Investigating and evaluating the dynamics of change in water resources of the Aydar-Arnasay Lake system in Uzbekistan

The Aydar-Arnasay Lake System (AALS) is located in the middle of the Syrdarya River, to the south of the Chardara Reservoir, and in Jizakh and Navoi provinces of the Republic of Uzbekistan, adjacent to the low plain of South Mirzachul. Currently, the AALS has a significant impact on the regional ecosystem and socio-economic conditions of the region. Studying and evaluating the AALS hydrology, the water volume, surface area, and variability of water levels altogether play an important role in the development of fisheries and ecotourism in the region. However, in the past studies, the dynamic changes in the volume, area, and water levels of the AALS have not been investigated through up-to-the-date geo-information systems (GIS), requiring additional research to formulate a proper methodology considering the potential aspects of GIS. Therefore, this paper aims at analyzing the dynamics of changes in the water level, surface area, and water volume of the AALS by using GIS technologies within 1993–2017 years. During the period from 1993 to 2006, the water level and the surface area of the AALS steeply increased and remained stable with negligible positive and negative fluctuations in the rest of the experimental years. These findings were successfully tested and validated by ANOVA, indicating an exceptionally low F-significance of 0.0008. According to the AALS’s water volume dynamics, we investigated here the role of two factors: anthropogenic—the outflow water discharge from the reservoir located in the neighboring country; and natural—the amount of perennial precipitation. Consequently, we ascertained that the role of precipitation as a natural driving factor in expansion is majorly less than the outflow water from the reservoir, despite having a gradual increase in the perennial precipitation trend. As we assume that the hydrological characteristics of the AALS are strongly dependent on air temperature and the amount of precipitation due to the extreme restriction of outflow water discharge from the reservoir, thus the establishment of proper GIS-tracking and monitoring methodology is recommended to early warn the potential minor changes which could become severe in the near future.