CENTRAL NEBRASKA RIVER BASINS, NEBRASKA¹

Abstract

: The Central Nebraska Basins (NAWQA) study unit includes the Platte River and two major tributaries, the Loup and Elkhorn Rivers. Platte River flows are variable in the western part of the study unit because of diversions, but the Loup and Elkhorn Rivers originate in an area of dune sand covered by grassland that generates consistent base flows. More frequent runoff in the eastern part of the study unit also sustains stream flow. Ground water in the study unit has no regional confining units and the system is a water table aquifer throughout. Macroinvertebrate and fish taxa at biological sampling sites in the state were related to stream flow. One of the four wetland complexes identified in the study unit includes habitat for threatened and endangered bird species. The study unit is an agricultural area that includes row crops, both irrigated and nonirrigated in the eastern and southern parts, and rangeland in the Sand Hills of the western part. A water quality assessment will be based on the differences in environmental setting in each of four subunits within the study unit.]

Response of algal metrics to nutrients and physical factors and identification of nutrient thresholds in agricultural streams

“…Platte River stream flow is controlled by reservoir operations on the North Platte River in Wyoming and Lake McConaughy (since 1941) near the mouth of the North Platte River. The South Platte River in Nebraska is influenced primarily by irrigation return flows at low flows (Huntzinger and Ellis 1993). The remaining 17 sites were located throughout the western United States and were characterized by very low levels (<10%) of agriculture and/or urbanization.…”

Water quality in the central Nebraska basins, Nebraska, 1992-95

“…The Central Nebraska Basins Study Unit includes about 30,000 mi 2 (square miles) of the Platte River Basin from the confluence of the North and South Platte Rivers near North Platte, Nebraska, to its mouth near Omaha, Nebraska [1]. The environmental settings of the Central Nebraska Basins are characterized by differences in soils, precipitation, and land use and are divided into the Sandhills, Loess Hills, Glaciated Area, and Platte Valley subunits.…”

“…1 Nitrate, as used in this report, was analyzed as nitrite plus nitrate and concentrations were reported as total nitrogen.…”

Shallow ground-water quality in the Platte River Valley alluvium, Nebraska, October-November 1997

“…An important hydrologic process in the Platte River Valley is surfacewater/ground-water interaction (Huntzinger and Ellis, 1993). Ground water in the alluvial deposits has a direct hydraulic connection with the Platte River Verstraeten and others, 1999); thus, ground-water gradients and water quality are affected by flows in the river ( fig.…”