Erlengraben (Alb)

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Erlengraben
Hertelgraben (in the middle course)
Petergraben (in the lower course)
ETO weir with rough ramp at the junction from the Alb

ETO weir with rough ramp at the junction from the Alb

Data
Water code DE : 2374758
location Upper Rhine Plain

Baden-Württemberg

River system Rhine
Drain over Alb  → Rhine  → North Sea
origin Branch from the Alb at the ETO weir in the north of Ettlingen
48 ° 57 ′ 1 ″  N , 8 ° 23 ′ 34 ″  E
Source height 121  m above sea level NN
muzzle from left and south into the Alb in the Karlsruhe district of Beiertheim-Bulach Coordinates: 48 ° 59 ′ 27 ″  N , 8 ° 23 ′ 19 ″  E 48 ° 59 ′ 27 ″  N , 8 ° 23 ′ 19 ″  E
Mouth height 114  m above sea level NN
Height difference 7 m
Bottom slope 1.3 ‰
length 5.5 km
Right tributaries Oberholzgraben
Big cities Karlsruhe
Medium-sized cities Ettlingen
Streich weir to divert high water into the pond forest

Streich weir to divert high water into the pond forest

Footbridge west of Rüppurr

Footbridge west of Rüppurr

The Erlengraben (rarely Erlenbach , in the middle course Hertelgraben , in the lower course Petergraben ) is a river arm of the Alb coming from the northern Black Forest . It branches off in the north of Ettlingen and flows back into the Alb after 5.5 kilometers near the Karlsruhe district of Beiertheim-Bulach .

course

The Erlengraben lies entirely in the Hardtebenen natural area of the Upper Rhine Plain . The Erlengraben partly follows old water courses of the Kinzig-Murg-Rinne , which flowed here in north-north-east directions.

The branch of the Erlengraben from the Alb lies in the extreme north of the Ettlingen urban area. The inflow to the Erlengraben is controlled by the so-called ETO weir, a contactor with two weir fields. One of the protective boards was removed in favor of a rough ramp to allow fish migration .

Running for around one kilometer in the Ettlingen urban area in a north-westerly direction, the Erlengraben crosses a number of traffic routes, including the Karlsruhe – Ettlingen – Rastatt railway , federal highway 3 and federal highway 5 , the latter two in the area of ​​the Karlsruhe Süd motorway junction .

At the motorway junction of Erlengraben leaves the Ettlinger urban area and follows at approximately 500 meters the main road 3. At the junction of the motorway to Karlsruhe proposes the Erlengraben north to north-east direction, and runs along the boundary between the Hardtwald the west and an agricultural area with several emigrant farms in the east. In this section, the water is partly the border between the Ettlinger and Karlsruhe districts.

At a prominent bend, the name of the water changes from Erlengraben to Hertelgraben. At this point there is a weir , over the flood can flow right into the pond forest. Below the Streich weir, the Hertelgraben follows a corridor for high-voltage lines in a northwesterly direction for around 600 meters and then changes again to a north to north-easterly direction of flow.

With the entry into the Weiherwald, the Hertelgraben finally reaches the Karlsruhe district. In the Weiherwald, the Hertelgraben flows from the right to the Oberholzgraben, which flows through the eastern part of the forest and to which the water flowing off the Streich weir arrives. North of the Weiherwald forest, the Hertelgraben crosses an area with allotment gardens and club houses. The flowing water then passes the grounds of the Karlsruhe depot of Deutsche Bahn and passes under an access track to the Karlsruhe freight yard and the Karlsruhe – Durmersheim – Rastatt and Winden – Karlsruhe lines .

North of the railway facilities, the name of the water changes from Hertelgraben to Petergraben and the direction of flow changes from northwest to northeast. The Petergraben runs between allotment gardens on the left and the railway area on the right, crosses other access tracks to the Karlsruhe freight yard and the southern bypass, which runs through the Edeltrauttunnel, a high-rise structure covered with greenery. Immediately north of the Edeltrauttunel and thus between the town centers of the Karlsruhe districts Bulach and Beiertheim , the Petergraben flows from the left and south into the Alb, which flows into the Rhine after around 16 kilometers .

The forests and agriculturally used areas through which the entire course of the Alder Trench flows belong entirely to the Hardtwald near Ettlingen and Rheinstetten (Ettlingen) and southern Hardt (Karlsruhe) protected landscape areas .

history

In the Karlsruhe area, water body names ending in “-graben” are often artificially created watercourses that are used for irrigation or drainage. However, it cannot be determined in detail whether it is natural or artificial water.

