The Washington State Department of Transportation and its contractor, Flatiron West Inc., face a $22,000 joint fine from the state Department of Ecology for a series of spills into Lake Washington in Seattle along part of the State Route 520 Bridge construction project.
Ecology’s penalty cites nine releases between March 2015 and April 2016 on the West Approach Bridge North segment, between Montlake Boulevard and the new floating bridge. Eight involved drilling slurry and one was biodegradable hydraulic oil.
WSDOT reported the violations to Ecology. The spills ranged from one cup of hydraulic oil to approximately 5,000 to 8,000 gallons of slurry.
“Flatiron West failed to prevent and contain these spills,” said Gordon White, who manages Ecology’s Shorelands Program. “Communities around Lake Washington have spent millions and work hard every day to protect it for fish, swimming and recreation. This is why our permit requires the contactor to protect the water quality in Lake Washington by preventing such discharges."
Shafts drilled into lake bed
The incidents occurred where new elevated westbound lanes will rest on 99 columns, 89 of which are in the water. Flatiron West’s subcontractor, Malcolm Drilling, used more than 8 million gallons of slurry to install 8- to 10-foot diameter shafts to make concrete foundations for the columns. Some of the shafts are 100 or more feet deep.
Slurry is a thick fluid used in drilling. It congeals the soil being removed and stabilizes the drilled hole until concrete is placed in the shaft. After use, slurry is pre-treated before disposal into the sanitary sewer which flows to King County’s West Point treatment plant.
Spills entered Lake Washington
The spills released untreated slurry with a potential to harm aquatic life and degrade water quality.
The largest slurry spill occurred when a steel shaft casing shifted, allowing the water-soluble fluid to escape out the bottom of the casing. Other spills came while decoupling a hose, and from cracks in hoses or seal leaks at joints in steel shaft casings.
“WSDOT is committed to environmental stewardship on all our projects. We’re continually working to improve our construction practices and comply with environmental regulations,” said Julie Meredith, WSDOT Administrator for the SR 520 Bridge Replacement and HOV Program. “Whenever an environmental incident occurs, WSDOT and its contractors immediately evaluate the circumstances and stop work, if needed, to address the situation. Our contractor modified its procedures after each spill in an effort to prevent future incidents.”
“We share the Department of Ecology’s and WSDOT’s commitment to environmental stewardship,” said Jeff Turner, District Manager of Flatiron West. “We have reviewed the causes of these isolated incidents, and our people are working extremely hard to protect the environment and safely complete this project,”
Ecology’s penalties are subject to appeal within 30 days to the Washington State Pollution Control Hearings Board.