To sample or not to sample: IHE Delft students wading a freezing mountain gravel bed river

Every year we take IHE Delft students to carry out a 2 weeks long field work in Southern France: can you spot them in this drone aerial photography?
When water level are safe to wade along the Bes River, they measure water discharge and bathymetry of this mountain gravel-bed river.
Before the field work they learn how to check the quality of hydrological data and how to analyze them.
During the field work they experience also the practical sides of data collection and they face the challenges that this imply first hand.
Despite the efforts needed, this is one of the most valued course by the students, at IHE Delft