为评估南水北调东线平原水库生态服务效益，基于生态系统服务理论，综合影子工程法、意愿支付法等方法 提出服务价值核算标准；将粗糙集理论和层次分析法作为权重确定方法，进一步评估平原水库对地区人类福祉的 贡献；以大屯水库为实际案例开展应用研究。结果表明：平原水库具备洪水调蓄、固碳释氧、水源涵养等共计 12 项生态服务功能；以水量供给为纽带，为地区带来经济、生态、社会效益，促进地区福祉提升；大屯水库具备 8 项 服务功能，2021 年时该水库总服务价值达 2.365 亿元，供给服务价值是其主要构成，该水库为地区提供的经济、生 态和社会效益各占 50%、41% 和 9%。研究成果在指导管理机构实现科学管理，促进水利工程更好地实现生态价 值方面具有实践意义。

The plain reservoir is an important part of the Eastern Route of the South-to-North Water Transfers Project, supplying water resources for residents, industrial production, and agricultural irrigation, and also providing ecological water replenishment for natural water systems such as mudflats, wetlands, and rivers. Evaluating the ecological service benefits of plain reservoirs will not only help management organizations fully understand the reservoirs' operational status but also guide them in improving the ecological functions, thus promoting human well-being in the service areas. To construct an ecological benefit assessment framework consistent with the engineering characteristics, various calculation methods were synthesized to study the ecological functions and comprehensive benefits of plain reservoirs.The ecological service functions of the plain reservoir were sorted out based on the ecosystem services theory. The accounting standards of ecological service functions' value were determined by various methods such as shadow engineering, market value, willingness-to-pay and so on. To further explore the comprehensive benefits provided by plain reservoirs, the interactive relationship between the service functions of the plain reservoir and the ecological and socio-economic systems of the service areas was analyzed. Using rough set theory and hierarchical analysis as weight determination methods, an assessment model was further built. The Datun Reservoir in Dezhou, Shandong Province was taken as a practical case to carry out the applied research.It was found that: The overall service value of Datun Reservoir shows a general upward trend between 2015 and 2021, peaking in 2018, and the total service value reached 236.493 million yuan in 2021. The value of regulating, supplying, supporting, and cultural services has the largest share of supplying services and fluctuates the most due to its relation to water allocation, reaching 117.654 million yuan in 2021, up 88.363 million yuan compared to 29.291 million yuan in 2015. The smallest cultural services value was 21.003 million yuan in 2021. The comprehensive benefits brought by Datun Reservoir to the human well-being in the service area mainly dominated by ecological and economic benefits. The total benefits in 2015 and 2021 were 44.476 and 85.618 million yuan, respectively. The proportion of economic, ecological, and social benefits, showed a stabilizing trend, gradually remaining at 50%, 41%, and 9%.An accounting standard was proposed for the ecological service value of plain reservoirs and ideas were provided for further assessing the comprehensive benefits of human well-being brought by reservoirs to the region, which not only helps to intuitively reflect the operational status of plain reservoirs but also has practical significance in promoting the realization of the functional value and scientific management.