108 0.150 2001 0.019 0.120 2002 0.119 0.192 2003 0.151 0.174 2004 0.196 0.261 2005 0.141 0.130 2006 0.166 0.175 2007 0.333 0.360 2008 0.430 0.289 2009 0.211 0.174 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.4486 0.3605 2 0.4296 0.3250 3 0.3330 0.3215 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 13 4 0.3279 0.3125 5 0.3082 0.2888 6 0.2741 0.2822 7 0.2701 0.2790 8 0.2571 0.2656 9 0.2426 0.2636 10 0.2295 0.2610 11 0.2175 0.2495 12 0.2146 0.2330 13 0.2109 0.2024 14 0.2084 0.1963 15 0.1959 0.1944 16 0.1923 0.1915 17 0.1903 0.1914 18 0.1714 0.1888 19 0.1672 0.1801 20 0.1657 0.1745 21 0.1556 0.1744 22 0.1533 0.1736 23 0.1530 0.1721 24 0.1513 0.1617 25 0.1499 0.1567 26 0.1405 0.1547 27 0.1391 0.1545 28 0.1375 0.1529 29 0.1322 0.1505 30 0.1235 0.1496 31 0.1206 0.1447 32 0.1194 0.1437 33 0.1187 0.1429 34 0.1186 0.1386 35 0.1176 0.1378 36 0.1161 0.1351 37 0.1131 0.1324 38 0.1108 0.1303 39 0.1085 0.1297 40 0.1082 0.1296 41 0.1042 0.1293 42 0.1042 0.1281 43 0.1024 0.1272 44 0.1004 0.1270 45 0.0972 0.1268 46 0.0971 0.1258 47 0.0958 0.1211 48 0.0946 0.1202 49 0.0925 0.1137 50 0.0910 0.1131 51 0.0869 0.1093 52 0.0847 0.1073 53 0.0785 0.0986 54 0.0731 0.0983 55 0.0620 0.0980 56 0.0588 0.0940 57 0.0552 0.0905 58 0.0549 0.0882 59 0.0365 0.0873 60 0.0194 0.0809 61 0.0132 0.0723 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 14 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 15 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0700 17552 14934 85 Pass 0.0727 16164 13650 84 Pass 0.0755 14964 12585 84 Pass 0.0782 13851 11693 84 Pass 0.0810 12810 10940 85 Pass 0.0837 11809 10217 86 Pass 0.0865 10900 9537 87 Pass 0.0893 10119 8932 88 Pass 0.0920 9383 8339 88 Pass 0.0948 8729 7824 89 Pass 0.0975 8145 7302 89 Pass 0.1003 7608 6819 89 Pass 0.1030 7063 6363 90 Pass 0.1058 6596 5935 89 Pass 0.1085 6149 5542 90 Pass 0.1113 5788 5163 89 Pass 0.1140 5437 4778 87 Pass 0.1168 5110 4395 86 Pass 0.1196 4810 4032 83 Pass 0.1223 4524 3720 82 Pass 0.1251 4256 3435 80 Pass 0.1278 4017 3146 78 Pass 0.1306 3788 2905 76 Pass 0.1333 3548 2699 76 Pass 0.1361 3341 2530 75 Pass 0.1388 3138 2391 76 Pass 0.1416 2954 2257 76 Pass 0.1443 2787 2145 76 Pass 0.1471 2603 2058 79 Pass 0.1498 2449 1980 80 Pass 0.1526 2304 1901 82 Pass 0.1554 2162 1825 84 Pass 0.1581 2025 1743 86 Pass 0.1609 1901 1691 88 Pass 0.1636 1790 1626 90 Pass 0.1664 1690 1565 92 Pass 0.1691 1586 1500 94 Pass 0.1719 1483 1436 96 Pass 0.1746 1381 1362 98 Pass 0.1774 1293 1299 100 Pass 0.1801 1221 1246 102 Pass 0.1829 1155 1186 102 Pass 0.1857 1098 1114 101 Pass 0.1884 1048 1050 100 Pass 0.1912 997 988 99 Pass 0.1939 930 924 99 Pass 0.1967 884 860 97 Pass 0.1994 837 805 96 Pass 0.2022 789 756 95 Pass 0.2049 743 707 95 Pass 0.2077 713 641 89 Pass 0.2104 668 576 86 Pass 0.2132 633 535 84 Pass 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 16 0.2160 596 490 82 Pass 0.2187 565 449 79 Pass 0.2215 539 415 76 Pass 0.2242 496 392 79 Pass 0.2270 473 366 77 Pass 0.2297 434 337 77 Pass 0.2325 401 311 77 Pass 0.2352 366 290 79 Pass 0.2380 348 268 77 Pass 0.2407 323 248 76 Pass 0.2435 296 221 74 Pass 0.2462 272 201 73 Pass 0.2490 256 178 69 Pass 0.2518 235 161 68 Pass 0.2545 217 146 67 Pass 0.2573 197 130 65 Pass 0.2600 180 115 63 Pass 0.2628 158 102 64 Pass 0.2655 145 94 64 Pass 0.2683 129 83 64 Pass 0.2710 119 77 64 Pass 0.2738 109 62 56 Pass 0.2765 97 55 56 Pass 0.2793 91 48 52 Pass 0.2821 82 45 54 Pass 0.2848 76 38 50 Pass 0.2876 69 32 46 Pass 0.2903 61 30 49 Pass 0.2931 54 25 46 Pass 0.2958 48 22 45 Pass 0.2986 41 21 51 Pass 0.3013 38 19 50 Pass 0.3041 33 14 42 Pass 0.3068 27 14 51 Pass 0.3096 22 13 59 Pass 0.3124 21 12 57 Pass 0.3151 20 8 40 Pass 0.3179 19 6 31 Pass 0.3206 17 5 29 Pass 0.3234 14 3 21 Pass 0.3261 12 2 16 Pass 0.3289 9 2 22 Pass 0.3316 4 2 50 Pass 0.3344 3 2 66 Pass 0.3371 3 1 33 Pass 0.3399 3 1 33 Pass 0.3426 3 1 33 Pass 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 17 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. 22298-WWHM-Vault-15.8 8/1/2025 10:00:25 AM Page 18 LID Report 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 19 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. 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 20 Appendix Predeveloped Schematic 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 21 Mitigated Schematic 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 22 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 22298-WWHM-Vault-15.8.wdm MESSU 25 Pre22298-WWHM-Vault-15.8.MES 27 Pre22298-WWHM-Vault-15.8.L61 28 Pre22298-WWHM-Vault-15.8.L62 30 POC22298-WWHM-Vault-15.81.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 23 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 24 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 10 4.67 COPY 501 12 PERLND 10 4.67 COPY 501 13 Ex Builing - Upstream*** PERLND 10 0.09 COPY 501 12 PERLND 10 0.09 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 25 <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 END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 26 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 22298-WWHM-Vault-15.8.wdm MESSU 25 Mit22298-WWHM-Vault-15.8.MES 27 Mit22298-WWHM-Vault-15.8.L61 28 Mit22298-WWHM-Vault-15.8.L62 30 POC22298-WWHM-Vault-15.81.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 PERLND 10 PERLND 18 IMPLND 2 RCHRES 1 COPY 1 COPY 501 COPY 601 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Vault 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 601 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 10 C, Forest, Flat 1 1 1 1 27 0 18 C, Lawn, Steep 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 27 # - # 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 10 0 0 1 0 0 0 0 0 0 0 0 0 18 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 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 18 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 10 0 0 0 0 0 0 0 0 0 0 0 18 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 10 0 4.5 0.08 400 0.05 0.5 0.996 18 0 4.5 0.03 400 0.15 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 10 0 0 2 2 0 0 0 18 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 10 0.2 0.5 0.35 6 0.5 0.7 18 0.1 0.15 0.25 6 0.3 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 10 0 0 0 0 2.5 1 0 18 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 2 ROADS/MOD 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 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 28 2 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 2 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 2 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 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 2 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 1.58 RCHRES 1 2 PERLND 16 1.58 RCHRES 1 3 IMPLND 1 2.73 RCHRES 1 5 Ex Builing - Upstream*** PERLND 10 0.09 RCHRES 1 2 PERLND 10 0.09 RCHRES 1 3 Bypass*** PERLND 18 0.34 COPY 501 12 PERLND 18 0.34 COPY 601 12 PERLND 18 0.34 COPY 501 13 PERLND 18 0.34 COPY 601 13 IMPLND 1 0.14 COPY 501 15 IMPLND 1 0.14 COPY 601 15 IMPLND 2 0.04 COPY 501 15 IMPLND 2 0.04 COPY 601 15 ******Routing****** PERLND 16 1.58 COPY 1 12 IMPLND 1 2.73 COPY 1 15 PERLND 16 1.58 COPY 1 13 PERLND 10 0.09 COPY 1 12 PERLND 10 0.09 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 29 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Vault 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 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 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 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 0.097890 0.000000 0.000000 0.186667 0.097890 0.018273 0.006595 0.373333 0.097890 0.036546 0.009327 0.560000 0.097890 0.054818 0.011423 0.746667 0.097890 0.073091 0.013190 0.933333 0.097890 0.091364 0.014747 1.120000 0.097890 0.109637 0.016154 1.306667 0.097890 0.127910 0.017449 1.493333 0.097890 0.146182 0.018653 1.680000 0.097890 0.164455 0.019785 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 30 1.866667 0.097890 0.182728 0.020855 2.053333 0.097890 0.201001 0.021873 2.240000 0.097890 0.219274 0.022846 2.426667 0.097890 0.237546 0.023779 2.613333 0.097890 0.255819 0.024676 2.800000 0.097890 0.274092 0.025542 2.986667 0.097890 0.292365 0.026380 3.173333 0.097890 0.310638 0.027192 3.360000 0.097890 0.328911 0.027980 3.546667 0.097890 0.347183 0.028747 3.733333 0.097890 0.365456 0.029494 3.920000 0.097890 0.383729 0.030222 4.106667 0.097890 0.402002 0.030933 4.293333 0.097890 0.420275 0.031628 4.480000 0.097890 0.438547 0.032309 4.666667 0.097890 0.456820 0.032975 4.853333 0.097890 0.475093 0.033628 5.040000 0.097890 0.493366 0.034269 5.226667 0.097890 0.511639 0.034897 5.413333 0.097890 0.529911 0.035515 5.600000 0.097890 0.548184 0.036122 5.786667 0.097890 0.566457 0.036719 5.973333 0.097890 0.584730 0.037307 6.160000 0.097890 0.603003 0.037885 6.346667 0.097890 0.621275 0.038455 6.533333 0.097890 0.639548 0.039017 6.720000 0.097890 0.657821 0.039570 6.906667 0.097890 0.676094 0.040116 7.093333 0.097890 0.694367 0.040654 7.280000 0.097890 0.712639 0.041186 7.466667 0.097890 0.730912 0.041710 7.653333 0.097890 0.749185 0.042229 7.840000 0.097890 0.767458 0.042740 8.026667 0.097890 0.785731 0.043246 8.213333 0.097890 0.804004 0.043746 8.400000 0.097890 0.822276 0.044241 8.586667 0.097890 0.840549 0.044729 8.773333 0.097890 0.858822 0.045213 8.960000 0.097890 0.877095 0.045691 9.146667 0.097890 0.895368 0.046165 9.333333 0.097890 0.913640 0.046634 9.520000 0.097890 0.931913 0.047098 9.706667 0.097890 0.950186 0.047557 9.893333 0.097890 0.968459 0.048012 10.08000 0.097890 0.986732 0.048463 10.26667 0.097890 1.005004 0.048910 10.45333 0.097890 1.023277 0.049352 10.64000 0.097890 1.041550 0.049791 10.82667 0.097890 1.059823 0.050226 11.01333 0.097890 1.078096 0.056625 11.20000 0.097890 1.096368 0.074196 11.38667 0.097890 1.114641 0.083644 11.57333 0.097890 1.132914 0.091060 11.76000 0.097890 1.151187 0.097399 11.94667 0.097890 1.169460 0.103042 12.13333 0.097890 1.187732 0.108187 12.32000 0.097890 1.206005 0.112953 12.50667 0.097890 1.224278 0.117417 12.69333 0.097890 1.242551 0.121633 12.88000 0.097890 1.260824 0.125641 13.06667 0.097890 1.279096 0.139394 13.25333 0.097890 1.297369 0.152489 13.44000 0.097890 1.315642 0.162177 13.62667 0.097890 1.333915 0.170525 13.81333 0.097890 1.352188 0.178071 14.00000 0.097890 1.370461 0.185054 14.18667 0.097890 1.388733 0.191610 14.37333 0.097890 1.407006 0.197822 14.56000 0.097890 1.425279 0.203751 14.74667 0.097890 1.443552 0.209437 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 31 14.93333 0.097890 1.461825 0.214914 15.12000 0.097890 1.480097 0.220205 15.30667 0.097890 1.498370 0.225332 15.49333 0.097890 1.516643 0.230310 15.68000 0.097890 1.534916 0.235154 15.86667 0.097890 1.553189 0.513570 16.05333 0.097890 1.571461 2.219757 16.24000 0.097890 1.589734 4.306966 16.42667 0.097890 1.608007 5.809932 16.61333 0.097890 1.626280 6.648817 16.80000 0.097890 1.644553 7.348604 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1001 STAG 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 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 32 Predeveloped HSPF Message File 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 33 Mitigated HSPF Message File ERROR/WARNING ID: 238 1 The continuity error reported below is greater than 1 part in 1000 and is therefore considered high. Did you specify any "special actions"? If so, they could account for it. Relevant data are: DATE/TIME: 2002/ 8/31 24: 0 RCHRES : 1 RELERR STORS STOR MATIN MATDIF -5.993E-03 0.00000 0.0000E+00 0.00000 -7.797E-09 Where: RELERR is the relative error (ERROR/REFVAL). ERROR is (STOR-STORS) - MATDIF. REFVAL is the reference value (STORS+MATIN). STOR is the storage of material in the processing unit (land-segment or reach/reservior) at the end of the present interval. STORS is the storage of material in the pu at the start of the present printout reporting period. MATIN is the total inflow of material to the pu during the present printout reporting period. MATDIF is the net inflow (inflow-outflow) of material to the pu during the present printout reporting period. ERROR/WARNING ID: 238 1 The continuity error reported below is greater than 1 part in 1000 and is therefore considered high. Did you specify any "special actions"? If so, they could account for it. Relevant data are: DATE/TIME: 2006/ 7/31 24: 0 RCHRES : 1 RELERR STORS STOR MATIN MATDIF -3.134E-03 0.00000 0.0000E+00 0.00000 -1.495E-08 Where: RELERR is the relative error (ERROR/REFVAL). ERROR is (STOR-STORS) - MATDIF. REFVAL is the reference value (STORS+MATIN). STOR is the storage of material in the processing unit (land-segment or reach/reservior) at the end of the present interval. STORS is the storage of material in the pu at the start of the present printout reporting period. MATIN is the total inflow of material to the pu during the present printout reporting period. MATDIF is the net inflow (inflow-outflow) of material to the pu during the present printout reporting period. 22298-WWHM-Vault-15.8 8/1/2025 10:00:33 AM Page 34 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com WWHM2012 PROJECT REPORT Harmony Ridge Basins 2 & 3 Figure 4.4.2 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 2 General Model Information WWHM2012 Project Name:22298-WWHM - Basin 2 & 3 Site Name:Harmony Ridge Site Address: City: Report Date:2/7/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.45 Pervious Total 0.45 Impervious Land Use acre Impervious Total 0 Basin Total 0.45 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 4 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.09 Pervious Total 0.09 Impervious Land Use acre Impervious Total 0 Basin Total 0.09 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 5 Mitigated Land Use Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.08 Pervious Total 0.08 Impervious Land Use acre ROADS FLAT 0.13 Impervious Total 0.13 Basin Total 0.21 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 6 Basin 3 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.04 Pervious Total 0.04 Impervious Land Use acre ROADS FLAT 0.05 Impervious Total 0.05 Basin Total 0.09 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 7 Routing Elements Predeveloped Routing 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 8 Mitigated Routing 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:15 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.45 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.08 Total Impervious Area:0.13 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.01323 5 year 0.020779 10 year 0.025057 25 year 0.029589 50 year 0.032393 100 year 0.034778 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.054761 5 year 0.071341 10 year 0.082876 25 year 0.098121 50 year 0.109982 100 year 0.122289 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.013 0.076 1950 0.016 0.071 1951 0.029 0.047 1952 0.009 0.037 1953 0.007 0.040 1954 0.011 0.045 1955 0.018 0.049 1956 0.014 0.049 1957 0.012 0.059 1958 0.013 0.044 Basin 2 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 10 1959 0.011 0.042 1960 0.020 0.049 1961 0.011 0.049 1962 0.007 0.040 1963 0.009 0.048 1964 0.012 0.044 1965 0.009 0.061 1966 0.009 0.038 1967 0.018 0.069 1968 0.011 0.076 1969 0.011 0.056 1970 0.009 0.051 1971 0.010 0.061 1972 0.022 0.070 1973 0.010 0.034 1974 0.011 0.057 1975 0.014 0.059 1976 0.010 0.044 1977 0.001 0.042 1978 0.009 0.054 1979 0.006 0.072 1980 0.021 0.079 1981 0.008 0.056 1982 0.016 0.084 1983 0.014 0.062 1984 0.009 0.041 1985 0.005 0.057 1986 0.023 0.048 1987 0.020 0.072 1988 0.008 0.042 1989 0.005 0.052 1990 0.042 0.118 1991 0.026 0.089 1992 0.010 0.041 1993 0.010 0.034 1994 0.003 0.035 1995 0.015 0.050 1996 0.031 0.059 1997 0.026 0.055 1998 0.006 0.051 1999 0.024 0.114 2000 0.010 0.055 2001 0.002 0.055 2002 0.011 0.075 2003 0.014 0.058 2004 0.019 0.106 2005 0.013 0.049 2006 0.016 0.044 2007 0.031 0.106 2008 0.041 0.088 2009 0.020 0.064 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0424 0.1184 2 0.0406 0.1143 3 0.0315 0.1060 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 11 4 0.0310 0.1058 5 0.0291 0.0893 6 0.0259 0.0877 7 0.0255 0.0837 8 0.0243 0.0793 9 0.0229 0.0758 10 0.0217 0.0758 11 0.0206 0.0748 12 0.0203 0.0721 13 0.0199 0.0717 14 0.0197 0.0712 15 0.0185 0.0697 16 0.0182 0.0686 17 0.0180 0.0643 18 0.0162 0.0623 19 0.0158 0.0612 20 0.0157 0.0611 21 0.0147 0.0593 22 0.0145 0.0587 23 0.0145 0.0585 24 0.0143 0.0582 25 0.0142 0.0574 26 0.0133 0.0567 27 0.0132 0.0564 28 0.0130 0.0556 29 0.0125 0.0554 30 0.0117 0.0552 31 0.0114 0.0548 32 0.0113 0.0536 33 0.0112 0.0525 34 0.0112 0.0512 35 0.0111 0.0507 36 0.0110 0.0495 37 0.0107 0.0494 38 0.0105 0.0492 39 0.0103 0.0490 40 0.0102 0.0489 41 0.0099 0.0487 42 0.0098 0.0477 43 0.0097 0.0476 44 0.0095 0.0471 45 0.0092 0.0446 46 0.0092 0.0443 47 0.0091 0.0442 48 0.0089 0.0441 49 0.0087 0.0440 50 0.0086 0.0423 51 0.0082 0.0420 52 0.0080 0.0419 53 0.0074 0.0413 54 0.0069 0.0409 55 0.0059 0.0397 56 0.0056 0.0395 57 0.0052 0.0380 58 0.0052 0.0366 59 0.0034 0.0350 60 0.0018 0.0345 61 0.0012 0.0339 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 12 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 13 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0066 17547 48574 276 Fail 0.0069 16164 45943 284 Fail 0.0071 14966 43526 290 Fail 0.0074 13851 41195 297 Fail 0.0077 12814 39013 304 Fail 0.0079 11811 36938 312 Fail 0.0082 10898 35078 321 Fail 0.0084 10119 33260 328 Fail 0.0087 9383 31591 336 Fail 0.0090 8731 29987 343 Fail 0.0092 8145 28533 350 Fail 0.0095 7593 27121 357 Fail 0.0097 7060 25731 364 Fail 0.0100 6590 24469 371 Fail 0.0103 6145 23271 378 Fail 0.0105 5777 22095 382 Fail 0.0108 5431 21074 388 Fail 0.0110 5099 20082 393 Fail 0.0113 4808 19100 397 Fail 0.0116 4526 18223 402 Fail 0.0118 4254 17417 409 Fail 0.0121 4017 16576 412 Fail 0.0123 3784 15811 417 Fail 0.0126 3551 15075 424 Fail 0.0129 3339 14431 432 Fail 0.0131 3138 13826 440 Fail 0.0134 2954 13231 447 Fail 0.0136 2789 12645 453 Fail 0.0139 2599 12085 464 Fail 0.0142 2449 11529 470 Fail 0.0144 2308 11043 478 Fail 0.0147 2162 10551 488 Fail 0.0149 2028 10087 497 Fail 0.0152 1903 9687 509 Fail 0.0155 1790 9313 520 Fail 0.0157 1693 8941 528 Fail 0.0160 1590 8551 537 Fail 0.0162 1484 8224 554 Fail 0.0165 1383 7871 569 Fail 0.0168 1293 7542 583 Fail 0.0170 1217 7242 595 Fail 0.0173 1154 6926 600 Fail 0.0176 1098 6646 605 Fail 0.0178 1048 6385 609 Fail 0.0181 997 6124 614 Fail 0.0183 930 5846 628 Fail 0.0186 883 5608 635 Fail 0.0189 837 5390 643 Fail 0.0191 789 5168 655 Fail 0.0194 743 4962 667 Fail 0.0196 713 4774 669 Fail 0.0199 669 4603 688 Fail 0.0202 632 4415 698 Fail 0.0204 596 4231 709 Fail 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 14 0.0207 567 4060 716 Fail 0.0209 539 3914 726 Fail 0.0212 497 3784 761 Fail 0.0215 473 3640 769 Fail 0.0217 435 3512 807 Fail 0.0220 401 3388 844 Fail 0.0222 369 3255 882 Fail 0.0225 348 3151 905 Fail 0.0228 323 3052 944 Fail 0.0230 296 2932 990 Fail 0.0233 273 2825 1034 Fail 0.0235 256 2727 1065 Fail 0.0238 235 2631 1119 Fail 0.0241 217 2545 1172 Fail 0.0243 195 2451 1256 Fail 0.0246 180 2381 1322 Fail 0.0248 158 2308 1460 Fail 0.0251 145 2227 1535 Fail 0.0254 129 2143 1661 Fail 0.0256 119 2066 1736 Fail 0.0259 109 1981 1817 Fail 0.0261 97 1915 1974 Fail 0.0264 91 1852 2035 Fail 0.0267 82 1797 2191 Fail 0.0269 76 1738 2286 Fail 0.0272 69 1684 2440 Fail 0.0274 61 1631 2673 Fail 0.0277 54 1583 2931 Fail 0.0280 48 1534 3195 Fail 0.0282 41 1489 3631 Fail 0.0285 38 1431 3765 Fail 0.0287 33 1375 4166 Fail 0.0290 27 1337 4951 Fail 0.0293 22 1285 5840 Fail 0.0295 21 1244 5923 Fail 0.0298 20 1205 6025 Fail 0.0300 19 1166 6136 Fail 0.0303 17 1137 6688 Fail 0.0306 13 1094 8415 Fail 0.0308 12 1061 8841 Fail 0.0311 8 1030 12875 Fail 0.0314 4 1000 25000 Fail 0.0316 3 974 32466 Fail 0.0319 3 950 31666 Fail 0.0321 3 920 30666 Fail 0.0324 3 888 29600 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. 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. 22298-WWHM - Basin 2 & 3 2/7/2025 3:44:39 PM Page 16 LID Report 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:02 PM Page 17 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.09 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.04 Total Impervious Area:0.05 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.002646 5 year 0.004156 10 year 0.005011 25 year 0.005918 50 year 0.006479 100 year 0.006956 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.021703 5 year 0.028566 10 year 0.03338 25 year 0.039781 50 year 0.044789 100 year 0.050006 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.003 0.030 1950 0.003 0.028 1951 0.006 0.019 1952 0.002 0.014 1953 0.001 0.015 1954 0.002 0.018 1955 0.004 0.019 1956 0.003 0.019 1957 0.002 0.023 1958 0.003 0.017 1959 0.002 0.016 Basin 3 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 18 1960 0.004 0.020 1961 0.002 0.020 1962 0.001 0.015 1963 0.002 0.019 1964 0.002 0.017 1965 0.002 0.025 1966 0.002 0.015 1967 0.004 0.028 1968 0.002 0.030 1969 0.002 0.022 1970 0.002 0.020 1971 0.002 0.024 1972 0.004 0.028 1973 0.002 0.013 1974 0.002 0.023 1975 0.003 0.024 1976 0.002 0.018 1977 0.000 0.017 1978 0.002 0.021 1979 0.001 0.028 1980 0.004 0.032 1981 0.002 0.022 1982 0.003 0.034 1983 0.003 0.024 1984 0.002 0.016 1985 0.001 0.022 1986 0.005 0.019 1987 0.004 0.028 1988 0.002 0.016 1989 0.001 0.020 1990 0.008 0.049 1991 0.005 0.037 1992 0.002 0.016 1993 0.002 0.013 1994 0.001 0.013 1995 0.003 0.019 1996 0.006 0.024 1997 0.005 0.022 1998 0.001 0.020 1999 0.005 0.046 2000 0.002 0.022 2001 0.000 0.021 2002 0.002 0.030 2003 0.003 0.023 2004 0.004 0.042 2005 0.003 0.019 2006 0.003 0.018 2007 0.006 0.044 2008 0.008 0.036 2009 0.004 0.025 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0085 0.0490 2 0.0081 0.0458 3 0.0063 0.0440 4 0.0062 0.0423 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 19 5 0.0058 0.0365 6 0.0052 0.0358 7 0.0051 0.0338 8 0.0049 0.0324 9 0.0046 0.0305 10 0.0043 0.0302 11 0.0041 0.0299 12 0.0041 0.0283 13 0.0040 0.0281 14 0.0039 0.0279 15 0.0037 0.0279 16 0.0036 0.0279 17 0.0036 0.0247 18 0.0032 0.0246 19 0.0032 0.0243 20 0.0031 0.0242 21 0.0029 0.0238 22 0.0029 0.0236 23 0.0029 0.0235 24 0.0029 0.0234 25 0.0028 0.0229 26 0.0027 0.0224 27 0.0026 0.0223 28 0.0026 0.0222 29 0.0025 0.0221 30 0.0023 0.0218 31 0.0023 0.0215 32 0.0023 0.0210 33 0.0022 0.0202 34 0.0022 0.0202 35 0.0022 0.0198 36 0.0022 0.0197 37 0.0021 0.0196 38 0.0021 0.0195 39 0.0021 0.0195 40 0.0020 0.0194 41 0.0020 0.0193 42 0.0020 0.0191 43 0.0019 0.0189 44 0.0019 0.0189 45 0.0018 0.0177 46 0.0018 0.0177 47 0.0018 0.0177 48 0.0018 0.0175 49 0.0017 0.0172 50 0.0017 0.0168 51 0.0016 0.0163 52 0.0016 0.0162 53 0.0015 0.0162 54 0.0014 0.0161 55 0.0012 0.0155 56 0.0011 0.0153 57 0.0010 0.0149 58 0.0010 0.0142 59 0.0007 0.0135 60 0.0004 0.0133 61 0.0002 0.0132 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 20 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 21 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0013 17547 107008 609 Fail 0.0014 16164 103158 638 Fail 0.0014 14966 99650 665 Fail 0.0015 13854 96250 694 Fail 0.0015 12816 93020 725 Fail 0.0016 11813 89812 760 Fail 0.0016 10902 86881 796 Fail 0.0017 10123 83972 829 Fail 0.0017 9392 81342 866 Fail 0.0018 8737 78754 901 Fail 0.0018 8158 76337 935 Fail 0.0019 7602 73856 971 Fail 0.0019 7071 71631 1013 Fail 0.0020 6588 69407 1053 Fail 0.0021 6145 67353 1096 Fail 0.0021 5777 65343 1131 Fail 0.0022 5431 63418 1167 Fail 0.0022 5099 61493 1205 Fail 0.0023 4808 59696 1241 Fail 0.0023 4526 57985 1281 Fail 0.0024 4254 56338 1324 Fail 0.0024 4017 54734 1362 Fail 0.0025 3784 53151 1404 Fail 0.0025 3551 51654 1454 Fail 0.0026 3339 50200 1503 Fail 0.0026 3136 48724 1553 Fail 0.0027 2950 47376 1605 Fail 0.0027 2785 46007 1651 Fail 0.0028 2599 44724 1720 Fail 0.0028 2447 43462 1776 Fail 0.0029 2304 42286 1835 Fail 0.0029 2162 41152 1903 Fail 0.0030 2026 40018 1975 Fail 0.0030 1899 38949 2051 Fail 0.0031 1790 37901 2117 Fail 0.0031 1689 36853 2181 Fail 0.0032 1589 35890 2258 Fail 0.0032 1483 34907 2353 Fail 0.0033 1379 33965 2463 Fail 0.0034 1292 33024 2556 Fail 0.0034 1217 32212 2646 Fail 0.0035 1154 31335 2715 Fail 0.0035 1098 30500 2777 Fail 0.0036 1048 29730 2836 Fail 0.0036 997 28982 2906 Fail 0.0037 930 28233 3035 Fail 0.0037 883 27527 3117 Fail 0.0038 837 26822 3204 Fail 0.0038 789 26116 3310 Fail 0.0039 743 25389 3417 Fail 0.0039 713 24747 3470 Fail 0.0040 668 24105 3608 Fail 0.0040 630 23506 3731 Fail 0.0041 595 22886 3846 Fail 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 22 0.0041 565 22330 3952 Fail 0.0042 539 21795 4043 Fail 0.0042 496 21237 4281 Fail 0.0043 473 20717 4379 Fail 0.0043 434 20185 4650 Fail 0.0044 399 19695 4936 Fail 0.0044 366 19196 5244 Fail 0.0045 348 18737 5384 Fail 0.0046 322 18302 5683 Fail 0.0046 296 17862 6034 Fail 0.0047 272 17447 6414 Fail 0.0047 256 17011 6644 Fail 0.0048 235 16596 7062 Fail 0.0048 217 16189 7460 Fail 0.0049 195 15817 8111 Fail 0.0049 180 15406 8558 Fail 0.0050 158 15075 9541 Fail 0.0050 145 14756 10176 Fail 0.0051 129 14403 11165 Fail 0.0051 119 14082 11833 Fail 0.0052 109 13777 12639 Fail 0.0052 97 13469 13885 Fail 0.0053 91 13154 14454 Fail 0.0053 82 12829 15645 Fail 0.0054 76 12542 16502 Fail 0.0054 68 12252 18017 Fail 0.0055 61 11978 19636 Fail 0.0055 54 11704 21674 Fail 0.0056 48 11413 23777 Fail 0.0056 41 11163 27226 Fail 0.0057 38 10919 28734 Fail 0.0057 33 10664 32315 Fail 0.0058 27 10459 38737 Fail 0.0059 22 10232 46509 Fail 0.0059 21 9999 47614 Fail 0.0060 20 9768 48840 Fail 0.0060 19 9554 50284 Fail 0.0061 17 9364 55082 Fail 0.0061 13 9176 70584 Fail 0.0062 12 8983 74858 Fail 0.0062 8 8787 109837 Fail 0.0063 4 8622 215550 Fail 0.0063 3 8440 281333 Fail 0.0064 3 8260 275333 Fail 0.0064 3 8100 270000 Fail 0.0065 3 7952 265066 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. 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 23 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. 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 24 LID Report 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 25 POC 3 POC #3 was not reported because POC must exist in both scenarios and both scenarios must have been run. 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 26 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. 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:26 PM Page 27 Appendix Predeveloped Schematic 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 28 Mitigated Schematic 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 29 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 22298-WWHM - Basin 2 & 3.wdm MESSU 25 Pre22298-WWHM - Basin 2 & 3.MES 27 Pre22298-WWHM - Basin 2 & 3.L61 28 Pre22298-WWHM - Basin 2 & 3.L62 30 POC22298-WWHM - Basin 2 & 31.dat 31 POC22298-WWHM - Basin 2 & 32.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 2 MAX 1 2 30 9 2 Basin 3 MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 30 <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 31 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 2*** PERLND 10 0.45 COPY 501 12 PERLND 10 0.45 COPY 501 13 Basin 3*** PERLND 10 0.09 COPY 502 12 PERLND 10 0.09 COPY 502 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 32 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 48.4 WDM 502 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 33 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 22298-WWHM - Basin 2 & 3.wdm MESSU 25 Mit22298-WWHM - Basin 2 & 3.MES 27 Mit22298-WWHM - Basin 2 & 3.L61 28 Mit22298-WWHM - Basin 2 & 3.L62 30 POC22298-WWHM - Basin 2 & 31.dat 31 POC22298-WWHM - Basin 2 & 32.