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liter. Nitrite plus nitrate as nitrogen ranged from less than 0.1 milligram per liter at all sites to 0.53 milligram per liter at the most downstream site. Phosphorus con- centrations in 45 of 51 samples at all sites were equal to or less than 0.03 milligram per liter. Periodic increases in concentrations of nutrients at the two downstream sites were attributed to intermittent runoff from agri- cuIturallands, Concentration ranges for 22 trace constituents in the White River were determined. Concentrations of 15 trace constituents commonly were detected, and concentrations of 11 constituents generally were great- est downstream from Meeker. Suspended sediment could be an important source or transportation medium for eight trace constituents, The White River is an important and renewable source of good quality water in northwestern Colorado. Streamflow that originates as snowmelt in the North Fork and South Fork Basins dilutes and transports large concentrations of suspended sediment and dissolved solids that enter the White River in the central part of the basin. Some decrease in water quality occurs downstream from Meeker. INTRODUCTION The White Riveris a principal river in northwest- ern Colorado (fig. 1) and an important source of water in the Upper Colorado River Basin, Historically, water use and diversion within the White River Basin have been for agricultural and domestic needs. Constraints on water use generally were limited to years when basin runoff was small. However, during the national energy crisis in the 1970's and early 1980's, projected water needs in support of proposed oil-shale projects in the semiarid Piceance Basin caused an increase in fil- ings for water diversions from the White River. The potential losses of water from the White River from additional diversions and the increases in water-use demands in the Lower Colorado River Basin prompted concerns that the White River would become an over- allocated river and that water shortages would be com- mon. To meet projected local and downstream water needs, water managers reviewed and implemented plans to manage and store basin runoff. Kenney Reser- voir, with a storage capacity of 13,800 acre-ft, was completed on the White River about 8 mi upstream from Rangely (fig. 1) in late 1984. Several proposals for additional main-stem impoundments presently (1988) are being studied. Decisions related to the opti- mal location of each impoundment and the final approval of each proposal will require an understand- ing of the hydrologic characteristics .of the basin. Although some hydrologic data essential for effective water management of the White River are available, comprehensive data collections and data anl\lyses that describe and quantify sediment and water-quality characteristics with variations in stream discharge are incomplete. To address this need, the U.S. Geological Survey entered into a cooperative study in 1986 with the Yellow-Jacket Water Conser- vancy District to evaluate sediment and dissolved- solids transport and water-quality characteristics for the White River in northwestern Colorado. Water Users Association No.1, Rio Blanco County, and the Colorado River Water Conservation District provided some additional support for the study. Purpose and Scope This report presents an evaluation of selected hydrologic data for the White River collected during water years 1975-88. Specifically, the report: 1. Quantifies annual sediment loads and defines sediment-size characteristics that occurred at selected streamflow-gaging stations (herein- after referred to as sites) on the White River. The report relates changes in sediment charac- teristics in the White River with differences in basin hydrology and physiography and pro- vides estimates of volume displacement and capacity loss in reservoirs from sediment retention. 2. Quantifies dissolved-solids loads and describes changes in water-quality characteris- tics that occurred at selected sites on the White River. Water-quality changes are correlated with variations in stream discharge and spe- cific conductance, and differences in water quality are related to differences in basin phys- iography. Approach Water years 1975-88 (from October 1, 1974, to September 30, 1988) were selected for study because streamflow during the 14 years ranged from record highs to record lows, and the hydrologic conditions generally were representative of long-term hydrologic conditions for the basin. Periodic sediment and water- quality sampling also were begun in the mid-1970's at several sites on the White River and on the North Fork 2 Sediment Treneport end Water-QuaUly Characteristics and Loads, White River, Northwestern Coloredo, Water Vears 1975-88