This publication presents and evaluates several isotope datasets compiled in a number of recently established river monitoring stations founded at the time of the creation of the Global Network of Isotopes in Rivers (GNIR). It also contains the preliminary results from 12 field sites now included in GNIR. These studies illustrate the different hydrological aspects of river basins that can be addressed by regular monitoring of environmental isotopes in rivers. The target readers for this publication are hydrologists, hydrogeologists and isotope experts dealing with catchment hydrology and management of water resources, as well as technical cooperation project counterparts in Member States.