Geography of Sudan
[1] 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.
[1] The dominant feature throughout this immense area is the absence of perennial streams; thus, people and animals must remain within reach of permanent wells.
[1] 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.
[1] 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.
[1] Between the Dindar and the Rahad rivers, a low ridge slopes down from the Ethiopian highlands contrasting the neighboring plains as do the occasional hills.
[1] The central clay plains provide the backbone of Sudan's economy because of the large amounts of settlements which are there due to the available water.
[1] 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.
[1] Dry, bleak, and cooler than the surrounding land, particularly in the heat of the Sudanese summer, they stretch northward into Egypt, a jumbled mass of hills where life is hard and unpredictable for the Beja inhabitants.
[5] West of the White Nile, these soils are used by traditional cultivators to grow sorghum, sesame, peanuts, and (in the area around the Nuba Mountains) cotton.
[5] Though livestock raising is this area's major activity, a significant amount of crop cultivation, mainly of pearl millet, also occurs.
[6] The White Nile flows north from Central Africa, draining Lake Victoria and highland regions of Uganda, Rwanda, and Burundi.
[6] North of Khartoum, the Nile flows through the desert in a large S-shaped pattern to empty into Lake Nasser behind the Aswan High Dam in Egypt.
[8] There is minimal rainfall countrywide except for a small area in northwestern Sudan where the winds have passed over the Mediterranean bringing occasional light rains.
[8] In September the dry northeasterlies begin to strengthen and to push south and by the end of December they cover the entire country.
[8] Northern Sudan, with its short rainy season, has very high daytime temperatures year round, except for winter months in the northwest where there is some precipitation in January and February.
[8] Conditions in highland areas are generally cooler, and the hot daytime temperatures during the dry season throughout central and northern Sudan fall rapidly after sunset.
[8] The haboob, a violent dust storm, can occur in central Sudan when the moist southwesterly flow first arrives (May through July).
[8] The initial downflow of air from an approaching storm produces a huge yellow/red wall of sand and clay that can temporarily reduce visibility to zero.
[citation needed] Areas around Wadi Halfa and along the Egyptian border can easily pass many years or many decades without seeing any rainfall at all.
[6] Desertification, the southward shift of the boundary between desert and sem-idesert, has occurred at an estimated rate of 50 to 200 kilometers since records of rainfall and vegetation began in the 1930s.
[6] Sudan as a whole might have lost nearly 12 percent of its forest cover between 1990 and 2005, or about 8.8 million hectares, a loss driven primarily by land clearance and energy needs.
[6] Compounding Sudan’s environmental problems are long years of warfare and the resultant camps for large numbers of internally displaced people, who scour the surrounding land for water, fuel, and food.
[6] Experts from the United Nations predict that Sudan’s current program of dam construction on the Nile and its tributaries will cause riverbank erosion and loss of fertilizing silt.
[6] In urban areas, rapid and uncontrolled population influx into Khartoum and other cities and towns and the general lack of facilities to manage solid waste and sewage are among major environmental concerns.
