Understanding Relations Between Streamflow, Turbidity, and Suspended-Sediment Concentration in an Impaired Mississippian Stream

Grafe, J., Ramirez-Avila, J. J., Schauwecker, T., Ortega-Achury, S. L., Prince Czarnecki, J. M., & Langendoen, E. (2018). Understanding Relations Between Streamflow, Turbidity, and Suspended-Sediment Concentration in an Impaired Mississippian Stream. Proceedings Mississippi Water Resources Research institute. Jackson, MS.

Abstract

Sediment is listed as the most common pollutant in rivers, streams, lakes and reservoirs in Mississippi and the USA. Understanding the relations between suspended sediment concentration and measurements of turbidity and their temporal and spatial variability can be used as tools for assessing the effectiveness of programs for reduction of nonpoint source pollution. The Red Bud-Catalpa Creek watershed in Mississippi is currently listed by the Mississippi Department of Environmental Quality (MDEQ) as impaired by sedimentation and a Total Maximum Daily Load (TMDL) has been developed that sets challenging targets for sediment load reductions. Water quality parameters including flow velocity and depth, turbidity, suspended sediment concentration (SSC), specific conductivity, salinity, temperature and pH have been weekly monitored in 40 stations along the main stream and three headwater tributaries of the Catalpa Creek in Mississippi. The study is part of a research oriented to determine spatial and temporal variations of SSC and suspended sediment loads and to determine the relations among streamflow, SSC and turbidity in the evaluated streams. Positive correlations were initially observed between turbidity and SSC for most of the monitoring sites, but initial results have evidenced that a single relation may not be used to determine SSC for the entire watershed. Results have also evidenced key locations along the stream where erosion is a main concern, and highlights areas where erosion control actions are imperative and for which further research should be conducted.