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Baker Project History (40 KB) (pdf)
General Description| Plan| Development| Benefits

General Description

The Baker Project in east-central Oregon consists of two divisions, the Lower and the Upper. The Lower Division provides a supplemental water supply for about 7,300 acres along the Powder River about 10 miles northeast of Baker, Oregon. The Upper Division provides supplemental water for 19,000 acres, including some contiguous areas previously dry-farmed near the city of Baker.

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Facility Descriptions

Lower Division
The irrigation supply for the Lower Division is stored by Thief Valley Dam, on the Powder River 16 miles north of Baker. Water from the reservoir is released into the river channel, from which it is diverted into the various canals of the district, some 8 miles downstream from the dam. Thief Valley Dam is the only federal facility of the Lower Division. All carriage and distribution facilities were privately constructed. Thief Valley Dam is a reinforced concrete, slab and buttress (Ambursen) structure, 73 feet high and 390 feet long. The original reported (1932) total capacity of Thief Valley Reservoir was 17,600 acre-feet (active 17,400 acre-feet) and covered an area of 740 acres. A sedimentation survey completed in 1992 estimated the total capacity at 13,300 acre-feet (active 13,300 acre-feet) and the surface area at 685 acres.
Upper Division
Facilities of the Upper Division furnish supplemental irrigation water to lands on both sides of the Powder River in Baker County, encompassing an area 7 miles wide and 16 miles long adjacent to and north of the city of Baker. Major features include Mason Dam, Phillips Lake, Lilley Pumping Plant, Lilley Relift Pumping Plant, and recreation facilities.

Mason Dam is a rolled-earth and rockfill structure 173 feet in height with a crest length of 895 feet. Phillips Lake, impounded behind the dam, covers 2,235 acres and has a total capacity of 95,500 acre-feet (active 90,500 acre-feet).

The main Lilley Pumping Plant, consisting of four vertical-shaft turbine-type pumps with a total capacity of 68 cubic feet per second, serves 3,450 acres with water.

The Lilley Relift Plant has three vertical-shaft mixed flow pumps totaling 34 cubic feet per second and capable of serving 670 acres.

Operating Agencies

The Lower Division is operated by the Lower Powder River Irrigation District and the Upper Division by the Baker Valley Irrigation District.

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The discovery of gold in Sumpter Valley in 1861 brought the first settlement of the area. Baker Valley attracted some of the home seekers following the Oregon Trail toward western Oregon. Baker, situated where the old trail entered the valley, was first settled in 1863. Mining attracted many of the pioneers, but stock raising and farming were undertaken by others. Irrigation began in the 1870`s, when farmers seeking to improve the native hay meadows made simple diversions from the streams. Construction of a railroad through Baker Valley in 1884 encouraged expansion of the livestock and lumbering industries.


The Lower Division of the Baker Project was first initiated as a Carey Act project by the Powder Valley Irrigation Company about 1909. After an inactive period of about 10 years, the Baker County Chamber of Commerce and a New York corporation sought the assistance of the Reclamation Service for investigations and studies. In 1921, the Director of Reclamation recommended that investigations of the Baker Project be undertaken. Surveys were begun in September 1921, resulting in a recommendation of the Thief Valley site for construction of a dam. The first phase of the project was approved in 1931.

The Upper Division had been under study since about 1930, with local interest and support continuing throughout the entire period. The present development of approximately 19,000 acres evolved from an earlier plan that contemplated a valley-wide irrigation district. This development, through storage of surplus flows, enhances and stabilizes the water supply for the lands in the Baker Valley Irrigation District, and provides the basis for and does not preclude future ultimate resource development of the basin.


Thief Valley Dam of the Lower Division of the Baker Project was found feasible by the Secretary of the Interior on March 17, 1931 under the provisions of section 4 of the Act of June 25, 1910 (36 Stat. 836) and subsection B of the Act of December 5, 1924 (43 Stat. 702), and approved for construction as a single-purpose irrigation facility by the President on March 18, 1931. The Upper Division was approved by an act of Congress on September 27, 1962, (76 Stat. 634, Public Law 87-706). Authorized purposes include irrigation, flood control, conservation of fish and wildlife, and recreation.


Construction of the Thief Valley Dam of the Lower Division was started September 12, 1931, and completed on May 6, 1932. Construction of Upper Division facilities started in 1965 and were completed in 1968.

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Principal crops produced on both divisions are grain, alfalfa hay, grass hay, pasture, and some seed.

Flood Control

Nearly every year normal high water causes damage by inundation of some farm land in the Baker Valley. Less frequent but higher floodflows have caused considerable damage in the past to residential, municipal, and commercial property.

The Phillips Lake Reservoir (http://www.usbr.gov/dataweb/dams/or00577.htm) has 38,000 acre feet of capacity assigned to flood control. Except for some of the lower-lying farm land, flood regulation is being accomplished through the use of 17,000 acre-feet of space in Phillips Lake assigned exclusively to flood control, and an additional 21,000 acre-feet assigned jointly to irrigation and flood control on a forecast of runoff basis. Water that accumulates in the exclusive flood control space may not be retained for irrigation water supply and must be released as soon as possible within specified discharge and streamflow constraints.

The Baker Project has provided an accumulated $614,000 in flood control benefits from 1950 to 1998.


Most of the 909 acres of the Thief Valley Reservoir area are inundated, with 740 acres of water surface providing about 10 miles of shoreline. A portion of the reservoir area has been set aside for recreational use. Camping, picnicking, and boat launching and mooring facilities have been constructed. Union County administers this site. The reservoir has developed a reputation for excellent fishing for trout, largemouth bass, and black crappie which have been planted in the reservoir. Large numbers of waterfowl use the reservoir, and ducks have established nests.

A total of 5,038 acres in the Phillips Lake area is available for recreational use. There are 2,235 acres of water surface and a shoreline stretching almost 13 miles. Recreation facilities for camping, picnicking, swimming, and boat launching and mooring base been constructed and are administered by the Forest Service. Phillips Lake and most of the drainage above it are within the Wallowa-Whitman National Forest. The reservoir is stocked annually with several species of trout. Many waterfowl rest at the reservoir during migration, especially Canada geese.

Endangered Species Act

The Pacific Northwest Region consults with the NOAA Fisheries and the US Fish and Wildlife Service to ensure that project operations and other activities do not jeopardize ESA-listed Species or their critical habitats. 

Fish and Wildlife Service (FWS) and National Marine Fisheries Service (NMFS) provided Biological Opinions on Reclamation's Operations and Maintenance of 12 projects and associated facilities in the Snake River Basin above Lower Brownlee Reservoir. The Baker Project is one of the 12 projects covered in the Opinions.

If conditions don't change these Opinions should be valid through 2035.

For more information on ESA related activies please go to:

For more information on the fish and wildlife program, please go to:  http://www.usbr.gov/pn/programs/fish_wild/index.html   

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Last updated: Jun 01, 2012