The William Girling Reservoir is located in the

London Borough of Enfield The London Borough of Enfield () is a London boroughs, London borough in North London. It borders the London boroughs of London Borough of Barnet, Barnet to the west, London Borough of Haringey, Haringey to the south, and London Borough of Walt ...

and is part of the

Lee Valley Reservoir Chain The Lee Valley Reservoir Chain is located in the Lee Valley, and comprises 13 reservoirs that supply drinking water to London. The Reservoir Chain is a major geographic constraint; together with the Thames it is one of the two significant topogr ...

that supplies London with drinking water. It is named after William Girling OBE, a chairman of the

Metropolitan Water Board 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 functi ...

(MWB). The reservoir and the nearby

King George V Reservoir The King George V Reservoir, also known as King George's Reservoir, is located in the London Borough of Enfield and is part of the Lee Valley Reservoir Chain that supplies London with drinking water. The storage reservoir is bordered by Sewardstone ...

are known collectively as the Chingford Reservoirs. The storage reservoir, which is owned by

Thames Water Thames Water Utilities Ltd, known as Thames Water, is a large private utility company responsible for the public water supply and waste water treatment in most of Greater London, Luton, the Thames Valley, Surrey, Gloucestershire, north Wiltshir ...

, is bordered by

Chingford Chingford is a town in east London, England, within the London Borough of Waltham Forest. The town is approximately north-east of Charing Cross, with Waltham Abbey to the north, Woodford Green and Buckhurst Hill to the east, Walthamstow to the ...

to the east and

Ponders End Ponders End is the southeasternmost part of Enfield, north London, centred on the Hertford Road. Situated to the west of the River Lee Navigation, it became industrialised through the 19th century, similar to the Lea Valley in neighbouring Edm ...

and

Edmonton Edmonton ( ) is the capital city of the Canadian province of Alberta. Edmonton is situated on the North Saskatchewan River and is the centre of the Edmonton Metropolitan Region, which is surrounded by Alberta's central region. The city ancho ...

to the west, and covers with a perimeter of . There is no public access.

History

The reservoir was conceived as part of an overall plan for the

Lea Valley The Lea Valley, the valley of the River Lea, has been used as a transport corridor, a source of sand and gravel, an industrial area, a water supply for London, and a recreational area. The London 2012 Summer Olympics were based in Stratford, in ...

and laid before the Royal Commission on Water Supply (Balfour Committee) in 1893. At the time the responsible authority was the

East London Waterworks Company The East London Waterworks Company was one of eight private water companies in London absorbed by the Metropolitan Water Board in 1904. The company was founded by Act of Parliament in 1806, and in 1845 the limits of supply were described as ''" ...

. However, under the provisions of the

Metropolis Water Act 1902 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 functi ...

, the undertakings of this and seven other companies were transferred to the Metropolitan Water Board (MWB). Work began in 1936 when the tender of

John Mowlem John Mowlem (12 October 1788 – 8 March 1868) was an England, English stonemason, builder and founder of the quarrying and construction company "Mowlem, Burt and Freeman". Career Mowlem was born in Swanage, Dorset, the son of a quarryman. As a ...

(for £682,156) was accepted. The project was led by

civil engineer A civil engineer is a person who practices civil engineering – the application of planning, designing, constructing, maintaining, and operating infrastructure while protecting the public and environmental health, as well as improving existing ...

, Robert Wynne-Edwards. Due to the use of mechanical scrapers and

bulldozers A bulldozer or dozer (also called a crawler) is a large, motorized machine equipped with a metal blade to the front for pushing material: soil, sand, snow, rubble, or rock during construction work. It travels most commonly on continuous track ...

, which were being used for the first time in British dam construction, progress was rapid. The design, by Sir Jonathan Roberts Davidson, President of the Institution of Civil Engineers 1948/49, attracted widespread technical interest in 1937 when a major slip occurred in the partly formed embankment at the north-west corner. When the embankment fill had reached a width had dropped and moved forward . Fortunately, the dam failed before any water had been stored. Investigations were under way when a second slip occurred in December 1937. Two independent

soil mechanics Soil mechanics is a branch of soil physics and applied mechanics that describes the behavior of soils. It differs from fluid mechanics and solid mechanics in the sense that soils consist of a heterogeneous mixture of fluids (usually air and wat ...

experts, Dr. Herbert Chatley and Professor

Karl Terzaghi Karl von Terzaghi (October 2, 1883 – October 25, 1963) was an Austrians, Austrian Mechanical Engineer, mechanical engineer, geotechnical engineer, and geologist known as the "father of soil mechanics and geotechnical engineering". Early life I ...

, were called in and both made recommendations. In July 1938 the MWB made important modifications to the original design. Subsequent investigations into this landslip can be regarded as the birth of modern soil mechanics in

Britain Britain most often refers to: * The United Kingdom, a sovereign state in Europe comprising the island of Great Britain, the north-eastern part of the island of Ireland and many smaller islands * Great Britain, the largest island in the United King ...

