Getting the value out of SUDS

A conference on stormwater management gave industry experts the chance to share their experiences of managing water in the urban environment. Kevin Stanley reports

In his opening address to the Stormwater Management Conference held in Solihull in May by British Water and Hydro International, chairman Professor Richard Ashley of Sheffield University asked the key question of the event: "What about quality?", he queried. "SUDS are the answer to stop flooding, but we must also look to add value by improving water quality and storage."

The speaker panel was made up of industry experts from Defra, the Environment Agency and the Construction Industry Research & Information Association (CIRIA), as well as leading academics and consultants. In his keynote address, Professor Tony Wong from the Centre for Water Sensitive Cities in Melbourne, Australia, delivered a presentation explaining what could be achieved by the implementation of blue and green corridors in urban areas.

"By bringing nature back into the city through a network of green and blue systems we have a much more natural way of managing floods and a more natural way of managing the relationship between the human habitat and the natural environment and ultimately the ecosystems services that those natural environments in fact provide us," he said.

The difficulty of retrofitting SUDS into existing urban environments was investigated in depth. Speakers said that it was crucial to secure early and effective engagement between the stakeholder organisations and disciplines in order to unlock potential opportunities.

"Retrofitting requires the involvement of numerous disciplines to ensure that the chosen approach improves surface water management, fits in with the existing urban design context and is accepted by the community," says Paul Shaffer, associate, of CIRIA. "These disciplines would need to work together to innovate and may typically include drainage and highway engineers, urban designers, landscape architects as well as social scientists or communication experts."

Bob Crabtree, business development manager - environment management, of WRC said: "Retrofitting SUDS is difficult in the middle of a city that's been around for a few hundred years, but it's not impossible. Quite often people focus on SUDS in terms of new developments but existing urban areas are just as important."

He added: "We need to do something different. It's important to join up the resources of drainage and urban planning. They've not been going in the same direction."

Sue Illman, of Illman Young Landscape Design brought attention to the problems with cost if sufficient space has not been left. "Then the choice of SUDS components is often limited to hard solutions," she said. "In urban situations or regeneration projects we may need to consider removing buildings to provide sufficient space."

Illman celebrated examples of best practice in Malmö in Sweden and Portland, Oregon, in the US, where the public was involved in the projects. "Installations have lead to dramatic improvements in alleviating flooding problems, whilst also doing so in an attractive and creative way, and this has really engaged the public in a positive way," she said.

Shaffer agreed that SUDS needs to be sold on the broader benefits on top of flood risk. "SUDS components and schemes tend to be designed to meet certain performance criteria around flood risk management, water quality and improving amenity and biodiversity, commonly referred to as the 'SUDS triangle'," says Shaffer.

Retention
"Sustainable drainage schemes will use retention, infiltration and attenuation to help reduce the volume, frequency and flow rate of surface water runoff, while gully and pipe based systems pass all this flow downstream."

He added: "With the development of Ecosystem Services and Green Infrastructure, the opportunities for SUDS to deliver multiple benefits is becoming recognised, such as the regulation of flooding, pollution and urban heat islands, as well as the provisioning of aspects like recreation and community cohesion."

Jeremy Benn, of JBA Consulting, warned that in practice SUDS is likely "only to reduce flood risk marginally, and at lower return periods, and will not provide the levels of flood protection service required of modern developments."

He believes that "if the wider benefits of water quality improvement, water recycling and environmental improvement are considered, then SUDS starts to really make a difference."

A heated discussion surrounded the topic of the difficulties of involvement with SUDS Approving Bodies (SABS). "Whilst we still don't know exactly how the local authorities are going to run their SABS, we
are utterly reliant on the National Standards to ensure that we can design creatively knowing that it will be acceptable," said Illman. "What we do know is that a simplistic engineered SUDS approach is not the required standard.

Dumbing down the requirement to equate quality, quantity and biodiversity/amenity would be very retrograde."

Yet delegates and presenters agreed that sustainable urban drainage could be achieved with the correct planning, joined up working and understanding of the solutions. Shaffer suggested that SUDS is not really too difficult in a practical sense, but that it is people's thinking that is difficult to change. As academics, designers and contractors petition to implement improvements to the UK's approach to urban drainage infrastructure, it is clear that great inspiration can be drawn from overseas.

"The approach being taken in Australia, where SUDS is considered not only the norm, but essential, and where excellent creative design works hand in hand with water management, is inspirational," says Illman.

Which leaves perhaps the most pertinent question, "So how do we achieve that mindset here?"

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