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Home My WebLink AboutRS_TIR Drainage Report_Apron E _200122_v2.pdf Technical Information Report for Boeing Commercial Airplanes Apron E Stalls and Paint Hangar Prepared for: Boeing Commercial Airplanes, Seattle District P.O. Box 3707, M/S: 1W-10 Seattle, Washington 98124 Prepared by: 8410 154th Avenue NE, Suite 120 Redmond, WA 98052 Tele: (425) 869-2670 FAX: (425) 869-2679 90% Design Submittal December 2019 This report has been prepared by the staff of DOWL under the direction of the undersigned professional engineer whose stamp and signature appears hereon. 13726.16 Table of Contents 1.0 PROJECT OVERVIEW .................................................................................................................... 5 Figure 1: TIR Worksheet ......................................................................................................................................... 6 Figure 2: Vicinity Map .......................................................................................................................................... 11 Figure 3: Drainage Basin Map .............................................................................................................................. 12 Figure 4: Soils Mapping ........................................................................................................................................ 13 2.0 CONDITIONS & REQUIREMENTS SUMMARY ................................................................. 16 3.0 OFF-SITE ANALYSIS .................................................................................................................... 19 3.1 Define and Map the Study Area .................................................................................................................. 19 3.2 Review All Available Information On the Study Area .................................................................................. 19 3.3 Field Inspect the Study Area ....................................................................................................................... 19 3.4 Describe the Drainage System .................................................................................................................... 19 Figure 5: Downstream Flow Path to Lake Washington ......................................................................................... 20 Figure 6: Flood Map ............................................................................................................................................. 21 Figure 7: Critical Areas Map ................................................................................................................................. 22 4.0 FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS & DESIGN ................................ 23 4.1 Existing Site Hydrology ............................................................................................................................... 23 4.2 Developed Site Hydrology .......................................................................................................................... 24 4.3 Flow Control ............................................................................................................................................... 24 4.4 On-Site Flow Control BMPS ........................................................................................................................ 24 4.5 Water Quality ............................................................................................................................................. 25 Figure 8: Existing Conditions ................................................................................................................................ 27 Figure 9: Proposed Conditions ............................................................................................................................. 28 5.0 CONVEYANCE SYSTEM ANALYSIS & DESIGN ......................................................................... 29 6.0 SPECIAL REPORTS & STUDIES .................................................................................................. 30 7.0 OTHER PERMITS ......................................................................................................................... 31 8.0 CWSPPP ANALYSIS AND DESIGN ............................................................................................. 32 8.1 Erosion and Sediment Control (ESC) Measures ........................................................................................... 32 8.1.1 Clearing Limits .......................................................................................................................................... 32 8.1.2 Cover Measures ........................................................................................................................................ 32 8.1.3 Perimeter Protection ................................................................................................................................ 32 8.1.4 Traffic Area Stabilization ........................................................................................................................... 32 8.1.5 Sediment Retention .................................................................................................................................. 32 8.1.6 Surface Water Collection .......................................................................................................................... 32 8.1.7 Dewatering Control .................................................................................................................................. 32 8.1.8 Dust Control .............................................................................................................................................. 33 8.1.9 Flow Control ............................................................................................................................................. 33 8.1.10 Control Pollutants ................................................................................................................................ 33 8.1.11 Protect Existing and Proposed Flow Control BMPS ............................................................................. 33 8.1.12 Maintain BMPs ..................................................................................................................................... 33 8.1.13 Manage the Project ............................................................................................................................. 33 8.2 SWPPS Measures ........................................................................................................................................ 33 8.2.1 Pollutant Handling and Disposal ............................................................................................................... 33 8.2.2 Cover and Containment for Materials, Fuel and Other Pollutants ........................................................... 34 8.2.3 Manage the Project Site ........................................................................................................................... 34 8.2.4 Protect from Spills and Drips .................................................................................................................... 34 8.2.5 Avoid Overapplication or Untimely Application of Chemicals and Fertilizers .......................................... 34 8.2.6 Prevent or Treat Contamination of Stormwater Runoff ........................................................................... 34 8.3 SWPPP Plan Design ..................................................................................................................................... 34 8.3.1 Element 1 – Preserve Vegetation / Mark Clearing Limits ......................................................................... 34 8.3.2 Element 2 – Establish Construction Access .............................................................................................. 35 8.3.3 Element 3 – Control Flow Rates ............................................................................................................... 35 8.3.4 Element 4 – Install Sediment Controls ..................................................................................................... 35 8.3.5 Element 5 – Stabilize Soils ........................................................................................................................ 35 8.3.6 Element 6 – Protect Slopes ....................................................................................................................... 35 8.3.7 Element 7 – Protect Drain Inlets ............................................................................................................... 35 8.3.8 Element 8 – Stabilize Channels and Outlets ............................................................................................. 35 8.3.9 Element 9 – Control Pollutants ................................................................................................................. 35 8.3.10 Element 10 – Control Dewatering ....................................................................................................... 36 8.3.11 Element 11 – Maintain BMPs............................................................................................................... 36 8.3.12 Element 12 – Manage the Project ....................................................................................................... 36 8.3.13 Element 13 – Protect Low Impact Development (LID)......................................................................... 36 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT .......... 37 9.1 Bond Quantities .......................................................................................................................................... 37 9.2 Flow Control and Water Quality Facility Summary Sheet and Sketch.......................................................... 37 9.3 Declaration of Covenant for Privately Maintained Flow Control and Water Quality Facilities .................... 37 10.0 OPERATIONS & MAINTENANCE MANUAL ............................................................................. 38 Appendix A SWPPP Plans Appendix B WWHM Report Appendix C Water Quality Treatment Standard Detail Appendix D Conveyance and Backwater Analysis Calculations Appendix D.1 25 Year Conveyance Calculations Appendix D.2 100 Year Lake Washington Backwater Analysis Appendix D.3 100 Year North System Backwater Analysis Appendix D.4 100 Year South System Backwater Analysis Appendix E Stormwater Drainage Plans and Details Appendix F City of Renton Bond Quantity Worksheet Appendix G Draft Geotechnical Investigation by S&EE Appendix H Flow Splitter Calculations 5 1.0 PROJECT OVERVIEW This Technical Information Report is submitted to the City of Renton in support of the Apron E Expansion Project on the existing parking lot proposed by Boeing. The project proposes to construct three airplane stalls and a paint hangar on the existing parking lot. The Apron E Expansion Project area is located at the intersection of Logan Ave N and N 6th St, adjacent to the Apron D project site. The existing parking lot is situated between the Apron D project area and Logan Ave N. The northern boundary of the lot is adjacent to N 6th St. The project will use the 2017 Renton Surface Water Design Manual (RSWDM). The project is required to undergo a Full Drainage Review in accordance with Figure 1.1.2.A of the RSWDM since it will be removing or replacing over 2,000 square feet of impervious surface. The project is located on the east side of the Cedar River, which flows north towards Lake Washington. The project area will discharge directly into Lake Washington. For this project threshold discharge area (TDA 1), flow control is not required since the proposed system connects into an existing system that is considered to be exempt from flow control. The project will provide enhanced water quality treatment by implementing MWS-Linear Modular Wetland structures upstream of the discharge point. The projects consists of urban land per the USDA soil map. According to the geotechnical report, Information Provided: Figure 1: TIR Worksheet Figure 2: Vicinity Map Figure 3: Drainage Basin Map Figure 4: Soils Mapping 6 Figure 1: TIR Worksheet 11 Figure 2: Vicinity Map APRON E - STALLS PHASE 1 PROJECT VICINITY MAP WWW.DOWL.COM FIGURE 2 PROJECT SITE 12 Figure 3: Drainage Basin Map BOEING 737-MAX10BOEING 737-MAX10GV 1 APRON E - STALLS PHASE 1 DRAINAGE BASIN MAP WWW.DOWL.COM 1 FIGURE 3 13 Figure 4: Soils Mapping 16 2.0 CONDITIONS & REQUIREMENTS SUMMARY Existing Conditions The Apron E Expansion project area is located at the intersection of Logan Ave N and N 6th St, adjacent to the Apron D project site. The existing parking lot is situated between the Apron D project area and Logan Ave N. The northern boundary of the lot is adjacent to N 6th St. The existing project area is currently being uses as a parking lot with existing utilities in place. The existing parking lot is a mix of old concrete and asphalt pavement along with existing lighting and drainage structures. The storm system currently discharges to the existing storm system located in Apron D just west of the project site. The existing onsite storm system will be removed and replaced with the proposed storm drain system that will collect and convey runoff from the new apron facilities. The new storm lines will tie into the existing storm system. The existing system discharges to a storm drain interceptor pipe system which runs north, parallel with the Cedar River and eventually discharges into Lake Washington. The project site is gently sloped and surfaced primarily with concrete and asphalt pavement, with minimal grass landscaping. Site soils are classified as a mix of compacted pitrun (mix of sand and gravel), silt, silty sand, and thick layer of sand and gravel. The site soils are obtained from the draft geotechnical investigation from S&EE in Appendix G. Figure 3 is a soil map from the USDA Web Soil Survey. Full Drainage Review This project includes more than 2,000 square feet of new and replaced impervious surface. Therefore, the project is subject to a full drainage review and must satisfy all 9 Core Requirements and 6 Special Requirements of the RSWDM. The following summary describes how this project will meet the “Core Requirements” and “Special Requirements” that apply according to Section 1.2 in the RSWDM. RSWDM Core Requirements 1. Core Requirement #1: Discharge at the Natural Location The project area will continue to discharge into the existing storm system within Apron D but will modify the on-site storm system in order to convey runoff to the discharge point. The project area can be considered to be one TDA since all runoff from the site converges at a single discharge point. 2. Core Requirement #2: Off-Site Analysis See Section 3.0 for a detailed discussion on off-site analysis. The project is required to provide a Level 1 downstream analysis as described in Section 1.2.2.1 of the RSWDM. 17 3. Core Requirement #3: Flow Control See Section 4.0 for a detailed discussion on flow control facilities for the project. The project is exempt from the flow control provisions since the proposed storm system connects into an existing system that discharges into a flow control exempt waterbody. 4. Core Requirement #4: Conveyance System Under this core requirement, new pipe systems must be analyzed for capacity to contain and convey at minimum the 25-year peak flow. The proposed drainage system will be sized to convey and contain the 25-year peak flow. See Section 5.0 for a detailed discussion on conveyance. 5. Core Requirement #5: Erosion & Sediment Control Temporary erosion and sediment control will be provided for the project. A Temporary Erosion and Sediment Control Plan (TESC) has been prepared and included in the plan set. CSWPP is covered under Section 8.0 of this report. A full CSWPP report can be found in Appendix A. 6. Core Requirement #6: Maintenance and Operations See Section 10.0 of this report for a detailed discussion on maintenance and operations. Ownership of the existing stormwater system (Boeing Renton) will not change and the current maintenance program will remain in place. The site is staffed 24-hours a day, there is a central monitoring system in place providing for timely notification of problems. 7. Core Requirement #7: Financial Guarantees and Liability The project will comply with financial guarantees as required by the City of Renton. 8. Core Requirement #8: Water Quality The project area is above the 5,000 square foot threshold for providing water quality treatment. The project location is considered an industrial site. Therefore, Enhanced Basic Water Quality is required per Section 1.2.8.1 of the RSWDM. The project will implement MWS-Linear Modular Wetland structures upstream of the discharge point. 9. Core Requirement #9: On-Site BMPS The project is required to apply on-site flow control BMPs to new impervious surfaces. See Section 4.0 for a detailed discussion regarding on-site flow control BMPs. City of Renton Special Requirements 1. Special Requirement #1: Other Adopted Area-Specific Requirements The site is not located within an area having specific requirements above and beyond the core requirements. 2. Special Requirement #2: Flood Hazard Area Delineation The project site is not within the 100- year floodplain. This project is located Zone X Other Flood Areas, 500-year floodplain per the City of Renton (COR) mapping. See Figure 5. 18 3. Special Requirement #3: Flood Protection Facilities This project does not propose to rely on an existing flood protection facility nor does it modify or construct a new flood protection facility. 4. Special Requirement #4: Source Control This project does warrant source controls. Fuel spill control and containment will be provided for those areas that might hold a fueled or previously fueled aircraft. 5. Special Requirement #5: Oil Control For a redevelopment project, where the threshold of new plus replaced pollution generating impervious surfaces of 5,000 square feet is exceeded, runoff treatment is required. The project will implement two Baffle Oil-Water Separator structures upstream of the discharge point. 6. Special Requirement #6: Aquifer Protection Area The project is not located in an Aquifer Protection Area Zone per City of Renton Groundwater Protection Areas (printed 11/12/2014) provided in the City of Renton Surface Water Design Manual (SWDM) Special Requirements. 19 3.0 OFF-SITE ANALYSIS Per RSWDM 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 improvements to the project site. The project requires a Level 1 downstream analysis as described in Section 1.2.2.1 of the RSWDM. 3.1 Define and Map the Study Area The project site has a single discharge point to the west of the project site, which connects into the existing storm system in Apron D. The project will maintain the existing discharge point. See Figure 4 for the downstream flow path map. 3.2 Review All Available Information On the Study Area City of Renton mapping and data were reviewed. There are no drainage complaints listed within ¼ mile of the project site. The Department of Ecology 303d listings were reviewed for Lake Washington. Some of the listings include Bacteria and Total Phosphorus. The USDA soils map identifies the on-site soils as Urban land. 3.3 Field Inspect the Study Area The downstream flow path from the single discharge point was inspected using the City of Renton GIS Map. No field inspections were completed for this project. There is no evidence of existing drainage and water quality problems at the project site or downstream of the discharge points. The project area discharges into the existing storm system in Apron D, just west of the project site. The existing system conveys flow to a storm drain interceptor pipe system which runs north, parallel with the Cedar River. The interceptor begins as a 24-inch diameter pipe which gradually upsizes to a 60-inch diameter pipe as flow travels north. The pipe system discharges directly into Lake Washington. 3.4 Describe the Drainage System There is no evidence of existing drainage and water quality problems at the project site or downstream of the discharge points. The project will not implement any flow control facilities for the proposed improvements. There are no predicted or anticipated drainage problems at the project site. 20 Figure 5: Downstream Flow Path to Lake Washington Downstream Analysis Map 1000 ft N➤➤N © 2018 Google © 2018 Google © 2018 Google 21 Figure 6: Flood Map 9,028 752 City of Renton Flood 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. 6/18/2019 Legend 5120 256 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere City and County Labels 22 Figure 7: Critical Areas Map 9,028 752 City of Renton Critical 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. 5/22/2019 Legend 5120 256 THIS MAP IS NOT TO BE USED FOR NAVIGATION Feet Notes 512 WGS_1984_Web_Mercator_Auxiliary_Sphere City and County Boundary Parcels Erosion Hazard - High Floodway Special Flood Hazard Areas (100 year flood) Seismic Hazard Areas Faults Streets Parks Waterbodies Map Extent2010 23 4.0 FLOW CONTROL & WATER QUALITY FACILITY ANALYSIS & DESIGN 4.1 Existing Site Hydrology The existing project site is currently being used as a parking lot with the ground cover being almost all impervious surface. The existing parking lot is a mix of old concrete and asphalt pavement along with existing lighting, buried utilities, and drainage structures. The project site is gently sloped, with minimal grass landscaping on-site. See Figure 8 for an existing conditions map. The project area can be considered to be one TDA since all runoff from the site converges at a single discharge point. The storm system currently discharges to the existing storm system located in Apron D just west of the project site. The existing system discharges to a storm drain interceptor pipe system which runs north, parallel with the Cedar River and eventually discharges into Lake Washington. The total area of the TDA is 9.82 acres. See Table 1 for the summary of areas in the existing conditions. Table 1: Existing Site Area Summary Existing Impervious Surface 384,380 SF 8.82 Acres Existing Pervious Surface 43,553 SF 1.00 Acres Total 427,933 SF 9.82 Acres 24 4.2 Developed Site Hydrology The Apron E Expansion project proposes to construct three airplane stalls and a paint hangar on the existing parking lot. The project proposes to convey all stormwater facilities to the existing storm system located in Apron D. The project will continue to discharge into the existing storm system within Apron D but will modify the on-site storm system in order to convey runoff to the discharge point. In the developed condition, the project area is still one TDA since all stormwater runoff from the site converges at a single discharge point. The proposed storm system will convey flow to the existing storm system in Apron D, which connects to a storm drain interceptor pipe system that runs north, parallel with the Cedar River and discharges into Lake Washington. Flow control facilities will not be implemented on- site. The project area in the developed condition will match the existing conditions with impervious surface covering the majority of the site. The surface will consist primarily of replaced impervious surfaces, along with some new impervious and landscape areas. See Table 2 for the summary of areas in the developed condition. Table 2: Developed Site Area Summary New Impervious Surface 30,822 SF 0.70 Acres Replaced Impervious Surface 365,772 SF 8.40 Acres New Pervious Surface 31,339 SF 0.72 Acres Total 427,933 SF 9.82 Acres 4.3 Flow Control The project area is currently tributary to the existing storm system in Apron D. The project will continue to discharge into the existing storm system within Apron D but will modify the on-site storm system in order to convey runoff to the discharge point. The existing storm system directly discharges into Lake Washington, which is considered a flow control exempt waterbody. The project will match existing conditions and connect into the existing system that discharges out to Lake Washington. Flow control facilities will not be implemented on-site. Additionally, the project threshold discharge area (TDA) does not generate more than a 0.15 cfs increase in the developed condition when modeled using 15 minute time steps in WWHM. The 100-year peak flow rates for the predeveloped and developed condition are 7.08 and 7.22 cfs, respectively, which results in a difference of 0.14 cfs. According to Section 1.2.3 of the RSWDM, the project area is exempt from flow control requirements since the proposed development only results in an increase of 0.14 cfs. See Appendix B for the report generated in WWHM. 4.4 On-Site Flow Control BMPS Per Core Requirement #9 of the RSWDM, the project is required to apply on-site flow control BMPs. According to Core Requirement #9 of the RSWDM, projects qualifying as exempt from flow control facility requirement using the Direct Discharge Exemption are not required to achieve the LID performance 25 requirement using the Direct Discharge Exemption are not required to achieve the LID performance standard, or consider bioretention, permeable pavement, and full dispersion. Below are the BMPs considered for on-site flow control for the target pervious and impervious surfaces per the RSWDM: Target Pervious Surfaces – Pervious surfaces will be protected in accordance with the Soil Amendment BMP as detailed in Appendix C, Section C.2.13 of the RSWDM. Target Impervious Surfaces • Full Infiltration (Appendix C, Section C2.2 of the RSWDM) – Full Infiltration is not feasible due to the lack of pervious landcover and the existing underlying soil. The geotechnical report states that the existing soils are comprised of fill materials and do not meet the required criteria for Full Infiltration. • Basic Dispersion (Appendix C, Section C2.4 of the RSWDM) – Basic Dispersion is not feasible due to the lack of pervious surfaces on site. There is no vegetated flow path for the stormwater runoff on site. Roofs • Perforated Pipe Connection for Roofs (Appendix C, Section C2.11) – Perforated pipe connections for roofs are not feasible due to the lack of pervious landcover. The gravel filled trench cannot be constructed on-site since the project area is mostly impervious surfaces. The perforated pipe connections will be unable to provide infiltration of the stormwater runoff because of the underlying non-native fill soils. Other Impervious Surfaces • Basic Dispersion (Appendix C, Section C2.4 of the RSWDM) – Basic Dispersion is not feasible due to the lack of pervious surfaces on site. There is no vegetated flow path for the stormwater runoff on site. On-site flow control BMPs will not be feasible within the project area due to the lack of pervious surfaces and sufficient space on-site. The implementation of on-site flow control BMPs would not be practical since the project area is located within an airport, where the majority of the site consists of impervious land cover. Infiltration is not feasible due to the underlying soil consisting of fill material. 4.5 Water Quality Since the project area will be adding more than 5,000 square feet of new impervious surface, the project is required to provide water quality treatment on-site. The project will implement MWS-Linear Modular Wetland structures upstream of the discharge point for two separate storm drain lines. The project site is divided into the North and South drainage basins. See Figure 3 for the Drainage Basin map. The North drainage basin consists of 3.43 acres of impervious surface and generates an off-line water quality flow rate of 0.3148 cfs. The North drainage basin will implement the MWS-L-8-12-V-UG structure for water quality treatment. The South drainage basin consists of 4.96 acres of impervious surface (4.03 acres onsite and 0.93 acres offsite) and generates an off-line water quality flow rate of 0.4553 cfs. The South drainage basin will not collect any of the proposed building’s roof runoff and will bypass the water quality treatment structure. The MWS-L-8-20-V-UG structure will be implemented in the south drainage basin for water quality treatment. 26 In addition, due to the site characteristics of an industrial site, oil water separator structures will be used within the storm drainage system. The North and South drainage basins will use the 816-1-CPS Oil Water Separator structure from Oldcastle Precast. These oil water separator structures will be placed just upstream of the Modular Wetland structures in order to trap the oil before treatment. The WWHM reports for the water quality flow rates for each basin can be found in Appendix B. See Appendix C for the MWS-Linear Modular Wetland and oil water separator standard details. 4.6 Flow Splitter According to the RSWDM, the project is only required to treat flows up to and including the Water Quality design flow rate. In order to achieve this, the project will implement flow splitter structures in both North and South drainage basins. The flow splitters will be located upstream of the Modular Wetland structures and the oil-water separators in order to split off only the treatment flow to the downstream treatment facilities. By splitting the water quality design flows, it enables the downstream treatment facilities to be sized according to the smaller treatment flow rates. This helps the project implement the most efficient design and cut down on construction and maintenance costs for the treatment facilities. The flow splitter design calculations can be found in Appendix H. 27 Figure 8: Existing Conditions RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C226R C8 90% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C227R C9 90% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C228R C9 60% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C229R C10 60% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C230R C11 60% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL RENTON SITE PAVEMENT REMOVAL AND TESC PLAN C231R C12 60% DESIGN REVIEW NOT FOR CONSTRUCTIONREMOVAL 28 Figure 9: Proposed Conditions RENTON SITE COMPOSITE CIVIL SITE PLAN C4 C4 GALVANIZATION NOTE 90% DESIGN REVIEW NOT FOR CONSTRUCTION GV FLOW InletOutlet RENTON SITE COMPOSITE CIVIL SITE PLAN C5 C5 GALVANIZATION NOTE 90% DESIGN REVIEW NOT FOR CONSTRUCTION BOEING 737-MAX10BOEING 737-MAX1060% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE COMPOSITE CIVIL SITE PLAN C6 C4 GALVANIZATION NOTE 29 5.0 CONVEYANCE SYSTEM ANALYSIS & DESIGN In accordance with the RSWDM, pipe capacities and backwater analysis for the private conveyance systems were calculated using the SBUH method. The pipe capacities were analyzed by applying the 25- year peak flow rate. The backwater analysis was completed by applying the 100-year peak flow rate in order to confirm if the water surface elevation of Lake Washington would overtop the surcharge elevation of the on-site catch basins. Conveyance calculations were performed using Autodesk Storm and Sanitary Analysis 2016. The results confirmed that the proposed pipe sizes are adequate for conveying the 25-year peak flow rate. Additionally, the 100-year peak flow rate will not cause any proposed catch basins to overtop. The conveyance calculations can be found in Appendix D. 30 6.0 SPECIAL REPORTS & STUDIES • Stormwater Pollution Prevention Plan (CSWPPP) (Appendix A) 31 7.0 OTHER PERMITS The following additional permits are anticipated for this project: • SEPA Permit • Civil Construction Permit • Building Permit • Construction Stormwater General Permit (CSWGP) – required since the project will disturb more that 1.0 acre of land. 32 8.0 CWSPPP ANALYSIS AND DESIGN 8.1 Erosion and Sediment Control (ESC) Measures 8.1.1 Clearing Limits Prior to beginning earth disturbing activities on the site, the Contractor shall delineate the clearing limits which will be spray painted with white paint on the edge of the existing concrete panels to be removed. During the construction period, no disturbance beyond the marked clearing limits shall be permitted. The marking shall be maintained by the Contractor for the duration of construction. 