Knight Reservoir | |
---|---|
Location | Surrey |
Coordinates | 51°23′56.6″N0°23′36.2″W / 51.399056°N 0.393389°W |
Type | reservoir |
Basin countries | United Kingdom |
Surface area | 50.5 ha (125 acres) |
Water volume | 5.46 Gl (1.20×10 9 imp gal) |
The Knight Reservoir is a large pumped storage reservoir located in the Borough of Elmbridge in Surrey. It was inaugurated in 1907 and stores up to 2,180 million litres of raw water abstracted from the River Thames prior to its treatment and supply to London and north Surrey. It is located south of the River Thames, west of West Molesey, and between Hurst Road (A3050) and Walton Road (B369). It is adjacent to, and west of, its twin Bessborough Reservoir.
In 1898 the Southwark and Vauxhall Waterworks Company operated a water works at Hampton, Middlesex. To increase the raw water storage capacity the company sought legal powers to construct two reservoirs across the river from the Hampton works. [1] This was achieved through the provisions of the Southwark and Vauxhall Water Act 1898 (61 & 62 Vict. c. cxv) [2] which empowered the company to build two storage reservoirs; an intake from the river Thames; a pump house, and filter beds. [1] Work began in 1898 on the site of an old mansion called Apps Court.
Construction was incomplete when, in 1902, the Metropolitan Water Board (MWB) was formed under the terms of the Metropolitan Water Act 1902 (2 Edw. 7. c.41). The MWB took over the assets of several companies including the Southwark and Vauxhall Waterworks Company and the partly built reservoirs at Walton.
The MWB continued the construction and the reservoirs were inaugurated in 1907. [1]
The Knight and Bessborough reservoirs have a combined area of 125.5 acres (0.508 km2) and hold 1,198 million gallons. [3] Other key details of the reservoirs are as follows. [1]
Parameter | Knight Reservoir | Bessborough Reservoir |
---|---|---|
Capacity | 2,180 Mega litres | 3,260 Ml |
Surface area | 20.8 ha | 30 ha |
Perimeter | 1,800 m | 2,000 m |
Total excavation | 1.15 million cubic metres | |
Puddle clay used | 153,000 cubic metres | |
Concrete | 57,000 cubic metres |
The embankment walls of the reservoirs have a puddle clay core extending down to the underlying blue London clay. [1]
The inlet pipes and water discharge tower are adjacent to the north embankment.
Water from the reservoirs was piped under the river and flowed by gravity to the filter beds at Hampton Water Works. [1]
The Metropolitan Water Board operated the reservoirs until the Board was abolished in 1974 under the provisions of the Water Act 1973 (c. 37). [4] Ownership and control was transferred to the Thames Water Authority (TWA). The water supply industry was privatised in 1989, [5] and the TWA became Thames Water.
Knight and Bessborough Reservoirs are a Site of Special Scientific Interest.
Water was abstracted from the river Thames through an open intake channel (139 m long, 6.7 m wide, with a water depth of 2.4 m) and pumped into the reservoirs. [6] There were four lift pumps which were originally driven by triple-expansion steam engines each rated at 373 kW at 135 rpm. Each engine was coupled to a two-stage centrifugal pump capable of delivering 114 million litres/day. [6] The reservoirs allowed some settlement of suspended solids, biological cleaning through exposure to sunlight, and provided a buffer storage volume to maintain capacity at times of low flow in the river.
The water quality changes which took place during reservoir storage are as follows. [7]
Quarter | Source | Ammoniacal N. | Albumin N. | Nitrate | Phosphate | Turbidity | Agar colony per ml. | E. Coli per 100 ml. |
---|---|---|---|---|---|---|---|---|
March to May | River Thames before storage | 0.25 | 0.23 | 4.7 | 1.8 | 18 | 5387 | 5298 |
Walton reservoir outlet | 0.26 | 0.16 | 4.8 | 1.6 | 5 | 236 | 55 | |
June to August | River Thames before storage | 0.12 | 0.25 | 3.9 | 2.3 | 19 | 1880 | 2576 |
Walton reservoir outlet | 0.21 | 0.17 | 3.8 | 2.1 | 3 | 68 | 7 | |
Sept. to Nov. | River Thames before storage | 0.27 | 0.24 | 4.0 | 2.4 | 17 | 6520 | 4850 |
Walton reservoir outlet | 0.24 | 0.17 | 3.8 | 2.3 | 3 | 226 | 87 | |
Dec. to February | River Thames before storage | 0.31 | 0.26 | 4.6 | 2.1 | 31 | 9737 | 5288 |
Walton reservoir outlet | 0.23 | 0.14 | 4.6 | 1.8 | 4 | 324 | 108 |
As originally conceived water from the reservoirs was piped under the river and flowed by gravity to the filter beds at Hampton Water Works. The difference in level between the reservoirs and the filter beds was 9.7 m. The flow of water drove three hydraulic turbines coupled to centrifugal pumps which were used to lift river water into the reservoirs. [1] In addition to the Knight and Bessborough reservoirs there were four smaller rectangular reservoirs (each 750 ft by 550 ft, 229 m by 167 m) located east of the intake channel. [8]
In the 1920s a water treatment works was constructed to the north of the reservoirs. By 1933 this comprised six slow sand filters (each 220 ft by 170 ft, 67 m by 52 m) located west of the intake channel. [9]
In 1926 the steam engines were converted to single cylinder triple expansion steam pumps and steam turbines. [6] Further filter beds were added in 1950 west of the pump house.
