A scenario-incorporating analysis of the propagation of uncertainty to flash flood simulations

► We propose a methodology to study the propagation of uncertainty in hydrological modeling. ► We examine the uncertainty from rainfall and model parameter estimation. ► We propose an approach that consider the variability of antecedent moisture conditions in the catchment. ► Interaction of sources of uncertainty produces an amplification effect in the results. This study proposes a methodology to analyze the propagation of uncertainty arising from radar rainfall and model parameter estimation to the flow simulations obtained from flash flood modeling. For this purpose an ensemble approach that describes the error from radar rainfall estimation and a novel approach that considers the seasonality and variability of catchment conditions in the estimation of model parameters have been implemented. The methodology analyzes the separate effect of each source of uncertainty and their interaction on runoff simulations. The methodology has been applied in the Besòs river basin, Catalonia (Spain) with a drainage area of 1020km2. The results show that the effect of parameter estimation uncertainty produces a smaller spread in the model realizations than the effect caused by the uncertainty in rainfall estimation.