Based on the two important properties of the flow network database, it always can simulate water
flowing along the rivers. At each point at streams, we can determine from where all water flow come to
the point, and also to where water will flow from the point. This capability is important for pollution
tracing tasks for river environment simulation and controlling. It is possible to simulate potential
pollution resources when a monitoring station detected problem. It is also to predict where would be
possible effected by pollution resource dumped to a river at certain location.