Benefits

Irrigation

57,183 acres of irrigable land receives a full irrigation water supply. The project’s principal irrigated crops are alfalfa and corn. Other crops include barley, oats, and forage. Irrigated lands are dispersed throughout the project area, and most farm units include irrigated and dry-farmed lands.

Flood Control

No space in the Belle Fourche Reservoir is allocated to flood storage; however, minimal flood control benefits are inherent in the overall operation by impounding flood flows in Owl Creek and diverting water from the Belle Fourche River as needed for the conservation storage.

Recreation

The primary recreation activity at Belle Fourche Reservoir is fishing, with limited boating and water skiing. The South Dakota Department of Wildlife, Parks, and Forestry operates and maintains access roads, sanitary facilities, and boat ramp developments around the reservoir area and the reservoir fisheries.

Belle Fourche Dam

Belle Fourche Dam (formerly Orman Dam), located about 10 miles northeast of Belle Fourche, is a homogeneous earth fill structure that is 6,262 feet long and 122 feet high. It was constructed across Owl Creek, an intermittent stream tributary to the Belle Fourche River. The act of October 27, 1974 (88 Stat. 1486), authorized modification of Belle Fourche Dam to include a new spillway and improvement of the upstream slope protection of the dam to ensure safety. The work was started in 1976 and completed in 1977.

The new earth-lined spillway has a discharge capacity of 4,500 cubic feet per second and is located approximately one mile south of the dam’s right abutment.

The two controlled outlet works consist of two horseshoe-shaped conduits through the dam’s base, one each for the North and South Canals, with 600 and 300 cubic feet per second capacities, respectively.

The dam forms Belle Fourche Reservoir, which has an active conservation capacity of 185,200 acre-feet and a water surface area of 8,000 acres. Dead storage is 6,800 acre-feet.