8.1.2 Cover Measures The existing asphalt and concrete will remain in place as long as possible. Any exposed disturbed soil will need to be stabilized at the end of each shift. Plastic covering is the most practical means of accomplishing this. 8.1.3 Perimeter Protection The perimeter will have a temporary safety fence. In the perimeter areas on the downhill side a triangular silt dike is to be installed. This triangular silt dike works similar to a silt fence but can easily be installed on existing pavement. The filter fabric traps the sediment so that it can be removed after reaching a depth of four inches. 8.1.4 Traffic Area Stabilization Currently this access is paved, and will be used as existing pavement as long as possible. Once the asphalt is removed, a construction entrance will be installed. If the construction entrance is not providing enough protection then a wheel wash will be installed. 8.1.5 Sediment Retention It is not anticipated that the site will generate significant quantities of sediment laden runoff. The project will utilize storm drain inlet protection and localized TESC measures to prevent sediment laden water leaving the site. Triangular silt dike will also be installed adjacent to all disturbed areas to minimize the transport of sediment. 8.1.6 Surface Water Collection Surface water will be collected by the proposed storm system. Catch basins and clean outs will be used to collect and convey stormwater runoff. The construction area will discharge into the existing storm system located in Apron D, directly west of the project site. 8.1.7 Dewatering Control Since the project proposes work that will require excavating six feet below existing grade, dewatering is anticipated for this project. Dewatering control BMPs will be required. 33 8.1.8 Dust Control If dust becomes a problem, then the area shall be sprayed with water until wet, but no runoff shall be generated by spraying. 8.1.9 Flow Control Flow control will not be provided for this project on-site. 8.1.10 Control Pollutants The following measures will be taken: • All vehicles, equipment and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance. • Fueling will be conducted on hard pavement. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. • Process water and slurry resulting from concrete work will be prevented from entering waters of the state by implementing Concrete Handling measures (BMP C151), pH neutralization will be utilized if necessary. 8.1.11 Protect Existing and Proposed Flow Control BMPS Protection measures shall be installed to prevent impacts to existing and proposed flow control BMPs. Triangular silt dike and storm drain inlet protection shall be used to protect existing and proposed flow control BMPs. 8.1.12 Maintain BMPs The Contractor shall be responsible for maintaining and repairing all temporary and permanent erosion and sediment control BMPs throughout construction. All temporary erosion and sediment control BMPs shall be removed prior to final construction approval, or within 30 days after achieving final site stabilization. 8.1.13 Manage the Project Construction will take place during the dry season. All BMPs shall be inspected, maintained and repaired as needed throughout all phases of construction. Site inspections and monitoring shall be documented. The contractor shall update the SWPPP as necessary and keep a copy on site at all times. 8.2 SWPPS Measures 8.2.1 Pollutant Handling and Disposal The following measures will be taken: 34 • All vehicles, equipment and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance. • Fueling will be conducted on hard pavement. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. • Process water and slurry resulting from concrete work will be prevented from entering waters of the state by implementing Concrete Handling measures (BMP C151), pH neutralization will be utilized if necessary. 8.2.2 Cover and Containment for Materials, Fuel and Other Pollutants Temporary storage areas shall be located away from vehicular traffic, near the construction entrances, and away from waterways or storm drains. The storage and handling of hazardous materials shall be minimized whenever possible. Construction materials shall be covered in wet weather. 8.2.3 Manage the Project Site See Section 8.1.13 for managing the project. 8.2.4 Protect from Spills and Drips The BMPs listed in Section 8.2.1 and 8.2.2 shall be used to protect from spills and drips. 8.2.5 Avoid Overapplication or Untimely Application of Chemicals and Fertilizers Chemicals and fertilizers shall be prohibited for this project. 8.2.6 Prevent or Treat Contamination of Stormwater Runoff All BMPs listed in Section 8.1 and 8.2 shall be used to prevent contamination of stormwater runoff. 8.3 SWPPP Plan Design The Stormwater Pollution Prevention Plan (SWPPP) is a stand-alone document that describes the Construction Best Management Practices (BMP’s). The SWPPP has been prepared under a separate cover, but is attached in Appendix A of this report. The 13 elements and BMPs recommended are identified below: 8.3.1 Element 1 – Preserve Vegetation / Mark Clearing Limits Prior to beginning earth disturbing activities on the site, the Contractor shall delineate the clearing limits which will be spray painted with white paint on the edge of the existing concrete panels to be removed. During the construction period, no disturbance beyond the marked clearing limits shall be permitted. The marking shall be maintained by the Contractor for the duration of construction. 35 8.3.2 Element 2 – Establish Construction Access The site is currently paved and the asphalt will remain in place as long as possible. Once the driveway asphalt is removed a construction entrance per the City of Renton standard detail 215.10 could be employed. Sequentially a construction entrance might not be necessary. Wheel washing, street sweeping and street cleaning shall be employed as necessary to prevent sediment from tracking onto the Perimeter Road. 8.3.3 Element 3 – Control Flow Rates Flow control will not be provided for this project on-site. 8.3.4 Element 4 – Install Sediment Controls It is not anticipated that the site will generate significant quantities of sediment laden runoff. The project will utilize storm drain inlet protection and localized TESC measures to prevent sediment laden water leaving the site. Triangular silt dike will also be installed adjacent to all disturbed areas to minimize the transport of sediment. 8.3.5 Element 5 – Stabilize Soils The existing asphalt and concrete will remain in place as long as possible. Exposed and unworked soils shall be stabilized with Plastic Coverings per City of Renton standard detail 213.30 or an equivalent protection. 8.3.6 Element 6 – Protect Slopes The site is relatively flat, where there are no slopes. 8.3.7 Element 7 – Protect Drain Inlets Storm drain inlet protection will be installed per City of Renton standard detail 216.30 on all catch basins located within the construction area and immediately downstream of the project areas. 8.3.8 Element 8 – Stabilize Channels and Outlets The stormwater runoff will be directly released into the existing storm system in Apron D, just west of the project area. 8.3.9 Element 9 – Control Pollutants The following measures will be taken: • All vehicles, equipment and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance. • Fueling will be conducted on hard pavement. • Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. • In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. 36 • Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. • Process water and slurry resulting from concrete work will be prevented from entering waters of the state by implementing Concrete Handling measures, pH neutralization will be utilized if necessary. 8.3.10 Element 10 – Control Dewatering Since the project proposes work that will require excavating six feet below existing grade, dewatering is anticipated for this project. Dewatering control BMPs will be required. 8.3.11 Element 11 – Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be inspected, maintained and repaired as needed to ensure continued performance of their intended function. 8.3.12 Element 12 – Manage the Project During construction consideration shall be given to removing and replacing the pavement in stages. Site inspections and monitoring will be conducted in accordance with Special Conditions S4 of the CSWGP. The contractor will update the SWPPP as necessary and keep a copy on site at all times. 8.3.13 Element 13 – Protect Low Impact Development (LID) There are no LID BMPs proposed for this project. If it becomes necessary, the BMPs listed in Elements 1- 12 shall be used to protect LID BMPs. 37 9.0 BOND QUANTITIES, FACILITY SUMMARIES, AND DECLARATION OF COVENANT 9.1 Bond Quantities The standard City of Renton bond quantity worksheet is included in Appendix F. 9.2 Flow Control and Water Quality Facility Summary Sheet and Sketch N/A 9.3 Declaration of Covenant for Privately Maintained Flow Control and Water Quality Facilities All stormwater facilities proposed will be privately owned and maintained. 38 10.0 OPERATIONS & MAINTENANCE MANUAL The Operations & Maintenance Manual will be developed in the future submittal. The manual document is meant to be a standalone document and will be incorporated into the larger Boeing operational program. The final Operations & Maintenance Manual will be published post construction with the as-built drawings and full documentation of equipment cut sheet submittals and manufacturer’s maintenance procedures. Appendix A SWPPP Plans Construction Stormwater General Permit Stormwater Pollution Prevention Plan (SWPPP) for Apron E Stalls and Paint Hangar Prepared for: Prepared for: The Washington State Department of Ecology City of Renton, WA Northwest Regional Office 3190 – 160th Avenue SE Bellevue, WA 98008 Permittee / Owner Developer Operator / Contractor Boeing Commercial Airplanes TBD TBD Project Site Location Renton Municipal Airport City of Renton, WA Certified Erosion and Sediment Control Lead (CESCL) Name Organization Contact Phone Number TBD TBD TBD SWPPP Prepared By Name Organization Contact Phone Number Jason Shrope DOWL 425-869-2670 SWPPP Preparation Date 12 / 06 / 2019 Project Construction Dates Activity / Phase Start Date End Date TBD TBD TBD P a g e | 1 Table of Contents 1 Project Information .............................................................................................................. 4 1.1 Existing Conditions ...................................................................................................... 4 1.2 Proposed Construction Activities .................................................................................. 4 2 Construction Stormwater Best Management Practices (BMPs) ........................................... 6 2.1 The 13 Elements .......................................................................................................... 6 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits ........................................ 6 2.1.2 Element 2: Establish Construction Access ............................................................ 7 2.1.3 Element 3: Control Flow Rates ............................................................................. 8 2.1.4 Element 4: Install Sediment Controls .................................................................... 9 2.1.5 Element 5: Stabilize Soils ....................................................................................10 2.1.6 Element 6: Protect Slopes....................................................................................11 2.1.7 Element 7: Protect Drain Inlets ............................................................................12 2.1.8 Element 8: Stabilize Channels and Outlets ..........................................................13 2.1.9 Element 9: Control Pollutants ...............................................................................14 2.1.10 Element 10: Control Dewatering ..........................................................................16 2.1.11 Element 11: Maintain BMPs .................................................................................17 2.1.12 Element 12: Manage the Project ..........................................................................18 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs .................................21 3 Pollution Prevention Team .................................................................................................22 4 Monitoring and Sampling Requirements ............................................................................23 4.1 Site Inspection ............................................................................................................23 4.2 Stormwater Quality Sampling ......................................................................................23 4.2.1 Turbidity Sampling ...............................................................................................23 4.2.2 pH Sampling ........................................................................................................25 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies .........................26 5.1 303(d) Listed Waterbodies ..........................................................................................26 5.2 TMDL Waterbodies .....................................................................................................26 6 Reporting and Record Keeping ..........................................................................................27 6.1 Record Keeping ..........................................................................................................27 6.1.1 Site Log Book ......................................................................................................27 6.1.2 Records Retention ...............................................................................................27 6.1.3 Updating the SWPPP ...........................................................................................27 6.2 Reporting ....................................................................................................................28 6.2.1 Discharge Monitoring Reports ..............................................................................28 6.2.2 Notification of Noncompliance ..............................................................................28 P a g e | 2 List of Tables Table 1 – Summary of Site Pollutant Constituents ................................................................. 4 Table 2 – Pollutants ................................................................................................................ 14 Table 3 – pH-Modifying Sources ............................................................................................ 15 Table 4 – Dewatering BMPs .................................................................................................... 16 Table 5 – Management ............................................................................................................ 18 Table 6 – BMP Implementation Schedule .............................................................................. 19 Table 7 – Team Information .................................................................................................... 22 Table 8 – Turbidity Sampling Method .................................................................................... 23 Table 9 – pH Sampling Method .............................................................................................. 25 List of Appendices A. Site Map B. BMP Detail C. Correspondence D. Site Inspection Form E. Construction Stormwater General Permit (CSWGP) F. 303(d) List Waterbodies / TMDL Waterbodies Information G. Contaminated Site Information H. Engineering Calculations P a g e | 3 List of Acronyms and Abbreviations Acronym / Abbreviation Explanation 303(d) Section of the Clean Water Act pertaining to Impaired Waterbodies BFO Bellingham Field Office of the Department of Ecology BMP(s) Best Management Practice(s) CESCL Certified Erosion and Sediment Control Lead CO2 Carbon Dioxide CRO Central Regional Office of the Department of Ecology CSWGP Construction Stormwater General Permit CWA Clean Water Act DMR Discharge Monitoring Report DO Dissolved Oxygen Ecology Washington State Department of Ecology EPA United States Environmental Protection Agency ERO Eastern Regional Office of the Department of Ecology ERTS Environmental Report Tracking System ESC Erosion and Sediment Control GULD General Use Level Designation NPDES National Pollutant Discharge Elimination System NTU Nephelometric Turbidity Units NWRO Northwest Regional Office of the Department of Ecology pH Power of Hydrogen RCW Revised Code of Washington SPCC Spill Prevention, Control, and Countermeasure su Standard Units SWMMEW Stormwater Management Manual for Eastern Washington SWMMWW Stormwater Management Manual for Western Washington SWPPP Stormwater Pollution Prevention Plan TESC Temporary Erosion and Sediment Control SWRO Southwest Regional Office of the Department of Ecology TMDL Total Maximum Daily Load VFO Vancouver Field Office of the Department of Ecology WAC Washington Administrative Code WSDOT Washington Department of Transportation WWHM Western Washington Hydrology Model P a g e | 4 1 Project Information Project/Site Name: Apron E Expansion Project Street/Location: Intersection of Logan Ave N / N 6th St City: Renton State: WA Zip code: 98057 Subdivision: N/A Receiving waterbody: Lake Washington 1.1 Existing Conditions Total acreage (including support activities such as off-site equipment staging yards, material storage areas, borrow areas). Total acreage: 9.82 Acres Disturbed acreage: 9.82 Acres Existing structures: Boeing S1 Parking Lot Landscape topography: Flat Drainage patterns: Parking lot runoff is collected with an existing stormdrain system and conveyed west into the existing storm system on Apron D. Existing Vegetation: Landscaped area throughout and around the perimeter of the existing parking lot. Critical Areas (wetlands, streams, high erosion risk, steep or difficult to stabilize slopes): Seizmic hazard areas. List of known impairments for 303(d) listed or Total Maximum Daily Load (TMDL) for the receiving waterbody: Lake Washington is 303(d) listed for Bacteria and Total Phosphorus. Table 1 includes a list of suspected and/or known contaminants associated with the construction activity. Table 1 – Summary of Site Pollutant Constituents Constituent (Pollutant) Location Depth Concentration None 1.2 Proposed Construction Activities Description of site development (example: subdivision): P a g e | 5 This project proposes to construct three airplane stalls, a paint hangar, and a utility maintenance building on the existing Boeing S1 parking lot. The project porposes to connect to the existing storm system on Apron D, just west of the project site. Construction will impact approximately 10.45 acres. Description of construction activities (example: site preparation, demolition, excavation): The project will include the construction of the following elements: • Clearing and grubbing • Demolition and excavation • Utilities – storm, sewer and water • Impervious surface replacement • Storm drain conveyance connection to existing storm system Description of site drainage including flow from and onto adjacent properties. Must be consistent with Site Map in Appendix A: All stormwater is collected on-site via the proposed storm drain system and conveyed west until it discharges to the existing downstream conveyance system on Apron D. There is no contributing flow from or onto adjacent properties. Description of final stabilization (example: extent of revegetation, paving, landscaping): The site will be stabilized with pavement and landscaping. Contaminated Site Information: Proposed activities regarding contaminated soils or groundwater (example: on-site treatment system, authorized sanitary sewer discharge): There are no proposed activities regarding contaminated soils or groundwater. P a g e | 6 2 Construction Stormwater Best Management Practices (BMPs) The SWPPP is a living document reflecting current conditions and changes throughout the life of the project. These changes may be informal (i.e., hand-written notes and deletions). Update the SWPPP when the CESCL or local agency has noted a deficiency in BMPs or deviation from original design. 2.1 The 13 Elements 2.1.1 Element 1: Preserve Vegetation / Mark Clearing Limits To protect adjacent properties and to reduce the area of soil exposed to construction, the limits of construction will be clearly marked before land-disturbing activities begin. Trees that are to be preserved, as well as all sensitive areas and their buffers, shall be clearly delineated in the field. In general, natural vegetation and native topsoil shall be retained in an undisturbed state to the maximum extent possible. A protective barrier shall be placed aound the protected trees prior to land preparation or construction activities, and shall remain in place until all construction activity is terminated. No equipment, chemicals, soil deposits or construction materials shall be placed within the protective barriers. Any landscaping activities subsequent to the removal of the barriers shall be accomplished with light machinery or hand labor. (LMC 17.15.160 B1) Prior to beginning earth disturbing activities on the site, the Contractor shall delineate the clearing limits which will be spray painted with white paint on the edge of the existing concrete panels to be removed. During the construction period, no disturbance beyond the marked clearing limits shall be permitted. The marking shall be maintained by the Contractor for the duration of construction. List and describe BMPs: • Plastic or Metal Fence (BMP D.2.1.1.1) (if necessary) Installation Schedules: Prior to beginning construction activities Inspection and Maintenance plan: Weekly observation Responsible Staff: Contractor P a g e | 7 2.1.2 Element 2: Establish Construction Access Construction access or activities occurring on unpaved areas shall be minimized, yet where necessary, access points shall be stabilized to minimize the tracking of sediment onto public roads, and wheel washing, street sweeping, and street cleaning shall be employed to prevent sediment from entering state waters. All wash wastewater shall be controlled on site. Currently this access is paved, and will be used as existing pavement as long as possible. Once the asphalt is removed, a construction entrance will be installed. If the construction entrance is not providing enough protection then a wheel wash will be installed. List and describe BMPs: • Stabilized Construction Entrance (BMP D.2.1.4.1) (if necessary) • Construction Road/Parking Area Stabilization (BMP D.2.1.4.2) • Wheel Wash (BMP D.2.1.4.3) (if necessary) Installation Schedules: These will be implemented for the duration of construction Inspection and Maintenance plan: As necessary Responsible Staff: Contractor P a g e | 8 2.1.3 Element 3: Control Flow Rates In order to protect the properties and waterways downstream of the project site, stormwater discharges from the site will be controlled. There are no specific BMPs for flow control that shall be used on this project. The project site is located west of the Cascade Mountain Crest. As such, the project must comply with Core Requirement 3. In general, discharge rates of stormwater from the site will be controlled where increases in impervious area or soil compaction during construction could lead to downstream erosion, or where necessary to meet local agency stormwater discharge requirements (e.g. discharge to combined sewer systems). Flow control will not be provided for this project on-site since the project area is designated as being exempt from flow control requirements. Will you construct stormwater retention and/or detention facilities? Yes No Will you use permanent infiltration ponds or other low impact development (example: rain gardens, bio-retention, porous pavement) to control flow during construction? Yes No List and describe BMPs: N/A Installation Schedules: N/A Inspection and Maintenance plan: N/A Responsible Staff: N/A P a g e | 9 2.1.4 Element 4: Install Sediment Controls All stormwater runoff from disturbed areas shall pass through an appropriate sediment removal BMP before leaving the construction site or prior to being discharged to an infiltration facility. The specific BMPs to be used for controlling sediment on this project include: • Triangular Silt Dike (BMP D.2.1.3.4) • Storm Drain Inlet Protection (BMP D.2.1.5.3) To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. In addition, sediment will be removed from paved areas in and adjacent to construction work areas manually or using mechanical sweepers, as needed, to minimize tracking of sediments on vehicle tires away from the site and to minimize washoff of sediments from adjacent streets in runoff. Whenever possible, sediment laden water shall be discharged into onsite, relatively level, vegetated areas. Installation Schedules: Prior to beginning construction activities Inspection and Maintenance plan: Weekly inspection and after storm events Responsible Staff: Contractor P a g e | 10 2.1.5 Element 5: Stabilize Soils Exposed and unworked soils shall be stabilized with the application of effective BMPs to prevent erosion throughout the life of the project. The specific BMPs for soil stabilization that shall be used on this project include: • Plastic Covering (BMP D.2.1.2.4) • Dust Control (BMP D.2.1.8) The project site is located west of the Cascade Mountain Crest. As such, no soils shall remain exposed and unworked for more than 7 days during the dry season (May 1 to September 30) and 2 days during the wet season (October 1 to April 30). Regardless of the time of year, all soils shall be stabilized at the end of the shift before a holiday or weekend if needed based on weather forecasts. In general, cut and fill slopes will be stabilized as soon as possible and soil stockpiles will be temporarily covered with plastic sheeting. All stockpiled soils shall be stabilized from erosion, protected with sediment trapping measures, and where possible, be located away from storm drain inlets, waterways, and drainage channels. West of the Cascade Mountains Crest Season Dates Number of Days Soils Can be Left Exposed During the Dry Season May 1 – September 30 7 days During the Wet Season October 1 – April 30 2 days Soils must be stabilized at the end of the shift before a holiday or weekend if needed based on the weather forecast. Anticipated project dates: Start date: TBD End date: TBD Will you construct during the wet season? Yes No Installation Schedules: Implemented as soil is exposed Inspection and Maintenance plan: Daily Responsible Staff: Contractor P a g e | 11 2.1.6 Element 6: Protect Slopes All cut and fill slopes will be designed, constructed, and protected in a manner than minimizes erosion. The project site is relatively flat, where there are no slopes. It is not antipicated to require the protection of slopes, but the following specific BMPs will be used to protect slopes for this project as necessary: • Temporary and Permanent Seeding (BMP D.2.1.2.6) (if necessary) Will steep slopes be present at the site during construction? Yes No Installation Schedules: As necessary – no impacted slopes on-site Inspection and Maintenance plan: As necessary Responsible Staff: Contractor P a g e | 12 2.1.7 Element 7: Protect Drain Inlets All storm drain inlets and culverts made operable during construction shall be protected to prevent unfiltered or untreated water from entering the drainage conveyance system. However, the first priority is to keep all access roads clean of sediment and keep street wash water separate from entering storm drains until treatment can be provided. Storm Drain Inlet Protection (BMP D.2.1.5.3) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site. If the BMP option listed above are deemed ineffective or inappropriate during construction to satisfy the requirements set forth in the General NPDES Permit, the Certified Erosion and Sediment Control Lead shall implement one or more of the alternative BMP inlet protection options. Installation Schedules: Prior to beginning construction activities Inspection and Maintenance plan: Weekly inspection and after storm events Responsible Staff: Contractor P a g e | 13 2.1.8 Element 8: Stabilize Channels and Outlets Where site runoff is to be conveyed in channels, or discharged to a stream or some other natural drainage point, efforts will be taken to prevent downstream erosion. The specific BMPs for channel and outlet stabilization that shall be used on this project include: • N/A – no channels or outlets on-site or included in project The project site is located west of the Cascade Mountain Crest. As such, all temporary on-site conveyance channels shall be designed, constructed, and stabilized to prevent erosion from the expected peak 10 minute velocity of flow from a Type 1A, 10-year, 24-hour recurrence interval storm for the developed condition. Alternatively, the 10-year, 1-hour peak flow rate indicated by an approved continuous runoff simulation model, increased by a factor of 1.6, shall be used. Stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent streambanks, slopes, and downstream reaches shall be provided at the outlets of all conveyance systems. Provide stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes, and downstream reaches, will be