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Home My WebLink AboutRS_Technical_Information_Report_210128_V1LITCHFIELD ENGINEERING Civil Engineering & Development Services TECHNICAL INFORMATION REPORT for the GREEN’S LANDING SHORT PLAT Prepared for: Pacific Crest Realty Advisors, LLC 10900 NE 4th Street, Suite 2300 Bellevue, WA 98004 Prepared By: Keith A. Litchfield, P.E. Date Issued: March 20, 2019 Date Revised: October 22, 2020 12840 81ST AVENUE NE  KIRKLAND, WA 98034 PH 425-821-5038 FAX 425-821-5739 i Contents SECTION 1: Project Overview ....................................................................................... 6 SECTION 2: Core and Special Requirements Summary ........................................... 10 SECTION 3: Offsite Analysis ....................................................................................... 12 SECTION 4: Flow Control, LID, and Water Quality Facility Analysis and Design .... 14 SECTION 5: Conveyance System Analysis and Design ............................................ 21 SECTION 6: Special Reports and Studies .................................................................. 22 SECTION 7: Other Permits .......................................................................................... 22 SECTION 8: CSWPP Analysis and Design ................................................................. 22 SECTION 9: Bond Quantities, Facility Summaries, and Declaration of Covenant .. 24 SECTION 10: Operations and Maintenance Manual ................................................. 24 FIGURES Figure 1 – TIR Worksheet Figure 2 – Vicinity Map Figure 3 – Drainage Basin & Site Characteristics Figure 4 – Soils Map APPENDICIES Appendix A – WWHM Analysis Appendix B – Operations & Maintenance Manual Appendix C – Pacific Engineering Design, LLC Offsite Analysis Appendix D – Geotechnical Report Appendix E – 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 CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Land Use (e.g., Subdivision / Short Subd.)  Building (e.g., M/F / Commercial / SFR)  Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified __________________ __________________ __________________ Pacific Crest Realty Advisors, LLC (425)830-6962 10900 NE 4th St, Suite 2300 Bellevue, WA Keith Litchfield, PE Litchfield Engineering 425-821-5038 Green's Landing SP 23N 5E 15 5008 NE 2nd Street Renton, WA 98059 x Civil Construction Permit x x NPDES x 3-20-2019 3-20-2019 x FIGURE 1: Rev. 10-22-2020 Rev. 6-20-2019 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ Newcastle Lower Cedar River REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ On-site BMPs: _______________________________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ AgC, Alderwood 0-15%Minimal Project Site 1 1-27-15 (Pacific Engineering) 12-31-18 (Litchfield Engineering) Infiltration Trenches/Permeable pavement Flow Control Duration Standard-Matching Forested TBD TBD REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: N/A N/A REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Control Pollutants  Protect Existing and Proposed BMPs/Facilities  Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary  Flag limits of sensitive areas and open space preservation areas  Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ____________________________  Cast in Place Vault  Retaining Wall  Rockery > 4′ High  Structural on Steep Slope  Other _______________________________ x x x x x x x x Vault Infiltration Trenches/ Permeable pavement x x Wetvault x x x REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6 Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date 10-22-2020 6 SECTION 1: Project Overview This Technical Information Report is submitted in support of the Green’s Landing Short Plat located at 5008 NE 2nd Street (Tax Parcel #: 152305-9219), see Figure 1 - Vicinity Map below. The existing parcel is 50,534 SF (1.16 acres). The property is bordered along the north and west by single family residences, NE 2nd Street to the south, and Hoquiam Ave NE to the east. The site is presently developed with a single-family residence. Besides the existing residence, outbuildings and associated driveway, the site is vegetated with grass and trees. The existing structures and driveway will be removed. The site generally slopes across the property from the northeast to the southwest at an average grade of approximately 7%. There are no critical areas on-site. Project improvements will consist of on & off-site infrastructure improvements to support the future construction of 6 single family residential building lots. After the required ROW dedication along Hoquiam Ave NE the parcel area is approximately 0.91 acres. The total area of project disturbance (onsite work and frontage improvements) is 56,435 SF (1.29 acres). Figure 2 – Vicnity Map SITE N 7 Figure 3a – Drainage Basin and Site Characteristics (USGA scale 1:24,000) SITE Point of Discharge to public ditch (Approx. 234 feet west of the site) 8 Figure 3b – Drainage Basin and Site Characteristics Existing flow (Typ.) SITE (1.29 AC) (No Sub-basins) Proposed storm system Proposed Detention /Water Quality Vault Approx. 430 LF from proposed storm system to proposed flow control facility Note: Individual lot drainage will be collected and tightlined to proposed infiltration trenches w/ overflows to the proposed storm system. 9 Figure 4 – Soils Map Soils: The SCS Soils map indicates the site is underlain with AgC (Alderwood) soils. Please note that there is no significant drainage from the north. SITE 10 SECTION 2: Core and Special Requirements Summary Per Figure 1.1.2.A – Flow Chart for Determining Type of Drainage Review Required of the 2017 City of Renton Surface Water Design Manual the project requires Directed Drainage Review. See below for Figure 1.1.2.A. Per Section 1.1.2.3 Directed Drainage Review requires the project to comply with all nine core requirements and all six special requirements. 11 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 point of discharge located downstream of the project site. Currently the conveyance system abutting the project site is a grass/dirt lined ditch that is approximately 2’ wide by 1’ deep. The ditch is proposed to be replaced with 12” CPEP and backfilled with gravel. Discharge will be made to a new catch basin at the location of an existing 18” culvert approximately 240 feet to the west of the 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 private combined detention/water quality vault. See Section 4. 4. Core Req. #4 – Conveyance System The proposed on-site conveyance and tightline system will route runoff to the proposed detention vault. The detention vault will outlet to the proposed conveyance system within NE 2nd Street. Please refer to Section 5 for a capacity analysis. 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 and detention/water quality vault 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 private combined detention and wetvault system to meet the water quality requirement. 9. Core Req. #9 – On-Site BMPs Proposed on-site BMPs consist of permeable pavement and limited infiltration trenches. 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. 