Surface water flooding
The inability of our existing drainage systems to cope with changing weather conditions was brought sharply into focus by the unprecedented floods experienced across Great Britain in 2007 and highlighted again, more recently, by serious flooding in the winter of 2013/14.
The Environment Agency estimated that
over two thirds of the 57,000 homes affected by the 2007 floods were not flooded by swollen rivers, but by water running off paving or overflowing from the overloaded drainage systems serving them.
The reason for this is simple. The majority of our existing drainage systems are designed to remove rainwater as quickly as possible from where it falls and direct it into watercourses or drains. This means in cases of prolonged, heavy rainfall the public sewer system quickly reaches its capacity and consequently overflows.