installed at the outlets of all conveyance systems. Installation Schedules: N/A Inspection and Maintenance plan:N/A Responsible Staff: N/A P a g e | 14 2.1.9 Element 9: Control Pollutants All pollutants, including waste materials and demolition debris, that occur onsite shall be handled and disposed of in a manner that does not cause contamination of stormwater. Good housekeeping and preventative measures will be taken to ensure that the site will be kept clean, well organized, and free of debris. If required, BMPs to be implemented to control specific sources of pollutants are discussed below. Vehicles, construction equipment, and/or petroleum product storage/dispensing: ▪ All vehicles, equipment, and petroleum product storage/dispensing areas will be inspected regularly to detect any leaks or spills, and to identify maintenance needs to prevent leaks or spills. ▪ Fueling will be conducted on hard pavement. ▪ Spill prevention measures, such as drip pans, will be used when conducting maintenance and repair of vehicles or equipment. ▪ In order to perform emergency repairs on site, temporary plastic will be placed beneath and, if raining, over the vehicle. ▪ Contaminated surfaces shall be cleaned immediately following any discharge or spill incident. ▪ Process water and slurry resulting from concrete work will be prevented from entering water of the state by implementing Concrete Handling measures, pH neutralization will be utilized if necessary. If applicable, the Contractor shall prepare an SPCC Plan according to the Washington State Department of Transportation (W SDOT) Requirements (see the WSDOT Standard Specifications for Road, Bridge, and Municipal Construction 2018). The following pollutants are anticipated to be present on-site: Table 2 – Pollutants Pollutant (List pollutants and source, if applicable) Gasoline – Fuel for vehicles Hydraulic Oil – Operator’s equipment Installation Schedules: Implemented for the duration of construction Inspection and Maintenance plan: Weekly inspection Responsible Staff: Contractor Will maintenance, fueling, and/or repair of heavy equipment and vehicles occur on-site? Yes No P a g e | 15 Will wheel wash or tire bath system BMPs be used during construction? Yes No Will pH-modifying sources be present on-site? Yes No Table 3 – pH-Modifying Sources None Bulk cement Cement kiln dust Fly ash Other cementitious materials New concrete washing or curing waters Waste streams generated from concrete grinding and sawing Exposed aggregate processes Dewatering concrete vaults Concrete pumping and mixer washout waters Recycled concrete Recycled concrete stockpiles Other (i.e., calcium lignosulfate) [please describe: ] Concrete trucks must not be washed out onto the ground, or into storm drains, open ditches, streets, or streams. Excess concrete must not be dumped on-site, except in designated concrete washout areas with appropriate BMPs installed. Excess concrete must be returned to the plant for recycling if there are no concrete washout areas with appropriate BMPs installed. Will uncontaminated water from water-only based shaft drilling for construction of building, road, and bridge foundations be infiltrated provided the wastewater is managed in a way that prohibits discharge to surface waters? Yes No P a g e | 16 2.1.10 Element 10: Control Dewatering All dewatering water from open cut excavation, tunneling, foundation work, trench, or underground vaults shall be discharged into a controlled conveyance system prior to discharge to a sediment trap or sediment pond. Channels will be stabilized, per Element #8. Clean, non- turbid dewatering water will not be routed through stormwater sediment ponds, and will be discharged to systems tributary to the receiving waters of the State in a manner that does not cause erosion, flooding, or a violation of State water quality standards in the receiving water. Highly turbid dewatering water from soils known or suspected to be contaminated, or from use of construction equipment, will require additional monitoring and treatment as required for the specific pollutants based on the receiving waters into which the discharge is occurring. Such monitoring is the responsibility of the contractor. However, the dewatering of soils known to be free of contamination will trigger BMPs to trap sediment and reduce turbidity. At a minimum, geotextile fabric socks/bags/cells will be used to filter this material. To avoid potential erosion and sediment control issues that may cause a violation(s) of the NPDES Construction Stormwater permit, the Certified Erosion and Sediment Control Lead will promptly initiate the implementation of one or more of the alternative BMPs after the first sign that existing BMPs are ineffective or failing. Table 4 – Dewatering BMPs Infiltration Transport off-site in a vehicle (vacuum truck for legal disposal) Ecology-approved on-site chemical treatment or other suitable treatment technologies Sanitary or combined sewer discharge with local sewer district approval (last resort) Use of sedimentation bag with discharge to ditch or swale (small volumes of localized dewatering) Installation Schedules: During construction Inspection and Maintenance plan: As necessary throughout construction Responsible Staff: Contractor P a g e | 17 2.1.11 Element 11: Maintain BMPs All temporary and permanent Erosion and Sediment Control (ESC) BMPs shall be maintained and repaired as needed to ensure continued performance of their intended function. Maintenance and repair shall be conducted in accordance with each particular BMP specification (see Volume II of the SWMMWW or Chapter 7 of the SWMMEW). Visual monitoring of all BMPs installed at the site will be conducted at least once every calendar week and within 24 hours of any stormwater or non-stormwater discharge from the site. If the site becomes inactive and is temporarily stabilized, the inspection frequency may be reduced to once every calendar month. All temporary ESC BMPs shall be removed within 30 days after final site stabilization is achieved or after the temporary BMPs are no longer needed. Trapped sediment shall be stabilized on-site or removed. Disturbed soil resulting from removal of either BMPs or vegetation shall be permanently stabilized. Additionally, protection must be provided for all BMPs installed for the permanent control of stormwater from sediment and compaction. BMPs that are to remain in place following completion of construction shall be examined and restored to full operating condition. If sediment enters these BMPs during construction, the sediment shall be removed and the facility shall be returned to conditions specified in the construction documents. P a g e | 18 2.1.12 Element 12: Manage the Project The project will be managed based on the following principles: • Projects will be phased to the maximum extent practicable and seasonal work limitations will be taken into account. • Inspection and monitoring: o Inspection, maintenance and repair of all BMPs will occur as needed to ensure performance of their intended function. o Site inspections and monitoring will be conducted in accordance with Special Condition S4 of the CSWGP. Sampling locations are indicated on the Site Map. Sampling station(s) are located in accordance with applicable requirements of the CSWGP. • Maintain an updated SWPPP. o The SWPPP will be updated, maintained, and implemented in accordance with Special Conditions S3, S4, and S9 of the CSWGP. As site work progresses the SWPPP will be modified routinely to reflect changing site conditions. The SWPPP will be reviewed monthly to ensure the content is current. Table 5 – Management Design the project to fit the existing topography, soils, and drainage patterns Emphasize erosion control rather than sediment control Minimize the extent and duration of the area exposed Keep runoff velocities low Retain sediment on-site Thoroughly monitor site and maintain all ESC measures Schedule major earthwork during the dry season Other (please describe) P a g e | 19 Table 6 – BMP Implementation Schedule Phase of Construction Project Stormwater BMPs Date Wet/Dry Season Phase of Construction Project Stormwater BMPs Date Wet/Dry Season P a g e | 20 [Insert construction activity] [Insert BMP] [MM/DD/YYYY] [Insert Season] P a g e | 21 2.1.13 Element 13: Protect Low Impact Development (LID) BMPs The project will not proposed any LID BMPs for this site. If it becomes necessary, the BMPs listed in Elements 1-12 shall be used to protect LID BMPs. P a g e | 22 3 Pollution Prevention Team Table 7 – Team Information Title Name(s) Phone Number Certified Erosion and Sediment Control Lead (CESCL) TBD TBD Resident Engineer TBD 425-869-2670 Emergency Ecology Contact Rob Walls 425-649-7130 Emergency Permittee/ Owner Contact Mark Clement 206-617-2944 Non-Emergency Owner Contact Mark Clement 206-617-2944 Monitoring Personnel TBD TBD Ecology Regional Office Northwest Regional Office 425-649-7000 P a g e | 23 4 Monitoring and Sampling Requirements Monitoring includes visual inspection, sampling for water quality parameters of concern, and documentation of the inspection and sampling findings in a site log book. A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Stormwater sampling data The site log book must be maintained on-site within reasonable access to the site and be made available upon request to Ecology or the local jurisdiction. The receiving waterbody, Lake Washington, is impaired for: Bacteria and Total Phosphorus. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25NTU for turbidity. 4.1 Site Inspection Site inspections will be conducted at least once every calendar week and within 24 hours following any discharge from the site. For sites that are temporarily stabilized and inactive, the required frequency is reduced to once per calendar month. The discharge point(s) is located at the existing catch basin structure at the west end of the property. 4.2 Stormwater Quality Sampling 4.2.1 Turbidity Sampling Requirements include calibrated turbidity meter or transparency tube to sample site discharges for compliance with the CSWGP. Sampling will be conducted at all discharge points at least once per calendar week. Method for sampling turbidity: Table 8 – Turbidity Sampling Method Turbidity Meter/Turbidimeter (required for disturbances 5 acres or greater in size) Transparency Tube (option for disturbances less than 1 acre and up to 5 acres in size) The benchmark for turbidity value is 25 nephelometric turbidity units (NTU) and a transparency less than 33 centimeters. If the discharge’s turbidity is 26 to 249 NTU or the transparency is less than 33 cm but equal to or greater than 6 cm, the following steps will be conducted: 1. Review the SWPPP for compliance with Special Condition S9. Make appropriate revisions within 7 days of the date the discharge exceeded the benchmark. P a g e | 24 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period. 3. Document BMP implementation and maintenance in the site log book. If the turbidity exceeds 250 NTU or the transparency is 6 cm or less at any time, the following steps will be conducted: 1. Telephone or submit an electronic report to the applicable Ecology Region’s Environmental Report Tracking System (ERTS) within 24 hours. • Northwest Region (King, Kitsap, Island, San Juan, Skagit, Snohomish, Whatcom): (425) 649-7000 or http://www.ecy.wa.gov/programs/spills/forms/nerts_online/NWRO_nerts_online.html 2. Immediately begin the process to fully implement and maintain appropriate source control and/or treatment BMPs as soon as possible. Address the problems within 10 days of the date the discharge exceeded the benchmark. If installation of necessary treatment BMPs is not feasible within 10 days, Ecology may approve additional time when the Permittee requests an extension within the initial 10-day response period 3. Document BMP implementation and maintenance in the site log book. 4. Continue to sample discharges daily until one of the following is true: • Turbidity is 25 NTU (or lower). • Transparency is 33 cm (or greater). • Compliance with the water quality limit for turbidity is achieved. o 1 - 5 NTU over background turbidity, if background is less than 50 NTU o 1% - 10% over background turbidity, if background is 50 NTU or greater • The discharge stops or is eliminated. P a g e | 25 4.2.2 pH Sampling pH monitoring is required for “Significant concrete work” (i.e., greater than 1000 cubic yards poured concrete over the life of the project). The use of recycled concrete or engineered soils (soil amendments including but not limited to Portland cement-treated base [CTB], cement kiln dust [CKD] or fly ash) also requires pH monitoring. For significant concrete work, pH sampling will start the first day concrete is poured and continue until it is cured, typically three (3) weeks after the last pour. For engineered soils and recycled concrete, pH sampling begins when engineered soils or recycled concrete are first exposed to precipitation and continues until the area is fully stabilized. If the measured pH is 8.5 or greater, the following measures will be taken: 1. Prevent high pH water from entering storm sewer systems or surface water. 2. Adjust or neutralize the high pH water to the range of 6.5 to 8.5 su using appropriate technology such as carbon dioxide (CO2) sparging (liquid or dry ice). 3. Written approval will be obtained from Ecology prior to the use of chemical treatment other than CO2 sparging or dry ice. Method for sampling pH: Table 9 – pH Sampling Method pH meter pH test kit Wide range pH indicator paper P a g e | 26 5 Discharges to 303(d) or Total Maximum Daily Load (TMDL) Waterbodies 5.1 303(d) Listed Waterbodies Is the receiving water 303(d) (Category 5) listed for turbidity, fine sediment, phosphorus, or pH? Yes No List the impairment(s): The receiving waterbody, Lake Washington, is impaired for: Bacteria and Total Phosphorus. All stormwater and dewatering discharges from the site are subject to an effluent limit of 8.5 su for pH and/or 25NTU for turbidity 5.2 TMDL Waterbodies Waste Load Allocation for CWSGP discharges: N/A List and describe BMPs: N/A Discharges to TMDL receiving waterbodies will meet in-stream water quality criteria at the point of discharge. The Construction Stormwater General Permit Proposed New Discharge to an Impaired Water Body form is included in Appendix F. P a g e | 27 6 Reporting and Record Keeping 6.1 Record Keeping 6.1.1 Site Log Book A site log book will be maintained for all on-site construction activities and will include: • A record of the implementation of the SWPPP and other permit requirements • Site inspections • Sample logs 6.1.2 Records Retention Records will be retained during the life of the project and for a minimum of three (3) years following the termination of permit coverage in accordance with Special Condition S5.C of the CSWGP. Permit documentation to be retained on-site: • CSWGP • Permit Coverage Letter • SWPPP • Site Log Book Permit documentation will be provided within 14 days of receipt of a written request from Ecology. A copy of the SWPPP or access to the SWPPP will be provided to the public when requested in writing in accordance with Special Condition S5.G.2.b of the CSWGP. 6.1.3 Updating the SWPPP The SWPPP will be modified if: • Found ineffective in eliminating or significantly minimizing pollutants in stormwater discharges from the site. • There is a change in design, construction, operation, or maintenance at the construction site that has, or could have, a significant effect on the discharge of pollutants to waters of the State. The SWPPP will be modified within seven (7) days if inspection(s) or investigation(s) determine additional or modified BMPs are necessary for compliance. An updated timeline for BMP implementation will be prepared. P a g e | 28 6.2 Reporting 6.2.1 Discharge Monitoring Reports Cumulative soil disturbance is one (1) acre or larger; therefore, Discharge Monitoring Reports (DMRs) will be submitted to Ecology monthly. If there was no discharge during a given monitoring period the DMR will be submitted as required, reporting “No Discharge”. The DMR due date is fifteen (15) days following the end of each calendar month. DMRs will be reported online through Ecology’s WQWebDMR System. 6.2.2 Notification of Noncompliance If any of the terms and conditions of the permit is not met, and the resulting noncompliance may cause a threat to human health or the environment, the following actions will be taken: 1. Ecology will be notified within 24-hours of the failure to comply by calling the applicable Regional office ERTS phone number (Regional office numbers listed below). 2. Immediate action will be taken to prevent the discharge/pollution or otherwise stop or correct the noncompliance. If applicable, sampling and analysis of any noncompliance will be repeated immediately and the results submitted to Ecology within five (5) days of becoming aware of the violation. 3. A detailed written report describing the noncompliance will be submitted to Ecology within five (5) days, unless requested earlier by Ecology. Anytime turbidity sampling indicates turbidity is 250 NTUs or greater, or water transparency is 6 cm or less, the Ecology Regional office will be notified by phone within 24 hours of analysis as required by Special Condition S5.A of the CSWGP. • Northwest Region at (425) 649-7000 for Island, King, Kitsap, San Juan, Skagit, Snohomish, or Whatcom County Include the following information: 1. Your name and / Phone number 2. Permit number 3. City / County of project 4. Sample results 5. Date / Time of call 6. Date / Time of sample 7. Project name In accordance with Special Condition S4.D.5.b of the CSWGP, the Ecology Regional office will be notified if chemical treatment other than CO2 sparging is planned for adjustment of high pH water. P a g e | 29 A. Site Map RENTON SITE COMPOSITE CIVIL SITE PLAN C4 C4 GALVANIZATION NOTE 90% DESIGN REVIEW NOT FOR CONSTRUCTION GV FLOW InletOutlet RENTON SITE COMPOSITE CIVIL SITE PLAN C5 C5 GALVANIZATION NOTE 90% DESIGN REVIEW NOT FOR CONSTRUCTION BOEING 737-MAX10BOEING 737-MAX1060% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE COMPOSITE CIVIL SITE PLAN C6 C4 GALVANIZATION NOTE P a g e | 30 B. BMP Detail The following BMPs will be implemented for this project: • Plastic or Metal Fence (BMP D.2.1.1.1) (if necessary) • Plastic Covering (BMP D.2.1.2.4) • Temporary and Permanent Seeding (BMP D.2.1.2.6) (if necessary) • Triangular Silt Dike (BMP D.2.1.3.4) • Stabilized Construction Entrance (BMP D.2.1.4.1) (if necessary) • Construction Road/Parking Area Stabilization (BMP D.2.1.4.2) • Wheel Wash (BMP D.2.1.4.3) (if necessary) • Storm Drain Inlet Protection (BMP D.2.1.5.3) • Dust Control (BMP D.2.1.8) SECTION D.2.1 ESC MEASURES protection is warranted. Permanent fencing may also be used if desired by the applicant. Silt fence, in combination with survey flagging, is also an acceptable method of marking critical areas and their buffers. D.2.1.1.1 PLASTIC OR METAL FENCE Code: FE Symbol: Purpose Fencing is intended to (1) restrict clearing to approved limits; (2) prevent disturbance of critical areas, their buffers, and other areas required to be left undisturbed; (3) limit construction traffic to designated construction entrances or roads; and (4) protect areas where marking with survey tape may not provide adequate protection. Conditions of Use To establish clearing limits, plastic or metal fence may be used: 1. At the boundary of critical areas, their buffers, and other areas required to be left uncleared. 2. As necessary to control vehicle access to and on the site (see Sections D.2.1.4.1 and D.2.1.4.2). Design and Installation Specifications 1. The fence shall be designed and installed according to the manufacturer's specifications. 2. The fence shall be at least 3 feet high and must be highly visible. 3. The fence shall not be wired or stapled to trees. Maintenance Requirements 1. If the fence has been damaged or visibility reduced, it shall be repaired or replaced immediately and visibility restored. 2. Disturbance of a critical area, critical area buffer, native growth retention area, or any other area required to be left undisturbed shall be reported to the County for resolution. D.2.1.2 COVER MEASURES Temporary and permanent cover measures shall be provided to protect all disturbed areas, including the faces of cut and fill slopes. Temporary cover shall be installed if an area is to remain unworked for more than seven days during the dry season (May 1 to September 30) or for more than two consecutive working days during the wet season (October 1 to April 30). These time limits may be relaxed if an area poses a low risk of erosion due to soil type, slope gradient, anticipated weather conditions, or other factors. Conversely, the County may reduce these time limits if site conditions warrant greater protection (e.g., adjacent to significant aquatic resources or highly erosive soils) or if significant precipitation (see Section D.2.4.2) is expected. Any area to remain unworked for more than 30 days shall be seeded or sodded, unless the County determines that winter weather makes vegetation establishment infeasible. During the wet season, slopes and stockpiles at 3H:1V or steeper and with more than ten feet of vertical relief shall be covered if they are to remain unworked for more than 12 hours. Also during the wet season, the material necessary to cover all disturbed areas must be stockpiled on site. The intent of these cover requirements is to have as much area as possible covered during any period of precipitation. Purpose: The purpose of covering exposed soils is to prevent erosion, thus reducing reliance on less effective methods that remove sediment after it is entrained in runoff. Cover is the only practical method of reducing turbidity in runoff. Structural measures, such as silt fences and sediment ponds, are only capable of removing coarse particles and in most circumstances have little to no effect on turbidity. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-12 SECTION D.2.1 ESC MEASURES D.2.1.2.4 PLASTIC COVERING Code: PC Symbol: Purpose Plastic covering provides immediate, short-term erosion protection to slopes and disturbed areas. Conditions of Use 1. Plastic covering may be used on disturbed areas that require cover measures for less than 30 days. 2. Plastic is particularly useful for protecting cut and fill slopes and stockpiles. Note: The relatively rapid breakdown of most polyethylene sheeting makes it unsuitable for long-term applications. 3. Clear plastic sheeting may be used over newly-seeded areas to create a greenhouse effect and encourage grass growth. Clear plastic should not be used for this purpose during the summer months because the resulting high temperatures can kill the grass. 4. Due to rapid runoff caused by plastic sheeting, this method shall not be used upslope of areas that might be adversely impacted by concentrated runoff. Such areas include steep and/or unstable slopes. Note: There have been many problems with plastic, usually attributable to poor installation and maintenance. However, the material itself can cause problems, even when correctly installed and maintained, because it generates high-velocity runoff and breaks down quickly due to ultraviolet radiation. In addition, if the plastic is not completely removed, it can clog drainage system inlets and outlets. It is highly recommended that alternatives to plastic sheeting be used whenever possible and that its use be limited. Design and Installation Specifications 1. See Figure D.2.1.2.D for details. 2. Plastic sheeting shall have a minimum thickness of 0.06 millimeters. 3. If erosion at the toe of a slope is likely, a gravel berm, riprap, or other suitable protection shall be installed at the toe of the slope in order to reduce the velocity of runoff. FIGURE D.2.1.2.D PLASTIC COVERING TIRES, SANDBAGS, OR EQUIVALENT MAY BE USED TO WEIGHT PLASTIC SEAMS BETWEEN SHEETS MUST OVERLAP A MINIMUM OF 12" AND BE WEIGHTED OR TAPED TOE IN SHEETING IN MINIMUM 4"X4" TRENCH PROVIDE ENERGY DISSIPATION AT TOE WHEN NEEDED 10' MAX. 10' MAX. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-20 D.2.1.2 COVER MEASURES Maintenance Standards for Plastic Covering 1. Torn sheets must be replaced and open seams repaired. 2. If the plastic begins to deteriorate due to ultraviolet radiation, it must be completely removed and replaced. 3. When the plastic is no longer needed, it shall be completely removed. D.2.1.2.5 STRAW WATTLES Code: SW Symbol: Purpose Wattles are erosion and sediment control barriers consisting of straw wrapped in biodegradable tubular plastic or similar encasing material. Wattles may reduce the velocity and can spread the flow of rill and sheet runoff, and can capture and retain sediment. Straw wattles are typically 8 to 10 inches in diameter and 25 to 30 feet in length. The wattles are placed in shallow trenches and staked along the contour of disturbed or newly constructed slopes. Conditions of Use 1. Install on disturbed areas that require immediate erosion protection. 2. Use on slopes requiring stabilization until permanent vegetation can be established. 3. Can be used along the perimeter of a project, as a check dam in unlined ditches and around temporary stockpiles 4. Wattles can be staked to the ground using willow cuttings for added revegetation. 5. Rilling can occur beneath and between wattles if not properly entrenched, allowing water to pass below and between wattles Design and Installation Specifications 1. It is critical that wattles are installed perpendicular to the flow direction and parallel to the slope contour. 2. Narrow trenches should be dug across the slope, on contour, to a depth of 3 to 5 inches on clay soils and soils with gradual slopes. On loose soils, steep slopes, and during high rainfall events, the trenches should be dug to a depth of 5 to 7 inches, or ½ to 2/3 of the thickness of the wattle. 3. Start construction of trenches and installing wattles from the base of the slope and work uphill. Excavated material should be spread evenly along the uphill slope and compacted using hand tamping or other method. Construct trenches at contour intervals of 3 to 30 feet apart depending on the steepness of the slope, soil type, and rainfall. The steeper the slope the closer together the trenches should be constructed. 4. Install the wattles snugly into the trenches and abut tightly end to end. Do not overlap the ends. 5. Install stakes at each end of the wattle, and at 4 foot centers along the entire length of the wattle. 6. If required, install pilot holes for the stakes using a straight bar to drive holes through the wattle and into the soil. 7. At a minimum, wooden stakes should be approximately ¾ x ¾ x 24 inches. Willow cuttings or 3/8 inch rebar can also be used for stakes. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-21 SECTION D.2.1 ESC MEASURES D.2.1.2.6 TEMPORARY AND PERMANENT SEEDING Code: SE Symbol: Purpose Seeding is intended to reduce erosion by stabilizing exposed soils. A well-established vegetative cover is one of the most effective methods of reducing erosion. Conditions of Use 1. Seeding shall be used throughout the project on disturbed areas that have reached final grade or that will remain unworked for more than 30 days. 2. Vegetation-lined channels shall be seeded. Channels that will be vegetated should be installed before major earthwork and hydroseeded or covered with a Bonded Fiber Matrix (BFM). 3. Retention/detention ponds shall be seeded as required. 4. At the County's discretion, seeding without mulch during the dry season is allowed even though it will take more than seven days to develop an effective cover. Mulch is, however, recommended at all times because it protects seeds from heat, moisture loss, and transport due to runoff. 5. At the beginning of the wet season, all disturbed areas shall be reviewed to identify which ones can be seeded in preparation for the winter rains (see Section D.2.4.2). Disturbed areas shall be seeded within one week of the beginning of the wet season. A sketch map of those areas to be seeded and those areas to remain uncovered shall be submitted to the DPER inspector. The DPER inspector may require seeding of additional areas in order to protect surface waters, adjacent properties, or drainage facilities. 6. At final site stabilization, all disturbed areas not otherwise vegetated or stabilized shall be seeded and mulched (see Section D.2.4.5). Design and Installation Specifications 1. The best time to seed is April 1 through June 30, and September 1 through October 15. Areas may be seeded between July 1 and August 31, but irrigation may be required in order to grow adequate cover. Areas may also be seeded during the winter months, but it may take several months to develop a dense groundcover due to cold temperatures. The application and maintenance of mulch is critical for winter seeding. 2. To prevent seed from being washed away, confirm that all required surface water control measures have been installed. 3. The seedbed should be firm but not compacted because soils that are well compacted will not vegetate as quickly or thoroughly. Slopes steeper than 3H:1V shall be surface roughened. Roughening can be accomplished in a variety of ways, but the typical method is track walking, or driving a crawling tractor up and down the slope, leaving cleat imprints parallel to the slope contours. 4. In general, 10-20-20 N-P-K (nitrogen-phosphorus-potassium) fertilizer may be used at a rate of 90 pounds per acre. Slow-release fertilizers are preferred because they are more efficient and have fewer environmental impacts. It is recommended that areas being seeded for final landscaping conduct soil tests to determine the exact type and quantity of fertilizer needed. This will prevent the over- application of fertilizer. Disturbed areas within 200 feet of water bodies and wetlands must use slow- release low-phosphorus fertilizer (typical proportions 3-1-2 N-P-K). 5. The following requirements apply to mulching: a) Mulch is always required for seeding slopes greater than 3H:1V (see Section D.2.1.2.2). 4/24/2016 2016 Surface Water Design Manual – Appendix D D-24 D.2.1.2 COVER MEASURES b) If seeding during the wet season, mulch is required. c) The use of mulch may be required during the dry season at the County's discretion if grass growth is expected to be slow, the soils are highly erodible due to soil type or gradient, there is a water body close to the disturbed area, or significant precipitation (see Section D.2.4.2) is anticipated before the grass will provide effective cover. d) Mulch may be applied on top of the seed or simultaneously by hydroseeding. 6. Hydroseeding is allowed as long as tackifier is included. Hydroseeding with wood fiber mulch is adequate during the dry season. During the wet season, the application rate shall be doubled because the mulch and tackifier used in hydroseeding break down fairly rapidly. It may be necessary in some applications to include straw with the wood fiber, but this can be detrimental to germination. 