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2023 D. R. STRONG Consulting Engineers Inc. Mountain View Gardens Technical Information Report Renton, Washington TECHNICAL INFORMATION REPORT for MOUNTAIN VIEW GARDENS 2103 Talbot Road S, Renton, Washington 98055 ____________________________________________________________________________ DRS Project No. 22052 Renton File No. PRE22-00358 Owner/Applicant Lili Lu Seattle LLL LLC 325 118th Ave SE, Suite 100 Bellevue, Washington 98005 (206) 228-4158 Report Prepared by D. R. STRONG Consulting Engineers, Inc. 620 7th Avenue Kirkland, WA 98033 (425) 827-3063 Report Issue Date July 26, 2023 2023 D. R. STRONG Consulting Engineers Inc. Mountain View Gardens Technical Information Report Renton, Washington TECHNICAL INFORMATION REPORT MOUNTAIN VIEW GARDENS TABLE OF CONTENTS SECTION I ...................................................................................................................... 4 Project Overview ......................................................................................................... 4 Predeveloped Site Conditions ..................................................................................... 4 Developed Site Conditions .......................................................................................... 4 King County Area, Washington .................................................................................. 14 SECTION II ................................................................................................................... 16 Conditions and Requirements Summary ................................................................... 16 Conditions of Approval............................................................................................... 18 SECTION III .................................................................................................................. 19 Off-Site Analysis ........................................................................................................ 19 Task 1: Define and Map Study Area ...................................................................... 19 Task 2: Resource Review ...................................................................................... 20 Task 3: Field Inspection ......................................................................................... 29 Task 4: Drainage System Description and Problem Descriptions .......................... 30 Task 5: Mitigation of Existing or Potential Problems .............................................. 31 SECTION IV .................................................................................................................. 35 Flow Control Analysis and Water Quality Design ...................................................... 35 Existing Site Hydrology .......................................................................................... 35 Developed Site Hydrology ...................................................................................... 37 Performance Standards ............................................................................................. 39 Water Quality Treatment System ............................................................................... 40 SECTION V ................................................................................................................... 42 Conveyance System Analysis and Design ................................................................ 42 SECTION VI .................................................................................................................. 43 Special Reports and Studies ..................................................................................... 43 SECTION VII ................................................................................................................. 44 Other Permits, Variances and Adjustments ............................................................... 44 SECTION VIII ................................................................................................................ 45 CSWPPP Analysis and Design (Part A) .................................................................... 45 SWPPP Plan Design (Part B) .................................................................................... 45 SECTION IX .................................................................................................................. 47 Bond Quantities, Facility Summaries, and Declaration of Covenant .......................... 47 Stormwater Facility Summary Sheet.......................................................................... 48 2023 D. R. STRONG Consulting Engineers Inc. Mountain View Gardens Technical Information Report Renton, Washington SECTION X ................................................................................................................... 50 Operations and Maintenance Manual ........................................................................ 50 APPENDICES ............................................................................................................... 51 Appendix “A” Legal Description ................................................................................. 52 Appendix “B” WWHM Report ..................................................................................... 53 Appendix “C” CSWPPP ............................................................................................. 54 Appendix “D” Bond Quantity Worksheet .................................................................... 55 List of Figures Figure 1 TIR Worksheet .................................................................................................. 6 Figure 2 Vicinity Map ..................................................................................................... 11 Figure 3 Drainage Basins, Subbasins, and Site Characteristics ................................... 12 Figure 4 Soils ................................................................................................................ 13 Figure 5 City of Renton Topography Map ..................................................................... 21 Figure 6 City of Renton Coal Mine Hazard Areas Map.................................................. 22 Figure 7 City of Renton Flood Hazards Map ................................................................. 23 Figure 8 City of Renton Streams and Wetlands Map .................................................... 24 Figure 9 City of Renton Landslide Hazards Map ........................................................... 25 Figure 10 City of Renton Seismic Hazard Areas Map ................................................... 26 Figure 11 FEMA Map .................................................................................................... 27 Figure 12 King County iMap Drainage Complaints Map................................................ 28 Figure 13 Offsite Analysis Downstream Map ................................................................ 32 Figure 14 Offsite Analysis Downstream Table .............................................................. 33 Figure 15 Predeveloped Area Map................................................................................ 36 Figure 16 Developed Area Map .................................................................................... 38 Figure 17 Detention & Water Quality Facility Details ..................................................... 41 2023 D. R. STRONG Consulting Engineers Inc. Page 4 Mountain View Gardens Technical Information Report Renton, Washington SECTION I PROJECT OVERVIEW The Project is the proposed subdivision of one parcel into six single-family residential lots, per the City of Renton’s (City) short plat process. The Project is located at 2103 Talbot Road S, Renton, Washington (Site) also known as Tax Parcel Numbers 722200- 0175. The Project will meet the drainage requirements of the 2022 City of Renton Surface Water Design Manual (Manual). PREDEVELOPED SITE CONDITIONS The total existing Site area is approximately 60,618 s.f. (1.392 acres). The Site is currently developed with one single family home, a deck, one detached building, one detached garage, a shed, a concrete driveway, a walkway, and a gravel driveway. The western portion of the Site appears to be have previously been used as a pasture area. The Site consists of a moderate grade, approximately 8%, to the northwest. The Site is contained within one Threshold Discharge Area (TDA 1) and contains one Natural Discharge Area (NDA 1) and one Natural Discharge Location (NDL 1). Runoff generated by TDA 1 gradually sheet flows west to northwest across the western property line (NDL 1) and is collected by a storm conveyance system, flowing north, along Shattuck Ave S. Drainage from an adjacent property to the south east discharges onto the site via a culvert outlet. A ditch is present along the southern property line which conveys this runoff to the existing storm system. For the purpose of hydrologic calculations, the developable area is modeled as till forest, and flow through areas will be modeled in their existing conditions. DEVELOPED SITE CONDITIONS The applicant is seeking approval to subdivide 1.392 acres into six single–family residential lots (Project), with lot sizes ranging from approximately 5,500 s.f. to 8,948 s.f. All existing improvements located on the Site will be demolished, with the exception of the existing house, during plat construction. The project is required to meet the City’s Flow Control Duration Standard – Matching Forested and Basic Water Quality treatment. This standard matches the developed Site flow durations to the flow durations of pre-developed rates for forested (historical) site conditions. These standards will be met through the proposed combination detention and water quality vault. The vault will discharge to the existing storm drainge system in Shattuck Ave S at the NDL for the Site. The proposed impervious surface areas are as follows: fronage improvements along Shattuck Ave S and Talbot Road S. The new access road, the 5 new single-family residences , one existing residence, associated driveways, and Tract A, the storm water detention facility. Total target surfaces will generate approximately 41,4582 s.f. of impervious area (0.955 acres). The Project will implement the restricted footprint BMP and the allowable impervious of each lot will be reduced by 10%. A section of non-target surface along the Talbot Road S ROW will also be collected by the proposed detention facility. The facility has been designed with this section being 2023 D. R. STRONG Consulting Engineers Inc. Page 5 Mountain View Gardens Technical Information Report Renton, Washington proposed as an offsite flow-through area. This area will be modeled in its existing conditions in both the predeveloped and developed scenarios. Proposed Site cover and surfaces are show in Figure 16, Developed Site Conditions. (See Section IV). 2023 D. R. STRONG Consulting Engineers Inc. Page 6 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 1 TIR WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner: Lili Lu Phone: (206) 228-4158 Address: 325 118th Ave SE, Suite 100, Bellevue, WA 98005 Project Engineer: Jonathan S. Murray, P.E. Company: D. R. STRONG Consulting Engineers Phone: (425) 827-3063 Project Name: Mountain View Gardens City Permit#: Location: Township: 23 North Range: 05 East Section: 19 Site Address: 2103 Talbot Road S, Renton, WA 98055 Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse Services Subdivision / Short Subdivision / UPD Building Services: M/F / Commercial / SFR Clearing and Grading Right-of-Way Other: DFW HPA Shoreline Mngmt COE 404 Structural DOE Dam Safety Rockery/Vault FEMA Floodplain ESA Section 7 COE Wetlands Other: Part 5 PLAN AND REPORT INFORMATION Technical Information Report Type of Drainage Review Full / Targeted / (circle): Large Site Date (include revision dates): Date of Final: Site Improvement Plan (Engr. Plans) Type (circle one): Full / Modified / : Small Site Date (include revision dates): Date of Final: Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) _____________________________________________________________________________________ _____________________________________________________________________________________ ____________________________________________________________________________________ Date of Approval: 2023 D. R. STRONG Consulting Engineers Inc. Page 7 Mountain View Gardens Technical Information Report Renton, Washington Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: TBD Completion Date Describe: Monitor discharge location during construction. Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Planning Area: Newcastle Special District Overlays: N/A Drainage Basin: Black River Drainage Basin, Duwamish – Green River Watershed Stormwater Requirements: Flow Control Duration Standard – Matching Forested and Basic WQ treatment Part 9 ONSITE AND ADJACENT SENSITIVE AREAS River/ Stream: Lake Wetlands Closed Depression Floodplain Other Steep Slope Erosion Hazard Landslide Hazard: Moderate to high Coal Mine Hazard: Moderate Seismic Hazard Habitat Protection Part 10 SOILS Soil Type BeC Slopes 6-15% Erosion Potential Moderate to Severe High Groundwater Table Sole Source Aquifer other Seeps/Springs Additional Sheets Attached 2023 D. R. STRONG Consulting Engineers Inc. Page 8 Mountain View Gardens Technical Information Report Renton, Washington Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core Requirement #2 – Offsite Analysis SEPA Additional Sheet Attached LIMITATION / SITE CONSTRAINT Part 12 TIR SUMMARY SHEET Threshold Discharge Area: Site comprised of one TDA (name or description) Core Requirements (all 8 apply) Discharge of Natural Location Yes Number of Natural Discharge Locations: 1 Offsite Analysis Level: 1 / 2 / 3 dated: 05/09/2023 Flow Control Level: 1 / 2 / 3 or Exemption Number (incl. facility summary sheet Small Site BMPS Restricted Footprint Conveyance System Spill containment located at: TBD Erosion and Sediment Control ESC Site Supervisor: T/B/D Contact Phone: T/B/D After Hours Phone: T/B/D Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Provided: Yes / No Liability Water Quality Type: Basic / Sens Lake / Enhanced Basic / Bog (include facility summary sheet) or exemption No. Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Type: CDA / SDO / MDP / BP / LMP / Shared / None Requirements Name: Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): Datum: Flood Protection Facilities Describe: N/A Source Control Describe Landuse: (comm. / industrial landuse) Describe any structural controls: Oil Control High-use Site: Yes / No Treatment BMP: Maintenance Agreement: Yes / No with whom? 2023 D. R. STRONG Consulting Engineers Inc. Page 9 Mountain View Gardens Technical Information Report Renton, Washington Other Drainage Structures Describe: Runoff will be collected and conveyed to the detention facility’s proposed location in Tract A. 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 MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surfaces Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris, Ensure Operations of Permanent Facilities Flag Limits of SAO and open space Preservation areas Other Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility Flow Control BMPs Other Wet-Vault Restricted Footprint Biofiltration Wetpool Media Filtration Oil Control Spill Control Flow Control BMPs Other Wet-Vault________ 2023 D. R. STRONG Consulting Engineers Inc. Page 10 Mountain View Gardens Technical Information Report Renton, Washington 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 2023 D. R. STRONG Consulting Engineers Inc. Page 11 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 2 VICINITY MAP The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map is prohibited except by written permission of King County. Site 2023 D. R. STRONG Consulting Engineers Inc. Page 12 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 3 DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS 0 GRAPHIC SCALE 755025 1 INCH = 50 FT. 2023 D. R. STRONG Consulting Engineers Inc. Page 13 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 4 SOILS 2023 D. R. STRONG Consulting Engineers Inc. Page 14 Mountain View Gardens Technical Information Report Renton, Washington KING COUNTY AREA, WASHINGTON BeC—Beausite gravelly sandy loam, 6 to 15 percent slopes a) Map Unit Setting • National map unit symbol: 1hmss • Elevation: 0 to 1,500 feet • Mean annual precipitation: 30 to 50 inches • Mean annual air temperature: 48 to 52 degrees F • Frost-free period: 160 to 220 days • Farmland classification: Not prime farmland b) Map Unit Composition • Beausite and similar soils: 95 percent • Minor components: 5 percent • Estimates are based on observations, descriptions, and transects of the mapunit. c) Description of Beausite (1) Setting • Parent material: Till over residuum from sandstone (2) Typical profile • H1 - 0 to 6 inches: gravelly ashy sandy loam • H2 – 6 to 19 inches: gravelly ashy sandy loam • H3 – 19 to 38 inches: very gravelly sandy loam • H4 – 38 to 42 inches: bedrock (3) Properties and qualities • Slope: 6 to 15 percent • Depth to restrictive feature: 24 to 40 inches to lithic bedrock • Drainage class: Well drained • Capacity of the most limiting layer to transmit water (Ksat): Moderately high to high (0.57 to 1.98 in/hr) • Depth to water table: More than 80 inches • Frequency of flooding: None • Frequency of ponding: None • Available water supply, 0 to 60 inches: Low (about 3.5 inches) (4) Interpretive groups • Land capability classification (irrigated): None specified • Land capability classification (nonirrigated): 4s • Hydrologic Soil Group: C • Ecological site: F002XA004WA – Puget Lowlands Forest • Forage suitability group: Droughty Soils (G002XF403WA) • Other vegetative classification: Droughty Soils (G002XF403WA) • Hydric soil rating: No d) Minor Components (1) Norma • Percent of map unit: 3 percent • Landform: Depressions • Other vegetative classifications: Wet Soils (G002XN102WA) • Hydric soil rating: Yes 2023 D. R. STRONG Consulting Engineers Inc. Page 15 Mountain View Gardens Technical Information Report Renton, Washington (2) Seattle • Percent of map unit: 2 percent • Landform: Depressions • Other vegetative classifications: Wet Soils (G002XN102WA) • Hydric soil rating: Yes 2023 D. R. STRONG Consulting Engineers Inc. Page 16 Mountain View Gardens Technical Information Report Renton, Washington SECTION II CONDITIONS AND REQUIREMENTS SUMMARY The Project must comply with the following Core and Special Requirements: • C.R. #1 – Discharge at the Natural Location: Existing drainage exits the Site at one location, maintaining one TDA. The topography indicates that all stormwater runoff leaves the Site as sheet flow across the west property line. Runoff is collected by an existing storm conveyance system along Shattuck Ave S., west of the Site. Discharge from the project will be directed to the storm conveyance system along Shattuck Ave S. • C.R. #2 – Offsite Analysis: Analysis is included in Section III. The Analysis describes the Site’s runoff patterns in detail. • C.R. #3 – Flow Control: The Project is required to adhere to Flow Control Duration Standard – Matching Forested site conditions. One detention/wetvault will provide flow control as required for the new and replaced impervious and pervious surfaces. The Site is required to “match the flow duration of pre-developed rates for forested (historic) site conditions over the range of flows extending from 50% of 2-year up to the full 50-year flow,” (2022 City of Renton Surface Water Design Manual, Sec. 1.2.3.1). • C.R. #4 – Conveyance System: New pipe systems are required to be designed with sufficient capacity to convey and contain (at minimum) the 25-year peak flow, assuming developed conditions for onsite tributary areas and existing conditions for any offsite tributary areas. Pipe system structures may overtop for runoff events that exceed the 25-year design capacity, provided the overflow from a 100-year runoff event does not create or aggravate a “severe flooding problem” or “severe erosion problem” as defined in C.R. #2. Any overflow occurring onsite for runoff events up to and including the 100-year event must discharge at the natural location for the project site. In residential subdivisions, such overflow must be contained within an onsite drainage easement, tract, covenant or public right-of-way. This analysis will be shown in Section V during the final engineering phase. • C.R. #5 – Erosion and Sediment Control: The Project will provide the seven minimum ESC measures. A temporary erosion and sedimentation control plan will prepared as part of the final engineering phase. • C.R. #6 – Maintenance and Operations: Maintenance of the proposed storm drainage facilities will be the responsibility of the City. An Operation and Maintenance Manual will be included at time of final engineering. • C.R. #7 – Financial Guarantees: Prior to commencing construction, the Applicant must post a drainage facilities restoration and site stabilization financial guarantee. For any constructed or modified drainage facilities to be maintained and operated by the City, the Applicant must: 1) Post a drainage defect and maintenance financial guarantee for a period of two years, and 2) Maintain the drainage facilities during the 2023 D. R. STRONG Consulting Engineers Inc. Page 17 Mountain View Gardens Technical Information Report Renton, Washington two-year period following posting of the drainage defect and maintenance financial guarantee. • C.R. #8 – Water Quality: The Project is required to provide basic water quality treatment. A combined detention/wetvault will accommodate this requirement. • S.R. #1 – Other Adopted Area-Specific Requirements: Not applicable for this Project. • S.R. #2 – Flood Hazard Area Delineation: Not applicable for this Project. • S.R. #3 – Flood Protection Facilities: Not applicable for this Project. • S.R. #4 – Source Control: Not applicable for this Project. • S.R. #5 – Oil Control: Not applicable for this Project. • S.R. #6 – Aquifer Protection Area: Site not located within zones 1 and 2, therefore not applicable for this Project. 