Tramblay Yves auteur aut IRD Bouvier Christophe auteur aut IRD Ayral P.A. auteur aut IRD Marchandise A. auteur aut IRD text journalArticle eng text/pdf born digital access A good knowledge of rainfall is essential for hydrological operational purposes such as flood forecasting. The objective of this paper was to analyze, on a relatively large sample of flood events, how rainfall-runoff modeling using an event-based model can be sensitive to the use of spatial rainfall compared to mean areal rainfall over the watershed. This comparison was based not only on the model's efficiency in reproducing the flood events but also through the estimation of the initial conditions by the model, using different rainfall inputs. The initial conditions of soil moisture are indeed a key factor for flood modeling in the Mediterranean region. In order to provide a soil moisture index that could be related to the initial condition of the model, the soil moisture output of the Safran-Isba-Modcou (SIM) model developed by Meteo-France was used. This study was done in the Gardon catchment (545 km(2)) in South France, using uniform or spatial rainfall data derived from rain gauge and radar for 16 flood events. The event-based model considered combines the SCS runoff production model and the Lag and Route routing model. Results show that spatial rainfall increases the efficiency of the model. The advantage of using spatial rainfall is marked for some of the largest flood events. In addition, the relationship between the model's initial condition and the external predictor of soil moisture provided by the SIM model is better when using spatial rainfall, in particular when using spatial radar data with R-2 values increasing from 0.61 to 0.72. specialized 062 11 1 157-170 2011 1561-8633 https://www.documentation.ird.fr/hor/fdi:010053465 10.5194/nhess-11-157-2011; 10.5194/nhess-12-267-2012 1561-8633 [F B010053465] https://www.documentation.ird.fr/hor/fdi:010053465 https://www.documentation.ird.fr/intranet/publi/2011/04/010053465.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2011-05-02 2021-01-24 fdi:010053465 fre