Modeling groundwater vulnerability using GIS

Modeling groundwater vulnerability using GIS

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Mr. S. Kumar
Doctoral student, Dept. of Civ. Engg., Anna Univ, Chennai-600025

Dr. K. Venugopal
Director, Inst of Remote Sensing, Anna Univ, Chennai-600025.

Abstract
This paper deals with developing a graphical represention of groundwater vulnerability to contamination using GIS for the Chennai basin. The Ultimate aim of this project is to protect human health by protecting groundwater supplies. There are two main methods of protecting the human population from unsafe groundwater:

  1. Prevent groundwater from contamination;
  2. Remediate contaminated soils and aquifers if contamination does occur.

Groundwater is often treated, significantly less than surface water, as it tends to be a cleaner source. This also means that if contamination occurs, it is more likely to have a negative effect on the population, as less steps are present to remove the contaminant before it reaches the public. A graphical representation of vulnerable aquifers, combined with graphical representations of potential sources of contamination and public water supplies would allow decision makers to evaluate current land use practices and make recommendations for changes in land use regulations which would better prevent the groundwater from contamination. For example, it may not be considered responsible to build a new chemical plant in the contributing area of a particularly vulnerable aquifer or area of an aquifer. Additionally, such a representation would provide a quick tool for determining possible responsible parties if contamination is found,thereby expediting the remediation process. Another potential benefit from mapping vulnerability is that it aids in the prioritization of remediation sites. Responsible parties must pay for the remediation of a polluted site, however in many cases the responsible party can not be found. In these cases the government pays for the remediation of the waste site. Unfortunately, there are so many such sites around the nation that they must be prioritized due to limited resources. A vulnerability map would aid in this prioritization.