https://doi.org/10.1038/s41561-020-0629-7

Ferguson, G., Cuthbert, M. O., Befus, K., Gleeson, T., & McIntosh, J. C. (2020). Rethinking groundwater age. Nature Geoscience, 13(9), 592-594. https://doi.org/10.1038/s41561-020-0629-7

It is commonly thought that old groundwater cannot be pumped sustainably, and that recently recharged groundwater is inherently sustainable. We argue that both old and young groundwaters can be used in physically sustainable or unsustainable ways.

The idea that old or ‘fossil’ groundwater with long residence times is a non-renewable resource is found in scientific literature about groundwater sustainability1,2,3,4 and in media coverage of groundwater issues on a regional to global scale. However, we argue that groundwater residence times and ages are not metrics that can directly define groundwater sustainability. Instead, quantifying the distribution of groundwater ages in an aquifer can improve our understanding of aquifer systems and in turn indirectly inform sustainable groundwater use. Dispelling the myth that groundwater sustainability depends on its age is important for tackling groundwater depletion problems around the world5. Here we discuss what groundwater age and residence time can and cannot tell us about the functioning of past and present groundwater systems, and their sustainability.

Old Meets New

https://doi.org/10.1038/s41561-020-0629-7