Danube Delta

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UNESCO World Heritage Site
Danube Delta
( Delta Dunării )
Name as inscribed on the World Heritage List
Image from the Danube Delta
Type Natural
Criteria vii, x
Reference 588
UNESCO region List of World Heritage Sites in Europe
Inscription history
Inscription 1991 (15th Session)
Where the Danube Meets the Black Sea (NASA Goddard image).

The Danube Delta (Romanian: Delta Dunării pronounced [ˈdelta ˈdunərij] ( ); Ukrainian: Дельта Дунаю, Del'ta Dunaju) is the second largest river delta in Europe, after Volga Delta, and is the best preserved on the continent.[1] The greater part of the Danube Delta lies in Romania (Tulcea county), while its northern part, on the left bank of the Chilia arm, is situated in Ukraine (Odessa Oblast). The approximate surface area is 4,152 km², and of that, 3,446 km² are in Romania. With the lagoons of Razim-Sinoe (1,015 km² with 865 km² water surface), located south of the main delta, the total area of the Danube Delta reaches 5,165 km². The Razelm - Sinoe lagoon complex is geologically and ecologically related to the delta proper and their combined territory is part of the World Heritage Sites.

Danube Delta near Tulcea (2010)

Geography and geology[edit]

The modern Danube Delta began to form after 4000 BCE in a bay of the Black Sea, when the sea rose to its present level. A sandy barrier blocked the Danube bay where the river initially built its delta. Upon filling the bay with sediments, the delta advanced outside this barrier-blocked estuary after 3500 BCE, building several successive lobes:[2] the St. George I (3500-1600 BCE), the Sulina (1600-0 BCE), the St. George II (0 BC-Present) and the Chilia or Kilia (1600 CE to present). Several other internal lobes were constructed in the lakes or lagoons bordering the Danube delta to the North (Chilia I and II) and toward the South (Dunavatz).[3] Much of the alluvium in the delta and a major expansion of its surface area in the form of lobes resulted from soil erosion associated with clearing of forests in the Danube basin during the 1st and 2nd millennium.[4][5] Geologist Liviu Giosan told The New York Times that:

Probably 40 percent of the Delta was built in the last 1000 years. Finding that was like a eureka moment.”[4]

At present the delta suffers from a large sediment deficit after the construction dams on Danube and its tributaries in the later half of the 20th Century. However, construction of a dense network of shallow channels in the delta over the same period attenuated the deficit on the delta plain but increased erosion at the coast [6][7] The Danube Delta is a low alluvial plain, mostly covered by wetlands and water. It consists of an intricate pattern of marshes, channels, streamlets and lakes. The average altitude is 0.52 m, with 20% of the territory below sea level, and more than half not exceeding one meter in altitude. Dunes on the most extensive strandplains of the delta (Letea and Caraorman strandplains) stand higher (12.4 m and 7 m respectively). The largest lakes are Dranov (21.7 km²), Roșu (14.5 km²), Gorgova (13.8 km²).

Danube Delta - Dalmatian Pelican and Great Cormorant


Distributaries of the Danube[edit]

The Danube branches into three main distributaries into the delta, Chilia, Sulina, and Sfântul Gheorghe (Saint George). The last two branches form the Tulcea channel, which continues as a single body for several kilometers after the separation from the Chilia. At the mouths of each channel gradual formation of new land takes place, as the delta continues to expand.

Main Distributaries of the Danube

Danube Arm Length (km) Flow (m³/s)

(1921–1990)

Chilia 120 3800
Sulina 64 1250
Sfântul Gheorghe

(Saint George)

70 1500

Chilia, in the north, the longest, youngest, and most vigorous, with two secondary internal deltas and one microdelta in full process of formation at its mouth (to Ukraine).

Sulina, the central and thus the shortest arm, which consequently led to its extensive use for traffic and severe transformation. At its mouth is located the main port and the single settlement with urban characteristics of the Romanian part of the delta. Because of the alluvium deposited at its mouth, a channel gradually advancing into the sea (presently it has 10 km), was built in order to protect the navigation.

Sfântul Gheorghe (Saint George in English), in the south, is the oldest and more sparsely populated. Its alluvium has led to the creation, beginning with 1897, of the Sacalin islands, which today measure 19 km in length.

