Geography of Sudan - Geographical Regions

Geographical Regions

Northern Sudan, lying between the Egyptian border and Khartoum, has two distinct parts, the desert and the Nile Valley. To the east of the Nile lies the Nubian Desert; to the west, the Libyan Desert. They are similar—stony, with sandy dunes drifting over the landscape. There is virtually no rainfall in these deserts, and in the Nubian Desert there are no oases. In the west, there are a few small watering holes, such as Bir an Natrun, where the water table reaches the surface to form wells that provide water for nomads, caravans, and administrative patrols, although insufficient to support an oasis and inadequate to provide for a settled population. Flowing through the desert is the Nile Valley, whose alluvial strip of habitable land is no more than two kilometers wide and whose productivity depends on the annual flood.

Western Sudan is a generic term describing the regions known as Darfur and Kurdufan that comprise 850,000 square kilometers. Traditionally, this has been regarded as a single regional unit despite the physical differences. The dominant feature throughout this immense area is the absence of perennial streams; thus, people and animals must remain within reach of permanent wells. Consequently, the population is sparse and unevenly distributed. Western Darfur is an undulating plain dominated by the volcanic massif of Jabal Marrah towering 900 meters above the Sudanic plain; the drainage from Jabal Marrah onto the plain can support a settled population and a variety of wildlife (see East Saharan montane xeric woodlands). Western Darfur stands in contrast to northern and eastern Darfur, which are semidesert with little water either from the intermittent streams known as wadis or from wells that normally go dry during the winter months. Northwest of Darfur and continuing into Chad lies the unusual region called the jizzu, where sporadic winter rains generated from the Mediterranean frequently provide excellent grazing into January or even February. The southern region of western Sudan is known as the qoz, a land of sand dunes that in the rainy season is characterized by a rolling mantle of grass and has more reliable sources of water with its bore holes and hafri (sing., hafr) than does the north. A unique feature of western Sudan is the Nuba mountain range of southeast Kurdufan in the center of the country, a conglomerate of isolated dome-shaped, sugarloaf hills that ascend steeply and abruptly from the great Sudanic plain. Many hills are isolated and extend only a few square kilometers, but there are several large hill masses with internal valleys that cut through the mountains high above the plain.

Sudan's third distinct region is the central clay plains that stretch eastward from the Nuba Mountains to the Ethiopian frontier, broken only by the Ingessana Hills, and from Khartoum in the north to the far reaches of southern Sudan. Between the Dindar and the Rahad rivers, a low ridge slopes down from the Ethiopian highlands to break the endless skyline of the plains, and the occasional hill stands out in stark relief. The central clay plains provide the backbone of Sudan's economy because they are productive where settlements cluster around available water. Furthermore, in the heartland of the central clay plains lies the jazirah, the land between the Blue Nile and the White Nile (literally in Arabic "peninsula") where the great Gezira Scheme (aka Jazirah Scheme) was developed. This project grows cotton for export and has traditionally produced more than half of Sudan's revenue and export earnings.

Northeast of the central clay plains lies eastern Sudan, which is divided between desert and semidesert and includes Al Butanah, the Qash Delta, the Red Sea Hills, and the coastal plain. Al Butanah is an undulating land between Khartoum and Kassala that provides good grazing for cattle, sheep, and goats. East of Al Butanah is a peculiar geological formation known as the Qash Delta. Originally a depression, it has been filled with sand and silt brought down by the flash floods of the Qash River, creating a delta above the surrounding plain. Extending 100 kilometers north of Kassala, the whole area watered by the Qash is a rich grassland with bountiful cultivation long after the river has spent its waters on the surface of its delta. Trees and bushes provide grazing for the camels from the north, and the rich moist soil provides an abundance of food crops and cotton.

Northward beyond the Qash lie the more formidable Red Sea Hills. Dry, bleak, and cooler than the surrounding land, particularly in the heat of the Sudan summer, they stretch northward into Egypt, a jumbled mass of hills where life is hard and unpredictable for the hardy Beja inhabitants. Below the hills sprawls the coastal plain of the Red Sea, varying in width from about fifty-six kilometers in the south near Tawkar to about twenty-four kilometers near the Egyptian frontier. The coastal plain is dry and barren. It consists of rocks, and the seaward side is thick with coral reefs.

The southern clay plains, which can be regarded as an extension of the northern clay plains, extend all the way from northern Sudan to the mountains on the Sudan-Uganda frontier, and in the west from the borders of Central African Republic eastward to the Ethiopian highlands. The plain is covered with swathes of savanna grassland running east to west which have different characteristics depending on the amount of rainfall they receive. These are Sahelian Acacia savanna in the north and East Sudanian savanna to the south. This great Nilotic plain is broken by several distinctive features. First, the White Nile bisects the plain and provides large permanent water surfaces such as lakes Fajarial, No, and Shambe. Second, As Sudd ("The Sudd"), the world's largest swamp, provides a formidable expanse of lakes, lagoons, and aquatic plants, whose area in high flood waters exceeds 30,000 square kilometers, or approximately the size of Belgium. So intractable was this sudd (see Glossary) as an obstacle to navigation that a passage was not discovered until the mid-nineteenth century. Then as now, As Sudd with its extreme rate of evaporation consumes on average more than half the waters that come down the White Nile from the equatorial lakes. These waters also create a flood plain known as the toic that provides grazing when the flood waters retreat to the permanent swamp and sluggish river, the Bahr al Jabal, as the White Nile is called here.

The land rising to the south and west of the southern clay plain is referred to as the Ironstone Plateau (Jabal Hadid), a name derived from its laterite soils and increasing elevation. The plateau rises from the west bank of the Nile, sloping gradually upward to the Congo-Nile watershed. The land is well watered, providing rich cultivation, but the streams and rivers that come down from the watershed divide and erode the land before flowing on to the Nilotic plain flow into in As Sudd. Along the streams of this Northern Congolian forest-savanna mosaic are gallery forests, the beginnings of the tropical rain forests that extend far into Zaire. To the east of the Jabal Hadid and the Bahr al Jabal rise the foothills of the mountain ranges along the Sudan-Uganda border — the Imatong, Didinga, and Dongotona — which rise to more than 3,000 meters. These mountains form a contrast to the great plains to the north that dominate Sudan's geography.

Sudan includes islands located in the Nile (including Aba Island, Badien Island, Sai Island, and, at the confluence of the Blue and White Nile, Tuti Island) and in the Red Sea (including the Suakin Archipelago).