Location: room 611 of the Wiskunde building (campus De Uithof) Budapestlaan 6, Utrecht.
Date and time: Thursday, March 4, 2010 15:30-16:30. The lecture is preceded by coffee, tea, and cookies from 15.00 to 15.30 hour in the same room.
Abstract: Estuaries receive sediments from both fluvial and marine sources. Locally, large concentrations of suspended sediments are observed in many estuaries. This occurrence of locally elevated suspended sediment concentrations is observed in both the along- and transverse-estuary direction. To investigate the trapping of sediment, an analytical 2DV model approach is employed. The water motion is modeled by the width-averaged shallow water equations, the concentration is obtained by solving the width- averaged advection-diffusion equation. The morphodynamic equilibrium condition is applied to get the sediment availability at the bottom. Model results will be used to gain understanding of the physical processes resulting in sediment trapping.
A comparison of model results with data from the Ems estuary and the James river will made. The Ems river is of particular interest as its deepening between 1980 and 2005 from 4-5 m to 7.3 m in the brackish water zone has significantly altered the tidal and sediment dynamics. The tidal range has increased by a factor 1.5 in the upstream reaches. Furthermore, the surface sediment concentration has increased from 400 mg/l to as much as 4-5 g/l and the position of the turbidity zone has shifted upstream as far as the tidal weir. Using the analytical model, the physical mechanisms resulting in these observed changes will be explained.
Schedule of the Utrecht math colloquium : This year's talks. Last term’s talks. Last year's talks. Guidelines for speakers.
Other math colloquia : TU Delft, Leiden, UvA Amsterdam, VU Amsterdam, Nijmegen.
Organisers : Sasha Gnedin and Paul Zegeling
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