NATURE-BASED FLOOD RISK REDUCTION VIA MULTIPLE LINES OF DEFENSE

Sea level rise, land subsidence and population growth lead to steadily increasing flood risks in low-lying coastal areas. Hard defense structures such as dikes dams should be regularly heightened strengthened sustain their protective function. Further, hard can induce negative effects on the surrounding ecosystem. Therefore, nature-based approaches risk reduction are increasingly promoted. Vegetated foreshores (such salt marshes mangrove forests) reduce wave loads (Vuik et al., 2016). Furthermore, they able keep pace with sea rise due natural sediment accretion. However, cannot always exist front of defenses, for example because shipping lanes, protected habitats or harsh waves currents. Even situations, safety enhanced by creating between multiple lines (double dikes). In this study, we investigate effectiveness, costs protection benefits via defense.