loading page

Cohesive sediment erosion in a combined wave-current boundary layer
  • +3
  • Galen Egan,
  • Grace Chang,
  • Samuel McWilliams,
  • Gene Revelas,
  • Oliver Fringer,
  • Stephen Monismith
Galen Egan
Stanford University

Corresponding Author:[email protected]

Author Profile
Grace Chang
Integral Consulting Inc.
Author Profile
Samuel McWilliams
Integral Consulting Inc
Author Profile
Gene Revelas
Integral Consulting Inc
Author Profile
Oliver Fringer
Stanford University
Author Profile
Stephen Monismith
Stanford University
Author Profile

Abstract

We conducted field work on the shoals of South San Francisco Bay to elucidate the mechanisms driving cohesive sediment erosion in a shallow, wave- and current-driven flow. Compiling data from three deployments, including measurements taken within the combined wave-current boundary layer, we found that waves were strongly correlated to turbulent sediment fluxes across all seasons and a range of deployment depths. Tidal turbulence was only correlated to turbulent sediment fluxes for larger relative depths, or when a wave-driven sediment flux into the boundary layer allowed the tidal shear stress to transport sediment into the overlying flow. Despite the dominance of waves in eroding sediment, we found favorable agreement between in situ boundary layer erosion measurements and laboratory erosion measurements conducted in a steady flume. Results were analyzed in the context of two benthic surveys which provided insight into the sediment bed properties.
Feb 2021Published in Journal of Geophysical Research: Oceans volume 126 issue 2. 10.1029/2020JC016655