Drought Hazard Assessment and Mapping for Antigua and Barbuda · Drought Hazard Assessment and Mapping for Antigua and Barbuda Post-Georges Disaster Mitigation Project in Antigua

Drought Hazard Assessment and Mappingfor Antigua and Barbuda

Post-Georges Disaster Mitigation Projectin Antigua & Barbuda and St. Kitts & Nevis

April 2001

This report was prepared under contract with the OAS by Ivor Jackson, Ivor Jackson &Associates, Environmental & Landuse Planning and Landscape Architecture, P.O. Box 1327, St.John’s, Antigua. Tel/fax: 268 460 1469. E-mail [email protected].

CONTENTS

1.0 BACKGROUND 4

1.1 Introduction 51.2 Terms of Reference 51.3 Methodology 51.3.1 Data Collection 51.3.2 Mapping 51.4 Definitions 51.4.1 Drought 51.4.2 Drought Hazard 71.4.3 Drought Vulnerability 71.4.4 Drought Risk 71.4.5 Use of the Term Drought 7

2.0 ASSESSMENT 8

2.1 Meteorological Conditions 9

2.1.1 Precipitation 92.1.2 Temperature 102.1.3 Winds 102.1.4 Relative Exposure of Slopes 112.1.5 Relative Humidity 122.1.6 Sunshine and Cloud Cover 122.1.7 Evaporation and

Transpiration 12

2.2 General EnvironmentalConditions 13

2.2.1 Geology 132.2.2 Slopes 132.2.3 Soils 132.2.4 Vegetation 152.2.5 Soil Water Deficiencies 162.2.6 Water Resources 17

2.3 Land Use and Land ManagementPractices 18

2.3.1 Crop and Vegetable Farming 182.3.1.1 Major Farming Areas 182.3.1.2 Type of Crops 18

2.3.1.3 Farming Practices 20

2.3.2 Livestock Farming 202.3.2.1 Livestock Population 202.3.2.2 Livestock Distribution 212.3.2.3 Livestock Management

Practices 222.3.2.4 Market and Prices 22

2.3.3 Settlements andCommunities 22

2.3.4 Hotels and Tourist Zones 24

2.4 Infrastructure 25

2.4.1 Dams and other StorageReservoirs 25

2.4.2 Wells 262.4.3 Desalt and other Water

Treatment Plants 272.4.4 Wastewater Treatment

Plants 282.4.5 Irrigation Systems 282.4.6 Water Distribution 292.4.7 Roof Catchments and Storage

Cisterns 292.5 Water Supply and Demand 29

3.0 IMPACT ANDVULNERABILITY 31

3.1 Historic Drought 323.1.1 Description of Drought

Events 323.1.2 Drought Impacts 323.1.2.1 Environmental Impacts 323.1.2.2 Economic Impacts 34

a) Agriculture 34b) Tourism 36c) Settlements 37

Drought Hazard Assessment & Mapping for Antigua and Barbuda

1

CONTENTS (Continued)

3.2 Future Vulnerability 38

3.2.1 Agriculture 383.2.2 Tourism 393.2.3 Settlements 40

3.3 Institutional Arrangements 41

3.3.1 Key Agencies 413.3.2 Procedures and Information 41

4.0 ANALYSIS OF AREAS ATRISK 42

4.1 Understanding and Applying theConcept of Risk 43

4.2 Areas at Risk to Drought 434.2.1 Drought Risk Criteria for

Mapping 434.2.2 Area and Issues for Priority

Attention 47

5.0 DROUGHT MAPPING 50

5.1 Data Collection Sources 515.2 Structure and Content of

Maps 515.3 Analysis of Data 515.4 Map Use and Limitations 52

6.0 INDICATORS FOR FUTUREIDENTIFICATION OFDROUGHTS 54

References 58

Appendices 59

1 Terms of Reference 602 Average Yearly Rainfall,

Recorded at the MeteorologicalOffice, V.C. Bird InternationalAirport, 1960 – 2000 62

3 Antigua Annual Rainfall, 1950-1984 62

4 1991 Population Density,Antigua and Barbuda 63

5 Structure (Content) of MappedData Sets, Antigua andBarbuda 64

6(a) Drought Risk Totals byWatersheds, Antigua 65

6(b) Drought Risk Totals byWatersheds, Barbuda 66

7 Map References from Antigua and Barbuda Country environmental Profile, IRF, 1991 678 List of Contacts 68


2

List Of Tables

Table 1: Categories of Drought asDefined by % of Average YearlyRainfall of 40.98 Inches (Antigua) 6

Table 2: Rainfall, Windspeed andRelative Humidity, Driest and WettestMonths of the Year 10

Table 3: Water Balance at PotworksReservoir November1995 – May 1996 12

Table 4: Slope Classes, Barbuda 13

Table 5: Livestock Population inAntigua/Barbuda, 1984 20

Table 6: Cattle, Sheep and GoatPopulations Antigua, 2001 20

Table 7: Tourism Accommodation,Antigua and Barbuda, 2001 24

Table 8: Distribution of Hotel Propertiesby Watersheds 24

Table 9: Location and Capacity ofAgricultural Reservoirs, Antigua 25

Table 10: Municipal Reservoirs,Antigua 26

Table 11: Major Well Fields ofAntigua 26

Table 12: Water Storage and Well Yieldby Watersheds, Antigua 27

Table 13: Water Supply, Antigua andBarbuda 30

Table 14: Drought Years in Antigua/Barbuda 1960-2000 32

Table 15: Drought Risk Criteria 44

Table 16: Drought Risk Ranking ofAntigua Watersheds 51

Table 17: Drought Risk Ranking ofBarbuda Watersheds 52

Table 18: Drought Levels at WellFields, Antigua 56


3

_________________________________ 1.0 BACKGROUND


4

1.1 Introduction

The Organization of American States(OAS) as part of its Post-GeorgesDisaster Mitigation Project (PGDM)commissioned this drought hazardassessment and mapping study forAntigua/Barbuda.

One of the major objectives of thePGDM is the “development of nationalgoals, objectives and actions to reducethe vulnerability of Antigua/Barbuda …to the effects of natural hazards.”

1.2 Terms of Reference

The Terms of Reference (TOR) for thestudy is attached as Appendix 1. Thereare two major component products ofthis assignment, (i) a drought hazardassessment report and (ii) island wideGIS data layers depicting drought hazardrisk areas and drought hazard maps forAntigua/Barbuda.

1.3 Methodology

1.3.1 Data Collection

Data for map preparation and fordrought assessment were collected usingsecondary sources, reports, maps,personal communication and limitedfield observations.

1.3.2 Mapping

Maps were first manually prepared andthen digitized using GIS application, ArcView.

1.4 Definitions

For the purposes of the study and inagreement with relevant authorities, adefinition of drought has been drafted, asindicated below. Other relevantdefinitions are also provided to facilitateboth the drought hazard assessment andmapping work.

1.4.1 Drought

Drought is a recurrent feature ofAntigua/Barbuda’s climate. It occurswhen there is an extended period ofdeficiency in precipitation (relative towhat is considered normal), which isthen insufficient to meet economic,social and environmental demands.Given their relatively small size, droughteffects in Antigua and Barbuda are feltisland-wide.

For reasons of analysis and in view ofthe need to determine appropriateresponses to drought impacts andvulnerability, drought is defined ashaving three critical but inter-relatedcomponents (as taken from the USNational Drought Mitigation Center’sdefinition) namely:

• Meteorological drought• Agricultural drought• Hydrological drought

a) Meteorological drought

Meteorological drought is definedmainly by deficiencies in precipitation.Along with deficient rainfall, conditionsduring drought may be accompanied oraggravated by high temperatures, strongwinds, low relative humidity, greatersunshine and less cloud cover.


5

These conditions can be expected tobring increased evaporation andtranspiration, reduced water infiltrationinto soils and a reduction in deeppercolation and ground water recharge.

The Antigua/Barbuda MeteorologicalOffice (Met Office) has categorizeddrought from slight to extreme, asshown in Table 1.

Table 1 Categories of Drought, asDefined by % of Average YearlyRainfall of 40.98 inches (Antigua)

Category Rainfall % of Ave.Drought (inches) Annual Rainfall_______________________________

Slight 38.93 95Mild 36.88 90Moderate 32.78 85Moderate/Severe 30.74 80Severe 28.69 75Extreme 24.50 70_______________________________(Source: Meteorological Office, 2001)

Based on annual rainfall assigned toeach category by the MET Office, someform of drought occurred in Antigua in20 of the 40 years between 1960 and2000. Rainfall records for the periodwere collected by the Met Office (seeAppendix 2).

This does not match public recollectionand perception of drought. A moresimplified definition of meteorologicaldrought using the Met Office’sModerately Severe category, as the cut-off point would provide a definitionmore in keeping with public perception.

Meteorological drought forAntigua/Barbuda is defined using aprecipitation level of 80% or less ofyearly average rainfall (or < 30.74inches, Antigua and < 27.79 inches,Barbuda) for a drought year. Alimitation in using this definition is thatdrought designation is mostly done onthe basis of a calendar year and usuallyafter the event occurs.

For the purpose of droughtpreparedness, it is suggested thatprecipitation deficiencies over a six (6)month period could be used to predictan imminent drought.

For example, if the average monthlyrainfall for the dry period of the year,January to April, (2.06 inches forAntigua) is experienced over a six (6)month period, it would in publicperception signal that a drought wasimminent. At the end of a six (6) monthperiod in which total rainfall is < 12.36inches, effects associated withmeteorological drought would begin toemerge.

b) Agricultural drought

Agricultural drought occurs when plantwater demands cannot be met due tosoil water deficiency resulting fromdryness brought on by meteorological orhydrological drought.

In such cases plant water stress may beevidenced from reduced biomass andplant yield. One common indicatorspecies is the “evergreen” ficus, whichresponds by first dropping most or all itsleaves followed by the death of itsstems.


6

c) Hydrological drought

Conditions associated withmeteorological drought represent theearlier signs of drought followed byeffects of agricultural drought becauseplants are highly dependent on storedsoil water.

Hydrological drought can be considereda third stage in the evolution of droughtconditions evidenced by significantreduction in surface reservoirs, drying ofdams and wetlands. In this phase ofdrought, livestock may be severelyimpacted and other sectors begin to feelthe devastation.

1.4.2 Drought Hazard

A drought related hazard is an event inwhich a significant reduction of waterbrings about severe economic, social andenvironmental hardships to thepopulation of Antigua/Barbuda.

1.4.3 Drought Vulnerability

Vulnerability to drought is defined aseconomic, social and environmentalcharacteristics and practices of thecountry’s population that make itsusceptible to the effects of a drought.Vulnerability is reduced by the ability toeffectively plan for, anticipate, cope withand recover from droughts.

1.4.4 Drought Risk

The potential adverse effects ofdroughts viewed in relation to theirfrequency and severity combined withthe vulnerability of Antigua/Barbuda’spopulation determines the risk to suchevents.

1.4.5 Use of the Term Drought

In this report, reference is made to themeteorological, hydrological oragricultural drought as appropriate. Asimple working definition of droughtcould not be developed for thisassessment because of varyingperceptions of drought even for personsfamiliar with drought hazard assessmentliterature.

Broad-based discussions are neededbetween persons involved with droughtmitigation planning and those involvedwith sectors affected by drought in orderto build consensus and capacity tomanage drought.


7

_______________________________ 2.0 ASSESSMENT


8

2.1 Meteorological Conditions

2.1.1 Precipitation

Antigua

Average annual rainfall for Antigua is40.98 inches (Met Office, 2001).Rainfall records for Antigua 1950 –1984, as reported by the IslandResources Foundation (IRF), usingAPUA as its source, are summarized inAppendix 3. Records from 1960 – 2000based on observations at Coolidge by theMet Office are given in Appendix 2.

Both are presented because of variations,which suggest that the data was obtainedfrom two different stations. Attempts todetermine the position of the rainfallstation from which APUA records weretaken were unsuccessful. Both recordsshow significant variability inprecipitation between years from 1950 to2000.

A rainfall map, showing “long averageannual isohyetals” (IRF, 1991, after Hill,1966) indicates important variabilitybetween sections of Antigua, with thevolcanic hilly region in thesouth/southwest having up to 55inches/year, while coastal areas in thesoutheast, east and northeastexperiencing 35 inches/year.

Based on the average rainfall for coastalareas as cited by the isohyetals,precipitation >35inches/year (87.5% ofaverage annual rainfall) would notconstitute drought conditions, or elsesuch areas would be in a state ofconstant drought.

IRF identified two periods between 1950and 1990 as “periods of prolonged

drought” for Antigua. These are 1964 to1968, when the average rainfall was31.53 inches, and 1983 to 1984, whenthe average rainfall was 27.75 inches.

In the Met Office records, eight (8) yearsbetween 1960 and 2000 experiencedrainfall below 30.74 inches and couldtherefore be considered drought yearsfor Antigua.

Variation in monthly rainfall is anotherimportant consideration in droughtmanagement. The data show thatprecipitation is highest during themonths of August to December (wetseason) and lowest between January andApril (dry season).

Average wet season rainfall is 4.6 inches/month, while average dry seasonrainfall is 2.06 inches/month.

Therefore, for four months of the year(January to April) the average rainfall of2.06 inches is 60% of average monthlyrainfall for the 12 months of the year(3.41 inches) but the period is not longenough to be perceived by thepopulation as drought.

It is assumed however, that if dry seasonconditions were extended for six (6)months (12.36 inches of rainfall) thiswould, in public perception, constitutedrought conditions.

A critical constraint in the use of rainfalldata is the distribution of rainfallstations. Stations are lacking in the drierareas of the southeast, east and north ofAntigua, where shallow soils and therelative exposure to winds and marineinfluences tend to make such areasrelatively more susceptible to the effectsof drought.


9

In past years there were 70-95 raingauges located around Antigua (IRF,1991). Most are no longer in use.

Barbuda

The average annual rainfall for Barbudabetween 1965 and 2000 was 34.74inches (Met Office, 2001). During thisperiod, if < 27.79 inches/year of rain isused to define meteorological drought,then drought years were experienced in1966, 1967, 1968, 1971, 1977, 1983,1990, 1991, 1994 and 2000.

2.1.2 Temperature

Average temperatures are 29 degrees C(82.2 F) during the summer and 24degrees C (75.2F) during the wintermonths. Extreme highs of 34 degrees C(93.2F) in August and 15 degrees C(59F) in January have been recorded(IRF).

Despite their small size, both islandshave topographic and landscape features(including urban development), localizedwind patterns and soil characteristicsthat result in temperature variations overthe island. Such temperature differencesare not captured due to a shortage oftemperature recording stations.

Existing temperature stations recordsurface temperatures. Soil temperatures,which are critical to the performance ofsome plants and to agricultural crops, arenot normally recorded.

