To study the extent of salinity intrusion in Kuppam river basin, Groundwater Division of CWRDM has set up an observation well network in the entire Kuppam river basin. The results of one year of observations of well data are discussed here. Monthly data collected from 41 permanent observation wells and 4 surface water stations in Kuppam River Basin have been processed. The elevation of observation well, its proximity to the surface water bodies, tidal influences, geomorphology, climate and nature of geological formation are the factors influencing the salinity of well water in the study area. Analysis of selected water samples from Kuppam river shows that the extent salinity is 20 km extending from the sea to the land area during Pre and Post monsoon season. The extent of salinity is observed 12 kms extending from the sea to the land during monsoon season. A field model has been developed in Kuppam coast to estimate the width of sensitive zone. The estimated width of sensitive zone of estuarine zone varies from 2.5 km to 8.5 km from the shore to the land from the well data. The width of the sensitive zone is estimated to be of 730 m along the coast from the shore.
