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General summary Africa
The 53 African countries have been grouped into seven regions based on geographical and climatic homogeneity, which has a direct influence on irrigation. These regions (Figure 5) and the countries they include are:
- Northern: Algeria, Egypt, Libya, Morocco, Tunisia;
- Sudano-Sahelian: Burkina Faso, Cape Verde, Chad, Djibouti, Eritrea, Gambia, Mali, Mauritania, Niger, Senegal, Somalia, Sudan;
- Gulf of Guinea: Benin, Côte d’Ivoire, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Sierra Leone, Togo;
- Central: Angola, Cameroon, Central African Republic, Congo, Democratic Republic of the Congo, Equatorial Guinea, Gabon, Sao Tome and Principe;
- Eastern: Burundi, Ethiopia, Kenya, Rwanda, Uganda, United Republic of Tanzania;
- Southern: Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia, Zimbabwe;
- Indian Ocean Islands: Comoros, Madagascar, Mauritius, Seychelles.
They are identical to the regions in the previous report "Irrigation in Africa in figures" (FAO, 1995), which allows comparison with the earlier data. This general summary presents distinguishing features arising from the new data collected on a national scale for issues addressed in the country profiles. The interest of this new survey lies both in the updating of data and in the trends in the last ten years.
The country profiles are either in English (E) or in French (F), depending on the official FAO language of the country.
PRESENTATION OF THE STUDY
Ten years after the first publication on Africa, it appeared necessary to update the data and to identify the main changes in water use and irrigation that had occurred on the African continent. To the two objectives of the previous publications a third was added in this new survey of the 53 countries in Africa:
- to provide for every country the most accurate status of rural water resources management, with a special focus on irrigation, by featuring major characteristics, trends, constraints and prospective changes on irrigation and
on water resources;
- to support continental and regional analyses by providing systematic, up-to-date and reliable information on the status of water resources and of agricultural water management that can serve as a tool for regional planning
and predictive studies;
- to prepare a series of chronological data in order to highlight the major changes that have occurred in the last decade on national, regional and continental scales.
To obtain the most reliable information possible, the survey was organized as follows:
- Overview of the bibliography and of the existing information at country level.
- Collection of information by country using a detailed questionnaire filled in by national consultants, international consultants, or the AQUASTAT team at FAO.
- Compilation and critical analysis of the information collected using dataprocessing software developed for this specific survey, and selection of the most reliable information.
- Preparation of country profiles and submission to national authorities responsible for water resources or water management for verification, correction and approval.
- Preparation of the final profile, the tables and the figures presenting the information by country.
- Updating the on-line database.
- Preparation of the general regional analysis, the figures and the regional tables.
Where possible, AQUASTAT made use of national capacity and competence. While collecting the information by country, preference was given to national consultants as they have a better knowledge of their own country and easier access to national documents. The choice of the countries for which a national consultant was recruited depended on several factors, namely: the importance of irrigation in the country; the availability of an expert; the scarcity of data observed during the previous survey; and the funds available. For about half of the countries concerned, a national consultant assisted the AQUASTAT team.
Country profiles were prepared in the FAO official language of each country (except Equatorial Guinea, which was prepared in French), and they are presented in this language, as are the related tables and figures. Only the regional general summary and its illustrations (figures and summary tables) are presented in both English and French.
They describe the state of water resources and water use in the respective country, as well as the state of agricultural water management. The aims are to describe the particularities of each country and the problems met in the development of the water resources and, in particular, irrigation. They summarize the irrigation trends in the
country and the perspectives for water management in agriculture as described in the literature. The country profiles have been standardized and organized in sections according to the following model:
- geography, climate and population;
- economy, agriculture and food security;
- water resources and water use;
- irrigation and drainage development;
- water management, policies and legislation related to water use in agriculture;
- environment and health;
- perspectives for agricultural water management;
- references and additional information.
Standardized tables were used for each country. A hyphen (-) indicates that no information was available. As most information is available only for a limited number of years, the tables present the most recent reliable information and indicate the year to which it refers.
Data collection, processing and reliability
The main sources of information were:
- national policies, and water resources and irrigation master plans;
- national reports, yearbooks and statistics;
- reports from FAO and other projects;
- international surveys;
- results and publications from national and international research centres;
- the Internet.
Furthermore, the following sources systematically provide certain data:
- FAOSTAT. This is the only source used for variables of area (total, arable and permanent crops) and population (total, rural, urban, female, male, en economically active). FAOSTAT data are provided every year by the countries through the FAO representation.
- World Development Indicators. This database is the World Bank's premier annual compilation of data on development. This source provides the data on gross domestic product (GDP) and the contribution of agriculture to the GDP.
- The Joint Monitoring Programme (JMP) for water supply and sanitation. This is a joint programme of the World Health Organization (WHO) and the United Nations Chrildre's Fund (UNICEF), providing data on access to improved water sources.
- The United Nations Development Programme (UNDP). This provides the data on the Human Development Index (HDI).
In total, more than 50 variables were selected and these are presented in the national tables attached to the country profiles. They are ordered in categories corresponding to the various sections of the country profiles: characteristics of the country and population; water: resources and use; and irrigation and drainage. A detailed description of each variable is given below. Additional tables were added to the country profiles where information was available, especially in order to specify regional or river basin data.
In most cases, a critical analysis of the information was required in order to ensure the general coherence of information collected for a given country. Where several sources resulted in divergent or contradictory information, preference was given to information collected at the country or provincial levels rather than at regional or world levels. Moreover, except in the case of evident errors, official sources were privileged. As regards shared water resources, the comparison of information between countries made it possible to verify and complete the data concerning the flows of transboundary rivers and to ensure coherence at a river basin level.
In spite of these precautions, the accuracy, reliability and frequency with which information is collected vary considerably according to the region, the country and the category of information. These considerations are discussed in the country profiles.
On a continental scale, data for certain variables (cultivable area, irrigation techniques, origin of water for irrigation, and irrigated crops) were too incomplete to allow a regional analysis. Indeed, for several countries, it was difficult, even impossible, to obtain new data. At the end of the 1980s and at the beginning of the 1990s, many
African countries had prepared water resources and irrigation master plans, which facilitated data gathering during the previous survey. However, few of these countries have updated their data since then. Estimations based on the field knowledge of the AQUASTAT team and the Land and Water Division of FAO were then used to complete the regional analysis, especially those sections concerning cultivable area, irrigation techniques and origin of water. Thus, it is not always possible to explain the differences between the two AQUASTAT surveys.
Data concerning areas under water management may have undergone significant changes in the last ten years because of re-adjustments to equipped or non-equipped areas that are no longer cultivated. Indeed, available information about irrigated areas and areas under water management is more reliable than in the previous survey. This is because of the availability of the previous reference, which allowed comparison with new data. Thus, conclusions about the evolution of irrigation methods can reflect current trends on the ground and/or better knowledge of the variables involved.
The regional analysis tables show the period 1994-2004 as the period between the two surveys. The AQUASTAT team justifies this choice by virtue of the slow evolution of data for different years for each country. However, should more precision be required, the summary tables and the on-line database specify the exact year for the items of national data.
GEOGRAPHY, CLIMATE AND POPULATION
The total area of Africa is 30 million km2, or 22 percent of the world’s emerged landmass. The five largest countries (Sudan, Algeria, Democratic Republic of Congo, Libyan Arab Jamahiriya, and Chad in decreasing order) represent 34 percent of this territory, while the smallest five countries (all islands: Cape Verde, Comoros, Mauritius, Sao Tome and Principe, and Seychelles) constitute little more than 3 percent (Table 1 and Table 22). The cultivated area is estimated at 211 million ha, or 27 percent of the cultivable land on the continent. The Sudano-Sahelian Region is the region with the greatest potential in terms of cultivable land, but only 19 percent of this is exploited compared with more than 40 percent in the Northern, Gulf of Guinea and Indian Ocean Islands Regions (Table 1).
The climate in Africa is influenced by the equator, by the two tropics, and by the two large deserts (the Sahara in the Northern Hemisphere, and the Kalahari in the Southern Hemisphere). Very different climates are in juxtaposition, ranging from very dry to wet equatorial by way of more moderate climate (Figure 6).
Africa’s population was estimated at 868 million inhabitants in 2004, representing about 14 percent of the world’s population (Table 2 and Table 32). Nigeria, situated in the Gulf of Guinea, is the most populous country with 15 percent of the African population (Table 23 and Figure 1). The average proportion of the population living in rural areas (61 percent) exceeds the world average (51 percent). However, this average lies between the extremes of the Northern Region (48 percent) and the Eastern Region (76 percent). The average population density of 29 inhabitants/km2 also hides wide diversity at the national and regional levels (Figure 7). The five most densely populated countries are Mauritius, Comoros, Rwanda, Burundi and Seychelles, with 604, 354, 322, 254 and 182 inhabitants/km2, respectively (Table 23). On a continental scale, the Gulf of Guinea Region has the highest populations density (93 inhabitants/km2), while the Sudano-Sahelian Region is on the whole not very densely populated (13 inhabitants/km2). In 2000, 300 million Africans, or more than one-quarter of the total population, had no access to drinking-water. In the same year, average life expectancy was 41 years.
The Northern Region, consisting of Algeria, Egypt, Libyan Arab Jamahiriya, Morocco and Tunisia, covers an area of about 6 million km2, or 19 percent of the continent (Table 1). Algeria covers 40 percent of the area of this region (Table 22). Each of the countries in this region has access to the Mediterranean Sea. Out of a total cultivable area of 65 million ha, only 28 million ha are cultivated, or 43 percent of the potential.
This region is bordered in the north by the Mediterranean Sea and in the south by the Sahara, both of which have a strong influence on the climate (more moderate in the north and very dry in the south). Annual average precipitation in the region reaches only 96 mm (western Sahara excluded), ranging from 750 mm in the extreme northwest of Morocco to close to 0 mm in the south of Egypt.
