Investigative Drilling to Begin at Hungry Horse Dam

Media Contact: Diana Cross, (208) 378-5020
Ralph Carter, (406) 387-5241

For Release: June 22, 2005

On Wednesday, June 22, The Bureau of Reclamation will begin an investigative drilling project on the crest of Hungry Horse Dam in western Montana. Beginning in the early morning hours, federal work crews will station a drill rig on the crest of the dam and begin to retrieve core samples from the dam as a means to assess the dam's structural integrity and longevity.

"The investigative drilling will take about two weeks to complete and will help assess the condition of the dam," said Richard Link, Regional Geologist with Reclamation's Pacific Northwest Region. "Stationing of the drill rig on the crest of the dam will necessitate the closure of one lane of traffic. Motorists are urged to use extreme caution in crossing the dam and will be directed through the site by flag crews."

The investigative drilling is a part of Reclamation's regular agency-wide Safety of Dams program, which provides an ongoing assessment of Reclamation's dams and dikes in the 17 Western United States. In addition to continual monitoring through inspections, drill sampling is conducted to allow Reclamation engineers to evaluate potential hazards using contemporary design and construction standards.

A focus of the investigations is to determine how the dam would perform under a variety of conditions and to assess the longevity of the infrastructure components from the core of the dam.

Hungry Horse Dam, standing 564-feet high and located on the South Fork of the Flathead River, is a variable-thickness concrete arch structure with a crest length of 2,115 ft. The project includes a dam, reservoir, powerplant and switchyard. At the time of its completion, the dam was the third largest dam, and the second highest concrete dam, in the world.

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Reclamation is the largest wholesale water supplier and the second largest producer of hydroelectric power in the United States, with operations and facilities in the 17 Western States. Its facilities also provide substantial flood control, recreation, and fish and wildlife benefits. Visit our website at and follow us on Twitter @USBR.