VERBI VEnice Research BIbliography
VERBI VEnice Research BIbliography |
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Ferrarin, C., Umgiesser, G., & Amos, C. L. (2006). A 3-d sediment transport model and bed reworking for the venice lagoon. Scientific Research and Safeguarding of Venice, Corila Research Program 2004 Results, IV, 491–501.
Added by: Dott. Alessandro Meggiato (28/05/2014 16:19:12) |
| Tipo di Risorsa: Articolo di Rivista Chiave di citazione BibTeX: Ferrarin2006 Invia la risorsa per email ad un amico View all bibliographic details  |
Categorie: General Keywords: extend abstract corila, idrodinamica, modello matematico, processi ambientali - Environmental Processes, sedimentologia Creatori: Amos, Ferrarin, Umgiesser Collezione: Scientific Research and Safeguarding of Venice, Corila Research Program 2004 Results |
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| Abstract |
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The Venice Lagoon consists of sediments that are mainly cohesive. However, sandy regions can be identified both inside the lagoon and close to the inlets. Venice Lagoon is a tidal-dominated lagoon but with strong wave influences (after Hubbard et al., 1979). It is also classified as restricted (after Kjerve and Magill, 1989) due to the partial chocking of the lagoon by a well-developed, linked barrier island system made of sand (after Carter et al., 1987). The dominant factor governing the long-term evolution of this coastal lagoonal system is the stability and evolution of this barrier island system which is controlled by the availability and supply of sand.
In order to preserve the delicate lagoon ecosystem a modelling approach that combines hydrodynamics, waves and the sediment dynamics of the Venice Lagoon is highly desirable. This model could be used to estimate the actual loss or gain of sediments from the lagoon to the Adriatic Sea and the importance of the various forcing factors that influence these dynamics. Coupling SHYFEM finite element hydrodynamic model with a empirical wave model and SEDTRANS05 sediment transport model we obtain a 3-D sediment transport model. SHYFEM is a three-dimensional hydrodynamic model which uses finite element for horizontal discretization. Sedtrans05 is a one dimensional model of sediment transport for sand and mud under either current or combined waves and currents, on the continental shelf and in coastal waters. It applies the combined wave-current bottom boundary theories to derive the near bed velocity profile and bed shear stresses, and then calculates the sediment transport. It uses the sum of grain, bedload and bedform roughness height in the calculation of the total friction factor. Such a 3-D model resolves the hydrodynamics, computing for every grid point the water level and the barotropic transports and estimating the wave field. The sediment transport module computes the erosion and deposition rates at every element and determines the sediment volume that is injected into the water column for several sediment sizes. After this step the sediments are advected with a transport and diffusion module. For the bedload component a direct advection scheme is used. Multiple grain types are used to track changes in seabed texture, and differential transport of material. Modifications to bed elevation and to the grain size distribution are updated at each time step based on the net erosion and deposition. At each location, the bed is modelled as several layers, the uppermost of them represents the surficial active, or mixed, layer. For each size class, the volume of sediment removed from the bed during any time step is limited by the amount available in the active layer. In this way the model takes into account time-dependent and spatial sediment distribution and bed armouring. The model is freely available on the SHYFEM web page: https://www.ismar.cnr.it/shyfem. Added by: Dott. Alessandro Meggiato |