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Central Utah Project - Vernal Unit

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Vernal Unit Project History (1.6 MB) (pdf)
General Description| Plan| Development| Benefits


General Description

The Vernal Unit of the Central Utah Project is 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. Principal constructed features of the unit are Fort Thornburgh Diversion Dam and Steinaker Feeder Canal, through which surplus flows of Ashley Creek are conveyed to the off stream Steinaker Reservoir. Water stored in the reservoir is released into Steinaker Service Canal and delivered to pre-project irrigation canals and ditches. A supplemental water supply is provided to about 14,781 acres. This water will partially replace Ashley Creek water, including releases from privately constructed upstream reservoirs. 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. Of the six units which comprise the Central Utah Project, the Vernal Unit is the only unit that is complete; it was completed in 1963.

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The unit features store and distribute the excess spring flows of Ashley Creek. In years prior to the project, Ashley Creek flows dwindled to an inadequate water supply by late summer. Water stored in Steinaker Reservoir can now be released to provide supplemental water to about 14,781 acres of land. Municipal water is supplied to the communities of Vernal, Naples, and Maeser, Utah.

Facility Descriptions

Steinaker Dam and Reservoir

Flows of Ashley Creek are stored by Steinaker Dam, constructed off stream in Steinaker Draw about 3.5 miles north of Vernal. This 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. Steinaker Reservoir has a total capacity of 38,173 acre-feet, and a surface area of 820 acres.

Diversion and Carriage Facilities

Water from Ashley Creek is diverted by Fort Thornburgh Diversion Dam on Ashley Creek, 4 miles northwest of Vernal. From the diversion dam, the water is conveyed eastward to the 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.

Part of the water in Steinaker Service Canal is provided directly for unit lands downstream of the canal as a supplemental supply, and part is used as a replacement supply to these lands in exchange for natural streamflow and storage releases from existing reservoirs that are diverted upstream. Exchange water made available upstream is used for municipal purposes in Vernal, Maeser, and Naples, and for supplemental irrigation of unit lands upstream of Steinaker Service Canal. The municipal water is diverted from Ashley Springs on Ashley Creek and is distributed through existing facilities.

Operating Agencies

Project facilities were turned over to the Uintah Water Conservancy District for operation and maintenance on January 1, 1967.

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In the summer of 1776, ten Spaniards led by Father Escalante, a Catholic Priest, passed through the valley in their quest for a direct route from Santa Fe, New Mexico to Monterey, California. These were the first white men to enter and they reported a land dry and arid with sandy soil. The vegetation was sage brush, cactus, and desert plants. They also recorded wild animals and Indians living there.

General William H. Ashley entered the area in 1825, leaving his name to both Ashley Creek and Ashley Valley. He was on a trapping expedition with Jim Bridger and Andrew Henry, founder of the Rocky Mountain Fur Company.

Pardon Dodd built the first house in Ashley Valley in 1873 out of timber and mud. He was the Indian agent at White Rocks from 1868 to 1872 prior to moving into this valley to become a stockman. Agriculture began in the valley in the spring of 1874 when a ditch was dug to irrigate land on the Dodd ranch. Settlers from Salt Lake City arrived in 1877 and by 1880, three large canals, Ashley Central, Ashley Upper, and Rock Point, were built.

It was necessary for the settlers to make their communities selfsupporting because of isolation due to the bad roads and lack of railroad facilities. The first crops grown in the valley were corn, wheat, and potatoes. Alfalfa, small grains and pasture have been the principal crops of the unit area. Then, as well as now, there were few immediate cash crops, livestock and animal products being the source of cash income. The Ashley Valley area is well adapted to the production of livestock because of the excellent pasturage afforded by the Uinta Mountains and also the irrigated pasturage in the valley. Sheep and cattle raising are both important branches of livestock production there. Due to the rapidly growing population, agriculture, and livestock production, it was necessary to develop a project that would provide the Ashley Valley with municipal, industrial, and irrigation water.


The Central Utah Project plan has evolved from investigations of various independent projects. Continuous investigations have been conducted by the Bureau of Reclamation since 1945 from a plan which started in 1902 on the Strawberry Valley Project. It was recognized early in the investigations that the project was of such magnitude and complexity that it should be divided into separate units to facilitate planning and construction. A feasibility report was published in February 1951.


Initial Phase of the Central Utah Project, including the Jensen Unit, was authorized as a participating project of the Coloraldo River Storage Project by act of April 11, 1956 (70 Stat. 105).

Project Funding

Repayment of project costs is scheduled as follows: $98,000 pre-payment from the Colorado River Development Fund and contributions; $231,000 non-reimbursable fish and wildlife, recreation, and highway improvement credits; $8,020,050 from Upper Colorado River Basin Funds credited to the State of Utah; $606,000 from municipal and industrial water users; and $1,500,000 to be repaid by Uintah Water Conservancy District in 50 equal annual installments. The District commenced repayment of its obligation in 1966 and as of September 1982, has repaid $997,433.


The Vernal Unit repayment contract between the Uintah Water Conservancy District and the United States was executed June 15, 1958, and validated by the courts November 25, 1958. Construction of irrigation facilities started on May 14, 1959, and was completed in 1963. 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.

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Principal crops grown on the project lands are barley, corn, oats, alfalfa, corn silage, and irrigated pasture. The total estimated project cost is $10,402,000. Of this amount, $9,602,000 has been allocated to irrigation, $569,000 to municipal and industrial water, and $231,000 to non- reimbursable fish and wildlife and other costs.

Municipal and Industrial

Water 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, Utah.


Recreation facilities at Steinaker Reservoir are administered by the Utah Division of Parks and Recreation. Recreation facilities consist of boating, waterskiing, and fishing. There were 65,663 recreation use visits spent in the reservoir area during 1996.

Hydroelectric Power

There is no Hydroelectric power that is produced by the Central Utah Project - Vernal Unit.

Flood Control

No space or funds were allocated to flood control; therefore, no formal flood control plan has been made for Steinaker Reservoir. However, when space is available, nonproject flows of Ashley Creek may be temporarily stored in the Steinaker Reservoir to reduce flood flows, if directed by the Ashley Creek River Commissioner and concurred with by the Provo Area Office and the Uintah Water Conservancy District.

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Last updated: Apr 21, 2011