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Home My WebLink AboutAPPROVED_Skattum Renton Plat TIR_230630Civil Engineering & Development Services 1700 NW Gilman BLVD, STE 200; Issaquah, WA 98027 (425) 821-5038 Email: Info@G2CIVIL.COM TECHNICAL INFORMATION REPORT CITY OF RENTON For Stein Skattum P.O. Box 769 Renton, WA 98057 September 30, 2022 Prepared By: Lauren Elliott Prepared For: Stein Skattum PO Box 769 Renton, WA 98057 SURFACE WATER UTILITY jfarah 06/22/2023 DEVELOPMENT ENGINEERING Michael Sippo 06/30/2023 Skattum Renton Plat Technical Information Report 9/30/2022 Page i Contents SECTION 1: Project Overview .......................................................................................................... 5 SECTION 2: Core and Special Requirements Summary ................................................................ 10 SECTION 3: Offsite Analysis ........................................................................................................... 11 SECTION 4: Flow Control and water quality Facility Analysis and Design .................................... 16 SECTION 5: Conveyance System Analysis and Design .................................................................. 20 SECTION 6: Special Reports and Studies ....................................................................................... 26 SECTION 7: Other Permits ............................................................................................................. 26 SECTION 8: CSWPP Analysis and Design ....................................................................................... 26 SECTION 9: Bond Quantities, Facility Summaries, and Declaration of Covenant ......................... 27 SECTION 10: Operations and Maintenance Manual ..................................................................... 27 FIGURES Figure 1 – TIR Worksheet Figure 2 – Vicinity Map Figure 3 – Soils Map Figure 4 – Drainage Basin & Site Characteristics Figure 5A & 5B – Downstream Mapping Figure 6 – Offsite Area Tributary to Bypass System APPENDICIES Appendix A – WWHM Analysis Appendix B – Operations & Maintenance Manual Appendix C – Geotechnical Report Appendix D – Arborist Report Appendix E – Wetland & Stream Reconnaissance Appendix F – Bond Quantity Worksheet Appendix G – Declaration of Covenant for Privately Maintained Flow Control and Water Quality Features Appendix H – Flow Control & Water Quality Facility Summary Sheet & Sketch Appendix I – Backwater Analysis KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 1 Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner ________________________ Phone ______________________________ Address ____________________________ ____________________________________ Project Engineer ______________________ Company ___________________________ Phone ______________________________ Project Name _________________________ DDES Permit # ________________________ Location Township ______________ Range ________________ Section ________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS Landuse Services Subdivison / Short Subd. / UPD Building Services M/F / Commerical / SFR Clearing and 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 (circle): Date (include revision dates): Date of Final: Full / Targeted / Large Site ___________________ ___________________ ___________________ Type (circle one): Date (include revision dates): Date of Final: Full / Modified / Small Site __________________ __________________ __________________ Part 6 ADJUSTMENT APPROVALS Type (circle one): Standard / Complex / Preapplication / Experimental / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Date of Approval: ______________________ Nicole Mecum, PE G2 Civil 425-821-5038 9-30-22 Stein Skattum (206) 300-6231 10350 Rainier Avenue S Seattle, WA 98178 Renton Subdivision 23N 5E 29 17018 & 17022 106th Ave SE Renton, WA 98055 x x 9-24-18 Civil Construction Permit 9-24-18 5-18-21 5-18-21 9-30-22 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 2 Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ _________________________________________ _________________________________________ 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 __________________ _________________________________ Part 10 SOILS Soil Type _________________ _________________ _________________ _________________ Slopes _________________ _________________ _________________ _________________ Erosion Potential _________________ _________________ _________________ _________________ High Groundwater Table (within 5 feet) Other ________________________ Sole Source Aquifer Seeps/Springs Additional Sheets Attached Soos Creek Black River AgC, Alderwood Minimal0-15% KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 3 Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE Core 2 – Offsite Analysis_________________ Sensitive/Critical Areas___________________ SEPA________________________________ 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 (incl. facility summary sheet) Level: 1 / 2 / 3 or Exemption Number ____________ Small Site BMPs ___________________________________ Conveyance System Spill containment located at: _________________________ Erosion and Sediment Control ESC Site Supervisor: Contact Phone: After Hours Phone: Maintenance and Operation Responsibility: Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type: Basic / Sens. Lake / Enhanced Basicm / Bog or Exemption No. ______________________ Landscape Management Plan: Yes / No Special Requirements (as applicable) Area Specific Drainage Requirements Type: CDA / SDO / MDP / BP / LMP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type: Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): ______________ Datum: Flood Protection Facilities Describe: Source Control (comm./industrial landuse) Describe landuse: Describe any structural controls: Project Site 1 1-27-15 TBD N/A N/A FC/WQ Facility & ROW Conveyance - Public On-site Conveyance - Private KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 4 Oil Control High-use Site: Yes / No Treatment BMP: ________________________________ Maintenance Agreement: Yes / No with whom? ____________________________________ Other Drainage Structures Describe: Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION Clearing Limits Cover Measures Perimeter Protection Traffic Area Stabilization Sediment Retention Surface Water Collection Dewatering Control Dust Control Flow Control MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION Stabilize Exposed Surfaces Remove and Restore Temporary ESC Facilities Clean and Remove All Silt and Debris, Ensure Operation of Permanent Facilities Flag Limits of SAO and open space preservation areas Other ______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description Detention Infiltration Regional Facility Shared Facility Flow Control BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ Biofiltration Wetpool Media Filtration Oil Control Spill Control Flow Control BMPs Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ x x x x x x x x Vault Wetvault x KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2009 Surface Water Design Manual 1/9/2009 5 Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS Drainage Easement Covenant Native Growth Protection Covenant Tract Other Cast in Place Vault Retaining Wall Rockery > 4’ High Structural on Steep Slope Other Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. Signed/Date x x 9-30-22 Skattum Renton Plat Technical Information Report 9/30/2022 Page 6 SECTION 1: Project Overview This Technical Information Report is submitted in support of the Renton Subdivision Plat. The project site consists of 2 parcels; KC Parcel #’s 0087000265 and 0087000270. The properties are rectangular in shape and are located on the east side of 106th Avenue SE (See Figure 1 - Vicinity Map below). The property is bordered along the north, south, and east by single family residences. The project area is approximately 1.94 acres and is presently developed with 2 single- family residences. The existing buildings and driveways will be removed. Project site improvements will consist of on & off-site infrastructure improvements to support the future construction of 11 single family residential building lots and new public road. Frontage improvements will include the installation of an 8’ wide planter strip and a 5’ wide sidewalk along 106th Avenue SE. Figure 2 – Vicnity Map SITE Skattum Renton Plat Technical Information Report 9/30/2022 Page 7 Soils: The SCS Soils map indicates the site is underlain with AgC (Alderwood) soils. Figure 3 – Soils Map Skattum Renton Plat Technical Information Report 9/30/2022 Page 8 Figure 4a – Drainage Basin and Site Characteristics USGS Topographic Map (Contour interval = 20 feet) SITE Point of Discharge to public conveyance system (approx. 315 feet south of the site) Skattum Renton Plat Technical Information Report 9/30/2022 Page 9 Figure 4b – Drainage Basin and Site Characteristics PROJECT SITE (2.1 AC) Site Discharge Point Existing Conveyance Ditch* *Existing conveyance ditch from the Marvin Gardens Townhomes vault. Ditch to be filled and 8” PVC to be installed to convey runoff to the natural discharge point. Please refer to Developed Conditions Map on page 15. Proposed Detention/Water Quality Vault Offsite flows, typ. Farthest upstream end of proposed storm system (390 LF to flow control facility) Skattum Renton Plat Technical Information Report 9/30/2022 Page 10 SECTION 2: Core and Special Requirements Summary To obtain preliminary approval with the City of Renton, the relevancy of the 9 core and 6 special requirements per the 2017 City of Renton Surface Water Design Manual are required to be addressed: 1. Core Req. #1 – Discharge at natural location A field review of the site-specific topography indicates that the developed drainage will discharge to the natural location situated downstream to the south of the project site. 2. Core Req. #2 – Offsite Analysis An off-site analysis has been prepared for approval by the City of Renton, See Section 3. 3. Core Req. #3 – Flow Control Flow control will be provided for the development via a detention vault. See Section 4. 4. Core Req. #4 – Conveyance System The proposed on-site conveyance and tightline system will route runoff to the existing conveyance system within 106th AVE SE. 5. Core Req. #5 – Construction Stormwater Pollution Prevention An erosion and sediment control plan, which will serve to minimize soil erosion/sedimentation during the proposed site construction, will be prepared for approval by the City of Renton. 6. Core Req. #6 – Maintenance and Operations The on-site stormwater system will be maintained by the homeowners. The off-site conveyance systems will be maintained by the City of Renton. See Appendix B. 7. Core Req. #7 – Financial Guarantees & Liability Financial Guarantee & Liability commitments between the property developer and the City of Renton will be established at the time of permit issuance. 8. Core Req. #8 – Water Quality Facilities The proposed pollution generating impervious surfaces are greater than 5,000 SF, therefore water quality treatment is required. The project proposes a combined detention and wetvault system to meet the water quality requirement. 9. Core Req. #9 – On-Site BMPs Proposed on-site BMPs include reduced footprints. Please refer to Section 4 for more detail. 10. Special Req. #1 – Other Adopted Area-Specific Requirements The 2017 City of Renton SWDM was reviewed and there are no additional requirements. 11. Special Req. #2 – Flood Hazard Area Delineation Per City of Renton mapping the site does not lie within a floodplain, zero-rise flood fringe, zero-rise floodway or FEMA floodway. 12. Special Req. #3 – Flood Protection Facilities Not applicable to this project. 13. Special Req. #4 – Source Controls Not applicable to this project Skattum Renton Plat Technical Information Report 9/30/2022 Page 11 14. Special Req. #5 – Oil Control This project is not considered high-use therefore oil control is not applicable to this project. 15. Special Req. #6 – Aquifer Protection Area Not applicable to this project per Reference 15-B in the City of Renton SWDM. SECTION 3: Offsite Analysis A field review of the downstream conditions was performed on January 27, 2015. The weather was sunny and wet; the temperature was approximately 55 degrees. A visual reconnaissance was performed utilizing information obtained from the City of Renton GIS Mapping. Please refer to storm drainage mapping exhibits that follow for a depiction of the downstream drainage conditions. Upstream: A detention vault constructed for the Marvin Garden Townhomes project is located east of the Skattum properties and presently discharges to a ditch located near the northeast property corner. Drainage from this system will be collected and conveyed along the east and south property lines to bypass the Skattum Plat’s detention vault. The upstream flow from the existing ditch located along the eastern side of 106th Ave SE and sheet flow from the properties to the north and east will be collected and bypass the proposed detention vault. Refer to Figure 5A for a depiction of the upstream and downstream flows. Refer to Section 6 for additional information regarding the bypassed area. Downstream: The runoff is tributary to the existing ditch to the west of the site. The ditch conveys runoff to the south for approximately 320 feet before crossing SE 172nd Street via an existing closed pipe conveyance system for 68 feet. Runoff then appears to sheet flow down the hill to an existing ditch along the north side of Benson Drive South before entering an existing closed pipe conveyance system. The conveyance system directs runoff to the west for 80 feet where runoff then enters a ditch and continues west for approximately 400 feet. Runoff is then directed to the southwest for approximately 580 feet via a closed pipe system within South 36th Street. The field Skattum Renton Plat Technical Information Report 9/30/2022 Page 12 reconnaissance was terminated as the investigation exceeded the required ¼ mile point analysis. Downstream Concerns & Effects of Proposed Project: Drainage from the developed site will be collected and detained onsite prior to being discharged to the public conveyance system within 106th Ave SE. In order for the proposed vault to completely buried, as required by the City, the existing conveyance system within 106th Ave SE will be removed and replaced to the intersection of SE 172nd Street (approximately 320 feet replaced). The existing ditch will be restored. The downstream appears capable of conveying the release rates associated with the project. Significant impacts to the downstream system are not anticipated, as no significant signs of drainage related problems were observed during the field reconnaissance. Resource Review: The following list from the 2016 KCSWDM Resource Review was reviewed: Basin Plan - There is no known Adopted Basin Plan for this area. Floodplain Map – Per FEMA Flood Map Number 53033C0979F the site is located outside the floodplains. Other Offsite Analysis Reports - No additional other reports were reviewed in preparation of this report. Sensitive Areas - The City of Renton Critical Areas Map was reviewed and there are no sensitive areas on-site. Downstream Complaints – King County iMap was used to view downstream complaints. All downstream drainage complaints are greater than 10 years old. Per KCSWDM Section 2.3.1.1 any complaints older than 10 years are not relevant to a Level One Downstream Analysis. However, per City of Renton comments, there has been a compliant regarding flooding at the trach rock inlet located near 1235 South 36th Street. This area was observed on November 30, 2021 after days of heavy rainfall. Based on record drawings, this area outlets to the conveyance system within Cedar Ave S/S 36th St and has an overflow to a swale that discharges to the same system. No signs of flooding were observed during the field visit. Based on the observed amount of debris in the surrounding area, see photos on the following page, it is assumed the previous flooding may have been caused by debris build up blocking the outlet and emergency swale birdcage. This area should be regularly maintained to prevent blockage. The system is within public ROW and should be maintained by the City of Renton. Road Drainage – See above. King County Soils Survey - The existing on-site soils are AgC – gravelly sandy loam per the US Department of Agriculture. Wetlands Inventory - There are no wetlands on or adjacent to the site per the Wetland and Stream reconnaissance prepared by Altman Oliver Associates, LLC. Please refer to Appendix E. Migrating River Studies - There are no known migrating rivers in the resource review area. Section 303d list of polluted waters – Based on the Water Quality Assessment link on the DOE website, there is an unnamed creek approximately ½ mile downstream from the site that is listed as a Category 5 water for bioassessment. KC designated water quality problems - There are no known water quality problems within the area. Stormwater compliance plans - Not applicable to this project. Skattum Renton Plat Technical Information Report 9/30/2022 Page 13 Figure 5A – Downstream Mapping (City of Renton GIS) Figure 5B – Downstream Mapping (City of Renton GIS) Marvin Gardens Townhomes vault SITE Match Line Match Line Bypass system for offsite flow Proposed interceptor swale for upstream flows to bypass vault Bypass system for offsite flows Flooding concern area per City comments Skattum Renton Plat Technical Information Report 9/30/2022 Page 14 Drainage Concern Photo Locations Reference Photo #1&2 Photo #4 Photo #3 Skattum Renton Plat Technical Information Report 9/30/2022 Page 15 Photo #1: Looking NE Photo #2: Looking South Photo #3: Looking North Photo #4: Looking South Skattum Renton Plat Technical Information Report 9/30/2022 Page 16 SECTION 4: Flow Control and Water Quality Facility Analysis and Design A formal flow control facility is required for the project site based on Section 1.2.3 of the City of Renton Surface Water Design Manual (SWDM). According to the Flow Control Application Map in the City of Renton SWDM, Reference 15-A, the project site is located within the Flow Control Duration Standard (Forested Conditions). This flow control standard is equivalent to the Conservation Flow Control Area in the Renton SWDM which utilizes historic site conditions for the predeveloped flow rates. A combined detention and wetvault is proposed to meet the Flow Control and Water Quality Requirements. A hydrologic analysis of the site was completed in order to size the required on-site detention and water quality treatment necessary to account for the increase in the peak storm water release rate for the developed site. The site was analyzed for the pre-developed and developed conditions under the