Influence of rainfall spatial variability on hydrological modelling: study by simulations

This work presents a simulation chain which enables studying the significance of rainfall spatial variability on flood runoff. A turning-band-method rainfall generator is used to simulate rainfall fields of different space–time variability. Catchments are extracted from Diffusion-Limited Aggregation structures. Three different rainfall–runoff models are implemented and the Hayami function is used to propagate runoff. Two spatial rainfall resolutions are taken into account: 250 m × 250 m and the rainfall average over the catchment. In this context hydrological studies are carried out. The influence of size of the catchment, of its production function and its response time are analysed. Hydrographs are compared in order to determine the interest for hydrology of detailed knowledge of rainfall. This work is currently ongoing.