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HomeMy WebLinkAboutCM_Construction_Mitigation_Description_180309_v1 King County South Plant Biogas and Heating System Improvements 1 ESA / D150513.00 CUP / Site Plan Review Submittal February 2018 Construction Mitigation Description Proposed construction dates (begin and end dates) Project construction is scheduled to occur from May 2019 to May 2021. Hours and days of operation Construction is expected to be limited to normal working hours (7:00 am to 5:00 pm) and weekdays (no weekend work or work on legal holidays). Proposed hauling/transportation routes Project construction will require approximately 750 truck trips over approximately two years in order to deliver materials including concrete, asphalt, and other building materials. Haul routes will be determined by the contractor. The construction contractor will be required to develop a detailed traffic control plan for review and approval by the City of Renton prior to commencing any work or traffic control within the City’s right-of-way, though not anticipated. These plans would be required to conform with all City of Renton requirements and would document the construction contractor’s proposed haul routes. Measures to be implemented to minimize dust, traffic and transportation impacts, erosion, mud, noise, and other noxious characteristics The construction contractor will be required to develop a detailed traffic control plan as well as an environmental mitigation plan prior to commencing the work on site. These plans will be required to conform with all City of Renton requirements and will document the construction contractor’s procedures for minimizing dust, traffic, erosion, noise, and other impacts resulting from construction traffic. Best Management Practices (BMPs) identified in the SEPA Checklist for the project are detailed below. Other BMPs may be identified by the contractor. BMPs to Minimize Dust Street sweeping, watering exposed soil surfaces, and covering soil stockpiles to help minimize the amount of fugitive dust and particulate pollution to the surrounding areas. BMPs to Minimize Traffic and Transportation impacts Truck trips will be substantially minimized by relocating spoils excavated as part of the project to another location on the South Treatment Plant (STP) site. Spoils excavated for construction of the Heat and Energy Recovery Building (HERB) will be placed on an approximately 1-acre area south of the digesters located within an open lawn area in the center of the STP site (and compacted and seeded to match existing grades and slopes). BMPs related to truck trips required for materials and equipment will be identified in the traffic control plan. Construction Mitigation Description King County South Plant Biogas and Heating System Improvements 2 ESA / D150513.00 CUP / Site Plan Review Submittal February 2018 BMPs to Minimize Erosion and Mud Temporary erosion and sedimentation control measures will be employed throughout project construction, including prior to all clearing, excavation, filling, grading, and other soil-disturbing activities in the project area. Typical measures include installing filter fabric fences and other sediment barriers, placing silt traps in storm drain inlets, covering soil stockpiles and exposed soils, and using settling facilities to prevent sediment from leaving the site. Spoils placed onsite will be compacted, seeded, and temporarily covered with plastic or blankets where needed in order to prevent erosion. Additional BMPs and other measures could include the following:  Designation of personnel to inspect and maintain temporary erosion and sediment control measures,  Use of appropriate means such as stabilized entrances and wheel washes to minimize tracking of sediment onto roadways by construction vehicles,  Regular street cleaning for mud and dust control,  Disposing of excess excavated soil at an approved disposal site as soon as practical, and;  Restoration of disturbed areas by repaving or replanting as soon as practical after construction is completed. BMPs to Minimize Noise Construction BMPs will be used to minimize construction noise and could include:  Using effective vehicle mufflers, engine intake silencers, and engine enclosures, and shutting off equipment when not in use;  Using temporary noise barriers around stationary equipment;  Positioning noise-generating equipment in the project area so that it is as far away as possible from sensitive receptors;  Notifying residents and businesses near the project site of upcoming noisy construction activities, and;  Use of a 24-hour construction hotline to promptly respond to questions and complaints. Other Applicable BMPs Construction equipment-related emissions will be reduced by requiring proper maintenance of equipment, using electrically-powered equipment where practical, and avoiding prolonged idling of vehicles and equipment. BMPs will be implemented during construction to minimize the potential for spills or mechanical failures to occur, and to minimize the potential for adverse effects from hazardous chemicals to workers or nearby residents. Construction Mitigation Description King County South Plant Biogas and Heating System Improvements 3 ESA / D150513.00 CUP Submittal February 2018 Any special hours proposed for construction or hauling (i.e. weekends, late nights) Construction is expected to be limited to normal working hours (7:00 am to 5:00 pm) and weekdays (no weekend work or late night work). Preliminary traffic control plan As described above, the construction contractor will be required to develop a detailed traffic control plan. Traffic control requirements are anticipated to be minimal; no lane closures or detours are anticipated.