Abstract
An important step towards the protection of groundwater resources from potentially polluting activities involves the proper delineation of well head protection areas (WHPAs) for public water supply wells. Currently, common practice for the delineation of WHPAs in Greece is to use a simple fixed radius around the well, a method that can lead to significant overestimation or underestimation of the protection areas. In this work, the delineation of WHPAs in the basin of the Keritis River, located near the city of Chania, Crete, Greece is performed using a more accurate method that utilizes a decision support modeling tool called Wellhead Analytical Element Model (WhAEM). The unique hydrogeology of the modeled area (location of local heterogeneities, discontinuities, rivers, recharge, no-flow boundaries) is taken into account in order to define the well capture zones that need to be protected, to prevent potentially harmful contaminants reaching the water supply. The two main contamination threats in the region are olive oil producing facilities and cemeteries. Three scenarios were modeled corresponding to wet, dry and annually averaged conditions. The results show that during the summer period, when the aquifer of interest is heavily exploited, two wells are potentially threatened by olive oil production activities, one located in the southern part of the study area and the other in the center of the study area. A lesser threat was found for three other wells, due to potential contamination by cemeteries. For the winter and annually averaged scenarios, the protection zones were found to be smaller. Given that the priority is to protect the aquifer from threats with the least negative impact to the community possible, the results of this work can be taken into consideration by local authorities in their effort to protect the valuable water resources of the region and by legislators when updating current legislation on well head protection programs for the country.