Assessment of groundwater intrinsic vulnerability using GIS-based DRASTIC method in District Haripur, Khyber Pakhtunkhwa, Pakistan

The stress on the freshwater resources of the planet earth has led the United Nations to add a goal regarding clean water in sustainable development goals list in order to address the global availability of clean water. The widespread use of fertilizers and industrial effluents caused the groundwater contamination in the Haripur District, Khyber Pakhtunkhwa, Pakistan. To investigate and assess the vulnerability of groundwater to contamination, geographic information system (GIS)-based DRASTIC model has been employed. The DRASTIC index values lie between 88 and 190. The lower the DI value, the lower will be the susceptibility towards pollution and vice versa. The indices were classified into five zones, i.e., low (< 109), medium (110-129), moderate (130-149), high (150-169), and very high vulnerable zones (> 170) on the basis of equal intervals. The low vulnerable zone covers almost 6% of the study area, i.e., 118 km². Medium vulnerable zone encompasses an area of approximately 23%, i.e., 506 km². The moderate vulnerable zone is the largest in the district covering almost 965 km², approximately 45% of the study area. The high and very high vulnerable zone encompasses almost 23% and 3% of the study area which means 506 km² and 66 km² respectively. A spatial distribution map was generated for nitrate concentration to validate the DRASTIC indices. The results demonstrate a fair relation between groundwater susceptibility and spatial nitrate distribution. This index map will provide a baseline study for this area to develop the safe zones for groundwater exploitation and controlling the current state of deterioration of environmental norms. The areas of high vulnerability are the firsthand task to improve the current situation of crisis especially in the southern parts such as the Hattar industrial area and its surroundings drained by those effluents. These further need specific tasks to restore and reclaim the polluted ecosystem by using proper technological solutions for disposal of these effluents.