Wetland Management
By
Dr. Elfatih Eltagi Mahgoub and Dr. Khalid M. Riak
Introduction:
The Republic of Sudan, is the largest country in Africa and is located between latitudes 030 31” and 220 00” N with an area of 2,205,815 km2 . Due to the wide latitudinal range, different parts of the country experience very different climates and thus, various wetland ecosyetms are found. Rainfall increases gradually as one move from north to south of the country. That is, from negligible in the desert in the north to a maximum of 1,000-1,200 mm annually in the southern border and up to 1,500 mm in the Imatong mountains. The red sea coastal plain receives rainfall in winter while the rest of the country experiences rainfall from March to November.
The topography of the country is characterized by a vast interior plains with an average altitude of 500-1,000 m. On the western side of the Sudan lies the Jebel Marra massif which reaches 3,071 m. above sea level. Mount Kinyeti, in the Imatong mountains is at 3.187 m, which makes it the highest point in the Sudan. The Nuba mountains, which reach 1,300 m, lie in Kordofan in central Sudan, while in the south-west there is an area of upland which marks the watershed between the Nile and the Congo river systems.
The Nile river system is the main topopgraphical feature of the country. The White Nile (Bahr-el-jebel) enters the Sudan near the town of Nimule on the Ugandan border. North of Bor, the river, due to the almost flat topography, slows and spreads to seasonally occupy an enormous area of papyrus-dominated swampland, known as As Sudd, which extends northwards for about 350 km. Near the northern limit of As Sudd, close to the town of Malakal, the White Nile is joined by two large tributaries, the Sobat from the east and the Bahr-el-Ghazal from the west. From that point the river flows north to Khartoum, which marks the confluence of the White Nile with the Blue Nile, flowing northwestward from the Ethiopian highlands. Another large tributary the Atbra, joins the system at the town of Atbra whence the Nile flows through the Sahara to reach the Egyptian border at Wadi Halfa.
The information about wetlands in the county are very rare and therefore the aim of this paper is to review the presnt status of wetlands in the country and propose some recommendations pretaining to their mamagement and conseravtion and sustainable utilization for the benefit of the Sudanese people.
Wetlands Ecosystem in Sudan:
Wetlands are defined as areas of marsh, fen, peat land or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six meters (Ramsar Convention 1971). Thus, under this definition different habitat types are considered as wetlands and these include seasonal rivers, khores, natural and man-made lakes, coastal lagoons, mangroves, swamps, coral reefs, mayas (seasonal inundated mudflat in river channels), flood plains, haffirs and reservoirs.
Wetlands play a vital hydrological and ecological role in the Sudan. They trap and slow seasonal floods, dampening the magnitude of floods downstream and spreading out peak flows over several weeks or months. The delay and extension of flood peaks can facilitate downstream fishing and irrigation, especially in areas with an extended dry season.
Wetlands provide habitat for numerous species of animals and plants, many of them unique to these ecosystems.
Those wetlands which are near the edge of the Sahara provide vital staging grounds for migratory birds preparing to cross the desert. Wetlands also trap and hold silt carried by rivers, creating fertile alluvial soils that may be used to grow many crops and vegetables.
However, agricultural development schemes, taking advantage of the presence of both fertile soil and water, pose a threat to many wetlands.
Freshwater marshes, such as the huge As Sudd in Sudan, are dominated by herbaceous species such as papyrus, supports a rich indigenous flora and fauna, and attracts huge numbers of migratory wildlife during the dry season. Like many others, this vital and sensitive wetland ecosystem is threatened by the growth of ranching and tourism, and by proposals to divert water for irrigation and other uses.
Wetlands cover 20% of the total area of the country. Based on the Ramsar definition and according to Morghraby ( 2001) there are about 13 wetlands types distinigusted in the country which include the following:-
o Large Swamps (As Sudd)
o Seasonal Streams ( e.g. Gash, Barraka, Dinder & Rahad)
o Nile & its tributaries
o Mountain Streams (e.g. Khor Arba’at, River Gilo & Ingassana Hills)
o Lakes
o Man-made lake system
o Dams
o Hot springs
o Haffirs
o Mayas
o Coral reef
o Mangrove Swamps (red sea coast)
LARGER SWAMPS:
As Sudd (Bahr-el-jebel system):
As Sudd swamp of southern Sudan is among the largest and most important wetlands in Africa. Three protected areas exist within As Sudd, these are Shambe National Park, Fanyikang and Zeraf Game Reserves. They all fall within the Bahr-el-jebel system of As Sudd, the part of the swamps that will be most affected by the Jonglei canal.
