Murray-Darling Basin

The Hon. J.M.A. LENSINK (14:41): I seek leave to make a brief explanation before directing a question to the Minister for Water and the River Murray on the subject of the health of the Murray-Darling Basin system.

Leave granted.

The Hon. J.M.A. LENSINK: In October this year, the Murray-Darling Basin Authority provided $4 million to the South Australian government to ensure the Murray Mouth will stay open over the summer period. In May in this place, the minister advised that environmental flows and MDBA actions had prevented the need to dredge the Murray Mouth in 2013-14. I note that DEWNR's website states that 'water levels are continuing to be monitored and dredging may be reinstated—'

Members interjecting:

The PRESIDENT: Order! I hear voices from both sides of the chamber. The Hon. Ms Lensink, continue.

The Hon. J.M.A. LENSINK: DEWNR's website states that 'water levels are continuing to be monitored and dredging may be reinstated if there are significant changes in the channel profiles'. I understand the Murray Mouth has not required dredging since 2010. My questions are: does the minister continue to assert that the Murray-Darling Basin has been fixed and, if he does, how does he explain the need for dredging the Murray Mouth?

The Hon. I.K. HUNTER (Minister for Sustainability, Environment and Conservation, Minister for Water and the River Murray, Minister for Aboriginal Affairs and Reconciliation) (14:42): I thank the honourable member for her most important question. I know she has an ongoing interest in this area, and I am very pleased that she gives me an opportunity now to put on the record my concerns about the federal government's commitment to the Murray-Darling Basin Agreement and how they seem to be backsliding every time they go out into the community on the promises made by a previous government.

Before I get there, let me say that I think we can all agree that an open and functioning Murray Mouth is essential to maintain water quality and a healthy ecosystem, not just for that area but for the Coorong and, of course, further upstream. The mouth, of course, is highly dynamic, with its function being controlled by the balance of River Murray flows over the barrages and the ingress of seawater from the Southern Ocean. Reduced flows over the barrages have two main adverse impacts: they increase salinity levels in the Coorong and they reduce the openness of the mouth.

A continuous flow of at least two gigalitres a day, I am advised, is required to assist in maintaining the Murray Mouth being kept open most of the time. Flows of this magnitude reduce the rate that sand is deposited into the mouth through tidal activity, wave energy and storms. It is important to note that, without unregulated flow of large volumes of environmental water, South Australia does not receive enough Entitlement Flow during January, February and March each year to maintain the minimum flow of two gigalitres.

Periods of low River Murray flow have presented management challenges in the past, requiring continuous dredging operations during the eight-year period from 2002 to 2010. Since 2002, Murray Mouth conditions have been routinely monitored by the authority, the Department of Environment, Water and Natural Resources and, of course, SA Water to quantify the extent of mouth openness and changes in sand build-up. The physical condition and openness of the mouth have deteriorated rapidly since early 2014, I have been advised. This deterioration commenced at the end of a large unregulated flow event and of course was exacerbated by limited volumes of environmental water being available.

Full delivery of the Murray-Darling Basin Plan will result in increased volumes of environmental water being provided to South Australia for discharge over the barrages—that is full delivery. Modelling indicates that, under the 3,200 gigalitre water recovery scenario, the mouth should remain open 95 years out of 100. That is reliant on the federal government and other basin states delivering on the basin plan. Recent monitoring of the mouth's sand volume and bathometry—which is, of course, a measure of the depth of the mouth—confirms that the condition of the mouth is approaching that experienced in 2002 when it was decided to commence dredging.

A paper on the Murray Mouth management was considered at the basin officials committee meeting on 17 September 2014. The committee requested that the Department of Environment, Water and Natural Resources and the Murray-Darling Basin Authority progress planning and approvals to prepare for the possibility of dredging. I believe I am correct in saying that I asked the committee to do that at a previous minister's meeting somewhat earlier in the year.

At its meeting on 17 October 2014, the ministerial council approved a dredging program using funds to be drawn from existing Murray-Darling Basin Authority budgets. A Department of Environment, Water and Natural Resources-led multiagency steering committee, comprising representatives from the Murray-Darling Basin Authority, the Department of Environment, Water and Natural Resources and SA Water, continues to meet on a weekly basis, I am advised.

The DEWNR and other partners are working with the Murray-Darling Basin Authority to progress the necessary state and federal statutory approvals. They tell me that we should be in a position to be able to dredge as soon as, hopefully, December, if it's needed at that point in time.

The steering committee will be responsible for recommending the commencement of dredging to the respective agency and chief executives. The authority to approve the commencement of dredging lies with the chief executive of the Murray-Darling Basin Authority. Evaluation of recent monitoring confirms that, in the absence of a River Murray unregulated high-flow event—and, if it does occur, then we will be very happy not to have the need of dredging—it will be prudent to commence a dredging program, by the end of December of this year.

The important point to make is that this underlies the need for our state to be ever vigilant about the delivery of the Murray-Darling plan, and it's really important that the federal government not backslide on the commitment of providing the 450 gigalitres, or finding the SDL equivalents, to make sure we get the 3,200 gigalitres. It is not good enough to have representatives of the federal government touring through South Australia, putting their hands in the air and saying, 'I don't know where we are going to get the extra water from', when they are the ones who have said they will not buy water back for the system. That's the plan they took to the election.

They have stopped buying water. They say, 'We want to spend more money on engineering solutions', and that's great, but engineering solutions cost seven times as much as water buyback. The obvious solution is to continue buying back water for the ecological benefit of the system and for the Murray Mouth openness. The Liberal Party in Canberra are walking away from that at a million miles an hour.

The PRESIDENT: Supplementary, Ms Lensink.