Comparing the scale of modelled and recorded current flood risk: Results from England

Abstract

As the Sendai framework recognises, understanding the nature and severity of risk is an important prerequisite to sensible risk reducing measures. The UK has been in the forefront of assessing the scale of flood risk at a national level to inform investment and policy directions but the scale of this risk, as modelled, has reduced since 2014. This paper compares the most recent modelled version of national flood risk, in the form of the Environment Agency's State of the Nation report, with loss figures quantified in terms of insurance claims data for the period 1998 to 2018. Depending on assumptions, the results show that the modelled results are between 2.06 and over 9.0 times the comparable flood losses measured in terms of the compensation paid to flood victims by insurance companies. The reasons for these differences remain unclear but several possibilities are reviewed. Many of these reasons appear implausible, but the divergence between the two sets of results should encourage the users of this data to consider carefully their assessments of the true scale of flood risk that the country faces, and perhaps promote similar comparisons in other countries.

Effect of flood risk management methods on urban flooding: Article review

“…State of the report, with loss figures as measured in terms of insurance claims data [46]. There is also a secondary qualitative approach that explains that research is based on knowledge about the role of protected forests which is expected to be a reference for determining targeted actions about protected forest management in the context of handling hydrometeorological disasters [10].…”

“…38 Rowsell 2020 This study compares the latest models the version of national flood risk, in State Environment Agency form of the report, with loss figures measured in terms of insurance, claims data for 1998 to 2018 [46]. 39 Netzel 2020 A questionnaire-based telephone survey was conducted to understand better the processes underlying public risk perceptions of pluvial flooding [47].…”

An Integrated Framework for Risk‐Based Analysis of Economic Impacts of Drought and Water Scarcity in England and Wales

“…Floods cause more frequent and severe economic losses in England than droughts, so it is possible to generate empirical estimates of economic losses from flooding based on insurance data, from which direct EAL is estimated to be approximately £100 million (Penning‐Rowsell, 2020). This first probabilistic estimate of economic losses from droughts has yielded an EAL of £11.7 million, which, as we would expect, is significantly less than the expected loss from flooding, but still significant.…”

Supplementary material to "A climate-conditioned catastrophe risk model for UK flooding"

“…The methods underpinning the NaFRA analysis have changed significantly over time, but these modifications are rarely disclosed publicly. Indeed, it has taken significant detective work by Penning-Rowsell (2014) and Penning-Rowsell (2021) to uncover even limited aspects of the approach and differences from RASP. A major change occurred in 2008 when the simple non-hydraulic method for floodplain depth estimation was upgraded to use HR Wallingford's Rapid Flood Spreading Model (RFSM).…”