THE GAMBIA

GEOGRAPHY, POPULATION AND WATER RESOURCES

The Gambia is the smallest country on the African continent, with an area of 11 300 km2, of which about 20% is considered as wetland. The cultivable land area is estimated at about 430 000 ha, which is 38% of the total area. The cultivated area was 195 543 ha in 1991, or 45% of the cultivable area and 17% of the total area.

TABLE 1

Basic statistics and population

Area of the country

Cultivable land

Cultivated land

1994

1992

1991

1 130 000

430 000

195 543

ha

ha

ha

Total population

Population density

Rural population

1994

1994

1993

1 081 000

96

75

inhab.

inhab./km2

%

Water supply coverage

Urban population

Rural population

1992

1992

97

50

%

%

The total population is about 1 million (1994), of which about 75% is rural. The average population density is 96/km2, but ranges from 40 to more than 130/km2 (excluding Banjul, the capital). The Gambia has one of the highest population growth rates in the world: 4.1% per year.

Agriculture accounts for 25% of GDP and employs 60% of the house-holds.

Climate and water resources

The country lies in the Sahelian agro-climatic zone and has a long dry season between November and May. Average daily temperature is 30°C in the dry season and 27°C in the wet season. The average annual rainfall is 961 mm. There has been a steady decline in rainfall from 1875 onwards, which still continues and which is causing increased salinity in the lowlands and increased aridity in the uplands.

The country is almost completely included in the basin of River Gambia, which discharges 8 km3 yearly into the ocean. At the border with Senegal, the river has an annual discharge estimated at about 5 km3. Because of the flat topography there is a pronounced marine influence: in the dry season the salt tongue moves as far as 250 km upstream. The seasonality and salinity have important repercussions on land use.

In 1982, water withdrawal was 0.020 km3 (Figure 1). Of this, 0.018 km3 was agricultural water withdrawal, but this figure probably covers only the full or partial control irrigation schemes (1 670 ha).

TABLE 2

Water balance

Water resources:

Average precipitation

Internal renewable water resources – total

Internal renewable water resources – per caput

Global renewable water resources

Dependency ratio

Total dam capacity

De-salinated water

1994

961

10.9

3

2 775

8

62.5

-

-

mm/yr

km3/yr

km3/yr

m3/yr

km3/yr

%

km3

106 m3/yr

Water withdrawal:

- Agricultural

- Domestic

- Industrial

Total

per caput

as a % of internal renewable water resources

Other withdrawal

1982

1982

1982

18.2

1.4

0.4

20

29

0.7

-

106 m3/yr

106 m3/yr

106 m3/yr

106 m3/yr

m3/yr

%

106 m3/yr

Wastewater:

Produced

Treated

Re-used treated wastewater

-

-

-

106 m3/yr

106 m3/yr

106 m3/yr

TABLE 3

Irrigation and drainage

Irrigation potential

1984

80 000

ha

Irrigation:

1. Full or partial control irrigation: equipped area

- surface irrigation

- sprinkler irrigation

- micro-irrigation

% of area irrigated from groundwater

% of area irrigated from surface water

% of equipped area actually irrigated

2. Spate irrigation area

3. Equipped wetland and inland valley bottoms

4. Other cultivated wetland and inland valley bottoms

5. Flood recession cropping area

Total water managed area (1+2+3+4+5)

- as a % of cultivated area

- increase over last 10 years

- power irrigated area as % of water managed area

1991

1991

1991

1991

1991

1991

1991

1991

1 670

1 670

0

0

-

-

65

-

-

13 170

-

14 840

7.6

-

-

ha

ha

ha

ha

%

%

%

ha

ha

ha

ha

ha

%

%

%

Full or partial control schemes: Criteria

Large schemes > - ha

Medium schemes

Small schemes < - ha

Total number of households in irrigation

-

-

-

-

ha

ha

ha

Irrigated Crops:

Total irrigated grain production

as a % of total grain production

Harvested crops under irrigation

- rice

1991

1991

1991

1991

18 254

19.6

11 277

11 277

t

%

ha

ha

Drainage - Environment:

Drained area

as a % of cultivated area

Flood-protected area

Area salinized by irrigation

-

-

-

-

ha

%

ha

ha

Undisplayed Graphic

Water withdrawal (total: 0.02 km3 in 1982)

Undisplayed Graphic

Area (ha) of harvested irrigated and rainfed crops (1991)

Undisplayed Graphic

Distribution of the water managed areas (1991)

IRRIGATION DEVELOPMENT

The area harvested annually is about 180 000 ha, or some 40% of the country's cultivable land. The major crops grown are groundnut, millet, sorghum, maize and rice. Minor crops include cotton and vegetables (Figure 2). Nearly all of it is rainfed. Only about 1 500 ha is under pump irrigation, although rice is also grown on some additional 10 000 to 15 000 ha of mangrove swamps and freshwater swamps (Figure 3). In the mangrove area, rice is grown from August to January by constructing simple protection dikes.

To avoid an increase in salinity, the safe limit for irrigation from the river Gambia, without major dam construction, was estimated to be a maximum of 2 400 ha in the dry season. The lower and lower central river sections (up to Carrol's Wharf) contain considerable areas of actual and potential acid sulphate soils.

INSTITUTIONAL ENVIRONMENT

Policy guidance and technical support for agriculture is provided by the Ministry of Agriculture (MOA) through a Central Management Unit and four main Departments.

The Department of Agricultural Services (DAS) is responsible for Agricultural Extension Services, the Soil and Water Management Unit (SWMU), the Crop Protection Service, the Food and Nutrition Unit, and the Agricultural Communications Unit. SWMU is in charge of developing policies on soil and water management, land capability zoning, upland conservation and development of small-scale water control schemes in lowland rice ecologies. It is divided into five sections, of which the Engineering Section is involved in irrigation development.

The Department of Water Resources (DWR) of the Ministry of Natural Resources and Environment (MNR&E) liaises closely with SWMU.

TRENDS IN WATER RESOURCES MANAGEMENT

Rice is traditionally cultivated, primarily in the lowlands, as a subsistence crop. As a consequence of rapid population growth, demand greatly exceeds local production and the country is currently importing large quantities of rice to meet its domestic requirements.

National policies give high priority to increased rice production using technologies which are environmentally sound and sustainable without subsidies. Government also gives high priority to food security and poverty alleviation within the context of sustainable development.

According to a recent IFAD and FAO Investment Centre mission, rice could be produced in a competitive way if it focuses on the appropriate ecology and adopts a simple and sustainable technology. It proposed a 20-year Lowlands Agricultural Development Programme (LADEP) covering traditional rice ecologies throughout The Gambia.

MAIN SOURCES OF INFORMATION

Central Statistics Department, Ministry of Finance and Economic Affairs. 1993. Statistical Abstract of The Gambia 1992.

Department of Planning, Ministry of Agriculture. 1991. Statistical Yearbook of Gambian Agriculture 1990.

FAO. 1982. The Gambia: Water Resources Development in the Framework of the National Food Plan. Report prepared by P. Pallas and S. N'Guiamba for FAO Technical Cooperation Programme project TCP/GAM/0104. Rome.

FAO. 1984. Agricultural Research in The Gambia River Basin. Rome.

FAO. 1994. The Gambia: Lowlands Agricultural Development Programme. FAO Investment Centre/IFAD Cooperation Programme report Nº 52/94 IFAD-GAM 15. Rome.