2023 D. R. STRONG Consulting Engineers Inc. Page 18 Mountain View Gardens Technical Information Report Renton, Washington CONDITIONS OF APPROVAL TBD 2023 D. R. STRONG Consulting Engineers Inc. Page 19 Mountain View Gardens Technical Information Report Renton, Washington SECTION III OFF-SITE ANALYSIS LEVEL ONE DOWNSTREAM ANALYSIS DISCLAIMER: This report was prepared at the request of Lili Lu for the 1.392 acre parcel known as a portion of the Southeast Quarter of Section 19, Township 23 North, Range 5 East, W.M., in King County, Tax Parcel Numbers 722200-0175 (Site). D.R. STRONG Consulting Engineers, LLC. (DRS) has prepared this report for the exclusive use of DRS, the owner, and their agents, for specific application to the development project as described herein. Use or reliance on this report, or any of its contents for any revisions of this project, or any other project, or by others not described above, is forbidden without the expressed permission by DRS. TASK 1: DEFINE AND MAP STUDY AREA This Offsite Analysis was prepared in accordance with Core Requirement #2, Section 1.2.2 of the 2022 City of Renton Surface Water Design Manual (Manual). The Site is located at 2103 Talbot Road S, Renton, Washington. The Project is the subdivision of one parcel into six single-family residential lots. See Figures 5 through 12 for maps of the study area. 2023 D. R. STRONG Consulting Engineers Inc. Page 20 Mountain View Gardens Technical Information Report Renton, Washington TASK 2: RESOURCE REVIEW • Adopted Basin Plans: The City of Renton and King County Department of Permitting and Environmental Review (DPER) and Department of Natural Resources and Parks (DNRP) do not have a specific plan for the Black River Drainage Basin. • Finalized Drainage Studies: No available applicable drainage studies at this time. • Basin Reconnaissance Summary Reports: None available. • Comprehensive Plans: Renton’s Comprehensive Plan, adopted on June 22, 2015, effective July 1, 2015. Amended December 10, 2018. • Floodplain/Floodway (FEMA) Map: No floodplains exist on site, See Figure 11. • Other Offsite Analysis Reports: None available within adjacent properties. • Sensitive Areas Map Folios, City of Renton GIS: See Figures 6-10. The City’s GIS system shows that there is no existing wetland onsite. • DNRP Drainage Complaints and Studies: Per King County Water and Land Resources Division, there is no documented complaint s within the downstream path, within approximately one mile from the Site within the last 10 years. See Figure 12. • USDA King County Soils Survey: See Figure 4 • City of Renton GIS Wetlands Map: Has identified a wetland area within one mile of the downstream path, along SR-167. See Figure 8. • Migrating River Studies: The Site is not located near the channel migration zones of Cedar River, Tolt River, Raging River, Snoqualmie River, or Green River. • King County Designated Water Quality Problems: Per the Washington State Water Quality Assessment 303(d)/305(b) Integrated Report current as of 2012, there are no water quality problems within 1 mile downstream of the Site. 2023 D. R. STRONG Consulting Engineers Inc. Page 21 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 5 CITY OF RENTON TOPOGRAPHY MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 22 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 6 CITY OF RENTON COAL MINE HAZARD AREAS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 23 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 7 CITY OF RENTON FLOOD HAZARDS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 24 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 8 CITY OF RENTON STREAMS AND WETLANDS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 25 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 9 CITY OF RENTON LANDSLIDE HAZARDS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 26 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 10 CITY OF RENTON SEISMIC HAZARD AREAS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 27 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 11 FEMA MAP Site (approx. location) 2023 D. R. STRONG Consulting Engineers Inc. Page 28 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 12 KING COUNTY IMAP DRAINAGE COMPLAINTS MAP Site 2023 D. R. STRONG Consulting Engineers Inc. Page 29 Mountain View Gardens Technical Information Report Renton, Washington TASK 3: FIELD INSPECTION UPSTREAM TRIBUTARY AREA Upon evaluation of the upstream area through examining City of Renton topographic map (see Figure 5), and King County iMap and by conducting field reconnaissance on May 9th, 2023. There is approximately 2,185 s.f. (0.050 acres) of upstream tributary area to the project area coming from Talbot Rd S to the east and 11,789 s.f. (0.271 acres) from the adjacent parcels to the south. There is an existing ditch located along the southern property line on the southwestern portion of the Site. One of the adjacent parcels to the south has a culvert outlet into the ditch. A part of the upstream runoff pipe flows and some sheet flows to the existing ditch. Most of the upstream runoff from the adjacent parcels to the south conveys west along the existing ditch and outlets to a catch basin along Shattuck Ave S., away from the Site. Minimal upstream runoff from the south is expected to sheet flow onsite. The upstream runoff from the lot frontage along Talbot Rd S sheet flows onsite. GENERAL ONSITE AND OFFSITE DRAINAGE DESCRIPTIONS The Site is contained within one Threshold Discharge Area (TDA). Runoff from the Site sheet flows over the west property line and is collected by an existing storm conveyance system along Shattuck Ave S, which is flowing in a northerly direction. The Site is under the Black River drainage basin. 2023 D. R. STRONG Consulting Engineers Inc. Page 30 Mountain View Gardens Technical Information Report Renton, Washington TASK 4: DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS DRAINAGE SYSTEM DESCRIPTION The downstream analysis is further illustrated and detailed in the Downstream Map Figure 13 and Downstream Table Figure 14. The drainage area is located within the Black River Basin. The drainage area was evaluated by reviewing available resources described in Task 2, and by conducting a field reconnaissance on May 9th, 2023 under sunny conditions. DOWNSTREAM PATH 1 The Natural Discharge Location (NDL 1) for the Site is located along the western property line. (±0’). From Point “NDL 1” to Point “A1”, runoff continues to flow west as sheet flow over till grass. No concentrated flow was observed (±0’-6’). Point “A1”, Type 1 CB. (±6’). From Point “A1” to Point “A2”, runoff is conveyed in a northerly direction as pipe flow via a 12” concrete pipe. No flow was observed (±6’-441’). Point “A2” is a Type 1 CB. (±441’). From Point “A2” to Point “A3”, runoff is conveyed in a westerly direction as pipe flow via 12” polyethylene pipe. No flow observed (±441’-461’). Point “A3” is a Type 2 CB manhole. (±461’). From Point “A3” to Point “A4”, runoff is conveyed in a northerly direction as pipe flow via an 18” polyethylene pipe. No flow observed (±461’-516’). Point “A4” is a Type 2 CB manhole. (±516’). From Point “A4” to Point “A5”, runoff is conveyed in a northerly direction as pipe flow via an 18” polyethylene pipe. No flow was observed (±516’-727’). Point “A5” is a Type 2 CB manhole. No flow observed. (±727’). From Point “A5” to Point “A6”, runoff is conveyed in a northerly direction as pipe flow via an 18” polyethylene pipe. No flow was observed. (±727’-776’). Point “A6” is a Type 2 CB manhole. (±776’). From Point “A6” to Point “A7”, runoff is conveyed in a westerly direction as pipe flow via 12” concrete pipe. No flow was observed (±776’-831’). Point “A7” is a Type 2 CB manhole. No flow was observed. (±831’). From Point “A7” to Point “A8”, runoff is conveyed in a westerly direction as pipe flow via a 12” concrete pipe. No flow was observed (±831’-1,077’). Point “A8” is a Type 1 CB. (±1,077’). From Point “A8” to Point “A9”, runoff is conveyed in a westerly direction as pipe flow via 8” concrete pipe. No flow was observed (±1,077’-1,187’). Point “A9” is a Type 1 CB. (±1,187’). 2023 D. R. STRONG Consulting Engineers Inc. Page 31 Mountain View Gardens Technical Information Report Renton, Washington From Point “A9” to Point “A10”, runoff is conveyed in a westerly direction as pipe flow via a 12” concrete pipe. No flow was observed (±1,187’-1,306’). Point “A10” is a Type 1 CB. (±1,306’). From Point “A10” to Point “A11”, runoff is conveyed in a northwesterly direction as pipe flow via an 18” CMP. No flow was observed (±1,306’-1,405’). Point “A11”, is the discharge point for the Site’s downstream conveyance system. (1,405’). The runoff continues west, reaching its outfall on a wetland along SR-167. (±1,985’) TASK 5: MITIGATION OF EXISTING OR POTENTIAL PROBLEMS A review of the King County Water and Land Resources Division – Drainage Services Section Documented Drainage Complaints within one mile of the downstream flow paths revealed no complaint within the last ten years. The Project should not create any problems as specified in Section 1.2.2.1 of the Manual and therefore is not required to provide Drainage Problem Impact Mitigation subject to the requirements of Section 1.2.2.2. A combination detention/wetvault will provide flow control and basic water quality requirements for the entire Site. During construction, standard sediment and erosion control methods will be utilized. This will include the use of a stabilized construction entrance, perimeter silt fencing, and other necessary measures to minimize soil erosion during construction. 2023 D. R. STRONG Consulting Engineers Inc. Page 32 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 13 OFFSITE ANALYSIS DOWNSTREAM MAP 0GRAPHIC SCALE3002001001 INCH = 200 FT. 2023 D. R. STRONG Consulting Engineers Inc. Page 33 Mountain View Gardens Level One Downstream Analysis Renton, Washington FIGURE 14 OFFSITE ANALYSIS DOWNSTREAM TABLE DOWNSTREAM PATH Symbol Drainage Component Type, Name, and Size Drainage Component Description Slope Distance From site Discharge Existing Problems Potential Problems Observations of field inspector resource reviewer, or resident See map Type: sheet flow, swale, Stream, channel, pipe, Pond; Size: diameter Surface area drainage basin, vegetation, cover, depth, type of sensitive area, volume % 1/4 mile = 1,320 feet Constrictions, under capacity, ponding, overtopping, flooding, habitat or organism destruction, scouring, bank sloughing, sedimentation, incision, other erosion Tributary area, likelihood of problem, overflow pathways, potential impacts. NDL 1 Natural discharge location Runoff exits at the NDL along the western property line of the Site. –0’ None Observed None Anticipated No concentrated flow observed NDL 1-A1 Sheet flow Sheet flow over till grass ±6’ None Observed None Anticipated No concentrated flow observed A1-A2 Northerly pipe flow 12” concrete pipe ±6’-441’ None Observed None Anticipated No flow observed A2 Type 1 CB ±441’ None Observed None Anticipated No flow observed A2-A3 Westerly pipe flow 12” polyethylene pipe ±441’-461 None observed None anticipated No flow observed A3 Manhole Type 2 CB ±461’ None Observed None Anticipated No flow observed A3-A4 Northerly pipe flow 18” polyethylene pipe ±461’-516’ None Observed None Anticipated No flow observed A4 Manhole Type 2 CB ±516’ None Observed None Anticipated No flow observed A4-A5 Northerly pipe flow 18” polyethylene pipe ±516’-727 None Observed None Anticipated No flow observed A5 Manhole Type 2 CB ±727’ None Observed None Anticipated No flow observed A5-A6 Northerly pipe flow 18” polyethylene pipe ±727’-776’ None Observed None Anticipated No flow observed A6 Manhole Type 2 CB ±776’ None Observed None Anticipated No flow observed 2023 D. R. STRONG Consulting Engineers Inc. Page 34 Mountain View Gardens Level One Downstream Analysis Renton, Washington A6-A7 Westerly pipe flow 12” concrete pipe ±776’-831’ None Observed None Anticipated No flow observed A7 Manhole Type 2 CB ±831’ None Observed None Anticipated No flow observed A7-A8 Westerly pipe flow 12” concrete pipe ±831’-1,077’ None Observed None Anticipated No flow observed A8 Type 1 CB ±1,077’ None Observed None Anticipated No flow observed A8-A9 Westerly pipe flow 8” concrete pipe ±1,077’- 1,187’ Partially submerged None Anticipated No flow observed A9 Type 1 CB ±1,187’ None Observed None Anticipated No flow observed A9-A10 Westerly pipe flow 12” concrete pipe ±1,187’- 1,306’ Fully submerged None Anticipated No flow observed A10 Type 1 CB ±1,306’ None Observed None Anticipated No flow observed A10-A11 Northwesterly pipe flow 18” CMP ±1,306’- 1,405’ None Observed None Anticipated No flow observed A11 Discharge point ±1,405’ None Observed None Anticipated No flow observed 2023 D. R. STRONG Consulting Engineers Inc. Page 35 Mountain View Gardens Technical Information Report Renton, Washington SECTION IV FLOW CONTROL ANALYSIS AND WATER QUALITY DESIGN Core Requirements #3, #8 and #9 require the applicant to consider flow control facilities, water quality facilities and onsite flow control BMPs, respectively. The Project does not meet the exemption criteria for CRs #3 or #8, so it will need to provide a Flow Control facility, a Water Quality facility and any feasible onsite flow control BMPs. EXISTING SITE HYDROLOGY In general, the site slopes from the southeast to the northwest, with an average slope of approximately 8%. The predeveloped Site hydrology was based off the historic Site conditions as determined by the Manual. The coverage type for the Site was assumed to be forested and will be modeled as C, Forest, Mod. The Soil Testing Report indicates that the Site is underlain by glacial till deposits which will not suitable for full infiltration. The combined project area including frontage improvements, is 68,281 s.f. (12.568 acres). An area of non-target surfaces totalling 6,523 s.f. (0.150 acres) will flow onto the Site and has been included in the pre and post-developed basins as flow through. The predeveloped basin conditions can be found on Figure 15, Predeveloped Area Map. 2023 D. R. STRONG Consulting Engineers Inc. Page 36 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 15 PREDEVELOPED AREA MAP 0 GRAPHIC SCALE 755025 1 INCH = 50 FT. 2023 D. R. STRONG Consulting Engineers Inc. Page 37 Mountain View Gardens Technical Information Report Renton, Washington DEVELOPED SITE HYDROLOGY The proposed impervious surface areas are as follows: fronage improvements along Shattuck Ave S and Talbot Road S. The new access road, the 5 new single-family residences, one existing residence, associated driveways, and Tract A, the storm water detention facility. Total target surfaces will generate approximately 41,4582 s.f. of impervious area (0.955 acres). The Project will implement the restricted footprint BMP and the allowable impervious of each lot will be reduced by 10%. A section of non-target surface along the Talbot Road S side will be collected by the proposed detention facility. The facility has been designed with this section being proposed as an offsite flow-through area. This area will be modeled in its existing conditions in both the predeveloped and developed scenarios. For the developed site conditions, the soil type remained the same meaning that all pervious surfaces were considered C soil types. Figure 16 presents the developed area breakdown. 2023 D. R. STRONG Consulting Engineers Inc. Page 38 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 16 DEVELOPED AREA MAP 0 GRAPHIC SCALE 755025 1 INCH = 50 FT. 2023 D. R. STRONG Consulting Engineers Inc. Page 39 Mountain View Gardens Technical Information Report Renton, Washington PERFORMANCE STANDARDS Conditions of the existing site. A detention wetvault will provide flow control and basic water quality treatment. The Project is required to “match the flow duration of pre- developed rates for forested (historic) site conditions over the range of flows extending from 50% of 2-year up to the full 50-year flow and matches peaks for the 2-, 10-, and 100-year return periods.” (CORSWDM, Sec. 1.2.3.1). Detention vault details will be provided at the time of final engineering. Per Section 1.2.9.1 of the CORSWDM, the project is required to supplement the flow mitigation provided by required flow control facilities by use of Best Management Practices (BMPs). Section 1.2.9.2 outlines individual lot BMP requirements and the preferred BMPs to be utilized to achieve flow mitigation. Lots that are 11,000 s.f. or less are required to mitigate 10% of the total lot size of impervious area. Small lot BMPs were determined by the BMP requirements outlined in Section 1.2.9.2.1 of the CORSWDM. As required by the CORSWDM, small lot BMP requirements were analyzed in the order of preference listed in section 1.2.9.2.1. 1. Full Dispersion: There is an insufficient amount of native growth in order to utilize full dispersion. The required undisturbed area and flowpath lengths result in full dispersion for any of the lots to be infeasible. 2. Full Infiltration: Per geotechnical infiltration evaluation, the existing soil on the Site makes full infiltration infeasible. The full geotechnical report has been submitted in conjunction with the preliminary application. 3. Limited Infiltration: Per geotechnical infiltration evaluation, the existing soil on the Site makes any form of infiltration infeasible. The full geotechnical report has been submitted in conjunction with the preliminary application. 4. Rain Gardens: Per geotechnical evaluation, the existing soil on the Site makes any form of infiltration infeasible. The full geotechnical report has been submitted in conjunction wit h the preliminary application. 5. Bioretention: Per geotechnical evaluation, the existing soil on the Site makes any form of infiltration infeasible. 6. Permeable Pavement: Per geotechnical evaluation, the existing soil on the Site makes any form of infiltration infeasible. 7. Basic Dispersion: Due to the limitations of the site sufficient flowpaths for basic dispersion cannot be provided. 8. Reduced Impervious Surface Credit: This BMP will be implemented by restricting the maximum allowable impervious surface for each lot by 10% of the lot area.. 9. Native Growth Retention Credit: This BMP is not feasible due to a lack of native growth areas. 10. Soil Amendment: “Soil Amendment” per the City of Renton’s requirements must be applied to all disturbed pervious areas on Site. 11. Perforated Pipe Connection: Any proposed connection of roof downspouts to the drainage system must be via perforated pipe connections. 2023 D. R. STRONG Consulting Engineers Inc. Page 40 Mountain View Gardens Technical Information Report Renton, Washington WATER QUALITY TREATMENT SYSTEM The Project is required to adhere to the City of Renton’s Basic Water Quality treatment criteria. A combined detention/water quality vault located within Tract A is proposed to accommodate this requirement. Sizing for a wetvault was calculated from the method provided by Section 6.4.1.1 Methods of Analysis of the Manual. The minimum wetpool volume required, as provided by the WWHM 2012 model is 0.1368 ac-ft or 5,959 cubic feet. The Project will provide 19,740 cubic feet of dead storage. The wetvault will occupy the entire footprint of the detention vault. 2023 D. R. STRONG Consulting Engineers Inc. Page 41 Mountain View Gardens Technical Information Report Renton, Washington FIGURE 17 DETENTION & WATER QUALITY FACILITY DETAILS 2023 D. R. STRONG Consulting Engineers Inc. Page 42 Mountain View Gardens Technical Information Report Renton, Washington SECTION V CONVEYANCE SYSTEM ANALYSIS AND DESIGN Per Core Requirement #4 of the KCSWDM, the conveyance system must be analyzed and designed for the existing tributary and developed onsite runoff. Pipe systems shall be designed to convey the 25-year storm with a minimum of 6-inches of freeboard between the design water surface and structure grate. Any overflow from the 100-year design storm must not create or aggravate a severe flooding problem. The Rational Method will be used to calculate the Q-Ratio for each pipe node. Conveyance analysis will be performed during final engineering. 