Predicting redox conditions in groundwater at a regional scale

Environmental Science & Technology
By: , and 

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Abstract

Defining the oxic-suboxic interface is often critical for determining pathways for nitrate transport in groundwater and to streams at the local scale. Defining this interface on a regional scale is complicated by the spatial variability of reaction rates. The probability of oxic groundwater in the Chesapeake Bay watershed was predicted by relating dissolved O2 concentrations in groundwater samples to indicators of residence time and/or electron donor availability using logistic regression. Variables that describe surficial geology, position in the flow system, and soil drainage were important predictors of oxic water. The probability of encountering oxic groundwater at a 30 m depth and the depth to the bottom of the oxic layer were predicted for the Chesapeake Bay watershed. The influence of depth to the bottom of the oxic layer on stream nitrate concentrations and time lags (i.e., time period between land application of nitrogen and its effect on streams) are illustrated using model simulations for hypothetical basins. Regional maps of the probability of oxic groundwater should prove useful as indicators of groundwater susceptibility and stream susceptibility to contaminant sources derived from groundwater.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Predicting redox conditions in groundwater at a regional scale
Series title Environmental Science & Technology
DOI 10.1021/acs.est.5b01869
Volume 49
Issue 16
Year Published 2015
Language English
Publisher American Chemical Society
Contributing office(s) Oregon Water Science Center
Description 8 p.
First page 9657
Last page 9664
Country United States
State Maryland, New York, Pennsylvania, Virginia
Other Geospatial Chesapeake Bay watershed
Online Only (Y/N) N
Additional Online Files (Y/N) N