Evaluation of intrinsic vulnerability, hazard and risk mapping for karst aquifers, Khorein aquifer, Kermanshah province: a case study

The Khorein karstic aquifer in the Kermanshah province (western Iran) plays a vital role in providing drinking and agricultural water for its surrounding communities. The aim of this research is to evaluate natural vulnerability, hazard and risk indices of the Khorein aquifer by cost action 620 proposed models, as well as to prioritize the aquifer surface concerning to protection measures and providing management strategies in order to its better protection. The results of the COP method represent the high natural vulnerability of the region. Calculation of the hazard index show that the military regions, telecom sites, the nomads’ habitation areas and quarries are situated in areas with low hazard index. Evaluation of the risk index and predict the aquifer contamination show that 75 % of the region extent is no or very low contamination risk, which this is due to low development of human activities in the top of the mass. This claim is confirmed by the presence of Escherichia coli bacteria in the aquifer water. The expansion of human activities in future toward the altitudes, can lead to further pollution of the aquifer. Continuous monitoring of the chemical characteristics of water, taking the recharge map, characterizing the areas with concentrated charge, determining the karstic landform limits, restricting the livestock activities on the anticline top, avoiding the construction activities close to the aquifer and improving the people and authorities public awareness level are the main necessary measures pertaining to manage the Khorein aquifer.