The bleak outlook for the Murray-Darling Basin has just got substantially worse with reports that inflows may have been overestimated by as much as 40 per cent, as a result of double counting of groundwater. Of course, as Malcolm Turnbull says in the article, the general problem is well-known to those working in the area. The Risk and Sustainable Management Group*, which I lead at UQ, has been working on it for some time, and so have lots of others. But, as we know all too well from our modelling efforts, there’s a huge gap between a qualitative understanding of the issues, and an adequate quantitative representation of flows of water and salt, not to mention the nutrients that contribute to things like blue-green algae blooms. Everyone is doing the best they can, but it will take a long time to get coherent data sets together, and time is something we don’t have.
In the meantime, policy is at a standstill because the National Party refuses to countenance voluntarily repurchase of water rights, let alone a scaling back of allocations that are, in retrospect, obviously unsustainable. Unless Turnbull can really start banging some heads together on this one, his first ministerial stint is going to end up a disastrous failure.
* I’m reposting this at the RSMG blog, which has lots of useful discussion of water and other environmental issues.
Update 18/5 It turns out this estimate is from Bill Heffernan (I had somehow inferred that the National Water Commission had produced it) and it’s an upper bound, based on the total contribution of groundwater. Turnbull has a letter in today’s Fin suggesting that the real value is 3 per cent, though I don’t think this includes capture of surface flows through farm dams, laser levelling and so on. Even 3 per cent of flows is a big deal – much more than the amount that has so far been repurchased or regained through efficiency savings.