The different states of the Rhine
Thanking
All texts and explanations are taken from the beautiful book “RHIN VIVANT, Histoire du fleuve, des poissons et des hommes” written by Roland Carbiener, honorary professor at the University of Strasbourg, Laurent Schmitt, geographer and hydrogeomorphologist, professor at the University of Strasbourg, and Annick Schnitzler, honorary professor at the University of Lorraine. The commune of Schoenau thanks them for their agreement to use part of their work.
The handover to the commune of a rare copy of this "Carte über den Lauf des Rheins" by Mr Reinhold Hämmerle, surveyor and Rhine history enthusiast, together with his French partner Benoît Sittler, on the occasion of a conference organized in Schoenau by CEN Alsace, was the decisive factor in initiating this permanent exhibition. The commune of Schoenau is very grateful to Mr. Hämmerle for this document and thanks him.
Contents
I - The glacial Rhine (20 000 years ago)
V - The Rhine today and tomorrow
With a 185,000 km2 pond and an average discharge at its mouth of 2,200 m3 per second, the Rhine is Western’s Europe’s leading river. The so-called “Upper Rhine” segment flows between Basel and Bingen (Rhineland-Palatinate) through the “Rhine ditch”, a collapse ditch 300 kilometers long and 30-40 kilometers wide.
I - The glacial Rhine (20 000 years ago)
Stemming from the massive Alpine icecap that covered almost all of today’s Switzerland, the Rhine spreads its waters freely across the Rhine Gorge during the summer months, when some of the Alpine ice melted. The power of the floods transported large quantities of alluvium, constantly modifying the river’s shape.
An extraordinary large water table
The Upper Rhine alluvial water table is one of the largest reservoirs of drinkable water in Western Europe (80 billion m3 in the entire Rhine Gorge, including 35 billion m3 in Alsace).
The water table is an extraordinary asset, and we have a duty to protect it and maintain it at least at its current level.
It’s important to note that the water table is an essential factor in the landscape f the Rhine plain, since its roof is located at a low depth in relation to the topographical surface (between 0.5 and 2 meters), which explains the presence of the wetlands of the Grand Ried.
II - The wild Rhine
Since the end of the last ice age 12,000 years ago, the Rhine has shaped its course freely into a multitude of arms, right up to the heavy development of the early 19th century.
The Wild Rhine boasts exceptional hydro-geomorphological diversity. It was structured both longitudinally, between Basel and Lauterbourg, and laterally, with a unique range of lateral arms. In the absence if an effective system of dykes, extreme floods unfortunately caused major damages.
Location of the study area in the Alsatian edge of the Rhine Graben, hydrographic network of the Ello-Rhenan alluvial plain and longitudinal sectorization based on the fluvial style of the Rhine and the paleo-dynamic legacies of the river and the Ill (after CARBIENER, 1969, 1983a; SCHMITT et alii, 2007c).
III - The rectified Rhine
The „rectification“ of the Rhine was conceived by the Baden engineer Johan Gottfried TULLA (1770-1828).
The map of the Rhine, still wild in 1838, shows the minor bed rectified according to Tulla’s map. It shows the many bends in the river that the rectification would intersect. The work, gigantic for its time given the limited technical resources available at the time, was carried out on the Basel-Lauterbourg section between 1842 and 1876.
In addition to establishing definitive borders, the main aim of rectification was to protect people from flooding. Another major objective was to improve navigation conditions.
The rectification work intersected numerous meanders and thalweg loops on the Wild Rhine, reducing its length by 32km on the Basel-Lauterbourg stretch, or 14%, and increasing its gradient accordingly.
To protect the population from flooding, Tulla planned a system of unsinkable "high-water dykes", delimiting a flood expansion field of varying widths from 1 to 2 km. These dikes are still in operation on the German side. On the Alsatian side, the 20 km stretch between Sundhouse and Artzenheim is well preserved.
Rectification profoundly altered the functioning of the Upper Rhine. The progressive incision of the Rhine led to the outcropping of the Istein rock bar, blocking navigation to Basel from 1900 onwards.
After rectification of the minor bed, the thalweg became very mobile and locally shallow, with large gravel banks, making navigation increasingly difficult. It was decided to reduce the navigable channel to a minimum width of 75m by installing fields of groynes from the banks.
The rectification and regulation work created many jobs in the villages along the Rhine. In Schoenau, too, several families made their living from these Rhine trades, managed by the Rhine and Navigation Department.
IV - The canalised Rhine
Objectives, Structure and hydro-geomorphological impacts of the canalization
With regulation, navigation conditions improved greatly, except for the appearance of the Istein dam. The solution of a local bypass at Kembs, then to Strasbourg with the Grand Canal d’Alsace, emerged at the beginning of the 20th century. The industrialists of Mulhouse, led by René Koechlin, added a new objective : hydroelectric production.
The ten hydroelectric plants along the Franco-German line produce an average of 8.7 billion kWh per year, or around two-thirds of Alsace's electricity needs. In terms of navigation, the locks enable 25 million tonnes of goods to be transported by water each year in Strasbourg, compared with around 11 million tonnes in Basel.
Impact on river operations
All these changes have had a major impact on the aquatic environment, with fish populations declining sharply. In hydrological terms, the major impact of the pipeline is the loss of 130km² of floodplain. As these areas were previously used for temporary flood storage, the pipeline increased the risk of flooding by shifting it downstream.
Serious pollution of the Rhine
Pollution of the Rhine ecosystem, which led to the definitive disappearance of the salmon along the Rhine in the late 1960s, was caused by organic pollution and oil spills. Chemical pollution in the 1970s and 1980s severely degraded the life of the river.
V - The Rhine today and tomorrow
Correcting the hydrological errors of the pipeline
A Franco-German agreement was signed in 1982 to eliminate the negative hydrological effects of the canalization and, in particular, to restore flood control capacity. The aim of this agreement is to reinforce the safety of people living downstream of the canalized Rhine against the largest floods (200 years), as was the case before the canalization.
The creation of polders in France and Germany is aimed at ecological restoration, as are bank cuttings in Germany, although flood protection objectives predominate.
A wide range of regulatory tools have been put in place at international level, and actions between states are discussed and steered at the level of the International Commission for the Protection of the Rhine (ICPR).
On December 5, 2019, the French Rhine managers drew up and signed an ambitious action program: the "Rhin Vivant" plan. It is within this framework that the study to restore the forest and alluvial massif from Marckolsheim to Schoenau has been launched.
The Agence de l'Eau has launched a call for initiatives entitled "J'ai un projet pour le Rhin" (I have a project for the Rhine), to support any type of action that brings players and citizens closer to the river, in all its dimensions. All the educational panels presented here and the visitor reception area are part of this funding program.