ANALYSIS OF BEACH CHANGES IN ANTIGUA AND BARBUDA

Transcription

1 ANALYSIS OF BEACH CHANGES IN ANTIGUA AND BARBUDA Volume 1 Assessment Report June 2003 Prepared by Philmore James Fisheries Division Ministry of Agriculture, Lands, Fisheries Antigua and Barbuda 2003 UNESCO CSI Environment and Development in Coastal Regions and Small Islands UPR SGCP University of Puerto Rico Sea Grant College Program.

2 ANALYSIS OF BEACH CHANGES IN ANTIGUA AND BARBUDA Volume 1 Assessment Report June 2003 Prepared by Philmore James Fisheries Division Ministry of Agriculture, Lands, Fisheries Antigua and Barbuda UNESCO CSI Environment and Development in Coastal Regions and Small Islands UPR SGCP University of Puerto Rico Sea Grant College Program. The Staff of the Fisheries Divisions of Antigua and Barbuda did the collection of data together with members of the Antigua and Barbuda Defense Force/Coast Guard (ABDF/CG). These include: Appleton C. Agustin K. Archibald M. Burnes M. Comacho R DeSouza A. Francis George V. Guishard A. Horsford I. James P. John R. Layne D. Looby G. Lovell T. Morris O. O marde C. Oscar K. Simon H. Williams C. Photographs by Philmore James Fisheries Division, Antigua W. I.

3 TABLE OF CONTENTS Acronyms Definition of Important Terms Executive Summary Introduction Background Tropical Weather Systems affecting Antigua and Barbuda Past Activities Re: Beach Monitoring in Antigua and Barbuda Methodology Results Beach Changes at Individual Beaches Antigua Sites Barbuda Sites Overall Beach Changes: Discussions Recommendations References Appendix Appendix 1. Major Tropical Systems Impacting Antigua and Barbuda List of Tables... List of Figures... ii ii

4 LIST OF TABLES Table 1. Barbuda: Beach Changes Table 2. Antigua: Beach Changes Table 3. Sediment Sizes Table 4 Beach Erosion Hazard Table 5 Barbuda: Individual Beach Changes Table 6 Antigua: Individual Beach Changes LIST OF FIGURES Figure 1 Monitored Beaches in Antigua. 05 Figure 2 Monitored Beaches in Barbuda. 06 Figure 3. Cross-section of a Typical Beach.. 09 Figure 4. No. Tropical Weather Systems affecting Antigua and Barbuda Figure 5. Dune Retreat after a Hurricane. 11 Figure 6. Antigua: Changes in Profile Area, Figure 7. Antigua: Changes in Profile Width, Figure 8. Barbuda: Changes in Profile Area, ii

5 ACRONYMS CDB Caribbean Development Bank COSALC The Project: Coast and Beach Stability in the Caribbean CPACC Caribbean Planning for Adaptation to Climate Change CRIS Coastal Resources Information Systems CSI Environment and Development in Coastal Regions and Small Islands, (UNESCO) DCA The Development Control Authority FD Fisheries Division GIS Geographical Information Systems GPS Geographical Positioning System MCW Ministry of Communications and Works (Public Works) MTE Ministry of Tourism and the Environment NGO Non-Government Organisation OAS Organization of American States OECS Organization of Eastern Caribbean States UNESCO United Nations Educational, Scientific and Cultural Organization UPR-SGCP University of Puerto Rico Sea Grant College Program USAID United States Agency for International Development 1

6 DEFINITION OF IMPORTANT TERMS: Accretion: Accumulation of sand or other beach material due to the natural action of waves, currents and wind; a build-up of sand or other beach material. Back beach: The section of beach extending landwards from the high water mark to the point where there is an abrupt change in slope or material; also referred to as the backshore. Beach The area or zone where the sea interfaces with the coastline. This usually consists of deposits (sand, pebbles, etc,.). Beach nourishment: Artificial process of replenishing a beach with material from another source that is located either inland or is dredged offshore. Beach profile: Side view of a beach extending from the top of the dune line into the sea. Beach recovery: Process whereby accretion takes place at a beach, usually after a major storm or hurricane. Beachrock: Ledges of rock formed within the body of the beach consisting of sand grains cemented by calcium carbonate and formed by chemical processes. Erosion of the sand leaves the beachrock exposed. Beach Segment Any part of a stretch of beach. Berm crest: Ridge of sand or gravel deposited by wave action on the shore just above the normal high water mark. Dredging: Excavation, digging, scraping, drag-lining, suction dredging to remove sand, silt, rock or other underwater sea-bottom material. Dune: Accumulations of wind-blown sand in ridges or mounds that lies landward of the beach and usually parallel to the shoreline. Dunes shift periodically. Ecosystem: Organization of the biological community and the physical environment in a specific geographical area. Erosion: Wearing away of the land, usually by the action of natural forces. Foreshore: Zone between the high water and low water marks. Groyne: Shore protection structure built perpendicular to the shore; designed to trap sediment. Also, groin. High water mark: The highest reach of the water at high tide. It is sometimes marked by a line of debris, e.g. sea grass, pieces of wood, etc, Hurricane: Intense, low-pressure, tropical weather system with maximum surface wind speeds that exceed 118 km/hr (74 mph). Leeward: The lee or sheltered side. Leeward coast: Coast sheltered from the waves. Longshore current: A movement of water parallel to the shore, caused mainly by waves. Longshore drift: Movement of material parallel to the shore also referred to as longshore transport. This results from the action of longshore currents. 2

