FEASIBILITY STUDY FOR A MAJOR CONTAINER TRANSHIPMENT HUB PORT AT COLOMBO

摘要

The geographical location of the Port of Colombo makes it a natural hub port for the transhipment of containers to and from the Indian sub-Continent and other parts of the region. In 2000, The Sri Lanka Ports Authority obtained assistance from the Asian Development Bank to study a major expansion of the port's container capacity. The study aims to increase the capacity of the port to about 10 million TEU/year, with the addition of 12 container berths in a new outer harbour. A numerical modelling programme was undertaken to study the effects of persistent southern swell and short period waves generated during the monsoon. A hydrodynamic model was used to study the coastal effects of the project. Geotechnical studies found that the dredged material would be suitable for the reclamation. The reclamation areas inside the breakwaters are effectively the "spoil ground" for the dredging. Separate borrow areas and dumping grounds are avoided with significant environmental advantages and cost savings. During 6 development stages, the basin and channel will be deepened in increments to obtain the necessary reclamation material. These increments will keep pace with developments in the size of mainline container ships. The final development comprises a breakwater and seawall of total length 5,600 m, enclosing an area of 700 hectares, made up of 250 hectares of reclamation and 450 hectares of sheltered water. The breakwaters and seawalls have a profound impact on the viability of the project. Therefore the engineering studies concentrated on minimising the unit cost of these items. The environmental impact of quarrying and transporting the necessary rock material was minimised by adopting caisson breakwaters in the deeper water and a rock breakwater near the shore. Rock for the breakwaters is planned to be transported from Galle in barges, so as to avoid transportation in trucks through the city of Colombo. Full height caissons with a sloping outer face were adopted for the deepwater portion and were found to be more economical, as well as having less environmental impact, than rock breakwaters. Baseline data for future environmental monitoring was collected and the environmental team maintained close liaison with the engineering team to ensure that the numerical modelling, both in the feasibility stage and planned for the implementation stage, will result in the minimum coastal impact and provide data for any necessary coastal protection works.