Peak flow estimation under parameter uncertainty in a real-time flood warning system for ungauged basins

摘要

An operational flood forecasting system designed to produce peak flow predictions at multiple ungauged sites is described. The system is based on the ensemble approach and uses a simple conceptual rainfall-runoff model. This paper accounts only for parameter uncertainty; to this end, parameter sampling distributions with Monte Carlo generated simulations are related to basin geomorphic characteristics and event antecedent moisture conditions. Application to four gauged sites exhibited satisfactory system performance in terms of reproducing observed peak flows Further assessment evaluated the system's forecasting skill with a back-analysis performed on 40 ungauged basins over the period 2002-2005,, Results showed that the system yielded a reasonable number of warnings and that all the selected floods events, characterized by high documented social impacts, were successfully detected.