12 13. Special Req. #4 – Source Controls Not applicable to this project 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 December 31, 2018. The weather was sunny; the temperature was approximately 50 degrees. Prior to performing the site reconnaissance, the City of Renton GIS Mapping and the Offsite Analysis within the Preliminary TIR prepared by Pacific Engineering Design, LLC, dated January 2, 2018, was reviewed. Litchfield Engineering concurs with the Offsite Analysis prepared by Pacific Engineering Design, LLC. Please see below for a summary of the downstream system. Please refer to Appendix C for the Offsite Analysis prepared by Pacific Engineering Design, LLC. Upstream Analysis: Based on topography, there are no significant upstream tributary areas to the site. Upstream runoff to the north and east is intercepted by the existing conveyance system within Hoquiam Ave NE. Runoff from the site sheet flows to the southwest towards NE 2nd Street and is collected in the existing public conveyance ditch. The existing ditch conveys runoff to the west for approximately 240 feet before entering an existing 18” public concrete culvert. The existing culvert directs runoff to the south for approximately 50 feet before discharging to Maplewood Creek. The creek conveys runoff in the southeasterly direction for 356 feet before entering an existing 18” concrete culvert. The creek is then conveyed to the south through the culvert for 88 feet before continuing in the southern direction via an open channel for approximately 260 feet. The creek continues to the south via a concrete culvert for approximately 75 feet before being redirected to the west via 36” conveyance pipe for approximately 335 feet. Runoff is then directed to the south via 36” conveyance pipe for approximately 630 feet. The field reconnaissance was terminated as the investigation exceeded the required ¼ mile point analysis. Please note that the creek was not observed during the field reconnaissance due to right of entry. Downstream Concerns & Effects of Proposed Project: Drainage from the developed site will be detained onsite and discharged to the existing public conveyance system within NE 2nd Street. 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. 13 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 Panel Map # 53033C0982F, the site is not located within a flood hazard area. Other Offsite Analysis Reports – The Offsite Analysis within the Preliminary TIR prepared by Pacific Engineering Design, LLC, dated January 2, 2018 was reviewed. Sensitive Areas - The City of Renton online mapping was reviewed and there are no sensitive areas on or adjacent to the site. Downstream Complaints – There are no known downstream drainage complaints. Road Drainage – There are no known road drainage complaints. King County Soils Survey - The on-site soils are AgC-Alderwood gravelly sandy loam, 8 to 15 percent slopes, per the US Department of Agriculture. Wetlands Inventory - There are no wetlands located on-site. Migrating River Studies - There are no known migrating rivers in the resource review area. Section 303d list of polluted waters – There is an unnamed creek within the Maplewood Golf Course located approximately 0.95 miles from the site that is listed as a Category 5 water body per the Water Quality Assessment Map on the DOE website. KC designated water quality problems - There are no known King County designated water quality problems within the area. Stormwater compliance plans - Not applicable to this project. 14 SECTION 4: Flow Control, LID, 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 matches the flow duration of pre-developed rates for forested (historic) site conditions over the range of flows extending from 50% of 2-year up to the full 50-year flow and matches peaks for the 2- and 10-year return periods. A private 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. The detention vault was sized assuming maximum impervious allowed per zoning (65%) and by implementing flow control BMP credits (limited infiltration and permeable pavement). Below are the areas used in the analysis; please refer to Appendix A for the complete WWHM analysis. Given the site topography approximately 1,700 SF of the improved NE 2nd Street ROW could not be conveyed to the detention vault. See the Existing and Developed Conditions Maps on the following pages for additional information. Predeveloped Conditions: On-Site: Area Forest = 1.160 acre Off-Site (Hoquiam Ave & 2nd St): Area Forest = 0.136 acre Total Project (On & Off-Site) Area Forest = 1.296 acre Developed Conditions w/ Flow Control BMP Credits: Please see below for a summary of the developed areas with flow control BMP credits implemented for permeable pavement (50% credit) and limited infiltration (10% credit). Please refer to the following page for a more detailed summary of on and off-site areas. On-Site (after dedication): Impervious = 0.532 acre Pervious = 0.382 acre Total Onsite = 0.914 acre Off-Site (after dedication): Impervious = 0.251 acre Pervious = 0.092 acre Total Offsite = 0.343 acre Off-Site Bypass (after dedication): Impervious = 0.032 acre Pervious = 0.007 acre Total Bypass = 0.039 acre 15 Total Project: Impervious = 0.815 acre Pervious = 0.481 acre Total Area = 1.296 acre Table 1: Developed Areas (after dedication) Area Description Area (SF) Notes Onsite: Lot 1: SF Roof*= 1,885 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 1,189 Total Impervious (65%) = 3,474 Total Pervious (35%) = 1,870 Total Lot Area = 5,344 Lot 2: Roof*= 2,631 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 858 Total Impervious (65%) = 3,889 Total Pervious (35%) = 2,094 Total Lot Area = 5,983 Lot 3: Roof*= 2,523 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 885 Total Impervious (65%) = 3,808 Total Pervious (35%) = 2,051 Total Lot Area = 5,859 Lot 4: Roof*= 1,850 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 1,195 Total Impervious (65%) = 3,445 Total Pervious (35%) = 1,855 Total Lot Area = 5,300 Lot 5: Roof*= 2,135 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 649 Total Impervious (65%) = 3,184 Total Pervious (35%) = 1,715 Total Lot Area = 4,899 16 Lot 6: Roof*= 1,860 Limited Infiltration Driveway = 400 Permeable Pavement Misc. Impervious = 1,046 Total Impervious (65%) = 3,306 Total Pervious (35%) = 1,780 Total Lot Area = 5,086 Tract A: Impervious = 1,380 Permeable Pavement Pervious = 0 Total Area = 1,380 Tract B: Impervious (65%) = 3,872 Pervious (35%) = 2,085 Total Area = 5,957 Offsite: Impervious = 9,571 Pervious = 3,711 Total Offsite Area = 13,282 Offsite Bypass: Impervious = 1,400 Pervious = 300 Total Offsite Bypass = 1,700 * The roof area for each lot is the max allowable per the building setback lines. 17 Existing Conditions Map N C, Forest, Flat = 1.296 Acres Total Project Site = 1.296 Acres 18 Developed Conditions Map N Basin: Impervious, Flat = 0.783 Acres C, Lawn, Flat = 0.474 Acres Total = 1.257 Acres Bypass: Impervious, Flat = 0.032 Acres C, Lawn, Flat = 0.007 Acres Total = 0.039 Acres Total Project Site = 1.296 Acres Bypass 19 Detention System: Per the WWHM analysis a 38.90’ x 60.20’ (inside dimensions) vault with 8’ of live storage is proposed. The 12” flow control restrictor is 8’ tall and located 0.5’ from the bottom of the hollow core panels to provide freeboard. The restrictor has three orifices, please see below for the WWHM analysis showing the orifice heights and diameters. The finish grade over the vault will be approximately 402.00, allowing for a minimum cover of 2’ over the vault. The depth from finish grade to vault invert is 4.26’. The vault has 4’ of dead storage to provide water quality. See below for the water quality design. 