The present needs for international collaboration in the field of hydrology are discussed, primarily as they relate to water problems in international river basins. The scope and intensity of such collaboration have undergone considerable change during the past two decades. The responsibilities of the international inter-governmental organizations have also been in a state of flux, and the developments leading to the present organizational arrangements are described.
The role of the United Nations and the specialized agencies in water resources development are discussed as they pertain to the applications of hydrology. Several of the international scientific associations and unions are active in the field of hydrology and these also are considered.
1 Formerly Associate Director for Hydrology, National Weather Service, NOAA, Silver Spring, Md. The views expressed are those of the author and should not be interpreted otherwise.