Expected Highest Groundwater Level (EHGL)
You’d rather not experience water pushing up from the ground into the basement of your new house. In Berlin, however, many people live with this risk, as the groundwater lies only just below the surface. Planners and building owners therefore need to be aware of how high it may rise.
Groundwater levels have been recorded regularly throughout the entire city for many decades. These records demonstrate, for example, how humans have repeatedly caused water levels to fall and rise by building canals, underground railway shafts or consciously saving water in the past. Under the current conditions, however, the groundwater may rise a little higher than usual in future, depending on the weather.
For this reason, experts simulate the expected highest groundwater level (EHGL) using a mathematical groundwater flow model. For this purpose, they combine, for example, the increased rainfall with groundwater levels that have been measured in the past. They also consider how the rock layers are arranged below ground. However, they do not consider artificial interventions, for example, the extraction of groundwater in the production of drinking water at the waterworks or future construction measures in the area of hydraulic engineering along the river Spree.
Relevant numbers are currently available for about 90 % of the area of the State of Berlin. They comprise the following areas: the Berlin glacial valley, Panke valley, Teltow Plateau, Nauen Plate and Barnim Plateau. For construction measures, it is crucial to remember that ‘floating groundwater’ can sometimes occur above water-confining layers near the surface in the plateau areas.
Access the exact numbers and find out how they were determined in this topic.