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 private 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 vault is separated into two cells through the use of a baffle wall. The highest point of the vault bottom shall be at least 6” below the outlet elevation to provide sediment storage over the entire bottom. The wet vault was designed as detailed in the 2017 Renton Surface Water Design Manual Section 6.4.1.1 and is greater than the 91% water quality treatment volume calculated with the approved model. This volume per WWHM is 0.1103 acre- feet or 4,805 CF. Given the dimensions of the vault (38.9’ x 60.2’), the required depth for water quality is 2.05’. However, per City of Renton Standard Plan 254.00, the minimum water quality depth for a combined system is 4’. The overall vault is 60.2’ long by 38.9’ wide with the depth varying from 13’ to 13.5’ (inside dimensions). The vault provides approximately 18,734 CF of live storage and 9,367 CF of water quality storage. Appendix A provides complete details of the WWHM analysis. 20 On-site 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 the maximum extent feasible in order 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 Infiltration Testing and Subsurface Conditions Report prepared by The Riley Group, Inc., the area available for a full infiltration system is underlain by very dense lodgment till at a depth of 3 feet below grade. Please refer to Appendix D 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: • Limited Infiltration: Will be implemented for all proposed roof areas (12,884 SF), see the following page for trench sizing. • Rain Gardens: Infeasible. The area available for siting a rain garden for the proposed driveway on each lot cannot met the required setbacks from structures, property lines, or proposed roof downspout infiltration trenches. The maximum slope of 7% can also not be met on Lot 6. • Bioretention: Infeasible. The area available for siting a bioretention facility for the proposed driveway on each lot cannot met the required setbacks from structures, property lines, or proposed roof downspout infiltration trenches. The maximum slope of 7% can also not be met on Lot 6. • Permeable Pavement: Will be implemented for all driveways (2,000 SF), including Tract A (1,380 SF) and Tract B (120 SF). 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. N/A – All target impervious surfaces are mitigated by Requirement 3. 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 • Native Growth Retention Credit • Tree Retention Credit N/A – All target impervious surfaces are mitigated by Requirement 3. 6. Soil amendment is required for all new pervious surfaces. A callout and soil amendment notes are provided on Sheet 3, Grading Plan. 7. Perforated pipe connection: N/A – The roof downspouts are be routed to limited infiltration trenches. 21 Limited Infiltration Trench Sizing: Per Section C.2.3.3 of the 2017 City of Renton Surface Water Design Manual, limited infiltration trenches located in fine sand/loamy sand must be at least 21 LF per 1,000 SF of impervious surface served, have at least 18” of washed drain rock, and be a minimum of 2’ wide. This is equivalent to 63 CF of washed drain rock per 1,000 SF of impervious surface served. Please see below for a table showing the sizing calculations used. Table 2: Limited Infiltration Trench Sizing Lot # Tributary Area (SF) Calculation Required Volume (CF) Provided Volume (CF) Trench Dimensions 1 1,885 (1,885 SF/1,000 SF) x 63 CF 119 126 28' L x 3' W x 1.5' D 2 2,631 (2,631 SF/1,000 SF) x 63 CF 166 168 28' L x 4' W x 1.5' D 3 2,523 (2,523 SF/1,000 SF) x 63 CF 159 162 27' L x 4' W x 1.5' D 4 1,850 (1,850 SF/1,000 SF) x 63 CF 117 121.5 27' L x 3' W x 1.5' D 5 2,135 (2,135 SF/1,000 SF) x 63 CF 135 135 30' L x 3' W x 1.5' D 6 1,860 (1,860 SF/1,000 SF) x 63 CF 117 121.5 27' L x 3' W x 1.5' D SECTION 5: Conveyance System Analysis and Design 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 flow using WWHM from the developed site was compared to the maximum capacity of the pipe. Using Manning’s Equation, the maximum capacity of a 12” pipe sloped at 0.50% is 2.98 cfs, which is greater than the actual 100-year flow of 0.75 cfs (see WWHM output below). Since all pipes within the proposed conveyance system are sloped at grades equal to or steeper than 0.50%, the system will have adequate capacity to convey the generated runoff. WWHM Output: Mitigated Landuse Totals for POC #1 Total Pervious Area:0.467 Total Impervious Area:0.813 ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.340191 5 year 0.442137 10 year 0.512939 25 year 0.606376 50 year 0.678981 100 year 0.754237 22 SECTION 6: Special Reports and Studies • Infiltration Testing and Subsurface Conditions; The Riley Group; October 18, 2018 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 system will be required from King County Water District #90. SECTION 8: CSWPP Analysis and Design a. Erosion Sediment Control Plan 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 KCSWDM D.2.1.2.4 when necessary. Perimeter Protection- Filter fencing per KCSWDM 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. Sediment Trap Sizing: The sediment trap has been sized according to Section D.2.1.5.1 of the RSWDM using the developed conditions 2-year peak discharge. Please see below and the following page for the WWHM output and sediment trap surface area sizing. SA = 2 x Q2 / 0.00096 where SA = required surface area at top of riser Q2 = 0.327 CFS (see WWHM output below) SA = (2 x 0.327) / 0.00096 = 775 SF 23 WWHM Output: MITIGATED LAND USE Name : South Bain Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .46 Pervious Total 0.46 Impervious Land Use acre ROADS FLAT 0.781 Impervious Total 0.781 Basin Total 1.241 __________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.32758 5 year 0.426106 10 year 0.494577 25 year 0.584985 50 year 0.655267 100 year 0.728141 ___________________________________________________________________ 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- Dewatering is not anticipated per the geotechnical report. Dust Control- Dust control will be implemented per KCSWDM 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. Control Pollutants- No pollutants will be stored onsite, but a spill kit shall be retained onsite in case of any fuel spills from construction equipment. Protect Existing and Proposed Flow Control BMPs- The locations for permeable pavement and limited infiltration shall be protected from sedimentation and compaction during construction to the maximum extent feasible. When feasible the areas shall be fenced off and heavy equipment shall not be allowed. 24 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. b. Stormwater Pollution Prevention and Spill Plan Storage and Handling of Liquids – Not applicable, since no petroleum products, fuels, solvents, detergents, paint, pesticides, concrete admixtures, or form oils will be handled or stored on the project site. Storage and Stockpiling of Construction Materials and Wastes – Soil stockpiles will be covered with plastic when necessary during periods of rainfall. No pollution generating waste is expected to result from the project. Fueling – Although expected to be minimal, onsite transfer of fuel to construction equipment will be limited to pickup truck-mounted DOT approved fuel tanks. The refueling of equipment will be conducted within the areas of disturbance delineated on the TESC Plan. Maintenance, Repairs, and Storage of Vehicles and Equipment – The contractor shall provide drip pans under equipment being stored overnight or on a prolonged basis. No repairs to vehicles will take place on site. Concrete Saw Cutting, Slurry, and Washwater Disposal – No truck washout area or associated sump is required for the project site. Contractor shall provide truck mounted hand tool rinsing tub for cleaning screeds, shovels, rakes, floats and trowels. Wastewater from hand tool rinsing shall be disposed of offsite. Handling of pH Elevated Water – Upon completion