13 February, 2010
Lakes-Letter to The Australian 13th February,2010
Could someone please explain to me (As one lakes region comes to life, another is saved from death-The Australian February 13th-14th) why returning the Lower Lakes (Alexandrina and Albert) to more like their natural state and allowing sea water to enter as it always did when upstream rainfall and flows were low, would be such a "natural disaster" equivalent to "death"?
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3 comments:
It will be death to the turtles, 'tortoises' actually, but they have been dying since 2008 due to tube worm infestations and salinity. It's very sad to witness it. I've saved one in my fish pond.
What you will also likely hear is the dreaded 'hypersalinity' word. For example if the barrages are opened then the lakes will turn 'hypersaline' because of low tidal flow through the Murray Mouth.
In this blog, http://lakesneedwater.blogspot.com/ that assumption is examined. And with a bit of research it is 'interesting' to see the limits placed on the scientific models on which the 'hypersalinity' claim is based. For example one limit was only opening the barrage gates every fortnight rather than relying on daily tidal exchange, etc. And assuming that the Murray Mouth would stay as restricted an opening as it is today.
Not a very open minded way to search for a solution is it?
Opening the barrages and allowing sea water into the Lower Lakes still means that freshwater coming down the river is important. It's the mix of fresh and sea water to create an estuary that will restore the Lower Lakes to a healthy ecosystem.
I wonder whether the fact that the Lower Lakes are kept artificially 'fresh water only', matters very much as a factor in the mindset of irrigators upstream?
Susan-thanks for your thoughtful comment. I fully accept that even with the Barrages open (or better still removed) fresh water from upstream will remain important. What seems to me to be missing in this whole debate is recognition of the enormous variability in upstream rainfall and run-off.
I wonder how many "downstreamers" realise that if it were not for the upstream dams (Dartmouth and Hume in particular)and the Snowy diversions, the Murray would have ceased to flow about three years ago? It is only the existence of these dams, the Snowy diversions and restrictions on irrigator extractions that has allowed an ongoing supply of fresh water to the lower Murray to be maintained in the face of the lowest run-off ever recorded.
This fact suggests to me that we need more, not less dams! But, they need to be deep and built to allow small flows to pass unimpeded.
I think that upstream irrigators greatly resent having to restrict their production, and in some cases sacrifice their financial survival, to supply water to an artificial fresh water storage at the end of the river where most of the water simply evaporates!
What is worse very few people, particularly the urban based "chattering classes" seem to understand the real situation-see the article in "The Australian" that provoked my so far unpublished letter.
Shadow Agriculture Minister, John Cobb, recently had an excellent "opinion piece" in "The Punch" which traced the history of Murray River "no flow" events and very gently highlighted the anomally (need a stronger word) of the Lower Lakes.
The most publically prominent scientist on the general subject of water (Adelaide based Mike Young) assiduously avoids the subject of the Lower Lakes fresh water storage and the massive evaporation therefrom. I guess it would be impolitic to press the issue in Adelaide!
More haste, less speed...................................................
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