Assessing effects of Columbia River Basin anadromous fish flow management on the aquatic

ecology of the Henry’s Fork watershed

A Proposal By

The Henry’s Fork Foundation January 23, 2002

1.7 mil acres in size

235K acres of

irrigated farmland

56 % public land

40K people

3000+ mile of rivers,

streams and canals

The Henry’s 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 Henry’s Fork has focused primarily on juvenile trout survival and dispersal

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

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R2 = 0.9731

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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 Henry’s 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….