Langete

Langete
Langete in the center of Langenthal
Data
Water code	CH : 496
location	Mittelland Oberaargau Switzerland Canton Bern Oberaargau administrative district
River system	Rhine
Drain over	Murg  → Aare  → Rhine  → North Sea
source	near the town of Eriswil , at the Ahorn 47 ° 3 ′ 24 ″  N , 7 ° 50 ′ 23 ″  E
Source height	approx.  900  m above sea level M.
confluence	with the red to Murg in Murgenthal ( canton Aargau ) Coordinates: 47 ° 15 ′ 5 ″  N , 7 ° 49 ′ 35 ″  E ; CH1903:  629 360  /  233 446 47 ° 15 '5 "  N , 7 ° 49' 35"  O
Mouth height	420  m above sea level M.
Height difference	approx. 480 m
Bottom slope	approx. 15 ‰
length	31 km
Catchment area	131 km²
Outflow A Eo : 131 km²	MQ Mq	2.55 m³ / s 19.5 l / (s km²)
Left tributaries	Rotbach , Ursenbach
Right tributaries	Schwändibach, Nyffelbächli
source muzzle Source and mouth of the Langete

The Langete (also called Langeten ) is a small river in the Swiss canton of Bern . Its length is 31 km and its catchment area 133 km². It is the left and southwestern headwaters of the Murg .

Surname

“Langete” is the dialect for both the river and the city of Langenthal . The name probably goes back to the Old High German term langata (plural), which referred to the rivulets in the flooded infiltration area of ​​a river. The name suggests that the Langete seeped into the gravel field of Langenthal until the early Middle Ages .

course

The Langete in Eriswil

The Langete rises near the town of Eriswil , on the Ahorngrat (part of the Napf massif ) at 1100  m above sea level. M. and takes on the Rotbach in Huttwil and the Ursenbach in Kleindietwil . As far as Lotzwil it runs as the deepest line through the valley floor, further downstream it flows partly in the accumulation profile above the surrounding level.

After the confluence with the Rot at 450  m above sea level. M. near Roggwil the Langete merges into the Murg and flows west of Murgenthal into the Aare .

Hydrology

Data

The runoff of the Langete at the Lotzwil measuring station is a long-term average of around 2 m³ / s. The relatively even water flow - the mean monthly runoff is between 1.7 m³ / s in October and 2.5 m³ / s in March - are offset by considerable fluctuations in the extreme individual values: in the summer of 1947 (as a result of discharge on the water mats ) only 0.05 m³ / s recorded, with the "flood of the century" of August 30, 1975 over 90 m³ / s.

The temperature of the Langete varies between 4 ° C (monthly mean in January) and 16 ° C (in August) and occasionally reaches 18 ° C.

Flood protection

Catastrophic floods with floods occurred on the Langete in 1663, 1664, 1733, 1762, 1781, 1816, 1852, 1888, 1904, 1910, 1931, 1940, 1962, 1972, 1975 and 2007. The flood of June 8, 2007 claimed three lives in the upper Langetental.

Since time immemorial, floods in the Langetental have been diverted to seepage onto water mats . In Langenthal there has been an additional discharge into the Hardwald since 1903. The streets of the city center with their high sidewalks are laid out like a canal for this purpose; they used to be flooded on average twice a year. However, the capacity of this discharge is limited to 20 m³ / s, so that flood damage repeatedly occurred in Langenthal. The 1975 floods alone caused property damage of at least CHF 60 million in the region. Subsequently, the municipalities of Aarwangen , Langenthal, Leimiswil , Lotzwil , Madiswil and Roggwil founded the Lower Langetental Flood Protection Association under pressure from insurance companies. The association realized (with financial support from the federal government and the canton) 1988–1991 the construction of a 7531 m long relief tunnel that can divert up to 58 m³ / s from the inlet structure below Madiswil directly into the Aare near Bannwil. The relief tunnel made previous plans for a canalization of the Langete or the construction of retention basins superfluous and enabled a near-natural correction of the channel, which was completed in 1995 under the direction of the flood protection association. The total costs of the relief tunnel and the correction amounted to around CHF 90 million.

nature and environment

Wastewater treatment

Out of concern for the groundwater in the Hardwald, Langenthal built the region's first (mechanical) wastewater treatment plant in 1952 . Later on, special-purpose associations from several municipalities implemented additional facilities in Lotzwil (1968), Rohrbach (1973) and Dürrenroth. In addition, there were isolated small sewage treatment plants . As a result, the water quality of the Langete improved slightly, but remained unsatisfactory overall.

In 2000, the municipalities responsible for the sewage treatment plants in Aarwangen, Langenthal, Lotzwil and Rohrbach decided to replace their operations in need of renovation with a central, modern plant near Aarwangen . This necessitated the expansion of the inlet systems and the construction of a 2070 m long waste and rainwater tunnel through the Muniberg. The wastewater treatment plant Eymatt (near Aarwangen), inaugurated in 2004, is operated by ZALA AG on behalf of 17 municipalities. It has a cleaning capacity of 65,000 population equivalents and uses the Aare as a powerful receiving water ; the Langete was accordingly relieved of sewage.

fishing

The Langete is occupied by the holders of fishing rights with brown trout ; in addition, stocks of ash and rainbow trout persist due to natural spawning. The population of bullheads has been greatly reduced. Minnows and jackdaws , which used to be common, have become extinct.

