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HomeMy WebLinkAboutRS_CSWPPP_FINAL_20181115 Civil Engineers ● Structural Engineers ● Landscape Architects ● Community Planners ● Land Surveyors ESC Plan for Construction Stormwater Pollution Prevention PREPARED FOR: HHJ Architects, PLLC 601 Saint Helens Avenue Tacoma, WA 98402 Contact: Chee Tung PROJECT: Walker Auto Dealership 3400 East Valley Road Renton, WA 98057 2180100.10 PREPARED BY: Matt Whittlesey, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: August 2018 Revised September 2018 ESC Plan for Construction Stormwater Pollution Prevention PREPARED FOR: HHJ Architects, PLLC 601 Saint Helens Avenue Tacoma, WA 98402 Contact: Chee Tung PROJECT: Walker Auto Dealership 3400 East Valley Road Renton, WA 98057 2180100.10 PREPARED BY: Matt Whittlesey, EIT Project Engineer REVIEWED BY: Scott T. Kaul, PE, LEED AP Project Manager J. Matthew Weber, PE Principal DATE: August 2018 Revise September 2018 I hereby state that this ESC Plan for Construction Stormwater Pollution Prevention for the Walker Auto Dealership project has been prepared by me or under my supervision, and meets the standard of care and expertise that is usual and customary in this community for professional engineers. I understand that City of Renton does not and will not assume liability for the sufficiency, suitability, or performance of drainage facilities prepared by me. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Table of Contents Section Page 1.0 Purpose ........................................................................................................................................... 1 2.0 Conditions of Use .......................................................................................................................... 2 3.0 Existing Site Conditions ................................................................................................................ 2 3.1 Existing Cover ..................................................................................................................... 2 3.2 Topography and Design ...................................................................................................... 2 3.3 Adjacent Areas .................................................................................................................... 2 4.0 ESC Plan Analysis and Design (Part A) ....................................................................................... 3 4.1 ESC Measures .................................................................................................................... 3 4.1.1 Clearing Limits ....................................................................................................... 3 4.1.2 Cover Measures ..................................................................................................... 3 4.1.3 Perimeter Protection .............................................................................................. 4 4.1.4 Traffic Area Stabilization ........................................................................................ 4 4.1.5 Sediment Retention ............................................................................................... 4 4.1.6 Surface Water Collection ....................................................................................... 4 4.1.7 Dewatering Control ................................................................................................ 4 4.1.8 Dust Control ........................................................................................................... 5 4.1.9 Flow Control ........................................................................................................... 5 4.1.10 Control Pollutants ................................................................................................... 5 4.1.11 Protect Existing and Proposed Flow Control BMPs ............................................... 5 4.1.12 Maintain BMPs ....................................................................................................... 5 4.1.13 Manage the Project ................................................................................................ 5 4.2 Erosion Problem Areas ....................................................................................................... 6 5.0 Stormwater Pollution Prevention and Spill (SWPPS) Plan Design (Part B) ............................. 6 5.1 Pollution and Spill Prevention Source Controls and BMPs ................................................. 6 5.2 Responsible Personnel and Contact Information ............................................................... 7 5.3 Pollution and Spill Prevention Worksheets ......................................................................... 7 5.4 Disposal Methods ................................................................................................................ 7 6.0 ESC Performance and Compliance Provisions .......................................................................... 7 6.1 ESC Supervisor ................................................................................................................... 7 6.2 Monitoring of Discharges .................................................................................................... 8 ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 6.3 ESC Performance ............................................................................................................... 8 6.4 Flexible Compliance ............................................................................................................ 8 6.5 Roads and Utilities Compliance .......................................................................................... 8 6.6 Alternative and Experimental Measures ............................................................................. 8 7.0 ESC Implementation Requirements ............................................................................................. 8 7.1 Wet Season Requirements ................................................................................................. 8 7.2 Critical Areas Restriction ..................................................................................................... 9 7.3 Maintenance Requirement .................................................................................................. 9 7.4 Construction Sequence ..................................................................................................... 10 7.5 Final Stabilization .............................................................................................................. 11 7.6 NPDES Requirements ...................................................................................................... 11 7.7 Forest Practice Permit Requirements ............................................................................... 11 8.0 Construction Schedule ................................................................................................................ 11 ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendices Appendix A Exhibits A-1 ............. Vicinity Map A-2 ............. Existing Conditions Map C0.1 ........... Cover Sheet (Early Grading Permit) C0.2 ........... Existing Conditions (Topographic Survey) C0.3 ........... Test Pit and Excavation Map / Phasing Plan C1.1 ........... Demo, Excavation, and Clean-Up Plan C2.1 ........... Rough Grading and TESC Plan C3.1 ........... TESC Notes and Details C3.2 ........... TESC Notes an Details Appendix B Select King County Source Control BMPs Appendix C Inspection and Maintenance Report Forms Appendix D Geotechnical Report Migizi Group, Inc., April 27, 2018 Appendix E Sediment Pond Sizing ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 1 2180100.10 1.0 Purpose In 1972, Congress passed the Federal Water Pollution Control Act (FWPCA), also known as the Clean Water Act (CWA), to restore and maintain the quality of the nation's waterways. The ultimate goal was to ensure that rivers and streams were fishable, swimmable, and drinkable. In 1987, the Water Quality Act (WQA) added provisions t o the CWA that allowed the Environmental Protection Agency (EPA) to govern stormwater discharges from construction sites. In 1998, the EPA published the final notice for General Permits for Storm Water Discharges from Construction Activities Disturbing 5 Acres or Greater (63 Federal Register 7898, February 14, 1998). The general permit includes provisions for development of a Stormwater Pollution Prevention Plan (SWPPP) to maximize the potential benefits of pollution prevention, and sediment and erosion control measures at construction sites. Development, implementation, and maintenance of the Construction SWPPP will provide the selected General Contractor with the framework for reducing soil erosion and minimizing pollutants in stormwater during construct ion. The Construction SWPPP will:  Define the characteristics of the site and the type of construction that will occur.  Describe the practices that will be implemented to control erosion, and the release of pollutants in stormwater.  Create an implementation schedule to ensure that the practices described in this Construction SWPPP are in fact implemented; and to evaluate the plan's effectiveness in reducing erosion, sediment, and pollutant levels in stormwater discharged from the site.  Describe the final stabilization/termination design to minimize erosion and prevent stormwater impacts after construction is complete. This Construction SWPPP includes the following:  Identification of the Construction SWPPP Coordinator with a description of this person's duties.  Identification of the Stormwater Pollution Prevention Team (SWPP Team) that will assist in implementation of the Construction SWPPP during construction.  Description of the existing site conditions, including existing land use for the site, soil types at the site, as well as the location of surface waters that are located on or next to the site.  Identification of the body or bodies of water that will receive runoff from the construction site, including the ultimate body of water that receives the stormwater.  Identification of drainage areas and potential stormwater contaminants.  Description of stormwater management controls and various Best Management Practices (BMPs) necessary to reduce erosion, sediment, and pollutants in stormwater discharge.  Description of the facility monitoring plan, and how controls will be coordinated with construction activities.  Description of the implementation schedule and provisions for amendment of the plan. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2 2180100.10 2.0 Conditions of Use This report accompanies the early clear and grade plans and documents for the Walker Auto Dealership project located at 3400 East Valley Road in the city of Renton. The site is located on Parcel No. 3023059067. The future project proposes an approximately 48,000-square foot auto dealership, with associated parking and drive aisles. The project site is approximately 5.65 acres in size. Due to the existence of onsite contaminated soils and previous development of a wetland buffer this early scope of work is proposed to remove contamination from the site below state allowable levels, restore and plant the wetland buffer to 75.0’, and grade and stabilize the site. The primary goal of this work is to enter the voluntary clean-up program with ecology and receive a No Further Action letter. Stormwater management is to comply with the 2016 King County Surface Water Design Manual (KCSWDM), as amended by the City of Renton, the 2016 City of Renton Surface Water Design Manual (CRSWDM). 3.0 Existing Site Conditions 3.1 Existing Cover The site sits on a 5.65-acre parcel near the intersection of East Valley Road and SW 34th Street. The site is bordered to the west by East Valley Road, to the south by an industrial vehicle storage area, to the east by SR 167, and to the north by an RV storage lot. The site is currently vacant, and was previously an auto wrecking yard. The site contains an asphalt driveway and parking area and an existing office building. The remaining portion of the site is a gravel storage area. Remaining contamination from the previous use as an auto wrecking yard will be remediated through Ecology’s Voluntary Cleanup Program. Cleanup of the site will occur during the early clear and grade activities. There is a wetland located directly east of the site. A Critical Areas Report by PBS dated April 2018 classifies the wetland as Category III. The wetland is located mostly within Washington State Department of Transportation (WSDOT) right-of-way. The proposed onsite wetland buffer is 75 feet. Restoration of the wetland buffer will be part of the early clear and grade work. Restoration of the offsite wetland will be completed under the direction of WSDOT. 3.2 Topography and Design The site is relatively flat. Runoff from the existing site either drains to the depression in the southwest corner of the site that was previously pumped to East Valley Road or drains to the wetland offsite in WSDOT ROW. This early grading plan will generally match the two existing basins onsite. 3.3 Adjacent Areas The site is bordered to the west by East Valley Road, to the south by an industrial vehicle storage area, to the east by SR 167, and to the north by an RV storage lot. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 3 2180100.10 4.0 ESC Plan Analysis and Design (Part A) 4.1 ESC Measures The purpose of this section is to describe how each of the 13 erosion and sediment control (ESC) measures has been addressed and to identify the type and location of BMPs used to satisfy the required measure. 4.1.1 Clearing Limits Clearing limits are identified on the plans. Prior to beginning land disturbing activities, clearing limits will be marked with flagging (BMP D.2.1.1) or high visibility plastic or metal fence (BMP D.2.1.1.1). 4.1.2 Cover Measures Because source control is the most important form of erosion control, construction practices must adhere to strict cover requirements. 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:  Mulching (BMP D.2.1.2.2)  Plastic Covering (BMP D.2.1.2.4)  Temporary and Permanent Seeding (BMP D.2.1.2.6) More specifically, during the period of May 1 through September 30, the Contractor will not be allowed to leave soils unprotected for more than seven days, and immediate seeding will be required for areas brought to finish grade with no further work planned for the next 30 days. Areas to be paved may be armored with crushed rock subbase in place of other stabilizing measures. The area of clearing will be limited to the amount that can be stabilized by September 30 of that year. During the period of October 1 through April 30, all disturbed soil areas will be covered or stabilized within two days or 24 hours when a major storm even is predicted. Cover measures may include mulching, netting, plastic sheeting, erosio n control blankets, or free draining material. The extent of clearing shall be limited to the amount of land that can be covered or stabilized within 24 hours. Soil stockpiles shall be stabilized by plastic covering or surrounded by filter fabric fence. The Contractor has the option of providing all required material for cover measures onsite at all times, or preparing a plan of action to submit to the City of Renton. A plan of action shall contain the following:  Contractor’s name, address, phone number, and emergency phone number.  Alternate contact with above information.  