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HomeMy WebLinkAboutRS_TIR_JDL_Properties_190410_v2.pdf Western Washington Division Eastern Washington Division 165 NE Juniper St., Ste 201, Issaquah, WA 98027 108 East 2nd Street, 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 JDL Duplex 10801 SE 170th Street Renton, WA 98055 Date: September 4, 2018 Revised On: December 28, 2018 Revised On: April 10, 2019 Prepared by: Daniel R. Davis Encompass Engineering Job No. 17707 Prepared For: JDL Properties LLC 705 214th Avenue SE Sammamish, WA 98074 JDL Duplex Technical Information Report March 19, 2018 Page i Table of Contents I. PROJECT OVERVIEW ................................................................................................................ 1 II. CONDITIONS AND REQUIREMENTS SUMMARY ...................................................................... 2 III. OFF-SITE ANALYSIS .................................................................................................................. 5 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ............................. 9 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN ..................................................................... 12 VI. SPECIAL REPORTS AND STUDIES ............................................................................................ 12 VII. OTHER PERMITS ..................................................................................................................... 13 VIII. CSWPPP ANALYSIS AND DESIGN............................................................................................ 13 IX. BOND QUANTITIES and DECLARATION of COVENANT .......................................................... 15 X. OPERATION AND MAINTENANCE MANUAL .......................................................................... 15 Appendix A Infiltration Evaluation (prepared by Earth Solutions NW LLC) Appendix B WWHM2012 Project Report Appendix C Conveyance Capacity Calculations. JDL Duplex Technical Information Report Page 1 I. PROJECT OVERVIEW Site Address: 10801 SE 170th Street Renton, Wa. 98055 King County Tax Parcel: 292305-9026 General. The subject property contains an area of 17,172 square feet (0.39-acre) and is zoned R-14. The land owner proposes to construct a duplex building with access driveway and frontage improvements. The property will be serviced by the Soos Creek Water and Sewer District. Project Location. The project parcel number is 292305-9026. The street address for the site is 10801 SE 170th Street Renton, Wa. 98055. See Figure 2 for more information. Existing and Proposed Project Site Characteristics. The parcel has previously been developed and contains an existing duplex building, paved driveway, and patios. The remainder of the site covered is mostly with grass and vegetation. Critical Areas. Based on the available information, there are no critical areas located on the project site. Soils. According to USDA soil maps, the onsite soils are classified as Alderwood Gravelly Sandy Loam (AgC) with 8 to 15 percent slopes. These soils are considered glacial till deposits. See figure 4 for NRCS soils map and Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW. Proposed Storm Water Controls. The proposed storm water control has been designed according to the standards set forth by the 2017 City of Renton Surface Water Design Manual (2017 COR SWDM). This project involves construction of a duplex with paved driveway and patio areas. This project creates a total of 7,125 sq-ft of new impervious surface area including 3,054 sq-ft of offsite impervious surface and 4,021 sq-ft of onsite impervious surface area. The project is subject to Full Drainage Review per the Pre-Application Meeting Notes. It is proposed that Flow Control BMPs for Basic Dispersion will be implemented per 2017 City of Renton Surface Water Design Manual requirements. Refer to Section 4 of this TIR for additional information regarding the Flow Control and Water Quality BMPs. 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 __________________ __________________ __________________ 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 ______________________  _____________________________________ 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: _________________________ 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: 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 _______________________________ King County Date: 3/19/2018 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject to change without notice. King County makes no representations or warranties, express or implied,as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. Site Location Map King County Date: 3/19/2018 Notes: ±The information included on this map has been compiled by King County staff from a variety of sources and issubject to change without notice. King County makes no representations or warranties, express or implied,as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intendedfor use as a survey product. King County shall not be liable for any general, special, indirect, incidental, orconsequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuseof the information contained on this map. Any sale of this map or information on this map is prohibited except bywritten permission of King County. Drainage Basin Map Figure 4 – Soils Map JDL Duplex Technical Information Report Page 2 II. CONDITIONS AND REQUIREMENTS SUMMARY Conditions and Requirements Provide Basic Dispersion per 2017 COR SWDM Section C.2.4: • Section C.2.4.1 - Minimum Design Requirements for Basic Dispersion • Section C.2.4.2 - Use of Splash Blocks for Basic Dispersion • Section C.2.4.4 - Use of Gravel Filled Trenches for Basic Dispersion • Section C.2.4.5 - Use of Sheet Flow for Basic Dispersion CORE REQUIREMENTS Core Requirement #1: Discharge at