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Home My WebLink AboutRS_TIR_251112_v1 Western Washington Division Eastern Washington Division 165 NE Juniper St., Ste 201, Issaquah, WA 98027 407 Swiftwater Blvd, Cle Elum, WA 98922 Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419 www.EncompassES.net PRELIMINARY TECHNICAL INFORMATION REPORT For Lincoln Peak Short Plat 3601 Lincoln Ave NE Renton, WA 98056 November 12th, 2025 Prepared by: Gabe Garner Encompass Engineering Job No. 25560 Prepared For: Geoff Sherwin JK Monarch LLC PO Box 188 Puyallup, WA 98371 Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | i Table of Contents List of Figures ................................................................................................................................... i I. PROJECT OVERVIEW ................................................................................................................ 1 II. CONDITIONS AND REQUIREMENTS SUMMARY ...................................................................... 7 III. DOWNSTREAM ANALYSIS ...................................................................................................... 12 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................... 17 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ..................................................................... 20 VII. OTHER PERMITS ..................................................................................................................... 20 VIII. CSWPP ANALYSIS AND DESIGN .............................................................................................. 20 IX. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION of COVENANT .................. 20 X. OPERATION AND MAINTENANCE MANUAL .......................................................................... 20 List of Figures Figure 1 – TIR Worksheet Figure 2 – Vicinity Map Figure 3 – Soils Map and Legend Figure 4 – Existing Conditions Map Figure 5 – Developed Conditions Map Figure 6 – Drainage Review Flow Chart Figure 7 – Downstream Map Appendix A Geotechnical Report by Terra Associates, Inc. dated July 23, 2025 Appendix B Wetland and Stream Reconnaissance by Wetland Resources, Inc. dated April 15, 2025 Appendix C Preliminary Tree Protection Plan by Washington Forestry Consultants, Inc. dated May 28, 2025 Appendix D WWHM Output CITY OF RENTON SURFACE WATER DESIGN MANUAL 2022 City of Renton Surface Water Design Manual 6/22/2022 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Land Use (e.g., Subdivision / Short Subd.)  Building (e.g., M/F / Commercial / SFR)  Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified __________________ __________________ __________________ REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 9 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ On-site BMPs Describe: Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2022 City of Renton Surface Water Design Manual 6/22/2022 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Control Pollutants  Protect Existing and Proposed BMPs/Facilities  Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary  Flag limits of sensitive areas and open space preservation areas  Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Description Water Quality Description On-site BMPs Description  Detention  Infiltration  Regional Facility  Shared Facility  Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________  Full Dispersion  Full Infiltration  Limited Infiltration  Rain Gardens  Bioretention  Permeable Pavement  Basic Dispersion  Soil Amendment  Perforated Pipe Connection  Other _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ _____________ REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 6/22/2022 2022 City of Renton Surface Water Design Manual 8-A-6 Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ____________________________  Cast in Place Vault  Retaining Wall  Rockery > 4′ High  Structural on Steep Slope  Other _______________________________ Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 1 I. PROJECT OVERVIEW Project: Lincoln Peak Short Plat Site Address: 3601 Lincoln Ave NE, Renton, WA 98056 (See Vicinity Map) Tax Parcel: 334570-0230 Zoning District: R-8 Site Area: 48,066 SF (1.10 AC) – as surveyed Site Location: The site is in the City of Renton within the NE quarter of Section 32, Township 24 North, Range 5 East, W.M, King County, Washington. The site is located on the west side of Lincoln Ave NE, at the intersection of Lincoln Ave NE & NE 36th St. Figure 2: Vicinity Map Pre-developed Site Conditions: The project site is located in the City of Renton on a 48,066 SF (1.10 AC) lot that is zoned as R-8. The property may currently be accessed via Lincoln Ave NE in the eastern portion of the site. The site is bordered to the north and west by single-family residential properties, to the south by an undeveloped section of public right-of-way (ROW), and to the east by Lincoln Ave NE. The site is currently developed with a single-family residence, detached garage, gravel driveway, and concrete driveway. Stormwater runoff produced from the existing site sheet flows towards the natural discharge area (NDA) located in the western portion of the site. The eastern portion of the site contains moderate slopes ranging from 2-15%, and the western portion of the site contains steep slopes of up to 75%. The property is located within the May Creek drainage basin, within the Cedar River/Lake Washington watershed. See the full downstream analysis in Section III of this Technical Information Report (TIR) for more information. An Existing Conditions Map is included as Figure 4 at the end of this Section. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 2 Critical Areas: According to King County iMap, City of Renton GIS Map, the Geotechnical Report by Terra Associates, Inc. (Appendix A), and the Wetland and Stream Reconnaissance by Wetland Resources, Inc. (Appendix B), the western portion of the site is located within an erosion hazard area as well as a landslide hazard area. Additionally, there is a Category III wetland located approximately 100 feet south of the site, which must honor an additional 15-foot building setback from the wetland buffer. Soils: Per the US Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS) information, the project site is underlain with Alderwood gravelly sandy loam & Alderwood and Kitsap soils (See Figure 3 below). The Geotechnical Report prepared by Terra Associates, Inc. (Appendix A) states that stormwater management at the site should not be managed with infiltration facilities, as the soils underling the site largely consist of silty sand which exhibit low permeabilities and would impede the downward migration of stormwater. Figure 3: Soil Map and Legend Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 3 Developed Site Conditions The project proposes the development of five (5) single-family lots within the 48,066 SF (1.10 AC) parcel. Lot 1 is 7,333 SF and will be located in the northeastern portion of the site, Lot 2 is 7,690 SF and will be located in the northwestern portion of the site, Lot 3 is 6,036 SF and will be located in the southeastern portion of the site, Lot 4 is 6,095 SF and will be located directly west of Lot 3, and Lot 5 is 7,552 SF and will be located in the southwestern portion of the site. A 1,770 SF private access tract (Tract A) is proposed between Lots 4 and 5 and will provide access to Lots 2 and 5 via NE 36th Street in the southern portion the site, a 4,358 SF critical area tract (Tract B) will be located along the western edge of the site, and a 7,233 SF ROW dedication is proposed along the southern and eastern property boundaries. The proposed impervious surfaces associated with this short plat include a 1,770 SF asphalt access road, 462 SF of concrete driveway aprons, 4,803 SF of asphalt pavement widening, 1,648 SF of concrete sidewalk, and a 217 SF concrete ADA ramp (for a total of 8,900 SF of impervious surfaces). The parcel is zoned R-8, which allows for a maximum building coverage of 50% and a maximum impervious surface coverage of 65%. For the preliminary design of the lots, the maximum impervious surface coverage was assumed: • Lot 1: The maximum allowable impervious surface coverage for Lot 1 is 7,333 SF * 0.65 = 4,766 SF. The final site layout of Lot 1 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 1 will use the maximum coverage stated above (4,766 SF). • Lot 2: The maximum allowable impervious surface coverage for Lot 2 is 7,690 SF * 0.65 = 4,998 SF. The final site layout of Lot 2 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 2 will use the maximum coverage stated above (4,998 SF). • Lot 3: The maximum allowable impervious surface coverage for Lot 3 is 6,036 SF * 0.65 = 3,923 SF. The final site layout of Lot 3 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 3 will use the maximum coverage stated above (3,923 SF). • Lot 4: The maximum allowable impervious surface coverage for Lot 4 is 6,095 SF * 0.65 = 3,962 SF. The final site layout of Lot 4 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 4 will use the maximum coverage stated above (3,962 SF). • Lot 5: The maximum allowable impervious surface coverage for Lot 5 is 7,552 SF * 0.65 = 4,908 SF. The final site layout of Lot 5 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 5 will use the maximum coverage stated above (4,908 SF). Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 4 The total impervious surface area associated with the individual lots is 22,557 SF (based on the maximum per zoning). The total impervious surface area that is being utilized in the drainage design for this project is 31,457 SF (maximum impervious surface area for the individual lots + short plat improvements). The proposed construction limits for this project not only include the parcel itself, but also the areas in the ROW for both NE 36th Street and Lincoln Ave NE in which frontage improvements will be installed. In the existing conditions, approximately 2,022 SF of area within the construction limits on the eastern side of Lincoln Avenue NE discharges runoff to the north (due to the road being crowned). This is the only area within the construction limits that discharges towards a separate basin than the rest of the construction limits. In the proposed conditions, approximately 5,131 SF of area within the construction limits will be discharged to this same separate basin to the north, as this proposed section of Lincoln Avenue NE will be graded at 2% towards the western curb line and cannot be mitigated with the rest of the proposed surfaces due to topography constraints. Therefore, stormwater runoff from the proposed development will be routed into two different basins – Basin 1 and Basin 2; Basin 1 is 1.194 AC, and Basin 2 is 0.046 AC (for a total construction limit area of 1.240 AC). Basin 1 will include the future impervious surfaces to be constructed on Lots 1-5 (22,557 SF total based on the maximum per zoning), the 1,770 SF asphalt access road, 308 SF of concrete driveway apron (out of 462 SF total), 4,262 SF of asphalt pavement widening (out of 4,803 SF total), 956 SF of concrete sidewalk (out of 1,648 SF total), and 128 SF of concrete ADA ramp (out of 217 SF total). All of the proposed impervious surfaces within Basin 1 will be collected and conveyed into a 25 FT x 50 FT x 12 FT deep detention vault located to the south of the site within the public ROW for NE 36th Street. This detention vault will discharge stormwater into an existing storm pipe which routes runoff towards May Creek. Basin 2 will include 154 SF of concrete driveway apron, 541 SF of asphalt pavement widening, 692 SF of concrete sidewalk, and 89 SF of concrete ADA ramp. All of the proposed impervious surfaces within Basin 2 will be collected and conveyed into the existing storm system within Lincoln Ave NE which routes runoff in the northern direction (separate direction from Basin 1). Please refer to Core Requirement #9 in Section II and Section IV of this TIR for additional discussion on stormwater BMPs and flow control. A Developed Conditions Map is provided as Figure 5 at this end of this Section. NE 36TH ST LI N C O L N A V E N E NO R T H LI N C O L N P E A K S H O R T P L A T 36 0 1 L I N C O L N A V E N E RE N T O N , W A 9 8 0 5 6 RE V I S I O N S JO B N O . DA T E SC A L E SH E E T En c o m p a s s Ea s t e r n W a s h i n g t o n D i v i s i o n 40 7 S w i f t w a t e r B l v d . ▪ Cle E l u m , W A 9 8 9 2 2 ▪ Ph o n e : ( 5 0 9 ) 6 7 4 - 7 4 3 3 We s t e r n W a s h i n g t o n D i v i s i o n 16 5 N E J u n i p e r S t r e e t , S u i t e 2 0 1 ▪ Is s a q u a h , W A 9 8 0 2 7 ▪ Ph o n e : ( 4 2 5 ) 3 9 2 - 0 2 5 0 EN G I N E E R I N G & S U R V E Y I N G FI G 3 EX I S T I N G C O N D I T I O N S ON-SITE IMPERVIOUS AREAS: OFF-SITE IMPERVIOUS AREAS: TOTAL IMPERVIOUS AREAS: 13,440 SF NE 36TH ST LI N C O L N A V E N E LOT 4LOT 5 LOT 3 ROW DEDICATION LOT 2 TRACT B LOT 1 TR A C T A NO R T H LI N C O L N P E A K S H O R T P L A T 36 0 1 L I N C O L N A V E N E RE N T O N , W A 9 8 0 5 6 RE V I S I O N S JO B N O . DA T E SC A L E SH E E T En c o m p a s s Ea s t e r n W a s h i n g t o n D i v i s i o n 40 7 S w i f t w a t e r B l v d . ▪ Cle E l u m , W A 9 8 9 2 2 ▪ Ph o n e : ( 5 0 9 ) 6 7 4 - 7 4 3 3 We s t e r n W a s h i n g t o n D i v i s i o n 16 5 N E J u n i p e r S t r e e t , S u i t e 2 0 1 ▪ Is s a q u a h , W A 9 8 0 2 7 ▪ Ph o n e : ( 4 2 5 ) 3 9 2 - 0 2 5 0 EN G I N E E R I N G & S U R V E Y I N G FI G 4 PR O P O S E D C O N D I T I O N S ON-SITE IMPERVIOUS AREAS: OFF-SITE IMPERVIOUS AREAS: TOTAL IMPERVIOUS AREAS: 8,900 SF Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 7 II. CONDITIONS AND REQUIREMENTS SUMMARY The 2022 City of Renton Surface Water Design Manual (RSWDM) was utilized to determine and address all core and special requirements. Based on the criteria specified in Figure 1.1.2.A of the RSWDM, the project falls under Full Drainage Review. Per Section 1.1.2.4 of the RSWDM, the project must meet all nine (9) core and all six (6) special requirements. See Figure 6 below for more information on how the type of drainage review was determined. Figure 6: Drainage Review Flow Chart Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 8 Core Requirements Core Requirement #1: Discharge at the Natural Location This project proposes a detention vault (for Basin 1) that will discharge runoff to the west where it eventually converges with May Creek. Runoff from the impervious surfaces within Basin 2 will be collected and conveyed into the existing storm system within Lincoln Avenue NE which routes runoff in the northern direction (separate direction from Basin 1). The stormwater mitigation within these two basins matches the existing drainage conditions. Please refer to the full Downstream Analysis provided in Section III of this TIR. Core Requirement #2: Downstream Analysis A Level 1 Downstream analysis has been completed for the site and no existing or potential problems have been identified. This analysis is included in Section III of this TIR. Core Requirement #3: Flow Control Facilities Based on the City of Renton’s flow control application map, the project site is located within the Duration Flow Control Standard (Forested Conditions). Flow control facilities are required to match the developed peak discharge rates to historical (forested) site conditions over the range of flows extending form 50% of the 2-year up to the full 50-year flow and match the peaks for the 2- and 10-year return periods. A 25 FT x 50 FT x 12 FT deep detention vault is proposed the meet stormwater requirements for Basin 1. This stormwater facility will be located to the south of the site within the public ROW for NE 36th Street. Stormwater runoff from Basin 2 will be collected and conveyed into the existing storm system within Lincoln Ave NE which routes runoff in the northern direction (separate direction from Basin 1). This basin is exempt from flow control, as the proposed surfaces in this area result in a 0.0942 CFS increase in the 100-year flow using 15-minute time steps, which is below the exemption threshold of 0.15 CFS. No flow control facilities are proposed at this time for Basin 2; however, flow control BMPs have been analyzed as described under Core Requirement #9. Please refer to Appendix D for a copy of the full WWHM data output. See Chapter IV of this TIR for additional discussion Core Requirement #4: Conveyance System Conveyance in compliance with the requirements detailed in Section 1.2.4.1 of the City of Renton 2022 SWDM is provided in Section V of this report. Core Requirement #5: Construction Stormwater Pollution Prevention A temporary erosion and sediment control (TESC) plan providing details on best management practices (BMPs) to be implemented during construction is included in the engineering plan set. A Construction Stormwater Pollution Prevention Plan (CSWPPP) will be provided with final engineering. Please refer to Section VIII of this TIR for additional discussion. Core Requirement #6: Maintenance and Operations An Operation and Maintenance Manual will be provided with final engineering. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 9 Core Requirement #7: Financial Guarantees and Liability The owner will arrange for any financial guarantees and liabilities required by the permit. Core Requirement #8: Water Quality Facilities In accordance with Section 1.2.8.1.A of the RSWDM, Basic Water Quality Treatment is required for this project as new plus replaced pollution generating impervious surfaces (PGIS) exceed 5,000 SF. To address water quality requirements, a Contech StormFilter catch basin is proposed post- detention for Basin 1. Core Requirement #9: Flow Control BMPs This project is classified as a small subdivision; therefore, it is subject to the Small Subdivision Project BMP Requirements detailed in Section 1.2.9.3.1 in the RSWDM (both Basin 1 and Basin 2 have been analyzed separately). Although implementation of individual lot BMPs is not required until building permit application, BMPs have been considered for the future improvements on Lots 1-5 based on Section 1.2.9.2.1 and of the RSWDM. See Section IV of this TIR for further discussion and flow control analysis. 