From Frankfurt to Basel, deep underground lies a treasure that supplies drinking water to more than five million people in the region. It is Europe’s largest groundwater reserve. It stretches for some 300 kilometres below the surface and feeds, among other things, the Upper Rhine and numerous wetlands.
But this vast groundwater reservoir is under severe strain, as a study published in June has shown. Pesticides, pharmaceutical residues and synthetic industrial chemicals known as per- and polyfluoroalkyl substances (PFAS) are polluting the groundwater; corresponding trace substances have been detected.
This underground basin of 150 billion cubic metres is not only vital for drinking water, it also influences countless animal and plant species. New discoveries are made again and again, such as the groundwater crayfish Parabathynella baden-wuerttembergensis. A journey beneath the surface between Germany, France and Switzerland.
Underground: the invisible river in the Rhine valley
The reservoir stretches from Frankfurt am Main across the French border to Strasbourg and further south to Basel in Switzerland. The volume of water is hard to grasp – 150 billion cubic metres is equivalent to around 60 million Olympic-size swimming pools.
