Wraysbury Reservoir is a water supply reservoir for London, just west of the M25 near the village of Wraysbury, and directly under the western approach path of Heathrow Airport. Construction of the reservoir was begun in 1967 and completed by W. & C. French in 1970 with a capacity of 34,000 million litres (8,000 million gallons).
Engineering design data for the Wraysbury reservoir is as follows.
Spelthorne is a local government district with borough status in Surrey, England. Its council is based in Staines-upon-Thames; other settlements in the area include Ashford, Sunbury-on-Thames, Shepperton, Stanwell and Laleham. It is named after the medieval Spelthorne Hundred which had covered the area.
The borough is largely urban; although outside the boundaries of Greater London, it is almost entirely inside the M25 motorway which encircles London. The borough contains several large reservoirs, including the Wraysbury Reservoir, Staines Reservoirs and Queen Mary Reservoir, which all supply fresh water to London and surrounding areas.