Loading...
HomeMy WebLinkAboutEx08_Technical_Information_Report ENGINEERING REPORT Technical Information Report Master Site Plan Review Submittal Southport West Expansion Renton, WA PREPARED BY: COUGHLIN PORTER LUNDEEN 801 Second Avenue, Suite 900 Seattle, WA 98104 P 206.343.0460 CONTACT / Bart Balko, PE Renton, WA June 24, 2022 06/24/22EXHIBIT 8 RECEIVED Clark Close 07/15/2022 PLANNING DIVISION DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 TABLE OF CONTENTS I. PROJECT OVERVIEW .................................................................................................................................... 1 General Description .......................................................................................................................................... 1 Existing Conditions ........................................................................................................................................... 1 Proposed Drainage System .............................................................................................................................. 1 II. CONDITIONS AND REQUIREMENTS ............................................................................................................ 3 Special Requirements:...................................................................................................................................... 3 Project Specific Requirements:......................................................................................................................... 4 III. OFF-SITE ANALYSIS ..................................................................................................................................... 5 Task 1 – Study Area Definition and Maps ........................................................................................................ 5 Task 2 - Resource Review ................................................................................................................................ 5 Task 3 - Field Inspection ................................................................................................................................... 5 Task 4 - Drainage System Description and Problem Descriptions ................................................................... 5 Upstream Analysis ........................................................................................................................................ 5 Downstream Analysis .................................................................................................................................... 6 Task 5 – Mitigation of Existing or Potential Problems....................................................................................... 6 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN ....................................... 7 Existing Site Hydrology (Part A) ....................................................................................................................... 7 Developed Site Hydrology (Part B) ................................................................................................................... 7 Performance Standards and Onsite BMP’s (Parts C and D) ............................................................................ 8 Water Quality System (Part E) ........................................................................................................................ 10 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN .................................................................................. 11 Standard Requirements (based on KCSWDM and SAO): .............................................................................. 11 On-site Conveyance ....................................................................................................................................... 11 Existing Conditions: ..................................................................................................................................... 11 Developed Storm System Description: ....................................................................................................... 11 VI. SPECIAL REPORTS AND STUDIES ........................................................................................................... 13 VII. OTHER PERMITS ....................................................................................................................................... 14 VIII. CSWPPP ANALYSIS AND DESIGN .......................................................................................................... 15 Standard Requirements .................................................................................................................................. 15 ESC Analysis and Design (part A) .................................................................................................................. 16 SWPPP Plan Design (Part B) ......................................................................................................................... 16 IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT ............................... 18 X. OPERATION AND MAINTENANCE MANUAL ............................................................................................ 19 Standard Maintenance........................................................................................................................................ DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Appendix A – Figures .......................................................................................................................................... Figure 1 TIR Worksheet .................................................................................................................................. Figure 2 Site Lcoation Map ............................................................................................................................. Figure 3 USDA Soil Survey Map ..................................................................................................................... Figure 4 Sensitive Areas Map ......................................................................................................................... Figure 5 Existing Southport Conditions ........................................................................................................... Figure 6A Proposed Catchment Areas ........................................................................................................... Figure 6B Proposed Subbasin Areas .............................................................................................................. Figure 6C drainage Basin Map ....................................................................................................................... Figure 7 Proposed Southport Conditions ...................................................................................................... ` Figure 8 Water Treatment Sizing (Provided at a later date) ............................................................................ Figure 9 Flow Control Application Map ........................................................................................................... Figure 10 FEMA Firm Map .............................................................................................................................. Figure 11 Aquifer Protection Map ................................................................................................................... Figure 12 Offsite Analysis ............................................................................................................................... Appendix B– Engineering Calculations ............................................................................................................. Southport Park Avenue Conveyance Analysis ................................................................................................ Backwater Analysis ......................................................................................................................................... Water Treatment Sizing (Provided at a later date) .......................................................................................... DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 I. PROJECT OVERVIEW GENERAL DESCRIPTION The following Technical Information Report (TIR) provides the technical information and design analysis required for developing the Drainage and Temporary Erosion and Sedimentation Control Plan (TESC) for the Southport West Expansion Project Master Site Plan Review (MSPR) Permit. The stormwater design for the project was based on the requirements set forth in the 2017 Renton Surface Water Design Manual (RSWDM) (See Figure 1 – Technical Information Report Worksheet). The Southport West Expansion Project is located within the City of Renton, situated north of the existing intersection of Park Avenue and 757th Avenue. The proposed project will consist of a phased corporate office complex, separated into four phases (See Figure 2 – Site Location Map). The site is in the NW ¼ of the NW ¼ of Section 8, Township 23 North, Range 5 East, Willamette Meridian. The propose phased project is for the development of up to 1,250,000 square feet of office space within five towers on a previous Puget Sound Energy (PSE) site. Phase 1 consists of the two western most office buildings (Towers 1 and 2), and the associated western portion of the garage podium. Phase 2 will consist of two additional office buildings (Towers 3 and 4), to be constructed adjacent to Phase 1 to the east. Phase 3 will consist of Tower 5 to the east of Phase 1 and Phase 2, and phase 4 includes Tower 6 at the southwest corner of the site. The existing site consists of two parcels of mostly of gravel and asphalt with total area of 10.09 acres. The proposed conditions will include 5.77 acres of building coverage, and the remainder being road, sidewalks and pathways, with landscape and amenity areas. The existing site discharges stormwater runoff primarily to the existing Southport property to the north, into a storm conveyance system known as the “PSE Bypass” storm system. The existing PSE Bypass drainage system already accounts for portions of the Southport Hotel, portions of the existing Office lot, portions of the Southport West property, and the Park Avenue Extension. This PSE Bypass storm system has limited capacity for additional runoff volumes, with visual flooding occurring during winter rainy months. The remainder of the existing PSE properties convey runoff to John’s Creek to the east. Additionally, there is a third storm drainage system that conveys runoff between the Southport properties, and the Bristol Developments (See Figure 5 – Existing Southport Conditions). The proposed pollution generating surfaces will be captured by catch basins and treated in cartridge filter facilities prior to connection into the three existing drainage systems. Soils for the area were mapped using the King County Soil Survey maps (See Figure 3 – USDA Soil Survey Map), and results from the Geotechnical exploration will be provided as part of future permit submittals. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 EXISTING CONDITIONS The western parcel has a total area of 7.74 acres, and the eastern parcel has a total area of 2.35 acres, with a combined area of 10.09 acres. Together the existing parcels have a total impervious area of 9.66 acres, and a pervious area of 0.43 acres. The existing impervious surfaces include buildings, roadways, gravel surface area, sidewalks and concrete platforms for PSE electrical equipment. The site is currently an active PSE electrical facility, which will be relocated to a new area to the east during Phase 1 or prior to Phase 2. See Figure 7 for proposed PSE relocation vicinity. The existing drainage patterns are divided into north and south halves, with the northern areas draining to the existing PSE Bypass system and the southern areas flowing to John’s Creek. The current site is relatively flat with most of the existing area ranging from 22 feet to 25 feet. There is a gradual decline of 3 feet from the southeastern point to the northwestern region. See Table 1 for site surface cover information. The BNSF rail at the south end of the site sits at an elevation of approximately31 feet. PROPOSED DRAINAGE SYSTEM The proposed pollution generating surfaces include asphalt roadway paving, and concrete sidewalk placement. Site parking will be within underground parking garages with some parallel on-street parking stalls. The remaining site consists of building roof tops, and landscaped areas. See Table 2 for site surface cover information. According to Table 1.1.2.A of the 2017 Renton Surface Water Design Manual (RSWDM), this project meets the criteria for a Full Drainage Review, including water quality requirements. Per the 2017 RSWDM, since 100% of the runoff will directly discharge to major receiving water body (Lake Washington) Basic Water Quality measures apply. We anticipate the Full Drainage Review will take place during the construction permit process, while the intent of this report is to provide high level master plan drainage system intent for project planning. The proposed site will be distributed into three conveyance systems that each discharge directly to Lake Washington. For the purposes of this report, the three connections are referred to as the PSE Bypass, Bristol Connection, and John’s Creek. See Figure 7 for the location of these connections. The proposed drainage improvements will include the on-site and off-site conveyance improvements to the PSE Bypass system, connections to the Bristol conveyance system, as well as John’s Creek. The outfall to John’s Creek will be replaced to meet current City requirements, and to meet the site’s conveyance needs. Additionally, the project site lies within the City’s Existing Peak Flow Control basin. This project is therefore not required to provide flow control for the replaced impervious area, provided the existing downstream system has sufficient capacity to safely convey the proposed flows. The included conveyance analysis demonstrates that the Bristol and John’s Creek connections have capacity for the additional flows, and with the proposed improvements, the PSE Bypass drainage system will also have the needed capacity. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 PSE BYPASS DRAINAGE SYSTEM The proposed improvements to the PSE Bypass drainage system include upsizing the 18” line that connects the existing drainage tunnel south to Center Road. Additionally, an overflow conveyance line is being installed as part of a separate project that will resolve current capacity issues that have been reported on the current Southport Office and Hotel lots, and the current PSE site. PSE Bypass drainage system currently collects runoff generated on portions of the Southport Office Buildings, the Center Road, the Park Avenue Extension, and most of the existing PSE site, totaling 7.81 acres. The Southport West project will reduce the tributary area to the PSE Bypass line to a total of 4.73 acres to help mitigate the existing flooding issues. During Phase 1 of the Southport West project, and after the relocation of the PSE site, a temporary sediment and detention pond may be installed to help mitigate flooding issues in the interim period before the remaining phases are developed. Additionally, the existing site includes an approximate 0.50 acres which sheet flows to the adjacent Boeing property. It is likely that Phase 4 would mitigate this with the proposed Phase 4 facilities discharging into the PSE Bypass system. This is accounted for in the master plan Conveyance Analysis included in this report. BRISTOL DRAINAGE SYSTEM Portions of the proposed Towers 3 and 4 will discharge roof runoff to the Bristol Drainage System. In order to determine the available capacity of this system, the included master plan conveyance analysis evaluated the entire Bristol tributary basin. This includes portions of the Southport Hotel, Southport Office complex, the Bristol 1 and 2 developments, and portions of Southport Lane. Runoff volumes from the water quality storm event of the tributary area is conveyed to a water quality vault prior