The Syr Darya is Central Asia's main transboundary river shared by Kyrgyzstan, Uzbekistan, Tajikistan and Kazakhstan, yet basin-wide assessments that link climate, runoff, reservoir operation and water withdrawal in one spatial framework remain scarce. We built a harmonised hydroclimatic database for 2000–2025 and analysed it with Mann–Kendall, Sen's slope and Pettitt tests, SPI-12 and SPEI-12 drought indices, correlation and regularised regression, and GIS mapping in ArcGIS Pro. Near-term change to 2035 was estimated with a delta approach under SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5. Mean annual air temperature rose by 0.0329 °C yr⁻¹ (p = 0.003), with a change point around 2013, and potential evapotranspiration (PET) rose by 1.198 mm yr⁻¹ (p = 0.011). Precipitation (317.65 mm) and basin runoff (37.95 km³) showed no significant trend but strong interannual variability (runoff 27.64 km³ in 2007 vs 50.29 km³ in 2009). In the 2025 baseline, runoff was 33.25 km³ (−12.38 %), withdrawal was almost unchanged at 13.33 km³, and the withdrawal-to-runoff ratio reached 40.09 %. By 2035, runoff is projected at 37.85–36.48 km³ (−0.25 % to −3.87 % relative to 2000–2024), snowfall declines by 8–16 % and summer climatic water balance falls to −506.42 mm under SSP5-8.5. Water-supply maps show a persistent upstream–downstream gradient, with the lower reaches and the summer irrigation season the most exposed. Water stress in the basin is therefore driven less by falling precipitation than by rising atmospheric demand acting on near-constant withdrawals.
Rising Atmospheric Demand and Water Stress in The Syr Darya River Basin: A GIS-Based Assessment Of 2000–2025 Trends and SSP Scenarios To 2035
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References
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