For history, 2012 will not be an insignificant year, the Queen’s Diamond Jubilee and the London Olympics have assured this. In metrological terms it also looks set to be red lettered in the record books: April 2012 was the wettest April since British rainfall records began. The month saw an average of 4.8in (121.8mm) of rainfall; almost double the established average levels for April of 2.7in (69.6mm), and resulted in substantial flooding across parts of the UK.
An image of extremes
Swanage in April
Ironically, April’s prolific rainfall followed a sustained period of drought: 20 of the previous 25 months recorded below average levels of rainfall across the UK. March 2012 was the fifth driest March on record, with just 36.4mm of rainfall in comparison to an average of 95.9mm.
But then a wet, wet April was followed by the warmest May on record in the northern hemisphere, with an average land and ocean surface temperature of 0.85°C (1.53°F), up to 5°C (9°F) above the expected, average seasonal temperature. The UK reaped the leisurely benefits of this spike with a heat wave in the second half of the month. Therefore, on reflection, the broader weather picture appears to depict a landscape whose infrastructures – including water supply and drainage – are potentially facing a range and level of systems challenges unseen in the modern age.
Changing weather patterns
April 24th 2012
British weather patterns, in terms of drought and rainfall cycles, have become increasingly irregular in recent years. While drought is a cyclical feature of UK weather, with an average of two years in each decade suffering substantially, the years since 2007 have had summers (the typical drought season) marked by unseasonably heavy sustained rainfall and instances of significant flooding.
While weather patterns have incrementally changed in recent years, flash flooding has become an increasingly familiar occurrence. June 2007 broke records for summer rainfall and resulted in havoc-reeking flooding. April 2012’s tumultuous rainfall saw South Wales and southwestern England hardest hit – with many of the flood victims of 2007 again affected.
In Hampshire on April 30th, a man was drowned when attempting to cross a flooded road; while on the same day 1000 people were evacuated from a flooded, nearby Caravan Park – this area was also affected by flooding in 2007.
Likewise, the town of Tewkesbury in Gloucestershire, which has a history of flooding and was devastated during the 2007 floods, again found its streets under more than a foot of muddy floodwater this April.
The lessons of April
The floods of 2007, which saw damages of £6 billion sustained across parts of Britain, led to the Pitt report (2008) and the Flood and Water Management Act for England and Wales (2010). Further legislation to govern and promote the advancement of SUDS in the UK is under development.
These legislative developments have raised hopes for the emergence of a truly sustainable approach to how surface rainwater is managed in the UK. April’s floods, in reinforcing the lessons of 2007, surely point to where we should begin: targeting redevelopment of infrastructures in areas vulnerable to flooding, with bespoke sustainable drainage systems.
The residents of town’s such as Tewkesbury, who know only too well that to ignore history is the most certain route to repeating it, would surely agree that the challenges presented by changing weather patterns call for the systematic introduction of a sustainable approach to storm water management and flood control.