Entropy and river meander planform

Abstract

This study departs from the hypothesis that the often striifing geometric similarity and regularity of meanders is the result of the second law of thermodynamics applied to open dissipative systems. It is argued that along a meandering river the continuous production of entropy is as low and as uniform as possible. An expression of entropy production in a moderately meandering river is derived. A dimensioniess form of Odgaard's Meander flow model (1986a) is used to evaluate this expression along different meander bends described by the class of third order sine-generated curves. The results show a minimum variance of entropy production for a fattened curve with upvalley skewing, indicating that meander asymmetry described by Carson and Lapointe (1983) is in correspondence with the Theory of minimum variance (Langbein and Leopold, 1966).