Idaho Water Rental Pilot Project Probability/Coordination study resident fish andwildlife impacts, Phase III, Annual Report

摘要

Phase III began in 1995 with the overall goal of quantifying changes in residentfish habitat in the Snake River Basin upstream of Brownlee Reservoir resulting from the release of salmon flow augmentation water. Existing data, in the form of weighted usable area versus flow relationships, were used to estimate habitat changes for white sturgeon (Acipenser transmontanus) and rainbow trout (Oncorhynchus mykiss) in the Snake River between C.J. Strike Dam and Brownlee Reservoir in 1998. Existing data was also used to estimate habitat changes for rainbow trout and bull trout (Salvelinus confluentus) in the Deadwood River between Deadwood Dam and the mouth from 1994 to 1998. The increased flows resulted in an increase in the quantity of useable habitat for adult and juvenile white sturgeon and adult rainbow trout and decreases in the quantity of rainbow trout fry and juvenile habitat in the Snake River. Flows in the Snake River have rarely met mean monthly flow recommendations for the past five years despite the addition of the flow augmentation releases. It is unlikely that the flow augmentation releases have had any significant long-term benefit for sturgeon and rainbow trout in the Snake River.