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 2 MAX 1 2 30 9 2 Basin 3 MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 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 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 34 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 35 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 2*** PERLND 16 0.08 COPY 501 12 PERLND 16 0.08 COPY 501 13 IMPLND 1 0.13 COPY 501 15 Basin 3*** PERLND 16 0.04 COPY 502 12 PERLND 16 0.04 COPY 502 13 IMPLND 1 0.05 COPY 502 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 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 36 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 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 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 37 Predeveloped HSPF Message File 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 38 Mitigated HSPF Message File 22298-WWHM - Basin 2 & 3 2/7/2025 3:45:27 PM Page 39 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com 425 430 435 440 445 450 455 425 430 435 440 445 450 455 CB#15 CB#12 CB#14 CB#16 CB#13 CB#17 425 430 435 440 445 450 455 460 425 430 435 440 445 450 455 460 CB#14 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 DETENTION VAULT PLAN AND PROFILE 22 SCALE: 1"=10' TRACT B DETENTION VAULT PLAN AND PROFILE SCALE: 1"=20' SCALE: 1"=5' RO A D A SEE CONTINUATION ON SHEET 23 ONSITE VAULT DATA: KEYNOTES SCALE: 1"=20' SCALE: 1"=5' TRACT A18 13 18 14 SITE MAP KEY PLAN R-436022 TE D - 4 0 - 4 3 6 0 NOTE: Figure 4.4.3 CB#17 CB#12 CB#14 CB#16 CB#15 CB#11 CB#13 425 430 435 440 445 450 455 460 425 430 435 440 445 450 455 460 CB#16 TYPE 2-48" (PUBLIC) CB#15 TYPE 2-48" (PUBLIC)CB#14 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CB#17TYPE 2-48" (PUBLIC) 420 425 430 435 440 445 450 455 420 425 430 435 440 445 450 455 CB#12TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CB#13 TYPE 1 MANHOLE (PUBLIC) W/ SOLID LOCKING LIDCB#11 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 DETENTION VAULT PLAN AND PROFILE 23 18 TRACT B TRACT A SEE CONTINUATION ON SHEET 22 SCALE: 1"=10' SE E C O N T I N U A T I O N O N S H E E T 25 ROAD A DETENTION VAULT PLAN AND PROFILE SCALE: 1"=20' SCALE: 1"=5' SITE MAP KEY PLAN R-436023 TE D - 4 0 - 4 3 6 0 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 DETENTION VAULT AND WATER QUALITY DETAILS 24 R-436024 TE D - 4 0 - 4 3 6 0 DETENTION VAULT AND WATER QUALITY DETAILS 420 425 430 435 440 445 450 455 61+0062+0063+0064+00 CB#9 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC)CB#10 TYPE 1 (PUBLIC) BI-DIRECTIONAL GRATE CB#11 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CB#11 CB#9 CB#10 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 TRACT B NOTE: SCALE: 1"=20'SCALE: 1"=5' TRACT A SCALE: 1"=20' SE E C O N T I N U A T I O N O N S H E E T 23 MA T C H L I N E - S T A 6 4 + 2 0 - S E E CO N T I N U A T I O N O N S H E E T 26 25 MA T C H L I N E - S T A 6 4 + 2 0 - S E E CO N T I N U A T I O N O N S H E E T 26 455 450 445 440 435 430 425 420 OFFSITE UTILITY ACCESS ROAD PLAN AND PROFILE OFFSITE UTILITY ACCESS ROAD PLAN AND PROFILE SITE MAP KEY PLAN R-436025 W-436005 S-436005 TE D - 4 0 - 4 3 6 0 WT R - 2 7 - 4 3 6 0 WW P - 2 7 - 4 3 6 0 CB#6 CB#8 CB#5 CB#7 410 415 420 425 430 435 440 445 450 65+0066+0067+0067+60 CB#8 TYPE 2-48" W/ SOLID LOCKING LID CB#6 TYPE 2-48" W/ SOLID LOCKING LIDCB#5 TYPE 2-48" W/ SOLID LOCKING LID (PUBLIC) CB#7 TYPE 1 (PUBLIC) BI-DIRECTIONAL GRATE CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CON S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 SCALE: 1"=20' 450 445 440 435 430 425 420 415 410 26 MA T C H L I N E - S T A 6 4 + 2 0 - S E E CO N T I N U A T I O N O N S H E E T 25 PU G E T D R S E SEE CONTINUATI O N O N S H E E T 27 SEE CONTINUATI O N O N S H E E T 27 MA T C H L I N E - S T A 6 4 + 2 0 - S E E CO N T I N U A T I O N O N S H E E T 25 SCALE: 1"=20' SCALE: 1"=5' OFFSITE UTILITY ACCESS ROAD PLAN AND PROFILE OFFSITE UTILITY ACCESS ROAD PLAN AND PROFILE UTILITY CROSSINGS SITE MAP KEY PLAN NOTE: KEYNOTE CAUTION: PETROLEUM PIPELINES BP FIELD REPRESENTATIVE R-436026 W-436006 S-436006 TE D - 4 0 - 4 3 6 0 WT R - 2 7 - 4 3 6 0 WW P - 2 7 - 4 3 6 0 22298.001-DRNG 4.5 Water Quality System Developed Basin 1, Tract A and Utility Access Road This project is required to provide Basic Water Quality treatment according to the 2022 CORSWDM. A Contech Stormfilter ZPG or approved equal will be implemented to meet water quality requirements and is listed on the city approved proprietary facilities list for both public and private development see Reference 14 for more details . The Contech Stormfilter ZPG is designed per the DOE GULD for the following configurations, see figure 4.5.4 for more details. • Upstream of detention, the water quality design flow rate equals the peak 15-minute flow rate calculated using the latest version of the Western Washington Hydrology Model or another Ecology-approved continuous runoff model, as described in Section III-2.6 of the 2024 Stormwater Management Manual for Western Washington (SWMMWW). • Downstream of detention, the water quality design flow rate equals the full 2-year release rate of the detention facility. The Stormfilter is fitted with a weir to bypass the flows higher than the 2-year flows up to the combined unmitigated 100-year release rate of Developed Basin 1, Tract A and the utility access road, see Figure 4.5.1 for details. The basin breakdown is as follows: Developed Basin 1 Impervious Pervious Total Area 2.73 Ac(1) 1.67 Ac(2,3) 4.40 Ac 2-year (WQ) release rate = 0.152 CFS 100-year unmitigated flow = 2.545 CFS Notes: 1. R/W = 0.96 Ac Lot Area @ 65% Impervious (4,000 SF Max) = 1.63 Ac Tract A = 0.03 Ac Alley Z = 0.11 Ac 2. Modeled as till grass Flat = 1.58 Ac 3. Mitigation Trade (Upstream Building) = 0.09 Ac Tract A and Utility Access Road Impervious Pervious Total Area 0.26 Ac(1) 3.44 Ac(2,3) 3.70 Ac Offline WQ release rate = 0.051 CFS 100-year unmitigated flow = 0.509 CFS Notes: 1. Access Road = 0.26 Ac 2. Till grass = 0.09 Ac 3. Upstream (Forested) = 3.35 Ac 9 – 27” tall ZPG cartridges in a 6’x12’ Peak Diversion Stormfilter will be used to provide basic water quality treatment. 22298.001-DRNG Combined Water Quality flow: (2-year release rate from Basin 1) + (Offline WQ release rate from access road/bypass) = 0.203 cfs Combined unmitigated 100-year flow: (100-year unmitigated flow from Basin 1) + (100-year flow from access road/bypass) = 3.049 cfs Please refer to 4.5.1 – Combined WQ Calc and Figure 4.5.3 – Stormfilter Sizing Coordination Email for sizing details. Developed Basins 2 & 3 According to Section 1.2.8 of the 2022 CORSWDM, any threshold discharge area is exempt from the water quality facility requirement if less than 5,000 square feet of new plus replaced pollution generating surface area will be created. Both Developed Basins 2 and 3 propose less than 5,000 square feet of new plus replaced pollution generating surfaces areas, therefore a water quality facility will not be required for these two basins. CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A NOT F O R CO N S T R U C T I O N DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 OFFSITE WATER QUALITY BASIN MAP 1 SCALE: 1"=40' TRACT B TRACT A OFFSITE WATER QUALITY BASIN MAP CB#10 BASIN CB#7 BASIN PU G E T D R S E 1 CB#10 TERRAIN IMPERVIOUS (AC) PERVIOUS (AC) LAWN PASTURE FORESTED SITE (NOTE 1) FLAT 0.15 0.06 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.21 0.15 0.06 0.00 0.00 MITIGATION TRADE (NOTE 2) FLAT 0.00 0.00 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.00 0.00 0.00 0.00 0.00 UPSTREAM NON-TARGETED AREA (NOTE 3) FLAT 0.00 0.00 0.00 2.81 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:2.81 0.00 0.00 0.00 2.81 TOTAL TO FACILITY:3.02 0.15 0.06 0.00 2.81 CB#7 TERRAIN IMPERVIOUS (AC) PERVIOUS (AC) LAWN PASTURE FORESTED SITE (NOTE 1) FLAT 0.11 0.03 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.14 0.11 0.03 0.00 0.00 MITIGATION TRADE (NOTE 2) FLAT 0.00 0.00 0.00 0.00 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.00 0.00 0.00 0.00 0.00 UPSTREAM NON-TARGETED AREA (NOTE 3) FLAT 0.00 0.00 0.00 0.54 MOD 0.00 0.00 0.00 0.00 STEEP 0.00 0.00 0.00 0.00 SUBTOTAL:0.54 0.00 0.00 0.00 0.54 TOTAL TO FACILITY:0.68 0.11 0.03 0.00 0.54 CB#10 CB#7 COMBINED COMBINED Figure 4.5.1 WWHM2012 PROJECT REPORT FIG 4.5.2 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 2 General Model Information WWHM2012 Project Name:22298-WWHM-Offsite WQ Site Name:Harmony Ridge Site Address: City: Report Date:12/15/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2025/10/07 Version:4.3.2 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 3 Landuse Basin Data Predeveloped Land Use CB#10 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 3.02 Pervious Total 3.02 Impervious Land Use acre Impervious Total 0 Basin Total 3.02 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 4 CB#7 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.68 Pervious Total 0.68 Impervious Land Use acre Impervious Total 0 Basin Total 0.68 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 5 Mitigated Land Use CB#7 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 2.81 C, Lawn, Flat 0.06 Pervious Total 2.87 Impervious Land Use acre ROADS FLAT 0.15 Impervious Total 0.15 Basin Total 3.02 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 6 CB#7 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.54 C, Lawn, Flat 0.03 Pervious Total 0.57 Impervious Land Use acre ROADS FLAT 0.11 Impervious Total 0.11 Basin Total 0.68 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 7 Routing Elements Predeveloped Routing 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 8 Mitigated Routing 22298-WWHM-Offsite WQ 12/15/2025 2:25:06 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:3.7 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:3.44 Total Impervious Area:0.26 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.108783 5 year 0.170848 10 year 0.206021 25 year 0.243284 50 year 0.266343 100 year 0.285955 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.171989 5 year 0.246941 10 year 0.301928 25 year 0.37759 50 year 0.438518 100 year 0.503424 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.107 0.237 1950 0.133 0.237 1951 0.240 0.275 1952 0.075 0.128 1953 0.061 0.102 1954 0.094 0.138 1955 0.149 0.191 1956 0.119 0.180 1957 0.096 0.193 1958 0.108 0.144 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 10 1959 0.093 0.126 1960 0.162 0.238 1961 0.091 0.154 1962 0.057 0.088 1963 0.078 0.143 1964 0.103 0.156 1965 0.074 0.164 1966 0.071 0.127 1967 0.148 0.253 1968 0.092 0.169 1969 0.090 0.160 1970 0.074 0.154 1971 0.080 0.172 1972 0.178 0.228 1973 0.081 0.120 1974 0.088 0.161 1975 0.119 0.219 1976 0.086 0.159 1977 0.010 0.088 1978 0.076 0.128 1979 0.046 0.143 1980 0.169 0.292 1981 0.068 0.136 1982 0.130 0.273 1983 0.117 0.159 1984 0.072 0.117 1985 0.043 0.111 1986 0.189 0.233 1987 0.167 0.235 1988 0.066 0.096 1989 0.043 0.105 1990 0.349 0.526 1991 0.210 0.331 1992 0.081 0.145 1993 0.084 0.117 1994 0.028 0.070 1995 0.121 0.160 1996 0.255 0.332 1997 0.213 0.259 1998 0.048 0.127 1999 0.200 0.327 2000 0.084 0.154 2001 0.015 0.112 2002 0.092 0.169 2003 0.118 0.215 2004 0.152 0.251 2005 0.109 0.189 2006 0.129 0.183 2007 0.259 0.418 2008 0.334 0.427 2009 0.164 0.255 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.3487 0.5262 2 0.3339 0.4271 3 0.2588 0.4177 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 11 4 0.2549 0.3321 5 0.2395 0.3314 6 0.2131 0.3267 7 0.2100 0.2916 8 0.1998 0.2747 9 0.1886 0.2726 10 0.1784 0.2593 11 0.1691 0.2547 12 0.1668 0.2532 13 0.1639 0.2511 14 0.1620 0.2378 15 0.1522 0.2370 16 0.1495 0.2367 17 0.1479 0.2346 18 0.1332 0.2334 19 0.1299 0.2282 20 0.1288 0.2192 21 0.1209 0.2146 22 0.1192 0.1928 23 0.1190 0.1911 24 0.1176 0.1894 25 0.1165 0.1833 26 0.1092 0.1796 27 0.1082 0.1719 28 0.1069 0.1688 29 0.1028 0.1686 30 0.0960 0.1643 31 0.0938 0.1611 32 0.0928 0.1599 33 0.0923 0.1597 34 0.0922 0.1595 35 0.0914 0.1591 36 0.0903 0.1565 37 0.0880 0.1545 38 0.0862 0.1545 39 0.0843 0.1541 40 0.0841 0.1446 41 0.0810 0.1442 42 0.0810 0.1430 43 0.0796 0.1427 44 0.0781 0.1375 45 0.0756 0.1359 46 0.0755 0.1282 47 0.0744 0.1279 48 0.0736 0.1272 49 0.0719 0.1268 50 0.0707 0.1264 51 0.0676 0.1196 52 0.0658 0.1171 53 0.0611 0.1169 54 0.0569 0.1116 55 0.0482 0.1113 56 0.0457 0.1049 57 0.0429 0.1021 58 0.0427 0.0963 59 0.0283 0.0884 60 0.0151 0.0882 61 0.0103 0.0700 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 12 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 13 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0544 17547 23763 135 Fail 0.0565 16161 21710 134 Fail 0.0587 14964 19913 133 Fail 0.0608 13851 18328 132 Fail 0.0630 12814 16957 132 Fail 0.0651 11811 15657 132 Fail 0.0672 10900 14504 133 Fail 0.0694 10119 13400 132 Fail 0.0715 9383 12440 132 Fail 0.0737 8731 11582 132 Fail 0.0758 8143 10769 132 Fail 0.0779 7593 10012 131 Fail 0.0801 7060 9377 132 Fail 0.0822 6588 8772 133 Fail 0.0844 6145 8209 133 Fail 0.0865 5777 7666 132 Fail 0.0886 5431 7197 132 Fail 0.0908 5097 6765 132 Fail 0.0929 4808 6346 131 Fail 0.0951 4524 5965 131 Fail 0.0972 4252 5642 132 Fail 0.0994 4017 5332 132 Fail 0.1015 3794 5050 133 Fail 0.1036 3551 4753 133 Fail 0.1058 3341 4477 134 Fail 0.1079 3138 4209 134 Fail 0.1101 2954 3974 134 Fail 0.1122 2791 3754 134 Fail 0.1143 2599 3557 136 Fail 0.1165 2451 3375 137 Fail 0.1186 2306 3191 138 Fail 0.1208 2162 3005 138 Fail 0.1229 2024 2845 140 Fail 0.1250 1901 2684 141 Fail 0.1272 1790 2522 140 Fail 0.1293 1688 2366 140 Fail 0.1315 1590 2248 141 Fail 0.1336 1483 2129 143 Fail 0.1357 1382 2018 146 Fail 0.1379 1293 1908 147 Fail 0.1400 1221 1813 148 Fail 0.1422 1155 1713 148 Fail 0.1443 1098 1617 147 Fail 0.1465 1049 1520 144 Fail 0.1486 998 1443 144 Fail 0.1507 930 1362 146 Fail 0.1529 884 1284 145 Fail 0.1550 837 1207 144 Fail 0.1572 789 1144 144 Fail 0.1593 743 1087 146 Fail 0.1614 713 1032 144 Fail 0.1636 671 992 147 Fail 0.1657 630 950 150 Fail 0.1679 596 909 152 Fail 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 14 0.1700 565 859 152 Fail 0.1721 539 820 152 Fail 0.1743 497 775 155 Fail 0.1764 473 737 155 Fail 0.1786 436 696 159 Fail 0.1807 399 663 166 Fail 0.1828 368 628 170 Fail 0.1850 348 599 172 Fail 0.1871 323 571 176 Fail 0.1893 296 541 182 Fail 0.1914 272 510 187 Fail 0.1936 256 486 189 Fail 0.1957 235 464 197 Fail 0.1978 217 442 203 Fail 0.2000 198 414 209 Fail 0.2021 180 377 209 Fail 0.2043 158 354 224 Fail 0.2064 145 334 230 Fail 0.2085 129 312 241 Fail 0.2107 119 290 243 Fail 0.2128 109 274 251 Fail 0.2150 97 253 260 Fail 0.2171 91 236 259 Fail 0.2192 82 223 271 Fail 0.2214 76 207 272 Fail 0.2235 69 189 273 Fail 0.2257 61 174 285 Fail 0.2278 54 162 300 Fail 0.2299 48 151 314 Fail 0.2321 41 142 346 Fail 0.2342 38 133 350 Fail 0.2364 33 128 387 Fail 0.2385 27 115 425 Fail 0.2407 22 105 477 Fail 0.2428 21 101 480 Fail 0.2449 20 99 494 Fail 0.2471 19 89 468 Fail 0.2492 17 83 488 Fail 0.2514 14 76 542 Fail 0.2535 12 71 591 Fail 0.2556 9 67 744 Fail 0.2578 4 58 1450 Fail 0.2599 3 52 1733 Fail 0.2621 3 47 1566 Fail 0.2642 3 44 1466 Fail 0.2663 3 42 1400 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. 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.1623 acre-feet On-line facility target flow:0.0944 cfs. Adjusted for 15 min:0.0944 cfs. Off-line facility target flow:0.0513 cfs. Adjusted for 15 min:0.0513 cfs. 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 16 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. 22298-WWHM-Offsite WQ 12/15/2025 2:25:25 PM Page 17 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 18 Appendix Predeveloped Schematic 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 19 Mitigated Schematic 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 20 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 22298-WWHM-Offsite WQ.wdm MESSU 25 Pre22298-WWHM-Offsite WQ.MES 27 Pre22298-WWHM-Offsite WQ.L61 28 Pre22298-WWHM-Offsite WQ.L62 30 POC22298-WWHM-Offsite WQ1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 CB#10 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 21 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 22 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** CB#10*** PERLND 10 3.02 COPY 501 12 PERLND 10 3.02 COPY 501 13 CB#7*** PERLND 10 0.68 COPY 501 12 PERLND 10 0.68 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 23 <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 END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 24 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 22298-WWHM-Offsite WQ.wdm MESSU 25 Mit22298-WWHM-Offsite WQ.MES 27 Mit22298-WWHM-Offsite WQ.L61 28 Mit22298-WWHM-Offsite WQ.L62 30 POC22298-WWHM-Offsite WQ1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 CB#7 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 25 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 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 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 26 <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# *** CB#7*** PERLND 10 2.81 COPY 501 12 PERLND 10 2.81 COPY 501 13 PERLND 16 0.06 COPY 501 12 PERLND 16 0.06 COPY 501 13 IMPLND 1 0.15 COPY 501 15 CB#7*** PERLND 10 0.54 COPY 501 12 PERLND 10 0.54 COPY 501 13 PERLND 16 0.03 COPY 501 12 PERLND 16 0.03 COPY 501 13 IMPLND 1 0.11 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 27 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 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 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 28 Predeveloped HSPF Message File 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 29 Mitigated HSPF Message File 22298-WWHM-Offsite WQ 12/15/2025 2:25:26 PM Page 30 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Office: (503) 258-3173 |Fax: (800) 561-1271 Jordan.Drugge@ContechES.com www.ContechES.com *Licensed in Washington From: Austin Ng <ang@core-states.com> Sent: Tuesday, December 16, 2025 9:41 AM To: Jordan Drugge <Jordan.Drugge@ContechES.com> Cc: Jelena Vandenhaak <Jelena.Vandenhaak@ContechES.com>; Trent Skoda <tskoda@core-states.com> Subject: RE: [EXTERNAL] Harmony Ridge Stormfilter design revision BCE#22298 Thank you Jordan! Please send the updated detail when possible. Thanks, From: Jordan Drugge <Jordan.Drugge@ContechES.com> Sent: Tuesday, December 16, 2025 9:25 AM To: Austin Ng <ang@core-states.com> Cc: Jelena Vandenhaak <Jelena.Vandenhaak@ContechES.com>; Trent Skoda <tskoda@core-states.com> Subject: RE: [EXTERNAL] Harmony Ridge Stormfilter design revision BCE#22298 Austin, Thanks for confirmation. Please see updated sizing below: StormFilter Estimate (SF-1) Basic Treatment 2-year release rate from vault: 0.203CFS 100-year unmitigated flow: 3.049 CFS (9) 27” tall ZPG cartridges in an 6x12 SFPD - Recommended min. drop of 3.05’ from inlet to outlet invert Rim to outlet invert depth provided = 9.10’ Drop from inlet to outlet invert provided = 3.05’ Two inlet pipes Approx. $47K Note that the number of cartridges was reduced, but the same vault size is still needed. 12/29/25, 1:57 PM Mail - Austin Ng - Outlook https://outlook.office.com/mail/id/AAQkADg5YWM0OGNhLTUwMTMtNGJmOS1iNzExLTQyNGRiYTFiNTU3ZAAQAD2ijAV%2FJ0otq5wNLzQXjWo%3D 2/5 FIG 4.5.3 Let me know if you have any questions or need anything else, Thanks again! Jordan Drugge, P.E.* Design Engineer – Stormwater Contech Engineered Solutions LLC 12901 SE 97th Ave, Suite 400 | Clackamas, OR 97015 Office: (503) 258-3173 |Fax: (800) 561-1271 Jordan.Drugge@ContechES.com www.ContechES.com *Licensed in Washington From: Austin Ng <ang@core-states.com> Sent: Tuesday, December 16, 2025 8:57 AM To: Jordan Drugge <Jordan.Drugge@ContechES.com> Cc: Jelena Vandenhaak <Jelena.Vandenhaak@ContechES.com>; Trent Skoda <tskoda@core-states.com> Subject: RE: [EXTERNAL] Harmony Ridge Stormfilter design revision BCE#22298 Good morning Jordan, Thank you for the quick response! No, the peak flow rate did not change, only the water quality rate. Thanks, From: Jordan Drugge <Jordan.Drugge@ContechES.com> Sent: Tuesday, December 16, 2025 8:21 AM To: Austin Ng <ang@core-states.com> Cc: Jelena Vandenhaak <Jelena.Vandenhaak@ContechES.com>; Trent Skoda <tskoda@core-states.com> Subject: RE: [EXTERNAL] Harmony Ridge Stormfilter design revision BCE#22298 Good morning Austin, I noticed that in the attached updated design, the 2-yr release rate decreased from 0.329 cfs to 0.203 cfs, did the peak flowrate also decrease or is it still the same? I ask since you may be able to decrease the size significantly if the peak flow was reduced by enough to use a different StormFilter model. 12/29/25, 1:57 PM Mail - Austin Ng - Outlook https://outlook.office.com/mail/id/AAQkADg5YWM0OGNhLTUwMTMtNGJmOS1iNzExLTQyNGRiYTFiNTU3ZAAQAD2ijAV%2FJ0otq5wNLzQXjWo%3D 3/5 P a g e | 1 April 2025 GENERAL USE LEVEL DESIGNATION FOR BASIC (TSS) TREATMENT For CONTECH Engineered Solutions Stormwater Management StormFilter® with ZPG Media Ecology’s Decision: Based on the CONTECH Engineered Solutions’ (CONTECH) application submissions for the StormFilter® with ZPG Media (StormFilter ZPG) Ecology hereby issues the following use level designation: 1. General Use Level Designation (GULD) for Basic Treatment (total suspended solids). • Using ZPG™ media (zeolite/perlite/granular activated carbon), with the size distribution described below, • Sized at a hydraulic loading rate of 1 gpm/ft2 of media surface area, per Table 1, and • Internal bypassing needs to be consistent with the design guidelines in CONTECH’s current product design manual. Table 1. StormFilter Design Flow Rates per Cartridge 2. 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 Testing Vancouver, WA Commercial 114 <62.52 1003 Lake Stevens, WA Roadway 115 <62.52 803 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 D50 PSD was not reported. On average 90% of the particles captured at the Vancouver site and 67% of the particles captured at the Lake Stevens site were less than 62.5 µm. A D50 of less than 62.5 µm (meaning greater than 50% of particles are less than 62.5 µm) is considered representative of Pacific Northwest stormwater. Effective Cartridge Height (inches) 12 18 27 Cartridge Flow Rate (gpm/cartridge) 5 7.5 11.3 FIG 4.5.4 P a g e | 2 3 Maintenance was not needed during the GULD testing. Testing at Vancouver, WA lasted 12 months (100% of a water year) while testing at Lake Stevens, WA lasted 9.5 months (80% of a water year). It is possible the Lake Stevens system could have demonstrated a longer maintenance cycle if testing had continued. 3 Maintenance assessment data are collected after issuing of the GULD. Maintenance assessment results for the StormFilter with ZPG will be based on testing completed on the StormFilter with PhosphoSorb. Assessment shall be completed by February 28, 2028. 3. Ecology approves StormFilter systems containing ZPG™ media for treatment at the hydraulic loading rates shown in Table 1, and sized based on the water quality design flow rate for an off-line system when using an external bypass vault or a treatment vault with an internal bypass. Contech designs their StormFilter systems to maintain treatment of the water quality design flow while routing excess flows around the treatment chamber during periods of peak bypass. 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 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 the detention, the water quality design flow rate is full 2-year release rate of the detention facility. 4. The GULD designation has no expiration date but it may be amended or revoked by Ecology and is subject to the conditions specified below. Ecology’s Conditions of Use: The StormFilter with ZPG media shall comply with the following conditions: 1. Design, install, operate, and maintain the StormFilter with ZPG media in accordance with applicable Contech Engineered Solutions manuals, documents, and the Ecology Decision. 2. Install StormFilter systems to bypass flows exceeding the water quality treatment rate. Additionally, high flows will not re-suspend captured sediments. Design StormFilter systems in accordance with the performance goals in Ecology's most recent Stormwater Manual and CONTECH’s most recent Product Design Manual, unless otherwise specified. 3. Owners must follow the design, pretreatment, land use application, and maintenance criteria in CONTECH’s Design Manual. 4. Pretreatment of TSS and oil and grease may be necessary, and designers shall provide pre- treatment in accordance with the most current versions of the CONTECH’s Product Design Manual or the applicable Ecology Stormwater Manual. P a g e | 3 5. 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 filter treatment device. • Typically, CONTECH designs StormFilter systems for a target filter media replacement interval of 12 months. Maintenance includes removing accumulated sediment from the vault, and replacing spent cartridges with recharged cartridges. • Indications of the need for maintenance include effluent flow decreasing to below the design flow rate, as indicated by the scumline above the shoulder of the cartridge. • Owners/operators must inspect StormFilter with ZPG media for a minimum of twelve months from the start of post-construction operation to determine site-specific maintenance schedules and requirements. You 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 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 flowrate and/or a decrease in pollutant removal ability. • When inspections are performed, the following findings typically serve as maintenance triggers: • Accumulated vault sediment depths exceed an average of 2 inches, or • Accumulated sediment depths on the tops of the cartridges exceed an average of 0.5 inches, or • Standing water remains in the vault between rain events, or • Bypass occurs during storms smaller than the design storm. • Note: If excessive floatables (trash and debris) are present, perform a minor maintenance consisting of gross solids removal, not cartridge replacement. 6. CONTECH shall maintain readily available reports listed under “Application Documents” (below) as public, as well as the documentation submitted with its previous conditional use designation application. CONTECH shall provide links to this information from its corporate website, and make this information available upon request, at no cost and in a timely manner. 7. ZPG™ media used shall conform with the following specifications: • Each cartridge contains a total of approximately 2.6 cubic feet of media. The ZPG™ cartridge consists of an outer layer of perlite that is approximately 1.3 cubic feet in volume and an inner layer, consisting of a mixture of 90% zeolite and 10% granular activated carbon, which is approximately 1.3 cubic feet in volume. P a g e | 4 • Perlite Media: Perlite media shall be made of natural siliceous volcanic rock free of any debris or foreign matter. The expanded perlite shall have a bulk density ranging from 6.5 to 8.5 lbs per cubic foot and particle sizes ranging from 0.09” (#8 mesh) to 0.38” (3/8” mesh). • Zeolite Media: Zeolite media shall be made of naturally occurring clinoptilolite. The zeolite media shall have a bulk density ranging from 44 to 50 lbs per cubic foot and particle sizes ranging from 0.13” (#6 mesh) to 0.19” (#4 mesh). Additionally, the cation exchange capacity (CEC) of zeolite shall range from approximately 1.0 to 2.2 meq/g. • Granular Activated Carbon: Granular activated carbon (GAC) shall be made of lignite coal that has been steam-activated. The GAC media shall have a bulk density ranging from 28 to 31 lbs per cubic foot and particle sizes ranging from a 0.09” (#8 mesh) to 0.19” (#4 mesh). Approved Alternate Configurations Peak Diversion StormFilter 1. The Peak Diversion StormFilter allows for off-line bypass within the StormFilter structure. Design capture flows and peak flows enter the inlet bay which contains an internal weir. The internal weir allows design flows to enter the cartridge bay through a transfer hole located at the bottom of the inlet bay while the unit routs higher flows around the cartridge bay. 2. To select the size of the Peak Diversion StormFilter unit, the designer must determine the number of cartridges required and size of the standard StormFilter using the site-specific water quality design flow and the StormFilter Design Flow Rates per Cartridge as described above. 3. New owners may not install the Peak Diversion StormFilter at an elevation or in a location where backwatering may occur. Applicant: Contech Engineered Solutions Applicant’s Address: 11835 NE Glenn Widing Dr. Portland, OR 97220 Application Documents: The applicant’s master report, titled, “The Stormwater Management StormFilter Basic Treatment Application for General Use Level Designation in Washington”, Stormwater Management, Inc., November 1, 2004, includes the following reports. Documents noted as “public” are available by contacting CONTECH: (Public) Evaluation of the Stormwater Management StormFilter Treatment System: Data Validation Report and Summary of the Technical Evaluation Engineering Report (TEER) by Stormwater Management Inc., October 29, 2004 Ecology’s technology assessment protocol requires the applicant to hire an independent consultant to complete the following work: P a g e | 5 1. Complete the data validation report. 2. Prepare a TEER summary, including a testing summary and conclusions compared with the supplier’s performance claims. 3. Provide a recommendation of the appropriate technology use level. 4. Work with Ecology to post recommend relevant information on Ecology’s website. 5. Provide additional testing recommendations, if needed.” 