WATER QUALITY CHANGES ALONG AN URBAN WATERSHED: COLEMAN CREEK IN LITTLE ROCK, AR

Coleman Creek runs from north to south in Little Rock, Arkansas for approximately 5 miles through industrial and residential areas. In this investigation, water samples were collected from select locations along the Coleman Creek watershed to better understand where pollutants might be entering the Coleman Creek, which flows into Fourche Creek, the largest urban wetlands in the south central region that eventually discharges into the Arkansas River. Water samples were collected from 6 different locations over a 9-month period along the creek and water parameters such as pH, salinity, conductivity, and temperature were measured. The samples were analyzed for cations, anions, trace metals, and alkalinity by ion chromatography, ICPMS, and titration. Field data, water chemistry, and the average stream metal concentrations in Coleman Creek were compared to EPA standards for drinking water and aquatic life. Results reveal that certain constituents increase as water flows from upstream to downstream (Na, Ca, SO₄, Cl, and B) in the watershed; while others exhibit the opposite behavior and decrease as the water flows downstream (Fe and Mn), which could be a function of dilution, adsorption, or pollutant addition. Selenium increased to concentrations higher than the EPA’s Continuous Criterion Concentration (CCC) of 5 ppb downstream of the first sampling location (15-34ppb) on several sampling events. Concentrations measured were compared to water levels and identified discharges in order to understand the creeks water chemistry changes. This research will help understand what potential problems low water creeks might have on aquatic life, human health, and water quality on a larger scale, as well as how a small stream’s water quality can change along its watershed and through time.