Irrigation development on Cooper Creek, Central Australia - prospects for a regulated economy in a boom-and-bust ecology

Abstract

1. We take issue with a proposal to irrigate cotton crops from Cooper Creek, as the development would be in sharp contrast to the 'boom-and-bust' character of the local environment. In dryland rivers the flow regime is influenced by aseasonal climatic phenomena like the Southern Oscillation, so that patterns are highly variable and averages are virtually meaningless. Some irrigation developments on dryland rivers have been planned during periods that were unusually wet and, as a result, present levels of water use are not sustainable. 2. Long, dry periods are the norm in dryland rivers. The biota tolerate drought and respond to occasional floods that may have long-enduring effects (riparian trees, for example, may live for centuries). All are sensitive to the rates of rise and fall and the amplitude, duration and frequency of floods. Where the flood pulse is erratic, as in Cooper Creek, species with opportunistic traits are likely to dominate. Base flows and seasonal variations imposed by irrigation use present a very different physical environment for these species. The plan to tap the Cooper headwaters would amplify the impacts because this region is a refuge for flora and fauna. 3. In general, we contend that the Cooper Creek ecosystem could not accommodate a competitor for water that is vital for its own maintenance, and that the irrigation proposal could be rationalized only in the sophistry of short-term economics.