Project Launch: The Groundwater Isotope Map of Germany

The overall objective of the new joint project with a total of nine partners from science, federal and state authorities and industry is to create for the first time a nation-wide interpolated isotope map (isoscape) of stable water isotopes and tritium concentrations in groundwater for Germany. The project start is scheduled for early 2023. The data will be made available to potential users in an interactive, long-term and expandable and adjustable manner. This is done from existing data of individual state offices, from literature, from companies as well as from new measurement campaigns within the project. The system will be expandable via historical data as well as future measurements after the end of the project. Signals of climate change, as they are already visible in the isotope ratios of precipitation, lysimeter seepage water and surface water, will be recorded for the first time with isotope data of the water of different compartments and can be systematically evaluated.

A first attempt to collect and measure groundwater isotopes values for a larger area was made 2015 during a groundwater sampling campaign in the state of Bavaria. A total of ~650 samples were analyzed for their δ¹⁸O and δ²H values. This data set gives the first state-wide overview of isotope values in groundwater for Bavaria. During the project the data set will be expanded to entire Germany. A joint European initiative on this tool for the sustainable use of water resources is a future vision of the project.