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Geography
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Introduction
The Arab Republic of Egypt occupies the northeast corner of Africa, lying within the great Sahara Desert. It is bordered on the north by the Mediterranean Sea, on the south by the Republic of Sudan, on the west by Libya, and on the east by Israel, the Gulf of Aqaba, and the Red Sea. This geographical position has made Egypt a hub of world trade since ancient times.
Egypt has a total area of 1 million square kilometers (386,100 square miles) of land—almost twice the size of Spain. Barren deserts occupy more than 90 percent of the country. The Nile separates the dunes of the Western Desert from the mountainous Eastern Desert. These two deserts, the Nile Valley, and the Sinai Peninsula make up Egypt's four geographic areas.
Western (Libyan) Desert
From the Nile's western bluffs, sand- and gravel-strewn plateaus stretch westward, covering more than two-thirds of Egypt's territory. The Western Desert has no external drainage system; runoff from its occasional rainstorms pours into central depressions, forming transitory lakes that, when dry, leave salt deposits. Potable water is limited to artesian wells in a string of oases that occur in depressions across the plateaus.
The Eastern (Arabian) Desert
In the south, the Eastern Desert rises 2,000 meters (6,562 feet) in steep hills and cliffs to the backbone of volcanic, granite, sedimentary, and metamorphic rocks that hugs the Red Sea coast. To the west and north, the mountains give way to plateaus. Both are intersected by ancient drainage beds called wadis, relics from the Pleistocene when heavy rains scoured their slopes. These wadis coalesce into major east-west arteries that served as ancient highways, establishing major trading routes to southwest Asia.
Today, rainwater from occasional storms quickly percolates into the gravel and sand lining these wadis, creating underground reserves that can be tapped by shallow wells. This water also feeds natural springs scattered throughout the range.
Nile Valley
The Nile derives from three tributaries: The White Nile flows from Lake Victoria in Uganda, passing through a series of marshes in Sudan before joining the Blue Nile at Khartoum. The Blue Nile originates in the Ethiopian highlands.
At Khartoum, the Nile plunges into a sandstone and granite canyon, where its waters roil through a series of cataracts. In this section, the Nile is joined by its final major tributary, the Atbara, before it is harnessed by Aswan High Dam.
Flowing steadily north into Upper Egypt, the river passes the pharaonic temples at Luxor (ancient Thebes). Not until the river moves north once more does the valley begin to widen and widespread cultivation begin. The capital of Memphis once stood just south of Cairo. As the delta shifted northward, so did the capital, until it became established at present-day Cairo.
North of Cairo the Nile branches, spreading water and alluvium over the delta, which fans along the Mediterranean coast between Alexandria and Port Said. The delta includes some of Africa's most fertile soils.
Sinai Peninsula
Sinai's 61,000 square kilometers (23,552 square miles) are separated from the rest of Egypt by the Red Sea and the chain of lakes and waterways forming the Suez Canal. This small subcontinent links Africa and Asia. It is a geological extension of the mountainous Eastern Desert, occupying 6 percent of Egypt's total land area.
Climate
With the exception of the strip bordering the Nile and the Mediterranean Sea, Egypt is desert.
Expect dramatic temperature swings in the desert. When the sun rises, sand and rock begin to heat, radiating warmth into the dry air. Daytime temperatures may reach nearly 54° C (130° F), and temperatures as high as 78° C (170° F) have been recorded. When the sun sets, the desert cools as rapidly as it warmed. Temperature changes over 37° C (100° F) have been recorded in a 24-hour period.
Rainstorms in the desert are uncommon and unpredictable—they may be decades apart. When storms do strike, they are often violent and localized. In such torrential downpours, entire mud-brick villages have been washed away.
Egypt's winds, in contrast, are predictable. They sweep across the land from the north, bringing cooling breezes from the Mediterranean. In the desert, the wind can lift sand up to 2 meters (6 feet) from the ground, creating a shifting, billowing layer above the land.
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