Abstract. The combined effect of global sea level rise and land subsidence phenomena
poses a major threat to coastal settlements. Coastal flooding events are
expected to grow in frequency and magnitude, increasing the potential
economic losses and costs of adaptation. In Italy, a large share of the
population and economic activities are located along the low-lying coastal
plain of the North Adriatic coast, one of the most sensitive areas to relative sea
level changes. Over the last half a century, this stretch of coast has
experienced a significant rise in relative sea level, the main component of
which was land subsidence; in the forthcoming decades, climate-induced sea
level rise is expected to become the first driver of coastal inundation
hazard. We propose an assessment of flood hazard and risk linked with
extreme sea level scenarios, under both historical conditions and sea level
rise projections in 2050 and 2100. We run a hydrodynamic inundation model on
two pilot sites located along the North Adriatic coast of Emilia-Romagna:
Rimini and Cesenatico. Here, we compare alternative extreme sea level
scenarios accounting for the effect of planned and hypothetical seaside
renovation projects against the historical baseline. We apply a flood damage
model to estimate the potential economic damage linked to flood scenarios,
and we calculate the change in expected annual damage according to changes
in the relative sea level. Finally, damage reduction benefits are evaluated
by means of cost–benefit analysis. Results suggest an overall profitability
of the investigated projects over time, with increasing benefits due to
increased probability of intense flooding in the near future.