The Kara-Bogaz-Gol (KBG) is a large, shallow lagoon of the Caspian Sea, normally about 18 200 km2 (7,000 square miles) and just a few meters deep. The Caspian Sea's changing water level has been a concern for almost a century, but especially since the 1970s. Since the KBG's water flows in from the Caspian, the Caspian's fluctuations have affected the KBG dramatically. In 1980, in response to the rapidly dropping sea level, a dam was constructed to prevent water from flowing into the shallow and restricted Kara-Bogaz-Gol basin, resulting in the drying up of the lagoon. The dam was intended to prevent Caspian Sea water from flowing into the Kara-Bogaz-Gol, which the builders of the dam believed was acting as an evaporation pond and contributing to the lowered water levels. The dam created environmental problems and was demolished in 1992.