The groundwater depths in the glacial spillway are for the most part approx. 2 to 4 meters below the surface. Groundwater-near areas with less than 2 meters depth to groundwater are generally located near those surface waters the shorelines of which have been used as support points for the calculation (e.g. the Erpe, the Panke and the Wuhle). Relatively large areas with groundwater depths of between 1 and 2 meters are located in the southern areas of the borough of Köpenick (north and south of the Langer See [“long lake”]), in the Spandau Forest, and north and south of the Rummelsburg Bay.
Within the glacial spillway, greater groundwater depths than about 5 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 work wells (e.g. Spandau, Tegel, Friedrichshagen). In the glacial spillway, small areas can also be found with increased groundwater depths, where confined groundwater conditions occur. Here, the groundwater depths are formed by the lower edges of the Vistula moraine.
The groundwater depths 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, groundwater depths of less than 10 meters appear occasionally (e.g. in the area around Malchow Lake or in the headwaters of the Wuhle). Otherwise however, groundwater depths of above 20 meters, or even above 30-40 meters, dominate here. The northern area of the Barnim Plateau – cut by the valley of the Panke, with the very low groundwater depths of surface-near Aquifer 1 – is characterized by very high groundwater depths of in some cases more than 50 meters. The ground moraine reaches 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 often even less than 20 meters in the unconfined areas.
South of the glacial spillway there are extensive groundwater depth areas of more than 20 meters in the Grunewald, as well as generally west of the Havel in Kladow and Gatow. There are predominantly unconfined conditions within the surface plateau sands; the high values are caused by morphological elevations (the Teufelsberg [“devil mountain”], the Schäferberg [shepherd’s mountain], 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 groundwater depths of between 5 and 30 meters. There are also differing regional conditions with respect to the conffinement of the groundwater here. To the southeast of the Teltow Canal, however, groundwater depths 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 groundwater depths of more than 20 meters.
In a comparison of groundwater depths of May 2002 with those of the last groundwater depth map of the Environmental Atlas of May 1995, current data indicate groundwater depths more than 10 meters higher. These are predominantly areas with confined groundwater in the Barnim and Teltow Plateaus, in which the groundwater depths have increased considerably due to the more detailed inclusion of the lower edges of the strata.
Within the glacial spillway, the groundwater depths are mostly around half a meter to one meter higher, in the current overview. This can be explained by climatic differences and also in some cases on the basis of progress-line observations of select measurement sites of the State Groundwater Service. By comparison of 2002 with 1995, there are areas with in some cases up to a meter or more lower groundwater depths, in the catchment areas of the well galleries of the waterworks (e.g. the Jungfernheide and Tegel WW, and single galleries of the Friedrichshagen WW) which have now been shut down or cut back strongly in their withdrawal levels.