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Home My WebLink About22073 TIR - 1011 N 35t StTECHNICAL INFORMATION REPORT June 16, 2023 PROJECT Aguilar Residence 1011 N 35th St Renton, WA 98056 OWNER Gary and Kaci Aguilar 1011 N 35th Street Renton, WA 98056 CONTRACTOR Straight Arrow Homes LLC C/O Brandon Shimizu 12015 NE 8th St, Ste 5 Bellevue, WA, 98005-3141 ENGINEER Andy Epstein Ethos Civil 748 Market Street Tacoma WA 9840 (253) 366-5483 andy@ethoscivil.com PREPARED BY Noah Burlingame Ethos Civil 748 Market Street Tacoma, WA 9840 (253) 366-5488 noah@ethoscivil.com AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 2 of 39 TABLE OF CONTENTS TECHNICAL INFORMATION REPORT ............................................................................................................. 1 PROJECT ................................................................................................................................................ 1 owner .................................................................................................................................................... 1 Contractor ............................................................................................................................................. 1 engineer ................................................................................................................................................ 1 prepared by ........................................................................................................................................... 1 PROJECT ENGINEERS CERTIFICATE ................................................................................................................ 4 DRAINAGE REPORT ....................................................................................................................................... 4 Section 1 – Project Overview .................................................................................................................... 4 Onsite Soils ............................................................................................................................................ 5 Figure 1.1 – TIR Worksheet ............................................................................................................... 6 Figure 1.2 – Site Location .................................................................................................................. 7 Figure 1.3 – Aerial Site Photo ............................................................................................................ 8 eXISTING AND dEVELOPED CONDTIONS ............................................................................................... 9 Figure 1.4 – Developed and Existing Basin Area Summary ............................................................... 9 Figure 1.5 – Existing Basin Map ...................................................................................................... 10 Figure 1.6 – Developed Basin Map ................................................................................................. 11 Section 2 – Conditions and Requirements Summary ............................................................................. 12 Drainage Review Type ..................................................................................................................... 12 Figure 2.1 – Renton Surface Water Design Manual Flow Chart for Determining Type of Drainge Review Required ............................................................................................................................. 14 Core Requirement #1: Discharge at the Natural Location .............................................................. 15 Core Requirement #2: Offsite Analysis ........................................................................................... 15 Core Requirement #3: Flow Control ............................................................................................... 15 Core Requirement #4: Conveyance System .................................................................................... 15 Core Requirement #5: CSWPP ........................................................................................................ 15 Core Requirement #6: Maintenance and Operations ..................................................................... 15 Core Requirement #7: Financial Guarantees and Liability .............................................................. 16 Core Requirement #8: Water Quality Facilities .............................................................................. 16 Core Requirement #9: Flow Control BMPs ..................................................................................... 16 Special Requirement #1: Other Adopted Areas-Specific Requirement .......................................... 17 Special Requirement #2: Flood Hazard Area Delineation ............................................................... 17 Special Requirement #3: Flood Protection Facility ......................................................................... 17 Special Requirement #4: Source Control ........................................................................................ 17 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 3 of 39 Special Requirement #5: Oil Control ............................................................................................... 17 Special Requirement #6: Aquifer Protection Area .......................................................................... 18 Section 3 – Offsite Analysis ..................................................................................................................... 18 Figure 3.1 – Downstream Map........................................................................................................ 19 Figure 3.2 – City of Renton Critical Areas Map ............................................................................... 21 Section 4 – Flow Control, LID and WQ Facility Analysis and Design ....................................................... 26 Part A: Existing Site Hydrology ............................................................................................................ 26 Part B: developed site hydrology ........................................................................................................ 26 Part C: Performance Standards ........................................................................................................... 26 Part D: FLOW CONTROL SYSTEM ........................................................................................................ 26 Figure 4.1 – Existing vs Developed Peak Flows (POC 1) .................................................................. 27 Part E: WATER QUALITY SYSTEM ........................................................................................................ 27 Section 5 – Conveyance System Analysis and Design ............................................................................. 28 Section 6 – Special Reports and Studies ................................................................................................. 29 Section 7 – Other Permits ....................................................................................................................... 29 Section 8 – Construction Stormwater Pollution Prevention Analysis and Design .................................. 29 Section 9 – Bond Quantities, Facility Summaries, and Declaration of Covenant ................................... 31 Section 10 – Operations and Maintenance Manual ............................................................................... 31 APPENDICES ................................................................................................................................................ 32 APPENDIX A – SURVEY ................................................................................................................................ 33 APPENDIX B – GEOTECHNICAL REPORT ...................................................................................................... 34 APPENDIX C – DECLARATION OF COVENANT ............................................................................................. 35 APPENDIX D – OPERATIONS AND MAINTENANCE MANUAL ...................................................................... 36 APPENDIX F – DOWNSTREAM INLET CALCULATIONS ................................................................................. 38 APPENDIX G – STORM MAIN CONVEYANCE CALCULATIONS ...................................................................... 39 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 4 of 39 PROJECT ENGINEERS CERTIFICATE I hereby state that this report for the residential project at 1011 N 35th Street, Renton, Washington has been prepared by me or under my supervision and meets the standard of care and expertise which is usual and customary in this community for professional engineers. DRAINAGE REPORT Section 1 – Project Overview The project site is in the City of Renton on the south side of N 35th Street, on tax parcel 334210-2545, which is zoned R-8 (single family residential). Current improvements on site include a single-family residence, a paved walkway, and a paved driveway. The property is vegetated with lawn-grass, shrubs, and trees. All onsite improvements will be removed as a part of the development process. The site is bound by single family residences to the east, south and west, and by N 35th St to the north. The site slopes from southeast to northwest at approximately 1 percent to 8 percent. Runoff from the onsite improvements that is not infiltrated onsite is conveyed to N 35th St. The proposed right-of-way improvements include a new inlet structure located in N 35th St to the west of the project site, refer to Section 5 for more information. Runoff from the site ultimately drains to Lake Washington via N 35th St and the city of Renton conveyance system. Refer to Figure 1.1 for a completed Technical Information Report Worksheet. Refer to Figures 1.2 and 1.3 for a vicinity map and an aerial photo. A survey is included in Appendix A. Utilities (power, gas, water and sewer) are available in N 35th Street. There are no known critical areas on or within 200 feet of the site. 8/2/2023 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 5 of 39 Based on the City Renton code, the 2022 Combined Renton Surface Water Design Manual (2022 CRSWDM), the City of Renton COR Maps website, King County iMap, and the survey this site is as follows: Site Address 1011 N 35th Street, Renton, WA 98056 King County Parcel No. 334210-2545 Zoning R-8 UGA Inside the Urban Growth Area CARA Outside Aquifer Protection Area Zone 2 Steep Slope/ Erosion/Landslide Hazard Areas A small portion of the project site is located in a Moderate Landslide Hazard Area. Shoreline Designation NA Lot Area 10,809 SF or 0.248 Acres per survey Onsite Slopes 1% to 8% Condition Developed, and landscaped primarily with grass, deciduous trees, as well as shrubs/bushes Critical Areas None Flow Control Not Applicable Water Quality Not Applicable ONSITE SOILS Subsurface investigation was completed by Nelson Geotechnical Associates, Inc, as documented in a project specific report dated September 20, 2022. Investigation included five test pits (TP), extending to depths in the range of 6.0 to 10.0 feet below the existing ground surface. The observed soil conditions in all explorations completed on August 25, 2022 were as follows from the surface to the termination point: At the surface, approximately 2.0 to 5.5 feet of surficial grass and loose to medium dense dark brown silty fine to medium sand was encountered. Underlying the surficial topsoil medium dense to dense, fine to medium sand with varying amounts of silt and gravel was encountered. Moderate groundwater seepage was encountered within TP 3 and 4 at depths of 9 and 7.5 feet below existing ground respectively. This groundwater seepage was interpreted to be perched groundwater which does not represent a regional groundwater “table” withing the upper soil horizons. Refer to Appendix B for a full geotechnical report. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 6 of 39 Figure 1.1 – TIR Worksheet CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Land Use (e.g., Subdivision / Short Subd.)  Building (e.g., M/F / Commercial / SFR)  Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed ____________________________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified ____________________________________ __________________ Andy Epstein, P.E. Ethos Civil (253) 579-4288 Aguilar Renton SFR X X 24 North 5 East 32 12015 NE 8th St, Ste 5 Bellevue, WA 98005 Straight Arrow Homes, LLC BLD_____ X X 1011 N 35th St, Renton, WA 98056 (425) 443-5458 08/03/2022 08/03/2022 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ East Lake Washington Core Requirement 1 - 9, Special Requirement 1 - 5; peak rate flow control standard Kennydale NA X Moderate REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ On-site BMPs: _______________________________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ East Lake Washington 1 TBD NA NA NA May 26, 2023 Permeable Pavement 2 Peak Rate Flow Control Standard Surficial Topsoil 1%-8%Low REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: NA NA #1 - AREA EXEMPTION NA SINGLE FAMILY RESIDENTIAL REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Control Pollutants  Protect Existing and Proposed BMPs/Facilities  Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary  Flag limits of sensitive areas and open space preservation areas  Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ____________________________  Cast in Place Vault  Retaining Wall  Rockery > 4′ High  Structural on Steep Slope  Other _______________________________ X X PERMEABLE PAVEMENT X X X X X X X X X X REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6 Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date 06/14/2023 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 7 of 39 Figure 1.2 – Site Location Source: mapquest.com AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 8 of 39 Figure 1.3 – Aerial Site Photo AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 9 of 39 EXISTING AND DEVELOPED CONDTIONS Development includes a 2-lot subdivision of the subject 16,200 SF lot by others and redevelopment of the west lot, which will be approximately 10,800 SF, with a new single-family residence, DADU, and access driveway to 35th Street. The existing single family development improvements will be removed in preparation for this development. The project will also include off-site improvements to include new curb and gutter, sidewalk, and 2” asphalt grind and overlay to the road centerline. Runoff from the roof areas of the proposed SFR and DADU will be collected and conveyed via roof drains and will curb discharge to the flowline of N 35th St before connecting to the City of Renton stormwater network. A small amount of runoff will also be infiltrated on-site. Refer to Figure 3.1 and Task 4 for a detailed description of the downstream flow path. Existing impervious areas and proposed impervious areas are summarized in Figure 1.4 below, followed by the Existing Conditions Map in Figure 1.5 and the Developed Basin Map in Figure 1.6. Figure 1.4 – Developed and Existing Basin Area Summary AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 10 of 39 Figure 1.5 – Existing Basin Map AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 11 of 39 Figure 1.6 – Developed Basin Map PLOTTED: 6/15/2023 2:22:07 PM FILE: _22073-STRM.DWG LAST SAVED BY: NOAHBURLINGAMEKnow what'sbelow.before you dig.CallRDATEDESCRIPTION#DESIGNEDCHECKEDDRAWNCHECKED© 2022 Ethos Civil LLC. All rights reserved. No part of this document may be reproduced in any formwithout permission from Ethos Civil LLC.ethoscivil.com info@ethoscivil.com 253.414.198944221NWBABENWBABE2207306/14/2023AGUILARRENTON SFR1011 N 35TH STREETRENTON, WA 98056PERMIT SET NSCALE IN FEET10501020FIG 1.6NSCALE IN FEET10501020DEVELOPEDBASIN MAPPROPOSED PERVIOUS:5271 SFPROPOSED ROOF AREA:4767 SFPROPOSED DRIVEWAY:1085 SFPROPOSED CONCRETEWALKWAYS, DRIVEWAYS,SIDEWALK, CURB/GUTTER,REPLACED ROAD:1330 SFRIGHT-OF-WAY DEDICATION: 150 SFGRIND AND OVERLAY: 829 SF AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 12 of 39 Section 2 – Conditions and Requirements Summary Drainage Review Type Project is subject to Direct Drainage Review per Figure 2.1 below, since it is a single-family residential project that will exceed the thresholds for simplified drainage review. Project is therefore subject to: · All nine core requirements; and · All five special requirements. Definitions from CRSWDM Section 1.1 Aquifer Protection Area (APA) means the portion of an aquifer within the zone of capture and recharge area for a well or well field owned or operated by the City of Renton delineated in the Aquifer Protection map found in the City of Renton Map Gallery (<http://rentonwa.gov/government/default.aspx?id=29885>) or viewed via COR Maps (<http://rp.rentonwa.gov/SilverlightPublic/Viewer.html?Viewer=COR-Maps>). Impervious surface means a non-vegetated surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions before development; or that causes water to run off the surface in greater quantities or at an increased rate of flow compared to the flow present under natural conditions prior to development (see also new impervious surface). Common impervious surfaces include, but are not limited to, roof, walkways, patios, driveways, parking lots, or storage areas, areas that are paved, graveled or made of packed or oiled earthen materials or other surfaces that similarly impede the natural infiltration of surface water or stormwater. For the purposes of applying the impervious surface thresholds and exemptions contained in this manual, permeable pavement, vegetated roofs, and pervious surfaces with underdrains designed to collect stormwater runoff are considered impervious surface while an open uncovered flow control or water quality facility is not. However, for the purposes of computing runoff, uncovered flow control or water quality facilities shall be modeled as impervious surfaces as specified in Chapter 3 New impervious surface means the addition of a man-made, modified, or compacted surface like roofs, pavement, gravel, or dirt; or the addition of a more compacted surface, such as resurfacing by upgrading from dirt to gravel, asphalt, or concrete; upgrading from gravel to asphalt, or concrete; or