Abstract

Shelf sedimentation studies have demonstrated that long-term accumulation patterns are heavily influenced by the timing of river sediment discharge relative to oceanographic transport processes. Field studies on the shallow Louisiana shelf allows evaluation of spatial and temporal variability of the seabed during years with distinctly different river-supply terms. The Atchafalaya River discharges sediment to the shelf between February and April, overlapping with the period of frequent cold front passages. The freshly delivered sediment is subject to reworking and onshore/offshore transport by waves, currents, and gravity. Combined time-series and seabed observations indicate episodic periods of fluid mud (high concentration bottom suspensions) during the time of high sediment discharge and cold front activity. These suspensions impact wave attenuation and ultimately the along- and across-shore sediment dispersal. The repeated cycling of cold-front passages often leads to a positive feedback with transport onshore. Effective attenuation of wave energy over the muddy inner shelf inhibits erosion at the coast. Thus, the chenier-plain coast is experiencing high progradation rates, while most of the Gulf coast is eroding.

Presenter Bio

Gail Kineke is a Professor in the Department of Earth and Environmental Sciences at Boston College, and an Adjunct Scientist at the Woods Hole Oceanographic Institution. She has a bachelor's degree in geology from Princeton University and a master,s and Ph.D. in Oceanography from the University of Washington. Before joining the faculty at Boston College, she was a postdoctoral research associate at Woods Hole Oceanographic Institution and an Assistant Professor at the University of South Carolina. Her research interests include coastal and estuarine processes and marine sediment transport. In the most general sense, she tries to understand the physical processes (such as waves, tides and currents) that transport sediments delivered to the coastal ocean by rivers and resulting dispersal systems. Her research has taken her to the Amazon, the Gulf of Mexico, Papua New Guinea, the Gulf of Lyons, and the Adriatic Sea, as well as a number of estuaries in the southeastern US. Her current research includes projects in the Connecticut River estuary and the Huanghe (Yellow River) delta of China.

Publication Date

4-29-2016

Document Type

Presentation

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