Western Washington Hydrology Model (WWHM) using the WWHM2012 software developed and provided by the Department of Ecology. Below are the areas used in the analysis; please refer to Appendix A for the complete WWHM analysis. Given the site topography approximately 1,839 SF of the improved 106th Ave SE ROW could not be conveyed to the detention vault. Therefore 1,839 SF of the existing road drainage from the west side of 106th Ave NE in front of the project will be collected and conveyed to the detention vault. Refer to page 17 for more detail. As described in Section 3 of this report, the offsite upstream flows will be collected and bypass the proposed vault. Refer to the Predeveloped and Developed Conditions Maps on the following pages for additional information. Predeveloped Conditions: On-Site: Area Forest = 1.611 acre Off-Site (106th Ave SE & Road A): Area Forest = 0.490 acre Total Project (On & Off-Site) Area Forest = 2.101 acre Developed Conditions: On-Site: Impervious (Max per Zoning, 65%) = 1.047 acre Pervious = 0.564 acre Total Onsite = 1.611 acre Off-Site: Impervious = 0.365 acre Pervious = 0.125 acre Total Offsite = 0.490 acre Total Project (On & Off-Site) Impervious = 1.412 acre Pervious = 0.689 acre Total Project Area = 2.101 acre Skattum Renton Plat Technical Information Report 9/30/2022 Page 17 Predeveloped Conditions Map Project Area SF AC Forest = 70,178 1.611 Total Area = 70,178 1.611 Forest = 21,336 0.490 Total Area = 21,336 0.490 Forest = 91,514 2.101 Total Area = 91,514 2.101 Predeveloped Areas Table Onsite (After ROW Dedication): Offsite (After ROW Dedication): Total Site: Skattum Renton Plat Technical Information Report 9/30/2022 Page 18 Developed Conditions Map (Refer to Appendix A for a larger figure) SF AC Untreated Project Area 1,839 0.042 Treated Non-Project Area 1,839 0.042 Mitigation Trade Areas Table: Untreated Project Area Treated Non-Project Area Project Area SF AC Impervious (Max per Zoning) = 45,616 1.047 Pervious = 24,562 0.564 Total Area = 70,178 1.611 Impervious = 15,907 0.365 Pervious = 5,429 0.125 Total Area = 21,336 0.490 Impervious = 61,523 1.412 Pervious = 29,991 0.688 Total Area = 91,514 2.101 Developed Areas Table Onsite: Offsite (106th Ave SE & SE 170th Pl): Total Site: Skattum Renton Plat Technical Information Report 9/30/2022 Page 19 Mitigated Area Trade: As previously noted, given the site topography approximately 1,839 SF of the improved 106th Ave SE ROW cannot be conveyed to the detention vault. Therefore 1,839 SF of the existing road drainage from the west side of 106th Ave NE in front of the project will be collected and conveyed to the detention vault. Refer to the Developed Conditions Exhibit on Page X for a depiction of the mitigation trade areas. Per Section 1.2.3.2.G of the 2017 Renton Surface Water Design Manual mitigation trades are allowed provided that; 1. The existing developed non-target surface area must have runoff discharge characteristics equivalent to those of the target surface area for which mitigation is being traded and must not be currently mitigated to the same flow control performance requirement as the target surface area. • Both areas area paved surfaces with a relatively flat slope, therefore the drainage characteristics are equivalent. 2. Runoff from both the target surface area being traded and the flow control facility must converge prior to discharge of the runoff from the target surface area being traded onto private property without an easement or through any area subject to erosion. • Runoff from the target surface and the flow control facility converge within 106th Ave NE. 3. The net effect in terms of flow control at the point of convergence downstream must be the same with or without the mitigation trade. • The non-target surface area and target surface area being traded currently flow to the convergence point. By collecting the non-target surface area and routing it to the flow control facility, the net effect at the convergence point will be the same. 4. The undetained runoff from the target surface area being traded must not create a significant adverse impact to the downstream drainage systems, salmonid habitat, or properties prior to convergence with runoff from the flow control facility. • The undetained target surface runoff converges with the runoff from the flow control facility at the flow control facility’s connection to the public conveyance system within 106th Ave NE located adjacent to the site. Therefore, adverse impacts to the downstream system from the undetained target surface runoff is not anticipated. 5. Consideration of an offsite area to be mitigated for must take into account the likelihood of that area redeveloping in the future. Those areas determined by the City to have a high likelihood of future redevelopment that will provide its own mitigation may not be used as a mitigation trade. • In the event that the road is redeveloped in the future, it is likely that the area would still drain to the proposed flow control system. Skattum Renton Plat Technical Information Report 9/30/2022 Page 20 6. Mitigation trade proposals must be reviewed and approved with input from the City of Renton. • Understood. Water Quality: The proposed pollution generating impervious surfaces are greater than the 5,000 SF threshold, therefore water quality treatment is required for this project. The area-specific water quality treatment was determined to be Basic. The project proposes a combined detention and wetvault system to meet the water quality requirement. The storm water facility incorporates and provides a two-cell basic wet vault into the design of the storm water control and treatment facility by providing additional storage volume below the detention vault volume. The wet vault was designed as detailed in the 2017 Renton Surface Water Design Manual Section 6.4.1.1 and is equal to 91% water quality treatment volume calculated with the approved model. This volume per WWHM is 0.1949 acre-feet or 8,477 CF. The proposed vault is 42.5’ by 68.5’ and provides 31,296 CF of live storage and 10,917 CF of dead storage. Refer to Appendix A for the complete WWHM Analysis. A sketch of the proposed facility is included in Appendix H. Flow Control BMP Analysis: Per the 2017 City of Renton Surface Water Design Manual Section 1.2.9, all proposed projects must provide on-site BMPs to mitigate the impacts of storm and surface water runoff generated by the development. The feasibility and applicability of flow control BMPs are detailed below. 1. Full Dispersion is infeasible due to the lack of native vegetated surface available to be preserve. 2. Full Infiltration is infeasible; based on the Geotechnical Engineering Study prepared by Earth Solutions NW. The study states that the onsite soils (medium dense to dense glacial till) are not considered an ideal geologic feature for accommodation of infiltration facilities, especially when encountered in a dense, compact state. Groundwater seepage was also encountered at relatively shallow depths. Please refer to Appendix C for the full study. 3. All target impervious surfaces not mitigated by Requirements 1 and 2 above, must be mitigated to the maximum extent feasible using one or more BMPs from the following list: • Full Infiltration: As noted above full infiltration is not feasible. • Limited Infiltration: Per the geotechnical engineering study, moderate to heavy ground water seepage was observed in the soil test pits at depths from 1’ to 3’ below existing grade. Given the presence of ground water seepage and Skattum Renton Plat Technical Information Report 9/30/2022 Page 21 vertical separation requirements, limited infiltration was determined to be infeasible. • Bioretention/Rain Gardens: Per the geotechnical engineering study, moderate to heavy ground water seepage was observed in the soil test pits at depths from 1’ to 3’ below existing grade. Given the presence of ground water seepage and vertical separation requirements, limited infiltration was determined to be infeasible. • Permeable Pavement: Per the geotechnical engineering study, moderate to heavy ground water seepage was observed in the soil test pits at depths from 1’ to 3’ below existing grade. Given the presence of ground water seepage and vertical separation requirements, limited infiltration was determined to be infeasible. 4. All target impervious surfaces not mitigated by Requirements 1, 2, and 3 above must be mitigated to the maximum extent feasible using Basic Dispersion. The feasibility of basic dispersion for each lot is described below: Lot 1: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. The proposed house is less than 25’ from the property line, given the required setbacks (10’ from structures and 5’ from property lines) and minimum trench length (10’), dispersion via a gravel filled trench is infeasible. The minimum 50’ flowpath for other dispersion techniques is not feasible. Therefore basic dispersion if not feasible for the roof area. Lot 2: Given the required setbacks, minimum flowpath lengths and proposed/existing grades, dispersion is infeasible for Lot 2. Lot 3: Given the existing/proposed grades, sheet flow dispersion is not feasible for the proposed driveway. Given the required setbacks and minimum flowpaths, dispersion is infeasible for the roof area. Lot 4: Given the existing/proposed grades, sheet flow dispersion is not feasible for the proposed driveway. Given the required setbacks and minimum flowpaths, dispersion is infeasible for the roof area. Lot 5: Given the existing/proposed grades and retained trees, dispersion is not feasible for the proposed driveway. The retained trees also make dispersion infeasible for the roof area as the dispersion trench would need to be located within the critical root zone of the retained trees. Lot 6: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. Given the proposed interceptor trench location, required setbacks, and required trench length, dispersion of the roof area for Lot 6 is infeasible. Skattum Renton Plat Technical Information Report 9/30/2022 Page 22 Lot 7: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. Basic dispersion via a gravel filled trench is proposed for the roof area. The trench was sized assuming a roof area of 1,500 SF. Per SWDM Section C.2.4.4,. 10 LF of trench is required per 700 SF of tributary impervious area. Therefore the proposed trench is 21.5 LF with a 25 flowpath ([1,500 SF / 700 SF] x 10 LF = 21.4 LF). Lot 8: Given the existing/proposed grades, sheet flow dispersion is not feasible for the proposed driveway. Basic dispersion via a gravel filled trench is proposed for the roof area. The trench was sized assuming a roof area of 1,500 SF. Per SWDM Section C.2.4.4,. 10 LF of trench is required per 700 SF of tributary impervious area. Therefore the proposed trench is 21.5 LF with a 25 flowpath ([1,500 SF / 700 SF] x 10 LF = 21.4 LF). Lot 9: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. Basic dispersion via a gravel filled trench is proposed for the roof area. The trench was sized assuming a roof area of 1,500 SF. Per SWDM Section C.2.4.4,. 10 LF of trench is required per 700 SF of tributary impervious area. Therefore the proposed trench is 21.5 LF with a 25 flowpath ([1,500 SF / 700 SF] x 10 LF = 21.4 LF). Lot 10: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. Basic dispersion via a gravel filled trench is proposed for the roof area. The trench was sized assuming a roof area of 1,500 SF. Per SWDM Section C.2.4.4,. 10 LF of trench is required per 700 SF of tributary impervious area. Therefore the proposed trench is 21.5 LF with a 25 flowpath ([1,500 SF / 700 SF] x 10 LF = 21.4 LF). Lot 11: Basic dispersion via sheet flow with a 10 LF flowpath will be implemented for the proposed driveway. Given the required setbacks and minimum flowpaths, dispersion is infeasible for the roof area. 5. BMPs must be implemented, at minimum, for an impervious area equal to at least 10% of the lot. If these minimum areas are not mitigated using feasible BMPs from Requirements 1, 2, 3, and 4 above, one or more BMPs from the following list are required to be implemented. • Reduced Impervious Surface Credit - Infeasible. The target impervious surface cannot be directed to vegetated pervious area or discharged through a perforated pipe connection. • Native Growth Retention Credit – Infeasible. The target impervious surface cannot be directed to vegetated pervious area or discharged through a perforated pipe connection. • Tree Retention Credit – Feasible. Tree numbers 101, 107, 108, 118, 119, 120, 121, and 124 will be retained, protected and are within 20’ of new/replaced Skattum Renton Plat Technical Information Report 9/30/2022 Page 23 impervious surface, therefore these trees meet the requirements for the tree credit BMP. The trees to be counted towards the credit are all evergreen, therefore 20% of their canopy (area within driplines) may be used for the credit. The total canopy area of these trees is 2,495 SF. See below for the calculation of the tree credit. Refer to the developed conditions exhibit on page 16 for the tree locations and canopies. Tree Retention Credit Calculation: 𝑆𝑟𝑑𝑑 𝐶𝑟𝑑𝑑𝑖𝑡= ∑𝐸𝑣𝑑𝑟𝑔𝑟𝑑𝑑𝑛 𝐶𝑎𝑛𝑛𝑛𝑥 𝐴𝑟𝑑𝑎 𝑥 0.20 𝑆𝑟𝑑𝑑 𝐶𝑟𝑑𝑑𝑖𝑡= 2,495 𝑆𝐸 𝑥 0.20 =499 𝑆𝐸 6. Soil amendment is required for all new pervious surfaces. A callout and soil amendment notes are provided on Sheet 3, Grading Plan. SECTION 5: Conveyance System Analysis and Design The on-site drainage conveyance system for the proposed development is planned to be constructed of a series of catch basins interconnected with 12” PVC pipe. The on-site drainage conveyance system for the bypassed offsite areas is planned to be constructed of 8” PVC. The conveyance calculations were performed using Manning’s Equation. The conveyance system was checked to ensure that during the 100-year storm event, the system would function adequately. The 100-year peak flows using WWHM 15-minute time steps from the developed site and the tributary area to the bypass system was compared to the maximum capacity of the pipes. Using the Manning’s Equation, the maximum capacity of a 12” PVC pipe sloped at 0.50% is 2.98 cfs, which is greater than the actual 100-year flow from the developed site of 1.27 cfs. Using Manning’s Equation, the maximum capacity of an 8” PVC pipe sloped at 2.0% is 2.02 cfs, which is greater than the 100-year flow from the offsite tributary area to the bypass system of 1.71 cfs. Since the 100-year flows are less than the maximum capacity of the proposed pipes, the system will have adequate capacity to convey the runoff. See below and the following page for the WWHM output and figure showing offsite tributary area. Please note that the offsite tributary impervious surfaces were estimated using King County iMap and aerial photographs. WWHM Output: Developed Site: Mitigated Landuse Totals for POC #1 Total Pervious Area:0.689 Total Impervious Area:1.412 ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.582552 5 year 0.753376 10 year 0.871564 Skattum Renton Plat Technical Information Report 9/30/2022 Page 24 25 year 1.027069 50 year 1.147585 100 year 1.272244 Offsite Area Tributary to Bypass System: Mitigated Landuse Totals for POC #1 Total Pervious Area:4.32 Total Impervious Area:0.37 ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.419044 5 year 0.68038 10 year 0.886023 25 year 1.183928 50 year 1.434246 100 year 1.709558 Figure 6: Offsite Area Tributary to Bypass System Skattum Renton Plat Technical Information Report 9/30/2022 Page 25 SITE Offsite Area Tributary to Bypass System Offsite Bypass Areas:AC Impervious = 0.37 Lawn = 3.36 Pasture* = 0.96 Total = 4.69 *The Marvin Gardens property was modeled as pasture since the site is mitigated with an onsite flow control facility. Marvin Gardens Property Skattum Renton Plat Technical Information Report 9/30/2022 Page 26 SECTION 6: Special Reports and Studies • Geotechnical Engineering Study; Earth Solutions NW; December 20, 2016 • Arborist Report; American Forest Management; December 13, 2016 • Wetland & Stream Reconnaissance; Altmann Oliver Associates; May 21, 2016 SECTION 7: Other Permits Single-Family Residential Building Permits and a Right-of-Way Use Permit from the City of Renton will be required. Utility permits to construct the water and sewer system will be required from Soos Creek Water and Sewer District. SECTION 8: CSWPP Analysis and Design Several standard Best Management Practices (BMP’s) will be utilized by the contractor to minimize the amount of erosion and sedimentation that may be perpetuated by the construction of the site. The thirteen erosion and sedimentation control measures are outlined below: Clearing Limits- Prior to any site clearing, the areas to remain undisturbed during the project construction shall be physically marked on the project site. The clearing limits are delineated on the TESC Plan as the area to be disturbed. Tree Protection fencing is proposed for the retained trees. Cover Measures- Temporary and permanent cover measures shall be provided when necessary to protect disturbed areas. Materials will be stockpiled on-site and will be covered with plastic sheeting per 2017 CORSWDM D.2.1.2.4 when necessary. Perimeter Protection- Silt fencing per 2017 CORSWDM D.2.1.3.1 shall be used downstream of all disturbed areas to filter sediment from sheet flow. Traffic Area Stabilization- The current entrances and parking areas shall be utilized for construction purposes. Sediment Retention- A sediment trap has been designed and located at the low point of the project site. In addition, a filter fence will be installed along the down gradient perimeter of the property. Catch basin filters will be installed in new and downstream catch basins. A note is provided on the TESC and SWPP Plan to maintain existing vegetation to the maximum extent possible. These safeguards are anticipated to provide sufficient control of sediment transport during construction. Surface Water Collection- Surface water will be collected in a series of interceptor ditches and routed to a sediment trap before discharge to the off-site system. Dewatering Control- Although dewatering is not anticipated, a note is provided on TESC/SWPP and Vault Detail Plan to alert the contractor that perched groundwater may be encountered (based on the site geotechnical report). Skattum Renton Plat Technical Information Report 9/30/2022 Page 27 Dust Control- Dust control will be implemented per 2017 CORSWDM Table D.2.1.8.A when necessary. Flow Control- A sediment trap has been designed to control sediment onsite during construction. When completed the detention/water quality vault will be used for temporary and long-term flow control. A full cleaning of the stormwater vault will be required prior to completion of the civil construction permit. Control Pollutants- No pollutants will be stored onsite, but a spill kit shall be retained onsite in case of any fuel spills