Loading...
HomeMy WebLinkAboutCM_Construction_Mitigation_Plan_180713_v1.pdfCONSTRUCTION MITIGATION PLAN Sam’s Club UST Removal Project Russell Morgan 901 South Grady Way NRC Project Manager Renton, WA Phone: 503.849.0753 Email: rmorgan@nrcc.com Description of Proposed Work The Sam’s Club UST removal project site is located in the southwest section of the parking lot of the former Sam’s Club located at 901 South Grady Way, Renton, WA. The facility was previously operated as a retail fueling station selling gasoline to the public (Sam’s Club Members). The fueling facility and store have been closed for business. The underground storage tanks were “pumped down” to approximately one (1) inch of residual gasoline product remaining in the bottom of the tanks. The tanks have remained “out of service” with the decommissioning and subsequent removal of the three (3) 20,000-gallon gasoline USTs as the primary focus of this project. The project will also include the dismantling/demolition of the rain canopy that “covers’ the pump islands (~40’x80”) and the demolition of the attendant kiosk building (~15’x30`). Current tentative start date of Tuesday July 31, 2018 with completion in 10 – 12 workings day (~August 16, 2018) with onsite operating hours of approximately 07:00 AM to 4:00 PM Monday through Friday (see “Noise” section for additional details). General Site Soil/Conditions The site is generally flat and is “covered” by asphalt paving with some areas of concrete paving (islands and tank pad). The underlying soils appear to be a glacial till with occasional lenses of other types of soil including but not limited to sand, gravel, clay and silt. Store management has indicated that there have been no known reportable spills at the fueling facility. Stormwater Runoff Since the project site is an existing site parking lot, stormwater runoff will be collected by a series of existing catch basins and pipes. The existing parking lot is sloped in a manner to direct stormwater flow to these catch basins. The catch basin will be fitted with catch basin filter socks designed for the existing catch basins. The catch basins discharge to the City of Renton’s stormwater sewer system. NRC will also install contractors boom on the down gradient side of the work zone as an additional contingency to eliminate or minimize materials from migrating to the catch basins and their filter socks. This boom will be held in placed by strategically placed sand bags. Soil Disturbance The project will require the demolition and removal of a concrete tank pad located immediately above the tanks. The concrete will be demolished utilizing a hydraulic breaker attachment on an excavator. Dust generated by the demolition process will be mitigated by the application of water spray to suppress the migration of any dust. Periodic dust monitoring will be performed in the general work area to delineate and document the amount of particulate being produced. Although OSHA permits 5 parts per million (ppm), it is NRC’s company policy to maintain dust levels at or below 3 parts per million (ppm) above existing background levels. NRC’s dust suppressing technique utilizes minimum amounts of water so typically there is no surface runoff of concern during the process. The soil (pea gravel bedding) around the USTs is the only “soil” currently identified for removal. The pea gravel (~100 cubic yards) will be removed from the interstitial space between the top of the UST and the bottom of the concrete tank pad. This space is estimated to be one (1) to two (2) feet in thickness and comprised of pea gravel tank bedding material. The pea gravel will be placed on a bermed plastic liner for sampling and analysis by the engineer’s (Terracon Consultants) site assessor. The stockpile pea gravel will be covered with plastic sheeting pending the results of the testing. If the pea gravel is unsuitable as backfill material, the gravel will be hauled offsite for disposal at a licensed landfill or transfer facility. A total of approximately 700 tons of material will be required to backfill the excavation. This material will include any approved pea gravel, asphalt subbase (~6), asphalt paving (~4”) and any remaining amount of the 700 tons will be imported general backfill material purchase from a local quarry, sand and gravel pit or other commercial provider of clean backfill. Air Quality Demolition and UST removal would result in a temporary increase in air pollution, including emissions from equipment and minimal dust from work activities. As discussed above, dust emission will be monitored in the general work area to minimize or eliminate any exposure to the crew and the public at large. Periodic work zone air monitoring utilizing a PID will also be performed to protect workers and the public at large from elevated levels of VOCs. Similarly, standard work practices and action levels will be implemented during the removal of the USTs. The project is currently scheduled at approximately two weeks for completion. Post construction emissions would be non-existent since the facility is closed and barricaded to the public. Noise Demolition and UST removal would result in a temporary increase in noise. Temporary, short term noise impacts typical of construction type projects will occur during demolition and UST removal and will be limited in duration (approximately 2 weeks). The excavator “breaking” concrete will generate the most noise spanning an approximate three-day period. “Construction work activities will occur during daylight hours as outline in the City of Renton’s regulations governing construction projects. Work will typically start at 7:00 AM with a 15-30-minute safety meeting prior to starting work activities. No weekend work planned for this project. Long term noise will be nonexistent since the facility is closed and barricaded to the public. Traffic Demolition and UST removal would result in a temporary increase in traffic in the general vicinity of the site. Temporary, short term traffic impacts typical of construction type projects will occur during demolition and UST removal and will be limited in duration (approximately 2 weeks). The import of backfill material will impact area traffic the most with trucks entering and leaving the site. This “import truck” traffic is estimated to span an approximate three-day period. Construction traffic will occur during daylight hours as outline in the City of Renton’s regulations governing construction projects. It is anticipated that truck will operate from approximately 7:00 AM to 4:00 PM. Long term traffic should not be affected by the project. Vehicles exiting the site will turn left onto Talbot Road S traveling north bound approximately one block to the intersection of South Grady Way. Vehicles will turn left onto South Grady Way proceeding in a westerly direction to the intersection of Rainier Avenue South. Vehicles will turn left onto Rainier Avenue South and proceed in a southernly direction for approximately one block turning right onto Interstate 405 on ramp. Vehicles will continue Interstate 405, I-5 and other roads to their final destination. Proposed haul routes would be. Any vehicles exiting 405 south bound traveling north bound on Talbot Road will enter the property at the existing south west “ramp” entrance to the Sam’s Club located immediately adjacent to the work area. Vehicles approaching the site from 405 north bound at Rainier Avenue south exit will travel easterly along South Grady Way entering the site at the Sam’s Club north “ramp” entrance to the Sam’s Club. Energy Conservation There are no energy conservation features associated with this project since no construction is being performed. Trees There are no trees scheduled for removal at this time. There is one landscaped area adjacent to the Kiosk which may be impacted during removal operations but will be re-landscaped at the conclusion of the project.