7 Low water mark: Monitoring: Profile Area: Profile Width The highest reach of the water at low tide. Systematic measurement and recording over time. Cross-sectional area under the beach profile. Horizontal distance across the beach profile, measured from the base of the fixed reference point to the first offshore step. Shore protection structure made with stones laid on a sloping face. Area of the sea-bottom colonized by sea grasses. Revetment: Sea grass bed: Seasonal deposition: Accumulation of sand or other beach material, usually layered, resulting from seasonal variations in coastal processes. Seasonal erosion: Loss of sand or other beach material resulting from seasonal variations in coastal processes. Setback: Prescribed distance landward of a coastal feature from a standard feature (e.g. the line of permanent vegetation), within which all or certain types of development are prohibited. Shore: Narrow strip of land in immediate contact with the sea. Shoreline: Intersection of a specific water height with the shore or beach, e.g. the high water shoreline is the intersection of the high water mark with the shore or beach. Swell: Waves that have traveled out of the area in which they were generated. Topography: Configuration of a surface including its relief and the position of its natural and man-made features. Tropical depression: Organized low-pressure system forming in tropical latitudes with wind speeds of between 37 km/h and 60 km/h (23 mph and 37 mph). Tropical storm: Low-pressure weather system with maximum surface wind speeds between 61 km/h and 118 km/hr (38 mph and 74 mph). Tropical wave: Low-pressure system forming in tropical latitudes with wind speeds of up to 36 km/h (22 mph). Tropical Weather System Wave breakpoint: Wetlands: Windward: Windward coast: In reference to the Caribbean Region, any one of or a combination of the following: Tropical wave, Tropical depression, Tropical storm, hurricane. The point where the waves break. Low-lying areas that are frequently flooded and which support vegetation adapted to saturated soils e.g. mangrove swamps. Side facing the prevailing wind. Coast exposed to wave action as a result of facing the prevailing wind. 3

8 EXECUTIVE SUMMARY The beach is one of the major coastal features that significantly contribute to the physical, social and economic development of Antigua and Barbuda. Between 1996 and 2001, various changes have occurred on a number of beaches. Tropical weather systems, including tropical waves, depressions, tropical storms and hurricanes, have contributed to these changes. For this period, there were four (4) tropical depressions, six (6) tropical storms and ten (10) hurricanes that may have impacted Antigua and Barbuda. This report provides a summary, including quantitative assessments of some of the changes. Volume 2 provides the detailed data and assessment of each beach-monitoring site. The beach-monitoring programme that started in 1991 in Antigua was extended to Barbuda in Figures 1 and 2 show the beaches that are monitored in Antigua and Barbuda. Twenty-five (25) beaches were measured (19 in Antigua, 6 in Barbuda). Both volumes will cover data from in Antigua and from in Barbuda. Previous volumes, prepared by Dr. Gillian Cambers, covered the period The beaches are measured every three months but transportation and other factors have affected the regularity of measurements in Barbuda. At the monitored beaches in Antigua, for the reporting period, there was an average increase in profile area of 0.63 m 2 while the profile width narrowed at a rate of 0.04 m/yr. In Barbuda there was an overall increase, with average profile area and width of 0.47 m 2 and 1.87 m/yr, respectively. For both Antigua and Barbuda, the profile area ranged from m 2 to m 2 while the profile width ranged from m/yr to 5.97 m/yr. Tables 1 and 2 show the average changes in profile area and width for Barbuda and Antigua. Table 1. Barbuda: Beach Changes Beach Change in Profile Area m 2 Change in Profile Width m/yr Coco Point Hotel Gravenor Bay Palm Beach Dulcina Hotel Palmetto Hotel Two Foot Bay Mean There was considerable variation in profile area and width, depending on several factors including location on the island and level of development on the beach. The effects of Hurricane Luis (1995) may also be a contributory factor. Up until 1995, erosion was the dominant process on most of the beaches of Antigua and Barbuda. The post-luis period shows a shift in that accretion became more prominent. This is normal, following a hurricane where sand removed to offshore are being redeposited on the beach. Most beaches have still not recovered fully from this hurricane. 4

9 MONITORED BEACHES IN ANTIGUA Dickenson Bay Jabberwock Beach N Fort James Beach Runaway Bay Dutchman Bay Figure 1. Deep Bay St. John's Monitored Beaches in Antigua Stony Horn Beach Yorks Beach Mosquito Cove Long Bay Lignumvitae Bay Ffryes Beach Darkwood Beach Crab Hill Bay Falmouth Beach Halfmoon Bay Morris Bay Pigeon Point Beach Mamora Bay LEGEND Beach. Road Kilometers Fisheries Division, Antigua

10 Monitored Beaches In Barbuda N Two Foot Bay Low Bay (Palm Beach) CODRINGTON Palmetto Hotel Dulcina Hotel Cocoa Point Hotel Gravenor Bay LEGEND Beach Road Kilometers Contour Fisheries Division, Antigua 2003 Figure 2 Monitored Beaches in Barbuda 6