1.2.9.3.1 Small Subdivision Project BMP Requirements (Basin 1) Full Dispersion: Infeasible. A 100-foot native vegetated flowpath segment is not available on-site for the 7,424 SF of impervious surfaces to be constructed within Basin 1 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project). Full Infiltration / Bioretention / Limited Infiltration / Permeable Pavement: Infeasible. The Geotechnical Report prepared by Terra Associates, Inc. (Appendix A) states that stormwater management at the site should not be managed with infiltration facilities, as the soils underling the site largely consist of silty sand which exhibit low permeabilities and would impede the downward migration of stormwater. Basic Dispersion: Infeasible. A 25-foot vegetated flowpath is not available on-site for the 7,424 SF of impervious surfaces to be constructed within Basin 1 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project). Soil Moisture Holding Capacity: The soil moisture holding capacity of new pervious surfaces must be protected in accordance with KCC 16.82.100 (F) and (G). KCC 16.82.100(F) requires that the duff layer or native topsoil be retained to the maximum extent practicable. KCC 16.82.100(G) requires soil amendment to mitigate for lost moisture holding capacity where compaction or removal of some or all of the duff layer or underlying topsoil has occurred. The amendment must be such that the replaced topsoil is a minimum of 8 inches thick, unless the applicant demonstrates that a different thickness will provide conditions equivalent to the soil moisture holding capacity native to the site. The replaced topsoil must have an organic content of 5-10% dry weight and a pH suitable for the proposed surface vegetation (for most soils in King County, 4 inches of well-rotted compost tilled into the top 8 inches of soil is sufficient to achieve the organic content standard.) The amendment must take place between May 1 and October 1. As no BMPs are feasible for the mitigation of the 7,424 SF of impervious surfaces to be constructed within Basin 1 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project), stormwater runoff will be collected and conveyed into a 25 FT x 50 FT x 12 FT deep Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 10 detention vault located to the south of the site within the public ROW for NE 36th Street (this vault will also be responsible for mitigating the 22,557 SF of maximum impervious per zoning on the individual lots). This detention vault will discharge stormwater into an existing storm pipe which routes runoff towards May Creek. A Developed Conditions Map is provided as Figure 5 of this report. 1.2.9.3.1 Small Subdivision Project BMP Requirements (Basin 2) Full Dispersion: Infeasible. A 100-foot native vegetated flowpath segment is not available on-site for the 1,476 SF of impervious surfaces to be constructed within Basin 2 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project). Full Infiltration / Bioretention / Limited Infiltration / Permeable Pavement: Infeasible. The Geotechnical Report prepared by Terra Associates, Inc. (Appendix A) states that stormwater management at the site should not be managed with infiltration facilities, as the soils underling the site largely consist of silty sand which exhibit low permeabilities and would impede the downward migration of stormwater. Basic Dispersion: Infeasible. A 25-foot vegetated flowpath is not available on-site for the 1,476 SF of impervious surfaces to be constructed within Basin 2 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project). Soil Moisture Holding Capacity: The soil moisture holding capacity of new pervious surfaces must be protected in accordance with KCC 16.82.100 (F) and (G). KCC 16.82.100(F) requires that the duff layer or native topsoil be retained to the maximum extent practicable. KCC 16.82.100(G) requires soil amendment to mitigate for lost moisture holding capacity where compaction or removal of some or all of the duff layer or underlying topsoil has occurred. The amendment must be such that the replaced topsoil is a minimum of 8 inches thick, unless the applicant demonstrates that a different thickness will provide conditions equivalent to the soil moisture holding capacity native to the site. The replaced topsoil must have an organic content of 5-10% dry weight and a pH suitable for the proposed surface vegetation (for most soils in King County, 4 inches of well-rotted compost tilled into the top 8 inches of soil is sufficient to achieve the organic content standard.) The amendment must take place between May 1 and October 1. As no BMPs are feasible for the mitigation of the 1,476 SF of impervious surfaces to be constructed within Basin 2 of the short plat (out of 8,900 SF total short plat improvements associated with the entire project), stormwater runoff will be collected and conveyed into the existing storm system within Lincoln Ave NE which routes runoff in the northern direction (separate direction from Basin 1). A Developed Conditions Map is provided as Figure 5 of this report. 1.2.9.2.1 Small Lot BMP Requirements The maximum impervious surface coverage allowed per zoning is 65%. For the design of Lots 1-5, the maximum impervious surface coverage was assumed while evaluating future stormwater BMPs. Their final location and design shall be determined under the single-family building permit process. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 11 Full Dispersion: Infeasible. A 100-foot native vegetated flowpath segment is not available on any of the proposed lots. Full Infiltration / Bioretention / Limited Infiltration / Permeable Pavement: Infeasible. The Geotechnical Report prepared by Terra Associates, Inc. (Appendix A) states that stormwater management at the site should not be managed with infiltration facilities, as the soils underling the site largely consist of silty sand which exhibit low permeabilities and would impede the downward migration of stormwater. Basic Dispersion: Basic Dispersion may be feasible on the proposed lots, depending on the building footprints/layout for the future single-family residences. Conservatively, it has been deemed infeasible and all runoff produced from the future development of Lots 1-5 has been designed to be directed into the proposed 25 FT x 50 FT x 12 FT deep detention vault located south of the site within the public ROW for NE 36th Street. As no BMPs are feasible, stormwater runoff from the maximum impervious surface area associated with the individual lots (22,557 SF – based on the maximum per zoning) will be collected and conveyed into a 25 FT x 50 FT x 12 FT deep detention vault located to the south of the site within the public ROW for NE 36th Street. This detention vault will discharge stormwater into an existing storm pipe which routes runoff towards May Creek. A Developed Conditions Map is provided as Figure 5 of this report. Special Requirements Special Requirement #1: Other Adopted Area-Specific Requirements Critical Drainage Area – N/A Master Drainage Plan – N/A Basin Plan – N/A Lake management Plan – N/A Shared Facility Drainage Plan – N/A Special Requirement #2: Flood Hazard Area Delineation The limits of this project do not lie within a delineated FEMA 100-year floodplain. Special Requirement #3: Flood Protection Facilities This project does not rely on or propose to modify/construct a new flood protection facility. Special Requirement #4: Source controls Source controls for the proposed short plat development are not applicable. Special Requirement #5: Oil Control This project is not considered high-use in need of oil control. Special Requirement #6: Aquifer Protection Area The site is not located within an Aquifer Protection Area per the Groundwater Protection Areas Map in the RSWDM. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 12 III. DOWNSTREAM ANALYSIS A Level 1 Downstream analysis has been conducted per the requirements in Section 1.2.2.1 of the RSWDM. Please see Tasks 1 through 4 below for a summary of the results. Task 1: Define and Map the Study Area It should be noted that the property itself only contains one natural discharge area (NDA); however, as the proposed construction limits for the project extend past the property boundaries and into the public ROW, it was found that a small portion within the northeastern section of the construction limits (on Lincoln Avenue NE) drains to a separate basin than the property itself. Therefore, this site contains two separate drainage basins – Basin 1 and Basin 2. The area of analysis extends approximately a quarter-mile downstream from the site. A Downstream Map is provided in Figure 7 below. Figure 7: Downstream Map Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 13 Task 2: Review All Available Information on the Study Area Per King County resources, there have been no significant drainage complaints within a quarter-mile downstream of the site. Task 3: Field Inspect the Study Area A field inspection was performed by Encompass Engineering & Surveying on October 3rd, 2025. Please refer to Task 4 for a detailed description of the downstream drainage system and analysis. Task 4: Describe the Drainage System It should be noted that the property itself only contains one natural discharge area (NDA); however, as the proposed construction limits for the project extend past the property boundaries and into the public ROW, it was found that a small portion within the northeastern section of the construction limits (on Lincoln Avenue NE) drains to a separate basin than the property itself. Therefore, this site contains two separate drainage basins – Basin 1 and Basin 2. Basin 1: Stormwater runoff produced from within the construction limits in the existing conditions for Basin 1 leaves from the natural discharge location in the northwestern/western portion of the site. Stormwater from the site begins by sheet flowing to the northwest over moderate slopes ranging from 2- 15% in the eastern portion of the site; once the stormwater reaches the western portion of the site, it reaches a steep slope area with slopes of up to 75% where it continues to sheet flow off site through the natural discharge location (Basin 1 - A). Once stormwater leaves the site, it continues to sheet