Although flooding along the Nile River in the African
country of Sudan is an annual event, this years river
levels are the highest in more than 20 years. About 70,000 acres of farmland have been inundated by the rising river,
displacing roughly 7,000 families from their homes. Downstream in Egypt,
public works officials are confident that the the run-off canals behind the Aswan High Dam can carry enough water to
avert flooding in their country. Several years of above-average
rainfall along the Nile River have already created several
new lakes in Egypt.
The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), the zoom lens aboard NASAs Terra satellite,
acquired this high-resolution view of the Sudanese capital of Khartoum and flooded
farmland along the Nile on August 30, 2001. The pseudo true-color image
is a combination of near-infrared and visible light data which simulates a photograph
taken from space. The city of Khartoum is at the lower right, at the confluence
of the White (left) and Blue (right) Nile Rivers. Flooded farmland along the banks
of the Nile appears dark blue. The two inset images show the flooding at a spatial resolution of 15 meters per pixel--ASTERs full resolution. The surrounding desert is colored pink.
Flooding is a particularly severe problem in this region because most
human settlements are along rivers. An earlier sequence of images from the
Multi-angle Imaging Spectroradiometer (MISR), another instrument aboard Terra,
shows seasonal fluctuation of the Nile.
Sudan’s capital city, Khartoum, translates as “Elephant’s Trunk.” The name describes the shape of the Nile where the Blue and the White Nile Rivers unite to form the single Nile River that flows northward into Egypt. This image shows the rivers near the end of the dry season. The White Nile (western branch) runs through Sudan from Uganda. It originates in equatorial regions, where rainfall occurs throughout the year, and as a result it runs at a nearly constant rate throughout the year. The Blue Nile, nearly dry this time of year, flows out of the Ethiopian highlands, where rainfall is more seasonal. It swells in the late summer and early fall with rains from the summer monsoons. The flow at these times can be so great that the volume is too much for the river’s channel, causing the Nile to flow backward at the junction.