The project concerns the preparation of four specific hydrogeological studies provided for in the Management Plans for the drainage basins of the Ionian Islands in order to define and precisely demarcate the areas of the coastal underground water bodies of the four major Ionian islands which, according to the 1st Revision of the RBMPs, show phenomena of extensive or local brackish contamination regardless of their origin; to define the brackish mechanism, distinguishing between the one due to natural causes and the one resulting from anthropogenic activity; and c to define the measures to limit or reverse sea penetration, particularly in cases where it is due to human activity.