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Civil Engineering & Development Services 1700 NW Gilman Blvd., Suite 200; Issaquah, WA 98027 (425) 821-5038 TECHNICAL INFORMATION REPORT CITY OF RENTON For Varma SFR 13014 156th Ave SE Renton, WA 98059 June 13, 2025 Prepared For: Kushal Varma 1518 Jericho Place NE Renton, WA 98059 Stormwater Technical Information Report For Full Drainage Review Project Sites Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page i Project Name: Varma 3 Lot Short Plat Project Address: 13012 156th Ave SE Renton, WA 98059 Parcel Number(s): 366450-0185 Name of Developer/Owner: Kushal Varma Name of Engineer: Edward Mecum, PE Company: G2 Civil Address: 1700 NW Gilman Blvd., Ste. 200, Issaquah, WA 98027 Phone Number: 425-821-5038 Report Date: June 13, 2025 Engineer’s Stamp: This box to be completed by COK staff PERMIT # Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page ii Table of Contents I. PROJECT OVERVIEW .............................................................................................................. 1 II. CONDITIONS AND REQUIREMENTS SUMMARY ..................................................................... 6 III. DOWNSTREAM ANALYSIS .................................................................................................... 10 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................... 13 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN .................................................................... 15 VI. SPECIAL REPORTS AND STUDIES .......................................................................................... 15 VII. OTHER PERMITS ................................................................................................................... 15 VIII. CSWPP ANALYSIS AND DESIGN ............................................................................................ 15 IX. BOND QUANTITIES, FACILITY SUMMARIES & DECLARATION of COVENANT ........................ 16 List of Figures Figure 1 – Vicinity Map Figure 2 – Soils Map and Legend Figure 3 – Existing Conditions Map Figure 4 – Developed Conditions Map Figure 5 – Drainage Review Flow Chart Figure 6 – Downstream Map 1 Figure 7 – Downstream Map 2 Appendix A Wetland and Stream Reconnaissance for 13016- 156th Avenue SE, Renton WA by Altmann Oliver Associates, LLC dated January 29, 2020 Appendix B Infiltration Assessment by The Riley Group, Inc. dated September 2, 2020 Geotechnical Engineering Report by The Riley Group, Inc. dated November 10, 2022 Appendix C WWHM Output Appendix D Operations and Maintenance Manual Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 1 I. PROJECT OVERVIEW Project: Varma SFR Site Address: 13014 156th Ave SE Tax Parcel #: 3664500185 Zoning District: R-4, Residential Site Area: Total Lot Area = 5,872 SF (1.05 Acres) Site Location: The site is in the City of Renton within the NW ¼ of the NE ¼ of Section 14, Township 23 North, Range 5 East, W.M, King County, Washington. Figure 1: Vicinity Map SITE Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 2 Pre-developed Site Conditions The project site is within the City of Renton. The site is accessed from 156th Ave SE, approximately 250 feet north of the intersection of SE 132nd St and 156th Ave SE. The site is bordered to the north, south and east by single-family residences, and to the west 156th Ave SE. The project site currently consists of an existing single family residence with a driveway and associated walks and patio areas. The house was permitted and completed in 2024 with all impervious surfaces mitigated for stormwater runoff. The site is gently sloped to the from the north to the south at a slope of 2% and has a slight ridge from the northwest corner toward the middle of the south property line. The property is located within the Lower Cedar River drainage basin. Runoff from the site is divided into two separate flow paths that follow 156th and 158th Avenues. See full downstream analysis in Section III. Critical Areas According to COR Maps, and the Wetland and Stream Reconnaissance dated January 29, 2020 (Appendix A), no critical areas are located on the project site. Soils Per the US Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS) information, the entire project site is underlain with Alderwood gravelly sandy loam, 8 to 15 percent slopes (See Figure 3 on the following page). Soils encountered in on- site investigations include medium dense silty sand with gravel over very dense glacial till per the Geotechnical Engineering Report prepared by The Riley Group, Inc. (Appendix B). Developed Site Conditions The proposed project will divide the existing parcel into three single family lots, retaining the existing residence. An access and utilities tract will provide service to each of the new lots from 156th Ave SE along the north property line. Each new lot will meet or exceed the area required to meet zoning requirements. Site runoff will be mitigated via dispersion to mimic the existing drainage patterns within the two previously defined, on-site drainage basins. Since the frontage improvements were installed during the construction of the existing residence, only utility work within the Right of Way is proposed, which will not result in additional impervious surfaces. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 3 Figure 2: Soil Map and Legend SITE Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 4 EAST BASIN Figure 3: Existing Conditions Map N Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 5 Figure 4: Developed Conditions Map Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 6 II. CONDITIONS AND REQUIREMENTS SUMMARY The 2017 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 1.1.2.3 of the RSWDM, the project must meet all nine (9) core and all six (6) special requirements. However, unlike Full Drainage Review, not all items must be documented by a Licensed Civil Engineer. See Figure 5 below for more information on how the type of drainage review was determined. Figure 5: Drainage Review Flow Chart Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 7 Core Requirements Core Requirement #1: Discharge at the Natural Location The proposed development will follow existing drainage patterns in to both basins. Refer to the Level 1 Downstream Analysis in Section III of this TIR for a complete description of the existing drainage paths. 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 The project is exempt from flow control based on the modeled increase in stormwater runoff. The increased runoff from the proposed project does not exceed the permissible increased runoff rate without providing flow control measures. See Section IV. Core Requirement #4: Conveyance System The proposed on-site conveyance system, dispersion and grading will route runoff to the natural discharge point. Please refer to Section V for the conveyance system analysis. 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 and in the separate CSWPPP that addresses the required 13 sections. 1. Clearing Limits 2. Cover Measures 3. Perimeter Protection 4. Traffic Area Stabilization 5. Sediment Retention 6. Surface Water Collection 7. Dewatering Control 8. Dust Control 9. Flow Control 10. Control Pollutants 11. Protect Existing and Proposed Stormwater Facilities and On-site BMPs 12. Maintain Protective BMPs 13. Manage the Project Core Requirement #6: Maintenance and Operations An Operation and Maintenance Manual will be provided in Appendix D upon review and acceptance of the drainage design. 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 The proposed pollution-generating impervious surface (PGIS) is less than the 5,000 SF threshold for both basins, West and East is 3,097 SF & 2,898 SF respectively; therefore water quality is not required. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 8 Core Requirement #9: Flow Control BMPs This project is classified as a Single-Family Residence and is subject to the Large Lot BMP Requirements detailed in Section 1.2.9.2.2 in the RSWDM. Full dispersion is not available due to the NGRA requirement and the required 100-foot native vegetated flow-path segment is not available. The impervious coverage is less than 45% and BMPs are proposed for all of the target impervious surfaces which satisfies the Large Lot BMP requirements. Impervious Surface BMP Evaluation Full Dispersion: Infeasible. The space required for a 100-foot native vegetated flow-path segment is not available downstream of the target surfaces and the parcel could not support the NGRA requirement. Full Infiltration: Infeasible. The Geotechnical Engineering Report prepared by The Riley Group, Inc. dated November 10, 2022 (Appendix B) states that infiltration is infeasible at the site due to underlain glacial till and confirmed by an in-situ infiltration test. Limited Infiltration: Infeasible. BMP’s relying on infiltration are not feasible as described above. Rain Gardens/Bioretention: Infeasible. BMP’s relying on infiltration are not feasible as described above. Permeable Pavement: Infeasible. BMP’s relying on infiltration are not feasible as described above. Basic Dispersion: FEASIBLE. Sheet flow dispersion from the access road is proposed for the common driveway area. Each future residence will incorporate basic dispersion trenches sized to mitigate the additional impervious surface created by those construction projects. Reduced Impervious Surface Credit: Infeasible. All impervious surfaces have been mitigated with a higher value BMP. Native Growth Retention Credit: Infeasible. All impervious surfaces have been mitigated with a higher value BMP. Tree Retention Credit: Infeasible. All impervious surfaces have been mitigated with a higher value BMP. Soil Amendment: Feasible. All disturbed, pervious areas of the project will meet soil amendment requirements as detailed in Section C.2.13 of the RSWDM. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 9 Special Requirements Special Requirement #1: Other Adopted Area-Specific Requirements Master Drainage Plans– N/A Basin Plan – N/A Salmon Conservation Plans- N/A Lake Management Plans – N/A Hazard Mitigation Plan- N/A Shared Facility Drainage Plans – 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 The project is not a commercial building or development; therefore, this requirement is 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. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 10 III. DOWNSTREAM ANALYSIS A Level 1 Offsite Analysis has been performed for the project site per Section 1.2.2.1 of the 2017 City of Renton Surface Water Design Manual by an engineer under my supervision on Wednesday June 10, 2020. The analysis was performed at approximately 3:30 PM with a temperature of about 75°. Soil conditions were observed to be saturated. The property is currently undeveloped and has been partially cleared by previous development to the north. The site is contained within a single drainage basin, the Lower Cedar River, but discharges from two separate locations. The two flow paths do not converge within ¼ mile downstream of the site, and therefore two Level 1 downstream analyses are required for this project. A map showing the study area is included see Figures 6 & 7 on the following pages. We have reviewed the site and the applicable resources for both listed and potential problems. The receiving waterbody, Lower Cedar River, is impaired at a Category 5 – 303d level for pH, Temperature, and Dissolved Oxygen per the Washington Department of Ecology Water Quality Atlas. No other critical areas or critical area buffers were located on the site per King County iMap, the City of Renton GIS maps, FEMA maps, or the CED Wetlands Inventory. The site is divided into two drainage basins with a total area of 1.07 acres which does not include the frontage improvements. An approximate “basin line” has been added to the downstream map to reflect this information. The western basin directs stormwater runoff west towards the 156th Avenue SE system as detailed below. The eastern basin directs stormwater runoff south and east towards the 158th Avenue SE system as detailed below. The eastern basin will remain undeveloped. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 11 Figure 6: Downstream Map 1 Figure 7: Downstream Map 2 WEST EAST MATCHLINE APPROXIMATE BASIN LINE Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 12 East Basin The Eastern Drainage basin, detailed in this Analysis, is approximately 0.76 acres in size. Slopes range from 1-4% across the site. The study area for this analysis extends downstream for approximately one quarter mile and includes no upstream offsite drainage area tributary to the project site. The neighboring property to the north, while located at a higher elevation, has been previously developed and does not direct significant stormwater runoff to the subject property. Stormwater runoff from the eastern basin sheet flows to the south and east across the property line where it enters a stormwater ditch along the west side of 158th Ave SE. This ditch conveys flows south along 158th Ave SE through a series of culverts for driveway access. Runoff is then directed into sections of 12” Polyethylene culverts which convey stormwater under NE 1st St. The 158th Ave SE system collects runoff via catch basins within the public right-of-way as well as tie- ins from other residential development. The 12” Polyethylene pipe discharges to a series of stormwater ditches which are interrupted by 12” Polyethylene culverts and a 12” Concrete culvert for conveyance under driveway accesses. Stormwater is then directed into the SE 2nd Pl system which ultimately discharges runoff into the Lower Cedar River and the Lake Washington watershed. This Analysis was ended at a point over ¼ mile downstream of the site discharge location. West Basin The Western Drainage basin, detailed in this Analysis, is approximately 0.31 acres in size. Slopes range from 1-4% across the site. The study area for this analysis extends downstream for approximately one quarter mile and includes no upstream offsite drainage area tributary to the project site. The neighboring property to the north, while located at a higher elevation, has been previously developed and does not direct significant stormwater runoff to the subject property. Stormwater runoff from the western basin sheet flows to the south and west across the property line where it enters a stormwater ditch along the east side of 156th Ave SE. This ditch conveys flows south along 156th Ave SE through a series of culverts for driveway access. Runoff is then directed into a 12” Concrete culvert which marks the beginning of the 156th Ave SE closed conveyance system. This continues to direct flows south into a section of 12” Ductile Iron pipe which transitions to 12” Polyethylene pipe. This system collects runoff via catch basins within the public right-of-way as well as tie-ins from other residential development. The 12” Polyethylene pipe continues to convey stormwater south, and ultimately discharges runoff into the Lower Cedar River and the Lake Washington watershed. This Analysis was ended at a point over ¼ mile downstream of the site discharge location. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 13 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN The site was analyzed using the Western Washington Hydrology Model (WWHM) provided by the Department of Ecology (DOE). We are only modeling the portion of the site that’s being developed. The project site is in a Level 2 Flow Control Area, therefore forested conditions have been used for the pre-developed modeling analysis. The hydrologic analysis of the site was completed to determine the increase in 100-year peak. Per Section 1.2.3.1.A, a formal flow control facility is waived for any threshold discharge area in which the target surfaces will generate no more than a 0.10 CFS increase (utilizing hourly timesteps) in the existing site conditions 100-year peak flow. All pervious areas are modeled as “pasture” due to reflect the soil amendment that will be installed. The WWHM analysis concluded that the increase in the 100- year peak is less than 0.10 CFS for both basins, therefore a formal flow control facility is not required. Given the topography of the existing project site, the West & East Basins were analyzed for the project. The site basin criterion is summarized below. Refer to Appendix A for the complete WWHM analysis. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 14 WEST BASIN FLOW RATES: Pre-Dev. Developed EAST BASIN FLOW RATES: Pre-Dev. Developed West Basin: Q dev–Q predev = 0.0831 CFS – 0.0238 CFS = 0.0593 CFS East Basin: Q dev–Q predev = 0.131 CFS – 0.047 CFS = 0.084 CFS Therefore, both basins meet basic exemption, as noted in the analysis. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 15 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN The runoff from the proposed on-site storm drainage does not warrant a conveyance system analysis all runoff associated with the subdivision will sheet flow for basic dispersion. The frontage improvements have been completed under the construction of the single family and addressed offsite flow rates. Any piped storm conveyance associated with the future single family residences will be assessed during the drainage review of those projects. VI. SPECIAL REPORTS AND STUDIES • Infiltration Assessment by The Riley Group, Inc. dated September 2, 2020 • Geotechnical Engineering Report by The Riley Group, Inc. dated November 10, 2022 • Wetland and Stream Reconnaissance for 13016- 156th Ave. SE Renton WA by Altmann Oliver Associates, LLC, dated January 29, 2020. VII. OTHER PERMITS • Civil Construction Permit • Final Short Plat • Building Permits • Right-of-Way Use Permit • WD 90 Water Service Application VIII. CSWPP ANALYSIS AND DESIGN Erosion/Sedimentation Control Design: Several standard Best Management Practices (BMP’s) per CORSWDM Appendix D.3 will be utilized by the contractor to minimize the amount of erosion and sedimentation that may be perpetuated by the construction of the site. The thirteen erosion and sedimentation control measures are outlined below: Clearing Limits- Prior to any site clearing, the areas to remain undisturbed during the project construction shall be physically marked on the project site. The clearing limits are delineated on the TESC Plan as the area to be disturbed. Cover Measures- Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas. Materials will be stockpiled on-site and will be covered with plastic sheeting per City of Renton SWDM D.2.1.2.4 when necessary. Perimeter Protection- Filter fencing per City of Renton SWDM D.2.1.3.1 shall be used downstream of all disturbed areas to filter sediment from sheet flow. Varma Renton 3 Lot Short Plat Technical Information Report June 13, 2025 Page 16 Traffic Area Stabilization- A stabilized construction entrance per City of Renton SWDM D.2.1.4.1 shall be implemented. Sediment Retention- Given the small scope of work and minimal grading, the installation of a filter fence will provide adequate means of trapping sediment on-site. If sediment is tracked off-site, public roads shall be cleaned thoroughly at the end of each day or more frequently during wet weather, per CORSWDM Section D.3.2.B.2. Surface Water Collection- Given the small scope of work and minimal grading, runoff can be treated solely with the filter fence used for perimeter protection. There are no significant sources of upstream surface water that drain onto the disturbed areas. Dewatering Control- Dewatering is not anticipated. Dust Control- Dust control is not anticipated to be required but shall be implemented per City of Renton SWDM Table D.2.1.8.A when necessary. Flow Control- Given the scope of the project additional flow control measures are not warranted during construction. Control Pollutants- No pollutants will be stored onsite, but a spill kit shall be retained onsite in case of any fuel spills from construction equipment. Protect Existing and Proposed Flow Control BMPs- The location of the proposed perforated stub out connection shall be protected from compaction/ sedimentation during project construction. Maintain BMPs- TESC BMPs shall be maintained and repaired as needed throughout construction. All disturbed areas of the project site shall be vegetated or otherwise permanently stabilized once completed. Manage the Project- The TESC plan shall be retained onsite anytime construction work is taking place. Prior to commencing construction, a TESC contact will be established. IX. BOND QUANTITIES, FACILITY SUMMARIES & DECLARATION of COVENANT The Bond Quantities (BQWS) and Declaration of Covenant are included in this section. A Facility Summary is not required for this project. Varma Renton 3 Lot Short Plat Technical Information Report Appendix A Wetland and Stream Reconnaissance for 13016- 156th Ave. SE Renton WA by Altmann Oliver Associates, LLC, dated January 29, 2020 January 29, 2020 AOA-6125 Dan Finkbeiner danfinkbeiner@comcast.net SUBJECT: Wetland and Stream Reconnaissance for 13016 – 156th