Assimilation of soil moisture in a hydrological model for flood forecasting

This paper introduces a parameter updating procedure of the "variational" type that can be combined with any conceptual rainfall-runoff model for flood forecasting purposes. The main feature of this method is that it carries out updating by reference not only to recent streamflow observations, as do classic procedures, but also to soil moisture measurements, which can be retrieved either from TDR probes or from satellite remote sensing systems. The aim of the research was to assess the usefulness of this additional soil moisture information. The application of this new methodology has been carried out on a sub-basin of the River Seine at Paris. The first results are presented and, for this sub-basin, soil moisture seems not to be very useful to increase the efficiency of the updating procedure. But, due to the reduced number of recorded flood events, no definite conclusion can be reached.