Rhine delta (Lake Constance)

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Aerial photo from 300 m by Walter Mittelholzer (1920)

The Rhine delta of Lake Constance is the river delta on the southeastern shore of Lake Constance, which the Rhine (also called the Alpine Rhine here ) formed in a former lake area. Most of it is in the Austrian state of Vorarlberg , with smaller areas in the Swiss canton of St. Gallen . The two peninsulas in the lake are called Rheinspitz (west) and Rohrspitz (east).

location

Notice board with general plan
The old Rhine at Höchst
Flocks of water birds in the Fußacher Bay
Rohrspitz, part of the Rhine delta
The Rheinspitz in Gaißau has been grazed for centuries.
On the Rohrspitz peninsula

The delta of the Alpine Rhine forms a common delta area with the deltas of Dornbirner Ach and Bregenz Ach that adjoin to the east . This delta area extends over the entire valley area (in the bank area from Staad in the west to Bregenz in the east). In the north, the current shores of Lake Constance naturally form the boundary, provided that one ignores the delta that continues below the surface of the lake. The limit to the south depends on the determination of the course of the shores of Lake Constance after the Rhine glacier melted and should be at least a few kilometers. The beginning of the 20th century in the Rhine breakthrough between Lustenau and Fußach is not an original delta arm and runs in its lower section through the area of ​​the historic Dornbirner-Ach delta. Nevertheless, since then the main delta has been formed at the mouth of the Rhine gorge between Fußach and Hard , and no longer at the former main mouth of what is now the Old Rhine . Like the Rhine near Lustenau, the Old Rhine nestles closely against the western slope of the Rhine Valley and forms the state border between Austria and Switzerland. The alluvial forest on the Austrian side of the Rheinspitz on the old Rhine is known as Rheinholz .

development

After the retreat of the Rhine glacier after the last glacial period , Lake Constance was formed, which originally extended further south in the area of ​​the Rhine valley . At the same time, the delta began to form at the confluence of the Alpine Rhine. This process continues to this day and is part of a process that would end with the complete silting of Lake Constance in several thousand years .

With the construction of the polder dam (1956–1963), the lowering of the water level by the pumping stations, and the clearing of alluvial and swamp forests, areas close to the lake could be used more intensively for agriculture.

History of the protected areas in the Rhine delta

The Rhine delta is the largest wetland protected area on Lake Constance and extends from the mouth of the Old Rhine via the mouth of the New Rhine to the Dornbirner Ach in Hard. Around 2000 hectares of shallow water, reed beds, wet meadows and alluvial forests are protected. It is also an important breeding and resting area for birds throughout Europe. To date, 330 species of birds have been observed. On the Austrian as well as the Swiss side, there is a nature reserve, in Vorarlberg there is also a Natura 2000 area ( fauna, flora, habitat and bird protection ), a Ramsar area .

The Rheinau nature reserve

Extensively agriculturally used areas in the Rhine delta. In the foreground a group of foraging Big curlews
Rhine delta - aquatic landscape to the left of the Rhine dam

Even before the war, the lowest Rhine floodplains were under severe pressure, in Vorarlberg with the industrial centers Höchst and Hard, in St. Gallen with the construction of the Dornier works around 1920 and the construction of the Altenrhein airfield .

Günther Schlesinger (1886–1945), who is now considered the “father of Austrian nature conservation” and is the permanent representative of the Austrian state agencies for nature conservation, described Vorarlberg's views on nature and hunting law as “backward” in 1936: all animals considered harmful to fishing or hunting faced unrestrained and ruthless persecution. The list created in this way was continuously expanded to include more “robbers”, and by the middle of the 20th century, wolves, lynxes, wild cats, brown bears and otters were completely exterminated in Vorarlberg.

