Staines Reservoirs

From the Wikipedia page

The Staines Reservoirs lie to the east of the King George VI Reservoir near Heathrow airport in the county of Surrey within the Colne Valley regional park. The village of Stanwell is nearby as is the town of Staines. The two reservoirs are placed between the A3044 and the A30. They were built in 1901.

The area has been designated a Site of Special Scientific Interest (SSSI) as it carries important wintering populations of tufted ducks, pochard, goosander and goldeneye.