Government planning policy and the Environment Agency are pushing for more use of sustainable urban drainage systems (SUDS). These use attenuation and retention to slow the rate at which water enters drainage systems, and encourage it to permeate into the ground.
Unfortunately, eciding whether water companies, developers or property owners adopt these remains a thorny issue as no-one wants to take long term responsibility for them. It is an issue which is giving consulting engineers, developers and water companies a headache and pushing up the cost of SUDS.
'It is never going to be cheap to use them as the consultation process is so protracted, ' says Campbell Reece consultant Simon Boots, who has been implementing SUDS for the past 10 years.
Thames Water gulation liaison manager Stephen Evans says that the current framework for adoption is clear. 'We cannot adopt anything that is not legally held as a sewer as Ofwat won't accept it, ' he says. So if a SUDS system can be classied as a sewer according to the 2004 interim code of practice, then the water company is able to adopt it.
But, that still leaves SUDS that are not classed as sewers, such as permeable paving, lter strips and bio retention systems. 'Government needs to re-legislate', says Boots.