10 Interesting Facts About The Danube River

The Danube River is one of the most important rivers in the world running across ten European nations. With a length of 2,850 km, it is the second longest river in Europe; and with an annual discharge of 7,130 cu m/s, it is also the second largest river in Europe. The word Danube comes from the Proto-Indo-European root dānu, which means “fluid or, a drop”. The Danube played a key role in one of the greatest ancient civilizations, the Danube Valley Civilization, which flourished for around two millennia.

Today, the Danube is a vital factor in the economy of the European nations it passes through supporting them through transportation; generation of hydroelectricity; industrial and residential water supplies; and irrigation. The Danube, like many rivers over the world, faces numerous challenges including rising pollution which has led to several species in the river being close to extinction. Know more about the history, geography, significance and pollution of the Danube River through these 10 interesting facts.


The name of River Danube comes from the Proto-Indo-European root dānu. The meaning of the word in Rigvedic Sanskrit is a “fluid or, a drop”. In Avestan, the language of Zoroastrian scripture, dānu was a generic word for “river”. The Danube was known to the ancient Greeks as Istros, which stands for “strong and swift”. In Latin, the language of ancient Rome, the river was known as Danubius, or Danuvius. It was in fact worshiped and personified as the Roman river god Danuvius.

Danube Panorama
Panorama of the Danube in Vienna

The modern languages spoken in the Danube basin include German, Hungarian, Romanian, Bulgarian, Portuguese, French, Greek, Italian and Spanish. Today, the River Danube has different names in different languages of the region. Like in German it is called Donau; in Slovak, it is called Dunaj; in Hungarian, Duna; and in Romanian, the lingua franca of Romania and Moldova, it is called Dunărea.


The River Danube is 2,850 km (1,770 mi) long making it the longest river in the European Union and the second longest river in Europe after the Volga. Moreover, it is the 26th longest river in the world. In terms of discharge, the Danube is the 40th largest river in the world with an average annual discharge of around 7,130 m3/s (251,793.574 cu ft./s). This again, is the second most for a European river after the Volga making Danube the second largest river in Europe.

Danube Map
Course of the Danube, marked in red

Danube originates near the town of Donaueschingen, at the confluence of the rivers Brigach and Breg, in the Black Forest of Germany. Thereafter, it flows in the southeastern direction and passes through 10 European nations, namely Germany, Austria, Slovakia, Hungary, Croatia, Serbia, Bulgaria, Romania, Moldova and Ukraine. Finally, it merges into the Black Sea near the border of Romania and Ukraine. The Danube thus flows through 10 countries, which is the most for any river in the world after the Nile, which flows through 11 nations.


The Danube River Basin is usually divided into three sections: upper, middle and lower basins. The Upper Basin extends from the source of the Danube in Germany to Bratislava in Slovakia. The Upper Danube has a rapid current of between 8 and 9 km/hour. The most important tributary in this section is the Morava River, which enters the Danube from the north. The Middle Basin is the largest of the three regions, extending from Bratislava to the dams of the Iron Gate Gorge on the border between Serbia and Romania.

Danube tributaries map
Map of most important tributaries of the Danube

The Middle Danube is more a flatbed river with its speed being around half of Upper Danube. In this section, its most important tributary from the left is the Tisza, which is also the longest tributary of the Danube with a length of 966 km. Its most important right bank tributary in this section is the Sava, which brings the largest discharge of water to the Danube. The lowlands, plateaus and mountains of Romania and Bulgaria form the Lower Basin of the River Danube. The last two large tributaries of the Danube are the Siret and Prut rivers, both of which are left-bank tributaries. The Danube finally divides into three main branches near Tulcea in Romania to form the vast Danube Delta.


The Danube Delta is the second largest river delta in Europe after the Volga Delta. It is also acclaimed as the best preserved on the continent with the greater part of it lying in Romania and a small part in Ukraine. Its approximate surface area is 4,152 sq. km (1,603 sq. mi) of which 3,446 sq. km (1,331 sq. mi) are in Romania and the remaining 706 sq. km (272 sq. mi) in Ukraine.

Danube Delta Satellite Image
Satellite image of Danube Delta

The Danube Delta is a low alluvial plain, mostly covered by wetlands and it consists of an intricate pattern of marshes, channels, streamlets and lakes. Its wetlands support vast flocks of migratory and resident birds of over 300 species, including the endangered pygmy cormorant. On the other hand, the lakes and marshes support 45 freshwater fish species. In 1991, the Romanian part of the Danube Delta became a UNESCO World Heritage Site. Approximately 2,733 sq. km of the delta are strictly protected areas.


The Danube River Basin is the second largest river basin in Europe after the Volga River Basin. It has a total area of 801,463 sq. km (309,447 sq. mi). Moreover, it is the most international basin in the world as it is shared by as many as 19 nations. Apart from the above mentioned countries through which the river flows, its basin also extends into nine more countries, namely Bosnia and Herzegovina, Czech Republic, Slovenia, Montenegro, Switzerland, Italy, Poland, North Macedonia and Albania.

