Major hydrogeological districts of Germany
Major hydrogeological districts of Germany
1 North and Central German Unconsolidated Rock District
The North and Central German Unconsolidated Rock District covers most of the North German Plain - its southern parts extend as far as Saxony. It is characterised by the presence of thick Tertiary and Quaternary unconsolidated rock sequences with several overlying productive pore aquifers. The aquifers are of great importance for the water supply of northern and central Germany.
2 Rhenish-Westphalian Lowland
The Rhenish-Westphalian Lowlands in the Rhineland is characterised by very thick Tertiary unconsolidated rocks with cyclic sequences of sands, clays and lignite beds, which form a multi-layered aquifer system. Like the overlying and highly productive Quaternary terrace deposits, they are intensively used for water supply. The Westphalian area (Münsterland Cretaceous Basin) is characterised by productive, mostly sandy Cretaceous aquifers.
3 Upper Rhine Graben with Mainz Basin and North Hessian Tertiary
The Upper Rhine Graben with the Mainz Basin and the Tertiary in northern Hesse is characterised by the active subsidence zone of the Rhine Valley filled with Cenozoic unconsolidated sediments and the sedimentation areas of the Tertiary marine zone. The unconsolidated rocks (pore aquifers) contain productive groundwater resources, whereas the Tertiary carbonate and sedimentary rocks are of lesser importance for groundwater extraction.
4 Alpine Foreland
The major hydrogeological district Alpine Foreland is an active foreland basin south of the Danube River, filled with sediments of varying grain size composition from the surrounding mountains. The Cenozoic sedimentary rocks contain productive pore aquifers, often with embedded aquitards. Beneath this molasse basin, the south-dipping Malmtafel forms a rich deep aquifer. This fissured/karst aquifer carries mineral and thermal water with increasing depth in the south.
5 Central German Fault-block Land
The Central German Fault-block Land is characterised by the widespread occurrence of tectonically affected Mesozoic sedimentary units, which form moderately to very productive fractured or fractured/porous and fractured/karst aquifers. Fissured aquifers with increased water transport capacity are observed in tectonic fault zones. The Triassic aquifers in the centre of the Thuringian Basin and the Permian aquifers at the edge of the basin and in eastern Hesse are important for water supply. Deposits of Zechstein salts in the subsurface cause the mineralisation of the groundwater in the Subhercynian Basin.
6 West and South German Scarplands and Fault-block Land
Sedimentary Mesozoic rock units, largely covered by loess sediments, are widespread in the major hydrogeological district West and South German Scarplands and Fault-block Land. The hydrogeological conditions are characterised by a sequence of aquifers and aquicludes and the resulting multi-layer structure. These are essentially fractured, fractured and porous, and fractured and karst aquifers. Groundwater flow across the different aquifers is mainly associated with fissure and fault zones.
7 The Alps
The major hydrogeological district of the Alps is a Central European collision mountain range with active tectonics. Within Germany, parts of the Alps are only found on the southern edge of Bavaria - in the form of the Northern Alps, which are characterised by a fold and overthrust structure. The bedrock here consists mainly of fractured and fractured/karst aquifers with low, and in some areas highly variable, yields. Unconsolidated aquifers (Quaternary gravels), some with very high yields, are also found in the valleys filled with erosional debris from the Alps.
8 West and Central German Basement
The West and Central German Basement is characterised by Palaeozoic sedimentary and slightly metamorphic rocks of the Rhenish Massif, the Harz Block and the Halle-Wittenberg Block. In addition, there are the Rotliegend volcanites of the latter blocks, the volcanites of the Eifel (Quaternary, Tertiary) and the Westerwald (Tertiary), and the fluviatile deposits along watercourses. The Precambrian part of the Variscan basement is exposed in the metamorphic rocks of the Kyffhäuser crystalline. The fractured aquifers of this major hydrogeological district are generally of secondary importance for groundwater extraction.
9 Southeast German Basement
The Southeast German Basement covers contiguous and extensive basement uplifts or uplands with the same or similar hydrogeological characteristics in the federal states of Bavaria, Saxony and Thuringia. In terms of structural geology, the Saxothuringian includes the Thuringian Forest, the Thuringian-Franconian and Vogtland Slate Mountains, the Fichtelgebirge-Erzgebirge Mountains, the Elbe Zone and the Lusatian Granodiorite Complex. The Upper Palatinate and the Bavarian Forest are geotectonically classified as Moldanubic. Fractured aquifers or aquitards with mostly narrow catchment areas predominate. Accordingly, with a few exceptions, only low to moderate groundwater flows can be expected in the bedrock units.
10 Southwest German Basement
The Southwest German Basement represents the continuation of the Variscan orogen (Bohemian Massif) to the west (France, Spain), but is only partially exposed. It is characterised by higher metamorphic units and granites. The major hydrogeological district includes the areas of crystalline rocks (metamorphites and plutonites) in the Black Forest, Odenwald and Spessart, as well as metamorphic and non-metamorphic Palaeozoic rocks preserved in troughs and tectonic grabens. The rocks form aquitards, with groundwater flow largely limited to the near-surface loosening zone and weathering blankets. Evidence of deep circulation systems are mineral and thermal water uplifts in morphological lowlands associated with fractures and faults.