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RS_Brotherton_Dealership_Drainage_Technical_Information_Report_230317_v3
Brotherton Dealership Dealership Construction and Expansion Technical Information Report Prepared for: Brotherton Cadillac 215 SW 12th Street Renton, WA 98057 Contact: Brad Brotherton Phone: (425) 336-1089 Prepared by: Sitts & Hill Engineers, Inc. 4815 Center Street Tacoma, Washington 98409 Contact: Don Davis, P.E. Phone: (253) 474-9449 July 2022 Revised: March 2023 S&H Job Number 19,480 DEVELOPMENT ENGINEERING NJanders 05/08/2023 SURFACE WATER UTILITY JFarah 05/08/2023 Brotherton Dealership Dealership Construction and Expansion Technical Information Report Prepared for: Brotherton Cadillac 215 SW 12th Street Renton, WA 98057 Contact: Brad Brotherton Phone: (425) 336-1089 Prepared by: Sitts & Hill Engineers, Inc. 4815 Center Street Tacoma, Washington 98409 Contact: Don Davis, P.E. Phone: (253) 474-9449 IN COMPLIANCE WITH CITY OF RENTON STANDARDS July 2022 Revised: March 2023 S&H Job Number 19,480 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT i TABLE OF CONTENTS 1.0 PROJECT OVERVIEW ............................................................................................................... 4 1.1 Scope ................................................................................................................................................................ 4 1.2 Existing Conditions ........................................................................................................................................ 5 1.3 Proposed Conditions ..................................................................................................................................... 7 2.0 Conditions and Requirements Summary ............................................................................. 10 2.1 Discussion of Core and Special Requirements ........................................................................................ 10 2.1.1 Core Requirement #1: Discharge at the Natural Location .............................................................. 10 2.1.2 Core Requirement #2: Off-site Analysis ............................................................................................ 10 2.1.3 Core Requirement #3: Flow Control ................................................................................................... 10 2.1.4 Core Requirement #4: Conveyance System ..................................................................................... 11 2.1.5 Core Requirement #5: Erosion and Sediment Control .................................................................... 11 2.1.6 Core Requirement #6: Maintenance and Operations ...................................................................... 11 2.1.7 Core Requirement #7: Financial Guarantees and Liability ............................................................. 11 2.1.8 Core Requirement #8: Water Quality ................................................................................................. 11 2.1.9 Core Requirement #9: On-site BMPs ................................................................................................. 11 2.1.10 Special Requirement #1: Other Adopted Area-Specific Requirements ...................................... 13 2.1.11 Special Requirement #2: Flood Hazard Area Delineation ............................................................ 13 2.1.12 Special Requirement #3: Flood Protection Facilities ..................................................................... 13 2.1.13 Special Requirement #4: Source Control ........................................................................................ 13 2.1.14 Special Requirement #5: Oil Control ................................................................................................ 14 2.1.15 Special Requirement #6: Aquifer Protection Areas ....................................................................... 14 3.0 OFF-SITE ANALYSIS ............................................................................................................... 19 3.1 Define and Map the Study Area ................................................................................................................ 19 3.2 Resource Review .......................................................................................................................................... 25 3.3 Field Inspection ............................................................................................................................................ 25 3.4 Drainage System Description and Problem Descriptions ..................................................................... 25 3.5 Mitigation of Existing or Potential Problems ......................................................................................... 26 4.0 FLOW CONTROL, LID, AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ..... 27 4.1 Existing Site Hydrology ............................................................................................................................... 27 4.2 Developed Site Hydrology ......................................................................................................................... 27 4.3 Performance Standards .............................................................................................................................. 27 4.4 Flow Control System ................................................................................................................................... 28 4.4.1 Flow Control Exemptions Check ......................................................................................................... 28 4.4.2 Flow Control Area .................................................................................................................................. 28 4.4.3 Flow Control Area Requirements and Exceptions ........................................................................... 28 4.4.4 Identify Applicable Flow Control BMPs per Core Requirement #9 ................................................ 28 4.5 Water Quality ............................................................................................................................................... 29 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN ............................................................. 31 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT ii 6.0 SPECIAL REPORTS AND STUDIES ...................................................................................... 33 7.0 OTHER PERMITS ..................................................................................................................... 34 8.0 CSWPPP ANALYSIS AND DESIGN ....................................................................................... 35 9.0 BOND QUANTITIES and R/D FACILITY SUMMARIES ........................................................ 36 9.1 Bond Quantities ........................................................................................................................................... 36 9.2 Facility Summaries ....................................................................................................................................... 36 10.0 OPERATIONS AND MAINTENANCE MANUAL .................................................................. 37 10.1 Purpose ....................................................................................................................................................... 37 10.2 Permanent Facilities Description ............................................................................................................ 37 10.3 Discussion of Maintenance ...................................................................................................................... 37 10.4 Maintenance Frequency ........................................................................................................................... 38 10.5 Annual Cost Estimate ................................................................................................................................ 38 TABLE OF APPENDICES A.1 TIR Worksheet ........................................................................................................................ 41 A.2 Bond Quantity Worksheet ..................................................................................................... 48 A.3 Existing and Proposed Surface Coverage Exhibits .......................................................... 49 A.4 Site Historical Aerial Photography ...................................................................................... 54 A.5 Stormwater Engineering Calculations ................................................................................ 62 A.6 Geotechnical Engineering Report........................................................................................ 91 A.7 WWHM Reports ...................................................................................................................... 92 A.8 SSA Reports.......................................................................................................................... 123 A.9 Water Quality GULDs ........................................................................................................... 143 A.10 Flygt NP 3085 SH Technical Information ........................................................................ 160 TABLE OF FIGURES Figure 1 – Site Location Map – Proposed Building ...................................................................................... 5 Figure 2 – Site Location Map – Proposed Addition ...................................................................................... 6 Figure 3 – Drainage Review Flow Chart – Proposed Building ................................................................. 15 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT iii Figure 4 – Drainage Review Flow Chart – Proposed Addition ................................................................. 16 Figure 5 – FEMA Map – Proposed Building ................................................................................................ 17 Figure 6 – FEMA Map – Proposed Addition ................................................................................................ 18 Figure 7 - Downstream Flow Path – Proposed Building ........................................................................... 19 Figure 8 – Downstream Flow Path – Proposed Addition .......................................................................... 20 Figure 9 – Topographic Survey ..................................................................................................................... 24 Figure 10- City of Renton Flow Control Application Map .......................................................................... 30 Figure 11 - WWHM Stormfall for the Eastern BioPod................................................................................ 31 Figure 12 - WWHM Stormfall Tributary to Western BioPod ...................................................................... 32 Figure 13 – TIR Worksheet ........................................................................................................................... 47 Figure 14 - Predeveloped conditions for the Cadillac site used for Water Quality ................................ 62 Figure 15 - Developed conditions for the Cadillac site used for Water Quality ..................................... 63 Figure 16 – WWHM 2012 Flow Frequency calculations for the Cadillac site ........................................ 64 Figure 17 - WWHM 2012 Water Quality calculations for the Cadillac site ............................................. 65 Figure 18 - Predeveloped conditions for the Buick-GMC site used for Water Quality .......................... 66 Figure 19 - Developed conditions for the Buick-GMC site used for Water Quality ............................... 66 Figure 20 - WWHM 2012 Flow Frequency calculations for the Buick-GMC site ................................... 68 Figure 21 - WWHM 2012 Water Quality calculations for the Buick-GMC site ....................................... 68 Figure 22 - WWHM 2012 Flow Frequency Calculations for the combined project area ...................... 69 Figure 23 - Pump Operation Envelope......................................................................................................... 74 Figure 24 - Minor Loss Nomograph .............................................................................................................. 75 Figure 25 – Minimum Pump Curve Head (ft) vs Flow (cfs) ....................................................................... 76 Figure 26 - Difference between upper and lower pump curve head (ft) vs flow (cfs) ........................... 77 Figure 27 - Storage curve for 5 StormCapture units .................................................................................. 78 Figure 28 - 2-year Total System Inflow, Pump Flow, and System Outflow vs Time ............................. 79 Figure 29 – 2-year Water Depth and Storage Volume for StormCapture units and lift station ........... 80 Figure 30 - 10-year Storage Depth, Pump Flow, and System Outflow vs Time .................................... 81 Figure 31 - 10-year Water Depth and Storage Volume for StormCapture units and lift station .......... 82 Figure 32 - 100-year Storage Depth, Pump Flow, and System Outflow vs Time .................................. 83 Figure 33 – 100-year Water Depth and Storage Volume for StormCapture units and lift station ....... 84 TABLE OF TABLES Table 1. Existing and Developed Condition Description – Proposed Building ........................................ 8 Table 2. Existing and Developed Condition Description – Proposed Addition ........................................ 9 Table 3. Pump Total Dynamic Head vs Flow (gpm) .................................................................................. 73 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 4 1.0 PROJECT OVERVIEW 1.1 Scope This Technical Information Report (TIR) addresses improvements associated with the proposed building located at 201 SW 12th Street, Renton, WA (Parcel Nos. 3340402780, 3340402805, 3340402880, and 3340402925) and the proposed building addition at 215 SW 12th Steet, Renton, WA (Parcel Nos. 3340402820, 3340402850, 3340402860, 3340402870, and 3340402885). Please see Figure 1 for the Site Location Map of the proposed building and Figure 2 for the Site Location Map of the proposed building addition. This construction is proposed to serve as a stand-alone Cadillac automotive dealership for Brotherton Cadillac and additional shop space for the existing Brotherton Buick-GMC dealership. The new dealership will replace existing residential development with driveway connections to SW 12th Street and the neighboring Brotherton Buick-GMC dealership via the SW 13th Street former right of way. The addition will replace part of the existing parking lot without changing the number or locations of entrances. This Technical Information Report has been prepared in accordance with the 2017 City of Renton Stormwater Design Manual (SWDM). A copy of the TIR Worksheet, which provides basic information about the scope of this project, is included with this report in Appendix A.1. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 5 Figure 1 – Site Location Map – Proposed Building 1.2 Existing Conditions The subject sites are located on nine parcels, zoned as Commercial Arterial (CA), with a combined area of 2.84 acres of developed land. The sites, as depicted on the topographical survey, are relatively flat. The original dealership was graded with depressions to direct stormwater into on-site catch basins. The privately owned stormwater system extends upstream to the east, collecting stormwater runoff from two more parking areas to the east and north of the subject property before discharging into the system of the Brotherton automotive dealership. The existing sites consist of residential development, a Cadillac, Buick, and GMC dealership, and associated parking. Based on historical aerial photographs and the King County Assessor’s Website, the site appeared to be residential housing as early as 1951. One of the residential BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 6 lots was emptied between May of 2013 and July of 2014. Another was replaced with parking between May of 2017 and May of 2018 and replaced with a fenced, gravel parking area. See Appendix A.4, which includes a series of aerial photographs dating back to July, 1990. Upon a visual examination of existing site conditions, stormwater runoff is either collected in a private catch basin located on Parcel 3340402880, flows onto the neighboring Brotherton Cadillac automotive dealership, or flows onto SW 12th St or SW 13th St to be collected by a public catch basin. Stormwater collected in the private catch basin, or that flows onto the neighboring dealership, is conveyed through an existing private wet vault water quality and detention vault that discharges into the public stormwater system on the southwest corner of the dealership. Stormwater in a portion of the southwest corner of the existing dealership is collected into a system that conveys it west across Maple Ave into a neighboring private stormwater system. Based upon a review of available information from the City of Renton, we are not aware of any Figure 2 – Site Location Map – Proposed Addition BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 7 capacity problems with the existing drainage facilities adjacent to this area. The City of Renton’s Public Works Maps combined with King County GIS together indicate the site is not located within or near any critical areas. In addition, it is located within the Peak Rate Flow Control Standard Zone. 1.3 Proposed Conditions The purpose of site improvements for this project is to create a new stand-alone automotive dealership for Brotherton Cadillac, and an addition for the existing automotive dealership. A shared access will be constructed between the new construction and the existing building that connects with the existing rear entrance to the existing building. The project proposes grading, paving, and drainage (water quality facilities, detention, and conveyance piping) improvements for on-site and off-site areas. See Table 1 for a description of existing and proposed surface conditions of the proposed building and Table 2 for a description of existing and proposed surfaces for the proposed addition. Over 50% of the stormwater generated on-site will be from a pollution-generating surface in a commercial area and thus stormwater runoff generated will be subject to enhanced basic water quality treatment before being conveyed to the conveyance system located within the City’s right-of-way. Treatment for the proposed building and addition will be provided by Oldcastle BioPod Biofilters. All proposed surfacing in the project area is considered new or replaced surfacing. Please see Appendix A.5 for the sub-basin exhibit as it outlines the tributary area for each catch basin. ADA accessible ramps will also be installed at the adjacent corners, at the intersection of Maple Ave SW and SW 12th Street. These ramps are not included in the surface coverages discussed in this report as they replace impervious surface with impervious surface and will have no noticeable impact on the public stormwater system. Please see Appendix A.3 for Existing and Proposed Surface Coverage Exhibits. