The Nile
The Nile is the country's main source of water, stretching 1,280 km. In the south, Lake Nasser retains its waters, then flows to the Delta, where it divides into two branches that empty into the Mediterranean Sea. Agriculture develops along the Nile, in the Delta and, on a smaller scale, in the oases of the Libyan desert. The Nile's famous flood cycle was interrupted by the construction of two successive dams at the first cataract, in Aswan. The small dam built in 1902 had already altered the river's cycle, but it was the impoundment of the Aswan High Dam in the late 1960s that gave man total control over the river and its hazards. Since floods no longer deposited the silt that nourished arable land, agriculture was rationalized with increased mechanization and the use of pesticides and fertilizers.
Under the influence of Gamal Abdel Nasser, a project to reclaim land from the desert was launched, with the aim of enlarging arable land and feeding a growing population. All along the Nile, but especially on the margins of the Delta, "new lands" were created using irrigation methods and desert soil enrichment. Major projects were also launched in the 1990s, with less success. The huge "New Valley" project was intended to create a fertile valley west of the Nile, by building a canal to bring water from Lake Nasser from the Toshka pumping station northwards to the Oasis region to the east. The project seems to have been reduced to the conquest of land near the canal and pumping station.
These land conquest projects are also linked to the demographic challenge facing the country. Successive governments over the past two decades have embarked on the construction of numerous urban developments in the desert lands surrounding pre-existing urban centers. This phenomenon has increased sharply in recent years as a solution to strong demographic pressure on resources and services. The official aim of building a new administrative capital in the desert east of Cairo is to relieve congestion in the Egyptian capital, which is often paralyzed by traffic jams and marked by uncontrolled urban growth. The new city is expected to accommodate over 7 million inhabitants, as well as the seat of power, ministries and embassies. However, these gigantic projects are beset by financing problems and the scarcity of available natural resources, especially water. This is where part of the country's future is currently at stake.
The sources of the Nile. Strictly speaking, the Nile, 6,500 km long, rises from two lakes: Lake Victoria, which gives rise to the White Nile, and Lake Tana, which gives rise to the Blue Nile. At 68,100 km2, Lake Victoria is the largest of Africa's great lakes. It is fed by rainfall in April and September, as well as by various rivers.
Lake Tana, in Ethiopia, is contained in a depression formed by lava flow during the Tertiary Era. It is smaller than Lake Victoria, at 3,600 km2, and is also shallow, not exceeding 14 m in depth. It is fed by rainfall, which increases from June to September. While rainfall is the most important source, several smaller rivers also feed the river.
The White Nile, 3,700 km long, is an effluent of Lake Victoria, which it leaves in the north to flow through Uganda under the name of the Victoria Nile. It flows into Lake Kioga, on the border between Uganda and Kenya, then follows its course with the impressive Murchison Falls.
500 km after leavinǵ Lake Victoria, it then flows into Lake Albert. It then joins South Sudan, where it forms an immense wetland that has long been the Nile's exploration limit. These swamps cover almost 60,000 km2, the equivalent of Lake Victoria. Since the early 20th century, the Jongleï canal project has been under discussion, with the aim of channelling the river's waters to reduce the marsh's high evaporation rate for irrigation purposes. The Nile is then joined by the Sudanese river Sobat which, through the white sediments it carries, has giveń its name to the White Nile. It continues its course into Sudan, where it joins the Blue Nile at Khartoum.
The Blue Nile, 1,450 km long, rises in Lake Tana in Ethiopia. It flows southwards, then continues its course through 400 km of sometimes very deep gorges, in stark contrast to the exuberant greenery of the landscapes it traverses. The famous Nile floods were mainly due to the rainy season, which caused the Blue Nile and its tributaries to swell. The Ethiopian highlands were also the source of fertile silt, the cornerstone of agriculture in ancient Egypt until the 1960s. Today, these sediments are held back by Ethiopian dams and the Aswan High Dam. Since Ethiopia built the Renaissance Dam, the question of sharing the Nile's waters has been a source of great diplomatic tension between the countries bordering the Nile. This issue highlights the redefinition of the balance of power in the region in the post-Arab Spring period.
The Egyptian Nile, or Great Nile, is 3,000 km long. It is the confluence of the Blue and White Niles, which meet at Khartoum in Sudan. On average, 59% of its water comes from the Blue Nile, but this figure can rise to 80% during the rainy season.
