Powder River Irrigation Diversions

Modernizing agricultural water infrastructure

About the Project

The Middle Fork of Powder River, a tributary of the Yellowstone River, flows from the Bighorn Mountains of north central Wyoming in an easterly direction toward the small town of Kaycee. Flowing mostly through private agricultural and ranching land, the Middle Fork is known as one of Wyoming’s most productive trout streams. The ten-mile stretch of the river through Middle Fork Canyon is accessible to the public and frequented by fishermen and recreationists.

This project will remove and replace three damaged irrigation diversion dams—the Gosney, Moffett, and Harlan dams—with natural-like cross-vane diversion structures, opening 33.1 stream miles on the Middle Fork. The three concrete diversions were built in the 1890’s and damaged in 2019 during a flood. The diversions are owned by local landowners who all support their removal and replacement.

The Powder River Conservation District coordinated the project, which demonstrates to local landowners the economic and environmental benefits of modernizing irrigation diversions. The project restores floodplain and stream connectivity, improves water quality, provides cold water habitat for fish in the summer, promotes sediment transport, and saves farmers time and money on their irrigation needs.

The removal and replacement of the three diversions reconnects the entire length of the Middle Fork from its confluence with the Powder River to Middle Fork Canyon. The next barrier of concern in the watershed is the Sahara Diversion on the Powder River, located just downstream of its confluence with the Middle Fork.

FACTS AT A GLANCE
Owner: Private landowners
Size: Gosney (35 feet wide by 3.2 feet high), Moffett (20 feet wide by 2.9 feet high), and Harlan (10 feet wide by 2.5 feet high)
Project Cost: $1.68 villion
ORF Investment: Construction
Miles Opened: 33.1 miles
Fish: Rainbow trout, brown trout, stonecat, flathead chub (Wyoming tier III species), and longnose sucker
Status: Three diversions removed in 2021


OUTCOMES
  • Open 33.1 miles of cool water habitat and spawning grounds in one one of Wyoming’s most productive trout streams
  • Restore floodplain and stream connectivity allowing for the flood waters that occur regularly to pass through with little issue and for fish to access seasonal spawning, winter holding, and summer thermal refuge habitats
  • Improve river habitat by reducing water temperatures during summer months, ensuring coverage for fish during low flows, and promoting sediment transport during high flows
  • Improve water quality by reducing bank erosion
  • Ensure the continuation of the region’s historic ranching community with updated diversion infrastructure
  • Build momentum with local landowners to remove/replace a final diversion on the Powder River, located just downstream of its confluence with the Middle Fork
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Project Partners

Private landowners

Powder River Conservation District

Trout Unlimited

Wyoming Game and Fish Department

Wyoming Wildlife and Natural Resource Trust

Wyoming Natural Resource Foundation

Town of Kaycee

Johnson County Commissioners

Powder Reservoir Corporation

U.S. Natural Resources Conservation Service

U.S. Fish and Wildlife Service