Bank stabilization work nearly complete on Cosi Hill

Second slide repair 1,000 feet up the hill still in design phase

By Dan Hammock • June 9, 2020 3:30 pm
COURTESY DEPARTMENT OF TRANSPORTATION New pavement on Highway 101 at Cosi Hill. The roadway was closed for five days as the roadway was paved, one of the last steps in the $10 million project to shore up a slide-prone section of roadway near milepost 79.
COURTESY DEPARTMENT OF TRANSPORTATION New pavement on Highway 101 at Cosi Hill. The roadway was closed for five days as the roadway was paved, one of the last steps in the $10 million project to shore up a slide-prone section of roadway near milepost 79.

After months of construction and the installation of 576 6-foot, rock-filled shafts, the Highway 101 bank stabilization project near milepost 79 on Cosi Hill is nearly complete.

“Barrier work and final striping are the last major activities to complete Cosi Hill (in the first slide zone),” said Department of Transportation Olympic Region spokeswoman Tina Werner. “We are hopeful this work will wrap up by summer.”

The roadway was closed June 1 through 5 as pavement was laid on the three lanes through the project area. Those lanes reopened Friday. Drivers can still expect occasional lane closures as the barrier and striping continues for the next month or so.

The $10 million project is a more permanent solution to the slides that closed the roadway over the years. The 576 shafts — 3.7 miles worth — were drilled 20-50 feet deep and filled with nearly 29,000 tons of rock to stabilize the bank below the roadway.

Just up the hill about 1,000 feet, stop signs remain in place at a second slide, this one occurring in late January. There, a significant slide ate away at the roadway, and a fix is still in the works.

“It is currently in the design process and we anticipate advertising the project this fall, with construction occurring this winter,” said Werner.