Groundwater Levels of the Main Aquifer and Panke Valley Aquifer 2018
The present groundwater contour map describes the groundwater situation of the main aquifer with violet groundwater isolines and the Panke Valley aquifer in north-eastern Berlin with blue isolines. The interval between the groundwater isolines is 0.5 m. These show the potentiometric surface area of the unconfined and confined groundwater, respectively (see also Fig. 3). In areas of the main aquifer with confined groundwater, the groundwater contours are displayed in broken lines. In areas with no main groundwater aquifer, or with an isolated main groundwater aquifer of low thickness, no groundwater isolines are displayed. Those areas are shown with black dots.
The map is based on the topographical General Map of Berlin, scale of 1 : 50,000, in grid format, and the geological outline for the Berlin state territory, at a scale of 1 : 50,000, which was derived from the geological General Map of Berlin and Surrounding Areas, scale of 1 : 100,000. In addition, the used groundwater observation wells, as well as the individual waterworks are indicated, with their active wells and the water protection areas.
On the plateaus, the main aquifer is extensively covered by the glacial till and bolder clay (aquitards) of the ground moraines. Wherever the potentiometric surface of the main aquifer lies within such an aquitard, groundwater conditions are confined. In sandy segments above the till or in isolated sand lenses, near-surface groundwater may be formed, which is also called stratum water (see also Fig. 3). After extreme precipitation, it may rise to the surface. The groundwater levels of these locally highly differentiated areas have not been separately determined and portrayed.
In the Panke Valley, on the northern side of the spillway, the Barnim plateau, a major independent coherent aquifer has developed. It is located above the main aquifer, which is covered by the glacial till of the ground moraine (see also Figs. 7 & 8). On the present map, this aquifer is indicated by separate blue groundwater isolines. The glacial till is thinning out toward the Warsaw-Berlin glacial valley and the Panke Valley aquifer is interlocking with the main aquifer.
For more information, see the Groundwater Brochure:
www.berlin.de/sen/uvk/_assets/umwelt/wasser-und-geologie/publikationen-und-merkblaetter/grundwasser-broschuere.pdf (only in German)
Current Situation in May 2018
As a rule, the hydraulic gradient in Berlin, and hence, too, the flow direction, is from the Barnim and Teltow plateaus and the Nauen Plate toward the receiving bodies, the Spree and Havel Rivers. Depression cones have formed around the wells that were active during the measurement period, and have lowered the phreatic surface below the level of the neighbouring surface waters. Thus, in addition to inflowing groundwater from the shore side, the water pumped here also includes groundwater formed by infiltration (bank-filtered water) from these surface waters (see also Fig. 4c).
In May 2018, too, the potentiometric surface, which has been lowered in Berlin by drinking-water discharge over the past hundred years, was at a relatively high level compared to 1989 (Limberg et al. 2007: pp. 76 ff.). Areas in the glacial spillway in which the groundwater re-rose over this period of time by more than half a meter and by more than one meter, respectively, are shown on the difference map 1989-2012 (Fig. 10). Since 2012, the long-term mean of the groundwater level is stable in most parts of the city area.
The reduced raw-water discharge by the Berliner Wasserbetriebe since 1989 as a result of the decreased need for drinking and industrial water is responsible for the constant rise of the groundwater level. Moreover, five of the smaller Berlin waterworks (Altglienicke, Friedrichsfelde, Köpenick, Riemeisterfenn and Buch) were shut down altogether in the period from 1991 to 1997. In addition, drinking water production at the two waterworks Johannisthal and Jungfernheide has been discontinued temporarily since September 2001; at the latter, also artificial groundwater recharge was put on hold. However, under the immediate water management measures of the former Senate Department for Urban Development and the Environment, groundwater is still being discharged at the Johannisthal location in order to support current local waste disposal and construction measures. Likewise at the Jungfernheide location, groundwater was discharged by the Senate Department through the end of 2005. Since January 2006, a private company has performed the groundwater management there for continuing the dewatering of the cellars.
The water protection area of the waterworks of Buch, Jungfernheide and Altglienicke were abolished in April 2009.
The overall discharge of raw water by the Berliner Wasserbetriebe for public water supply dropped by almost half (42 %) in Berlin over a period of 28 years. In 1989, 378 million m3 were discharged, as opposed to 219 million m3 in 2002. In 2003, the discharge briefly increased slightly to 226 million m3 due to the extremely dry summer. After a further phase of decline until 2014, the discharge increased again in the past years to 217 million m3 at present and is at the same level as during the years of 2000 to 2006 (Fig. 11).
The development of the groundwater levels from May 2017 through May 2018 is exemplified at four groundwater observation wells which are largely unaffected by the withdrawal of water by the waterworks (Fig. 12).
The groundwater levels at the two observation wells (340 and 5139) in the unconfined aquifer of the glacial valley show a very fast and immediate reaction to the extreme precipitation events in the end of June and in the middle of July 2017. At the observation well 340 which is located at the outskirts of the city next to farmlands, the groundwater level rose from middle of July to beginning of October about around 1 m. The observation well 5139 which is located in the inner city area with a high soil sealing shows a less strong reaction to the described precipitation events (rise of around 0.2 m). From October 2017 on, the groundwater levels follow the annual longterm trend. Because of the very high total precipitation during the considered period, the groundwater level rose in the glacial valley about around 10 cm from May 2017 to May 2018 (Fig. 13 and Fig. 15).
For a contrast, the development of the groundwater levels of the covered confined aquifer on the Teltow plateau and on the Barnim plateau are shown by way of example on the observation wells 777 and 5004 in Fig. 14. The shape of the hydrograph of the groundwater level shows an atypical behavior that again can be explained by the extreme precipitation event of the high summer. Instead of a decrease of the groundwater level in summer, the water level is raising significally from end of June. Compared to the groundwater level in the glacial valley, the rise is lagging but more long-lasting. The decrease of the groundwater level in late summer is notable in the glacial valley, while shaped as a plateau between September and October in the area of the Teltow and the Barnim plateau. Afterwards, the groundwater levels are rising due to the seasonal nature. In May 2018, the groundwater level is about 1.2 m above the level of May 2017 on the Teltow plateau (Observation well 777) and 0.6 m above the level of May 2017 on the Barnim plateau (Observation well 5004).
In the period of June 2017 to May 2018, the precipitation amount at the climate station “Berlin-Tempelhof” with 795 mm was significantly higher than that of the long-term mean (1981-2010) with 577 mm. The high annual precipitation amount is due to the extreme precipitation events in June and July 2017. Also in October 2017, the monthly precipitation amount was higher than that of the long-term mean. In February, as contrast, low precipitation amounts were registered (Fig. 15).
Information on the expected highest groundwater level (EHGL), which is an important basis for planning the design of buildings, can be found in the Environmental Atlas under: /umweltatlas/en/water/groundwater-level-ehgl/2018/maps/artikel.962088.en.php (Limberg et al. 2015).