Risk Assessment and Prediction of Reclaimed Water Utilization in Yuyao City, China

Reclaimed water can alleviate urban water scarcity, but its utilization involves risks across production, transmission, utilization, and management. This study established an 18-indicator assessment system for Yuyao City. Analytic hierarchy process (AHP) and entropy weights were combined using a game-theory-based procedure, while a fuzzy matter-element model assessed historical risks during 2020–2023. Nonlinear autoregressive models generated three output settings for seven time series, forming 2187 nonprobabilistic input combinations for 2025, 2030, and 2035. Historical risk remained within the medium-risk class but declined annually. Production and utilization received the largest criterion weights (0.352 and 0.336, respectively). The proportion of reclaimed water usage, reclaimed water utilization rate, green space rate in built-up areas, investment proportion, and industrial water reuse rate received the highest indicator weights. Across the constructed combinations, risk indices ranged from 0.361 to 0.469 in 2025, 0.376 to 0.420 in 2030, and 0.286 to 0.339 in 2035, with arithmetic means of 0.413, 0.395, and 0.312, respectively. All ranges remained within the medium-risk class. Further risk reduction requires coordinated improvements in production capacity, pipeline coverage, utilization, and institutional support. Future studies should use longer time series, time-ordered validation, and sensitivity tests of weights and thresholds.