Vulnerability of oceanic islands in the face of climate change vis-a-vis human development is a serious issue at present. Great Nicobar island of Nicobar archipelago in the Indian Ocean is going to face major challenges, owing to its impending development activities. Eastern coastal part of the Island is investigated through exploratory drilling, geophysical investigations, and watertable monitoring. Field investigations show that coralline sand is the major groundwater repository and commonly developed through dugwells. Exploratory drilling down to 100 m depth reveals that underlying Tertiary consolidated aquifer is of limited potential and show increased salinity with depth. Water is also present along the contacts of shale-sandstone. Mean seasonal fluctuation of depth to watertable is 0.18 m. Geoelectrical sections identified promising fresh groundwater zones along the east coast with fresh-water bearing semi-weathered coralline limestone and coralline sand having resistivity of 146-622 Ωm. Based on generated data 3D model of the aquifer system is constructed. Observed soil infiltration rate is 0.3 - 0.5 cm/hr. Specific Capacity of dugwells are about 5 m2/min. Permeability of phreatic aquifer is 5 - 11 m/day and transmissivity is 0.11 – 0.2 m2/min. Optimum yield of unconfined aquifer is 17 - 21 m3/day. Tidal influences on the aquifer system also add complexity to the island's hydrogeological dynamics. Despite challenges of restricted access due to presence of aboriginal tribes in the island, present study provides the maiden set of hydrogeological data for the Island revealing the aquifer disposition, their properties and spatio-temporal behavior.

You do not have access to this content, please speak to your institutional administrator if you feel you should have access.