Clearly defined plan of action designed to prevent offsite migration of sediments, which will be implemented in the event that a major storm is predicted or offsite erosion is observed by the Contractor, his/her employees, or the City.  Description of materials to be used for cover and means by which it will be placed. List equipment to be used or number of personnel anticipated to be used to spread material. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 4 2180100.10  Vendor or supplier of materials used; list two alternates and include phone numbers.  Means and timeframe for cleanup of any materials that escape offsite and for repairs to the natural system if damages have occurred. In order for the ESC facilities to function properly, they m ust be maintained and sediment removed on a regular basis. Inspection and sediment removal shall be performed on all ESC facilities, as described in the inspection schedule located in Section 7.3 of this report. 4.1.3 Perimeter Protection Perimeter protection to filter sediment from sheet wash shall be located downslope of all disturbed areas and shall be installed prior to upslope grading. Filter fabric fencing (BMP D.2.1.3.1) will be required around the south, north, east, and west edges of the site and around stockpile areas to prevent sediment-laden stormwater from being transported offsite. During the wet season, 50 linear feet of filter fabric fencing per acre will be required. 4.1.4 Traffic Area Stabilization A stabilized construction entrance shall be insta lled as the first step of clearing and grading. The stabilized construction entrance (BMP D.2.1.4.1) will be used to prevent the transport of sediment onto the adjacent paved surfaces. If sediment is transported onto the road surface, the road shall be cleaned each day by sweeping or vacuuming prior to washing. Sediment removal by washing alone will not be allowed. If sediment is tracked from the site, the City may require stabilization of internal roads and car parking areas to contain the sediment (BMP D.2.1.4.2) or require the installation of a wheel wash basin (BMP D.2.1.4.3). 4.1.5 Sediment Retention 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.3.5.3) will be implemented for all drainage inlets and culverts that could potentially be impacted by sediment-laden runoff on and near the project site, including offsite catch basins located downstream of the project site. Storm drain inlet sediment protection will prevent coarse sediment from entering the drainage system prior to permanent stabilization of the disturbed areas. 4.1.6 Surface Water Collection Interceptor swales or dikes (BMP D.2.1.6.1) will be installed at the top of all slopes in excess of 3H:1V and greater than 20 feet of elevation change. Outlet protection (BMP D.2.1.6.5) is required at the outlets of all ponds, pipes, ditches, or other approved conveyances, and where runoff is conveyed to natural or m anmade drainage features such as a stream, wetland, lake, or ditch. 4.1.7 Dewatering Control During the initial phase of work, the site will be excavated in phases to limit soil disturbance and prevent contaminated stormwater from leaving the site. A baker tank system will be onsite to store all dewatering water from active excavations. The Baker Tank treatment system will discharge to the King County Sewer under an approved discharge permit. In the event that the Baker Treatment system does not provide adequate treatment levels under the permit the ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 5 2180100.10 contractor shall be responsible to have the stormwater / dewatering disposed by an authorized facility. 4.1.8 Dust Control 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. Water shall be used on exposed soils by spraying until wet, but runoff shall not be generated by spraying. Exposed areas shall be resprayed as needed. Oil shall not be used for dust control. 4.1.9 Flow Control Perimeter controls along with the Baker Tanks will control stormwater during the initial clean-up phase of work. Unworked portions of the site are currently impervious graveled storage yard that discharge off-site. As the cleanup progresses and the site is re-graded and stabilized with rock and straw mulch additional controls will be installed including interceptor swales along the perimeter to collect surface runoff and route it to onsite temporary sediment traps in the southwest and northeast corners of the site. The southwest sediment trap will have a riser structure with a discharge to the storm network in East Valley Road. The northeast sediment trap will discharge to a ditch that will empty into the offsite wetland. See Appendix E for sediment trap sizing. 4.1.10 Control Pollutants Stormwater Pollution Prevention and Spill (SWPPS) measures are required to prevent, reduce, or eliminate the discharge of pollutants to onsite or adjacent stormwater systems or watercourses for construction-related activities. Section 5.0 identifies these SWPPS measures. This site has contaminated soils. Soil remediation will be conducted in accordance with Stemen Environmental Voluntary Clean Up Scope of work (dated April 23, 2018) and the Departm ent of Ecology NPDES Permit requirements. A No Further Action Letter will be obtained prior to constructing the future development. 4.1.11 Protect Existing and Proposed Flow Control BMPs Protection measures shall be applied/installed and maintained to prevent ad verse impacts to areas of proposed flow control BMPs within the project site. There are no known existing flow control BMPs located on the project site. The contractor is responsible for protecting flow control BMPs. 4.1.12 Maintain BMPs Protection measures, per BMP D.2.1.11, shall be maintained to assure continued performance of their intended function and protect other disturbed areas of the project. There are no known existing flow control BMPs located on the project site. The Contractor is responsible for maintaining all temporary and permanent BMPs. 4.1.13 Manage the Project Coordination and timing of site development activities relative to ESC concerns (Section D.2.4 of the CRSWDM) and timely inspection, maintenance, and update of protective measures ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 6 2180100.10 (Section D.2.3 of the CRSWDM) are necessary to effectively manage the project and assure the success of protective ESC and SWPPS design and implementation. PBS Environmental will be the CESCL for the project to ensure proper maintenance of erosion control BMPs, discharge of stormwater to acceptable levels in accordance with the NPDES permit, and maintaining and updating the onsite SWPPP. 4.2 Erosion Problem Areas The erosion potential of the site soils is moderate to low, as there are no known historic erosion problems within or around the project site. Refer to Appendix B for recommended King County Source Control BMPs. 5.0 Stormwater Pollution Prevention and Spill (SWPPS) Plan Design (Part B) The Stormwater Pollution Prevention and Spill (SWPPS) Plan includes three elements: a site plan (Sheets C1.1, C2.1), provided in Appendix A), a pollution prevention report (this document), and a spill prevention and cleanup report. The spill prevention and cleanup report includes identifying the expected sources of potential pollution and spills that may occur during construction, and works to develop a plan to prevent pollution and spills. It also develops a plan to mitigate spills that may occur. The SWPPS Plan will be kept onsite at all times during construction. The General Contractor will be responsible to ensure that subcontractors are aware of the SWPPS Plan, and a form or record will be provided stating that all subcontractors have read and agree to the SWPPS Plan. An employee training worksheet is provided for the Contractor’s use (see Appendix C). A SWPPS Site Plan has been submitted with the civil engineering plans and can be found in Appendix A on Sheets C1.1 (Demo, Excavation, And Cleanup Plan), C2.1 (Rough Grading and TESC plan) and C3.1 and C3.2 (TESC Notes and Details). The SWPPS Site Plan, Pollution Prevention Report, and Spill Prevention and Cleanup Report have been developed , and BMPs have been selected based on Section 2.3.1.4 of the CRSWDM and the King County Stormwater Pollution Prevention Manual (KCSPPM). 5.1 Pollution and Spill Prevention Source Controls and BMPs The sources of pollution and spills will be identified by the Contractor in the spaces provided below, and the BMPs to be used for each source for prevention of both pollution and spills will be provided by the Contractor in the spaces provided below: Liquids shall not be stored onsite. Dry pesticides and fertilizers shall be covered with plastic sheeting or stored in a sealed container. Materials shall be stored on pallets or another raised method to prevent contact with stormwater runoff. Alternatively, the materials shall be contained in a manner such that if the container leaks or spills, the contents will not discharge, flow, or be washed into the storm drainage system, surface waters, or groundwater. Maintenance requirements are the same as liquid materials described above. Chemicals shall not be stored onsite. Soil, sand, and other erodible materials shall be covered with plastic sheeting per Detail 6 on Sheet C203. Perimeter controls shall be constructed as shown on the TESC plan to prevent eroded materials from leaving the project site. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 7 2180100.10 Fueling shall not occur onsite. If fueling does occur onsite, the Contractor shall develop a containment plan for spills and provide lighting and signage if fueling occurs at night in conformance with the KCSPPM. Maintenance and repair of vehicles shall not occur onsite. If maintenance or repair of vehicles does occur onsite, the Contractor shall develop a spill prevention plan in Conformance with the KCSPPM. Truck wheel washing, if required, shall occur at a wheel wash station as shown on City of Renton Standard Plan 215.00. All other vehicle washing shall occur in a controlled manner, such that runoff is collected and disposed of in a legal manner. Washing areas must be lined with an impervious membrane to prevent contamination of groundwater. Rinsing of hand tools is not applicable at this site. Contaminated soils shall be covered with plastic sheeting or contained to prevent stormwater from carrying pollutants away to surface or ground waters. Appropriate spill cleanup materials, such as brooms, dustpans, vacuum sweepers, etc., shall be stored and maintained near the storage area. Contractor shall refer to the NPDES administrative order for removal of contaminated soils. Area shall not be hosed down such that water drains to the storm drainage system, groundwater, surface water, or neighboring areas. During concrete and asphalt construction, NOT APPLICABLE TO THIS PHASE OF WORK. Water with elevated pH levels shall not be discharged from the site. Contractor shall monitor stormwater for pH prior to discharging from the site. Contractor shall implement a pH treatment plan if pH is not within the natural range 5.2 Responsible Personnel and Contact Information Jake Riley with PBS Engineering + Environmental shall be responsible for pollution and spill prevention and cleanup and can be contacted (206) 473-2542 or JAKE_RILEY@PBSENV.COM. Contractor shall fill out the attached Pollution Prevention Team Worksheet (see Appendix C). 5.3 Pollution and Spill Prevention Worksheets Pollution prevention, BMP implementation reports, material inventory worksheets, pollutant source identification worksheet, and spill/leak report may be found attached as Appendix C. 5.4 Disposal Methods Contractor shall dispose of contaminated soils and water in a legal manner. Options include the following: Disposal at a local landfill or at a recycling center, as allowed. 6.0 ESC Performance and Compliance Provisions 6.1 ESC Supervisor The Contractor shall appoint a Certified Erosion and Sediment Control Lead (CESCL) or Certified Professional in Erosion and Sediment Control (CPESC) (BMP D.4.1) for the project, and the appointee must be approved by the City. The duties of the CESCL or CPESC include: ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 8 2180100.10  Maintaining files onsite at all times, which include the Construction SWPPP and any associated permits and plans.  Directing BMP installation, inspection, maintenance, modification, and removal.  Keeping a log of all turbidity measurements taken onsite and making it available to City of Renton Community & Economic Development upon request.  Updating all project drawings and the Construction SWPPP with changes made.  Keeping daily logs and inspection reports.  Facilitating, participating in, and taking corrective actions resulting from inspections performed by outside agencies or the Owner. To aid in the implementation of the Construction SWPPP, the members of the SWPP Team include the following: the Contractor, the CESCL or CPESC, the City of Renton Inspector, and AHBL. The General Contractor will ensure all housekeeping and monitoring procedures are implemented, while the CESCL or CPESC will ensure the integrity of the structural BMPs. The City of Renton Inspector and CESCL will observe construction and erosion control practices and recommend revisions or additions to the Construction SWPPP and drawings. 6.2 Monitoring of Discharges The ESC supervisor shall have a turbidity meter onsite and shall use it to monitor surface and stormwater discharges from the project site whenever runoff occurs from onsite activities. A log of all turbidity measurements taken onsite shall be kept and made available to the City of Renton upon request. 6.3 ESC Performance ECS measures shall be installed and maintained to prevent, to the maximum extent pract icable, the transport of sediment from the project site to downstream drainage systems. Stormwater turbidity shall be monitored based on Section D.4.3 of the CRSWDM. 6.4 Flexible Compliance Any deviation to the Construction SWPPP will be documented and reported to the City for approval. 6.5 Roads and Utilities Compliance No alternative BMPs are used in road and utility compliance. 6.6 Alternative and Experimental Measures No alternative or experimental measures are to be used at this time. 7.0 ESC Implementation Requirements 7.1 Wet Season Requirements All of the following provisions for wet season construction are detailed in referenced sections: ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 9 2180100.10 1. The allowed time that a disturbed area may remain unworked without cover measures is reduced to two consecutive working days, rather than seven (D.3.2). 1. Stockpiles and steep cut and fill slopes are to be protected if unworked for more than 12 hours (D.3.2). 2. Cover materials sufficient to cover all disturbed areas shall be stockpiled onsite (D.3.2). 3. All areas that are to be unworked during the wet season shall be seeded within one week of the beginning of the wet season (D.3.2.5). 4. Mulch is required to protect all seeded areas (D.3.2.1). 5. Fifty linear feet of filter fabric fence (and the necessary stakes) per acre of disturbance must be stockpiled onsite (D.3.3.1). 6. Construction road and parking lot stabilization are required for all sites, unless the site is underlain by coarse-grained soil (D.3.4.2). 7. Sediment retention is required unless no offsite discharge is anticipated for the specifie d design flow (D.3.5). 8. Surface water controls are required, unless no offsite discharge is anticipated for the specified design flow (D.3.6). 9. Phasing and more conservative BMPs must be evaluated for construction activity near surface waters (D.5.3). 