Ave. SE Renton, WA (Parcels 366450-0185 an -0205) Dear Dan: On January 21, 2020 I conducted a wetland and stream reconnaissance on the subject property utilizing the methodology outlined in the May 2010 Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0). No wetlands or streams were identified on or adjacent to the property during the field investigation. The western portion of the site on Parcel 366450-0205 is currently developed with a single-family residence and associated yard. The remainder of this parcel is undeveloped and consisted of a mixed upland forest and brush patches that included Douglas fir (Pseudotsuga menziesii), western red cedar (Thuja plicata), Himalayan blackberry (Rubus armeniacus), English holly (Ilex aquilinum), sword fern (Polystichum munitum), and English ivy (Hedera helix). Parcel 366450-0185 consisted primarily of upland pasture and fill areas. Common plant species were generally typical of disturbed more mesic environments and included a variety of grasses, cats ear (Hypochaeris radicata), English plantain (Plantago lanceolata), and oxeye daisy (Chrysanthemum leucanthemum). No hydrophytic plant communities were observed on or adjacent to the property. Borings taken throughout the site revealed high chroma non-hydric soils and there was no evidence of ponding or prolonged soil saturation anywhere in the vicinity of the property. Dan Finkbeiner January 29, 2020 Page 2 Conclusion No wetlands or streams were identified on or immediately adjacent the site. This determination is based on a field investigation during which no hydrophytic plant communities, hydric soils, or evidence of wetland hydrology or channels were observed. If you have any questions regarding the reconnaissance, please give me a call. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC John Altmann Ecologist Pictometry, King County, King County King County iMap Date: 1/29/2020 Notes: The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness,or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County.± Varma Renton 3 Lot Short Plat Technical Information Report Appendix B Infiltration Assessment by The Riley Group, Inc. dated September 2, 2020 Geotechnical Engineering Report by The Riley Group, Inc. dated November 10, 2022 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 ♦ Fax 425.415.0311 www.riley-group.com GEOTECHNICAL ENGINEERING REPORT PREPARED BY: THE RILEY GROUP, INC. 17522 BOTHELL WAY NORTHEAST BOTHELL, WASHINGTON 98011 PREPARED FOR: KUSHAL VARMA 4159 NORTHWEST WOODGATE AVENUE PORTLAND, OREGON 97229 RGI PROJECT NO. 2020-317-1 VARMA 3-LOT SHORT PLAT 13014 156TH AVENUE SOUTHEAST RENTON, WASHINGTON 98059 APRIL 8, 2025 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 ♦ Fax 425.415.0311 www.riley-group.com April 8, 2025 Kushal Varma 4159 Northwest Woodgate Avenue Portland, Washington 97229 Subject: Geotechnical Engineering Report Varma 3-Lot Short Plat 13014 156th Avenue Southeast Renton, Washington RGI Project No. 2020-317-1 Dear Mr. Varma: As requested, The Riley Group, Inc. (RGI) has performed a Geotechnical Engineering Report (GER) for the Varma 3-Lot Plat located at 13014 156th Avenue Southeast, Renton, Washington. Our services were completed in accordance with our proposal 2020-317-PRP1 dated August 3, 2020. The information in this GER is based on our understanding of the proposed construction, and the soil and groundwater conditions encountered in the test pits and hand augers completed by RGI at the site on August 24, 2020. RGI recommends that you submit the project plans and specifications to RGI for a general review so that we may confirm that the recommendations in this GER are interpreted and implemented properly in the construction documents. RGI also recommends that a representative of our firm be present on site during portions of the project construction to confirm that the soil and groundwater conditions are consistent with those that form the basis for the engineering recommendations in this GER. If you have any questions or require additional information, please contact us. Respectfully submitted, THE RILEY GROUP, INC. 04/08/2025 Collin McCracken, PE, LG Senior Geotechnical Engineer Geotechnical Engineering Report i April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 TABLE OF CONTENTS 1.0 INTRODUCTION ............................................................................................................................... 1 2.0 PROJECT DESCRIPTION ............................................................................................................... 1 3.0 FIELD EXPLORATION AND LABORATORY TESTING .......................................................... 1 3.1 FIELD EXPLORATION ................................................................................................................................... 1 3.2 LABORATORY TESTING ................................................................................................................................ 2 4.0 SITE CONDITIONS ........................................................................................................................... 2 4.1 SURFACE .................................................................................................................................................. 2 4.2 GEOLOGY ................................................................................................................................................. 2 4.3 SOILS ....................................................................................................................................................... 2 4.4 GROUNDWATER ........................................................................................................................................ 2 4.5 SEISMIC CONSIDERATIONS ........................................................................................................................... 3 4.6 GEOLOGIC HAZARD AREAS .......................................................................................................................... 4 5.0 DISCUSSION AND RECOMMENDATIONS ................................................................................. 4 5.1 GEOTECHNICAL CONSIDERATIONS ................................................................................................................. 4 5.2 EARTHWORK ............................................................................................................................................. 4 5.2.1 Erosion and Sediment Control ..................................................................................................... 4 5.2.2 Stripping and Subgrade Preparation ............................................................................................ 5 5.2.3 Excavations .................................................................................................................................. 5 5.2.4 Structural Fill ................................................................................................................................ 6 5.2.5 Wet Weather Construction Considerations ................................................................................. 7 5.3 FOUNDATIONS .......................................................................................................................................... 8 5.4 RETAINING WALLS ..................................................................................................................................... 9 5.5 SLAB-ON-GRADE CONSTRUCTION ................................................................................................................. 9 5.6 DRAINAGE .............................................................................................................................................. 10 5.6.1 Surface ....................................................................................................................................... 10 5.6.2 Subsurface .................................................................................................................................. 10 5.6.3 Infiltration .................................................................................................................................. 10 5.7 UTILITIES ................................................................................................................................................ 10 6.0 ADDITIONAL SERVICES .............................................................................................................. 11 7.0 LIMITATIONS ................................................................................................................................. 11 LIST OF FIGURES AND APPENDICES Figure 1 ..................................................................................................................... Site Vicinity Map Figure 2 ............................................................................................... Geotechnical Exploration Plan Figure 3 ............................................................................................... Retaining Wall Drainage Detail Figure 4 ................................................................................................... Typical Footing Drain Detail Appendix A .......................................................................... Field Exploration and Laboratory Testing Geotechnical Engineering Report ii April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 Executive Summary This Executive Summary should be used in conjunction with the entire Geotechnical Engineering Report (GER) for design and/or construction purposes. It should be recognized that specific details were not included or fully developed in this section, and the GER must be read in its entirety for a comprehensive understanding of the items contained herein. Section 7.0 should be read for an understanding of limitations. RGI’s geotechnical scope of work included the advancement of 2 test pits to approximate depths of 4.5 feet below existing site grades. Based on the information obtained from our subsurface exploration, the site is suitable for development of the proposed project. The following geotechnical considerations were identified: Soil Conditions: The soils encountered during field exploration include medium dense silty sand with gravel over very dense glacial till. Groundwater: No groundwater seepage was encountered during our subsurface exploration. Foundations: Foundations for the proposed residences may be supported on conventional spread footings bearing on medium dense to dense native soil or structural fill. Slab-on-grade: Slab-on-grade floors and slabs for the proposed residences can be supported on medium dense to dense native soil or structural fill. Geotechnical Engineering Report 1 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 1.0 Introduction This Geotechnical Engineering Report (GER) presents the results of the geotechnical engineering services provided for the Varma 3-Lot Plat in Renton, Washington. The purpose of this evaluation is to assess subsurface conditions and provide geotechnical recommendations for the construction of a 3-Lot Plat. Our scope of services included field explorations, laboratory testing, engineering analyses, and preparation of this GER. The recommendations in the following sections of this GER are based upon our current understanding of the proposed site development as outlined below. If actual features vary or changes are made, RGI should review them in order to modify our recommendations as required. In addition, RGI requests to review the site grading plan, final design drawings and specifications when available to verify that our project understanding is correct and that our recommendations have been properly interpreted and incorporated into the project design and construction. 