46-715: The Middlesex Filter Beds Weir , or Lea Bridge Road Weir , marks the start of the Hackney Cut , an artificial channel of the River Lee Navigation built in 1770, in the London Borough of Hackney . The weir lies between the former Middlesex Filter Beds – now a nature reserve – and the Thames Water treatment works at Lea Bridge Road. Excess water from the Navigation passes over
92-490: A 1-in-1000-year event. The Environment Agency was examining the Thames Barrier for its potential design life under climate change, with early indications being that subject to appropriate modification, the Thames Barrier would be capable of providing continued protection to London against rising sea levels. A UK Environment Agency review in 2023 said that new climate models showed heightened risk of flooding, implying
138-608: A deep depression forms to the north of Scotland and progresses across the North Sea and south-easterly towards southern Scandinavia. When such a surge coincides with a high spring tide , the high winds associated with the depression can funnel the water up the Thames Estuary and cause surges of up to 3.5 metres (11.6 feet). The planners assessed that in the absence of a barrier, such a surge could inundate 45 square miles (117 km ) of land, put hospitals, power stations and
184-451: A half-lock, but was rebuilt to handle larger barges in the 1850s, and now only Old Ford Lock , which is actually a duplicated pair, remains. The River Lea (or Lee) has a long history of use for navigation, with records indicating that the Abbot of Waltham was authorised to make improvements in 1190, and evidence for tidal gates at Bow from the reign of King Edward I , when Henry de Bedyk,
230-455: A new barrier to be looked into immediately. The Environment Agency responded that it did not plan to replace the Thames Barrier before 2070, as it was designed with an allowance for sea level rise of 8 mm (0.31 in) per year, which has not happened in the intervening years. At the time, the barrier was around halfway through its designed lifespan. The standard of protection it provides will gradually decline over time after 2030, from
276-521: A width of 18.5 feet (5.64 m) in 1935, but retained their names, the small lock being shallower than the large lock. Further rebuilding had to take place during the Second World War after they were hit by a bomb on 19 October 1940, which also destroyed the lock houses. New lock houses were built in 1946, and were sold in the 1990s, after which they were used as the location for the television programme " The Big Breakfast ". From 1829, water
322-579: A working model. The novel rotating cylinders were based on the design of the taps on his gas cooker . The barrier was designed by Rendel, Palmer and Tritton for the Greater London Council and the concept tested at the Hydraulics Research Station , Wallingford. The site at New Charlton was chosen because of the relative straightness of the banks, and because the underlying river chalk was strong enough to support
368-674: A year. Released in 2005, a study by four academics contained a proposal to supersede the Thames Barrier with a more ambitious 16 km (10 mi) long barrier across the Thames Estuary from Sheerness in Kent to Southend-on-Sea in Essex . In November 2011, a new Thames Barrier, further downstream at Lower Hope between East Tilbury in Essex and Cliffe in Kent, was proposed as part of
414-677: Is a stub . You can help Misplaced Pages by expanding it . Hackney Cut The Hackney Cut is an artificial channel of the Lee Navigation built in England in 1769 by the River Lea Trustees to straighten and improve the Navigation. It begins at the Middlesex Filter Beds Weir , below Lea Bridge , and is situated in the (modern) London Borough of Hackney . When built it contained two pound locks and
460-650: Is in the New Charlton area of the Royal Borough of Greenwich . Flooding in London has been a problem since Roman times. In 1954, the Waverley Committee, established to investigate the serious North Sea flood of 1953 which affected parts of the Thames Estuary and parts of London, recommended that "as an alternative to raising the banks, the possibility and cost of erecting a structure across
506-555: The London Gazette and other newspapers that they wanted to borrow £35,000 to finance the improvements, to which there was a huge response. Some £161,500 was offered, and subscribers had to be picked by a ballot. Work on the whole scheme progressed quickly, and the contract for the Hackney Cut was awarded to Jeremiah Ilsley on 18 January 1768. He was probably acting as a public works contractor, since he also had contracts for
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#1732791817254552-555: The London Underground out of action and cause damage estimated in 1966 at £2 billion (about £50 billion at 2020 prices). The barrier was designed to provide a flood defence capable of resisting a once in 1000 year surge tide at a base date of 2030. The concept of the rising sector gates was devised by (Reginald) Charles Drapeer. In 1969, from his parents' house in Pellatt Grove, Wood Green , London, he constructed
