Floods flag need for water-sensitive design

Experts call for retrofitting towns and cities, more tree planting and recognising the value of parks for help with drainage.

Manor Fields: scheme provides community park and sustainable drainage for new housing development - image: Ian Stanyon
Manor Fields: scheme provides community park and sustainable drainage for new housing development - image: Ian Stanyon

The country is currently in the grip of flood fever, with the Government in apparent tailspin after the wettest winter in centuries.

Flooding has been exacerbated by population expansion, urban creep and drainage issues. But amid the emergency response and all the political recriminations, it is easy to forget that this was a foreseeable problem with a number of potential solutions, including water-sensitive urban design (WSUD), a cause that has been championed by the Landscape Institute.

Industry experts are now wondering whether their voices will, finally, be heard. "What's been happening has absolutely brought this issue to the fore," says Landscape Institute president Sue Illman, who has used every opportunity of her presidency to warn of the dangers of not adopting WSUD and the benefits of doing so. She says people are now finally taking notice.

"I think that with everything that's gone on since Christmas it will be very difficult to put this back in the box. We're doing a retrofit scheme in Cheltenham and residents were not trying to understand when we started the project before Christmas. All of a sudden, there's an awful lot of interest."

Landscape consultant Peter Neal agrees. "This particularly dark cloud has the potential to deliver a rather attractive silver lining," he says. "The major flooding affecting large areas of the country highlights the needs to take a more strategic approach because this problem may well get worse in years ahead."

He continues: "We have to look beyond simplistic and knee-jerk solutions such as dredging that may only accelerate and increase problems further downstream. A sustainable approach that works with nature rather than against it is best found by combining the skills of landscape architects, planners, engineers and hydrologists working across entire drainage systems."

Retrofitting towns

Crucially, many say this means not just looking at individual developments but retrofitting our towns and cities, planting more trees on higher ground and recognising the value our parks and urban green spaces have in helping drainage, improving air quality and mitigating the urban heat island effect.

"In urban areas, parks and green spaces will play a central part in this strategy," says Neal. "That is why the Environment Agency is starting to spend serious and wise money in retrofitting parks."

One successful sustainable urban drainage system (SUDS) to have been installed on unloved and crime-ridden open land, Manor Fields in Sheffield, is a good example of what can be done. It was devised by Sheffield City Council landscape architect Ian Stanyon to provide sustainable drainage for a new housing development, at half the cost than building a new sewer, while providing a community park and a wildlife haven.

Stanyon says it has transformed the area, bringing communities together. It also helps to alleviate pressure on the River Don and downstream towns such as Doncaster during high rainfall.

Consultant Dr Sid Sullivan says the Government now has no other option but to take action "to resolve this ugly blight on people's standards of living and health". Flood plains and water meadows should be respected, he maintains.

The Parks Alliance, born from Horticulture Week's Make Parks a Priority campaign and formed by industry experts to stand up for parks, wants to help and is urging the Government to make parks professionals "part of the solution alongside health, environmental and planning colleagues" while warning that floods only exacerbate the ever-decreasing pool of funding for parks as councils look for more money for flood relief.

"We probably hold that missing part of the jigsaw that can contribute to the resolution of this excruciating dilemma for people, their health and the environment," says a spokesman.

International study

A recent report by the International Federation of Parks & Recreation Administration reviewed research on urban green space conducted in Manchester, Leipzig, Munich, Beijing and Nanjing.

With the proviso that the studies used modelling rather than field work, in all five cities scientists found urban parks contribute to storm water management, with various report authors positing the idea that the more green space and trees you have in a city, the less often flooding occurs.

The problem is that in real life, things are rarely simple. After the 2007 floods cost 13 lives and £3.2bn, the Pitt Review recommended a slew of improvements, which led to 2010's Flood & Water Management Act. This does not provide a manifesto for transforming our water use as a whole but it does at least introduce mandatory SUDS to every new development.

Schedule 3 of the act requires all planning authorities to establish SUDS approval bodies, or SABs, to ensure that this happens. But four years on and we seem to be no closer to seeing this implemented. This winter's floods, particularly the plight of Somerset residents, have brought the issue to a head with questions asked in Parliament, troops deployed and Government advisers weighing in on the issue.

