Understanding the national performance of flood forecasting models to guide incident management and investment

Centre for Ecology & Hydrology, Wallingford, Oxfordshire, OX10 8BB, UK

^a Corresponding author: stewells@ceh.ac.uk
^b Corresponding author: rm@ceh.ac.uk

Abstract

The preparation of routine flood guidance statements and formulation of incident management strategies requires national operating agencies to have a firm understanding of the performance of flood forecasting models. Studies of flood forecasting model performance are commonly evaluated on a groupedcatchment or local basis and can lack the analytical consistency required for integration into coherent national assessments. Here, the first nationally consistent analysis of flood forecasting model performance across England and Wales is presented. Application of the assessment framework, accounting for regional and model-type differences, yields a national overview of relative forecasting capability for models in current operational use. To achieve extensive site coverage, information from many existing local performance studies are pooled into a single structure for analysis under a national framework. The performance information spanning a variety of local models is also compared against the area-wide national G2G (Grid-to-Grid) distributed model. An integrated national assessment gives an evidence base of model performance useful for guiding strategic planning and investment in flood forecasting models. A concise single-page Performance Summary has been created for each site model that contains performance statistics, forecast hydrographs and catchment properties to aid operational use. A prototype web portal has been developed to make information on forecasting model performance more accessible and understandable for end-users.