Groundwater Levels of the Main Aquifer and Panke Valley Aquifer 2018
The basic data that is needed for the preparation of the groundwater contour map is provided by the State Geology workgroup of the Senate Department for the Environment, Transport and Climate Protection, by the Berlin Waterworks [Berliner Wasserbetriebe] and by the federal state of Brandenburg.
The first regular recording of groundwater levels was initiated in Berlin as early as 1869, at 27 groundwater measurement points (Fig. 9).
The Berlin groundwater monitoring network grew rapidly. By 1937, there were already more than 2000 observation wells. After an optimization of the monitoring network in the city area, the State Geology workgroup operates approx. 1,000 observation wells that are installed in five different aquifers.
In the inner-city area too, which is not within the area affected by the waterworks, groundwater conditions have been influenced strongly by anthropogenic processes for over 100 years now. This can be shown by way of the example of the hydrographic curve of groundwater level at the observation well 5140 (Fig. 9) in the borough of Mitte, as following:
Until 1890, the largely natural seasonal fluctuations of the groundwater level remained apparent. With the growth of the city, increased impervious coverage, and the construction of small wells for drinking water, the amplitude was reduced, and the groundwater level had, by 1905, been moderately lowered. Thereafter, the large water retention operations connected with major construction sites, e.g. for the underground/ subway and the urban rail lines (S-Bahn), for the construction of the Reichsbank (today, the Foreign Ministry) and for bunkers, etc., with their deep cellars reduced the level of the groundwater by another 10 m over a large area. In 1945, at the time of the collapse of the infrastructure after the Second World War, the groundwater level quickly rose back almost to its original level. During the years of reconstruction, it was then repeatedly lowered again. Since the termination of major construction projects with groundwater retention, the groundwater is now back to a high level, and major precipitation events rapidly lead to a short-term rise in the level. Here, as in other areas of the city, in buildings which have not been sealed against the maximum expected groundwater levels this causes damage from penetrating groundwater.
The groundwater observation wells are now equipped with automatic data loggers, and provide daily measurements. The data base now contains more than 10 million measured values. Several data loggers in selected observation wells transmit data to the database via radio, so that they are available online. in the Berlin Geoportal in the map display “Groundwater level – measurements and hydrographic lines updated daily” [available in German only].
In addition, the Berliner Wasserbetriebe and the Brandenburg State Environmental Agency as well as other waterworks operators in Brandenburg provide groundwater level measurement data for the Berlin area and the surrounding areas with an at least monthly measurement frequency. If the groundwater has a direct connection to surface water (effluent situation, Fig. 4a), additional level data from surface-water measurement points are used.
For the present map, the water level data of 1866 groundwater observation wells within Berlin, of 337 groundwater observation wells from Brandenburg and of 47 surface-water measurement points is used for the main aquifer (Aquifer 2). For the groundwater level map of the Panke Valley aquifer (Aquifer 1) on the Barnim plateau, the water level data of 80 groundwater observation wells and 13 surface-water measurement points is used. In groundwater observation wells with daily measurements, the value of May 15th, 2018 was used, while for the other cases, the value was taken from the day that was closest to May 15th, 2018.
The distribution of the groundwater observation wells is irregular: The monitoring network is densest in the city centre and in the immediate intake areas of the water-works, and less dense at the outskirts of the city, especially in the surrounding areas in Brandenburg.