The morphodynamics of deltas and their distributary channels

摘要

A consistent database was established to characterize delta morphology, and includes: (1) location, basin morphology, fluvial and sediment discharge, delta morphology, ocean energy, and shelf depth reached by the sub-aqueous delta. Fifty-five deltas were selected to cover the global parameter range, constrained by seasonal satellite image availability. Delta area is best predicted from average discharge and total sediment load feeding the delta. The gradient of a delta plain, measured from the delta apex to the coast along the main channel, is best predicted with a ratio of sediment supply to sediment retention, sediment concentration, and mean water discharge. The number of distributary channels is best predicted by maximum monthly discharge and delta gradient. Widths of distributary channels form a lognormal distribution, with total width a function of water and sediment discharge; mean the tidal range and the maximum monthly-wave height additionally influence channel width.