The government’s decision to mandate the inclusion of sustainable drainage systems (SuDS) in all new developments has raised a number of questions – around a significant skills gap, the sharing and funding of maintenance and the need for flexibility in regulation.
The move by the Department for Environment, Food and Rural Affairs (Defra) last month to enact Schedule 3 of the Floods and Water Management Act has been warmly welcomed across the water sector. For years companies have campaigned to remove developers’ automatic right to connect to existing sewer systems as well as mandate SuDS. But as the policy is being developed – after sitting dormant for years – experts fear there are more questions than answers about its implementation.
“For me the biggest risk around Schedule 3 at the moment is around resources and skills,” Jonathan Glerum, flood risk engineer at Anglian Water told the Wastewater Conference last month. “Where are we going to find 300-odd SuDS engineers to populate all the SuDS Advisory Boards (SABS) in the next 18 months? They just don’t exist at the moment.”
SABS will be responsible for approving connection applications to a local sewer.
“We’re really pleased Schedule 3 has been moved forward, we have been campaigning for years to remove the automatic right to connect,” he added. “But it shifts the risk slightly if the SAB has responsibility.”
Maintenance matters
Rachel Wray, nature-based solutions lead at Atkins and formerly SuDS technical specialist at Yorkshire Water, aired her concerns that maintenance could end up being side-lined in the “often reactive work” of the water sector. “There is a learning curve here,” Wray said and suggested a national database of all schemes, with responsibilities laid out.
Northumbrian Water’s sustainable drainage manager Richard Woodhouse agreed maintenance after installation could be problematic. He explained Northumbrian writes contracts for each retrofit installation, including responsibilities of all partners for asset upkeep.
Although Woodhouse admitted these agreements could be complex, he stressed that getting it right from the outset was ultimately beneficial.
“It comes down to who holds the risk,” Woodhouse explained. “If it’s not maintained and not doing what it was designed to, and someone has a pollution incident or flooding event, then who holds responsibility to pay to fix it?”
Resolving maintenance considerations will never be “a one-size fits all” approach, Glerum advised, because levels of community engagement will always vary as will willingness or ability to be involved.
In non-domestic settings, he said “grown up conversations” with the Highways Authority or local government about who will manage assets and who crucially who pays, must be held.
“The key thing is thinking about the broader benefits you get from blue-green infrastructure and how can we use that broader benefit to leverage funding for the long-term maintenance,” Glerum said.
Affordability concerns
Despite the hurdles, companies remain keen to make green infrastructure a much bigger feature of their investment programmes. However, Woodhouse cautioned that the costs of SuDS was up to eight times higher than grey solutions for some applications Northumbrian was exploring – such as addressing storm overflows.
The least-cost version would involve pouring a lot of concrete, he explained, but stressed that was not the company’s preferred approach.
Likewise at Anglian, Glerum said the SuDS approach was “absolutely the way we want to go”, but cost remains a crucial decider. A challenge here is traditional supply chain partners working with the sector have spent decades focused on grey infrastructure.
“None of us have that experience at the moment,” Glerum said. “So there will be uncertainties there that bring costs.”
He suggested regulation needed greater flexibility to let companies pursue green infrastructure to address pollution problems.
Without that, he mused that well-known but less environmentally-friendly approaches would remain the default to achieve targets in the limited time available.
“A far more flexible approach will be needed in terms of regulation,” Glerum said. Through the water industry national environment programme (WINEP) the sector hopes to see more room to manoeuvre.
“We all want to go down this route, it’s about whether the drivers at the moment are allowing us to do that.”
Addressing environmental concerns such as combined sewer overflows rapidly with prescribed targets for spills per year fails to address water quality, Woodhouse warned.
“The Storm Overflow Discharge Reduction Plan has nothing to do with quality,” Woodhouse said. “There is an assumption fewer spills will lead to better water quality – and it probably will, but if it was more flexible you would have more opportunities for sustainable solutions that lower spills across a catchment.”
Jo Bradley, director of operations at Stormwater Shepherds, described the plan as “a very complex problem that has been brought down to a perhaps overly simple solution”.
She agreed that the plan did not distinguish between overflows that cause more or less harm than one another but welcomed it as “driving us all in the right direction”.