to discharging to Lake Washington. An overflow line is also available to convey excess water above the water quality storm volumes during large storm events. In order to determine the capacity of this system, it is assumed that the water quality vault is at full capacity and the overflow conveyance line is utilized. The Southport West Phase 2 will introduce 1.41 acres of roof area to this line, as well as 0.09 acres of the project frontage to Southport Lane. The conveyance analysis demonstrates that the additional tributary area introduced during Phase 2 of this project does not overload the Bristol drainage system, and the COR requirements during the 25- and 100-year storms are met. JOHN’S CREEK DRAINAGE SYSTEM The existing 12” outfall to John’s creek will be replaced with an 18” outfall. The existing connections to this outfall include a 15” line, and 12” lines. The upsizing of the outfall will help with discharging the existing tributary areas as well as the new tributary areas introduced as part of the Southport West project. The existing tributary area to this outfall at John’s Creek includes a portion of the existing PSE site, the Bristol 2 frontage, as well as a drainage swale located east of the Bristol 2 development. After the Southport West development is complete, the tributary area to this outfall will be 4.22 acres in the final condition. The conveyance analysis evaluated the entire tributary basin, which determined that the existing 12” outfall must be upsized to 18” to meet current COR conveyance requirements. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 All conveyance on site will be designed according to Chapter 4 of the 2017 Renton Surface Water Design Manual (RSWDM). The master plan calculations and system modifications demonstrate how that can be achieved. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 II. CONDITIONS AND REQUIREMENTS This section will address the requirements set forth by the Core and Special Requirements listed in Chapter 1 of the City of Renton Surface Water Design Manual. City of Renton Surface Water Design Manual Core Requirements: 1. Discharge at the Natural Location (1.2.1): This master plan project proposes to direct approximately 4.055 acres of runoff to the existing PSE Bypass drainage system, following the existing conveyance pattern. Approximately 1.496 acres are directed to the Bristol drainage system, and the remaining (approximate) 4.540 acres are directed to John’s Creek. All three conveyance methods tie into Lake Washington within a quarter mile of the site. 2. Off-site Analysis (1.2.2): Refer to Sections III and IV. A Level 1 downstream analysis has been performed, as this project will discharge to Lake Washington. 3. Flow Control (1.2.3.1): Refer to Section IV. The project is in a Peak Flow Control Area. Flow control has not been provided for the proposed improvements, due to no increase in flow during the 100-year event. The pre-development condition (total site) 100-year peak flow is 4.28 cfs, and the mitigated 100-year peak flow rate is 3.92 cfs. 4. Conveyance System (1.2.4): Refer to Section V. Closed pipe systems, treatment catch basin and extension connections have been provided for stormwater conveyance. 5. Erosion and Sedimentation Control (1.2.5): Refer to Section VIII and the demolition/TESC provided as part of this submittal. The project will construct a series of sediment controls to address the specific conditions at the site. Specific Erosion and Sedimentation Control measures will be designed as part of future permits. 6. Maintenance and Operations (1.2.6): Refer to Section X. The proposed storm drainage system will be privately owned, operated, and maintained. 7. Financial Guarantees and Liability (1.2.7): The owner and contractor will obtain all necessary permits and bonds prior to the beginning of each phase of construction. 8. Water Quality (1.2.8): Refer to Section IV. Water quality treatment for runoff from target pollution generating surfaces will be provided by cartridge filter systems. See Section IV for more information. 9. Onsite BMP (1.2.9): Refer to Section IV. Onsite BMP’s have been assessed to the maximum extent possible. Further review will be provided with each phase as part of future permits. See Section IV for more information. SPECIAL REQUIREMENTS: Special Requirement #1. Other Adopted Area-Specific Requirements Section 1.3.1 • Critical Drainage Areas (CDAs): Not Applicable • Master Drainage Plans (MDPs): There are no known master drainage plans covering this project site. • Basin Plans (BPs): The project is located within the South Lake Washington – Renton drainage basin. • Lake Management Plans (LMPs): Not Applicable • Shared Facility Drainage Plans (SFDPs): Not Applicable DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Special Requirement #2. Flood Hazard Area Delineation, Section 1.3.2: See Figure 10 for 100-yr flood zone. The site is within Zone X therefore no 100-yr flood plains have been delineated on the plans. Special Requirement #3. Flood Protection Facilities, Section 1.3.3: Not Applicable Special Requirement #4. Source Controls, Section 1.3.4: See attached Activity Worksheet and Required BMP’s. Special Requirement #5. Oil Control, Section 6.1.5. This office development site will not trigger this requirement. No oil control is required. Special Requirement #6. Aquifer Protection Area. Section 1.3.6: See attached Aquifer Protection Map under Appendix A. The site is not located in an Aquifer Protection Zone. Not applicable. PROJECT SPECIFIC REQUIREMENTS: There are no applicable project specific instructions. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 III. OFF-SITE ANALYSIS TASK 1 – STUDY AREA DEFINITION AND MAPS The Renton drainage basin map was used to verify that the site was fully in the Lake Washington South drainage basin (See Figure 6C – Drainage Basin Map). TASK 2 - RESOURCE REVIEW a) Adopted Basin Plans Lake Washington South drainage basin b) Floodplain/floodway (FEMA) Maps Site is not in the floodplain (See Figure 10) c) Off-site Analysis Reports None d) Sensitive Areas Folio No Sensitive Areas. See Figure 4 and Figure 11 e) Drainage Complaints and Studies No Drainage Complaints. See Figure 4. f) Road Drainage Problems No Current Road Drainage Problems. g) King County Soils Survey: See Figure 3 – USDA Soil Map h) Wetland Inventory Maps: No Wetlands. See Figure 4 i) Migrating Rivers Study Not Applicable. j) DOE’s Section 303d List of Polluted Waters See Section VIII, Part B of this report for Category 5 listings. k) KC Designated Water Quality Problems Not Applicable. l) City of Renton Critical Maps: See Figure 4 and Figure 11. Project is in a seismic area. TASK 3 - FIELD INSPECTION Coughlin Porter Lundeen conducted site visits in preparing the project plans. Please refer to Task 4, Downstream Analysis below for more information. TASK 4 - DRAINAGE SYSTEM DESCRIPTION AND PROBLEM DESCRIPTIONS Runoff from the site will be conveyed through new and existing storm elements that discharge to Lake Washington. The proposed site will distribute treated runoff into either the existing PSE Bypass system, the Bristol conveyance system and John’s Creek. See Appendix A, Figure 12 – Offsite Analysis Map. Upstream Analysis The site is the upstream most area for both the PSE Bypass and the Bristol conveyance systems. The site is also the upstream most area for the conveyance system that discharges into John’s Creek. The site is not the upstream most area for John’s Creek itself. See Figure 6A – Proposed Catchment Area, for reference. