"One English Town’s Innovative Response To Sea Level Rise"
Vast stretches of the Somerset Levels, an expanse of coastal plains and wetlands in southwest England, have spent much of the winter underwater. At the peak of the crisis, some 11,500 hectares (28,420 acres) was submerged as violent storms brought “biblical” deluges week after week, for months on end. Along Britain’s scenic coastline, 80 mph gales and tidal surges have left cliffs crumbling into the rough sea, beaches and sand dunes eroded, sea defenses breached, and shorelines and harbors damaged beyond recognition.
The cliffs at Birling Gap on the East Sussex coast have suffered seven years of erosion in just two months, as over nine feet of the soft chalky cliffs fell into the sea. At Formby, on the Sefton coast, the sand dunes saw two years worth of erosion in just one epically stormy December afternoon. At South Milton Sands in Devon, sand dunes have been completely destabilized and fences and boardwalks washed away. And the list of destruction goes on and on.
All along the coast of the U.K. and in other coastal communities around the world, the threat of sea level rise and more violent storms is forcing towns and governments to make difficult choices — build higher, build stronger, or retreat. In the U.S., both strategies are being explored. Famous for its levy system, New Orleans is now also incorporating open spaces designed to flood into city planning, following designs pioneered by the Dutch. For its part, much of the New Jersey coast, devastated by Superstorm Sandy, is choosing to rely almost entirely on bigger artificial sand dunes to hold the ocean back as towns attempt to rebuild right where they were before the hurricane hit.
The U.K.’s Environment Agency is experimenting with a kind of coordinated retreat for the hardest to defend coastal areas, a tactic referred to as managed coastal realignment. It’s a controversial approach for a relatively small island nation. But the recent wild winter storms are starting to change attitudes — strategic surrender suddenly seems like it may be the smart, sustainable solution.
Getting Smart, Not Giving Up
Hostile and fearful, that’s how Adrian Thomas describes the mood in the room when West Sussex residents were told that the Medmerry sea wall in the south of England would no longer be defended.
“People thought we were giving up,” said Thomas who works as a project manager for the U.K.’s Royal Society for the Protection of Birds (RSPB). “People wanted to know why we couldn’t just build a bigger sea wall or make it out of concrete. After so many years of fighting this fight, no one wanted to hear that we just weren’t going to fight anymore.”
What the community was being presented with back in 2008 were plans for the largest ever managed realignment of the U.K. coast — effectively moving the coastline several kilometers inland. For decades, the Environment Agency, charged with managing flood defenses in the U.K., has maintained a one kilometer sea wall built out of shingle — a shingle bank — from the beach along the coast between the town of Selsey and Bracklesham on the Manhood Peninsula in southern England.
CREDIT: UK Environment Agency/Andrew Breiner
Since the 1990s, the probability of the shingle bank being breached in any given year, however, was one in one, necessitating that the Environment Agency haul a fleet of diggers out to the beach each winter and reconstruct what nature seemed so determined to destroy. The average price tag for this un-winnable war was around £200,000 ($332,000) annually. Were the bank not repaired, however, the likely inundation zone would include the only road to Selsey, 360 homes in Selsey, a water treatment plant serving 12,000 people and multiple seasonal vacation home developments with hundreds of rental cottages. The last time the wall was seriously compromised during winter storms was in 2008. The resultant flooding cost over £5 million ($8.3 million) in damages.
The controversial plan? Cut a 100 meter channel into the shingle bank and let the ocean reclaim 500 hectares of land, transforming three farms and the RSPB nature reserve into a saltwater marsh. Then behind the newly created inter-tidal zone, about two kilometers inland, build a new seven kilometer curved clay embankment — completely “realign” the coast. The price? £28 million ($46.5 million). The coastal realignment not only moves the sea wall further inland, it also creates a powerful buffer zone of marsh that can absorb storm energy. Interestingly, there is archeological evidence that the area was originally dominated by saltwater marsh hundreds of years ago.
“If you do the math, you can’t help but wonder how a scheme that cost £28 million ($46.5 million) can be justified if it only costs £0.2 million ($332,000) to maintain the sea wall each year,” said Thomas of RSPB which owned the 50 hectares of land adjacent to the old sea wall. “But of course, it’s £0.2 million ($332,000) based on current sea levels. If you factor in sea level rise due to climate change — about an extra meter in the next 100 years — and the fact that the south of England is still tipping into the sea after the last ice age, that’s just not going to be the price in the future. Never mind the financial side, it may simply not be technically feasible.”
The past winter was incredibly revealing. Andy Gilham, the Environment Agency’s Regional Flood Risk Manager, believes that because of the intensity and repetition of the brutal storms that pummeled much of the U.K. with hurricane force winds and relentless rain for months, the agency just would not have physically been able to maintain the shingle bank this year.
