Relation between bankfull geometry of alluvial rivers and flow duration curve

摘要

Bankfull discharge has long been estimated to correspond to the discharge with a 1.5-year or 2-year recurrence interval. Although bankfull discharge and corresponding bankfull geometry have been important parameters with which to characterize rivers, the formative processes of bankfull geometry remain unexplained. Here we propose a physically-based explanation of the relation between bankfull geometry of alluvial rivers and hydrology, and in particular the flow duration curve. In this study, we develop a numerical model to explain the balance between sediment gain to the floodplain due to overbank deposition and sediment loss from the floodplain caused by bank erosion due to lateral channel migration, and how this balance establishes bankfull geometry.