The Bureau of Reclamation recently completed a 4-year effort to analyze the effects of seismic loadings on the foundation of Hungry Horse Dam. The studies were initiated because of concerns about how the dam might perform during a major earthquake. Results of the studies indicate that the dam and foundation will perform satisfactorily during large earthquakes.

The studies, begun in 2004, focused on the bedrock foundation and the abutments of the dam. Information obtained from onsite data collection and laboratory testing was used in computer models to calculate how different seismic loads affected the structure. The study was reviewed at various stages by independent experts in seismology, geology, foundation engineering, and structural engineering.

This seismic study is part of Reclamations ongoing Safety of Dams Program to ensure that no Reclamation dam presents an unacceptable level of risk to the public, property, or the environment. With a total storage of almost 3,500,000 acre-feet of water, a failure of Hungry Horse Dam would affect people living in Hungry Horse, Columbia Falls and farther downstream.

Even though the current studies show there is a very low likelihood of a Hungry Horse Dam failure, Reclamation continually exercises its emergency action plans for all the facilities under its responsibility. Such an exercise is scheduled for Hungry Horse on October 16 with local emergency management officials. Emergency action plans are discussed and updated with local participation about once every three years.

Hungry Horse, completed in 1953, is owned and operated by the Bureau of Reclamation and has the capacity to provide 428 megawatts of power. It is located on the south fork of the Flathead River about 15 miles from the west entrance to Glacier National Park.