11 Coastal development, particularly in Antigua, continues to significantly determine the structure and configuration of the coastline. Based on past experiences, attempts have been made to maintain important coastal ecosystems, including coral reefs, sea grass beds, beaches and wetlands. Coastal development setbacks have been designed for Antigua and Barbuda but their implementation is relatively slow. A draft policy framework for the management of beaches has also been developed. In addition, critical recommendations have been made for the management of sand as a national, natural resource. Table 2. Antigua: Beach Changes BEACH Change in Profile Area m 2 Change in Profile Width m/yr Jabberwock Beach Dutchman Bay Long Bay Half moon Bay Mamora Bay Pigeon Point Beach Falmouth Beach Morris Bay Crab Hill Bay Darkwood Beach Ffryes Bay Lignumvitae Bay Mosquito Cove Yorks Beach Stony Horn Beach Deep Bay Fort James Beach Runaway Bay Dickenson Bay Mean Although the beach-monitoring programme provides the mean conditions for the beaches around Antigua and Barbuda, the system can be improved if a wider variety of beaches are monitored with even greater precision and regularity. This will include the geo-referencing of the beachmonitoring sites, additional training in beach monitoring activities and the analysis of beach data, all of which will necessitate an increase of the resources of the Fisheries Division (FD). The capability of the Fisheries Office in Barbuda would need to be improved. 7

12 INTRODUCTION A project, Managing Beach Resources and Planning for Coastline Change, Caribbean Islands which started in the mid 1980s, has concentrated on developing capacity in the small islands of the Caribbean to effectively manage beach resources. Starting initially with beach erosion, the project established monitoring programmes within government agencies, NGOs and sometimes schools, so that stakeholders could understand the changes taking place on their beaches and begin to develop solutions to those problems. The challenge now facing the project is to develop ways to convince senior decision-makers of the need, indeed the necessity, to implement some hard decisions, such as controlling beach sand mining and beachfront development. The project was formerly titled Coast and Beach Stability in Lesser Antilles of the Caribbean and is known locally by an old acronym COSALC. The goal of the project was to develop in-country capabilities so that small islands of the Caribbean, particularly the Organization of Eastern Caribbean States (OECS), often economically dependent on coastal tourism, can effectively manage their changing beach resources and plan for coastline change in a framework of integrated coastal management. The initial focus was on small islands in the eastern Caribbean but recently the scope has widened to include Haiti and the San Andres Archipelago (Colombia). Dr. Gillian Cambers, g_cambers@hotmail.com, was the main coordinator of the programme. The beach-monitoring programme started in Antigua (1991) under COSALC, part of a UNESCO Coastal Marine Project replaced in 1995 by the new UNESCO programme: Environment and Development in Coastal regions and Small Islands (CSI) administered jointly by UNESCO and the University of Puerto Rico Sea Grant College Programme (UPR SGCP). The beachmonitoring programme eventually became the full responsibility of the Fisheries Division (FD) within the Ministry of Agriculture, Lands, Fisheries of Antigua and Barbuda. The staff of the FD, of Antigua and Barbuda, conducts Field monitoring and data analysis. 1 In the earlier part of the reporting period, technical support to the programme came mainly from UPR SGCP. Project funding was provided through USAID and the CDB. Volume 1 of this report summarizes the data collected over the period and follows three earlier reports published in 1993, 1994 and Volume 2 contains the detailed data for each of the 25 monitored beaches (19 beaches in Antigua and 6 beaches on Barbuda). These reports will provide useful information for other projects particularly related to global climate change and sea level rise. For example, it can be utilized in the Coastal Resource Inventory System (CRIS), a database created under the CPACC project. 1 The beach-monitoring activity used to be a joint activity of the Fisheries Division and the Development Control Authority (DCA). However, due to staff changes and difficulties with coordination, the involvement of the DCA ceased,

13 Antigua has a substantial database with continuous coverage over the period , which includes the effects of several hurricanes and tropical storms. Barbuda s database covers the period The information can be used in coastal planning and coastal erosion mitigation. BACKGROUND In recognition of the importance of coastal habitats, including coral reefs, sea grass beds, beaches and wetlands, to Antigua and Barbuda, the beach-monitoring programme provides critical information, which can be used in the promotion and development of wise practices within the coastal areas of Antigua and Barbuda. Figure 3. gives a simple diagram showing the various parts of a beach. A beach can be defined as a zone of loose material extending from the low water mark to a point landward where either the topography abruptly changes or permanent vegetation first appears. Although beaches are often made up of sand particles, they may also consist of clay, silt, gravel, cobbles or boulders, or any combination of these. The particle sizes of these sediments are shown in Table 3. The monitored beaches in Antigua and Barbuda are all sandy beaches. Figure 3. Cross-section of a Typical Beach After Cambers, 1996a An analysis of the influence of tropical weather systems on the coastal landscape of Antigua and Barbuda helps to provide a greater understanding of coastal processes during specific periods. Table 3. Sediment Sizes Clay Less than mm Less than inches Silt mm inches Sand mm inches Gravel mm inches Cobbles mm 3 10 inches Boulders Greater than 256 mm Greater than 10 inches 9

