Reclamation Issues Security Plan for Two Idaho Dams

Media Contact: John Redding, (208) 378-5212
John Tiedeman, (208) 378-5034

For Release: June 30, 2010

The Bureau of Reclamation's final security decision for two southwest Idaho dams has been released following a lengthy public review process and a full-scale evaluation of potential security vulnerabilities, it was announced today.

The dams include the Lower Embankment of Deer Flat Dams, which impounds Lake Lowell located southwest of Nampa, Idaho; and Anderson Ranch Dam on the South Fork of the Boise River about 28 miles northeast of Mountain Home, Idaho.

A non-structural solution at the Lower Embankment does not call for the closure or re-routing of Riverside Road at this time. However, some roadway construction to enhance security and to control traffic will be in place at Anderson Ranch Dam.

"After careful consideration of all the information, including revisiting our vulnerability analysis, we believe these actions will adequately address the current security risks," said Jerrold Gregg, Snake River Area Manager.

Access control at Anderson Ranch Dam will include raising the dam crest by four feet, constructing a 19-foot one-way traffic lane, asphalt paving, and installing an electronic traffic control system.

"We listened to the concerns raised by the public, and have come up with cost-effective solutions that will have minimal impact to the traveling public, and not jeopardize our goal of ensuring public safety," Gregg said.

The security decisions for the dams followed a lengthy public involvement process that started in late 2008 and ended in December 2009 for two of the Deer Flat Dams. For Anderson Ranch Dam, that process started in August 2009 and concluded in April 2010. Both public involvement efforts created Draft Environmental Assessments which document the environmental effects of alternatives needed to control access across the crest of both dams.

Lake Lowell is an off-stream reservoir formed by three earthfill dams that comprise Deer Flat Dams, known as the Upper, Lower and Middle Embankments. Water to the reservoir is diverted at the Boise River Diversion Dam through the New York Canal.

Anderson Ranch Dam and Powerplant is a multiple purpose structure that provides benefits for irrigation, hydropower, and flood control. The 456-foot high dam was completed in 1950.

Information about the enhanced access control can be found on Reclamation's website at or by calling John Tiedeman, Activity Manager at (208) 378-5034.

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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.

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