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Reef enhancement and vegetation restoration to enhance coastal resilience in Grenville Bay

Grenada Grenville Bay

Community planned and implemented reef enhancement and mangrove restoration aims to break wave energy, reduce coastal erosion, and create a habitat for fish, coral, and other species.

With the support of a partnership between the Nature Conservancy, Grenada Fund for Conservation, and Grenada Red Cross, residents of Grenville Bay have carried out reef enhancement and restored coastal vegetation to combat the consequences of sea level rise including coastal erosion, flooding, and greater storm surges. As an alternative to structural measures to combat coastal erosion that can sometimes compromise coastal habitats, reef enhancement aims to strengthen existing reefs through the building and planting of artificial reef-like structures. These structures will over time become integrated into the existing reefs through the commingling of habitats and coral regeneration. Reef enhancement measures improve the capacity of formerly degraded reefs to break wave energy, reduce coastal erosion, and minimise flooding. The structure used in Grenville Bay provides a stable substrate for coral colonisation and restoration of habitats for fish and other species. The design of the reef enhancement project was informed by wave energy modelling, in-depth measurements of the seabed, and continuous engagements with community members of Grenville. The solution was intentionally made modular, easy to assemble on-site, and significantly porous to allow for habitat enhancement. Fishers and commercial divers from the area both constructed and installed the artificial reef using locally available materials including cement, steel, cinder blocks, and stones from an adjacent quarry. Community members also worked to improve the biological barrier of the shoreline through the planting and nursing of mangrove seedlings to restore the habitats that had previously been lost to coastal erosion.

Case effectiveness on

Climate change

Mitigation: Not reported

Climate mitigation benefits were not quantified or reported. However, the planting and regeneration of a lost mangrove habitat and degraded reef structure is likely to contribute to restoring the carbon sink potential of the area.

Adaptation: Positive

Although not quantified, residents of Grenville have reported that reef enhancement had succeeded in breaking wave energy as designed, likely contributing to potential reductions in coastal erosion and flooding.

Ecosystem health

Ecological effect: Positive

Anecdotal accounts report that fish, octopus, and lobster have moved into the artificial reef structure. Within 12 months of installation, a significant level of coral recruitment was observed on various parts of the structure.

Socioeconomic outcomes

We are currently working on adding the case effectiveness on socioeconomics.

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Mangrove Seedlings
Photo © Bishnu Sarangi

Intervention type

  • Created habitats
  • Restoration
Conducted at landscape scale

Ecosystem type

  • Created other
  • Coastal

Climate change impacts addressed

  • Coastal erosion
  • Coastal inundation
  • Storm surge

Instigators

  • International conservation/environment organization
  • Other
  • National conservation/environment organisation

Societal challenges

  • Biodiversity conservation
  • Climate change adaptation
  • Disaster risk reduction

Literature info

  • Grey literature
  • Peer reviewed
Case methodolgy reported