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ABSTRACT: The Scheldt is a tidal river that originates in France and flows through Belgium and the Netherlands. The tides create significant
flood risks in both the Flemish region in Belgium and the Netherlands. Due to sea level rise and economic development, flood
risks will increase during this century. This is the main reason for the Flemish government to update its flood risk management
plan. For this purpose, the Flemish government requested a cost-benefit analysis of flood protection measures, considering
long-term developments. Measures evaluated include a storm surge barrier, dyke heightening and additional floodplains with
or without the development of wetlands. Some of these measures affect the flood risk in both countries. As policies concerning
the limitation of flood risk differ significantly between the Netherlands and Flanders, distinctive methodologies were used
to estimate the impacts of measures on flood risk. A risk-based approach was applied for Flanders by calculating the impacts
of flood damage at different levels of recurrence, for the base year (2000) and in case of a sea level rise of 60cm by 2100.
Policy within the Netherlands stipulates a required minimal protection level along the Scheldt against storms with a recurrence
period of 1 in 4,000years. It was estimated how flood protection measures would delay further dyke heightening, which is
foreseen as protection levels are presently decreasing due to rising sea levels. Impacts of measures (safety benefits) consist
of delays in further dyke heightening. The results illustrate the importance of sea level rise. Flood risks increased fivefolds
when a sea level rise of 60cm was applied. Although more drastic measures such as a storm surge barrier near Antwerp offer
more protection for very extreme storms, a combination of dykes and floodplains can offer higher benefits at lower costs.
KeywordsFlood risk management–Cost-benefit analysis–Sea level rise–Floodplain restoration–Ecosystem services
Natural Hazards 04/2012; 57(2):245-266. · 1.53 Impact Factor