flow over steep slopes and through neighboring lots in the northwestern direction until eventually reaching Jones Ave NE approximately 450 feet downstream of the subject site (Basin 1 - B). Once reaching Jones Ave NE, the stormwater sheet flows across the asphalt street and continues to follow the natural topography to the west. After approximately 250 more feet, the runoff would eventually converge with May Creek (Basin 1 - C). After the stormwater converges with May Creek, it is conveyed in the northern direction following the natural flow path of the creek. At the ¼ mile downstream limit, stormwater is still being conveyed in the northern direction within May Creek. Basin 2: Stormwater runoff produced from within the construction limits in the existing conditions for Basin 2 sheet flows towards the eastern side of Lincoln Ave NE and converges with a catch basin located along the eastern side of the street (Basin 2 - A). From here, the storm public stormwater system conveys stormwater north beneath Lincoln Avenue NE until the ¼ mile downstream limit is reached. It should be noted that per Renton’s GIS Mapping System, the storm system in Lincoln Ave NE does not appear to discharge runoff into the stream that passes through Lincoln Ave NE (Basin 2 - B). No drainage related issues were observed downstream of the site for either drainage basin, and no relevant drainage complaints were identified on the King County iMap system within a quarter mile of the site discharge location. Please refer to Figure 7 on the previous page for the approximate location of identified drainage features. Photographs from the site visit are included below. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 14 Basin 1 (A) – Runoff sheet flows northwest towards the natural discharge location (edge of steep slope seen in photograph) Basin 1 (B) – Runoff sheet flows over Jones Ave NE to the west Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 15 Basin 1 (C) – Runoff converges with May Creek Basin 2 (A) – Runoff enters stormwater system along eastern side of Lincoln Ave NE Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 16 Basin 2 (B) – Storm system appears to convey runoff north through the intersection of Lincoln Ave NE & NE 40th Street (Per Renton GIS Mapping System, the storm system does not converge with the unnamed stream that can be seen on the Downstream Drainage Map) Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 17 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Part A: Existing Site Hydrology This property is located within the May Creek drainage basin, within the Cedar River/Lake Washington watershed. The 48,066 SF (1.10 AC) site is currently developed with a single-family residence, detached garage, gravel driveway, and concrete driveway. Stormwater runoff produced from the existing site sheet flows towards the natural discharge area (NDA) located in the western portion of the site. The eastern portion of the site contains moderate slopes ranging from 2-15%, and the western portion of the site contains steep slopes of up to 75%. Stormwater ultimately converges with May Creek, located approximately 700 feet west of the site. See the full downstream analysis in Section III of this Technical Information Report (TIR). The Geotechnical Report prepared by Terra Associates, Inc. (Appendix A) states that stormwater management at the site should not be managed with infiltration facilities, as the soils underling the site largely consist of silty sand which exhibit low permeabilities and would impede the downward migration of stormwater. Part B: Developed Site Hydrology The project proposes the development of five (5) single-family lots within the 48,066 SF (1.10 AC) parcel. Lot 1 is 7,333 SF and will be located in the northeastern portion of the site, Lot 2 is 7,690 SF and will be located in the northwestern portion of the site, Lot 3 is 6,036 SF and will be located in the southeastern portion of the site, Lot 4 is 6,095 SF and will be located directly west of Lot 3, and Lot 5 is 7,552 SF and will be located in the southwestern portion of the site. A 1,770 SF private access tract (Tract A) is proposed between Lots 4 and 5 and will provide access to Lots 2 and 5 via NE 36th Street in the southern portion the site, a 4,358 SF critical area tract (Tract B) will be located along the western edge of the site, and a 7,233 SF ROW dedication is proposed along the southern and eastern property boundaries. The proposed impervious surfaces associated with this short plat include a 1,770 SF asphalt access road, 462 SF of concrete driveway aprons, 4,803 SF of asphalt pavement widening, 1,648 SF of concrete sidewalk, and a 217 SF concrete ADA ramp (for a total of 8,900 SF of impervious surfaces). The total impervious surface area associated with the individual lots is 22,557 SF (based on the maximum per zoning). The total impervious surface area that is being utilized in the drainage design for this project is 31,457 SF (maximum impervious surface area for the individual lots + short plat improvements). All of the proposed impervious surfaces within Basin 1 will be collected and conveyed into a 25 FT x 50 FT x 12 FT deep detention vault located to the south of the site within the public ROW for NE 36th Street. This detention vault will discharge stormwater into an existing storm pipe which routes runoff towards May Creek. All of the proposed impervious surfaces within Basin 2 will be collected and conveyed into the existing storm system within Lincoln Ave NE which routes runoff in the northern direction (separate direction from Basin 1). WWHM 2012 was used to model the proposed condition using target surfaces per Section 1.2.3 of the 2022 RSWDM. It should be noted that within the 54,033 SF (1.240 AC) clearing limits, there are two drainage basins (Basin 1 & Basin 2). Each of the basin areas are different in the developed conditions than in the existing conditions due to the additional pavement on Lincoln Avenue that will be conveyed north when developed. The maximum impervious area per zoning for the future lot developments has been modeled as rooftop. Approximately 3,220 SF of existing pavement on Lincoln Ave NE in Basin 2 that will Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 18 have a grind and overlay done has been included in the developed conditions model. A summary of the analyses is provided in the tables below: Existing Developed Condition Measured Modeled Measured Modeled C, Forest, Mod: 1.194 AC 1.194 AC C, Lawn, Mod: 0.437 AC 0.437 AC Roof Tops/Flat: 0.518 AC 0.518 AC Roads/Flat: 0.138 AC 0.138 AC Driveways/Flat: 0.007 AC 0.007 AC Sidewalks/Flat: 0.022 AC 0.022 AC Total Area: 1.194 AC 1.194 AC 1.122 AC 1.122 AC WWHM Conditions Model (Basin 1) Existing Developed Condition Measured Modeled Measured Modeled C, Forest, Mod: 0.046 AC 0.046 AC C, Lawn, Mod: 0.012 AC 0.012 AC Roof Tops/Flat: Roads/Mod: 0.086 AC 0.086 AC Driveways/Flat: 0.004 AC 0.004 AC Sidewalks/Flat: 0.016 AC 0.016 AC Total Area: 0.046 AC 0.046 AC 0.118 AC 0.118 AC WWHM Conditions Model (Basin 2) Part C: Performance Standards Based on the City of Renton’s flow control application map, the project site is located within the Duration Flow Control Standard (Forested Conditions). Flow control facilities are required to match the developed peak discharge rates to historical (forested) site conditions over the range of flows extending form 50% of the 2-year up to the full 50-year flow and match the peaks for the 2- and 10-year return periods. This project is classified as a small subdivision; therefore, it is subject to the Small Subdivision Project BMP Requirements detailed in Section 1.2.9.3.1 in the RSWDM. Although implementation of individual lot BMPs is not required until building permit application, BMPs have been considered for the future improvements on Lots 1-3 based on Section 1.2.9.2.1 and of the RSWDM. The site falls within a Basic Water Quality treatment area in accordance with Section 1.2.8.1.A of the RSWDM. Part D: Flow Control System Flow control will be provided for Basin 1 with a 25 FT x 50 FT x 12 FT deep detention vault located to the south of the site within the public ROW for NE 36th Street. This detention vault will discharge stormwater into an existing storm pipe which routes runoff towards May Creek. A Contech StormFilter catch basin is proposed after the control structure in order to provide water quality for the pollution generating impervious surfaces. Per WWHM modeling, the required storage volume of the system is 14,985 CF (0.344 ac-ft). The proposed vault has a provided volume of 15,000 CF. Stormwater runoff from Basin 2 will be collected and conveyed into the existing storm system within Lincoln Ave NE which routes runoff in the northern direction (separate direction from Basin 1). This basin Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 19 is exempt from flow control, as the proposed surfaces in this area result in a 0.0942 CFS increase in the 100-year flow using 15-minute time steps, which is below the exemption threshold of 0.15 CFS. Please refer to Appendix B for a copy of the full WWHM data output. See WWHM data inputs for the Basin 1 detention system and the flow frequency output for Basin 2 below: Basin 1 Detention Vault Basin 2 Flow Frequency (0.0942 CFS < 0.15 CFS √) Part E: Water Quality System In accordance with Section 1.2.8.1.A of the RSWDM, Basic Water Quality Treatment is required for this project as new plus replaced pollution generating impervious surfaces (PGIS) exceed 5,000 SF. To address water quality requirements, a Contech StormFilter catch basin is proposed post-detention for Basin 1. Lincoln Peak Short Plat Preliminary Technical Information Report 11/12/2025 P a g e | 20 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN Conveyance system analysis and design will be completed with final engineering. VI. SPECIAL REPORTS AND STUDIES • Geotechnical Report by Terra Associates, Inc. dated July 23, 2025 • Wetland and Stream Reconnaissance by Wetland Resources, Inc. dated April 15, 2025 • Preliminary Tree Protection Plan by Washington Forestry Consultants, Inc. dated May 28, 2025 VII. OTHER PERMITS • Civil Construction Permit • Building Permits • Right-of-Way Use Permit VIII. CSWPP ANALYSIS AND DESIGN A CSWPPP will be provided with final engineering. IX. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION of COVENANT Bond Quantities, Facility Summaries, and a Declaration of Covenant will be provided with final engineering. X. OPERATION AND MAINTENANCE MANUAL An Operation and Maintenance Manual will be provided with final engineering. Appendix A Geotechnical Report by Terra Associates, Inc. dated July 23, 2025 Appendix B Wetland and Stream Reconnaissance by Wetland Resources, Inc. dated April 15, 2025 9505 19th Avenue SE, Suite 106, Everett, WA 98208 425.337.3174 www.wetlandresources.com April 15, 2025 JKM Holdings, LLC Attn: Geoffrey Sherwin PO Box 188 Puyallup, WA 98371 RE: Wetland and Stream Reconnaissance – 3601 Lincoln Avenue NE, Renton, WA Wetland Resources, Inc. (WRI) performed a site investigation on April 7, 2025, at the 1.10-acre property located at the address referenced above. The King County tax identification number for the subject parcel is 3345700230. The site is located within the May Creek sub-basin of the Cedar River/Lake Washington watershed, Water Resource Inventory Area 8. The Public Land Survey System (PLSS) locator for this parcel is Section 32, Township 24, Range 5E, W.M. The parcel is developed with a single-family residence, a shop/garage, and driveway. Vegetation near the house is maintained landscaping and lawn and a row of trees is present along the western edge of the parcel. The site is relatively flat, with a west-facing slope beginning near the western property line. Surrounding land use is generally single-family residential. May Creek, May Creek Park, and associated undeveloped open space is located to the west/southwest of the parcel. The purpose of this report is to present information related to wetlands and streams on and in the vicinity of the subject parcel. Landslide, erosion, and other geological hazard areas are beyond the scope of this report. REVIEW OF EXISTING INFORMATION Prior to conducting the site investigation, public resource information was reviewed to gather background information on the subject property and the surrounding area regarding wetlands, streams, and other critical areas. These sources include the following: • United States Fish and Wildlife Service (USFWS) National Wetlands Inventory (NWI): This resource maps a riverine feature (May Creek) to the west, on the west side of Jones Avenue NE. • USDA/NRCS Web Soil Survey: The Web Soil Survey indicates that the property is underlain by Alderwood gravelly sandy loam, 8 to 15 percent slopes. • WDFW Priority Habitat and Species (PHS) Interactive Map: The PHS Interactive Map maps May Creek off site to the west. This stream is listed as habitat for Chinook salmon, sockeye salmon, coho salmon, and steelhead trout. Wetland Resources, Inc. Lincoln Avenue Reconnaissance Report April 15, 2025 WRI #25103 2 • King County iMap: King County depicts May Creek to the west of the site, on the west side of Jones Avenue NE. • City of Renton interactive GIS map: This resource maps May Creek and an associated wetland over 300 feet off site to the west. Another wetland is mapped approximately 100 feet to the south of the property. Landslide and erosion hazard areas are shown in the western portion of the site. Geologically hazardous areas are outside of the scope for this report. METHODOLOGY The Washington State Department of Ecology document Determining the Ordinary High Water Mark for Shoreline Management Act Compliance in Washington State (Anderson et al. 2016) was used to determine the presence of any streams on the subject site. Wetland areas were determined using the routine determination approach described in the Corps of Engineers Wetlands Delineation Manual (Environmental Laboratory 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0) (U.S. Army Corps of Engineers 2010). Under the routine methodology, the process for making a wetland determination is based on three steps: 1) Examination of the site for hydrophytic vegetation (species present and percent cover); 2) Examination of the site for hydric soils; 3) Determining the presence of wetland hydrology The wetland identified was rated pursuant to the Washington State Wetland Rating System for Western Washington: 2014 Update as required by Renton Municipal Code (RMC) 4-3-050G.9.c. Please note the wetland ratings presented in this report are based on preliminary information and are subject to change if the wetlands are formally delineated. FINDINGS On-site vegetation near the residence includes Japanese maples, wisteria, rhododendrons, and other installed landscaping plants. Native vegetation observed near the western boundary of the site includes big leaf maple (Acer macrophyllum; FACU), western hemlock (Tsuga heterophylla; FACU), snowberry (Symphoricarpos albus; FACU), and sword fern (Polystichum munitum; FACU). Sampled soils were dry and generally very dark brown (10YR 2/2) in the upper layer and dark brown (10YR 3/3) in the second layer. Soil texture was typically loam or sandy loam across the site. Given the lack of hydrophytic vegetation, wetland hydrology, or hydric soil indicators, there are no wetland areas present on the property. No flowing water, channels, scours, or sorted material were observed on the site; therefore, there are no streams on the site. Off-site Wetlands and Streams May Creek and an adjacent wetland are approximately 320 feet to the west/southwest of the site. Since May Creek and the adjacent wetland are over 300 feet from the subject property, these features do not cast a buffer onto the parcel. Shoreline jurisdiction would extend 200 feet from the edge of these features and per the City of Renton’s GIS map information, the shoreline environment associated with May Creek terminates west of the site. Wetland Resources, Inc. Lincoln Avenue Reconnaissance Report April 15, 2025 WRI #25103 3 A second wetland mapped by the City of Renton is present a little over 100 feet to the south the of property. This wetland (Wetland A) was evaluated and is discussed below. Wetland A (Off-site) HGM Category: Slope Wetland Rating Category: III City of Renton Buffer: 100 feet Wetland A is a located approximately 100 feet south of the subject property along a sloped area east of Jones Avenue NE. As this wetland is off-site, information about this wetland was gathered from aerial imagery, publicly available resources like the City of Renton interactive map, and observations from adjacent rights-of-way. Vegetation in Wetland A includes black cottonwood (Populus balsamifera; FAC), red alder (Alnus rubra; FAC), Himalayan blackberry (Rubus armeniacus; FAC), horsetail (Equisetum sp.), and reed canarygrass (Phalaris arundinacea; FACW). Saturation and standing water were observed at the toe of the slope, along the west side of Jones Avenue NE. As the wetland is located off of the property, soils within the wetland area were not sampled. Wetland A is a Category III wetland with a moderate habitat score. Per RMC 4-3-050G.2, this wetland requires a 100-foot buffer and a 15-foot building setback from the wetland buffer. USE OF THIS REPORT This Wetland and Stream Reconnaissance Report has been prepared for JKM Holdings, LLC to assist with identifying on-site and nearby critical areas as required by the City of Renton. This report is based largely on readily observable conditions and, to a lesser extent, on readily ascertainable conditions. No attempt has been made to determine hidden or concealed conditions. The laws applicable to critical areas are subject to varying interpretations and may be changed at any time by the courts or legislative bodies. This report is intended to provide information deemed relevant in the applicant's attempt to comply with the laws now in effect. This report conforms to the standard of care employed by ecologists. No other representation or warranty is made concerning the work or this report and any implied representation or warranty is disclaimed. Wetland Resources, Inc. Meryl Kamowski, PWS Senior Ecologist Enclosure: Reconnaissance Map Appendix C Preliminary Tree Protection Plan by Washington Forestry Consultants, Inc. dated May 28, 2025 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- 3601 Lincoln Avenue NE 3601 Lincoln Avenue NE Renton, WA 98055 Prepared for: Prepared by: Washington Forestry Consultants, Inc. Date of Report: May 28, 2025 Introduction The project proponent is planning to construct a new 5 lot short plat on one parcel totaling 1.10-acres at 3601 Lincoln Avenue NE 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 protectionand cultural measures. •Complete the City of Renton Tree Retention and Credit Worksheet. 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. 