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 8 Table 1. Existing and Developed Condition Description – Proposed Building Description On-site Off-site Total Existing Conditions Total Project Area (ft2) 51,250 6,710 57,960 Existing hard surface (ft2) 22,250 4,950 27,200 Existing landscaping/lawn area (ft2) 29,000 1,760 30,760 Total Project Area (ft2) 51,250 6,710 57,960 Amount of new hard surface (ft2) 25,350 400 25,750 Amount of new pollution generating hard surface (PGHS) (ft2) 16,850 400 17,250 Amount of replaced hard surface (ft2) 22,250 4,950 27,200 Amount of replaced PGHS (ft2) 14,450 4,950 19,400 Amount of new plus replaced hard surface (ft2) 47,600 5,350 52,950 Amount of new plus replaced PGHS (ft2) 31,300 5,350 36,650 Amount of existing hard surfaces converted to vegetation/landscaping (ft2) 0 0 0 Amount of Land Disturbed (ft2) 51,250 6,710 57,960 Native Vegetation to Pasture (acres) 0 0 0 Existing vegetation area to remain (ft2) 3,650 1,360 5,010 Existing hard surface to remain unaltered (ft2) 0 0 0 Value of proposed improvements ($) $8.3M 0 $8.3M Amount to be Graded/Approx. FILL (CY) 519 0 519 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 9 Table 2. Existing and Developed Condition Description – Proposed Addition Description On-site Off-site Total Existing Conditions Total Project Area (ft2) 13,630 1,850 15,480 Existing hard surface (ft2) 10,630 0 10,630 Existing landscaping/lawn area (ft2) 3,000 1,850 4,850 Developed Conditions Total Project Area (ft2) 13,630 1,850 15,480 Amount of new hard surface (ft2) 4,660 930 5,590 Amount of new pollution generating hard surface (PGHS) (ft2) 240 930 1,170 Amount of replaced hard surface (ft2) 6,250 0 6,250 Amount of replaced PGHS (ft2) 6,250 0 6,250 Amount of new plus replaced hard surface (ft2) 10,910 930 11,840 Amount of new plus replaced PGHS (ft2) 6,490 930 7,420 Amount of existing hard surfaces converted to vegetation/landscaping (ft2) 0 0 0 Amount of Land Disturbed (ft2) 13,630 1,850 15,480 Native Vegetation to Pasture (acres) 0 0 0 Existing vegetation area to remain (ft2) 2,720 920 3,640 Existing hard surface to remain unaltered (ft2) 0 0 0 Value of proposed improvements ($) $1.3M 0 $1.3M Amount to be Graded/Approx. FILL (CY) 35 0 35 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 10 2.0 CONDITIONS AND REQUIREMENTS SUMMARY 2.1 Discussion of Core and Special Requirements These are two Commercial Arterial (CA) projects that each add more than 2,000 square feet of new and replaced impervious surface. Therefore, the projects are subject to a full drainage review and must satisfy all core requirements (1-9) and all special requirements (1-6) of the 2017 City of Renton Stormwater Design Manual (SWDM). See Figure 3 at the end of this Section for the Drainage Review Flow Chart for the proposed building and Figure 4 for the Drainage Review Flow Chart for the proposed addition. Although independently each project is subject to a full drainage review, at the request of the City of Renton, the projects have been analyzed and will be reviewed as a combined project. Below is a description of each core requirement and how the project proposes to satisfy each requirement. 2.1.1 Core Requirement #1: Discharge at the Natural Location This requirement will be met by discharging stormwater to existing private stormwater networks, which ultimately discharge into Black River. 2.1.2 Core Requirement #2: Off-site Analysis The Off-Site Analysis included in Section 3.0 of this TIR will satisfy this Core Requirement. 2.1.3 Core Requirement #3: Flow Control Please see Section 4.0 for a discussion of flow control for the projects. The projects propose work within the Peak Rate Flow Control Standards (Existing Site Conditions) Area. The project must match the developed peak discharge rates to the existing site conditions peak discharge rates for the 2-, 10-, and 100-year return periods. Existing flow volumes from the proposed building will be matched through the use of a storage vault and variable speed pump station. Flows from the new construction will flow through the existing stormwater system that exits through the southwestern corner of the existing dealership parking lot. Runoff from the shared accessway will be split between the existing Buick-GMC wetvault and the new Cadillac stormwater system. The area flowing to the existing wetvault will be decreased due to modifications made on the south side of the new Cadillac dealership and will not receive a standalone flow control structure. The proposed addition will not receive a flow control structure. Stormwater runoff from the addition will not join the runoff from the new construction, but will maintain its current outfall to the west of the site. Stormwater from the frontage improvements, new building and new addition converge within ¼ mile of the site, downstream. As such, they are all considered to be part of the same Threshold Discharge Area (TDA), and are all subject to flow control. To mitigate the amount of storage required throughout the combined site, flow from the new building will be attenuated such that the overall outflow from the site will match the 2-, 10-, and 100-year return period rainfall events for the combined site. Flows will be attenuated through the use of a variable-flow pump system so that the overall site outflow matches the existing conditions. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 11 2.1.4 Core Requirement #4: Conveyance System Please see Section 5.0 of this TIR for the conveyance system analysis and design. The new building proposes to create a new stormwater system that will service stormwater that falls on-site, directing it to the existing stormwater system that services the existing dealership. The proposed addition will be connected to a private stormwater system to the west of the site, per existing conditions. Stormwater from upstream that will be flowing through the site will bypass storage and treatment before discharging into the existing downstream system in conjunction with stormwater treated on-site. A spill control tee section will be placed within CB08 and CB51 to handle spills on the new construction and new addition sites, respectively. 2.1.5 Core Requirement #5: Erosion and Sediment Control A temporary Erosion and Sediment Control Plan (TESC) will be prepared and included in the construction plan set. Additionally, a CSWPPP under a separate cover, will be provided to satisfy this requirement. 2.1.6 Core Requirement #6: Maintenance and Operations Please see Section 10.0 of this TIR for the Operations and Maintenance Manual, prepared to satisfy this Core Requirement. Brotherton Cadillac will be responsible for maintenance and operation of the proposed on-site stormwater facilities upon completion. The City of Renton will continue to be responsible for operation and maintenance of stormwater systems in the right-of-way. 2.1.7 Core Requirement #7: Financial Guarantees and Liability We anticipate that Brotherton Cadillac will be required to provide a Construction Bond to the City of Renton prior to issuance of the permit. The contractor/owner will be responsible for all erosion and maintenance liabilities during construction. 2.1.8 Core Requirement #8: Water Quality Please see Section 4.0 for a discussion of water quality for the project. Water quality treatment will be provided by Oldcastle BioPod Biofilters for both the proposed building and addition. Each BioPod will be sized and detailed according to the demands of the stormwater they are treating. The GULD for the BioPod is attached in Appendix A.9. Basic treatment will also be provided to the new building by a CONTECH CDS hydrodynamic separator. The GULD for the CDS is also attached in Appendix A.9. The portion of stormwater from the shared access that is not being treated by the Cadillac stormwater system will continue to be treated by the existing wetvault. 2.1.9 Core Requirement #9: On-site BMPs Target surfaces subject to Core Requirement #9 On-site BMPs include replaced impervious surfaces, already mitigated with an approved on-site BMP. This site qualifies for the Large Lot BMP Requirements per 1.2.9.2.2 of the City of Renton SWDM, since it is larger than 22,000 square feet. These requirements state that all proposed pervious surfaces must implement the soil amendment BMP and roof downspout connections must be perforated pipe connections. The soil amendment BMP will be implemented for every pervious service affected by construction. The downspout BMP does not apply to the proposed project as infiltration is not recommended on this site, per the geotechnical report in Section 6.0. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 12 In addition, these requirements require the consideration of the following BMPs: full dispersion, full infiltration, limited infiltration, bioretention, permeable pavement, basic dispersion, reduced impervious surface credit, native growth retention credit, tree retention credit. None of the listed BMPs are feasible for implementation on the project site, and will therefore not be implemented. The remainder of this section contains a discussion of infeasibility for each BMP. Full Dispersion – The application of this BMP depends on the sheet flow of runoff through an area of native vegetation. The project site does not contain any native vegetation area (e.g., forested) in the existing or proposed condition. Therefore, full dispersion is infeasible for this project. Full Infiltration – Per Section C.2.2.2 of the Manual, full infiltration requires that “Existing soils must be coarse sands or cobbles or medium sands and cannot be comprised of fill materials where the infiltration device will be located.” Site soils meet this requirement, except for the top layer of soil. However, the groundwater level renders infiltration on-site infeasible, as infiltration would have to occur in a silt material. These conditions are described in the Geotechnical Engineering Report prepared by Migizi Group, Inc. (dated July 8, 2021) for the proposed project. This report shows test pit logs with four distinct soil horizons, none of which provide viable infiltration due to either the groundwater level or material. The Geotechnical Engineer does not find that site soils will support Full or Limited infiltration (see section 3.4 Infiltration Conditions of the Migizi report). Therefore, full infiltration is infeasible for this project. Limited Infiltration – The infeasibility criteria for limited infiltration are the same as those for full infiltration except that appropriate soils may be fine sands, loamy sands, sandy loams, or loams. Note that Section C.2.3.2 of the Manual states “Silt and clay loams, and cemented till (hardpan) are not suitable for limited infiltration systems.” Site soils meet this requirement, except for the top layer of soil. However, the groundwater level renders infiltration on-site infeasible, as infiltration would have to occur in a silt material. The Geotechnical Engineer does not find that site soils will support Full or Limited infiltration (see section 3.4 Infiltration Conditions of the Migizi report). Therefore, limited infiltration is infeasible for this project. Bioretention – This project is underlain by soil that makes infiltration impractical, as such a bioretention facility is infeasible. Permeable Pavement – The soil under a permeable pavement section must provide adequate treatment for groundwater protection. The underlying soils should also infiltrate for this surfacing to be durable and effective. The requirements for adequate treatment are a minimum organic content of 1.0% and a minimum cation exchange capacity of 8 milliequivalents per 100 grams. The uppermost soil layer on the project site is made up of fill material and does not meet these requirements. Again, the depth to groundwater renders BMPs that rely on infiltration ineffective. Permeable Pavement is infeasible for this project. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 13 Basic Dispersion – The implementation of basic dispersion limits the area of impervious surface that can run off to a dispersion structure to 700 square feet per structure. The proposed construction will be adding over 16,500 square feet, which would require 24 separate flow dispersion structures. It is also required for the dispersed stormwater to flow over a vegetated surface, but there are no existing or proposed vegetated surfaces near the proposed development. Such a flowpath cannot be provided on the project site without a drastic reduction in the number of parking stalls and vehicle paths. We see basic dispersion as infeasible to the project. Reduced Impervious Surface Credit – This BMP presents four possible methods of impervious surface reduction: restricted footprint, wheel strip driveways, minimum disturbance foundation, and open grid decking over pervious surface. The restricted footprint method requires less than 4,000 square feet of impervious area, which is not feasible for the proposed use of the site as an automotive dealership. A wheel strip driveway is not applicable for a commercial parking lot. A minimum disturbance foundation is not feasible for an automotive workshop. Open grid decking over a pervious surface is also not applicable to a parking lot. The reduced impervious surface credit is infeasible for this project. Native Growth Retention Credit – The existing condition of the site does not contain any native growth. Therefore, the native growth retention credit is infeasible for this project. Tree Retention Credit – The existing condition of the site contains approximately 28 trees that will all be removed by the current owner as a condition of the lease agreement. Therefore, the tree retention credit is infeasible for this project. 2.1.10 Special Requirement #1: Other Adopted Area-Specific Requirements N/A. The project site is not in a designated critical drainage area or in an area included in an adopted master drainage plan, basin plan, salmon conservation plan, stormwater compliance plan, flood hazard management plan, lake management plan, or shared facility drainage plan. 2.1.11 Special Requirement #2: Flood Hazard Area Delineation N/A. Per the FEMA floodplain map at the end of this Section, Figures 5 and 6, the project sites lie within Zone X which is defined as “areas determined to be outside 500-year floodplain” and therefore flood-related delineation on the project site is not required. 2.1.12 Special Requirement #3: Flood Protection Facilities N/A. This project does not propose to rely on an existing flood protection facility nor does it modify or construct a new flood protection facility. 2.1.13 Special Requirement #4: Source Control Brotherton shall implement Operational and Structural Source Control BMPs that includes the maintenance of stormwater drainage and treatment systems as described in the Operations and Maintenance Manual, included in Section 10.0 of this report. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 14 2.1.14 Special Requirement #5: Oil Control This project does not propose to develop a high-use site as defined by City of Renton SWDM; therefore, this Special Requirement is not applicable. 2.1.15 Special Requirement #6: Aquifer Protection Areas This project is not located within an Aquifer Protection Area per King County GIS. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 15 Figure 3 – Drainage Review Flow Chart – Proposed Building BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 16 Figure 4 – Drainage Review Flow Chart – Proposed Addition BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 17 Figure 5 – FEMA Map – Proposed Building BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 18 Figure 6 – FEMA Map – Proposed Addition BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 19 3.0 OFF-SITE ANALYSIS Per City of Renton SWDM Section 1.2.2, this project must provide an off-site analysis report that assesses potential off-site drainage and water quality impacts associated with the redevelopment of the project site. The level of analysis required depends on the specific site and downstream conditions. In accordance with Section 1.2.2.1, a Level 1 Downstream Analysis has been performed. 