Hard levels

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The Hardtebenen are a natural spatial unit in the Upper Rhine Plain in Baden-Württemberg in the south-west German layer level country with the designation 223 according to the manual of the natural spatial structure of Germany .

ground

In the Hardt Plains the sandy and gravelly gravel surfaces of the lower terrace of the Upper Rhine from the Young Quaternary occur, lowlands that cross them, loamy lowlands on the break edges and the scenic inland dunes on the western and northeastern edge, which only occur here nationwide. The soils have a very low filter and buffer capacity and are mostly dry, except in the south and in the gravel mining areas. The nutrient-poor and water-permeable soils of gravel surfaces are mainly pine forest forested and are used intensively for agriculture. These peripheral areas exceed the acid inputs of the critical load agreed by the UN - ECE countries . Acidic, sandy substrates are mostly in the dunes - and shifting sands fields of Hardt level and in the slopes of the sandstone - Odenwald to find.

water

The Hardt Plains consist of medium to high loose rock (0.001 - 0.01 m³ / s), in the north (near Bruchsal ) and in the south its hydrogeological capabilities are highest, with an average leachate rate (200 - 400 mm / a), in the north lower (<200 mm / a). The groundwater is geogenically from Ca HCO³-watering and is only thinly covered. The subsoil forms gravel from the Rhine ditch and is filled with the most groundwater in the country . The banks of the rivers in the Hardt Plain are very remote from nature and their morphological condition is very low. Periodic flooding occurs only in the north and south. There are many water protection areas and thermal water resources worthy of protection near Bad Schönborn and Langenbrücken . The nitrate pollution of the groundwater is low (<25 mg / l), except in the north in the Kraichbach lowlands , where gravel and sand have been mined intensively for decades (> 50 mg / l).

air

Due to the location of the trench, the air exchange conditions are very poor. The Hardt Plain, especially north of Karlsruhe, has high ozone and nitrogen immission in large parts , which is above the critical level agreed by the UN-ECE countries .

raw materials

At the moment, the near-surface, medium to high gravel deposits in the Upper Haardt , the Alb-Saalbach lowlands and the Kraichbach lowlands are being used intensively. In addition, sand, gravel sand, quartz sand and grit are mined, and in the north brickworks raw materials such as clay, mudstone , marlstone , loess and loess loam.

natural reserve

The river and floodplain habitats , especially Kraichbach , Pfinz and the Duttlacher Graben , are particularly subsidized by the state as supplementary areas for species in need of protection in the Rhine floodplains . There, as in the floodplain landscapes on the Upper Rhine , western Hardt plain, continuous and near-natural flowing waters are to be developed. The intensive gravel and sand mining resulted in numerous quarry ponds.

Also are particularly vulnerable habitats of dunes and sands fields , the nation's major, heat-loving Alteichenbestände in the Hardt forests , the Green Country habitats in the floodplain, the remaining lowland forests on the edge of sink that reedbeds on the standing water , which extensively used Sandäcker habitats , the clearings and the orchard area on the northern edge of the Kinzig-Murg-Rinne , a supra-regionally important wetland and swampy lowland with extensive fens , reed beds, alder forests , alder- ash forests and wet grassland . All ecological development measures take place within the framework of the coherent European network of special protection areas Natura 2000 .

The Keulhornbiene ( Melitturga clavicornis ) came earlier in the Hardt level , in the Kraichgau , in Freiburg Bay , the Kaiserstuhl and Markgräflerland hills before and was last detected 1954th It has not been found since then and is on the Baden-Württemberg Red List of Bees (hazard category 0).

Adjacent natural areas

Neckar and Tauber Gäuplatten (12 / D57)

Black Forest (15 / D54)

Middle Upper Rhine Lowland (21 / D53b)

Northern Upper Rhine Lowland (22 / D53c)

literature

  • LfU, aquatic area directory
  • LVA, digital elevation model
  • IPF Karlsruhe, satellite image classification
  • Digital landscape-ecological atlas 1996
  • Hydrological Atlas of the FRG
  • E. Meynen, J. Schmithüsen (ed.), Handbook of the natural spatial structure of Germany , Federal Institute for Regional Studies, Remagen, 3rd edition
  • H. Reck / Walter / Osinski / Heinl / Kaule, Spatially differentiated protection priorities for species and biotope protection in Baden-Württemberg (target species concept) , expert opinion on behalf of the State of Baden-Württemberg, Institute for Landscape Planning and Ecology, University of Stuttgart, 1996, 1730 S.

Web links

Individual evidence

  1. ↑ State Office for Geology, Raw Materials and Mining, Freiburg, 1999
  2. ↑ LfU, overview mapping of morphological closeness to nature 1992/93
  3. ↑ MELUF, flood plains
  4. ↑ Geological State Office, Freiburg, 1996/1
  5. ↑ ILPÖ / IER, target species concept