Tiber Dam, located in southern

Liberty County Liberty County is the name of four counties in the United States: * Liberty County, Florida * Liberty County, Georgia * Liberty County, Montana * Liberty County, Texas See also * Liberty County High School (Florida) * Liberty County High Schoo ...

in northern

Montana Montana () is a U.S. state, state in the Mountain states, Mountain West List of regions of the United States#Census Bureau-designated regions and divisions, division of the Western United States. It is bordered by Idaho to the west, North ...

, USA, is a dam on the

Marias River The Marias River is a tributary of the Missouri River, approximately 210 mi (338 km) long, in the U.S. state of Montana. It is formed in Glacier County, in northwestern Montana, by the confluence of the Cut Bank Creek and the Two Med ...

which forms

Lake Elwell Lake Elwell (a.k.a. Tiber Reservoir) is a reservoir in north central Montana. The reservoir was created by the damming of the Marias River at the Tiber Dam. Lake Elwell was named for Judge Charles B. Elwell (1888–1974), former director of the ...

, also known as Tiber Reservoir. Construction on the dam began in 1952 and it was complete in 1956. Between 1967 and 1969, a dike was added to the southern rim of the reservoir near the dam due to difficulties with the

spillway A spillway is a structure used to provide the controlled release of water downstream from a dam or levee, typically into the riverbed of the dammed river itself. In the United Kingdom, they may be known as overflow channels. Spillways ensure t ...

settling. From 1976 to 1989, the spillway was rehabilitated. The dam is also considered one of the biggest earth-fill dams in the world, along with

Fort Peck Dam The Fort Peck Dam is the highest of six major dams along the Missouri River, located in northeast Montana in the United States, near Glasgow, and adjacent to the community of Fort Peck. At in length and over in height, it is the largest h ...

. The dam is an earth-fill type with a length of and height of . The dike is long and tall. The dam's main

is controlled by three gates and has a maximum discharge of . The dam's auxiliary spillway can release up to and the

outlet works A gatehouse, gate house, outlet works or valve house for a dam is a structure housing sluice gates, valves, or pumps (in which case it is more accurately called a pumping station). Many gatehouses are strictly utilitarian, but especially in the n ...

References

{{Omaha District dams Dams in Montana Buildings and structures in Liberty County, Montana Earth-filled dams United States Bureau of Reclamation dams Dams completed in 1956