Reviewing the evidence for risk reduction by natural coastal habitats world-wide: when and where they have worked

---

Siddharth Narayan, Michael W. Beck, Borja Reguero, Jane C. Ingram

Monday 29 june 2015

15:05 - 15:20h at North America (level 0)

Themes: (T) Flood risk management and adaptation, (ST) Adaptation measures

Parallel session: 2I. Floodrisk - Adaptation

---

Coastal risk reduction strategies world-wide face multiple challenges: rising sea-levels, more frequent flooding, greater exposure and increasingly threatened natural coastal habitats. Over the last three to four decades, a body of evidence has been growing that indicates that coastal habitats can be managed alongside artificial defences to reduce the risk of flooding. Many countries are moving towards approaches that use more natural and nature-based approaches for risk reduction. If executed effectively, such approaches can serve to conserve natural habitats, reduce risk from low-magnitude flood events and storms, and reduce exposure. Wide-spread implementation of such approaches remains absent due, in part, to uncertainty around the appropriate engineering, economic, habitat management and policy measures. The “Science for Nature and People” (SNAP) Coastal Defenses project is a global collaboration of researchers from engineering, ecological, economic and policy disciplines to examine the evidence for the effectiveness of habitats in coastal risk reduction and provide guidelines to inform their appropriate use. This paper presents initial results from a systematic global review of the wave attenuation function of coastal habitats. The synthesis focuses on wave reduction by coastal habitats and reviews 68 field and field-based studies across mangroves, marshes, reefs and wetlands. An online, interactive database of examples of the use and effectiveness of natural habitats in risk reduction is also presented.