Résumé
Agro-stresses on greater Punjab aquifer are rising because of unchecked growths of agriculture. Secondary salinity and pollution loads from non-point sources (NPS) are two environmental concerns of these growths. In order to assess the impacts of NPS pollution on underlying aquifer, a source-pathway-receptor model commonly refered to as DRASTIC is applied in a GIS environment. The model is applied by combining data sets that describe the depth to groundwater, recharge rates, aquifer material, soils composition, topography, vadose zone materials, and hydraulic conductivity. Resultant vulnerability values are scaled into three vulnerability zones based on DRASTIC Vulnerability Index as low, moderate and high vulnerability. A major portion of the study area about 1798 km squares (57.6%) fall under low vulnerability zone, while the porportions of the study area under moderate, and high vulnerabilities are 790 km2 (25.3%), and 551 km2 (17.6%), respectively. The vulnerability of Tehcil Kot Addu is related positively to the recharge rates and agricultural landuse. Results of this study can be used for sustainable agriculture in the study area and other regions having silmilar hydrogeological characteristics.