Bachgraben (Allschwil)
The Bachgraben is a former tributary of the Rhine near Basel and today gives its name to an industrial, sports and leisure area in the suburb of Allschwil in the canton of Basel-Landschaft . In Allschwil, the river specifically bears the official name of Dorfbach (locally also Allschwilerbach or Allschwilergraben ).
River system
The creek ditch arises from the confluence of the Mühlebach and the Lützelbach around 100 meters south of the Allschwil village square:
- The Lützelbach (also Lützelbächli) rises in the westernmost part of the Allschwil Forest on the border with Schönenbuch at approx. 375 m above sea level. M. and flows through the hamlet of Ziegelhof for around 3 kilometers
- The Mühlebach rises from two stream sources in the Leymener Eichwald, briefly crosses Switzerland at Benkenspitz as Neuwilbächli and then turns as Neuwillerbach northeast to Neuwiller (France). From the re-entry into Swiss territory, the stream bears the official dialect name Mülibach .
The field ditch was an artificially created secondary canal between the confluence of the two source streams and the former confluence with the Dorenbach. This is guaranteed since 1396 at the earliest. After an unlawful backfill by citizens of Allschwil in 1771, the city of Basel forced the court to reopen the field ditch. After the creek ditch was briefly used as a trench during the Second World War , the field ditch was closed in 1940.
history
Until the 17th century, the Dorfbach near Neuallschwil was a tributary of the Dorenbach ; Before the partial canal diversion, this flowed northwards from 1428 approximately along today's cantonal border and crossed the Friedmatt to Bourgfelden in the urban area , where it branched off to the east and flowed along the state border into the Rhine.
The name bach graben is first documented in a manuscript from the Kleinbasel Carthusian monastery in 1451 . The previously natural and constantly changing river bed was dammed after 1575 at the instigation of the Basel prince-bishop Jakob Christoph Blarer von Wartensee . With the complete diversion of the Dorenbach from 1677, the water volume in the old Dorenbach river bed was reduced to such an extent that the creek ditch already seeped into the soil of the lower terrace at Lysbüchel ( St. Johann quarter ); this lower section of the river, which from then on only rarely had water, was popularly known as the Bettelgraben .
In the 19th century at the latest, the course of the river was overturned by the construction of the Strasbourg – Basel railway line in the Lysbüchel area. As a result of a flood on September 9, 1945, the creek ditch was introduced into a provisional supply line of the municipal sewer system created in 1934 and thus disappeared underground before the canton border. 1981 to 1983 a separate discharge was built directly into the Rhine, in the immediate vicinity of the state border, where the old Dorenbach had its natural mouth. The street names Bachgraben-Promenade ( Iselin-Quartier ) and Am Bachgraben (near Lysbüchel) are reminiscent of the earlier course of the river. In Allschwil, the Dorfbach continued to flow openly until it overturned to the present area in 1970.
From 1960 to 1962, the Bachgraben garden pool was built on both sides of the canton border.
In the past there have been regular floods in the still open creek ditch on Allschwiler Boden; Most recently, on June 4, 2018, a thunderstorm-related flooding of the Lützelbach caused considerable damage. Two major floods in 1995 and 1996 were followed by a flood protection project that reduced the risk of flooding in the Mühlebach. In March 2019, protective work was also completed on the Lützelbach.
literature
- Hansjörg Huck: The western Allschwiler Bachgraben (Dorfbach) and Oestlicher Bachgraben. Feldgraben or Feldbachgraben. In: Before the then Steinin-Crüz-Thor. Basel 2006.
- André Salvisberg : The Basel street names. Christoph Merian Verlag, Basel 1999.