Lake Eyre Basin Rivers 20 Limited). This scarcity of monitoring data makes understanding the hydrology of these complex rivers extremely difficult. And yet major decisions that depend on this understanding and being able to determine the impacts of flow regime changes on downstream landholders and the environment need to be made about the future of these rivers. Where – spatial variability Spatial variability is a major feature of Lake Eyre Basin river flows. Rainfall, run-off and river flow vary considerably across the Lake Eyre Basin (McMahon et al. 2008a McMahon et al. 2008b). Measurement of the most important input into any hydrological model, rainfall, is also particularly difficult, given the relatively few rain gauges in the Lake Eyre Basin (McMahon et al. 2008a). This contributes to the uncertainties of measuring the flow in Lake Eyre Basin rivers, an important area for research. Added to this, the complex flow paths and channel networks on the large, spectacular floodplains of the major Lake Eyre Basin rivers are confronting to monitor and model. The few gauging stations (Table 2.1) are naturally where flow convergence most efficiently measures flow volumes. But we have little information about what is happening to flow between these monitoring points, often hundreds of kilometres apart. In the magnificent Channel Country of Cooper Creek, between the junction of the Thomson and Barcoo Rivers and South Australia, flow can follow incredibly complex, anastomosing channels and floodplain paths, as it slowly moves downstream (Fig. 2.2). The Fig. 2.1. Cullymurra waterhole in South Australia, near Innamincka, is the site of one of only 13 river gauges in a river of ~1300 km (photo, R.T. Kingsford).