3.1 Define and Map the Study Area Based on the current topographic survey and our observations of the site, the site is mostly tributary to an existing, private conveyance system. Those portions of the site that do not discharge to the existing, private conveyance system are tributary to an existing City conveyance system. The project does not propose any significant improvements to the existing conveyance elements on-site. Downstream of the project discharge locations, according to City of Renton GIS, stormwater from the proposed building site is conveyed west, into, and through, the neighboring Brotherton Cadillac automotive dealership stormwater system. Stormwater from the site of the proposed addition flows west into, and through, the neighboring Good Chevrolet automotive dealership stormwater system before heading south. The conveyance from both sites continues southward until it reaches Interstate 405 (I405). Before intersecting I405, stormwater flows into a catch basin on the north side and is diverted to the west. The pipe daylights and discharges the stormwater to flow over the surface before being collected in another City stormwater conveyance pipe on the south side of the existing Good Chevrolet, INC Chevrolet dealer. Stormwater then flows in another enclosed system under Lind Ave. SW before again daylighting and being discharged to run along the north side of I405. Stormwater continues flowing over the surface north of I405 before sheet flowing onto SW 13th St and being collected in a City catch basin. The pipe network downstream of this catch basin ultimately discharges into Black River. A topographic site map is featured in Figures 7 and 8 of this Report. Figure 7 - Downstream Flow Path – Proposed Building BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 20 Figure 8 – Downstream Flow Path – Proposed Addition BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 21 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 22 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 23 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 24 Figure 9 – Topographic Survey BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 25 3.2 Resource Review A thorough review of the resources provided by the City of Renton Maps, as outlined on page 2-11 of the SWDM, has been completed for the study area. Research conducted on 1/17/2022 has shown that there are not any adopted basin plans available for the study area. According to the FEMA Map presented in Figures 5 and 6 of this report, the project sites lie within Zone X, which is defined as areas outside the 500-year floodplain. The sites are located within the Duwamish – Green River Watershed, the Black River Basin, and the Springbrook Creek Sub Basin. Based on the City of Renton GIS, the project area has not been defined as a sensitive area. To our knowledge, there have not been any reported road drainage problems associated with the roads surrounding the site. It was also found that the site does not have a migrating river study, a 303d listing, or an adopted stormwater compliance plan available. Please see Section 4.0 for a discussion of water quality for the project. A geotechnical report completed by Migizi Group can be found in Appendix A.6. 3.3 Field Inspection During field inspections, the system appeared to be working sufficiently with no obvious clogs or flooding. We do not anticipate any future problems with the proposed stormwater system. The proposed conveyance system has more catch basins: therefore each individual catch basin will have a smaller tributary area. Stormwater flows on the site of the proposed building are expected to increase due to an increase in impervious surface, and will be handled by a pump station and supplementary detention system to match existing discharge into the existing downstream system. The amount of area tributary to the existing conveyance system connected to the proposed addition will remain largely the same – there is not a substantive increase in stormwater runoff tributary to the existing conveyance system as a result of the proposed addition. Please see Section A.5 for the modeled areas in the predeveloped and mitigated scenarios for both sites. Since it has been determined that there are no anticipated stormwater problems associated with this project, Level 2 and Level 3 downstream analyses are not required. No problems were found related to constrictions, capacity deficiencies, flooding, scouring, overtopping hazards, sedimentation or erosion, aquatic organisms or their habitation. Land use associated with the study area includes commercial/residential land applications, such as several automotive dealerships and the residential lots to the east of the site. In addition, the study area includes utilities and roadways. Existing impervious surfaces located within the study area include commercial businesses, compacted gravel access, paved parking lots, paved driveways, and the paved public right-of-way. Based on existing site topography, stormwater runoff is captured within the City’s right-of-way where it is collected by a storm conveyance system and discharged to the Black River. 3.4 Drainage System Description and Problem Descriptions No drainage system problems were observed during the field inspection. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 26 3.5 Mitigation of Existing or Potential Problems The proposed project area does not have any existing or anticipated drainage problems as outlined in Section 1.2.2.1 of the City of Renton SWDM. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 27 4.0 FLOW CONTROL, LID, AND WATER QUALITY FACILITY ANALYSIS AND DESIGN 4.1 Existing Site Hydrology The site of the proposed building currently has four residences, two sheds, shared lawn surfacing, and a large parking area composed of both crushed rock surfacing and asphalt cement pavement. Stormwater that does not infiltrate into the lawn sheetflows off-site, primarily onto either SW 12th St or SW 13th St. Run-off can flow onto the nearby existing Brotherton Cadillac dealership, although the site is graded in such a way that this is unlikely. From SW 12th St or SW 13th St, stormwater flows into City stormwater conveyance facilities. The site of the proposed addition currently has an automotive dealership with paved parking/display space that drains to one of two existing stormwater facilities on-site. One is a catch basin that flows directly into the City stormwater system from the southwest area of the site, which then discharges into Good Chevrolet’s private system. The other is a regional network that begins to the east of the site and directs stormwater into a large detention structure under the western parking area on-site. Prior to construction of the structural addition, the project site surfacing consisted of asphalt pavement, roofing, and landscaped islands. The addition and nearby parking are tributary to the neighboring Good Chevrolet’s conveyance system located on the west side of Maple Ave SW. 4.2 Developed Site Hydrology The proposed building site will be comprised of primarily asphalt pavement surfacing and roof area. There will be landscaped islands around the perimeter of the site, with approximately 4,840 square feet of landscaping. Stormwater on-site will be collected and conveyed into an on- site storage facility after treatment. The project does not propose to alter the downstream flow path and will maintain discharge to the natural location. The proposed addition site will be comprised of similar surfaces to existing, though some asphalt paved area will be converted to roofed area. In the developed condition, approximately 4,420 square feet of area which was previously asphalt pavement will now be rooftop surfacing. The project does not propose to alter the downstream flow path and will maintain discharge to the natural location. 4.3 Performance Standards The sites are within a Peak Rate Flow Control Standards (Existing Site Conditions) Area, which requires matching the existing site conditions 2-, 10-, and 100- year peak flows. The predeveloped sites are comprised of asphalt pavement, rooftop surfacing, lawn, and crushed rock surfacing. The proposed building site conditions include a significantly higher quantity of impervious surface than the existing conditions. The proposed addition site conditions include approximately 240 square feet more of impervious surfaces than the existing conditions on- site. Frontage improvements for the addition will replace approximately 930 square feet of landscaping with impervious surfaces. In areas where conveyance features are required, they have been designed in accordance with Section 1.2.4 of the SWDM. The proposed private conveyance elements for the proposed BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 28 building include conveyance piping from the new asphalt surfacing to an Oldcastle BioPod Biofilter before it is detained. Stormwater from the new roof will be conveyed directly to the detention facility. Enhanced basic water quality treatment is required for stormwater that falls on, or runs off of, pollution-generating surfaces on-site such as the parking lot. The treatment will be provided by the BioPod. Downstream of the storage structure is a pump that is set to match the existing 2, 10, and 100-year flow conditions that is tributary to the existing downstream stormwater system. The proposed private conveyance elements for the proposed addition include conveyance piping from the new roof to a private Type 1 catch basin that is separate from the stormwater network on site. Conveyance piping connects this catch basin to another existing private Type 1 catch basin, which then connects to the neighboring Good Chevrolet’s stormwater system on the west side of Maple Ave SW. It is proposed to install a small Oldcastle BioPod Biofilter on- site for treatment. 4.4 Flow Control System Flow control is required for the whole project. The proposed addition and frontage improvements will receive no flow control to either mitigate storage required on-site, or due to the receiving stormwater system being off-site. Flow control for the new building will be provided by a variable flow lift station. The lift station will attenuate flows from the new building site to provide flow control for the whole site. 4.4.1 Flow Control Exemptions Check The proposed building site is not exempt from flow control. See Section 2.1.3 of this report for further discussion. The proposed addition site is exempt from flow control due to an increase of less than 0.15 cfs in the 100-year storm event. See Section 2.1.3 of this report for further discussion. 4.4.2 Flow Control Area The site falls within a Peak Rate Flow Control Standard – Match Existing Area, based on the Flow Control Application Map provided by the City of Renton (Figure 10 of this TIR). 4.4.3 Flow Control Area Requirements and Exceptions Peak Rate Flow Control Standard – Match Existing – Areas must match existing site conditions 2-,10-, and 100-year peak rate runoff for areas draining to constructed (man-made) or highly modified drainage systems so as to not create a downstream flooding problem. Per Section 1.2.3.1.A, Exception 1, of the SWDM, the target surfaces of the proposed building subject to the Peak Rate Flow Control Standard Areas facility requirements will generate more than a 0.15-cfs increase in the existing site conditions peak flows. Therefore, the proposed building project proposes a pump station and supplementary detention system to serve as a flow control facility. The proposed addition is not expected to generate a 0.15cfs or greater increase in the 100-year peak flow, therefore flow control is not required for that project. 4.4.4 Identify Applicable Flow Control BMPs per Core Requirement #9 Please see Section 2.1.9 of this report for an evaluation of Flow Control BMPs per Core Requirement #9. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 29 4.5 Water Quality As mentioned in Section 4.3, both projects propose to satisfy the enhanced water quality requirement by installing an Oldcastle BioPod Biofilter. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 30 Figure 10- City of Renton Flow Control Application Map BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 31 5.0 CONVEYANCE SYSTEM ANALYSIS AND DESIGN Proposed conveyance elements include conveyance piping, storage, and a pump station for the new building. 8” PVC piping will be used for the roof drains of the new building, and 6” PVC piping will be used for the roof drains of the addition. 12” CPEP piping will be used for stormwater conveyance throughout the site at a minimum angle of 0.5%. The two graphs below were created with the use of WWHM, using a 15-minute time step to determine the expected 25 year peak flow that would be experienced by the eastern and western BioPods on-site, servicing the addition and new building, respectively. The WWHM Models used the surfaces and areas flowing into the BioPods, therefore they do not include areas for frontage improvements, or similar non-tributary areas. Figure 11 - WWHM Stormfall for the Eastern BioPod BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 32 Figure 12 - WWHM Stormfall Tributary to Western BioPod Using Manning’s Equation: 𝑄= 1.49 𝑛𝐴𝑄2 3⁄𝑄1 2⁄ Where A = 0.785ft2 for a 12” pipe, n = 13 for PVC or CPP, and S = 0.5% to represent the shallowest designed slope, yields a flow, Q, of 2.526cfs. This is above the 25 year peak flow rate for either system. A 6” diameter pipe, with an area of 0.196ft2 yields a flow of 0.398cfs, which is high enough to convey the 100 year peak flow rate for the system servicing the addition. The lift station servicing the new building was designed with the use of Autodesk Storm and Sanitary Analysis (SSA) to match the 2, 10, and 100-year storms while minimizing required storage for the entire project site, including frontage improvements. SSA reports are included in Appendix A.8. Design of the lift station was attempted with WWHM, but it was determined that the dual-pump system cannot be properly modeled in WWHM. The mitigated condition for the full site is included with the WWHM model for the full site, but it should be ignored. The design of the proposed conveyance systems, including the lift station, is discussed in more detail in Appendix A.5. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 33 6.0 SPECIAL REPORTS AND STUDIES We are not aware of any site characteristics that are particularly sensitive to stormwater runoff. A geotechnical report by Migizi Group can be found in Appendix A.6 of this report. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 34 7.0 OTHER PERMITS We anticipate that a Right-of-Way Use permit, Land Use Master Application, Civil Construction Permit, Building Permit, NPDES permit, and an Environmental Review Permit (SEPA) will be required. A leachable materials covenant will be required for the constructed rooftops to qualify them as NPGIS (non-pollution generating impervious surface). Franchise permits will be required for each franchise affected by overhead utilities being undergrounded. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 35 8.0 CSWPPP ANALYSIS AND DESIGN The Construction Stormwater Pollution Prevention Plan reports is included under a separate cover. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 36 9.0 BOND QUANTITIES AND R/D FACILITY SUMMARIES 9.1 Bond Quantities See Appendix A.2 for a copy of the City of Renton bond report. 9.2 Facility Summaries These projects propose to implement a Contech CDS hydrodynamic separator, Oldcastle BioPod Biofilters, Oldcastle StormCapture water detention, stormwater pump station, collection catch basins, and conveyance piping. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 37 10.0 OPERATIONS AND MAINTENANCE MANUAL 10.1 Purpose The purpose of this manual is to provide guidelines for maintaining the storm drainage system as a part of the construction for the new Brotherton Cadillac building and new Brotherton Buick-GMC building addition. The neighboring site addresses are 201 SW 12th Street and 215 SW 12th Street, Renton, WA 98057. Storm utility improvements that have been proposed as a part of the projects include: o Contech CDS hydrodynamic separator o Oldcastle BioPod Biofilter o Oldcastle StormCapture o Storm Drainage Piping o Catch Basins o Pump Station Each portion of the system has to be maintained in good working condition for the system to function properly. Operations and Maintenance of the private drainage systems will be the responsibility of the Owner, Brotherton. Brad Brotherton is the contact person at Brotherton. His contact information is: Brad Brotherton Brotherton Cadillac 215 Southwest 12th Street Renton, WA 98057 Phone: (425) 336-1089 The City of Renton will continue to be responsible for the Operation and Maintenance of public improvements. 10.2 Permanent Facilities Description Conveyance piping will convey stormwater from the new rooftop and paved surfaces to the existing stormwater facilities on-site. The project does not propose to alter downstream flow paths and will maintain ultimate discharge to the Black River. For the proposed building, a Contech CDS hydrodynamic separator and Oldcastle BioPod Biofilter will provide water quality treatment. Oldcastle StormCapture will store stormwater so it can be discharged at a controlled rate by the proposed pump station. The proposed addition will be treated by n Oldcastle BioPod Biofilter. 