Increased rainfall has caused devastating flooding across the UK in recent years, with climate change and growing urbanisation attributed as two key causes. According to DEFRA, more than five million properties in the UK are at risk of flooding, which equates to one in six homes in the UK.
The latest Sustainable Urban Drainage Systems (SUDS) have been developed to cope with the demands that heavy rainfall can place on an area, but what are the key innovations that local authorities and builders need to be aware of when selecting the best system to meet these requirements?
High volumes of storm-water run-off puts a strain on existing drainage systems and urban watercourses. When a previously undeveloped site is built on and paved over, storm-water run-off from the newly impermeable surface increases by up to 80 percent, which puts even greater pressure on existing watercourses and drainage infrastructure. This can lead to downstream flooding, localised erosion and is a contributing factor of combined sewer overflows.
The need for alternative drainage solutions is rapidly growing to meet increasing environmental challenges. A new report from the Construction Industry Research and Information Association (CIRIA), titled ‘Water Sensitive Urban Design in the UK’, continues this line of thought. In its opening paragraph, it states:
‘The relationship between the places we live and the water resources we depend on is often not prioritised in the design and evolution of those places. Water shortages, flooding and watercourse pollution are all signs of stress where developed areas have a troubled interaction with the natural water cycle and where, conversely, water has become a risk or a nuisance rather than an asset or opportunity.’
As an industry renowned for our innovation, we need to respond to this challenge. Initiatives such as Planning Policy Statement 25 have been established to set out government policy on development and flood risk, ensuring it is taken into account at all stages of the planning process. Nevertheless, there is undoubtedly a need to constantly monitor and report on best practice in the field of SUDS, reviewing processes to ensure the most effective system has been installed.
In line with SUDS policy, Drain Center recommends restricting storm-water run-off through two measures. First, by temporary storage of excess flows so that immediate outflow into streams and rivers is limited. Secondly, by efficient soakaways to infiltrate storm water into the ground.
These measures have led to a sharp increase in the use of storm-water infiltration cells to create underground structures for infiltration or temporary storage of storm water. The benefits of these systems are numerous, including significantly reduced flooding risk while providing a controlled means of releasing storm water into existing sewer systems or watercourses, delivering a sustainable and cost-effective environmental solution. It’s something to think about.
Terry Sloman is the southern sales office manager at Drain Center.