from construction equipment. Protect Existing and Proposed Flow Control BMPs- Tree #101, 107, 108, 118, 119, 120, 121, & 124 shall be retained and protected throughout the construction of the project. Maintain BMPs- TESC/SWPP Plan BMPs shall be maintained and repaired as needed throughout construction. All disturbed areas of the project site shall be vegetated or otherwise permanently stabilized once completed. Manage the Project- The TESC plan shall be retained onsite or within reasonable access to the site. Prior to commencing construction, a contract for a CESCL will be established. SECTION 9: Bond Quantities, Facility Summaries, and Declaration of Covenant Bond Quantity Worksheet – Appendix F Declaration of Covenant for Privately Maintained Flow Control and Water Quality Features – Appendix G Flow Control and Water Quality Facility Summary Sheet and Sketch – Appendix H SECTION 10: Operations and Maintenance Manual A draft Operations & Maintenance Manual is provided in Appendix B. Skattum Renton Plat Technical Information Report APPENDIX A WWHM HYDROLOGIC ANALYSES WWHM2012 PROJECT REPORT Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 2 General Model Information Project Name:Skattum Renton Vault 9-1-20 Site Name:Skatum Renton Site Address: City: Report Date:11/11/2020 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.000 Version Date:2019/09/13 Version:4.2.17 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Mod 2.101 Pervious Total 2.101 Impervious Land Use acre Impervious Total 0 Basin Total 2.101 Element Flows To: Surface Interflow Groundwater Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.689 Pervious Total 0.689 Impervious Land Use acre ROADS FLAT 1.412 Impervious Total 1.412 Basin Total 2.101 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 5 Routing Elements Predeveloped Routing Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 6 Mitigated Routing Vault 1 Width:42.5 ft. Length:68.5 ft. Depth:11.75 ft. Discharge Structure Riser Height:10.75 ft. Riser Diameter:12 in. Notch Type:Rectangular Notch Width:0.003 ft. Notch Height:4.844 ft. Orifice 1 Diameter:0.6875 in.Elevation:0 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.066 0.000 0.000 0.000 0.1306 0.066 0.008 0.004 0.000 0.2611 0.066 0.017 0.006 0.000 0.3917 0.066 0.026 0.008 0.000 0.5222 0.066 0.034 0.009 0.000 0.6528 0.066 0.043 0.010 0.000 0.7833 0.066 0.052 0.011 0.000 0.9139 0.066 0.061 0.012 0.000 1.0444 0.066 0.069 0.013 0.000 1.1750 0.066 0.078 0.013 0.000 1.3056 0.066 0.087 0.014 0.000 1.4361 0.066 0.096 0.015 0.000 1.5667 0.066 0.104 0.016 0.000 1.6972 0.066 0.113 0.016 0.000 1.8278 0.066 0.122 0.017 0.000 1.9583 0.066 0.130 0.017 0.000 2.0889 0.066 0.139 0.018 0.000 2.2194 0.066 0.148 0.019 0.000 2.3500 0.066 0.157 0.019 0.000 2.4806 0.066 0.165 0.020 0.000 2.6111 0.066 0.174 0.020 0.000 2.7417 0.066 0.183 0.021 0.000 2.8722 0.066 0.192 0.021 0.000 3.0028 0.066 0.200 0.022 0.000 3.1333 0.066 0.209 0.022 0.000 3.2639 0.066 0.218 0.023 0.000 3.3944 0.066 0.226 0.023 0.000 3.5250 0.066 0.235 0.024 0.000 3.6556 0.066 0.244 0.024 0.000 3.7861 0.066 0.253 0.025 0.000 3.9167 0.066 0.261 0.025 0.000 4.0472 0.066 0.270 0.025 0.000 4.1778 0.066 0.279 0.026 0.000 4.3083 0.066 0.287 0.026 0.000 4.4389 0.066 0.296 0.027 0.000 4.5694 0.066 0.305 0.027 0.000 4.7000 0.066 0.314 0.027 0.000 Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 7 4.8306 0.066 0.322 0.028 0.000 4.9611 0.066 0.331 0.028 0.000 5.0917 0.066 0.340 0.028 0.000 5.2222 0.066 0.349 0.029 0.000 5.3528 0.066 0.357 0.029 0.000 5.4833 0.066 0.366 0.030 0.000 5.6139 0.066 0.375 0.030 0.000 5.7444 0.066 0.383 0.030 0.000 5.8750 0.066 0.392 0.031 0.000 6.0056 0.066 0.401 0.031 0.000 6.1361 0.066 0.410 0.032 0.000 6.2667 0.066 0.418 0.033 0.000 6.3972 0.066 0.427 0.035 0.000 6.5278 0.066 0.436 0.036 0.000 6.6583 0.066 0.445 0.037 0.000 6.7889 0.066 0.453 0.039 0.000 6.9194 0.066 0.462 0.040 0.000 7.0500 0.066 0.471 0.042 0.000 7.1806 0.066 0.479 0.044 0.000 7.3111 0.066 0.488 0.049 0.000 7.4417 0.066 0.497 0.052 0.000 7.5722 0.066 0.506 0.055 0.000 7.7028 0.066 0.514 0.057 0.000 7.8333 0.066 0.523 0.060 0.000 7.9639 0.066 0.532 0.063 0.000 8.0944 0.066 0.541 0.066 0.000 8.2250 0.066 0.549 0.069 0.000 8.3556 0.066 0.558 0.072 0.000 8.4861 0.066 0.567 0.075 0.000 8.6167 0.066 0.575 0.078 0.000 8.7472 0.066 0.584 0.081 0.000 8.8778 0.066 0.593 0.085 0.000 9.0083 0.066 0.602 0.088 0.000 9.1389 0.066 0.610 0.092 0.000 9.2694 0.066 0.619 0.095 0.000 9.4000 0.066 0.628 0.099 0.000 9.5306 0.066 0.637 0.102 0.000 9.6611 0.066 0.645 0.106 0.000 9.7917 0.066 0.654 0.110 0.000 9.9222 0.066 0.663 0.114 0.000 10.053 0.066 0.671 0.118 0.000 10.183 0.066 0.680 0.121 0.000 10.314 0.066 0.689 0.125 0.000 10.444 0.066 0.698 0.130 0.000 10.575 0.066 0.706 0.134 0.000 10.706 0.066 0.715 0.138 0.000 10.836 0.066 0.724 0.406 0.000 10.967 0.066 0.732 1.151 0.000 11.097 0.066 0.741 1.889 0.000 11.228 0.066 0.750 2.301 0.000 11.358 0.066 0.759 2.597 0.000 11.489 0.066 0.767 2.848 0.000 11.619 0.066 0.776 3.078 0.000 11.750 0.066 0.785 3.291 0.000 11.881 0.066 0.743 3.490 0.000 Skattum Renton Vault 9-1-20 11/11/2020 3:57:42 PM Page 8 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:2.101 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.689 Total Impervious Area:1.412 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.062558 5 year 0.102506 10 year 0.128193 25 year 0.158747 50 year 0.179912 100 year 0.19968 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.037463 5 year 0.058274 10 year 0.075576 25 year 0.102018 50 year 0.125429 100 year 0.152365 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.072 0.027 1950 0.085 0.035 1951 0.137 0.104 1952 0.043 0.024 1953 0.035 0.031 1954 0.053 0.029 1955 0.085 0.028 1956 0.068 0.057 1957 0.055 0.029 1958 0.061 0.032 Skattum Renton Vault 9-1-20 11/11/2020 3:58:12 PM Page 9 1959 0.053 0.027 1960 0.094 0.079 1961 0.052 0.040 1962 0.032 0.024 1963 0.044 0.030 1964 0.063 0.035 1965 0.042 0.051 1966 0.040 0.029 1967 0.096 0.034 1968 0.054 0.029 1969 0.053 0.029 1970 0.042 0.031 1971 0.048 0.031 1972 0.104 0.081 1973 0.046 0.050 1974 0.051 0.031 1975 0.071 0.028 1976 0.051 0.030 1977 0.007 0.025 1978 0.043 0.034 1979 0.026 0.023 1980 0.122 0.089 1981 0.038 0.030 1982 0.079 0.059 1983 0.068 0.031 1984 0.041 0.025 1985 0.024 0.026 1986 0.107 0.037 1987 0.095 0.068 1988 0.037 0.027 1989 0.025 0.026 1990 0.227 0.082 1991 0.120 0.071 1992 0.049 0.035 1993 0.048 0.025 1994 0.016 0.022 1995 0.069 0.039 1996 0.159 0.100 1997 0.122 0.105 1998 0.030 0.025 1999 0.134 0.077 2000 0.048 0.034 2001 0.009 0.020 2002 0.055 0.042 2003 0.083 0.029 2004 0.088 0.097 2005 0.065 0.029 2006 0.074 0.055 2007 0.171 0.137 2008 0.209 0.091 2009 0.097 0.045 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.2265 0.1371 2 0.2087 0.1055 3 0.1712 0.1042 Skattum Renton Vault 9-1-20 11/11/2020 3:58:12 PM Page 10 4 0.1586 0.1000 5 0.1367 0.0973 6 0.1342 0.0914 7 0.1224 0.0893 8 0.1222 0.0823 9 0.1202 0.0811 10 0.1072 0.0792 11 0.1038 0.0773 12 0.0973 0.0709 13 0.0961 0.0679 14 0.0946 0.0588 15 0.0943 0.0565 16 0.0882 0.0553 17 0.0855 0.0507 18 0.0850 0.0495 19 0.0826 0.0454 20 0.0792 0.0416 21 0.0736 0.0397 22 0.0720 0.0388 23 0.0710 0.0372 24 0.0686 0.0354 25 0.0685 0.0351 26 0.0678 0.0350 27 0.0655 0.0342 28 0.0628 0.0340 29 0.0614 0.0336 30 0.0553 0.0315 31 0.0553 0.0308 32 0.0541 0.0308 33 0.0532 0.0307 34 0.0527 0.0307 35 0.0526 0.0306 36 0.0519 0.0305 37 0.0510 0.0301 38 0.0507 0.0297 39 0.0491 0.0295 40 0.0479 0.0294 41 0.0477 0.0293 42 0.0477 0.0293 43 0.0460 0.0292 44 0.0443 0.0288 45 0.0429 0.0287 46 0.0428 0.0284 47 0.0422 0.0276 48 0.0418 0.0272 49 0.0408 0.0269 50 0.0401 0.0269 51 0.0383 0.0260 52 0.0374 0.0257 53 0.0347 0.0248 54 0.0323 0.0247 55 0.0300 0.0247 56 0.0259 0.0246 57 0.0247 0.0242 58 0.0242 0.0242 59 0.0161 0.0226 60 0.0086 0.0220 61 0.0074 0.0205 Skattum Renton Vault 9-1-20 11/11/2020 3:58:12 PM Page 11 Skattum Renton Vault 9-1-20 11/11/2020 3:58:12 PM Page 12 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0313 17085 14365 84 Pass 0.0328 15481 11766 76 Pass 0.0343 14067 10085 71 Pass 0.0358 12797 8898 69 Pass 0.0373 11567 7905 68 Pass 0.0388 10517 7001 66 Pass 0.0403 9563 6104 63 Pass 0.0418 8752 5309 60 Pass 0.0433 8038 4682 58 Pass 0.0448 7345 4141 56 Pass 0.0463 6733 3953 58 Pass 0.0478 6190 3811 61 Pass 0.0493 5726 3681 64 Pass 0.0508 5309 3450 64 Pass 0.0523 4924 3258 66 Pass 0.0538 4569 3080 67 Pass 0.0553 4235 2887 68 Pass 0.0568 3951 2725 68 Pass 0.0583 3643 2550 69 Pass 0.0598 3388 2331 68 Pass 0.0613 3133 2186 69 Pass 0.0628 2915 2055 70 Pass 0.0643 2706 1913 70 Pass 0.0658 2490 1765 70 Pass 0.0673 2314 1619 69 Pass 0.0688 2136 1487 69 Pass 0.0703 1972 1373 69 Pass 0.0718 1824 1281 70 Pass 0.0733 1702 1200 70 Pass 0.0748 1577 1101 69 Pass 0.0763 1443 1017 70 Pass 0.0778 1325 933 70 Pass 0.0793 1232 839 68 Pass 0.0808 1147 766 66 Pass 0.0823 1083 693 63 Pass 0.0838 1020 650 63 Pass 0.0853 947 601 63 Pass 0.0868 886 553 62 Pass 0.0883 823 468 56 Pass 0.0898 760 380 50 Pass 0.0913 725 325 44 Pass 0.0928 674 293 43 Pass 0.0943 623 264 42 Pass 0.0958 589 233 39 Pass 0.0973 549 202 36 Pass 0.0988 506 185 36 Pass 0.1003 469 163 34 Pass 0.1018 428 151 35 Pass 0.1033 388 139 35 Pass 0.1048 356 119 33 Pass 0.1063 328 112 34 Pass 0.1078 298 109 36 Pass 0.1093 270 106 39 Pass Skattum Renton Vault 9-1-20 11/11/2020 3:58:13 PM Page 13 0.1109 242 103 42 Pass 0.1124 219 93 42 Pass 0.1139 198 86 43 Pass 0.1154 176 81 46 Pass 0.1169 152 72 47 Pass 0.1184 130 65 50 Pass 0.1199 119 61 51 Pass 0.1214 104 57 54 Pass 0.1229 95 53 55 Pass 0.1244 84 49 58 Pass 0.1259 75 45 60 Pass 0.1274 69 42 60 Pass 0.1289 61 38 62 Pass 0.1304 54 36 66 Pass 0.1319 46 33 71 Pass 0.1334 39 28 71 Pass 0.1349 30 17 56 Pass 0.1364 25 9 36 Pass 0.1379 22 0 0 Pass 0.1394 20 0 0 Pass 0.1409 17 0 0 Pass 0.1424 14 0 0 Pass 0.1439 12 0 0 Pass 0.1454 9 0 0 Pass 0.1469 7 0 0 Pass 0.1484 7 0 0 Pass 0.1499 7 0 0 Pass 0.1514 6 0 0 Pass 0.1529 6 0 0 Pass 0.1544 6 0 0 Pass 0.1559 6 0 0 Pass 0.1574 6 0 0 Pass 0.1589 5 0 0 Pass 0.1604 5 0 0 Pass 0.1619 5 0 0 Pass 0.1634 5 0 0 Pass 0.1649 5 0 0 Pass 0.1664 5 0 0 Pass 0.1679 5 0 0 Pass 0.1694 4 0 0 Pass 0.1709 4 0 0 Pass 0.1724 3 0 0 Pass 0.1739 3 0 0 Pass 0.1754 3 0 0 Pass 0.1769 3 0 0 Pass 0.1784 3 0 0 Pass 0.1799 3 0 0 Pass Skattum Renton Vault 9-1-20 11/11/2020 3:58:13 PM Page 14 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.0574 acre-feet On-line facility target flow:0.029 cfs. Adjusted for 15 min:0.029 cfs. Off-line facility target flow:0.0191 cfs. Adjusted for 15 min:0.0191 cfs. Skattum Renton Vault 9-1-20 11/11/2020 3:58:13 PM Page 15 LID Report Skattum Renton Vault 9-1-20 11/11/2020 3:58:21 PM Page 16 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. Skattum Renton Vault 9-1-20 11/11/2020 3:58:21 PM Page 17 Appendix Predeveloped Schematic Skattum Renton Vault 9-1-20 11/11/2020 3:58:22 PM Page 18 Mitigated Schematic Skattum Renton Plat Technical Information Report APPENDIX B MAINTENANCE and OPERATIONS MANUAL Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report Skattum Renton Plat Technical Information Report APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-39 NO. 27 – GRAVEL FILLED DISPERSION TRENCH BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Blocking, obstructions Debris or trash limiting flow to dispersion trench or preventing spreader function. Dispersion trench able to receive full flow prior to and during wet season. Site Trash and debris Trash or debris that could end up in the dispersion trench is evident. No trash or debris that could get into the dispersion trench can be found. Pipes Plugged inlet The entrance to the pipe is restricted due to sediment, trash, or debris. The entrance to the pipe is not restricted. Vegetation/root growth in pipes Vegetation/roots that reduce free movement of water through pipes. Water flows freely through pipes. Plugged pipe Sediment or other material prevents free flow of water through the pipe. Water flows freely through pipes. Broken pipe or joint leaks. Damage to the pipe or pipe joints allowing water to seep out. Pipe does not allow water to exit other than at the outlet to the trench. Broken or missing cleanout caps Cleanout caps are broken, missing, or buried. Cleanout caps are accessible and intact. Structure Flow not reaching trench Flows are not getting into the trench as designed. Water enters and exits trench as designed. Perforated pipe plugged Flow not able to enter or properly exit from perforated pipe. Water freely enters and exits perforated pipe. Flow not spreading evenly at outlet of trench Outlet flows channelizing or not spreading evenly from trench. Sheet flow occurs at the outlet of the trench. Cleanout/inspection access does not allow cleaning or inspection of perforated pipe The cleanout/inspection access is not available. Cleanout/inspection access is available. Filter Media Plugged filter media Filter media plugged. Flow through filter media is normal. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-43 NO. 32 – RAINWATER HARVESTING BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Preventive Insufficient storage volume No rain water in storage unit at the beginning of the rain season. Maximum storage available at the beginning of the rain season (Oct. 1). Collection Area Trash and debris Trash of debris on collection area may plug filter system Collection area clear of trash and debris. Filter Restricted or plugged filter Filter is partially or fully plugged preventing water from getting in to the storage unit. Filter is allowing collection water into storage unit. NO. 33 – ROCK PAD BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on rock pad site. Rock pad site free of any trash or debris. Rock Pad Area Insufficient rock pad size Rock pad is not 2 feet by 3 feet by 6 inches thick or as designed. Rock pad is 2 feet by 3 feet by 6 inches thick or as designed. Vegetation growth Vegetation is seen growing in or through rock pad. No vegetation within rock pad area. Rock Exposed soil Soil can be seen through the rock pad. Full thickness of the rock pad is in place, no soil visible through rock pad. NO. 34 – SHEET FLOW BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the sheet flow site. Sheet flow site free of any trash or debris. Sheet flow area Erosion Soil erosion occurring in sheet flow zone. Soil erosion is not occurring and rills and channels have been repaired. Concentrated flow Sheet flow is not occurring in the sheet flow zone. Sheet flow area is regraded to provide sheet flow. NO. 35 – SPLASH BLOCK BMP MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on the splash block. Splash block site free of any trash or debris. Splash Block Dislodged splash block Splash block moved from outlet of downspout. Splash block correctly positioned to catch discharge from downspout. Channeling Water coming off the splash block causing erosion. No erosion occurs from the splash block. Downspout water misdirected Water coming from the downspout is not discharging to the dispersal area. Water is discharging normally to the dispersal area. Skattum Renton Plat Technical Information Report APPENDIX C GEOTECHNICAL REPORT EarthSolutionsNWLLC EarthSolutionsNWLLC Geotechnical Engineering Geology Environmental Scientists Construction Monitoring 1805 -136th Place N.E.,Suite 201 Bellevue,WA 98005 (425)449-4704 Fax (425)449-4711 www.earthsolutionsnw.com GEOTECHNICAL ENGINEERING STUDY PROPOSED RESIDENTIAL SHORT PLAT 17018 &17022 -106th AVENUE SOUTHEAST RENTON,WASHINGTON ES-4948 Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutionsNWLLC and Environmental Sciences Vicinity Map Skattum Short Plat Renton,Washington MRS BJP 12/19/2016 Dec.2016 4948 1 NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. Reference: King County,Washington Map 656 By The Thomas Guide Rand McNally 32nd Edition SITE Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutionsNWLLC and Environmental Sciences Test Pit Location Plan Skattum Short Plat Renton,Washington MRS BJP 12/19/2016 Dec.2016 4948 2 NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. 0 30 60 12 0 Scale in Feet1"=60' NORTHLEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-4948,Dec.2016 Subject Site Existing Building Proposed Building TP-1 Storm Drainage TP-1 TP-2 TP-3 TP-4TP-5 106TH AVENUE S.E.390 400 390 400 Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction MonitoringandEnvironmentalSciences EarthSolutionsNWLLC EarthSolutionsNWLLC RETAINING WALL DRAINAGE DETAIL Skattum Short Plat Renton,Washington MRS BJP 12/19/2016 Dec.2016 4948 3 NOTES: Free Draining Backfill should consist of soil having less than 5 percent fines. Percent passing #4 should be 25 to 75 percent. Sheet Drain may be feasible in lieu of Free Draining Backfill,per ESNW recommendations. Drain Pipe should consist of perforated, rigid PVC Pipe surrounded with 1" Drain Rock. LEGEND: Free Draining Structural Backfill 1 inch Drain Rock 18"Min. Structural Fill Perforated Drain Pipe (Surround In Drain Rock) SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Drwn. Checked Date Date Proj.No. Plate Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring and Environmental Sciences EarthSolutionsNWLLC EarthSolutionsNWLLC FOOTING DRAIN DETAIL Slope Perforated Rigid Drain Pipe (Surround with 1"Rock) 18"(Min.) NOTES: Do NOT tie roof downspouts to Footing Drain. Surface Seal to consist of 12"of less permeable,suitable soil.Slope away from building. LEGEND: Surface Seal;native soil or other low permeability material. 1"Drain Rock SCHEMATIC ONLY -NOT TO SCALE NOT A CONSTRUCTION DRAWING Skattum Short Plat Renton,Washington MRS BJP 12/19/2016 Dec.2016 4948 4 Skattum Renton Plat Technical Information Report APPENDIX D ARBORIST REPORT Arborist Report Skattum Plat 17018 & 17022 106th Ave SE Renton, WA December 13th, 2016 American Forest Management 12/13/2016 Table of Contents 1. Introduction .............................................................................................................. 1 2. Description ............................................................................................................... 1 3. Methodology ............................................................................................................ 1 4. Observations ........................................................................................................... 2 5. Discussion ............................................................................................................... 3 6. Tree Retention ......................................................................................................... 