It feels as if the UK floods were many months ago. But Storm Jorge was at the end of February and came following two back-to-back storms, Ciara and Dennis. From Derbyshire to South Wales to Ayrshire, communities are still cleaning up the damage, families waiting to return home. The COVID-19 outbreak, the only news for most people, is an additional burden.
Floods, say those paid to think about them, are a “wicked problem”, impacting life in complex, sometimes paradoxical, ways. They connect to many other issues, from farming to social history. Rain gives life; a centimetre of water can make a house unliveable.
For years, responses to floods – from government agencies and insurers – were essentially crisis management, dealing with each disaster as it occurred. But a new generation of scientists, architects and builders are proposing proactive solutions to reduce flooding where possible, and make floods less damaging where they are inevitable. The consequences of floods typically exacerbate the climate crisis; but the latest innovations seek to mitigate it, cutting carbon emissions and improving biodiversity.
Realigning the environment
Natural flood management (NFM) is the term used by environmental scientists and hydrologists for the new approach. Far from letting nature have its way, it’s all about smart intervention.
“We’ve been managing nature for centuries,” explains professor Iris Moeller, a geographer specialising in coastal geomorphology at Trinity College, Dublin.
“But in the past we’ve tried to understand the rules of nature to defend against them. We now use NFM to understand those rules so we can better adapt. It’s a change in attitude. We don’t just build a high wall. We intervene in processes so that we don’t need such a high wall in the first place.”
The Environment Agency lists 14 “working with nature” processes, which include restoring bends in rivers, blocking leaky barriers, changing the way land is managed and creating saltmarshes on the coast to absorb wave energy.
“A lot has to do with upland river management and land use,” says Moeller. “The thing we’ve often bodged, historically, is agricultural and land management practices. Deforestation is an example. We have destroyed natural sponges.”
Slowing down rainwater is often the goal. When water builds up and has nowhere to go, it causes problems. A fix upriver can lead to a bigger problem downriver. But at the mouth of a river you might want to move the water quickly, which can be problematic if there is also tidal seawater.
“London faces a double whammy,” says Moeller. “One day in the future—and we don’t know when—a low-pressure storm system will bring heavy rain and also raise the sea level. Combine that with a spring tide. Closing the Thames Barrier would become necessary but would lead to a rising of the river water— a Catch-22 situation and a flood in the city.”
Computer modelling is used to predict where and how floods might develop. Now new technologies, particularly in the surveillance sector, allows scientists to crunch more accurate numbers.
“In the recent floods we saw some great use of drones and camera footage to help capture NFM measures in action,” says Lydia Burgess-Gamble, a principal scientist specialising in flood risk management at the Environment Agency.
“This can be used to see if they are working and also as a tool to help demonstrate their effect on communities.”
New ultra-high-resolution satellite imaging could revolutionise the study of floods. Miniature satellites known as “doves” manufactured by San Francisco-based Planet Labs Inc—whose stated goal is to image the whole planet daily—mean flood-managers can access the latest laser-based LiDAR (Light Detection and Ranging) technology.
According to Moeller, “It’s not going to be long before we can use technologies from space to measure the thickness of sand and the erosion rate of a dune with unprecedented accuracy and frequency.”
Satellite data, she says, “could function to provide an early warning system. Using drones and satellites with infrared technology, we can distinguish different vegetation types. We can even measure the vigour with which the grass is growing and the degree to which it acts as a natural sponge.”
A holistic approach to design
Sometimes we build in the wrong places. Just as often we build the wrong kinds of structure. That’s why one in six houses in England is currently at risk of flooding, a number that could double by 2030.
According to Edward Barsley, author of Retrofitting for Flood Resilience and founder of the award-winning The Environmental Design Studio, architects and builders should approach design with the same degree of sensitivity as natural flood engineers manage landscape.
“People look for a silver bullet, but we have to tailor specific measures to communities. A strategy for Calder Valley would be different from one for the Somerset levels.
“A barrier can work in some places. Storage might be best in others. Hard engineering is not always the solution. The worst thing we can do is copy and paste.”
With any new build it’s obvious we shouldn’t be displacing or holding back water. A floodplain is a water feature if you are looking down on it from, say, a stilted house.
But the same principle holds for houses that are already standing, says Barsley.
“When a property is flooded, insurers, to date, have helped people get ‘back to normal’, but a flood, once passed, is a time to think about retrofitting a building.”
Retrofitting, he explains, might include raising sockets, making fixtures movable, raising floor levels or installing a stainless steel kitchen to minimise flood damage.
“Flood resilient design should not just be seen as a necessity, but as an opportunity through which to deliver wider benefits such as improved biodiversity and to enhance the quality of placemaking in communities throughout the world.
Saving for an un-rainy day
Another compelling reason for flood management is droughts. On June 10, 2019, the UK had more than a month’s rain in a single day. There was localised flooding the following week in the north of England and Midlands. Sinkholes appeared on the M25. Railway lines were closed. Yet groundwater levels across the country were lower than normal. Lawns turned yellow. The simple fact is, very dry land can’t absorb heavy rain and so aquifers run dry.
“NFM has been typically focused in the UK on flood management,” says Burgess-Gamble. “But there is a sudden upsurge in using nature-based solutions to solve a range of environmental issues including, droughts and water quality. I think we will start to see a move to using NFM to deliver a wider range of ecosystem services.”
She points to the work of NGO The Flow Partnership in India. In the Ganges Basin – one of the largest water catchment areas on earth—land use is being mapped and underground storage schemes studied as groundwater resources increasingly struggle to meet massive demand, especially from the agricultural sector—a problem likely to be exacerbated by climate change.
A community solution
House builders are slow to change their practices. The elemental nature of floods means people always want to think about anything else, especially when the sun’s out.
But scientists, developers and communities are starting to work together, as at Building With Nature, a collaboration between Gloucestershire Wildlife Trust and the University of the West of England, which aims to establish a new benchmark so that houses can be assessed and accredited for their environmental design.
Barsley believes the new Property Flood Resilience Code of Practice, formulated by the not-for-profit Construction Industry Research and Information Association and Building Research Establishment—released on February 10, 2020—could be a game-changer.
“Houses could be rated flood resilient, rather like an EPC rating or an MoT. A good flood rating could add value to a home when it came to reselling.”
The impact of floods on climate change is also a major factor. Forests and fields are destroyed. Afterwards, houses are stripped of their contents and dehumidifiers run for months.
If the central purpose of NFM and new housing regulations is to protect humans and homes, a close second is nature itself.
Returning rivers and coasts to a more natural state has benefits for habitat diversity, biodiversity and the entire water-based ecosystem. Restored rivers, combined with revegetation, can provide a sink for carbon and other pollutants.
“We need to think creatively about where we build and how we build,” says professor Iris Moeller. “Natural Flood Management schemes tend to have a positive effect on biodiversity and a clean environment.
“Whether NFM wins the battle against money is the question. We need more than a cost-benefit analysis to decide whether something is good. We need to stop thinking about barriers and think instead about sustainable, long-lasting, win-win solutions.”