Environment and development
in coastal regions and in small islands
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Wise practices for coping with beach erosion: St Lucia

Fisheries Department, St Lucia
Physical Planning Department, St Lucia
University of Puerto Rico, Sea Grant College Program
Caribbean Development Bank
UNESCO Environment and Development in Coastal Regions and in Small Islands

FORCES TO BE RECKONED WITH

Beaches are continuously changing – from day to day, month to month and year to year – as the natural forces of wind and water meet the land. These changes, which have been taking place for millions of years, are linked to variations in wind, waves, currents and sea level height.

But it is not just the natural forces that change the beach, humans have a big role to play in this process as well, through mining stones and sand from the beaches and dunes, cutting and clearing coastal vegetation, polluting and damaging coral reefs, and constructing buildings and walls too close to the sea.

Changes in the beaches affect everyone. The coast is a place we are attracted to for recreation, sports and simple enjoyment. In addition, it provides a source of employment for many people. This constantly changing and hazard-prone coastal environment is also where the greatest financial investment is concentrated, as large tourism properties and establishments continue to be attracted towards St Lucia’s shores. Tourism is a driving force in St Lucia’s economy so the state of its beaches is of major importance.

Natural forces  

  • Hurricanes and tropical storms, occurring between June and November, cause dramatic beach changes usually resulting in serious beach erosion.
  • High waves during 'winter' months resulting from storms in the North Atlantic Ocean, and known as swell waves, or locally as ‘groundseas’, often cause erosion, especially on the sheltered leeward coast.
  • Sea-level rise, which is a long-term factor, taking place very slowly over decades causes shorelines to retreat inland.  

Since 1995, the Atlantic Basin (including the Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico) has entered a more active hurricane cycle, which may continue for more than 20 years.  

Hurricane frequency between 1990 and 1999 in the Atlantic Basin

Source: Gray et al. http://typhoon.atmos.colostate.edu/forecasts/1999/nov99/ 

In the Atlantic Basin the number of really severe hurricanes (categories 3, 4 and 5) increased from one per year (1990 –1994) to four per year (1995 – 1999).

Human forces

Building on the
beach is an 
unwise practice
which interferes
with natural sand movement,
Reduit Beach,
1990

  • Removing sand and other materials from beaches and adjacent areas for construction purposes causes erosion and the loss of beaches and coastal lands, destroying the natural heritage of the coast and reducing the vibrancy of the tourism industry.
  • Building too close to the beach interferes with the natural sand movement and may impede beach recovery after a serious storm or hurricane.
  • Badly planned sea defences may cause the loss of the beach, and of neighbouring beaches.
  • Pollution from human activities on the land may damage coral reefs and seagrass beds; these biological systems protect, and provide sand to the beaches.
  • Removing vegetation from coastal areas destabilises beaches; and clearing sites inland results in increased soil and dirt particles being washed offshore and smothering coral reef systems.

***********

WHATS HAPPENING WITH ST LUCIA'S BEACHES?


Beach monitoring
in progress at
Malgretoute, 1995
 

In order to manage these changes, St Lucia’s beaches have been monitored since 1995 by the Fisheries Department, who measure the beach slope and width at regular intervals at numerous sites around the island

 
Winter swells at
Reduit Beach
seasonally erode
the beach and
threaten
beachfront
buildings, 1995

Location of monitored beaches in St Lucia

***********

SAND IN, SAND OUT  

Beaches change from season to season and from year to year. For example along the western side of the Causeway which joins Pigeon Island to the mainland, erosion has been taking place since the Causeway was constructed in the 1970s. Monitoring results show that between 1990 and 1995 the edge of the Causeway retreated inland 10 m. 

BEACH PROFILE
Pigeon Island Causeway. Beach erosion

The western side of the
Pigeon Island Causeway
has been eroding since
it was first constructed,
December 1995

 

The erosion is also
evident at the adjacent
Reduit Beach,
December 1995

 

***********

DUNES AS RESEVOIRS OF SAND

Dunes are an important part of the coastal system and function as reservoirs of sand, supplying beaches during storms and protecting coastal land from flooding. Many dunes have been damaged or destroyed over past decades in St Lucia as a result of sand mining and the construction of buildings.

These vegetated dunes
at Cas en Bas protect
the land behind the
beach from flooding,
1989

Detail of
dune vegetation

Clearing dunes and
their vegetation
destabilises the
beach and the
coastal system,
Point Sable, 1989

 

Mining sand from dune systems
here at Point Sable destroys the
protective seagrape
vegetation
and causes erosion, 1989

 

***********

HERE TODAY, GONE TOMORROW  

St Lucia has been impacted by several tropical storms and hurricanes during recent years. These events cause considerable damage to coastal areas, as well as eroding beaches and dunes. In the months and years after the hurricane event, the beaches recover to some extent, but not usually to pre-hurricane levels.

In 1995, St Lucia’s beaches were impacted by Tropical Storm Iris and Hurricane Luis. At Vigie Beach there was erosion and the beach narrowed by 11 m.

