45 Hydrogeology (Posters)
Added due to amount of discipline abstracts submitted.
Wednesday, 11 March 2026
9:00 AM - 12:00 PM
RCC, Lower Level Hall
Water Quality Analysis of the Agricultural Plum Bayou Subwatershed within the Lower Arkansas-Maumelle HUC-8 Watershed
Paper number: 45-6
Program: Technical Sessions
Time: 9:00 AM – 9:00 AM
Authors
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Hannah Reyes Presenting AuthorSchool of Physical Sciences - Geology, University of Arkansas at Little Rock, Little Rock, Arkansas
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Adam WilsonSchool of Physical Sciences - Geology, University of Arkansas at Little Rock, Little Rock, Arkansas
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Kara PittsSchool of Physical Sciences - Geology, University of Arkansas at Little Rock, Little Rock, Arkansas
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Heather BlackSchool of Physical Sciences - Geology, University of Arkansas at Little Rock, Little Rock, Arkansas
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Michael DeAngelisSchool of Physical Sciences - Geology, University of Arkansas at Little Rock, Little Rock, Arkansas
Abstract
The Lower Arkansas-Maumelle HUC-8 watershed spans 1,100 square miles in an area that includes approximately 500,000 central Arkansans. A three-year water quality monitoring and sampling program to compare the forested Lake Maumelle subwatershed, the urban Fourche Creek subwatershed, and the agricultural Plum Bayou subwatersheds within this area was recently concluded. Here the focus is on the southernmost agricultural Plum Bayou subwatershed, but uses the Lake Maumelle subwatershed as a baseline for comparison since the Lake Maumelle subwatershed is a heavily-forested, drinking-water protected environment, while in contrast, the Plum Bayou subwatershed is characterized by extensive crop cultivation and pastures upstream of hardwood wetlands. Because of its agricultural setting, the Plum Bayou region is particularly vulnerable to nutrient pollution and sediment loading from farming practices.
Field parameter measurements and water samples were collected twice per month at four Plum Bayou subwatershed sites over the three-year project period. These parameters included temperature, turbidity, pH, specific conductance, and dissolved oxygen. The Arkansas Water Resources Center (AWRC) analyzed water samples for total nitrogen, ammonia-N, nitrate+nitrite-N, total phosphorus, soluble reactive phosphorus, total dissolved solids, and total suspended solids. This study presents time-series analyses of these parameters and analyses, focusing primarily on the potential relationship between nutrients and sediment concentrations and nearby agricultural practices. Statistical analyses include mean, median, and standard deviations taken for each parameter at all sites to establish baseline conditions, t-tests comparing nutrient and sediment load data between growing and non-growing seasons within Plum Bayou, and t-tests comparing Plum Bayou to the Maumelle subwatershed baseline.
Nutrient and sediment concentrations showed distinct seasonal patterns, with elevated phosphorus and nitrogen levels during the spring and summer. On average, Plum Bayou exhibited phosphorus concentrations nearly four times greater than the forested Maumelle headwaters during peak agricultural seasons. These elevated nutrient loads raise concerns for the potential eutrophication of wetlands that are critical to surface-water filtration. These results highlight the need for improved agricultural management practices that reduce seasonal nutrient loading toward the goal of protecting wetland ecosystem functions in the Plum Bayou region.
Geological Society of America Abstracts with Programs. Vol. 58, No. 1
doi: 10.1130/abs/2026SE-411736
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