A method of multiple working hypotheses was applied to a range of catchments in the
Mediterranean area to analyse different types of possible flow dynamics in soils during
flash flood events. The distributed, process-oriented model, MARINE, was used to test
several representations of subsurface flows, including flows at depth in fractured
bedrock and flows through preferential pathways in macropores. Results showed the
contrasting performances of the submitted models, revealing different hydrological
behaviours among the catchment set. The benchmark study offered a characterisation
of the catchments' reactivity through the description of the hydrograph formation.
The quantification of the different flow processes (surface and intra-soil flows)
was consistent with the scarce in situ observations, but it remains uncertain as a
result of an equifinality issue. The spatial description of the simulated flows over
the catchments, made available by the model, enabled the identification of counterbalancing
effects between internal flow processes, including the compensation for the water
transit time in the hillslopes and in the drainage network. New insights are finally
proposed in the form of setting up strategic monitoring and calibration constraints.