River regulation alters the natural flow regime of streams with consequent impacts on terrestrial and aquatic habitats of the riparian zone. The severity of such impacts can be modulated by changing the redistribution rules at water intakes and reservoirs. Contrary to minimal-flow policies, non-proportional and proportional redistribution policies result in variable environmental flow releases, namely Dynamic Environmental Flows (DEFs), which improve the global (i.e., ecological and economic) efficiency of water use practice, e.g., for energy production. DEF assessment is based on different indicators. However, the choice and aggregation method of different hydrological and fish habitat indicators affects the assessment of the global power plant performance, i.e., the frontier of efficient solutions (sensu Pareto). This study investigates DEF assessment, and shows the extent to which the choice and method of aggregation of different indicators impacts the frontier of Pareto-efficient solutions. The findings are supported by six case studies of hydropower practice that differ in terms of river morphology, energy production amount and technique. The relative importance of several types of indicators is examined as is their influence on optimal and sustainable water allocation solutions that lie on the Pareto frontier. The analysis shows that DEFs arising from either proportional or non-proportional redistribution rules can positively impact strategies of sustainable management of freshwater resources.

中文翻译：

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水电和生态的（帕累托）最优和可持续水资源管理前沿

河流调节改变了溪流的自然流动状态，从而对河岸带的陆地和水生栖息地产生影响。这种影响的严重程度可以通过改变取水口和水库的再分配规则来调节。与最小流量政策相反，非比例和比例再分配政策导致可变的环境流量释放，即动态环境流量 (DEF)，它提高了用水实践的全球（即生态和经济）效率，例如，用于能源生产。DEF 评估基于不同的指标。然而，不同水文和鱼类栖息地指标的选择和聚合方法会影响对全球电厂性能的评估，即有效解决方案的前沿（sensu Pareto）。本研究调查了 DEF 评估，并显示了不同指标的选择和聚合方法对帕累托有效解决方案前沿的影响程度。研究结果得到了六个水电实践案例研究的支持，这些案例研究在河流形态、能源生产量和技术方面有所不同。研究了几种类型指标的相对重要性，以及它们对位于帕累托边界的最佳和可持续水资源分配解决方案的影响。分析表明，由比例或非比例再分配规则产生的 DEF 可以对淡水资源的可持续管理战略产生积极影响。研究结果得到了六个水电实践案例研究的支持，这些案例研究在河流形态、能源生产量和技术方面有所不同。研究了几种类型指标的相对重要性，以及它们对位于帕累托边界的最佳和可持续水资源分配解决方案的影响。分析表明，由比例或非比例再分配规则产生的 DEF 可以对淡水资源的可持续管理战略产生积极影响。研究结果得到了六个水电实践案例研究的支持，这些案例研究在河流形态、能源生产量和技术方面有所不同。研究了几种类型指标的相对重要性，以及它们对位于帕累托边界的最佳和可持续水资源分配解决方案的影响。分析表明，由比例或非比例再分配规则产生的 DEF 可以对淡水资源的可持续管理战略产生积极影响。