7. Areas to be permanently landscaped shall use soil amendments. Good quality topsoil shall be tilled into the top six inches to reduce the need for fertilizer and improve the overall soil quality. Most native soils will require the addition of four inches of well-rotted compost to be tilled into the soil to provide a good quality topsoil. Compost used should meet specifications provided in Reference 11-C of the SWDM. 8. The seed mixes listed below include recommended mixes for both temporary and permanent seeding. These mixes, with the exception of the wetland mix, shall be applied at a rate of 120 pounds per acre. This rate may be reduced if soil amendments or slow-release fertilizers are used. Local suppliers should be consulted for their recommendations because the appropriate mix depends on a variety of factors, including exposure, soil type, slope, and expected foot traffic. Alternative seed mixes approved by the County may be used. Table D.2.1.2.B presents the standard mix for those areas where just a temporary vegetative cover is required. TABLE D.2.1.2.B TEMPORARY EROSION CONTROL SEED MIX % Weight % Purity % Germination Chewings or red fescue Festuca rubra var. commutata or Festuca rubra 40 98 90 Annual or perennial rye Lolium multiflorum or Lolium perenne 40 98 90 Redtop or colonial bentgrass Agrostis alba or Agrostis tenuis 10 92 85 White dutch clover Trifolium repens 10 98 90 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-25 SECTION D.2.1 ESC MEASURES Table D.2.1.2.C provides just one recommended possibility for landscaping seed. TABLE D.2.1.2.C LANDSCAPING SEED MIX % Weight % Purity % Germination Perennial rye blend Lolium perenne 70 98 90 Chewings and red fescue blend Festuca rubra var. commutata or Festuca rubra 30 98 90 This turf seed mix in Table D.2.1.2.D is for dry situations where there is no need for much water. The advantage is that this mix requires very little maintenance. TABLE D.2.1.2.D LOW-GROWING TURF SEED MIX % Weight % Purity % Germination Dwarf tall fescue (several varieties) Festuca arundinacea var. 45 98 90 Dwarf perennial rye (Barclay) Lolium perenne var. barclay 30 98 90 Red fescue Festuca rubra 20 98 90 Colonial bentgrass Agrostis tenuis 5 98 90 Table D.2.1.2.E presents a mix recommended for bioswales and other intermittently wet areas. Sod shall generally not be used for bioswales because the seed mix is inappropriate for this application. Sod may be used for lining ditches to prevent erosion, but it will provide little water quality benefit during the wet season. TABLE D.2.1.2.E BIOSWALE SEED MIX* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 75-80 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 92 85 Redtop bentgrass Agrostis alba or Agrostis gigantea 5-10 90 80 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix 4/24/2016 2016 Surface Water Design Manual – Appendix D D-26 D.2.1.2 COVER MEASURES The seed mix shown in Table D.2.1.2.F is a recommended low-growing, relatively non-invasive seed mix appropriate for very wet areas that are not regulated wetlands (if planting in wetland areas, see Section 6.3.1 of the King County Surface Water Design Manual). Other mixes may be appropriate, depending on the soil type and hydrology of the area. Apply this mixture at a rate of 60 pounds per acre. TABLE D.2.1.2.F WET AREA SEED MIX* % Weight % Purity % Germination Tall or meadow fescue Festuca arundinacea or Festuca elatior 60-70 98 90 Seaside/Creeping bentgrass Agrostis palustris 10-15 98 85 Meadow foxtail Alepocurus pratensis 10-15 90 80 Alsike clover Trifolium hybridum 1-6 98 90 Redtop bentgrass Agrostis alba 1-6 92 85 * Modified Briargreen, Inc. Hydroseeding Guide Wetlands Seed Mix The meadow seed mix in Table D.2.1.2.G is recommended for areas that will be maintained infrequently or not at all and where colonization by native plants is desirable. Likely applications include rural road and utility right-of-way. Seeding should take place in September or very early October in order to obtain adequate establishment prior to the winter months. The appropriateness of clover in the mix may need to be considered as this can be a fairly invasive species. If the soil is amended, the addition of clover may not be necessary. TABLE D.2.1.2.G MEADOW SEED MIX % Weight % Purity % Germination Redtop or Oregon bentgrass Agrostis alba or Agrostis oregonensis 40 92 85 Red fescue Festuca rubra 40 98 90 White dutch clover Trifolium repens 20 98 90 Maintenance Standards for Temporary and Permanent Seeding 1. Any seeded areas that fail to establish at least 80 percent cover within one month shall be reseeded. If reseeding is ineffective, an alternate method, such as sodding or nets/blankets, shall be used. If winter weather prevents adequate grass growth, this time limit may be relaxed at the discretion of the County when critical areas would otherwise be protected. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-27 SECTION D.2.1 ESC MEASURES 2. After adequate cover is achieved, any areas that experience erosion shall be re-seeded and protected by mulch. If the erosion problem is drainage related, the problem shall be fixed and the eroded area re-seeded and protected by mulch. 3. Seeded areas shall be supplied with adequate moisture, but not watered to the extent that it causes runoff. D.2.1.2.7 SODDING Code: SO Symbol: Purpose The purpose of sodding is to establish permanent turf for immediate erosion protection and to stabilize drainage ways where concentrated overland flow will occur. Conditions of Use Sodding may be used in the following areas: 1. Disturbed areas that require short-term or long-term cover 2. Disturbed areas that require immediate vegetative cover 3. All waterways that require vegetative lining (except biofiltration swales—the seed mix used in most sod is not appropriate for biofiltration swales). Waterways may also be seeded rather than sodded, and protected with a net or blanket (see Section D.2.1.2.3). Design and Installation Specifications Sod shall be free of weeds, of uniform thickness (approximately 1-inch thick), and shall have a dense root mat for mechanical strength. The following steps are recommended for sod installation: 1. Shape and smooth the surface to final grade in accordance with the approved grading plan. 2. Amend four inches (minimum) of well-rotted compost into the top eight inches of the soil if the organic content of the soil is less than ten percent. Compost used shall meet compost specifications per SWDM Reference 11-C. 3. Fertilize according to the supplier's recommendations. Disturbed areas within 200 feet of water bodies and wetlands must use non-phosphorus fertilizer. 4. Work lime and fertilizer 1 to 2 inches into the soil, and smooth the surface. 5. Lay strips of sod beginning at the lowest area to be sodded and perpendicular to the direction of water flow. Wedge strips securely into place. Square the ends of each strip to provide for a close, tight fit. Stagger joints at least 12 inches. Staple on slopes steeper than 3H:1V. 6. Roll the sodded area and irrigate. 7. When sodding is carried out in alternating strips or other patterns, seed the areas between the sod immediately after sodding. Maintenance Standards If the grass is unhealthy, the cause shall be determined and appropriate action taken to reestablish a healthy groundcover. If it is impossible to establish a healthy groundcover due to frequent saturation, instability, or some other cause, the sod shall be removed, the area seeded with an appropriate mix, and protected with a net or blanket. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-28 D.2.1.3 PERIMETER PROTECTION D.2.1.3.3 VEGETATED STRIP Code: VS Symbol: Purpose Vegetated strips reduce the transport of coarse sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Conditions of Use 1. Vegetated strips may be used downslope of all disturbed areas. 2. Vegetated strips are not intended to treat concentrated flows, nor are they intended to treat substantial amounts of overland flow. Any concentrated flows must be conveyed through the drainage system to a sediment trap or pond. The only circumstance in which overland flow may be treated solely by a strip, rather than by a sediment trap or pond, is when the area draining to the strip is small (see "Criteria for Use as Primary Treatment" on page D-33). Design and Installation Specifications 1. The vegetated strip shall consist of a 25-foot minimum width continuous strip of dense vegetation with a permeable topsoil. Grass-covered, landscaped areas are generally not adequate because the volume of sediment overwhelms the grass. Ideally, vegetated strips shall consist of undisturbed native growth with a well-developed soil that allows for infiltration of runoff. 2. The slope within the strip shall not exceed 4H:1V. 3. The uphill boundary of the vegetated strip shall be delineated with clearing limits as specified in Section D.2.1.1 (p. D-11). Maintenance Standards 1. Any areas damaged by erosion or construction activity shall be seeded immediately and protected by mulch. 2. If more than 5 feet of the original vegetated strip width has had vegetation removed or is being eroded, sod must be installed using the standards for installation found in Section D.2.1.2.7. If there are indications that concentrated flows are traveling across the buffer, surface water controls must be installed to reduce the flows entering the buffer, or additional perimeter protection must be installed. D.2.1.3.4 TRIANGULAR SILT DIKE (GEOTEXTILE ENCASED CHECK DAM) Code: TSD Symbol: Purpose Triangular silt dikes (TSDs) may be used as check dams, for perimeter protection, for temporary soil stockpile protection, for drop inlet protection, or as a temporary interceptor dike. Silt dikes, if attached to impervious surfaces with tack or other adhesive agent may also be used as temporary wheel wash areas, or concrete washout collection areas. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-37 SECTION D.2.1 ESC MEASURES Conditions of Use 1. May be used for temporary check dams in ditches. 2. May be used on soil or pavement with adhesive or staples. 3. TSDs have been used to build temporary sediment ponds, diversion ditches, concrete washout facilities, curbing, water bars, level spreaders, and berms. Design and Installation Specifications 1. TSDs must be made of urethane foam sewn into a woven geosynthetic fabric. 2. TSDs are triangular, 10 inches to 14 inches high in the center, with a 20-inch to 28-inch base. A 2- foot apron extends beyond both sides of the triangle along its standard section of 7 feet. A sleeve at one end allows attachment of additional sections as needed 3. Install TSDs with ends curved up to prevent water from flowing around the ends 4. Attach the TSDs and their fabric flaps to the ground with wire staples. Wire staples must be No. 11 gauge wire or stronger and shall be 200 mm to 300 mm in length. 5. When multiple units are installed, the sleeve of fabric at the end of the unit shall overlap the abutting unit and be stapled. 6. TSDs must be located and installed as soon as construction will allow. 7. TSDs must be placed perpendicular to the flow of water. 8. When used as check dams, the leading edge must be secured with rocks, sandbags, or a small key slot and staples. 9. When used in grass-lined ditches and swales, the TSD check dams and accumulated sediment shall be removed when the grass has matured sufficiently to protect the ditch or swale unless the slope of the swale is greater than 4 percent. The area beneath the TSD check dams shall be seeded and mulched immediately after dam removal. Maintenance Standards 1. Triangular silt dikes shall be monitored for performance and sediment accumulation during and after each runoff producing rainfall event. Sediment shall be removed when it reaches one half the height of the silt dike. 2. Anticipate submergence and deposition above the triangular silt dike and erosion from high flows around the edges of the dike/dam. Immediately repair any damage or any undercutting of the dike/dam. D.2.1.3.5 COMPOST BERMS Code: COBE Symbol: Purpose Compost berms are an option to meet the requirements of perimeter protection. Compost berms may reduce the transport of sediment from a construction site by providing a temporary physical barrier to sediment and reducing the runoff velocities of overland flow. Compost berms trap sediment by filtering water passing through the berm and allowing water to pond, creating a settling area for solids behind the berm. Organic materials in the compost can also reduce concentrations of metals and petroleum hydrocarbons from construction runoff. Due to the increase in phosphorous seen in the effluent data from compost berms, they should be used with some cautions in areas that drain to phosphorus sensitive water 4/24/2016 2016 Surface Water Design Manual – Appendix D D-38 SECTION D.2.1 ESC MEASURES D.2.1.4.1 STABILIZED CONSTRUCTION ENTRANCE Code: CE Symbol: Purpose Construction entrances are stabilized to reduce the amount of sediment transported onto paved roads by motor vehicles or runoff by constructing a stabilized pad of quarry spalls at entrances to construction sites. Conditions of Use Construction entrances shall be stabilized wherever traffic will be leaving a construction site and traveling on paved roads or other paved areas within 1,000 feet of the site. Access and exits shall be limited to one route if possible, or two for linear projects such as roadway where more than one access/exit is necessary for maneuvering large equipment. For residential construction provide stabilized construction entrances for each residence in addition to the main subdivision entrance. Stabilized surfaces shall be of sufficient length/width to provide vehicle access/parking, based on lot size/configuration. Design and Installation Specifications 1. See Figure D.2.1.4.A for details. 2. A separation geotextile shall be placed under the spalls to prevent fine sediment from pumping up into the rock pad. The geotextile shall meet the following standards: Grab Tensile Strength (ASTM D4632) 200 lbs min. Grab Tensile Elongation (ASTM D4632) 30% max.(woven) Puncture Strength (ASTM D6241) 495 lbs min. AOS (ASTM D4751) 20-45 (U.S. standard sieve size) 3. Do not use crushed concrete, cement, or calcium chloride for construction entrance stabilization because these products raise pH levels in stormwater and concrete discharge to surface waters of the State is prohibited. 4. Hog fuel (wood based mulch) may be substituted for or combined with quarry spalls in areas that will not be used for permanent roads. The effectiveness of hog fuel is highly variable, but it has been used successfully on many sites. It generally requires more maintenance than quarry spalls. Hog fuel is not recommended for entrance stabilization in urban areas. The inspector may at any time require the use of quarry spalls if the hog fuel is not preventing sediment from being tracked onto pavement or if the hog fuel is being carried onto pavement. Hog fuel is prohibited in permanent roadbeds because organics in the subgrade soils cause difficulties with compaction. 5. Fencing (see Section D.2.1.1) shall be installed as necessary to restrict traffic to the construction entrance. 6. Whenever possible, the entrance shall be constructed on a firm, compacted subgrade. This can substantially increase the effectiveness of the pad and reduce the need for maintenance. Maintenance Standards 1. Quarry spalls (or hog fuel) shall be added if the pad is no longer in accordance with the specifications. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-42 D.2.1.4 TRAFFIC AREA STABILIZATION 2. If the entrance is not preventing sediment from being tracked onto pavement, then alternative measures to keep the streets free of sediment shall be used. This may include street sweeping, an increase in the dimensions of the entrance, or the installation of a wheel wash. If washing is used, it shall be done on an area covered with crushed rock, and wash water shall drain to a sediment trap or pond. 3. Any sediment that is tracked onto pavement shall be removed immediately by sweeping. The sediment collected by sweeping shall be removed or stabilized on site. The pavement shall not be cleaned by washing down the street, except when sweeping is ineffective and there is a threat to public safety. If it is necessary to wash the streets, a small sump must be constructed. The sediment would then be washed into the sump where it can be controlled. Wash water must be pumped back onto the site and cannot discharge to systems tributary to surface waters. 4. Any quarry spalls that are loosened from the pad and end up on the roadway shall be removed immediately. 5. If vehicles are entering or exiting the site at points other than the construction entrance(s), fencing (see Section D.2.1.1) shall be installed to control traffic. FIGURE D.2.1.4.A STABILIZED CONSTRUCTION ENTRANCE •PER KING COUNTY ROAD DESIGN AND CONSTRUCTION STANDARDS (KCRDCS), DRIVEWAYS SHALL BE PAVED TO EDGE OF R-O-W PRIOR TO INSTALLATION OF THE CONSTRUCTION ENTRANCE TO AVOID DAMAGING OF THE ROADWAY. •IT IS RECOMMENDED THAT THE ENTRANCE BE CROWNED SO THAT RUNOFF DRAINS OFF THE PAD. 12" MIN. THICKNESS PROVIDE FULL WIDTH OF INGRESS/EGRESS AREA IF A ROADSIDE DITCH IS PRESENT, INSTALL DRIVEWAY CULVERT PER KCRDCS GEOTEXTILE 4"- 8" QUARRY SPALLS R=25' MIN. 100' M I N . EXISTI N G R O A D 15' MIN. NOTES: 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-43 SECTION D.2.1 ESC MEASURES D.2.1.4.2 CONSTRUCTION ROAD/PARKING AREA STABILIZATION Code: CRS Symbol: Purpose Stabilizing subdivision roads, parking areas and other onsite vehicle transportation routes immediately after grading reduces erosion caused by construction traffic or runoff. Conditions of Use 1. Roads or parking areas shall be stabilized wherever they are constructed, whether permanent or temporary, for use by construction traffic. 2. Fencing (see Section D.2.1.1) shall be installed, if necessary, to limit the access of vehicles to only those roads and parking areas that are stabilized. Design and Installation Specifications 1. A 6-inch depth of 2- to 4-inch crushed rock, gravel base, or crushed surfacing base course shall be applied immediately after grading or utility installation. A 4-inch course of asphalt treated base (ATB) may also be used, or the road/parking area may be paved. It may also be possible to use cement or calcium chloride for soil stabilization. If the area will not be used for permanent roads, parking areas, or structures, a 6-inch depth of hog fuel may also be used, but this is likely to require more maintenance. Whenever possible, construction roads and parking areas shall be placed on a firm, compacted subgrade. Note: If the area will be used for permanent road or parking installation later in the project, the subgrade will be subject to inspection. 2. Temporary road gradients shall not exceed 15 percent. Roadways shall be carefully graded to drain transversely. Drainage ditches shall be provided on each side of the roadway in the case of a crowned section, or on one side in the case of a super-elevated section. Drainage ditches shall be designed in accordance with the standards given in Section D.2.1.6.4 (p. D-64) and directed to a sediment pond or trap. 3. Rather than relying on ditches, it may also be possible to grade the road so that runoff sheet-flows into a heavily vegetated area with a well-developed topsoil. Landscaped areas are not adequate. If this area has at least 50 feet of vegetation, then it is generally preferable to use the vegetation to treat runoff, rather than a sediment pond or trap. The 50 feet shall not include vegetated wetlands. If runoff is allowed to sheet flow through adjacent vegetated areas, it is vital to design the roadways and parking areas so that no concentrated runoff is created. 4. In order to control construction traffic, the County may require that signs be erected on site informing construction personnel that vehicles, other than those performing clearing and grading, are restricted to stabilized areas. 5. If construction roads do not adequately reduce trackout to adjacent property or roadways, a wheel wash system will be required. Maintenance Standards Crushed rock, gravel base, hog fuel, etc. shall be added as required to maintain a stable driving surface and to stabilize any areas that have eroded. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-44 D.2.1.4 TRAFFIC AREA STABILIZATION D.2.1.4.3 WHEEL WASH Code: WW Symbol: Purpose Wheel wash systems reduce the amount of sediment transported onto paved roadways and into surface water systems by construction vehicles. Conditions of Use When a stabilized construction entrance is not preventing sediment from being tracked onto pavement: • Wheel washing is generally an effective erosion and sediment control method and BMP when installed with careful attention to topography. For example, a wheel wash can be detrimental if installed at the top of a slope abutting a right-of-way where the water from the dripping truck wheels and undercarriage can run unimpeded into the street. • Pressure washing combined with an adequately sized and properly surfaced wash pad with direct drainage discharge to a large 10 foot x 10-foot sump can be very effective. Design and Installation Specifications A suggested detail is shown in Figure D.2.1.4.B. 1. A minimum of 6inches of asphalt treated base (ATB) over crushed base material or 8 inches over a good subgrade is recommended to pave the wheel wash area. 2. Use a low clearance truck to test the wheel wash before paving. Either a belly dump or lowboy will work well to test clearance. 3. Keep the water level from 12 to 14 inches deep to avoid damage to truck hubs and filling the truck tongues with water. 4. Midpoint spray nozzles are only needed in very muddy conditions. 5. Wheel wash systems should be designed with a small grade change, 6 to 12 inches for a 10-foot wide pond, to allow sediment to flow to the low side of the pond and to help prevent re-suspension of sediment. 6. A drainpipe with a 2 to 3 foot riser should be installed on the low side of the wheel wash pond to allow for easy cleaning and refilling. Polymers may be used to promote coagulation and flocculation in a closed-loop system. 7. Polyacrylamide (PAM) added to the wheel washwater at a rate of 0.25 – 0.5 pounds per 1,000 gallons of water increases effectiveness and reduces cleanup time. If PAM is already being used for dust or erosion control and is being applied by a water truck, the same truck may be used to change the washwater. Maintenance Standards 1. The wheel wash should start out each day with clean, fresh water. 2. The washwater should be changed a minimum of once per day. On large earthwork jobs where more than 10-20 trucks per hour are expected, the washwater will need to be changed more often. 3. Wheel wash or tire bath wastewater shall be discharged to a separate on-site treatment system, such as a closed-loop recirculation system or land application, or to the sanitary sewer system with proper local sewer district approval or permits. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-45 SECTION D.2.1 ESC MEASURES FIGURE D.2.1.4.B WHEEL WASH AND PAVED CONSTRUCTION ENTRANCE 2% SLOPE 15'15'20'15'50' 18' 12' 3' 5' BUILD 8'x8' SUMP TO ACCOMODATE CLEANING BY TRACKHOE.SECTION A-A NTS 8'x8' SUMP, SEE NOTE LOCATE INVERT OF TOP PIPE 1' ABOVE BOTTOM OF WHEEL WASH DRAIN PIPE 1:1 SLOPE WATER LEVEL ELEVATION VIEW NTS PLAN VIEW NTS 6" SLEEVE CURB ASPHALT CURB ON THE LOW ROAD SIDE TO DIRECT WATER BACK TO POND 6" ATB CONSTRUCTION ENTRANCE 1-1/2" SCHEDULE 40 FOR SPRAYERS 2% SLOPE MIDPOINT SPRAY NOZZLES, IF NEEDED 3" TRASH PUMP WITH FLOATS ON SUCTION HOSE 2" SCHEDULE 40 6" SLEEVE UNDER ROAD 8'x8' SUMP WITH 5' OF CATCH 6" SEWER PIPE WITH BUTTERFLY VALVES 1:1 SLOPE A A 5:1 SLOPE 5:1 SLOPE 15' ATB APRON TO PROTECT GROUND FROM SPLASHING WATER BALL VALVES NOTE: 4/24/2016 2016 Surface Water Design Manual – Appendix D D-46 D.2.1.5 SEDIMENT RETENTION FIGURE D.2.1.5.D SEDIMENT POND RISER DETAIL 3.5' MIN. 18" MIN. 2X RISER DIA. MIN. CORRUGATED METAL RISER CONCRETE BASE ALTERNATIVELY, METAL STAKES AND WIRE MAY BE USED TO PREVENT FLOTATION DEWATERING ORIFICE, SCHEDULE 40 STEEL STUB MIN. DIAMETER AS PER CALCULATIONS 6" MIN. PROVIDE ADEQUATE STRAPPING POLYETHYLENE CAP PERFORATED DEWATERING DEVICE, SEE NOTE WATERTIGHT COUPLING TACK WELD NOTE: PERFORATED CORRUGATED POLYETHYLENE (CPE) DRAINAGE TUBING, DIAMETER MIN. 2" LARGER THAN DEWATERING ORIFICE. TUBING SHALL COMPLY WITH ASTM F667 AND AASHTO M294. D.2.1.5.3 STORM DRAIN INLET PROTECTION Code: FFP or CBI or CBP Symbol: or or Purpose Storm drain inlets are protected to prevent coarse sediment from entering storm drainage systems. Temporary devices around storm drains assist in improving the quality of water discharged to inlets or catch basins by ponding sediment-laden water. These devices are effective only for relatively small drainage areas. Conditions of Use 1. Protection shall be provided for all storm drain inlets downslope and within 500 feet of a disturbed or construction area, unless the runoff that enters the catch basin will be conveyed to a sediment pond or trap. 2. Inlet protection may be used anywhere at the applicant's discretion to protect the drainage system. This will, however, require more maintenance, and it is highly likely that the drainage system will still require some cleaning. 3. The contributing drainage area must not be larger than one acre. Design and Installation Specifications 1. There are many options for protecting storm drain inlets. Two commonly used options are filter fabric protection and catch basin inserts. Filter fabric protection (see Figure D.2.1.5.E) is filter fabric (geotextile) placed over the grate. This method is generally very ineffective and requires intense maintenance efforts. Catch basin inserts (see Figure D.2.1.5.F) are manufactured devices that nest inside a catch basin. This method also requires a high frequency of maintenance to be effective. Both 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-53 SECTION D.2.1 ESC MEASURES options provide adequate protection, but filter fabric is likely to result in ponding of water above the catch basin, while the insert will not. Thus, filter fabric is only allowed where ponding will not be a traffic concern and where slope erosion will not result if the curb is overtopped by ponded water. Trapping sediment in the catch basins is unlikely to improve the water quality of runoff if it is treated in a pond or trap because the coarse particles that are trapped at the catch basin settle out very quickly in the pond or trap. Catch basin protection normally only improves water quality where there is no treatment facility downstream. In these circumstances, catch basin protection is an important last line of defense. It is not, however, a substitute for preventing erosion. The placement of filter fabric under grates is generally prohibited and the use of filter fabric over grates is strictly limited and discouraged. 2. It is sometimes possible to construct a small sump around the catch basin before final surfacing of the road. This is allowed because it can be a very effective method of sediment control. 3. Block and gravel filters, gravel and wire mesh filter barriers, and bag barriers filled with various filtering media placed around catch basins can be effective when the drainage area is 1 acre or less and flows do not exceed 0.5 cfs. It is necessary to allow for overtopping to prevent flooding. Many manufacturers have various inlet protection filters that are very effective in keeping sediment-laden water from entering the storm drainage system. The following are examples of a few common methods. a) Block and gravel filters (Figure D.2.1.5.G) are a barrier formed around an inlet with standard concrete block and gravel, installed as follows: • Height is 1 to 2 feet above the inlet. • Recess the first row of blocks 2 inches into the ground for stability. • Support subsequent rows by placing a 2x4 through the concrete block opening. • Do not use mortar. • Lay some blocks in the bottom row on their side for dewatering the pooled water. • Place cloth or mesh with ½ inch openings over all block openings. • Place gravel below the top of blocks on slopes of 2:1 or flatter. • An alternate design is a gravel donut. b) Gravel and wire mesh filters consist of a gravel barrier placed over the top of an inlet. This structure generally does not provide overflow. Install as follows: • Cloth or comparable wire mesh with ½ inch openings is placed over inlet. • Coarse aggregate covers the cloth or mesh. • Height/depth of gravel should be 1 foot or more, 18 inches wider than inlet on all sides. c) Curb inlet protection with a wooden weir is a barrier formed around an inlet with a wooden frame and gravel, installed as follows: • Construct a frame and attach wire mesh (½ inch openings) and filter fabric to the frame. • Pile coarse washed aggregate against the wire/fabric. • Place weight on frame anchors. d) Curb and gutter sediment barriers (Figure D.2.1.5.H) consist of sandbags or rock berms (riprap and aggregate) 3 feet high and 3 feet wide in a horseshoe shape, installed as follows: • Bags of either burlap or woven geotextile fabric, filled with a variety of media such as gravel, wood chips, compost or sand stacked tightly allows water to pond and allows sediment to separate from runoff. 4/24/2016 2016 Surface Water Design Manual – Appendix D D-54 D.2.1.5 SEDIMENT RETENTION • Leave a "one bag gap" in the top row of the barrier to provide a spillway for overflow. • Construct a horseshoe shaped berm, faced with coarse aggregate if using riprap, 3 x 3 and at least 2 feet from the inlet. • Construct a horseshoe shaped sedimentation trap on the outside of the berm to sediment trap standards for protecting a culvert inlet. 4. Excavated drop inlet sediment traps are appropriate where relatively heavy flows are expected and overflow capability is needed. If emergency overflow is provided, additional end-of-pipe treatment may be required. Excavated drop inlets consist of an excavated impoundment area around a storm drain. Sediment settles out of the stormwater prior to enter the drain. Install according to the following specifications: a) The impoundment area should have a depth of 1 - 2 feet measured from the crest of the inlet structure. b) Side slopes of the excavated area must be no steeper than 2:1. c) Minimum volume of the excavated area should be 35 cubic yards. d) Install provisions for draining the area to prevent standing water problems. e) Keep the area clear of debris. f) Weep holes may be drilled into the side of the inlet. g) Protect weep holes with wire mesh and washed aggregate. h) Weep holes must be sealed when removing and stabilizing excavated area. i) A temporary dike may be necessary on the down slope side of the structure to prevent bypass flow. Maintenance Standards 1. Any accumulated sediment on or around inlet protection shall be removed immediately. Sediment shall not be removed with water, and all sediment must be disposed of as fill on site or hauled off site. 2. Any sediment in the catch basin insert shall be removed when the sediment has filled one-third of the available storage. The filter media for the insert shall be cleaned or replaced at least monthly. 