The Three Zones of the Volga Delta, Russia – May 20th, 200946.7N 47.8E
The Volga Delta is located in Russia’s Astrakhan Oblast. It is the largest inland river delta in Europe, and occurs where Europe’s largest river system, the Volga River, drains into the Caspian Sea in the Caspian Depression. The far eastern part of the delta extends into Kazakhstan.
The delta lies in the arid climate zone, characterized by very little rainfall. The region receives less than one inch of rainfall in January and in July in normal years.
Strong winds often sweep across the delta and form linear dunes. Along the front of the delta, one will find muddy sand shoals, mudflats, and coquina banks. Green algae, nourished by fertilizers, is present in the waters around the delta.
The Volga Delta has grown significantly in the past century because of changes in the level of the Caspian Sea. In 1880, the delta had an area of 3,222 km². Today the Volga Delta covers an area of 27,224 km² and is approximately 160 km across.
The changing level of the Caspian Sea has resulted in three distinct zones in the delta. The higher areas of the first zone are known as “Behr’s mounds,” which are linear ridges of clayey sands ranging from 400 m to 10 km in length, and averaging about eight meters in height. Between the Behr’s mounds are depressions that fill with water and become either fresh or saline bays.
The second zone, in the delta proper, generally has very little relief (usually less than one meter), and is the site of active and abandoned water channels, small dunes and algal flats.
The third zone is composed of a broad platform extending up to 60 km offshore, and is the submarine part of the delta.