Development of a two-dimensional analytical model for predicting toxic sediment plumes due to environmental dredging...

A two-dimensional analytical transport model is developed to predict the dredge induced plume concentration in the horizontal plane under steady-state for simple hydraulic conditions. The derivation of the analytical solution is based on the solution to the advection-diffusion equation. The application of this analytical model is limited to mechanical dredge operations, bucket dredge, which has continuous point source in the water column. The analytical model developed herein is used to simulate sediment concentration distributions from a hypothetical dredging site and compared to results from a similar model using Stokes' settling. The result shows that Stokes' settling underestimates settling in the near-field and overestimates settling in the far-field plume. In summary, the model provides the ability to account for the rapid settling of larger particles in the suspended sediment near the dredging operations while simulating the slower settling and diffusive transport of smaller particles moving away from the dredging sites.