As Sudd swamp is the seasonally inundated flood-plain of the upper White Nile. It is divid into four distinct sections, of which the Bahr-el-Jebel is the centeral system and thought to be the most important for wildlife. The other sections are the Bahr-el-Ghazal system to the west, the Sobat-Baro-Pibor river system to the east and the smaller Machar Marshes to the north-east. The Bahr-el-jebel system consists of two main rivers, the Bahr-el-jebel, the main course of the White Nile, to the west and the smaller Bahr-ez-Zeraf to the east. The area is extremely flat with an average slope of only 10 cm per km.
As Sudd swamp consists of a variety of wetlands, grasslands and woodlands. The wetland comprises flowing waters, lakes and permanent swamps. There are three swamp types: Vossia cuspidat swamps (which cover 250 km2), Cyperus papyrus swamps (3,900 km2) and Typha domingensis swamps (13,600 km2).
The seasonally inundated grassland is known as “toich” where the period of annual inundation is long enough to inhibit tree growth but not long enough to maintain permanent swamp conditions. The seasonally inundated grassland is divided into seasonally river-fiooded grassland (16,200 km2) and seasonally rain-flooded grassland (20,000 km2).
There are areas of single-species woodland mainly of Acacia seyal (5,400 km2) or Balanites aegytiaca (5,300 km2). Mixed woodland is characterized by Ziziphus mauritiana, Combretum fragrans, Acacia seyal and Balanites aegyptiaca. Average annual precipitation in the area is c.900 mm and falls from late April to November.
As Sudd swamps holds a large population of shoebill stork Balaeniceps rex. Aerial surveys in 1979-1982 counted a peak of 6,407. It is also an important site for white-eyed pochard Aythya nyroca, and on passage, for lesser kesterl Falco naumanni.
Mammals of global conservation concern include Loxodonta africana, Panthera leo, Lycaon pictus, Acinonyx jubatus, Damaliscus lunatus, Syncerus caffer, Hippotragus equinus, Giraffa camelopardalis, Redunca redunca, Gazella thomsonii, and Alcelaphus buselaphus.
Excessive amounts of water are lost in As Sudd by evapotranspiration. To increase the flow of water downstream, principally to provide more water to Egypt, a diversion channel, Jonglei, was proposed. Jonglei canal extends for 360 km in an almost direct line from Bor to Malakal. The construction of the canal started in 1978 but it was brought to a halt in 1983 by the civil war in southern Sudan.
As Sudd is inhabited by the Neur, Dinka and Shilluk tribes. These tribes are agropastoralists, they raise cattle, sheep and goats which are estimated at one million. The local inhabitant also depend on As Sudd swamps for agriculture. They grow food crops such as sorghum, maize, yam and cash crops such as ground nuts, sesame and tobacco. Crop yields are low due to the heavy impermeable low nutrient nature of the soil. Small fishing communities are widely scattered within As Sudd. During the dry season the populations of the large wild animals and the livestock concentrate on the comparatively small areas of a relatively high ground.
SEASONAL STREAMS AND NILE TRIBUTARIES:
These types of wetlands are numerous in the country and are characterised by their fast flowing, silt laden waters. They preform various functions including nutrients transport to large water bodies, important breeding grounds for both fishes, reptiles and water sources for wildlife and domestic livestock. The flora of these wetlands are influenced by the intensity of rainfall (Morghraby, 2001). The largest and most known seasonal streams in the country include Gash, Baraka, Rahad and Dinder
Dinder National Park:
The Dinder National Park (DNP) is located in southeastern Sudan near the Ethiopian border. It consists of low lying flood plains with a few rocky hills on the southern corner. The Rahad and Dinder rivers flow north-westwards forming pools and ox-bow lakes known as mayas. Mayas are important wetlands in the park as they constitute the main source of food and water for wildlife during the dry season which extends from November to June.
