By Ian Joyner
Associate Director, Flood Risk, CBRE
Whether it is our famous obsession with the weather or the tendency of our ancestors to build on floodplains, the UK leads the way in making information available to the public about flood risk.
Property owners are just a few mouse clicks away from maps illustrating flood risk from numerous sources and can obtain real-time readings from local river gauges. In addition, the Government’s encouragement of ‘Open Data’ has been enthusiastically embraced by the Environment Agency and associated stakeholders. Companies are lining up to publish this information in easily-digestible formats.
Anything encouraging property owners to research their risk should most definitely be applauded. However, recent newspaper articles have highlighted an issue with such data. In effect, incorrect conclusions can be drawn which mislead the general public about such a highly technical issue.
The articles in question, summarised work by an environmental consultancy which used The Environment Agency’s ‘National Flood Risk Assessment’ (NAFRA) - a high level assessment utilising flood modelling to assess the residual risks and benefits of flood defences - to analyse properties at risk of flooding in each London borough. The articles concluded “people who live in Hammersmith and Fulham are at the greatest risk of being flooded” and “Hammersmith and Fulham was found to be the worst borough for potential flooding”. The wording of these conclusions fundamentally skews the underlying flood data.
It is true that Hammersmith and Fulham has a large number of homes and businesses located within an area of flood risk, but the Environment Agency notes that the risk is ‘low’ with an annual chance of flooding between 1 in 100 and 1 in 1,000. The majority of properties in the borough are protected by the Thames tidal defences, arguably the highest standard of flood defence anywhere in the UK, and face only a residual risk should these defences fail or be 'overtopped' during a storm.
Unprotected communities flooded in recent winters would gladly accept the residual risk of flooding facing Central London if similar defences were provided to protect their homes and businesses. Arguably, London boroughs facing actual risk of flooding were ignored in the coverage. The average residents of Enfield, Merton, Bromley and other boroughs would be unaware, despite local rivers exposing some properties to an annual chance of flooding greater than 1 in 30, without any flood defences in place.
For the average homeowner, sensationalist and inaccurate flood coverage may result in delays during a house sale or potential price adjustments. For commercial property owners, the stigma associated with potential flooding can have material impacts on the ability to attract tenants, the value of the property and development potential. In summary, a strong case remains for an expert review of flood risk, despite the rising tide of public data relating to this complex environmental phenomenon.