Danube

Etymology

Danube is an Old European river name derived from the Celtic 'danu' or 'don'^[16] (both Celtic gods), which itself derived from the Proto-Indo-European *deh₂nu. Other European river names from the same root include the Dunaj, Dzvina/Daugava, Don, Donets, Dnieper, Dniestr, Dysna and Tana/Deatnu. In Rigvedic Sanskrit, danu (दनु) means "fluid, dewdrop" and danuja (दनु-ज) means "born from danu" or "born from dew-drops". In Avestan, the same word means "river". The Finnish word for Danube is Tonava, which is most likely derived from the name of the river in German, Donau. Its Sámi name Deatnu means "Great River". It is possible that dānu in Scythian as in Avestan was a generic word for "river": Dnieper and Dniestr, from Danapris and Danastius, are presumed to continue Scythian *dānu apara "far river" and *dānu nazdya- "near river", respectively.^[17]

In Latin, the Danube was variously known as Danubius, Danuvius, Ister^[18] or Hister. The Latin name is masculine, as are all its Slavic names, except Slovene (the name of the Rhine is also masculine in Latin, most of the Slavic languages, as well as in German). The German Donau (Early Modern German Donaw, Tonaw,^[19] Middle High German Tuonowe)^[20] is feminine, as it has been re-interpreted as containing the suffix -ouwe "wetland".

Romanian differs from other surrounding languages in designating the river with a feminine term, Dunărea (IPA: [ˈdunəre̯a]).^[10] This form was not inherited from Latin, although Romanian is a Romance language.^[14] To explain the loss of the Latin name, scholars who suppose that Romanian developed near the large river propose^[14] that the Romanian name descends from a hypothetical Thracian *Donaris. The Proto-Indo-European root of this presumed name is related to the Iranic word "don-"/"dan-", while the supposed suffix -aris is encountered in the ancient name of the Ialomița River, Naparis, and in the unidentified Miliare river mentioned by Jordanes in his Getica.^[10] Gábor Vékony says that this hypothesis is not plausible, because the Greeks borrowed the Istros form from the native Thracians.^[14] He proposes that the Romanian name is a loanword from a Turkic language (Cuman or Pecheneg).^[14]

International status

Once a long-standing frontier of the Roman Empire, the river passes through or touches the borders of 10 countries. Its drainage basin extends into nine more (ten if Kosovo is included).^[21]

Drainage basin

In addition to the bordering countries (see above), the drainage basin includes parts of nine more countries: Bosnia and Herzegovina (4.6% of the basin area), the Czech Republic (2.9%), Slovenia (2.0%), Montenegro (0.9%), Switzerland (0.2%), Italy (<0.15%), Poland (<0.1%), North Macedonia (<0.1%) and Albania (<0.1%).^[21] The total drainage basin is 801,463 km² (309,447 sq mi) in area,^[22][23] and is home to 83 million people.^[24] The highest point of the drainage basin is the summit of Piz Bernina at the Italy–Switzerland border, at 4,049 m (13,284 ft).^[25] The Danube River Basin is divided into three main parts, separated by "gates" where the river is forced to cut through mountainous sections:^[24]

• Upper Basin, from the headwaters to the Devín Gate.
• Middle Basin, usually called the Pannonian basin or Carpathian Basin, between the Devín Gate and the Iron Gates. It includes the Hungarian plains Kisalföld and Alföld.
• Lower Basin, from the Iron Gates to the river mouth, including the Danube Delta.