Dinder National Park ( 650,000 ha ) was established in 1935 and extended to include a buffer zone ( 277,300 ha ) in 1980. This extension resulted in the inclusion of twelve villages to the park. The park was designated as a biosphere reserve in 1979. The Rahad Game Reserve (350,000 ha) adjoining the park, was abolished by a presidential decree in 1992 and the land was allocated for agricultural, forestry and grazing activities at the ratios of 50%, 40% and10% respectively ( kenyi. 2001 ) .
Wildfires, set by herdsmen, honey gatherers and poachers affects up to 60% of the park. Areas around the park are degraded as a result of mechanized farming and removal of the tree cover. Hunting pressure is high, giraffes disappeared from the park in 1985 and tiang suffered from considerable reduction in its numbers. Livestock grazing within the park not only causes competition with wildlife for food and water, but also causes outbreaks of rinderpest particularly among buffloes and tiang.
Radom National Park:
Radom National Park is located in the southwestern corner of Southern Darfur on the border with Central African Republic. It consists of an area of brocken hilly country lying between two main rivers, the Adda and the Umbelasha, which form the park’s northern and southern boundaries respectively. These hills are part of the range which forms the watershed that separates the Nile and Congo river systems. The vegetation is principally savanna woodland dominated by Terminalia brownii, Combretum spp., Anogeissus leiocarpus and Isoberlinia doka. Wet meadows (dahls) form in low-lying basins and hold water into the dry season, providing water and fodder. Average annual precipitation ranges from 630 mm in the north to 900 mm in the south. Radom National Park is contiguous with the reserve complex of the Parc Nationale d’Andre’ Felix in the Central African Republic.
There is meagre information about wildlife in the park. Mammals of global conservation concern include: Loxodonta africana, Panthera leo, Lycaon pictus, Acinonyx jubatus, Giraffa camelopardalis, Kobus ellipsiprymnus and K. kob.
Radom was declared as a biosphere reserve in 1979. There are many villages inside the park. The increasing human populations within and in the periphery of the park leads to an increase of human activity such as cultivation, tree felling and grazing.
MOUNTAIN STREAMS:
These wetland types are mainly found in the Eastern, Southern and Southeastern Sudan. The examples are Khor Arba’at, River Gilo and Ingasana hills repectively. All these wetlands are rich in term of biodiversity. Imatong, Khor Arbat and Boma are briefly discussed and given as examples of protected mountain wetlands.
Imatong mountains:
The Imatong central forest reserve is located south-east of Juba on the Ugandan border. The Imatong mountains are deeply faulted with many perennial rivers within their upland regions. They are covered by a range of vegetation types including Albizi- Terminalia woodland and mixed Khaya lowland semi-evergreen forest up to 1,000 m, and by Podocarpus and Croton-Macaranga-Albizia montane forest at 1,000-2,900 m. At higher altitude the forest is replaced by Hagenia woodland, Erica thicket and areas of bamboo. The Imatong mountains, due to their wide altitudinal range and location at the meeting point of several biomes, support high spescies diversity.
Khor Arba’at:
Khor Arba’at is located 15 Km inland, immediately east of the Red Sea Hills, and about 25 Km north–west of Port Sudan. It is the main source of drinking water to the city. A pumping station has been constructed on what has become an artificial island, surrounded by the only permanent water in the Red Sea Hills. The surrounding desert which, apart from a few scattered bushes along the riverbed, is largely barren.
Khor Arba’at is important for a wide diversity of palearctic migrant such as Acrocephalus palustris, Crex crex, Acrocephalus griseldis and Emberiza cineracea. A large number of birds have been reported killed by the overhead powerlines which supply the station’s electric water pump.
Boma:
It includes Boma National Park and the adjacent Boma hills. The area is located in the south-east of Sudan close to the Ethiopian border, south-east of the town of Pibor Post. Two-thirds of the park is flat flood-plain, punctuated by a number of isolated hills, rising to undulating terrain in the east to reach the Boma plateau at about 1,100 m. In the south-east the Boma hills rise above the plateau and drained eastwards into the Oboth and Akobo rivers and thence eventually into the Guom swamps. The western part of the park drains into the Kangen river. The western plains support open grassland of Hyparrhenia, Pennisetum, Sporobolus and Echinochloa spp., while the eastern parts are covered with woodland dominated by Combretum and Ficus species. Areas of dense thickets dominated by Ziziphus spp., Acacia seyal,