3 7. Tree Replacement .................................................................................................. .3 8. Tree Protection Measures…………………………………………………………………4 Appendix Site/Tree Photos – pages 7 - 12 Tree Summary Table – attached Tree Locator Map - attached Tree Plan Map – attached City of Renton Tree Protection Measures – page 6 Skattum Plat - Arborist Report Page 1 American Forest Management 12/13/2016 1. Introduction American Forest Management, Inc. was contacted by Keith Litchfield of Litchfield Engineering and was asked to compile an ‘Arborist Report’ for two parcels located within the City of Renton. The proposed subdivision encompasses the properties at 17018 & 17022 106th Ave SE. Our assignment is to prepare a written report on present tree conditions, which is to be filed with the preliminary permit application. This report encompasses all of the criteria set forth under City of Renton code section 4-4-130. The tree retention requirement is 30% of significant trees. Date of Field Examination: December 6th, 2016 2. Description 70 significant trees were identified and assessed on the property. According to City of Renton code, a significant tree is a tree with a caliper (trunk diameter measured 4-1/2’ above the ground) of at least 6” or an alder or cottonwood tree with a caliper of at least 8”. Trees planted within the most recent 10 years qualify as significant trees, regardless of the actual caliper. A numbered aluminum tag was placed on the lower trunks of the subject trees. These numbers were used for this assessment. Tree tag numbers correspond with the numbers on the Tree Summary Tables and copy of the attached site survey. There are eight neighboring trees with a drip lines that extend over the property line. 3. Methodology Each tree in this report was visited. Tree diameters were measured by tape. The tree heights were measured using a Spiegel Relaskop. Each tree was visually examined for defects and vigor. The tree assessment procedure involves the examination of many factors:  The crown of the tree is examined for current vigor. This is comprised of inspecting the crown (foliage, buds and branches) for color, density, form, and annual shoot growth, limb dieback and disease. The percentage of live crown is estimated for coniferous species only and scored appropriately.  The bole or main stem of the tree is inspected for decay, which includes cavities, wounds, fruiting bodies of decay (conks or mushrooms), seams, insects, bleeding, callus development, broken or dead tops, structural defects and unnatural leans. Structural defects include crooks, forks with V-shaped crotches, multiple attachments, and excessive sweep.  The root collar and roots are inspected for the presence of decay, insects and/or damage, as well as if they have been injured, undermined or exposed, or original grade has been altered. Based on these factors a determination of condition is made. The four condition categories are described below based on the species traits assessed: Excellent – free of structural defects, no disease or pest problems, no root issues, excellent structure/form with uniform crown or canopy, foliage of normal color and density, above average vigor, it will be wind firm if isolated, suitable for its location Good – free of significant structural defects, no disease concerns, minor pest issues, no significant root issues, good structure/form with uniform crown or canopy, foliage of normal color and density, average or normal vigor, will be wind firm if isolated or left as part of a grouping or grove of trees, suitable for its location Skattum Plat - Arborist Report Page 2 American Forest Management 12/13/2016 Fair – minor structural defects not expected to contribute to a failure in near future, no disease concerns, moderate pest issues, no significant root issues, asymmetric or unbalanced crown or canopy, average or normal vigor, foliage of normal color, moderate foliage density, will be wind firm if left as part of a grouping or grove of trees, cannot be isolated, suitable for its location Poor – major structural defects expected to fail in near future, disease or significant pest concerns, decline due to old age, significant root issues, asymmetric or unbalanced crown or canopy, sparse or abnormally small foliage, poor vigor, not suitable for its location A ‘viable’ tree is “A significant tree that a qualified professional has determined to be in good health, with a low risk of failure due to structural defects, is wind firm if isolated or remains as part of a grove, and is a species that is suitable for its location.” Trees considered ‘non-viable’ are trees that are in poor condition due to disease, age related decline, have significant decay issues and/or cumulative structural defects, which exacerbate failure potential. The attached tree map indicates the ‘condition’ of the subject trees found at the site. 4. Observations The subject trees are primarily native, mature conifers. Specific tree information for individual trees can be found on the attached tree table. The Douglas-fir trees on the property are generally healthy and mature, estimated at 60 – 70 years of age. Most were planted in rows or clusters. The row of Douglas-fir trees on the west property line, #150 - #156, are growing very closely together and should not be isolated. One incident of fungal disease was observed. A Phaeolus schweinitzii conk was found 1’ from the trunk of tree #132. The vigor of tree #132 is good and the infection is suspected to be incipient. Foliage color is good. All of the Douglas-fir trees on the site are viable. The western red cedar trees on the property are generally mature. Most of the western red cedar trees on the property are in groupings. Decay was observed in multiple trees. The decay is suspected to be brown cubical rot, but no fungal fruiting bodies were found. Some of the western red cedar trees were topped in the past. Co- dominant trunks with included bark were commonly observed and are the most concerning defect. The western red cedar trees on the property range in condition and all but one are viable. Tree #165 - #167 are black cottonwood trees on the west side of the property. Tree #165 and #166 are mature black cottonwoods growing closely together. Tree #165 has a DBH of 54” and a height of 167’. Tree #166 has a DBH of 45” and a height of 154’. Large limbs on both tree have failed but no other concerning defects were observed. Tree #167 is younger. The top of this tree broke off and there is decay in the trunk. All three trees are viable. Tree #149 is an English oak on the west property line. This tree has a forked trunk. The attachment between the two trunks is good. The crown is full and no other defects were observed. This tree is in good condition and is viable. Tree #125, #130 and #131 are European larch trees on the west side of the property. Tree #130 and #131 have poor trunk taper. All three trees are viable. Neighboring Trees Tree #201 - #206 are mature big leaf maple trees north and east of the property lines. Big leaf maple trees often have large lateral branches. Co-dominant trunks with included bark were the most common defects observed. All six trees are in fair to good condition and are viable. Tree #207 is a mature Douglas-fir south of the property line. This tree has no concerning defects, is in good condition and is viable. Skattum Plat - Arborist Report Page 3 American Forest Management 12/13/2016 5. Discussion The extent of drip-lines (farthest reaching branches) for the subject trees can be found on the tree summary tables at the back of this report. These have also been delineated on a copy of the site survey for viable/healthy trees proposed for retention. The information plotted on the attached survey plan may need to be transferred to a final tree retention/protection plan to meet City submittal requirements. The trees that are to be removed shall be shown “X’d” out on the final plan. The Limits of Disturbance (LOD) measurements can also be found on the tree summary table. This is the recommended distance of the closest impact (soil excavation) to the trunk face. These should be referenced when determining tree retention feasibility. The LOD measurements are based on species, age, condition, drip- line, prior improvements, proposed impacts and the anticipated cumulative impacts to the entire root zone. Tree Protection fencing shall be located beyond the drip-line edge of retained trees, and only moved back to the LOD when work is authorized. Trees on the property growing closely together are recommended for retention as groupings. One example is the row of Douglas-fir trees, #150 - #156 are growing in a row with only a few feet between each trunk. When trees are growing closely together, they often develop small trunk taper and live crown ratios. As long as the trees are retained as groupings and not isolated, the risk of failure is lessened. A Phaeolus schweinitzii conk was found 1’ from the trunk of tree #132. The vigor of tree #132 is good and the infection is suspected to be incipient. All conifers are susceptible to Phaeolus schweinitzii and it is likely present in multiple trees on the property. Trees in advanced stages of the disease often have thin crowns and/or branch dieback, and swollen lower trunks. No trees with advanced or significant internal decay were identified. The western red cedar trees on the property are mature and some concerning defects were observed. Brown cubical rot is suspected to be in multiple western red cedar trees on the property. The development of internal decay columns within mature cedar is common. As long as trees are vigorous and actively growing, the risk of failure remains low. Western red cedars are good at compartmentalizing decay radially and the presence of rot is not necessarily an indication that the tree is declining. The largest concern with the western red cedar trees on the site is co-dominant stems with included bark. Tree #115 is a western red cedar with co-dominant stems that have split apart. Failure of this tree is extremely likely. Tree #115 is a high risk tree and should be removed before work commences on the site. The tree density on the site is currently low and mainly concentrated in the southwest region of the property. Most of the trees are in the center and west side of the property. Sidewalk improvements, water utilites and the construction of new homes will prevent retention of the majority of the existing trees. The site will fall 8% short of meeting the required 30% significant tree retention requirement. New trees will be planted to mitigate for the tree removal and to enhance the landscape. There are no concerns with neighboring trees. The tree protection measures below will serve to protect these trees. 6. Tree Retention A total of 70 significant trees were identified on the subject property. One of the significant trees is in poor condition. This tree was not included in the tree calculation. Landmark trees and tree groves were prioritized when selecting trees for retention, per the City of Renton tree code 4-4-130. Tree Calculation based on 69, healthy, viable, significant trees Viable Trees proposed for removal – 54 (78%) Viable Trees proposed for retention – 15 (22%) Skattum Plat - Arborist Report Page 4 American Forest Management 12/13/2016 7. Tree Replacement Replacements trees may be required. Consult your city planner for tree replacement requirements. All replacement trees are to be planted on site. For planting and maintenance specifications, refer to Section 4-4- 130 of the Renton Tree Ordinances. 8. Tree Protection Measures The following guidelines are recommended to ensure that the designated space set aside for the preserved trees are protected and construction impacts are kept to a minimum. Refer to the City of Renton Code 4-4-130- 9. Protection Measures During Construction for more information.  Tree protection barriers shall be initially erected at 5’ outside of the drip-line prior to moving any heavy equipment on site.  Tree protection fencing shall only be moved where necessary to install improvements, but only as close as the Limits of Disturbance, as indicated on the attached plan.  Excavation limits should be laid out in paint on the ground to avoid over excavating.  Excavations within the drip-lines shall be monitored by a qualified tree professional so necessary precautions can be taken to decrease impacts to tree parts. A qualified tree professional shall monitor excavations when work is required and allowed up to the “Limits of Disturbance”.  To establish sub grade for foundations, curbs and pavement sections near the trees, soil should be removed parallel to the roots and not at 90 degree angles to avoid breaking and tearing roots that lead back to the trunk within the drip-line. Any roots damaged during these excavations should be exposed to sound tissue and cut cleanly with a saw. Cutting tools should be sterilized with alcohol.  Areas excavated within the drip-line of retained trees should be thoroughly irrigated weekly during dry periods.  Preparations for final landscaping shall be accomplished by hand within the drip-lines of retained trees. Plantings within the drip lines shall be limited. Large equipment shall be kept outside of the tree protection zones. Tree Type Removal Retained Total Landmark # 11 0 11 Landmark % 100% 0% 100% Significant # 43 15 58 Significant % 74% 26% 100% Total # 54 15 69 Total % 78% 22% 100% Skattum Plat - Arborist Report Page 5 American Forest Management 12/13/2016 There is no warranty suggested for any of the trees subject to this report. Weather, latent tree conditions, and future man-caused activities could cause physiologic changes and deteriorating tree condition. Over time, deteriorating tree conditions may appear and there may be conditions, which are not now visible which, could cause tree failure. This report or the verbal comments made at the site in no way warrant the structural stability or long term condition of any tree, but represent my opinion based on the observations made. Nearly all trees in any condition standing within reach of improvements or human use areas represent hazards that could lead to damage or injury. Please call if you have any questions or I can be of further assistance. Sincerely, Kelly Wilkinson kelly.wilkinson@afmforest.com ISA Certified Arborist #PN-7673A ISA Tree Risk Assessment Qualified Skattum Plat - Arborist Report Page 6 American Forest Management 12/13/2016 City of Renton Code 4-4-130- 9. Protection Measures During Construction a. Construction Storage Prohibited: The applicant may not fill, excavate, stack or store any equipment, dispose of any materials, supplies or fluids, operate any equipment, install impervious surfaces, or compact the earth in any way within the area defined by the drip line of any tree to be retained. b. Fenced Protection Area Required: Prior to development activities, the applicant shall erect and maintain six-foot (6') high chain link temporary construction fencing around the drip lines of all retained trees or at a distance surrounding the tree equal to one and one-quarter feet (1.25') for every one inch (1") of trunk caliper, whichever is greater, or along the perimeter of a tree protection tract. Placards shall be placed on fencing every fifty feet (50') indicating the words, “NO TRESPASSING – Protected Trees,” or on each side of the fencing if less than fifty feet (50'). Site access to individually protected trees or groups of trees shall be fenced and signed. Individual trees shall be fenced on four (4) sides. In addition, the applicant shall provide supervision whenever equipment or trucks are moving near trees. c. Protection from Grade Changes: If the grade level adjoining to a tree to be retained is to be raised, the applicant shall construct a dry rock wall or rock well around the tree. The diameter of this wall or well must be equal to the tree’s drip line. d. Impervious Surfaces Prohibited within the Drip Line: The applicant may not install impervious surface material within the area defined by the drip line of any tree to be retained. e. Restrictions on Grading within the Drip Lines of Retained Trees: The grade level around any tree to be retained may not be lowered within the greater of the following areas: (i) the area defined by the drip line of the tree, or (ii) an area around the tree equal to one and one-half feet (1-1/2') in diameter for each one inch (1") of tree caliper. A larger tree protection zone based on tree size, species, soil, or other conditions may be required. (Ord. 5676, 12-3-2012) f. Mulch Layer Required: All areas within the required fencing shall be covered completely and evenly with a minimum of three inches (3") of bark mulch prior to installation of the protective fencing. Exceptions may be approved if the mulch will adversely affect protected ground cover plants. (Ord. 5676, 12-3-2012) g. Monitoring Required during Construction: The applicant shall retain a certified arborist or licensed landscape architect to ensure trees are protected from development activities and/or to prune branches and roots, fertilize, and water as appropriate for any trees and ground cover that are to be retained. h. Alternative Protection: Alternative safeguards may be used if determined to provide equal or greater tree protection. (Ord. 5676, 12-3-2012) Skattum Plat - Arborist Report Page 7 American Forest Management 12/13/2016 Photos Northeast corner of the subject property Cluster of western red cedar trees (#106 - #108) Skattum Plat - Arborist Report Page 8 American Forest Management 12/13/2016 Tree #103 and #102 – big leaf maple and Douglas-fir trees Tree #114 – western red cedar with a self-corrected lean and column of trunk decay Skattum Plat - Arborist Report Page 9 American Forest Management 12/13/2016 Tree #113 – western red cedar with column of decay Grouping of western red cedar trees (#109 - #114) Skattum Plat - Arborist Report Page 10 American Forest Management 12/13/2016 Tree #115 – western red cedar with forked trunk and severe decay West side of subject property Skattum Plat - Arborist Report Page 11 American Forest Management 12/13/2016 Tree #132 – Douglas-fir tree with Phaeolus schweinitzii conk Tree #133 – European white birch with a large burl Skattum Plat - Arborist Report Page 12 American Forest Management 12/13/2016 East side of subject property, tree #169 in the center Tree #167 – black cottonwood with poor form Tree Summary Table American Forest Management, Inc. For:Skattum Plat Date:12/7/2016 City of Renton Inspector:Wilkinson Tree/DBH Height Tag #Species (inches)(feet)Condition Viability Comments Proposal N S E W 101 Douglas-fir 22 96 13 / 10 17 / 10 good viable retain 102 Douglas-fir 28 103 14 / 12 11 / 12 16 / 12 8 / 12 good viable Slight lean E retain 103 big leaf maple 29 85 12 / 12 21 / 12 19 / 12 18 / 12 good viable retain 104 Douglas-fir 12 42 9 / 6 14 / 6 17 / 6 fair viable retain 105 western red cedar 20 81 13 10 17 4 good viable remove 106 western red cedar 28 52 4 17 16 6 fair viable Topped remove 107 western red cedar 24 78 10 8 4 6 good viable remove 108 western red cedar 34 72 18 21 11 23 good viable landmark tree remove 109 western red cedar 