Validation of FEST-WB, a continuous water balance distributed model for flood simulation    

The distributed event based hydrological model FEST, that adopts the classical SCS-CN method for abstractions, was extended for continuous simulation. The new FEST-WB model makes use of a simplified local water and energy balance scheme, accounting for soil, vegetation and atmosphere interactions, to provide Antecedent Moisture Condition (AMC) at rainfall beginning. In this work, particular care is focused on the understanding of the role that the AMC of soil plays in the run-off formation and on the flood hydrograph definition. The use of the FEST-WB model is analysed and the comparison between the two approaches showed that the ‘water balance ’ approach, while needing calibration, gets more reliable showing that the simple estimation methods (based on antecedent precipitation) adopted in event-based simulations often proved to be inadequate. The distributed event based hydrological model FEST, that adopts the classical SCS-CN method for abstractions, was extended for continuous simulation. The new FEST-WB model makes use of a simplified local water and energy balance scheme, accounting for soil, vegetation and atmosphere interactions, to provide Antecedent Moisture Condition (AMC) at rainfall beginning. In this work, particular care is focused on the understanding of the role that the AMC of soil plays in the run-off formation and on the flood hydrograph definition. The use of the FEST-WB model is analysed and the comparison between the two approaches showed that the ‘water balance ’ approach, while needing calibration, gets more reliable showing that the simple estimation methods (based on antecedent precipitation) adopted in event-based simulations often proved to be inadequate.