Building a model to estimate risk to life for European flood events – final report

The research carried out for Activity 1 of Task 10 focuses on developing a methodology to estimate loss of life from flood events. In order to reduce the risk to life it is necessary to understand the causes of loss of life in floods in order to pinpoint where, when and how loss of life is more likely to occur and what kind of intervention and flood risk management measures may be effective in eliminating or reducing serious injuries and fatalities. The objectives of this research were therefore to (a) further develop a model, or models, to provide insight into, and estimates of, the potential loss of life in floods, based on work already undertaken in the UK and new data collected on flood events in Continental Europe; (b) to map, through the use of GIS and building partly on existing work, the outputs of the risk to life model(s) providing estimates of the potential loss of life in floods. The research took as a starting point the Risk to People model developed in the UK (HR Wallingford, 2003; 2005) and assessed the applicability of this model for flood events in Continental Europe, which tend to be more severe and life threatening. Data on flood events were gathered from 25 locations across six European countries as well as data from an additional case study in the UK. A number of problems were identified with the current model when applied to the flood data collected from Continental Europe. In particular the model was not designed for the major rivers and mountainous catchments compared with the UK and thus resulted in dramatic over-predictions of injuries and fatalities. Moreover, the model was found to contain several structural weaknesses. Research conducted into the factors surrounding European flood fatalities also highlighted the importance of institutional arrangements and mitigating factors such as evacuation and rescue operations. Finally, the UK model was seen to be hugely sensitive to people vulnerability, which in much of the wider European flooding is arguably of less importance in than it is in the UK. Thus a new semi-qualitative ‘threshold’ model which combines hazard and exposure thresholds and mitigating factors has been developed to assess risk to life from flooding in a wider European context. The model has been designed to be flexible enough to be used and applied at a range of scales, from a broad assessment at a regional or national scale, to a more detailed local scale. This flexibility is essential as not all European countries have detailed flood data that is readily available. It is envisaged that the model should be used as a tool to allow flood managers to make general and comparative assessments of risk to life and to consider the targeting of resources before, during and after flooding. The new model also permits simple mapping of risk to life which again can be applied at various scales