Flood forecasting in the Anglian Region: User-driven development towards forecasting flood risk

Abstract

The Anglian Region of the Environment Agency of England and Wales has replaced a fragmented and in most places technically limited flood forecasting capability with a state of the art system (the Anglian Flow Forecast and Modelling System – AFFMS). This has created a platform from which to tackle issues of accuracy, reliability and timeliness and has expanded access to forecasts to a wide customer base. Perhaps most importantly, it will help flood event managers move from a relatively passive (monitoring) mindset, to a forecasting approach that considers “what will, or what might happen?” However, the demands upon flood forecasting are increasing beyond even this newly acquired capability This paper reviews the technical and organisational improvements achieved in the Anglian Region within the context of the traditional structure of forecast delivery. It then considers future challenges, proposing a development of this structure to a probabilistic or risk-based approach. This approach explicitly incorporates the limitations inherent in predicting flood events due to the natural variability and inherent uncertainty of hydrological systems. It develops the proactive forecasting mindset further to consider “how likely is a particular outcome?” and “what are the likely consequences?” It also provides a framework within which technical developments can be prioritised and expectations managed Although the specific circumstances of Anglian Region are unlikely to recur elsewhere, it seems likely that the need for risk forecasting will emerge elsewhere, at least within service-orientated societies. The paper therefore concludes that, if forecast delivery is to keep pace with rising demands, highest priority should be given to coupling probabilistic forecasting with forecasting the depth and velocity of inundation. This will require advances in forecasting science.