Can storm water management and planning be the answer to preventing flooding in the UK?

Jeremy Jones | 05 Dec 2016 | Comments

With the disruption that storm Angus left behind last week, it provokes the question – are we doing enough to prevent flooding and tackling it at source? Last week during the height of the storm, we had 103 flood alerts in place; a high of 2 inches of rain in Exeter; and flooded properties and roads in Devon.

Our weather conditions are showing no signs of changing. Rainfall has increased across all regions of the UK over the last 50 years – winters are wetter and even with drier summers, rainfall is becoming concentrated into more intensive downpours (up 5% in the last 20 years).

Traditional methods of removing rainwater – i.e. removing it as quickly as possible from our roads and pavements through the network and out to sea – are not always fit for purpose during periods of severe rainfall. Climate change, urban creep and new developments have together meant that the infrastructure is no longer adequate. So after each period of heavy rain as technical experts we continue to bang the drum that more preventative action should be taken instead of last minute urgent care. 

Attention then has to turn to Storm Water Management (SWM) and sustainable urban drainage systems (SuDS). SuDS mimic natural processes enabling natural drainage around buildings and other developments which work by slowly draining, or sometimes holding in surplus water caused by rain and surface water. We are now seeing SuDS not only employed in new developments but also as a retrofit opportunity for water companies, with many water companies now grasping the opportunity and developing processes, governance procedures and implementing new measures for SWM.

At Atkins we are advisors to the majority of UK water companies. In addition to assisting them with new ways of working for SWM, we have created the SuDS Studio toolkit which is a unique geospatial tool that brings together our experience in planning and engineering with cutting edge geospatial modelling capabilities. It works by rapidly mapping out potential areas which could benefit from the implementation of SuDS. As a rapid scanning tool, it is a much more cost effective tool than the traditional approach of assessing each area individually. It also prioritises the opportunities for SuDS, which is extremely helpful to the end user. 

As experts working with SuDS on a daily basis, we continue to praise the benefits. SuDS can typically cost less than half of what traditional drainage systems cost, and they can cost much less than retrospective flood defences (even though these will remain an essential part of the flooding protection mix). They also have a range of benefits – not only do they remove large amounts of surface water from entering into the sewer network and watercourses (preventing overloading, and reducing flooding), they also encourage ground water recharge; reduce pollutant concentration; and provide habitats for wildlife. And they also can really improve the aesthetics of an area – the introduction of plants, wild flowers and trees can do much to improve heavily urbanised areas.

Whilst it is reassuring that a number of water companies are beginning to realise the benefits of SWM and SuDS, we are a long way from it being recognised as a mainstream approach to reduce the risk of flooding. The positivity around the 2010 Floods and Water Management Act (FWMA) which sought to enshrine SuDS has now levelled off – 6 years on and there is still no official approval body that has complete oversight of SuDS schemes. Schedule 3 (SuDS Standards) fell between a change of government and despite originally having cross party support, was not commenced. The reasons for this are varied and can be debated at length, but fundamentally the fact remains that the SuDS Approving Bodies (SABs) were never properly implemented as Schedule 3 recommended and that gap remains today. That said, whilst we may have another battering of flooding this year, and subsequently resort to our traditional methods of dealing with the damages, I am hopeful of an uptake of more SuDS schemes. Some water companies are getting behind the SuDS agenda and that’s a good start at least.  We’re also seeing a raft of changes in local authorities. Planners are coming on board and there is a greater desire to collaborate with others. This, I hope, will lead to integrated social solutions that generations to come will be proud of.