|Environment and development
in coastal regions and in small islands
A report with the above title was issued in December 1996 by the University of Puerto Rico Sea Grant College Program (UPR/SGCP) under the authorship of Dr. G. Cambers. This study is part of the UNESCO/CSI-UPR/SGCP-sponsored project "Coast and Beach Stability in the Lesser Antilles" (COSALC). The Executive Summary of the report is given below.
1. EXECUTIVE SUMMARY
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 island's heritage.
Tropical Storm Iris and Hurricanes Luis and Marilyn passed through the eastern Caribbean Islands within the three week period, 26 August to 16 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, 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 UNESCO and is co-sponsored by the University of Puerto Rico Sea Grant College Program (UPR/SGCP). 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.
For more information, contact:
Dr. Gillian Cambers
Project Coordinator, COSALC
University of Puerto Rico
Sea Grant College Program
P.O. Box 5000
MayagŁez, Puerto Rico 00681-5000
Tel: (787) 932-3585
Fax: (787) 265-2880
UNESCO-CSI, fax +33-1-45685808, e-mail: firstname.lastname@example.org
UNESCO PORT OF SPAIN 0018096220536, Mr. W. Wiltshire (Head of Office.)
c/o UNDP POBox 812,19 Keate Street
PORT OF SPAIN
TRINIDAD AND TOBAGO
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