Discharge

Mean annual discharge on the hydrological stations (period from 2000 to 2023); 1 - Reni, Isaccea; 2 - Silistra; 3 - Pristol; 4 - Batina, Bezdan; 5 - Nagymaros, Szob; 6 - Bratislava, Wolfsthal; 7 - Untergriesbach^[2][26][27]

Multiannual average, minimum and maximum discharge (water period from 1876 to 2010)^[28][29]

Simulated water and suspended sediment results from climate-driven decadal study (with STD through specific decade):^[30]

P – Simulated average precipitation in the Danube basin; T – Simulated average temperature in the Danube basin; Q – Simulated average discharge in the Danube River at delta; S – Simulated sediment load in the Danube River at delta;

Tributaries

The land drained by the Danube extends into many other countries. Many Danubian tributaries are important rivers in their own right, navigable by barges and other shallow-draught boats. From its source to its outlet into the Black Sea, its main tributaries are (as they enter):

• 
  The Danube's source confluence in Donaueschingen: the Donauzusammenfluss, the confluence of Breg and Brigach.
• 
  0 km, Danube Delta, Ukraine
• 
  Where the Danube meets the Black Sea (European Space Agency Sentinel-2 image)
• 
  The Danube discharges into the Black Sea (the upper body of water in the image).

Cities and towns

The Danube flows through many cities, including four national capitals (shown below in bold), more than any other river in the world. Ordered from the source to the mouth they are:

• Germany
  • Donaueschingen in the State of Baden-Württemberg – rivers Brigach and Breg join to form the Danube
  • Möhringen an der Donau in Baden-Württemberg
  • Tuttlingen in Baden-Württemberg
  • Sigmaringen in Baden-Württemberg
  • Riedlingen in Baden-Württemberg
  • Munderkingen in Baden-Württemberg
  • Ehingen in Baden-Württemberg
  • Ulm in Baden-Württemberg
  • Neu-Ulm in Bavaria
  • Günzburg in Bavaria
  • Dillingen an der Donau in Bavaria
  • Donauwörth in Bavaria
  • Neuburg an der Donau in Bavaria
  • Ingolstadt in Bavaria
  • Kelheim in Bavaria
  • Regensburg in Bavaria
  • Straubing in Bavaria
  • Deggendorf in Bavaria
  • Passau in Bavaria

• Austria
  • Linz, capital of Upper Austria
  • Krems in Lower Austria
  • Tulln in Lower Austria
  • Vienna – capital of Austria and the most populous city on the Danube, where the Danube floodplain is called the Lobau, though the Innere Stadt is situated away from the main flow of the Danube (it is bounded by the Donaukanal – 'Danube canal').

• Slovakia
  • Bratislava – capital of Slovakia
  • Komárno
  • Štúrovo

• Hungary
  • Mosonmagyaróvár
  • Győr
  • Komárom
  • Esztergom
  • Visegrád – This section of the river is also called Danube Bend.
  • Vác
  • Szentendre
  • Göd
  • Dunakeszi
  • Budapest – capital of Hungary, the largest city and the largest agglomeration on Danube (about 3,300,000 people).
  • Szigetszentmiklós
  • Százhalombatta
  • Ráckeve
  • Adony
  • Dunaújváros
  • Dunaföldvár
  • Paks
  • Kalocsa
  • Baja
  • Mohács
• Croatia
  • Vukovar
  • Ilok

• Serbia
  • Apatin
  • Bačka Palanka
  • Čerević
  • Futog
  • Veternik
  • Novi Sad – regional capital of Vojvodina
  • Sremski Karlovci
  • Zemun
  • Belgrade – capital of Serbia
  • Pančevo
  • Smederevo
  • Kovin
  • Veliko Gradište
  • Golubac
  • Donji Milanovac
  • Kladovo

• Bulgaria
  • Vidin
  • Lom
  • Kozloduy
  • Oryahovo
  • Nikopol
  • Belene
  • Svishtov
  • Ruse
  • Tutrakan
  • Silistra

• Romania
  • Moldova Nouă
  • Orșova
  • Drobeta-Turnu Severin
  • Calafat
  • Bechet
  • Dăbuleni
  • Corabia
  • Turnu Măgurele
  • Zimnicea
  • Giurgiu
  • Oltenița
  • Călărași
  • Fetești
  • Cernavodă
  • Hârșova
  • Brăila – limit of the maritime sector of the Danube
  • Galați – largest port on the Danube
  • Isaccea
  • Tulcea
  • Sulina
• Moldova
  • Giurgiulești
• Ukraine
  • Reni
  • Izmail
  • Kiliia
  • Vylkove

Panorama of the Danube in Vienna

The Danube Bend is a curve of the Danube in Hungary, near the city of Visegrád. The Transdanubian Mountains lie on the right bank (left side of the picture), while the North Hungarian Mountains on the left bank (right side of the picture).

