Numerical Simulation of Two-dimensional Pollutant Mixing in Rivers Using RAMS

The analysis of two-dimensional (2D) pollutant mixing is essential to implement the effective water quality management in natural streams. In this study, numerical simulations were performed to predict the 2D pollutant behavior, using the FEM-based river analysis software, RAMS. Pollution propagation was estimated by the 2D advection-dispersion model, CTM-2D. Velocity field was computed by the 2D shallow water model, HDM-2D. Dispersion coefficients are key input parameters in CTM-2D. To calibrate these parameters, tracer tests using Rhodamine-WT dye solution were conducted in the Sum River, Korea. The calibrated longitudinal dispersion coefficients from field studies showed values about 6 times larger than the theoretical from the Elder's equation (Fischer, 1967).