Modeling of most efficient channel form: a quantitative approach

Abstract

A fundamental index of channel shape is the form ratio (w/d) which is determined by energy-load relation and bank and bed materials of the channel concerned. Average river channels tend to develop their channel-cross sectional form in a way to produce an approximate equilibrium between the channel and the water and sediment it transport. But how far it is deviated from the ideal cross-sectional form is determined only by knowing the ideal form which was calculated ‘2’ by Hickin (2004) for rectangular channel. This ideal cross-sectional form of ‘maximum efficiency’ is virtually a theoretical one and by attaining of which a river transports its water and load with least friction with its bed. But ideal form ratios for triangular and semicircular channels have not been calculated earlier. Present paper has found out ideal form ratios 2.544 and 2.31 for semicircular and triangular channels respectively.