|
The River Witham is a river almost entirely in the county of Lincolnshire in the east of England. It rises south of Grantham close to South Witham at , passes Lincoln at and at Boston, , flows into The Haven, a tidal arm of The Wash, near RSPB Frampton Marsh. The name "Witham" seems to be extremely old and of unknown origin.〔; see Old European hydronymy〕 Archaeological and documentary evidence shows the importance of the Witham as a navigation from the Iron Age onwards. From Roman times it was navigable to Lincoln, from where the Fossdyke was constructed to link it to the River Trent. The mouth of the river moved in 1014 following severe flooding, and Boston became important as a port. From 1142 onwards, sluices were constructed to prevent flooding by the sea, and this culminated in the Great Sluice, which was constructed in 1766. It maintained river levels above Boston, and helped to scour the channel below it. The land through which the lower river runs has been the subject of much land drainage, and many drains are connected to the Witham by flood doors, which block them off if river levels rise rapidly. The river is navigable from Brayford Pool in Lincoln to Boston, with Locks only in Lincoln, at Bardney and at the Grand Sluice. Passage through the Grand Sluice lock is restricted to short periods when the tidal levels are suitable. The river provides access for boaters to the Witham Navigable Drains, to the north of Boston, and to the South Forty-Foot Drain to the south, which was reopened as part of the Fens Waterways Link, a project to link the river to the River Nene near Peterborough. From Brayford Pool, the Fossdyke Navigation still links to the Trent. ==Route== The Witham's course is one of the strangest of British rivers, the result of glaciation (and possibly isostatic rebound) redirecting older rivers. The source of the river is on high ground near South Witham, Lincolnshire, from whence it flows generally north, very close to and almost parallel with the Trent around the outskirts of Newark, before turning east towards Lincoln. The upper waters are important for agricultural water extraction, and also for coarse fish such as roach, common bream and pike; small mammals like water voles, and native crayfish.〔 A gap in the limestone near Ancaster is believed to represent an earlier, straighter course of the upper river towards Boston, leading towards what is now the Slea. From near Claypole to Beckingham, a distance of about three miles, the river forms the boundary between Lincolnshire and Nottinghamshire. From North Witham to Long Bennington, the river largely follows the line of the A1, which crosses the river just north of the B6403 junction near Easton. In Lincoln, the river flows into Brayford Pool and exits along a narrow channel that passes under the mediaeval High Bridge.〔 The bridge not only restricts navigation due to its small size, but the volume of water that can pass through the gap is limited in times of flood. This is alleviated by the Syncil Dyke, which leaves the main channel at Bargate Weir and runs for through the industrial areas to the south of the main city centre. It used to rejoin the main channel at Stamp End, but was re-routed into the South Delph, a drainage ditch constructed by John Rennie in the early 19th century that joins the main channel below Bardney lock. The origins of the Sincil Dyke are unknown, but it is known to have been used as a drainage channel in the mid-13th century and is thought to be pre-medieval or even Roman. Parts of it were culverted in 1847 to allow the construction of Lincoln Central railway station. From Lincoln, the river again turns first east, then south, making a cut through an belt of upland known as the Lincoln Gap. This section is again believed to have been a lower course of the Trent during and before periods of glaciation. From Dogdyke near Coningsby to Boston, the north bank of the (river ) was used by a section of the Great Northern Railway from Lincoln to Boston. A long-distance footpath, the Water Rail Way, follows the course of the river from Lincoln to Boston. The path uses sections of the river towpath and abandoned railway tracks, and has been opened in stages, with the final being completed in September 2008. The path is now part of Route 1 of the National Cycle Network and features a number of sculptures along its length, each commissioned from local artists. They include Lincoln longwool sheep at Stixwould, Lincoln red cows at Washingborough, and Lincoln curly pigs, which became extinct in 1972, at Southrey. 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「The River Witham is a river almost entirely in the county of Lincolnshire in the east of England. It rises south of Grantham close to South Witham at , passes Lincoln at and at Boston, , flows into The Haven, a tidal arm of The Wash, near RSPB Frampton Marsh. The name "Witham" seems to be extremely old and of unknown origin.; see Old European hydronymy Archaeological and documentary evidence shows the importance of the Witham as a navigation from the Iron Age onwards. From Roman times it was navigable to Lincoln, from where the Fossdyke was constructed to link it to the River Trent. The mouth of the river moved in 1014 following severe flooding, and Boston became important as a port.From 1142 onwards, sluices were constructed to prevent flooding by the sea, and this culminated in the Great Sluice, which was constructed in 1766. It maintained river levels above Boston, and helped to scour the channel below it. The land through which the lower river runs has been the subject of much land drainage, and many drains are connected to the Witham by flood doors, which block them off if river levels rise rapidly. The river is navigable from Brayford Pool in Lincoln to Boston, with Locks only in Lincoln, at Bardney and at the Grand Sluice. Passage through the Grand Sluice lock is restricted to short periods when the tidal levels are suitable. The river provides access for boaters to the Witham Navigable Drains, to the north of Boston, and to the South Forty-Foot Drain to the south, which was reopened as part of the Fens Waterways Link, a project to link the river to the River Nene near Peterborough. From Brayford Pool, the Fossdyke Navigation still links to the Trent.==Route==The Witham's course is one of the strangest of British rivers, the result of glaciation (and possibly isostatic rebound) redirecting older rivers. The source of the river is on high ground near South Witham, Lincolnshire, from whence it flows generally north, very close to and almost parallel with the Trent around the outskirts of Newark, before turning east towards Lincoln. The upper waters are important for agricultural water extraction, and also for coarse fish such as roach, common bream and pike; small mammals like water voles, and native crayfish. A gap in the limestone near Ancaster is believed to represent an earlier, straighter course of the upper river towards Boston, leading towards what is now the Slea. From near Claypole to Beckingham, a distance of about three miles, the river forms the boundary between Lincolnshire and Nottinghamshire. From North Witham to Long Bennington, the river largely follows the line of the A1, which crosses the river just north of the B6403 junction near Easton.In Lincoln, the river flows into Brayford Pool and exits along a narrow channel that passes under the mediaeval High Bridge. The bridge not only restricts navigation due to its small size, but the volume of water that can pass through the gap is limited in times of flood. This is alleviated by the Syncil Dyke, which leaves the main channel at Bargate Weir and runs for through the industrial areas to the south of the main city centre. It used to rejoin the main channel at Stamp End, but was re-routed into the South Delph, a drainage ditch constructed by John Rennie in the early 19th century that joins the main channel below Bardney lock. The origins of the Sincil Dyke are unknown, but it is known to have been used as a drainage channel in the mid-13th century and is thought to be pre-medieval or even Roman. Parts of it were culverted in 1847 to allow the construction of Lincoln Central railway station. From Lincoln, the river again turns first east, then south, making a cut through an belt of upland known as the Lincoln Gap. This section is again believed to have been a lower course of the Trent during and before periods of glaciation. From Dogdyke near Coningsby to Boston, the north bank of the (river ) was used by a section of the Great Northern Railway from Lincoln to Boston.A long-distance footpath, the Water Rail Way, follows the course of the river from Lincoln to Boston. The path uses sections of the river towpath and abandoned railway tracks, and has been opened in stages, with the final being completed in September 2008. The path is now part of Route 1 of the National Cycle Network and features a number of sculptures along its length, each commissioned from local artists. They include Lincoln longwool sheep at Stixwould, Lincoln red cows at Washingborough, and Lincoln curly pigs, which became extinct in 1972, at Southrey.」の詳細全文を読む スポンサード リンク
|