Hydrologic science: A distinct geoscience

Hydrologic science deals with the occurrence, distribution, circulation, and properties of water on Earth. It is clearly a multidisciplinary science, as through the hydrologic cycle water is important to and affected by physical, chemical, and biological processes within all the compartments of the Earth system: atmosphere, glaciers and ice sheets, solid earth, rivers, lakes, and oceans. Because of this geophysical ubiquity, and because water is necessary and limiting for life, concern for issues of hydrologic science has been distributed among the traditional geoscience and engineering disciplines. As a result, an infrastructure of hydrologic science (i.e., a clear identity, with supporting educational programs, research grant programs, and research institutions) has not developed, and a coherent understanding of water's role in the planetary‐scale behavior of the Earth system is missing. The supporting arguments, along with recommended scientific priorities are summarized here as proposed by the National Research Council Committee on Opportunities in the Hydrologic Sciences (see Table 1 for committee composition).