Department of Ecology News Release - June 18, 2015
SKYKOMISH – The final phase of one of Washington’s most complex environmental cleanup projects – one that included moving a score of buildings – is beginning in Skykomish, now that school is out for the summer.
Contractors for BNSF Railway, working under Washington Department of Ecology oversight, will install equipment to remove petroleum contamination under the town’s school building.
A railway maintenance and fueling facility operated in Skykomish – a small town located off Highway 2 near Stevens Pass – from the early 20th century until 1974. Over the decades, bunker-C heavy fuel oil and diesel fuel were discharged at the rail yard. The oil then flowed downward to the water table and under the town to the South Fork of the Skykomish River. The multi-year cleanup has removed oil from underneath Skykomish, and heavy metals contamination in certain areas.
The town’s Depression-era reinforced concrete school building posed the most daunting technical challenge because the building was too large to lift and replace for cleanup. Ecology, the Skykomish School District and BNSF have agreed on a three-part approach:
Hot water flushing: Contractors will install a 30-foot-deep underground steel sheet pile wall around the school property. Twenty-five injection wells and 10 extraction wells will “flush” hot water through the soil and pump out contaminated water. The removed water will be treated and then re-injected into the system. Hot flushing will occur only in the summer, with cold water treatment in use during the school year.
Soil vapor extraction: Vapor from oil contamination can gather in spaces between rocks and soil particles. Six soil-vapor extraction wells and nine air-inlet wells will remove the soil vapor and clean it with a carbon filter system.
Safety and monitoring: A geomembrane liner will cover the entire treatment area to contain soil vapors and keep out stormwater. Monitoring equipment in the building and outside will keep track of temperatures, pressures, and air quality.
The cleanup process will take several years to complete, but the school will be able to operate normally during the process.
From 2006 to 2011, cleanup crews removed and replaced 21 buildings, 1,200 feet of river levee, the main road embankment into town, and two wetlands. Contractors hauled away approximately 350,000 tons of contaminated soil, and delivered a like amount of clean fill. They also removed approximately 218,000 gallons of oil and treated approximately 20 million gallons of contaminated groundwater.
Before the cleanup, Ecology funded a town planning process to map out community ideas and plans for its post-cleanup development. Ecology also provided grants for a town wastewater system, installed in conjunction with cleanup excavations.
Some preparation has begun at a staging area near the school. Construction of the system at the school building is set to start next week end prior to Aug. 21. The last day of classes was June 17.
Larry Altose, Ecology communications, 425-649-7009, @EcySeattle
Brad Petrovich, Ecology community outreach, 425-533-5537
Martin Schmidt, Skykomish School District Superintendent, 360-677-2623
Gus Melonas, BNSF Railway, 206-625-6220
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