IMPROVING THE RELIABILITY AND EFFICIENCY OF OPERATION OF HYDRAULIC STRUCTURES OF THE ASTANA RESERVOIR THROUGH RECONSTRUCTION AND MODERNIZATION

Abstract

This paper examines ways to improve the reliability and operational efficiency of the Astana Reservoir hydraulic structures through reconstruction and modernization. The reservoir, commissioned in 1970, is a key facility for water supply to Astana and irrigation, and its earth dam has a total length of 1,154 m and a maximum height of 32 m. The study is based on the 2023 dam safety declaration and the 2025 verification report on overall stability and seepage strength. Numerical analyses were performed in PLAXIS 2D using the finite element method, the Mohr–Coulomb model, and a strength-reduction approach for five representative cross-sections. The assessment compared the existing condition with two reconstruction scenarios: installation of an anti-filtration screen, and installation of an anti-filtration screen combined with a cement grout curtain. The results showed that, despite a generally satisfactory visual condition, the existing dam configuration has unsafe seepage behavior and critical local instability in the most unfavorable section. Reconstruction measures significantly increased stability coefficients, reduced seepage gradients and velocities, and ensured filtration strength. The paper concludes that the most effective strategy is an integrated program combining anti-seepage reconstruction, renewal of nonfunctional monitoring systems, and digitalized water metering and operational control for long-term dam safety and management efficiency.