Integrated Methodology for Delineation of Salt-Water and Fresh Water Interface Between Kolleru Lake and Bay of Bengal Coast, Andhra Pradesh, India

Abstract

Kolleru Lake is the largest natural fresh water lake located between Krishna and Godavari deltas in Andhra Pradesh in India, is acting as a natural flood balancing reservoir and is fed directly by water from the seasonal rivers Budameru, Ramileru and Tammileru. Land use conversions to aqua-culture and Over-exploitation of groundwater are becoming the sources for salt-water intrusion. Present land use activities has large contribution for the change of water quality. Hydrogeomorphology feature are indicates that paleo beach ridges and buried river courses are potential aquifers around the Kolleru Lake. Though there are number of open wells present in the villages used for potable water earlier, people switched over to imported water as their drinking water source may be due to significant contamination of groundwater resources. Integrated study of remote sensing,, hydrochemistry, hydrogeology and geophysical investigations revealed the extent of salt-water intrusion up to the northern part of the lake which is about 40 km away from the Bay of Bengal coast line. The electrical resistivity of aquifers is less than 1.0 Ωm having salinity of more than 1.2 ppt and the resistivity is around 20 Ωm where the salinity is less than 0.5 ppt, has also served as an excellent criteria for delineating the fresh-water and salt-water interface.