Study of the Deformation of Koyna Dam Using the Global Positioning System

Large engineering structures such as dams, though essential for development, are also a potential hazard, causing loss of human lives and property, in case of their failure under excessive deformations. Hence, monitoring dam deformations has assumed great importance worldwide. Classical geodetic techniques, and more recently, the revolutionary space geodetic technique: Global Positioning System (GPS), are valuable tools for generating important input data to monitor such deformations. A project for crustal dynamic studies in the Koyna Region in Maharashtra, India, using GPS, has been taken up, which also includes the deformation studies for Koyna Dam. A GPS network has been established for this purpose, and observed in two sessions viz. December 2000 and May 2001. The study results indicate a definite correlation between the change in reservoir water level and the deformation of the dam. The results obtained using the conventional methods are found in close agreement with the GPS-derived results, thus proving GPS to be an effective tool for dam deformation studies.