Some 10 % of Berlin has a depth to the water table of less than 2 metres, i.e. it is close to the groundwater. Approximately 22% of the city’s area is 2 to 4 metres above the water table and another 22 % about 4 to 10 metres. About 19% of Berlin has a depth to groundwater of 10 to 20 metres and another 19 % 20 to 40 metres. Great depths of more than 40 metres occur rather sporadically at higher elevations in about 9 % of Berlin’s area.
For areas where the quaternary main aquifer covered by boulder marl is not widespread but only occurs in isolated places (as described in the Methodology Chapter) the depth to groundwater is not included. Nevertheless, near-surface groundwater may occur in these areas in such quantities that it may even supply wetlands and their biocenoses with sufficient water (e.g. the upper Tegeler Fließtal near Lübars).
In the glacial spillway, depths to the water table typically range between 2 to 7 meters below the ground, decreasing towards the receiving waters of the Spree and Havel rivers. Many surface waters and their immediate surroundings are characteristically close to the groundwater, with depths to the water table of less than 2 metres. Relatively large areas with depths between 1 and 2 metres may also be found in the southern parts of the borough of Köpenick (north and south of the Langer See (lake)) as well as in the Spandauer Forst (forest), at the Heiligensee (lake) east of the Havel, and both to the north and south of the Rummelsburger Bucht (bay).
Greater depths (> 7 meters) in the glacial spillway are either due to morphological reasons (e.g. dunes within the Tegeler Forst (forest), east of the Müggelsee (lake), or in the Rehberge (hills)), or they are located in the catchment areas of waterworks wells (e.g. Spandau, Tegel, Friedrichshagen) and are caused by the current lowering of the groundwater.Greater depths to groundwater may also occur in small areas with confined groundwater conditions. Here, the depth to the water table is defined by the lower edge of the Weichsel Moraine covering the main aquifer.
In the plateau areas, the water table is usually located deep underground. The depth to groundwater mostly measures more than 10 metres here. The southern edge of the Barnim Plateau stands out in particular. In the eastern part of the Barnim Plateau, isolated depths of less than 10 metres occur in depressions (e.g. in the area around the Wuhle river). Otherwise, however, the groundwater in the Barnim Plateau is mostly more than 20 metres below ground, sometimes even more than 30 or 40 metres. In the Panke valley, on the other hand, there are large areas in the near-surface Aquifer 1 where the water table is close to the ground surface.
In the Grunewald (forest) and most of the area west of the Havel in Kladow and Gatow the groundwater is more than 20 metres below ground. Here, predominantly unconfined conditions prevail in the surrounding plateau sands, caused by morphological elevations (e.g. the hills Teufelsberg, Schäferberg, the Havelberge at the Grunewaldturm, and the Müggelberge in the forests of the borough of Köpenick).
The area of the Teltow Plateau between the Grunewald chain of lakes and the Teltowkanal (canal) is characterised by highly variable depths to groundwater between 7 and 30 metres. Similarly, the groundwater conditions fluctuate between confined and unconfined here. The area southeast of the Teltowkanal, on the other hand, is characterised by depths to groundwater of more than 20 metres and confined groundwater conditions. This area is further divided by the valley of the Rudower Fließ (stream). East of this, in Bohnsdorf and Alt-Glienicke, depths measure 20 metres and more again.
In unconfined areas, especially in the glacial spillway and the Panke valley, the water table is typically closer to the surface than in the plateaus, where groundwater conditions are often confined. Using the lower edge of the overlying aquitard as a point of reference emphasises the great depth at which the (confined) groundwater surface lies in areas with a thick boulder marl overburden. This is also reflected in big ‘jumps’ in the groundwater surface where confined groundwater borders on unconfined groundwater. At the edge of the unconfined Panke Valley aquifer, for example, the groundwater surface ‘jumps’ several tens of metres vertically upwards over a horizontal distance of a few hundred metres, which is the largest jump and can be observed at the eastern edge at the level of Blankenburg.
In some small areas near buildings or traffic routes, e.g. dams or underpasses, the depth to groundwater fluctuates considerably, which appears to be confusing initially. The high-resolution DTM1 supports this however, with elevation data that fluctuates clearly in these parts.
Compared to the Map “Depth to the Water Table” based on groundwater levels of May 2009, the data mainly differs where the improved elevation model was used in the current map. Otherwise, deviations are generally negligible and do not exceed one metre for the most part.
Overall, it was found that the relatively low groundwater levels of May 2020, which were used for the calculation (cf. Map 02.12 “Groundwater Levels of the Main Aquifer and Panke Valley Aquifer 2020”) are clearly evident in the glacial spillway and the Panke Valley of the current map. In contrast to the Map “Depth to the Water Table” of 2009, which presents medium groundwater levels, greater depths occur here in areas that are largely unconfined. This is often obscured by the map’s classification, however. A similar effect can be observed on the plateaus. In addition to the categorisation, the lower edge of the overburden is used as a basis here for confined areas, so the generally lower groundwater levels of May 2020 are often not visible in the Map “Depth to the Water Table”.