Jura water correction
In the case of the Jura water corrections , often also referred to as Jura water corrections , the Aare was diverted from Aarberg to Lake Biel . The Hagneck Canal was built for the feed line into the lake and the Nidau-Büren Canal for the discharge back into the old Aare bed near Büren . The Broye Canal (between Lake Murten and Lake Neuchâtel ) and the Zihl Canal (between Lake Neuchâtel and Lake Biel) were built as more efficient connections between the three lakes at the edge of the Jura . With these canals, sufficient flood drains were created and the balancing effect of the three connected lakes was expanded. Even in the lower reaches of the Aare, the flood levels are lower than in previous centuries. The weir port in the Nidau-Büren Canal is used for regulation.
Subsequently, the area in the triangle between the three lakes, which had been swamped by previous floods - the Swiss Seeland in the narrower sense -, the Orbe plain west of Lake Neuchâtel and the river basin of the Aare between Aarberg and Solothurn could be drained and made usable for agriculture. Due to the lowering of Lake Neuchâtel, the former shallow water zones on the south and east banks formed the Grande Cariçaie .
The first water body correction from 1868 to 1891 turned out to be insufficient, which is why additional measures ( second Jura water body correction ) were taken in 1939 and 1962 to 1973 .
Starting point and problem solving
1: Zihl Canal
2: Broyekanal
3: Hagneck Canal
4: Nidau-Büren Canal
The small drainage canals in purple
Because of the low gradient of the Aare between Aarberg and Solothurn, this part of the Aare valley was a wide swampy and often flooded strip of land. From the 17th century onwards, the river bed increased due to sediment deposits, which increasingly impeded drainage from the low-lying, left-hand Zealand. During floods, even Aare water flowed back into Zealand. Due to the large moss that developed there, the agriculturally unusable area between Solothurn and the Seeland more than doubled by the 19th century.
A request for help to the Bernese patricians resulted in the development of a first correction proposal in 1704. After devastating floods in 1831 and 1832, the residents of all five affected cantons founded a correction committee, of which Johann Rudolf Schneider became president . After the founding of the modern federal state in 1848, correction became a national task, which accelerated its resolution.
Merely deepening and containing the Aare was not enough as a sustainable solution to the problem. The basic problem remained that the Aare, as a mountain river, carries a lot of debris, the further deposition of which in the flat course of the river from Aarberg had to be avoided in future. Lake Biel offered itself as a storage basin. The large-scale diversion of the Aare through the lake suggested lowering the water level of the three connected lakes, which was roughly the same. In this way, previously dry shoreline could be regained. In addition, the Grosse Moos, which was previously not significantly above lake level, was able to drain south into Lake Neuchâtel. The Aare diversion to the west (Hagneck Canal) and the wide and long sedimentation field north of Aarberg would have made the entire drainage to the north more difficult. To the north, only the less swampy area to the north of the future Hagneck Canal and to the left of the Alte Aare needed to be drained.
So far, the relatively small Zihl, which flows into the Aare near Büren, served as a drain from Lake Biel. The additional Aare water to be drained required a larger drainage channel: the Nidau-Büren Canal. The connections between the lakes also had to be expanded: Broye Canal between Lake Murten and Lake Neuchâtel and Zihl Canal between Lake Neuchâtel and Lake Biel.
As far as Solothurn, the old Aare from Büren had to be widened, straightened and deepened below Solothurn due to its slight gradient (removal of the so-called Emme barrier).
First Jura water correction
A federal contribution of five million francs ensured the planning and implementation of the first measures. The Grisons canton chief engineer Richard La Nicca worked - after not carried out preliminary planning of John Paul Lelewel 1834 - on behalf of the cantons of Bern , Solothurn , Friborg , Neuchâtel and Vaud , a project. It provided for the following structural measures and new systems:
- The derivation of the Aare from Aarberg into Lake Biel through the new Hagneck Canal
- Lowering of the three lakes by 2.5 m
- Drainage of the water from the Aare, Broye , Zihl and Schüss combined in Lake Biel through the new Nidau-Büren Canal
- Correction of the upper Zihl between Lake Neuchâtel and Lake Biel
- Correction of the lower Broye between Lake Murten and Lake Neuchâtel
- Adjustment work on the Büren river stretch to the Emme estuary below Solothurn.