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Downstream Analysis As delineated in red on Figure 12 – Offsite Analysis Map, the downstream analysis begins immediately after the furthest downstream proposed pipe ties into the existing PSE Bypass system, Bristol conveyance system, and John’s Creek consisting of man-made catch basins. For the PSE Bypass system, runoff generated on the project site discharges through a system of catch basins into an underground drainage tunnel, and ultimately into Lake Washington. The distance from the PSE catch basin this project proposes to tie into to Lake Washington is approximately 750 feet, see Figure 12 for downstream conveyance route. The conveyance analysis as part of this project has identified flooding issues with the existing conveyance system, as well as noted visual minor flooding issues at the current PSE owned site, and the existing Southport Officesand Hotel. To resolve existing flooding issues, as well as to prevent flooding issues from occurring after the proposed development is complete, this project will upsize the connection up to the underground drainage tunnel. Additionally, an overflow conveyance system is being installed (not part of this project) that will parallel a portion of the underground tunnel. This was installed to resolve current flooding issues. The conveyance analysis as part of this project has determined that the existing flooding issues will be resolved with the proposed mitigation facilities and upsized conveyance system. The Southport West development will remove 1.13 acres of impervious area, with the proposed planted landscape areas. However due to existing flooding issues identified, this project proposes flood mitigation measures to minimize overtopping of existing and proposed catch basins (See Appendix B: Conveyance Analysis Calculations). City of Renton requires an elevation difference of 0.5 feet between the energy grade line and the RIM elevation for the 25-year storm, as well as limited overtopping of the conveyance system during the 100-year storm. The Conveyance Analysis calculations provided demonstrate that the proposed mitigation measures meet these requirements. TASK 5 – MITIGATION OF EXISTING OR POTENTIAL PROBLE MS The existing flooding issues mentioned previously in the report are mitigated with the proposed improvements to the downstream conveyance systems. The current flooding has been witnessed on rare occasion at the Southport Hotel loading bay area, where the existing 18” PSE Bypass line connects to the underground drainage tunnel. Visual inspection of the drainage tunnel by SECO has determined that the flooding issues are likely caused by blockage within the tunnel that constricts the runoff volume, thereby surcharging the system. An overflow 24” ductile iron pipe is currently being installed by SECO to bypass the blockage in the tunnel. Our analysis shows that this overflow pipe, along with redistributing the site tributary areas and increasing the size of the drainage pipes to the drainage tunnel along the PSE Bypass line, the flooding issues that are currently seen at the Southport Office and PSE sites would be resolved. See Conveyance Calculations, located in Appendix B: Engineering Calculations, which indicate that the system will no longer overtop the drainage system during a 100-year storm. The pipe that will connect to the existing PSE drainage tunnel will be upsized to 24-inch to mitigate these reported flooding issues. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 IV. FLOW CONTROL AND WATER QUALITY FACILITY ANALYSIS AND DESIGN EXISTING SITE HYDROLOGY (PART A) The disturbed area of 10.09 acres consists of existing asphalt and compacted gravel beyond paved areas. The PSE facility is mostly gravel, with concrete platforms for electrical equipment, and roofed facilities. Flooding has been reported within the PSE site caused by downstream conveyance issues that are detailed in this report. Due to the visual confirmation of occasional flooding, coupled with the type of existing surfaces found, it is assumed that no infiltration occurs within the site boundaries. The site slopes generally southeast to northwest, with the majority of the site flat. The site area conditions are illustrated in Figure 7 and summarized in Table 1 below. TABLE 1 - EXISTING SITE CONDITIONS AREA BREAKDOWN DESCRIPTION AREA (SQUARE FEET) AREA (ACRES) TOTAL PERVIOUS 18,790 0.43 TOTAL IMPERVIOUS 420,780 9.66 TOTAL DISTURBED AREA 420,780 9.66 DEVELOPED SITE HYDROLOGY (PART B) The existing site is almost entirely compacted gravel, paved surfaces, or building rooftop. Because of the type of surfaces documented at the site, it is assumed that little to no existing infiltration occurs. The proposed development consists of new office buildings, underground parking facilities, and open space pedestrian areas. Runoff collected from the proposed rooftops does not require treatment prior to discharging to downstream conveyance systems. Runoff from the open space pedestrian areas and proposed Frontage Road will be collected and treated by cartridge filters prior to discharging. The proposed pipe connection to the PSE Bypass system is entirely rooftop and will not require treatment. The proposed pipe connection to the Bristol drainage system is also entirely rooftop and will also not require treatment. Catch basins located on-site and along the Frontage Road will include cartridge filters that treat runoff at the basic level as described in Part E of this report. Using the rational method described in Chapter 3 of the 2017 Renton Surface Water Design Manual, the existing 100-year peak flow rate is 4.28 cfs. The proposed site reduces this 100-year peak flow rate to 3.92 cfs. These flow rates are determined for the total 10.09-acre site, and do not represent the discharge rates into the three downstream conveyance systems. See Figure 7– Proposed Conditions, for reference. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 TABLE 2 - DEVELOPED SITE CONDITIONS AREA BREAKDOWN DESCRIPTION AREA (SQUARE FEET) AREA (ACRES) TOTAL PERVIOUS 67,955 1.56 NEW IMPERVIOUS (NEW PGIS) REPLACED IMPERVIOUS (REPLACED PGIS) EXISTING IMPERVIOUS (NPGIS TO REMAIN) 0 97,655 22,540 0 2.24 0.52 TOTAL DISTURBED AREA 398,240 9.14 PERFORMANCE STANDARDS (PARTS C) According to Section 1.2.3.1 (See Figure 9 - Flow Control Application Map) of the 2017 Renton Surface Water Design Manual (RSWDM), this project is located within the Peak Flow Control area. Although this project lies within a flow control basin, the project improvements are allowed to discharge directly to Lake Washington without detention. Given that the project development satisfies all of the Direct Discharge Exemption criteria (discussed below), flow control will not be required. Direct Discharge Exemption Criteria: A) The project site discharges to Lake Washington. B) The conveyance system between the project site and the major receiving water (Lake Washington) will extend to the ordinary high-water mark and will be comprised of manmade conveyance elements (pipes) and will be within a private drainage easement. C) The conveyance system will have adequate capacity to convey the 25-year peak flow (per Core Requirement #4, Conveyance System) for the entire contributing drainage area. D) The conveyance system will be adequately stabilized to prevent erosion E) The direct discharge proposal will not divert flows from or increase flows to an existing wetland or stream sufficient to cause a significant adverse impact. To mitigate the impacts of storm and surface water runoff generated by new impervious surface onsite BMP’s were proposed. Per Section 1.2.9 of the 2017 Renton Surface Water Design Manual (RSWDM) for implementation of BMPs, an evaluation of the BMPs was done. These catch basins serve impervious area only within the proposed Southport West Development as shown per Figure 6A: Proposed Catchment Area and Figure 6B: Proposed Subbasin Area. SECO Development will assume maintenance of the cartridge filters and catch basins as they comply with the drainage facility financial guarantee and liability requirements. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 ON-SITE BEST MANAGEMENT PRACTICES (ON-SITE BMPS) PA RT D Onsite BMP’s have been assessed for this project to mitigate the impacts of storm and surface water runoff generated by new impervious surfaces, existing impervious surfaces, and replaced impervious surface targeted for mitigation. Due to direct discharge to Lake Washington, the LID performance standard does not need to be met and bioretention, permeable pavement, and full dispersion are not required to be considered. However, all other BMP’s have been assessed to the maximum extent possible per section 1.2.9 of the 2017 Renton Surface Water Design Manual (RSWDM). See assessment below. On-site BMPs Assessment SECTION REFERENCE BMP DESCRIPTION ACTION Section C.2.2 Full Infiltration Full Infiltration is infeasible because the groundwater level is relatively high in this area, estimated to be 5 feet below ground surface per the Geotechnical Analysis. Section C.2.3 Limited Infiltration Limited Infiltration is infeasible because the groundwater level is relatively high in this area, estimated to be 5 feet below ground surface per the Geotechnical Analysis. Section C.2.4 Basic Dispersion Basic Dispersion is infeasible because there is not sufficient length to install a dispersion trench, and there are no locations where a “vegetated flowpath segment” of at least 25- feet can be created. Section C.2.13 Soil Amendment Soil Amendment is feasible and will be proposed for the site. Section C.2. Perforated Pipe Perforated Pipe has been deemed infeasible for the project due to the infiltration issues described above. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 WATER QUALITY SYSTEM (PART E) Section 1.2.8.1(A) of the 2017 Renton Surface Water Design Manual (RSWDM) outlines the specific land uses within Basic Water Quality Treatment areas which are subject to providing Enhanced Basic Water Quality treatment. The project discharges to Lake Washington, a Basic Treatment Receiving Water, making it subject to Basic Water Quality treatment for all new and replaced pollution generating impervious surfaces (PGIS). This will be provided by cartridge filtration systems that are approved from the General Use Level Designation from the Washington Department of Ecology for basic treatment. The water quality cartridge filters will be installed with the proposed frontage road at each proposed catch basins. Additional cartridge filters are proposed along the frontage drainage system that discharges to the Bristol drainage system. TABLE 3. WATER QUALITY TREATMENT AREA SUMMARY NEW PGIS (REQ. TREATMENT AREA) PROPOSED TREATMENT AREA (SEE FIG 4) % DIFFERENCE 97,655 SF (1.56 AC) 97,655 SF (1.56 AC) 0% The specific treatment devices will be selected to meet required treatment flows, as well as convey all flows that will generate in a 100-year storm. Figure 8 – Water Quality Treatment Facilities will be populated in future permit submittals. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 V. CONVEYANCE SYSTEM ANALYSIS AND DESIGN This section discusses the criteria that will be used to analyze and design the proposed storm conveyance system. STANDARD REQUIREMENTS (BASED ON 2017 RSWDM AND SAO): 1. Facilities must convey the 100-year flow without overtopping the crown of the roadway, flooding buildings, and if sheet flow occurs it must pass through a drainage easement. All stormwater conveyance will be designed such that the 100-year flow is conveyed without overtopping the drive aisle or flooding any nearby buildings. 2. New pipe systems and culverts must convey the 25-year flow with at least 0.5 feet of freeboard. (1.2.4.1). The new pipe systems will be designed to convey the 25-year flow. See Conveyance Calculations under Appendix B. These new conveyance systems will meet the conveyance requirement per Section 1.2.4.1. of the 2017 RSWDM. 3. Bridges must convey the 100-year flow and provide a minimum of two feet, varying up to six feet, of clearance based on 25% of the mean channel width. (1.2.4-2)(4.3.5-6). This project does not propose a bridge. 4. Drainage ditches must convey the 25-year flow with 0.5 feet of freeboard and the 100-year flow without overtopping. (1.2.4-2). This project does not propose open channel drainage ditches. 5. Floodplain Crossings must not increase the base flood elevation by more than 0.01 feet [41(83.C)] and shall not reduce the flood storage volume [37(82.A)]. Piers shall not be constructed in the FEMA floodway. [41(83.F.1)]. No work is being proposed within the base flood elevation or within the FEMA floodway. 6. Stream Crossings shall require a bridge for class 1 streams that does not disturb or banks. For type 2 and type 3 streams, open bottom culverts or other method may be used that will not harm the stream or inhibit fish passage. [60(95.B)]. The project does not propose a stream crossing. 7. Discharge at natural location is required and must produce no significant impacts to the downstream property (1.2.1-1). The project will discharge three discharge points. The conveyance analysis as part of this report demonstrates no adverse effects to these downstream systems. ON-SITE CONVEYANCE Existing Conditions: The existing PSE site is mostly compacted gravel and is generally flat. A gradual incline in elevations is present from the northwestern edge of the site, to the southeastern. Developed Storm System Description: The project will add roughly 97,655 SF of new or replaced PGIS associated with the proposed development. These PGIS surfaces will be treated and discharged to one of three downstream conveyance systems as described in the Downstream analysis portion of Section III. (See Figure 6A – Proposed Catchment Area and DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Figure 6B – Proposed Subbasin Area). After being treated, all PGIS and NPGIS runoff from the capture area and unaffected existing Park Avenue will be conveyed through one of three downstream conveyance systems and ultimately to Lake Washington. The conveyance and backwater calculations for each of the three discharge points are provided as part of Appendix B: Engineering Calculations. The drainage basin that discharges to the drainage tunnel west of the Southport Hotel and Office developments is identified as PSE BYPASS. The drainage basin tributary to the conveyance system between the Southport Hotel and Office development and the Bristol developments is identified as BRISTOL. The final drainage basin identified as JOHN is tributary to John’s Creek. In order to determine the total effects of the flood mitigation proposals, as well as the proposed Southport West development, the entire tributary basins for each of the downstream conveyance systems is incorporated into the calculations. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 VI. SPECIAL REPORTS AND STUDIES The geotechnical report will be included in future permit submittals. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 VII. OTHER PERMITS This project will require a City of Renton Civil Construction permit, City of Renton Land Use permit, and NPDES permit. VIII. CSWPPP ANALYSIS AND DESIGN This section lists the requirements that will be used when designing the TESC plan for this site. A copy of the CSWPPP will be included prior to permit issuance for each phase. IX. BOND QUANTITY, FACILITY SUMMARIES, AND DECLARATION OF COVENANT A Bond Quantity Worksheet will be included prior to permit issuance for each phase. X. OPERATION AND MAINTENANCE MANUAL Operation and Maintenance Manual for this project will be included prior to permit issuance for each phase. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Appendix A – Figures Figures Figure 1 Technical Information Report Worksheet Figure 2 Site Location Map Figure 3 USGS Soil Map Figure 4 Sensitive Areas Map Figure 5 Existing Southport Conditions Figure 6A Proposed Catchment Area Figure 6B Proposed Subbasin Area Figure 7 Proposed Southport Conditions Figure 8 Water Treatment Sizing (Provided at a later date) Figure 9 Flow Control Application Map Figure 10 FEMA Map Figure 11 Aquifer Protection Map Figure 12 Offsite Analysis DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 CITY OF RENTON SURFACE WATER DESIGN MANUAL 2017 City of Renton Surface Water Design Manual 12/12/2016 8-A-1 REFERENCE 8-A TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND PROJECT ENGINEER Part 2 PROJECT LOCATION AND DESCRIPTION Project Owner _____________________________ Phone ___________________________________ Address __________________________________ _________________________________________ Project Engineer ___________________________ Company _________________________________ Phone ___________________________________ Project Name __________________________ CED Permit # ________________________ Location Township ________________ Range __________________ Section _________________ Site Address __________________________ _____________________________________ Part 3 TYPE OF PERMIT APPLICATION Part 4 OTHER REVIEWS AND PERMITS  Land Use (e.g., Subdivision / Short Subd.)  