Open-channel inflows into lakes and reservoirs are vectors of momentum, sediments, nutrients, oxygen, heat and anthropogenic contamination. The spreading and mixing of the introduced quantities control the water quality, which is of paramount importance for drinking water supply, beach water quality, and fisheries. The inflow of sediments leads to reservoir sedimentation and underwater avalanches that threaten infrastructure. Negatively buoyant inflows plunge under the lighter surface waters of the reservoir or lake. This plunging process is accompanied by intense mixing, and conditions the characteristics of the subsequent underflow along the bottom of the receiving water body. The density of the underflow changes during its propagation due to mixing with ambient water and exchanges of sediment with the bottom. When the underflow reaches its depth of neutral buoyancy, it lifts of the bottom and forms an intrusion. Insight in the plunging, underflow and intrusion processes is still incomplete.
I am setting up a research project that will combine field measurements, laboratory measurements, and numerical simulations. In the seminar, I will first introduce the topic and discuss the importance of some open questions related to hydro-morphological processes. I will then show some initial results from field measurements on the inflow of the Rhone River into Lake Geneva and numerical simulations.