WALLA WALLA, Wash. – The Walla Walla District of the U.S. Army Corps of Engineers invites the public to participate in a Wednesday, Aug. 17, meeting about a recently improved safety rating of the Mill Creek Storage Dam. The meeting will be held be held at the Bennington Lake boat ramp parking lot beginning at 9:30 a.m.
This update meeting is part of an ongoing nationwide “Dam Safety Action Classification” (DSAC) safety effort by the Corps at each of its dams including the two dams at the Mill Creek Project—the Diversion Dam on Mill Creek and the Storage Dam that holds Bennington Lake. Each Corps dam was initially assigned a DSAC rating on a scale of I to V (one to five) with a DSAC-I being least safe.
An initial May 2008 DSAC rating assigned Mill Creek Storage Dam was DSAC-I or “urgent and compelling” based on a brief records-only review. The Corps headquarters dam safety Senior Oversight Group recently improved the Mill Creek Storage Dam DSAC rating to DSAC-III or “high priority” based on a completed Issues Evaluation Studies (IES) report and ongoing “interim risk reduction measures.”
“Public safety is our highest priority, and keeping the public informed of our progress in making our dams safer is an important part of that effort,” said Lt. Col. David Caldwell, district commander. “We’d like to share specific details of this improved rating.”
The initial 2008 rating was primarily due to potential dam seepage and piping issues within the foundation of the dam when Bennington Lake is more than 17 percent full for an extended period of time. In Oct. 2009, the Storage Dam was upgraded by the Senior Oversight Group to DSAC-II or “urgent” after additional data gathering and a preliminary Issues Evaluation Studies (IES) report showed the risk for dam failure under normal operations was not as high as originally estimated. The District also began implementing a series of “interim risk reduction measures” in 2008 to improve public safety. Corps officials held a series of public meetings about the Storage Dam and separate Mill Creek Diversion Dam. The Diversion Dam has carried a DSAC-II rating since its initial classification in January 2009 and is undergoing further review.
Additional information about the District is available on its website at www.nww.usace.army.mil. See the “Dam Safety” tab for an update about the Mill Creek Storage Dam.
Release no. 11-114