14 The methodology employed during each monitoring period may be improved over time, eventually increasing the accuracy and efficiency of the process. In addition, past records and reports can indicate trends that assist in predictions for the future. Tropical Weather Systems affecting Antigua and Barbuda Tropical weather systems are common in the northern and eastern Caribbean, including Antigua and Barbuda, between the months of June November, annually. Whether depression, storm or hurricane, these can affect wave motion around Antigua and Barbuda, even when they pass miles from land. Between 1996 and 2001, twenty (20) tropical weather systems have affected Antigua and Barbuda. These are indicated in Figure 4. and also listed in Appendix 1. Except for 2001, at least one (1) hurricane occurred per year between 1995 and The years 1996 and 1999 were particularly active in terms of tropical weather system activity, each with one (1) tropical storm and three (3) hurricanes. Once there is a tropical weather system affecting the area, depending on the location and magnitude of the system, one or more of the following are likely to occur: Increased erosion along beach segments, leading to narrowing of the beach (profile width decrease), less sand available (profile area decline) and the eventual loss of sand (consequently, beachrock will become exposed) Increased accretion along beach segments, translated to possible increases in profile area and width (actual piling up of sand along areas of the coast) Change in the position of the dune base. Figure 4. No. Tropical Weather Systems affecting Antigua and Barbuda Tropical Depression Tropical Storm Hurricane The effects of tropical weather systems can be either positive, negative or both, on the same beach depending on existing conditions of the beach and the relative characteristics of the system. There may also be monthly or annual variations in weather conditions and consequently the shoreline environment will change. 10

15 Following a tropical weather system, particularly a hurricane, beaches usually become lower and narrower. Thus, waves may be able to reach roads or buildings that were away from the active wave impact zone before the hurricane. Some beaches may be totally stripped of their sand leaving rock outcrops exposed. Rocky ledges often consisting of beachrock may become exposed where they were not evident before. Considerable quantities of beach sand have been moved inland and deposited on coastal roadways, in swimming pools and on beachfront properties. Large volumes of sand may also be moved offshore. The water depth in the offshore zone may be much shallower than before the hurricane. Sand dunes, which were previously gently sloping and covered with vegetation, will now stand at a near-vertical angle and bare of vegetation. (See Figure 5.). In small sandy bays, sometimes all the sand will have been transported to one end of the beach. The material composing the beach may have changed from sand to stones and boulders. Figure 5. Dune retreat after a hurricane. The dune face has been eroded leaving a near vertical slope. In the months following the hurricane, the sand will slump to form a more stable slope (adapted from Cambers, 1995). Past Activities Re: Beach Monitoring in Antigua and Barbuda Previous reports for the beach monitoring programme (Black et al 1994, 1995, 1996) showed that there were considerable variations in the data from site to site and from year to year. The data have shown that between 1992 and 1995, 9 of the 25 monitored beaches in Antigua and 11

16 Barbuda 2 were showing erosion as the dominant coastal process. Erosion was more severe during times of tropical weather systems. Following the passage of Hurricane Georges (1998), an analysis was done of beach erosion as a hazard in Antigua and Barbuda 3. This study has shown that monitored beaches fell within the categories given in Table 4. Most of the monitored beaches on Antigua (17) fell within the medium to high hazard category with two being low (Crab Hill Bay and Lignumvitae Bay). The hazard categories for Barbuda ranged from the extreme of very low (Dulcina) to very high (Palmetto Point). Both technical and non-technical reports are available on the OAS website which provides more details. 4 Table 4. Beach Erosion Hazard Hazard category Rate of Coastal Change (m/yr) Monitored Beach Very low to Dulcina Hotel Low to Two Foot Bay, Crab Hill Bay, Lignumvitae Bay Medium to Gravenor Bay, Cocoa Point Hotel, Pigeon Point Beach, Mamora Bay, Falmouth Beach, Stony Horn Beach, Yorks Beach, Jabberwock Beach, Dutchman Bay, Halfmoon Bay, Darkwood Beach, Ffryes Beach, Runaway Bay High 0.44 to Morris Bay, Fort James Beach, Dickenson Bay, Low Bay, Long Bay, Deep Bay, Mosquito Cove. Very high 2.35 to Palmetto Hotel As part of the CPACC Project, Antigua and Barbuda s involvement included the development of economic instruments for enhancing coastal management. The focus was on sand management with a view of meeting demands for sand without undermining the environmental integrity of coastal ecosystems. The programme therefore sought to manage sand as a national, natural resource, in a sustainable way. 2 Beaches on Barbuda were not assessed prior to OAS Post Georges Disaster Mitigation Project

