53-Seawater Intrusion into Coastal Aquifer - A Case Study from Puri District, Orissa.

Abstract

About sixty percent of the world population live within a distance of less than 60 km. from the coastline, wherein groundwater is the most important source of freshwater. The quality of groundwater in coastal aquifers is threatened by various human activities like irrigation, industrialisation, urbanisation, tourism etc. Besides, this valuable resource is susceptible to seawater intrusion with the ever increasing development of groundwater. Recently, the 'variable-density 3D transient groundwater flow modeling' has been successfully employed worldwide in order to simulate, assess, predict and manage the process of seawater intrusion. A case study in a coastal tract (1834 km2) having a shoreline length of 60.5 km. adjoining Bay of Bengal in Puri district of Orissa has been carried out using SEAWAT-2000 for an optimal management of seawater intrusion. SEAWAT solves the coupled groundwater flow and solute-transport equations through finite difference method. The model simulation shows that the seawater ingress occurs at the semi-confined aquifer of Layer 6 (120-180 mbgl) and Layer 8 (200- 240 mbgl). This model can be used for a reasonable representation of a multilayered coastal aquifer system to simulate the three dimensional distribution of groundwater salinity in the regional context of Puri. Moreover, the model can be used as a suitable tool for giving complex groundwater management options in coastal belt of Pun with an input of adequate field data through further calibration and refinement.