17 September, 2010

Water and Irrigation

The recent flooding in Victoria and consistent rain in NSW has seen a great boost to storage levels in most of the major dams feeding the Murray Darling Basin. It is a timely reminder of the key feature of the Australian climate-massive rainfall variability. After some ten years of drought (on and off) and the lowest water run-off in our short recorded history, we are reminded just how fast things can turn around. It also reinforces how our philosophically green "water managers" have got it so wrong. I fear that we are going to see a graphic example of this when the long awaited Murray Darling Basin Plan is released on 8th. October.

How many times have we heard that our rivers have been "mismanaged and over allocated"? How many times have we heard that the problem is that "we are taking too much water out of our rivers"? When all the time the major problem has been simply lack of run-off creating rainfall.

Let's face it, water is dynamic and doesn't wait for you to use it. Rivers run to the sea, if they make it, and water in storage evaporates. Whilst we must keep a proper balance between environmental and socio-economic needs, in rugby parlance it really is a "use it or lose it" situation. Sure it would help if we could reduce evaporation from shallow storages and if we had more dams in the headwaters of our catchments. Consider that the Murray River would have stopped flowing altogether some four years ago, as it always did under very dry natural conditions, if it were not for the headwater dams (Dartmouth and Hume in particular), the Snowy diversions and restrictions on irrigation extractions. Yet we managed to keep water in the system and to our shame sent water down to the Lower Lakes, Australia's most inefficient water storage, to largely evaporate.

When are those upstream going to wake-up to the perpetual victim's attitude of most South Australians and insist that those wretched barrages at the Murray mouth are removed? They keep fresh water out of  The Coorong, stop the impact of tidal pulses keeping the Murray mouth open, and deprive the Murray of a natural fresh/salt water estuary.

When are we going to clearly explain to our well meaning city cousins (we failed with Penny Wong), the difference between a Water License/Entitlement and a Water Allocation? The former without the latter really is "phantom water". The  failure of the purchase of the Toorale Station water licenses to trigger any meaningful amount of additional water in 2010, is a wonderful case study demonstrating what little impact purchasing licenses, only triggered by big flows, actually has in a good flow year. Yet the negative socio-economic impact is very meaningful.

We need to explain that  we deal with the variability of river flows by way of seasonal allocations-no (or limited) water-no allocation. It's that simple. If we really are "over allocating" then we should reduce allocations, but why cancel licenses which in big flows may well contribute to flood mitigation. The residents of Shepparton would have liked to have seen more extractions (and/or more storage) upstream last week and a huge amount could have been stored whilst only being a very small percentage of the total flow!
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