Water scarcity causes a series of eco-environmental problems, such as land salinization, biodiversity reduction and food crisis, which seriously restricts the sustainable development of the Aral Sea basin. In this study, a stepwise-cluster factorial analysis (SCFA) approach is proposed for assessing the effects of natural condition and human activity on the outflow of Syr Darya River (abbreviated as OSR) that has significant effects on the eco-environmental restoration of the Aral Sea. SCFA coupled stepwise cluster analysis and factorial analysis cannot only reflect the variability of outflow, but also identify the driving factors quantitatively. The results disclose that, in 1960–1991, the dominant factors (affecting the OSR) are upstream inflow (25.77%) > agricultural water use of Uzbekistan (7.21%) > industrial water use of Uzbekistan (4.53%) > agricultural water use of Kazakhstan (3.81%) > Precipitation (3.66%); interactions between upstream inflow and agricultural water use of Uzbekistan, Kazakhstan and Tajikistan and interactions between reservoir and evapotranspiration have the significant effects on the OSR. Results also indicate that, in 1992–2015, the dominant factors that affect the OSR are agricultural water use of Uzbekistan (23.31%) > agricultural water use of Kazakhstan (22.15%) > industrial water use of Uzbekistan (8.31%) > domestic water use of Kazakhstan (4.68%) > agricultural water use of Tajikistan (4.54%) > domestic water use of Uzbekistan (4.41%); the interactions between industrial water use and agricultural water use of Uzbekistan, Kazakhstan and Tajikistan and the interactions between reservoir and upstream inflow have the pivotal effects on OSR. In the future, when the agricultural water use of the basin decrease as 4% and the industry water use of Uzbekistan decrease as 2%, the OSR may recover to the middle level of 1970s. The results help identify the major factors affecting the outflow of Syr Darya River as well as seek an effective approach to restore the eco-environment of Aral Sea basin.

水资源短缺导致一系列生态环境问题，例如土地盐碱化，生物多样性减少和粮食危机，这严重限制了咸海流域的可持续发展。在这项研究中，提出了一种逐步聚类因子分析（SCFA）方法，用于评估自然条件和人类活动对锡尔河（Syr Darya）河（简称OSR）的流出的影响，该河道对该河的生态环境恢复具有重大影响。咸海。SCFA结合逐步聚类分析和因子分析不仅可以反映流出量的变化，而且可以定量地确定驱动因素。结果表明，在1960-1991年，主要因素（影响OSR）为上游流入量（25.77％）>乌兹别克斯坦的农业用水（7.21％）>乌兹别克斯坦的工业用水（4。53％）>​​哈萨克斯坦的农业用水（3.81％）>降水（3.66％）; 乌兹别克斯坦，哈萨克斯坦和塔吉克斯坦的上游流入量与农业用水之间的相互作用以及水库与蒸散量之间的相互作用对OSR有重要影响。结果还表明，在1992–2015年，影响OSR的主要因素是乌兹别克斯坦的农业用水（23.31％）>哈萨克斯坦的农业用水（22.15％）>乌兹别克斯坦的工业用水（8.31％）>生活用水哈萨克斯坦的使用量（4.68％）>塔吉克斯坦的农业用水量（4.54％）>乌兹别克斯坦的生活用水量（4.41％）；乌兹别克斯坦工业用水与农业用水之间的相互作用，哈萨克斯坦和塔吉克斯坦以及储层和上游流入之间的相互作用对OSR具有关键影响。将来，当流域的农业用水减少4％，乌兹别克斯坦的工业用水减少2％时，OSR可能恢复到1970年代中期。研究结果有助于确定影响锡尔河上游的主要因素，并寻求恢复咸海流域生态环境的有效途径。