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Home My WebLink AboutEx_09_TIR PRELIMINARY TECHNICAL INFORMATION REPORT Harmony Ridge 15509 116th Ave SE Renton, Washington Prepared for: Ichijo USA Co., Ltd. 1406 140th PL NE, Suite 104 Bellevue, WA 98007 February 2, 2023 Our Job No. 22298 2/2/2023 RECEIVED 05/03/2023 AMorganroth PLANNING DIVISION DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.002-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 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 – Detention Vault Calculations 4.5 Water Quality System 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 6.1 Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. dated November 22, 2022 7.0 OTHER PERMITS 8.0 ESC ANALYSIS AND DESIGN 9.0 BOND QUANTITIES AND FACILITY SUMMARIES 10.0 OPERATIONS AND MAINTENANCE MANUAL DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 1.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 1.0 PROJECT OVERVIEW The Harmony Ridge project is a single-family residential project consisting of the redevelopment of an existing parcel in the City of Renton. The project includes approximately 6.2 acres of parcel area located on 15509 116th Ave SE. The proposed development will construct 21 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 and Alderwood material with 8 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. Stormwater runoff generated by the onsite impervious and pervious areas will be routed to an onsite detention vault located within the 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 located immediately downstream of the proposed detention vault. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 Keystone Wall Figure 1.0.1DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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: Reduced Impervious Surface, Basic Sheet Flow Dispersion N/A N/A N/A DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 tributary to Ginger Creek Sub Basin 1 12/01/2022 Flow Control Duration Standard Matching Forested Site Conditions TBD TBD TBD DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 Reduced Impervious Surface Roof Downspout Connections DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 2/2/2023 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Horizontal: Scale: Vertical: For: Title: V I C I N I T Y M A P Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 vmap.cdr RE FER ENC E: MapQuest (2022) SITE Figure 1.0.2DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 For:Title: 22298 1 ICHIJO USA CO., LTD. 1406 140TH PL NE, SUITE 104 BELLEVUE, WA 98007 HARMONY RIDGECITY OF RENTON, KING COUNTY, WASHINGTONA PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M.HARMONY RIDGE FORPREDEVELOPED BASIN MAPPREDEVELOPED BASIN MAP FOR 1 SCALE: 1"=50'116TH AVE SESE 19TH STSE 19TH STPREDEVELOPEDBASIN 1PREDEVELOPED BASIN 1PREDEVELOPED BASIN 2PREDEVELOPEDBASIN 1PREDEVELOPEDBASIN 1PREDEVELOPEDBASIN 2Figure 1.0.3DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Horizontal: Scale: Vertical: For: Title: S O I L S U RV E Y M A P Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 soil.cdr HS G B B/D RE FER ENCE: US DA, Natural Resources Conservation Service LE GEN D: SITE AgC = Alderwood gravelly sandy loam, 8-15% slopes AmC = Arents, Alderwood material, 6-15% slopes Figure 1.0.4DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Horizontal: Scale: Vertical: For: Title: A S S E S S O R M A P 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 RE FER ENC E: King County Department of Assessments (July 2022) Figure 1.0.5DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Horizontal: Scale: Vertical: For: Title: F E M A M A P Job Number N.T.S.N/A 22298 DATE: 11/14/22 Harmony Ridge Renton, Washington P:\22000s\22298\exhibit\graphics\22298 fema.cdr REFER EN CE: Federal Emergency Management Agency (Portion of Map 53033C0979G, Aug. 2020) SITE L E GEND Areas determined to be outside the 0.2% annual chance floodplain.ZONE X OTHER AREAS Figure 1.0.6 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Horizontal: Scale: Vertical: For: Title: S E N S I T I V E A R E A S M A P 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 RE FER ENC E: King County iM AP (2022) Figure 1.0.7DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 NO PARKINGNO PARKING FIRE LANE12345678910111218171615141320211922For:Title: 22298 1 ICHIJO USA CO., LTD. 1406 140TH PL NE, SUITE 104 BELLEVUE, WA 98007 HARMONY RIDGECITY OF RENTON, KING COUNTY, WASHINGTONA PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M.HARMONY RIDGE FORDEVELOPED BASIN MAPDEVELOPED BASIN MAP FOR 1 SCALE: 1"=50'116TH AVE SESE 19TH STSE 19TH STDEVELOPED BASIN 1DEVELOPED BASIN 2TRACT ATRACT BTRACT DDETENTIONVAULTROAD AROAD B DEVELOPEDBASIN 1DEVELOPEDBASIN 2PUGET DR SE DEVELOPEDBASIN 1DEVELOPEDBASIN 1TRACT CFigure 1.0.8DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 SDSD SD SD SDSD SD SD SDSDSDSDSDSDFor:Title: 22298 1 ICHIJO USA CO., LTD. 1406 140TH PL NE, SUITE 104 BELLEVUE, WA 98007 HARMONY RIDGECITY OF RENTON, KING COUNTY, WASHINGTONA PORTION OF SECTION 20, TOWNSHIP 23 N., RANGE 05 E., W.M.HARMONY RIDGE FORDOWNSTREAM BASIN MAPDOWNSTREAM BASIN MAP FOR 1 SCALE: 1"=100'DEVELOPEDBASIN 2FLOWPATH LEGENDSDSPECIAL NOTE1/4 MILE DOWNSTREAMFROM SITESE 157TH ST116TH AVE SESE 19TH STPUGET DR SEABERDEEN AVE SE C AM A S C T S E ROLLING HILLS AVE SESE 18TH CTSE 17TH CTSE 18TH PLRO Y A L H I L S D R S E 116TH AVE SE SE 1 6 TH S T FERNDALE AVE SEDEVELOPEDBASIN 11/4 MILE DOWNSTREAMFROM SITETHUNDER HILLSCREEKSE 19TH STDEVELOPEDBASIN 1Figure 1.0.9DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 2.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 sheetflows 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 smaller portion of the site consisting of the existing church buildings, parking lot and frontage improvements on the north side of the site flows to the northeast and is tributary to the Ginger Creek sub basin. 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 tributary to the Ginger Creek sub basin as discussed above will continue to be collected by the existing conveyance system on 116th Ave SE and discharging to the Ginger Creek sub basin. Please refer to the Predeveloped and Developed 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 the developed site is designed to be collected and detained per Flow Control Duration Standard Matching Forested Site Conditions. No. 4: Conveyance System The conveyance system will be designed per the 2022 City of Renton Surface Water Design Manual and will be included in Section 5.0 of the Technical Information Report at final engineering. 