Reducing the Vulnerability of Societies to Water Related Risks at the Basin Scale (Proceedings of the third International Symposium on Integrated Water Resources Management, Bochum, Germany, September 2006). IAHS Publ. 317, 2007, 337–341.

Operational flood risk management based on ensemble predictions

JÖRG DIETRICH, FRANK VOSS & ANDREAS SCHUMANN

Institute of Hydrology, Water Resources Management and Environmental Engineering, Ruhr University Bochum, D-44780 Bochum, Germany

joerg.dietrich@rub.de

Abstract Flood forecasts are essential to issue reliable flood warnings and to initiate flood control measures on time. However, these forecasts comprise different uncertainties. Ensemble forecasts are means of describing different scenarios of the potential future development assuming different initial conditions, different model physics, or even different models. Hence they contribute to the estimation of the hydro-meteorological forecast uncertainty. This paper presents a methodology that is designed to support decision makers in issuing flood alerts, which are based on a probabilistic evaluation of flood forecast ensembles. First results from a case study at the mountainous Mulde catchment are shown using COSMO-LEPS meteorological ensemble forecasts for the extreme flood event in 2002. The rainfall–runoff model ArcEGMO was used to simulate discharge forecast ensembles.

Key words ensemble forecasting; flood management; hydrological modelling; risk assessment