17 In addition there are other beach related projects administered by different government agencies. These include the management of sand, for construction purposes, by the Ministry of Communications and Works (MCW) or Public Works and various beach cleaning and beautification activities by the Ministry of Tourism and the Environment (MTE). These projects need to be integrated into a wider coastal development plan for Antigua and Barbuda. METHODOLOGY The FD continues to employ the same methodology developed in There are however, slight improvements in the instruments used and the computer programme utilized in data analysis. Twenty-five (25) beaches were monitored between 1996 and These included: Dickenson Bay (4 Sites) Runaway Bay (3 Sites) Fort James Beach (2 Sites) Deep Bay (2 Sites) Stony Horn Beach (2 Sites) Yorks Beach (2 Sites) Mosquito Cove (1 Site) Lignumvitae Bay (3 Sites) Ffryes Beach (3 Sites) Darkwood Beach (3 Sites) Crab Hill Bay (1 Site) Morris Bay (1 Site) Falmouth Beach (1 Site) Pigeon Point Beach (2 Sites) Halfmoon Bay (3 Sites) Long Bay (2 Sites) Mamora Bay (1 Site) Dutchman Bay (3 Sites) Jabberwock Beach (2 Sites) Gravenor Bay (1 Site) Cocoa Point Beach (3 Sites) Dulcina Hotel (1 Site) Palmetto Hotel (1 Site) Low Bay (1 Site) Two Foot Bay (1 Site) Measurements for beach monitoring continue every three (3) months. This provides a profile across the beach, starting from an established reference point at the back of the beach and ending in the water at the first offshore step, which usually coincides, with the wave breakpoint. The upgraded software used in the analysis automatically generates the cross sectional area under the beach profile, adjusted to a standard vertical drop below the reference point, as well as the width of the profile. This fully-compiled software programme, entitled Beach Profile Analysis, provides basic information for data analysis and the graphical representation of beach change trends, specifically the following: 13

18 Entry of beach profile data collected in the field; Computation of beach profile area and width; Graphical plots of beach profiles; Composite plots showing several profiles on the same graph; Preparation of data tables for individual sites showing values for profile cross sectional area and profile width as well as annual means; Preparation of trend graphs showing changes in profile area and width over time. The programme has four main routines: data entry, graphical plots of the beach profiles, data tables, and trend graphs. The profiles and graphs can be easily transferred to word processing documents. Changes in profile area are calculated in square metres (m 2 ). First, using the quarterly values generated, the mean profile area is calculated for the base year. Then the mean for the subsequent years is calculated and averaged. The two means are then compared and the change determined. The change in profile area may be expressed as either positive or negative. A positive figure is an indication that the profile is increasing and accretion is the dominant process while a negative figure indicates a decrease in profile area or erosion. Profile width is measured in metres (m). Changes in profile width are determined in a similar manner to changes in profile area. Following the calculation of the mean profile width for the baseline year and the mean width for subsequent years, the difference between the two mean figures is determined and divided by the number of years to give the change in profile width. This change is expressed in metres per year (m/yr). A positive change indicates accretion while a negative change shows that the profile has narrowed or eroded. This report provides information on changes in Antigua ( ) and Barbuda ( ). General trends are given relative to the passage of tropical weather systems and where data is available, comparisons are made with beach changes prior to

19 RESULTS: Beach Changes at Individual Beaches This section gives a general description of the quantitative and qualitative changes at each of the monitored beaches in Antigua and Barbuda. Antigua Sites Dickenson Bay: There are four sites at this beach. Between 1996 and 2001, the beach at Dickenson Bay was showing erosion. The mean profile area decreased by 1.10 m 2 and the profile width receded at a rate of m/yr. This beach continues to be one of the main beaches for tourism development in Antigua and Barbuda. Runaway Bay: There are three (3) measurement sites at this beach. Between 1996 and 2001, this beach was showing accretion, the mean profile area increased by 4.10 m 2 while the mean profile width increased at a rate of 0.46 m/yr. Following Hurricane Luis in 1995, beach recovery continues along segments of the beach. However, there was some slight erosion on the northern end of the beach following serious erosion the previous period. Fort James Beach: There are two (2) measurement sites at this beach. Between 1996 and 2001, this beach was showing erosion, the mean profile area decreased by m 2 while the width decreased at the rate of -0.21m/yr. Deep Bay: This beach is relatively protected but the two (2) measurement sites were showing erosion. Between 1996 and 2001, the whole beach is showing decreases in mean profile area (-6.01 m 2 ) and width (-0.73 m/yr). Yorks Beach: There are two (2) measurement sites at this beach. Between 1996 and 2001, this beach was showing accretion, both the mean profile area and width increased drastically (17.6 m 2 and 0.90 m/yr, respectively). This represents major recovery following periods of sand mining combined with the effects of Hurricane Luis. There were small amounts of erosion on the northern end of the beach during the reporting period. 15

20 Stony Horn Beach: There are two (2) measurement sites at this beach. This beach was showing accretion. Between 1996 and 2001, the mean profile area and width increased by 4.12 m 2 and a rate of 0.52 m/yr, respectively. This beach has not yet recovered to its pre-1995 levels. Mosquito Cove: One site is measured at Mosquito Cove. Over the years, dredging of the channel into Jolly Harbour and sand mining have affected the coastal processes. Erosion is the dominant process along this beach. Between 1996 and 2001, the mean profile area and width decreased by 4.12 m 2 and at a rate of m/yr, respectively. Crab Hill Bay: One site is measured on the beach at Crab Hill Bay. Between 1996 and 2001, extensive construction of buildings occurred on this beach. Accretion is the dominant process, the mean profile area and width increased by m 2 and at a rate of 0.34 m/yr, respectively. Deposits of sand are necessary for compensation for lost sand on the beach during times of grounds swells, when erosion is the dominant coastal process. Morris Bay: Morris Bay has one (1) measured beach-monitoring site. Accretion is the dominant process along this beach for the period The mean profile area and width increased by 2.98 m 2 and at a rate of 0.37 m/yr, respectively. Even with this rate of accretion, this beach has not yet recovered to its pre-1995 levels. Lignumvitae Bay: Three (3) sites are measured at Lignumvitae Bay. Between 1996 and 2001, accretion is the dominant process along this beach. The mean profile area and width increased by 5.24 m 2 and at a rate of 0.23 m/yr, respectively. This may be due to the effects of the groynes built along that beach. Ffryes Bay Ffryes Bay has three (3) sites that are measured. For the period , the whole beach experienced reductions in mean profile area (-9.77 m 2 ) and width (-0.53 m/yr) indicating that erosion is the dominant process. Darkwood Beach There are three sites measured at Darkwood Beach. Between 1996 and 2001, the beach experienced erosion at both ends but the mean profile area (2.26 m 2 ) and width (0.42 m/yr) 16

