Isotope hydrology
Isotope hydrology is a field of geochemistry and hydrology that uses naturally occurring stable and radioactive isotopic techniques to evaluate the age and origins of surface and groundwater and the processes within the atmospheric hydrologic cycle. Isotope hydrology applications are highly diverse, and used for informing water-use policy, mapping aquifers, conserving water supplies, assessing sources of water pollution, investigating surface-groundwater interaction, refining groundwater flow models, and increasingly are used in eco-hydrology to study human impacts on all dimensions of the hydrological cycle and ecosystem services.