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| Titel |
Simulation of morphodinamic processes in small coastal systems: application to the Aljezur coastal stream (Portugal) |
| VerfasserIn |
Martha Guerreiro, André B. Fortunato, Anabela Oliveira, Xavier Bertin, Nicolas Bruneau, Marta Rodrigues |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250039316
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| Zusammenfassung |
| In small and shallow coastal streams, morphological changes may have a dramatic effect on
tidal propagation and distortion, on hydrodynamics and, ultimately, on the transport and fate
of water-borne material. Hence, the ability to simulate the morphodynamic evolution
of these dynamic and complex systems can be required for water quality studies.
This work aimed at implementing, validating and exploring the morphodynamic
modelling system MORSYS2D (Fortunato and Oliveira, 2004, Bertin et al., 2009)
in the Aljezur stream, a small and dynamic coastal system located in south-west
Portugal.
Four extensive field campaigns were carried out in 2008 and 2009 to measure bathymetry,
water levels, waves and currents, in both the estuary and the adjoining beach. Between the
two 2009 campaigns, bathymetry was measured on a monthly basis. Data revealed
significant morphological changes, including channel migration and the formation of
sandbars.
The morphodynamic modelling system MORSYS2D consists of a wave model (SWAN –
Booij et al., 1999), a circulation model (ELCIRC – Zhang et al., 2004) and a sediment
transport and bottom update model (SAND2D, Fortunato and Oliveira, 2004), and is
controlled by a script that runs the models, manages the transfer of information between them
and performs control checks.
The model was shown to reproduce successfully the waves, the water levels and the
velocities. Preliminary morphodynamic simulations revealed that the model is highly
sensitive to small changes in the initial conditions, the parameterization of friction and the
sediment transport formulation.
This presentation will describe the calibration and validation of the morphodynamic
modelling system and will investigate on the circumstances that can lead to the inlet closure
(including wave action and river flow).
Acknowledgements
This work was sponsored by the Portuguese Science and Technology Foundation (FCT),
project MADyCOS (PTDC/ECM/66484/2006). The authors thank the developers of the
models ELCIRC and SWAN for making their source codes available and Guillaume Dodet
for providing the time-series of wave spectra.
The first author is grateful to Prof. João Dias for the orientation provided during this
work.
This research would not have been be possible without the participants in the field
campaigns: R. Taborda, C. Andrade, C. Freitas, A.M. Silva, C. Antunes (Faculdade de
Ciências de Lisboa), L. David, P. Freire, R. Capitão, C.J.E.M Fortes, L.S. Pedro, J. Vale, A.
Nahon, D. Neves, C. Zózimo, L. Pinheiro (LNEC), A. Cravo, M. Rosa, C. Monteiro, S.
Cardeira and C. Loureiro (Universidade do Algarve). The authors are grateful for all the
effort and support.
References
Bertin, X., Oliveira, A. and Fortunato, A.B. 2009. Simulating morphodynamics with
unstructured grids: description and validation of a modeling system for coastal applications,
Ocean Modelling, 28/1-3: 75-87.
Booij, N., Ris, R.C. and Holthuijsen, L.H., 1999. A third generation wave model for
coastal regions; Part I: model description and validation. Journal of Geophysical Research,
104: 7649–7666.
Dodet, G., Bertin, X. and Taborda, R. 2010. Wave climate variability in the
North-East Atlantic Ocean over the last six decades, Ocean Modelling, 31: 120 -
131.
Fortunato, A.B. and Oliveira, A. 2004. A modeling system for tidally driven long-term
morphodynamics, Journal of Hydraulic Research, 42/4: 426-434.
Zhang, Y.-L., Baptista, A.M. and Myers, E. P. 2004. A cross-scale model for 3D
baroclinic circulation in estuary-plume-shelf systems: I. Formulation and skill assessment,
Continental Shelf Research, 24/18: 2187–2214. |
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