Further plant was added as the demand for water grew, and when the Queen Elizabeth II reservoir was commissioned in 1962. The steam engines were replaced with electric motors in 1964. [6]
Elmbridge is a local government district with borough status in Surrey, England. Its council is based in Esher, and other notable towns and villages include Cobham, Walton-on-Thames, Weybridge and Molesey. The borough lies just outside the administrative boundary of Greater London, but is mostly within the M25 motorway which encircles London. Many of the borough's urban areas form part of the wider Greater London Built-up Area.
Seething Wells is a neighbourhood in southwest London on the border between Surbiton in the Royal Borough of Kingston upon Thames in Greater London, and Elmbridge in Surrey. The area was historically a waterworks that supplied London with water from the River Thames. Nowadays it is mainly a residential area, with the notable exception of decommissioned filter beds — the Seething Wells Filter Beds — in the northwest part of the area that borders the Thames.
Molesey is a suburban district comprising two villages, East Molesey and West Molesey, in the Borough of Elmbridge, Surrey, England, and is situated on the south bank of the River Thames.
The Metropolitan Water Board was a municipal body formed in 1903 to manage the water supply in London, UK. The members of the board were nominated by the local authorities within its area of supply. In 1904 it took over the water supply functions from the eight private water companies which had previously supplied water to residents of London. The board oversaw a significant expansion of London's water supply infrastructure, building several new reservoirs and water treatment works.
Molesey Lock is a lock on the River Thames in England at East Molesey, Surrey on the right bank.
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The Molesey Reservoirs were a group of reservoirs in England near Molesey, Surrey, in the western suburbs of London. There was an adjacent water treatment works.
The Stain Hill Reservoirs in London, England with embankments occupy 0.175 square kilometres. They are a pair which sit high between others; Kempton Nature Reserve; riverside houses in Sunbury-on-Thames; and a low area of flood meadow to the west alongside the closing stretch of the Port Lane Brook. Other nearby settlements are Molesey, Hampton and Hanworth.
The Bessborough Reservoir is an embanked storage reservoir south of the River Thames in Surrey adjacent to the Knight Reservoir. To the south lies Queen Elizabeth II Reservoir and to the north the now disused Molesey Reservoirs. The A3050 runs to the north of the reservoir and the neighbouring town is Molesey to the east. It forms part the green buffer between Molesey and Walton on Thames. The reservoir is in the borough of Elmbridge.
The Island Barn Reservoir lies south of the River Thames in England at West Molesey and north of Lower Green, Esher. The reservoir has a surface area of 122 acres (0.49 km2) and a capacity of 922 million gallons. Managed by Thames Water, it is in the Borough of Elmbridge and is surrounded by the River Mole to the west and the River Ember to the east. Queen Elizabeth II Reservoir is a larger reservoir to the West.
The Queen Elizabeth II Reservoir lies to the south of the River Thames and to the west of the Island Barn Reservoir. To the north are the Bessborough and Knight reservoirs. The A3050 runs to the north of the reservoir and it is situated in Walton on Thames. It is managed by Thames Water.
Sunnyside Reservoir is a reservoir forming part of the Hampton waterworks complex within the London borough of Richmond-upon-Thames.
London's water supply infrastructure has developed over the centuries in line with the expansion of London.
Grand Junction Isle is a small island in the River Thames on the reach above Molesey Lock at Sunbury-on-Thames, Surrey, England. It is just downstream of Sunbury Court Island, which is three times longer and also close to the north bank.
The Southwark and Vauxhall Waterworks Company was a utility company supplying water to parts of south London in England. The company was formed by the merger of the Southwark and Vauxhall water companies in 1845 and became part of the publicly owned Metropolitan Water Board in 1904.
The Lambeth Waterworks Company was a utility company supplying water to parts of south London in England. The company was established in 1785 with works in north Lambeth and became part of the publicly owned Metropolitan Water Board in 1904.
The West Middlesex Waterworks Company was a utility company supplying water to parts of west London in England. The company was established in 1806 with works at Hammersmith and became part of the publicly owned Metropolitan Water Board in 1904.
The Walton water treatment works are an advanced purification works supplied with raw water and producing and delivering potable water to the locality and into the Thames Water ring main. The Walton water treatment works were initially built in 1907 north of the Bessborough and Knight reservoirs which supply the water works.
The Kempton Park water treatment works, in the London Borough of Hounslow and Kempton Park Surrey, takes raw settled water abstracted from the River Thames and supplies treated potable water to consumers in north and west London. The works were inaugurated in 1906 and continue to provide treated water.
Hampton Water Treatment Works are water treatment works located on the River Thames in Hampton, London. Built in the second half of the 19th Century to supply London with fresh water, the Waterworks was in the past a significant local employer, and its brick pumphouses dominate the local landscape. The Waterworks are currently owned and operated by Thames Water, occupying a 66 ha site located between the Upper Sunbury Road (A308) and the River Thames. The Waterworks currently has a maximum output of 700 megalitres a day, and supplies ~30% of London's fresh water.