Response of the water level of the Balkash Lake to the distribution of meteorological and hydrological droughts under the conditions of climate change

Hydrological droughts occur due to a variety of hydrometeorological phenomena, such as a lack of precipitation, reduced snow cover, and high evaporation. The values of these factors vary depending on the climate and the severity of drought events. Droughts caused by a lack of precipitation and continuing in the warm season have a longer periodicity. This important statement raises the question of whether climate change may exacerbate the phenomenon of drought. Therefore, understanding the changes in the formation of hydrological droughts is key to foreseeing possible changes in the future. This scientific study analyses the spread of hydrometeorological droughts in the Ile-Balkash basin using standardized precipitation indices and the drought index of river runoff. Lake Balkash plays an important role in the hydrological cycle and is a valuable freshwater resource, especially in dry years. Prolonged droughts in the area have serious consequences, such as deterioration of water quality and loss of wetlands, which are important to the ecological system and migratory birds. The analysis shows that during the period of instrumental observations, several extreme hydrological droughts were observed in this area (1943–1946, 1973–1975, and 1983–1987), which emphasizes the relevance and importance of scientific research on the problem of drought.