Building (e.g., M/F / Commercial / SFR)  Grading  Right-of-Way Use  Other _______________________  DFW HPA  COE 404  DOE Dam Safety  FEMA Floodplain  COE Wetlands  Other ________  Shoreline Management  Structural Rockery/Vault/_____  ESA Section 7 Part 5 PLAN AND REPORT INFORMATION Technical Information Report Site Improvement Plan (Engr. Plans) Type of Drainage Review (check one): Date (include revision dates): Date of Final:  Full  Targeted  Simplified  Large Project  Directed __________________ __________________ __________________ Plan Type (check one): Date (include revision dates): Date of Final:  Full  Modified  Simplified __________________ __________________ __________________ Figure 1 - TIR Worksheet SECO Development (425) 282-5833 1083 Lake Washington Blvd, Suite 50 Renton, WA 98056 Bart Balko, P.E. Coughlin Porter Lundeen (206) 343-0460 Southport West Extension 23N 5E 8 Renton, WA, 98056 5/6/2022 5/6/2022 1095 Lake Washington Blvd N DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-2 Part 6 SWDM ADJUSTMENT APPROVALS Type (circle one): Standard / Blanket Description: (include conditions in TIR Section 2) ____________________________________________________________________________________ ____________________________________________________________________________________ ____________________________________________________________________________________ Approved Adjustment No. ______________________ Date of Approval: _______________________ Part 7 MONITORING REQUIREMENTS Monitoring Required: Yes / No Start Date: _______________________ Completion Date: _______________________ Describe: _________________________________ _________________________________________ _________________________________________ Re: SWDM Adjustment No. ________________ Part 8 SITE COMMUNITY AND DRAINAGE BASIN Community Plan: ____________________________________________________________________ Special District Overlays: ______________________________________________________________ Drainage Basin: _____________________________________________________________________ Stormwater Requirements: _____________________________________________________________ Part 9 ONSITE AND ADJACENT SENSITIVE AREAS  River/Stream ________________________  Lake ______________________________  Wetlands ____________________________  Closed Depression ____________________  Floodplain ___________________________  Other _______________________________ _______________________________  Steep Slope __________________________  Erosion Hazard _______________________  Landslide Hazard ______________________  Coal Mine Hazard ______________________  Seismic Hazard _______________________  Habitat Protection ______________________  _____________________________________ Figure 1 - TIR Worksheet Lake Washington South Drainage Basin Flow control not required. No increase in impervious area. Basic WQ required. DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-3 Part 10 SOILS Soil Type ______________________ ______________________ ______________________ ______________________ Slopes ________________________ ________________________ ________________________ ________________________ Erosion Potential _________________________ _________________________ _________________________ _________________________  High Groundwater Table (within 5 feet)  Other ________________________________  Sole Source Aquifer  Seeps/Springs  Additional Sheets Attached Part 11 DRAINAGE DESIGN LIMITATIONS REFERENCE  Core 2 – Offsite Analysis_________________  Sensitive/Critical Areas__________________  SEPA________________________________  LID Infeasibility________________________  Other________________________________  _____________________________________ LIMITATION / SITE CONSTRAINT _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________ _______________________________________  Additional Sheets Attached Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Threshold Discharge Area: (name or description) Core Requirements (all 8 apply): Discharge at Natural Location Number of Natural Discharge Locations: Offsite Analysis Level: 1 / 2 / 3 dated:__________________ Flow Control (include facility summary sheet) Standard: _______________________________ or Exemption Number: ____________ On-site BMPs: _______________________________ Conveyance System Spill containment located at: _____________________________ Erosion and Sediment Control / Construction Stormwater Pollution Prevention CSWPP/CESCL/ESC Site Supervisor: _____________________ Contact Phone: _________________________ After Hours Phone: _________________________ Figure 1 - TIR Worksheet loose sandy silt Southport Park Avenue Extension Site 3 N/A TBD TBD TBD 1.2.3.1A DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-4 Part 12 TIR SUMMARY SHEET (provide one TIR Summary Sheet per Threshold Discharge Area) Maintenance and Operation Responsibility (circle one): Private / Public If Private, Maintenance Log Required: Yes / No Financial Guarantees and Liability Provided: Yes / No Water Quality (include facility summary sheet) Type (circle one): Basic / Sens. Lake / Enhanced Basic / Bog or Exemption No. _______________________ Special Requirements (as applicable): Area Specific Drainage Requirements Type: SDO / MDP / BP / Shared Fac. / None Name: ________________________ Floodplain/Floodway Delineation Type (circle one): Major / Minor / Exemption / None 100-year Base Flood Elevation (or range): _______________ Datum: Flood Protection Facilities Describe: Source Control (commercial / industrial land use) Describe land use: Describe any structural controls: Oil Control High-Use Site: Yes / No Treatment BMP: _________________________________ Maintenance Agreement: Yes / No with whom? _____________________________________ Other Drainage Structures Describe: Figure 1 - TIR Worksheet N/A Cartridge WQ catch basin utilized prior to connection to existing drainage systems. Office Building Complex, drainage modifications Cartridge Filtration Catch Basins, COR catch basins Cartridge Filteration Catch Basin designed to pass 100-yr storm peak safely DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 REFERENCE 8-A: TECHNICAL INFORMATION REPORT (TIR) WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 2017 City of Renton Surface Water Design Manual 12/12/2016 Ref 8-A-5 Part 13 EROSION AND SEDIMENT CONTROL REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION  Clearing Limits  Cover Measures  Perimeter Protection  Traffic Area Stabilization  Sediment Retention  Surface Water Collection  Dewatering Control  Dust Control  Flow Control  Control Pollutants  Protect Existing and Proposed BMPs/Facilities  Maintain Protective BMPs / Manage Project MINIMUM ESC REQUIREMENTS AFTER CONSTRUCTION  Stabilize exposed surfaces  Remove and restore Temporary ESC Facilities  Clean and remove all silt and debris, ensure operation of Permanent BMPs/Facilities, restore operation of BMPs/Facilities as necessary  Flag limits of sensitive areas and open space preservation areas  Other _______________________ Part 14 STORMWATER FACILITY DESCRIPTIONS (Note: Include Facility Summary and Sketch) Flow Control Type/Description Water Quality Type/Description  Detention  Infiltration  Regional Facility  Shared Facility  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________  Vegetated Flowpath  Wetpool  Filtration  Oil Control  Spill Control  On-site BMPs  Other ________________ ________________ ________________ ________________ ________________ ________________ ________________ Part 15 EASEMENTS/TRACTS Part 16 STRUCTURAL ANALYSIS  Drainage Easement  Covenant  Native Growth Protection Covenant  Tract  Other ____________________________  Cast in Place Vault  Retaining Wall  Rockery > 4′ High  Structural on Steep Slope  Other _______________________________ Figure 1 - TIR Worksheet Cartridge Filtration Outflow to Lake Washington DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 REFERENCE 8: PLAN REVIEW FORMS AND WORKSHEET TECHNICAL INFORMATION REPORT (TIR) WORKSHEET 12/12/2016 2017 City of Renton Surface Water Design Manual 8-A-6 Part 17 SIGNATURE OF PROFESSIONAL ENGINEER I, or a civil engineer under my supervision, have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attached Technical Information Report. To the best of my knowledge the information provided here is accurate. ____________________________________________________________________________________ Signed/Date Figure 1 - TIR Worksheet 5/6/2022 DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Figure 2 - Site Location Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 52610005261060526112052611805261240526130052613605261420559880 559940 560000 560060 560120 560180 560240 47° 30' 12'' N 122° 12' 17'' W47° 29' 56'' N 122° 12' 0'' WN Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS84 0 100 200 400 600 Feet 0 30 60 120 180 Meters Map Scale: 1:2,350 if printed on A portrait (8.5" x 11") sheet. Soil Map may not be valid at this scale. Figure 3 -USDA Soil Survey DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 36,112 3,009 City of Renton Sensitive Areas Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. 