Africa > Renewable water resources

Africa: Renewable water resources

2013/10/09

 

Renewable water resources

Annual precipitation in Africa is estimated at about 20 360 km3, a continentwide average of 678 mm . Disparities between nations and regions are very significant. 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 nations in the Northern Region. This region is the driest region on the continent with an average of 96 mm/year. The nations 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. With additional than 7 500 km3/year, the Central Region receives 37 % of all precipitation in Africa in an area that accounts for less than 20 % of the total. In contrast, the Northern Region, with an area similar to the Central Region, receives less than 3 % of total precipitation.

Renewable water resources for the whole of Africa all to about 3 930 km3, or less than 9 % of world renewable resources (Figure 8 and Table 32). The Central Region is the best endowed, with 48 % of Africa’s resources for only 18 %of its sector. With 24 %  of Africa’s resources, the Gulf of Guinea Region is as well well supplied with water. On the other hand, the Northern Region is the majority disadvantaged with less than 1 %of the renewable water resources for an area equivalent to 19 % of Africa. The Democratic Republic of the Congo has 900 km3 of internal renewable water resources, 23 %of the total for African, while the Libyan Arab Jamahiriya has only 0.01 %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. 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 significant outside contributions (of the Nile River). Congo as well benefits from water resources from the Congo River from nations 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 nations .

With respect to internal renewable water resources, seven nations 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 nations 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 % 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 %), but a large part of this contribution (55.5 km3 or 98 %) is secured by a treaty with the Sudan, located upstream on the Nile River.

International waters

The major 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.

The water in these river basins, shared between several nations, is managed through basin organizations that group together all or some of the nations 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 major 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 nations of the Nile Basin (Nile COM), furthers a initial agreement in 1959 between Egypt and Sudan on the water of the river, and as well of the Committee of Technical Cooperation for the Promotion of the Development and the Environmental Protection of the Nile Basin (TECCONILE) in 1993. Part the ten nations 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 major 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 nations; 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, as well included in the lake basin, are not part of the \"conventional basin\". The major objectives of the LCBC are: (i) to conserve the limited water resources; (ii) to replace the water level in Lake Chad, which is one of the major 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 nations 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 nations 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 nations 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 equitable and reasonable use of the Zambezi water resources, inclunding 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 nations.

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 nations.

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-National Committee, created in 1963 and which as well 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 people of the basin and of the subregion; (ii) to fasten and improve incomes for people 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 nations located in the Limpopo River Basin (Botswana, Mozambique, South Africa and Zimbabwe) set up the Limpopo Basin Permanent Technical Committee (LBPTC), which restored the Permanent Technical Committee of the Limpopo Basin.

*An agency does not from presently on exist for the Volta River Basin, but its creation seems imminent. Part the six nations of the basin (Benin, Burkina Faso, Côte d’Ivoire, Ghana, Mali and Togo), Ghana and Burkina Faso have by presently 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 nations that share the Volta River Basin. It held its initial 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.

Dams

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. 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 additional than one-third of the total dam capacity on the continent (39 %), followed by the Gulf of Guinea Region (29 %) and the Northern Region (24 %), while the Central Region and the Indian Ocean Islands Region, the majority humid on the continent, have a small dam capacity . Five major dams (situated in the three regions with the highest capacity on the continent) total 565 km3 of capacity, or 71 % of the total capacity in Africa (Table 7). The dam with the major capacity is the Kariba Dam (188 km3). Additional 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 nations. These nations are in particular those whose renewable resources are limited and who by presently 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 nations seeking to increase their limited resources. The major nations 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 nations have as well 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 a lot of nations in these regions.

Water withdrawal

The data on water withdrawal refer to the gross quantity of water withdrawn annually for a given use. 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 data is available.

For most nations, the methods used for the calculation or the measurements for obtaining the values of the withdrawals are not specified. For the nations 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 % of the renewable water resources on the continent  and less than 6 % of world withdrawals. On a continental scale, 86 % of inventoried withdrawals are used for agriculture, a price higher than the world agricultural water withdrawal (70 % ). 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 % , respectively, of the total regional water withdrawal), while the Central Region uses only 56 % of its withdrawals for agriculture. The annual precipitation in this region allows rainfed agriculture, which is not feasible in the dry nations. Generally speaking, as in 1995, these are the nations that withdraw the highest volumes of water. Indeed, about 70 % 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 % ) and account for two-thirds of the irrigated areas (67 % ).

The regional-level values are influenced strongly by some nations: Egypt accounts for 73 %  of the withdrawals in the Northern Region; Sudan accounts for 67 % in the Sudano-Sahelian % ; Cameroon accounts for 49 % in the Central Region; Ethiopia and United Republic of Tanzania account equally for 76 % in the Eastern Region; Nigeria accounts for 65 % in the Gulf of Guinea Region; and South Africa accounts for 58 % in the Southern Region . Although they cover only 27 % of the continent, these seven nations account for 64 % of African water withdrawals. However, they are as well home to 47 % of its people and 67 % 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 . The region whose rate of water withdrawal (as a function of internal renewable water resources) is the lowest is the Central Region (0.1 % ), while the region with the highest rate of water withdrawal is the Northern Region (200 % ). 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).

Irrigation potential

The  irrigation potential by river basin. Because of this distribution by basin, water resources shared by several nations, 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 additional than 42.5 million ha, considering irrigation potential by basin and renewable water resources. One-third of this potential is concentrated in two very humid nations: Angola and the Democratic Republic of the Congo. For two nations, the irrigation potential is less than the area under water management . In Algeria, the area managed is 112 % of the potential while in the Libyan Arab Jamahiriya it is 1 175 % of the irrigation potential. These nations as well use non-renewable fossil groundwater for irrigation, whereas Figure 12 considers only renewable water resources. They are as well part the nations 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 initial large irrigation schemes. Since the end of the 1980s, the irrigation sector has undergone significant 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 by presently 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 additional 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 nations, or as a means to increase productivity and cropping intensity, and to favour crop diversity in the majority humid nations; hence, the large variety of techniques developed for water management.

ThR 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 . 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 additional 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). Additional than 40 % of the water managed area is concentrated in the Northern Region and the %age increases further at the same time as considering only those areas under irrigation. Egypt accounts for 54 % of the irrigated area in the Northern Region. The Sudano-Sahelian Region ranks second with 19 % of the water managed area and 20 % of the irrigated area. However, these figures reflect the area equipped for irrigation in the Sudan (71 % of the area equipped for irrigation in the region and 63 % of the area under water management). Finally, the Southern Region contains 15 % of the area equipped for irrigation and the water managed area on the continent. South Africa has a strong result on the figures for this region as it accounts for 73 % of its irrigation.

Spate irrigation is typical of dry nations. 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 other hand, equipped lowlands are frequent in nations with better 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

Irrigation, which covers 13.4 million ha, is by far the majority widespread form of water management in Africa. It accounts for 87 % of the area under water management, of which almost half is concentrated in Northern Africa. Furthermore, 9.3 million ha, or about 70 %, of the total area under irrigation are in five nations (South Africa, Egypt, Madagascar, Morocco and Sudan). The areas under spate irrigation (3 %) and equipped lowlands (4 %) are greatly exceeded by areas under full/partial control irrigation, representing 93 % of the area under irrigation .At regional level, the proportion of irrigation in the areas under water management ranges from 100 % in the Northern Region to 30 % in the Central Region. However, the latter region accounts for additional than 70 % of the non-equipped cultivated wetlands and inland valley bottoms on the continent . 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 % of the total cultivated area of the continent.. This % is much lower than that for other regions: 38 % in Asia, 27 % in the Caribbean, and 12 % in Latin America. However, this in general average price, linked due to the all of precipitation, ranges from practically zero in the Central African Republic to 100 % in Egypt, where farming would be impossible without irrigation.

Full/partial control irrigation techniques

Table 13 presents the regional distribution of irrigation techniques used on areas under full/partial control irrigation. For nations where techniques were described in the previous publication and where no new data are available, this analysis uses the before values . The Sudano-Sahelian and Central Regions are those whose data are the majority 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, nations 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 %age terms, sprinkler irrigation is the majority 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 additional limited. The Sudano-Sahelian and Indian Ocean Islands Regions only have a very small %age 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 as well contain some of the majority developed nations of the continent.

Origin of water in full/partial control irrigation

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 nations 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 nations of the Eastern, Sudano-Sahelian and Central Regions.

For nations that did not supply new data, this analysis has used those from the previous AQUASTAT survey .  Most of the nations for which few or no data are available withdraw mainly surface water to feed their irrigation systems. An estimate (100 % surface water, 50 % surface water - 50 % groundwater, or 100 % groundwater) has been made for these nations in order to enable a additional complete analysis. Finally, for the before data, the %ages 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 . However, it seemed worth attempting to complete the data based on the field knowledge of the AQUASTAT team in order to form a additional 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 .

Surface water is the major source of the water for irrigation systems on the continent level (78 % ). Only Algeria, Eritrea, Libyan Arab Jamahiriya, and Tunisia (four nations 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 nations are close to the irrigation potential calculated on the basis of renewable water, or exceed it (70-1 175 % of the potential). Algeria and Libyan Arab Jamahiriya withdraw non-renewable fossil groundwater to meet their agricultural water requirements.