3. Regular maintenance is critical for all forms of catch basin/inlet protection. Unlike many forms of protection that fail gradually, catch basin protection will fail suddenly and completely if not maintained properly. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-55 SECTION D.2.1 ESC MEASURES FIGURE D.2.1.5.E FILTER FABRIC PROTECTION FIGURE D.2.1.5.F CATCH BASIN INSERT CATCH BASIN NOTE: ONLY TO BE USED WHERE PONDING OF WATER ABOVE THE CATCH BASIN WILL NOT CAUSE TRAFFIC PROBLEMS AND WHERE OVERFLOW WILL NOT RESULT IN EROSION OF SLOPES. GRATESTANDARD STRENGTH FILTER FABRIC NOTE: THIS DETAIL IS ONLY SCHEMATIC. ANY INSERT IS ALLOWED THAT HAS: •A MIN. 0.5 C.F. OF STORAGE, •THE MEANS TO DEWATER THE STORED SEDIMENT, •AN OVERFLOW, AND •CAN BE EASILY MAINTAINED. OVERFLOW GRATECATCH BASIN POROUS BOTTOM SOLID WALLS FILTER MEDIA FOR DEWATERING 4/24/2016 2016 Surface Water Design Manual – Appendix D D-56 D.2.1.5 SEDIMENT RETENTION FIGURE D.2.1.5.G BLOCK AND GRAVEL CURB INLET PROTECTION 1.USE BLOCK AND GRAVEL TYPE SEDIMENT BARRIER WHEN CURB INLET IS LOCATED IN GENTLY SLOPING SEGMENT, WHERE WATER CAN POND AND ALLOW SEDIMENT TO SEPARATE FROM RUNOFF. 2.BARRIER SHALL ALLOW FOR OVERFLOW FROM SEVERE STORM EVENT. 3.INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENT AND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. 2x4 WOOD STUD OVERFLOW WATER A A PLAN VIEW NTS SECTION A-A NTS BLOCK AND GRAVEL CURB INLET PROTECTION NTS CATCH BASIN COVER CURB INLET CONCRETE BLOCKS CATCH BASIN COVER CURB INLET CATCH BASIN BACK OF SIDEWALK CURB FACE 3/4" DRAIN GRAVEL (20 mm) WIRE SCREEN OR FILTER FABRIC POND HEIGHT WIRE SCREEN OR FILTER FABRIC 2x4 WOOD STUD (100x50 TIMBER STUD) 3/4" DRAIN GRAVEL (20 mm) NOTES: 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-57 SECTION D.2.1 ESC MEASURES FIGURE D.2.1.5.H CURB AND GUTTER BARRIER PROTECTION RUNOFF RUNOFF SPILLWAY 1.PLACE CURB-TYPE SEDIMENT BARRIERS ON GENTLY SLOPING STREET SEGMENTS, WHERE WATER CAN POND AND ALLOW SEDIMENT TO SEPARATE FROM RUNOFF. 2.SANDBAGS OF EITHER BURLAP OR WOVEN GEOTEXTILE FABRIC ARE FILLED WITH GRAVEL, LAYERED AND PACKED TIGHTLY. 3.LEAVE A ONE-SANDBAG GAP IN THE TOP ROW TO PROVIDE A SPILLWAY FOR OVERFLOW. 4.INSPECT BARRIERS AND REMOVE SEDIMENT AFTER EACH STORM EVENT. SEDIMENT AND GRAVEL MUST BE REMOVED FROM THE TRAVELED WAY IMMEDIATELY. GRAVEL FILLED SANDBAGS STACKED TIGHTLY DRAIN GRATE GUTTER CURB FACE CURB INLET SANDBAGS TO OVERLAP ONTO CURB BACK OF SIDEWALK PLAN VIEW NTS CURB AND GUTTER BARRIER NTS NOTES: 4/24/2016 2016 Surface Water Design Manual – Appendix D D-58 D.2.1.8 DUST CONTROL D.2.1.8 DUST CONTROL Preventative measures to minimize the wind transport of soil shall be taken when a traffic hazard may be created or when sediment transported by wind is likely to be deposited in water resources or adjacent properties. Purpose: To prevent wind transport of dust from exposed soil surfaces onto roadways, drainage ways, and surface waters. When to Install: Dust control shall be implemented when exposed soils are dry to the point that wind transport is possible and roadways, drainage ways, or surface waters are likely to be impacted. Dust control measures may consist of chemical, structural, or mechanical methods. Measures to Install: Water is the most common dust control (or palliative) used in the area. When using water for dust control, the exposed soils shall be sprayed until wet, but runoff shall not be generated by spraying. Calcium chloride, Magnesium chloride, Lignin derivatives, Tree Resin Emulsions, and Synthetic Polymer Emulsions may also be used for dust control. Exposed areas shall be re-sprayed as needed. Oil shall not be used for dust control. The following table lists many common dust control measures. Some of the measures are not recommended for use in King County and must have prior approval prior to use from the DPER inspector assigned to specific projects. 2016 Surface Water Design Manual – Appendix D 4/24/2016 D-69 SECTION D.2.1 ESC MEASURES TABLE D.2.1.8.A DUST CONTROL MEASURES METHOD CONSIDERATIONS SITE PREPARATION RECOMMENDED APPLICATION RATE Water -Most commonly used practice -Evaporates quickly -Lasts less than 1 day For all liquid agents: -Blade a small surface -Crown or slope surface to avoid ponding -Compact soils if needed -Uniformly pre-wet at 0.03 – 0.3 gal/sq yd -Apply solution under pressure. Overlap solution 6 – 12 inches -Allow treated area to cure 0 – 4 hours -Compact area after curing -Apply second treatment before first treatment becomes ineffective 0.125 gal/sq yd every 20 to 30 minutes Salts Calcium Chloride (CaCl) -Restricts evaporation -Lasts 6-12 months -Can be corrosive -Less effective in low humidity -Can build up in soils and leach by rain Apply 38% solution at 1.21L/m2 (0.27 gal/yd2) or as loose dry granules per manufacturer Magnesium Chloride (MgCl) -Restricts evaporation -Works at higher temperatures and lower humidity than CaCl -May be more costly than CaCl Apply 26 – 32% solution at 2.3 L/m2 (0.5 gal/yd2) Sodium Chloride (NaCl) -Effective over smaller range of conditions -Less expensive -Can be corrosive -Less effective in low humidity Per Manufacturer Silicates -Generally expensive -Available in small quantities -Require Second application Surfactants -High evaporation rates -Effective for short time periods -Must apply frequently Copolymers -Forms semi-permeable transparent crust -Resists ultraviolet radiation and moisture induced breakdown -Last 1 to 2 years 750 – 940 L/ha (80 – 100 gal/ac) Petroleum Products -Used oil is prohibited as a dust control method -Bind soil particles -May hinder foliage growth -Environmental and aesthetic concerns -Higher cost Use 57 – 63% resins as base. Apply at 750 – 940 L/ha (80-100 gal/ac) Lignin Sulfonate -Paper industry waste product -Acts as dispersing agent -Best in dry climates -Can be slippery -Will decrease Dissolved Oxygen in waterways therefore cannot be used adjacent to surface water systems Loosen surface 25-50 mm (1 – 2 inches) Need 4-8% fines Vegetable Oils -Coat grains of soils, so limited binding ability -May become brittle -Limited availability Per Manufacturer Spray on Adhesives -Available as organic or synthetic -Effective on dry, hard soils -Forms a crust -Can last 3 to 4 years Per Manufacturer 4/24/2016 2016 Surface Water Design Manual – Appendix D D-70 P a g e | 31 C. Correspondence P a g e | 32 D. Site Inspection Form Project Name Permit # Inspection Date Time Name of Certified Erosion Sediment Control Lead (CESCL) or qualified inspector if less than one acre Print Name: Approximate rainfall amount since the last inspection (in inches): Approximate rainfall amount in the last 24 hours (in inches): Current Weather Clear Cloudy Mist Rain Wind Fog A. Type of inspection: Weekly Post Storm Event Other B. Phase of Active Construction (check all that apply): Pre Construction/installation of erosion/sediment controls Clearing/Demo/Grading Infrastructure/storm/roads Concrete pours Vertical Construction/buildings Utilities Offsite improvements Site temporary stabilized Final stabilization C. Questions: 1. Were all areas of construction and discharge points inspected? Yes No 2. Did you observe the presence of suspended sediment, turbidity, discoloration, or oil sheen Yes No 3. Was a water quality sample taken during inspection? (refer to permit conditions S4 & S5) Yes No 4. Was there a turbid discharge 250 NTU or greater, or Transparency 6 cm or less?* Yes No 5. If yes to #4 was it reported to Ecology? Yes No 6. Is pH sampling required? pH range required is 6.5 to 8.5. Yes No If answering yes to a discharge, describe the event. Include when, where, and why it happened; what action was taken, and when. *If answering yes to # 4 record NTU/Transparency with continual sampling daily until turbidity is 25 NTU or less/ transparenc y is 33 cm or greater. Sampling Results: Date: Parameter Method (circle one) Result Other/Note NTU cm pH Turbidity tube, meter, laboratory pH Paper, kit, meter P a g e | 33 D. Check the observed status of all items. Provide “Action Required “details and dates. Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 1 Clearing Limits Before beginning land disturbing activities are all clearing limits, natural resource areas (streams, wetlands, buffers, trees) protected with barriers or similar BMPs? (high visibility recommended) 2 Construction Access Construction access is stabilized with quarry spalls or equivalent BMP to prevent sediment from being tracked onto roads? Sediment tracked onto the road way was cleaned thoroughly at the end of the day or more frequent as necessary. 3 Control Flow Rates Are flow control measures installed to control stormwater volumes and velocity during construction and do they protect downstream properties and waterways from erosion? If permanent infiltration ponds are used for flow control during construction, are they protected from siltation? 4 Sediment Controls All perimeter sediment controls (e.g. silt fence, wattles, compost socks, berms, etc.) installed, and maintained in accordance with the Stormwater Pollution Prevention Plan (SWPPP). Sediment control BMPs (sediment ponds, traps, filters etc.) have been constructed and functional as the first step of grading. Stormwater runoff from disturbed areas is directed to sediment removal BMP. 5 Stabilize Soils Have exposed un-worked soils been stabilized with effective BMP to prevent erosion and sediment deposition? P a g e | 34 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 5 Stabilize Soils Cont. Are stockpiles stabilized from erosion, protected with sediment trapping measures and located away from drain inlet, waterways, and drainage channels? Have soils been stabilized at the end of the shift, before a holiday or weekend if needed based on the weather forecast? 6 Protect Slopes Has stormwater and ground water been diverted away from slopes and disturbed areas with interceptor dikes, pipes and or swales? Is off-site storm water managed separately from stormwater generated on the site? Is excavated material placed on uphill side of trenches consistent with safety and space considerations? Have check dams been placed at regular intervals within constructed channels that are cut down a slope? 7 Drain Inlets Storm drain inlets made operable during construction are protected. Are existing storm drains within the influence of the project protected? 8 Stabilize Channel and Outlets Have all on-site conveyance channels been designed, constructed and stabilized to prevent erosion from expected peak flows? Is stabilization, including armoring material, adequate to prevent erosion of outlets, adjacent stream banks, slopes and downstream conveyance systems? 9 Control Pollutants Are waste materials and demolition debris handled and disposed of to prevent contamination of stormwater? Has cover been provided for all chemicals, liquid products, petroleum products, and other material? Has secondary containment been provided capable of containing 110% of the volume? Were contaminated surfaces cleaned immediately after a spill incident? Were BMPs used to prevent contamination of stormwater by a pH modifying sources? P a g e | 35 Element # Inspection BMPs Inspected BMP needs maintenance BMP failed Action required (describe in section F) yes no n/a 9 Cont. Wheel wash wastewater is handled and disposed of properly. 10 Control Dewatering Concrete washout in designated areas. No washout or excess concrete on the ground. Dewatering has been done to an approved source and in compliance with the SWPPP. Were there any clean non turbid dewatering discharges? 11 Maintain BMP Are all temporary and permanent erosion and sediment control BMPs maintained to perform as intended? 12 Manage the Project Has the project been phased to the maximum degree practicable? Has regular inspection, monitoring and maintenance been performed as required by the permit? Has the SWPPP been updated, implemented and records maintained? 13 Protect LID Is all Bioretention and Rain Garden Facilities protected from sedimentation with appropriate BMPs? Is the Bioretention and Rain Garden protected against over compaction of construction equipment and foot traffic to retain its infiltration capabilities? Permeable pavements are clean and free of sediment and sediment laden- water runoff. Muddy construction equipment has not been on the base material or pavement. Have soiled permeable pavements been cleaned of sediments and pass infiltration test as required by stormwater manual methodology? Heavy equipment has been kept off existing soils under LID facilities to retain infiltration rate. E. Check all areas that have been inspected. All in place BMPs All disturbed soils All concrete wash out area All material storage areas All discharge locations All equipment storage areas All construction entrances/exits P a g e | 36 F. Elements checked “Action Required” (section D) describe corrective action to be taken. List the element number; be specific on location and work needed. Document, initial, and date when the corrective action has been completed and inspected. Element # Description and Location Action Required Completion Date Initials Attach additional page if needed Sign the following certification: “I certify that this report is true, accurate, and complete, to the best of my knowledge and belief” Inspected by: (print) (Signature) Date: Title/Qualification of Inspector: P a g e | 37 E. Construction Stormwater General Permit (CSWGP) P a g e | 38 F. 303(d) List Waterbodies / TMDL Waterbodies Information Listing ID: 12193 Main Listing Information Listing ID: 12193 2014 Category: 5 Waterbody Name: WASHINGTON LAKE 2012 Category: 5 Medium: Water 2008 Category: 5 Parameter: Bacteria 2004 Category: 5 WQI Project: None Assigned On 1998 303(d) List?: Y Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 47122F2A0 Location Identification Counties: King Waterbody ID (WBID): WA-08-9350 Town/Range/Section (Legacy): None Assigned WRIA: 8 - Cedar-Sammamish Waterbody Class: LAK Basis King County unpublished data from station 0828SB show a geometric mean of 220 cfu/100mL with 53% exceeding the percentile criterion during 1998. King County unpublished data from station 0828SB show a geometric mean of 82 cfu/100mL with 35% exceeding the percentile criterion during 1999. King County unpublished data from station 0828SB show a geometric mean of 94 cfu/100mL with 56% exceeding the percentile criterion during 2000. King County unpublished data from station 0828SB show a geometric mean of 31 cfu/100mL with 20% exceeding the percentile criterion during 2001. King County unpublished data from station 0828SB show a geometric mean of 105 cfu/100mL with 50% exceeding the percentile criterion during 2002. Remarks No Remarks Entered EIM No EIM Records Entered Page 1 of 1Print Approved Listing 5/22/2019https://apps.ecology.wa.gov/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=12193 Listing ID: 52853 Main Listing Information Listing ID: 52853 2014 Category: 5 Waterbody Name: WASHINGTON LAKE 2012 Category: 5 Medium: Water 2008 Category: 5 Parameter: Total Phosphorus 2004 Category: 3 WQI Project: None Assigned On 1998 303(d) List?: N Designated Use: None Assigned On 1996 303(d) List?: N Assessment Unit Assessment Unit ID: 47122H2E6 Location Identification Counties: King Waterbody ID (WBID): None Assigned Town/Range/Section (Legacy): None Assigned WRIA: 8 - Cedar-Sammamish Waterbody Class: LAK Basis Location ID [KCM-0804] -- In 2004 the summer epilimnetic mean concentration of total phosphorus samples did not exceed the action value for this ecoregion (20 ug/L). Location ID [KCM-0804] -- In 2005 the summer epilimnetic mean concentration of total phosphorus samples did not exceed the action value for this ecoregion (20 ug/L). Location ID [KCM-0804] -- In 2006 the summer epilimnetic mean concentration of total phosphorus samples exceeded the action value for this ecoregion (20 ug/L). Remarks No Remarks Entered EIM User Study ID:User Location ID: KClake-1 KCM-0804 KClake-1 KCM-0804 Page 1 of 1Print Approved Listing 5/22/2019https://apps.ecology.wa.gov/approvedwqa/ApprovedPrintListing.aspx?LISTING_ID=52853 P a g e | 39 G. Contaminated Site Information P a g e | 40 H. Engineering Calculations Appendix B WWHM Report WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Apron E - Flow Rate_2019-11-26 Site Name: Site Address: City : Report Date: 11/26/2019 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2018/10/10 Version : 4.2.16 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : On-site Basin Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat 1 Pervious Total 1 Impervious Land Use acre ROADS FLAT 8.53 ROOF TOPS FLAT 0.3 Impervious Total 8.83 Basin Total 9.83 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : On-site Basin Bypass: No GroundWater: No Pervious Land Use acre C, Lawn, Flat .72 Pervious Total 0.72 Impervious Land Use acre ROADS FLAT 7.46 ROOF TOPS FLAT 1.64 Impervious Total 9.1 Basin Total 9.82 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:1 Total Impervious Area:8.83 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0.72 Total Impervious Area:9.1 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 3.430806 5 year 4.355272 10 year 4.98581 25 year 5.806189 50 year 6.435757 100 year 7.081958 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 3.515847 5 year 4.45636 10 year 5.097084 25 year 5.92994 50 year 6.56856 100 year 7.223634 ___________________________________________________________________ WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Boeing Apron E WQ Treatment - North Site Name: Boeing Apron E Site Address: City : Renton Report Date: 6/13/2019 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2017/04/14 Version : 4.2.13 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 3.43 Pervious Total 3.43 Impervious Land Use acre Impervious Total 0 Basin Total 3.43 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre PARKING FLAT 3.43 Impervious Total 3.43 Basin Total 3.43 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:3.43 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:3.43 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.100845 5 year 0.158381 10 year 0.190987 25 year 0.225531 50 year 0.246907 100 year 0.265088 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.307737 5 year 1.651824 10 year 1.885607 25 year 2.188858 50 year 2.420958 100 year 2.658694 ___________________________________________________________________ ___________________________________________________________________ Water Quality BMP Flow and Volume for POC #1 On-line facility volume: 0.4218 acre-feet On-line facility target flow: 0.557 cfs. Adjusted for 15 min: 0.557 cfs. Off-line facility target flow: 0.3148 cfs. = 141.3 gpm Adjusted for 15 min: 0.3148 cfs. ___________________________________________________________________ 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. 2005-2019; All Rights Reserved. WWHM2012 PROJECT REPORT ___________________________________________________________________ Project Name: Boeing Apron E WQ Treatment - South_2019-11-26 Site Name: Boeing Apron A Site Address: City : Renton Report Date: 11/26/2019 Gage : Seatac Data Start : 1948/10/01 Data End : 2009/09/30 Precip Scale: 1.00 Version Date: 2018/10/10 Version : 4.2.16 ___________________________________________________________________ Low Flow Threshold for POC 1 : 50 Percent of the 2 Year ___________________________________________________________________ High Flow Threshold for POC 1: 50 year ___________________________________________________________________ PREDEVELOPED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre C, Forest, Flat 4.96 Pervious Total 4.96 Impervious Land Use acre Impervious Total 0 Basin Total 4.96 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ MITIGATED LAND USE Name : Basin 1 Bypass: No GroundWater: No Pervious Land Use acre Pervious Total 0 Impervious Land Use acre PARKING FLAT 4.96 Impervious Total 4.96 Basin Total 4.96 ___________________________________________________________________ Element Flows To: Surface Interflow Groundwater ___________________________________________________________________ ___________________________________________________________________ ANALYSIS RESULTS Stream Protection Duration ___________________________________________________________________ Predeveloped Landuse Totals for POC #1 Total Pervious Area:4.96 Total Impervious Area:0 ___________________________________________________________________ Mitigated Landuse Totals for POC #1 Total Pervious Area:0 Total Impervious Area:4.96 ___________________________________________________________________ Flow Frequency Return Periods for Predeveloped. POC #1 Return Period Flow(cfs) 2 year 0.145828 5 year 0.229029 10 year 0.27618 25 year 0.326133 50 year 0.357043 100 year 0.383335 Flow Frequency Return Periods for Mitigated. POC #1 Return Period Flow(cfs) 2 year 1.891072 5 year 2.388644 10 year 2.72671 25 year 3.165231 50 year 3.500863 100 year 3.844645 ___________________________________________________________________ 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: 0.61 acre-feet On-line facility target flow: 0.8056 cfs. Adjusted for 15 min: 0.8056 cfs. Off-line facility target flow: 0.4553 cfs. = 204.35 gpm Adjusted for 15 min: 0.4553 cfs. ___________________________________________________________________ LID Report LID Technique Used for Total Volume Volume Infiltration Cumulative Percent Water Quality Percent Comment Treatment? Needs Through Volume Volume Volume Water Quality Treatment Facility (ac-ft.) Infiltration Infiltrated Treated (ac-ft) (ac-ft) Credit Total Volume Infiltrated 0.00 0.00 0.00 0.00 0.00 0% No Treat. Credit Compliance with LID Standard 8 Duration Analysis Result = Failed ___________________________________________________________________ Perlnd and Implnd Changes No changes have been made. ___________________________________________________________________ This program and accompanying documentation are provided 'as-is' without warranty of any kind. The entire risk regarding the performance and results of this program is assumed by End User. Clear Creek Solutions Inc. and the governmental licensee or sublicensees disclaim all warranties, either expressed or implied, including but not limited to implied warranties of program and accompanying documentation. In no event shall Clear Creek Solutions Inc. be liable for any damages whatsoever (including without limitation to damages for loss of business profits, loss of business information, business interruption, and the like) arising out of the use of, or inability to use this program even if Clear Creek Solutions Inc. or their authorized representatives have been advised of the possibility of such damages. Software Copyright © by : Clear Creek Solutions, Inc. 2005-2019; All Rights Reserved. Appendix C Water Quality Treatment Standard Detail Appendix D Conveyance and Backwater Analysis Calculations Appendix D.1 25 Year Conveyance Calculations Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Appendix D.2 100 Year Lake Washington Backwater Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Appendix D.3 100 Year North System Backwater Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Appendix D.4 100 Year South System Backwater Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Autodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary AnalysisAutodesk Storm and Sanitary Analysis Appendix E Stormwater Drainage Plans and Details 17 13 11 11 12 12 12 3 17 19 19 19 19 14 17 12 RENTON SITE STORM DRAINAGE PLAN C295 C24 90% DESIGN REVIEW NOT FOR CONSTRUCTION 3 11 12 13 14 17 19 19 RENTON SITE STORM DRAINAGE PLAN C296 C25 90% DESIGN REVIEW NOT FOR CONSTRUCTION 19 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C307 C28 3 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C308 C29 19 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C310 C30 11 17 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C311 C31 12 13 14 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C312 C32 15 16 20 23 A D E 16 11 15 13 17 13 14 12 12 20 C B 20 1214 23 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE ENLARGED STORM DRAIN PLAN C450 C33 11 13 14 15 A B C D 16 17 12 E 20 23 BB CC A A D D 19 20 21 20 19 18 22 13 8 11 152 5 11 9 11 7 8 1010 11 6 10 99 22 13 12 12 26 10 1 5 3 3 28 3 3 3 77 9 7 99 1515 25 16 27 29 30 7 18 2424 15 17 15 31 31 10 10 31 33 9 10 11 6 6 6 10 22 22 1 2 5 5 66 9 7 7 7 9 9 9 9 14 30 14 20 21 20 1016 10811 18 19 13 19 18 2419 17 1111 1414 2323 29 15 28 4 12 1919 1 2 3 3 5 6 9 1515 9 14 23 17 13 22 18 14 13 22 18 14 23 6 11 11 11 77 29 12 12 4 RENTON SITE FLOW DIVERSION VAULT DETAILS C503A C40 90% DESIGN REVIEW NOT FOR CONSTRUCTION # ” 2 1 1 3 3 4 4 5 5 6666 7 27 24 22 18 15 24 22 18 26 9 9 10 17 17 8 13 22 18 13 22 1814 14 2323 2323 14 14 14 16 1515 3 3 11 11 11 1111 25 121212 28 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE FLOW DIVERSION VAULT DETAILS C504A C41 # ” AA 2 7 1112 15 181842022 24 9 8 13 3 4 15 18184202212 13 15 19 28 25 17 4 10 1112 10 13 30 4 4 23 18 4 1 2 5 6 8 7 9 10 11 12 14 13 4 15 18181719 2121 2022 4 25 4 24 1615 16 27 29 6 3030 3 4 11 4 4 1815 13 26 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE LIFT STATION DETAILS C505A C42 · · · · · · RENTON SITE SLOT DRAIN DETAILS C507A C43 90% DESIGN REVIEW NOT FOR CONSTRUCTION Size per plan NOTE: S+B=6", EXCEPT FOR THE DURASLOT DRAINS THAT ARE AIRPLANE RATED AIRPLANE RATED STRUCTURAL FOUNDATION (ALUMINUM) 1/2 #13 304 STAINLESS STEEL EXPANDED METAL GRATING FLOATS BRACKET MOUNTING 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE OIL-WATER SEPARATOR DETAILS C508A C44 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE OIL WATER SEPARATOR DETAILS C509A C45 SECTION AA A PLAN VIEW A END VIEW 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE MISC STORM DRAINAGE VAULT DETAILS C510A C46 RENTON SITE STORM DRAINAGE DETAILS C512A C48 90% DESIGN REVIEW NOT FOR CONSTRUCTION SKYDROL DRAINS CATCH BASIN NNN STALL NNN VALVE DISC POSITIONS VAULTNo. 504-LA COVER SAFE DRAIN SECTION AA A PLAN VIEW A END VIEW 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE DETAILS C513A C49 · · · · · · · · · · 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE DETAILS C514A C50 RENTON SITE STORM DRAINAGE DETAILS C515A C51 90% DESIGN REVIEW NOT FOR CONSTRUCTION VaultNo.InsideWidth InsideLength OutsideLength Base WeighNo. Riser WeightNo. BASE Top WeightNo. TOP RISER RISER OPTIONAL TOPS AVAILABLE VARIABLE SIZE CHART 620-LA-10 818-LA-10 1020-LA-10 1024-LA-10 1022-LA-10 OPTIONAL RISER HEIGHT: 3'-0", 3'-6", 4'-0" & 5'-0" oldcastleprecast.com/wilsonville Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 SECTIONAL VAULT 2011 020UCP-LG-SECTIONAL1 SECTIONAL VAULT - SIZE AS REQUIRED -POWER / WATER / GAS LARGE SECTIONAL VAULT OutsideWidth 620-LA818-LA1020-LA1022-LA1024-LA* A PLAN VIEW SECTION AA A END VIEW VaultNo.C D E F RISER JOINT DETAIL 620-LA-10 A B 818-LA-10 1020-LA-10 1022-LA-10 1024-LA-10 VARIABLE SIZE CHART RENTON SITE STORM DRAINAGE DETAILS C516A C52 90% DESIGN REVIEW NOT FOR CONSTRUCTION 4", 6" & OPTIONAL TOP TOPNo. 816-7-T-42EE (Shown) BASENo. 816-B oldcastleprecast.com/wilsonville Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 816-LA 2016 020-816LA 816-LA 8 x 16POWER / WATER / GAS 816-LA 31.0 A PLAN VIEW SECTION AA A END VIEW Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 oldcastleprecast.com/wilsonville 816-LA 2016 020-816LA 816-LA 8 x 16POWER / WATER / GAS 816-LA 31.1 90% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE FUEL CONTAINMENT VAULT DETAILS C517A C53 RENTON SITE DE-ICING FUEL SPILL DIAGRAM C518 C54 90% DESIGN REVIEW NOT FOR CONSTRUCTION FM FM BOEING 737-MAX10BOEING 737-MAX1017 73 10 21 17 66 8 8 4 55 9 7 9 RENTON SITE STORM DRAINAGE PLAN C297 C26 60% DESIGN REVIEW NOT FOR CONSTRUCTION 3 4 5 9 6 7 8 10 17 18 21 BOEING 737-MAX106 5 5 21 2 5 5 6 22 RENTON SITE STORM DRAINAGE PLAN C298 C27 60% DESIGN REVIEW NOT FOR CONSTRUCTION 2 5 6 21 22 1 1 RENTON SITE STORM DRAINAGE PLAN C299 C28 60% DESIGN REVIEW NOT FOR CONSTRUCTION 1 1 2 RENTON SITE STORM DRAINAGE PLAN C300 C29 60% DESIGN REVIEW NOT FOR CONSTRUCTION 1 2 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C307 C31 1 2 3 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C308 C32 4 5 9 10 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C309 C33 6 7 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C310 C34 8 17 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE PROFILES C312 C35 18 21 22 18 17 17 7 7 17 7 17 21 7 18 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE ENLARGED STORM DRAIN PLAN C451 C36 7 18 17 21 AA 2 7 1112 15 181842022 4 24 9 8 18 3 4 15 18184202212 18 23 19 28 25 17 4 10 1112 10 3 18 30 4 15 1 2 5 6 3 8 7 9 10 11 12 4 14 13 4 15 1818 17 19 2121 2022 4 25 4 24 1615 16 27 29 6 3030 4 4 4 15 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE LIFT STATION DETAILS C506B C46 · · · · · · RENTON SITE SLOT DRAIN DETAILS C507B C47 60% DESIGN REVIEW NOT FOR CONSTRUCTION Size per plan NOTE: S+B=6", EXCEPT FOR THE DURASLOT DRAINS THAT ARE AIRPLANE RATED AIRPLANE RATED STRUCTURAL FOUNDATION (ALUMINUM) 1/2 #13 304 STAINLESS STEEL EXPANDED METAL GRATING FLOATS BRACKET MOUNTING 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE OIL-WATER SEPARATOR DETAILS C508B C48 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE FLOW SPLITTER - DIVERSION VALVE DETAILS C509B C49 SECTION AA A PLAN VIEW A END VIEW 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE MISC STORM DRAINAGE VAULT DETAILS C510B C50 RENTON SITE STORM DRAINAGE DETAILS C512B C52 60% DESIGN REVIEW NOT FOR CONSTRUCTION SKYDROL DRAINS CATCH BASIN NNN STALL NNN VALVE DISC POSITIONS VAULTNo. 504-LA COVER SAFE DRAIN SECTION AA A PLAN VIEW A END VIEW 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE DETAILS C513B C53 · · · · · · · · · · 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE STORM DRAINAGE DETAILS C514B C54 RENTON SITE STORM DRAINAGE DETAILS C515B C55 60% DESIGN REVIEW NOT FOR CONSTRUCTION VaultNo.InsideWidth InsideLength OutsideLength Base WeighNo. Riser WeightNo. BASE Top WeightNo. TOP RISER RISER OPTIONAL TOPS AVAILABLE VARIABLE SIZE CHART 620-LA-10 818-LA-10 1020-LA-10 1024-LA-10 1022-LA-10 OPTIONAL RISER HEIGHT: 3'-0", 3'-6", 4'-0" & 5'-0" oldcastleprecast.com/wilsonville Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 SECTIONAL VAULT 2011 020UCP-LG-SECTIONAL1 SECTIONAL VAULT - SIZE AS REQUIRED -POWER / WATER / GAS LARGE SECTIONAL VAULT OutsideWidth 620-LA818-LA1020-LA1022-LA1024-LA* A PLAN VIEW SECTION AA A END VIEW VaultNo.C D E F RISER JOINT DETAIL 620-LA-10 A B 818-LA-10 1020-LA-10 1022-LA-10 1024-LA-10 VARIABLE SIZE CHART RENTON SITE STORM DRAINAGE DETAILS C516B C56 60% DESIGN REVIEW NOT FOR CONSTRUCTION 4", 6" & OPTIONAL TOP TOPNo. 