How to integrate scientific models in order to switch from flood control river management to multifunctional river management?

Abstract : Since 2000, the European Water Framework Directive has required managers to restore water bodies to good ecological status, including rivers that have been substantially anthropomorphized, i.e. the vast majority of rivers in France. This obligation creates situations, such as removal of mill sluice gates and strong resistance from local stakeholders that must be addressed by governmental agencies and local elected officials. Seine watershed researchers have suggested using a hydraulic model to give river managers an overall vision of structure function (including sluice gates) and the water elevation adjustments between the upstream and downstream reaches with adjustments to the structures. Scientists adapted their model with the collaboration of the local actors in charge of the river management. This simulation of the management of river structures was achieved by constructing an interactive platform and using it to simulate annual flow scenarios for the river and management objective scenarios for all types of use, both recreational and high- and low-water scenarios. Model construction and simulation reunited scientists; State services agents, elected officials but also mill owners and members of local associations. The objective of this collective use was to allow managers to appreciate the current knowledge on the effects that removing a structure would have, around a multifunctional approach to the river, to consider removal of certain structures depending on the locally expected results.