Flooding is a killer. The stark reality of this was never clearer than 10 years ago in the UK, when 13 people died and about 55,000 homes flooded in a series of devastating storms.
An unprecedented amount of rain fell in May and June 2007, affecting nearly every part of the country, causing untold damage to those areas they hit.
A decade on, and flooding still kills, says Environment Agency executive director of flood and coastal risk management John Curtin. But after more than £6bn of government funding, big improvements have been made in the way high water levels are dealt with, before and as flood events occur.
Curtin explains that after 2007, the review carried out by Sir Michael Pitt led to the Floods & Water Management Act, which improved the oversight of flooding and a kicked off a new era of technological advances in flood risk assessment.
But the big push to improve the UK’s flood defences and flood response has not been an easy one. Today, a staggering 5M households, equating to around one in six, remain at risk of flooding. New data from the Met Office says that there is now a 1 in 3 chance of a monthly rainfall record being broken each year.
“We’ve got a climate that seems to be changing quite rapidly,” says Curtin. “You get general trends, but then you go to the 2007 floods and they really showed that we’re facing a huge challenge.
Severe storms, like the one which we had in Coverack in Cornwall this year, have very little warning but they can create huge amounts of rain
John Curtin, Environment Agency
“It’s an ongoing battle. We’ve made a lot of progress, but we have to make sure that our thinking changes faster than the climate.”
Curtin says there are two sides to dealing with flood risk and both must be understood at the same time to get the best outcome. The first is building defences which protect land from incoming water surges, the second is preparing for and dealing with floods when they happen.
To reflect this, government cash has been split into two parts to cover flood defence construction and flood preparation. The Agency is in now in the middle of a six year period in which it is spending £2.5bn on defences alone. This it says will reduce risk of flooding from rivers, the sea, groundwater and surface water for at least 300,000 homes by 2020/2021.
“The government is spending more on flood risk management than it ever has before,” says Curtin. “Not just the capital spending but protecting and maintaining the assets we’ve got.”
Maintaining flood defence funding
With around 7,000km of flood defences on rivers and 22,000 flood defence structures, some as big as the Thames Barrier, he says having enough funding to maintain the current stock is just as important as funding the construction of new ones.
But building new defences is not just a case of building huge, monolithic concrete structures to keep the water out. He says involving the community and being sympathetic to its needs is the key to building a successful scheme.
New high and low tech innovations have gone into building new defences. In certain areas, he says, building intrusive barriers would destroy the relationship some areas have built up with the water around them. As a result, new approaches have been adopted at Upton-Upon-Severn, Medmerry and Cockermouth (see boxes).
Generations of engineers have helped make the country more resilient, but you can’t get complacent
John Curtin, Environment Agency
One of the major problems in dealing with the aftermath lies in being able to predict the duration and severity of a flooding event, says Curtin. At one end of the spectrum a big storm coming over the Atlantic Ocean might coincide with high tide creating a tidal surge which can be predicted a few days ahead. But at the other extreme, he says summer thunder storms or “convective storms”, can form over land in as little as an hour, dumping huge amounts of water without much warning.
“Severe storms, like the one which we had in Coverack in Cornwall this year, have very little warning but they can create huge amounts of rain, maybe 100mm in a couple of hours.”
Work to improve the ability to predict certain storms and give as much warning as possible is another of the success stories of the investment programme over the last 10 years.
“Detecting it, forecasting it, predicting what it’s going to do and then people responding,” he says. “You’ve got to be careful you don’t have any weak links in that chain.
“We’ve spent quite a lot of time and effort since 2007, strengthening that chain.”
In response to the Pitt review, the Flood Forecasting Centre set up by the Environment Agency and the Met Office went live in 2009. The round the clock centre “blends the expertise of the meteorologists in the met office with the expertise of the hydrologists in the Environment Agency”, according to Curtin. It also provides the police, fire brigade and other bodies with daily, accurate weather reports.
At risk residents
At the other end of the spectrum, the Agency has been working hard to warn residents in areas vulnerable to flooding from unpredictable summer storms that they and their properties are at risk.
These include those living in steep, narrow valleys where rain could rush down the slopes, or whose properties are in areas of hard, impermeable slate and which are prone to flash flooding.
“It’s a range of topography, geography and geology,” says Curtin. “It means that the time between when the rain finishes to when the river peaks is very small. If it’s an hour or less, there’s very little you can do other than know you’re in that type of catchment and know the risks.
“Communities need to play a part. In these rapid response areas, we’ve talked to the communities and the local authorities, to make sure they know they live in one of these areas, and for example, make sure they don’t put a campsite there.”
When a storm looks threatening in such areas, people signed up to the Environment Agency’s national alert service will receive texts, phone calls and twitter alerts to warn them of impending danger.
To further enhance its flood prediction capability, the Environment Agency has invested in acoustic remote controlled (ARC) boats to collect data on river flows and depths and is using light detection and ranging technology to monitor the performance of its assets.
“Generations of engineers have helped make the country more resilient, but you can’t get complacent,” he says. “We all have a part to play and we all have a role in flood risk management.”
The area of Upton-Upon-Severn has a close relationship with its river. Pubs, bars and restaurants all line the river front, attracting locals and tourists. But in 2007 after heavy rainfall, the river burst its banks and flooded large swathes of land around it.
In response, in 2012, the Environment Agency completed a £4.6M scheme which, among other things, included a 300m long flood wall topped with a glass wall along the river bank to keep flood waters contained.
“There was a big dilemma there for us, creating a massive wall that would close them off from the river and destroy their relationship with the river,” says Curtin. “So we came up with something else.
“For the first time in the country, we put in glass panels along the top. It’s just as stable and resilient as a wall, but it keeps the view of the river.
“In a recent flood, it became a bit of a tourist attraction in itself and there were some people standing behind the wall with their pint, with water half way up the glass on the other side.”
The wall has been hailed as a massive success allowing people to still see the river while remaining protected. The wall also incorporates gates, giving access to beer gardens on the banks when the river is low.
River penk flooding, 2007, photo from ea cd
The rivers Derwent and Cocker caused serious flooding in Cockermouth, Cumbria in 2009 and 2015.
But in 2013, the area underwent a transformation, with a new flood risk management scheme to protect approximately 260 homes and 55 businesses. On the back of the success of the Upton-Upon-Severn scheme, glass topped walls were installed to protect the river banks. But here the Agency also took it one step further.
New stone-clad concrete defence walls containing 120m of self-closing barriers which raise the height of the wall during a flood were installed. Should a flood occur, inlets in the wall allow the water to flow in raising the water level in a chamber within the flood wall – pushing the 10 barriers up.
“CCTV and telemetry allow the Environment Agency to monitor each barrier individually,” says Curtin. “They’re fully automatic – and it’s the first time they have been used in the UK. It’s the first time they’ve been used over linear length (one next to the other) in the world.”
Medmerry Coastal realignment
The area of Medmerry on the coast of Sussex was prone to flooding. In 2008, the sea breached the shingle sea defence causing around £5M of damage to the nearby towns of Pagham and Selsey.
The increasingly ineffective barrier was becoming increasingly expensive to maintain, so the Environment Agency decided to take a new tack.
After negotiating with the local land owners, the agency decided to carry out its largest managed realignment schemes. As part of this, it allowed the sea to breach the shingle defence, flooding an area of low grade farm land along the coast. By doing this, it created a salt marsh buffer between the sea and the nearby towns, allowing a smaller, more maintainable defence to be built inland. In total, around 300 homes have been protected by the new measure.
The area is now a bird sanctuary as the salt marches have created a 73ha nature reserve.