10. Any runoff generated by dewatering may be required to discharge to the sanitary sewer (with appropriate discharge authorization), portable sand filter systems, or holding tanks (D.2.1.7) 11. The frequency of maintenance review increases from monthly to weekly (D.5.4). 7.2 Critical Areas Restriction There is a Category III wetland with a 75-foot buffer located directly to the east of the site. No work will occur within the wetland as a part of the early clear and grade permit. 7.3 Maintenance Requirement All ESC measures shall be maintained and reviewed on a regular basis, as prescribed in the maintenance requirements for each BMP (see Appendix B). The ESC supervisor shall review the site at least twice a month during the dry season, weekly during the wet season, and within 24 hours of significant storms. The City may require that a written record of these reviews be kept onsite, with copies submitted to City of Renton Community & Economic Development within 48 hours. Documentation If DDES requires that a written record be maintained, a standard ESC Maintenance Report (D-95) may be used. A copy of all required maintenance reports shall be kept onsite throughout the duration of construction. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 10 2180100.10 The maintenance inspection report will be made after each inspection. Copies of th e report forms to be completed by the Construction SWPPP Coordinator are included in Appendix C of this Construction SWPPP. Completed forms will be provided to the City Inspector and will also be maintained onsite during the entire construction project. If construction activities or design modifications are made to the site plan that could impact stormwater, or if the Engineer of Record determines that the measures are not adequate to prevent erosion and the discharge of sediment from the site (based on turbidity measurements), this Construction SWPPP will be amended appropriately. The amended Construction SWPPP will have a description of the new activities that contribute to the increased pollutant loading and the planned source control activities. Review Timing During the wet season, weekly reviews shall be carried out every six to eight calendar days. During the dry season, monthly reviews shall be carried out within three days of the calendar day for the last inspection. Reviews shall also take place within 24 hours of significant storms. In general, a significant storm is one with more than 0.5 inch of rain in 24 hours or less. In order for the ESC facilities to function properly, they must be maintained and sediment removed on a regular basis. Inspection and sediment removal shall be performed on all ESC facilities, as described in the Inspection and Maintenance Report Forms included in Appendix C . 7.4 Construction Sequence 1. Hold the pre-construction meeting. 2. Post sign with name and phone number of ESC Supervisor (may be consolidated with the required notice of construction sign). 3. Secure the project site with security fencing. 4. Flag or fence clearing limits as required. Maintain Existing Silt Fencing. 5. Install inlet sediment protection along frontage. 6. Grade and install construction entrance. Maintain existing entrance. 7. Deliver and Configure stormwater storage tanks. Maintain system for discharge to sewer in accordance with King County Sewer Discharge Permit. 8. Maintain erosion control measures in accordance with City of Renton standards and manufacturer’s recommendations. 9. Construct temporary sediment traps. 10. Relocate erosion control measures or install new measures so that, as site conditions change, the erosion and sediment control is always in accordance with City of Renton erosion and sediment control standards. 11. Cover all areas that will be unworked for more than seven days during the dry season or two days during the wet season with straw, wood fiber mulch, compost, plastic sheeting, or equivalent. 12. Stabilize all areas within seven days of reaching final grade. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 11 2180100.10 13. Seed, sod, stabilize, or cover any areas to remain unworked for more than 30 days. 14. The wetland buffer shall be restored in accordance with the landscape plans. 15. Upon completion of the project, stabilize all disturbed areas and remove BMPs , if appropriate, and upon approval of the owner or engineer. 7.5 Final Stabilization Prior to obtaining final construction approval, the site shall be stabilized, the structural ESC measures such as silt fences removed, and drainage facilities cleaned. To obtain final construction approval, the following conditions must be met: 1. All disturbed areas of the site shall be vegetated or otherwise permanently stabilized. At a minimum, disturbed areas shall be seeded and mulched with a high likelihood that sufficient cover will develop shortly after final approval. Mulch without seeding is not adequate to allow final approval. 2. Structural measures, such as, but not limited to, filter fabric fences, pipe slope drains, construction entrances, and storm drain inlet protection, shall be removed from the site. Measures that will quickly decompose, such as brush barriers and organic mulches, may be left in place. The City of Renton inspector must approve an applicant’s proposal to remove fencing prior to the establishment of vegetation. 3. All permanent surface water facilities, including catch basins, manholes, pipes, ditches, channels, flow control facilities, and water quality facilities, shall be cleaned. Any offsite catch basin that required protection during construction shall also be cleaned 7.6 NPDES Requirements The CRSWDM is equivalent to the EPA required NPDES permit through the Stormwater Management Manual for Western Washington (Department of Ecology, 2012). The Department of Ecology stormwater permit application requires the filling of a Notice of Intent (NOI) at least 30 days prior to the start of construction 7.7 Forest Practice Permit Requirements The project does not clear more than 5,000 board feet of timber and does not require a Class IV Special Forest Practice permit from the Washington State Department of Natural Resources. 8.0 Construction Schedule Construction is scheduled to begin in fall 2018 and be completed by summer 2019. This analysis is based on data and records either supplied to or obtained by AHBL . These documents are referenced within the text of the analysis. The analysis has been prepared using procedures and practices within the standard accepted practices of the industry. We conclude that this project, as proposed, will not create any new problems within the existing downstream drainage system. This project will not noticeably aggravate any existing downstream problems due to either water quality or quantity. AHBL, Inc. ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 12 2180100.10 Matt Whittlesey, EIT Project Engineer MKW /lsk August 2018 Q:\2018\2180100\10_CIV\NON_CAD\REPORTS\SWPPP\20180802 Rpt (CSWPPP) _Early Start 2180100.10.docx ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendix A Exhibits A-1 .................... Vicinity Map A-2 .................... Existing Conditions Map C0.1 .................. Cover Sheet (Early Grading Permit) C0.2 .................. Existing Conditions (Topographic Survey) C0.3 .................. Test Pit and Excavation Map / Phasing Plan C1.1 .................. Demo, Excavation, and Clean-Up Plan C2.1 .................. Rough Grading and TESC Plan C3.1 .................. TESC Notes and Details C3.2 .................. TESC Notes an Details 2215 North 30th Street, Suite 300, Tacoma, WA 98403 253.383.2422 TEL 253.383.2572 FAX JOB NO: DATE: WALKER AUTO DEALERSHIP VICINITY MAP SCALE: 1" = 1/4 MILE (1320')EX-1 5/31/18 2180100.10 N SW 34TH ST 167 SITE 515 SW 27TH ST LIND AVE SWE VALLEY RDTALBOT RD SSE CARR RD SR 167SW 34TH ST EAST VALLEY ROADAHBL #103 REBAR AND CAP N 167257.03 E 1297746.82 ELEV: 19.67 AHBL #104 REBAR AND CAP N 166857.94 E 1297784.39 ELEV:20.22 75' WETLAND BUFFER TO BE RESTORED PARCEL #3023059067 PARCEL #3023059090 EAST VALLEY RV AND BOAT STORAGE PARCEL #3023059027 BRIGHT VIEW LANDSCAPING PARCEL #1253600010 YOUNKER NISSAN PARCEL #1253800030 HARTENG GLASS CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 N GRAPHIC SCALE 0 50 100 1" = 50 FEET 25 PARCEL #3023059067 PER KING COUNTY ASSESSOR THAT PORTION OF THE SOUTH 1/2 OF THE NORTHWEST 1/4 OF THE SOUTHEAST 1/4 OF SECTION 30, TOWNSHIP 23 NORTH, RANGE 5 EAST OF THE WILLAMETTE MERIDIAN LYING WESTERLY OF STATE HIGHWAY #5. EXCEPT THE SOUTH 194 FEET THEREOF AND EXCEPT THE WEST 30 FEET THEREOF. LEGAL DESCRIPTION NAVD 1988 VERTICAL DATUM ON ORTHOMETRICALLY CORRECTED GPS OBSERVATIONS USING WSRN AND GEOID 2012A. VERIFIED CITY OF RENTON 230 (CASE MONUMENT AT S 23RD ST AND WILLIAMS AVE CUL DE SAC) ELEV: 230.75 VERTICAL DATUM NAD 1983 WASHINGTON STATE PLANE NORTH PROJECTION, BASED ON GPS OBSERVATIONS USING WSRN AND GEOID 2012A. UNITS OF MEASUREMENT ARE US SURVEY FEET. VERIFIED CITY OF RENTON 230 (CASE MONUMENT AT S 23RD ST AND WILLIAMS AVE CUL DE SAC) BASIS OF BEARING P T W W FOUND MONUMENT AS NOTED SET REBAR AND CAP FOUND PROPERTY CORNER MONITORING WELL BOLLARD MAIL BOX SIGN AS NOTED TEST PIT SANITARY SEWER CLEANOUT SANITARY SEWER MANHOLE STORM CATCH BASIN STORM MANHOLE CABLE RISER GAS METER GAS VALVE TRAFFIC CABINET POWER TRANSFORMER GUY ANCHOR UTILITY POWER POLE JUNCTION BOX POWER MANHOLE POWER METER LUMINAIRE COMMUNICATIONS MANHOLE TELEPHONE RISER TELEPHONE VAULT BLOW OFF VALVE FIRE DEPARTMENT CONNECTION FIRE HYDRANT HOSE BIB IRRIGATION CONTROL VALVE WATER METER WATER MANHOLE POST INDICATOR VALVE WATER VALVE WATER VAULT F-FIR, P-PINE U-UNKNOWN POWER VAULT HB ROOF DRAIN STORM LINE SEWER LINE WATER LINE GAS LINE ELECTRICAL LINE COMMUNICATION LINE OVERHEAD UTILITIES SPLIT RAIL FENCE LEGEND ASPHALT CONCRETE SILT FENCE EXISTING PROPOSED D&C INVESTMENT, LLC. P.O. BOX 1657 TACOMA, WA 98401 CELL: (206) 391-0311 CONTACT: DALE WALKER OWNER CIVIL ENGINEER SURVEYOR AHBL 2215 NORTH 30TH STREET, SUITE 300 TACOMA, WA 98403 PH. (253) 383-2422 FAX (253) 383-2572 CONTACT: MATT WEBER, PE AHBL 2215 NORTH 30TH STREET, SUITE 300 TACOMA, WA 98403 PH. (253) 383-2422 FAX (253) 383-2572 CONTACT: DAVE FOLLANSBEE, PLS GEOTECHNICAL MIGIZI GROUP, INC. P.O. BOX 44840 TACOMA, WA 98448 PH: (253) 537-9400 CONTACT: JIM BRIGHAM, PE IF WORKERS ENTER ANY TRENCH OR OTHER EXCAVATION FOUR OR MORE FEET IN DEPTH THAT DOES NOT MEET THE OPEN PIT REQUIREMENTS OF WSDOT SECTION 2-09.3(3)B, IT SHALL BE SHORED AND CRIBBED. THE CONTRACTOR ALONE SHALL BE RESPONSIBLE FOR WORKER SAFETY AND AHBL ASSUMES NO RESPONSIBILITY. ALL TRENCH SAFETY SYSTEMS SHALL MEET THE REQUIREMENTS OF THE WASHINGTON INDUSTRIAL SAFETY AND HEALTH ACT, CHAPTER 49.17 RCW. THE LOCATIONS OF EXISTING UNDERGROUND UTILITIES ARE APPROXIMATE ONLY AND HAVE NOT BEEN INDEPENDENTLY VERIFIED BY THE OWNER OR ITS REPRESENTATIVE. THE CONTRACTOR SHALL DETERMINE THE EXACT LOCATION OF ALL EXISTING UTILITIES BEFORE COMMENCING WORK AND AGREES TO BE FULLY RESPONSIBLE FOR ANY AND ALL DAMAGES THAT HAPPEN DUE TO THE CONTRACTOR'S FAILURE TO LOCATE EXACTLY AND PRESERVE ANY AND ALL UNDERGROUND UTILITIES. AHBL ASSUMES NO LIABILITY FOR THE LOCATION OF UNDERGROUND UTILITIES. FILL MATERIAL SHALL NOT CONTAIN PETROLEUM PRODUCTS, OR SUBSTANCES WHICH ARE HAZARDOUS, DANGEROUS, TOXIC, OR WHICH OTHERWISE VIOLATE ANY STATE, FEDERAL, OR LOCAL LAW, ORDINANCE, CODE, REGULATION, RULE, ORDER, OR STANDARD. UTILITY NOTE FILL SPECIFICATION TRENCH NOTE 3400 EAST VALLEY ROAD RENTON, WA 98057 SITE ADDRESS 3023059067 PARCEL # SHEET INDEX SHEET NO.SHEET TITLE C0.1 COVER SHEET C0.2 EXISTING CONDITIONS C1.1 TESC AND DEMOLITION PLAN C2.1 ROUGH GRADING PLAN C2.2 SITE SECTIONS C2.3 SITE SECTIONS C3.1 TESC NOTES AND DETAILS C3.2 TESC NOTES AND DETAILS COVER SHEET C0.1 1 1. SITE WILL BE BROKEN INTO APPROXIMATELY 4 WORK SECTIONS. CLEAN SURFACE GRAVEL WILL BE SCRAPED AND STOCKPILED. 2. EXCAVATE CONTAMINATED MATERIALS PER STEMEN ENVIRONMENTAL'S RECOMMENDATIONS. EXCAVATED MATERIAL SHALL BE STOCKPILED (UNDER COVER) DURING CONTAMINATED SOIL SAMPLING AND TESTING. 3. EXCAVATE AND GRADE ACTIVE WORK SECTION TO ACCOMMODATE 2.0' STRUCTURAL FILL SECTION (EXCEPT BUFFER). REFER TO SITE CROSS SECTIONS. 4. IMPORT AND PLACE STRUCTURAL FILL PER GRADING PLAN ON SHEET C2.1 AND PER GEOTECHNICAL ENGINEER'S RECOMMENDATION. FINAL GRADES SHALL CORRESPOND TO SUBGRADE FOR FUTURE BUILDING AND PAVEMENT SECTIONS. 5. GRADING SHALL BE OBSERVED BY THE GEOTECHNICAL ENGINEER. COORDINATE COMPACTION TESTING WITH THE GEOTECHNICAL ENGINEER. EARTHWORK SEQUENCE VICINITY MAP SCALE: 1"=1/4 MILE N Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-COVR.dwgWALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS SITE SW 34TH ST SW 27TH ST LIND AVE SW167 515E VALLEY RDTALBOT RD SSE CARR RD FUTURE CAR DEALERSHIP 1 * REFER TO LANDSCAPE PLANS FOR BUFFER RESTORATION SPLIT RAIL FENCE WSDOT SERVICE GATE WSDOT SERVICE GATE 6' CHAINLINK SECURITY FENCE WITH 3-STRAND BARBWIRE CHAINLINK FENCE BUILDING OUTLINE PAVEMENT OUTLINE T EAST VALLEY ROADS.R. 167SW 34TH ST CURVE TABLE CURVE #LENGTH RADIUS DELTA CHORD DIRECTION CHORD LENGTH VERTICAL DATUM BASIS OF BEARING N GRAPHIC SCALE 0 30 60 FEET 1" = 30 FEET 15 T LEGEND CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 EXISTING CONDITIONS C0.2 2Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-EXST.dwg2 T EAST VALLEY ROADS.R. 167SW 34TH ST CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 B-1 B-2 B-3 B-4 DEPTH = 4FT B-5 B-6 DEPTH = 3FT B-7 B-8 B-9 B-10 DEPTH = 3FT B-11 DEPTH = 3FT B-12 B-13 B-14 B-15 DEPTH = 4FT B-16 B-17 B-18 B-19 B-20 DEPTH = 5FT R-1 R-2 R-3 R-4 R-5 R-6 S-3 S-1 S-2 S-11 S-9 S-30 S-7 DEPTH = 2FT S-12 S-13 S-14 S-23 S-15 S-16 S-28 S-29 S-20 DEPTH = 3FT S-6 S-17 S-18 S-21 S-19 S-26 S-25 S-22 DEPTH = 3FT S-24 DEPTH = 3FT S-8 S-27 S-10 DEPTH = 10FT APPROXIMATE LOCATION OF TEST PITS APPROXIMATE PROPERTY BOUNDARY APPROXIMATE BUILDING OUTLINE APPROXIMATE FENCE LOCATION APPROXIMATE BORING LOCATION APPROXIMATE DEPTH OF "HOT SPOT" IDENTIFIED SOIL CONTAMINATION PHASE LINE WORK AREA PHASE 1 WORK AREA PHASE 2 WORK AREA PHASE 3 WORK AREA PHASE 4 WORK AREA PHASE 5 1.SAMPLING LOCATIONS LISTED ON THIS SHEET PER KANE ENVIRONMENTAL PROJECT NO. 51213 AS ANNOTATED BY STEMENS ENVIRONMENTAL. 