Carving the Earth for millions of years, rivers or streams in general, constitute vast networks of arteries and veins that irrigate the planet and bring life. But which ones travel the surface of the globe the longest?
Before revealing the classification of these river giants, it should be noted that the last of this classification already runs for more than 5,500 km while the Loire, which is the largest French river, measures only 1,012 km and that the largest course of European water, the Volga, runs for only 3,701 km.
Here are the top 5 longest rivers that flow on the surface of our planet.
© Neil PALMER / CIAT
Accurately determining the length of a watercourse is a complex task as geographers must define both where it begins and where it ends, which is why the Amazon and the Nile have been during centuries at the center of a rivalry for the title of “longest river in the world”. Although in the 20th century, a scientific consensus had given primacy to the African river over its South American rival, the claims of researchers from the Brazilian Institute of Geography and Statistics reshuffled the cards in 2007 by proposing Mount Mismi, snow-capped mountain in southern Peru, as the Amazon’s new source. This proposal extended the length of the Amazon by 284 km, exceeding that of the Nile by 105 km. The Amazon would therefore be 6,800 km long, crossing Peru, Colombia and Brazil before flowing into the Atlantic Ocean.
This South American river artery collects records as that of the most important flow in the world, around 206,000 m3 / s on average and brings nearly 20% of the fresh water to the oceans. This mighty river also has the largest basin in the world, covering an area of approximately 6.9 million km2. In addition, it contains around 13% of biodiversity and is home to nearly 40% of the world’s tropical rainforest. But the Amazon is today threatened by many hydroelectric dam projects under construction or under study, on its rivers and tributaries, which would have devastating consequences on the environment.
© Patrick HERTZOG / AFP
Downgraded to second place in the ranking, the Nile nevertheless remains the longest river on the African continent with 6,695 km. The Nile basin covers more than 3 million km2 or 10% of the surface area of Africa, divided between two large areas: the White Nile from Lake Victoria and the Blue Nile from Lake Tana in Ethiopia. It spans eleven countries: Burundi, Democratic Republic of Congo, Egypt, Ethiopia, Eritrea, Kenya, Uganda, Rwanda, South Sudan, Sudan and Tanzania. With an average flow of around 2,830 m3 / s, it is barely more powerful than the Rhône but remains very modest compared to its African counterparts such as the Congo or Niger rivers. It flows into the Mediterranean Sea through a vast delta.
Celebrated as a deity in the time of the Pharaohs, the Nile is a source of life for some 500 million inhabitants of North-East Africa, whether for drinking water needs or for those related to irrigation. It alone provides 97% of the Egyptians’ water supply. But it must face major challenges such as the pollution of its waters, a galloping demography concentrated on its shores, climate change as well as the sharing of its waters, a source of sharp tensions between riparian countries such as the conflict. which pits Egypt, Sudan and Ethiopia against the subject of the Great Renaissance Dam called GERD, an Ethiopian mega-dam built on the Blue Nile.
the yangzi jiang or yang-tse-kiang
© Dong ZHANG / UNSPLASH
A long-time source of inspiration for artists, the Yangzi Jiang is the third longest river in the world. Also called in Chinese “Chang Jiang” which means “Long River”, it has long been known in France under the name of the blue river or Yang-Tsé-Kiang, an old transcription closer to its pronunciation in Chinese for French speakers. The longest river in China and the Asian continent, it originates in the high Tibetan mountains and winds for 6,357 km through Chinese territory to empty into the East China Sea, near Shanghai. The waters of the river and its tributaries form a hydrographic basin of 1.8 million km2 which accommodates nearly a third of the Chinese population, or 400 million inhabitants. With an average flow rate of 22,000 m3 / s, it drains the water from 3,600 tributaries on its way. It is the refuge of a unique biodiversity in the world with its many and varied natural ecosystems and contributes nearly 40% of China’s freshwater resources. In addition, it plays a central role in the Chinese agricultural economy especially rice farming and fish farming. On its 2,800 km of waterways dotted with river ports, there has always been a very active traffic in the transport of goods, raw materials or energy.
