Gera (river)
| Gera | ||
 The catchment area of the Gera |
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| Data | ||
| Water code | EN : 5642 | |
| location | Central Thuringia , Germany | |
| River system | Elbe | |
| Drain over | Unstrut → Saale → Elbe → North Sea | |
| Beginning as Gera | The confluence of the Wilder and Zahmer Gera in Plaue 50 ° 46 ′ 30 ″ N , 10 ° 53 ′ 45 ″ E |
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| Source height | approx. 950 m (Wilde Gera) 330 m above sea level NN (confluence) |
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| muzzle | In the Unstrut near Gebesee coordinates: 51 ° 7 ′ 35 ″ N , 10 ° 55 ′ 40 ″ E 51 ° 7 ′ 35 ″ N , 10 ° 55 ′ 40 ″ E |
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| Mouth height | approx. 150 m | |
| Height difference | approx. 180 m | |
| Bottom slope | approx. 2.1 ‰ | |
| length | 85 km | |
| Catchment area | 1,089.9 km² | |
| Discharge at the Erfurt – Möbisburg A Eo gauge: 842.8 km² Location: 29.7 km above the mouth |
NNQ (September 24, 1959) MNQ 1931–2014 MQ 1931–2014 Mq 1931–2014 MHQ 1931–2014 HHQ (April 13, 1994) |
480 l / s 1.37 m³ / s 5.77 m³ / s 6.8 l / (s km²) 55.1 m³ / s 220 m³ / s |
| Discharge at the mouth of the A Eo : 1,089.9 km² |
MQ Mq |
6.6 m³ / s 6.1 l / (s km²) |
| Left tributaries | Lütsche , Wilde Weisse , Apfelstädt | |
| Right tributaries | Reichenbach , Wipfra | |
| Big cities | Erfurt | |
| Medium-sized cities | Arnstadt | |
| Small towns | Plaue , Gebesee | |
| Communities | Geratal (OT Geraberg and Graefenroda ), Wachsenburg Office (OT Ichtershausen ), Elxleben | |
| Residents in the catchment area | approximately 305,000 | |
 The diked Gera on the lower reaches of Andisleben |
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The Gera is an 85 kilometer long right (southern) tributary of the Unstrut in Thuringia .
geography
The Gera is created in Plaue by the confluence of the Wilder Gera (its western source river) and Zahmer Gera (its eastern source river). The sources of Wilder and Zahmer Gera are located in the Gehlberg district of the city of Suhl am Rennsteig in the Thuringian Forest on the slopes below the Schneekopf. The Gera initially flows in a northerly direction from Plaue via Dosdorf and Siegelbach to Arnstadt . This section of the valley is called Plauescher Grund . It is cut deep into the shell limestone , on the right the Reinsberge rise 300 meters above the river valley, on the left is the Gosseler Platte , which rises about 200 meters above the river valley. The river bed of the Gera has penetrated the shell limestone behind Plaue and initially flows like a bay on red sandstone; on the Bettelbach flowing towards the right, this bay even extends as far as the Paulinzella foreland . The final exit from the Ohrdrufer Platte , however, only takes place through the narrow breakthrough valley directly above Arnstadt.
In Arnstadt, the Geratal opens up when you reach Keuperstufe. It becomes noticeably wider and the slopes flatter on both sides. In Arnstadt, the Gera river bed has been largely straightened. The river here runs east of the city center. In Arnstadt, the Gera takes on the Wilde Weisse tributary . It is about 12 kilometers long and forms the Jonastal west of Arnstadt . The next place on the Gera is Rudisleben . Here the area is flat and the Gera no longer has a valley. Below Rudisleben follows Ichtershausen (municipality of Wachsenburg ). Behind Ichtershausen, the Gera takes on the Wipfra . It joins from the right and is about 40 kilometers long, but quite arid. The Gera now crosses under the A 71 , A 4 and the Geratalbrücke Ichtershausen (train) at the Erfurter Kreuz . She now also leaves the Ilm district and enters the area of the city of Erfurt . The next place shortly after the Erfurt cross is Molsdorf . To the north of the village, the 42-kilometer-long Apfelstädt joins the Gera. It is quite abundant in water, as its sources are also on the Rennsteig near Oberhof . Now Möbisburg and Bischleben , which already belong to the city of Erfurt, follow . The Thuringian Railway has been running in the Geratal since the mouth of the Apfelstädt .
The actual city of Erfurt begins behind Bischleben, initially with the district of Hochheim with its parks. The valley is noticeably steeper on both sides, the Steigerwald rises to the right and the Cyriaksburg citadel to the left . In Brühl , the Gera is divided into two arms: the Bergstrom and the Walkstrom , which unite in the old town to form the Breitstrom . These tributaries were mainly of economic importance, and numerous mills were operated on them. The Breitstrom (sometimes also called Wilde Gera), which flowed around the inner fortification ring, was of military importance. This was filled in during the founding period as part of the softening process. Its former course corresponds to that of today's Juri-Gagarin-Ring . The water was then diverted into the outer wall moat, today's flood ditch. Another mill flow, the deer poo, no longer exists either. Today only the street name Hirschlachufer reminds of the water.
