Abstract

One important approach in the management of karst water resources is mapping of karstic aquifers. Vulnerability mapping enables identification of the groundwater resources that are subjected to contamination. The Gilangharb karst aquifer as part of the folded Zagros zone feeds the Gilangharb karstic aquifer. Field visits and examination of chemical properties of the Gilangharb spring all confirm the karstic nature of the study area. In this study, in order to evaluate the vulnerability of the Gilangharb karstic aquifer, the EPIK method consisting of four layers of E (epikarst), P (protective coating), I (penetration) and K (karst network) and also the KDI method based on land use were employed. The former method is one of the inherent vulnerability methods developed especially for the karst areas based on different weight and ranking parameters. After executing the model and preparing the vulnerability map, the EPIK index was calculated between 12 and 26. The spatial distribution of the final vulnerability map classes from the EPIK model shows that 14.24, 14.56, 47.17 and 24.03% of the study area, is located in the low, medium, high and very high vulnerability zones, respectively. According to this map, about 71% of the study area shows high and very high vulnerability indicating high vulnerability of this aquifer. According to the results of the KDI method, 7.54%, 9.49%, 2.9%, 77.89% and 2.18% of the study area had high, medium, low, very low and intact, respectively that shows low vulnerability of the Gilangharb karstic aquifer.