News Release Archive

Reclamation Begins Seismic Exploration Program at Anderson Ranch Project

Media Contact: John Redding, (208) 378-5212, jredding@pn.usbr.gov
Richard Link, rlink@pn.usbr.gov

For Release: April 22, 2009

The Bureau of Reclamation announced today that further investigations of Anderson Ranch Dam are warranted due to a 2007 reevaluation of seismic risk of the dam, located on the South Fork of the Boise River about 28 miles northeast of Mountain Home, Idaho.

As part of this effort, Reclamation drill crews will mobilize at the dam to begin an exploration program beginning in early May and continuing through September. Drill crews will collect data for use in more detailed seismic studies of the dam and its foundation.

The Anderson Ranch Dam technical review and subsequent investigations are part of Reclamation's Safety of Dams (SOD) Program which routinely evaluates the structural integrity of Reclamation dams under various conditions to identify potential public safety risks.

"Anderson Ranch Dam is currently considered safe under normal operating conditions," said Larry Wolf, Reclamation's Pacific Northwest Region SOD program manager, "but our first priority is public safety, and our risk assessment report indicates that the potential seismic risk at Anderson Ranch Dam require us to take a more detailed look at the structure, its foundation, and the geological makeup of the area."

When completed in 1950, the 456 foot structure was considered the highest earthfill dam in the world. The reservoir has an active storage capacity of more than 413,000 acre-feet and is one of three large water storage dams on the Boise River. Reclamation owns, operates and maintains the dam, associated structures and the 40 MW hydroelectric powerplant located at its base.

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