New hybrid method to simulate discharges on ungaged catchments by combination of hydrological and hydraulic models

The estimation of discharges on ungauged basins is a central issue in hydrology and resulted in various modelling developments during the PUB decade. In this field, the potential of distributed and semi-distributed models is high considering their capacity to extract results on interior points of a catchment based on the calibration on downstream discharges. Unfortunately, recent attempts [Smith, 2004, Reed et al., 2004] proved disappointing when such models are compared to lumped ones on objective basis, revealing a paradoxical picture: spatial complexity integrated in distributed models may increase errors that lumped models can limit thanks to a compact structure.