Comparison of surface and interior karst development in Zagros Karst Aquifers, Southwest Iran

Aggressive recharge water is capable of widening the surface and interior openings of karstic layers that leads to the easy flowing of water in this type of aquifers.The object of this study is to understand if surface karstification is the same as the interior karst development of an aquifer.Surface karstification was analyzed using Geographic Information System and remote sensing techniques, while interior karstification was studied with spring hydrograph analysis.The study area includes seven carbonate aquifers in the Zagros Region of Iran.The surface karstification of these aquifers is controlled by different factors including the thickness of carbonate formations, distance from faults, fracture density, precipitation, temperature, vegetation index, slope, and relief.The most important factors are precipitation and presence and density of faults and fractures; while the least significant factor is the vegetation cover.The spring hydrograph analysis shows that there are different ways of estimating the relative karst development, but each parameter that impacts the specific character of the karst aquifer might be independent of others.Furthermore, comparing the relative surface and interior karst development demonstrates that the possible relationship between them is unpredictable.Consequently, we define a specific and unique numeric method to assess the interior karst development that permits a meaningful concept and comparison among different aquifers throughout the world.