2.1.3 Winds

Easterly trade winds form a criticalcomponent of Antigua/Barbuda’sclimate. Yearly average wind speedsbetween 1969 and 1995 recorded at the

Coolidge Met Office, Antigua, was 12knots.

Highest average wind speed is recordedfor the month of July (14.2 knots).Critically, the lowest average windspeeds are for the months of September,October, November, which are the threewettest months of the year (see Table 2).

Table 2 also shows that the average windspeed for the driest months of the year is12.7 knots compared to the yearlyaverage of 12 knots. Average relativehumidity is significantly higher in thewet months.

Table 2: Rainfall, Windspeed andRelative Humidity, Driest and Wettestmonths of the Year

Rainfall Windspeed Relative (inches) (knots) Humidity

________________________________Dry months

January 2.34 12.8 81.0February 1.53 12.4 81.0March 1.77 12.1 81.0June 2.01 13.4 82.0

Ave. 1.91 12.7 81.25

Wet Months

September 5.29 10.8 84.0October 5.11 9.6 85.0November 5.14 10.5 85.0

Ave. 5.18 10.3 84.6_____________________________(Source: Met Office, 2001)Note: Average monthly rainfall data is based onrecords from 1960-2000. Average monthlywindspeed data is based on records from 1969 –1995 and average monthly relative humidity databased on records, 1960-1995.


10

Relatively speaking, winds are normallystronger in the dryer months when baresoils are exposed to its forces. Actualmonthly windspeed data were notobtained so as to determine if thisrelationship holds true for extended dryperiods (droughts).

It does suggest that wind speed is onefactor that makes soils more vulnerableto erosion during drought.

The records indicate that between 1991and 1995 the prevailing wind directionwas 090 degrees for eight months of theyear – shifting slightly to 100 degreesfor the months of April, June, andOctober and 110 degrees during themonth of May.

The drying effects of wind on soil isparticularly critical for exposed eastfacing slopes of the southeast, east andnortheast of Antigua and the Highlandson Barbuda’s east coast.

The stronger winds of the drier monthsrapidly remove moisture from soils,affecting in particular plants withshallow root systems.

The direct physical effects of the wind,combined with salt in the air contributeto the wilting of plants. Wilting alsooccurs from deficiencies in moisture.These localized effects have not beensufficiently studied although theirunderstanding is critical to theassessment of areas susceptible todrought.

Wind data for Barbuda was not obtainedbut it is assumed that average windspeeds do not vary significantly fromAntigua.

2.1.4 Relative Exposure of Slopes

The exposure of slopes to wind andsunlight affects vegetation and soils andrates of evaporation and transpiration.These influence localized climaticconditions, which may in turn affectconditions for grazing and growingcrops.

For example, light increasestranspiration (evaporation of moisturefrom leaf surfaces) rates more than itdoes evaporation rates (from waterbodies, soil). On the other hand windincreases evaporation rates more thantranspiration rates (OAS, 1991).

East facing slopes, particularly those atthe shoreline, therefore experiencerelatively higher evaporation andtranspiration rates than western facingslopes, where the afternoon sun has agreater effect on transpiration rates thandoes exposure to winds.

The critically exposed east facing slopesnear the coast in the Mamora/Isaac Hillregion of Antigua exemplifies the effectsof wind and light, along with the effectsof overgrazing by its barren landscape.

Western facing slopes in the highervolcanic region of Antigua enjoyrelatively better precipitation due toconvective influences. In this case,warmer air rising over the land surface atthe higher elevations cools andcondenses releasing its moisture onslopes west and northwest at theShekerley Mountains range.

Here, the area of influence is relativelysmall and the elevation not high enoughto cause the warming of descending air


11

and subsequent withholding of moisture.As a result, the arid conditionsexperienced on the lee of mountains inCentral America for example fromorographic precipitation do not exist.

2.1.5 Relative Humidity

Average relative humidity for dry andwet months was given in Table 2 basedon MET Office records. In addition, theIRF (1991) reporting from Loveless(1960) and Atkins (1983) claims that themean relative humidity for Antigua is inthe low 80’s in the morning and low 70’sin the evening.

Relative humidity is said to be higher inAntigua than in Barbuda and some of theother islands. Heavy dews deposited atnight on the island are believed tocontribute to water balance, particularlyin drier areas. The amount of watergained through this form of precipitationhas not been measured.

2.1.6 Sunshine and Cloud Cover

Antigua/Barbuda experiences ampleperiods of sunshine throughout thecourse of a year including the wetseason. The islands experience densecloud cover (as different from scatteredclouds) for much less than half of theyear.

Hence despite having average relativehumidity higher than neighboringislands, Antigua is normally dry andtemperatures relatively high. Because ofthe relationship of temperature to evapo-transpiration, rates for the latter areconsidered on par with other countries inthe Leeward Islands.

2.1.7 Evaporation and Transpiration

a) Evaporation

Evaporation rates for water bodies andsoils in Antigua/Barbuda are notgenerally available. Evaporation andseepage rates were calculated forPotworks Reservoir (between 152 and188 ha in reservoir area) duringNovember 1995 to May 1996.

The results, given in Table 3, show thattotal evaporation and seepage for theseven (7) month period (1.59 million cum) was over two times the amount ofwater supplied from the reservoir(691,091 cu. m). This is of criticalsignificance to water managementduring drought.

Although evaporation rates and volumeswere not separated, the results indicatethe relative quantities of water than canbe expected to be lost from surface waterbodies including municipal andagricultural storage reservoirs and dams.

Table 3 Water Balance at Potworks ReservoirNov 1995-May 1996Ave. Rainfall (monthly) 46.428mmTotal Rainfall (7 months) 325mmReservoir Area 173.7 haMonthly ave. reservoir vol. 3.4 mil. cu. mTotal reservoir vol. 23.8 mil cu. mMonthly rate evaporation/seepage 155mmMonthly ave. evaporation/seepage 227,628 cu mTotal evaporation/seepage 1.59 mil. cu. mMonthly ave. water supply 98,727 cu. mTotal water supply 691,091 cu. m(Source: Ministry of Trade & Planning,Government of Antigua)

Comparable estimates for other surfacewater bodies were not available and nosuch studies have been done to estimateevaporation from soils. However, it isassumed that evaporation rates increase


12

in areas where the soil has been exposedby overgrazing.

2.2 General EnvironmentalConditions

2.2.1 Geology

Antigua has a volcanic region (the hillysouthern portion of the island) and alimestone region at the northern part ofthe island. A central plain, referred to asthe third volcanic region, containsstratified volcanic detritus andagglomerates derived from theinfluences of the volcanic and limestoneregions. Barbuda is of limestoneformation.

Geology influences soil type andvegetation. In the case of Antigua andBarbuda, volcanic formation affects anddifferentiates topography. Geology istherefore an underlying factorcontributing to the assessment ofdrought impacts.

2.2.2 Slopes

Slopes in the volcanic region of Antiguaare mainly between 11 and 20 degrees(steeper in some cases), while in thelimestone and central plain region slopesare generally less than 10 degrees. InBarbuda, less than 1% of the slopes areover 10 degrees and these are found inthe Highlands (see Table 4). Slopeclasses are mapped on the droughthazard assessment slope data map forAntigua and on the slope data map forBarbuda.

Table 4 Slope Classes, Barbuda

Slope Class Area (acres) %(degrees)_____________________________

0-2 8,396 22.872-5 18,514 50.415-10 9,794 26.6710-20 20 0.05

Total 36,724 100.0_____________________________(Source: OAS, 1992)

2.2.3 Soils

Antigua

Hill et al did a detailed soil survey ofAntigua and Barbuda for the College ofTropical Agriculture, UWI, Trinidad in1966. They identified 33 soil types.Atkins (1983) reported by IRF (1991)grouped the 33 soil types for Antiguainto four (4) general categories, namely:

• Deep, alluvial, colluvial soils foundmainly in the narrow valleys of thevolcanic region

• Deep, Kaolinitic clay found mainlyin the central plain

• Shallow soils found in the volcanicregion, and in the limestone regionnorth of St. Johns (extending roughlyfrom the airport in the east toWeatherills in the northwest)

• Complex of shallow and deep soils,found in the northeastern section ofthe limestone region

The soil data map for Antigua is basedon these four (4) soil classes.


13

Deep alluvial soils of finer texture in thevalleys of the volcanic region and thedeep clay soils of the central plains andpockets of the limestone region havegood moisture retention capacity. Plantsin such areas will benefit if the depth toground water provides a reliable supplyof moisture without being waterlogged.

With soil texture and position in relationto ground water conducive to moistureretention, and with soils less prone toerosion, such areas are less vulnerable todrought than areas of steep slopes andshallow soils.

The shallow soils of the volcanic regionare neutral to slightly acidic and welldrained. Moisture retention is relativelyless than in deep alluvial or deep claysoils.

However, moisture retention is improvedin undisturbed areas where significantamounts of organic matter are depositedon the forest floor. Drought effects onsoils in these areas are less severe than indisturbed open woodland areas withsimilar slope and shallowness of soil.

Soil loss from denuded landscape inareas with steep slopes and shallow soilsis significant and are exacerbated bydrought. Soil erosion is accompanied bya gradual loss of soil nutrients and plantcover recovery is slow or may not occur.This characteristic is obvious in areasthat have experienced extensive clearingand grazing.

Generally shallow soils are relativelymore vulnerable to drought and thepresence of shallow soils is thereforeused as a criterion in mapping areas atrisk to drought.

Soils in most of the central plain arewell drained but there are areas of heavyclay and poor drainage. Heavy claysmay hold moisture longer, which ishelpful in dry periods, but restrict cropgrowth in normal conditions.

Soils in the limestone region are mostlyalkaline and are light where there is anoverlay of calcareous sandstones, heavyover calcareous grits and deep and welldrained over calcareous marls (IRF,1991). Well-drained soils lose moisturequickly so that plants in such areas reachwilting point relatively quickly in dryperiods.

As with the shallow soils of the volcanicregion, the shallow soils found in someparts of the limestone region representmajor management challenges for soiland moisture conservation where landhas been cleared or intensively grazed.

Barbuda

Following the work of Hill et al (1966),soils of Barbuda were mapped by theOAS (1992). The OAS soil classificationhas been used in the preparation of thedrought hazard soils data map forBarbuda. This classification places soilsin six (6) series, namely:

• Codrington clay found main aroundCodrington and to its south andsoutheast extending to the coast, inflat areas (2-5 degrees). These soilsare considered suitable foragriculture but are limited byshallowness, stoniness and in somecases salinity

• Barbuda clay loam found in theHighlands in 5-20 degree slopes.Lands are marginal or unsuitable to


14

cultivation. A critical characteristicof these soils is moderate to severeerosion resulting in between 50% tototal top soil loss

• Blackmere clay loam found inapproximately 1/3 of Barbuda, inareas east, southeast and northeast ofCodrington, at the southeastern tip ofthe island, at Goat, Rabbit and Kidislands and at the narrow sand barseparating the west shoreline andCodrington Lagoon. Land in thisseries slopes <10 degrees and ischaracterized by varying limitationsof shallowness, stoniness, salinityand compaction

• Beach sand found at beaches andoverlaying the critical aquifer atPalmetto Point

• Mangrove, Swamp found in themangroves of Codrington Lagoonand in the swamps at the southernsection of the island

• Salina found fringing sections of theCodrington Lagoon and the majorswamp in the south of the island

2.2.4 Vegetation

Antigua

Horwith and Lindsay carried out adetailed vegetation classification forAntigua in 1990s but did not map theirresults. Attempts to obtain or review acopy of the report were not successful.

The Forestry Division has plans toundertake mapping of the island’svegetation. Vegetation zones have beenaltered in the last 20 years from clearing

for residential developments and fromextensive grazing by small ruminants.

In the absence of a detailed up-to-datevegetation classification, mapping anddigitization of vegetation was done usinga combination of sources, along withfield observations. Main sources wereIRF (1991), who adopted earlier worksand the OAS (1992) land use map.

Vegetation categories mapped (seedrought hazard assessment vegetationdata map for Antigua) are:

• Cactus scrub accounting for almost2/3 of the land area and being theparts of the island in which mostsettlement and grazing activityoccur. Cactus Scrub areas vary inpercentage cover of Acacias,Lucaena, logwood and other woodyspecies and in some cases havesignificant grass cover

• Dry woodland mainly found insections of the east coast and pocketsat the northern parts of the island.This vegetation category has beenimpacted severely by grazing andbuilding and is being transformed tocactus scrub in some areas.

• Moist forest found mainly in thevolcanic south and southwest, wherehigher elevations and steeper slopeslimit access and human interference.While moist forest is thepredominant vegetation type of thiszone, areas of drier vegetationassemblages exist. Chances ofmaintaining the remaining moistforests in the volcanic region aregood because land-use threats areless than in forested areas of thecentral plain and limestone regions.


15

Failure to protect remaining forestswill further deepen the island’svulnerability to drought. Since theabandonment of large-scalesugarcane cultivation in 1974Antigua has not experienced anyappreciable gain in new cactus scrubformation that would lead insuccession to dry woodland andeventually moist forests whereprecipitation is adequate. Trendssuggest that the percentage cover ofAcacias and other wooded thornyspecies found in cactus scrub areascould further decline in the nextdecade and, as a result, furtherreduce total forest cover on Antigua.

• Mangrove woodland, Swamp foundin coastal areas. The use ofmangroves as wattle for fish-potsand for charcoal has declined in thelast 20 years. Human impacts aremostly from cutting or filling forcoastal development, whilesignificant damage from hurricaneshave been sustained. Grazing, whichadversely affects other vegetationtypes, has had no direct physicalimpacts on mangroves and swampvegetation.

Barbuda

Barbuda’s vegetation has been mappedfor this assignment (see drought hazardassessment vegetation data map forBarbuda) using the following categories:

• Dry woodland covering theHighlands, areas at the northernsection of the island and at the westcoast sand bar separating the seafrom the Codrington Lagoon.

• Cactus scrub covering most of therest of the island.

• Coconut plantation in the PalmettoPoint and near Coco Point.

• Mangrove fringing areas of theCodrington Lagoon.

• Salina vegetation fringing theCodrington Lagoon and Goat IslandFlush.

• Swamp vegetation.

2.2.5 Soil Water Deficiencies

OAS (1992) provides estimates ofevapo-transpiration and irrigationrequirements for the Green Castle andCoolidge regions of Antigua and theCodrington region of Barbuda. Based onthe results irrigation would be requiredfor the months of February and March,June and July for the three areas, tocounter moisture deficits resulting fromhigher evapo-transpiration rates.

While actual evapo-transpiration ratesare not available to most farms, crop andlivestock farmers and ornamentalgardeners are very much aware of therate at which plants reach their wiltingpoint in shallow soils where little or nowater is available during dry spells.

