Current Development in Oceanography
Volume 1, Issue 1, Pages 1 - 15
(April 2010)
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GEOPHYSICAL LOGGING IN THE COASTAL AQUIFER OF KAVARATTI ISLAND, INDIA FOR GROUND WATER DEVELOPMENT AND MANAGEMENT
S. Balaji
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Abstract:
Ground water occurs as lenses floating over the denser sea water in Kavaratti Island which is the capital city of Lakshadweep group of Islands located in the Arabian Sea, 404 kilometer off Cochin. The fragile fresh water lens occurs in phreatic condition and is in hydraulic continuity with the sea water. The quantity of the ground water is not of much concern in this island but the quality of the ground water is of paramount importance and varies with space, depth and time. The fresh ground water lens is fragile which grades into brackish and saline water. The fresh water lens is also affected by stresses such as ground water draft, tidal influences and rainfall recharge.
In order to study the quality of ground water depth-wise and space-wise, geophysical loggings for the first time in the history of Lakshadweep Islands have been carried out. The subsurface geophysical loggings could be able to demarcate the vertical interface, the thickness of fresh and saline water zone more accurately. The surface geophysical survey viz Vertical Electrical Sounding (VES) could able to map the fresh and saline water interface. Then, the subsurface loggings findings were validated with the surface geophysical results and ground water chemistry which further greatly facilitated to do quantitative analysis for estimating Electrical Conductivity (EC) and to plan for the optimum ground water development and management of this tiny island. |
| Keywords and phrases: electrical logging, resistivity sounding, interface, Kavaratti Island, India. |
| Communicated by Hyo Choi |
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