Bad news on the Murray
Grim if unsurprising news from this Leaked report on the state of the Murray-Darling river system. The failure of the autumn rains (again) has wiped out the modest benefits from the (already fading) La Nina event. The problem has been generated by a long history of bad policy, but, at this point, even the best water policy in the world won’t help if it doesn’t rain.
The implications for places like the Coorong are dire. It seems likely, in view of problems like the buildup of acid sulphate soils, that the barrages separating the Lakes Alexandrina and Albert from the sea will have to be removed (this is being staved off by emergency measures for the moment). But the barrages were constructed as an early response to the expansion of irrigation upstream, which reduced flows and, as a result of sea water inflow, threatened to turn predominantly freshwater lakes into salt water (characteristically of such interventions, the barrages overcorrected, eliminating the occasional salt water phases, and changing the ecological balance in the lakes). So, the only sustainable response is to increase flows in the whole system which will require substantial reductions in extractive uses.
But, if the repeated failures of the autumn rains, and the higher frequency of drought represent a permanent climate change, it seems likely we will have to accept both substantial ecological damage and reduced agricultural output. My research group at UQ has been working on this for the Garnaut Review and we should have a report out fairly soon – some of the scenarios are indeed grim.