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HomeMy WebLinkAboutTIR-4181 Western Washington Division Eastern Washington Division 165 NE Juniper St., Ste 201, Issaquah, WA 98027 407 Swiftwater Blvd, Cle Elum, WA 98922 Phone: (425) 392-0250 Fax: (425) 391-3055 Phone: (509) 674-7433 Fax: (509) 674-7419 www.EncompassES.net TECHNICAL INFORMATION REPORT For Mangat Short Plat 1415 N 24th St Renton, WA 98056 April 2, 2021 Revised 9/13/2021 9/13/2021 Prepared by: Samuel Salo Encompass Engineering Job No. 20547 Prepared For: Sukhjinder Mangat 10623 SE 279th Street Kent, WA 98030 Scott Warlick 9/27/2021 SURFACE WATER UTILITY krevans 09/27/2021 Mangat Short Plat Technical Information Report 9/13/2021 P a g e | i Table of Contents I. PROJECT OVERVIEW ................................................................................................................ 1 II. CONDITIONS AND REQUIREMENTS SUMMARY ...................................................................... 7 III. OFFSITE ANALYSIS .................................................................................................................. 12 IV. FLOW CONTROL, LOW IMPACT DEVELOPMENT AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ........................................................................................................................... 19 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ..................................................................... 23 VI. SPECIAL REPORTS AND STUDIES ............................................................................................ 23 VII. OTHER PERMITS ..................................................................................................................... 23 VIII. CSWPP ANALYSIS AND DESIGN .............................................................................................. 23 IX. BOND QUANTITIES, FACILITY SUMMARIES AND DECLARATION of COVENANT ................... 23 X. OPERATION AND MAINTENANCE MANUAL .......................................................................... 23 List of Figures Figure 1 – TIR Worksheet Figure 2 – Vicinity Map Figure 3 – Soils Map and Legend Figure 4 – Existing Conditions Map Figure 5 – Developed Conditions Map Figure 6 – Drainage Review Flow Chart Figure 7 – Downstream Map Appendix A Limited Geotechnical Evaluation by Cobalt Geosciences dated August 20, 2020. Appendix B WWHM Output Appendix C Bond Quantity Worksheet Appendix D Declaration of Covenant Appendix E Operations and Maintenance Manual 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 __________________ __________________ __________________ Sukhjinder Mangat 253-236-6819 10623 SE 279th St Kent, WA 98030 Nicole Mecum, PE Encompass Engineering & Surveying 425-961-2168 Mangat Short Plat 23 N 5 E 5 1415 N 24th St, Renton, WA 98056 TBD 3/12/2021 3/12/2021 9/13/2021 9/13/2021 9/13/2021 9/13/2021 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 ______________________  _____________________________________ Wellhead protection, Zone 1 Modified 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: _________________________ Indianola Loamy Sand 5-15%Low Zone 2 Aquifer Protection Area Open conveyance systems may need liner East Lake Washington 2 12/6/2020 Basic Dispersion 2 TBD TBD 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: None 2-Lot Short Plat None 1 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 _______________________________ Basic Dispersion Lots 1 & 2 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 9/13/2021 Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 1 I. PROJECT OVERVIEW Project: Mangat Short Plat Site Address: 1415 N. 24th Street, Renton, WA 98056 (See Vicinity Map) Tax Parcel #: 334450-0234 Zoning District: R-6, Single Family Residential Site Area: 21,412 SF (0.49 Acres) Site Location: The site is in the City of Renton within the NW quarter of Section 5, Township 23 North, Range 5 East, W.M, King County, Washington. The site is located on the south side of N 24th St, west of the intersection of Meadow Ave. N and N 24th St. Figure 2: Vicinity Map Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 2 Pre-developed Site Conditions The project site is located in the City of Renton on a 21,412 SF (0.49 Acres) lot that is zoned R-6 (single-family residential). The site is accessed from N 24th St, east of the intersection of N 24th St and Meadow Ave N. The site is bordered to the east, west and south by single-family residences and to the north by City of Renton ROW. The site is currently developed with a single-family residence accessed from N 24th St via a concrete driveway at the northeast corner of the site. South of the residence, a grassy hill slopes off-site to the southwest at slopes of 4-8%. The property is located within the East Lake Washington drainage basin, however it has two separate discharge areas. Runoff from the northern portion of the existing site generally sheet flows towards N 24th St where it flows downhill to west and enters the City of Renton storm system through a type 1 catch basin. Runoff from the southern portion of the site sheet flows to the southwest towards an undeveloped forested hillside, before entering the Bella Vista Apartment complex storm system, where it converges with the stormwater from the northern discharge area at just under a ¼ mile from the project site. Stormwater is ultimately discharged to Lake Washington, located approximately ½ mile west of the site. See full downstream analysis in Section III of this Technical Information Report (TIR). An Existing Conditions Map is included as Figure 4 at the end of this Section. Critical Areas A Wellhead Protection Area, Zone 1 Modified and an Aquifer Protection Area, Zone 2 are mapped on the project site according to City of Renton Maps and the RSWDM Reference 15-B. No other critical areas have been identified on the project site. Soils Per the US Department of Agriculture (USDA), Natural Resources Conservation Service (NRCS) Web Soil Survey (WSS) information, the entire project site is underlain with Indianola loamy sand, 5 to 15 percent slopes (See Figure 3 on the following page). A Limited Geotechnical Evaluation prepared by Cobalt Geosciences (Appendix A) confirms this soil classification across the site, with the discovery of weathered and unweathered glacial till. An in-situ infiltration test was performed and an infiltration rate of 0.22 inches per hour was found which is unsuitable for stormwater infiltration. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 3 Figure 3: Soil Map and Legend Developed Site Conditions The project proposes the development of two (2) single-family lots within the 21,412 SF (0.49 AC) parcel, as well as an 11.5-foot right-of-way dedication with frontage improvements, and road widening at the intersection of Meadow Ave N and N 24th St for an emergency vehicle turnaround. Lot 1 is 10,277 SF (0.24 Acres) and is located along the eastern portion of the site with driveway access off of N 24th St. Lot 2 is 9,536 SF (0.22 Acres) and is located on the western portion of the site with driveway access off of N 24th St. Frontage improvements will include the addition of a 5-foot sidewalk, 8-foot planter strip, as well as curb and gutter along the edge of Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 4 asphalt roadway. At the intersection of N 24th St and Meadow Ave N, the existing asphalt roadway will be widened by approximately 7 feet to accommodate a hammerhead Emergency Vehicle Turnaround. The parcel is zoned R-6, which allows for a maximum building coverage of 40% and a maximum impervious surface coverage of 55%. The maximum allowable building/impervious surface for each lot is discussed below: · Lot 1: The maximum allowable building coverage for Lot 1 is 10,277 SF x 0.4 = 4,111 SF, and the maximum impervious surface coverage is 10,277 SF x 0.55 = 5,652 SF. The final site layout of Lot 1 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 1 will use the maximum coverages stated above. · Lot 2: The maximum allowable building coverage for Lot 2 is 9,536 SF x 0.4 = 3,814 SF, and the maximum impervious surface coverage is 9,536 SF x 0.55 = 5,245 SF. The final site layout of Lot 2 has not been determined at this stage; therefore, this report assumes that the future impervious surfaces required to construct the residence on Lot 2 will use the maximum coverages stated above. Stormwater runoff from the proposed development of Lots 1 and 2 will be managed as follows: · Lot 1: Stormwater BMP’s satisfying Core Requirement #9 will be used to the maximum extent feasible to mitigate new runoff created by the proposed single-family residence and other impervious surfaces on-site. A 50-foot basic dispersion trench with notched board and 25-foot native vegetated flowpath is proposed on Lot 1 south of the residence to mitigate stormwater from rooftop areas. This report assumes that 3,500 SF of rooftop area will be conveyed to this dispersion trench, the maximum allowed for its size. · Lot 2: Stormwater BMP’s satisfying Core Requirement #9 will be used to the maximum extent feasible to mitigate new runoff created by the proposed single family residence and other impervious surfaces on-site. A 50-foot basic dispersion trench with notched board and 25-foot native vegetated flowpath is proposed on Lot 1 south of the residence to mitigate stormwater from rooftop areas. This report assumes that 3,500 SF of rooftop area will be conveyed to this dispersion trench, the maximum allowed for its size. Please refer to Core Requirement # 9 in Section II and Section IV of this TIR for additional discussion on stormwater BMPs. A Developed Conditions Map is provided as Figure 5 at this end of this Section. