EP033-01
Testing morphodynamic theories by comparing and contrasting river deltas
Testing morphodynamic theories by comparing and contrasting river deltas
Thursday, 10 December 2020: 16:05
Virtual
Abstract:
Coastal areas are one of the most dynamic places on Earth's surface. Coastal dynamics can lead to inundation and erosion hazards. They also give us the opportunity to use the instrumental record to test theories of Earth surface processes, further improving predictions that would help to reduce future hazards.
In this talk I will discuss ongoing efforts to understand river delta morphology and morphodynamics. We recently developed a theory predicting that river delta steady state is governed by the ratio between waves, tides, and fluvial forcing at its river mouth. Changes in any of these forcings are expected to lead to adjustment in delta morphology. We use observations of a large number of river deltas globally to test this theory and provide projections of future change. We find that river dams and land-use changes have had a considerable impact on delta morphology and growth rates. Sea-level rise alters the fluvial sediment flux toward the river mouth and is likely to be a significant driver of future wave- and tidal reworking of river deltas.
In this talk I will discuss ongoing efforts to understand river delta morphology and morphodynamics. We recently developed a theory predicting that river delta steady state is governed by the ratio between waves, tides, and fluvial forcing at its river mouth. Changes in any of these forcings are expected to lead to adjustment in delta morphology. We use observations of a large number of river deltas globally to test this theory and provide projections of future change. We find that river dams and land-use changes have had a considerable impact on delta morphology and growth rates. Sea-level rise alters the fluvial sediment flux toward the river mouth and is likely to be a significant driver of future wave- and tidal reworking of river deltas.