GEOGRAPHY AND POPULATION
Mauritania, located in the north-west of the African continent, has a total area of about 1 million km². It is bordered in the north-west by Western Sahara, in the north-east by Algeria, in the east and south-east by Mali, in the south-west by Senegal and in the west by the Atlantic Ocean.
The cultivable area has been estimated at about 20 million ha, or almost 20% of the total area. In 1989, the total cultivated area was 204 000 ha, of which 199 000 ha consisted of annual crops and about 5 000 ha consisted of permanent crops.
The total population is about 2.3 million (1995), of which 46% is rural. The population density is about 2 inhabitants/km², but this figure varies from 0.1 in Tiris Zemrnour to 18.5 in the Gorgol region. The annual demographic growth rate is about 2.7%. Agriculture, including livestock, accounts for 20% of GDP.
TABLE 1 - Basic statistics and population
|Area of the country||1995||102552000||ha|
|Cultivable area||1985||20 129 689||ha|
|- annual crops||1989||199 000||ha|
|- permanent crops||1994||5 000||ha|
|Total population||1995||2 274 000||inhabitants|
|Water supply coverage:|
CLIMATE AND WATER RESOURCES
Average annual rainfall is 99 mm, but this varies from less than 20 mm in the north to more than 500 mm in the south-east (Sélibaby). The rainy season lasts only 3 months. Average minimum and maximum temperature vary from 16°C in January (Bir Mougrein) to 36°C in June (Kiffa).
The total (actual) renewable surface water resources are estimated at 11.1 km³/year and the internal renewable surface water resources at 0.1 km³/year. The hydrographic system is dominated by the Senegal river which runs along the southern border and its tributaries on the right bank downstream of Bakel. There are some wadis with sporadic flows during the rainy season. Total groundwater resources have been estimated at 3.7 km³, which refers to the continuous aquifers only. The yields of the alluvial groundwater in the wadis and the intermittent aquifer systems have not yet been quantified. Internal renewable groundwater resources are estimated at 0.3 km³/year.
TABLE 2 - Water: sources and use
|Renewable water resources:|
|Internal renewable water resources||0.4||km³/yr|
|Total (actual) renewable water resources||1995||11.4||km³/yr|
|Total (actual) renewable water resources per inhabitant||1995||5 013||m³/yr|
|Total dam capacity||1994||900||106 m³|
|-agricultural||1985||1 500||106 m³/yr|
|Total water withdrawal||1 630||106m³/yr|
|as % of total (actual) renewable water resources||14.3||%|
|Other water withdrawal||-||106m³/yr|
|Average groundwater depletion||-||106m³/yr|
|Wastewater - Non-conventional water sources:|
|- produced wastewater||-||106m³/yr|
|- treated wastewater||-||106m³/yr|
|- reused treated wastewater||-||106m³/yr|
Figure 1 - Water withdrawal (total: 1.63 km³ in 1985)
Figure 2 - Distribution of the water managed areas (total: 113 200 ha in 1994)
In 1985, total water withdrawal was 1.63 km³, of which 92 % for agricultural purposes (figure 1).
It is estimated, that in the year 2000 about 3 750 water points will be needed to supply drinking water to the rural population, while at present 2 118 water points have been constructed.
IRRIGATION AND DRAINAGE DEVELOPMENT
Irrigation potential, considering soil resources, has been estimated at 257 000 ha, of which 110000 ha for flood recession cropping. Considering the available water resources as well, the irrigation potential in the Senegal basin is estimated at 165 000 ha, of which 125 000 ha along the main Senegal river and 40 000 ha in the Gorgol and Karakoro tributary areas. In addition, there are around 5 000 ha of oases.