Scheme sizes

The definition of large schemes varies from one country to an extra. While certain nations consider a scheme of 25 ha as large, a lot of nations use a minimum area of 500 ha. Schemes of additional than 1 000 ha exist in about two-thirds of the 53 nations. Those of additional than 10 000 ha exist in nearly one-quarter of the nations, 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 additional than 100 000 ha in Egypt, Morocco and Sudan. Schemes of additional than 50 000 ha are as well found in these three nations 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 as well often made between \"small-scale and medium-scale irrigation schemes\" and \"large-scale irrigation schemes\", the latter being implemented by governments.

Only five nations (South Africa, Egypt, Madagascar, Morocco and Sudan) in Africa have a total area under water management of additional than 1 million ha, compared with 20 nations in Asia.
Irrigated crops in full/partial control schemes

Table 15 shows the regional distribution of irrigated crops for nations that have provided such data. 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 as well gives an idea of the cropping intensity under irrigation . Finally, the values from the previous AQUASTAT survey were used for nations with no new data in order to obtain a additional complete picture of irrigated crops in Africa. Only six nations do not have any values. The Northern and the Southern Regions are the only ones for which all the nations 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 (inclunding rice) represent about 45 % 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 %. Vegetables (high-price crops) follow with 12 %. Tree crops represent only 4 % and roots and tubers only 3 % of the harvested irrigated crop area. Cereals are the dominant crops in all the regions except the Gulf of Guinea Region, where vegetables (31 %) are the majority significant irrigated crop in terms of area.

Irrigated fodder is cultivated mainly in the Northern Region, and additional precisely in Egypt (which possesses about two-thirds of irrigated fodder in Africa, notably the Alexandria clover or Trifolium/Bersim). It is as well cultivated as well 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. 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 as well cultivated in the Southern, Eastern and Sudano-Sahelian Regions. Cotton is the major industrial crop and covers an area larger than that under sugar cane. Cotton cultivation is concentrated in some nations: 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 %), 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 all increase in irrigated area.

The Northern Region accounts for about 60 % of the harvested irrigated crop area but only 47 % of the physical irrigation area. This implies a higher cropping intensity than for the whole of Africa. With 14 % of the harvested irrigated crop area, the Southern Region ranks second in terms of irrigated crop production. With a similar %age of equipped area on the continent (15 % ), 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 nations where data 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 data is missing for about ten nations 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 % of equipped area for nations without any data in order to obtain a additional complete picture. This figure corresponds to the average %age of use for the whole of Africa at the same time as only available data (recent and older) are considered.

Use rates vary considerably part those the nations that supplied such data. They range from 2.5 % 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 at no time really functioned) to 100 % for Egypt, Guinea, Guinea-Bissau, South Africa and Zambia, while Madagascar, Mauritius, Morocco, and Tunisia as well have rates exceeding 98 %. Eight nations (Angola, Benin, Congo, Djibouti, Lesotho, Mozambique, Somalia, and Sudan) have use rates lower than 50 % (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, particularly influenced by Madagascar, uses practically all its areas equipped for irrigation . The Northern and Southern Regions, with additional than 90 % of their equipped areas actually irrigated, as well 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 % of the equipped area in the region. Nations 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 %, respectively.

Cropping intensity, an extra indicator of the use of equipped areas, was only calculated for 19 nations owing to the lack of data . The calculation of cropping intensity is simple for dry nations because irrigation is indispensable for crops in all seasons. However, the calculation is additional problematic for nations with one or additional 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 % on the area considered, while the harvested area is double.
Trends in the last ten years

In 1994, the people of Africa was 689 million people, slightly additional than 12 % of the world’s people. In 2004, it was 868 million people, or about 14 % of the world’s people. In 1994, about 66 % of the African people lived in a rural environment compared with 61 % in 2004 . This indicates that the rural exodus towards cities has not stopped stop but, on the contrary, it has continued. The rate of people increase in the period 1994-2004 was 2.6 %/year, a sharp decrease compared with the 3.1 %/year for 1984-1994. Finally, in 1994, the people 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.

Water withdrawals

On a sectoral basis, the proportions of water withdrawals have remained almost unchanged with agriculture remaining the major water consumer . However, total withdrawals have grown by 43 %. Between the two survey dates, withdrawals per inhabitant as well increased (by 35 m3). This increase, which is much larger in SSA than in the Northern Region, reflects both the increase in the people and an increase in per-capita consumption. Finally, the Northern Region which accounted for 51 % concentrated of total water withdrawals in Africa in the previous AQUASTAT survey, has seen its portion fall with SSA presently accounting for 56 % of total withdrawals.

