3D numerical simulation of flow, sediment and mercury distribution in Enid Lake, Mississippi

Authors: CHAO, XIAOBO - University Of Mississippi; HOSSAIN, AZAD - University Of Tennessee; JIA, YAFEI - University Of Mississippi; CIZDZIEL, JAMES - University Of Mississippi

Submitted to: International Conference on Hydroscience and Engineering (ICHE)
Publication Type: Proceedings
Publication Acceptance Date: 3/20/2022
Publication Date: 5/26/2022
Citation: Chao, X., Hossain, A., Jia, Y., Cizdziel, J. 2022. 3D numerical simulation of flow, sediment and mercury distribution in Enid Lake, Mississippi. International Conference on Hydroscience and Engineering (ICHE). Vol. 14.

Interpretive Summary: A numerical model has been developed to predict the dynamic flow fields, and the temporal and spatial concentrations of sediment and mercury in the entire lake. Based on the upstream river flow discharge and suspended sediment concentration (SSC), outlet water surface elevation, and wind conditions, the flow fields, and the concentration of sediment in the lake can be solved. After obtaining flow information and SSC, the model can be applied to simulate the concentrations of total mercury (Hg) in the lake (water and sediment). The developed model was used to simulate a spring storm event and the modeling results of SSC and Hg concentration were generally in agreement with satellite imagery. Model results and satellite imagery show that the concentrations of SS and Hg were higher near the river mouth and shallow shoreline area than that in the deeper water areas near the dam. The model provides a useful tool to predict the mercury distributions of the entire lake.

Technical Abstract: Enid Lake is one of the largest reservoirs in the state of Mississippi. The soil in this region is highly erodible, resulting in a large amount of sediment discharged into the lake. Sediment is normally associated with many pollutants and greatly affect water quality and aquatic lives of the lake. It has been observed that Mercury concentrations in water, sediment and fish in Enid Lake are relatively high, and a fish consumption advisory has been issued by Mississippi Department of Environmental Quality since 1995. In this study, a 3D numerical model was developed to simulate the flow, sediment and mercury distributions in Enid Lake. Flow circulations in the lake are generally determined by the wind fields and the upstream river discharge. Sediment is normally introduced from upstream river flow. The total mercury in water and sediment were simulated, and the major processes, including advection, diffusion, adsorption/desorption, bed release, atmosphere deposition and settling were considered in the model. This model was applied to simulate a storm event and the simulated results were validated using remote sensing data. This model provides useful information to analyze the processes of fate and transport of mercury in natural lakes.