Spreading and Deposition of Turbidity Currents: Application to Open-Water Sediment Disposal

Abstract

A new two-phase box model is developed in this study for the prediction of a spatially varying turbidity current with sediments on a horizontal bottom. The turbidity current is segmented into small subvolumes to account for the spatial variation with nonuniform spreading, while a two-phase formulation computes the differential settling of the suspended sediments inside the turbidity current, which form deposits onto the seabed. In addition, the new model is capable of simulating the transition from constant flux to fixed volume propagation, which is typical for both natural submarine landslides and engineered barged sediment disposal. The computation is terminated when most of the total sediment volume is deposited, yielding the final deposition pattern. Following the model development, a detailed experimental study was carried out in the laboratory to validate the model predictions by releasing large but finite amounts of sediments through a rectangular opening on the water surface. The agreement between the model predictions and experimental measurements was found to be satisfactory. Finally, this model is integrated into the Barged Sediments Disposal Model (BSDM) software for the assessment of open-water barged sediment disposal. A practical application of the integrated BSDM is demonstrated using a field study reported in the literature.