Delta of the Mississippi

The delta of the Mississippi form the mouth of the river the Mississippi in the state of Louisiana in the south of the the United States. This delta is formed by the alluvia deposited by the river whereas it is thrown in water of the Gulf of Mexico. It continues to advance towards the south. The delta of the Mississippi constitutes a rich person ecosystem threatened by the human activities. The delta of the Mississippi covers a surface of 75 000 km ² (more than 400 km of 200 depth km width (of is in west) (of north in the south)), on which some 2,2 million inhabitants lives, majority living in the agglomeration of New-Orleans. However, compared with other deltas, the density of the area is relatively low.

Formation of the delta

The mouth of the Mississippi moved several times. In 5 000 years, the river changed nine times of mouths and the current one dates only from the 10th century. When a channel was built at the beginning of the 19th century, the river sought to join the bed and the mouth of the river Atchafalaya, to 95 km of La Nouvelle-Orléans. The Body of the engineers of the American army maintains the dams to preserve the usual course of the river.

The current delta

The grounds of the delta tend to be inserted; in same time, the river and its arms bring alluvia and sediments which accumulate. However these deposits decrease because of the stoppings built on the rivers of the basin of the Mississippi. Human installations (channels, dams, conduits) block the water run-off of the river.

The delta of the Mississippi increases approximately by 100 meters, supplied per annum with the 730 million tons of Alluvions which it deposits at a rate of 60 centimetres per annum on the bottom of its bed, which requires a constant dredging to ensure navigation. These deposits form immense a Alluvial cone which gains easily on water of the Gulf of Mexico because the low depth of water and the low amplitude of the tides. The mud and clays prevent the river from curving.

Natural environments of the delta

The delta of the Mississippi is “the greatest littoral wetland of all United States”. The delta offers various landscapes, energy of the brackish Lagune S, with the Mangrove or the Marais of fresh water. The deltaic plain of the Mississippi includes the coastal marshes of Louisiana and covers 28.568 square kilometers. It is characterized by a complex network of arm and natural liftings which radiate starting from the river downstream from Baton-Rouge.

Flora

The timbering of the delta is dominated by various species of Chêne S and the Cyprès bald person, which is being the emblematic tree of the state of Louisiana. In the aquatic environments develop, in other, the hyacinths of water.

Fauna

The fauna of the delta is varied: among the most known animals, one can quote the American Alligator, several species of tortoise S and of Serpent S. the mammals are also numerous: beaver S, Raccoon, Otter of river, Mink of America, Muskrat, Small polatouche, Opossum of Virginia, Armadillo with nine bands, etc One also finds many species of bat. Many birds nest in the delta of the Mississippi: Héron S, Brush S, Pelican S brown and white, Ibis and Owl X. Other species come to winter in the area: it is about the wild Oie, of the Canard of America, the Canard pintail or the Osprey. The Sea eagle with white head and the Peregrine falcon are threatened species. In water of the marshes or rivers, one finds crayfish S, catfishes, ( Cycleptus elongatus , representatives of the family of the Sciaenidae and Catostomidae. A species of sturgeon ( Scaphirhynchus albus ) is threatened of extinction.

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