2.PHASE LINES ARE APPROXIMATE AND SUBJECT TO CHANGE BASED ON FIELD CONDITIONS. DEPTH = LEGEND R / B - # S - # GENERAL NOTES GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 NPARKING LOT AND BUILDING DEMOLITION IS LAST PHASE OF CLEANUP. BUILDING WILL BE USED AS CONSTRUCTION OFFICE. C0.3 3 TEST PIT AND EXCAVATION MAP PHASING PLAN 3 T SR 167SW 34TH ST EAST VALLEY ROAD5 5 1 2 (TYP.) 3 (TYP.) 4 (TYP.) 6 STCB 502 RIM=19.51 4" IP NE IE=16.60 12" CONC SW IE=13.76 NE PIPE CAPPED SF CL CE TEMPORARY STORM PIPE 40 LF 12" CPEP @ 1.0% 12" CPEP NE=13.71 (CORE & GROUT NEW PIPE) 6 75.00' FLAG THE WETLAND BUFFER WETLAND BOUNDARY PROTECT MONITORING WELL (TYP.) DEMO 6" CPP'S ID RIDGE LINE STRIPPED GRADE CONTOUREXISTING GRADE CONTOUR -1.79-1.79 0.230.23 0.320.32 -0.16-0.16 -0.98-0.98 -1.59-1.59 1.411.41 1.111.11 0.960.96 0.320.32 1.271.27 1.861.86 1.501.50 2.422.42 0.510.51 -0.74-0.74 -0.29-0.29 -1.40-1.40 -2.31-2.31 -2.67-2.67 -2.17-2.17 -1.66-1.66 -2.74-2.74 -2.94-2.94 -1.79-1.79 1.051.05 1.331.33 0.820.82 0.560.56 1.821.82 1.871.87 1.641.64 1.781.78 0.950.95 0.100.10 -0.71-0.71 -1.60-1.60 -2.21-2.21 -2.22-2.22 -2.07-2.07 -1.64-1.64 -1.77-1.77 -2.48-2.48 -1.82-1.82 0.960.96 1.531.53 0.760.76 1.041.04 1.221.22 1.231.23 1.511.51 1.621.62 1.431.43 1.091.09 -1.39-1.39 -1.87-1.87 -2.66-2.66 -2.80-2.80 -2.69-2.69 -2.47-2.47 -2.19-2.19 -2.11-2.11 -1.90-1.90 0.400.40 1.241.24 1.081.08 0.750.75 0.890.89 1.471.47 1.501.50 1.341.34 0.650.65 -0.19-0.19 -2.46-2.46 -2.11-2.11 -3.01-3.01 -3.24-3.24 -2.94-2.94 -2.94-2.94 -2.77-2.77 -2.84-2.84 -2.00-2.00 -0.07-0.07 1.081.08 0.560.56 1.071.07 0.980.98 1.781.78 1.231.23 0.630.63 -0.47-0.47 -1.79-1.79 -2.06-2.06 -2.76-2.76 -3.14-3.14 -3.26-3.26 -3.43-3.43 -3.37-3.37 -3.40-3.40 -2.97-2.97 -1.89-1.89 0.410.41 1.171.17 0.850.85 1.021.02 1.021.02 2.062.06 1.511.51 0.590.59 -0.52-0.52 -1.63-1.63 -2.64-2.64 -2.86-2.86 -3.18-3.18 -3.37-3.37 -3.67-3.67 -3.56-3.56 -3.29-3.29 -2.81-2.81 -1.95-1.95 -0.22-0.22 0.800.80 0.890.89 1.021.02 1.671.67 2.152.15 1.651.65 0.600.60 -0.74-0.74 -1.84-1.84 -2.64-2.64 -2.86-2.86 -3.16-3.16 -3.48-3.48 -3.56-3.56 -3.12-3.12 -2.72-2.72 -2.13-2.13 -2.35-2.35 -1.12-1.12 -0.41-0.41 0.050.05 1.031.03 1.961.96 2.172.17 1.621.62 0.450.45 -1.07-1.07 -1.60-1.60 -2.05-2.05 -2.58-2.58 -3.04-3.04 -3.07-3.07 -3.20-3.20 -2.72-2.72 -2.19-2.19 -1.96-1.96 -2.71-2.71 -1.29-1.29 -0.65-0.65 -0.09-0.09 0.920.92 1.651.65 2.002.00 1.411.41 0.460.46 -1.17-1.17 -1.42-1.42 -1.86-1.86 -2.43-2.43 -3.07-3.07 -3.25-3.25 -3.34-3.34 -2.87-2.87 -2.25-2.25 -1.51-1.51 -2.71-2.71 -1.39-1.39 -0.50-0.50 0.090.09 0.940.94 1.501.50 1.641.64 1.101.10 0.250.25 -1.32-1.32 -1.57-1.57 -1.95-1.95 -2.35-2.35 -3.00-3.00 -3.03-3.03 -3.07-3.07 -2.68-2.68 -2.28-2.28 -1.89-1.89 -2.61-2.61 -1.91-1.91 -0.97-0.97 -0.37-0.37 0.660.66 1.041.04 1.021.02 0.910.91 -0.31-0.31 -1.67-1.67 -2.24-2.24 -2.41-2.41 -2.49-2.49 -2.77-2.77 -2.85-2.85 -3.00-3.00 -2.65-2.65 -2.21-2.21 -2.27-2.27 -2.08-2.08 -1.87-1.87 -1.26-1.26 -0.97-0.97 0.170.17 0.400.40 0.140.14 0.230.23 -1.15-1.15 -1.90-1.90 -2.23-2.23 -2.27-2.27 -2.45-2.45 -2.53-2.53 -2.83-2.83 -2.62-2.62 -2.28-2.28 -1.65-1.65 -0.39-0.39 -1.91-1.91 -1.45-1.45 -0.63-0.63 -0.43-0.43 -0.21-0.21 -0.23-0.23 -0.57-0.57 -0.75-0.75 -1.44-1.44 -2.08-2.08 -2.26-2.26 -2.22-2.22 -2.36-2.36 -2.65-2.65 -2.71-2.71 -2.65-2.65 -2.39-2.39 -1.87-1.87 -1.48-1.48 -1.67-1.67 -1.15-1.15 -0.54-0.54 -0.31-0.31 -0.22-0.22 -0.62-0.62 -1.01-1.01 -1.52-1.52 -1.71-1.71 -2.21-2.21 -2.23-2.23 -1.93-1.93 -2.02-2.02 -1.97-1.97 -2.07-2.07 -2.10-2.10 -2.07-2.07 -2.05-2.05 -0.72-0.72 -1.98-1.98 -1.68-1.68 -1.20-1.20 -1.03-1.03 -0.93-0.93 -1.21-1.21 -1.65-1.65 -1.70-1.70 -1.88-1.88 -1.97-1.97 -1.95-1.95 -1.81-1.81 -1.62-1.62 -1.46-1.46 -1.48-1.48 -1.53-1.53 -1.47-1.47 -1.33-1.33 -0.38-0.38 -2.16-2.16 -1.79-1.79 -1.62-1.62 -1.56-1.56 -1.56-1.56 -1.40-1.40 -1.46-1.46 -1.52-1.52 -1.77-1.77 -1.93-1.93 -1.88-1.88 -1.71-1.71 -1.49-1.49 -1.38-1.38 -1.21-1.21 -0.89-0.89 -0.64-0.64 -0.53-0.53 -0.95-0.95 -1.67-1.67 -1.60-1.60 -1.62-1.62 -1.61-1.61 -1.57-1.57 -1.51-1.51 -1.70-1.70 -1.76-1.76 -1.58-1.58 -1.41-1.41 -1.40-1.40 -1.26-1.26 -1.08-1.08 -0.83-0.83 -0.67-0.67 -0.36-0.36 0.390.39 -1.40-1.40 -1.32-1.32 -1.26-1.26 -1.08-1.08 -0.90-0.90 -0.74-0.74 -0.62-0.62 -0.38-0.38 0.280.28 -0.27-0.27 WETLAND BUFFER TO BE RESTORED. REFER TO LANDSCAPE PLAN. 0.590.59 LOCATE EXISTING SEWER STUB. DISCHARGE TO SEWER UNDER APPROVED DISCHARGE PERMIT AND PROVIDE SURFACE CLEANOUT FOR DISCHARGE. TEMPORARY STORMWATER TANKS FOR TREATMENT PUMP SUCTION MAINTAIN CONSTRUCTION ENTERANCE (TYP) 5 MINIMUM EXCAVATION DEPTH TO SUBGRADE (TYP.) MH 2987 CE CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 N GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 TESC AND DEMO LEGEND INLET PROTECTION SILT FENCE CLEARING LIMITS DEMO EXISTING UTILITY CONSTRUCTION ENTRANCE REMOVE EXISTING ASPHALT REMOVE EXISTING CONCRETE REMOVE EXISTING BUILDING REMOVE EXISTING FENCE EXISTING GRADE CONTOUR CL SF IP DEMO, EXCAVATION, AND CLEAN-UP PLAN C1.1 4 COVER ALL CONTAMINATED SOIL STOCKPILES STRAW COVER ALL DISTURBED AREAS. KEY NOTES REMOVE EXISTING BUILDING (REFER TO SEPARATE DEMOLITION PERMIT) REMOVE EXISTING CURB REMOVE EXISTING WHEEL STOPS REMOVE EXISTING FENCE REMOVE STORM PIPE CAP EXISTING UTILITY AND ABANDON PER CITY OF RENTON AND PURVEYOR STANDARDS 1 2 3 4 5 6 CE WETLAND BUFFER NOTE RESTORATION OF THE ONSITE WETLAND BUFFER SHALL CONSIST OF REMOVAL OF EXISTING GRAVEL AND PLACEMENT OF 3" BARK MULCH OVER 18" OF BIO-RETENTION SOIL MIX. SOIL MIX SHALL CONFORM TO CITY OF RENTON SWDM SECTION 11-C.2 Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-TESC.dwgELEV EXCAVATION/STORMWATER NOTES 1.DURING THE EXCAVATION AND CLEANUP PHASE, DISCHARGE STORMWATER FROM PUMP TO (2) TEMPORARY STORMWATER TANKS. 1.1.TANKS SHALL BE BAKER TANK OR APPROVED EQUAL. 1.2.STORMWATER FROM THE TANKS MUST BE DISCHARGED OFF-SITE OR AS APPROVED IN THE KING COUNTY DISCHARGE PERMIT. 1.3.ANY PERMIT OR OTHER FEES ASSOCIATED WITH DISCHARGES ARE THE RESPONSIBILITY OF THE CONTRACTOR. 1.4.LOCATIONS SHOWN ON PLAN ARE SUGGESTIONS ONLY. THE CONTRACTOR WILL DECIDE THE LOCATIONS OF THE TANKS. 2.SCRAPE CLEAN SURFACE GRAVELS FROM WORK AREA FOR REUSE ONSITE. 3.EXCAVATE CONTAMINATED SOILS AS REQUIRED TO MEET CLEANUP LEVELS. HAUL ALL CONTAMINATED SOIL TO AN AUTHORIZED DISPOSAL SITE. 4.PROTECT RECLAIMED AREAS FROM RE-CONTAMINATION. FORCE MAIN LINE IS DIAGRAMATIC. SITE WILL BE EXCAVATED IN SECTIONS. SUCTION WILL BE MAINTAINED AT ACTIVE EXCAVATIONS AS NEEDED FOR DEWATERING. IP (TYP.) CONTRACTOR TO PROTECT EXISTING BUILDING AND STORM DRAIN SYSTEM. EXCAVATION SHALL NOT ENTER ZONE OF INFLUENCE OF BUILDING FOUNDATION. 4 T 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 A C2.2 B C2.2 C C2.2 0+001+002+003+004+005+005+250+001+002+003+004+005+005+250+001+002+003+004+005+005+25D C2.3 E C2.3 F C2.3 FUTURE BUILDING PAD SUBGRADE ELEV: 21.25 SR 167SW 34TH ST EAST VALLEY ROADFS: 18.07FS: 17.67FS: 13.71FS: 13.71FS: 18.03FS: 20.55FS: 20.48FS: 20.51FS: 20.55FS: 20.09FS: 19.34FS: 20.60FS: 20.56FS: 20.48FS: 20.39FS: 20.30FS: 20.17FS: 18.75FS: 18.66FS: 18.14FS: 17.52FS: 13.71FS: 13.71FS: 18.19FS: 20.57FS: 20.42FS: 20.08FS: 20.39FS: 20.21FS: 19.94FS: 20.51FS: 20.59FS: 20.54FS: 20.48FS: 20.43FS: 20.24FS: 19.67FS: 19.68FS: 18.69FS: 17.36FS: 13.71FS: 13.71FS: 18.34FS: 20.57FS: 20.55FS: 20.55FS: 20.55FS: 20.55FS: 20.64FS: 20.68FS: 20.69FS: 20.60FS: 20.56FS: 20.57FS: 20.54FS: 20.58FS: 20.57FS: 19.16FS: 17.21FS: 13.71FS: 13.71FS: 18.50FS: 20.47FS: 21.10FS: 20.94FS: 20.89FS: 20.88FS: 20.92FS: 20.57FS: 20.37FS: 20.22FS: 20.19FS: 20.14FS: 20.13FS: 19.57FS: 17.06FS: 13.71FS: 13.71FS: 18.65FS: 20.61FS: 21.17FS: 20.50FS: 20.32FS: 20.12FS: 19.90FS: 19.69FS: 19.82FS: 19.57FS: 16.91FS: 13.71FS: 13.71FS: 18.80FS: 20.74FS: 21.19FS: 20.28FS: 20.08FS: 19.87FS: 19.85FS: 19.91FS: 19.75FS: 16.75FS: 13.71FS: 13.71FS: 18.95FS: 20.99FS: 21.23FS: 20.26FS: 20.27FS: 20.29FS: 20.30FS: 20.31FS: 20.09FS: 16.60FS: 13.71FS: 13.71FS: 19.11FS: 21.25FS: 21.25FS: 20.48FS: 20.46FS: 20.45FS: 20.43FS: 20.42FS: 20.54FS: 16.45FS: 13.71FS: 13.71FS: 19.26FS: 21.25FS: 21.25FS: 20.29FS: 20.09FS: 19.96FS: 19.95FS: 19.95FS: 20.56FS: 20.06FS: 19.89FS: 19.78FS: 20.38FS: 21.25FS: 21.25FS: 20.33FS: 20.14FS: 19.93FS: 19.72FS: 19.83FS: 20.41FS: 19.99FS: 19.75FS: 19.65FS: 20.37FS: 20.39FS: 20.27FS: 20.22FS: 20.18FS: 20.14FS: 19.95FS: 20.16FS: 19.75FS: 19.44FS: 20.51FS: 20.45FS: 20.49FS: 20.52FS: 20.56FS: 20.58FS: 19.92FS: 20.42FS: 20.27FS: 20.31FS: 20.70FS: 20.59FS: 20.37FS: 20.17FS: 20.20FS: 20.22FS: 20.00FS: 21.05FS: 21.04FS: 21.06FS: 21.17FS: 21.19FS: 20.75FS: 20.55FS: 20.28FS: 20.01FS: 20.17FS: 19.91FS: 20.80FS: 20.80FS: 20.83FS: 20.95FS: 21.12FS: 21.12FS: 21.09FS: 21.10FS: 21.11FS: 21.11FS: 21.10FS: 21.08FS: 21.05FS: 20.96FS: 20.75FS: 20.58FS: 20.41FS: 20.29FS: 19.44FS: 20.53FS: 20.54FS: 20.58FS: 20.68FS: 20.78FS: 20.79FS: 20.80FS: 20.81FS: 20.83FS: 20.85FS: 20.87FS: 20.89FS: 20.90FS: 20.92FS: 20.94FS: 20.96FS: 20.92FS: 20.79FS: 20.44FS: 20.28FS: 20.31FS: 20.37FS: 20.42FS: 20.46FS: 20.48FS: 20.50FS: 20.53FS: 20.56FS: 20.58FS: 20.61FS: 20.63FS: 20.66FS: 20.68FS: 20.71FS: 20.73FS: 20.79FS: 19.25FS: 20.19FS: 20.27FS: 20.30FS: 20.33FS: 20.36FS: 20.39FS: 20.42FS: 20.45FS: 20.47FS: 20.62FS: 19.25FS: 19.67FS: 20.46FUTURE BUILDING OUTLINE FUTURE EDGE OF PAVING (TYP.)FS: 18.96FS: 18.48FS: 21.06FS: 20.86FS: 20.74FS: 20.73FS: 20.82FS: 20.54FS: 19.58FS: 18.37FS: 20.65FS: 20.51FS: 20.39FS: 20.39FS: 20.58FS: 20.71FS: 20.54FS: 20.46FS: 20.54FS: 20.47FS: 20.38FS: 20.23FS: 20.15FS: 20.04FS: 20.10FS: 18.12FS: 18.94FS: 20.10FS: 19.80FS: 20.11FS: 20.22FS: 20.40FS: 20.33FS: 20.36FS: 20.03FS: 19.98FS: 19.95FS: 19.81FS: 19.61FS: 19.53FS: 19.37FS: 19.39FS: 19.37FS: 18.80FS: 19.43FS: 19.57FS: 19.16FS: 19.49FS: 19.20FS: 19.20FS: 18.95FS: 18.96FS: 19.01FS: 18.97FS: 18.40FS: 18.12FS: 17.62STRIPPED GRADE CONTOUR FINAL SUBGRADE CONTOUR TEMPORARY STORM PIPE 40 LF 12" CPEP @ 1.0% SEDIMENT TRAP RISER 12" CPEP SW=14.0 TEMPORARY SEDIMENT TRAP MIN. SURFACE AREA:1800 SF BERM ELEV: 19.0 WS ELEV: 18.0 BOTTOM ELEV: 14.5 BERM ELEV: 19.0 BOTTOM ELEV: 14.5 RR RR SPILLWAY ELEV: 18.0 SF MAINTAIN CONSTRUCTION ENTERANCE (TYP) HIGH POINTFS: 21.03FS: 21.05FS: 21.09FS: 20.47FS: 21.10FS: 20.46FS: 21.11FS: 20.50FS: 21.11FS: 20.47FS: 21.11FS: 20.50FS: 21.16FS: 20.56FS: 21.12FS: 21.10FS: 21.18FS: 20.65FS: 21.02FS: 20.90TEMPORARY SEDIMENT TRAP MIN. SURFACE AREA:1900 SF BERM ELEV: 16.5 WS ELEV: 15.5 BOTTOM ELEV: 12.0 BERM ELEV: 16.5 BOTTOM ELEV: 12.0 REFER TO LANDSCAPE PLANS FOR BUFFER RESTORATION2020202121 21 20 21212 1 20201920 2019CONTRACTOR TO PROTECT EXISTING BUILDING AND STORM DRAIN SYSTEM. EXCAVATIONS SHALL NOT ENTER ZONE OF INFLUENCE OF BUILDING FOUNDATION. OUTER SILT FENCE CAN BE REMOVED WHEN BUFFER IS STABILIZED N GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 EARTHWORK VOLUMES ANTICIPATED CONTAMINATED SOIL REMOVAL (ASSUMING 1' DEPTH OF REMOVAL): 9,100 CY CUT:7,000 CY FILL:19,800 CY NET:12,800 (IMPORT) NOTE: VOLUMES ARE STRIPPED GRADE TO FINAL SUBGRADE. THE ABOVE QUANTITIES ARE ESTIMATES ONLY INTENDED FOR THE PERMITTING PROCESS. DO NOT USE FOR BID PURPOSES. THE QUANTITIES DO NOT HAVE STRIPPING, COMPACTION, OR CUT OR FILL ADJUSTMENT FACTORS APPLIED TO THEM. CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 ROUGH GRADING AND TESC PLAN C2.1 5 STABILIZE ALL DISTURBED AREAS WITH ROCK SURFACING AND STRAW Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-GRAD.dwgEATHWORK LEGEND FS = FINAL SUBGRADE FINAL SUBGRADE CONTOUR STRIPPED SURFACE CONTOUR NOTE: FINAL SUBGRADE SHALL BE UNDERLAIN BY 2.0' OF STRUCTURAL FILL IN BUILDING AND PAVED AREAS PER GEOTECHNICAL ENGINEER'S RECOMMENDATION. ELEV ELEV 75.00' WETLAND BUFFER TESC LEGEND RIPRAP ROCKERY 6"-8" QUARRY SPALLS GRAVEL CHECK DAM INTERCEPTOR DITCH @ 0.3% MINIMUM INLET PROTECTION SILT FENCE CLEARING LIMITS SEDIMENT TRAP RISER CONSTRUCTION ENTRANCE CL SF IP ID CD RR CE CE CE SF ID ID ID SF SF SF SF 5 CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 TESC NOTES AND DETAILS C3.1 8Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-TESC.dwg1.BEFORE ANY CONSTRUCTION OR DEVELOPMENT ACTIVITY OCCURS, A PRE-CONSTRUCTION MEETING SHALL BE HELD AMONG THE CITY OF RENTON, HEREBY REFERRED TO AS THE CITY, THE APPLICANT, AND THE APPLICANT’S CONTRACTOR. 2.THE APPLICANT IS RESPONSIBLE FOR OBTAINING THE WASHINGTON STATE DEPARTMENT OF ECOLOGY (ECOLOGY) CONSTRUCTION STORMWATER GENERAL PERMIT, IF IT IS REQUIRED FOR THE PROJECT. THE APPLICANT SHALL PROVIDE THE CITY COPIES OF ALL MONITORING REPORTS PROVIDED TO ECOLOGY ASSOCIATED WITH THE CONSTRUCTION STORMWATER GENERAL PERMIT. 3.THE ESC PLAN SET SHALL INCLUDE AN ESC CONSTRUCTION SEQUENCE DETAILING THE ORDERED STEPS THAT SHALL BE FOLLOWED FROM THE PRE-CONSTRUCTION MEETING TO POST-PROJECT CLEANUP IN ORDER TO FULFILL PROJECT ESC REQUIREMENTS. 4.THE BOUNDARIES OF THE CLEARING LIMITS, SENSITIVE AREAS AND THEIR BUFFERS, AND AREAS OF VEGETATION PRESERVATION AND TREE RETENTION, AS PRESCRIBED ON THE PLAN(S), SHALL BE CLEARLY FLAGGED BY SURVEY TAPE OR FENCING AND PROTECTED IN THE FIELD IN ACCORDANCE WITH APPENDIX D OF THE CITY OF RENTON SURFACE WATER DESIGN MANUAL (RSWDM) PRIOR TO CONSTRUCTION. DURING THE CONSTRUCTION PERIOD, NO DISTURBANCE BEYOND THE CLEARING LIMITS SHALL BE PERMITTED. THE CLEARING LIMITS SHALL BE MAINTAINED BY THE APPLICANT/ESC SUPERVISOR FOR THE DURATION OF CONSTRUCTION. 5.STABILIZED CONSTRUCTION ENTRANCES SHALL BE INSTALLED AT THE BEGINNING OF CONSTRUCTION AND MAINTAINED FOR THE DURATION OF THE PROJECT. ADDITIONAL MEASURES, SUCH AS CONSTRUCTED WHEEL WASH SYSTEMS OR WASH PADS, MAY BE REQUIRED TO ENSURE THAT ALL PAVED AREAS ARE KEPT CLEAN AND TRACK-OUT TO ROAD RIGHT OF WAY DOES NOT OCCUR FOR THE DURATION OF THE PROJECT. IF SEDIMENT IS TRACKED OFFSITE, PUBLIC ROADS SHALL BE CLEANED THOROUGHLY AT THE END OF EACH DAY, OR MORE FREQUENTLY DURING WET WEATHER, AS NECESSARY TO PREVENT SEDIMENT FROM ENTERING WATERS OF THE STATE. 6.WASHOUT FROM CONCRETE TRUCKS SHALL BE PERFORMED OFF-SITE OR IN DESIGNATED CONCRETE WASHOUT AREAS ONLY. DO NOT WASH OUT CONCRETE TRUCKS ONTO THE GROUND, OR TO STORM DRAINS OR OPEN DITCHES. ON-SITE DUMPING OF EXCESS CONCRETE SHALL ONLY OCCUR IN DESIGNATED CONCRETE WASHOUT AREAS. 7.ALL REQUIRED ESC BMPS SHALL BE CONSTRUCTED AND IN OPERATION PRIOR TO LAND CLEARING AND/OR CONSTRUCTION TO PREVENT TRANSPORTATION OF SEDIMENT TO SURFACE WATER, DRAINAGE SYSTEMS AND ADJACENT PROPERTIES. ALL ESC BMPS SHALL BE MAINTAINED IN A SATISFACTORY CONDITION UNTIL SUCH TIME THAT CLEARING AND/OR CONSTRUCTION IS COMPLETE AND POTENTIAL FOR ON-SITE EROSION HAS PASSED. ALL ESC BMPS SHALL BE REMOVED AFTER CONSTRUCTION IS COMPLETED AND THE SITE HAS BEEN STABILIZED TO ENSURE POTENTIAL FOR ON-SITE EROSION DOES NOT EXIST. THE IMPLEMENTATION, MAINTENANCE, REPLACEMENT, ENHANCEMENT, AND REMOVAL OF ESC BMPS SHALL BE THE RESPONSIBILITY OF THE APPLICANT. 8.ANY HAZARDOUS MATERIALS OR LIQUID PRODUCTS THAT HAVE THE POTENTIAL TO POLLUTE RUNOFF SHALL BE DISPOSED OF PROPERLY. 9.THE ESC BMPS DEPICTED ON THIS DRAWING ARE INTENDED TO BE MINIMUM REQUIREMENTS TO MEET ANTICIPATED SITE CONDITIONS. AS CONSTRUCTION PROGRESSES AND UNEXPECTED OR SEASONAL CONDITIONS DICTATE, THE APPLICANT SHALL ANTICIPATE THAT MORE ESC BMPS WILL BE NECESSARY TO ENSURE COMPLETE SILTATION CONTROL ON THE PROPOSED SITE. DURING THE COURSE OF CONSTRUCTION, IT SHALL BE THE OBLIGATION AND RESPONSIBILITY OF THE APPLICANT TO ADDRESS ANY NEW CONDITIONS THAT MAY BE CREATED BY THE ACTIVITIES AND TO PROVIDE ADDITIONAL ESC BMPS, OVER AND ABOVE MINIMUM REQUIREMENTS, AS MAY BE NEEDED, TO PROTECT ADJACENT PROPERTIES AND WATER QUALITY OF THE RECEIVING DRAINAGE SYSTEM. 10.APPROVAL OF THIS PLAN IS FOR ESC ONLY. IT DOES NOT CONSTITUTE AN APPROVAL OF STORM DRAINAGE DESIGN, SIZE NOR LOCATION OF PIPES, RESTRICTORS, CHANNELS, OR STORMWATER FACILITIES. 11.ANY DEWATERING SYSTEM NECESSARY FOR THE CONSTRUCTION OF STORMWATER FACILITIES SHALL BE SUBMITTED TO THE CITY FOR REVIEW AND APPROVAL. 12.ANY AREAS OF EXPOSED SOILS, INCLUDING ROADWAY EMBANKMENTS, THAT WILL NOT BE DISTURBED FOR TWO DAYS DURING THE WET SEASON (OCTOBER 1ST THROUGH APRIL 30TH) OR SEVEN DAYS DURING THE DRY SEASON (MAY 1ST THROUGH SEPTEMBER 30TH) SHALL BE IMMEDIATELY STABILIZED WITH THE APPROVED ESC COVER METHODS (E.G., SEEDING, MULCHING, PLASTIC COVERING, ETC.) IN CONFORMANCE WITH APPENDIX D OF THE RSWDM. 13.WET SEASON ESC REQUIREMENTS APPLY TO ALL CONSTRUCTION SITES BETWEEN OCTOBER 1ST AND APRIL 30TH, UNLESS OTHERWISE APPROVED BY THE CITY. 14.ANY AREA NEEDING ADDITIONAL ESC MEASURES, NOT REQUIRING IMMEDIATE ATTENTION, SHALL BE ADDRESSED WITHIN SEVEN (7) DAYS. 15.THE ESC BMPS ON INACTIVE SITES SHALL BE INSPECTED AND MAINTAINED AT A MINIMUM OF ONCE A MONTH OR WITHIN 24 HOURS FOLLOWING A STORM EVENT. INSPECTION AND MAINTENANCE SHALL OCCUR MORE FREQUENTLY AS REQUIRED BY THE CITY. 16.BEFORE COMMENCEMENT OF ANY CONSTRUCTION ACTIVITY, CATCH BASIN INSERTS PER THE CITY STANDARD PLANS 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 INLET WILL BE CONVEYED TO A SEDIMENT POND OR TRAP. ALL CATCH BASIN INSERTS SHALL BE PERIODICALLY INSPECTED AND REPLACED AS NECESSARY TO ENSURE FULLY FUNCTIONING CONDITION. 17.AT NO TIME SHALL SEDIMENT ACCUMULATION EXCEED 2/3 OF THE CAPACITY OF THE CATCH BASIN SUMP. ALL CATCH BASINS AND CONVEYANCE LINES SHALL BE CLEANED PRIOR TO PAVING. THE CLEANING OPERATION SHALL NOT FLUSH SEDIMENT-LADEN WATER INTO THE DOWNSTREAM SYSTEM. 