William Girling Reservoir
Encyclopedia
The William Girling Reservoir is located in the London Borough of Enfield
and is part of the Lee Valley Reservoir Chain
that supplies London with drinking water. It is named after William Girling OBE, a chairman of the Metropolitan Water Board (MWB). The reservoir and the nearby King George V Reservoir
are known collectively as the Chingford Reservoirs
. The storage reservoir, which is owned by Thames Water
, is bordered by Chingford
to the east and Ponders End
and Edmonton
to the west, and covers 334 acres (135 hectares) with a perimeter of 3.5 miles (5.6 km). There is no public access.
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
. However, under the Provisions of the Metropolis Water Act of 1902, 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
(for £682,156) was accepted. The project was led by civil engineer
, Robert Wynne-Edwards
. Due to the use of mechanical scrapers and bulldozers, 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 23 feet (7 m) a 66 foot (20 m) width had dropped 2 feet 4 inches (70 cm) and moved forward 13 feet (4 m). 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
experts, Dr. Herbert Chatley and Professor Karl Terzaghi, 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
. The reservoir was redesigned to increase its capacity by 11.3%.
Construction was further delayed by the outbreak of the Second World War
and the reservoir was not finally completed until 1951, when it was officially opened on 4 September by William Girling, Chairman of the MWB, and named eponymously..
of the site is alluvium
underlain by river terrace gravels and in turn overlying the London Clay
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 12 feet (3.7 m) wide at the base and tapers to 5 feet (1.5 m) wide at the crest. The core typically extends 3 feet (90 cm) into the London Clay to form a watertight cut off.
The embankment shoulders consist of zones of ballast
and filling material. The upper embankments slopes are 1 in 2.5 externally, whilst the lower slopes to the berm
were constructed at a bank slope of 1 in 8.
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.
faced dry shaft that houses a 54 inch (137 cm) diameter vertical pipe, with draw-off pipes at four different levels. The lower end of the standpipe is connected to a 50 inch (127 cm) diameter steel outlet conduit
.
The water is conveyed to the Coppermills Water Treatment Works
for treatment, with the facility for bulk transfer to Essex and Suffolk Water.
(SSSI) , and is a major wintering ground for wildfowl and wetland
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.
London Borough of Enfield
The London Borough of Enfield is the most northerly London borough and forms part of Outer London. It borders the London Boroughs of Barnet, Haringey and Waltham Forest...
and is part of the Lee Valley Reservoir Chain
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.- Reservoirs :The following waters are located in the London Borough of Enfield and are known collectively as the Chingford Reservoirs, which are a Site of Special...
that supplies London with drinking water. It is named after William Girling OBE, a chairman of the Metropolitan Water Board (MWB). The reservoir and the nearby King George V Reservoir
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...
are known collectively as the Chingford Reservoirs
Chingford Reservoirs
The Chingford Reservoirs is the collective name for the King George V Reservoir and the William Girling Reservoir, which form part of the Lee Valley Reservoir Chain. They were constructed by John Mowlem & Co.They are a Site of Special Scientific Interest....
. The storage reservoir, which is owned by Thames Water
Thames Water
Thames Water Utilities Ltd, known as Thames Water, is the private utility company responsible for the public water supply and waste water treatment in large parts of Greater London, the Thames Valley, Surrey, Gloucestershire, Wiltshire, Kent, and some other areas of in the United Kingdom...
, is bordered by Chingford
Chingford
Chingford is a district of north east London, bordering on Enfield and Edmonton to the west, Woodford to the east, Walthamstow and Stratford to the south and Essex to the north. It is situated northeast of Charing Cross and forms part of the London Borough of Waltham Forest...
to the east and Ponders End
Ponders End
Ponders End is a place in the London Borough of Enfield, North London located in an area generally known as the Lea Valley. It is roughly located in the area either side of Hertford Road between The Ride and the Boundary Public House and Wharf Road and the Southbury railway station/Kingsway...
and Edmonton
Edmonton, London
Edmonton is an area in the east of the London Borough of Enfield, England, north-north-east of Charing Cross. It has a long history as a settlement distinct from Enfield.-Location:...
to the west, and covers 334 acres (135 hectares) with a perimeter of 3.5 miles (5.6 km). There is no public access.
History
The reservoir was conceived as part of an overall plan for the Lea ValleyLea 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...
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
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 "all those portions of the Metropolis, and its suburbs,...
