In April 1986, the U.S. Geological Survey began the National Water Quality Assessment Program, which at present (1987) is in a pilot phase in which assessment concepts and approaches are being tested and modified to prepare for full implementation of the program in the future. Seven pilot projects (four surface water projects and three groundwater projects) have been started. The preliminary plans for the surface water quality assessment of the Kentucky River basin pilot project are described. The Kentucky River basin drains an area of approximately 7,000 sq mi in east central Kentucky and is underlain by rocks that range in composition from limestone to sandstone and shale. Because greater than 95% of the basin population relies on surface water, surface water quality is of great concern. Land use practices that affect the surface water quality in the basin include agriculture, forestry, oil and gas production, coal mining, and urbanization. Water quality concerns resulting from the various land uses include the effects of: oil and gas field brine discharges; agricultural chemicals; sedimentation caused by coal mining; and trace element impacts from industrial and urban environments. Assessment activity is designed to occur over a 9-year period of time. During the first 3-year period of the cycle, concentrated data acquisition and interpretation will occur. For the next 6 years, sample collection will occur at a much lower level of intensity to document the occurrence of any gross changes in water quality. This 9-year cycle will then be repeated. Historical data will be evaluated to provide, to the extent possible, a description of existing and past trends in water quality conditions and to develop conceptual models that relate the observed conditions to the sources and causes, both natural and human-controlled. New data will be collected to verify the water quality conditions documented by historic data, to track long-term trends in water quality, to intensify temporal and spatial sampling densities, and to improve the understanding of the relations between water quality conditions and causative factors. (Lantz-PTT)