18.ANY PERMANENT STORMWATER FACILITY USED AS A TEMPORARY SETTLING BASIN SHALL BE MODIFIED WITH THE NECESSARY ESC BMPS AND SHALL PROVIDE ADEQUATE STORAGE CAPACITY. IF THE PERMANENT FACILITY IS TO FUNCTION ULTIMATELY AS AN INFILTRATION SYSTEM, THE TEMPORARY FACILITY SHALL BE ROUGH GRADED SO THAT THE BOTTOM AND SIDES ARE AT LEAST THREE FEET ABOVE THE FINAL GRADE OF THE PERMANENT FACILITY. 19.AREAS DESIGNATED ON THE PLAN(S) CONTAINING EXISTING STORMWATER FACILITIES OR ON-SITE BMPS (AMENDED SOILS, BIORETENTION, PERMEABLE PAVEMENT, ETC.) SHALL BE CLEARLY FENCED AND PROTECTED USING ESC BMPS TO AVOID SEDIMENTATION AND COMPACTION DURING CONSTRUCTION. 20.PRIOR TO THE BEGINNING OF THE WET SEASON (OCTOBER 1ST), ALL DISTURBED AREAS SHALL BE INSPECTED TO IDENTIFY WHICH ONES SHALL BE SODDED OR SEEDED IN PREPARATION FOR THE WINTER RAINS. DISTURBED AREAS SHALL BE SODDED OR SEEDED WITHIN ONE WEEK OF THE BEGINNING OF THE WET SEASON. AN EXHIBIT OF THOSE AREAS TO BE SODDED OR SEEDED AND THOSE AREAS TO REMAIN UNCOVERED SHALL BE SUBMITTED TO THE CITY FOR REVIEW. 21.PRIOR TO FINAL CONSTRUCTION ACCEPTANCE, THE PROJECT SITE SHALL BE STABILIZED TO PREVENT SEDIMENT-LADEN WATER FROM LEAVING THE PROJECT SITE, ALL ESC BMPS SHALL BE REMOVED, AND STORMWATER CONVEYANCE SYSTEMS, FACILITIES, AND ON-SITE BMPS SHALL BE RESTORED TO THEIR FULLY FUNCTIONING CONDITION. ALL DISTURBED AREAS OF THE PROJECT SITE SHALL BE VEGETATED OR OTHERWISE PERMANENTLY STABILIZED. AT A MINIMUM, DISTURBED AREAS SHALL BE SODDED OR SEEDED AND MULCHED TO ENSURE THAT SUFFICIENT COVER WILL DEVELOP SHORTLY AFTER FINAL APPROVAL. MULCH WITHOUT SEEDING IS ADEQUATE FOR SMALL AREAS TO BE LANDSCAPED BEFORE OCTOBER 1ST. 22.ROCKERIES ARE CONSIDERED TO BE A METHOD OF BANK STABILIZATION AND EROSION CONTROL. ROCKERIES SHALL NOT BE CONSTRUCTED TO SERVE AS RETAINING WALLS. ALL ROCKERIES IN CITY ROAD RIGHT-OF-WAY SHALL BE CONSTRUCTED IN ACCORDANCE WITH CITY STANDARDS. ROCKERIES OUTSIDE OF ROAD RIGHT-OF-WAY SHALL BE CONSTRUCTED IN ACCORDANCE WITH THE INTERNATIONAL BUILDING CODE. EROSION CONTROL (ESC) STANDARD PLAN NOTES 8 CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 TESC NOTES AND DETAILS C3.2 9 CONSTRUCTION SEQUENCE 1.SCHEDULE AND ATTEND PRE-CONSTRUCTION MEETING WITH STEMEN'S ENVIRONMENTAL, THE ENGINEER, OWNER'S REPRESENTATIVE, GEOTECHNICAL ENGINEER, CESCL, AND CITY INSPECTOR. 2.POST SIGN WITH NAME AND PHONE NUMBER OF ESC SUPERVISOR (MAY BE CONSOLIDATED WITH THE REQUIRED NOTICE OF CONSTRUCTION SIGN). 3.SECURE THE PROJECT SITE WITH SECURITY FENCING. 4.CHECK AND FIX EXISTING PERIMETER FABRIC FENCING. 5.INSTALL CATCH BASIN PROTECTION ALONG FRONTAGE. 6.MAINTAIN EXISTING AND PROVIDE NEW CONSTRUCTION ENTRANCE(S). 7.DELIVER AND CONFIGURE STORMWATER STORAGE TANKS. POTHOLE SIDE SEWER AND CONNECT TANKS FOR DISCHARGE. SEWER DISCHARGE SHALL ADHERE TO THE KING COUNTY SEWER DISCHARGE PERMIT. 8.GRADE AND STABILIZE ONSITE CONSTRUCTION ROADS IF NECESSARY FOR TRUCK TRAFFIC. 9.CONSTRUCT SURFACE WATER CONTROLS (INTERCEPTOR DIKES, PIPE SLOPE DRAINS, ETC.) SIMULTANEOUSLY WITH CLEARING AND GRADING FOR PROJECT DEVELOPMENT. 10.MAINTAIN EROSION CONTROL MEASURES IN ACCORDANCE WITH APPENDIX D OF THE 2017 CITY OF RENTON SURFACE WATER DESIGN MANUAL (2017 RSWDM) AND MANUFACTURER'S RECOMMENDATIONS. 11.RELOCATE EROSION CONTROL MEASURES OR INSTALL NEW MEASURES SO THAT AS SITE CONDITIONS CHANGE THE EROSION AND SEDIMENT CONTROL IS ALWAYS IN ACCORDANCE WITH THE CITY'S EROSION AND SEDIMENT CONTROL STANDARDS. 12.COVER ALL AREAS THAT WILL BE UNWORKED FOR MORE THAN SEVEN DAYS DURING THE DRY SEASON OR TWO DAYS DURING THE WET SEASON WITH STRAW, WOOD FIBER MULCH, COMPOST, PLASTIC SHEETING, OR EQUIVALENT. 13.STABILIZE ALL AREAS THAT REACH FINAL GRADE WITHIN SEVEN DAYS. 14.STABILIZE ANY AREAS TO REMAIN UNWORKED FOR MORE THAN 30 DAYS. STABILIZE RECLAIMED AREAS WITH ROCK SURFACING. 14. THE WETLAND BUFFER SHALL BE RESTORED IN ACCORDANCE WITH THE LANDSCAPE PLANS. 15.UPON COMPLETION OF THE PROJECT, ALL DISTURBED AREAS MUST BE STABILIZED AND BMPS REMOVED IF APPROPRIATE.Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-TESC.dwg9 T EAST VALLEY ROADS.R. 167SW 34TH ST Civil Engineers Structural Engineers Landscape Architects Community Planners Land Surveyors Neighbors WALKER DEALERSHIP 2180100.10 N GRAPHIC SCALE 0 80 160 1" = 80 FEET 40 Q:\2018\2180100\10_CIV\CAD\EXHIBITS\20181005 - Temp Ponding.dwg ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendix B Select King County Source Control BMPs ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendix C Inspection and Maintenance Report Forms ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendix D Geotechnical Report Migizi Group, Inc., April 27, 2018 Geotechnical Engineering Report Walker Renton Auto Dealership 3400 East Valley Road Renton, Washington P/N 302305-9067 April 27, 2018 prepared for: HHJ Architects, PLLC Attention: Roger Hansen 601 St Helens Tacoma Washington 98402 prepared by: Migizi Group, Inc. PO Box 44840 Tacoma, Washington 98448 (253) 537-9400 MGI Project P1238-T18 i TABLE OF CONTENTS Page No. 1.0 SITE AND PROJECT DESCRIPTION .............................................................................................. 1 2.0 EXPLORATORY METHODS ............................................................................................................ 2 2.1 Auger Boring Procedures...................................................................................................... 3 3.0 SITE CONDITIONS ............................................................................................................................ 3 3.1 Surface Conditions ................................................................................................................. 3 3.2 Soil Conditions ....................................................................................................................... 4 3.3 Groundwater Conditions ...................................................................................................... 5 3.4 Seismic Conditions ................................................................................................................. 5 3.5 Liquefaction Potential ........................................................................................................... 5 3.6 Infiltration Conditions ........................................................................................................... 6 4.0 CONCLUSIONS AND RECOMMENDATIONS............................................................................ 6 4.1 Site Preparation ...................................................................................................................... 7 4.2 Augercast Piles ....................................................................................................................... 9 4.3 Slab-On-Grade-Floors .......................................................................................................... 11 4.4 Drainage Systems ................................................................................................................. 11 4.5 Asphalt Pavement ................................................................................................................ 12 4.6 Structural Fill ........................................................................................................................ 13 5.0 RECOMMENDED ADDITIONAL SERVICES ............................................................................. 14 6.0 CLOSURE ........................................................................................................................................... 15 List of Tables Table 1. Approximate Locations and Depth of Explorations .............................................................................. 2 Table 2. Recommended Allowable Pile Capacities ............................................................................................... 9 List of Figures Figure 1. Topographic and Location Map Figure 2. Site and Exploration Plan APPENDIX A Soil Classification Chart and Key to Test Data .................................................................................................. A-1 Log of Auger Borings B-1 and B-2 ............................................................................................................. A-2…A-3 Page 1 of 15 MIGIZI GROUP, INC. PO Box 44840 PHONE (253) 537-9400 Tacoma, Washington 98448 FAX (253) 537-9401 April 17, 2018 HHJ Architects, PLLC 601 St Helens Tacoma, Washington 98402 Attention: Roger Hansen Subject: Geotechnical Engineering Report Walker Renton Auto Dealership 3400 East Valley Road Renton, Washington P/N 302305-9067 MGI Project P1238-T18 Dear Mr. Hansen: Migizi Group, Inc. (MGI) is pleased to submit this report describing the results of our geotechnical engineering evaluation of the proposed Walker Renton Auto Dealership development at 3400 East Valley Road in Renton, Washington. This report has been prepared for the exclusive use of HHJ Architects, PLLC, and their consultants, for specific application to this project, in accordance with generally accepted geotechnical engineering practice. 1.0 SITE AND PROJECT DESCRIPTION The project site consists of an irregularly-shaped, 5.65-acre, commercially-zoned parcel located towards the south end of the city limits of Renton, Washington, as shown on the enclosed Topographic and Location Map (Figure 1). The subject property is situated between East Valley Road and SR-167 in a heavily developed commercial area. The project site has previously been developed, being utilized as an auto junk yard. A 4,000-sf warehouse building and 1,160 sf radiator shop are still present towards the northwest corner of the project area, as well as paved parking facilities. The remainder of the site had been graded to accommodate storage of vehicles and auto parts, though these have previously been removed from the site. During this initial development of the site, the wetland area along the west side of SR-167 had been severely damaged, and in many cases had been filled. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 2 of 15 It is our understanding that improvement plans involve the demolition of existing site features and the repurposing of the property as an auto dealership. This will involve the construction of a new 50,000 to 60,000 sf two-story, wood-framed structure towards the center of the property, in addition to extensive pavements surrounding this facility. The new structure will contain a showroom/sales area, business offices, parts sales and storage, service and shop regions, storage and other supportive areas. In addition to the aforementioned improvements, the subject development will also entail the restoration of the existing wetland which was damaged by previous actions at the east side of the site along SR-167, and the establishment and maintaining of a new 75-foot buffer area from this wetland. Environmental cleanup will be performed in conjunction with new construction as appropriate, based on recommendations provided by Kane Environmental. 2.0 EXPLORATORY METHODS We explored surface and subsurface conditions at the project site on March 16, 2018. Our exploration and evaluation program comprised the following elements: • Surface reconnaissance of the site; • Two auger boring explorations (designated B-1 and B-2), advanced on March 16, 2016; and • A review of published geologic and seismologic maps and literature. Table 1 summarizes the approximate functional locations and termination depths of our subsurface explorations, and Figure 2 depicts their approximate relative locations. The following sections describe the procedures used for excavation of test pits. TABLE 1 APPROXIMATE LOCATIONS AND DEPTHS OF EXPLORATIONS Exploration Functional Location Termination Depth (feet) B-1 B-2 East end of proposed building footprint Southwest corner of proposed building footprint 61½ 51½ The specific number and locations of our explorations were selected in relation to the existing site features, under the constraints of surface access, underground utility conflicts, and budget considerations. It should be realized that the explorations performed and utilized for this eva luation reveal subsurface conditions only at discrete locations across the project site and that actual conditions in other areas could vary. Furthermore, the nature and extent of any such variations would not become evident until additional explorations are performed or until construction activities have begun. If significant variations are observed at that time, we may need to modify our conclusions and recommendations contained in this report to reflect the actual site conditions. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 3 of 15 2.1 Auger Boring Procedures Our exploratory borings were advanced through the soil with a hollow-stem auger, using a truck- mounted drill rig, operated by an independent drilling firm working under subcontract to MGI. An engineering geologist from our firm continuously observed the boring, logged the subsurface conditions, and collected representative soil samples. All samples were stored in watertight containers and later transported to a laboratory for further visual examination and testing. After the borings were completed, the borehole was backfilled in accordance with state requirements. Throughout the drilling operation, soil samples were obtained at 2½ to 5-foot depth intervals by means of the Standard Penetration Test (SPT) per American Society for Testing and Materials (ASTM:D-1586), or using a large split-spoon sampler. This testing and sampling procedure consists of driving a standard 2-inch-outside-diameter steel split-spoon sampler 18 inches into the soil with a 140-pound hammer free-falling 30 inches. The number of blows struck during the final 12 inches is recorded on the boring log. If a total of 50 blows are struck within any 6 -inch interval, the driving is stopped, and the blow count is recorded as 50 blows for the actual penetration distance. The resulting blow count values indicate the relative density of granular soils and the relative consistency of cohesive soils. The soils were classified visually in general accordance with the system described in Figure A-1, which includes a key to our exploration logs. Summary logs of our explorations are included as Figures A-2 and A-3. The enclosed boring logs describe the vertical sequence of soils and materials encountered in the borings, based primarily on our field classifications and supported by our subsequent laboratory examination and testing. Where a soil contact was observed to be gradational, our logs indicate the average contact depth. Where a soil type changed between sample intervals, we inferred the contact depth. Our logs also graphically indicate the blow count, sample type, sample number, and approximate depth of each soil sample obtained from the boring, as well as any laboratory tests performed on these soil samples. If any groundwater was encountered in the borehole, the approximate groundwater depth is depicted on the boring logs. Groundwater depth estimates are typically based on the moisture content of soil samples, the wetted height on the drilling rods, and the water level measured in the borehole after the auger has been extracted. 3.0 SITE CONDITIONS The following sections present our observations, measurements, findings, and interpretations regarding, surface, soil, groundwater, and infiltration conditions. 