Downstream alluvial aquifer, Konza Prairie LTER Site:
Blue line, upper part of
aquifer:
entrained nitrate trapped
in the unsaturated zone
increases nitrate
concentration
near the
water table when
water levels rise
groundwater NO3-N Green line, middle part of
concentration aquifer:
Red line, lower part of
aquifer:
receives dilute water
recharged from limestone
time ¨ bedrock that has low
nitrate and high sulfate
concentrations
GEMS: Geohydrologic Experimental and Monitoring Site, near Lawrence, Kansas, run by the Kansas Geological Survey, in Kansas River alluvium, near the bedrock-valley wall.
Nitrate concentration follows
hydraulic conductivity trends, with
sand-and-gravel portion of the aquifer
a conduit for transport of agricultural
nitrate. Some ports (4 and 7), are
ÒdragÓ points, where a thin layer of
low hydraulic conductivity material
results in slow change in nitrate
content compared to adjacent ports.
Nitrate concentrations vary on a
short-term basis, with changes
evident even when the sampling
interval is two weeks. Nitrate plume
is pulled toward a water-supply well
when local water demand is high,
resulting in the short-term variations
observed.
Refereed articles
Macpherson, G. L., 1998, Nitrate loading of shallow ground water, prairie vs. cultivated land, northeastern Kansas, USA: Proceedings, WRI-9 (Ninth International Water-Rock Interaction Conference, Taupo, New Zealand, 30 March-3 April, 1998), p. 165-168.
McElwee, C. D., J. J. Buter, Jr., G. L. Macpherson, G. C. Bohling, R. D. Miller, C. M. Mennicke, T. Huettl, M. Zenner, Z. Hyder, W. Lue, M. Orcutt, M. L. Beilfuss, M. L., and S. Gonuguntla, 1995, Characterization of heterogeneities controlling transport and fate of pollutants in unsonsolidated sand and gravel aquifers--Final report to the Dept. of Defense: Kans. Geol. Surv. Open-File Rept 95-16.
Macpherson, G. L., and M. K. Schulmeister, 1994, Source(s), fate and residence time of nitrate at two sites in Kansas--a comparison of carbonate and alluvial aquifers: Kansas Water Resources Research Institute Report, Contribution No. 312, 81 p.
Macpherson, G. L., 1993, Preliminary assessment of nitrate at two sites in Kansas--comparison of alluvial aquifer and fractured limestone: Kansas Water Resources Research Institute Report, Contribution No. 305, 39 p.
McElwee, C. D., J. J. Butler, Jr., G. L. Macpherson, G. C. Bohling, R. D. Miller, C. M. Mennicke, T. Heuttl, M.Zenner, Z. Hyder, W. Leu, and M. Orcutt, 1993, Characterization of heterogeneities controlling transport and fate of pollutants in unconsolidated sand and gravel aquifers: Second Year Report: Report to the U. S. Department of Defense, published as Kansas Geological Survey Open-file Report 93-21.
McElwee, C. D., J. J. Butler, Jr., G. L. Macpherson, G. C. Bohling, R. D. Miller, W. Leu, C. M. Mennicke, and Z. Hyder, 1992, Characterization of heterogeneities controlling transport and fate of pollutants in unconsolidated sand and gravel aquifers: First Year Report: Report to the U. S. Department of Defense, published as Kansas Geological Survey Open-file Report 92-20.
Hall, J. M., Macpherson, G. L., and Black, R. A., 1999, Nitrate in a Confined, Alluvial Aquifer: 3-D Movement Through Time: Geological Society of America, Abstracts with Programs, 31(6): p. A-396.
Macpherson, G. L., 1994, Source(s), fate, and residence time of nitrate in groundwater--A comparison of carbonate and alluvial aquifers: Water Research in Kansas, 1993, p.5.
Macpherson, G. L., 1993, Source(s), fate, and residence time of nitrate in groundwater--A comparison of carbonate and alluvial aquifers: Water Research in Kansas, 1992, p. 6.
Macpherson, G. L., C. D. McElwee, J. J. Butler, Jr., and G.
S. Bohling, 1996, Water chemistry variation in an alluvial aquifer--Multi-level
samplers reveal more than screened wells:
Geological Society of America, Abstracts with Programs, 28(7): p. A-460.
Schulmeister, M.
K. and G. L. Macpherson, 1996, Microscale variability in vertical, horizontal,
and temporal chemical gradients in an alluvial aquifer in Kansas: Geological Society of America,
North-Central Mtg., Abstracts with Programs, v.28, no. 6, p. 17
Macpherson, G. L., in press, Source(s), fate and residence
time of nitrate in groundwater, a comparison of carbonate and alluvial
aquifers: Water Research in
Kansas, 1994.
Macpherson, G. L., 1995, Redox zones and nitrate
reduction: 12th Annual Water in
the Future of Kansas Conference Proceedings, p. 27-28.
Schulmeister, M. K. and G. L. Macpherson, 1994, Spatial and
temporal variations in del-15-N --Preliminary evaluation of an alluvial aquifer
in Kansas, USA: GSA Abstracts with
Programs, 26(7): 323.
Macpherson, G. L., and M. K.Schulmeister, 1994, Nitrate in
typical Kansas aquifers: 11th
Annual Water and the Future of Kansas Conference, Proceedings, p. 24-25.
Schwab, A. P.,
C. W. Rice, W. Dodds, M. Sophocleous, M. K. Banks, J. K. Koelliker, and G. L.
Macpherson, 1994, NSF EPSCoR--
Biotic and abiotic factors controlling nitrogen flux in prisine and
agricultural subsurface systems:
11th Annual Water and the Future of Kansas Proceedings, p. 44.
Macpherson, G. L., 1994, Source(s), fate and residence time
of nitrate in groundwater, a comparison of carbonate and alluvial
aquifers: Water Research in
Kansas, 1993, p. 5.
Macpherson, G. L., 1993, Hydrogeology of the N4d watershed,
Konza Prairie Research Natural Area, Kansas: Fifth Annual Konza Prairie LTER Workshop, p. 27.
Schwab, A. P.,
C. W. Rice, W. K. Dodds, M. K. Banks, J. K. Koelliker, W. Macpherson, and M.
Sophocleous, 1993, NSF EPSCoR--Biotic and abiotic factors controlling nitrogen
flux in pristine and agricultural subsurface systems: Fifth Annual Konza Prairie LTER Workshop, p. 35.
Schulmeister, Marcia K., 2000, Hydrology and geochemistry of an alluvial aquifer near a floodplain margin: University of Kansas, unpublished Ph.D. dissertation, 132 pp. (supervisor, G. L. Macpherson)
McVay, Elizabeth , 2000, Geomicrobial denitrifying and nitrifying characteristics of a nitrate-contaminated alluvial aquifer, northeastern Kansas: University of Kansas, unpublished MS thesis, 116 pp. (supervisor, G. L. Macpherson)
Kidwell, Jessica Pursley, 1999, Nitrate distribution and reduction in a semi-confined alluvial aquifer; Geohydrologic Experimental and Monitoring Site (GEMS), Douglas County, Kansas: University of Kansas, unpublished MS thesis, 99 pp. (supervisor, G. L. Macpherson)
Hall, Jenney M., 1998, Nitrate in a confined, alluvial aquifer, Douglas County, Kansas: University of Kansas, unpublished MS thesis, 110 pp. (supervisor, G. L. Macpherson)