Map created in 2010

Interactive webmap of the Danube Delta

Climate[edit]

The climate of the Danube Delta is continental with strong influences from the vicinity of the Black Sea and its prevalent amphibian environment. It is the driest and sunniest region of Romania. The mean annual temperature is 11 °C (-1 °C in January and 22 °C in July), with mean precipitation between 400 mm/year and 300 mm/year, decreasing from west to east. The evaporation is around 1000 mm/year, amplified by the strong and frequent winds, resulting in long periods of drought in the summer. The northwest winds cause frequent storms in spring and autumn. In the interior of the delta the continental character of the climate is very pronounced.

Main ecosystems[edit]

Danube Delta in Romania
Danube Delta: old mill in Letea

The Danube Delta falls within Pannonian steppe ecosystem of eastern Europe, with Mediterranean influences. As a young region in full process of consolidation, the Danube Delta represents a very favourable place for the development of highly diverse flora and fauna, unique in Europe, with numerous rare species. It hosts 23 natural ecosystems, but due to the extent of wetlands the aquatic environment is prevalent; the terrestrial environment is also present on the higher grounds of the continental levees, where xerophile ecosystems have developed. Between the aquatic and terrestrial environments, is interposed a swampy, easily flooded strip of original flora and fauna, with means of adaptation for water or land, depending on the season or the hydrological regime. At the contact between freshwater and sea water, some special physical, chemical and biological processes take place, which have led biologists to consider this area as a very different ecosystem called beforedelta. Musura Gulf, north of Sulina, and Saint George Gulf are considered the most representative for this type of ecosystem.

Situated on major migratory routes, and providing adequate conditions for nesting and hatching, the Danube Delta is a magnet for birds from six major eco-regions of the world, including the Mongolian, Arctic and Siberian. There are over 320 species of birds found in the delta during summer,[8] of which 166 are hatching species and 159 are migratory. Over one million individuals (swans, wild ducks, bald coots, etc.) winter here.

Ecosystems of running water[edit]

It comprises the Danube arms, as well as a series of more important streamlets and channels. It is an environment rich in plankton, worms, mollusca, ephemerides, grubs, spongiae, with numerous species of fish, such as the carp, pike perch, sheat fish, and freshwater sturgeons (sterlet, Vyza and Danube mackerel).

Ecosystem of stagnant water[edit]

Includes the lakes, to which various ponds, streamlets and channels are added. They are characterized by a rich floating and submerse flora (Myriophyllum, Ceratophyllum, Vallisneria etc. under the water; Nymphaea alba, Nuphar lutea, Trapa natans, Alisma plantago etc., floating plants with roots near the lakes borders; Salvinia natans, Stratiotes aloides, Spirogyra etc., floating plants without roots, having negative effects for the aquatic bioproductivity). Of the fish, the most important are Tinca tinca, Abramis brama, Scardinius erytrophalmus, Carassius auratus gibelio, Silurus glanis, Perca fluviatilis, Esox lucius etc.

Ecosystems of marshy and flooding areas[edit]

Pelicans in Danube Delta
The Danube Delta birds: Grey Heron (Ardea cinerea), Mallard or Wild Duck (Anas platyrhynchos), Great White Pelican (Ardea cinerea), Great Crested Grebe (Podiceps cristatus). Stamp of Romania, 2004.

The reed plats and floating reed islands (called plaur in Romania) are the most common and well known components of the Danube Delta. Vegetation of this ecosystem consists of common reed (Phragmites communis), and near river banks mace reed (Typha latifolia, Typha angustifolia), sedge (Carex dioica, Carex stricta), Dutch rush (Scirpus radicans, Scirpus lacustris), brook mint (Mentha aquatica) etc. They constitute ideal spawning and nestling grounds. The plaur is a mixture of reed roots, grass and soil, usually floating or anchored on the bottom. As a rule, the reed surrounds the lakes and ponds, slowly invading the water surface.

This type of ecosystem is noted for the variety and large populations of birds, some of them very rare. The most important are the tufted duck (Aythya fuligula, red crested pochard (Netta rufina), mallard (Anas platyrhynchos), Greylag goose (Anser anser), Pygmy cormorant (Phalacrocorax pygmaeus), purple heron (Ardea purpurea), Great white egret (Egretta alba), little egret (Egretta garzetta), Spoon bill (Platalea leucorodia), White pelican (Pelecanus onocrotalus), Dalmatian pelican (Pelecanus crispus), Mute swan (Cygnus olor), Glossy ibis (Plegadis falcinellus). A recent and welcomed spreading has the pheasant (Phasianus colchicus).