In 2004, the Northern Region had 153 million inhabitants, with 48 percent of the population living in rural areas (Table 2). Half of this population lives in Egypt (Table 23). The average regional density of 26 inhabitants/km2 is equal to the average density of the continent, but the population is concentrated mainly on the Mediterranean Sea coasts and in the Nile Delta and Nile Valley, where density can reach 1 165 inhabitants/km2, while the desert is practically uninhabited. The overall annual population growth of 1.9 percent in the period 1994-2004 was relatively low, ranging from 1.2 percent in Tunisia to 2.2 percent in the Libyan Arab Jamahiriya, and it has decreased compared with the previous decade (2.5 percent between 1984 and 1994).
This region covers 12 countries: Burkina Faso, Cape Verde, Chad, Djibouti, Eritrea, Gambia, Mali, Mauritania, Niger, Senegal, Somalia and Sudan. It has a total area of 8.6 million km2, or 28 percent of the continent (Table 1). The Sudan, the largest country on the continent, represents 29 percent of this territory (Table 22). Four of the countries are landlocked: Burkina Faso, Chad, Mali and Niger. In 2000, the cultivable area was 208 million ha (50 percent of which were in Sudan) and crops were cultivated on about 39 million ha, or almost 19 percent of the cultivable area.
This region extends to the north of the Sahara and is bordered in the south by the Gulf of Guinea Region, which is more humid. The climate is generally dry, of Sahelian or Sudano-Sahelian type, and characterized by two seasons. The annual average precipitation is 311 mm, ranging from 25 mm in the north of the Sudan to more than 1 600 mm in the south of this country. The average evapotranspiration is about 2 000 mm/year, but it can reach 8 000 mm/year in the Gash-Barka Basin in Eritrea.
About 113 million people lived in the region in 2004, which is equal to a density of 13 inhabitants/km2, the lowest on the continent (Table 2). However, national average densities range from 3 inhabitants/km2 in Mauritania to 129 inhabitants/km2 in the Gambia (Table 23). About 66 percent of this population is rural. However, 84 percent of the population of Djibouti is concentrated in urban areas, in particular in the capital. The regional annual population growth of 3.2 percent in the period 1994-2004 was the highest on the continent and approximately the same as in the period 1984-1994 (almost 3.3 percent/year).
Gulf of Guinea Region
Nine countries form this region: Benin, Côte d’Ivoire, Ghana, Guinea, Guinea-Bissau, Liberia, Nigeria, Sierra Leone and Togo. They cover a total area of 2.1 million km2, or 7 percent of the continent, with Nigeria accounting for 44 percent of this area (Table 1 and Table 22). Of the total cultivable area of 120 million ha, about 55 million ha were cultivated in 2002 (46 percent of the potential).
The region is bordered in the north by the Sudano-Sahelian Region and in the south by the Atlantic Ocean. The climate is Sudanese in the north and wet tropical in the south. The annual average precipitation of the region is 1 356 mm, with large variations between countries: from 1 039 mm/year in Benin to 2 526 mm/year in Sierra Leone. Evapotranspiration increases from 1 500 mm/year in the south of Togo to 5 200 mm/year in the north of Nigeria.
The population was 196 million inhabitants in 2004, of whom 65 percent lived in Nigeria (Table 2). The average density of 93 inhabitants/km2 is the highest on the continent. However, variations both between and within countries can be very important, ranging from 31 inhabitants/km2 in Liberia to 138 inhabitants/km2 in Nigeria, and from 16 inhabitants/km2 in Beyla in the province of Guinea Forestiere in Guinea to 2 429 inhabitants/km2 in its capital, Conakry (Table 23). In this region, about 54 percent of the population is rural. Annual population growth ranges from barely 1.7 percent in Ghana to 2.9 percent in Guinea-Bissau, with a regional average of 2.8 percent in the period 1994-2004, compared with 3.4 percent between 1984 and 1994.
This region comprises eight countries: Angola, Cameroon, Central African Republic, Congo, Democratic Republic of the Congo, Equatorial Guinea, Gabon, and Sao Tome and Principe. Its total area is 5.3 million km2, or 18 percent of the continent (Table 1). The estimated cultivated area in 2002 was about 21 million ha, or 12 percent of the 173 million ha of cultivable land (Table 22).
The Central African Republic is the only landlocked country in the region. The climate varies from tropical dry or wet to equatorial, depending on countries. Average precipitation (1 425 mm/year) reaches both extremes in Sao Tome and Principe, ranging from 900 mm/year in the northeast to 6 000 mm/year in the southwest. On a regional scale, the averages range from 1 010 mm/year in Angola to 3 200 mm/year in Sao Tome and Principe. Evapotranspiration in this region varies from 1 200 mm/year to 2 200 mm/year.
The Central Region has an estimated population of 94.5 million inhabitants (11 percent of the African population). Some 56 percent of them live in the Democratic Republic of the Congo, which is also the largest country (44 percent of the area of the region). The low average population density of 18 inhabitants/km2 ranges from 5 inhabitants/km2 in Gabon to 172 inhabitants/km2 in Sao Tome and Principe (Table 2 and Table 23). Annual population growth ranges from 1.5 percent in the Central African Republic to 3.3 percent in the Democratic Republic of the Congo, for a regional average of 2.7 percent between 1994 and 2004, significantly lower than in the previous period (3.6 percent).
The Eastern Region comprises six countries: Burundi, Ethiopia, Kenya, Rwanda, Uganda, and United Republic of Tanzania. Its total area is about 3 million km2, or 10 percent of Africa (Table 1). Ethiopia and the United Republic of Tanzania constitute 70 percent of the territory of this region (Table 22). Burundi, Ethiopia, Rwanda and Uganda are landlocked. The cultivated area is 37 percent of the total cultivable area of 83 million ha.
The Eastern Region is bordered in the northwest, north and northeast by the Sudano-Sahelian Region, in the east by the Indian Ocean, in the south by the Southern Region, and in the west by the Central Region. Thus, the climate is diversified. It is dry in parts of Ethiopia and Kenya, equatorial in Uganda, tropical in the west of Burundi in the Imbo Plain near Lake Tanganyika, and moderate tropical in the highlands of Rwanda and the United Republic of Tanzania. Distributed over one or two periods, the average annual precipitation is 920 mm, ranging from less than 100 mm in the northeast of Ethiopia to 3 000 mm in some areas of the United Republic of Tanzania.
The population of the region is 185 million inhabitants, or 21 percent of the African population (Table 2). The average population density is 63 inhabitants/km2, ranging from 40 inhabitants/km2 in the United Republic of Tanzania to 322 inhabitants/km2 in Rwanda (Table 23). The annual population growth of this region was 2.9 percent in the period 1994-2004, but, depending on countries, it has varied between 1.8 and 3 percent/year in the last few years.
The Southern Region comprises nine countries: Botswana, Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Zambia and Zimbabwe. The region has a total area of 4.7 million km2, or 16 percent of the continent (Table 1). South Africa, Namibia and Mozambique together represent more than 60 percent of the total area (Table 22). The cropped area is about 33 million ha, or 29 percent of the total cultivable area of 114 million ha.
The region is bordered in the northwest by the Central Region, in the northeast by the Eastern Region, and in the west, south and east by the Atlantic and Indian Oceans, which meet at the Cape of Good Hope. Mozambique, Namibia, and South Africa have access to the sea, the other countries are landlocked. The main landscapes of the region are: the fringing plains; the Kalahari scrub-desert with a total surface area of about 500 000 km2 (covering a wide part of Botswana and extending towards Namibia and South Africa); and Africa’s Great Rift. The climate is dry in the deserts, moderate at higher altitudes (Lesotho), and tropical to subtropical in the rest of the region. Rains fall mainly in the summer (October-April), except near the Cape of Good Hope in South Africa, where the climate is Mediterranean and rain falls in winter. The annual average precipitation in the region is 659 mm, ranging from less than 100 mm in the desert to more than 2 000 mm in the north of Mozambique. The most humid country is Malawi (with an average precipitation of 1 181 mm/year), and the least humid is Namibia (285 mm/year). Evapotranspiration can exceed 3 700 mm/year in certain zones of Namibia.
The region has a total population of 107 million inhabitants, of whom 57 percent live in rural areas (Table 2). The average population density is rather low (23 inhabitants/km2), ranging from 2.4 inhabitants/km2 in Namibia to 104 inhabitants/km2 in Malawi (Table 23). Population growth is also limited at no more than 2 percent/year in all the countries. In the last two decades, population growth has declined from 2.8 percent/year in the period 1984-1994 to 1.7 percent/year in the period 1994-2004. This decline is a consequence of the very high incidence of HIV/AIDS (infection rates ranged from 12.2 percent in Mozambique to 38.8 percent in Swaziland at the end of 2003 among all people aged 15-49 years), which has also caused a severe reduction in the average life expectancy in the region, from 48 years in 1970 to 38 years in 2003 (Table 23).
Indian Ocean Islands Region
Madagascar represents more than 99 percent of the 591 760 km2 of this region, which also includes Comoros, Mauritius and Seychelles (Table 1 and Table 22). The cultivated area of 3.8 million ha, a very significant proportion of which is in Madagascar, covers 46 percent of the cultivable area (8.3 million ha).
In Madagascar, the climate varies from semi-arid to tropical humid, while it is generally tropical humid in Seychelles and the Comoros, and subtropical to temperate maritime in Mauritius. The mean annual rainfall is 1 510 mm, ranging from 900 mm in the Comoros to 2 040 mm in Mauritius.
The total population of the four countries amounts to 20 million inhabitants, with 90 percent in Madagascar (Table 2 and Table 23). The average population density is rather low (34 inhabitants/km2), but there are wide difference between Madagascar (30 inhabitants/km2) and the other three countries (446 inhabitants/km2 on average). The population growth of the region declined from 3.2 percent/year in the period 1984-1994 to 3 percent/year in the period 1994-2004. However, there are considerable differences between the countries as Seychelles has the lowest national population growth rate of the whole continent (1 percent/year) and the Comoros one of the highest (2.9 percent/year).
