Yellowstone River Diversion Dam


An inspection of the Yellowstone River Diversion Dam in 1956 revealed a crack in the dam due to settlement. Extensive erosion of the streambed had resulted in undercutting of the dam foundation. On January 4, 1957, the Bureau of Reclamation and the Huntley Project Irrigation District signed a repayment contract to repair the dam. The repairs were completed in the fall of 1957.


As the first representative of the United States in the Upper Missouri Valley, Captain Clark of the Lewis and Clark expedition scratched his name and the date of July 25, 1806, on Pompeys Pillar, a large rock landmark overlooking the Yellowstone River. Later, the Yellowstone River became a route for traders, trappers, and pioneers. The earliest settlers in the district were the fur traders, then prospectors and other pioneers came to the area. Some of these people turned to agriculture, cattle raising, or other pursuits; some continued to mine. All contended with the difficulties common to western pioneer life.

The Crow Indian Reservation, established under the ratified treaty of May 7, 1868, included an area much larger than the present reservation. The lands in the Huntley Project, being within the reservation, were not subject to homestead entry and consequently remained undeveloped long after other fertile tracts in the Yellowstone Valley were settled. The cession of lands to the United States by the Crow Indians in 1904 included those in the Huntley Project and opened the way for irrigation and settlement.


An act of Congress, approved April 27, 1904, provided that the Reclamation Service should make surveys and investigations for the irrigation of the irrigable area lying south of Yellowstone River and extending along the Bighorn River as far southeast as the Fort Custer military reservation.

Surveys began in August 1904, and in October 1904 the project was designated for early development. Detailed plans were prepared and reviewed by a board of engineers which, on February 26, 1905, declared the project feasible.


The project was authorized by the Secretary of the Interior on April 18, 1905.


Construction began October 6, 1905. The first water was delivered in 1908. The Pryor Division was completed in 1908, the Eastern Division in 1914, and the Fly Creek Division in 1915. The High Line Canal was enlarged in 1917 from 60- to 100-cubic-foot-per-second capacity.

Initial construction of the project did not require a diversion dam since the Main Canal intake on the Yellowstone River was level with the riverbed. Development of additional lands by local interests requiring increased diversion necessitated the construction of a small diversion dam which was completed by the Huntley Project Irrigation District in 1934. Anita Dam and Reservoir were constructed by CCC forces and completed in 1937.

RegionFacilities in Great Plains | Great Plains Home Page
Dam TypeConcrete weir
WatercourseYellowstone River
Location On the Yellowstone River, about 2 miles southwest of Huntley, Montana.
Original Construction1934
Modified Construction Rehabilitated in 1957
National ID Number
Hydrologic Unit Code

Structural Height10.50 ft
Hydraulic Height (Normal Operating Depth at Dam)8.00 ft
Top Parapet (Elevation)
Spillway Crest Elevation
Crest Elevation3,004.00 ft
Crest Length325.00 ft
Crest Width
Base Width
Volume of Dam Construction Materials 2,000.00 cu yds
Streambed at Dam Axis
Top of Exclusive Flood Control Pool (Elevation)
Top of Joint Use Pool (Elevation)
Top of Active Conservation Pool (Elevation)
Top of Inactive Conservation Pool (Elevation)
Top of Dead Storage Pool (Elevation)

Hydraulics & Hydrology
Total Water Storage at Elevation
Maximum Water Surface Elevation
Normal Water Surface Elevation
Spillway TypeConcrete weir
Auxiliary Spillway
Spillway Capacity at Elevation
Auxiliary Spillway Capacity at Elevation
Uncontrolled Spillway Capacity at Elevation
Outlet Works Capacity at Elevation
Diversion Capacity at Elevation600.00 cfs at 3,004.00 ft
Drainage Area
Hydrometeorological Report (HMR)
Probable Maximum Flood (PMF) Report

Contact Information
TitleArea Manager
OrganizationMontana Area Office
AddressP.O. Box 30137
CityBillings, MT 59107-0137
Phone (Fax)406 247-7338
Phone (Office)406 247-7300
OrganizationHuntley Project Irrigation District
AddressPO Box 61
CityBallantine, MT 59006
Phone (Office)406 967-3400

Last updated: Apr 02, 2013