816-7-T-42EE (Shown) BASENo. 816-B oldcastleprecast.com/wilsonville Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 816-LA 2016 020-816LA 816-LA 8 x 16POWER / WATER / GAS 816-LA 31.0 A PLAN VIEW SECTION AA A END VIEW Issue Date: File Name: PO Box 323, Wilsonville, Oregon 97070-0323 Tel: (503) 682-2844 Fax: (503) 682-2657 oldcastleprecast.com/wilsonville 816-LA 2016 020-816LA 816-LA 8 x 16POWER / WATER / GAS 816-LA 31.1 60% DESIGN REVIEW NOT FOR CONSTRUCTION RENTON SITE FUEL CONTAINMENT VAULT DETAILS C517B C57 RENTON SITE NIC_DE-ICING FUEL SPILL DIAGRAM C519 C58 60% DESIGN REVIEW NOT FOR CONSTRUCTION Appendix F City of Renton Bond Quantity Worksheet Planning Division |1055 South Grady Way – 6 th Floor | Renton, WA 98057 (425) 430-7200 Date Prepared: Name: PE Registration No: Firm Name: Firm Address: Phone No. Email Address: Project Name: Project Owner: CED Plan # (LUA):Phone: CED Permit # (U):Address: Site Address: Street Intersection:Addt'l Project Owner: Parcel #(s):Phone: Address: Clearing and grading greater than or equal to 5,000 board feet of timber? Yes/No:NO Water Service Provided by: If Yes, Provide Forest Practice Permit #:Sewer Service Provided by: SITE IMPROVEMENT BOND QUANTITY WORKSHEET PROJECT INFORMATION CITY OF RENTON KC WATER DISTRICT 90 1 Select the current project status/phase from the following options: For Approval - Preliminary Data Enclosed, pending approval from the City; For Construction - Estimated Data Enclosed, Plans have been approved for contruction by the City; Project Closeout - Final Costs and Quantities Enclosed for Project Close-out Submittal Phone Engineer Stamp Required (all cost estimates must have original wet stamp and signature) Clearing and Grading Utility Providers N/A Project Location and Description Project Owner Information Apron E - Stalls Phase 1 Renton, WA 98055 Parcel Number Boeing ##-######425-965-2421 12/6/2019 Prepared by: FOR APPROVALProject Phase 1 tneu@dowl.com Travis Neu 45379 DOWL 8410 154th Avenue NE, Suite 120 425-869-2670 419-471 Logan Ave N 737 Logan Ave N Additional Project OwnerN 6th St ######## AddressAbbreviated Legal Description: See Cover Sheet City, State, Zip Page 1 of 7 Ref 8-H Bond Quantity Worksheet SECTION I PROJECT INFORMATION Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 CED Permit #:######## Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost DRAINAGE (CPE = Corrugated Polyethylene Pipe, N12 or Equivalent) For Culvert prices, Average of 4' cover was assumed. Assume perforated PVC is same price as solid pipe.) Access Road, R/D D-1 26.00$ SY * (CBs include frame and lid) Beehive D-2 90.00$ Each Through-curb Inlet Framework D-3 400.00$ Each CB Type I D-4 1,500.00$ Each 10 15,000.00 CB Type IL D-5 1,750.00$ Each CB Type II, 48" diameter D-6 2,300.00$ Each 38 87,400.00 for additional depth over 4' D-7 480.00$ FT 270.47 129,825.60 CB Type II, 54" diameter D-8 2,500.00$ Each for additional depth over 4'D-9 495.00$ FT CB Type II, 60" diameter D-10 2,800.00$ Each 1 2,800.00 for additional depth over 4'D-11 600.00$ FT 8.57 5,142.00 CB Type II, 72" diameter D-12 6,000.00$ Each for additional depth over 4'D-13 850.00$ FT CB Type II, 96" diameter D-14 14,000.00$ Each for additional depth over 4'D-15 925.00$ FT Trash Rack, 12"D-16 350.00$ Each Trash Rack, 15"D-17 410.00$ Each Trash Rack, 18"D-18 480.00$ Each Trash Rack, 21"D-19 550.00$ Each Cleanout, PVC, 4"D-20 150.00$ Each Cleanout, PVC, 6"D-21 170.00$ Each Cleanout, PVC, 8"D-22 200.00$ Each Culvert, PVC, 4" D-23 10.00$ LF Culvert, PVC, 6" D-24 13.00$ LF Culvert, PVC, 8" D-25 15.00$ LF Culvert, PVC, 12" D-26 23.00$ LF Culvert, PVC, 15" D-27 35.00$ LF Culvert, PVC, 18" D-28 41.00$ LF Culvert, PVC, 24"D-29 56.00$ LF Culvert, PVC, 30" D-30 78.00$ LF Culvert, PVC, 36" D-31 130.00$ LF Culvert, CMP, 8"D-32 19.00$ LF Culvert, CMP, 12"D-33 29.00$ LF SUBTOTAL THIS PAGE:240,167.60 (B)(C)(D)(E) SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) Page 2 of 7 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 CED Permit #:######## Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) DRAINAGE (Continued) Culvert, CMP, 15"D-34 35.00$ LF Culvert, CMP, 18"D-35 41.00$ LF Culvert, CMP, 24"D-36 56.00$ LF Culvert, CMP, 30"D-37 78.00$ LF Culvert, CMP, 36"D-38 130.00$ LF Culvert, CMP, 48"D-39 190.00$ LF Culvert, CMP, 60"D-40 270.00$ LF Culvert, CMP, 72"D-41 350.00$ LF Culvert, Concrete, 8"D-42 42.00$ LF Culvert, Concrete, 12"D-43 48.00$ LF Culvert, Concrete, 15"D-44 78.00$ LF Culvert, Concrete, 18"D-45 48.00$ LF Culvert, Concrete, 24"D-46 78.00$ LF Culvert, Concrete, 30"D-47 125.00$ LF Culvert, Concrete, 36"D-48 150.00$ LF Culvert, Concrete, 42"D-49 175.00$ LF Culvert, Concrete, 48"D-50 205.00$ LF Culvert, CPE Triple Wall, 6" D-51 14.00$ LF Culvert, CPE Triple Wall, 8" D-52 16.00$ LF Culvert, CPE Triple Wall, 12" D-53 24.00$ LF Culvert, CPE Triple Wall, 15" D-54 35.00$ LF Culvert, CPE Triple Wall, 18" D-55 41.00$ LF Culvert, CPE Triple Wall, 24" D-56 56.00$ LF Culvert, CPE Triple Wall, 30" D-57 78.00$ LF Culvert, CPE Triple Wall, 36" D-58 130.00$ LF Culvert, LCPE, 6"D-59 60.00$ LF Culvert, LCPE, 8"D-60 72.00$ LF Culvert, LCPE, 12"D-61 84.00$ LF Culvert, LCPE, 15"D-62 96.00$ LF Culvert, LCPE, 18"D-63 108.00$ LF Culvert, LCPE, 24"D-64 120.00$ LF Culvert, LCPE, 30"D-65 132.00$ LF Culvert, LCPE, 36"D-66 144.00$ LF Culvert, LCPE, 48"D-67 156.00$ LF Culvert, LCPE, 54"D-68 168.00$ LF SUBTOTAL THIS PAGE: (B)(C)(D)(E) Page 3 of 7 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 CED Permit #:######## Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) DRAINAGE (Continued) Culvert, LCPE, 60"D-69 180.00$ LF Culvert, LCPE, 72"D-70 192.00$ LF Culvert, HDPE, 6"D-71 42.00$ LF 2759 115,878.00 Culvert, HDPE, 8"D-72 42.00$ LF 555 23,310.00 Culvert, HDPE, 12"D-73 74.00$ LF 3336 246,864.00 Culvert, HDPE, 15"D-74 106.00$ LF Culvert, HDPE, 18"D-75 138.00$ LF 576 79,488.00 Culvert, HDPE, 24"D-76 221.00$ LF 87 19,227.00 Culvert, HDPE, 30"D-77 276.00$ LF Culvert, HDPE, 36"D-78 331.00$ LF Culvert, HDPE, 48"D-79 386.00$ LF Culvert, HDPE, 54"D-80 441.00$ LF Culvert, HDPE, 60"D-81 496.00$ LF Culvert, HDPE, 72"D-82 551.00$ LF Pipe, Polypropylene, 6"D-83 84.00$ LF Pipe, Polypropylene, 8"D-84 89.00$ LF Pipe, Polypropylene, 12"D-85 95.00$ LF Pipe, Polypropylene, 15"D-86 100.00$ LF Pipe, Polypropylene, 18"D-87 106.00$ LF Pipe, Polypropylene, 24"D-88 111.00$ LF Pipe, Polypropylene, 30"D-89 119.00$ LF Pipe, Polypropylene, 36"D-90 154.00$ LF Pipe, Polypropylene, 48"D-91 226.00$ LF Pipe, Polypropylene, 54"D-92 332.00$ LF Pipe, Polypropylene, 60"D-93 439.00$ LF Pipe, Polypropylene, 72"D-94 545.00$ LF Culvert, DI, 6"D-95 61.00$ LF Culvert, DI, 8"D-96 84.00$ LF 29 2,436.00 Culvert, DI, 12"D-97 106.00$ LF 34 3,604.00 Culvert, DI, 15"D-98 129.00$ LF Culvert, DI, 18"D-99 152.00$ LF Culvert, DI, 24"D-100 175.00$ LF Culvert, DI, 30"D-101 198.00$ LF Culvert, DI, 36"D-102 220.00$ LF Culvert, DI, 48"D-103 243.00$ LF Culvert, DI, 54"D-104 266.00$ LF Culvert, DI, 60"D-105 289.00$ LF Culvert, DI, 72"D-106 311.00$ LF SUBTOTAL THIS PAGE:490,807.00 (B)(C)(D)(E) Page 4 of 7 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 CED Permit #:######## Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) Specialty Drainage Items Ditching SD-1 9.50$ CY Flow Dispersal Trench (1,436 base+)SD-3 28.00$ LF French Drain (3' depth)SD-4 26.00$ LF Geotextile, laid in trench, polypropylene SD-5 3.00$ SY Mid-tank Access Riser, 48" dia, 6' deep SD-6 2,000.00$ Each Pond Overflow Spillway SD-7 16.00$ SY Restrictor/Oil Separator, 12"SD-8 1,150.00$ Each Restrictor/Oil Separator, 15"SD-9 1,350.00$ Each Restrictor/Oil Separator, 18"SD-10 1,700.00$ Each Riprap, placed SD-11 42.00$ CY Tank End Reducer (36" diameter)SD-12 1,200.00$ Each Infiltration pond testing SD-13 125.00$ HR Permeable Pavement SD-14 Permeable Concrete Sidewalk SD-15 Culvert, Box __ ft x __ ft SD-16 SUBTOTAL SPECIALTY DRAINAGE ITEMS: (B)(C)(D)(E) STORMWATER FACILITIES (Include Flow Control and Water Quality Facility Summary Sheet and Sketch) Detention Pond SF-1 Each Detention Tank SF-2 Each Detention Vault SF-3 Each Infiltration Pond SF-4 Each Infiltration Tank SF-5 Each Infiltration Vault SF-6 Each Infiltration Trenches SF-7 Each Basic Biofiltration Swale SF-8 Each Wet Biofiltration Swale SF-9 Each Wetpond SF-10 Each Wetvault SF-11 Each Sand Filter SF-12 Each Sand Filter Vault SF-13 Each Linear Sand Filter SF-14 Each Proprietary Facility SF-15 Each Bioretention Facility SF-16 Each SUBTOTAL STORMWATER FACILITIES: (B)(C)(D)(E) Page 5 of 7 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 CED Permit #:######## Existing Future Public Private Right-of-Way Improvements Improvements (D) (E) Description No. Unit Price Unit Quant.Cost Quant.Cost Quant.Cost Quant.Cost SITE IMPROVEMENT BOND QUANTITY WORKSHEET FOR DRAINAGE AND STORMWATER FACILITIES Quantity Remaining (Bond Reduction) (B)(C) WRITE-IN-ITEMS (INCLUDE ON-SITE BMPs) 15" Duraslot Slot Drain WI-1 200.00$ LF 1027 205,400.00 Culvert, DI, 10"WI-2 92.00$ LF 17 1,564.00 Cleanout, HDPE WI-3 200.00$ Each 47 9,400.00 Culvert, HDPE, 10"WI-4 58.00$ Each 67 3,886.00 WSDOT 96" Type 2, Flow Splitter WI-5 10,000.00$ Each 1 10,000.00 WSDOT 60" Type 2, Flow Splitter WI-6 7,500.00$ Each 1 7,500.00 SD Pump Station & Valve Vault WI-7 240,000.00$ Lump 2 480,000.00 Skydrol Containment w/ Safe Drain WI-8 5,095.00$ Each 4 20,380.00 MWS-L-8-12-6'-0"-V-UG WI-9 125,000.00$ Each 1 125,000.00 MWS-L-8-20-6'-0"-V-UG WI-10 210,000.00$ Each 1 210,000.00 816-1-CPS Oil Water Separator WI-11 50,000.00$ Each 2 100,000.00 Old Castle 816-LA Fuel Containment Vault WI-12 106,000.00$ Lump 2 212,000.00 Diversion Valve Vault w/ Valves WI-13 308,000.00$ Lump 1 308,000.00 WI-14 WI-15 SUBTOTAL WRITE-IN ITEMS:1,693,130.00 DRAINAGE AND STORMWATER FACILITIES SUBTOTAL:2,424,104.60 SALES TAX @ 10%242,410.46 DRAINAGE AND STORMWATER FACILITIES TOTAL:2,666,515.06 (B)(C)(D)(E) Page 6 of 7 Ref 8-H Bond Quantity Worksheet SECTION II.c DRAINAGE Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 Planning Division |1055 South Grady Way – 6 th Floor | Renton, WA 98057 (425) 430-7200 Date: Name:Project Name: PE Registration No:CED Plan # (LUA): Firm Name:CED Permit # (U): Firm Address:Site Address: Phone No.Parcel #(s): Email Address:Project Phase: Site Restoration/Erosion Sediment Control Subtotal (a) Existing Right-of-Way Improvements Subtotal (b)(b)-$ Future Public Improvements Subtotal (c)-$ Stormwater & Drainage Facilities (Public & Private) Subtotal (d)(d)2,666,515.06$ (e) (f) Site Restoration Civil Construction Permit Maintenance Bond 533,303.01$ Bond Reduction 2 Construction Permit Bond Amount 3 Minimum Bond Amount is $10,000.00 1 Estimate Only - May involve multiple and variable components, which will be established on an individual basis by Development Engineering. 2 The City of Renton allows one request only for bond reduction prior to the maintenance period. Reduction of not more than 70% of the original bond amount, provided that the remaining 30% will cover all remaining items to be constructed. 3 Required Bond Amounts are subject to review and modification by Development Engineering. * Note: The word BOND as used in this document means any financial guarantee acceptable to the City of Renton. ** Note: All prices include labor, equipment, materials, overhead and profit. 425-869-2670 tneu@dowl.com Apron E - Stalls Phase 1 ##-###### 419-471 Logan Ave N Parcel Number FOR APPROVAL ######## 8410 154th Avenue NE, Suite 120 2,666,515.06$ P (a) x 100% SITE IMPROVEMENT BOND QUANTITY WORKSHEET BOND CALCULATIONS 12/6/2019 Travis Neu 45379 DOWL R ((b x 150%) + (d x 100%)) S (e) x 150% + (f) x 100% Bond Reduction: Existing Right-of-Way Improvements (Quantity Remaining)2 Bond Reduction: Stormwater & Drainage Facilities (Quantity Remaining)2 T (P +R - S) Prepared by:Project Information CONSTRUCTION BOND AMOUNT */** (prior to permit issuance) EST1 ((b) + (c) + (d)) x 20% -$ MAINTENANCE BOND */** (after final acceptance of construction) -$ -$ 2,666,515.06$ -$ -$ 2,666,515.06$ -$ Page 7 of 7 Ref 8-H Bond Quantity Worksheet SECTION III. BOND WORKSHEET Unit Prices Updated: 06/14/2016 Version: 04/26/2017 Printed 12/18/2019 Appendix G Draft Geotechnical Investigation by S&EE Job No. 1818 S&EE S&EE REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED APRON E BOEING RENTON PLANT S&EE JOB NO. 1818 APRIL 17, 2019 (DRAFT) 1818rpt S&EE 3 S&EE SOIL & ENVIRONMENTAL ENGINEERS, INC. 16625 Redmond Way, Suite M 124, Redmond, Washington 98052, www.SoilEnvironmental.com (425) 868-5868 April 17, 2019 Mr. Andrew Fitzpatrick Construction Manager The Boeing Company CC: Mr. Mehdi Nakhjiri, PE, PSE Report of Geotechnical Investigation Proposed Apron E Boeing Renton Plant Dear Andrew, We present herewith our Geotechnical Report for the referenced project. Our services were authorized by your work order #35989, and have been performed in accordance with our proposals dated November 21, 2018. We appreciate the opportunity to provide our services. Should you have any questions regarding the contents of this report or require additional information, please let me know anytime. Very truly yours, SOIL & ENVIRONMENTAL ENGINEERS, INC. C. J. Shin, Ph.D., P.E. President 1818rpt S&EE TABLE OF CONTENTS Section Page 1.0 INTRODUCTION ................................................................................................................................................. 1 2.0 SCOPE OF WORK ............................................................................................................................................... 1 3.0 SITE CONDITIONS ............................................................................................................................................. 2 3.1 SITE HISTORY & GEOLOGY .......................................................................................................................... 2 3.2 SURFACE CONDITIONS ................................................................................................................................. 3 3.3 SUBSURFACE CONDITIONS ......................................................................................................................... 3 3.4 GROUNDWATER CONDITIONS ................................................................................................................. 4 4.0 LABORATORY TEST ......................................................................................................................................... 4 5.0 ENGINEERING EVALUATIONS AND RECOMMENDATIONS ................................................................ 5 5.1 GENERAL .......................................................................................................................................................... 5 5.2 PRELOAD ........................................................................................................................................................... 5 5.3 PILE FOUNDATION ......................................................................................................................................... 7 5.3.1 Pile Capacities .............................................................................................................................................. 7 5.3.2 Pile Settlement ............................................................................................................................................. 8 5.3.3 Pile Installation ........................................................................................................................................... 8 5.4 SHALLOW FOUNDATIONS ......................................................................................................................... 12 5.5 LATERAL EARTH PRESSURES .................................................................................................................... 14 5.6 STRUCTURAL FILL ........................................................................................................................................ 16 5.7 UNDERGROUND UTILITY CONSTRUCTION ............................................................................................ 16 5.8 DEWATERING ................................................................................................................................................. 18 5.9 PAVEMENT DESIGN RECOMMENDATIONS ............................................................................................ 18 5.10 SEISMIC CONSIDERATIONS ...................................................................................................................... 19 5.11 ADDITIONAL SERVICES ............................................................................................................................ 21 6.0 CLOSURE ............................................................................................................................................................. 22 FIGURE 1: SITE LOCATION MAP FIGURE 2: SITE & BORING LOCAITON PLAN FIGURE 3: LIQUIFACTION MAP FIGURES 4-6: GENERALIZED SOIL PROFILES FIGURES 7-10: PRELOAD FIGURES11-12: SOIL PARAMETERS FOR PILE ANALYSES FIGURE 13: RESULT OF LIQUEFACTION ANALYSIS APPENDIX A: FIELD EXPLORATION AND LOGS OF BORINGS APPENDIX B: LABORATORY TEST RESULTS 1818rpt S&EE REPORT OF GEOTECHNICAL INVESTIGATION PROPOSED APRON E For The Boeing Company 1.0 INTRODUCTION The proposed Apron E is located at current S1 Lot, in the southern portion of Boeing’s Renton campus. A Site Location Map is shown in Figure 1 and a Site & Boring Location Plan is shown in Figure 2, both are included at the end of this report. The S1 Lot is currently used for vehicle parking. The project will convert the parking lot into airplane apron for post-manufacture processing. The new apron will connect the existing Apron D located to the west of S1 Lot. A new paint hangar will be constructed in the southern portion of Apron E. This hangar will accommodate two 737 planes and will have dimensions of about 225 feet by 290 feet and a maximum height of about 85 feet. The column loads will range from about 500 to 1,000 kips. A single-story utility building about 30 feet wide by 175 feet long will be constructed near the paint hangar. At the time of this report, the location and the building’s column/floor loads have not been finalized. We understand that 4 transformers, each weigh 40 kips, 2 storage tanks, each has 15,000 gallons capacity, and other equipment unknow at this time will be installed inside or near the utility building. Blast fences, about 15 feet in height, will be constructed at the north side of Apron E, and a sound wall, about 25 feet in height will be construction along the eastern border. Other onsite structures will include light-weight crew shelters and tool sheds. New underground utilities will include storm, sewer, water, power and communication lines, and vaults for water quality control. The depth of the utility lines will be around 3 to 5 feet and the depth of the vaults may range from 6 to 12 feet. Minor grading will be performed and new concrete slab will be installed. The existing fire station building located at the southwest corner of S1 lot will be demolished and a new fire station will be constructed at the north side of N. 6th Street. 2.0 SCOPE OF WORK The purpose of our investigation is to provide geotechnical parameters and recommendations for design and construction. Specifically, the scope of our services includes the following: 1. Review of available geotechnical data. 1818rpt S&EE 2 2. Exploration of the subsurface conditions at the project site by the drilling of 6 shallow borings, 3 deep boring and the installation of 2 groundwater monitoring wells. 3. Performance of liquefaction evaluations. 4. Recommendations regarding foundation support. 5. Recommendations regarding the lateral soil pressures for shoring and subsurface retaining wall design. 6. Recommendation regarding passive soil pressure for the resistance of lateral loads. 7. Recommendation regarding preload and slab design. 8. Recommendations regarding the soil parameters for seismic design. 9. Recommendations regarding underground utility construction; recommendation regarding excavation shoring, angles of temporary slope, suitability of onsite soils for structural fill, and type of suitable imported fill. 10. Recommendations regarding dewatering. 11. Recommendations regarding pavement designs. 12. Attendance of design meetings. 13. Preparation of a geotechnical report containing a site plan, a description of subsurface conditions, and our findings and recommendations. 3.0 SITE CONDITIONS 3.1 SITE HISTORY & GEOLOGY Renton Boeing plant is located at the south end of Lake Washington. During WW II, the plant area was leveled by about 3 to 7 feet thick of fill. The native soils immediately under the fill include alluvial deposits that are over 100 feet in thickness. Published geologic information (Geologic Map of The Renton Quadrangle, King County, Washington by D.R. Mullineaux, 1965) indicates that the alluvial soils are underlain by Arkosic sandstone. S&EE performed a few soil test borings in 2012 – 2013 at North Bridge site 1818rpt S&EE 3 located at the northwest corner of the plant. These borings found glacially deposited and consolidated soil (hard silt) at depths of about 150 to 170 feet. Boring data from our previous projects at the south side of Renton Airport show that the hard silt is underlain by sandstone. Seismic Hazards Seattle Fault is the prominent active fault closest to the site. The fault is a collective term for a series of four or more east-west-trending, south-dipping fault strands underlying the Seattle area. This thrust fault zone is approximately 2 to 4 miles wide (north-south) and extends from the Kitsap Peninsula near Bremerton on the west to the Sammamish Plateau east of Lake Sammamish on the east. The four fault strands have been interpolated from over-water geophysical surveys (Johnson, et al., 1999) and, consequently, the exact locations on land have yet to be determined or verified. Recent geologic evidence suggests that movement on this fault zone occurred about 1,100 years ago, and the earthquake it produced was on the order of a magnitude 7.5. Due to the close proximity of Seattle Fault, the loose subsoils at the site have high liquefaction potential during strong earthquakes. This high liquefaction susceptibility is shown in Figure 3: Preliminary Liquefaction Susceptibility Map of the Renton Quadrangle, Washington by Stephen Palmer. 3.2 SURFACE CONDITIONS The project site is bordered to the north by N. 6th Street, to the west by Apron D, to the south by Renton Memorial Stadium and to the east by Logan Ave N. Currently, the site is occupied by the S1 parking lot for Boeing employees. The surface conditions consist of asphalt paving with some landscaping surrounded by curbs and a concrete sidewalk in the northwest corner. The ground surface elevations vary from 24.5 feet to 27.5 feet. The asphalt is 2.5 to 3 inches thick and in relatively good conditions, except some minor cracking near underground utilities. There are storm water catch basins throughout the parking lot and street lights in the landscaping areas. The Boeing fire station is located in the southwest corner of the lot. 3.3 SUBSURFACE CONDITIONS We obtain the subsurface conditions at the site by the drilling of 9 soil test borings, B-1 through B-9. Borings B-1 to B-3 were drilled in the southern portion of the site to a depth of 150 feet, whereas B-4 to B- 9 were drilled in the northern portion of the site to depths of 20 to 30 feet. The locations of these borings are shown in Figure 2. The boring logs are included in Appendix A of this report. Based on the boring data, the subsurface conditions at the project area include fill soils over alluvial 1818rpt S&EE 4 deposits. The fill is 5 feet in thickness except at B-7 where only 3 feet of fill was found. The fill is moderately to well-compacted pitrun (a mix of sand and gravel), except at B-7 where well-compacted recycled concrete is present. This fill is underlain by young/unconsolidated alluvium to depths of 70 to 75 feet. Below these depths the soils become older/consolidated alluvium which extends to the maximum exploration depth of 150 feet. These stratifications are depicted in Figures 4 to 6. In general, the young alluviums are soft/loose and include interbedded silt, silty sand and sand. Pockets and layers of dense soils exist in the young alluvium, as well as lenses of peat and organic rich soils. The older alluviums are firm/dense and include thick (15 to 30 feet) layers of sand and gravel. The 3 deep borings are terminated in a very dense layer of sand and gravel. 3.4 GROUNDWATER CONDITIONS A groundwater monitoring well was installed in Borings B-1 and B-7. We measured groundwater depths from December 2018 to March 2019 and the results are presented in the table below. The groundwater depth fluctuated from 7.7 feet to 8.4 feet with the highest in March. Boring Number Surface Elevation (ft) Depth (ft) Elevation (ft) B-1 27.1 7.8 to 8.4 19.3 to 18.7 B-7 24.4 7.7 to 8.3 16.7 to 16.1 4.0 LABORATORY TEST Selected soil samples were transported to our sub-contracted soil laboratory, HWA in Bothell, WA for engineering property tests. The tests include sieve analyses, Atterberg Limits, and consolidation. The test results were utilized in our seepage flow evaluation, liquefaction-potential determination, and settlement calculations, respectively. The results are included in Appendix B. 1818rpt S&EE 5 5.0 ENGINEERING EVALUATIONS AND RECOMMENDATIONS 5.1 GENERAL 1. The subsurface soils at the site include soft and loose, un-consolidated alluvial soils from near ground surface to depths of 70 to 75 feet. Other than occasional pockets and layers of dense soil, the young alluviums have low shear strength, high compressibility, and they are prone to liquefaction during severe earthquakes. As such, these soils are not suitable for shallow foundations of significant loads. We thus recommend deep foundations for the support of the paint hangar. We have considered augercast piles and driven pipe piles. We believe close-ended, driven pipe piles will be most cost‐effective as they have relatively high capacity and low downdrag loads. Shallow foundations including spread footings and mats are recommended for the support of light-weight structures such as blast fence, sound wall, crew shelters, utility shed, etc. 2. The results of our settlement analyses show maximum settlements of about 4 to 6 inches under hangar’s floor load. We believe this settlement is excessive and thus recommend preload to pre- induce the ground settlement. To avoid elevated downdrag forces on piles the preload should be conducted prior to pile installation. The utility building may house heavy equipment. As such, we recommend that preload be considered for this building. Some heavy equipment may be installed outside the utility building. We recommend that preload be considered for areas to support transformers, above ground storage tanks, and any other equipment that has a total load greater than 20 kips. 3. Liquefaction can result in sand boils and uneven ground settlements that will threaten the slab-on- grade. As such, reinforcements in slab-on-grade should be considered. Details of our recommendations are presented in the following sections. 5.2 PRELOAD The preload program should begin by breaking the asphalt pavement into pieces of less than 10 feet by 10 feet in size. This will promote uniform ground settlement and avoid bridging effect over non-uniform subgrade reaction. The preload should consist of non-structural fill soil or concrete ecology blocks. The former should be at least 7 feet in thickness and have a minimum in-place density of 120 pcf (pounds per cubic feet). The fill 1818rpt S&EE 6 should be compacted to the extent that the material can support the construction equipment. The surface should be graded for surface drainage. The preload should have 1.5H:1V side slopes and the edge/top of the slope should extend at least 15 feet beyond the building perimeters. To reduce preload footprint, side slopes can be replaced with geogrid reinforced block walls. In this case, the edges of the wall should be at least 15 feet beyond the building perimeters. A sketch showing geogrid reinforcement is shown in Figure 7. If the option of concrete ecology blocks is chosen, the blocks should be stacked to 6 feet high. A 6-inch gap should be allowed between block walls, and the gap filled with sand. The purpose of this gap is to prevent uneven contact pressure at the ground surface if the top of blocks tilt and wedge. Figures 8 and 9 show the results of preload settlement analyses. We expect that total settlement under the preload will be about 6 inches and will take about 8 to 10 weeks to reach maturity. Figure 9 also shows that at a distance of 27 feet from the edge of preload, the ground settlement will reduce to 1/2 inch and become negligible beyond. A total of 3 ground settlement monitoring markers should be installed in the preload area prior to the placement of preload fill or concrete blocks. A sketch showing the settlement marker is included in Figure 10. One of these markers should be placed near the center of the preload, the other two placed from the edges of preload a distance about 1/4 of the preload width/length. The movement of the settlement markers should be surveyed initially (prior to the placement of preload), once every day for the first 5 days, and once every week thereafter. The survey results should be transmitted to our office within 24 hours. We will determine the termination of the preload period upon theoretical (about 90%) maturity is reached. Subgrade Preparation for Slab-On-Grade: Upon preload completion the preload soil or concrete blocks, and broken asphalt pavement should be removed. The subgrade should then be excavated to allow for a 12-inch- thick slab base course. The excavated subgrade should then be thoroughly compacted by a vibratory roller weighing at least 10 tons. The roller should make at least 4 passes (back and forth is one passes) in each perpendicular direction. Any soft, wet or organic soils encountered at the subgrade should be over-excavated. The over-excavation should be backfilled with the base course material stated below. The subgrade preparation should be monitored by a site inspector from our office. Base course material should consist of well-graded crushed rock or a blend of commercial rock products conforming to WSDOT specifications for Crushed Surfacing, Specification 9-03.9(3). The base course should have adequate moisture contents at the time of placement and be compacted to a firm and unyielding condition using a mechanical compactor approved by our site inspector. 1818rpt S&EE 7 Slab-On-Grade Design: Concrete slab-on-grade can be designed using a subgrade reaction modulus of 200 pounds per cubic inch (pci). If thickened edges are to be installed, the slope at the thickened edges should be 2H:1V or flatter. 