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 5 Figure 4 – Existing Conditions Map Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 6 Figure 5 – Developed Conditions Map Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 7 II. CONDITIONS AND REQUIREMENTS SUMMARY The 2017 City of Renton Surface Water Design Manual (RSWDM) was utilized to determine and address all core and special requirements. Based on the criteria specified in Figure 1.1.2.A of the RSWDM, the project falls under Full Drainage Review. Per Section 1.1.2.4 of the RSWDM, the project must meet all nine (9) core and all six (6) special requirements. See Figure 6 below for more information on how the type of drainage review was determined. Figure 6: Drainage Review Flow Chart Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 8 Core Requirements Core Requirement #1: Discharge at the Natural Location The proposed development runoff will follow existing drainage patterns that flow to the north into N 24th St and the City of Renton storm system as well as southwest towards an undeveloped, forested hillside. Refer to the Level 1 Downstream Analysis in Section III of this TIR for a complete description of the existing drainage paths. Core Requirement #2: Downstream Analysis A Level 1 Downstream analysis has been completed for the site and no existing or potential problems have been identified. This analysis is included in Section III of this TIR. Core Requirement #3: Flow Control Facilities Based on the City of Renton’s flow control application map, the project site is located within the Peak Rate Flow Control Standard (Existing Site Conditions). Flow control facilities are required to match the developed peak discharge rates to existing site conditions peak discharge rates for 2-, 10- and 100-year return periods. The proposed stormwater BMPs result in a 0.0109 CFS decrease in the 100-year flow using 15-minutes time steps. This is below the allowable threshold of a 0.15 CFS maximum increase per Section 1.2.3.1.A of the RSWDM; therefore, the project meets flow control exemption 2. No formal flow control facilities are proposed at this time; however, flow control BMPs will be implemented as described in Core Requirement #9. Please refer to Section IV of this TIR for additional discussion. Core Requirement #4: Conveyance System See Section V of this TIR for Conveyance System Analysis. Core Requirement #5: Construction Stormwater Pollution Prevention The limits of construction for the project are less than 1 acre. A temporary erosion and sediment control (TESC) plan providing details on best management practices (BMPs) to be implemented during construction is included in the engineering plan set. A Construction Stormwater Pollution Prevention Plan (CSWPPP) has been prepared and included under separate cover. Core Requirement #6: Maintenance and Operations An Operation and Maintenance Manual is included in Appendix E of this TIR. Core Requirement #7: Financial Guarantees and Liability The owner will arrange for any financial guarantees and liabilities required by the permit. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 9 Core Requirement #8: Water Quality Facilities In accordance with Section 1.2.8.1.A of the RSWDM, Basic Water Quality Treatment is not required for this project as new plus replaced pollution generating impervious surfaces (PGIS) do not exceed 5,000 SF, meeting exemption 1. 1,949 SF of asphalt road repair and widening is proposed on N 24th St, 494 SF of concrete driveway is proposed within the ROW dedication area, and 750 SF of asphalt driveway is estimated within Lots 1 & 2 (at a 15-foot width). These quantities total to 3,193 SF of PGIS that will be created or replaced as a result of this project. Core Requirement #9: Flow Control BMPs This project is classified as a small subdivision; therefore, it is subject to the Small Subdivision Project BMP Requirements detailed in Section 1.2.9.3.1 in the RSWDM. Although implementation of individual lot BMPs is not required until building permit application, BMPs have been considered for the future improvements on Lots 1 and 2 based on Section 1.2.9.2 and of the RSWDM. See Section IV of this TIR for further discussion and flow control analysis. Impervious Surface BMPs Full Dispersion: Infeasible for Lots 1 and 2. · Lots 1 and 2: The space required for a 100-foot native vegetated flowpath segment is not available on these sites. Full Infiltration: Infeasible for Lots 1 and 2. · Lots 1 and 2: The Limited Geotechnical Evaluation prepared by Cobalt Geosciences dated August 20, 2020 (Appendix A) states that infiltration is infeasible at the site due to underlain glacial till and confirmed by an in-situ infiltration test. Limited Infiltration: Infeasible for Lots 1 & 2. · Lots 1 and 2: BMP’s relying on infiltration are not feasible as described above. Rain Gardens/Bioretention: Infeasible for Lots 1 and 2. · Lots 1 and 2: BMP’s relying on infiltration are not feasible as described above. Permeable Pavement: Infeasible for Lots 1 and 2. · Lots 1 and 2: BMP’s relying on infiltration are not feasible as described above. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 10 Basic Dispersion: Feasible for Lots 1 and 2 · Lot 1: A 50-foot Basic Dispersion trench with notched board and 25-foot native vegetated flowpath is proposed for Lot 1. The maximum area of 3,500 SF will be conveyed to this trench from the rooftop of the residence. · Lot 2: A 50-foot Basic Dispersion trench with notched board and 25-foot native vegetated flowpath is proposed for Lot 1. The maximum area of 3,500 SF will be conveyed to this trench from the rooftop of the residence. Reduced Impervious Surface Credit: Infeasible for Lots 1 and 2 · Lots 1 and 2: The maximum impervious surfaces assumed for Lots 1 and 2 of 5,652 SF and 5,245 SF respectively, exceed the threshold of 4,000 SF, which is required for eligibility for a reduced impervious surface credit. Native Growth Retention Credit: Infeasible for Lots 1 and 2 · Lots 1 and 2: The necessary area to allow for 3.5 SF of native vegetated surface for every SF of impervious surface is not available on either lot. Tree Retention Credit: Feasible for Lots 1 and 2 · Lots 1 and 2: At least 30% of significant trees will be retained per Department of Community and Economic Development notes in the Pre-Application Meeting. Soil Amendment: Feasible for Lots 1 and 2 · Lots 1 and 2: All disturbed, pervious areas of the project will meet soil amendment requirements as detailed in Section C.2.13 of the RSWDM. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 11 Special Requirements Special Requirement #1: Other Adopted Area-Specific Requirements Critical Drainage Area – N/A Master Drainage Plan – N/A Basin Plan – N/A Lake management Plan – N/A Shared Facility Drainage Plan – N/A Special Requirement #2: Flood Hazard Area Delineation The limits of this project do not lie within a delineated FEMA 100-year floodplain. Special Requirement #3: Flood Protection Facilities This project does not rely on or propose to modify/construct a new flood protection facility. Special Requirement #4: Source controls The project is a single-family residential development; therefore, this requirement is not applicable. Special Requirement #5: Oil Control This project is not considered high-use in need of oil control. Special Requirement #6: Aquifer Protection Area The site is located within Zone 2 of the City’s Aquifer Protection Area, and complies with the requirements listed in section 1.3.6 of the RSWDM. No flow control facilities or open conveyance systems are proposed on the site. Conditions of Approval 1. A demolition permit shall be obtained and all required inspections completed for the removal of the existing residence prior to the recording of the short plat. A demolition permit will be obtained and all inspections will be completed for the removal of the existing residence prior to the recording of the short plat. 2. A final detailed landscape plan shall be provided at the time of Civil Construction Permit review for re review and approval by the Current Planning Project Manager. Landscaping proposed within the public right-of-way shall be installed prior to the recording of the short plat, onsite landscaping shall be installed prior to final building inspection for the new homes to be constructed on the proposed lots. A final landscape plan has been prepared and submitted addressing this comment. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 12 3. A final tree retention plan shall be submitted at the time of Civil Construction Permit review for review and approval by the Current Planning Project Manager. A final tree retention plan has been prepared and submitted addressing this comment. III. DOWNSTREAM ANALYSIS A Level 1 Downstream analysis has been conducted per the requirements in Section 1.2.2.1 of the RSWDM. Please see Tasks 1 through 4 below for a summary of the results. Task 1: Define and Map the Study Area The area of analysis extends from the site discharge points along N 24th St and the southern limit of the site to approximately a quarter-mile downstream where the two discharge areas converge. A Downstream Map is provided in Figure 7 below. Figure 7: Downstream Map Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 13 Task 2: Review All Available Information on the Study Area Per King county resources, there have been no significant drainage complaints within a quarter- mile downstream of the site. Task 3: Field Inspect the Study Area A field inspection was performed by Encompass Engineering & Surveying on October 6, 2020. Please refer to Task 4 for a detailed description of the downstream drainage system and analysis. Task 4: Describe the Drainage System Runoff from the site is split into two Natural Discharge Areas (A & B), however these flowpaths converge within a ¼ mile downstream of the site, creating one Threshold Discharge Area for the site. Runoff from Discharge Area A sheet flows into N 24th St and flows to the west along the south side of the crowned roadway along the edge of pavement (A1). A raised asphalt bump directs the flow northwest towards a type 1 catch basin (A2) which conveys the stormwater north through an 8” CMP pipe on Garden Ct N. After approximately 100 LF, the stormwater enters another type 1 catch basin (A3) and flows west onto private property on parcel 0523059065. According to City of Renton Maps, the stormwater enters a type 2 CB (A4) on parcel 0523059065 and moves west through two type 1 CB’s and two type 2 CB’s via a 12” PVC stormwater main, before entering a type 2 CB (A5) in the Bella Vista Apartment Complex. From here, stormwater runs in a counterclockwise loop through a series of type 1 CB’s (A6) around the complex with stormwater main starting at 12” PVC and sizing up to 15” and then 18” PVC before entering a type 2 CB (A7) at the entrance of the apartment complex where it joins the stormwater from Discharge Area B (described below). This is where the analysis was completed, just over ¼ mile downstream of the site, but less than ¼ mile from Discharge Area B, the shorter of the two flowpaths. Please refer to Figure 7 above, for the approximate location of identified drainage features. Runoff from Discharge Area B sheet flows off-site to the southwest onto grass and forested areas (B1) on adjacent parcels 3344500235 & 3344500250. The slope increases to approximately 30% as runoff continues to sheet flow down the undeveloped, forested hillside until it reaches a depression (B2) behind three townhouse buildings in the Bella Vista Apartment complex. This low point runs to the south behind these units in an overgrown vegetated depression until it reaches a grass lawn area (B3) and sheet flows to the west onto a paved parking lot. A type 1 CB (B4) picks up this storm water and coveys it to the north via a 12” storm pipe into a Type 2 CB (B5) where it joins the stormwater from Discharge Area B at just under ¼ mile from the project site. Stormwater from both discharge areas continue through the City of Renton stormwater system and discharge into Lake Washington (A8/B6) at Coulon Beach Park at approximately a ½ mile from the project site. If conveyance system nuisance, severe erosion, severe flooding, or wetland hydrology problems are identified downstream of the site under Core Requirement #2, additional impact analysis and/or mitigation may be required. As discussed in Task 2, there have been no recent significant Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 14 drainage complaints within a quarter-mile downstream of the site. As no existing drainage or conveyance issues have been recently identified, further impact analysis and mitigation of the downstream stormwater system is not required. Please refer to the conveyance analysis in Section V of this TIR for additional discussion and evaluation of the on-site conveyance system capacity. Photographs from the site visit are included below. Element A1- Sheet flow on N 24th St at site frontage downhill to the West Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 15 Element A2- Type 1 CB with raised asphalt bump to direct stormwater Element A3- Type 1 CB conveying stormwater onto private property to the West Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 16 Element A5- Type 2 CB in Bella Vista Apartment Complex Element A6- Series of type 1 CB’s in counterclockwise loop around Bella Vista Complex Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 17 Element A7/B5- Type 2 CB (w/rectangular lid) where Discharge Area A & B converge Element B1- Sheet flow off-site to southwest onto undeveloped grass & forest Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 18 Element B2- Low point at bottom of hillside behind Bella Vista townhomes Element B3- Sheet flow down grass lawn towards asphalt parking area and Bella Vista storm system Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 19 Element A8/B6- Final Discharge into Lake Washington IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Part A: Existing Site Hydrology The 21,412 SF (0.49 AC) site is currently developed with a single-family residence accessed from N 24th St via a concrete driveway at the northeast corner of the site. South of the residence, a grassy hill slopes off-site to the southwest at slopes of 4-8%. The property is located within the East Lake Washington drainage basin, however it has two separate discharge areas. Runoff from the northern portion of the existing site generally sheet flows towards N 24th St where it flows downhill to west and enters the City of Renton storm system through a type 1 catch basin. Runoff from the southern portion of the site sheet flows to the southwest towards an undeveloped forested hillside, before entering the Bella Vista Apartment complex storm system, where it converges with the stormwater from the northern discharge area at just under a ¼ mile from the project site. Stormwater is ultimately discharged to Lake Washington, located approximately ½ mile west of the site. See full downstream analysis in Section III of this Technical Information Report (TIR). The Limited Geotechnical Evaluation prepared by Cobalt Geosciences (Appendix A) confirms the NRCS Indianola loamy sand soil classification on the site, and has determined infiltration to be infeasible. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 20 WWHM 2012 was used to model the existing condition within the 22,870 SF (0.53 AC) limits of disturbance using existing surfaces found on site including rooftop, driveway, lawn and walkways. Part B: Developed Site Hydrology The project proposes the development of two (2) single-family lots within the 21,412 SF (0.49 Acres) parcel, as well as an 11.5-foot right-of-way dedication with frontage improvements, and road widening at the intersection of Meadow Ave N and N 24th St for an emergency vehicle turnaround. Lot 1 is 10,277 SF (0.24 Acres) and is located along the eastern portion of the site with driveway access off of N 24th St. Lot 2 is 9,536 SF (0.22 Acres) and is located on the western portion of the site with driveway access off of N 24th St. Frontage improvements will include the addition of a 5-foot sidewalk, 8-foot planter strip, as well as curb and gutter along the edge of asphalt roadway. At the intersection of N 24th St and Meadow Ave N, the existing asphalt roadway will be widened by approximately 7 feet to accommodate a hammerhead Emergency Vehicle Turnaround. Stormwater runoff from the proposed development of Lots 1 and 2 will be managed as follows: · Lot 1: Stormwater BMP’s satisfying Core Requirement #9 will be used to the maximum extent feasible to mitigate new runoff created by the proposed single family residence and other impervious surfaces on-site. A 50-foot basic dispersion trench with notched board and 25-foot native vegetated flowpath is proposed on Lot 1 south of the residence to mitigate stormwater from rooftop areas. This report assumes that 3,500 SF of rooftop area will be conveyed to this dispersion trench, the maximum allowed for its size. · Lot 2: Stormwater BMP’s satisfying Core Requirement #9 will be used to the maximum extent feasible to mitigate new runoff created by the proposed single-family residence and other impervious surfaces on-site. A 50-foot basic dispersion trench with notched board and 25-foot native vegetated flowpath is proposed on Lot 1 south of the residence to mitigate stormwater from rooftop areas. This report assumes that 3,500 SF of rooftop area will be conveyed to this dispersion trench, the maximum allowed for its size. WWHM 2012 was used to model the proposed condition as follows: · Lot 1: The modeled limits of disturbance for Lot 1 is 10,277 SF. The maximum impervious surface per R-6 zoning of 5,652 SF was assumed with 3,500 SF of this area being conveyed to the Basic Dispersion trench. Per Table 1.2.9.A in the RSWDM, 90% of the area going to basic dispersion can be modeled as impervious, and 10% as lawn. The remaining 4,625 SF of pervious surface on Lot 1 will meet soil amendment requirement as detailed in Section C.2.13 of the RSWDM; therefore, it has been modeled as 100% pasture with moderate slopes in type C soils. