Report Introduction: This study was intended to provide a compilation to expedite data-gathering phases of research and planning. The compilation was prepared as a reference for economists and others working in the field of water resources. Section I gives definitions of the more common terms found in water resource literature and other terms illustrating important physical relationships. Section II contains the major source materials that report the nationwide systematic inventory of water uses. Section III describes the data program for water supplies, and section IV summarizes projections made of future water uses and supplies. Each major source of data is described in some detail by type of data, period for which data are available, geographic breakdown, and completeness of coverage. Related references are given.