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long enough to allow for significant sediment exports outside the bypassed reach. Fresh sand deposits were observed on the channel banks after the releases, similarly to what it has been shown on the Colorado River [3]. Deposits were also been observed near the wetted channel and in some areas, vegetation has been covered with fines. Reducing the stock of fine sediments in the river has had a positive impact on water levels and therefore on the habitats available for aquatic fauna. 5. CONCLUSION The step-by-step design of water releases implemented in the Selves, even if it required considerable human and financial resources, has proven to be a worthwhile strategy. The flow rates were selected in an adequate range and through this process, the optimum flow rate for future operations was identified. We now know that a flow slightly less than or equal to 10 m3/s allows for a significant mobilization of the TSS and that a flow of 15 m3/s allows a much more significant mobilization of the sand fraction. In addition, even if the risk of mobilizing coarser sediments remains relatively low, the cost/benefit of using higher flows does not appear to be worth it. The morphological evolutions observed indicate that in rivers with a high sand load, even modest flows can achieve morphological changes in the active channel. From an environmental point of view, the various objectives were achieved. There was substantial evacuation of sand and silt in the bypassed section that even exceeded our expectations, thereby improving the quality of available spawning areas. Furthermore, at the upstream station, new habitats are available for aquatic fauna in relation to the increase in water level. REFERENCES [1] INGLE J.C.JR. The movement of beach sand : an analysis using fluorescent grains. Developments in Sedimentology. Elsevier Publishing Company, 1966, Nr. 5. [2] GROSPRETRE L. Etude et gestion des impacts hydrogéomorphologiques de la périurbanisation. L’exemple du bassin de l’Yzeron dans l’Ouest lyonnais. PhD thesis, 2011. [3] SCHMIDT J.C., PARNELL R.A., GRAMS P.E., HAZEL J.E., KAPLINSKI M.A., STEVENS L.E. and HOFFNAGLE T.L. The 1996 controlled flood in grand canyon: Flow, sediment transport, and geomorphic change. Ecological Applications, 11(3), 657–67. 2001. 380