Conversely, during the southwest monsoon, May to October, most of the currents in western part of Andaman Sea go to east and south, therefore water masses will be gathering in Andaman Sea. This resulted in that sea water level increases in northern part of Malacca Strait, and the different of sea water level to South China Sea’s water level will be small, although in southern part of the Strait the sea water level is still higher. During this season, the water current in Malacca Strait flows to the north, with speed is little bit lower. Current velocity reaches to maximum in around July to August, with speed about 5 cm/sec. Oceanographic pattern is likely to affect the water quality and reef corals in the study sites. Strong wind during the wet monsoon period, for example, could cause water turbulence which affecting on high sediment, especially in coastal areas, and this might be worse with the high sediment run off from surrounding rivers and/or reclamation areas, such as happened in Batam. Water turbidity was recorded about 22 NTU during the wet season, and it is lower (about 7.4 NTU) in the dry season.