Grafham Water is an 806.3-hectare biological Site of Special Scientific Interest southwest of Huntingdon in Cambridgeshire. It was designated an SSSI in 1986. It is a reservoir with a circumference of about 16 km, is 21 m deep at maximum, and is the eighth largest reservoir in England by volume and the third largest by area at 6.27 km2. An area of 114 ha at the western end is a nature reserve managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire.The lake was created by building an earth and concrete dam, constructed by W. & C. French in 1965, and water is extracted and processed at an adjacent Anglian Water treatment plant before being piped away as drinking water.
The reservoir was immediately colonised by wildlife and a nature reserve was created at the western side of the reservoir. The nature reserve contains semi-natural ancient woodlands and more recent plantation woodlands, grasslands and wetland habitats such as reedbeds, willow and open water.
Address PE28 0, United Kingdom
Coordinates 52°17'53.793" N -0°18'51.289" E