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In late 1984, the U.S. Geological Survey, in cooperation with the Water Users Association No. 1 in the Colorado River Water Conservation District, began a reconnaissance of Kenney Reservoir. Because the study began when the reservoir was being filled, an opportunity existed to determine baseline water-quality conditions that can be used for future comparison. The reliability of estimating future water quality of the reservoir based on possible nonsteady-state conditions during the filling period was considered in the study. Although Kenney Reservoir is expected to have a fast flushing (flow-through) rate in late spring when streamflow in the White River is large, the hydraulic residence time will increase because of decreased inflow during late summer and fall and during low-flow years. During these periods of decreased inflow, the reservoir may develop thermal stratification and zones of decreased concentrations of dissolved oxygen. Related chemical and biological characteristics may change with depth and in bottom sediments, which may deleteriously affect reservoir uses. To evaluate these processes and changes and the effects of sediment transport to the reservoir, physical, chemical, and biological data were necessary to define seasonal variations in vertical and areal water-quality characteristics. The objectives of the study were to: (1) Describe the physical, chemical, and biological characteristics within the reservoir during the first 2 years after filling; (2) compare these water-quality characteristics with characteristics in the White River at a site about 8 mi upstream from the reservoir to determine effects of impoundment; and (3) describe the quantity and characteristics of fluvial-sediment movement in the White River upstream from the reservoir during 1983-87 and estimate the sediment retention of the reservoir during 1985-87. In 1987, the study and data collection were extended 1 additional year to document the water-quality effects in the reservoir from an unexpected phytoplankton bloom that occurred during the early summer of 1987. This extension also provided an opportunity to enhance the sediment data base for the White River with data collected in 1987, a low- runoff year compared with 1983-86. Purpose and Scope This report describes the physical, chemical, and biological character- istics of the water impounded in Kenney Reservoir and compares these water- quality characteristics to the inflow water from the White River. The report also describes the quantity and characteristics of fluvial-sediment movement in the White River upstream from the reservoir at site 3 during 1983-87 and presents estimates of the sediment retention in the reservoir during 1985-87. Three years of hydrologic data collected during 1985-87 from two sites in Kenney Reservoir are presented, and hydrologic data from one site on the White River about 8 mi upstream from the reservoir during 1985-87 are summarized. Site locations and general data-collection information are shown in figure 2 and are listed in table 1. 4