. The reservoir was redesigned to increase its capacity by 11.3%. Construction was further delayed by the outbreak of the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...

and the reservoir was not finally completed until 1951, when it was officially opened on 4 September by William Girling,

Chairman The chairperson, also chairman, chairwoman or chair, is the presiding officer of an organized group such as a board, committee, or deliberative assembly. The person holding the office, who is typically elected or appointed by members of the grou ...

of the MWB, and named eponymously. As part of the

2012 Summer Olympics The 2012 Summer Olympics (officially the Games of the XXX Olympiad and also known as London 2012) was an international multi-sport event held from 27 July to 12 August 2012 in London, England, United Kingdom. The first event, the ...

security exercise, the reservoir was identified as suitable for the deployment of

Rapier A rapier () or is a type of sword with a slender and sharply-pointed two-edged blade that was popular in Western Europe, both for civilian use (dueling and self-defense) and as a military side arm, throughout the 16th and 17th centuries. Impor ...

surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...

Description

The

geology Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ear ...

of the site is

alluvium Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. Alluv ...

underlain by river terrace gravels and in turn overlying the

London Clay The London Clay Formation is a marine geological formation of Ypresian (early Eocene Epoch, c. 56–49 million years ago) age which crops out in the southeast of England. The London Clay is well known for its fossil content. The fossils from t ...

formation. The reservoir is formed by a continuous earthen embankment that encloses the basin. The embankments consist of a central puddle clay core with a selected material adjacent to the core forming a filter. The core is a maximum of wide at the base and tapers to wide at the crest. The core typically extends into the London Clay to form a watertight cut off. The embankment shoulders consist of zones of

ballast Ballast is material that is used to provide stability to a vehicle or structure. Ballast, other than cargo, may be placed in a vehicle, often a ship or the gondola of a balloon or airship, to provide stability. A compartment within a boat, ship, ...

and filling material. The upper embankments slopes are 1 in 2.5 externally, whilst the lower slopes to the

berm A berm is a level space, shelf, or raised barrier (usually made of compacted soil) separating areas in a vertical way, especially partway up a long slope. It can serve as a terrace road, track, path, a fortification line, a border/ separation ...

were constructed at a bank slope of 1 in 8. It was considered necessary to reinforce the NW corner (Ponders End) with sheet-piling which was driven, suspended from a Weldex crane (see photo) ending in 2020

Inflow

Water is pumped from the

River Lee Diversion The River Lee Diversion is located in the Lea Valley, close to Enfield Lock and to the north east corner of the King George V Reservoir. History As its name implies, the River Lea was diverted to accommodate the construction of the Chingford ...

through five inlet pumps with a maximum of 600 ML/d, though normal operation is 250 ML/d. In addition there are two 200 mm diameter inlets from the North London Artificial Recharge borehole scheme.

Outflow

The outlet tower consists of a

granite Granite () is a coarse-grained (phaneritic) intrusive igneous rock composed mostly of quartz, alkali feldspar, and plagioclase. It forms from magma with a high content of silica and alkali metal oxides that slowly cools and solidifies undergro ...

faced dry shaft that houses a diameter vertical pipe, with draw-off pipes at four different levels. The lower end of the standpipe is connected to a diameter steel outlet

conduit Conduit may refer to: Engineering systems * Conduit (fluid conveyance), a pipe suitable for carrying either open-channel or pressurized liquids * Electrical conduit, a protective cover, tube or piping system for electric cables * Conduit curre ...

. The water is conveyed to the

Coppermills Water Treatment Works The Coppermills Water Treatment Works is a large water treatment works in the Lea Valley in east London. Completed in 1969 by the Metropolitan Water Board, it is now owned and operated by Thames Water. In 2009, Coppermills was connected to the Tha ...

for treatment, with the facility for bulk transfer to

Essex and Suffolk Water Essex and Suffolk Water is a water supply company in the United Kingdom. It operates in two geographically distinct areas, one serving parts of Norfolk and Suffolk, and the other serving parts of Essex and Greater London. The total population ser ...

Ecology

The water is part of the Chingford Reservoirs

Site of Special Scientific Interest A Site of Special Scientific Interest (SSSI) in Great Britain or an Area of Special Scientific Interest (ASSI) in the Isle of Man and Northern Ireland is a conservation designation denoting a protected area in the United Kingdom and Isle of ...

(SSSI).English Nature citation, Chingford Reservoirs
Retrieved 21 December 2007 It is a major wintering ground for

wildfowl The Anatidae are the biological family of water birds that includes ducks, geese, and swans. The family has a cosmopolitan distribution, occurring on all the world's continents except Antarctica. These birds are adapted for swimming, floating on ...

and

wetland A wetland is a distinct ecosystem that is flooded or saturated by water, either permanently (for years or decades) or seasonally (for weeks or months). Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The ...

birds, including nationally important numbers of some species. The water also forms a moult refuge for a large population of wildfowl during the late summer months. A total of 85 wetland species have been recorded here in recent years.

Gallery

File:Weldex 24 9 20.jpg, Weldex crane below embankment. File:Crane Girling Reservoir 1 k.jpg, Weldex carrying out

sheet piling Sheet or Sheets may refer to: * Bed sheet, a rectangular piece of cloth used as bedding * Sheet of paper, a flat, very thin piece of paper * Sheet metal, a flat thin piece of metal * Sheet (sailing), a line, cable or chain used to control the cle ...

work NW corner of reservoir. File:William Girling Reservoir, K.jpg, View west towards Ponders End

References

External links

Reservoir Information

English Nature, Chingford Reservoirs citation

English Nature, Nature on the Map, Chingford Reservoirs

News report on the opening of the reservoir at BBC Archive
{{authority control Sites of Special Scientific Interest in London Thames Water reservoirs Reservoirs in London Drinking water reservoirs in England