| Many of Australia's rivers are highly regulated, especially in the Murray-Darling Basin, with huge amounts of water stored in various weirs and the like, to be extracted for irrigation and other purposes. As a result, the water-flow regimes in these rivers have changed so that less water flows along them and it does so with the timing reversed, so that most water now flows in summer, when it is needed by agriculture, rather than when it would naturally flow in winter and spring. This has a detrimental effect along the course of the rivers. Many wetlands are now almost never filled, leading to loss of biodiversity. Environmental flows are managed changes to the pattern of the river flow, intended to either improve or at least maintain the health of a river. By providing extra water in the form of environmental flows, it is possible to protect these rivers and their ecosystems from further deterioration, and they are vital for populations of waterbirds and other birds which live near the rivers. Environmental flows reinvigorate the rivers' aquatic ecosystems, stimulating eucalypts to flower and waterbirds to breed. To be successful, an environmental flow must be provided when it is able to initiate the breeding of plants and animals downstream, and it needs to be big enough to flood wetlands associated with the river. These are especially important in times of drought, as the rivers are important resources, not just to farmers and townsfolk, but also to the wildlife which relies on them to survive. |
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Murray River at Hattah © Chris Tzaros
 Lewin's Rail, a rare bird that relies on wetlands for its survival © Chris Tzaros
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Birds 