ECONOMY, AGRICULTURE AND FOOD SECURITY
Poverty is common and sometimes extreme in Africa. Thirty-four of the 49 least developed countries (LDCs) are African and 315 million people, or 36 percent of the total population, survive on less than US$1/day. The sum of national GDPs in 2003 amounted to US$641 000 million, or barely 5 percent of the GDP of the United States of America. It corresponds on average to a GDP of US$738/inhabitant, ranging from US$91/inhabitant in Ethiopia to US$8 890/inhabitant in Seychelles. The HDI (range = 0-1) varies from 0.273 in Sierra Leone to 0.853 in Seychelles (35th out of a total of 177 countries), while the 19 countries with the lowest HDI are African. The HDI for Liberia and Somalia is not known.
In 2003, the added value of the primary sector (agriculture) contributed 2.5 percent to the GDP in Botswana and 60.8 percent in the Central African Republic, with an average for the whole of Africa of 17.7 percent. More than half of the economically active people are engaged in the farming sector (Table 2). The Northern (28 percent), Gulf of Guinea (40 percent) and Southern Regions (46 percent) are exceptions. The more developed Northern Region has less agriculture and more industries and services. Nigeria, a large oil-exporting country, has a large impact on the data of the Gulf of Guinea Region. Finally, South Africa (where development is very marked), Namibia and Botswana, three countries where apartheid was formerly practised, are responsible for this reduced percentage of active agricultural workers. At a country level, Burundi and Rwanda, where 90 percent of the total labour force is engaged in the primary sector, are the two countries with the most limited cultivable area per inhabitant on the continent (less than 0.2 ha/person). Conversely, Namibia and Gabon, with the largest cultivable area per person (12.4 and 11.2 ha/person, respectively), have less than 40 percent of their economically active people working in the primary sector. With 5 percent of the economically active people engaged in agriculture and cultivating about 23 ha per active agricultural worker, the Libyan Arab Jamahiriya is the country that allocates the lowest percentage of economically active people to this sector.
The HIV/AIDS pandemic (Table 23) has reached such a scale that it influences the economy of those countries most affected. About two-thirds (64 percent) of all the people infected by AIDS live in sub-Saharan Africa (SSA), as well as more than three-quarters (76 percent) of all the women who have acquired this disease. The incidence of the disease in the SSA region was almost 7.4 percent at the end of 2004. The Northern Region has an incidence of less than 0.3 percent for people aged 15-49 years, and Mozambique with an incidence of 12.2 percent is the least affected country in the Southern Region. Four countries in the Southern Region have an incidence rate of 20-30 percent: Namibia, South Africa, Zimbabwe and Lesotho, in increasing order. In Botswana and Swaziland, the incidence is even higher at 37.3 and 38.8 percent, respectively. The other regions fall between these two extremes: The national-level incidence ranges from 0.6 to 4.8 percent in the Sudano-Sahelian Region, from 1 to 7 percent in the Gulf of Guinea Region, from 4.1 to 8.8 percent in the Eastern Region, and from 3.9 to 13.5 percent in the Central Region. In the Indian Ocean Islands Region, only the incidence for Madagascar is known (1.7 percent).
This disease causes a significant increase in rural poverty and malnutrition, two plagues already widespread in Africa. It aggravates difficulties for rural women; the rates of infection can be 3-5 times higher for women than for men. Finally, the disease exerts a negative impact on household food security as well as on the national food production because of the loss of agricultural workers, notably in countries where agriculture contributes considerably to GDP. Indeed, the largest number of infected people is in the 15-49 year age bracket, the most productive group in the population. Therefore, the population composition has been modified, leading to a situation where old and young people predominate. When a family member is affected, the family not only has to compensate for the loss in income but also has to take care of the patient.
In 2004, FAO estimated that in the 25 most affected countries in Africa, about 7 million agricultural workers had been victims of AIDS since 1985; another 16 million could become victims before 2020. The most affected African countries could lose up to 26 percent of their labour force in the next two decades. Average life expectancy in SSA is now 47 years, while it would have been 62 years without AIDS. In Botswana, life expectancy at birth has fallen to its 1950 level, but Zimbabwe has seen the most dramatic drop with life expectancy falling from 55 years in 1970 to 33 years in 2003.
Renewable water resources
Annual precipitation in Africa is estimated at about 20 360 km3, a continentwide average of 678 mm (Figure 6). Disparities between countries and regions are very important. The driest country is Egypt with 51 mm/year on average, followed closely by the Libyan Arab Jamahiriya (56 mm/year) and Algeria (89 mm/year), which suggests that Morocco (346 mm/year) and Tunisia (207 mm/year) are most advantaged countries in the Northern Region (Table 24). This region is the driest region on the continent with an average of 96 mm/year. The countries with precipitation exceeding 2 000 mm/year (Sao Tome and Principe with 3 200 mm/year, Sierra Leone 2 526 mm/year, Seychelles 2 330 mm/year, Liberia 2 390 mm/year, Equatorial Guinea 2 156 mm/year, Mauritius 2 041 mm/year) belong to the Gulf of Guinea, Central and Indian Ocean Islands Regions, which are the rainiest (Table 3). With more than 7 500 km3/year, the Central Region receives 37 percent of all precipitation in Africa in an area that accounts for less than 20 percent of the total. In contrast, the Northern Region, with an area similar to the Central Region, receives less than 3 percent of total precipitation.
Renewable water resources for the whole of Africa amount to about 3 930 km3, or less than 9 percent of global renewable resources (Figure 8 and Table 32). The Central Region is the best endowed, with 48 percent of Africa’s resources for only 18 percent of its area (Figure 2). With 24 percent of Africa’s resources, the Gulf of Guinea Region is also well supplied with water. On the other hand, the Northern Region is the most disadvantaged with less than 1 percent of the renewable water resources for an area equivalent to 19 percent of Africa. The Democratic Republic of the Congo has 900 km3 of internal renewable water resources, 23 percent of the total for African, while the Libyan Arab Jamahiriya has only 0.01 percent of these resources.
There has been a decrease in internal renewable water resources per inhabitant since the previous AQUASTAT survey. In 2004, the average was 4 530 m3/inhabitant, ranging from 325 m3/inhabitant in the Northern Region to 19 845 m3/inhabitant in the Central Region. At country level, the values range from 25 m3/inhabitant for Egypt to 121 392 m3/inhabitant for Gabon (Table 24). However, the distribution of total renewable water resources is different because of international and interregional river basins, with values ranging from 106 m3/inhabitant in the Libyan Arab Jamahiriya to 217 915 m3/inhabitant in Congo. Indeed, because of an agreement with the Sudan, Egypt benefits from very important outside contributions (of the Nile River). Congo also benefits from water resources from the Congo River from countries situated upstream, unlike the Libyan Arab Jamahiriya and Gabon, which do not have any external resources. Therefore, the dependency ratio, which enables the proportion of total renewable resources originating from outside a country to be quantified and, thereby, a country’s dependence on external water resources, is negligible for these two countries (Table 24).
Table 4 presents total and internal renewable water resources for seven countries where resources per inhabitant are very limited. With respect to internal renewable water resources, seven countries have resources lower than the cutoff point of 500 m3/inhabitant a year, while Algeria and Djibouti exceeded this threshold slightly in 1994. Taking into consideration international rivers shared with countries upstream, Egypt, Mauritania and Niger (thanks to the Nile, Senegal and Niger rivers, respectively) are well above this threshold in terms of total renewable water resources. Only Algeria, Djibouti, Libyan Arab Jamahiriya and Tunisia remain below this threshold, not benefiting (dependency ratio of zero for Djibouti and Libyan Arab Jamahiriya) or benefiting only slightly (ratio lower than 10 percent for Algeria and Tunisia) from outside contributions. It is necessary to highlight the particular case of Egypt, which, thanks to the Nile River, saw its total resources rise to almost 800 m3/inhabitant in 2004 from 25 m3/inhabitant of internal resources. Therefore, its dependency ratio is very high (97 percent), but a large part of this contribution (55.5 km3 or 98 percent) is secured by a treaty with the Sudan, located upstream on the Nile River.
The main international river basins are, in decreasing order of area: Congo (Zaire), Nile, Lake Chad, Niger, Zambezi, Orange, Senegal, Limpopo, and Volta. These nine basins cover nearly half of the total area of the continent (Table 5 and Figure 9).
The water in these river basins, shared between several countries, is managed through basin organizations that group together all or some of the countries included in one basin. Of the basins mentioned, only the Congo River Basin does not have this type of organization to coordinate actions related to the water resources of the nine states contained in this basin, although it is the largest African river basin. The organizations managing the other basins are:
- The Nile Basin Initiative (NBI), created in 1999 on the initiative of the Council of Ministers of water resources of the countries of the Nile Basin (Nile COM), furthers a first agreement in 1959 between Egypt and Sudan on the water of the river, and also of the Committee of Technical Cooperation for the Promotion of the Development and the Environmental Protection of the Nile Basin (TECCONILE) in 1993. Among the ten countries included in the Nile Basin (Burundi, Democratic Republic of the Congo, Egypt, Eritrea, Ethiopia, Kenya, Rwanda, Sudan, Uganda and United Republic of Tanzania), only Eritrea is not a member of the NBI, but it is a "prospective member". It participates in the Nile COM dialogue as an observer. The initiative tries to realize sustainable socio-economic development through the use of water resources in the Nile Basin and equitable benefit sharing. Therefore, the main objectives are: (i) to develop the Nile River water resources in an equitable and sustainable manner in order to ensure prosperity, security and peace for the inhabitants; (ii) to guarantee effective water management and optimal resource use; (iii) to promote cooperation and combined action between member countries; and (iv) to combat poverty and promote economic integration.
- The Lake Chad Basin Commission (LCBC) was created in May 1964 by the leaders of the states that share Lake Chad (Cameroon, Chad, Niger and Nigeria). The Central African Republic became the fifth member in 1994. Algeria and Sudan, also included in the lake basin, are not part of the "conventional basin". The main objectives of the LCBC are: (i) to conserve the limited water resources; (ii) to restore the water level in Lake Chad, which is one of the largest wet zones in Africa; (iii) to combat desertification through dune fixation; (iv) to combat erosion and to lead programmes of plant regeneration; and (v) to collect data on the resources for an effective management of the river basin.