Panorama of the Danube in Budapest with the Hungarian Parliament (left)

Budapest at night

Panorama of the Danube in Novi Sad from Petrovaradin Fortress, Serbia

The confluence of the Sava into the Danube at Belgrade. Pictured from Belgrade Fortress, Serbia

Panoramic image of the Danube and Sava river from Kalemegdan, Belgrade Serbia

The Danube entering the Iron Gate at the South-Western end of the Carpathian Mountains. Romania on the left side, Golubac Fortress and Serbia on the right side.

Islands

• Ada Kaleh Island
• Ostrovul Mare, Gogoșu
• Balta Ialomiței
• Belene Island
• Csepel Island
• Čakljanac Island
• Donauinsel
• Forkontumac Island
• Great Brăila Island
• Great War Island
• Island of Mohács
• Koh Chang Island, Sremski Karlovci
• Kozloduy Island
• Margaret Island
• Ostrovo (Kostolac)
• Ostrovul Ciocănești
• Ostrovul Mare, Islaz
• Paradajz Island
• Ribarsko Оstrvo [sr], Novi Sad
• Island of Šarengrad
• Szigetköz
• Island of Szentendre
• Vardim Island
• Island of Vukovar
• Žitný ostrov

Sectioning

• Upper Section: From spring to Devín Gate, at the border of Austria and Slovakia. Danube remains a characteristic mountain river until Passau, with average bottom gradient 0.0012% (12 ppm), from Passau to Devín Gate the gradient lessens to 0.0006% (6 ppm).
• Middle Section: From Devín Gate to Iron Gate, at the border of Serbia and Romania. The riverbed widens and the average bottom gradient becomes only 0.00006% (0.6 ppm).
• Lower Section: From Iron Gate to Sulina, with average gradient as little as 0.00003% (0.3 ppm).

Ecology and environment

The International Commission for the Protection of the Danube River (ICPDR) is an organization that consists of 14 member states (Germany, Austria, the Czech Republic, Slovakia, Slovenia, Hungary, Croatia, Bosnia and Herzegovina, Serbia, Bulgaria, Romania, Moldova, Montenegro, and Ukraine) and the European Union. The commission, established in 1998, deals with the whole Danube river basin, which includes tributaries and groundwater resources. Its goal is to implement the Danube River Protection Convention by promoting and coordinating sustainable and equitable water management, including conservation, improvement, and rational use of waters and the implementation of the EU Water Framework Directive and the Danube Strategy.

Navigation

The Danube Commission is concerned with the maintenance and improvement of the river's navigation conditions. It was established in 1948 by seven countries bordering the river. Members include representatives from Austria, Bulgaria, Croatia, Germany, Hungary, Moldova, Slovakia, Romania, Russia, Ukraine, and Serbia; it meets regularly twice a year. It also convenes groups of experts to consider items provided for in the commission's working plans.

The commission dates to the Paris Conferences of 1856 and 1921, which established for the first time an international regime to safeguard free navigation on the Danube. Today the Commission include riparian and non-riparian states.

Ancient cultural perspectives of the lower Danube

Part of the rivers Danubius or Istros was also known as (together with the Black Sea) the Okeanos in ancient times, being called the Okeanos Potamos (Okeanos River). The lower Danube was also called the Keras Okeanoio (Gulf or Horn of Okeanos) in the Argonautica by Apollonius Rhodos (Argon. IV. 282).