BEACH PROFILE
Vigie Beach. Beach erosion

  

Vigie Beach after
Hurricane Luis,
December 1995

Debris covering the
beach at Fond D’Or
after Tropical Storm
Debbie in 1994

***********

WISE PRACTICES FOR A HEALTHY BEACH


Grasses, vines
and seagrape
here at Anse Ger
help to stabilise
the beach and
dunes, 1994

    

The state of the beach affects everyone's lives. There are no simple or universal solutions to shoreline erosion, since there are often several factors, both human and natural, contributing to the problem at a particular beach. Each beach behaves differently, so it is advisable to find out as much information as possible about a particular beach before taking any corrective action. It is necessary to consult the Physical Planning Department before undertaking any action at a beach.

Some forces of change, such as hurricanes and winter swells are natural, and there is little we can do to stop them, yet there are ways we can help to slow down the rate of erosion:

  • Planning new development so that it is a ‘safe’ distance behind the beach will reduce the need for expensive sea defence measures in the future.

  • Revegetating dunes with native vegetation e.g. grasses and vines, and planting beach areas beyond the reach of storm waves with salt-resistant, deep-rooting trees, such as seagrape.

  

Ensuring new
development is a
‘safe’ distance
from the dynamic
beach zone, helps
conserve the
beach and
the buildings

 


  

Buildings close to the beach are vulnerable to erosion

Buildings at a safedistance from the beach are less 
vulnerable to erosion

  

Extracting pumice for 
construction material 
reduces the need to mine 
sand from beaches,
Black Bay, 1989

 

Only a narrow beach exists in front of this retaining wall at 
Reduit Beach, April 1998

   


Groynes, as seen
here at Wyndham
Bay in 2001,
result in sand
build-up on one
side of the
groyne...
  • Resorting to ‘hard’ engineering structures such as retaining walls, seawalls, revetments and bulkheads, only when there is a need to protect beachfront property from wave action. Such structures, even with careful design, result in the loss or narrowing of the beach over time.

  • Considering all other beach enhancement measures such as offshore breakwaters, groynes and beach nourishment (placing sand from the offshore zone or from an inland source on the beach) at a particular site. All such measures require careful design and environmental impact assessments, so always first consult the Physical Planning Department.

  

…and erosion on
the other side

 

Recommended coastal development setback distances along the north-west coast of St Lucia

l
l
15m (50ft)
24m (80ft)
l
l
36m (120ft)
49m (160ft)
MEASURED FROM VEGETATION LINE
Key to the beach numbers
1
2
3
4
Le Sport
Anse Becune
Causeway
Gros Islet
Reduit Beach 
6
7
8
9
10 
Trou Gaston
Trou Ya
Cuti Cove
Labrellote Bay
Marisule Beach 
11
12
13
14
15 
Choc Beach 
Vigie Beach
Tapion
La Toc Bay
Anse Fere
16
17
18
19
20 
Marigo
Roseau Bay
Anse Pilori
Trou l’Oranger
Anse La Raye

***********

WISE PRACTICES CHECKLIST
Plan for existing and future coastline change by positioning all new development (large and small) a ‘safe’ distance landward of the vegetation line (consult the Physical Planning Department for information on ‘safe’ distances).  
Ensure the physical planning process is fair, equitable and transparent.
Review and carefully consider ALL options when planning ways to slow down the rate of coastline change, these should include planning, ecological and engineering measures.
Monitor the rate of coastline change and share the findings with all other stakeholders.

Coordinate an integrated approach to beach management, by ensuring that individuals, groups and agencies work together.

Promote the concept of coastal stewardship and civic pride.

Respect the rights of all beach users.
Provide for dedicated public access lanes to all beaches, and where appropriate provide facilities for beach users (e.g. parking, safety measures, sanitary facilities).

Stop the mining of sand from beaches and dunes, ensure that mining sites are restored after use, and investigate alternative building practices.

Conserve and restore vegetative cover, both adjacent to the beach in order to stabilise the sand, and further inland to reduce sediment reaching the reefs and seagrass beds.

 

For more information on shoreline 
change in
ST LUCIA consult:

Fisheries Department, Fisheries Complex
Castries, St Lucia
T: +1 758 452 6172, 452 3987
F: +1 758 452 3853
E: deptfish@slumaffe.org

Physical Planning Department
Ministry of Planning and Development
PO Box 709, Castries, St Lucia
T: +1 758 451 8746
F: +1 758 452 2506
E: gisunit@hotmail.com

For more information on shoreline 
change in the
CARIBBEAN consult:

Coping with Beach Erosion
by Gillian Cambers
UNESCO Publishing, 1998
ISBN 93-3-103561-4  

 

This booklet is a result of 
co-operation between UNESCO, 
the Caribbean  Development 
Bank and St Lucia's  
Governmental agencies  

Illustrations: Barbara Navi – Photographs: Gillian Cambers – Design: Eric Loddé

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