Sustainable urban drainage systems (SUDS) are being created all over London, despite the Government's failure to progress the Flood & Water Management Act, a forum has heard.
The Sustainable Water Industry Group's latest working lunch, held in the capital last week, discussed the topic "protecting our cities from severe weather".
Haringey Council flood manager Derek Drew-Smith told delegates at the event that we can no longer rely on Victorian engineering to deal with surface water run-off. But he expressed his frustration that schedule three of the Flood and Water Management Act 2010 has still not been implemented.
The act requires planning authorities to establish SUDS approval bodies to ensure that all new building schemes include SUDS. However, it has got bogged down on the issue of who should pay for maintenance.
Drew-Smith also bemoaned the fact that under the act grey rather than green SUDS are allowed - "a quick fix for developers". He added: "Tank schemes are the developers' choice. They do nothing for water quality or biodiversity and will need to be replaced.
"Imagine coming back in 20 years' time to dig up a car park. It will be a nightmare for us. If there's anything we can do to discourage developers from doing this, we will."
Despite this, Drew-Smith said "there is no choice but to change". London is attracting an estimated 100,000 new residents every year while an area the area size of Hyde Park is paved over or built on during the same time period, he pointed out.
"We can't keep improving the existing pipe drainage. There's not enough money to build a big enough pipe for the job." Pooling resources in partnerships such as Green Streets Haringey - an alliance including the council, Thames Water and charity Thames 21 - is one solution, he suggested. It is currently building a rain garden in Boyton Road in a "quick win" pilot scheme while other sites are identified.
However, Drew-Smith said the project is helped by being close to council housing. Similar schemes in other areas have been resisted by some homeowners.
Working lunch Successful SUDS examples
Consultant ecologist Gary Grant of Ecosystems told the working lunch: "We're running out of excuses," but said most current guidance is "Victorian thinking".
He shared examples of successful sustainable urban drainage systems such as a city-wide retrofit in Portland, Oregon, USA, on an operating theatre that reduced air-conditioning costs and tree pits in Stockholm, Sweden.
Some people have uploaded the knowledge gained onto the internet for others to use, he explained. "We don't need to reinvent the wheel, just adapt. The Swedish scheme has already been translated into English. Now we just have to translate it into British contractor."
In the UK, Transport for London is piloting a scheme involving the installation of lightweight living roofs at Underground depots and green roofs have been added to the Flora Gardens estate in Hammersmith, west London.
Grant advises businesses improvement districts, which he said are increasingly keen on investing in the measures. "Often money is spent on traffic calming. That's the opportunity to get some money and spend it on soft interventions."