Beyond increasing the risks of natural disasters to small island states, the rise in mean sea level (MSL) is among the main causes of erosion in many coastal areas across the planet.
This harmful process affects the environmental quality of many beaches on the western and southern coasts of the United States, Jamaica, Mexico, the Dominican Republic, Spain, South America and the Black Sea, to cite a few examples, where prejudicial natural conditions have combined with the inappropriate actions of human beings.As reflected in one of the chapters of the book, Impact of Climate Change and Adaptative Measures in Cuba, presented recently in Havana and including the work of specialists from 30 institutions and agencies, worldwide MSL grew at an average rate of 3.1mm between 1993 and 2003, while an increase of 22 to 85 centimeters by 2100 is predicted.
This change is attributed to thermal expansion of the oceans and the loss of the ice in glaciers and polar icecaps. It is worth mentioning that the increase will not occur uniformly across the world’s different geographical areas, as there are other contributing factors, including vertical land movement (VLM).
RESTORING SAND DUNES
Studies conducted as part of the Macroproject on Coastal Hazards and Vulnerability for the years 2050 and 2100, by researchers from the Institute of Oceanography at the Ministry of Science, Technology and Environment, in collaboration with various other institutions, has confirmed that the erosion of Cuban beaches is widespread, with a coastal erosion rate estimated at 1.2 meters per year.
Doctor of Geographical Sciences, José Luis Juanes, head of the Coastal Processes Department at the institute, explained to Granma that in some parts of the country there are reports of an erosion rate of over 2.5 meters per year, similar to that recorded for the rest of the Caribbean region.
He indicated that the cause is in large part the rising sea levels surrounding Cuba (between 1996 and 2009 the average rate rose to 1.43mm per year in the archipelago), combined with extreme erosive events caused by the onslaught of weather phenomenon and a deficit in terms of sources for the production of sand.
Add to this the negative actions of human beings in the past, specifically construction works on top of natural sand dunes, the extraction of sand, as well as the incorrect design and location of breakwaters and inner harbors.
Dr. Juanes explained that as part of the studies conducted, the national tally of beaches was updated, with the number rising to 424. Of 257 technically evaluated, 86% showed signs of erosion.
The most significant cases were observed on Guanimar, Majana, Cajío, Mayabeque Caimito, La Pepilla, Tasajera and Rosario beaches, located in the provinces of Artemisa and Mayabeque, which have suffered from ruthless human activity for many years, and were affected by severe surf generated by hurricanes Gustav and Ike in 2008, leaving beaches virtually devoid of sand.
Among the main evidence of this process is the existence of numerous fallen and damaged trees in the sea.
Similarly, it is evident that the passage of powerful hurricanes causes coastal flooding which overran sand dunes in various parts of the country. This leads to the transfer of sand towards inner lagoons, causing significant structural changes in the outline of the coast.
According to Dr. Juanes, this may reflect a specific manifestation of the effect of sea level rise, an issue which remains under investigation.
The knowledge accumulated through these studies has allowed for work on the design of forecasting models to assess the response of sandy coasts to rising MSL, as well as the adoption of measures to ensure better protection of our beaches and erosion control.
It is worth mentioning that sand has been artificially supplied in Varadero since 1987, in order to rebuild and maintain the required quality levels of the beach for bathers. Constructions on top of natural dunes have been demolished and the dunes gradually restored.
One of the ongoing projects related to the aforementioned is that aimed at the functional rehabilitation of the sand dunes in Playas del Este, specifically in the area of about 300 meters in front of the Tropicoco Hotel in Santa María del Mar. Over ten thousand cubic meters of sand has been deposited in the area, with beach grasses and boniato having been planted in order to stabilize and prevent the loss of the deposited sand.
Elevated wooden walkways have also been built to avoid trampling of vegetation on top of the dunes, and provide access to the beach.
This work has been extended up to the Itabo river mouth, at the end of the Boca Ciega beach.