Perspectives section : The relational system for auditing the hydromorphology of rivers (SYRAH-CE): a multi-scale decision support tool for river management

Abstract

Following the request of the Ministry of Ecology, Sustainable Development and Planning and the Water Agencies to implement appropriate measures to achieve the objectives set by the Water Framework Directive, Cemagref was commissioned in 2006 to develop a system to assess the level of alteration of hydromorphological processes in watercourses. The "good ecological status", a common objective assigned to all water bodies by the directive, is based on an evaluation of biological compartments (fish, macro-invertebrates, macrophytes, diatoms) and certain chemical parameters. The physical characteristics of the watercourses, only mentioned to qualify the "very good ecological status", are taken into account in an indirect way, by their incidence on the quality of the habitats of the aquatic biocenoses, themselves likely to influence the biological status. The objective was therefore to have a tool for the hydromorphological characterization of the environments and to assist in the diagnosis for future restoration policies.