the natural Location Runoff from the site generally sheet flows across the site in a southerly direction, toward a ground depression. The ground depression is drained by an 18” culvert which spans the property from the south to the north and conveys site flows into the City of Renton’s storm sewer system located in SE 170th Street. The proposed project will continue to discharge site flows into the storm sewer system within SE 170th Street. Refer to the Level 1 Downstream Analysis in Section 3 for a complete description of the existing drainage path. Core Requirement #2: Offsite Analysis An offsite drainage analysis is provided in Section 3 of this TIR. Level 1 Drainage Analysis has been prepared and no problems were identified. Core Requirement #3: Flow Control This project is a multi-family dwelling and qualifies for Full Drainage Review. The project qualifies for an exception from the flow control facility requirement. Flow control BMPs for basic dispersion will provide the required flow control for proposed improvements. See Section IV of this TIR for more information on Flow Control. Core Requirement #4: Conveyance System Conveyance system analysis is not required for the project. See Section V of this TIR for more information. Core Requirement #5: Erosion and Sediment Control A temporary erosion and sediment control (TESC) plan provides BMPs to be implemented during construction. See Section VIII of this TIR for additional TESC measures to be implemented. Core Requirement #6: Maintenance and Operations See Section X – Operation and Maintenance Manual JDL Duplex Technical Information Report Page 3 Core Requirement #7: Financial Guarantees and Liability The owner will arrange for any financial guarantees and liabilities required by the permit. Core Requirement #8: Water Quality Water quality treatment is not required for the project since the project will result in less than 5,000 sq-ft of new/replaced pollution-generating impervious surface area. Core Requirement #9: The project parcel under proposed condition is 13,363 sq-ft in size, which is less than 22,000 sq-ft. Therefore, the minimum required mitigation is 20% of the lot size (13,363 sq-ft x 0.20 = 2,673 sq-ft to be mitigated) per 2017 COR SWDM Section 1.2.9.2.1 “Small Lot Bmp Requirements”. Mitigation is not proposed for the new driveway surface area or the proposed offsite impervious surface areas. Existing impervious surfaces on the property were constructed prior to January 8, 2001 and therefore are not required to be mitigated. The new impervious rooftop area will drain to 2 basic dispersion trenches and 1 splash blocks for basic dispersion to mitigate approximately 2,800 sq-ft of rooftop area, which is exceeds the minimum 2,673 sq-ft of impervious surface required to be mitigated. Roof drains pass through a perforated pipe connection prior to discharge to public storm system. See Section IV of this TIR for more information regarding Core Requirement #9 and Flow Control BMP design. SPECIAL REQUIREMENTS: Special Requirement #1: Other Adopted Area-Specific Requirements Critical Drainage Area – N/A Master Drainage Plan – N/A Basin Plan – This site is located within the Black River drainage basin Lake management Plan – N/A Shared Facility Drainage Plan – N/A Special Requirement #2: Floodplain/Floodway Delineation The limits of this project do not lie in a 100-year floodplain Special Requirement #3: Flood Protection Facilities This special requirement is required for projects with Class 1 or 2 streams with an existing flood protection facility. The site does not contain any streams and is therefore not applicable. Special Requirement #4: Source controls This project is a multi-family duplex project and this requirement is not applicable. Special Requirement #6: Aquifer Protection Area This project is not considered high-use in need of oil control. JDL Duplex Technical Information Report Page 4 Special Requirement #6: Aquifer Protection Area This project is not located within an aquifer protection area. JDL Duplex Technical Information Report Page 5 III. OFF-SITE ANALYSIS A downstream analysis was conducted on January 22, 2018. Weather conditions were partial clouds with temperatures around 45 degrees Fahrenheit. The downstream analysis extended a minimum of one-quarter mile from the site’s discharge location. The project site is generally flat and slopes toward the northern and southern limits of the property. All stormwater onsite is collected by either an open-ended 18” culvert at the southern property limit or to a drainage structure located near the northern property limit. The area of the lot where new construction will occur is covered with grass, with a few bushes. An existing duplex with driveway and patio areas are currently located on the western half of the lot. A Downstream Drainage Map is provided at the end of Section III which indicates the direction of site flows. As mentioned above, stormwater runoff from the area to be developed is collected by an onsite stormwater conveyance system in pre-developed condition. Stormwater runoff from the site either sheet flows toward an open-ended 18” CMP culvert at point A, located in the south-east portion of the lot, or sheet flows toward a catch basin at point B, which is located in the north-east portion of the lot. The onsite 18” CMP culvert connects to the onsite catch basin (at point B) and flows collected by the catch basin appear to drain toward the shallow depression at the downstream end of the 18” CMP culvert (at point A), based on surveyed invert elevations. However, it is believed that the flows from the site ultimately drain north toward SE 170th Street when the depression (at point A) fills up with enough water. The rim elevation for the onsite catch basin (at point B) is lower than the existing ground around the onsite ground depression. Therefore, the