Abstract: Urbanization modifies river system, resulting in difficulties to divide watershed in urban areas. Based on water conservancy zones, a concept similar to watershed, this paper analyzed the effect of urbanization on river system evolution in Shanghai and the features of stream structure in accordance with some novel indicaters and a large number of local data from Shanghai Water Authority. Horton laws still play important roles in river system evolution in Shanghai. The regional physical characteristics was the base for river system growth. Because of urbanization influence, the ability of stream length development was weaker than the stream area development. Values of some traditional indicators were beyond the general scope, and river function indicators were closely related to structure indicators. The core indicators for describing the river system were the ratio of water area to whole area, the ratio of river cannel area to whole area, the mean ratio of river ramification, the mean ratio of stream length and the river channel storage and the adjustable river channel storage.

Key words: stream structure, river function, river system, urbanization, Shanghai City