17 August, 2010

Murray Darling Basin

On Sunday 15th August I sent the following letter to the Sydney Morning Herald.
"Senator Wong's response ( Phantom Water SMH 14th August) to Debra Jopson's expose on phantom water (SMH 12th August) clearly demonstrates how the Senator and her extreme green advisers just don't "get it". The "lack of water flowing down the rivers of the Murray Darling Basin" is not caused by "decades of mis-management and over-allocation". It is caused by the lack of inflows to which the Senator refers. Let me try to explain.

Australia's rivers are highly variable and water is dynamic, it either runs away to the sea or it evaporates. We deal with the variability by building storages and having seasonal allocations for irrigation. When there is no or very limited water, there are no allocations. Having some water in the headwater storages, with minimal allocations for irrigation, allowed the Murray River to be kept flowing through this drought of record low rainfall and run-off into the river and dams.

Buying back an irrigation license/entitlement when there is no allocation generates no water. It will "generate" extra water (leave it in the river) when there is a good flow or flood and there would have been an allocation, but that is not when our rivers most need it and that will limit agricultural production for negligible environmental benefit.

By way of example, the first major water buy-back by this Government was the purchase of Toorale Station, Bourke in 2008 for $23.75m. There has been additional water in the Darling River as a consequence of this purchase during the big flows earlier this year. This additional water amounted to less than 1% of the flow past Bourke! Of the flow past Bourke that reached either the Menindee Lakes Storage or the Lower Lakes Storage at the mouth of the Murray, at least 50% will evaporate.

Engineering changes to reduce evaporation of fresh water in these storages could make a meaningful impact. All we have seen so far is political action pandering to misconceptions which will do little for the environment but have a long term negative impact on our ability to produce agricultural products for a hungry world."
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