Why we need to talk about floodplains
Why are we shocked when properties built on floodplains are inundated with water? Let us not forget what a floodplain really is. It is not just a piece of land near a river. It is part of the riverine system. And as the name would suggest, it is supposed to flood.
In July 2021, heavy rain fell across the UK and western Europe resulting in more than the average monthly rainfall total to be recorded in a 24-hour period across parts of England. London suffered considerably. Residents displaced, bus passengers rescued by raft, train stations submerged, utter travel chaos became familiar scenes of the city inundated by floods.
Heavy rains and floods are becoming more common. This summer showed that London, like many urban areas, is not ready for climate change, with large parts of the capital and indeed the country built on floodplains.
While the madness of building on floodplains is widely acknowledged, it still seems to happen.
With England in the throes of a housing shortage, central Government has promised to build 300,000 more homes a year by the mid-2020s. Yet, targets given to local authorities ignore local flood risk and instead are based on factors, including expected demand and recent construction rates. In England, 10% of all new homes since 2013 have been built on land at the highest risk of flooding and almost double the number of properties built at highest flood risk, in Flood Zone 3 – an increase from 2.4 million to 4.6 million – is anticipated over the next 50 years.
The problem is getting worse as local authorities are under enormous pressure to build homes, regardless of how suitable their land is.
While the Government generally advises against building in areas at high risk of flooding, it is simply advice and not imperative. If deemed necessary, developers can conduct a flood risk assessment and consider mitigation measures; plans which are reviewed by the Environment Agency but whose suggestions do not have to be followed.
In fact, the numbers of homes being built despite the Environment Agency’s opposition are increasing as part of a broader trend, with developers striving to push through more projects on land at high risk of flooding to satisfy housing demand.
The power to stop a development rests with the local planning authority, who may often feel under pressure to acquiesce to development requests. Once applications are submitted, if the council objects, developers simply lodge an appeal which is often won.
Advised abstinence for building on floodplains alongside the mandate to increase housing stock presents a stark contrast. The planning system has gone awry and morphed into a housebuilding system, resulting in constructing properties that will flood, either through poor design or flood risk.
But building on floodplains shouldn’t simply be prohibited. Indeed, for some areas it cannot be, such as South Holland, where 34% of the district’s land is at high risk of flooding and have little choice but to build on floodplains to meet local housing demand.
Similarly, more than one million Londoners live on a floodplain – ceasing to build there does not sound plausible. However, it is crucial that effective resilience measures are incorporated into any scheme.
We must continue what has already been done for a while: building and maintaining strong defences to reduce the risk of communities being flooded. But, in the face of climate change, a second, parallel track is necessary: making communities more resilient to flooding so that when it does happen – and it will – it poses much less risk, causes less damage, and can be recovered from quickly.
In this vein, Localis is working to create a holistic review into the future for resilient building of homes in floodplains set against the policy context of the Government’s agenda for housing and climate change.
Local authorities are vital in this more holistic approach to flood risk management. Yet they are drowning under the pressure to balance housing targets with a scarcity of suitable land and growing climate threat.
Continuing to build new homes in floodplain areas without resilience measures is a planned catastrophe. Clearly defined flood resilience objectives from the national Government are needed to protect homes and businesses in line with climate change projections. The Government needs to ensure the new flood and coastal erosion risk management plan is reflected in local plans with councils supported to implement the new strategy locally. It needs to be guaranteed that those profiting from building new homes on floodplains contribute to flood mitigation measures and that these homes can be insured.
Currently, central Government is simply not doing enough to protect the UK’s current housing stock from flooding or intervening to prevent new homes being built on floodplains. Only a whole-systems collaborative approach in which councils, armed with the capacity to plan for local climate change, solely determine location will do.
Grace Newcombe is lead clean growth researcher at Localis