Olivier Evrard is a research director at the French Atomic Energy Commission (CEA), University Paris-Saclay, France. He has a PhD in Geoscience (2008) from the University of Louvain, Belgium. His research is at the crossroads of soil science, hydrology and geomorphology, and his main research interests are associated with the quantification of sediment sources and dynamics in contrasted river catchments. To this end, he uses multiple tools including fallout radionuclides, geochemistry, colour, environmental DNA, etc.