Jura water correction

In the Jura waters corrections, often referred to as Jura water correction, the river Aare from Aarberg was diverted into Lake Biel. For the supply line into the lake of Hagneckkanal and for the derivation was built back into the old Aare- bed at the Nidau- Buren Buren channel. As powerful connections between the three peripheral Jura lakes of Broye canal were built ( between Murten and Neuchâtel ) and the Zihlkanal ( between Neuchâtel and Biel ). With these channels adequate flood flows have been created and extended the balancing effect of the three contiguous lakes. The Aare achieved in the lower reaches lower flood levels than in previous centuries. To regulate the military port in Nidau- Buren - channel is used.

Then could the marshy area by previous floods in the triangle between the three lakes - the Swiss Seeland in the narrow sense - be the Orbeebene west of Lake Neuchâtel and the flow of the Aare between Aarberg and Solothurn drained and made ​​suitable for agriculture. The lowering of Lake Neuchâtel formed from the former area of ​​shallow water on the south and east bank of the Grande Caricaie.

The first Gewässerkorrektion 1868-1891 proved to be insufficient, which is why in 1939 and 1962 to 1973, additional measures (second Jura water correction ) were performed.

Background and problem solving

Due to the low gradient of the river Aare between Aarberg and Solothurn this part of the Aare valley was a broad versumpfter and often flooded land strip. From the 17th century the river bed increased by sediment deposition, so that the drainage from the deep left side Zealand was increasingly hindered. At high tide, even Aarewasser flowed back into Zealand. Through the resulting there Grosse Moos the agriculturally usable area between Solothurn and the Seeland enlarged as far as the 19th century to more than double.

A request for assistance to the Bernese patrician 1704 caused the development of a first Korrektionsvorschlags. After devastating floods in 1831 and 1832, the residents established from all five cantons concerned a Korrektionskomitee, whose president Johann Rudolf Schneider. After 1848 saw the foundation of the modern state of the correction was to statewide task, what their solution accelerated.

To deepen the Aare and contain only was not sufficient as a sustainable solution. The basic problem was that the Aare as a mountain river carries a lot of sediment, which further deposition in shallow river from Aarberg was to be avoided in the future. As deposition basin of Lake Biel offered. The large-scale diversion of the Aare by the lake suggested to lower the high water level approximately equal to the three connected lakes. In this way, once dry shoreline could be recovered. In addition, the drainage of the date is not significantly higher than the Seespiegeln Great Marsh could be in the Lake of Neuchâtel to the south. The Aare redirection to the west ( Hagneckkanal ) and the wide and long deposition field north of Aarberg have hampered the entire drainage to the north. To the north, just needed the less marshy, north of the future Hagneck and left the old Aare -lying area to be drained.

So far, the near Buren opening into the Aare relatively small Zihl served as the outflow from Lake Biel. The addition dissipated Aare water required a larger trough: Nidau- Buren - channel. To extend were the connections between the lakes: Broye Canal between Murten and Neuchâtel and Zihlkanal between Neuchâtel and Biel.

Until the old Aare Solothurn from Buren was to widen because of their low gradient, to straighten and deepen below Solothurn (elimination of the so-called Emme - bar ).

1 Jura water correction

A contribution of the State of five million francs secured the planning and implementation of the first measures. The Grisons canton chief engineer Richard La Nicca worked - after not carried out preliminary planning of Jan Pawel Lelewel 1834 - on behalf of the Bern, Solothurn, Fribourg, Neuchâtel and Vaud, select a project. It looked following structural measures and Reinvestment ago:

• The derivation of the Aare from Aarberg into Lake Biel by the new Hagneckkanal
• Reduction of the three lakes around 2.5 m
• Derivative of the meeting within the Biel water of the Aare, Broye, Zihl and bowl by the new Nidau- Buren - channel
• Correction of upper Zihl between Neuchâtel and Bienne
• Correction of lower Broye between Murten and Neuchâtel
• Adaptation work on the stretch of river Buren to Emme estuary below Solothurn.

As from 1868, was the first of the Nidau- Buren - channel that was between Lake Biel at Nidau ​​and port dug new and continued as a straightened and deepened Zihl. From the old Zihl mouth a large Aare loop yet was cut off before the channel joined in Bueren an old Aare.

Then followed in 1875 the construction of the Hagneck ( redirection of Aarberg Aare into Lake Biel ). On August 16, 1878, the Aare water flowed for the first time in Lake Biel.

In Biel St. Peter's Island and the Chüngeliinsel grew together to form a larger island.

The technical means used were remarkable: two steam excavators, two steam cranes, 24 transport ships, 122 Kippkisten, 60 trolley, two small steam engines and four kilometers of track.

2 Jura water correction

Even after the first Jura water correction, it still came to sometimes catastrophic flooding. The problems were unfavorable ratios between the inflow and outflow of the three Jura lakes and subsidence of peat soils in the Great Marsh. A second Jura water correction was planned:

• Merger of the three lakes to a communicating system by broadening and deepening of channels
• Increasing the drain assets in Nidau- Buren - channel
• Regulation of all three Seeniveaus by a Regulierwehr at the outflow of Lake Biel at Port
• Controllability of the water level of the river Aare between Port and the Emmemündung at Zuchwil
• Possibility for future adjustment of the lake level to the expected increasing reduction of soils in the Great Marsh
• A further lowering of the lake level by 1 m (St. Peter's Island was a peninsula )

The federal decision to grant a contribution to the Canton of Bern for the creation of a new weir in Nidau ​​port of 20 September 1935, the Swiss Parliament gave its approval to begin the planning work.

By 1939, then emerged in Nidau- Buren - channel Regulierwehr the port with a ship lock.

1962 began the further work of the second Jura water correction, which lasted until 1973. The following work was performed:

• The power plant Flumenthal was created as Regulierwehr
• The bed of the river Aare between Buren A. and Flumenthal was extended and the so-called Emmeriegel away
• Broye, Zihl and Nidau ​​-Büren canal and river Aare Buren - Flumenthal were widened, deepened and expanded the bank.

After this second correction is the Seeland became the main vegetable -growing region of Switzerland.