The national treasure that is Seven Mile Beach is diminishing before our eyes, with beach erosion at the southern end a quickly growing threat to its very existence. The Caymanian Times speaks with Lauren Dombowsky, the Manager at the Environmental Management Unit with the Department of Environment, about the steps needed to save this precious natural asset.
The erosion of Grand Cayman’s Seven Mile Beach is evident for all to see, with a swathe of once walkable coastline now submerged under the ocean. Lauren Dombowsky confirms that there is little doubt that many sections of Seven Mile Beach and numerous other coastlines of the Cayman Islands are under increasing threat from a wide range changing environmental factors, sea level rise being one of the most obvious impacts.
“Increases or decreases in storm events can also drastically impact sediment transport systems that are responsible for eroding or replenishing a beach,” she said.
However, other, less obvious, or less well understood impacts also exist and include the changes in the offshore environment because of the loss of coral reef structure and habitat.
“Coral reefs and the creatures that inhabit them are a significant source of the sand that is found on Cayman’s beaches, so as those systems are degraded so, too, are the sources of new sand diminished. Additionally, well-developed offshore reef habitats are important in buffering coastlines and beaches from large waves, so as reefs degrade, shores are more exposed,” she explained.
A host of other issues also contribute to the problem, including Increases in nutrients entering the water from upland sources that also enable marine algae to thrive that quickly outcompete and replace the slower growing corals and coralline algae, which are important producers of sand. Loss of seagrass habitats and increases in Sargassum stranding are also a significant threat to coastlines and beach stability. Ocean acidification from increased dissolved CO2 has the potential to interrupt calcification processes employed by many marine organisms, corals included, that also contribute to the white sand beaches found around Cayman.
The human touch
Ms Dombowsky said, given the host of environmental processes that contribute to beach stability, there are also numerous human-led impacts that exacerbate the disruption of the already delicate balance of beach dynamics.
“Seawalls and structures built or inappropriately sited in or close to the water are all too often the cause of significant beach loss or prevent a beach from recovering after a storm event,” she said. “The loss of the upland beach system to hard structures and buildings means that sand reserves that once were available to replenish a beach are now locked out of the system or have been replaced with other types of structural fill. The removal of natural beach vegetation that once helped slow down sand loss during erosional storm events can also mean wind and rain are now contributing the removal of sand.”
National policy needed
Seven Mile Beach is a national asset. It is not possible for private individuals or businesses to resolve the erosion issues and rehabilitate the beach on their own, Ms Dombowsky believes.
“Seven Mile Beach is a dynamic system which is constantly changing. What happens on one property can impact what happens on another property, negatively and positively. Aside from minor renourishment projects within a property boundary, there is not much else than can be done on an individual scale. There needs to be a National Policy adopted by the elected government and fed back to agencies including the National Conservation Council and the Central Planning Authority to guide decision-making with respect to approval of new structures on the active beach,” she affirmed.
Government needed to decide on whether they would intervene or not along the southern part of Seven Mile Beach to repair the problems that have already occurred.
“If the government does not intervene, then we would have to accept that there would likely never be a consistent beach on the southern end of Seven Mile Beach,” Ms Dombowsky said. “We, as a country, would have to accept the impacts to our tourism product, any potential liability from anyone negatively affected, and permit properties without seawalls to build them (without impacting the Marine Protected Area) to protect their structures from storms.”
If the government did intervene, then there were many ways that this could be a joint undertaking between the private sector, such as voluntary cost-sharing or a Special Assessment fee – to ensure that everyone paid their fair share.
Beach erosion needs to be addressed for environmental, social, and economic reasons.
“Turtles nest on our sandy beaches and beaches are also home to other animals like crabs. They are subjected to coastal squeeze, where because of sea level rise and coastal development, the amount of beach habitat shrinks,” Ms Dombowsky explained.
In addition, with smaller beaches and a rising population, there would be more user conflict between beach vendors, watersports operators, tourists, hotels, and locals.
“Seven Mile Beach is the most well-known and iconic visitor attraction in Cayman and we risk harming our image if no action is taken,” she said.
Last year, the Ministry of Sustainability and Climate Resiliency was preparing a proposal for a Coastal Setback Reference Line last year, a fixed line based on long-term scientific data which would be the line where future setbacks for development would be measured from. This would prevent future development from further impacting the beach provided that reasonable coastal setbacks are also in place and there was a consistent policy applied by the planning officials of all proposed coastal development having to meet at least the minimum specified setbacks, she advised.
“It would be a more sensible way to plan coastal development as it is not proposed to change land ownership or access, just provide a realistic and pragmatic line rather than relying on a rapidly changing boundary like the Mean High Water Mark,” Ms Dombowsky said.
Managed retreat is treated as contentious by those who do not understand what is involved, she worried.
“Attempting to ‘hold the line’ in many places is a losing battle, so if we do not have managed retreat, we will end up with unmanaged retreat due to damage from storms, changes in insurance costs, market, and economic losses. Managed retreat involves strategic planning around how we can adapt to coastal hazards.”