Owl Creek Unit of the Pick-Sloan Missouri Basin Program is in Hot Springs County in north-central Wyoming, west and north of the city of Thermopolis. Owl Creek heads in the Absaroka Mountains and flows eastward, north of the Owl Creek Mountains, joining the Bighorn River 6 miles north of Thermopolis. The unit comprises a narrow valley extending about 30 miles westerly from the mouth of Owl Creek. The development provides supplemental water to 12,740 acres of irrigated land to stabilize the agricultural economy of the area. Principal features of the development include Anchor Dam and Reservoir and pumping facilities to deliver water to the three distinct areas of the unit.
History
Early History
After early settlement of Owl Creek Valley in 1871, the development of irrigated agriculture followed rapidly. The first water rights were recorded in 1880. By 1905, the inhabitants of the area realized that the irrigated acreage had surpassed the available water supply from the creek. However, individual landowners were permitted to continue making application for water rights, and rights for approximately 28,800 acres are now recognized on the stream, although the average cropped acreage is about 17,000.
Investigations
For more than 50 years attempts have been made by local farmers and ranchers to sponsor a project for augmenting the supply of irrigation water in Owl Creek. As early as 1909, a small group of landowners employed an engineer to determine whether additional water could be brought into the Owl Creek drainage area from Wind River. Beginning about 1934, various organizations were formed to develop specific storage or pumping facilities. After experiencing extreme shortages of irrigation water during 1930-40, the assistance of the Bureau of Reclamation was requested in developing a program to relieve excessive fluctuations in the water supply.
Reclamation conducted a series of investigations beginning in 1941 and discussed a storage development with local water users in 1946. These discussions culminated in 1947 in teh formation of the Owl Creek Irrigation District, which included 13,324 acres of irrigated land. This district serves as the contracting entity for the supplemental supply to be furnished from Anchor Reservoir and for the development under the Lucerne pumping system.
Authorization
The project was authorized by the Flood Control Act of December 22, 1944, Public Law 534, which approved the comprehensive plan set forth in Senate Document 191 and House Document 475, as revised and coordinated by Senate Document 247, 78th Congress, 2d Session.
Construction
Construction of Anchor Dam began in 1957 and was completed in 1960. Lucerne Pumping Plants No. 1 and 2 and the Lucerne Relift Canal were completed in 1956.
Operating Agency
Operation and maintenance are performed by the Owl Creek Irrigation District.
BENEFITS
Irrigation
Livestock production is the major enterprise in the unit. Grains and hay for livestock are the principal crops. Sugar beets and corn also are grown in the lower area. Stabilization of the water supply makes possible the extension of these row crops into the middle area.
Recreation and Fish and Wildlife
Benefits for fish and wildlife and recreation opportunities are provided.
Plan
The Owl Creek Unit features Anchor Dam and Reservoir on the South Fork of Owl Creek, about 25 miles west from Thermopolis, Wyoming. The water supplied from Anchor Reservoir is augmented during periods of short supply by pumping from the Bighorn River. The pumping plants required construction and rehabilitation of pump canal facilities. Distribution facilities are privately owned.
Anchor Dam and Reservoir
Anchor Dam is a concrete thin-arch dam in a narrow gorge on the South Fork of Owl Creek. The structure is 208 feet high with a crest length of 660 feet. The spillway is an uncontrolled overflow type notched into the central part of the dam, with a maximum discharge capacity of 13,500 cubic feet per second. Reservoir discharge is provided by two 30-inch-diameter conduits through the dam at the left end of the spillway, controlled by 30-inch hollow-jet valves located in a valve house on the downstream face of the dam. One 3.25-foot-square slide gate is provided at the upstream face of the dam for each outlet for emergency closure and servicing. A 42-inch-diameter conduit through the dam is provided for evacuation of the reservoir controlled by a 3.25-foot-square slide gate at the upstream face. Anchor Reservoir has an active conservation capacity of 17,205 acre-feet with a surface area of 437 acres. During the initial filling of the reservoir, a series of sinkholes and leaks developed. To correct these conditions, sinkholes were filled and leaks blanketed with earth. Progress has been made in improving the effectiveness of the reservoir and some benefits are realized for irrigation and flood control. Usually enough water can be stored during runoff to extend the irrigation deliveries into late July or early August.
Lucerne Pumping Plants
Lucerne Pumping Plant No. 1 is about 3.5 miles north of Thermopolis. It consists of two pumps operating under a 67-foot head, which deliver 40 cubic feet per second to the Lucerne Ditch, and two pumps operating under a 136-foot head delivering 44 cubic feet per second into the Lucerne Relift Canal to supply Plant No. 2. Plant No. 2 has two pumps operating under a 24.5-foot head to relift 33 cubic feet per second from the Lucerne Relift Canal to the Dempsey Ditch. This plant, of open-type construction, is at the end of the Lucerne Relift Canal. The ditches and other irrigation facilities are provided by and maintained by the irrigation district. Operation and maintenance are performed by the Owl Creek Irrigation District.
