Dam construction and operation are known to alter the hydrology of rivers and degrade riverine ecosystems. In recent decades, the call to reverse these negative impacts by re-operating dams has become stronger. Dams can support riverine ecosystems by releasing environmental flows (e-flows). Unfortunately, despite the development of numerous methodologies to determine e-flows and optimise dam releases, actual implementation has not followed suit. Integrating e-flow requirements in the design of new dams is relatively easier than changing operations of existing dams; however, re-operating existing dams is essential to restore ecosystems and ecosystem services that have already been affected by the construction and operation of dams. This study provides insights into how e-flows evolve from recommendation to practice through a systematic literature review on practical experiences to integrate e-flows in dam operations. Sixty-nine cases of successful dam re-operation have been identified, ranging from the well-documented case of the Glen Canyon Dam in the United States to less known cases such as the Katse Dam in Lesotho. We find that the most important factors that facilitate the successful implementation of e-flows are the existence of e-flows legislation or policy, the development of a research base in the form of an environmental impact study, and then flow experimentation. Illustrations of the important role of collaboration between various stakeholders and set timelines for implementation of recommendations are also given. These insights will inform how existing dams can be re-operated and governed more equitably and sustainably for both humans and the environment.

中文翻译：

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为环境流量重新运营大坝：从建议到实践

众所周知，大坝的建设和运营会改变河流的水文和河流生态系统的退化。近几十年来，通过重新运营大坝来扭转这些负面影响的呼声越来越高。大坝可以通过释放环境流量（电子流量）来支持河流生态系统。不幸的是，尽管开发了多种方法来确定电子流量和优化大坝泄水，但实际实施并未效仿。在新大坝的设计中整合 e-flow 要求比改变现有大坝的操作相对容易；然而，重新运营现有大坝对于恢复已经受到大坝建设和运营影响的生态系统和生态系统服务至关重要。本研究通过对将电子流整合到大坝运营中的实践经验的系统文献综述，提供了关于电子流如何从建议演变为实践的见解。已经确定了 69 个成功的大坝重新运营案例，从美国格伦峡谷大坝的充分记录案例到莱索托的 Katse 大坝等鲜为人知的案例。我们发现，促进 e-flows 成功实施的最重要因素是 e-flows 立法或政策的存在，以环境影响研究的形式发展研究基地，然后是流量实验。还举例说明了不同利益相关者之间合作的重要作用以及为实施建议设定的时间表。