The government is out to consultation on how to implement the sustainable drainage element of the Flood and Water Management Act.
This is viewed as positive by the housebuilding industry, following the lobbying efforts that have been made.
The potential scrapping of the sustainable urban drainage systems approving bodies (SABs) before they have even been created – thus providing more flexibility to how developers implement SUDS – clearly demonstrates that the industry is in a position of strength and influence right now.
This is thanks to a combination of the housing shortage, an upturn in housebuilding, the success of Help to Buy and the modest improvement in the economy.
At a recent conference, the Department for Environment, Food and Rural Affairs made a presentation on this issue that correctly highlighted the effect of the Pitt Review’s recommendations on this.
It did make me reflect, however, that this report was commissioned as a result of some of the worst flooding events in recent history, with towns and communities devastated by the effects of severe rainfall and rivers bursting their banks.
There is no doubt that changes to our climate are making such events more frequent, but I still can’t convince myself that SUDS can make much of an impact.
“I doubt SUDS will significantly contribute to the prevention of flooding of watercourses and existing drainage systems”
While I believe SUDS are an effective and environmentally beneficial method of surface water run-off management, I doubt this will significantly contribute to the prevention of flooding of watercourses and existing drainage systems.
When floods do occur the housebuilding industry is accused of reckless development and we see pictures of modern estates submersed in water. This is caused mainly by existing systems failing, not the development itself.
When these schemes were granted permission, how was the planning authority and statutory consultees convinced the site was not at risk of flooding?
For many years new developments have been required to undertake flood risk assessments and then implement a drainage strategy that restricts surface water runoff to greenfield rates or better.
Solutions may have been SUDS-based or an engineered solution such as tanks.
Often these engineered solutions are not considered SUDS or ‘green’, but they do contribute to controlling run-off, can often be adopted by the sewerage undertaker and are maintainable.
“Often these engineered solutions are not considered SUDS or ‘green’, but they do contribute to controlling run-off, can often be adopted by the sewerage undertaker and are maintainable”
Does this not tick a box for Pitt? Should Defra reconsider its stance and leave developers and planning authorities to agree drainage solutions?
Perhaps a large deep attenuation basin could be swapped for a buried tank, constructing a play area over the top, if that is what would really benefit a community.
Should we perhaps make the restriction of run-off rate more onerous? If the developer could determine the best solution to deliver this, perhaps the industry would be in agreement.
Holding back flows more would reduce the impact downstream, reducing flood risk.
Finally, why not make rainwater harvesting compulsory for all developments? Whether a factory, house, school or football stadium, they all have toilets and other facilities that can use harvested rainwater.
If it was mandatory, then it would be a level playing field.
Eddie Mewies is managing director of M-EC Consulting Engineers