Characteristics of realigned dikes in coastal Europe: Overview and opportunities for nature-based flood protection

Building and raising land: meandering rivers and filling estuaries

“…This suggests that transitional polders may contribute to lower flood risks during storm surges as well, which is in line with findings for managed realignment sites (e.g. Temmerman et al, 2013;Bouma et al, 2014;Van den Hoven et al, 2022), and requires further work.…”

“…Secondly, the minimal area was set to 4 km 2 , i.e. equally large or larger than most current de-embanked areas (see for review: Wolters et al, 2005;Van den Hoven et al, 2022), to have an observable effect on tidal wave propagation in the estuary. Thirdly, the locations for the transitional polders-to-be lacked urban buildings, industry and solar panels to have a minimal impact on society.…”

“…The concept of filling accommodation along estuaries has received increasing attention over the past decades in the form of managed realignment projects (e.g. Wolters et al, 2005;Esteves, 2014;Van den Hoven et al, 2022). Many sites for managed realignment were created by storm-induced dike breaches (e.g.…”

“…With sea-level on the rise and new policies that prioritise nature-based solutions (European Commission, 2021), there is an increasing interest in sustainable measures for flood safety that not only reduce flood risk but also increase ecological value and cause land-level rise (e.g. Esteves, 2014;Schoonees et al, 2019;Van den Hoven et al, 2022). Transitional polders between double dikes are one of these promising measures (Van Belzen et al, 2021) and require further investigation.…”

“…So far, most deliberate de-embankments in estuaries were smaller than 400 ha and were single efforts in individual tidal systems (Wolters et al, 2005;Van den Hoven et al, 2022). Therefore, little is known about how the location of a transitional polder along an estuary influences the import of sand and mud and the tides with an estuary.…”