Over the past few months, the scandal of our sewage-polluted watercourses and seas in the UK has had widespread publicity. The public is rightly horrified that most of our British watercourses are not fit for swimming in and that untreated sewage spills have occurred so often – but not all of us are aware that we can be contributing to the problem.
Our “combined” sewers collect both our foul sewage and our rainwater – and most of our older towns and cities rely on this type of drainage. Newer developments have a “twin pipe” solution, with a separate foul sewer and surface water sewer, and this design usually does not cause trouble – except for misconnections. So, by simply reducing the amount of rainwater entering the combined sewer from our properties we can help reduce the overall problem.
But how can we do this? Water can be moved around but is difficult to destroy. If nothing else, emptying your water butt prior to a storm event means that less water will be flowing down the drain during the rainstorm – and there are many other opportunities now available to landowners.
The Government recently announced that it is minded enacting Schedule 3 of the Flood and Water Management Act 2010 in England; Wales did so in 2019. This requires most new build developments to submit a Sustainable Drainage System (SuDS) proposal to the SAB (SuDS Approval Body) for approval before construction commences. This also removes the automatic right to connect new developments to the mains drainage system, thus forcing developers to consider SuDS early in the design process.
So, what are SuDS? Sustainable drainage systems are nature-based solutions that slow water down, clean it up and bring other eco-system benefits. These features can be used on their own, but more often in a series of features known as “SuDS Trains” to maximise effectiveness. In addition to the attenuation provided by the soil, plants and trees take water from the ground via evapotranspiration through their leaf structure, reducing the water flowing through the system.
The inclusion of SuDS at the master planning or development site planning stage has a significant effect on the viability and cost-effectiveness of SuDS integration and the ability of SuDS to deliver multiple benefits. Master planning provides a strategic approach to consider the (sometimes competing) requirements for development. SuSDrain
Whilst introducing SuDs to developers gently, it is widely considered not to have worked; many developments have poor sustainable drainage solutions which can even be detrimental to the value of the properties. The new legislation will help improve the delivery of these essential features, to all benefit.
GreenBlue Urban has long advocated the early intervention of landscape professionals in the design process: Schedule 3 will further enhance their status as vital designers of critical infrastructure.
Our very own Howard Gray was delighted to introduce Laura Bigley, Principal Flood Risk Manager at Lancashire County Council and Chair of the Association of SuDs Authorities, during our recent trees-stormwater podcast, which was also aired as part of a webinar for the Landscape Institute. They discussed preliminary surveys to dictate topographical opportunities for SuDS, using rainfall data to calculate volumes of water for attenuation and of course the use of green infrastructure to attenuate and treat rainwater.
GreenBlue Urban continues to innovate and manufacture solutions such as the ArborFlow SuDS-enabled tree pit. The HydroPlanter range of adaptable rain garden solutions makes implementation simpler and cheaper, creating healthy urban spaces in harmony with nature.