Jennifer Marohasy

a forum for the discussion of issues concerning the natural environment

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About the Murray River’s Estuary: Full Text of My Address to the Sydney Institute

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AT the very bottom of Australia’s Murray-Darling Basin is a vast coastal lagoon that was once connected to the Southern Ocean. The region was home for the Ngarrindjeri, who wore possum skin coats and loved to tell stories. One of their storiesii is about greed and the environment and also the consequences of telling lies.

Two men set off in their bark canoe for the Ngiakkung, a shallow, reed-filled corner of the lagoon their tribe favoured for fishing. That day thukeri, or bream, were so plentiful that the fish all but hopped into the canoe. Having acquired a substantial haul, one said, “Hey brother, we have plenty of thukeri. Let’s paddle to the shore before we sink.” But his friend, for whom plenty was never enough, wanted to keep on fishing. The fish piled up even higher in the canoe, which sank even lower.

Eventually, they paddled towards the shore, where a stranger stood. “Hey brothers, I’m hungry,” he called out, “Have you got any fish to share?”

The rapacious one replied, “No, we haven’t. Just enough to feed our families.”

As the stranger turned to walk away, the men started laughing behind their hands. The stranger heard them and said, “You have plenty of fish, but because you are greedy and don’t want to share, you will never enjoy the thukeri again.” When the men reached the bank, they found the fish they had caught were thin and full of sharp bones.

They told their families what had happened. The old people said that the stranger was the Great Spirit Ngurunderi. From then on, for all time, the Ngarrindjeri people would be punished. Today, whenever Ngarrindjeri catch a bony bream, they are reminded of long ago, when Ngurunderi taught them a lesson.

During the recent drought, the waters of Ngiakkung, a place now called Loveday Bay, dried up. No one could ever remember the lagoon, now called Lake Alexandrina, drying up before.

[Read more…] about About the Murray River’s Estuary: Full Text of My Address to the Sydney Institute

Dugong Slaughter: Finally Some Reporting of the Issue

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Dugongs are large marine mammals that swim about northern Australian waters. Indigenous Australians are allowed to hunt dugongs even though their numbers are probably in serious decline.

There are two criteria that should be applied to the harvest of an animal species: 1. Are the numbers taken sustainable, and 2. Is the method of killing humane?

But these criteria do not apply to the slaughter of native animals under native title legislation in Queensland.

I’ve written on the issue before, but not much since 2008. [1]

There has been a campaign wagged out of Cairns to get this issue on the national agenda and finally tonight there was some reporting of the inhumane slaughter of dugongs in northern Australian waters by the ABC TV 7.30 Report.

http://www.abc.net.au/7.30/content/2012/s3448943.htm

Well done to Sarah Dingle and Lesley Robinson for following up on a story documented by Ruphert Imhoff.

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[1] https://jennifermarohasy.com.dev.internet-thinking.com.au/2008/01/ignoring-the-slaughter-of-dugongs-in-northern-australia/

The Moon and Rainfall in Eastern Australia

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Dear Jennifer,

My paper ‘Lunar Tides and the Long-Term Variation of the Peak Latitude Anomaly of the Summer Sub-Tropical High Pressure Ridge over Eastern Australia’ has been published at:

http://www.benthamscience.com/open/toascj/articles/V006/49TOASCJ.pdf

It can be down loaded for free!

The main take-home conclusions from this paper are that:

1. The most important influence upon the climate of Northern NSW and Southern Queensland after the La Nina/El Nino phenomenon is the Peak Latitude Anomaly for the Summer Sub-Tropical High Pressure Ridge over Eastern Australia (L(SA)).

2. The interannual variability of L(SA) is major mechanism influencing inter-annual rainfall variability in Eastern Australia. It has also been shown to be connected to the inter-annular variability of the annual mean maximum temperatures, zonal westerly winds, meridional winds and mean air temperature.

3. The long-term (i.e for periods of 2 to 20 years) variations of L(SA) are dominated by (significant) periodic signals at 9.4 (+0.4/-0.3) and 3.78 (+/- 0.06) years.

4. L(SA) systematically moves away from the Equator as the angle between the Earth-Sun axis and the line-of-nodes of the Lunar orbit (at the time of perihelion) decreases. The magnitude of the movement of the mean summer peak latitude anomaly can amount to 1 degree of latitude over the 9.3 year semi-draconic spring tidal cycle.

5. L(SA) systematically moves towards the Equator as the number of days (to the nearest full day) that New/Full is from Perihelion decreases. The magnitude of the movement of the mean summer peak latitude anomaly can amount to 0.7 degree of latitude over the 3.8 year peak spring tidal cycle.

6. The 9.4 year signal in L(SA) is in-phase with the draconic spring tidal cycle, while the phase of the 3.8 year signal in L(SA) is retarded by one year compared to the 3.8 year peak spring tidal cycle.

7. This paper supports the conclusion that long-term changes in the lunar tides, in combination with the more dominant solar-driven seasonal cycles, play an important role in determining the observed inter-annual to decadal variations of L(SA).

