The Han River-to-Wei River Water Transfer (HWWT) Project not only brings evident economic benefits to the water-receiving areas but it also generates ecological flow value (EFV) by indirectly supplementing river flows. However, the EFV resulting from water transfer is often overlooked due to its indirect nature, and traditional methods tend to overestimate it due to a lack of consideration of value growth thresholds. This paper proposes a research system to address these issues, scientifically quantifying the EFV increment after water transfer. Taking the Xianyang–Lintong river segment in the water-receiving area of the HWWT as an example, we present a holistic approach guided by river ecological issues to determine the suitable ecological flow (SEF) for the river, using it as the growth threshold for EFV. Subsequently, based on water resource allocation, changes in river flow and their relative percentages to SEF (SEF satisfaction) before and after water transfer were analyzed. Finally, an ecological value model based on SEF was employed to estimate changes in river EFV. The results indicate that the distribution of SEF varied throughout the year, correlating with the monthly water requirements of key ecological functions in the river. After water transfer, SEF satisfaction notably improved across all months except excessively wet periods. In drier years, river EFV increased significantly, reaching 31.31% at 95% flow frequency. The water purification, hydrologic cycle, sediment transport and biological diversity, contributed the most to EFV. This study provided new insights and methodologies for assessing EFV increments and formulating ecological compensation standards in the water-receiving areas after water transfer.

汉江至渭河调水 （HWWT） 项目不仅为受水区带来了明显的经济效益，而且还通过间接补充河流流量产生了生态流量价值 （EFV）。然而，由于水转移产生的 EFV 的间接性质，经常被忽视，而传统方法由于缺乏对价值增长阈值的考虑，往往高估了它。本文提出了一种研究系统来解决这些问题，科学地量化了调水后的 EFV 增量。以 HWWT 受水区咸阳—临潼河段为例，我们提出了一种以河流生态问题为指导的整体方法，以确定河流的适宜生态流量 （SEF），并将其作为 EFV 的增长阈值。随后，基于水资源分配，分析了调水前后河流流量的变化及其对 SEF 的相对百分比（SEF 满意度）。最后，采用基于 SEF 的生态价值模型估计河流 EFV 的变化。结果表明，SEF 的分布全年变化，与河流中关键生态功能的每月需水量相关。输水后，除过度潮湿时期外，所有月份的 SEF 满意度都显著提高。在较干旱的年份，河流 EFV 显著增加，在 95% 的流量频率下达到 31.31%。水净化、水文循环、沉积物运输和生物多样性对 EFV 的贡献最大。本研究为评估调水后受水区 EFV 增量和制定生态补偿标准提供了新的见解和方法。