Water correction

The water correction (more rarely also: water correction) is a term from hydraulic engineering and water management , with the redesign of rivers and lakes for the purpose of flood protection, the use of the water for shipping or other commercial purposes and usually also land reclamation and the agricultural improvement of the adjacent floodplain are described. The term has been common, especially in the 19th century, for the major changes in the Central European river systems such as the Rhine and Danube. In today's linguistic usage it is only used as a technical term in Switzerland . In Germany, the term water development is used in the same sense .

Legal regulations in Switzerland

Article 37 (construction and correction of rivers) of the Swiss Waters Protection Act stipulates: “Rivers may only be blocked or corrected if: a) the protection of people or significant property requires it; b) it is necessary to make it navigable or to use hydropower in the public interest; b ^bis ) it is necessary for the construction of a landfill that can only be built at the intended location and on which only unpolluted excavated material, overburden and excavated material is deposited; c) as a result, the condition of an already built or corrected body of water can be improved within the meaning of this Act. "Article 3 (measures) of the Federal Act on Hydraulic Engineering stipulates:" (1) The cantons ensure flood protection primarily by maintaining the bodies of water and through spatial planning measures. (2) If this is not sufficient, measures such as barriers, containment, corrections, bed load and flood retention systems as well as all other precautions that prevent soil movement must be taken. "

The big flow corrections

The rivers of Central Europe, including Switzerland, were mostly almost naturally flowing wild rivers until the 19th century . Within its floodplain, the river frequently shifted its course, relocating all sediments. The floodplains were also flooded by regular floods. They were therefore avoided as settlement land and could only be used agriculturally as pastureland. The growing population and the associated scarcity of land meant that, despite the dangers, more and more people settled in the floodplains. At the same time, however, the floods became stronger and threatened the previously flood-free settlements on the edge of the valley. This is attributed to a combination of two factors: the increasing deforestation of the highlands, which increased the direct runoff, and an increase in precipitation. As a special feature of the mountainous countries, the smaller alpine rivers in particular carried huge masses of debris with them during floods , which sometimes rivers such as the Rhine could turn into lakes. After a series of catastrophic floods with enormous damage, plans were drawn up in more and more regions to “correct” the rivers, ie to convert them into a condition that is favorable for people. In the earlier days of the Old Confederation , the huge investments required for this could simply not be raised for economic and political reasons. The only major exception and forerunner of the later measures was the kander correction (1711 to 1714) by the municipality of Bern. The corrections were seen by contemporaries as tremendous acts with a high symbolic significance, in which humans conquer hostile nature through internal colonization .

Around the same time in Germany, initially in Baden, the plans for the correction of the Rhine were developed, which inspired the Swiss for their own projects. From 1807 to 1808, the chief engineer Johann Gottfried Tulla also worked out the plans for the Linth correction (1807 to 1816), the first national measure of the new Confederation. A much larger work was the first Jura water correction (1868 to 1891), in which the Aare in the Central Plateau in particular was regulated in the discharge. Not only was the course of the river straightened and laid between dams, but also an extensive moor, the Großer Moos, which is now an important vegetable-growing area. Almost at the same time, the Rhone correction in Valais was tackled from 1863 to 1893 . From 1892 onwards the Rhine was corrected between the Landquart estuary and Lake Constance. The Rhine in the Diepoldsauer breakthrough was relocated to a new bed and its course was shortened by 10 kilometers.

These large corrections and the numerous smaller subsequent corrections, such as the corrections of the Ticino in the Magadino plain , the Gürbe , the Töss and the Emme, have resulted in Switzerland having a higher proportion of built, regulated and water-managed bodies of water in relation to the usable land area most other European states owns.

In Germany, after the correction of the Rhine, other major hydraulic engineering projects in the 19th century were still called this, for example the Weser correction from 1887 to 1895, during which the Weser as far as Bremen was made navigable for ocean-going ships. For the following, mostly smaller measures of the 20th century, the term was not used.

Procedure

The construction of river groynes in straightened rivers deepens the water and promotes navigability

Corrections in alluvial plains consist in particular of the amelioration of the soil through drainage in order to drain it, to dry it out and to make it arable. In addition, rivers are straightened and canalized in order to achieve higher flow speeds and transport capacities for bed load . Diversions of the rivers into lakes gave the bed load natural storage basins and led to natural compensation basins during floods .

Individual evidence

↑ Federal Act on the Protection of Waters (Water Protection Act, GSchG) of January 24, 1991 (as of January 1, 2017)
↑ Federal Act on Hydraulic Engineering of June 21, 1991 (as of January 1, 2011)
^ Eduard Gerber: The river meadows in the Swiss cultural landscape. Works from the Geographical Institute of the Swiss Federal Institute of Technology Zurich, 43. Zurich 1967, 26 pages.
^ Daniel Vischer: Swiss river corrections in the 18th and 19th centuries. Announcements from the Research Institute for Hydraulic Engineering, Hydrology and Glaciology at the Swiss Federal Institute of Technology in Zurich 84. Zurich, 1986. 77 pages.
↑ Daniel Vischer: The history of flood protection in Switzerland. From the beginning to the 19th century. Reports of the BWG, Series Wasser 5. Bern, 2003. 208 pages.
↑ Horst Johannes Tümmers: The Rhine: a European river and its history. CHBeck Verlag 1999. 479 pages. ISBN 978-3-406-44823-2 . on pages 59–63.
↑ Peter Rey, Edwin Müller: EU water framework directive and Swiss water and water protection legislation: a comparison. Expert opinion on behalf of the Federal Office for the Environment (FOEN), Bern 2007.

Web links

Daniel Vischer: Water Correction. In: Historical Lexicon of Switzerland .

[1] Federal Act on the Protection of Waters (Water Protection Act, GSchG) of January 24, 1991 (as of January 1, 2017)

[2] Federal Act on Hydraulic Engineering of June 21, 1991 (as of January 1, 2011)

[3] Eduard Gerber: The river meadows in the Swiss cultural landscape. Works from the Geographical Institute of the Swiss Federal Institute of Technology Zurich, 43. Zurich 1967, 26 pages.

[4] Daniel Vischer: Swiss river corrections in the 18th and 19th centuries. Announcements from the Research Institute for Hydraulic Engineering, Hydrology and Glaciology at the Swiss Federal Institute of Technology in Zurich 84. Zurich, 1986. 77 pages.

[5] Daniel Vischer: The history of flood protection in Switzerland. From the beginning to the 19th century. Reports of the BWG, Series Wasser 5. Bern, 2003. 208 pages.

[6] Horst Johannes Tümmers: The Rhine: a European river and its history. CHBeck Verlag 1999. 479 pages. ISBN 978-3-406-44823-2 . on pages 59–63.

[7] Peter Rey, Edwin Müller: EU water framework directive and Swiss water and water protection legislation: a comparison. Expert opinion on behalf of the Federal Office for the Environment (FOEN), Bern 2007.