Geography of the Sahara Desert
The Sahara covers parts of several African nations including Algeria, Chad, Egypt, Libya, Mali, Mauritania, Morocco, Niger, Sudan and Tunisia. Most of the Sahara Desert is undeveloped and features a varied topography. Most of its landscape has been shaped over time by wind and includes sand dunes, sand seas called ergs, barren stone plateaus, gravel plains, dry valleys and salt flats. Around 25% of the desert is sand dunes, some of which reach over 500 ft (152 m) in height.
There are also several mountain ranges within the Sahara and many are volcanic. The highest peak found in these mountains is Emi Koussi, a shield volcano that rises to 11,204 ft (3,415 m). It is a part of the Tibesti Range in northern Chad. The lowest point in the Sahara Desert is in Egypt’s Qattera Depression at -436 ft (-133 m) below sea level.
Most of the water found in the Sahara today is in the form of seasonal or intermittent streams. The only permanent river in the desert is the Nile River that flows from Central Africa to the Mediterranean Sea. Other water in the Sahara is found in underground aquifers and in areas where this water reaches the surface, there are oases and sometimes small towns or settlements like the Bahariya Oasis in Egypt and Ghardaïa in Algeria.
Since the amount of water and topography varies based on location, the Sahara Desert is divided into different geographic zones. The center of the desert is considered hyper-arid and has little to no vegetation, while the northern and southern portions have sparse grasslands, desert shrub and sometimes trees in areas with more moisture.