Geoelectrical studies for delineating seawater intrusion in parts of Konkan coast, Western Maharashtra.

Abstract

A total of 28 Veritical electrical sounding (VES) were carried out in the coastal area of Konkan in Kudal-Malvan region, western Maharashtra to delineate the spatial extent of seawater intrusion into the mainland. Resistivity contouring were carried out at depths of 5, 25, 50, 80 and 100 m which indicated confined aquifer in NE part of the study region comprising unconsolidated sediments. Perhaps this aquifer is recharged from the percolating rainfall and River Karli which is flowing in this region. Very high resistivity feature is observed in the northwestern part due to the presence of laterites. In the southern part, very high conductive zone is observed in SW area near coast indicating extensive influence of saline water from intrusion. Two dimensional modeling of resistivity data over three profiles in the study region show the flow of saline water from the coastal side, partly controlled by the lineaments. It is also observed that the effect of saline water intrusion diminishes from southern to northern part of the region. The depth-conductance maps over the three profiles advocate high salinity at the coastal side.