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ARIDFLO Environmental Flow Requirements of Arid Zone Rivers with Particular Reference to the Lake Eyre Drainage Basin

Department of Water, Land and Biodiversity Conservation for Department of the Environment and Water Resources, 2007

Costelloe J.F., Hudson P.J., Pritchard J.C., Puckridge J.T., Reid J.R.W.

About this report

The rivers of the Lake Eyre Basin (LEB) are among the world's last large rivers to remain unregulated and minimally human-impacted and include such Australian folklore icons as the Cooper and Diamantina. They are characterised by catchments that are almost entirely within the arid zone, having low gradients throughout their course, endorheic drainage (internally draining rather than reaching the sea), wide floodplains in the mid-lower reaches, large transmission losses, and extremely high flow variability. This extreme flow variability means that rivers naturally fluctuate between an inland sea of floodwaters and a handful of isolated wetlands or waterholes. Thus at any given time there is a mosaic of different aquatic habitats in the LEB, and over time there is many a healthy ecological dynamism. This contrasts strongly with the ecological stagnation and decline of regulated rivers.

Although LEB aquatic ecosystems are currently in good health, an improved understanding of the ecological functioning of these rivers is critical to balance their environmental needs against current and future demands on their waters. However, little is currently known of the basic biology and hydrology, let alone the complex hydrology-ecology relationships in these remote rivers. Some rivers are minimally gauged but most remain ungauged, and very little biological work has been carried out over a broad scale. The ARIDFLO project was devised to help address this paucity of knowledge and to allow qualitative prediction of the impacts that upstream water resource proposals would likely have on fundamental ecosystem processes. The results of this project should also be useful in the management, planning and monitoring of existing or future water use projects in arid and other remote parts of Australia, and in the restoration of dryland rivers already affected by excessive water resource use.