Comparing to the hydrographic map data, there will be two major accomplishments for this network
model. First, all stream elements will be properly connected topologically into network structure. The each
segments of river and stream need to be assigned a flow direction by adding an item to its attribute table [4].
All stream segments within one drainage basin will be linked as a tree. Tributaries drainage basin will be
branches of main stream drainage tree. Second, water flow direction of each stream element will be
building in as an attribution property of the elements. It is especially significant for any dynamic simulation
regarding water flowing in the river network. Based on the two characters, it is always possible to
determine water flow along rivers