Geophysical techniques

The use of geophysical techniques for the investigation of leakage from dams and lakes is certainly very scarce. This is due to the following reasons: The number of known geophysical techniques is very high, but many technicians engaged in this field are not familiar with the real possibilities they offer. This is partially due to the rapid development during the last few years of most of these techniques; these rapid changes have been mainly derived from the use of integrated electronic circuits. The availability of such units substantially improves data collection, processing and analysis with very high precision and velocity. Both the performance of field tests and the interpretation of the results require the collaboration of specialised and well-experienced technicians. Furthermore, the interpretation of the results is, in many instances, linked to subjective appraisals, and incorrect interpretations are not uncommon. These failures have generated mistrust in the techniques in many cases. Usually, geophysical techniques alone do not provide definitive solutions to dam leakage problems. The results obtained need to be confirmed by other independent techniques.