Prevention and Detection of Leakage 785 TECHNIQUES FOR PREVENTION AND DETECTION OF LEAKAGE IN DAMS AND RESERVOIRS

Leakage is a major safety issue that, if left unchecked, may result in dam failure by various mechanisms. There is enormous pressure on dam operators to repair leaks without significant delays. Frequently, the need to reduce the risk of failure or control water loss has led to costly remedial repairs that are planned and executed without a complete understanding of the problem. A lack of appropriate leakage investigation and monitoring can result in repairs that are unsuccessful in controlling or reducing leakage. In the last few decades, a series of new hydrological techniques have been developed to help in the assessment of leakage and seepage in dams. It is important to make these techniques available to the engineers responsible for dam construction and management so that they become aware of these tools. The available literature on dam leak studies is relatively limited with regard to the use of these techniques when assessing dam leakage. It is difficult to find case studies that discuss integrating the use of several of these techniques in comprehensive evaluations that lead to successful leakage mitigation. These techniques allow identification of recharge zones, preferential paths, and transit times, which aid in monitoring and mitigating the dam leakage. The paper includes description of the techniques and projects in the United States and abroad involving prevention and detection of dam and reservoir leakage, including leakage evaluation, analysis, design, construction, and post-construction verification of repairs.