A model is traced to evaluate and enumerate the significance of vulnerability
to seawater intrusion due to excessive ground water withdrawals and some anthropogenic
activities at coastal aquifers. So taking these issues into account few thematic
maps which were influencing the saline water intrusion were prepared and overlaid
using Geographical Information Systems (GIS). Based on GALDIT method, the groundwater
vulnerability cartography has been assessed. To reckon the GALDIT index it requires
six parameters like aquifer type, aquifer hydraulic conductivity, depth to groundwater
level (AMSL), distance from the shore, impact of existing status of seawater intrusion
and thickness of the aquifer. This GALDIT is the indicator scores and summing them
and dividing by the total weight for determining the relative role of each one.
Apart from this an identification of saltwater intruded area is done by using indicators
of saltwater intrusion like Cl/(HCO3 + CO3) ratio and Na/Cl
ratio. The vulnerability areas are classified as moderate with an area of 147.31
sq. km
and low covering an area of 168.72 sq. km respectively based on the thematic maps. The final
thematic map can be used for management of the coastal ground water resources.
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