SEDMIX: Controlled routing of fine sediment from storage reservoirs with a hydrodynamic mixing device

Reservoir sedimentation is, at present, one of the main issues in the operational management and sustainable operations of hydropower plants in the Alps. The construction of a dam alters the sediment inflow and outflow balance that can be observed for natural conditions and the continuity of the sediment flow is interrupted, resulting in sedimentation. The filling up of reservoirs has negative impacts on hydropower production and leads to several problems, such as reduction of live storage, blockage of power intakes, turbine abrasion or dam safety in case of blockage of bottom outlet. The SEDMIX device is composed of two parts: one floating and one close to the basin bottom holding a multi-thruster manifold frame. The thrusters induce a rotational flow which creates an upward motion and keeps fine sediments in suspension near the dam and water intakes. The efficiency of the SEDMIX device has been validated through experimental and numerical simulations at EPFL PL-LCH. Although experimental studies have shown the effectiveness of this system, its performance has not been tested in site-specific reservoir conditions, or at full-scale. This project will install, test, operate, and optimize a real-size demonstrator that includes the SEDMIX device, the command and monitoring facilities, and the detailed protocols for implementation, operation and relocation.