More than a storm in a teacup
One of the most important environmental challenges facing the UK is how to deal with extreme weather conditions, particularly stormwater innundations. Terry Sloman, regional sales support manager, Burdens Utilities, discusses stormwater management and how to future-proof properties and developments
The subject of stormwater management is fast becoming one of the UK’s primary concerns in the area of environmental issues we need to be prepared for. According to Defra, more than 5M properties in the UK are at risk of flooding, which equates to one in every six homes in the UK.
Meanwhile, the UK government has recently published its National Adaptation Programme, detailing plans to enhance the UK’s resilience to a changing climate and increasing weather extremes. Yet, while the government has announced that it is taking measures to better protect more than 64,000 more homes through 93 new flood defences, the £294M scheme has been criticised for favouring the ‘big cities’ rather than rural areas that were significantly hit by high levels of flooding in winter 2012.
It is becoming ever more apparent how important it is to anticipate and manage severe flooding situations. Since rain records began in 1766, the amount of rainfall has continued to increase in the UK.
In 2000, UK flooding was at its worst for 270 years in many areas, and in 2009 some areas such as Cumbria witnessed widespread flooding. The Environment Agency estimates that the average annual cost of flood damage in England is more than £1Bn.
High volumes of stormwater run-off place increased stress on existing drainage systems and urban watercourses. When a previously undeveloped site is built on and paved over, stormwater run-off from the newly impermeable surface increases by up to 80%, which places greater pressure on existing watercourses and drainage infrastructure.
This can lead to downstream flooding, localised erosion, the destruction of habitats and combined sewer overflows. The traditional means of dealing with increased stormwater is just not viable anymore.
This problem is not only limited to the UK. Australia is pressing ahead with its Water Sensitive Urban Design initiative, following a series of floods and some of the worst droughts recorded in history. These affect the health, well-being, safety and productivity of the population, and the result is an awareness about the impact of stormwater that is now considered in all development planning and policy responses to climate change.
Joining up the water cycle and making better use of rainwater will help significantly reduce the risk of water stress on developments and the health and safety of the general public. The UK is catching up to this way of thinking.
A recent report by the Construction Industry Research & Information Association (CIRIA) in March states: “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 nuisance rather than an asset or opportunity.”
As we move forward, we need to acknowledge the challenges that stormwater presents, but then consider how we can future-proof new and existing developments to cope with these growing pressures, and harness water as an opportunity.
Flooding has a dramatic impact on people’s lives. Ever since the Pitt Review in 2007, the importance of considering surface water risk has become enshrined in a development’s planning stages.
The report identified some of the key issues that needed to be addressed and the lessons learned following the floods in the summer of 2007. These include maintaining power and water supplies, protecting essential services, providing better advice and help to those affected by flooding, and ensuring the highest standard of resource and care is delivered.
However, to improve our ability to withstand the levels of flooding witnessed in recent years, section three of the Pitt Review, entitled ‘Reducing the risk of flooding and its impact’, should still be the top priority.
The latest Sustainable Urban Drainage Systems (SUDS) have been developed to cope with the demands that heavy rainfall can place on an area. Indeed, integrated systems incorporating attenuation tanks, large capacity drainage channels, lagoons or ponds, porous paving and rainwater harvesting are now an essential part of any new development. Fully-integrated SUDS is a combination of several product systems that form an end-to-end solution that guarantees performance, while offering the customer optimum value. The solutions available include stormwater infiltration modular cells, large diameter pipework, separation tanks and flow control regulators.
In order to achieve smarter stormwater management, a collaborative relationship between all stakeholders is required. Urban regeneration will improve public open spaces and surrounding buildings, plus there is the possibility of using surface water to create features that form part of the urban realm. This will lead to long-term benefits: enhanced public spaces, greater biodiversity and increased land value.
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