- The Niger Basin Authority (NBA), created in 1980, is the successor to the Niger River Commission, created in 1964. Of the ten countries included in the basin (Algeria, Benin, Burkina Faso, Cameroon, Chad, Côte d’Ivoire, Guinea, Mali, Niger and Nigeria), only Algeria is not part of the NBA. The objective of the NBA is: "to promote cooperation between member countries and to ensure an integrated development of the resources of the river basin, notably in energy, water, agriculture, livestock, fishing, aquaculture, forestry, wood, transport and communication, and industry". To achieve this, it is necessary to accomplish the following three objectives: (i) harmonize and coordinate the national policies on the development of the resources in the basin; (ii) plan river basin development by developing and implementing an "integrated river basin development plan"; and (iii) conceive, develop, undertake and maintain common works and projects.
- The Zambezi Watercourse Commission (ZAMCOM) was created in 2004 by the eight countries of the Zambezi Basin: Angola, Botswana, Malawi, Mozambique, Namibia, United Republic of Tanzania, Zambia and Zimbabwe. Negotiations for the creation of this basin organization started in the 1980s, but were interrupted at the beginning of the 1990s to allow discussions on the Protocol on Shared Watercourse Systems of the Southern African Development Community (SADC), signed in 1995. The objective of ZAMCOM is to promote the fair and reasonable use of the Zambezi water resources, as well as their effective management and sustainable development. The governments of Zambia and Zimbabwe work together in the Zambezi River Authority (ZRA) to co-manage the river, concentrating in particular on managing the Kariba Dam, located on the Zambezi River and forming the border between the two countries.
- The International Commission for the Orange Senqu River (ORASECOM) was created in 2000 by the four states that share the basin: Botswana, Lesotho, Namibia and South Africa. It is responsible for studying the potential of the basin’s resources. At the same time, it is necessary to strengthen human and institutional capacities in order to facilitate the integrated and effective management of the water resources, thereby enabling the sustainable development of all of the basin countries.
- The Organization for the Development of the Senegal River (OMVS), created in 1972, comprises Mali, Mauritania and Senegal. Although Guinea shares the basin’s waters, it is not a member of the OMVS, having withdrawn from the previous organization (Organisation des États riverains du Sénégal in 1968). The OMVS has taken over from previous organizations, namely: Mission d’études et d’aménagement du fleuve Sénégal, created in 1934; Mission d’aménagement du fleuve Sénégal, created in 1938 and which became a common body of water resources development for the three autonomous states in 1959; Inter-State Committee, created in 1963 and which also included Guinea; and Organisation des États riverains du Sénégal, created in 1968. The mission of the OMVS is: (i) to achieve food self-sufficiency for the population of the basin and of the subregion; (ii) to secure and improve incomes for population in the river valley; (iii) to preserve the balance of the ecosystems in the subregion and in particular in the basin; (iv) to reduce the vulnerability of the economies of the member states to climate hazards and negative external factors; and (v) to accelerate the economic development of the member states.
- In 2002, the four countries located in the Limpopo River Basin (Botswana, Mozambique, South Africa and Zimbabwe) set up the Limpopo Basin Permanent Technical Committee (LBPTC), which replaced the Permanent Technical Committee of the Limpopo Basin.
- An agency does not yet exist for the Volta River Basin, but its creation seems imminent. Among the six countries of the basin (Benin, Burkina Faso, Côte d’Ivoire, Ghana, Mali and Togo), Ghana and Burkina Faso have already strengthened their dialogue for the management of their shared water resources related to the Project for Improving Water Governance in the Volta River Basin, launched in July 2004. The Volta Basin Technical Committee (VBTC) brings together experts from ministries in charge of water for the six countries that share the Volta River Basin. It held its first session in March 2005, enabling the adoption of internal regulations and the election of the VBTC officials whose mission is to work on the establishment of a Volta River Basin agency.
The total dam capacity in Africa is 798 km3, of which 726 km3 relates to the capacity of 53 large dams built in 22 river basins (Table 25). On the nine international river basins indicated in Table 5, 31 large dams have been built with a total capacity of 643 km3. The Southern Region contains more than one-third of the total dam capacity on the continent (39 percent), followed by the Gulf of Guinea Region (29 percent) and the Northern Region (24 percent), while the Central Region and the Indian Ocean Islands Region, the most humid on the continent, have a small dam capacity (Table 6). Five main dams (situated in the three regions with the highest capacity on the continent) total 565 km3 of capacity, or 71 percent of the total capacity in Africa (Table 7). The dam with the largest capacity is the Kariba Dam (188 km3). More than half of the dams are in the Southern Region. This probably reflects the fact that the inventory of dams in South Africa is very exact because it includes even small-capacity dams.
Non-conventional sources of water
Data on non-conventional sources of water are only available for 15 countries. These countries are in particular those whose renewable resources are limited and who already use a very considerable portion of their water. Table 8 shows that they belong mainly to the Northern Region and, at a much lower level of use, to the Southern Region. The reuse of treated wastewater and water desalination take place mainly in dry countries seeking to increase their limited resources. The main countries practising desalination are: Egypt, South Africa, Libyan Arab Jamahiriya, Algeria, Tunisia, Morocco, Mauritania, Cape Verde, Seychelles, Sudan and Djibouti, in decreasing order of production. Some countries have also introduced irrigation projects that use treated wastewater, mainly in urban and peri-urban agriculture.
The absence of data on the quantity of wastewater produced and/or treated in the Gulf of Guinea, Central and Eastern Regions reflects a lack of sanitation and wastewater treatment systems or their inefficiency in many countries in these regions.
The data on water withdrawal refer to the gross quantity of water withdrawn annually for a given use. Table 9 presents the distribution of water withdrawal by region for the three large water-consuming sectors: agriculture (irrigation and livestock watering), water supply (domestic/municipal use), and industry. Although able to mobilize a significant portion of water, requirements for energy purposes (hydroelectricity), navigation, fishing, mining, environment and leisure activities have a low rate of net water consumption. For this reason, they are not included in the calculation of the regional withdrawals but they do appear in the country profiles where information is available.
For most countries, the methods used for the calculation or the measurements for obtaining the values of the withdrawals are not specified. For the countries for which recent data were not available or were not reliable, the withdrawal estimations calculated by AQUASTAT for 2000 have been used.
The annual total water withdrawal for Africa is 215 km3, or barely 5.5 percent of the renewable water resources on the continent (Table 9) and less than 6 percent of world withdrawals (Table 32). On a continental scale, 86 percent of inventoried withdrawals are used for agriculture, a value higher than the global agricultural water withdrawal (70 percent). However, this figure varies substantially at regional level. The Sudano-Sahelian and the Indian Ocean Islands Regions have the highest levels of agricultural withdrawals (95 and 94 percent, respectively, of the total regional water withdrawal), while the Central Region uses only 56 percent of its withdrawals for agriculture. The annual precipitation in this region allows rainfed agriculture, which is not feasible in the dry countries. Generally speaking, as in 1995, these are the countries that withdraw the highest volumes of water. Indeed, about 70 percent of Africa’s total water withdrawal is concentrated in the Northern and the Sudano-Sahelian Regions. These two regions cover nearly half of the continent (48 percent) and account for two-thirds of the irrigated areas (67 percent).
The regional-level values are influenced strongly by some countries: Egypt accounts for 73 percent of the withdrawals in the Northern Region; Sudan accounts for 67 percent in the Sudano-Sahelian Region; Cameroon accounts for 49 percent in the Central Region; Ethiopia and United Republic of Tanzania account equally for 76 percent in the Eastern Region; Nigeria accounts for 65 percent in the Gulf of Guinea Region; and South Africa accounts for 58 percent in the Southern Region (Table 26). Although they cover only 27 percent of the continent, these seven countries account for 64 percent of African water withdrawals. However, they are also home to 47 percent of its population and 67 percent of its irrigated areas.
Water withdrawals per inhabitant are 247 m3/year, but this average conceals significant variations both between and within regions. They range from 21 m3/inhabitant/year in the Central Region (with 6 m3/inhabitant/year in the Central African Republic and 7 m3/inhabitant/year in the Democratic Republic of the Congo) to 786 m3/inhabitant/year in the Indian Ocean Islands Region (Figure 10). The region whose rate of water withdrawal (as a function of internal renewable water resources) is the lowest is the Central Region (0.1 percent), while the region with the highest rate of water withdrawal is the Northern Region (200 percent) (Figure 11). This latter rate is induced by the contribution and the use of water resources from outside the region (water from the Nile River in Egypt), and to a lesser extent by the use of non-renewable water resources (in Algeria and Libyan Arab Jamahiriya).
Domestic water withdrawal per inhabitant is low at 25 m3/year for the continent as a whole, with rather small regional and national variations compared with agricultural water withdrawals (from 7 m3/inhabitant/year in the Central Region to 58 m3/inhabitant/year in the Northern Region). Somalians use the least water for domestic purposes (less than 1.5 m3/inhabitant/year), while annual domestic consumption in Mauritius exceeds 173 m3/inhabitant (reflecting the impact of the tourism industry).
Table 10 presents the irrigation potential by river basin. Because of this distribution by basin, water resources shared by several countries, notably international rivers, are counted only once. The irrigation potential generally takes into account at the same time the land suitable for irrigation and the renewable water resources. However, estimation methods vary and different estimations are sometimes available for the same country depending on the factors considered (resources, techniques, economic criteria, the environment, etc.).
The irrigation potential of the continent is estimated at more than 42.5 million ha, considering irrigation potential by basin and renewable water resources (Figure 12). One-third of this potential is concentrated in two very humid countries: Angola and the Democratic Republic of the Congo. For two countries, the irrigation potential is less than the area under water management (see below). In Algeria, the area managed is 112 percent of the potential while in the Libyan Arab Jamahiriya it is 1 175 percent of the irrigation potential (Table 28). These countries also use non-renewable fossil groundwater for irrigation, whereas Figure 12 considers only renewable water resources. They are also among the countries that have developed non-conventional sources of water.