5.3 PILE FOUNDATION As previously mentioned, we believe that close-ended, driven pipe piles will be the most cost‐effective foundation system for the support of the proposed paint hangar. Steel pipe is a good choice for driven piles given their flexibility in relation to cutting and splicing pile sections. To provide adequate capacities, we recommend that the piles be embedded at least 20 feet into the load bearing layer. We estimate that the pile length will be about 90 to 100 feet. Actual pile lengths will depend on driving resistance and other factors, and may need to be adjusted in the field after initial piles are installed; see Section 5.3.3.1 for more details. We further recommend that steel, driven pipe piles have a ½-inch minimum wall thickness and the piles be spaced at least 3 pile diameters ON CENTER. Filling the pile with concrete is not necessary from the geotechnical standpoint. 5.3.1 PILE CAPACITIES Tables 1 to 3 below summarize the pile capacities. The allowable downward loads include a safety factor of 2 and have subtracted the downdrag loads of 90 and 120 kips for the 18-inch and 24-inch piles, respectively. These allowable downward capacities can be increased by 1/3 when considering the transient loads such as wind seismic forces. The allowable upward capacity includes a safety factor of 1.5. TABLE 1: Capacity of 18-inch Pile (kips) Pile Length 1 (feet) Ultimate Downward Capacity (Static) Allowable Downward Capacity (Downdrag Subtracted) Allowable Upward Capacity (Static) 2 Allowable Upward Capacity (Liquefaction) 3 90 625 165 145 140 100 680 250 160 155 1Pile Length measured from ground surface 2Soil parameters for static state are included in Figure 11 3Soil parameters for liquefaction condition are included in Figure 12 1818rpt S&EE 8 TABLE 2: Capacity of 24-inch Pile (kips) Pile Length (feet) Ultimate Downward Capacity (Static) Allowable Downward Capacity (Downdrag Subtracted) Allowable Upward Capacity (Static) Allowable Upward Capacity (Liquefaction) 90 980 270 225 165 100 1,050 310 250 185 TABLE 3: Lateral Capacity (kips, with liquefaction) Pile Diameter (inch) ½-inch Top Deflection 1-inch Top Deflection 18 15 25 24 25 40 Group effect for lateral capacity reduction should apply. That is, the capacity of the trailing pile should be reduced by 60% when spaced at 3 pile diameters. Group action diminishes at a pile spacing of 7 pile diameters and the reduction can be lineally interpreted in between. Additional lateral resistance can be obtained from the passive earth pressure against pile caps and grade beams, as well as friction at the bottom of slab-on-grad. The former can be obtained using an equivalent fluid density of 250 pounds per cubic feet, and the latter using a coefficient of friction of 0.5. These values include a safety factor of 1.5. 5.3.2 PILE SETTLEMENT Pile settlement will result from elastic compression of the piles and the supporting soils. Our analyses show that the total settlement under the allowable loads will be on the order of 1/2 to 3/4 inch. 5.3.3 PILE INSTALLATION Steel pipe piles should be driven with a pile hammer that can deliver sufficient driving energy to achieve capacity and embedment but not overstress the steel. The choice of hammer should be evaluated as discussed later in this section. Based on the boring data, we anticipate penetration depths to refusal may vary significantly from one pile cap to another and even between piles in the same cap. For piles in large groups, we recommend installation from the center and work outward. 1818rpt S&EE 9 Heavy-duty hammers can produce high production rates but can also damage piles. To reduce potential for damage, the pile driving stresses should be kept sufficiently below the yield stress of the steel. We recommend a maximum driving stresses at 90 percent of the steel yield stress (FHWA 2005). Pile driving stresses can be measured indirectly in the field using a dynamic pile driving analyzer (PDA) or estimated using a wave equation computer program (WEAP). Our previous pile‐driving experience suggests it is often difficult to drive thin‐walled pipe piles. Based on this we recommend minimum wall thickness of 1/2 inch and piles of at least 60 kips per square inch (ksi) yield stress steel. As parts of the bid package, the pile contractor should perform a drivability study based on their intended hammers. The purpose of the study is to establish the pile acceptance criteria and ensure the proposed driving system will not overstress the piles. The study should include details of the hammers and results of WEAP analyses. The contractor should submit a drivability study report to the design team for review and approval no later than 14 days prior to driving the test or production piles. The report of drivability study should include at least the followings: 1. An assessment of the proposed hammer driving system’s ability of driving the pile to the ultimate capacity (see Tables 1 and 2). 2. The expected stress levels in the piles at the maximum expected hammer energy and any recommended limitations on hammer energy or fuel settings to ensure the pile stresses do not exceed 90% of the pile yield stress. 3. A pile inspector’s charts showing hammer stroke (ft) or energy versus pile penetration rate (blows/inch). 5.3.3.1 PILOT PILE PROGRAM After the drivability study report is approved, we recommend that a pre‐production pilot pile program be performed. The purposes of this program include the followings: • Confirmation of the required pile wall thickness, pile steel grade, and pile tip construction required to achieve the ultimate pile capacity. • Confirmation of the pile lengths and embedment into the bearing layer required to achieve capacities across the site. 1818rpt S&EE 10 • Optimization of pile driving equipment and procedures to achieve capacity and not damage piles nor existing structures. The contractor may consider the use of vibratory hammer for driving through the upper 50 feet of loose soils, then impact hammer thereafter. The choice of hammer may affect the production rate, and should be the decision by the contractor. The pilot pile program can potentially save budget and time by reducing uncertainty in pile lengths required to achieve capacities and avoid unnecessary splicing. In general, the number of pilot piles may range from 5% to 10% of the production piles. The actual number will depend on the installation results and should be finalized/modified by the design team. The pilot piles can be used as production piles if they reach the required capacity, are not damaged, and have at least 20 feet of embedment into the bearing soils. At the time of pilot pile installation, the contractor should provide details of driving equipment including hammer model, hammer cushion, cap weight and pile cushion. The contractor should also retain a subconsultant for the performance of dynamic pile testing for each pilot pile. Dynamic pile testing includes instrumenting each pile with gages so pile driving analyzer (PDA) can be used to record stresses in the steel during driving and the estimated total pile capacity can be obtained. After PDA testing during initial driving and re-striking the piles, the subconsultant should also perform Pile Wave Analysis Program (CAPWAP) for the estimations of side and toe pile capacities. All pilot piles should be driven to refusal which is tentatively be defined as 15 blows per inch for the last 4 inches of driving. This refusal criterion may change depending on hammer used and PDA results. The pile re-strike should be performed for all pilot piles after at least 72 hours from initial installation. Ground vibration and Noise: Ground vibration is typically not a problem for structures that are over 100 feet away. However, if the owner would like to evaluate the vibration effects (or lack of), the pile contractor should use geophones to measure ground vibrations in the area surrounding the pile during driving to determine the vibration amplitude and the rate of decay in amplitude with distance from the driving location. The geophones are typically arranged in an array, generally in the direction of existing structures, with initial distances from the driven pile of approximately 25, 50, and 75 feet. If necessary, separate geophones can be installed on nearby structures of interest. At owner’s direction, the contract may need to monitor the noise level during pile driving. 1818rpt S&EE 11 5.3.3.2 PILE OBSTRUCTION Buried timber piles often found at Renton plant. Old footings or slab may also present below the ground surface. Shallow obstruction can be removed by excavation, whereas deeper obstruction may need relocation of the pile. In this event, the structural engineer should be informed and provide replacement pile location. 5.3.3.3 DRIVEN PILE FIELD CAPACITY VERIFICATION We recommend verifying the pile capacity in the field based on a dynamic pile driving formula used in conjunction with the data from the pilot pile program. The WSDOT pile driving formula has the following form: Rn = 6.6 × Feff × E × Ln(10N) where: Rn = ultimate bearing resistance, in kips Feff = hammer efficiency factor E = developed energy, equal to W times H, in ft-kips W = weight of ram, in kips H = vertical drop of hammer or stroke of ram, in feet N = average penetration resistance in blows per inch for the last 4 inches of driving Ln = the natural logarithm, in base “e” Both theoretical considerations and pile installation experience indicate that the pile capacity during and just after installation (resistance to driving) is less than the long‐term static pile capacity. This occurs because the vibration from driving induces liquefaction in the nearby soils, and thus reduce their shear strength. These strength losses during driving are usually regained in a few days after initial driving. We recommend that piles that have lower than the recommended ultimate capacity be re-driven 12 to 24 inches after a minimum waiting period of 72 hours. The long-term ultimate pile capacity should be estimated using the blow counts in the first 3 inches, after the pile hammer reaches its intended maximum driving force. 1818rpt S&EE 12 5.4 SHALLOW FOUNDATIONS We recommend that spread footings be used for the support of blast fence and sound wall, and mat foundation be used for the support of crew shelter, storage shed, and similar light-weight structures. Details of our recommendations are presented below. Spread Footing for Blast Fence and Sound Wall A very soft to soft silt is present at depths of 3 to 5 feet from the ground surface. This material has a high compressibility. To mitigate the potential uneven settlement from such compressibility, we recommend that a geo-grid reinforced gravel raft be installed at the base of the footings. This raft should be 2 feet in thickness and include two layers of geogrid, one placed at the bottom and one at the mid-height of the raft. The edges of the raft should be extended 2 feet beyond the edges of the footing. The geogrid should be Tensar TriAx or equivalent. The geogrid should be placed without wrinkles and have a minimum 12 inches overlap. The gravel should consist of well-graded crushed rock or a blend of commercial rock products conforming to WSDOT specifications for Crushed Surfacing, Specification 9-03.9(3). The rock should have adequate moisture content (+/- 2% from optimum) at the time of placement. The material should be placed in 6-inch thick lifts and each lift be compacted by at least 4 passes (back-and-forth is one pass) of a vibratory plate compactor that weighs at least 800 pounds. Note that very soft to soft soils exist near the footing subgrade. Heavy compactors are not suitable as they may destabilize subgrade. Prior to the construction of the gravel raft, all loose soil cuttings should be removed from the subgrade. If wet or organic soils are present at the subgrade, they should be removed by over-excavation. The over- excavation should be backfilled with compacted crushed rock. The subgrade preparation and gravel raft construction should be monitored by a site inspector from our office. Bearing Capacity: We recommend that spread footings be designed with an allowable bearing load of 1,500 pounds per square feet (psf). This value includes a safety factor of at least 2. Since the stress zone under the footings include non-granular silt, we recommend no increase of capacity for transient loads including engine blast, wind and seismic loads. Settlement: At the time of his report, the load information for blast fence and sound wall are not finalized. Based on our experience, we believe that the footing may experience a maximum total settlements on the order of 1/2 inch. 1818rpt S&EE 13 Lateral Resistance: Lateral resistance can be obtained from the passive earth pressure against the footing sides and the friction at the contact of the footing bottom and bearing soil. The former can be obtained using an equivalent fluid density of 250 pounds per cubic foot (pcf), and the latter using a coefficient of friction of 0.5. These values include a safety factor of 1.5. Frost Protection and Minimum Width: Exterior footings should be founded at least 18 inches below the adjacent finished grade to provide protection against frost action. Footing width should be at least 18 inches to facilitate construction. Footing Drain: We do not expect any subsurface flow near the bottom of the footings. Therefore, no footing drain is necessary. Mat Foundation Load-supporting mats can be designed using a subgrade reaction modulus of 100 pounds per cubic inc hes (pci). We recommend that mats be underlain by a 6-inch thick crushed rock base course. The crushed rock should have an adequate moisture content (+/- 2% from optimum) at the time of placement, and be compacted to a firm and non-yielding condition using a compactor that weighs at least 800 pounds. Prior to the base course placement, all loose soil cuttings should be removed from the subgrade. If wet or organic soils are present at the subgrade, they should be removed by over-excavation. The over-excavation should be backfilled with compacted crushed rock. The subgrade preparation and base course construction should be monitored by a site inspector from our office. Again, if thickened edges are to be installed, the slope between the slab and thickened edges should be 2H:1V or flatter. 1818rpt S&EE 14 5.5 LATERAL EARTH PRESSURES Lateral earth pressures on retaining walls or permanent subsurface walls, and resistance to lateral loads may be estimated using the following recommended soil parameters: Soil Density (PCF) Equivalent Fluid Unit Weight (PCF) Coefficient of Friction Active At-rest Passive 125 45 55 200 0.5 Note: 1) Hydrostatic pressures are not included in the above lateral earth pressures. A 60% reduction should apply to the passive pressure for below groundwater table condition. 2) Lateral earth pressures are appropriate for level structural fill placed behind and in front of walls. The active case applies to walls that are permitted to rotate or translate away from the retained soil by approximately 0.002H, where H is the height of the wall. This would be appropriate for a cantilever retaining wall. The at-rest case applies to unyielding walls, and would be appropriate for walls that are structurally restrained from lateral deflection such as basement walls, utility trenches or pits. SURCHARGE INDUCED LATERAL LOADS Additional lateral earth pressures will result from surcharge loads from floor slabs or pavements for parking that are located immediately adjacent to the walls. The surcharge-induced lateral earth pressures are uniform over the depth of the wall. Surcharge-induced lateral pressures for the "active" case may be calculated by multiplying the applied vertical pressure (in psf) by the active earth pressure coefficient (Ka). The value of Ka may be taken as 0.4. The surcharge-induced lateral pressures for the "at-rest" case are similarly calculated using an at-rest earth pressure coefficient (Ko) of 0.6. 1818rpt 15 S&EE SEISMIC INDUCED LATERAL LOADS For seismic induced lateral loads, the dynamic force can be assumed to act at 0.6 H above the wall base and the magnitude can be calculated using the following equation: Pe = 14H Where Pe = seismic-induced lateral load in psf H = wall height in feet BACKFILL IN FRONT OF RETAINING WALLS Backfill in front of the wall should be structural fill. The material and compaction requirements are presented in Section 5.6. The density of the structural fill can be assumed to be 130 pounds per cubic feet. BACKFILL BEHIND RETAINING WALLS Backfill behind the wall should be free-draining materials which are typically granular soils containing less than 5 percent fines (silt and clay particles) and no particles greater than 4 inches in diameter. The backfill material should be placed in 6 to 8-inch thick horizontal lifts and compacted to a firm and non-yielding condition. Care must be taken when compacting backfill adjacent to retaining walls, to avoid creating excessive pressure on the wall. DRAINAGE BEHIND RETAINING WALLS Unless the wall is designed to support hydrostatic pressure, rigid, perforated drainpipes should be installed behind retaining walls. Drainpipes should be at least 4 inches in diameter, covered by a layer of uniform size drain gravel of at least 12 inches in thickness, and be connected to a suitable discharge location. An adequate number of cleanouts should be installed along the drain line for future maintenance. 1818rpt 16 S&EE 5.6 STRUCTURAL FILL Structural fill should be used for utility backfill, and in areas that will support loads such as slab, pavement, walkway, etc. Structural fill materials should meet both the material and compaction requirements presented below. Material Requirements: Structural fill should be free of organic and frozen material and should consist of hard durable particles, such as sand, gravel, or quarry-processed stone. The existing onsite fill soils are suitable on a selective basis; and its suitability should be confirmed by a site inspector from our office. The native soils below the existing fill are not suitable for structural fill. Suitable imported structural fill materials include silty sand, sand, mixture of sand and gravel (pitrun), recycle concrete, and crushed rock. All structural fill materials should be approved by an engineer from our office prior to use. Please note that: 1) Flowable CDF (Control Density Fill) is considered an acceptable structural fill. The material should have a minimum compressive strength of 150 psi; 2) Recycled concrete often has a fines content exceeding 20%, making the material sensitive to moisture. As such, the material may be difficult to use in wet winter months. Placement and Compaction Requirements: Structural fill should be placed in loose horizontal lifts not exceeding a thickness of 6 to 12 inches, depending on the material type, compaction equipment, and number of passes made by the equipment. Structural fill should be compacted to a firm and non-yielding condition. The native soils near the ground surface are soft and loose, and groundwater is shallow (at about 7 feet in the winter months). Therefore, compaction requirements using conventional method such as 95% Proctor may not be suitable for the project site, as this may lead to disturbance to the subgrade soils and uneven settlement of the underground utilities. We thus recommend performance base requirements including appropriate compaction equipment, moisture content, lift thickness, number of passes, and approval by our onsite inspector. 5.7 UNDERGROUND UTILITY CONSTRUCTION 5.7.1 TEMPORARY CUTS When temporary excavations are required during construction, the contractor should be responsible for the 1818rpt 17 S&EE safety of their personnel and equipment. The followings cut angles are provided only as a general reference: Open cuts shallower than 3 feet may be cut vertically. For cuts over 3 feet and shallower than 5 feet, the cut should be sloped at 1H:1V or flatter. Cuts over 5 feet in depth or below groundwater table may need to be 1.5H:1V or flatter. For a combination of open cut and shoring, benching in the upper 2 to 4 feet works well in the past as it lessens the overburden pressure and facilitates backfill. The benches should have a 1:1 ratio for bench height and width. To avoid bank caving, the height of each bench should be limited to 2 feet. 5.7.2 SHORING DESIGN Excavation shoring will be required at locations of space constraint. As a starting point, we recommend the following soil parameters for the design. We should review the design and provide recommendations for necessary adjustments. Soil’s total unit weight:115 and 130 pcf (pounds per cubic feet) for native soils and existing fill, respectively Soil’s buoyant unit weight: 45 and 60 pcf for silt and sand, respectively. Active soil pressure: 45 pcf, equivalent fluid density, above groundwater table Active soil pressure: 20 pcf, equivalent fluid density, below groundwater table Passive soil pressure: 200 pcf, equivalent fluid density, above groundwater table (include 1.5 safety factor) Passive soil pressure: 70 pcf, equivalent fluid density, below groundwater table (include 1.5 safety factor) Imbalanced hydrostatic pressure should be added to the active side. A 2-foot over-excavation at the passive side should be considered in the design. 5.7.3 UTILITY SUBGRADE PREPARATION All loose soil cuttings should be removed prior to the placement of bedding materials. Wet and loose subgrades should be anticipated. The contractor should make efforts to minimize subgrade disturbance, especially during the last foot of excavation. Note that subgrade disturbance in wet and loose soil is inevitable, and subgrade stabilization is necessary in order to avoid re-compression of the disturbed zone. Depending on the degrees of disturbance, the stabilization may require a layer of quarry spalls (2 to 4 inches or 4 to 8 inches size crushed rock). Based on our experience at Apron D, when compacted by a hoepac or the dynamic force of the excavator’s bucket, a 12 to 18 inches thick layer of spalls would sink into the loose and soft soils, interlock and eventually form a stable subbase. A chocker stone such as 5/8” x 1-1/4” clean crushed rock should be installed over the quarry spalls. This stone should be at least 4 inches in thickness and should be compacted to a firm and non-yielding condition by a mechanical compactor that 1818rpt 18 S&EE weighs at least 800 pounds. In the event that soft silty soils above groundwater table are encountered at subgrades, the subgrade should be over-excavated for a minimum of 6 inches. A non-woven geotextile having a minimum grab tensile strength of 200 pounds should be installed at the bottom of the over- excavation and the over-excavation backfilled with 1-1/4” minus crushed rock. The material should have adequate moisture and be compacted to a firm a non-yielding condition using a mechanical compactor approved by our site inspector. 5.7.4 BEARING CAPACITY AND SUBGRADE MODULUS Subgrade so prepared should have an allowable bearing capacity of 1,500 psf (pounds per square feet), and a subgrade modulus of 50 pci (pounds per cubic inches). The bearing capacity includes a safety factor of 3. Total settlement under these loads should be on the order of 1/4 to 1/2 inch. 5.8 DEWATERING Dewatering will be required for excavations deeper than the groundwater table. Based on our experience at Apron D, we believe that for excavations shallower than 8 to 9 feet, dewatering may be achieved using local sumps. The contractor should install sumps at locations and spacing that are best fitted for the situation. To facilitate drainage, the sump holes should be at least 2 feet below the excavation subgrade. If possible, the granular backfill around the sump should make hydraulic connection with the crushed rock or quarry spalls placed for subgrade stabilization. For dewatering deeper than 9 feet, our experience at Aprons A and D has shown that wellpoints installed to a depth of about 25 feet and spaced at 5 to 8 feet can draw down groundwater to depths of about 15 to 18 feet below ground surface. The boring data reveal that the majority of the water-bearing soils above the depth of 20 feet are low permeability silt or moderate to low permeability silty fine sand. Wellpoints installed in these soils can expect low discharge rates, about 1/2 to 2 gallon per minute (gpm) per well. The exception to this is the fine to medium sand encountered at Boring B-5. This soil has a moderate permeability, and wellpoints installed in this soil may experience about 5 gpm per well. 5.9 PAVEMENT DESIGN RECOMMENDATIONS We recommend that all pavement subgrades be proof-rolled to identify areas of soft, wet, organic, or unstable soils. Proof-rolling should be accomplished with a heavy (10-ton) vibratory roller, front-end- 1818rpt 19 S&EE loader, or loaded dump truck (or equivalent) making systematic passes over the subgrade while being observed by a site inspector from our office. In areas where unstable and/or unsuitable subgrade soils are observed, these soils should be over-excavated a minimum 12 inches. Additional over-excavation depth may be required to remove buried debris, organic or very soft soil. Woven geotextile having a minimum 200 pounds grab tensile strength may be necessary for additional subgrade stabilization. The geotextile should be placed with 12-inch overlaps and all wrinkles removed. The over-excavation should be monitored by an inspector from our office. Our inspector will provide recommendations regarding the final depth of over-excavation and the preparation of the over-excavated subgrade. The over-excavation should then be backfilled with pavement base course material. The material should have adequate moisture content, and be compacted to a firm and non-yielding condition by a compactor approved by our site inspector. After proof-rolling, the top 12 inches of the subgrade should be thoroughly compacted to a firm and non- yielding condition. The subgrade soil should have adequate moisture content (within +/-2% from optimum) at the time of compaction. Asphalt pavements constructed over proof-rolled and compacted subgrades, as specified above, can be designed with a CBR (California Bearing Ratio) value of 12; concrete pavement can be designed with a subgrade reaction modulus of 100 pci (pounds per cubic inches). A typical standard-duty (lightweight) pavement section that was used on similar projects at the plant consists of 3 inches of Class B asphalt over 6 inches of base course. A heavy-duty pavement section could consist of 6 inches of Class B asphalt over 12 inches of base course. A concrete pavement section could consist of 8 inches of reinforced concrete over 6 inches of base course. Base course under pavements should consist of well-graded crushed rock; well-graded recycle concrete; or a blend of commercial rock products conforming to WSDOT specifications for Crushed Surfacing, Specification 9-03.9(3). The base course should have adequate moisture content (within +/-2% from optimum) and be compacted to a firm and unyielding condition. 5.10 SEISMIC CONSIDERATIONS SITE CLASS AND SEISMIC DESIGN PARAMETERS We have evaluated the geotechnical-related parameters for seismic design in accordance with 2015 IBC. The spectral responses were obtained from USGS website using a latitude of 47.48867 degrees and 1818rpt 20 S&EE a longitude of -122.208023 degrees. The values for Site Class B (rock) are: SS = 1.444 g (short period, or 0.2 second spectral response) S1 = 0.541 g (long period, or 1.0 second spectral response) Using the boring data, we determined that the subsoils correspond to Site Class E (“Soft Clay Soil”). The site coefficient values are used to adjust the mapped spectral response acceleration values to get the adjusted spectral response acceleration values for the site. The recommended Site Coefficient values for Site Class E are: Fa = 0.9 (short period, or 0.2 second spectral response) Fv = 2.4 (1.0 second spectral response) The Peak Ground Acceleration (PGA) is 0.595g. SEISMIC HAZARDS Liquefaction during strong seismic events is the primary geotechnical hazard at the site. This is a condition when vibration or shaking of the ground results in the excess pore pressures in saturated soils and subsequent loss of strength. Liquefaction can result in ground settlement or heaving. In general, soils that are susceptible to liquefaction include saturated, loose to medium dense sands and soft to medium stiff, low-plasticity silt. The evaluation of liquefaction potential is complex and is dependent on many parameters including soil’s grain size, density, and ground shake intensity, i.e., Peak Ground Acceleration (PGA). We have performed liquefaction analyses using a computer program, Lique-Pro. Figure 13 shows the results of the analysis. These results indicate that a ground settlement on the order of 10 inches may occur and the liquefaction zone may extend to a depth of 70 feet. We believe that the proposed preload may reduce the ground settlement to about 5 to 7 inches. This liquefaction-induced settlement may result in severe damage to slab-on-grade. As the piling penetrates the liquefaction zone, impacts to the hangar building should be minimal. 1818rpt 21 S&EE 5.11 ADDITIONAL SERVICES We recommend the following additional services during the construction of the project: 1. Review design plans to confirm that our geotechnical recommendations are properly implemented in the design. 2. Review contractor’s submittals. 3. Response to contractor’s RFI. 4. Construction monitoring services. The tasks of our monitoring service will include the followings: 4.1 Monitoring preload construction; review preload progress and determination the maturity of preloading. 4.2 Review and approval of pile contractor’s drivability report. 4.3 Monitoring pilot piles installation. We will record the blow counts during initial driving, pile restrikes, and hammer energy; review of contractor’s PDA testing during initial driving and re-strike; review of the contractor’s CAse Pile Wave Analysis Program (CAPWAP) for the estimations of side and toe pile capacities. 4.4 Monitoring production piles installation. Our representative will evaluate the contractor’s operation and collect and interpret the installation data. We will confirm the predetermined penetration depth, monitor variations in subsurface conditions, and determine the required penetration depths. 4.5 Monitoring gravel raft, footing and mat foundation constructions. 4.6 Monitoring the installation of underground utilities; observation of subgrade preparation and recommendations regarding subgrade stabilization. 4.7 Observation and approval of structural fill material, its placement and compaction. Our representative will confirm the suitability of the fill materials, perform field density tests, and assist the contractor in meeting the compaction requirements. 1818rpt 22 S&EE 4.8 Monitoring subgrade preparation for slab-on-grade. 