Lake Eyre Basin Rivers 8 the large catchments, flowing south-west from Great Dividing Range. Its two main rivers, the Thomson and Barcoo Rivers (Fig. 1.1), are supplied by various creeks (e.g. Aramac Creek) and rivers (e.g. Alice River) before joining to form Cooper Creek, just upstream of the town of Windorah. The famous Channel Country is downstream of this confluence, where the Cooper can have a flood front which extends up to 80 km across, before it channelises and flows south-west into South Australia. This vast floodplain is like a sponge, soaking up water from the river and reducing the amount of water flowing downstream (Knighton and Nanson 1994). The river then flows past the small town of Innamincka, where it divides in large floods. Strzelecki Creek flows south to eventually reach the lakes north of the Flinders Ranges (Lake Blanche, Lake Gregory and Lake Callabonna, Fig. 1.1). However, most of the flow goes west where Cooper Creek bifurcates to supply the network of Coongie Lakes and a south arm, detailed in Chapter 2. The massive complex of lakes is within the Innamincka Regional Reserve (1.3 million ha), and includes the internationally recognised wetland of Coongie Lakes National Park, listed for its high environmental values (Puckridge et al. 2010). Once many of the lakes in this complex have filled, the northern branch flows south to join the southern branch of the Cooper (see Chapter 2), before flowing south-west again, where it floods a series of freshwater lakes and swamps (Kingsford et al. 1999). It then becomes confined to a channel before eventually reaching the eastern part of Kati Thanda-Lake Eyre. Flow patterns are highly variable (Kingsford et al. 2014): the Lower Cooper can flow every four years, and the Cooper reaches Kati Thanda-Lake Eyre about every 13 years (Kingsford et al. 1999). To the west of this large catchment, water flows down the Georgina and Diamantina Rivers (Fig. 1.1). Water flows south-west along the Diamantina River, past the town of Winton and then past Birdsville, before forming the massive floodplain of Goyders Lagoon. To the west, the Georgina River and its tributaries flow south to meet Eyre Creek and its vast floodplain (Fig. 1.5), which includes large freshwater lakes (e.g. Lake Machattie). It also receives water from the Mulligan River, on the eastern edge of the Simpson Desert, before flowing south to join the Diamantina River’s water in Goyders Lagoon. Once this floodplain is inundated, the river channel reforms as the Warburton River before flowing on to reach Kati Thanda-Lake Eyre. Four separate smaller rivers (e.g. Neales River) flow into the lake from the west (Fig. 1.1) their flows are more temporary than the rivers to the east, given their catchments lie in the most arid part of the continent (Kingsford et al. 2014). Booms and busts and ‘in between’ flows drive this ‘water environment’ Rivers of the Lake Eyre Basin are among the most variable in the world (Puckridge et al. 1998 McMahon et al. 2008). They oscillate between periods of extensive floods, driven primarily by summer seasonal rains of the Northern Australian Monsoon (Allan 1985), and extreme dry periods when there is little water in the landscape. Large tropical weather systems, particularly in La Niña years, can drive sequences of floods which may take many months to flow through the remarkably flat landscape all the way to Kati Thanda-Lake Eyre in South Australia (Kotwicki and Allan 1998 Puckridge et al. 2000 Costelloe et al. 2006). Kati Thanda-Lake Eyre receives water reasonably frequently, but rarely fills unless these