The eco-flow metrics (ecosurplus [ES] and ecodeficit [ED]) based on flow duration curves (FDCs) are currently less popular than other metrics used to assess the ecohydrological conditions of rivers. To fully utilize their application potential, the seasonal ES and ED are redefined based on discharge hydrographs (DHs) rather than their FDCs. The annual ES and ED are redefined as the sum of the four seasonal ES and ED values, respectively. The impact of reservoirs can be measured by the rate of increase of the cumulative seasonal eco-flows. Taking the seasonal EDs calculated by the 10% DH and 20% DH as the two threshold values, a risk evaluation method is proposed that classifies the seasonal ecohydrological conditions into four risk levels: no risk, low risk, moderate risk, and high risk. A daily discharge time series ranging from 1956 to 2015 in the Yellow River is used to perform a case study. The results showed that the Shannon diversity index (H) had a strong relevance to the annual ED. Riverine biodiversity was more sensitive to summer and autumn droughts than to floods. The Xiaolangdi Reservoir affected the seasonal eco-flows much more than the Sanmenxia Reservoir. The winter season is currently classified as having a high risk and should be given more attention by river managers in the future. After the ecological regulation measures are implemented in the future to improve the winter conditions, their effects can be re-evaluated by the above framework.

中文翻译：

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基于新生态流量评估水库对季节性生态水文条件影响的框架

基于流量持续时间曲线 (FDC) 的生态流量指标（生态盈余 [ES] 和生态赤字 [ED]）目前不如用于评估河流生态水文条件的其他指标流行。为了充分利用它们的应用潜力，季节性 ES 和 ED 是根据排放水位线 (DH) 而不是它们的 FDC 重新定义的。年度 ES 和 ED 分别重新定义为四个季节性 ES 和 ED 值的总和。水库的影响可以通过累积季节性生态流量的增长率来衡量。以10% DH和20% DH计算出的季节性EDs为两个阈值，提出了一种风险评价方法，将季节性生态水文状况分为四个风险等级：无风险、低风险、中风险和高风险。以黄河 1956 年至 2015 年的日流量时间序列进行案例研究。结果表明，香农多样性指数（H ) 与年度 ED 有很强的相关性。河流生物多样性对夏季和秋季的干旱比对洪水更敏感。小浪底水库对季节性生态流的影响远大于三门峡水库。冬季目前被列为具有高风险的季节，未来应引起河流管理人员的更多关注。在未来实施生态调节措施以改善冬季条件后，可以通过上述框架重新评估其效果。