Flood debate: Should we build on floodplains?
Weeks of storms has reignited the debate over whether to build on floodplains, with a growing number of voices claiming they should be a ‘no go zone’ for much-needed new housing
Thousands of homes remain submerged following the wettest January in 250 years, with 16 severe flood warnings still in place in southern England.
Yet plans have emerged for hundreds of houses in flood-hit areas such as Wraysbury in Berkshire and Chertsey in Surrey and there are claims thousands more of similar homes are slipping under the radar.
According to the Sunday Times, local councils are often failing to inform the Environment Agency when they have overruled the government body’s objections and allowed developments to go-ahead.
Speaking to the paper, John Krebs, the chairman of the climate change committee which raised the alarm about the growing number of homes in flood-risk areas, said: ‘We are still slapping up homes and business properties in flood plain areas.
‘We’ve adopted the build-and-defend approach in the past and we need an honest assessment. Is build and defend the right way, or do we say we will stop building homes in flood risk areas, we’ll just build elsewhere?’
Shaun Spiers, chief executive of the Campaign to Protect rural England, believes the coalition government must shoulder some of the blame. He said: ‘The government sees all development as good and is obsessed with cutting what is seen as red tape.
‘But as recent weeks have shown us, some regulation is sensible and necessary.’
He added: ‘They are encouraging building on floodplains because what they are saying is “We need new houses for economic growth and by the time things flood we’ll have more money to cope with it.’
Between 2001 and 2011, it is thought around 200,000 homes have been built on floodplains. More and more schemes include features which make them flood resilient, such as lifting living spaces off the ground floor.
This is not enough for flood consultant Mary Dhonau – dubbed ‘Mary Queen of Floods’ – who told the AJ: ‘Yes it is possible to build cleverly on the flood plain. But it’s just not happening.
‘Until clever’ building becomes the accepted norm, then it should be put a halt to.’
Mark Wilson, chief executive of insurance giant Aviva, agreed.
He told the Sunday Telegraph: ‘As a nation we need to build more homes, but the cost of development must include the cost of defences. Let’s be crystal clear: no defences, no development.’
However speaking on BBC television yesterday (16 February) defence secretary Philip Hammond said: ‘The guidance on building on flood plains is very clear. But look, the whole of the Thames Valley is a flood plain.
‘There has to be a proper balance. We need to avoid the highest flood risk areas. When we do build in lower flood risk areas we need to make sure that properties are built in a way that minimises the risk of flooding, both at the level of the individual property and at the way development is designed.
‘It’s very easy to say today, because we are in the middle of this crisis, flood resilience is the only issue. It’s a very important issue but it is not the only issue. We have to balance economic growth, maintaining people’s standards of living, flood resilience in the long term – all of these things need to be balanced together.’
Architects also have not been unilaterally opposed to building on floodplains. John McRae of ORMS said: ‘In our continued struggle to resolve the housing crisis the government has seen fit to encourage, or at the very least has not discouraged, development in flood plains. This in itself is not an issue however it is the lack of flood defences that is a fundamental flaw with this type of development.
‘If defences are not provided why is the housing not designed to be on stilts or the land sculpted to prevent water ingress?’
Kiran Curtis of KCA architects said that a lack of available land was forcing councils to allow development on sites prone to flooding.
‘We are working on a project in Tunbridge and the site we are looking at is at risk of flooding. A strategic decision has been made that these sites will be considered as long as design solutions can be found,’ said Curtis.
‘The first thing architects should consider,’ said Curtis, ‘is the nature of flood risk: ‘How high does the water get, how quickly is it moving and is it ground, fluvial or surface water?’
‘The second course of action is to try to prevent that water getting to the houses in the first place.’
Raising or re-profiling the site to push the water away are options as is re-landscaping to create zones where excess water can be stored. In addition Curtis said sub stations should be protected and more extensive works can be carried out upstream to reduce the amount of water hitting the homes.
If floodwater is still likely to enter homes raising the living areas off the ground floors should be considered: ‘It is not a desirable way to go but it is viable and there are areas where people living in that way.’
‘For example on one of our schemes you come in at ground level to an area that is almost sacrificial with surfaces that can be cleaned quickly; up a half landing on to the kitchen and living areas which are a metre above the flood plain.’
‘And in our scheme in Gravesend several hundred houses are at risk from both tidal and storm surges so we have raised the entire ground floors.’
But Curtis said that he had doubts whether schemes that involve floating houses would be effective in the current extreme conditions. He said: ‘My feeling is that there are some very interesting examples of floating houses but they are often in Holland in areas called polders that are areas that are allowed to gently flood in a managed way.’
Here it is a bit different as there is rapid ground water flooding and fluvial flooding.’
Other design elements architects could think about are running electrics from the ceiling down the walls and specifying non porous materials for surfaces.