Click here to load reader

Danube Delta-Popa Elena Alexandra

  • View
    64

  • Download
    3

Embed Size (px)

Text of Danube Delta-Popa Elena Alexandra

Danube Delta

Danube Delta Student:Popa Elena-Alexandra Group : 8219 The Danube Delta is the secondlargest river delta in Europe,afterVolga Delta and is the best preserved on the continent.

Geography and geology

The modern Danube Delta began to form after 4000 BCE in a bay of theBlack Ses, 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 withsediments, the delta advanced outside this barrier-blocked estuary after 3500 BCE, building several successive lobes: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).

Distributaries of the Danube

TheDanubebranches into three maindistributariesinto thedelta,Chilia,Sulina, andSfntul Gheorghe(Saint George). The last two branches form theTulceachannel, which continues as a single body for several kilometers after the separation from the Chilia. At the mouths of each channelgradual formation of new landtakes place, as the delta continues to expand.

Danube ArmLength (km)Flow (m/s)(19211990)Chilia1203800Sulina641250Sfntul Gheorghe(Saint George)701500Climate

The climate of the Danube Delta is continental with strong influences from the vicinity of theBlack Seaand its prevalent amphibian environment. It is the driest and sunniest region of Romania. The mean annual temperature is 11C (-1C in January and 22C in July), with mean precipitation between 400mm/year and 300mm/year, decreasing from west to east. The evaporation is around 1000mm/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.Ecosystems of marshy and flooding areas

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)

History

In 1991, the Romanian part of the Danube Delta became part of theUNESCOlist ofWorld Heritage Sites. Around 2,733km of the delta are strictly protected areas.In 1998, under UNESCOProgramme on Man and the Biosphere, the 6264.03km of Danube Delta were established asBiosphere Reserveshared 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.

Recorded history first noted the Delta underDaciancontrol 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 theOttoman Empire. In 1812, following theRusso-Turkish Warthe borders of Ottoman andRussian Empireswere set by Kilia and Old Stambul Channels of Danube, and in 1829 by St George Channel. TheTreaty of Parisof 1856, which ended theCrimean War, assigned the Danube Delta to theOttoman Empireandestablished an international commission which made a series of works to help navigation. In 1878, following the defeat of Ottoman Empireby Russia and Romania, the border between those two was set by the Kilia and Old Stambul Channels.

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 Ttaru), 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, orpisciculture arrangements. As a result of these changes, as well as the increasing pollution andeutrophicationof the Danube waters, and decades of exploitation and poor regulations of fishing, the fish population has been visibly reduced.

Environment and issues

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 64km, and its flow more than doubled, thus making it suitable for large-vessel navigation. Correcting the six largemeanderson its course thereby reduced the length of the Sfntu Gheorghe from 108km 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.Bibiography http://en.wikipedia.org/wiki/Danube_Deltahttps://www.google.ro/#q=delta+dunarii+imaginihttp://www.ddbra.ro/http://www.deltadunarii.ro/istoric.html

Search related