中文摘要：

本文提出基于水文循环分析的生态需水量计算流程图和方法，即通过野外现场查勘和室内遥感分析，总结研究区生态需水特征，运用环境同位素技术分析水分来源和河道内外水力补给关系，确定明确的生态保护目标，选定合适的生态需水估算方法并进行计算。最后对雅砻江流域河道内外的生态需水量进行计算。结果表明，雅砻江河道径流主要受大气降水补给，地下水单向补给河道水；河道内外生态保护目标分别为保持当前植被面积不减少和保证优势鱼类生长繁殖期最低生境条件；天然降水即可满足草地林地的生态需水要求。雅砻江热巴坝址处最小生态流量范围为36．3～46．8m^3／s。

英文摘要：

A method for evaluating the ecological water requirement based on hydrological cycle analysis is suggested and the flow chart for calculation is designed. Field investigation and remote sensing interpretation are carried out to sum up the characteristics of ecological water demand. The amount of water sources and the hydraulic interaction among precipitation, surface water and groundwater are analyzed by applying environmental isotope technology. According to the objectives of ecological protection the suitable method for evaluating ecological water demand can be selected based on the comparison of different approaches. The proposed requirement in Yalong River basin. The result shows method is applied to calculate the ecological water that the river runoff of Yalong River is obtained from precipitation and the stream flow is supplied by groundwater unilaterally. The objectives of ecological protection for habitat conditi requirements. outside and inside of the river are maintaining the current vegetation area and satisfying the ons of growth and breeding of fishes. The current precipitation can sufficiently fulfill these The minimum stream discharge for ecological requirement at the dam site of Reba Hydro Project is in the range of 36.3m^3/s to 46.8m^3/s.