of the concrete vault the finished interior concrete surface to be coated and sealed with Thoroseal water proof cement based coating with acryl 60 additive. Application of Chemicals Including Pesticides and Fertilizers – Not applicable, since no chemicals will be used on the project site. SECTION 9: Bond Quantities, Facility Summaries, and Declaration of Covenant Bond Quantity Worksheet – Appendix E Declaration of Covenant for Privately Maintained Flow Control and Water Quality Features – Appendix F Flow Control and Water Quality Facility Summary Sheet and Sketch – Appendix G SECTION 10: Operations and Maintenance Manual A draft Operations & Maintenance Manual is provided in Appendix B. APPENDIX A WWHM HYDROLOGIC ANALYSES WWHM2012 PROJECT REPORT Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 2 General Model Information Project Name:Green's Short Plat Vault 6-18-19 Site Name:Green Short Plat Site Address:5008 NE 2nd Street City:Renton Report Date:6/19/2019 Gage:Seatac Data Start:1948/10/01 Data End:2009/09/30 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:50 Percent of the 2 Year High Flow Threshold for POC1:50 Year Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 1.296 Pervious Total 1.296 Impervious Land Use acre Impervious Total 0 Basin Total 1.296 Element Flows To: Surface Interflow Groundwater Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 4 Mitigated Land Use South Bain Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.474 Pervious Total 0.474 Impervious Land Use acre ROADS FLAT 0.783 Impervious Total 0.783 Basin Total 1.257 Element Flows To: Surface Interflow Groundwater Vault 1 Vault 1 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 5 Bypass Bypass:Yes GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.007 Pervious Total 0.007 Impervious Land Use acre ROADS FLAT 0.032 Impervious Total 0.032 Basin Total 0.039 Element Flows To: Surface Interflow Groundwater Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 6 Routing Elements Predeveloped Routing Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 7 Mitigated Routing Vault 1 Width:60.2 ft. Length:38.9 ft. Depth:9 ft. Discharge Structure Riser Height:8 ft. Riser Diameter:12 in. Orifice 1 Diameter:0.5625 in.Elevation:0 ft. Orifice 2 Diameter:0.5 in.Elevation:4.4 ft. Orifice 3 Diameter:0.5 in.Elevation:5.5 ft. Element Flows To: Outlet 1 Outlet 2 Vault Hydraulic Table Stage(feet)Area(ac.)Volume(ac-ft.)Discharge(cfs)Infilt(cfs) 0.0000 0.053 0.000 0.000 0.000 0.1000 0.053 0.005 0.002 0.000 0.2000 0.053 0.010 0.003 0.000 0.3000 0.053 0.016 0.004 0.000 0.4000 0.053 0.021 0.005 0.000 0.5000 0.053 0.026 0.006 0.000 0.6000 0.053 0.032 0.006 0.000 0.7000 0.053 0.037 0.007 0.000 0.8000 0.053 0.043 0.007 0.000 0.9000 0.053 0.048 0.008 0.000 1.0000 0.053 0.053 0.008 0.000 1.1000 0.053 0.059 0.009 0.000 1.2000 0.053 0.064 0.009 0.000 1.3000 0.053 0.069 0.009 0.000 1.4000 0.053 0.075 0.010 0.000 1.5000 0.053 0.080 0.010 0.000 1.6000 0.053 0.086 0.010 0.000 1.7000 0.053 0.091 0.011 0.000 1.8000 0.053 0.096 0.011 0.000 1.9000 0.053 0.102 0.011 0.000 2.0000 0.053 0.107 0.012 0.000 2.1000 0.053 0.112 0.012 0.000 2.2000 0.053 0.118 0.012 0.000 2.3000 0.053 0.123 0.013 0.000 2.4000 0.053 0.129 0.013 0.000 2.5000 0.053 0.134 0.013 0.000 2.6000 0.053 0.139 0.013 0.000 2.7000 0.053 0.145 0.014 0.000 2.8000 0.053 0.150 0.014 0.000 2.9000 0.053 0.155 0.014 0.000 3.0000 0.053 0.161 0.014 0.000 3.1000 0.053 0.166 0.015 0.000 3.2000 0.053 0.172 0.015 0.000 3.3000 0.053 0.177 0.015 0.000 3.4000 0.053 0.182 0.015 0.000 3.5000 0.053 0.188 0.016 0.000 3.6000 0.053 0.193 0.016 0.000 3.7000 0.053 0.198 0.016 0.000 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 8 3.8000 0.053 0.204 0.016 0.000 3.9000 0.053 0.209 0.017 0.000 4.0000 0.053 0.215 0.017 0.000 4.1000 0.053 0.220 0.017 0.000 4.2000 0.053 0.225 0.017 0.000 4.3000 0.053 0.231 0.017 0.000 4.4000 0.053 0.236 0.018 0.000 4.5000 0.053 0.241 0.020 0.000 4.6000 0.053 0.247 0.021 0.000 4.7000 0.053 0.252 0.022 0.000 4.8000 0.053 0.258 0.023 0.000 4.9000 0.053 0.263 0.023 0.000 5.0000 0.053 0.268 0.024 0.000 5.1000 0.053 0.274 0.025 0.000 5.2000 0.053 0.279 0.025 0.000 5.3000 0.053 0.284 0.026 0.000 5.4000 0.053 0.290 0.026 0.000 5.5000 0.053 0.295 0.027 0.000 5.6000 0.053 0.301 0.029 0.000 5.7000 0.053 0.306 0.031 0.000 5.8000 0.053 0.311 0.032 0.000 5.9000 0.053 0.317 0.033 0.000 6.0000 0.053 0.322 0.034 0.000 6.1000 0.053 0.327 0.035 0.000 6.2000 0.053 0.333 0.036 0.000 6.3000 0.053 0.338 0.037 0.000 6.4000 0.053 0.344 0.037 0.000 6.5000 0.053 0.349 0.038 0.000 6.6000 0.053 0.354 0.039 0.000 6.7000 0.053 0.360 0.039 0.000 6.8000 0.053 0.365 0.040 0.000 6.9000 0.053 0.370 0.041 0.000 7.0000 0.053 0.376 0.042 0.000 7.1000 0.053 0.381 0.042 0.000 7.2000 0.053 0.387 0.043 0.000 7.3000 0.053 0.392 0.043 0.000 7.4000 0.053 0.397 0.044 0.000 7.5000 0.053 0.403 0.045 0.000 7.6000 0.053 0.408 0.045 0.000 7.7000 0.053 0.414 0.046 0.000 7.8000 0.053 0.419 0.046 0.000 7.9000 0.053 0.424 0.047 0.000 8.0000 0.053 0.430 0.047 0.000 8.1000 0.053 0.435 0.381 0.000 8.2000 0.053 0.440 0.956 0.000 8.3000 0.053 0.446 1.559 0.000 8.4000 0.053 0.451 2.010 0.000 8.5000 0.053 0.457 2.253 0.000 8.6000 0.053 0.462 2.490 0.000 8.7000 0.053 0.467 2.686 0.000 8.8000 0.053 0.473 2.869 0.000 8.9000 0.053 0.478 3.040 0.000 9.0000 0.053 0.483 3.202 0.000 9.1000 0.053 0.489 3.356 0.000 9.2000 0.000 0.000 3.504 0.000 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:24 AM Page 9 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:1.296 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.481 Total Impervious Area:0.815 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.038103 5 year 0.059843 10 year 0.072163 25 year 0.085215 50 year 0.093292 100 year 0.100162 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.027232 5 year 0.036131 10 year 0.042673 25 year 0.051707 50 year 0.059016 100 year 0.066841 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.037 0.027 1950 0.047 0.028 1951 0.084 0.048 1952 0.026 0.019 1953 0.021 0.023 1954 0.033 0.021 1955 0.052 0.024 1956 0.042 0.033 1957 0.034 0.026 1958 0.038 0.023 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 10 1959 0.032 0.022 1960 0.057 0.040 1961 0.032 0.033 1962 0.020 0.018 1963 0.027 0.023 1964 0.036 0.025 1965 0.026 0.031 1966 0.025 0.023 1967 0.052 0.028 1968 0.032 0.025 1969 0.032 0.023 1970 0.026 0.022 1971 0.028 0.027 1972 0.062 0.043 1973 0.028 0.029 1974 0.031 0.025 1975 0.042 0.027 1976 0.030 0.022 1977 0.004 0.022 1978 0.026 0.025 1979 0.016 0.023 1980 0.059 0.043 1981 0.024 0.024 1982 0.046 0.044 1983 0.041 0.023 1984 0.025 0.020 1985 0.015 0.022 1986 0.066 0.027 1987 0.058 0.037 1988 0.023 0.021 1989 0.015 0.020 1990 0.122 0.048 1991 0.074 0.040 1992 0.028 0.025 1993 0.030 0.018 1994 0.010 0.017 1995 0.042 0.028 1996 0.089 0.047 1997 0.075 0.054 1998 0.017 0.023 1999 0.070 0.042 2000 0.029 0.024 2001 0.005 0.023 2002 0.032 0.032 2003 0.041 0.024 2004 0.053 0.046 2005 0.038 0.024 2006 0.045 0.032 2007 0.091 0.072 2008 0.117 0.048 2009 0.057 0.032 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.1221 0.0720 2 0.1170 0.0536 3 0.0907 0.0483 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 11 4 0.0893 0.0482 5 0.0839 0.0478 6 0.0746 0.0473 7 0.0735 0.0464 8 0.0700 0.0436 9 0.0660 0.0434 10 0.0625 0.0430 11 0.0592 0.0417 12 0.0584 0.0402 13 0.0574 0.0401 14 0.0567 0.0367 15 0.0533 0.0330 16 0.0524 0.0328 17 0.0518 0.0324 18 0.0467 0.0321 19 0.0455 0.0318 20 0.0451 0.0305 21 0.0424 0.0288 22 0.0417 0.0283 23 0.0417 0.0278 24 0.0412 0.0277 25 0.0408 0.0272 26 0.0383 0.0267 27 0.0379 0.0267 28 0.0374 0.0265 29 0.0360 0.0260 30 0.0336 0.0254 31 0.0328 0.0254 32 