10.3 Discussion of Maintenance Any buildup of sediment, debris, vegetation, or trash that impedes the catch basins will reduce the storm system capacity. As a result, care must be taken to keep all inlets clear of debris. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 38 The applicable maintenance checklists and excerpts from the 2017 SWDM have been included with the Operations and Maintenance Manual for review during routine maintenance inspections. 10.4 Maintenance Frequency Following construction of the project, the storm drainage system shall be inspected and maintained according to their respective maintenance checklists included at the end of this manual. Facilities will be inspected annually, or after every significant storm event where the precipitation is greater than or equal to one inch in 24 hours When deficiencies are noted, the problems are to be corrected as soon as possible. Any spill of hazardous material (e.g. fuel, lubricant, herbicide, etc.) shall be cleaned up immediately and shall be reported to the Division of Emergency Management (1-800-523-5044). Contaminated material will be disposed of properly. Any questions about the existence of a problem should be directed to a Professional Engineer. 10.5 Annual Cost Estimate Annual maintenance costs for the proposed stormwater conveyance system on-site for the proposed building is expected to increase the costs of maintaining the private stormwater system by $1 for every linear foot of new piping, $500 for each CDS, $500 for every BioPod, $500 per pump station, and $300 for each StormCapture unit. Approximately 1850 linear feet of proposed pipe, one CDS, one BioPod, one pump station, and 5 StormCapture units will have an annual cost of maintenance of $4,850 for the proposed building. Annual maintenance costs for the proposed stormwater conveyance system on-site for the proposed addition is expected to increase the costs of maintaining the private stormwater system by $1 for every linear foot of new piping and $500 for every BioPod. Approximately 200 linear feet of proposed pipe and one BioPod will increase the cost of maintenance by $700. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 39 Cover Sheet for Inspection Forms Name of Inspector: _____________________________________________________________ Date of Inspection: _____________________________________________________________ Number of Sheets Attached: _____________________________________________________________ Inspector’s Signature: _____________________________________________________________ BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 40 Maintenance Log Action Taken Name Date How Procedure Was Performed Problems Encountered Additional Actions Recommended BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 41 A.1 TIR Worksheet BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 42 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 43 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 44 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 45 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 46 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 47 Figure 13 – TIR Worksheet BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 48 A.2 Bond Quantity Worksheet The Bond Quantity Worksheet is included under a separate cover. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 49 A.3 Existing and Proposed Surface Coverage Exhibits BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 50 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 51 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 52 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 53 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 54 A.4 Site Historical Aerial Photography BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 55 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 56 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 57 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 58 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 59 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 60 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 61 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 62 A.5 Stormwater Engineering Calculations Proposed Building: Conditions This project is in a location subject to meeting the Peak Rate Flow Control Standard, as described in Section 4.4. Therefore, we have prepared the following calculations to determine if flow control will be required for this project. As previously mentioned, the site is predominantly currently covered by lawn and several small structures. The site presently discharges offsite to the west. There is presently no treatment or flow control in this system. Flow control will be required to be installed in this system to match the existing discharge rate for the 2-, 10-, and 100-year storm peak flow rates. Predeveloped Conditions: Based on aerial photographs, included in Section A.4, the site had previously been, and is currently, a residential location. The eastern residences appear to have been replaced with parking between May of 2013 and May of 2018. Areas of the replaced residential space used for stormwater design were acquired from aerial photographs taken in May of 2010 as they are clear enough to use for approximate surface areas. Spaces that appear to have remained largely unchanged had their areas gathered from survey data of the site. See the following excerpt from WWHM indicating the assumptions used in the “Predeveloped” Condition: Figure 14 - Predeveloped conditions for the Cadillac site used for Water Quality BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 63 Mitigated Conditions: The mitigated site coverage is comprised of asphalt pavement parking and the rooftop of the proposed structure with sidewalks and landscaping along the perimeter of the site and proposed automotive dealership. See the following excerpt from WWHM indicating the assumptions used in the “Mitigated” Condition: Figure 15 - Developed conditions for the Cadillac site used for Water Quality Flow Frequency Results: The flow frequency table included on the following page indicates that the peak stormwater runoff from the developed site will increase by more than 0.15cfs for the 100-year storm condition. As the flow is expected to change by more than 0.15cfs, and more than 5,000 square feet of new and replaced impervious surface are proposed, a flow control structure will be necessary. It is proposed to use a pump station for flow control, and to maintain connection with the existing downstream facilities. Excess flow will be detained in connected Contech clamshell storage vaults. Design of the flow control structure is explained in more detail in the Combined Site section. Water Quality More than 5,000 square feet of impervious surface is being installed or replaced as a result of this project: therefore water quality treatment is required. Water quality treatment flows calculated by WWHM are shown below. Surfaces tributary to the BioPod installed on the BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 64 Cadillac site were used to determine sizing. These surfaces include the parking lot and installed asphalt, but not frontage improvements. The proposed single-ply TPO or PVC membrane fabric rooftop was not included in the water quality calculations as it is considered to not be a pollution-generating surface and will bypass the treatment structure. It was, however, included in the calculations for detention requirements. Treatment flows did not change with, or without, the inclusion of the roof surface. Using the off-line correction factor located in Table 6.2.1.A of The Manual, with a 2-year storm rainfall intensity of 2 inches from the isopluvial maps located in Section 3.2.1 of The Manual, the correction factor is 3.5312. Using this correction factor and multiplying it by the calculated off-line water quality flow, 0.0974 cfs, the design water quality treatment flow for an off-line treatment structure for the new construction is 0.344 cfs. An 8x16 Oldcastle BioPod Biofilter has been selected as an off-line treatment structure, as it has an enhanced treatment capacity of 0.384 cfs. Figure 16 – WWHM 2012 Flow Frequency calculations for the Cadillac site BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 65 Figure 17 - WWHM 2012 Water Quality calculations for the Cadillac site Proposed Addition: Conditions This project is in a location subject to meeting the Peak Rate Flow Control Standard, as described in Section 4.4. Therefore, we have prepared the following calculations to determine if flow control will be required for this project. As previously mentioned, the site is predominantly already covered by asphalt parking areas and a structure. The asphalt being replaced presently discharges offsite to the west, separate from the existing wet vault. There is presently no treatment or flow control in this system. No flow control would normally be required, or proposed, to be installed in this system, as the peak flow produced by the 100-year storm does not increase by more than 0.15 cfs if the existing site conditions are assumed to be lawn. As this site is part of a larger TDA that is subject to flow control, it will receive flow control. However, the flow control will be provided by attenuation of the stormwater from the new building on the Cadillac site to match the existing storm flows. Predeveloped Conditions: Based on aerial photographs, included in Section A.4, the site had previously been a residential location before the construction of the existing Brotherton Cadillac automotive dealership. Any reference we have access to showing this residential development are too blurry to acquire usable areas for stormwater calculations. As such, it will be assumed that the existing site condition is flat lawn covering, as that is the most restrictive from a stormwater design perspective that would be possible. See the following excerpt from WWHM indicating the assumptions used in the “Predeveloped” Condition: BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 66 Figure 18 - Predeveloped conditions for the Buick-GMC site used for Water Quality Mitigated Conditions: The mitigated site coverage is comprised of primarily asphalt pavement parking and the rooftop of the proposed structure. See the following excerpt from WWHM indicating the assumptions used in the “Mitigated” Condition: Figure 19 - Developed conditions for the Buick-GMC site used for Water Quality Flow Frequency Results: BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 67 The flow frequency table included on the following page indicates that the peak stormwater runoff from the developed site will increase by less than 0.15cfs for the 100-year storm condition. As the flow is expected to change by less than 0.15cfs, a stand-alone flow control structure will not be provided for the addition. Instead, flow control for the entirety of the project site will be handled by a pump station located in the parking lot of the new building. Water Quality More than 5,000 square feet of impervious surface is being replaced during this project. While the net pollution-generating surface is decreasing, water quality treatment is required. Water quality treatment flows calculated by WWHM are shown below. Surfaces included for treatment sizing of the Western BioPod are the replaced asphalt and the rooftop of the addition. The proposed rooftop was included in the water quality calculations, even though it is considered to not be a pollution-generating surface, as it will not bypass the treatment structure. Frontage improvements, on- and off-site, were not included in treatment sizing calculations. Using the off-line correction factor located in Table 6.2.1.A of The Manual, with a 2-year storm rainfall intensity of 2 inches from the isopluvial maps located in Section 3.2.1 of The Manual, the correction factor is 3.5312. Using this correction factor and multiplying it by the calculated off-line water quality flow, 0.0198cfs, the design water quality treatment flow for an off-line treatment structure for the new construction is 0.0699 cfs. An 4x8 Oldcastle BioPod Biofilter has been selected as an off-line treatment structure, as it has a treatment capacity of 0.096 cfs. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 68 Figure 20 - WWHM 2012 Flow Frequency calculations for the Buick-GMC site Figure 21 - WWHM 2012 Water Quality calculations for the Buick-GMC site BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 69 Combined Site Flow Control As stated in Section 2.1.3 of this report, the site is subject to Peak Rate Flow Control Standard (Existing Site Conditions) and must therefore match the developed peak discharge rates of the existing condition’s 2-, 10-, and 100-year return period storms. Western Washington Hydrology Model (WWHM) was used to determine the peak storm flows for the site, based on existing conditions. Existing conditions are described in Section 1.2 of this report, as well as A.3. The full project boundary, including frontage improvements, was used to determine the existing and proposed surface conditions used for flow control calculations. These surface conditions can be seen in Appendix A.3, and Tables 1 and 2. Additionally, the area for the existing portion of the shared access that is not being affected by this project was included in both the WWHM and SSA models. This area was included to ensure all runoff flowing through a control structure was being accounted for. It is not included in Tables 1 and 2, or in Appendix A.3. however, it can be seen in the drainage basin exhibits at the end of A.5. The WWHM process is described in A.5, and the results are included as A.7. These flows were used as design flows for the pump station. The target flows for the whole site are also highlighted in Figure 22. Figure 22 - WWHM 2012 Flow Frequency Calculations for the combined project area – Bypass and Pumped BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 70 A style of variable-speed pump was originally chosen that could handle flow control requirements for the Cadillac site, and only the Cadillac site. The original plan was to use two pumps with a series of floats that would toggle minimum and maximum flow states for the two pumps. One pump (lead pump) was to start at a minimum flow state for the 2-year storm, then the second (lag pump) would activate at a minimum flow state for the 10-year storm, and both would engage a maximum flow state for the 100-year storm. However, after consultation with the City of Renton, it was determined that the pump would need to serve as flow control for the whole site. As such, the timing and operation of the pumps has been modified. The current design has one pump engage a minimum flow state for the 2-year storm and then increase to a maximum flow state for the 10-year storm. The lag pump will then engage in a minimum flow state for the 100-year storm. From the results of the SSA model, discussed further in this appendix, if the lag pump were to engage in a maximum flow state to assist with the 100-year storm, then the downstream system would experience more flow than the existing conditions. Using the lag pump in a minimum flow state in this manner also allows for the lag pump to be engaged in a maximum flow state should it be required. Pumps will be engaged in minimum or maximum flow states by controlling the current they receive through a series of float switches. Once activated, a pump will remain in the last state activated until the water level in the lift station is low enough to trigger the pump off float switch. The designation of lead and lag pump will alternate to mitigate wear and tear on the pumps. Included in the pump station structure are a series of float switches that will activate the pumps at their required flow states, and low and high water level alarm floats. The low water level alarm will alert the owner that the pump is no longer submerged, which could cause damage to the pump. The high water level alarm will alert the owner that the water level is becoming close to overtopping the structure. The elevations of each of the previously mentioned float switches is provided on sheet C3.10C of the civil construction drawing set. To prevent overtopping, in the case of a pump failure, a 12” pipe will be installed near the top of the structure that will connect to the nearby bypass for surface water from surfaces to the east to serve as an emergency overflow. To determine the required pump characteristics, a system-demand curve (SDC) was generated using a combination of the static head and frictional losses in the pump system. A system- demand curve represents the amount of total dynamic head (TDH) that will be generated at certain flows through the system. The static head is the difference between the standing water level of the pump station and the invert elevation of the outlet. Frictional losses were computed using the Hazen-Williams friction coefficient: ℎ𝑓=10.44 ∗(𝐿)∗((𝑄)1.85 (𝐶)1.85 ∗(𝑑)4.8655) Where: • hf is the head for the frictional loss in a pipe, in feet • L is the length of the pipe, in feet • Q is the flow through the pipe, in gallons per minute • C is the Hazen-Williams roughness coefficient • d is the diameter of the pipe, in inches BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 71 Frictional loss was calculated for every different pipe diameter and material used in the force main. Both pipes used in this force main are PVC, one is 4 inches and the other is 6 inches. PVC has a Hazen-Williams roughness coefficient of 150. To account for minor losses of pipe fittings (e.g., bends, enlargements, valves, etc.) that can greatly affect the performance of a pump, a nomograph was used to convert minor losses into an equivalent length of pipe for each pipe. The