Studies by the Bureau of Reclamation indicate the 428-MW Hungry Horse Dam and dam foundation in Montana would withstand a large earthquake.
BuRec said its analysis of the effects of seismic loading on the dam foundation concluded dam safety modifications are not needed. Government studies initiated in 2004 focused on the bedrock foundation and the dam abutments. BuRec announced completion of the studies in September.
Information from on-site data collection at the dam and laboratory testing was used in computer models to calculate how seismic loads affected the structure. Independent experts in seismology, geology, foundation engineering, and structural engineering reviewed the studies at various stages, BuRec said.
The studies were conducted as part of the BuRec’s agency-wide Safety of Dams program, which is responsible for ensuring that none of its dams presents an unacceptable level of risk to the public, property, or the environment.
BuRec operates Hungry Horse, on the South Fork of the Flathead River about 15 miles outside Glacier National Park in western Montana. (HNN 8/22/07) The project’s 564-foot-tall, 2,115-foot-long concrete arch dam stores nearly 3.5 million acre-feet of water. The project went on line in 1952.
BuRec noted it continually exercises emergency action plans for all facilities for which it is responsible in 17 western states. Such an exercise is planned for Hungry Horse Dam with local emergency management officials on Oct. 16. BuRec added emergency action plans are discussed and updated with local participants about every three years.