Cayman Islands communities receive vital protection worth over £60 million annually from coral reefs, mangroves and natural coastal defences against severe flooding, according to recently published research.
The study (JNCC – UK Overseas Territories Report 6. Model development to assess the vulnerability of the Cayman Islands to storm surge and inland flooding and the role of natural capital in mitigating the impacts: Phase 2) reveals how the islands' natural capital provides essential flood protection services equivalent to about 30% of the value added by hotels and restaurants sector to the islands’ annual economic contribution. Natural vegetation across the islands intercepts rainwater and reduces peak flood flows, while coastal reefs break up destructive wave energy before it reaches populated areas.
Without healthy reefs and coastal ecosystems, flood damage costs would increase dramatically during major storms. The comprehensive assessment, supported by the UK Government's Conflict, Stability and Security Fund, examined flooding vulnerability across the Cayman Islands. Advanced computer models showed that degraded coral reefs and damaged mangroves would allow significantly deeper flooding during hurricanes, with water levels rising by up to an extra 75 centimetres in some coastal areas.
Twenty-eight priority nature-based solutions have been identified to strengthen the islands' natural flood defences. These include the establishment of marine protected areas, protection of terrestrial habitats such as mangroves, wetlands and woodlands, alongside traditional engineering approaches such as the building of channels and trenches.
Southwest George Town and North Sound coastal developments face particular flood risks, the study found. The research developed practical tools enabling Cayman Islands Government staff to model future flood scenarios and assess the economic impact of environmental changes. Training workshops equipped local teams with skills to use flood modelling software and economic assessment methods for long-term planning.
The computer models developed in this report were also used by the Department of Environment – with support from JNCC – to model the impacts of flooding in the area of South Sound in more detail, the results of which have been published in a separate report (JNCC – UK Overseas Territories Report 9. Understanding the increase in flood risk within South Sound (Grand Cayman) under various development scenarios). This second study examined the increasing flood risk in the South Sound area under various development scenarios and the effect of mangrove loss and subsequent filling for development leading to water displacement and flooding in other urban areas.
The work builds on earlier work led by JNCC in estimating the economic value of flood protection services in the Cayman. This information will be used by the Cayman Islands Government in developing plans, policies and procedures which increase resilience to natural disasters and enhance on-island capability in preparing for and recovering from the impact of extreme storm events.
This research demonstrates the critical economic value of environmental protection in building climate resilience, supporting both community safety and economic security as extreme weather events become more frequent and severe.
The study was published by WSP Environment and Infrastructure Solutions UK Ltd with JNCC and in collaboration with several departments of the Cayman Islands’ Government, including Hazard Management Cayman Islands and the Cayman Islands Department of Environment.
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