in coastal regions and in small islands
Hurricane impact on beaches in the eastern Caribbean Islands 1989 - 1995
Conservation of beaches is fundamental to the economic and
social well being of all citizens of the eastern Caribbean Islands.
Tourism, the region’s primary
industry, is dependent on the beaches, which form an integral part of each
Tropical Storm Iris and Hurricanes Luis and Marilyn passed
through the eastern Caribbean Islands within the three week period, 26th August
to 16th September, 1995. Hurricane
Luis was a category 4 storm and Hurricane Marilyn a category 3 storm.
All the islands, from Grenada to Puerto Rico were impacted by these
storms, however, the damage was most severe in the islands from Dominica
northwards. In 1989, Hurricane
Hugo, another category 4 storm, had passed through the eastern Caribbean
Islands, along a similar track to the 1995 storms.
Since 1985 many of these islands have been participating
in a regional programme, COSALC (Coast and Beach Stability
in the Lesser Antilles) which was initiated by the United
Nations Educational, Scientific and Cultural Organization (UNESCO) and is
co-sponsored by the University
of Puerto Rico Sea Grant College Program.
COSALC has been assisting the smaller islands with the management of
their beach resources and in each island monitoring programmes had been established
to determine rates of beach change - erosion and accretion.
Using these beach change databases, this report assesses the impact of the 1989 and 1995 hurricanes on the islands’ beaches. The effects of Hurricane Hugo in 1989 were determined in Dominica, Nevis and the British Virgin Islands. The effects of the 1995 hurricanes were assessed in Anguilla, Antigua-Barbuda, Nevis, St. Kitts, Montserrat and Dominica.
The 1989 and 1995 hurricanes caused severe beach erosion in the islands, beach volumes decreased on average by 28% following the 1995 storms. There was, however, considerable variation from beach to beach, some beaches actually accreted, while others were totally stripped of sand. The hurricanes also caused retreat of the land edge or sand dunes behind the beach. This coastline retreat is viewed as a “permanent” change. Within 40 km of the centre of Hurricane Luis, the average coastline retreat varied between 5 m and 18 m, the maximum recorded coastline retreat was 30 m. Between 40 and 180 km of the centre of Hurricane Luis the coastline retreat was between 2 and 5 m.
There was a clear relationship between the proximity of
the hurricane centre and the amount of beach erosion.
Nevertheless, other factors which influenced the severity of the erosion
include the characteristics of a particular hurricane, coastline shape, width of
the offshore shelf and local features such as coral reefs.
Similar magnitudes and patterns of beach erosion occurred when islands
were impacted by both the 1989 and 1995 hurricanes.
Major beach recovery took place, particularly within eight
months of Hurricane Luis. Analysis
of data from Hurricane Hugo showed that beach recovery continued at a slower
rate for two to three years after the hurricane, and that the beaches did not
recover to their pre-hurricane levels.
In view of predictions of increased hurricane activity in the next two decades, it is recommended that coastal development setbacks be reviewed in each island and if necessary amended. New setback guidelines for Anguilla which incorporate several factors including the impact of a category 4 hurricane could serve as a framework for the region. Citizens and special interest groups particularly those associated with the tourism industry, need to be informed about the likely impacts of hurricanes on their beach resources, the post hurricane beach recovery process and measures that can be taken to enhance the natural beach recovery and protect coastal property. Information exchange, forward planning and training are the key components needed to reduce the impacts of hurricanes on the vital beach resources of the eastern Caribbean Islands.