8 minute read
Redirect the flow
1. Sue Illman photographed at the Landscape Institute Awards 2023.
© Andrew Mason
Josh Cunningham
During her tenure as President of the Landscape Institute, Sue Illman, together with representatives from 12 other organisations, wrote to the then prime minister David Cameron, calling for long-term planning to prevent the devastation caused by flooding. Published in the Daily Telegraph on 20 February 2014, the letter became a frontpage news story, and was picked up widely in the media.
The letter was sparked by a long winter of flooding across the UK – from the Somerset Levels to the Thames Valley and to Tyneside. In the media that Sue was soon to weigh in on, aerial shots of flooded towns and villages joined images of devastated infrastructure facilities, and army personnel lugging sandbags through floodwater. 'Elderly and vulnerable people, who couldn’t get out of their house when it rained,' remembers Sue, who lives close to some of the worst affected areas. 'And if they were already out of their house when it started, then they couldn’t get back in. It was horrible.'
In the decade since, flash flooding has again hit the UK in 2016, 2019 and 2020, while hugely devastating floods have occurred internationally in Pakistan, China, India, and most recently across the Mediterranean, with thousands killed in Storm Daniel. With climate change thought to be increasing the intensity and 'supercharging the rainfall'² of such storms, keeping flood prevention at the top of the political agenda is paramount.
Sustainable Drainage Systems (SuDS) provide a nature-based solution to water management. Rather than concrete culverts and subterranean pipes, set within the hard urban landscapes that have come to dominate many built environments, SuDS offer the opportunity to use living systems of soil and vegetation to manage water. Providing exactly the kind of integrated solutions that landscape architects are known for, these natural solutions reduce peak flow rates, provide water storage capacity, and filter out pollutants.
The result of this is reduced surface water flooding, improved water quality, enhanced biodiversity, and a positive impact upon human health and wellbeing. Or, as Sue says, to keep it simple, 'Its four things: quality [of water], quantity [of flow], amenity [for people], biodiversity [for the planet].'
Sue has spent her career as an ambassador for this cause. During her time as President of the LI, she oversaw a range of LI publications on SuDS and green infrastructure. As a consulting author for the Construction Industry Research and Information Association (CIRIA) she has been involved in writing a range of SuDS manuals, while in practice at IllmanYoung she has delivered both new and retrofitted SuDS across the UK.
'It’s all about nibbling,' says Sue, reciting the catchphrase she coined to bring together all aspects of SuDS delivery – from the gradual way that nature reduces the flow of water as it forms a course, to the incremental way that practice has made inroads through the proliferation of SuDS in the UK. 'It’s about managing water as close as possible to where the rain falls,' Sue continues, 'whether it’s permeable paving or wetlands, bioretention planters or rain gardens, whatever we can do to maximise the benefits throughout the whole site.
Back to the source
Sue’s first work in this field was the result of a Knowledge Transfer Partnership (KTP) between her practice and the University of Gloucestershire in the late 2000s, which involved research on how green systems purify water. 'The more research we did, the less we understood about how to implement our findings into practice. With some nibbling, we just went out and tried things. We’d talk to the architects and engineers on projects and slip our ideas into the design.'
Meanwhile, a similarly entrepreneurial approach in the city of Portland, Oregon, had led to landscape architect Tom Liptan becoming a pioneer for SuDS, in a city trying to manage its industrial activity with the Willamette River.
By 2007, Liptan was leading Portland’s ‘Green Streets’ project, which saw the implementation of raingardens, roadside swales and street planters across the city. 'Crucially, they had to demonstrate that it was cheaper than a conventional system,' says Sue, 'which they did [...] In the UK, it’s the cost of land which gives SuDS a reputation for higher expenses. It does depend on the site and project, but even when SuDS are more expensive, it isn’t by a lot. And when you design it properly, it doesn’t have to take up more land.'
With this issue firmly in mind, Sue co-authored ‘Sustainable drainage and new housing developments’, an article for the University of Sheffield. Drawing on research carried out over a few years, it found that the only realistic solution to such market-driven decision making is through policy. 'Four big developers were asked their opinions on SuDS, and they basically said, "If we’re bidding for a site and [SuDS] are more expensive, we’re not going to do it. Give us the legislation so that there’s a level playing field for everybody, and then we can bid."'
This was not a new revelation to Sue, and she explains that it was this need for policy that had prompted the industry letter to the prime minister she had coordinated back in 2014. 'They did enact the 2012 Flood and Water Management Act, but it was dumbed down at the last minute. We think they were lobbied by housing developers at that time,' Sue says, but things have changed a lot now.
Still, a new version of the Flood and Water Management Act is expected to be rolled out in 2024, which will mandate (almost) all new developments to use SuDS instead of conventional drainage systems. 'If the legislation as currently drafted makes it through the parliamentary system intact, then there should be real change; but will it?' asks Sue. 'Recent flooding issues help keep the subject alive, and there is now a better all-round understanding of the necessity to manage water better.
Whatever the outcome, there will remain the conflict between those offering systems that manage water underground versus "SuDS on the surface".’ Ultimately, there is likely to be a need for both, but the latter offers so much more.
Sue maintains that progress will be about working with other professions – engineers, architects, and others –and thinking about drainage budgets in a different way. 'Sticking a pond at the end of a pipe isn’t SuDS – we need to use it to create swales, wetlands, planters too.' It’s about creating place, she says, 'and when you integrate water management and placemaking, you get benefits across the board – from health and wellbeing, to economy, to biodiversity. As landscape practitioners we can respond to the context of a local site and situation. SuDS are just one part of our toolkit, and we need to do what we can to make it our everyday. Let’s start by making the most of the new biodiversity net gain legislation to deliver SuDS.'
However, when thinking about the future, it is difficult for Sue to reconcile the seriousness of the situation with the current level of proactivity in government and parts of the industry. 'We understand that it’s going to get a lot worse. I think DEFRA looked at what they saw was the most extreme scenarios to plan for, and decided that at this point it would be too difficult to deliver policy that demanding. But they are envisaging those scenarios,' she says, 'and we will need them in the relatively near future.'
'Why are we building problems for the future? Because it "costs more" now? That makes me quite angry, and that’s why we need to just get out there and do it,' Sue implores us, and the many built environment professionals for whom designing and managing places is core. 'Tell your clients, train your clients. Train your fellow professionals. Be subtle if you need to be, but be an advocate.'
And of the SuDS legislation due to come in next year? 'We need it to be good,' Sue says. 'And then we need them to make it better.'
It seems there is a lot more nibbling to do.
Recent flooding issues help keep the subject alive, and there is now a better all-round understanding of the necessity to manage water better. Whatever the outcome, there will remain the conflict between those offering systems that manage water underground versus ‘SuDS on the surface’.
