Tracing the evidence of sea water intrusion in the coastal aquifer of Adhirampattinam, India, using hydro-chemical analysis

Abstract

Exploration of coastal aquifer always leads to change in water table levels that provide room for ingression of sea water. Monitoring of sea water intrusion is essential to determine and predict groundwater deterioration and assess other managerial activities in coastal aquifers. Chemical analysis of groundwater sample is considered as one of the practical methods to assess the quality of groundwater in general and also to identify the sea water mixing with fresh water. Current rates of aquifer abstraction are unsustainable and deterioration of groundwater quality is documented in many parts of India. Utilisation of coastal aquifers as operation reservoirs in water supply management requires the development of tools that facilitate the prediction of aquifer behaviour, understanding of the patterns of movement and mixing between fresh water and salt water. Further, the factors that influence these processes are imperative to manage the coastal groundwater resources. Adhirampattinam in Tamil Nadu, India, a coastal town which has been identified as one of the towns with groundwater quality deterioration in recent times, has been taken up for the present study. Water samples from this town and eight coastal villages along the town were collected for quality analysis over three seasons starting from year 2006 to 2008 for detailed hydro-chemical analysis. The parameters studied are pH, EC, TDS, salinity and other hardness elements, which are relevant to assess not only sea water intrusion but also the connected pollution. The analysis reveals that the area under the study viz. Adhirampattinam town is seriously affected by sea water intrusion and indicates a warning signal to other selected places in the area.