Environment and development in coastal regions and in small islands

Beach erosion in Antigua-Barbuda

Coast and Beach Stability in the Lesser Antilles (COSALC) project sponsored by UNESCO and the University of Puerto Rico Sea Grant College Program

Background

Antigua-Barbuda's beaches are essential to economic, environmental and social well being. They:

• protect coastal lands from wave action, especially during hurricanes,
• provide an important recreational resource for tourists and local residents,
• provide habitats for coastal plants and animals, and nesting sites for sea turtles,
• are a source of aggregate for construction,
• are an aesthetically pleasing - and culturally important - part of the environment.

However, beach erosion is a growing cause for concern. Even before Hurricane Luis impacted the country in September 1995, beach erosion was a problem at several sites. For instance, at Dickenson Bay, one of the most popular tourist beaches of northwestern Antigua, the beach eroded at a rate of 3 ft per year (0.9 m) between 1991 and 1994. In Barbuda, between the dock and the former Dulcina Hotel, fallen trees, exposed tree roots and narrow beaches could be observed by all.

Remnants of tree roots in the sand at Dulcina, Barbuda, are evidence of erosion that took place before Hurricane Luis.

In 1991, Antigua-Barbuda joined a regional project entitled 'Coast and Beach Stability in the Lesser Antilles' (COSALC).

As part of COSALC, the beaches are measured on a regular basis by the following agencies:

• The Fisheries Division, and
• The Development Control Authority.

Every three months, personnel from these agencies use standard surveying techniques to measure the area and width of Antigua-Barbuda's beaches. Then they analyze the data using a computer spreadsheet programme. The trends observed help determine whether a beach is eroding (getting smaller) or accreting (gaining in size).

Beach monitoring at Dickenson Bay, Antigua, in 1991.

Information about changes in Antigua-Barbuda's beaches is available at the Fisheries Division. Data on beach changes in Antigua goes back to September 1991; and data on beach changes in Barbuda extends back to July 1995.

The effects of Hurricane Luis on the beaches of Antigua-Barbuda

Between the 4th and 6th of September 1995, Hurricane Luis, a huge, category-four hurricane, passed directly over Barbuda. All of Antigua-Barbuda's beaches were eroded by hurricane force waves. Underwater damage was evident for all to see, as beaches were carpeted with dead sea grass and debris torn from coral reefs.

The damage to coasts and beaches was enormous. Even coastal lands and dunes behind the beaches were eroded. The accompanying graph shows the beach at Runaway Bay before and after the hurricane. A low, grassy sand dune behind the beach once measured 5 ft (1.5 m) high and 46 ft (15 m) wide. Hurricane Luis totally eroded this dune, leaving the hotel cottages without a beach. This scenario was common on Antigua's coasts.

At Fort James, a few patches of tarmac on the beach are all that remains of what was once a road protected by a boulder revetment. At Darkwood Beach, sand several feet thick buried the road, and now ledges of beach rock out at sea mark where the beach used to be.

In Barbuda, the erosion was even more severe. At Cocoa Point, the dune edge was eroded 66 ft (20m) inland! The sand bar enclosing the Lagoon at Codrington was breached in several places, allowing seagoing vessels to enter the Lagoon!

The beaches and dunes were re-surveyed during the weeks following Hurricane Luis. After analysing the data, it appears that the dune or land edge retreated an average of 23 ft (7 m) as a result of the hurricane. This is a very serious loss for Antigua-Barbuda, for our dunes represent a reservoir of sand that has been built up very slowly over the years. Besides protecting the beaches and the land behind them, sand dunes also help to supply the beaches with sand during - and after - storms and hurricanes.

Following the hurricane, the beaches began to rebuild as some of the sand was moved back onshore. However, the dune edge - and our beaches - are now further inland. Antigua-Barbuda is shrinking, as coastal land has been lost, perhaps forever. For on other islands, such as Dominica and Nevis, beaches heavily eroded during Hurricane Hugo in 1989 never returned to pre-hurricane levels.

Beach profile before and after Hurricane Luis.

Are hurricanes the only cause of beach erosion?

While hurricanes are not the only cause of beach erosion, they are certainly a major factor. The high waves caused by hurricanes move sand into deep water offshore, where it can never be returned to the beach system. This same wave action also damages coral reefs and seagrass beds. Coral and seagrass ecosystems normally supply and stabilize sediment, providing beaches with natural protection from wave action.

