Assessment of groundwater vulnerability to contamination: a case study

Groundwater is a globally important, valuable resource for human life and economic development. Despite its importance, it is often misused and rarely well managed. Delineation of polluted zone attains significance especially when the pollution affects the human health. Delineation can be done by many approaches: process based, statistical and overlay and index methods. Overlay and index methods are relatively simpler and are based on hydrogeological settings and other factors which are considered to control the groundwater quality in a region. Groundwater vulnerability to contamination due to anthropogenic as well as seawater intrusion in an unconfined aquifer spread over the watershed areas of Kazhakkoottam, Kulathoor and Menamkulam regions of Thiruvananthapuram District, Kerala, India, was carried out using both susceptibility index (SI) method and modified GALDIT index method. Majority of the region selected was categorised as moderately vulnerable by both indices. The cause of groundwater vulnerability to contamination was found using factor analysis. The factor score map of the study area also shows that majority of the study area is moderately affected by contamination. Hence, the area requires continuous monitoring of groundwater quality to prevent the contamination of groundwater resources for future generations.