Riverbeds play an important role regarding sediment transportation
to the outlet, demonstrating specific hydrological and
erosive characteristics. To account for these processes, the drainage
network was extracted from the DEM, and it was considered to be
infiltrating but not eroding for two reasons. The first one is that the
scaling of plot measurements to the watershed level and their
comparison with outlet measurements showed that the annual
sediment delivery ratio (SDR) was close to one (Cheggour, 2008).
The second reason is that visual observations of the riverbeds
showed that they were mainly stony with no evidence of significant
bank erosion or deposition areas over the long term. Some temporary
deposits were locally visible in flat areas of the riverbeds,
but they were likely to be removed during subsequent flood events
and would not accumulate over the long term.