Deficiencies in soil water is readilydiscernable by a deteriorated “brown”landscape, particularly obvious in areasof extensive grass cover over shallowwell drained soils. Even when water isavailable through irrigation, the rate ofsoil water loss increases where waterconservation measures such as mulchingor the use of windbreaks are not used.


16

Where soil water loss leads to reducedbiomass in grass or plant species that arenormally readily available to smallruminants, goats in particular browsebeyond their normal range feeding oncrops and ornamental plants. In suchcases adverse environmental conditionslead to economic or financial loss toaffected persons.

2.2.6 Water Resources

Antigua

Watershed boundaries for Antigua weremapped using IRF (1991), who quotedMcMillan (1985) and OAS (1992).According to IRF, eighty-six (86)watersheds were initially defined byHalcrow (1977) and these were reducedto thirteen (13) by McMillan.

These same boundaries have been usedby the OAS (1992) and for thisassessment (see drought hazardassessment watershed data map forAntigua). Each watershed has a defineddrainage system and can be considered ahydrological unit of utmost relevance todrought management.

Watershed 1, which drains to NonsuchBay on the east coast and Watershed 2,which drains to Hanson’s Bay on thewest coast are two of the mostsignificant watersheds for the storage ofsurface water for domestic andagricultural use.

Upland stream-flow at watershedsdraining the southwest volcanic region isless affected by land use, in particulargrazing, than most other watersheds.

Stream-flow is not permanent for allwatercourses in Antigua, although

Cooks Creek that flows throughCreekside maintains water for most ofthe year.

Storage capacities for all municipal andagricultural reservoirs are given on theWatershed map for Antigua andsummarized in Section 2.4.

Wells are mapped using OAS (1992) butthe Water Division of the Antigua PublicUtilities Authority (APUA) has beenreluctant to provide updated informationon water resources and infrastructure forsecurity reasons. For this reason,aquifers for Antigua were not mappedbecause no other source has beenidentified.

Barbuda

Ten watersheds have been identified forBarbuda (see drought hazard assessmentwatershed data map for Barbuda),although boundary definitions are notfinite due to its unique topographicalfeatures. Watershed 1 includes thePalmetto aquifer – considered at onetime to be the best quality aquifer on theisland but has been contaminated bysand mining and grazing.

Drainage from all other watershedsoriginates in the Highlands.

A number of wells are shown on thewatershed data map for Barbuda. Inaddition to these are numerous wells dugand used by individual households notlinked to municipal water supply.

A number of sinkholes exist in theHighlands area. These include sinkholesat Brian Cave and Dark Cave, both withdepth to the water table (J. Mussington,pers. comm.).


17

The above suggests that the fresh groundwater reserves are extensive in Barbudabut poorly managed. There are norecords on the number of privatehousehold wells and pumping isunregulated.

Management of fresh water resources inBarbuda would seem to be a criticalissue requiring immediate attention. Aninitial effort should be the mapping of allprivately used wells. In the longterm twoinitiatives should be considered.

One is a comprehensive investigation offresh water resources; there is noindication that this has ever been done.The other is an appropriate regulatoryregime seeking to manage ground wateragainst contamination from land usesand over-extraction by privatehouseholds.

2.3 Land Use and LandManagement Practices

2.3.1 Crop and Vegetable Farming

2.3.1.1 Major Farming Areas

Antigua

Crop and vegetable farming occur inpockets throughout the island. Some ofthese pockets are located in the narrowvalleys with deep alluvial soils of thevolcanic southwest. Others appear just asoften in the central plains and limestoneregions where the topsoil is less thick.

Apart from valley topography there areno readily discernable spatial patterns tocultivation and there are no farm belts.Precipitation, moisture retention and pHoften determine the choice of crop sothat most of the bananas grown on farms

are planted in the valley below Fig TreeHill, an area receiving relatively goodrainfall and protection from wind.

Most of the pineapples on the island areplanted in the valleys of the volcanicregion where soils tend to be neutral orslightly acidic in contrast to the morealkaline soils of the limestone region.

The moisture-loving banana is planted innumerous household gardens. Mangotrees seem to thrive better in areas ofhigher rainfall and are quite obviousalong the Fig Tree Drive.

One thing noticeable about the locationof farms is the relative distance of somein the volcanic region from the mainroad. In some of these casesinfrastructure costs for water connectionfor irrigation may be prohibitive. Farmsin the central plain and limestone regionsare generally better positioned in relationto the main road and water mains.

2.3.1.2 Type of Crops

The drought hazard assessment land usedata map prepared in this assignmentgrouped crop and vegetable farming andtree crops under the land usedesignation, agriculture.

Under the OAS resources assessmentproject, cultivation uses were detailed bytype and watershed. The approximateacreage for each use was also given.The types of uses are provided below,along with an indication of where cropsare mostly grown.

Reference made to the main locations ofeach category is drawn from OAS(1992) with some slight modifications. Itis assumed that the acreage under the


18

various crops has since changed but thatthe relative distribution of crops amongwatersheds has not changedsignificantly:

• Sugar cane grown mostly inwatersheds 54-62 and 63-66. Forgood yield, sugarcane requiresabundant moisture and deepadequately drained soils. Growing itin these relatively dryer watershedsof the limestone region in areas withshallow soils increases vulnerabilityto drought.

• Cotton grown in watersheds 1, 54-62 and 67-77.

• Coconut grown mainly inwatersheds 2, 4-11, 12-20, 63-66and 78-84. Plants are mostly foundin sandy soils but coconuts growwell in other soils also, as long asthere is an adequate supply ofground water with the water tablebeing 150 – 180 cm (60 – 72 inches)(Weir, 1980). Conditions arefavorable for coconuts in the areasgrown, so that it is perhaps the leastvulnerable to drought amongperennial crops.

• Fruit trees mainly mangoes, 63% ofacreage in watersheds 4-11 and 12-20. Higher rainfall and pockets ofdeep soil in these volcanic areawatersheds are advantageous toperennial tree crops, which requiresoils with good moisture retentionand depth to allow tap rootdevelopment.

• Pineapple grown mainly inwatershed 12-20. Acidic and well-drained soils of this watershed aresuitable for pineapples, which could

be grown in other areas wheresimilar conditions exist. Pineapplesdo not require soils with highmoisture retention and is thereforeless vulnerable than many crops todry conditions.

• Banana grown mainly in watershed12-20 but can be found in householdgardens around the country. Theplant favors the deep fertile soilswith adequate moisture of thevalleys in the volcanic region.Bananas are over 90% water butmoisture deficiencies duringdroughts retard plant growth andfruit development.

• Food crops including yams, sweetpotato and maize, grown in allwatersheds except 3, 78-84 and 85-86. These crops have varying soiland moisture requirements.Vulnerability to drought depends onwhere they are planted;

• Vegetable crops including eggplant,tomato, sweet pepper, beans andokra, grown in all watersheds.Vulnerability to drought is relativeto location, soil type, moisture andother factors.

Barbuda

Food crops are grown in pockets onsoils with limitations such asshallowness, stoniness, salinity or lowrainfall. These limitations suggest highvulnerability to drought.

Pockets of food crops are shown on thedrought hazard land use data map forBarbuda. Food is also grown inPalmetto Point but the area could not bemapped because of insufficient data.


19

It should be understood that shiftingcultivation due to rainfall deficienciesand shallow soils is a feature of farmingon the island.

Shifting agriculture occurs in the lowand highlands, where the practice is tofence an area, then clear and burn thevegetation before planting (J.Mussington, pers. comm.). Areas areabandoned when conditions are nolonger suited to productive farming.

Coconuts are grown in sandy soilswhere the water table provides a reliablesupply of moisture. Vulnerability todrought is low.

2.3.1.3 Farming Practices

Crops unsuitable to some areas are inmany cases planted because land tenurereduces options and choices available tofarmers. However, where crops matchland capability, farming practices inwhich little attention is paid to soil andmoisture conservation increasevulnerability to drought.

2.3.2 Livestock Farming

2.3.2.1 Livestock Population

Table 5 shows the livestock populationin Antigua and Barbuda in 1984. Figuresobtained from the Veterinary Divisionon current livestock for Antigua indicatea significant increase in the goat andsheep populations.

Table 6 shows that the goat populationfor Antigua in 2001 is four (4) times itssize in 1984. Today’s sheep populationin Antigua is also almost four (4) timesthe number for 1984.

Figures provided by the LivestockDivision show significant declines in thesheep, goats and cattle populations inBarbuda to 146, 252 and 29 respectivelyin 2001. This suggests that the impact ofgrazing on the landscape has been less inrecent years.

Table 5 Livestock Population inAntigua/Barbuda, 1984________________________________

Livestock Antigua Barbuda

Cattle 9,992 1,072Sheep 5,619 473Goats 9,319 229Pigs 2,425 12Chickens 19, 554 529Horses 179 184Donkeys 713 215

Total 47,801 2,714________________________________(Source: IRF, as reported in the 1984Agricultural Census)

Table 6 Cattle, Sheep and GoatPopulations Antigua, 2001

Livestock Population______________________________

Cattle 15,364Sheep 21,294Goats 37,995

______________________________(Source: Veterinary Livestock Division)


20

2.3.2.2 Livestock Distribution

Antigua

Grazing areas have been mapped in thisassessment (see land use data map).Grazing designations on the map followthose used by the OAS in its NaturalResources Assessment Project report,1992 and are as summarized:

a) Improved pasture: former cultivatedlands, now managed in most cases(sometimes fenced) to control grazing.Antigua Hay grass (Dichanthiumaristatum) and Seymour grass(Bothriocloa pertusa) are the dominantforage grasses. Acacia and other thornyspecies are maintained at less than 10%cover. Major areas of improved pasturecan be found along the Factory Road, St.Phillips and south and southwest ofCreekside. Improved pastures occur onflat to gently sloping lands.

b) Rough Grazing: former sugar lands,consisting mainly of Antigua Hay andSeymour grass and with Acacia cover inexcess of 20% (OAS, 1992). This formof grazing is the most extensive in theisland’s central plains, occurring on deepas well as shallow soils. Rough grazingis also prevalent the northern limestonearea of the island. Grazing lands are notfenced

c) Mixed Scrub and Rough Grazing:Abandoned sugar lands at the stage ofvegetation succession where Acacias andother thorny scrub are dominant. Thistype of grazing occurs mostly in thecentral plains and limestone region. Italso occurs extensively in the volcanicarea between English Harbour, Isaac Hilland Mamora Bay.

d) Woodland Grazing. Thiscategory is not mapped or describedfully in the OAS report. OAS does makereference to small ruminants grazing onslopes with scant bush cover in volcanicareas. The extent of this form of grazingis however more significant thanimplied.

Large populations of goats (mainly) andsheep graze extensively in the ShirleyHeights/Block House area and onwooded slopes of varying thickness invegetation cover north and west ofFalmouth.

Grazing by goats in rough pastures,mixed scrub or wooded areas alters anddegrade vegetation zones, acceleratessoil and nutrient loss and renders areassusceptible to impacts from drought.

Barbuda

Small pockets of improved pasture aremapped for Barbuda on the droughthazard land use data map. This map alsoindicates a fairly extensive area of thelowlands designated mixed scrub andrough grazing.

Most of the grazing by goats, sheep andcattle occur in this area but these animalsalso range in the highlands. In addition,deer, and feral pigs, donkeys and horsesalso graze the highlands.


21

2.3.2.3 Livestock ManagementPractices

Antigua

Improved grazing occurs on landsowned, leased or rented by farmers, whoshoulder capital and recurrent expensesfor managed livestock operations. Cattleare common to such operations but manyalso manage sheep.

Tethered cattle and sheep representanother form of management withoutfences done by landless or land owningfarmers. There are however, thousandsof goats that are owned by landlessfarmers who exercise little control overwhere the animals graze. In fact, goatsgrazing some of the volcanic slopes arein some cases considered “wild.”

Goat and sheep farmers tend to ignoredamages caused by their livestock tocultivated crops and gardens. They alsoseem to be oblivious to theenvironmental damages caused byovergrazing.

Existing penalties are not effectiveenough to halt inimical grazingpractices. The tradition of impoundinglivestock caught damaging crops andgardens no longer exist because most, ifnot all, the pounds have been abandoned.

Barbuda

Untethered livestock is less of a problemto farms and gardens in Barbuda than inAntigua. Also, the decline in livestockpopulations since 1984 would havereduced the impacts on the landscapeand habitats normally associated withovergrazing. Nevertheless, grazingremains largely uncontrolled. Its impacts

on the vegetation of the highlands,where shallow soils is already aconstraint to plant growth, is an aspect oflandscape and habitat vulnerability todrought that should be of major concern.

2.3.2.4 Markets and Prices

One of the reasons for the significantincrease in the sheep and goatpopulations between 1984 and 2001 isthe existence of a strong local market.The price for mutton and lamb inAntigua is EC$7 per lb retail and liveweight animals fetch an average of EC$3per lb.

The demand for lamb and mutton, alongwith low overheads for managing un-tethered small ruminants and a weakpolicy to deter harmful grazing practices,provide conditions fertile to thecontinued growth of the sheep and goatpopulations in Antigua.

2.3.3 Settlements and Communities

a) Population

The population of Antigua decreasedfrom 64,129 in 1970 to 58,114 in 1991,while that of Barbuda increased to 1,241from 1,071. Population declined in allparishes but major losses occurred in St.Phillips, which lost more than half its1970 population and accounted for 36%of total population decline in Antigua.

Other parishes with significant declineswere St. Mary’s 25% and St. Paul’s,16% of total population loss between1970 and 1991.

Appendix 4 shows a breakdown of the1991 population and population densityby parish. Population density for


22

Antigua is 538 persons per sq. mile butin St. John’s City, the density is 7,419persons per sq. mile.

The high population density for St.John’s City makes it relatively morevulnerable to drought than othersettlements with respect to waterdemand and supply.

Many households, particularly in areassuch as the Point, Gray’s Green andOvals do not have much space for aboveground water storage and therefore mustrely almost completely on piped waterwithout the benefit of storage, a criticalrequirement when water must berationed.

It is interesting that while the populationdecreased, the number of householdsincreased from 15,405 for both Antiguaand Barbuda in 1970 to 18,808 in 1991.This correlates with the visible growth innew housing within the 20-year period.

Data on new housing, which should beavailable from the DCA, is not reliablebecause a significant number of newhouses were constructed withoutplanning permission in the period.

Given the decline in national populationfigures, population growth per se doesnot adversely affect the country’s abilityto deal with drought. However,continued entrance of migrant workersto Antigua can increase vulnerability inareas of St. John’s poorly equipped withwater storage infrastructure. These arethe areas that new migrant workers areattracted to because of more affordablerents and a convenient location todowntown St. John’s.