The Atbara is the most important tributary of the Egyptian Nile, providing 25% of the river's water in August, at the height of the rainy season. There are six rapids along the Nile, known as cataracts. They are all located between Khartoum and Aswan. They are often formed by granite boulders that create eddies and hinder navigation. The Meroe Dam partially submerged the fourth cataract, and the second is now submerged by the waters of Lake Nasser. Lake Nasser stretches some 480 km from the Sudanese border to Aswan, where the first cataract is located. This immense lake, also known as the Nubian Sea, represents a freshwater reserve of over 162 billionm3 for Egypt! While it is necessary for irrigation and flood control, it also retains the fertile silt from the river, which agglomerates at the bottom of the lake.
This gives the town of Aswan its grandiose landscapes, where the Nile now flows quietly between huge blocks of pink granite. The Nile then continues its course to Cairo and the entrance to the Delta. It is on these shores that we find the most beautiful monuments of Egyptian civilization: Elephantine, Edfu, Luxor, Karnak, Memphis.
Its banks are the charm of Upper Egypt or the Saïd, as the Egyptians call it. The river flows through lush fields of palm, banana and sugar cane, overlooked by the yellow mountains that frame the valley.
The Nile Delta. Shaped like a lotus, the delta covers an area of 24,000 km2, with the northern part bordering the Mediterranean and reaching a width of 250 km. In ancient times, the Nile, whose course is unique to Upper Egypt, divided into seven branches north of Memphis, in its delta. Today, only two branches remain: the Bolbitine branch, which flows east to Rachid (Rosetta), and the Phatnitic branch, which flows west to Damietta. The others have disappeared as man has intervened and the riverbed has changed in this marshy area. This is a particularly fertile region, thanks to the accumulation of silt. The delta is now subject to increased erosion due to the reduction in silt since the construction of the Aswan dam. This phenomenon is accompanied by a worrying increase in salinization of the land closest to the coast. This fertility makes it the country's most important agricultural region and a particularly densely populated area.
The Libyan desert and the oases
Between the west bank of the Nile and the Libyan border lies the Libyan desert. This extension of the Sahara covers two thirds of the country. It is formed of low-lying plateaus and is covered with sand dunes sometimes 300 to 400 m high. Depressions dig it in places. The largest of these is that of Qattara, 134 m below sea level and covers 18,000 km2. The springs that emerge at the bottom of these depressions, and which are fed by a water table, have led to the emergence of oases: from north to south, the oases of Siwa, Wadi Natroun, Bahareyya, Farafra, Dakhla and Kharga follow one another. The Fayoum, also located in a depression, cannot be considered a real oasis since the water present does not come from the water table but from the Nile, which overflows there at each annual flood. It is in the Libyan desert that the black and white deserts are found, prized by visitors for its impressive geological formations and sublime landscapes.
The Arabian desert
On the eastern bank of the Nile, the Arabian Desert rests on a fragment of the African continental plate, raised on the edge of the Red Sea and the Gulf of Suez by plate tectonics. It rises from the Nile valley to an altitude of 610 m in the east and along the Red Sea coast it rises to steep and jagged peaks culminating at an altitude of 2,135 m. The Arabian Desert is the largest desert in Africa. Until recently a sparsely inhabited region, it is now the subject of intense development of tourist towns on the Red Sea coast.
The desert of Nubia
In the far south, along the border with Sudan, the Nubian Desert is a vast area of dunes and sand plains. Its gold deposits have been exploited for a long time and were used to supply the treasure of the pharaohs. The Bedjas nomads live there with their herds. The region of the Hala'ib triangle is the site of a geopolitical dispute between Sudan and Egypt. Sudan claims it, but since 2000, the territory has been under Egyptian administration.
Sinai
Sinai is a peninsula located geographically on the Asian continent. Framed by the Suez and Aqaba tectonic troughs, the peninsula is connected to the Arabian desert by the isthmus of Suez. In its northern part, Sinai is a sandy expanse that extends into a central plateau. The southern part of the peninsula is dominated by rocky mountains, culminating at 2,642 m with Mount Sainte-Catherine. The south of Sinai offers varied and magnificent landscapes, once again accessible without security constraints.