0.0325 0.0251 33 0.0323 0.0246 34 0.0323 0.0245 35 0.0320 0.0244 36 0.0316 0.0243 37 0.0308 0.0242 38 0.0302 0.0239 39 0.0295 0.0236 40 0.0295 0.0234 41 0.0284 0.0234 42 0.0284 0.0233 43 0.0279 0.0231 44 0.0273 0.0230 45 0.0265 0.0229 46 0.0264 0.0226 47 0.0261 0.0226 48 0.0258 0.0225 49 0.0252 0.0224 50 0.0248 0.0223 51 0.0237 0.0223 52 0.0231 0.0218 53 0.0214 0.0217 54 0.0199 0.0215 55 0.0169 0.0213 56 0.0160 0.0201 57 0.0150 0.0197 58 0.0149 0.0189 59 0.0099 0.0178 60 0.0053 0.0176 61 0.0036 0.0170 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 12 Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 13 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0191 17554 16273 92 Pass 0.0198 16164 14784 91 Pass 0.0206 14964 13631 91 Pass 0.0213 13851 12399 89 Pass 0.0221 12812 11302 88 Pass 0.0228 11809 10226 86 Pass 0.0236 10898 9251 84 Pass 0.0243 10119 8256 81 Pass 0.0251 9383 7364 78 Pass 0.0258 8729 6464 74 Pass 0.0266 8143 5529 67 Pass 0.0273 7593 4725 62 Pass 0.0281 7058 4323 61 Pass 0.0288 6588 4079 61 Pass 0.0296 6145 3912 63 Pass 0.0303 5775 3720 64 Pass 0.0310 5435 3542 65 Pass 0.0318 5103 3358 65 Pass 0.0325 4808 3193 66 Pass 0.0333 4528 3024 66 Pass 0.0340 4254 2817 66 Pass 0.0348 4017 2597 64 Pass 0.0355 3784 2344 61 Pass 0.0363 3551 2156 60 Pass 0.0370 3339 1980 59 Pass 0.0378 3138 1777 56 Pass 0.0385 2954 1580 53 Pass 0.0393 2787 1385 49 Pass 0.0400 2599 1210 46 Pass 0.0408 2449 1017 41 Pass 0.0415 2306 780 33 Pass 0.0423 2162 590 27 Pass 0.0430 2026 452 22 Pass 0.0438 1899 379 19 Pass 0.0445 1790 321 17 Pass 0.0453 1688 270 15 Pass 0.0460 1586 225 14 Pass 0.0468 1483 180 12 Pass 0.0475 1381 150 10 Pass 0.0483 1292 133 10 Pass 0.0490 1220 95 7 Pass 0.0498 1155 64 5 Pass 0.0505 1098 52 4 Pass 0.0513 1048 47 4 Pass 0.0520 997 40 4 Pass 0.0528 930 33 3 Pass 0.0535 883 30 3 Pass 0.0543 837 28 3 Pass 0.0550 789 26 3 Pass 0.0558 743 23 3 Pass 0.0565 713 22 3 Pass 0.0573 668 20 2 Pass 0.0580 630 17 2 Pass Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 14 0.0588 596 16 2 Pass 0.0595 565 14 2 Pass 0.0603 539 13 2 Pass 0.0610 497 12 2 Pass 0.0618 473 10 2 Pass 0.0625 434 9 2 Pass 0.0633 399 7 1 Pass 0.0640 366 7 1 Pass 0.0648 348 7 2 Pass 0.0655 323 6 1 Pass 0.0663 296 6 2 Pass 0.0670 272 6 2 Pass 0.0678 256 5 1 Pass 0.0685 235 5 2 Pass 0.0693 217 4 1 Pass 0.0700 195 4 2 Pass 0.0708 180 2 1 Pass 0.0715 158 2 1 Pass 0.0723 145 0 0 Pass 0.0730 129 0 0 Pass 0.0738 119 0 0 Pass 0.0745 109 0 0 Pass 0.0753 97 0 0 Pass 0.0760 91 0 0 Pass 0.0768 82 0 0 Pass 0.0775 76 0 0 Pass 0.0783 69 0 0 Pass 0.0790 61 0 0 Pass 0.0798 54 0 0 Pass 0.0805 48 0 0 Pass 0.0813 41 0 0 Pass 0.0820 38 0 0 Pass 0.0828 33 0 0 Pass 0.0835 27 0 0 Pass 0.0843 22 0 0 Pass 0.0850 21 0 0 Pass 0.0858 20 0 0 Pass 0.0865 19 0 0 Pass 0.0873 17 0 0 Pass 0.0880 13 0 0 Pass 0.0888 12 0 0 Pass 0.0895 8 0 0 Pass 0.0903 4 0 0 Pass 0.0910 3 0 0 Pass 0.0918 3 0 0 Pass 0.0925 3 0 0 Pass 0.0933 3 0 0 Pass Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 15 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0.1103 acre-feet On-line facility target flow:0.125 cfs. Adjusted for 15 min:0.125 cfs. Off-line facility target flow:0.0701 cfs. Adjusted for 15 min:0.0701 cfs. Green's Short Plat Vault 6-18-19 6/19/2019 9:12:54 AM Page 16 LID Report Green's Short Plat Vault 6-18-19 6/19/2019 9:13:03 AM Page 17 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. Green's Short Plat Vault 6-18-19 6/19/2019 9:13:03 AM Page 18 Appendix Predeveloped Schematic Green's Short Plat Vault 6-18-19 6/19/2019 9:13:03 AM Page 19 Mitigated Schematic APPENDIX B MAINTENANCE and OPERATIONS MANUAL APPENDIX C PACIFIC ENGINEERING LLC – OFFSITE ANALYSIS RECEIVED01/11/2018 jdingPLANNING DIVISION APPENDIX D GEOTECHNICAL REPORT Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone 425.415.0551 ♦ Fax 425.415.0311 www.riley-group.com October 18, 2018 Steve Hickey Meridian Build Group 304 Alaskan Way South, Suite 301 Seattle, Washington 98104 Subject: Infiltration Testing and Subsurface Conditions Meridian Build Group Greens Landing 5008 Northeast 2nd Street Renton, Washington RGI Project No. 2018-213 Dear Mr. Hickey As requested, The Riley Group, Inc. (RGI) is pleased to provide the results of our recent infiltration testing and subsurface characterization services at the above-referenced Site (Figure 1). RGI conducted one small Pilot Infiltration Test (PIT) at the Site per City of Renton guidelines and completed several test pits at the site to document subsurface conditions. RGI completed infiltration testing at the Greens Landing site in 2017. The study included completing a PIT test on the southern portion of the property. The results of that study are presented in our report “Pilot Infiltration Testing and Subsurface Conditions, Greens Landing, 5008 Northeast 2nd Street, Renton Washington”, dated October 19, 2017. The current study was completed to address comments from the City of Renton Department of Community & Economic Development regarding site development. The City requested additional infiltration testing be completed in Tract A, located on the northern half of the site. Subsurface Conditions RGI oversaw the excavation of a test pit in the proposed infiltration test location in Tract A, as shown on Figure 2, to document subsurface conditions and determine the appropriate depth for the infiltration test. The excavation was done using a subcontracted mini-excavator. Soil conditions observed in test pit near the infiltration test location included approximately six- inches of topsoil, underlain by brown, medium dense silty sand with gravel to a depth of approximately 3 feet below grade. A gray, very dense silty sand with gravel, interpreted to be lodgment till was encountered at a depth of 3 feet below grade, the lodgment till was observed to the depth of the test pit, 11 feet below grade. No groundwater was encountered in test pit. Subsurface conditions observed in the test pit at the infiltration test location are presented on the infiltration test IT-2 log. Test pits TP-2 was completed on the southwest portion of the site were roof downspout infiltration trenches are proposed. Soil conditions in test pit TP-2 included 6 inches of topsoil, underlain by medium dense gray silty sand with gravel to a depth of approximately 4 feet below grade. Gray, very dense silty sand with gravel, interpreted to be lodgment till was encountered from 4 feet USGS, 2014, Renton, Washington 7.5-Minute Quadrangle Approximate Scale: 1"=1000' 0 500 1000 2000 N Site Vicinity Map Figure 1 10/2018 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Meridian Build Group Greens Landing RGI Project Number 2018-213 Date Drawn: Address: 5008 Northeast 2nd Street, Renton, Washington 98059 SITE TP-1 IT-1 IT-2 TP-2 N Geotechnical Exploration Plan Figure 2 Approximate Scale: 1"=50' 0 25 50 100 = Test pit location by RGI, 10/09/18 = Infiltration test location by RGI, 10/09/18 = Test pit location by RGI, 10/09/17 = Infiltration test location by RGI, 10/09/17 = Site boundary 10/2018 Corporate Office 17522 Bothell Way Northeast Bothell, Washington 98011 Phone: 425.415.0551 Fax: 425.415.0311 Meridian Build Group Greens Landing RGI Project Number 2018-213 Date Drawn: Address: 5008 Northeast 2nd Street, Renton, Washington 98059 Project Name:Meridian Build Group Greens Landing Project Number:2018-213 Client:Meridian Build Group, LLC Test Pit No.: IT-2 Date(s) Excavated:10/09/18 Excavation Method:Excavation Excavator Type: Groundwater Level: Test Pit Backfill:Native Soil Logged By LC Bucket Size:n/a Excavating Contractor:Kelly's Excavating Sampling Me hod(s)Grab Location 5008 Northeast 2nd Street, Renton, Washington 98059 Surface