Benoit, Michel

Fossati, Mónica

Huybrechts, Nicolas

Pham Van Bang, Damien

Piedra-Cueva, Ismael

Santoro, Pablo

Tassi, Pablo

English

Hydraulic Engineering Repository

Conference Paper, Published VersionSantoro, Pablo; Fossati, Mónica; Piedra-Cueva, Ismael; Huybrechts,Nicolas; Tassi, Pablo; Benoit, Michel; Pham Van Bang, DamienHydrodynamic and fine sediment transport numericalmodelling, application to the Río de la Plata andMontevideo BayZur Verfügung gestellt in Kooperation mit/Provided in Cooperation with:TELEMAC-MASCARET Core GroupVerfügbar unter/Available at: https://hdl.handle.net/20.500.11970/104320Vorgeschlagene Zitierweise/Suggested citation:Santoro, Pablo; Fossati, Mónica; Piedra-Cueva, Ismael; Huybrechts, Nicolas; Tassi, Pablo;Benoit, Michel; Pham Van Bang, Damien (2015): Hydrodynamic and fine sediment transportnumerical modelling, application to the Río de la Plata and Montevideo Bay. In: Moulinec,Charles; Emerson, David (Hg.): Proceedings of the XXII TELEMAC-MASCARET TechnicalUser Conference October 15-16, 2015. Warrington: STFC Daresbury Laboratory. S.119-125.Standardnutzungsbedingungen/Terms of Use:Die Dokumente in HENRY stehen unter der Creative Commons Lizenz CC BY 4.0, sofern keine abweichendenNutzungsbedingungen getroffen wurden. Damit ist sowohl die kommerzielle Nutzung als auch das Teilen, dieWeiterbearbeitung und Speicherung erlaubt. Das Verwenden und das Bearbeiten stehen unter der Bedingung derNamensnennung. Im Einzelfall kann eine restriktivere Lizenz gelten; dann gelten abweichend von den obigenNutzungsbedingungen die in der dort genannten Lizenz gewährten Nutzungsrechte.Documents in HENRY are made available under the Creative Commons License CC BY 4.0, if no other license isapplicable. Under CC BY 4.0 commercial use and sharing, remixing, transforming, and building upon the materialof the work is permitted. In some cases a different, more restrictive license may apply; if applicable the terms ofthe restrictive license will be binding.Hydrodynamic and fine sediment transport numerical modelling, application to the Río de la Plata and Montevideo Bay  Pablo Santoro, Mónica Fossati, Ismael Piedra-Cueva Instituto de Mecánica de los Fluidos e Ingeniería Ambiental Universidad de la República Montevideo, Uruguay psantoro@fing.edu.uy, mfossati@fing.edu.uy, ismaelp@fing.edu.uy Nicolas Huybrechts Roberval Laboratory, LHN (UTC) CEREMA Compiègne, France nicolas.huybrechts@cerema.fr Pablo Tassi, Michel Benoit Saint Venant Laboratory for Hydraulics EDF R&D Chatou, France pablo.tassi@edf.fr, michel.benoit@edf.fr  Damien Pham Van Bang Saint Venant Laboratory for Hydraulics CEREMA Chatou, France damien.pham-van-bang@cerema.fr   Abstract— The objective of this work is to develop a high resolution wave-current-sediment transport model to simulate the flow field and sediment transport processes of the Río de la Plata estuary and specifically at Montevideo Bay area. Numerical results using the depth-averaged modules of the TELEMAC-MASCARET Modelling System show excellent agreement when compared with observed sea surface elevation, currents, and wave parameters at several stations in the estuary. Preliminary results show a good representation of the suspended sediment concentration series near Montevideo Bay. I. INTRODUCTION Montevideo Bay hosts the main port of Uruguay along with a large industrial development. Nowadays there are many maritime engineering projects in the area, including the construction of new breakwaters, land reclamation for container terminals, navigation channels deepening, etc. All these projects need a reliable characterization of the hydrodynamics in the area and also for some of them the sediment dynamics. Numerical modelling is a powerful tool in that sense, not only for the design of these projects but also to assess their impact on the whole area. In this work the open source TELEMAC-MASCARET Modelling System (TMS) is implemented for the Río de la Plata estuary with special attention to Montevideo Bay in order to study the fine sediment dynamics. Previous studies of our group have been focused on the general hydrodynamic and fine sediment dynamics for the whole estuary [1],[2]. By using the finite elements/volumes technique the TMS works with non-structures meshes allowing to cover big domains increasing the resolution on the areas of interest which can have complex geometries e.g. harbours. As a first approach we started to work using the depth averaged modules of the