598-584: The Normal Tidal Limit , in periods of very high fluvial flow the tidal influence can be seen as far upstream as East Molesey on the Thames. As of May 2024 , there have been 221 flood defence closures. The barrier was closed twice on 9 November 2007 after a storm surge in the North Sea which was compared to the one in 1953. The main danger of flooding from the surge was on the coast above
644-521: The Thames Hub integrated infrastructure vision . The barrier would incorporate turbines to generate renewable energy and include road and rail tunnels, providing connections from Essex to a major new Thames Estuary Airport on the Isle of Grain . In 2019 architects Lifschutz Davidson Sandilands and marine engineers Beckett Rankine launched a proposal for a pedestrian and cycle bridge located next to
690-644: The Thames and Medway Canal and Harecastle Tunnel on the Trent and Mersey Canal , worked on the waterworks project from 1829 until 1834. In 1824, George Duckett, the son of Sir George Duckett, 1st Baronet who had owned the Stort Navigation , obtained an Act of Parliament to link the Hackney Cut to the Regents Canal , which he hoped would result in much of the trade which passed onto the Thames from
736-507: The floodplain of most of Greater London from exceptionally high tides and storm surges moving up from the North Sea . It has been operational since 1982. When needed, it is closed (raised) during high tide; at low tide, it can be opened to restore the river's flow towards the sea. Built about 2 miles (3.2 kilometres) east of the Isle of Dogs , its northern bank is in Silvertown in the London Borough of Newham and its southern bank
782-621: The "more stable tidal conditions … in central London … will help the vessels taking part". The barrier was originally commissioned by the Greater London Council under the guidance of Ray Horner. After the 1986 abolition of the GLC it was operated successively by Thames Water Authority (dissolved 1989) and then the National Rivers Authority until April 1996 when it passed to the Environment Agency . The barrier
828-463: The Lee Navigation being re-routed to Regents Canal Dock. The Hertford Union Canal , which was 1.25 miles (2.0 km) long, included three locks, and joined the cut a short distance above Old Ford Locks, opened in 1830 but failed to attract much traffic, due to the level of tolls. The Hackney Cut is 2 miles (3.2 km) long from Lea Bridge road bridge to Old Ford Locks. Excess water from
874-470: The Navigation in 1762. It was tidal, as the course of the Old River Lee was affected by tides from the Thames up to this point. The new cut was protected by Lea Bridge Half Lock, a single set of gates just below the junction. Homerton Lock, which was also known as Hackney Brick Cistern Lock, was about one-third of the way along the cut, while Old Ford Lock was located just above where the cut rejoined
920-538: The Navigation passes over the weir into the former natural channel of the River Lea that passes in a large meander to the east of the modern water course, forming the boundary with the London Borough of Waltham Forest . The old course used to rejoin the Navigation below Old Ford Lock , but this route was modified by the construction of Carpenter's Road Lock on the Bow Back Rivers in 1930. Prescott Channel
966-504: The Thames Barrier, where evacuations took place, but the winds abated a little and, at the Thames Barrier, the 9 November 2007 storm surge did not completely coincide with high tide. On 20 August 1989, hours after the Marchioness disaster , the barrier was closed against a spring tide for 16 hours "to assist the diving and salvage operations". The barrier has survived 15 boat collisions without serious damage. On 27 October 1997,
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#17327918172541012-645: The Thames Barrier; the scheme, called the Thames Barrier Bridge, was promoted as the only location in east London where a low-level opening bridge across the Thames could have relatively moderate opening spans of about 60 m (200 ft). In a January 2013 letter to The Times , a former member of the Thames Barrier Project Management Team, Dr Richard Bloore, stated that it was not designed with increased storminess and sea level rises in mind, and called for
1058-547: The Thames which could be closed in a surge should be urgently investigated". A number of designs were put forward, from a huge road viaduct with two 500 foot (150 m) sluice gates crossing the Thames at Crayfordness to flap gates lying on the river bed and floated up by compressed air . By 1965, when the Greater London Council (GLC) took over responsibility, two major schemes were under consideration, costed at £24 million and £41 million respectively (£500 million and £800 million at 2020 prices). In 1966, Sir Hermann Bondi
