Assessing Groundwater Vulnerability in Azraq Basin Area by a Modified DRASTIC Index

Abstract

Groundwater is the main source for water supply in Jordan. Surface water is limited due to low precipitation rates. Studying groundwater vulnerability helps to protect this main source of depletion and degradation for present and coming generations. Different vulnerability indices were built taking into consideration the different environmental setting of the different areas for which these indices were established. Environmental and weather conditions are very important factors in determination groundwater vulnerability hence arid to semi arid areas conditions must be taken into account in applying different indices. The reason after selecting Azraq as a rest point is related directly to the availability of fresh water resources in the form of the wetland supported by many potential springs making Azraq a rich environment for economic activities. A modified DRASTIC vulnerability index was applied to Azraq basin area due to its special climate and wetland area conditions. The index takes the special landuse and the different groundwater depths into consideration and suggests a few measures to alleviate the vulnerability of the groundwater resources due to overexploitation and human activities changing the value of landuse. Azraq basin represents four different vulnerability classes, ranging from Low to very high vulnerability class. The lower vulnerability class areas are distributed in theareas with high depth to water table and low recharge areas with low human activities. The higher vulnerability classes are shown in the areas with high possibility of the pollutants to reach the groundwater. The modified DRASTIC index added the value of the human activity and the structural features in the area which give a more ease to pollutant to permit the aquifer.