Abstract:
Numerical models composed of RMA2, RMA4, and SED2D program were used to simulate the circulation, salt and sediment dispersion in the Songkhla lagoon system during the year 2002. Important inputs to in the models were tidal data, river runoff, wind speed and direction, evaporation, precipitation and suspended sediment concentration. Models calibration involved comparison of the model results with measured current, salinity and suspended sediment data at 3 stations; namely Songkhla Channel, Kao Kaw, and Pak Raw, in the period of spring tide during 7-8 November 2002 and neap tide during 13-15 November 2002. Reasonable agreement was obtained between the model results and measured data. The results showed that current at the Songkhla lagoon system in wet season was influenced by river runoff and tide from the Gulf of Thailand and that during dry season was influenced by tide only. In the wet season, salinity intrusion was less than in the dry season. Sediment particles were less dispersed during dry season than during wet season and net sedimentation in Songkhla lake was more than in other area of the Songkhla lagoon system