Wave-Climate Asymmetry Influence on Delta Evolution and River Dynamics

Journal Article (Journal Article)

On wave-influenced river deltas, wave-driven sediment redistribution affects river progradation, and therefore avulsions, while avulsions change where sediment is delivered to the coastline, affecting coastline shape. Coastline shape, in turn, affects sediment redistribution rates and patterns. Here we use a numerical model to investigate how the asymmetry of wave climates affects delta avulsion behaviors, which are coupled with delta shape evolution. Increasing wave-climate asymmetry tends to reduce (increase) the curvature of updrift (downdrift) delta flanks, by increasing (decreasing) local shoreline diffusivity. In our model experiments, reduced shoreline curvature restricts the possible updrift post-avulsion river mouth locations, while increased curvature expands the possible downdrift locations, favoring “downdrift avulsions.” However, under some wave climates, local diffusivity on the downdrift flank can become negative, leading to convexity and shoreline accretion, inhibiting downdrift avulsions. Increasing wave heights and decreasing superelevation threshold for avulsions both tend to reduce delta morphologic asymmetry, and therefore avulsion tendency.

Full Text

Duke Authors

Cited Authors

  • Hu, N; Murray, AB; Ratliff, KM; Little, Z; Hutton, EWH

Published Date

  • May 16, 2022

Published In

Volume / Issue

  • 49 / 9

Electronic International Standard Serial Number (EISSN)

  • 1944-8007

International Standard Serial Number (ISSN)

  • 0094-8276

Digital Object Identifier (DOI)

  • 10.1029/2021GL096315

Citation Source

  • Scopus