2.0 Project description The project site is located at 13014 156th Avenue Southeast in Renton, Washington. The approximate location of the site is shown on Figure 1. The site is currently undeveloped. RGI understands that it is proposed to construct a 3-Lot Plat on the site. At the time of preparing this GER, building plans were not available for our review. Based on our experience with similar construction, RGI anticipates that the proposed building will be supported on perimeter walls with bearing loads of two to six kips per linear foot, and a series of columns with a maximum load up to 30 kips. Slab-on-grade floor loading of 250 pounds per square foot (psf) are expected. 3.0 Field Exploration and Laboratory Testing 3.1 FIELD EXPLORATION On August 24, 2020, RGI observed the excavation of 2 test pits. The approximate exploration locations are shown on Figure 2. Field logs of each exploration were prepared by the geologist that continuously observed the excavations. These logs included visual classifications of the materials encountered during excavation as well as our interpretation of the subsurface conditions between samples. The test pits and hand augers logs included in Appendix A represent an interpretation of the field logs and include modifications based on laboratory observation and analysis of the samples. Geotechnical Engineering Report 2 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 3.2 LABORATORY TESTING During the field exploration, a representative portion of each recovered sample was sealed in containers and transported to our laboratory for further visual and laboratory examination. Selected samples retrieved from the test pits were tested for moisture content and grain size analysis to aid in soil classification and provide input for the recommendations provided in this GER. The results and descriptions of the laboratory tests are enclosed in Appendix A. 4.0 Site Conditions 4.1 SURFACE The subject site consists of King County Tax Parcel number 3664500185, and is 1.07 acres in size. The site is bounded to the north, south, and east by residential properties, and to the west by 156th Avenue Southeast. The existing site is undeveloped land covered by scattered trees and other vegetation. The site is relatively flat with an overall elevation difference of approximately 5 feet. 4.2 GEOLOGY Review of the Geologic map of the Renton quadrangle, King County, Washington by Mullineaux, 1965 indicates that the soil in the project vicinity is mapped as Vashon-age lodgment till (Qvt). Lodgment till consists of a non-sorted mixture of silt, sand, gravel, cobbles, and boulders which looks like concrete mix. Till is very dense from compaction of glacial ice and is considered a restrictive layer in stormwater planning. Drainage does occur in the upper several feet of the till deposits, but water ponds and moves laterally along the underlying unweathered till surface. These descriptions are generally similar to our observations in the field. 4.3 SOILS The soils encountered during field exploration include medium dense silty sand with gravel over very dense glacial till. More detailed descriptions of the subsurface conditions encountered are presented in the test pits and hand augers included in Appendix A. Sieve analysis was performed on two selected soil samples. Grain size distribution curves are included in Appendix A. 4.4 GROUNDWATER No groundwater seepage was encountered during our subsurface exploration. Evidence of high groundwater (mottling) was observed in the silty sand overlying the lodgment till in some of the explorations. Geotechnical Engineering Report 3 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 It should be recognized that fluctuations of the groundwater table will occur due to seasonal variations in the amount of rainfall, runoff, and other factors not evident at the time the explorations were performed. In addition, perched water can develop within seams and layers contained in fill soils or higher permeability soils overlying less permeable soils following periods of heavy or prolonged precipitation. Therefore, groundwater levels during construction or at other times in the future may be higher or lower than the levels indicated on the logs. 4.5 SEISMIC CONSIDERATIONS Based on the International Building Code (IBC), RGI recommends the follow seismic parameters for design. Table 1 IBC Parameter Value Site Soil Class1 C2 Short Period Spectral Response Acceleration, SS (g) 1.372 1-Second Period Spectral Response Acceleration, S1 (g) 0.470 1. Note: In general accordance with Chapter 20 of ASCE 7-16. The Site Class is based on the average characteristics of the upper 100 feet of the subsurface profile. 2. Note: ASCE 7-16 require a site soil profile determination extending to a depth of 100 feet for seismic site classification. The current scope of our services does not include the required 100 foot soil profile determination. Hand augers extended to a maximum depth of 4 feet, and this seismic site class definition considers that similar soil continues below the maximum depth of the subsurface exploration. Additional exploration to deeper depths would be required to confirm the conditions below the current depth of exploration. 3. Note: In accordance with ASCE 11.4.8, a ground motion hazard analysis is not required for the following cases: • Structures on Site Class E sites with SS greater than or equal to 1.0, provided the site coefficient Fa is taken as equal to that of Site Class C. • Structures on Site Class D sites with S1 greater than or equal to 0.2, provided that the value of the seismic response coefficient Cs is determined by Eq. 12.8-2 for values of T ≤ 1.5Ts and taken as equal to 1.5 times the value computed in accordance with either Eq. 12.8-3 for TL ≥ T > 1.5Ts or Eq. 12.8-4 for T > TL. • Structures on Site Class E sites with S1 greater than or equal to 0.2, provided that T is less than or equal to Ts and the equivalent static force procedure is used for design. The above exceptions do not apply to seismically isolated structures, structures with damping systems or structures designed using the response history procedures of Chapter 16. Liquefaction is a phenomenon where there is a reduction or complete loss of soil strength due to an increase in water pressure induced by vibrations from a seismic event. Liquefaction mainly affects geologically recent deposits of fine-grained sands that are below the groundwater table. Soils of this nature derive their strength from intergranular friction. The generated water pressure or pore pressure essentially separates the soil grains and eliminates this intergranular friction, thus reducing or eliminating the soil’s strength. RGI reviewed the results of the field and laboratory testing and assessed the potential for liquefaction of the site’s soil during an earthquake. Since the site is underlain by glacial till, RGI considers that the possibility of liquefaction during an earthquake is minimal. Geotechnical Engineering Report 4 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 4.6 GEOLOGIC HAZARD AREAS Regulated geologically hazardous areas include erosion, landslide, earthquake, or other geological hazards. Based on the definition in the Renton Municipal Code, the site does not contain geologically hazardous areas. 5.0 Discussion and Recommendations 5.1 GEOTECHNICAL CONSIDERATIONS Based on our study, the site is suitable for the proposed construction from a geotechnical standpoint. Foundations for the proposed residences can be supported on conventional spread footings bearing on competent native soil or structural fill. Slab-on-grade floors can be similarly supported. Detailed recommendations regarding the above issues and other geotechnical design considerations are provided in the following sections. These recommendations should be incorporated into the final design drawings and construction specifications. 5.2 EARTHWORK The earthwork is expected to include excavating and backfilling the building foundations and preparing slab subgrades. 