In addition, Palisades Dam, a multipurpose reservoir on the Snake River, provides flood control regulation, recreation, power, and holdover storage during years of average or above average precipitation to Minidoka Project lands. Ririe Dam, constructed by the Corps of Engineers on Willow Creek, also provides flood control regulation on this Snake River tributary within the Minidoka Project area. A full water supply is furnished to 216,796 acres and a supplemental supply to 946,846 acres. Water from Palisades Reservoir on the Palisades Project is instrumental in helping meet the Minidoka Project water requirements. Much of the power developed on the project is used for pumping water to lands lying above the gravity canals and for pumping drainage water.
Power also is furnished to several small communities in the area.
The Upper Snake River Division is primarily a storage facility to furnish a supplemental water supply to lands already under irrigation from private systems. The lands are in Fremont and Madison Counties. The Fremont-Madison Irrigation District, composed of 40 different canal companies, comprises approximately 110,000 acres. Island Park Reservoir covers 7,794 acres within the Targhee National Forest. Henrys Fork River begins 31 miles above Island Park Dam at Henrys Lake, but actually has its source in the various headwaters of tributaries to Henrys Lake.