The depth to the water table classes “2 to 4 meters,” “4 to 10 meters,” “10 to 20 meters” and “20 to 40 meters” each account for approx. 20% of the surface area. Groundwater-proximate areas with depths to groundwater < 2 meters make up approx. 12% of the area. Very high depths to groundwater > 40 meters occur only occasionally at morphological high sites, on approx. 1% of the area.
Within the glacial spillway, depths to groundwater are predominantly in the range of 2 to 4 meters below the surface. Groundwater-proximate areas with less than 2 meters’ distance from the groundwater to the top edge of the terrain are generally found in the neighborhood of a number of surface waters. Large areas with depths to groundwater of between 1 and 2 meters are also found in the southern villages of the Borough of Treptow-Köpenick (north and south of Langer See [“long lake”]) as well as in the Spandau Forest at Heiligensee east of the Havel, and also both to the north and to the south of Rummelsburg Bay.
Greater depths to groundwater (> 4 meters) have either morphological causes (e.g. the dunes in the Tegel Forest or in the Rehberge [“deer hills”]), or they are located in the intake areas of water-works wells (e.g. Spandau, Tegel, Friedrichshagen, Johannisthal), caused by the present lowering. In the glacial spillway, small areas can also be found with increased depths to groundwater, where confined groundwater conditions occur. Here, the groundwater depths are formed by the lower edges of the Vistula Moraine via Aquifer 2.
The depths to groundwater generally increase strongly in the plateau areas. Here, they are for the most part above 10 meters. The southern edge of the Barnim Plateau stands out particularly prominently. In the eastern area of the Barnim Plateau, depths to groundwater of less than 10 meters appear occasionally (e.g. in the area around Malchow Lake or in the headwaters of the Wuhle). Otherwise however, depths to groundwater of above 20 meters, some even in excess of 30-40 meters, are predominant here. The northern area of the Barnim Plateau – cut by the valley of the Panke, with the very low depths to the groundwater of the surface-proximate Aquifer 1 – is characterized by very high depths to groundwater of in some cases more than 50 meters. The ground moraine reaches a very great thickness here. Below the moraine formations (in places, the Vistula Moraine is directly on top of the Saale Ground Moraine), Aquifer 4 is in some cases even immediately present here. In the northwest, by contrast (Frohnau), the groundwater depths are mostly in the range of 20 to 30 meters, and, in the western areas, such as Bieselheide, often even less than 20 meters, where they are unconfined.
In the Grunewald Forest, as well as generally west of the Havel in Kladow and Gatow, there are extensive depths to groundwater of more than 20 meters. Here, the conditions are predominantly unconfined within the surface plateau sands; the high figures are caused by morphological elevations (the Teufelsberg [“devil’s hill”], the Schäferberg [“shepherd’s hill”], the Havel Hills at the Grunewald Tower), and also in the Müggel Hills.
The western area of the Teltow Plateau between the Grunewald chain of lakes and the Teltow Canal is characterized by strongly variegated depths to groundwater of between 5 and 30 meters. There are also differing regional conditions with respect to the confinement of the groundwater here. To the southeast of the Teltow Canal however, depths to groundwater are for the most part above 20 meters, with confined groundwater. This area is again subdivided by the valley of the Rudow Stream. To the east, in Bohnsdorf, there are once again depths to groundwater of more than 20 meters.
Compared with the depths to groundwater calculated in May 2002, considerably higher depths to groundwater are to be found only in the confined areas of the Barnim and Teltow Plateaus. These are areas which in May 2002 had been labeled as “unconfined” due to changed ground-water levels, and thus had a considerably higher potentiometric surface
Considerably lower depths to groundwater are, however, predominant in the unconfined areas, especially on the edges to the areas which were confined as of in May 2006. This effect is achieved by the current practice of separate calculation of the potentiometric surface in confined and unconfined areas (see above). This ensures that the calculation is not influenced by factors from outside the confined areas. This is e.g. particularly apparent to the south of the Teltow Canal in Adlershof, at the border of the Teltow Plateau, where currently, depths to groundwater of 1 to 2 meters pertain, while depths to groundwater of more than 4 meters were still calculated in 2002. The edges of the Barnim Plateau, e.g. east of the Wuhle or west of the Panke valley, also show this effect very clearly.
Apart from these methodologically dictated modifications, there are for the most part only insignificant deviations in comparison with May 2002, with differences which generally do not exceed one meter. Areas with greater depths to groundwater (up to 50 cm or even one meter), largely predominate, which is due to the slight drop in groundwater levels in May 2006, compared with May 2002, which was caused by climate-related factors.
There are however also areas in which the depth to groundwater has decreased by up to 50 cm or a meter. This is predominantly the case in inner-city areas in which the groundwater is exposed to other effects in addition to those caused by climatic influences. These effects may overlap, so that the depths to the water table in the unconfined areas of the glacial spillway remained relatively constant when comparing them over the course of these four years.