THE RANDOM COMPONENT IN STREAM MEANDERING¹

Abstract

An experimental investigation of the random component in stream meandering is described. The results of sixty replicate experiments of meander initiation and development made using the same discharge, bed material and bed slope are described and analyzed. It is demonstrated that the commencement of meandering is a random process. The random component in meander behavior is indicated by the size of the coefficients of variation of meander amplitude and wavelength of 0.45 and 0.22, respectively. A simple model is put forward to explain the observed deterministic and random components of meander behavior.

Influence of Valley Type on the Scaling Properties of River Planforms

“…Moreover, the wide range of scales typically used to calculate fractal dimensions by the divider method [e.g., Aviles et al, 1987;Hjelrnfelt, 1988;Tarboton et al, 1988;Snow, 1989;Rosso et al, 1991;Gan et al, 1992] The interplay of water flow, sediment transport, bed topography, and the nature of channel bank material controls meander development. Although some aspects of river planform geometry may reflect random processes [Langbein and Leopold, 1966;Thakur and Scheidegger, 1970;Ghosh and Scheidegger, 1971;Shreve, 1969Shreve, , 1974Ferguson, 1976;Wallis, 1978;Turcotte, 1992], the form and scale of meander patterns depend on interactions among channel gradient, valley floor material and the ratio of the river width to the valley width [Wolman and Leopold, 1957;Bagnold, 1960;Leopold and Wolman, 1960;Schumm, 1963;Ferguson, 1975;Hey, 1976;Davies and Tinker, 1984;Williams, 1986]. The form and size of meanders also depend on the river width-to-depth ratio, discharge, and the hydraulic properties of flow through bends [Dury, 1955[Dury, , 1969Einstein and Shen, 1964;Engelund and Skovgaard, 1973;Ferguson, 1975;Parker, 1976;Dietrich et al, 1979;Howard and Hemberger, 1991].…”