Multigrain seabed sediment transport modelling for the south-west Australian Shelf

Abstract

With increasing concerns about climate change and sea-level rise, there is a need for a comprehensive understanding of the sedimentary processes involved in the erosion, transport and deposition of sediment on the continental shelf. In the present paper, long-term and large-scale seabed morphological changes on the south-west Australian continental shelf were investigated by a comprehensive sediment transport model, Sedsim. The investigated area covers the continental shelf and abyssal basins of the south-western region. The regional seabed is sensitive to environmental forces and sediment supply, and most terrigenous sediment carried down by major rivers is trapped in inland lakes or estuaries. Only a small fraction of fine-grain sediment reaches the continental shelf. The simulation has also confirmed that the Leeuwin Current and high-energy waves play the most important roles in regional long-term seabed evolution. Although the numerical implementation only approximates some forcing and responses, it represents a significant step forward in understanding the nature of potential long-term seabed change as a response to possible climate change scenarios. The 50-year forecast on the seabed morphological changes provides a reference for the management of coastal and offshore resources, as well as infrastructure, in a sustainable way.

eSCAPE: Regional to Global Scale Landscape Evolution Model v2.0

“…As shown in Figs. 5 and 6, the predicted locations of the largest basin outlets match quite well with observations, and many of the biggest simulated deltaic systems are related to sediment transported by some of the world's largest rivers (Milliman and Syvitski, 1992;Syvitski et al, 2003;Li et al, 2009). The model can also be used to evaluate the evolution of drainage systems, the stability of continental flow directions, the exhumation history of major mountain ranges, the timing and geometry of sedimentary body formation (e.g.…”

“…Flow accumulation (FA) calculations are a core component of landscape evolution models as they are often used as proxy to estimate flow discharge, sediment load, river width, bedrock erosion, and sediment deposition. Until recently, conventional FA algorithms were serial and limited to small spatial problems (O'Callaghan and Mark, 1984;Mark, 1988). With ever growing high-resolution digital elevation datasets, new methods based on parallel approaches have been proposed over the last decade.…”

Wave‐influenced deposition of carbonate‐rich sediment on the insular shelf of Santa Maria Island, Azores

“…The bottom shear stress at the threshold of sediment motion is needed for assessing how hydrodynamic processes cause the transport and deposition of sediment particles across shelves. Equations representing threshold of motion stresses typically replicate flow conditions occurring during incipient movement of spherical or near‐spherical particles of quartz density (Miller et al ., 1977; Li & Amos, 1995; Soulsby & Whitehouse, 1997; Soulsby, 1997; Paphitis, 2001; Porter‐Smith et al ., 2004; Griffin et al ., 2008; Wiberg & Sherwood, 2008; Li et al ., 2009; Dalyander et al ., 2013; Oberle et al ., 2014). However, natural marine sediments commonly have varied amounts of biogenic particles of non‐uniform size and shape, leading to thresholds of motion strongly differing from those of uniform quartz particles (Paphitis et al ., 2002; Weill et al ., 2010; Rieux et al ., 2019; de Kruijf et al ., 2021).…”

Physical sedimentary controls on subtropical coastal and shelf sedimentary systems: Initial application in conceptual models and computer visualizations to support archaeology

“…The coastline features rocky promontories between which lie sandy reef‐bounded embayments, some with large fields of coastal dunes, and other more exposed steep coarse beaches (Shore Coastal, ). The highly energetic wave regime, combined with the strong coast‐parallel currents, means that there is a strongly erosional sedimentary regime along most of the coastline and on the adjacent shelf (Carrigy & Fairbridge, ; Li et al., ). The modern bathymetric contours are coast‐parallel, down to the shelf edge at 160–180 m depth and beyond, indicating that the general wave‐dominated regime is likely to have been similar through the last 50 ka or more.…”