Blog

Paul Shaffer, CIRIA

Last week saw the official launch of Greener Grangetown in Cardiff. CIRIA’s susdrain project was lucky enough to have a preview in September, when we had a tour of the ground-breaking scheme.

It’s an ambitious £2 million partnership project between Dŵr Cymru Welsh Water, Natural Resources Wales and the City of Cardiff Council (who was the main client for the project) to deliver a sustainable drainage system (SuDS) and transform the quality of places and spaces in an inner city area. The multi-disciplinary design was led by Arup.

The retrofit scheme delivered across 12 residential streets is probably the largest in the UK. It uses an array of SuDS components to capture, treat and divert rainfall from the sewer system directly into the River Taff. Previously the rainfall entered the sewers and was pumped eight miles away to a treatment works where it was then discharged into the sea.

Before our tour in September, Ian Titherington, from the City of Cardiff Council and Chris Ellis from Arup provided an overview of the scheme outlining the importance of the community (the presentation is here and there’s also a video explaining the scheme). So as well as the delivery of SuDS and the energy savings it was clear that multiple benefits was at the heart of the project.

The project has an impressive tally of statistics:

• 42,480m³ of surface water diverted from the combined waste water network.
• The creation of an additional 1,600m² of green space (the equivalent of 4 basketball courts).
• Combining rain gardens and traffic calming creates Wale’s first ‘bicycle street’
• Improved biodiversity – 108 rain gardens, 135 new trees (19 different species) and thousands of shrubs and grasses planted.
• New urban infrastructure including 26 new cycle stands, new seating and bench areas.

Walking around the area the impact of the new rain gardens, trees and landscaping is clear to see (pictures of the scheme are here). As well as reducing the volumes of rainfall that needs to be treated it is an attractive and lush environment to walk through. Anecdotally, house prices have jumped in value, (whether this is ultimately beneficial for the community or not remains to be seen). The improvements to place making, biodiversity and recreational opportunities are obvious and have started to be realised.

Feedback from those on the susdrain tour suggested there’s recognition that the ambition has been rewarded with an impressive scheme, not just in terms of scale but more importantly in terms of benefits. While there were some reservations about the potential challenge of maintenance and how the hydraulics and drainage works in reality, everyone recognised that the drainage improvements are probably inconsequential to the improvements to place-making and the value for the community.

Greener Grangetown is a fantastic example of partnership working and the value of Champions like Ian Titherington. Maybe it is because Ian lives in Grangetown, but he’s established and shared a vision for the area that delivers so much more than just drainage. The ambition of the project is to be applauded, it has certainly delivered a better quality of place. Maybe the improvements to surface water management and sewer infrastructure resilience are a by-product, rather than the primary function, and maybe that is how we should promote sustainable drainage in the future? What do you think?