Capacity assessment of the recurrent disposal of dredged materials in a marine disposal area

Abstract

The capacity assessment of a marine disposal area can not only give full play to the role of the ocean in receiving dredged materials, but also provide a scientific basis for the management of the marine disposal area. This paper presents an assessment method for the capacity of a marine disposal area based on numerical models. The assessment is considered in terms of maintaining navigation security in the authorized marine disposal area and its nearby waterways and decreasing the effect of the suspended sediment concentration on the environmentally sensitive areas. To reproduce the dumping situation, a marine disposal area is discretized into tens or hundreds of point sources. The depositions in a marine disposal area and its nearby waterways are determined by the sediment transport model, which governs the transport of dredged sediment. The capacity of the marine disposal area is finally determined based on the navigable depth in the marine disposal area and its nearby waterways and the water quality requirement for the environmentally sensitive areas. A case study of Dongying marine disposal area in Laizhou Bay, China is presented. Numerical results indicate that to ensure safe navigation and to meet the water quality requirement for the environmentally sensitive areas, the annual capacity of Dongying marine disposal area can be up to 4.8 ×107 m3. The proposed assessment method can provide scientific basis for the selection and delimitation of marine disposal areas.