3.1 Surface Conditions As previously indicated, the project site consists of an irregularly-shaped, 5.65-acre, commercially-zoned parcel, located towards the south end of the city limits of Renton, between East Valley Road and SR-167 in a heavily developed commercial area. The site is bound on the north by East Valley RV & Boat Storage, on the south by the Brickman Group storage yard, on the west by East Valley Road, and on the east by SR 167. The northwest corner of the project area retains an existing 4,000-sf warehouse building, a 1,160-sf radiator shop, and asphalt pavement parking facilities. The aforementioned structures were originally constructed in 1996. The remainder of the site had been graded and resurfaced with recycled concrete, to serve as a storage HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 4 of 15 location for automobile parts and debris. The entirety of the site is enclosed by a chain-link fence, with access to the interior being gained through a locked gate. Topographically, the site is relatively level with minimal grade changes being observed over its extent. Purportedly, the eastern margin of the site is a historic wetland region, which had been infringed upon by past developments. This portion of the site served as part of the larger basin for Panther Creek, which travels north and south of the project area along the east side of SR 167. No vegetation was observed on site outside of scattered weeds which have taken root within the existing gravel surfacing. No hydrological features were observed on site, such as seeps, springs, ponds and streams. Scattered ponding was observed across the southwest portion of the site at the time of our site visit. We believe that this is seasonal in nature, and not indicative of hydrogeological conditions onsite. 3.2 Soil Conditions We observed subsurface conditions through the advancement of two geotechnical borings within the footprint of the 50,000 to 60,000-sf structure proposed towards the interior of the site. These explorations extended 51½ to 61½ feet below existing grade, respectively, encountering relatively consistent subgrade conditions. Approximately 5 feet of fill soils were observed at surface elevations in both of our explorations, ranging in composition from recycled concrete to gravelly silty sand. Both of these material types were encountered in a medium dense to dense in situ condition. Underlying these fill soils, we encountered native, alluvial deposits. With depth, alluvial deposits encountered onsite exhibited alternating layers of poorly consolidated fine-grained soils, and moderately consolidated granular soils; highlighting the shifting, localized depositional environment across the project area. The uppermost fine-grained zone, observed immediately below existing fill material, contained a significant organic component. Both of our explorations encountered, below a depth of ± 31 feet, through their respective termination depths, moderately dense, fine silty sand. In the Geologic Map of the Tacoma 1:100,000-scale Quadrangle, as prepared by the Washington State Department of Natural Resources Division of Geology and Earth Resources (WSDNR) (2015), the project site is mapped as containing Qp, or peat, which directly overlies Qa, or Quaternary Alluvium. Peat, as per this publication, is described as loose, locally very soft and wet, organic and organic rich sediment, including muck, silt and clay. Alluvium, as it pertains to the geographic setting of the project area, refers to sedimentary deposits associated with the flood plains of the Duwamish/Green Rivers, and are typically comprised of loose, stratified to massively bedded fluvial silt, sand, and gravel that is typically, well rounded and moderately to well sorted and locally includes sandy to silty estuarine deposits. Our field observations and subsurface explorations generally conform with the geologic classification of the site performed by the WSDNR. The enclosed exploration logs (Appendix A) provide a detailed description of the soil strata encountered in our subsurface explorations. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 5 of 15 3.3 Groundwater Conditions At the time of our reconnaissance and subsurface explorations (March 16, 2018), we encountered groundwater seepage at a depth which ranged from 8 to 15 feet below existing grade . Groundwater levels were generally higher towards the southwest corner of the project area, where significant surficial ponding was observed at the time of our site visit. Given the fact that our explorations were performed within what is generally considered the rainy season (October 1st through April 30th), we do not anticipate that groundwater will rise much higher than that which we observed. Groundwater levels will fluctuate with localized geology and precipitation. 3.4 Seismic Conditions Based on our analysis of subsurface exploration logs and our review of published geologic maps, we interpret the onsite soil conditions to generally correspond with site class E, as defined by Table 20.3-1 in ASCE 7, per the 2015 International Building Code (IBC). Using 2015 IBC information on the USGS Design Summary Report website, Risk Category I/II/III seismic parameters for the site are as follows: Ss = 1.418 g SMS = 1.276 g SDS = 0.851 g S1 = 0.528 g SM1 = 1.266 g SD1 = 0.844 g Using the 2015 IBC information, MCER Response Spectrum Graph on the USGS Design Summary Report website, Risk Category I/II/III, Sa at a period of 0.2 seconds is 1.28 g and Sa at a period of 1.0 seconds is 1.27 g. The Design Response Spectrum Graph from the same website, using the same IBC information and Risk Category, Sa at a period of 0.2 seconds is 0.85 g and Sa at a period of 1.0 seconds is 0.84 g. 3.5 Liquefaction Potential Liquefaction is a sudden increase in pore water pressure and a sudden loss of soil shear strength caused by shear strains, as could result from an earthquake. Research has shown that saturated, loose, fine to medium sands with a fines (silt and clay) content less than about 20 percent are most susceptible to liquefaction. Subsurface explorations performed for this project indicate that the site is underlain by poorly consolidated alluvial soils, ranging in composition from a fine sand with silt to sandy silt; with intermittent layers or lenses of peat. Given the geologic/hydrogeolgic conditions of the project area, we interpret this site as having a moderate susceptibility to liquefaction. In Section 4.2 of this report, we provide recommendations for the preparation of the foundation subgrade which would help mitigate much of this risk, however, during a large-scale seismic event, some degree of liquefaction and related post-construction settlement should be anticipated. We recommend that the structure be designed to prevent catastrophic collapse during a seismic event. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 6 of 15 3.6 Infiltration Conditions As indicated in the Soil and Groundwater Conditions sections of this report, the site is underlain by fill material and poorly-drained, slowly permeable, alluvial soils, with a shallow groundwater table. As such, we do not interpret infiltration as being feasible for this project, and recommend that site produced stormwater be diverted to an existing storm system, managed through detention, or other appropriate means. 4.0 CONCLUSIONS AND RECOMMENDATIONS It is our understanding that improvement plans involve the demolition of existing site features and the repurposing of the property as an auto dealership. This will involve the constructi on of a new 50,000 to 60,000 sf two-story, wood-framed structure towards the center of the property, in addition to extensive pavements surrounding this facility. The new structure will contain a showroom/sales area, business offices, parts sales and storage, service and shop regions, storage and other supportive areas. In addition to the aforementioned improvements, the subject development will also entail the restoration of the existing wetland which was damaged by previous actions at the east side of the site along SR-167, and the establishment and maintaining of a new 75-foot buffer area from this wetland. Environmental cleanup will be performed in conjunction with new construction as appropriate, based on recommendations provided by Kane Environmental. We offer the following recommendations: • Feasibility: Based on our field explorations, research, and evaluations, the proposed structures and pavements appear feasible from a geotechnical standpoint. • Foundation Options: In order to address soil and liquefaction conditions within the proposed expansion area and limit settlement of the addition and new settlement of the existing structure, we recommend that all foundation elements be supported by augercast piles. Recommendations for augercast pile foundations are presented in Section 4.2. • Floor Options: In our opinion, soil-supported slab-on-grade floors can be used if the subgrades are properly prepared. However, there is a potential that liquefaction settlement of the underlying site soils could cause cracking and damage to soil-supported slab-on-grade floors during the design earthquake. If the potential for damage is not acceptable, we recommend that floor slabs be structurally supported. If used, soil supported floor sections should bear on medium dense or denser native soils or on properly compacted structural fill that extends down to medium dense or denser native soil. Recommendations for slab-on-grade floors are included in Section 4.3. Fill underlying floor slabs should be compacted to 95 percent (ASTM:D-1557). • Pavement: We recommend a conventional pavement section comprised of asphalt concrete over crushed rock base course over properly prepared subgrade. Because soft soils immediately underlie proposed pavements, subgrade preparation HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 7 of 15 generally should consist of an over-excavation of two feet, compaction of exposed subgrade soils, then replacement with a suitable structural fill. Compaction should be done in accordance with the structural fill recommendations presented in Section 4.6. All soil subgrades below 24 inches should be thoroughly compacted, then proof- rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be over excavated to an additional maximum depth of 12 inches and replaced with a suitable structural fill material. The following sections of this report present our specific geotechnical conclusions and recommendations concerning site preparation, spread footings, slab-on-grade floors, pavement, and structural fill. The Washington State Department of Transportation (WSDOT) Standard Specifications and Standard Plans cited herein refer to WSDOT publications M41-10, Standard Specifications for Road, Bridge, and Municipal Construction, and M21 -01, Standard Plans for Road, Bridge, and Municipal Construction, respectively. 4.1 Site Preparation Preparation of the project site should involve erosion control, temporary drainage, clearing, stripping, excavations, cutting, subgrade compaction, and filling. Erosion Control: Before new construction begins, an appropriate erosion control system should be installed. This system should collect and filter all surface water runoff through silt fencing. We anticipate a system of berms and drainage ditches around construction areas will provide an adequate collection system. Silt fencing fabric should meet the requirements of WSDOT Standard Specification 9-33.2 Table 3. In addition, silt fencing should embed a minimum of 6 inches below existing grade. An erosion control system requires occasional observation and maintenance. Specifically, holes in the filter and areas where the filter has shifted above ground surface should be replaced or repaired as soon as they are identified. Temporary Drainage: We recommend intercepting and diverting any potential sources of surface or near-surface water within the construction zones before stripping begins. Because the selection of an appropriate drainage system will depend on the water quantity, season, weather conditions, construction sequence, and contractor's methods, final decisions regarding drainage systems are best made in the field at the time of construction. Based on our current understanding of the construction plans, surface and subsurface conditions, we anticipate that curbs, berms, or ditches placed around the work areas will adequately intercept surface water runoff. Clearing and Stripping: After surface and near-surface water sources have been controlled, sod, topsoil, and root-rich soil should be stripped from the site. Our explorations and field observations indicate that no significant organic horizon is observed at surface elevations across the project area. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 8 of 15 Site Excavations: Based on our explorations, we expect that excavations will encounter moderately consolidated fill soils at shallow elevations, and poorly consolidated alluvial soils immediately beneath this material, both of which can be readily excavated using standard excavation equipment. Dewatering: Groundwater seepage was encountered in both of our subsurface explorations at a depth of 8 to 15 feet below existing grade, with higher groundwater tables being observed across regions exhibiting surficial ponding. If groundwater is encountered in excavations above the water table, or slightly below, we anticipate that an internal system of ditches, sumpholes, and pumps will be adequate to temporarily dewater shallow excavations. For excavations significantly below the water table, we anticipate that expensive dewatering equipment, such as well points, will be required to temporarily dewater excavations. Temporary Cut Slopes: All temporary soil slopes associated with site cutting or excavations should be adequately inclined to prevent sloughing and collapse. Temporary cut slopes in site soils should be no steeper than 1½H:1V and should conform to Washington Industrial Safety and Health Act (WISHA) regulations. Subgrade Compaction: Exposed subgrades for the foundations of the planned structures should be compacted to a firm, unyielding state before new concrete or fill soils are placed. Any localized zones of looser granular soils observed within a subgrade should be compacted to a density commensurate with the surrounding soils. In contrast, any organic, soft, or pumping soils observed within a subgrade should be over-excavated and replaced with a suitable structural fill material. Site Filling: Our conclusions regarding the reuse of onsite soils and our comments regarding wet- weather filling are presented subsequently. Regardless of soil type, all fill should be placed and compacted according to our recommendations presented in the Structural Fill section of this report. Specifically, building pad fill soil should be compacted to a uniform density of at least 95 percent (based on ASTM:D-1557). Onsite Soils: We offer the following evaluation of these onsite soils in relation to potential use as structural fill: • Surficial Organic Soil and Organic-Rich Topsoil: Where encountered, surficial organic soils, like duff, topsoil, root-rich soil, and organic-rich fill soils are not suitable for use as structural fill under any circumstances, due to high organic content. Consequently, this material can be used only for non-structural purposes, such as in landscaping areas. • Existing Fill Material: As described in the Soil Conditions section of this report, the uppermost 5-feet of soils encountered onsite are comprised of existing fill material placed during the original site development. This material ranged in composition between recycled concrete and gravelly silty sand. These materials should be considered moderately sensitive, and reuse should be confined to periods of extended dry weather. