Simulation of surface water flow and temperature under a non-stationary, anthropogenically impacted climate is critical for water resource decision makers, especially in the context of environmental flow determination. Two climate change scenarios were employed to predict streamflow and temperature: RCP 8.5, the most pessimistic with regards to climate change, and RCP 4.5, a more optimistic scenario where greenhouse gas emissions peak in 2040. Two periods, 2018–2050 and 2051–2100, were also evaluated. In Canada, a number of modelling studies have shown that many regions will likely be faced with higher winter flow and lower summer flows. The CEQUEAU hydrological and water temperature model was calibrated and validated for the Wilmot River, Canada, using historic data for flow and temperature. Total annual precipitation in the region was found to remain stable under RCP 4.5 and increase over time under RCP 8.5. Median stream flow was expected to increase over present levels in the low flow months of August and September. However, increased climate variability led to higher numbers of periodic extreme low flow events and little change to the frequency of extreme high flow events. The effective increase in water temperature was four-fold greater in winter with an approximate mean difference of 4 °C, while the change was only 1 °C in summer. Overall implications for native coldwater fishes and water abstraction are not severe, except for the potential for more variability, and hence periodic extreme low flow/high temperature events.

中文翻译：

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环境流量和未来气候变化背景下的水温和水文建模：威尔莫特河案例研究（加拿大）

在非平稳、人为影响的气候下模拟地表水流量和温度对于水资源决策者至关重要，尤其是在确定环境流量的背景下。使用两种气候变化情景来预测流量和温度：RCP 8.5，对气候变化最悲观的情景，以及 RCP 4.5，一种更乐观的情景，其中温室气体排放量在 2040 年达到峰值。 两个时期，2018-2050 和 2051-2100 ，也进行了评价。在加拿大，多项建模研究表明，许多地区可能会面临更高的冬季流量和更低的夏季流量。CEQUEAU 水文和水温模型针对加拿大威尔莫特河使用流量和温度的历史数据进行了校准和验证。发现该地区的年总降水量在 RCP 4.5 下保持稳定，在 RCP 8.5 下随着时间的推移而增加。在 8 月和 9 月的低流量月份，中值流量预计将高于当前水平。然而，气候变率的增加导致周期性极端低流量事件的数量增加，而极端高流量事件的频率几乎没有变化。冬季水温的有效升幅是 4 倍，平均差异约为 4°C，而夏季的变化仅为 1°C。对本地冷水鱼类和取水的总体影响并不严重，除了可能发生更多变化，从而导致周期性的极端低流量/高温事件。在 8 月和 9 月的低流量月份，中值流量预计将高于当前水平。然而，气候变率的增加导致周期性极端低流量事件的数量增加，而极端高流量事件的频率几乎没有变化。冬季水温的有效升幅是 4 倍，平均差异约为 4°C，而夏季的变化仅为 1°C。对本地冷水鱼类和取水的总体影响并不严重，除了可能发生更多变化，从而导致周期性的极端低流量/高温事件。在 8 月和 9 月的低流量月份，中值流量预计将高于当前水平。然而，气候变率的增加导致周期性极端低流量事件的数量增加，而极端高流量事件的频率几乎没有变化。冬季水温的有效升幅是 4 倍，平均差异约为 4°C，而夏季的变化仅为 1°C。对本地冷水鱼类和取水的总体影响并不严重，除了可能发生更多变化，从而导致周期性的极端低流量/高温事件。冬季水温的有效升幅是 4 倍，平均差异约为 4°C，而夏季的变化仅为 1°C。对本地冷水鱼类和取水的总体影响并不严重，除了可能发生更多变化，从而导致周期性的极端低流量/高温事件。冬季水温的有效升幅是 4 倍，平均差异约为 4°C，而夏季的变化仅为 1°C。对本地冷水鱼类和取水的总体影响并不严重，除了可能发生更多变化，从而导致周期性的极端低流量/高温事件。