| FishBase | Complete | Literature | Reference | |||
|---|---|---|---|---|---|---|
| Species | Families | Species | Families | |||
| Marine | 350 | 86 | No | |||
| Freshwater | 129 | 30 | No | Daget, J., J.-P. Gosse and D.F.E. Thys van den Audenaerde, 1984 | ||
| Total | 491 | 116 | No | |||
| Conservation | The following information is to be sought: - Status of knowledge of the freshwater fauna; - Existence of conservation plans; - Information on major aquatic habitats or sites within the country; - Current major threats to species; - Future potential threats to species; - Contact(s) for further information. |
| Geography and Climate |
Sudan (with an area of 2,476,800 sq. km.) is a flat country with elevated lands to the east, south and southwest. Vegetation patterns change from tropical forest in the south through semi-tropical savanna to sandy arid hills in the north. Extreme desert conditions prevail in the northwest. The central zone of the country is transected by the Nile Valley with its large swamp depression in the Sudd.
The north of the country has a desertic climate with little rainfall throughout the year. The centre of the country has an unstable climate, with a pronounced rainy season of variable duration. In the south the climate is equatorial, with more or less daily rainfall.
Sudan is mainly a desertic country; there is, therefore, a very high demand for water. The several reservoirs are for flow retention associated with irrigation areas. The Jonglei Canal will allow about 10% of the present Nile flow to bypass the Sudd Swamps to increase the amount of water available for irrigation downstream. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |
| Hydrography |
The freshwater resources of the Sudan have been comprehensively reviewed by CSTR (1982) (Ref. 12127). Dumon (1984) (Ref. 12128) presents the most recent series of papers on limnology and marine biology. This text summarizes some of that data. According to OSRO (1986), (Ref. 12129), nearly 12.90 million hectares are under water, 5% of the total area in the Sudan. Of the available water, less than 50% is used, and the potential water supply is enormous if underground reserves are included. The Nile system is the main feature of the hydrology of Sudan, including the Nile and its tributaries, a number of man-made lakes and the swamps of the Sudd. Non-Nilotic streams of minor importance supply water to 806 hafirs (natural depressions enlarged into small ponds) and 31 dams.
Lakes: the principal natural lakes in the country are the numerous small floodplain lakes, most important of which is Lake No, which concentrates the major part of the flow from the Nile as it emerges from the Sudd. A few smaller isolated lakes also occur (Welcomme, 1979) (Ref. 12130).
Rivers, floodplains and swamps: the main river system is that of the Nile. The Albert Nile enters Sudan from Uganda through a narrow gorge in a series of rapids at Nimule. Northward, it becomes known as the Bahr El Jebel which flows into the great swamps of southern Sudan, North of Mangola. The main tributary of the Bahr El Jebel is the Aswa, originating from the Marolo mountain on the Kenyan border. The river widens to several kilometers and divides into the Bahr El Jebel and Bahr El Zeraf in the Sudd Region. There the rivers have numerous channels and follow a serpentine course, to be joined by the Bahr El Ghazal, which drains the southwest part of Sudan, forming the White Nile. South of Malakal, the Sobat River of a catchment area of 224,000 sq. km. consisting of the Baro and Pibar tributaries, joins the While Nile. From here northward the valley is steep sided until it joins the Blue Nile at Khartoum.
The Blue Nile, with a catchment of 325,000 sq. km., originates in Ethiopia and extends 2,000 km until it joins the White Nile to become the River Nile. Within Sudan the Blue Nile is joined by the Dinder and Rabad tributaries. The main Nile passes the Sabaloka Gorge and is joined by the Atbara, a catchment of 100,000 sq. km. and main tributary Sesit. Thereafter, there are two further cataracts before the Nile leaves Sudan at Lake Nubia.
Reservoirs: a number of major reservoirs have been built or are proposed for the Nile system, mainly for irrigation water storage. Conditions require some form of water storage for the dry period. Natural depressions were enlarged into small ponds of up to 500,000 cu. m., deep; these are known as "hafirs".
Coastal lagoons: there are no lagoons of significant size. Ref. Vanden Bossche, J.-P. and G.M. Bernacsek, 1990 |