6. This report, authored by Dr. Gary Minton, Ph. D., P.E., Resource Planning Associates, satisfies the Ecology requirement. (Public) “Performance of the Stormwater Management StormFilter Relative to the Washington State Department of Ecology Performance Goals for Basic Treatment,” is a summary of StormFilter performance that strictly adheres to the criteria listed in the Guidance for Evaluating Emerging Stormwater Treatment Technologies, Technology Assessment Protocol – Ecology (TAPE). “Heritage Marketplace Field Evaluation: Stormwater Management StormFilter with ZPG™ Media,” is a report showing all of the information collected at Site A as stated in the SMI Quality Assurance Project Plan (QAPP). This document contains detailed information regarding each storm event collected at this site, and it provided a detailed overview of the data and project. “Lake Stevens Field Evaluation: Stormwater Management StormFilter with ZPG™ Media,” is a report that corresponds to Site E as stated in the SMI QAPP. This document contains detailed information regarding each storm collected at this site, and includes a detailed overview of the data and project. (Public) “Evaluation of the Stormwater Management StormFilter for the removal of SIL-CO-SIL 106, a standardized silica product: ZPG™ at 7.5 GPM” is a report that describes laboratory testing at full design flow. “Factors Other Than Treatment Performance.” “State of Washington Installations.” “Peak Diversion StormFilter” is a technical document demonstrating the Peak Diversion StormFilter system complies with the Stormwater Management Manual for Western Washington Volume V Section 4.5.1. Applicant's Use Level Request: That Ecology grant a General Use Level Designation for Basic Treatment for the StormFilter using ZPG™ media (zeolite/perlite/granular activated carbon) at a hydraulic loading rate of 1 gpm/ft2 of media surface area in accordance with Ecology's 2011 Technical Guidance Manual for Evaluating Emerging Stormwater Treatment Technologies Technology Assessment Protocol – Ecology (TAPE). P a g e | 6 Applicant's Performance Claim: The combined data from the two field sites reported in the TER (Heritage Marketplace and Lake Stevens) indicate that the performance of a StormFilter system configured for inline bypass with ZPG™ media and a hydraulic loading rate of 1 gpm/ft2 of media surface area meets Ecology performance goals for Basic Treatment. Ecology’s Recommendations: Based on the weight of the evidence and using its best professional judgment, Ecology finds that: • StormFilter, using ZPG™ media and operating at a hydraulic loading rate of no more than 1 gpm/ft2 of media surface area, is expected to provide effective stormwater treatment achieving Ecology’s Basic Treatment (TSS removal) performance goals. Contech demonstrated this through field and laboratory testing performed in accordance with the approved protocol. Findings of Fact: • Influent TSS concentrations and particle size distributions were generally within the range of what Ecology considers “typical” for western Washington (silt-to-silt loam). • Contech sampled thirty-two (32) storm events at two sites for storms from April 2003 to March 2004, of which Contech deemed twenty-two (22) as “qualified” and were therefore included in the data analysis set. • Statistical analysis of these 22 storm events verifies the data set’s adequacy. • Analyzing all 22 qualifying events, the average influent and effluent concentrations and aggregate pollutant load reduction are 114 mg/L, 25 mg/L, and 82%, respectively. • Analyzing all 22 qualifying events based on the estimated average flow rate during the event (versus the measured peak flow rate), and more heavily weighting those events near the design rate (versus events either far above or well below the design rate) does not significantly affect the reported results. • For the 7 qualifying events with influent TSS concentrations greater than 100 mg/L, the average influent and effluent concentrations and aggregate pollutant load reduction are 241 mg/L, 34 mg/L, and 89%, respectively. If we exclude the 2 of 7 events that exceed the maximum 300 mg/L specified in Ecology’s guidelines, the average influent and effluent concentrations and aggregate pollutant load reduction are 158 mg/L, 35 mg/L, and 78%, respectively. • For the 15 qualifying events with influent TSS concentrations less than 100 mg/L, the average influent and effluent concentrations and aggregate pollutant load reduction are 55 mg/L, 20 mg/L, and 61%, respectively. If the 6 of 15 events that fall below the minimum 33 mg/L TSS specified in Ecology’s guidelines are excluded, the average influent and effluent concentrations and aggregate pollutant load reduction are 78 mg/L, 26 mg/L, and 67%, respectively. • For the 8 qualifying events with peak discharge exceeding design flow (ranging from 120 to 257% of the design rate), results ranged from 52% to 96% TSS removal, with an average of 72%. P a g e | 7 • Due to the characteristics of the hydrographs, the field results generally reflect flows below (ranging between 20 and 60 percent of) the tested facilities’ design rate. During these sub- design flow rate periods, some of the cartridges operate at or near their individual full design flow rate (generally between 4 and 7.5 GPM for an 18” cartridge effective height) because their float valves have opened. Float valves remain closed on the remaining cartridges, which operate at their base “trickle” rate of 1 to 1.5 GPM. • Laboratory testing using U.S. Silica’s Sil-Co-Sil 106 fine silica product showed an average 87% TSS removal for testing at 7.5 GPM per cartridge (100% design flow rate). • Other relevant testing at I-5 Lake Union, Greenville Yards (New Jersey), and Ski Run Marina (Lake Tahoe) facilities shows consistent TSS removals in the 75 to 85% range. Note that the evaluators operated the I-5 Lake Union at 50%, 100%, and 125% of design flow. • SMI’s application included a satisfactory “Factors other than treatment performance” discussion. Note: Ecology’s 80% TSS removal goal applies to 100 mg/l and greater influent TSS. Below 100 mg/L influent TSS, the goal is 20 mg/L effluent TSS. Technology Description: The Stormwater Management StormFilter® (StormFilter), a flow-through stormwater filtration system, improves the quality of stormwater runoff from the urban environment by removing pollutants. The StormFilter can treat runoff from a wide variety of sites including, but not limited to: retail and commercial development, residential streets, urban roadways, freeways, and industrial sites such as shipyards, foundries, etc. Operation: The StormFilter is typically comprised of a vault that houses rechargeable, media-filled, filter cartridges. Various media may be used, but this designation covers only the zeolite-perlite- granulated activated carbon (ZPG™) medium. Stormwater from storm drains percolates through these media-filled cartridges, which trap particulates and may remove pollutants such as dissolved metals, nutrients, and hydrocarbons. During the filtering process, the StormFilter system also removes surface scum and floating oil and grease. Once filtered through the media, the treated stormwater is directed to a collection pipe or discharged to an open channel drainage way. This document includes a bypass schematic for flow rates exceeding the water quality design flow rate on page 8. StormFilter Configurations: Contech offers the StormFilter in multiple configurations: precast, high flow, catch basin, curb inlet, linear, volume, corrugated metal pipe, drywell, and CON/Span form. Most configurations use pre-manufactured units to ease the design and installation process. Systems may be either uncovered or covered underground units. P a g e | 8 The typical precast StormFilter unit is composed of three sections: the energy dissipater, the filtration bay, and the outlet sump. As Stormwater enters the inlet of the StormFilter vault through the inlet pipe, piping directs stormwater through the energy dissipater into the filtration bay where treatment will take place. Once in the filtration bay, the stormwater ponds and percolates horizontally through the media contained in the StormFilter cartridges. After passing through the media, the treated water in each cartridge collects in the cartridge’s center tube from where piping directs it into the outlet sump by a High Flow Conduit under-drain manifold. The treated water in the outlet sump discharges through the single outlet pipe to a collection pipe or to an open channel drainage way. In some applications where you anticipate heavy grit loads, pretreatment by settling may be necessary. P a g e | 9 Figure 1. Stormwater Management StormFilter Configuration with Bypass P a g e | 10 Figure 2. The StormFilter Cartridge Cartridge Operation: As the water level in the filtration bay begins to rise, stormwater enters the StormFilter cartridge. Stormwater in the cartridge percolates horizontally through the filter media and passes into the cartridge’s center tube, where the float in the cartridge is in a closed (downward) position. As the water level in the filtration bay continues to rise, more water passes through the filter media and into the cartridge’s center tube. Water displaces the air in the cartridge and it purges from beneath the filter hood through the one-way check valve located in the cap. Once water fills the center tube there is enough buoyant force on the float to open the float valve and allow the treated water to flow into the under-drain manifold. As the treated water drains, it tries to pull in air behind it. This causes the check valve to close, initiating a siphon that draws polluted water throughout the full surface area and volume of the filter. Thus, water filters through the entire filter cartridge throughout the duration of the storm, regardless of the water surface elevation in the filtration bay. This continues until the water surface elevation drops to the elevation of the scrubbing regulators. At this point, the siphon begins to break and air quickly flows beneath the hood through the scrubbing regulators, causing energetic bubbling between the inner surface of the hood and the outer surface of the filter. This bubbling agitates and cleans the surface of the filter, releasing accumulated sediments on the surface, flushing them from beneath the hood, and allowing them to settle to the vault floor. Adjustable cartridge flow rate: Inherent to the design of the StormFilter is the ability to control the individual cartridge flow rate with an orifice-control disc placed at the base of the cartridge. Depending on the treatment requirements and on the pollutant characteristics of the influent stream as specified in the CONTECH Product Design Manual, operators may adjust the flow rate through the filter cartridges. By decreasing the flow rate through the filter cartridges, the influent contact time P a g e | 11 with the media is increased and the water velocity through the system is decreased, thus increasing both the level of treatment and the solids removal efficiencies of the filters, respectively (de Ridder, 2002). Other StormFilter with ZPG items the Company should address: 1. Conduct hydraulic testing on a StormFilter with Phosphosorb at one site in the Pacific Northwest as outlined in the 2024 TAPE Guidance Document to obtain information about maintenance longevity and requirements. Complete testing by February 28, 2028. Contact Information: Applicant Contact: Jeremiah Lehman Contech Engineered Solutions 11835 NE Glenn Widing Drive Portland, OR, 97220 503-258-3136 jlehman@conteches.com Applicant Web link http://www.conteches.com/ Ecology web link: http://www.ecy.wa.gov/programs/wq/stormwater/newtech/index.html Ecology Contact: Douglas C. Howie, P.E. Department of Ecology Water Quality Program (360) 407-6444 douglas.howie@ecy.wa.gov Revision History Date Revision Jan 2005 Original Use Level Designation Dec 2007 Revision May 2012 Maintenance requirements updated November 2012 Design Storm and Maintenance requirements updated January 2013 Updated format to match Ecology standard format September 2014 Added Peak Diversion StormFilter Alternate Configuration November 2016 Revised Contech contact information April 2017 Revised sizing language to note sizing based on Off-line calculations April 2025 Added requirement for maintenance assessment Section 5.0 22298.001-DRNG 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN The onsite and frontage conveyance system will be designed in accordance with the 2022 CORSWDM. The proposed conveyance system for this project is curb, gutter, catch basins, and storm drainage pipe. The storm drainage pipe used will consist of smooth-walled corrugated polyethylene pipe with a Manning's roughness coefficient of 0.012. 100-year conveyance calculations for the pipes will be completed using the rational method. The design intent of the conveyance system is to fully accommodate the 100-year storm event flowing at full condition. Please see Figure 5.0.1 Conveyance Analysis provided within this section. A 100-year backwater analysis to determine the hydraulic grade line and to see if any catch basin rims overtop has also been performed using KCBW in accordance with the 2022 City of Renton Amendments to the KCSWDM. Please see Figure 5.0.2 Backwater Analysis in this section CB#26 CB#27 CB#28 CB#33 CB#32 CB#31 CB#21 CB#20 CB#19 CB#18 CB#1 CB#3 CB#4 CB#5 CB#6 CB#10 CB#14 CB#15 CB#17 CB#16 CB#35 EX CB#1 CB#34 EX CB#5 CB#2 CB#9 CB#13 CB#29 CB#30 CB#23 CB#22 CB#24 CB#25 CB#11 CB#12 CB#7 CB#8 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD 1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T O N SK O D A DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 CONVEYANCE ANALYSIS MAP 1 SCALE: 1"=50' 1 2 3 4 5 6 11 10 9 8 7 17 16 15 14 13 12 18 19 20 TRACT D TRACT C TRACT B TRACT A ROAD A RO A D B ALLEY Z 11 6 T H A V E S E R O L L I N G H I L L S A V E S E PU G E T D R S E CA M A S C I R S E SE 1 9 T H S T S E 1 9 T H S T ABE R D E E N A V E S E CONVEYANCE ANALYSIS MAP DEVELOPED BASIN 2 BYPASS BASIN BYPASS BASIN EX BUILDING UPSTREAM BASIN 1 STORMFILTER Figure 5.0.1 22298 kingco - REV.xls BARGHAUSEN CONSULTING ENGINEERS - PIPE FLOW CALCULATOR using the Rational Method & Manning Formula KING COUNTY DESIGN FOR 100 YEAR STORM JOB NAME:Harmony Ridge NOTE: ENTER DEFAULTS AND STORM DATA BEFORE BEGINNING JOB#:22298 DEFAULTS C=0.68 n=0.012 FILE NO.: d=12 Tc=6.3 A= Contributing Area (Ac)Qd= Design Flow (cfs)COEFFICIENTS FOR THE RATIONAL METHOD "Ir"-EQUATION C= Runoff Coefficient Qf= Full Capacity Flow (cfs)STOR M Ar Br Tc= Time of Concentration (min)Vd= Velocity at Design Flow (fps)2YR 1.58 0.58 I= Intensity at Tc (in/hr)Vf= Velocity at Full Flow (fps)10YR 2.44 0.64 PRECIP=3.9 d= Diameter of Pipe (in)s= Slope of pipe (%)25YR 2.66 0.65 Ar=2.61 L= Length of Pipe (ft)n= Manning Roughness Coefficient 50YR 2.75 0.65 Br=0.63 D= Water Depth at Qd (in)Tt= Travel Time at Vd (min)100YR 2.61 0.63 FROM TO A s L d Tc n C SUM A A*C SUM A*C I Qd Qf Qd/Qf D/d D Vf Vd Tt Qr ======================================================================================================================================= 28 27 0.89 0.60 150 12 6.3 0.012 0.68 0.89 0.61 0.61 3.19 1.93 2.99 0.646 0.590 7.08 3.81 4.06 0.62 - 27 26 0.63 1.00 169 18 6.9 0.012 0.68 1.52 0.43 1.03 3.01 3.11 11.38 0.273 0.359 6.46 6.44 5.50 0.51 0.38 26 25 0.21 1.00 25 18 7.4 0.012 0.68 1.73 0.14 1.18 2.88 3.39 11.38 0.298 0.373 6.71 6.44 5.61 0.07 0.08 25 24 0.31 3.02 113 18 7.5 0.012 0.68 2.04 0.21 1.39 2.86 3.97 19.77 0.201 0.301 5.41 11.20 8.69 0.22 0.15 33 32 0.60 0.60 111 12 6.3 0.012 0.68 0.6 0.41 0.41 3.19 1.30 2.99 0.436 0.463 5.56 3.81 3.71 0.50 - 32 31 0.64 0.60 24 18 6.8 0.012 0.68 1.24 0.44 0.84 3.04 2.57 8.81 0.291 0.369 6.65 4.99 4.32 0.09 0.49 31 29 0.10 0.60 160 18 6.9 0.012 0.68 1.34 0.07 0.91 3.02 2.75 8.81 0.312 0.382 6.87 4.99 4.40 0.61 0.07 29 24 0.03 0.60 78 18 7.5 0.012 0.68 1.37 0.02 0.93 2.86 2.67 8.81 0.302 0.376 6.76 4.99 4.36 0.30 -0.03 24 23 0.32 0.60 102 18 7.8 0.012 0.68 0.32 0.22 2.54 2.79 7.08 8.81 0.804 0.679 12.23 4.99 5.54 0.31 0.07 23 22 0.01 0.60 62 18 8.1 0.012 0.68 0.33 0.01 2.54 2.72 6.93 8.81 0.786 0.668 12.02 4.99 5.52 0.19 -0.02 22 21 0.15 0.60 25 18 8.3 0.012 0.68 0.48 0.10 2.65 2.69 7.10 8.81 0.806 0.681 12.25 4.99 5.54 0.08 0.02 21 20 0.19 0.60 65 24 8.4 0.012 0.68 0.67 0.13 2.77 2.67 7.41 18.98 0.390 0.434 10.41 6.05 5.67 0.19 0.04 20 19 0.04 0.60 88 24 8.6 0.012 0.68 0.71 0.03 2.80 2.63 7.38 18.98 0.389 0.432 10.38 6.05 5.67 0.26 0.00 19 18 0.01 0.60 30 24 8.8 0.012 0.68 0.72 0.01 2.81 2.58 7.26 18.98 0.382 0.428 10.28 6.05 5.64 0.09 -0.02 18 vault 0.00 1.31 6 24 8.9 0.012 0.68 0.72 0.00 2.81 2.57 7.21 28.04 0.257 0.346 8.30 8.93 7.48 0.01 -0.01 vault 17 0.00 0.60 19 12 6.3 0.012 0.68 0 0.00 0.00 3.19 0.14 2.99 0.047 0.149 1.79 3.81 1.92 0.16 - 17 16 0.00 0.60 60 12 6.5 0.012 0.68 0 0.00 0.00 3.14 0.14 2.99 0.047 0.149 1.79 3.81 1.92 0.52 0.00 16 15 0.00 0.60 55 12 7.0 0.012 0.68 0 0.00 0.00 2.99 0.14 2.99 0.047 0.149 1.79 3.81 1.92 0.48 0.00 15 13 0.00 0.60 80 12 7.5 0.012 0.68 0 0.00 0.00 2.87 0.14 2.99 0.047 0.149 1.79 3.81 1.92 0.69 0.00 14 13 1.71 3.00 6 12 6.3 0.012 0.68 1.71 1.16 1.16 3.19 0.14 6.68 0.021 0.102 1.22 8.52 3.44 0.03 - 13 11 0.00 0.60 122 12 8.2 0.012 0.68 0 0.00 1.16 2.71 3.16 2.99 1.056 0.881 10.57 3.81 4.30 0.47 - 12 11 1.32 6.56 22 12 6.3 0.012 0.68 1.32 0.90 0.90 3.19 2.87 9.88 0.290 0.369 4.42 12.59 10.90 0.03 - 11 10 0.00 0.60 112 12 8.6 0.012 0.68 0 0.00 0.00 2.62 0.00 2.99 0.000 0.033 0.40 3.81 0.80 2.33 -1.00 10 stormfilter 0.00 0.60 42 12 11.0 0.012 0.68 0 0.00 0.00 2.25 0.00 2.99 0.000 0.033 0.40 3.81 0.80 0.88 - stormfilter 7 0.00 0.80 168 12 11.8 0.012 0.68 0 0.00 0.00 2.15 0.00 3.45 0.000 0.033 0.40 4.40 0.92 3.03 - 8 7 0.08 28.73 22 12 6.3 0.012 0.68 0.08 0.05 0.05 3.19 0.17 20.68 0.008 0.061 0.73 26.35 7.73 0.05 0.05 7 6 0.00 0.80 47 12 14.9 0.012 0.68 0 0.00 0.05 1.86 0.10 3.45 0.029 0.119 1.42 4.40 1.96 0.40 -0.42Page 1 22298 kingco - REV.xls 6 5 0.00 0.80 39 12 15.3 0.012 0.68 0 0.00 0.05 1.83 0.10 3.45 0.029 0.118 1.41 4.40 1.96 0.33 -0.02 5 4 0.00 2.99 243 12 15.6 0.012 0.68 0 0.00 0.05 1.80 0.10 6.67 0.015 0.079 0.95 8.50 2.95 1.37 -0.01 4 3 0.00 0.80 33 12 17.0 0.012 0.68 0 0.00 0.05 1.71 0.09 3.45 0.027 0.114 1.37 4.40 1.96 0.28 -0.05 3 1 0.00 0.80 145 12 17.3 0.012 0.68 0 0.00 0.05 1.69 0.09 3.45 0.027 0.113 1.36 4.40 1.96 1.23 -0.01 1 ex. 5 0.00 1.00 50 12 18.5 0.012 0.68 0 0.00 0.05 1.62 0.09 3.86 0.023 0.106 1.27 4.92 2.03 0.41 -0.04 FROM TO A s L d Tc n C SUM A A*C SUM A*C I Qd Qf Qd/Qf D/d D Vf Vd Tt Qr ======================================================================================================================================= Page 2 CATCHMENT AREAS Impervious C=0.90 Pervious C=0.25 Forest C=0.10 Catch Basin No.Impervious Area (SF) Pervious Area (SF) Forested Area (SF) Tributary Area (SF) Tributary Area (AC)Weighted C 7 4,649 24,514 29,163 0.67 0.35 10 6,663 125,215 131,878 3.03 0.28 15 307 0 307 0.01 0.90 16 1,156 785 1,941 0.04 0.64 17 6,102 2,324 8,426 0.19 0.72 18 1,472 166 5,000 6,638 0.15 0.28 19 424 47 471 0.01 0.84 20 10,484 3,618 14,102 0.32 0.73 21 7,652 1,583 4,191 13,426 0.31 0.57 22 8,329 925 9,254 0.21 0.84 23 17,978 9,412 27,390 0.63 0.68 24 22,345 11,059 5,396 38,800 0.89 0.60 25 1,303 145 1,448 0.03 0.84 26 2,742 305 3,047 0.07 0.84 27 3,813 424 4,237 0.10 0.84 28 19,063 8,633 27,696 0.64 0.70 29 17,448 5,148 3,528 26,124 0.60 0.66 30 2,852 317 3,169 0.07 0.84 31 3,825 425 4,250 0.10 0.84 TOTAL 118,258 42,041 13,115 173,414 3.98 0.68 Note: SITE @3.9" CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS AA A N N N N N N N HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E HA R M O N Y R I D G E A-NNNNNNN B. C . E . J O B N O . 2 2 2 9 8 47 NOT F O R CO N S T R U C T I O N PUGET DR SE BASIN MAP 1 SCALE: 1"=50' R O L L I N G H I L L S A V E S E PUG E T D R S E ABE R D E E N A V E S E PUGET DR SE BASIN MAP EX DITCH BASIN EX DITCH BASIN EX DITCH EX DITCH 1 WWHM2012 PROJECT REPORT Puget Dr SE Ditch Basin 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 2 General Model Information WWHM2012 Project Name:22298-WWHM-Puget Dr Site Name:Harmony Ridge Site Address: City: Report Date:3/11/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 3 Landuse Basin Data Predeveloped Land Use Puget Dr Ditch Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.42 C, Lawn, Flat 0.68 Pervious Total 2.1 Impervious Land Use acre ROADS FLAT 0.32 Impervious Total 0.32 Basin Total 2.42 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 4 Mitigated Land Use Puget Dr Ditch Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.52 C, Lawn, Flat 0.68 Pervious Total 2.2 Impervious Land Use acre ROADS FLAT 0.32 Impervious Total 0.32 Basin Total 2.52 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 5 Routing Elements Predeveloped Routing 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 6 Mitigated Routing 22298-WWHM-Puget Dr 3/11/2025 2:48:04 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:2.1 Total Impervious Area:0.32 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.2 Total Impervious Area:0.32 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.195133 5 year 0.279582 10 year 0.341438 25 year 0.426446 50 year 0.494826 100 year 0.567609 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.197123 5 year 0.282849 10 year 0.34571 25 year 0.432172 50 year 0.501775 100 year 0.575903 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.297 0.300 1950 0.305 0.308 1951 0.210 0.215 1952 0.128 0.130 1953 0.108 0.110 1954 0.158 0.159 1955 0.175 0.179 1956 0.165 0.168 1957 0.225 0.228 1958 0.137 0.138 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 8 1959 0.119 0.121 1960 0.230 0.234 1961 0.181 0.182 1962 0.109 0.109 1963 0.172 0.174 1964 0.158 0.161 1965 0.224 0.226 1966 0.133 0.135 1967 0.311 0.315 1968 0.229 0.229 1969 0.189 0.190 1970 0.180 0.181 1971 0.212 0.214 1972 0.279 0.281 1973 0.120 0.121 1974 0.200 0.201 1975 0.242 0.245 1976 0.174 0.176 1977 0.135 0.136 1978 0.167 0.168 1979 0.186 0.186 1980 0.344 0.348 1981 0.176 0.177 1982 0.341 0.345 1983 0.171 0.171 1984 0.139 0.140 1985 0.171 0.171 1986 0.219 0.223 1987 0.214 0.219 1988 0.103 0.103 1989 0.129 0.129 1990 0.607 0.616 1991 0.405 0.410 1992 0.152 0.154 1993 0.106 0.108 1994 0.086 0.086 1995 0.155 0.157 1996 0.314 0.320 1997 0.232 0.236 1998 0.162 0.163 1999 0.412 0.417 2000 0.191 0.193 2001 0.146 0.147 2002 0.269 0.270 2003 0.245 0.248 2004 0.348 0.348 2005 0.201 0.204 2006 0.193 0.196 2007 0.528 0.534 2008 0.397 0.403 2009 0.260 0.265 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.6069 0.6163 2 0.5275 0.5344 3 0.4120 0.4174 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 9 4 0.4051 0.4101 5 0.3968 0.4026 6 0.3476 0.3484 7 0.3438 0.3479 8 0.3412 0.3447 9 0.3135 0.3204 10 0.3112 0.3149 11 0.3047 0.3081 12 0.2971 0.2999 13 0.2789 0.2810 14 0.2695 0.2703 15 0.2604 0.2648 16 0.2450 0.2481 17 0.2419 0.2452 18 0.2324 0.2358 19 0.2295 0.2339 20 0.2287 0.2287 21 0.2254 0.2278 22 0.2242 0.2257 23 0.2187 0.2230 24 0.2142 0.2187 25 0.2115 0.2150 26 0.2100 0.2137 27 0.2009 0.2038 28 0.2001 0.2013 29 0.1929 0.1959 30 0.1914 0.1929 31 0.1892 0.1896 32 0.1863 0.1863 33 0.1807 0.1825 34 0.1798 0.1815 35 0.1762 0.1788 36 0.1753 0.1769 37 0.1739 0.1761 38 0.1721 0.1737 39 0.1712 0.1712 40 0.1706 0.1706 41 0.1673 0.1682 42 0.1650 0.1678 43 0.1619 0.1632 44 0.1583 0.1611 45 0.1579 0.1595 46 0.1550 0.1570 47 0.1521 0.1543 48 0.1465 0.1465 49 0.1385 0.1395 50 0.1369 0.1378 51 0.1355 0.1357 52 0.1332 0.1348 53 0.1293 0.1298 54 0.1279 0.1293 55 0.1196 0.1212 56 0.1190 0.1211 57 0.1086 0.1096 58 0.1085 0.1087 59 0.1057 0.1078 60 0.1034 0.1034 61 0.0862 0.0862 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 10 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 11 Duration Flows The Development Failed :duration increase for more than 50% of the flows. Flow(cfs)Predev Mit Percentage Pass/Fail 0.0976 3012 3260 108 Fail 0.1016 2648 2879 108 Fail 0.1056 2325 2524 108 Fail 0.1096 2072 2233 107 Fail 0.1136 1823 1987 108 Fail 0.1176 1604 1760 109 Fail 0.1216 1431 1554 108 Fail 0.1257 1268 1396 110 Fail 0.1297 1133 1228 108 Fail 0.1337 1006 1116 110 Fail 0.1377 906 990 109 Fail 0.1417 817 899 110 Fail 0.1457 726 806 111 Fail 0.1497 649 713 109 Fail 0.1537 570 643 112 Fail 0.1578 518 560 108 Fail 0.1618 470 508 108 Fail 0.1658 419 462 110 Fail 0.1698 374 418 111 Fail 0.1738 333 368 110 Fail 0.1778 295 327 110 Fail 0.1818 270 303 112 Fail 0.1858 251 277 110 Fail 0.1899 239 252 105 Fail 0.1939 206 231 112 Fail 0.1979 192 208 108 Pass 0.2019 174 193 110 Pass 0.2059 162 172 106 Pass 0.2099 152 163 107 Pass 0.2139 141 152 107 Pass 0.2179 133 141 106 Pass 0.2220 125 135 108 Pass 0.2260 113 122 107 Pass 0.2300 104 111 106 Pass 0.2340 98 104 106 Pass 0.2380 94 96 102 Pass 0.2420 84 94 111 Fail 0.2460 76 84 110 Pass 0.2500 73 76 104 Pass 0.2541 69 74 107 Pass 0.2581 65 68 104 Pass 0.2621 61 66 108 Pass 0.2661 59 60 101 Pass 0.2701 55 58 105 Pass 0.2741 51 55 107 Pass 0.2781 48 50 104 Pass 0.2822 45 47 104 Pass 0.2862 42 45 107 Pass 0.2902 40 42 104 Pass 0.2942 38 40 105 Pass 0.2982 36 38 105 Pass 0.3022 34 36 105 Pass 0.3062 31 35 112 Fail 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 12 0.3102 31 31 100 Pass 0.3143 29 31 106 Pass 0.3183 28 29 103 Pass 0.3223 27 27 100 Pass 0.3263 25 27 108 Pass 0.3303 24 25 104 Pass 0.3343 21 24 114 Fail 0.3383 19 19 100 Pass 0.3423 17 19 111 Fail 0.3464 16 18 112 Fail 0.3504 15 15 100 Pass 0.3544 14 14 100 Pass 0.3584 14 14 100 Pass 0.3624 13 14 107 Pass 0.3664 12 13 108 Pass 0.3704 12 12 100 Pass 0.3744 12 12 100 Pass 0.3785 12 12 100 Pass 0.3825 10 11 110 Pass 0.3865 10 10 100 Pass 0.3905 10 10 100 Pass 0.3945 8 10 125 Fail 0.3985 7 10 142 Fail 0.4025 7 8 114 Fail 0.4065 5 7 140 Fail 0.4106 5 7 140 Fail 0.4146 4 5 125 Fail 0.4186 4 4 100 Pass 0.4226 4 4 100 Pass 0.4266 4 4 100 Pass 0.4306 4 4 100 Pass 0.4346 3 4 133 Fail 0.4386 3 4 133 Fail 0.4427 3 3 100 Pass 0.4467 3 3 100 Pass 0.4507 2 3 150 Fail 0.4547 2 2 100 Pass 0.4587 2 2 100 Pass 0.4627 2 2 100 Pass 0.4667 2 2 100 Pass 0.4707 2 2 100 Pass 0.4748 2 2 100 Pass 0.4788 2 2 100 Pass 0.4828 2 2 100 Pass 0.4868 2 2 100 Pass 0.4908 2 2 100 Pass 0.4948 2 2 100 Pass 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. 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.024 acre-feet On-line facility target flow:0.0243 cfs. Adjusted for 15 min:0.0243 cfs. Off-line facility target flow:0.0135 cfs. Adjusted for 15 min:0.0135 cfs. 22298-WWHM-Puget Dr 3/11/2025 2:48:27 PM Page 14 LID Report 22298-WWHM-Puget Dr 3/11/2025 2:48:34 PM Page 15 POC 2 POC #2 was not reported because POC must exist in both scenarios and both scenarios must have been run. 22298-WWHM-Puget Dr 3/11/2025 2:48:34 PM Page 16 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. 22298-WWHM-Puget Dr 3/11/2025 2:48:34 PM Page 17 Appendix Predeveloped Schematic 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 18 Mitigated Schematic 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 19 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 22298-WWHM-Puget Dr.wdm MESSU 25 Pre22298-WWHM-Puget Dr.MES 27 Pre22298-WWHM-Puget Dr.L61 28 Pre22298-WWHM-Puget Dr.L62 30 POC22298-WWHM-Puget Dr1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Puget Dr Ditch MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 20 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 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 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 21 <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# *** Puget Dr Ditch*** PERLND 10 1.42 COPY 501 12 PERLND 10 1.42 COPY 501 13 PERLND 16 0.68 COPY 501 12 PERLND 16 0.68 COPY 501 13 IMPLND 1 0.32 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 22 <------><--------><--------><--------><--------><--------><--------> *** 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 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 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 23 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 22298-WWHM-Puget Dr.wdm MESSU 25 Mit22298-WWHM-Puget Dr.MES 27 Mit22298-WWHM-Puget Dr.L61 28 Mit22298-WWHM-Puget Dr.L62 30 POC22298-WWHM-Puget Dr1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Puget Dr Ditch MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 24 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 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 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 25 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Puget Dr Ditch*** PERLND 10 1.52 COPY 501 12 PERLND 10 1.52 COPY 501 13 PERLND 16 0.68 COPY 501 12 PERLND 16 0.68 COPY 501 13 IMPLND 1 0.32 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 26 <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 27 Predeveloped HSPF Message File 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 28 Mitigated HSPF Message File 22298-WWHM-Puget Dr 3/11/2025 2:48:35 PM Page 29 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com CB#26 CB#27 CB#28CB#33 CB#32 CB#31 CB#21 CB#20 CB#19 CB#18 CB#1 CB#3 CB#4 CB#5 CB#6 CB#10 CB#14 CB#15 CB#17 CB#16 CB#35 EX CB#1 CB#34 EX CB#5 CB#2 CB#9 CB#13 CB#29 CB#30 CB#23CB#22 CB#24 CB#25 CB#11 CB#12 CB#7 CB#8 CITY OF RENTON, KING COUNTY, WASHINGTON HARMONY RIDGE A PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M. FOR IN COMPLIANCE WITH CITY OF RENTON STANDARDS HARMONY RIDGEICHIJO USA, CO., LTD1406 140TH PL SE, SUITE 104, BELLEVUE, WA 98007 HA R M O N Y R I D G E LU A 2 3 - 0 0 0 1 4 3 C2 5 0 0 2 2 7 2 HA R M O N Y R I D G E PR 2 3 - 0 0 0 0 7 6 B. C . E . J O B N O . 