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ASSESSING HYDRODYNAMICS IN TWO PORTUGUESE ESTUARIES: NUMERICAL MODEL COMPARISONS

2018; Frontiers Media; Volume: 5; Linguagem: Inglês

10.3389/conf.fmars.2018.06.00107

2296-7745

Isabel Iglesias, Paulo Avilez‐Valente, Ana Bio, Luísa Bastos,

Coastal wetland ecosystem dynamics

Event Abstract Back to Event ASSESSING HYDRODYNAMICS IN TWO PORTUGUESE ESTUARIES: NUMERICAL MODEL COMPARISONS Isabel Iglesias1*, Paulo Avilez-Valente1, 2, Ana Bio1 and Luisa Bastos1, 3 1 Centro Interdisciplinar de Pesquisa Marine e Ambiental (CIIMAR), Portugal 2 Faculdade de Engenharia, Universidade do Porto, Portugal 3 Departamento de Geociências, Ambiente e Ordenamento do Território, Faculdade de Ciências, Universidade do Porto, Portugal Costal zones are of relevant environmental, economic and societal importance but are difficult to understand given the complexity of their physical, chemical, geological and biological processes and of the associated ecosystem services. An effective and integrated management of the coastal zones, which are often densely urbanized and places of human activities, from leisure to industry, requires a deep understanding of coasts and their systems, including estuaries. These regions and their dynamics are poorly understood, with knowledge limited due to the lack of systematic monitoring and to the complexity of the interface system (1). Numerical models are therefore essential to provide accurate scientific and technical information to policy-makers and support their decisions (2). Numerical modelling can be of interest concerning a broad range of ecosystem services, like supporting the definition of the most adequate zones for tourism activities, water catchment, aquiculture or fisheries, among others, by providing understanding of the hydrodynamic processes and erosion/accretion patterns, and allowing the assessment and prediction of the effects of hazardous events. In this context, and within the scope of the ECOSERVICES project, the hydrodynamic software package openTELEMAC-MASCARET in its 2DH depth-averaged version was applied to two of the main Northern-Portuguese estuarine regions: the Minho and Douro estuaries. The Douro estuary is an urban area with strong currents and recurrent severe floods that cause navigation problems and serious damages to the riverine populations (3, 4). Its dynamics is mainly forced by freshwater flows, which depend on natural high-variability conditions and on the hydropower production schedules at the Crestuma-Lever dam (that limits the estuary) and other national and international up-river dams. On the southern margin of the estuary mouth a sand spit partially obstructs the entry; its morphodynamics is conditioned by natural and human processes (4). To prevent erosion of the sand spit and improve navigability and bank protection, two breakwaters were built a few years ago. These interfered with local sedimentary and hydrodynamic patterns, increasing the area and volume of the sand spit (4, 5). The Minho estuary dynamics are essentially unknown (6). This international estuary, which integrates a European network of areas with interest for nature conservation, presents strong siltation problems, related with high sediment deposition and low currents velocities (7). These patterns produce several bathymetric constraints, like strangling or rapid variations of the bathymetry, and several sand bars that, during low tide, become emerged, increasing navigation problems (8, 9). Several dredging campaigns were carried out to open the navigation channel, with possible implications in the morphological evolution of the estuary and the adjacent coastal areas (7). The hydrodynamics of both estuaries was compared using simulations performed for several scenarios, including high/low and spring/neap tides and high/low river flows, representing the effects of the bathymetric constraints in the Minho estuary and demonstrating that the floods in the Douro region can be harsher in terms of economic losses and structural damage due to the growth of the sand spit after breakwater construction. Acknowledgements This research was partially supported by the Strategic Funding UID/Multi/04423/2013 through national funds provided by FCT – Foundation for Science and Technology and European Regional Development Fund (ERDF) and by the Research Line ECOSERVICES, integrated in the Structured Program of R&D&I INNOVMAR: Innovation and Sustainability in the Management and Exploitation of Marine Resources (NORTE-01-0145-FEDER-000035), funded by the Northern Regional Operational Programme (NORTE2020) through ERDF. References 1. Bastos, L., A. Bio, I. Iglesias (2016). The Importance of Marine Observatories and of RAIA in Particular. Frontiers in Marine Science 3: 1-11. doi: 10.3389/fmars.2016.00140. 2. Iglesias, I., S. Venâncio, R. Peixoto, J.L. Pinho, P. Avilez-Valente, J. Vieira (2016). The Douro Estuary: Modelling comparison for floods prevention. Actas das 4.as Jornadas de Engenharia Hidrográfica. Instituto Hidrográfico. ISBN - 978-989-705-097-8. 3. Portela, L.I. (2008). Sediment transport and morphodynamics of the Douro River estuary. Geo-Marine Letters 28: 77–86. 4. Bastos, L., A. Bio, J.L.S. Pinho, H. Granja, A.J. da Silva (2012). Dynamics of the Douro estuary sand spit before and after breakwater construction. Estuarine, Coastal and Shelf Science 109: 53–69. 5. Teodoro, A.C., J. Pais Barbosa, H. Goncalves, F. Veloso Gomes, F. Taveira Pinto (2011). Extraction of Cabedelo sand spit area (Douro estuary) from satellite images through image processing techniques. Journal of Coastal Research Vol. 56 p. 1740-1744. 6. Zacarias, N., A.J. da Silva (2008). Tide Propagation in the Minho River Estuary (Portugal). 43rd Estuarine & Coastal Sciences Association – International Symposium. 2008. Faculdade de Ciências da Universidade de Lisboa. Lisboa, Portugal. 7. Delgado, A., F. Taveira-Pinto, R. Silva (2011). Hydrodynamic and morphodynamic preliminary simulation of river Minho estuary. 6ª Jornadas de Hidráulica, Recursos Hídricos e Ambiente, 113–126. 8. Reis, J.L., A.S. Martinho, A.A. Pires-Silva, A.J. da Silva (2009). Assessing the influence of the river discharge on the Minho estuary tidal regime. Journal of Coastal Research, SI 56 (Proceedings of the 10th International Coastal Symposium), 1405 – 1409. Lisbon, Portugal, ISSN 0749-0258. 9. Zacarias, N.G. (2007). Influência da batimetria e do caudal fluvial na propagação da maré no estuário do rio Minho. Technical report, Universidade de Évora, 81 pp. Keywords: Estuarine modelling, Hydrodynamics, Estuarine risks, Minho and Douro estuaries, North Portugal Conference: IMMR'18 | International Meeting on Marine Research 2018, Peniche, Portugal, 5 Jul - 6 Jul, 2018. Presentation Type: Poster Presentation Topic: Biodiversity, Conservation and Coastal Management Citation: Iglesias I, Avilez-Valente P, Bio A and Bastos L (2019). ASSESSING HYDRODYNAMICS IN TWO PORTUGUESE ESTUARIES: NUMERICAL MODEL COMPARISONS. Front. Mar. Sci. Conference Abstract: IMMR'18 | International Meeting on Marine Research 2018. doi: 10.3389/conf.FMARS.2018.06.00107 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 30 May 2018; Published Online: 07 Jan 2019. * Correspondence: PhD. Isabel Iglesias, Centro Interdisciplinar de Pesquisa Marine e Ambiental (CIIMAR), Matosinhos, Portugal, isabel.iglesias.fdz@gmail.com Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. 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