The Problem is the Solution: A History of Seepage, Piping, and Remediation in a Karst Foundation at Wolf Creek Dam

In 1968, about 17 years after first being impounded, wet areas, muddy flows in the tailrace and sinkholes in the downstream toe of the embankment signaled serious foundation seepage problems at Wolf Creek Dam. The Nashville District Corps of Engineers began an emergency investigation, instrumentation, and grouting program that was generally credited with saving the dam. Data generated revealed an extensive interconnected network of solution features in the limestone foundation and inadequate foundation treatment measures taken during construction. It was decided grouting alone could not be relied upon as a long term solution in such geology. Thus, from 1975 through 1979, a concrete cutoff wall was installed through the embankment and into the rock foundation. Since that time the project has been closely monitored. Based on instrumentation readings, investigations, and visual observations, it is apparent seepage has found new pathways through features left untreated by the first wall. The Nashville District will be installing a new wall upstream of the existing wall to a greater depth and lateral extent to cut off remaining seepage paths. (Proceedings includes full paper) 10 pp.