2 2 2 9 8 66 T R E N T ON SK O D A DATUM BENCHMARK CALL BEFORE YOU DIG: 1-800-424-5555 CONVEYANCE ANALYSIS MAP 1 SCALE: 1"=50' 1 2 3 4 5 6 11 10 9 8 7 17 16 15 14 13 12 18 19 20 TRACT D TRACT C TRACT B TRACT A ROAD A RO A D B ALLEY Z 11 6 T H A V E S E R O L L I N G H I L L S A V E S E PUG E T D R S E CA M A S C I R S E SE 1 9 T H S T S E 1 9 T H S T ABE R D E E N A V E S E CONVEYANCE ANALYSIS MAP DEVELOPED BASIN 2 BYPASS BASIN BYPASS BASIN EX BUILDING UPSTREAM BASIN 1 STORMFILTER RUN #1 RUN #2 RUN #3 Figure 5.0.2 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:Harmony Ridge Run#1.bwp Surcharge condition at intermediate junctions Tailwater Elevation:447.3 feet Discharge Range:7.21 to 7.21 Step of 0.1 [cfs] Overflow Elevation:453.46 feet Weir:NONE Channel Width:1.5 feet PIPE NO. 1: 6 LF - 24"CP @ 1.33% OUTLET: 440.90 INLET: 440.98 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 451.03 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 7.21 6.48 447.46 * 0.012 0.96 0.69 6.40 6.40 6.33 6.48 1.39 PIPE NO. 2: 30 LF - 24"CP @ 0.60% OUTLET: 440.98 INLET: 441.16 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 449.75 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 7.21 6.48 447.64 * 0.012 0.96 0.86 6.48 6.48 6.33 6.48 1.40 PIPE NO. 3: 88 LF - 24"CP @ 0.60% OUTLET: 441.16 INLET: 441.69 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 451.03 BEND: 45 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 7.21 6.10 447.79 * 0.012 0.96 0.86 6.48 6.48 6.03 6.10 1.32 PIPE NO. 4: 65 LF - 24"CP @ 0.60% OUTLET: 441.69 INLET: 442.08 INTYP: 5 VAULT-CB#18 CB#18-CB#19 CB#19-CB#20 CB#20-CB#21 RUN #1 JUNC NO. 4: OVERFLOW-EL: 455.35 BEND: 45 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.04 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 7.21 5.77 447.85 * 0.012 0.96 0.86 6.10 6.10 5.77 5.75 1.23 PIPE NO. 5: 62 LF - 18"CP @ 0.60% OUTLET: 442.23 INLET: 442.60 INTYP: 5 JUNC NO. 5: OVERFLOW-EL: 455.83 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.02 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 6.93 5.85 448.45 * 0.012 1.02 1.01 5.62 5.62 5.49 5.85 1.62 PIPE NO. 6: 25 LF - 18"CP @ 0.60% OUTLET: 442.08 INLET: 442.23 INTYP: 5 JUNC NO. 6: OVERFLOW-EL: 455.41 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.02 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 6.80 6.73 448.96 * 0.012 1.01 0.99 6.37 6.37 6.31 6.73 1.67 PIPE NO. 7: 102 LF - 18"CP @ 0.60% OUTLET: 442.60 INLET: 443.21 INTYP: 5 JUNC NO. 7: OVERFLOW-EL: 456.09 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.07 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 6.66 6.25 449.46 * 0.012 1.00 0.98 6.36 6.36 6.10 6.25 1.40 PIPE NO. 8: 113 LF - 18"CP @ 3.02% OUTLET: 443.71 INLET: 447.12 INTYP: 5 JUNC NO. 8: OVERFLOW-EL: 454.57 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.15 CB#21-CB#22 CB#22-CB#23 CB#23-CB#24 CB#24-CB#25 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 6.23 3.04 450.16 * 0.012 0.97 0.58 5.75 5.75 2.69 3.04 1.55 PIPE NO. 9: 25 LF - 18"CP @ 1.00% OUTLET: 447.12 INLET: 447.37 INTYP: 5 JUNC NO. 9: OVERFLOW-EL: 454.57 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.08 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 5.42 2.96 450.33 * 0.012 0.90 0.73 3.04 3.04 2.86 2.96 1.24 PIPE NO.10: 169 LF - 18"CP @ 1.30% OUTLET: 447.37 INLET: 449.56 INTYP: 5 JUNC NO.10: OVERFLOW-EL: 456.03 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.38 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 5.01 1.16 450.72 * 0.012 0.87 0.65 2.96 2.96 1.08 1.16 1.05 PIPE NO.11: 150 LF - 12"CP @ 0.60% OUTLET: 449.56 INLET: 450.46 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 3.63 2.06 452.52 * 0.012 0.82 1.00 1.16 1.16 1.59 2.06 1.49 CB#25-CB#26 CB#26-CB#27 CB#27-CB#28 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:Harmony Ridge Run#2.bwp Surcharge condition at intermediate junctions Tailwater Elevation:449.46 feet Discharge Range:2.86 to 2.86 Step of 0.1 [cfs] Overflow Elevation:450.14 feet Weir:NONE Channel Width:1.5 feet PIPE NO. 1: 77 LF - 18"CP @ 1.26% OUTLET: 443.21 INLET: 444.18 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 454.57 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 2.86 5.35 449.53 * 0.012 0.65 0.49 6.25 6.25 5.33 5.35 0.86 PIPE NO. 2: 160 LF - 18"CP @ 0.60% OUTLET: 444.18 INLET: 445.14 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 452.16 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.07 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 2.86 4.57 449.71 * 0.012 0.65 0.59 5.35 5.35 4.50 4.57 0.92 PIPE NO. 3: 24 LF - 18"CP @ 0.58% OUTLET: 445.14 INLET: 445.28 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 452.16 BEND: 45 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.49 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 2.67 4.48 449.76 * 0.012 0.63 0.58 4.57 4.57 4.45 4.48 0.85 PIPE NO. 4: 111 LF - 12"CP @ 0.59% OUTLET: 445.78 INLET: 446.44 INTYP: 5 CB#24-CB#29 RUN #2 CB#29-CB#31 CB#31-CB#32 CB#32-CB#33 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 1.79 3.69 450.13 * 0.012 0.58 0.56 3.98 3.98 3.57 3.69 0.85 BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:Harmony Ridge #3.bwp Surcharge condition at intermediate junctions Tailwater Elevation:422.2 feet Discharge Range:0.09 to 0.09 Step of 0.1 [cfs] Overflow Elevation:450.36 feet Weir:NONE Channel Width:1.5 feet PIPE NO. 1: 50 LF - 12"CP @ 1.00% OUTLET: 414.32 INLET: 414.82 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 422.20 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 7.39 422.21 * 0.012 0.13 0.11 7.88 7.88 7.39 7.39 0.16 PIPE NO. 2: 145 LF - 12"CP @ 0.80% OUTLET: 414.82 INLET: 415.98 INTYP: 5 JUNC NO. 2: OVERFLOW-EL: 429.07 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 6.24 422.22 * 0.012 0.13 0.12 7.39 7.39 6.24 6.24 0.16 PIPE NO. 3: 33 LF - 12"CP @ 0.82% OUTLET: 415.98 INLET: 416.25 INTYP: 5 JUNC NO. 3: OVERFLOW-EL: 428.56 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 5.98 422.23 * 0.012 0.13 0.12 6.24 6.24 5.98 5.98 0.16 PIPE NO. 4: 243 LF - 12"CP @ 2.99% OUTLET: 416.25 INLET: 423.52 INTYP: 5 EX. CB#5-CB#1 RUN #3 CB#1-CB#3 CB#3-CB#4 CB#4-CB#5 JUNC NO. 4: OVERFLOW-EL: 439.87 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.15 423.67 * 0.012 0.13 0.09 5.98 5.98 0.13 ***** 0.15 PIPE NO. 5: 39 LF - 12"CP @ 0.82% OUTLET: 423.52 INLET: 423.84 INTYP: 5 JUNC NO. 5: OVERFLOW-EL: 439.79 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 424.00 * 0.012 0.13 0.12 0.15 0.15 0.13 ***** 0.16 PIPE NO. 6: 40 LF - 12"CP @ 0.80% OUTLET: 423.84 INLET: 424.16 INTYP: 5 JUNC NO. 6: OVERFLOW-EL: 439.36 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 424.32 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO. 7: 168 LF - 12"CP @ 0.80% OUTLET: 424.16 INLET: 425.50 INTYP: 5 JUNC NO. 7: OVERFLOW-EL: 434.71 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 425.66 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO. 8: 42 LF - 12"CP @ *****% OUTLET: 428.55 INLET: 418.80 INTYP: 5 JUNC NO. 8: OVERFLOW-EL: 435.52 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 CB#5-CB#6 CB#6-CB#7 CB#7-STORMFILTER STORMFILTER-CB#10 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 10.01 428.81 * 0.012 0.13 0.00 0.00 0.13 10.01 10.01 0.28 PIPE NO. 9: 112 LF - 12"CP @ 0.61% OUTLET: 428.80 INLET: 429.48 INTYP: 5 JUNC NO. 9: OVERFLOW-EL: 439.36 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 429.64 * 0.012 0.13 0.12 0.01 0.12 0.13 ***** 0.16 PIPE NO.10: 122 LF - 12"CP @ 0.60% OUTLET: 429.48 INLET: 430.21 INTYP: 5 JUNC NO.10: OVERFLOW-EL: 433.98 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 430.37 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO.11: 80 LF - 12"CP @ 0.60% OUTLET: 430.21 INLET: 430.69 INTYP: 5 JUNC NO.11: OVERFLOW-EL: 439.96 BEND: 45 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 430.85 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO.12: 55 LF - 12"CP @ 0.60% OUTLET: 430.69 INLET: 431.02 INTYP: 5 JUNC NO.12: OVERFLOW-EL: 447.73 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 CB#10-CB#11 CB#11-CB#13 CB#13-CB#15 CB#15-CB#16 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 431.18 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO.13: 60 LF - 12"CP @ 0.60% OUTLET: 431.02 INLET: 431.38 INTYP: 5 JUNC NO.13: OVERFLOW-EL: 450.06 BEND: 90 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 431.54 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 PIPE NO.14: 19 LF - 12"CP @ 0.63% OUTLET: 431.38 INLET: 431.50 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI ************************************************************************** ***** 0.09 0.16 431.66 * 0.012 0.13 0.12 0.16 0.16 0.13 ***** 0.16 CB#16-CB#17 CB#17-VAULT Section 6.0 22298.001-DRNG 6.0 SPECIAL REPORTS AND STUDIES 6.1 Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. updated July 3, 2023 6.2 Final Tree Protection Plan prepared by Washington Forestry Consultants, Inc. dated August 21, 2025 Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. updated July 3, 2023 6.1 EarthSolutionsNWLLC EarthSolutionsNWLLC Geotechnical Engineering Construction Observation/Testing Environmental Services 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 –116TH AVENUE SOUTHEAST RENTON,WASHINGTON ES-8888 PREPARED FOR ICHIJO USA CO., LTD. November 21, 2022 Updated July 3, 2023 _________________________ Samuel E. Suruda, L.G. Senior Staff Geologist _________________________ Chase G. Halsen, L.G., L.E.G. Senior Project Geologist _________________________ Keven D. Hoffmann, P.E. Associate Principal Engineer GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 – 116TH AVENUE SOUTHEAST RENTON, WASHINGTON ES-8888 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 07/03/2023 07/03/2023 Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this ReportGeotechnical-engineering services typically include the planning, collection, interpretation, and analysis of exploratory data from widely spaced borings and/or test pits. Field data are combined with results from laboratory tests of soil and rock samples obtained from field exploration (if applicable), observations made during site reconnaissance, and historical information to form one or more models of the expected subsurface conditions beneath the site. Local geology and alterations of the site surface and subsurface by previous and proposed construction are also important considerations. Geotechnical engineers apply their engineering training, experience, and judgment to adapt the requirements of the prospective project to the subsurface model(s). Estimates are made of the subsurface conditions that will likely be exposed during construction as well as the expected performance of foundations and other structures being planned and/or affected by construction activities. The culmination of these geotechnical-engineering services is typically a geotechnical-engineering report providing the data obtained, a discussion of the subsurface model(s), the engineering and geologic engineering assessments and analyses made, and the recommendations developed to satisfy the given requirements of the project. These reports may be titled investigations, explorations, studies, assessments, or evaluations. Regardless of the title used, the geotechnical-engineering report is an engineering interpretation of the subsurface conditions within the context of the project and does not represent a close examination, systematic inquiry, or thorough investigation of all site and subsurface conditions. Geotechnical-Engineering Services are Performed for Specific Purposes, Persons, and Projects, and At Specific TimesGeotechnical engineers structure their services to meet the specific needs, goals, and risk management preferences of their clients. A geotechnical-engineering study conducted for a given civil engineer will not likely meet the needs of a civil-works constructor or even a different civil engineer. Because each geotechnical-engineering study is unique, each geotechnical-engineering report is unique, prepared solely for the client. Likewise, geotechnical-engineering services are performed for a specific project and purpose. For example, it is unlikely that a geotechnical- engineering study for a refrigerated warehouse will be the same as one prepared for a parking garage; and a few borings drilled during a preliminary study to evaluate site feasibility will not be adequate to develop geotechnical design recommendations for the project. Do not rely on this report if your geotechnical engineer prepared it: • for a different client; • for a different project or purpose; • for a different site (that may or may not include all or a portion of the original site); or • before important events occurred at the site or adjacent to it; e.g., man-made events like construction or environmental remediation, or natural events like floods, droughts, earthquakes, or groundwater fluctuations. Note, too, the reliability of a geotechnical-engineering report can be affected by the passage of time, because of factors like changed subsurface conditions; new or modified codes, standards, or regulations; or new techniques or tools. If you are the least bit uncertain about the continued reliability of this report, contact your geotechnical engineer before applying the recommendations in it. A minor amount of additional testing or analysis after the passage of time – if any is required at all – could prevent major problems. Read this Report in Full Costly problems have occurred because those relying on a geotechnical- engineering report did not read the report in its entirety. Do not rely on an executive summary. Do not read selective elements only. Read and refer to the report in full. You Need to Inform Your Geotechnical Engineer About Change Your geotechnical engineer considered unique, project-specific factors when developing the scope of study behind this report and developing the confirmation-dependent recommendations the report conveys. Typical changes that could erode the reliability of this report include those that affect: • the site’s size or shape; • the elevation, configuration, location, orientation, function or weight of the proposed structure and the desired performance criteria; • the composition of the design team; or • project ownership. As a general rule, always inform your geotechnical engineer of project or site changes – even minor ones – and request an assessment of their impact. The geotechnical engineer who prepared this report cannot accept responsibility or liability for problems that arise because the geotechnical engineer was not informed about developments the engineer otherwise would have considered. Most of the “Findings” Related in This Report Are Professional Opinions Before construction begins, geotechnical engineers explore a site’s subsurface using various sampling and testing procedures. Geotechnical engineers can observe actual subsurface conditions only at those specific locations where sampling and testing is performed. The data derived from that sampling and testing were reviewed by your geotechnical engineer, who then applied professional judgement to form opinions about subsurface conditions throughout the site. Actual sitewide-subsurface conditions may differ – maybe significantly – from those indicated in this report. Confront that risk by retaining your geotechnical engineer to serve on the design team through project completion to obtain informed guidance quickly, whenever needed. This Report’s Recommendations Are Confirmation-Dependent The recommendations included in this report – including any options or alternatives – are confirmation-dependent. In other words, they are not final, because the geotechnical engineer who developed them relied heavily on judgement and opinion to do so. Your geotechnical engineer can finalize the recommendations only after observing actual subsurface conditions exposed during construction. If through observation your geotechnical engineer confirms that the conditions assumed to exist actually do exist, the recommendations can be relied upon, assuming no other changes have occurred. The geotechnical engineer who prepared this report cannot assume responsibility or liability for confirmation-dependent recommendations if you fail to retain that engineer to perform construction observation. This Report Could Be Misinterpreted Other design professionals’ misinterpretation of geotechnical- engineering reports has resulted in costly problems. Confront that risk by having your geotechnical engineer serve as a continuing member of the design team, to: • confer with other design-team members; • help develop specifications; • review pertinent elements of other design professionals’ plans and specifications; and • be available whenever geotechnical-engineering guidance is needed. You should also confront the risk of constructors misinterpreting this report. Do so by retaining your geotechnical engineer to participate in prebid and preconstruction conferences and to perform construction-phase observations. Give Constructors a Complete Report and GuidanceSome owners and design professionals mistakenly believe they can shift unanticipated-subsurface-conditions liability to constructors by limiting the information they provide for bid preparation. To help prevent the costly, contentious problems this practice has caused, include the complete geotechnical-engineering report, along with any attachments or appendices, with your contract documents, but be certain to note conspicuously that you’ve included the material for information purposes only. To avoid misunderstanding, you may also want to note that “informational purposes” means constructors have no right to rely on the interpretations, opinions, conclusions, or recommendations in the report. Be certain that constructors know they may learn about specific project requirements, including options selected from the report, only from the design drawings and specifications. Remind constructors that they may perform their own studies if they want to, and be sure to allow enough time to permit them to do so. Only then might you be in a position to give constructors the information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Conducting prebid and preconstruction conferences can also be valuable in this respect. Read Responsibility Provisions Closely Some client representatives, design professionals, and constructors do not realize that geotechnical engineering is far less exact than other engineering disciplines. This happens in part because soil and rock on project sites are typically heterogeneous and not manufactured materials with well-defined engineering properties like steel and concrete. That lack of understanding has nurtured unrealistic expectations that have resulted in disappointments, delays, cost overruns, claims, and disputes. To confront that risk, geotechnical engineers commonly include explanatory provisions in their reports. Sometimes labeled “limitations,” many of these provisions indicate where geotechnical engineers’ responsibilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The personnel, equipment, and techniques used to perform an environmental study – e.g., a “phase-one” or “phase-two” environmental site assessment – differ significantly from those used to perform a geotechnical-engineering study. For that reason, a geotechnical-engineering report does not usually provide environmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated subsurface environmental problems have led to project failures. If you have not obtained your own environmental information about the project site, ask your geotechnical consultant for a recommendation on how to find environmental risk-management guidance. Obtain Professional Assistance to Deal with Moisture Infiltration and Mold While your geotechnical engineer may have addressed groundwater, water infiltration, or similar issues in this report, the engineer’s services were not designed, conducted, or intended to prevent migration of moisture – including water vapor – from the soil through building slabs and walls and into the building interior, where it can cause mold growth and material-performance deficiencies. Accordingly, proper implementation of the geotechnical engineer’s recommendations will not of itself be sufficient to prevent moisture infiltration. Confront the risk of moisture infiltration by including building-envelope or mold specialists on the design team. Geotechnical engineers are not building-envelope or mold specialists. Copyright 2019 by Geoprofessional Business Association (GBA). Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with GBA’s specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission of GBA, and only for purposes of scholarly research or book review. Only members of GBA may use this document or its wording as a complement to or as an element of a report of any kind. Any other firm, individual, or other entity that so uses this document without being a GBA member could be committing negligent or intentional (fraudulent) misrepresentation. Telephone: 301/565-2733 e-mail: info@geoprofessional.org www.geoprofessional.org 15365 N.E. 90th Street, Suite 100 • Redmond, WA 98052 • (425) 449-4704 • FAX (425) 449-4711 Earth Solutions NW LLC Geotechnical Engineering, Construction Observation/Testing and Environmental Services November 21, 2022 Updated July 3, 2023 ES-8888 Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Kanon Kupferer Greetings, Kanon: Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical report to support the proposed project. Based on the results of our investigation, the construction of a residential development is feasible from a geotechnical standpoint. Our study indicates the site is underlain by ground moraine deposits (glacial till) that consist primarily of silty sand with gravel, with an isolated area of near-surface fill. Groundwater was not exposed at the test pit locations during the October 2022 exploration. Based on our findings, the proposed single-family residences may be constructed on conventional continuous and spread footing foundations that bear directly on competent native soil, recompacted native soil, or new structural fill that is placed and compacted directly on competent native soil. Native soil conditions considered suitable for support of the proposed structures will likely be encountered beginning at a depth of about two feet below existing grades across most of the property. Areas of existing fill will need to be removed or reworked to establish suitable bearing conditions in proposed structural areas, as recommended by ESNW at the time of construction. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. From a geotechnical standpoint, full infiltration designs are not recommended for the project due to the widespread prevalence of glacially consolidated soils. The dense to very dense nature of these deposits, in addition to areas of appreciable fine contents, are the primary bases for this opinion. Further discussion of infiltration feasibility is provided within this report. Pertinent geotechnical recommendations are provided in this study. We appreciate the opportunity to be of service to you on this project. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Chase G. Halsen, L.G., L.E.G. Senior Project Geologist Earth Solutions NW, LLC Table of Contents ES-8888 PAGE INTRODUCTION ................................................................................. 1 General .................................................................................... 1 Project Description ................................................................. 2 SITE CONDITIONS ............................................................................. 2 Surface ..................................................................................... 2 Subsurface .............................................................................. 2 Topsoil and Fill ............................................................. 3 Native Soil and Geologic Setting ................................ 3 Groundwater ................................................................. 3 Geologically Hazardous Areas .............................................. 4 Erosion Hazard ............................................................. 4 Coal Mine Hazard ......................................................... 4 Steep Slopes ................................................................. 5 DISCUSSION AND RECOMMENDATIONS ....................................... 5 General .................................................................................... 5 Site Preparation and Earthwork ............................................. 6 Temporary Erosion Control ......................................... 6 Stripping ....................................................................... 6 Excavations and Slopes .............................................. 7 In-situ and Imported Soil ............................................. 7 Subgrade Preparation .................................................. 8 Structural Fill ................................................................ 8 Foundations ............................................................................ 8 Seismic Design ....................................................................... 9 Slab-on-Grade Floors ............................................................. 10 Retaining Walls ....................................................................... 10 Drainage................................................................................... 11 Infiltration Feasibility ................................................... 11 Preliminary Detention Vault Design ............................ 12 Preliminary Pavement Sections ............................................. 13 Utility Support and Trench Backfill ....................................... 14 LIMITATIONS ...................................................................................... 14 Additional Services ................................................................. 14 Earth Solutions NW, LLC Table of Contents Cont’d ES-8888 GRAPHICS Plate 1 Vicinity Map Plate 2 Test Pit Location Plan Plate 3 Retaining Wall Drainage Detail Plate 4 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Test Pit Logs Appendix B Laboratory Test Results Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY HARMONY RIDGE 15509 – 116TH AVENUE SOUTHEAST RENTON, WASHINGTON ES-8888 INTRODUCTION General This geotechnical engineering study was prepared for the proposed residential development to be constructed at the United Christian Church campus in Renton, Washington. This study was prepared to provide geotechnical recommendations for currently proposed development plans and included the following geotechnical services:  Test pits to characterize soil and groundwater conditions.  Laboratory testing of representative soil samples collected at the test pit locations.  Geotechnical engineering analyses. The following documents and maps were reviewed as part of the preparation of this study:  Web Soil Survey (WSS), maintained by the Natural Resources Conservation Service under the United States Department of Agriculture (USDA).  Preliminary Utility Map for Harmony Ridge, prepared by Barghausen Consulting Engineers, Inc., dated June 15, 2023.  Geologic Map of the Renton Quadrangle, King County, Washington, prepared by D.R. Mullineaux, 1965.  Soil Survey of the King County Area, Washington, prepared by Dale E. Snyder, Philip S. Gale, and Russell F. Pringle, in association with the USDA SCS, November 1973.  Map of the Seattle Electric Co.’s Renton Coal Mine, Map ID K31, 1919.  Mine Workings from George Watkins Evans’ Report for Renton Coal Company, Map ID K32, 1920.  COR Maps (City of Renton GIS database). Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 2 Updated July 3, 2023 Earth Solutions NW, LLC Project Description The proposed project is currently pursuing construction of 20 single-family residences and associated infrastructure improvements, which will be targeted to the central and southern site areas. The existing church and associated improvements located within the northeast site corner are to remain. Site ingress and egress will be provided via the west edge of 116th Avenue Southeast, with a future potential road extension to the west. Stormwater management is currently proposed via detention within the southwest site corner (Tract A). At the time of report submission, specific building load plans were not available for review; however, based on our experience with similar developments, the proposed residential structures will likely be two stories and constructed using relatively lightly loaded wood framing supported on conventional foundations. Perimeter footing loads will likely be about 2 to 3 kips per lineal foot. Slab-on-grade loading is anticipated to be approximately 150 pounds per square foot (psf). Grade cuts and/or fills of up to about five feet are expected to achieve the design elevation of most lots. More extensive earthwork operations will likely be required to install site utilities and construct the stormwater facility. We understand that a sewer connection will be provided through an easement via the parcel to the northwest of the subject property. If the above design assumptions either change or are incorrect, ESNW should be contacted to review the recommendations provided in this report. ESNW should review the final designs to confirm that appropriate geotechnical recommendations have been incorporated into the plans. SITE CONDITIONS Surface The subject site is located southwest of the intersection between Southeast 16th Street and 116th Avenue Southeast, in Renton, Washington. The approximate site location is depicted on Plate 1 (Vicinity Map) and consists of King County parcel number 202305-9067, totaling a gross site area of about 6.23 acres. The northeast site corner is currently developed with a church and associated improvements. The remaining portions of the site are surfaced with trees and an understory of brush and brambles. Topography generally descends to the south and southwest, with about 25 feet of elevation change occurring within the property confines. Subsurface An ESNW representative observed, logged, and sampled the excavation of 12 test pits within readily accessible areas of the site on October 17, 2022. The test pits ranged in depths from about 8 to 14 feet below the existing ground surface (bgs) and were excavated using a trackhoe and operator retained by ESNW. The approximate locations of the test pits are depicted on Plate 2 (Test Pit Location Plan). Please refer to the test pit logs provided in Appendix A for a more detailed description of the encountered subsurface conditions. Representative soil samples collected at the exploration locations were analyzed following the Unified Soil Classification System (USCS) and USDA methods and procedures. Samples were analyzed in our laboratory for moisture content and grain size distribution in general accordance with ASTM procedures. Laboratory test results are provided in Appendix B. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 3 Updated July 3, 2023 Earth Solutions NW, LLC Topsoil and Fill Topsoil was encountered in approximately the upper 6 to 12 inches of existing grades at the test pit locations. The topsoil was characterized by a dark brown color, the presence of fine organic material, and small root intrusions. Based on our observations, an average topsoil thickness of about six inches was encountered at the test locations during the field exploration. Silty sand with gravel fill soil was exposed at TP-4 and observed extending to a depth of about five feet bgs. The fill was characterized by a dense and damp condition at the time of the field exploration. Fill was not encountered at any of the other test pit locations during the October 2022 fieldwork. Native Soil and Geologic Setting Underlying topsoil, native soils were classified primarily as silty sand with gravel (USCS: SM), consistent with local geologic mapping designations of ground moraine deposits (Qgt), otherwise known as glacial till. Variations in soil gradation were locally observed and included areas of increased gravel, silt, and sand contents; however, silty sand with gravel sand should be considered the predominant underlying soil type. Soils within the upper approximate three to five feet of existing grades were generally characterized as medium dense; thereafter, native soils become dense to very dense, extending to the terminus of each test pit location, which occurred between about 8 and 14 feet bgs. An exception occurred at TP-4, where the native soil was characterized as medium dense to the terminus of the test pit. Native soils were primarily observed in a moist condition at the time of the October 2022 fieldwork. The referenced WSS resource indicates the site is underlain by Alderwood gravelly sandy loam (Map Unit Symbol: AgC). This soil series is associated with ridges and hills and is derived from glacial drift. Based on the soil conditions encountered during the subsurface exploration, native soils are considered representative of ground moraine deposits, in accordance with local mapping designations. In our opinion, soil conditions within the off-site easement area will be of similar composition to the soils encountered on site. This opinion is based on review of the referenced WSS and geologic map resources, which depict similar soil conditions (Alderwood gravelly sandy loam and ground moraine deposits) across the easement area. Groundwater Groundwater was not encountered within the explored depths of the test pit locations during the October 2022 exploration. Groundwater seeps are common within glacial deposits, and the elevations and/or flow volumes of seepages can fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater elevations are higher during the winter, spring, and early summer months. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 4 Updated July 3, 2023 Earth Solutions NW, LLC Geologically Hazardous Areas Renton Municipal Code (RMC) 4-3-050 classifies geologically hazardous areas as those areas susceptible to damage relating to sensitive and protected slopes, landslides, erosion, seismic activity, and coal mines. Based on review of COR Maps, the site has been designated as a potential moderate coal mine hazard area. Steep slope areas are depicted on the adjacent property in the area of the proposed sewer easement. Furthermore, based on our review of the RMC, the site is considered to possess low erosion hazard potential. Erosion Hazard RMC 4-3-050G5ci defines a low erosion hazard (EL) as areas with soil characterized as having a slight or moderate erosion potential and a slope less than 15 percent. Based on review of the referenced King County Soil Survey, on-site Alderwood series (AgC) soils are considered to have a moderate erosion potential. As such, the site may be considered to possess a low erosion hazard. A review of the development standards table presented in section 4-3-050G2 indicates there are no required buffers or setbacks associated with EL areas. From a geotechnical standpoint, typical best management practices (BMPs) and permanent landscaping installations can successfully mitigate any potential soil erosion both during and after construction. Coal Mine Hazard COR Maps indicates the subject site is within a moderate coal mine hazard (CM) area. As defined in RMC 4-3-050G5eii, CM areas are defined as areas where mine workings are deeper than 200 feet for steeply dipping seams, or deeper than 15 times the thickness of the seam or workings for gently dipping seams. These areas may be affected by subsidence. Review of the referenced coal mine hazard maps suggests the site is within the vicinity of a historical coal mine operation. However, it appears that mining activity beneath the site area is greater than 200 feet. On this basis, the subject site is considered appropriately mapped within a CM area per the RMC definition. Per the development standards table presented in RMC 4-3- 050G2, there are no code-specified buffers or setbacks for CM areas “based on the results of a geotechnical report and/or independent review.” From a geotechnical standpoint, it is our opinion buffers and/or setbacks need not be applied to the project with respect to the CM area. Construction of the proposed residential development is not expected to increase the potential for ground subsidence on the subject site. This opinion relies on the validity of the information presented in the referenced coal mine maps. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 5 Updated July 3, 2023 Earth Solutions NW, LLC Steep Slopes According to RMC 4-3-050G5a, steep slopes are categorized into two types and are based on identification in the city’s Steep Slope Atlas or another method approved by the city: i. Sensitive Slopes: A hillside, or portion thereof (excluding engineering retaining walls), characterized by: a. An average slope of 25 percent to less than 40 percent. b. An average slope of 40 percent or greater, with a vertical rise of less than 15 feet. c. Abutting an average slope of 25 percent to 40 percent. ii. Protected Slopes: A hillside, or portion thereof, characterized by an average slope of 40 percent or greater grade and having a minimum vertical rise of 15 feet. The referenced COR Maps designates the site and the adjacent easement area as meeting the criteria of sensitive slopes, and the neighboring property is designated as meeting the criteria of both sensitive slopes and protected slopes. Based on review of the referenced utility plan (which depicts baseline survey data), the maximum slope gradients for the subject project are as follows:  Across the subject site, slope averages do not exceed 25 percent over a minimum vertical rise of 15 feet, and there are no slopes that exceed 40 percent over at least 10 feet of vertical rise.  Along the off-site sewer easement, there is at least one slope area with an average grade of approximately 30 percent over a vertical distance of 15 feet. Based on our review, neither sensitive slopes nor protected slopes are present across the subject property per RMC criteria. However, along the off-site sewer easement, at least one area meets the RMC definition of a sensitive slope (but not a protected slope). Per RMC 4-3-050G2, there is no applicable critical area buffer width or structure setback for sensitive slopes unless recommended in a geotechnical report, as a result of independent review, or pursuant to a requirement of the building code and/or official. Based on our understanding of the site geology and competent slope makeup, it is our opinion that buffer and setback distances need not be applied to the proposed off-site sewer easement. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, the construction of the proposed residential development is feasible from a geotechnical standpoint. The primary geotechnical considerations for the proposed development concern structural fill placement and compaction, foundation design, utility installation, and stormwater management design. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 6 Updated July 3, 2023 Earth Solutions NW, LLC Site Preparation and Earthwork Initial site preparation activities will consist of installing temporary erosion control measures, establishing grading limits, and site clearing and stripping activities. Subsequent earthwork activities will involve mass site grading and installation of infrastructure and stormwater management improvements. Temporary Erosion Control The following temporary erosion and sediment control Best Management Practices (TESC BMPs) are offered:  Temporary construction entrances and drive lanes should be constructed with at least six inches of quarry spalls to both minimize off-site soil tracking and provide a stable access entrance surface. A woven geotextile fabric can be placed beneath the quarry spalls to provide greater stability, if needed.  Silt fencing should be placed around the site perimeter.  When not in use, soil stockpiles should be covered or otherwise protected.  Temporary measures for controlling surface water runoff, such as interceptor trenches, sumps, or interceptor swales, should be installed before beginning earthwork activities.  Dry soils disturbed during construction should be wetted to reduce dust.  When appropriate, permanent planting or hydroseeding will help to stabilize site soils. Additional TESC BMPs, as specified by the project civil engineer on the plans, should be incorporated into construction activities. TESC measures will require upkeep and potential modification during construction to ensure proper function; such upkeep should be coordinated with the site erosion control lead, where applicable. Stripping Topsoil was generally encountered in the upper approximately 6 to 12 inches of existing grades at the test pit locations. For stripping estimations, an average topsoil thickness of about six inches can be assumed, based on our field observations. Where encountered, organic-rich topsoil should be stripped and segregated into a stockpile for later use on site or to be exported. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 7 Updated July 3, 2023 Earth Solutions NW, LLC Excavations and Slopes Based on the soil conditions observed at the test pit locations, the following allowable temporary slope inclinations, as a function of horizontal to vertical (H:V) inclination, may be used. The applicable Federal Occupation Safety and Health Administration (OSHA) and Washington Industrial Safety and Health Act (WISHA) soil classifications are also provided:  Loose to medium dense soil 1.5H:1V (Type C)  Areas exposing groundwater seepage 1.5H:1V (Type C)  Dense to very dense, undisturbed native soil 0.75H:1V (Type A) Steeper temporary slope inclinations within undisturbed, very dense native soil may be feasible based on the soil and groundwater conditions exposed within the excavations. ESNW can evaluate the feasibility of utilizing steeper temporary slopes on a case-by-case basis at the time of construction. In any case, an ESNW representative should observe temporary slopes to confirm inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope stability recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should be graded to 2H:1V (or flatter) and planted with vegetation to enhance stability and minimize erosion potential. Permanent slopes should be observed by ESNW before vegetation and landscaping. In-situ and Imported Soil Successful use of the on-site soil as structural fill will largely be dictated by the moisture content at the time of placement and compaction. Based on the conditions observed during the subsurface exploration, the native soils are considered to possess a moderate to high moisture sensitivity. Depending on the time of year construction occurs, remedial measures (such as soil aeration) may be necessary as part of site grading and earthwork activities. If the on-site soil cannot be successfully compacted, the use of imported soil may be necessary. In our opinion, a contingency should be provided in the project budget for the export of soil that cannot be successfully compacted as structural fill, particularly if grading activities take place during periods of extended rainfall activity. In general, soils with fines contents greater than 5 percent typically degrade rapidly when exposed to periods of rainfall. Imported structural fill soil should consist of well-graded, granular soil that can achieve a suitable working moisture content. During wet weather conditions, imported soil intended for use as structural fill should consist of a well-graded, granular soil with a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three-quarter-inch fraction). Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 8 Updated July 3, 2023 Earth Solutions NW, LLC Subgrade Preparation Foundation and slab subgrade surfaces should consist of competent, undisturbed native soil or structural fill placed and compacted atop competent native soil. ESNW should observe subgrade areas before placing formwork. Supplementary recommendations for subgrade improvement may be provided at the time of construction; such recommendations would likely include further mechanical compaction effort or overexcavation and replacement with suitable structural fill. Structural Fill Structural fill is defined as compacted soil placed in foundation, slab-on-grade, roadway, permanent slope, retaining wall, and utility trench backfill areas. The following recommendations are provided for soils intended for use as structural fill:  Moisture content At or slightly above optimum  Relative compaction (minimum) 95 percent (per ASTM D1557)  Loose lift thickness (maximum) 12 inches Existing site soil may only be considered suitable for use as structural fill if a suitable moisture content is achieved at the time of placement and compaction. If the on-site soil cannot achieve the above specifications, the use of imported structural fill material will likely be necessary. Concerning underground utility installations and backfill, local jurisdictions will likely dictate soil type(s) and compaction requirements. Foundations Based on our findings, the proposed single-family residences may be constructed on conventional continuous and spread footing foundations that bear directly on competent native soil, recompacted native soil, or new structural fill that is placed and compacted directly on competent native soil. Native soil conditions considered suitable for support of the proposed structures will likely be encountered beginning at a depth of about two feet bgs across most of the site. Areas of existing fill (such as at TP-4) will need to be removed or reworked to establish suitable bearing conditions in proposed structural areas, as recommended by ESNW at the time of construction. Where loose or unsuitable soil conditions are exposed at foundation subgrade elevations, compaction of the soil to the specifications of structural fill or overexcavation and replacement with suitable structural fill will be necessary. Provided the foundations will be supported as prescribed, the following parameters may be used for the design:  Allowable soil bearing capacity 2,500 psf  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 9 Updated July 3, 2023 Earth Solutions NW, LLC The above passive pressure and friction values include a factor-of-safety (FOS) of 1.5. A one- third increase in the allowable soil bearing capacity may be assumed for short-term wind and seismic loading conditions. With structural loading as expected, total settlement in the range of one inch and differential settlement of about one-half inch is anticipated. Most settlements should occur during construction when dead loads are applied. Seismic Design The 2018 International Building Code (2018 IBC) recognizes the most recent edition of the Minimum Design Loads for Buildings and Other Structures manual (ASCE 7-16) for seismic design, specifically concerning earthquake loads. Based on the soil conditions encountered at the test locations, the parameters and values provided below are recommended for seismic design per the 2018 IBC. Parameter Value Site Class C* Mapped short-period spectral response acceleration, SS (g) 1.407 Mapped 1-second period spectral response acceleration, S1 (g) 0.48 Short period site coefficient, Fa 1.2 Long-period site coefficient, Fv 1.5 Adjusted short-period spectral response acceleration, SMS (g) 1.689 Adjusted 1-second period spectral response acceleration, SM1 (g) 0.72 Design short-period spectral response acceleration, SDS (g) 1.126 Design 1-second period spectral response acceleration, SD1 (g) 0.48 * Assumes very dense soil conditions, encountered to a maximum depth of 14 feet bgs during the October 2022 field exploration, remain very dense to at least 100 feet bgs. Based on our experience with the project geologic setting (glacial till) across the Puget Sound region, soil conditions are likely consistent with this assumption. Further discussion between the project structural engineer, the project owner (or their representative), and ESNW may be prudent to determine the possible impacts on the structural design due to increased earthquake load requirements under the 2018 IBC. ESNW can provide additional consulting services to aid with design efforts, including supplementary geotechnical and geophysical investigation, upon request. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 10 Updated July 3, 2023 Earth Solutions NW, LLC Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during an earthquake. Soil profiles that are loose, cohesionless, and present below the groundwater table are most susceptible to liquefaction. During the ground shaking, the soil contracts, and porewater pressure increases. The increased porewater pressure occurs quickly and without sufficient time to dissipate, resulting in water flowing upward to the ground surface and a liquefied soil condition. Soil in a liquefied condition possesses very little shear strength in comparison to the drained condition, which can result in a loss of foundation support for structures. In our opinion, site susceptibility to liquefaction may be considered negligible. The absence of a shallow groundwater table and the dense characteristics of the native soil were the primary bases for this opinion. Slab-on-Grade Floors Slab-on-grade floors for the proposed residential structures should be supported by competent, firm, and unyielding subgrades. Unstable or yielding subgrade areas should be recompacted or overexcavated and replaced with suitable structural fill before slab construction. A capillary break consisting of at least four inches of free-draining crushed rock or gravel should be placed below each slab. The free-draining material should have a fines content of 5 percent or less (where the fines content is defined as the percent passing the Number 200 sieve, based on the minus three- quarter-inch fraction). In areas where slab moisture is undesirable, the installation of a vapor barrier below the slab should be considered. Vapor barriers should be made from material specifically designed for use as a vapor barrier and should be installed in accordance with the manufacturer’s recommendations. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for the design:  Active earth pressure (unrestrained condition) 35 pcf (equivalent fluid)  At-rest earth pressure (restrained condition) 55 pcf  Traffic surcharge* (passenger vehicles) 70 psf (rectangular distribution)  Passive earth pressure 300 pcf (equivalent fluid)  Coefficient of friction 0.40  Seismic surcharge 8H psf† * Where applicable. † Where H equals the retained height (in feet). Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 11 Updated July 3, 2023 Earth Solutions NW, LLC The above passive pressure and friction values include a FOS of 1.5 and are based on a level backfill condition and level grade at the wall toe. Revised design values will be necessary if sloping grades are to be used above or below retaining walls. Additional surcharge loading from adjacent foundations, sloped backfill, or other relevant loads should be included in the retaining wall design. Retaining walls should be backfilled with free-draining material that extends along with the height of the wall and a distance of at least 18 inches behind the wall. The upper 12 inches of the wall backfill may consist of less permeable soil, if desired. A sheet drain may be considered instead of using free-draining backfill. A perforated drainpipe should be placed along the base of the wall and connected to an approved discharge location. A typical retaining wall drainage detail is provided on Plate 3. If drainage is not provided, hydrostatic pressures should be included in the wall design. Drainage Zones of perched groundwater seepage could develop in site excavations depending on the time of year grading operations take place, particularly within deeper excavations for utilities and stormwater facilities. Temporary measures to control surface water runoff and groundwater during construction would likely involve interceptor trenches, interceptor swales, and sumps. ESNW should be consulted during preliminary grading to both identify areas of seepage and provide recommendations to reduce the potential for seepage-related instability. Finish grades must be designed to direct surface drain water away from structures and slopes. Water must not be allowed to pond adjacent to structures or slopes. In our opinion, foundation drains should be installed along building perimeter footings. A typical foundation drain detail is provided on Plate 4. Infiltration Feasibility From a geotechnical standpoint, full infiltration designs are considered infeasible for the project. The site is predominately underlain by glacially consolidated deposits that consist primarily of silty sand with gravel. As a result of the dense in-situ condition of the native soil and areas of appreciable fines contents, large-scale infiltration implementations would likely exhibit poor to negligible functionality and would not be expected to have suitable long-term performance. Small-scale BMP or LID designs (such as permeable pavement or shallow gravel-filled trenches) may be viable for the project; however, feasibility will largely depend on the grading plan, since any such implementation would need to target the weathered soil horizon located within the upper few feet of existing grades. As such, if significant grade cuts are proposed, small-scale BMP or LID designs will likely not be feasible from a geotechnical standpoint. If desired, ESNW can further evaluate the feasibility of incorporating small-scale BMP or LID designs into the project. If pursued, in-situ infiltration testing will likely be necessary to confirm the feasibility of utilizing such designs and to develop a suitable design infiltration rate. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 12 Updated July 3, 2023 Earth Solutions NW, LLC Preliminary Detention Vault Design We presume that stormwater management will likely be provided via a stormwater detention vault located within the southwestern site corner (Tract A). We anticipate grade cuts of 10 or more feet will be necessary to achieve the subgrade elevation of the vault foundation. Based on our field observations, grade cuts for the vault are likely to expose competent, native glacial till deposits. The vault foundation should be supported directly on very dense native soil or quarry spalls placed directly on competent native soil. The final vault design must incorporate adequate space from property boundaries such that temporary excavations to construct the vault structure may be successfully completed using the recommended temporary slope inclinations provided in this report. Perimeter drains should be installed around the vault and conveyed to an approved discharge point. In our opinion, perched groundwater seepage should be anticipated along the temporary excavation made for construction of the vault; however, buoyancy is not expected to impact the vault design. The following preliminary design parameters may be used for the vault:  Allowable soil bearing capacity 5,000 psf  Active earth pressure (unrestrained) 35 pcf  Active earth pressure (unrestrained, hydrostatic) 80 pcf  At-rest earth pressure (restrained) 55 pcf  At-rest earth pressure (restrained, hydrostatic) 100 pcf  Coefficient of friction 0.40  Passive earth pressure 350 pcf  Seismic surcharge 8H psf* * Where H equals the retained height (in feet). The passive earth pressure and coefficient of friction values include a FOS of 1.5. Vault retaining walls should be backfilled with free-draining material or suitable sheet drainage that extends along the height of the walls. The upper one foot of the wall backfill may consist of a less permeable soil, if desired. A perforated-rigid drainpipe should be placed along the base of the wall and connected to an approved discharge location. If the elevation of the vault bottom is such that gravity flow to an outlet is not possible, the portions of the vault below the drain should be designed to include hydrostatic pressure. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 13 Updated July 3, 2023 Earth Solutions NW, LLC It is our recommendation that ESNW, the owner, and the contractor observe the excavation of a test pit within the vault area prior to excavation activities. The test pit exploration will assist in confirming anticipated soil conditions at the vault subgrade and characterizing seasonal groundwater conditions, which may impact the temporary excavation and grading plan. Preliminary Pavement Sections The performance of site pavements is largely related to the condition of the underlying subgrade. To ensure adequate pavement performance, the subgrade should be in a firm and unyielding condition when subjected to proofrolling with a loaded dump truck. Structural fill in pavement areas should be compacted to the specifications previously detailed in this report. Soft, wet, or otherwise unsuitable subgrade areas may still exist after base grading activities. Areas containing unsuitable or yielding subgrade conditions will require remedial measures, such as overexcavation and/or placement of thicker crushed rock or structural fill sections, before pavement. We anticipate new pavement sections will be subjected primarily to passenger vehicle traffic. For lightly loaded pavement areas subjected primarily to passenger vehicles, the following preliminary pavement sections may be considered:  A minimum of two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB).  A minimum of two inches of HMA placed over three inches of asphalt-treated base (ATB). Heavier traffic areas generally require thicker pavement sections depending on site usage, pavement life expectancy, and site traffic. For preliminary design purposes, the following pavement sections for occasional truck traffic and access roadways areas may be considered:  Three inches of HMA placed over six inches of CRB.  Three inches of HMA placed over four-and-one-half inches of ATB. An ESNW representative should be requested to observe subgrade conditions before the placement of CRB or ATB. As necessary, supplemental recommendations for achieving subgrade stability and drainage can be provided. If the on-site roads will be constructed with an inverted crown, additional drainage measures may be recommended to assist in maintaining road subgrade and pavement stability. Final pavement design recommendations, including recommendations for heavy traffic areas, access roads, and frontage improvement areas, can be provided once final traffic loading has been determined. Road standards utilized by the governing jurisdiction may supersede the recommendations provided in this report. The HMA, ATB, and CRB materials should conform to WSDOT specifications, where applicable. All soil base material should be compacted to a relative compaction of 95 percent, based on the laboratory maximum dry density as determined by ASTM D1557. Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 14 Updated July 3, 2023 Earth Solutions NW, LLC Utility Support and Trench Backfill In our opinion, the native soil will generally be suitable for the support of utilities. Remedial measures may be necessary for some areas to provide support for utilities, such as overexcavation and replacement with structural fill and/or placement of geotextile fabric. Groundwater seepage may be encountered within utility excavations, and caving of trench walls may occur where groundwater is encountered. Depending on the time of year and conditions encountered, dewatering or temporary trench shoring may be necessary during utility excavation and installation. The native soil is not considered suitable for use as structural backfill throughout the utility trench excavations unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. Moisture conditioning of the soil may be necessary at some locations before use as structural fill. Each section of the utility lines must be adequately supported by the bedding material. Utility trench backfill should be placed and compacted to the structural fill specifications previously detailed in this report or to the applicable specifications of the presiding jurisdiction. LIMITATIONS This study has been prepared for the exclusive use of Ichijo USA Co., Ltd. and its representatives. The recommendations and conclusions provided in this study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. No warranty, express or implied, is made. Variations in the soil and groundwater conditions observed at the test locations may exist and may not become evident until construction. ESNW should reevaluate the conclusions provided in this study if variations are encountered. Additional Services ESNW should have an opportunity to review the final project plans concerning the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services during construction. Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutionsNWLLC Vicinity Map Harmony Ridge Renton,Washington Reference: King County,Washington OpenStreetMap.org NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Renton Plate Proj.No. Date Checked Drawn Earth Solutions NWLLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services Earth Solutions NWLLC Earth Solutions NWLLC MRS NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-8888,Oct.2022 Subject Site Proposed Lot Number 0 100 200 Scale in Feet1"=200' SES 06/30/2023 8888.01 2 Test Pit Location Plan Harmony Ridge Renton, Washington TP-1 10 TP-1 TP-2 TP-3 TP-4 TP-5TP-6 TP-7 TP-8 TP-10 TP-11 TP-12 TP-9 1 2 3 4 5 67 8 9 10 11 1213 14 15 16 17 18 19 20 116TH AVENUE S.E. S.E. 157THSTREET 118 T H A V E N U E S.E. 21 22 TractA Tract B Tract C Tract D Sewer Easement S.E. 19 T H S T R E E T Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutionsNWLLC NOTES: Free-draining Backfill should consist of soil having less than 5 percent fines. Percent passing No.4 sieve should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free-draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1-inch Drain Rock. LEGEND: Free-draining Structural Backfill 1-inch Drain Rock 18"Min. Structural Fill Perforated Rigid Drain Pipe (Surround in Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Retaining Wall Drainage Detail Harmony Ridge Renton,Washington Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked SES Date June 2023 Date 06/30/2023 Proj.No.8888.01 Plate 4 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutionsNWLLC Slope Perforated Rigid Drain Pipe (Surround in Drain Rock) 18"Min. NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal:native soil or other low-permeability material. 1-inch Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Footing Drain Detail Harmony Ridge Renton,Washington Earth Solutions NW, LLC Appendix A Subsurface Exploration Test Pit Logs ES-8888 Subsurface conditions at the subject site were explored on October 17, 2022. Twelve test pits were excavated using a trackhoe and operator retained by ESNW. The approximate locations of the test pits are illustrated on Plate 2 of this study. The test pit logs are provided in this Appendix. The test pits were advanced to a maximum depth of approximately 14 feet bgs. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. > 12% Fines < 5% Fines Highly Organic Soils Silts and Clays Liquid Limit 50 or More Silts and Clays Liquid Limit Less Than 50 Fine-Grained Soils - 50% or More Passes No. 200 Sieve Coarse-Grained Soils - More Than 50% Retained on No. 200 Sieve Sands - 50% or More of Coarse Fraction Passes No. 4 Sieve Gravels - More Than 50% of Coarse Fraction Retained on No. 4 Sieve > 12% Fines < 5% Fines GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT Well-graded gravel with or without sand,little to no fines Poorly graded gravel with or without sand,little to no fines Silty gravel with or without sand Clayey gravel with or without sand Well-graded sand with or without gravel,little to no fines Poorly graded sand with or without gravel,little to no fines Silty sand with or without gravel Clayey sand with or without gravel Silt with or without sand or gravel;sandy or gravelly silt Clay of low to medium plasticity;lean clay with or without sand or gravel; sandy or gravelly lean clay Organic clay or silt of low plasticity Elastic silt with or withoutsandorgravel;sandy or gravelly elastic silt Clay of high plasticity; fat clay with or without sand or gravel;sandy or gravelly fat clay Organic clay or silt of medium to high plasticity Peat,muck,and other highly organic soils EEaarrtthh SSoolluuttiioonnss NNWWLLC Geotechnical Engineering,ConstructionObservation/Testing and Environmental Services EXPLORATION LOG KEY Fill FILL Made Ground Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visualfieldand/or laboratory observations,which include density/consistency,moisture condition,grain size,andplasticityestimates,and should not be construed to imply field or laboratory testing unless presented herein. Visual-manual and/or laboratory classification methods of ASTM D2487 and D2488 were used as an identification guide for the Unified Soil Classification System. Terms Describing Relative Density and Consistency Coarse-Grained Soils: Fine-Grained Soils: SPT blows/foot SPT blows/foot Test Symbols &Units Fines =Fines Content (%) MC =Moisture Content (%) DD =Dry Density (pcf) Str =Shear Strength (tsf) PID =Photoionization Detector (ppm) OC =Organic Content (%) CEC =Cation Exchange Capacity (meq/100 g) LL =Liquid Limit (%) PL =Plastic Limit (%) PI =Plasticity Index (%) Component Definitions Descriptive Term Size Range and Sieve Number Smaller than No.200 (0.075 mm) Boulders Modifier Definitions Percentage by Weight (Approx.) <5 5 to 14 15 to 29 >30_ Modifier Trace (sand,silt,clay,gravel) Slightly (sandy,silty,clayey,gravelly) Sandy,silty,clayey,gravelly Very (sandy,silty,clayey,gravelly) Moisture Content Dry -Absence of moisture,dusty,dry to the touch Damp -Perceptible moisture,likely below optimum MC Moist -Damp but no visible water,likely at/near optimum MC Wet -Water visible but not free draining, likely above optimum MC Saturated/Water Bearing -Visible free water,typically below groundwater table Symbols Cement groutsurfaceseal Bentonite chips Grout 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) _>50 Density Very Loose Loose Medium Dense Dense Very Dense Consistency Very Soft Soft Medium Stiff Stiff Very Stiff Hard <4 4 to 9 10 to 29 30 to 49 <2 2 to 3 4 to 7 8 to 14 15 to 29 _>30 EEaarrtthh NNWWLLC EarthSolutionsNWLLC Cobbles GravelCoarse GravelFineGravel Sand Coarse Sand Medium Sand Fine Sand Silt and Clay Larger than 12" 3"to 12" 3"to No.4 (4.75 mm)3"to 3/4"3/4"to No.4 (4.75 mm) No.4 (4.75 mm)to No.200 (0.075 mm) 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) MC = 5.3 MC = 3.0 MC = 5.5 Fines = 8.7 MC = 10.9 MC = 8.8Fines = 7.6 OC = 0.8CEC = 4.8 TPSL SM SP- SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense to dense, damp -becomes dense-probed 2" -becomes weakly cemented Brown poorly graded SAND with silt, loose to medium dense, damp [USDA Classification: slightly gravelly SAND] -becomes medium dense, moist -increasing gravels [USDA Classification: gravelly SAND] Test pit terminated 13.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 6.5 13.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46358 LONGITUDE -122.188 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-1 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 6.8 MC = 4.7 MC = 6.2 TPSL SM SP-SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 2" -becomes gray, dense-probed 1" -weakly cemented Gray poorly graded SAND with silt and gravel, medium dense, damp Test pit terminated at 11.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as astandalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 7.5 11.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46387 LONGITUDE -122.18776 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-2 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 4.4Fines = 36.0 MC = 9.9 MC = 6.1 MC = 4.1 TPSL SM SP-SM Dark brown TOPSOIL, root intrusions to 1.5' Brown silty SAND with gravel, medium dense, damp [USDA Classification: gravelly sandy LOAM] -probed 1" -becomes dense -probed <1" -weakly cemented Brown poorly graded SAND with silt, medium dense, damp Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 9.0 10.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46418 LONGITUDE -122.1872 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-3 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 6.0 MC = 5.8 MC = 4.8 MC = 3.8 TPSL SM SM Dark brown TOPSOIL, shallow root intrusions (Fill) Brown silty SAND with gravel, dense, damp (Fill) -becomes gray, dense pieces -probed <1" -topsoil horizon at 5' Brown silty SAND with gravel, medium dense, damp -weathered soils Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 5.0 10.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46371 LONGITUDE -122.18641 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-4 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 4.4 MC = 9.9 MC = 6.8Fines = 53.5 MC = 6.4 TPSL SM ML Dark brown TOPSOIL, root intrusions to 3' Brown silty SAND with gravel, medium dense to dense, damp -probed 2" Brown sandy SILT, dense, damp-probed <1" -becomes gray, dense to very dense [USDA Classification: slightly gravelly LOAM] Test pit terminated at 10.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 3.5 10.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46325 LONGITUDE -122.18844 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-5 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 6.5 MC = 8.9 MC = 3.2 TPSL SM SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 1" -becomes gray, weakly cemented -becomes dense Brown silty SAND, dense, moist Test pit terminated at 14.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 1.0 13.0 14.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46336 LONGITUDE -122.18776 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-6 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 3.7 MC = 4.7OC = 0.7 CEC = 3.0 MC = 6.1 MC = 4.5Fines = 13.8 TPSL GM SM Dark brown TOPSOIL, root intrusions to 3' Brown silty GRAVEL with sand, medium dense, damp -probed <1" -becomes dense -weakly cemented Brown silty SAND, dense, damp [USDA Classification: gravelly loamy SAND] Test pit terminated at 12.0 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as astandalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 6.5 12.0 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46364 LONGITUDE -122.18817 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-7 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 2.9 MC = 4.5 MC = 4.1 Fines = 15.2 MC = 7.2OC = 0.7 CEC = 3.4 TPSL GM SM Dark brown TOPSOIL, root intrusions to 2' Brown silty GRAVEL with sand, medium dense, damp -probed 1.5" -becomes gray, dense-probed <1" Brown silty SAND with gravel, medium dense, damp [USDA Classification: very gravelly loamy SAND] Test pit terminated at 10.5 feet below existing grade. No groundwater encountered during excavation. No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as astandalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 1.0 7.5 10.5 DE P T H (f t ) 0 5 10 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46361 LONGITUDE -122.18772 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-8 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 7.2 MC = 3.0 TPSL SM Dark brown TOPSOIL, minimal root intrusions Brown silty SAND with gravel, medium dense, damp -becomes gray, dense -weakly cemented Test pit terminated at 8.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed. Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 8.0 DE P T H (f t ) 0 5 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46352 LONGITUDE -122.18669 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-9 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 8.6 MC = 9.4 TPSL SM Dark brown TOPSOIL, minimal root intrusions Brown silty SAND with gravel, medium dense, damp -probed 1" -becomes gray, dense -weakly cemented Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 9.0 DE P T H (f t ) 0 5 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46357 LONGITUDE -122.1873 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-10 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 5.0 MC = 12.2 MC = 3.2 TPSL GM SM Dark brown TOPSOIL, minimal root intrusions Brown silty GRAVEL with sand, medium dense, damp -probed <1" Gray silty SAND with gravel, dense, moist -becomes damp Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 4.0 9.0 DE P T H (f t ) 0 5 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46386 LONGITUDE -122.18699 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-11 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G MC = 6.8 MC = 5.4 MC = 7.0 TPSL SM Dark brown TOPSOIL, root intrusions to 2' Brown silty SAND with gravel, medium dense, damp -probed 1.5" -becomes gray, dense-probed <1" -weakly cemented Test pit terminated at 9.0 feet below existing grade. No groundwater encountered during excavation.No caving observed. LIMITATIONS: Ground elevation (if listed) is approximate; the test location was not surveyed.Coordinates are approximate and based on the WGS84 datum. Do not rely on this test log as a standalone document. Refer to the text of the geotechnical report for a complete understanding ofsubsurface conditions. 0.5 9.0 DE P T H (f t ) 0 5 SA M P L E T Y P E NU M B E R EXCAVATION CONTRACTOR NW Excavating DATE STARTED 10/17/22 COMPLETED 10/17/22 GROUND WATER LEVEL: GROUND ELEVATION LATITUDE 47.46394 LONGITUDE -122.18649 LOGGED BY SES CHECKED BY KDH NOTES SURFACE CONDITIONS Duff AT TIME OF EXCAVATIONAT TIME OF EXCAVATION AFTER EXCAVATION PAGE 1 OF 1 TEST PIT NUMBER TP-12 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GE N E R A L B H / T P / W E L L - 8 8 8 8 . G P J - G I N T U S . G D T - 7 / 3 / 2 3 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 4254494711 TESTS U. S . C . S . MATERIAL DESCRIPTION GR A P H I C LO G Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-8888 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 8.7 7.6 36.0 53.5 13.8 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Slightly Gravelly Sand. USCS: SP-SM. USDA: Brown Gravelly Sand. USCS: SP-SM with Gravel. USDA: Brown Gravelly Sandy Loam. USCS: SM with Gravel. USDA: Gray Slightly Gravelly Loam. USCS: Sandy ML. USDA: Brown Gravelly Loamy Sand. USCS: SM. 6 60 PE R C E N T F I N E R B Y W E I G H T D10 0.232 0.315 0.259 0.362 0.544 0.399 0.156 0.486 GRAIN SIZE DISTRIBUTION 100 4.02 3.45 LL TP-01 TP-01 TP-03 TP-05 TP-07 0.09 0.158 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 4.75 19 37.5 19 19 %Silt 1.65 1.16 TP-01 TP-01 TP-03 TP-05 TP-07 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 7.5ft. 13.0ft. 2.0ft. 5.5ft. 12.0ft. 7.50ft. 13.00ft. 2.00ft. 5.50ft. 12.00ft. PL PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GR A I N S I Z E U S D A E S - 8 8 8 8 U N I T E D C H R I S T I A N C H U R C H P R O P E R T Y . G P J G I N T U S L A B . G D T 1 0 / 2 1 / 2 2 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 15.2 21.8 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Brown Very Gravelly Loamy Sand. USCS: SM with Gravel. USDA: Brown Very Gravelly Sandy Loam. USCS: GM with Sand. 6 60 PE R C E N T F I N E R B Y W E I G H T D10 0.33 0.266 4.135 9.182 GRAIN SIZE DISTRIBUTION 100 LL TP-08 TP-11 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 37.5 37.5 %Silt TP-08 TP-11 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 8.0ft. 3.0ft. 8.00ft. 3.00ft. PL PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GR A I N S I Z E U S D A E S - 8 8 8 8 U N I T E D C H R I S T I A N C H U R C H P R O P E R T Y . G P J G I N T U S L A B . G D T 1 0 / 2 1 / 2 2 Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 Earth Solutions NW, LLC Report Distribution ES-8888 EMAIL ONLY Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Kanon Kupferer EMAIL ONLY Barghausen Consulting Engineers, Inc. 18215 – 72nd Avenue South Kent, Washington 98032 Attention: Barry Talkington, P.E. Ivana Halvorsen Vicente Varas, P.E. Final Tree Protection Plan prepared by Washington Forestry Consultants, Inc. dated August 21, 2025 6.2 WASHINGTON FORESTRY CONSULTANTS, INC. FORESTRY AND VEGETATION MANAGEMENT SPECIALISTS W F C I O: 360/943-1723 C: 360/561-4407 9136 Yelm Hwy SE Olympia, WA 98513 URBAN/RURAL FORESTRY • TREE APPRAISAL • TREE RISK ASSESSMENT RIGHT-OF-WAYS • VEGETATION MANAGEMENT • FOREST/TREE MGT. PLANS • EXPERT TESTIMONY Member of International Society of Arboriculture and Society of American Foresters -Final Tree Protection Plan- HARMONY RIDGE PLAT 15509 116th Avenue SE Renton, WA 98058 Prepared for: Barghausen Consulting Engineers, Inc. Prepared by: Washington Forestry Consultants, Inc. Date of Report: August 21, 2025 Introduction The project proponent is planning to construct a new 21-lot plat on 6.27 acres at 15509 116th Avenue SE in Renton. The proponent has retained WFCI to: •Evaluate and inventory all trees on the site pursuant to the requirements of the City of Renton Tree Protection Ordinance. •Make recommendations for retention of significant trees, along with required protectionand cultural measures. Observations Methodology WFCI has evaluated all trees 6 inches diameter at breast height (DBH) and larger in the forested area of the site using standard forestry sampling methodology. Seven variable area plots were installed on a systematic grid across the forested portion of the site. The plot locations are marked in the field with pink and black stripped flagging. Data from the counts of significant trees were entered into SuperAce®, a forest inventory software program that projected the total number of significant trees on the site. This plot data will be used to determine the tree retention requirement. Sampling was designed to achieve a 95% confidence level for the projection of the population of significant trees. A 100% inventory was conducted in the non-forested area of the site. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 2 To be a significant tree, it must have a condition rating of Fair or better. Trees rated as Poor, Very Poor, or Dead or are defective, diseased and/or in decline and are not long-term trees and are not considered to be significant trees. The tree evaluation phase used methodology developed by Nelda Matheny and Dr. James Clark in their 1998 publication Trees and Development: A Technical Guide to Preservation of Trees during Land Development. Site Description The main area of the project is a 6.27-acre parcel with three church buildings, a playground and parking lot currently occupying the northern portion of the parcel. The site is mostly forested with the buildings in the northern part of the parcel. The topography is mostly flat to gently rolling with a westerly aspect. The project is bordered by a forested lot to the north, 116th Avenue SE to the east, and single-family homes to the south and west. A utility extension area that will also be cleared extends from the site to the northwest. Soils Description According to the USDA Natural Resource Conservation Service soil survey there are two soil types in the project area. The first type is the Alderwood gravelly sandy loam, a moderately deep, moderately well drained soil found on glacial till plains. It is formed in ablation till overlying basal till. A weakly cemented hardpan is at a depth of 20 to 40 inches. Permeability is moderately rapid above the hardpan and very slow in the pan. Available water capacity is low. The effective rooting depth for trees is 20- 40 inches. A perched seasonal high-water table is at a depth of 18-36 inches from November to March. The potential for windthrow of trees is moderate under normal conditions. New trees require irrigation for establishment. In areas where grading brings the Alderwood hardpan nearer to the surface, the hardpan must be fractured under new trees to provide soil volume for root development and to improve drainage around the tree. The second is the Arents-Alderwood material, a moderately deep, moderately well drained soil found on glacial till plains. It is formed in ablation till overlying basal till. A weakly cemented hardpan is at a depth of 20 to 40 inches. Permeability is moderately rapid above the hardpan and very slow in the pan. Available water capacity is very low. The effective rooting depth for trees is 20-40 inches. The potential for windthrow of trees is moderate under normal conditions. New trees require irrigation for establishment. In areas where grading brings the hardpan nearer to the surface, the hardpan must be fractured under new trees to provide soil volume for root development and to improve drainage around the tree. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 3 Figure 1. Harmony Ridge Plat Soils Map AgC – Alderwood gravelly sandy loam AmC – Arents-Alderwood material Existing Tree Conditions There are two forest cover type for the purpose of description. The aerial photo of the parcel is shown in Appendix I. Type I. -- This cover type is the developed portion of the parcel. There are a total of 13 trees in the type. The size of significant trees ranges from 8 inches to 24 inches in diameter at breast height (DBH). Tree species include bigleaf maple (Acer macrophyllum), Callery pear (Pyrus calleryana), Colorado blue spruce (Picea pungens), flowering dogwood (Corus florida), honey locust (Gleditsia triacanthos), Raywood ash (Fraxinus oxycarpa ‘Raywood’), western hemlock (Tsuga heterophylla), and western redcedar (Thuja plicata). Tree conditions on the site range from ‘Dead’ to ‘Good,’ with most trees (92%) described as being in ‘Fair’ or better condition. Most of the trees were planted in the landscape and will make quality save trees. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 4 Table 1. Summary of trees in Type I of Harmony Ridge Plat. Species DBH Range (in.) Condition Range Total # of Trees # of Healthy Trees # of Unhealthy Trees* Species Composition of the Stand Bigleaf Maple 8 – 24 Fair – Good 5 5 0 38% Callery Pear 11 Fair 1 1 0 8% Colorado Blue Spruce 12 Fair 1 1 0 8% Flowering Dogwood 20 Fair 1 1 0 8% Honey Locust 8 – 10 Fair 2 2 0 15% Raywood Ash 14 Fair 1 1 0 8% Western Hemlock 10 Dead 1 0 1 8% Western Redcedar 20 Fair 1 1 0 8% Sum 8 – 24 Dead – Good 13 12 1 100% *Trees rated as dead, very poor, or poor. In summary, 12 of the 13 significant trees could be potentially retained on this site when only tree health is considered. The understory vegetation throughout the type is plants in the landscaping, grass, and weeds. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 5 Photo 1: View of Cover Type I of the project area. Type II. -- This cover type is the forested portion of the site. There are a total of 391 trees in the type. The size of significant trees ranges from 6 inches to 36 inches in diameter at breast height (DBH). Tree species include bigleaf maple, Douglas-fir (Pseudotsuga menziesii), bird cherry (Prunus avium), red alder (Alnus rubra), and black cottonwood (Populus trichocarpa). Tree conditions on the site range from ‘Dead’ to ‘Good,’ with most trees (93%) described as being in ‘Fair’ or better condition. The trees were naturally seeded or are stump sprouts from the last harvest. The larger trees in the site will not make quality save trees and only smaller diameter trees have potential to be retained. Table 2. Summary of trees in Type II of Harmony Ridge Plat. Species DBH Range (in.) Condition Range Total # of Trees # of Healthy Trees # of Unhealthy Trees* Species Composition of the Stand Bigleaf Maple 6 – 45 Dead – Good 296 284 12 76% Black Cottonwood 6 – 44 Poor – Fair 44 34 10 11% Bird Cherry 6 – 16 Very Poor – Fair 15 12 3 4% Douglas-fir 7 – 36 Fair – Good 22 22 0 6% Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 6 Species DBH Range (in.) Condition Range Total # of Trees # of Healthy Trees # of Unhealthy Trees* Species Composition of the Stand Red Alder 6 – 18 Dead – Fair 14 11 3 3% Sum 6 – 45 Dead – Good 391 363 28 100% *Trees rated as dead, very poor, or poor. The understory vegetation in the type is Indian plum (Oemleria cerasiformis), sword fern (Polystichum munitum), Oregon grape (Mahonia nervosa), holly (Ilex aquifolium), English ivy (Hedera helix), Himalayan blackberry (Rubus armeniacus), and yellow archangel (Lamium galeobdolon). Photo 2: View of Cover Type II of the project area. Off-site Impacts No offsite trees will be impacted by this project. Tree retention areas are located around the perimeter of the site near all offsite trees. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 7 Discussion Main Project Area Planned Tree Retention Ten trees around the existing church building will be retained. Forty-eight trees will be retained in Tract B and 15 trees in Tract D will be saved. Five trees on Lots 12 & 13 will also be saved. Total number of trees planned to be saved on the site is 78 trees. Tree Density Calculations Title 4-4-130H of the Renton Municipal Code (RMC) requires 30% of the significant trees on the site to be retained. There are a total of 404 significant sized trees on the parcel. After allowed tree deductions 308 trees remain for calculating the 30% requirement. A total of 92 significant trees will need to be retained in the project area to meet the requirement. Total # of Significant Trees: 404 Trees # of High Risk Significant Trees: 29 Trees # of Trees in the Public Rights-of-Ways: 67 Trees # of Significant Trees After Deductions: 308 Trees # of Significant Trees Required to be Saved: 92 Trees # of Significant Trees Planned to be Saved 78 Trees Shortfall of Significant Tree Requirement 14 Trees Additionally, RMC requires a minimum tree credit density of 30 tree credits per acre of net developable acreage. The following is a summary of the projected tree density requirements: Gross Site Acreage: 6.27 Acres Designated Public Rights-of-way: 1.21 Acres Net Developable Acres: 5.06 Acres Required Tree Credit Density (5.06 Acres x 30 Credits/Acre): 152.0 Tree Credits Proposed Tree Retention: Developed Areas (78 trees) 464.0 Tree Credits Excess of Tree Credit Requirement: 312.0 Tree Credits By retaining 78 of the significant trees on the site, this plan falls short of the minimum significant tree retention requirement by 14 trees. Required tree credit retention exceeds the minimum tree credits by 312.0 credits. Twenty-five additional trees will be required to be replanted to replace the 30% minimum shortfall. When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper deciduous or an evergreen at least six feet Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 8 (6') tall, shall be planted based on the tree credit value of each protected tree removed. A fee in lieu of tree planting, the cost of which can be determined by the City of Renton can also substitute for tree replacement if replanting on-site is not feasible. The topography of the site requires significant grading to complete the project. This site work limits the number of trees that can be retained in the interior area of the project. All trees being retained are located in Tier 1 tree tracts, as described by RMC tree preservation priority within subdivisions. The retained significant trees form a continuous canopy in the designated tracts. Off-site Utility Extension Area Trees Removed for Project Sixty-one trees will need to be removed to complete the extension area construction. Fifty of the trees are healthy, long-term trees and eleven trees are unhealthy. Eight trees will be retained. Tree Density Calculations Title 4-4-130H of the Renton Municipal Code (RMC) requires 30% of the significant trees to be retained. There are a total of 61 significant sized trees that require removal for the project. After allowed tree deductions 50 trees remain for calculating the 30% requirement. A total of 15 significant trees will need to be retained in the project area to meet the requirement. Total # of Significant Trees: 61 Trees # of High Risk Significant Trees: 11 Trees # of Significant Trees After Deductions: 50 Trees # of Significant Trees Required to be Saved: (50 x 30%) 15 Trees # of Significant Trees Planned to be Saved 8 Trees Shortfall of Significant Tree Requirement 7 Trees Additionally, RMC requires a minimum tree credit density of 30 tree credits per acre of net developable acreage. The following is a summary of the projected tree density requirements: Gross Site Acreage: 0.49 Acres Required Tree Credit Density (0.49 Acres x 30 Credits/Acre): 15.0 Tree Credits Proposed Tree Retention: (8 trees) 44.0 Tree Credits Excess of Tree Credit Requirement: 29.0 Tree Credits By retaining 8 of the significant trees in the utility area, this plan falls short of the minimum significant tree retention requirement by 7 trees. Required tree credit retention exceeds the minimum tree credits by 29.0 credits. Trees will be required to be replanted to replace the shortfalls. Tree replacement is necessary because of the unique type of project being proposed, no Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 9 alternative plans are available to retain more trees. The trees being removed equates to 134 replacement credits. Recommendations Tree Protection Measures Off-site edge trees must be protected during construction by a temporary chain-link fence (Attachment 7), located at the property line. Placards shall be placed on the fencing every 50 feet indicating the words, "NO TRESPASSING - Protected Trees". The individual tree protection zone (TPZ) is the dripline (6 feet minimum), unless otherwise delineated by WFCI in the field and described in the attached tree list (Table 2). If approved, the silt-fence could double as the tree protection fence for select off-site trees. Tree protection fences should be placed around the edge of the TPZ. The fence should be erected after logging but prior to the start of clearing. The fences should be maintained until the start of the landscape installation. There should be no equipment activity (including rototilling) within the root protection zone. No irrigation lines, trenches, or other utilities should be installed within the TPZ. Cuts or fills should impact no more than 20% of a tree’s root system. If topsoil is added to the root zone of a protected tree, the depth should not exceed 2 inches of a sandy loam or loamy fine sand topsoil and should not cover more than 20% of the root system. If roots are encountered outside the TPZ during construction, they should be cut cleanly with a saw and covered immediately with moist soil. Noxious vegetation within the root protection zone should be removed by hand. If a proposed save tree must be impacted by grading or fills more than allowed for by WFCI in the tree list, then the tree should be re-evaluated by WFCI to determine if the tree can be saved with mitigating measures, or if the tree should be removed. Tree Protection From Pedestrian Path A permeable pavement path is proposed to be installed within the tree protection zone of two save trees in the tree tract on the southern property line. The pathway will encroach upon 25% of the TPZ of tree #552342 and 9% of tree #552334. The encroachment of #552342 is above the recommended 20% coverage but based on the age and health of the tree the intrusion will be acceptable causing little to no impact to tree health. The path will be placed on a small amount of fill to level out the area. The permeable pavement will allow water and air to move down to the root system of the trees. The tree protection fencing should be placed at the edge of the save tree area during clearing and grading of the site. Prior to construction of the pathway the fencing can be moved to the edge of the path to allow the required leveling and pavement installation within the tree protection zones. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 10 Figure 1. Site plan of proposed permeable pavement path. Pruning and Thinning Pruning should be done to coincide with land clearing, to facilitate clean-up and while access to the trees is available (before houses are constructed). All individual trees to be saved near or within developed areas should have their crowns raised to provide a minimum of 8 feet of ground clearance over sidewalks and landscape areas, 15 feet over parking lots or streets, and at least 10 feet of building clearance. Care will need to be taken to avoid trespass when pruning offsite trees. This is best achieved by getting cooperation and permission from the tree owner. If no permission is obtained, then legally one cannot prune beyond the property line – ground to sky. All pruning should be done according to the ANSI A300 standards for proper pruning, and be completed by an International Society of Arboriculture Certified Arborist®, or be supervised by a Certified Arborist®. Conclusions and Timeline for Activity 1. Seventy-eight significant trees equaling 464.0 tree credits are proposed to be retained on the main project area of the site. 2. Sixty-one trees will be removed in the off-site utility extension area. 3. The final, approved tree protection plan map should be included in the construction drawings for bid and construction of the project and should be labeled as such. 4. Stake and heavily flag the clearing limits. 