Critical Problems for the freshwater supply to summer resorts on the Eastern Coast of the Buenos Aires Province, Argentina
Since the middle of the twentieth century , the eastern coast of theBuenosAiresProvince, Argentina , has experienced a strong demographic growth that posed increasing requirements on the supply of freshwater. This was accompanied by a rather chaotic urbanization process and the expansion of human activities, particularly those related with the numerous summer resorts located there. In this region, the only natural source for the supply of freshwater to the inhabitants is the groundwater stored in lens-shaped reservoirs located in the coastal sandy barrier. With a mean hydraulic conductivity between IO and 20 mid, an effective porosity of more than I 0%, and a narrow thickness of the unsaturated zone (2-4 m), these reservoirs are highly vulnerable to pollution, pa11icularly from nitrates of anthropic origins (over 50 mg/L at some locations). In addition, an intensive exploitation of these aquifers can lead to a strongdrawdown, with the consequent threat of saltwater encroachment that will eventually force some production wells to be abandoned. This, in fact , has already happened. A suitable running of groundwater resources should thus take account of people's demand, an adequate freshwater supply, and the natural balance of thehydrologiccycle. Such management must consider the choice of new groundwater catchments and a land-use planning that includes the environmental protection of freshwater reserves. San ClementedelTuyu, one of the summer resort towns, is presented as a local sustainable case of groundwater management. Although the study area has general uniform geologic andgeomorphologiccharacteristics, there are, however,local differences. The resort towns located along the coast should therefore take account of these differences in designing their own groundwater management systems.