In addition, the growth of newhouseholds is being accompanied by percapita increases in water use as thematerial well being of residentsimproves.

b) Settlement Distribution

Settlements are distributed island widebut most of Antigua’s population lives inthe central plains and limestone region.With the exception of John Hughes andSawcolts, traditional settlements in thevolcanic region are located mainly in thevalleys or foot of slopes. Traditionallythe village developed as a core entitysurrounded by farmlands. Crop andvegetable farming were for most personsthe primary agricultural activity linkedgeographically and socio-economicallyto households.

Subsistence livestock farming has nowreplaced crops and vegetables as thefarming activity in which householdmembers can be involved while workingfull time at other jobs. This is partlyresponsible for the increase of goat andsheep populations and the devastationthat leaves the landscape more prone todrought impacts.

c) Residential Development Trends

Residential trends are changing therelationship between village and farm inAntigua. The same is not yet true forBarbuda.

In Antigua, government’s policy ofproviding liberally sized housing lots(1/2 to 1 acre lots) often below marketvalue is one of the factors thatprecipitated a trend towards lowerdensity residential development and the


23

growing urbanization of formerlycultivated lands.

Another factor is the increase invehicular ownership allowing mobilityto the population and less dependence onpublic transportation. Infrastructure toserve low-density residential growth ismore costly than for compact settlementsand has been subsidized by governmentto a large degree.

The implications have not been studiedneither with respect to the financialburden on government or the long-termeffects on land and environmentalmanagement.

With regard to this assessment, the costof infrastructure for water distribution isa factor that impacts on the country’scapacity to manage water needs in dryperiods and more so in droughtconditions.

2.3.4 Hotels and Tourist Zones

a) Distribution

Tourism is Antigua’s main foreignexchange earning industry. Hotelsconstitute the major tourism sub-sectorbut cruise and yachting tourism alsocontribute significantly to tourismearnings and jobs.

The number of properties and rooms inAntigua and Barbuda is shown inTable 7.

Beach hotels and other vacationaccommodation constitute the majorcomponent of the tourism plant’s land-based accommodation. Major tourismzones are Antigua’s north coast, FiveIslands’ peninsula (including Deep Bay

and Hawksbill Bay, Jolly Beach/JollyHarbour), Long Bay Coastline andFalmouth Harbour/English Harbour.

Table 7 Tourism Accommodationin Antigua and Barbuda, 2001

Accommodation # Properties # Rooms_________________________________Antigua

Hotels 40 2644Guest Houses 8 59Apts/Cottages/Villas 42 291

Sub total 90 2994

Barbuda 4 111

Total 94 3105________________________________(Source: Antigua Hotels & TouristAssociation)

Table 8 Distribution of Hotel Propertiesby Watershed

Watershed # Properties # Rooms________________________________

Antigua

• 67-77 (Northcoast) 31 1104• 78-84 (Five Islands Peninsula) 6 525• 4-11 (Jolly Harbour/ Jolly Beach) 6 704• 27-46 (Falmouth/English Harbour/St. James 8 292• 54-62 (Longbay Coastline) 4 220

Other 45 149Sub Total 90 2994Barbuda 4 111Total 94 3105


24

Since the effective management of landuses within the hydrological unit of thewatershed helps to mitigate vulnerabilityto droughts, the distribution of hotelproperties and rooms by watersheds isprovided in Table 8.

Ninety five percent (95%) of touristaccommodation rooms fall in five (5)watersheds, two of which are in thevolcanic region, two in the limestoneregion (except for properties in St.John’s) and one in the central plain.

In general hotels do not affect uplandrun-off or erosion, since most are locatedat the coastline. Rather, hotels can beaffected by upland run-off and erosionproblems resulting from other forms ofland use. Such problems may includepollution and turbidity impacts onbathing areas.

Overgrazing can cause both. It alsodegrades the landscape, which adverselyimpacts the quality of the visitorexperience, particularly during droughts.For example, Watershed 27-46(Falmouth/English Harbour/St. James)with its 292 rooms has one of the largestpopulation of goats and sheep on theisland and perhaps the highest density ofgrazing and browsing small ruminants.

Portions of the landscape seen from thescenic drive to historic Lookout(Shirley’s Heights) and Block Househave been devastated. Drought now hasa more telling effect on the area.

On the other hand, demand for water byhotels, yachts and cruise ships hasgrown. Per capita water use by stay-overhotel visitors is significantly more thanresident demand; up to 300 gals / day

/person in one study against an averageof <100 gals/day for residents.

2.4 Infrastructure

2.4.1 Dams and other StorageReservoirs

Antigua

Surface water in Antigua is stored in ten(10) medium to small reservoirs and 550ponds and earthen dams, with a totalcapacity of approximately 6 million cumeters (6000 acre ft or 1.6 billionimperial gallons) (Ministry of Trade andPlanning, Antigua and Barbuda, 2000).

The location and capacity of agriculturaland municipal reservoirs are shown inTables 9 and 10 respectively, and alsoshown on the drought hazard watershedsdata map for Antigua.

Table 9 Location and Capacity ofAgricultural Reservoirs, Antigua

Reservoir Location Storage(cu. meters)

BethesdaRed HillGunthorpes#4Gunthorpes#5Oliver’s DamASF DamsLangfordsGaynorsBendals

Total

BethesdaRed HillGunthorpesGunthorpesOliversSugar FactorySugar factoryCollinsBendals

537,00046,00026,00067,00059,000

116,000110,00032,00023,000

1,016,000

(Source: Ministry of Trade andPlanning, Antigua and Barbuda)


25

Table 10 Municipal Reservoirs, Antigua

Reservoir DrainageArea (ha)

SpillwayElevation(m)

StorageVolume(cu.meters)

PotworksCollinsWallingsFig TreeDunningsBreak-necks #1Break-Necks #2HamiltonBodyPonds/Fisher

Total

2,4301724472

146

56

48175

779

3,922

20.4211.89

150.88112.7830.38

73.15

39.9346.94

27.43

4,142,000342,00051,6802,280

136,040

20,50

76,380104,120

101,460

4,976,480(Source: Ministry of Trade andPlanning, Antigua and Barbuda)

2.4.2 Wells

Antigua

Ground water in Antigua is drawn fromabout 50 active wells, located in severalwell fields, as given in Table 11.

Most of the municipal and agriculturalwater in Antigua are stored in six (6)watersheds (Table 12). According to theMinistry of Planning (1997), thesewatersheds also account for 80% ofground water yield from wells.

Table 11 Major Well Fields of Antigua

WellField

#wells

Location Capacity(igpd)

TargetArea

Bendals 13 Bendals n/a Ben-dalsValley

TheValley

20 BlubberChris-tian,Roses,OragneValleys

n/a n/a

CadesBay/Clare-mount

5 CadesBay/Clare-mount

30,000 Old Road,UrlingsJohn-sonsPoint,CrabbHill

Follies 5 JohnHughes/Sweetes

40,000 N/a

BristolSprings/Collings

7 East ofCollingsReser-voir

150,000 Willi-kiesNew-fieldSt. Phil-lipsMillReefBethes-da

(Source: Ministry of Trade andPlanning, Antigua and Barbuda)

Table 12 Water Storage and Well Yieldby Major Watersheds, Antigua

Watershed Storage Ground Water (cubic meters) (mil. cu. m/yr) Agri. Municipal_______________________________________

1 30,600 4,010,000 220,0002 200,400 278,000 390,0003 334,500 - -4-11 9,200 166,000 610,00047-53 540,000 - -63-66 33,400 - -

Total 1,148,100 4,454,000 1,220,000_____________________________________(Source: Ministry of Planning)


26

Barbuda

Well water is supplied by APUA tohouseholds in the central section ofCodrington. Information on the numberof households connected to mains supplyor on the volume of water supplied wasnot obtained.

Numerous private wells exist and thewater is used for bathing, flushing toiletsand for watering gardens. The waterquality is not monitored. Water fordrinking and cooking is taken mainlyfrom cisterns, even for households withmains supply.

Public wells in the lowlands (in oradjacent to Codrington) are equippedwith concrete troughs, which are usedmainly for watering livestock. Wellssunk at the Palmetto aquifer are used forfarms and livestock.

2.4.3 Desalt and other WaterTreatment Plants

Two desalination plants, both located atCrabbs Peninsula, produce water for thenational supply network. A flashdistillation plant owned by governmentproduces 2.8 million gpd and a reverseosmosis plant, owned by a privatecompany, produces 800,000 gpd.

The government owned desalinationplant was commissioned and built afterthe 1983-84 drought when PotworksDam, which provided over 50% ofmunicipal water, went dry.

Desalinated water currently meets 62%of Antigua’s municipal water needs.This helps to cushion the country fromwater related shocks associated withdroughts but production costs are muchhigher than other sources.

Production costs cited by the Ministry ofPlanning, based on information from theAntigua Public Utilities Authority(APUA), are:

• Ground water: US$2.50 per cu.meter

• Surface water: US$3.00 per cu.meter

• Desalinated water: US$4.70 per cu.meter

Water production cost by APUA is far inexcess of water revenues. This is partlythe result of the high cost of desalinatedwater but government’s policy to keepwater rates in check is part of the reason.

Predictions by the Ministry of Planning(1997) shows a continued negative gapbetween water revenues and productioncosts up to the year 2020, averaging overUS$8 million per year.

Water subsidies cannot be sustainedforever, so that investment to increaseground and surface water supplies isbeing considered. This would help toreduce the negative gap betweenrevenues and production costs but wouldnot be the full solution.

The uncertainties over future climatechange, variable precipitation and thecontinued growth in the demand forwater means a continued reliance ondesalination during average rainfall andmore so during periods of drought.

Private Reverse Osmosis Plants

Several hotels now have reverse osmosis(RO) plants. Some were installed as aresult of water shortages experienced inpast droughts. Curtain bluff has a


27

50,000 gpd RO plant. An RO plantlocated on the Jolly Harbour propertybut operated by an independentcontractor has a design capacity for120,000 gpd but produces and sells anaverage of 70,000 gpd to the JollyHarbour Resort complex. The supplieris able to offer water at lower rates thanAPUA, suggesting that APUA should beable to produce desalination water atlower than its current costs.

Feed water to supply RO plants is takenfrom the sea in most cases. At JollyHarbour 20% of the feed water (35,000gals per day) is drawn from a brackishwell on the property (Ivor Jackson &Associates, 2000). The rest comes fromthe sea.

If the yield of the well drops duringperiods of hydrological drought a higherpercentage of feed water is drawn fromthe sea at the marina basin. RO plantstherefore reduce the vulnerability ofhotels to meteorological andhydrological droughts.

2.4.4 Wastewater Treatment Plants

Few hotels on the island have watertreatment plants that allow the reuse oftreated wastewater. Jolly Harbour has aplant with design capacity to treat500,000 gpd. The current wastewaterload at Jolly Beach Hotel and JollyHarbour Villas – the main users of theplant – is less than 120,000 gpd at highoccupancy and less at lower occupancy.The treated wastewater is used to irrigatean 18-hole golf course. Thissignificantly reduces the reliance onpotable water for irrigation and bringsthe cost of water down.

2.4.5 Irrigation Systems

Agriculture

The acreage of cultivated land thatcurrently has access to irrigation watercould not be determined. Water sold byAPUA at the agricultural rate has beenaveraging 198,000 cu. m per year, basedon figures provided by the Ministry ofPlanning.

The high cost of municipal water usedfor agriculture acts as a deterrent toirrigation.

Hotels and Golf Courses

Most hotels use some form of irrigationsystem for landscaping. Smallerproperties use either hand held hoses ormoveable sprinkler systems. Largerproperties may have pop-up sprinklersystems or in some cases micro-irrigation systems (drip) using simple“soaker” hoses.

Unfortunately, there is no available dataon the percentage of properties using onesystem or the next. Environmentalaudits done for a number of hotels in theregion indicate significant wastage ofwater from inappropriate water use,including poor irrigation practices.

Where selected plants do not match soiland microclimatic conditions thetendency is to compensate by excessivewatering. This happens in Antigua,although the extent is not known, andwill continue until properties adopt moreconscious water conservation methods.

Water requirements for golf courses canbe in excess of 150,000 gallons per dayfor 18-hole courses, depending on the


28

quality sought for putting greens andfairways. The course at Jolly Harbouruses between 90,000 and 125,000gallons/day. The actual amount dependson rainfall.

Fortunately, most of this is met bytreated wastewater, which is adequate aslong as occupancy levels remain above70%. Except for periods when lowoccupancy levels fail to generate enoughwastewater volume, the golf course doesnot make any significant demand onnational water supply.

2.4.6 Water Distribution

Variable pressure in water distributioncreates problems for consumers. Highpressure in some areas causes frequentleaks on the mains and consumerdistribution lines. Low pressure in otherareas results in inadequate flows andinconvenience to users.

2.4.7 Roof Catchment and StorageCisterns

Roof catchment and storage in concretecisterns cistern, metal or plastic tanks ormetal drums is a traditional and acceptedpractice, particularly for homes. It isnow a planning requirement for newdevelopments to make adequateprovision for water storage on property.

The standards for residences and hotelsnow being used by the DevelopmentControl Authority (DCA) are:

Residences: 10 gallons per sq. ft. of roofarea.

Hotels: 10 gallons per sq. ft. of roof area.Where hotels use reverse osmosis (RO)plants to augment water supply, the

minimum standards for roofcatchment/storage are less rigidlyapplied.

2.5 Water Supply and Demand

Water supply for Antigua and Barbudaaverages 4.5 million cubic m per yearfrom sources as shown in Table 13:

According to the Ministry of Planning42% of total water supply wasunaccounted for, 31% was used bydomestic consumers, 17.7% bycommercial and hotel users and 4.4% byagricultural users.

The Ministry of Planning in its 1997climate change water resource sectorstudy predicts that total water demandwill be:

Year 2000: 4.2 million cu meters/yr 2010: 5.8 million cu meters/yr.

Table 13 Water Supply,Antigua/Barbuda, 1996

Source Volume % Total (Million cu. m/year)

_____________________________

Ground water (APUA) 0.6 13Surface water (APUA) 0.9 20Private roof catchment(Estimated) 0.1 2Private dams (Estimated) 0.1 2Desalination (APUA) 2.8 63

Total 4.5 100_______________________________(Source: Ministry of Planning, 1997)


29

It is presumed that the available supplywould increase by reducing the amountof water that is lost from the system.

Assumptions made by the Ministry ofPlanning are that the population wouldgrow to 72,300 by 2000 and 81,000 by2010, and that per capita domestic waterconsumption would remain at 0.63 cumeter/day through to 2010.

These projections require carefulmonitoring because there is a degree ofuncertainty associated with waterdemands – one such reason being thedifficulty in predicting growth in thetourism sector.

Water demand management therefore ismajor issue for drought mitigation fortwo reasons:

• Insufficient information onunaccounted for water.