2023 D. R. STRONG Consulting Engineers Inc. Page 43 Mountain View Gardens Technical Information Report Renton, Washington SECTION VI SPECIAL REPORTS AND STUDIES The following report and studies are included with this submittal. Geotechnical Engineering Study: Earth Solutions NW Inc. – July 18, 2023 Arborist Report: Washington Forestry Consultants, Inc – June 26, 2023 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 DEVELOPMENT TALBOT ROAD PROPERTY 2103 TALBOT ROAD SOUTH RENTON,WASHINGTON ES-9099 PREPARED FOR SEATTLE LLL, LLC July 18, 2023 _________________________ Brian C. Snow, L.G. Senior Staff Geologist _________________________ Henry T. Wright, P.E. Associate Principal Engineer _________________________ Kyle R. Campbell, P.E. Senior Principal Engineer GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT TALBOT ROAD PROPERTY 2103 TALBOT ROAD SOUTH RENTON, WASHINGTON ES-9099 Earth Solutions NW, LLC 15365 Northeast 90th Street, Suite 100 Redmond, Washington 98052 Phone: 425-449-4704 | Fax: 425-449-4711 www.earthsolutionsnw.com 07/18/2023 07/18/2023 Geotechnical-Engineering Report Important Information about This Subsurface problems are a principal cause of construction delays, cost overruns, claims, and disputes. While you cannot eliminate all such risks, you can manage them. The following information is provided to help. The Geoprofessional Business Association (GBA) has prepared this advisory to help you – assumedly a client representative – interpret and apply this geotechnical-engineering report as effectively as possible. In that way, you can benefit from a lowered exposure to problems associated with subsurface conditions at project sites and development of them that, for decades, have been a principal cause of construction delays, cost overruns, claims, and disputes. If you have questions or want more information about any of the issues discussed herein, contact your GBA-member geotechnical engineer. Active engagement in GBA exposes geotechnical engineers to a wide array of risk-confrontation techniques that can be of genuine benefit for everyone involved with a construction project. Understand the Geotechnical-Engineering Services Provided for this 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 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 July 18, 2023 ES-9099 Seattle LLL, LLC 325 – 118th Avenue Southeast, Suite 100 Bellevue, Washington 98005 Attention: Lili Lu Dear Lili: Earth Solutions NW, LLC (ESNW) is pleased to present this geotechnical report for the proposed residential development to be constructed along the west side of Talbot Road South, just west of the intersection with South 21st Street, in Renton, Washington. Based on the results of our investigation, the proposed residential construction is feasible from a geotechnical standpoint. Geologic stratigraphy observed at the subsurface exploration locations generally consisted of about 8 to 30 feet of native glacial till deposits atop competent Renton Formation sandstone and siltstone bedrock, which extended to the maximum exploration depth of about 80 feet below existing grades and to the termination depth of all exploratory borings. The subject site falls entirely within an area identified as a moderate/medium coal mine hazard area per City of Renton GIS mapping. However, based on the results of our investigation, the site can be classified as a low coal mine hazard area. In our opinion, the risk of surface subsidence due to collapsing coal mine workings may be considered very low to negligible based on the competent underlying geology and lack of coal mine related void space encountered at the exploration locations. In our opinion, coal mine hazard area regulations and specialized design considerations regarding potential surface subsidence are not necessary for this project. As such, the typical residential structure proposed to be constructed on this site can be supported on conventional spread and continuous foundations bearing on undisturbed competent native soil, recompacted native soil, or new structural fill placed directly on a competent subgrade. Competent native soil suitable for foundation support is expected to be encountered beginning at depths of about two to three feet below existing grades across the site. The native glacial till and underlying bedrock deposits exhibit very poor infiltration characteristics, including high relative density, high fines content, and weak cementation. In our opinion, full infiltration should be considered infeasible from a geotechnical standpoint. 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 Seattle LLL, LLC ES-9099 July 18, 2023 Executive Summary – Page 2 Earth Solutions NW, LLC This report provides geotechnical analyses and recommendations for the proposed residential development. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this geotechnical engineering study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Brian C. Snow, L.G. Senior Staff Geologist Earth Solutions NW, LLC Table of Contents ES-9099 PAGE INTRODUCTION ................................................................................. 1 General .................................................................................... 1 Project Description ................................................................. 2 SITE CONDITIONS ............................................................................. 3 Surface ..................................................................................... 3 Subsurface .............................................................................. 3 Topsoil and Fill ............................................................. 4 Native Soil ..................................................................... 4 Bedrock ......................................................................... 4 Geologic Setting ........................................................... 5 Groundwater ................................................................. 6 Geologic Critical Areas Review ............................................. 6 Coal Mine Hazard ......................................................... 7 Landslide Hazard.......................................................... 9 DISCUSSION AND RECOMMENDATIONS ....................................... 9 General .................................................................................... 9 Site Preparation and Earthwork ............................................. 10 Temporary Erosion Control ......................................... 10 Excavations and Slopes .............................................. 10 Structural Fill ................................................................ 11 In-situ and Imported Soil ............................................. 12 Wet Season Grading .................................................... 12 Subgrade Preparation .................................................. 13 Void Space Restoration ............................................... 13 Grading and Excavations in Bedrock ......................... 13 Foundations ............................................................................ 13 Retaining Walls ....................................................................... 14 Seismic Design ....................................................................... 15 Slab-on-Grade Floors ............................................................. 16 Utility Support and Trench Backfill ....................................... 16 Preliminary Pavement Sections ............................................. 17 Drainage................................................................................... 17 Infiltration Feasibility ................................................... 18 Preliminary Stormwater Vault Design ........................ 18 LIMITATIONS ...................................................................................... 20 Additional Services ................................................................. 20 Earth Solutions NW, LLC Table of Contents Cont’d ES-9099 GRAPHICS Plate 1 Vicinity Map Plate 2 Boring Location Plan Plate 3 Geologic Map Plate 4 Historical Coal Mine Map K32 A Plate 5 LiDAR-Based Shaded Relief Map Plate 6 Retaining Wall Drainage Detail Plate 7 Footing Drain Detail APPENDICES Appendix A Subsurface Exploration Logs Appendix B Laboratory Test Results Earth Solutions NW, LLC GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL DEVELOPMENT TALBOT ROAD PROPERTY 2103 TALBOT ROAD SOUTH RENTON, WASHINGTON ES-9099 INTRODUCTION General This geotechnical engineering study was prepared for the proposed residential development to be constructed on the west side of Talbot Road South, just west of the intersection with South 21st Street, in Renton, Washington. The purpose of this study was to provide geotechnical recommendations to support the current development plans, as understood at the time of this study. To fulfill our scope of services, the following tasks were completed: Subsurface exploration to characterize the soil and groundwater conditions and to assess potential coal mine hazards on site. Laboratory testing of representative soil samples collected at the exploration locations. Infiltration feasibility evaluation based primarily on our field observations and laboratory analyses. Engineering analyses and recommendations for the proposed residential development. Literature review of historical coal mine maps and related documentation. Preparation of this report. The following documents and resources were reviewed as part of our report preparation: Pre-Application Submittal, prepared by D.R. Strong Consulting Engineers, dated October 13, 2022. Feasibility Layout, prepared by D.R. Strong Consulting Engineers, Project No. 22058, dated July 28, 2022. Geologic Map of the Renton Quadrangle, King County, Washington, by Mullineaux, D.R., dated 1965. Web Soil Survey (WSS), online resource maintained by the Natural Resources Conservation Service (NRCS) under the United States Department of Agriculture (USDA). Seattle LLL, LLC ES-9099 July 18, 2023 Page 2 Earth Solutions NW, LLC Soil Survey of King County Area, Washington, by Snyder, D.E., Gale, P.S., and Pringle, R.F., USDA Soil Conservation Service, issued November 1973. Geology of the Renton, Auburn, and Black Diamond Quadrangles, King County, Washington: A Study of Cenozoic Bedrock and Surficial Deposits in the Southeastern Part of the Puget Sound Lowland, Geological Survey Professional Paper 672, by Mullineaux, D.R., United States Geological Survey, dated 1970. Chapter 4 (Soil and Rock Classification and Logging) of the WSDOT Geotechnical Design Manual, M 46-03.16, dated February 2022. Geologic Information Portal, online resource maintained by the Washington State Department of Natural Resources (DNR). Faults and Earthquakes in Washington State, by Czajkowski and Bowman, endorsed by the Washington State Department of Natural Resources, dated 2014. King County Landslide Hazard Areas, Map 12-1, prepared by Tetra Tech, Inc. and endorsed by the King County Flood Control District, dated May 2010. King County Liquefaction Susceptibility, Map 11-5, prepared by Tetra Tech, Inc. and endorsed by the King County Flood Control District, dated May 2010. Renton Municipal Code (RMC) Title IV, Chapter 3, Section 4-3-050. Project Description The subject site consists of a single tax parcel (King County Parcel No. 722200-0175) located on the west side of Talbot Road South, just west of the intersection with South 21st Street, in Renton, Washington. Site-specific development plans were not available for review. However, per the referenced feasibility layout, we understand the site is proposed to be developed with six residential lots, an access road, a stormwater facility, and other associated improvements. At the time of report submission, specific building load values were not available for review; however, we anticipate that typical two- to three-story residential structures will be constructed, consisting of relatively lightly loaded wood framing supported on conventional foundations. Based on our experience with similar developments, we estimate wall loads of about 2 to 3 kips per linear foot and slab-on-grade and column loading of 150 pounds per square foot (psf) will be incorporated into the final design. 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 final designs to verify the geotechnical recommendations provided in this report have been incorporated into the plans. Seattle LLL, LLC ES-9099 July 18, 2023 Page 3 Earth Solutions NW, LLC SITE CONDITIONS Surface The subject site is located on the west side of Talbot Road South, just west of the intersection with South 21st Street, in Renton, Washington. The site is comprised of a single tax parcel (King County Parcel No. 722200-0175) and totals roughly 1.39 acres in area. The approximate site location is depicted on Plate 1 (Vicinity Map). Based on the Public Land Survey System (PLSS), the site is located in the southeast quarter of the southeast quarter of section 19, township 23 north, range 5 east (SE 1/4 SE 1/4 S19, T23N, R5E). Approximated site locations shown on Plates 3 through 5 (introduced in later sections of this report) are based on measurements from PLSS section lines, which are illustrated on the attached graphics. Please note that the map on Plate 4 delineates each quarter of sections 19 (SE 1/4), 20 (SW 1/4), 29 (NW 1/4), and 30 (NE 1/4) within T23N, R5E. Plates 3 and 5 do not illustrate section quarters, but instead only depict section boundaries with respect to the PLSS. The site is currently developed with a single-family residence, outbuildings, and associated improvements. Undeveloped portions of the site are primarily surfaced with grasses and landscaping areas. Surface topography descends from east to west at gentle gradients, with an estimated 30 to 35 feet of total vertical relief across the site. The site is bordered to the north and south by existing residential development, to the east by Talbot Road South, and to the west by Shattuck Avenue South. Subsurface An ESNW representative observed, logged, and sampled five borings between May 15 and May 17, advanced at accessible locations within the property boundaries using a track-mounted mud- rotary drill rig and operators retained by ESNW. The subsurface exploration locations were selected to avoid existing improvements and utility lines and based on historical coal mine mapping (described later in this report) in areas most probable to encounter historical mine workings. The purpose of the subsurface exploration was to assess and classify the site soils, to characterize the groundwater conditions within areas proposed for new development, and to evaluate the risk of surface subsidence (and other hazards) due to suspected historical coal mine workings near the subject site. The soil borings were advanced to a maximum depth of about 80 feet bgs, and all explorations were terminated within undisturbed, competent Renton Formation bedrock. The approximate locations of the borings are depicted on Plate 2 (Boring Location Plan). Please refer to the exploration logs provided in Appendix A for a more detailed description of subsurface conditions. Representative soil samples collected at our exploration sites were analyzed in general accordance with Unified Soil Classification System (USCS) and USDA methods and procedures. Seattle LLL, LLC ES-9099 July 18, 2023 Page 4 Earth Solutions NW, LLC Topsoil and Fill Topsoil thickness was not directly observed during the subsurface exploration. Sampling methods employed during mud-rotary drilling typically bypass surficial topsoil layers, and the shallowest samples were collected at five feet bgs across the site during the exploration. In any case, based on our experience in the project vicinity, typical topsoil sections range in thickness from about 6 inches up to about 18 inches. It is possible that deeper or shallower pockets of topsoil are present in localized areas across the site. Thickness of the topsoil layer is heavily influenced historical site activities such as previous development, site grading, or agricultural practices. Topsoil can commonly be characterized by its dark brown color, the presence of fine organic material, and small root intrusions. Fill was not encountered at the exploration locations. Fill may be present in isolated areas of the site, such as the “dirt mounds” indicated on the referenced feasibility layout in the western site portion, or in areas surrounding existing site improvements and utilities. However, deep (i.e., greater than five feet thick), widespread fills were not observed during the subsurface exploration and are not expected to be present at the subject site. Native Soil In general, geologic stratigraphy can be characterized as glacial till deposits atop Renton Formation siltstone and sandstone bedrock. Thickness of the glacial till deposit varied from about 8 feet in the western portion of the site near Shattuck Avenue South, up to about 30 feet in the eastern portion near Talbot Road South. Visual and laboratory classifications of the samples collected from the glacial till deposits characterized the soils primarily as silty sand (USCS: SM) with minor amounts of scattered gravel. The native soils frequently exhibited zones of light iron oxide staining and weak cementation, which are typical of glacial till deposits. Blow counts recorded during the exploratory drilling indicate the glacial till is chiefly in a very dense condition (i.e., N>50), with isolated areas of medium dense to dense near surface deposits (i.e., at B-3, B-4, and B-5, within five feet of the existing ground surface). Based on the laboratory analyses, the silty sands contain considerable fines between about 42 and 49 percent. At boring B-2, the surficial soils were classified as a sandy silt, with fines contents of up to about 58 percent. Soil moisture was characterized as moist to wet, and moisture content typically ranged between about 10 and 20 percent. Bedrock Renton Formation bedrock was encountered at all five boring locations, and all borings were terminated within very dense, undisturbed bedrock deposits. As noted above, depth to bedrock varied from about 8 feet in the western portion of the site near Shattuck Avenue South, up to about 30 feet in the eastern portion near Talbot Road South. The observed bedrock was visually classified to include both sandstone and siltstone members of the Renton Formation. Trace to minor amounts of coal, present in millimeter-scale laminations or as sand-sized clasts, was observed throughout the explored bedrock strata and at variable depths. Seattle LLL, LLC ES-9099 July 18, 2023 Page 5 Earth Solutions NW, LLC Relevant geotechnical descriptors were taken from the referenced WSDOT Geotechnical Design Manual and incorporated into the characterization of bedrock encountered during the investigation. As such, the sandstone member was primarily characterized as light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2), with isolated areas in the upper part of the formation characterized as moderate yellowish brown (10YR 6/6) and slightly weathered (Grade II). Similarly, the deeper siltstone member was characterized primarily as very dense, moist, light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R0 to R1). N-values recorded throughout the bedrock profile observed during the exploration correlate to very dense deposits (i.e., N>50). At all boring locations, sandstone was the first rock type encountered beneath the glacial till cap. The sandstone member extended to the termination depth of borings B-3 and B-5. Underlying the sandstone and extending to the termination depth of borings B-1, B-2, and B-4, siltstone was encountered at depths of roughly 58 feet, 25 feet, and 40 feet, respectively. The sandstone member was encountered in a relatively weathered condition at borings B-1 and B-2, becoming unweathered and gray at depths between roughly 25 and 30 feet. At borings B-3 through B-5, unweathered sandstone was encountered at the upper bedrock surface and extended to the termination depth or the contact with the underlying siltstone. In general, the upper sandstone member was easily friable within the sample spoons, lacking strong cementation and a fine-grained cohesive matrix. Siltstones encountered across the site were in a relatively unweathered condition throughout the observed geologic profiles. In general, drilling through the sedimentary rocks was relatively slow, and the drill rig exhibited consistent drilling behavior indicating relatively uniform conditions and a lack of void spaces (such as an abandoned coal mine tunnel). We utilized two different drilling bits within the bedrock units: a tricone bit (standard bit for mud-rotary in the Puget Sound) was utilized to penetrate the upper glacial till and sandstone bedrock strata where the probability of encountering gravel clasts was higher (tricones are more durable through gravels). Once the boreholes were advanced through the till and upper sandstone members, the drill rig was retooled with a drag bit, providing increased drilling efficiency through the relatively dense and fine-grained lower sandstone and siltstone members. Evidence of both primary and secondary bedrock structures were observed within the collected samples. Bedding was evidenced in both silt- and sandstone members by the presence of millimeter-scale laminations, although some sections of bedrock were “massively” bedded (i.e., no bedding). Direct measurements of structural attitude and bedding orientation were not possible; however, it should be noted that the observed laminations described above were in a near-vertical orientation relative to the sampling spoon, indicating that sedimentary bedding within the Renton Formation beneath the subject site dips at high angles relative to horizontal. Geologic Setting Geologic mapping of the area indicates the site is underlain primarily by Vashon-age ground moraine (Qgt) deposits. Along the western property line and parallel with Shattuck Avenue South, Renton Formation bedrock (Tr) is identified and extends west to the Green River valley floor. The geologic map also depicts the presence of the Talbot Syncline just north of the subject site. A portion of the referenced geologic map is included on Plate 3 of this report. Seattle LLL, LLC ES-9099 July 18, 2023 Page 6 Earth Solutions NW, LLC Ground moraine deposits are synonymous with glacial till deposits and are locally divided into “lodgment till” and “ablation till.” Lodgment till generally consists of a compact and unsorted mixture of gravel, sand, silt, and clay that is commonly referred to as “hardpan.” Ablation till is similar but is typically much less compact and coherent. Renton Formation bedrock is characterized as arkosic sandstone, mudstone, and shale containing coal beds mostly near the base or middle of the formation. Renton Formation bedrock is also characterized by its numerous faults of small displacement and wavy bedding. A syncline is a fold or “trough” in which initially horizontal and planar geologic strata are deformed into concave upward geometry by compressional tectonic stresses. The fold axis, or the centerline of the fold, crosscuts immediately north of the subject property in an east-southeast, west-northwest orientation. A detailed characterization of regional geology is available in the referenced Geological Survey professional paper. The online WSS resource identifies Beausite gravelly sandy loam on 6 to 15 percent slopes (Map Unit Symbol: BeC) as the primary soil unit underlying the site. Beausite soils formed in glacial deposits underlain by sandstone at depth, and support vegetation including alder, fir, cedar, and associated brush and shrubs. Per the referenced USDA soil survey, the native soils are characterized with medium surface water runoff and moderate hazard of water erosion. In our opinion, the site geology and soil conditions are consistent with the published resources outlined in this section. Groundwater Groundwater was not observed at the boring locations primarily due to the pressurized injection of drilling fluids utilized in mud-rotary drilling techniques, which inherently obscures the observation of natural groundwater. However, based on the conditions encountered, in our opinion, significant quantities of groundwater are unlikely to be present at the subject site. If encountered, groundwater flow rates would be expected to be relatively light. It should be noted that zones of perched groundwater seepage are common within glacial deposits, particularly along sections of sloping topography, and groundwater seeps should be expected within site excavations at depth. Groundwater seepage rates and elevations may fluctuate depending on many factors, including precipitation duration and intensity, the time of year, and soil conditions. In general, groundwater flow rates are higher during the winter, spring, and early summer months. Geologic Critical Areas Review ESNW reviewed Title IV, Chapter 3, Section 4-3-050 – Critical Areas Regulations – of the Renton Municipal Code (RMC) to assess the presence of geologic critical areas at the subject site. ESNW also reviewed the City of Renton’s online GIS “COR” mapping resource, which depicts suspected critical areas throughout the jurisdiction. Regulated geologic critical areas within the City of Renton (City) include steep slopes, landslide hazards, erosion hazards, seismic hazards, and coal mine hazards. Seattle LLL, LLC ES-9099 July 18, 2023 Page 7 Earth Solutions NW, LLC Based on our review, the critical areas mapping indicates a moderate coal mine hazard area is present at the subject site. High and moderate landslide hazard areas are also indicated just off the northwest property corner, and isolated areas of “regulated slopes” are mapped around the site perimeters, most notably along the eastern property line. However, slope heights within areas identified as regulated slopes are limited to about five feet maximum per the COR map resource, and slope gradients are below the threshold to be classified as either “sensitive” or “protected” slopes. Coal Mine Hazard The subject site falls entirely within an area identified as a moderate/medium coal mine hazard area per City of Renton GIS mapping. Moderate/medium coal mine hazards are defined in the RMC as: areas where mine workings are deeper than two hundred feet (200’) for steeply dipping seams, or deeper than fifteen (15) times the thickness of the seam or workings for gently dipping seams. These areas may be affected by subsidence. Historical mine mapping available through Washington State DNR’s online Geologic Information Portal indicates the subject site is bordered on both north and south sides by abandoned underground coal mines, including the Old Patton and Sunbeam mines. We selected one map (Coal Mine Map K32 A) from the DNR catalogue to include on Plate 4 of this report. In our opinion, Map K32 A effectively and representatively illustrates the approximate site location and surrounding historical coal mining activity. Based on the historical mapping reviewed, it appears that mine entrances for the Sunbeam Mine (south of the subject site) were opened along the lower portion of the eastern Green River valley wall at elevations between roughly 50 and 65 feet. Records of the Old Patton Mine (north of the subject site) are significantly less detailed than those of the Sunbeam mine; however, it is presumed that mine entrances for the Old Patton Mine were opened in a similar fashion along the eastern Green River valley wall. Notably, the fold axis of the Talbot Syncline (also named the Patton Syncline), which crosscuts the region in an east-southeast, west-northwest orientation, separates the Sunbeam and Old Patton mines. Assuming the Talbot Syncline has relatively symmetrical fold geometry (and the axial plane is relatively vertical), historical mine workings for the Old Patton mine are likely at comparable elevations to those for the Sunbeam mine, as both mines are roughly equidistant from the fold axis. Based on topographic information available through the COR mapping resource, surface elevations at the subject site range from roughly 166 feet in the northwest site corner to about 198 feet along the eastern property line. As depicted on the historical DNR coal mine maps, mined-out areas within the Sunbeam Mine were surveyed at roughly elevation 69 feet. As such, we would expect that historical coal mine workings would be at least 97 to 129 feet bgs assuming horizontal geologic stratigraphy. However, per the geologic map, the Renton Formation stratigraphy underlying the subject site and surrounding area are deformed into concave upward geometry (a syncline). Based on our subsurface observations and structural measurements on the geologic map, strata within the Renton Formation beneath the subject site dip at steep angles towards the north. Per the historical coal mine mapping, dip angles within the mining zone of the Sunbeam Mine are documented between 55 and 65 degrees to the north. Seattle LLL, LLC ES-9099 July 18, 2023 Page 8 Earth Solutions NW, LLC As such, given the synclinal fold geometry and the relative location of the subject site roughly 200 to 500 feet north (down dip) of mapped, known mine workings, the coal seam targeted by the nearby mining operations is expected to be deepest along the fold axis. Therefore, we would expect that if mining operations had progressed directly beneath the subject site, the abandoned workings would be deeper than the estimated elevations of coal mine workings assuming horizontal stratigraphy above (i.e., 97 to 129 feet bgs), as the mining operation would have been advanced down dip and at progressively lower elevations approaching the fold axis. Readily available LiDAR mapping of the subject site reveals potential mining related disturbances west of the site – apparent fill deposits and roadcuts are present on the eastern Green River valley wall near the Sunbeam Mine entrance, and consistent with the depiction of historical mine workings shown on the historical coal mine maps. However, mining related disturbances and evidence of surface subsidence are not visible within the site boundaries on the LiDAR mapping. A LiDAR-based shaded relief map of the subject site is included on Plate 5. Geologic stratigraphy observed at the boring locations was generally characterized as about 8 to 30 feet of glacial till deposits atop competent Renton Formation sandstone and siltstone bedrock. Undisturbed Renton Formation bedrock extended to the termination depth of all five borings advanced across the property, and no evidence of open voids, loose or collapsed coal mine workings, or thick coal seams was observed within any of the boreholes. Historical mine maps do not illustrate mined-out areas directly beneath the subject site. However, based on the COR mapping of moderate/medium coal mine hazard areas encompassing the subject site, undocumented mining may have occurred. The subsurface explorations were advanced to a maximum depth of about 80 feet bgs, and as such, we are unable to conclusively rule out the presence of abandoned mine workings within the upper 200 feet of existing grades. In consideration of the evidence and reasoning outlined above, however, it is our opinion that the site can be classified as a low coal mine hazard. Low coal mine hazards are defined in the RMC as: areas with no known mine workings and no predicted subsidence. While no mines are known in these areas, undocumented mining is known to have occurred. In our opinion, the risk of surface subsidence due to collapsing coal mine workings may be considered very low to negligible based on the competent underlying geology and lack of coal mine related void space encountered at the exploration locations. In our opinion, coal mine hazard area regulations and specialized design considerations regarding potential surface subsidence are not necessary for this project. Per the RMC, any hazards found during development activities shall be immediately reported to both ESNW and the Development Services Division. Any coal mine hazards shall be mitigated prior to re-commencing construction based on supplemental recommendations or reports prepared by the geotechnical professional. Seattle LLL, LLC ES-9099 July 18, 2023 Page 9 Earth Solutions NW, LLC Landslide Hazard High and moderate landslide hazard areas are indicated on the COR map resource just off the northwest property corner. However, the referenced landslide hazard area map does not depict the same hazard area. In our opinion, based on our observations of very dense glacial till and competent Renton Formation bedrock underlying the subject site and topographic data depicted on the COR map, the mapped landslide hazard area is in error. Slope gradients surrounding the site generally fall below the 15 percent threshold to be classified as high or medium landslide hazards. Low landslide hazard areas include any areas with slopes less than 15 percent. Therefore, the site and immediately surrounding area can be classified as a low landslide hazard area. In our opinion, the risk of landsliding as a result of existing and/or proposed site development activities should be considered very low to negligible on account of the very dense and competent underlying geology. DISCUSSION AND RECOMMENDATIONS General Based on the results of our investigation, the proposed residential construction is feasible from a geotechnical standpoint. The primary geotechnical considerations associated with the proposed project include earthwork, temporary excavations, structural fill requirements, subgrade preparation, retaining wall foundation support, slab-on-grade support, utility support and trench backfill, drainage, and stormwater management. Geologic stratigraphy observed at the subsurface exploration locations generally consisted of about 8 to 30 feet of native glacial till deposits atop competent Renton Formation sandstone and siltstone bedrock, which extended to the maximum exploration depth of about 80 feet below existing grades and to the termination depth of all exploratory borings. The subject site falls entirely within an area identified as a moderate/medium coal mine hazard area per City of Renton GIS mapping. However, based on the results of our investigation, the site can be classified as a low coal mine hazard area. In our opinion, the risk of surface subsidence due to collapsing coal mine workings may be considered very low to negligible based on the competent underlying geology and lack of coal mine related void space encountered at the exploration locations. In our opinion, coal mine hazard area regulations and specialized design considerations regarding potential surface subsidence are not necessary for this project. As such, the typical residential structure proposed to be constructed on this site can be supported on conventional spread and continuous foundations bearing on undisturbed competent native soil, recompacted native soil, or new structural fill placed directly on a competent subgrade. Competent native soil suitable for foundation support is expected to be encountered beginning at depths of about two to three feet below existing grades across the site. Seattle LLL, LLC ES-9099 July 18, 2023 Page 10 Earth Solutions NW, LLC The native glacial till and underlying bedrock deposits exhibit very poor infiltration characteristics, including high relative density, high fines content, and weak cementation. In our opinion, full infiltration should be considered infeasible from a geotechnical standpoint. This study has been prepared for the exclusive use of Seattle LLL, LLC, and its representatives. A warranty is neither expressed nor implied. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Site preparation activities should consist of installing temporary erosion control measures and performing site stripping within the designated clearing limits. Subsequent earthwork activities may involve additional grading and utility installations. Temporary Erosion Control The following temporary erosion and sediment control (TESC) Best Management Practices (BMPs) should be considered: Temporary construction entrances and drive lanes, consisting of at least six inches of quarry spalls, should be considered to both minimize off-site soil tracking and provide stable surfaces at site entrances. Placing geotextile fabric underneath the quarry spalls will provide greater stability, if needed. Silt fencing should be placed around the appropriate portions of the site perimeter. When not in use, soil stockpiles should be covered or otherwise protected to reduce the potential for soil erosion, especially during periods of wet weather. Temporary measures for controlling surface water runoff, such as interceptor trenches, sumps, or interceptor swales, should be installed prior to beginning earthwork activities. Dry soils disturbed during construction should be wetted to minimize dust and airborne soil erosion. Additional TESC BMPs, as specified by the project civil engineer and indicated on the plans, should be incorporated into construction activities. TESC BMPs may be modified during construction as site conditions require and as approved by the site erosion control lead. Excavations and Slopes Based on the soil conditions observed at the exploration locations, excavation activities are likely to expose medium dense to dense native soils within the upper five feet of existing grades, transitioning to very dense, cemented, and competent glacial till or native Renton Formation bedrock at depth. The presence of shallow perched groundwater seepage should be anticipated within site excavations. Seattle LLL, LLC ES-9099 July 18, 2023 Page 11 Earth Solutions NW, LLC The following Federal Occupation Safety and Health Administration and Washington Industrial Safety and Health Act soil classifications and maximum allowable temporary slope inclinations may be used: Areas exposing groundwater seepage 1.5H:1V (Type C) Loose soil and fill 1.5H:1V (Type C) Medium dense to dense soil 1H:1V (Type B) Dense to very dense native soil or bedrock 0.75H:1V (Type A) Groundwater seepage should be anticipated during excavation activities, particularly if excavations take place during the wet season. An ESNW representative should observe temporary excavations to evaluate the presence of groundwater seepage. If seepage is not observed, steeper temporary slope inclinations may be feasible, particularly where the native, unweathered, and cemented “hardpan” glacial till deposits are exposed within relatively large, open excavations. As previously noted, coal mine related hazards found during development activities shall be immediately reported to both ESNW and the Development Services Division for remediation. An ESNW representative should observe temporary and permanent slopes to confirm the slope inclinations are suitable for the exposed soil conditions and to provide additional excavation and slope recommendations, as necessary. If the recommended temporary slope inclinations cannot be achieved, temporary shoring may be necessary to support excavations. Permanent slopes should be planted with vegetation to both enhance stability and minimize erosion and should maintain a gradient of 2H:1V or flatter. 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. Structural fill placed and compacted during site grading activities should meet the following specifications and guidelines: Structural fill material Granular soil Moisture Content At or slightly above optimum Relative compaction (minimum) 95 percent (Modified Proctor) Loose lift thickness (maximum) 12 inches The in-situ mineral soils may not be suitable for use as structural fill unless the soil is at (or slightly above) the optimum moisture content at the time of placement and compaction. Soil shall not be placed dry of the optimum moisture content and should be evaluated by ESNW during construction. Seattle LLL, LLC ES-9099 July 18, 2023 Page 12 Earth Solutions NW, LLC If native soil is placed below the optimum moisture content, settlement will likely occur during periods of wet weather. As such, structural fill soils should be properly moisture conditioned, as necessary, to ensure acceptability of the soil moisture content at the time of placement and compaction. Native soil will be difficult or impossible to use as structural fill during extended wet weather conditions. In this respect, moisture conditioning or treatment of the soils may be necessary at some locations prior to use as structural fill. With respect to underground utility installations and backfill, local jurisdictions may dictate the soil type(s) and compaction requirements. Unsuitable material or debris must be removed from structural areas if encountered. In-situ and Imported Soil The in-situ soils encountered at the subject site have a high sensitivity to moisture and were generally in a moist to wet condition at the time of exploration. Soils anticipated to be exposed on site will degrade rapidly if exposed to wet weather and construction traffic. Compaction of the soil to the levels necessary for use as structural fill may be difficult or impossible during wet weather conditions, and are likely to be over the optimum moisture content immediately after excavation. Soils encountered during site excavations that are excessively over the optimum moisture content will likely require aeration or treatment prior to placement and compaction. Conversely, soils that are substantially below the optimum moisture content will require moisture conditioning through the addition of water prior to use as structural fill. An ESNW representative should be contacted to evaluate the suitability of the in-situ soil for use as structural fill at the time of construction. Imported soil intended for use as structural fill should be evaluated by ESNW during construction. The imported soil must be workable to the optimum moisture content, as determined by the Modified Proctor Method (ASTM D1557), at the time of placement and compaction. 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). Wet Season Grading Earthwork activities that occur during the wet season may require additional measures to protect both structural subgrades and soil intended for use as structural fill. Site-specific recommendations can be provided at the time of construction and may include leaving cut areas several inches above design subgrade elevations, covering working surfaces with crushed rock, protecting structural fill soil from adverse moisture conditions, and additional TESC recommendations. ESNW can assist in obtaining a wet season grading permit if required by the governing jurisdiction. Seattle LLL, LLC ES-9099 July 18, 2023 Page 13 Earth Solutions NW, LLC Subgrade Preparation Following site stripping, ESNW should be contacted to observe the subgrade to confirm soil conditions are as anticipated and to provide supplementary recommendations for subgrade preparation, as necessary. Such supplementary recommendations for subgrade improvement may be provided at the time of construction and would likely include further mechanical compaction or overexcavation and replacement with suitable structural fill. Void Space Restoration The process of removing the existing structures may produce voids where old foundations are removed and where crawl space areas may have been present. Complete restoration of voids from old foundation areas must be executed as part of the subgrade preparation activities. The following guidelines for preparing the subgrade where existing structures have been removed should be incorporated into the final design: Where voids and related demolition disturbances extend below planned subgrade elevations, restoration of these areas should be completed. Structural fill should be used to restore voids or unstable areas resulting from the removal of existing structural elements. Recompact, or overexcavate and replace, areas of existing fill exposed throughout areas of future subgrade. Overexcavations should extend into competent native soils and structural fill should be utilized to restore subgrade elevations, as necessary. ESNW should confirm subgrade conditions, as well as the required level of re-compaction and/or overexcavation and replacement, during site preparation activities. ESNW should also evaluate the overall suitability of prepared subgrade areas following site preparation activities. Grading and Excavations in Bedrock Site grading and excavations may extend into the underlying and relatively competent sandstone bedrock. The upper surface of Renton Formation bedrock will likely be rippable with conventional equipment. However, areas of increased difficulty should be anticipated. In our opinion, the contractor should be prepared with tiger-teeth-fitted excavator buckets for excavations that extend into the sandstone bedrock, particularly in the western portion of the site where bedrock was encountered within about eight feet of the existing ground surface. ESNW would be available during initial mass grading activities to further evaluate rippability of the native bedrock with the grading contractor, if requested. Foundations Typical two- to three-story residential structures constructed on this site can be supported on conventional spread and continuous footings bearing on competent (undisturbed) native soil, recompacted native soil, or new structural fill placed directly on a competent subgrade. Provided site earthwork activities are completed in accordance with our recommendations, suitable soil conditions should be exposed beginning at depths of about two to three feet bgs. Seattle LLL, LLC ES-9099 July 18, 2023 Page 14 Earth Solutions NW, LLC An ESNW representative should be requested to confirm the suitability of foundation subgrades at the time of construction. If deemed necessary, the undisturbed native soils may be compacted in situ provided the soil is at or slightly above the optimum moisture content. Due to the high moisture sensitivity of the site soils, foundation subgrade areas should be protected from wet weather or areas of remediation should be anticipated; a layer of crushed rock can be considered to protect foundation subgrade areas. If structural building pads are disturbed during wet weather, remediation measures such as overexcavation and replacement with rock may be necessary in some areas. Provided the structure(s) will be supported as described above, the following parameters may be used for design of the new foundations: Allowable soil bearing capacity 2,500 psf Passive earth pressure 300 pcf Coefficient of friction 0.40 A one-third increase in the allowable soil bearing capacity can be assumed for short-term wind and seismic loading conditions. The passive earth pressure and coefficient of friction values include a safety factor of 1.5. With structural loading as expected, total settlement in the range of one inch is anticipated, with differential settlement of about one-half inch. Most of the anticipated settlement should occur during construction as dead loads are applied. Retaining Walls Retaining walls must be designed to resist earth pressures and applicable surcharge loads. The following parameters may be used for retaining wall design: Active earth pressure (unrestrained condition) 35 pcf At-rest earth pressure (restrained condition) 55 pcf Traffic surcharge (passenger vehicles) 70 psf (rectangular distribution) Passive earth pressure 300 pcf Coefficient of friction 0.40 Seismic surcharge 8H psf* * Where H equals the retained height (in feet). The passive earth pressure and coefficient of friction values include a safety factor of 1.5. Additional surcharge loading from adjacent foundations, sloped backfill, or other loads should be included in the retaining wall design. Seattle LLL, LLC ES-9099 July 18, 2023 Page 15 Earth Solutions NW, LLC Retaining walls should be backfilled with free-draining material that extends along 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 a less permeable soil, if desired. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design. 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 6. 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 with respect to earthquake loads. Based on the soil and bedrock conditions encountered at the exploration 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) 1.427 Mapped 1-second period spectral response acceleration, S1 (g) 0.486 Short period site coefficient, Fa 1.200 Long period site coefficient, Fv 1.500 Adjusted short period spectral response acceleration, SMS (g) 1.712 Adjusted 1-second period spectral response acceleration, SM1 (g) 0.728 Design short period spectral response acceleration, SDS (g) 1.142 Design 1-second period spectral response acceleration, SD1 (g) 0.486 * Assumes very dense native soil and bedrock conditions, encountered to a maximum depth of 80 feet bgs during the May 2023 field exploration, remain very dense to at least 100 feet bgs. As indicated in the table footnote, several of the seismic design values provided above are dependent on the assumption that site-specific ground motion analysis (per Section 11.4.8 of ASCE 7-16) will not be required for the subject project. ESNW recommends the validity of this assumption be confirmed at the earliest available opportunity during the planning and early design stages of the project. Further discussion between the project structural engineer, the project owner, and ESNW may be prudent to determine the possible impacts to 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. Seattle LLL, LLC ES-9099 July 18, 2023 Page 16 Earth Solutions NW, LLC Liquefaction is a phenomenon that can occur within a soil profile as a result of an intense ground shaking or loading condition. Most commonly, liquefaction is caused by ground shaking during an earthquake. Soil profiles that are loose, cohesionless, and present below the groundwater table are most susceptible to liquefaction. During the ground shaking, the soil contracts, and porewater pressure increases. The increased porewater pressure occurs quickly and without sufficient time to dissipate, resulting in water flowing upward to the ground surface and a liquefied soil condition. Soil in a liquefied condition possesses very little shear strength in comparison to the drained condition, which can result in a loss of foundation support for structures. In our opinion, and consistent with the depiction on the referenced liquefaction susceptibility map, site susceptibility to liquefaction may be considered very low to negligible. The absence of a shallow groundwater table and the relatively dense and cemented characteristics of the native soil and bedrock were the primary bases for this opinion. Slab-on-Grade Floors Slab-on-grade floors should be supported on a firm and unyielding subgrade consisting of competent native soil or at least 12 inches of new structural fill. Unstable or yielding areas of the subgrade should be recompacted or overexcavated and replaced with suitable structural fill prior to slab construction. A capillary break consisting of a minimum of four inches of free-draining crushed rock or gravel should be placed below the slab. The free-draining material should have a fines content of 5 percent or less defined as the percent passing the number 200 sieve, based on the minus three- quarter-inch fraction. In areas where slab moisture is undesirable, installation of a vapor barrier below the slab should be considered. If used, the vapor barrier should consist of a material specifically designed to function as a vapor barrier and should be installed in accordance with the manufacturer’s specifications. Utility Support and Trench Backfill The native soils observed at the subsurface exploration locations are generally suitable for support of utilities. Utility trench excavations may encounter bedrock; see above for a discussion regarding excavations into bedrock. Use of the native soil as structural backfill in the utility trench excavations will depend on the in- situ moisture content at the time of placement and compaction. If native soil is placed below the optimum moisture content, settlement will likely occur once wet weather impacts the trenches. As such, backfill soils should be properly moisture conditioned, as necessary, to ensure acceptability of the soil moisture content at the time of placement and compaction. Native soil will be difficult or impossible to use as utility trench backfill during extended wet weather conditions. In this respect, moisture conditioning or treatment of the soils may be necessary at some locations prior to use as structural fill. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report or to the applicable requirements of the presiding jurisdiction. Seattle LLL, LLC ES-9099 July 18, 2023 Page 17 Earth Solutions NW, LLC 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 proof rolling 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 or yielding subgrade conditions will require remedial measures, such as overexcavation and/or placement of thick crushed rock or structural fill sections, prior to pavement. We anticipate new pavement sections will be subjected primarily to passenger vehicle traffic. For lightly loaded pavement areas subjected primarily to passenger vehicles, the following preliminary pavement sections may be considered: A minimum of two inches of hot-mix asphalt (HMA) placed over four inches of crushed rock base (CRB). A minimum of two inches of HMA placed over three inches of asphalt-treated base (ATB). An ESNW representative should be requested to observe subgrade conditions prior to placement of CRB or ATB. As necessary, supplemental recommendations for achieving subgrade stability and drainage can be provided. 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. 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. If on-site roads are constructed with an inverted crown, additional drainage measures may be recommended to assist in maintaining road subgrade and pavement stability. Drainage Groundwater seepage will likely be encountered within site excavations depending on the time of year grading operations take place. Temporary measures to control surface water runoff and groundwater during construction would likely involve passive elements such as interceptor trenches, interceptor swales, and sumps. ESNW should be consulted during preliminary grading to identify areas of seepage and provide recommendations to reduce the potential for seepage- related instability. The contractor should be prepared to manage areas of groundwater seepage in excavations. 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, a foundation drain should be installed along building perimeter footings. A typical foundation drain detail is provided on Plate 7. Seattle LLL, LLC ES-9099 July 18, 2023 Page 18 Earth Solutions NW, LLC Infiltration Feasibility Based on conditions encountered during the fieldwork, in our opinion, full infiltration should be considered infeasible from a geotechnical standpoint. Near surface soils consisted of very dense, weakly cemented glacial till deposits with fines contents between about 42 and 58 percent. The high relative density, high fines content, and weak cementation of native glacial till soils will severely limit in-situ hydraulic conductivity. In our opinion, the native glacial till soils and underlying bedrock should be considered impermeable for design purposes. If necessary to satisfy project objectives, limited infiltration applications may be feasible within the upper weathered soil horizon. However, depending on the extent of proposed grade modifications (i.e., grade cuts and fills), the upper weathered soils are unlikely to remain in an undisturbed condition, precluding the design and implementation of shallow LID elements. ESNW would be pleased to further investigate the feasibility of shallow LID elements, upon request. Preliminary Stormwater Vault Design Based on the presence of impermeable glacial till and bedrock deposits, we anticipate a stormwater detention vault will likely be utilized for stormwater management in the western portion of the site. Vault foundations should be supported on very dense, undisturbed native soil, bedrock, or crushed rock placed on a competent subgrade surface. Based on observations made at boring location B-1 (within Tract A), vault excavations would be expected to expose dense glacial till deposits from the surface extending to roughly eight feet bgs. Deeper than eight feet, vault excavations will likely expose slightly weathered, competent Renton Formation sandstone bedrock. Minor perched groundwater seepage may be exposed depending on the time of year excavations occur. Storm vault designs must incorporate adequate buffer space from property boundaries such that temporary excavations to construct the vault structure can be successfully completed. Perimeter drains should be installed around the vault and conveyed to an approved discharge point. The presence of perched groundwater seepage should be anticipated during excavation activities for the vault; however, buoyancy is not expected to influence the vault design. In general, and in anticipation for groundwater seepage to be present within the vault excavation, Type A and C soils (as described in the Excavations and Slopes section of this report) should be expected. Seattle LLL, LLC ES-9099 July 18, 2023 Page 19 Earth Solutions NW, LLC The following parameters can be used for stormwater vault design: Allowable soil bearing capacity 5,000 psf (very dense glacial till or competent Renton Formation Bedrock) 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. The passive earth pressure and coefficient of friction values include a safety factor of 1.5. The vault walls should be backfilled with free-draining material or suitable common earth if a sheet drain material is used. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A perforated 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 portion of the vault below the drain should be designed to include hydrostatic pressure. Design values accounting for hydrostatic pressure are included above. ESNW should observe grading operations for the vault and the subgrade conditions prior to concrete forming and pouring to confirm conditions are as anticipated, and to provide supplemental recommendations as necessary. Additionally, ESNW should be contacted to review final vault designs to confirm that appropriate geotechnical parameters have been incorporated into the design. We anticipate native soil will be used as vault backfill. Detention vault backfill should conform to the specifications of structural fill previously detailed in this report. The native soil is moisture sensitive and will settle once impacted by wet weather if placed below the optimum moisture content. ESNW recommends placing the native soil at or slightly above the optimum moisture content. Native soil placed substantially above the optimum moisture content will require additional time or remediation prior to supporting a structure. Seattle LLL, LLC ES-9099 July 18, 2023 Page 20 Earth Solutions NW, LLC LIMITATIONS This study has been prepared for the exclusive use of Seattle LLL, LLC, 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. A warranty is neither expressed nor implied. Variations in the soil and groundwater conditions observed at the exploration 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 final project plans with respect to the geotechnical recommendations provided in this report. ESNW should also be retained to provide testing and consultation services as needed during design and construction phases of the project. Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked BCS Date June 2023 Date 06/07/2023 Proj.No.9099 Plate 1 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Vicinity Map Talbot Road 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 Plate Proj.No. Date Checked DrawnEarthSolutionsNWLLC GeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCBoringLocationPlanTalbotRoadPropertyRenton,WashingtonNORTHLEGEND Approximate Location of ESNW Boring,Proj.No. ES-9099,May 2023 Subject Site Existing Building Proposed Lot Number 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. 0 2 5 5 0 1 0 0 Sc ale in Feet1"=5 0 ' MRS BCS 06/15/2023 9099 2 B-1 1 B-2 B-3 B-4 B-5 B-1 TALBOT ROAD S.TALBOT ROAD S.1 2 3 4 5 6 Tract A 170 180 190170 180 190SHATTUCK AVENUE S. Plate Proj.No. Date Checked DrawnEarthSolutionsNWLLC GeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCCAM BCS 06/15/2023 9099 3 Reference: Geologic Map of The Renton Quadrangle, King County,Washington By D.R.Mullineaux 1965 GeologicMapTalbotRoadPropertyRenton,WashingtonNORTH 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. Approximate Site Location Plate Proj.No. Date Checked DrawnEarthSolutionsNWLLC GeotechnicalEngineering,ConstructionObservation/TestingandEnvironmentalServicesEarthSolutionsNWLLCEarthSolutionsNWLLCCAM BCS 06/15/2023 9099 4 Reference: Geologic Structure Map of Renton Coal Mine, Renton Coal Company,Renton,Washington. Washington Department of Natural Resources, Historical Coal Mine Map K32 A HistoricalCoalMineMapK32ATalbotRoadPropertyRenton,WashingtonNORTH 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. Approximate Site Location Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn CAM Checked BCS Date June 2023 Date 06/15/2023 Proj.No.9099 Plate 5 Earth Solutions NWLLCEarthSolutionsNWLLC EarthSolutions NW LLC Approximate Site LocationPotentialMining Related Disturbances 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. NORTH LiDAR-Based Shaded Relief Map Talbot Road Property Renton,Washington Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked BCS Date June 2023 Date 06/15/2023 Proj.No.9099 Plate 6 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 Talbot Road Property Renton,Washington Geotechnical Engineering,Construction Observation/Testing and Environmental Services Drawn MRS Checked BCS Date June 2023 Date 06/15/2023 Proj.No.9099 Plate 7 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 Talbot Road Property Renton,Washington Earth Solutions NW, LLC Appendix A Subsurface Exploration Logs ES-9099 Subsurface conditions on site were explored between May 15 and May 17, 2023, by advancing five borings using a track-mounted mud-rotary drill rig and operators retained by ESNW. The approximate locations of the exploration sites are illustrated on Plate 2 of this study. The exploration logs are provided in this Appendix. The borings were advanced to a maximum depth of about 80 feet bgs. The final logs represent the interpretations of the field logs and the results of laboratory analyses. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. >12%Fines<5%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) 165.0 SS SS 100 100 15-22-26 (48) 11-20-24 (44) MC = 13.4 Fines = 49.2 MC = 20.0 SM Bedrock Gray silty SAND, dense, moist [USDA Classification: slightly gravelly LOAM] -light iron oxide staining -minor scattered fine gravel -machine chatter SANDSTONE (Renton Formation Bedrock), moderate yellowish brown (10YR 6/6), medium to coarse grained, slightly weathered (Grade II), very weak to moderately weak rock (R1 to R2) -heavily oxidized to about 30' -mm scale laminations -poorly graded medium to coarse sand grains with silty matrix 8.0DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 1 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 143.0 SS SS SS 100 100 100 17-50/5" 22-22-32 (54) 50/6" MC = 16.6 MC = 19.5 MC = 19.5 Bedrock SANDSTONE (Renton Formation Bedrock), moderate yellowish brown (10YR 6/6), medium to coarse grained, slightly weathered (Grade II), very weak to moderately weak rock (R1 to R2) (continued) -smooth, consistent rig behavior to BOH -becomes moderate yellowish brown (10YR 6/6) and light gray (N7) -trace coal present in mm scale laminations and sand-sized clasts -trace coal present in mm scale laminations 30.0DEPTH(ft)15.0 17.5 20.0 22.5 25.0 27.5 30.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 2 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG SS SS SS 90 100 91 42-50/4" 24-50/6" 40-50/5" MC = 17.3 MC = 16.2 MC = 18.0 Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2) -sample is easily friable -trace coal in sand-sized clasts -easily friableDEPTH(ft)30.0 32.5 35.0 37.5 40.0 42.5 45.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 3 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 118.0 115.0 SS SS SS 100 0 67 25-30- 50/6" 50/6" 12-12-15 (27) MC = 16.4 MC = 27.8 Bedrock ML Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2) (continued) -minor scattered coal fragments -inch scale dark brown organic beds -consistent drilling behavior -no recovery Gray SILT, medium dense, wet SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R1 to R2) 55.0 58.0DEPTH(ft)45.0 47.5 50.0 52.5 55.0 57.5 60.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 4 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG SS SS SS 100 100 100 50/3" 32-50/4" 50/3" MC = 12.4 MC = 15.5 MC = 13.4 Bedrock SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R1 to R2) (continued) -trace fine sand -very slow, consistent drilling to BOH -weak to moderately lithified -retool rig with "drag bit", slightly increased drilling efficiencyDEPTH(ft)60.0 62.5 65.0 67.5 70.0 72.5 75.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 5 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 92.5 SS SS 100 100 50/2" 50/1" MC = 11.2 MC = 22.1 Bedrock SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R1 to R2) (continued) Boring terminated at 80.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with grout. 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. 80.5DEPTH(ft)75.0 77.5 80.0 SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/15/23 COMPLETED 5/15/23 GROUND WATER LEVEL: GROUND ELEVATION 173 ft LATITUDE 47.46082 LONGITUDE -122.21248 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 6 OF 6 BORING NUMBER B-1 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 160.0 SS SS 100 100 21-31-45 (76) 50/4" MC = 6.0 Fines = 57.8 MC = 13.2 ML Gray sandy SILT, medium dense, moist -rig chatter, becomes very dense [USDA Classification: slightly gravelly LOAM] -light iron oxide staining -minor scattered fine gravel -significant machine chatter 15.0DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 175 ft LATITUDE 47.46107 LONGITUDE -122.21214 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 1 OF 3 BORING NUMBER B-2 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 150.0 SS SS SS 89 100 100 18-32-46 (78) 50/6" 50/2" MC = 17.8 MC = 17.3 MC = 10.4 Bedrock Bedrock SANDSTONE (Renton Formation Bedrock), moderate yellowish brown (10YR 6/6) and light gray (N7), medium to coarse grained, slightly weathered (Grade II), very weak to moderately weak rock (R1 to R2) -relatively friable rock -slow drilling SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R0 to R1) -moderately to strongly lithified -very slow, consistent drilling to BOH 25.0DEPTH(ft)15.0 17.5 20.0 22.5 25.0 27.5 30.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 175 ft LATITUDE 47.46107 LONGITUDE -122.21214 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 2 OF 3 BORING NUMBER B-2 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 134.5 SS SS SS 100 100 100 50/5" 50/3" 50/3" MC = 13.7 MC = 11.4 MC = 14.9 Bedrock SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R0 to R1) (continued) -moderately abundant coal (approximately 20 to 40 percent of sample) present in mm scale laminations -laminations are near vertical in orientation -minor coal (approximately 10 o 15 percent of sample) present in mm scale laminations -laminations are near vertical in orientation Boring terminated at 40.