IRRIGATION AND WATER MANAGED AREAS
Typology of irrigation and water management
Initially, irrigation in Africa was associated with irrigation plains of large perennial rivers, such as the Niger, Senegal, Nile, Volta, Zambezi, etc. where governments developed the first large irrigation schemes. Since the end of the 1980s, the irrigation sector has undergone important changes, such as liberalization of the production chain, the transfer of scheme management to users, and the emergence of environmental concerns. Furthermore, donor interest in this sector has waned for a number of reasons, such as the decline in world food prices, the high per-hectare development cost (which moreover increases because the easiest areas to develop for irrigation have already been developed), investments necessary for rehabilitation, and environmental standards (which discourage the construction of dams). There is a tendency to promote small irrigation projects (sometimes with private-sector investment) and user participation on the basis of the better results obtained. At the same time, the use of pumps (powered by animals, humans or motors) has enabled groundwater use to become more widespread. This has given rise to a new environmental problem: the overexploitation of aquifers and its numerous consequences (seawater intrusion, sustainability, etc.).
Depending on the regions, irrigation is seen as a necessary technique without which agricultural production would be practically impossible in dry countries, or as a means to increase productivity and cropping intensity, and to favour crop diversity in the most humid countries; hence, the large variety of techniques developed for water management.
Table 11 presents the regional distribution of the areas under water management, making a distinction between areas under irrigation (the sum of full/partial control irrigation areas, spate irrigation areas, and equipped lowlands) and the other cultivated lowland areas that are non-equipped (wetlands, inland valley bottoms, and flood recession cropping areas). The total area where water other than direct rainfall is used for agricultural production has been named "area under water management". The term "irrigation" refers to areas equipped to supply water to crops (Table 27 and Table 28). The distinction between irrigation and water management is sometimes difficult; in particular, the demarcation between equipped and non-equipped areas is often vague, given that equipment in Africa often consists of small devices for holding water, but which do not always allow full water management.
The areas under water management cover more than 15.4 million ha in Africa, but their geographical distribution is very uneven both from region to region and from country to country (Figure 13). More than 40 percent of the water managed area is concentrated in the Northern Region and the percentage increases further when considering only those areas under irrigation. Egypt accounts for 54 percent of the irrigated area in the Northern Region. The Sudano-Sahelian Region ranks second with 19 percent of the water managed area and 20 percent of the irrigated area. However, these figures reflect the area equipped for irrigation in the Sudan (71 percent of the area equipped for irrigation in the region and 63 percent of the area under water management). Finally, the Southern Region contains 15 percent of the area equipped for irrigation and the water managed area on the continent. South Africa has a strong effect on the figures for this region as it accounts for 73 percent of its irrigation.
Spate irrigation is typical of dry countries. It is used mainly in the Northern Region (Tunisia, Morocco and Algeria) and in the Sudano-Sahelian Region (Somalia and Sudan, and, to a lesser extent, Eritrea) (Table 12). In the Central Region, only Cameroon has developed it, but on a small area (Table 27). On the other hand, equipped lowlands are frequent in countries with greater water resources, that is, in all regions except the Northern and Indian Ocean Islands Regions, as are cultivated non-equipped wetlands and inland valley bottoms. Finally, water use during flood recession is practised mainly in the Gulf of Guinea Region, to a lesser extent in the Sudano-Sahelian Region, and to a much lesser extent in the Indian Ocean Islands, Southern and Central Regions (Table 28).
Irrigation, which covers 13.4 million ha, is by far the most widespread form of water management in Africa (Figure 14, Figure 15). It accounts for 87 percent of the area under water management, of which almost half is concentrated in Northern Africa. Furthermore, 9.3 million ha, or about 70 percent, of the total area under irrigation are in five countries (South Africa, Egypt, Madagascar, Morocco and Sudan). The areas under spate irrigation (3 percent) and equipped lowlands (4 percent) are greatly exceeded by areas under full/partial control irrigation, representing 93 percent of the area under irrigation (Table 12). At regional level, the proportion of irrigation in the areas under water management ranges from 100 percent in the Northern Region to 30 percent in the Central Region. However, the latter region accounts for more than 70 percent of the non-equipped cultivated wetlands and inland valley bottoms on the continent (Table 11). Its wetter climate ensures the presence of numerous humid lowlands (in the Democratic Republic of the Congo, Angola, Congo, Equatorial Guinea, Cameroon, Central African Republic, etc.).
Irrigation is practised on 6 percent of the total cultivated area of the continent (Table 12 and Table 27). This percentage is much lower than that for other regions: 38 percent in Asia, 27 percent in the Caribbean, and 12 percent in Latin America. However, this overall average value, linked directly to the amount of precipitation, ranges from practically zero in the Central African Republic to 100 percent in Egypt, where farming would be impossible without irrigation (Table 27).
Full/partial control irrigation techniques
Table 13 presents the regional distribution of irrigation techniques used on areas under full/partial control irrigation. For countries where techniques were described in the previous publication and where no new data are available, this analysis uses the earlier values (Table 29). The Sudano-Sahelian and Central Regions are those whose data are the most deficient. Indeed, data on the type of techniques used in full/partial control irrigation are available for only one-eighth and one-quarter of their respective areas. According to the field knowledge of the AQUASTAT team, countries where data are missing practise mainly surface irrigation. Therefore, the totality of their area under full/partial control irrigation is included under the "surface irrigation" technique of the regional analysis (this estimation is not mentioned in the country profiles). Surface irrigation greatly exceeds pressurized irrigation techniques (sprinkler and localized).
Pressurized irrigation techniques are concentrated mainly in the Northern and Southern Regions. In percentage terms, sprinkler irrigation is the most widespread technique in the Southern Region. In the Northern Region, it is practised on a similar area, but it represents a lesser proportion because surface irrigation covers an area nearly five times as large. In the Gulf of Guinea, Eastern and Central Regions, the area under sprinkler irrigation is much more limited. The Sudano-Sahelian and Indian Ocean Islands Regions only have a very small percentage of their area under sprinkler irrigation. Finally, localized irrigation has only really developed (except in pilot areas) in the Northern and Southern Regions. These regions are dry but also contain some of the most developed countries of the continent.
Origin of water in full/partial control irrigation
Table 14 presents available data concerning the origin of irrigation water in the areas under full/partial control irrigation: surface water, groundwater or other (mix of groundwater and surface water, or non-conventional water). Data are available for all the countries of the Northern Region, water resources management in dry climates being a primary element for the sustainability of irrigation systems. Conversely, it is little known in the countries of the Eastern, Sudano-Sahelian and Central Regions.
For countries that did not supply new data, this analysis has used those from the previous AQUASTAT survey (Table 30). Most of the countries for which few or no data are available withdraw mainly surface water to feed their irrigation systems. An estimate (100 percent surface water, 50 percent surface water - 50 percent groundwater, or 100 percent groundwater) has been made for these countries in order to enable a more complete analysis. Finally, for the earlier data, the percentages for each of the sources were retained and applied to areas under full/partial control at present. Therefore, these values are in order of magnitude only and are not an exact reflection of the real situation (like those in Table 13). However, it seemed worth attempting to complete the data based on the field knowledge of the AQUASTAT team in order to form a more precise picture of the sources of water used for irrigation in Africa.
With respect to "other sources", Algeria, Botswana and Guinea-Bissau use a mix of surface water and groundwater, while Egypt, Libyan Arab Jamahiriya, and Tunisia have started using treated wastewater to increase their water resources (Table 14 and Table 30).
Surface water is the main source of the water for irrigation systems on the continent level (78 percent). Only Algeria, Eritrea, Libyan Arab Jamahiriya, and Tunisia (four countries with a dry climate in the Northern and Sudano-Sahelian Regions) feed their irrigation systems mainly with groundwater. Except for Eritrea, areas under irrigation in the other three countries are close to the irrigation potential calculated on the basis of renewable water, or exceed it (70-1 175 percent of the potential). Algeria and Libyan Arab Jamahiriya withdraw non-renewable fossil groundwater to meet their agricultural water requirements.
The definition of large schemes varies from one country to another. While certain countries consider a scheme of 25 ha as large, many countries use a minimum area of 500 ha. Schemes of more than 1 000 ha exist in about two-thirds of the 53 countries. Those of more than 10 000 ha exist in nearly one-quarter of the countries, representing almost half of the total area under irrigation. The only truly large scheme in Africa is the Gezira-Managil scheme in the Sudan with an area of about 870 000 ha, which is irrigated with water from the Blue Nile River thanks to the Sennar Dam. There are several schemes of more than 100 000 ha in Egypt, Morocco and Sudan. Schemes of more than 50 000 ha are also found in these three countries and in Algeria, Mali and Tunisia. Generally speaking, the schemes are smaller than in Asia.
Rather than by its size, a scheme is often described by its type of management: small private farms, commercial farms, communal schemes or public schemes. A distinction is also often made between "small-scale and medium-scale irrigation schemes" and "large-scale irrigation schemes", the latter being implemented by governments.
Only five countries (South Africa, Egypt, Madagascar, Morocco and Sudan) in Africa have a total area under water management of more than 1 million ha, compared with 20 countries in Asia.
IRRIGATED CROPS IN FULL/PARTIAL CONTROL IRRIGATION SCHEMES
Table 15 shows the regional distribution of irrigated crops for countries that have provided such information. The equipped areas with several crop cycles a year are counted several times, which explains why the total is superior to the physically equipped areas given in Table 12. This also gives an idea of the cropping intensity under irrigation (see below). Finally, the values from the previous AQUASTAT survey were used for countries with no new data in order to obtain a more complete picture of irrigated crops in Africa. Only six countries do not have any values. The Northern and the Southern Regions are the only ones for which all the countries have data, and the values for these regions are closer to the real situation. However, in all the regions, the country-level data are not necessarily complete and, therefore, precision is lacking. Therefore, the analysis that follows should be considered with caution.
Cereals (including rice) represent about 45 percent of the harvested irrigated crop area. Industrial crops follow with 15%, of which sugar cane constitutes about one-quarter (4%). Irrigated fodder is the third most widespread crop, representing 14 percent. Vegetables (high-value crops) follow with 12 percent. Tree crops represent only 4 percent and roots and tubers only 3 percent of the harvested irrigated crop area. Cereals are the dominant crops in all the regions except the Gulf of Guinea Region, where vegetables (31 percent) are the most important irrigated crop in terms of area.
