simulation of Transport of BOD at the Han River Using 2-D Advection Dispersion Model

In Korean rivers, pollution sources coexist with water intake facilities at the same reach. Therefore it is essential to develop a model that can predict the two-dimensional behavior of pollutant mixing. In this study, finite element model with Galerkin method was adopted to the 2-D depth-averaged advection-dispersion equation of reactive pollutants to analyze the transport of BOD. Comparison between analytic and numerical solution which was performed in rectangular channel to verify the developed model showed that the shapes of pollutant cloud are well matched. The model was applied to the field region ranging from downstream of Pal-dang dam to Cham-sil submerged weir, which is 15.8 km in length and water quality was examined at Am-sa and Gu-ui water intake facilities. When treated water in Gu-ri sewage treatment plant flows from Wang-suk stream into Han River, the numerical results of BOD concentration in Am-sa and Gu-ui water intake facility was very close to the measured values conducted by Ministry of Environment during that period. To investigate the influence of location of pollutant injection on the water quality at water intake facilities, instantaneous injections were made at left, center and right side of Kang-dong bridge. The result showed that in case of left injection, Am-sa and Gu-ui water intake facilities were influenced significantly by the injection. However, center and right injection did not affect much Am-sa water intake facility located in left side of the river.