Research that was presented at the Royal Geographical Society (with IBG) conference, which took place in Edinburgh on Wednesday (4 July), warned of the on-going flood risks to millions of city dwellers in the UK, as existing urban drainage systems struggle to cope with intense episodes of rainfall as has been seen in recent days.
As a number of events in recent years, and indeed the last week, have shown, the run-off resulting from such rainfall can quickly overwhelm systems, causing surface water to build up in low-lying areas, including in neighbourhoods which may or may not also be at risk of river or coastal flooding.
From modelling of at-risk areas in Glasgow, Belfast and Luton, the work also concludes there is a slightly increased risk of this ‘rain-related’ – also known as ‘pluvial’ – flooding, for people in vulnerable social groups. For example, lower income groups and renters are more at risk than because tend to live in low lying areas around town centres dominated by higher density terraced housing and flats.
Commenting on his work, Dr Alistair Geddes, University of Dundee, said: “Existing flood risk assessments are based on the number of properties at risk as opposed to the number of people. This approach downplays the impact on people, and in particular potentially vulnerable groups such as the elderly.
“We estimate that around two million urban residents are exposed to this kind of flood risk and that this applies more so to several vulnerable social groups. The number at risk is expected to increase by more than half, to 3.2million people, by 2050, largely the result of regional population growth, although changes in precipitation caused by climate change will also be important.”
The work concluded that population change has the potential to put three times more additional people at risk than climate change.
The research stems from a study on pluvial flooding in urban areas funded by Joseph Rowntree Foundation. Pluvial flood-risk is thought to represent around one-third of all UK flood risk. The study estimates that almost two million people in urban areas (settlements with a population over 10,000) face an annual 0.5 per cent probability (‘1-in-200 year’) of pluvial flooding. This represents around five per cent of the urban population, and around one-third of flood risk from all sources.
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