THE IMPACT OF CASPIAN SEA LEVEL DROP ON GROUNDWATER LEVEL FLUCTUATIONS (CASE STUDY OF THE NABRAN COAST)

Abstract

The water balance of the Caspian Sea (lake), considered the largest enclosed body of water in the world and distinguished by its hydrometeorological and oceanographic characteristics, is formed by river water, precipitation, and, to some extent, groundwater. As an enclosed body of water, its water level rises due to inflowing rivers, but it partially loses water volume due to evaporation. In recent years, the Caspian Sea has been experiencing a steady decline in water level. These changes in the sea are consequence of global climate change and its impacts on the Caspian region. Data from sea level monitoring conducted from 1837 to the present show that similar fluctuations in the Caspian Sea level are observed periodically, and even the current level (approximately -29 m) can be considered the second most critical. The first critical drop in the last 200 years was recorded in 1977 and amounted to -28.92 m. If we look at the history of the Caspian Sea, we see that during these years, a period of sharp decline in its level was observed. This period spans 1930–1977, after which a 2.5-meter rise in the Caspian Sea was observed over a 16-year period (1978–1995).