Irrigated fodder is cultivated mainly in the Northern Region, and more precisely in Egypt (which possesses about two-thirds of irrigated fodder in Africa, notably the Alexandria clover or Trifolium/Bersim). It is also cultivated also in the Southern Region in a much lower proportion and in the Sudano-Sahelian Region, where its cultivation is concentrated in the Sudan, whose northern part could be assimilated with the Northern Region because of its similar geographical and climate characteristics (Table 31). Madagascar accounts for half of the area under rice in Africa, and the Northern Region for almost one-third. However, this crop is cultivated in all the regions. Root and tuber crops (mainly potatoes, sweet potatoes, and sugar beets) are most significant in the Northern Region, although they are also cultivated in the Southern, Eastern and Sudano-Sahelian Regions. Cotton is the main industrial crop and covers an area larger than that under sugar cane. Cotton cultivation is concentrated in some countries: Egypt in the Northern Region, Sudan in the Sudano-Sahelian Region, South Africa and Zimbabwe in the Southern Region, and Ethiopia in the Eastern Region. Other industrial crops are: olives (mainly in Morocco in the Northern Region), peanuts (the Northern, Sudano-Sahelian and Southern Regions), sunflowers, bananas, tobacco, tea, coffee, and soybeans. Fruit trees, dominated by citrus fruits (61 percent), are found mainly in the Northern Region while in the Southern Region they are in much smaller numbers; other regions do not cultivate them (Indian Ocean Islands and Gulf of Guinea Regions) or their cultivation is minor (Central and Eastern Regions). Finally, the irrigated cultivation of vegetables has developed considerably in recent years, accounting for almost the entire increase in irrigated area.
The Northern Region accounts for about 60 percent of the harvested irrigated crop area but only 47 percent of the physical irrigation area. This implies a higher cropping intensity than for the whole of Africa. With 14 percent of the harvested irrigated crop area, the Southern Region ranks second in terms of irrigated crop production. With a similar percentage of equipped area on the continent (15 percent), the cropping intensity is therefore lower. Incomplete data for the other regions prevent the determining of their cropping intensity. The following section provides data on cropping intensity for those countries where information was available.
LEVEL OF USE OF AREAS EQUIPPED FOR IRRIGATION
On the continental level, it is difficult to calculate the area of the equipped areas actually irrigated because information is missing for about ten countries in both AQUASTAT surveys. Where a country did not have new data, those of the previous survey were used. Finally, this analysis used an estimation of 80 percent of equipped area for countries without any data in order to obtain a more complete picture. This figure corresponds to the average percentage of use for the whole of Africa when only available data (recent and older) are considered.
Use rates vary considerably among those the countries that supplied such data. They range from 2.5 percent for Lesotho (only 67 ha of the equipped 2 637 ha were actually irrigated in 1999, the remaining area corresponding to schemes where the equipment for sprinkler irrigation received during the apartheid period has never really functioned) to 100 percent for Egypt, Guinea, Guinea-Bissau, South Africa and Zambia, while Madagascar, Mauritius, Morocco, and Tunisia also have rates exceeding 98 percent. Eight countries (Angola, Benin, Congo, Djibouti, Lesotho, Mozambique, Somalia, and Sudan) have use rates lower than 50 percent (Table 27). In numerous cases, low rates are explained by a deterioration in the infrastructure owing to a lack of maintenance (caused by a lack of experience or the use of non-adapted techniques) or political and economic reasons. However, other causes are: inadequate management of technical means of production under irrigation, soil impoverishment, local instability and insecurity, and the reduction of public funds allocated to irrigation.
On the regional level, the Indian Ocean Islands Region, especially influenced by Madagascar, uses practically all its areas equipped for irrigation (Table 16). The Northern and Southern Regions, with more than 90 percent of their equipped areas actually irrigated, also make good use of their equipment. However, use rates are low in the Sudano-Sahelian Region, mainly because of the Sudan. The equipped areas in the Sudan that are not actually irrigated represent 41 percent of the equipped area in the region. Countries responsible for the low use rate in the Central Region are mainly Angola, followed by the Central African Republic and Congo, their actually irrigated area being 44, 51 and 11 percent, respectively (Table 27).
Cropping intensity, another indicator of the use of equipped areas, was only calculated for 19 countries owing to the lack of data (Table 17). The calculation of cropping intensity is simple for dry countries because irrigation is indispensable for crops in all seasons. However, the calculation is more problematic for countries with one or more wet seasons. For two crop cycles a year, only one is irrigated (during the dry season), the second uses soil moisture provided by the precipitation. Therefore, the cropping intensity (irrigated crops only) is 100 percent on the area considered, while the harvested area is double.
TRENDS IN THE LAST TEN YEARS
In 1994, the population of Africa was 689 million people, slightly more than 12 percent of the world’s population. In 2004, it was 868 million people, or about 14 percent of the world’s population. In 1994, about 66 percent of the African population lived in a rural environment compared with 61 percent in 2004 (Table 1 and Table 23). This indicates that the rural exodus towards cities has not stopped stop but, on the contrary, it has continued. The rate of population growth in the period 1994-2004 was 2.6 percent/year, a sharp decrease compared with the 3.1 percent/year for 1984-1994. Finally, in 1994, the population density for the continent as a whole was 23 inhabitants/km2 compared with 29 inhabitants/km2 in 2004. This increase of 6 inhabitants/km2 in the period 1994-2004 was the same as that in the period 1984-1994.
On a sectoral basis, the proportions of water withdrawals have remained almost unchanged with agriculture remaining the main water consumer (Figure 3). However, total withdrawals have grown by 43 percent. Between the two survey dates, withdrawals per inhabitant also increased (by 35 m3). This growth, which is much larger in SSA than in the Northern Region, reflects both the increase in the population and an increase in per-capita consumption. Finally, the Northern Region which accounted for 51 percent concentrated of total water withdrawals in Africa in the previous AQUASTAT survey, has seen its portion fall with SSA now accounting for 56 percent of total withdrawals (Table 18).
The countries with data on non-conventional resources are practically the same as in the previous publication. The volume of wastewater produced has increased by nearly 60 percent, while the volume of treated wastewater increased by a factor of more than seven and the volume of reused treated wastewater rose by a factor of nine. However, available data indicate that the volume of desalinated water remained practically unchanged. However, these results may reflect not only real increases but also data adjustments. As a final point, it should be noted that the search for new water resources under all forms is very intense in about 15 countries, notably in the drier areas of the Northern, Sudano-Sahelian and Southern Regions.
Irrigation and areas under water management
Table 19 presents the trends in these areas since the previous AQUASTAT report on Africa in 1995. In Africa, the area under water management has increased by 1.18 million ha (8 percent) in the last ten years. This expansion is mainly the result of an increase in equipped areas (10 percent) at the expense of non-equipped areas, i.e. non-equipped cultivated wetlands and inland valley bottoms and non-equipped flood recession cropping (Figure 4). These latter types of water management contracted at an annual rate of 4.5 percent in this period. The most marked change relates to equipped lowlands. This development is explained by the development of small irrigation schemes that use techniques that do not allow full water management, but which are less expensive. It is also probable that some non-equipped cultivated wetlands and inland valley bottoms and non-equipped flood recession cropping areas have been equipped. Therefore, these are added to the "equipped lowlands" or "partial/full control irrigation" categories, which translates into a trend of increasing equipped areas.
For the whole continent, the increase in the equipped area is 10 percent, an annual rate of 0.88 percent in the 1992-2000 weighted year index (Table 20). The weighted year index is calculated by allocating to the year for each country a weighting coefficient proportional to its area (equipped for irrigation or under water management), therefore giving more importance to countries with the largest areas under irrigation and water management. On a national scale, the expansion in equipped areas has been concentrated in a few countries, with four countries (South Africa, Morocco, Egypt and Zambia) accounting for nearly 60 percent of the total increase. Although the increases in equipped areas may not be as important, other countries have also shown considerable rates of increase (Table 27). However, the rate of annual increase in Ghana, the highest in Africa (30 percent), is distorted by informal irrigation that, although probably already existing, was not included in the data in the previous survey. Moreover, the area under traditional irrigation was underestimated for Ethiopia. The increase in irrigated areas in Mali (20.1 percent) is explained by the reclassification of areas previously indicated as non-equipped, which were this time accounted for as equipped areas because of better knowledge of the field situation. The increase in equipped areas in Zambia (12.9 percent) is accounted for by the equipping of areas that were non-equipped in 1992 during the first survey; indeed, the total area under water management has increased only slightly (5.7 percent). The same holds for Rwanda (11.4 percent), even though its total area under water management fell between 1993 and 2000, and again for Senegal (6.7 percent and 0.7 percent, respectively). The annual rate of increase in areas under water management is 0.73 percent, slightly lower than that of the areas equipped for irrigation (0.88 percent). For Guinea-Bissau, a more detailed inventory (1994-96) enabled a more accurate assessment of the irrigated areas, but it is not possible to speak of a real increase. Finally, the Sudan shows a drop in its areas equipped for irrigation. This is the consequence of some of its equipment being so severely degraded that it has become unusable and even beyond rehabilitation.
Available data on irrigation techniques in 1995 covered only half of the areas under full/partial control irrigation. In the present update, they concern 77 percent of these areas. Therefore, it is difficult to analyse the trends in the different irrigation techniques. A careful estimate would show that the proportion of area under surface irrigation has decreased in favour of techniques requiring less water, such as sprinkler irrigation and in particular localized irrigation (whose area has increased by a factor of almost six). The area covered by sprinkler irrigation has more than doubled, almost all of the increases being in the Southern Region, while localized irrigation is well developed in both the Northern and Southern Regions. Although these regions include the driest countries on the continent, these countries are also the among most developed, two factors favouring the adoption of these techniques.
The main change in the last ten years has been a decrease in rice-growing areas and their proportion in the whole area under full/partial control irrigation. This reduction has occurred mainly because of the increase in the area under vegetables. This increase has been particularly marked in the Southern Region. The area under industrial crops has also increased, indicating that a higher percentage of irrigated area is dedicated to these crops, while the proportion of areas under sugar cane only has remained unchanged. The area under root and tuber crops has also increased, especially in the Northern Region. Areas allocated to arboriculture and to fodder crops have increased, but their respective proportion of irrigated areas has remained the same. Finally, the decline in irrigated crop areas in the Gulf of Guinea Region and in rice growing in general is reflected by the removal of the Nigerian "fadamas" from the category of harvested irrigated crop areas. In this new survey, this category includes only areas under full/partial control irrigation.
