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| Titel |
Tidal wetland conservation and restoration for flood mitigation in estuaries and deltas: examples and global potential |
| VerfasserIn |
Stijn Temmerman, Sven Smolders, Jeroen Stark, Patrick Meire |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250098136
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| Publikation (Nr.) |
 EGU/EGU2014-13781.pdf |
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| Zusammenfassung |
| Low-lying and densely populated deltas and estuaries are world widely exposed to flood risks
caused by storm surges. On the one hand, global change is increasing these flood risks
through accelerating sea level rise and increasing storm intensity, but on the other hand,
local-scale human impacts on deltas and estuaries are in many cases even more increasing the
vulnerability to floods. Here we address the degradation and reclamation of tidal
wetlands (i.e. salt marshes in the temperate zone and mangroves in the tropical
zone) as a major source for increasing vulnerability to flooding of estuaries and
deltas. Firstly, we present examples of flood mitigation by tidal wetland conservation
and restoration, and secondly we explore the potentials and limitations for global
application of this approach of ecosystem-based flood defense (see Temmerman et al.
2013).
First, we use the Scheldt estuary (SW Netherlands and Belgium) as an example where
historic wetland reclamation has importantly contributed to increasing flood risks, and where
tidal marsh restoration on the previously reclaimed land is nowadays brought into
large-scale practice as an essential part of the flood defense system. Based on data and
hydrodynamic modelling, we show that large-scale historic marsh reclamation has
largely reduced the water storage capacity of the estuary and has reduced the friction
to propagating flood waves, resulting in an important landward increase of tidal
and storm surge levels. Hydrodynamic model scenarios demonstrate how tidal and
storm surge propagation through the estuary are affected by tidal marsh properties,
including the surface area, elevation, vegetation and position of marshes along the
estuary. We show that nowadays tidal wetland creation on previously reclaimed
land is applied as an essential part of the flood defense system along the Scheldt
estuary.
Secondly, a global analysis is presented of the potential application of tidal wetlands in
flood mitigation in estuaries and deltas worldwide. We discuss the societal benefits and
drawbacks of wetland creation for flood defense, and provide an estimation of where on Earth
this approach could be feasible. This shows that many of the largest urban populations that
are at risk from coastal flooding, are located in large deltas and estuaries, such as in
Southeast Asia, North America and Europe. We argue that many of these vulnerable
areas are potentially well suited to include wetland conservation and restoration as
an essential part of adaptation and mitigation strategies against storm surge flood
risks.
References:
Temmerman S., Meire P., Bouma T.J., Herman P.M.J., Ysebaert T., De Vriend H.J. (2013)
Ecosystem-based coastal defense in the face of global change. Nature, 504, P. 79-83,
doi:10.1038/nature12859. |
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