flows are presumed to be conveyed north by an 18” CMP pipe which extends north from the existing onsite catch basin (at point B), or the flows are presumed to discharge out of an 8” CMP pipe (at point C), which is connected to the existing onsite catch basin (at point B), presuming the north bound CMP pipe is stubbed. The flow would then enter a catch basin in front of the property (at point D), which is located on the south side of SE 170th Street. The roadside catch basin (at point D) is connected to a catch basin (Facility ID No. 111772) on the north side of the street (at point E) via a 34 foot long 12” polyethylene pipe, which connects to an existing storm sewer line beneath the north curb-line of SE 170th Street. If the north bound 18” CMP pipe is not a stub, it’s assumed that this pipe connects to the storm sewer line that runs along the north curb-line of SE 170th Street via a blind connection and pipe reducer (at point F). Regardless, the flows would travel west along the existing 12” polyethylene pipe beneath the north curb-line of SE 170th Street for a distance of approximately 150 feet until it reaches a Catch Basin (Facility ID No. 111772) at point G. From there, the site flows would travel southeast for a distance of approximately 78 feet through a 12 inch polyethylene pipe until it reaches a Catch Basin (Facility ID No. 112740) at point H. From there, the flows travel south along a 18” polyethylene pipe for a distance of approximately 93 feet until it enters a Catch Basin (Facility ID No. 112739) at point I. From there, the flows continue to travel south via an 18” polyethylene pipe for a distance of approximately 110 feet until it reaches a Catch Basin (Facility ID No. 112737) at point J. From there, the flows continue traveling south via an 18” polyethylene pipe for a distance of approximately 68 feet until it reaches a Catch Basin (Facility ID No. 112738) at point K. From there, the site flows continue traveling south via an 18” polyethylene pipe for a distance of approximately 107 feet until it reaches a Catch Basin (Facility ID No. 112736) at point L. From there, the site flows continue traveling south via an 12” corrugated metal pipe for a distance of approximately 107 feet until it reaches a Catch Basin (Facility ID No. 135645) at point M. From there, the site flows continue traveling south via an JDL Duplex Technical Information Report Page 6 18” corrugated metal pipe for a distance of approximately 18 feet until it reaches a Catch Basin (Facility ID No. 501909) at point N. From there, the site flows continue traveling south via an 18” corrugated metal pipe for a distance of approximately 80 feet until it reaches a Catch Basin (Facility ID No. 118949) at point O. From there, the site flows travel west via an 18” corrugated metal pipe for a distance of approximately 82 feet until it reaches a newly built Catch Basin at point P. From there, the site flows travel west via an 18” corrugated plastic pipe for a distance of approximately 285 feet until it discharges into an existing creek, at which point the downstream analysis was concluded. No significant erosion or drainage problems were identified during the downstream analysis. See photos below for site and downstream drainage flowpath areas. Photo 1 - Shows the existing duplex located on the subject property. JDL Duplex Technical Information Report Page 7 Photo 2 - Shows the subject property where the new duplex will be constructed. Photo 3 – Shows existing catch basins located on the property and within SE 170th Street. JDL Duplex Technical Information Report Page 8 Photo 4 – Shows an existing ground depression located at the south property limit on the eastern half of the parcel. Photo 5 – Shows the downstream outfall location where flows enter a creek. The outfall is located along SE 172nd Street, just south of the address at 10717 SE 172nd Street. Downstream Drainage Map JDL Duplex Technical Information Report Page 9 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN Proposed Drainage Overview The site storm drainage system has been designed according to the standards set forth by the 2017 City of Renton Surface Water Design Manual. The project results in more than 5,000 sq-ft of total impervious surface area with frontage improvements included. The project is located within the Flow Control Duration Standard (Forested Conditions) Zone and qualifies for a facility requirement exception since there is less than a 0.15 cfs difference (when modeled using 15 minute time steps) in the sum of developed 100-year flows for new target surfaces compared to forested site condition. Therefore, Flow Control BMPs will used for mitigation for surface water runoff from new target impervious areas located onsite. Drainage Design This project will involve adding approximately 7,125 sq-ft of total new impervious surface to the parcel and public R/W. Runoff from the new frontage improvements will drain to the existing CB/pipe storm system in SE 170th Street. Flow Control BMPs for Basic Dispersion will be provide the minimum required mitigation of new/replaced surface areas. Due to the limited onsite space for Flow Control BMPs and since the project site is less than 22,000 sq-ft, an impervious area equal to 20% of the resulting lot area (post-dedication) is required to be mitigated. New onsite driveway pavement will drain to the existing storm sewer system in SE 170th Street. Ex. Impervious Surface Coverage: Ex. impervious and existing pervious surface summary (under post-developed condition): Ex. building rooftop impervious area: → 2,260 sq-ft (0.052 acre) Uncovered ex. onsite driveway impervious area: → 1,661 sq-ft (0.038 acre) Uncovered ex. patio impervious area: → 201 sq-ft (0.005 acre) Total ex. onsite impervious area: → 4,122 sq-ft (0.095 acre) Ex. pervious area: New lot area – total ex. onsite imp. area = 13,072 sq-ft – 4,122sq-ft = 8,950 sq-ft (0.205 acre) JDL Duplex Technical Information Report Page 10 WWHM2012 Analysis: Pre-Development Condition: • Existing Imp. Area → Ex. Bldg. Imp. Area = 0.052 acre (Flat) Ex. Drwy. Imp. Area = 0.038 acre (Flat) Ex. Patio Imp. Area = 0.005 acre (Flat) • Soil → Alderwood Gravelly Sandy Loam (Glacial Till) • Reg. Scale Factor → 1.0 (Seatac) • Time Step → 15-minute • Area of Disturbance: → 13,106 sq-ft Area of Disturbance = 13,106 sq-ft (0.301 acre) • Existing Pervious = Area of Disturbance – Ex. Impervious Area = (0.301 – 0.052 – 0.038 – 0.005) acre = 0.206 acre (forest coverage) Pre-Developed Q100-yr = 0.023263 cfs Post-Development Condition: • Soil → Alderwood Gravelly Sandy Loam (Glacial Till) • Reg. Scale Factor → 1.0 (Seatac) • Time Step → 15-minute • All new/replaced pervious and impervious surfaces were modeled as flat. New/replaced/existing impervious surface summary: New building rooftop impervious area: → 3,450 sq-ft (0.079 acre) Uncovered new driveway impervious area: → 1,796 sq-ft (0.041 acre) New sidewalk impervious area: → 1,708 sq-ft (0.039 acre) Ex. building rooftop impervious area: → 2,260 sq-ft (0.052 acre) Uncovered ex. onsite driveway impervious area: → 1,661 sq-ft (0.038 acre) Uncovered ex. patio impervious area: → 201 sq-ft (0.005 acre) Total impervous surface area (post-developed): → 11,076 sq-ft (0.254 acre) Total Rooftop area = (0.079 + 0.052) acre = 0.131 acre Total Driveway area = (0.041 + 0.038) acre = 0.079 acre Total Patio/Sidewalk area = (0.039 + 0.005) acre = 0.044 acre Total pervious area = area of disturbance – total impervious area (post-developed condition) Post-Developed: Q100-yr = 0.164064 cfs Change in site runoff: Post-developed condition Q100-yr - Pre-developed condition Q100-yr = 0.164064 cfs - 0.023263 cfs = 0.140801 cfs See Appendix B for WWHM2012 Project Report JDL Duplex Technical Information Report Page 11 Since the difference in post-developed and pre-developed flows are less than a 0.15 cfs difference (when modeled using 15-minute time steps), the project qualifies for an exception from the flow control facility requirement. Flow Control BMPs will be used to mitigate surface water runoff from new/replaced impervous surfaces. The parcel is smaller than 22,000 square feet. Therefore, the lot is subject to Section 1.2.9.2.1 Small Lot Bmp Requirements in the 2017 COR SWDM. Core Requirement #9: Feasibility of On-Site BMPs The feasibility and applicability of Small Lot BMP Requirements for TDA #1 are detailed below: 1. Full Dispersion was considered for use on the project but was determined to be infeasible because a native growth vegetated flow path segment, meeting minimum required length, is not available in the downstream vicinity of target impervious surfaces. 2. Full Infiltration was considered for use on the project to mitigate surface water runoff from target impervious surfaces but was determined to be infeasible due to the glacial till soil types on the property which are not conducive to infiltration. See Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW LLC. 3. Target surfaces not mitigated by requirements 1 & 2 of Section 1.2.9.2.2 were also evaluated for mitigation with one or more of the following BMPs: Full Infiltration, Limited Infiltration, Bioretention, and Permeable Pavement. A summary of the feasibility of these BMPs for use on the site is listed below: • Full Infiltration was considered for use on the project to mitigate surface water runoff from target impervious surfaces but was determined to be infeasible due to the glacial till soil types on the property which are not conducive to infiltration. See Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW LLC. • Limited Infiltration was considered for use on the project to mitigate surface water runoff from target impervious surfaces but was determined to be infeasible due to the glacial till soil types on the property which are not conducive to infiltration. See Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW LLC. • Bioretention was considered for use on the project to mitigate surface water runoff from target impervious surfaces but was determined to be infeasible due to the glacial till soil types on the property which are not conducive to infiltration. See Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW LLC. • Permeable Pavement was considered for use on the project to mitigate surface water runoff from target impervious surfaces but was determined to be infeasible due to the glacial till soil types on the property which are not conducive to infiltration. See Appendix A for the Infiltration Evaluation prepared by Earth Solutions NW LLC. 4. Target impervious surfaces not mitigated by Requirements 1, 2 and 3 of Section 1.2.9.2.2 were evaluated for mitigation using the Basic Dispersion BMP and determined to be feasible for a portion of the runoff. JDL Duplex Technical Information Report Page 12 • Flow control BMPs for Basic Dispersion will provide the required flow control for most of the target rooftop surface area. A 10-foot wide basic dispersion trench and two splash blocks for basic dispersion will provide the mitigation for 2,100 sq-ft of rooftop surface areas. 