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 kilometers² (77,220 miles²), 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.
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.