Warning over drainage system standards

Clevedon, UK - Government plans to enforce widespread application of sustainable drainage systems (SUDS) across England and Wales through the introduction of new national standards could do more harm than good, warns Alex Stephenson, director, Stormwater, Hydro International and chair of the British Water SUDS group

According to Stephenson, misunderstandings about the nature of sustainable drainage systems, combined with insufficient funding for local authorities to implement the proposals effectively - may pose significant barriers to achieving widespread adoption.

Under the Draft Flood and Water Management Bill issued for public consultation last Tuesday, developers will no longer have an automatic right to connect to public sewers. Instead they will need to seek approval for sustainable drainage systems from new SUDS approving bodies to be set up within local authorities.

The new national standards will provide the basis for approval, adoption and connection to the public sewer and the SUDS approving body will be required to adopt and maintain the majority of surface water drainage systems within the public realm. The Government is also proposing that developers are required, in some cases, to deposit a financial bond with the SUDS approving body, pending satisfactory completion of a SUDS project.

“Looking at the bill, there’s a real concern that the Government may be looking through rose tinted spectacles in its definition of what SUDS means. To achieve proper adoption will mean tackling deeply embedded misperceptions about the nature of SUDS being closely associated only with ‘natural’ or soft solutions such as swales, ponds or wetlands. Otherwise many projects will be stopped in their tracks as being unworkable before they have even begun.

“It will be vital for industry to work closely with Government to ensure sensible provisions within the new national standards that enable both soft and hard engineered storage and treatment technologies to be used as appropriate to deal with polluted stormwater runoff and to slow flood waters down before they enter the sewers.

“Giving local authorities new powers to assess and manage local flood risk is the right way forward and they are keen to embrace the opportunity for stronger leadership. But there has been widespread concern that the move will be ineffective unless the Government provides more money to establish local authority flood engineers.

“Building the adequate technical knowledge and engineering expertise will take time, recruitment, practical guidance - and a significant amount of education about the nature of SUDS. This is necessary both within the Environment Agency in its strategic guidance role and within the new SUDS Approving Boards. It’s critical that work starts now to prepare for these changes, rather than waiting for the bill to become law.

The Flood and Water Management Bill has been drafted in response to the review carried out by Sir Michael Pitt following the devastating floods of 2007. Two thirds of the flooding was the result of surface water runoff. More than 50,000 properties were affected, leading to a £3 billion insurance bill. The flooding highlighted major shortcomings in the infrastructure and management of surface water drainage in the UK.

“It’s more than 15years since Hydro International published ‘Urban Drainage – The Natural Way’ highlighting the importance of Source Control and Sustainable Drainage (SUDS). The guiding principal of SUDS is to mimic as closely as possible the environment prior to development and deal with surface water as close as possible to the point of falling.

“The new national standards should embrace a ‘best management’ approach using the full SUDS ‘toolbox’ of techniques to use the most appropriate for both new and retrofit applications, selected from both natural methods and proprietary technologies, including underground infiltration, storage/attenuation and treatment devices. “