Lake Eyre Basin Rivers 26 decadal records before temporal variability can be quantified. We need to have knowledge of flow variability for infrastructure development adjacent to the river or its tributaries. This information can be generated by developing rainfall run-off models, but without observed flow data to calibrate or evaluate the model, there will be a large degree of uncertainty in the results. The consequences of inaccurate estimation of flood frequencies can affect estimates of impacts on ecosystems, ecosystem services and infrastructure (e.g. roads). The high interannual flow variability of Lake Eyre Basin rivers has implications for extraction of water from the rivers. Variability in magnitude and timing means that water extraction would be relatively unreliable for agricultural or mining requirements using flow- based thresholds. For example, current extraction rules for inactive irrigation licences in the (b) (a) 0.0 1.0 2.0 3.0 4.0 5.0 6.0 0 10 000 20 000 30 000 40 000 50 000 60 000 70 000 80 000 Fig. 2.8. Algebuckina Waterhole on the Neales River showing (a) observed water level with increased frequency of flows, 2009–2011 and (b) modelled daily flow (Costelloe et al. 2005), illustrating that the period of observed data (post-1999) had more frequent flow events than the preceding 20 year period. 01 -M ar -0 0 01 -M ar -0 1 01 -M ar -0 2 01 -M ar -0 3 29 -F eb -0 4 28 -F eb -0 5 28 -F eb -0 6 28 -F eb -0 7 28 -F eb -0 8 27 -F eb -0 9 27 -F eb -1 0 27 -F eb -1 1 27 -F eb -1 2 26 -F eb -1 3 26 -F eb -1 4 Water l (m) 01-Jan-79 01-Jan-81 01-Jan-83 01-Jan-85 01-Jan-87 01-Jan-89 01-Jan-91 01-Jan-93 01-Jan-95 01-Jan-97 01-Jan-99 01-Jan-01 01-Jan-03 Flow (ML/day)