At the end of the Okeanos Potamos, is the holy island of Alba (Leuke, Pytho Nisi, Isle of Snakes), sacred to the Pelasgian (and later, Greek) Apollo, greeting the sun rising in the east. Hecateus Abderitas refers to Apollo's island from the region of the Hyperboreans, in the Okeanos. It was on Leuke, in one version of his legend, that the hero Achilles was buried (to this day, one of the mouths of the Danube is called Chilia). Old Romanian folk songs recount a white monastery on a white island with nine priests.^[49]

Rivalry along the Danube

This section does not cite any sources. (February 2013)

Between the late 14th and late 19th centuries, the Ottoman Empire competed first with the Kingdom of Serbia, Second Bulgarian Empire, Kingdom of Hungary, Principality of Wallachia, Principality of Moldavia and later with the Habsburg monarchy, Polish–Lithuanian Commonwealth, and Russian Empire for controlling the Danube (Tuna in Turkish), which became the northern border of the Ottoman Empire for centuries. Many of the Ottoman–Hungarian Wars (1366–1526) and Ottoman–Habsburg wars (1526–1791) were fought along the river.

The most important wars of the Ottoman Empire along the Danube include the Battle of Nicopolis (1396), the Siege of Belgrade (1456), the Battle of Mohács (1526), the first Turkish Siege of Vienna (1529), the Siege of Esztergom (1543), the Long War (1591–1606), the Battle of Vienna (1683), the Great Turkish War (1683–1699), the Crimean War (1853–1856) and the Russo-Turkish War (1877–1878).

Second World War

During the 2011 renovation of the Margaret Bridge, Budapest, human remains were discovered. The mostly Jewish remains were victims of the far-right Arrow Cross Party, who briefly governed Hungary from 1944.^[50]

Drinking water

Along its course, the Danube is a source of drinking water for about 20 million people.^[51][52] In Baden-Württemberg, Germany, almost 30 percent (as of 2004) of the water for the area between Stuttgart, Bad Mergentheim, Aalen and Alb-Donau (district) comes from purified water of the Danube. Other cities such as Ulm and Passau also use some water from the Danube.

In Austria and Hungary, most water is drawn from ground and spring sources, and only in rare cases is water from the Danube used. Most states also find it too difficult to clean the water because of extensive pollution; only parts of Romania where the water is cleaner still obtain drinking water from the Danube on a regular basis.^[53]

Navigation and transport

In the 19th century, the Danube was an important waterway but was, as The Times of London put it, "annually swept by ice that will lift a large ship out of the water or cut her in two as if she were a carrot."^[54]

Today, as "Corridor VII" of the European Union, the Danube is an important transport route. Since the opening of the Rhine–Main–Danube Canal, the river connects the Port of Rotterdam and the industrial centers of Western Europe with the Black Sea and, also, through the Danube – Black Sea Canal, with the Port of Constanța.

The waterway is designed for large-scale inland vessels (110 × 11.45 m) but it can carry much larger vessels on most of its course. The Danube has been partly canalized in Germany (5 locks) and Austria (10 locks). Proposals to build a number of new locks to improve navigation have not progressed, due in part to environmental concerns.

Downstream from the Freudenau locks in Vienna, canalization of the Danube was limited to the Gabčíkovo dam and locks near Bratislava and the two double Iron Gate locks in the border stretch of the Danube between Serbia and Romania. These locks have larger dimensions. Downstream of the Iron Gate, the river is free flowing all the way to the Black Sea, a distance of more than 860 kilometres (530 mi).

The Danube connects with the Rhine–Main–Danube Canal at Kelheim, with the Donaukanal in Vienna, and with the Danube–Black Sea Canal at Cernavodă.

Apart from a couple of secondary navigable branches, the only major navigable rivers linked to the Danube are the Drava, Sava and Tisa. In Serbia, a canal network also connects to the river; the network, known as the Danube–Tisa–Danube Canals, links sections downstream.

