Flooding assessment under sea level rise scenarios: Ria de Aveiro case study

Abstract

Sea level rise is an important consequence of climate change with a significant impact on society and ecosystems. The present work aims to assess the sensitivity of Ria de Aveiro marginal flooded area to the sea level rise. A previous version of the hydrodynamic model ELCIRC was improved extending its numerical grid through the inclusion of the intertidal areas and the marginal topography. The present configuration was calibrated comparing model predictions with sea surface elevation data recorded at ten stations distributed throughout the lagoon. The root mean square error and the SKILL were computed, and generally an excellent/ good agreement between predicted and observed sea surface elevation data was found. Once calibrated, the model was used to simulate the lagoon flooded area under present mean sea level and under two local sea level rise scenarios (0.42 m and 0.64 m), considering mean and spring tide conditions. In average was found an increase of 22% and 35% of the lagoon flooded area, respectively, relatively to the present. Additionally, an increase of 15% and 23% was found for the tidal prism at the inlet, for sea level rise scenarios of 0.42 m and 0.64 m, respectively. Numerical results evidenced that sea level oscillations induce important changes in the lagoon flooded area as well as on the local hydrodynamics. Consequently some activities developed in the lagoon margins may be in jeopardy, i.e. the agricultural fields located at the margins of S.Jacinto channel will be inundated by saltwater, if these sea level rise projections are confirmed.