Abstract: Tidal creeks are important and distinctive features of coastal environments as they represent a basic circulatory system through which water,sediments,organic matter,nutrients and pollutants are transported into and out of intertidal wetlands. Based on the simplified Poisson hydrodynamic model,a procedure is compiled to achieve the watershed delineation for every subnetwork and drainage scaling properties extraction in the tidal basin of Upper Jiuduansha in Changjiang Estuary. To summarize the calculated and statistical results,two different evolution patterns are defined. The "concentration pattern" is characterized by a single,strong-developed network with alarger drainage area,developing under stronger hydrodynamic conditions,while the "scattering pattern" is represented by several small-scale networks and a smaller drainage area. In the two patterns,tidal channels stretch linearly with the increasing drainage area,which is consistent with the nearly same degree of channelization within the study area.