Beside the effect of gravitational forces, the water level in Sai Gon-Dong Nai River System is also affected by non gravitational forces such a wind, air pressure, rainfall and sea level rise. The purpose of this paper is to simulate the water level of these river based on the tidal and non-tidal constituents, from that assess the role of non-tidal constituents to water variation. In this study, the none-tidal data used includes the wind field at surface, sea level pressure and the rainfall in Sai Gon- Dong Nai Basin. With the analyzed data series from 1980 to 2007, the results show that after supplementing the non-tidal elements, the water level simulation quality is increased, the wind and rainfall have an important rote to water level. The results also show that near river mouths, the water level raised 13 cm from 1980-2007 due to the global climate change.
