It appears that there’s a perception within Westminster that Sustainable Urban Drainage Systems (SuDS) offer a magic wand approach to sustainable water management and will undo all of the issues we have faced in recent years with flooding and the contamination of watercourses.
The focus and recent trend has been to promote the use of above ground solutions, such as balancing ponds, swales and reed beds and use the natural topography of the land to deal with surface water run-off and excess stormwater.
This viewpoint doesn’t go anywhere near far enough in terms of the actions and requirements needed to successfully achieve a good standard of sustainable water management.
By focusing too much on above ground solutions, we run the risk of exposing gaps within the industry in terms of the experience and expertise to design and build these soft SUDS solutions to appropriate standards.
Do we have the necessary number of designers, specialist contractors and groundworkers with the appropriate knowledge to implement above ground drainage solutions?
The truth is, if the appropriate solution isn’t used then the systems will fail and flooding will occur. We have seen good direction and guidance come from CIRIA, but this still leaves the industry with a potential gap in terms of the practical design, build and maintenance aspects of soft SUDS solutions.
There aren’t many above ground drainage schemes within the UK, so therefore there is the danger that Government is pushing the use of these solutions without the relevant experience within the industry to implement the appropriate elements.A holistic approach to water management is needed to ensure designers and engineers can implement the most appropriate solution for a particular project. The government’s current stance on drainage strategy appears to rule out below ground drainage solutions in favour of soft SUDS, without taking into consideration its effect on other policies.
For example, Planning Policy Statement 3 calls for housing densities of 30 dwellings per hectare, which in practice would be difficult to achieve if engineers and contractors followed the recommendations set by the government’s Future Water document, due to the land take required for an above ground soft SUDS solution.
This disconnect between two sets of Government recommendations creates a degree of uncertainty over whether a hard or soft SUDS solution is more appropriate.
The use of above ground, soft SUDS solutions on brownfield, inner city sites is just not practical and a complete tool kit must include above and below ground drainage solutions.