Abstract: River bends are the most significant geomorphologic unit of meandering rivers. Bend shape is always changing with the concave bank eroded and the convex bank deposited. The river bends keep creeping and deforming, and its sinuosity continues to enlarge until natural cutoffs happen. In order to explore the existence of limit sinuosity before natural cutoffs, using Google Earth satellite images, high curvature bends and oxbow lakes of the Yangtze River, Heilong River, Mississippi River and other six rivers (including their tributaries) are selected as statistical samples, whose plane shape parameters are defined and measured. The results show that limit sinuosity of river bends really exists in the statistical sense. When cutoffs happen, the sinuosity doesn’t tend to the infinity. Sinuosity samples of river bends obeyed approximately normal distribution, preliminarily confirming limit sinuosity on the interval [10, 30]. When bend neck width, average channel width and meander neck length gradually decreases, bend sinuosity first rapidly becomes small and then gradually gets stable after reaching the minimum. River bends possess the characteristic of fractal geometry, and its fractal dimension mainly focuses on the interval [1.10, 1.35]. When the fractal dimension increases, the sinuosity slowly increases. Fractal dimension and sinuosity depicting geometry morphology of river bends have consistency.

Key words: River bends, oxbow lakes, limit sinuosity, fractal dimension, cutoffs

Published in: Journal of China Institute of Water Resources and Hydropower Research, Vol. 9, No. 3, 2011

Article ID: 1672-3031 (2011) 03-0176-07