8. The IPCC does not take into account the important effects upon climate of long-term
lunar atmospheric tides.

Cheers,
Ian Wison
Toowoomba, Queensland, Australia

SA Minister Caica Needs to Read My Report

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FRESH water allocated to the Lower Lakes in the Murray-Darling Basin Plan is a “waste” and only serves to maintain an “artificial” environment, a new report says…

Reports Lauren Novak and Ken McGregor from the Adelaide Advertiser got that much right.

Their article is available online here http://www.adelaidenow.com.au/news/south-australia/water-must-mix-in-the-lower-lakes-says-new-murray-darling-report/story-e6frea83-1226281052851

Comment in their article by State River Murray Minister Paul Caica that the Lower Lakes were not estuarine before construction of the sea dykes is nonsense. Lake Alexandrina is the central basin of a typical southern Australian barrier estuary.

To understand something of the long and short history of the Murray River’s Estuary read my short report

‘Plugging the Murray River’s Mouth: The Interrupted Evolution of a Barrier Estuary’

at https://jennifermarohasy.com.dev.internet-thinking.com.au/wp-content/uploads/2012/02/Plugging-the-Murray-Rivers-Mouth-120212.pdf

It’s a Barrier Estuary: Duh!

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IN South Australia the Coorong fishermen say that before irrigation, before the weirs, locks, levees and barrages (sea dykes), the Murray River would flog down from September until maybe Christmas, filling the lagoon, then out the mouth. By Christmas, flow had usually slowed and water levels dropped right down. Then when the South Westerly wind picked up the sea would pour in through the mouth and work its way across the lake.

So Lake Alexandrina was fresh in spring and summer, but salty by autumn.

What the old fishermen describe is an estuary: a transition zone. The Murray River had a barrier estuary with a central lagoon, Lake Alexandrina, and a sand barrier, the Younghusband Peninsula. A single, narrow and shallow inlet that often closes over is also a characteristic of barrier estuaries.

There are many barrier estuaries along the southern Australian coastline including Lake Illawarra just south of Wollongong. According to the Lake Illawarra Authority’s management guide, freshwater flows into the lake from the escarpment and salty water from the ocean tides and therefore it is an estuary. There are 70, of these Intermittently Closed and Open Lakes and Lagoons, known by the acronym ICOLL, from Sydney to the Victorian border. A significant issue is management of the risk of flooding when their ‘mouths’ close over. NSW State government policy doesn’t support the artificial opening of ICOLLs.

The South Australian government insists the Murray mouth, which is the inlet to Lake Alexandrina, be kept open. In fact since European settlement there have been many schemes devised to change the Murray’s mouth to make it deeper and wider, including through blasting and dredging and more recently through water reform.

There is this invented narrative that the Murray’s mouth closes over because greedy upstream irrigators have stolen all the water, but the reality is Barrier Estuary’s close over naturally. The long-term solution is to remove the Murray Mouth barrages – the sea dykes – that have interrupted the evolution of this system and so let it develop to a fully mature state. Mature barrier estuaries tend to be fully tidal.

The sea dykes dammed the estuary making it totally dependent on river flows. Stopped the tide. Limiting natural scouring of the sea mouth in spring by the river flow and in autumn by the Southern Ocean. Not surprisingly the hydrology and geomorphology of the Murray’s mouth has changed with sand that used to shoal behind the mouth consolidating into Bird Island that continues to grow and may one day permanently plug the Murray’s mouth.

Indeed Federal Water Minister Tony Burke can buy back all the water from all the irrigators across the entire Murray Darling, but this will have very little real impact on the Murray’s mouth.

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To learn more about barrier estuaries and why Lake Alexandrina was once part of a wave-dominated barrier estuary and which sea dyke should be removed first read my latest technical paper ‘Plugging the Murray River’s Mouth: The Interrupted Evolution of a Barrier Estuary’
at https://jennifermarohasy.com.dev.internet-thinking.com.au/publications/

More Flooding

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Large areas of Queensland and New South Wales are flooding again.

In New South Wales:

Flood Warning – Clarence River,
Flood Warning – Bellinger River,
Flood Warning – Hastings River,
Flood Warning – Manning River,
Flood Warning – Orara River,
Flood Warning – MacIntyre River,
Flood Warning – Gwydir River,
Flood Warning – Peel-Namoi Rivers,
Flood Warning – Castlereagh River,
Flood Warning – Culgoa-Bokhara-Narran Rivers,
Flood Warning – Warrego River,
Flood Warning – Paroo River,
Flood Warning – Barwon-Darling Rivers,
Flood Warning – Paterson-Williams Rivers,
Flood Warning – Nambucca River.

In Queensland:

Flood Warning – Burdekin River,
Flood Warning – Fitzroy River,
Flood Warning – Condamine-Balonne Rivers,
Flood Warning – Macintyre/Weir,
Flood Warning – Moonie River,
Flood Warning – Nebine/Wallam/Mungallala,
Flood Warning – Warrego River,
Flood Warning – Paroo River,
Flood Warning – Bulloo River,
Flood Warning – Thomson/Barcoo/Cooper Ck,
Flood Warning – Western Queensland Rivers,
Flood Warning – Gulf Rivers.

http://www.bom.gov.au