Grand Canal d'Alsace

Side of the river channel is the commonly held German name of the French Grand Canal d'Alsace (French for literally large channel of Alsace, otherwise Rhine channel): a ship canal between Huningue (F) or Weil am Rhein- Märkt (D) and Breisach (D). The border between Germany and France running between Märkt and Breisach in the thalweg of the east of the canal running parallel to the Rhine, often referred to as residual or Altrhein.

History

The Treaty of Versailles France received in 1919 not only the Rhine frontier, but in Article 358 and the right to any discharge of Rhine water as well as the use of water power of the river Rhine in the border section. The half of the electricity produced Germany should be credited. Taking advantage of this clause France began, west of the French once again part of the Rhine between Saint- Louis and Lauterbourg to schedule a channel and to realize that not only served the shipping industry, but also the generation of electricity. In order to maximize the energy gain should virtually all the water of the Rhine to the mean water ( 1,400 m³ / s) run through the channel and the planned him French power plants. In the limiting flow should remain only a slight residual amount of water. 1928 started ( barrage Kembs with weir at Märkt ) in Basel with the construction of the canal (Rhine side channel ). With the occupation of France in World War II, the work was interrupted.

In the fifties, the construction was resumed and continued until after Breisach. In negotiations with France, the German government under Adenauer reached that France renounced for the section of the river north of Breisach in favor of a " loop solution " to the original channel design: The future phase of construction, the water should be led only for the length of a barrage on French territory and again in the Rhine are returned. The shipping route of the Rhine has been provided in the section to Strasbourg with several leading through France River " loops ". With the ongoing construction of the canal in its original conception, the groundwater level in German (and equally in French ) hinterland would further adversely changed and it would also be cut off from Breisach by a scheduled boat traffic, the German port facilities. The political price for the agreement by France to sling solution and thus to refrain from an actual channel was the German approval of the Moselle canalization and - due to higher production costs of the now realized loop solution - the renunciation of the hälftige remuneration of electricity sales by France.

The construction of the Rhine side channel also Isteiner thresholds that pose a threat to shipping to Basel, were bypassed.

At the crossing of the Rhine-Rhone canal in Kembs - Niffer a control tower for the transport lock and a customs house were built in 1959 by the Swiss-French architect Le Corbusier. The roof of the customs house is a hyperbolic paraboloid: a Hyparschale, at the lowest point of the rain water is collected and drained. The tower consists of two diagonally placed one above the other dice. An external staircase leads to a glassed-in platform that enables the view in both channel directions.

Hydropower

In the course of the channel, there are four barrages with river hydropower plants, which include all the French energy company Electricite de France (EDF):

• Kembs power plant, completed in 1932, relicensing 2011
• Power plant Ottmar home, completed in 1952
• Fessenheim power plant, completed in 1956,
• Power plant Vogelgrun, completion 1959

Ecology

Groundwater level

The water table has been lowered so far that both the German and the French side an agricultural use of the floodplain was impossible by the construction of the canal; For this reason, the so-called loop solution was reacted with four loops for improved navigation and energy between Breisach and Strasbourg instead of a solid channel.

Flood

With the construction of ten dams in the Upper Rhine was the water outflow of the Rhine, especially at high water, accelerated. In the 19th century, the Rhine was able to extend still strongly meandering in its floodplain. The weirs at the power plants are used for removal of high water, and preservation of the water storage level for the power plants to produce energy as well as the water level for navigation in the channel. Although the faster water drainage eliminates the risk of flooding in the channel section of the Rhine, but promotes the coincidence of flood crests of the Rhine to those of the tributaries Neckar, Main and Mosel and thus causes a tightening of the flood hazard in the Middle Rhine and Lower Rhine. At high tide, no maximum energy utilization is more due to the lower height of fall to the barrages at power plants possible: From a flow rate of about 3,300 cubic meters per second with a rising trend in Basel and is when the level Maxau reached or exceeded an outflow of 4,200 m³ / s, the so-called special operation of the Rheinkraftwerke is performed. The Rheinkraftwerke throttle the flow to a minimum of 200 m³ / s and the rest of the water is passed through the weirs in the original Rhine bed (max. 4500 m³ / s). This special mode of Rheinkraftwerke was decided as part of the flood control measures of the Integrated Rhine Programme (IRP ). The retention volume is about 45 million m³ /.

Minimum flow Altrhein

In January 2011, the years between conservationists controversial, France and Switzerland relicensing of the hydropower plant Kembs stepped up in 2035 in force: here, a substantial increase in the minimum flow for the old Rhine has been agreed.

Flume Altrhein, gravel bedload, Aqua fauna

In a feasibility study to Redynamisierung the rest of the Rhine ( Interreg - project 2010-2012 ) was examined by the addition of approximately 25 000 m³ of gravel at Kleinkems whether the sediment dynamics of the Old Rhine could be improved by: this should improve, among other things, the conditions for gravel -spawning fish species.

Loop solution

The waterway runs alternately on the Rhine and in the channel, the snares. Are present at the loops barrages with power plants and locks. In Altrhein two cultural weirs in Breisach and Kehl were built that ensure there is always enough water in the river bed is installed and fixed thresholds, so that a further decline in the groundwater level is prevented. The lowering of the groundwater level could only be reduced by the loop solution. As a problem, the vertical erosion of the river was due to its reduction and the concomitant stronger gradient exist. The construction of additional dams, barrage Gambsheim (1974) and Iffezheim (1977 ), was used in addition to the energy of avoiding further erosion. Below Iffezheim the sole means of regular sediment erosion is prevented by the addition of Waterways and Shipping Administration or regulated. If this can not be adhered to, would Germany and France discuss whether further dam is being built in the area Lauterburg - Neuburgweier. The cost would be approximately $ 1-2 billion euros.

Coordinates

• Source of the canal: 47 ° 36 ' 59 " N, 7 ° 34' 18" O47.6163888888897.5716666666667Koordinaten: 47 ° 36 ' 59 " N, 7 ° 34' 18" O
• Endpoint of the channel: 48 ° 2 '0 "N, 7 ° 34 ' 5" O48.0333333333337.5680555555556