NATURAL RESOURCES COMMITTEE: WATER RESOURCE MANAGEMENT IN THE MURRAY-DARLING BASIN

The Hon. R.P. WORTLEY (16:00): I move:

That the report of the committee, on Water Resources Management in the Murray-Darling Basin Volume 2 'The Two Rivers', be noted.

This is the second major report of the Natural Resources Committee relating to this inquiry. The first report follows on from Volume 1 'The Fellowship of the River' and a separate issues paper regarding critical water allocations. The title of this report is 'The Two Rivers', which is a reference to the vastly different personalities of the Darling and Murray Rivers. As members would be aware, the Darling is an ephemeral river, pulsing with great surges after irregular torrential downpours while in between times it remains a sleepy, ambling stream often ceasing to flow altogether.

The Darling is separated from the Murray by vast expanses of arid inland Australia, extensive floodplains and the Menindee Lakes near Broken Hill which, when full, evaporate 750 gigalitres of water per annum. The Murray on the other hand has, up until recently, been fed by regular winter rains falling in the South-East of the continent. It has generally been dependable and, over the decades, has been a source of considerable prosperity. The Darling is much less important to South Australia than the Murray, with the Darling under natural conditions contributing an average of 16 per cent to the total flows of the Murray.

The argument that Cubbie Station or any other large northern water licence holder should be purchased in order to return the water to the system to benefit South Australia's Coorong and Lower Lakes is unfortunately misguided and flawed. Such a purchase would unfortunately assist the South Australian reaches of the basin very little, if at all.

A combination of transmission losses, evaporation and allowable extractions would return just a tiny fraction of any water bought for South Australia. Such an expenditure would be very difficult to justify. As part of its April 2009 South Australian Riverland fact-finding tour, the committee inspected the Yatco Wetland Water Savings project overseen by the Yatco Wetland Landcare group, comprising local irrigators, with support from state government departments, the South Australian Murray-Darling Basin NRM board and local businesses.

Since construction of Lock 3 in 1925, Yatco Lagoon had been permanently inundated, creating a shallow and highly effective evaporation pan over its 346 hectares. In November 2007, in an effort to reduce evaporation and save River Murray water, a permanent rock wall and regulator were constructed to isolate the lagoon from the main river channel, drying it out completely.

In March 2009, the regulator was opened allowing three gigalitres of water through to slowly refill the wetland. As a result of the extended drying period, approximately three gigalitres of water was prevented from evaporating. A new management plan has now been developed with wetting and drying cycles more closely mimicking a natural system.

This new management regime is expected to improve the ecology and water quality which were suffering under permanent inundation and reduced evaporation from this wetland by approximately two gigalitres every three years. The committee was impressed with the apparently successful efforts to reduce evaporation from Yatco Lagoon while also improving its ecology by establishing a pattern of wetting and drying. Members would like to see consideration given to a similar project for nearby Wachtels Lagoon in order to achieve similar outcomes.

I thank all those who gave their time to assist the committee with this inquiry. I also commend the members of the committee: Presiding Member, Mr John Rau MP; the Hon. Graham Gunn MP; the Hon. Stephanie Key MP; the Hon. Caroline Schaefer MLC; the Hon. Lea Stevens MP; and the Hon. David Winderlich MLC, for their contribution and support. They have worked cooperatively throughout this inquiry. Finally, I would like to thank the staff of the committee for their assistance. I commend this report to the council.

Debate adjourned on motion of Hon. I.K. Hunter.