5/16/2019 Legend 2,04601,023 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 2,046 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov Erosion Hazard - High Special Flood Hazard Areas (100 year flood) Landslide Very High High Moderate Unclassified Wetlands Seismic Hazard Areas Faults Streets Parks Waterbodies Designated Neighborhoods Map Extent2010 Map Project Site Figure 4 - Sensitive Areas Map DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 LOT A LO T C NEW LOT 1CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 NEW LOT 2CITY OF RENTON LOT LINE ADJUSTMENT NO.LUA 19-000137 LO T A PAR C E L A PA R C E L A PAR C E L B PAR C E L D NEW LOT A NEW LOT A NEW LOT B75th AVE FF=33.50 GARAGE ENTRY FF=32.00 FF=35.00 FF=35.00 LOADING DOCK FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 FF=33.50 INSIDE BUILDINGTRANSFORMER LOCATED Level 1 - FF 22.0 Proposed Building Level 2 - FF 35.0 EXISTING 18" STORMWATER LINE EX WATER QUALITY VAULT BRISTOL STORM BASIN PUGET SOUND ENERGY PSE BYPASS STORM BASIN 28 8 . 0 5 f t SOUTHPORT OFFICE SOUTHPORT HOTEL BRISTOL 2 BRISTOL 1 JOHN'S CREEK STORM BASIN EXISTING 8'X8' DRAINAGE TUNNEL LAKE WASHINGTON BRISTOL DISCHARGE POINT PSE BYPASS DISCHARGE POINT (Into Drainage Tunnel) EX BRISTOL 24" OVERFLOW PIPE DRAINAGE TUNNEL DISCHARGE POINT JOHN'S CREEK DISCHARGE POINT Figure 5 - Existing Southport Conditions Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 SOUTHPORT I PSE LOT A LO T C NEW LOT 1 CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 NEW LOT 2CITY OF RENTON LOT LINE ADJUSTMENT NO.LUA 19-000137 LO T A PAR C E L A PAR C E L A PA R C E L B PAR C E L D NEW LOT A NEW LOT A NEW LOT BLO G A N A V E N 75th AVE FF=33.50 GARAGE ENTRY FF=32.00 FF=35.00 FF=35.00 LOADING DOCK FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 FF=33.50 INSIDE BUILDINGTRANSFORMER LOCATED Level 1 - FF 22.0 Proposed Building Level 2 - FF 35.0 21 3 4 5 6 78910 11 12 13 A B CD EF G H I 14 A B C DE FGHI 2 34 5 67 8 910111213 EXISTING 18" STORMWATER LINE EX WATER QUALITY VAULT PSE BYPASS STORM BASIN JOHN'S CREEK STORM BASIN EXISTING 8'X8' DRAINAGE TUNNEL LAKE WASHINGTON BRISTOL DISCHARGE POINT PSE BYPASS DISCHARGE POINT (Into Drainage Tunnel) EX BRISTOL 24" OVERFLOW PIPE DRAINAGE TUNNEL DISCHARGE POINT JOHN'S CREEK DISCHARGE POINT BRISTOL STORM BASIN PROPOSED PSE RELOCATED SITE (Drainage Pattern TBD) PUGET SOUND ENERGY SOUTHPORT OFFICE SOUTHPORT HOTEL BRISTOL 2 BRISTOL 1 Figure 6A - Proposed Catchment Area Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Figure 6B - Proposed Subbasin Area Map PSE LO T A LO T C NEW LOT 1 CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 NEW LOT 2CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 LO T A PA R C E L A PA R C E L A PA R C E L D 75th AVE GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 8910 11 12 13 A B CD EF G H I14GHI234 5 67 8 910111213 EXISTING 18" STORMWATER LINE TO BE UPSIZED TO 24" PSE BYPASS STORM BASIN JOHN'S CREEK STORM BASIN JOHN'S CREEK DISCHARGE POINT PROPOSED PSE RELOCATED SITE (Drainage Pattern TBD) BRISTOL STORM BASIN PHASE 2 DRAINAGE PATTERN TBD PHASE 1 PHASE 4 PHASE 3 South 3 (Roof): 91,000 SF Bristol 4 (Roof): 63,675 SF John 4 (Roof): 56,140 SF John 2 (Roof): 30,115 SF John 5: 20,933 SF John 6: 13,807 SF John 4: 20,696 SF John 3: 8,238 SF John 2: 16,653 SF Bristol 4: 11,328 SF South 17: 14,282 SF South 14: 3,005 SF South 13: 2,508 SF South 12: 3,073 SF DRAINAGE PATTERN TBD South 11: 3,889 SF South 10: 5,966 SF South 9: 7,737 SF South 8: 4,865 SF South 7: 2,270 SF South 6: 1,413 SF South 5: 2,522 SF South 4: 4,769 SF Southport West Expansion C200194-16 May 2022 DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 72,224 6,019 City of Renton Drainage Basin Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. 5/15/2019 Legend 4,09302,046 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 4,093 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Drainage Sub Basins <all other values> Black River Boren Creek Cabbage Creek Cedar Grove Cedar Main Urban China Creek Country Creek Duamish East Fork May Creek Garrison Creek Ginger Creek Greenes Creek Gypsy Honey Creek Jenkins Creek Main Lake Kathleen Lake Washington - East Lake Washington - West Johns Creek Lake Washington South Little Soos Creek Long Marsh Creek Lower May Creek Project Site Figure 6C - Drainage Basin Map DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 SOUTHPORT I PSE LOT A LO T C NEW LOT 1 CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 NEW LOT 2CITY OF RENTON LOT LINE ADJUSTMENT NO.LUA 19-000137 LOT A PA R C E L A PAR C E L A PAR C E L B PAR C E L D NEW LOT A NEW LOT A NEW LOT B75th AVE FF=33.50 GARAGE ENTRY FF=32.00 FF=35.00 FF=35.00 LOADING DOCK FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 FF=33.50 INSIDE BUILDINGTRANSFORMER LOCATED Level 1 - FF 22.0 Proposed Building Level 2 - FF 35.0 21 3 4 5 6 78910 11 12 13 A B CD EF G H I 14 A B C DE FGHI2 34 5 67 8 910111213 EXISTING 18" STORMWATER LINE EX WATER QUALITY VAULT EXISTING 8'X8' DRAINAGE TUNNEL LAKE WASHINGTON BRISTOL DISCHARGE POINT PSE BYPASS DISCHARGE POINT (Into Drainage Tunnel) EX BRISTOL 24" OVERFLOW PIPE DRAINAGE TUNNEL DISCHARGE POINT JOHN'S CREEK DISCHARGE POINT PROPOSED PSE RELOCATED SITE (Drainage Pattern TBD) SOUTHPORT WESTEXPANSION SOUTHPORT OFFICE SOUTHPORT HOTEL BRISTOL 2 BRISTOL 1 PSE BYPASS DRAINAGE SYSTEM BRISTOL DRAINAGE SYSTEM JOHN'S CREEK DRAINAGE SYSTEM Figure 7 - Proposed Southport Conditions Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 LakeDesire ShadyLake (MudLake) PantherLake LakeYoungs LakeWashington Bl a c kRi ver Gr eenRiv e r C edarRi verUV900 UV167 UV515 UV169 UV900 UV169 UV167BN IncBN IncBBNNIInnccSSEERReennttoonn II ssss aa qquuaahh RR dd RReennttoonnMMaappllee VVaalllleeyyRRdd MMaapplleeVVaalllleeyyHHwwyy 110088tthhAAvveeSSEESSWW SSuunnsseettBBllvvdd RRaaiinnii eerrAAvveeNNNE 3rd StNE 3rd St SW 43rd StSW 43rd St SS EE CCaarrrrRR dd NE 4th StNE 4th St SSEE RReennttoonn MMaappllee VVaalllleeyy RRddLLooggaannAAvveeNN SR 515SR 515PPaarrkkAAvveeNNOOaakkeessddaalleeAAvveeSSWWSSuunnsseettBBllvvddNN EE DDuuvvaallllAAvveeNNEEI-405 FWYI-405 FWY II--440055FFWWYYSR 167SR 167114400tthh WWaayySS EENNEE 2277tthh SStt 115566tthhAAvveeSSEEUUnniioonnAAvveeNNEE111166tthhAAvveeSSEESW 7th StSW 7th St N 8th StN 8th St PP uuggeettDDrrSSEE RR ee nnttoonnAAvvee SS SSWW 2277tthh SStt BBeennssoonnRRddSSWWiilllliiaammssAAvveeSSMMoonnrrooeeAAvveeNNEESE 128th StSE 128th St II nntt eerr uurr bbaannAAvveeSS HHooqquuiiaammAAvveeNNEE8844tthhAAvveeSSSSEEPPeett rr oovvii tt sskkyyRRddEEVVaalllleeyyHHwwyySE 192nd StSE 192nd St SE 60th StSE 60th St TTaallbboottRRddSSRRee nn tt oo nn AAvveeSS116644tthhAAvveeSSEESE 208th StSE 208th St SE 72nd StSE 72nd St RRaaiinniieerr AAvvee SS 111166tthhAAvveeSSEES 128th StS 128th St NNeewwccaassttllee WWaayy SS 221122tthh SStt SS 118800tthh SStt CCooaall CCrreeeekkPPkkwwyySSEESW 41st StSW 41st St 114400tthhAAvveeSSEE112288tthhAAvveeSSEE6688tthhAAvveeSSSSEE 116688tthh SStt