Gründlach

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Gründlach
Gründlach flows through Heroldsberg

Gründlach flows through Heroldsberg

Data
Water code DE : 24234
location Germany
River system Rhine
Drain over Regnitz  → Main  → Rhine  → North Sea
source in Kleingeschaidt
49 ° 33 ′ 25 ″  N , 11 ° 10 ′ 32 ″  E
Source height approx.  405  m above sea level NN
muzzle near Eltersdorf in the Regnitz coordinates: 49 ° 32 '35 "  N , 10 ° 58' 39"  E 49 ° 32 '35 "  N , 10 ° 58' 39"  E
Mouth height 278  m above sea level NN
Height difference approx. 127 m
Bottom slope approx. 6.4 ‰
length approx. 20 km
Catchment area 99.2 km²
Discharge
A Eo : 35.02 km² 		NNQ
MNQ
MQ
Mq
 MHQ
HHQ (1995) 		8 l / s
41 l / s
259 l / s
7.4 l / (s km²)
 4.67 m³ / s
8.06 m³ / s

The Gründlach is a short right-hand tributary of the Regnitz in Middle Franconia ( Bavaria ) and a second order body of water.

geography

course

The Gründlach rises in Kleingeschaidt , flows through the community-free area Geschaidt and then through Heroldsberg , where it meets the Bosenbach coming from Kalchreuth at the waterworks . On the southern outskirts of the village flows at Günthersbühl (city of Lauf an der Pegnitz ) at about 420  m above sea level. NN ( 49 ° 32 ′ 7 ″  N , 11 ° 12 ′ 54 ″  E ) rises from the Simmelberger Gründlach and the Gründlach passes under the Graefenbergbahn . From there it forms the border between Heroldsberg and Geschaidt, later between the Kalchreuther Forst and Geschaidt. In the Sebalder Reichswald it crosses the community-free areas of Kraftshofer Forst , in which the course of the stream is very winding, and Neunhofer Forst .

After passing under the A 3 the Gründlach reached Nuremberg city area. The road to Kalchreuth can flood here in autumn and spring. Shortly after leaving the forest, the “Lachgraben” branch off to the south, which passes Neunhof on the northern edge. The Kothbrunngraben, which rises east of Buchenbühl , flows into Boxdorf . At Großgründlach the Gründlach flows into the Nonnengraben . Then it crosses Kleingründlach and finally flows into the Regnitz after about 20 km near Eltersdorf .

Tributaries

  • Bosenbach ( right )
  • Simmelberger Gründlach ( left )
  • Gockerlersbr. Ditch ( right )
  • Nonnengraben ( right )
  • Kothbrunngraben ( left )
  • Weidengraben ( right )
  • Swallow number ditch ( left )
  • Bucher Landgraben - Hirschsprunggraben ( left )
Typical meander formation of the Gründelbach

Hydrology

Morphological flow type

With the exception of a few regulated sections in the area of ​​localities with a total of only a small proportion of the total length, the Gründlach flows predominantly in free windings in its own alluvial land ( Alluvion ). The flowing water has only one main arm, the lateral development of which in the alluvial floodplain leads to erosion on the concave steep banks (impact slope) and deposition (accumulation) on the convex banks of the inner banks (sliding banks). The natural sections are characterized by a high proportion of dead wood.

Runoff regime

The Gründlach has a complex runoff regime . The mean discharge curve shows a multi-peak annual course and corresponds to the rain-snow regime (pluvio-nival regime). The flow of water in the body of water is determined by rain and snowmelt.

Geotope

About one kilometer west of Heroldsberg, the course of the river is designated as geotope 572R002 by the Bavarian State Office for the Environment . The Gründelbach meanders here over a longer, unspoilt stretch and forms numerous sliding and impact slopes .

nature and environment

Water quality

Near-natural, deadwood-dominated section of the river Gründlach north of Boxdorf (Nuremberg)

Biological water quality

The biological water quality of the flowing water based on the saprobic system is rated in the upper reaches to the east of the A3 motorway with quality class II. The Gründlach shows only moderate loads in the forest-shaped section. This corresponds to the good status according to the European Water Framework Directive (WFD). In the Nuremberg city area, west of the A3, quality class II-III dominates due to the agricultural use in the vicinity of the water body (moderate condition according to WFD).

The water quality has continuously improved since 1974. In the past, impermissible withdrawals of water were made from the Gründlach during dry periods in summer when the water level was low. In the course of the addition of irrigation water for agriculture from the Rednitz (transition from Altmühl and Danube) by the Knoblauchsland water association, these withdrawals were no longer necessary.

Chemical condition

In the upper reaches of the A3, the Gründlach is in good chemical condition according to the WFD. The flowing water and the groundwater body , on the other hand, have a very high nitrate load of over 50 mg / l due to the intensive agricultural land use in the Nuremberg city area. Therefore, the chemical status is classified as poor. The nitrogen surplus from farm manure and mineral fertilizer associated with intensive vegetable cultivation and arable farming, in connection with the very easily permeable sandy soils of the garlic country, leads to greater groundwater pollution.

