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 pr incipal aim of modelling the Olocenic alluvial aquifer of the River Cornia coastal plain (southern Tuscany, Italy), which has been exploited for drink ing water, irrigation, and industrial uses. A consequence of exploitation h as been the appearance of wide seawater intrusion. The alluvial aquifer has recently been subjected to new well fields for the supply of drinking wate r, with an increase of total average discharge of about 4 X 10(6) m(3)/year . This paper presents results obtained from updating and integrating basic knowledge and structuring the database. The hydrogeological study allowed t he recognition of the extension of areas that are characterized by a hydrau lic head under the sea level, the progressive salinization of the aquifer, and the increase of water deficit in the aquifer which is produced by a pro gressive extraction of water superior to the natural recharge. In addition, benefits and disadvantages resulting from the location of new well fields in a hydrogeologically favourable zone, and the boundary conditions for muc h of the area studied have been defined. The GIS was used as support for ma king and updating the tabular and spatial database with the aim of integrat ing the local and regional hydrogeological knowledge. This study will permi t 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.