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In the current context of climate change, understanding the effects of the changing conditions on estuaries is of utmost importance to protect populations and ecosystems. Given the diversity of impacts depending on the region, there is a need for local and dedicated studies to understand and mitigate the risks. Numerical models can provide forecasts of extreme floods and sea-level rise (SLR). However, they can present inaccuracies. In this work, the ensemble technique was applied to improve the numerical modeling forecasting for estuaries by considering scenarios of extreme river flow discharges (EFDs) and SLR scenarios for 2050 and 2100. The simulations were performed for two different estuarine regions in northern Portugal, and the superensemble was constructed with the results of two different numerical models. The results differed per estuary, highlighting the importance of a local approach. For the Douro estuary dynamics, the results showed that for the EFD, the effects of the SLR were not noticeable, indicating that, in this estuary, the river component was more important than the maritime component. In contrast, the Minho estuary dynamics were found to be affected by the SLR along the whole estuarine region, indicating a maritime influence and a worsening of the flood conditions for future scenarios., This research was partially supported by the Strategic Funding UIDB/04423/2020 and UIDP/04423/2020 through national funds provided by the FCT—Foundation for Science and Technology and European Regional Development Fund (ERDF). This contribution was also funded by the project EsCo-Ensembles (PTDC/ECI-EGC/30877/2017), co-financed by NORTE 2020, Portugal 2020, and the European Union through the ERDF, and by the FCT through national funds.

Ponencia presentada en: XII Congreso de la Asociación Española de Climatología celebrado en Santiago de Compostela entre el 19 y el 21 de octubre de 2022. [EN]Numerical models are essential tools for simulating the hydromorphodynamics of aquatic systems, making it possible to anticipate and predict the effects of anthropogenic interventions, extreme events and climatic changes, and promoting effective and integrated coastal management. However, the results of the models present uncertainties related to errors and inaccuracies in the analysis of the results and in the initial and forcing conditions. Given the need to have accurate forecasts, it is crucial to implement new solutions to avoid such errors. The main objective of the EsCo-Ensembles project is to apply the ensemble technique to improve forecasts in estuarine areas. Two numerical models were chosen to represent the hydromorphodynamics of two Portuguese estuaries considering various historical scenarios. The models’ results were combined using a weighted average, showing that the best forecast results were obtained for ensembles built with techniques that consider the predictive capacities of the individual models. The ensemble technique will be applied to predict future states associated with predicted sea level rise and extreme situations. Preliminary results show an aggravation of the flood level associated with extreme events in the Duero estuary due to the configuration of the mouth, but with little effect of the sea level rise. However, in the Miño estuary, a clear effect of the sea level rise along the estuary has been observed, with a reduction in velocities and increased flood areas. [ES]Los modelos numéricos son herramientas imprescindibles para simular la hidromorfodinámica de los sistemas acuáticos, permitiendo anticipar y prever los efectos de intervenciones antropogénicas, eventos extremos y alteraciones climáticas, y promoviendo una gestión costera eficaz e integrada. Sin embargo, los resultados de los modelos presentan incertidumbres relacionadas con errores e imprecisiones en el análisis de los resultados y en las condiciones iniciales y de forzamiento. Dada la necesidad de tener pronósticos precisos, es crucial implementar nuevas soluciones para evitar tales errores. El principal objetivo del proyecto EsCo-Ensembles es aplicar la técnica de ensembles para mejorar las previsiones en zonas estuarinas. Se escogieron dos modelos numéricos que simularon la hidromorfodinámica de dos estuarios portugueses considerando diversas condiciones históricas. Los resultados de los modelos se combinaron utilizando una media ponderada, demostrando que los mejores resultados de previsión se obtuvieron para ensembles construidos con técnicas que consideran las capacidades predictivas de los modelos individuales. La técnica de ensembles será aplicada para prever estados futuros asociados con la elevación del nivel del mar prevista y situaciones extremas. Resultados preliminares demuestran un agravamiento del nivel de inundación asociado con eventos extremos en el estuario del Duero debido a la configuración de la desembocadura, pero con poco efecto de la subida del mar. Sin embargo, en el estuario del Miño se ha observado un efecto claro de la subida del nivel del mar a lo largo del estuario, disminuyendo las velocidades y aumentando las zonas de inundación. Esta investigación fue financiada por el Fondo Estratégico UIDB/04423/2020 y UIDP/04423/2020 a través de fondos nacionales de la FCT—Fundação para a Ciência e a Tecnologia y del Fundo Europeu de Desenvolvimento Regional (FEDER). También ha sido bastosfinanciado por el proyecto EsCo-Ensembles (PTDC/ECIEGC/30877/2017), FCT, NORTE 2020, Portugal 2020 y la UE (FEDER).

Presented at: Coastal Structures Conference 2019, Hannover, Germany, September 30th – October 2nd, 2019

The erosion processes acting on the river Douro's sandspit have been pushing it inwards into the estuary and reducing its size and volume. The strong waves that often hit the river mouth and the constant silting up of the access channel make the navigation in this area difficult and dangerous. In order to improve the navigational conditions in the river mouth and stimulate the recovery of the sandspit, two breakwaters were built. This study compared the behavior of the sandspit before and after the construction of the breakwaters. The results obtained show that, up to this date, the breakwaters seem to be generating the desired recovery of the sandspit and preservation of the conditions of the access channel.