37 45 10 17 15 10 good viable landmark tree remove 110 western red cedar 32 103 17 9 12 11 fair viable Top broke off, landmark tree remove 111 western red cedar 20 76 4 13 6 6 good viable remove 112 western red cedar 28, 24 (37)96 17 19 8 9 fair viable Forks at 2', landmark tree remove 113 western red cedar 25 77 18 6 5 17 fair viable Decay remove 114 western red cedar 32 68 2 17 7 14 fair viable decay, forked top, slight lean S, landmark tree remove 115 western red cedar 24 46 poor non-viable Trunk splitting, hazardous - non-significant remove 116 western red cedar 28 79 16 10 20 fair viable Connected at base to tree 115 remove 117 western red cedar 33 89 17 / 16 17 / 16 14 / 16 16 / 16 good viable Trunk forks at ~30', some included bark, landmark tree remove 118 Douglas-fir 27 109 8 / 13 10 / 13 12 / 13 9 / 13 good viable flat trunk on north side retain 119 Douglas-fir 26 120 4 / 12 15 / 12 9 / 12 4 / 12 good viable retain 120 Douglas-fir 21 91 12 / 10 9 / 10 16 / 10 good viable retain 121 Douglas-fir 16 81 5 / 8 9 / 8 12 / 8 6 / 8 fair viable retain 122 Douglas-fir 31 118 9 18 6 16 good viable landmark tree remove 123 Douglas-fir 28 111 13 8 9 11 good viable some old lower trunk bleeding remove 124 Douglas-fir 29 118 7 / 12 11 / 12 11 / 12 good viable retain 125 European larch 10 30 10 9 2 9 fair viable remove 126 Douglas-fir 38 110 20 25 24 18 good viable landmark tree remove 127 western red cedar 35 78 19 18 21 good viable landmark tree, in 106th Ave SE right-of-way remove 128 quaking aspen 11 55 9 6 5 11 good viable remove 129 quaking aspen 7 27 0 11 8 2 fair viable remove 130 European larch 14 76 10 6 7 9 fair viable poor trunk taper remove 131 European larch 15 74 6 8 6 11 fair viable poor trunk taper remove Drip-Line/Limits of Disturbance (feet) Tree Summary Table American Forest Management, Inc. For:Skattum Plat Date:12/7/2016 City of Renton Inspector:Wilkinson Tree/DBH Height Tag #Species (inches)(feet)Condition Viability Comments Proposal N S E W Drip-Line/Limits of Disturbance (feet) 132 Douglas-fir 20 74 10 13 6 15 fair viable Phaeolus schweinitzii conk found 1' from trunk on east side remove 133 European white birch 16 64 13 12 7 16 fair viable Burl on trunk remove 134 grand fir 28 77 12 16 14 15 good viable Forked top remove 135 western red cedar 26 84 15 12 19 12 fair viable Forked trunk, minor included bark remove 136 Douglas-fir 13 81 7 10 9 5 good viable remove 137 Douglas-fir 25 115 11 10 8 12 good viable remove 138 Douglas-fir 16 95 10 7 6 12 good viable remove 139 Douglas-fir 24 111 11 17 12 23 good viable remove 140 Douglas-fir 16 100 3 7 6 10 good viable remove 141 Douglas-fir 17 98 11 10 6 12 good viable remove 142 Douglas-fir 22 109 11 14 8 10 good viable remove 143 Douglas-fir 28 110 8 / 13 18 / 13 6 / 13 14 / 13 good viable remove 144 Douglas-fir 33 101 15 / 15 16 / 15 18 / 15 8 / 15 good viable landmark tree remove 145 western red cedar 22 83 6 / 12 12 / 12 16 / 12 5 / 12 good viable in grouping with tree #146 remove 146 western red cedar 27 85 8 / 14 11 / 14 9 / 14 11 / 14 good viable in grouping with tree #145 remove 147 Douglas-fir 29 118 15 8 11 13 good viable remove 148 Douglas-fir 19 100 7 7 9 14 good viable remove 149 English oak 25 91 4 19 11 17 good viable Forked trunk remove 150 Douglas-fir 17 45 13 11 17 good viable remove 151 Douglas-fir 20 95 10 11 good viable Slight lean N remove 152 Douglas-fir 19 91 16 15 good viable remove 153 Douglas-fir 11 63 11 8 good viable remove 154 Douglas-fir 18 85 12 14 good viable remove 155 Douglas-fir 19 83 6 14 good viable remove 156 Douglas-fir 12 52 8 7 7 good viable remove 157 western red cedar 23 38 15 12 11 good viable remove 158 western red cedar 13 23 10 9 9 good viable remove 159 western red cedar 18 39 14 / 15 7 / 15 12 / 15 fair viable Topped retain 160 western red cedar 14 45 13 / 12 9 / 12 7 / 12 fair viable Topped retain 161 western red cedar 19 55 12 / 10 9 / 10 10 / 10 good viable retain 162 western red cedar 23 61 12 / 16 10 / 16 6 / 16 good viable retain 163 Willow 6, 5, 4 (9)39 14 / 6 13 / 6 9 / 6 fair viable retain 164 Douglas-fir 12 51 14 / 6 15 / 6 good viable retain Tree Summary Table American Forest Management, Inc. For:Skattum Plat Date:12/7/2016 City of Renton Inspector:Wilkinson Tree/DBH Height Tag #Species (inches)(feet)Condition Viability Comments Proposal N S E W Drip-Line/Limits of Disturbance (feet) 165 black cottonwood 54 167 18 15 19 fair viable landmark tree remove 166 black cottonwood 45 154 18 17 11 fair viable Large limbs have failed, landmark tree remove 167 black cottonwood 12, 13 (17)55 17 19 16 17 fair viable decay, top broke off remove 168 western red cedar 23 54 16 13 14 14 good viable remove 169 Douglas-fir 23 94 10 17 15 15 good viable remove 170 western red cedar 25 85 8 9 11 11 good viable remove 201 big leaf maple 8, 7 (11)54 6 / 0 good viable Leans W, 10' east of property line protect 202 big leaf maple 16 71 6 / 2 fair viable protect 203 big leaf maple 18, 13, 15 (27)78 9 / 5 fair viable protect 204 big leaf maple 16, 18, 13 (27)70 12 / 14 fair viable 5' from property line protect 205 big leaf maple 29, 32 (43)111 5 / 14 16 / 14 19 / 14 good viable Trunk forks at base, good attachment, landmark tree protect 206 big leaf maple 28 73 18 / 12 good viable protect 207 Douglas-fir 28 94 10 / 2 good viable 8' S of property line protect 208 western red cedar 29, 16 (33)49 8 / 5 good viable 10' S of property line, landmark tree protect Drip-Line and Limits of Disturbance measurements from face of trunk Trees on neighboring properties - Drip-line and Limits of Disturbance measurements from property lines Calculated DBH: the DBH is parenthesis is the square root of the sum of the dbh for each individual stem squared (example with 3 stems: dbh = square root [(stem1)2 +(stem2)2 +(stem3)2]. Neighboring Trees Skattum Renton Plat Technical Information Report APPENDIX E WETLAND and STREAM RECONASSIANCE May 21, 2016 AOA-5175 Stein Skattum skattum@comcast.net SUBJECT: Wetland and Stream Reconnaissance for: 17018 and 17022 - 106th Ave. SE, Renton, WA Parcels 008700-0265 and -0270 Dear Stein: On May 19, 2016 I conducted a wetland and stream reconnaissance on the subject property utilizing the methodology outlined in the May 2010 Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0). No wetlands or streams are mapped on the City of Renton mapping and no wetlands or streams were identified on or adjacent to the property during the field investigation. Each of the two parcels are currently developed with a single-family residence and associated lawn and maintained yard areas. Scattered trees including Douglas fir (Pseudotsuga menziesii), big-leaf maple (Acer macrophyllum), western red cedar (Thuja plicata), and black cottonwood (Populus trichocarpa) were observed throughout both lots. An upland forested area is located off-site to the east. This off-site area was dominated by big-leaf maple, Indian plum (Oemleria cerasiformis), vine maple (Acer circinatum), bracken fern (Pteridium aquilinum), trailing blackberry (Rubus ursinus), and sword fern (Polystichum munitum). No hydrophytic plant communities were observed on or adjacent to the property. Borings taken throughout the two parcels revealed high chroma, dry, non-hydric, soils and there was no evidence of ponding or prolonged soil saturation anywhere on the property. Stein Skattum May 21, 2016 Page 2 Ditch During the field investigation, a small (~1-foot wide) ditch was observed along the east and south property lines of the site (Figure 1). Stormwater runoff from an off- site development to the northeast is collected in a vault and the overflow is discharged from a pipe at the NE corner of the 17018 residence. Intermittent runoff within the ditch then drains south and west before entering the roadside ditch adjacent the east side of 106th Ave. SE. A slight flow was observed discharging from the off-site vault at the time of the site visit. This runoff was observed infiltrating within the ditch near the southeast corner of the 17018 residence and the remainder of the ditch was dry. Since the ditch: 1) conveys entirely artificially collected stormwater runoff and 2) was cut through an upland where no stream previously existed, the ditch should not be considered a stream by the City of Renton or any other regulatory jurisdiction. Conclusion No wetlands or streams were identified on or immediately adjacent the site. This determination is based on a field investigation during which no hydrophytic plant communities, hydric soils, or evidence of wetland hydrology were observed. If you have any questions regarding the reconnaissance, please give me a call. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC John Altmann Ecologist King County, Pictometry International Corp., King County Figure 1 Date: 5/21/2016 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and is subject to changewithout notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness,or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liablefor any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profitsresulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map isprohibited except by written permission of King County. Approximate Ditch Stormwater Vault Outfall Culvert Skattum Renton Plat Technical Information Report APPENDIX F BOND QUANTITY WORKSHEET Planning Division |1055 South Grady Way – 6 th Floor | Renton, WA 98057 (425) 430-7200 Date Prepared: Name: PE Registration No: Firm Name: Firm Address: Phone No. Email Address: Project Name: Project Owner: CED Plan # (LUA):Phone: CED Permit # (U):Address: Site Address: Street Intersection:Addt'l Project Owner: Parcel #(s):Phone: Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NO Water Service Provided by: If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: SITE IMPROVEMENT BOND QUANTITY WORKSHEET PROJECT INFORMATION SOOS CREEK WATER & SEWER SOOS CREEK WATER & SEWER 1 Select the current project status/phase from the following options: For Approval - Preliminary Data Enclosed, pending approval from the City; For Construction - Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout - Final Costs and Quantities Enclosed for Project Close-out Submittal Engineer Stamp Required (all cost estimates must have original wet stamp and signature) Clearing and Grading Utility Providers N/A Project Location and Description Project Owner Information Renton Subdivision Renton, WA, 98057 008700-0265 & 008700-0270 Stein Skattum LUA16-000981 (206) 300-6231 9/30/2022 Prepared by: FOR APPROVALProject Phase 1 NicoleM@g2civil Nicole Mecum 39897 G2 Civil 1700 NW Gilman BLVD Suite 200 (425) 821-5038 17018 & 17022 106th Ave SE PO Box 769 Abbreviated Legal Description: TRACT 10, BLOCK 4 AKER'S FARMS NO. 5. & LOT 11, BLOCK 4, AKER'S FARMS NO. 5, ACCORDING TO THE PLAT THEREOF RECORDED IN VOLUME 40 OF PLATS, PAGE 27, RECORDS OF KING COUNTY, WASHINGTON. Page 2 of 14 Ref 8-H Bond Quantity Worksheet SECTION I PROJECT INFORMATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Unit Reference #Price Unit Quantity Cost Backfill & compaction-embankment ESC-1 6.50$ CY Check dams, 4" minus rock ESC-2 SWDM 5.4.6.3 80.00$ Each 5 400.00 Catch Basin Protection ESC-3 35.50$ Each Crushed surfacing 1 1/4" minus ESC-4 WSDOT 9-03.9(3)95.00$ CY Ditching ESC-5 9.00$ CY Excavation-bulk ESC-6 2.00$ CY Fence, silt ESC-7 SWDM 5.4.3.1 1.50$ LF 315 472.50 Fence, Temporary (NGPE)ESC-8 1.50$ LF Geotextile Fabric ESC-9 2.50$ SY Hay Bale Silt Trap ESC-10 0.50$ Each Hydroseeding ESC-11 SWDM 5.4.2.4 0.80$ SY 5000 4,000.00 Interceptor Swale / Dike ESC-12 1.00$ LF 405 405.00 Jute Mesh ESC-13 SWDM 5.4.2.2 3.50$ SY Level Spreader ESC-14 1.75$ LF Mulch, by hand, straw, 3" deep ESC-15 SWDM 5.4.2.1 2.50$ SY Mulch, by machine, straw, 2" deep ESC-16 SWDM 5.4.2.1 2.00$ SY Piping, temporary, CPP, 6"ESC-17 12.00$ LF Piping, temporary, CPP, 8"ESC-18 14.00$ LF 25 350.00 Piping, temporary, CPP, 12"ESC-19 18.00$ LF Plastic covering, 6mm thick, sandbagged ESC-20 SWDM 5.4.2.3 4.00$ SY 60 240.00 Rip Rap, machine placed; slopes ESC-21 WSDOT 9-13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22 SWDM 5.4.4.1 1,800.00$ Each 1 1,800.00 Rock Construction Entrance, 100'x15'x1'ESC-23 SWDM 5.4.4.1 3,200.00$ Each Sediment pond riser assembly ESC-24 SWDM 5.4.5.2 2,200.00$ Each Sediment trap, 5' high berm ESC-25 SWDM 5.4.5.1 19.00$ LF 45 855.00 Sed. trap, 5' high, riprapped spillway berm section ESC-26 SWDM 5.4.5.1 70.00$ LF 3 210.00 Seeding, by hand ESC-27 SWDM 5.4.2.4 1.00$ SY Sodding, 1" deep, level ground ESC-28 SWDM 5.4.2.5 8.00$ SY Sodding, 1" deep, sloped ground ESC-29 SWDM 5.4.2.5 10.00$ SY TESC Supervisor ESC-30 110.00$ HR Water truck, dust control ESC-31 SWDM 5.4.7 140.00$ HR Unit Reference #Price Unit Quantity Cost EROSION/SEDIMENT SUBTOTAL:8,732.50 SALES TAX @ 10%873.25 EROSION/SEDIMENT TOTAL:9,605.75 (A) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR EROSION & SEDIMENT CONTROL Description No. (A) WRITE-IN-ITEMS Page 3 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.a EROSION_CONTROL Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost GENERAL ITEMS Backfill & Compaction- embankment GI-1 6.00$ CY Backfill & Compaction- trench GI-2 9.00$ CY Clear/Remove Brush, by hand (SY)GI-3 1.00$ SY Bollards - fixed GI-4 240.74$ Each Bollards - removable GI-5 452.34$ Each 4 1,809.36 Clearing/Grubbing/Tree Removal GI-6 10,000.00$ Acre 0.5 5,000.00 1.6 16,000.00 Excavation - bulk GI-7 2.00$ CY 10 20.00 2000 4,000.00 Excavation - Trench GI-8 5.00$ CY Fencing, cedar, 6' high GI-9 20.00$ LF Fencing, chain link, 4'GI-10 38.31$ LF Fencing, chain link, vinyl coated, 6' high GI-11 20.00$ LF Fencing, chain link, gate, vinyl coated, 20' GI-12 1,400.00$ Each Fill & compact - common barrow GI-13 25.00$ CY Fill & compact - gravel base GI-14 27.00$ CY Fill & compact - screened topsoil GI-15 39.00$ CY Gabion, 12" deep, stone filled mesh GI-16 65.00$ SY Gabion, 18" deep, stone filled mesh GI-17 90.00$ SY Gabion, 36" deep, stone filled mesh GI-18 150.00$ SY Grading, fine, by hand GI-19 2.50$ SY Grading, fine, with grader GI-20 2.00$ SY Monuments, 3' Long GI-21 250.00$ Each Sensitive Areas Sign GI-22 7.00$ Each Sodding, 1" deep, sloped ground GI-23 8.00$ SY Surveying, line & grade GI-24 850.00$ Day 1 850.00 5 4,250.00 Surveying, lot location/lines GI-25 1,800.00$ Acre 1 1,800.00 Topsoil Type A (imported)GI-26 28.50$ CY Traffic control crew ( 2 flaggers )GI-27 120.00$ HR 48 5,760.00 Trail, 4" chipped wood GI-28 8.00$ SY Trail, 4" crushed cinder GI-29 9.00$ SY Trail, 4" top course GI-30 12.00$ SY Conduit, 2"GI-31 5.00$ LF Wall, retaining, concrete GI-32 55.00$ SF Wall, rockery GI-33 15.00$ SF SUBTOTAL THIS PAGE:13,439.36 26,050.00 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) Page 4 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) ROAD IMPROVEMENT/PAVEMENT/SURFACING AC Grinding, 4' wide machine < 1000sy RI-1 30.00$ SY AC Grinding, 4' wide machine 1000-2000sy RI-2 16.00$ SY AC Grinding, 4' wide machine > 2000sy RI-3 10.00$ SY AC Removal/Disposal RI-4 35.00$ SY Barricade, Type III ( Permanent )RI-5 56.00$ LF Guard Rail RI-6 30.00$ LF Curb & Gutter, rolled RI-7 17.00$ LF Curb & Gutter, vertical RI-8 12.50$ LF 845 10,562.50 Curb and Gutter, demolition and disposal RI-9 18.00$ LF Curb, extruded asphalt RI-10 5.50$ LF Curb, extruded concrete RI-11 7.00$ LF Sawcut, asphalt, 3" depth RI-12 1.85$ LF 1274 2,356.90 Sawcut, concrete, per 1" depth RI-13 3.00$ LF Sealant, asphalt RI-14 2.00$ LF 1274 2,548.00 Shoulder, gravel, 4" thick RI-15 15.00$ SY Sidewalk, 4" thick RI-16 38.00$ SY 450 17,100.00 Sidewalk, 4" thick, demolition and disposal RI-17 32.00$ SY Sidewalk, 5" thick RI-18 41.00$ SY Sidewalk, 5" thick, demolition and disposal RI-19 40.00$ SY Sign, Handicap RI-20 85.00$ Each Striping, per stall RI-21 7.00$ Each Striping, thermoplastic, ( for crosswalk )RI-22 3.00$ SF Striping, 4" reflectorized line RI-23 0.50$ LF Additional 2.5" Crushed Surfacing RI-24 3.60$ SY HMA 1/2" Overlay 1.5" RI-25 14.00$ SY HMA 1/2" Overlay 2"RI-26 18.00$ SY HMA Road, 2", 4" rock, First 2500 SY RI-27 28.00$ SY HMA Road, 2", 4" rock, Qty. over 2500SY RI-28 21.00$ SY HMA Road, 4", 6" rock, First 2500 SY RI-29 45.00$ SY 651 29,295.00 726 32,670.00 HMA Road, 4", 6" rock, Qty. over 2500 SY RI-30 37.00$ SY HMA Road, 4", 4.5" ATB RI-31 38.00$ SY Gravel Road, 4" rock, First 2500 SY RI-32 15.00$ SY Gravel Road, 4" rock, Qty. over 2500 SY RI-33 10.00$ SY Thickened Edge RI-34 8.60$ LF 37 318.20 SUBTOTAL THIS PAGE:61,862.40 32,670.00 318.20 (B)(C)(D)(E) Page 5 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) PARKING LOT SURFACING No. 2" AC, 2" top course rock & 4" borrow PL-1 21.00$ SY 2" AC, 1.5" top course & 2.5" base course PL-2 28.00$ SY 4" select borrow PL-3 5.00$ SY 1.5" top course rock & 2.5" base course PL-4 14.00$ SY SUBTOTAL PARKING LOT SURFACING: (B)(C)(D)(E) LANDSCAPING & VEGETATION No. Street Trees LA-1 350.00$ EACH 18 6,300.00 Median Landscaping LA-2 Right-of-Way Landscaping LA-3 Wetland Landscaping LA-4 SUBTOTAL LANDSCAPING & VEGETATION:6,300.00 (B)(C)(D)(E) TRAFFIC & LIGHTING No. Signs TR-1 450.00$ EA 1 450.00 Street Light System ( # of Poles)TR-2 2,000.00$ EA 3 6,000.00 6 12,000.00 Traffic Signal TR-3 Traffic Signal Modification TR-4 SUBTOTAL TRAFFIC & LIGHTING:6,000.00 12,450.00 (B)(C)(D)(E) WRITE-IN-ITEMS SUBTOTAL WRITE-IN ITEMS: STREET AND SITE IMPROVEMENTS SUBTOTAL:87,601.76 45,120.00 26,368.20 SALES TAX @ 10%8,760.18 4,512.00 2,636.82 STREET AND SITE IMPROVEMENTS TOTAL:96,361.94 49,632.00 29,005.02 (B)(C)(D)(E) Page 6 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost DRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D-1 26.00$ SY * (CBs include frame and lid) Beehive D-2 90.00$ Each Through-curb Inlet Framework D-3 400.00$ Each 3 1,200.00 CB Type I D-4 1,500.00$ Each 3 4,500.00 8 12,000.00 7 10,500.00 CB Type IL D-5 1,750.00$ Each CB Type II, 48" diameter D-6 2,300.00$ Each 2 4,600.00 2 4,600.00 2 4,600.00 for additional depth over 4' D-7 480.00$ FT CB Type II, 54" diameter D-8 2,500.00$ Each for additional depth over 4'D-9 495.00$ FT CB Type II, 60" diameter D-10 2,800.00$ Each for additional depth over 4'D-11 600.00$ FT CB Type II, 72" diameter D-12 6,000.00$ Each for additional depth over 4'D-13 850.00$ FT CB Type II, 96" diameter D-14 14,000.00$ Each for additional depth over 4'D-15 925.00$ FT Trash Rack, 12"D-16 350.00$ Each Trash Rack, 15"D-17 410.00$ Each Trash Rack, 18"D-18 480.00$ Each Trash Rack, 21"D-19 550.00$ Each Cleanout, PVC, 4"D-20 150.00$ Each Cleanout, PVC, 6"D-21 170.00$ Each 12 2,040.00 Cleanout, PVC, 8"D-22 200.00$ Each Culvert, PVC, 4" D-23 10.00$ LF Culvert, PVC, 6" D-24 13.00$ LF Culvert, PVC, 8" D-25 15.00$ LF Culvert, PVC, 12" D-26 23.00$ LF Culvert, PVC, 15" D-27 35.00$ LF Culvert, PVC, 18" D-28 41.00$ LF Culvert, PVC, 24"D-29 56.00$ LF Culvert, PVC, 30" D-30 78.00$ LF Culvert, PVC, 36" D-31 130.00$ LF Culvert, CMP, 8"D-32 19.00$ LF Culvert, CMP, 12"D-33 29.00$ LF SUBTOTAL THIS PAGE:9,100.00 17,800.00 17,140.00 