5. BMPs must be implemented, at minimum, for an impervious area equal to at least 10% of the site/lot for site/lot sizes up to 11,000 square feet and at least 20% of the site/lot for site/lot sizes between 11,000 and 22,000 square feet. For projects located in Zone 1 of the Aquifer Protection Area, these impervious area amounts must be doubled. Doubling of the minimum impervious area required for SECTION 1.2 CORE REQUIREMENTS 12/12/2016 2017 City of Renton Surface Water Design Manual 1-78 BMP implementation in Zone 1 of the Aquifer Protection Area is not required for projects located within 200 feet of a steep slope hazard area, landslide hazard, or erosion hazard area. If these minimum areas are not mitigated using feasible BMPs from Requirements 1, 2, 3, and 4 above, one or more BMPs from the following list are required to be implemented to achieve compliance. These BMPs must be implemented as part of the proposed project. • 20% of total lot area (post-developed lot area) = 13,363 sq-ft x 0.20 = 2,673 sq-ft minimum required to be mitigated with Flow Control BMPs. Provided mitigation using Flow Control BMPs: Total required mitigation = 2,673 sq-ft Mitigation provided: • One splash block for mitigation of 700 sq-ft of rooftop surface area. • Two 10-wide basic dispersion trenches for mitigation of 1,400 sq-ft total of rooftop surface area. • Sheet flow for basic dispersion of 663 sq-ft of driveway surface area. • Roof drains pass through a perforated pipe connection prior to discharge to public storm system. Total mitigation provided by Basic Dispersion BMPs = 2,763 sq-ft (greater than min. required) V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN The subject property contains an existing 18” CMP culvert which will be removed as part of the project and will be replaced with 6” ductile iron and 6” pvc pipe to direct flows into the City’s storm sewer system. Therefore, a conveyance analysis has been conducted to verify whether the replacement piping has sufficient capacity to drain the tributary upstream flows. See Appendix C for conveyance capacity calculations. VI. SPECIAL REPORTS AND STUDIES See Appendix A for Infiltration Evaluation prepared by Earth Solutions NW. JDL Duplex Technical Information Report Page 13 VII. OTHER PERMITS Building and Right of Way Use Permits are required. VIII. CSWPPP ANALYSIS AND DESIGN The potential for erosion within the site will be mitigated by use of erosion control measures during clearing, grading, and site development activities. Filter fences will be installed along the downhill perimeter of the site to protect adjacent properties from sediment-laden water. A rocked construction entrance will be installed at the entrance to the site to protect mud from entering the paved roadway. Stockpiles and exposed disturbed areas will be covered to protect from erosion and sediment runoff. Element 1: Mark Clearing Limits. All clearing, grading, sensitive areas, and buffers will be clearly marked in the field prior to construction in accordance to the plans and specifications. Prior to beginning land disturbing activities, including clearing and grading, clearly mark all clearing limits, sensitive areas and their buffers, and trees that are to be preserved within the construction area. These shall be clearly marked, both in the field and on the plans, to prevent damage and offsite impacts. Plastic, metal, or stake wire fence may be used to mark the clearing limits. Element 2: Establish Construction Access. Construction access will be provided for the site. Driveway re-alignment should be completed after all other construction is complete. Stabilize the construction access with rock per the stormwater plans if the driveway is disturbed. Access points shall be stabilized with a pad of quarry spalls, crushed rock, or equivalent BMP prior to traffic leaving the construction site to minimize the tracking of sediment onto all roads and accesses. Element 3: Control Flow Rates. Flow rates from the construction site are not expected to negatively impact the downstream corridor. A temporary sediment pond is not being proposed as part of this project, however other sediment retention BMPS are being proposed as part of Element 4. At all times, flow rates shall be controlled for this project. Natural drainage patterns shall be protected as much as possible during construction, and concentrated flow should not be permitted. Properties and waterways downstream from development sites shall be protected from erosion due to increases in the volume, velocity, and peak flow rate of stormwater runoff from the project site. Element 4: Install Sediment Controls. Silt fence should be used to protect all sensitive area slopes. Soils should be covered if not worked for 7 days during the dry season or 2 days during the wet season. The street should be swept each night or as required. If the minimum BMPs fail to retain sediment to the sight, additional BMPs will be used. JDL Duplex Technical Information Report Page 14 Element 5: Stabilize Soils. Soils shall be covered if not worked for 7 days during the dry season or 2 days during the wet season. Soil stockpiles will be covered unless worked. Soil stockpiles shall be located away from drain inlets and surface water discharge locations. Soil stockpiles shall be stabilized and covered as needed or removed to an approved disposal site. Soils shall be stabilized at the end of the shift before holidays or weekends if needed based on weather forecast. Element 6: Protect Slopes. The site does not appear to contain steep slopes and slope protection is not anticipated for this project. Element 7: Protect Drain Inlets. There are no existing catch basins in the immediate vicinity of the project. Element 8: Stabilize Channels and Outlets. Existing or proposed channels or drainage outlets are not components of this project, thus stabilization of these elements are not required. Element 9: Control Pollutants. Pollution generated from construction must be controlled at all times. Control of pollutants other than sediments includes the following: • All pollutants other than sediments shall be handled and disposed of in a manner that does not cause contamination of stormwater. • Cover, containment and protection from vandalism shall be provided for all chemicals, liquid products, petroleum products, and non-inert wastes present on the project site. • Maintenance and repair of heavy equipment and vehicles involving oil changes, hydraulic system drain down, solvent and de-greasing cleaning operations, fuel tank drain down and removal, and other activities which may result in discharge or spillage of pollutants to the ground or into stormwater runoff must be conducted using spill prevention measures, such as drip pans. Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. Emergency repairs may be performed on-site using temporary plastic placed beneath and, if raining, over the vehicle. • Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment system or to the sanitary sewer, if available. Element 10: Control De-Watering. De-watering is not anticipated for the site. In the event that dewatering is necessary, storm shall be treated such that sediment remains on site. This shall be done by routing the storm water through a straw filter, silt fence, and/or sediment trap. Element 11: Maintain BMPs. JDL Duplex Technical Information Report Page 15 BMPs shall be inspected monthly and after every significant storm event, Sediment shall be removed from the BMPs as necessary for them to continue operating at the required performance level. In the event that a BMPs has been damaged, it shall be replaced immediately. Element 12: Manage the Project. Construction activities shall be phased such that the impact to the area will be kept at a minimum. Coordination will occur with all utility agencies that are affected by this project. BMPs shall be inspected regularly and after each significant storm event. The Contractor will provide a Certified Erosion and Sediment Control Specialist. If for any reason a BMPs is not sufficient for the project, additional BMPs will be installed. IX. BOND QUANTITIES and DECLARATION of COVENANT Bond Quantities Not applicable. Declaration of Covenant Declaration of Covenant for maintenance will be required to be recorded by the Applicant after approval and prior to the issuance of permit. X. OPERATION AND MAINTENANCE MANUAL Operations and 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: ☒ splash blocks, rock pads, ☒ gravel filled trenches, ☐ sheet flow. 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. 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. JDL Duplex Technical Information Report Page 16 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. Drwn.CAM Checked AZS Date Nov.2017 Date 11/29/2017 Proj.No.5616 Plate 1 Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutionsNWLLC and Environmental Sciences Vicinity Map Benezra Renton King County (Renton),Washington Reference: King County,Washington Map 656 By The Thomas Guide Rand McNally 32nd Edition NORTH NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. SITE Drwn.CAM Checked AZS Date Nov.2017 Date 11/29/2017 Proj.No.5616 Plate 2 Earth Solutions NWLLC Geotechnical Engineering,Construction Monitoring EarthSolutionsNWLLC EarthSolutionsNWLLC and Environmental Sciences s.e.170th street 180thavenues.e.TP-2 TP-3 TP-1 NOTE:This plate may contain areas of color.ESNW cannot be responsible for any subsequent misinterpretation of the information resulting from black &white reproductions of this plate. NOTE:The graphics shown on this plate are not intended for design purposes or precise scale measurements,but only to illustrate the approximate test locations relative to the approximate locations of existing and /or proposed site features.The information illustrated is largely based on data provided by the client at the time of our study.ESNW cannot be responsible for subsequent design changes or interpretation of the data by others. LEGEND Approximate Location of ESNW Test Pit,Proj.No. ES-5616,Nov.2017 Subject Site Proposed Building TP-1 NOT -TO -SCALE NORTH Test Pit Location Plan Benezra Renton King County (Renton),Washington JDL Duplex Technical Information Report March 19, 2018 Page 15 Appendix B WWHM2012 Project Report WWHM2012 PROJECT REPORT default[42]3/27/2018 2:09:07 PM Page 2 General Model Information Project Name:default[42] Site Name: Site Address: City: Report Date:3/27/2018 Gage:Seatac Data Start:1948/10/01 00:00 Data End:2009/09/30 00:00 Timestep:15 Minute Precip Scale:1.00 Version Date:2016/02/25 Version:4.2.12 POC Thresholds Low Flow Threshold for POC1:100 Percent of the 100 Year High Flow Threshold for POC1:100 Year default[42]3/27/2018 2:09:07 PM Page 3 Landuse Basin Data Predeveloped Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Forest, Flat 0.301 Pervious Total 0.301 Impervious Land Use acre Impervious Total 0 Basin Total 0.301 Element Flows To: Surface Interflow Groundwater default[42]3/27/2018 2:09:07 PM Page 4 Mitigated Land Use Basin 1 Bypass:No GroundWater:No Pervious Land Use acre C, Lawn, Flat 0.14 Pervious Total 0.14 Impervious Land Use acre ROOF TOPS FLAT 0.075 DRIVEWAYS FLAT 0.048 SIDEWALKS FLAT 0.038 Impervious Total 0.161 Basin Total 0.301 Element Flows To: Surface Interflow Groundwater default[42]3/27/2018 2:09:07 PM Page 5 Routing Elements Predeveloped Routing default[42]3/27/2018 2:09:07 PM Page 6 Mitigated Routing default[42]3/27/2018 2:09:07 PM Page 7 Analysis Results POC 1 + Predeveloped x Mitigated Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.301 Total Impervious Area:0 Mitigated Landuse Totals for POC #1 Total Pervious Area:0.14 Total Impervious Area:0.161 Flow Frequency Method:Log Pearson Type III 17B Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.00885 5 year 0.013899 10 year 0.01676 25 year 0.019792 50 year 0.021667 100 year 0.023263 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.070672 5 year 0.093397 10 year 0.109383 25 year 0.130694 50 year 0.1474 100 year 0.164837 Annual Peaks Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.009 0.100 1950 0.011 0.092 1951 0.019 0.062 1952 0.006 0.046 1953 0.005 0.049 1954 0.008 0.057 1955 0.012 0.063 1956 0.010 0.063 1957 0.008 0.077 1958 0.009 0.056 default[42]3/27/2018 2:09:32 PM Page 8 1959 0.008 0.052 1960 0.013 0.065 1961 0.007 0.064 1962 0.005 0.050 1963 0.006 0.062 1964 0.008 0.057 1965 