ABSTRACT
The subsurface aquifer systems in Mahanadi delta region in Orissa (India) is largely characterized by two groups of freshwater aquifer systems: 1. The south western Mahanadi delta region is represented by unconfined to semi-confined freshwater aquifers underlained by brackish/ saline aquifer systems with a diffusion boundary 2. The north eastern parts of Mahanadi delta is represented by deep freshwater confined aquifers overlained by brackish/saline water aquifers with aquitard/ aquiclude boundary. Both the systems are prone to saline water mixing/ migration with time and development. The present paper incorporates results of a simulation study using a finite element based FEFLOW model and examines saline water migration scenarios when subjected to increasing rates of pumping under steady state conditions with the help of a calibrated groundwater model. The results indicate the unconfined and semi-confined aquifer systems in the south western part of Mahanadi delta are prone for faster rates of saline water mixing of the contamination when compared to the deep confined systems in the north eastern parts of Mahanadi delta.