Abstract
<jats:p>The problems of developing the water supply system (WSS) of the Republic of Kazakhstan in the transboundary Shu-Talas basin are formulated, and the goals and objectives of modeling are defined. As a scientific method for achieving the objectives, a system analysis methodology is proposed, which considers the problem of sustainable water supply as a complex system with its inherent properties of multidimensionality, conflict, and uncertainty. The technology of mathematical dynamic-stochastic modeling of complex systems is used as a tool for system analysis, which is a numerical method for conducting computational experiments on a computer with mathematical models that simulate the behavior of real objects over time during a given period. A description of the chorological structure of the water supply systems of the Shu and Talas River basins is given, and a logical-mathematical description of the WSS is provided. Due to the versatility of the underlying methodological approaches and the use of formalized mathematical models, the developed methodology has a high degree of adaptability and scalability. The methodology can be used to assess water use scenarios, identify potential conflicts of interest between water users, analyze risks, and justify agreed interstate decisions aimed at ensuring sustainable water management development and strengthening regional water security.</jats:p>