Ecological condition

Sooswiesen in the Gründlachau meadows northeast of Neunhof (Nuremberg)

The ecological condition in the upper reaches of the Gründlach is rated as moderate and in the lower reaches only unsatisfactory. The ecological status of a river according to the WFD compares the organisms living in the water with the population that would occur naturally. Since the water-related communities ( macrozoobenthos , phytobenthos , phytoplankton and fish) reflect all anthropogenic influencing factors and disturbances, this classification is suitable for biological quality components of the water body. In the lower reaches, the invertebrates living on the bottom of the water (macrozoobenthos) and the algae (phytobenthos) adhering to the bottom of the water are in an unsatisfactory condition. The aquatic plants and algae are indicator plants for nutrient pollution. The fish fauna is also only rated as moderate over the entire course of the river.

The aim of the European Water Framework Directive (2000/60 / EG) is to create a good or very good ecological status for natural flowing water.

fauna and Flora

fauna

Fish fauna

The Gründlach and Lachgraben offer suitable habitats for small fish such as minnow (Phoxinus phoxinus) , Moderlieschen (Leucaspius delineatus) and sticklebacks (Gasterosteidae).

Mammals

The protected beaver (Castor fiber) occurs on the Gründlachau floodplains in the city of Nuremberg and local floods due to its dam structures. The softwood meadows and widely branched backwaters of the Gründlach offer ideal habitat conditions for the rodent, which was already extinct on the river by the middle of the 20th century. In 1970 four beavers from Sweden were reintroduced north of Nuremberg on the Gründlach in the Sebalder Reichswald.

The occurrence of the very rare wildcat ( Felis silvestris ) has been genetically proven in the Gründlachtal.

Avifauna

The steep banks of the Gründlach offer the kingfisher ( Alcedo atthis ) water-free nesting opportunities . The good range of small fish and sitting guards completes the necessary habitat structures for the colorful guide bird of the flowing waters. The endangered water rail (Rallus aquaticus) is native to the Gründlachau meadows .

Extensive meadow complexes of the Grünlachauen near Neunhof - the landscape protection area Gründlachtal-Ost is the habitat of numerous meadow breeders

The Grünlach floodplains in the Nuremberg urban area, east of Erlangener Straße and west and south of Großgründlach, represent habitats for meadow and ground breeders such as lapwing (Vanellus vanellus) , skylark (Alauda arvensis) and wagtail (Motacilla flava) .

flora

On the sites along the Gründlach, to the east of the A3, characterized by groundwater and flooding, blossom-rich wet meadows and gallery forests consisting of softwood meadows developed .

Protected areas

Recreation

The Gründlachtal was a popular local recreation area in the north of Nuremberg as early as the 1970s.

literature

Web links

Commons : Gründlach  - Collection of images, videos and audio files

Individual evidence

  1. ^ Main flood action plan
  2. ↑ Bavarian flood news service (as of September 6, 2011)
  3. ^ Flood news service Bavaria: outflow Frauenkreuz / Gründlach. Bavarian State Office for the Environment (LfU), accessed on February 9, 2018 .
  4. ↑ Some Hydrogeography of Central Europe. University of Bayreuth, Chair of Geomorphology, accessed on February 9, 2018 .
  5. ↑ Geotope: Gründlach east of Heroldsberg (572R002) (accessed on March 4, 2014)
  6. ↑ a b c Written question from MP Arif Tasdelen SPD from 02.03.2017. Bavarian State Parliament, May 30, 2017, accessed on February 9, 2018 .
  7. ^ State of small rivers in Nuremberg. City of Nuremberg, urban drainage and environmental analysis, 2006, accessed on February 8, 2018 .
  8. ↑ a b c d Nuremberg's landscape treasures - nature on the doorstep. VGN, Nuremberg Environment Agency, July 2017, accessed on February 13, 2018 .
  9. ↑ Species and biotope protection program Bavaria City of Nuremberg. Bavarian State Ministry for Regional Development and Environmental Issues, March 1996, accessed on September 5, 2017 .
  10. ↑ Wildcats again in the Sebalder Reichswald. In: Nürnberger Nachrichten. Verlag Nürnberger Presse, May 5, 2015, accessed on May 18, 2019 .
  11. ↑ Nadja Danner, Sarah Green Fields: Habitat and breeding pairs *. City of Nuremberg, Environment Agency, April 7, 2017, accessed on February 10, 2018 .
  12. ↑ Green List of Landscape Protection Areas in Bavaria. Bavarian State Office for the Environment (LfU), July 15, 2016, accessed on August 6, 2017 .
  13. ↑ Area data NATURA 2000: Area no. 6533-471 Area name Nuremberg Reichswald. Bavarian State Office for the Environment (LfU), accessed on August 6, 2017 .
  14. ↑ 6432-371 Irrhain (FFH area). Published by the Federal Agency for Nature Conservation . Retrieved February 5, 2019.
  15. ↑ Friebgard scraper: reintroduction of beavers - Development of a beaver colony near Nuremberg . In: Communications from the Braunau Zoological Society . tape 2 , no. 12/14 , October 23, 1976, pp. 293 .