ABSTRACT
The contamination of groundwater from point and non-point sources of pollution is one of the sensations of development countries such as Iran. The Dezful plain located in North of Khozestan, South West of Iran is under the rapidly growth in industrial, agricultural and urbanization. However the study area is under agricultural, where the farmers used heavy pesticide. The main sources of supply water for the area are river and groundwater. The management of groundwater especially, the vulnerability of Dezful plain is very important. This study presents the application and estimation of aquifer vulnerability by applying the DRASTIC model using Geographical Information System (GIS).
The DRASTIC model uses seven environmental parameters (Depth to groundwater, net Recharge, Aquifer media, Soil media, Topography, Impact of vadose zone, and hydraulic Conductivity) to characterize the hydrogeological setting and evaluate aquifer vulnerability.
To validate the results of vulnerability map, sample of several water quality such as EC, TDS, PH, nitrates, nitrites and ammonia of study area's wells collected for two seasons, dry and wet. Based on results of DRASTIC model for the study area the North, North West and South West of the Dezful aquifer was dominated by High vulnerability classes while the other parts were characterized by low vulnerability classes. The high values of nitrates occurs and corresponding with high and moderate vulnerability class locations, however some parts of the high nitrate area corresponding to landfill location.
For the vulnerability zone assessment, based on resulted from the GIS interpretation and the high regional development consideration of the Dezful plain it is recommended that for area of high risk, pollution from agricultural lands should be under high attention, especially the contamination caused by pesticide on agricultural land should be limited.
In addition a conceptual groundwater model by using MODFLOW is underway to determine the flow and contamination movement of the Dezful aquifer.