nomograph, Figure 9.2 of the Handbook of PVC Pipe, 5th Edition, is included as Figure 24. The equivalent length of the 4 inch diameter pipe used for calculations was 105.5 feet, and the 6 inch pipe’s equivalent length was 46.1. Frictional losses for each pipe are added together, with the static head to determine the TDH for a given flow. To create an SDC, TDH is determined for several flows and graphed. This project started with a flow of 0 gpm and calculated the TDH for every flow up to 300 gpm in 50 gpm increments. TDH was calculated for the 2-, 10-, and 100-year design flows using the same method as the SDC. The design flows were gathered from WWHM and converted into gallons per minute. On the graph, they are represented by enlarged, hollow circles to highlight their location relative to the operational envelope of the pumps. After the original design flows had been calculated and graphed, the envelopes of several variable-flow pumps were compared to the design flows. When comparing the pump curves of various multi-phase pumps to original project requirements, the Flygt NP 3085 SH was deemed to be the most appropriate. The lower and upper limits of the pump curve for the NP 3085 SH were graphed against the system demand curve in Figure 23. Technical cut sheets for the selected pump can be found in A.10. The four pump curves shown are the minimum output of a single pump operating, the minimum output of both pumps operating, a mix of one pump operating at minimum and one at maximum, and both pumps operating at maximum output. These curves generate an “operational envelope,” that bounds the potential flows the pump system can produce. Each of the design flows appear within the operational envelope, meaning this pump configuration can handle the original design flows for the Cadillac site. This model of multi-phase pump was used when the design shifted to include flow control for the entire project site and was found through SSA modeling to still be sufficient. Float switch elevations were determined through the use of an SSA model of the proposed stormwater system and an iterative process of adjusting the pump activation depth. SSA has four options for pump curves, one that moderates flow by available volume, one that moderates flow by the head difference between the structure inlet and outlet, and two that determine the flow by the depth of water in the structure. One of the two options that determines flow based on the depth of water in the structure uses a variable-flow pump curve while the other uses a step function to determine set flows at set depths. The option that utilizes the difference in head between the inlet and outlet was used to determine the float elevations as it most closely resembles the proposed conditions. Two pump curves were created in SSA to represent the proposed conditions. One curve was created to mimic the minimum output pump curve, included as Figure 25. The other pump curve, included as Figure 26, is the difference between the minimum and maximum output for a single pump. With these two pump curves set up in this fashion, it is possible to model a pump BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 72 running at minimum output until water reaches a depth that would activate the maximum output mode. At the depth that the pump would switch to maximum output, the second pump curve is activated so the two curves are being used concurrently, representing one pump running at maximum output. This is shown on Figures 30 and 32, where a new pump flow curve appears on the graph and does not match the one that is already there. On Figure 32, the lag pump can be seen activating at minimum output, after the maximum output curve for the lead pump has been activated, and matching the minimum output curve of the lead pump Activation depths for the pumps and their flow states were designed iteratively with the use of SSA. The objective for each activation depth was to activate a pump flow state that would match the required storm design flow without flooding the system, and to prevent a lower- severity storm from activating a higher-severity storm (e.g. a 2-year storm triggering the 10- year storm design flow). Beginning with the 2-year storm event, activation depths were determined that would allow the overall system outflow to match the design 2-year flow from WWHM through the use of the lead pump, while it was set to minimum output. The same process was taken for the 10-year storm event, but the depth at which the lead pump switches to maximum output instead of a pump activating at minimum output. The lag pump’s minimum output was used to determine if there was a viable activation depth to assist with the 100-year activation depth that did not require the lag pump to switch into maximum output. It was found through iterative design that the lag pump did not need to engage in maximum output to assist with the 100-year storm flow, which will mitigate wear put on the lag pump. If the activation depths were too low, the pump would cause too much water to flow downstream during the peak of the storm and if they were too high, it brought the system to flooding or requiring an additional StormCapture storage unit. During the design process, activation depths were compared to the depth of the selected StormCapture stormwater storage system. Increasing and decreasing the amount of storage in the system greatly affected each activation depth. Each StormCapture unit has an internal functional depth and width of seven feet, with an internal functional length of 15 feet. Each unit has a floor area of 105 square feet and a total volume of 735 cubic feet. Storage curves were created to represent available storage volumes offered by different amounts of StormCapture units, as necessary. Each storage curve also included the volume offered by access manholes and service vents, but this space was treated as “emergency-only storage.” The storage curves are shown as Figure 27. If the WWHM Water Quality storage volumes for the Cadillac and Buick-GMC sites were combined into a single storage volume, it would be 0.1699 acre-feet, or 7,400 cubic feet. This volume would require the installation of ten StormCapture units. While the site has space for that many StormCapture units, it was determined through iterative SSA design that only five units were needed in conjunction with the staged pump station. Figures 28-33 are screenshots from SSA showing the depth of water in the pump station and the storage vault, the flow through the pump over a 24-hour period, and the total outfall for the entire expanded project area. The expanded project area includes the frontage improvements for the new construction and existing building, surfaces directly affected by the BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 73 project, as well as the portion of the southeast existing Buick-GMC parking lot that is unaffected by the project but will still flow through the . These graphs show that the structures will not overflow for the 2-, 10-, and 100-year return storm events and that the pump will provide the required water flows. Peak flow for the 2-year storm of the developed condition from SSA is 0.40cfs, which is approximately 0.01cfs lower than the WWHM-calculated flow of 0.41cfs. SSA modeling shows the 10-year developed condition to have a flow of 0.63cfs, which is approximately 0.01cfs lower than the WWHM- calculated flow of 0.64cfs. Similarly, the peak flow of the developed 100-year storm is 0.94cfs, which is approximately 0.02cfs less than the WHM-calculated flow of 0.96cfs. These are very small differences and should not cause problems downstream of the lift station. Type IA 24-hour storms compiled from historical rainfall data for King County, Washington were used in the SSA model to calculate surface water for each basin for each design storm event. Drainage basins are illustrated in the exhibits included at the end of A.5. Table 3. Pump Total Dynamic Head vs Flow (gpm) Pump Curve TDH (FT) Single Pump, Min Flow Single Pump, Max Flow Both Pumps, One Max- One Min Both Pumps, Max Flow 5 138 192 330 384 10 94 164 258 328 15 42 126 168 252 20 0 85 85 170 25 0 40 40 80 30 0 6 6 12 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 74 Figure 23 - Pump Operation Envelope 0 5 10 15 20 25 30 35 0.00 50.00 100.00 150.00 200.00 250.00 300.00 350.00 400.00 450.00TDH (FT)Flow (GPM) Single Pump, Minimum Flow Single Pump, Maximum Flow 2-year Storm 10-year Storm 100-year Storm Both Pumps, One Max-One Min System Demand Curve Both Pumps, One Max-One Min BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 75 Figure 24 - Minor Loss Nomograph BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 76 Figure 25 – Minimum Pump Curve Head (ft) vs Flow (cfs) BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 77 Figure 26 - Difference between upper and lower pump curve head (ft) vs flow (cfs) BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 78 Figure 27 - Storage curve for 5 StormCapture units BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 79 Figure 28 - 2-year Total System Inflow, Pump Flow, and System Outflow vs Time Lead Pump Low-Flow Peak Flow: 0.25cfs Total Combined (Pumped and Bypass) Site Peak Outflow: 0.40cfs Total Combined (Pumped and Bypass) Site Peak Inflow: 0.75cfs BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 80 Figure 29 – 2-year Water Depth and Storage Volume for StormCapture units and lift station StormCapture Peak Volume: 2100.32 ft3 Lift Station Peak Volume: 121.42 ft3 StormCapture Peak Depth: 4.00 ft Lift Station Peak Depth: 4.15 ft BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 81 Figure 30 - 10-year Storage Depth, Pump Flow, and System Outflow vs Time Lead Pump Low-Flow Peak Flow: 0.28cfs Total Combined (Pumped and Bypass) Site Peak Outflow: 0.63cfs Lead Pump High-Flow Peak Additional Flow: 0.17cfs Total Combined (Pumped and Bypass) Site Peak Inflow: 1.13cfs BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 82 Figure 31 - 10-year Water Depth and Storage Volume for StormCapture units and lift station StormCapture Peak Volume: 2856.04 ft3 Lift Station Peak Volume: 163.46 ft3 StormCapture Peak Depth: 5.54 ft Lift Station Peak Depth: 5.58 ft BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 83 Figure 32 - 100-year Storage Depth, Pump Flow, and System Outflow vs Time Lead Pump Low-Flow Peak Flow: 0.27cfs Total Combined (Pumped and Bypass) Site Peak Outflow: 0.94cfs Lag Pump Low-Flow Peak Flow: 0.22cfs Lead Pump High-Flow Peak Additional Flow: 0.18cfs Total Combined (Pumped and Bypass) Site Peak Inflow: 1.63cfs BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 84 Figure 33 – 100-year Water Depth and Storage Volume for StormCapture units and lift station StormCapture Peak Volume: 3468.52 ft3 Lift Station Peak Volume: 197.40 ft3 StormCapture Peak Depth: 6.61 ft Lift Station Peak Depth: 6.74 ft BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 85 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 86 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 87 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 88 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 89 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 90 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 91 A.6 Geotechnical Engineering Report The Geotechnical Report, prepared by Migizi Group, Inc, dated July 8, 2021, is included under a separate cover. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 92 A.7 WWHM Reports BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 93 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 19480 - Brotherton Buick-GMC - Treatment Site Name: Brotherton Buick-GMC Site Address: 215 SW 12th St City : Renton, WA Report Date: 3/15/2023 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 (adjusted) Precip Scale: 0.00 Version Date: 2021/08/18 Version : 4.2.18 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Existing Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .22 Pervious Total 0.22 Impervious Land Use acre Impervious Total 0 Basin Total 0.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Proposed Bypass: No GroundWater: No BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 94 Pervious Land Use acre C, Lawn, Flat .004 Pervious Total 0.004 Impervious Land Use acre ROOF TOPS FLAT 0.101 PARKING FLAT 0.115 Impervious Total 0.216 Basin Total 0.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.22 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.004 Total Impervious Area:0.216 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.017328 5 year 0.03143 10 year 0.042905 25 year 0.059793 50 year 0.074091 100 year 0.08985 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.082611 5 year 0.104431 10 year 0.119265 25 year 0.138517 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 95 50 year 0.153257 100 year 0.168361 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.036 0.107 1950 0.041 0.115 1951 0.019 0.067 1952 0.008 0.059 1953 0.006 0.064 1954 0.012 0.067 1955 0.013 0.076 1956 0.017 0.075 1957 0.021 0.085 1958 0.012 0.069 1959 0.009 0.070 1960 0.021 0.069 1961 0.015 0.073 1962 0.005 0.063 1963 0.015 0.070 1964 0.016 0.069 1965 0.024 0.088 1966 0.009 0.059 1967 0.041 0.101 1968 0.019 0.115 1969 0.021 0.080 1970 0.014 0.077 1971 0.022 0.092 1972 0.035 0.095 1973 0.007 0.057 1974 0.020 0.084 1975 0.023 0.096 1976 0.015 0.065 1977 0.013 0.070 1978 0.014 0.086 1979 0.005 0.117 1980 0.044 0.106 1981 0.013 0.086 1982 0.039 0.122 1983 0.019 0.099 1984 0.010 0.062 1985 0.014 0.086 1986 0.018 0.075 1987 0.018 0.115 1988 0.006 0.070 1989 0.005 0.087 1990 0.083 0.148 1991 0.052 0.118 1992 0.013 0.062 1993 0.008 0.054 1994 0.005 0.058 1995 0.012 0.076 1996 0.035 0.082 1997 0.021 0.079 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 96 1998 0.016 0.080 1999 0.060 0.164 2000 0.016 0.082 2001 0.004 0.090 2002 0.033 0.105 2003 0.026 0.082 2004 0.041 0.154 2005 0.018 0.070 2006 0.019 0.062 2007 0.077 0.144 2008 0.050 0.116 2009 0.026 0.106 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.0827 0.1643 2 0.0770 0.1537 3 0.0602 0.1483 4 0.0517 0.1437 5 0.0505 0.1219 6 0.0440 0.1182 7 0.0411 0.1173 8 0.0410 0.1161 9 0.0405 0.1154 10 0.0389 0.1150 11 0.0364 0.1147 12 0.0352 0.1072 13 0.0352 0.1065 14 0.0331 0.1060 15 0.0258 0.1049 16 0.0258 0.1009 17 0.0239 0.0989 18 0.0229 0.0962 19 0.0224 0.0951 20 0.0214 0.0918 21 0.0213 0.0895 22 0.0213 0.0877 23 0.0210 0.0871 24 0.0196 0.0863 25 0.0194 0.0861 26 0.0191 0.0857 27 0.0189 0.0851 28 0.0187 0.0838 29 0.0183 0.0817 30 0.0181 0.0817 31 0.0177 0.0815 32 0.0175 0.0801 33 0.0161 0.0799 34 0.0158 0.0792 35 0.0157 0.0770 36 0.0154 0.0765 37 0.0150 0.0761 38 0.0149 0.0749 39 0.0142 0.0745 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 97 40 0.0137 0.0727 41 0.0137 0.0704 42 0.0135 0.0702 43 0.0129 0.0700 44 0.0128 0.0698 45 0.0127 0.0697 46 0.0118 0.0688 47 0.0116 0.0688 48 0.0116 0.0685 49 0.0103 0.0672 50 0.0090 0.0670 51 0.0087 0.0649 52 0.0079 0.0641 53 0.0075 0.0632 54 0.0070 0.0625 55 0.0063 0.0621 56 0.0057 0.0619 57 0.0051 0.0593 58 0.0049 0.0585 59 0.0049 0.0581 60 0.0047 0.0572 61 0.0042 0.0535 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility FAILED Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.0087 3480 57194 1643 Fail 0.0093 2710 52167 1924 Fail 0.0100 2214 47890 2163 Fail 0.0106 1824 43868 2405 Fail 0.0113 1455 40296 2769 Fail 0.0120 1215 36960 3041 Fail 0.0126 977 33965 3476 Fail 0.0133 766 31206 4073 Fail 0.0140 598 28747 4807 Fail 0.0146 467 26501 5674 Fail 0.0153 385 24447 6349 Fail 0.0159 315 22544 7156 Fail 0.0166 250 20805 8322 Fail 0.0173 220 19248 8749 Fail 0.0179 180 17879 9932 Fail 0.0186 153 16578 10835 Fail 0.0192 135 15370 11385 Fail 0.0199 124 14262 11501 Fail 0.0206 116 13267 11437 Fail 0.0212 109 12386 11363 Fail 0.0219 99 11541 11657 Fail 0.0225 91 10712 11771 Fail 0.0232 86 9965 11587 Fail 0.0239 82 9306 11348 Fail 0.0245 78 8727 11188 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 98 0.0252 76 8164 10742 Fail 0.0258 71 7584 10681 Fail 0.0265 68 7069 10395 Fail 0.0272 66 6624 10036 Fail 0.0278 62 6175 9959 Fail 0.0285 61 5794 9498 Fail 0.0292 57 5450 9561 Fail 0.0298 53 5086 9596 Fail 0.0305 49 4765 9724 Fail 0.0311 48 4470 9312 Fail 0.0318 45 4194 9320 Fail 0.0325 43 3927 9132 Fail 0.0331 38 3681 9686 Fail 0.0338 37 3476 9394 Fail 0.0344 36 3290 9138 Fail 0.0351 35 3121 8917 Fail 0.0358 33 2937 8900 Fail 0.0364 30 2753 9176 Fail 0.0371 30 2592 8640 Fail 0.0377 28 2458 8778 Fail 0.0384 26 2338 8992 Fail 0.0391 24 2205 9187 Fail 0.0397 22 2074 9427 Fail 0.0404 22 1954 8881 Fail 0.0410 19 1838 9673 Fail 0.0417 18 1733 9627 Fail 0.0424 15 1645 10966 Fail 0.0430 15 1549 10326 Fail 0.0437 13 1448 11138 Fail 0.0444 11 1379 12536 Fail 0.0450 11 1303 11845 Fail 0.0457 10 1230 12300 Fail 0.0463 9 1172 13022 Fail 0.0470 9 1095 12166 Fail 0.0477 8 1035 12937 Fail 0.0483 8 984 12300 Fail 0.0490 8 938 11725 Fail 0.0496 7 885 12642 Fail 0.0503 7 854 12200 Fail 0.0510 6 817 13616 Fail 0.0516 6 775 12916 Fail 0.0523 5 740 14800 Fail 0.0529 5 709 14180 Fail 0.0536 5 669 13380 Fail 0.0543 5 631 12620 Fail 0.0549 5 606 12120 Fail 0.0556 5 586 11720 Fail 0.0562 5 558 11160 Fail 0.0569 4 540 13500 Fail 0.0576 4 513 12825 Fail 0.0582 4 489 12225 Fail 0.0589 3 460 15333 Fail 0.0596 3 439 14633 Fail 0.0602 3 423 14100 Fail 0.0609 2 409 20450 Fail 0.0615 2 389 19450 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 99 0.0622 2 375 18750 Fail 0.0629 2 359 17950 Fail 0.0635 2 344 17200 Fail 0.0642 2 327 16350 Fail 0.0648 2 319 15950 Fail 0.0655 2 307 15350 Fail 0.0662 2 293 14650 Fail 0.0668 2 278 13900 Fail 0.0675 2 269 13450 Fail 0.0681 2 261 13050 Fail 0.0688 2 249 12450 Fail 0.0695 2 239 11950 Fail 0.0701 2 228 11400 Fail 0.0708 2 220 11000 Fail 0.0714 2 211 10550 Fail 0.0721 2 204 10200 Fail 0.0728 2 196 9800 Fail 0.0734 2 184 9200 Fail 0.0741 2 180 9000 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: 0.0266 acre-feet On-line facility target flow: 0.035 cfs. Adjusted for 15 min: 0.035 cfs. Off-line facility target flow: 0.0198 cfs. Adjusted for 15 min: 0.0198 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 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 100 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. 