1104-587: The Waltham Cut and part of the Limehouse Cut , and so must have been managing a large labour force. He was to be paid 3 old pence (3d, 1.25p) per yard for the Hackney Cut, considerably less than the rate for the Limehouse Cut, which was 7d, and was given four months in which to complete the excavations. Contracts for the construction of the locks were separate to the excavation, and the work on
1150-402: The barrier site in 1974 and progressed in two phases. The southern piers (9 to 6) were built first, with river traffic diverted to the north side, then traffic routed through the completed southern spans whilst the north side piers (1 to 5) were built. During construction of the piers, precast concrete sills were built in a cofferdam on the north side of the river and floated out and sunk between
1196-405: The barrier was damaged when the dredger MV Sand Kite hit one of the piers in thick fog. As the ship started to sink she dumped her 3,300-tonne load of aggregate, finally sinking by the bow on top of one of the barrier's gates, where she lay for several days. Initially the gate could not be closed as it was covered in a thick layer of gravel. A longer-term problem was the premature loss of paint on
1242-575: The barrier. The Thames Barrier and Flood Prevention Act, authorising construction, was passed in 1972. In 1974, the GLC placed the two major construction contracts. Civil construction was undertaken by a Costain / Hollandsche Beton Maatschappij / Tarmac Construction consortium. A separate contract for the gates and operating machinery was placed with the Davy Cleveland Barrier Consortium, formed by Davy McKee Ltd of Sheffield and Cleveland Bridge UK Ltd . Work began at
1288-549: The flat side of the gate caused by abrasion. The vessel was refloated in mid-November 1997. The annual full test closure in 2012 was scheduled for 3 June to coincide with the Thames pageant celebrating the Diamond Jubilee of Elizabeth II . Environment Agency said the pageant provided "a unique opportunity to test its design for a longer period than we would normally be able to", and performance under conditions of "a higher water level upstream than downstream"; also that
1334-502: The navigation was rebuilt so that it was level from Tottenham to Old Ford, and the lock was then redundant, but was retained to help protect the navigation below it in times of flood. It was removed in 1931, when it was superseded by a new structure with vertical guillotine gates, located a little further upstream. These became redundant with the construction of the Thames Barrier , and the gates were removed in 1987. Homerton lock
1380-498: The navigation. Among other things, it removed the restriction on the maximum load that could be carried by barges. This had been set at 40 tons in 1805, but with the clause removed, the navigation between the Thames and Tottenham was gradually rebuilt to take 100-ton barges. Lea Bridge Lock remained in operation until 1853, when it was demolished. It was replaced by Pond Lane Lock, which was built in 1865 at Cow Bridge, about halfway between Lea Bridge and Homerton Lock. Seven years later,
1426-410: The old course of the river. The lock was semi-tidal, as the level on this section of the river was maintained by Bow tidal gates, but spring tides often flowed over the top of the gates and the locks which supplemented them after 1850, continuing to do so until the installation of extra flood walls and higher flood gates in 2000. An Act of Parliament obtained in 1850 paved the way for a major upgrade of
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1472-500: The openings are circular segments in cross section, and they operate by rotating, raised to allow "underspill" to allow operators to control upstream levels and a complete 180 degree rotation for maintenance. All the gates are hollow and made of steel up to 40 millimetres (1.6 in) thick. The gates are filled with water when submerged and empty as they emerge from the river. The four large central gates are 20.1 metres (66 ft) high and weigh 3,700 tonnes each. Four radial gates by
1518-613: The piers to form the gate recesses, with access tunnels at the upstream and downstream ends. The gates of the barrier were fabricated in sections at Cleveland Bridge's Darlington works and assembled at Port Clarence on the River Tees . The gates, gate arms and rocking beams were transported from the Tees to the Thames by barge and lifted into position by two very large floating cranes operated by Neptun of Hamburg (now part of Smit International ). The mechanical and hydraulic machinery
1564-405: The prior at Halliwell Priory and owner of the nearby tide mills, erected a structure some time before 1307. River levels were managed by flash locks or sluices, and as the volumes of traffic using the river increased, there was friction between the bargees and the millers, since use of a flash lock affected the head of water available at the adjacent mill. In 1765, the commissioners responsible for
