HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text Free Full Text (PDF) Free Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (32) Citing Articles via Google Scholar Google Scholar Articles by Puckett, L. J. Articles by Cowdery, T. K. Search for Related Content PubMed PubMed Citation Articles by Puckett, L. J. Articles by Cowdery, T. K. GeoRef GeoRef Citation Agricola Articles by Puckett, L. J. Articles by Cowdery, T. K. Related Collections Nitrogen Water Pollution Ground Water Quality

Transport and Fate of Nitrate in a Glacial Outwash Aquifer in Relation to Ground Water Age, Land Use Practices, and Redox Processes

^a U.S. Geological Survey, 413 National Center, Reston, VA 20192
^b U.S. Geological Survey, 2280 Woodale Road, Mounds View, MN 55112

View larger version (45K): [in a new window]   Fig. 1. Location of the study area north of the Otter Tail River.

View larger version (16K): [in a new window]   Fig. 2. (a) Annual fertilizer N applications in Otter Tail county since 1945; (b) cumulative N applications during the same period.

View larger version (33K): [in a new window]   Fig. 3. Cross-section of the study transect showing land use, piezometer nest locations, screened intervals, stratigraphy, and approximate locations of MODFLOW layers.

View larger version (31K): [in a new window]   Fig. 4. Ground water flow lines and travel times along the study transect based on the MODFLOW/MODPATH simulation.

View larger version (31K): [in a new window]   Fig. 5. Apparent ground water recharge dates as determined from chlorofluorocarbon (CFC) concentrations measured in ground water samples and generalized age distribution along the transect based on the MODFLOW/MODPATH simulation.

View larger version (15K): [in a new window]   Fig. 6. Argon and N2 gas concentrations for samples collected during 1994, 1995, and 1997 and their theoretical values. Values to the right of the air-saturated water equilibrium line represent excess nitrogen concentrations. Horizontal tick marks on the equilibrium line indicate Ar and N2 equilibrium concentrations from 0 to 20°C in 2° increments.

View larger version (27K): [in a new window]   Fig. 7. Distribution of excess N2 along the transect.

View larger version (26K): [in a new window]   Fig. 8. Concentrations of NO-3 along the transect.

View larger version (53K): [in a new window]   Fig. 9. Distibution of (a) Cl- and (b) SO2-4 along the transect.

View larger version (40K): [in a new window]   Fig. 10. The generalized redox state of the aquifer along the transect.

View larger version (27K): [in a new window]   Fig. 11. Distribution of reconstructed (original) concentrations of NO-3 calculated as the sum of excess N2 and NO-3 measured along the transect.