In 1939 Friedrich Lürzer, forester from Bregenz, submitted an application for the application of the Reich Nature Conservation Act on an area of ​​750 hectares on the shores of Lake Constance between the Old and New Rhine estuaries and recommended urgently to designate a protected area in the Rhine delta, "one of the rarest in terms of landscape and fauna [Areas] Central Europe ”was. On August 21, 1942, with the ordinance on the temporary safeguarding of the Rheinau nature reserve, the Rhine delta on the lake side of the polder dam, which was already planned at the time, including a one-kilometer-wide water strip and the Rheinholz, was declared the first Vorarlberg protected area.

In addition, the lakeshore protection ordinance, which should protect all lakes in Vorarlberg and Tyrol from further construction and privatization, stipulated:
“Within this area, it is forbidden to change the landscape, build new drainage systems, bathing huts and paths, agricultural use including pipe cutting and the To exercise pasture to a greater extent than the previous one and to carry out logging (except in Rheinholz). "

After the Second World War, there were lively debates about the adoption of the Lake Shore Protection Ordinance in Vorarlberg state law. The District Authority of Bregenz as the lower nature conservation authority, and the Lake Constance communities of Bregenz, Lochau and Hörbranz advocated retention. Hard, Höchst, Fußach and Gaißau opposed this because they feared economic disadvantages and interference with property relations. In 1949 the ordinance was finally announced again in the official gazette No. 33 for the state of Vorarlberg and all municipalities of Vorarlberg were asked to act as building authorities to ensure compliance with the lake shore protection regulations.

From the beginning of the 1950s, requests for special permits for the construction of bathing huts, weekend cottages, camping sites, fishermen's huts and tool sheds increased on Lake Constance. Exemptions from the Lake Shore Protection Ordinance were also required for the construction of ports, storage areas and the removal of gravel or sand. In 1957, the Vorarlberg state government finally decided not to grant any more exceptional permits in the Rhine delta.

The polder dam

Construction of the polder dam, Fußach 1959

With the construction of the polder dam (1956–1963), the lowering of the water level by the pumping stations and the clearing of alluvial and swamp forests, areas close to the lake could be used more intensively for agriculture. Proponents of the dike saw it as "the conquest of a considerable granary", while conservationists soon pointed out the negative consequences of the changed groundwater balance and demanded that part of the wet meadows be placed under nature protection in order to preserve the diversity of plants and animals.

In 1963, the journal Schweizer Naturschutz reported under the title Das Rheindelta vor dem Untergang that “the most bird-rich area in Central Europe has already been partially destroyed and will soon be doomed if it is not possible to protect at least parts of it.” A year later, the WWF decides -International to include the Rhine delta as a project with particular urgency in its program of activities.

The Austrian Institute for Nature Conservation and Landscape Management was also critical in a letter from 1971: “... according to the consensus of domestic and foreign conservation experts, the Vorarlberg Rhine Delta is one of the most valuable and at the same time most worthy of protection areas in Europe. The Vorarlberg state government should therefore stop work on lowering the groundwater level immediately and do everything in its power to achieve an effective protection of the area. "

The Vorarlberg nature reserve Rhine Delta

In 1976, on the basis of the draft prepared by the Vorarlberg Agency for Nature Conservation on the basis of the nature conservation ordinances in Tyrol and Lower Austria, the state of Vorarlberg issued a protected area ordinance for a nature reserve comprising 1,972 hectares of shallow water, reeds, wet meadows and alluvial forests as well as around 250 hectares of litter meadows in Fußach and at the top of the land Polder dam included. Until the early 1990s, however, the ordinance for the areas on the landside of the polder dam was limited to five years each. The demand to put all areas under permanent protection, as well as to integrate the valuable flat moors of the Gaißauer Ried and the Speichenwiesen Höchst into the nature reserve, failed due to the resistance of the communities. Likewise, a landscape protection area requested by Broggi in 1981 as a buffer zone for the nature reserve was not implemented. In 1992, for the first time, an ordinance was issued for a period of ten instead of five years, which has been in force since 2002.

The Altenrhein nature reserve in St. Gallen

Between the village of Altenrhein and the mouth of the Old Rhine lies the small nature reserve Altenrhein , with an area of ​​28 hectares.