2005-2023; All Rights Reserved. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 101 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 19480 - Brotherton Cadillac Treatment Site Name: Brotherton Cadillac Site Address: 209 SW 12th St City : Renton, WA Report Date: 3/15/2023 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2021/08/18 Version : 4.2.18 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Existing Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .667 Pervious Total 0.667 Impervious Land Use acre ROOF TOPS FLAT 0.179 SIDEWALKS FLAT 0.034 PARKING FLAT 0.298 Impervious Total 0.511 Basin Total 1.178 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : ProposedDevel BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 102 Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .109 Pervious Total 0.109 Impervious Land Use acre ROOF TOPS FLAT 0.374 SIDEWALKS FLAT 0.039 PARKING FLAT 0.656 Impervious Total 1.069 Basin Total 1.178 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Storm Capture 1 Storm Capture 1 ___________________________________________________________________ Name : Storm Capture 1 Facility Name: Storm Capture 1 Dimensions Depth: 7 ft. Length : 60 ft. Width : 7 ft. Discharge Structure Riser Height: 0 ft. Riser Diameter: 0 in. Orifice 1 Diameter: 8 in. Elevation: 0 ft. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ SCapture Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.009 0.000 0.000 0.000 0.0778 0.009 0.000 0.484 0.000 0.1556 0.009 0.001 0.685 0.000 0.2333 0.009 0.002 0.838 0.000 0.3111 0.009 0.003 0.968 0.000 0.3889 0.009 0.003 1.083 0.000 0.4667 0.009 0.004 1.186 0.000 0.5444 0.009 0.005 1.281 0.000 0.6222 0.009 0.006 1.370 0.000 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 103 0.7000 0.009 0.006 1.453 0.000 0.7778 0.009 0.007 1.531 0.000 0.8556 0.009 0.008 1.606 0.000 0.9333 0.009 0.009 1.677 0.000 1.0111 0.009 0.009 1.746 0.000 1.0889 0.009 0.010 1.812 0.000 1.1667 0.009 0.011 1.875 0.000 1.2444 0.009 0.012 1.937 0.000 1.3222 0.009 0.012 1.997 0.000 1.4000 0.009 0.013 2.055 0.000 1.4778 0.009 0.014 2.111 0.000 1.5556 0.009 0.015 2.166 0.000 1.6333 0.009 0.015 2.219 0.000 1.7111 0.009 0.016 2.271 0.000 1.7889 0.009 0.017 2.322 0.000 1.8667 0.009 0.018 2.372 0.000 1.9444 0.009 0.018 2.421 0.000 2.0222 0.009 0.019 2.469 0.000 2.1000 0.009 0.020 2.516 0.000 2.1778 0.009 0.021 2.563 0.000 2.2556 0.009 0.021 2.608 0.000 2.3333 0.009 0.022 2.652 0.000 2.4111 0.009 0.023 2.696 0.000 2.4889 0.009 0.024 2.739 0.000 2.5667 0.009 0.024 2.782 0.000 2.6444 0.009 0.025 2.824 0.000 2.7222 0.009 0.026 2.865 0.000 2.8000 0.009 0.027 2.906 0.000 2.8778 0.009 0.027 2.946 0.000 2.9556 0.009 0.028 2.985 0.000 3.0333 0.009 0.029 3.024 0.000 3.1111 0.009 0.030 3.063 0.000 3.1889 0.009 0.030 3.101 0.000 3.2667 0.009 0.031 3.139 0.000 3.3444 0.009 0.032 3.176 0.000 3.4222 0.009 0.033 3.212 0.000 3.5000 0.009 0.033 3.249 0.000 3.5778 0.009 0.034 3.285 0.000 3.6556 0.009 0.035 3.320 0.000 3.7333 0.009 0.036 3.355 0.000 3.8111 0.009 0.036 3.390 0.000 3.8889 0.009 0.037 3.424 0.000 3.9667 0.009 0.038 3.459 0.000 4.0444 0.009 0.039 3.492 0.000 4.1222 0.009 0.039 3.526 0.000 4.2000 0.009 0.040 3.559 0.000 4.2778 0.009 0.041 3.592 0.000 4.3556 0.009 0.042 3.624 0.000 4.4333 0.009 0.042 3.656 0.000 4.5111 0.009 0.043 3.688 0.000 4.5889 0.009 0.044 3.720 0.000 4.6667 0.009 0.045 3.751 0.000 4.7444 0.009 0.045 3.783 0.000 4.8222 0.009 0.046 3.813 0.000 4.9000 0.009 0.047 3.844 0.000 4.9778 0.009 0.048 3.874 0.000 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 104 5.0556 0.009 0.048 3.905 0.000 5.1333 0.009 0.049 3.934 0.000 5.2111 0.009 0.050 3.964 0.000 5.2889 0.009 0.051 3.994 0.000 5.3667 0.009 0.051 4.023 0.000 5.4444 0.009 0.052 4.052 0.000 5.5222 0.009 0.053 4.081 0.000 5.6000 0.009 0.054 4.109 0.000 5.6778 0.009 0.054 4.138 0.000 5.7556 0.009 0.055 4.166 0.000 5.8333 0.009 0.056 4.194 0.000 5.9111 0.009 0.057 4.222 0.000 5.9889 0.009 0.057 4.250 0.000 6.0667 0.009 0.058 4.277 0.000 6.1444 0.009 0.059 4.305 0.000 6.2222 0.009 0.060 4.332 0.000 6.3000 0.009 0.060 4.359 0.000 6.3778 0.009 0.061 4.386 0.000 6.4556 0.009 0.062 4.412 0.000 6.5333 0.009 0.063 4.439 0.000 6.6111 0.009 0.063 4.465 0.000 6.6889 0.009 0.064 4.491 0.000 6.7667 0.009 0.065 4.517 0.000 6.8444 0.009 0.066 4.543 0.000 6.9222 0.009 0.066 4.569 0.000 7.0000 0.009 0.067 4.595 0.000 ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.667 Total Impervious Area:0.511 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.109 Total Impervious Area:1.069 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.240286 5 year 0.325062 10 year 0.385779 25 year 0.467872 50 year 0.533031 100 year 0.601702 Flow Frequency Return Periods for Mitigated. POC #1 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 105 Return Period Flow(cfs) 2 year 0.409806 5 year 0.519353 10 year 0.593973 25 year 0.690961 50 year 0.765324 100 year 0.841598 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.349 0.521 1950 0.332 0.554 1951 0.216 0.335 1952 0.148 0.296 1953 0.160 0.317 1954 0.194 0.333 1955 0.210 0.383 1956 0.210 0.379 1957 0.264 0.429 1958 0.185 0.332 1959 0.165 0.336 1960 0.227 0.340 1961 0.218 0.371 1962 0.163 0.312 1963 0.211 0.350 1964 0.192 0.336 1965 0.279 0.451 1966 0.162 0.290 1967 0.336 0.493 1968 0.328 0.518 1969 0.253 0.406 1970 0.223 0.377 1971 0.267 0.444 1972 0.330 0.491 1973 0.142 0.276 1974 0.257 0.417 1975 0.270 0.469 1976 0.198 0.318 1977 0.187 0.343 1978 0.230 0.422 1979 0.290 0.547 1980 0.382 0.600 1981 0.242 0.425 1982 0.391 0.612 1983 0.258 0.499 1984 0.179 0.312 1985 0.245 0.431 1986 0.217 0.370 1987 0.293 0.577 1988 0.165 0.340 1989 0.206 0.388 1990 0.598 0.794 1991 0.434 0.567 1992 0.177 0.309 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 106 1993 0.141 0.267 1994 0.138 0.291 1995 0.210 0.376 1996 0.278 0.444 1997 0.251 0.396 1998 0.211 0.400 1999 0.520 0.803 2000 0.241 0.403 2001 0.224 0.427 2002 0.347 0.545 2003 0.270 0.392 2004 0.476 0.807 2005 0.220 0.360 2006 0.204 0.313 2007 0.540 0.662 2008 0.426 0.557 2009 0.266 0.560 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.5979 0.8074 2 0.5400 0.8026 3 0.5196 0.7939 4 0.4761 0.6625 5 0.4340 0.6123 6 0.4256 0.5996 7 0.3912 0.5770 8 0.3824 0.5672 9 0.3491 0.5600 10 0.3472 0.5566 11 0.3356 0.5542 12 0.3324 0.5473 13 0.3302 0.5449 14 0.3285 0.5212 15 0.2930 0.5183 16 0.2897 0.4986 17 0.2791 0.4927 18 0.2775 0.4907 19 0.2700 0.4686 20 0.2698 0.4513 21 0.2666 0.4442 22 0.2663 0.4436 23 0.2642 0.4313 24 0.2577 0.4295 25 0.2570 0.4273 26 0.2527 0.4251 27 0.2513 0.4221 28 0.2447 0.4170 29 0.2420 0.4064 30 0.2413 0.4031 31 0.2298 0.3997 32 0.2266 0.3962 33 0.2244 0.3918 34 0.2230 0.3877 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 107 35 0.2202 0.3832 36 0.2179 0.3787 37 0.2170 0.3771 38 0.2160 0.3764 39 0.2111 0.3709 40 0.2108 0.3704 41 0.2105 0.3605 42 0.2104 0.3503 43 0.2096 0.3432 44 0.2063 0.3403 45 0.2035 0.3401 46 0.1982 0.3363 47 0.1944 0.3363 48 0.1916 0.3345 49 0.1867 0.3334 50 0.1854 0.3321 51 0.1787 0.3177 52 0.1772 0.3172 53 0.1655 0.3125 54 0.1649 0.3123 55 0.1634 0.3120 56 0.1617 0.3093 57 0.1598 0.2961 58 0.1476 0.2909 59 0.1418 0.2898 60 0.1409 0.2757 61 0.1376 0.2665 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility FAILED Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.1201 1502 9199 612 Fail 0.1243 1350 8504 629 Fail 0.1285 1209 7786 644 Fail 0.1327 1078 7144 662 Fail 0.1368 975 6594 676 Fail 0.1410 885 6070 685 Fail 0.1452 770 5491 713 Fail 0.1493 704 5050 717 Fail 0.1535 640 4652 726 Fail 0.1577 584 4316 739 Fail 0.1618 539 4004 742 Fail 0.1660 474 3655 771 Fail 0.1702 441 3409 773 Fail 0.1744 408 3161 774 Fail 0.1785 383 2956 771 Fail 0.1827 358 2770 773 Fail 0.1869 326 2588 793 Fail 0.1910 302 2368 784 Fail 0.1952 286 2205 770 Fail 0.1994 264 2055 778 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 108 0.2036 253 1901 751 Fail 0.2077 233 1759 754 Fail 0.2119 210 1650 785 Fail 0.2161 192 1494 778 Fail 0.2202 172 1390 808 Fail 0.2244 155 1314 847 Fail 0.2286 150 1222 814 Fail 0.2327 140 1147 819 Fail 0.2369 135 1083 802 Fail 0.2411 126 1003 796 Fail 0.2453 119 940 789 Fail 0.2494 114 893 783 Fail 0.2536 107 835 780 Fail 0.2578 103 784 761 Fail 0.2619 99 736 743 Fail 0.2661 91 687 754 Fail 0.2703 87 653 750 Fail 0.2745 80 615 768 Fail 0.2786 77 586 761 Fail 0.2828 74 555 750 Fail 0.2870 72 527 731 Fail 0.2911 63 487 773 Fail 0.2953 60 467 778 Fail 0.2995 56 445 794 Fail 0.3036 54 422 781 Fail 0.3078 52 402 773 Fail 0.3120 50 386 772 Fail 0.3162 47 361 768 Fail 0.3203 46 344 747 Fail 0.3245 45 330 733 Fail 0.3287 43 312 725 Fail 0.3328 40 296 740 Fail 0.3370 33 270 818 Fail 0.3412 33 251 760 Fail 0.3454 32 240 750 Fail 0.3495 30 230 766 Fail 0.3537 28 218 778 Fail 0.3579 26 210 807 Fail 0.3620 25 202 808 Fail 0.3662 23 195 847 Fail 0.3704 23 188 817 Fail 0.3745 22 176 800 Fail 0.3787 21 158 752 Fail 0.3829 20 150 750 Fail 0.3871 18 145 805 Fail 0.3912 17 144 847 Fail 0.3954 15 139 926 Fail 0.3996 15 133 886 Fail 0.4037 15 122 813 Fail 0.4079 15 118 786 Fail 0.4121 15 116 773 Fail 0.4163 14 111 792 Fail 0.4204 12 109 908 Fail 0.4246 10 107 1070 Fail 0.4288 9 102 1133 Fail 0.4329 9 96 1066 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 109 0.4371 8 93 1162 Fail 0.4413 8 87 1087 Fail 0.4454 7 84 1200 Fail 0.4496 7 82 1171 Fail 0.4538 7 74 1057 Fail 0.4580 6 70 1166 Fail 0.4621 5 67 1340 Fail 0.4663 5 66 1320 Fail 0.4705 5 63 1260 Fail 0.4746 5 63 1260 Fail 0.4788 4 61 1525 Fail 0.4830 3 60 2000 Fail 0.4872 3 57 1900 Fail 0.4913 3 54 1800 Fail 0.4955 3 49 1633 Fail 0.4997 3 48 1600 Fail 0.5038 3 48 1600 Fail 0.5080 3 46 1533 Fail 0.5122 3 44 1466 Fail 0.5163 3 41 1366 Fail 0.5205 2 39 1950 Fail 0.5247 2 36 1800 Fail 0.5289 2 34 1700 Fail 0.5330 2 33 1650 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: 0.1349 acre-feet On-line facility target flow: 0.1724 cfs. Adjusted for 15 min: 0.1724 cfs. Off-line facility target flow: 0.0974 cfs. Adjusted for 15 min: 0.0974 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 Storm Capture 1 POC N 160.76 N 0.00 Total Volume Infiltrated 160.76 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 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 110 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. 2005-2023; All Rights Reserved. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 111 WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: 2022-12 19480 Brotherton Full-Site Flow Control Site Name: Brotherton Site Address: 215 SW 12th Street City : Renton Report Date: 3/15/2023 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 (adjusted) Precip Scale: 0.00 Version Date: 2021/08/18 Version : 4.2.18 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Buick-GMC-Predev Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .111 Pervious Total 0.111 Impervious Land Use acre SIDEWALKS FLAT 0.012 PARKING FLAT 0.233 Impervious Total 0.245 Basin Total 0.356 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : Cadillac-Not-Pumped-Predev Bypass: No GroundWater: No BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 112 Pervious Land Use acre C, Lawn, Flat .039 Pervious Total 0.039 Impervious Land Use acre SIDEWALKS FLAT 0.001 PARKING FLAT 0.18 Impervious Total 0.181 Basin Total 0.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : Cadillac-Pumped-Predev Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .667 Pervious Total 0.667 Impervious Land Use acre ROOF TOPS FLAT 0.179 SIDEWALKS FLAT 0.034 PARKING FLAT 0.298 Impervious Total 0.511 Basin Total 1.178 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Buick-GMC-Mit Bypass: Yes BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 113 GroundWater: No Pervious Land Use acre C, Lawn, Flat .084 Pervious Total 0.084 Impervious Land Use acre ROOF TOPS FLAT 0.102 SIDEWALKS FLAT 0.038 PARKING FLAT 0.132 Impervious Total 0.272 Basin Total 0.356 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : Cadillac-Not-Pumped-Mit Bypass: Yes GroundWater: No Pervious Land Use acre C, Lawn, Flat .006 Pervious Total 0.006 Impervious Land Use acre SIDEWALKS FLAT 0.032 PARKING FLAT 0.182 Impervious Total 0.214 Basin Total 0.22 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ Name : Cadillac-Pumped-Mit Bypass: No GroundWater: No Not-Pumped surface conditions are derived from the Figures at the end of Section A.5. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 114 Pervious Land Use acre C, Lawn, Flat .109 Pervious Total 0.109 Impervious Land Use acre ROOF TOPS FLAT 0.374 SIDEWALKS FLAT 0.039 PARKING FLAT 0.656 Impervious Total 1.069 Basin Total 1.178 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater Storm Capture 4 Storm Capture 4 ___________________________________________________________________ Name : Storm Capture 4 Facility Name: Storm Capture 4 Dimensions Depth: 7 ft. Length : 60 ft. Width : 7 ft. Discharge Structure Riser Height: 0 ft. Riser Diameter: 0 in. Orifice 1 Diameter: 12 in. Elevation: 0 ft. Element Flows To: Outlet 1 Outlet 2 ___________________________________________________________________ SCapture Hydraulic Table Stage(feet) Area(ac.) Volume(ac-ft.) Discharge(cfs) Infilt(cfs) 0.0000 0.009 0.000 0.000 0.000 0.0778 0.009 0.000 1.089 0.000 0.1556 0.009 0.001 1.541 0.000 0.2333 0.009 0.002 1.887 0.000 0.3111 0.009 0.003 2.179 0.000 0.3889 0.009 0.003 2.436 0.000 0.4667 0.009 0.004 2.669 0.000 0.5444 0.009 0.005 2.883 0.000 0.6222 0.009 0.006 3.082 0.000 0.7000 0.009 0.006 3.269 0.000 0.7778 0.009 0.007 3.446 0.000 0.8556 0.009 0.008 3.614 0.000 Pumped surface conditions are derived from the Figures at the end of Section A.5. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 115 0.9333 0.009 0.009 3.775 0.000 1.0111 0.009 0.009 3.929 0.000 1.0889 0.009 0.010 4.077 0.000 1.1667 0.009 0.011 4.220 0.000 1.2444 0.009 0.012 4.359 0.000 1.3222 0.009 0.012 4.493 0.000 1.4000 0.009 0.013 4.623 0.000 1.4778 0.009 0.014 4.750 0.000 1.5556 0.009 0.015 4.873 0.000 1.6333 0.009 0.015 4.994 0.000 1.7111 0.009 0.016 5.111 0.000 1.7889 0.009 0.017 5.226 0.000 1.8667 0.009 0.018 5.338 0.000 1.9444 0.009 0.018 5.449 0.000 2.0222 0.009 0.019 5.556 0.000 2.1000 0.009 0.020 5.662 0.000 2.1778 0.009 0.021 5.766 0.000 2.2556 0.009 0.021 5.868 0.000 2.3333 0.009 0.022 5.969 0.000 2.4111 0.009 0.023 6.067 0.000 2.4889 0.009 0.024 6.164 0.000 2.5667 0.009 0.024 6.260 0.000 2.6444 0.009 0.025 6.354 0.000 2.7222 0.009 0.026 6.447 0.000 2.8000 0.009 0.027 6.538 0.000 2.8778 0.009 0.027 6.629 0.000 2.9556 0.009 0.028 6.718 0.000 3.0333 0.009 0.029 6.805 0.000 3.1111 0.009 0.030 6.892 0.000 3.1889 0.009 0.030 6.978 0.000 3.2667 0.009 0.031 7.062 0.000 3.3444 0.009 0.032 7.146 0.000 3.4222 0.009 0.033 7.229 0.000 3.5000 0.009 0.033 7.310 0.000 3.5778 0.009 0.034 7.391 0.000 3.6556 0.009 0.035 7.471 0.000 3.7333 0.009 0.036 7.550 0.000 3.8111 0.009 0.036 7.628 0.000 3.8889 0.009 0.037 7.706 0.000 3.9667 0.009 0.038 7.782 0.000 4.0444 0.009 0.039 7.858 0.000 4.1222 0.009 0.039 7.933 0.000 4.2000 0.009 0.040 8.008 0.000 4.2778 0.009 0.041 8.082 0.000 4.3556 0.009 0.042 8.155 0.000 4.4333 0.009 0.042 8.227 0.000 4.5111 0.009 0.043 8.299 0.000 4.5889 0.009 0.044 8.371 0.000 4.6667 0.009 0.045 8.441 0.000 4.7444 0.009 0.045 8.511 0.000 4.8222 0.009 0.046 8.581 0.000 4.9000 0.009 0.047 8.650 0.000 4.9778 0.009 0.048 8.718 0.000 5.0556 0.009 0.048 8.786 0.000 5.1333 0.009 0.049 8.853 0.000 5.2111 0.009 0.050 8.920 0.000 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 116 5.2889 0.009 0.051 8.986 0.000 5.3667 0.009 0.051 9.052 0.000 5.4444 0.009 0.052 9.118 0.000 5.5222 0.009 0.053 9.182 0.000 5.6000 0.009 0.054 9.247 0.000 5.6778 0.009 0.054 9.311 0.000 5.7556 0.009 0.055 9.374 0.000 5.8333 0.009 0.056 9.438 0.000 5.9111 0.009 0.057 9.500 0.000 5.9889 0.009 0.057 9.563 0.000 6.0667 0.009 0.058 9.624 0.000 6.1444 0.009 0.059 9.686 0.000 6.2222 0.009 0.060 9.747 0.000 6.3000 0.009 0.060 9.808 0.000 6.3778 0.009 0.061 9.868 0.000 6.4556 0.009 0.062 9.928 0.000 6.5333 0.009 0.063 9.988 0.000 6.6111 0.009 0.063 10.04 0.000 6.6889 0.009 0.064 10.10 0.000 6.7667 0.009 0.065 10.16 0.000 6.8444 0.009 0.066 10.22 0.000 6.9222 0.009 0.066 10.28 0.000 7.0000 0.009 0.067 10.33 0.000 ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:0.817 Total Impervious Area:0.937 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.199 Total Impervious Area:1.555 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.41146 5 year 0.543838 10 year 0.636972 25 year 0.761139 50 year 0.858486 100 year 0.960094 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 0.604012 5 year 0.767173 WWHM used to determine full site 2-, 10-, and 100-year flow conditions. SSA was used to determine the developed conditions flow rates for the overall site. Disregard the WWHM Mitigated condition flow rates for this report. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 117 10 year 0.878503 25 year 1.023399 50 year 1.134625 100 year 1.248814 ___________________________________________________________________ Stream Protection Duration Annual Peaks for Predeveloped and Mitigated. POC #1 Year Predeveloped Mitigated 1949 0.581 0.791 1950 0.535 0.829 1951 0.361 0.495 1952 0.266 0.430 1953 0.288 0.467 1954 0.335 0.492 1955 0.367 0.555 1956 0.364 0.551 1957 0.446 0.631 1958 0.326 0.495 1959 0.303 0.499 1960 0.376 0.506 1961 0.371 0.540 1962 0.291 0.457 1963 0.359 0.514 1964 0.331 0.493 1965 0.468 0.655 1966 0.282 0.424 1967 0.539 0.733 1968 0.567 0.824 1969 0.424 0.593 1970 0.384 0.560 1971 0.458 0.667 1972 0.540 0.714 1973 0.248 0.409 1974 0.435 0.617 1975 0.452 0.689 1976 0.336 0.475 1977 0.319 0.505 1978 0.397 0.617 1979 0.524 0.839 1980 0.620 0.819 1981 0.420 0.625 1982 0.646 0.902 1983 0.458 0.728 1984 0.309 0.458 1985 0.423 0.631 1986 0.364 0.541 1987 0.524 0.839 1988 0.302 0.499 1989 0.378 0.611 1990 0.944 1.152 1991 0.700 0.882 1992 0.306 0.454 1993 0.250 0.389 1994 0.252 0.417 1995 0.368 0.556 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 118 1996 0.451 0.622 1997 0.421 0.584 1998 0.373 0.586 1999 0.872 1.211 2000 0.413 0.594 2001 0.404 0.642 2002 0.576 0.786 2003 0.447 0.586 2004 0.803 1.110 2005 0.370 0.525 2006 0.338 0.461 2007 0.848 1.049 2008 0.687 0.860 2009 0.464 0.780 ___________________________________________________________________ Stream Protection Duration Ranked Annual Peaks for Predeveloped and Mitigated. POC #1 Rank Predeveloped Mitigated 1 0.9438 1.2112 2 0.8720 1.1522 3 0.8481 1.1097 4 0.8035 1.0495 5 0.7004 0.9020 6 0.6872 0.8820 7 0.6455 0.8601 8 0.6199 0.8394 9 0.5812 0.8391 10 0.5755 0.8289 11 0.5671 0.8245 12 0.5405 0.8187 13 0.5394 0.7907 14 0.5348 0.7859 15 0.5243 0.7796 16 0.5238 0.7332 17 0.4676 0.7282 18 0.4640 0.7141 19 0.4583 0.6888 20 0.4579 0.6672 21 0.4524 0.6552 22 0.4508 0.6415 23 0.4475 0.6309 24 0.4457 0.6308 25 0.4350 0.6247 26 0.4241 0.6222 27 0.4234 0.6173 28 0.4214 0.6169 29 0.4204 0.6107 30 0.4128 0.5942 31 0.4036 0.5927 32 0.3966 0.5863 33 0.3837 0.5857 34 0.3781 0.5841 35 0.3762 0.5600 36 0.3734 0.5557 37 0.3712 0.5549 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 119 38 0.3704 0.5511 39 0.3677 0.5408 40 0.3668 0.5396 41 0.3643 0.5249 42 0.3641 0.5144 43 0.3606 0.5058 44 0.3595 0.5047 45 0.3383 0.4986 46 0.3358 0.4985 47 0.3345 0.4951 48 0.3308 0.4950 49 0.3256 0.4926 50 0.3187 0.4920 51 0.3087 0.4746 52 0.3060 0.4668 53 0.3032 0.4610 54 0.3023 0.4579 55 0.2910 0.4571 56 0.2879 0.4544 57 0.2822 0.4299 58 0.2662 0.4242 59 0.2523 0.4174 60 0.2496 0.4085 61 0.2485 0.3894 ___________________________________________________________________ Stream Protection Duration POC #1 The Facility FAILED Facility FAILED duration standard for 1+ flows. Flow(cfs) Predev Mit Percentage Pass/Fail 0.2057 1600 6004 375 Fail 0.2123 1430 5458 381 Fail 0.2189 1293 5024 388 Fail 0.2255 1154 4575 396 Fail 0.2321 1034 4171 403 Fail 0.2387 933 3841 411 Fail 0.2453 839 3523 419 Fail 0.2519 763 3290 431 Fail 0.2585 701 3022 431 Fail 0.2651 636 2787 438 Fail 0.2717 586 2586 441 Fail 0.2783 533 2383 447 Fail 0.2849 500 2220 444 Fail 0.2914 456 2032 445 Fail 0.2980 421 1865 442 Fail 0.3046 387 1730 447 Fail 0.3112 360 1606 446 Fail 0.3178 338 1467 434 Fail 0.3244 318 1354 425 Fail 0.3310 296 1268 428 Fail 0.3376 273 1183 433 Fail 0.3442 257 1080 420 Fail 0.3508 237 1006 424 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 120 0.3574 219 941 429 Fail 0.3640 207 890 429 Fail 0.3706 187 828 442 Fail 0.3772 172 777 451 Fail 0.3838 159 739 464 Fail 0.3903 151 676 447 Fail 0.3969 143 637 445 Fail 0.4035 132 599 453 Fail 0.4101 125 563 450 Fail 0.4167 118 536 454 Fail 0.4233 109 496 455 Fail 0.4299 105 469 446 Fail 0.4365 101 447 442 Fail 0.4431 98 420 428 Fail 0.4497 91 396 435 Fail 0.4563 84 379 451 Fail 0.4629 80 357 446 Fail 0.4695 72 337 468 Fail 0.4761 71 318 447 Fail 0.4827 70 299 427 Fail 0.4893 65 280 430 Fail 0.4958 63 266 422 Fail 0.5024 61 254 416 Fail 0.5090 57 235 412 Fail 0.5156 56 225 401 Fail 0.5222 54 218 403 Fail 0.5288 50 203 406 Fail 0.5354 43 191 444 Fail 0.5420 40 182 455 Fail 0.5486 38 172 452 Fail 0.5552 35 164 468 Fail 0.5618 33 155 469 Fail 0.5684 32 151 471 Fail 0.5750 30 145 483 Fail 0.5816 29 141 486 Fail 0.5882 27 130 481 Fail 0.5947 25 122 488 Fail 0.6013 24 113 470 Fail 0.6079 23 110 478 Fail 0.6145 22 106 481 Fail 0.6211 20 101 505 Fail 0.6277 20 97 485 Fail 0.6343 18 89 494 Fail 0.6409 17 87 511 Fail 0.6475 15 84 560 Fail 0.6541 15 83 553 Fail 0.6607 15 79 526 Fail 0.6673 14 76 542 Fail 0.6739 13 71 546 Fail 0.6805 11 69 627 Fail 0.6871 11 64 581 Fail 0.6936 10 63 630 Fail 0.7002 10 61 610 Fail 0.7068 7 61 871 Fail 0.7134 7 59 842 Fail 0.7200 7 55 785 Fail BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 121 0.7266 7 53 757 Fail 0.7332 7 52 742 Fail 0.7398 7 47 671 Fail 0.7464 7 45 642 Fail 0.7530 7 45 642 Fail 0.7596 7 42 600 Fail 0.7662 6 41 683 Fail 0.7728 5 39 780 Fail 0.7794 5 36 720 Fail 0.7860 5 33 660 Fail 0.7926 5 31 620 Fail 0.7991 5 31 620 Fail 0.8057 3 30 1000 Fail 0.8123 3 29 966 Fail 0.8189 3 26 866 Fail 0.8255 3 21 700 Fail 0.8321 3 19 633 Fail 0.8387 3 18 600 Fail 0.8453 3 15 500 Fail 0.8519 2 14 700 Fail 0.8585 2 14 700 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: 0.1341 acre-feet On-line facility target flow: 0.1686 cfs. Adjusted for 15 min: 0.1686 cfs. Off-line facility target flow: 0.0955 cfs. Adjusted for 15 min: 0.0955 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 Storm Capture 4 POC N 160.76 N 0.00 Total Volume Infiltrated 160.76 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. ___________________________________________________________________ BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 122 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. 2005-2023; All Rights Reserved. BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 123 A.8 SSA Reports BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 124 2-Year Storm Event Pipes: Element Description From (Inlet) To (Outlet) Length Inlet Outlet Average Peak Travel Max ID Node Node Invert Invert Slope Flow Time Flow Depth / Elevation Elevation Total Depth Ratio (ft) (ft) (ft) (%) (cfs) (min) {Storm-Buick- GMC}.Pipe - (34) (Sto rm-Buick-GMC) 8" DIP CB51 (Storm- Buick-GMC) BIOPOD UND ERGROUND B IOFILTER - 4X 4 (Storm- Buick-GMC) 16.94 19.66 19.48 1.0600 0.09 0.14 0.19 {Storm-Buick- GMC}.Pipe - (35) (Sto rm-Buick-GMC) 12" DIP BIOPOD UND ERGROUND BIOFILTER - 4 X4 (Storm- Buick-GMC) Structure - (42 ) (Storm- Buick-GMC) 58.88 18.98 18.69 0.4900 0.09 0.65 0.13 {Storm-Buick- GMC}.Pipe - (36) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO01 (Sto rm-Buick- GMC) RDCO02 (Stor m-Buick-GMC) 45.69 20.59 20.30 0.6300 0.02 0.66 0.16 {Storm-Buick- GMC}.Pipe - (37) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO02 (Sto rm-Buick- GMC) CB51 (Storm- Buick-GMC) 29.78 20.30 19.66 2.1500 0.05 0.32 0.21 {Storm-Buick- GMC}.Pipe - (38) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO03 (Sto rm-Buick- GMC) RDCO02 (Stor m-Buick-GMC) 46.32 20.93 20.30 1.3600 0.02 0.58 0.15 {Storm- Cadillac}.ByPass 12" DIP LIFT STATION (Storm- Cadillac) CB-B (Storm- Cadillac) 10.99 21.00 20.14 7.8500 0.00 0.03 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 125 {Storm- Cadillac}.Pipe - (100) (Storm-Cadillac) 12" DIP CB11 (Storm- Cadillac) CB-E (Storm- Cadillac) 27.97 19.35 18.88 1.6800 0.07 0.27 0.15 {Storm- Cadillac}.Pipe - (101) (Storm-Cadillac) 12" DIP CB02 (Storm- Cadillac) CB03 (Storm- Cadillac) 39.59 19.62 19.23 0.9800 0.04 0.63 0.10 {Storm- Cadillac}.Pipe - (103) (Storm-Cadillac) 12" DIP CB01 (Storm- Cadillac) CB02 (Storm- Cadillac) 69.37 20.30 19.62 0.9800 0.03 0.96 0.07 {Storm- Cadillac}.Pipe - (114) (Storm-Cadillac) 4" DIP DDCVA PUM P STATION (S torm- Cadillac) CB02 (Storm- Cadillac) 30.44 20.67 20.67 0.0000 0.00 0.00 {Storm- Cadillac}.Pipe - (115) (Storm-Cadillac) 6" PVC SDR35 DDCV ASSEM BLY (Storm- Cadillac) DDCVA PUMP STATION (Sto rm-Cadillac) 4.83 16.30 16.23 1.4700 0.00 0.00 {Storm- Cadillac}.Pipe - (128) (Storm-Cadillac) 12" CPP Structure - (1 50) (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 59.35 20.02 19.23 1.3300 0.07 1.48 0.19 {Storm- Cadillac}.Pipe - (16) ( Storm-Cadillac) 12" CPEP CB10 (Storm- Cadillac) CB08 (Storm- Cadillac) 120.85 17.91 16.73 0.9800 0.08 2.96 0.21 {Storm- Cadillac}.Pipe - (17) ( 1) (Storm-Cadillac) 12" CPEP PRETREATME NT (Storm- Cadillac) BIOPOD UND ERGROUND B IOFILTER - 6X 4 (Storm- Cadillac) 8.00 16.69 16.65 0.5000 0.34 0.07 0.27 {Storm- Cadillac}.Pipe - (17) ( Storm-Cadillac) 12" CPEP CB08 (Storm- Cadillac) PRETREATME NT (Storm- Cadillac) 8.00 16.73 16.69 0.5000 0.34 0.08 0.31 {Storm- Cadillac}.Pipe - (18) ( Storm-Cadillac) 12" CPEP BIOPOD UND ERGROUND BIOFILTER - 6 X4 (Storm- Cadillac) STORAGE(Sto rm-Cadillac) 37.00 16.15 15.97 0.4900 0.34 0.29 0.25 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 126 {Storm- Cadillac}.Pipe - (20) ( Storm-Cadillac) 12" CPEP STORAGE(St orm-Cadillac) LIFT STATION( Storm- Cadillac) 14.97 10.03 9.82 1.4000 0.48 0.12 1.00 {Storm- Cadillac}.Pipe - (22) ( Storm-Cadillac) 4" DIP VALVE VAUL T (Storm- Cadillac) FM Angle (Sto rm-Cadillac) 105.50 20.21 20.31 -0.0900 0.26 0.42 1.00 {Storm- Cadillac}.Pipe - (23) ( Storm-Cadillac) 6" DIP FM Angle (St orm-Cadillac) CB-C (Storm- Cadillac) 46.10 20.31 20.42 -0.2500 0.25 0.48 0.75 {Storm- Cadillac}.Pipe - (24) ( Storm-Cadillac) 12" DIP CB03 (Storm- Cadillac) CB04 (Storm- Cadillac) 110.97 19.23 18.14 0.9800 0.11 1.01 0.13 {Storm- Cadillac}.Pipe - (25) ( Storm-Cadillac) 12" CPEP CB04 (Storm- Cadillac) CB05 (Storm- Cadillac) 51.69 18.14 17.50 1.2400 0.16 0.42 0.15 {Storm- Cadillac}.Pipe - (26) ( Storm-Cadillac) 12" CPEP CB05 (Storm- Cadillac) CB06 (Storm- Cadillac) 90.63 17.50 17.05 0.5000 0.16 0.87 0.17 {Storm- Cadillac}.Pipe - (27) ( Storm-Cadillac) 12" CPEP CB06 (Storm- Cadillac) CB07 (Storm- Cadillac) 43.12 17.05 16.83 0.5000 0.16 0.58 0.21 {Storm- Cadillac}.Pipe - (28) ( Storm-Cadillac) 12" CPEP CB07 (Storm- Cadillac) CB08 (Storm- Cadillac) 21.03 16.83 16.73 0.5000 0.26 0.26 0.29 {Storm- Cadillac}.Pipe - (34) ( Storm-Cadillac) 12" CPEP CB09 (Storm- Cadillac) CB10 (Storm- Cadillac) 53.43 18.43 17.91 0.9800 0.04 0.75 0.09 {Storm- Cadillac}.Pipe - (4) (1) (Storm-Cadillac) 12" DIP CB-B (Storm- Cadillac) CB-C (Storm- Cadillac) 23.55 20.15 19.99 0.6700 0.01 2.07 0.13 {Storm- Cadillac}.Pipe - (5) (St orm-Cadillac) 12" DIP CB-C (Storm- Cadillac) CB-D (Storm- Cadillac) 102.92 19.99 19.30 0.6700 0.25 0.66 0.21 {Storm- Cadillac}.Pipe - (6) (1) (Storm-Cadillac) 12" DIP CB-E (Storm- Cadillac) CB-F (Storm- Cadillac) 39.25 18.88 18.62 0.6700 0.30 0.29 0.23 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 127 {Storm- Cadillac}.Pipe - (6) (St orm-Cadillac) 12" DIP CB-D (Storm- Cadillac) CB-E (Storm- Cadillac) 62.19 19.30 18.88 0.6700 0.25 0.49 0.22 {Storm- Cadillac}.Pipe - (71) ( Storm-Cadillac) 12" CPP CB11 (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 77.18 19.35 19.23 0.1600 0.07 1.89 0.18 {Storm- Cadillac}.Pipe - (80) ( Storm-Cadillac) 15" CPP CB-F (Storm- Cadillac) Structure - (92 ) (Storm- Cadillac) 153.33 18.46 17.10 0.8900 0.30 1.01 0.15 Junctions: Element Description Invert Ground/ Rim Peak Peak Maximum Maximum Minimum Average Total ID Elevation (Max) Inflow Lateral HGL Surcharge Freeboard HGL Time Elevation Inflow Elevation Depth Attained Elevation Flooded Attained Attained Attained (ft) (ft) (cfs) (cfs) (ft) (ft) (ft) (ft) (minutes) BIOPOD UNDERGRO UND BIOFILTER - 4X 4 (Storm-Buick-GMC) 18.98 23.02 0.09 0.00 19.11 0.00 3.90 19.03 0.00 BIOPOD UNDERGRO UND BIOFILTER - 6X 4 (Storm-Cadillac) TYPE 1 16.15 22.65 0.34 0.00 16.43 0.00 6.22 16.25 0.00 CB01 (Storm- Cadillac) TYPE 1 20.30 22.50 0.03 0.03 20.36 0.00 2.14 20.33 0.00 CB02 (Storm- Cadillac) TYPE 1 19.62 22.18 0.04 0.01 19.70 0.00 2.49 19.65 0.00 CB03 (Storm- Cadillac) TYPE 1 17.76 21.62 0.11 0.07 19.35 0.00 2.27 19.13 0.00 CB04 (Storm- Cadillac) TYPE 1 17.44 22.83 0.16 0.05 18.28 0.00 4.55 18.11 0.00 CB05 (Storm- Cadillac) TYPE 1 15.91 22.31 0.16 0.00 17.67 0.00 4.63 17.33 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 128 CB06 (Storm- Cadillac) TYPE 2-48" 17.05 22.21 0.16 0.00 17.21 0.00 5.00 17.11 0.00 CB07 (Storm- Cadillac) TYPE 2-48" 16.83 22.93 0.26 0.11 17.10 0.00 5.84 16.91 0.00 CB08 (Storm- Cadillac) TYPE 2-48" 14.93 22.94 0.34 0.00 17.05 0.00 5.88 16.61 0.00 CB09 (Storm- Cadillac) TYPE 1 17.21 21.53 0.04 0.04 18.51 0.00 3.02 18.28 0.00 CB10 (Storm- Cadillac) TYPE 1 17.40 21.88 0.08 0.04 18.01 0.00 3.86 17.88 0.00 CB11 (Storm- Cadillac) TYPE 1 19.35 23.21 0.07 0.00 19.44 0.00 3.77 19.38 0.00 CB51 (Storm-Buick- GMC) TYPE 1 19.66 22.85 0.09 0.04 19.79 0.00 3.06 19.71 0.00 CB-B (Storm- Cadillac) TYPE 1 20.14 22.80 0.01 0.00 20.20 0.00 2.60 20.15 0.00 CB-C (Storm-Cadillac) TYPE 2-54" 19.99 22.80 0.26 0.00 20.20 0.00 2.61 20.05 0.00 CB-D (Storm- Cadillac) TYPE 1 19.30 22.35 0.25 0.00 19.51 0.00 2.84 19.36 0.00 CB-E (Storm-Cadillac) TYPE 1 18.88 22.86 0.30 0.00 19.12 0.00 3.75 18.97 0.00 CB-F (Storm-Cadillac) TYPE 1 18.46 22.59 0.30 0.00 18.65 0.00 3.93 18.53 0.00 DDCV ASSEMBLY (St orm-Cadillac) TYPE 1 16.30 23.32 0.00 0.00 16.30 0.00 7.02 16.30 0.00 DDCVA PUMP STATI ON (Storm-Cadillac) TYPE 1 15.75 23.25 0.00 0.00 15.75 0.00 7.49 15.75 0.00 FM Angle (Storm- Cadillac) Null Structure 20.31 2500.00 0.26 0.00 20.82 0.00 2479.18 20.49 0.00 PRETREATMENT (Sto rm-Cadillac) TYPE 2-48" 16.69 22.79 0.34 0.00 16.99 0.00 5.81 16.79 0.00 RDCO01 (Storm- Buick-GMC) 6" CO 20.59 24.00 0.02 0.02 20.67 0.00 3.33 20.62 0.00 RDCO02 (Storm- Buick-GMC) 6" CO 20.30 23.96 0.05 0.00 20.38 0.00 3.58 20.33 0.00 RDCO03 (Storm- Buick-GMC) 6" CO 20.93 23.96 0.02 0.02 21.00 0.00 2.97 20.95 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 129 Structure - (150) (Sto rm-Cadillac) TYPE 1 20.02 21.30 0.07 0.07 20.11 0.00 1.19 20.06 0.00 Structure - (82) (Stor m-Cadillac) TYPE 1 19.23 21.72 0.07 0.00 19.52 0.00 2.20 19.39 0.00 VALVE VAULT (Stor m-Cadillac) TYPE 1 20.21 2500.00 0.28 0.00 26.93 0.00 2473.07 20.66 0.00 Subbasins: Element Description Area Drainage Weighted Total Total Peak Time ID Node ID Curve Precipitation Runoff Runoff of Number Concentration (acres) (inches) (inches) (cfs) (days hh:mm:ss) BuickEastParking 0.15 Structure - (150) (Storm-Cadillac) 97.80 2.00 1.75 0.07 0 00:05:00 Buick-Frontage 0.14 Structure - (42) (Storm-Buick-GMC) 90.81 2.00 1.15 0.04 0 00:05:00 BuickNorthRoof 0.05 RDCO01 (Storm-Buick-GMC) 98.00 2.00 1.77 0.02 0 00:05:00 Buick-Parking 0.12 CB51 (Storm-Buick-GMC) 94.60 2.00 1.44 0.04 0 00:05:00 BuickSouthRoof 0.05 RDCO03 (Storm-Buick-GMC) 98.00 2.00 1.77 0.02 0 00:05:00 CadillacFrontage 0.04 Structure - (92) (Storm-Cadillac) 98.00 2.00 1.76 0.02 0 00:05:00 CB01 0.06 CB01 (Storm-Cadillac) 98.00 2.00 1.77 0.03 0 00:05:00 CB02 0.03 CB02 (Storm-Cadillac) 93.91 2.00 1.35 0.01 0 00:05:00 CB03 0.13 CB03 (Storm-Cadillac) 97.49 2.00 1.72 0.06 0 00:05:00 CB04 0.12 CB04 (Storm-Cadillac) 95.75 2.00 1.55 0.05 0 00:05:00 CB07 0.25 CB07 (Storm-Cadillac) 96.31 2.00 1.60 0.11 0 00:05:00 CB09 0.10 CB09 (Storm-Cadillac) 95.96 2.00 1.57 0.04 0 00:05:00 CB10 0.09 CB10 (Storm-Cadillac) 96.03 2.00 1.57 0.04 0 00:05:00 CBF 0.01 CB-F (Storm-Cadillac) 98.00 2.00 0.41 0.00 0 00:05:00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 130 Roof 0.36 STORAGE(Storm-Cadillac) 98.00 2.00 1.77 0.17 0 00:05:00 SW Corner 0.02 Structure - (92) (Storm-Cadillac) 98.00 2.00 1.48 0.01 0 00:05:00 Trash 0.01 CB03 (Storm-Cadillac) 98.00 2.00 0.91 0.01 0 00:05:00 10-Year Storm Event Pipes: Element Description From (Inlet) To (Outlet) Length Inlet Inlet Average Peak Travel Max ID Node Node Invert Invert Slope Flow Time Flow Depth / Elevation Offset Total Depth Ratio (ft) (ft) (ft) (%) (cfs) (min) {Storm-Buick- GMC}.Pipe - (34) (Sto rm-Buick-GMC) 8" DIP CB51 (Storm- Buick-GMC) BIOPOD UND ERGROUND B IOFILTER - 4X 4 (Storm- Buick-GMC) 16.94 19.66 0.00 1.0600 0.14 0.13 0.24 {Storm-Buick- GMC}.Pipe - (35) (Sto rm-Buick-GMC) 12" DIP BIOPOD UN DERGROUN D BIOFILTER - 4X4 (Storm- Buick-GMC) Structure - (42 ) (Storm- Buick-GMC) 58.88 18.98 0.00 0.4900 0.14 0.58 0.16 {Storm-Buick- GMC}.Pipe - (36) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO01 (Sto rm-Buick- GMC) RDCO02 (Stor m-Buick-GMC) 45.69 20.59 0.00 0.6300 0.03 0.59 0.19 {Storm-Buick- GMC}.Pipe - (37) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO02 (Sto rm-Buick- GMC) CB51 (Storm- Buick-GMC) 29.78 20.30 0.00 2.1500 0.07 0.30 0.26 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 131 {Storm-Buick- GMC}.Pipe - (38) (Sto rm-Buick-GMC) 6" PVC SDR35 RDCO03 (Sto rm-Buick- GMC) RDCO02 (Stor m-Buick-GMC) 46.32 20.93 0.00 1.3600 0.03 0.52 0.17 {Storm- Cadillac}.ByPass 12" DIP LIFT STATIO N(Storm- Cadillac) CB-B (Storm- Cadillac) 10.99 21.00 11.18 7.8500 0.00 0.06 {Storm- Cadillac}.Pipe - (100) (Storm-Cadillac) 12" DIP CB11 (Storm- Cadillac) CB-E (Storm- Cadillac) 27.97 19.35 0.00 1.6800 0.10 0.34 0.19 {Storm- Cadillac}.Pipe - (101) (Storm-Cadillac) 12" DIP CB02 (Storm- Cadillac) CB03 (Storm- Cadillac) 39.59 19.62 0.00 0.9800 0.06 0.56 0.12 {Storm- Cadillac}.Pipe - (103) (Storm-Cadillac) 12" DIP CB01 (Storm- Cadillac) CB02 (Storm- Cadillac) 69.37 20.30 0.00 0.9800 0.04 0.86 0.08 {Storm- Cadillac}.Pipe - (114) (Storm-Cadillac) 4" DIP DDCVA PUM P STATION (S torm- Cadillac) CB02 (Storm- Cadillac) 30.44 20.67 4.91 0.0000 0.00 0.00 {Storm- Cadillac}.Pipe - (115) (Storm-Cadillac) 6" PVC SDR35 DDCV ASSEM BLY (Storm- Cadillac) DDCVA PUMP STATION (Sto rm-Cadillac) 4.83 16.30 0.00 1.4700 0.00 0.00 {Storm- Cadillac}.Pipe - (128) (Storm-Cadillac) 12" CPP Structure - (1 50) (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 59.35 20.02 0.00 1.3300 0.10 1.24 0.21 {Storm- Cadillac}.Pipe - (16) ( Storm-Cadillac) 12" CPEP CB10 (Storm- Cadillac) CB08 (Storm- Cadillac) 120.85 17.91 0.51 0.9800 0.12 2.65 0.27 {Storm- Cadillac}.Pipe - (17) ( 1) (Storm-Cadillac) 12" CPEP PRETREATM ENT (Storm- Cadillac) BIOPOD UND ERGROUND B IOFILTER - 6X 4 (Storm- Cadillac) 8.00 16.69 0.00 0.5000 0.52 0.06 0.33 {Storm- Cadillac}.Pipe - (17) ( Storm-Cadillac) 12" CPEP CB08 (Storm- Cadillac) PRETREATME NT (Storm- Cadillac) 8.00 16.73 1.80 0.5000 0.52 0.07 0.39 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 132 {Storm- Cadillac}.Pipe - (18) ( Storm-Cadillac) 12" CPEP BIOPOD UN DERGROUN D BIOFILTER - 6X4 (Storm- Cadillac) STORAGE(Sto rm-Cadillac) 37.00 16.15 0.00 0.4900 0.52 0.26 0.32 {Storm- Cadillac}.Pipe - (20) ( Storm-Cadillac) 