Next only perhaps to the mountains, famous rivers in the world are the natural phenomena which contributed the most in the development of human civilizations. Containing mostly fresh water, rivers are the natural waterways flowing from higher altitudes towards the lower altitudes or from mountains to the sea. In many cases, however, the river dries up or is absorbed before reaching another body of water or the sea. The opposite direction of the flow of a river is termed as ‘up river’ and towards the flow is called the ‘down river’ direction. The study of rivers is a regular science now and is known as potamology. ‘River flow’ is defined as the volume of water passing through a predetermined cross section of a river in a unit of time. It is usually measured in cubic meters per second. Not all the rivers are permanent; some are only temporary and flow only during high rainfall. Rivers are classified differently and according to one system devised by William Morris Avis, they are classified according to their age and are known as youthful, mature, or old rivers. The youthful rivers have a high corrosion energy, and they are deeper, while the mature rivers’ flow is slower, and they are comparatively shallow. The old rivers have the least corrosion and flow rate.
1. The Nile River
The Nile River, pyramids, and the ancient Egyptian civilization seem to be an inseparable trio, and none can be perceived fully without taking into consideration the other two. According to the Greek historian Herodotus, ‘Egypt was the gift of the Nile.’ The River Nile is 6,650 km, and it is the longest river in the world. It is the seat of the earliest human civilization. The Nile River flows through many countries including; Egypt, Uganda, Ethiopia, Kenya, Tanzania, Congo, Rawanda, Burundi, South Sudan, and Sudan. The Nile River has two tributaries, the White Nile and the Blue Nile. The former flows through Tanzania, Lake Victoria, Uganda, and southern Sudan, while the Blue Nile, beginning at Lake Tana in Ethiopia, flows into Sudan, and its northern part flows through the desert and Egypt. Almost all the historical sites of the ancient Egyptian civilization are found alongside the river bank. The end of the Nile is a large delta that discharges into the Mediterranean Sea.
2. The Amazon River
The Amazon River flowing through South America is the second-longest river in the world with the fastest flow rate. The Amazon is about 6,400 km long, and its width at an average varies from 1.6 to 10 km, but it expands up to 48 km during rains and it is on account of its vast expanse that it is sometimes called the River Sea. The Amazon is about 25 meters deep at an average, but at places it is 100 meters deep. The drainage area of the Amazon is equal to almost one-fifth of the world’s overall river flow. The Amazon is a favorite of habitat of over 1,500 species of fish.
The Yangtze is the third longest river in the world, and the longest river of Asia. It measures about 6,418 km. Flowing from the Qinghai Plateau of Tibet through the southwest, eastern, and central China, it ultimately empties into the eastern China Sea in Shanghai. It has its bearing upon the Chinese culture. The Yangtze is to China what the Nile is to Egypt. The delta of the Yangtze comprises very fertile land, and the produce of the area has a significant contribution in the Chinese economy. The largest hydroelectric power station in the world, called ‘The Three Gorges Dam’ is built upon this river. The Yangtze provides a sustainable ecosystem for the preservation of its biodiversity, and a few of its sections are the UNESCO World Heritage Sites. Industrial wastes have polluted the river in recent years.
4. Mississippi River
The Mississippi River derives its name from ‘Misi-Zibi’ meaning ‘Great River.’ Rising from Northern Minnesota and flowing through many States of America, it ends at the Mississippi River Delta, flowing ultimately into the Gulf of Mexico. It is about 3,734 meters long with an average discharge of 16,792 cubic meters per second. It is the tenth largest and fourth longest river of the world, flowing through or bordering many States including: Minnesota, Wisconsin, Illinois, Tennessee, Missouri, Iowa, Kentucky, Arkansas, and Louisiana. On account of the silt deposits, the areas alongside the Mississippi River are very fertile.
5. The Seine
The Seine River is 776 km long, rises from the Langres Plateau, and flows right through Paris. It was only too shallow having only eight meters as an average depth. Therefore, to make it navigable, special arrangements were made to raise the water level. The upstream is the transport to town, and the downstream is located in aristocratic Paris. It is listed as a world heritage on account of a number of historic buildings and places like the Eiffel Tower. Paris is the Seine River City and known for having most of the world’s best pieces of artwork. In 2003, after a first-level flood alert, they were removed from Paris proactively as most of them were being stored in basements.
6. The River Indus
The River Indus originates from the Tibetan Plateau and flows through Ladakh, Jammu, Kashmir, Gilgit, and Baltistan. It runs throughout the length of Pakistan ultimately flowing into the Arabian Sea near the seaport, Karachi. It is 3,180 km long. Whereas it is the major river of Pakistan having 93 percent of it, India shares 5 percent and China shares 2 percent of the Indus River. In an Indian sacred book of hymns in Sanskrit, namely Rig-Veda, the Indus River has been mentioned many times. It is one of the oldest rivers of the world associated with the oldest Indus Valley civilization. The Blind Indus Dolphin is a protected species.
7. The Ganges
Rising from the Himalayas in the Indian state of Uttarakhand and flowing through Northern India and Bangladesh, the Ganges empties into the Bay of Bengal. It is one of the top 20 rivers in respect of discharge and is the longest river of India. The Ganges River basin is the most populated basin in the world with an average density of 1,000 inhabitants per square mile. The Ganges is the most sacred river for Hindus and revered as a ‘Ganga’ deity. The water of the Ganges River is a source for washing away sins and spiritual purification. The Ganges is one of the most polluted five rivers of the world. It is a bordering river between India and Bangladesh.
8. The Euphrates
The Euphrates is one of the oldest rivers of the world, and its history is traceable to 3000 BC as referred to in the pictographic script on clay tablets discovered in Southern Iraq. The Euphrates originates from Eastern Turkey and flows through Syria and Iraq while meeting the Tigris in Shat al-Arab and ultimately flowing into the Persian Gulf. It receives water mostly from the melting of snow and rains. The flow rate is at its peak in the rainy months of April and May. Construction of many dams and the increased use of its water for irrigation has reduced its flow rate from 7,510 cubic meters per second before 1990 to only 2,514 cubic meters per second after 1990.
9. The Niagara River
Originating from Lake Erie, the 58 km long Niagara River flows at an average rate of 5,796 cubic meters per second. Flowing through America and Canada, it ultimately falls into Lake Ontario. Its basin area is estimated at 684,000 square kilometers. It is a bordering river between the Ontario province of Canada and the state of New York in America. The river includes the world famous Niagara Falls, which have moved about 11 kilometers upstream during the last 12,000 years, but the corrosion has been reduced after the building of huge plants over it for the generation of electricity.
10. The River Thames
Rising from Thames Head in Gloucestershire, the River Thames flows through London which gives it a special importance. Thames itself gives significance and imparts its name to many other places like Thames Head, Thames Gateway, Thames Valley, Thames Estuary, Henley on Thames, Kingston upon Thames, etc. With a total length of 346 km, the river flows along many cities which include: Oxford, Reading, Henley on Thames, Windsor, Kingston upon Thames, and Richmond. The river has been an important source of food, drink, hydropower and other human activities for more than 1,000 years.
Human populations and cities started developing on the banks of rivers for the obvious reason of the numerous advantages of the rivers. Rivers have long since been valuable resources for water for drinking and irrigation, food in the form of fish, birds, and mammalian milk and meat, hydropower, transportation, gravel and sand as building materials. Whereas the rivers have been very friendly to mankind, at times they have been so unkind and devastating too in the form of floods. Floods bring destruction which are invariably followed by an era of constructive developments and better crop yields due to the after flood deposits of fertile sediments. Rivers have also served as borders between different countries.