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with grout. 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. 40.5DEPTH(ft)30.0 32.5 35.0 37.5 40.0 SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 175 ft LATITUDE 47.46107 LONGITUDE -122.21214 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 3 OF 3 BORING NUMBER B-2 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 172.0 SS SS 100 100 4-6-10 (16) 27-50/3" MC = 18.9 Fines = 42.3 MC = 12.7 SM Bedrock Gray silty SAND, medium dense, moist [USDA Classification: slightly gravelly fine sandy LOAM] -minor scattered fine gravel -light iron oxide staining SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2) -smooth consistent rig behavior to BOH 10.0DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 182 ft LATITUDE 47.46083 LONGITUDE -122.21201 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 1 OF 4 BORING NUMBER B-3 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG SS SS SS 92 100 67 20-50/6" 50/5" 17-18-23 (41) MC = 14.3 MC = 17.9 MC = 17.7 Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2) (continued) -near vertical, mm scale coal laminations 0-15% coal -slow drilling, retool rig from tricone bit to drag bit -easily friable -near vertical / steeply diping mm scale coal laminations 0-15% coalDEPTH(ft)15.0 17.5 20.0 22.5 25.0 27.5 30.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 182 ft LATITUDE 47.46083 LONGITUDE -122.21201 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 2 OF 4 BORING NUMBER B-3 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG SS SS SS 100 100 100 50/3" 50/5" 50/5" MC = 18.2 MC = 16.5 MC = 18.2 Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderately weak rock (R1 to R2) (continued) -trace coal present in mm scale, near vertical laminationsDEPTH(ft)30.0 32.5 35.0 37.5 40.0 42.5 45.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 182 ft LATITUDE 47.46083 LONGITUDE -122.21201 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 3 OF 4 BORING NUMBER B-3 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 136.5 SS 100 50/3"MC = 15.3 Bedrock Boring terminated at 45.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with grout. 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. 45.5DEPTH(ft)45.0 SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/16/23 COMPLETED 5/16/23 GROUND WATER LEVEL: GROUND ELEVATION 182 ft LATITUDE 47.46083 LONGITUDE -122.21201 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 4 OF 4 BORING NUMBER B-3 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 171.0 SS SS 67 100 14-14-19 (33) 25-41- 50/5" MC = 17.4 Fines = 48.4 MC = 12.7 SM Brown silty SAND, dense, moist [USDA Classification: slightly gravelly LOAM] -light iron oxide staining -trace scattered fine gravel -becomes gray, very dense -reduced oxide staining, weakly cemented -significant drilling resistance -rig chatter 15.0DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 186 ft LATITUDE 47.46091 LONGITUDE -122.21164 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 1 OF 4 BORING NUMBER B-4 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 161.0 SS SS SS 100 100 100 36-45- 50/5" 29-35-47 (82) 50/5" MC = 16.6 Fines = 47.7 MC = 13.4 MC = 14.9 SM Bedrock Brown silty SAND, very dense, moist [USDA Classification: slightly gravelly LOAM] -scattered fine to medium gravel in cemented, silty sand matrix -scattered fine gravel -weakly cemented SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderate weak rock (R1 to R2) -friable rock 25.0DEPTH(ft)15.0 17.5 20.0 22.5 25.0 27.5 30.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 186 ft LATITUDE 47.46091 LONGITUDE -122.21164 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 2 OF 4 BORING NUMBER B-4 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 146.0 SS SS SS 100 100 100 50/4" 31-50/5" 50/3" MC = 13.7 MC = 15.7 MC = 13.2 Bedrock Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderate weak rock (R1 to R2) (continued) -mm scale coal laminations -bedding plane is near vertical -decreasing grain size SILTSTONE (Renton Formation Bedrock), light gray (N7), fine grained, fresh (Grade I), extremely to very weak rock (R0 to R1) -trace coal present in mm scale laminations -laminations are near vertical in orientation -increasing sand content 40.0DEPTH(ft)30.0 32.5 35.0 37.5 40.0 42.5 45.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 186 ft LATITUDE 47.46091 LONGITUDE -122.21164 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 3 OF 4 BORING NUMBER B-4 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 140.5 SS 100 50/3"MC = 20.0 Bedrock Boring terminated at 45.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with grout. 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. 45.5DEPTH(ft)45.0 SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 186 ft LATITUDE 47.46091 LONGITUDE -122.21164 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 4 OF 4 BORING NUMBER B-4 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 177.0 SS SS 39 100 7-7-6 (13) 25-50/6" MC = 19.4 MC = 12.2 Fines = 48.1 SM Gray silty SAND, medium dense, moist -minor scattered fine to medium gravel [USDA Classification: slightly gravelly LOAM] -becomes very dense, weakly cemented 15.0DEPTH(ft)0.0 2.5 5.0 7.5 10.0 12.5 15.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 192 ft LATITUDE 47.46099 LONGITUDE -122.21118 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 1 OF 4 BORING NUMBER B-5 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 162.0 SS SS SS 100 100 82 50/6" 50/5" 40-50/5" MC = 11.4 MC = 11.1 MC = 11.1 SM Gray silty SAND, very dense, moist -slight rig chatter -trace sand-sized coal fragments incorporated into glacial till deposit 30.0DEPTH(ft)15.0 17.5 20.0 22.5 25.0 27.5 30.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 192 ft LATITUDE 47.46099 LONGITUDE -122.21118 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 2 OF 4 BORING NUMBER B-5 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG SS SS SS 100 100 100 50/5" 50/4" 50/6" MC = 12.6 MC = 14.7 MC = 16.5 Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderate weak rock (R1 to R2) -friable rock -poorly graded medium to coarse sand grains in silty sand matrixDEPTH(ft)30.0 32.5 35.0 37.5 40.0 42.5 45.0 (Continued Next Page)SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 192 ft LATITUDE 47.46099 LONGITUDE -122.21118 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 3 OF 4 BORING NUMBER B-5 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG 141.5 SS SS 100 100 50/5" 50/4" MC = 15.9 MC = 16.3 Bedrock SANDSTONE (Renton Formation Bedrock), light gray (N7), medium to coarse grained, fresh (Grade I), very weak to moderate weak rock (R1 to R2) (continued) -massive (no bedding) Boring terminated at 50.5 feet below existing grade. No groundwater encountered during drilling. Boring backfilled with grout. 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. 50.5DEPTH(ft)45.0 47.5 50.0 SAMPLE TYPENUMBERDRILLING CONTRACTOR Holocene Drilling DATE STARTED 5/17/23 COMPLETED 5/17/23 GROUND WATER LEVEL: GROUND ELEVATION 192 ft LATITUDE 47.46099 LONGITUDE -122.21118 LOGGED BY BCS CHECKED BY HTW NOTES SURFACE CONDITIONS Field grass AT TIME OF DRILLINGAT TIME OF DRILLING AFTER DRILLING PAGE 4 OF 4 BORING NUMBER B-5 PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GENERAL BH / TP / WELL - 9099.GPJ - GINT US.GDT - 7/18/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 RECOVERY %BLOWCOUNTS(N VALUE)TESTS U.S.C.S.MATERIAL DESCRIPTION GRAPHICLOG Earth Solutions NW, LLC Appendix B Laboratory Test Results ES-9099 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 49.2 57.8 42.3 48.4 47.7 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Gray Slightly Gravelly Loam. USCS: SM. USDA: Gray Slightly Gravelly Loam. USCS: Sandy ML. USDA: Gray Slightly Gravelly Fine Sandy Loam. USCS: SM. USDA: Brown Slightly Gravelly Loam. USCS: SM. USDA: Gray Slightly Gravelly Loam. USCS: SM. 6 60 PERCENT FINER BY WEIGHTD10 0.143 0.089 0.17 0.151 0.167 GRAIN SIZE DISTRIBUTION 100 LL B-01 B-02 B-03 B-04 B-04 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 19 19 19 19 19 %Silt B-01 B-02 B-03 B-04 B-04 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 5.0ft. 5.0ft. 5.0ft. 5.0ft. 15.0ft. 5.00ft. 5.00ft. 5.00ft. 5.00ft. 15.00ft. PL PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GRAIN SIZE USDA ES-9099 TALBOT ROAD PROPERTY.GPJ GINT US LAB.GDT 6/2/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 0.0010.010.1110100 3 D100 140 Specimen Identification 1 fine 6 HYDROMETER 304 48.1 101/2 COBBLES Specimen Identification 4 coarse 20 401.5 8 14 USDA: Gray Slightly Gravelly Loam. USCS: SM. 6 60 PERCENT FINER BY WEIGHTD10 0.158 GRAIN SIZE DISTRIBUTION 100 LL B-05 3/4 U.S. SIEVE OPENING IN INCHES U.S. SIEVE NUMBERS GRAVEL SAND 19 %Silt B-05 2 2003 Cc CuClassification %Clay 16 PID60 D30 coarse SILT OR CLAYfinemedium GRAIN SIZE IN MILLIMETERS 3/8 50 10.0ft. 10.00ft. PL PROJECT NUMBER ES-9099 PROJECT NAME Talbot Road Property GRAIN SIZE USDA ES-9099 TALBOT ROAD PROPERTY.GPJ GINT US LAB.GDT 6/2/23Earth Solutions NW, LLC 15365 N.E. 90th Street, Suite 100 Redmond, Washington 98052 Telephone: 425-449-4704 Fax: 425-449-4711 Earth Solutions NW, LLC Report Distribution ES-9099 Seattle LLL, LLC Attention: Lili Lu D.R. Strong Consulting Engineers Attention: Maher Joudi, P.E. WASHINGTON FORESTRY CONSULTANTS, INC. FORESTRY AND VEGETATION MANAGEMENT SPECIALISTS W F C I O: 360/943-1723 C: 360/561-4407 9136 Yelm Hwy SE Olympia, WA 98513 URBAN/RURAL FORESTRY • TREE APPRAISAL • TREE RISK ASSESSMENT RIGHT-OF-WAYS • VEGETATION MANAGEMENT • FOREST/TREE MGT. PLANS • EXPERT TESTIMONY Member of International Society of Arboriculture and Society of American Foresters - Preliminary Tree Protection Plan- TALBOT ROAD PROJECT 2103 Talbot Road South Renton, WA 98055 Prepared for: Lili Lu / 吕莉莉 CEO Global Land LLC Prepared by: Washington Forestry Consultants, Inc. Date of Report: June 26, 2023 Introduction The project proponent is planning to construct a new 6-lot short plat on one parcel totaling 1.39- acres at 2103 Talbot Road South in Renton. The proponent has retained WFCI to: • Evaluate and inventory all trees on the site pursuant to the requirements of the City of Renton 4-4-130 Tree Retention and Land Clearing Regulations. • Make recommendations for retention of significant trees, along with required protection and cultural measures. Observations Methodology WFCI has evaluated all trees with a caliper of at least 6" diameter at breast height (DBH), except alder or cottonwood trees, which qualify as significant trees with a caliper of 8" or greater. To be a significant tree, it must have a condition rating of Fair or better. Trees rated as Poor, Very Poor, or Dead or are defective, diseased and/or in decline and are not long-term trees and are not considered to be significant trees. All off-site trees with driplines or root protection zones (RPZ’s) encroaching the site were assessed as well. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 2 The tree evaluation phase used methodology developed by Nelda Matheny and Dr. James Clark in their 1998 publication Trees and Development: A Technical Guide to Preservation of Trees during Land Development. Site Description The project site consists of one 1.39-acre parcel, # 7222000175. The cover type on the site is dominated by a grass pasture area in the southern half of the parcel. A single-family home and associated outbuildings are in the northern half. The topography moderately slopes to the west from the house area. The site has a westerly aspect. There are high voltage transmission powerlines that run along the west property line. The project is bordered by single-family homes to the north and south, Talbot Road S. to the east, and Shattuck Avenue S. to the west. Soils Description According to the USDA Natural Resource Conservation Service soil survey the soil type in the project area is the Beausite gravelly sandy loam, a moderately deep, well-drained soil. It is formed as glacial till over residuum from sandstone. Permeability is moderately high to high. Available water capacity is low. Lithic bedrock occurs at a depth of 24 to 40 inches. The effective rooting depth for trees is to the bedrock. The potential for windthrow of trees is slight under normal conditions. New trees require irrigation for establishment. Figure 1. Talbot Road Project Soils Map BeC – Beausite gravelly sandy loam Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 3 Existing Tree Conditions There is one forest cover type on the project area for the purpose of description. The aerial photo of the project, with tree locations, is shown in Attachment 1. Type I. -- This cover type covers the entire project site. There are a total of 26 trees in the type. There are introduced trees planted around the home and naturally seeded native trees growing on the perimeters of the site. The size of significant trees ranges from 6 inches to 30 inches in diameter at breast height (DBH). Tree species include apple (Malus spp.), bigleaf maple (Acer macrophyllum), cherry (Prunus spp.), cypress (Cupressus spp.), flowering dogwood (Cornus florida), hawthorn (Crataegus monogyna), English holly (Ilex aquifolium), and Oregon ash (Fraxinus latifolia). Tree conditions on the site range from ‘Very Poor’ to ‘Good,’ with just over half the trees (54%) described as being in ‘Poor’ or worse condition. The high number of trees in poor condition is due to trees under the overhead powerlines that have been topped multiple times for clearance. The topping has created areas of decay in the tree’s upper canopies. The trees should be removed and the area re-planted with a small scale tree that will not need continual clearance pruning. Table 1. Summary of trees on Talbot Road Project Site. Species DBH Range (in.) Condition Range Total # of Trees # of Healthy Trees # of Unhealthy Trees* Species Composition of the Stand Apple 6 – 21 Very Poor - Good 6 4 2 23 Bigleaf Maple 15 – 25 Very Poor – Poor 3 0 3 12 Cherry 6 – 17 Poor – Good 4 1 3 15 Cypress 19 – 20 Good 2 2 0 8 Flowering Dogwood 8 Good 1 1 0 3 Hawthorn 6 – 14 Good 3 3 0 12 Holly 7 – 18 Poor – Good 2 1 1 8 Oregon Ash 6 – 30 Very Poor – Poor 5 0 5 19 Sum 6 - 30 Very Poor - Good 26 12 14 100% *Trees rated as dead, very poor, or poor. Twelve of the 26 significant trees could be potentially retained on this site when only tree health is considered. The remaining trees are in poor health or have been topped. One holly tree that has some top dieback but will be saved as part of the project. There are 3 Landmark sized trees on the project site. Only one of those trees is healthy and would make good long-term trees to save. The one healthy Landmark tree is proposed to be retained. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 4 The understory vegetation throughout the type is grass, weeds, and other planted shrubs in the landscape. Photo 1: View of trees 1 – 9 on the Talbot Road Project Site. Off-site Impacts There are no off-site trees that will be impacted from grading on the project. A few small landscape trees have branches that overhang the site. The branches can be pruned back to the property line without causing damage to the trees. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 5 Discussion Potential for Tree Retention There are four trees that have the potential to be retained with this site plan. All the trees are located on lot 6 around the existing home that will be saved as part of the project. The one healthy Landmark tree is being saved. The remaining trees are all under the footprints of improvements. Tree Density Calculations Title 4-4-130H(a) of the Renton Municipal Code (RMC) requires 30% of the significant trees on the site to be retained. There are a total of 26 significant sized trees on the parcel. After allowed tree deductions 16 trees remain for calculating the 30% requirement. A total of 5 significant trees will need to be retained in the project area to meet the requirement. Total # of Significant Trees: 26 Trees # of High Risk Significant Trees: 0 Trees # of Trees in the Public Rights-of-Ways: 10 Trees # of Significant Trees After Deductions: 16 Trees # of Significant Trees Required to be Saved (30% of 16 Trees): 5 Trees # of Significant Trees Planned to be Saved 4 Trees Shortfall of Significant Tree Requirement 1 Tree Additionally, RMC4-4-130H(b) requires a minimum tree credit density of 30 tree credits per acre of net developable acreage. The following is a summary of the projected tree density requirements: Gross Site Acreage: 1.39 Acres Designated Public Rights-of-way: 0.0 Acres Net Developable Acres: 1.39 Acres Required Tree Credit Density (1.39 Acres x 30 Credits/Acre): 42.0 Tree Credits Proposed Tree Retention: Developed Area (4 trees) 32.0 Tree Credits Shortfall of Tree Credit Requirement: 10.0 Tree Credits By retaining 4 of the significant trees on the site, this plan falls short of the minimum significant tree retention requirement by 1 tree. Required tree credit retention is less than the minimum tree Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 6 credits by 10.0 credits. Additional trees will be required to be replanted to replace minimum shortfall. When the required number of protected trees cannot be retained, replacement trees, with at least a two-inch (2") caliper deciduous or an evergreen at least six feet (6') tall, shall be planted based on the tree credit value of each protected tree removed. A fee in lieu of tree planting, the cost of which can be determined by the City of Renton can also substitute for tree replacement if replanting on-site is not feasible. All reasonable efforts have been taken to preserve trees utilizing the highest priority possible. The retention of higher priority trees is not feasible or practical for the project site due to the required improvements along Shattuck Avenue. The trees in this area that form a continuous canopy are in poor condition from topping. The location of trees and the lot layout limits the number of trees that can be retained on this project. Recommendations Tree Protection Measures All save trees, including off-site edge trees, must be protected during construction by a temporary chain-link fence (Attachment 7). Placards shall be placed on the fencing every 50 feet indicating the words, "NO TRESPASSING - Protected Trees". The individual tree RPZ is the dripline (6 feet minimum), unless otherwise delineated by WFCI in the field and described in the attached tree list (Attachment 3). If approved, the silt-fence could double as the tree protection fence for select off-site trees. Tree protection fences should be placed around the edge of the root protection zone (RPZ). The fence should be erected after logging but prior to the start of clearing. The fences should be maintained until the start of the landscape installation. There should be no equipment activity (including rototilling) within the root protection zone. No irrigation lines, trenches, or other utilities should be installed within the RPZ. Cuts or fills should impact no more than 20% of a tree’s root system. If topsoil is added to the root zone of a protected tree, the depth should not exceed 2 inches of a sandy loam or loamy fine sand topsoil and should not cover more than 20% of the root system. If roots are encountered outside the RPZ during construction, they should be cut cleanly with a saw and covered immediately with moist soil. Noxious vegetation within the root protection zone should be removed by hand. If a proposed save tree must be impacted by grading or fills more than allowed for by WFCI in the tree list, then the tree should be re-evaluated by WFCI to determine if the tree can be saved with mitigating measures, or if the tree should be removed. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 7 Pruning and Thinning Pruning should be done to coincide with land clearing, to facilitate clean-up and while access to the trees is available (before houses are constructed). All individual trees to be saved near or within developed areas should have their crowns raised to provide a minimum of 8 feet of ground clearance over sidewalks and landscape areas, 15 feet over parking lots or streets, and at least 10 feet of building clearance. Care will need to be taken to avoid trespassing when pruning offsite trees. This is best achieved by getting cooperation and permission from the tree owner. If no permission is obtained, then legally one cannot prune beyond the property line – ground to sky. All pruning should be done according to the ANSI A300 standards for proper pruning and be completed by an International Society of Arboriculture Certified Arborist®, or be supervised by a Certified Arborist®. Conclusions and Timeline for Activity 1. Four significant trees equaling 32.0 tree credits are proposed to be retained on the site. 2. The final, approved tree protection plan map should be included in the construction drawings for bid and construction of the project and should be labeled as such. 3. Stake and heavily flag the clearing limits. 4. Contact WFCI to attend pre-job conference and discuss tree protection issues with contractors. WFCI can verify all trees to be saved and/or removed are adequately marked. 5. Conduct logging. Complete necessary hazard tree removals and invasive plant removals from the tree protection areas. No equipment should enter the tree protection areas during logging. 6. Before land clearing is complete, do all necessary pruning on save trees and off-site trees to provided new home clearances. 7. Contact WFCI to inspect the tree tracts after logging, but prior to land clearing to identify any additional hazard trees that should be removed. 