ISOTOPE HYDROLOGY: MULTI-ISOTOPIC APPROACH IN COASTAL AQUIFERS AND THERMOMINERAL WATER SYSTEMS IN N PORTUGAL
Discrimination between seawater intrusion (anthropic actions) and minerals dissolution (natural salinization) were the main goals of part of the investigations carried out during 2017. Studies on the impact of groundwater over exploitation in coastal areas were carried out in Algarve and at Lower Sado basin (Portugal) and in Morocco W Atlantic coast Essaouira basin. The major results obtained include: (i) evidences of mixing with ancient seawater trapped in the sediments during the Sado basin formation; (ii) evaporitic minerals dissolution at Tavira (Portugal), Essaouira (Morocco); and, active seawater mechanisms at Portimão/Faro. The study of thermomineral waters continued in the N part of Portugal, with the main objective of definition of conceptual circulation models in several aquifer systems, being the delimitation of the preferential recharge areas and evaluation of the mean residence time the main goals, to achieve a proper management and protection of this type of water resources.