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) Page 7 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) DRAINAGE (Continued) Culvert, CMP, 15"D-34 35.00$ LF Culvert, CMP, 18"D-35 41.00$ LF Culvert, CMP, 24"D-36 56.00$ LF Culvert, CMP, 30"D-37 78.00$ LF Culvert, CMP, 36"D-38 130.00$ LF Culvert, CMP, 48"D-39 190.00$ LF Culvert, CMP, 60"D-40 270.00$ LF Culvert, CMP, 72"D-41 350.00$ LF Culvert, Concrete, 8"D-42 42.00$ LF Culvert, Concrete, 12"D-43 48.00$ LF Culvert, Concrete, 15"D-44 78.00$ LF Culvert, Concrete, 18"D-45 48.00$ LF Culvert, Concrete, 24"D-46 78.00$ LF Culvert, Concrete, 30"D-47 125.00$ LF Culvert, Concrete, 36"D-48 150.00$ LF Culvert, Concrete, 42"D-49 175.00$ LF Culvert, Concrete, 48"D-50 205.00$ LF Culvert, CPE Triple Wall, 6" D-51 14.00$ LF Culvert, CPE Triple Wall, 8" D-52 16.00$ LF Culvert, CPE Triple Wall, 12" D-53 24.00$ LF Culvert, CPE Triple Wall, 15" D-54 35.00$ LF Culvert, CPE Triple Wall, 18" D-55 41.00$ LF Culvert, CPE Triple Wall, 24" D-56 56.00$ LF Culvert, CPE Triple Wall, 30" D-57 78.00$ LF Culvert, CPE Triple Wall, 36" D-58 130.00$ LF Culvert, LCPE, 6"D-59 60.00$ LF Culvert, LCPE, 8"D-60 72.00$ LF 563 40,536.00 Culvert, LCPE, 12"D-61 84.00$ LF 610 51,240.00 343 28,812.00 Culvert, LCPE, 15"D-62 96.00$ LF Culvert, LCPE, 18"D-63 108.00$ LF Culvert, LCPE, 24"D-64 120.00$ LF Culvert, LCPE, 30"D-65 132.00$ LF Culvert, LCPE, 36"D-66 144.00$ LF Culvert, LCPE, 48"D-67 156.00$ LF Culvert, LCPE, 54"D-68 168.00$ LF SUBTOTAL THIS PAGE:51,240.00 28,812.00 40,536.00 (B)(C)(D)(E) Page 8 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) DRAINAGE (Continued) Culvert, LCPE, 60"D-69 180.00$ LF Culvert, LCPE, 72"D-70 192.00$ LF Culvert, HDPE, 6"D-71 42.00$ LF Culvert, HDPE, 8"D-72 42.00$ LF Culvert, HDPE, 12"D-73 74.00$ LF Culvert, HDPE, 15"D-74 106.00$ LF Culvert, HDPE, 18"D-75 138.00$ LF Culvert, HDPE, 24"D-76 221.00$ LF Culvert, HDPE, 30"D-77 276.00$ LF Culvert, HDPE, 36"D-78 331.00$ LF Culvert, HDPE, 48"D-79 386.00$ LF Culvert, HDPE, 54"D-80 441.00$ LF Culvert, HDPE, 60"D-81 496.00$ LF Culvert, HDPE, 72"D-82 551.00$ LF Pipe, Polypropylene, 6"D-83 84.00$ LF Pipe, Polypropylene, 8"D-84 89.00$ LF Pipe, Polypropylene, 12"D-85 95.00$ LF Pipe, Polypropylene, 15"D-86 100.00$ LF Pipe, Polypropylene, 18"D-87 106.00$ LF Pipe, Polypropylene, 24"D-88 111.00$ LF Pipe, Polypropylene, 30"D-89 119.00$ LF Pipe, Polypropylene, 36"D-90 154.00$ LF Pipe, Polypropylene, 48"D-91 226.00$ LF Pipe, Polypropylene, 54"D-92 332.00$ LF Pipe, Polypropylene, 60"D-93 439.00$ LF Pipe, Polypropylene, 72"D-94 545.00$ LF Culvert, DI, 6"D-95 61.00$ LF Culvert, DI, 8"D-96 84.00$ LF Culvert, DI, 12"D-97 106.00$ LF Culvert, DI, 15"D-98 129.00$ LF Culvert, DI, 18"D-99 152.00$ LF Culvert, DI, 24"D-100 175.00$ LF Culvert, DI, 30"D-101 198.00$ LF Culvert, DI, 36"D-102 220.00$ LF Culvert, DI, 48"D-103 243.00$ LF Culvert, DI, 54"D-104 266.00$ LF Culvert, DI, 60"D-105 289.00$ LF Culvert, DI, 72"D-106 311.00$ LF SUBTOTAL THIS PAGE: (B)(C)(D)(E) Page 9 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) Specialty Drainage Items Ditching SD-1 9.50$ CY Flow Dispersal Trench (1,436 base+)SD-3 28.00$ LF French Drain (3' depth)SD-4 26.00$ LF Geotextile, laid in trench, polypropylene SD-5 3.00$ SY Mid-tank Access Riser, 48" dia, 6' deep SD-6 2,000.00$ Each Pond Overflow Spillway SD-7 16.00$ SY Restrictor/Oil Separator, 12"SD-8 1,150.00$ Each 1 1,150.00 Restrictor/Oil Separator, 15"SD-9 1,350.00$ Each Restrictor/Oil Separator, 18"SD-10 1,700.00$ Each Riprap, placed SD-11 42.00$ CY 5 210.00 Tank End Reducer (36" diameter)SD-12 1,200.00$ Each Infiltration pond testing SD-13 125.00$ HR Permeable Pavement SD-14 Permeable Concrete Sidewalk SD-15 Culvert, Box __ ft x __ ft SD-16 SUBTOTAL SPECIALTY DRAINAGE ITEMS:1,150.00 210.00 (B)(C)(D)(E) STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch) Detention Pond SF-1 Each Detention Tank SF-2 Each Detention Vault SF-3 Each Infiltration Pond SF-4 Each Infiltration Tank SF-5 Each Infiltration Vault SF-6 Each Infiltration Trenches SF-7 Each Basic Biofiltration Swale SF-8 Each Wet Biofiltration Swale SF-9 Each Wetpond SF-10 Each Wetvault SF-11 Each Sand Filter SF-12 Each Sand Filter Vault SF-13 Each Linear Sand Filter SF-14 Each Proprietary Facility SF-15 Each Bioretention Facility SF-16 Each SUBTOTAL STORMWATER FACILITIES: (B)(C)(D)(E) Page 10 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) WRITE-IN-ITEMS (INCLUDE ON-SITE BMPs) Combined Detention/Wetvault WI-1 85,000.00$ LS 1 85,000.00 WI-2 WI-3 WI-4 WI-5 WI-6 WI-7 WI-8 WI-9 WI-10 WI-11 WI-12 WI-13 WI-14 WI-15 SUBTOTAL WRITE-IN ITEMS:85,000.00 DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:60,340.00 132,762.00 57,886.00 SALES TAX @ 10%6,034.00 13,276.20 5,788.60 DRAINAGE AND STORMWATER FACILITIES TOTAL:66,374.00 146,038.20 63,674.60 (B) (C) (D) (E) Page 11 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Connection to Existing Watermain W-1 2,000.00$ Each Ductile Iron Watermain, CL 52, 4 Inch Diameter W-2 50.00$ LF Ductile Iron Watermain, CL 52, 6 Inch Diameter W-3 56.00$ LF Ductile Iron Watermain, CL 52, 8 Inch Diameter W-4 60.00$ LF Ductile Iron Watermain, CL 52, 10 Inch Diameter W-5 70.00$ LF Ductile Iron Watermain, CL 52, 12 Inch Diameter W-6 80.00$ LF Gate Valve, 4 inch Diameter W-7 500.00$ Each Gate Valve, 6 inch Diameter W-8 700.00$ Each Gate Valve, 8 Inch Diameter W-9 800.00$ Each Gate Valve, 10 Inch Diameter W-10 1,000.00$ Each Gate Valve, 12 Inch Diameter W-11 1,200.00$ Each Fire Hydrant Assembly W-12 4,000.00$ Each Permanent Blow-Off Assembly W-13 1,800.00$ Each Air-Vac Assembly, 2-Inch Diameter W-14 2,000.00$ Each Air-Vac Assembly, 1-Inch Diameter W-15 1,500.00$ Each Compound Meter Assembly 3-inch Diameter W-16 8,000.00$ Each Compound Meter Assembly 4-inch Diameter W-17 9,000.00$ Each Compound Meter Assembly 6-inch Diameter W-18 10,000.00$ Each Pressure Reducing Valve Station 8-inch to 10-inch W-19 20,000.00$ Each WATER SUBTOTAL: SALES TAX @ 10% WATER TOTAL: (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR WATER Quantity Remaining (Bond Reduction) (B)(C) Page 12 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.d WATER Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 CED Permit #: Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost Clean Outs SS-1 1,000.00$ Each Grease Interceptor, 500 gallon SS-2 8,000.00$ Each Grease Interceptor, 1000 gallon SS-3 10,000.00$ Each Grease Interceptor, 1500 gallon SS-4 15,000.00$ Each Side Sewer Pipe, PVC. 4 Inch Diameter SS-5 80.00$ LF Side Sewer Pipe, PVC. 6 Inch Diameter SS-6 95.00$ LF Sewer Pipe, PVC, 8 inch Diameter SS-7 105.00$ LF Sewer Pipe, PVC, 12 Inch Diameter SS-8 120.00$ LF Sewer Pipe, DI, 8 inch Diameter SS-9 115.00$ LF Sewer Pipe, DI, 12 Inch Diameter SS-10 130.00$ LF Manhole, 48 Inch Diameter SS-11 6,000.00$ Each Manhole, 54 Inch Diameter SS-13 6,500.00$ Each Manhole, 60 Inch Diameter SS-15 7,500.00$ Each Manhole, 72 Inch Diameter SS-17 8,500.00$ Each Manhole, 96 Inch Diameter SS-19 14,000.00$ Each Pipe, C-900, 12 Inch Diameter SS-21 180.00$ LF Outside Drop SS-24 1,500.00$ LS Inside Drop SS-25 1,000.00$ LS Sewer Pipe, PVC, ____ Inch Diameter SS-26 Lift Station (Entire System)SS-27 LS SANITARY SEWER SUBTOTAL: SALES TAX @ 10% SANITARY SEWER TOTAL: (B) (C) (D) (E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR SANITARY SEWER Quantity Remaining (Bond Reduction) (B)(C) Page 13 of 14 Ref 8-H Bond Quantity Worksheet SECTION II.e SANITARY SEWER Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200 Date: Name:Project Name: PE Registration No:CED Plan # (LUA): Firm Name:CED Permit # (U): Firm Address:Site Address: Phone No.Parcel #(s): Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a) Existing Right-of-Way Improvements Subtotal (b)(b)96,361.94$ Future Public Improvements Subtotal (c)49,632.00$ Stormwater & Drainage Facilities (Public & Private) Subtotal (d)(d)276,086.80$ (e) (f) Site Restoration Civil Construction Permit Maintenance Bond 84,416.15$ Bond Reduction 2 Construction Permit Bond Amount 3 Minimum Bond Amount is $10,000.00 1 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering. 2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% will cover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering. * Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton. ** Note: All prices include labor, equipment, materials, overhead and profit. (425) 821-5038 NicoleM@g2civil Renton Subdivision LUA16-000981 17018 & 17022 106th Ave SE 008700-0265 & 008700-0270 FOR APPROVAL 1700 NW Gilman BLVD Suite 200 430,235.45$ P (a) x 100% SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS 9/30/2022 Nicole Mecum 39897 G2 Civil R ((b x 150%) + (d x 100%)) S (e) x 150% + (f) x 100% Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2 Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2 T (P +R - S) Prepared by:Project Information CONSTRUCTION BOND AMOUNT */** (prior to permit issuance) EST1 ((b) + (c) + (d)) x 20% -$ MAINTENANCE BOND */** (after final acceptance of construction) 9,605.75$ 96,361.94$ 420,629.70$ 9,605.75$ -$ 276,086.80$ -$ Page 14 of 14 Ref 8-H Bond Quantity Worksheet SECTION III. BOND WORKSHEET Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 9/30/2022 Skattum Renton Plat Technical Information Report APPENDIX G DECLARATION OF COVENANT Page 1 of ___ Return Address: City Clerk’s Office City of Renton 1055 S Grady Way Renton, WA 98057 DECLARATION OF COVENANT FOR INSPECTION AND MAINTENANCE OF DRAINAGE FACILITIES AND ON-SITE BMPS Grantor: Grantee: City of Renton, a Washington municipal corporation Legal Description: Assessor's Tax Parcel ID#: IN CONSIDERATION of the approved City of Renton (check one of the following) Residential Building Permit Commercial Building Permit Clearing and Grading Permit Civil Construction or Utility Permit for Permit(s)_____________________ (Construction/Building/Utility Permit #) relating to the real property ("Property") described above, the Grantor(s), the owner(s) in fee of that Property, hereby covenants (covenant) with the City of Renton (“City of Renton” or “City”), a municipal corporation of the state of Washington, that he/she (they) will observe, consent to, and abide by the conditions and obligations set forth and described in Paragraphs 1 through 9 below with regard to the Property, and hereby grants (grant) an easement as described in Paragraphs 2 and 3. Grantor(s) hereby grants (grant), covenants (covenant), and agrees (agree) as follows: 1.The Grantor(s) or his/her (their) successors in interest and assigns ("Owners ") shall at their own cost, operate, maintain, and keep in good repair, the Property's drainage facilities constructed as required in the approved construction plans and specifications __________________ (Project Plan #) on file with the City of Renton and submitted to the City of Renton for the review and approval of permit(s) _____________________________ (Construction/Building/Utility Permit #). The Property's drainage facilities are shown and/or listed on Exhibit A – Site Plan. The Property’s drainage facilities shall be maintained in compliance with the operation and maintenance schedule included and attached herein as Exhibit B – Operations and Maintenance. Drainage facilities include pipes, channels, flow control facilities, water quality facilities, on-site best management practices (BMPs) and other engineered structures designed to manage and/or Page 2 of ___ treat stormwater on the Property. On-site BMPs include dispersion and infiltration devices, bioretention, permeable pavements, rainwater harvesting systems, tree retention credit, reduced impervious surface footprint, vegetated roofs and other measures designed to mimic pre-developed hydrology and minimize stormwater runoff on the Property. 2.City of Renton shall have the right to ingress and egress over those portions of the Property necessary to perform inspections of the stormwater facilities and BMPs and conduct maintenance activities specified in this Declaration of Covenant and in accordance with the Renton Municipal Code. City of Renton shall provide at least thirty (30) days’ written notice to the Owners that entry on the Property is planned for the inspection of drainage facilities. After the thirty (30) days, the Owners shall allow the City of Renton to enter for the sole purpose of inspecting drainage facilities. In lieu of inspection by the City, the Owners may elect to engage a licensed civil engineer registered in the state of Washington who has expertise in drainage to inspect the drainage facilities and provide a written report describing their condition. If the engineer option is chosen, the Owners shall provide written notice to the City of Renton within fifteen (15) days of receiving the City’s notice of inspection. Within thirty (30) days of giving this notice, the Owners, or engineer on behalf of the Owners, shall provide the engineer’s report to the City of Renton. If the report is not provided in a timely manner as specified above, the City of Renton may inspect the drainage facilities without further notice. 3.If City of Renton determines from its inspection, or from an engineer’s report provided in accordance with Paragraph 2, that maintenance, repair, restoration, and/or mitigation work is required to be done to any of the drainage facilities, City of Renton shall notify the Owners of the specific maintenance, repair, restoration, and/or mitigation work (“Work”) required pursuant to the Renton Municipal Code. The City shall also set a reasonable deadline for the Owners to complete the Work, or to provide an engineer’s report that verifies completion of the Work. After the deadline has passed, the Owners shall allow the City access to re-inspect the drainage facilities unless an engineer’s report has been provided verifying completion of the Work. If the Work is not completed within the time frame set by the City, the City may initiate an enforcement action and/or perform the Work and hereby is given access to the Property for such purposes. Written notice will be sent to the Owners stating the City’s intention to perform such Work. This Work will not commence until at least seven (7) days after such notice is mailed. If, within the sole discretion of the City, there exists an imminent or present danger, the seven (7) day notice period will be waived and Work will begin immediately. 4.The Owners shall assume all responsibility for the cost of any Work, or any measures taken by the City to address conditions as described in Paragraph 3. Such responsibility shall include reimbursement to the City within thirty (30) days of the receipt of the invoice for any such Work performed. Overdue payments will require payment of interest at the maximum legal rate allowed by RCW 19.52.020 (currently twelve percent (12%)). If the City initiates legal action to enforce this agreement, the prevailing party in such action is entitled to recover reasonable litigation costs and attorney’s fees. 5.The Owners are required to obtain written approval from City of Renton prior to filling, piping, cutting, or removing vegetation (except in routine landscape maintenance) in open vegetated stormwater facilities (such as swales, channels, ditches, ponds, etc.), or performing any alterations or modifications to the drainage facilities referenced in this Declaration of Covenant. Page 3 of ___ 6.Any notice or consent required to be given or otherwise provided for by the provisions of this Agreement shall be effective upon personal delivery, or three (3) days after mailing by Certified Mail, return receipt requested. 7.With regard to the matters addressed herein, this agreement constitutes the entire agreement between the parties, and supersedes all prior discussions, negotiations, and all agreements whatsoever whether oral or written. 8.This Declaration of Covenant is intended to protect the value and desirability and promote efficient and effective management of surface water drainage of the real property described above, and shall inure to the benefit of all the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s), and Grantor's(s') successors in interest, and assigns. 9.This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City that is recorded by King County in its real property records. IN WITNESS WHEREOF, this Declaration of Covenant for the Inspection and Maintenance of Drainage Facilities is executed this _____ day of ____________________, 20_____. GRANTOR, owner of the Property GRANTOR, owner of the Property STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: , to me known to be the individual(s) described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed, for the uses and purposes therein stated. Given under my hand and official seal this _____ day of ___________________, 20_____. Printed name Notary Public in and for the State of Washington, residing at My appointment expires Exhibit B – Operation and Maintenance 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. MAINTENANCE INSTRUCTIONS FOR TREE RETENTION Your property contains an on-site BMP (best management practice) called “tree retention,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces on your property. Tree retention provides flow control via interception, transpiration, and increased infiltration. 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. • Trees should be pruned in an appropriate manner for each species. • Pruning should be performed by landscape professionals familiar with proper pruning techniques. • Dead trees shall be replaced with like species within 30 days (as practical depending on weather/planting season). 