TMS. Although we know the limitations of this approach for an estuarine application, it aims to be an efficient tool in terms of computation times, which is very important for example during the evaluation of several “what-if” scenarios for engineering projects. II. STUDY AREA The Río de la Plata is located on the east coast of South America. Its axis runs from NW to SE and is approximately 280 km long. Its surface area is approximately 35,000 km2, and its width varies from 20 km at the innermost part to approximately 220 km at its mouth (Fig. 1). The river communicates freely with the ocean and experiences seasonal freshwater discharge from its two major tributaries (the Paraná and Uruguay rivers), with annual average discharge of approximately 16,000 m3/s and 6,000 m3/s, respectively. Two main regions can be identified based on the morphology and dynamics of the Río de la Plata. A shallow area located along the Punta Piedras-Montevideo line separates the inner region from the outer region. The inner region has a fluvial regime, with no stratification or preferential flow direction. In the outer region, the increase in river width generates complex flow patterns. This outer region is formed by brackish waters of variable salinity that are influenced by the tides, the winds, and the contribution of fresh water from the river basin. The tidal regime is dominated by the M2 component, followed by the O1 component which is responsible for the diurnal inequality. The tidal amplitude is greater along the Argentinean coast (order of 1 m), while it is about 0.4 m along the Uruguayan coast. The meteorological tide (storm 22nd Telemac & Mascaret User Club STFC Daresbury Laboratory, UK, 13-16 October, 2015   TABLE III.  WAVE PARAMETERS STATISTICS. Wave Parameter Statistic PB 2009 HV 2006  RMSE (m) 0.16 0.21 Hs ME (m) -0.02 -0.002  Corr 0.89 0.86  RMSE (s) 2.4 3.9 Tp ME (s) 0.5 3.4  Corr 0.34 0.42 # Data 916 2180  To evaluate the relative importance of the oceanic boundary conditions (swell waves) and the local wind effect (sea waves), two idealized simulations were made. One considering only the wind as forcing, and other taking into account only the oceanic boundary conditions propagation. The results (Fig. 7) show that at PB station the local wind is the main forcing.   Figure 9.  Wave boundary conditions influence. Comparison at PB station during Jan – Feb 2009. However at HV stations it can be seen that the oceanic boundary conditions play a more important role (Fig. 8).  Figure 10.  Wave boundary conditions influence. Comparison at HV station during Jan – Feb 2009. C. Sediment transport model The sensitivity analysis showed that all the parameters have a great impact on the sediment transport model results. The critical shear stress for deposition was set at a very high value (10e4 Pa). It means we are considering the simultaneous deposition-erosion paradigm, where deposition take place continuously at a rate D=Ws.SSC. This configuration has been proposed for engineering applications at low-concentration cohesive sediment suspensions [11]. After a preliminary calibration based on the SSC observed at PB, the selected parameters are: settling velocity 1e-4m/s, reference concentration for settling velocity 0.1kg/m3, critical shear stress for erosion 0.1 Pa, Partheniades coefficient 2e-6 kg/m/s.  Fig. 11 shows the model results during May 2009 at PB station. The first two panels show some of the main hydrodynamic variables, the current intensity and significant wave height. The third panel shows the simulated total bottom stress; wave and current bottom stresses are also included. It is clearly seen that the highest values of bottom stress are related to strong waves which are associated to storm conditions at the Río de la Plata. Finally the last panel shows the suspended sediment concentration series. It can be seen that the model reproduce the general behaviour of the SSC series. During calm conditions (small wave heights) the model seems to overestimate the SSC. It represented reasonably well the re-suspension during the two storm events that took place in the presented period. 

Hydrodynamic and fine sediment transport numerical modelling, application to the Río de la Plata and Montevideo Bay

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Hydrodynamic and fine sediment transport numerical modelling, application to the Río de la Plata and Montevideo Bay

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