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THE MARSH ARABS - HISTORY

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Author Topic: THE MARSH ARABS - HISTORY  (Read 3651 times)
Bianca
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« Reply #15 on: August 14, 2007, 09:28:55 pm »

                                 
Space view of the Mesopotamian Marshlands taken by the earth observation satellite Landsat in 1973-76. Dense marsh vegetation (mainly Phragmites) appears as dark red patches, while red elongated patches long river banks are date palms.







The Marshlands of Lower Mesopotamia





The extensive but shallow marshlands of the lower Tigris-Euphrates basin represent an outstanding natural landmark of Mesopotamia. They comprise the largest wetland ecosystem in the Middle East and Western Eurasia. A rare aquatic landscape in desert milieu, the marshlands are home to ancient communities rooted in the dawn of human history. They also provide habitat for important populations of wildlife, including endemic and endangered species. The key role played by the marshlands in the inter-continental flyway of migratory birds, and in supporting coastal fisheries endows them with a truly global dimension. For these reasons, the Mesopotamian marshlands (called Al Ahwar in Arabic) have long been recognised to constitute one of the world's most significant wetlands and an exceptional natural heritage of the Earth. Most recently, the World Wide Fund for Nature (WWF) placed the Mesopotamian marshlands in its select list of two hundred exceptional ecoregions in the world for priority conservation (the Global 200).

Situated for the main part in southern Iraq (2955' to 3245' N and 4525' to 4830' E), the wetlands covered in 1970 an estimated area ranging from 15,000 - 20,000 square kilometres. The eastern margins of the marshlands extend over the border into southwestern Iran. In terms of custodianship, they therefore constitute a transboundary ecosystem under shared responsibility. 3.1 Formation of the Marshlands Understanding how the marshlands of lower Mesopotamia were formed historically is crucial to grasping how they have been affected by water management projects. The topography of the lower Tigris-Euphrates



The marshlands support the inter-continental migration of birds. Pelicans congregate in marshland lagoon.
valley is distinguished by an extremely flat alluvial plain. The Euphrates falls only 4 cm/ km over the last 300 km, while the Tigris has a slope of 8 cm/km (Scott, 1995). As a result of the level terrain, both rivers deviate from a straight course, meandering in sinuous loops and eventually divide into distributaries that dissipate into a vast inland delta. This is particularly true of the Euphrates, whose velocity rapidly diminishes as it lacks tributaries along its lengthy course, and begins to develop a braided pattern nearly 520 km upstream of the Gulf. Immediately south of Al Nasiriyah, the Euphrates main channel dissolves into the marshes, only to re-emerge shortly before its confluence with the Tigris at Al Qurnah. The Tigris, which is drained along its eastern flank by several tributaries from the mountains and hills of the Zagros chain, has a relatively stronger hydraulic force, enabling it to maintain a more stable course. Nonetheless, in its lower stretches around Al Amarah, the Tigris also rapidly begins to lose its velocity and flares out into multiple distributary channels feeding directly into the marshes. Water extraction by an elaborate irrigation network criss-crossing the alluvial plain between the two rivers significantly reduces water flow, and contributes to the rivers' splitting into a diffuse array of shallow waters in their final stretches.
« Last Edit: August 14, 2007, 09:41:11 pm by Bianca2001 » Report Spam   Logged

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