Sensitivity analysis of Ria de Aveiro hydro-morphodynamics to the sea level rise integration period

Abstract

Global mean sea level has been rising in the last century at a rate of 1.7± 0.5 mm/year, and it is expected that during the 21st century it will rise at a greater rate, intensifying coastal hazards worldwide. The main aim of this study is to evaluate the sensitivity of the hydro and morphodynamics of the Ria de Aveiro lagoon to different local sea level rise estimates expected for the end of the 21st century. The SRES scenario A2 was considered admitting three integration periods (Period A between 2071-2080, Period B between 2071-2100, and Period C between 2091-2100), which are compared to the reference period of 1980-1999 (actual climate). The local sea level rise projections were obtained from the output of the GISS-ER model and pointed to a rise of 0.29, 0.34 and 0.42 m for the periods A, B and C respectively. The morphodynamic model MORSYS2D was applied to the Ria de Aveiro considering each forcing scenario. The residual sediment flux at the inlet region and the lagoon tidal prism were computed and analysed for the actual situation and for the three sea level rise estimates. The residual transport of sediments at the inlet region is mostly seaward both for the actual situation and for the considered scenarios. However its magnitude is very sensitive to the sea level rise: an increase of about 72%, 94% and 123% is expected for the periods A, B and C respectively. The tidal prism is also very sensitive to the mean sea level: an increase of about 19%, 22% and 28% is estimated for the periods A, B and C respectively.