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. MAINTENANCE INSTRUCTIONS FOR BASIC DISPERSION Your property contains an on-site BMP (best management practice) called “basic dispersion,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces or non-native pervious surfaces on your property. Basic dispersion is a strategy for utilizing any available capacity of onsite vegetated areas to retain, absorb, and filter the runoff from developed surfaces. This on-site BMP has two primary components that must be maintained: (1) The devices that disperse runoff from the developed surfaces and (2) The vegetated area over which runoff is dispersed. Dispersion Devices The dispersion devices used on your property include the following as indicated on the site plan (CHECK THE BOX(ES) THAT APPLY):  splash blocks,  rock pads,  gravel filled trenches,  sheet flow. MAINTENANCE RESTRICTIONS The size, placement, composition, and downstream flowpaths 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 This on-site BMP has two primary components that must be maintained per Appendix A of the City of Renton’s Surface Water Design Manual: (1) The devices that disperse runoff from the developed surfaces and (2) The vegetated flowpath area over which runoff is dispersed. Maintenance of Dispersion Devices • Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. • When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. • Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. Maintenance of Vegetated Flowpaths • The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows. RECORDING REQUIREMENT These basic dispersion 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. TYPICAL SPLASH BLOCK TYPICAL 10-FOOT DISPERSION TRENCH CROSS-SECTION TYPICAL DRIVEWAY APPLICATION OF DISPERSION TRENCH AND ROCK PAD SIDE VIEWNTS HOUSE DOWNSPOUTEXTENSION SPLASHBLOCK ROOF DOWNSPOUT SPLASH BLOCK 100' MIN. VEGETATEDFLOWPATH UNDERFULL DISPERSION,SEE SECTION C.2.1.3 10-foot long dispersion trench Vegetated Flowpath Segment (NVFS) Slot drain Diagonal asphalt berm – 2 to 4 inches high PLAN VIEW OF DRIVEWAY NTS 2-ft x 3-ft x 6-inch crushed rock pad 50-foot separation between flowpath segments Vegetated Flowpath Segment Edge of undisturbed native vegetation APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-6 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Any trash and debris which exceed 1 cubic foot per 1,000 square feet (this is about equal to the amount of trash it would take to fill up one standard size office garbage can). In general, there should be no visual evidence of dumping. Trash and debris cleared from site. Noxious weeds Any noxious or nuisance vegetation which may constitute a hazard to City personnel or the public. Noxious and nuisance vegetation removed according to applicable regulations. No danger of noxious vegetation where City personnel or the public might normally be. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Excessive growth of grass/groundcover Grass or groundcover exceeds 18 inches in height. Grass or groundcover mowed to a height no greater than 6 inches. Tank or Vault Storage Area Trash and debris Any trash and debris accumulated in vault or tank (includes floatables and non-floatables). No trash or debris in vault. Sediment accumulation Accumulated sediment depth exceeds 10% of the diameter of the storage area for ½ length of storage vault or any point depth exceeds 15% of diameter. Example: 72-inch storage tank would require cleaning when sediment reaches depth of 7 inches for more than ½ length of tank. All sediment removed from storage area. Tank Structure Plugged air vent Any blockage of the vent. Tank or vault freely vents. Tank bent out of shape Any part of tank/pipe is bent out of shape more than 10% of its design shape. Tank repaired or replaced to design. Gaps between sections, damaged joints or cracks or tears in wall A gap wider than ½-inch at the joint of any tank sections or any evidence of soil particles entering the tank at a joint or through a wall. No water or soil entering tank through joints or walls. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Inlet/Outlet Pipes Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipes Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Access Manhole Cover/lid not in place Cover/lid is missing or only partially in place. Any open manhole requires immediate maintenance. Manhole access covered. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-7 NO. 3 – DETENTION TANKS AND VAULTS MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITIONS WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Access Manhole (cont.) Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Large access doors/plate Damaged or difficult to open Large access doors or plates cannot be opened/removed using normal equipment. Replace or repair access door so it can opened as designed. Gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-8 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Structure Trash and debris Trash or debris of more than ½ cubic foot which is located immediately in front of the structure opening or is blocking capacity of the structure by more than 10%. No Trash or debris blocking or potentially blocking entrance to structure. Trash or debris in the structure that exceeds 1/3 the depth from the bottom of basin to invert the lowest pipe into or out of the basin. No trash or debris in the structure. Deposits of garbage exceeding 1 cubic foot in volume. No condition present which would attract or support the breeding of insects or rodents. Sediment accumulation Sediment exceeds 60% of the depth from the bottom of the structure to the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section or is within 6 inches of the invert of the lowest pipe into or out of the structure or the bottom of the FROP-T section. Sump of structure contains no sediment. Damage to frame and/or top slab Corner of frame extends more than ¾ inch past curb face into the street (If applicable). Frame is even with curb. Top slab has holes larger than 2 square inches or cracks wider than ¼ inch. Top slab is free of holes and cracks. Frame not sitting flush on top slab, i.e., separation of more than ¾ inch of the frame from the top slab. Frame is sitting flush on top slab. Cracks in walls or bottom Cracks wider than ½ inch and longer than 3 feet, any evidence of soil particles entering structure through cracks, or maintenance person judges that structure is unsound. Structure is sealed and structurally sound. Cracks wider than ½ inch and longer than 1 foot at the joint of any inlet/outlet pipe or any evidence of soil particles entering structure through cracks. No cracks more than 1/4 inch wide at the joint of inlet/outlet pipe. Settlement/ misalignment Structure has settled more than 1 inch or has rotated more than 2 inches out of alignment. Basin replaced or repaired to design standards. Damaged pipe joints Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering the structure at the joint of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of inlet/outlet pipes. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Ladder rungs missing or unsafe Ladder is unsafe due to missing rungs, misalignment, rust, cracks, or sharp edges. Ladder meets design standards and allows maintenance person safe access. FROP-T Section Damaged FROP-T T section is not securely attached to structure wall and outlet pipe structure should support at least 1,000 lbs of up or down pressure. T section securely attached to wall and outlet pipe. Structure is not in upright position (allow up to 10% from plumb). Structure in correct position. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 2017 City of Renton Surface Water Design Manual 12/12/2016 A-9 NO. 4 – CONTROL STRUCTURE/FLOW RESTRICTOR MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED FROP-T Section (cont.) Damaged FROP-T (cont.) Connections to outlet pipe are not watertight or show signs of deteriorated grout. Connections to outlet pipe are water tight; structure repaired or replaced and works as designed. Any holes—other than designed holes—in the structure. Structure has no holes other than designed holes. Cleanout Gate Damaged or missing cleanout gate Cleanout gate is missing. Replace cleanout gate. Cleanout gate is not watertight. Gate is watertight and works as designed. Gate cannot be moved up and down by one maintenance person. Gate moves up and down easily and is watertight. Chain/rod leading to gate is missing or damaged. Chain is in place and works as designed. Orifice Plate Damaged or missing orifice plate Control device is not working properly due to missing, out of place, or bent orifice plate. Plate is in place and works as designed. Obstructions to orifice plate Any trash, debris, sediment, or vegetation blocking the plate. Plate is free of all obstructions and works as designed. Overflow Pipe Obstructions to overflow pipe Any trash or debris blocking (or having the potential of blocking) the overflow pipe. Pipe is free of all obstructions and works as designed. Deformed or damaged lip of overflow pipe Lip of overflow pipe is bent or deformed. Overflow pipe does not allow overflow at an elevation lower than design Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Metal Grates (If applicable) Unsafe grate opening Grate with opening wider than 7/8 inch. Grate opening meets design standards. Trash and debris Trash and debris that is blocking more than 20% of grate surface. Grate free of trash and debris. footnote to guidelines for disposal Damaged or missing grate Grate missing or broken member(s) of the grate. Grate is in place and meets design standards. Manhole Cover/Lid Cover/lid not in place Cover/lid is missing or only partially in place. Any open structure requires urgent maintenance. Cover/lid protects opening to structure. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs. of lift. Cover/lid can be removed and reinstalled by one maintenance person. APPENDIX A MAINTENANCE REQUIREMENTS FOR STORMWATER FACILITIES AND ON-SITE BMPS 12/12/2016 2017 City of Renton Surface Water Design Manual A-24 NO. 17 – WETVAULT MAINTENANCE COMPONENT DEFECT OR PROBLEM CONDITION WHEN MAINTENANCE IS NEEDED RESULTS EXPECTED WHEN MAINTENANCE IS PERFORMED Site Trash and debris Trash and debris accumulated on facility site. Trash and debris removed from facility site. Treatment Area Trash and debris Any trash and debris accumulated in vault (includes floatables and non-floatables). No trash or debris in vault. Sediment accumulation Sediment accumulation in vault bottom exceeds the depth of the sediment zone plus 6 inches. No sediment in vault. Contaminants and pollution Any evidence of contaminants or pollution such as oil, gasoline, concrete slurries or paint. Materials removed and disposed of according to applicable regulations. Source control BMPs implemented if appropriate. No contaminants present other than a surface oil film. Vault Structure Damage to wall, frame, bottom, and/or top slab Cracks wider than ½-inch, any evidence of soil entering the structure through cracks, vault does not retain water or qualified inspection personnel determines that the vault is not structurally sound. Vault is sealed and structurally sound. Baffles damaged Baffles corroding, cracking, warping and/or showing signs of failure or baffle cannot be removed. Repair or replace baffles or walls to specifications. Ventilation area blocked/plugged Ventilation area blocked or plugged. No reduction of ventilation area exists. Inlet/Outlet Pipe Sediment accumulation Sediment filling 20% or more of the pipe. Inlet/outlet pipes clear of sediment. Trash and debris Trash and debris accumulated in inlet/outlet pipes (includes floatables and non-floatables). No trash or debris in pipes. Damaged inlet/outlet pipe Cracks wider than ½-inch at the joint of the inlet/outlet pipes or any evidence of soil entering at the joints of the inlet/outlet pipes. No cracks more than ¼-inch wide at the joint of the inlet/outlet pipe. Gravity Drain Inoperable valve Valve will not open and close. Valve opens and closes normally. Valve won’t seal Valve does not seal completely. Valve completely seals closed. Access Manhole Access cover/lid damaged or difficult to open Access cover/lid cannot be easily opened by one person. Corrosion/deformation of cover/lid. Access cover/lid can be opened by one person. Locking mechanism not working Mechanism cannot be opened by one maintenance person with proper tools. Bolts cannot be seated. Self-locking cover/lid does not work. Mechanism opens with proper tools. Cover/lid difficult to remove One maintenance person cannot remove cover/lid after applying 80 lbs of lift. Cover/lid can be removed and reinstalled by one maintenance person. Access doors/plate has gaps, doesn't cover completely Large access doors not flat and/or access opening not completely covered. Doors close flat; covers access opening completely. Lifting rings missing, rusted Lifting rings not capable of lifting weight of door or plate. Lifting rings sufficient to lift or remove door or plate. Ladder rungs unsafe Missing rungs, misalignment, rust, or cracks. Ladder meets design standards. Allows maintenance person safe access. Skattum Renton Plat Technical Information Report APPENDIX H FLOW CONTROL & WATER QUALITY FACILITY SUMMARY SHEET & SKETCH PUBLIC106TH AVE SE LUA 16-0009811700 NW GILMAN BLVD, STE 200ISSAQUAH, WA 98027PHONE: (425) 821-5038Know what'sCallbelow.before you dig.RRenton Subdivision Renton SubdivisionSheet 7 Renton Subdivision17018 & 17022 106th Avenue SERenton, WA 98055DETENTION TANK DETAILSTED-40-4041 R-404106C:18-006046 PR:17-000022NOTERESTRICTOR SPECIFICATIONSINTERCEPTOR TRENCH DETAIL Skattum Renton Plat Technical Information Report APPENDIX I BACKWATER ANALYSIS Project: Skattum 11-Lot Renton Subdivision Backwater Analysis Date: May 18, 2021 Column (1)Column (2)Column (3)Column (4) Column (5) Column (6) Column (7) Column (8) Column (9) Column (10) Column (11)Column (12)Column (13)Column (14) Column (15) Column (16)Column (17)Column (18)Column (19)Column (20) 100-Year Design Flows (WWHM) Q (cfs) Pipe Length (ft) Pipe Diameter (ft) Pipe n Value Outlet Elev. (ft) Inlet Elev. (ft) Barrel Area (sqft) Barrel Vel. (fps) Barrel Vel. Head (ft) TW Elev. (ft) Friction Loss (ft) Entrance HGL Elev (ft) Entrance Loss Coefficient (Ke) (Table 4.7 Below) Entrance Head Loss (ft) Exit Head loss (ft) Outlet Control Elev. (ft) (dc/D) dc Critical Depth (Fig. 4.14 Below) (ft) Critical Velocity (fps) Inlet Control Elev. (ft) Approach Velocity Head (ft) (Kb) Bend Head Loss (ft) Qx/Qy Kj Junction Head Loss (ft) HW Elev. (ft) Rim Elev. (ft)Overflow? CB3 - Outfall CB4 1.256 82 1 0.012 377.10 388.96 0.79 1.60 0.040 389.96 0.09 390.05 0.50 0.02 0.04 390.11 0.40 0.40 0.83 389.38 0.0397 -0.020 -0.0008 1.8100 0.7801 0.0310 390.10 393.00 Contained CB4 CB9 0.763 131 1 0.012 388.96 394.33 0.79 0.97 0.015 390.10 0.05 390.15 0.50 0.01 0.01 390.17 0.40 0.40 0.50 394.75 0.0147 -1.320 -0.0193 8.0300 1.2871 0.0189 390.15 398.33 Contained CB9 CB11 0.617 68 1 0.012 394.33 394.67 0.79 0.79 0.010 390.15 0.02 390.17 0.50 0.00 0.01 390.19 0.40 0.40 0.41 395.09 0.0096 -0.020 -0.0002 95.7000 1.5568 0.0149 390.19 398.13 Contained CB11 CB12 - Inlet 0.311 18 1 0.012 394.67 395.03 0.79 0.40 0.002 390.19 0.00 390.19 0.50 0.00 0.00 390.20 0.40 0.40 0.20 395.45 0.0024 -1.320 -0.0032 1.8400 0.7866 0.0019 390.19 398.13 Contained Pipe Segment CB to CB BACKWATER CALCULATION NOTES BACKWATER CALCULATION SHEET WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: CB 100 YR Flow Calcs Site Name: Skattum Site Address: 17018 106th ave se City : Renton Report Date: 11/19/2020 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2016/02/25 Version : 4.2.12 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ Low Flow Threshold for POC 2 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 2: 50 year ___________________________________________________________________ Low Flow Threshold for POC 3 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 3: 50 year ___________________________________________________________________ Low Flow Threshold for POC 4 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 4: 50 year ___________________________________________________________________ Low Flow Threshold for POC 5 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 5: 50 year ___________________________________________________________________ Low Flow Threshold for POC 6 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 6: 50 year ___________________________________________________________________ Low Flow Threshold for POC 7 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 7: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : CB-12 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .514 Pervious Total 0.514 Impervious Land Use acre Impervious Total 0 Basin Total 0.514 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-11 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .492 Pervious Total 0.492 Impervious Land Use acre Impervious Total 0 Basin Total 0.492 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-10 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .09 Pervious Total 0.09 Impervious Land Use acre Impervious Total 0 Basin Total 0.09 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-9 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .154 Pervious Total 0.154 Impervious Land Use acre Impervious Total 0 Basin Total 0.154 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-5 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .454 Pervious Total 0.454 Impervious Land Use acre Impervious Total 0 Basin Total 0.454 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-4 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .027 Pervious Total 0.027 Impervious Land Use acre Impervious Total 0 Basin Total 0.027 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-3A Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat .027 Pervious Total 0.027 Impervious Land Use acre Impervious Total 0 Basin Total 0.027 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : CB-12 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .168 Pervious Total 0.168 Impervious Land Use acre ROADS FLAT 0.346 Impervious Total 0.346 Basin Total 0.514 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-11 Bypass: No GroundWater: No Pervious Land Use acre C, Pasture, Flat .205 C, Lawn, Flat .205 Pervious Total 0.41 Impervious Land Use acre ROADS FLAT 0.287 Impervious Total 0.287 Basin Total 0.697 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-10 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .03 Pervious Total 0.03 Impervious Land Use acre ROADS FLAT 0.06 Impervious Total 0.06 Basin Total 0.09 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-9 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .053 Pervious Total 0.053 Impervious Land Use acre ROADS FLAT 0.101 Impervious Total 0.101 Basin Total 0.154 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-5 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .145 Pervious Total 0.145 Impervious Land Use acre ROADS FLAT 0.309 Impervious Total 0.309 Basin Total 0.454 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-4 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .109 Pervious Total 0.109 Impervious Land Use acre ROADS FLAT 0.222 Impervious Total 0.222 Basin Total 0.331 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : CB-3A Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .004 Pervious Total 0.004 Impervious Land Use acre ROADS FLAT 0.023 Impervious Total 0.023 Basin Total 0.027 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.514 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.168 Total Impervious Area:0.346 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.015112 5 year 0.023734 10 year 0.02862 25 year 0.033797 50 year 0.037 100 year 0.039725 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.142695 5 year 0.184513 10 year 0.213442 25 year 0.251503 50 year 0.280998 100 year 0.311504 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.015 0.195 1950 0.019 0.189 1951 0.033 0.121 1952 0.010 0.097 1953 0.008 0.105 1954 0.013 0.116 1955 0.021 0.129 1956 0.017 0.128 1957 