Background

Climate change induced a rise in surface water temperature and a prolongation of summer stratification in drinking water reservoirs. Stratification and temperature are important factors for drinking water production because they influence bio-geo-chemical processes and thus affect water quality. Most drinking water reservoirs have outlet structures that allow water to be withdrawn from different depths at variable rates. The thermal structure of these reservoirs can thus be managed actively by means of dynamic withdrawal schemes.

Results

We employed the hydro-physical General Lake Model to simulate the effects of different withdrawal strategies on temperatures and stratification in three German reservoirs. In particular, we assessed the potential of depth- and time-variable withdrawal to mitigate the impacts of climate change. We found that deep water temperatures (25 m below surface) and the end of summer stagnation are strongly controlled by the withdrawal regime. Specifically, the simulated impact of the withdrawal scheme was of the same order of magnitude as the observed impact of climate change over the last 30 years. However, the end of ice cover, the onset of summer stagnation, and near-surface temperatures (3 m depth) were rather insensitive to altered withdrawal strategies.

Conclusions

Our results suggest that an adaption of withdrawal depth and timing will partly compensate for the effects of climate change. Dynamic withdrawal should thus be considered as an integral part of future reservoir management strategies.

中文翻译：

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管理饮用水水库的气候变化：动态取水策略的潜力和局限性

背景

气候变化导致饮用水水库的地表水温度升高和夏季分层延长。分层和温度是饮用水生产的重要因素，因为它们影响生物地球化学过程，从而影响水质。大多数饮用水水箱都具有出口结构，该结构允许以不同的速率从不同深度取水。因此，这些储层的热结构可以通过动态取水方案进行主动管理。

结果

我们采用了水力物理通用湖模型来模拟三个德国水库中不同抽水策略对温度和分层的影响。尤其是，我们评估了深度和时变撤离缓解气候变化影响的潜力。我们发现深水温度（地表以下25 m）和夏季停滞的结束受到撤水制度的强烈控制。具体而言，退出计划的模拟影响与过去30年观察到的气候变化影响具有相同数量级。但是，冰盖的结束，夏季停滞的开始以及近地表温度（3 m深度）对改变撤离策略不敏感。

结论

我们的结果表明，适应撤离深度和时机将部分补偿气候变化的影响。因此，动态取水应被视为未来储层管理策略的组成部分。