|Shields Jr, Fletcher|
Submitted to: Congress of International Association for Hydraulic Research Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 4/1/2009
Publication Date: 8/9/2009
Citation: Chao, X., Jia, Y., Shields Jr, F.D. 2009. Three-Dimensional Numerical Simulation of Flow and Pollutant Transport with Application to a Shallow, Natural Lake. Water Engineering for a Sustainable Environment. Proceedings, International Association for Hydraulic Research 33rd Congress, IAHR, Madrid, CD-ROM. Interpretive Summary: Lakes in agricultural watersheds sometimes have water quality problems due to polluted runoff from surrounding fields, and predicting water quality responses to conservation efforts is difficult due the complexity of in-lake processes. An existing computer model of water movement in lakes was modified to better represent wind-driven currents typical of a shallow lake. The modified model produced extremely accurate simulations of hypothetical situations and fairly accurate simulations of observed lake velocities and pollutant spreading. These findings provide a foundation for future lake water quality model development.
Technical Abstract: Presented is development and application of a three-dimensional numerical model to study wind-driven flow and associated pollutant transport in a shallow natural lake. A parabolic distribution of vertical eddy viscosity was specified to analyze the wind-driven flow. The model was verified against an analytical solution of wind-driven flow and validated using experimental measurements. The model was then used to simulate the wind-driven flow and pollutant transport in a shallow oxbow lake in the Mississippi River alluvial plain. Flow within the lake was primarily wind-induced. The flow velocities in the lake were measured using an acoustic Doppler current profiler. A slug of tracer dye was injected into an artificial runoff event into the lake, and the concentration distributions within the lake at selected times over two days were obtained. The simulated flow currents and dye concentration distributions in the lake were compared with field measurements, and good agreements were obtained.