Fluvial Hydraulics of Deltas and Alluvial Fans

Delta formation and its associated steam channel hydraulics have been studied using data obtained in a large laboratory flume. The findings for deltas are generally applicable to alluvial fans. Delta or fan shape is directly related to the pattern of stream flow, its loci, and mode of deposition. In response to a change in water discharge, sediment feeding rate or base level, stream channel adjustments on the delta are characterized by the formation of a single channel or multiple distributary channels. The changes in channel pattern are associated with large changes in channel width and stream power expenditure. Stream channel changes are related to the stream’s tendency to seek equal power expenditure along the channel; they also provide delicate adjustments in velocity and sediment load to favor restoration of channel’s equilibrium.