Water resources data for the 1971 water year for Michigan include records of data for the chemical and physical characteristics of surface and ground waters. Data on the quality of surface water (chemical, temperature, and sediment) were collected from designated sampling sites at predetermined intervals such as once-daily, weekly, monthly or less frequently, and at some sites data were recorded on punched paper tape at 60-minute intervals. Records are given for 371 sampling stations, of which 41 are continuous-record stations, 24 are partial-record stations, and 306 are miscellaneous sites. Records of chemical analyses also are given for 260 ground-water sites. Locations of surface-water quality stations are shown in Figures 3 and 4. The records were collected by the Water Resources Division of the U.S. Geological Survey under the direction of T. R. Cummings, district chief, and John J. Molloy, district chief, Water Resources Division, Columbus, Ohio. These data represent that portion of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Michigan.
The Geological Survey has published records of chemical quality, water temperatures, and sediment since 1941 in an annual series of water-supply papers entitled, "Quality of Surface Waters of the United States." Beginning with the 1964 water year, water-quality records have been released by the Geological Survey in annual reports on a State-boundary basis. These reports are for limited distribution and are designed primarily for rapid release of data shortly after the end of the water year. These records will be published later in Geological Survey water-supply papers.