0.006 0.080 1966 0.006 0.048 1967 0.012 0.093 1968 0.008 0.097 1969 0.007 0.073 1970 0.006 0.066 1971 0.006 0.079 1972 0.015 0.093 1973 0.007 0.043 1974 0.007 0.075 1975 0.010 0.078 1976 0.007 0.058 1977 0.001 0.055 1978 0.006 0.068 1979 0.004 0.090 1980 0.014 0.106 1981 0.005 0.072 1982 0.011 0.111 1983 0.009 0.079 1984 0.006 0.053 1985 0.003 0.073 1986 0.015 0.063 1987 0.014 0.090 1988 0.005 0.052 1989 0.003 0.065 1990 0.028 0.162 1991 0.017 0.120 1992 0.007 0.053 1993 0.007 0.043 1994 0.002 0.043 1995 0.010 0.063 1996 0.021 0.077 1997 0.017 0.072 1998 0.004 0.064 1999 0.016 0.150 2000 0.007 0.071 2001 0.001 0.069 2002 0.007 0.099 2003 0.010 0.077 2004 0.012 0.138 2005 0.009 0.064 2006 0.010 0.058 2007 0.021 0.146 2008 0.027 0.118 2009 0.013 0.080 Ranked Annual Peaks Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0284 0.1620 2 0.0272 0.1498 3 0.0211 0.1456 default[42]3/27/2018 2:09:32 PM Page 9 4 0.0207 0.1380 5 0.0195 0.1203 6 0.0173 0.1180 7 0.0171 0.1109 8 0.0163 0.1064 9 0.0153 0.0998 10 0.0145 0.0988 11 0.0138 0.0974 12 0.0136 0.0928 13 0.0133 0.0926 14 0.0132 0.0918 15 0.0124 0.0901 16 0.0122 0.0900 17 0.0120 0.0803 18 0.0108 0.0797 19 0.0106 0.0787 20 0.0105 0.0787 21 0.0098 0.0777 22 0.0097 0.0774 23 0.0097 0.0768 24 0.0096 0.0766 25 0.0095 0.0747 26 0.0089 0.0728 27 0.0088 0.0727 28 0.0087 0.0724 29 0.0084 0.0722 30 0.0078 0.0709 31 0.0076 0.0693 32 0.0075 0.0681 33 0.0075 0.0659 34 0.0075 0.0650 35 0.0074 0.0646 36 0.0073 0.0641 37 0.0072 0.0638 38 0.0070 0.0636 39 0.0069 0.0632 40 0.0068 0.0630 41 0.0066 0.0626 42 0.0066 0.0625 43 0.0065 0.0619 44 0.0064 0.0617 45 0.0061 0.0581 46 0.0061 0.0577 47 0.0061 0.0575 48 0.0060 0.0568 49 0.0059 0.0559 50 0.0058 0.0547 51 0.0055 0.0530 52 0.0054 0.0526 53 0.0050 0.0521 54 0.0046 0.0519 55 0.0039 0.0500 56 0.0037 0.0495 57 0.0035 0.0485 58 0.0035 0.0457 59 0.0023 0.0433 60 0.0012 0.0429 61 0.0008 0.0427 default[42]3/27/2018 2:09:32 PM Page 10 default[42]3/27/2018 2:09:32 PM Page 11 Duration Flows The Facility PASSED Flow(cfs)Predev Mit Percentage Pass/Fail 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass default[42]3/27/2018 2:09:32 PM Page 12 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass 0.0233 0 0 0 Pass default[42]3/27/2018 2:09:32 PM Page 13 Water Quality Water Quality BMP Flow and Volume for POC #1 On-line facility volume:0 acre-feet On-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. Off-line facility target flow:0 cfs. Adjusted for 15 min:0 cfs. default[42]3/27/2018 2:09:32 PM Page 14 LID Report default[42]3/27/2018 2:09:33 PM Page 15 Model Default Modifications Total of 0 changes have been made. PERLND Changes No PERLND changes have been made. IMPLND Changes No IMPLND changes have been made. default[42]3/27/2018 2:09:33 PM Page 16 Appendix Predeveloped Schematic default[42]3/27/2018 2:09:34 PM Page 17 Mitigated Schematic default[42]3/27/2018 2:09:34 PM Page 18 Predeveloped UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 default[42].wdm MESSU 25 Predefault[42].MES 27 Predefault[42].L61 28 Predefault[42].L62 30 POCdefault[42]1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 10 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 10 C, Forest, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 10 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* 10 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO default[42]3/27/2018 2:09:34 PM Page 19 PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 10 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 10 0 4.5 0.08 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 10 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 10 0.2 0.5 0.35 6 0.5 0.7 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 10 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** END IWAT-PARM1 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS END IWAT-STATE1 default[42]3/27/2018 2:09:34 PM Page 20 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 10 0.301 COPY 501 12 PERLND 10 0.301 COPY 501 13 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC default[42]3/27/2018 2:09:34 PM Page 21 WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 501 OUTPUT MEAN 1 1 48.4 WDM 501 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 END MASS-LINK END RUN default[42]3/27/2018 2:09:34 PM Page 22 Mitigated UCI File RUN GLOBAL WWHM4 model simulation START 1948 10 01 END 2009 09 30 RUN INTERP OUTPUT LEVEL 3 0 RESUME 0 RUN 1 UNIT SYSTEM 1 END GLOBAL FILES <File> <Un#> <-----------File Name------------------------------>*** <-ID-> *** WDM 26 default[42].wdm MESSU 25 Mitdefault[42].MES 27 Mitdefault[42].L61 28 Mitdefault[42].L62 30 POCdefault[42]1.dat END FILES OPN SEQUENCE INGRP INDELT 00:15 PERLND 16 IMPLND 4 IMPLND 5 IMPLND 8 COPY 501 DISPLY 1 END INGRP END OPN SEQUENCE DISPLY DISPLY-INFO1 # - #<----------Title----------->***TRAN PIVL DIG1 FIL1 PYR DIG2 FIL2 YRND 1 Basin 1 MAX 1 2 30 9 END DISPLY-INFO1 END DISPLY COPY TIMESERIES # - # NPT NMN *** 1 1 1 501 1 1 END TIMESERIES END COPY GENER OPCODE # # OPCD *** END OPCODE PARM # # K *** END PARM END GENER PERLND GEN-INFO <PLS ><-------Name------->NBLKS Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 16 C, Lawn, Flat 1 1 1 1 27 0 END GEN-INFO *** Section PWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC *** 16 0 0 1 0 0 0 0 0 0 0 0 0 END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ***************************** PIVL PYR # - # ATMP SNOW PWAT SED PST PWG PQAL MSTL PEST NITR PHOS TRAC ********* default[42]3/27/2018 2:09:34 PM Page 23 16 0 0 4 0 0 0 0 0 0 0 0 0 1 9 END PRINT-INFO PWAT-PARM1 <PLS > PWATER variable monthly parameter value flags *** # - # CSNO RTOP UZFG VCS VUZ VNN VIFW VIRC VLE INFC HWT *** 16 0 0 0 0 0 0 0 0 0 0 0 END PWAT-PARM1 PWAT-PARM2 <PLS > PWATER input info: Part 2 *** # - # ***FOREST LZSN INFILT LSUR SLSUR KVARY AGWRC 16 0 4.5 0.03 400 0.05 0.5 0.996 END PWAT-PARM2 