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. JKM Holdings, LLC 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 2 Site Description The project site consists of one 1.10-acre parcel, #3345700230. A single-family home and associated outbuildings are on the site. Most of the parcel is gently sloping to the west with very steep slopes on the western edge. There is a ~0.23-acre steep slope critical area in this part of the site. The site is bordered by single-family homes to the north, south, and west, and Lincoln Avenue to the east. Soils Description According to the USDA Natural Resource Conservation Service soil survey the three soil types in the project area are variants of the Alderwood gravelly sandy loam, a moderately deep, moderately well drained soil found on glacial till plains. It is formed in ablation till overlying basal till. A weakly cemented hardpan is at a depth of 20 to 40 inches. Permeability is moderately rapid above the hardpan and very slow in the pan. Available water capacity is low. Effective rooting depth is 20-40 inches. A perched seasonal high-water table is at a depth of 18-36 inches from Novemberto March. The potential for windthrow of trees is moderate under normal conditions. New trees require irrigation for establishment. In areas where grading brings the hardpan nearer to thesurface, the hardpan must be fractured under new trees to provide soil volume for rootdevelopment and to improve drainage around the tree. Figure 1. 3601 Lincoln Avenue NE Soils Map AgC - Alderwood gravelly sandy loam 8 – 15% slope AgD – Alderwood gravelly sandy loam 15 – 30% slope AkF – Alderwood and Kitsap soils – very steep 3601 Lincoln Avenue NE – 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 includes the entire buildable area of the project site. There are a total of 29 trees in the type. There are introduced trees planted around the home and naturally seeded trees throughout the site. The size of significant trees ranges from 6 inches to 41 inches in diameter at breast height (DBH). Tree species include bigleaf maple (Acer macrophyllum), black cottonwood (Populus trichocarpa), Callery pear (Pyrus calleryana), giant sequoia (Sequoiadendron giganteum), common hawthorn (Crataegus monogyna), noble fir (Abies procera), smoke tree (Cotinus coggygria), weeping willow (Salix babylonica), and western hemlock (Tsuga heterophylla). Tree conditions on the site range from ‘Poor’ to ‘Good,’ with 93% being rated in ‘Fair’ or better condition. Twenty-seven of the 29 significant trees could be potentially retained on this site when only tree health is considered. The remaining trees are multi-stemmed resprouted stumps that are not quality formed trees to save. Common hawthorn is classified as a Non-Regulated Noxious Weed in King County. The eight Landmark sized trees on the project site are healthy. Sixteen of the trees are located in a steep slope critical area. Table 1. Summary of trees on 3601 Lincoln Avenue NE Site. Species DBH Range (in.) # of Healthy Trees # of Unhealthy Trees* Total # of Trees # of Landmark Trees** Bigleaf Maple 6 – 12 11 2 13 3 Black Cottonwood 9 – 11 2 0 2 0 Callery Pear 9 – 11 4 0 4 0 Giant Sequoia 28 – 36 3 0 3 3 Hawthorn 12 1 0 1 0 Noble Fir 12 1 0 1 0 Smoke Tree 8 1 0 1 0 Weeping Willow 41 1 0 1 1 Western Hemlock 19 3 0 3 1 Sum 6 – 41 27 2 29 8 *Trees rated as dead, very poor, or poor. ** Trees ≥24” DBH, bigleaf maple, red alder, cottonwood ≥30” DBH The understory vegetation throughout the type is grass, weeds, and other planted shrubs in the landscape. Himalayan blackberry (Rubus armeniacus) covers a large portion of the site. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 4 Photo 1: View of trees on the 3601 Lincoln Avenue NE Site. Off-site Impacts No off-site trees will be impacted from tree removal or grading of this project. Discussion Potential for Tree Retention The site plan shows no trees being retained on the buildable area of the site. The on-site trees are all under the footprints of improvements. This includes one Landmark sized weeping willow. Sixteen trees will be saved in the critical area. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 5 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 29 significant sized trees on the parcel. After allowed tree deductions 6 trees remain for calculating the 30% requirement. A total of 2 significant trees will need to be retained in the project area to meet the requirement. Total # of Significant Trees: 29 Trees # of High Risk Significant Trees: 0 Trees # of Trees in Steep Slope Critical Area: 16 Trees # of Trees in the Public Rights-of-Ways: 9 Trees # of Significant Trees After Deductions: 4 Trees # of Significant Trees Required to be Saved (30% of 4 Trees): 1 Tree # of Significant Trees Planned to be Saved 0 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: 1.10 Acres Proposed Rights-of-way Acreage: 0.32 Acres Critical Area Acreage: 0.23 Acres Net Developable Acres: 0.55 Acres Required Tree Credit Density (0.55 Acres x 30 Credits/Acre): 17 Tree Credits Proposed Tree Retention: Developed Area (0 trees) 0.0 Tree Credits Shortfall of Tree Credit Requirement: 17.0 Tree Credits By retaining no trees in the buildable area of the site this plan falls short of the minimum significant tree retention requirement by 17 trees. Planned tree credit retention is less than the minimum tree credits by 17.0 credits. Seventeen tree credits will be required to replace the minimum credit 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 topography of the site requires significant grading to complete the project. The small lots, location 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 6 of trees, grading, and required road improvements and utilities eliminates the number of trees that can be retained on the 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 8). 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. 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 construction). 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®. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 7 Conclusions and Timeline for Activity 1. No trees outside of the critical area 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. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 8 Summary The City of Renton Municipal Code calls for 1 of the healthy, significant trees and 17.0 tree credits be retained on the site. Based on the current site plan no trees will be retained because all healthy, significant trees in the buildable area are under the footprint of proposed improvements. An additional 34 trees will be required to replace the 30% significant tree requirement and tree credit shortfall. 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 (2014-24) Urban Forest Professional, PN- 5939AM ASCA Tree and Plant Appraisal Qualified ISA Tree Risk Assessor Qualified 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 9 Attachment 1. Aerial Photo of 3601 Lincoln Avenue NE Site (2023 King County) Parcel Area Boundary Critical Area Healthy Tree Unhealthy Tree 1 2 3 4 5 6 7 8 9 10 11 12 13 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 10 Attachment 2. 3601 Lincoln Avenue NE Site Plan Project Area Boundary Tree Protection Fence Location 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 11 Attachment 3. List of Trees on 3601 Lincoln Avenue NE Tree # Species DBH (in.) Calculated DBH (in.) Condition Average Dripline (feet) Landmark Tree Save Based on Condition Alone? Yes or No Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment 1 Callery Pear 11 Fair 10 Yes 10 Remove 5 topped for powerline 2 Callery Pear 9 Fair 10 Yes 10 Remove 4 topped for powerline 3 Callery Pear 9 Fair 10 Yes 10 Remove 4 topped for powerline 4 Callery Pear 11 Fair 10 Yes 10 Remove 5 topped for powerline 5 Hawthorn 12 Good 12 Yes 12 Remove 6 6 Western Hemlock 13, 14 19 Good 16 Yes 16 Remove 8 7 Weeping Willow 41 Good 20 Yes Yes 30 Remove 13 8 Smoke Tree 8 Fair 8 Yes 8 Remove 4 9 Black Cottonwood 10, 11 15 Good 12 Yes 12 Remove 6 no # 10 Black Cottonwood 9 Good 10 Yes 10 Remove 4 no # 11 Bigleaf Maple 3 - 6 10 Poor 8 No 8 Remove 5 5 stem sprouted stump 12 Bigleaf Maple 6 Good 10 Yes 10 Remove 4 13 Bigleaf Maple 3 -5 12 Poor 10 No 10 Remove 5 8 stem sprouted stump 14 Bigleaf Maple 24 Good Yes Yes Save in steep slope critical area 15 Bigleaf Maple 18 Good Yes Save in steep slope critical area 16 Bigleaf Maple 17 Good Yes Save in steep slope critical area 17 Bigleaf Maple 9 Good Yes Save in steep slope critical area 18 Bigleaf Maple 9 Good Yes Save in steep slope critical area 19 Bigleaf Maple 20 Good Yes Save in steep slope critical area 20 Bigleaf Maple 14 Good Yes Save in steep slope critical area 21 Bigleaf Maple 34 Good Yes Yes Save in steep slope critical area 22 Bigleaf Maple 26 Good Yes Yes Save in steep slope critical area 3601 Lincoln Avenue NE – 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 Tree Protection Zone (feet) Project Plan. Save or Remove Tree Credits Comment 23 Bigleaf Maple 14 Good Yes Save in steep slope critical area 24 Giant Sequoia 36 Good Yes Yes Save in steep slope critical area 25 Giant Sequoia 30 Good Yes Yes Save in steep slope critical area 26 Giant Sequoia 28 Good Yes Yes Save in steep slope critical area 27 Western Hemlock 24 Good Yes Yes Save in steep slope critical area 28 Western Hemlock 20 Good Yes Save in steep slope critical area 29 Noble Fir 12 Good Yes Save in steep slope critical area 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 13 Attachment 4. City of Renton Tree Retention and Credit Worksheet (3 pages) 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 