抄録
Rivers form deltas wherever they flow into standing water such as a lake, a reservoir or the ocean. Under conditions of constant base level of standing water deltas can be expected to gradually prograde outward, so that the delta shoreline regresses “seaward.” Rising base level can not only slow this progradation, but reverse it, so that the shoreline migrates landward, or transgresses. An extreme limit of this case is one of shoreline starvation, for which the supply of sediment at the shoreline drops to zero and the delta goes into transgressive autoretreat. A 1D morphodynamic model of delta response including backwater effect is developed to clarify the response of delta to sea level rise. The simulations revealed that the interaction between sediment supply and sea level rise determines whether or not a) the delta continues to prograde under conditions of sea level rise, or b) the delta begins to transgress and eventually goes into autoretreat.