21 indicate that accretion is the dominant process. This varies between the different ends of the beach. Marmora Bay For the period , erosion has been the dominant process along Mamora Bay. The mean profile area and width were m 2 and m/yr, respectively. Falmouth Beach Accretion is the dominant process on Falmouth Beach between 1996 and The mean profile area was 0.96 m 2 while the profile width was decreasing at a rate of m/yr. This beach is narrowing slowly. Pigeon Point Beach Two (2) sites are measured at Pigeon Point Beach. Between 1996 and 2001, erosion was the dominant process with the beach experiencing erosion at both ends with mean profile area and width of m 2 and m/yr, respectively. Half Moon Bay There are three (3) sites that are measured at Half Moon Bay. Between 1996 and 2001, accretion was the dominant process along this beach. The mean profile area and width increased by 5.67 m 2 and at a rate of 0.31 m/yr, respectively. Segments of this beach, continue to experience periodic erosion. Long Bay Long Bay has two (2) beach monitoring sites. Between 1996 and 2001, erosion was the dominant process at this beach. The mean profile area and width decreased by 0.48 m 2 and at a rate of m/yr, respectively. Dutchman Bay Three (3) sites are measured at Dutchman Bay. For the period , erosion was the dominant process along this beach. The mean profile area decreased by 0.57 m 2 and the width was reducing at a rate of m/yr. Jabberwock Beach There are two (2) sites that are measured at Jabberwock Beach. Erosion is the dominant process along this beach. During , the mean profile area was m 2 while the profile width decreased at a rate of 0.11m/yr. 17

22 Barbuda Sites Cocoa Point Beach Three (3) sites are measured at Cocoa Point Beach. Between 1996 and 2000, accretion was the dominant process along this beach. Even though the southern point was eroding, the mean profile area and width were 0.23 m 2 and 0.73 m/yr, respectively. Gravenor Bay (Spanish Point) Between 1996 and 2000, accretion was the dominant process along Gravenor Bay. For that period, the mean profile area and width were 0.67 m 2 and 1.01 m/yr, respectively. Dulcina Hotel Accretion was the dominant process along Dulcina Hotel, between 1996 and For that period, the mean profile area and width were 0.18 m 2 and 1.32 m/yr, respectively. Palmetto Hotel Accretion was the dominant process along Palmetto Hotel. For the period , the mean profile area and width were 1.6 m 2 and 5.97m/yr, respectively. Shifting dunes characterize this beach. Low Bay (Palm Beach) Between 1996 and 2000, erosion was the dominant process at Low Bay with mean profile area and width of m 2 and m/yr, respectively. Two-Foot Bay For the period , accretion was the main process at Two-Foot Bay. The mean profile area and width during the period were 0.26 m 2 and 2.40 m/yr, respectively. Overall Beach Changes, The average beach changes between 1996 and 2001 are shown in Tables 5 and 6. The data is also shown graphically in Figures 6, 7 and 8. For the period , eleven (11) of the monitored beaches on Antigua were showing erosion at an average rate of 0.40 m/yr. These beaches were: Dickenson Bay m/yr Dutchman Bay m/yr Jabberwock Beach m/yr Long Bay m/yr Deep Bay m/yr Fort James Beach m/yr Pigeon Point Beach m/yr Ffryes Bay m/yr Mamora Bay m/yr Falmouth Beach m/yr Mosquito Cove m/yr 18

23 Eight (8) of the monitored beaches on Antigua were showing accretion at an average rate of 0.49 m/yr. These beaches were: Halfmoon Bay Darkwood Beach Stony Horn Beach Yorks Beach 0.31 m/yr 0.42 m/yr 0.52 m/yr 0.90 m/yr Morris Bay Crab Hill Bay Lignumvitae Bay Runaway Bay 0.37 m/yr 0.34 m/yr 0.23 m/yr 0.46 m/yr For the period , on Barbuda, one (1) monitored beach was showing erosion, Palm Beach (-0.80 m/yr). For the same period, the other five (5) monitored beaches were showing accretion at an average rate of 2.40 m/yr. These were: Gravenor Bay 1.01 m/yr Dulcina Hotel 1.32 m/yr Palmetto Hotel 5.97 m/yr Two Foot Bay 2.40 m/yr Cocoa Point Hotel 1.30 m/yr Table 5. Barbuda: Individual Beach Changes Beach Change in Profile Area m 2 Change in Profile Width m/yr Gravenor Bay Palm Beach Dulcina Palmetto Two Foot Bay Coco Point Site A Site B Site D Mean Beac h Scene : Fort James 19

