Comparison Between Hydrodynamic Simulation and Available Data in a Karst Coastal Aquifer: The Case of Almyros Spring, Crete Island, Greece

Abstract

The Almyros spring is the outlet of the largest karst coastal aquifer in Crete Island, Greece. The spring is important for drinking water supply of Heraklion, the capital city of Crete. However, because of sea water intrusion, most of the time and especially during the dry season, the water is brackish. Since the 1960s, despite repeated efforts to collect the freshwater resources of the aquifer, only few practical results have been obtained. In order to investigate alternative measures for collecting the aquifer’s freshwater a mathematical model was developed for simulating the saturated groundwater flow in the karst porous medium. Although the local use of the Darcy’s law for flow simulation in discontinuous porous media such as karst aquifers is problematic, it can give useful results when applied in larger scales. For studying the hydrodynamic characteristics of the Almyros/Heraklion aquifer, the numerical model MODFLOW was used and after calibration, it is shown that useful results can be obtained in practice.