River Severn 2007

The River Severn is 220 miles (354km) long, the longest river in Great Britain. It rises at an altitude of 2,001 feet (610 m) on Plynlimon near Llanidloes, Powys, in the Cambrian Mountains of mid Wales. It then flows through Shropshire, Worcestershire and Gloucestershire, with the county towns of Shrewsbury, Worcester, and Gloucester on its banks.
With a large discharge in Gloucestershire, the Severn is England's greatest river in terms of water flow, and is considered one of the ten major rivers of the United Kingdom.
The Severn's drainage basin area is 11,420 square kilometres (4,409 sq miles). The major tributaries to the Severn are the Vyrnwy, Teme, Warwickshire Avon and Stour.


Why did the river flood in 2007?
June was one of the wettest months on record in Britain . Average rainfall across England was 140 millimetres, more than double the June average. Some areas received a month's worth of precipitation in just 24 hours. All this meant that the ground was already saturated by July which had unusually unsettled weather and above-average rainfall through the month, peaking on 20 July when more than 120 mm of rainfall fell in southern Britain . The infiltration capacity of the soil was at a minimum and overland flow occurred very rapidly. The river reached its bankfull levels very quickly and so the floodplain was flooded with water.

The flooding was made worse because towns such as Tewksbury and Gloucester are built on the floodplain of the river. This is the naturally low lying land adjacent to the river channel which is easiest to build on. Urban environments are made up of hard concrete surfaces which do not allow water to infiltrate naturally into the soil. Sewers and drainage systems also allow the water to flow to the river much faster than in a natural environment. However there was criticism that some sewers and drains were blocked and this meant that water built up and contributed to the severity of the flooding.