Downramping to Minimize Stranding of Salmonid Fry

by Forrest W. Olson, CH2M Hill, Bellevue, WA, USA,
Roy G. Metzgar, CH2M Hill, Bellevue, WA, USA,

Document Type: Proceeding Paper

Part of: Water Power '87


The objective of this study was to develop a downramping regime for the Jackson Hydroelectric Project on the Sultan River in Washington that minimizes the stranding of juvenile salmon and steelhead while providing flexibility for power production benefits. The results of this study indicate that a downramping rate of 6 in/hr measured at the powerhouse tailwater, as initially stipulated in the project license, would be acceptable under some conditions but would cause excessive stranding of salmonid fry under other conditions. Susceptibility to stranding was particularly evident for salmon fry less than 50 mm long and for steelhead fry less than 40 mm long. On the basis of these findings a downramping regime was developed with rates ranging from 1 in/hr to 6 in/hr depending on season, river stage, and time of day. The study results strongly indicate the need to evaluate fry stranding potential on a river-by-river basis to account for differences in channel morphology, fish species, fry emergence time, and fish growth.

Subject Headings: Steel | Rivers and streams | Hydro power | Fish management | River and stream beds | Tailwater | Licensure and certification | Seasonal variations | Washington | United States

Services: Buy this book/Buy this article


Return to search