Professionals called for an holistic approach to water drainage at the Sustainable Water Industry Group (SWIG) working lunch last week (17 January) under the title "Creating the 'Green' Urban Oasis".
Green versus grey drainage solutions, green walls, roof gardens and Thames Water's £4.6bn Tideway Tunnel (the "Super Sewer") - against a background of rising urban populations, climate change, urban heating and a finite supply of water - were debated by a cross-industry panel at the Roof Gardens in London.
Landscape architect Luke Engleback of Studio Engleback described himself as an "eco-urbanist" and said decisions taken on a macro scale often have an effect on the micro scale.
"I'm a great believer in putting the function back into landscape. The 'bio-philic' way of designing is to put back nature as a functioning part of drainage. There's no single solution. It's a behavioural change."
He shared details of a 6.5ha garden village in Wales that he worked on where the sustainable urban drainage system (SUDS) was stymied by "the message not getting through" to Welsh Water and the client, and highlighted combined sewage and rain drainage systems in towns as a problem.
Sustainable water and low-carbon adviser Cath Hassell of Ech2o Consultants agreed: "We can't continue to put combined rainfall and sewage straight into the Thames. The Super Sewer is the hard engineering solution but we need a soft solution."
One audience member called for a "strategic infrastructure strategy", while another criticised the hard engineering approach, saying that in Philadelphia, USA, green solutions are working well after the city decided that it could not afford to build a new tunnel.
But David Harding from Thames Water's customer and stakeholder engagement team pointed out that this would not be possible because it would take generations to achieve landscape and behavioural changes needed and the legislation necessary for the work needed does not yet exist.
"Thames Water does support SUDS," he added. "We know the Super Sewer will become unsustainable in a few generations just as the Victorian sewers have done. The Government is on the hock with the EU for breaching the Water Treatment Directive. Our strategy is that we need the Tideway Tunnel so we can be compliant before UK PLC is prosecuted."
Speaking after the meeting, Harding said that it is crucial that retrofitting, permeable paving and landscaping solutions are carried out over the next 80 years.
The panel comprised Luke Engleback of Studio Engleback; Cath Hassell of Ech2o, creator of Nickolodeon's Gabi H2O rapping camel videos; Avi Djanogly; garden designer Janine Pattison of Janine Pattison studios; and Zac Ribak, managing director of irrigation and water recycling company Watermatic. Engleback and Hassell gave presentations.