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 An Operations and Maintenance Manual, if required, will be provided at final engineering. No. 7: Bonds and Liability Bonding will be completed as required by the City of Renton at final engineering. No. 8: Water Quality Basic Water Quality will be provided using a Stormfilter system. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG No. 9: Flow Control 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 BMP’s are infeasible for the lots and roads: Full Infiltration, Limited Infiltration, Bioretention and Permeable Pavement. Full Dispersion cannot be applied as a native vegetated flowpath cannot be provided due to site constraints. As such, the Reduced Impervious Surface Credit BMP and the Basic Sheet Flow Dispersion BMP will be applied where feasible for each lot to meet the 2022 CORSWDM requirements. Further detail on the application of these BMP’s for each lot will be addressed during final engineering. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 3.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG TASK 1 – STUDY AREA DEFINITION AND MAPS The Harmony Ridge project consists of the development of 21 single-family lots in a 6.2 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 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 the downstream system. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 sheetflows 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 flowpath. 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 installing a new catch basin along the culvert 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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. 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 flowpath. The locations of each of these photos are shown in the Downstream Basin Map (Figure 1.0.9) included in this report. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 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. Photo #3 – Looking Northeast Photo #4 – Looking Northeast DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 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 manhole shown in Photo #5. After another 310 feet of flowpath to the northeast runoff reaches one- quarter downstream just before discharging into the manhole shown in Photo #6. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 4.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 (5.29 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 area because rooftop runoff from this building discharges to the forested area onsite and sheetflows 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. A smaller portion of the existing site flows towards 116th Ave SE and is tributary to the Ginger Creek sub basin to the northeast. This area is approximately 1.2 acres in size and consists of three UCC buildings and a parking lot. The parking lot was confirmed to flow towards 116th Ave SE due to the relative elevations of the parking lot shown in the topographic survey. Based on the invert elevations of the adjacent yard drains and a field reconnaissance conducted on January 18th, it can be reasonably assumed that rooftop runoff from the three UCC buildings near the northeast corner of the site flows to a nearby onsite yard drain and connects to the existing conveyance system on 116th Ave SE. The majority of this area of the site will not be disturbed with this development. The only disturbance to this area consists of the frontage improvements along 116th Ave SE that will be constructed with this development on the north side of the site. This frontage improvement area is 0.16 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 4.2 Developed Site Hydrology When completed, the Harmony Ridge project will create 21 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 two basins in the developed condition: Developed Basins 1 and 2. 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 frontage improvements on 116th Ave SE to the south of the entrance of the site. 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 near Lot 21 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 Impervious Roads Impervious Bypass Road Existing UCC building Impervious Lots Pervious Lawn Tree Protection Tracts Total Area 1.36 Ac(1) 0.09 Ac(2) 0.07 Ac 1.63 Ac(3) 1.40 Ac(4) 0.74 Ac(5) 5.29 Ac Notes: 1. Consists of 100% impervious right-of-way area, alley roads, and vault access road 2. Offsite Sewer manhole access roads 3. 65% maximum impervious coverage per lot. See Section 4.3 for further detail 4. Modeled as till grass 5. Modeled as forested 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 116th Ave SE on the north side of the site entrance (0.16 acres in size) 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 discharge 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 4.3 Performance Standards This project is subject to Core Requirement #9 of the 2022 CORSWDM requiring the application of onsite BMP’s 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 2017 CORSWDM states that the assumed impervious coverage for each lot shall not be less than 4,000 square feet per lot or the maximum impervious coverage permitted per Table 3.2.2.C, whichever is less. The largest lot size proposed for this project is 5,935 SF which results in a maximum impervious surface of 3,857 for the site. This means that the maximum lot impervious surface coverage of 65% will be used for sizing 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 due to onsite native soil being glacial till. See Geotechnical Engineering Study in Section 6.0 for further detail. Limited Infiltration Not feasible due to onsite native soil being glacial till. See Geotechnical Engineering Study in Section 6.0 for further detail. Basic Dispersion May be feasible for portions of driveways and walks depending on the specific site plan for each lot. Feasibility of this BMP will be verified during the building permit stage. Farmland Dispersion Not applicable. Bioretention Not feasible due to onsite native soil being glacial till. See Geotechnical Engineering Study in Section 6.0 for further detail. Permeable Pavement Not feasible due to onsite native soil being glacial till. See Geotechnical Engineering Study in Section 6.0 for further detail. Rainwater Harvesting Feasible but impractical, evaluated on an individual lot basis at developer’s discretion. Reduced Impervious Surface Credit Will be applied as required on each lot. Further detail will be provided during final engineering. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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. After sizing the detention vault for these standards, the volume required for the vault is 62,552 cubic feet. The volume provided for the detention pond is 64,045 cubic feet. Please see the WWHM calculations provided in this section for further detail. Developed Basin 2 As noted earlier, there is approximately 0.16 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 WWHM2012 PROJECT REPORT Figure 4.4.1 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 2 General Model Information Project Name:Detention Vault Site Name: Site Address: City: Report Date:2/1/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 3.36 C, Forest, Mod 1.93 Pervious Total 5.29 Impervious Land Use acre Impervious Total 0 Basin Total 5.29 Element Flows To: Surface Interflow Groundwater DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 1.4 C, Forest, Flat 0.74 Pervious Total 2.14 Impervious Land Use acre ROADS FLAT 1.36 ROOF TOPS FLAT 1.7 Impervious Total 3.06 Basin Total 5.2 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 5 Bypass Basin 1 Bypass:Yes GroundWater:No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS FLAT 0.09 Impervious Total 0.09 Basin Total 0.09 Element Flows To: Surface Interflow Groundwater DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 7 Mitigated Routing Vault 1 Width:64 ft. Length:64 ft. Depth:15.8 ft. Discharge Structure Riser Height:15.3 ft. Riser Diameter:18 in. Orifice 1 Diameter:1 in.Elevation:0 ft. Orifice 2 Diameter:1.32 in.Elevation:8.5 ft. Orifice 3 Diameter:1.5 in.Elevation:12 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.094 0.000 0.000 0.000 0.1756 0.094 0.016 0.011 0.000 0.3511 0.094 0.033 0.016 0.000 0.5267 0.094 0.049 0.019 0.000 0.7022 0.094 0.066 0.022 0.000 0.8778 0.094 0.082 0.025 0.000 1.0533 0.094 0.099 0.027 0.000 1.2289 0.094 0.115 0.030 0.000 1.4044 0.094 0.132 0.032 0.000 1.5800 0.094 0.148 0.034 0.000 1.7556 0.094 0.165 0.036 0.000 1.9311 0.094 0.181 0.037 0.000 2.1067 0.094 0.198 0.039 0.000 2.2822 0.094 0.214 0.041 0.000 2.4578 0.094 0.231 0.042 0.000 2.6333 0.094 0.247 0.044 0.000 2.8089 0.094 0.264 0.045 0.000 2.9844 0.094 0.280 0.046 0.000 3.1600 0.094 0.297 0.048 0.000 3.3356 0.094 0.313 0.049 0.000 3.5111 0.094 0.330 0.050 0.000 3.6867 0.094 0.346 0.052 0.000 3.8622 0.094 0.363 0.053 0.000 4.0378 0.094 0.379 0.054 0.000 4.2133 0.094 0.396 0.055 0.000 4.3889 0.094 0.412 0.056 0.000 4.5644 0.094 0.429 0.058 0.000 4.7400 0.094 0.445 0.059 0.000 4.9156 0.094 0.462 0.060 0.000 5.0911 0.094 0.478 0.061 0.000 5.2667 0.094 0.495 0.062 0.000 5.4422 0.094 0.511 0.063 0.000 5.6178 0.094 0.528 0.064 0.000 5.7933 0.094 0.544 0.065 0.000 5.9689 0.094 0.561 0.066 0.000 6.1444 0.094 0.577 0.067 0.000 6.3200 0.094 0.594 0.068 0.000 6.4956 0.094 0.610 0.069 0.000 Volume Required: 62,552 CF DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 8 6.6711 0.094 0.627 0.070 0.000 6.8467 0.094 0.643 0.071 0.000 7.0222 0.094 0.660 0.071 0.000 7.1978 0.094 0.676 0.072 0.000 7.3733 0.094 0.693 0.073 0.000 7.5489 0.094 0.709 0.074 0.000 7.7244 0.094 0.726 0.075 0.000 7.9000 0.094 0.742 0.076 0.000 8.0756 0.094 0.759 0.077 0.000 8.2511 0.094 0.775 0.077 0.000 8.4267 0.094 0.792 0.078 0.000 8.6022 0.094 0.808 0.094 0.000 8.7778 0.094 0.825 0.105 0.000 8.9533 0.094 0.841 0.113 0.000 9.1289 0.094 0.858 0.119 0.000 9.3044 0.094 0.874 0.125 0.000 9.4800 0.094 0.891 0.130 0.000 9.6556 0.094 0.907 0.135 0.000 9.8311 0.094 0.924 0.139 0.000 10.007 0.094 0.940 0.143 0.000 10.182 0.094 0.957 0.147 0.000 10.358 0.094 0.974 0.151 0.000 10.533 0.094 0.990 0.155 0.000 10.709 0.094 1.007 0.159 0.000 10.884 0.094 1.023 0.162 0.000 11.060 0.094 1.040 0.165 0.000 11.236 0.094 1.056 0.169 0.000 11.411 0.094 1.073 0.172 0.000 11.587 0.094 1.089 0.175 0.000 11.762 0.094 1.106 0.178 0.000 11.938 0.094 1.122 0.181 0.000 12.113 0.094 1.139 0.204 0.000 12.289 0.094 1.155 0.220 0.000 12.464 0.094 1.172 0.231 0.000 12.640 0.094 1.188 0.241 0.000 12.816 0.094 1.205 0.250 0.000 12.991 0.094 1.221 0.258 0.000 13.167 0.094 1.238 0.266 0.000 13.342 0.094 1.254 0.273 0.000 13.518 0.094 1.271 0.280 0.000 13.693 0.094 1.287 0.287 0.000 13.869 0.094 1.304 0.294 0.000 14.044 0.094 1.320 0.300 0.000 14.220 0.094 1.337 0.306 0.000 14.396 0.094 1.353 0.312 0.000 14.571 0.094 1.370 0.318 0.000 14.747 0.094 1.386 0.323 0.000 14.922 0.094 1.403 0.329 0.000 15.098 0.094 1.419 0.334 0.000 15.273 0.094 1.436 0.339 0.000 15.449 0.094 1.452 1.253 0.000 15.624 0.094 1.469 3.130 0.000 15.800 0.094 1.485 4.993 0.000 15.976 0.094 1.426 6.152 0.000 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:11 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:5.29 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:2.14 Total Impervious Area:3.15 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.154691 5 year 0.249196 10 year 0.307422 25 year 0.374071 50 year 0.418569 100 year 0.458886 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.114226 5 year 0.173507 10 year 0.221899 25 year 0.294743 50 year 0.358375 100 year 0.430804 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.162 0.090 1950 0.200 0.129 1951 0.343 0.303 1952 0.108 0.072 1953 0.087 0.086 1954 0.134 0.083 1955 0.214 0.086 1956 0.171 0.159 1957 0.137 0.094 1958 0.155 0.105 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:51 PM Page 10 1959 0.133 0.084 1960 0.234 0.241 1961 0.131 0.124 1962 0.081 0.065 1963 0.112 0.086 1964 0.151 0.092 1965 0.105 0.145 1966 0.101 0.083 1967 0.223 0.101 1968 0.132 0.086 1969 0.129 0.084 1970 0.106 0.082 1971 0.116 0.098 1972 0.257 0.191 1973 0.116 0.141 1974 0.127 0.098 1975 0.173 0.097 1976 0.123 0.083 1977 0.016 0.082 1978 0.108 0.121 1979 0.065 0.071 1980 0.266 0.226 1981 0.097 0.087 1982 0.191 0.199 1983 0.168 0.087 1984 0.103 0.077 1985 0.061 0.080 1986 0.270 0.151 1987 0.238 0.191 1988 0.094 0.081 1989 0.061 0.077 1990 0.525 0.259 1991 0.301 0.218 1992 0.119 0.121 1993 0.121 0.071 1994 0.041 0.066 1995 0.173 0.128 1996 0.377 0.300 1997 0.306 0.286 1998 0.071 0.087 1999 0.305 0.193 2000 0.120 0.106 2001 0.022 0.084 2002 0.132 0.151 2003 0.183 0.086 2004 0.219 0.286 2005 0.159 0.090 2006 0.184 0.150 2007 0.390 0.352 2008 0.495 0.292 2009 0.238 0.162 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.5248 0.3521 2 0.4949 0.3031 3 0.3904 0.2998 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:51 PM Page 11 4 0.3772 0.2919 5 0.3431 0.2864 6 0.3060 0.2858 7 0.3048 0.2588 8 0.3010 0.2406 9 0.2697 0.2259 10 0.2657 0.2177 11 0.2573 0.1987 12 0.2384 0.1934 13 0.2382 0.1913 14 0.2337 0.1907 15 0.2226 0.1622 16 