Igor Lisac, GFZ German Research Centre for Geosciences, Earth Surface Process Modelling, Potsdam, Germany, Jean Braun, Universite Joseph Fourier, Grenoble, France, Niels Hovius, Helmholtz Centre, German Research Centre for Geosciences (GFZ), Potsdam, Germany and Eric Deal, Massachusetts Institute of Technology, Department of Earth, Atmospheric and Planetary Sciences, Cambridge, MA, United States