Indonesia Conference Directory

One way to determine the condition of a dam is to compare the pore-water pressure upstream to downstream. If the upstream porewater pressure is higher than downstream, the dam is in good condition. The pore-water pressure at the dam is obtained from the piezometer that is planted inside the dam. If the piezometer is damaged, the condition of the dam core is unknown. This happened at the Lahor dam where of the 9 piezometers, only one was functioning. The porewater pressure of the piezometer is determined by the height of the water column above it so that if the water level is known in the dam core, the porewater pressure will be known. To find out the water table, georadar can be used using a B-scan survey technique along the Lahor dam. The radargram is then processed to obtain the type of material by finding the wave velocity with reference to the water level at the upstream of the dam. The location of the Water table is obtained from reflections due to anomalous material differences. From the results of surface water level analysis in upstream and downstream it can be concluded that the lahor dam is still in good condition.