Necessary conditions for a meandering-river avulsion

摘要: There is as yet no rational basis for predicting the conditions leading to avulsion of a meandering river. Here we present conceptual model and quantify it under simplifying assumptions first step toward construction stability diagram initiation. It assumed initially that rectangular crevasse channel arbitrary depth cut into levee Because water entering derived from relatively high in main flow, contains low concentrations suspended solids. Consequently, flow capacity entrance eroded. Deepening increases crevasse-channel discharge, concentration solids supplied, because more sediment-laden waters are tapped deeper channel. The predicted deepen until its sediment-carrying satisfied by Whether an will occur particular combination initial depends upon whether there exists steady-state hydraulic sediment-transport depths equal or less than main-channel depth. This quantified writing unsteady, gradually varied, one-dimensional conservation mass momentum equations sediment transport through Sediment computed integral cross-sectional mean velocity Rouse profile. Solutions show stable channels exist only combinations height bed relative ratio slope slope.