Here, too, until the 1975 reed meadows were leveled and used as building ground. Additional pressure arose from the Swiss Autobahn 1 , which is a few hundred meters away from the lake shore as far as the Old Rhine. A trend-setting ruling by the Federal Supreme Court in Lausanne puts every reason under lake protection.

International agreements

Since December 16, 1982, the Rhine delta has been under the protection of the Ramsar Convention for Wetlands (Ramsar area Rheindelta  No. 275 , 2065 hectares).

In 2003, the Rhine delta was to protect Europe's most valuable species and habitats and the conservation of biological diversity ( biodiversity ) in the list of Natura 2000 sites listed in accordance with the Birds, as well as the EU's Habitats Directive ( AT3402000 ), it comprises 2,066 Hectares.

Rhine dam and mouth of the Rhine

The mouth of the Rhine near Hard. View from the Bödelestrasse

The mouth of the Alpine Rhine was relocated from the shallow water area seaward to the steep slope of the lake shore, the dump. For this purpose, an S-shaped dam, around 5 kilometers long, has been built since the 1970s, which guides the sediment masses into the deeper areas of Lake Constance.

literature

  • Maria Aschauer (research and editing); Markus Grabher, Ingrid Loacker (Red.): History of nature conservation in Vorarlberg. A consideration from an ecological point of view . Report prepared on behalf of the Vorarlberg Nature Conservation Council. Ed .: UMG Umweltbüro Grabher. December 7, 2007, 9. History of the Vorarlberg protected areas using five examples 9.1. Rhine delta , S. 85 ff . ( pdf , naturschutzrat.at ; website , umg.at - pdf p. 1 ff). Maria Aschauer, Markus Grabher: The development of the Rhine Delta nature reserve. A historical summary . In: UMG reports . No.
     3 , May 2010 ( pdf , rheindelta.com - more recent monograph).
  • Josef Zoller: The Altenrhein nature reserve in the Swiss Rhine delta , in: Writings of the Association for the History of Lake Constance and its Surroundings , 126th year 2008, pp. 231–248 ( digitized version ; further digitized version as PDF )

Web links

Commons : Rhine Delta  - collection of images, videos and audio files

Individual evidence

  1. ↑ Rhine Delta nature reserve. Retrieved June 17, 2019 .
  2. ↑ Ordinance on the temporary safeguarding of the Rheinau nature reserve. Ordinance and Official Gazette of the Reichsgau Tyrol and Vorarlberg No. 122/1942.
  3. ↑ a b c Ordinance on the Rhine Delta nature reserve in Fußach, Gaißau, Hard, Höchst and in Lake Constance LGBl. 13/1976, 67/1976 11/1978, 51/1981, 50/1986, 55/1988, 44/1991, 68/1991, 57/1992, 63/1994, 31/1995, 40/1995, 59/2000 , 64/2002.
  4. ^ Josef Zoller: The Altenrhein nature reserve . AGBU eV - Topic of the month. January 2005 ( bodensee-ufer.de [PDF]).
  5. ↑ a b lit. Zoller: The Altenrhein nature reserve . S. 232 f. (pdf p. 2 f.) (with a map 1888 and the protected area boundaries).
  6. ↑ Rhine delta, Lake Constance. In: UMWELTnet> Nature & Species Protection> Wetlands (Ramsar)> Ramsar areas. Federal Ministry of Agriculture, Forestry, Environment and Water Management (BMLFUW), accessed on May 3, 2011 .
  7. ↑ Natura 2000 area Rhine delta. In: vorarlberg.at · Nature and environmental protection · Natura 2000. Land Vorarlberg, accessed on November 13, 2012 .
  8. ↑ Marion Rapp: 111 natural treasures around Lake Constance that you have to see. Emons Verlag GmbH, 2015, ISBN 978-3-95451-619-3 . Der Rheindamm , pp. 72–73.

Coordinates: 47 ° 29 ′ 0 "  N , 9 ° 38 ′ 0"  E ; CH1903:  765,397  /  261487