Three-dimensional model of conservative pollutant migration and its application in the Dalian Bay

Based on an unstructured grid,finite-volume coastal ocean model and coupled the Lagrangian particle tracking model and the conservative pollutant transport diffusion model,the hydrodynamic change,the tidal-induced residual current,the conservative pollutant transport,the trajectories of characteristic particles and different artificial islands influence on conservative pollutant transport were simulated.It was verified that the results of the ocean model agreed well with the field observed data.The results showed that tidal-induced residual current presented the form of clockwise semi-vortex flow;the direction of residual current in the bay estuary was NE,and the direction of conservative pollutant migration was the same as the residual current direction;the self-purification capacity of conservative pollutants in the bay estuary was better than that in the bottom,and such capacity in the northern bay was better than that in the southern bay;the pollutant in the sub bays was difficult to diffuse out.Both of artificial island scenarios would reduce the self-purification capacity of the Xiangshuitao Bay and the Choushuitao Bay,and the impact of scenario 2 was greater than that of scenario 1;the artificial island 1 would also reduce the self-purification capacity of the Hongtuduizi Bay,but scenario 2 would improve its water quality.