[1] Excavation work on the reservoir started in 1936 under the supervision of the Board's chief engineer Jonathan Davidson but was suspended upon the outbreak of war in 1939.

[5] On both sides of the core is a fill of mixed clay and gravel 0.9 metres (2 ft 11 in) wide.

A study in 2009 identified that about 750,000 tonnes of sand and gravel could be excavated from the bottom of the reservoir.

The inlet and outlet tunnels are 2.5 metres (8.2 ft) in diameter and run beneath the Knight and Bessborough reservoirs, nearby roads and houses to the Walton Water Treatment Works.

[9] The reservoir covers 128 ha (317 acres), has a mean depth of 15.3 metres (50 ft), a maximum depth of 17.8 metres (58 ft) and holds 4,300 million gallons (20,000 million litres).

[11] Little auks, red-necked phalarope, Bonaparte's gulls, roseate terns, pomarine skuas and shore larks have also been spotted at this reservoir.

[12] As of 2020 Thames Water are reviewing the access arrangements for all three of the Walton reservoirs,[13] The design of the reservoir has an effect on the fish population that can live in the reservoir, the concrete shores means that only European perch and ruffe can breed, except for where there are empty fish cages constructed with netting, which support some plant growth and this allows small numbers of cyprinid fish to breed.