Tour of Center Hill Dam Safety Construction
U.S. ARMY CORPS OF ENGINEERS, Nashville District
When: Friday, April 21, 8:00 am – 2:00 pm
Where: Bus pickup and return is at the Hilton Garden Inn Nashville Downtown, 305 Korean Veterans Blvd., Nashville. The Hilton Garden Inn's transportation loading area is at the corner of Third and Peabody, behind the hotel's main entrance.
Registration: $80 per person includes motorcoach transportation, guided tour, box lunch and beverages.
Security Notice: Due to US Army Corps of Engineers security regulations, this tour is available to U.S. citizens only; foreign nationals are not eligible to participate. Attendees will be required to:
- complete this VISITOR'S FORM and return to ASDSO by Friday, April 7, and
- show government-issued identification, e.g. valid driver's license or passport, upon arrival at the tour site.
Other Requirements: Please wear steel toed or sturdy shoes, long pants, and a short or long sleeved shirt.
Tour Description: The 250-foot high Center Hill Dam lies about 100 river miles upstream of Metropolitan Nashville and impounds the second largest flood storage reservoir within the USACE Nashville District’s Cumberland River Basin. A Dam Safety modification project was approved in 2006 to lower the risk of failure to within standard tolerable risk guidelines. The combination earthen and concrete main dam and an earthen auxiliary dam were built in the 1940’s on highly solutioned limestone with little to no foundation treatment, as was typical at that time. By 2005, increasing seepage issues caused the project to be classified as Dam Safety Action Classification (DSAC) 1, the highest priority for USACE dam remediation.
Risk reduction measures completed to date include a major main dam grouting contract followed by deep foundation barrier wall construction. The barrier wall component was of unprecedented scale-- in terms of depth and accuracy of drilling required for the barrier wall construction. The 2.5’ thick concrete barrier extends as far as 308’ below the top of the dam into the karst foundation and is the permanent seepage barrier protection for the main embankment. The final major construction effort is the saddle dam repair, a concrete reinforcing berm downstream of the saddle dam embankment.
Thalle Construction Co. began work in the fall of 2016 on this $42.9M effort and the berm will be built primarily of Roller Compacted Concrete (RCC). Foundation excavation is expected to be underway in April. The unique project also has one of the country’s largest geotechnical fuse plugs which was retrofit in the 1990’s for additional project spillway capacity. The District also manages issues with alkali aggregate reactivity (AAR) in the concrete dam. The tour will also explore these project features.