Rivers are described as the arteries of the planet, flowing with water, sediment, and nutrients, upon which people depend for food, water, transportation and many economic aspects of their daily lives.
What are the longest rivers in the world, the shortest and the most flowing with water, and what are their economic importance and the risks they threaten?
What are the most important rivers in the Arab world?
Here are 9 facts you should know about the world's rivers.
The Nile is at the forefront of the world's rivers in terms of length, with a length of 7,088 km (Shutterstock)
Where do rivers originate and where do they drain?
Most rivers originate in lakes, springs, wetlands, and glaciers, and then flow into the seas and oceans, where they empty their waters and the sediments they carry.
However, a few inland rivers have an inland estuary.
The Jordan River, which drains into the Dead Sea, and the Jayhon and Sehun rivers in Uzbekistan, which drain into Lake Khwarazm, are examples of these inland rivers.
How many rivers are there in the world?
There are about 165 major rivers in the world, they are long and wide through which large amounts of water flow every day, and they have tributaries that provide fresh water to billions of people.
Scientists counted the existence of 76 rivers in the world with a length of more than 1,600 km.
The number of permanently flowing rivers on the globe is estimated in the thousands, but it is still not known precisely.
A graph of the ranking of the 10 longest rivers in the world (Al Jazeera)
What is the longest river in the world?
Several operations have been carried out to measure the longest of them, including the measurements made by Chinese researchers in 2009 of the 10 longest rivers in the world and their results were published in the International Journal of Digital Earth.
According to these measurements, the Nile is at the forefront of the world's rivers in terms of length, with a length of 7,088 km, followed by the Amazon River, with a distance of 6,575 km between source and estuary, and then the Yangtze River in China 6,236 km.
The Mississippi River in the United States ranks fourth, with a length of 6,084 km, ahead of the Yenisei River in Siberia, 5,816 km, and the Yellow River in China, 5,778 km.
While the second largest river in Africa, the Congo River, comes in ninth place, with a length of 5,118 km.
It is worth noting that the difference in determining the sources of these rivers leads to a discrepancy in the measurement of their length.
For example, the results of some measurements show that the length of the Nile River is 6,883 km, and others state that it does not exceed 6,650 km if we consider that it originates from Lake Victoria and not from Rwanda and Burundi, as the aforementioned study confirms.
The Amazon is undisputedly the most flowing river in the world (NASA)
What is the shortest river in the world?
According to the World Atlas website, the Tamborasi River in southeastern Indonesia is the shortest river in the world with a length of not more than 20 meters, and a width of 15 meters.
This river is fed by many streams that pass through the mountainous province of Sulawesi.
It is followed by the Kovasselva River, which flows into the Norwegian Sea, and the Reprua River in Georgia with a length of 27 meters, which flows into the Black Sea at a flow rate of 2000 liters per second.
What is the most flowing rivers in the world?
The Amazon is undisputedly the most flowing river in the world, emptying into the Atlantic Ocean about 209,000 cubic meters of water every second.
The Congo River ranks second with an downstream flow rate of about 41 thousand cubic meters per second, followed by the Ganges in Asia with about 38 thousand cubic meters per second.
For comparison, the water flow rate in the Nile seems relatively weak compared to these rivers, as it does not exceed 2,800 cubic meters per second on average.
The Tigris River is the third longest river in the Arab world with a length of 1900 km (Flickr)
What are the most important rivers in the Arab world?
In addition to the Nile, there are several important rivers in the Arab world that provide large amounts of fresh water and contribute significantly to the economic cycle of the region.
Including the Euphrates River, whose length, according to the "World Atlas" website, is about 2,800 km, and is the second longest river in the Arab world.
The river originates from the Armenian Highlands in southeastern Turkey, descends to the Syrian plateau and then flows through the western and central parts of Iraq, before it merges with the Tigris River to form the Shatt al-Arab in the southeastern part of Iraq, and then flows into the Persian Gulf.
The Tigris River is the third longest river in the Arab world, with a length of 1,900 km. It originates from Lake Hazar in the Taurus Mountains in eastern Turkey and then flows southeast through Syria and Iraq towards the Shatt al-Arab.
In the Maghreb, the Draa River in Morocco is the longest river in the region, with a length of about 1,100 km.
It originates in the High Atlas Mountains in Morocco in a southeast direction, where it meets the Dades Valley and the Emni River, and cuts through the Sahara before emptying into the Atlantic Ocean.
The Chlef River, with a length of 725 km, is the longest in Algeria. It originates in the Saharan Atlas Mountains and flows into the Mediterranean.
There are also other rivers in the Arab world of less length, but of economic and agricultural importance, such as the Mejdra River in Tunisia, which is about 460 km long, and the Jordan River is 360 km long.
About 25% of the world's food comes from farmland irrigated by river water (Bixino)
The role of rivers in providing food
According to a report by the World Wildlife Fund, about 25% of the world's food comes from agricultural land irrigated by river water, which also provides 40% of global fish consumption.
Large waterways feed the delta regions with sediments, enabling them to produce 4% of the world's food.
Its flood areas cover at least 10 million hectares, mainly in Asia and Africa, which is equivalent to the area of agricultural land in Italy and enables the production of nearly 1% of the world's food.
Rivers and climate change
An analysis by a team of researchers showed the annual flow between 1948 and 2004 of the 200 largest rivers in the world, an increasing number of those experiencing a decline in the amount of water discharged into the seas.
The analysis revealed that the largest decreases were recorded in the Middle East and North Africa, in the western United States and in South Asia, which means that water stress in those regions will increase in the future with the increase in demand for water.
Another study showed that climate change will have a profound impact on global river discharges in the future.
And the decline in the average discharge over the next 100 years compared to the present time will be similar to what happened during the last 9,000 years.
This is especially true of tropical rivers and some temperate rivers of continental Europe and Asia.
Dams greatly reduce the various benefits that rivers provide to nature (Shutterstock)
Dangers for rivers
According to a study published in the scientific journal Nature in 2019, only a third (37%) of the 246 longest rivers in the world are still free-flowing due to the construction of more than 60,000 dams around the world.
Dams and reservoirs significantly reduce the various benefits that rivers provide to nature around the world.
A report by the World Wildlife Fund issued in 2018 on the status of more than 16 thousand living creatures showed that the types of freshwater creatures - especially those that live in rivers - witnessed a clear decline for all vertebrates over the past half century, declining on average by 83% since 1970.