The Arve River is the most important tributary of the Rhone River The Arve has a very high sediment transport capacity due to its steep slope in the Alpine Valley. These solid materials deposit in the Rhone River. Because of the high sedimentation rate in the Verbois reservoir, the operator SIG (Services Industriels de Geneve) flushes the reservoir with complete drawdown every three years with major negative ecological impacts downstream. The aim of this study is to evaluate the feasibility of a bypass of the floods in the Arve River directly into Lake Geneva and therefore to reduce the sedimentation of the Verbois reservoir.