ABSTRACT. – In order to study Mediterranean coastal water management, a pluridisciplinary approach is developed. Reservoir geology and some of its tools, used in oil prospecting, are applied to build a detailed sedimentary model. The analysis of depositional environments and sedimentary process allows the correlation of pre-existing data (outcrop, borehole, and seismic profile) using Genetic stratigraphy (onshore domain) and seismic stratigraphy (offshore domain). The interpretation results in a better knowledge of the sedimentary geometries following correlations between onshore and offshore domains. It is thus possible to differentiate the coastal groundwater aquifers precisely and to establish their relative connections. At the same time, hydrogeological investigations such as hydrochemistry and geophysical prospecting allow us to elaborate the hydrogeological conceptual model of the case studies. Variable-density flow and solute transport simulations constitute the hydrogeological work. Experimental economy constitutes the third part of this integrated methodology. It assesses the effectiveness of institutional arrangements to cope with aquifer overexploitation. Feed-back from these three fields of research will also authenticate our methodology. This approach applied on Roussillon basin (south-west of the French Mediterranean coastline) could be exported to many other coastal areas.