Assessing effects of Columbia River Basin anadromous fish flow management on the aquatic ecology of the Henrys Fork watershed A Proposal By The Henrys Fork Foundation January 23, 2002

1.7 mil acres in size 235K acres of irrigated farmland 56 % public land 40K people mile of rivers, streams and canals

The Henrys Fork is a regulated hydrologic system that provides water for irrigation, hydroelectricity, recreation, and flow augmentation for salmon

Providing water for multiple uses under different weather patterns results in a variety of stream flow and reservoir conditions

What happens to fish populations under various flow regimes and habitat conditions?

HFF, IDFG, and ISU fisheries research on the Henrys Fork has focused primarily on juvenile trout survival and dispersal

Data on relationship between late- winter discharge at IP Dam and juvenile trout abundance

Project Goal: Assess the correlation between stream flows and fish populations, and identify critical thresholds

Project Objectives Estimate spring and fall trout population size Estimate annual winter survival and dispersal Estimate egg to fry survival in Henrys Lake Outlet Estimate upstream migration into Buffalo River Estimate habitat availability across flow regimes Continue Long-term Synoptic Habitat Monitoring Correlate above estimates with flow management data

How will the information learned from this project be used? Guide future discussions on instream flows for fish and wildlife Inform water management decisions Inside the box... Outside the box….