Evaluation of Groundwater Vulnerability to Contamination in Coimbatore District

Abstract

Groundwater usage in the world is widely reported to increase because of the uncertainties attached with the availability of surface water. Groundwater resources are looked upon as the alternate source of freshwater on account of its widespread and continuous availability in proximity to the point of use or living place, less vulnerability to contamination and low cost of extraction in both urban and rural area of developed and developing countries of the world. Such a scenario has led to the degradation and depletion of groundwater resources in many parts of the world. The study area, Coimbatore district, is a rapidly urbanizing and industrializing city in the southern part of India which relies upon the groundwater resources for meeting the agricultural, industrial and domestic requirements. In view of this evaluation of groundwater resources and an understanding of the vulnerability of the aquifer to contamination become essential for the effective management of groundwater resources. The vulnerability of the groundwater to contamination is assessed using DRASTIC and Pesticide DRASTIC index in the GIS environment. The study showed that the high vulnerability areas are characterized by shallow water table of less than 4 m, gentle topography, sandy loam soils, thinner vadose zone and underlying geologic formations with well-developed fissures and fractures.