• High production costs and hencehigh consumption costs, which arebelieved to mask true demand fromthe agricultural sector.


30

_________________________________3.0 IMPACT AND

VULNERABILITY


31

3.1 Historic Drought

This section of the report reviews theimpacts of past droughts on the islandsand the response to the adverse effectsexperienced.

3.1.1 Description of Drought Events

Based on the meteorological definitionfor drought described in Section 1.4.1, atotal of eight (8) droughts occurred inAntigua and ten (10) in Barbudabetween 1960 and 2000 (see Table 13).

Table 13 Drought Years in Antigua/Barbuda 1960 – 2000

Year Rainfall (Inches)Antigua Barbuda

________________________________

1966 27.52 12.891967 29.14 22.871968 25.09 27.791971 -- 26.371973 25.98 --1977 -- 25.651983 22.31 20.67*1990 -- 24.171991 30.49 23.641994 30.49 25.041997 26.46 --2000 n/a 23.30 (Source: Met Office, 2001)* Rainfall for December not included

Between 1966 and 1968 there were threeconsecutive years of rainfall below 30inches in Antigua. However, the 1983drought, which extended into 1984, wasthe one that most people in Antiguaremember.

It lasted from January 1983 to August1984. In this 18-month period, monthly

rainfall exceeded three inches twice, inAugust of 1983 and March 1984. Totalrainfall for 1983 was 22.31 inches andfor the first eight (8) months of 1984,16.48 inches. The drought was ended by8.54 inches of rain in September 1984.Between September and December1984, 29.38 inches of rain wererecorded.

Because of its severity and impacts, thisdrought could be ranked as the “droughtof record” for Antigua, meaning thedrought remembered as having thegreatest impact on the island. Thisdrought and its impacts are described inthe following pages. The impactsdescribed are mainly for Antigua.

Rainfall records indicate that Barbudaexperienced its severest drought in 1966during the period, when rainfall for theyear was 12.89 inches. Unfortunately, areview of the impacts of this droughtwas not possible during this assessment.

3.1.2 Drought Impacts

3.1.2.1 Environmental Impacts

a) Watershed and HabitatDegradation

Watershed Impacts

Antigua received only 22 inches of rainin 1983, Barbuda less up to November ofthat year. By the time the droughtentered its second year, marked changesin watershed and vegetation conditionswere obvious.

Drought impacts were particularlysevere in watersheds, such as 27-46, 47-53, 54-62 (see watersheds data map,Antigua) where plants with shallow root


32

systems on shallow soils were among thefirst to be affected by deficiencies in soilwater.

For undeveloped areas of suchwatersheds seeking to re-establish aneco-system integrity after years ofcultivation and charcoal burningsignificant losses in biomassproductivity were experienced. Thisoccurred even in thorny woodlandvegetation associations, where acacias(Acacia spp.), logwood (Haematoxylumcampechianum) and wild tamarind(Leucaena glauca) species are welladopted to shallow soils with lowfertility and moisture deficientconditions.

No studies were made of soil conditionsduring the drought. It is assumed thatmoisture deficiencies eventually led toreduced soil fertility. The combinedeffect of water deficiency on shallow aswell as deep root plants was progressivedecline in the plant conditions.

Leaf and stem loss in herbaceous andwoody plants were followed by plantmortality in certain species. As plantswilted and died, canopy cover decreasedin wooded areas and the landscapegenerally became visibly brown, dustyand harsh looking.

In Antigua/Barbuda, prolonged periodsin which the landscape is visibly stressedare linked to hard-times; a dispositionthat can be traced to a time when rainfed agriculture provided the majorsource of income and livelihood for ruralfamilies.

The reduction and, in some cases,disappearance of plant cover exposedsoils to the erosive force of winds and

water when it eventually rained. Soillost during the drought and thesubsequent reduction in soil fertility,interrupted the process of ecosystemevolution occurring in watershedhabitats prior to the drought event.

Habitat Degradation

In Antigua/Barbuda it is difficult todistinguish between habitats for wildlifeand rangelands for wandering anduncontrolled livestock. For example,because parts of the landscape of thearea delineated as Nelson’s DockyardNational Park is steep and not readilyaccessible for agriculture and logging forcharcoal they provide reasonableseclusion for birds, amphibians (frogs)reptiles (lizards) and mammals to reside.

The Highlands of Barbuda is a criticalhabitat for the Fallow Deer (Damadama) and other mammals.

However, these areas also serve asrangelands for extensive grazing (oftentimes intensive) of goats and sheep.Livestock population densities in theseareas are in excess of what is consideredsustainable for like ecosystems.

Before the drought, habitats werealready susceptible because ofovergrazing and thus suffered doublywith the extended periods of belownormal precipitation. Habitat conditionsthen deteriorated for both wildlife andlivestock in critical watersheds.

One constraint in assessing habitatimpacts from grazing is the absence ofdetailed listings of plant speciespreferred by goats. Unlike cattle andsheep, goats browse (rather than graze)normally on various herbaceous plants


33

and woody shrubs along withornamental plants if they gain access tohousehold gardens.

Since biomass production of grass usedby livestock in Antigua declines fasterrelative to many species used by goats,grazing livestock are likely to reach thecritical threshold of nutritional stressearlier than goats.

Thus, of the 47,801 livestock said to bein Antigua and 2,714 in Barbuda in1984, goats are likely to have been theones with lowest mortality from thedrought.

It is not known if these figures reflectedmortality associated with the drought orif most of the livestock mortalityoccurred after the field surveys for thecensus were done.

3.1.2.2 Economic Impacts

a) Agriculture

Food Crops

The 1984 agricultural census of Antiguaand Barbuda identified 6,000 farmers(70% of which were part time) in thecountry, 4,658 farms, and a total acreagefarmed of 6,225 acres. (IRF, 1991).Landless farmers operated about 50% ofthe farms and 40% of the farms wereunder two acres. There were 66 farms inAntigua that were larger than 10 acres.

It is assumed that these figures representthe existing situation at the start of thedrought. Also of importance to theunderstanding of drought impact is thebreakdown between commercial andnon-commercial production, namely:

• Thirty percent of production wasdone for home use only

• Thirty-three percent for home usemainly

• Thirty-seven percent for commercialuse, mainly for domesticconsumption

A range of food crops and fruitscomprise most of the agriculturalproduction. At the time of the droughtcultivation of crops for export, such assugar cane and cotton had beendiscontinued.

Data from the census indicate significantdeclines in produce after 1984 for somecrops, such as bananas (685,000 lbs1984, 185,000 lbs, 1988), pineapples(448,000 lbs in 1984, 278,000 lbs in1988), sweet potatoes (1,076,000 lbs in1984, 482,000 lbs in 1988).

On the other hand, crops such asmangoes (401,000 lbs in 1984, 1,322,000 lbs in 1988), beets, grapefruits,limes and eggplants showed markedincreases after 1984.

The census data does not correspondwith anecdotal accounts in all cases. Forexample, one would expect that bananabeing a crop heavily dependent on water,would have suffered declines in yieldbetween 1983 and 1984.

Most farms in Antigua/Barbuda were atthe time of the drought (and still are)rain dependent. The number of irrigatedfarms was not known for the time.

As a result, widespread crop failure wasreported as a consequence of thedrought. Even for farms with access to


34

potable water, rationing of suppliesmeant that priority for scarce water wasgiven to hotels and households.

Livestock

The number of livestock that died duringthe drought was not determined.Residents however remember images ofcattle and sheep lying along the wayside.The rains that ended the drought alsotook the lives of several cows around thePotworks Dam area.

It seemed that some of the cattle weretoo weak from malnutrition to avoid thefloodwaters and were washed along thewatercourses.

The drought affected the health, weight(hence marketability) and productivity oflivestock. Hot weather caused heatstress, which is said to reduce fertilitythrough sperm damage. Hot weatheralso affects libido in male animals,decreases milk production in cows andkills chickens (Dr. Paul Cadogan, 2000).

Animals also suffered from dehydrationcaused by shortages of water, whendams dried and water flowing throughthe pipes was not enough to meet thegrowing demands.

In some cases, livestock farmers killedtheir animals to avoid death from theeffects of the drought. In other cases,animals that died from drought effectswere butchered and sold without theknowledge of consumers, causing greatalarm when this was discovered.

The economic impacts could thereforebe summarized as:

• Setbacks to the development of smalland large herds due to the drought’seffects on the productive capacitiesof animals.

• Reduction of weight and hencemarketable volume of meat becauseof under-nourishment.

• Reduced marketability of animalsand their products due to the mal-nourished appearance of animals andthe feeling (real or imagined) thatthey were afflicted by diseasebrought on by the drought.

• Reduction in the supply of localmeats, creating more dependency onimported meat products.

• Significant income loss to livestockfarmers.

Absence of Drought Insurance

The economic impacts on agriculturefrom drought were compounded by theabsence of drought insurance for cropsand livestock. Insurance is lacking forthree key reasons:

• Insurers do not perceive this as afeasibly investment of resources,given the relatively small sizes offarms and livestock herds.

• Even if crop and livestock insurancefor drought was available, smallfarmers most likely would not haveseen the need. With the small sizeand subsistence nature of manyoperations, paying insurancepremiums would have beenconsidered an additional financialburden.


35

• Crop insurance is not integral to thesmall farm culture inAntigua/Barbuda.

In the absence of being able to fileclaims for crop damages and/or loss,farmers had to absorb their own financiallosses. The experience was difficult andstressful for many farmers and in somecases it dampened the enthusiasm forfuture investment in agriculture.

b) Tourism

Landscape, Product and Climate

Antigua/Barbuda’s tourism is promotedmainly on the strength of the quality ofits beaches, climate and sea. Althoughnot featured prominently in promotionalliterature, the scenic qualities and theoverall attractiveness of the landscapeare also critical to an enjoyable visitorexperience.

Drought adversely affects the quality ofthe biological landscape (that is theliving landscape of plants and animals)and the physical (non-living) landscape;the latter due mainly to the heat and dustassociated with extended periods of lowprecipitation.

The general quality of the visitorexperience was affected by relativelyhotter and drier conditions, a degradedlandscape and a less friendly dispositionof residents under the stress from thedrought. Uncomfortable andunattractive environmental conditionswould have impacted negatively ondecisions to take tours and hikes.

While these impacts may not havecaused tourists to shorten their vacation,they could possibly have impacted

negatively on decisions to make returnvisits. The potential future income lostfrom return visits or from potential visitsfrom friends who might have beeninfluenced to visit if their experienceswere more positive, cannot bedetermined. Failure to quantifyeconomic loss in this case, however,should not reduce the significance ofdrought effects on the tourist product.

Water Shortages

The hotel sector, like all other sectorswas affected by water shortages.Tourists are known to be highlyintolerant of water deficiencies. Apartfrom the inconvenience, the implicationsfor hygiene and health figureprominently in how they value thevacation experience.

Although priority was given to hotels inwater rationing, all properties werereportedly affected. Most propertieslacked back-up water storage facilities ofminimum standard size and even wheresuch facilities were adequately sized inaccordance with building standardscapacities were irrelevant in theextended period of very low rainfall.

The economic effects from the droughton hotels resulted from:

• Shortening of vacation because ofwater problems and relatedinconveniences.

• Cancellations by potential guestsbecause of the water problemsrevealed to them by travel agents orthe media.

• Cost for purchasing water.• Loss of income from all of the

above.


36

Impacts on Property Landscapes

Properties reported damage and in manycases loss of ornamental plants. Suchlosses would have been morepronounced in exposed areas and inrapidly drained soils. The latter wouldinclude the sandy soils of some coastalproperties.

Loss of Revenue to Hotels

Hotels incurred revenue loss. It wouldappear, however, that records on actualamounts are not available. Because ofchanges in hotel management since1984, reliable estimates on revenue losscould not be obtained.

The existence of the Crabbs desalinationplant in the more recent drought in 1995effectively reduced impacts related todomestic water supply.

Effects on Workers

The income loss to hotels also translatedinto hardships for hotel workers. Somewere laid off during the period.

Restaurants

Drought impacts also extended to therestaurants. Restaurants serving localcuisine were affected by shortages inagricultural produce and meats. Theywere also affected by water shortages.

c) Settlements

The effects of the 1983-84 drought onhouseholds was as severe and, in somecases, more so than hotels. Many houses

went without piped water for weeks at atime.

Drought conditions in 1983-84 affected:

• Household income• Sanitation and Health• School and work

(Water was actually barged fromDominica during the more severeperiods of the drought and used toaugment supplies to homes and hotels).

Household Income

Households where the main incomeearners were farmers (crop or livestock)experienced severe cuts in income andsuffered from shortages in food.Generally, the reduction in crop yield,along with deteriorated livestock healthand livestock mortality adverselyaffected food supply nationally.

Sanitation and Health

Extreme water shortages, such as thosethat occurred in periods of the 1983-84drought, impact hygiene and sanitation,which in turn affect health. There arehowever no available reports on theimpacts on the health of the populationfrom the drought.

School and Work

Water shortages also createdinconveniences to workers and schoolchildren of households, where availablewater had to be rationed between varioushousehold uses, for example, laundry,bathing, cooking, livestock.

3.2 Future Vulnerability


37

3.2.1 Agriculture

Crops

At the time of the 1983-84 drought,Antigua relied on surface waterreservoirs to provide most of its potablewater. Water supply was readilyaffected by meteorological drought andthe country was highly vulnerable duringperiods of low rainfall.

Desalination now accounts for 62% ofpotable water and generally householdsand hotels have become significantlyless vulnerability to deficiencies inrainfall. However, vulnerability remainshigh for crop farming because manyfarmers perceive the cost of water as oneof the factors working againstprofitability.

A heavy reliance is still placed onrainfall to provide the moisture neededby crops, even when water from mains isavailable for irrigation.

Variable climate and precipitationremain over-riding critical naturalfactors contributing to the vulnerabilityof crop farming to drought. Practices(human factors) contributing tovulnerability include:

• Poor crop location in relation to soiland other factors that restrict plantgrowth and crop yield. Failure tomatch crops to land capabilityremains a problem. OAS producedland capability maps for Antigua andBarbuda in 1992. These should beused as the basis for building theawareness of farmers for better cropselection, along with improved soiland water conservation practices.

• Cost of irrigation.

• Water conservation practices –mulching is being used at ClaremontFarms to conserve moisture in thegrowing of pineapples. A micro-irrigation (drip) system is used toconserve water. This is one of agrowing number of examples wherewater conservation is beingpracticed. Unfortunately, mostfarmers do not seem inclined to usesuch conservation methods. The costof mulch (organic or plastic) and thecost of water saving irrigationsystems may act as deterrents tobetter conservation practices.

