Abstract Reservoir storage helps manage hydrological variability, increasing predictability and productivity of water supply. However, there are inevitable tradeoffs, with control of high frequency variability coming at the expense of robustness to low frequency variability. Tightly controlling variability can reduce incentives to maintain adaptive capacity needed during events that exceed design thresholds. With multiple dimensions of change projected for many water supply systems globally, increased knowledge on the role of design and operational choices in balancing short-term control and long-term adaptability is needed. Here we investigated how the scale of reservoir storage (relative to demands and streamflow variability) and reservoir operating rules interact to mitigate shortage risk under changing supplies and/or demands. To address these questions, we examined three water supply systems that have faced changing conditions: the Colorado River in the Western United States, the Melbourne Water Supply System in Southeastern Australia, and the Western Cape Water Supply System in South Africa. Moreover, we parameterize a sociohydrological model of reservoir dynamics using time series from the three case studies above. We then used the model to explore the impacts of storage and operational rules. We found that larger storage volumes lead to a greater time before the shortage is observed, but that this time is not consistently used for adaptation. Additionally, our modeling results show that operating rules that trigger withdrawal decreases sooner tend to increase the probability of an adaptive response; the findings from this model are bolstered by the three case studies. While there are many factors influencing the response to water stress, our results demonstrate the importance of: i) evaluating design and operational choices in concert, and ii) examining the role of information salience in adapting water supply systems to changing conditions.

中文翻译：

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不断变化的条件下水库储存和操作规则之间的相互作用

摘要 水库蓄水有助于管理水文变化，提高供水的可预测性和生产力。然而，不可避免地存在权衡，以牺牲对低频可变性的鲁棒性为代价来控制高频可变性。严格控制可变性可以减少在超过设计阈值的事件期间维持所需适应能力的动机。由于全球许多供水系统预计会发生多方面的变化，因此需要更多地了解设计和运营选择在平衡短期控制和长期适应性方面的作用。在这里，我们研究了水库存储规模（相对于需求和流量变化）和水库运行规则如何相互作用以减轻供应和/或需求变化下的短缺风险。为了解决这些问题，我们研究了三个面临变化的供水系统：美国西部的科罗拉多河、澳大利亚东南部的墨尔本供水系统和南非的西开普供水系统。此外，我们使用来自上述三个案例研究的时间序列来参数化水库动力学的社会水文模型。然后，我们使用该模型来探索存储和操作规则的影响。我们发现，更大的存储量导致在观察到短缺之前的时间更长，但这段时间并没有一直用于适应。此外，我们的建模结果表明，触发退出的操作规则降低得越快，适应性反应的概率就会增加；该模型的结果得到了三个案例研究的支持。虽然影响对水资源压力的反应的因素有很多，但我们的结果表明：i) 协同评估设计和运营选择，以及 ii) 检查信息显着性在使供水系统适应不断变化的条件中的作用。