King County: Oops, we made a sinkhole
KENMORE, Wash. -- A public construction project with a troubled past has a gaping new problem to deal with.
King County's Brightwater Sewage Treatment System project is being blamed for a large sinkhole on the Eastside.
The hole is some 15 feet deep and falls at the foot of a private driveway. And the county admits, yes, Brightwater is to blame.
King County said the work crews were performing some 150 feet below the surface caused the ground to sink away on Sunday.
At the Brightwater construction site in Kenmore, two underground tunnels are being built here to carry sewage to and from the new treatment plant. Inside each tunnel is a mammoth boring machine that cuts through rock, sand, gravel -- whatever it encounters.
Crews have been working since Sunday to fill the sinkhole.
But the Kenmore site has had a number of problems.
A KOMO News investigation last year uncovered evidence of construction spills at one part of the county's project, and prompted the state Department of Ecology to launch its own investigation of the $2 billion project.
Last July a waste tank overflowed, spilling a muddy mix everywhere. One of the boring machines had hit sand, causing compressed air to explode up through the surface and sending a muddy soup downstream into the Sammamish Slough.
The tanks, which contain a variety of waste and chemicals called "slurry," overflowed at least three times, and the state issued the county a notice of violation.
The county's construction manager for the tunneling projects said this time, the boring machine likely excavated too much ground, creating an air pocket that worked its way up to the surface.
King County's Brightwater Sewage Treatment System project is being blamed for a large sinkhole on the Eastside.
The hole is some 15 feet deep and falls at the foot of a private driveway. And the county admits, yes, Brightwater is to blame.
King County said the work crews were performing some 150 feet below the surface caused the ground to sink away on Sunday.
At the Brightwater construction site in Kenmore, two underground tunnels are being built here to carry sewage to and from the new treatment plant. Inside each tunnel is a mammoth boring machine that cuts through rock, sand, gravel -- whatever it encounters.
Crews have been working since Sunday to fill the sinkhole.
But the Kenmore site has had a number of problems.
A KOMO News investigation last year uncovered evidence of construction spills at one part of the county's project, and prompted the state Department of Ecology to launch its own investigation of the $2 billion project.
Last July a waste tank overflowed, spilling a muddy mix everywhere. One of the boring machines had hit sand, causing compressed air to explode up through the surface and sending a muddy soup downstream into the Sammamish Slough.
The tanks, which contain a variety of waste and chemicals called "slurry," overflowed at least three times, and the state issued the county a notice of violation.
The county's construction manager for the tunneling projects said this time, the boring machine likely excavated too much ground, creating an air pocket that worked its way up to the surface.