5.2.1 EROSION AND SEDIMENT CONTROL Potential sources or causes of erosion and sedimentation depend on construction methods, slope length and gradient, amount of soil exposed and/or disturbed, soil type, construction sequencing and weather. The impacts on erosion-prone areas can be reduced by implementing an erosion and sedimentation control plan. The plan should be designed in accordance with applicable city and/or county standards. RGI recommends the following erosion control Best Management Practices (BMPs): Scheduling site preparation and grading for the drier summer and early fall months and undertaking activities that expose soil during periods of little or no rainfall Retaining existing vegetation whenever feasible Establishing a quarry spall construction entrance Installing siltation control fencing or anchored straw or coir wattles on the downhill side of work areas Covering soil stockpiles with anchored plastic sheeting Revegetating or mulching exposed soils with a minimum 3-inch thickness of straw if surfaces will be left undisturbed for more than one day during wet weather or one week in dry weather Directing runoff away from exposed soils and slopes Geotechnical Engineering Report 5 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 Minimizing the length and steepness of slopes with exposed soils and cover excavation surfaces with anchored plastic sheeting Decreasing runoff velocities with check dams, straw bales or coir wattles Confining sediment to the project site Inspecting and maintaining erosion and sediment control measures frequently (The contractor should be aware that inspection and maintenance of erosion control BMPs is critical toward their satisfactory performance. Repair and/or replacement of dysfunctional erosion control elements should be anticipated.) Permanent erosion protection should be provided by reestablishing vegetation using hydroseeding and/or landscape planting. Until the permanent erosion protection is established, site monitoring should be performed by qualified personnel to evaluate the effectiveness of the erosion control measures. Provisions for modifications to the erosion control system based on monitoring observations should be included in the erosion and sedimentation control plan. 5.2.2 STRIPPING AND SUBGRADE PREPARATION Stripping efforts should include removal of pavements, vegetation, organic materials, and deleterious debris from areas slated for building, pavement, and utility construction. Minimal ground cover/mulch was observed in the test pit and hand auger locations, however, deeper areas of stripping may be required in forested or heavily vegetated areas of the site. Subgrade soils that become disturbed due to elevated moisture conditions should be overexcavated to reveal firm, non-yielding, non-organic soils and backfilled with compacted structural fill. In order to maximize utilization of site soils as structural fill, RGI recommends that the earthwork portion of this project be completed during extended periods of warm and dry weather if possible. If earthwork is completed during the wet season (typically November through May) it will be necessary to take extra precautionary measures to protect subgrade soils. Wet season earthwork will require additional mitigative measures beyond that which would be expected during the drier summer and fall months. 5.2.3 EXCAVATIONS All temporary cut slopes associated with the site and utility excavations should be adequately inclined to prevent sloughing and collapse. The site soils consist of medium dense silty sand with gravel over very dense glacial till. Accordingly, for excavations more than 4 feet but less than 20 feet in depth, the temporary side slopes should be laid back with a minimum slope inclination of 1H:1V (Horizontal:Vertical). For open cuts at the site, RGI recommends: Geotechnical Engineering Report 6 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 No traffic, construction equipment, stockpiles or building supplies are allowed at the top of cut slopes within a distance of at least five feet from the top of the cut Exposed soil along the slope is protected from surface erosion using waterproof tarps and/or plastic sheeting Construction activities are scheduled so that the length of time the temporary cut is left open is minimized Surface water is diverted away from the excavation The general condition of slopes should be observed periodically by a geotechnical engineer to confirm adequate stability and erosion control measures In all cases, however, appropriate inclinations will depend on the actual soil and groundwater conditions encountered during earthwork. Ultimately, the site contractor must be responsible for maintaining safe excavation slopes that comply with applicable OSHA or WISHA guidelines. 5.2.4 STRUCTURAL FILL RGI recommends fill below the foundation and floor slab, behind retaining walls, and below pavement and hardscape surfaces be placed in accordance with the following recommendations for structural fill. The suitability of excavated site soils and import soils for compacted structural fill use will depend on the gradation and moisture content of the soil when it is placed. As the amount of fines (that portion passing the U.S. No. 200 sieve) increases, soil becomes increasingly sensitive to small changes in moisture content and adequate compaction becomes more difficult or impossible to achieve. Soils containing more than about 5 percent fines cannot be consistently compacted to a dense, non-yielding condition when the moisture content is more than 2 percent above or below optimum. Optimum moisture content is that moisture that results in the greatest compacted dry density with a specified compactive effort. Non-organic site soils are only considered suitable for structural fill provided that their moisture content is within about two percent of the optimum moisture level as determined by American Society of Testing and Materials D1557-09 Standard Test Methods for Laboratory Compaction Characteristics of Soil Using Modified Effort (ASTM D1557). Excavated site soils may not be suitable for re-use as structural fill depending on the moisture content and weather conditions at the time of construction. If soils are stockpiled for future reuse and wet weather is anticipated, the stockpile should be protected with plastic sheeting that is securely anchored. Even during dry weather, moisture conditioning (such as, windrowing and drying) of site soils to be reused as structural fill may be required. Geotechnical Engineering Report 7 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 The site soils are moisture sensitive and may require moisture conditioning prior to use as structural fill. If on-site soils are or become unusable, it may become necessary to import clean, granular soils to complete site work that meet the grading requirements listed in Table 2 to be used as structural fill. Table 2 Structural Fill Gradation U.S. Sieve Size Percent Passing 4 inches 100 No. 4 sieve 22 to 100 No. 200 sieve 0 to 5* *Based on minus 3/4 inch fraction. Prior to use, an RGI representative should observe and test all materials imported to the site for use as structural fill. Structural fill materials should be placed in uniform loose layers not exceeding 12 inches and compacted as specified in Table 3. The soil’s maximum density and optimum moisture should be determined by ASTM D1557. Table 3 Structural Fill Compaction ASTM D1557 Location Material Type Minimum Compaction Percentage Moisture Content Range Foundations On-site granular or approved imported fill soils: 95 +2 -2 Retaining Wall Backfill On-site granular or approved imported fill soils: 92 +2 -2 Slab-on-grade On-site granular or approved imported fill soils: 95 +2 -2 General Fill (non- structural areas) On-site soils or approved imported fill soils: 90 +3 -2 Placement and compaction of structural fill should be observed by RGI. A representative number of in-place density tests should be performed as the fill is being placed to confirm that the recommended level of compaction is achieved. 5.2.5 WET WEATHER CONSTRUCTION CONSIDERATIONS RGI recommends that preparation for site grading and construction include procedures intended to drain ponded water, control surface water runoff, and to collect shallow Geotechnical Engineering Report 8 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 subsurface seepage zones in excavations where encountered. It will not be possible to successfully compact the subgrade or utilize on-site soils as structural fill if accumulated water is not drained prior to grading or if drainage is not controlled during construction. Attempting to grade the site without adequate drainage control measures will reduce the amount of on-site soil effectively available for use, increase the amount of select import fill materials required, and ultimately increase the cost of the earthwork phases of the project. Free water should not be allowed to pond on the subgrade soils. RGI anticipates that the use of berms and shallow drainage ditches, with sumps and pumps in utility trenches, will be required for surface water control during wet weather and/or wet site conditions. 5.3 FOUNDATIONS Following site preparation and grading, the proposed building foundation can be supported on conventional spread footings bearing on competent native soil or structural fill. Loose, organic, or other unsuitable soils may be encountered in the proposed building footprint. If unsuitable soils are encountered, they should be overexcavated and backfilled with structural fill. If loose soils are encountered, the soils should be moisture conditioned and compacted to a firm and unyielding condition. The foundation design value assumes the foundation is supported on at least two feet of medium dense native soil or structural fill. Table 4 Foundation Design Design Parameter Value Allowable Bearing Capacity 2,000 psf1 Friction Coefficient 0.30 Passive pressure (equivalent fluid pressure) 250 pcf2 Minimum foundation dimensions Columns: 24 inches Walls: 16 inches 1. psf = pounds per square foot 2. pcf = pounds per cubic foot The allowable foundation bearing pressures apply to dead loads plus design live load conditions. For short-term loads, such as wind and seismic, a 1/3 increase in this allowable capacity may be used. At perimeter locations, RGI recommends not including the upper 12 inches of soil in the computation of passive pressures because they can be affected by weather or disturbed by future grading activity. The passive pressure value assumes the foundation will be constructed neat against competent soil or backfilled with structural fill as described in Section 5.2.4. The recommended base friction and passive resistance value includes a safety factor of about 1.5. Geotechnical Engineering Report 9 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 Perimeter foundations exposed to weather should be at a minimum depth of 18 inches below final exterior grades. Interior foundations can be constructed at any convenient depth below the floor slab. Finished grade is defined as the lowest adjacent grade within 5 feet of the foundation for perimeter (or exterior) footings and finished floor level for interior footings. With spread footing foundations designed in accordance with the recommendations in this section, maximum total and differential post-construction settlements of 1 inch and 1/2 inch, respectively, should be expected. 