ABSTRACT River regulation has degraded the River Murray’s riverine ecosystems. Environmental flows are now being delivered to restore these ecosystems to a more natural, pre-regulation state. To guide the development of environmental flow recommendations, I calculated 28 Environmental Flow Components for the River Murray in South Australia, comparing simulated flow data for natural and present conditions. Regulation has caused complex changes to the rivers’ hydrology. Under present conditions, the inter-annual frequency of extreme low flows (<4150 ML/day) and high flow pulses (15,000–55,000 ML/day) has increased, whilst for small floods (55,000–100,000 ML/day) and large floods (>100,000 ML/day) frequency has declined. The magnitude of low flows (4150–15,000 ML/day) has been reduced for all months, and extreme low flows and high flow pulses occur later in the year. The duration of high flow pulses, and both small and large floods, have also declined under present conditions. Restoring more natural extreme low flows and high flow pulses will require new events to be engineered, whilst environmental water can be used to enhance monthly low flows and small floods. In addition to providing environmental flows, changes to river operations, particularly instituting weir pool manipulation, is required to maximise ecological outcomes.

中文翻译：

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将环境流量分量方法应用于南澳大利亚墨累河

摘要 河流调节使墨累河的河流生态系统退化。现在正在输送环境流量，以将这些生态系统恢复到更自然的、监管前的状态。为了指导环境流量建议的制定，我计算了南澳大利亚墨累河的 28 个环境流量分量，比较了自然条件和当前条件下的模拟流量数据。监管给河流的水文带来了复杂的变化。在目前条件下，极低流量（<4150 ML/天）和高流量脉冲（15,000-55,000 ML/天）的年际频率增加，而小洪水（55,000-100,000 ML/天）和大洪水的年际频率增加(>100,000 ML/天) 频率已经下降。所有月份的低流量（4150–15,000 毫升/天）的幅度都已降低，极低流量和高流量脉冲发生在今年晚些时候。在目前的条件下，高流量脉冲的持续时间以及小洪水和大洪水的持续时间也有所下降。恢复更自然的极低流量和高流量脉冲将需要设计新的事件，而环境水可用于增强每月的低流量和小洪水。除了提供环境流量外，还需要改变河流运营，特别是建立堰池操纵，以最大限度地提高生态结果。而环境水可用于增强每月的低流量和小洪水。除了提供环境流量外，还需要改变河流运营，特别是建立堰池操纵，以最大限度地提高生态结果。而环境水可用于增强每月的低流量和小洪水。除了提供环境流量外，还需要改变河流运营，特别是建立堰池操纵，以最大限度地提高生态结果。