Build SuDS into developments – not bolt them on

Paul Shaffer, Director projects, CIWEM

CIRIA has recently released Enabling development — Getting SuDS right from the start, supported by a brief animation. It’s a short, practical guide with a compelling message: if we want sustainable drainage systems (SuDS) that add value, we can’t treat them as an afterthought, by trying to bolt them on to a development layout – we need to build SuDS in from the start.

We at CIWEM welcome this addition to the suite of SuDS guidance and are happy to endorse it. We’ve been championing SuDS, or Sponge Cities for decades and through the Enabling Water Smart Communities (EWSC) programme (funded by the Ofwat Innovation Fund), we’ve been exploring the benefits of high-quality SuDS. CIRIA’s new resource gives the industry a clear way to deliver these multiple benefits through early and integrated SuDS design that creates better places and improves water resilience.

Why timing changes everything
Drainage left to the end often means underground tanks, deep pipes and underused ‘bomb-crater’ basins, often called “pipe to pond”, or “pipe to pit” schemes that may (if you’re lucky) tick a few boxes but deliver little else. When SuDS are considered right from the start, they can shape the masterplan: green streets with rain gardens, use swales as wildlife corridors, create attenuation spaces that double as play and community amenity areas – not to mention the dual use of permeable parking.

EWSC’s forthcoming research will highlight this. We’re comparing the benefits and costs of “pipe to pond” SuDS with high-quality SuDS that align with good practice and the national SuDS standards published earlier in the summer. Early, integrated SuDS design can cut capital cost, reduce long-term maintenance, maximise available land and increase development value. The proposition for managing rainwater where it falls and a national rainwater management strategy takes it even further. Suggesting rainfall and runoff should be treated as an asset that can be harvested, easing pressure on potable water supply and cooling urban spaces.

The CIRIA guide connects directly to this thinking. It shows where in the process SuDS should be part of conversations, i.e. site allocation, land promotion, acquisition, site appraisal, pre-application — and suggests who needs to be in the room. It’s practical about stakeholder engagement and risk reduction, while keeping sight of the bigger prize: places where drainage works with the site, not against it.

Clear tools to share and use
Enabling development — Getting SuDS right from the start is concise enough to be used early, by non-specialists as well as drainage engineers and landscape architects. The animation shares the story visually, perfect for quick conversations with colleagues to inform the SuDS design and the vision for the development - demonstrating the art of the possible!

What’s next
We should celebrate the release of these outputs, it’s also part of the jigsaw for the next phase for promoting SuDS. The Enabling Water Smart Communities project will soon publish evidence to strengthen the business case for sustainable drainage, including perceptions of value and comparisons of benefits and costs. CIWEM’s broader future focus on spongier cities (SuDS under a different guise) and CIRIA’s progression of the Rainwater Management Platform will build on that, giving planners, developers, designers, engineers and landscape architects a coherent framework for water-smart growth.

Together, these efforts can move us beyond compliance and towards places that are greener, safer and more liveable.

For now, the call to action is simple: download the guide, watch and share the animation, and bring SuDS into your first discussions on developments. The earlier SuDS are considered, the more they provide – for developers, for communities and for the environment.