International Hydrological Decade, research program on water problems that began on Jan. 1, 1965, following a resolution unanimously adopted by the 13th session of the General Conference of the United Nations Educational, Scientific and Cultural Organization (unesco) in November 1964. National Decade committees were set up to coordinate national programs and to maintain liaison at the international level; to provide overall direction, the Unesco General Conference established a coordinating council.
The scientific program of the Decade embraced all aspects of hydrology and took into account the great diversity in the quality and quantity of hydrologic information available in various countries. The acquisition of correct basic data over a sufficient time period became of paramount importance in preparing development projects of widely different kinds. From the first years of the Decade many important results were obtained. National committees were created in 96 countries bringing together, in many cases for the first time, representatives of different national organizations dealing with water problems. The Decade Council created 10 working groups and 4 panels to coordinate at an international level the implementation of specific parts of the program.