0.013 0.152 1958 0.015 0.116 1959 0.013 0.112 1960 0.023 0.126 1961 0.013 0.128 1962 0.008 0.105 1963 0.011 0.124 1964 0.014 0.115 1965 0.010 0.158 1966 0.010 0.099 1967 0.021 0.174 1968 0.013 0.198 1969 0.013 0.144 1970 0.010 0.133 1971 0.011 0.159 1972 0.025 0.178 1973 0.011 0.092 1974 0.012 0.149 1975 0.017 0.154 1976 0.012 0.115 1977 0.001 0.112 1978 0.011 0.141 1979 0.006 0.191 1980 0.023 0.202 1981 0.009 0.148 1982 0.018 0.215 1983 0.016 0.164 1984 0.010 0.108 1985 0.006 0.148 1986 0.026 0.124 1987 0.023 0.189 1988 0.009 0.112 1989 0.006 0.140 1990 0.048 0.298 1991 0.029 0.227 1992 0.011 0.107 1993 0.012 0.089 1994 0.004 0.093 1995 0.017 0.130 1996 0.035 0.150 1997 0.030 0.143 1998 0.007 0.134 1999 0.028 0.295 2000 0.012 0.143 2001 0.002 0.146 2002 0.013 0.192 2003 0.016 0.150 2004 0.021 0.274 2005 0.015 0.126 2006 0.018 0.113 2007 0.036 0.266 2008 0.046 0.223 2009 0.023 0.171 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0484 0.2982 2 0.0464 0.2954 3 0.0360 0.2738 4 0.0354 0.2664 5 0.0333 0.2272 6 0.0296 0.2231 7 0.0292 0.2153 8 0.0278 0.2022 9 0.0262 0.1978 10 0.0248 0.1952 11 0.0235 0.1924 12 0.0232 0.1909 13 0.0228 0.1893 14 0.0225 0.1885 15 0.0211 0.1782 16 0.0208 0.1742 17 0.0205 0.1710 18 0.0185 0.1643 19 0.0181 0.1592 20 0.0179 0.1581 21 0.0168 0.1542 22 0.0166 0.1518 23 0.0165 0.1503 24 0.0163 0.1496 25 0.0162 0.1487 26 0.0152 0.1480 27 0.0150 0.1475 28 0.0148 0.1465 29 0.0143 0.1436 30 0.0133 0.1427 31 0.0130 0.1426 32 0.0129 0.1409 33 0.0128 0.1396 34 0.0128 0.1335 35 0.0127 0.1334 36 0.0125 0.1298 37 0.0122 0.1293 38 0.0120 0.1280 39 0.0117 0.1277 40 0.0117 0.1260 41 0.0113 0.1258 42 0.0112 0.1237 43 0.0111 0.1237 44 0.0108 0.1214 45 0.0105 0.1163 46 0.0105 0.1155 47 0.0103 0.1154 48 0.0102 0.1150 49 0.0100 0.1134 50 0.0098 0.1125 51 0.0094 0.1119 52 0.0091 0.1116 53 0.0085 0.1077 54 0.0079 0.1067 55 0.0067 0.1046 56 0.0063 0.1046 57 0.0060 0.0995 58 0.0059 0.0968 59 0.0039 0.0931 60 0.0021 0.0917 61 0.0014 0.0892 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #2 Total Pervious Area:0.492 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #2 Total Pervious Area:0.41 Total Impervious Area:0.287 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #2 Return Period Flow(cfs) 2 year 0.014465 5 year 0.022718 10 year 0.027395 25 year 0.03235 50 year 0.035416 100 year 0.038024 Flow Frequency Return Periods for Mitigated. POC #2 Return Period Flow(cfs) 2 year 0.126849 5 year 0.168354 10 year 0.198257 25 year 0.238897 50 year 0.271311 100 year 0.305614 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #2 Year Predeveloped Mitigated 1949 0.014 0.181 1950 0.018 0.165 1951 0.032 0.115 1952 0.010 0.081 1953 0.008 0.088 1954 0.012 0.104 1955 0.020 0.113 1956 0.016 0.112 1957 0.013 0.139 1958 0.014 0.101 1959 0.012 0.093 1960 0.022 0.122 1961 0.012 0.116 1962 0.008 0.089 1963 0.010 0.112 1964 0.014 0.102 1965 0.010 0.143 1966 0.009 0.089 1967 0.020 0.167 1968 0.012 0.170 1969 0.012 0.129 1970 0.010 0.120 1971 0.011 0.141 1972 0.024 0.167 1973 0.011 0.079 1974 0.012 0.133 1975 0.016 0.142 1976 0.011 0.106 1977 0.001 0.096 1978 0.010 0.122 1979 0.006 0.160 1980 0.022 0.191 1981 0.009 0.130 1982 0.017 0.202 1983 0.015 0.139 1984 0.010 0.095 1985 0.006 0.127 1986 0.025 0.118 1987 0.022 0.159 1988 0.009 0.093 1989 0.006 0.116 1990 0.046 0.308 1991 0.028 0.218 1992 0.011 0.095 1993 0.011 0.076 1994 0.004 0.077 1995 0.016 0.113 1996 0.034 0.147 1997 0.028 0.133 1998 0.006 0.114 1999 0.027 0.259 2000 0.011 0.127 2001 0.002 0.123 2002 0.012 0.177 2003 0.016 0.143 2004 0.020 0.244 2005 0.015 0.117 2006 0.017 0.107 2007 0.034 0.273 2008 0.044 0.215 2009 0.022 0.142 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #2 Rank Predeveloped Mitigated 1 0.0464 0.3080 2 0.0444 0.2732 3 0.0344 0.2587 4 0.0339 0.2436 5 0.0319 0.2184 6 0.0283 0.2147 7 0.0279 0.2019 8 0.0266 0.1913 9 0.0251 0.1813 10 0.0237 0.1766 11 0.0225 0.1701 12 0.0222 0.1674 13 0.0218 0.1666 14 0.0215 0.1651 15 0.0202 0.1596 16 0.0199 0.1592 17 0.0197 0.1471 18 0.0177 0.1435 19 0.0173 0.1429 20 0.0171 0.1425 21 0.0161 0.1421 22 0.0158 0.1408 23 0.0158 0.1391 24 0.0156 0.1387 25 0.0155 0.1332 26 0.0145 0.1332 27 0.0144 0.1301 28 0.0142 0.1287 29 0.0137 0.1275 30 0.0128 0.1274 31 0.0125 0.1228 32 0.0123 0.1224 33 0.0123 0.1216 34 0.0123 0.1196 35 0.0122 0.1180 36 0.0120 0.1172 37 0.0117 0.1158 38 0.0115 0.1157 39 0.0112 0.1153 40 0.0112 0.1135 41 0.0108 0.1134 42 0.0108 0.1133 43 0.0106 0.1120 44 0.0104 0.1117 45 0.0101 0.1071 46 0.0100 0.1060 47 0.0099 0.1043 48 0.0098 0.1019 49 0.0096 0.1007 50 0.0094 0.0965 51 0.0090 0.0951 52 0.0088 0.0949 53 0.0081 0.0929 54 0.0076 0.0926 55 0.0064 0.0891 56 0.0061 0.0888 57 0.0057 0.0876 58 0.0057 0.0811 59 0.0038 0.0788 60 0.0020 0.0773 61 0.0014 0.0765 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #3 Total Pervious Area:0.09 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #3 Total Pervious Area:0.03 Total Impervious Area:0.06 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #3 Return Period Flow(cfs) 2 year 0.002646 5 year 0.004156 10 year 0.005011 25 year 0.005918 50 year 0.006479 100 year 0.006956 Flow Frequency Return Periods for Mitigated. POC #3 Return Period Flow(cfs) 2 year 0.024802 5 year 0.032097 10 year 0.037146 25 year 0.043793 50 year 0.048946 100 year 0.054278 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #3 Year Predeveloped Mitigated 1949 0.003 0.034 1950 0.003 0.033 1951 0.006 0.021 1952 0.002 0.017 1953 0.001 0.018 1954 0.002 0.020 1955 0.004 0.022 1956 0.003 0.022 1957 0.002 0.026 1958 0.003 0.020 1959 0.002 0.019 1960 0.004 0.022 1961 0.002 0.022 1962 0.001 0.018 1963 0.002 0.022 1964 0.002 0.020 1965 0.002 0.028 1966 0.002 0.017 1967 0.004 0.030 1968 0.002 0.034 1969 0.002 0.025 1970 0.002 0.023 1971 0.002 0.028 1972 0.004 0.031 1973 0.002 0.016 1974 0.002 0.026 1975 0.003 0.027 1976 0.002 0.020 1977 0.000 0.020 1978 0.002 0.024 1979 0.001 0.033 1980 0.004 0.035 1981 0.002 0.026 1982 0.003 0.037 1983 0.003 0.029 1984 0.002 0.019 1985 0.001 0.026 1986 0.005 0.021 1987 0.004 0.033 1988 0.002 0.019 1989 0.001 0.024 1990 0.008 0.052 1991 0.005 0.040 1992 0.002 0.019 1993 0.002 0.015 1994 0.001 0.016 1995 0.003 0.023 1996 0.006 0.026 1997 0.005 0.025 1998 0.001 0.023 1999 0.005 0.051 2000 0.002 0.025 2001 0.000 0.025 2002 0.002 0.033 2003 0.003 0.026 2004 0.004 0.048 2005 0.003 0.022 2006 0.003 0.020 2007 0.006 0.047 2008 0.008 0.039 2009 0.004 0.030 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #3 Rank Predeveloped Mitigated 1 0.0085 0.0520 2 0.0081 0.0514 3 0.0063 0.0476 4 0.0062 0.0465 5 0.0058 0.0396 6 0.0052 0.0389 7 0.0051 0.0375 8 0.0049 0.0352 9 0.0046 0.0344 10 0.0043 0.0340 11 0.0041 0.0335 12 0.0041 0.0331 13 0.0040 0.0329 14 0.0039 0.0327 15 0.0037 0.0310 16 0.0036 0.0304 17 0.0036 0.0297 18 0.0032 0.0285 19 0.0032 0.0277 20 0.0031 0.0275 21 0.0029 0.0267 22 0.0029 0.0264 23 0.0029 0.0262 24 0.0029 0.0260 25 0.0028 0.0259 26 0.0027 0.0257 27 0.0026 0.0256 28 0.0026 0.0254 29 0.0025 0.0250 30 0.0023 0.0248 31 0.0023 0.0248 32 0.0023 0.0245 33 0.0022 0.0242 34 0.0022 0.0232 35 0.0022 0.0232 36 0.0022 0.0225 37 0.0021 0.0225 38 0.0021 0.0222 39 0.0021 0.0222 40 0.0020 0.0219 41 0.0020 0.0219 42 0.0020 0.0215 43 0.0019 0.0215 44 0.0019 0.0211 45 0.0018 0.0202 46 0.0018 0.0201 47 0.0018 0.0201 48 0.0018 0.0200 49 0.0017 0.0197 50 0.0017 0.0195 51 0.0016 0.0194 52 0.0016 0.0194 53 0.0015 0.0187 54 0.0014 0.0185 55 0.0012 0.0182 56 0.0011 0.0182 57 0.0010 0.0173 58 0.0010 0.0168 59 0.0007 0.0162 60 0.0004 0.0159 61 0.0002 0.0155 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #4 Total Pervious Area:0.154 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #4 Total Pervious Area:0.053 Total Impervious Area:0.101 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #4 Return Period Flow(cfs) 2 year 0.004528 5 year 0.007111 10 year 0.008575 25 year 0.010126 50 year 0.011086 100 year 0.011902 Flow Frequency Return Periods for Mitigated. POC #4 Return Period Flow(cfs) 2 year 0.041918 5 year 0.054323 10 year 0.06292 25 year 0.074245 50 year 0.083031 100 year 0.092128 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #4 Year Predeveloped Mitigated 1949 0.004 0.058 1950 0.006 0.055 1951 0.010 0.036 1952 0.003 0.028 1953 0.003 0.031 1954 0.004 0.034 1955 0.006 0.038 1956 0.005 0.038 1957 0.004 0.045 1958 0.005 0.034 1959 0.004 0.033 1960 0.007 0.037 1961 0.004 0.038 1962 0.002 0.031 1963 0.003 0.036 1964 0.004 0.034 1965 0.003 0.047 1966 0.003 0.029 1967 0.006 0.052 1968 0.004 0.058 1969 0.004 0.042 1970 0.003 0.039 1971 0.003 0.047 1972 0.007 0.053 1973 0.003 0.027 1974 0.004 0.044 1975 0.005 0.045 1976 0.004 0.034 1977 0.000 0.033 1978 0.003 0.041 1979 0.002 0.056 1980 0.007 0.060 1981 0.003 0.043 1982 0.005 0.063 1983 0.005 0.048 1984 0.003 0.032 1985 0.002 0.043 1986 0.008 0.036 1987 0.007 0.055 1988 0.003 0.033 1989 0.002 0.041 1990 0.015 0.089 1991 0.009 0.067 1992 0.003 0.031 1993 0.004 0.026 1994 0.001 0.027 1995 0.005 0.038 1996 0.011 0.044 1997 0.009 0.042 1998 0.002 0.039 1999 0.008 0.087 2000 0.004 0.042 2001 0.001 0.043 2002 0.004 0.057 2003 0.005 0.044 2004 0.006 0.081 2005 0.005 0.037 2006 0.005 0.033 2007 0.011 0.079 2008 0.014 0.066 2009 0.007 0.050 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #4 Rank Predeveloped Mitigated 1 0.0145 0.0885 2 0.0139 0.0870 3 0.0108 0.0806 4 0.0106 0.0792 5 0.0100 0.0673 6 0.0089 0.0660 7 0.0087 0.0634 8 0.0083 0.0598 9 0.0078 0.0581 10 0.0074 0.0576 11 0.0070 0.0568 12 0.0069 0.0558 13 0.0068 0.0554 14 0.0067 0.0551 15 0.0063 0.0527 16 0.0062 0.0516 17 0.0062 0.0499 18 0.0055 0.0481 19 0.0054 0.0468 20 0.0054 0.0466 21 0.0050 0.0451 22 0.0050 0.0447 23 0.0050 0.0444 24 0.0049 0.0441 25 0.0048 0.0438 26 0.0045 0.0435 27 0.0045 0.0433 28 0.0044 0.0428 29 0.0043 0.0423 30 0.0040 0.0420 31 0.0039 0.0419 32 0.0039 0.0413 33 0.0038 0.0407 34 0.0038 0.0392 35 0.0038 0.0391 36 0.0038 0.0381 37 0.0037 0.0379 38 0.0036 0.0376 39 0.0035 0.0375 40 0.0035 0.0372 41 0.0034 0.0370 42 0.0034 0.0364 43 0.0033 0.0363 44 0.0032 0.0358 45 0.0031 0.0342 46 0.0031 0.0339 47 0.0031 0.0339 48 0.0031 0.0338 49 0.0030 0.0334 50 0.0029 0.0328 51 0.0028 0.0327 52 0.0027 0.0326 53 0.0025 0.0316 54 0.0024 0.0313 55 0.0020 0.0306 56 0.0019 0.0306 57 0.0018 0.0292 58 0.0018 0.0283 59 0.0012 0.0272 60 0.0006 0.0268 61 0.0004 0.0261 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #5 Total Pervious Area:0.454 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #5 Total Pervious Area:0.145 Total Impervious Area:0.309 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #5 Return Period Flow(cfs) 2 year 0.013348 5 year 0.020964 10 year 0.025279 25 year 0.029852 50 year 0.032681 100 year 0.035087 Flow Frequency Return Periods for Mitigated. POC #5 Return Period Flow(cfs) 2 year 0.127104 5 year 0.164201 10 year 0.189845 25 year 0.223566 50 year 0.249685 100 year 0.276689 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #5 Year Predeveloped Mitigated 1949 0.013 0.174 1950 0.016 0.168 1951 0.029 0.108 1952 0.009 0.086 1953 0.007 0.093 1954 0.012 0.104 1955 0.018 0.115 1956 0.015 0.114 1957 0.012 0.135 1958 0.013 0.103 1959 0.011 0.100 1960 0.020 0.112 1961 0.011 0.114 1962 0.007 0.093 1963 0.010 0.110 1964 0.013 0.103 1965 0.009 0.141 1966 0.009 0.089 1967 0.018 0.155 1968 0.011 0.176 1969 0.011 0.128 1970 0.009 0.119 1971 0.010 0.142 1972 0.022 0.158 1973 0.010 0.082 1974 0.011 0.132 1975 0.015 0.138 1976 0.011 0.102 1977 0.001 0.100 1978 0.009 0.126 1979 0.006 0.170 1980 0.021 0.180 1981 0.008 0.131 1982 0.016 0.192 1983 0.014 0.147 1984 0.009 0.096 1985 0.005 0.132 1986 0.023 0.110 1987 0.020 0.169 1988 0.008 0.100 1989 0.005 0.125 1990 0.043 0.264 1991 0.026 0.202 1992 0.010 0.095 1993 0.010 0.080 1994 0.003 0.083 1995 0.015 0.116 1996 0.031 0.134 1997 0.026 0.127 1998 0.006 0.119 1999 0.025 0.263 2000 0.010 0.127 2001 0.002 0.131 2002 0.011 0.171 2003 0.014 0.133 2004 0.019 0.244 2005 0.013 0.112 2006 0.016 0.101 2007 0.032 0.236 2008 0.041 0.198 2009 0.020 0.153 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #5 Rank Predeveloped Mitigated 1 0.0428 0.2645 2 0.0410 0.2628 3 0.0318 0.2437 4 0.0313 0.2362 5 0.0294 0.2018 6 0.0261 0.1981 7 0.0258 0.1917 8 0.0245 0.1795 9 0.0231 0.1762 10 0.0219 0.1736 11 0.0207 0.1711 12 0.0205 0.1704 13 0.0201 0.1689 14 0.0199 0.1682 15 0.0187 0.1583 16 0.0183 0.1546 17 0.0181 0.1527 18 0.0163 0.1465 19 0.0159 0.1418 20 0.0158 0.1407 21 0.0148 0.1377 22 0.0146 0.1351 23 0.0146 0.1337 24 0.0144 0.1330 25 0.0143 0.1323 26 0.0134 0.1319 27 0.0133 0.1315 28 0.0131 0.1307 29 0.0126 0.1278 30 0.0118 0.1270 31 0.0115 0.1269 32 0.0114 0.1256 33 0.0113 0.1247 34 0.0113 0.1191 35 0.0112 0.1188 36 0.0111 0.1157 37 0.0108 0.1153 38 0.0106 0.1140 39 0.0103 0.1137 40 0.0103 0.1120 41 0.0099 0.1119 42 0.0099 0.1103 43 0.0098 0.1101 44 0.0096 0.1080 45 0.0093 0.1036 46 0.0093 0.1030 47 0.0091 0.1028 48 0.0090 0.1023 49 0.0088 0.1008 50 0.0087 0.1005 51 0.0083 0.0999 52 0.0081 0.0997 53 0.0075 0.0959 54 0.0070 0.0951 55 0.0059 0.0934 56 0.0056 0.0933 57 0.0053 0.0886 58 0.0052 0.0864 59 0.0035 0.0832 60 0.0019 0.0819 61 0.0013 0.0796 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #6 Total Pervious Area:0.027 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #6 Total Pervious Area:0.109 Total Impervious Area:0.222 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #6 Return Period Flow(cfs) 2 year 0.000794 5 year 0.001247 10 year 0.001503 25 year 0.001775 50 year 0.001944 100 year 0.002087 Flow Frequency Return Periods for Mitigated. POC #6 Return Period Flow(cfs) 2 year 0.091635 5 year 0.118526 10 year 0.137134 25 year 0.161619 50 year 0.180597 100 year 0.200229 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #6 Year Predeveloped Mitigated 1949 0.001 0.125 1950 0.001 0.121 1951 0.002 0.078 1952 0.001 0.062 1953 0.000 0.067 1954 0.001 0.075 1955 0.001 0.083 1956 0.001 0.082 1957 0.001 0.098 1958 0.001 0.074 1959 0.001 0.072 1960 0.001 0.081 1961 0.001 0.082 1962 0.000 0.067 1963 0.001 0.079 1964 0.001 0.074 1965 0.001 0.102 1966 0.001 0.064 1967 0.001 0.112 1968 0.001 0.127 1969 0.001 0.092 1970 0.001 0.086 1971 0.001 0.102 1972 0.001 0.115 1973 0.001 0.059 1974 0.001 0.096 1975 0.001 0.099 1976 0.001 0.074 1977 0.000 0.072 1978 0.001 0.090 1979 0.000 0.123 1980 0.001 0.130 1981 0.000 0.095 1982 0.001 0.138 1983 0.001 0.105 1984 0.001 0.069 1985 0.000 0.095 1986 0.001 0.079 1987 0.001 0.122 1988 0.000 0.072 1989 0.000 0.090 1990 0.003 0.192 1991 0.002 0.146 1992 0.001 0.069 1993 0.001 0.057 1994 0.000 0.060 1995 0.001 0.083 1996 0.002 0.097 1997 0.002 0.092 1998 0.000 0.086 1999 0.001 0.190 2000 0.001 0.092 2001 0.000 0.094 2002 0.001 0.124 2003 0.001 0.096 2004 0.001 0.176 2005 0.001 0.081 2006 0.001 0.073 2007 0.002 0.171 2008 0.002 0.143 2009 0.001 0.110 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #6 Rank Predeveloped Mitigated 1 0.0025 0.1918 2 0.0024 0.1898 3 0.0019 0.1759 4 0.0019 0.1714 5 0.0017 0.1461 6 0.0016 0.1434 7 0.0015 0.1383 8 0.0015 0.1299 9 0.0014 0.1270 10 0.0013 0.1254 11 0.0012 0.1236 12 0.0012 0.1225 13 0.0012 0.1215 14 0.0012 0.1210 15 0.0011 0.1145 16 0.0011 0.1120 17 0.0011 0.1097 18 0.0010 0.1054 19 0.0009 0.1022 20 0.0009 0.1016 21 0.0009 0.0989 22 0.0009 0.0975 23 0.0009 0.0966 24 0.0009 0.0961 25 0.0009 0.0955 26 0.0008 0.0950 27 0.0008 0.0947 28 0.0008 0.0940 29 0.0007 0.0923 30 0.0007 0.0916 31 0.0007 0.0916 32 0.0007 0.0905 33 0.0007 0.0896 34 0.0007 0.0857 35 0.0007 0.0856 36 0.0007 0.0833 37 0.0006 0.0830 38 0.0006 0.0822 39 0.0006 0.0820 40 0.0006 0.0809 41 0.0006 0.0808 42 0.0006 0.0794 43 0.0006 0.0794 44 0.0006 0.0780 45 0.0006 0.0747 46 0.0006 0.0742 47 0.0005 0.0741 48 0.0005 0.0738 49 0.0005 0.0729 50 0.0005 0.0722 51 0.0005 0.0718 52 0.0005 0.0716 53 0.0004 0.0692 54 0.0004 0.0685 55 0.0004 0.0672 56 0.0003 0.0672 57 0.0003 0.0639 58 0.0003 0.0621 59 0.0002 0.0598 60 0.0001 0.0588 61 0.0001 0.0573 ___________________________________________________________________ ___________________________________________________________________ Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #7 Total Pervious Area:0.027 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #7 Total Pervious Area:0.004 Total Impervious Area:0.023 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #7 Return Period Flow(cfs) 2 year 0.000794 5 year 0.001247 10 year 0.001503 25 year 0.001775 50 year 0.001944 100 year 0.002087 Flow Frequency Return Periods for Mitigated. POC #7 Return Period Flow(cfs) 2 year 0.009025 5 year 0.011489 10 year 0.013173 25 year 0.015368 50 year 0.017055 100 year 0.018789 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #7 Year Predeveloped Mitigated 1949 0.001 0.012 1950 0.001 0.012 1951 0.002 0.007 1952 0.001 0.006 1953 0.000 0.007 1954 0.001 0.007 1955 0.001 0.008 1956 0.001 0.008 1957 0.001 0.009 1958 0.001 0.007 1959 0.001 0.007 1960 0.001 0.008 1961 0.001 0.008 1962 0.000 0.007 1963 0.001 0.008 1964 0.001 0.007 1965 0.001 0.010 1966 0.001 0.006 1967 0.001 0.011 1968 0.001 0.013 1969 0.001 0.009 1970 0.001 0.008 1971 0.001 0.010 1972 0.001 0.011 1973 0.001 0.006 1974 0.001 0.009 1975 0.001 0.010 1976 0.001 0.007 1977 0.000 0.007 1978 0.001 0.009 1979 0.000 0.013 1980 0.001 0.012 1981 0.000 0.009 1982 0.001 0.013 1983 0.001 0.011 1984 0.001 0.007 1985 0.000 0.009 1986 0.001 0.008 1987 0.001 0.012 1988 0.000 0.007 1989 0.000 0.009 1990 0.003 0.017 1991 0.002 0.013 1992 0.001 0.007 1993 0.001 0.006 1994 0.000 0.006 1995 0.001 0.008 1996 0.002 0.009 1997 0.002 0.009 1998 0.000 0.009 1999 0.001 0.018 2000 0.001 0.009 2001 0.000 0.010 2002 0.001 0.012 2003 0.001 0.009 2004 0.001 0.017 2005 0.001 0.008 2006 0.001 0.007 2007 0.002 0.016 2008 0.002 0.013 2009 0.001 0.011 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #7 Rank Predeveloped Mitigated 1 0.0025 0.0182 2 0.0024 0.0171 3 0.0019 0.0170 4 0.0019 0.0159 5 0.0017 0.0134 6 0.0016 0.0134 7 0.0015 0.0132 8 0.0015 0.0126 9 0.0014 0.0125 10 0.0013 0.0124 11 0.0012 0.0124 12 0.0012 0.0120 13 0.0012 0.0119 14 0.0012 0.0117 15 0.0011 0.0113 16 0.0011 0.0110 17 0.0011 0.0107 18 0.0010 0.0107 19 0.0009 0.0102 20 0.0009 0.0100 21 0.0009 0.0097 22 0.0009 0.0096 23 0.0009 0.0094 24 0.0009 0.0094 25 0.0009 0.0094 26 0.0008 0.0093 27 0.0008 0.0092 28 0.0008 0.0092 29 0.0007 0.0091 30 0.0007 0.0091 31 0.0007 0.0090 32 0.0007 0.0089 33 0.0007 0.0088 34 0.0007 0.0086 35 0.0007 0.0084 36 0.0007 0.0083 37 0.0006 0.0083 38 0.0006 0.0082 39 0.0006 0.0080 40 0.0006 0.0080 41 0.0006 0.0078 42 0.0006 0.0077 43 0.0006 0.0077 44 0.0006 0.0075 45 0.0006 0.0074 46 0.0006 0.0074 47 0.0005 0.0074 48 0.0005 0.0074 49 0.0005 0.0074 50 0.0005 0.0073 51 0.0005 0.0072 52 0.0005 0.0069 53 0.0004 0.0069 54 0.0004 0.0068 55 0.0004 0.0068 56 0.0003 0.0068 57 0.0003 0.0064 58 0.0003 0.0064 59 0.0002 0.0062 60 0.0001 0.0061 61 0.0001 0.0058 ___________________________________________________________________ ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ 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. 2005-2020; All Rights Reserved.