Flood Forecasting Model Selection

Flood forecasting models provide the capability to issue reliable warnings to the population at risk of flooding. The categories of models developed over the years range from simple empirical models to integrated catchment models combining rainfall runoff, flow routing and hydrodynamic components. This paper describes a novel structured method for selecting the most appropriate category of modelling solution to use in a given situation in the form of guidelines commissioned by the Environment Agency for England and Wales. One outcome of this approach is to provide greater consistency and auditability in the design of flood forecasting systems, and to ensure that practitioners are aware of the assumptions, limitations and likely accuracy of each approach. The resulting guideline document considers economic, operational and other factors, as well as technical factors such as catchment characteristics, and makes extensive use of checklists, flowcharts, risk assessment matrices and other techniques for guiding users through the decision making process. The guidelines are currently being used operationally and an overview is presented on experience gained in the first year since publication. A number of areas for future research and development are also highlighted which were identified during preparation of the guidelines