24 Table 6. Antigua: Individual Beach Changes Beach Dickenson Bay Change in Profile Area m 2 Change in Profile Width m/yr Site A Site B Site C Site D Site E Mean Dutchman Bay Site A Site B Site C Mean Half moon Bay Site A Site B Site C Mean Runaway Bay Site A Site B Site C Mean Darkwood Beach Site A Site B Site C Mean Ffryes Bay Site A Site C Site D Mean Lignumvitae Bay Site A Site B Site D Mean Jabberwock Beach Site A Site B Mean Long Bay Site A Site B Mean Deep Bay Site A Site B Mean Fort James Beach Site A Site B Mean Pigeon Point Beach Site A Site B Mean Stony Horn Beach Site A Site B Mean Yorks Beach Site A Site B Mean Mamora Bay Falmouth Beach Morris Bay Crab Hill Bay Mosquito Cove

25 Figure 6. Antigua: Changes in Profile Area, Changes in Profile Area ANTIGUA Area (m 2 ) Dickenson Bay Runaway Bay Fort James Deep Bay Stony Horn Yorks Mosquito Cove Lignumvitae Bay BEACH Ffryes Darkwood Crab Hill Bay Morris Bay Falmouth Pigeon Point Mamora Bay Halfmoon Bay Long Bay Dutchman Bay Jabberwock 21

26 Figure 7. Antigua: Changes in Profile Width, Changes in Profile Width ANTIGUA Dickenson Bay Runaway Bay Fort James Deep Bay Stony Horn Yorks Mosquito Cove Lignumvitae Bay Ffryes Beach Darkwood Crab Hill Bay Erosion / Accretion Rates (m/yr) Morris Bay Falmouth Pigeon Point Mamora Bay Halfmoon Bay Long Bay Dutchman Bay Jabberwock Beach Under Attack: Valley Church 22

27 Figure 8. Barbuda: Changes in Profile Area, Changes in Profile Area BARBUDA Two Foot Bay Palmetto Beach Dulcina Palm Beach Gravenor Bay Coco Point Area (m 2 ) 23

28 DISCUSSIONS From the beach monitoring data collected, certain general conclusions may be formulated. Based on the methods of validation for the data, during and after input, it is assumed that errors in the data are minimal. The calculated means therefore give the average conditions existing on a particular beach. Under normal conditions, longshore currents produce longshore drift along the foreshore. This produces seasonal variations on the different segments of the beach. One side of the beach may experience erosion while there is accretion on the opposite end i.e. seasonal erosion and deposition. This effect depends on the location of the beach, leeward or windward coast, its topography and the characteristics of the prevailing winds (the Northeast Trade Winds ). It is difficult to determine the effects of tides and tidal currents on the processes operating on the beach. Most of the monitored beaches in Barbuda expanded in profile width during the period The average rate of increase for the entire island was 0.27 m/yr. However, all the Palmetto Hotel Sand Mining Dickenson Bay monitored beaches that were accreting fell within a range of 1.01 to 5.97 m/yr, i.e., well above the average for the monitored beaches on the island. Specific sections of these beaches have periodically experienced erosion, especially during periods when Barbuda came under the influence of some tropical weather system. The beach along Palmetto Point experienced considerable variations in profile width throughout the year. This may account for the high accretion rates. The Palmetto Hotel is always in danger as it was built close to the coastline. Even though Two Foot Bay is exposed to the Trade Winds (on the windward side), it still experienced a high rate of accretion. Offshore coral reefs provide temporary shelter. It is significant that Low Bay (Palm Beach) is the only monitored beach in Barbuda that experienced an overall decrease during the reporting period. This beach borders the narrow strip of land, enclosing the Codrington Lagoon. The fact that Palm Beach is eroding may have implications for the proposed development of the area. On a whole, the monitored beaches in Antigua experienced a slight rate of decrease of m/yr. However, the monitored beaches that were eroding fell within a range of 0.07 to 1.39 m/yr, i.e., all more severe than the average for all monitored beaches on the island. It is difficult 24

29 Boon Bay Marina Bay Emerald Cove to determine the exact cause (s) of the general trends. The following may have some impact, whether individually or combined: Construction of structures close to the shoreline (buildings, seawalls, groynes, revetments, etc,) Sand mining on or near to a beach Deposition of material, including beach nourishment (sediments/deposits include boulders, sand, marl, etc,) Removal of beach materials, and vegetation from close to the beach Dredging and the digging of trenches on the beach Marina development. Natural forces, including hurricanes, tropical storms and depressions, storm surge, groundswells, sea level rise. There are wide variations in the characteristics of beaches where erosion dominate. These cannot be distinguished based on the degree of shelter of beaches, beach location, orientation and use. Rocky Coastline Sandy Beach Although The Fisheries Division (FD) is the main partner agency responsible for beach data collection and analysis 5, the updated beach change database and software Beach Profile Analysis were installed at the FD, DCA within the CDB-UNESCO project. For the DCA, the 5 The Fisheries Division are also developing the capacity for wetlands, sea grass and coral reef monitoring 25