8. Install tree protection fences along the 'limits of construction'. The fences should be located at the limits of construction or at the dripline of the save tree or as otherwise specified by WFCI. Maintain fences throughout construction. 9. Complete clearing of the project. 10. Do not excavate stumps within 10’ of trees to be saved. These should be individually evaluated by WFCI to determine the method of removal. 11. Complete grading and construction of the project. 12. Contact WFCI to final inspect the tree protection areas after grading. 13. All save trees within reach of targets should be inspected annually for 2 years by a qualified professional forester retained by the homeowner’s association, and bi-annually thereafter. The purpose of these inspections is to identify trees that develop problems due to changing micro-site conditions and to prescribe cultural care or removal. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 8 Summary The City of Renton Municipal Code calls for 5 of the healthy, significant trees and 42.0 tree credits to be retained on the site. Based on the current site plan, 4 existing trees equaling 32.0 tree credits will be retained. One additional tree will be required to replace the 30% significant tree requirement shortfall. In addition, ten tree credits will need to be replaced. Please give us a call if you have any questions. Respectfully submitted, Washington Forestry Consultants, Inc. Galen M. Wright, ACF, ASCA Joshua Sharpes ISA Bd. Certified Master Arborist PN-129BU Professional Forester Certified Forester No. 44 ISA Certified Arborist®, ISA Tree Risk Assessor Qualified Municipal Specialist, PN- 5939AM ASCA Tree and Plant Appraisal Qualified ISA Tree Risk Assessor Qualified attachments: 1: aerial photo of project area 2: site plan 3: tree list 4: individual tree rating key 5: description of tree evaluation methodology 6: glossary of terms 7: tree protection fence detail 8: assumptions and limiting conditions Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 9 Attachment 1. Aerial Photo of Talbot Road Project (2019 King County) Project Area Boundary Healthy Tree Unhealthy Tree 1 2 3 4 9 10 11 12 13 14 15 16 17 18 19 20 26 25 24 23 22 21 8 7 6 5 Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 10 Attachment 2. Talbot Road Project Site Plan Project Area Boundary Retained Tree Tree Protection Fence Locations 1 2 3 4 Existing house to remain Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 11 Attachment 3. List of Trees on Talbot Road Project Tree # Species DBH (in.) Calculated DBH (in.) Condition Average Dripline (feet) Landmark Tree Save Based on Condition Alone? Yes or No Minimum Root Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment 1 Cypress 20 20 Good 10 Yes 10 Save 8 2 Cypress 19 19 Good 8 Yes 10 Save 8 3 Holly 17, 18 25 Good 8 X Yes 13 Save 10 4 Holly 7, 8, 10 15 Poor 8 No 8 Save 6 dying top 5 Apple 6, 8 10 Good 10 Yes 5 Remove 5 6 Apple 6 6 Good 7 Yes 3 Remove 4 7 Apple 19 19 Good 13 Yes 10 Remove 8 8 Apple 21 21 Good 15 Yes 11 Remove 8 9 Flowering Dogwood 8 8 Good 10 Yes 6 Remove 4 10 Bigleaf Maple 15 15 Very Poor 19 No 8 Remove 6 5 sprouts off old stump 11 Hawthorn 14 14 Good 12 Yes 7 Remove 6 12 Apple 10 10 Very Poor 10 No 6 Remove 5 dead top, poor tree 13 Hawthorn 14 14 Good 14 Yes 7 Remove 6 14 Cherry 5, 5 7 Good 20 Yes 4 Remove 4 15 Oregon Ash 6, 10 12 Very Poor 20 No 6 Remove 5 dead tops, mostly dead 16 Hawthorn 6 6 Good 15 Yes 6 Remove 4 17 Bigleaf Maple 22 22 Poor 20 No 11 Remove 9 topped multiple times for powerlines 18 Bigleaf Maple 18, 18 25 Poor 20 No 13 Remove 10 topped multiple times for powerlines 19 Apple 20 20 Poor 19 No 10 Remove 8 topped multiple times for powerlines 20 Cherry 6, 7 9 Poor 14 No 6 Remove 4 topped multiple times for powerlines 21 Cherry 6-12 17 Poor 18 No 9 Remove 7 4 stems, topped multiple times for powerlines 22 Oregon Ash 30 30 Poor 23 X No 15 Remove 11 topped multiple times for powerlines 23 Oregon Ash 13, 14 19 Poor 15 No 10 Remove 8 topped multiple times for powerlines 24 Cherry 14 14 Poor 18 No 7 Remove 6 topped multiple times for powerlines 25 Oregon Ash 24 24 Poor 17 X No 12 Remove 9 topped multiple times for powerlines Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 12 Tree # Species DBH (in.) Calculated DBH (in.) Condition Average Dripline (feet) Landmark Tree Save Based on Condition Alone? Yes or No Minimum Root Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment 26 Oregon Ash 22 22 Poor 18 No 11 Remove 9 topped multiple times for powerlines Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 13 Attachment 4. Individual Tree Rating Key for Tree Condition RATING SYMBOL DEFINITION Very Good VG • Balanced crown that is characteristic of the species • Normal lateral and terminal branch growth rates for the species and soil type • Stem sound, normal bark vigor • No root problems • No insect or disease problems • Long-term, attractive tree Good G • Crown lacking symmetry but nearly balanced • Normal lateral and terminal branch growth rates for the species and soil type • Minor twig dieback O.K. • Stem sound, normal bark vigor • No root problems • No or minor insect or disease problems – insignificant • Long-term tree Fair F • Crown lacking symmetry due to branch loss • Slow lateral and terminal branch growth rates for the species and soil type • Minor and major twig dieback – starting to decline • Stem partly unsound, slow diameter growth and low bark vigor • Minor root problems • Minor insect or disease problems • Short-term tree 10-30 years RATING SYMBOL DEFINITION Poor P • Major branch loss – unsymmetrical crown • Greatly reduced growth • Several structurally import dead or branch scaffold branches • Stem has bark loss and significant decay with poor bark vigor • Root damage • Insect or disease problems – remedy required • Short-term tree 1-10 years Very Poor VP • Lacking adequate live crown for survival and growth • Severe decline • Minor and major twig dieback • Stem unsound, bark sloughing, previous stem or large branch failures, very poor bark vigor • Severe root problems or disease • Major insect or disease problems • Mortality expected within the next few years Dead DEAD • Dead Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 14 Cultural Care Needs: ABBRV. ACTIVITY DESCRIPTION CC Crown Cleaning Pruning of dead, dying, diseased, damaged, or defective branches over 1/2 inch in diameter –includes removal of dead tops CT Crown Thinning Pruning of branches described in crown cleaning, plus thinning of up to 20% of the live branches over ½ inch diameter. Branch should be 1/3 to ½ the diameter of the lateral branch. Thinning should be well distributed throughout crown of tree, and should release healthy, long-term branches. RC Crown Reduction Reduction of the crown of a tree by pruning to lateral branches. Generally used to remove declining branches or to lighten end weight on long branches. CR Crown Raising Pruning of lower branches to remove deadwood or to provide ground or building clearances. RMV Remove Remove tree due to decline or hazardous conditions that cannot be mitigated by pruning. RS Remove Sprouts Remove basal sprouts from stem of tree. Rep Replace Tree is small – is in decline or dead. Replace with suitable tree species. HT Hazard Tree Tree is hazardous and cannot be mitigated by pruning. Recommendation is to remove tree. None No Work No work necessary at this time. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 15 Attachment 5. Description of Tree Evaluation Methodology The evaluation of the tree condition on this site included the visual assessment of: 1. Live-crown ratio, 2. Lateral and terminal branch growth rates, 3. Presence of dieback in minor and major scaffold branches and twigs, 4. Foliage color, 5. Stem soundness and other structural defects, 6. Visual root collar examination, 7. Presence of insect or disease problems. 8. Windfirmness if tree removal will expose this tree to failure. In cases where signs of internal defect or disease were suspected, a core sample was taken to look for stain, decay, and diameter growth rates. Also, root collars were exposed to look for the presence of root disease. In all cases, the overall appearance of the tree was considered relative to its ability to add value to either an individual lot or the entire subdivision. Also, the scale of the tree and its proximity to both proposed and existing houses was considered. Lastly, the potential for incorporation into the project design is evaluated, as well as potential site plan modifications that may allow otherwise removed tree(s) to be both saved and protected in the development. Trees that are preserved in a development must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment, and perform well in the landscape. Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be preserved in areas where damage to people or property could occur. Trees that have developed in a forest stand are adapted to the close, dense conditions found in such stands. When surrounding trees are removed during clearing and grading, the remaining trees are exposed to extremes in wind, temperature, solar radiation, which causes sunscald, and other influences. Young, vigorous trees with well-developed crowns are best able to adapt to these changing site conditions. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 16 Attachment 6. Glossary of Forestry and Arboricultural Terminology DBH: Diameter at Breast Height (measured 4.5 ft. above the ground line on the high side of the tree). Live Crown Ratio: Ratio of live foliage on the stem of the tree. Example: A 100’ tall tree with 40 feet of live crown would have a 40% live crown ratio. Conifers with less than 30% live crown ratio are generally not considered to be long-term trees in forestry. Crown: Portion of a trees stem covered by live foliage. Crown Position: Position of the crown with respect to other trees in the stand. Dominant Crown Position: Receives light from above and from the sides. Codominant Crown Position: Receives light from above and some from the sides. Intermediate Crown Position: Receives little light from above and none from the sides. Trees tend to be slender with poor live crown ratios. Suppressed Crown Position: Receives no light from above and none from the sides. Trees tend to be slender with poor live crown ratios. Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 17 Attachment 7. Tree Protection Fence Detail 6 ft. Temporary Chain Link Fence NO TRESPASSING - Protected Trees Talbot Road Project – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 18 Attachment 8. Assumptions and Limiting Conditions 1) Any legal description provided to the Washington Forestry Consultants, Inc. is assumed to be correct. Any titles and ownership's to any property are assumed to be good and marketable. No responsibility is assumed for matters legal in character. Any and all property is appraised or evaluated as though free and clear, under responsible ownership and competent management. 2) It is assumed that any property is not in violation of any applicable codes, ordinances, statutes, or other governmental regulations, unless otherwise stated. 3) Care has been taken to obtain all information from reliable sources. All data has been verified insofar as possible; however, Washington Forestry Consultants, Inc. can neither guarantee nor be responsible for the accuracy of information. 4) Washington Forestry Consultants, Inc. shall not be required to give testimony or to attend court by reason of this report unless subsequent contractual arrangements are made, including payment of an additional fee for such services as described in the fee schedule and contract of engagement. 5) Loss or alteration of any part of this report invalidated the entire report. 6) Possession of this report or a copy thereof does not imply right of publication or use for any purpose by any other than the person to whom it is addressed, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. 7) Neither all or any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, including the client, to the public through advertising, public relations, news, sales or other media, without the prior expressed written or verbal consent of Washington Forestry Consultants, Inc. -- particularly as to value conclusions, identity of Washington Forestr y Consultants, Inc., or any reference to any professional society or to any initialed designation conferred upon Washington Forestry Consultants, Inc. as stated in its qualifications. 8) This report and any values expressed herein represent the opinion of Washington Forestry Consultants, Inc., and the fee is in no way contingent upon the reporting of a specified value, a stipulated result, the occurrence neither of a subsequent event, nor upon any finding in to reported. 9) Sketches, diagrams, graphs, and photographs in this report, being intended as visual aids, are not necessarily to scale and should not be construed as engineering or architectural reports or surveys. 10) Unless expressed otherwise: 1) information contained in this report covers only those items that were examined and reflects the condition of those items at the time of inspection; and 2) the inspection is limited to visual examination of accessible items without dissection, excavation, probing, or coring. There is no warranty or guarantee, expressed or implied, that problems or deficiencies of the tree or other plant or property in question may not arise in the future. Note: Even healthy trees can fail under normal or storm conditions. The only way to eliminate all risk is to remove all trees within reach of all targets. Annual inspections by an ISA Certified Arborist or Certified Forester will reduce the potential of tree failures. It is impossible to predict with certainty that a tree will stand or fail, or the timing of the failure. It is considered an ‘Act of God’ when a tree fails, unless it is directly felled or pushed over by man’s actions. rentonwa.gov/permitcenter | planningcustomerservice@rentonwa.gov | 425-430-7294 10/6/2022 Page 1 of 3 CITY OF RENTON Ι PERMIT CENTER TREE RETENTION AND CREDIT WORKSHEET TREE RETENTION REQUIREMENTS A minimum retention of thirty percent (30%) of all significant trees (as defined in RMC 4-11-200) is required on site. Please complete the form below to verify compliance with minimum tree retention requirements. • Identify total number of trees 6-inch caliper or greater (or alder or cottonwood trees 8-inch caliper or greater) on site: Trees Trees Trees Trees Trees Trees Required Trees Proposed •Deductions – Certain trees are excluded from the retention calculation: o Trees that are high-risk, as defined in RMC 4-11-200: o Trees within existing and proposed public right-of-way: o Trees within wetlands, streams, very high landslide hazards, protected slopes, and associated buffers: •Total remaining trees after deductions: •Required tree retention (30%): •Identify number of trees proposed for retention: •Identify number of trees requested for replacement in lieu of retention (skip page 3 if no tree replacement is requested):Trees TREE CREDIT REQUIREMENTS Tree credit requirements apply at a minimum rate of thirty (30) credits per net acre. Complete the form below to determine minimum tree credit requirements. •Gross area of property in square feet: Square Feet •Deductions: Certain areas are excluded from tree credit calculation: o Existing and proposed public right-of-way: Square Feet o Wetlands, streams, very high landslide hazards, protected slopes, and associated buffers: Square Feet •Total excluded area:Square Feet •Net land area (after deductions) in square feet:Square Feet •Net land area (after deductions) in acres:Acres •Required tree credits:Tree Credits Required 26 0 10 0 16 4.8 4 0.7999999999999998 60548 0 0 0 60548 1.3899908172635445 41.69972451790633 rentonwa.gov/permitcenter | planningcustomerservice@rentonwa.gov | 425-430-7294 10/6/2022 Page 2 of 3 TREE RETENTION AND CREDIT WORKSHEET PROPOSED TREE CREDITS Please complete the table below to calculate the total tree credits proposed for your project. Identify the quantity of trees for each tree category, after deducting trees within excluded areas, as shown in the previous section. TREE SIZE TREE CREDITS TREE QUANTITY TOTAL TREE CREDITS RETAINED TREES Preserved tree 6 – 9” caliper 4 Preserved tree 10 – 12” caliper 5 Preserved tree 12 – 15” caliper 6 Preserved tree 16 – 18” caliper 7 Preserved tree 19 – 21” caliper 8 Preserved tree 22 – 24” caliper 9 Preserved tree 25 – 28” caliper 10 Preserved tree 29 – 32” caliper 11 Preserved tree 33 – 36” caliper 12 Preserved tree 37” caliper and greater 13 NEW TREES New small species tree (30' or less at maturity) 0.25 New medium species tree (30' to 50' at maturity) 1 New large species tree (50' or more at maturity) 2 TREE CREDITS PROPOSED: 1 2 1 32 0 0 6 0 16 0 10 0 0 0 0 0 0 rentonwa.gov/permitcenter | planningcustomerservice@rentonwa.gov | 425-430-7294 10/6/2022 Page 3 of 3 TREE RETENTION AND CREDIT WORKSHEET TREE REPLACEMENT JUSTIFICATION Replacement may be authorized as an alternative to 30% retention provided the removal is the minimum necessary to accomplish the desired purpose and provided the proposal meets one of the following options: a. There are special circumstances related to the size, shape, topography, location, or surroundings of the subject property; or b. The strict application of the code would prevent reasonable use of property; or c. The strict application of the code would prevent compliance with minimum density requirements of the zone; or d. The project is a short plat with four (4) or fewer lots. Please attach a written justification demonstrating compliance with the requirements and criteria as descripted above. TREE REPLACEMENT QUANTITY Tree replacement quantity is determined based on the credit value of the trees proposed for removal. Larger, higher priority trees shall be used for calculation of tree replacement. Identify the quantity of each tree requested to be removed in lieu of 30% retention, based on tree size. List the identification number of each tree, as indicated in the arborist report. TREE SIZE TREE CREDITS TREE QUANTITY TREE INDENTIFICATION # TOTAL TREE CREDITS Tree 37” caliper + 13 Tree 33 – 36” caliper 12 Tree 29 – 32” caliper 11 Tree 25 – 28” caliper 10 Tree 22 – 24” caliper 9 Tree 19 – 21” caliper 8 Tree 16 – 18” caliper 7 Tree 12 – 15” caliper 6 Tree 10 – 12” caliper 5 Tree 6 – 9” caliper 4 REPLACEMENT CREDITS REQUIRED: TREE REPLACEMENT PLANTING Identify the quantity of proposed new replacement trees (minimum size of 2-inch caliper). The total replacement credits proposed should be equal to or greater than the replacement credits required, as shown in the previous section. TREE SIZE TREE CREDITS TREE QUANTITY TOTAL TREE CREDITS New small species tree (30' or less at maturity) 0.25 New medium species tree (30' to 50' at maturity) 1 New large species tree (50' or more at maturity) 2 REPLACEMENT CREDITS PROPOSED: 1 1 3 4 1 4 3 5 146 22 18 17, 25, 26 7, 8, 19, 23 21 10, 11, 13, 24 5, 12, 15 6, 9, 14, 16, 20 0 0 11 10 27 32 7 24 15 20 0 0 0 0 2023 D. R. STRONG Consulting Engineers Inc. Page 44 Mountain View Gardens Technical Information Report Renton, Washington SECTION VII OTHER PERMITS, VARIANCES AND ADJUSTMENTS NPDES Permit from DOE. 2023 D. R. STRONG Consulting Engineers Inc. Page 45 Mountain View Gardens Technical Information Report Renton, Washington SECTION VIII CSWPPP ANALYSIS AND DESIGN (PART A) The Erosion and Sedimentation Control Design will meet the seven minimum King County requirements: 1. Areas to remain undisturbed shall be delineated with a high visibility plastic fence prior to any site clearing or grading. 2. Site disturbed areas shall be covered with mulch and seeded, as appropriate, for temporary or permanent measures. 3. Perimeter protection shall consist of a silt fence down slope of any disturbed areas or stockpiles. 4. A stabilized construction entrance will be located at the point of ingress/egress (i.e. onsite access road). 5. The detention pond will act as a sediment pond for sediment retention. Perimeter silt fences will provide sediment retention within the bypass areas. 6. Surface water from disturbed areas will sheet flow to the sediment pond for treatment. 7. Dust control shall be provided by spraying exposed soils with water until wet. This is required when exposed soils are dry to the point that wind transport is possible which would impact roadways, drainage ways, surface waters, or neighboring residences. SWPPP PLAN DESIGN (PART B) Construction activities that could contribute pollutants to surface and storm water include the following, with applicable BMP’s listed for each item: 1. Storage and use of chemicals: Utilize source control, and soil erosion and sedimentation control practices, such as using only recommended amounts of chemical materials applied in the proper manner; neutralizing concrete wash water, and disposing of excess concrete material only in areas prepared for concrete placement, or return to batch plant; disposing of wash-up waters from water-based paints in sanitary sewer; disposing of wastes from oil-based paints, solvents, thinners, and mineral spirits only through a licensed waste management firm, or treatment, storage, and disposal (TSD) facility. 2. Material delivery and storage: Locate temporary storage areas away from vehicular traffic, near the construction entrance, and away from storm drains. Material Safety Data Sheets (MSDS) should be supplied for all materials stored, and chemicals kept in their original labeled containers. Maintenance, fueling, and repair of heavy equipment and vehicles shall be conducted using spill prevention and control measures. Contaminated surfaces shall be cleaned immediately following any spill incident. Provide cover, containment, and protection from vandalism for all chemicals, liquid products, petroleum products, and other potentially hazardous materials. 