1. Hydraulic Engineer, ETH Zurich, CH-8092, Zurich, Switzerland (corresponding author).
2. Professor, Laboratory of Hydraulics, Hydrology and Glaciology, ETH Zurich, CH-8092, Zurich, Switzerland.
3. Professor and Director, Laboratory of Hydraulics, Hydrology and Glaciology, ETH Zurich, CH-8092, Zurich, Switzerland.