Artigos de Revista

Continental Portugal presents an extensive and diversified coastal zone which concentrates the main public and private infrastructures of the different economic sectors, as well as the main critical infrastructures. This area is also characterized by a high population density, being a differentiated territory in geophysical, biological and landscape terms. The wave regime is highly energetic, and storms are frequent. In the last decades, the coast of continental Portugal has been affected numerous times by overtopping and coastal flooding processes. Identifying the critical coastal typologies affected by flooding can contribute to a comprehensive flood risk management framework for the Portuguese coastal zones. Hence, a historical database of coastal flooding occurrences was created for the period 1980–2018 based on national and regional newspapers. For this period 650 occurrences were identified as well as 1708 impacts associated with them. In terms of impacts, the typologies associated with public areas, human impacts, the natural system, environmental degradation and buildings stand out. Results provide relevant temporal and spatial information about coastal historical flood occurrences related to extreme storm events and associated impacts, and contribute to the design of a risk framework.

The correct calculation of forces and moments caused by wave action over crown wall structures is critical for their design. There are several existing equations for this, some of which are sanctioned in practice as it is the case for Jensen (1984) and Bradbury et al. (1998), Günback and Gökce (1984), Martin et al. (1999), Berenguer and Baonza (2006), and Pedersen (1996) and Nørgaard et al. (2013). These equations are the main tool for the design of breakwater crown walls and their accuracy is crucial to ensure the stability of the crown wall, especially when considering the sea level rise due to climate change and the possible damage of the armor, since both aspects are not usually considered in most original design studies. In a scenario of climate change, it is very important to estimate the possible changes in security factors due to both these aspects, comparing the results with the original design ones. This paper has as main objective to analyze it for the case study of Ericeira rubble mound breakwater in Portugal. For this, a comparison of the results using those equations and different scenarios including the current, considering sea level rise and armor damage, were performed to extract some conclusions: the increase in the sea level in the case study was not significant and therefore its incidence is very small; and the damage to the main armor by losing pieces at the berm is much more important in this case study, so it is essential to carry out the proper maintenance of the design section. On the other hand, horizontal forces are more conservative using Pedersen and Nørgaard equations, obtaining the lowest value with Martin. Regarding uplift pressures, Martin gives the lowest value, while the most conservative values are given by Günbak and Gökce’s for two scenarios, and Pedersen and Nørgaard for the other two scenarios. Furthermore, the sliding safety coefficient is more conditioning than overturning the safety coefficient in all the scenarios.