Danube River Basin Map
Map of the Danube River Basin

The Danube river basin stretches from the southwestern part of the Black Forest in Germany to the borders of Romania and Ukraine in the south-east. The fertile terrain of the Danube basin supported some of the earliest Danubian Neolithic human cultures. Today it is home to 83 million people with a wide range of cultures, languages and historical backgrounds.


The Danube Valley Civilization (DVC) existed from around 5,500 BCE to 3,500 BCE and it is one of the oldest known civilizations in Europe. It flourished in the basins of Danube river and was the site of some of the earliest human cultures. The DVC thus predates Ancient Rome and Greece and was the first agrarian society in central and eastern Europe. People living in the Lower Danube Valley and the Balkan foothills were way ahead of their time in art, technology and long-distance trade. Moreover, they farmed and built sizable towns, some with as many as 2,000 dwellings.

The DVC played an important role in the development of copper tools, advanced architecture, a writing system, spinning and weaving. All of these occurred while most of Europe was in the middle of the Stone Age. It is not known why the DVC settlements were abandoned. It is speculated that it might have been due to the land losing its fertility. Danubian sites include those at Bylany in Bohemia and Köln-Lindenthal in Germany.


Danube river is key to the economy of the European nations through which it flows. It provides water resources for transportation; generation of hydroelectricity; industrial and residential water supplies; and irrigation. Industrial use of Danube waters is made at Vienna, Budapest, Belgrade and Ruse; while the main irrigated areas are along the river in Slovakia, Hungary, Serbia and Bulgaria. In addition to this, along its course, the Danube is a source of drinking water for about 20 million people. Danube used to be an important source for fishing activities. However, pollution has diminished its fishes due to which fishing has declined along the river. Still, certain areas on the river have an important fishing industry.

Danube Delta Fisherman
Fisherman in the Danube Delta

Since many fascinating landmarks and natural spots lie along the Danube, leisure and travel cruises on the river are also of great significance. During the peak season, the region along the Danube attracts international clientele leading to the usage of more than 70 cruise liners on the river. All this makes Danube important to the tourism industry.


The upper course of Danube river has been tapped for hydro-power plants mainly due to the natural gradient of the river. The two largest hydro-power dams along the Danube are located at the 117 km long Djerdap Gorge. They are named Iron Gate I and Iron Gate II. The Iron Gate I Hydroelectric Power Station is the largest dam on the Danube and one of the largest hydro-power plants in Europe. The construction of this mega project was jointly undertaken by the Romanian and the Yugoslavian governments. The project started in 1964 and when it was completed in 1972, it was the 10th largest hydroelectric power station in the world.

Iron Gate I
Iron Gate I Hydroelectric Power Station

Today, the Romanian side of Iron Gate I produces approximately 5.24 terawatt hours (Twh) annually while the Serbian side produces 5.65 Twh. The Iron Gate II Hydroelectric Power Station, a joint venture of Romania and Serbia, started its operation in 1984. At the time, it generated a total of 432 MW, divided equally between the two countries. Today it has a total power generation capacity of 591 MW. Both sides of the power station produce around 1.3 TWh annually. Apart from providing hydroelectricity, these dams also make one of the most difficult stretches of Danube navigable.


The habitat created by the Danube and its tributaries is home to numerous species of flora and fauna. These include 2,000 vascular plants and more than 5000 animal species. Of these approximately 5000 animal species, a total of 473 vertebrates (74 fish, 9 amphibians, 12 reptiles and 325 birds) have been reported. Among birds, 60% of the world population of pygmy cormorant and 90% of red-breasted goose can be found here.

Danube Salmon
Danube Salmon or Huchen

The fish species in the Danube include pike, zander, huchen, Wels catfish, burbot and tench. The huchen, one of the largest species of salmon, is endemic to the Danube basin. Eventually, It has been introduced to other major river basins in other parts of the world by humans. Moreover, Danube is home to a large diversity of carp and sturgeon; salmon and trout. Unfortunately, many of these fish species, including sturgeons and the Danube Salmon are close to extinction due to the pollution of the river and other human activities like extensive damming and illegal fishing.


In 2019, a team of researchers led by the University of York studied the antibiotic pollution of rivers and waterways across the world. The study was done to highlight the role played by waterways in strengthening antibiotic resistance of environmental bacteria, which poses a significant threat to public health. According to this study, the Danube is the most polluted river with antibiotics in Europe. Moreover, due to heavy pollution by industries, many species in the river basin are threatened including the sturgeon, a 200 million-year-old fish that produces valuable black caviar.

The Danube is also seeing a rise in plastic waste, pesticide run off and pharmaceutical waste, all contributing to further polluting the river. When European nations realized the gravity of the issue in the 1998, the International Commission for the Protection of the Danube River (ICPDR) was established which consisted of 14 member states. The commission’s goal is to promote and coordinate sustainable and equitable water management, including conservation, improvement and rational use of waters in the whole Danube river basin.

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