Le comportement des petits bassins versants ruraux dans le contexte des crues et des inondations

Small rural catchment functionning in the framework of floods and rainfall-runoff events

INRA

Abstract

Small catchments play an important role in the genesis of flood and rainfall-runoff events in large catchments for many reasons, as the cumulated length of hydrologic networks of first and second order. Small catchments are characterised by a large spatial and temporal heterogeneity. These catchments are a key room to characterise the processes during rainfall-runoff events. Recent observations on research catchments show a complex image of the runoff, result of the mobilisation of the different reservoirs in the catchment. Initial conditions have an importance equal to the rainfall characteristics. Impacts of landuse/land cover and of anthropic structures, as agricultural drains, ditches, hedges, are quickly addressed. Their effects are currently often modelised on simulated landscapes. These effects are quite limited on events with a low frequency. These processes characterise on a part of the hydrological hazard. Others studies at larger scale than small catchments and integrating the flux aggregation are needed. The control of the vulnerability is useful, but out of the scope of small rural catchments.