With year-on-year increases in average temperature and rainfall across the UK, it’s now more critical than ever that infrastructure can withstand growing pressures. Here, Martin Lambley of Wavin, explains how housebuilders can mitigate the impact of flooding and futureproof their projects.
Climate change is making our weather patterns more extreme and leading to more frequent and intense rainfall throughout the year. This is adding pressure for those operating within an increasingly volatile housing market, with a 2022 report from the National Infrastructure Commission estimating the number of English properties at high risk of flooding from heavy rainfall alone to be 325,000. Along with the added burden of climate change and urbanisation, this figure is set to rise to a staggering 555,000 by 2050.
Crucially, the National Infrastructure Commission has identified the need for interdisciplinary collaboration between the government, local authorities, water and sewage companies, internal drainage boards, the Environment Agency, and Ofwat to protect existing homes.
Upgrading the large-scale combined sewers that currently carry away both wastewater and stormwater will be costly, disruptive, and slow, so attention has shifted to installing sustainable drainage systems (SuDS) into developments as the primary way to mitigate flooding. One of the report’s key recommendations is to shift SuDS from exception to expectation in new developments, and the government has since responded with legislation to mandate sustainable drainage in most new developments – anticipated to be implemented this year.
New responsibilities
For housebuilders, the impact of this legislation – Schedule 3 of the 2010 Water Management Act – is to move sustainable drainage from best practice to regulatory responsibility, and shift finding the right solution and products for a project up the list of priorities. The rules will require developers to submit a drainage plan to a local approving authority before a project can be connected to public sewer systems.
This brings housebuilders into that multidisciplinary coalition – along with local authorities, central government and water companies – to relieve the stress on existing drainage infrastructure and reduce the risk of surface water flooding. While the new rules may necessitate a slight learning curve for housebuilders not already fluent in sustainable drainage, they offer opportunities beyond staying compliant.
When done right, SuDS can not only increase flood resilience, but also improve water quality, protect and improve the natural environment, and ultimately add value to projects. Natural aspects of SuDS, such as ponds, swales and tree pits are valuable here, as they closely mirror how the natural environment works to drain and re-incorporate surface water back into the water cycle. Despite the obvious effectiveness of the natural water cycle and these green features, there are some engineered and manufactured elements that are necessary to provide the maximum defences for developments and residents alike. When used in tandem, engineered elements can ensure developments reap the most rewards from those ‘green’ elements used in water management – notably, hitting biodiversity net gain targets set out by recent legislation.
Considering the role of SuDS
As pressures to reach upcoming environmental targets intensify, a range of options are available to housebuilders for them to specify on-site. Sustainability is also a key consideration for product specification, but it’s of the utmost importance that materials that can guarantee durability and longevity are specified for use on-site.
Attenuation tanks can form a key part of sustainable drainage systems (SuDS), which can help housebuilders to provide flood resilience, whilst also ensuring that housing developments remain in-line with sustainability legislation. Attenuation tanks, like Wavin’s AquaCell NG which are made up of 100% recycled and recyclable plastics, help to ensure the robustness and longevity of wider water management systems when installed underground.
SuDS like the Aquacell NG also mirror the natural water cycle by releasing excess rainwater at a more controlled rate, ensuring that waterways avoid becoming overwhelmed and flooded.
A bright future
Sustainable drainage will soon be an essential part of the planning process, but it shouldn’t become another box to tick on the way to securing approval.
Schedule 3, and other sustainability legislation such as Biodiversity Net Gain (BNG), brings with it opportunity more than anything else – the chance to build beautiful, resilient homes that fit perfectly into and support the natural environment. After all, while buyers may not be interested in the ins and outs of the Water Management Act, they’re certainly concerned with the flood resilience, water quality, and proximity to nature of their new home.
With SuDS legislation approaching, it’s developers who can find their feet quickest and find the right products and solutions for their particular projects that will thrive in this new environment.
For more information about SuDS, visit: wavin.com
Martin Lambley is global product manager for urban climate resilience at Wavin