Skip to main content
U.S. flag

An official website of the United States government

Across-shelf sediment transport: Interactions between suspended and bed sediment

December 31, 2002

We use a two-dimensional, time-dependent sediment-transport model to quantify across-shelf transport, deposition, and sorting during wave-driven resuspension events characteristic of those that dominate sediment transport on many continental shelves. Decreases in wave-orbital velocities as water depth increases, and the resulting cross-shelf gradient in bed shear stress favor a net offshore transport of sediment. On wide, flat shelves (slopes ∼0.1%percnt;), these gradients are low, and the depth to which the seabed is reworked depends mainly on bottom shear stress and local sediment availability. On narrow, steep shelves (slopes ∼0.5%percnt;), however, the gradient in bottom stress generates significant cross-shelf suspended sediment flux gradients that create regions of net erosion and deposition. While the magnitude of waves generally determines the water depth to which sediment can be resuspended, erosional and depositional patterns on narrow shelves are sensitive to cross-shelf gradients in wave energy, nonlocal sediment availability, and the direction and magnitude of the cross-shelf current. During energetic waves, cross-shelf divergence of suspended sediment flux can create a coarsened, erosional area on the inner shelf that abuts a region of fine-grained sediment deposition on the mid-to-outer shelf. If currents are strongly shoreward, however, flux divergence leads to erosion over the entire shelf.

Publication Year 2002
Title Across-shelf sediment transport: Interactions between suspended and bed sediment
DOI 10.1029/2000JC000634
Authors Courtney K. Harris, Patricia L. Wiberg
Publication Type Article
Publication Subtype Journal Article
Series Title Journal of Geophysical Research C: Oceans
Index ID 70191432
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center