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Home My WebLink AboutTIR_4165 TECHNICAL INFORMATION REPORT Hanger Addition for Bosair, LLC 289 East Perimeter Road Renton, WA 98057 Prepared for: Bosair, LLC 289 East Perimeter Road Renton, WA 98057 February 11, 2021 Our Job No. 15559 02/11/2021 15559.006 TABLE OF CONTENTS 1.0 PROJECT OVERVIEW 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 3.0 OFF-SITE ANALYSIS 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 6.0 SPECIAL REPORTS AND STUDIES 7.0 OTHER PERMITS 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN ANALYSIS AND DESIGN 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 10.0 OPERATIONS AND MAINTENANCE MANUAL Figure 1 – TIR Worksheet Figure 2 – Vicinity Map Figure 3 – Drainage Basins, Subbasins, and Site Characteristics Figure 4 – Soils Tab 1.0 1.0 PROJECT OVERVIEW 15559.006 1.0 PROJECT OVERVIEW The site is located within a portion of the northeast quarter of the northeast quarter of Section 18, Township 23 North, Range 5 East, Willamette Meridian, City of Renton, King County, Washington and comprises approximately 1.856 acres. More particularly, the site is located at 289 East Perimeter Road within the City of Renton and on a portion of the Renton Municipal Airport. The attached vicinity map gives the exact location of the project site. The proposal for this development is to construct an addition to the existing eastern hanger with a new sewer service. The existing area or work is entirely impervious surface, consisting of buildings and pavement. Under the proposed scope of work, approx. 5,900 sq. ft. of impervious surface will be removed and replaced to accommodate the new hanger addition and relocated utilities. This project does not propose flow control nor is it required for this project site. There is an existing conveyance system that routes and drains directly into the Cedar River located northeast of and immediately across East Perimeter Road from the project site. Since this project site is located on a portion of the Renton Municipal Airport, it is relatively flat in nature. It is anticipated that minimal grading will occur and site grades will stay much the way they are. Please see the existing and proposed site land coverage table on the following pages of this report for a complete description of the site land coverage. 15559.006 EXISTING AND PROPOSED SITE LAND COVERS Existing condition of area to be modified: Existing impervious to be replaced = 5,915 sf Total = 5,704 sf Proposed condition of area to be modified: New building = 3,800 sf Replaced pavement = 2,115 sf Total = 5,915 sf FIGURE 1 – TIR WORKSHEET CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Land Use (e.g., Subdivision / Short Subd.)  Building (e.g., M/F / Commercial / SFR)  Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed ____________________________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified ____________________________________ __________________ Bosair, LLC 289 East Perimeter Road Zayin Wall Barghausen Consulting Engineers, Inc. 425-251-6222 Bosair, LLC 23 N 5 E 18 289 East Perimeter Road Renton, WA 98057 X X X REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-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 ______________________  _____________________________________ Renton Cedar River Peak Rate Flow Control Standard X X 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: _________________________ Urban Land 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 _______________________________ X X X X X X Oil/water separator 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 9/28/2020 FIGURE 2 –VICINITY MAP FIGURE 3 – DRAINAGE BASINS, SUBBASINS, AND SITE CHARACTERISTICS EXISTING CONDITIONS BOSAIR, LLCNE1/4, OF THE NE1/4 OF SEC. 18,TWP 23 N., RGE 5 EAST, W. M.CITY OF RENTON KING COUNTY WASHINGTONAAANNNNNNN FORBOSAIR, LLC289 E PERIMETER ROADRENTON, WA 98057BCE#15559 - BOSAIR, LLC --BOSAIR, LLC -SCALE: 1"=20'GRADING AND DRAINAGE PLANNEW BUILDING ADDITION= 3,800 +/- SQ.FT.TOTAL REPLACEDPAVEMENT = 2,115 +/- SQ.FT. FIGURE 4 – SOILS BOSAIR, LLC Tab 2.0 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 15559.006 2.0 CONDITIONS AND REQUIREMENTS SUMMARY Analysis of the Eight Core Requirements. Core Requirement No. 1 – Discharge at the Natural Location: This project will still discharge into the same conveyance system it does under existing conditions to the Cedar River immediately adjacent to the project site. Core Requirement No. 2 – Off-Site Analysis: No off-site analysis is required for this project as it is an already developed site and the City is aware of the downstream drainage course from this project site. In addition, the site has direct discharge into the Cedar River at the northeast side of the project site. Core Requirement No. 3 – Flow Control: There will be the same impervious surface for the project site after the project is constructed than there is under existing conditions. Since the site lies in the peak rate flow control standard of the City of Renton, this project is exempt from flow control as runoff leaving the project site is the same as it is under existing conditions. Core Requirement No. 4 – Conveyance System: New roof drains will be routed to the existing roof drainage system. The developed area will continue to drain per the existing conditions, and no conveyance system modifications are proposed. Core Requirement No. 5 – Erosion and Sediment Control: ESC measures will be followed for this project site, including specifying clearing limits and providing perimeter protection along the downstream perimeter of the project site. Also, catch basin protection being instituted to prevent sediment from being discharged into the downstream drainage course. Bare ground exposure will be very limited at any one time on the project site during construction, due to the fact that this is a re-development project. Core Requirement No. 6 – Maintenance and Operations: This project will concur with all maintenance and operations requirements of the City of Renton. An Operations and Maintenance Manual is included in Section 10.0 of this report. Core Requirement No. 7 – Financial Guarantees and Liabilities: This project will concur with all financial guarantees and liability requirements of the City of Renton for projects of this nature. Core Requirement No. 8 – Water Quality: This project will have less pollution generating impervious surface than under existing conditions. Water quality was provided in the form of coalescing plate oil/water separators for