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 9 of 15 • Alluvial Soils: Underlying existing fill material, we encountered native alluvial soils exhibiting alternating layers of poorly consolidated fine -grained soils and moderately consolidated granular soils. The uppermost fine -grained layer is the only native soils which could be feasibly reused as structural fill throughout the course of this project. This soil group contains a high organic content, is extremely moisture sensitive, and is generally encountered in an over-saturated condition. Reuse of this material should be limited to landscaping areas. Permanent Slopes: All permanent cut slopes and fill slopes should be adequately inclined to reduce long-term raveling, sloughing, and erosion. We generally recommend that no permanent slopes be steeper than 2H:1V. For all soil types, the use of flatter slopes (such as 2½H:1V) would further reduce long-term erosion and facilitate revegetation. Slope Protection: We recommend that a permanent berm, swale, or curb be constructed along the top edge of all permanent slopes to intercept surface flow. Also, a hardy vegetative groundcover should be established as soon as feasible, to further protect the slopes from runoff water erosion. Alternatively, permanent slopes could be armored with quarry spalls or a geosynthetic erosion mat. 4.2 Augercast Piles Based on the soil conditions discussed above, we recommend that the new building be supported on augercast piles installed to a depth of 55 feet below the existing ground surface in the medium dense silty sands. The following table provides estimated allowable design capacities for 14-inch, 16-inch, and 18-inch diameter augercast concrete pilings installed to the aforementioned embedment depth: TABLE 2 RECOMMENDED ALLOWABLE PILE CAPACITIES 14-INCH, 16-INCH AND 18-INCH DIAMETER AUGERCAST CONCRETE PILES Pile Diameter (inches) Depth Below Existing Ground Surface (feet) Downward Capacity (tons) Uplift Capacity (tons) 14 55 66 26 16 55 80 30 18 55 98 34 The allowable pile capacities presented above apply to all long-term live and dead loads and may be increased by one-third when considering short-term loads such as wind or seismic influence. The allowable pile capacities are based on the strength of the supporting soils for the penetrations indicated and include a factor of safety of at least 2. The allowable uplift capacities indicated for augercast piles may be used provided that a reinforcing bar is installed the entire length of the pile. This bar should be centered in the pile. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 10 of 15 Static pile settlements are expected to be essentially elastic in nature and occur as loads are applied. Total static settlement of piles constructed as recommended are not expected to exceed 1 inch, while differential static settlements between comparably loaded piles are not expected to exceed about 50 percent of this value. The pile capacities provided above apply to single piles. If piles within groups are spaced at least three pile diameters on center, no reduction for pile group action need be made. The structural characteristics of the pile materials and allowable internal stresses may impose more stringent limitations and should be evaluated by the structural engineer. Lateral loadings due to wind or seismic forces can be resisted by uplift or lateral loading on the piles, or lateral soil resistance of the pile cap. The manner in which these loads are transferred into the piles will be a function of the design of the foundation system. Passive soil resistance of the pile cap may be computed using an equivalent fluid density of 220 pcf (pounds per cubic foot) for a level backfill surface, provided the backfill around the pile cap is compacted to at least 95 percent of maximum dry density per American Society for Testing and Materials (ASTM) D-1557. This value incorporates a factor of safety of about 1.5. Lateral capacities for augercast piling are dependent upon the characteristics of the reinforcing steel and the coefficient of subgrade reaction for the surrounding soils. We recommend that the pile stiffness, T, be computed using the formula T = (EI/f)1/5 where E equals the pile modulus of elasticity, I equals the pile moment of inertia, and f equals the soil coefficient of subgrade reaction. A value of 6 tcf (tons per cubic foot) should be used for f. For the recommended penetration, the maximum moment for piles fixed against rotation at the ground surface will occur at a depth equal to about 1.8 T and the magnitude of this moment, M, can be computed using the formula M = 0.25 PT where P is the lateral force applied at the ground surface. The moment will decrease to zero at a depth of about 4.5 T. The maximum pile deflection at the ground surface can be computed using the formula D = 0.93 (PT3/EI). Pile Installation: Augercast (cast-in-place) concrete piles should be installed using a continuous- flight, hollow-stem auger. As is common practice, the pile grout would be pumped under pressure through the hollow-stem as the auger is withdrawn. Reinforcing steel for bending and uplift would be placed in the fresh grout column immediately after withdrawal of the auger. No direct information regarding the capacity of augercast piles (e.g., driving resistance data) is obtained while this type of pile is being installed. Therefore, it is particularly important that the installation of augercast piles be carefully monitored by a qualified individual working under the direct supervision of a geotechnical engineer. It should be noted that the recommended pile penetration and allowable capacities presented above assumed uniform soil conditions. There may be unexpected variations in the depth and characteristics of the supporting soils across the site. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 11 of 15 Accordingly, we recommend that pile installation be monitored by a member of our staff who will observe installation procedures and evaluate the adequacy of individual pile installations. 4.3 Slab-On-Grade Floors In our opinion, soil-supported slab-on-grade floors can be used if the subgrades are properly prepared. However, there is a potential that liquefaction settlement of the underlying site soils could cause cracking and damage to soil-supported slab-on-grade floors during the design earthquake. If the potential for damage is not acceptable, we recommend that floor slabs be structurally supported. We offer the following comments and recommendations concerning soil-supported slab-on- grade floors. Floor Subbase: We recommend over-excavation of slab-on-grade floor subgrades to a minimum depth of 2 feet, then placement of properly compacted structural fill as a floor subbase. If floor construction occurs during wet conditions, it is likely that a geotextile fabric, placed between the structural fill floor subbase and native soils, will be necessary. All subbase fill should be compacted to a density of at least 95 percent (based on ASTM:D-1557). Capillary Break and Vapor Barrier: To retard the upward wicking of moisture beneath the floor slab, we recommend that a capillary break be placed over the subgrade. Ideally, this capillary break would consist of a 4-inch-thick layer of pea gravel or other clean, uniform, well-rounded gravel, such as “Gravel Backfill for Drains” per WSDOT Standard Specification 9-03.12(4), but clean angular gravel can be used if it adequately prevents capillary wicking. In addition, a layer of plastic sheeting (such as Crosstuff, Visqueen, or Moistop) should be placed over the capillary break to serve as a vapor barrier. During subsequent casting of the concrete slab, the contractor should exercise care to avoid puncturing this vapor barrier. Vertical Deflections: Due to elastic compression of subgrades, soil-supported slab-on-grade floors can deflect downwards when vertical loads are applied. In our opinion, a subgrade reaction modulus of 140 pounds per cubic inch can be used to estimate such deflections. 4.4 Drainage Systems In our opinion, the proposed expansion area should be provided with a permanent drainage system to reduce the risk of future moisture problems. We offer the following recommendations and comments for drainage design and construction purposes. Perimeter Drains: We recommend that the structure be encircled with a perimeter drain system to collect seepage water. This drain should consist of a 4-inch-diameter perforated pipe within an envelope of pea gravel or washed rock, extending at least 6 inches on all sides of the pipe, and the gravel envelope should be wrapped with filter fabric to reduce the migration of fines from the surrounding soils. Ideally, the drain invert would be installed no more than 8 inches above the base of the perimeter footings. HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 12 of 15 Subfloor Drains: We recommend that subfloor drains be included beneath the new building. These subfloor drains should consist of 4-inch-diameter perforated pipes surrounded by at least 6 inches of pea gravel and enveloped with filter fabric. A pattern of parallel pipes spaced no more than 20 feet apart and having inverts located about 12 inches below the capillary break layer would be appropriate, in our opinion. Discharge Considerations: If possible, all perimeter drains should discharge to a sewer system or other suitable location by gravity flow. Check valves should be installed along any drainpipes that discharge to a sewer system to prevent sewage backflow into the drain system. If gravity flow is not feasible, a pump system is recommended to discharge any water that enters the drainage system. Runoff Water: Roof-runoff and surface-runoff water should not discharge into the perimeter drain system. Instead, these sources should discharge into separate tightline pipes and be routed away from the building to a storm drain or other appropriate location. Grading and Capping: Final site grades should slope downward away from the buildings so that runoff water will flow by gravity to suitable collection points, rather than ponding near the building. Ideally, the area surrounding the building would be capped with concrete, asphalt, or low-permeability (silty) soils to minimize or preclude surface-water infiltration. 4.5 Asphalt Pavement Since asphalt pavements will be expanded during the course of the proposed development, we offer the following comments and recommendations for pavement design and construction. Subgrade Preparation: After removal of any organics underlying pavements, we recommend a conventional pavement section comprised of an asphalt concrete pavement over a crushed rock base course over a properly prepared (compacted) subgrade or a granular subbase. Given the relative loose/soft soil conditions observed across the project area, we recommend the over- excavation of 24 inches of the existing subgrade material underlying the new pavement sections, and replacement with a suitable structural fill subbase. Given the extent of the proposed paving operation and corresponding earthwork activities, we recommend limiting the subgrade preparation to times of dry weather. All soil subgrades below 24 inches should be thoroughly compacted, then proof-rolled with a loaded dump truck or heavy compactor. Any localized zones of yielding subgrade disclosed during this proof-rolling operation should be over excavated to an additional maximum depth of 12 inches and replaced with a suitable structural fill material. All structural fill should be compacted according to our recommendations given in the Structural Fill section. Specifically, the upper 2 feet of soils underlying pavement section should be compacted to at least 95 percent (based on ASTM D-1557), and all soils below 2 feet should be compacted to at least 90 percent. Pavement Materials: For the base course, we recommend using imported crushed rock, such as "Crushed Surfacing Top Course” per WSDOT Standard Specification 9-03.9(3). If a subbase HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 13 of 15 course is needed, we recommend using imported, clean, well-graded sand and gravel such as “Ballast” or “Gravel Borrow” per WSDOT Standard Specifications 9-03.9(1) and 9-03.14, respectively. Conventional Asphalt Sections: A conventional pavement section typically comprises an asphalt concrete pavement over a crushed rock base course. We recommend using the following conventional pavement sections: Minimum Thickness Pavement Course Automobile Parking Area Driveways Areas Subject to Frequent Truck Traffic Asphalt Concrete Pavement 2 inches 3 inches 4 inches Crushed Rock Base 4 inches 6 inches 6 inches Granular Fill Subbase (if needed) 12 inches 24 inches 24 inches Compaction and Observation: All subbase and base course material should be compacted to at least 95 percent of the Modified Proctor maximum dry density (ASTM D-1557), and all asphalt concrete should be compacted to at least 92 percent of the Rice value (ASTM D-2041). We recommend that an MGI representative be retained to observe the compaction of each course before any overlying layer is placed. For the subbase and pavement course, compaction is best observed by means of frequent density testing. For the base course, methodology observations and hand-probing are more appropriate than density testing. Pavement Life and Maintenance: No asphalt pavement is maintenance-free. The above described pavement sections present our minimum recommendations for an average level of performan ce during a 20-year design life, therefore, an average level of maintenance will likely be required. Furthermore, a 20-year pavement life typically assumes that an overlay will be placed after about 10 years. Thicker asphalt and/or thicker base and subbase courses would offer better long-term performance, but would cost more initially; thinner courses would be more susceptible to “alligator” cracking and other failure modes. As such, pavement design can be considered a compromise between a high initial cost and low maintenance costs versus a low initial cost and higher maintenance costs. 