Among the mammals, there is the otter (Lutra lutra), mink (Mustela lutreola), little ermine (Mustela erminea aestiva), wild boar (Sus scrofa), wild cat (Felis silvestris), and in the winter, the hare (Lepus europaeus), and on the brink of disappearing from the delta, the wolf and the fox. The raccoon dog (Nyctereutes procyonoides), bizam (Onda zibethica), and to some extent nutria (Myocastor coypus) are recent species successfully adapted.


River banks and levees ecosystems[edit]

Nycticorax nycticorax' AM1 slepowron.jpg
Paleogeography of Danube Delta, since Petre Gâstescu é Romulus Stiuca

The firm land of the delta used to be covered with large groves of willow trees, cut almost entirely and replaced with Canadian poplars. On the riverbanks kept in natural state, small groves of willow trees (Salix alba, Salix fragilis, Salix purpurea, Salix petandra, Salix triandra etc.) can still be found, mixed with white poplar (Populus alba). Occasionally, the willow trees form corridors along the Danubes arms and bigger channels. On the levees of Letea and Caraorman, mixed forests of oaks (Quercus robur, Quercus pedunculiflora) with various trees (Fraxinus pallisae, Ulmus foliacea, Populus tremula), shrubs (Prunus spinosa, Crataegus monogyna, Rosa canina, Berberis vulgaris etc.), and vines (Vitis sylvestris, Hedera helix, Humulus lupulus, Periploca graeca, which reaches up to 25m) grow on sand dunes. On the Letea levee, these exotic looking forests grow especially in the depressions between the sand dunes, in small groves called hasmace. Fauna of this region includes Meadow Viper (Vipera ursinii), Osprey (Pandion haliaetus), Eagle Owl (Bubo bubo), etc.


Inhabitants[edit]

Lipovan fisherman of Chilia Veche
Vylkove (Ukraine), 1962
The "M&B" natural reservations of the Danube delta (red: in Ukraine; yellow: in Romania)

The Danube Delta is perhaps the least inhabited region of temperate Europe. In the Romanian side live about 20,000 people, of which 4,600 in the port of Sulina, which gives an average density of approx. 2 inhabitants per km². The rest is scattered in 27 villages, of which only three, all situated marginally, have more than 500 people (2002). The city of Tulcea, at the western edge of the delta, has a population of 92,000 (2002). It represents the node of the region and the gate to the delta.

Sulina City - 1870 Lighthouse

The acute isolation and the harsh conditions of living, based mainly on subsistence, made the Danube Delta a place of emigration, or at least of transit. Very few of the people born here stay through adulthood; at the same time, the origins of the inhabitants fall within a wide range, as people from the most various places of Romania can be found in the delta. The total population has somewhat remained constant throughout the 20th century; there were 12,000 inhabitants in the 1890s, and 14,000 before the Second World War. Romanians count for approximately 80%, and Ukrainians for 10%. Other people living in the delta include ethnic miorities like Greeks, Turks and Bulgarians (1992). Distinctive for the region, but very rare as an ethnic entity are the Lipovans, descendants of the Orthodox Old Rite followers who fled Russia in the 18th century from religious persecution. About a third of the employed population is engaged in fishing and pisciculture, while another third is engaged in farming (1996). However, the quasi-totality practice fishing, more or less legally, as a means of subsistence or extra money.

In the Ukrainian side, located at the northern edge of the delta, the town of Izmail has a population of 85,000, Kiliya, 21,800 and Vilkovo, the main center of Lipovan community, 9,300.


History[edit]

The Danube Delta in 1867, as a part of the Ottoman Empire

Recorded history first noted the Delta under Dacian control before being conquered by the Romans. After invasion by the Goths the region changed hands many times. During the 15th century, the Danube Delta became part of the Ottoman Empire. In 1812, following the Russo-Turkish War the borders of Ottoman and Russian Empires were set by Kilia and Old Stambul Channels of Danube, and in 1829 by St George Channel. The Treaty of Paris of 1856, which ended the Crimean War, assigned the Danube Delta to the Ottoman Empire and established an international commission which made a series of works to help navigation. In 1878, following the defeat of Ottoman Empire by Russia and Romania, the border between those two was set by the Kilia and Old Stambul Channels.

Territorial losses of Romania in the Danube delta since 1948

In 1991, the Romanian part of the Danube Delta became part of the UNESCO list of World Heritage Sites. Around 2,733 km² of the delta are strictly protected areas.