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 21 · Lot 2: The modeled limits of disturbance for Lot 2 is 9,526 SF. The maximum impervious surface per R-6 zoning of 5,245 SF was assumed with 3,500 SF of this area being conveyed to the Basic Dispersion trench. Per Table 1.2.9.A in the RSWDM, 90% of the area going to basic dispersion can be modeled as impervious, and 10% as lawn. The remaining 4,291 SF of pervious surface on Lot 1 will meet soil amendment requirement as detailed in Section C.2.13 of the RSWDM; therefore, it has been modeled as 100% pasture with moderate slopes in type C soils. · ROW Dedication & Road Widening: The modeled limits of disturbance for the ROW dedication area and road widening is 3,829 SF. This will include 603 SF of sidewalk, 495 SF of driveway as well as 1,954 SF of asphalt road repair and widening. The remaining 777 SF of pervious surface will meet soil amendment requirement as detailed in Section C.2.13 of the RSWDM; therefore, it has been modeled as 100% pasture with moderate slopes in type C soils. Please refer to Core Requirement #9 in Section II of the TIR for additional discussion. A Developed Conditions Map is provided as Figure 5. A summary of the existing and developed analyses is provided in the table below: WWHM Model (Mitigated) Area Description Size Developed Condition ROW Dedication Sidewalk 603 SF (0.01 AC) Modeled as Sidewalk, Mod ROW Dedication Driveway 495 SF (0.01 AC) Modeled as Driveway, Mod WWHM Model (Pre-Developed) Area Description Size Existing Condition Rooftop 2,899 SF (0.07 AC) Modeled as Rooftops, Flat Driveway 1,009 SF (0.02 AC) Modeled as Driveways, Mod Walkways/Decks 808 SF (0.02 AC) Modeled as Sidewalks, Mod Roadway 580 SF (0.01 AC) Modeled as Roads, Mod Lawn 18,346 SF (0.42 AC) Modeled as Lawn, C, Mod TOTAL LIMITS OF DISTURBANCE 23,642 SF (0.54 AC) See Above Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 22 ROW Dedication Roadway 1,959 SF (0.05 AC) Modeled as Roads, Mod ROW Dedication Lawn 777 SF (0.02 AC) Modeled as Pasture, C, Mod Lot 1 Rooftop 4,927 SF (0.11 AC) Modeled as Rooftops, Flat Lot 1 Driveway 375 SF (0.01 AC) Modeled as Driveways, Flat Lot 1 Lawn 4,975 SF (0.11 AC) Modeled as Pasture, C, Mod Lot 2 Rooftop 4,520 SF (0.10 AC) Modeled as Rooftops, Flat Lot 2 Driveway 375 SF (0.01 AC) Modeled as Driveways, Flat Lot 2 Lawn 4,641 SF (0.11 AC) Modeled as Pasture, C, Mod TOTAL LIMITS OF DISTURBANCE 23,642 SF (0.54 AC) See Above Part C: Performance Standards Based on the City of Renton’s flow control map, the project site is located within the Peak Rate Flow Control Standard (Existing Site Conditions). Flow control facilities are required to match the developed peak discharge rates to existing site conditions peak discharge rates for 2-, 10- and 100-year return periods. However, the site meets flow control exemption 2 per Section 1.2.3.1.A of the RSWDM, and flow control facilities are not required. In addition, the site is smaller than 22,000 SF. Therefore, the site is subject to Small Lot BMP Requirements detailed in Section 1.2.9.2.2 of the RSWDM. The site falls within a Basic Water Quality treatment area in accordance with Section 1.2.8.1.A of the RSWDM, however new plus replaced impervious pollution generating areas within the project site is under 5,000 SF and therefore water quality treatment is not required. Part D: Flow Control System As shown in the table on the following page, the proposed stormwater BMPs result in a 0.0073 CFS decrease in the 100-year flow using 15-minutes time steps. This is below the allowable threshold of a 0.15 CFS maximum increase per Section 1.2.3.1.B of the RSWDM; therefore, the project meets flow control exemption 2. No formal flow control facilities are proposed at this time; however, flow control BMPs will be implemented as described in Core Requirement #9 in Section II of this TIR. Please refer to Appendix B for a copy of the full WWHM data output. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 23 Part E: Water Quality System In accordance with Section 1.2.8.1.A of the RSWDM, Basic Water Quality Treatment is not required for this project as new plus replaced pollution generating impervious surfaces (PGIS) do not exceed 5,000 SF, meeting exemption 1. 1,949 SF of asphalt road repair and widening is proposed on N 24th St, 494 SF of concrete driveway is proposed within the ROW dedication area, and 750 SF of asphalt driveway is estimated within Lots 1 & 2 (at a 15-foot width). These quantities total to 3,193 SF of PGIS that will be created or replaced as a result of this project. Mangat Short Plat Technical Information Report 9/13/2021 P a g e | 24 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN The pipe outletting to the existing system was analyzed for capacity as it will be handling all of the flows and has the shallowest slope. An 8” pipe at 4.93% can convey 3.45 CFS. This is more than enough to safely covey the 100-year flowrate of 0.2616 CFS. Please see Mannings Calculator below. VI. SPECIAL REPORTS AND STUDIES · Limited Geotechnical Evaluation by Cobalt Geosciences dated August 20, 2020 VII. OTHER PERMITS · Final Short Plat · Building Permits · Right-of-Way Use Permit VIII. CSWPP ANALYSIS AND DESIGN A CSWPPP will be provided if requested. IX. BOND QUANTITIES AND DECLARATION of COVENANT Bond Quantities are included in Appendix C. A Declaration of Covenant is included in Appendix D. X. OPERATION AND MAINTENANCE MANUAL An Operation and Maintenance Manual is included in Appendix E. Mangat Short Plat Technical Information Report Appendix A Limited Geotechnical Evaluation by Cobalt Geosciences dated August 20, 2020 Mangat Short Plat Technical Information Report Appendix B WWHM Output WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 20547 Mangat Conveyance Calcs Site Name: Site Address: City : Report Date: 7/22/2021 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2019/09/13 Version : 4.2.17 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS MOD 0.08 SIDEWALKS MOD 0.02 Impervious Total 0.1 Basin Total 0.1 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre ROADS MOD 0.08 SIDEWALKS MOD 0.02 Impervious Total 0.1 Basin Total 0.1 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:0.1 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:0.1 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.044399 5 year 0.056373 10 year 0.064541 25 year 0.07517 50 year 0.083327 100 year 0.091701 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.044399 5 year 0.056373 10 year 0.064541 25 year 0.07517 50 year 0.083327 100 year 0.091701 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.056 0.056 1950 0.059 0.059 1951 0.033 0.033 1952 0.029 0.029 1953 0.035 0.035 1954 0.036 0.036 1955 0.043 0.043 1956 0.040 0.040 1957 0.042 0.042 1958 0.036 0.036 1959 0.040 0.040 1960 0.038 0.038 1961 0.037 0.037 1962 0.032 0.032 1963 0.038 0.038 1964 0.038 0.038 1965 0.044 0.044 1966 0.032 0.032 1967 0.051 0.051 1968 0.068 0.068 1969 0.040 0.040 1970 0.040 0.040 1971 0.049 0.049 1972 0.049 0.049 1973 0.032 0.032 1974 0.046 0.046 1975 0.049 0.049 1976 0.037 0.037 1977 0.037 0.037 1978 0.054 0.054 1979 0.066 0.066 1980 0.068 0.068 1981 0.042 0.042 1982 0.061 0.061 1983 0.050 0.050 1984 0.033 0.033 1985 0.042 0.042 1986 0.037 0.037 1987 0.057 0.057 1988 0.038 0.038 1989 0.060 0.060 1990 0.070 0.070 1991 0.062 0.062 1992 0.033 0.033 1993 0.041 0.041 1994 0.036 0.036 1995 0.039 0.039 1996 0.050 0.050 1997 0.039 0.039 1998 0.041 0.041 1999 0.089 0.089 2000 0.041 0.041 2001 0.051 0.051 2002 0.052 0.052 2003 0.053 0.053 2004 0.086 0.086 2005 0.034 0.034 2006 0.031 0.031 2007 0.081 0.081 2008 0.057 0.057 2009 0.063 0.063 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0887 0.0887 2 0.0862 0.0862 3 0.0811 0.0811 4 0.0703 0.0703 5 0.0682 0.0682 6 0.0679 0.0679 7 0.0656 0.0656 8 0.0630 0.0630 9 0.0623 0.0623 10 0.0608 0.0608 11 0.0600 0.0600 12 0.0586 0.0586 13 0.0575 0.0575 14 0.0573 0.0573 15 0.0562 0.0562 16 0.0545 0.0545 17 0.0527 0.0527 18 0.0523 0.0523 19 0.0512 0.0512 20 0.0511 0.0511 21 0.0505 0.0505 22 0.0495 0.0495 23 0.0492 0.0492 24 0.0491 0.0491 25 0.0489 0.0489 26 0.0459 0.0459 27 0.0435 0.0435 28 0.0425 0.0425 29 0.0425 0.0425 30 0.0418 0.0418 31 0.0416 0.0416 32 0.0415 0.0415 33 0.0414 0.0414 34 0.0409 0.0409 35 0.0404 0.0404 36 0.0402 0.0402 37 0.0401 0.0401 38 0.0400 0.0400 39 0.0389 0.0389 40 0.0386 0.0386 41 0.0384 0.0384 42 0.0383 0.0383 43 0.0382 0.0382 44 0.0381 0.0381 45 0.0370 0.0370 46 0.0369 0.0369 47 0.0369 0.0369 48 0.0365 0.0365 49 0.0362 0.0362 50 0.0361 0.0361 51 0.0356 0.0356 52 0.0347 0.0347 53 0.0338 0.0338 54 0.0334 0.0334 55 0.0327 0.0327 56 0.0325 0.0325 57 0.0322 0.0322 58 0.0319 0.0319 59 0.0315 0.0315 60 0.0313 0.0313 61 0.0290 0.0290 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility PASSED The Facility PASSED. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0222 1401 1401 100 Pass 0.0228 1284 1284 100 Pass 0.0234 1167 1167 100 Pass 0.0241 1064 1064 100 Pass 0.0247 980 980 100 Pass 0.0253 902 902 100 Pass 0.0259 819 819 100 Pass 0.0265 739 739 100 Pass 0.0271 671 671 100 Pass 0.0278 610 610 100 Pass 0.0284 552 552 100 Pass 0.0290 509 509 100 Pass 0.0296 470 470 100 Pass 0.0302 435 435 100 Pass 0.0308 412 412 100 Pass 0.0315 373 373 100 Pass 0.0321 345 345 100 Pass 0.0327 326 326 100 Pass 0.0333 304 304 100 Pass 0.0339 279 279 100 Pass 0.0345 262 262 100 Pass 0.0352 246 246 100 Pass 0.0358 234 234 100 Pass 0.0364 221 221 100 Pass 0.0370 203 203 100 Pass 0.0376 191 191 100 Pass 0.0383 176 176 100 Pass 0.0389 168 168 100 Pass 0.0395 160 160 100 Pass 0.0401 151 151 100 Pass 0.0407 141 141 100 Pass 0.0413 131 131 100 Pass 0.0420 119 119 100 Pass 0.0426 113 113 100 Pass 0.0432 104 104 100 Pass 0.0438 98 98 100 Pass 0.0444 91 91 100 Pass 0.0450 84 84 100 Pass 0.0457 80 80 100 Pass 0.0463 76 76 100 Pass 0.0469 74 74 100 Pass 0.0475 70 70 100 Pass 0.0481 66 66 100 Pass 0.0487 63 63 100 Pass 0.0494 56 56 100 Pass 0.0500 54 54 100 Pass 0.0506 49 49 100 Pass 0.0512 46 46 100 Pass 0.0518 42 42 100 Pass 0.0525 41 41 100 Pass 0.0531 39 39 100 Pass 0.0537 36 36 100 Pass 0.0543 34 34 100 Pass 0.0549 33 33 100 Pass 0.0555 30 30 100 Pass 0.0562 30 30 100 Pass 0.0568 28 28 100 Pass 0.0574 26 26 100 Pass 0.0580 23 23 100 Pass 0.0586 20 20 100 Pass 0.0592 19 19 100 Pass 0.0599 19 19 100 Pass 0.0605 18 18 100 Pass 0.0611 17 17 100 Pass 0.0617 16 16 100 Pass 0.0623 15 15 100 Pass 0.0630 15 15 100 Pass 0.0636 13 13 100 Pass 0.0642 13 13 100 Pass 0.0648 13 13 100 Pass 0.0654 11 11 100 Pass 0.0660 10 10 100 Pass 0.0667 10 10 100 Pass 0.0673 9 9 100 Pass 0.0679 7 7 100 Pass 0.0685 6 6 100 Pass 0.0691 4 4 100 Pass 0.0697 4 4 100 Pass 0.0704 3 3 100 Pass 0.0710 3 3 100 Pass 0.0716 3 3 100 Pass 0.0722 3 3 100 Pass 0.0728 3 3 100 Pass 0.0734 3 3 100 Pass 0.0741 3 3 100 Pass 0.0747 3 3 100 Pass 0.0753 3 3 100 Pass 0.0759 3 3 100 Pass 0.0765 3 3 100 Pass 0.0772 3 3 100 Pass 0.0778 3 3 100 Pass 0.0784 3 3 100 Pass 0.0790 3 3 100 Pass 0.0796 3 3 100 Pass 0.0802 3 3 100 Pass 0.0809 3 3 100 Pass 0.0815 2 2 100 Pass 0.0821 2 2 100 Pass 0.0827 2 2 100 Pass 0.0833 2 2 100 Pass _____________________________________________________ ___________________________________________________________________ Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. ___________________________________________________________________ LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Total Volume Infiltrated 0.00 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Passed ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 20547 Mangat Site Name: Site Address: City : Report Date: 3/23/2021 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2019/09/13 Version : 4.2.17 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Mod .42 Pervious Total 0.42 Impervious Land Use acre ROADS MOD 0.01 ROOF TOPS FLAT 0.07 DRIVEWAYS FLAT 0.02 SIDEWALKS MOD 0.02 Impervious Total 0.12 Basin Total 0.54 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Pasture, Mod .24 Pervious Total 0.24 Impervious Land Use acre ROADS MOD 0.05 ROOF TOPS FLAT 0.21 DRIVEWAYS MOD 0.03 SIDEWALKS MOD 0.01 Impervious Total 0.3 Basin Total 0.54 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.42 Total Impervious Area:0.12 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.24 Total Impervious Area:0.3 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.083567 5 year 0.123869 10 year 0.154157 25 year 0.196622 50 year 0.231377 100 year 0.268872 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.124843 5 year 0.159267 10 year 0.182836 25 year 0.213592 50 year 0.237257 100 year 0.261597 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.139 0.169 1950 0.138 0.165 1951 0.081 0.106 1952 0.047 0.082 1953 0.043 0.093 1954 0.067 0.102 1955 0.070 0.114 1956 0.071 0.109 1957 0.096 0.129 1958 0.058 0.102 1959 0.048 0.104 1960 0.086 0.115 1961 0.073 0.107 1962 0.047 0.091 1963 0.077 0.109 1964 0.066 0.102 1965 0.102 0.130 1966 0.052 0.087 1967 0.135 0.147 1968 0.116 0.173 1969 0.092 0.117 1970 0.077 0.118 1971 0.094 0.139 1972 0.128 0.144 1973 0.043 0.085 1974 0.097 0.128 1975 0.101 0.138 1976 0.073 0.104 1977 0.066 0.101 1978 0.081 0.132 1979 0.079 0.173 1980 0.166 0.187 1981 0.078 0.127 1982 0.150 0.180 1983 0.085 0.142 1984 0.057 0.091 1985 0.078 0.121 1986 0.079 0.110 1987 0.081 0.163 1988 0.040 0.100 1989 0.054 0.139 1990 0.256 0.254 1991 0.181 0.190 1992 0.062 0.091 1993 0.041 0.087 1994 0.035 0.087 1995 0.067 0.112 1996 0.125 0.140 1997 0.093 0.123 1998 0.076 0.116 1999 0.202 0.240 2000 0.085 0.122 2001 0.063 0.133 2002 0.129 0.155 2003 0.113 0.143 2004 0.181 0.234 2005 0.077 0.107 2006 0.076 0.097 2007 0.236 0.225 2008 0.174 0.183 2009 0.104 0.158 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.2562 0.2538 2 0.2362 0.2398 3 0.2022 0.2343 4 0.1810 0.2249 5 0.1810 0.1899 6 0.1736 0.1865 7 0.1656 0.1828 8 0.1500 0.1796 9 0.1390 0.1731 10 0.1379 0.1730 11 0.1345 0.1689 12 0.1286 0.1649 13 0.1276 0.1632 14 0.1255 0.1581 15 0.1165 0.1545 16 0.1131 0.1469 17 0.1035 0.1436 18 0.1017 0.1428 19 0.1009 0.1416 20 0.0974 0.1400 21 0.0963 0.1387 22 0.0940 0.1386 23 0.0932 0.1375 24 0.0915 0.1331 25 0.0861 0.1323 26 0.0852 0.1299 27 0.0849 0.1289 28 0.0813 0.1280 29 0.0812 0.1270 30 0.0806 0.1225 31 0.0791 0.1220 32 0.0787 0.1206 33 0.0784 0.1175 34 0.0782 0.1166 35 0.0773 0.1159 36 0.0769 0.1150 37 0.0767 0.1144 38 0.0761 0.1125 39 0.0755 0.1105 40 0.0729 0.1090 41 0.0726 0.1086 42 0.0714 0.1068 43 0.0700 0.1068 44 0.0673 0.1057 45 0.0667 0.1041 46 0.0662 0.1040 47 0.0661 0.1024 48 0.0633 0.1023 49 0.0624 0.1016 50 0.0580 0.1013 51 0.0573 0.0995 52 0.0544 0.0973 53 0.0525 0.0935 54 0.0485 0.0913 55 0.0470 0.0911 56 0.0466 0.0906 57 0.0432 0.0875 58 0.0429 0.0872 59 0.0411 0.0869 60 0.0397 0.0846 61 0.0346 0.0824 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility FAILED Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0418 1096 6171 563 Fail 0.0437 951 5467 574 Fail 0.0456 826 4817 583 Fail 0.0475 706 4265 604 Fail 0.0494 627 3797 605 Fail 0.0514 561 3369 600 Fail 0.0533 504 2971 589 Fail 0.0552 457 2652 580 Fail 0.0571 412 2372 575 Fail 0.0590 371 2130 574 Fail 0.0609 333 1900 570 Fail 0.0628 304 1710 562 Fail 0.0648 283 1547 546 Fail 0.0667 263 1390 528 Fail 0.0686 242 1260 520 Fail 0.0705 223 1140 511 Fail 0.0724 204 1029 504 Fail 0.0743 191 921 482 Fail 0.0763 175 838 478 Fail 0.0782 160 763 476 Fail 0.0801 144 694 481 Fail 0.0820 132 625 473 Fail 0.0839 120 563 469 Fail 0.0858 113 515 455 Fail 0.0877 107 467 436 Fail 0.0897 102 439 430 Fail 0.0916 96 405 421 Fail 0.0935 92 380 413 Fail 0.0954 87 356 409 Fail 0.0973 84 330 392 Fail 0.0992 80 306 382 Fail 0.1012 76 279 367 Fail 0.1031 72 260 361 Fail 0.1050 67 236 352 Fail 0.1069 63 220 349 Fail 0.1088 62 201 324 Fail 0.1107 55 186 338 Fail 0.1126 52 175 336 Fail 0.1146 49 159 324 Fail 0.1165 47 150 319 Fail 0.1184 45 136 302 Fail 0.1203 43 129 300 Fail 0.1222 42 121 288 Fail 0.1241 41 118 287 Fail 0.1260 38 113 297 Fail 0.1280 36 107 297 Fail 0.1299 34 100 294 Fail 0.1318 34 93 273 Fail 0.1337 29 85 293 Fail 0.1356 28 81 289 Fail 0.1375 27 74 274 Fail 0.1395 24 68 283 Fail 0.1414 24 64 266 Fail 0.1433 22 62 281 Fail 0.1452 21 59 280 Fail 0.1471 21 55 261 Fail 0.1490 20 49 245 Fail 0.1509 18 47 261 Fail 0.1529 17 45 264 Fail 0.1548 17 39 229 Fail 0.1567 17 38 223 Fail 0.1586 16 35 218 Fail 0.1605 15 33 220 Fail 0.1624 15 32 213 Fail 0.1643 15 28 186 Fail 0.1663 13 26 200 Fail 0.1682 11 24 218 Fail 0.1701 11 21 190 Fail 0.1720 11 21 190 Fail 0.1739 10 19 190 Fail 0.1758 10 19 190 Fail 0.1778 9 18 200 Fail 0.1797 8 18 225 Fail 0.1816 6 16 266 Fail 0.1835 6 14 233 Fail 0.1854 5 14 280 Fail 0.1873 5 13 260 Fail 0.1892 5 12 240 Fail 0.1912 5 11 220 Fail 0.1931 5 10 200 Fail 0.1950 4 10 250 Fail 0.1969 4 10 250 Fail 0.1988 4 9 225 Fail 0.2007 3 9 300 Fail 0.2027 2 8 400 Fail 0.2046 2 7 350 Fail 0.2065 2 5 250 Fail 0.2084 2 5 250 Fail 0.2103 2 5 250 Fail 0.2122 2 5 250 Fail 0.2141 2 5 250 Fail 0.2161 2 5 250 Fail 0.2180 2 5 250 Fail 0.2199 2 5 250 Fail 0.2218 2 4 200 Fail 0.2237 2 4 200 Fail 0.2256 2 3 150 Fail 0.2275 2 3 150 Fail 0.2295 2 3 150 Fail 0.2314 