Groundwater modelling study for the assessment of seawater intrusion in the coastal region of thoothukudi

Abstract

Water is a main vital source for all the living things in this world. Groundwater in coastal areas is relatively vulnerable to contamination by sea water. It is importance to assess the suitability of groundwater for drinking, domestic, industrial and irrigation purposes. Seawater intrusion in coastal aquifers is the common worldwide problem. Seawater intrusion promotes the salinity of groundwater, and it poses a great environmental impact on a global scale. The most common methods for identifying the extent of saline water ingress in coastal aquifers are through periodic analysis of groundwater chemistry. The present study deals with the assessment of groundwater quality and vulnerability caused by the sea water intrusion and its remediation measures through the assessment of groundwater recharge potential zones. The present study was carried out in five phases. The groundwater samples were collected in the pre monsoon and post monsoon season. The hydrochemical characteristic of coastal aquifers in Thoothkudi, Tamil Nadu, seems to be influenced by various processes together with seawater mixing, anthropogenic contamination, and water rock interaction, as indicated by very wide ranges and high standard deviations of most hydrochemical parameters, such as TDS, Cland#8722;, SO2and#8722; 4 , Mg2+, and Na+ exceeding the limit of drinking water standard (WHO 1984). An integrated groundwater quality map of the study area was prepared using GIS. This integrated groundwater quality map helps us to know the existing groundwater condition of the study area. Principal component analysis (PCA) of the chemical variables of groundwater is employed to interpret the relationships with specific processes that control the quality of water. PCA was applied on 46 groundwater data sets to identify the latent factors that influence the variation of groundwater quality in Thoothukudi. Total hardness (TH) ranges from 138 to 2641 mg/l with an average value of 792 mg/l during PRM. newline