Conditions:Sod Total Depth of Excavation:11 feet bgs Approximate Surface Elevation n/a Compaction Method n/a USCS SymbolTop soil SM SM REMARKS AND OTHER TESTSGraphic LogMATERIAL DESCRIPTION Top soil Brown, silty, gravelly SAND, medium dense, moist Infiltration test IT-2 Gray, silty SAND with gravel (lodgment till), very dense, moist Test pit excavated to 11 feet bgs No groundwater encounteredPID Reading, ppmDepth (feet)0 5 10 15 Sample IDSample TypeElevation (feet)Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name:Greens Landing Project Number:2017-207 Client:Norm & Cynthia Green Test Pit No.: TP-1 Date(s) Excavated:10/09/17 Excavation Method:Excavation Excavator Type:Excavator Groundwater Level:Not encountered Test Pit Backfill:Native Soil Logged By LC Bucket Size:n/a Excavating Contractor:Ryatt Construction Sampling Me hod(s)Grab Location 5008 Northeast 2nd Street, Renton, Washington 98059 Surface Conditions:Top Soil Total Depth of Excavation:8 feet bgs Approximate Surface Elevation n/a Compaction Method n/a USCS SymbolSoil SM SM SM REMARKS AND OTHER TESTSGraphic LogMATERIAL DESCRIPTION Top Soil Brown, silty SAND with wood chunks and clay pipe fragments (fill) Light brown, silty SAND with gravel and some cobbles, medium dense, moist Brown, silty SAND with gravel, medium dense, moist Test pit excavated to 8 feet bgsPID Reading, ppmDepth (feet)0 5 10 15 Sample IDSample TypeElevation (feet)Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name:Meridian Build Group Greens Landing Project Number:2018-213 Client:Meridian Build Group, LLC Test Pit No.: TP-2 Date(s) Excavated:10/09/18 Excavation Method:Excavation Excavator Type: Groundwater Level: Test Pit Backfill:Native Soil Logged By LC Bucket Size:n/a Excavating Contractor:Kelly's Excavating Sampling Me hod(s)Grab Location 5008 Northeast 2nd Street, Renton, Washington 98059 Surface Conditions:Sod Total Depth of Excavation:7 feet bgs Approximate Surface Elevation n/a Compaction Method n/a USCS SymbolTop soil SM SM REMARKS AND OTHER TESTSGraphic LogMATERIAL DESCRIPTION Top soil Brown, silty SAND with some gravel, medium dense, moist Gray, silty SAND with gravel (lodgment till), very dense, moist Test pit excavated to 7 feet bgs No groundwater encounteredPID Reading, ppmDepth (feet)0 5 10 15 Sample IDSample TypeElevation (feet)Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 Project Name:Meridian Build Group Greens Landing Project Number:2018-213 Client:Meridian Build Group, LLC Key to Logs USCS SymbolREMARKS AND OTHER TESTSGraphic LogMATERIAL DESCRIPTIONPID Reading, ppmDepth (feet)Sample IDSample TypeElevation (feet)1 2 3 4 5 6 7 8 9 COLUMN DESCRIPTIONS 1 Elevation (feet): Elevation (MSL, feet). 2 Depth (feet): Depth in feet below the ground surface. 3 PID Reading, ppm: The reading from a photo-ionization detector, in parts per million. 4 Sample Type: Type of soil sample collected at the depth interval shown. 5 Sample ID: Sample identification number. 6 USCS Symbol: USCS symbol of the subsurface material. 7 Graphic Log: Graphic depiction of the subsurface material encountered. 8 MATERIAL DESCRIPTION: Description of material encountered. May include consistency, moisture, color, and other descriptive text. 9 REMARKS AND OTHER TESTS: Comments and observations regarding drilling or sampling made by driller or field personnel. FIELD AND LABORATORY TEST ABBREVIATIONS CHEM: Chemical tests to assess corrosivity COMP: Compaction test CONS: One-dimensional consolidation test LL: Liquid Limit, percent PI: Plasticity Index, percent SA: Sieve analysis (percent passing No. 200 Sieve) UC: Unconfined compressive strength test, Qu, in ksf WA: Wash sieve (percent passing No. 200 Sieve) MATERIAL GRAPHIC SYMBOLS Silty SAND (SM) TYPICAL SAMPLER GRAPHIC SYMBOLS Auger sampler Bulk Sample 3-inch-OD California w/ brass rings CME Sampler Grab Sample 2.5-inch-OD Modified California w/ brass liners Pitcher Sample 2-inch-OD unlined split spoon (SPT) She by Tube (Thin-walled, fixed head) OTHER GRAPHIC SYMBOLS Water level (at time of drilling, ATD) Water level (after waiting) Minor change in material properties within a stratum Inferred/gradational contact between strata ?Queried contact between strata GENERAL NOTES 1: Soil classifications are based on the Unified Soil Classification System. Descriptions and stratum lines are interpretive, and actual lithologic changes may be gradual. Field descrip ions may have been modified to reflect results of lab tests. 2: Descriptions on these logs apply only at the specific boring locations and at the time the borings were advanced. They are not warranted to be representative of subsurface conditions at other loca ions or times. Sheet 1 of 1 The Riley Group, Inc. 17522 Bothell Way NE, Bothell, WA 98011 APPENDIX E BOND QUANTITY WORKSHEET 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 4 320.00 Catch Basin Protection ESC-3 35.50$ Each 14 497.00 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 665 997.50 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 1900 1,520.00 Interceptor Swale / Dike ESC-12 1.00$ LF 225 225.00 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 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:6,664.50 SALES TAX @ 10%666.45 EROSION/SEDIMENT TOTAL:7,330.95 (A) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR EROSION & SEDIMENT CONTROL Description No. (A) WRITE-IN-ITEMS Page 1 of 1 Ref 8-H Bond Quantity Worksheet SECTION II.a EROSION_CONTROL Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 0.25 2,500.00 1 10,000.00 Excavation - bulk GI-7 2.00$ CY 27 54.00 57 114.00 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:6,610.00 4,363.36 16,164.00 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR STREET AND SITE IMPROVEMENTS Quantity Remaining (Bond Reduction) (B)(C) Page 1 of 3 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 450 5,625.00 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 640 1,184.00 Sawcut, concrete, per 1" depth RI-13 3.00$ LF Sealant, asphalt RI-14 2.00$ LF 640 1,280.00 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 809 14,562.00 HMA Road, 2", 4" rock, First 2500 SY RI-27 28.00$ SY 1080 30,240.00 170 4,760.00 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 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 SUBTOTAL THIS PAGE:17,026.00 52,965.00 4,760.00 (B)(C)(D)(E) Page 2 of 3 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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$ EA 7 2,450.00 Median Landscaping LA-2 Right-of-Way Landscaping LA-3 Wetland Landscaping LA-4 SUBTOTAL LANDSCAPING & VEGETATION:2,450.00 (B)(C)(D)(E) TRAFFIC & LIGHTING No. Signs TR-1 Street Light System ( # of Poles)TR-2 2,000.00$ EA 5 10,000.00 Traffic Signal TR-3 Traffic Signal Modification TR-4 SUBTOTAL TRAFFIC & LIGHTING:10,000.00 (B)(C)(D)(E) WRITE-IN-ITEMS SUBTOTAL WRITE-IN ITEMS: STREET AND SITE IMPROVEMENTS SUBTOTAL:23,636.00 69,778.36 20,924.00 SALES TAX @ 10%2,363.60 6,977.84 2,092.40 STREET AND SITE IMPROVEMENTS TOTAL:25,999.60 76,756.20 23,016.40 (B)(C)(D)(E) Page 3 of 3 Ref 8-H Bond Quantity Worksheet SECTION II.b TRANSPORTATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 CB Type I D-4 1,500.00$ Each 3 4,500.00 2 3,000.00 CB Type IL D-5 1,750.00$ Each CB Type II, 48" diameter D-6 2,300.00$ Each 3 6,900.00 for additional depth over 4' D-7 480.00$ FT 6 2,880.00 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 4 680.00 Cleanout, PVC, 8"D-22 200.00$ Each Culvert, PVC, 4" D-23 10.00$ LF Culvert, PVC, 6" D-24 13.00$ LF 254 3,302.00 Culvert, PVC, 8" D-25 15.00$ LF Culvert, PVC, 12" D-26 23.00$ LF 630 14,490.00 60 1,380.00 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:28,770.00 