Morphology of the Kosi megafan channels | INSTITUT DE PHYSIQUE DU GLOBE DE PARIS

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  Morphology of the Kosi megafan channels

Publication Type:

Journal Article

Source:

Earth Surface Dynamics, Volume 3, p.321-331 (2015)

Abstract:

We report on a new set of measurements on the morphology of braided and meandering threads of<br/>the Kosi megafan, North Bihar, India. All threads develop on a uniform sandy sediment and under a similar<br/>climate. The data set is composed of the width, depth, water discharge and grain size of 51 threads. Downstream<br/>slopes and sinuosity are also available. Using this data set, we show that braided and meandering threads share<br/>common hydraulic geometries. We then use the threshold theory to explain why the aspect ratio of threads is<br/>almost naturally detrended, and rescale the data according to this theory. As expected, the rescaled dimensions<br/>of braided and meandering threads are weakly correlated to water discharge. We propose that the large dispersion<br/>observed, which is common to meandering and braided threads, is the signature of sediment transport, vegetation<br/>or cohesion effects.