NUTRIENT
LEVELS REMAIN UNCHANGED IN TRINITY RIVER BASIN STREAMS AND GROUND WATER
(Map Area 34)
Water-quality trends were evaluated for about 4,800 samples from
streams and 1,500 samples from wells. Concentrations of total nitrogen
and phosphorous have not changed significantly from 1974 to 1991 at most
sites, although there was a decrease in phosphorous concentrations near
Dallas. Spatial variations in chemical concentrations in streams are
related primarily to point sources and reservoirs. The largest nutrient
concentrations occur downstream from Dallas, where streamflow is dominated
by treated
wastewater. The smallest concentrations occur just downstream from
reservoirs, which act as sinks for nutrients. The largest concentrations
of nitrate in ground water have been detected in samples from the Queen
City and Nacatoch aquifers. Concentrations tend to decrease with
depth.
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Last modified: Tue Oct 31 15:36:15 1995