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The Middle Level Navigations are a network of waterways in England, primarily used for land drainage, which lie in The Fens between the Rivers Nene and Great Ouse, and between the cities of Peterborough and Cambridge. Most of the area through which they run is at or below sea level, and attempts to protect it from inundation have been carried out since 1480. The Middle Level was given its name by the Dutch Engineer Cornelius Vermuyden in 1642, who subsequently constructed several drainage channels to make the area suitable for agriculture. Water levels were always managed to allow navigation, and Commissioners were established in 1754 to maintain the waterways and collect tolls from commercial traffic. A new main drain to Wiggenhall St Germans was completed in 1848, which provided better drainage because the outfall was lower than that at Salters Lode. Whittlesey Mere, the last remaining lake, was drained soon afterwards, using one of the first applications of John Appold's centrifugal pump, following its appearance at the Great Exhibition in 1851. Traffic on the network began to diminish after the opening of the railway through March in 1846, and fell dramatically in the early twentieth century. The last regular commercial traffic was the tanker barge ''Shellfen'', which delivered fuel oil to pumping stations until 1971. As a result of the drainage, land levels continued to fall, and in 1934 the gravity outfall at Wiggenhall St Germans was replaced by a pumping station, with three diesel engines driving diameter pumps. Its capacity was increased in 1951, and again in 1969/70, when two of the engines were replaced by electric motors. Following over 50 hours of continuous running at maximum capacity in 1998, a new pumping station was commissioned. Work on it began in 2006, and when it was completed in 2010, it was the second largest pumping station in Europe. Much of the drainage of the Middle Levels relies on pumping, and the Commissioners manage over 100 pumping stations throughout the area. Interest in restoration of the Middle Levels for leisure traffic began in 1949, and the first significant work by volunteers occurred in 1972, when they worked on the restoration of Well Creek, which finally reopened in 1975. Since then, locks have been lengthened, to allow access by modern narrowboats, as they were built for Fen Lighters, which were only long. The southern reaches became more accessible in 2006, when a low Bailey bridge was raised by soldiers from the 39 Engineer Regiment. The system is managed by Commissioners, and they are the fourth largest navigation authority in Great Britain. == History == The Middle Levels of the Fens are a low-lying area of approximately , much of which is at or below sea level.〔(【引用サイトリンク】title=St Germans Pumping Station: History )〕 Attempts to protect them from inundation and to make them suitable for agriculture began in 1480, when the Bishop of Ely, John Morton, constructed a straight cut from Stanground to Guyhirne. This provided the waters of the River Nene with a more direct route to the sea than the previous route through Benwick, Floods Ferry, March, Outwell and Wisbech. Morton's Leam, the name given to the medieval drainage ditch, was wide and deep, and much of the manual labour was provided by prisoners of war from the Hundred Years War. In 1605, Sir John Popham, who was the Lord Chief Justice at the time, began work on a drainage scheme near Upwell, and although the scheme was ultimately abandoned in 1608, Popham's Eau, his cut from the old course of the River Nene near March to the Well Creek at Nordelph remains. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Middle Level Navigations」の詳細全文を読む スポンサード リンク
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