The Central Bear River watershed in eastern Idaho and southwestern Wyoming supports one of the last robust population of fluvial (river-migratory) Bonneville cutthroat trout (BCT) and some of the only known populations of leatherside chub and bluehead sucker in the entire Bear River drainage. Rock Creek provides year-round habitat for these native minnow species and resident cutthroat trout, and critical spawning and rearing habitat for migratory BCT from the Bear River. Adult BCT in this system spend winters in low elevation mainstem habitats and then migrate upstream large distances (~75 miles) to spawn in tributaries. Rock Creek is a tributary to Twin Creek which flows into the Bear River. The Rock Creek and Twin Creek drainages provide an estimated 44 miles of tributary habitat that will be directly affected by this project.
This project will install four irrigation diversion fish screens to prevent the entrainment of fish and facilitate upstream migrations into the drainage. Studies have shown that reducing mortality in juvenile fish has a significant effect on population growth through time. This project will prevent entrainment at four different irrigation diversion locations, and should increase BCT and other resident native fish population numbers in the Rock Creek and Twin Creek drainages.