Abstract Temperature plays an essential role in the ecology and biology of aquatic ecosystems. The use of dams to store and subsequently re-regulate river flows can have a negative impact on the natural thermal regime of rivers, causing thermal pollution of downstream river ecosystems. Autonomous thermal loggers were used to measure temperature changes downstream of a large dam on the Macquarie River, in Australia’s Murray-Darling Basin to quantify the effect of release mechanisms and dam storage volume on the downstream thermal regime. The magnitude of thermal pollution in the downstream river was affected by different release mechanisms, including bottom-level outlet releases, a thermal curtain (which draws water from above the hypolimnion), and spill-way release. Dam storage volume was linked to the magnitude of thermal pollution downstream; high storage volumes were related to severe thermal suppressions, with an approximate 10 °C difference occurring when water originated from high and low storage volumes. Downstream temperatures were 8 10 °C higher when surface releases were used via a thermal curtain and the spillway to mitigate cold water pollution that frequently occurs in the river. Demonstrating the effectiveness of engineering and operational strategies used to mitigate cold water pollution highlight their potential contribution to fish conservation, threatened species recovery and environmental remediation of aquatic ecosystems.

中文翻译：

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不同大坝泄洪机制和蓄水量对下游河流热态的影响

摘要 温度在水生生态系统的生态和生物学中起着至关重要的作用。使用大坝来蓄水并随后重新调节河流流量会对河流的自然热力状况产生负面影响，从而造成下游河流生态系统的热污染。自动热记录仪用于测量澳大利亚墨累-达令盆地 Macquarie 河上一座大坝下游的温度变化，以量化释放机制和大坝蓄水量对下游热状况的影响。下游河流的热污染程度受不同释放机制的影响，包括底层出口释放、热幕（从下层水层上方吸水）和溢洪道释放。大坝蓄水量与下游热污染的严重程度有关；高储存量与严重的热抑制有关，当水来自高储存量和低储存量时，会出现大约 10°C 的差异。当通过热幕和溢洪道使用地表释放来减轻河流中经常发生的冷水污染时，下游温度高出 8 ± 10 °C。展示用于减轻冷水污染的工程和运营策略的有效性，突出了它们对鱼类保护、受威胁物种恢复和水生生态系统环境修复的潜在贡献。当通过热幕和溢洪道使用地表释放来减轻河流中经常发生的冷水污染时，下游温度高出 8 ± 10 °C。展示用于减轻冷水污染的工程和运营策略的有效性，突出了它们对鱼类保护、受威胁物种恢复和水生生态系统环境修复的潜在贡献。当通过热幕和溢洪道使用地表释放来减轻河流中经常发生的冷水污染时，下游温度高出 8 ± 10 °C。展示用于减轻冷水污染的工程和运营策略的有效性，突出了它们对鱼类保护、受威胁物种恢复和水生生态系统环境修复的潜在贡献。