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: 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: 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 14 Attachment 5. Individual Tree Rating Key for Tree Condition RATING SYMBOL DEFINITION Very Good VG • Balanced crown that is characteristic of the species • Normal lateral and terminal branch growth rates for the species and soil type • Stem sound, normal bark vigor • No root problems • No insect or disease problems • Long-term, attractive tree Good G • Crown lacking symmetry but nearly balanced • Normal lateral and terminal branch growth rates for the species and soil type • Minor twig dieback O.K. • Stem sound, normal bark vigor • No root problems • No or minor insect or disease problems – insignificant • Long-term tree Fair F • Crown lacking symmetry due to branch loss • Slow lateral and terminal branch growth rates for the species and soil type • Minor and major twig dieback – starting to decline • Stem partly unsound, slow diameter growth and low bark vigor • Minor root problems • Minor insect or disease problems • Short-term tree 10-30 years RATING SYMBOL DEFINITION Poor P • Major branch loss – unsymmetrical crown • Greatly reduced growth • Several structurally import dead or branch scaffold branches • Stem has bark loss and significant decay with poor bark vigor • Root damage • Insect or disease problems – remedy required • Short-term tree 1-10 years Very Poor VP • Lacking adequate live crown for survival and growth • Severe decline • Minor and major twig dieback • Stem unsound, bark sloughing, previous stem or large branch failures, very poor bark vigor • Severe root problems or disease • Major insect or disease problems • Mortality expected within the next few years Dead DEAD • Dead 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 15 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. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 16 Attachment 6. Description of Tree Evaluation Methodology The evaluation of the tree condition on this site included the visual assessment of: 1. Live-crown ratio, 2. Lateral and terminal branch growth rates, 3. Presence of dieback in minor and major scaffold branches and twigs, 4. Foliage color, 5. Stem soundness and other structural defects, 6. Visual root collar examination, 7. Presence of insect or disease problems. 8. Windfirmness if tree removal will expose this tree to failure. In cases where signs of internal defect or disease were suspected, a core sample was taken to look for stain, decay, and diameter growth rates. Also, root collars were exposed to look for the presence of root disease. In all cases, the overall appearance of the tree was considered relative to its ability to add value to either an individual lot or the entire subdivision. Also, the scale of the tree and its proximity to both proposed and existing houses was considered. Lastly, the potential for incorporation into the project design is evaluated, as well as potential site plan modifications that may allow otherwise removed tree(s) to be both saved and protected in the development. Trees that are preserved in a development must be carefully selected to make sure that they can survive construction impacts, adapt to a new environment, and perform well in the landscape. Healthy, vigorous trees are better able to tolerate impacts such as root injury, changes in soils moisture regimes, and soil compaction than are low vigor trees. Structural characteristics are also important in assessing suitability. Trees with significant decay and other structural defects that cannot be treated are likely to fail. Such trees should not be preserved in areas where damage to people or property could occur. Trees that have developed in a forest stand are adapted to the close, dense conditions found in such stands. When surrounding trees are removed during clearing and grading, the remaining trees are exposed to extremes in wind, temperature, solar radiation, which causes sunscald, and other influences. Young, vigorous trees with well-developed crowns are best able to adapt to these changing site conditions. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 17 Attachment 7. 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. 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 18 Attachment 8. Tree Protection Fence Detail 6 ft. Temporary Chain Link Fence NO TRESPASSING - Protected Trees 3601 Lincoln Avenue NE – Preliminary Tree Protection Plan Washington Forestry Consultants, Inc. Page 19 Attachment 9. 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 formatters 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 othergovernmental 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 theaccuracy of information. 4)Washington Forestry Consultants, Inc. shall not be required to give testimony or to attend court by reason ofthis report unless subsequent contractual arrangements are made, including payment of an additional fee forsuch 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 anyother than the person to whom it is addressed, without the prior expressed written or verbal consent ofWashington Forestry Consultants, Inc. 7)Neither all or any part of the contents of this report, nor copy thereof, shall be conveyed by anyone, includingthe client, to the public through advertising, public relations, news, sales or other media, without the priorexpressed written or verbal consent of Washington Forestry Consultants, Inc. -- particularly as to valueconclusions, identity of Washington Forestry Consultants, Inc., or any reference to any professional society orto 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 occurrenceneither 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 toscale 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 visualexamination of accessible items without dissection, excavation, probing, or coring. There is no warranty orguarantee, expressed or implied, that problems or deficiencies of the tree or other plant or property in questionmay 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. Appendix D WWHM Output WWHM2012 PROJECT REPORT Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 2 General Model Information WWHM2012 Project Name:Split Basin Model (2025-11-05) Site Name:Lincoln Peak Short Plat Site Address:3601 Lincoln Ave NE City:Renton Report Date:11/5/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2024/10/15 Version:4.3.1 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 1.194 Pervious Total 1.194 Impervious Land Use acre Impervious Total 0 Basin Total 1.194 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 1 POC 1 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 4 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 0.046 Pervious Total 0.046 Impervious Land Use acre Impervious Total 0 Basin Total 0.046 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 5 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Mod 0.437 Pervious Total 0.437 Impervious Land Use acre ROADS FLAT 0.138 ROOF TOPS FLAT 0.518 DRIVEWAYS FLAT 0.007 SIDEWALKS FLAT 0.022 Impervious Total 0.685 Basin Total 1.122 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: Vault 1 Vault 1 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 6 Basin 2 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.012 Pervious Total 0.012 Impervious Land Use acre ROADS MOD 0.086 DRIVEWAYS FLAT 0.004 SIDEWALKS FLAT 0.016 Impervious Total 0.106 Basin Total 0.118 Element Flow Componants: Surface Interflow Groundwater Componant Flows To: POC 2 POC 2 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 8 Mitigated Routing Vault 1 Width:25 ft. Length:50 ft. Depth:13 ft. Discharge Structure Riser Height:12 ft. Riser Diameter:18 in. Orifice 1 Diameter:0.516 in.Elevation:0 ft. Orifice 2 Diameter:0.750 in.Elevation:8 ft. Element Outlets: Outlet 1 Outlet 2 Outlet Flows To: Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.028 0.000 0.000 0.000 0.1444 0.028 0.004 0.002 0.000 0.2889 0.028 0.008 0.003 0.000 0.4333 0.028 0.012 0.004 0.000 0.5778 0.028 0.016 0.005 0.000 0.7222 0.028 0.020 0.006 0.000 0.8667 0.028 0.024 0.006 0.000 1.0111 0.028 0.029 0.007 0.000 1.1556 0.028 0.033 0.007 0.000 1.3000 0.028 0.037 0.008 0.000 1.4444 0.028 0.041 0.008 0.000 1.5889 0.028 0.045 0.009 0.000 1.7333 0.028 0.049 0.009 0.000 1.8778 0.028 0.053 0.009 0.000 2.0222 0.028 0.058 0.010 0.000 2.1667 0.028 0.062 0.010 0.000 2.3111 0.028 0.066 0.011 0.000 2.4556 0.028 0.070 0.011 0.000 2.6000 0.028 0.074 0.011 0.000 2.7444 0.028 0.078 0.012 0.000 2.8889 0.028 0.082 0.012 0.000 3.0333 0.028 0.087 0.012 0.000 3.1778 0.028 0.091 0.012 0.000 3.3222 0.028 0.095 0.013 0.000 3.4667 0.028 0.099 0.013 0.000 3.6111 0.028 0.103 0.013 0.000 3.7556 0.028 0.107 0.014 0.000 3.9000 0.028 0.111 0.014 0.000 4.0444 0.028 0.116 0.014 0.000 4.1889 0.028 0.120 0.014 0.000 4.3333 0.028 0.124 0.015 0.000 4.4778 0.028 0.128 0.015 0.000 4.6222 0.028 0.132 0.015 0.000 4.7667 0.028 0.136 0.015 0.000 4.9111 0.028 0.140 0.016 0.000 5.0556 0.028 0.145 0.016 0.000 5.2000 0.028 0.149 0.016 0.000 5.3444 0.028 0.153 0.016 0.000 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 9 5.4889 0.028 0.157 0.016 0.000 5.6333 0.028 0.161 0.017 0.000 5.7778 0.028 0.165 0.017 0.000 5.9222 0.028 0.169 0.017 0.000 6.0667 0.028 0.174 0.017 0.000 6.2111 0.028 0.178 0.018 0.000 6.3556 0.028 0.182 0.018 0.000 6.5000 0.028 0.186 0.018 0.000 6.6444 0.028 0.190 0.018 0.000 6.7889 0.028 0.194 0.018 0.000 6.9333 0.028 0.199 0.019 0.000 7.0778 0.028 