In the Austrian and German sections of the Danube, a type of flat-bottomed boat called a Zille was developed for use along the river. Zillen are still used today for fishing, ferrying, and other transport of goods and people in this area.

Fishing

The importance of fishing on the Danube, which was critical in the Middle Ages, has declined dramatically. Some fishermen are still active at certain points on the river, and the Danube Delta still has an important industry. However, some of the river's resources have been managed in an environmentally unsustainable manner in the past, leading to damage by pollution, alterations to the channel, and major infrastructure development, including large hydropower dams.^[55]

The sturgeon stocks associated with the Danube River basin have, over the centuries, formed the basis of a large and significant commercial fishery, renowned throughout the world. The construction of the dams, besides overfishing and river pollution, has a significant role in sturgeon population decline because it creates a barrier for fish migratory species that usually spawn in the upper parts of the river.^[56] The spawning areas of migratory fishes species has been dramatically reduced by the construction of hydropower and navigation systems at Iron Gates I (1974) and Iron Gates II (1984).^[57] The initial design of these dams has not included any fish passage facility.^[58] The possibility of building a human-made fish pass enabling migration for fish species including the sturgeon, is currently under review by projects such as We Pass.^[59]

The Upper Danube ecoregion alone has about 60 fish species and the Lower Danube–Dniester ecoregion has about twice as many.^[60] Among these are an exceptionally high diversity of sturgeon, a total of six species (beluga, Russian sturgeon, bastard sturgeon, sterlet, starry sturgeon and European sea sturgeon), but these are all threatened and have largely–or entirely in the case of the European sea sturgeon–disappeared from the river.^[60] The huchen, one of the largest species of salmon, is endemic to the Danube basin, but has been introduced elsewhere by humans.^[61]

Tourism

Important tourist and natural spots along the Danube include the Wachau Valley, the Nationalpark Donau-Auen in Austria, Gemenc in Hungary, the Naturpark Obere Donau in Germany, Kopački rit in Croatia, Iron Gate in Serbia and Romania, the Danube Delta in Romania, and the Srebarna Nature Reserve in Bulgaria.

Also, leisure and travel cruises on the river are of significance. Besides the often frequented route between Vienna and Budapest, some ships even go from Passau in Germany to the Danube Delta and back. During the peak season, more than 70 cruise liners are in use on the river, while the traffic-free upper parts can only be discovered with canoes or boats.

The Danube region is not only culturally and historically of importance, but also important for the regional tourism industry due to its fascinating landmarks and sights. With its well established infrastructure regarding cycling, hiking, and travel possibilities, the region along the Danube attracts every year an international clientele. In Austria alone, there are more than 14 million overnight stays and about 6.5 million arrivals per year.^[62]

The Danube Banks in Budapest are a part of Unesco World Heritage sites, they can be viewed from a number of sightseeing cruises offered in the city.

The Danube Bend is also a popular tourist destination.

Danube Bike Trail

The Danube Bike Trail (also called Danube Cycle Path or the Donauradweg) is a bicycle trail along the river. Especially the parts through Germany and Austria are very popular, which makes it one of the 10 most popular bike trails in Germany.^[63]

The Danube Bike Trail starts at the origin of the Danube and ends where the river flows into the Black Sea. It is divided into four sections:

1. Donaueschingen–Passau (559 km or 347 mi)
2. Passau–Vienna (340 km or 210 mi)
3. Vienna–Budapest (306 km or 190 mi)
4. Budapest–Black Sea (1,670 km or 1,040 mi)

Donausteig

In 2010, the Donausteig, a hiking trail from Passau to Grein, was opened. It is 450 km (280 mi) long and it is divided into 23 stages. The route passes through five Bavarian and 40 Austrian communities. A landscape and viewpoints, which are along the river, are the highlights of the Donausteig.^[64]