• Soil conservation practices –mulching not only conservesmoisture but also protects soil fromthe forces of erosion. Soil particlesdo not bond adequately in theabsence of soil moisture. As a result,erosion accelerates during periods ofdrought. Sloping terrain and areasexposed to wind are mostly affected.Nutrient loss accompanies erosion,so that crop yield is affected.Vulnerability can be reduced ifconstraints to wider use of mulch byfarmers are removed.

• Absence of drought insurance –Farmers will continue to shoulderfinancial losses resulting fromdrought, because it is unlikely thatlocal insurance companies willprovide drought insurance for cropsin the near future. Considerationshould however be given to thedesign of a drought relief program bygovernment, which could seek toaccess donor funding to assistfarmers.


38

Livestock

Overgrazing. Overgrazing is perhaps theprimary contributing factor to Antiguaand Barbuda’s vulnerability to drought.Reducing vulnerability in this respectrequires drastic reduction in the goatpopulations and rigid control over wherelivestock are allowed to graze.

To achieve these aims without causingunbearable economic dislocation andhardship to livestock farmers willrequire strategic planning, broad-basedconsultations with stakeholder groupsand public awareness to build publicsupport for actions to be taken.

Such actions should evolve from anational program and campaign toreduce the impacts of goats on thelandscape, environment and crops. Theprogram should have two primarycomponents:

• Population control – seeking toachieve population grazing densitylimits that can be sustained.

• Restoration of forest or landscapeareas that are displaying desert-likecharacteristics due to overgrazing.

Adequate resources would need to beapplied for research, institutionalbuilding, public awareness and policyformulation in the implementation of theprogram.

Policy Issues

Reducing vulnerability to drought forboth crop and livestock farming willrequire a number of critical policyinitiatives, including:

• Incentives to achieve better soil andwater conservation practices.

• Reduction in water rates forirrigation, through subsidy or othermeans.

• Development of adequateinstitutional infrastructure andcoordinating mechanisms fordrought planning and management,drought preparedness and droughtwarning. (This is relevant to othersectors, also, including tourism andsettlements).

• Support for drought related research,monitoring, planning and mitigation.

• Regulation of livestock access topublic owned lands.

• Stiffer penalties for livestock ownersfor damage to crops and gardens.

3.2.2 Tourism

After the 1983-84 drought a number ofhotels installed reverse osmosis (RO)plants and have become less vulnerableto droughts as a result. Most hotels,guesthouses, villas and other forms ofvisitor accommodation properties stilldepend on APUA for most of theirpotable water supply.

Although the existence of thedesalination plants makes water supplymore dependable, properties without thecapacity to produce most of their potablewater are still affected by rationing.

The extent of their vulnerability couldnot be determined in this assessmentbecause a detailed survey of on-sitewater infrastructure, including


39

production plants, roof catchment andstorage capacity was not possible.

Based on discussions with a number ofhotel managers, water conservationpractices by hotels are limited to the useof water saving toilets and showerheads,which have become standard for manymanufacturers of bathroom fixtures.

A lot of water is believed to be stillwasted on properties due to leaks, poorirrigation practices, absence of a reliablelevel of wastewater treatment to allowreuse for landscaping and failure tometer water for different major propertyuses so as to detect waste.

An inventory of tourism properties,including marinas and golf courses,should be considered to determine theirpreparedness to deal with futuredroughts. The inventory could be donewith the involvement of the AntiguaHotels and Tourism Association(AHTA) and should cover among otherthings:

• Sources of water supply• On-site water production capacity

where appropriate• Onsite water storage• Irrigation systems• Water conservation practices• Methods for detecting water loss

from leaks and faulty equipment

3.2.3 Settlements

Antigua

Like hotels, water supply to settlementshas improved with the use of desalinatedwater by APUA. Vulnerability has beenreduced with respect to water supply butmost settlements are still affected by

water rationing during droughts. This isexpected to continue in the future unlessAPUA decides to increase waterproduction from desalination on its ownor with the use of private contractors.

The relatively higher cost of producingdesalinated water, compared to groundand surface water, is a major constraintto providing water that would not beaffected by variable rainfall. High costnotwithstanding, a commitment toincreasing desalinated water productionmay be required to reduce thevulnerability of settlements as waterdemands increase in the future.

In Antigua, water loss from evaporationand seepage at surface reservoirs is anissue without a cost-effective solution. InNevis, where potable water is stored intanks, such loss from evaporation andseepage does not occur.

Despite the need to ration water indroughts, water is frequently lost due toleaks from supply mains that APUA isoften slow to repair. The occurrence ofthis in the future will increase thecountry’s vulnerability to drought.

In Barbuda, a major ground wateraquifer has been affected by sand miningactivity. Land and resource use willneed to be managed in the future toensure that this key water resource is notfurther compromised.Finally, although most building supplystores carry water saving toilets,showerheads and faucets, there has beenno national water conservation campaignthat targets households.

New homes should be provided withincentives to install water saving fixturesand old households provided similar


40

incentives to retrofit fixtures in order toconserve water. This would lessen theimpact of drought on households.

Barbuda

Although a large percentage ofhouseholds in Barbuda are withoutmains connection, vulnerability todrought is reduced by extensive natureof ground water resources on the island.

A relatively high water table (3-4 ft. insome parts of Codrington) allowshouseholds to use wells to supplementrain or mains water. However, waterfrom wells is often brackish and theyrisk contamination by virtue of theirlocation relative to septic tanks andsoakways.

Water quality is therefore a critical issueparticularly in periods of drought whencistern water is not available for drinkingand cooking.

The use of a reverse osmosis (RO) plantto ensure a more reliable supply ofpotable water for Barbuda was proposedby APUA in 1996 but rejected byresidents because wastewater from theplant would have been dumped in theCodrington lagoon (J. Mussington, pers.comm..). Desalination remains anoption to be reconsidered in seeking toreduce future vulnerability to drought.Desalting brackish water should be lesscostly than using sea water, while thefurther exploration of ground waterreserves could provide a cost-effectivesource of fresh water for future use.

3.3 Institutional Arrangements

3.3.1 Key Agencies

Institutional capacity to manage droughtis a critical factor in reducingvulnerability to drought events. Keyagencies dealing with drought includeAPUA, the Department of Agriculture,the Livestock Division, Ministry ofPlanning, DCA and the National Officeof Disaster Preparedness (NODS).

The approach to planning, research anddata management with respect todrought is ad hoc. The correctorientation and a commitment to droughtimpact mitigation, including adequateresource allocation and training ofselected staff, are required.

3.3.2 Procedures and Information

It is recognized that drought is arecurring event in Antigua/Barbuda.However, apart from actions being takento reduce problems related to potablewater, there are no clear procedures inplace to mitigate drought impacts anddrought information management isdisorganized.

To improve the capacity for droughtmanagement, drought effects must bedocumented and a database to assist withdecision making is needed. Also,procedures for drought awareness andbuilding of public support for droughtmitigation are critical measures to beconsidered.


41

_________________________________4.0 ANALYSIS OFAREAS AT RISK


42

4.1 Understanding and Applyingthe Concept of Risk

Drought risk for the purposes of thisanalysis is considered as having two (2)contributing factors, namely:

• Recurring environmental ormeteorological events or naturalphysical characteristics beyond thecontrol of man.

• Human practices (policy or land use)that make the population vulnerableto natural events and characteristics.

a) Natural risk factors

• Variable climate (periodic lowrainfall)

• Exposure to wind and marineinfluences

• Exposure to excessive sunlight basedon orientation to sun

• Problem soils, resulting fromgeological history, that may be soilsthat are shallow, stony, erosionprone, have poor infiltration, heavilyleached or lacking in nutrients

b) Land use practices leading tovulnerability

• Removal of forest cover, foragriculture, housing or other needs

• Overgrazing (high density livestockpopulations)

• Cultivation on steep slopes• Disregard for water and soil

conservation practices• High per capita water consumption;

c) Policy

• Subsidized water costs• Government land sales policy and

subsidized infrastructure• Lack of drought insurance• Lack of drought relief programs.

4.2 Areas At Risk to Drought

4.2.1 Drought Risk Criteria forMapping

Mapping of areas on the basis of theirrisk to drought – namely, low, moderate,high, very high – is based on a set ofcriteria. Each criterion is given a valueof one (1) and the total value of an areadetermines its rank:

Low drought risk <4Moderate drought risk 5-6High drought risk 7-8Very high drought risk >9

Drought risk criteria used for mappingare shown in Table 15. A description ofthe criteria follows:

a) Meteorological/Environmental

< 40 inches Rainfall Areas thatexperience < 40 inches of rain annuallyare meteorological disadvantaged notwithstanding the wet periods of the yearwhen soil moisture may be in excess ofplant needs. For most of the year plantscan be expected to experience moisturestress.

Exposure to wind and marineinfluences Areas with excessiveexposure to wind and marine influencesare determined by location, topographyand slope type, using the PGDM basemap with contours. These areas were


43

noted but not mapped in assigningnumerical values for drought riskranking.

Table 15 Drought Risk Criteria

Environmental Meteorological

• Rainfall < 35 inches• Exposure to wind and marine

influences• Shallow soils• Slopes >11°• Cactus scrub vegetation

Hydrological/Infrastructure

• Absence of wells• Absence of agricultural

reservoirs

Human/Landuse

• Crazing• Crop location• Population density > 5,000

per sq. mile

111111

1

1

111

Areas on the east coast of Antigua andBarbuda are relatively more exposed toprevailing winds and hence more proneto wind erosion. Where they occur closeto the sea, salt in atmospheric moistureretard the growth of most plants, exceptthose that have become naturalized oradjusted to such conditions. However,vegetation recovery on cleared orovergrazed slopes then becomes veryslow, irrespective of plant adaptability.When this happens vulnerability todrought increases. East facing convexslopes close to the sea are particularlyprone to wind erosion and desertificationif overgrazed.

Shallow Soils. Shallow soils havelimited moisture retention capacity andare often lacking in nutrients. Rootdevelopment is often retarded because ofpoor soil structure. When such areas loseforest cover by clearing and aresubjected to heavy grazing vegetationrecovery is very slow and in some casesnever occurs. This results in a trend todesertification. For Antigua, areas ofshallow soils coincide with moderate tosteep slopes.

Slopes > 11°. These are in Antigua andnot Barbuda. Where such slopes haveretained forest cover particularly moistforest or dry evergreen woodland, theyare less prone to erosion and better ableto retain moisture than slopes that havelost natural vegetation cover. Habitatdegradation from drought is less severeon slopes in the former category.

Cactus Scrub Vegetation. For Antiguaand Barbuda, the cactus scrubdesignation includes areas that wereformerly cultivated and are nowabandoned to extensive livestockgrazing. The lack of dense vegetationcover in many parts of this vegetationzone encourages grazing and browsingby sheep and goats, major factorscontributing to the vulnerability of thelandscape to drought. Such areasvisually exemplify the brown, harsh andoftentimes depressing conditions ofdroughts.

The Cactus Scrub designation, as usedon the vegetation maps for Antigua andBarbuda, includes remnants ofnaturalized vegetation, which evolved onaccount of meteorological and otherenvironmental influences, along withvegetation in various stages of


44

succession after being cleared orcultivated.

The former may include combinations ofAcacia spp, lucaena and other legumes,agaves, cactus and other xerophiticspecies, all well adjusted to droughtconditions. This type of association isconsiderably less vulnerable to droughtexcept where coverage is sparse enoughto allow overgrazing or browsing of theunder storey. Where this happens, soilerosion or compaction can adverselyaffect soil fertility or otherwise retardplant growth.

Vulnerability is therefore moreassociated with Cactus scrub areas,where vegetative associations are lessadopted to drought conditions or whereland uses create imbalances in thelandscape that may lead to severeerosion, desertification or flooding.

A weakness in using this criterion is thelack of adequate vegetation informationthat would allow a more detailedclassification of the various types ofvegetation associations found within theCactus Scrub designation. Work istherefore needed to update, detail andmore comprehensively map vegetationfor both islands.

Notwithstanding the weakness invegetation data and the drought resistantnature of many plant species found inthe vegetation zone, Cactus Scrub areasremain vulnerable to drought for severalreasons:

• Goats appear to like the generaldryness of this type of landscape andappear to favor a number ofherbaceous plants and other shrubsfound on it.

• Where drought resistant species(example, Acacia spp., Logwood,Black Pearl) are established withsparse vegetative wood cover, over-grazing of under storey vegetationleads to erosion and slower plant re-growth.

• Where grass offers adequate coverfor soil and moisture during normalconditions rapid loss of biomass dueto water deficiencies in the soil andfrom grazing leaves the soil exposed.

• Extensive grazing in Cactus Scrubareas adversely affect plant diversityand the ecology of some areas;species liked by goats and sheephave difficulties surviving, while aninvasive plant such as Neem (toxic togoats) becomes dominant in thelandscape.

• Ornamental plants introduced ingardens falling in this generalvegetation category are often notsuited to local conditions – forexample, water loving plantscultivated in areas with lowprecipitation. Such plants diequickly where water is not availablefor extended periods.

Exposure to Sun – This was alsoconsidered as a criterion but was notused for mapping drought risk because itrequires very site-specific analysis of anarea’s topography, contours andvegetation to determine how these affectthe amount of shade it enjoys duringsunlight.

Concave slopes facing north or southenjoy relatively longer periods of shadeduring the day than east and west facing


45

slopes. This may create slight butcritical temperature differencesamenable to moisture retention,vegetation and crop growth. Thiscriterion can therefore be applied wheredetailed analysis of slope orientation tosunlight and shade is possible.

b) Hydrological/Infrastructure

Absence of wells. These are areas withno wells or known significant groundwater deposits. In the absence of wellsuntapped ground water resources couldbe exploited with hastily drilled wells tooffer relief in extended periods ofdrought. Information to map aquiferswas not obtained. Water productioninformation by wells in variouswatersheds was obtained and used indrought risk ranking for Antigua.

Absence of agricultural reservoirs –areas with no agricultural dams or notenough ponds available to livestockfarmers. Agricultural reservoirs orponds may run dry in an extendeddrought but nevertheless provide acritical source of water for farmers aslong as it is available. Municipal andagricultural reservoirs and ponds aremapped on the watershed data map forAntigua.

c) Human/LandUse

Grazing. Grazing densities of > 6 goatsor sheep per hectare or 1.5 cattle perhectare for pasture areas withoutirrigation are not considered sustainable.It is common knowledge that there areareas in the country that are excessivelygrazed. Although figures on thelivestock populations for Antigua andBarbuda are available, populationdensities by areas are not known.

Where livestock densities are in excessof sustainable limits in improved(managed) pastures, impacts are mostlyfelt within the boundaries of the fencedpasture. Vulnerability from grazing istherefore due mainly to the threats tocrops, gardens and habitats posed by un-tethered livestock found in Mixed Scruband Grazing and Rough Grazingcategories delineated in the land use datamaps for Antigua and Barbuda.

