Numerical Simulation of Sewage Transport-Diffusion in Xiyang Channel on the Radial Sand Ridges of South Yellow Sea

Based on the 2-D numerical model averaged in vertical direction which was performed for the tidal current and pollutant diffusion in the Xiyang channel along the southwestern coast of the Yellow Sea, the influence of pollutant diffusion at the effluent discharge sites which are located at water depth 5 m, 7 m and 10 m (under the theory of datum) respectively during spring tide were calculated and analyzed. The results show that the sewage will soon be diluted after discharged into the sea. The envelope areas for both 500 and 200 dilutability contour isoline are small. And obviously, the envelope increment is inversely proportional to the water depth. Based on the model, the envelope areas under different discharge for both 500 and 200 dilutablity contour isoline are calculated, finding the two variables have a positive relationship in series of power.