0.203 0.019 0.000 7.2222 0.028 0.207 0.019 0.000 7.3667 0.028 0.211 0.019 0.000 7.5111 0.028 0.215 0.019 0.000 7.6556 0.028 0.219 0.020 0.000 7.8000 0.028 0.223 0.020 0.000 7.9444 0.028 0.228 0.020 0.000 8.0889 0.028 0.232 0.025 0.000 8.2333 0.028 0.236 0.028 0.000 8.3778 0.028 0.240 0.030 0.000 8.5222 0.028 0.244 0.032 0.000 8.6667 0.028 0.248 0.033 0.000 8.8111 0.028 0.252 0.035 0.000 8.9556 0.028 0.257 0.036 0.000 9.1000 0.028 0.261 0.037 0.000 9.2444 0.028 0.265 0.039 0.000 9.3889 0.028 0.269 0.040 0.000 9.5333 0.028 0.273 0.041 0.000 9.6778 0.028 0.277 0.042 0.000 9.8222 0.028 0.281 0.043 0.000 9.9667 0.028 0.286 0.044 0.000 10.111 0.028 0.290 0.045 0.000 10.256 0.028 0.294 0.046 0.000 10.400 0.028 0.298 0.046 0.000 10.544 0.028 0.302 0.047 0.000 10.689 0.028 0.306 0.048 0.000 10.833 0.028 0.310 0.049 0.000 10.978 0.028 0.315 0.050 0.000 11.122 0.028 0.319 0.051 0.000 11.267 0.028 0.323 0.051 0.000 11.411 0.028 0.327 0.052 0.000 11.556 0.028 0.331 0.053 0.000 11.700 0.028 0.335 0.054 0.000 11.844 0.028 0.339 0.054 0.000 11.989 0.028 0.344 0.055 0.000 12.133 0.028 0.348 0.827 0.000 12.278 0.028 0.352 2.305 0.000 12.422 0.028 0.356 3.929 0.000 12.567 0.028 0.360 5.236 0.000 12.711 0.028 0.364 5.993 0.000 12.856 0.028 0.368 6.614 0.000 13.000 0.028 0.373 7.146 0.000 13.144 0.028 0.377 7.642 0.000 13.289 0.000 0.000 8.106 0.000 Split Basin Model (2025-11-05)11/5/2025 11:20:57 AM Page 10 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.194 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.437 Total Impervious Area:0.685 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.035552 5 year 0.058254 10 year 0.072852 25 year 0.090216 50 year 0.102244 100 year 0.113478 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.020531 5 year 0.031397 10 year 0.040501 25 year 0.054516 50 year 0.067013 100 year 0.081483 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.041 0.015 1950 0.049 0.019 1951 0.078 0.049 1952 0.024 0.014 1953 0.020 0.017 1954 0.030 0.017 1955 0.048 0.017 1956 0.039 0.024 1957 0.031 0.017 1958 0.035 0.018 Split Basin Model (2025-11-05)11/5/2025 11:21:33 AM Page 11 1959 0.030 0.015 1960 0.054 0.043 1961 0.029 0.019 1962 0.018 0.014 1963 0.025 0.018 1964 0.036 0.018 1965 0.024 0.023 1966 0.023 0.017 1967 0.055 0.018 1968 0.031 0.017 1969 0.030 0.016 1970 0.024 0.017 1971 0.027 0.018 1972 0.059 0.041 1973 0.026 0.023 1974 0.029 0.018 1975 0.040 0.016 1976 0.029 0.018 1977 0.004 0.014 1978 0.024 0.019 1979 0.015 0.013 1980 0.069 0.045 1981 0.022 0.017 1982 0.045 0.033 1983 0.039 0.018 1984 0.023 0.015 1985 0.014 0.015 1986 0.061 0.020 1987 0.054 0.038 1988 0.021 0.015 1989 0.014 0.015 1990 0.129 0.044 1991 0.068 0.040 1992 0.028 0.019 1993 0.027 0.014 1994 0.009 0.013 1995 0.039 0.019 1996 0.090 0.049 1997 0.070 0.050 1998 0.017 0.015 1999 0.076 0.040 2000 0.027 0.019 2001 0.005 0.012 2002 0.031 0.026 2003 0.047 0.017 2004 0.050 0.048 2005 0.037 0.018 2006 0.042 0.023 2007 0.097 0.124 2008 0.119 0.048 2009 0.055 0.021 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1287 0.1239 2 0.1186 0.0499 3 0.0973 0.0489 Split Basin Model (2025-11-05)11/5/2025 11:21:33 AM Page 12 4 0.0902 0.0488 5 0.0777 0.0482 6 0.0763 0.0476 7 0.0696 0.0455 8 0.0694 0.0440 9 0.0683 0.0430 10 0.0609 0.0415 11 0.0590 0.0400 12 0.0553 0.0395 13 0.0546 0.0377 14 0.0538 0.0327 15 0.0536 0.0258 16 0.0501 0.0240 17 0.0486 0.0235 18 0.0483 0.0226 19 0.0469 0.0226 20 0.0450 0.0214 21 0.0418 0.0199 22 0.0409 0.0194 23 0.0403 0.0192 24 0.0390 0.0190 25 0.0389 0.0190 26 0.0385 0.0188 27 0.0372 0.0187 28 0.0357 0.0184 29 0.0349 0.0184 30 0.0314 0.0182 31 0.0314 0.0182 32 0.0307 0.0182 33 0.0302 0.0180 34 0.0299 0.0177 35 0.0299 0.0177 36 0.0295 0.0176 37 0.0290 0.0174 38 0.0288 0.0173 39 0.0279 0.0173 40 0.0272 0.0172 41 0.0271 0.0171 42 0.0271 0.0170 43 0.0261 0.0169 44 0.0252 0.0166 45 0.0244 0.0165 46 0.0243 0.0164 47 0.0240 0.0162 48 0.0237 0.0155 49 0.0232 0.0153 50 0.0228 0.0153 51 0.0218 0.0152 52 0.0212 0.0149 53 0.0197 0.0147 54 0.0183 0.0145 55 0.0170 0.0145 56 0.0147 0.0142 57 0.0141 0.0138 58 0.0138 0.0136 59 0.0091 0.0131 60 0.0049 0.0127 61 0.0042 0.0120 Split Basin Model (2025-11-05)11/5/2025 11:21:33 AM Page 14 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0178 17088 17137 100 Pass 0.0186 15498 11935 77 Pass 0.0195 14070 8081 57 Pass 0.0203 12803 4372 34 Pass 0.0212 11569 4145 35 Pass 0.0220 10515 3976 37 Pass 0.0229 9565 3841 40 Pass 0.0237 8757 3743 42 Pass 0.0246 8031 3668 45 Pass 0.0255 7347 3570 48 Pass 0.0263 6737 3437 51 Pass 0.0272 6190 3337 53 Pass 0.0280 5730 3260 56 Pass 0.0289 5309 3163 59 Pass 0.0297 4924 3048 61 Pass 0.0306 4569 2928 64 Pass 0.0314 4237 2815 66 Pass 0.0323 3951 2691 68 Pass 0.0331 3643 2556 70 Pass 0.0340 3390 2428 71 Pass 0.0348 3133 2271 72 Pass 0.0357 2915 2120 72 Pass 0.0365 2706 1959 72 Pass 0.0374 2490 1790 71 Pass 0.0383 2314 1617 69 Pass 0.0391 2136 1433 67 Pass 0.0400 1973 1281 64 Pass 0.0408 1824 1170 64 Pass 0.0417 1702 1061 62 Pass 0.0425 1577 970 61 Pass 0.0434 1442 840 58 Pass 0.0442 1325 727 54 Pass 0.0451 1232 643 52 Pass 0.0459 1147 514 44 Pass 0.0468 1085 399 36 Pass 0.0476 1020 264 25 Pass 0.0485 947 198 20 Pass 0.0493 886 150 16 Pass 0.0502 824 131 15 Pass 0.0511 760 124 16 Pass 0.0519 725 116 16 Pass 0.0528 674 108 16 Pass 0.0536 623 87 13 Pass 0.0545 589 52 8 Pass 0.0553 549 34 6 Pass 0.0562 506 25 4 Pass 0.0570 469 24 5 Pass 0.0579 427 23 5 Pass 0.0587 388 23 5 Pass 0.0596 356 23 6 Pass 0.0604 328 20 6 Pass 0.0613 298 20 6 Pass 0.0621 270 20 7 Pass Split Basin Model (2025-11-05)11/5/2025 11:21:33 AM Page 15 0.0630 241 17 7 Pass 0.0638 218 16 7 Pass 0.0647 197 15 7 Pass 0.0656 173 15 8 Pass 0.0664 152 13 8 Pass 0.0673 130 13 10 Pass 0.0681 119 13 10 Pass 0.0690 104 13 12 Pass 0.0698 95 13 13 Pass 0.0707 83 12 14 Pass 0.0715 74 12 16 Pass 0.0724 69 12 17 Pass 0.0732 61 10 16 Pass 0.0741 53 9 16 Pass 0.0749 46 9 19 Pass 0.0758 39 8 20 Pass 0.0766 29 8 27 Pass 0.0775 25 7 28 Pass 0.0784 22 7 31 Pass 0.0792 20 7 35 Pass 0.0801 17 7 41 Pass 0.0809 14 7 50 Pass 0.0818 12 7 58 Pass 0.0826 8 7 87 Pass 0.0835 7 7 100 Pass 0.0843 7 7 100 Pass 0.0852 7 6 85 Pass 0.0860 6 5 83 Pass 0.0869 6 5 83 Pass 0.0877 6 5 83 Pass 0.0886 6 5 83 Pass 0.0894 6 4 66 Pass 0.0903 5 4 80 Pass 0.0912 5 4 80 Pass 0.0920 5 4 80 Pass 0.0929 5 4 80 Pass 0.0937 5 4 80 Pass 0.0946 5 3 60 Pass 0.0954 5 3 60 Pass 0.0963 4 3 75 Pass 0.0971 4 3 75 Pass 0.0980 3 3 100 Pass 0.0988 3 2 66 Pass 0.0997 3 2 66 Pass 0.1005 3 2 66 Pass 0.1014 3 2 66 Pass 0.1022 3 2 66 Pass Split Basin Model (2025-11-05)11/5/2025 11:21:33 AM Page 17 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.046 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.012 Total Impervious Area:0.106 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.00137 5 year 0.002244 10 year 0.002807 25 year 0.003476 50 year 0.003939 100 year 0.004372 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.046118 5 year 0.058907 10 year 0.067852 25 year 0.079724 50 year 0.088996 100 year 0.098646 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.002 0.060 1950 0.002 0.061 1951 0.003 0.036 1952 0.001 0.030 1953 0.001 0.036 1954 0.001 0.037 1955 0.002 0.044 1956 0.001 0.040 1957 0.001 0.045 1958 0.001 0.038 1959 0.001 0.041 Split Basin Model (2025-11-05)11/5/2025 11:22:12 AM Page 18 1960 0.002 0.040 1961 0.001 0.039 1962 0.001 0.034 1963 0.001 0.040 1964 0.001 0.040 1965 0.001 0.046 1966 0.001 0.033 1967 0.002 0.054 1968 0.001 0.070 1969 0.001 0.042 1970 0.001 0.043 1971 0.001 0.052 1972 0.002 0.051 1973 0.001 0.033 1974 0.001 0.048 1975 0.002 0.051 1976 0.001 0.039 1977 0.000 0.038 1978 0.001 0.055 1979 0.001 0.068 1980 0.003 0.070 1981 0.001 0.045 1982 0.002 0.065 1983 0.001 0.053 1984 0.001 0.034 1985 0.001 0.043 1986 0.002 0.039 1987 0.002 0.060 1988 0.001 0.038 1989 0.001 0.060 1990 0.005 0.079 1991 0.003 0.067 1992 0.001 0.034 1993 0.001 0.040 1994 0.000 0.036 1995 0.002 0.041 1996 0.003 0.052 1997 0.003 0.042 1998 0.001 0.043 1999 0.003 0.094 2000 0.001 0.044 2001 0.000 0.053 2002 0.001 0.055 2003 0.002 0.054 2004 0.002 0.090 2005 0.001 0.036 2006 0.002 0.034 2007 0.004 0.085 2008 0.005 0.063 2009 0.002 0.064 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0050 0.0938 2 0.0046 0.0904 3 0.0037 0.0851 4 0.0035 0.0786 Split Basin Model (2025-11-05)11/5/2025 11:22:12 AM Page 19 5 0.0030 0.0703 6 0.0029 0.0700 7 0.0027 0.0675 8 0.0027 0.0672 9 0.0026 0.0651 10 0.0023 0.0639 11 0.0023 0.0628 12 0.0021 0.0614 13 0.0021 0.0603 14 0.0021 0.0599 15 0.0021 0.0597 16 0.0019 0.0549 17 0.0019 0.0547 18 0.0019 0.0542 19 0.0018 0.0542 20 0.0017 0.0530 21 0.0016 0.0526 22 0.0016 0.0517 23 0.0016 0.0515 24 0.0015 0.0514 25 0.0015 0.0509 26 0.0015 0.0482 27 0.0014 0.0458 28 0.0014 0.0452 29 0.0013 0.0448 30 0.0012 0.0441 31 0.0012 0.0436 32 0.0012 0.0435 33 0.0012 0.0435 34 0.0012 0.0426 35 0.0012 0.0420 36 0.0011 0.0419 37 0.0011 0.0409 38 0.0011 0.0408 39 0.0011 0.0404 40 0.0010 0.0403 41 0.0010 0.0403 42 0.0010 0.0402 43 0.0010 0.0395 44 0.0010 0.0387 45 0.0009 0.0386 46 0.0009 0.0385 47 0.0009 0.0382 48 0.0009 0.0378 49 0.0009 0.0376 50 0.0009 0.0369 51 0.0008 0.0361 52 0.0008 0.0359 53 0.0008 0.0359 54 0.0007 0.0359 55 0.0007 0.0339 56 0.0006 0.0337 57 0.0005 0.0336 58 0.0005 0.0335 59 0.0004 0.0330 60 0.0002 0.0327 61 0.0002 0.0296 Split Basin Model (2025-11-05)11/5/2025 11:22:12 AM Page 24 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. Split Basin Model (2025-11-05)11/5/2025 11:22:13 AM Page 25 Appendix Predeveloped Schematic Split Basin Model (2025-11-05)11/5/2025 11:22:14 AM Page 26 Mitigated Schematic