Use rate of areas equipped for irrigation
Among the countries for which information is available, four have seen their rate of use for equipped areas improve in the last ten years. Areas actually irrigated in Algeria increased from 66 percent of equipped areas in 1992 to 80 percent in 2001 (while there was also a small growth in equipped areas). The same holds for the Libyan Arab Jamahiriya (from 51 percent in 1990 to 67 percent in 2000, for identical equipped areas), Madagascar (from 82 percent to 99.5 percent between 1992 and 2000, for practically the same equipped areas) and Tunisia (from 84 percent in 1991 to 99.7 percent to 2000, for increased equipped areas). Conversely, three countries have experienced a reduction in the use of their irrigation systems. In Lesotho, the area actually irrigated declined from 7 percent of equipped areas in 1994 to 3 percent between in 1999, for the same equipped areas. In Mozambique the use rate fell from 42 percent to 34 percent between 1995 and 2001, for a slight increase in equipped area. While a more extensive use of equipped areas in the first group of countries can be explained by the rehabilitation of degraded schemes, it is often the degradation of equipment that justifies the abandonment of equipped areas in the latter group of countries. Finally, among those countries with a current use rate of less than 50 percent, the Sudan has experienced considerable degradation, with the area actually irrigated declining from 63 percent in 1995 to 43 percent in 2000.
Water management in African countries is generally based on a water code. Thirty-seven countries have such a code for governing in a global way the management of water resources present on their territory. Three other countries (Gabon, Seychelles and Sudan) have included water in their legislation on the environment or on natural resources although they have no specific water law. In six other countries (Central African Republic, Democratic Republic of the Congo, Libyan Arab Jamahiriya, Rwanda, Sao Tome and Principe, and Swaziland), certain aspects of water management such as pollution, drilling or water rights are regulated, but these specific arrangements are not grouped in a water code. Five countries (Gambia, Ghana, Liberia, Sierra Leone, and Somalia) have institutions responsible for water supply or water management, but without clear definitions as to the direction that this water management should take. Finally, no information was available for two humid countries, the Comoros and Equatorial Guinea. Somaliland, in the north of Somalia, has formulated its own water policy and is working on the constitution of a water code. Of the 37 countries with a comprehensive legal framework, 25 have drafted, amended or applied it since 1995, which indicates the topicality of the subject. However, Eritrea has not yet approved its water law drafted in 1996. Finally, legislation focusing more specifically on irrigation management is rare. Only Mauritius, Kenya and Malawi have enacted an irrigation law, in 1979, 1996 and 2001, respectively. FAO has ongoing projects to assist governments in setting up a strategy for the irrigation sector and to formulate an irrigation policy in the following countries: Botswana, Eritrea, Ghana, Nigeria, Swaziland, United Republic of Tanzania, and Zambia.
The national-level institutions responsible for the management and planning of irrigation development are, for a large majority of African countries (41 out of 53), departments or divisions within the Ministry of Agriculture (37) or within the Ministry of Agriculture and Irrigation or Water Resources (4). However, the management and conservation of water resources are generally the responsibility of another ministry (of environment, natural resources, energy or water resources), and coordination between these national institutions is almost non-existent. Only Burundi, Guinea-Bissau, Mozambique and Senegal have created an interministerial committee for actions to be undertaken in synergy. Six countries have only entrusted part of their irrigation to the Ministry of Agriculture, distributing the management of the sector between several ministries (Benin, Libyan Arab Jamahiriya, Morocco, Mauritania, Sudan and Zimbabwe). Finally, only four countries have a Ministry of Water Resources that includes irrigation management: Algeria, Egypt, Kenya and Nigeria, which account for 43 percent of the area under water management in Africa. In Congo and Guinea, irrigation is the responsibility of the Ministry of Water Resources, Minerals and Energy.
The management of the irrigation systems is generally ensured jointly by the State, as regards the primary infrastructure or public systems, and by users associations for the secondary and tertiary infrastructure or private systems. The disengagement of the State from the irrigation sector since the 1980s, and the subsequent creation of users associations that are already in place or planned (South Africa, Burundi, Côte d’Ivoire, Ghana, Madagascar, Mali, Morocco, Mauritius, Niger, Nigeria, Senegal, Sudan, Swaziland, Tunisia and Zimbabwe), as well as the more recent promotion of participatory approaches (Burkina Faso, Mauritania and Chad) concerns about 20 African countries. The example of Kenya illustrates well the choice of management transfer; indeed, all the new schemes created between 1992 and 2003 are private, while certain former public schemes are still partially administered by the State. In Egypt, rather than a transfer to the users, the government has chosen to promote their participation by replacing its formerly very centralized management with a form of joint management.
Informal irrigation, notably in the urban and peri-urban zones of large African cities, has become increasingly important. This irrigation is generally not included in official statistics or in the integrated management of resources. It is probably not included in AQUASTAT statistics (or is only partially included) for most countries because of the difficulty in obtaining data. Its growth and development are explained by the disengagement of the State in the irrigation sector and the development of private irrigation. It is generally carried out on a small scale, but represents a significant added value for each of the farmers in terms of income. It is difficult to estimate this type of irrigation on a continental scale.
Water tariffication is used in only 27 countries, 23 of which envisage charges, mainly based on irrigated area. In nine countries, it is supposed that water charges are heavily subsidized (Chad and Namibia), applied only to large schemes (Morocco), applied rarely in spite of the law (Togo and Côte d’Ivoire), or cover only the costs of operation and maintenance (Madagascar). Water and irrigation services are free in Botswana, Ethiopia, Libyan Arab Jamahiriya and Somalia.
ENVIRONMENT AND HEALTH
Of the 29 countries for which information concerning water quality is available, 12 (Benin, Burkina Faso, Cameroon, Chad, Congo, Ghana, Guinea, Libyan Arab Jamahiriya, Malawi, Mozambique, Senegal and Zimbabwe) assert that their water is of a quality relatively suitable for irrigation and that pollution is site specific and limited mainly to human settlements without sanitation infrastructure (urban area) and to agriculture where it is mainly the result of concentrations of livestock. For the other 17 countries, agriculture is mentioned as the main source of pollution, e.g.: Algeria, Mali (in the zone of the Office of Niger), Mauritius (mainly because of sugar cane), Sudan, Swaziland (because of animals that contaminate sources), Togo (where agricultural pollution only affects surface water), and Tunisia. Among other sources of pollution, a combination of agriculture, industry and domestic waste are mentioned (Democratic Republic of the Congo, Sao Tome and Principe, Somalia, and South Africa) and, to a lesser extent, the mining industry (petroleum in the Niger Delta in Nigeria, and diamonds in Botswana and Lesotho). In the Comoros, Eritrea and Rwanda, it is population density and domestic waste that degrade water quality.
The overexploitation of aquifers (when water withdrawal exceeds water recharge) and the subsequent lowering in their levels is a problem in seven countries: Algeria, Cape Verde, Djibouti, Morocco, Nigeria, Senegal and Tunisia; a problem that can also be found in the coastal aquifers of the Comoros and the Libyan Arab Jamahiriya. This overexploitation is at the origin of seawater intrusion in Algeria and Cape Verde. Eritrea and Mauritius (in the north and east) are also affected. Finally, the use of fossil water, that is, water from aquifers whose rate of renewal is very low and that are therefore considered as non-renewable (notably in the Libyan Arab Jamahiriya and to a lesser extent in Algeria), will cause depletion of the aquifers in the long term.
Soil salinization is a problem in 14 countries in Africa. The situation is of particularly concern in Morocco, Nigeria and Sudan, where the area salinized by irrigation exceeds 100 000 ha (Table 21) although less so in Kenya, Tunisia and United Republic of Tanzania. Salinization also requires monitoring in: Djibouti, Gambia and Mozambique, where soils are naturally saline; Namibia; Niger, where 350 ha have been abandoned and others risk being so shortly; Somalia; and Zimbabwe. Finally, Egypt has controlled its salinization since the 1970s on a large part of its irrigation schemes through the installation of drainage systems (Box 1).
Other major environmental problems related to irrigation in Africa are: (i) erosion and its consequences and silting up or sedimentation of water bodies, dams and canals (ten countries); (ii) proliferation of aquatic vegetation (six countries); and (iii) the drying up or the risk of drying up of wetlands (four countries) (Box 2).
An estimated 70-90 percent of all cases of malaria in the world occur in Africa. Africa remains by far the worst affected continent, with 365 million cases of malaria in 2002. The WHO (2005) report on malaria in Africa indicates that malaria is the cause of at least one death in five among very young children. More than 80 percent of deaths caused by this pathology occur in Africa, where it threatens an estimated 66 percent of the population. According to the WHO, the only African countries where the disease is not endemic are Lesotho, Libyan Arab Jamahiriya, Seychelles and Tunisia.
PERSPECTIVES FOR WATER MANAGEMENT IN AFRICA
Numerous countries in Africa consider water and irrigation management as a key factor to improving their food security and to ensuring access to drinking-water for their populations.
Although they already exist, water transfers are still rare. They take place either within the same country such as in Morocco (for a volume of 2.7 km3 between river basins) and in the Libyan Arab Jamahiriya (transfer of fossil groundwater resources between the south and the north through the "Great Manmade River Project") or between countries, the only example currently known being the transfer of 2.2 km3/year from the Malibamatso River in Lesotho to the Vaal River in South Africa (both in the Orange basin) within the framework of the "Lesotho Highlands Water Project". In compensation, Lesotho receives assistance in the production of its own electricity (Table 25). Many projects to develop such transfers are being studied: in Algeria, from the south to the north; in Kenya, from Lake Victoria towards drier zones such as the Kerio in the Rift Valley, or towards the Vembere plateau (a project dating back to the German colonial period); in Botswana, between the Shashe and the Notwane rivers, both in the Limpopo basin; and water flowing towards Lake Chad to compensate for the decrease in water levels (from the Niger Basin in Nigeria, or from the Congo Basin) (Box 2).