30 benefits of monitoring go beyond data collection, and include observation and assessment of new structural developments, changing beach uses, restriction of beach access, nature of beach dynamics, etc. The officers of DCA, particularly those who are directly involved in the monitoring of development activities, should become knowledgeable about all aspects of their island s beaches and can thus play an active role in beach management and the enforcement of regulations. As in other islands, one of the major problems encountered in beach-monitoring is the loss of profile reference points during hurricanes, even when they are located a considerable distance inland from the vegetation line. When this happens, new reference points have to be located, which obviously interrupts the data trend for that particular site. One solution to this problem involves fixing the position of the beach profile reference points with a global positioning system (GPS). Lost reference points can be located spatially after a hurricane with a fair degree of accuracy, however, changes in the height of the point will not be reflected. The proliferation of hard structures, particularly vertical sea walls, on the beaches in Antigua is another serious problem. However, this will need a concerted effort involving several agencies. Even in Barbuda, which has a low level of beachfront development, there are examples of serious erosion and loss of buildings (August/September 2000). The implementation of the building setback guidelines, developed in 1998, would assist in reducing the problems caused by developments positioned too close to the active beach zone. Beach sand mining continues to be a problem in Antigua. Existing environmental laws related to sand mining needs to be strengthened and implemented. 26

31 RECOMMENDATIONS One of the problems present in Antigua and Barbuda is the sectoral nature of government and the difficulties this poses for fields such as integrated coastal management. There has been much talk about the sharing of information (findings, conclusions, applications) but the difficulties involved in actually sharing data are yet to be fully resolved. Issues such as data ownership and the value of data need further discussion. The beach-monitoring programme can be further improved with the geo-referencing of the reference points for individual beach sites. This would make the reference points more permanent. The computer software would also need to be modified to accommodate GPS readings. This could be achieved through the incorporation of the data into a geographical information system (GIS). The following recommendations can help in the preservation and sustainable use of beach and other coastal space: Expansion of the beach-monitoring programme to include more beaches including nonsandy beaches. In the long run, more characteristics of beaches may be measured. This can improve the aspect of representativeness of beaches in Antigua and Barbuda. Development and implementation of a comprehensive integrated Coastal Development Framework for Antigua and Barbuda; this should incorporate development both on land as well as in the nearshore coastal waters. This requires the coordination of several government agencies. Implementation of the established Coastal Development Setback Guidelines for Antigua and Barbuda Development of a policy for the management of sand as a national, natural resource, including the development of suitable alternatives to the use of beach sand as a construction material In the long term, to educate schoolchildren, their parents and communities in the scientific monitoring and wise management of their beach resources; they should also be involved in the monitoring activities. Continuation of beach-monitoring activities and ensuring that the reports are shared with all stakeholders. A policy of sharing costs of these activities may be necessary. Development of linkages and the sharing of experiences with agencies responsible for beach-monitoring within the Caribbean and other similar regions of the world. 27

32 REFERENCES Black et al, 1996 a. Black et al, 1996 b. Analysis of Beach Changes in Antigua and Barbuda between 1992 and 1995, Volume 1 Assessment Report, COSALC report, 36 pages. Analysis of Beach Changes in Antigua and Barbuda between 1992 and 1995, Volume 2 Data Report, COSALC report, 93 pages. Cambers, G Year of the hurricanes. Sea Grant in the Caribbean, Puerto Rico, October December 1995, pp Cambers, G a. Hurricane Impacts on Beaches in the Eastern Caribbean Islands, UNESCO UPR SGCP, 96 pages. Cambers, G b. CSI 1: Managing Beach Resources in the Smaller Caribbean Islands: Workshop papers, UNESCO UPR SGCP, 270 pages. Cambers, G Cambers, G Planning for Coastline Change: Guidelines for Construction of Setbacks the Eastern Caribbean Islands, CSI info 4 UNESCO, Paris, 14 pages Planning for Coastline Change 1: Coastal Development Guidelines in Antigua and Barbuda. COSALC Report, UNESCO UPR SGCP, 63 pages Cambers, G Wise Practices for Coping with Beach Erosion, UNESCO Publications, 9 pages. James, P a. James, P b.. Perch, L. (2001) Coastal erosion hazard mapping for Antigua and Barbuda: Technical summary. OAS/USAID Post-Georges Disaster Mitigation Project, 31 pp. Coastal erosion hazard mapping for Antigua and Barbuda. Non-technical summary. OAS/USAID Post-Georges Disaster Mitigation Project, 11 pp. Beach Management: An Integrated Adaptive Approach. CPACC Publications, 25 pages

33 APPENDIX. Appendix 1. Major Tropical Systems Impacting Antigua and Barbuda YEAR TROPICAL SYSTEM Name Type Effective Date Location Chantal TD Jul. 13 North Iris TS Aug. 27 East Marilyn H Sep. 14 West Sebastian TD Oct. 23 North Luis H Nov. 5 Landfall Bertha H Jul. 7 North Edouard H Aug. 31 X North Fran TS Sep. 8 South Isadore H Sep. 28 X North Erika H Sep. 6 North Grace TS Oct. 15 X North Bonnie TS Aug. 20 North Dannielle H Aug. 27 X North Georges H Sep. 20 Landfall Emily TS Aug. 26 X East Floyd H Sep. 11 X North Jose H Oct. 20 Landfall Lenny H Nov. 19 Landfall Chris TD Aug. 19 East Debby H Aug. 21 South Helene TD Sep. 16 South Chantal TD Aug. 16 X South Erin TS Sep. 5 X East Iris TD Oct. 4 X South Jerry TS Oct. 8 X South H hurricane TS Tropical Storm TD Tropical Depression X Extra 29