Vulnerability of streams to legacy nitrate sources

Environmental Science & Technology
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Abstract

The influence of hydrogeologic setting on the susceptibility of streams to legacy nitrate was examined at seven study sites having a wide range of base flow index (BFI) values. BFI is the ratio of base flow to total streamflow volume. The portion of annual stream nitrate loads from base flow was strongly correlated with BFI. Furthermore, dissolved oxygen concentrations in streambed pore water were significantly higher in high BFI watersheds than in low BFI watersheds suggesting that geochemical conditions favor nitrate transport through the bed when BFI is high. Results from a groundwater-surface water interaction study at a high BFI watershed indicate that decades old nitrate-laden water is discharging to this stream. These findings indicate that high nitrate levels in this stream may be sustained for decades to come regardless of current practices. It is hypothesized that a first approximation of stream vulnerability to legacy nutrients may be made by geospatial analysis of watersheds with high nitrogen inputs and a strong connection to groundwater (e.g., high BFI).
Publication type Article
Publication Subtype Journal Article
Title Vulnerability of streams to legacy nitrate sources
Series title Environmental Science & Technology
DOI 10.1021/es305026x
Volume 47
Issue 8
Year Published 2013
Language English
Publisher ACS Publications (American Chemical Society)
Publisher location Washington, D.C.
Contributing office(s) California Water Science Center, Colorado Water Science Center, Kansas Water Science Center, Oregon Water Science Center, Wisconsin Water Science Center
Description 7 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Environmental Science and Technology
First page 3623
Last page 3629
Country United States
State Indiana;Maryl;Nebraska;North Carolina;Washington;Wisconsin
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