this aquifer is shared by france and switzerland and a joint agreement for its management and protection was first signed in other jointly agreed transboundary aquifers include for example those shared by belgium and the netherlands belgium and france austria and hungary austria and slovenia and spain and portugal for instance on the basis of hydrogeological knowledge ecological criteria and the presence of natura sites groundwater bodies in the scheldt river basin were identified as being in close connection with surface water however even for the wellestablished river basin commissions addressing transboundary groundwaters is a new challenge