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.
Western Darfur stands in stark 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 (see
Glossary), 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
(see Glossary), 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--see Glossary) 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
(see Glossary), the land between the Blue Nile and the White Nile
(literally in Arabic "peninsula") where the great Gezira Scheme
(also seen as 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. 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 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 midnineteenth 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 the watershed are the 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 stark contrast to the great plains to the
north that dominate Sudan's geography.
Data as of June 1991