PWAT-PARM3 <PLS > PWATER input info: Part 3 *** # - # ***PETMAX PETMIN INFEXP INFILD DEEPFR BASETP AGWETP 16 0 0 2 2 0 0 0 END PWAT-PARM3 PWAT-PARM4 <PLS > PWATER input info: Part 4 *** # - # CEPSC UZSN NSUR INTFW IRC LZETP *** 16 0.1 0.25 0.25 6 0.5 0.25 END PWAT-PARM4 PWAT-STATE1 <PLS > *** Initial conditions at start of simulation ran from 1990 to end of 1992 (pat 1-11-95) RUN 21 *** # - # *** CEPS SURS UZS IFWS LZS AGWS GWVS 16 0 0 0 0 2.5 1 0 END PWAT-STATE1 END PERLND IMPLND GEN-INFO <PLS ><-------Name-------> Unit-systems Printer *** # - # User t-series Engl Metr *** in out *** 4 ROOF TOPS/FLAT 1 1 1 27 0 5 DRIVEWAYS/FLAT 1 1 1 27 0 8 SIDEWALKS/FLAT 1 1 1 27 0 END GEN-INFO *** Section IWATER*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # ATMP SNOW IWAT SLD IWG IQAL *** 4 0 0 1 0 0 0 5 0 0 1 0 0 0 8 0 0 1 0 0 0 END ACTIVITY PRINT-INFO <ILS > ******** Print-flags ******** PIVL PYR # - # ATMP SNOW IWAT SLD IWG IQAL ********* 4 0 0 4 0 0 0 1 9 5 0 0 4 0 0 0 1 9 8 0 0 4 0 0 0 1 9 END PRINT-INFO IWAT-PARM1 <PLS > IWATER variable monthly parameter value flags *** # - # CSNO RTOP VRS VNN RTLI *** 4 0 0 0 0 0 5 0 0 0 0 0 8 0 0 0 0 0 END IWAT-PARM1 default[42]3/27/2018 2:09:34 PM Page 24 IWAT-PARM2 <PLS > IWATER input info: Part 2 *** # - # *** LSUR SLSUR NSUR RETSC 4 400 0.01 0.1 0.1 5 400 0.01 0.1 0.1 8 400 0.01 0.1 0.1 END IWAT-PARM2 IWAT-PARM3 <PLS > IWATER input info: Part 3 *** # - # ***PETMAX PETMIN 4 0 0 5 0 0 8 0 0 END IWAT-PARM3 IWAT-STATE1 <PLS > *** Initial conditions at start of simulation # - # *** RETS SURS 4 0 0 5 0 0 8 0 0 END IWAT-STATE1 END IMPLND SCHEMATIC <-Source-> <--Area--> <-Target-> MBLK *** <Name> # <-factor-> <Name> # Tbl# *** Basin 1*** PERLND 16 0.14 COPY 501 12 PERLND 16 0.14 COPY 501 13 IMPLND 4 0.075 COPY 501 15 IMPLND 5 0.048 COPY 501 15 IMPLND 8 0.038 COPY 501 15 ******Routing****** END SCHEMATIC NETWORK <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** COPY 501 OUTPUT MEAN 1 1 48.4 DISPLY 1 INPUT TIMSER 1 <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # #<-factor->strg <Name> # # <Name> # # *** END NETWORK RCHRES GEN-INFO RCHRES Name Nexits Unit Systems Printer *** # - #<------------------><---> User T-series Engl Metr LKFG *** in out *** END GEN-INFO *** Section RCHRES*** ACTIVITY <PLS > ************* Active Sections ***************************** # - # HYFG ADFG CNFG HTFG SDFG GQFG OXFG NUFG PKFG PHFG *** END ACTIVITY PRINT-INFO <PLS > ***************** Print-flags ******************* PIVL PYR # - # HYDR ADCA CONS HEAT SED GQL OXRX NUTR PLNK PHCB PIVL PYR ********* END PRINT-INFO HYDR-PARM1 RCHRES Flags for each HYDR Section *** default[42]3/27/2018 2:09:34 PM Page 25 # - # VC A1 A2 A3 ODFVFG for each *** ODGTFG for each FUNCT for each FG FG FG FG possible exit *** possible exit possible exit * * * * * * * * * * * * * * *** END HYDR-PARM1 HYDR-PARM2 # - # FTABNO LEN DELTH STCOR KS DB50 *** <------><--------><--------><--------><--------><--------><--------> *** END HYDR-PARM2 HYDR-INIT RCHRES Initial conditions for each HYDR section *** # - # *** VOL Initial value of COLIND Initial value of OUTDGT *** ac-ft for each possible exit for each possible exit <------><--------> <---><---><---><---><---> *** <---><---><---><---><---> END HYDR-INIT END RCHRES SPEC-ACTIONS END SPEC-ACTIONS FTABLES END FTABLES EXT SOURCES <-Volume-> <Member> SsysSgap<--Mult-->Tran <-Target vols> <-Grp> <-Member-> *** <Name> # <Name> # tem strg<-factor->strg <Name> # # <Name> # # *** WDM 2 PREC ENGL 1 PERLND 1 999 EXTNL PREC WDM 2 PREC ENGL 1 IMPLND 1 999 EXTNL PREC WDM 1 EVAP ENGL 0.76 PERLND 1 999 EXTNL PETINP WDM 1 EVAP ENGL 0.76 IMPLND 1 999 EXTNL PETINP END EXT SOURCES EXT TARGETS <-Volume-> <-Grp> <-Member-><--Mult-->Tran <-Volume-> <Member> Tsys Tgap Amd *** <Name> # <Name> # #<-factor->strg <Name> # <Name> tem strg strg*** COPY 1 OUTPUT MEAN 1 1 48.4 WDM 701 FLOW ENGL REPL COPY 501 OUTPUT MEAN 1 1 48.4 WDM 801 FLOW ENGL REPL END EXT TARGETS MASS-LINK <Volume> <-Grp> <-Member-><--Mult--> <Target> <-Grp> <-Member->*** <Name> <Name> # #<-factor-> <Name> <Name> # #*** MASS-LINK 12 PERLND PWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 12 MASS-LINK 13 PERLND PWATER IFWO 0.083333 COPY INPUT MEAN END MASS-LINK 13 MASS-LINK 15 IMPLND IWATER SURO 0.083333 COPY INPUT MEAN END MASS-LINK 15 END MASS-LINK END RUN default[42]3/27/2018 2:09:34 PM Page 26 Predeveloped HSPF Message File default[42]3/27/2018 2:09:34 PM Page 27 Mitigated HSPF Message File default[42]3/27/2018 2:09:34 PM Page 28 Disclaimer Legal Notice This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2018; All Rights Reserved. Clear Creek Solutions, Inc. 6200 Capitol Blvd. Ste F Olympia, WA. 98501 Toll Free 1(866)943-0304 Local (360)943-0304 www.clearcreeksolutions.com JDL Duplex Technical Information Report Page 19 Appendix C Conveyance Capacity Calculations Subbasin Flows - 25-year Rational Method Design Storm a R b R PR 25yr 2.66 0.65 3.4 Subbasin Subbasin Subbasin Subbasin Area Imperv.C imperv Perv.Cperv T c (min)Q25 (CFS) 1 0.0938 acres 0.0085 acres 0.90 0.0852 acres 0.25 5 0.09 Surface Coverage 372 sq-ft Gravel Driveway (impervious) 3,713 sq-ft Lawn (pervious) MANNING'S EQUATION FOR PIPE FLOW Project: JDL Duplex Location:City of Renton By:Dan Davis Date:11/13/2018 Chk. By:Tom Redding Date:11/13/2018 INPUT D=6 inches d=5.5 inches Mannings Formula n=0.012 mannings coeff q=67.1 degrees Q=(1.486/n)ARh 2/3S1/2 S=0.005 slope in/in R=A/P A=cross sectional area P=wetted perimeter V=(1.49/n)Rh 2/3S1/2 S=slope of channel Q=V x A n=Manning's roughness coefficient Solution to Mannings Equation Area,ft2 Wetted Perimeter, ft Hydraulic Radius, ft velocity ft/s flow, cfs Conc 0.012 0.19 1.28 0.15 2.44 0.46 LCPE 0.012 Lined PP 0.012 CMP 0.024 Unlined CPE 0.024 PVC 0.011 Ductile Iron 0.012 Solid wall HDPE 0.009 Capacity check 0.46 cfs ≥ 0.09 cfs  Manning's n-values d q D Clear Data Entry Cells