Inland delta of the Niger River
Apart from the delta of the Nile River, the inland delta of the Niger River may be Africa's most famous. Astronauts aboard the International Space Station took this photograph on 17 October 2014 of the region where the Niger and other rivers flow out of the wetter, more vegetated Sahel into the Sahara Desert. The rivers inundate the lush green wetland of the delta.
For millennia, the river has been the most important water supply in the western Sahara Desert. After tracing an irregular path through a series of linear dunes, the river makes its way to the ancient city of Timbuktu and many other cities further downstream. Even the arrow-shaped, 100-kilometre (60 mile) depression known as Lake Faguibine-scoured out by desert winds to levels a few metres below the Niger Delta-is still regularly flooded by water from the Niger. This allows crops to be grown on the lake floor as the water recedes.
In the millions of years that the Niger has brought water and sediment into the desert, the delta has repeatedly changed. The remnant of an older delta can still be seen, especially where flows from the Niger make a smaller wetland near the left edge of the image.
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Credit: NASA Earth Observatory