Perspectives offertes par la communication entre un modèle hydrodynamique et un SIG pour l'aide au diagnostic environnemental : caractérisation de la dynamique et la qualité des masses d'eaux côtières.

This paper presents a set of solutions based on the synergy between GIS and a numerical model to help in diagnosis and decision making for water quality related matters. After an overview of the model features, it describes the computer interface (ModelView) implemented as an extension of the Arc View (ESRI) GIS System to provide operational data communication between the model and the GIS in vector or raster form. The paper particularly focuses on changes in the quality of coastal waters from river discharges. It looks at the spatio-temporal representation of this behaviour and the spatial analysis of sensitive areas that can be impacted. Examples are given of a French coastal area subject to strong human pressure, i.e. marine cultures and recreational activities that are directIy dependent on coastal water quality. The interest in establishing synergy between numerical models and GIS is discussed in the conclusion, based on the specific situations given as examples. Prospective development of general geographic databases providing representative coastal are a hydrodynamics synthesis fordecision making support is also examined.