基于Mann-Kendall检验和模糊综合评价法的黄河三盛公断面2011-2024年水质变化趋势分析OA

The Sanshenggong Section is a pivotal hydrological monitoring and control section on the Yellow River,where water quality directly affects the ecological security and sustainable utilization of water resources in the middle and lower reaches.Using water quality monitoring data from this section between 2011 to 2024,this study employed the Mann-Kendall test to identify abrupt change points in water quality trends.A combined evaluation framework was then employed,integrating the Single Factor Evaluation Method and a Fuzzy Comprehensive Evaluation Method,with weights by both the CRITIC and Entropy,to systematically assess the evolutionary trajectory of water quality.The Mann-Kendall test identified 2013 and 2019 as water quality abrupt change points.Water quality showed non-significant improvement during 2013-2015,but shifted to significant improvement after 2016.Single-factor evluation indicated that total phosphorus(TP)was the main over-standard factors during 2011-2012,and a continuous decline in TP drove the water quality category to improve from Grade III to within the range of Grade II standard limits in 2013.The combined weighting method highlighted the permanganate index as the primary pollutant,with a weight of 28.96％;its declining concentration served as the core driver of water quality improvement.Fuzzy evaluation revealed that the membership value of Grade III water dropped to zero in 2013,indicating a stable shift towards superior water quality.However,a phased rebound in the membership value of Grade II water suggests at a potential risk of quality regression.This study demonstrates that the Mann-Kendall test,single factor evluation and the improved fuzzy comprehensive evaluation method can effectively capature the water quality changes at the monitoring section,thereby providing a scientific basis for precise water quality management and ecological protection in the middle and upper reaches of the Yellow River.