The Science
Isotope hydrology utilizes the natural variance in the composition of water resources. During evaporation and condensation of water, the concentrations of oxygen and hydrogen isotopes change. As a result, in different parts of the hydrologic cycle, water is naturally tagged with isotopic fingerprints, which vary according to the history of a particular body of water and its route through the hydrologic cycle. There are other isotopes in rainwater, such as tritium and carbon-14, whose concentration decreases with time. These data enable experts in making evidence-based decisions on sustainable water resource management.