8,362.00 (B)(C)(D)(E) Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Page 1 of 5 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES 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 Culvert, LCPE, 12"D-61 84.00$ LF 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: (B)(C)(D)(E) Page 2 of 5 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES 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 3 of 5 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES 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 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 (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 1,250.00$ Each 6 7,500.00 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:7,500.00 (B)(C)(D)(E) Page 4 of 5 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 Quantity Remaining (Bond Reduction) (B)(C) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES WRITE-IN-ITEMS (INCLUDE ON-SITE BMPs) Combined Detention/Water Quality Vault WI-1 75,000.00$ LS 1 75,000.00 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:75,000.00 DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:104,920.00 15,862.00 SALES TAX @ 10%10,492.00 1,586.20 DRAINAGE AND STORMWATER FACILITIES TOTAL:115,412.00 17,448.20 (B)(C)(D)(E) Page 5 of 5 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 1 of 1 Ref 8-H Bond Quantity Worksheet SECTION II.d WATER Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 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 260 24,700.00 181 17,195.00 Sewer Pipe, PVC, 8 inch Diameter SS-7 105.00$ LF 176 18,480.00 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 2 12,000.00 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:55,180.00 17,195.00 SALES TAX @ 10%5,518.00 1,719.50 SANITARY SEWER TOTAL:60,698.00 18,914.50 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR SANITARY SEWER Quantity Remaining (Bond Reduction) (B)(C) Page 1 of 1 Ref 8-H Bond Quantity Worksheet SECTION II.e SANITARY SEWER Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 Planning Division |1055 South Grady Way – 6 th 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)86,697.60$ Future Public Improvements Subtotal (c)76,756.20$ Stormwater & Drainage Facilities (Public & Private) Subtotal (d)(d)132,860.20$ (e) (f) Site Restoration Civil Construction Permit Maintenance Bond 59,262.80$ Bond Reduction 2 Construction Permit Bond Amount 3 Minimum Bond Amount is $10,000.00 1 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering. 2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% will cover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering. * Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton. ** Note: All prices include labor, equipment, materials, overhead and profit. EST1 ((b) + (c) + (d)) x 20% -$ MAINTENANCE BOND */** (after final acceptance of construction) 7,330.95$ 86,697.60$ 262,906.60$ 7,330.95$ -$ 132,860.20$ -$ 270,237.55$ P (a) x 100% SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS 12/20/2018 Keith Litchfield 29476 Litchfield Engineering 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) 425-821-5038 ka.litchfield@frontier.com Green's Landing Short Plat 18-000024 5008 NE 2nd Street 1523059219 FOR APPROVAL 12840 81st Ave NE, Kirkland, WA Page 1 of 1 Ref 8-H Bond Quantity Worksheet SECTION III. BOND WORKSHEET Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/20/2018 APPENDIX F 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 Pacific Crest Realty Advisors, LLC See attached Exhibit C. 1523059219 C1900406 R-4060 C1900406 4 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 NE 2ND ST.HOQUIAM AVE. NETR. A LOT 6 LOT 2 LOT 3 LOT 1 LOT 4 LOT 5 TR. B 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 PERMEABLE PAVEMENT (NON-VEGETATED) Your property contains an on-site BMP (best management practice) called “permeable pavement,” which was installed to minimize the stormwater quantity and quality impacts of some or all of the paved surfaces on your property. Permeable pavements reduce the amount of rainfall that becomes runoff by allowing water to seep through the pavement into a free-draining gravel or sand bed, where it can be infiltrated into the ground. This on-site BMP shall be maintained per Appendix A of the City of Renton’s Surface Water Design Manual. Permeable Pavements The type(s) of permeable pavement used on your property is (CHECK THE BOX(ES) THAT APPLY):  Porous concrete  Porous asphalt  Permeable pavers  Modular grid pavement MAINTENANCE RESTRICTIONS The area covered by permeable pavement as depicted by the site plan and design details must be maintained as permeable pavement 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 • Permeable pavements must be inspected after one major storm each year to make sure it is working properly. More frequent inspection is recommended. • Prolonged ponding or standing water on the pavement surface is a sign that the system is defective and may need to be replaced. If this occurs, contact the pavement installer or the City of Renton for further instructions. • A typical permeable pavement system has a life expectancy of approximately 25 years. To help extend the useful life of the system, the surface of the permeable pavement should be kept clean, stable and free of leaves, debris, and sediment through regular sweeping or vacuum sweeping. Aggregate fill in modular grid pavement may need periodic surface replenishment. • The owner is responsible for the repair of all ruts, deformation, and/or broken paving grids or pavers. • Modular grid pavement and permeable pavers filled with gravel or with gravel in the joints may need to be refilled periodically. RECORDING REQUIREMENT These permeable pavement 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 LIMITED INFILTRATION Your property contains an on-site BMP (best management practice) called “limited infiltration,” which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces on your property. Limited infiltration is a method of soaking runoff from impervious area (such as paved areas and roofs) into the ground. Infiltration devices, such as gravel filled trenches, drywells, and ground surface depressions, facilitate this process by putting runoff in direct contact with the soil and holding the runoff long enough to soak most of it into the ground. To be successful, the soil condition around the infiltration device 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. Infiltration Devices The infiltration devices used on your property include the following as indicated on the site plan (CHECK THE BOX(ES) THAT APPLY):  gravel filled trenches,  drywells 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 condition around the infiltration device must be able to soak water into the ground for a reasonable number of years. • Infiltration devices must be inspected annually and after major storm events to identify and repair any physical defects. • Maintenance and operation of the system should focus on ensuring the system's viability by preventing sediment-laden flows from entering the device. Excessive sedimentation will result in a plugged or non-functioning facility. • If the infiltration device has a catch basin, sediment accumulation must be removed on a yearly basis or more frequently if necessary. • Prolonged ponding around or atop a device may indicate a plugged facility. If the device becomes plugged, it must be replaced. • Keeping the areas that drain to infiltration devices well swept and clean will enhance the longevity of these devices. • For roofs, frequent cleaning of gutters will reduce sediment loads to these devices. x