0.2193 0.1595 17 0.2137 0.1511 18 0.1995 0.1509 19 0.1908 0.1499 20 0.1845 0.1454 21 0.1826 0.1408 22 0.1734 0.1287 23 0.1729 0.1280 24 0.1710 0.1243 25 0.1681 0.1215 26 0.1617 0.1208 27 0.1593 0.1065 28 0.1546 0.1054 29 0.1510 0.1013 30 0.1372 0.0980 31 0.1340 0.0978 32 0.1326 0.0966 33 0.1319 0.0937 34 0.1317 0.0921 35 0.1306 0.0899 36 0.1290 0.0899 37 0.1267 0.0872 38 0.1232 0.0868 39 0.1206 0.0865 40 0.1202 0.0865 41 0.1186 0.0864 42 0.1158 0.0864 43 0.1157 0.0863 44 0.1116 0.0857 45 0.1080 0.0842 46 0.1079 0.0841 47 0.1064 0.0837 48 0.1052 0.0834 49 0.1028 0.0832 50 0.1011 0.0826 51 0.0966 0.0823 52 0.0941 0.0816 53 0.0873 0.0805 54 0.0813 0.0799 55 0.0713 0.0772 56 0.0653 0.0769 57 0.0614 0.0718 58 0.0610 0.0715 59 0.0405 0.0705 60 0.0216 0.0664 61 0.0161 0.0654 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:51 PM Page 13 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0773 17935 17040 95 Pass 0.0808 16506 12211 73 Pass 0.0842 14919 10692 71 Pass 0.0877 13836 10029 72 Pass 0.0911 12478 9456 75 Pass 0.0946 11516 9137 79 Pass 0.0980 10414 8645 83 Pass 0.1015 9666 8301 85 Pass 0.1049 9007 8012 88 Pass 0.1084 8224 7593 92 Pass 0.1118 7670 7238 94 Pass 0.1153 6979 6770 97 Pass 0.1187 6511 6436 98 Pass 0.1222 5978 5976 99 Pass 0.1256 5634 5653 100 Pass 0.1290 5191 5168 99 Pass 0.1325 4883 4864 99 Pass 0.1359 4605 4588 99 Pass 0.1394 4259 4205 98 Pass 0.1428 4021 3910 97 Pass 0.1463 3705 3553 95 Pass 0.1497 3493 3320 95 Pass 0.1532 3215 2988 92 Pass 0.1566 3037 2791 91 Pass 0.1601 2802 2535 90 Pass 0.1635 2627 2344 89 Pass 0.1670 2470 2169 87 Pass 0.1704 2278 1932 84 Pass 0.1739 2147 1781 82 Pass 0.1773 1972 1525 77 Pass 0.1807 1854 1347 72 Pass 0.1842 1725 1178 68 Pass 0.1876 1626 1111 68 Pass 0.1911 1485 1044 70 Pass 0.1945 1382 1005 72 Pass 0.1980 1295 979 75 Pass 0.2014 1203 950 78 Pass 0.2049 1137 924 81 Pass 0.2083 1069 889 83 Pass 0.2118 1017 858 84 Pass 0.2152 944 810 85 Pass 0.2187 893 773 86 Pass 0.2221 828 732 88 Pass 0.2256 781 697 89 Pass 0.2290 731 665 90 Pass 0.2324 699 640 91 Pass 0.2359 653 615 94 Pass 0.2393 609 581 95 Pass 0.2428 581 552 95 Pass 0.2462 543 515 94 Pass 0.2497 500 493 98 Pass 0.2531 468 459 98 Pass 0.2566 428 435 101 Pass DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:57:51 PM Page 14 0.2600 383 386 100 Pass 0.2635 360 368 102 Pass 0.2669 341 345 101 Pass 0.2704 302 301 99 Pass 0.2738 281 278 98 Pass 0.2773 252 242 96 Pass 0.2807 233 216 92 Pass 0.2841 209 180 86 Pass 0.2876 192 155 80 Pass 0.2910 164 127 77 Pass 0.2945 148 112 75 Pass 0.2979 135 101 74 Pass 0.3014 121 84 69 Pass 0.3048 111 71 63 Pass 0.3083 96 65 67 Pass 0.3117 89 62 69 Pass 0.3152 78 57 73 Pass 0.3186 72 54 75 Pass 0.3221 66 48 72 Pass 0.3255 58 45 77 Pass 0.3290 50 42 84 Pass 0.3324 42 39 92 Pass 0.3358 38 37 97 Pass 0.3393 31 27 87 Pass 0.3427 25 20 80 Pass 0.3462 21 11 52 Pass 0.3496 20 2 10 Pass 0.3531 19 0 0 Pass 0.3565 17 0 0 Pass 0.3600 14 0 0 Pass 0.3634 12 0 0 Pass 0.3669 10 0 0 Pass 0.3703 6 0 0 Pass 0.3738 6 0 0 Pass 0.3772 6 0 0 Pass 0.3807 5 0 0 Pass 0.3841 5 0 0 Pass 0.3875 5 0 0 Pass 0.3910 4 0 0 Pass 0.3944 3 0 0 Pass 0.3979 3 0 0 Pass 0.4013 3 0 0 Pass 0.4048 3 0 0 Pass 0.4082 3 0 0 Pass 0.4117 3 0 0 Pass 0.4151 3 0 0 Pass 0.4186 3 0 0 Pass DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:35 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:35 PM Page 18 Appendix Predeveloped Schematic DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:39 PM Page 19 Mitigated Schematic DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 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 Detention Vault.wdm MESSU 25 PreDetention Vault.MES 27 PreDetention Vault.L61 28 PreDetention Vault.L62 30 POCDetention Vault1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 PERLND 11 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 11 C, Forest, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 11 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 ********* DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 21 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 11 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 11 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 11 0 4.5 0.08 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 11 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 11 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 11 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 22 <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 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 10 3.36 COPY 501 12 PERLND 10 3.36 COPY 501 13 PERLND 11 1.93 COPY 501 12 PERLND 11 1.93 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 23 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 END MASS-LINK END RUN DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 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 Detention Vault.wdm MESSU 25 MitDetention Vault.MES 27 MitDetention Vault.L61 28 MitDetention Vault.L62 30 POCDetention Vault1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 PERLND 10 IMPLND 1 IMPLND 4 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 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 25 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 ********* 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 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 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 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 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 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 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 4 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 4 0 0 4 0 0 0 1 9 END PRINT-INFO DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 26 IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 4 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <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# *** Basin 1*** PERLND 16 1.4 RCHRES 1 2 PERLND 16 1.4 RCHRES 1 3 PERLND 10 0.74 RCHRES 1 2 PERLND 10 0.74 RCHRES 1 3 IMPLND 1 1.36 RCHRES 1 5 IMPLND 4 1.7 RCHRES 1 5 Basin 2*** IMPLND 1 0.09 COPY 501 15 IMPLND 1 0.09 COPY 601 15 ******Routing****** PERLND 16 1.4 COPY 1 12 PERLND 10 0.74 COPY 1 12 IMPLND 1 1.36 COPY 1 15 IMPLND 4 1.7 COPY 1 15 PERLND 16 1.4 COPY 1 13 PERLND 10 0.74 COPY 1 13 RCHRES 1 1 COPY 501 16 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 27 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 0.094031 0.000000 0.000000 0.175556 0.094031 0.016508 0.011370 0.351111 0.094031 0.033015 0.016080 0.526667 0.094031 0.049523 0.019694 