The contractor, a joint venture of Treviicos and Soletanche, began work half a year ago at the 1748m (5733ft) long rolled earth fill and concrete gravity dam. The JV has called in specialised drill rigs and strings from Wirth to install the secant piles as part of its barrier design, which also includes rectangular panels supplied by Hydromill.

Technical assistance for the secant pile work will be supplied by DSI subsidiary American Commercial, Inc. The barrier will have an average depth of 83.8m (275ft), and reinforces a previous concrete structure completed in the early 1970s.

The four-year project was awarded as a US$341.4M contract to the JV in July last year by the US Army Corps of Engineers (USACE), which has had to operate the impounded Lake Cumberland at lower levels and with consequent financial impact.

In mid-2007, USACE released a consultant’s study of the leakage and risk, having earlier in the year lowered the reservoir level to reduce risk of dam failure. The reservoir supplies the 341MW John Sherman Cooper plant, which is owned by East Kentucky Power Cooperative (EKPC).

The JV is using a similar seepage solution and equipment that were employed by Treviico and Rodio on the Walter F George dam, in Alabama.