Groundwater Vulnerability Mapping in Faisalabad District Using GIS Based Drastic Model

Abstract

The demand of groundwater has significantly increased during the past two decades to meet the food and fiber requirements due to constrained surface irrigation water. The groundwater has a major share to grow agriculture in Punjab-Pakistan, which produces more than 90% gains of the country. Beside the importance of groundwater, a major concern in recent years is the contamination of groundwater. The consecutive monitoring and mapping of aquifer water quality in large areas is a hectic job and not even economically feasible. Thus groundwater vulnerability maps are becoming more in demands to represents regional aquifer contamination potential. The aim of this research work was to find out the groundwater vulnerability potential zones in Faisalabad and its nearby areas, which is the fastest growing city of Pakistan. For this purpose, GIS based DRASTIC model was used to measure vulnerability related to agriculture in Faisalabad district. The inputs of the model are based on seven different layers. The results of the model were compared with groundwater samples. It was found that the DRASTIC model accurately identified the vulnerability of Faisalabad District with prediction efficiency of about 73%. The results revealed that more than 30% of study area was under high vulnerability potential. The areas under high vulnerable pollution are located in middle and upper part of Faisalabad District. The high vulnerable pollution in surrounding of Salarwala, Chak Jhumra and Khurianwala cities was due to shallow groundwater table, high recharge, gradual slope, sandy aquifer media and soil media consist of medium sand. The high vulnerable pollution in surrounding of Dijkot city was due to shallow groundwater table, gradual slope, vadose zone consist of course sand and high hydraulic conductivity. It is therefore recommended that Rainwater harvesting and ASR (Aquifer Storage and Recovery Wells) should be adopted in medium and high vulnerability areas to reduce water salinity.