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Posts tagged Bird’s Foot Delta

Deltas and Wetlands of the Caspian Sea – June 10th, 2009

43.0N 49.9E

June 10th, 2009 Category: Image of the day, Lakes, Rivers

Caspian Sea - June 3rd, 2009

Caspian Sea - June 3rd, 2009

Volga River Delta

Volga River Delta

Ural River Delta

Ural River Delta

Various types of wetland and delta areas can be found on the shores of the Caspian Sea. The northern section of this immense lake is encompassed by the Caspian Depression, a low-lying flatland region.

The depression, which covers approximately 200,000 kilometersĀ² (77,220 milesĀ²), lies at the southern end of the Ryn Desert, and is in both Kazakhstan and Russia.

The Volga River and the Ural River, which forms part of the traditional boundary between Europe and Asia, flow into the Caspian Sea through this region. The deltas of the Ural and Volga Rivers are extensive wetlands.

Both deltas can be observed in detail in their respective close-ups. The fan-shaped Volga River Delta has, unfortunately, experienced significant wetland loss due to industrial and agricultural modification to the delta plain. Much of the water in and around the delta appears bright green due to algal blooms, intensified by fertilizers carried in by the river.

Tengiz Field

Tengiz Field

Kura River and wetlands

Kura River and wetlands

In fact, studies have shown that water pollution, mostly coming from the Volga River, poses a serious threat to the biodiversity of the Caspian Depression. Water pollution is contributed mainly by industrial, agricultural, and household discharges.

The Ural River Delta in Kazakhstan has a different shape from that of the Volga: rather than a wide triangular or fan-shape, it is longer and thinner. This is called a “bird’s foot” or “digitate” delta. Such deltas are often seen on sediment-rich rivers flowing into lakes.

Much of the Caspian Depression is below the level of the sea; its lowest point is 28m (92 ft) below sea level. Its eastern region comprises large areas of marshlands. One such marshy area in western Kazakhstan is the location of the Tengiz Field (see close-up), a huge source of oil.

The final close-up focuses on the western shore of the Caspian Sea, in Azerbaijan. Here, the Kura River enters the sea, discharging sediments. Onland, the dark green area in the center near the coast is swampy Gyzylaghadj State Reserve. Also called the Gizil-Agach State Reserve, it is a Ramsar Wetland that is an important wintering and nesting area for migrant, swamp and wild birds.

Sediments in the Mississippi River Delta – February 11th, 2009

February 11th, 2009 Category: Image of the day, Lakes, Rivers

Louisiana, USA - February 7th, 2009

New Orleans, Louisiana, USA - February 7th, 2009

The city of New Orleans is located in the Mississippi River Delta in southeastern Louisiana, USA. It was built on the shores of Lake Pontchartrain and the Mississippi River, which runs through the city. A bridge, the Lake Pontchartrain causeway, is visible across the center of the lake.

Lake Pontchartrain is flanked by Lake Maurepas (left) and Lake Borgne (right). Lake Maurepas appears dark brown due to sediments, which are particularly visible towards its southern shore. The other two lakes are more green in color, due to algae growth.

The thick tan-colored bands reaching to the East from the left side of the image are agricultural areas and canals built along the banks of the Mississippi River (above) and along various bayous.

The Mississippi River continues east, through New Orleans, then bends south, and finally southeast. The area where the river meets the Gulf of Mexico is called the Bird’s Foot Delta, the newest section of the evolving Mississippi River Delta.

Here, the main branch of the Mississippi River splits into three different directions at its mouth: Southwest Pass (west), Pass A Loutre (east) and South Pass (centre). The location of this split is known as the Head of Passes.

The waters of the Mississippi River are golden brown from sediments, which are carried eastward and flow into the Bird’s Foot Delta and the Gulf of Mexico. This entire area appears light brown and green, as a mix of sediments and algae is present.

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