Transnational Modelling of the Meuse District by the Pegase Model

The environmental model, called PEGASE (Planification Et Gestion de l’ASsainissement des Eaux), is devoted to the characterization of the environmental state of surface water, from a local scale (a few km²) up to a of a global scale (internationals districts, hundreds of thousands km²). The model is able to simulate non stationary scenarios for entire river trees (hundreds to thousands of water bodies). The model is a tool to validate and check consistency of data at district (and thus international) level. The flexibility of the model enables to choose the time (daily to yearly periods) and spatial (watershed, water body, district, region, country…) scales of the expected results. In the context of the international coordination for the Water Framework Directive, the PEGASE model is used as a tool specifically addressed to simulate the IRBD (International River Basin District) Meuse. Indeed, the model: (i) is associated to a dedicated transnational database to apply the model to the entire district; (ii) is operational, the Meuse application has been calibrated and validated independently at this stage on most of regional sub-basins of the district; (iii) could be used to simulate –at that scale– historic and future scenarios to estimate water quality improvement that may be expected after applying basic and complementary measures