In 1998, under UNESCO Programme on Man and the Biosphere, the 6264.03 km² of Danube Delta were established as Biosphere Reserve shared by Romania and Ukraine.

Historically, in Romania, part of Danube Delta was marked as a reserve back in 1938.

In Ukraine, the Danube branch of Black Sea State Reserve was established in 1973. In 1981 it was reorganized into Natural Reserve "Danube Fluxes", and in 1998 it was extended into Danube Biosphere Reserve.


Environment and issues[edit]

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Reeds growing in the Danube Delta

Large-scale works began in the Danube Delta as early as the second half of the 19th century. First corrections of the Sulina arm began in 1862, and they continued throughout the 20th century. As a result, the length of the Sulina arm was reduced from 92 to 64 km, and its flow more than doubled, thus making it suitable for large-vessel navigation. Correcting the six large meanders on its course thereby reduced the length of the Sfântu Gheorghe from 108 km to 108, and its flow also increased somewhat. Both these increases were made to the detriment of the Chilia arm, which at present remains the most unspoiled arm of the main three. These corrections, as well as the digging of various secondary channels throughout the body of the delta, have had a serious impact on the ecosystem. Natural environments have been altered, the breeding pattern of fish has been disrupted, and the flows in the main arms have increased, with serious consequences regarding the discharge of the alluvia and the erosion of the banks.

Danube Delta, fisherman.jpg

Reed was intensively harvested during the Communist era. The regime had plans of transforming the delta into a large agro-industrial zone. Although the first modern agricultural exploitation dates from 1939 (Ostrovul Tãtaru), only after 1960 were large areas drained and converted, to the detriment of wetlands. In 1991 agricultural land in the delta surpassed 100,000 hectares, and more than a third of its surface has been affected by crop cultivation, forest plantation, or pisciculture arrangements. As a result of these changes, as well as the increasing pollution and eutrophication of the Danube waters, and decades of exploitation and poor regulations of fishing, the fish population has been visibly reduced.

In 2004, Ukraine inaugurated work on the Bistroe Channel that would provide an additional navigable link from the Black Sea to the populous Ukrainian section of the Danube Delta. However, because of the negative impact which this new channel may have upon the fragile ecosystem of the Delta, the European Union advised Ukraine to shut down the works. Romanian officials threatened to sue Ukraine at the International Court of Justice. Under the presidency of Kuchma Ukraine had responded that Romania is just afraid of the competition that the new channel will bring, and continued working on the channel. Under the presidency of Yuschenko, who visited Romania in 2005, both sides agree that professionals should decide the fate of the channel. In the long-run, Ukraine plans to build a navigation channel, if not through Bistroe Channel then through another channel.

See also[edit]

Geography of Romania
Topography

Carpathians (peaks)
Plains & Delta
Islands

Hydrography

Rivers (Danube)
Lakes
Black Sea

Climate

A series of articles on control of the Danube, in chronological order

References[edit]

  1. ^ Danube Delta - UNESCO World Heritage Centre
  2. ^ Giosan et al., 2006, Young Danube delta documents stable Black Sea level since the middle Holocene: Morphodynamic, paleogeographic, and archaeological implications, Geology, 34, 757–760 (2006). [1][2]
  3. ^ Giosan et al., 2009, Early Anthropogenic Transformation of the Danube-Black Sea System, Scientific Reports, 2, 582, [3][4]
  4. ^ a b Rachel Newer (September 14, 2012). "Comments From Ancient Deforestation, a Delta Is Born". The New York Times. Retrieved September 17, 2012. 
  5. ^ Liviu Giosan, Marco J. L. Coolen, Jed O. Kaplan, Stefan Constantinescu, Florin Filip, Mariana Filipova-Marinova, Albert J. Kettner, & Nick Thom (August 30, 2012). "Early Anthropogenic Transformation of the Danube-Black Sea System". Scientific Reports 2 (article number 582). doi:10.1038/srep00582. Retrieved September 17, 2012. Sediment loads delivered by Danube River, the main tributary of the Black Sea, significantly increased as land use intensified in the last two millennia, which led to a rapid expansion of its delta. 
  6. ^ Giosan et al., 2009, Maintenance of large deltas through channelization: Nature vs. humans in the Danube delta. Anthropocene.
  7. ^ http://www.whoi.edu/news-release/maintaining_deltas
  8. ^ Danube Delta - UNESCO World Heritage Centre

External links[edit]

Coordinates: 45°05′00″N 29°30′00″E / 45.0833°N 29.5°E / 45.0833; 29.5