Risk Assessment of Lowering of Groundwater Table Using GIS for the Qareh Aghaj Sub-Basin, Southern Iran

Entire land of Southern Iran faces problems arising out of various types of land degradation of which lowering of groundwater table forms an important feature. The Qareh Aghaj sub basin, which covers the upper reaches of Mond River, has been chosen for a test assessment of the consequences of lowering of groundwater table. The various kinds of data gathered from the records and published reports of the Ministries of Agriculture and Energy of Iran have been analyzed in the GIS mode. The paper attempts at evolving a model for assessing the risk of lowering of groundwater table by considering eleven indicators of the same. The risk is related more to the irrigation activity which has led to increasing the number of wells, and groundwater overexploitation during the recent years, but some natural causes like the fluctuation in annual rainfall and hydrogeological characteristics also played a role in the recharge dynamics of the aquifers. The GIS analysis has made it possible to distinguish the areas with potential risk' from those widespread areas that showed the 'actual risk' of lowering of water table. It helped also to identify the areas which should be chosen on priority basis for remedial measures to mitigate the impact of lowering of groundwater table.