Mcnary Prototype Fishway Entrance Structure for Enhanced Lamprey Attraction and Passage

Fishways at mainstem dams on the lower Snake and Columbia rivers are optimized primarily for attraction and upstream passage of several species of salmon and steelhead, but other species also use them, including shad, lamprey, bull trout and other resident species.  Fishway entrances optimized for salmonid passage do not necessarily provide optimum attraction and passage conditions for lamprey, and may actually act as obstacles or barriers. 

The U.S. Army Corps of Engineers, Walla Walla District developed and deployed a prototype entrance structure at an entrance to the adult fishway at McNary Lock & Dam on the Columbia River to enhance lamprey passage.  A 1:9 physical hydraulic model constructed at the Engineering Research and Development Center in Vicksburg, MS was used extensively during design development to ensure the prototype structure would meet lamprey passage criteria while maintaining good fishway entrance conditions for salmonids. 

This presentation will describe the development of lamprey passage criteria for the fishway entrance with close collaboration with federal, state, and tribal fishery agencies in the region, and the design process for the prototype entrance to apply those criteria, especially the physical hydraulic modeling.  A companion presentation will describe the biological testing of the prototype structure.