Livestock population and grazingdensity data by area (preferablywatersheds) is required to strengthenvulnerability and impact analysis.

High Population Densities >5,000 persquare mile. St. John’s is the onlysettlement with this level of populationdensity. Vulnerability linked to densityderives mainly from limited space andpoor soil conditions that limit storagecapacity above or below ground.

Households built on small lots in parts ofPoint, Gray’s Green and Ovals areparticularly vulnerable. Such householdsare dependent mainly on piped water(attached to the house or available atstand pipes) and are unable to adequatelystore water when it has to be rationed.

Crops Location. This criterion targetsareas located > 1 mile from mainssupply. This applies to water lovingcrops in the volcanic region of Antiguaas well as crops with lower waterrequirements grown in dryer areas. Thelatter is more drought resistant butvulnerability increases where there is noaccess to water supply mains.

Mango, which constitutes the major treecrop in the country, is less prone to


46

damage from soil water loss than mostperennial crops but is vulnerablenevertheless.Since the information to map watermains could not be acquired, the relativelocation of crops to main and secondaryroads was used to assume their relativedistance from water mains. Waterdistribution information, includingvariations in water pressure along thedistribution network is required toreinforce the use of this criterion and toadjust drought maps as appropriate.

Crops are also vulnerable where theirlocation relative to grazing activity mayrender them susceptible to damage fromlivestock, particularly during drought,when feed material becomes scarce.

Denuded Slopes. Country widemapping of denuded slopes was notpossible during this assessment due totime constraints and therefore thecriterion was not used in drought riskranking. However, some of these areasare included in rough grazing land usedesignation on the land use data map forAntigua.

Such areas should be specificallymapped in the future since they provideready evidence of how poor land usepractices can create vulnerability todrought.

Denuded slopes are areas wherevegetation is almost absent and wheremost of the topsoil has been lost. Theyare indicative of a process, which startedwith the clearing for agriculture orfirewood but have not recovered due to acombination of factors, namely,accelerated erosion, persistent andintense grazing and exposure to windand marine influences.

Such areas exist on the southeast ofAntigua between the Indian Creek areaand Christian Hill. Some of these areas(slopes and associated valleys) areundergoing a process of desertification,which can only be reversed if thecontributing landuse practices arecurtailed. Such practices render theareas vulnerable to meteorologicalagents that hasten land degradation.

4.2.2 Area and Issues for PriorityAttention

a) Areas

The east, north and southeast of Antiguacontain areas of high and very high riskto drought. Environmental and land usefactors comprise to make the region ofthe country the most vulnerable todrought. Within this region, the arearequiring the most urgent attention fallswithin watershed 27-46, one of twowatersheds ranked as being at very highrisk to drought.

The area is at the extreme southeast ofthe island (between English Harbour andSt. James Club). Environmental andhuman (landuse) factors combining tomake this area highly vulnerable todrought include:

• Low rainfall• Shallow soils• Slopes exposed to wind and marine

influences• Overgrazing – the area has one of the

highest goat population

Denuded slopes and narrow valleys inareas forming part of the Nelson’sDockyard National Park provide visual


47

images of a severely degraded landscapeand imminent desertification.

Similar trends are being experienced inother watersheds but perhaps not withthe same degree of devastation. It issuggested that watershed 27-46 beconsidered for undertaking a pilotproject seeking to provide strategies forreducing vulnerability and risk todrought.

The project should include:

• Forest monitoring program,particularly for cactus scrub and dryforest areas subject to threats fromovergrazing. One objective wouldbe to determine carrying capacity forlivestock grazing and livestockpopulation densities that should beallowed.

• Ecosystem studies aimed at betterunderstanding the criticalrelationships between dietaryrequirements of goats and sheep, soiland moisture needs of preferred plantspecies and other ecosystemcharacteristics critical tounderstanding how plants andanimals respond to drought.

• A landscape restoration componentaimed at reversing trends towardsdesertification.

• The development of methodologiesand approaches to involve livestockfarmers in mitigating livestockimpacts.

• The development of policy initiativesto reduce vulnerability and risk todrought.

Successful results of the pilot projectwould be replicated in other parts of thecountry.

In Barbuda, the Palmetto Point, parts ofthe highlands, Codrington lagoon andthe northern section of the island withSalinas, lagoons and mangroves areconsidered of low to moderate risk todrought. Most of the remaininglowlands are considered of high risk. Nopart of the island was categorized in thevery high drought risk category.

b) Major issues

While the pilot project is being used totest approaches for mitigating theimpacts of drought, actions should beconsidered and implemented to addressother issues, including:

• Overgrazing. This is perhaps thesingly most critical factorcontributing to the country’svulnerability to drought. Trends invegetation, habitat and landscapedegradation, key factors contributingto the country’s vulnerability todrought, will not be reversed untilovergrazing is controlled.

• Meteorological data. A nationwidenetwork of meteorological stations isneeded collect data and monitorrainfall, evapo-transpiration, relativehumidity, etc., to improve thecountry’s database for informedanalysis and decision-making.

• Vegetation classification andmapping. Existing vegetation data isinadequate for drought management.A vegetation classification andmapping project should beundertaken to improve the capacityrequired for managing variousvegetation zones against droughtimpacts. Classification shouldinclude a description of soil and


48

moisture requirements of key plantspecies within each vegetation class.

• Agricultural water storageinfrastructure. The mapped dataindicate an imbalance in thedistribution of agricultural storagereservoirs and ponds. Vulnerabilityto droughts could be reduced forlivestock and some crops byinvestment in additional reservoirand pond capacity in selectedwatersheds.

• Potable water. Water rationing byAPUA in February and March, 2001,indicates that desalinated water (62%of the total water production of 4.5million cu.m/yr) has reduced but noteliminated vulnerability in respect ofpotable water supply. Since rainfalldoes not affect water production bydesalination, rationing is necessarybecause of limitations or constrainsin the supply of ground and surfacewater, which account for 33% oftotal production. Additional waterproduction capacity and/or storageare required if vulnerability is to bereduced in the future. This will bemore so if significant growth occursin the hotel and commercial sector,which now accounts for 17.5% ofcurrent water consumption. Thesame will be true if major growthoccurs in domestic waterconsumption, which currentlyaccounts for 30% of current totalconsumption.


49

_____________________________5.0 DROUGHTMAPPING


50

5.1 Data Collection and Sources

Data for drought hazard mapping wereobtained from:

• Past projects and project reports,e.g. the OAS Natural ResourcesAssessment, Application andProjects for the Agricultural Sectorof Antigua/Barbuda.

• Government agencies, such as theCoolidge Met Office, Ministry ofPlanning and the DevelopmentControl Authority (DCA). In thelatter case, maps from the DraftNational Physical Development Planwere used.

• Field observations.

Relevant sources are credited onindividual maps.

5.2 Structure and Content of Maps

The drought hazard maps for Antiguaand Barbuda were produced byanalyzing ArcView GIS generated datamaps with the following titles:

• Mean Rainfall Isohyets (Antigua)• Vegetation (Antigua and Barbuda)• Slope (Antigua and Barbuda)• Watersheds (Antigua and Barbuda)• Soils (Antigua and Barbuda)• Land Use (Antigua and Barbuda)

The structure (content) of the each dataset is given in Appendix 5.

5.3 Analysis of Data

Data was analyzed using ArcView. TheRisk Criteria, identified in Section 4.0,

were used as vulnerability themes andspatially manipulated by:

(i) Analyzing the spatial occurrenceof vulnerability themes in thevarious watershed units. Thiswas used to rank Antigua’swatersheds in relation to droughtrisk based on numerical scoresgiven in Appendix 6 (a). Asimilar system was used forBarbuda despite the fact that notall watershed boundaries arefully defined. Numerical scoresfor Barbuda’s watersheds aregiven in Appendix 6 (b).Acreage data for land covered byrelevant themes, e.g. grazing wasnot calculated but could be donein the future when vegetation andother data are updated;

(ii) Overlaying (intersecting, asopposed to merging in ArcViewGIS terminology) the themes todetermine areas of critical risk.

In relation to ( i), watersheds were givendrought risk ranks as shown in Table 16for Antigua and Table 17 for Barbuda.

By overlaying themes from data sets,critical areas within the watersheds thatrequire remedial policy and landmanagement actions can be identified.

Table 16 Drought Risk Ranking ofAntigua Watersheds

Level of Risk Watersheds

Low 1, 2, 3Moderate 4-11, 12-20, 21-26,High 47-53, 54-62, 63-66,

78-84, 85-86Very High 27-46, 67-77


51

Table 17 Drought Risk Ranking ofBarbuda Watersheds

Level of Risk WatershedsLow I, XModerate V, VI, VII, VIIIHigh II, III, IV, IXVery High --

5.4 Map Use and Limitations

a) Map Use

The maps can be used for sector,strategic or development planning,disaster mitigation planning and droughtmanagement. The watershed, as ahydrological unit, with a commondrainage basin is considered the mostappropriate physical space for managingdrought even though precipitation levelsmay vary within its boundaries.

Hence, the ranking of watersheds inrelation to drought risk provides thenecessary background for furtherinvestigation and mitigation of droughtimpacts.

For any given watershed, themes fromdata sets (maps) can be over-laid ormerged to highlight actual or potentialimpacts from drought, as shown in thefollowing examples:

a) Overlay: Cactus Scrub vegetation+ Rough Grazing and MixedScrub/Rough Grazing.

Result: Tells the extent to which grazingimpacts on this vegetation zone. Areasthat fall outside of where the two themesintersect are often characterized bydense Acacia and other woody or thornyspecies, dense enough to discourageforaging by goats and sheep.

Mitigation strategies to protect suchareas, which may be the least degradedof the Cactus Scrub associations, willrequire updating field data for moreaccurate mapping and/or detailedreclassification of the Cactus Scrubvegetation zone.

b) Overlay. Grazing + > 11 degreeslopes + exposed slopes (east-coast, Antigua) + < 40 inchesrainfall. Result: Indicates areas ofactual or potential landscapedegradation, where vegetation re-growth is retarded; also indicatesactual and potential areas of soilerosion from wind and rain;

c) Merge. Agriculture (crops) +rough grazing & mixedscrub/rough grazing. Result:actual or potential threats to cropsfrom livestock.

Limitations in Use of Maps

The maps can be used as references todrought mitigation planning and droughtimpact assessment. Data inadequaciesshould however determine the extent towhich maps can be used to makedecisions without additional researchand field observations.

Attention should be given to weaknessesin various maps, namely:

• Mean Rainfall Isohyets (Antigua).There are not enough rainfall stationsin Antigua and Barbuda to generateaccurate lines of equal rainfall(isohyets). The map for Antigua wasadopted from sources that did notindicate how many rainfall stationswere used in producing the isohyets.A rainfall map was not produced for


52

Barbuda because the data was notavailable. An adequate number ofrainfall stations for both islands needto be installed and data collected ona regular basis.

• Vegetation (Antigua andBarbuda). No detailed and up-to-date maps produced from vegetationstudies are available for either island.The vegetation maps are producedusing different land use mappingsources and very limited fieldobservation. Vegetation maps basedon thorough field investigations andan agreed classification system iscritical to drought mitigation.

• Slope (Antigua and Barbuda). Theslope maps provide general ratherthan detailed slope categorization.Detailed slope analysis can begenerated by GIS from the PGDMcontour map. This should be donewhere site specific assessment ofdrought impact and mitigation isrequired.

• Watersheds (Antigua andBarbuda). Watershed boundarieswere verified by study of a DOScontour map for Antigua and arebelieved to be accurate for Barbuda.The boundaries of critical aquiferswere not mapped because theinformation was not obtained. Thisshould be plotted as the informationis obtained and where possible aninvestigation made of the effects ofland uses in watersheds on aquiferrecharge.

• Soils (Antigua and Barbuda). Thesoil classification used for bothislands is general but adequate for

this assessment. More detailed soilmaps have been digitized for anotherstudy in the PGDM project and canbe used for specific area analysis.

• Land Use (Antigua and Barbuda).Land use for Antigua was updated bythe DCA (1999), after the OAS(1992), and adopted with slightmodifications for the Antigua landuse data map. The Barbuda map wasupdated from the OAS, 1992. Landuse is however undergoingcontinuous change in Antigua andshould be updated as significantchanges are observed, particularlywhere practices could lead toincreased vulnerability to drought.


53

_________________________________ 6.0 INDICATORS FORFUTUREIDENTIFICATIONOF DROUGHTS


54

This section summarizes and describesindicators that suggest approaching oractual drought conditions. Theseindicators are discussed under thefollowing categories:

• Meteorological/Environmental• Hydrological• Agricultural• Socio-economic

a) Environmental Indicators

• Reduction in biomass production ofcommon grass species. Earlywarning is wilting, as grass rootsbecome progressively damaged bylack of soil water. Grass coverbecomes patchier as fallen leafdebris is blown away by wind inexposed areas. Homeowners find noneed to use lawn mowers.

• Leaf fall and litter in Forests. TheForestry Division uses the increasein leaf fall and litter (detritus) on theforest floor as one indicator ofdrought. No measurement of volumeof weight is done. Since leaf fallvaries between species, measurementwould need to be correlated withplant associations.

In Cactus Scrub forests, xerophytes(plants growing in dry areas) withsmall hard leaves can decrease waterloss when the area begins to get drierand will drop their leaves inprolonged drought.

• Damage to “indicator” plantspecies. The Ficus, planted as hedgeor trees, normally stays green; itssmall and shiny leaves limit moistureloss and its wide spreading root

system allows it to seek moisture andnutrients beyond its drip line. Whenthe Ficus loses a lot of its leaves it isan indication that the country is in aperiod of prolonged drought.

Some types of xerophytes, (succulents,such as cacti and agaves) utilize storedwater in dry periods without noticeabledamage. In fact, such plants can survivefor weeks when uprooted, so that signsof damage (dried leaves or brokenstems) may be an indication of negativewater balance resulted from extendeddrought.

b) Hydrological

Reduction in Ground Water levels. TheAPUA Water Division uses groundwater levels at various well fields as anindicator of hydrological drought.

The approximate average water levels ofselected well fields in Antigua areprovided in Table 18. The table alsogives the approximate levels for eachfield that is indicative of droughtconditions.

There is a time lag betweenmeteorological and agricultural droughtconditions and hydrological drought asindicated by ground water levels. Thelatter occurs later but the time lag cannotbe accurately predicted in the absence ofrainfall data that could be correlated withrates of pumping and recharge, for thewatersheds in which the well fieldsoccur.

Recovery from meteorological andagriculture droughts occurs in advanceof the replenishment of ground water toaverage levels. Again, the data does not


55

exist to accurately predict the gap intime between these events.

