How has water diversion from the Volga River contributed to changes in the Caspian Sea level?

Water diversion from the Volga River system, primarily for irrigation and industrial use, has significantly impacted the Caspian Sea level.12

The construction of extensive dams and reservoirs along the Volga has fundamentally altered the river's natural flow, leading to water loss through impoundment and increased evaporation. By reducing the volume of water that reaches the river's mouth, these human-made changes have diminished the total discharge into the Caspian Sea. This reduction in river influx, when combined with climatic factors that increase evaporation, has been a contributing factor to the long-term decline in the sea's water level, most notably observed between 1930 and 1977.132

While climatic shifts remain the primary driver of the sea's long-term fluctuations, the diversion and management of Volga waters have amplified these hydrologic imbalances, necessitating ongoing efforts to mitigate such human-induced environmental consequences.12