Container Terminal site for the three predominant wave directions, namely west, south-west and south. It was established that for efficient container handling operation the limiting wave height and peak spectral wave period are 0.5 m and 5 sec respectively.
Based on the above criteria the simulated results showed that in general, the proposed site is suitable for construction of container terminal and no significant interruptions to container handling operations due to wave disturbance is expected.
4.3 Tidal Current and Siltation Studies
A mathematical hydraulic model study involving hydrodynamic and sediment transport models was carried out under baseline conditions and with the incorporation of the proposed port development at Pasir Panjang off the south-west coast of Singapore. The primary objective of the study was to assess the impact of the proposed megaport development on the hydraulic and sedimentary regimes in the project area and the surrounding waters.
Field data relating to the bathymetry for setting up the regional and western models was supplied by the Port of Singapore Authority (PSA). Further data relating to tidal waterlevels and currents monitored off the south-west coast of Singapore during the period 8 August to 23 August, 1990 were available for validation of the hydrodynamic models. Analysis of seabed samples for particle size distributions and settling velocities of sediments were carried out for the Pasir Panjang site and surrounding waters. Further information relating to the average rate of siltation for the periods 1986-1987 and 1987-1988 was provided by PSA. The above field data formed the basis for validation of the hydrodynamic and sediment transport models.
The hydrodynamic simulations involved a suite of three models, namely regional model with a 1 km x 1 km grid, a nested western model with a grid size of 250 m x 250 m and a nested fine grid model with a resolution of 100 m x 100 m. Comparison between the computed and measured tidal water levels and currents over a 15-days period covering spring-neap tidal cycle at selected stations showed good agreement (Cheong et al, 1992).
The sediment transport model involved the application of a well-tested 2-D cohesive sediment transport model involving western model and fine grid nested model of Pasir Panjang region. The sediment transport model was calibrated for baseline conditions using available site specific data and best estimates of sediment parameters. Sediment transport simulations show that the sediment concentrations under spring tide conditions in the areas surrounding the proposed port development are in the order of 15-25 g/m The sedimentation rates within the proposed Pasir Panjang area varies upto 5 cm/yr and higher rates of the order of 10 cm/yr near the entrance. The average rate of siltation within the port development is estimated to be of the order of 3 cm/yr.
5. Conclusions
(a)Application of stable beach principle and using a series of shore-attached headland breakwaters for protection of newly reclaimed shoreline along the east coast of Singapore has provided an economical solution for the protection of the coast.
(b)Hydraulic modeling has provided an assessment of the impact of the Tuas reclamation on the hydraulic regime involving changes to current speeds and directions and current patterns in the west Johor Straits.
(c)The effect of the proposed development at Pasir Panjang on the hydraulic regime is confined to the project area and its vicinity. Sediment transport simulations have provided an average siltation rate of 3 cm/yr in the proposed harbour basin.
6. References
(1)Silvester, R., and Ho, S.K., "Use of crenulate shaped bays to stabilize coasts", Proc. 13th Inter. Conf. Coastal Eng., ASCE, 1973, p. 1347- 1365.
(2)Chew, S.Y., Wong, P.P., and Chin, K.K., "Beach development between headland breakwaters", Proc. 14th Inter. Conf. Coastal Eng., ASCE, 1974, p. 1399-1418.
(3)Jothi Shankar, N., Cheong, HF. and Chan, C.T., "A hybrid model for Singapore coastal waters", IES Journal, Singapore, Vol. 31, 1991, p. 81-95.
(4)Stelling, G.S., "On the construction of computational methods for shallow water flow
