Grafham Water Claimed

Grafham Water is an 806.3 hectare biological Site of Special Scientific Interest (SSSI) south-west of Huntingdon. It was designated an SSSI in 1986. It is a reservoir with a circumference of about 10 miles (16 km), and is the eighth largest reservoir in England by volume and the third largest by area at 1,550 acres (6.28 km²). An area of 114 hectares at the western end is a nature reserve managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire

The lake was created by filling a valley full of water which is retained by an earth and concrete dam in 1965 and is extracted and processed at an adjacent Anglian Water treatment plant before being piped away as drinking water. The water level can be controlled constantly via the pumps which pump water from the River Great Ouse nearby. There are two pumping stations associated with the reservoir. One is located just behind the dam, the other at Offord Cluny alongside the River Great Ouse. At times of high potential flood risk, Grafham Water treatment works can increase the amount of water it takes up to maximum capacity to help reduce the risk of flooding along the river. The reservoir was immediately colonised