PROJECT OVERVIEW

The Big Wood River is home to many species of fish including the native redband trout, mountain whitefish, and the endemic Big Wood River sculpin. Each year, thousands of these fish are drawn into irrigation canals and ditches, unable to return to the river. These unintended losses reduce fish populations and disrupt the river’s natural balance.
 

The Fish Screen Project—led by Project Big Wood in partnership with Trout Unlimited Hemingway—is addressing this challenge head-on. By installing modern fish screens at key canal entrances, we can keep fish in the river where they belong, protect biodiversity, and improve water management for the benefit of both people and ecosystems.

 

PROJECT GOALS AND BENEFITS

• Support ecosystem health: Safeguard native fish populations and strengthen aquatic habitats.

• Restore river connectivity: Maintain natural migration routes between the Big Wood River, its tributaries, and Magic Reservoir.

• Advance stewardship: Demonstrate how science-based solutions can reduce impacts from human infrastructure while supporting long-term watershed resilience

• Protect river health: Prevent native fish from entering irrigation canals each year, keeping reproduction and rearing within the natural stream channel

• Strengthen native populations: Support Interior Redband Trout, Mountain Whitefish, and Big Wood River sculpin

• Balance river use: Demonstrate how irrigation infrastructure can coexist with healthy aquatic ecosystems

• Create a replicable model: Provide science-based guidance for future fish screen installations in other reaches of the watershed

Fish screens provide a proven way to reduce fish mortality, protect natural migration patterns, and restore connectivity between the Big Wood River and its tributaries. By beginning with a feasibility phase, Project Big Wood is laying the groundwork for a carefully planned, effective, and lasting solution that benefits both the river and the community.

 

PHASE ONE: FEASIBILITY STUDY AND FISH MOVEMENT ASSESSMENT

To build a solid foundation for this project, Phase One focuses on understanding the scope of the problem and identifying the best solutions for the Big Wood River. This work includes:

• Canal inventory: Mapping canal and ditch systems along the river to pinpoint where fish screens are most urgently needed.

• Fish movement study: Tracking fish populations and movements, including manual counts, to measure the scale of losses to irrigation systems.

• Screen design evaluation: Reviewing proven screen technologies, such as Farmers’ and Hendricks’ screens, to match solutions to site-specific conditions.

• Cost and priority analysis: Developing cost estimates and ranking diversion points by ecological importance, with particular attention to high-priority sites like Diversion 45, where roughly 20,000 fish are rescued each year.

 

PHASE TWO: FISH SCREEN INSTALLATION

Native trout and other aquatic species in the Big Wood River face ongoing losses to unprotected irrigation canals, where tens of thousands of fish are diverted each year. At Diversion 45 alone - the largest canal in Blaine County - roughly 20,000 fish are rescued annually. Without intervention, these diversions will continue to erode fish populations, reduce biodiversity, and compromise both ecological health and recreational opportunities that support the local economy.

Fish screens are a proven solution - keeping fish in the river, protecting water quality, and supporting irrigation operations. Phase Two will build on the feasibility study by:

• Survey site assessments of major canals and ditches, beginning with Diversion 45.

• Dry fit the electric screen to the chosen canal. 

• Install fish screens. 

• Monitor their effectiveness over time.
   

This work will directly benefit native species such as Interior Redband Trout, Mountain Whitefish, and Big Wood River sculpin by reducing losses, restoring natural migration pathways, and strengthening connectivity to Magic Reservoir. Initial efforts will focus on Diversion 45, followed by assessments of additional canals, including Cove, Hiawatha, Glendale, and McCoy Ditch. The long-term goal is a resilient river system where irrigation infrastructure and aquatic habitat coexist.

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PARTNERS

To complete this long anticipated project, Project Big Wood has partnered with Trout Unlimited Hemingway, IDWR District 37, and Idaho Fish and Game to implement fish screens at high priority canals in the Big Wood River.