Abstract

Large multi-purpose reservoirs serve not only to generate hydropower but to supply water for agricultural irrigation, animal and human consumption and to provide flood control. One of the key factors affecting physical functioning and deteriorating aquatic ecosystems in reservoirs is climate change. For instance, increases in water temperature accelerate chemical reaction rates, decomposition rates and oxygen demand at the water-sediment interface. Earlier thermal stratification onset, and longer and more intense reservoir thermal stratification are all consequences of global warming. Such disruptions in thermal stratification have been associated with reductions in hypolimnion dissolved oxygen, increasing anoxia events and enhancing reservoir eutrophication. In this research paper, we implement the 2 D hydrodynamics and water quality model, CE-QUAL-W2, to investigate the effects of climate change and streamflow scenarios on the thermal structure of Lake Diefenbaker, a large, multipurpose reservoir, located in Saskatchewan, Canada. Model results indicate that meteorological variability will dictate a nonlinear increase in reservoir water temperature in the coming decades, where larger increases in water temperature will occur during summer and fall in the upper layers. Also, decreases in reservoir streamflows will reduce water temperature at intermediate layers during summer and fall. Our model can be used as a tool to mitigate and manage the effects of climate change on the reservoir water quality.

摘要

大型多功能水库不仅用于发电，还用于农业灌溉、动物和人类消费以及防洪。影响水库物理功能和恶化水库生态系统的关键因素之一是气候变化。例如，水温升高会加速水-沉积物界面的化学反应速率、分解速率和需氧量。更早的热分层开始，以及更长和更强烈的储层热分层都是全球变暖的后果。热分层的这种破坏与水下溶解氧的减少、缺氧事件的增加和水库富营养化的增加有关。在这篇研究论文中，我们实施了二维流体动力学和水质模型，CE-QUAL-W2，研究气候变化和水流情景对位于加拿大萨斯喀彻温省的大型多功能水库迪芬贝克湖热结构的影响。模型结果表明，气象变化将决定未来几十年水库水温的非线性增加，其中水温将在夏季和上层秋季出现更大的增加。此外，在夏季和秋季，水库流量的减少将降低中间层的水温。我们的模型可用作减轻和管理气候变化对水库水质影响的工具。模型结果表明，气象变化将决定未来几十年水库水温的非线性增加，其中水温将在夏季和上层秋季出现更大的增加。此外，在夏季和秋季，水库流量的减少将降低中间层的水温。我们的模型可用作减轻和管理气候变化对水库水质影响的工具。模型结果表明，气象变化将决定未来几十年水库水温的非线性增加，其中水温将在夏季和上层秋季出现更大的增加。此外，在夏季和秋季，水库流量的减少将降低中间层的水温。我们的模型可用作减轻和管理气候变化对水库水质影响的工具。