ABSTRACT
Hillslopes and channels are the constituent elements of the drainage basin. Occurring in a hierarchy of sizes, the drainage basin is typically a welldefined topographic and hydrologic entity which is regarded as a fundamental spatial unit (Chorley, 1969). While the links between hillslopes and channels in the movement of water and material through the drainage basin should be recognized at the outset, the channel network itself is the initial focus here, firstly as regards its properties, and secondly as regards its possible mode of evolution. The first can be determined from the analysis of existing networks but the second can rarely be observed directly, and explanations of evolutionary tendencies often depend on the results of network analyses.