5.4 RETAINING WALLS If retaining walls are needed in the building area, RGI recommends cast-in-place concrete walls be used. The magnitude of earth pressure development on retaining walls will partly depend on the quality of the wall backfill. RGI recommends placing and compacting wall backfill as structural fill. Wall drainage will be needed behind the wall face. A typical retaining wall drainage detail is shown in Figure 3. With wall backfill placed and compacted as recommended, and drainage properly installed, RGI recommends using the values in the following table for design. Table 5 Retaining Wall Design Design Parameter Value Allowable Bearing Capacity 2,000 psf Active Earth Pressure (unrestrained walls) 35 pcf At-rest Earth Pressure (restrained walls) 50 pcf For seismic design, an additional uniform load of 7 times the wall height (H) for unrestrained walls and 14H in psf for restrained walls should be applied to the wall surface. Friction at the base of foundations and passive earth pressure will provide resistance to these lateral loads. Values for these parameters are provided in Section 5.3. 5.5 SLAB-ON-GRADE CONSTRUCTION Once site preparation has been completed as described in Section 5.2, suitable support for slab-on-grade construction should be provided. RGI recommends that the concrete slab be placed on top of medium dense native soil or structural fill. Immediately below the floor slab, RGI recommends placing a four-inch thick capillary break layer of clean, free-draining sand or gravel that has less than five percent passing the U.S. No. 200 sieve. This material will reduce the potential for upward capillary movement of water through the underlying soil and subsequent wetting of the floor slab. Where moisture by vapor transmission is Geotechnical Engineering Report 10 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 undesirable, an 8- to 10-millimeter thick plastic membrane should be placed on a 4-inch thick layer of clean gravel. For the anticipated floor slab loading, we estimate post-construction floor settlements of 1/4- to 1/2-inch. 5.6 DRAINAGE 5.6.1 SURFACE Final exterior grades should promote free and positive drainage away from the building area. Water must not be allowed to pond or collect adjacent to foundations or within the immediate building area. For non-pavement locations, RGI recommends providing a minimum drainage gradient of 3 percent for a minimum distance of 10 feet from the building perimeter. In paved locations, a minimum gradient of 1 percent should be provided unless provisions are included for collection and disposal of surface water adjacent to the structure. 5.6.2 SUBSURFACE RGI recommends installing perimeter foundation drains. A typical footing drain detail is shown on Figure 4. The foundation drains and roof downspouts should be tightlined separately to an approved discharge facility. Subsurface drains must be laid with a gradient sufficient to promote positive flow to a controlled point of approved discharge. 5.6.3 INFILTRATION The site is underlain by very dense glacial till, commonly referred to as “hardpan.” This material does not allow for infiltration. 5.7 UTILITIES Utility pipes should be bedded and backfilled in accordance with American Public Works Association (APWA) specifications. For site utilities located within the right-of-ways, bedding and backfill should be completed in accordance with City of Renton specifications. At a minimum, trench backfill should be placed and compacted as structural fill, as described in Section 5.2.4. Where utilities occur below unimproved areas, the degree of compaction can be reduced to a minimum of 90 percent of the soil’s maximum density as determined by the referenced ASTM D1557. As noted, soils excavated on site will not be suitable for use as backfill material. Imported structural fill meeting the gradation provided in Table 2 should be used for trench backfill. Geotechnical Engineering Report 11 April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 6.0 Additional Services RGI is available to provide further geotechnical consultation throughout the design phase of the project. RGI should review the final design and specifications in order to verify that earthwork and foundation recommendations have been properly interpreted and incorporated into project design and construction. RGI is also available to provide geotechnical engineering and construction monitoring services during construction. The integrity of the earthwork and construction depends on proper site preparation and procedures. In addition, engineering decisions may arise in the field in the event that variations in subsurface conditions become apparent. Construction monitoring services are not part of this scope of work. If these services are desired, please let us know and we will prepare a cost proposal. 7.0 Limitations This GER is the property of RGI, Kushal Varma, and its designated agents. Within the limits of the scope and budget, this GER was prepared in accordance with generally accepted geotechnical engineering practices in the area at the time this GER was issued. This GER is intended for specific application to the proposed Varma 3-Lot Plat in Renton, Washington, and for the exclusive use of Kushal Varma and its authorized representatives. No other warranty, expressed or implied, is made. Site safety, excavation support, and dewatering requirements are the responsibility of others. The scope of services for this project does not include either specifically or by implication any environmental or biological (for example, mold, fungi, bacteria) assessment of the site or identification or prevention of pollutants, hazardous materials or conditions. If the owner is concerned about the potential for such contamination or pollution, we can provide a proposal for these services. The analyses and recommendations presented in this GER are based upon data obtained from the explorations performed on site. Variations in soil conditions can occur, the nature and extent of which may not become evident until construction. If variations appear evident, RGI should be requested to reevaluate the recommendations in this GER prior to proceeding with construction. It is the client’s responsibility to see that all parties to the project, including the designers, contractors, subcontractors, are made aware of this GER in its entirety. The use of information contained in this GER for bidding purposes should be done at the contractor’s option and risk. USGS, 2020, Renton, Washington USGS, 2020, Maple Valley, Washington 7.5-Minute Quadrangle Approximate Scale: 1"=1000' 0 500 1000 2000 N Site Vicinity Map Figure 1 04/2025 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Varma 3-Lot Short Plat RGI Project Number: 2020-317-1 Date Drawn: Address: 13011 156th Avenue Southeast, Renton, Washington 98059 SITE TP-4 TP-3 04/2025 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Varma 3-Lot Short Plat RGI Project Number: 2020-317-1 Date Drawn: Address: 13011 156th Avenue Southeast, Renton, Washington 98059 Figure 2 Approximate Scale: 1"=50' 0 25 50 100 N = Test pit locations by RGI, 08/24/2020 = Site boundary Geotechnical Exploration Plan Incliniations) 12" Over the Pipe 3" Below the Pipe Perforated Pipe 4" Diameter PVC Compacted Structural Backfill (Native or Import) 12" min. Filter Fabric Material 12" Minimum Wide Free-Draining Gravel Slope to Drain (See Report for Appropriate Excavated Slope 04/2025 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Varma 3-Lot Short Plat RGI Project Number: 2020-317-1 Date Drawn: Address: 13011 156th Avenue Southeast, Renton, Washington 98059 Retaining Wall Drainage Detail Figure 3 Not to Scale Building Slab Structural Backfill Compacted 04/2025 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Varma 3-Lot Short Plat RGI Project Number: 2020-317-1 Date Drawn: Address: 13011 156th Avenue Southeast, Renton, Washington 98059 Typical Foundation Drainage Detail Figure 4 Not to Scale Gravel or Crushed Stone with less than 10% passing No. 4 (4.75mm) Sieve 12" Minimum 4" Perforated Pipe (See Report Text) Approved Filter Membrane Material Geotechnical Engineering Report April 8, 2025 Varma 3-Lot Short Plat, Renton, Washington RGI Project No. 2020-317-1 APPENDIX A FIELD EXPLORATION AND LABORATORY TESTING On August 24, 2020, RGI performed field explorations using a trackhoe. We explored subsurface soil conditions at the site by observing the excavation of two test pits. The test pit locations are shown on Figure 2. The test pit locations were approximately determined by measurements from existing property lines and paved roads. A geologist from our office conducted the field exploration and classified the soil conditions encountered, maintained a log of each test exploration, obtained representative soil samples, and observed pertinent site features. All soil samples were visually classified in accordance with the Unified Soil Classification System (USCS). Representative soil samples obtained from the explorations were placed in closed containers and taken to our laboratory for further examination and testing. As a part of the laboratory testing program, the soil samples were classified in our in house laboratory based on visual observation, texture, plasticity, and the limited laboratory testing described below. Moisture Content Determinations Moisture content determinations were performed in accordance with ASTM D2216-10 Standard Test Methods for Laboratory Determination of Water (Moisture) Content of Soil and Rock by Mass (ASTM D2216) on representative samples obtained from the exploration in order to aid in identification and correlation of soil types. The moisture content of typical sample was measured and is reported on the test pit logs. Grain Size Analysis A grain size analysis indicates the range in diameter of soil particles included in a particular sample. Grain size analyses was determined using D6913-04(2009) Standard Test Methods for Particle-Size Distribution (Gradation) of Soils Using Sieve Analysis (ASTM D6913) on two of the samples. Project Name: Varma 3-Lot Short Plat Project Number: 2020-317-1 Client: Kushal Varma Test Pit No.: TP-3 Date(s) Excavated:08/24/20 Excavation Method: Excavator Type: Groundwater Level:Not encountered Test Pit Backfill:Native Soil Logged By LC Bucket Size:n/a Excavating Contractor:Client Provided Sampling Method(s)Grab Location 13014 156th Avenue Southeast, Renton, Washington 98059 Surface Conditions:Mulch Total Depth of Excavation:4.5 feet bgs Approximate Surface Elevation n/a Compaction Method n/a US C S S y m b o l SM SM REMARKS AND OTHER TESTSGr a p h i c L o g MATERIAL DESCRIPTION Brown, silty SAND with some gravel, medium dense, moist Gray, silty SAND with gravel (till), very dense, moist Test pit excavated to 4.5 feet bgs No groundwater encountered De p t h ( f e e t ) 0 5 10 Sa m p l e N u m b e r Sa m p l e T y p e El e v a t i o n ( f e e t ) Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Varma 3-Lot Short Plat Project Number: 2020-317-1 Client: Kushal Varma Test Pit No.: TP-4 Date(s) Excavated:08/24/20 Excavation Method: Excavator Type: Groundwater Level:Not encountered Test Pit Backfill:Native Soil Logged By LC Bucket Size:n/a Excavating Contractor:Client Provided Sampling Method(s)Grab Location 13014 156th Avenue Southeast, Renton, Washington 98059 Surface Conditions:Mulch Total Depth of Excavation:4.5 feet bgs Approximate Surface Elevation n/a Compaction Method n/a US C S S y m b o l SM SM REMARKS AND OTHER TESTSGr a p h i c L o g MATERIAL DESCRIPTION Brown, silty SAND with gravel, medium dense, moist Gray, silty SAND with gravel (till), very dense, moist Test pit excavated to 4.5 feet bgs No groundwater encountered De p t h ( f e e t ) 0 5 10 Sa m p l e N u m b e r Sa m p l e T y p e El e v a t i o n ( f e e t ) Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name: Varma 3-Lot Short Plat Project Number: 2020-317-1 Client: Kushal Varma Key to Logs US C S S y m b o l REMARKS AND OTHER TESTSGr a p h i c L o g MATERIAL DESCRIPTIONDe p t h ( f e e t ) Sa m p l e N u m b e r Sa m p l e T y p e El e v a t i o n ( f e e t ) 1 2 3 4 5 6 7 8 COLUMN DESCRIPTIONS 1 Elevation (feet): Elevation (MSL, feet). 