4.6 Structural Fill The term "structural fill" refers to any material placed under foundations, retaining walls, slab - on-grade floors, sidewalks, pavements, and other structures. Our comments, conclusions, and recommendations concerning structural fill are presented in the following paragraphs. Materials: Typical structural fill materials include clean sand, gravel, pea gravel, washed rock, crushed rock, well-graded mixtures of sand and gravel (commonly called "gravel borrow" or "pit- run"), and miscellaneous mixtures of silt, sand, and gravel. Recycled asphalt, concrete, and glass, which are derived from pulverizing the parent materials, are also potentially useful as structural fill in certain applications. Utilizing recycled content may require approval from the Tacoma Pierce County Health Department for placement in an aquifer recharge area. Soils used for HHJ Architects, PLLC – Walker Renton Auto Dealership, 3400 E Valley Rd, Renton, WA April 27, 2018 Geotechnical Engineering Report P1238-T18 Migizi Group, Inc. Page 14 of 15 structural fill should not contain any organic matter or debris, nor any individual particles greater than about 6 inches in diameter. Fill Placement: Clean sand, gravel, crushed rock, soil mixtures, and recycled materials should be placed in horizontal lifts not exceeding 8 inches in loose thickness, and each lift should be thoroughly compacted with a mechanical compactor. Compaction Criteria: Using the Modified Proctor test (ASTM:D-1557) as a standard, we recommend that structural fill used for various onsite applications be compacted to the following minimum densities: Fill Application Minimum Compaction Slab-on-grade floor subgrade (upper 2 feet) Slab-on-grade floor subgrade (below 2 feet) Asphaltic pavement base and subbase Asphaltic pavement subgrade (upper 2 feet) Asphaltic pavement subgrade (below 2 feet) 95 percent 90 percent 95 percent 95 percent 90 percent Subgrade Observation and Compaction Testing: Regardless of material or location, all structural fill should be placed over firm, unyielding subgrades prepared in accordance with the Site Preparation section of this report. The condition of all subgrades should be observed by geotechnical personnel before filling or construction begins. Also, fill soil compaction should be verified by means of in-place density tests performed during fill placement so that adequacy of soil compaction efforts may be evaluated as earthwork progresses. Soil Moisture Considerations: The suitability of soils used for structural fill depends primarily on their grain-size distribution and moisture content when they are placed. As the "fines" content (that soil fraction passing the U.S. No. 200 Sieve) increases, soils become more sensitive t o small changes in moisture content. Soils containing more than about 5 percent fines (by weight) cannot be consistently compacted to a firm, unyielding condition when the moisture content is more than 2 percentage points above or below optimum. For fill placement during wet-weather site work, we recommend using "clean" fill, which refers to soils that have a fines content of 5 percent or less (by weight) based on the soil fraction passing the U.S. No. 4 Sieve. 5.0 RECOMMENDED ADDITIONAL SERVICES Because the future performance and integrity of the structural elements will depend largely on proper site preparation, drainage, fill placement, and construction procedures, monitoring and testing by experienced geotechnical personnel should be considered an integral part of the construction process. Consequently, we recommend that MGI be retained to provide the following post-report services: • Review all construction plans and specifications to verify that our design criteria presented in this report have been properly integrated into the design; • Prepare a letter summarizing all review comments (if required); APPROXIMATE SITE LOCATION P.O. Box 44840 Tacoma, WA 98448 Location Job Number Figure DateTitle 3400 East Valley Road Renton, WA P/N 302305-9067 Topographic and Location Map 1 04/06/18 P1238-T18 APPENDIX A SOIL CLASSIFICATION CHART AND KEY TO TEST DATA LOG OF AUGER BORINGS CLAYEY GRAVELS, POORLY GRADED GRAVEL-SAND-CLAY MIXTURES SILTS AND CLAYSCOARSE GRAINED SOILSMore than Half > #200 sieveLIQUID LIMIT LESS THAN 50 LIQUID LIMIT GREATER THAN 50 CLEAN GRAVELS WITH LITTLE OR NO FINES GRAVELS WITH OVER 15% FINES CLEAN SANDS WITH LITTLE OR NO FINES MORE THAN HALF COARSE FRACTION IS SMALLER THAN NO. 4 SIEVE MORE THAN HALF COARSE FRACTION IS LARGER THAN NO. 4 SIEVE INORGANIC SILTS, MICACEOUS OR DIATOMACIOUS FINE SANDY OR SILTY SOILS, ELASTIC SILTS ORGANIC CLAYS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY OH INORGANIC SILTS AND VERY FINE SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS, OR CLAYEY SILTS WITH SLIGHT PLASTICITY CH SILTY GRAVELS, POORLY GRADED GRAVEL-SAND-SILT MIXTURES SANDS SILTS AND CLAYS Figure A-1 INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYS, SANDY CLAYS, SILTY CLAYS, LEAN CLAYS E3RA R-Value Sieve Analysis Swell Test Cyclic Triaxial Unconsolidated Undrained Triaxial Torvane Shear Unconfined Compression (Shear Strength, ksf) Wash Analysis (with % Passing No. 200 Sieve) Water Level at Time of Drilling Water Level after Drilling(with date measured) RV SA SW TC TX TV UC (1.2) WA (20) Modified California Split Spoon Pushed Shelby Tube Auger Cuttings Grab Sample Sample Attempt with No Recovery Chemical Analysis Consolidation Compaction Direct Shear Permeability Pocket Penetrometer CA CN CP DS PM PP PtHIGHLY ORGANIC SOILS TYPICAL NAMES GRAVELS ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS WELL GRADED GRAVELS, GRAVEL-SAND MIXTURES MAJOR DIVISIONS PEAT AND OTHER HIGHLY ORGANIC SOILS WELL GRADED SANDS, GRAVELLY SANDS POORLY GRADED SANDS, GRAVELLY SANDS SILTY SANDS, POOORLY GRADED SAND-SILT MIXTURES CLAYEY SANDS, POORLY GRADED SAND-CLAY MIXTURES POORLY GRADED GRAVELS, GRAVEL-SAND MIXTURES SOIL CLASSIFICATION CHART AND KEY TO TEST DATA GW GP GM GC SW SP SM SC ML FINE GRAINED SOILSMore than Half < #200 sieveLGD A NNNN02 GINT US LAB.GPJ 11/4/05INORGANIC CLAYS OF HIGH PLASTICITY, FAT CLAYS CL OL MH SANDS WITH OVER 15% FINES SS S-1 SS S-2 SS S-3 SS S-4 SS S-5 SS S-6 SS S-7 SS S-8 6 6 12 12 12 18 18 18 11-19-12 (31) 6-3-6 (9) 3-3-4 (7) 1-2-2 (4) 2-1-2 (3) 2-5-6 (11) 2-3-12 (15) 4-1-1 (2) SM ML SM OH SM SP ML 2.0 5.5 7.0 9.0 13.0 17.5 31.0 Recycled Concrete (SM) Gray/brown silty sand with gravel (dense, damp) (Fill) (ML) Gray/brown silt with some organics (stiff, moist) (Alluvium) (SM) Gray silty sand with some gravel (loose, wet) (Alluvium) (OH) Gray organic silt (soft, wet) (Alluvium) (SM) Gray fine silty sand (very loose, wet) (Alluvium) (SP) Black fine to coarse sand (medium dense, wet) (Alluvium) With interbeds of silty sand (ML) Gray silt (soft, wet) (Alluvium) NOTES LOGGED BY ZLL DRILLING METHOD Truck Mounted Drill Rig DRILLING CONTRACTOR Holocene GROUND WATER LEVELS: CHECKED BY JEB DATE STARTED 3/16/18 COMPLETED 3/16/18 AT TIME OF DRILLING 15.00 ft AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE 4.25" HSAGROUND ELEVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 15 20 25 30 35 (Continued Next Page) PAGE 1 OF 2 Figure A-2 BORING NUMBER B-1 CLIENT HHJ Architects, PLLC PROJECT NUMBER P1238-T18 PROJECT NAME Walker Renton Auto Dealership Geotech Report PROJECT LOCATION 3400 East Valley Road, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 4/5/18 15:42 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1238-T18\P1238-T18 BORING LOGS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 RECOVERY (in)(RQD)BLOWCOUNTS(N VALUE)U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION SS S-9 SS S-10 SS S-11 SS S-12 SS S-13 SS S-14 18 18 18 18 18 18 1-2-2 (4) 0-4-6 (10) 3-5-5 (10) 0-4-8 (12) 10-8-10 (18) 3-4-5 (9) ML SM 40.5 61.5 (ML) Gray silt (soft, wet) (Alluvium) (continued) (SM) Gray fine silty sand (medium dense, wet) (Alluvium) Grades to loose Bottom of borehole at 61.5 feet.SAMPLE TYPENUMBERDEPTH(ft)35 40 45 50 55 60 PAGE 2 OF 2 Figure A-2 BORING NUMBER B-1 CLIENT HHJ Architects, PLLC PROJECT NUMBER P1238-T18 PROJECT NAME Walker Renton Auto Dealership Geotech Report PROJECT LOCATION 3400 East Valley Road, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 4/5/18 15:42 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1238-T18\P1238-T18 BORING LOGS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 RECOVERY (in)(RQD)BLOWCOUNTS(N VALUE)U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION SS S-1 SS S-2 SS S-3 SS S-4 SS S-5 SS S-6 SS S-7 SS S-8 6 12 18 12 18 18 18 18 6-2-2 (4) 1-0-0 (0) 5-5-8 (13) 5-3-3 (6) 7-8-10 (18) 2-3-7 (10) 1-0-1 (1) 1-1-1 (2) SM OH SP- SM SP SM ML SM 1.5 5.0 7.0 12.5 20.0 22.5 32.5 Recycled Concrete (SM) Gray/brown fine silty sand (loose, moist) (Alluvium) (OH) Gray/brown organic silt (very soft, wet) (Alluvium) (SP-SM) Dark gray fine sand with silt and interbeds of silty sand (medium dense, wet) (Alluvium) (SP) Dark gray fine to medium sand (medium dense, wet) (Alluvium) (SM) Gray fine silty sand (medium dense, wet) (Alluvium) (ML) Gray silt (very soft, wet) (Alluvium) With shell debris (SM) Gray fine silty sand with shell debris (medium dense, wet) (Alluvium) NOTES LOGGED BY ZLL DRILLING METHOD Truck Mounted Drill Rig DRILLING CONTRACTOR Holocene GROUND WATER LEVELS: CHECKED BY JEB DATE STARTED 3/16/18 COMPLETED 3/16/18 AT TIME OF DRILLING 17.50 ft AT END OF DRILLING --- AFTER DRILLING --- HOLE SIZE 4.25" HSAGROUND ELEVATION SAMPLE TYPENUMBERDEPTH(ft)0 5 10 15 20 25 30 35 (Continued Next Page) PAGE 1 OF 2 Figure A-3 BORING NUMBER B-2 CLIENT HHJ Architects, PLLC PROJECT NUMBER P1238-T18 PROJECT NAME Walker Renton Auto Dealership Geotech Report PROJECT LOCATION 3400 East Valley Road, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 4/5/18 15:42 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1238-T18\P1238-T18 BORING LOGS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 RECOVERY (in)(RQD)BLOWCOUNTS(N VALUE)U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION SS S-9 SS S-10 SS S-11 SS S-12 18 18 18 18 3-4-6 (10) 3-5-3 (8) 4-5-5 (10) 7-9-9 (18) SM SM 40.0 51.5 (SM) Gray fine silty sand with shell debris (medium dense, wet) (Alluvium) (continued) (SM) Gray fine silty sand (loose, wet) (Alluvium) Grades to medium dense Bottom of borehole at 51.5 feet.SAMPLE TYPENUMBERDEPTH(ft)35 40 45 50 PAGE 2 OF 2 Figure A-3 BORING NUMBER B-2 CLIENT HHJ Architects, PLLC PROJECT NUMBER P1238-T18 PROJECT NAME Walker Renton Auto Dealership Geotech Report PROJECT LOCATION 3400 East Valley Road, Renton, WA COPY OF GENERAL BH / TP LOGS - FIGURE.GDT - 4/5/18 15:42 - C:\USERS\JESSICA\DESKTOP\TEST PITS AND BORINGS - GINT\P1238-T18\P1238-T18 BORING LOGS.GPJMigizi Group, Inc. PO Box 44840 Tacoma, WA 98448 Telephone: 253-537-9400 Fax: 253-537-9401 RECOVERY (in)(RQD)BLOWCOUNTS(N VALUE)U.S.C.S.GRAPHICLOGMATERIAL DESCRIPTION ESC Plan for Construction Stormwater Pollution Prevention Walker Auto Dealership 2180100.10 Appendix E Sediment Pond Sizing Project Wt4.11.C.O. P.VTo subiect—tp. SSZIK) With/To Project No r sl(60 \CO - Phone Fax # 1=I Page of E Calculations O Fax O Memorandum O Meeting Minutes Telephone Memo Address # Faxed Pages Date ciiit./1 By NkTrt tkt,,DL Le'StAE ST-5P, Civil Engineers Structural Engineers Landscape Architects Community Planners Land Surveyors eAs-T-t.) e BoiTowN hcS 1205-CD X LA-51-&-) kVA )(12. F_/o._) -z 20SO X 0.S57S- ' 17£54-1 BN5t.$) To ac5TitiA Q.1-7cCiri 6.cLLIcitt '10%-0 1.06..) yo. riztu 20S() X 1.557cl0-11‹ S If this does not meet with your understanding, please contact us in writing within seven days. THANK YOU. T 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 0+00 1+00 2+00 3+00 4+00 5+00 6+00 6+50 A C2.2 B C2.2 C C2.2 0+001+002+003+004+005+005+250+001+002+003+004+005+005+250+001+002+003+004+005+005+25D C2.3 E C2.3 F C2.3 FUTURE BUILDING PAD SUBGRADE ELEV: 21.25 SR 167SW 34TH ST EAST VALLEY ROADFS: 18.07FS: 17.67FS: 13.71FS: 13.71FS: 18.03FS: 20.55FS: 20.48FS: 20.51FS: 20.55FS: 20.09FS: 19.34FS: 20.60FS: 20.56FS: 20.48FS: 20.39FS: 20.30FS: 20.17FS: 18.75FS: 18.66FS: 18.14FS: 17.52FS: 13.71FS: 13.71FS: 18.19FS: 20.57FS: 20.42FS: 20.08FS: 20.39FS: 20.21FS: 19.94FS: 20.51FS: 20.59FS: 20.54FS: 20.48FS: 20.43FS: 20.24FS: 19.67FS: 19.68FS: 18.69FS: 17.36FS: 13.71FS: 13.71FS: 18.34FS: 20.57FS: 20.55FS: 20.55FS: 20.55FS: 20.55FS: 20.64FS: 20.68FS: 20.69FS: 20.60FS: 20.56FS: 20.57FS: 20.54FS: 20.58FS: 20.57FS: 19.16FS: 17.21FS: 13.71FS: 13.71FS: 18.50FS: 20.47FS: 21.10FS: 20.94FS: 20.89FS: 20.88FS: 20.92FS: 20.57FS: 20.37FS: 20.22FS: 20.19FS: 20.14FS: 20.13FS: 19.57FS: 17.06FS: 13.71FS: 13.71FS: 18.65FS: 20.61FS: 21.17FS: 20.50FS: 20.32FS: 20.12FS: 19.90FS: 19.69FS: 19.82FS: 19.57FS: 16.91FS: 13.71FS: 13.71FS: 18.80FS: 20.74FS: 21.19FS: 20.28FS: 20.08FS: 19.87FS: 19.85FS: 19.91FS: 19.75FS: 16.75FS: 13.71FS: 13.71FS: 18.95FS: 20.99FS: 21.23FS: 20.26FS: 20.27FS: 20.29FS: 20.30FS: 20.31FS: 20.09FS: 16.60FS: 13.71FS: 13.71FS: 19.11FS: 21.25FS: 21.25FS: 20.48FS: 20.46FS: 20.45FS: 20.43FS: 20.42FS: 20.54FS: 16.45FS: 13.71FS: 13.71FS: 19.26FS: 21.25FS: 21.25FS: 20.29FS: 20.09FS: 19.96FS: 19.95FS: 19.95FS: 20.56FS: 20.06FS: 19.89FS: 19.78FS: 20.38FS: 21.25FS: 21.25FS: 20.33FS: 20.14FS: 19.93FS: 19.72FS: 19.83FS: 20.41FS: 19.99FS: 19.75FS: 19.65FS: 20.37FS: 20.39FS: 20.27FS: 20.22FS: 20.18FS: 20.14FS: 19.95FS: 20.16FS: 19.75FS: 19.44FS: 20.51FS: 20.45FS: 20.49FS: 20.52FS: 20.56FS: 20.58FS: 19.92FS: 20.42FS: 20.27FS: 20.31FS: 20.70FS: 20.59FS: 20.37FS: 20.17FS: 20.20FS: 20.22FS: 20.00FS: 21.05FS: 21.04FS: 21.06FS: 21.17FS: 21.19FS: 20.75FS: 20.55FS: 20.28FS: 20.01FS: 20.17FS: 19.91FS: 20.80FS: 20.80FS: 20.83FS: 20.95FS: 21.12FS: 21.12FS: 21.09FS: 21.10FS: 21.11FS: 21.11FS: 21.10FS: 21.08FS: 21.05FS: 20.96FS: 20.75FS: 20.58FS: 20.41FS: 20.29FS: 19.44FS: 20.53FS: 20.54FS: 20.58FS: 20.68FS: 20.78FS: 20.79FS: 20.80FS: 20.81FS: 20.83FS: 20.85FS: 20.87FS: 20.89FS: 20.90FS: 20.92FS: 20.94FS: 20.96FS: 20.92FS: 20.79FS: 20.44FS: 20.28FS: 20.31FS: 20.37FS: 20.42FS: 20.46FS: 20.48FS: 20.50FS: 20.53FS: 20.56FS: 20.58FS: 20.61FS: 20.63FS: 20.66FS: 20.68FS: 20.71FS: 20.73FS: 20.79FS: 19.25FS: 20.19FS: 20.27FS: 20.30FS: 20.33FS: 20.36FS: 20.39FS: 20.42FS: 20.45FS: 20.47FS: 20.62FS: 19.25FS: 19.67FS: 20.46FUTURE BUILDING OUTLINE FUTURE EDGE OF PAVING (TYP.)FS: 18.96FS: 18.48FS: 21.06FS: 20.86FS: 20.74FS: 20.73FS: 20.82FS: 20.54FS: 19.58FS: 18.37FS: 20.65FS: 20.51FS: 20.39FS: 20.39FS: 20.58FS: 20.71FS: 20.54FS: 20.46FS: 20.54FS: 20.47FS: 20.38FS: 20.23FS: 20.15FS: 20.04FS: 20.10FS: 18.12FS: 18.94FS: 20.10FS: 19.80FS: 20.11FS: 20.22FS: 20.40FS: 20.33FS: 20.36FS: 20.03FS: 19.98FS: 19.95FS: 19.81FS: 19.61FS: 19.53FS: 19.37FS: 19.39FS: 19.37FS: 18.80FS: 19.43FS: 19.57FS: 19.16FS: 19.49FS: 19.20FS: 19.20FS: 18.95FS: 18.96FS: 19.01FS: 18.97FS: 18.40FS: 18.12FS: 17.62STRIPPED GRADE CONTOUR FINAL SUBGRADE CONTOUR TEMPORARY STORM PIPE 40 LF 12" CPEP @ 1.0% SEDIMENT TRAP RISER 12" CPEP SW=14.0 TEMPORARY SEDIMENT TRAP MIN. SURFACE AREA:1800 SF BERM ELEV: 19.0 WS ELEV: 18.0 BOTTOM ELEV: 14.5 BERM ELEV: 19.0 BOTTOM ELEV: 14.5 RR RR SPILLWAY ELEV: 18.0 SF MAINTAIN CONSTRUCTION ENTERANCE (TYP) HIGH POINTFS: 21.03FS: 21.05FS: 21.09FS: 20.47FS: 21.10FS: 20.46FS: 21.11FS: 20.50FS: 21.11FS: 20.47FS: 21.11FS: 20.50FS: 21.16FS: 20.56FS: 21.12FS: 21.10FS: 21.18FS: 20.65FS: 21.02FS: 20.90TEMPORARY SEDIMENT TRAP MIN. SURFACE AREA:1900 SF BERM ELEV: 16.5 WS ELEV: 15.5 BOTTOM ELEV: 12.0 BERM ELEV: 16.5 BOTTOM ELEV: 12.0 REFER TO LANDSCAPE PLANS FOR BUFFER RESTORATION2020202121 21 20 21212 1 20201920 2019CONTRACTOR TO PROTECT EXISTING BUILDING AND STORM DRAIN SYSTEM. EXCAVATIONS SHALL NOT ENTER ZONE OF INFLUENCE OF BUILDING FOUNDATION. OUTER SILT FENCE CAN BE REMOVED WHEN BUFFER IS STABILIZED N GRAPHIC SCALE 0 30 60 1" = 30 FEET 15 EARTHWORK VOLUMES ANTICIPATED CONTAMINATED SOIL REMOVAL (ASSUMING 1' DEPTH OF REMOVAL): 9,100 CY CUT:7,000 CY FILL:19,800 CY NET:12,800 (IMPORT) NOTE: VOLUMES ARE STRIPPED GRADE TO FINAL SUBGRADE. THE ABOVE QUANTITIES ARE ESTIMATES ONLY INTENDED FOR THE PERMITTING PROCESS. DO NOT USE FOR BID PURPOSES. THE QUANTITIES DO NOT HAVE STRIPPING, COMPACTION, OR CUT OR FILL ADJUSTMENT FACTORS APPLIED TO THEM. CITY OF RENTON IN COMPLIANCE WITH CITY OF RENTON STANDARDS Civil Engineers Structural Engineers Landscape Architects Community Planners Natural Resource Ecologists Land Surveyors Neighbors T A C O M A 2215 North 30th Street, Suite 300 Tacoma, WA 98403 253.383.2422TEL 253.383.2572FAX www.ahbl.comWEB S E A T T L E S P O K A N E T R I - C I T I E S WALKER AUTO DEALERSHIP EARLY CLEAR AND GRADE PLANS AHBL JOB #2180100.10 9 Know what's below. before you dig.Call RTED-40-4018C:18004244LUA:18-000305PR:18000212R-40180 ROUGH GRADING AND TESC PLAN C2.1 5 STABILIZE ALL DISTURBED AREAS WITH ROCK SURFACING AND STRAW Q:\2018\2180100\10_CIV\CAD\_Fill and Grade\2180100-SH-GRAD.dwgEATHWORK LEGEND FS = FINAL SUBGRADE FINAL SUBGRADE CONTOUR STRIPPED SURFACE CONTOUR NOTE: FINAL SUBGRADE SHALL BE UNDERLAIN BY 2.0' OF STRUCTURAL FILL IN BUILDING AND PAVED AREAS PER GEOTECHNICAL ENGINEER'S RECOMMENDATION. ELEV ELEV 75.00' WETLAND BUFFER TESC LEGEND RIPRAP ROCKERY 6"-8" QUARRY SPALLS GRAVEL CHECK DAM INTERCEPTOR DITCH @ 0.3% MINIMUM INLET PROTECTION SILT FENCE CLEARING LIMITS SEDIMENT TRAP RISER CONSTRUCTION ENTRANCE CL SF IP ID CD RR CE CE CE SF ID ID ID SF SF SF SF 5