Delineation of the Areas with Potential Land Subsidence Using the Analytic Network Process (Case Study: Birjand Aquifer, Iran)

Abstract

In arid regions, the shortage of water resources and a rapid population growth have damaged the natural balance and caused a sudden or gradual land subsidence. Therefore, in the future, even if there is water on the Earth’s surface, its potential downward penetration will be unlikely. Consequently, if these water spaces are lost, they will be lost permanently, which means the disappearance of aquifers. In this study, six criteria (hydrology, lithology, etc.) are used to determine the potential subsidence of land above the Birjand aquifer by the analytic network process. The method of collecting data is based on questionnaires and interviews with experts. The results show that the hydrogeological criterion and the subcriteria of water resources availability and groundwater exploitation play the most important role in determining potential ground subsidence. It has been found that approximately 14% of the aquifer is prone to subside in village of Dastgerd, the Masoumiyeh residential area, and the town of Khousf. According to the observational data on the influx of sewage to the aquifers below the residential areas, there has been a decrease in water availability that caused the breakdown of open-end wells with time. Therefore, greater focus should be placed on planning land utilization, especially concerning the residential areas that are prone to higher risk.