Abstract
We conducted three-dimensional numerical simulation to understand saline intrusion and fresh water dispersion in the Chikugo River estuary and the Ariake intertidal mudflat. The flow and salinity fields were computed in the area from the middle of the Ariake Bay to 23 km upstream of the Chikugo River during spring tides using a finite-volume hydrodynamic simulator with local mesh refinement technique. The simulated results were compared with the field data measured in Sept. 2002 for water level, salinity and velocity, and showed reasonable agreements with the measured data. The computed results were then used to investigate the effects of river-branches and Training Levee on the momentum and salinity transports. We found the transport of salinity and the river discharge redistribution are significantly affected by the asymmetricity of river branches and the thalweg topography in the intertidal madflat.
