ASSESSING THE SOUNDNESS OF CUTOFF WALL OF SUBSURFACE DAM USING SALTWATER DISTRIBUTIONS

Abstract

 Coastal subsurface dams have been playing a vital role of the stable water supply by storing fresh groundwater in the upstream side of the cutoff wall and by preventing the saltwater intrusion in the downstream side. In subsurface dam sites, a method for evaluating the soundness of the cutoff wall is required for proper dam management. Here we investigate the relationship between the soundness of the cutoff wall and the saltwater distribution in the reservoir through experimental and numerical studies. The results show that the saltwater intrusion phenomena vary greatly according to the soundness of the wall, suggesting that the saltwater distribution in the vertical direction measured in subsurface dam sites may be an index to assess the soundness of the cutoff wall associated with the weak area having a relatively high hydraulic conductivity.