upgrading from a bituminous surface treatment (“chip seal”) to asphalt or concrete. Permeable pavement and vegetated roofs are considered new impervious surface for purposes of determining whether the thresholds for application of minimum requirements are exceeded, as are lawns, landscaping, sports fields, golf courses, and other areas that have modified runoff characteristics resulting from the addition of underdrains designed to collect stormwater runoff. Open, uncovered retention/detention facilities shall not be considered impervious surfaces for purposes of determining whether the thresholds for application of minimum requirements are exceeded. Open, uncovered retention/detention facilities shall be considered impervious surfaces for purposes of runoff modeling. New pervious surface means the conversion of a native vegetated surface or other native surface to a nonnative pervious surface (e.g., conversion of forest or meadow to pasture land, grass land, cultivated land, lawn, landscaping, bare soil, etc.), or any alteration of existing nonnative pervious surface that significantly increases surface and storm water runoff (e.g., conversion of pasture land, grass land, or cultivated land to lawn, landscaping, or bare soil; or alteration of soil characteristics). AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 13 of 39 Project means any proposed action to alter or develop a site. The proposed action of a permit application or an approval, which requires drainage review. Project site means that portion of a site and any offsite areas subject to proposed project activities, alterations, and improvements including those required by this manual. Replaced impervious surface means any existing impervious surface on the project site that is proposed to be removed and re-established as impervious surface, excluding impervious surface removed for the sole purpose of installing utilities or performing maintenance on underground infrastructure. For structures, removed means the removal of buildings down to the foundation. For other impervious surfaces, removed means the removal down to base course or bare soil. For purposes of this definition, base course is the layer of crushed rock that typically underlies an asphalt or concrete pavement. It does not include the removal of pavement material through grinding or other surface modification unless the entire layer of PCC or AC is removed. Replaced impervious surface also includes impervious surface that is moved from one location to another on the project site where the following two conditions are met: (A) runoff characteristics and volumes remain the same or are improved in the area where the existing impervious surface is removed , and (B) impervious surface at the new location is either designated as non-pollution generating or the pollution generating characteristics remain unchanged compared to that of the original location. Site means a single parcel; or, two or more contiguous parcels that are under common ownership or documented legal control; or a portion of a single parcel under documented legal control separate from the remaining parcel, used as a single parcel for a proposed project for purposes of applying for authority from the City to carry out a proposed project. For projects located primarily within dedicated rights-of-way, the length of the project site and the right-of-way boundaries define the site. Target surface area means a developed surface from which runoff impacts are required to be mitigated by a particular set of drainage requirements. Target impervious surface means that portion of a site’s new and/or replaced impervious surface from which runoff impacts are required to be mitigated by a particular set of drainage requirements (flow control facility, water quality facility, and/or on-site BMP). AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 14 of 39 Figure 2.1 – Renton Surface Water Design Manual Flow Chart for Determining Type of Drainge Review Required AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 15 of 39 Core Requirement #1: Discharge at the Natural Location Runoff from the proposed development will continue to discharge to N 35th St, which is the natural discharge location for this site. The site is not within a mapped landslide hazard area. Refer to the Level 1 Downstream Analysis under Section 3 of this TIR for a complete description of the downstream drainage system. Core Requirement #2: Offsite Analysis Core Requirement #2 is applicable to the entire project per CRSWDM Section 1.2.2. An offsite analysis is provided in Section 3 of this report. Core Requirement #3: Flow Control Per CRSWDM Section 1.2.3, this project does not meet the basic exemption from flow control since it does not result in less than 5,000 Sf of new plus replaced impervious surface area. Per the City of Renton Flow Control Applications Map, adopted in Reference Section 15-A of the CRSWDM (which may also be viewed via COR Maps online), this project site is under the Peak Rate Flow Control Standard – ‘Matching Existing site conditions 2, 10 and 100-year peak-rate runoff for areas draining to constructed (man-made) or highly modified drainage systems so as not to create a downstream flooding problem.’ Per Section 1.2.3.1.A (CRSWDM pg. 1-40), the following exceptions (exception #2) applies only in the Peak Rate Flow Control Standard Areas: Runoff from the target surfaces will increase 100-year flows less than 0.15 cfs (when modeled using 15- minute time steps) compared to the existing. The project will result in a slight net increase in cfs for the 100-year compared to the existing flows. Refer to Section 4 for additional detail. Core Requirement #4: Conveyance System Core requirement #4 is applicable to the project. The on-site conveyance system is limited to the roofdrain network which directs runoff to a curb discharge point. The off-site conveyance improvements include the downstream inlet replacement and the proposed storm main which spans the length of the project site’s frontage. Refer to Section 5 for further information about the off-site improvements. Core Requirement #5: CSWPP Core Requirement #5 is applicable to the project per CRSWDM Section 1.2.5. Temporary erosion and sediment control (TESC) plans providing details on best management practices (BMPs) to be implemented during construction are included for each building permit application. Refer to Section 8 for the remainder of the Construction Stormwater Pollution Prevention Analysis and Design, including Stormwater Pollution Prevention and Spill (SWPPS) measures. Core Requirement #6: Maintenance and Operations Core Requirement #6 is applicable to the project per CRSWDM Section 1.2.6. Operation and maintenance information is provided in Appendix C. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 16 of 39 Core Requirement #7: Financial Guarantees and Liability The owner will provide any financial guarantees and liabilities required by the right-of-way permit. Core Requirement #8: Water Quality Facilities Core Requirement #8 is not applicable to the project per the Surface Area Exemption #1 in CRSWDM Section 1.2.8. The improvements include less than 5,000 square feet of new or replaced pollution- generating impervious surfaces (PGIS). Core Requirement #9: Flow Control BMPs Core Requirement #9 is applicable per 2022 CRSWDM Section 1.2.9 since it includes more than 2,000 of new plus replaced impervious surface area. This project is subject to 1.2.9.2.1/Appendix C1.3.1 Small Lot BMP Requirements, since the site is smaller than 22,000 SF. Flow control BMPs must be applied as specified in this section, or the project must demonstrate compliance with the Low Impact Development (LID) Performance Standard (described in Section 1.2.9 of the 2022 CRSWDM ); the former option was evaluated for this project. Per Section 1.2.9.1.A, Target surfaces for Core Requirement #9 include new impervious surfaces, new pervious surfaces, replaced impervious surfaces, and any existing impervious surfaces added on or after January 8, 2001, not already mitigated with an approved Flow Control BMP or flow control facility. Interpretation: · New impervious surfaces are a target surface for this project and need to be mitigated with a FCBMP or flow control facility. This project does not include any replaced impervious surfaces. · New pervious surfaces are a target surface for this project. Per 2022 CRSWDM , new pervious surfaces are defined as the conversion of a native vegetated surface or other native surface to a non-native pervious surface (e.g., conversion of forest or meadow to pasture land, grass land, cultivated land, lawn, landscaping, bare soil, etc.), or any alteration of existing non-native pervious surface that significantly increases surface and storm water runoff (e.g., conversion of pasture land, grass land, or cultivated land to lawn, landscaping, or bare soil; or alteration of soil characteristics). The disturbed landscape area is not considered a new pervious surface since the existing pervious surface is lawn and are not considered forested or meadow. Below is a site-specific evaluation of the required BMPs per Section 1.2.9.2.1 of the CRSWDM: 1. Requirement 1 – Full dispersion per (Appendix) C.2.1.1: infeasible since the 100 feet of native vegetated flow path is not available onsite. 2. Requirement 2 – Full infiltration of roof runoff per C.2.2: infiltration is not feasible due to and the minimum vertical separation to groundwater cannot be met. 3. Requirement 3: a. Full infiltration per C.2.2 or Section 5.2: infeasible for the same reasons discussed under requirement 2 above. b. Limited infiltration per C.2.3: This BMP is infeasible for the same reasons discussed under requirement 2 above. c. Bioretention per C.2.6: This BMP is infeasible for the same reasons discussed under requirement 2 above. d. Permeable Pavement per C.2.7: Feasible. The project proposes utilizing this permeable pavement since the vertical separation to groundwater can be met. This BMP addresses the requirement noted below in Part 5 of this section since over 10% of the target impervious area is mitigated. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 17 of 39 4. Requirement 4 – Basic Dispersion per C.2.4: infeasible as the project does not have adequate space to provide basic dispersion. 5. Requirement 5 – Minimum BMP Implementation: 10% of the impervious area must be mitigated with FCBMPs as the lot is considered a small lot that is less than 11,000 SF and is outside of the wellhead protection zone 1. As shown in Figure 1.4, this requirement is met since over 10% of the target impervious area is mitigated. 6. Requirement 6 – Protect soil moisture capacity of new pervious surfaces Maintaining topsoil and/or amending soils is required for disturbed and new pervious areas. Areas to be protected and amended are identified on the Erosion and Sediment Control Plan Site Map. 7. Requirement 7 – Perforated Downspouts This BMP is infeasible since the minimum vertical separation requirement cannot be met due to the presence of shallow perched groundwater. Special Requirement #1: Other Adopted Areas-Specific Requirement Special Requirement #1 is not applicable to the project per CRSWDM Section 1.3.1, as there are no other adopted area-specific requirements. Special Requirement #2: Flood Hazard Area Delineation Special Requirement #2 is not applicable to the project per CRSWDM Section 1.3.2, as the site is not located in or adjacent to the 100-year flood plain. Special Requirement #3: Flood Protection Facility Special Requirement #3 is not applicable to the project per CRSWDM Section 1.3.3. The project site does not rely on an existing flood protection facility (such as a levee or revetment) for protection against hazards, nor does the project site modify or construct a new flood protection facility. Special Requirement #4: Source Control Special Requirement #4 is not applicable to the project per CRSWDM Section 1.3.4 since this is a single- family residential project. Special Requirement #5: Oil Control Special Requirement #5 is not applicable to the project per CRSWDM Section 1.3.5, as this project site does not have characteristics of a high-use site, nor is it an existing high-use site. Per the CRSWDM, a high- use site is defined as a commercial or industrial site that (1) has an expected average daily traffic (ADT) count equal to or greater than 100 vehicles per 1,000 square feet or gross building area; (2) is subject to petroleum storage or transfer in excess of 1,500 gallons per year, not including delivered heating oil; or (3) is subject to use, storage, or maintenance of a fleet of 25 or more diesel vehicles that are over 10 tons net weight (trucks, buses, trains, heavy equipment, etc.). For this definition, commercial and industrial site means that portion of a site’s developed area associated with an individual commercial or industrial business. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 18 of 39 Special Requirement #6: Aquifer Protection Area Special Requirement #6 is not applicable to the project per CRSWDM Section 1.3.6 since the site is located just outside of Wellhead Protection Area – Zone 2. If the project were within this zone, Per CRSWDM liners are required for open flow control facilities, such as ponds, as well as conveyance ditches that will convey pollution generating surfaces. No such facilities are proposed for this development; therefore, the liner requirement is not applicable. Section 3 – Offsite Analysis A Level 1 Analysis of the downstream conditions has been completed, per Core Requirement #2, Section 1.2.2 of 2017 CRSWDM. As required, both downstream and upstream conditions were analyzed qualitatively. TASK 1 – Define and Map the Study Area The study area includes N 35th St from the project site approximately a quarter mile downstream where the City of the Renton stormwater conveyance system discharges into Lake Washington. A downstream map is provided in Figure 3.1 below. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 19 of 39 Figure 3.1 – Downstream Map 2,257 188 City of Renton Print map Template This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 6/12/2023 Legend 128064 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 128 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov Network Structures Public Access Riser Private Access Riser Public Inlet Private Inlet Public Manhole Private Manhole Public Utility Vault Private Utility Vault Public Clean Out Private Clean Out Public Unknown Private Unknown Pump Station Public Pump Station Private Pump Station Discharge Point Public Discharge Point Private Discharge Point Water Quality Public Water Quality Private Water Quality Detention Facilities Public Detention Facility Private Detention Facility Pipe PROJECT SITE Possible discharge point to Lake Washington Possible Flow Paths Stormwater enters city conveyance system at catch basin in N 35th ST Stormwater curb discharges into flowline of N 35th ST Possible discharge point to Lake Washington Photo A Photo B Photo C AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 20 of 39 TASK 2 – Review All Available Information on the Study Area The City of Renton COR Maps website as well as King County iMap were reviewed for the surrounding and downstream study area. Based on King County iMap there are no drainage complaints for this area. Based on City of Renton COR Map, there are moderate to high landslide hazard areas within the downstream study area, as shown in Figure 3.2. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 21 of 39 Figure 3.2 – City of Renton Critical Areas Map 4,514 376 City of Renton Critical Areas Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 3/7/2023 Legend 2560128 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 256 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Labels Addresses Parcels City and County Boundary <all other values> Renton Wellhead Protection Area Zones Zone 1 Zone 1 Modified Zone 2 Erosion Hazard - High Floodway Special Flood Hazard Areas (100 year flood) year flood)Landslide Very High High Moderate Unclassified Environment Designations Natural Shoreline High Intensity Shoreline Isolated High Intensity Shoreline Residential Urban Conservancy Jurisdictions Streams (Classified) Moderate Landslide Hazard Area, Typ. PROJECT SITE High Landslide Hazard Area, Typ. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 22 of 39 TASK 3 – Field Inspect the Study Area A field investigation was completed by Ethos Civil on May 26, 2023, as part of the downstream analysis. The onsite drainage patterns within the project site were observed. Refer to Task 4 below for a detailed description of the downstream drainage system and analysis. TASK 4 – Describe the drainage system, and its existing and predicted drainage and water quality problems. Runoff from the site, including runoff from the onsite lawn, driveway, walks and roof runoff, drains north into N 35th Street. N 35th Street is a crowned road that does not include a piped conveyance system adjacent to the proposed project. Instead, runoff in the street is conveyed via gutter flow via the asphalt wedge curb west to a public catch basin, just east of the intersection of N 35th Street and Burnette Ave N. Runoff from the south side of 35th is collected in the aforementioned catch basin (shown in Photo C), before being conveyed west via 12” pipe and another catch basin to the corner of Burnett Ave N and N 35th St. Runoff then crosses Burnett Ave N via 12” concrete pipe. Runoff is then either directed to the north via drainage ditch and 24” concrete pipe to an outfall at Kennydale Beach Park (Photo E), or to the south via pipes, manholes and catch basins to an outfall on parcel number 3124059076. No storm drainage system or flooding problems system problems were observed during the visit. Neither were any erosion or landslide hazard concerns observed. Photographs from the site visit are included below and the letters correspond to the letters indicated on Figure 3.1. Photo A – N 35th St, Adjacent to the project site, looking West: AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 23 of 39 Photo B – N 35th St, mid-block, looking West: AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 24 of 39 Photo C – South side of N 35th ST, East of intersection w/ Burnette Ave N, drainage inlet: AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 25 of 39 Photo D – Discharge to Lake Washington at Kennydale Beach Park AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 26 of 39 Section 4 – Flow Control, LID and WQ Facility Analysis and Design PART A: EXISTING SITE HYDROLOGY The existing development was modeled in WWHM 2012 per the areas described and delineated in Section 1, Figure 1.5. In the WWHM model, this basin was assigned Point of Compliance 1 (POC 1) for comparing to the developed runoff condition. PART B: DEVELOPED SITE HYDROLOGY The developed conditions were modeled per Section 1, see Figure 1.6 for the developed basin map detailing impervious tributary areas for the project. The fully developed condition, including the street improvements were modeled in WWHM 2012 and assigned POC 1 for comparing to the existing conditions to verify that the project is exempt from flow control. PART C: PERFORMANCE STANDARDS The LID performance standard is not feasible for the project due to high groundwater making full infiltration infeasible. However, shallow infiltration associated with permeable pavement is feasible and is utilized for the proposed project. PART D: FLOW CONTROL SYSTEM Per CRSWDM Section 1.2.3, this project does not meet the basic exemption from flow control since it does not result in less than 5,000 Sf of new plus replaced impervious surface area. Per the City of Renton Flow Control Applications Map, adopted in Reference Section 15-A of the CRSWDM (which may also be viewed via COR Maps online), this project site is under the Peak Rate Flow Control Standard – ‘Matching Existing site conditions 2, 10 and 100-year peak-rate runoff for areas draining to constructed (man-made) or highly modified drainage systems so as not to create a downstream flooding problem.’ Per Section 1.2.3.1.A (CRSWDM pg. 1-40), the following exceptions (exception #2) applies only in the Peak Rate Flow Control Standard Areas: Runoff from the target surfaces will increase 100-year flows less than 0.15 cfs (when modeled using 15- minute time steps) compared to the existing. Per the WWHM Model and Figures 4.1 below, the existing and developed 100-year peak flows are 0.1292 cfs and 0.1427 cfs, respectively. Refer to Appendix E for a copy of the full WWHM data output. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 27 of 39 Figure 4.1 – Existing vs Developed Peak Flows (POC 1) PART E: WATER QUALITY SYSTEM Core Requirement #8 is not applicable to the project per the Surface Area Exemption #1 in CRSWDM Section 1.2.8. The improvements include less than 5,000 square feet of new or replaced pollution- generating impervious surfaces (PGIS). AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 28 of 39 Section 5 – Conveyance System Analysis and Design Offsite N 35th St Inlet Design Included in the proposed right-of-way improvements is a new inlet structure on the south side of N 35th St, near the intersection of N 35th St and Burnett Avenue N. The WSDOT 2019 Inlet Spacing – Curb and Gutter (hereinafter referred to as the spreadsheet), and the WSDOT Hydraulics Manual were used to design this new inlet structure. Refer to Appendix F for calculations, as well as a basin map depicting the area that will drain to the prosed inlet. Peak flow for the 10-year and 100-year SBUH Type 1A storm events were determined using AutoCAD Storm and Sanitary Analysis (SSA). Flows for this analysis were calculated assuming full build-out for N 35th St as well as residential lots with the maximum allowable impervious percentage of 65% based on Renton Municipal Code (RMC) 4-2-110A. Refer to Appendix F for an upstream basin map, WSDOT spreadsheet and SSA output. The final design includes replacement of the existing Type 1 Catch Basin with a Type 2 Catch Basin structure and a dual vaned grate that will be rotated perpendicular to the flow line. 6” tall asphalt wedge curb is proposed instead of curb and gutter. The cross section of a wedge curb will function better with the existing improvements and provide more conveyance capacity because of its larger overall cross section from the sloping curb; since the Spreadsheet was setup for curb and gutter, which has a vertical curb, the design is more conservative than the analysis shows. The road at this location will have approximately a 7% longitudinal slope and a 3. 5% cross slope. The catch basin and grate were located to utilize the existing drainage pipe alignment and to avoid existing utilities. The final configuration locates the outside edge of frame for the dual vaned grate approximately 6-ft south of the existing road flow line. For the 100-year storm event, per the spreadsheet, the width of the flow (Zd) will be less than 5-ft and will therefore be fully captured by the new inlet. An additional 3” tall asphalt curb is proposed at the existing flow line location on the surface of the pavement to capture flows that might otherwise bypass. Per the WSDOT Hydraulics Manual, " The last inlet on a continuous run of curb (that is not a sag or flanking inlet) is permitted to bypass a maximum of 0.10 cfs for the 10-year MRI storm. The bypass flow rate of 0.1 cfs will not usually cause erosion or hydroplaning problems." Additionally, per the WSDOT Hydraulics Manual, " The last inlet on a continuous run of curb (that is not a sag or flanking inlet) is permitted to bypass a maximum of 0.10 cfs for the 10-year MRI storm. The bypass flow rate of 0.1 cfs will not usually cause erosion or hydroplaning problems." These is requirement is met for 10-year as well as for the 100-year, with bypass flows (Qbp) of 0.01 and 0.07 cfs, respectively. Additionally, regarding flow spread, the design provides for a full 13-ft lane down the center of the road. This is confirmed by the Zd check, where Zd allowable is greater than Zd design. Offsite N 35th St Storm Main Also included in the proposed right-of-way improvement across the project frontage is a 12” dry storm pipe connected to a Type 2 catch basin with a solid, locking lid. These improvements have been designed to support future development to include a full storm extension along N 35th Street. The off- site civil plans also include a conceptual design for a connection from the proposed Type 2 catch basin to the new inlet structure described in the previous section. This conceptual design is depicted in the civil site plan and includes a network of 12” conveyance pipes and catch basins. An SSA model was prepared to demonstrate that the proposed storm main--and the conceptual future connection—are sufficiently sized, refer to Appendix G for a full SSA output and a basin map. The model accounted for a total basin area of 7.62 acres, covering both the north and south side of the entire length of N 35th St. The basin was calculated to have an impervious cover of 79.6%, assuming the maximum allowable impervious percentage of 75% for the residential lots and 100% impervious coverage of the right-of-way. The 25-yr AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 29 of 39 storm was used for design as specified in Section 1.2.4.1 of the CRSWDM. The calculated design flow capacity of the section of storm main with the lowest flow capacity was 4.37 cfs, and the peak calculated flow for the 25-yr storm was 4.21 cfs, which demonstrates sufficient conveyance capacity throughout the network. Section 6 – Special Reports and Studies No further reports or studies are anticipated. Section 7 – Other Permits The following permits are anticipated: Building permits, a right-of-way permit, a civil permit, and an on- site drainage permit, all from the City of Renton. Section 8 – Construction Stormwater Pollution Prevention Analysis and Design A Construction Stormwater Control Plan following Best Management Practice’s (BMP’s) will be implemented during construction. Following is a summary of some of the BMPs that will be used. The CSWPP Supervisor is the responsible person who will oversee implementation and maintenance. Refer to the plans for proposed construction sequence as well as the CSWPPP that has been prepared for this project. Erosion and Sediment Control (ESC) Measures The following ESC measures are required to minimize erosion and sediment transport offsite: 1. Limits of Disturbance will be marked by fencing or other means on the ground; this will be completed prior to land disturbing activity to protect vegetated areas which do not need to be disturbed with the proposed improvements. 2. Straw, mulch or plastic will be used to cover the site or to provide immediate temporary/short- term protection from erosion. 3. Perimeter Protection: A row of siltation fence is on the downhill sides of the project area; this BMP was selected to provide perimeter protection since site grades will not concentrate flows and site slopes are shallow (less than 10%, which allows for a maximum flow path of up to 250 feet). Flow path lengths max out at about 100 feet. 4. Traffic Area Stabilization: The existing driveway may be used a as stabilized construction exit in lieu of constructing a construction exist. A stabilized exit is required to prevent the tracking sediment offsite. 5. Catch Basin Inserts, which are manufactured device made of filter fabric and nests inside a catch basin, will be placed on catch basin until the site is fully stabilized. This BMP was selected to prevent coarse sediment from entering the storm drainage system and because the contributing basin area to the catch basin are small (significantly less than one acre). 6. Surface Water Collection: Not anticipated during construction. If surface water is collected it should be dispersed across established vegetation. 7. Dewatering: Accumulated water in foundation areas, excavations, and utility trenches shall be removed and disposed of in a manner that does not pollute surface waters or cause downstream erosion or flooding. See "Dewatering Control," Section D.2.1.7 (p. D-66), for detailed specifications. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 30 of 39 8. Dust Control: Not anticipated. 9. Flow Control: Not applicable since this is a small project site. 10. Control Pollutants: Refer to SWPPS Measures below. 11. Maintain BMPs: BMPs will be maintained by the CSWPP Supervisor or designee per the Renton Surface Water Design manual or DOE BMPs. All BMPs implemented on site must be maintained and repaired until after the site is completely stabilized in order to protect the function of the BMP in erosion control practice. 12. Manage Project: o Site demolition and grading shall be performed after the erosion and sediment control measures have been constructed. o Trenches shall be opened only immediately prior to installation of the stormwater conveyance pipes and the trenches should be backfilled immediately after any required testing or inspections of the installed pipes. Trenching spoils must be treated as other disturbed earthwork and measures should be taken to cover or otherwise stabilize the material, as required. o The Construction SWPPP plan shall be retained on-site or within reasonable access to the site at all times. The CSWPPP plan shall be modified to include any additional or modified BMPs that are deemed necessary to manage erosion and sediment on the site. Revisions to the CSWPPP must be completed within seven days. o Report spillage or discharge of pollutants within 24-hours to the City of Renton. 13. Protect Low Impact Development BMPs: This project includes the following low impact development features and the following protection requirements apply: · Permeable Pavers: the installation of permeable pavers must be completed at the end of the project to protect the system from sediment. Furthermore, underlying soils in these areas must be protected from over compaction. Flags or fencing will be used to protect these areas. Stormwater Pollution Prevention and Spill (SWPPS) Measures The following SWPPS measures are required to prevent, reduce or eliminated the discharge of pollutants to onsite or adjacent stormwater systems from construction related activities. 1. Follow effective pollutant handling and disposal procedures. All pollutants, including waste materials and demolition debris that occur on-site during construction shall be handled and disposed of in a manner that does not cause contamination of stormwater. This is necessary to protect site soils and Lake Washington (downstream) and to comply with regulations. 2. Provide cover and containment for materials, fuel and other pollutants. This measure is necessary to protect onsite soils and Lake Washington from petroleum products, asphalt and concrete compounds, hazardous chemicals, etc. A centralized area for storage and maintenance and refueling of construction equipment must be provided onsite and away from Lake Washington. This is anticipated to be provided onsite near the site entrance (away from Lake Washington) at the beginning of construction and may be within the house after the roof is installed. Refer to CRSWDM D.2.2.4 for more specific requirements. 3. Manage the project site to maximize pollutant control and minimize pollutant sources. Control of pollutants other than sediments is the responsibility of the CSWPP Supervisor. This oversight of subcontractors and laborer is important to keep the project on track with SWPPS and ESC measures. A CSWPP Supervisor is identified on the plan and will be the primary contact responsible for SWPPS and ESC issues and reporting, coordination with subcontractors and implementation of the CSWPP Plan. Refer to CRSWDM D.2.2.11 for more specific requirements. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 31 of 39 4. Protect from spills and drips of petroleum products and other pollutants. This is important since the project drains to a system that discharges to Lake Washington. 5. Avoid overapplication or untimely application of chemicals and fertilizers. This is important since the project drains to a system that discharges to Lake Washington. 6. Prevent or treat contamination of stormwater runoff by pH modifying sources. o Concrete Handling will be employed since this site includes concrete foundation, driveway and walks. Below is a list of pertinent the Design and Installation Specifications from CRSWDM: 1. Assure that washout of concrete trucks, chutes, pumps, and internals is performed at an approved off-site location or in designated concrete washout areas. Do not wash out concrete trucks onto the ground, or into storm drains, open ditches, streets, or streams. Refer to BMP D.2.2.2 for information on concrete washout areas. 2. Return unused concrete remaining in the truck and pump to the originating batch plant for recycling. Do not dump excess concrete on site, except in designated concrete washout areas. 3. Wash off hand tools including, but not limited to, screeds, shovels, rakes, floats, and trowels into formed areas only. 4. Wash equipment difficult to move, such as concrete pavers in areas that do not directly drain to natural or constructed stormwater conveyances. 5. Do not allow washdown from areas, such as concrete aggregate driveways, to drain directly to natural or constructed stormwater conveyances. 6. Contain wash water and leftover product in a lined container when no formed areas are available. Dispose of contained concrete in a manner that does not violate ground water or surface water quality standards. 7. Concrete Washout Area will be employed offsite. The developer is planning for washout of concrete trucks to be completed at an approved off-site location, since this is a small lot. Refer to RSDWM D.2.2.2 for specifications, details and maintenance standards. Refer to RSDWM D.2.2. for additional specifications, details and maintenance standards. Section 9 – Bond Quantities, Facility Summaries, and Declaration of Covenant A Declaration of Covenant will be required for individual lot BMPs to address protection and maintenance of BMPs. This has been completed for each lot and is included in Appendix C. Section 10 – Operations and Maintenance Manual An operations and maintenance manual has been prepared and is provided in Appendix D. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 32 of 39 APPENDICES AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 33 of 39 APPENDIX A – SURVEY AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 34 of 39 APPENDIX B – GEOTECHNICAL REPORT NELSON GEOTECHNICAL ASSOCIATES, INC. September 20, 2022 Gary and Kaci Aguilar 1011 North 35th Street Renton, Washington 98056 VIA Email: garyaguilar@msn.com kaciaguilar79@gmail.com Geotechnical Engineering Evaluation Aguilar North 35th Street Residence Development 1011 North 35th Street Renton, Washington NGA File No. 1388322 Dear Mr. and Mrs. Aguilar: We are pleased to submit the attached report titled “Geotechnical Engineering Evaluation – Aguilar North 35th Street Residence Development – 1011 North 35th Street – Renton, Washington.” This report summarizes our observations of the existing surface and subsurface conditions within the site and provides general recommendations for the proposed site development. Our services were completed in general accordance with the proposal signed by you on August 1, 2022. The property is currently occupied with an existing single-family residence with a detached garage within the central and southeastern portions of the property. The ground surface within the property generally slopes gently down from the southeast to the northwest. We understand that the proposed development will include removal of the existing single-family residence and constructing a new single- family residence and associated detached accessory dwelling unit (DADU) within the central and south- central portion of the property, respectively. The existing garage within the southeastern portion of the property is to remain. We explored the subsurface conditions within the site with five trackhoe excavated test pits explorations. The explorations extended to depths in the range of 6.0 to 10.0 feet below the existing ground surface. Our explorations indicated that the site was underlain by surficial undocumented fill soils with competent native glacial outwash soils at depth. It is our opinion that the proposed site development is feasible from a geotechnical engineering standpoint, provided that our recommendations for site development are incorporated into project plans. In general, the native glacial bearing soils underlying the site should adequately support the planned structures. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Summary – Page 2 NELSON GEOTECHNICAL ASSOCIATES, INC. Foundations should be advanced through any loose and/or undocumented fill soils down to the competent glacial bearing material interpreted to underlie the site, for bearing capacity and settlement considerations. These soils should generally be encountered between approximately 2.0 to 5.5 feet below the existing ground surface, based on our explorations. The deepest area of undocumented fill was generally encountered within the north-central portion of the property. If deeper areas of loose soils or undocumented fill are encountered in unexplored areas of the site, they should be removed and replaced with structural fill for foundation and pavement support. Specific grading and stormwater plans have not been finalized at the time this report was prepared. However, we understand that stormwater from the proposed development may be directed into on-site infiltration systems, if feasible. The City of Renton uses the 2022 City of Renton Surface Water Design Manual to determine the design of infiltration facilities. According to this manual and the City of Renton requirements, on-site infiltration testing consisting of the small Pilot Infiltration Test (PIT) is used to determine the long-term design infiltration rates. Based on the results of our on-site infiltration testing, it is our opinion that the onsite native outwash soils within the property are marginally feasible for stormwater infiltration. This is discussed in more detail in the attached report. In the attached report, we have also provided general recommendations for site grading, slabs-on- grade, structural fill placement, retaining walls, erosion control, and drainage. We should be retained to review and comment on final development plans and observe the earthwork phase of construction. We also recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed during construction differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. It has been a pleasure to provide service to you on this project. Please contact us if you have any questions regarding this report or require further information. Sincerely, NELSON GEOTECHNICAL ASSOCIATES, INC. Khaled M. Shawish, PE Principal Engineer NELSON GEOTECHNICAL ASSOCIATES, INC. TABLE OF CONTENTS INTRODUCTION .......................................................................................................... 1 SCOPE......................................................................................................................... 1 SITE CONDITIONS ........................................................................................................ 2 Surface Conditions ........................................................................................................ 2 Subsurface Conditions .................................................................................................. 2 Hydrogeologic Conditions............................................................................................. 3 SENSITIVE AREA EVALUATION ..................................................................................... 3 Seismic Hazard .............................................................................................................. 3 Erosion Hazard .............................................................................................................. 4 CONCLUSIONS AND RECOMMENDATIONS .................................................................. 4 General ......................................................................................................................... 4 Erosion Control ............................................................................................................. 5 Site Preparation and Grading ....................................................................................... 6 Temporary and Permanent Slopes ............................................................................... 7 Foundations .................................................................................................................. 8 Retaining Walls ............................................................................................................. 9 Structural Fill ............................................................................................................... 10 Slab-on-Grade ............................................................................................................. 11 Pavements .................................................................................................................. 11 Utilities ........................................................................................................................ 11 Site Drainage ............................................................................................................... 12 CONSTRUCTION MONITORING .................................................................................. 14 USE OF THIS REPORT ................................................................................................. 14 LIST OF FIGURES Figure 1 – Vicinity Map Figure 2 – Site Plan Figure 3 – Soil Classification Chart Figures 4 and 5 – Exploration Logs NELSON GEOTECHNICAL ASSOCIATES, INC. Geotechnical Engineering Evaluation Aguilar North 35th Street Residence Development 1011 North 35th Street Renton, Washington INTRODUCTION This report presents the results of our geotechnical engineering investigation and evaluation of the planned residence development project in Renton, Washington. The project site is located at 1011 North 35th Street, as shown on the Vicinity Map in Figure 1. The purpose of this study is to explore and characterize the site’s surface and subsurface conditions and to provide geotechnical recommendations for the planned site development. The property is currently occupied with an existing single-family residence with a detached garage within the central and southeastern portions of the property. The ground surface within the property generally slopes gently down from the southeast to the northwest. We understand that the proposed development will include removal of the existing single-family residence and constructing a new single-family residence and associated detached accessory dwelling unit (DADU) within the central and south-central portion of the property, respectively. The existing garage within the southeastern portion of the property is to remain. Final development and grading plans have not been prepared at the time this report was issued. Final stormwater plans have also not been developed; however, we understand that stormwater may be directed to on-site infiltration systems, if feasible. The existing site layout is shown on the Site Plan in Figure 2. SCOPE The purpose of this study is to explore and characterize the site surface and subsurface conditions and provide general recommendations for site development. Specifically, our scope of services included the following: 1. Review available soil and geologic maps of the area. 2. Explore the subsurface soil and groundwater conditions within the site with trackhoe excavated test pits. Trackhoe was subcontracted by NGA. 3. Perform grain-size sieve analysis on soil samples, as necessary. 4. Provide recommendations for structure foundations. 5. Provide recommendations for earthwork. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 2 NELSON GEOTECHNICAL ASSOCIATES, INC. 6. Provide recommendations for temporary and permanent slopes. 7. Provide recommendations for retaining walls. 8. Provide recommendations for slab and pavement subgrade preparation. 9. Provide recommendations for utility installation. 10. Provide long-term design infiltration rates based on on-site Pilot Infiltration Testing (PIT) per the 2022 City of Renton Surface Water Design Manual. Water for the test was provided by the client. 11. Provide recommendations for infiltration system installation. 12. Provide recommendations for site drainage and erosion control. 13. Document the results of our findings, conclusions, and recommendations in a written geotechnical report. SITE CONDITIONS Surface Condition The site consists of a roughly rectangular-shaped parcel covering approximately 0.37 acres. The property is currently occupied with an existing single-family residence with a detached garage within the central and southeastern portions of the property. The ground surface within the property generally slopes gently down from the southeast to the northwest. The site is generally vegetated by grass-covered yard areas, young to mature trees, and landscaping. The property is bound to the north by North 35th Street, and to the east, south, and west by single-family residence properties. We did not observe surface water within the site during our site visit on August 25, 2022. Subsurface Conditions Geology: The geologic units for this site are shown on Preliminary Geologic Map of Seattle and Vicinity, Washington, by Waldron, H.H., Leisch, B.A., Mullineaux, D.R., and Crandell, D.R., (USGS, 1961). The site is mapped as younger sand (Qys). The younger sand deposits are described as fine to coarse sand that contains varying amounts of gravel. Our explorations generally encountered surficial topsoil and/or undocumented fill underlain by fine to medium sand with varying amounts of silt and gravel consistent with the description of younger sand deposits at depth. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 3 NELSON GEOTECHNICAL ASSOCIATES, INC. Explorations: The subsurface conditions within the site were explored on August 25, 2022 by excavating five test pits with a mini-trackhoe extending to depths in the range of 6.0 to 10.0 feet below the existing ground surface. The approximate locations of our explorations are shown on the Site Plan in Figure 2. A geologist from NGA was present during the explorations, examined the soils and geologic conditions encountered, obtained samples of the different soil types, and maintained logs of the test pits. The soils were visually classified in general accordance with the Unified Soil Classification System, presented in Figure 3. The logs of our explorations are attached to this report and are presented as Figures 4 and 5. We present a brief summary of the subsurface conditions in the following paragraph. For a detailed description of the subsurface conditions, the logs of the explorations should be reviewed. At the surface of all of our explorations, we encountered approximately 2.0 to 5.5 feet of surficial grass and loose to medium dense dark brown silty fine to medium sand with varying amounts of gravel, organics and debris that we interpreted as surficial topsoil and/or undocumented fill soils. Underlying the surficial topsoil/undocumented fill soils within all of our test pits, we encountered medium dense to dense, fine to medium sand with varying amounts of silt and gravel that we interpreted as native younger sand deposits. All of our test pits were terminated within the native younger sand soils at depths in the range of 6.0 to 10.0 feet below the existing ground surface. Hydrogeologic Conditions We encountered moderate groundwater seepage within Test Pits 3 and 4 at depths of 9.0 and 7.5 feet below the existing ground surface. We interpreted this groundwater seepage to be perched groundwater. Perched water occurs when surface water infiltrates through less dense, more permeable soils and accumulates on top of a relatively low permeability material. Perched water does not represent a regional groundwater "table" within the upper soil horizons. Perched water tends to vary spatially and is dependent upon the amount of rainfall. We would expect the amount of perched groundwater to decrease during drier times of the year and increase during wetter periods. SENSITIVE AREA EVALUATION Seismic Hazard We reviewed the 2018 International Building Code (IBC) and the ASCE 7-16 for seismic site classification for this project. Since competent glacial outwash soils were encountered at depth within the subject site, the site conditions best fit the IBC description for Site Class D. Table 1 below provides seismic design parameters for the site that are in conformance with the 2018 IBC, which specifies a design earthquake having a two percent probability of occurrence in 50 years (return interval of 2,475 years), and the 2014 USGS seismic hazard maps. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 4 NELSON GEOTECHNICAL ASSOCIATES, INC. Table 1 – ASCE 7-16 Seismic Design Parameters Site Class Spectral Acceleration at 0.2 sec. (g) Ss Spectral Acceleration at 1.0 sec. (g) S1 Site Coefficients Design Spectral Response Parameters Fa Fv SDS SD1 D 1.448 0.498 1.00 Null 0.965 Null The spectral response accelerations were obtained from the USGS Earthquake Hazards Program Interpolated Probabilistic Ground Motion website (2008 data) for the project latitude and longitude. Hazards associated with seismic activity include liquefaction potential and amplification of ground motion. Liquefaction is caused by a rise in pore pressures in a loose, fine sand deposit beneath the groundwater table. It is our opinion that the medium dense or better glacial outwash deposits interpreted to underlie the site and nearby vicinity have a low potential for liquefaction or amplification of ground motion. Erosion Hazard The criteria used for determination of the erosion hazard for affected areas include soil type, slope gradient, vegetation cover, and groundwater conditions. The erosion sensitivity is related to vegetative cover and the specific surface soil types, which are related to the underlying geologic soil units. The Soil Survey of King County Area, Washington, by the Natural Resources Conservation Service (NRCS), was reviewed to determine the erosion hazard of the on-site soils. The surface soils for this site were mapped as Indianola loamy sand, 5 to 15 percent slopes. The erosion hazard for this material is listed as slight. This site is relatively level to gently sloping and there are no steep slopes on the property. It is our opinion that the erosion hazard for site soils should be low in areas where the site is not disturbed. CONCLUSIONS AND RECOMMENDATIONS General It is our opinion that the planned development within the site is generally feasible from a geotechnical standpoint. Our explorations indicated that the site is generally underlain by competent native glacial outwash soils at depth throughout the site. The native glacial bearing soils encountered at depth should provide adequate support for foundation, slab, and pavement loads. We recommend that the planned structure be designed utilizing conventional shallow foundations. Footings should extend through any loose soil or undocumented fill soils and be founded on the underlying medium dense or better native glacial outwash soils, or structural fill extending to these soils. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 5 NELSON GEOTECHNICAL ASSOCIATES, INC. The medium dense or better native glacial bearing soils should typically be encountered approximately 2.0 to 5.5 feet below the existing surface, based on our explorations. In general, the competent native glacial soils were shallower within the western and southern portions of the site and were deepest within the very north-central portion of the site. We should note that localized areas of deeper unsuitable soils and/or undocumented fill could be encountered at this site. This condition would require additional excavations in foundation, slab, and pavement areas to remove the unsuitable soils. Based on the results of our on-site infiltration testing and soil explorations throughout the site, it is our opinion that the onsite native granular outwash soils encountered within the site are marginally feasible for stormwater infiltration methods. This is further discussed in the Site Drainage section of this report. The surficial soils encountered on this site are considered moisture-sensitive and will disturb easily when wet. We recommend that construction take place during the drier summer months, if possible. If construction is to take place during wet weather, the soils may disturb, and additional expenses and delays may be expected due to the wet conditions. Additional expenses could include the need for placing a blanket of rock spalls to protect exposed subgrades and construction traffic areas. Some of the native on- site soils may be suitable for use as structural fill depending on the moisture content of the soil during construction. NGA should be retained to determine if the on-site soils can be used as structural fill material during construction. Erosion Control The erosion hazard for the on-site soils is interpreted to be slight for exposed soils, but actual erosion potential will be dependent on how the site is graded and how water is allowed to concentrate. Best Management Practices (BMPs) should be used to control erosion. Areas disturbed during construction should be protected from erosion. Erosion control measures may include diverting surface water away from the stripped or disturbed areas. Silt fences and/or straw bales should be erected to prevent muddy water from leaving the site. Disturbed areas should be planted as soon as practical and the vegetation should be maintained until it is established. The erosion potential of areas not stripped of vegetation should be low. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 6 NELSON GEOTECHNICAL ASSOCIATES, INC. Site Preparation and Grading After erosion control measures are implemented, site preparation should consist of stripping the topsoil, undocumented fill and loose soils from foundation, slab, pavement areas, and other structural areas, to expose medium dense or better native bearing glacial soils. The stripped soil should be removed from the site or stockpiled for later use as a landscaping fill. Based on our observations, we anticipate stripping depths of 2.0 to 5.5 feet, depending on the specific locations. In general, the competent native glacial soils were shallower within the western and southern portions of the property and deeper within the very north-central portion of the property. However, additional stripping may be required if areas of deeper undocumented fill and/or loose soil are encountered in unexplored areas of the site. After site stripping, if the exposed subgrade is deemed loose, it should be compacted to a non-yielding condition and then proof-rolled with a heavy rubber-tired piece of equipment. Areas observed to pump or weave during the proof-roll test should be reworked to structural fill specifications or over-excavated and replaced with properly compacted structural fill or rock spalls. If loose soils are encountered in the pavement areas, the loose soils should be removed and replaced with rock spalls or granular structural fill. If significant surface water flow is encountered during construction, this flow should be diverted around areas to be developed, and the exposed subgrades should be maintained in a semi-dry condition. If wet conditions are encountered, alternative site stripping and grading techniques might be necessary. These could include using large excavators equipped with wide tracks and a smooth bucket to complete site grading and covering exposed subgrade with a layer of crushed rock for protection. If wet conditions are encountered or construction is attempted in wet weather, the subgrade should not be compacted as this could cause further subgrade disturbance. In wet conditions, it may be necessary to cover the exposed subgrade with a layer of crushed rock as soon as it is exposed to protect the moisture sensitive soils from disturbance by machine or foot traffic during construction. The prepared subgrade should be protected from construction traffic and surface water should be diverted around areas of prepared subgrade. The site soils are considered to be moisture-sensitive and will disturb easily when wet. We recommend that construction take place during the drier summer months if possible. However, if construction takes place during the wet season, additional expenses and delays should be expected due to the wet conditions. Additional expenses could include the need for placing a blanket of rock spalls on exposed subgrades, construction traffic areas, and paved areas prior to placing structural fill. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 7 NELSON GEOTECHNICAL ASSOCIATES, INC. Wet weather grading will also require additional erosion control and site drainage measures. Some of the native on-site soils may be suitable for use as structural fill, depending on the moisture content of the soil at the time of construction. NGA should be retained to evaluate the suitability of all on-site and imported structural fill material during construction. Temporary and Permanent Slopes Temporary cut slope stability is a function of many factors, including the type and consistency of soils, depth of the cut, surcharge loads adjacent to the excavation, length of time a cut remains open, and the presence of surface or groundwater. It is exceedingly difficult under these variable conditions to estimate a stable, temporary, cut slope angle. Therefore, it should be the responsibility of the contractor to maintain safe slope configurations at all times as indicated in OSHA guidelines for cut slopes. The following information is provided solely for the benefit of the owner and other design consultants and should not be construed to imply that Nelson Geotechnical Associates, Inc. assumes responsibility for job site safety. Job site safety is the sole responsibility of the project contractor. For planning purposes, we recommend that temporary cuts in the upper undocumented fill/surficial soils be no steeper than 2 Horizontal to 1 Vertical (2H:1V). Temporary cuts in the competent native glacial outwash soils at depth should be no steeper than 1.5H:1V. If significant groundwater seepage or surface water flow were encountered, we would expect that flatter inclinations would be necessary. We recommend that cut slopes be protected from erosion. The slope protection measures may include covering cut slopes with plastic sheeting and diverting surface runoff away from the top of cut slopes. We do not recommend vertical slopes for cuts deeper than four feet, if worker access is necessary. We recommend that cut slope heights and inclinations conform to appropriate OSHA/WISHA regulations. Permanent cut and fill slopes should be no steeper than 2H:1V. However, flatter inclinations may be required in areas where loose soils are encountered. Permanent slopes should be vegetated, and the vegetative cover maintained until established. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 8 NELSON GEOTECHNICAL ASSOCIATES, INC. Foundations Conventional shallow spread foundations should be placed on medium dense or better native glacial outwash soils or be supported on structural fill or rock spalls extending to those soils. Native medium dense or better glacial bearing soils should be encountered approximately 2.0 to 5.5 feet below the existing ground surface based on our explorations. We typically encountered deeper areas of surficial undocumented fill soils within our explorations within the north-central portion of the site, and shallower undocumented fill soils within the western and southern portions of the site. Where undocumented fill or less dense soils are encountered at footing bearing elevation, the subgrade should be over-excavated to expose native bearing soil. The over-excavation may be filled with structural fill, or the footings may be extended down to the competent native soils. If footings are supported on structural fill, the fill zone should extend outside the edges of the footing a distance equal to half of the depth of the over-excavation below the bottom of the footing. In case of excessive undocumented fill thickness, deep foundation options may be required. NGA is available to work with the structural engineer to explore those options if is desired. Footings should extend at least 18 inches below the lowest adjacent finished ground surface for frost protection and bearing capacity considerations. Foundations should be designed in accordance with the 2018 IBC. Footing widths should be based on the anticipated loads and allowable soil bearing pressure. Water should not be allowed to accumulate in footing trenches. All loose or disturbed soil should be removed from the foundation excavation prior to placing concrete. For foundations constructed as outlined above, we recommend an allowable bearing pressure of not more than 2,000 pounds per square foot (psf) be used for the design of footings founded on the medium dense or better native soils or structural fill extending to the competent native bearing material. The foundation bearing soil should be evaluated by a representative of NGA. We should be consulted if higher bearing pressures are needed. Current IBC guidelines should be used when considering increased allowable bearing pressure for short-term transitory wind or seismic loads. Potential foundation settlement using the recommended allowable bearing pressure is estimated to be less than 1-inch total and ½-inch differential between adjacent footings or across a distance of about 20 feet, based on our experience with similar projects. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 9 NELSON GEOTECHNICAL ASSOCIATES, INC. Lateral loads may be resisted by friction on the base of the footing calculate and passive resistance against the subsurface portions of the foundation. A coefficient of friction of 0.35 may be used to the base friction and should be applied to the vertical dead load only. Passive resistance may be calculated as a triangular equivalent fluid pressure distribution. An equivalent fluid density of 200 pounds per cubic foot (pcf) should be used for passive resistance design for a level ground surface adjacent to the footing. This level surface should extend a distance equal to at least three times the footing depth. These recommended values incorporate safety factors of 1.5 and 2.0 applied to the estimated ultimate values for frictional and passive resistance, respectively. To achieve this value of passive resistance, the foundations should be poured “neat” against the native medium dense soils or compacted fill should be used as backfill against the front of the footing. We recommend that the upper one foot of soil be neglected when calculating the passive resistance. Retaining Walls Specific grading plans for this project were not available at the time this report was prepared but retaining walls may be incorporated into project plans. In general, the lateral pressure acting on retaining walls is dependent on the nature and density of the soil behind the wall, the amount of lateral wall movement which can occur as backfill is placed, wall drainage conditions, and the inclination of the backfill. For walls that are free to yield at the top at least one thousandth of the height of the wall (active condition), soil pressures will be less than if movement is limited by such factors as wall stiffness or bracing (at-rest condition). We recommend that walls supporting horizontal backfill and not subjected to hydrostatic forces, be designed using a triangular earth pressure distribution equivalent to that exerted by a fluid with a density of 35 pcf for yielding (active condition) walls, and 55 pcf for non-yielding (at-rest condition) walls. A seismic design loading of 8H should also be included in the wall design, where “H” represents the total height of the wall. These recommended lateral earth pressures are for a drained granular backfill and are based on the assumption of a horizontal ground surface behind the wall for a distance of at least the height of the wall, and do not account for surcharge loads. Additional lateral earth pressures should be considered for surcharge loads acting adjacent to walls and within a distance equal to the height of the wall. This would include the effects of surcharges such as traffic loads, floor slab loads, slopes, or other surface loads. We could consult with the structural engineer regarding additional loads on retaining walls during final design, if needed. The lateral pressures on walls may be resisted by friction between the foundation and subgrade soil, and by passive resistance acting on the below-grade portion of the foundation. Recommendations for frictional and passive resistance to lateral loads are presented in the Foundations subsection of this report. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 10 NELSON GEOTECHNICAL ASSOCIATES, INC. All wall backfill should be well compacted as outlined in the Structural Fill subsection of this report. Care should be taken to prevent the buildup of excess lateral soil pressures due to over-compaction of the wall backfill. This can be accomplished by placing wall backfill in 8-inch loose lifts and compacting the backfill with small, hand-operated compactors within a distance behind the wall equal to at least one-half the height of the wall. The thickness of the loose lifts should be reduced to accommodate the lower compactive energy of the hand-operated equipment. The recommended level of compaction should still be maintained. Permanent drainage systems should be installed for retaining walls. Recommendations for these systems are found in the Subsurface Drainage subsection of this report. We recommend that we be retained to evaluate the proposed wall drain backfill material and observe installation of the drainage systems. Structural Fill General: Fill placed beneath foundations, pavement, or other settlement-sensitive structures should be placed as structural fill. Structural fill, by definition, is placed in accordance with prescribed methods and standards, and is monitored by an experienced geotechnical professional or soils technician. Field monitoring procedures would include the performance of a representative number of in-place density tests to document the attainment of the desired degree of relative compaction. The area to receive the fill should be suitably prepared as described in the Site Preparation and Grading subsection prior to beginning fill placement. Materials: Structural fill should consist of a good quality, granular soil, free of organics and other deleterious material, and be well graded to a maximum size of about three inches. All-weather fill should contain no more than five-percent fines (soil finer than U.S. No. 200 sieve, based on that fraction passing the U.S. 3/4-inch sieve). Some of the more granular native on-site soils may be suitable for use as structural fill, but this will be highly dependent on the moisture content of these soils at the time of construction. We should be retained to evaluate all proposed structural fill material prior to placement. Fill Placement: Following subgrade preparation, placement of structural fill may proceed. All filling should be accomplished in uniform lifts up to eight inches thick. Each lift should be spread evenly and be thoroughly compacted prior to placement of subsequent lifts. All structural fill underlying building areas and pavement subgrade should be compacted to a minimum of 95 percent of its maximum dry density. Maximum dry density, in this report, refers to that density as determined by the ASTM D-1557 Compaction Test procedure. The moisture content of the soils to be compacted should be within about two percent of optimum so that a readily compactable condition exists. It may be necessary to over-excavate and remove wet soils in cases where drying to a compactable condition is not feasible. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 11 NELSON GEOTECHNICAL ASSOCIATES, INC. All compaction should be accomplished by equipment of a type and size sufficient to attain the desired degree of compaction and should be tested. Slab-on-Grade Slabs-on-grade should be supported on subgrade soils prepared as described in the Site Preparation and Grading subsection of this report. We recommend that all floor slabs be underlain by at least six inches of free-draining gravel with less than three percent by weight of the material passing Sieve #200 for use as a capillary break. A suitable vapor barrier, such as heavy plastic sheeting (6-mil, minimum), should be placed over the capillary break material. An additional 2-inch-thick moist sand layer may be used to cover the vapor barrier. This sand layer may be used to protect the vapor barrier membrane and to aid in curing the concrete. Pavements Pavement subgrade preparation and structural filling where required, should be completed as recommended in the Site Preparation and Grading and Structural Fill subsections of this report. The pavement subgrade should be proof-rolled with a heavy, rubber-tired piece of equipment, to identify soft or yielding areas that require repair. The pavement section should be underlain by a stable subgrade. We should be retained to observe the proof-rolling and recommend repairs prior to placement of the asphalt or hard surfaces. Utilities We recommend that underground utilities be bedded with a minimum six inches of pea gravel prior to backfilling the trench with on-site or imported material. Trenches within settlement sensitive areas should be compacted to 95 percent of the modified proctor as described in the Structural Fill subsection of this report. Trench backfill should be compacted to a minimum of 95 percent of the modified proctor maximum dry density. Trenches located in non-structural areas and five feet below roadway subgrade should be compacted to a minimum 90 percent of the maximum dry density. The trench backfill compaction should be tested. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 12 NELSON GEOTECHNICAL ASSOCIATES, INC. Site Drainage Infiltration: The subsurface soils within our explorations at depth generally consisted of granular glacial outwash soils to the depths explored within the western and central portion of the site and native alluvial soils within the very eastern portion of the property. In accordance with the 2022 City of Renton Surface Water Design Manual, we conducted one Small PIT within Infiltration Pit 1 within the southwestern portion of the property as shown on the attached Site Plan in Figure 2. Infiltration Pit 1 measured 5.5-feet long by 3.0-feet wide by 4.5-feet deep. At the end of the pre-soak period, the water level was maintained at 12- inches and the water flow rate into the holes was monitored with a Great Plains Industries (GPI) TM 050 water flow meter for one hour for the steady state portion of the test. The most conservative flow rate obtained from the steady state portion of the test within Infiltration Pit 1 was 0.06 gallons per minute (3.62 gallons per hour), which equates to an approximate infiltration rate of 0.32 inches per hour. The water was shut off after the steady-state period and the water level within the pit was monitored every 15 minutes for one hour. After 60 minutes, approximately 0.25 inches of water had infiltrated, resulting in an infiltration rate of 0.25 inches per hour. It is our opinion that the upper native granular outwash soils encountered at depth within the property are marginally feasible for stormwater infiltration. The subsurface soils within the property generally consisted of native outwash sand soils at depth. We have selected the most conservative measured field rate of 0.25 in/hr obtained from the falling head portion of the test in our infiltration pit to be utilized in determining the long-term design infiltration rate for the infiltration systems within the property. We referenced Equation 5-11 within Chapter 5.2.1 of the City of Renton Surface Water Design Manual that applies correction factors to the field measured infiltration rate to generate a long-term design infiltration rate. Correction factors of 0.50, 0.90, and 0.80 were utilized in this equation for Ftesting, Fgeometry, Fplugging respectively, resulting in long-term design infiltration rate of 0.09 inches per hour, to be utilized to design any on-site infiltration systems founded within the native granular outwash soils at depth within the property. We recommend that the base of the infiltration systems within the western and southern portions of the property be terminated within the native granular outwash soils encountered at approximately 2.0 to 3.0 feet below the existing ground surface. NGA should be retained to observe infiltration trench excavations. