The U.S. Geological Survey is conducting a multidisciplinary, 7-year study of the Charlotte Harbor estuarine system in southwest Florida. A large part of the study is devoted to the collection, analysis, and interpretation of water quality data, including physical, chemical, and biological characteristics. This report presents the water quality and bottom sediment data collected during the first 2 years of sample collection, November 1982 through October 1984. The variables measured include nutrients, major ions, trace metals, radiochemicals, pesticides and other organic compounds, chlorophyll, temperature , oxygen, specific conductance, water transparency, and sediment grain size analysis. The report also outlines the methods of data collection and analysis and provides information on sample locations and frequency of sampling. (USGS)