The Rhine Basin spans across Switzerland, Germany, France and the Netherlands.
Just over 95% of the Rhine basin lies in Switzerland, Germany, France and the Netherlands. The remaining 5% of the basin lies in Belgium, Luxembourg, Austria, Liechtenstein and Italy.
Alpine Rhine and High Rhine
The Rhine has its origins in the Swiss Alps, where two tributaries (the Hinterrhine and the Vorderrhine) join together at Reichenau and flow as one river to Lake Constance. This part of the Rhine is called the Alpine Rhine. After leaving Lake Constance, the river down to the city of Basle is known as the High Rhine. Along these parts of the river - which also include the famous falls at Schaffhausen - frequent inundations, large sediment depositions and the shifting of watercourses have time and again endangered human life. Local measures were often unsuccessful, but large scale engineering works provided a solution for many of the problems when the Alpine and High Rhine were regulated and provided with a stable and regular bed. Many dams have been built, mainly for electricity generation. The largest tributary of Rhine, the Aare, joins the main stream in the High Rhine.
The reach of the river between Basle and Bingen at the Rhenish Slate Mountains is called the Upper Rhine. This partof the Rhine was originally wide and dynamic, consisting of multiple channels and meanders. Eventually, the river was regulated, mainly to stop frequent flooding. The channel was fixed between dikes and ten weirs were constructed to utilise water power. The first four of these were located in a specially constructed channel alongside the Rhine, the Grand Canal d'Alsace. After the reconstruction of the upper Rhine, navigation with large ships became possible up as far as Basle. The weirs have interrupted sediment transport. To compensate, gravel is added to the river downstream of the last weir at Iffezheim to stabilise the river bed.
Middle and Lower Rhine
Where the Rhine tries to find its way through the Rhenish Slate Mountains, the river is known as the Middle Rhine, and the following stretch down to the German-Dutch border is called the Lower Rhine. The bed of the Middle Rhine is mostly rocky. In the past, the stretch presented dangerous obstacles to shipping and claimed numerous victims. The great tributaries have now been regulated with weirs and power stations with locks. Along the Lower Rhine, flood protection has become a top priority as land and river bed subsidence has increased the danger of flooding. Subsidence has also hadnegative effects both on shipping and on ground water levels and the ecology. River engineering measures have been taken in an attempt to combat subsidence. It has recently been halted but parts of the main dikes have had to be raised several times.
At the German-Dutch border, the Rhine changes from an erosion to a sedimentation river, meaning that the Rhine Delta lies almost totally in the Netherlands. Just after entering the country, the river splits into three branches: the Waal, the Nederrijn and the Ijssel. About half of the Netherlands lies below sea level and is therefore dependent on a comprehensive, planned water management system. The land has been protected by dikes ever since the 11th century. The first measuresto regulate the discharge through the three branches of the Rhine were taken in the 19th century. Most water is discharged through Waal.
During much of the 20th century, protection against the North Sea was the main focus in the field of Dutch flood prevention but this has now changed as a result of the severe flooding along the Rhine and Meuse in 1993 and 1995. Measures are now planned to increase the discharge capacity of the river bed.
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