黑洞社区

There used to be a few things you could count on from a British summer 鈥� the early exit of our contenders at Wimbledon, bank holiday travel chaos and the inevitable hose-pipe ban. Although the first two may still be true, this year it has been the abundance of water that has made the headlines. The floods at the end of June can be partially attributed to the changing climate, which is bringing us warmer and wetter weather. Some of the devastating effects can also be partially blamed on poor water management.

鈥淥ur existing drainage simply washes pollutants into water courses and when there鈥檚 a downpour it has a flushing effect,鈥� says Phil Chatfield, policy officer at the Environment Agency. 鈥淲e need to go back to something closer to the natural state, or our urban areas will be overwhelmed.鈥�

This is why the Environment Agency, the government and local authorities are keen to promote the use of sustainable urban drainage systems (Suds) on new developments. Rather than removing water from a site as quickly as possible, Suds have three main aims: to reduce the amount of water flowing from a site, to manage its flow so that sudden influxes are avoided and, where possible, to clean it along the way.

The use of such schemes is recommended in planning guidance. PPS25 directs planners to encourage the use of Suds and PPS23 shows how they can help to control pollution. Then there is the Code for Sustainable Homes and Part H of the 黑洞社区 Regulations, both of which are concerned with water management.

But despite this recognition of the value of Suds, they are still not being included in many new developments. In the past, this has been put down to ignorance about how they work and the industry鈥檚 reluctance to adopt new practices. Chatfield points out that this is partly because there is no one-size-fits-all solution: 鈥淯sing Suds means designing something bespoke 鈥� the way sustainable drainage will work on each site is different.鈥�

However, these barriers do seem to be breaking down. 鈥淚n my experience, most consulting engineers are aware of Suds and of how to design them. If they鈥檙e not, they know where to get that information,鈥� says John Howe, general manager of precast concrete paving and kerb association Interpave. 鈥淭hey will also be aware 鈥� as will architects and developers 鈥� that the government鈥檚 planning policy is saying we must have Suds.鈥�

So if the information is getting through, what鈥檚 the problem? Rupert Lodge, partner at engineer Max Fordham, suggests that developers are baulking at the price. 鈥淐lients hate it because sustainable drainage is expensive but you have to do it 鈥� why should somebody downstream suffer because your scheme is well drained?鈥�

However, the overall picture seems more complex. Howe and Chatfield point out that Suds are being increasingly used in developments that remain in private ownership. This is because, in these cases, there is a single point of responsibility.

But this is not always the case. 鈥淗ousing is a different kettle of fish because developers build houses and their infrastructure and then pass them over to the local authority,鈥� says Howe. 鈥淭hat鈥檚 where Suds are falling down. Who is going to take on their maintenance and liability?鈥�

This is the main barrier to the adoption of Suds. The management of water is split between utilities companies, the Environment Agency and councils. Once you throw a developer into the mix, it is not clear who is required to maintain the systems.

Defra is aware of this problem, and has set up urban drainage pilot schemes. The aim is to get stakeholders together to see whether they can manage the water in a holistic way.

Some councils are taking the initiative themselves 鈥� Oxfordshire is cited by many as one of the most progressive councils in its approach to drainage. It is using permeable paving (see right) in some of its developments and, importantly, it is designing schemes so that these are isolated from the services to avoid maintenance problems. Chatfield says that Bristol and Edinburgh are considering similar schemes.

But for many the pilot schemes do not go far enough. The impetus for real change could come in the form of the EU鈥檚 water framework directive, which requires a reduction in the pollutants entering rivers. In order to comply, the country鈥檚 rivers need to achieve a 鈥済ood鈥� status by 2015 鈥� currently, one in seven rivers in urban areas is of poor or bad quality. Suds are seen as vital to achieving this and Defra is expected to launch a consultation soon on measures to reduce pollution. These could include rules on which organisations will be responsible for Suds鈥� long-term maintenance.

If this happens, the last barrier to the widespread use of Suds would have been removed. As the recent floods show, such systems are more necessary than ever. As Chatfield says: 鈥淚n lots of places we鈥檝e buried our rivers and lost contact with the natural environment and then we鈥檙e very surprised when it comes back to haunt us.鈥