Olocenic alluvial aquifer of the River Cornia coastal plain (southern Tuscany, Italy): database design for groundwater management

Hydrogeological research is in progress, utilizing GIS methods, with the principaI aim of modelling the Olocenic alluvial aquifer of the River Cornia coastal plain (southern Tuscany, Italy), which has been exploited for drinking water, irrigation, and industriai uses. A consequence of exploitation has been the appearance of wide seawater intrusion. The alluvial aquifer has recently been subjected to new well fields for the supply of drinking water, with an increase of totaI average discharge of about 4X 106 m3/year. This paper presents results obtained from updating and integrating basic knowledge and structuring the database. The hydrogeologicaI study allowed the recognition of the extension of areas that are characterizedby a hydraulic head under the sea level, the progressive saIinization of the aquifer, and the increase of water deficit in the aquifer which is produced by a progressive extraction of water superior to the naturai recharge. In addition, benefits and disadvantages resulting from the location of new well fields in a hydrogeologically favourable zone, and the boundary conditions for mueh of the area studied have been defined. The GIS was used as support for making and updating the tabular and spatial database with the aim of integrating the local and regionaI hydrogeological knowledge. This study will permit the realization of a numerical simulation of the groundwater flow of the aquifer aimed at correcting the management of water resources, by means of the GIS-modelling integration.