Hydrological modelling of the Saone basin sensitivity to the soil model

In the framework of the GEWEX / Rhone project, which aims at developing a regional model of the surface energy and water cycle in the Rhone basin, the flow of the Saone river basin (30000) km2 was modelled with the MARTHE model. The paper first describes the functionalities of MARTHE and then the modelling of the Saone basin with a 2 km grid at a daily time step over a 14 years (August 1981 to July 1995) using different surface hydrological models (soil models) : these soil models require from 3 to 91 parameters over the entire basin. A comparison of the results shows that the daily flows at the 52 gauging stations of the Saone are best modelled with the GR4 soil model using only 3 parameters. This advocates the gathering of additional data namely aquifer data and soil saturation in order to avoid over-parameterisation.