Environment and development in coastal regions and in small islands

Beach Erosion in Nevis

Background

Nevis' beaches are essential to the island’s 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 fine 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 passed close to Nevis in September 1995, beach erosion was a problem at several sites. For instance, Nevis' beautiful three-mile (5 km) Pinney's Beach had been eroding since the early '70s. Every few years, another row of palm trees disappears into the sea, and Pinney's Beach Hotel now juts out into the sea, forming a headland. At Indian Castle, sand mining has destroyed what were once extensive sand dunes. And along the north coast at Nisbett, groynes and jetties have been built in order to stabilize the beach and slow down the erosion process.

In 1988, Nevis joined a regional programme know as COSALC (Coast and Beach Stability in the Lesser Antilles). This programme is sponsored by UNESCO and the University of Puerto Rico Sea Grant College Program. As part of COSALC, beaches are measured on a regular basis in Nevis by the following agencies:

* The Nevis Historical & Conservation Society,
* The Fisheries Division, Ministry of Agriculture,
* The Physical Planning Unit, Department of Planning and Development, Premier's Ministry.

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

Information about changes on Nevis' beaches is available at the research library of the Museum of Nevis History, Hamilton House. The data base on beach changes in Nevis extends back to August 1988.

The effects of recent hurricanes on Nevis' beaches

Two major hurricanes have had a major impact on Nevis since monitoring started in 1988. On the 18th and 19th of September 1989, Hurricane Hugo, a major category-four hurricane. passed 40 miles (64 km) south of Nevis. Then, on September 4-6 of 1995, Hurricane Luis, another category-four hurricane, passed 50 miles (80 km) east of Nevis: The beaches were seriously eroded, and nearshore marine communities were tom apart. On some beaches, dead sea grass formed "carpets" up to 4 ft. thick!

The damage was enormous. Not only the beaches, but dunes behind the beaches, and other coastal lands were greatly eroded. Buildings behind the beach were damaged. Prior to Hurricane Luis, a sandy beach extended 65 ft (20 m) in front of the Four Seasons Hotel at Pinney's Beach. But Hurricane Luis left the restaurant and swimming pool at the sea's edge.

When the Sandpipers Restaurant of Pinney's Beach was completed in August 1995, it was positioned 120 ft (37 m) from the water's edge. One month later, the restaurant was located within the sea!

Beaches along the north and west coasts were severely eroded. However, there was considerable variation between beaches. For instance, on the west coast, Mosquito Bay was only slightly damaged, while east of Hurricane Hill, less than 1 mile away, all sand was stripped from the beach, leaving only a bare rock platform.

In the weeks following Hurricane Luis, the beaches and dunes were re-surveyed. After analysing the data, it appears that the dune or land edge has retreated an average of 17 ft (5 m) inland as a result of Hurricane Luis. This is a very serious loss.

Following Hurricane Luis, the beaches have begun to rebuild as some of the sand moves back onshore. However, the land's edge - and the beaches - are now further inland. Nevis is shrinking as coastal land is lost, and the loss may be permanent. For beaches heavily eroded during Hurricane Hugo in 1989 have still not grown back to pre-hurricane levels.

Sandpipers Resaurant at Pinney’s Beach, October 1995

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 resumed to the beach system. This same wave action also damages coral reefs and sea grass beds. Coral and sea grass ecosystems normally supply and stabilize sediment, providing the beaches with natural protection from wave action.

Other factors causing erosion:

1. Sand extraction from beaches and dunes is a major cause of erosion. Every sand dune is a reservoir of sand that has taken decades to form, and can supply the beach during and after events such as hurricanes. Dunes should be conserved, not mined.

After Hurricane Hugo in 1989, extensive sand mining took place as rebuilding began. But extraction of sand from coastal systems reduces a beach's natural ability to recover. In 1995, Hurricane Luis caused less damage to buildings on the island, so less sand mining took place immediately afterwards. However, sand mining continues to be a serious problem on Nevis' beaches.

2. Pollution and boat anchors damage coral reefs, which supply Nevis' beaches with sand. As the reefs are damaged, they provide us with less sand, and their ability to protect our beaches from high wave energy is greatly reduced.
3. Winter storms in the North Atlantic generate high swell waves, which especially affect the north, east and west coasts of Nevis.
4. Although official information on sea level changes in Nevis 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. All sea defences should be carefully designed.

Groyne at Nisbett, August 1988. Sand has accreted on one side of the groyne (in the foreground) but the other side, the coastline has eroded inland.

When can we expect another hurricane?

Nobody knows the answer to this question. 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 Hurricanes Hugo and Luis.

We need to plan the development of the coasts very carefully so that buildings are a safe distance back from the beach. This way, our beaches will have space to change naturally, and will thus be better preserved.

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. Consult the Department of Planning and Development before designing or beginning any construction activity.
   
3. Seek alternatives to beach sand for construction.
   
4. Keep beaches and coastal waters free of pollution. (This includes our guts and other inland resources!)
   
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 coastal vegetation, including trees, shrubs, vines and grasses. When we clear land without saving these plants, an increased amount of eroded soil washes onto the coral reefs, damaging and killing them.
   
7. Plant trees, especially deep rooting species, for shade, beauty and the stability of our beaches.

	Four Season’s Hotel at Pinney’s Beach, August 1995
	Same view one month after Hurricane Luis in October 1995

For more information, contact...

The Nevis Historical and Conservation Society: (869) 469-0408 or 469-5786

The Fisheries Division: (869) 469-5521

The Physical Planning Unit: (869) 469-5521

COSALC Coordinating Centre, Puerto Rico: (787) 832-3585; fax: (787) 265-2880

and/or

UNESCO-CSI: csi@unesco.org

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