Design a Relational System for Auditing the Hydromorphology of Waterbodies (SYRAH_CE)

Abstract

We have entirely designed de novo a Relational System for Auditing the Hydromorphology of Waterbodies (SYRAH_CE), to respond to the new ambition in 2000 to introduce hydrology and geomorphology within the process of establishing the WFD status reports. The work was carried out at a time of technological transition in terms of cartographic tools, since the Institut Géographique National (IGN) was beginning to market digitized geographic information layers. We made two strong choices, the first one to use a selection of these digitized data in order to build a homogeneous system on the scale of the whole national territory, operable with a Geographic Information System (GIS), the second one to propose an analysis system centered on the structure and the functioning of the morphology of the waterbodies guaranteeing in particular the supply and the maintenance of aquatic habitats of quality. Finally, the whole system is based on the identification at different scales of pressures and uses likely to alter this physical functioning. It differs in this respect from approaches in geomorphology or ecology, which are based on the evaluation of deviations from reference situations. The approach has been adopted by the operational community and is now an integral part of the methods deployed in each WFD assessment cycle since 2012. It is also used as an aid to prioritize actions for physical restoration of waterways.