The U.S. Geological Survey operated hydrologic data collection stations during 1983 in response to the needs of all levels of Government for hydrologic information. Surface-water discharge was determined at 11,076 stations; stage data on streams, reservoirs, and lakes were recorded at 2,136 stations; and surface-water quality was determined at 4,610 stations. Ground-water levels were measured at 35,621 stations, and the quality of ground water was determined at 7,648 stations nationwide. Information on precipitation quantity was collected at 800 stations, and quality of precipitation was analyzed at 121 stations. Funding support for the hydrologic stations was derived either solely or from a combination of three major sources--the Geological Survey's Federal Program, the Federal-State Cooperative Program, and reimbursements from other Federal agencies.