The water of the Gera now flows with a maximum of 6.0 m³ / s through the old town, the rest of the flood ditch takes up. North of Erfurt's old town, the Gera runs through the Great Rieth to Gispersleben . Here the area is flat again and the Gera no longer forms a valley. In addition to the Gera, the B 4 runs to the west and the Erfurt - Nordhausen railway line to the east. This is followed by the Erfurt district of Kühnhausen and the towns of Elxleben , Walschleben , Andisleben , Ringleben and the town of Gebesee in the Gera-Aue in the Sömmerda district . The Gera joins the Unstrut on the right just after Gebesee . With a water flow of around 6.6 m³ / s it is the main flow of the Unstrut river system , because at the Gera estuary the Unstrut only carries around 4.6 m³ / s.
The narrow Gera branches off in Erfurt and flows east of the Großer Rieth via Mittelhausen , Riethnordhausen and Haßleben . It flows into the Gramme near Werningshausen with an average water flow of around 0.3 m³ / s and soon afterwards also reaches the Unstrut.
history
The original name of the river was Erfes (also Erphes , Erfis or Erphis ), from which the name of the Thuringian state capital Erfurt comes . The Latin name Hiera for Gera can also be found in the name of the old University of Erfurt as "Hierana" ( the one on the Gera ).
In the past centuries, the Gera often overflowed its banks with the consequence of severe flooding also for the Erfurt city center. That is why the elaborate construction of the flood ditch was built in Erfurt at the end of the 19th century , with which the city was successfully protected from such damage in the subsequent period.
environment
fauna
Brown trout are native to the upper reaches of the source streams of the Gera .
flora
The Plauesche Grund between Plaue and Arnstadt, where the climate is particularly mild, is particularly diverse . There you will find the flora characteristic of limestone.
Water quality
The water quality of the Gera was in 2013:
- In the section Plaue - district boundary IK / EF unsatisfactory
- In the city of Erfurt to Hochheim (Erfurt) good
- in the rest of the city and in the section up to the mouth moderate
Sights and buildings
The A 71 cuts the valleys of Zahmer and Wilder Gera and their tributary Reichenbach with three large bridges: the Reichenbach valley bridge (1000 meters long; 60 meters high), the Zahme Gera valley bridge (520 meters long; 70 meters high) and the Wilde valley bridge Gera (552 meters long; 110 meters high). Further bridge structures are the Geratalbrücke Ichtershausen (1121 meters long; 20 meters high) on the high-speed line Nuremberg – Erfurt and the bridges of the A71 and A4 in the area of the Erfurt cross.
The most famous structure over the Gera, however, is the Krämerbrücke in Erfurt, the only bridge north of the Alps that is completely built with houses.
Dams in the Gera catchment area are the Heyda , Lütsche , Ohra , Schmalwasser and Tambach-Dietharz dams in the Thuringian Forest and the Dachwig and Wechmar dams in its foreland.
economy
The Gera is of little economic importance. In the past it served as a drive for water mills and for rafting wood from the Thuringian Forest to Erfurt. Today it mainly supplies irrigation water for agriculture.
Others
- The Thuringian municipality of Geratal (in the Ilm district ) and two administrative communities have named themselves after the Gera :
- the administrative community Geratal / Plaue (in the Ilm district ; seat: Geratal , district Geraberg )
- the Gera-Aue administrative community (in the Sömmerda district ); Seat ( Gebesee )
- The Gera cycle path runs in the Gera valley .
- Until 1923 the place Geraberg was only called Gera .
- The poet Sidonia Hedwig zunemann drowned in Plaue in the Gera in a riding accident on a bridge in 1740.
Individual evidence
- ^ Thuringian State Institute for the Environment (ed.): Area and waterway key figures (directory and map). Jena 1998. 26 pp.
- ^ German Hydrological Yearbook Elbe Area, Part I 2014. (PDF) State Office for Flood Protection and Water Management Saxony-Anhalt, p. 176 , accessed on November 3, 2018 (from: lhw.sachsen-anhalt.de).
- ↑ a b c Level value of Erfurt-Möbisburg , increased by the drainage of the remaining catchment area, but without the Schmale Gera . The remaining catchment area is part of the intermediate catchment area of the Nägelstedt , Erfurt-Möbisburg and Wangen gauges ( Oldisleben excluded due to obviously incorrect MQ and MHQ values), which has an area discharge of 4.4 l / s km². The water of the Schmalen Gera only reaches the Unstrut after the Straussfurt Unstrut level has been bypassed . Therefore, the Mq value of the intermediate catchment area adjacent above is decreased and that of the one below is increased. This effect no longer occurs when taking into account an average flow rate of around 300 l / s for the Schmaler Gera. Therefore the arithmetically resulting discharge of the Gera is reduced from 6.9 m³ / s to 6.6 m³ / s. (For the Unstrut there is around 4.6 m³ / s.)
- ↑ Thuringian State Agency for the Environment: Map of the water quality 2013 (PDF), accessed on May 23, 2020
Web links
- The Gera near Erfurt-Web ( Memento from December 6, 2008 in the Internet Archive )