0.702222 0.094031 0.066031 0.022740 0.877778 0.094031 0.082539 0.025424 1.053333 0.094031 0.099046 0.027851 1.228889 0.094031 0.115554 0.030083 1.404444 0.094031 0.132062 0.032160 1.580000 0.094031 0.148569 0.034110 1.755556 0.094031 0.165077 0.035956 1.931111 0.094031 0.181585 0.037711 2.106667 0.094031 0.198092 0.039387 2.282222 0.094031 0.214600 0.040996 2.457778 0.094031 0.231108 0.042543 2.633333 0.094031 0.247616 0.044036 2.808889 0.094031 0.264123 0.045481 2.984444 0.094031 0.280631 0.046880 3.160000 0.094031 0.297139 0.048239 3.335556 0.094031 0.313646 0.049561 3.511111 0.094031 0.330154 0.050849 3.686667 0.094031 0.346662 0.052105 3.862222 0.094031 0.363169 0.053331 4.037778 0.094031 0.379677 0.054529 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 28 4.213333 0.094031 0.396185 0.055702 4.388889 0.094031 0.412693 0.056851 4.564444 0.094031 0.429200 0.057977 4.740000 0.094031 0.445708 0.059081 4.915556 0.094031 0.462216 0.060165 5.091111 0.094031 0.478723 0.061230 5.266667 0.094031 0.495231 0.062277 5.442222 0.094031 0.511739 0.063306 5.617778 0.094031 0.528247 0.064319 5.793333 0.094031 0.544754 0.065317 5.968889 0.094031 0.561262 0.066299 6.144444 0.094031 0.577770 0.067267 6.320000 0.094031 0.594277 0.068221 6.495556 0.094031 0.610785 0.069162 6.671111 0.094031 0.627293 0.070090 6.846667 0.094031 0.643800 0.071007 7.022222 0.094031 0.660308 0.071911 7.197778 0.094031 0.676816 0.072804 7.373333 0.094031 0.693324 0.073687 7.548889 0.094031 0.709831 0.074559 7.724444 0.094031 0.726339 0.075421 7.900000 0.094031 0.742847 0.076273 8.075556 0.094031 0.759354 0.077116 8.251111 0.094031 0.775862 0.077950 8.426667 0.094031 0.792370 0.078775 8.602222 0.094031 0.808877 0.094708 8.777778 0.094031 0.825385 0.105319 8.953333 0.094031 0.841893 0.113035 9.128889 0.094031 0.858401 0.119488 9.304444 0.094031 0.874908 0.125185 9.480000 0.094031 0.891416 0.130361 9.655556 0.094031 0.907924 0.135151 9.831111 0.094031 0.924431 0.139639 10.00667 0.094031 0.940939 0.143881 10.18222 0.094031 0.957447 0.147919 10.35778 0.094031 0.973954 0.151783 10.53333 0.094031 0.990462 0.155496 10.70889 0.094031 1.006970 0.159077 10.88444 0.094031 1.023478 0.162542 11.06000 0.094031 1.039985 0.165901 11.23556 0.094031 1.056493 0.169165 11.41111 0.094031 1.073001 0.172343 11.58667 0.094031 1.089508 0.175443 11.76222 0.094031 1.106016 0.178470 11.93778 0.094031 1.122524 0.181430 12.11333 0.094031 1.139032 0.204882 12.28889 0.094031 1.155539 0.219984 12.46444 0.094031 1.172047 0.231563 12.64000 0.094031 1.188555 0.241532 12.81556 0.094031 1.205062 0.250512 12.99111 0.094031 1.221570 0.258799 13.16667 0.094031 1.238078 0.266562 13.34222 0.094031 1.254585 0.273908 13.51778 0.094031 1.271093 0.280911 13.69333 0.094031 1.287601 0.287625 13.86889 0.094031 1.304109 0.294090 14.04444 0.094031 1.320616 0.300337 14.22000 0.094031 1.337124 0.306390 14.39556 0.094031 1.353632 0.312271 14.57111 0.094031 1.370139 0.317995 14.74667 0.094031 1.386647 0.323577 14.92222 0.094031 1.403155 0.329028 15.09778 0.094031 1.419662 0.334359 15.27333 0.094031 1.436170 0.339579 15.44889 0.094031 1.452678 1.253684 15.62444 0.094031 1.469186 3.130535 15.80000 0.094031 1.485693 4.993734 END FTABLE 1 END FTABLES DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 29 EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** RCHRES 1 HYDR RO 1 1 1 WDM 1000 FLOW ENGL REPL RCHRES 1 HYDR STAGE 1 1 1 WDM 1001 STAG ENGL REPL COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL END EXT TARGETS MASS-LINK <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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Detention Vault 2/1/2023 3:58:41 PM Page 32 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 WWHM2012 PROJECT REPORT Figure 4.4.2 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:13:51 AM Page 2 General Model Information Project Name:Basin 2 Site Name: Site Address: City: Report Date:12/15/2022 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:13:51 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.16 Pervious Total 0.16 Impervious Land Use acre Impervious Total 0 Basin Total 0.16 Element Flows To: Surface Interflow Groundwater DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:13:51 AM Page 4 Mitigated Land Use Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.07 Pervious Total 0.07 Impervious Land Use acre ROADS FLAT 0.04 SIDEWALKS FLAT 0.05 Impervious Total 0.09 Basin Total 0.16 Element Flows To: Surface Interflow Groundwater DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:13:51 AM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.16 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.07 Total Impervious Area:0.09 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.004704 5 year 0.007388 10 year 0.008909 25 year 0.01052 50 year 0.011518 100 year 0.012366 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.038924 5 year 0.051168 10 year 0.059746 25 year 0.071145 50 year 0.080055 100 year 0.089335 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.005 0.055 1950 0.006 0.050 1951 0.010 0.034 1952 0.003 0.025 1953 0.003 0.028 1954 0.004 0.032 1955 0.006 0.035 1956 0.005 0.035 1957 0.004 0.042 1958 0.005 0.031 100-year peak flow not increased by more than 0.15 cfs. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:14:29 AM Page 8 1959 0.004 0.029 1960 0.007 0.035 1961 0.004 0.035 1962 0.002 0.028 1963 0.003 0.034 1964 0.004 0.031 1965 0.003 0.044 1966 0.003 0.027 1967 0.006 0.050 1968 0.004 0.054 1969 0.004 0.040 1970 0.003 0.036 1971 0.003 0.043 1972 0.008 0.051 1973 0.004 0.024 1974 0.004 0.041 1975 0.005 0.043 1976 0.004 0.032 1977 0.000 0.030 1978 0.003 0.038 1979 0.002 0.050 1980 0.007 0.058 1981 0.003 0.040 1982 0.006 0.061 1983 0.005 0.044 1984 0.003 0.029 1985 0.002 0.040 1986 0.008 0.034 1987 0.007 0.050 1988 0.003 0.029 1989 0.002 0.036 1990 0.015 0.087 1991 0.009 0.065 1992 0.004 0.029 1993 0.004 0.024 1994 0.001 0.024 1995 0.005 0.035 1996 0.011 0.042 1997 0.009 0.040 1998 0.002 0.036 1999 0.009 0.082 2000 0.004 0.039 2001 0.001 0.039 2002 0.004 0.054 2003 0.005 0.042 2004 0.007 0.076 2005 0.005 0.035 2006 0.006 0.032 2007 0.011 0.078 2008 0.014 0.064 2009 0.007 0.045 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0151 0.0875 2 0.0144 0.0821 3 0.0112 0.0785 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:14:29 AM Page 9 4 0.0110 0.0757 5 0.0104 0.0653 6 0.0092 0.0641 7 0.0091 0.0605 8 0.0086 0.0578 9 0.0082 0.0546 10 0.0077 0.0540 11 0.0073 0.0537 12 0.0072 0.0506 13 0.0071 0.0502 14 0.0070 0.0502 15 0.0066 0.0501 16 0.0065 0.0498 17 0.0064 0.0445 18 0.0058 0.0440 19 0.0056 