Meanwhile, parks remain a non-statutory council service and are losing funding everywhere as local authorities cut back further each year to cope with Government cuts. Economic restriction was also the reason given by the Environment Agency for not dredging on the Somerset Levels.

Committee on Climate Change head of adaption, Daniel Johns says: "Trends in planning, urban green space and impermeable surfacing need to be reversed. The first step is to make sure remaining aspects of the Flood & Water Management Act are implemented. This will allow authorities to plan ahead and build capacity to approve and adopt them. Hopefully the whole system will begin now in October this year."

Before implementation, Defra needs to finalise the National Standards consulted on in 2012 and the guidelines for both planning authorities and applicants. In addition, councils and developers disagree on who should pay to maintain any SUDS created in the long term.

"It's clear that the SUDS requirements need to be introduced with the support of other Government departments, local government and developers, and it has to be done well," adds Johns. "But it's not clear what obstacles remain and how further delay will help."

Community protection

A Local Government Association spokeswoman says councils wanted to see SUDS, which have an important role in protecting communities from floods, in place as quickly as possible.

"However, Government has not yet told us how they will be funded. We need clarification on that and a clear timetable for introduction before councils can get the new SUDS approval bodies up and running."

The Home Builders Federation also says it welcomes the act but blames councils for not being ready. "The absolute crunch issue for us is when it does go live a housebuilder has to have approval before it can start on site. That would be very damaging for us and the Government," says economics director John Stewart. "What's become clear is that the many SABs are not going to be in place in April. The national standards and guidance are also not ready."

However, according to Illman, while some councils are not ready "some have been raring to go for years". She says the national standards negotiations led to the act being downgraded.

"The Government has been trying to get agreement from some of the housebuilders. Issues such as water quality, amenity and biodiversity, which were in there, have been completely taken out," she noted.

"If you engineer SUDS in amenity space they can be attractive features in their own right. You can use things like permeable paving. You can use the green space. You can have a planted strip around your car park."

In contrast, Stewart points out "the point of SUDS is to minimise surface run-off" and adds that green space is not necessary. Subterranean options are the only practical solution for developments of fewer than 50 units, he says.

"There's no spare land on smaller sites. On a bigger scheme there's probably land that we can use. If you insist on an above-ground solution you would end up using a number of dwellings, which has an impact on the commercial viability of the site. Some small schemes won't go ahead at all."

Stewart adds: "What the industry wants to do is work out what is the most cost effective solution within every site."

This apparent Flood & Water Management Act deadlock masks a bigger issue - that SuDS are only one aspect of futureproofing our urban areas. Johns points out that the Committee on Climate Change has "concerns about how planning is being implemented and the regulations enforced",

Despite "the rhetoric" being that there should be no inappropriate development on flood plains - the Pitt Review says this should be the "absolute exception" only when there is no alternative land available - 40,000 new properties were built in areas of significant flood risk over the decade to 2011, he says.

"There are obvious examples of best practice but when we looked in detail it wasn't clear that planning authorities had considered other sites for that development. We are also concerned that Environment Agency advice may not be taken up as much as the Government thinks."

Johns adds that because of climate change a range of different solutions should be examined, including water harvesting, green roofs, urban landscaping and SUDS, a line with which landscape and green-space professionals will be more than familiar.

"We're looking beyond flooding to look at the urban environment from a health and well-being point of view, trying to counteract the urban heat island effects and make sure that there are places that are cooler.

"When we are thinking about SUDS and urban green space we should recognise the wider benefits of it from a wider public heath point of view. Our advice to the Government is to look in the round at these issues, to recognise that it's not just about flood defences. It's about the whole issue - managing extreme heat and rainfall."

With members of the cabinet at loggerheads, a general election due next year and the rain continuing to come down, it remains to be seen whether the Government will listen.

Research review Benefits of Urban Parks

Kazmierczak and Cavan (2011) found areas in Greater Manchester with a large proportion of land susceptible to surface water flooding tended to have less green space.

In a model by Gill et al (2007), also of Manchester, adding green cover reduced stormwater run-off substantially. The authors stressed the important role of mature trees in the water cycle because of evapotranspiration.

Zhang et al (2012) in Beijing found that 2,494cu m of potential run-off was reduced per hectare of green area and a total volume of 154 million cubic meters of rainwater was stored in these urban green spaces.

This almost corresponds to the annual water needs of the urban ecological landscape in Beijing, the authors noted.

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