2023 D. R. STRONG Consulting Engineers Inc. Page 46 Mountain View Gardens Technical Information Report Renton, Washington 3. Building demolition: Protect stormwater drainage system from sediment-laden runoff and loose particles. To the extent possible, use dikes, berms, or other methods to protect overland discharge paths from runoff. Street gutter, sidewalks, driveways, and other paved surfaces in the immediate area of demolition must be swept daily to collect and properly dispose of loose debris and garbage. Spray the minimum amount of water to help control windblown fine particles such as concrete, dust, and paint chips. Avoid excessive spraying so that runoff from the site does not occur, yet dust control is achieved. Oils must never be used for dust control. 4. Sawcutting: Slurry and cuttings shall be vacuumed during the activity to prevent migration offsite and must not remain on permanent concrete or asphalt paving overnight. Collected slurry and cuttings shall be disposed of in a manner that does not violate ground water or surface water quality standards. A stand alone CSWPPP will be provided at the time of final engineering. 2023 D. R. STRONG Consulting Engineers Inc. Page 47 Mountain View Gardens Technical Information Report Renton, Washington SECTION IX BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 1. Bond Quantity Worksheet – is located in Appendix C 2. The Stormwater Facility Summary Sheet is included in this section 2023 D. R. STRONG Consulting Engineers Inc. Page 48 Mountain View Gardens Technical Information Report Renton, Washington STORMWATER FACILITY SUMMARY SHEET Development Mountain View Gardens Date July 26, 2023 Location: 2103 Talbot Road S, Renton, Washington ENGINEER DEVELOPER Name Jonathan S. Murray, P.E. Name Lili Lu Firm D.R. STRONG Consulting Engineers, Inc. Firm Seattle LLC LLC Address 620 7th Avenue Address 325 118th Ave SE, Suite 100 Kirkland, WA 98033 Bellevue, WA 98005 Phone (425) 827-3063 Phone (206) 228-4158 Developed Site : 1.568 acres Number of lots: 6 Number of detention facilities on site: Number of infiltration facilities on site: ___1__ vaults ______ vaults ______ pond ______ ponds ______ tanks ______ tanks Flow control provided in regional facility (give location)___________________________ No flow control required_____ Exemption number ______________________________ Downstream Drainage Basins Immediate Major Basin Basin Black River Green/Duwamish River Watershed Number & type of water quality facilities on site: biofiltration swale (regular/wet/ or continuous inflow?) ______ sand filter (basic or large?) ______ sand filter, linear (basic or large?) ______ CONTECH Stormfilter __1___ combined detention/WQ vault ______ sand filter vault (basic or large?) ______ combined detention/wetpond ______ stormwater wetland ______ compost filter ______ wetvault (basic or large?) ______ filter strip ______ Wetvault ______ flow dispersion ______ pre-settling pond ______ farm management plan ______ flow-splitter catchbasin ______ landscape management plan ______ oil/water separator (baffle or coalescing plate?) ______ catch basin inserts: Manufacturer_____________________________________ ______ pre-settling structure: Manufacturer___________________________________ 2023 D. R. STRONG Consulting Engineers Inc. Page 49 Mountain View Gardens Technical Information Report Renton, Washington DESIGN INFORMATION INDIVIDUAL BASIN Water Quality design flow Water Quality treated volume Drainage basin(s) 1 Onsite area (includes frontage) 1.568 Offsite area 0.150 Type of Storage Facility Detention Vault Live Storage Volume (required) 19,440 Predev Runoff Rate 2-year 0.063 10-year 0.132 100-year 0.248 Developed Runoff Rate 2-year 0.044 (includes bypass) 10-year 0.079 100-year 0.145 Type of Restrictor FROP Tee Size of orifice/restriction No. 1 0.781” Ø 0.00’ No. 2 1.000” Ø 3.60’ No. 3 1.125” Ø 4.95’ 2023 D. R. STRONG Consulting Engineers Inc. Page 50 Mountain View Gardens Technical Information Report Renton, Washington SECTION X OPERATIONS AND MAINTENANCE MANUAL To be provided at time of final engineering. 2023 D. R. STRONG Consulting Engineers Inc. Page 51 Mountain View Gardens Technical Information Report Renton, Washington APPENDICES 2023 D. R. STRONG Consulting Engineers Inc. Page 52 Mountain View Gardens Technical Information Report Renton, Washington APPENDIX “A” LEGAL DESCRIPTION TRACT 31, PLAT 2, RENTON CO-OPERATIVE COAL COMPANY ACRE TRACTS, ACCORDING TO THE PLAT THEREOF RECORDED IN VOLUME 9 OF PLATS, PAGE 27, RECORDS OF KING COUNTY, WASHINGTON. SITUATE IN THE COUNTY OF KING, STATE OF WASHINGTON. 2023 D. R. STRONG Consulting Engineers Inc. Page 53 Mountain View Gardens Technical Information Report Renton, Washington APPENDIX “B” WWHM REPORT WWHM2012 PROJECT REPORT 22052 7/6/2023 3:32:40 PM Page 2 General Model Information WWHM2012 Project Name:22052 Site Name:Talbot Site Address:2103 TALBOT RD S City:Renton Report Date:7/6/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year 22052 7/6/2023 3:32:40 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 1.568 C, Lawn, Mod 0.118 Pervious Total 1.686 Impervious Land Use acre ROADS MOD 0.031 Impervious Total 0.031 Basin Total 1.717 22052 7/6/2023 3:32:40 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.723 Pervious Total 0.723 Impervious Land Use acre ROADS FLAT 0.088 ROADS MOD 0.495 ROOF TOPS FLAT 0.357 Impervious Total 0.94 Basin Total 1.663 22052 7/6/2023 3:32:40 PM Page 5 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.008 Pervious Total 0.008 Impervious Land Use acre ROADS FLAT 0.046 Impervious Total 0.046 Basin Total 0.054 22052 7/6/2023 3:32:40 PM Page 6 Routing Elements Predeveloped Routing 22052 7/6/2023 3:32:40 PM Page 7 Mitigated Routing Vault 1 Width:60 ft. Length:54 ft. Depth:7 ft. Discharge Structure Riser Height:6 ft. Riser Diameter:18 in. Orifice 1 Diameter:0.781 in.Elevation:0 ft. Orifice 2 Diameter:1.000 in.Elevation:3.6 ft. Orifice 3 Diameter:1.125 in.Elevation:4.95 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.074 0.000 0.000 0.000 0.0778 0.074 0.005 0.004 0.000 0.1556 0.074 0.011 0.006 0.000 0.2333 0.074 0.017 0.008 0.000 0.3111 0.074 0.023 0.009 0.000 0.3889 0.074 0.028 0.010 0.000 0.4667 0.074 0.034 0.011 0.000 0.5444 0.074 0.040 0.012 0.000 0.6222 0.074 0.046 0.013 0.000 0.7000 0.074 0.052 0.013 0.000 0.7778 0.074 0.057 0.014 0.000 0.8556 0.074 0.063 0.015 0.000 0.9333 0.074 0.069 0.016 0.000 1.0111 0.074 0.075 0.016 0.000 1.0889 0.074 0.081 0.017 0.000 1.1667 0.074 0.086 0.017 0.000 1.2444 0.074 0.092 0.018 0.000 1.3222 0.074 0.098 0.019 0.000 1.4000 0.074 0.104 0.019 0.000 1.4778 0.074 0.109 0.020 0.000 1.5556 0.074 0.115 0.020 0.000 1.6333 0.074 0.121 0.021 0.000 1.7111 0.074 0.127 0.021 0.000 1.7889 0.074 0.133 0.022 0.000 1.8667 0.074 0.138 0.022 0.000 1.9444 0.074 0.144 0.023 0.000 2.0222 0.074 0.150 0.023 0.000 2.1000 0.074 0.156 0.024 0.000 2.1778 0.074 0.162 0.024 0.000 2.2556 0.074 0.167 0.024 0.000 2.3333 0.074 0.173 0.025 0.000 2.4111 0.074 0.179 0.025 0.000 2.4889 0.074 0.185 0.026 0.000 2.5667 0.074 0.190 0.026 0.000 2.6444 0.074 0.196 0.026 0.000 2.7222 0.074 0.202 0.027 0.000 2.8000 0.074 0.208 0.027 0.000 2.8778 0.074 0.214 0.028 0.000 22052 7/6/2023 3:32:40 PM Page 8 2.9556 0.074 0.219 0.028 0.000 3.0333 0.074 0.225 0.028 0.000 3.1111 0.074 0.231 0.029 0.000 3.1889 0.074 0.237 0.029 0.000 3.2667 0.074 0.243 0.029 0.000 3.3444 0.074 0.248 0.030 0.000 3.4222 0.074 0.254 0.030 0.000 3.5000 0.074 0.260 0.031 0.000 3.5778 0.074 0.266 0.031 0.000 3.6556 0.074 0.271 0.038 0.000 3.7333 0.074 0.277 0.041 0.000 3.8111 0.074 0.283 0.044 0.000 3.8889 0.074 0.289 0.047 0.000 3.9667 0.074 0.295 0.049 0.000 4.0444 0.074 0.300 0.051 0.000 4.1222 0.074 0.306 0.053 0.000 4.2000 0.074 0.312 0.055 0.000 4.2778 0.074 0.318 0.056 0.000 4.3556 0.074 0.324 0.058 0.000 4.4333 0.074 0.329 0.059 0.000 4.5111 0.074 0.335 0.061 0.000 4.5889 0.074 0.341 0.062 0.000 4.6667 0.074 0.347 0.063 0.000 4.7444 0.074 0.352 0.065 0.000 4.8222 0.074 0.358 0.066 0.000 4.9000 0.074 0.364 0.067 0.000 4.9778 0.074 0.370 0.074 0.000 5.0556 0.074 0.376 0.081 0.000 5.1333 0.074 0.381 0.085 0.000 5.2111 0.074 0.387 0.089 0.000 5.2889 0.074 0.393 0.093 0.000 5.3667 0.074 0.399 0.096 0.000 5.4444 0.074 0.405 0.099 0.000 5.5222 0.074 0.410 0.102 0.000 5.6000 0.074 0.416 0.105 0.000 5.6778 0.074 0.422 0.107 0.000 5.7556 0.074 0.428 0.110 0.000 5.8333 0.074 0.433 0.112 0.000 5.9111 0.074 0.439 0.115 0.000 5.9889 0.074 0.445 0.117 0.000 6.0667 0.074 0.451 0.393 0.000 6.1444 0.074 0.457 0.990 0.000 6.2222 0.074 0.462 1.760 0.000 6.3000 0.074 0.468 2.627 0.000 6.3778 0.074 0.474 3.514 0.000 6.4556 0.074 0.480 4.346 0.000 6.5333 0.074 0.486 5.056 0.000 6.6111 0.074 0.491 5.602 0.000 6.6889 0.074 0.497 5.984 0.000 6.7667 0.074 0.503 6.342 0.000 6.8444 0.074 0.509 6.651 0.000 6.9222 0.074 0.514 6.946 0.000 7.0000 0.074 0.520 7.229 0.000 7.0778 0.074 0.526 7.501 0.000 7.1556 0.000 0.000 7.764 0.000 22052 7/6/2023 3:32:40 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.686 Total Impervious Area:0.031 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.731 Total Impervious Area:0.986 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.062804 5 year 0.101993 10 year 0.132127 25 year 0.174847 50 year 0.210007 100 year 0.248015 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.043658 5 year 0.06318 10 year 0.078847 25 year 0.102111 50 year 0.122197 100 year 0.144855 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.093 0.041 1950 0.100 0.042 1951 0.118 0.102 1952 0.043 0.030 1953 0.033 0.034 1954 0.047 0.033 1955 0.075 0.037 1956 0.068 0.053 1957 0.068 0.041 1958 0.054 0.036 22052 7/6/2023 3:33:11 PM Page 10 1959 0.047 0.034 1960 0.095 0.076 1961 0.049 0.046 1962 0.031 0.028 1963 0.049 0.036 1964 0.067 0.037 1965 0.054 0.048 1966 0.040 0.033 1967 0.110 0.043 1968 0.064 0.039 1969 0.058 0.036 1970 0.050 0.035 1971 0.061 0.042 1972 0.094 0.067 1973 0.042 0.043 1974 0.062 0.039 1975 0.081 0.043 1976 0.059 0.036 1977 0.023 0.034 1978 0.046 0.040 1979 0.025 0.034 1980 0.141 0.071 1981 0.041 0.038 1982 0.100 0.078 1983 0.065 0.037 1984 0.040 0.031 1985 0.022 0.035 1986 0.094 0.052 1987 0.090 0.070 1988 0.035 0.032 1989 0.027 0.032 1990 0.240 0.086 1991 0.140 0.073 1992 0.055 0.037 1993 0.044 0.029 1994 0.021 0.027 1995 0.060 0.039 1996 0.156 0.103 1997 0.109 0.099 1998 0.045 0.037 1999 0.156 0.067 2000 0.050 0.035 2001 0.020 0.037 2002 0.062 0.055 2003 0.096 0.038 2004 0.091 0.098 2005 0.068 0.038 2006 0.071 0.039 2007 0.194 0.189 2008 0.201 0.105 2009 0.102 0.055 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.2397 0.1895 2 0.2007 0.1047 3 0.1936 0.1030 22052 7/6/2023 3:33:11 PM Page 11 4 0.1559 0.1015 5 0.1555 0.0988 6 0.1412 0.0982 7 0.1401 0.0862 8 0.1183 0.0783 9 0.1101 0.0760 10 0.1087 0.0733 11 0.1019 0.0708 12 0.1002 0.0702 13 0.0996 0.0667 14 0.0958 0.0666 15 0.0951 0.0549 16 0.0942 0.0546 17 0.0939 0.0527 18 0.0930 0.0522 19 0.0910 0.0478 20 0.0904 0.0455 21 0.0807 0.0433 22 0.0753 0.0432 23 0.0706 0.0425 24 0.0679 0.0423 25 0.0679 0.0418 26 0.0678 0.0413 27 0.0673 0.0411 28 0.0653 0.0395 29 0.0643 0.0395 30 0.0622 0.0394 31 0.0616 0.0392 32 0.0607 0.0385 33 0.0598 0.0384 34 0.0590 0.0383 35 0.0577 0.0382 36 0.0551 0.0373 37 0.0545 0.0368 38 0.0542 0.0367 39 0.0500 0.0366 40 0.0499 0.0366 41 0.0490 0.0366 42 0.0488 0.0365 43 0.0470 0.0359 44 0.0468 0.0356 45 0.0455 0.0355 46 0.0452 0.0354 47 0.0441 0.0350 48 0.0430 0.0348 49 0.0418 0.0343 50 0.0409 0.0341 51 0.0401 0.0338 52 0.0398 0.0336 53 0.0351 0.0332 54 0.0329 0.0328 55 0.0307 0.0321 56 0.0271 0.0318 57 0.0246 0.0314 58 0.0235 0.0297 59 0.0222 0.0289 60 0.0212 0.0282 61 0.0199 0.0268 22052 7/6/2023 3:33:11 PM Page 12 22052 7/6/2023 3:33:11 PM Page 13 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0314 12093 9075 75 Pass 0.0332 10534 7048 66 Pass 0.0350 9244 6211 67 Pass 0.0368 8181 5636 68 Pass 0.0386 7208 5304 73 Pass 0.0404 6380 4941 77 Pass 0.0422 5683 4601 80 Pass 0.0440 5084 4295 84 Pass 0.0458 4579 3963 86 Pass 0.0476 4102 3630 88 Pass 0.0494 3666 3364 91 Pass 0.0512 3315 3091 93 Pass 0.0531 2994 2821 94 Pass 0.0549 2697 2586 95 Pass 0.0567 2423 2348 96 Pass 0.0585 2171 2056 94 Pass 0.0603 1957 1804 92 Pass 0.0621 1755 1577 89 Pass 0.0639 1578 1331 84 Pass 0.0657 1394 1127 80 Pass 0.0675 1243 921 74 Pass 0.0693 1125 751 66 Pass 0.0711 1020 673 65 Pass 0.0729 932 638 68 Pass 0.0747 864 586 67 Pass 0.0765 786 543 69 Pass 0.0783 716 504 70 Pass 0.0801 647 472 72 Pass 0.0819 574 448 78 Pass 0.0837 512 400 78 Pass 0.0855 443 378 85 Pass 0.0873 389 352 90 Pass 0.0891 344 329 95 Pass 0.0909 299 297 99 Pass 0.0927 266 255 95 Pass 0.0945 230 213 92 Pass 0.0963 194 182 93 Pass 0.0982 167 142 85 Pass 0.1000 145 121 83 Pass 0.1018 126 104 82 Pass 0.1036 112 79 70 Pass 0.1054 100 68 68 Pass 0.1072 85 63 74 Pass 0.1090 68 58 85 Pass 0.1108 60 51 85 Pass 0.1126 48 45 93 Pass 0.1144 39 43 110 Pass 0.1162 37 39 105 Pass 0.1180 30 30 100 Pass 0.1198 27 21 77 Pass 0.1216 24 18 75 Pass 0.1234 22 17 77 Pass 0.1252 19 15 78 Pass 22052 7/6/2023 3:33:11 PM Page 14 0.1270 18 9 50 Pass 0.1288 17 9 52 Pass 0.1306 16 8 50 Pass 0.1324 15 8 53 Pass 0.1342 14 8 57 Pass 0.1360 12 7 58 Pass 0.1378 10 5 50 Pass 0.1396 10 5 50 Pass 0.1415 8 5 62 Pass 0.1433 8 5 62 Pass 0.1451 8 5 62 Pass 0.1469 8 5 62 Pass 0.1487 8 5 62 Pass 0.1505 8 5 62 Pass 0.1523 8 5 62 Pass 0.1541 8 5 62 Pass 0.1559 7 5 71 Pass 0.1577 5 4 80 Pass 0.1595 5 3 60 Pass 0.1613 5 3 60 Pass 0.1631 5 3 60 Pass 0.1649 5 3 60 Pass 0.1667 5 3 60 Pass 0.1685 5 3 60 Pass 0.1703 5 3 60 Pass 0.1721 5 3 60 Pass 0.1739 5 3 60 Pass 0.1757 5 3 60 Pass 0.1775 5 3 60 Pass 0.1793 5 2 40 Pass 0.1811 5 2 40 Pass 0.1829 4 2 50 Pass 0.1847 4 2 50 Pass 0.1866 4 1 25 Pass 0.1884 4 1 25 Pass 0.1902 4 0 0 Pass 0.1920 4 0 0 Pass 0.1938 3 0 0 Pass 0.1956 3 0 0 Pass 0.1974 3 0 0 Pass 0.1992 3 0 0 Pass 0.2010 2 0 0 Pass 0.2028 2 0 0 Pass 0.2046 1 0 0 Pass 0.2064 1 0 0 Pass 0.2082 1 0 0 Pass 0.2100 1 0 0 Pass 22052 7/6/2023 3:33:11 PM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.1368 acre-feet On-line facility target flow:0.1572 cfs. Adjusted for 15 min:0.1572 cfs. Off-line facility target flow:0.0874 cfs. Adjusted for 15 min:0.0874 cfs. 22052 7/6/2023 3:33:11 PM Page 16 LID Report 22052 7/6/2023 3:33:33 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. 22052 7/6/2023 3:33:33 PM Page 18 Appendix Predeveloped Schematic 22052 7/6/2023 3:33:34 PM Page 19 Mitigated Schematic 22052 7/6/2023 3:33:35 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 22052.wdm MESSU 25 Pre22052.MES 27 Pre22052.L61 28 Pre22052.L62 30 POC220521.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 11 PERLND 17 IMPLND 2 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 *** 11 C, Forest, Mod 1 1 1 1 27 0 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 11 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR 22052 7/6/2023 3:33:35 PM Page 21 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 11 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 11 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 11 0 4.5 0.08 400 0.1 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 11 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 11 0.2 0.5 0.35 6 0.5 0.7 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 11 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 2 ROADS/MOD 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 2 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 2 0 0 4 0 0 4 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 2 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 22052 7/6/2023 3:33:35 PM Page 22 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 2 400 0.05 0.1 0.08 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 2 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 2 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 11 1.568 COPY 501 12 PERLND 11 1.568 COPY 501 13 PERLND 17 0.118 COPY 501 12 PERLND 17 0.118 COPY 501 13 IMPLND 2 0.031 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 *** 22052 7/6/2023 3:33:35 PM Page 23 <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN 22052 7/6/2023 3:33:35 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 22052.wdm MESSU 25 Mit22052.MES 27 Mit22052.L61 28 Mit22052.L62 30 POC220521.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 2 IMPLND 4 PERLND 17 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 17 C, Lawn, Mod 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 22052 7/6/2023 3:33:35 PM Page 25 16 0 0 1 0 0 0 0 0 0 0 0 0 17 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 17 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 17 0 4.5 0.03 400 0.1 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 17 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 17 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 17 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 2 ROADS/MOD 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 2 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 ********* 22052 7/6/2023 3:33:35 PM Page 26 1 0 0 4 0 0 4 1 9 2 0 0 4 0 0 0 1 9 4 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 2 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 2 400 0.05 0.1 0.08 4 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 2 0 0 4 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 2 0 0 4 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 0.723 RCHRES 1 2 PERLND 16 0.723 RCHRES 1 3 IMPLND 1 0.088 RCHRES 1 5 IMPLND 2 0.495 RCHRES 1 5 IMPLND 4 0.357 RCHRES 1 5 Bypass*** PERLND 17 0.008 COPY 501 12 PERLND 17 0.008 COPY 601 12 PERLND 17 0.008 COPY 501 13 PERLND 17 0.008 COPY 601 13 IMPLND 1 0.046 COPY 501 15 IMPLND 1 0.046 COPY 601 15 ******Routing****** PERLND 16 0.723 COPY 1 12 IMPLND 1 0.088 COPY 1 15 IMPLND 2 0.495 COPY 1 15 IMPLND 4 0.357 COPY 1 15 PERLND 16 0.723 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 22052 7/6/2023 3:33:35 PM Page 27 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Vault 1 1 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 0 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.01 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 92 4 Depth Area Volume Outflow1 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (ft/sec) (Minutes)*** 0.000000 0.074380 0.000000 0.000000 0.077778 0.074380 0.005785 0.004620 0.155556 0.074380 0.011570 0.006533 0.233333 0.074380 0.017355 0.008002 0.311111 0.074380 0.023140 0.009240 0.388889 0.074380 0.028926 0.010330 0.466667 0.074380 0.034711 0.011316 0.544444 0.074380 0.040496 0.012223 0.622222 0.074380 0.046281 0.013067 0.700000 0.074380 0.052066 0.013859 0.777778 0.074380 0.057851 0.014609 0.855556 0.074380 0.063636 0.015322 0.933333 0.074380 0.069421 0.016003 1.011111 0.074380 0.075207 0.016657 22052 7/6/2023 3:33:35 PM Page 28 1.088889 0.074380 0.080992 0.017286 1.166667 0.074380 0.086777 0.017892 1.244444 0.074380 0.092562 0.018479 1.322222 0.074380 0.098347 0.019048 1.400000 0.074380 0.104132 0.019600 1.477778 0.074380 0.109917 0.020137 1.555556 0.074380 0.115702 0.020660 1.633333 0.074380 0.121488 0.021171 1.711111 0.074380 0.127273 0.021669 1.788889 0.074380 0.133058 0.022156 1.866667 0.074380 0.138843 0.022632 1.944444 0.074380 0.144628 0.023099 2.022222 0.074380 0.150413 0.023556 2.100000 0.074380 0.156198 0.024005 2.177778 0.074380 0.161983 0.024446 2.255556 0.074380 0.167769 0.024878 2.333333 0.074380 0.173554 0.025304 2.411111 0.074380 0.179339 0.025722 2.488889 0.074380 0.185124 0.026133 2.566667 0.074380 0.190909 0.026539 2.644444 0.074380 0.196694 0.026938 2.722222 0.074380 0.202479 0.027331 2.800000 0.074380 0.208264 0.027719 2.877778 0.074380 0.214050 0.028101 2.955556 0.074380 0.219835 0.028478 3.033333 0.074380 0.225620 0.028851 3.111111 0.074380 0.231405 0.029218 3.188889 0.074380 0.237190 0.029581 3.266667 0.074380 0.242975 0.029940 3.344444 0.074380 0.248760 0.030294 3.422222 0.074380 0.254545 0.030644 3.500000 0.074380 0.260331 0.030990 3.577778 0.074380 0.266116 0.031333 3.655556 0.074380 0.271901 0.038068 3.733333 0.074380 0.277686 0.041916 3.811111 0.074380 0.283471 0.044807 3.888889 0.074380 0.289256 0.047252 3.966667 0.074380 0.295041 0.049424 4.044444 0.074380 0.300826 0.051405 4.122222 0.074380 0.306612 0.053243 4.200000 0.074380 0.312397 0.054968 4.277778 0.074380 0.318182 0.056602 4.355556 0.074380 0.323967 0.058159 4.433333 0.074380 0.329752 0.059651 4.511111 0.074380 0.335537 0.061086 4.588889 0.074380 0.341322 0.062471 4.666667 0.074380 0.347107 0.063812 4.744444 0.074380 0.352893 0.065112 4.822222 0.074380 0.358678 0.066377 4.900000 0.074380 0.364463 0.067609 4.977778 0.074380 0.370248 0.074535 5.055556 0.074380 0.376033 0.081144 5.133333 0.074380 0.381818 0.085840 5.211111 0.074380 0.387603 0.089809 5.288889 0.074380 0.393388 0.093356 5.366667 0.074380 0.399174 0.096614 5.444444 0.074380 0.404959 0.099657 5.522222 0.074380 0.410744 0.102531 5.600000 0.074380 0.416529 0.105267 5.677778 0.074380 0.422314 0.107888 5.755556 0.074380 0.428099 0.110408 5.833333 0.074380 0.433884 0.112842 5.911111 0.074380 0.439669 0.115199 5.988889 0.074380 0.445455 0.117488 6.066667 0.074380 0.451240 0.393410 6.144444 0.074380 0.457025 0.990875 6.222222 0.074380 0.462810 1.760948 6.300000 0.074380 0.468595 2.627335 6.377778 0.074380 0.474380 3.514384 6.455556 0.074380 0.480165 4.346178 22052 7/6/2023 3:33:35 PM Page 29 6.533333 0.074380 0.485950 5.056232 6.611111 0.074380 0.491736 5.602289 6.688889 0.074380 0.497521 5.984620 6.766667 0.074380 0.503306 6.342723 6.844444 0.074380 0.509091 6.651687 6.922222 0.074380 0.514876 6.946775 7.000000 0.074380 0.520661 7.229707 7.077778 0.074380 0.526446 7.501876 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** 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 22052 7/6/2023 3:33:35 PM Page 30 Predeveloped HSPF Message File 22052 7/6/2023 3:33:35 PM Page 31 Mitigated HSPF Message File 22052 7/6/2023 3:33:35 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 2023 D. R. STRONG Consulting Engineers Inc. Page 54 Mountain View Gardens Technical Information Report Renton, Washington APPENDIX “C” CSWPPP 2023 D. R. STRONG Consulting Engineers Inc. Page 55 Mountain View Gardens Technical Information Report Renton, Washington APPENDIX “D” BOND QUANTITY WORKSHEET