The name Erlengraben is recorded in the topographic map of the Grand Duchy of Baden published around 1840 ; it first appeared in the files of the city of Ettlingen in 1847. The name is derived from an alder forest , first mentioned in 1695 , which lay north of today's motorway and east of the alder trench. The area was called Alder Meadows after the forest was cleared in the 19th century .

The name Hertelgraben can be documented for the year 1554. It refers to the field name Hertel in the Ettlinger part of the Hardtwald. Hertel is the diminutive of Hardt and stands for a small pasture forest .

The name Petergraben is also included in the topographic map from 1840, but as the name of today's Oberholzgraben. In the archives, the Petergraben can be traced for the first time on a municipal map of Bulach from 1869. Both in an overview plan published by the Karlsruhe Civil Engineering Office in 1895 and continued until 1915 and in a city map from 1943, Petergraben describes a flowing body of water that starts at the moat around the Scheibenhardt estate and flows south of the Bahngelämdes near Bulach from the left into today's Hertelgraben. The lower part of this body of water operates today under the name Lohwiesengraben .

The name Oberholzgraben is first mentioned in 1856; it is derived from the 1461 verifiable Oberholz , a piece of forest that mainly belonged to the district of Rüppurr .

A bridge over a path over the Erlengraben directly on the railway line in Ettlingen, which was demolished in 1992, was one of the few testimonies to the early days of railway construction in Baden and had a special technical and historical significance: in 1988 it was recognized that the cast iron arches of the bridge were parts that the railway bridge over the Kinzig near Offenburg, completed in 1845 . The Kinzigbrücke collapsed in 1851 during a flood after a storm; in the same storm, the bridge over the Erlengraben was destroyed. Parts of the Kinzig Bridge that were still usable were used in 1852 for the bridge over the Erlengraben. Parts of the broken bridge are being kept in the Technoseum in Mannheim.

Flood

In the 20th century, floods in the Alb resulted in multiple floods at the Erlengraben. In January 1955, houses and streets in Ettlingen-West were flooded. A flood in January 1970 put roads in Ettlingen-West and the motorway junction under water. In addition, houses in the south of Bulach and the resettlers' farms east of the alder trench near Rüppurr were flooded. Bundeswehr soldiers were also deployed to evacuate the cattle from the emigrant farms. In May 1978, a renewed flooding of the emigrant farms was prevented by building a sandbag wall along the alder trench.

In both 1970 and 1978 the Alb flooded the motorway south of Rüppurr; the closure of the route caused traffic chaos in the Karlsruhe area. The flood in 1978 was the reason for the accelerated flood protection of the cities of Ettlingen and Karlsruhe. According to the plan approved in 1983 , the discharge capacity of water bodies was increased, dams were built and three retention areas were created. The concept was designed for an outflow of 71 cubic meters per second from the Alb in Ettlingen, which corresponded to the assumptions made at the time about a hundred-year flood. By 1998, DM 177 million had been invested.

In the course of the measures, the Erlengraben in the upper reaches was expanded to a discharge capacity of 20 cubic meters per second. One of the three retention areas is the Weiherwald, with an area of ​​0.77 square kilometers and a retention volume of 780,000 cubic meters. In the south-east and north, the Weiherwald is surrounded by flood dams in order to prevent the flooding of neighboring residential buildings, club facilities and allotment gardens. The Weiherwald is the first of the three retention areas to be flooded when the Alb discharge reaches 26 cubic meters per second.

A Alb flood in October 1998 with a maximum discharge of 96 cubic meters per second did not overload the flood protection system; according to a report by the North Upper Rhine Water Authority, the extent of the flood protection system did not reach the level of 1978.

A redefinition of the maximum discharge during a hundred-year flood of the Alb in 2008 resulted in a maximum discharge of 97 cubic meters per second in Ettlingen. For the dimensioning of flood protection systems, a climate change factor was introduced in Baden-Württemberg, which takes into account the higher flood risk associated with the more frequent heavy rain events caused by climate change . Taking climate change into account, the maximum discharge of the Alb in Ettlingen during a hundred-year flood is 111 cubic meters per second.

The cities of Karlsruhe and Ettlingen joined together in autumn 2003 to form a planning community to restore a hundred-year flood protection on the Alb. The core of the preferred solution that has now been developed is the construction of a retention basin in the Alb valley above Ettlingen. The retention area in the Weiherwald is to be equipped with a controllable outlet structure so that the retention volume can be better used. The discharge capacity of the alder trench is to be increased to 25 cubic meters and that of the Peter trench to 22 cubic meters per second through selective measures.

