http://repositorio.lnec.pt:8080/jspui/handle/123456789/1007781 2026-04-04T21:10:29Z 2026-04-04T21:10:29Z Khosravi, M. Fortunato, A. B. Lopez-Ruiz, A. Valle-Levinson, A. Garel, E. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018980 2025-11-27T12:24:04Z 2025-10-01T00:00:00Z

Fortnightly variability of the lateral structure of residual flows along non-rotating estuaries Khosravi, M.; Fortunato, A. B.; Lopez-Ruiz, A.; Valle-Levinson, A.; Garel, E. Residual circulation in estuaries plays a crucial role in controlling salt intrusion, material transport, and ecosystem functioning, making its understanding essential for coastal management worldwide. Despite its importance, the mechanisms driving the transverse structure of residual flows remain insufficiently explored, particularly in relation to the fortnightly tidal variability. This study shows how the main driver of residual flow may switch from baroclinic dominance at neap tide to barotropic dominance at spring tide. Three-dimensional, process-oriented numerical simulations are carried out in an idealized, non-rotating, estuary–shelf system, represented by an 80 km-long semi-closed channel with a 1 km-wide Gaussian-shaped cross-section. This setting is inspired by the Guadiana Estuary (Portugal/Spain), where previous observations have reported a switch of the residual circulation between spring tide and neap tide. To mimic such fortnightly pattern, the model is forced by freshwater inflow at the head and M2 and S2 tidal harmonics at the ocean boundary. Harmonic amplitudes were selected based on a sensitivity analysis. The along channel and temporal variability of the lateral structure of axial residual flows is represented using a non-dimensional parameter derived from the residual inflow that may develop in the deep channel. The simulation results show residual flow transverse structures consistent with theoretical expectations for a baroclinic driver in neap tides and a barotropic driver in spring tides, as confirmed by analyses of the residual momentum equation terms. In these cases, the near-bottom residual flow in the channel is relatively strong and its direction indicates the dominant driver. The study also reveals a previously undocumented transverse structure described by inflows near the channel bed and over the shoals. This structure develops in relation to the Stokes drift when baroclinic and barotropic forcings are relatively balanced across a section.

2025-10-01T00:00:00Z Fortunato, A. B. Freire, P. Rilo, Ana Viseu, T. Rodrigues, M. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018768 2025-07-21T13:30:18Z 2024-06-01T00:00:00Z

Mapping inundation of estuarine margins driven by ocean and fluvial forcings Fortunato, A. B.; Freire, P.; Rilo, Ana; Viseu, T.; Rodrigues, M. Inundation maps are required for spatial planning. This paper describes the generation of inundation maps for the margins of the upstream region of the Tagus estuary (Portugal). Maps are constructed separately for a major river flood (the February 1979 flood) and an extreme storm surge (the February 1941 cyclone), both with return periods on the order of 100 years. All the relevant forcings are considered in the model simulations, including tides, river flow, wind, atmospheric pressure and surface waves. The dykes that protect the margins are explicitly considered by placing a row of grid nodes along their crests. The impact of sea level rise is also assessed.

2024-06-01T00:00:00Z Rodrigues, M. Fortunato, A. B. Martins, R. Jesus, G. Brito, A. Oliveira, A. Nahon, A. Costa, J. L. Alves, E. Korani, Z. Azevedo, A. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018765 2025-07-21T13:30:14Z 2024-06-01T00:00:00Z

CONNECT local coastal monitoring service for Portugal Rodrigues, M.; Fortunato, A. B.; Martins, R.; Jesus, G.; Brito, A.; Oliveira, A.; Nahon, A.; Costa, J. L.; Alves, E.; Korani, Z.; Azevedo, A. CONNECT provides a local, high-resolution, coastal monitoring service. It integrates model-based forecasts and observations to provide physical and biogeochemical data on Portuguese estuaries. The service is demonstrated in two use cases, the Tagus estuary and the Mondego estuary.

2024-06-01T00:00:00Z Sancho, F. E. Oliveira , F. Nahon, A. http://repositorio.lnec.pt:8080/jspui/handle/123456789/1018442 2025-04-16T13:42:33Z 2024-06-01T00:00:00Z

Assessment of soft coastal protection alternatives for Saint-Louis (Senegal) Sancho, F. E.; Oliveira , F.; Nahon, A. The Barbarie spit (Langue de Barbarie) is a 100–400 m-wide West-Africa coastal barrier that has fluctuated in length between 10 and 30 km over the last century (Anthony, 2015). The changes in length reflect the variable position of the Senegal river mouth, where rates of spit growth vary greatly (100 to 700 m/year), depending on variations in wave characteristics, river discharge and river mouth dynamics, combined with barrier-breaching events (Bergsma et al., 2020). The Barbarie sandy barrier protects the island of Saint-Louis, within the Senegal river delta. Of particular significance is the historic city of Saint-Louis, a UNESCO world heritage city (Anthony, 2015). Coastal erosion can be severe along the 2 km stretch in front of Saint-Louis, with retreat rates of up to 20 m/year (Tavenau et al., 2021). Moreover, the coast in front of the city is home to small-craft fishing activity of high socio-economic implications. Given the Saint-Louis settings and the Barbarie spit dynamics, the city is at high coastal erosion and flooding risk. So, informed coastal management is necessary, based on the assessment of alternative coastal protection solutions. Given the world-wide success of several soft-management (beach nourishment) interventions, this paper addresses and compares four alternative solutions, consisting of artificial protective offshore islands and shore-attached peninsulas.

2024-06-01T00:00:00Z