Migration behavior of juvenile salmonids and evaluation of a modified flume entrance at Cowitz Falls Dam, Washington, 2001

Historically, the Cowlitz River watershed supported abundant runs of anadromous salmonids. The completion of the surface collection system and fish facility at the Cowlitz Falls Dam presented a unique opportunity to restore anadromous salmonids to the upper Cowlitz River watershed. Collecting smolts at Cowlitz Falls Dam, or before they enter the main body of Riffe Lake, is the key to restoring anadromous fish populations because Mossyrock Dam lacks fish passage facilities. However, after the first two seasons of operation, estimates of fish collection efficiencies (FCEs) based on mark recaptures have been as low as 5% for coho salmon smolts, and at times, up to 76% for steelhead smolts.