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House of Assembly - Fifty-Second Parliament, Second Session (52-2)
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PUBLIC WORKS COMMITTEE: PATAWALONGA LAKE SYSTEM SEDIMENT MANAGEMENT PROJECT

Mr SIBBONS (Mitchell) (11:35): I move:

That the 479th report of the committee, entitled Patawalonga Lake System Sediment Management Project, be noted.

On receipt of the Patawalonga Lake System Sediment Management Project submission, the committee was of the opinion that the extent of works contained therein did not constitute the whole of the public work, as defined in the Parliamentary Committees Act 1991, contemplated by the full scope of the project. The submission allocates funding to developing a longer-term solution, which will be developed and constructed, subject to funding.

The committee resolved to address this initial phase of immediate sediment removal through an interim report. This means that the current report does not constitute a final report, enabling the construction of any works over and above the mere removal of sediment countenanced in the attached submission provided to the committee. The committee resolved that the various long-term options mooted in the current submission, or variants thereof, would constitute a public work. Therefore, before DEWNR moves to begin implementing any such solution, it must submit a proposal to the committee for consideration and a final report.

The committee has received the proposal to manage the sediment accumulation at the Patawalonga Lake System. The sediment management project (SMP) will establish contract services and any necessary infrastructure for:

initial removal of accumulated sediment from the basin;

ongoing (e.g. yearly) removal of accumulated sediment at the basin, subject to funding;

ongoing monitoring of the sediment (quantity and character) within the basin; and

conduct trials to achieve continuous improvements and innovation (trials may include: de-watering, draining, composting, etc.) to reduce sediment removal costs in the long term.

Sediment accumulation has been a significant issue at the Patawalonga Lake System since it was commissioned in 2001. Accumulated sediment poses a significant threat to the operation of the Patawalonga Lake System and the lake's water quality. The project is estimated to cost approximately $5.7 million, excluding GST. The project is expected to be complete in late June 2014. In working toward a longer-term solution and preparing a submission for the Public Works Committee to consider and report on such a proposal, DEWNR is not prevented from going to tender and planning, but it is prevented from starting construction of any such project, as provided in section 16A(2) of the act.

Even though this report has been designated an interim report, the committee will still require DEWNR to provide quarterly reports on this development and progress of the sediment removal project. This is consistent with committee practice. Given this, and pursuant to section 12C of the Parliamentary Committees Act 1991, the Public Works Committee reports to parliament that it recommends the proposed public works.

Dr McFETRIDGE (Morphett) (11:39): I rise to support the report of the Public Works Committee on the Patawalonga Lake System Sediment Management Project. As members will know, the Patawalonga Lake is central to my electorate of Morphett and is at the bottom end of the Brownhill Creek, Keswick Creek, Airport Drain and Sturt Creek drainage systems, and we receive about 8,000 tonnes of rubbish from our upstream neighbours every year. Managing the sediment and that floating rubbish has been an ongoing problem.

The Patawalonga was the second most polluted waterway in Australia when the then federal government introduced some funding to improve cities. I think it was called Better Cities funding and I think $13 million—I might stand corrected on that—was spent back in the 1990s to clean up the Pat and to remove the sediment. There were hundreds, if not thousands, of tonnes of sediment taken out of the Patawalonga Lake and stored on land on the western side of the airport.

The changes that have been brought about by the clean-up of the lake itself were just amazing to the point where I remember, in the 2002 election campaign, the then minister Brindal and I went for a swim in the Pat and we showed that the Pat had actually been cleaned up. However, the issues with the sediment and the rubbish coming down from upstream have still been ongoing.

There is a set of gates there now with the construction of the Barcoo Outlet. We have the old lock gates still down at Holdfast Shores there and there are other issues with them, which I will speak about in a moment, but the northern end, the Barcoo Outlet, which was constructed with a lot of controversy, has proven to be a godsend for the people of Glenelg.

We know that on 27 June 2003, when the southern lock gates down at Holdfast Shores did not operate properly, we had a high tide and heavy rainfall and we had serious flooding going out through hundreds of homes in Glenelg North. There were lives ruined and homes ruined; there were marriages ruined and I understand there was one suicide that resulted out of that whole event. It was a tragedy, so we need to make sure that we not only keep the Pat clean but we manage the system there. Managing the sediment is part of that whole process.

Where the creeks come through under Tapleys Hill Road, there is a boom that helps catch all the floating rubbish, and there are thousands of tonnes of that, but underneath that the sediment has been building up behind the second basin where there is a weir. The boom forms the first basin; there is a second basin with a concrete weir and then water and sediment has been diverted off into what is called the diversion basin, which then pushes water out through the Barcoo Outlet under the sand dunes out to sea at the appropriate times.

The sediment then goes over that weir. It does not go into the diversion basin, it accumulates at the northern butterfly gates, which are gates that pivot on a centre axis. They open up and form part of the Barcoo recirculation system. At high tide the lock gates down at Holdfast Shores are opened and water comes in at that end. At low tide, at the northern end, the butterfly gates open and water then goes out through the Barcoo. So, about every 48 hours, the water is exchanged in there and it keeps that water in a fantastic condition.

We have not had too many events there like we used to have. In the old days we had all sorts of waterskiing events and the Milk Carton Regatta did make one appearance back there. I am trying to get the Birdman Rally to come back—it was on the Glenelg jetty, but I hope it may one day be on the Patawalonga. There are hundreds of boats brought in there; millions and millions of dollars' worth of boats are being moored in the Patawalonga now and maintaining that system is going to be an ongoing problem.

I am glad to see that this report does acknowledge that this is just the first step in a long-term solution for a long-term problem because that sediment is building up. As I said, there are thousands and thousands of tonnes—between 4,000 and 8,000 tonnes every year—coming down from our upstream neighbours. I understand there are some plans in train to help control the water that comes down but controlling that sediment is something we need to be aware of as well.

The digging up of sediment, the dewatering of the sediment and then the disposal of the sediment are obviously big issues and expensive issues. It costs a lot of money to do that. The cost of this initial project is $5.7 million. I understand the ongoing annual recurrent costs are anything between $800,000 and $1.2 million. The bottom line, though, is that, with three million visitors a year coming down to Glenelg, it is a declared tourist area and we need to make sure that the Patawalonga basin and the Patawalonga lock gates are working well and the lake is looking pristine. An ongoing sediment management plan is a very good thing to see for the people of Glenelg North, who are subject to flooding.

I should also say that should things go wrong down there, if it is not managed well, it is not just the houses and businesses around there but we have also got the Adelaide International Airport. If you look back at historical maps that whole area was swamp. Sturt Creek used to empty out onto the swamp behind the sand dunes and would filter its way north and enter down by Port Adelaide. The River Torrens never went out to the sea. It is now a perched river, the Torrens River, and it used to go out north.

What we have got now is the outlet through the Pat, we have the perched river, the Torrens, but we have also got huge inflows coming down because of urban infill, because of the run-off from roads and concrete footpaths and other infrastructure and infill. We have got thousands and thousands of litres of water running off into the creeks and coming down towards the Pat and towards Glenelg. Managing that whole system is something that the state government needs to be aware of.

I know that there have been many plans over many years to make sure that the disasters are averted. I am very pleased to see that this is just another part of making sure that the bottom end of the system, where all the rubbish is ending up at the moment, is going to be managed in a better and long-term fashion. I congratulate the committee on the report. I look forward to further updates on the management plans. I have been lucky enough to have briefings down there from various government officials that have been involved, and I have attended public meetings down there.

I must say that I am still very concerned about the short-term solution we have got for the lock gates at Holdfast Shores. These are the old gates that are lifted up by counterweight, concrete weights. It is about a $3½ million project to upgrade and repair them. The total cost of replacing them is about $10 million, but when you consider the infrastructure that is at risk if things go wrong down there I think we really do need to look at our priorities.

I urge the government most strongly to reconsider the spend down there on the southern lock gates at Holdfast Shores, because if they do not work, if they malfunction like they did in 2003, well, then, not only is it the homes and businesses that are at risk, but it is also going to be the Adelaide Airport and it could be worse than that—it could be further up. No lives have been lost directly, as I say, but lives, families and businesses were severely impacted. This is a start, this sediment management plan, and I look forward to seeing it progress.