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 13 NELSON GEOTECHNICAL ASSOCIATES, INC. The stormwater manual recommends a three-foot separation between the base of an infiltration system and any underlying bedrock, impermeable horizon, or groundwater. We encountered groundwater seepage within Test Pits 3 and 4, at 9.0 and 7.5 feet below the ground surface, respectively. We recommend that the base of any proposed infiltration systems be located to maintain minimum separation from any groundwater and impermeable horizons in accordance with the City of Renton Surface Water Design Manual requirements. We also recommend that any proposed infiltration systems be placed as to not negatively impact any proposed or existing nearby structures and also meet all required setbacks from existing property lines, structures, and sensitive areas as discussed in the drainage manual. Infiltration systems should not be located within proposed fill areas within the site associated with site grading or retaining wall backfill as such condition could lead to failures of the placed fills and/or retaining structures. We recommend that the base of the on-site infiltration systems be extended through the upper undocumented fill and surficial soils and terminated within the native glacial outwash soils encountered at depth throughout the site. We should be retained during construction to evaluate the soils exposed in the infiltration systems to verify that the soils are appropriate for infiltration. We also understand that pervious pavement may be utilized in proposed driveway areas. Based on our subsurface explorations throughout the site, it is our opinion that the proposed pervious pavement is feasible. The proposed pervious pavement facility should be able to maintain greater than one-foot of separation from impermeable soils and groundwater. We recommend that the surficial soils within the proposed pervious pavement area be removed entirely to expose the competent glacial outwash soils at depth and be backfilled with free-draining crushed rock to the pavement subgrade. The pervious pavement section should be underlain by a minimum of nine inches of permeable ballast in accordance with WSDOT Specification 9.03.9(2). If groundwater protection is required for the pervious pavement section, we recommend that a six-inch-thick layer of clean sand should be placed below the crushed rock layer. We recommend the proposed pervious pavement gallery include an overflow component directed into an approved existing stormwater system if feasible. The pervious pavement section should be a minimum of six inches thick. The pavement should be swept and pressure-washed on a regular basis to ensure functionality. Surface Drainage: The finished ground surface should be graded such that stormwater is directed to an approved stormwater collection system. Water should not be allowed to stand in any areas where footings, slabs, or pavements are to be constructed. Final site grades should allow for drainage away from the residences. We suggest that the finished ground be sloped downward at a minimum gradient of three percent, for a distance of at least 10 feet away from the residences. Surface water should be collected by permanent catch basins and drain lines and be discharged into an approved discharge system. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 14 NELSON GEOTECHNICAL ASSOCIATES, INC. Subsurface Drainage: If groundwater is encountered during construction, we recommend that the contractor slope the bottom of the excavation and collect the water into ditches and small sump pits where the water can be pumped out and routed into a permanent storm drain. We recommend the use of footing drains around the structures. Footing drains should be installed at least one foot below planned finished floor elevation. The drains should consist of a minimum 4-inch-diameter, rigid, slotted or perforated, PVC pipe surrounded by free-draining material wrapped in a filter fabric. We recommend that the free-draining material consist of an 18-inch-wide zone of clean (less than three-percent fines), granular material placed along the back of walls. Pea gravel is an acceptable drain material. The free-draining material should extend up the wall to one foot below the finished surface. The top foot of backfill should consist of impermeable soil placed over plastic sheeting or building paper to minimize surface water or fines migration into the footing drain. Footing drains should discharge into tightlines leading to an approved collection and discharge point with convenient cleanouts to prolong the useful life of the drains. Roof drains should not be connected to wall or footing drains. CONSTRUCTION MONITORING We should be retained to provide construction monitoring services during the earthwork phase of the project to evaluate subgrade conditions, temporary cut conditions, fill compaction, and drainage system installation. USE OF THIS REPORT NGA has prepared this report for Gary and Kaci Aguilar and their agents, for use in the planning and design of the development on this site only. The scope of our work does not include services related to construction safety precautions and our recommendations are not intended to direct the contractors’ methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. There are possible variations in subsurface conditions between the explorations and also with time. Our report, conclusions, and interpretations should not be construed as a warranty of subsurface conditions. A contingency for unanticipated conditions should be included in the budget and schedule. We recommend that NGA be retained to provide monitoring and consultation services during construction to confirm that the conditions encountered are consistent with those indicated by the explorations, to provide recommendations for design changes should the conditions revealed differ from those anticipated, and to evaluate whether or not earthwork and foundation installation activities comply with contract plans and specifications. We should be contacted a minimum of one week prior to construction activities and could attend pre-construction meetings if requested. Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 15 NELSON GEOTECHNICAL ASSOCIATES, INC. Within the limitations of scope, schedule, and budget, our services have been performed in accordance with generally accepted geotechnical engineering practices in effect in this area at the time this report was prepared. No other warranty, expressed or implied, is made. Our observations, findings, and opinions are a means to identify and reduce the inherent risks to the owner. o-o-o Geotechnical Engineering Evaluation NGA File No. 1388322 Aguilar North 35th Street Residence Development September 20, 2022 Renton, Washington Page 16 NELSON GEOTECHNICAL ASSOCIATES, INC. It has been a pleasure to provide service to you on this project. If you have any questions or require further information, please call. Sincerely, NELSON GEOTECHNICAL ASSOCIATES, INC. Lee S. Bellah, LG Senior Geologist Khaled M. Shawish, PE Principal LSB:KMS:dy Five Figures Attached 9.20.2022 Not to Scale VICINITY MAP Aguilar Residence Development Vicinity Map Project Site 1 No.Project Number Date By CKRevision Woodinville Office 17311-135th Ave. NE, A-500 Woodinville, WA 98072 (425) 486-1669 / Fax: 481-2510 Wenatchee Office 105 Palouse St. Wenatchee, WA 98801 (509) 665-7696 / Fax: 665-7692www.nelsongeotech.com C:\Users\DannyNelson\Nelson Geotechnical Associates, Inc\Nelson Geotechnical Associates, Inc - Company\2022 NGA Project\13883-22 Aguilar North 35th Street Res Dev Renton\Drafting\VM.dwg8/28/22 DPN LSBOriginal Figure 1 1388322 Renton, WA Reference: Site plan based on a plan dated June 10, 2022 titled "Boundary Topographic Survey for Gary Aguilar," prepared by Encompass.1No.Project NumberDateByCKRevisionWoodinville Office17311-135th Ave. NE, A-500Woodinville, WA 98072(425) 486-1669 / Fax: 481-2510Wenatchee Office105 Palouse St.Wenatchee, WA 98801(509) 665-7696 / Fax: 665-7692www.nelsongeotech.comC:\Users\DannyNelson\Nelson Geotechnical Associates, Inc\Nelson Geotechnical Associates, Inc - Company\2022 NGA Project\13883-22 Aguilar North 35th Street Res Dev Renton\Drafting\SP.dwgFigure 213883228/28/22DPNLSBOriginal Aguilar ResidenceDevelopmentSite PlanSite Plan LEGEND INF-1 Number and approximate location of infiltration test pit Property line TP-1 Number and approximate location of test pit N 35th St Scale: 1 inch = 30 feet 0 30 60 Existing House Existing GarageTP-4 TP-3 INF-1 TP-1 TP-2 GW GP GM GC SW SP SM SC ML CL OL MH CH OH PT PEAT ORGANIC CLAY, ORGANIC SILT CLAY OF HIGH PLASTICITY, FAT CLAY SILT OF HIGH PLASTICITY, ELASTIC SILT SILTY SAND SILT ORGANIC SILT, ORGANIC CLAY CLAY CLAYEY SAND POORLY GRADED SAND WELL-GRADED SAND, FINE TO COARSE SAND CLAYEY GRAVEL SILTY GRAVEL POORLY-GRADED GRAVEL WELL-GRADED, FINE TO COARSE GRAVELCLEAN GRAVEL GRAVEL WITH FINES CLEAN SAND SAND WITH FINES INORGANIC ORGANIC INORGANIC ORGANIC HIGHLY ORGANIC SOILS GRAVEL SAND SILT AND CLAY SILT AND CLAY MORE THAN 50 % OF COARSE FRACTION RETAINED ON NO. 4 SIEVE PASSES NO. 4 SIEVE LIQUID LIMIT LESS THAN 50 % 50 % OR MORE LIQUID LIMIT MORE THAN 50 % OF COARSE FRACTION COARSE - GRAINED SOILS FINE - GRAINED SOILS MORE THAN 50 % RETAINED ON NO. 200 SIEVE PASSES NO. 200 SIEVE MORE THAN 50 % MAJOR DIVISIONS GROUP SYMBOL GROUP NAME UNIFIED SOIL CLASSIFICATION SYSTEM NOTES: 1) Field classification is based on visual examination of soil in general accordance with ASTM D 2488-93. 2) Soil classification using laboratory tests is based on ASTM D 2488-93. 3) Descriptions of soil density or consistency are based on interpretation of blowcount data, visual appearance of soils, and/or test data. SOIL MOISTURE MODIFIERS: Dry - Absence of moisture, dusty, dry to the touch Moist - Damp, but no visible water. Wet - Visible free water or saturated, usually soil is obtained from below water table 1 No.Project Number Date By CKRevision Woodinville Office 17311-135th Ave. NE, A-500 Woodinville, WA 98072 (425) 486-1669 / Fax: 481-2510 Wenatchee Office 105 Palouse St. Wenatchee, WA 98801 (509) 665-7696 / Fax: 665-7692www.nelsongeotech.com C:\Users\DannyNelson\Nelson Geotechnical Associates, Inc\Nelson Geotechnical Associates, Inc - Company\2022 NGA Project\13883-22 Aguilar North 35th Street Res Dev Renton\Drafting\SC.dwgFigure 3 1388322 8/28/22 DPN LSBOriginal Aguilar Residence Development Soil Classification Chart LOG OF EXPLORATION DEPTH (FEET) USCS SOIL DESCRIPTION DPN:LSB NELSON GEOTECHNICAL ASSOCIATES, INC. FILE NO 1388322 FIGURE 4 INFILTRATION TEST PIT ONE 0.0 – 3.0 GRASS UNDERLAIN BY DARK BROWN, SILTY FINE TO MEDIUM SAND WITH GRAVEL, ROOTS, AND ORGANICS (LOOSE, DRY TO MOIST) (FILL) 3.0 – 6.0 SP-SM LIGHT YELLOWISH-BROWN, FINE TO MEDIUM SAND WITH SILT, IRON-OXIDE STAINING, AND SILTY SAND LENSES (MEDIUM DENSE TO DENSE, MOIST) SAMPLES WERE NOT COLLECTED GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 6.0 FEET ON 08/25/2022 TEST PIT ONE 0.0 – 2.5 GRASS AND TOPSOIL 2.5 – 5.5 DARK BROWN, SILTY FINE TO MEDIUM SAND WITH ROOTS, GRAVEL, AND TRACE COBBLES (LOOSE TO MEDIUM DENSE, MOIST) (FILL) 5.5 – 9.0 SM GRAY, SILTY FINE SAND WITH GRAVEL, IRON-OXIDE STAINING, AND TRACE COBBLES (MEDIUM DENSE TO DENSE, MOIST) 9.0 – 10.0 SP-SM GRAY, FINE TO MEDIUM SAND WITH SILT AND GRAVEL (MEDIUM DENSE TO DENSE, MOIST) SAMPLES WERE COLLECTED AT 7.5 AND 9.0 FEET GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 10.0 FEET ON 08/25/2022 TEST PIT TWO 0.0 – 1.0 GRASS AND TOPSOIL 1.0 – 2.0 LIGHT GRAY, SILTY FINE TO MEDIUM SAND WITH ROOTS AND TRACE GRAVEL (LOOSE TO MEDIUM DENSE, MOIST) (FILL) 2.0 – 7.5 SM GRAY, SILTY FINE SAND WITH GRAVEL, IRON-OXIDE STAINING, AND TRACE COBBLES (MEDIUM DENSE TO DENSE, MOIST) 7.5 – 10.0 SP-SM GRAY, FINE TO MEDIUM SAND WITH SILT, GRAVEL, AND COBBLES (MEDIUM DENSE TO DENSE, MOIST) SAMPLES WERE COLLECTED AT 4.0, 5.0, AND 7.5 FEET GROUNDWATER SEEPAGE WAS NOT ENCOUNTERED TEST PIT CAVING WAS NOT ENCOUNTERED TEST PIT WAS COMPLETED AT 10.0 FEET ON 08/25/2022 TEST PIT THREE 0.0 – 2.5 GRASS AND TOPSOIL 2.5 – 6.0 SP-SM LIGHT BROWN, FINE TO MEDIUM SAND WITH SILT AND GRAVEL (MEDIUM DENSE TO DENSE, MOIST) 6.0 – 7.5 SM GRAY, SILTY FINE SAND WITH TRACE GRAVEL (MEDIUM DENSE TO DENSE, MOIST) 7.5 – 10.0 SP-SM LIGHT YELLOWISH-BROWN, FINE TO MEDIUM SAND WITH SILT AND GRAVEL (MEDIUM DENSE TO DENSE, MOIST TO WET) SAMPLES WERE COLLECTED AT 5.0 AND 9.0 FEET GROUNDWATER SEEPAGE WAS ENCOUNTERED AT 9.0 FEET MINOR TEST PIT CAVING WAS ENCOUNTERED FROM 9.0 TO 10.0 FEET TEST PIT WAS COMPLETED AT 10.0 FEET ON 08/25/2022 LOG OF EXPLORATION DEPTH (FEET) USCS SOIL DESCRIPTION DPN:LSB NELSON GEOTECHNICAL ASSOCIATES, INC. FILE NO 1388322 FIGURE 5 TEST PIT FOUR 0.0 – 2.2 GRASS UNDERLAIN BY LIGHT TO DARK BROWN, SILTY FINE TO MEDIUM SAND WITH GRAVEL, ROOTS, AND PLASTIC DEBRIS (LOOSE TO MEDIUM DENSE, MOIST) (FILL) 2.2 – 4.5 SP-SM LIGHT BROWN, FINE TO MEDIUM SAND WITH SILT AND IRON-OXIDE WEATHERING (MEDIUM DENSE TO DENSE, MOIST) 4.5 – 8.0 SP-SM GRAY, FINE TO MEDIUM SAND WITH SILT, GRAVEL, AND SILTY LENSES (MEDIUM DENSE TO DENSE, MOIST TO WET) SAMPLES WERE COLLECTED AT 4.5 AND 7.5 FEET GROUNDWATER SEEPAGE WAS ENCOUNTERED AT 7.5 FEET MINOR TEST PIT CAVING WAS ENCOUNTERED FROM 7.5 TO 8.0 FEET TEST PIT WAS COMPLETED AT 8.0 FEET ON 08/25/2022 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 35 of 39 APPENDIX C – DECLARATION OF COVENANT AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 36 of 39 APPENDIX D – OPERATIONS AND MAINTENANCE MANUAL APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2022 City of Renton Surface Water Design Manual 6/22/2022 A-41 NO. 30 – PERMEABLE PAVEMENT BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Surface cleaning/ vegetation control Media surface vacuumed or pressure washed annually, vegetation controlled to design maximum. Weed growth suggesting sediment accumulation. No dirt, sediment, or debris clogging porous media, or vegetation limiting infiltration. Porous Concrete, Porous Asphaltic Concrete, and Permeable Pavers Trash and debris Trash and debris on the pavement interfering with infiltration; leaf drop in fall season. No trash or debris interfering with infiltration. Sediment accumulation Sediment accumulation on the pavement interfering with infiltration; runoff from adjacent areas depositing sediment/debris on pavement. Pavement infiltrates as designed; adjacent areas stabilized. Insufficient infiltration rate Pavement does not infiltrate at a rate of 10 inches per hour. Pavement infiltrates at a rate greater than 10 inches per hour. Excessive ponding Standing water for a long period of time on the surface of the pavement. Standing water infiltrates at the desired rate. Broken or cracked pavement Pavement is broken or cracked. No broken pavement or cracks on the surface of the pavement. Settlement Uneven pavement surface indicating settlement of the subsurface layer. Pavement surface is uniformly level. Moss growth Moss growing on pavement interfering with infiltration. No moss interferes with infiltration. Inflow restricted Inflow to the pavement is diverted, restricted, or depositing sediment and debris on the pavement. Inflow to pavement is unobstructed and not bringing sediment or debris to the pavement. Underdrain not freely flowing Underdrain is not flowing when pavement has been infiltrating water. Underdrain flows freely when water is present. Overflow not controlling excess water Overflow not controlling excess water to desired location; native soil is exposed or other signs of erosion damage are present. Overflow permits excess water to leave the site at the desired location; Overflow is stabilized and appropriately armored. Permeable Pavers Broken or missing pavers Broken or missing paving blocks on surface of pavement. No missing or broken paving blocks interfering with infiltration. Uneven surface Uneven surface due to settlement or scour of fill in the interstices of the paving blocks. Pavement surface is uniformly level. Compaction Poor infiltration due to soil compaction between paving blocks. No soil compaction in the interstices of the paver blocks limiting infiltration. Poor vegetation growth (if applicable) Grass in the interstices of the paving blocks is dead. Healthy grass is growing in the interstices of the paver blocks. MAINTENANCE INSTRUCTIONS FOR SOIL AMENDMENT Your property contains an on-site BMP (best management practice) called “soil amendment,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the pervious surfaces on your property. Soil amendment is a method of regaining greater stormwater functions in the post development landscape by increasing treatment of pollutants and sediments, and minimizing the need for some landscaping chemicals. To be successful, the soil condition must be able to soak water into the ground for a reasonable number of years. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual. MAINTENANCE RESTRICTIONS The size, placement, and composition of these devices as depicted by the site plan and design details must be maintained and may not be changed without written approval from the City of Renton or through a future development permit from the City of Renton. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES To be successful, the soil must be able to soak water into the ground for a reasonable number of years.  Return leaf fall and shredded woody materials from the landscape to the site when possible in order to replenish soil nutrients and structure.  On turf areas, “grasscycle” (mulch-mow or leave the clippings) to build turf health.  Maintain 2 to 3 inches of mulch over bare areas in landscape beds.  Re-seed bare turf areas until the vegetation fully covers the ground surface.  Avoid using pesticides (bug and weed killers) which damage the soil.  