Flood, building on flood plains and the profile of those at risk

It is estimated that there are currently 1 in 6 properties or 4.7 million properties in Great Britain at risk from flooding, with 2.7 million properties at risk from flooding from rivers and sea alone.  Between 2001 and 2011, around 200,000 new homes were built on land that has a significant chance of flooding, either from a river or the sea. During the 1990s, this figure was even higher as there was less focus on flood and no obligation on planners to carry an analysis of flood risk at the time.

After the devastating effects of last winter’s storms and the subsequent costs to the insurance industry, building residential properties on flood plains continues although admittedly not in the same volumes.

Recent figures obtained by the i newspaper under the Freedom of Information Act show permission has been given to build more than 1,200 new homes on flood plains despite official objections from the Environment Agency about the risk of flooding on such sites. With all the publicity and available data relating to flood risk, it does seem slightly unbelievable that construction even at these levels is allowed to proceed, or at least without an obligation on builders to ensure that properties are built to be flood resilient.

New housing built in areas thought to be protected by flood defences may also be more at risk than first thought. Flood defences are built to withstand a certain magnitude of event, e.g. a flood with an estimated return period of 1 in 200 years, yet the underlying techniques modelled from relatively small data samples are based on extreme value theory which is sensitive to the underlying assumptions. I know there are still some people in senior roles in the world that are sceptical about climate change, however it does undermine the accuracy of these models and mean that defences may be more vulnerable than when first built or constructed. A good recent example being in Carlisle which flooded in 2005 (1925 homes and businesses) with flood defences that were breached. The defences were improved at a cost of £38 million yet these failed again in 2015 following a more extreme event than had been considered in the planning.

Profiling those areas hardest hit by flooding
We used our geodemographic risk profiling tool Resonate© to analyse the demographic profile of those affected by the Winter floods in 2015 in Carlisle and areas of Cumbria.   Our analysis revealed that there was an over-representation of properties flooded from working class and disadvantaged rural areas across the distribution of those hit.

Further analysis of these areas revealed a large number of properties flooded were from the Resonate lifestyle group ‘Rural & Village Survivors’ and those worst affected were predominantly from ‘Blue Collar Heartlands’; which are characterised by blue-collar workers in pre-war terraced properties where the proportion of terraced properties is almost thirteen times the UK average percentage. There is a high proportion of this type of neighbourhood in Carlisle.

Looking at all the areas across the UK that have a high risk of flooding does reveal that there is an over-representation of older, disadvantaged and more vulnerable neighbourhoods. In the future, we will no doubt continue to see more occurrences similar to that of Carlisle with poorer and more deprived neighbourhoods being disproportionately hit.

As long as there is still a demand for new houses, building on flood plains will continue. There is an increased demand for new housing particularly in the South East in areas where flood defences do exist, though climate change may limit the level of protection envisaged when some of these defences were built. A geodemographic analysis of the make up of the high-risk flood areas is quite startling – higher volumes of older, more disadvantaged and more vulnerable members of society dominate.

This highlights the important role that insurance plays and how the availability of affordable flood insurance for everyone is essential.  The introduction of Flood Re goes some way towards offering flood-prone properties a degree of cover but does not yet guarantee affordable insurance for everyone. The Government will need to put more investment in maintaining and improving flood defences and will need to look at helping make properties in the highest risk areas more resilient to damage from flooding.