IMPACTS OF URBANIZATION ON THE STONES RIVER WATERSHED: A CASE STUDY FROM MURFREESBORO, TN

Murfreesboro is one of the most rapidly urbanizing cities in the state of Tennessee, with a population increase of 40% from 2010 to 2020. As such, ecosystem health, water quality, and invasive species are of ever-growing concern within the Stones River watershed surrounding Murfreesboro.

The Stones River and other small water bodies within the watershed receive large amounts of urban and residential runoff and several of the smaller waterbodies, such as springs and wetlands, have been infested with invasive aquatic plant species, including parrot-feather or Myriophyllum aquaticum and alligator weed orAlternanthera philoxeroides. The springs and wetlands are connected through a groundwater system to each other and to the river and a study within these waterbodies in 2017 showed eutrophication and hypoxia with high ammonia and chlorine levels. Frequent continued monitoring of the Stones River watershed is necessary for the wellbeing of these connected ecosystems.

This project focuses upon eight locations within the watershed, including the springs and wetlands from the previous study, and additional locations from the East and West Forks of the Stones River. These locations include the East Fork up- and downstream of a major regional landfill that accepts 3,700 tons of waste daily from 34 counties across Tennessee. Due to its large size this landfill is of concern to the local community.

At each of the eight locations, we will collect water and sediment samples. Our water quality assessments will be conducted using a Hach test kit which analyzes the following parameters: temperature, pH, dissolved oxygen, ammonia, chlorine, nitrate, and phosphorous. We will analyze ecosystem health by using bioindicators, called testate amoebae, found within the sediment. These microscopic, unicellular protozoans are found in freshwater localities, produce a mineralized shell, and have been shown in numerous previous studies to respond to environmental changes. Initial results from the East Fork of the Stones River show the presence of both opportunistic species, such as Centropyxis aculeata, and species found in areas with high levels of organic content, such as Difflugia oblonga “tenuis.” Final results will include statistical analyses of populations from each location.