Date of this Version
Zelt, R.B., and P.R. Jordan, 1993. Water-Quality Assessment of the Central Nebraska Basins: Summary of Data for Recent Conditions Through 1990. U.S. GEOLOGICAL SURVEY Open-File Report 93-422. Lincoln, Nebraska
Among the first activities undertaken in each National Water-Quality Assessment (NAWQA) investigation are the compilation, screening, and statistical summary of available data concerning recent water-quality conditions in the study unit. The water-quality conditions of interest in addressing the objectives of the NAWQA program are those that are representative of the general water quality of a given stream reach or area of an aquifer. This report (1) identifies which existing water-quality data are suitable for characterizing general conditions in a nationally consistent manner and (2) describes, to the extent possible, recent, general water-quality conditions in the Central Nebraska Basins. The study unit consists of the area drained by the Platte River between the confluence of the North Platte and South Platte Rivers near North Platte downstream to its confluence with the Missouri River south of Omaha. The report includes (1) a description of the sources and characteristics of the water-quality data that are available, (2) a description of the approach used for screening data to identify a subset of the data suitable for summary and comparisons, (3) a presentation of statistical and graphical summaries of recent, general waterquality conditions, and (4) comparisons of recent, general water-quality conditions to established national water-quality criteria, where applicable. Stream- and lake-water data are summarized for 25 selected stream-water and 11 lake-water sampling sites. Data also are summarized by major subunits of the study unit (the Sandhills, Loess Hills, Glaciated Area, and Platte Valley subunits) for streambed-sediment, fish-tissue, aquatic-ecological, and ground-water samples. The summaries focus on the central tendencies and typical variation in the data and use nonparametric statistics such as frequencies and percentile values.