From 1868 the Nidau-Büren Canal was the first to emerge, which was re-dug between Lake Biel near Nidau and Port and continued as a straightened and deepened Zihl. From the old Zihl estuary, a large Aare loop was cut off before the canal connected to the old Aare at Büren.
Then from 1875 the construction of the Hagneck Canal (diversion of the Aare from Aarberg into Lake Biel) followed. On August 16, 1878, the water of the Aare first flowed into Lake Biel.
In Lake Biel, St. Petersinsel and Chüngeliinsel grew together to form a larger island.
The technical means used were considerable: two steam dredgers, two steam cranes, 24 transport ships, 122 dump boxes, 60 trolleys , two small steam locomotives and four kilometers of rails.
Second correction of the Jura waters
Even after the first correction of the Jura waters, there were sometimes catastrophic floods. The problems were unfavorable conditions between the inflow and outflow of the three Jura lakes and the subsidence of the peat soils in the Grosse Moos. A second Jura water correction was planned:
- Merging of the three Jura lakes into a communicating system by widening and deepening the canals
- Increase in the drainage capacity in the Nidau-Büren Canal
- All three lake levels can be regulated by a control weir at the outflow of Lake Biel near Port
- The water level of the Aare can be regulated between Port and the mouth of the Emme near Zuchwil
- Possibility to adjust the lake level in the future to the likely increasing subsidence in the Great Moos
- a further lowering of the lake level by 1 m (St. Petersinsel became a peninsula)
With the federal decision on the approval of a contribution to the canton of Bern for the construction of a new weir system in Nidau-Port on September 20, 1935 , the Swiss parliament gave its approval for the start of the planning work.
By 1939, the Port control weir with a lock was built in the Nidau-Büren Canal .
In 1962, further work on the 2nd Jura water correction began and lasted until 1973. The following work was carried out:
- The Flumenthal power plant was built as a regulating weir
- The bed of the Aare between Büren a. A. and Flumenthal was expanded and the so-called Emmeriegel removed
- Broye, Zihl and Nidau-Büren canals as well as the Aarelauf Büren-Flumenthal were widened and deepened and the banks were expanded.
After this second correction, the Seeland became the most important vegetable growing area in Switzerland.
Discussion about 3rd Jura water correction
Some of the vegetable fields in Zealand are two meters lower than they were 30 years ago. On March 1, 2018, it was decided at the general assembly of the Pro Agricultura Seeland association to demand a third correction of the Jura waters. The initiators expect costs of one billion Swiss francs within the next thirty years.
literature
- Nast, Matthias: flooded - survived - outwitted. The history of the Jura water corrections . Edited by the Nidau Castle Museum Association. Biel 2006. ISBN 3-906140-73-3 .
- Przegon, Wojczech: Jan Pawel Lelewels general plan for the project of draining the marshland of Zealand (1834). In: Vermessung Photogrammetrie Kulturtechnik , Heft 8 (1999), pp. 432–434
- Vischer, Daniel; Feldmann, Hans-Uli: The first correction of the Jura waters, 1868–1891. In: Cartographica Helvetica , Heft 32 (2005), pp. 17–32 ( page no longer available , search in web archives: full text ).
Web links
- Documents for correction of the Jura waters at digibern (University Library Bern)
- Museum Nidau: Permanent exhibition on Jura water correction
- Canton of Bern: Jura water correction
- Swisstopo, time travel through maps from 1845 to today
Individual evidence
- ↑ a b Website of the Bern building authorities for correction of the Jura waters ( memento of the original from October 15, 2017 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.
- ^ Anne-Marie Dubler : Grosses Moos. In: Historical Lexicon of Switzerland . September 17, 2010 , accessed June 25, 2019 .
- ↑ Interview on the occasion of 150 years of correction of the Jura waters In: Der Bund from July 25, 2017
- ↑ Farmers in Seeland are losing their feet in: srf.ch , May 24, 2014, accessed on May 4, 2018.
- ↑ Resolution on the 3rd Jura water correction decided in: proagricultura.ch, March 1, 2018, accessed on May 4, 2018.
- ↑ The Seeland Canal System at the Limit: How Switzerland's Vegetable Garden should be saved In: srf.ch, November 16, 2018, accessed on November 18, 2018.
