Jo. Helgesen et al., NITROGEN AND PHOSPHORUS IN WATER AS RELATED TO ENVIRONMENTAL SETTING IN NEBRASKA, Water resources bulletin, 30(5), 1994, pp. 809-822
Spatial distributions of nitrogen and phosphorus in water were related
to environmental setting as part of a regional water-quality assessme
nt of the Central Nebraska Basins. The environmental settings (Sandhil
ls, Loess Hills, Glaciated Area, and Platte Valley) were characterized
by different concentrations of nitrogen and phosphorus in ground wate
r and stream water. Statistically significant differences in nitrate c
oncentrations in both ground-water and stream-water samples were relat
ed to regional distributions of cropland and rangeland. Nitrate concen
trations were larger, especially in shallow ground water, in environme
ntal settings dominated by cropland and associated fertilizer use than
in settings dominated by rangeland. Similarly, total-nitrogen and nit
rate concentrations were relatively large in selected streams draining
primarily cropland. Comparative concentrations of phosphorus in strea
m water on the basis of environmental setting were similar to those of
nitrogen, although the largest phosphorus concentrations probably rel
ate to wastewater discharge into small streams. Nitrogen and phosphoru
s concentrations in much of the Platte River apparently reflected the
quality of water entering the study unit from upstream and limited bas
e-flow contributions from within the Platte Valley itself.