T56 Urban Geochemistry (Posters)

Sunday, 9 October 2022
2:00 PM - 6:00 PM
Exhibit Hall F

IMPACT OF URBAN ACTIVITY AND WETLANDS ON WATER QUALITY IN FOURCHE CREEK, LITTLE ROCK, ARKANSAS

Paper number: T56-6
Program: Technical Sessions
Time: 2:00 PM – 6:00 PM

Authors

Abstract

Urban activity can alter and degrade water quality through point and nonpoint source pollution and human activities (traffic, mining, industry). Fourche Creek flows through urban Little Rock to the Arkansas River, and its wetlands provide many ecosystem services like flood control, habitat, and filtration. The overall purpose of this project was to better understand the impact urban areas have on Fourche Creek and the role of the wetlands in altering water quality. We selected four locations along the Fourche Creek Watershed and sampled during: Oct and Dec 2021, then Jan, Mar, July, and Aug 2022. We measured the following parameters at each location: turbidity, salinity, pH, conductivity, temperature, and dissolved oxygen. We collected and analyzed water samples from each site for cations and anions (by Ion Chromatography), trace elements (by ICPMS), and alkalinity (by acid titration). By using two USGS streamflow gages along the creek we were able to determine the stream discharge, water levels, and flow direction at the four locations. During several sampling events, the water flowed in from the Arkansas River to Fourche Creek, which impacted the F, Cl, Ca, and Mg concentrations in the creek. The amount of water within the creek varied with the highest water levels after storm events in Jan and Mar 2022, which diluted the concentrations of F, K, and alkalinity within the stream. The highest concentrations of Na and Cl occurred during March, despite having higher water levels, which indicated urban impact on the stream. During March we had colder temperatures and wintry precipitation, where road salt was put out and eventually washed into Fourche Creek. Rock Creek had the highest concentrations, which is likely related to the high amount of urban activity and nearby roadways in that region. Seasonal changes in temperature and precipitation impacted the wetland chemistry. The Arkansas River backflow, the stream discharge, human activity, and the wetlands played a role in the water quality within the Fourche Creek Watershed.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-380483

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