Orisbach

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Orisbach
Orisbach in Liestal.jpg
Data
Water code CH : 5
location Districts of Liestal ( BL ) and Dorneck ( SO ), Switzerland
River system Rhine
Drain over Ergolz  → Rhine  → North Sea
origin The confluence of the Bürener Dorfbach and Ruestelbach near Büren
47 ° 27 ′ 1 ″  N , 7 ° 41 ′ 10 ″  E
Source height approx.  412  m above sea level M.
muzzle in Liestal in Ergolz Coordinates: 47 ° 29 '14 "  N , 7 ° 44' 9"  E ; CH1903:  622 395  /  259 662 47 ° 29 '14 "  N , 7 ° 44' 9"  O
Mouth height approx.  305  m above sea level M.
Height difference approx. 107 m
Bottom slope approx. 12 ‰
length 9 km
Catchment area 20.8 km²
Discharge at the Liestal
A Eo gauge : 20.8 km²
NNQ
MNQ 1981–2018
MQ 1981–2018
Mq 1981–2018
MHQ 1981–2018
HHQ (2016)
0 l / s
120 l / s
280 l / s
13.5 l / (s km²)
520 l / s
17.3 m³ / s
Small towns Liestal

The Orisbach is a nine kilometer long stream in the cantons of Solothurn and Basel-Landschaft . It rises in the border area between the two cantons in the Tabular Jura on the edge of the Gempen plateau and flows into the Ergolz in Liestal . The Orisbach shapes the Oristal, which it also gave its name to.

Stream course and history

Spring streams

The Orisbach has two source rivers, the Dorfbach von Büren and the Ruestelbach, which in turn consists of two source streams in the source area for the first 300 meters. While the Bürener Dorfbach in the center of Büren at 432 m above sea level. M. rises, the sources of the Ruestelbach lie in the Solothurn-Baselbieter border area southeast of Büren resp. southwest of Lupsingen (BL). The eastern, somewhat longer source stream of the Ruestelbach rises south of the Hagenmatt on Solothurn soil at 460 m above sea level. M., the western source brook about 500 meters west of it on Baselbieter soil at Hof Öschtel at 470 m above sea level. The two source streams converge at Hof Rotengrund directly on the border between the two cantons.

In the valley floor one kilometer east of Büren, the 1 km long Bürener Dorfbach and the two kilometer long Oestelbach flow together on Solothurn soil. From this point of confluence, the body of water is officially called Orisbach.

Grenzbach

A few hundred meters east of the confluence, on the border between Büren and St. Pantaleon , the Oristal narrows. From this point to Neunuglar shortly before Liestal, the Orisbach forms the border between the cantons of Solothurn and Baselland in the middle of its creek bed. Overall it is 2/3 of its length Grenzbach. In the further course the Orisbach meanders through the rather narrow and largely uninhabited Oristal. In the course of time the brook has increased to an average height of 390 m above sea level. M. dug through the Jurassic rock. On the left bank heights of the Table Jura are the localities and St. Pantaleon and Nuglar , on the right bank also the Baselbiet communities Lupsingen and Seltisberg. These places are about 100 meters above the valley floor. The main road from Liestal via Büren to Seewen also follows the valley floor .

Course and history in Liestal

Near Neunuglar, a small hamlet of Nuglar on Talstrasse, the stream becomes a pure Baselbieter body of water. Half a kilometer downstream, the Orisbach flows through the Orishof, a rainbow trout farm with several artificial breeding tanks fed by the Orisbach. Immediately afterwards it flows through an industrial district in the city of Liestal. At the end of the 1980s, the stream was moved in the northern part from the center of the industrial area to the eastern edge of the valley floor.

Immediately afterwards the brook pours over a small artificial waterfall. Before the fall, water is artificially taken from the stream through the Schwieribächli. While the Schwieribächli is only used for decorative purposes these days and only leads a few hundred meters, in the 19th century the Schwieribächli led to the old town of Liestal, where the water of the Orisbach was used industrially (including the drive of mills, which is reminiscent of the Stadtmühle inn still at this time). From 1877 the water was also used for drinking water supply, which in 1890 led to a typhoid epidemic with 21 deaths.

The Orisbach itself meanders through the Schwieri residential area and passes under the Basel - Olten railway line immediately east of the train station. Immediately afterwards, the stream flows under the post office car park and flows through the avenue of Liestal. This level between the train station and the old town, both of which are elevated above it, consisted for centuries of swamp and a lake, the Oris lake. This area was drained as early as 1799. Even today, the Hinterseeweglein and the Seestrasse are a reminder of the original events. After the avenue, the Orisbach flows northwards west of the old town and finally pours out at 313 m above sea level. M. at the Konrad-Peter-Areal in the Ergolz .

facts and figures

Hydrology

The Orisbach has a length of almost seven kilometers (9 kilometers with source streams) and a catchment area of ​​20.8 km². The long-term mean annual runoff is 0.3 cubic meters per second. However, the water level is heavily dependent on the weather and the season. In the very dry summer of 1989, the stream almost dried up; during the flood of the century in 1999, 13.6 cubic meters of water flowed through the stream every second.

fauna

In addition to microorganisms, the Orisbach is primarily the habitat of the brown trout, which is one of the endangered species . Corresponding investigations showed very good living conditions and populations in the upper reaches of the stream, which deteriorate progressively further down the stream (up to grade "moderate" in Liestal). Despite the very good brown trout population, other types of trout, especially the bullhead and loach , are missing.

Water condition

The water quality of the Orisbach is very good. The stream is not polluted with heavy metals. An extensive biological examination based on thirteen different test points also confirmed that the water quality was good.

Individual evidence

  1. a b Geoserver of the Swiss Federal Administration ( information )
  2. a b c Orisbach. (PDF) Position 4317: monthly samples. In: Canton Basel-Landschaft civil engineering office, hydraulic engineering division. Retrieved May 30, 2019 .
  3. a b Agreement on fishing in the Dorfbach Ruestelbach and Orisbach  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.so.ch  
  4. a b History of Liestal
  5. Report of the cantonal office for environmental protection and energy on the fish fauna 2007 (PDF file; 3.7 MB)
  6. Investigation of heavy metals in rivers 2007, p. 24 ff. (PDF file; 2.2 MB)
  7. Biological investigations 2007, p. 33 (PDF file; 3.4 MB)