Integrated Geophysical Approach for Rapid & cost Effective Investigations & Monitoring of Dams

Dams in the country represent a major investment and huge benefits to population in terms of irrigation, power and flood control. Most of the big dams are very old and regular monitoring and maintenance of these dams is of utmost importance for continuing benefits. Unlike soil investigations, critical nature of dams, does not permit traditional invasive inspections by means of drilling, and such inspections are best avoided unless extremely important, and are done only when problem is too grave.

Although long recognized that dams need periodic inspection and monitoring, it has only been recently recognized that geophysical surveys can supplement the results of standard inspection and monitoring techniques. Geophysical surveys have been performed on a number of dams around the world, including india, and have yielded extremely useful insight into dam conditions. Seismic refraction surveys have been performed to provide a cross-section of the dam embankment and foundation materials in terms of seismic characteristics. Self Potential (SP) surveys have been performed to investigate seepage conditions within dam embankment and foundation materials, and abutment materials. Electrical Resistivity Tomography is also routinely performed on dams to determine internal saturation conditions in dams. ReMi is effectively used to determine shear wave velocities (Vs) in dams.

The purpose of this paper is to demonstrate as to how these geophysical techniques are applicable to solve various issues related to dams. These geophysical surveys may find future use as monitoring tools applied to various dams.