Wolf Creek Dam is on the Cumberland River in south central Kentucky. It provides hydropower, flood control, water supply, and water quality benefits for the Cumberland River system and surrounding region. Lake Cumberland, along with Dale Hollow Dam, Center Hill Dam and J. Percy Priest Dam, provide an adequate supply of water to enhance navigation on the mainstem of the Cumberland River from Celina, Tenn., to the Ohio River. The lake is a source of recreation that has attracted more visitors (4.89 million) than Yellowstone National Park (2.87 million). Designed and constructed during the period 1938-1952, the 5,736 foot-long dam is a combination rolled earth fill and concrete gravity structure. It has a maximum height of 258 feet above founding level. A six- generator-unit power plant, with a capacity of 270,000 KW, is located immediately downstream. US Highway 127 crosses the top of the dam. Lake Cumberland, created by the dam, impounds 6,089,000 acre-feet at its maximum pool elevation of 760. It is the largest reservoir east of the Mississippi and the ninth largest in the United States.
In 1968, muddy flows in the tailrace and two sinkholes near the downstream toe of the embankment signaled serious reservoir seepage problems. Investigations indicated the problems were due to the karst geology of the site characterized by an extensive interconnected network of solution channels in the limestone foundation. Piping of filling materials in these features and collapse of overburden and embankment into the voids caused the problems. The District immediately began an emergency investigation and grouting program between 1968 and 1970 that is generally credited with saving the dam. However, grouting was not a long-term fix and a more permanent solution was sought. After studying numerous alternatives, the District chose to construct a concrete diaphragm wall through the earth embankment into the rock foundation to block the seepage. This wall was constructed between 1975 and 1979.
Since completion of the wall in 1979, District personnel have continued to closely monitor the project. Key instrumentation readings, persistent and increasing wet areas, and investigative borings that encountered soft, wet material at depth in the embankment confirm solution features still exist that have not been cut off. While the original wall interrupted the progression of erosion, seepage has since found new paths under and around the wall and perhaps through defects in the wall itself as erosion of solution features continues.
To address the seepage problems, the District has prepared a Major Rehabilitation Report. It evaluates several alternatives to improve the long-term reliability of the dam. From this analysis, the recommended alternative, is a new concrete diaphragm wall constructed using newer technology that will reinforce the purpose of the original wall. This new wall will start immediately upstream of the right most concrete monoliths and run the length of the embankment into the right abutment which will take it 1,650 feet beyond the existing wall. It will be constructed to a depth which is deeper than the deepest sections of the original wall and as much as 75 feet deeper than the majority of the original wall. The cost is estimated at $309 million. The benefit to cost ratio is 7.1. Construction began in 2006 and is on track to be completed by December 2013.