Editing Upper Rhine (section)

== Interventions ==
=== Straightening ===
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[[File:Hans Thoma - Landschaft am Oberrhein (1916).jpg|thumb|right|{{lang|de|Landschaft am Oberrhein}}, artwork by [[Hans Thoma]], 1916]]
[[File:Die-Wege-des-Rheins.jpg|thumb|right|Straightening monument viewed from the north]]
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In 1685, [[Louis XIV]] started a project to move the Upper Rhine, change its course and drain the [[floodplain]], in order to gain land.  By 1840, the river had been moved up to {{convert|1.5|km|mi}} to the east, taking territory away from Baden.  Around 1790, large parts of the Rhine Valley were deforested, creating arable land, fields and pasture to feed the population. The Upper Rhine was [[River engineering|straightened]] between 1817 and 1876 by [[Johann Gottfried Tulla]] and changed from a relatively sluggish [[meander]]ing river with major and many smaller branches into a fast flowing stream flanked by embankments.  The length of the Upper Rhine was reduced by {{convert|81|km|mi}}.  Some cut-off river arms and ox-bows remain; they are typically called the 'Old Rhine' ({{langx|de|Altrhein}}) or {{lang|de|Gießen}} (similar to the [[Alter Rhein|Old Rhine]] ({{lang|de|Alter Rhein}}) in the [[Alpine Rhine Valley]], where the Rhine was also straightened).

=== Canalising and dams ===
The Rhine between Basel and [[Iffezheim]] is almost entirely canalised.  On a stretch of {{convert|180|km|mi}}, there are 10 [[dams]], provided with [[hydropower station]]s and [[lock (water transport)|lock]]s.  Between Basel and [[Breisach]], the old river bed carries hardly any water; almost all water is diverted through the [[Grand Canal d'Alsace]] on the French side, to ensure safe shipping and hydropower generation around the clock.  Only when there is a large supply of water, then the old river bed will receive more water than the canal.  France gained the right to do this in the 1919 Treaty of Versailles; the right applies to the segment between Basel and [[Neuburgweier]]/Lauterbourg, where the Rhine forms the border between France and Germany.

The straightening (1817–76) and  channeling (1928–77) reduced the [[water table]] by up to {{convert|16|m|ft|0}} and thus had a negative effect on [[flora]] and [[fauna]].  [[Gravel]] is also missing from the river, due to the dams.  This has caused erosion below the dam at Iffezheim.  To counter this, {{convert|173000|m3|ft3}} per year of a mixture of sand and gravel with an average grain diameter of {{convert|20|mm|in}} (corresponding to the local sediment transport capacity) has been dumped into the river, since 1978, using two motorized barges.
[[File:Rheinstaustufe bei Breisach.jpg|thumb|center | 580px | Weir at Breisach; to the left a lock; to the right a small power station under construction]]

=== Integrated Rhine Programme (IRP) ===
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[[File:20160601-00481-IRP-Weil-Breisach-I.jpg|thumb|right|Integrated Rhine Programme (IRP) Polder under construction near Efringen-Kirchen]]
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The Upper Rhine plays a key role in [[flood control]] on the Middle and [[Lower Rhine]].  As a result of the straightening of the Upper Rhine, [[floods]] from the [[Alps]] now reach the Middle Rhine much faster than in the past.  Thus, the risk of such a peak coinciding with a flood peak of Neckar, [[Moselle]] or Main has increased.  About {{convert|123|km2|mi2}} of floodplain have been lost.  Authorities in riparian states of France, [[Baden-Württemberg]] and [[Rhineland-Palatinate]] have launched the ''Integrated Rhine Programme'', a framework for designating water retention areas. to combat downstream flooding.  A French-German treaty was concluded in 1982, in which the parties agreed to restore the retention capacity on the stretch below Iffezheim to the level it had before the area was developed.

This means:
For the stretch between Iffezheim and the mouth of the Neckar, attenuation of the apex of a 200-year flood (i.e. a flood that statistically occurs once in 200 years) of the Rhine to a discharge of {{convert|5000|m3/s|cuft/s}} at the Maxau gauge station, that is, a reduction from {{convert|5700|m3/s|cuft/s}} to {{convert|5000|m3/s|cuft/s}}.
* for the stretch below the mouth of the Neckar, attenuation of the apex of a 220-year flood to a discharge of {{convert|6000|m3/s|cuft/s}} at the Worms gauge station, that is, a reduction from {{convert|6800|m3/s|cuft/s}} to {{convert|6000|m3/s|cuft/s}}.

For this purpose the following measures are planned and partially implemented:
* By France: Special operations power stations on the Rhine and construction of two polders [[Erstein]] and [[Moder (river)|Moder]]
* By Baden-Württemberg: construction of about 13 polders
* By Rhineland-Palatinate: construction of polders and relocating levees

The effectiveness of the flood protection measures was verified using a computer model.  The State Institute for the Environment, Nature Protection and Measurements in Baden-Württemberg carried out forecast calculations with the help of a mathematical "synoptic flood progression model".  The analysis of the calculations and the evaluation of the results were made on the basis of the requirements and methods set by the international Flood Study Commission for the Rhine.  The implementation of the proposed flood control measures on the Upper Rhine can prevent the occurrence of a 200-year-flood between Iffezheim and Bingen, with an overall economic loss estimated at around 6.2 billion euros.