Central Utah Project Units
The Vernal Unit is located near the city of Vernal in the Ashley Valley of northeastern Utah and lies within the Green River Basin of the Upper Colorado River Basin. The Vernal Unit provides supplemental irrigation water to land in Ashley Valley of eastern Utah, as well as municipal and industrial water to local communities. The primary storage feature of the Vernal Unit is Steinaker Dam which impounds 38,000 acre-foot capacity Steinaker Reservoir located 3.5 miles north of Vernal, Utah. Steinaker Dam is a zoned earthfill structure with a height of 162 feet, a crest length of 1,997 feet, and a volume of 1,892,000 cubic yards of material.
Other principal features of the Vernal Unit include Fort Thornburgh Diversion Dam on Ashley Creek and Steinaker Feeder Canal. Excess spring flows from Ashley Creek are diverted by Fort Thornburgh Diversion Dam on Ashley Creek, four miles northwest of Vernal. From the diversion dam, the water is conveyed eastward to Steinaker Reservoir through the 2.8 mile-long Steinaker Feeder Canal. Reservoir water is released to Steinaker Service Canal and conveyed south 11.6 miles to existing canals and ditches to provide supplemental irrigation water to approximately 14,781 acres. This water partially replaces Ashley Creek water, including releases from privately constructed reservoirs upstream. Some of the replaced water is used on lands upstream of Steinaker Service Canal and some is diverted from Ashley Springs on Ashley Creek into the municipal pipelines through which about 1,600 acre-feet of water is delivered annually to the communities of Vernal, Naples, and Maeser. Prior to construction of the Vernal Unit features, flows in Ashley Creek dwindled to an inadequate water supply by late summer.
The Vernal Unit, along with the Jensen, Bonneville, and Upalco Units, was authorized by the 1956 Colorado River Storage Project Act. Construction of Vernal Unit irrigation facilities started on May 14, 1959 and was completed in 1963. Project facilities were turned over to the Uintah Water Conservancy District for operation and maintenance on January 1, 1967. Construction of drainage facilities was initiated in 1970 and completed in 1977. Modifications were made to the drainage facilities in 1982.
In 1993, Steinaker Dam and Reservoir began modifications to comply with the Safety of Dams requirements. These modifications included excavating the clay foundation material located downstream of the toe of the dam. Dam modification was completed in September of 1994. The construction resulted in a stability berm at the downstream toe.
Located in Uintah County in northeastern Utah, the Jensen Unit was the second unit of the Central Utah Project to be completed following the Vernal Unit. The Jensen Unit is part of the Initial Phase of the Central Utah Project, and was authorized by the 1956 Colorado River Storage Project Act (70 Stat. 105).
The Jensen Unit develops about 22,600 acre-feet of water annually including: 18,000 acre-feet for municipal and industrial (M&I) uses and 4,600 acre-feet for irrigation. Red Fleet Dam and Reservoir, located on Big Brush Creek about 10 miles northeast of Vernal, Utah, is the main storage feature of the unit. The dam is 144 feet high and impounds 26,000 acre-feet of water (24,000 acre-feet of active storage). At full pool the reservoir's surface area is 521 acres. Construction of the dam began in 1977 and was completed in 1980. Irrigation water from the reservoir serves about 4,080 acres of agricultural lands within the unit boundaries that produce alfalfa, barley, corn silage, and irrigated pasture.
Other Jensen Unit facilities are the Tyzack Pumping Plant and Tyzack Aqueduct. Water is pumped from Red Fleet Reservoir by Tyzack Pumping Plant and then conveyed by Tyzack Aqueduct to the Ashley Valley Water Treatment Plant. A continuation of the Tyzack Aqueduct distributes the treated drinking water from the plant to the city of Vernal and Jensen Water Districts.
Upon completion of construction, Jensen Unit facilities were transferred to the Uintah Water Conservancy District (UWCD)on October 1, 1988. Total estimated unit construction costs were $33,263,000. Under the supervision of the Bureau of Reclamation, the UWCD is responsible for routine, daily operations and maintenance of the unit, and for repayment of the reimbursable portions of the construction costs (about $30.5 million).
Recreation facilities at Red Fleet Reservoir consist of boat launching facilities, campground and picnic areas all administered by the Utah Division of Parks and Recreation as part of Red Fleet State Park.
The largest unit of the CUP, the Bonneville Unit collects and distributes water in both the Uintah Basin of eastern Utah, and the Bonneville Basin of central Utah. The Bonneville Unit provides water for irrigation and municipal and industrial uses. In addition, Bonneville Unit systems provide water for maintenance of aquatic habitats in natural streams, open water recreation, and flood control. For purposes of planning and construction the Bonneville Unit itself was divided into component systems. Working together, the systems develop, store, and transport water resources for the benefit of the people of Utah.
Several systems of the Bonneville Unit are complete and functioning. The Utah Lake Water Delivery System, the "final link" needed to complete the CUP, is under active construction and is scheduled for completion in 2021.
Bonneville Unit Systems include:
Unbuilt Units: Upalco, Uintah, Ute Indian
Because of its size and complexity, Reclamation divided the CUP into six units to be built in two phases to facilitate planning and construction. The “Initial Phase” of the CUP was divided into four independent units: Jensen, Vernal, Upalco, and Bonneville which were authorized by the 1956 Colorado River Storage Project Act. The first three units (Jensen, Vernal, Upalco) proposed construction of reservoirs to increase water supplies in the Uintah Basin. The Bonneville Unit proposed additional storage in the Uintah Basin and a transbasin diversion to the Bonneville and Sevier RiverbBasins.
To allow for the full diversion of water from the Uintah Basin under the Bonneville Unit, Reclamation and the Central Utah Water Conservancy District (CUWCD) negotiated with the Ute Indian Tribe which held superior rights on the Duchesne River. The Tribe agreed to defer their paper rights for 40 years in exchange for water development projects to make real water available to tribal members.
To meet these water rights obligations and to fully develop Utah’s share of the Colorado River, Reclamation planned two additional units of the CUP as part of the “Ultimate Phase.” Under the 1968 Colorado River Basin Project Act, Congress conditionally authorized construction of the Uintah Unit, and feasibility investigations for the Ute Indian Unit. The Uintah Unit consisted of two reservoirs on the Uintah and Whiterocks rivers to supply irrigation water to Indian and non-Indian lands. The Ute Indian Unit contemplated various plans for diversion from the Green River into the Uintah Basin.
A long period of difficult issues involving the problematic and sometimes controversial water rights agreement with the Ute Tribe, changing priorities in the state of Utah over development of its share of the Colorado River, geologic problems, and cost increases, the Upalco, Uintah, and Ute Indian Units were never built.
Following the passage of the 1992 Central Utah Project Completion Act, the CUWCD working with the office of the Secretary of the Interior and with assistance from Reclamation, recently completed the enlargement of the Big Sand Wash Reservoir as a replacement project for the Upalco Unit.