While water levels of the Caspian Sea have historically fluctuated, the area has seen increasing water volume in the past two decades. The largest inland mass of water (with no outlet) is greatly influenced by the Volga River, which provides more than 80% of the lake.s volume. The Caspian, identified as either an inland sea or the largest lake in the world, is fed by over 120 rivers, but the Volga is the dominant source. Upstream precipitation in the greater Volga Basin contributes to the water levels of the Caspian. In the past decades heavy rains have greatly enlarged the flow into the Sea. The northern portion is characterized by relatively fresh water; because of evaporation, the southern portion has increased salinity.
These Landsat images show a small portion of the Caspian Sea shoreline, in 1985 and again in 2011. Coastal settlements have been flooded, displacing inhabitants and closing industrial facilities. The level of groundwater also is rising, which leads to swamping and salinity of lowland territories. Tyuleniy Island (the prominent island) has visibly lost land mass, and the rising water contributes to the decline of the habitat of the island and the marshes around it that support fowl and other animals.
Landsat imagery are being used by regional and international organizations to monitor changes in the shorelines as they determine the best method to reclaim and preserve biological diversity, and restore environmental and economic balance.