Modeling high sinuosity meanders in a small flume

Abstract

Meandering channels with exposed point bars and sinuosities near 2.0 can spontaneously develop in a mix of diatomaceous earth and kaolinite clay. The experimental streams that were studied were as small as 4 cm wide. They showed many of the characteristics found in large meandering streams such as migration of channels, formation of point bars, clay plugs, chutes and bar scrolls. Most of the meander series began as a first sharp bend that induced subsequent bends down stream. Sediment transport, specifically bed load, together with the slope of the floodplain, were the dominant influences, if not the cause of the channel instabilities that led to channel migration and bend formation. Bank cohesion allowed migrating channels to assume sinuous shapes and to maintain fairly uniform widths. The experiments were conducted in a small flume and used simple equipment. The use of light, fine grained materials in flume experiments may prove to be valuable in learning more about the conditions of soil, slope and flow which produce various meandering planforms.