. However, under the Provisions of the Metropolis Water Act of 1902, 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
John Mowlem was an 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...
(for £682,156) was accepted. The project was led by civil engineer
Civil engineer
A civil engineer is a person who practices civil engineering; the application of planning, designing, constructing, maintaining, and operating infrastructures while protecting the public and environmental health, as well as improving existing infrastructures that have been neglected.Originally, a...
, Robert Wynne-Edwards
Robert Wynne-Edwards
Sir Robert Meredydd Wynne-Edwards CBE, DSO, MC and bar was a British civil engineer and army officer. Wynne-Edwards was born in Cheltenham and educated at Giggleswick School and Leeds Grammar School before being commissioned into the Royal Welch Fusiliers at the outbreak of the First World War...
. Due to the use of mechanical scrapers and bulldozers, which were being used for the first time in British dam construction, progress was rapid. The design, by Sir Jonathan Roberts Davidson
Jonathan Davidson
Colonel Sir Jonathan Roberts Davidson, CMG, TD, MSc, MICE was a British civil engineer and army officer. Davidson pursued a professional career as an engineer which resulted in him being elected president of both the Institution of Civil Engineers and of the Smeatonian Society of Civil Engineers...
, 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 23 feet (7 m) a 66 foot (20 m) width had dropped 2 feet 4 inches (70 cm) and moved forward 13 feet (4 m). 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
Soil mechanics is a branch of engineering 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 and particles but soil may also contain organic solids, liquids, and gasses and other...
experts, Dr. Herbert Chatley and Professor Karl Terzaghi, 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
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
. 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
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
and the reservoir was not finally completed until 1951, when it was officially opened on 4 September by William Girling, Chairman of the MWB, and named eponymously..
Description
The geologyGeology
Geology is the science comprising the study of solid Earth, the rocks of which it is composed, and the processes by which it evolves. Geology gives insight into the history of the Earth, as it provides the primary evidence for plate tectonics, the evolutionary history of life, and past climates...
of the site is alluvium
Alluvium
Alluvium is loose, unconsolidated soil or sediments, eroded, deposited, and reshaped by water in some form in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel...
underlain by river terrace gravels and in turn overlying the London Clay
London Clay
The London Clay Formation is a marine geological formation of Ypresian age which crops out in the southeast of England. The London Clay is well known for the fossils it contains. The fossils from the Lower Eocene indicate a moderately warm climate, the flora being tropical or subtropical...
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 12 feet (3.7 m) wide at the base and tapers to 5 feet (1.5 m) wide at the crest. The core typically extends 3 feet (90 cm) into the London Clay to form a watertight cut off.
The embankment shoulders consist of zones of ballast
Track ballast
Track ballast forms the trackbed upon which railway sleepers or railroad ties are laid. It is packed between, below, and around the ties. It is used to facilitate drainage of water, to distribute the load from the railroad ties, and also to keep down vegetation that might interfere with the track...
and filling material. The upper embankments slopes are 1 in 2.5 externally, whilst the lower slopes to the berm
Berm
A berm is a level space, shelf, or raised barrier separating two areas. Berm originates in the Middle Dutch and German berme and came into usage in English via French.- History :...
were constructed at a bank slope of 1 in 8.
Inflow
Water is pumped from the River Lee DiversionRiver 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 :...
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 graniteGranite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
faced dry shaft that houses a 54 inch (137 cm) diameter vertical pipe, with draw-off pipes at four different levels. The lower end of the standpipe is connected to a 50 inch (127 cm) diameter steel outlet conduit
Aqueduct
An aqueduct is a water supply or navigable channel constructed to convey water. In modern engineering, the term is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose....
.
The water is conveyed to the Coppermills Water Treatment Works
Coppermill Stream
The Coppermill Stream is located in the London Borough of Waltham Forest at Walthamstow in an area generally known as the Lea Valley. It is a minor tributary of the River Lea and approximately long. The stream is part of a Site of Metropolitan Importance...
for treatment, with the facility for bulk transfer to Essex and Suffolk Water.
Ecology
The water is a Site of Special Scientific InterestSite of Special Scientific Interest
A Site of Special Scientific Interest is a conservation designation denoting a protected area in the United Kingdom. SSSIs are the basic building block of site-based nature conservation legislation and most other legal nature/geological conservation designations in Great Britain are based upon...
(SSSI) , and is a major wintering ground for wildfowl and wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....
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.