STABLE WIDTH OF AN ALLUVIAL CHANNEL

Alluvial channels, in the context of this paper, are unlined man-made channels with predetermined bed slopes used to convey water that carri es sediment. An extremal hypothesis is presented, namely, an alluvial channel attains a stable width when the rate of change of unit stream power with respect to its width is a minimum. An easy-to-use width con trol parameter is presented and compared with a form of Lacey's silt f actor. The hypothesis is tested on data from canals located in the Pun jab and Sind provinces of Pakistan.