4.9 Recommendation regarding construction dewatering. 5. Preparation and distribution of field reports. 6. Other geotechnical issues deemed necessary. 6.0 CLOSURE The recommendations presented in this report are provided for design purposes and are based on soil conditions disclosed by the available geotechnical boring data. Subsurface information presented herein does not constitute a direct or implied warranty that the soil conditions between exploration locations can be directly interpolated or extrapolated or that subsurface conditions and soil variations different from those disclosed by the explorations will not be revealed. The recommendations outlined in this report are based on the assumption that the project plan is consistent with the description provided in this report. If the plan is changed or subsurface conditions different from those disclosed by the exploration are observed during construction, we should be advised at once so that we can review these conditions, and if necessary, reconsider our design recommendations. LOGAN AVEEXIT 5 900 515 900 EXIT 4 EXIT 4A 405 405 167 EXIT 4B 405 169 167 D9 D40 D35 D30 EXIT 2B From Issaquah From Bellevue 4-04 Medical Clinic Safety LK WASHINGTON BLVD N From Seattle LAKE WASHINGTON Boeing Employees Flying Association RA I N I E R A V E N 4-41 4-20 4-21 4-69 4-402 4-78 4-77 4-79 4-71 4-42 4-45 Apron D 5-27 5-403 5-288 9 7 1 16 17 15 12 13A 14 10-18 GARDEN AVE N N EVA NEDRAGEVA KRAPN 8TH ST 11 10-16 10-13 4-89 4-88Badge Office 10-20 10-80 Hub 4-17 4-90 4-75 4-81 4-82 4-83 4-86 Renton Airport From I-5 From Longacres Park From Kent and Auburn From Enumclaw Apron A Apron BRAINIER AVE N AIRPORT WAY RE N T O N A V E S S 3RD ST S 2ND ST Renton Stadium 5-09 5-02 S U N S E T B L V D W BENSON RD S M. L . K I N G J R W A Y S SW 10TH S T OAKESDALE AVE SW SW 19TH ST SW 16TH ST DNOMYAR WS EVA WS EVA DNILTALBOT RD S EVA NIAM HOUSER WAY N LOGAN AVE N CEDAR RIVER N 1 S T S T BRONSON W AY N S 4TH ST N 3RD ST N 4TH ST N NEDRAG S EVA TTENRUBLOGAN AVE S SW 7TH ST GRADY WA Y S W N EVA YROTCAFMONSTER RD 5-50 5-51 N EVA SMAILLIW7-206 Triton Tower Two 7-207 Triton Tower Three From Seattle 5-08 Washington – Renton North 8th and Park Avenue North, Renton, WA 98055 N 5TH ST N 6TH ST N 8TH ST 5-45 Revised 03-09 Boeing North Bridge Boeing South Bridge 7-244 Rivertech Corporate Center HOUSER WAY BYPASS Copyright 2009© The Boeing Company. All rights reserved.PARK AVE N WELLS AVE N POWELL AVE SW NACHES AVE 4-95Shed 4-96GuardShack Employee gates AMS Turnstile gates Fence lines Boeing property General parking Restricted parking Bus stop Helistop 51 52 53 54 55 51 52 53 54 55 A B C D E F A B D E F C D44 D41 D4 D32 Figure 3 5.650.10.15.654003002001000-1000100200300400Total Settlement (in) 0.00 0.57 1.14 1.71 2.28 2.85 3.42 3.99 4.56 5.13 5.70max (stage): 5.65 inmax (all): 5.65 inAnalysis DescriptionSettlementCompanyS&EEDrawn ByC. J. ShinFile NameSurcharge 255x310 with pt84 ksfR4.s3zDate3/2/19ProjectApron D Expansion and Paint Hangar SETTLE3D 3.020 APPENDIX A FIELD EXPLORATION AND LOGS OF BORINGS We obtain the subsurface conditions at the site by the drilling of 9 soil test boring, B-1 through B-9. These borings were drilled on December 1 through 5, 2019. The locations of these borings are shown in Figure 2. The test borings were advanced using both truck-mounted drill rig. A representative from S&EE was present throughout the exploration to observe the drilling operations, log subsurface soil conditions, obtain soil samples, and to prepare descriptive geologic logs of the exploration. Soil samples were taken at 2.5- and 5-foot intervals in general accordance with ASTM D-1586, "Standard Method for Penetration Test and Split-Barrel Sampling of Soils" (1.4” I.D. sampler). The penetration test involves driving the samplers 18 inches into the ground at the bottom of the borehole with a 140 pounds hammer dropping 30 inches. The numbers of blows needed for the samplers to penetrate each 6 inches are recorded and are presented on the boring logs. The sum of the number of blows required for the second and third 6 inches of penetration is termed "standard penetration resistance" or the "N-value". In cases where 50 blows are insufficient to advance it through a 6 inches interval the penetration after 50 blows is recorded. The blow count provides an indication of the density of the subsoil, and it is used in many empirical geotechnical engineering formulae. The following table provides a general correlation of blow count with density and consistency. DENSITY (GRANULAR SOILS) CONSISTENCY (FINE-GRAINED SOILS) N-value < 4 very loose N-value < 2 very soft 5-10 loose 3-4 soft 11-30 medium dense 5-8 medium stiff 31-50 dense 9-15 stiff >50 very dense 16-30 very stiff >30 hard After drilling, the test borings were backfilled with bentonite chips and the surface is patched with quick set concrete. The boring logs are included in this appendix. A chart showing the Unified Soil Classification System is included at the end of this appendix. A groundwater monitoring well was installed in Borings B-1 and B-7. The well in B-1 has a one-inch diameter screen pipe from depths of 30 to 45 feet and solid pipe from 30 feet to the ground surface. The well in B-7 has a one-inch diameter screen pipe from depths of 15 to 30 feet and solid pipe from 15 feet to the ground surface. 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 20 30Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols25 35 40 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 40 50Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols45 55 60 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 60 70Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols65 75 80 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 80 90Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols85 95 100 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 100 110Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols105 115 120 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 120 130Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols125 135 140 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 140 150Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthJob No. 18181 USCS Symbols145 155 160 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 20 30Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols25 35 40 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 40 50Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols45 55 60 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 60 70Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols65 75 80 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 80 90Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols85 95 100 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 100 110Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols105 115 120 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 120 130Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols125 135 140 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 140 150Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthJob No. 18181 USCS Symbols145 155 160 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 4, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%)16 29 31 18 6 20 26 24 18 16 22 27 29 18 9 SP 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 20 30Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols25 35 40 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 40 50Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols45 55 60 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 60 70Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols65 75 80 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 80 90Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols85 95 100 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 100 110Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols105 115 120 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 120 130Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols125 135 140 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud Rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 140 150Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthJob No. 1818 USCS Symbols145 155 160 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Mud rotary advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 3, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%)20 37 35 18 6 24 29 38 18 12 20 26 30 18 14 SP 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 20 30Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthJob No. 18181 USCS Symbols25 35 40 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 5, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%)19 15 11 18 12 8 16 18 18 18 7 9 8 18 12 t 18 11 18 16 5 3 3 16 14 17 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) 0 10Depth (feet)Inches DrivenInches RecoveredBlows/6"Sample DepthSurface condition: Asphalt Job No. 1818 USCS Symbols5 15 20 Client: Drilling Method: Sampling Method: Drilling Date: Drilling Contractor: The Boeing Company Hollow stem auger advanced by truck-mount drill rig SPT sampler driven by 140-lb auto hammer December 1, 2018 Holocene DrillingDry Density (pcf)/Moisture Content (%)Fines Content (%) APPENDIX B LABORATORY TESTS Selected soil samples were transported to our sub-contracted soil laboratory, HWA in Bothell, WA for engineering property tests. The tests include sieve analyses, Atterberg Limits, and consolidation. The results are included in this appendix. 0 10 20 30 40 50 60 70 80 90 100 0.0010.010.1110 SYMBOL Gravel % 3"1-1/2"PERCENT FINER BY WEIGHT#4 #200 Sand % (SW-SM) Grayish brown, well graded SAND with silt and gravel (SP-SM) Very dark gray, poorly graded SAND with silt Fines % Coarse #60#40#20 Fine Coarse 14 30 GRAIN SIZE IN MILLIMETERS 50 SAMPLE 35.0 - 35.0 22.5 - 22.5 #10 30 CLASSIFICATION OF SOIL- ASTM D2487 Group Symbol and Name U.S. STANDARD SIEVE SIZES SAND 1 0.00050.005 CLAY B-1 B-7 SILT 3/4" GRAVEL 0.05 5/8" 70 #100 0.5 50 Medium Fine 3/8" 5 PI 90 10 % MC LL PL DEPTH ( ft.) PARTICLE-SIZE ANALYSIS OF SOILS METHOD ASTM D6913/D7928 49.4 86.9 11.2 11.9 39.3 1.2 2011-025 T300PROJECT NO.: HWAGRSZ 2011-025 T300.GPJ 1/7/19 FIGURE: MLT for Soil & Environmental Engineers, Inc. Apron D Expansion 0 10 20 30 40 50 60 0 20 40 60 80 100 % MC LL CL-ML MH SAMPLEPLASTICITY INDEX (PI)SYMBOL PL PI 50.0 - 50.0 120.0 - 120.0 23 24 36 33 LIQUID LIMIT, PLASTIC LIMIT AND PLASTICITY INDEX OF SOILS METHOD ASTM D4318 CL (CL) Dark gray, lean CLAY (CL) Dark gray, lean CLAY 2 15 13 CH CLASSIFICATION % Fines LIQUID LIMIT (LL) B-2 B-3 ML 38 37 DEPTH (ft) 2011-025 T300PROJECT NO.: HWAATTB 2011-025 T300.GPJ 1/7/19 FIGURE: MLT for Soil & Environmental Engineers, Inc. Apron D Expansion Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0 0.5 1 1.5 2 2.5 Applied Pressure - ksf 0.1 1 10Void Ratio0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 86.6 % 46.2 % 70.8 2.65 ML 1.413 Gray, SILT (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 3 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Source of Sample: B-1 Depth: 24 Figure Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0 0.5 1 1.5 2 2.5 Applied Pressure - ksf 0.1 1 10Percent Strain25 22 19 16 13 10 7 4 1 -2 -5 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 86.6 % 46.2 % 70.8 2.65 ML 1.413 Gray, SILT (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 4 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Source of Sample: B-1 Depth: 24 Figure Dial Reading vs. Time Project No.: Project: Source of Sample: B-1 Depth: 24 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 2.215 ft.2/day Ca = 0.001 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.550 ft.2/day Ca = 0.002 2011-025 T300 Apron D Expansion 1 0.13 ksf 0.0000 0.0026 0.0053 0.22 min. 2 0.25 ksf 0.0065 0.0079 0.0094 0.88 min. 5Dial Reading (in.)0.0065 0.0060 0.0055 0.0050 0.0045 0.0040 0.0035 0.0030 0.0025 0.0020 0.0015 Elapsed Time (min.) 0.1 1 10 100 1000 Dial Reading (in.)0.0106 0.0102 0.0098 0.0094 0.0090 0.0086 0.0082 0.0078 0.0074 0.0070 0.0066 Elapsed Time (min.) 0.1 1 10 100 t 4t FigureHWA GeoSciences Inc. Dial Reading vs. Time Project No.: Project: Source of Sample: B-1 Depth: 24 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.599 ft.2/day Ca = 0.003 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.374 ft.2/day Ca = 0.004 2011-025 T300 Apron D Expansion 3 0.50 ksf 0.0114 0.0140 0.0167 0.80 min. 4 1.00 ksf 0.0220 0.0263 0.0307 1.25 min. 6Dial Reading (in.)0.021 0.020 0.019 0.018 0.017 0.016 0.015 0.014 0.013 0.012 0.011 Elapsed Time (min.) 0.1 1 10 100 1000 t 4t Dial Reading (in.)0.0360 0.0345 0.0330 0.0315 0.0300 0.0285 0.0270 0.0255 0.0240 0.0225 0.0210 Elapsed Time (min.) 0.1 1 10 100 1000 t 4t FigureHWA GeoSciences Inc. Dial Reading vs. Time Project No.: Project: Source of Sample: B-1 Depth: 24 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.209 ft.2/day Ca = 0.006 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.145 ft.2/day Ca = 0.010 2011-025 T300 Apron D Expansion 5 2.00 ksf 0.0376 0.0446 0.0517 2.15 min. 6 4.00 ksf 0.0594 0.0683 0.0773 2.94 min. 7Dial Reading (in.)0.0600 0.0575 0.0550 0.0525 0.0500 0.0475 0.0450 0.0425 0.0400 0.0375 0.0350 Elapsed Time (min.) 0.1 1 10 100 1000 10000 t 4t Dial Reading (in.)0.089 0.086 0.083 0.080 0.077 0.074 0.071 0.068 0.065 0.062 0.059 Elapsed Time (min.) 0.1 1 10 100 1000 t 4t FigureHWA GeoSciences Inc. Dial Reading vs. Time Project No.: Project: Source of Sample: B-1 Depth: 24 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.169 ft.2/day Ca = 0.013 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.124 ft.2/day Ca = 0.011 2011-025 T300 Apron D Expansion 7 8.00 ksf 0.0863 0.1003 0.1144 2.34 min. 8 16.00 ksf 0.1275 0.1457 0.1639 2.87 min. 8Dial Reading (in.)0.135 0.130 0.125 0.120 0.115 0.110 0.105 0.100 0.095 0.090 0.085 Elapsed Time (min.) 0.1 1 10 100 1000 t 4t Dial Reading (in.)0.20 0.19 0.18 0.17 0.16 0.15 0.14 0.13 0.12 0.11 0.10 Elapsed Time (min.) 0.1 1 10 100 1000 10000 t 4t FigureHWA GeoSciences Inc. Dial Reading vs. Time Project No.: Project: Source of Sample: B-1 Depth: 24 Load No.= Load= D0 = D50 = D100 = T50 = Cv @ T50 0.199 ft.2/day Ca = 0.015 2011-025 T300 Apron D Expansion 9 32.00 ksf 0.1711 0.1909 0.2108 1.59 min. 9Dial Reading (in.)0.230 0.225 0.220 0.215 0.210 0.205 0.200 0.195 0.190 0.185 0.180 Elapsed Time (min.) 0.1 1 10 100 1000 t 4t FigureHWA GeoSciences Inc. Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0 1 2 3 4 5 Applied Pressure - ksf 0.1 1 10Void Ratio0.68 0.72 0.76 0.80 0.84 0.88 0.92 0.96 1.00 1.04 1.08 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 92.5 % 34.9 % 85.1 2.65 ML 1.000 Olive gray, SILT with sand (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 10 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Source of Sample: B-1 Depth: 41.5 Figure Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0 1 2 3 4 5 Applied Pressure - ksf 0.1 1 10Percent Strain17 15 13 11 9 7 5 3 1 -1 -3 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 92.5 % 34.9 % 85.1 2.65 ML 1.000 Olive gray, SILT with sand (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 11 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Source of Sample: B-1 Depth: 41.5 Figure Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0.8 1.1 1.4 1.7 2 2.3 Applied Pressure - ksf 0.1 1 10Void Ratio0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 88.7 % 48.2 % 70.7 2.65 ML 1.439 Olive gray, SILT (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 12 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Depth: 11.5 Figure Tested By: DW Checked By: SEG CONSOLIDATION TEST REPORT Cv(ft.2/day)0.8 1.1 1.4 1.7 2 2.3 Applied Pressure - ksf 0.1 1 10Percent Strain27 24 21 18 15 12 9 6 3 0 -3 Natural Dry Dens.LL PI Sp. Gr. USCS AASHTO Initial Void Saturation Moisture (pcf)Ratio 88.7 % 48.2 % 70.7 2.65 ML 1.439 Olive gray, SILT (ML) 2011-025 Soil & Environmental Engineers, Inc. Apron D Expansion 13 MATERIAL DESCRIPTION Project No.Client:Remarks: Project: Depth: 11.5 Figure Appendix H Flow Splitter Calculations PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN STEPS STEP 1:Determine the Water Quality flow rate STEP 2:Determine the head (h3) required to pass the water quality flow rate through the treatment site outlet. STEP 3:Set the invert of the treatment site outlet pipe so that h3 is equal to distance from the top of the weir to the center of the treatment site outlet pipe for the WQ storm event (h1 will equal zero). STEP 4:Calculate additional storm events to determine additional treatment site flow based on increases in the Maximum Water Surface Elevation STEP 5:Check the head (h2) required to pass the bypass flow out the outlet pipe The invert for the treatment site outlet pipe is determined by the Maximum Water Surface Elevation. The Maximum Water Surface Elevation will fluctuate depending on the Design Storm Event flow. Therefore, the amount of head contributing to the treatment site outlet flow will also vary. The treatment site outlet pipe invert will be set to convey the entire WQ design storm without any bypass over the weir. The Maximum Water Surface Elevation will be equal to the weir elevation. Any flow above the WQ design storm flow will become bypass flow. With the treatment site outlet pipe invert elevation determined by the Maximum Water Surface Elevation during the WQ storm event, flow to the treatment site will increase with greater storm events. For example, the 100-year storm event has been determined to contribute 36cfs and raise the Maximum Water Surface Elevation in the Flow Splitter structure. The increase in the Maximum Water Surface Elevation will increase the head on the treatment site outlet pipe and thus increase the flow to the treatment site. North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate =0.31 cfs WQ Flow Rate =0.31 cfs Bypass Flow Rate =0.00 cfs Structure Information: Structure Note CB212 Manhole Size 60 in Rim 25.89 Invert Elev - IN 14.31 Pipe Size =18 in Invert Elev - OUT 12.61 Pipe Size =18 in Weir Elev 14.31 Baffle Wall Elev 15.31 STEP 1:Determine the Maximum Water Surface Elevation Determine the Head required to pass the BYPASS FLOW RATE over the Weir Weir equation:Q = C L H3/2 Q =0.00 cfs Bypass flow C =3.27 Weir coefficient H =Flow depth over weir, ft L =Weir width, ft (Given below) Given L values, adjust H values until the Combined Flow Rate equals the BYPASS FLOW RATE L, ft H, ft Q, cfs h1 =0.00 ft Weir 4.7 0.00 0.00 Baffle Wall 1 0.00 0.00 (Weir elevation is 1' below the baffle wall elevation) Combined Flow 0.00 cfs Therefore the Maximum Water Surface Elevation is the Weir elevation plus the Head required to pass the BYPASS FLOW RATE over the weir Max Water Surface Elev =14.31 Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in Q =0.00 cfs =>h2 =0.00 ft C =0.62 A =1.77 sf OK Pipe Diam. = Water Quality Storm Event North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 g =32.20 ft/s2 STEP 2:Determine the Head required to pass the WATER QUALITY FLOW to the Treatment Facility Using the Orifice Equation:Q=CA(2gh)1/2 or h = (Q/CA)2 1/2g 4 in Q =0.31 cfs =>h3 =0.51 ft C =0.62 A =0.09 sf g =32.20 ft/s2 STEP 3:Set the Water Quality Outlet Pipe Invert Set the Water Quality Outlet Pipe Invert the distance (h 3 + 1/2 Water Quality Outlet Pipe Diameter) BELOW the Maximum Water Surface Elevation Water Quality Outlet Pipe Invert Elev =13.63 Pipe Diam. = North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q2) =1.31 cfs 2 yr 24 Hr Flow Rate Structure Information: Structure Note CB212 Manhole Size 60 in Rim Elevation 25.89 Invert Elevation - IN 14.31 Pipe Size =18 in Invert Elevtion - OUT 12.61 Pipe Size =18 in Weir Elevation 14.31 Weir Length 4.70 ft Baffle Wall Elevation 15.31 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 13.63 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q2) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >14.47 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 1.31 cfs >1.31 Bypass Flow (Qb)h1 =0.16 Weir equation:Qb = C L (h1)3/2 h3 =0.67 Qb =Bypass flow (cfs)Treatment Site cfs =0.35 C =3.27 (Weir coefficient)Bypass cfs =0.96 h1 =Head over weir, ft L =Weir/baffle wall length, ft 2-Year Storm Event North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 2-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =0.96 cfs =>h2 =0.01 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q10) =1.89 cfs 10 yr 24 Hr Flow Rate Structure Information: Structure Note CB212 Manhole Size 60 in Rim Elevation 25.89 Invert Elevation - IN 14.31 Pipe Size =18 in Invert Elevtion - OUT 12.61 Pipe Size =18 in Weir Elevation 14.31 Weir Length 4.70 ft Baffle Wall Elevation 15.31 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 13.63 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q10) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >14.52 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 1.89 cfs >1.89 Bypass Flow (Qb)h1 =0.21 Weir equation:Qb = C L (h1)3/2 h3 =0.72 Qb =Bypass flow (cfs)Treatment Site cfs =0.37 C =3.27 (Weir coefficient)Bypass cfs =1.52 h1 =Head over weir, ft L =Weir/baffle wall length, ft 10-Year Storm Event North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 10-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =1.52 cfs =>h2 =0.03 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q100) =2.66 cfs 100 yr 24 Hr Flow Rate from Stormdrain Analysis Structure Information: Structure Note CB212 Manhole Size 60 in Rim Elevation 25.89 Invert Elevation - IN 14.31 Pipe Size =18 in Invert Elevtion - OUT 12.61 Pipe Size =18 in Weir Elevation 14.31 Weir Length 4.70 ft Baffle Wall Elevation 15.31 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 13.63 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q100) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >14.59 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 2.66 cfs >2.66 Bypass Flow (Qb)h1 =0.28 Weir equation:Qb = C L (h1)3/2 h3 =0.79 Qb =Bypass flow (cfs)Treatment Site cfs =0.39 C =3.27 (Weir coefficient)Bypass cfs =2.28 h1 =Head over weir, ft L =Weir/baffle wall length, ft 100-Year Storm Event North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 100-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =2.28 cfs =>h2 =0.07 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = North Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Stalls JOB:13726.16 DATE: 6-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: Structure Information: Structure Note CB212 Manhole Size 60 in. Rim Elevation 25.89 Invert Elevation - IN 14.31 Pipe Size =18 Invert Elevation - OUT 12.61 Pipe Size =18 Weir Elevation 14.31 Baffle Wall Elevation 15.31 WQ Outlet Invert Elevation 13.63 Orifice Size 4 in. 24 Hour Design Storm Event Design Flow Rate (cfs)WQ Flow Rate (cfs) Head Required to pass WQ Flow (ft) Head over weir per design storm flow rate (h1) Maximum water surface elevation per design storm Head over the treament site outlet (h3) Total flow rate to bypass per design storm Total flow rate to downstream facility per design storm WQ Flow 0.31 0.31 0.51 0.00 14.31 0.51 0.00 0.31 2-year 1.31 0.31 0.51 0.16 14.47 0.67 0.96 0.35 10-year 1.89 0.31 0.51 0.21 14.52 0.72 1.52 0.37 100-year 2.66 0.31 0.51 0.28 14.59 0.79 2.28 0.39 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN STEPS STEP 1:Determine the Water Quality flow rate STEP 2:Determine the head (h3) required to pass the water quality flow rate through the treatment site outlet. STEP 3:Set the invert of the treatment site outlet pipe so that h3 is equal to distance from the top of the weir to the center of the treatment site outlet pipe for the WQ storm event (h1 will equal zero). STEP 4:Calculate additional storm events to determine additional treatment site flow based on increases in the Maximum Water Surface Elevation STEP 5:Check the head (h2) required to pass the bypass flow out the outlet pipe The invert for the treatment site outlet pipe is determined by the Maximum Water Surface Elevation. The Maximum Water Surface Elevation will fluctuate depending on the Design Storm Event flow. Therefore, the amount of head contributing to the treatment site outlet flow will also vary. The treatment site outlet pipe invert will be set to convey the entire WQ design storm without any bypass over the weir. The Maximum Water Surface Elevation will be equal to the weir elevation. Any flow above the WQ design storm flow will become bypass flow. With the treatment site outlet pipe invert elevation determined by the Maximum Water Surface Elevation during the WQ storm event, flow to the treatment site will increase with greater storm events. For example, the 100-year storm event has been determined to contribute 36cfs and raise the Maximum Water Surface Elevation in the Flow Splitter structure. The increase in the Maximum Water Surface Elevation will increase the head on the treatment site outlet pipe and thus increase the flow to the treatment site. South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate =0.46 cfs WQ Flow Rate =0.46 cfs Bypass Flow Rate =0.00 cfs Structure Information: Structure Note VVT-002 Manhole Size 96 in Rim 27.99 Invert Elev - IN 15.84 Pipe Size =12 in Invert Elev - OUT 14.14 Pipe Size =18 in Weir Elev 15.84 Baffle Wall Elev 16.84 STEP 1:Determine the Maximum Water Surface Elevation Determine the Head required to pass the BYPASS FLOW RATE over the Weir Weir equation:Q = C L H3/2 Q =0.00 cfs Bypass flow C =3.27 Weir coefficient H =Flow depth over weir, ft L =Weir width, ft (Given below) Given L values, adjust H values until the Combined Flow Rate equals the BYPASS FLOW RATE L, ft H, ft Q, cfs h1 =0.00 ft Weir 4.7 0.00 0.00 Baffle Wall 1 0.00 0.00 (Weir elevation is 1' below the baffle wall elevation) Combined Flow 0.00 cfs Therefore the Maximum Water Surface Elevation is the Weir elevation plus the Head required to pass the BYPASS FLOW RATE over the weir Max Water Surface Elev =15.84 Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in Q =0.00 cfs =>h2 =0.00 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Water Quality Storm Event South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 STEP 2:Determine the Head required to pass the WATER QUALITY FLOW to the Treatment Facility Using the Orifice Equation:Q=CA(2gh)1/2 or h = (Q/CA)2 1/2g 4 in Q =0.46 cfs =>h3 =1.12 ft C =0.62 A =0.09 sf g =32.20 ft/s2 STEP 3:Set the Water Quality Outlet Pipe Invert Set the Water Quality Outlet Pipe Invert the distance (h 3 + 1/2 Water Quality Outlet Pipe Diameter) BELOW the Maximum Water Surface Elevation Water Quality Outlet Pipe Invert Elev =14.55 Pipe Diam. = South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q2) =1.89 cfs 2 yr 24 Hr Flow Rate Structure Information: Structure Note VVT-002 Manhole Size 96 in Rim Elevation 27.99 Invert Elevation - IN 15.84 Pipe Size =12 in Invert Elevtion - OUT 14.14 Pipe Size =18 in Weir Elevation 15.84 Weir Length 4.70 ft Baffle Wall Elevation 16.84 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 14.55 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q2) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >16.04 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 1.89 cfs >1.89 Bypass Flow (Qb)h1 =0.20 Weir equation:Qb = C L (h1)3/2 h3 =1.32 Qb =Bypass flow (cfs)Treatment Site cfs =0.50 C =3.27 (Weir coefficient)Bypass cfs =1.40 h1 =Head over weir, ft L =Weir/baffle wall length, ft 2-Year Storm Event South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 2-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =1.40 cfs =>h2 =0.03 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q10) =2.73 cfs 10 yr 24 Hr Flow Rate Structure Information: Structure Note VVT-002 Manhole Size 96 in Rim Elevation 27.99 Invert Elevation - IN 15.84 Pipe Size =12 in Invert Elevtion - OUT 14.14 Pipe Size =18 in Weir Elevation 15.84 Weir Length 4.70 ft Baffle Wall Elevation 16.84 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 14.55 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q10) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >16.12 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 2.73 cfs >2.73 Bypass Flow (Qb)h1 =0.27 Weir equation:Qb = C L (h1)3/2 h3 =1.40 Qb =Bypass flow (cfs)Treatment Site cfs =0.51 C =3.27 (Weir coefficient)Bypass cfs =2.22 h1 =Head over weir, ft L =Weir/baffle wall length, ft 10-Year Storm Event South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 10-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =2.22 cfs =>h2 =0.06 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN Flow Rate Information: Design Flow Rate (Q100) =3.84 cfs 100 yr 24 Hr Flow Rate from Stormdrain Analysis Structure Information: Structure Note VVT-002 Manhole Size 96 in Rim Elevation 27.99 Invert Elevation - IN 15.84 Pipe Size =12 in Invert Elevtion - OUT 14.14 Pipe Size =18 in Weir Elevation 15.84 Weir Length 4.70 ft Baffle Wall Elevation 16.84 Effective Baffle Wall Length 1.00 ft Trtmt Site Outlet Invert Elev 14.55 Pipe Size =4 in Given the treatment site outlet invert elevation and the weir elevation, use the orifice equation and the weir equation to determine the Maximum Water Surface Elevation for the design storm. Treatment Site Flow (Qt) + Bypass Flow (Qb) = Design Flow Rate (Q100) (See attached page for Flow Splitter diagram) Treatment Site Flow (Qt) Orifice Equation:Qt=CA(2gh3)1/2 or h3 = (Qt/CA)2 1/2g Qt =Treatment Site Flow (cfs) C =0.62 orifice coefficient Adjust Max S.W. Elev >16.20 A =0.09 orifice area, sf g =32.20 gravity, ft/s2 to match the Design Flow Rate h3 =Head over treatment site outlet pipe, ft 3.84 cfs >3.84 Bypass Flow (Qb)h1 =0.36 Weir equation:Qb = C L (h1)3/2 h3 =1.48 Qb =Bypass flow (cfs)Treatment Site cfs =0.53 C =3.27 (Weir coefficient)Bypass cfs =3.31 h1 =Head over weir, ft L =Weir/baffle wall length, ft 100-Year Storm Event South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: FLOW SPLITTER DESIGN 100-Year Storm Event Check the Head required to pass the BYPASS FLOW RATE through the outlet pipe 18 in 1.70 ft Q =3.31 cfs =>h2 =0.14 ft C =0.62 A =1.77 sf OK g =32.20 ft/s2 Pipe Diam. = Min Available head = South Flow Splitter - 4inch_12-05-2019.xls 6/6/02 PROJECT: Boeing Apron E - Site and Paint Hangar JOB:13726.16 DATE: 10-Dec-19 SUBJECT: Flow Splitter Design BY:JTS SHEET: Structure Information: Structure Note VVT-002 Manhole Size 96 in. Rim Elevation 27.99 Invert Elevation - IN 15.84 Pipe Size =12 Invert Elevation - OUT 14.14 Pipe Size =18 Weir Elevation 15.84 Baffle Wall Elevation 16.84 WQ Outlet Invert Elevation 14.55 Orifice Size 4 in. 24 Hour Design Storm Event Design Flow Rate (cfs)WQ Flow Rate (cfs) Head Required to pass WQ Flow (ft) Head over weir per design storm flow rate (h1) Maximum water surface elevation per design storm Head over the treament site outlet (h3) Total flow rate to bypass per design storm Total flow rate to downstream facility per design storm WQ Flow 0.46 0.46 1.12 0.00 15.84 1.12 0.00 0.46 2-year 1.89 0.46 1.12 0.20 16.04 1.32 1.40 0.50 10-year 2.73 0.46 1.12 0.27 16.12 1.40 2.22 0.51 100-year 3.84 0.46 1.12 0.36 16.20 1.48 3.31 0.53