2 3 150 Fail _____________________________________________________ The development has an increase in flow durations from 1/2 Predeveloped 2 year flow to the 2 year flow or more than a 10% increase from the 2 year to the 50 year flow. The development has an increase in flow durations for more than 50% of the flows for the range of the duration analysis. ___________________________________________________________________ Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0 acre-feet On-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. Off-line facility target flow: 0 cfs. Adjusted for 15 min: 0 cfs. ___________________________________________________________________ LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Total Volume Infiltrated 0.00 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2021; All Rights Reserved. Mangat Short Plat Technical Information Report Appendix C Bond Quantity Worksheet Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200••Section I: Project Information•••Section II: Bond Quantities Worksheets••Section II.a EROSION CONTROL (Stabilization/Erosion Sediment Control (ESC))•Section II.b TRANSPORTATION (Street and Site Improvements)•Section II.c DRAINAGE (Drainage and Stormwater Facilities): •Section II.d WATER - ONLY APPLICABLE IF WATER SERVICE IS PROVIDED BY CITY OF RENTON•Section II.e SANITARY SEWER - ONLY APPLICABLE IF SEWER SERVICE IS PROVIDED BY CITY OF RENTON••••••Section III. Bond Worksheet•BOND QUANTITY WORKSHEET INSTRUCTIONSThis worksheet is intended to be a "working" copy of the bond quantity worksheet, which will be used throughout all phases of the project, from initial submittal to project close-out approval. Submit this workbook, in its entirety, as follows:The following forms are to be completed by the engineer/developer/applicant as applicable to the project: The Bond Worksheet form will auto-calculate and auto-populate from the information provided in Section I and Section II.This section includes all pertinent information for the projectSection II contains a separate spreadsheet TAB for each of the following specialties: (1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for civil construction permit submittal. Hard copies are to be included as part of the Technical Information Report (TIR).(1) electronic copy (.xlsx format) and (1) hard copy of the entire workbook for final close-out submittal.This section must be completed in its entiretyInformation from this section auto-populates to all other relevant areas of the workbookThis section calculates the required Permit Bond for construction permit issuance as well as the required Maintenance Bond for project close-out submittals to release the permit bond on a project. All unit prices include labor, equipment, materials, overhead and profit. Complete the 'Quantity' columns for each of the appropriate section(s). Include existing Right-of-Way (ROW), Future Public Improvements and Private Improvements.The 'Quantity Remaining' column is only to be used when a project is under construction. The City allows one (1) bond reduction during the life of the project with the exception of the maintenance period reduction.Excel will auto-calculate and auto-populate the relevant fields and subtotals throughout the document. Only the 'Quantity' columns should need completing.Additional items not included in the lists can be added under the "write-in" sections. Provide a complete description, cost estimate and unit of measure for each write-in item. Note: Private improvements, with the exception of stormwater facilities, are not included in the bond amount calculation, but must be entered on the form. Stormwater facilities (public and private) are required to be included in the bond amount.Page 1 of 14Ref 8-H Bond Quantity WorksheetINSTRUCTIONSUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date Prepared: Name:PE Registration No:Firm Name:Firm Address:Phone No.Email Address:Project Name: Project Owner:CED Plan # (LUA):Phone:CED Permit # (U):Address: Site Address:Street Intersection:Addt'l Project Owner:Parcel #(s):Phone:Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NOWater Service Provided by:If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: AddressAbbreviated Legal Description:HILLMANS LK WN GARDEN OF EDEN # 5 W 139 FT OF E 493 FTCity, State, Zip1415 N 24th Street10623 SE 279TH STREETAdditional Project OwnerN 24th Street and Meadow Ave NLUA20-000133(917)225-97203/10/2021Prepared by:FOR APPROVALProject Phase 1callen@encompasses.netChad Allen38285Encompass Engineering and Surveying165 NE Juniper St, Issaquah, WA 98055(425)392-0250SITE IMPROVEMENT BOND QUANTITY WORKSHEETPROJECT INFORMATIONCITY OF RENTONCITY OF RENTON1 Select the current project status/phase from the following options: For Approval - Preliminary Data Enclosed, pending approval from the City; For Construction - Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout - Final Costs and Quantities Enclosed for Project Close-out SubmittalPhoneEngineer Stamp Required (all cost estimates must have original wet stamp and signature)Clearing and GradingUtility ProvidersN/AProject Location and DescriptionProject Owner InformationMangat Short PlatRenton, WA 98030334450-0234Sukhjinder MangatLUA20-000265Page 2 of 14Ref 8-H Bond Quantity WorksheetSECTION I PROJECT INFORMATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133UnitReference #PriceUnitQuantity CostBackfill & compaction-embankmentESC-16.50$ CY Check dams, 4" minus rockESC-2SWDM 5.4.6.380.00$ Each Catch Basin ProtectionESC-335.50$ Each135.50Crushed surfacing 1 1/4" minusESC-4WSDOT 9-03.9(3)95.00$ CY DitchingESC-59.00$ CY Excavation-bulkESC-62.00$ CY Fence, siltESC-7SWDM 5.4.3.11.50$ LF280420.00Fence, Temporary (NGPE)ESC-81.50$ LF Geotextile FabricESC-92.50$ SY Hay Bale Silt TrapESC-100.50$ Each HydroseedingESC-11SWDM 5.4.2.40.80$ SY25002,000.00Interceptor Swale / DikeESC-121.00$ LF Jute MeshESC-13SWDM 5.4.2.23.50$ SY Level SpreaderESC-141.75$ LF Mulch, by hand, straw, 3" deepESC-15SWDM 5.4.2.12.50$ SY Mulch, by machine, straw, 2" deepESC-16SWDM 5.4.2.12.00$ SY Piping, temporary, CPP, 6"ESC-1712.00$ LF Piping, temporary, CPP, 8"ESC-1814.00$ LF Piping, temporary, CPP, 12"ESC-1918.00$ LF Plastic covering, 6mm thick, sandbaggedESC-20SWDM 5.4.2.34.00$ SY Rip Rap, machine placed; slopesESC-21WSDOT 9-13.1(2)45.00$ CY Rock Construction Entrance, 50'x15'x1'ESC-22SWDM 5.4.4.11,800.00$ Each11,800.00Rock Construction Entrance, 100'x15'x1'ESC-23SWDM 5.4.4.13,200.00$ Each Sediment pond riser assemblyESC-24SWDM 5.4.5.22,200.00$ Each Sediment trap, 5' high berm ESC-25SWDM 5.4.5.119.00$ LF Sed. trap, 5' high, riprapped spillway berm section ESC-26SWDM 5.4.5.170.00$ LF Seeding, by handESC-27SWDM 5.4.2.41.00$ SY Sodding, 1" deep, level groundESC-28SWDM 5.4.2.58.00$ SY Sodding, 1" deep, sloped groundESC-29SWDM 5.4.2.510.00$ SY TESC SupervisorESC-30110.00$ HR161,760.00Water truck, dust controlESC-31SWDM 5.4.7140.00$ HR UnitReference #PriceUnitQuantity Cost EROSION/SEDIMENT SUBTOTAL:6,015.50SALES TAX @ 10%601.55EROSION/SEDIMENT TOTAL:6,617.05(A)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR EROSION & SEDIMENT CONTROLDescription No.(A)WRITE-IN-ITEMS Page 3 of 14Ref 8-H Bond Quantity WorksheetSECTION II.a EROSION_CONTROLUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostGENERAL ITEMS Backfill & Compaction- embankmentGI-16.00$ CYBackfill & Compaction- trenchGI-29.00$ CYClear/Remove Brush, by hand (SY)GI-31.00$ SYBollards - fixedGI-4240.74$ EachBollards - removableGI-5452.34$ EachClearing/Grubbing/Tree RemovalGI-610,000.00$ Acre0.55,000.00Excavation - bulkGI-72.00$ CYExcavation - TrenchGI-85.00$ CY20100.0020100.00Fencing, cedar, 6' highGI-920.00$ LFFencing, chain link, 4'GI-1038.31$ LFFencing, chain link, vinyl coated, 6' highGI-1120.00$ LFFencing, chain link, gate, vinyl coated, 20' GI-121,400.00$ EachFill & compact - common barrowGI-1325.00$ CY20500.0020500.00Fill & compact - gravel baseGI-1427.00$ CYFill & compact - screened topsoilGI-1539.00$ CYGabion, 12" deep, stone filled mesh GI-1665.00$ SYGabion, 18" deep, stone filled mesh GI-1790.00$ SYGabion, 36" deep, stone filled meshGI-18150.00$ SYGrading, fine, by handGI-192.50$ SYGrading, fine, with graderGI-202.00$ SYMonuments, 3' LongGI-21250.00$ EachSensitive Areas SignGI-227.00$ EachSodding, 1" deep, sloped groundGI-238.00$ SYSurveying, line & gradeGI-24850.00$ DaySurveying, lot location/linesGI-251,800.00$ AcreTopsoil Type A (imported)GI-2628.50$ CYTraffic control crew ( 2 flaggers )GI-27120.00$ HRTrail, 4" chipped woodGI-288.00$ SYTrail, 4" crushed cinderGI-299.00$ SYTrail, 4" top courseGI-3012.00$ SYConduit, 2"GI-315.00$ LFWall, retaining, concreteGI-3255.00$ SFWall, rockeryGI-3315.00$ SFSUBTOTAL THIS PAGE:600.005,600.00(B)(C)(D)(E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)Page 4 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)ROAD IMPROVEMENT/PAVEMENT/SURFACINGAC Grinding, 4' wide machine < 1000syRI-130.00$ SY3309,900.00AC Grinding, 4' wide machine 1000-2000syRI-216.00$ SYAC Grinding, 4' wide machine > 2000syRI-310.00$ SYAC Removal/DisposalRI-435.00$ SY33011,550.00Barricade, Type III ( Permanent )RI-556.00$ LFGuard RailRI-630.00$ LFCurb & Gutter, rolledRI-717.00$ LFCurb & Gutter, verticalRI-812.50$ LF1401,750.00Curb and Gutter, demolition and disposalRI-918.00$ LF1402,520.00Curb, extruded asphaltRI-105.50$ LFCurb, extruded concreteRI-117.00$ LFSawcut, asphalt, 3" depthRI-121.85$ LF350647.50Sawcut, concrete, per 1" depthRI-133.00$ LFSealant, asphaltRI-142.00$ LF350700.00Shoulder, gravel, 4" thickRI-1515.00$ SYSidewalk, 4" thickRI-1638.00$ SY1254,750.00Sidewalk, 4" thick, demolition and disposalRI-1732.00$ SYSidewalk, 5" thickRI-1841.00$ SYSidewalk, 5" thick, demolition and disposalRI-1940.00$ SYSign, Handicap RI-2085.00$ EachStriping, per stallRI-217.00$ EachStriping, thermoplastic, ( for crosswalk )RI-223.00$ SFStriping, 4" reflectorized lineRI-230.50$ LFAdditional 2.5" Crushed SurfacingRI-243.60$ SYHMA 1/2" Overlay 1.5" RI-2514.00$ SYHMA 1/2" Overlay 2"RI-2618.00$ SYHMA Road, 2", 4" rock, First 2500 SYRI-2728.00$ SY3309,240.00HMA Road, 2", 4" rock, Qty. over 2500SYRI-2821.00$ SYHMA Road, 4", 6" rock, First 2500 SYRI-2945.00$ SYHMA Road, 4", 6" rock, Qty. over 2500 SYRI-3037.00$ SYHMA Road, 4", 4.5" ATBRI-3138.00$ SYGravel Road, 4" rock, First 2500 SYRI-3215.00$ SYGravel Road, 4" rock, Qty. over 2500 SYRI-3310.00$ SYThickened EdgeRI-348.60$ LFSUBTOTAL THIS PAGE:36,307.504,750.00(B)(C)(D)(E)Page 5 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostSITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR STREET AND SITE IMPROVEMENTSQuantity Remaining (Bond Reduction) (B)(C)PARKING LOT SURFACINGNo.2" AC, 2" top course rock & 4" borrowPL-121.00$ SY2" AC, 1.5" top course & 2.5" base coursePL-228.00$ SY4" select borrowPL-35.00$ SY1.5" top course rock & 2.5" base coursePL-414.00$ SYSUBTOTAL PARKING LOT SURFACING:(B)(C)(D)(E)LANDSCAPING & VEGETATIONNo.Street TreesLA-1Median LandscapingLA-2Right-of-Way LandscapingLA-3Wetland LandscapingLA-4SUBTOTAL LANDSCAPING & VEGETATION:(B)(C)(D)(E)TRAFFIC & LIGHTINGNo.SignsTR-1Street Light System ( # of Poles)TR-2Traffic SignalTR-3Traffic Signal ModificationTR-4SUBTOTAL TRAFFIC & LIGHTING:(B)(C)(D)(E)WRITE-IN-ITEMSSUBTOTAL WRITE-IN ITEMS:STREET AND SITE IMPROVEMENTS SUBTOTAL:36,907.504,750.005,600.00SALES TAX @ 10%3,690.75475.00560.00STREET AND SITE IMPROVEMENTS TOTAL:40,598.255,225.006,160.00(B)(C)(D)(E)Page 6 of 14Ref 8-H Bond Quantity WorksheetSECTION II.b TRANSPORTATIONUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostDRAINAGE (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/DD-126.00$ SY* (CBs include frame and lid)BeehiveD-290.00$ EachThrough-curb Inlet FrameworkD-3400.00$ EachCB Type ID-41,500.00$ Each11,500.00CB Type ILD-51,750.00$ EachCB Type II, 48" diameterD-62,300.00$ Each for additional depth over 4' D-7480.00$ FTCB Type II, 54" diameterD-82,500.00$ Each for additional depth over 4'D-9495.00$ FTCB Type II, 60" diameterD-102,800.00$ Each for additional depth over 4'D-11600.00$ FTCB Type II, 72" diameterD-126,000.00$ Each for additional depth over 4'D-13850.00$ FTCB Type II, 96" diameterD-1414,000.00$ Each for additional depth over 4'D-15925.00$ FTTrash Rack, 12"D-16350.00$ EachTrash Rack, 15"D-17410.00$ EachTrash Rack, 18"D-18480.00$ EachTrash Rack, 21"D-19550.00$ EachCleanout, PVC, 4"D-20150.00$ EachCleanout, PVC, 6"D-21170.00$ EachCleanout, PVC, 8"D-22200.00$ EachCulvert, PVC, 4" D-2310.00$ LFCulvert, PVC, 6" D-2413.00$ LFCulvert, PVC, 8" D-2515.00$ LF25375.00Culvert, PVC, 12" D-2623.00$ LFCulvert, PVC, 15" D-2735.00$ LFCulvert, PVC, 18" D-2841.00$ LFCulvert, PVC, 24"D-2956.00$ LFCulvert, PVC, 30" D-3078.00$ LFCulvert, PVC, 36" D-31130.00$ LFCulvert, CMP, 8"D-3219.00$ LFCulvert, CMP, 12"D-3329.00$ LFSUBTOTAL THIS PAGE:1,875.00(B)(C)(D)(E)Quantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESPage 7 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, CMP, 15"D-3435.00$ LFCulvert, CMP, 18"D-3541.00$ LFCulvert, CMP, 24"D-3656.00$ LFCulvert, CMP, 30"D-3778.00$ LFCulvert, CMP, 36"D-38130.00$ LFCulvert, CMP, 48"D-39190.00$ LFCulvert, CMP, 60"D-40270.00$ LFCulvert, CMP, 72"D-41350.00$ LFCulvert, Concrete, 8"D-4242.00$ LFCulvert, Concrete, 12"D-4348.00$ LFCulvert, Concrete, 15"D-4478.00$ LFCulvert, Concrete, 18"D-4548.00$ LFCulvert, Concrete, 24"D-4678.00$ LFCulvert, Concrete, 30"D-47125.00$ LFCulvert, Concrete, 36"D-48150.00$ LFCulvert, Concrete, 42"D-49175.00$ LFCulvert, Concrete, 48"D-50205.00$ LFCulvert, CPE Triple Wall, 6" D-5114.00$ LFCulvert, CPE Triple Wall, 8" D-5216.00$ LFCulvert, CPE Triple Wall, 12" D-5324.00$ LFCulvert, CPE Triple Wall, 15" D-5435.00$ LFCulvert, CPE Triple Wall, 18" D-5541.00$ LFCulvert, CPE Triple Wall, 24" D-5656.00$ LFCulvert, CPE Triple Wall, 30" D-5778.00$ LFCulvert, CPE Triple Wall, 36" D-58130.00$ LFCulvert, LCPE, 6"D-5960.00$ LFCulvert, LCPE, 8"D-6072.00$ LFCulvert, LCPE, 12"D-6184.00$ LFCulvert, LCPE, 15"D-6296.00$ LFCulvert, LCPE, 18"D-63108.00$ LFCulvert, LCPE, 24"D-64120.00$ LFCulvert, LCPE, 30"D-65132.00$ LFCulvert, LCPE, 36"D-66144.00$ LFCulvert, LCPE, 48"D-67156.00$ LFCulvert, LCPE, 54"D-68168.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 8 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESDRAINAGE (Continued)Culvert, LCPE, 60"D-69180.00$ LFCulvert, LCPE, 72"D-70192.00$ LFCulvert, HDPE, 6"D-7142.00$ LFCulvert, HDPE, 8"D-7242.00$ LFCulvert, HDPE, 12"D-7374.00$ LFCulvert, HDPE, 15"D-74106.00$ LFCulvert, HDPE, 18"D-75138.00$ LFCulvert, HDPE, 24"D-76221.00$ LFCulvert, HDPE, 30"D-77276.00$ LFCulvert, HDPE, 36"D-78331.00$ LFCulvert, HDPE, 48"D-79386.00$ LFCulvert, HDPE, 54"D-80441.00$ LFCulvert, HDPE, 60"D-81496.00$ LFCulvert, HDPE, 72"D-82551.00$ LFPipe, Polypropylene, 6"D-8384.00$ LFPipe, Polypropylene, 8"D-8489.00$ LFPipe, Polypropylene, 12"D-8595.00$ LFPipe, Polypropylene, 15"D-86100.00$ LFPipe, Polypropylene, 18"D-87106.00$ LFPipe, Polypropylene, 24"D-88111.00$ LFPipe, Polypropylene, 30"D-89119.00$ LFPipe, Polypropylene, 36"D-90154.00$ LFPipe, Polypropylene, 48"D-91226.00$ LFPipe, Polypropylene, 54"D-92332.00$ LFPipe, Polypropylene, 60"D-93439.00$ LFPipe, Polypropylene, 72"D-94545.00$ LFCulvert, DI, 6"D-9561.00$ LFCulvert, DI, 8"D-9684.00$ LFCulvert, DI, 12"D-97106.00$ LFCulvert, DI, 15"D-98129.00$ LFCulvert, DI, 18"D-99152.00$ LFCulvert, DI, 24"D-100175.00$ LFCulvert, DI, 30"D-101198.00$ LFCulvert, DI, 36"D-102220.00$ LFCulvert, DI, 48"D-103243.00$ LFCulvert, DI, 54"D-104266.00$ LFCulvert, DI, 60"D-105289.00$ LFCulvert, DI, 72"D-106311.00$ LFSUBTOTAL THIS PAGE:(B)(C)(D)(E)Page 9 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESSpecialty Drainage ItemsDitching SD-19.50$ CYFlow Dispersal Trench (1,436 base+)SD-328.00$ LF 1004,236.00 French Drain (3' depth)SD-426.00$ LFGeotextile, laid in trench, polypropyleneSD-53.00$ SYMid-tank Access Riser, 48" dia, 6' deepSD-62,000.00$ EachPond Overflow SpillwaySD-716.00$ SYRestrictor/Oil Separator, 12"SD-81,150.00$ EachRestrictor/Oil Separator, 15"SD-91,350.00$ EachRestrictor/Oil Separator, 18"SD-101,700.00$ EachRiprap, placedSD-1142.00$ CYTank End Reducer (36" diameter)SD-121,200.00$ EachInfiltration pond testingSD-13125.00$ HRPermeable PavementSD-14Permeable Concrete SidewalkSD-15Culvert, Box __ ft x __ ftSD-16SUBTOTAL SPECIALTY DRAINAGE ITEMS:4,236.00(B)(C)(D)(E)STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch)Detention PondSF-1Each Detention TankSF-2Each Detention VaultSF-3Each Infiltration PondSF-4Each Infiltration TankSF-5Each Infiltration VaultSF-6Each Infiltration TrenchesSF-7Each Basic Biofiltration SwaleSF-8Each Wet Biofiltration SwaleSF-9Each WetpondSF-10Each WetvaultSF-11Each Sand FilterSF-12Each Sand Filter VaultSF-13Each Linear Sand FilterSF-14Each Proprietary FacilitySF-15Each Bioretention FacilitySF-16Each SUBTOTAL STORMWATER FACILITIES:(B)(C)(D)(E)Page 10 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostQuantity Remaining (Bond Reduction) (B)(C)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR DRAINAGE AND STORMWATER FACILITIESWRITE-IN-ITEMS (INCLUDE ON-SITE BMPs)WI-1WI-2WI-3WI-4WI-5WI-6WI-7WI-8WI-9WI-10WI-11WI-12WI-13WI-14WI-15SUBTOTAL WRITE-IN ITEMS:DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:1,875.004,236.00SALES TAX @ 10%187.50423.60DRAINAGE AND STORMWATER FACILITIES TOTAL:2,062.504,659.60(B) (C) (D) (E)Page 11 of 14Ref 8-H Bond Quantity WorksheetSECTION II.c DRAINAGEUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostConnection to Existing WatermainW-12,000.00$ Each24,000.00Ductile Iron Watermain, CL 52, 4 Inch DiameterW-250.00$ LFDuctile Iron Watermain, CL 52, 6 Inch DiameterW-356.00$ LFDuctile Iron Watermain, CL 52, 8 Inch DiameterW-460.00$ LFDuctile Iron Watermain, CL 52, 10 Inch DiameterW-570.00$ LFDuctile Iron Watermain, CL 52, 12 Inch DiameterW-680.00$ LFGate Valve, 4 inch DiameterW-7500.00$ EachGate Valve, 6 inch DiameterW-8700.00$ EachGate Valve, 8 Inch DiameterW-9800.00$ EachGate Valve, 10 Inch DiameterW-101,000.00$ EachGate Valve, 12 Inch DiameterW-111,200.00$ EachFire Hydrant AssemblyW-124,000.00$ EachPermanent Blow-Off AssemblyW-131,800.00$ EachAir-Vac Assembly, 2-Inch DiameterW-142,000.00$ EachAir-Vac Assembly, 1-Inch DiameterW-151,500.00$ EachCompound Meter Assembly 3-inch DiameterW-168,000.00$ EachCompound Meter Assembly 4-inch DiameterW-179,000.00$ EachCompound Meter Assembly 6-inch DiameterW-1810,000.00$ EachPressure Reducing Valve Station 8-inch to 10-inchW-1920,000.00$ EachWATER SUBTOTAL:4,000.00SALES TAX @ 10%400.00WATER TOTAL:4,400.00(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR WATERQuantity Remaining (Bond Reduction) (B)(C)Page 12 of 14Ref 8-H Bond Quantity WorksheetSECTION II.d WATERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 CED Permit #:LUA20-000133ExistingFuture PublicPrivateRight-of-WayImprovementsImprovements(D) (E)DescriptionNo. Unit PriceUnitQuant.CostQuant.CostQuant.CostQuant.CostClean OutsSS-11,000.00$ Each22,000.00Grease Interceptor, 500 gallonSS-28,000.00$ EachGrease Interceptor, 1000 gallonSS-310,000.00$ EachGrease Interceptor, 1500 gallonSS-415,000.00$ EachSide Sewer Pipe, PVC. 4 Inch DiameterSS-580.00$ LFSide Sewer Pipe, PVC. 6 Inch DiameterSS-695.00$ LF605,700.00Sewer Pipe, PVC, 8 inch DiameterSS-7105.00$ LFSewer Pipe, PVC, 12 Inch DiameterSS-8120.00$ LFSewer Pipe, DI, 8 inch DiameterSS-9115.00$ LFSewer Pipe, DI, 12 Inch DiameterSS-10130.00$ LFManhole, 48 Inch DiameterSS-116,000.00$ EachManhole, 54 Inch DiameterSS-136,500.00$ EachManhole, 60 Inch DiameterSS-157,500.00$ EachManhole, 72 Inch DiameterSS-178,500.00$ EachManhole, 96 Inch DiameterSS-1914,000.00$ EachPipe, C-900, 12 Inch DiameterSS-21180.00$ LFOutside DropSS-241,500.00$ LSInside DropSS-251,000.00$ LSSewer Pipe, PVC, ____ Inch DiameterSS-26Lift Station (Entire System)SS-27LSSANITARY SEWER SUBTOTAL:5,700.002,000.00SALES TAX @ 10%570.00200.00SANITARY SEWER TOTAL:6,270.002,200.00(B) (C) (D) (E)SITE IMPROVEMENT BOND QUANTITY WORKSHEETFOR SANITARY SEWERQuantity Remaining (Bond Reduction) (B)(C)Page 13 of 14Ref 8-H Bond Quantity WorksheetSECTION II.e SANITARY SEWERUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 Planning Division |1055 South Grady Way – 6th Floor | Renton, WA 98057 (425) 430-7200Date: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)51,268.25$ Future Public Improvements Subtotal(c)5,225.00$ Stormwater & Drainage Facilities (Public & Private) Subtotal(d)(d)6,722.10$ (e)(f)Site RestorationCivil Construction PermitMaintenance Bond12,643.07$ Bond Reduction2Construction Permit Bond Amount 3Minimum Bond Amount is $10,000.001 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering.2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% willcover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering.* Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton.** Note: All prices include labor, equipment, materials, overhead and profit. EST1((b) + (c) + (d)) x 20%-$ MAINTENANCE BOND */**(after final acceptance of construction)6,617.05$ 51,268.25$ 83,624.48$ 6,617.05$ -$ 6,722.10$ -$ 90,241.53$ P (a) x 100%SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS3/10/2021Chad Allen38285Encompass Engineering and SurveyingR((b x 150%) + (d x 100%))S(e) x 150% + (f) x 100%Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2T(P +R - S)Prepared by:Project InformationCONSTRUCTION BOND AMOUNT */**(prior to permit issuance)(425)392-0250callen@encompasses.netMangat Short PlatLUA20-0002651415 N 24th Street334450-0234FOR APPROVALLUA20-000133165 NE Juniper St, Issaquah, WA 98055Page 14 of 14Ref 8-H Bond Quantity WorksheetSECTION III. BOND WORKSHEETUnit Prices Updated: 06/14/2016Version: 04/26/2017Printed 4/2/2021 Mangat Short Plat Technical Information Report Appendix D 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 Sukhjinder Mangat HILLMANS LK WN GARDEN OF EDEN # 5 W 139 FT OF E 493 FT 334450-0234 T.B.D. T.B.D. T.B.D. 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 MAINTENANCE INSTRUCTIONS FOR BASIC DISPERSION Your property contains a stormwater management flow control BMP (best management practice) called "basic dispersion," which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces or non-native pervious surfaces on your property. Basic dispersion is a strategy for utilizing any available capacity of onsite vegetated areas to retain, absorb, and filter the runoff from developed surfaces. This flow control BMP has two primary components that must be maintained: (1) the devices that disperse runoff from the developed surfaces and (2) the vegetated area over which runoff is dispersed. Dispersion Devices The dispersion devices used on your property include the following as indicated on the flow control BMP site plan (CHECK THE BOX(ES) THAT APPLY): splash blocks, rock pads, gravel filled trenches, sheet flow. MAINTENANCE RESTRICTIONS The size, placement, composition, and downstream flowpaths of these devices as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES This flow control BMP has two primary components that must be maintained: (1) the devices that disperse runoff from the developed surfaces and (2) the vegetated flowpath area over which runoff is dispersed. Maintenance of Dispersion Devices • Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. • When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. • Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. Maintenance of Vegetated Flowpaths • The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows. RECORDING REQUIREMENT These basic dispersion flow control 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 King County 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 King County Department of Permitting and Environmental Services (DPER) may require additional instructions based on site-specific conditions. See King County’s Surface Water Design Manual website for additional information and updates. 4 Mangat Short Plat Technical Information Report Appendix E Operations and Maintenance Manual MAINTENANCE INSTRUCTIONS FOR BASIC DISPERSION Your property contains a stormwater management flow control BMP (best management practice) called "basic dispersion," which was installed to mitigate the stormwater quantity and quality impacts of some or all of the impervious surfaces or non-native pervious surfaces on your property. Basic dispersion is a strategy for utilizing any available capacity of onsite vegetated areas to retain, absorb, and filter the runoff from developed surfaces. This flow control BMP has two primary components that must be maintained: (1) the devices that disperse runoff from the developed surfaces and (2) the vegetated area over which runoff is dispersed. Dispersion Devices The dispersion devices used on your property include the following as indicated on the flow control BMP site plan (CHECK THE BOX(ES) THAT APPLY): splash blocks, rock pads, gravel filled trenches, sheet flow. MAINTENANCE RESTRICTIONS The size, placement, composition, and downstream flowpaths of these devices as depicted by the flow control BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land Resources Division or through a future development permit from King County. INSPECTION FREQUENCY AND MAINTENANCE GUIDELINES This flow control BMP has two primary components that must be maintained: (1) the devices that disperse runoff from the developed surfaces and (2) the vegetated flowpath area over which runoff is dispersed. Maintenance of Dispersion Devices • Dispersion devices must be inspected annually and after major storm events to identify and repair any physical defects. • When native soil is exposed or erosion channels are present, the sources of the erosion or concentrated flow need to be identified and mitigated. • Concentrated flow can be mitigated by leveling the edge of the pervious area and/or realigning or replenishing the rocks in the dispersion device, such as in rock pads and gravel filled trenches. Maintenance of Vegetated Flowpaths • The vegetated area over which runoff is dispersed must be maintained in good condition free of bare spots and obstructions that would concentrate flows. RECORDING REQUIREMENT These basic dispersion flow control 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 King County 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 King County Department of Permitting and Environmental Services (DPER) may require additional instructions based on site-specific conditions. See King County’s Surface Water Design Manual website for additional information and updates. 4 TYPICAL SPLASH BLOCK TYPICAL 10-FOOT DISPERSION TRENCH CROSS-SECTION TYPICAL DRIVEWAY APPLICATION OF DISPERSION TRENCH AND ROCK PAD SIDE VIEW NTS HOUSE DOWNSPOUT EXTENSION SPLASH BLOCK ROOF DOWNSPOUT SPLASH BLOCK 100' MIN. VEGETATED FLOWPATH UNDER FULL DISPERSION, SEE SECTION C.2.1.3 10-foot long dispersion trench Vegetated Flowpath Segment (NVFS) Slot drain Diagonal asphalt berm – 2 to 4 inches high PLAN VIEW OF DRIVEWAY NTS 2-ft x 3-ft x 6-inch crushed rock pad 50-foot separation between flowpath segments Vegetated Flowpath Segment Edge of undisturbed native vegetation