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The River Little Ouse is a river in the east of England, a tributary of the River Great Ouse. For much of its length it defines the boundary between Norfolk and Suffolk. It rises east of Thelnetham, very close to the source of the River Waveney - which flows eastwards while the Little Ouse flows west. The village with the curious name of Blo' Norton owes this name to the river - it was earlier known as ''Norton Bell-'eau'', from being situated near this 'fair stream'. In this area the river creates a number of important wetland areas such as at Blo' Norton and Thelnetham Fen and areas managed by the Little Ouse Headwaters Project.〔(Blo' Norton and Thelnetham Fen ), SSSI citation, Natural England. Retrieved 2013-01-31.〕 The course continues through Rushford, Thetford, Brandon, and Hockwold before the river joins the Great Ouse north of Littleport in Cambridgeshire. The total length is about . The river is currently navigable from the Great Ouse to a point above Brandon. ==Its origin== The most distinctive feature of the headwaters of the Little Ouse and the Waveney is the valley in which they flow; the Little Ouse westwards and the Waveney, eastwards. It has a broad, fenny bottom, lies at an altitude of up to and both rivers rise in the fen alongside the B1113 road, between South Lopham and Redgrave. (). The explanation of this oddity is that the valley was formed, not by these rivers but by water spilling from Lake Fenland. This was a periglacial lake of the Devensian glacial, fifteen or twenty thousand years ago. The ice sheet closed the natural drainage from the Vale of Pickering, the Humber and The Wash so that a lake of a complex shape formed in the Vale of Pickering, the Yorkshire Ouse valley, the lower Trent valley and the Fenland basin. This valley was its spillway into the southern North Sea basin, thence to the English Channel basin, which at the time, contained no sea. The downstream end of the Little Ouse has changed much over the centuries. In the Fens and Norfolk Marshland, it was quite possible for the course of a river to change as the result of a flooding episode so it is not surprising to find that the Great Ouse used to enter The Wash by way of the Old Croft River, the Wellstream and Wisbech (the Ouse beach). The modern lower Great Ouse was then the lower part of the Little Ouse. On this occasion, the change was artificial. The 17th century drainers under Cornelius Vermuyden dug the Old Bedford River between the Great Ouse at Earith and what had hitherto been the Little Ouse at Denver. A link was made for the Great Ouse between Littleport 1 and the Little Ouse at Brandon Creek () and both the drainage and the navigation were directed towards King's Lynn rather than Wisbech. 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「River Little Ouse」の詳細全文を読む スポンサード リンク
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