Laboratory study: Sediment transport in wave-supported gravity currents

A number of recent observational studies on continental shelves have observed high rates of cross-shelf transport in thin layers of highly concentrated fine-grained sediment. These gravity currents are sustained by the combined action of their negative buoyancy and supplemental shear stress provided by surface waves. Wave-supported gravity currents (WSGC) have been identified as an important mechanism for cross-shelf sediment transport on many shelves, yet our understanding of WSGC is limited to observational studies that cannot resolve the velocity or density structure within them.

The goals of this work are to determine the structure and transport in WSGC using a combination of laboratory experiments and prior field observations. The laboratory experiments are being conducted in a 5-m long sediment/wave flume constructed expressly for these experiments and proven to realistically reproduce conditions in the oceanic wave boundary layer. Evaluation of the laboratory results will be guided and motivated by field observations of such flows in three shelf systems (Eel and Po River margins, and Gulf of Papua).

People:   Andrea Ogston, Alex Horner-Devine (UW CEE), Abbas Hooshmand (UW CEE)