Aquifer vulnerability mapping using LANDSAT TM and SPOT images: The Malta mean sea level aquifer and the Manouba aquifer, Tunisia

The Hydro med Project, funded by CEC through the AVICENNE Programme, aimed to develop a computerized, standardized system allowing planners and administrators to determine the degree of vulnerability of an aquifer to various sources of pollution, from readily available data. In order to validate this method in the south mediterranean region, two test areas were selected, under comparable mediterranean climatic conditions, but offering very different hydrogeological features : the aquifer selected in Malta is of karstic character and connected to the sea, when the one in Tunisia is of alluvial origin. Land use mapping by means of two SPOT images in Tunisia, and one LANDS AT TM image in Malta, was helpful in improving and updating the existing heterogenous data, in delineating the different zones of the alluvial aquifer or the natural recharge areas for the karstic aquifer respectively, and allowed to put in evidence the extent of some of the most sensitive zones with regard to the pollution hazard.