ENUMCLAW – In late February, contractor crews working for the Washington State Department of Transportation will begin repairs to increase stream capacity at Dry Creek at its intersection with State Route 410. This work will add temporary measures to upgrade an existing 24-inch culvert under SR 410 a few miles below Crystal Mountain Ski Resort (milepost 55.2).
Heavy rains in early November created a debris flow along Dry Creek above SR 410 and completely blocked the ironically named creek’s channel, forcing it to flow into another channel with a smaller culvert under SR 410. The smaller culvert plugged, causing water and two feet of debris to spill across SR 410. The highway reopened after several hours, once WSDOT cleared and inspected it.
Dry Creek’s course change is permanent, and repairs to expand flow capacity under SR 410 are needed to avoid similar or worse damage to the highway in the future. WSDOT will divide the project into two phases to lessen the affect to businesses, residents and services located above Dry Creek.
During the first phase of repairs in late February, travelers can expect SR 410 to be reduced to a single lane at Dry Creek, with flaggers alternating traffic. Crews will insert three 24-inch overflow culverts a few feet beneath the roadway, effectively diverting Dry Creek’s excess runoff.
The second phase of the project later this year requires a full closure of SR 410 for several days so crews can excavate a 100-foot section of the highway, place a new 10-foot culvert and rebuild the highway. The overflow culverts installed in February will mitigate the risk to the highway during spring runoff and allow WSDOT to delay the full closure until after peak ski season.