Abstract
The objective of this paper is to show a theoretical approach to the determination of optimal order of channel routing within a channel network. The channel network with tree structure, widely used in distributed hydrological modelling, is studied. In addition to tree structure, the structure of drainage system which indicates the relation of upstream subnetworks is used to represent its logical structure. Under the basic rules of channel routing, namely from upstream to downstream, the theory about optimal order of channel routing is established, and an algorithm to obtain this order automatically is developed by considering the logical structure of channel network. The result shows that for a channel network with Horton-Strahler order ω, necessary and enough number of buffers storing series of discharge is only ω.