TABLE 3 - Irrigation and drainage
|Irrigation potential||1994||170 000||ha|
|1. Full or partial control irrigation: equipped area||1994||49 200||ha|
|- surface irrigation||-||ha|
|- sprinkler irrigation||-||ha|
|% of area irrigated from groundwater||1994||9.6||%|
|% of area irrigated from surface water||1994||90.4||%|
|% of area irrigated from non-conventional sources||1994||0.0||%|
|% of equipped area actually irrigated||1994||54.4||%|
|2. Spate irrigation area||-||ha|
|3. Equipped wetland and inland valley bottoms (i.v.b.)||-||ha|
|Total irrigation (1 +2+3)||1994||49 200||ha|
|- as % of cultivated area||24||%|
|4. Flood recession cropping area||1988||64 000||ha|
|Total water managed area (1 +2+3+4)||1994||113 200||ha|
|- as % of cultivated area||55||%|
|- increase over last 10 years||-||%|
|- power irrigated area as % of water managed area||1994||41.6||%|
|Full or partial control irrigation schemes: Criteria|
|Large-scale schemes > 200 ha||1994||6217||ha|
|Medium-scale schemes||1994||3 037||ha|
|Small-scale schemes < 50 ha||1994||39 967||ha|
|Total number of households in irrigation|
|Total irrigated grain production||1993||136 498||tons|
|as % of total grain production||1993||66||%|
|Harvested crops under irrigation (full or partial control)||1993||134 899||ha|
|- permanent crops: total||1993||4 751||ha|
|- annual crops: total||1993||130 148||ha|
|. sorghum||1993||62 488||ha|
|. vegetables/polyculture||1993||40 820||ha|
|. rice||1993||22 408||ha|
|. other annual crops (maize)||1993||4 432||ha|
|Drainage - Environment:|
|Drained area||1994||12 784||ha|
|as % of cultivated area||6||%|
|- drained areas in full or partial control irrigated areas||-||ha|
|- drained areas in equipped wetland and i.v.b||-||ha|
|- other drained areas||-||ha|
|- total drained area with subsurface drains||-||ha|
|- total drained area with surface drains||-||ha|
|Area salinized by irrigation||-||ha|
|Population affected by water-borne diseases||-||inhabitants|
In 1994, the water managed area was evaluated at 113 200 ha, of which 49 200 ha consisted of full or partial control irrigation schemes. Flood recession cropping covered the remaining 64 000 ha (Figure 2).
The area equipped for full or partial control irrigation consists mainly of small schemes, with an area of less than 50 ha each (Figure 3). The total area can be divided into 4 571 ha of oases and 44 629 ha of schemes in the provinces of the valley of the Senegal river and its tributaries (Figure 4)
Figure 3 - Typology of f/p control irrigation schemes (total: 49 200 ha in 1994)
Figure 4 - Distribution of the f/p control irrigation schemes (total: 49 200 ha in 1994)
Figure 5 - Methods of groundwater extraction in the oases (total: 4 751 ha in 1993)
Figure 6 - Typology of oases (total: 4 751 ha in 1993)
Figure 7 - Origin of irrigation water f/p (total: 49 200 ha in 1994)
Figure 8 - Typology of flood recession cropping (total: 64 000 ha in 1988)
Figure 9 - Irrigated crops (total: 134 899 ha in 1993)
The main irrigation technique used in the full or partial control irrigation schemes is surface irrigation. The average cost of irrigation development varies between $US 2 200/ha for small schemes to about $US 12 500/ha for large schemes.
Different types of flood recession cropping can be distinguished (Figure 8):
The major irrigated crops are sorghum, vegetables and rice. Palm trees grow in the oases. Mixed farming, with vegetable growing is important in the flood recession zones (Figure 9).
The public institutions intervening in hydraulic and agricultural development are:
The Ministry of Rural Development and Environment:
The Ministry of Hydraulics:
Decree No 90020 of 19 January 1990 establishes the clauses of the reorganization of the land properties, putting the accent on the individualization of land tenure, in three phases: authorization to cultivate, provisional concession and permanent concession.
TRENDS IN WATER RESOURCES MANAGEMENT
The major constraints to the exploitation of the water resources and the development of irrigation in Mauritania can be summarized as follows:
MAIN SOURCES OF INFORMATION
Cellule de planification, Ministère du développement rural et de ltenvironnement. 1994. Le développement rural en chiffres.
FAO/DDC. 1988. Programme national de construction des barrages en terre.
FAO/DDC. 1990. Projet de développement intégré de la vallée du fleuve Senegal. Document de travail (voles irrigation).
GERSAR. 1994. Etudes d'application des schémas directeurs du fleuve Sénégal et du Delta.
Ministère du développement rural et de l'environnement. 1993. Annuaire statistique des oasis.
PNUD. 1990. Schema directeur pour la mise en valeur des ressources en eau. Rapport du projet PNUD/DTCD/MAU/87/008.
SONADER. 1993. Enquête périmètres irrigués.
SONADER. 1994. Rapport d'activités 1993.