According to available information, the current use of non-conventional sources of water (desalination, and reuse of treated wastewater) concerns less than one-third of the countries. This should develop considerably in the future in order to mitigate the lack of available resources in numerous dry countries.
The two trends confirming a net progress in water management in African countries are integrated water resources management (IWRM) and the development of small-scale irrigation. The former appears in different policies or legislative proposals, and accompanies the protection of water resources to guarantee their long-term sustainability. Eight countries have incorporated IWRM into their policies or have proposed doing so. As for small-scale irrigation, it is the main type of construction retained by countries still trying to develop their irrigated area. It envisages management by the users and their more active participation, and it often goes hand in hand with the introduction of lower-cost technologies (treadle pumps, "drip kits", etc). Countries that have already developed their irrigation potential, such as South Africa or Libyan Arab Jamahiriya, no longer carry out construction work, rather, they have undertaken the development of more efficient techniques for water use (sprinkler and localized irrigation) with the aim of reducing the water volume used for crops.
Finally, in the last ten years, one of the trends in irrigation has been to equip areas previously under surface water management, such as inland valley bottoms and flood recession areas. This approach has enabled development costs to be reduced and irrigation to be increased and, therefore, raised the productivity of agricultural land. This trend can be expected to continue in the next few years with the aim of intensifying irrigation on the most easily irrigable lands.
MAIN SOURCES OF GENERAL INFORMATION
Documents cited in this section were useful for the writing of the summary and are not specific to a country. Literature relative to the individual countries is listed in the section "Main sources of information" at the end of each country profile.
Bucks, D.A. 1993. Micro-irrigation world wide usage report.
CILSS/OECD. 1991. The development of irrigated crops in Sahel. Summary and reports by country. OECD / CILSS / CLUB of Sahel. SATURDAY / D (91) 366. E/F.
FAO. 1986. Irrigation in Africa south of the Sahara. Technical document No. 5 of the investment centre of the FAO. Rome. 181 pp.
FAO. 1995. Irrigation in Africa/L’irrigation en Afrique en chiffres. FAO Water Report No. 7. Rome.
FAO. 1997a. Irrigation in the Near East Region in figures. FAO Water Report No. 9. Rome.
FAO. 1997b. Irrigation in the countries of the former Soviet Union in figures. FAO Water Report No. 15. Rome.
FAO. 1997c. Irrigation potential in Africa - a basin approach. FAO Land and Water Bulletin No. 4. Rome.
FAO. 1999. Irrigation in Asia in figures. FAO Land and Water Bulletin No. 18. Rome.
FAO. 2000. Irrigation in Latin America and the Caribbean in figures. FAO Land and Water Bulletin No. 20. Rome.
FAO. 2004a. Drought impact mitigation and prevention in the Limpopo River Basin - a situation analysis. FAO Land and Water Discussion Paper No. 4. Rome.
FAO. 2004b. Directions for agricultural water management in Africa. FAO Land and Water Development Division. Unpublished.
FAO. 2005a. Factors affecting the development and management of water resources for agriculture in the Lake Chad basin. FAO-AGLW internal notes.
FAO. 2005b. Factors affecting the development and management of water resources for agriculture in the Nile Delta. FAO-AGLW internal notes.
FAO. 2005c. Large hydro-electricity and hydro-agricultural schemes in Africa. FAO-AGLW internal notes.
FAO. 2005d. FAOSTAT - database (available at http://faostat.external.fao.org/).
FAO. 2005e. AQUASTAT - database (available at http://www.fao.org/).
Gleick, P.H., ed. 1993. Water in crisis: a guide to the of world’s freshwater resources. New York, USA, Oxford, UK, Oxford University Press for Pacific Institute. 473 pp.
Gleick, P.H., ed. 2004. The world’s water 2004-2005: the biennial report on freshwater resources. Washington, DC, Island Press.
ICID. 2005. Sprinkler and micro-irrigated area in some ICID member countries (available at http://www.icid.org).
IPTRID/FAO. 2003. The irrigation challenge - increasing irrigation contribution to food security through higher water productivity canal irrigation systems. Issue paper No. 4.
L’vovitch, M.I. 1974. World water resources and their future. Russian ed. Mysl. Moscow. Translation in English by R.L. Nace, American Geological Union, Washington, 1979. 415 pp.
Margat, J. 1991. Ressources en eau des pays africains, utilisation et problèmes. VII Congrès mondial des ressources en eau. May, 1991, Rabat, Morocco. IWRA / AREA. 21 pp.
Margat, J. 1994. Les ressources en eau des pays de l’OSS- Evaluation, utilisation et gestion. Observatoire du Sahara et du Sahel, Paris. 83 pp.
UNDP. 2005. Human Development Index (available at http://hdr.undp.org).
UNESCO. 1972. Etudes des ressources en eau du Sahara septentrional. Final report + 7 technical annexes.
UNICEF/WHO. 2005. Joint Monitoring Programme (JMP) for water and sanitation (available at http://www.unicef.org).
UNICEF. 2005. Statistics by country (available at http://www.unicef.org).
United Nations. 1987. Groundwater in Western and Northern Africa. UN-DTCD Natural Resources Water Series No. 18.
United Nations. 1988. Groundwater in Eastern, Central and Southern Africa. UN-DTCD Natural Resources Water Series No. 19.
WHO. 2005. World malaria report 2005.
World Bank. 2005. Indicators of world development (available at http://www.worldbank.org).
World Conservation Union (UICN). 2005. Towards an agency for Volta Basin?
World Resources Institute. 1994. World resources 1994-1995. A guide to the global environment. Oxford University Press for WRI/UNEP/UNDP. 400 pp.
World Resources Institute. 2003. World resources 2002-2004. Decisions for the earth: balance, voice, and power.
The following summary tables are available for Africa:
- Summary table 22: Land use and irrigation potential,
- Summary table 23: Population characteristics,
- Summary table 24: Renewable water resources,
- Summary table 25: Large dams by major river basin in Africa,
- Summary table 26: Water withdrawals,
- Summary table 27: Area under irrigation,
- Summary table 28: Water managed area,
- Summary table 29: Full/partial control irrigation techniques,
- Summary table 30: Origin of full/partial control irrigation water,
- Summary table 31: Harvested irrigated crops on full/partial control areas,
- Summary table 32: Africa compared to the world.
- The cultivated areas for Djibouti and Egypt do not correspond to the FAOSTAT data because these latter were lower than the areas equipped for full/partial control irrigation owing to rounding of the FAOSTAT values.
- The percentages of effectively irrigated areas do not correspond to the year indicated in the first column for Angola (1996), Democratic Republic of the Congo (2000), Gambia (1991), Guinea (2000), Malawi (1992), Mauritius (2004), Niger (2005), and Swaziland (2002).
- Ghana’s high annual increase in the rate of irrigation (30.1 percent) is the result of including informal irrigation which, although already existing, was not included in the areas equipped for irrigation in the previous AQUASTAT survey.
- An inventory in Guinea-Bissau between 1994 and 1996 has enabled better knowledge of the areas.
- The sharp increase in areas equipped for irrigation in Mali (20.1 percent/year) is explained by the addition of areas previously declared as non-equipped. However, this reclassification is not the result of new investment in these areas, only the appreciation of the level of equipment has changed.
- The rate for the Sudan is negative (-0.9 percent/year) because the degradation of certain schemes is such that they are no longer usable or beyond rehabilitation.
- For Rwanda, Senegal and Zambia, the high rates of increase correspond to the equipping of areas that were previously not equipped, and so to a move of certain areas from the “non-equipped” to the “equipped” category. However, the total areas under water management have not undergone such an important increase.
- The areas under water management exceed the irrigation potential in the Libyan Arab Jamahiriya and in Algeria because the irrigation potential takes into account only renewable water resources and these countries also use non-renewable resources, mainly fossil groundwater.
- The data on irrigation techniques are not complete for all African countries.
- The sum of areas with the various irrigation techniques in Botswana and Malawi is not equal to the area equipped for full/partial control irrigation because they do not refer to the same year.
- Data on the origin of irrigation water are not complete for all countries.
- The total area of irrigated crops (column 3) appears only for those countries for which the total of harvested irrigated crops is known (thus enabling calculation of the cropping intensity and the percentage of the main irrigated crop).
- For Morocco, the physical actually irrigated area used for the calculation of cropping intensity (1 406 560 ha) refers to 2000, in order to correspond with the year of the areas of harvested irrigated crops. Therefore, it differs from the one indicated in the profile (the most recent value dating from 2004).
The following continental maps are available for Africa:
- Figure 5: Regional Division of Africa,
- Figure 6: Average annual rainfall,
- Figure 7: Population density,
- Figure 8: Internal renewable water resources,
- Figure 9: International river basins,
- Figure 10: Annual water withdrawal per inhabitant,
- Figure 11: Annual water withdrawal as a percentage of internal renewable water resources,
- Figure 12: Irrigation potential by river basin,
- Figure 13: Water managed areas,
- Figure 14: Irrigation,
- Figure 15: Irrigation as a percentage of cultivated area.
- The total water withdrawal for agricultural, domestic and industrial purposes is
estimated at 63.8 km3, equal to 3 794 percent of the internal renewable water resources
(1.8 km3). Most of the water is withdrawn from the transboundary Nile River, of which
55.5 km3 is secured to Egypt by a treaty.
Libyan Arab Jamahiriya
- The total water withdrawal for agricultural, domestic and industrial purposes is
estimated at 4.3 km3, equal to 711 percent of the internal renewable water resources
(0.6 km3). A significant part of withdrawal comes from non-renewable groundwater
resources, mainly from fossil aquifers in south of the country.
- The total water withdrawal for agricultural, domestic and industrial purposes is
estimated at 1.7 km3, equal to 425 percent of the internal renewable water resources
(0.4 km3). Most of the water is withdrawn from the transboundary Senegal River but
no treaty guarantees its availability.
- The total water withdrawal for agricultural, domestic and industrial purposes is
estimated at 37.3 km3, equal to 124 percent of the internal renewable water resources
(30 km3). Most of the water is withdrawn from the transboundary Nile River but no
treaty guarantees its availability.