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Morphodynamic evolution of dredged sandpits

Abstract: Numerical modeling of dredged pits is conducted to investigate the hydrodynamic and morphodynamic interaction in offshore sand extractions. Based on an analytical formulation, a semianalytical numerical model (MEMPITS) has been developed to study the morphodynamic evolution of offshore (ho > 20 m) sand borrow areas. The numerical model has been applied to study the morphodynamic evolution of two offshore sand borrow areas in the Balearic Islands (Spain). Field data allowed a detailed characterization of the evolution of the sandpits. Time series of local hydrodynamics have been obtained using generation models (hindcast) combined with local wave and flow models. A verification of the simple model has been carried out using relatively slight adjustments to the calibration factors. The simple model provides good estimates of the infill rate and migration velocities of the offshore pits on the scale of years. This semianalytical tool allows a quick systematic investigation of the physical mechanisms as well as a detailed sensibility analysis regarding the pit design parameters. These parameters include location (water depth), pit length, width, depth, and orientation with respect to the mean flow. A nondimensional analysis based on the model is also carried out to explore the role of the different variables involved in the evolution of offshore sandpits. Based on the field data and the nondimensional analysis, some basic design recommendations for offshore sandpits are proposed.

 Authorship: González M., Medina R., Espejo A., Tintoré J., Martin D., Orfila A.,

 Fuente: Journal of Coastal Research 2010, 263, 485-502

 Publisher: Coastal Education and Research Foundation

 Publication date: 01/05/2010

 No. of pages: 18

 Publication type: Article

 DOI: 10.2112/08-1034.1

 ISSN: 0749-0208,1551-5036