Hydrogeological characterization of the Asmari limestone aquifer, Anar anticline, Zagros Region, Iran

The Anar anticline is located in the Zagros Region, south of Iran. The anticline comprises of the Asmari Formation which is sandwiched between two impermeable formations, the Pabdeh-Gurpi Formation at the bottom and the Gachsaran Formation at the top. There are several freshwater resources (e.g., spring, lake, qanat, and pumping wells) around this anticline without clear known hydrogeological connection of which to the Anar anticline. The comprehensive hydrogeological studies, including the use of the APLIS method, karst hydrogeology, hydrochemistry, and stable isotopes data of the lakes and surrounding springs, were carried out in the study area. Results show that the anticline has no hydrogeological connection with the Haft Barm Lakes, but hydrogeologically, there is potential for hydraulic connection with the Chehel Cheshmeh Spring. The study shows that the catchment area of the Mashayekh and Deh Gerdoo Springs is located in the northeast and a part of the southwest flank of the Anar anticline. Mean annual recharge rate in the Asmari limestone aquifer is estimated less that 38.5 % based on the APLIS approach that confirmed by water balance.