0.0437 20 0.0056 0.0434 21 0.0052 0.0426 22 0.0052 0.0423 23 0.0051 0.0420 24 0.0051 0.0420 25 0.0050 0.0410 26 0.0047 0.0401 27 0.0047 0.0399 28 0.0046 0.0399 29 0.0044 0.0397 30 0.0042 0.0390 31 0.0041 0.0386 32 0.0040 0.0377 33 0.0040 0.0363 34 0.0040 0.0363 35 0.0040 0.0356 36 0.0039 0.0353 37 0.0038 0.0351 38 0.0037 0.0349 39 0.0036 0.0349 40 0.0036 0.0348 41 0.0035 0.0346 42 0.0035 0.0343 43 0.0034 0.0340 44 0.0034 0.0339 45 0.0033 0.0318 46 0.0033 0.0317 47 0.0032 0.0317 48 0.0032 0.0313 49 0.0031 0.0310 50 0.0031 0.0301 51 0.0029 0.0292 52 0.0028 0.0291 53 0.0026 0.0290 54 0.0025 0.0290 55 0.0021 0.0278 56 0.0020 0.0275 57 0.0019 0.0268 58 0.0018 0.0255 59 0.0012 0.0242 60 0.0007 0.0239 61 0.0004 0.0238 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:14:56 AM Page 15 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:14:56 AM Page 16 Appendix Predeveloped Schematic DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:14:59 AM Page 17 Mitigated Schematic DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 18 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 Basin 2.wdm MESSU 25 PreBasin 2.MES 27 PreBasin 2.L61 28 PreBasin 2.L62 30 POCBasin 21.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 2 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 19 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 20 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 2*** PERLND 10 0.16 COPY 501 12 PERLND 10 0.16 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 21 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 22 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 Basin 2.wdm MESSU 25 MitBasin 2.MES 27 MitBasin 2.L61 28 MitBasin 2.L62 30 POCBasin 21.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 8 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 *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 23 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 8 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 24 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 0.07 COPY 501 12 PERLND 16 0.07 COPY 501 13 IMPLND 1 0.04 COPY 501 15 IMPLND 8 0.05 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 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 25 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Basin 2 12/15/2022 10:15:02 AM Page 28 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. 2005-2022; 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 4.5 Water Quality System Developed Basin 1 This project is required to provide Basic Water Quality treatment according to the 2022 CORSWDM. This requirement will be met by providing a Stormfilter System directly downstream of the onsite detention vault. The Stormfilter System will be designed to treat the 2-year release rate from the detention facility as outlined in the 2022 CORSWDM. Developed Basin 2 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. This basin contains less than 5,000 square feet of new plus replaced pollution generating surface areas, therefore a water quality facility will not be required for this basin. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 5.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN The onsite and frontage conveyance system will consist of curb, gutter, catch basins and storm drainage pipe. Conveyance calculations for the pipes will be completed using the rational method and will be provided during final engineering. These conveyance systems will be designed in accordance with the 2022 CORSWDM. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 6.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 6.0 SPECIAL REPORTS AND STUDIES 6.1 Geotechnical Engineering Study prepared by Earth Solutions NW, LLC. dated November 21, 2022 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 EarthSolutionsNWLLC EarthSolutions NW LLC 15365 N.E.90th Street,Suite 100 Redmond,WA 98052 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com Geotechnical Engineering Construction Observation/Testing Environmental Services GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL PLAT 15509 –116 AVENUE SOUTHEAST RENTON,WASHINGTON ES-8888 TH DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 PREPARED FOR ICHIJO USA CO., LTD. November 21, 2022 _________________________ Chase G. Halsen, L.G. Senior Project Geologist _________________________ Keven D. Hoffmann, P.E. Associate Principal Engineer GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL PLAT 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 11/21/2022 11/21/2022 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 Report Geotechnical-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 Times Geotechnical 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 Guidance Some 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 November 21, 2022 ES-8888 Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Mr. Kanon Kupferer Greetings, Mr. Kupferer: 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. Senior Project Geologist 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 .............................................. 3 Erosion Hazard ............................................................. 4 Coal Mine Hazard ......................................................... 4 DISCUSSION AND RECOMMENDATIONS ....................................... 4 General .................................................................................... 4 Site Preparation and Earthwork ............................................. 4 Temporary Erosion Control ......................................... 5 Stripping ....................................................................... 5 Excavations and Slopes .............................................. 5 In-situ and Imported Soil ............................................. 6 Subgrade Preparation .................................................. 6 Structural Fill ................................................................ 6 Foundations ............................................................................ 7 Seismic Design ....................................................................... 8 Slab-on-Grade Floors ............................................................. 9 Retaining Walls ....................................................................... 9 Drainage................................................................................... 10 Infiltration Feasibility ................................................... 10 Preliminary Detention Vault Design ............................ 