Where fertilization is needed (mainly turf and annual flower beds), a moderate fertilization program should be used which relies on compost, natural fertilizers, or slow-release synthetic balanced fertilizers. RECORDING REQUIREMENT These on-site BMP maintenance and operation instructions must be recorded as an attachment to the required declaration of covenant and grant of easement per Requirement 3 of Section C.1.3.4 of the City of Renton Surface Water Design Manual. The intent of these instructions is to explain to future property owners, the purpose of the BMP and how it must be maintained and operated. These instructions are intended to be a minimum; the City of Renton may require additional instructions based on site-specific conditions. See the City of Renton’s Surface Water Design Manual website for additional information and updates. AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 37 of 39 APPENDIX E – WWHM REPORT WWHM2012 PROJECT REPORT Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 2 General Model Information Project Name:Aguilar SFR Renton Site Name:Aguilar SFR Site Address:1011 N 35th ST City:Renton Report Date:6/14/2023 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2021/08/18 Version:4.2.18 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.21 Pervious Total 0.21 Impervious Land Use acre ROADS FLAT 0.07 Impervious Total 0.07 Basin Total 0.28 Element Flows To: Surface Interflow Groundwater Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 4 Mitigated Land Use Basin 1 Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.12 Pervious Total 0.12 Impervious Land Use acre ROADS FLAT 0.14 Impervious Total 0.14 Basin Total 0.26 Element Flows To: Surface Interflow Groundwater Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 5 Routing Elements Predeveloped Routing Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 6 Mitigated Routing Permeable Pavement 1 Pavement Area:0.0249 acre.Pavement Length: 108.50 ft. Pavement Width: 10.00 ft. Pavement slope 1:0.01 To 1 Pavement thickness: 0.25 Pour Space of Pavement: 0.33 Material thickness of second layer: 0.5 Pour Space of material for second layer: 0.33 Material thickness of third layer: 0.5 Pour Space of material for third layer: 0.33 Infiltration On Infiltration rate:0.09 Infiltration safety factor:1 Wetted surface area On Total Volume Infiltrated (ac-ft.):3.639 Total Volume Through Riser (ac-ft.):0 Total Volume Through Facility (ac-ft.):3.639 Percent Infiltrated:100 Total Precip Applied to Facility:0 Total Evap From Facility:0.271 Element Flows To: Outlet 1 Outlet 2 Permeable Pavement Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.024 0.000 0.000 0.000 0.0139 0.024 0.000 0.000 0.002 0.0278 0.024 0.000 0.000 0.002 0.0417 0.024 0.000 0.000 0.002 0.0556 0.024 0.000 0.000 0.002 0.0694 0.024 0.000 0.000 0.002 0.0833 0.024 0.000 0.000 0.002 0.0972 0.024 0.000 0.000 0.002 0.1111 0.024 0.000 0.000 0.002 0.1250 0.024 0.001 0.000 0.002 0.1389 0.024 0.001 0.000 0.002 0.1528 0.024 0.001 0.000 0.002 0.1667 0.024 0.001 0.000 0.002 0.1806 0.024 0.001 0.000 0.002 0.1944 0.024 0.001 0.000 0.002 0.2083 0.024 0.001 0.000 0.002 0.2222 0.024 0.001 0.000 0.002 0.2361 0.024 0.001 0.000 0.002 0.2500 0.024 0.002 0.000 0.002 0.2639 0.024 0.002 0.000 0.002 0.2778 0.024 0.002 0.000 0.002 0.2917 0.024 0.002 0.000 0.002 0.3056 0.024 0.002 0.000 0.002 0.3194 0.024 0.002 0.000 0.002 0.3333 0.024 0.002 0.000 0.002 0.3472 0.024 0.002 0.000 0.002 0.3611 0.024 0.003 0.000 0.002 0.3750 0.024 0.003 0.000 0.002 Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 7 0.3889 0.024 0.003 0.000 0.002 0.4028 0.024 0.003 0.000 0.002 0.4167 0.024 0.003 0.000 0.002 0.4306 0.024 0.003 0.000 0.002 0.4444 0.024 0.003 0.000 0.002 0.4583 0.024 0.003 0.000 0.002 0.4722 0.024 0.003 0.000 0.002 0.4861 0.024 0.004 0.000 0.002 0.5000 0.024 0.004 0.000 0.002 0.5139 0.024 0.004 0.000 0.002 0.5278 0.024 0.004 0.000 0.002 0.5417 0.024 0.004 0.000 0.002 0.5556 0.024 0.004 0.000 0.002 0.5694 0.024 0.004 0.000 0.002 0.5833 0.024 0.004 0.000 0.002 0.5972 0.024 0.004 0.000 0.002 0.6111 0.024 0.005 0.000 0.002 0.6250 0.024 0.005 0.000 0.002 0.6389 0.024 0.005 0.000 0.002 0.6528 0.024 0.005 0.000 0.002 0.6667 0.024 0.005 0.000 0.002 0.6806 0.024 0.005 0.000 0.002 0.6944 0.024 0.005 0.000 0.002 0.7083 0.024 0.005 0.000 0.002 0.7222 0.024 0.005 0.000 0.002 0.7361 0.024 0.006 0.000 0.002 0.7500 0.024 0.006 0.000 0.002 0.7639 0.024 0.006 0.000 0.002 0.7778 0.024 0.006 0.000 0.002 0.7917 0.024 0.006 0.000 0.002 0.8056 0.024 0.006 0.000 0.002 0.8194 0.024 0.006 0.000 0.002 0.8333 0.024 0.006 0.000 0.002 0.8472 0.024 0.007 0.000 0.002 0.8611 0.024 0.007 0.000 0.002 0.8750 0.024 0.007 0.000 0.002 0.8889 0.024 0.007 0.000 0.002 0.9028 0.024 0.007 0.000 0.002 0.9167 0.024 0.007 0.000 0.002 0.9306 0.024 0.007 0.000 0.002 0.9444 0.024 0.007 0.000 0.002 0.9583 0.024 0.007 0.000 0.002 0.9722 0.024 0.008 0.000 0.002 0.9861 0.024 0.008 0.000 0.002 1.0000 0.024 0.008 0.000 0.002 1.0139 0.024 0.008 0.000 0.002 1.0278 0.024 0.008 0.000 0.002 1.0417 0.024 0.008 0.000 0.002 1.0556 0.024 0.008 0.000 0.002 1.0694 0.024 0.008 0.000 0.002 1.0833 0.024 0.008 0.000 0.002 1.0972 0.024 0.009 0.000 0.002 1.1111 0.024 0.009 0.000 0.002 1.1250 0.024 0.009 0.000 0.002 1.1389 0.024 0.009 0.000 0.002 1.1528 0.024 0.009 0.000 0.002 1.1667 0.024 0.009 0.000 0.002 1.1806 0.024 0.009 0.000 0.002 Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 8 1.1944 0.024 0.009 0.000 0.002 1.2083 0.024 0.009 0.000 0.002 1.2222 0.024 0.010 0.000 0.002 1.2361 0.024 0.010 0.000 0.002 1.2500 0.024 0.010 0.000 0.002 Aguilar SFR Renton 6/14/2023 10:21:05 AM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.21 Total Impervious Area:0.07 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.12 Total Impervious Area:0.164908 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.041367 5 year 0.060189 10 year 0.074441 25 year 0.094579 50 year 0.111189 100 year 0.129234 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.061332 5 year 0.080995 10 year 0.09482 25 year 0.113242 50 year 0.127678 100 year 0.142741 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.066 0.087 1950 0.067 0.080 1951 0.040 0.054 1952 0.024 0.040 1953 0.023 0.043 1954 0.033 0.050 1955 0.034 0.055 1956 0.035 0.054 1957 0.048 0.066 1958 0.030 0.049 Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 10 1959 0.023 0.045 1960 0.043 0.056 1961 0.038 0.055 1962 0.025 0.043 1963 0.037 0.054 1964 0.032 0.049 1965 0.051 0.070 1966 0.026 0.042 1967 0.068 0.080 1968 0.055 0.085 1969 0.046 0.063 1970 0.038 0.057 1971 0.046 0.068 1972 0.064 0.080 1973 0.023 0.037 1974 0.046 0.065 1975 0.049 0.067 1976 0.035 0.050 1977 0.032 0.048 1978 0.039 0.059 1979 0.042 0.078 1980 0.076 0.092 1981 0.040 0.063 1982 0.075 0.096 1983 0.040 0.068 1984 0.030 0.046 1985 0.041 0.063 1986 0.040 0.054 1987 0.044 0.078 1988 0.023 0.045 1989 0.028 0.056 1990 0.127 0.140 1991 0.087 0.104 1992 0.030 0.046 1993 0.022 0.037 1994 0.019 0.038 1995 0.034 0.055 1996 0.057 0.067 1997 0.046 0.063 1998 0.036 0.056 1999 0.095 0.130 2000 0.042 0.062 2001 0.033 0.060 2002 0.065 0.086 2003 0.051 0.067 2004 0.086 0.120 2005 0.040 0.055 2006 0.038 0.050 2007 0.115 0.126 2008 0.086 0.102 2009 0.050 0.069 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1265 0.1402 2 0.1155 0.1299 3 0.0948 0.1260 Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 11 4 0.0873 0.1197 5 0.0855 0.1042 6 0.0855 0.1022 7 0.0761 0.0961 8 0.0746 0.0922 9 0.0682 0.0865 10 0.0674 0.0857 11 0.0655 0.0845 12 0.0654 0.0804 13 0.0642 0.0802 14 0.0570 0.0795 15 0.0553 0.0783 16 0.0511 0.0782 17 0.0509 0.0696 18 0.0504 0.0693 19 0.0493 0.0683 20 0.0475 0.0683 21 0.0461 0.0674 22 0.0459 0.0671 23 0.0458 0.0666 24 0.0458 0.0664 25 0.0439 0.0648 26 0.0426 0.0632 27 0.0419 0.0631 28 0.0417 0.0628 29 0.0409 0.0627 30 0.0400 0.0615 31 0.0400 0.0603 32 0.0399 0.0592 33 0.0396 0.0572 34 0.0396 0.0565 35 0.0388 0.0560 36 0.0381 0.0557 37 0.0381 0.0553 38 0.0379 0.0552 39 0.0370 0.0549 40 0.0357 0.0547 41 0.0352 0.0543 42 0.0346 0.0542 43 0.0344 0.0537 44 0.0342 0.0536 45 0.0330 0.0504 46 0.0330 0.0500 47 0.0325 0.0499 48 0.0322 0.0493 49 0.0301 0.0486 50 0.0300 0.0475 51 0.0296 0.0460 52 0.0283 0.0456 53 0.0264 0.0453 54 0.0249 0.0452 55 0.0244 0.0434 56 0.0234 0.0430 57 0.0229 0.0421 58 0.0228 0.0397 59 0.0226 0.0377 60 0.0219 0.0372 61 0.0189 0.0371 Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 12 Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 13 Duration Flows Flow(cfs)Predev Mit Percentage Pass/Fail 0.0207 1424 5565 390 Fail 0.0216 1242 4900 394 Fail 0.0225 1084 4312 397 Fail 0.0234 934 3788 405 Fail 0.0243 827 3373 407 Fail 0.0253 718 3037 422 Fail 0.0262 623 2680 430 Fail 0.0271 559 2413 431 Fail 0.0280 510 2150 421 Fail 0.0289 473 1939 409 Fail 0.0298 418 1733 414 Fail 0.0307 383 1583 413 Fail 0.0317 346 1423 411 Fail 0.0326 317 1279 403 Fail 0.0335 290 1165 401 Fail 0.0344 267 1059 396 Fail 0.0353 246 955 388 Fail 0.0362 222 861 387 Fail 0.0371 207 784 378 Fail 0.0381 194 730 376 Fail 0.0390 177 666 376 Fail 0.0399 162 615 379 Fail 0.0408 150 564 376 Fail 0.0417 139 524 376 Fail 0.0426 128 486 379 Fail 0.0435 120 452 376 Fail 0.0445 115 420 365 Fail 0.0454 109 387 355 Fail 0.0463 99 361 364 Fail 0.0472 97 340 350 Fail 0.0481 94 320 340 Fail 0.0490 90 302 335 Fail 0.0499 84 283 336 Fail 0.0509 76 262 344 Fail 0.0518 70 244 348 Fail 0.0527 67 226 337 Fail 0.0536 63 213 338 Fail 0.0545 61 200 327 Fail 0.0554 57 183 321 Fail 0.0563 54 171 316 Fail 0.0573 52 158 303 Fail 0.0582 48 151 314 Fail 0.0591 47 142 302 Fail 0.0600 45 132 293 Fail 0.0609 40 127 317 Fail 0.0618 39 119 305 Fail 0.0627 39 111 284 Fail 0.0637 38 106 278 Fail 0.0646 37 102 275 Fail 0.0655 35 101 288 Fail 0.0664 33 96 290 Fail 0.0673 31 90 290 Fail 0.0682 29 82 282 Fail 0.0691 27 77 285 Fail Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 14 0.0701 25 72 288 Fail 0.0710 24 71 295 Fail 0.0719 24 70 291 Fail 0.0728 22 66 300 Fail 0.0737 20 63 315 Fail 0.0746 19 61 321 Fail 0.0755 18 57 316 Fail 0.0764 16 57 356 Fail 0.0774 15 55 366 Fail 0.0783 14 51 364 Fail 0.0792 14 46 328 Fail 0.0801 14 43 307 Fail 0.0810 14 40 285 Fail 0.0819 13 37 284 Fail 0.0828 12 34 283 Fail 0.0838 10 33 330 Fail 0.0847 10 31 310 Fail 0.0856 8 30 375 Fail 0.0865 8 29 362 Fail 0.0874 7 27 385 Fail 0.0883 7 25 357 Fail 0.0892 5 24 480 Fail 0.0902 4 23 575 Fail 0.0911 4 22 550 Fail 0.0920 4 22 550 Fail 0.0929 3 20 666 Fail 0.0938 3 19 633 Fail 0.0947 3 17 566 Fail 0.0956 2 17 850 Fail 0.0966 2 15 750 Fail 0.0975 2 15 750 Fail 0.0984 2 14 700 Fail 0.0993 2 14 700 Fail 0.1002 2 12 600 Fail 0.1011 2 11 550 Fail 0.1020 2 11 550 Fail 0.1030 2 10 500 Fail 0.1039 2 10 500 Fail 0.1048 2 8 400 Fail 0.1057 2 7 350 Fail 0.1066 2 7 350 Fail 0.1075 2 7 350 Fail 0.1084 2 7 350 Fail 0.1094 2 7 350 Fail 0.1103 2 7 350 Fail 0.1112 2 7 350 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. Aguilar SFR Renton 6/14/2023 10:21:32 AM 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. Aguilar SFR Renton 6/14/2023 10:21:32 AM Page 16 LID Report Aguilar SFR Renton 6/14/2023 10:21:50 AM Page 17 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Aguilar SFR Renton 6/14/2023 10:21:50 AM Page 18 Appendix Predeveloped Schematic Aguilar SFR Renton 6/14/2023 10:21:50 AM Page 19 Mitigated Schematic Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 20 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Aguilar SFR Renton.wdm MESSU 25 PreAguilar SFR Renton.MES 27 PreAguilar SFR Renton.L61 28 PreAguilar SFR Renton.L62 30 POCAguilar SFR Renton1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 21 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 1 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 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 END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 22 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 0.21 COPY 501 12 PERLND 16 0.21 COPY 501 13 IMPLND 1 0.07 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 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 Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 23 END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 24 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 Aguilar SFR Renton.wdm MESSU 25 MitAguilar SFR Renton.MES 27 MitAguilar SFR Renton.L61 28 MitAguilar SFR Renton.L62 30 POCAguilar SFR Renton1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 1 IMPLND 16 RCHRES 1 COPY 1 COPY 501 COPY 601 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Permeable Pavement 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 601 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 25 PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 1 ROADS/FLAT 1 1 1 27 0 16 Porous Pavement 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 16 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 1 0 0 4 0 0 0 1 9 16 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 16 0 0 0 0 0 END IWAT-PARM1 IWAT-PARM2 Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 26 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 1 400 0.01 0.1 0.1 16 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 1 0 0 16 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 1 0 0 16 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** IMPLND 16 0.0249 RCHRES 1 5 Basin 1*** PERLND 16 0.12 COPY 501 12 PERLND 16 0.12 COPY 601 12 PERLND 16 0.12 COPY 501 13 PERLND 16 0.12 COPY 601 13 IMPLND 1 0.14 COPY 501 15 IMPLND 1 0.14 COPY 601 15 ******Routing****** RCHRES 1 1 COPY 501 17 END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** 1 Permeable Paveme-007 2 1 1 1 28 0 1 END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** 1 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* 1 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 27 HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** 1 0 1 0 0 4 5 0 0 0 0 0 0 0 0 2 2 2 2 2 END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** 1 1 0.02 0.0 0.0 0.5 0.0 END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> 1 0 4.0 5.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES FTABLE 1 91 5 Depth Area Volume Outflow1 Outflow2 Velocity Travel Time*** (ft) (acres) (acre-ft) (cfs) (cfs) (ft/sec) (Minutes)*** 0.000000 0.024908 0.000000 0.000000 0.000000 0.013889 0.024908 0.000114 0.000000 0.002260 0.027778 0.024908 0.000228 0.000000 0.002260 0.041667 0.024908 0.000342 0.000000 0.002260 0.055556 0.024908 0.000457 0.000000 0.002260 0.069444 0.024908 0.000571 0.000000 0.002260 0.083333 0.024908 0.000685 0.000000 0.002260 0.097222 0.024908 0.000799 0.000000 0.002260 0.111111 0.024908 0.000913 0.000000 0.002260 0.125000 0.024908 0.001027 0.000000 0.002260 0.138889 0.024908 0.001142 0.000000 0.002260 0.152778 0.024908 0.001256 0.000000 0.002260 0.166667 0.024908 0.001370 0.000000 0.002260 0.180556 0.024908 0.001484 0.000000 0.002260 0.194444 0.024908 0.001598 0.000000 0.002260 0.208333 0.024908 0.001712 0.000000 0.002261 0.222222 0.024908 0.001827 0.000000 0.002261 0.236111 0.024908 0.001941 0.000000 0.002261 0.250000 0.024908 0.002055 0.000000 0.002261 0.263889 0.024908 0.002169 0.000000 0.002261 0.277778 0.024908 0.002283 0.000000 0.002261 0.291667 0.024908 0.002397 0.000000 0.002261 0.305556 0.024908 0.002512 0.000000 0.002261 0.319444 0.024908 0.002626 0.000000 0.002261 0.333333 0.024908 0.002740 0.000000 0.002261 0.347222 0.024908 0.002854 0.000000 0.002261 0.361111 0.024908 0.002968 0.000000 0.002261 0.375000 0.024908 0.003082 0.000000 0.002261 0.388889 0.024908 0.003197 0.000000 0.002261 0.402778 0.024908 0.003311 0.000000 0.002261 0.416667 0.024908 0.003425 0.000000 0.002261 0.430556 0.024908 0.003539 0.000000 0.002261 0.444444 0.024908 0.003653 0.000000 0.002261 0.458333 0.024908 0.003767 0.000000 0.002261 0.472222 0.024908 0.003882 0.000000 0.002261 0.486111 0.024908 0.003996 0.000000 0.002261 0.500000 0.024908 0.004110 0.000000 0.002261 0.513889 0.024908 0.004224 0.000000 0.002261 0.527778 0.024908 0.004338 0.000000 0.002261 0.541667 0.024908 0.004452 0.000000 0.002261 0.555556 0.024908 0.004566 0.000000 0.002261 Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 28 0.569444 0.024908 0.004681 0.000000 0.002261 0.583333 0.024908 0.004795 0.000000 0.002261 0.597222 0.024908 0.004909 0.000000 0.002261 0.611111 0.024908 0.005023 0.000000 0.002261 0.625000 0.024908 0.005137 0.000000 0.002261 0.638889 0.024908 0.005251 0.000000 0.002261 0.652778 0.024908 0.005366 0.000000 0.002261 0.666667 0.024908 0.005480 0.000000 0.002261 0.680556 0.024908 0.005594 0.000000 0.002261 0.694444 0.024908 0.005708 0.000000 0.002261 0.708333 0.024908 0.005822 0.000000 0.002261 0.722222 0.024908 0.005936 0.000000 0.002261 0.736111 0.024908 0.006051 0.000000 0.002261 0.750000 0.024908 0.006165 0.000000 0.002261 0.763889 0.024908 0.006279 0.000000 0.002261 0.777778 0.024908 0.006393 0.000000 0.002261 0.791667 0.024908 0.006507 0.000000 0.002261 0.805556 0.024908 0.006621 0.000000 0.002261 0.819444 0.024908 0.006736 0.000000 0.002261 0.833333 0.024908 0.006850 0.000000 0.002261 0.847222 0.024908 0.006964 0.000000 0.002261 0.861111 0.024908 0.007078 0.000000 0.002261 0.875000 0.024908 0.007192 0.000000 0.002261 0.888889 0.024908 0.007306 0.000000 0.002261 0.902778 0.024908 0.007421 0.000000 0.002261 0.916667 0.024908 0.007535 0.000000 0.002261 0.930556 0.024908 0.007649 0.000000 0.002261 0.944444 0.024908 0.007763 0.000000 0.002261 0.958333 0.024908 0.007877 0.000000 0.002261 0.972222 0.024908 0.007991 0.000000 0.002261 0.986111 0.024908 0.008106 0.000000 0.002261 1.000000 0.024908 0.008220 0.000000 0.002261 1.013889 0.024908 0.008334 0.000000 0.002261 1.027778 0.024908 0.008448 0.000000 0.002261 1.041667 0.024908 0.008562 0.000000 0.002261 1.055556 0.024908 0.008676 0.000000 0.002261 1.069444 0.024908 0.008791 0.000000 0.002261 1.083333 0.024908 0.008905 0.000000 0.002261 1.097222 0.024908 0.009019 0.000000 0.002261 1.111111 0.024908 0.009133 0.000000 0.002261 1.125000 0.024908 0.009247 0.000000 0.002261 1.138889 0.024908 0.009361 0.000000 0.002261 1.152778 0.024908 0.009475 0.000000 0.002261 1.166667 0.024908 0.009590 0.000000 0.002261 1.180556 0.024908 0.009704 0.000000 0.002261 1.194444 0.024908 0.009818 0.000000 0.002261 1.208333 0.024908 0.009932 0.000000 0.002261 1.222222 0.024908 0.010046 0.000000 0.002261 1.236111 0.024908 0.010160 0.000000 0.002261 1.250000 0.024908 0.010275 0.000000 0.002261 END FTABLE 1 END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 RCHRES 1 EXTNL POTEV END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL COPY 601 OUTPUT MEAN 1 1 48.4 WDM 901 FLOW ENGL REPL Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 29 END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 5 IMPLND IWATER SURO 0.083333 RCHRES INFLOW IVOL END MASS-LINK 5 MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 MASS-LINK 17 RCHRES OFLOW OVOL 1 COPY INPUT MEAN END MASS-LINK 17 END MASS-LINK END RUN Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 30 Predeveloped HSPF Message File Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 31 Mitigated HSPF Message File Aguilar SFR Renton 6/14/2023 10:21:51 AM Page 32 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2023; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 38 of 39 APPENDIX F – DOWNSTREAM INLET CALCULATIONS Project Description 22073 SSA.SPF Project Options CFS Elevation Santa Barbara UH SCS TR-55 Hydrodynamic YES NO Analysis Options Nov 02, 2022 00:00:00 Nov 03, 2022 00:00:00 Nov 02, 2022 00:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 30 seconds Number of Elements Qty 3 1 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0 Rainfall Details SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall ID Source ID Type Units Period Depth Distribution (years)(inches) 1 Rain Gage-010y Time Series TS-03 Cumulative inches Washington King 10 2.90 SCS Type IA 24-hr 2 Rain Gage-025y Time Series TS-01 Cumulative inches Washington King 25 3.40 SCS Type IA 24-hr 3 Rain Gage-100y Time Series TS-02 Cumulative inches Washington King 100 3.90 SCS Type IA 24-hr Outlets ......................................................... Pollutants ............................................................. Land Uses ............................................................ Links...................................................................... Channels ..................................................... Pipes ............................................................ Pumps ......................................................... Orifices ........................................................ Weirs ........................................................... Nodes.................................................................... Junctions ..................................................... Outfalls ........................................................ Flow Diversions ........................................... Inlets ............................................................ Storage Nodes ............................................. Runoff (Dry Weather) Time Step ......................... Runoff (Wet Weather) Time Step ........................ Reporting Time Step ............................................ Routing Time Step ............................................... Rain Gages .......................................................... Subbasins............................................................. Enable Overflow Ponding at Nodes ..................... Skip Steady State Analysis Time Periods ............ Start Analysis On ................................................. End Analysis On ................................................... Start Reporting On ............................................... Antecedent Dry Days ........................................... File Name ............................................................. Flow Units ............................................................ Elevation Type ..................................................... Hydrology Method ................................................ Time of Concentration (TOC) Method ................. Link Routing Method ............................................ Subbasin Summary SN Subbasin Area Impervious Impervious Pervious Total Total Total Peak Time of ID Area Area Curve Area Curve Rainfall Runoff Runoff Runoff Concentration Number Number Volume (ac)(%)(in)(in)(ac-in)(cfs)(days hh:mm:ss) 1 Sub-01 3.63 74.00 98.00 86.00 2.90 2.36 8.56 1.62 0 00:26:10 10-Year Peak Subbasin Hydrology Subbasin : Sub-01 Input Data Area (ac) ........................................................................3.63 Impervious Area (%) ......................................................74.00 Impervious Area Curve Number ....................................98.00 Pervious Area Curve Number ........................................86.00 Rain Gage ID .................................................................Rain Gage-010y Composite Curve Number Area Soil Curve Soil/Surface Description (acres)Group Number Composite Area & Weighted CN 3.63 94.88 Time of Concentration TOC Method : SCS TR-55 Sheet Flow Equation : Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where : Tc = Time of Concentration (hr) n = Manning's roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation : V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hr) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation : V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where : Tc = Time of Concentration (hr) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's roughness User-Defined TOC override (minutes): 26.17 Subbasin Runoff Results Total Rainfall (in) ............................................................2.90 Total Runoff (in) .............................................................2.36 Peak Runoff (cfs) ...........................................................1.62 Weighted Curve Number ...............................................94.88 Time of Concentration (days hh:mm:ss) ........................0 00:26:10 Subbasin : Sub-01 Subbasin Summary Subbasin Area Impervious Impervious Pervious Total Total Total Peak Time of ID Area Area Curve Area Curve Rainfall Runoff Runoff Runoff Concentration Number Number Volume (ac)(%)(in)(in)(ac-in)(cfs)(days hh:mm:ss) Sub-01 3.63 74.00 98.00 86.00 3.89 3.32 12.03 2.28 0 00:26:10 100-Yr Peak Subbasin Hydrology Subbasin : Sub-01 Input Data Area (ac) .............................................................................3.63 Impervious Area (%) ............................................................74 Impervious Area Curve Number ..........................................98 Pervious Area Curve Number ..............................................86 Rain Gage ID .......................................................................Rain Gage-02 Composite Curve Number 32 Area Soil Curve Soil/Surface Description (acres)Group Number Composite Area & Weighted CN 3.63 94.88 Time of Concentration TOC Method : SCS TR-55 Sheet Flow Equation : Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where : Tc = Time of Concentration (hr) n = Manning's roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation : V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hr) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation : V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where : Tc = Time of Concentration (hr) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's roughness User-Defined TOC override (minutes): 26.17 Subbasin Runoff Results Total Rainfall (in) .................................................................3.89 Total Runoff (in) ..................................................................3.32 Peak Runoff (cfs) .................................................................2.28 Weighted Curve Number .....................................................94.88 Time of Concentration (days hh:mm:ss) ..............................0 00:26:10 Subbasin : Sub-01 Rainfall Intensity Graph Time (hrs) 2423222120191817161514131211109876543210Rainfall (in/hr)0.95 0.9 0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Runoff Hydrograph Time (hrs) 2423222120191817161514131211109876543210Runoff (cfs)2.4 2.3 2.2 2.1 2 1.9 1.8 1.7 1.6 1.5 1.4 1.3 1.2 1.1 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 2,400400 City of Renton Print map Template This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 11/02/2022 Legend 272 0 136 272 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Labels Addresses Parcels City and County Boundary <all other values> Renton Fence Facility Transfer Streets Points of Interest Parks Waterbodies 2021.sid Red: Band_1 Green: Band_2 Blue: Band_3 Project Site Basin Auguilar Residence Catch Basin OFFSITE BASIN MAP PROJECT: __________________________________________ SHEET NO: _____ OF _____ BY: ________________________________________________ TASK: ______________________________________________ DATE: ____________________ Distance from Park Ave to SDCB #505632: 1,204 FT. Lot depth: 108 FT Dedication: 1.5 FT Percentage Impervious Area: 75% Percentage Pervious Pasture: 25% Total Lot Impervious Area: (.75)(1204)(108-1.5) = 96,170 SF Total Lot Pervious Area: (.25)(1204)(108-1.5) = 32,060 SF Distance from Park Ave to SDCB #505632: 1204 FT. Width of street section: 26.5 FT Percentage Impervious Area: 70% Percentage Pervious Pasture: 30% Total Street Impervious Area: (.70)(1204)(26.5) = 22,334 SF Total Street Pervious Area: (.30)(1204)(26.5) = 9,572 SF Total Basin Areas: Pervious: 41,632 SF Impervious: 118,504 SF Percent Impervious: 74% 22073 Aguilar Residence Dual Vaned/Combination Grate Capacity Analysis Noah Burlingame 1 3 11/23/2022 PROJECT: __________________________________________ SHEET NO: _____ OF _____ BY: ________________________________________________ TASK: ______________________________________________ DATE: ____________________ Calculation: Dual vaned grate is 75% free:PN = .75 [(2*2.58 ft) + 2*(1.29)] = 5.81-ft 22073 Aguilar Residence Dual Vaned Grate Local Low Point (Sag) Capacity Analysis (Option A) Noah Burlingame 2 3 11/23/2022 Calculation: Qallowable = (3.0) x (5.81-ft) x (0.267-ft)^1.5 = 2.40 cfs (3.2 inches of ponding at inlet) The effective perimeter for the proposed dual vaned grate will be equal to the sum of all four sides of the grate. This is because thegrate will be separated from the curb, thus allowing the grate toreceive flow from all four sides. PROJECT: __________________________________________ SHEET NO: _____ OF _____ BY: ________________________________________________ TASK: ______________________________________________ DATE: ____________________ Calculation: Combination inlet is 100% free per WSDOT hydraulics manual:PN = 1*[(1.25 ft + 2*(1.31/2)] = 2.56-ft 22073 Aguilar Residence Combination Local Low Point (Sag) Capacity Analysis (Option B) Noah Burlingame 3 3 11/23/2022 Calculation: Qallowable = (3.0) x (2.56-ft) x (0.458-ft)^1.5 = 2.38 cfs (5.5 inches of ponding at inlet) Grate Analyses Summary 2019 INLET SPACING - CURB AND GUTTER SPREADSHEET (ENGLISH UNITS) FULL BASIN PEAK FLOWS Tc = *NA Project Name: N 35th St Drainge for Aguilar Residence Street Cross Slope 10-yr Type 1A 24-hr Peak 1.62 C = *NA Project #: 22073 Location 1:100.84 101.14 101.14 Location 2: 93.496 25-yr Type 1A 24-hr Peak 1.95 I = *NA S.R.: NA 99.72 99.26 99.72 93.22 100-yr Type 1A 24-hr Peak 2.28 m=*NA Designed By:Andy Epstein 11.21 22.59 17.04 13.08 n=*NA Date:6/14/2023 10.0%8.34%2.11% Scenario Slope *10-year and 100-year flows calculated outside of this spreadsheet and entered here.Long. Slope Longitudinal Road Slope:0.071 10-year; 3.5% Cross Slope 0.035 350.0% 100-year; 3.5% Cross Slope 0.035 350.0% Structure ID Station Distance (ft) Width (ft) Area (ft2) D Q cfs (cfs) S Q (cfs) Slope L (ft/ft) Super T (ft/ft) Grate Type HM Figure 5-11 GRATE WIDTH (ft) GRATE LENGTH (ft)Roadway Classification Enter Requested Information Allowable Spread Policy Driving Lane Width (ft) Shoulder Width (ft) Allowable Zd (ft) Calculated Zd (ft) Depth of Flow at Face of Curb d (inches) Manning's n for Street and Pavement Gutter Velocity fo Gutter Flow (ft/sec) Ratio of Frontal Flow to Total Gutter Flow Eo Splash- Over Velocity Vo (ft/sec) Frontal Flow Intercept ed to Full Frontal Flow Rf Ratio of Side Flow Intercepted to Total Side Flow Rs Effiency of Grate E Qi (cfs) Qbp (cfs)Zd Check Qbp Check 10-year; 3.5% Cross Slope Dual Vaned Rotated; 10- year; 3.5% Cross Slope 0+01.00 NA NA 1.62 1.62 0.071 0.035Standard Plan B-40.40-02 Frame and Dual Vaned Grates for Grate Inlet (Rotated) 3.52 1.75 Collector and Local Streets Enter Speed (mph) ---------------> 35 Shoulder + 1/2 Driving Lane 13.00 0.00 6.50 4.23 1.78 0.016 5.14 0.99 7.10 1.00 0.04 0.99 1.61 0.01 Zd Allowable > Zd Design Qbp < 0.1 CFS 100-year; 3.5% Cross Slope Dual Vaned Rotated; 100- year; 3.5% Cross Slope 0+01.00 NA NA 2.28 2.28 0.071 0.035Standard Plan B-40.40-02 Frame and Dual Vaned Grates for Grate Inlet (Rotated) 3.52 1.75 Collector and Local Streets Enter Speed (mph) ---------------> 35 Shoulder + 1/2 Driving Lane 13.00 0.00 6.50 4.81 2.02 0.016 5.60 0.97 7.10 1.00 0.04 0.97 2.21 0.07 Zd Allowable > Zd Design Qbp < 0.1 CFS Fill in the data for the grey shaded areas only V6.2 Revised 9/13/2019 AGUILAR RESIDENCE (22073) ETHOS CIVIL Page 39 of 39 APPENDIX G – STORM MAIN CONVEYANCE CALCULATIONS 2,400400 City of Renton Print map Template This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. THIS MAP IS NOT TO BE USED FOR NAVIGATIONWGS_1984_Web_Mercator_Auxiliary_Sphere Notes None 11/02/2022 Legend 272 0 136 272 Feet Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Labels Addresses Parcels City and County Boundary <all other values> Renton Fence Facility Transfer Streets Points of Interest Parks Waterbodies 2021.sid Red: Band_1 Green: Band_2 Blue: Band_3 Project Site Auguilar Residence Proposed 12" Storm Main Basin Total: 7.62 AC 138,515.2 sf 137,157.2 sf 60,984.86 sf Proposed Catch Basin Conceptual Future Storm Main Off-site Basin Map Project Description 22073 SSA.SPF Project Options CFS Elevation Santa Barbara UH SCS TR-55 Hydrodynamic YES NO Analysis Options 00:00:00 0:00:00 00:00:00 0:00:00 00:00:00 0:00:00 0 days 0 01:00:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 0 00:05:00 days hh:mm:ss 30 seconds Number of Elements Qty 3 1 2 1 1 0 0 0 1 0 1 0 0 0 0 0 0 Rainfall Details SN Rain Gage Data Data Source Rainfall Rain State County Return Rainfall Rainfall ID Source ID Type Units Period Depth Distribution (years)(inches) 1 Rain Gage-010y Time Series TS-03 Cumulative inches Washington King 10.00 2.90 SCS Type IA 24-hr 2 Rain Gage-025y Time Series TS-01 Cumulative inches Washington King 25.00 3.40 SCS Type IA 24-hr 3 Rain Gage-100y Time Series TS-02 Cumulative inches Washington King 100.00 3.90 SCS Type IA 24-hr Antecedent Dry Days ......................................... File Name .......................................................... Flow Units .......................................................... Elevation Type ................................................... Hydrology Method ............................................. Time of Concentration (TOC) Method ................ Link Routing Method ......................................... Enable Overflow Ponding at Nodes .................... Skip Steady State Analysis Time Periods ............. Start Analysis On ................................................ End Analysis On ................................................. Start Reporting On ............................................. Storage Nodes ........................................... Runoff (Dry Weather) Time Step ........................ Runoff (Wet Weather) Time Step ....................... Reporting Time Step .......................................... Routing Time Step .............................................. Rain Gages ......................................................... Subbasins............................................................ Nodes................................................................. Junctions .................................................... Outfalls ...................................................... Flow Diversions .......................................... Inlets .......................................................... Outlets ....................................................... Pollutants .......................................................... Land Uses .......................................................... Links................................................................... Channels .................................................... Pipes .......................................................... Pumps ........................................................ Orifices ....................................................... Weirs ......................................................... Subbasin Summary Subbasin Area Impervious Impervious Pervious Total Total Total Peak Time of ID Area Area Curve Area Curve Rainfall Runoff Runoff Runoff Concentration Number Number Volume (ac)(%)(in)(in)(ac-in)(cfs)(days hh:mm:ss) Sub-01 7.62 80.00 98.00 86.00 3.39 2.90 22.13 4.21 0 00:26:10 Node Summary Element Element Invert Ground/Rim Ponded Peak Max HGL Min Time of Total Total Time ID Type Elevation (Max)Area Inflow Elevation Freeboard Peak Flooded Flooded Elevation Attained Attained Flooding Volume Occurrence (ft)(ft)(ft²)(cfs)(ft)(ft)(days hh:mm)(ac-in)(min) 2-Jun Junction 0.00 6.00 0.00 4.21 1.78 4.22 0 00:00 0.00 0.00 Out-01 Outfall 0.00 4.21 0.79 Link Summary Element From To (Outlet)Length Inlet Outlet Average Diameter or Manning's Peak Design Flow Peak Flow Peak Flow Total Time Reported Type (Inlet)Node Invert Invert Slope Height Roughness Flow Capacity Velocity Depth Surcharged Condition Node Elevation Elevation (ft)(ft)(ft)(%)(in)(cfs)(cfs)(ft/sec)(ft)(min) Pipe 2-Jun Out-01 25.00 0.50 0.00 2.0000 12.000 0.0150 4.21 4.37 5.68 0.89 0.00 Calculated Subbasin Hydrology Subbasin : Sub-01 Input Data Area (ac) ...............................................................................7.62 Impervious Area (%) .............................................................80 Impervious Area Curve Number ...........................................98 Pervious Area Curve Number ...............................................86 Rain Gage ID .........................................................................Rain Gage-025y Composite Curve Number 32 Area Soil Curve Soil/Surface Description (acres)Group Number Composite Area & Weighted CN 7.62 95.6 Time of Concentration TOC Method : SCS TR-55 Sheet Flow Equation : Tc = (0.007 * ((n * Lf)^0.8)) / ((P^0.5) * (Sf^0.4)) Where : Tc = Time of Concentration (hr) n = Manning's roughness Lf = Flow Length (ft) P = 2 yr, 24 hr Rainfall (inches) Sf = Slope (ft/ft) Shallow Concentrated Flow Equation : V = 16.1345 * (Sf^0.5) (unpaved surface) V = 20.3282 * (Sf^0.5) (paved surface) V = 15.0 * (Sf^0.5) (grassed waterway surface) V = 10.0 * (Sf^0.5) (nearly bare & untilled surface) V = 9.0 * (Sf^0.5) (cultivated straight rows surface) V = 7.0 * (Sf^0.5) (short grass pasture surface) V = 5.0 * (Sf^0.5) (woodland surface) V = 2.5 * (Sf^0.5) (forest w/heavy litter surface) Tc = (Lf / V) / (3600 sec/hr) Where: Tc = Time of Concentration (hr) Lf = Flow Length (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) Channel Flow Equation : V = (1.49 * (R^(2/3)) * (Sf^0.5)) / n R = Aq / Wp Tc = (Lf / V) / (3600 sec/hr) Where : Tc = Time of Concentration (hr) Lf = Flow Length (ft) R = Hydraulic Radius (ft) Aq = Flow Area (ft²) Wp = Wetted Perimeter (ft) V = Velocity (ft/sec) Sf = Slope (ft/ft) n = Manning's roughness User-Defined TOC override (minutes): 26.17 Subbasin Runoff Results Total Rainfall (in) ..................................................................3.39 Total Runoff (in) ...................................................................2.9 Peak Runoff (cfs) ..................................................................4.21 Weighted Curve Number ......................................................95.6 Time of Concentration (days hh:mm:ss) ...............................0 00:26:10 Subbasin : Sub-01 Rainfall Intensity Graph Time (hrs) 2423222120191817161514131211109876543210Rainfall (in/hr)0.85 0.8 0.75 0.7 0.65 0.6 0.55 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Runoff Hydrograph Time (hrs) 23222120191817161514131211109876543210Runoff (cfs)4.6 4.4 4.2 4 3.8 3.6 3.4 3.2 3 2.8 2.6 2.4 2.2 2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 Junction Input Element Invert Ground/Rim Initial Initial Surcharge Surcharge Ponded Minimum ID Elevation (Max)Water Water Elevation Depth Area Pipe Elevation Elevation Depth Cover (ft)(ft)(ft)(ft)(ft)(ft)(ft²)(in) 2-Jun 0.00 6.00 0.00 0.00 6.00 0.00 0.00 0.00 Pipe Input Length Inlet Outlet Average Pipe Manning's Entrance Exit/Bend Invert Invert Slope Diameter or Roughness Losses Losses Elevation Elevation Height (ft)(ft)(ft)(%)(in) 48 0.50 0.00 2.00 48 0.0150 0.50 0.50