Koch Slough Weir Repair and Biological Monitoring

Cherokee Construction Services, LLC

Stillaguamish River, Washington

Koch Slough

Hart Crowser assessed migratory fish populations in a 5-kilometer dewatered stream channel during a US Army Corps of Engineers weir repair project.  We conducted weekly snorkeling surveys, and designed and implemented a turbidity and temperature monitoring program for compliance with Clean Water Act Section 404 permit conditions and to determine environmental conditions for trapped fish. We conducted fish salvage operations, conducted habitat and riparian (the area between land and water) surveys, and mapped habitat features.  Fish salvage operations were conducted using electrofishing and seines, removing and releasing unharmed over 95 percent of adult pink salmon and Chinook salmon, steelhead trout, and bull trout within the dewatered channel. Repairs have since been completed.