Fortunately, the Medmerry Managed Realignment Project was completed in November after two years of construction work and just weeks before the first of the winter storms rolled in around Christmas. And the general sentiment among the project leaders and business owners and residents is that the very non-intuitive plan of punching a hole in a flood wall to reduce flooding, actually worked.
“The mood music has definitely changed,” said Thomas. “From hostile and fearful to delighted and surprised.”
Allan Chamberlain, the Estate Director at Medmerry Park Holiday Village, a development consisting of 308 vacation rental homes adjacent to the realignment scheme, will readily admit that he is shocked by how well the realigned coastline protected the area from this winter’s epic flooding.
“I think initially we had the impression we were giving up and just letting it flood,” said Chamberlain. “But when you look at it now, you can see that it is progress, not defeat. Not only were we not flooded by the sea, but the project also appears to have made the surface flooding from rain less severe. The rainwater drains into the new marsh beautifully.”
“It’s the first winter in years we haven’t had to deal with surface flooding,” he added. “We were all hoping the project just wouldn’t make it any worse, but it appears to actually be making it much better.”
Chamberlain is also thrilled about the new tourist attraction created by the expanded nature reserve. He has already noticed an increase in visitors to the park even though the season has barely begun and not all the trails around the reserve are finished. Before the realignment project there were just two short stretches of public foot paths around the small, 50 hectare RSPB reserve. Now there are 10 kilometers of foot paths and seven kilometers of new bike paths in an area completely dependent on tourism for the local economy. In addition to attracting more people, the project has also actually extended the tourism season in the area. Bunn Leisure in Selsey, the largest vacation home development in the area, once only allowed to be open for eight months because of the risk of flooding, can now extend its season for an additional two months. The vacation home park employs over 300 people.
Chamberlain is applying for a similar permit extension.
‘We Are Very Aware That We Live On An Island’
Not everyone shares Chamberlain’s enthusiasm. Ben Cooper, who owns an IT consulting company and is a member of the Selsey Town Council, still has his concerns. He would have liked to see the Environment Agency consider other alternatives such as constructing rock barriers out in the ocean in front of the coast to break wave energy.
“When you live on a small island like the U.K. it’s hard to see land go,” he said. “I think we gave up too easily and before the Environment Agency tries this somewhere else, I hope they wait and see how the project stands the test of time. Once you give land back to the sea, there’s no getting it back, so if this doesn’t work, we will have given up that land for nothing.”
One of the especially contentious issues at the beginning of the Medmerry project was the fact that in order to create the realignment project, three productive farms growing oilseed rape and winter wheat would have to be sacrificed to the sea.
“In the U.K. we are very aware that we live on an island,” said Thomas. “We know we’re not self-sufficient already, so the idea of letting go of perfectly good agricultural land struck many people as wasteful and short-sighted.”
Indeed, around the U.K. this winter, the fact that developed property is given priority for flood protection over agricultural land has led many people to question the sustainability of the Environment Agency’s approach.
The area won’t lose all of its food production value, however. The newly created estuary-like environment is expected to become an important fish nursery that will boost the local commercial fishing economy in Selsey. The salt marsh vegetation will also be farmed — not the waving wheat and barley people are accustomed to, but the land can be used for low intensity cattle grazing to produce salt marsh beef a premier meat product.
The people with the biggest reservations about the Medmerry project are actually not from the area at all.
“People in Somerset who have had to endure terrible flooding this winter are quite upset about the whole thing,” said Chamberlain. “They want to know why the Environment Agency is spending £28 million on a ‘bird park’ when they could desperately have used those funds to dredge rivers and mitigate flooding in their area.”
As it turns out, the only reason the Environment Agency was able to set aside the money for the Medmerry scheme was precisely because they were creating habitat for birds. As Andy Gilham explained, under the E.U. Habitats and Birds Directive, the U.K. is required to compensate for wildlife habitat being destroyed elsewhere along the coast by creating new habitat. In the south of England especially, areas designated as Special Areas of Conservation along the Solent strait between the Isle of Wight and the mainland are being lost through a process known as “coastal squeeze.” Coastal squeeze refers to the loss of coastal habitat as land on the seaward side of rigid coastal protection structures is eroded away. The Medmerry project created nearly 200 new hectares of wetlands with similar ecological functions as the areas being lost to the west.
While the Environment Agency has done smaller coastal realignment projects in the past, Medmerry is by far the largest and the only scheme that realigns open ocean coastline, as opposed to coastline along an inland estuary. Projects similar to Medmerry are already under development. In May 2012, the Environment Agency began construction work on a coastal realignment project on the Steart Peninsula in southwest England. The project will create a new 400 hectare and provide flood protection for Steart village.
“I do feel resonance with the kind of gut human instinct that says we can win against nature,” said Thomas. “Surely we have the technology and fortitude. But there are different ways of winning. And I feel we’ve done the big win at Medmerry.”
Andrew Breiner contributed the graphics to this piece.