2 Depth (feet): Depth in feet below the ground surface. 3 Sample Type: Type of soil sample collected at the depth interval shown. 4 Sample Number: Sample identification number. 5 USCS Symbol: USCS symbol of the subsurface material. 6 Graphic Log: Graphic depiction of the subsurface material encountered. 7 MATERIAL DESCRIPTION: Description of material encountered. May include consistency, moisture, color, and other descriptive text. 8 REMARKS AND OTHER TESTS: Comments and observations regarding drilling or sampling made by driller or field personnel. FIELD AND LABORATORY TEST ABBREVIATIONS CHEM: Chemical tests to assess corrosivity COMP: Compaction test CONS: One-dimensional consolidation test LL: Liquid Limit, percent PI: Plasticity Index, percent SA: Sieve analysis (percent passing No. 200 Sieve) UC: Unconfined compressive strength test, Qu, in ksf WA: Wash sieve (percent passing No. 200 Sieve) MATERIAL GRAPHIC SYMBOLS Silty SAND (SM) TYPICAL SAMPLER GRAPHIC SYMBOLS Auger sampler Bulk Sample 3-inch-OD California w/ brass rings CME Sampler Grab Sample 2.5-inch-OD Modified California w/ brass liners Pitcher Sample 2-inch-OD unlined split spoon (SPT) Shelby Tube (Thin-walled, fixed head) OTHER GRAPHIC SYMBOLS Water level (at time of drilling, ATD) Water level (after waiting) Minor change in material properties within a stratum Inferred/gradational contact between strata ?Queried contact between strata GENERAL NOTES 1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual lithologic changes may be gradual. Field descriptions may have been modified to reflect results of lab tests. 2: Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative of subsurface conditions at other locations or times. Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Varma Renton 3 Lot Short Plat Technical Information Report Appendix C WWHM Output WWHM2012 PROJECT REPORT Varma 3-Lot 4/10/2025 12:49:18 PM Page 2 General Model Information WWHM2012 Project Name:Varma 3-Lot Site Name:Varma SFR Site Address: City: Report Date:4/10/2025 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:Hourly Precip Scale:1.167 Version Date:2023/01/27 Version:4.2.19 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Low Flow Threshold for POC2:50 Percent of the 2 Year High Flow Threshold for POC2:50 Year Varma 3-Lot 4/10/2025 12:49:18 PM Page 3 Landuse Basin Data Predeveloped Land Use West Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.216 Pervious Total 0.216 Impervious Land Use acre Impervious Total 0 Basin Total 0.216 Varma 3-Lot 4/10/2025 12:49:18 PM Page 4 East Basin Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.424 Pervious Total 0.424 Impervious Land Use acre Impervious Total 0 Basin Total 0.424 Varma 3-Lot 4/10/2025 12:49:18 PM Page 5 Mitigated Land Use West Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.01 C, Pasture, Flat 0.091 Pervious Total 0.101 Impervious Land Use acre ROADS FLAT 0.009 ROOF TOPS FLAT 0.083 DRIVEWAYS FLAT 0.023 Impervious Total 0.115 Basin Total 0.216 Varma 3-Lot 4/10/2025 12:49:18 PM Page 6 East Basin Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.015 C, Pasture, Flat 0.2549 Pervious Total 0.2699 Impervious Land Use acre ROADS FLAT 0.0525 ROOF TOPS FLAT 0.0826 DRIVEWAYS FLAT 0.023 Impervious Total 0.1581 Basin Total 0.428 Varma 3-Lot 4/10/2025 12:49:18 PM Page 7 Routing Elements Predeveloped Routing Varma 3-Lot 4/10/2025 12:49:18 PM Page 8 Mitigated Routing Varma 3-Lot 4/10/2025 12:49:18 PM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.216 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.101 Total Impervious Area:0.115 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.007687 5 year 0.012266 10 year 0.015244 25 year 0.018847 50 year 0.021393 100 year 0.023816 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.038519 5 year 0.049331 10 year 0.056909 25 year 0.066983 50 year 0.074862 100 year 0.083072 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.008 0.039 1950 0.016 0.062 1951 0.017 0.040 1952 0.006 0.031 1953 0.005 0.029 1954 0.006 0.036 1955 0.011 0.038 1956 0.009 0.036 1957 0.008 0.043 1958 0.008 0.037 Varma 3-Lot 4/10/2025 12:49:31 PM Page 10 1959 0.006 0.029 1960 0.012 0.037 1961 0.006 0.032 1962 0.004 0.031 1963 0.006 0.032 1964 0.006 0.037 1965 0.006 0.032 1966 0.005 0.033 1967 0.011 0.048 1968 0.006 0.053 1969 0.007 0.031 1970 0.006 0.033 1971 0.006 0.032 1972 0.013 0.048 1973 0.006 0.030 1974 0.006 0.034 1975 0.010 0.046 1976 0.006 0.031 1977 0.001 0.035 1978 0.006 0.047 1979 0.003 0.046 1980 0.009 0.042 1981 0.005 0.045 1982 0.012 0.062 1983 0.008 0.042 1984 0.005 0.035 1985 0.003 0.030 1986 0.014 0.043 1987 0.012 0.052 1988 0.005 0.025 1989 0.003 0.033 1990 0.019 0.068 1991 0.016 0.062 1992 0.006 0.034 1993 0.006 0.022 1994 0.002 0.026 1995 0.008 0.034 1996 0.016 0.046 1997 0.016 0.042 1998 0.004 0.041 1999 0.010 0.077 2000 0.006 0.042 2001 0.001 0.033 2002 0.008 0.043 2003 0.006 0.039 2004 0.015 0.076 2005 0.008 0.034 2006 0.010 0.031 2007 0.026 0.076 2008 0.021 0.062 2009 0.012 0.041 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0256 0.0771 2 0.0215 0.0761 3 0.0190 0.0758 Varma 3-Lot 4/10/2025 12:49:31 PM Page 11 4 0.0170 0.0677 5 0.0162 0.0624 6 0.0159 0.0619 7 0.0157 0.0618 8 0.0155 0.0617 9 0.0153 0.0526 10 0.0135 0.0525 11 0.0132 0.0480 12 0.0124 0.0479 13 0.0124 0.0467 14 0.0117 0.0459 15 0.0115 0.0457 16 0.0107 0.0456 17 0.0106 0.0447 18 0.0100 0.0431 19 0.0100 0.0431 20 0.0097 0.0426 21 0.0093 0.0419 22 0.0092 0.0419 23 0.0084 0.0418 24 0.0082 0.0417 25 0.0081 0.0413 26 0.0080 0.0406 27 0.0079 0.0404 28 0.0078 0.0394 29 0.0078 0.0389 30 0.0067 0.0377 31 0.0065 0.0375 32 0.0064 0.0373 33 0.0064 0.0369 34 0.0064 0.0361 35 0.0063 0.0360 36 0.0063 0.0350 37 0.0063 0.0346 38 0.0063 0.0341 39 0.0062 0.0339 40 0.0061 0.0338 41 0.0059 0.0336 42 0.0059 0.0333 43 0.0058 0.0332 44 0.0058 0.0331 45 0.0057 0.0330 46 0.0057 0.0325 47 0.0056 0.0322 48 0.0055 0.0320 49 0.0053 0.0318 50 0.0051 0.0313 51 0.0050 0.0309 52 0.0049 0.0306 53 0.0046 0.0306 54 0.0041 0.0305 55 0.0039 0.0301 56 0.0034 0.0299 57 0.0030 0.0295 58 0.0029 0.0289 59 0.0021 0.0257 60 0.0014 0.0247 61 0.0012 0.0221 Varma 3-Lot 4/10/2025 12:49:31 PM Page 12 Varma 3-Lot 4/10/2025 12:49:31 PM Page 13 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0038 4767 24982 524 Fail 0.0040 4283 23918 558 Fail 0.0042 3916 22854 583 Fail 0.0044 3584 21875 610 Fail 0.0046 3270 20924 639 Fail 0.0047 2968 20015 674 Fail 0.0049 2711 19191 707 Fail 0.0051 2505 18378 733 Fail 0.0053 2309 17672 765 Fail 0.0054 2117 16983 802 Fail 0.0056 1937 16325 842 Fail 0.0058 1791 15699 876 Fail 0.0060 1646 15090 916 Fail 0.0061 1533 14534 948 Fail 0.0063 1415 13994 988 Fail 0.0065 1316 13475 1023 Fail 0.0067 1239 12978 1047 Fail 0.0069 1141 12502 1095 Fail 0.0070 1071 12047 1124 Fail 0.0072 999 11603 1161 Fail 0.0074 931 11186 1201 Fail 0.0076 861 10737 1247 Fail 0.0077 804 10358 1288 Fail 0.0079 750 9956 1327 Fail 0.0081 703 9598 1365 Fail 0.0083 654 9251 1414 Fail 0.0085 608 8946 1471 Fail 0.0086 572 8588 1501 Fail 0.0088 533 8310 1559 Fail 0.0090 504 8042 1595 Fail 0.0092 476 7775 1633 Fail 0.0093 445 7475 1679 Fail 0.0095 417 7197 1725 Fail 0.0097 394 6930 1758 Fail 0.0099 356 6695 1880 Fail 0.0100 331 6470 1954 Fail 0.0102 311 6229 2002 Fail 0.0104 294 6000 2040 Fail 0.0106 280 5812 2075 Fail 0.0108 264 5625 2130 Fail 0.0109 253 5433 2147 Fail 0.0111 239 5275 2207 Fail 0.0113 227 5107 2249 Fail 0.0115 217 4929 2271 Fail 0.0116 203 4759 2344 Fail 0.0118 189 4600 2433 Fail 0.0120 176 4451 2528 Fail 0.0122 165 4304 2608 Fail 0.0124 154 4158 2700 Fail 0.0125 144 4023 2793 Fail 0.0127 132 3898 2953 Fail 0.0129 120 3780 3150 Fail 0.0131 110 3658 3325 Fail 0.0132 102 3580 3509 Fail Varma 3-Lot 4/10/2025 12:49:31 PM Page 14 0.0134 97 3478 3585 Fail 0.0136 88 3376 3836 Fail 0.0138 83 3258 3925 Fail 0.0139 76 3164 4163 Fail 0.0141 70 3064 4377 Fail 0.0143 60 2953 4921 Fail 0.0145 57 2870 5035 Fail 0.0147 48 2787 5806 Fail 0.0148 45 2699 5997 Fail 0.0150 41 2608 6360 Fail 0.0152 39 2535 6500 Fail 0.0154 36 2462 6838 Fail 0.0155 31 2381 7680 Fail 0.0157 27 2307 8544 Fail 0.0159 26 2245 8634 Fail 0.0161 23 2176 9460 Fail 0.0163 21 2114 10066 Fail 0.0164 19 2054 10810 Fail 0.0166 16 1996 12475 Fail 0.0168 15 1942 12946 Fail 0.0170 14 1880 13428 Fail 0.0171 11 1817 16518 Fail 0.0173 10 1765 17650 Fail 0.0175 10 1721 17210 Fail 0.0177 8 1672 20900 Fail 0.0178 8 1630 20375 Fail 0.0180 7 1580 22571 Fail 0.0182 7 1530 21857 Fail 0.0184 6 1490 24833 Fail 0.0186 6 1452 24200 Fail 0.0187 4 1413 35325 Fail 0.0189 4 1376 34400 Fail 0.0191 3 1331 44366 Fail 0.0193 2 1295 64750 Fail 0.0194 2 1251 62550 Fail 0.0196 2 1214 60700 Fail 0.0198 2 1173 58650 Fail 0.0200 2 1139 56950 Fail 0.0202 2 1108 55400 Fail 0.0203 2 1068 53400 Fail 0.0205 2 1042 52100 Fail 0.0207 2 1016 50800 Fail 0.0209 2 990 49500 Fail 0.0210 2 957 47850 Fail 0.0212 2 931 46550 Fail 0.0214 2 910 45500 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Varma 3-Lot 4/10/2025 12:49:31 PM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Varma 3-Lot 4/10/2025 12:49:31 PM Page 16 LID Report Varma 3-Lot 4/10/2025 12:49:56 PM Page 17 POC 2 