12" CPEP STORAGE(St orm-Cadillac) LIFT STATION (Storm- Cadillac) 14.97 10.03 0.06 1.4000 0.47 0.10 1.00 {Storm- Cadillac}.Pipe - (22) ( Storm-Cadillac) 4" DIP VALVE VAUL T (Storm- Cadillac) FM Angle (Sto rm-Cadillac) 105.50 20.21 0.00 -0.0900 0.39 0.39 1.00 {Storm- Cadillac}.Pipe - (23) ( Storm-Cadillac) 6" DIP FM Angle (St orm-Cadillac) CB-C (Storm- Cadillac) 46.10 20.31 0.00 -0.2500 0.40 0.33 0.82 {Storm- Cadillac}.Pipe - (24) ( Storm-Cadillac) 12" DIP CB03 (Storm- Cadillac) CB04 (Storm- Cadillac) 110.97 19.23 1.47 0.9800 0.16 0.91 0.16 {Storm- Cadillac}.Pipe - (25) ( Storm-Cadillac) 12" CPEP CB04 (Storm- Cadillac) CB05 (Storm- Cadillac) 51.69 18.14 0.70 1.2400 0.23 0.38 0.19 {Storm- Cadillac}.Pipe - (26) ( Storm-Cadillac) 12" CPEP CB05 (Storm- Cadillac) CB06 (Storm- Cadillac) 90.63 17.50 1.59 0.5000 0.23 0.77 0.21 {Storm- Cadillac}.Pipe - (27) ( Storm-Cadillac) 12" CPEP CB06 (Storm- Cadillac) CB07 (Storm- Cadillac) 43.12 17.05 0.00 0.5000 0.23 0.55 0.28 {Storm- Cadillac}.Pipe - (28) ( Storm-Cadillac) 12" CPEP CB07 (Storm- Cadillac) CB08 (Storm- Cadillac) 21.03 16.83 0.00 0.5000 0.40 0.25 0.38 {Storm- Cadillac}.Pipe - (34) ( Storm-Cadillac) 12" CPEP CB09 (Storm- Cadillac) CB10 (Storm- Cadillac) 53.43 18.43 1.22 0.9800 0.06 0.66 0.11 {Storm- Cadillac}.Pipe - (4) (1 ) (Storm-Cadillac) 12" DIP CB-B (Storm- Cadillac) CB-C (Storm- Cadillac) 23.55 20.15 0.01 0.6700 0.03 1.03 0.18 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 133 {Storm- Cadillac}.Pipe - (5) (S torm-Cadillac) 12" DIP CB-C (Storm- Cadillac) CB-D (Storm- Cadillac) 102.92 19.99 0.00 0.6700 0.40 0.66 0.26 {Storm- Cadillac}.Pipe - (6) (1 ) (Storm-Cadillac) 12" DIP CB-E (Storm- Cadillac) CB-F (Storm- Cadillac) 39.25 18.88 0.00 0.6700 0.46 0.26 0.28 {Storm- Cadillac}.Pipe - (6) (S torm-Cadillac) 12" DIP CB-D (Storm- Cadillac) CB-E (Storm- Cadillac) 62.19 19.30 0.00 0.6700 0.40 0.46 0.28 {Storm- Cadillac}.Pipe - (71) ( Storm-Cadillac) 12" CPP CB11 (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 77.18 19.35 0.00 0.1600 0.10 1.59 0.21 {Storm- Cadillac}.Pipe - (80) ( Storm-Cadillac) 15" CPP CB-F (Storm- Cadillac) Structure - (92 ) (Storm- Cadillac) 153.33 18.46 0.00 0.8900 0.46 0.89 0.19 Junctions: Element Description Invert Ground/ Rim Peak Peak Maximum Maximum Minimum Average Total ID Elevation (Max) Inflow Lateral HGL Surcharge Freeboard HGL Time Elevation Inflow Elevation Depth Attained Elevation Flooded Attained Attained Attained (ft) (ft) (cfs) (cfs) (ft) (ft) (ft) (ft) (minutes) BIOPOD UNDERGRO UND BIOFILTER - 4X 4 (Storm-Buick-GMC) 18.98 23.02 0.14 0.00 19.14 0.00 3.87 19.04 0.00 BIOPOD UNDERGRO UND BIOFILTER - 6X 4 (Storm-Cadillac) TYPE 1 16.15 22.65 0.52 0.00 16.50 0.00 6.15 16.27 0.00 CB01 (Storm- Cadillac) TYPE 1 20.30 22.50 0.04 0.04 20.38 0.00 2.12 20.33 0.00 CB02 (Storm- Cadillac) TYPE 1 19.62 22.18 0.06 0.02 19.71 0.00 2.47 19.66 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 134 CB03 (Storm- Cadillac) TYPE 1 17.76 21.62 0.16 0.10 19.38 0.00 2.24 19.18 0.00 CB04 (Storm- Cadillac) TYPE 1 17.44 22.83 0.23 0.08 18.31 0.00 4.52 18.14 0.00 CB05 (Storm- Cadillac) TYPE 1 15.91 22.31 0.23 0.00 17.71 0.00 4.59 17.41 0.00 CB06 (Storm- Cadillac) TYPE 2-48" 17.05 22.21 0.23 0.00 17.25 0.00 4.96 17.12 0.00 CB07 (Storm- Cadillac) TYPE 2-48" 16.83 22.93 0.40 0.16 17.18 0.00 5.75 16.93 0.00 CB08 (Storm- Cadillac) TYPE 2-48" 14.93 22.94 0.52 0.00 17.14 0.00 5.80 16.69 0.00 CB09 (Storm- Cadillac) TYPE 1 17.21 21.53 0.06 0.06 18.52 0.00 3.00 18.33 0.00 CB10 (Storm- Cadillac) TYPE 1 17.40 21.88 0.12 0.06 18.04 0.00 3.84 17.91 0.00 CB11 (Storm- Cadillac) TYPE 1 19.35 23.21 0.10 0.00 19.45 0.00 3.75 19.39 0.00 CB51 (Storm-Buick- GMC) TYPE 1 19.66 22.85 0.14 0.07 19.82 0.00 3.03 19.72 0.00 CB-B (Storm- Cadillac) TYPE 1 20.14 22.80 0.03 0.00 20.25 0.00 2.55 20.17 0.00 CB-C (Storm- Cadillac) TYPE 2-54" 19.99 22.80 0.40 0.00 20.25 0.00 2.55 20.08 0.00 CB-D (Storm- Cadillac) TYPE 1 19.30 22.35 0.40 0.00 19.56 0.00 2.79 19.39 0.00 CB-E (Storm- Cadillac) TYPE 1 18.88 22.86 0.46 0.00 19.18 0.00 3.69 19.01 0.00 CB-F (Storm- Cadillac) TYPE 1 18.46 22.59 0.46 0.00 18.70 0.00 3.89 18.56 0.00 DDCV ASSEMBLY (St orm-Cadillac) TYPE 1 16.30 23.32 0.00 0.00 16.30 0.00 7.02 16.30 0.00 DDCVA PUMP STATI ON (Storm-Cadillac) TYPE 1 15.75 23.25 0.00 0.00 15.75 0.00 7.49 15.75 0.00 FM Angle (Storm- Cadillac) Null Structure 20.31 2500.00 0.39 0.00 21.19 0.00 2478.81 20.57 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 135 PRETREATMENT (St orm-Cadillac) TYPE 2-48" 16.69 22.79 0.52 0.00 17.06 0.00 5.73 16.82 0.00 RDCO01 (Storm- Buick-GMC) 6" CO 20.59 24.00 0.03 0.03 20.68 0.00 3.32 20.62 0.00 RDCO02 (Storm- Buick-GMC) 6" CO 20.30 23.96 0.07 0.00 20.40 0.00 3.56 20.34 0.00 RDCO03 (Storm- Buick-GMC) 6" CO 20.93 23.96 0.03 0.03 21.01 0.00 2.96 20.96 0.00 Structure - (150) (Sto rm-Cadillac) TYPE 1 20.02 21.30 0.10 0.10 20.13 0.00 1.17 20.06 0.00 Structure - (82) (Stor m-Cadillac) TYPE 1 19.23 21.72 0.10 0.00 19.56 0.00 2.16 19.41 0.00 VALVE VAULT (Stor m-Cadillac) TYPE 1 20.21 2500.00 0.39 0.00 26.92 0.00 2473.08 21.03 0.00 Subbasins: Element Description Area Drainage Weighted Total Total Peak Time ID Node ID Curve Precipitation Runoff Runoff of Number Concentration (acres) (inches) (inches) (cfs) (days hh:mm:ss) BuickEastParking 0.15 Structure - (150) (Storm-Cadillac) 97.80 2.85 2.60 0.10 0 00:05:00 Buick-Frontage 0.14 Structure - (42) (Storm-Buick-GMC) 90.81 2.85 1.91 0.07 0 00:05:00 BuickNorthRoof 0.05 RDCO01 (Storm-Buick-GMC) 98.00 2.85 2.62 0.03 0 00:05:00 Buick-Parking 0.12 CB51 (Storm-Buick-GMC) 94.60 2.85 2.26 0.07 0 00:05:00 BuickSouthRoof 0.05 RDCO03 (Storm-Buick-GMC) 98.00 2.85 2.62 0.03 0 00:05:00 CadillacFrontage 0.04 Structure - (92) (Storm-Cadillac) 98.00 2.85 2.61 0.03 0 00:05:00 CB01 0.06 CB01 (Storm-Cadillac) 98.00 2.85 2.62 0.04 0 00:05:00 CB02 0.03 CB02 (Storm-Cadillac) 93.91 2.85 2.17 0.02 0 00:05:00 CB03 0.13 CB03 (Storm-Cadillac) 97.49 2.85 2.56 0.09 0 00:05:00 CB04 0.12 CB04 (Storm-Cadillac) 95.75 2.85 2.38 0.08 0 00:05:00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 136 CB07 0.25 CB07 (Storm-Cadillac) 96.31 2.85 2.44 0.16 0 00:05:00 CB09 0.10 CB09 (Storm-Cadillac) 95.96 2.85 2.40 0.06 0 00:05:00 CB10 0.09 CB10 (Storm-Cadillac) 96.03 2.85 2.41 0.06 0 00:05:00 CBF 0.01 CB-F (Storm-Cadillac) 98.00 2.85 0.97 0.00 0 00:05:00 Roof 0.36 STORAGE(Storm-Cadillac) 98.00 2.85 2.62 0.24 0 00:05:00 SW Corner 0.02 Structure - (92) (Storm-Cadillac) 98.00 2.85 2.58 0.01 0 00:05:00 Trash 0.01 CB03 (Storm-Cadillac) 98.00 2.85 2.12 0.01 0 00:05:00 100-Year Storm Event Pipes: Element Description From (Inlet) To (Outlet) Length Inlet Inlet Average Peak Travel Max ID Node Node Invert Invert Slope Flow Time Flow Depth / Elevation Offset Total Depth Ratio (ft) (ft) (ft) (%) (cfs) (min) {Storm-Buick- GMC}.Pipe - (34) (St orm-Buick-GMC) 8" DIP CB51 (Storm- Buick-GMC) BIOPOD UND ERGROUND B IOFILTER - 4X 4 (Storm- Buick-GMC) 16.94 19.66 0.00 1.0600 0.20 0.12 0.29 {Storm-Buick- GMC}.Pipe - (35) (St orm-Buick-GMC) 12" DIP BIOPOD UND ERGROUND B IOFILTER - 4X 4 (Storm- Buick-GMC) Structure - (42 ) (Storm- Buick-GMC) 58.88 18.98 0.00 0.4900 0.20 0.52 0.19 {Storm-Buick- GMC}.Pipe - (36) (St orm-Buick-GMC) 6" PVC SDR35 RDCO01 (Stor m-Buick-GMC) RDCO02 (Stor m-Buick-GMC) 45.69 20.59 0.00 0.6300 0.05 0.54 0.23 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 137 {Storm-Buick- GMC}.Pipe - (37) (St orm-Buick-GMC) 6" PVC SDR35 RDCO02 (Stor m-Buick-GMC) CB51 (Storm- Buick-GMC) 29.78 20.30 0.00 2.1500 0.10 0.28 0.32 {Storm-Buick- GMC}.Pipe - (38) (St orm-Buick-GMC) 6" PVC SDR35 RDCO03 (Stor m-Buick-GMC) RDCO02 (Stor m-Buick-GMC) 46.32 20.93 0.00 1.3600 0.05 0.47 0.21 {Storm- Cadillac}.ByPass 12" DIP LIFT STATION( Storm- Cadillac) CB-B (Storm- Cadillac) 10.99 21.00 11.18 7.8500 0.00 0.09 {Storm- Cadillac}.Pipe - (100) (Storm-Cadillac) 12" DIP CB11 (Storm- Cadillac) CB-E (Storm- Cadillac) 27.97 19.35 0.00 1.6800 0.15 0.34 0.24 {Storm- Cadillac}.Pipe - (101) (Storm-Cadillac) 12" DIP CB02 (Storm- Cadillac) CB03 (Storm- Cadillac) 39.59 19.62 0.00 0.9800 0.09 0.50 0.14 {Storm- Cadillac}.Pipe - (103) (Storm-Cadillac) 12" DIP CB01 (Storm- Cadillac) CB02 (Storm- Cadillac) 69.37 20.30 0.00 0.9800 0.06 0.78 0.10 {Storm- Cadillac}.Pipe - (114) (Storm-Cadillac) 4" DIP DDCVA PUMP STATION (Sto rm-Cadillac) CB02 (Storm- Cadillac) 30.44 20.67 4.91 0.0000 0.00 0.00 {Storm- Cadillac}.Pipe - (115) (Storm-Cadillac) 6" PVC SDR35 DDCV ASSEM BLY (Storm- Cadillac) DDCVA PUMP STATION (Sto rm-Cadillac) 4.83 16.30 0.00 1.4700 0.00 0.00 {Storm- Cadillac}.Pipe - (128) (Storm-Cadillac) 12" CPP Structure - (15 0) (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 59.35 20.02 0.00 1.3300 0.15 1.06 0.25 {Storm- Cadillac}.Pipe - (16) ( Storm-Cadillac) 12" CPEP CB10 (Storm- Cadillac) CB08 (Storm- Cadillac) 120.85 17.91 0.51 0.9800 0.18 2.49 0.33 {Storm- Cadillac}.Pipe - (17) ( 1) (Storm-Cadillac) 12" CPEP PRETREATME NT (Storm- Cadillac) BIOPOD UND ERGROUND B IOFILTER - 6X 4 (Storm- Cadillac) 8.00 16.69 0.00 0.5000 0.76 0.05 0.40 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 138 {Storm- Cadillac}.Pipe - (17) ( Storm-Cadillac) 12" CPEP CB08 (Storm- Cadillac) PRETREATME NT (Storm- Cadillac) 8.00 16.73 1.80 0.5000 0.76 0.07 0.48 {Storm- Cadillac}.Pipe - (18) ( Storm-Cadillac) 12" CPEP BIOPOD UND ERGROUND B IOFILTER - 6X 4 (Storm- Cadillac) STORAGE(Sto rm-Cadillac) 37.00 16.15 0.00 0.4900 0.76 0.24 0.52 {Storm- Cadillac}.Pipe - (20) ( Storm-Cadillac) 12" CPEP STORAGE(Sto rm-Cadillac) LIFT STATION( Storm- Cadillac) 14.97 10.03 0.06 1.4000 0.70 0.09 1.00 {Storm- Cadillac}.Pipe - (22) ( Storm-Cadillac) 4" DIP VALVE VAULT (Storm- Cadillac) FM Angle (Sto rm-Cadillac) 105.50 20.21 0.00 -0.0900 0.60 0.26 1.00 {Storm- Cadillac}.Pipe - (23) ( Storm-Cadillac) 6" DIP FM Angle (Sto rm-Cadillac) CB-C (Storm- Cadillac) 46.10 20.31 0.00 -0.2500 0.60 0.24 0.89 {Storm- Cadillac}.Pipe - (24) ( Storm-Cadillac) 12" DIP CB03 (Storm- Cadillac) CB04 (Storm- Cadillac) 110.97 19.23 1.47 0.9800 0.23 0.83 0.19 {Storm- Cadillac}.Pipe - (25) ( Storm-Cadillac) 12" CPEP CB04 (Storm- Cadillac) CB05 (Storm- Cadillac) 51.69 18.14 0.70 1.2400 0.34 0.34 0.22 {Storm- Cadillac}.Pipe - (26) ( Storm-Cadillac) 12" CPEP CB05 (Storm- Cadillac) CB06 (Storm- Cadillac) 90.63 17.50 1.59 0.5000 0.34 0.74 0.26 {Storm- Cadillac}.Pipe - (27) ( Storm-Cadillac) 12" CPEP CB06 (Storm- Cadillac) CB07 (Storm- Cadillac) 43.12 17.05 0.00 0.5000 0.34 0.54 0.36 {Storm- Cadillac}.Pipe - (28) ( Storm-Cadillac) 12" CPEP CB07 (Storm- Cadillac) CB08 (Storm- Cadillac) 21.03 16.83 0.00 0.5000 0.57 0.23 0.48 {Storm- Cadillac}.Pipe - (34) ( Storm-Cadillac) 12" CPEP CB09 (Storm- Cadillac) CB10 (Storm- Cadillac) 53.43 18.43 1.22 0.9800 0.09 0.59 0.13 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 139 {Storm- Cadillac}.Pipe - (4) (1 ) (Storm-Cadillac) 12" DIP CB-B (Storm- Cadillac) CB-C (Storm- Cadillac) 23.55 20.15 0.01 0.6700 0.05 0.64 0.25 {Storm- Cadillac}.Pipe - (5) (S torm-Cadillac) 12" DIP CB-C (Storm- Cadillac) CB-D (Storm- Cadillac) 102.92 19.99 0.00 0.6700 0.60 0.62 0.33 {Storm- Cadillac}.Pipe - (6) (1 ) (Storm-Cadillac) 12" DIP CB-E (Storm- Cadillac) CB-F (Storm- Cadillac) 39.25 18.88 0.00 0.6700 0.71 0.23 0.36 {Storm- Cadillac}.Pipe - (6) (S torm-Cadillac) 12" DIP CB-D (Storm- Cadillac) CB-E (Storm- Cadillac) 62.19 19.30 0.00 0.6700 0.60 0.41 0.35 {Storm- Cadillac}.Pipe - (71) ( Storm-Cadillac) 12" CPP CB11 (Storm- Cadillac) Structure - (82 ) (Storm- Cadillac) 77.18 19.35 0.00 0.1600 0.15 1.35 0.24 {Storm- Cadillac}.Pipe - (80) ( Storm-Cadillac) 15" CPP CB-F (Storm- Cadillac) Structure - (92 ) (Storm- Cadillac) 153.33 18.46 0.00 0.8900 0.71 0.79 0.24 Junctions: Element Description Invert Ground/ Rim Peak Peak Maximum Maximum Minimum Average Total ID Elevation (Max) Inflow Lateral HGL Surcharge Freeboard HGL Time Elevation Inflow Elevation Depth Attained Elevation Flooded Attained Attained Attained (ft) (ft) (cfs) (cfs) (ft) (ft) (ft) (ft) (minutes) BIOPOD UNDERGRO UND BIOFILTER - 4X 4 (Storm-Buick-GMC) 18.98 23.02 0.20 0.00 19.18 0.00 3.84 19.06 0.00 BIOPOD UNDERGRO UND BIOFILTER - 6X 4 (Storm-Cadillac) TYPE 1 16.15 22.65 0.76 0.00 16.60 0.00 6.04 16.30 0.00 CB01 (Storm- Cadillac) TYPE 1 20.30 22.50 0.06 0.06 20.39 0.00 2.11 20.34 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 140 CB02 (Storm- Cadillac) TYPE 1 19.62 22.18 0.09 0.03 19.73 0.00 2.45 19.66 0.00 CB03 (Storm- Cadillac) TYPE 1 17.76 21.62 0.23 0.14 19.40 0.00 2.21 19.21 0.00 CB04 (Storm- Cadillac) TYPE 1 17.44 22.83 0.34 0.11 18.35 0.00 4.48 18.17 0.00 CB05 (Storm- Cadillac) TYPE 1 15.91 22.31 0.34 0.00 17.75 0.00 4.55 17.46 0.00 CB06 (Storm- Cadillac) TYPE 2-48" 17.05 22.21 0.34 0.00 17.33 0.00 4.88 17.14 0.00 CB07 (Storm- Cadillac) TYPE 2-48" 16.83 22.93 0.57 0.24 17.29 0.00 5.65 16.96 0.00 CB08 (Storm- Cadillac) TYPE 2-48" 14.93 22.94 0.76 0.00 17.24 0.00 5.70 16.76 0.00 CB09 (Storm- Cadillac) TYPE 1 17.21 21.53 0.09 0.09 18.54 0.00 2.99 18.37 0.00 CB10 (Storm- Cadillac) TYPE 1 17.40 21.88 0.18 0.09 18.06 0.00 3.82 17.93 0.00 CB11 (Storm- Cadillac) TYPE 1 19.35 23.21 0.15 0.00 19.47 0.00 3.74 19.40 0.00 CB51 (Storm-Buick- GMC) TYPE 1 19.66 22.85 0.20 0.10 19.86 0.00 2.99 19.73 0.00 CB-B (Storm- Cadillac) TYPE 1 20.14 22.80 0.05 0.00 20.32 0.00 2.48 20.18 0.00 CB-C (Storm- Cadillac) TYPE 2-54" 19.99 22.80 0.62 0.00 20.32 0.00 2.49 20.11 0.00 CB-D (Storm- Cadillac) TYPE 1 19.30 22.35 0.60 0.00 19.63 0.00 2.72 19.42 0.00 CB-E (Storm- Cadillac) TYPE 1 18.88 22.86 0.71 0.00 19.26 0.00 3.60 19.04 0.00 CB-F (Storm- Cadillac) TYPE 1 18.46 22.59 0.71 0.01 18.76 0.00 3.83 18.59 0.00 DDCV ASSEMBLY (St orm-Cadillac) TYPE 1 16.30 23.32 0.00 0.00 16.30 0.00 7.02 16.30 0.00 DDCVA PUMP STATI ON (Storm-Cadillac) TYPE 1 15.75 23.25 0.00 0.00 15.75 0.00 7.49 15.75 0.00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 141 FM Angle (Storm- Cadillac) Null Structure 20.31 2500.00 0.60 0.00 21.42 0.00 2478.58 20.65 0.00 PRETREATMENT (St orm-Cadillac) TYPE 2-48" 16.69 22.79 0.76 0.00 17.15 0.00 5.64 16.85 0.00 RDCO01 (Storm- Buick-GMC) 6" CO 20.59 24.00 0.05 0.05 20.70 0.00 3.30 20.63 0.00 RDCO02 (Storm- Buick-GMC) 6" CO 20.30 23.96 0.10 0.00 20.42 0.00 3.54 20.34 0.00 RDCO03 (Storm- Buick-GMC) 6" CO 20.93 23.96 0.05 0.05 21.02 0.00 2.94 20.97 0.00 Structure - (150) (Sto rm-Cadillac) TYPE 1 20.02 21.30 0.15 0.15 20.15 0.00 1.15 20.07 0.00 Structure - (82) (Stor m-Cadillac) TYPE 1 19.23 21.72 0.15 0.00 19.60 0.00 2.12 19.43 0.00 VALVE VAULT (Stor m-Cadillac) TYPE 1 20.21 2500.00 0.60 0.00 27.09 0.00 2472.91 21.50 0.00 Subbasins: Element Description Area Drainage Weighted Total Total Peak Time ID Node ID Curve Precipitation Runoff Runoff of Number Concentration (acres) (inches) (inches) (cfs) (days hh:mm:ss) BuickEastParking 0.15 Structure - (150) (Storm-Cadillac) 97.80 4.00 3.74 0.15 0 00:05:00 Buick-Frontage 0.14 Structure - (42) (Storm-Buick-GMC) 90.81 4.00 3.00 0.11 0 00:05:00 BuickNorthRoof 0.05 RDCO01 (Storm-Buick-GMC) 98.00 4.00 3.76 0.05 0 00:05:00 Buick-Parking 0.12 CB51 (Storm-Buick-GMC) 94.60 4.00 3.39 0.10 0 00:05:00 BuickSouthRoof 0.05 RDCO03 (Storm-Buick-GMC) 98.00 4.00 3.76 0.05 0 00:05:00 CadillacFrontage 0.04 Structure - (92) (Storm-Cadillac) 98.00 4.00 3.76 0.04 0 00:05:00 CB01 0.06 CB01 (Storm-Cadillac) 98.00 4.00 3.76 0.06 0 00:05:00 CB02 0.03 CB02 (Storm-Cadillac) 93.91 4.00 3.30 0.03 0 00:05:00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 142 CB03 0.13 CB03 (Storm-Cadillac) 97.49 4.00 3.71 0.13 0 00:05:00 CB04 0.12 CB04 (Storm-Cadillac) 95.75 4.00 3.51 0.11 0 00:05:00 CB07 0.25 CB07 (Storm-Cadillac) 96.31 4.00 3.57 0.24 0 00:05:00 CB09 0.10 CB09 (Storm-Cadillac) 95.96 4.00 3.54 0.09 0 00:05:00 CB10 0.09 CB10 (Storm-Cadillac) 96.03 4.00 3.54 0.09 0 00:05:00 CBF 0.01 CB-F (Storm-Cadillac) 98.00 4.00 1.97 0.01 0 00:05:00 Roof 0.36 STORAGE(Storm-Cadillac) 98.00 4.00 3.77 0.35 0 00:05:00 SW Corner 0.02 Structure - (92) (Storm-Cadillac) 98.00 4.00 3.75 0.02 0 00:05:00 Trash 0.01 CB03 (Storm-Cadillac) 98.00 4.00 3.68 0.01 0 00:05:00 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 143 A.9 Water Quality GULDs BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 144 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 145 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 146 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 147 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 148 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 149 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 150 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 151 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 152 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 153 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 154 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 155 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 156 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 157 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 158 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 159 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 160 A.10 Flygt NP 3085 SH Technical Information BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 161 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 162 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 163 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 164 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 165 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 166 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 167 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 168 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 169 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 170 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 171 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 172 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 173 BROTHERTON DEALERSHIP TECHNICAL INFORMATION REPORT 174