Advances in Operational Flood Risk Management in the Netherlands

Operational flood risk management refers to activities that aim to reduce the probability and/or negative consequences of flooding just prior to the expected flood event. An inherent feature of operational flood risk management is that outcomes of decisions taken are uncertain. The main goal of this study was to investigate and develop approaches to modelling dike failure probability and decision making in operational flood risk management in the Netherlands. In the study, the concept of operational dike failure probability was introduced. Such probability is derived using information referring to the flood danger at hand such as (i) probability forecasts for hydraulic loads and/or (ii) measurements of geo-hydrological processes inside and under dikes achieved with electronic dike sensors. Both concepts are relatively new in the Netherlands. Approaches to derivation of probability forecasts for dike loads were studied together with an economic appraisal of dike sensor systems. Two methods for derivation of operational dike failure probabilities were also considered. Furthermore, several (rational) models for decision making under uncertainty were developed. The operational dike failure probability is an input to these models. A basic decision problem was defined as the problem whether to apply an emergency flood measure facing an uncertainty flood event. The problem was adjusted in a number of ways e.g. postponing of the decision in time was studied. This decreases the effectiveness of the emergency flood measure however allows obtaining more reliable information about the upcoming flood event. Some of the developed models were applied to the preventive evacuation decision problem.Hydraulic EngineeringCivil Engineering and Geoscience