Pollution risk assessment is an important task for sustainable management of groundwater resources. In this pilot study, we demarcated areas of different pollution vulnerabilities within the Vattamalaikarai River Basin (ca.435 km²) of south India using the DRASTIC index and involving the combined geospatial techniques of remote sensing, geographical information system and global positioning system. Seven major hydrogeological factors such as depth to water level, net recharge, aquifer media, soil characteristics, topography, impact of vadose zone and hydraulic conductivity, gathered from well inventory, were considered as variables in this model. Additionally, we took into account the rainfall, geology, digital elevation model (DEM) and borehole lithology data to understand the above variables. Our vulnerability map divided the study area into zones of ‘high’, ‘moderate’ and ‘low’ groundwater pollution risks. Most of the basin is under the moderate pollution risk, and the regions of “high” vulnerabilities are associated with the shallow and permeable aquifer formations. The partial validation of this modelling with respect to the spatial distribution of nitrate in groundwater suggests that studies similar to ours in other regions can provide quick information to decision makers for better groundwater resource management and protection.

污染风险评估是地下水资源可持续管理的重要任务。在这项初步研究中，我们划定了Vattamalaikarai流域（约435 km ^2）内不同污染脆弱性的区域印度南部）使用DRASTIC索引，并涉及遥感，地理信息系统和全球定位系统的组合地理空间技术。该模型考虑了七个主要水文地质因素，例如从水库中收集的水深，净补给量，含水层介质，土壤特性，地形，渗流带影响和水力传导率等因素。此外，我们考虑了降雨，地质，数字高程模型（DEM）和钻孔岩性数据，以了解上述变量。我们的脆弱性地图将研究区域划分为“高”，“中”和“低”地下水污染风险区域。流域的大部分地区处于中等污染风险之下，“高”脆弱性地区与浅层和可渗透的含水层形成有关。