Kara-Bogaz-Gol Bay

Abstract

Kara-Bogaz-Gol Bay is a large lagoon east of the Caspian Sea and normally covers an area around 18000 km² and is only a few meters deep. It is several meters lower than the Caspian Sea, so water flows from the Caspian Sea through a narrow strait into the bay, where it evaporates. Kara-Bogaz-Gol Bay is one of the saltiest bodies of water in the world: salt concentrations up to 350 g L⁻¹ have been documented. The salt in this natural evaporative basin has been used commercially since at least the 1920s. In March 1980, in order to restrict the losses of the Caspian waters and to decelerate the fall of the Caspian water level, which in 1977 was the lowest at any time over the last 400 years (−29 m), the Kara-Bogaz-Gol Strait was dammed. In response to this anthropogenic intervention, the bay had already dried up completely by November 1983. In 1992, the dam was destroyed. Kara-Bogaz-Gol Bay has been filling up with Caspian water at a rate of 1.7 m yr⁻¹ up to 1996 as observed by the TOPEX/Poseidon altimetry mission. Since then, Kara-Bogaz-Gol Bay level evolution with characteristic seasonal oscillations and a decreasing tendency with a rate of 6 cm yr⁻¹ has been similar to that of the Caspian Sea.