Landscape in mountain belts can be divided into "Catchments" or "Watersheds" : The area drained by a given river. Any water drop, falling in the catchment and flowing over the land surface would end in this river. Rivers are thus defined as converging flow paths.
In a catchment, one can distinguish two zones with regards to the mechanism driving erosion.
1) Hillslopes : Erosion is mainly driven by gravitational processes such as landsliding or creeping.
2) Rivers : Erosion is fluvial, that is to say driven by shear stress applied by the flow on the river bed.
© Patrick Meunier