10 Preliminary Pavement Sections ............................................. 11 Utility Support and Trench Backfill ....................................... 12 LIMITATIONS ...................................................................................... 13 Additional Services ................................................................. 13 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL PLAT 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:  Online Web Soil Survey (WSS) resource, maintained by the Natural Resources Conservation Service under the United States Department of Agriculture (USDA).  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).  Preliminary Plat Map, prepared by Barghausen Consulting Engineers, Inc., dated July 13, 2022. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 2 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. 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 test pit locations were analyzed following both Unified Soil Classification System (USCS) and USDA methods and procedures. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 3 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. 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. Geologically Hazardous Areas Renton Municipal Code (RMC) 4-3-050 classifies geologically hazardous areas as those areas susceptible to damage relating to steep 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. Furthermore, based on our review of the RMC, the site is considered to possess low erosion hazard potential. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 4 Earth Solutions NW, LLC 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. 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, and stormwater management design. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 5 Earth Solutions NW, LLC 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. 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) DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 6 Earth Solutions NW, LLC 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). 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 7 Earth Solutions NW, LLC 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 350 pcf (equivalent fluid)  Coefficient of friction 0.40 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 8 Earth Solutions NW, LLC 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. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 9 Earth Solutions NW, LLC 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 350 pcf (equivalent fluid)  Coefficient of friction 0.40  Seismic surcharge 8H psf† * Where applicable. † Where H equals the retained height (in feet). 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 10 Earth Solutions NW, LLC 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. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 11 Earth Solutions NW, LLC 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. 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 12 Earth Solutions NW, LLC 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. 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 on-site 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Ichijo USA Co., Ltd. ES-8888 November 21, 2022 Page 13 Earth Solutions NW, LLC 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.MRS Checked CGH Date Nov.2022 Date 11/21/2022 Proj.No.8888 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Vicinity Map United Christian Church Property 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 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Plate Proj.No. Date Checked By Drwn.ByEarthSolutionsNWLLCGeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCMRS 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 Existing Buildings (to remain) Proposed Lot Number 0 1 0 0 2 0 0 Scale in Feet1"=2 0 0 ' CGH 11/21/2022 8888 2TestPitLocationPlan UnitedChristianChurchPropertyRenton,WashingtonTP-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 E D MO N DS WA Y S.E. Tract C Tract B Tract A S.E. 19 T H S T R E E T DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.MRS Checked CGH Date Nov.2022 Date 11/21/2022 Proj.No.8888 Plate 3 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC 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 DRAW ING Retaining Wall Drainage Detail United Christian Church Property Renton,Washington DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drwn.MRS Checked CGH Date Nov.2022 Date 11/21/2022 Proj.No.8888 Plate 4 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC 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 DRAW ING Footing Drain Detail United Christian Church Property Renton,Washington DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 >12%Fines<5%FinesHighlyOrganicSoilsSiltsandClaysLiquidLimit50orMoreSiltsandClaysLiquidLimitLessThan50Fine-GrainedSoils-50%orMorePassesNo.200SieveCoarse-GrainedSoils-MoreThan50%RetainedonNo.200SieveSands-50%orMoreofCoarseFractionPassesNo.4SieveGravels-MoreThan50%ofCoarseFractionRetainedonNo.4Sieve>12%Fines<5%FinesGW 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 without sand or gravel;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 NNWW LLC Geotechnical Engineering,Construction Observation/Testing and Environmental Services EXPLORATION LOG KEYFillFILLMadeGround Classifications of soils in this geotechnical report and as shown on the exploration logs are based on visual field and/or laboratory observations,which include density/consistency,moisture condition,grain size,and plasticity estimates,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 grout surface seal 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 EarthSolutions NW LLC Cobbles Gravel Coarse Gravel Fine Gravel 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) DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 5.3 MC = 3.0 MC = 5.5 Fines = 8.7 MC = 10.9 MC = 8.8 Fines = 7.6 OC = 0.8 CEC = 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 -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 of subsurface conditions. 0.5 6.5 13.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-1 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 -becomes gray, dense -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 a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 7.5 11.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-2 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 4.4 Fines = 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] -becomes dense -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 10.