Abstract
The article discusses modern approaches to assessing and analyzing the water balance of the Bartogai Reservoir, located in the Shelek River basin. The Bartogai Reservoir is located in the Bartogai tract, 175 km from Almaty and 70 km from the village of Shelek. The total design capacity of the reservoir is 320 mln.m3, the dead volume is 70 mln.m3, the useful volume is 250 mln.m3, the dam height is 60 m, the dam length is 325 m, and the length of the connecting dams is 250 m. A comprehensive analysis of the main elements of the balance was conducted, including inflow, water withdrawals for economic needs, evaporation, filtration losses, and the operating mode of hydraulic structures. The balance covers the period from January to December 2024, with the result as of January 1, 2025. The volume of water at the beginning of 2024 was 184.0 million m³. During the year, the volume fluctuated: the maximum was 296.9 mln.m3 (May–June), and the minimum was 156.1 mln.m3 (November). At the end of the year (January 1, 2025), it was 186.3 mln.m3. By the end of the year, the reservoir level had almost returned to its initial value (an increase of 2.3 mln.m3). Based on the collected and processed hydrological data, the effectiveness of current water use was assessed and key problems related to uneven water supply and increasing anthropogenic pressure were identified. The results of the study can be used to optimize reservoir operation modes, improve water supply reliability, and conduct long-term planning in the region's water resources sector.