Formation of fine sediment deposit from a flash flood river in the Mediterranean Sea

View/ Open
Date
2014-09-09Author
Grifoll, Manel
Concept link
Gracia, Vicenc
Concept link
Aretxabaleta, Alfredo L.
Concept link
Guillen, Jorge
Concept link
Espino, Manuel
Concept link
Warner, John C.
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/6979As published
https://doi.org/10.1002/2014JC010187DOI
10.1002/2014JC010187Abstract
We identify the mechanisms controlling fine deposits on the inner-shelf in front of the Besòs River, in the northwestern Mediterranean Sea. This river is characterized by a flash flood regime discharging large amounts of water (more than 20 times the mean water discharge) and sediment in very short periods lasting from hours to few days. Numerical model output was compared with bottom sediment observations and used to characterize the multiple spatial and temporal scales involved in offshore sediment deposit formation. A high-resolution (50 m grid size) coupled hydrodynamic-wave-sediment transport model was applied to the initial stages of the sediment dispersal after a storm-related flood event. After the flood, sediment accumulation was predominantly confined to an area near the coastline as a result of preferential deposition during the final stage of the storm. Subsequent reworking occurred due to wave-induced bottom shear stress that resuspended fine materials, with seaward flow exporting them toward the midshelf. Wave characteristics, sediment availability, and shelf circulation determined the transport after the reworking and the final sediment deposition location. One year simulations of the regional area revealed a prevalent southwestward average flow with increased intensity downstream. The circulation pattern was consistent with the observed fine deposit depocenter being shifted southward from the river mouth. At the southern edge, bathymetry controlled the fine deposition by inducing near-bottom flow convergence enhancing bottom shear stress. According to the short-term and long-term analyses, a seasonal pattern in the fine deposit formation is expected.
Description
Author Posting. © American Geophysical Union, 2014. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 119 (2014): 5837–5853, doi:10.1002/2014JC010187.
Collections
Suggested Citation
Journal of Geophysical Research: Oceans 119 (2014): 5837–5853Related items
Showing items related by title, author, creator and subject.
-
Sediment transport and deposition on a river-dominated tidal flat : an idealized model study
Chen, Shih-Nan; Geyer, W. Rockwell; Sherwood, Christopher R.; Ralston, David K. (American Geophysical Union, 2010-10-16)A 3-D hydrodynamic model is used to investigate how different size classes of river-derived sediment are transported, exported and trapped on an idealized, river-dominated tidal flat. The model is composed of a river channel ... -
Flood dispersal and deposition by near-bed gravitational sediment flows and oceanographic transport : a numerical modeling study of the Eel River shelf, northern California
Harris, Courtney K.; Traykovski, Peter A.; Geyer, W. Rockwell (American Geophysical Union, 2005-09-30)A large flood of the Eel River, northern California, created a thick sediment deposit between water depths of 50 and 70 m in January 1997. The freshwater plume, however, confined sediment delivery to water depths shallower ... -
Sediment deposition in the lower Hudson River estuary
Woodruff, Jonathan D. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1999-09)This study uses geophysical and sedimentological data collected from the Lower Hudson River estuary to identify the depositional response of the estuary to high river discharge events. Erosional and depositional environments ...