Table 18 Drought Indicator Levels atWell Fields, Antigua

Well Ave. Level Drought Level (ft. below grade)

_________________________________

Bendals 40 60Cades Bay 25-3 45-50Claremont/Old Road 25-30 45-50Collins/Bristol 15-25 25-45Follies 50-60 70-80The Valley 30-40 50-60_________________________________(Source: V. Yearwood, Water Division,APUA)

Water level figures given by APUA areapproximations. This leaves room formore precision in measuring water levelsas they recede as the basis for makingdecisions on water rationing.

Reduction of Water Levels at MunicipalReservoirs. Receding water levels atmunicipal reservoirs is another droughtindicator used by APUA. However, itwas not determined if specific indicatorlevels for the various municipalreservoirs were established. Indicatorlevels at selected reservoirs could bedetermined over a period of time bywidening the scope of monitoring tomeasure consistently meteorological andhydrological data, including, rainfall,temperature, wind speed, evaporationand seepage.

Water Rationing. APUA begins toration water before ground water levelsrecede to critical points. In fact, the

decision to begin rationing water appearsto be influenced by perceivedmeteorological and agricultural droughtconditions.

Reduction of Water Levels atAgricultural Reservoirs. This is anotherindicator observed but not measured byauthorities.

c) Agricultural

Livestock

Livestock gain water from drinkingwater, foraging plants and watermolecules produced in the breakdown offood. They lose water through urine,feces and water evaporated through skinand lungs.

Some livestock can reabsorb water intheir intestines to produce dryer fecesand can reduce water used to excretenitrogenous wastes of the urine (Brewer,1994).

As animals well adapted to droughtconditions goats are presumed to usesimilar physiological measures toconserve water. Despite this, they andother livestock will show signs of stressduring extended drought:

• Weight loss. Symptoms are reducedmuscle density, visible ribs. Effectsare more associated with tetheredlivestock. However, untetheredanimals foraging larger areas forfood use more energy and may suffersimilar weight loss.

• Higher incidence of disease.

• Unusual high incidence ofmiscarriage among pregnant females.


56

Crops

Indicators may include:

• Negative water balance as evidencedfrom wilting and ultimately death ofplants in extended droughts.

• Unusually high incidence ofdiseases, as plants are unable toobtain needed moisture and nutrientsfrom the soil.

d) Socio-economic

Socio-economic indicators includechanges in water use practices byhouseholds and businesses:

• Storage of water in existing ortemporary storage facilities as aresult of water rationing.

• Reduction of water used forlandscaping of household and hotelgardens.

• Regular trucking of water to meetwater deficit due to rationing.

• Higher incidence of respiratoryailments due to excessive dust in avery dry landscape. Respiratoryailments related to drought are notrecorded for Antigua and Barbudabut are generally considered adrought related health impact.


57

References

Brewer. Richard. 1994. The Science ofEcology. Second Edition.

Cadogan, Paul. Dr. 2000. Quoted inarticle, Extreme Weather DistressesRegional Farmers. Caribbean Edition,Executive Time, page 13.

Hill, I.D, Lang, D.M, Vernon, K.C.1966. Soil and Land Use SurveysAntigua and Barbuda. RegionalResearch Centre, Imperial College ofTropical Agriculture, University of theWest Indies, Trinidad.

Ivor Jackson & Associates. 2000.Environmental Audit/Assessment, JollyHarbour, Antigua

Island Resources Foundation (IRF).1991. Antigua and BarbudaEnvironmental Profile

Ministry of Trade and Planning,Government of Antigua. 1997. CaseStudy of Climate Change Impacts andAdaptation Assessments in Antigua andBarbuda. Water Resources Sector.Jerry Fernandez et al, Study TeamParticipants.

National Drought Mitigation Center.1995. Categories of DroughtDefinitions.

OAS. 1991. Desertification HazardAssessment (Chapter 9).

OAS, Department of RegionalDevelopment and Environment. 1992.Natural Resources AssessmentApplication, and Projects for the

Agricultural Sector of Antigua andBarbuda. Report and Maps

Weir, Collin, C. 1980. Caribbean Soils.


58

______________________________ APPENDICES


59

Appendix 1 Tasks Outlined in Termsof Reference

Under this contract, the consultant willundertake the following activities forAntigua, Barbuda:

a) Meet with the relevant agencies andindividuals to collect reports anddata on drought hazards. These areto include both agencies that collectinformation on drought and thoserepresenting sectors affected bydrought (e.g., tourism, agriculture,water authorities, economic andphysical planning. Documentcurrent information and proceduresregarding drought, existingdefinitions of drought, designatedlead agencies and existing policiesand plans.

b) Undertake a drought hazardvulnerability assessment for Antiguaand Barbuda. The assessment is tobe consistent with current droughthazard assessment methodologiesand with reporting needs forAntigua/Barbuda under theConvention to CombatDesertification. Activities under thehazard assessment include:

i) Compile historic evidence ofdrought effects on criticalsectors. To the extentpossible, the social,economic and environmentalimpacts of these events areto be described. From thisinformation, develop aworking definition ofdrought and indicators forfuture identification of futuredrought events.

ii) Compile information on andassess causes of drought.

Included in this investigationare the contributions ofprecipitation patterns,controlled and uncontrolledgrazing, soil types anddevelopment.

iii) Identify the sectors most atrisk to the effects of drought.Assess the vulnerability ofthese sectors to drought anddetermine the level ofpreparedness for futureevents. Meet withrepresentatives of thesesectors to determineappropriate responses to anygaps in preparedness.

iv) Produce island-widegeographic informationsystem (GIS) data layersdepicting drought hazard riskzones in Antigua/Barbuda.These data are to be in anArc/Info or ArcView-compatible format, geo-referenced to the commonmapping standard for theislands, and accompanied byappropriate GIS metadata.

v) Using the GIS data describedabove, produce island-widedrought hazard maps forAntigua and Barbuda. Thesemaps will depict areas ofhigh, medium and low-riskto drought. All maps are toinclude a common set ofreference features (e.g,roads, settlement areas), tobe provided by the PDGMfor this purpose, and willconform to the PDGMhazard map layout, asdefined by GS/OAS. Whereappropriate, information on


60

vulnerable sectors is to beincluded on these maps.

c) Produce a technical report of thedrought hazard assessment. Thisreport should include a proposeddefinition of drought in the contextof the islands and indicators forfuture identification of droughtevents. This technical report shouldalso identify key contacts on eachisland for drought hazards.

d) Produce non-technical summaries ofthe drought hazard assessment. Thissummary should be suitable fordistribution independent of thetechnical summary and should beapproximately 2500 words in length.


61

Appendix 2 Average Yearly Rainfall,Recorded at the Meteorological Office,V.C. Bird International Airport(Antigua), 1960 – 2000

Year Rainfall Year Rainfall_________________________________

1960 33.12 1981 57.121961 32.97 1982 43.241962 48.38 1983 22.311964 33.65 1984 45.861965 36.37 1985 46.641966 27.52 1986 35.121967 29.14 1987 56.231968 25.09 1988 51.821969 49.79 1989 43.321970 64.72 1990 40.461971 41.19 1991 30.491972 38.83 1992 47.221973 25.98 1993 39.701974 52.33 1994 30.471975 36.49 1995 50.271976 36.78 1996 36.041977 38.44 1997 26.461978 49.29 1998 49.871979 67.29 1999 62.011980 32.15 2000 30.96

Ave 40.95_____________________________(Source: Met Office, 2001)

Appendix 3 Antigua Annual Rainfall,1950 – 1990 (Inches)

Year Rainfall Year Rainfall________________________________

1950 50.05 1971 45.181951 60.79 1972 45.921952 56.78 1973 27.731953 29.15 1974 50.701954 41.58 1975 37.781955 46.89 1976 40.891956 49.42 1977 38.501957 43.79 1978 49.001958 47.35 1979 66.001959 41.55 1980 33.001960 40.76 1981 58.001961 40.58 1982 40.001962 50.91 1983 22.261963 44.06 1984 33.251964 34.46 1985 ----1965 31.69 1986 35.121966 29.74 1987 56.231967 34.58 1988 51.821968 27.19 1989 43.321969 52.05 1990 21.73*1970 61.23________________________________*8 months(Source: IRF, 1991, after APUA)


63

Appendix 4 Population Density, Antigua and Barbuda, 1991

Parish Area Population Density(sq. miles) (persons/sq. mile)

_________________________________________________________________

St. John’s 28.5 35,635 1,250- St. John’s City 2.9 21,514 7,419- St. John’s Rural 25.6 14,121 552

St. George’s 9.3 4,473 484St. Peter’s 12.8 3,622 284St. Phillip’s 17.0 2,964 174St. Paul’s 18.5 6,117 331St. Mary’s 22.8 5,303 241

Antigua 108.0 58,114 538Barbuda 62.0 1,241 20________________________________________________________________(Source: Development Control Authority, as taken from Population and Housing Census, 1991)


64

Appendix 5 Structure (Content) of Mapped Data Sets, Antigua and Barbuda

Data Set Map Title Content (Legend)

AntiguaAntigua Mean Annual RainfallIsohyets (inches)

Rainfall isohyets

Antigua Vegetation Cactus Scrub; Dry woodland; Moist Forest/Dry Woodland; Mangrove Woodland/swampAntigua Slope Classes 0-2, 3-11, 11-20 and 21-30 degree slopesAntigua Watersheds Watershed boundaries; Watershed numbers; Agricultural reservoirs; Municipal reservoirs; PondsAntigua Soils Deep/alluvial/ colluvial; Deep kaolinitic clay; Shallow soils; Complex of shallow and deep soilsAntigua Land Use Agriculture; Citronella grass; Improved pasture; Mixed scrub and rough grazing; Rough grazing;

Woodland; Urban settlement; Settlement; Swamp/mangrove; Tourism; Recreational/Historicarea; Industrial; Airport; Military uses; Freshwater; Salt pond

BarbudaBarbuda Vegetation Woodland (limestone area); Cactus scrub; Mangrove; Salina vegetationBarbuda Slope Classes 0-2, 2-5, 5-10, 10-20 degree slopesBarbuda Watersheds Watershed boundaries; Watershed numbersBarbuda Soils Codrington Clay; Barbuda clay loam; Blackmere clay loam; Beach sand; Mangrove/swamp;

SalinaBarbuda Land Use Food crops; Coconut plantation; improved pasture; Mixed Scrub and rough grazing; Settlement;

Tourism; Airstrip; Industrial area


65

Appendix 6(a) Drought Risk Totals by Watersheds, Antigua

WatershedsCriteria 1 2 3 4-11 12-20 21-26 27-46 47-53 54-62 63-66 67-77 78-84 85-86

Cactus scrub vegetation 1 1 1 1 1 1 1 1 1 1 1 1 1> 11 degree slopes 0 1 1 1 1 0 1 1 0 0 1 1 0Shallow soils 0 0 0 1 1 1 1 1 1 1 1 1 1Grazing 1 1 1 1 0 0 1 1 1 1 1 1 1Rainfall < 40 inches/yr 1 0 0 0 0 0 1 1 1 1 1 0 0Pop. Density >5000persons/sq mile

0 0 0 0 0 0 0 0 0 0 1 0 0

Crops (agriculture) 1 1 1 1 1 1 1 1 1 1 1 1 1Absence of wells 0 0 1 0 0 1 1 1 1 1 1 1 1Absence of agriculturalreservoirs

0 0 0 1 1 1 1 0 1 1 1 1 1

Exposure to winds andmarine influences

0 0 0 0 0 1 1 1 1 1 1 1 1

Total 4 3 4 6 5 6 9 7 8 8 10 8 7


66

Appendix 6(b) Drought Risk Totals by Watersheds, Barbuda

WatershedsCriteria I II III IV V VI VII VIII IX X

Cactus scrub vegetation 1 1 1 0 0 0 0 0 1 0> 11 degree slopes 0 0 0 0 0 0 0 0 0 0Shallow soils 0 1 1 1 1 1 1 1 1 1Grazing 1 1 1 1 0 0 0 0 1 0Rainfall < 40 inches/yr 1 1 1 1 1 1 1 1 1 1Pop. Density >5000persons/sq mile

0 0 0 0 0 0 0 0 0 0

Crops (agriculture) 0 1 1 1 0 0 0 0 1 0Absence of wells 0 0 1 1 1 1 1 1 0 1Absence of agriculturalreservoirs

1 1 1 1 1 1 1 1 1 1

Exposure to winds andmarine influences

0 0 0 0 1 1 1 1 0 0

Total 4 6 7 6 5 5 5 5 6 4

Notes:Watersheds IV and VIII have relatively small areas of cactus scrub compared to overall acreage, hence the scores.There are two very small areas of >11° slopes in watersheds II and III that were ignored in scoring.No wells were mapped for watershed I but the assigned score is due to the presence of an important aquifer.


67

Appendix 7 Map References, from Antigua and Barbuda Country Environmental Profile, IRF, 1991

Title Page______________________________________________________________________

1. Mean Average Rainfall (Long average isohyets) for Various Locationsin Antigua 11

2. Antigua/Slope Classes 143. Soil Map of Antigua (from Atkins Land and Water Management, 1983) 164. Watersheds of Antigua 625. Watersheds of Barbuda 636. Several Large Agricultural and Municipal Reservoirs for the Island of Antigua 657. Potential Biodiversity Protection Sites for the Island of Antigua 788. Potential Biodiversity Protection sites for the Island of Barbuda 789. Antigua Land Use Prepared by the Planning Office 1977 13710. Antigua Parks and Protected Areas (Existing and Proposed) 15111. Barbuda Parks and Protected Areas (Existing and Proposed) 15212. Antigua Terrestrial Life Zones 15513. Location of GOAB and CARDI Agricultural Facilities in Antigua 187


68

Appendix 8 List of Contacts

1. Mr. McRonnie Henry, Forestry Division, Ministry of Agriculture2. Dr. Robinson, Chief Vetenary Officer, Livestock Division, Ministry of Agriculture3. Mrs. Cheryl Kanyuira, Livestock Division4. Ms. Veronica Yearwood, Antigua Public Utilities Authority (APUA)5. Mr. Patrick Jeremiah, Head, Antigua/Barbuda Met Office6. Mr. Keithly Meade, Climatologist, Antigua/Barbuda Met Office,7. Dr. Debra Thomas, Development Control Authority8. Mr. Jerry Fernandez, Ministry of Planning9. Mr. Ernest Benjamin, Ministry of Planning10. Mrs. Cynthia Simon, Antigua Hotel and Tourist Association11. Mr. Rob Sherman, Chairman, Antigua Hotel and Tourist Association12. Mr. Clarence Johnson, Siboney Beach Hotel13. Mr. Arthur Edmond, Antigua Village14. Mr. John Mussington, Barbuda

Drought Hazard Assessment and Mapping for Antigua and Barbuda · Drought Hazard Assessment and Mapping for Antigua and Barbuda Post-Georges Disaster Mitigation Project in Antigua

Documents