Web links

Commons : Erlengraben (Alb)  - Collection of images, videos and audio files

Individual evidence

LUBW

Official online waterway map with a suitable section and the layers used here: Course of the Erlengraben
General introduction without default settings and layers: State Institute for the Environment Baden-Württemberg (LUBW) ( notes )

  1. ↑ a b Heights determined from the digital terrain model of the online waterway map.
  2. ↑ Length according to the waterway network layer ( AWGN ) .
  3. ↑ a b Local names after the layer water names .
  4. ↑ Landscape protection areas according to the relevant layer.

Further evidence

  1. ^ A b Friedrich Huttenlocher , Hansjörg Dongus : Geographical land survey: The natural spatial units on sheet 170 Stuttgart. Federal Institute for Regional Studies, Bad Godesberg 1949, revised 1967. →  Online map (PDF; 4.0 MB)
  2. ↑ a b Flood alarm on Sunday morning at 5 a.m. In: Badische Latest Nachrichten , No. 1955-12, January 17, 1955, p. 6.
  3. ↑ Elena Beckenbach: Geological interpretation of the high-resolution digital terrain model of Baden-Württemberg. Hochschulschrift, Universität Stuttgart 2016, pp. 199, 202 ( download) .
  4. ↑ a b Ernst Schneider: The city district of Karlsruhe in the mirror of the field names. (= Publications of the Karlsruhe City Archives , Volume 1) CF Müller, Karlsruhe 1965, p. 11
  5. ↑ a b Topographisches Bureau Baden (ed.): Topographical map of the Grand Duchy of Baden: according to the general land survey of the Grand Ducal military topographical bureau. Karlsruhe, around 1840.
  6. ↑ Ernst Schneider: The field names of the city of Ettlingen. (= Contributions to the history of the city of Ettlingen , Volume 7) G. Braun, Karlsruhe 1980, p. 143.
  7. ^ Schneider, field names of the city of Ettlingen , p. 158 f.
  8. ^ Civil engineering office Karlsruhe (edit.): Overview plan of the capital and residence city of Karlsruhe with the outskirts of the city limits and adjacent areas. 1895, completed by 1915, plan 11.
  9. ↑ Surveying Office of the State Capital Karlsruhe (edit.): City Map State Capital Karlsruhe. Accessible via the menu background maps in the geoportal of the city of Karlsruhe .
  10. ^ Schneider, field names of the city of Ettlingen , p. 191.
  11. ↑ Ulrich Boeyng: The bridge over the Erlengraben near Ettlingen - a monument from the early days of the Grand Ducal Baden Railway. In: Denkmalpflege in Baden-Württemberg , Volume 18, No. 3 (1989), pp. 148-163 ( online ).
    Klaus Stiglat: Bridges on the way. Early iron and concrete bridges in Germany and France. Ernst, Berlin 1997, ISBN 978-3-433-01299-4 , p. 66 f.
  12. ↑ Large parts of the Alb valley are flooded by floods. In: Badische Latest Nachrichten , No. 108–1970, May 12, 1970, p. 13;
    The motorway is passable again. In: Badische Latest Nachrichten , No. 111-1970, May 15, 1970, p. 31;
    The situation is normalizing. In: Badische Latest Nachrichten , No. 112 / 113–1970, May 16, 1970, p. 47.
  13. ↑ Volker Strobel: The "flood of the century". 50 million liters of water were pumped off the A 5 at Rüppurr. In: Diary of the fan-shaped city. Karlsruhe in retrospect. Volume 2, Info-Verlag, Karlsruhe 1978, pp. 19-24.
  14. ^ State Institute for Environmental Protection Baden-Württemberg (Ed.): The flood of October, November 1998 in Baden-Württemberg: State Institute for Environmental Protection Baden-Württemberg; Karlsruhe 2001, ISBN 3-88251-275-X , pp. 104, 139;
    Unger Ingenieure, Jestaedt + Partner: HWS Alb. Restoration of the 100-year flood protection on the Alb for the cities of Ettlingen and Karlsruhe at the spinning mill. Scoping process. Document for the discussion of the probable scope of the investigation according to § 5 UVPG. On behalf of the cities of Ettlingen and Karlsruhe, as of February 13, 2015, p. 16 (pdf, 1.6 MB).
  15. ↑ Unger, Jestaedt, restoration of the 100-year flood protection , p. 4.
  16. ↑ Unger, Jestaedt, restoration of the 100-year flood protection , p. 7.