This Water Resources Thesaurus encompasses such broad research areas as the hydrologic cycle, supply of and demand for water, conservation and best use of available supplies of water, methods of increasing supplies, and the economic, legal, social, engineering, recreational, biological, geographical, ecological, and qualitative aspects of water resources. This volume represents a major revision of the previous edition of the Thesaurus, published in 1971. The principal source of terms for this edition has been the indexing used in Selected Water Resources Abstracts (SWRA). Since its inception in 1968, SWRA has indexed tens of thousands of publications. Its indexing terminology has been developed by expert abstracters and researchers, and represents the range of disciplines related to research, development, and management of water resources.