Mill Creek Fish Passage Project

After several years of planning and preparation, and eight weeks of construction, a new culvert has re-connected Mill Creek in eastern Skamania County for struggling wild fish populations. The culvert was located under Lakeview Road, about a mile south of Northwestern Lake Park.  Mill Creek flows into the White Salmon River about five hundred yards downstream of the culvert.

Called an open-bottom box culvert, the new 19.9-foot-wide structure is built with large precast cement blocks like enormous Legos, and functions similar to a low, wide bridge. It was designed by Tenneson Engineering Corporation of The Dalles, in partnership with Interfluve, Inc., of Hood River, and constructed by James Dean Construction of White Salmon in the summer of 2016.  In addition to opening fish passage, the new larger structure is designed to pass stream-flow during a 100-year flood, as well as any sediment or debris that might wash down.

The new structure replaces a four-foot-diameter corrugated steel pipe. Many undersized culverts, over time, scour plunge pools and erode streambeds, creating essentially steep manmade waterfalls. This hinders fish from swimming upstream and downstream, hampering or even cutting off fish-passage for returning steelhead and salmon species, and disconnecting fish populations.

UCD staff conducted a basin-wide fish passage inventory in 2009-2010, and the Mill Creek barrier under Lakeview Road ranked out as the highest-priority barrier to address, because of the length and quality of fish habitat upstream of the barrier as well as the significance of fish species accessing the creek.

Potential fish species benefiting from increased access to Mill Creek habitat include spring Chinook, Coho, summer and winter steelhead, Pacific lamprey, rainbow trout and possibly coastal cutthroat trout. Already, adult steelhead have been seen spawning in Mill Creek below the old culvert.  Now adult and juvenile salmon and steelhead will have greatly improved passage into Mill Creek, opening up several miles of high-quality rearing habitat.  Mill Creek maintains year-round flow and perennial pool habitat, which is increasingly important for fish survival during dry summer months.

UCD  secured funding for this project from several sources, including the Washington State Salmon Recovery Funding Board, the US Fish and Wildlife Service, the Pacific Coastal Salmon Recovery Fund via Yakama Nation Fisheries, and the Clark-Skamania Flyfishers club.  Salmon Recovery Funding in the White Salmon River watershed is administered by Klickitat County’s Department of Natural Resources and local technical and citizen-review  volunteers.

View a time-lapse video of the culvert construction: