With the second highest rainfall on record in a year which started with drought, 2012 has certainly bought a lot of comment about changing weather patterns and the challenges we face in dealing with the increase in flooding we have been experiencing. The BBC recently reported on how the ground is completely saturated with water and has nowhere else to go underground. The feature also comments on how the groundwater levels have risen faster than any other time since records began in the 1830s, leaving us in unknown territory as to how the groundwater will respond.
Forecasting our weather has always been a topic of much discussion and it has been particularly difficult to predict over the past few months. Milder air holds more moisture and has the propensity to produce much more intense rainfall. When the ground is already full, however, water simply runs along the surface – causing the excessive flooding we have been seeing. The big concern is that these sorts of conditions become the norm and we see these events occurring more frequently year on year. So what can we do for the future?
The requirement for sustainable drainage schemes (SuDS) provision in Schedule 3 of the Flood and Water Management Act 2010 is scheduled to be enforced in 2014. Where we have continued to urbanise our landscape, issues arise with fast water runoff through conventional piped drainage which overwhelms the sewer capacity – a situation we have seen all too much of during the past 12 months. SuDS require that drainage mimics runoff from the site in its natural state using techniques such as retention and infiltration along with linear channel drainage to provide an effective conveyance mechanism to transfer surface water. The aim is to reduce the rate of rainwater runoff and therefore reduce the risk of flooding.
A SuD needs to be an adaptable and flexible solution to suit individual site requirements. Combining ‘hard’ (or engineered) and ‘soft’ (or natural) components to best effect will certainly help to counter the effects of urbanisation. However in an environment where any system is struggling to cope with volume, will the forthcoming legislation really be effective in delivering all it seeks to? Can it really deliver Quantity management, Quality Management and Quality amenity?