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.424 Total Impervious Area:0 Mitigated Landuse Totals for POC #2 Total Pervious Area:0.2699 Total Impervious Area:0.1581 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.01509 5 year 0.024079 10 year 0.029922 25 year 0.036996 50 year 0.041994 100 year 0.046749 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.057365 5 year 0.074869 10 year 0.087318 25 year 0.104062 50 year 0.117295 100 year 0.131197 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.016 0.060 1950 0.031 0.099 1951 0.033 0.064 1952 0.011 0.044 1953 0.009 0.043 1954 0.013 0.054 1955 0.021 0.057 1956 0.018 0.056 1957 0.016 0.066 1958 0.015 0.055 1959 0.012 0.043 Varma 3-Lot 4/10/2025 12:50:09 PM Page 18 1960 0.024 0.057 1961 0.012 0.048 1962 0.008 0.045 1963 0.012 0.048 1964 0.013 0.055 1965 0.011 0.048 1966 0.010 0.050 1967 0.021 0.069 1968 0.013 0.074 1969 0.013 0.047 1970 0.011 0.050 1971 0.011 0.049 1972 0.026 0.075 1973 0.012 0.045 1974 0.012 0.050 1975 0.020 0.071 1976 0.012 0.047 1977 0.002 0.048 1978 0.011 0.067 1979 0.007 0.063 1980 0.018 0.064 1981 0.010 0.066 1982 0.023 0.094 1983 0.016 0.058 1984 0.010 0.052 1985 0.006 0.042 1986 0.027 0.069 1987 0.024 0.072 1988 0.010 0.034 1989 0.006 0.046 1990 0.037 0.108 1991 0.031 0.098 1992 0.011 0.050 1993 0.012 0.032 1994 0.004 0.035 1995 0.017 0.049 1996 0.032 0.074 1997 0.030 0.065 1998 0.008 0.059 1999 0.020 0.109 2000 0.012 0.062 2001 0.003 0.046 2002 0.015 0.065 2003 0.012 0.059 2004 0.030 0.117 2005 0.016 0.051 2006 0.019 0.049 2007 0.050 0.128 2008 0.042 0.098 2009 0.023 0.064 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0503 0.1278 2 0.0421 0.1174 3 0.0373 0.1093 4 0.0334 0.1078 Varma 3-Lot 4/10/2025 12:50:09 PM Page 19 5 0.0319 0.0989 6 0.0312 0.0982 7 0.0309 0.0979 8 0.0305 0.0940 9 0.0300 0.0754 10 0.0266 0.0742 11 0.0259 0.0736 12 0.0244 0.0723 13 0.0244 0.0709 14 0.0230 0.0691 15 0.0226 0.0687 16 0.0209 0.0671 17 0.0208 0.0660 18 0.0197 0.0657 19 0.0196 0.0651 20 0.0190 0.0651 21 0.0183 0.0642 22 0.0180 0.0636 23 0.0165 0.0636 24 0.0161 0.0632 25 0.0158 0.0623 26 0.0158 0.0601 27 0.0155 0.0591 28 0.0154 0.0585 29 0.0153 0.0578 30 0.0131 0.0571 31 0.0127 0.0566 32 0.0126 0.0559 33 0.0125 0.0551 34 0.0125 0.0551 35 0.0124 0.0537 36 0.0124 0.0516 37 0.0124 0.0510 38 0.0123 0.0502 39 0.0122 0.0498 40 0.0119 0.0497 41 0.0116 0.0495 42 0.0116 0.0494 43 0.0115 0.0490 44 0.0114 0.0486 45 0.0112 0.0483 46 0.0112 0.0483 47 0.0111 0.0480 48 0.0109 0.0475 49 0.0105 0.0470 50 0.0100 0.0466 51 0.0099 0.0457 52 0.0096 0.0457 53 0.0090 0.0450 54 0.0081 0.0445 55 0.0076 0.0436 56 0.0066 0.0431 57 0.0058 0.0428 58 0.0058 0.0421 59 0.0040 0.0354 60 0.0027 0.0340 61 0.0023 0.0324 Varma 3-Lot 4/10/2025 12:50:09 PM Page 20 Varma 3-Lot 4/10/2025 12:50:09 PM Page 21 Duration Flows The Duration Matching Failed Flow(cfs)Predev Mit Percentage Pass/Fail 0.0075 4766 20298 425 Fail 0.0079 4282 19127 446 Fail 0.0082 3917 18068 461 Fail 0.0086 3584 17116 477 Fail 0.0089 3269 16234 496 Fail 0.0093 2968 15373 517 Fail 0.0096 2711 14539 536 Fail 0.0100 2505 13780 550 Fail 0.0103 2312 13063 565 Fail 0.0107 2119 12416 585 Fail 0.0110 1938 11753 606 Fail 0.0114 1791 11176 624 Fail 0.0117 1645 10614 645 Fail 0.0121 1534 10112 659 Fail 0.0124 1421 9609 676 Fail 0.0128 1318 9165 695 Fail 0.0131 1239 8700 702 Fail 0.0135 1141 8299 727 Fail 0.0138 1072 7951 741 Fail 0.0142 999 7556 756 Fail 0.0145 931 7197 773 Fail 0.0149 861 6839 794 Fail 0.0152 804 6497 808 Fail 0.0155 751 6181 823 Fail 0.0159 703 5903 839 Fail 0.0162 654 5668 866 Fail 0.0166 608 5417 890 Fail 0.0169 572 5203 909 Fail 0.0173 534 4962 929 Fail 0.0176 504 4734 939 Fail 0.0180 476 4509 947 Fail 0.0183 445 4331 973 Fail 0.0187 417 4161 997 Fail 0.0190 397 3979 1002 Fail 0.0194 356 3809 1069 Fail 0.0197 330 3649 1105 Fail 0.0201 310 3499 1128 Fail 0.0204 295 3344 1133 Fail 0.0208 280 3209 1146 Fail 0.0211 264 3081 1167 Fail 0.0215 253 2938 1161 Fail 0.0218 239 2815 1177 Fail 0.0222 227 2694 1186 Fail 0.0225 217 2586 1191 Fail 0.0229 203 2501 1232 Fail 0.0232 189 2391 1265 Fail 0.0236 176 2297 1305 Fail 0.0239 165 2230 1351 Fail 0.0242 154 2162 1403 Fail 0.0246 143 2068 1446 Fail 0.0249 132 1983 1502 Fail 0.0253 120 1905 1587 Fail 0.0256 110 1832 1665 Fail 0.0260 102 1757 1722 Fail Varma 3-Lot 4/10/2025 12:50:09 PM Page 22 0.0263 97 1694 1746 Fail 0.0267 88 1640 1863 Fail 0.0270 83 1581 1904 Fail 0.0274 76 1512 1989 Fail 0.0277 70 1460 2085 Fail 0.0281 60 1407 2345 Fail 0.0284 57 1343 2356 Fail 0.0288 47 1303 2772 Fail 0.0291 45 1260 2800 Fail 0.0295 41 1219 2973 Fail 0.0298 39 1163 2982 Fail 0.0302 36 1120 3111 Fail 0.0305 31 1079 3480 Fail 0.0309 28 1041 3717 Fail 0.0312 26 1012 3892 Fail 0.0316 23 975 4239 Fail 0.0319 21 943 4490 Fail 0.0323 19 903 4752 Fail 0.0326 16 860 5375 Fail 0.0329 15 822 5480 Fail 0.0333 14 796 5685 Fail 0.0336 11 775 7045 Fail 0.0340 10 749 7490 Fail 0.0343 10 729 7290 Fail 0.0347 8 703 8787 Fail 0.0350 8 676 8450 Fail 0.0354 7 657 9385 Fail 0.0357 7 639 9128 Fail 0.0361 6 621 10350 Fail 0.0364 6 596 9933 Fail 0.0368 4 578 14450 Fail 0.0371 4 560 14000 Fail 0.0375 3 543 18100 Fail 0.0378 2 527 26350 Fail 0.0382 2 517 25850 Fail 0.0385 2 500 25000 Fail 0.0389 2 485 24250 Fail 0.0392 2 467 23350 Fail 0.0396 2 454 22700 Fail 0.0399 2 442 22100 Fail 0.0403 2 430 21500 Fail 0.0406 2 417 20850 Fail 0.0410 2 408 20400 Fail 0.0413 2 397 19850 Fail 0.0416 2 381 19050 Fail 0.0420 2 370 18500 Fail The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. Varma 3-Lot 4/10/2025 12:50:09 PM Page 23 Water Quality Water Quality BMP Flow and Volume for POC #2 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Varma 3-Lot 4/10/2025 12:50:09 PM Page 24 LID Report Varma 3-Lot 4/10/2025 12:50:09 PM Page 25 POC 3 POC #3 was not reported because POC must exist in both scenarios and both scenarios must have been run. Varma 3-Lot 4/10/2025 12:50:09 PM Page 26 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Varma 3-Lot 4/10/2025 12:50:09 PM Page 27 Appendix Predeveloped Schematic Varma 3-Lot 4/10/2025 12:50:11 PM Page 28 Mitigated Schematic Varma 3-Lot 4/10/2025 12:50:12 PM Page 29 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Varma 3-Lot.wdm MESSU 25 PreVarma 3-Lot.MES 27 PreVarma 3-Lot.L61 28 PreVarma 3-Lot.L62 30 POCVarma 3-Lot1.dat 31 POCVarma 3-Lot2.dat END FILES OPN SEQUENCE INGRP INDELT 00:60 PERLND 10 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 West Basin MAX 1 2 30 9 2 East Basin MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO Varma 3-Lot 4/10/2025 12:50:12 PM Page 30 <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 Varma 3-Lot 4/10/2025 12:50:12 PM Page 31 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** West Basin *** PERLND 10 0.216 COPY 501 12 PERLND 10 0.216 COPY 501 13 East Basin*** PERLND 10 0.424 COPY 502 12 PERLND 10 0.424 COPY 502 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 12.1 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 12.1 DISPLY 2 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS Varma 3-Lot 4/10/2025 12:50:12 PM Page 32 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.167 SUM PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 SUM IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 12.1 WDM 501 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 12.1 WDM 502 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN Varma 3-Lot 4/10/2025 12:50:12 PM Page 33 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Varma 3-Lot.wdm MESSU 25 MitVarma 3-Lot.MES 27 MitVarma 3-Lot.L61 28 MitVarma 3-Lot.L62 30 POCVarma 3-Lot1.dat 31 POCVarma 3-Lot2.dat END FILES OPN SEQUENCE INGRP INDELT 00:60 PERLND 16 PERLND 13 IMPLND 1 IMPLND 4 IMPLND 5 COPY 501 COPY 502 DISPLY 1 DISPLY 2 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 West Basin MAX 1 2 30 9 2 East Basin MAX 1 2 31 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 502 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 13 C, Pasture, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** Varma 3-Lot 4/10/2025 12:50:12 PM Page 34 # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 13 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 13 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 13 0 4.5 0.06 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 13 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 13 0.15 0.4 0.3 6 0.5 0.4 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 13 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 4 ROOF TOPS/FLAT 1 1 1 27 0 5 DRIVEWAYS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 4 0 0 1 0 0 0 5 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR Varma 3-Lot 4/10/2025 12:50:12 PM Page 35 # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 4 1 9 4 0 0 4 0 0 0 1 9 5 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 1 0 0 0 0 0 4 0 0 0 0 0 5 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 4 400 0.01 0.1 0.1 5 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 4 0 0 5 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 4 0 0 5 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** West Basin*** PERLND 16 0.01 COPY 501 12 PERLND 16 0.01 COPY 501 13 PERLND 13 0.091 COPY 501 12 PERLND 13 0.091 COPY 501 13 IMPLND 1 0.009 COPY 501 15 IMPLND 4 0.083 COPY 501 15 IMPLND 5 0.023 COPY 501 15 East Basin*** PERLND 16 0.015 COPY 502 12 PERLND 16 0.015 COPY 502 13 PERLND 13 0.2549 COPY 502 12 PERLND 13 0.2549 COPY 502 13 IMPLND 1 0.0525 COPY 502 15 IMPLND 4 0.0826 COPY 502 15 IMPLND 5 0.023 COPY 502 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 12.1 DISPLY 1 INPUT TIMSER 1 COPY 502 OUTPUT MEAN 1 1 12.1 DISPLY 2 INPUT TIMSER 1 Varma 3-Lot 4/10/2025 12:50:12 PM Page 36 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1.167 SUM PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1.167 SUM IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 12.1 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 12.1 WDM 801 FLOW ENGL REPL COPY 2 OUTPUT MEAN 1 1 12.1 WDM 702 FLOW ENGL REPL COPY 502 OUTPUT MEAN 1 1 12.1 WDM 802 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 Varma 3-Lot 4/10/2025 12:50:12 PM Page 37 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Varma 3-Lot 4/10/2025 12:50:12 PM Page 38 Predeveloped HSPF Message File Varma 3-Lot 4/10/2025 12:50:12 PM Page 39 Mitigated HSPF Message File Varma 3-Lot 4/10/2025 12:50:12 PM Page 40 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2025; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com Varma Renton 3 Lot Short Plat Technical Information Report Appendix D Operations and Maintenance Manual