WSDOT is in a heated battle with erosion along the Pilchuck River
Jul 12, 2016, 6:54 AM
The Washington State Department of Transportation is battling the mighty Pilchuck River in Snohomish County, and if it doesn’t do something soon, Granite Falls could be cut off.
Highway 92 is the main route between Lake Stevens and Granite Falls, but the Pilchuck River is doing what rivers do: moving and eroding the river banks.
Unfortunately for residents, it’s getting awfully close to undercutting the highway.
“If we were to just do nothing, we would lose the highway, more than likely, next year, and we just can’t allow that to happen,” said Kris Olsen with the Washington State Department of Transportation.
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The state began tracking the erosion in 2009. They have been losing the battle against the river ever since. A house has been lost to the river. Several sheds have also gone in.
The river is now inside 40 feet from undercutting the highway, but work is underway to get the erosion under control.
“We’re not going to move the river or move the channel,” Olsen said. “What we need to do is stop it from hitting that edge with such force and velocity.”
The fix: build an earthen berm to reinforce the bank.
“We embed big logs and rocks and debris and root wads in there,” Olsen explained.
Workers will be using what’s called an aqudam to create a work zone in the river. It’s a giant bladder that will be filled with water that will re-channel the river during construction.
“It will slowly push the Pilchuck River over to the side to give us a drier riverbed to work in,” Olsen explained.
This work should take a few months to complete. WSDOT also has some landscaping work to do above the river to prevent erosion from above.
Drivers will have to deal with a detour during construction. Westbound drivers coming out of Granite Falls will peel off at 84th Street Northeast to connect to Highway 9. Eastbound drivers will stay on Highway 92, but they will travel in the westbound lanes around the construction zone.
