Three Mills Lock, also known as the Prescott Lock is a lock on the Prescott Channel on the River Lea in

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

. The project was led by

British Waterways British Waterways, often shortened to BW, was a statutory corporation wholly owned by the government of the United Kingdom. It served as the navigation authority for the majority of canals and a number of rivers and docks in England, Scotla ...

and the lock officially opened on 5 June 2009. The lock cuts off this section of the Bow Back Rivers from the tide, creating new opportunities for leisure boats, water taxis, trip boats and

floating restaurant A floating restaurant is a vessel, usually a large steel barge or hulk, used as a restaurant on water. The '' Jumbo Kingdom'', formerly located at Aberdeen in Hong Kong, was at one time the world's largest floating restaurant, until it sank a ...

s. It also helps freight traffic such as barges carrying construction materials to the sites of the 2012 Olympics and

Stratford City Stratford City is a mixed-use development project in Stratford, London, England, to the north of Stratford town centre. The main developers are the Westfield Group and Lendlease. Stratford City is the name given to the urban community centred ...

Design

Three Mills Lock has been built on the Prescott Channel, which was constructed in the 1930s as part of a scheme for flood prevention and the creation of employment. It bypassed the

tide mills Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables c ...

at Three Mills, and included a sluice structure, which was used to control levels in the Bow Back Rivers much as the present structure is. This original structure became inoperative by the mid 1960s, and was removed in the 1980s, as the Bow Back Rivers had been classified as Remainder Waterways by the 1968 British Waterways Act, and there was no funding for maintenance. A consequence of this was that the rivers reverted to being tidal. This made navigation difficult, since there was not enough water at low tide, and at high tide, there was insufficient headroom, due to the low level of the

Northern Outfall Sewer The Northern Outfall Sewer (NOS) is a major gravity sewer which runs from Wick Lane in Hackney to Beckton sewage treatment works in east London; most of it was designed by Joseph Bazalgette after an outbreak of cholera in 1853 and the " Gre ...

, which crosses the waterways. With the selection of the island formed by the City Mills River and the Lee Navigation as the site for the

2012 London 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 ...

main stadium, restoration of the channels was thought to be an important part of the site development, particularly as it might allow some of the construction materials to be delivered by barge. A new lock and sluice structure was therefore designed for the Prescott Channel, with a second sluice on the Three Mills Wall River to prevent tidal water flowing backwards through the Three Mills tide mill. Prior to the development, tidal levels on the Bow Back Rivers reached above ordnance datum (AOD) on spring tides. The sluice is designed to stabilise levels at AOD, and the lock structure therefore has to cope with levels on the downstream side which might be higher or lower than those on the upstream side. The new lock is long, wide and deep, and is able to hold two 350-tonne barges (the present locks on the nearby

Lee Navigation The Lee Navigation is a canalised river incorporating the River Lea (also called the River Lee along the sections that are navigable). It flows from Hertford Castle Weir to the River Thames at Bow Creek; its first lock is Hertford Lock and it ...

limit barges to about 120 tonnes).''Notes and News''
(April 2007) (Greater London Industrial Archaeology Society) The tidal range is handled by the use of hydraulic sector gates at both ends of the lock, and the structure incorporates two large rising radial gates for flood control in the Bow Back Rivers. A site in the river, just south of this lock is the resting place of the remains of the

Euston Arch The Euston Arch, built in 1837 (and demolished in 1962), was the original entrance to Euston station, facing onto Drummond Street, London. The arch was demolished when the station was rebuilt in the 1960s, but much of the original stone was later ...

. A footbridge for pedestrians and a fish pass for migrating fish is incorporated into the design of the lock, and British Waterways claim there will be associated improvements to the navigation and tow path, as a part of the Olympic legacy.

Impact

The effect of building the lock, together with the Three Mills Wall River Weir is to lock out the tide just north of the House Mill. This means that this section of the Bow Back Rivers has ceased to be tidal. The lock has been constructed so that barges from two large building projects (the London 2012 Olympics and

) may pass through the lock, taking spoil out and delivering building materials on to the sites, via a new wharf on the Waterworks River. The barges will pass directly into the northern section of Bow Creek to the

River Thames The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the ...

. The head of water created by the lock may be used to fill the mill pound and once more allow operation of the Three Mills tidal mill.

History

An unexploded ''Hermann'' bomb from

World War II 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 World War II by country, vast majority of the world's countries—including all of the great power ...

was found on 2 June 2008. The bomb was made safe, in a controlled explosion, after five days of disruption to tube and rail services. The lock opened officially on Friday 5 June 2009, and has begun limited operations, but the expected use of the lock is just "one barge a week".London 2012 Olympic Games: Canal barge plans 'failing'
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Transport links

West Ham West Ham is an area in East London, located east of Charing Cross in the west of the modern London Borough of Newham. The area, which lies immediately to the north of the River Thames and east of the River Lea, was originally an ancient ...

and

Bromley-by-Bow Bromley, commonly known as Bromley-by- Bow, is a district in the London Borough of Tower Hamlets in East London, located on the western banks of the River Lea, in the Lower Lea Valley in East London. The area is distinct from Bow, which l ...

are the nearest

London Underground stations The London Underground is a rapid transit, metro system in the United Kingdom that serves Greater London and the home counties of Buckinghamshire, Essex and Hertfordshire. Its first section opened in 1863, making it the oldest underground metro ...

. The nearest

Docklands Light Railway stations Dockland or Docklands are areas occupied by, or in the neighbourhood of maritime docks, sometimes described as a Sailortown (dockland). The term is more common in Britain and British Commonwealth. Specifically the term may refer to: * Aarhus D ...

are '' Bow Church'' and '' Pudding Mill Lane''

Bibliography

* *

References