RESPONSE OF RIVER CHANNEL PATTERNS TO THE SPATIALLY VARYING SUSPENDEDSEDIMENT CONCENTRATIONS

River channel pattern transformation is dealt with in a broad backgrou nd of suspended sediment concentration, varying from low, medium, high to hyperconcentration. Based on data from about 100 alluvial rivers i n China, suspended sediment transport rate has been plotted against me an annual water discharge, showing that ail points can be divided into four belts by three straight lines, as stable braided pattern, meande ring pattern with ordinary sediment concentrations, wandering braided pattern, and meandering pattern with hyperconcentration of sediment. T his picture of channel pattern transformation can be well explained by the law of the water flow's energy expenditure varying with its sedim ent concentration. The energy expenditure increases with sediment conc entration, reaching a maximum, then declines. Rivers falling in differ ent ranges of sediment concentrations adjust their own energy expendit ure in different manners, leading to occurrence of different channel p atterns.