1610-477: The river asked the engineer John Smeaton to survey the river and make recommendations for its improvement. Smeaton produced his report in September 1766, in which he recommended that the flash locks should be replaced by pound locks with two sets of gates, and that a number of new cuts should be built, including what became known as the Hackney Cut from Lea Bridge to Old Ford. The commissioners advertised in
1656-415: The river banks, also about 30 metres (100 ft) wide, can be lowered. These gate openings, unlike the main six, are non-navigable. A Thames Barrier flood defence closure is triggered when a combination of high tides forecast in the North Sea and high river flows at the tidal limit at Teddington Lock indicate that water levels would exceed 16 feet (4.9 m) in central London. Though Teddington marks
1702-431: The two locks of the Hackney Cut was given to Henry Holland, a bricklayer from Piccadilly, on 23 April 1768. Despite tight schedules, the work seems to have been completed on time, and the Hackney Cut opened for traffic on 7 August 1769. At the northern end of the cut, the river flowed to the east, through a weir now known as Middlesex Filter Beds Weir. Beside it was Hackney Waterworks Lock, the third pound lock to be built on
1748-540: The weir into the former natural channel of the River Lee that passes in a large loop to the east of the modern water course, as the Old River Lea . The natural water course travels 2 miles (3.2 km) and rejoins the Navigation below Old Ford Lock . 51°33′42″N 0°02′40″W / 51.5617°N 0.0445°W / 51.5617; -0.0445 This article about a London building or structure
1794-552: Was abstracted at Lea Bridge, from the natural watercourse, by the East London Waterworks Company , to avoid the increasing pollution of the Navigation. The waterworks was located to the south of Old Ford Locks, and the company built a canal in 1830 which ran along the east bank of the Hackney Cut to transfer water from Lea Bridge for processing. William Hoof , who had gained a reputation as a specialist tunnelling contractor, after working on Strood Tunnel for
1840-406: Was asked to take an independent view of the situation. He considered the estimated construction costs and the probability of a flood and of damage if the barrier was not built. He strongly recommended that a barrier should be built in order to avoid the catastrophe of flooding central London, and a site was agreed at Woolwich. The barrier protects central London against a storm surge , caused when
1886-534: Was built at the same time to provide a bypass around the tide mill at Three Mills , allowing the water to reach Bow Creek and the River Thames. A lock was built in the Prescott Channel in 2009. 51°33′00″N 0°01′43″W / 51.5501°N 0.0287°W / 51.5501; -0.0287 Thames Barrier The Thames Barrier is a retractable barrier system built to protect
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1932-500: Was built by Davy Loewy, Henry Berry and Vickers and trial assembled in Davy's Darnall works. Delays to the civil works required changes to the construction and installation sequence, but commissioning was relatively uneventful and the first trial operation of all the gates together was carried out on 31 October 1982. In addition to the barrier, the flood defences 18 kilometres (11 mi) down river were raised and strengthened. The barrier
1978-409: Was generally (as a median) closed twice a year but the average is still 6–7 due to the extreme of 50 times in 2013–14. This defence level allowed for long-term changes in sea and land levels as understood at that time (c. 1970). From 1982 until 19 March 2007, the barrier was raised one hundred times to prevent flooding. It is also raised monthly for testing, with a full test closure over high tide once
2024-571: Was officially opened on 8 May 1984 by Queen Elizabeth II . The barrier cost £461 million (£1.49 billion now). Total construction cost was around £534 million (£1.6 billion at 2016 prices) with an additional £100 million for river defences. Built across a 520-metre (1,710 ft) wide stretch of the river, the barrier divides the river into four 61-metre (200 ft) and two approximately 30-metre (100 ft) navigable spans. There are also four smaller non-navigable channels between nine concrete piers and two abutments. The flood gates across
2070-410: Was originally designed to protect London against a very high flood level (with an estimated return period of one hundred years) up to the year 2030, after which the protection would decrease, while remaining within acceptable limits. At the time of its construction, the barrier was expected to be used 2–3 times per year. By the mid-2000s it was being operated 6–7 times a year. In the 2010s, the barrier
2116-476: Was removed in the 1860s, following dredging of the river down to Old Ford. Old Ford Lock was rebuilt as a pair of locks on a different alignment in 1856, and the junction with the old course of the River Lee was reworked to remove an awkward bend. They were known as the small lock and the large lock, one being 15.75 feet (4.80 m) wide and the other being 18.25 feet (5.56 m) wide. Both were rebuilt with
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