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-3 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 -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 10.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-4 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 4.4 MC = 9.9 MC = 6.8 Fines = 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 Brown sandy SILT, dense, damp -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 10.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-5 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 -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 of subsurface conditions. 1.0 13.0 14.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-6 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 3.7 MC = 4.7 OC = 0.7 CEC = 3.0 MC = 6.1 MC = 4.5 Fines = 13.8 TPSL GM SM Dark brown TOPSOIL, root intrusions to 3' Brown silty GRAVEL with sand, medium dense, damp -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 a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 0.5 6.5 12.0SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-7 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 2.9 MC = 4.5 MC = 4.1 Fines = 15.2 MC = 7.2 OC = 0.7 CEC = 3.4 TPSL GM SM Dark brown TOPSOIL, root intrusions to 2' Brown silty GRAVEL with sand, medium dense, damp -becomes gray, dense 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 a standalone document. Refer to the text of the geotechnical report for a complete understanding of subsurface conditions. 1.0 7.5 10.5SAMPLE TYPENUMBERDEPTH(ft)0 5 10 PAGE 1 OF 1 TEST PIT NUMBER TP-8 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 of subsurface conditions. 0.5 8.0SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-9 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 MC = 8.6 MC = 9.4 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 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 of subsurface conditions. 0.5 9.0SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-10 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 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 of subsurface conditions. 0.5 4.0 9.0SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-11 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 -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 of subsurface conditions. 0.5 9.0SAMPLE TYPENUMBERDEPTH(ft)0 5 PAGE 1 OF 1 TEST PIT NUMBER TP-12 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 PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property GENERAL BH / TP / WELL - 8888.GPJ - GINT US.GDT - 11/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOGDocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-8888 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 PERCENT FINER BY WEIGHTD10 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 GRAIN SIZE USDA ES-8888 UNITED CHRISTIAN CHURCH PROPERTY.GPJ GINT US LAB.GDT 10/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 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 PERCENT FINER BY WEIGHTD10 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 GRAIN SIZE USDA ES-8888 UNITED CHRISTIAN CHURCH PROPERTY.GPJ GINT US LAB.GDT 10/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 TP-01, 13.0'10/21/22 8.8 99.2 0.8 TP-07, 7.0'10/21/22 4.7 99.3 0.7 TP-08, 10.5'10/21/22 7.2 99.3 0.7 SUMMARY OF LABORATORY RESULTS PAGE 1 OF 1 Sample Location Date Test Completed Water Content (%) Ash Content (%) Organic Content (%) Borehole, Depth PROJECT NUMBER ES-8888 PROJECT NAME United Christian Church Property ESNW ORGANIC CONTENT REPORT ES-8888 UNITED CHRISTIAN CHURCH PROPERTY.GPJ ESNW_DATATEMPLATE.GDT 10/21/22Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Am Test Inc. 13600 NE 126TH PL Suite C Kirkland, WA 98034 (425) 885-1664 www.amtestlab.com Professional Analytical Services ANALYSIS REPORT EARTH SOLUTIONS NW Date Received: 10/18/22 1805 136TH PL NE Date Reported: 11/ 2/22 BELLEVUE, WA 98005 Attention: KEVEN HOFFMANN Project Name: UNITED CHRISTIAN CHURCH PROPERTY Project #: ES-8888 All results reported on an as received basis. _________________________________________________________________________________________________ AMTEST Identification Number 22-A018146 Client Identification TP-01, 13' Sampling Date 10/18/22 Conventionals PARAMETER RESULT UNITS Q D.L. METHOD ANALYST DATE Cation Exchange Capacity 4.8 meq/100g 0.5 SW-846 9081 CM 11/02/22 _________________________________________________________________________________________________ AMTEST Identification Number 22-A018147 Client Identification TP-07, 7' Sampling Date 10/18/22 Conventionals PARAMETER RESULT UNITS Q D.L. METHOD ANALYST DATE Cation Exchange Capacity 3.0 meq/100g 0.5 SW-846 9081 CM 11/02/22 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 EARTH SOLUTIONS NW Project Name: UNITED CHRISTIAN CHURCH PROPERTY AmTest ID: 22-A018148 _________________________________________________________________________________________________ AMTEST Identification Number 22-A018148 Client Identification TP-08,10.5' Sampling Date 10/18/22 Conventionals PARAMETER RESULT UNITS Q D.L. METHOD ANALYST DATE Cation Exchange Capacity 3.4 meq/100g 0.5 SW-846 9081 CM 11/02/22 _________________________________ Kathy Fugiel President DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Earth Solutions NW, LLC Report Distribution ES-8888 EMAIL ONLY Ichijo USA Co., Ltd. 1406 – 140th Place Northeast, Suite 104 Bellevue, Washington 98007 Attention: Mr. Kanon Kupferer EMAIL ONLY Barghausen Consulting Engineers, Inc. 18215 – 72nd Avenue South Kent, Washington 98032 Attention: Mr. Barry Talkington, P.E. Ms. Ivana Halvorsen Mr. Vicente Varas, P.E. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 7.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 7.0 OTHER PERMITS All permits required will be provided during final engineering. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 8.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 8.0 ESC ANALYSIS AND DESIGN An erosion and sediment control plan will be provided during final engineering. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 9.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 9.0 BOND QUANTITIES AND FACILITY SUMMARIES This section will be completed during final engineering. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 Tab 10.0 DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755 22298.001-DRNG 10.0 OPERATIONS AND MAINTENANCE MANUAL An Operations and Maintenance Manual will be provided during final engineering. DocuSign Envelope ID: 88ED493A-1813-4C83-AC0E-63CD05982755