In the aquatic invertebrates, little-bristle , mosquitoes and mayflies dominate . In the upper reaches (up to Huttwil) there are also demanding stoneflies and caddis flies .

use

Use of hydropower

The slope of the Langete was already used as a source of energy by businesses in the early Middle Ages: the mills in Eriswil, Huttwil, Rohrbach, Kleindietwil, Lindenholz, Lotzwil and Langenthal were powered by water wheels, as were sawmills, milling, ramming and pressing . Commercial water use took precedence over agricultural use (namely irrigation).

At the end of the 19th century, commercial hydropower plants with a total output of around 500 hp were in operation in the Langetental. In accordance with the cantonal license, the Langenthaler mill ran with an output of 37 hp, and the Gugelmann textile works in Roggwil had installed a 70 hp turbine to drive their looms mechanically in 1875 .

Even after the construction of a power station on the Aare near Wynau and the associated introduction of electricity supply (1896 in Langenthal, extended to Huttwil in 1901/02), the Langete remained an important source of mechanical energy for local mills and sawmills for decades.

The Langete has recently also been used to generate electricity: In 1987, the municipality of Roggwil commissioned a small electric hydropower plant, which generates an output of 250 kW from a gross gradient of 9 m and feeds it into the grid. In Lotzwil, private investors built a 130 kW system in 1994.

Use of groundwater

The water exfiltrating from the Langete and seeping through the water mats, together with precipitation and lateral tributaries, feeds a groundwater flow that is indispensable for the drinking water supply in the region. Langenthal has been getting the raw material for its municipal water supply from a groundwater surge in Madiswil since 1894; efficient pumping stations have been in operation in the Hardwald since 1951. The municipal association for water supply in lower Langete WUL has been managing the region's groundwater since 1983 and is the primary supplier of water for over 30,000 residents in eleven municipalities.

The springs from the groundwater in the Roggwiler Brunnmatt are used there for the cultivation of watercress .

Water mats

In Langetental is for about a thousand years Water-meadow operated. This is how the cultural landscape of the Wässermatten was created.

The relatively sterile, but well-drained gravel areas in the natural floodplain landscape of the Langete did not offer favorable conditions for agriculture. Only through the artificial irrigation with the suspended matter-rich water of the Langete could a soil formation gradually be achieved through colmation , which improved the supply of nutrients. This amelioration was the work of medieval landlords (namely the Cistercians of the St. Urban monastery ) as well as the farmers who founded cooperatives for the common use of irrigation systems. The spatial and temporal allocation of water as well as maintenance obligations were regulated in sweeping regulations; A water authority was responsible for their enforcement. The mats were mainly used as hay meadows, sometimes also as pastures.

In the 20th century, especially after 1950, most of the water mats were turned into arable land or sealed as building land ; in the Langetental their area decreased from around 700 to 80 ha. The interests of the water supply ( groundwater recharge ) and the protection of the landscape then gave impetus to the preservation of a remaining stock of water mats: These were included in the federal inventory of landscapes and natural monuments of national importance by the Swiss Federal Council in 1983 . The Wässermatten Foundation, founded in 1992 by the canton of Bern, has been maintaining this cultural landscape and ensuring traditional meadow irrigation by concluding contracts with individual farmers and compensating them for additional work and reduced yield.

literature

• V. Binggeli: Geography of the Oberaargau. Special volume 3 for the Oberaargau yearbook, Langenthal 1983.
• V. Binggeli: The water mats of the Oberaargau. Special volume 4 for the Oberaargau yearbook, Langenthal 1999, ISBN 3-907012-35-6 .
• C. Leibundgut: Meadow irrigation systems in the Langetental. Geographica Bernensia G41, Bern 1993, ISBN 3-906290-79-4 .
• Flood protection association lower Langetental .: The taming of the Langete. Langenthal 1998. (online, PDF)
• Heike Schmidt-Posthaus: Synthesis report Problem fish decline Langeten. Bern 2003. (online, PDF)

Web links

Commons : Langete  - collection of images, videos and audio files

• Max Jufer: Langeten. In: Historical Lexicon of Switzerland .
• Website of the Langetental wastewater region

Individual evidence

1. ↑ ^{a b} Geoserver of the Swiss Federal Administration ( information )
2. ↑ Evaluations of the water network. (XLSX) (No longer available online.) FOEN , December 2013, archived from the original on June 13, 2018 ; Retrieved on August 9, 2017 (listing of Swiss rivers> 30km). Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice.  
3. ↑ ^{a b} Topographical catchment areas of Swiss waters: area outlets. Retrieved May 30, 2019 .