Publication Summary

A study of the Green River was conducted using the Instream Flow Incremental Methodology. This study provides fish habitat versus flow relationships for use in streamflow management by Ecology.

A study of the Green River was conducted using the Instream Flow Incremental Methodology. This study provides fish habitat versus flow relationships for use in streamflow management by Ecology. In addition, the study can be used by the Corps of Engineers to examine the downstream effects on fish habitat from increasing water storage behind Howard A. Hanson Dam and the present management of existing storage.

Five study sites, involving a total of 31 transects, represent fish habitat in 40 miles of the Green River. Fish habitat is defined in this study as water depth, velocity, substrate, and cover. Habitat measurements for the computer models were collected at three different flows. The five site models indicate peak habitat for spawning steelhead at flows ranging from 550 to 700 cfs, spawning chinook 525 to 700 cfs, spawning coho 240 to 375 cfs, spawning chum 260 to 400 cfs, juvenile steelhead 300 to 400 cfs, juvenile chinook and coho 140 to 240 cfs, adult holding chinook 220 to 450 cfs, and adult holding steelhead 300 to 600 cfs.