RECORDING REQUIREMENT These limited infiltration 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. INFILTRATION TRENCH AND DRYWELL SYSTEMS 6 24" 12" 24" WASHED ROCK 1 12"- 3" LEVEL INFILTRATION TRENCH SECTION A NTS PLAN VIEW NTS SECTION VIEW NTS VARIES A A 6" 6" 4" RIGID OR 6" FLEXIBLE PERFORATED PIPE CB SUMP w/SOLID LID ROOF DRAIN 4" RIGID OR 6" FLEXIBLE PERFORATED PIPE OVERFLOW SPLASH BLOCK ROOF DRAIN CB SUMP w/SOLID LID 12" FINE MESH SCREEN SETBACK FROM BUILDING 5' MIN. 1' MIN. 1' MIN. FILTER FABRIC COMPACTED BACKFILL 4" RIGID OR 6" FLEXIBLE PERFORATED PIPE 112" - 34" WASHED ROCK MIN. 1' ABOVE SEASONAL HIGH GROUNDWATER TABLE, SEE SECTION C.2.2.2 TRENCH SETBACK FROM BUILDING AS REQUIRED, 15' MIN. DRIVEWAY X-SECTION NTS 2' MIN. FILTER STR P SEE SECTIONS 6 3.4 & 6.3 5 18" M N. 6" MIN. 3/4" TO 1-1/2" WASHED DRA N ROCK GRASS OVERFLOW NOTE SEE C 2 2.3 FOR TRENCH LENGTHS, TRENCH SPACING AND SITE LIMITATIONS M N. 1' ABOVE SEASONAL HIGH GROUNDWATER TABLE, SEE SECTION C.2 2 2 X-SECTION NTS GRASS 2' MIN. 18" MIN. 6" MIN. 3/4" TO 1-1/2" WASHED DRAIN ROCK OVERFLOW 15' MIN. AS REQUIRED, SEE C.2.2.3 FROM ROOF N S T T S MIN. 1' ABOVE SEASONAL HIGH GROUNDWATER TABLE, SEE SECTION C.2.2.2 HOUSE FLOW 48 INCH DIAMETER HOLE FILLED WITH 1 12" - 3" WASHED DRAIN ROCK SECTION NTS MARK CENTER OF HOLE WITH 1" CAPPED PVC OR OTHER MEANS FLUSH WITH SURFACE ROOF DOWNSPOUT OVERFLOW SPLASH BLOCK TOPSOIL FINE MESH SCREEN MIN. 4" DIA. PVC PIPE SIDES OF HOLE LINED WITH FILTER FABRIC CATCH BASIN (YARD DRAIN) 15' MIN. AS REQUIRED, SEE SECTION C.2.2.3 VARIES 1' MIN. MIN. 1' ABOVE SEASONAL HIGH GROUNDWATER TABLE, SEE SECTION C.2.2.2 5' MIN. SETBACK FROM BUILDING FLOW PLAN VIEW NTS HOUSE ROOF DOWNSPOUT ROOF DOWNSPOUT CATCH BASIN (YARD DRAIN) 8 INCH DIAMETER HOLE FILLED WITH 1 2 - 3 WASHED DRAIN ROCK 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 bs 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 bs. 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 bs 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. Exhibit C – Legal Description THE EAST 35 FEET OF LOT 3 AND ALL OF LOT 4, KING COUNTY SHORT PLAT NO. 881050, AS RECORDED JANUARY 22, 1982 UNDER RECORDING NO. 8201220536, RECORDS OF KING COUNTY, WASHINGTON. TOGETHER WITH THE EAST 30 FEET OF THE SOUTH HALF OF THE SOUTHWEST QUARTER OF THE NORTHWEST QUARTER OF THE NORTHEAST QUARTER OF SECTION 15, TOWNSHIP 23 NORTH, RANGE 5 EAST, W.M., IN KING COUNTY, WASHINGTON. APPENDIX G FLOW CONTROL & WATER QUALITY FACILITY SUMMARY SHEET & SKETCH 2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D 4/24/2016 Page 1 STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________ (provide one Stormwater Facility Summary Sheet per Natural Discharge Location)Date ___________________ OVERVIEW:NPDES Permit No.___________________ Project Name Parcel No.____________________________ Project Location Retired Parcel No.____________________________ Downstream Drainage Basins:Project includes Landscape Management Plan?yes Major Basin Name ______________________________________________(include copy with TIR as Appendix)no Immediate Basin Name ______________________________________________ GENERAL FACILITY INFORMATION: Leachable Metals Infiltration Impervious Surface Limit Type # of Type # of Type # of facilities Flow Control BMPs Ponds ______ Ponds ______ Ponds ______ Basic Clearing Limit Vaults ______ Tanks ______ Vaults ______ Conservation Drainage Facility Tanks ______ Trenches _____ Tanks ______ Flood Problem Landscape Management Plan If no flow control facility, check one: Project qualifies for KCSWDM Exemption (KCSWDM 1.2.3): Basic Exemption (Applies to Commercial parcels only)Area % of Total Redevelopment projects Cost Exemption for Parcel Redevelopment projects Direct Discharge Exemption Other _____________________ Total impervious surface served by Project qualifies for 0.1 cfs Exception per KCSWDM 1.2.3 flow control facility(ies) (sq ft) Impervious surface served by flow KCSWDM Adjustment No. ___________________control facility(ies) designed 1990 or later (sq ft) approved KCSWDM Adjustment No. __________________ Impervious surface served by Shared Facility Name/Location: _________________________ pervious surface absorption (sq ft) No flow control required (other, provide justification): Impervious surface served by approved ____________________________________________________ water quality facility(ies) (sq ft) Flow Control Performance Std Declarations of Covenant Recording No. Water QualityDetention TREATMENT SUMMARY FOR TOTAL IMPERVIOUS SURFACES ----- Total Impervious Acreage (ac) No flow control required per approved Flow control provided in regional/shared facility per approved PROVIDE FACILITY DETAILS AND FACILITY SKETCH FOR EACH FACILITY ON REVERSE. USE ADDITIONAL SHEETS AS NEEDED FOR ADDITIONAL FACILITIES Impervious Surface Exemption for Transportation Total Acreage (ac) 2016 KING COUNTY SURFACE WATER DESIGN MANUAL, REFERENCE D 4/24/2016 Page 2 STORMWATER FACILITY SUMMARY SHEET DPER Permit No.___________________ (provide one Stormwater Facility Summary Sheet per Natural Discharge Location) Project Name Downstream Drainage Basins: Major Basin Name _______________________________ Project Location Immediate Basin Name ___________________________ FLOW CONTROL FACILITY:Basin: Facility Name/Number _______________________________________ New Facility Project Impervious Facility Location ____________________________________________ Existing Facility Acres Served ________ UIC? □ yes □ no UIC Site ID:% of Total Project Impervious cu.ft.Volume Factor Acres Served ________ _____________ ac.ft.____________of Safety _______No. of Lots Served ________ Control Structure location: _______________________________________________ Type of Control Structure:No. of Orifices/Restrictions __________ Riser in vault Size of Orifice/Restriction (in.) No.1 ______ cu.ft. Riser in Type II CB (numbered starting with lowest No.2 ______ ac.ft. Weir in Type II CB orifice): No.3 ______ (inches in decimal format)No.4 ______ WATER QUALITY FACILITIES Design Information Indicate no. of water quality facilities/BMPs for each type:Water Quality design flow (cfs) _______Flow dispersion Water Quality treated volume (sandfilter) (cu.ft.) _______Filter strip Water Quality storage volume (wetpool) (cu.ft.) _______Biofiltration swale regular, wet or Landscape management plan Farm management plan continuous inflow _______Wetvault combined w/detention ______High flow bypass structure (e.g., flow-splitter catch basin) _______Wetpond basic large combined w/detention ______Oil/water separator baffle coalescing plate _______Pre-settling pond ______Storm filter _______Stormwater wetland ______Pre-settling structure (Manufacturer:______________________) _______Sand filter basic large Sand bed depth ______Catch basin inserts (Manufacturer:________________________) regular linear vault (inches)______________Source controls _________________________________________ ● Is facility lined? yes no If so, what marker is used above liner?_____________________________________________________ Facility Summary Sheet Sketch: All detention, infiltration and water quality facilities must include a detailed sketch (11"x17" reduced size plan sheets preferred). Dam Safety Regulations (WA State Dept of Ecology): Reservoir Volume above natural grade Depth of Reservoir above natural grade (ft) Live Storage Volume Live Storage Depth (ft) ³´29476 0' 0& 564''6)4''05 .#0&+0) 5*146 2.#6 )4''05 .#0&+0) 5*146 2.#6 )4''05 .#0&+0) 5*146 2.#6 .7# Ä%-4060-4060 7DETENTION/ WATER QUALITY VAULTDETAILS & STORM DRAIN NOTES0GRAPHIC SCALE105 10SCALE IN FEET1"=10'7 TED-40 R 07 WTR-27-4060 W-406002