Other factors causing erosion:

1. Sand extraction from beaches and dunes is a major cause of erosion. Heavily mined sites such as Fort James and Darkwood Beach were especially vulnerable to the high waves of Hurricane Luis.
   Extensive sand mining took place after the hurricane under the pretext of "clearing and cleaning" beaches and coastal areas. This extraction of sand from the coastal systems reduces any natural beach recovery that might otherwise take place. The mining of sand from beaches and dunes is a serious problem in Antigua-Barbuda.
2. Pollution and boat anchors damage coral reefs, which supply nearly all of Antigua-Barbuda's beach sand. As the reefs are damaged, they provide us with less sand, and are less able to . protect our beaches from high wave energy.
3. Winter storms in the North Atlantic generate high swell waves, which especially affect the north, east and west coasts of Antigua-Barbuda.
4. Although official information on sea level changes in Antigua-Barbuda is not yet available, scientists concur that sea level rise related to the "greenhouse effect" also causes beach erosion.
5. Some sea defence structures may result in beach erosion. Groynes and jetties may result in accretion on one side, while causing erosion on the other. Sea walls protect the land from erosion, but they may also cause the beach to disappear. All sea defences should be carefully designed.

Before Hurricane Luis, a road protected with boulders ran alongside this beach at Fort James. In 1996 only a few patches of tarmac remain.

When can we expect another hurricane?

Nobody knows the answer to this question. Prior to "Luis," the last major hurricane to affect Antigua-Barbuda was Hurricane Donna in 1960. But this does not mean that we can rest easy for the next 35 years. Scientists predict that we are entering a period of 20 to 30 years of more intense hurricane activity. These predictions are based on a study of weather patterns and climate records over the past century. Tropical storms and hurricanes passing over other islands may also affect us and our beaches, as we saw during Tropical Storm Klaus in 1984 and Hurricane Hugo in 1989.

We need to plan the development of our coasts very carefully so that our buildings are a safe distance back from the beach. This way, our beaches will have space to change naturally, and will thus be better conserved. Experience at Dutchman Bay and other sites has shown that it is very expensive to try and repair the damage caused by beach erosion. It is far more cost effective to plan for beach erosion by placing new buildings well behind the active beach zone.

What can we do about beach erosion?

1. Be aware! While beaches "come and go" as part of a natural seasonal cycle, long term erosion is also occurring.
2. Make allowances for hurricanes and beach changes when planning new coastal developments. Set new buildings well back from the beach. Consult the Development Control Authority before planning or commencing any construction activity.
3. Seek alternatives to beach sand for construction.
4. Keep beach and coastal waters free of pollution. (Marine pollution often originates as inland-generated grey water, sewage, pesticides and sediments!)
5. Preserve sand dunes, especially primary dunes, in their natural state. Avoid building on dunes. Where dunes are eroding, help to stabilize them with vegetation, and construct wooden walkways to prevent wear and tear by beachgoers and hikers.
6. Preserve our coastal vegetation, including trees, shrubs, vines and grasses. When we clear land without saving these plants, an increased amount of eroded soil washes onto our coral reefs, damaging and killing them.
7. Plant trees, especially deep rooting species, for shade, beauty and the stability of our beaches.

During Tropical Storm Klaus in 1984, the beach at Darkwood was seriously eroded, and the highway running behind the beach was endangered.

For more information, call ...

The Fisheries Division: (268) 462-1213, 462-6106, or 462-1372.
The Development Control Authority: (268) 462-6427, 462-2038, or 462-4534,
COSALC Coordinating Centre, Puerto Rico:(787) 832-3585; fax: 265-2880.

and/or

UNESCO CSI, email: csi@unesco.org

Local/regional contact

TRINIDAD AND TOBAGO
PORT OF SPAIN
Tel. 0018096220536, Mr. W. Wiltshire (Head of Office)
c/o UNDP POBox812, 19 Keate Stree
PORT OF SPAIN
TRINIDAD AND TOBAGO
Fax. 18096231658, Telex 22257 UNDP WG
Covers: Aruba, Guyana, Neth, Antilles, Suriname, Trinidad and Tobago

Published by: Sea Grant Printers, 1996
Amended for the CSI home page in February 1997.

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