Europe has been experiencing a severe drought for years. Across the continent, groundwater levels have been consistently low since 2018, even if extreme weather events with flooding temporarily give a different picture.

Ground water in Central Europe in 2019 was already very low: photo courtesy Kvas - TU Graz  

Since a significant water shortage in Central Europe during the summer months of 2018 and 2019, there has been no significant rise in groundwater levels - levels have remained constantly low.

This has been confirmed by satellite data analysed by Torsten Mayer-Gürr and Andreas Kvas from the Institute of Geodesy at Graz University of Technology (TU Graz).

As part of the EU's Global Gravity-based Groundwater Product (G3P) project, they used satellite gravimetry to observe the world's groundwater resources and documented their changes in recent years.

Far-reaching consequences

The far-reaching consequences of the prolonged drought were evident in Europe in the summer of 2022. Dry riverbeds, stagnant waters that slowly disappeared and with them numerous impacts on nature and people. Not only did numerous aquatic species lose their habitat and dry soils cause many problems for agriculture, but the energy shortage in Europe also worsened as a result.

Nuclear power plants in France lacked the cooling water to generate enough electricity and hydroelectric power plants could not fulfil their function without sufficient water either.

Groundwater measurement from space

At the heart of the G3P project are twin satellites named Tom and Jerry, which orbit the Earth in a polar orbit at an altitude of just under 490 kilometres.

The two satellites at a flight speed of around 30,000 km/h. To carry out 15 Earth orbits a day, which means that they achieve complete coverage of the Earth's surface after one month. I

In cooperation with all other partners who contribute their data in the EU G3P project, Torsten Mayer-Gürr and his team provide the total mass, from which mass changes in the rivers and lakes are then subtracted, the soil moisture, snow and ice are also subtracted and finally only the groundwater remains.

The experts are located in Austria (Graz University of Technology, Vienna University of Technology, Earth Observation Data Center EODC), Germany (GeoForschungsZentrum GFZ in Potsdam), Switzerland (University of Bern, University of Zurich), France (Collection Localisation Satellites CLS, Laboratoire d'Etudes en Géophysique et Océanographie Spatiales LEGOS, Magellium), Spain (FutureWater), Finland (Finnish Meteorological Institute) and the Netherlands (International Groundwater Resources Assessment Centre IGRAC).

Europe has a water problem

The result of the cooperation shows that the water situation in Europe has now become very precarious – which Torsten Mayer-Gürr had not expected on such a big scale.

“A few years ago, I would never have imagined that water would be a problem here in Europe, especially in Germany or Austria. We are actually getting problems with the water supply here – we have to think about this,” he explains.

The European Space Agency ESA and its US counterpart NASA will continue this research with the MAGIC (Mass-change And Geoscience International Constellation) project. TU Graz will again be on board for the data evaluation.