5. Contact WFCI to attend pre-job conference and discuss tree protection issues with contractors. WFCI can verify all trees to be saved and/or removed are adequately marked. 6. Conduct logging. Complete necessary hazard tree removals and invasive plant removals from the tree protection areas. No equipment should enter the tree protection areas during logging. Tree Protection Area Encroachments Fence Location During Clearing – Red Line Fence Location During Path Installation – Blue Line Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 11 7. Before land clearing is complete, do all necessary pruning on save trees and off-site trees to provided new home clearances. 8. Contact WFCI to inspect the tree tracts after logging, but prior to land clearing to identify any additional hazard trees that should be removed. 9. Install tree protection fences along the 'limits of construction'. The fences should be located at the limits of construction or at the dripline of the save tree or as otherwise specified by WFCI. Maintain fences throughout construction. 10. Complete clearing of the project. 11. Do not excavate stumps within 10’ of trees to be saved. These should be individually evaluated by WFCI to determine the method of removal. 12. Complete grading and construction of the project. 13. Contact WFCI to final inspect the tree protection areas after grading. 14. All save trees within reach of targets should be inspected annually for 2 years by a qualified professional forester retained by the homeowner’s association, and bi-annually thereafter. The purpose of these inspections is to identify trees that develop problems due to changing micro-site conditions and to prescribe cultural care or removal. Summary The City of Renton Municipal Code calls for 92 of the healthy, significant trees and 152.0 tree credits be retained on the main area of the site. Based on the current site plan, 78 existing trees equaling 464.0 tree credits will be retained. An additional 25 trees will be required to replace the 30% significant tree requirement shortfall. Eight significant trees will be saved in the off-site utility extension area on the site, falling short of the minimum significant tree retention requirement by 7 trees. Required tree credit retention exceeds the minimum tree credits by 29.0 credits. The trees being removed equates to 134 replacement credits. Please give us a call if you have any questions. Respectfully submitted, Washington Forestry Consultants, Inc. Galen M. Wright, ACF, ASCA Joshua Sharpes ISA Bd. Certified Master Arborist PN-129BU Professional Forester Certified Forester No. 44 ISA Certified Arborist®, ISA Tree Risk Assessor Qualified Urban Forest Professional, PN- 5939AM ASCA Tree and Plant Appraisal Qualified ISA Tree Risk Assessor Qualified Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 12 Attachment 1. Aerial Photo of Harmony Ridge Plat Project (2019 King County iMap) Project Area Boundary Forest Cover Type Boundary Type I Type II Off-site Utility Extension Area Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 13 Attachment 2. Harmony Ridge Plat Site Plan Project Area Boundary Tree Protection Fence Locations Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 14 Project Area Boundary Tree Protection Fence Locations Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 15 Project Area Boundary Tree Protection Fence Locations Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 16 Project Area Boundary Tree Protection Fence Locations Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 17 Project Area Boundary Tree Protection Fence Locations Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 18 Attachment 3. List of Trees in Tree Tracts on the Harmony Ridge Plat Project Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 550635 Bigleaf Maple 10,11 Fair 28 Yes 11 Remove Church 550639 Bigleaf Maple 24 Good 30 Yes 18 Save 9 Church 550644 Western Redcedar 20 Fair 10 Yes 15 Remove 20 stems Church 551010 Raywood Ash 14 Fair 21 Yes 11 Save 6 Church 551275 Honey Locust 10 Fair 19 Yes 8 Save 5 Church 551276 Honey Locust 8 Fair 25 Yes 6 Save 4 Church 551326 Colorado Blue Spruce 12 Fair 10 Yes 9 Save 6 Church 551397 Dogwood 20 Fair 15 Yes 15 Save 8 Church 551474 Douglas-fir 26 Good 25 Yes 20 Save 10 Tract C 551475 Colorado Blue Spruce 7 Fair 8 Yes 6 Save 4 Tract C 551476 Western Redcedar 13 Fair 13 Yes 10 Save 6 Tract C 551480 Bigleaf Maple 13 Poor 26 No Remove previous top failure Tract C 551481 Bigleaf Maple 11 Fair 20 Yes 8 Save 5 Tract C 551482 Bigleaf Maple 8,8 Fair 18 Yes 8 Save 5 Tract C Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 19 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 551484 Bigleaf Maple 12 Fair 18 Yes 9 Save 6 Tract C 551488 Douglas-fir 35 Good 22 Yes 26 Save 12 Tract C 551526 Bigleaf Maple 9 Fair 18 Yes 7 Save 4 Tract C 551527 Bigleaf Maple 9 Fair 18 Yes 7 Save 4 Tract C 551586 Bigleaf Maple 23 Fair 25 Yes 17 Save 9 Church 551587 Bigleaf Maple 10 Fair 20 Yes 8 Save 5 Church 551603 Callery Pear 11 Fair 21 Yes 8 Save 5 Church 551694 Incense Cedar 7,12,12 Fair 12 Yes 14 Save 7 Church 551696 Colorado Blue Spruce 7 Fair 10 Yes 6 Save 4 Tract C 551751 Bigleaf Maple 7 Fair 23 Yes 6 Save 4 Tract C 551752 Bigleaf Maple 18 Fair 22 Yes 14 Save 7 Tract C 551753 Bigleaf Maple 8 Fair 17 Yes 6 Save 4 Tract C 551792 Bigleaf Maple 8 Fair 15 Yes 6 Save 4 Tract C 551794 Bigleaf Maple 10 Fair 18 Yes 8 Save 5 Tract C 551888 Douglas-fir 38 Fair 25 Yes 29 Remove Tract B Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 20 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 551895 Bigleaf Maple 13 Fair 11 Yes 10 Save 6 Tract B 551898 Red Alder 10,10 Dead 0 No Remove Tract B 551899 Douglas-fir 9 Fair 12 Yes 7 Save 4 Tract B 551904 Bigleaf Maple 18 Fair 25 Yes 14 Save 7 Tract B 552049 Douglas-fir 36 Fair 28 Yes 27 Save 12 Tract B 552050 Bigleaf Maple 10,20 Fair 26 Yes 17 Save 9 Tract B 552051 Red Alder 10 Fair 25 Yes 8 Save 5 leaning Tract B 552052 Bigleaf Maple 10 Fair 15 Yes 8 Save 5 Tract B 552053 Bigleaf Maple 25 Fair 25 Yes 19 Save 10 Tract B 552054 Douglas-fir 14 Fair 8 Yes 11 Save 6 Tract B 552055 Douglas-fir 12 Fair 10 Yes 9 Save 6 Tract B 552056 Douglas-fir 7 Fair 8 Yes 6 Save 4 Tract B 552057 Bigleaf Maple 10 Very Poor 0 No Remove no top, broken out Tract B 552058 Douglas-fir 14,24 Fair 25 Yes 21 Save 10 Tract B 552059 Douglas-fir 24 Fair 22 Yes 18 Save 9 Tract B 552060 Douglas-fir 10 Fair 12 Yes 8 Save 5 Tract B 552061 Bigleaf Maple 8 Fair 15 Yes 6 Save 4 Tract B 552062 Bigleaf Maple 32 Fair 30 Yes 24 Save 11 5 stems Tract B 552063 Bigleaf Maple 14 Fair 20 Yes 11 Save 6 Tract B Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 21 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 552064 Bigleaf Maple 8 Very Poor 0 No Remove no top, cut off Tract B 552065 Bigleaf Maple 8 Fair 15 Yes 6 Save 4 Tract B 552066 Bigleaf Maple 15 Fair 20 Yes 11 Save 6 Tract B 552067 Bigleaf Maple 13 Fair 20 Yes 10 Save 6 Tract B 552068 Bigleaf Maple 14 Fair 20 Yes 11 Save 6 Tract B 552069 Bigleaf Maple 10,12 Fair 22 Yes 12 Save 6 Tract B 552070 Bigleaf Maple 10 Fair 16 Yes 8 Save 5 Tract B 552071 Bigleaf Maple 8 Fair 15 Yes 6 Save 4 Tract B 552073 Bigleaf Maple 7 Fair 10 Yes 6 Remove Tract B 552076 Bigleaf Maple 28 Fair 24 Yes 21 Remove Tract B 552077 Bigleaf Maple 15 Fair 22 Yes 11 Save 6 Tract B 552078 Bigleaf Maple 8 Dead 0 No Remove Tract B 552079 Bigleaf Maple 14 Fair 22 Yes 11 Save 6 Tract B 552080 Bigleaf Maple 14 Fair 22 Yes 11 Save 6 Tract B 552081 Bigleaf Maple 15 Fair 22 Yes 11 Save 6 Tract B Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 22 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 552082 Bigleaf Maple 6 Fair 18 Yes 6 Save 4 Tract B 552083 Bigleaf Maple 6,6 Poor 18 No Remove previous top failure Tract B 552088 Bigleaf Maple 7 Fair 10 Yes 6 Save 4 Tract B 552089 Bigleaf Maple 8 Fair 10 Yes 6 Save 4 Tract B 552090 Bigleaf Maple 8 Fair 10 Yes 6 Save 4 Tract B 552091 Bigleaf Maple 9 Fair 10 Yes 7 Save 4 Tract B 552092 Bigleaf Maple 16 Fair 15 Yes Save 7 Tract B 552093 Bird Cherry 9 Fair 12 Yes 7 Save 4 Tract B 552095 Bigleaf Maple 26 Fair 28 Yes 20 Save 10 Tract B 552161 Bigleaf Maple 11 Very Good 10 Yes 11 Save 5 Lot 13 552162 Bigleaf Maple 6 Good 6 Yes 6 Save 4 Lot 13 552163 Bigleaf Maple 14 Very Good 16 Yes 14 Save 6 Lot 13 552164 Bigleaf Maple 6, 7, 11 Very Good 18 Yes 14 Save 7 Tract B 552165 Bigleaf Maple 15 Very Good 13 Yes 13 Save 6 Tract B 552166 Bigleaf Maple 6 Very Good 8 Yes 6 Save 4 Tract B Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 23 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 552167 Bigleaf Maple 8, 12 Good 10 Yes 10 Save 7 8" stem is broken off at 10 feet Lot 12 552168 Bigleaf Maple 12 Very Good 12 Yes 12 Save 6 one sided crown 20' to west Lot 12 552242 Bird Cherry 9 Poor 15 No Remove heavy ivy South Line 552247 Bird Cherry 7 Fair 20 Yes 6 Save 4 South Line 552248 Bird Cherry 6 Fair 10 Yes 6 Save 4 South Line 552249 Bird Cherry 6 Fair 15 Yes 6 Save 4 South Line 552250 Douglas-fir 24 Good 22 Yes 18 Save 9 South Line 552334 Douglas-fir 20 Good 20 Yes 15 Save 8 South Line 552340 Douglas-fir 14 Good 13 Yes 11 Remove South Line 552341 Douglas-fir 12 Good 12 Yes 9 Remove South Line 552342 Douglas-fir 13 Good 9 Yes 10 Save 6 South Line 552363 Douglas-fir 11 Good 11 Yes 8 Save 5 South Line 552397 Black Cottonwood 25 Fair 30 Yes 19 Remove South Line 552400 Black Cottonwood 28 Fair 30 Yes 21 Remove South Line 552403 Flowering Plum 8 Fair 6 Yes 6 Save 4 South Line Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 24 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment Tree Location 552446 Flowering Plum 6 Very Poor 6 No Remove South Line 552447 Black Cottonwood 32 Poor 20 No Remove poor co-dominant stems South Line 552448 Black Cottonwood 10 Poor 20 No Remove leaning over house South Line 552451 Black Cottonwood 23 Fair 18 Yes 17 Remove South Line 552491 Black Cottonwood 26 Fair 15 Yes 20 Remove South Line 552492 Flowering Plum 15 Fair 15 Yes 11 Save 6 South Line Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 25 Attachment 4. List of Trees Assessed for Harmony Ridge Off-site Utility Extension Project Assessed Tree Outside Extension Boundary Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan - Save or Remove Tree Credits Comment 8 Douglas-fir 22 Good 15 Yes 11 Save 9 no # behind fence 9 Western Redcedar 18 Good 17 Yes 9 Save 7 no # behind fence 10 Western Hemlock 20 Fair 18 Yes 10 Save 8 no # behind fence 450000 Bigleaf Maple 7 Good 15 Yes 6 Remove 4 450001 Bigleaf Maple 12 Good 20 Yes 6 Save 5 450002 Western Redcedar 16 Good 15 Yes 8 Remove 7 450003 Western Redcedar 11 Good 15 Yes 6 Remove 5 450004 Western Redcedar 19 Good 20 Yes 10 Remove 8 450005 Bigleaf Maple 18, 19, 26 Good 30 Yes 19 Remove 12 450006 Bigleaf Maple 7 Fair 20 Yes 6 Remove 4 551912 Bigleaf Maple 13 Fair 25 Yes 7 Remove 6 551913 Bigleaf Maple 12 Good 21 Yes 6 Remove 5 551914 Bigleaf Maple 8 Good 25 Yes 6 Remove 4 551918 Bigleaf Maple 14, 33 Good 36 Yes 18 Remove 12 551932 Bigleaf Maple 15 Good 25 Yes 8 Remove 6 551933 Bigleaf Maple 11 Good 30 Yes 6 Remove 5 Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 26 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan - Save or Remove Tree Credits Comment 800024 Douglas-fir 21 Fair 12 Yes 11 Remove 8 800025 Bigleaf Maple 15 Good 20 Yes 8 Remove 6 800028 Bigleaf Maple 6 Very Poor 8 No 6 Remove 4 stem decay 800030 Bigleaf Maple 13, 19 Good 25 Yes 12 Remove 9 2 stems 800036 Douglas-fir 9 Poor 15 No 6 Remove 4 Phaeolus schweinitzii fruiting body 800037 Bigleaf Maple 7 Fair 25 Yes 6 Remove 4 leans heavy to south 800042 Western Redcedar 17 Good 10 Yes 9 Remove 7 800043 Western Redcedar 12 Good 15 Yes 6 Remove 5 800044 Bigleaf Maple 24 Good 26 Yes 12 Remove 9 800046 Bigleaf Maple 11, 15 Good 25 Yes 10 Save 7 800047 Bigleaf Maple 21 Good 30 Yes 11 Remove 8 800053 Bigleaf Maple 11, 12 Good 20 Yes 8 Remove 7 800054 Bigleaf Maple 11 Good 20 Yes 6 Remove 5 800935 Black Cottonwood 32 Poor 20 No 16 Remove 11 hollow butt 800947 Red Alder 11, 13 Very Poor 10 No 9 Remove 7 dead tops, in decline 800948 Red Alder 14 Dead 0 No 7 Remove 6 800949 Cascara 5 Fair 4 Yes 6 Remove 0 800950 Bigleaf Maple 6 Fair 8 Yes 6 Remove 4 800951 Red Alder 8 Very Poor 10 No 6 Remove 4 dead tops 800952 Red Alder 8 Dead 0 No 6 Remove 4 800953 Red Alder 10 Very Poor 10 No 6 Remove 5 dead tops Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 27 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan - Save or Remove Tree Credits Comment 800956 Douglas-fir 17 Fair 18 Yes 9 Remove 7 800957 Red Alder 16 Very Poor 15 No 8 Remove 7 dead tops 800958 Western Redcedar 16 Very Good 15 Yes 8 Save 7 800961 Red Alder 14 Dead 0 No 7 Remove 6 800972 Douglas-fir 27 Good 30 Yes 14 Remove 10 800973 Douglas-fir 37 Good 35 Yes 19 Remove 13 800976 Douglas-fir 20 Good 20 Yes 10 Remove 8 800977 Bigleaf Maple 13 Good 25 Yes 7 Save 6 800981 Bigleaf Maple 7 Good 10 Yes 6 Remove 4 800982 Bigleaf Maple 12 Good 24 Yes 6 Remove 5 800984 Bigleaf Maple 8, 9 Good 26 Yes 6 Remove 6 800985 Bigleaf Maple 9 Good 25 Yes 6 Remove 4 800995 Bigleaf Maple 9 Good 15 Yes 6 Save 4 800996 Western Redcedar 9 Good 10 Yes 6 Remove 4 800997 Douglas-fir 29 Fair 25 Yes 15 Remove 11 800999 Western Redcedar 22 Good 15 Yes 11 Remove 9 801000 Western Redcedar 7 Good 10 Yes 6 Remove 4 801002 Bigleaf Maple 11, 14 Good 26 Yes 9 Remove 7 801004 Bigleaf Maple 35 Fair 40 Yes 18 Remove 12 801005 Douglas-fir 13 Poor 15 No 7 Remove 6 stem wound 801006 Douglas-fir 7 Fair 12 Yes 6 Remove 4 Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 28 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan - Save or Remove Tree Credits Comment 801007 Bigleaf Maple 10, 17 Good 30 Yes 10 Remove 8 801008 Douglas-fir 24 Good 17 Yes 12 Remove 9 801013 Bigleaf Maple 10 Good 20 Yes 6 Save 5 801014 Western Redcedar 25 Good 20 Yes 13 Save 10 801016 Bigleaf Maple 8 Good 15 Yes 6 Remove 4 801017 Douglas-fir 27 Good 16 Yes 14 Remove 10 801033 Douglas-fir 15 Good 19 Yes 8 Save 6 801036 Douglas-fir 22 Fair 20 Yes 11 Save 9 801037 Douglas-fir 35 Very Good 30 Yes 18 Save 12 801039 Bigleaf Maple 11 Fair 15 Yes 6 Remove 5 801042 Western Redcedar 15 Good 15 Yes 8 Remove 6 801043 Western Redcedar 11 Good 15 Yes 6 Remove 5 801044 Bigleaf Maple 15, 22, 22 Good 30 Yes 18 Remove 12 801045 Western Redcedar 9 Good 10 Yes 6 Remove 4 801046 Bigleaf Maple 11 Good 22 Yes 6 Save 5 801048 Douglas-fir 33 Good 25 Yes 17 Save 12 801053 Bigleaf Maple 6 Good 15 Yes 6 Save 4 801054 Western Redcedar 10 Good 10 Yes 6 Save 5 801056 Western Redcedar 7 Good 12 Yes 6 Remove 4 801057 Western Redcedar 6 Good 10 Yes 6 Remove 4 Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 29 Tree # Species DBH (in.) Condition Dripline (feet) Save Based on Condition Alone? Yes or No Minimum Tree Protection Zone (feet) Project Plan - Save or Remove Tree Credits Comment 801066 Western Redcedar 14 Very Good 15 Yes 7 Save 6 Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 30 Attachment 5. Individual Tree Rating Key for Tree Condition RATING SYMBOL DEFINITION Very Good VG • Balanced crown that is characteristic of the species • Normal lateral and terminal branch growth rates for the species and soil type • Stem sound, normal bark vigor • No root problems • No insect or disease problems • Long-term, attractive tree Good G • Crown lacking symmetry but nearly balanced • Normal lateral and terminal branch growth rates for the species and soil type • Minor twig dieback O.K. • Stem sound, normal bark vigor • No root problems • No or minor insect or disease problems – insignificant • Long-term tree Fair F • Crown lacking symmetry due to branch loss • Slow lateral and terminal branch growth rates for the species and soil type • Minor and major twig dieback – starting to decline • Stem partly unsound, slow diameter growth and low bark vigor • Minor root problems • Minor insect or disease problems • Short-term tree 10-30 years RATING SYMBOL DEFINITION Poor P • Major branch loss – unsymmetrical crown • Greatly reduced growth • Several structurally import dead or branch scaffold branches • Stem has bark loss and significant decay with poor bark vigor • Root damage • Insect or disease problems – remedy required • Short-term tree 1-10 years Very Poor VP • Lacking adequate live crown for survival and growth • Severe decline • Minor and major twig dieback • Stem unsound, bark sloughing, previous stem or large branch failures, very poor bark vigor • Severe root problems or disease • No or minor insect or disease problems • Mortality expected within the next few years Dead DEAD • Dead Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 31 Cultural Care Needs: ABBRV. ACTIVITY DESCRIPTION CC Crown Cleaning Pruning of dead, dying, diseased, damaged, or defective branches over 1/2 inch in diameter –includes removal of dead tops CT Crown Thinning Pruning of branches described in crown cleaning, plus thinning of up to 20% of the live branches over ½ inch diameter. Branch should be 1/3 to ½ the diameter of the lateral branch. Thinning should be well distributed throughout crown of tree, and should release healthy, long-term branches. RC Crown Reduction Reduction of the crown of a tree by pruning to lateral branches. Generally used to remove declining branches or to lighten end weight on long branches. CR Crown Raising Pruning of lower branches to remove deadwood or to provide ground or building clearances. RMV Remove Remove tree due to decline or hazardous conditions that cannot be mitigated by pruning. RS Remove Sprouts Remove basal sprouts from stem of tree. Rep Replace Tree is small – is in decline or dead. Replace with suitable tree species. HT Hazard Tree Tree is hazardous and cannot be mitigated by pruning. Recommendation is to remove tree. None No Work No work necessary at this time. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 32 Attachment 6. Description of Tree Evaluation Methodology The evaluation of the tree condition on this site included the visual assessment of: 1. Live-crown ratio, 2. Lateral and terminal branch growth rates, 3. Presence of dieback in minor and major scaffold branches and twigs, 4. Foliage color, 5. Stem soundness and other structural defects, 6. Visual root collar examination, 7. Presence of insect or disease problems. 8. Windfirmness if tree removal will expose this tree to failure. In cases where signs of internal defect or disease were suspected, a core sample was taken to look for stain, decay, and diameter growth rates. Also, root collars were exposed to look for the presence of root disease. In all cases, the overall appearance of the tree was considered relative to its ability to add value to either an individual lot or the entire subdivision. Also, the scale of the tree and its proximity to both proposed and existing houses was considered. Lastly, the potential for incorporation into the project design is evaluated, as well as potential site plan modifications that may allow otherwise removed tree(s) to be both saved and protected in the development. Trees that are preserved in a development must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment, and perform well in the landscape. Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be preserved in areas where damage to people or property could occur. Trees that have developed in a forest stand are adapted to the close, dense conditions found in such stands. When surrounding trees are removed during clearing and grading, the remaining trees are exposed to extremes in wind, temperature, solar radiation, which causes sunscald, and other influences. Young, vigorous trees with well-developed crowns are best able to adapt to these changing site conditions. Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 33 Attachment 7. Tree Protection Fence Detail 6 ft. Temporary Chain Link Fence NO TRESPASSING - Protected Trees Harmony Ridge Plat – Final Tree Protection Plan Washington Forestry Consultants, Inc. Page 34 Attachment 8. Assumptions and Limiting Conditions 1) Any legal description provided to the Washington Forestry Consultants, Inc. is assumed to be correct. Any titles and ownership's to any property are assumed to be good and marketable. No responsibility is assumed for matters legal in character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management. 2) It is assumed that any property is not in violation of any applicable codes, ordinances, statutes, or other governmental regulations, unless otherwise stated. 3) Care has been taken to obtain all information from reliable sources. All data has been verified insofar as possible; however, Washington Forestry Consultants, Inc. can neither guarantee nor be responsible for the accuracy of information. 4) Washington Forestry Consultants, Inc. shall not be required to give testimony or to attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services as described in the fee schedule and contract of engagement. 5) Loss or alteration of any part of this report invalidated the entire report. 6) Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. 7) Neither all or any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. -- particularly as to value conclusions, identity of Washington Forestry Consultants, Inc., or any reference to any professional society or to any initialed designation conferred upon Washington Forestry Consultants, Inc. as stated in its qualifications. 8) This report and any values expressed herein represent the opinion of Washington Forestry Consultants, Inc., and the fee is in no way contingent upon the reporting of a specified value, a stipulated result, the occurrence neither of a subsequent event, nor upon any finding in to reported. 9) Sketches, diagrams, graphs, and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys. 10) Unless expressed otherwise: 1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and 2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the tree or other plant or property in question may not arise in the future. Note: Even healthy trees can fail under normal or storm conditions. The only way to eliminate all risk is to remove all trees within reach of all targets. Annual inspections by an ISA Certified Arborist or Certified Forester will reduce the potential of tree failures. It is impossible to predict with certainty that a tree will stand or fail, or the timing of the failure. It is considered an ‘Act of God’ when a tree fails, unless it is directly felled or pushed over by man’s actions. Section 7.0 22298.001-DRNG 7.0 OTHER PERMITS Construction Stormwater General Permit: Will be submitted separately Forest Practice Permit: Will be submitted separately Building Permit – Detention Vault: Will be submitted during the next submittal Building Permit – Lock and Load Retaining Wall: In progress Building Permit – Cut Rockery Wall: In progress Section 8.0 22298.001-DRNG 8.0 ESC ANALYSIS AND DESIGN A. Erosion and Sediment Control (ESC) Plan Analysis and Design The Erosion Control plan included with the final engineering plans, prepared in accordance with the 2017 Renton Surface Water Design Manual, and standard industry practices throughout the construction process to limit the amount of sediment traveling into the downstream systems. BMPs that are proposed include a rocked construction entrance, silt fence where needed, straw mulch for the areas that reach final grade in the lot areas, V-ditched with rock check dams, sediment ponds, and hydroseeding. The site sediment basin has more than 3 acres of ground disturbance, therefore temporary sediment pond is an appropriate BMP for this project. Temporary sediment pond will be used in combination with V-Ditches for surface water control, silt fence for perimeter protection, and a stabilized construction entrance to reduce the amount of sediment transported onto paved roads by vehicles or equipment. Sediment traps, sized for 2 acres, will be used when need to accommodate construction sequencing. The temporary sediment ponds were sized per the 2022 RSWD manual, see Figure 8.0.1 – TESC Analysis for calculations. B. Stormwater Pollution Prevention and Spill (SWPPS) Plan Design A Stormwater Pollution Prevention and Spill Site Plan has been prepared for Forest Terrace subdivision as a part of the final engineering plans. This is a site-specific plan that outlines the project scope of work and presents a comprehensive plan to prevent, respond to and report spills or release to the environment. It also provides suggested locations for: • Equipment parking/maintenance areas • Chemical storage areas with secondary containment • Construction materials and construction waste storage areas • Truck wheel washout areas This plan also provides general location of erosion control measures such as silt fencing, sediment pond, construction entrance, and clearing limits. The site is generally underlain by alluvial soils. A seasonally high groundwater table will be present during the wet weather and early spring months. Potential Spill Sources or Releases Potential spill sources during construction will include materials and equipment brought on-site. Potential spill sources include fueling, lubricating oil, hydraulic oil, backhoes, bulldozers, water trucks, support trucks, lighting units, pumps, and generators. Equipment staging and maintenance areas for fueling, hazardous materials, and hazardous waste materials have been designated on the SWPPS. Construction debris will be present during demolition of the existing on-site buildings. No fuel tanks, gasoline, oils and hydraulic fuels will be stored on-site. 22298.001-DRNG Control Pollutants Pollutants other than sediment will be controlled as part of the implemented SWPPS plan. Maintenance and repair of heavy equipment and vehicles that may result in discharge or spillage of pollutants to the ground or surface water runoff will be conducted using spill prevention measures. Contaminated surfaces will be cleaned immediately following any discharge or spill incident. Spills will be reported within 24 hours. Emergency repairs may be performed on-site using temporary plastic placed beneath and, if raining, over the vehicle. Concrete truck chutes and pumps shall be washed out only into formed areas awaiting installation of concrete or asphalt. Unused concrete remaining in the truck and pump shall be returned to the originating batch plant for recycling. Hand tools including, but not limited to, screeds, shovels, rakes and trowels shall be washed off only into formed areas awaiting installation of concrete or asphalt. When no formed areas are available, wash water and leftover product shall be contained in a lined container or in a sump designed to receive the materials. Contained concrete shall be disposed of in a manner that does not violate groundwater or surface water quality standards. Recommended BMP’s include Concrete Handling (BMP C151) Spill Prevention and Containment The following is a list of BMP’s that will be used for the project. • Store and maintain equipment in a designated area. • Reduce the amount of hazardous materials and waste by substituting non-hazardous or less hazardous materials. • Use secondary containment (drain pan) to catch spills when removing or changing fluids. • Use proper equipment (pumps, funnels) to transfer fluids • Keep spill kits readily accessible. • Check incoming vehicles for leaking oil and fluids. • Transfer used fluids and oil filters to waste or recycling drums. • Inspect equipment immediately, if necessary. • Implement a preventative maintenance schedule for equipment and vehicles. • Perform fueling in designated fueling area. • Do not “top-off” tanks • Use secondary containment (drain pan) to catch spills. • Keep spill kits readily accessible, • Inspect fueling areas routinely for leaks and spills. 