However, just like the other river giants, the Yangzi Jiang is confronted with problems linked to climate change, to the construction of gigantic infrastructures that block its waters, such as the Three Gorges dam, which was put into service in 2003 and which represents the largest hydraulic works in the world, but also to demographic pressure and increased economic development on its shores, sources of numerous pollution. Faced with the urgency of the situation, the Beijing government adopted a law in December 2020 to protect it. This legislative text to protect a waterway in the country, a first for China, entered into force in March 2021 and should help ease the pressure exerted on the Yangzi Jiang.
© DSEARLS / CC BY 2.0
Fourth in the ranking of the longest rivers in the world, the Mississippi is the largest waterway in North America with 6,275 km taking into account its tributaries like the Missouri. The origin of its name comes from the word “Misi-Ziibi” of the Native American Ojibwe language which translates as “Great River”. Born from the waters of Lake Itasca in Minnesota, in the north of the United States, it crisscrosses ten American states before flowing into the Gulf of Mexico through a huge delta. The Mississippi is one of the largest river basins in the world, covering 3.3 million km2, or 40% of the territory of the United States, if we exclude Alaska. Mythical and iconic river of North America, described and popularized by the greatest American writers, still occupies a large place in the life but also in the imagination not only of the people of the South but also among the majority of the inhabitants. the United States.
With an average flow at its mouth of 18,000 m3 / s, the Mississippi is an essential artery of the American economy which allows the irrigation of cereal crops, the operation of various industries and power stations. It also ensures the transport of goods and raw materials since 10% of the goods of the United States pass through its river ports. In addition, more than fifty cities and 18 million people depend directly on the Mississippi and its tributaries for their daily water needs.
Still, the authorities responsible for watching over the Mississippi must find solutions to resolve the recurring problem of devastating floods and floods created by the overflows of the river. Pollution and overconsumption of its water are other subjects of major concern even if clear progress in this area has been recorded since 1972, when a law, the Clean Water Act was passed by Congress. But the major challenge facing part of the Mississippi River are the impacts of climate change, which are profoundly modifying its ecosystem and threatening the very existence of its delta as well as the safety of its inhabitants.
the iénisseÏ or enisei
© OLFIIKA / CC BY-SA 2.0
This Russian river which flows in eastern Siberia is the fifth longest river in the world. With a width of between 15 and 20 km, it flows over a length of 5,539 km Born from the confluence of the Great Yenisei and the Little Yenisei, it winds along the border between eastern and western Siberia, before flowing into in the Kara Sea, in the Arctic Ocean. The basin of this Russian river covers more than 2.58 million km2 and represents the largest Arctic watershed. This vast territory is full of mineral resources and raw materials as well as the largest deposits of oil and gas.
It is the most powerful river in Russia because its average flow at the mouth is 19,800 m3 / s, outclassing all other rivers in the country. But this is only an annual average because the Yenisei is frozen for five months of the year, so there is a huge gap between its period of low water and that of high water. The hydroelectric potential of the Yenissei and its main tributaries like the Angara, was exploited from the 1950s and allowed economic and industrial development of the region. For example, the Krasnoyarsk dam on the Yenisei, commissioned between 1967 and 1971, is the second most powerful hydroelectric generator in Russia, the first being that of Saiano-Shushensk which is located upstream on the same river. The Yenisei is also a major axis of communication on which transit raw materials such as wood, coal, copper or nickel, as well as petroleum products and manufactured goods.
But the flip side is that the Yenissei is very ill. Human activity has contributed to the pollution of water from mining and metallurgy and the petroleum industry. In addition, the waters of the Russian river suffer from plutonium contamination following the release of radioactive particles for several decades from a chemical-industrial complex working in the manufacture of the nuclear arsenal of the Soviet army, placed at the heart of a secret city located 60 km downstream from the city of Kranoyarsk. Finally, the regulation of the flow of rivers and the grabbing by the industrial sector of the available water resource favors the depletion of the Siberian river giant.