Caspian Sea: State of the Environment 2019

1. Introduction The Caspian Sea is a unique natural reservoir, located between Europe and Asia. Covering an area of around 392,600 km 2 , the Caspian Sea is the world’s largest landlocked water body, lying 27 m below sea level (Baltic elevation system). The water area is equal to the area of the Baltic Sea (387,000 km 2 ) and is larger than that of the Adriatic Sea (139,000 km 2 ). Based on the features of its morphological struc- ture and physical and geographical conditions, the Caspian Sea is divided into three distinct regions: the Northern Caspian (25 per cent of the area), the Middle Caspian (36 per cent of the area) and the Southern Caspian (39 per cent of the area). The conditional Northern–Middle Caspian border passes through Chechen Island and Tyub-Karagan, while the Middle–Southern border passes through Chilov Island and Cape Gan-Kuuli The maximum depth of the sea’s

southern basin, known as the Southern Caspian depression or Lankaran depression, is 1,025 m with a mean depth of 208 m. The sea measures 1,030 km in length, from north to south, and 435 km in width, from east to west. The Caspian Sea is bordered by Azerbaijan, Iran, Kazakhstan, the Russian Federation and Turk- menistan, whose estimated coastlines are 955 km, 1,000 km, 2,320 km, 695 km and 1,200 km respectively. The sea’s total coastline measures 6,170 km (Panin et al. 2005), while its low and smooth coastline is estimated to be between 6,500 and 6,700 km, reaching 7,000 km if island coastlines are included (Lomonosov Moscow State University [MSU] and Russian Geograph- ical Society [RGS] 2017). There are 25 small and big rivers flowing into the Caspian Sea from Azerbaijan. The major rivers

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