treatment for oil prior to discharge into the downstream drainage system at the time the existing building was constructed. Core Requirement No. 9 - On-Site BMPS: There will be the same impervious surface for the project site after the project is constructed than there is under existing conditions, and the site lies in the peak rate flow control standard of the City of Renton. This project site lies within a Zone 1 aquifer protection area. As such, no infiltration of other on-site BMPs are proposed with this project. Analysis of the Six Special Requirements: Special Requirement No. 1 – Other Adopted Area-Specific Requirements: This project lies within the City of Renton and must meet their 2017 Surface Water Design Manual. The project lies within the peak rate flow control standard and is in compliance with this standard. Special Requirement No. 2 – Flood Hazard Area Delineation: This project is adjacent to a flood hazard area for a river; therefore, the flood way is shown on the plan. Special Requirement No. 3 – Flood Protection Facilities: This project does not rely on an existing flood protection facility, nor is it required to construct a flood protection facility. 15559.006 Special Requirement No. 4 – Source Control: Source controls are being applied to this project site by educating the owner about the proper use of pesticides and fertilizers on the landscaping. In addition, this parking lot will be swept up regularly and the trash enclosure will be covered to provide source control protection. Special Requirement No. 5 – Oil Control: To the best of our knowledge, this project site does not exhibit the characteristics of a high-use site. The project does not have an expected average daily traffic count equal to or greater than 100 vehicles per 1,000 square feet of gross building area. The project does not store or transfer in excess of 1,500 gallons of petroleum per year. The project does not use, store, or maintain a fleet of over 25 vehicles that are over 10 tons net weight. However, oil control for the stormwater conveyance system was provided when the existing building was constructed in the form of coalescing plate oil/water separators to treat for oil as required by the City of Renton. Special Requirement No. 6 – Aquifer Protection Area: This project site lies within a Zone 1 aquifer protection area. As such, no infiltration is proposed with this project. Tab 3.0 3.0 OFF-SITE ANALYSIS 15559.006 3.0 OFF-SITE ANALYSIS No off-site analysis is required for this project site, as the site discharges almost immediately into the Cedar River located across East Perimeter Road. There are no problems associated with this project's downstream drainage course. Runoff is collected by onsite catch basins before discharging to an existing oil/water separator through 25 LF of 12-inch PVC to the northwest into a Type 1 catch basin. Runoff then courses northeasterly through 107 LF of existing 12-inch storm drain to a Type 2 48- inch manhole, then again northeasterly through 110 LF of existing 12-inch storm drain to a Type 1 catch basin on the east side of East Perimeter Road. Runoff courses from this catch basin for 20 feet (approximately) directly into the Cedar River. The Cedar River ultimately drains into Lake Washington. BOSAIR, LLC FEMA/FLOOD PLAIN MAP 15559.006 FLOODPLAIN Please refer to the attached document indicating that the 100-year flood plain is contained within the river and the project site is located outside of the flood plain. BOSAIR, LLC BOSAIR, LLC BOSAIR, LLC Tab 4.0 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 15559.006 4.0 FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN A. Existing Site Hydrology Under existing conditions, runoff from pollution generating impervious surfaces drains to an existing oil/water separator. The existing project area is completely impervious. B. Developed Site Hydrology Under developed conditions, there will be approximately 5,900 square feet of replaced impervious surface. A new approximately 3,800 square foot building addition will be constructed with the roof drains connecting to the existing building roof drainage collection system. Runoff from outside the building will continue to drain per the existing conditions and routed to an existing oil/water separator prior to discharge to the downstream conveyance system. C. Performance Standards The area-specific flow control standards determined from the City of Renton Flow Control Applications Map is the Peak Rate Flow Control Standard matching the existing conditions. Flow control is not required since the proposed project is discharging the same runoff under proposed conditions as under existing conditions. The applicable conveyance system capacity standards are not applicable as the entire site is being conveyed adequately under existing conditions and the proposed project will have the same impervious surface draining to the existing conveyance system. D. Flow Control Systems As mentioned previously, flow control is not a requirement for this project site. E. Water Quality Systems As mentioned previously, oil control was provided when the original building was constructed in the form of a coalescing plate oil/water separator which treats runoff from pollution generating impervious surface outside the buildings. Tab 5.0 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN 15559.006 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN As mentioned previously, conveyance is not an issue for this project site, as there is already an existing conveyance system that will be utilized under proposed conditions on the site with the same amount of runoff draining to it. Tab 6.0 6.0 SPECIAL REPORTS AND STUDIES 15559.006 6.0 SPECIAL REPORTS AND STUDIES There are no known special reports and studies to the best of our knowledge. Tab 7.0 7.0 OTHER PERMITS 15559.006 7.0 OTHER PERMITS Other permits for this project include a Right-of-Way Use Permit, Commercial Building Permit, Clear and Grade Permit, Waterline Extension Permit, and Sanitary Side Sewer Permit. Tab 8.0 8.0 CONSTRUCTION STORMWATER POLLUTION PREVENTION PLAN ANALYSIS AND DESIGN 15559.006 8.0 CSWPPP ANALYSIS AND DESIGN A CSWPPP will be provided with the final version of this report. Tab 9.0 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 15559.006 9.0 BOND QUALITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT Tab 10.0 10.0 OPERATIONS AND MAINTENANCE MANUAL 15559.006 10.0 OPERATIONS AND MAINTENANCE MANUAL An operations and maintenance manual will be provided with the final version of this report.