Characteristics of Turbidity Dispersion due to Disposal of Dredged Sediments into the Bottom of Stratified Water Column

Although backfilling of a dredged trench is an effective environmental restoration measure in many of bays, its efficient methodology has not been established so far. Thus, we considered an appropriate sediment disposal methodology to suppress dispersion of turbidity in the surrounding environment on the basis of experimental and numerical analyses. We adopted a tremie pipe, disposing sediments into the bottom of the trench, and considered the effects of the solvent and sediment densities, and the density of the lower water as well as the intensity of stratification. We clarified the characteristics of turbidity dispersion behaviors and found that a special care should be made when the density of the solvent lower than that of the bottom water in the trench, which might lead to rising and dispersion of turbid waters.