22298.001-DRNG • Monitor pollution prevention BMP’s and maintain records/reports of all inspections using the worksheets at the end of this section. Spill Response Response in the first 15 minutes is critical to minimize the impacts to human health and the environment and to minimize property damage and cleanup costs. The contractor will respond immediately to spills and regulated materials. Spill response equipment shall be stored in spill response kits located in a clearly marked and accessible area. The standard approach toward spill response will be as follows: • Stop operations. • Stop the source of the spill. • Use appropriate materials to absorb, berm, or cover the area to prevent further contamination. • Notify the construction manager, • Determine the method of clean up required. All methods shall comply with the state or local requirements to spill response. • Contact a cleanup response firm if necessary. Contact Personnel The designated personnel responsible for managing, implementing and maintaining this SWPPS plan include: CECL – TBD Contractor –TBD A SWPPP report has also been prepared following the Department of Ecology (Ecology) format and will be kept on-site during all construction activities. The SWPPP report includes a narrative discussion of construction BMP’s that will be implemented during construction, based on the 13 required elements as defined by Ecology. The SWPPP report also outlines inspection, monitoring, and reporting requirements to meet the requirements of the NPDES permit. See TESC plan and calculations presented below. Total Area =3.69 Acres Peak flows per WWHM analysis: Q10yr =1.53 cfs INPUT OUTPUT Required Surface Area at top of riser pipe: SA = Q10yr x 2080 = SA = (1.30 x 2080) =3182 sf Principal Spillway - Riser Pipe Q10yr = 1.3 cfs Qdesign = (Q10yr) * (1.6) = Qdesign = (1.30) * (1.6) =2.08 cfs h = 12 inches => See Riser Inflow Curve below Emergency Overflow Spillway Length (w/3:1 side slope): Q100yr = 1.91 cfs Qdesign = (Q100yr) * (1.6) = Qdesign = (1.91) * (1.6) = 3.06 cfs H = 0.4 inches (0.2 inches minimum) L = = L = =2.80 ft (6' min. length) Dewatering Orifice Diameter: h =3.5 foot riser (3.5' min.) Ao = Ao = = 0.029 sf D = (13.54)*Ao 1/2 = D = (13.54)*0.0241/2 = 2.29 inches (1 inch min.) => Ponds with berms less than 2' in height on grades < 5% can use a Type 2 MH with a birdcage. Armour the emergency overflow spillway with riprap. => The perforated tubing connected to the dewatering orifice must be at least 2" larger in diameter than the orifice. . ∗ / - 2.4*H SA(2h) / 0.6 ∗3600 ∗24 ∗32.2 / 3598(2 ∗ 3.5) / 0.6 ∗3600 ∗24 ∗32.2 / . . ∗ . / - 2.4*0.4 Figure 8.0.1 Q100=1.92 CFS 22298 Harmony Ridge Sediment Trap Peak flows per WWHM analysis: Q10yr = 0.12 cfs Required Surface Area at invert of weir: SA = (2) * (Q10yr)= (2) * (0.45) = 250.00 sf (0.00096)(0.00096) Basic Sediment Trap Geometry: - SA at top of weir (at elevation xxx.00) = xxx sf - Minimum 3.5' deep trap requirement is met (top of weir to bottom) - Maximum 3:1 interior side slope requirement is met - 1' freeboard requirement is met (top of weir to crest of overflow spillway) - Flat bottom requirement is met - Minimum 6' wide overflow spillway requirement is met - 1' deep overflow spillway requirement is met - Overflow spillway rip rap armorment requirement is met Sediment Trap -0.3 AC WWHM2012 PROJECT REPORT HARMONY RIDGE - SEDIMENT POND/TRAP 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 2 General Model Information WWHM2012 Project Name:22298-WWHM-TESC Site Name:Harmony Ridge Site Address: City: Report Date:8/1/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 3 Landuse Basin Data Predeveloped Land Use Sediment Pond Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 3.69 Pervious Total 3.69 Impervious Land Use acre Impervious Total 0 Basin Total 3.69 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 4 Ex Builing Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.09 Impervious Total 0.09 Basin Total 0.09 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 5 Sediment Trap Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.3 Pervious Total 0.3 Impervious Land Use acre Impervious Total 0 Basin Total 0.3 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 6 Mitigated Land Use Sediment Pond Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.34 Pervious Total 1.34 Impervious Land Use acre ROADS FLAT 2.35 Impervious Total 2.35 Basin Total 3.69 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 7 Ex Builing Bypass:No GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROOF TOPS FLAT 0.09 Impervious Total 0.09 Basin Total 0.09 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 8 Sediment Trap Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.11 Pervious Total 0.11 Impervious Land Use acre ROADS FLAT 0.19 Impervious Total 0.19 Basin Total 0.3 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 9 Routing Elements Predeveloped Routing 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 10 Mitigated Routing 22298-WWHM-TESC 8/1/2025 12:44:45 PM Page 11 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:3.69 Total Impervious Area:0.09 Mitigated Landuse Totals for POC #1 Total Pervious Area:1.34 Total Impervious Area:2.44 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.123447 5 year 0.191546 10 year 0.239805 25 year 0.303607 50 year 0.352873 100 year 0.403438 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.01677 5 year 1.319537 10 year 1.529575 25 year 1.806518 50 year 2.021548 100 year 2.244292 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.149 1.399 1950 0.167 1.333 1951 0.256 0.870 1952 0.093 0.684 1953 0.073 0.740 1954 0.102 0.829 1955 0.165 0.919 1956 0.142 0.910 1957 0.126 1.085 1958 0.119 0.820 SEDIMENT POND 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 12 1959 0.100 0.789 1960 0.190 0.903 1961 0.099 0.912 1962 0.066 0.741 1963 0.088 0.883 1964 0.122 0.822 1965 0.091 1.132 1966 0.084 0.707 1967 0.184 1.257 1968 0.115 1.408 1969 0.111 1.028 1970 0.094 0.950 1971 0.111 1.134 1972 0.193 1.281 1973 0.093 0.647 1974 0.104 1.062 1975 0.154 1.096 1976 0.110 0.821 1977 0.035 0.794 1978 0.092 1.000 1979 0.053 1.349 1980 0.211 1.457 1981 0.085 1.049 1982 0.178 1.542 1983 0.133 1.164 1984 0.087 0.767 1985 0.050 1.053 1986 0.206 0.882 1987 0.191 1.340 1988 0.077 0.787 1989 0.055 0.984 1990 0.409 2.162 1991 0.235 1.639 1992 0.104 0.760 1993 0.094 0.633 1994 0.041 0.657 1995 0.129 0.922 1996 0.284 1.079 1997 0.232 1.021 1998 0.075 0.947 1999 0.241 2.114 2000 0.101 1.017 2001 0.040 1.036 2002 0.115 1.380 2003 0.151 1.073 2004 0.184 1.958 2005 0.137 0.900 2006 0.149 0.813 2007 0.308 1.933 2008 0.370 1.609 2009 0.197 1.206 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.4089 2.1616 2 0.3701 2.1140 3 0.3076 1.9576 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 13 4 0.2843 1.9330 5 0.2564 1.6390 6 0.2412 1.6088 7 0.2351 1.5419 8 0.2324 1.4567 9 0.2106 1.4084 10 0.2057 1.3993 11 0.1966 1.3802 12 0.1934 1.3494 13 0.1914 1.3400 14 0.1901 1.3330 15 0.1840 1.2815 16 0.1839 1.2575 17 0.1777 1.2061 18 0.1669 1.1640 19 0.1650 1.1344 20 0.1541 1.1320 21 0.1510 1.0963 22 0.1493 1.0855 23 0.1489 1.0789 24 0.1418 1.0729 25 0.1369 1.0624 26 0.1330 1.0534 27 0.1291 1.0494 28 0.1258 1.0360 29 0.1222 1.0280 30 0.1189 1.0209 31 0.1153 1.0174 32 0.1148 1.0001 33 0.1108 0.9844 34 0.1105 0.9501 35 0.1102 0.9466 36 0.1043 0.9222 37 0.1036 0.9190 38 0.1019 0.9116 39 0.1006 0.9100 40 0.0998 0.9033 41 0.0992 0.8999 42 0.0942 0.8827 43 0.0938 0.8825 44 0.0929 0.8700 45 0.0929 0.8287 46 0.0918 0.8217 47 0.0908 0.8212 48 0.0883 0.8201 49 0.0867 0.8131 50 0.0849 0.7936 51 0.0843 0.7889 52 0.0769 0.7872 53 0.0748 0.7668 54 0.0734 0.7598 55 0.0665 0.7411 56 0.0547 0.7398 57 0.0533 0.7069 58 0.0501 0.6844 59 0.0412 0.6569 60 0.0397 0.6467 61 0.0348 0.6328 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 14 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 15 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0617 14818 103158 696 Fail 0.0647 13394 98987 739 Fail 0.0676 12091 95137 786 Fail 0.0705 10923 91565 838 Fail 0.0735 9858 87972 892 Fail 0.0764 8953 84550 944 Fail 0.0794 8162 81406 997 Fail 0.0823 7448 78390 1052 Fail 0.0853 6791 75545 1112 Fail 0.0882 6184 72872 1178 Fail 0.0911 5698 70326 1234 Fail 0.0941 5221 67845 1299 Fail 0.0970 4810 65535 1362 Fail 0.1000 4442 63204 1422 Fail 0.1029 4109 61108 1487 Fail 0.1058 3784 59033 1560 Fail 0.1088 3478 57023 1639 Fail 0.1117 3230 55076 1705 Fail 0.1147 2990 53258 1781 Fail 0.1176 2766 51461 1860 Fail 0.1205 2565 49772 1940 Fail 0.1235 2366 48189 2036 Fail 0.1264 2152 46499 2160 Fail 0.1294 1981 45045 2273 Fail 0.1323 1826 43590 2387 Fail 0.1352 1674 42200 2520 Fail 0.1382 1542 40810 2646 Fail 0.1411 1420 39462 2779 Fail 0.1441 1300 38200 2938 Fail 0.1470 1189 36938 3106 Fail 0.1500 1103 35805 3246 Fail 0.1529 1024 34693 3387 Fail 0.1558 952 33580 3527 Fail 0.1588 897 32532 3626 Fail 0.1617 839 31527 3757 Fail 0.1647 785 30565 3893 Fail 0.1676 737 29645 4022 Fail 0.1705 686 28747 4190 Fail 0.1735 640 27891 4357 Fail 0.1764 581 27057 4656 Fail 0.1794 533 26265 4927 Fail 0.1823 484 25389 5245 Fail 0.1852 448 24661 5504 Fail 0.1882 403 23934 5938 Fail 0.1911 360 23207 6446 Fail 0.1941 330 22501 6818 Fail 0.1970 297 21817 7345 Fail 0.1999 269 21179 7873 Fail 0.2029 241 20570 8535 Fail 0.2058 217 19969 9202 Fail 0.2088 199 19400 9748 Fail 0.2117 168 18816 11200 Fail 0.2147 150 18305 12203 Fail 0.2176 132 17802 13486 Fail 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 16 0.2205 121 17297 14295 Fail 0.2235 105 16809 16008 Fail 0.2264 96 16332 17012 Fail 0.2294 86 15864 18446 Fail 0.2323 76 15411 20277 Fail 0.2352 62 14946 24106 Fail 0.2382 57 14557 25538 Fail 0.2411 48 14209 29602 Fail 0.2441 40 13830 34575 Fail 0.2470 35 13464 38468 Fail 0.2499 30 13120 43733 Fail 0.2529 28 12767 45596 Fail 0.2558 23 12414 53973 Fail 0.2588 18 12098 67211 Fail 0.2617 16 11745 73406 Fail 0.2646 13 11428 87907 Fail 0.2676 12 11139 92825 Fail 0.2705 11 10812 98290 Fail 0.2735 10 10540 105400 Fail 0.2764 9 10254 113933 Fail 0.2794 8 9995 124937 Fail 0.2823 8 9775 122187 Fail 0.2852 7 9518 135971 Fail 0.2882 6 9285 154750 Fail 0.2911 6 9065 151083 Fail 0.2941 6 8836 147266 Fail 0.2970 5 8609 172180 Fail 0.2999 5 8374 167480 Fail 0.3029 5 8183 163660 Fail 0.3058 4 7976 199400 Fail 0.3088 3 7768 258933 Fail 0.3117 3 7574 252466 Fail 0.3146 3 7388 246266 Fail 0.3176 3 7195 239833 Fail 0.3205 3 7018 233933 Fail 0.3235 3 6836 227866 Fail 0.3264 3 6667 222233 Fail 0.3293 3 6509 216966 Fail 0.3323 3 6355 211833 Fail 0.3352 3 6192 206400 Fail 0.3382 2 6015 300750 Fail 0.3411 2 5858 292900 Fail 0.3441 2 5707 285350 Fail 0.3470 2 5570 278500 Fail 0.3499 2 5443 272150 Fail 0.3529 2 5307 265350 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. 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 17 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. 22298-WWHM-TESC 8/1/2025 12:45:08 PM Page 18 LID Report 22298-WWHM-TESC 8/1/2025 12:45:33 PM Page 19 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.3 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.11 Total Impervious Area:0.19 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.00882 5 year 0.013853 10 year 0.016704 25 year 0.019726 50 year 0.021595 100 year 0.023186 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.079562 5 year 0.103432 10 year 0.120013 25 year 0.141899 50 year 0.158907 100 year 0.176538 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.009 0.110 1950 0.011 0.104 1951 0.019 0.068 1952 0.006 0.053 1953 0.005 0.058 1954 0.008 0.065 1955 0.012 0.072 1956 0.010 0.071 1957 0.008 0.085 1958 0.009 0.064 1959 0.008 0.061 SEDIMENT TRAP 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 20 1960 0.013 0.071 1961 0.007 0.071 1962 0.005 0.058 1963 0.006 0.069 1964 0.008 0.064 1965 0.006 0.089 1966 0.006 0.055 1967 0.012 0.099 1968 0.007 0.110 1969 0.007 0.081 1970 0.006 0.074 1971 0.006 0.089 1972 0.014 0.101 1973 0.007 0.050 1974 0.007 0.083 1975 0.010 0.086 1976 0.007 0.064 1977 0.001 0.062 1978 0.006 0.078 1979 0.004 0.105 1980 0.014 0.115 1981 0.005 0.082 1982 0.011 0.121 1983 0.009 0.091 1984 0.006 0.060 1985 0.003 0.082 1986 0.015 0.069 1987 0.014 0.105 1988 0.005 0.061 1989 0.003 0.077 1990 0.028 0.170 1991 0.017 0.129 1992 0.007 0.059 1993 0.007 0.049 1994 0.002 0.051 1995 0.010 0.072 1996 0.021 0.085 1997 0.017 0.080 1998 0.004 0.074 1999 0.016 0.166 2000 0.007 0.080 2001 0.001 0.081 2002 0.007 0.108 2003 0.010 0.084 2004 0.012 0.153 2005 0.009 0.071 2006 0.010 0.064 2007 0.021 0.153 2008 0.027 0.127 2009 0.013 0.094 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0283 0.1704 2 0.0271 0.1657 3 0.0210 0.1534 4 0.0207 0.1525 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 21 5 0.0194 0.1290 6 0.0173 0.1266 7 0.0170 0.1211 8 0.0162 0.1146 9 0.0153 0.1102 10 0.0145 0.1098 11 0.0137 0.1083 12 0.0135 0.1052 13 0.0133 0.1045 14 0.0131 0.1039 15 0.0123 0.1007 16 0.0121 0.0990 17 0.0120 0.0939 18 0.0108 0.0908 19 0.0105 0.0888 20 0.0104 0.0888 21 0.0098 0.0860 22 0.0097 0.0851 23 0.0096 0.0847 24 0.0095 0.0842 25 0.0094 0.0832 26 0.0089 0.0824 27 0.0088 0.0820 28 0.0087 0.0808 29 0.0083 0.0806 30 0.0078 0.0800 31 0.0076 0.0796 32 0.0075 0.0781 33 0.0075 0.0767 34 0.0075 0.0743 35 0.0074 0.0739 36 0.0073 0.0721 37 0.0071 0.0718 38 0.0070 0.0714 39 0.0068 0.0711 40 0.0068 0.0709 41 0.0066 0.0705 42 0.0066 0.0692 43 0.0065 0.0691 44 0.0063 0.0682 45 0.0061 0.0648 46 0.0061 0.0643 47 0.0060 0.0643 48 0.0060 0.0641 49 0.0058 0.0638 50 0.0057 0.0618 51 0.0055 0.0614 52 0.0053 0.0613 53 0.0050 0.0600 54 0.0046 0.0594 55 0.0039 0.0578 56 0.0037 0.0577 57 0.0035 0.0552 58 0.0035 0.0534 59 0.0023 0.0511 60 0.0012 0.0504 61 0.0008 0.0494 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 22 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 23 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0044 17547 111906 637 Fail 0.0046 16164 108377 670 Fail 0.0048 14964 104998 701 Fail 0.0049 13854 101768 734 Fail 0.0051 12814 98624 769 Fail 0.0053 11813 95715 810 Fail 0.0055 10900 92913 852 Fail 0.0056 10119 90261 891 Fail 0.0058 9383 87502 932 Fail 0.0060 8731 84892 972 Fail 0.0061 8147 82518 1012 Fail 0.0063 7593 80251 1056 Fail 0.0065 7058 77898 1103 Fail 0.0067 6590 75759 1149 Fail 0.0068 6145 73706 1199 Fail 0.0070 5777 71759 1242 Fail 0.0072 5431 69834 1285 Fail 0.0074 5099 67952 1332 Fail 0.0075 4808 66198 1376 Fail 0.0077 4524 64444 1424 Fail 0.0079 4252 62712 1474 Fail 0.0081 4017 61108 1521 Fail 0.0082 3784 59589 1574 Fail 0.0084 3546 58006 1635 Fail 0.0086 3337 56509 1693 Fail 0.0087 3138 55055 1754 Fail 0.0089 2950 53686 1819 Fail 0.0091 2785 52338 1879 Fail 0.0093 2599 50991 1961 Fail 0.0094 2447 49708 2031 Fail 0.0096 2304 48510 2105 Fail 0.0098 2160 47205 2185 Fail 0.0100 2026 46071 2273 Fail 0.0101 1906 45002 2361 Fail 0.0103 1790 43868 2450 Fail 0.0105 1693 42820 2529 Fail 0.0107 1594 41815 2623 Fail 0.0108 1483 40703 2744 Fail 0.0110 1383 39719 2871 Fail 0.0112 1295 38735 2991 Fail 0.0114 1221 37773 3093 Fail 0.0115 1156 36832 3186 Fail 0.0117 1098 35933 3272 Fail 0.0119 1049 35120 3347 Fail 0.0120 998 34329 3439 Fail 0.0122 930 33452 3596 Fail 0.0124 884 32661 3694 Fail 0.0126 840 31912 3799 Fail 0.0127 789 31163 3949 Fail 0.0129 743 30436 4096 Fail 0.0131 718 29730 4140 Fail 0.0133 669 29046 4341 Fail 0.0134 633 28404 4487 Fail 0.0136 595 27720 4658 Fail 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 24 0.0138 567 27100 4779 Fail 0.0140 540 26501 4907 Fail 0.0141 496 25859 5213 Fail 0.0143 473 25239 5335 Fail 0.0145 437 24661 5643 Fail 0.0147 399 24105 6041 Fail 0.0148 369 23592 6393 Fail 0.0150 348 23014 6613 Fail 0.0152 323 22501 6966 Fail 0.0153 296 21988 7428 Fail 0.0155 274 21539 7860 Fail 0.0157 256 21027 8213 Fail 0.0159 235 20565 8751 Fail 0.0160 217 20105 9264 Fail 0.0162 197 19678 9988 Fail 0.0164 180 19252 10695 Fail 0.0166 158 18809 11904 Fail 0.0167 145 18407 12694 Fail 0.0169 130 18031 13870 Fail 0.0171 119 17639 14822 Fail 0.0173 109 17280 15853 Fail 0.0174 97 16910 17432 Fail 0.0176 91 16514 18147 Fail 0.0178 82 16178 19729 Fail 0.0179 76 15836 20836 Fail 0.0181 69 15464 22411 Fail 0.0183 61 15145 24827 Fail 0.0185 54 14818 27440 Fail 0.0186 48 14523 30256 Fail 0.0188 41 14264 34790 Fail 0.0190 38 13975 36776 Fail 0.0192 33 13697 41506 Fail 0.0193 27 13434 49755 Fail 0.0195 22 13154 59790 Fail 0.0197 21 12880 61333 Fail 0.0199 20 12637 63184 Fail 0.0200 19 12358 65042 Fail 0.0202 17 12117 71276 Fail 0.0204 14 11873 84807 Fail 0.0206 12 11608 96733 Fail 0.0207 9 11392 126577 Fail 0.0209 4 11148 278700 Fail 0.0211 3 10893 363100 Fail 0.0212 3 10677 355900 Fail 0.0214 3 10478 349266 Fail 0.0216 3 10273 342433 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. 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 25 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. 22298-WWHM-TESC 8/1/2025 12:45:57 PM Page 26 LID Report 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 27 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. 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 28 Appendix Predeveloped Schematic 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 29 Mitigated Schematic 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 30 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 22298-WWHM-TESC.wdm MESSU 25 Pre22298-WWHM-TESC.MES 27 Pre22298-WWHM-TESC.L61 28 Pre22298-WWHM-TESC.L62 30 POC22298-WWHM-TESC1.dat 31 POC22298-WWHM-TESC2.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 IMPLND 4 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Sediment Pond MAX 1 2 30 9 2 Sediment Trap MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 31 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 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 *** 4 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 END IWAT-PARM2 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 32 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Sediment Pond*** PERLND 10 3.69 COPY 501 12 PERLND 10 3.69 COPY 501 13 Ex Builing*** IMPLND 4 0.09 COPY 501 15 Sediment Trap*** PERLND 10 0.3 COPY 502 12 PERLND 10 0.3 COPY 502 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 48.4 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 33 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 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 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 34 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 22298-WWHM-TESC.wdm MESSU 25 Mit22298-WWHM-TESC.MES 27 Mit22298-WWHM-TESC.L61 28 Mit22298-WWHM-TESC.L62 30 POC22298-WWHM-TESC1.dat 31 POC22298-WWHM-TESC2.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 4 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Sediment Pond MAX 1 2 30 9 2 Sediment Trap MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 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 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 35 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 4 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 4 0 0 0 0 0 END IWAT-PARM1 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 36 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 4 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Sediment Pond*** PERLND 16 1.34 COPY 501 12 PERLND 16 1.34 COPY 501 13 IMPLND 1 2.35 COPY 501 15 Ex Builing*** IMPLND 4 0.09 COPY 501 15 Sediment Trap*** PERLND 16 0.11 COPY 502 12 PERLND 16 0.11 COPY 502 13 IMPLND 1 0.19 COPY 502 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 <-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 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 37 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 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 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 38 Predeveloped HSPF Message File 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 39 Mitigated HSPF Message File 22298-WWHM-TESC 8/1/2025 12:45:58 PM Page 40 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. 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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 Section 9.0 22298.001-DRNG 9.0 BOND QUANTITIES AND FACILITY SUMMARIES Figure 9.0.1 – Bond Quality Worksheet 1055 South Grady Way – 6 th 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: SITE IMPROVEMENT BOND QUANTITY WORKSHEET PROJECT INFORMATION CITY OF RENTON CITY OF RENTON Engineer Stamp Required (all cost estimates must have original wet stamp and signature) Clearing and Grading Utility Providers TBD Project Location and Description Project Owner Information Harmony Ridge Bellevue, WA 98007 202305-9067 Ichijo USA CO., LTD 425-497-0616 9/4/2025 Prepared by: FOR APPROVALProject Phase 1 Tskoda@barghausen.com Trenton Skoda 20100241 Barghausen Consultant Engineers 18215 72nd Ave S 4252516222 15509 116th Ave SE 1406 140th Pl NE, Suite 104 Northwest of 116th Ave SE & SE 157th St 510,192.65$ Abbreviated Legal Description: Total Estimated Construction Costs E A + B + C + D 2,882,387.18$ Estimated Civil Construction Permit - Construction Costs2 Stormwater (Drainage)C 1,078,235.44$ 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 1,207,428.73$ Water A 86,530.35$ Wastewater (Sanitary Sewer)B Page 1 of 14 Ref 8-H Bond Quantity Worksheet SECTION I PROJECT INFORMATION Version 4/1/2024 Printed 9/4/2025 Figure 9.0.1 10.3%2 All prices include labor, equipment, materials, overhead, profit, and taxes. City of Renton Sales Tax is: 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 Page 2 of 14 Ref 8-H Bond Quantity Worksheet SECTION I PROJECT INFORMATION Version 4/1/2024 Printed 9/4/2025 CED Permit #: 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 24 2,160.00 Catch Basin Protection ESC-3 145.00$ Each 5 725.00 Crushed surfacing 1 1/4" minus ESC-4 WSDOT 9-03.9(3)110.00$ CY Ditching ESC-5 10.50$ CY Excavation-bulk ESC-6 2.30$ CY Fence, silt ESC-7 SWDM 5.4.3.1 5.00$ LF 3000 15,000.00 Fence, Temporary (NGPE)ESC-8 1.75$ LF 200 350.00 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 16700 15,030.00 Interceptor Swale / Dike ESC-12 1.15$ LF 1860 2,139.00 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 16700 48,430.00 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 320 6,560.00 Plastic covering, 6mm thick, sandbagged ESC-20 SWDM 5.4.2.3 4.60$ SY 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 1 3,675.00 Sediment pond riser assembly ESC-24 SWDM 5.4.5.2 2,525.00$ Each 1 2,525.00 Sediment trap, 5' high berm ESC-25 SWDM 5.4.5.1 22.00$ LF 140 3,080.00 Sed. trap, 5' high, riprapped spillway berm section ESC-26 SWDM 5.4.5.1 80.00$ LF 10 800.00 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 300 37,500.00 Water truck, dust control ESC-31 SWDM 5.4.7 160.00$ HR 300 48,000.00 Unit Reference #Price Unit Quantity Cost EROSION/SEDIMENT SUBTOTAL:185,974.00 SALES TAX @ 10.3%19,155.32 EROSION/SEDIMENT TOTAL:205,129.32 (A) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR EROSION & SEDIMENT CONTROL Description No. (A) WRITE-IN-ITEMS Page 3 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.a EROSION_CONTROL Version: 4/01/2024 Printed 9/4/2025 CED Permit #: 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 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 3 1,560.00 3 1,560.00 Clearing/Grubbing/Tree Removal GI-6 11,475.00$ Acre 0.35 4,016.25 2.8 32,130.00 2.5 28,687.50 Excavation - bulk GI-7 2.30$ CY 25000 57,500.00 1800 4,140.00 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 740 17,020.00 Fencing, chain link, gate, vinyl coated, 20' GI-12 1,600.00$ Each Fill & compact - common barrow GI-13 28.75$ CY Fill & compact - gravel base GI-14 31.00$ CY Fill & compact - screened topsoil GI-15 44.75$ CY 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 Monuments, 3' Long GI-21 1,025.00$ Each 1 1,025.00 4 4,100.00 Sensitive Areas Sign GI-22 8.00$ Each 6 48.00 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 1 2,050.00 5.3 10,865.00 Topsoil Type A (imported)GI-26 32.75$ CY Traffic control crew ( 2 flaggers )GI-27 137.75$ HR 300 41,325.00 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 2380 13,685.00 Wall, retaining, concrete GI-32 63.00$ SF 600 37,800.00 Wall, rockery GI-33 17.25$ SF 800 13,800.00 SUBTOTAL THIS PAGE:48,416.25 119,888.00 103,007.50 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) Page 4 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 2300 26,450.00 AC Removal/Disposal RI-4 40.00$ SY Barricade, Type III ( Permanent )RI-5 64.25$ LF 25 1,606.25 Guard Rail RI-6 34.50$ LF Curb & Gutter, rolled RI-7 19.50$ LF Curb & Gutter, vertical RI-8 14.25$ LF 700 9,975.00 1520 21,660.00 Curb and Gutter, demolition and disposal RI-9 20.50$ LF 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 2450 7,350.00 Sawcut, concrete, per 1" depth RI-13 5.00$ LF Sealant, asphalt RI-14 2.25$ LF Shoulder, gravel, 4" thick RI-15 17.25$ SY Sidewalk, 4" thick RI-16 43.50$ SY 1500 65,250.00 Sidewalk, 4" thick, demolition and disposal RI-17 37.00$ SY Sidewalk, 5" thick RI-18 47.00$ SY 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 1900 39,425.00 HMA Road, 2", 4" rock, First 2500 SY RI-27 32.25$ SY HMA Road, 2", 4" rock, Qty. over 2500SY RI-28 24.00$ SY HMA Road, 4", 6" rock, First 2500 SY RI-29 51.75$ SY 2500 129,375.00 HMA Road, 4", 6" rock, Qty. over 2500 SY RI-30 42.50$ SY 2500 106,250.00 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:83,200.00 324,141.25 (B)(C)(D)(E) Page 5 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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-1 250.00$ EA 42 10,500.00 227 56,750.00 Median Landscaping LA-2 Right-of-Way Landscaping LA-3 Wetland Landscaping LA-4 SUBTOTAL LANDSCAPING & VEGETATION:10,500.00 56,750.00 (B)(C)(D)(E) TRAFFIC & LIGHTING No. Signs TR-1 400.00$ EA 17 6,800.00 Street Light System ( # of Poles)TR-2 6,000.00$ EA 26 156,000.00 Traffic Signal TR-3 Traffic Signal Modification TR-4 SUBTOTAL TRAFFIC & LIGHTING:162,800.00 (B)(C)(D)(E) WRITE-IN-ITEMS SUBTOTAL WRITE-IN ITEMS: STREET AND SITE IMPROVEMENTS SUBTOTAL:131,616.25 617,329.25 159,757.50 SALES TAX @ 10.3%13,556.47 63,584.91 16,455.02 STREET AND SITE IMPROVEMENTS TOTAL:145,172.72 680,914.16 176,212.52 (B)(C)(D)(E) Page 6 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 1 103.00 Through-curb Inlet Framework D-3 460.00$ Each 1 460.00 CB Type I D-4 1,725.00$ Each 3 5,175.00 2 3,450.00 10 17,250.00 CB Type IL D-5 2,000.00$ Each CB Type II, 48" diameter D-6 3,500.00$ Each 5 17,500.00 19 66,500.00 for additional depth over 4' D-7 550.00$ FT 44 24,200.00 100 55,000.00 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 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 18 4,140.00 Culvert, PVC, 4" D-23 11.50$ LF Culvert, PVC, 6" D-24 15.00$ LF 880 13,200.00 Culvert, PVC, 8" D-25 17.00$ LF 130 2,210.00 Culvert, PVC, 12" D-26 26.00$ LF 665 17,290.00 1160 30,160.00 Culvert, PVC, 15" D-27 40.00$ LF Culvert, PVC, 18" D-28 47.00$ LF 430 20,210.00 Culvert, PVC, 24"D-29 65.00$ LF 380 24,700.00 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:64,268.00 200,480.00 36,800.00 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) Page 7 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) 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 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 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 Culvert, CPE Triple Wall, 12" D-53 27.00$ LF 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: (B)(C)(D)(E) Page 8 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) 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 Culvert, DI, 8"D-96 101.00$ LF Culvert, DI, 12"D-97 121.00$ LF 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: (B)(C)(D)(E) Page 9 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) 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 Geotextile, laid in trench, polypropylene SD-5 3.40$ SY Mid-tank Access Riser, 48" dia, 6' deep SD-6 2,300.00$ Each 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 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: (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-3 620,000.00$ Each 1 620,000.00 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 56,000.00$ Each 1 56,000.00 Bioretention Facility SF-16 Each SUBTOTAL STORMWATER FACILITIES:676,000.00 (B)(C)(D)(E) Page 10 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) 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:64,268.00 876,480.00 36,800.00 SALES TAX @ 10.3%6,619.60 90,277.44 3,790.40 DRAINAGE AND STORMWATER FACILITIES TOTAL:70,887.60 966,757.44 40,590.40 (B) (C) (D) (E) Page 11 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 1 3,400.00 Ductile Iron Watermain, CL 52, 4 Inch Diameter W-2 58.00$ LF Ductile Iron Watermain, CL 52, 6 Inch Diameter W-3 65.00$ LF Ductile Iron Watermain, CL 52, 8 Inch Diameter W-4 75.00$ LF 700 52,500.00 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 Gate Valve, 4 inch Diameter W-7 1,225.00$ Each Gate Valve, 6 inch Diameter W-8 1,350.00$ Each 3 4,050.00 Gate Valve, 8 Inch Diameter W-9 1,550.00$ Each 1 1,550.00 Gate Valve, 10 Inch Diameter W-10 2,100.00$ Each Gate Valve, 12 Inch Diameter W-11 2,500.00$ Each Fire Hydrant Assembly W-12 5,000.00$ Each 1 5,000.00 2 10,000.00 Permanent Blow-Off Assembly W-13 1,950.00$ Each 1 1,950.00 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 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 WATER SUBTOTAL:12,450.00 66,000.00 SALES TAX @ 10.3%1,282.35 6,798.00 WATER TOTAL:13,732.35 72,798.00 (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR WATER Quantity Remaining (Bond Reduction) (B)(C) Page 12 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.d WATER Version: 4/1/2024 Printed 9/4/2025 CED Permit #: 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 20 23,000.00 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 625 68,750.00 Sewer Pipe, PVC, 8 inch Diameter SS-7 120.00$ LF 520 62,400.00 1650 198,000.00 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 3 20,700.00 13 89,700.00 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:83,100.00 356,450.00 23,000.00 SALES TAX @ 10.3%8,559.30 36,714.35 2,369.00 SANITARY SEWER TOTAL:91,659.30 393,164.35 25,369.00 (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR SANITARY SEWER Quantity Remaining (Bond Reduction) (B)(C) Page 13 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.e SANITARY SEWER Version: 4/1/2024 Printed 9/4/2025 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)250,564.37$ Future Public Improvements Subtotal (c)1,146,876.51$ Stormwater & Drainage Facilities (Public & Private) Subtotal (d) (d)1,078,235.44$ (e) (f) Site Restoration Existing Right-of-Way and Storm Drainage Improvements Maintenance Bond 495,135.27$ Bond Reduction 2 Construction Permit Bond Amount 3 Minimum Bond Amount is $10,000.00 1 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering. 2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% will cover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering. * Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton. ** Note: All prices include labor, equipment, materials, overhead, profit, and taxes. 4252516222 Tskoda@barghausen.com Harmony Ridge 15509 116th Ave SE 202305-9067 FOR APPROVAL 18215 72nd Ave S 1,659,211.33$ P (a) x 100% SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS 9/4/2025 Trenton Skoda 20100241 Barghausen Consultant Engineers 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) EST1 ((b) + (c) + (d)) x 20% -$ MAINTENANCE BOND */** (after final acceptance of construction) 205,129.32$ 250,564.37$ 1,454,082.00$ 205,129.32$ -$ 1,078,235.44$ -$ Page 14 of 14 Ref 8-H Bond Quantity Worksheet SECTION III. BOND WORKSHEET Version: 4/1/2024 Printed 9/4/2025 Section 10.0 22298.001-DRNG 10.0 OPERATIONS AND MAINTENANCE MANUAL The City will own and maintain the public drainage facility for this project. An Operations and Maintenance Manual is not required for publicly maintained facilities.