Vulnerability and Risk to Sea-Level rise on the Continental Atlantic coast of Portugal

18:00 Tuesday 28 May




Carlos Antunes (Portugal) 1,2; Carolina Rocha (Portugal) 2; Cristina Catita (Portugal) 1,2

1 - Faculdade de Ciências da Universidade de Lisboa; 2 - Instituto Dom Luiz

Continental Atlantic coast of Portugal has hundreds of thousands of people in the coastal zone, with activities of high economic value and concentration of infrastructures that need to be protected from any natural coastal hazard, namely the consequent of sea level rise (SLR).

In the context of strategies for adaptation to climate change, a correct and accurate assessment of the physical vulnerability to SLR is essential. This study is a contribution to the implementation of the inundation standards imposed by European Directive 2007/60/EC, which requires each member state to assess the vulnerability associated with SLR and floods caused by the occurrence of extreme events.

Therefore, coastal vulnerability inContinental Atlantic coast of Portugal was evaluated for 2025, 2050 and 2100 with different scenarios of extreme sea level for different return periods due to sea level rise and extreme events, for which a map of coastal physical vulnerability and risk was produced and based on the methodology using Geographic Information Systems (GIS).

A Flood Hazard Index (FHI), with classes ranging from 1 (Very Low) to 5 (Extreme), with a given SLR scenario is represented on flood maps for an extreme tidal maximum level. The FHI is determined on flood probabilistic bases (five probability intervals of 20% of amplitude), fixed to a central estimate of a mean sea level projection of intermediate hazard, both for coastal and inlet areas.

The Coastal Physical Vulnerability Index (CPVI), corresponding to the physical susceptibility of flood, is a composite index and has values from 1 (Very Low) to 5 (Extreme). It is estimated from a criterion of weights, with the Flood Scenario and six other physical parameters: Hydrographic Network, Type of Coast, Distance to Coast Line, Geology, Geological Drift and Land Use.

Finally, the authors propose a Coastal Risk Index (CRI) that allows the assessment and the identification of the areas that are in early risk and must be prioritized for early planned adaptation and, consequently, giving a contribution for cost optimization and a guarantee of economic and social sustainability. For this, six parameters of exposure were selected: resident population, infrastructures, communication routes, land use and ecological area, which are complemented with a Potential Damage value.