NE 12th StNE 12th St BBee aa ccoonn AA vv ee SS FFoorreesstt DDrr SSEE SSEE 116644tthh SStt 114488tthhAAvveeSSEESSEE MMaayy VVaalllleeyy RRdd SS EE JJ oo nn ee ss RR dd SSEE 22 00 44 tthh WW aayySW 34th StSW 34th St SE 144th StSE 144th St 114488tthhAAvveeSSEE115544tthhPPllSSEELL aa kk ee WWaa sshhii nnggtt oonnBBll vvddNNEEddmmoonnddssAAvveeNNEEAAbbeerrddeeeennAAvveeNNEEEEMM eerrcceerrWWaayyWWeessttVVaalllleeyyHHwwyyEast Valley RdEast Valley Rd,§-405 ,§-405 ,§-405 µ0 1 2Miles Flow Control Application Map Reference 15-A Date: 01/09/2014 Flow Control Standards Peak Rate Flow Control Standard (Existing Site Conditions) Flow Control Duration Standard (Existing Site Conditions) Flow Control Duration Standard (Forested Conditions) Flood Problem Flow Unincorporated King County Flow Control Standards Renton City Limits Potential Annexation Area Figure 9 - Flow Control Application Map Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Figure 10 - FEMA Flood Insurance Rate Map (FIRM) Southport West Expansion Site (Approximate) DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 k k k k k k k k k k k k k k k k k k k k k k k k k k k kk k k k k k k k k k k k k k k k k k k k HoquiamAveNEE Valley Hwy84thAveSNEParkD r SW 7th St SE 128th St SE 192nd StLind Ave SWMainAveSS 132nd St Factory PlN Talbot Rd SN 3rd St RainierAveS 164thAveSETukwila Pk w y SPuget Dr NE 4th St S 3rd St S 1 2 9 thS t68thAveSSWSunsetBlvd SW 16th St 116thAveSEN 4th St I n t e r u r b a n Av e S WilliamsAveNBronsonW a y N NE7thSt 124thAveSES 7th St SERenton IssaquahRd Rai ni er AveNNewcastle Way CoalCr e e k PkwySESW 41st St T a y l o r P l NW NESunsetBlvdWellsAveNUnionAveNENE 3rd St Ha r die A v eSWS180th St Maple V a l l e y H w y 140thAveSES G radyWayS 2 1 s tSt BensonRdSRe nt o n AveS87thAveS128thAveSE148thAveSESW 43rd St SEC arrR d SE 168th St Beaco n A v e S 68thAveSLoganAveN108thAveSEForestDr SE S2ndSt 141 s tAve S ERainierAveS 156thAveSES E 183rd StBenson D r S S 124th StS 43rd St Airport Way S W G radyW a y S E J o n e s RdSunsetBlvdN Puget Dr SESE 204th Way SW 34th StMo n s ter RdSW SE 142nd Pl WestValleyHwySSEMay ValleyRd SunsetBlvdNS C a r r RdHouserWayNNewcastle GolfClubRd S 133rd St WilliamsAveSWellsAveSEMercerWay154thPlSEDuvallAveNELoganAveSMonroeAveNESunsetBlvdNEEdmondsAveNEStevens AveNWRai ni er AveSTalbotRdSOakesdaleAveSWTaylorAveNW164thAveSERainierAveSWestVal leyHwyWestValleyHwyParkAveN108thAveSE6 6 t h Av e SWMercerWayWMercer W ay Lakemont BlvdSE132ndAve SELakeWashingtonBlvdNE140thWaySE East Valley Rd68thAveS³City of RentonSensitive Areas 0 0.5 10.25 Miles Information Technology - GISmapsupport@rentonwa.govPrinted on: 11/12/2014 Data Sources: City of Renton, King County This document is a graphic representation, not guaranteedto survey accuracy, and is based on the best informationavailable as of the date shown. This map is intended forCity display purposes only. Renton City Limits k Education Fire Station K Valley Medical Center Aquifer Protection Zone 1 Zone 1 Modified Zone 2 Coordinate System: NAD 1983 HARN StatePlane Washington North FIPS 4601 FeetProjection: Lambert Conformal ConicDatum: North American 1983 HARN Figure 11 - Aquifer Protection Map Project Site DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 9,028 752 Figure 11 - Offsite Analysis Map This map is a user generated static output from an Internet mapping site and is for reference only. Data layers that appear on this map may or may not be accurate, current, or otherwise reliable. None 5/20/2019 Legend 5120256 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere Information Technology - GIS RentonMapSupport@Rentonwa.gov City and County Boundary Parcels Water Gravity Pipes Water Mains Mains - Other System Water Service Areas Lift Stations Pressurized Mains Renton Private Gravity Mains Renton Private Wastewater Service Areas KC Pressurized Mains KC Gravity Mains Pump Stations Discharge Points Stormwater Mains Culverts Open Drains Facility Outlines Private Pump Stations Private Discharge Points Private Pipes Private Culverts EXISTING PSE DRAINAGE SYSTEM ROUTE Project Site CONNECTION TO EXISTING PSE DRAINAGE SYSTEM Figure 12 -Offsite Analysis Map John's Creek CONNECTION TO EXISTING BRISTOL DRAINAGE SYSTEM CONNECTION TO EXISTING JOHN'S CREEK DRAINAGE SYSTEM DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Appendix B – Engineering Calculations SOUTHPORT WEST CONVEYANCE ANALYSIS BACKWATER ANALYSIS WATER TREATMENT SIZING (WWHM) (To be included prior to permit issuance) DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 SOUTHPORT I PSE LOT A LO T C NEW LOT 1 CITY OF RENTON LOT LINE ADJUSTMENT NO. LUA 19-000137 NEW LOT 2CITY OF RENTON LOT LINE ADJUSTMENT NO.LUA 19-000137 LOT A PA R C E L A PAR C E L A PAR C E L B PAR C E L D NEW LOT A NEW LOT A NEW LOT B75th AVE FF=33.50 GARAGE ENTRY FF=32.00 FF=35.00 FF=35.00 LOADING DOCK FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 GARAGE ENTRY FF=22.00 FF=33.50 INSIDE BUILDINGTRANSFORMER LOCATED Level 1 - FF 22.0 Proposed Building Level 2 - FF 35.0 21 3 4 5 6 78910 11 12 13 A B CD EF G H I 14 A B C DE FGHI2 34 5 67 8 910111213 EXISTING 18" STORMWATER LINE EX WATER QUALITY VAULT EXISTING 8'X8' DRAINAGE TUNNEL LAKE WASHINGTON BRISTOL DISCHARGE POINT PSE BYPASS DISCHARGE POINT (Into Drainage Tunnel) EX BRISTOL 24" OVERFLOW PIPE DRAINAGE TUNNEL DISCHARGE POINT JOHN'S CREEK DISCHARGE POINT PROPOSED PSE RELOCATED SITE (Drainage Pattern TBD) SOUTHPORT WESTEXPANSION SOUTHPORT OFFICE SOUTHPORT HOTEL BRISTOL 2 BRISTOL 1 PSE BYPASS DRAINAGE SYSTEM BRISTOL DRAINAGE SYSTEM JOHN'S CREEK DRAINAGE SYSTEM Appendix B.1 -Conveyance Profile Map PROFILE C (John's Creek) PROFILE B (Bristol Drainage System) PROFILE A (PSE Bypass Drainage System) DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.2 - Conveyance Calculations Total Roof Pave/ Conc Pervious Tc (min) Manning's Coefficient 2-year,24 hr (in) S (ft/ft) Sheet Flow Length (ft) All Total 865,277 560,290 271,263 33,724 South 1 South 2 45,965 45,965 9.27 0.014 0.2 0.04 250 South 3 91,000 91,000 11.86 0.014 0.2 0.04 340 South 4 4,769 4,316 453 6.30 0.014 0.2 0.04 South 5 2,522 2,522 6.30 0.014 0.2 0.04 South 6 1,413 1,413 6.30 0.014 0.2 0.04 South 7 2,270 2,040 230 6.30 0.014 0.2 0.04 South 8 4,865 4,600 265 6.30 0.014 0.2 0.04 South 9 7,737 4,173 3,564 6.30 0.014 0.2 0.04 South 10 5,966 3,699 2,267 6.30 0.014 0.2 0.04 South 11 3,889 3,731 158 6.30 0.014 0.2 0.04 South 12 15,663 12,590 2,884 189 6.30 0.014 0.2 0.04 152 South 13 2,508 2,363 145 6.30 0.014 0.2 0.04 South 14 3,005 3,005 6.30 0.014 0.2 0.04 South 15 6.30 0.014 0.2 0.04 South 16 6.30 0.014 0.2 0.04 South 17 14282 13939 343 6.30 0.014 0.2 0.04 South Total 205,854 149555 48685 7614 John 1 17086 11563 5523 John 2 46768 30115 13233 3420 7.82 0.014 0.2 0.04 202 John 3 8238 8238 6.30 0.014 0.2 0.04 John 4 76836 56140 15740 4956 9.27 0.014 0.2 0.04 250 John 5 20933 19882 1051 6.30 0.014 0.2 0.04 John 6 13807 12482 1325 6.30 0.014 0.2 0.04 John Total 183668 86255 81138 16275 Bristol 1 171,994 103,418 66,856 1,720 11.89 0.014 0.2 0.04 341 Bristol 2 72,402 63,675 3,500 5,227 12.73 0.025 0.2 0.04 208 Bristol 3 118,018 95,812 21,906 300 10.73 0.014 0.2 0.04 300 Bristol 4 113,341 61,575 49,178 2,588 8.67 0.014 0.2 0.04 230 Bristol Total 475755 324480 141440 9835 Notes: Time of Concentration is estimated for sheet flow concentrations. Time of concentration for flow within channels, and pipes is done within SSA Manning's Roughness Coefficient for roof areas are estiamated to be 0.014 The slope of roofs are estimated to be 2% (typical) The 2 year, 24 hour storm rainfall depth was determined from the NOAA Atlas 2, Volume 9 DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.3 - Profile A -25 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.4 - Profile A -100 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.5 - Profile B -25 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.6 - Profile B -100 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.7 - Profile C -25 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433 Southport West Expansion C200194-16 May 2022 Appendix B.8 - Profile C -100 Year, 24 Hour Storm DocuSign Envelope ID: 6EA7C613-A4CD-406B-935E-3399EFC72433