The Hon. R.B. SUCH (Fisher) (11:47): I will just make a couple of points. I commend this project, but I point out that the riverine environments in South Australia, particularly in the Mount Lofty Ranges area and adjacent areas, have suffered significantly since European settlement. Aboriginal people were able to look after the natural environment for 50,000 years. We have done a lot of damage in a couple of hundred years. What needs to happen now—and I am urging the government, and I would hope the opposition would support it—is that we have programs to revitalise and restore some of the riverine environments not just immediately in and around Adelaide but further out as well. Most of them are degraded, full of weeds and exotic plants, and they need to be brought back to something like what they were before European settlement. That will not happen in any pure sense but it is an important issue.

A report was released a few months ago, which I think was funded by the NRM and supported by, I believe, the minister for the environment, highlighting some of these creeks and rivers that are sadly in a state of neglect and, worse, have been severely damaged by inappropriate activity. I know it is peripheral in a sense to this issue, but one of the reasons we have problems at the Patawalonga is reflective of a wider issue about not only the Sturt River but also all the other rivers that are in or near the Mount Lofty Ranges.

I commend this project, but I would urge the government and also the opposition to get on board in terms of supporting the revitalisation of our riverine environments. I notice that in the recent election I think Simon Birmingham, the senator, announced money to be spent on the Torrens River, and I applaud that, but we need to go beyond that. It is not simply about nitrogen overload in the Torrens; it is a much broader issue of restoring habitats, revegetating and trying to restore, as I said before, these creeks and riverine environments back to something approximating what they used to be before European settlement.

Mr VENNING (Schubert) (11:50): This is an issue that I have more than a casual interest in. I was chair of the ERD Committee when we took evidence on issues down there. This was before the boat harbour was built and it was also before we built the new high-rise facility down there. What is it called?

The Hon. R.B. Such: Holdfast Shores.

Mr VENNING: Holdfast Shores. Without being too political about this, I just think we ought to be revisiting some of that evidence and have a look at what was said because it really has not stacked up too well, in my book. At the same time, I was also involved with the preliminary planning and the assessment of the Barcoo Outlet project, which I do believe is a success. It is working, I understand. Could I again pay tribute to the government project officer who, of course, is still around—Rod Hook—who gave evidence on that.

When he was under fire, I certainly supported and stood by his experience and his advice, which has turned out to be true, because I think the Barcoo is quite clever. Rather than having the flushing out through the front of the Patawalonga, to flush it out on the tides, as happens, is a clever thing to do. In time, I would like to revisit that to see how effective it actually is. When minister Brindal was in charge, we hoped to clean it up to the point of being able to swim back in the Patawalonga. That has not happened. Even though we did go swimming one day, it probably was not legal.

Mrs Geraghty: I remember that.

Mr VENNING: The member for Torrens says she can remember that. Talk about painting bridges! That was much more controversial. Apparently, the amount of silt in the Patawalonga is a concern. Can I say it is a wonderful part of our city down there and we need to protect it. Of course, it is always the subject of a fair bit of controversy, particularly when they forgot to open the gates and the water flooded over the edge and caused a few problems. I think that was when we were in government—these things can happen.

When we interfere with nature, like we have done with our rivers and streams, we have to be oh so careful. I think reports like this one are certainly timely and we should be doing them regularly. Can I just say that I am very concerned about what has been happening down there with the boat harbour. Having a house very near there, it really narks me to see that dredge working 24 hours a day, seven days a week. I think that is appalling. We have locked future generations into that cost.

I think there is a way around this. We are now seeing the sand pumping pipeline there. I do not know whether or not it is working yet, but I see they have put it in. There are all these costs because we are meddling with nature, and I just question that. I do not know why we are seeing this huge sand and seaweed build-up at the entrance to the boat harbour. I do not understand how that can happen because we have interfered with the tidal movements off the beach. In retirement, I will certainly take more than a casual interest in this because I intend to be living down there. I will be reporting to the house pretty regularly about progress or the lack of it.

Motion carried.

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