The nations 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 %, while the volume of treated wastewater increased by a factor of additional 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 as well 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 nations, notably in the drier areas of the Northern, Sudano-Sahelian and Southern Regions.

Irrigation and areas under water management

The trends in these areas since the previous AQUASTAT statement on Africa in 1995. In Africa, the area under water management has increased by 1.18 million ha (8 %) in the last ten years. This expansion is mainly the result of an increase in equipped areas (10 %) at the expense of non-equipped areas, i.e. non-equipped cultivated wetlands and inland valley bottoms and non-equipped flood recession cropping . These latter types of water management contracted at an annual rate of 4.5 %in this period. The majority 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 as well 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 %, an annual rate of 0.88 % in the 1992-2000 weighted year index . The weighted year index is calculated by allocating to the year for each country a weighting coefficient proportional to its sector(equipped for irrigation or under water management), therefore giving additional importance to nations with the major areas under irrigation and water management. On a national scale, the expansion in equipped areas has been concentrated in a few nations, with four nations (South Africa, Morocco, Egypt and Zambia) accounting for nearly 60 %of the total increase. Although the increases in equipped areas may not be as significant, other nations have as well shown considerable rates of increase.However, the rate of annual increase in Ghana, the highest in Africa (30 %), is distorted by informal irrigation that, although probably by presently 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 %) is explained by the reclassification of areas before 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 %) is accounted for by the equipping of areas that were non-equipped in 1992 during the initial survey; indeed, the total area under water management has increased only slightly (5.7 %). The same holds for Rwanda (11.4 %), even though its total area under water management fell between 1993 and 2000, and again for Senegal (6.7 % and 0.7 %, respectively). The annual rate of increase in areas under water management is 0.73 %, slightly lower than that of the areas equipped for irrigation (0.88 %). For Guinea-Bissau, a additional detailed inventory (1994-96) enabled a additional 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.

Irrigation techniques

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 % 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 additional 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 nations on the continent, these nations are as well the part most developed, two factors favouring the adoption of these techniques.

Irrigated crops

The major 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 as well increased, indicating that a higher %age 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 as well increased, particularly 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

Part the nations for which data 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 % of equipped areas in 1992 to 80 % in 2001 (while there was as well a small increase in equipped areas). The same holds for the Libyan Arab Jamahiriya (from 51 % in 1990 to 67 % in 2000, for identical equipped areas), Madagascar (from 82 % to 99.5 % between 1992 and 2000, for practically the same equipped areas) and Tunisia (from 84 % in 1991 to 99.7 % to 2000, for increased equipped areas). Conversely, three nations have experienced a reduction in the use of their irrigation systems. In Lesotho, the area actually irrigated declined from 7 % of equipped areas in 1994 to 3 % between in 1999, for the same equipped areas. In Mozambique the use rate fell from 42 % to 34 % between 1995 and 2001, for a slight increase in equipped area. While a additional extensive use of equipped areas in the initial group of nations 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 nations. Finally, part those nations with a current use rate of less than 50 %, the Sudan has experienced considerable degradation, with the area actually irrigated declining from 63 % in 1995 to 43 % in 2000.

Water management

Water management in African nations is generally based on a water code. Thirty-seven nations have such a code for governing in a world way the management of water resources present on their territory. Three other nations (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 nations (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 nations (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 data was available for two humid nations, 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 nations 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 from presently on approved its water law drafted in 1996. Finally, legislation focusing additional 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 nations: 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 nations (41 out of 53), departments or divisions within the Ministry of Agriculture or within the Ministry of Agriculture and Irrigation or Water Resources. However, the management and conservation of water resources are generally the responsibility of an extra 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 nations 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 nations have a Ministry of Water Resources that includes irrigation management: Algeria, Egypt, Kenya and Nigeria, which account for 43 % 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 National, 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 National from the irrigation sector since the 1980s, and the subsequent creation of users associations that are by presently in place or planned (South Africa, Burundi, Côte d’Ivoire, Ghana, Madagascar, Mali, Morocco, Mauritius, Niger, Nigeria, Senegal, Sudan, Swaziland, Tunisia and Zimbabwe), inclunding the additional recent promotion of participatory approaches (Burkina Faso, Mauritania and Chad) concerns about 20 African nations. 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 National. 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 significant. 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 nations because of the difficulty in obtaining data. Its increase and development are explained by the disengagement of the National in the irrigation sector and the development of private irrigation. It is generally carried out on a small scale, but represents a significant added price for each of the farmers in terms of gain. It is difficult to estimate this type of irrigation on a continental scale.

Water tariffication is used in only 27 nations, 23 of which envisage charges, mainly based on irrigated area. In nine nations, 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.

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