Transboundary water cooperation in Central Asia links irrigation needs, energy security and environmental risk management. The study aimed to trace the evolution of water and environmental cooperation in Central Asia between 1991-2025, using Kyrgyzstan, Kazakhstan and Uzbekistan as examples. The study was conducted as a historical and comparative analysis based on intergovernmental agreements, coordination protocols, materials from regional institutions and project documents, comparing their content with the actual parameters of seasonal interaction and the environmental agenda. In the water-energy relationship between Kyrgyzstan and Kazakhstan, a shift in discharge regimes from irrigation to energy was recorded: between 1990 and 2000, the share of summer discharges decreased to about 45%, while winter discharges increased to about 55% (under the Soviet scheme, approximately 75% fell in summer and 25% in winter). In the trilateral coordination, in years of resource shortages, coordination shifted to a mode of specific parameters. In 2021, additional water volumes for irrigation were agreed at a level of about 700 million m3 compared to the previous year, and in 2025, decisions were made on energy supply for winter water conservation and summer water discharge. In terms of the environment, there has been a shift in focus towards monitoring water quality, land degradation and salinisation of irrigated areas, which reached 40-60% in regional assessments. These results can be used by the relevant water, energy and environmental authorities of Kyrgyzstan, Kazakhstan and Uzbekistan, regional coordination structures for transboundary waters, as well as international donors and project institutions to design procedures for seasonal coordination and reduction of environmental risks in transboundary river basins.
