MURRAY-DARLING BASIN PLAN

The Hon. S.W. KEY (Ashford) (14:23): My question is directed to the Minister for the River Murray. What were the findings of the science review conducted by the Goyder Institute in relation to the guide to the proposed Murray-Darling Basin Plan?

The Hon. P. CAICA (Colton—Minister for Environment and Conservation, Minister for the River Murray, Minister for Water) (14:24): I thank the honourable—

Mr Williams interjecting:

The Hon. P. CAICA: It's not a comic, Mitch, so you probably wouldn't read it, so you'll learn something here today.

Members interjecting:

The SPEAKER: Order!

The Hon. P. CAICA: I do thank the honourable member for her very important question. The Goyder Institute is an excellent initiative of this government, and I acknowledge the Premier's foresight and commitment in ensuring the institute's establishment. I can inform members that the findings of a high-level science review into the Murray-Darling Basin Authority's guide to the proposed plan undertaken by the Goyder Institute, in partnership with its partner, the CSIRO, has recently been released. The review examined the implications of three environmental water recovery scenarios of 3,000 gigalitres, 3,500 gigalitres and 4,000 gigalitres, which had been proposed by the MDBA in their guide.

The science review findings demonstrate that there are environmental, social and economic benefits for South Australia under the guide's three proposed scenarios. Key environmental assets would benefit from increased flows under all three scenarios most of the time and South Australians may avoid the costs and impacts of extreme low water levels, such as those that were experienced over the past decade. The review found that water recovery scenarios of 3,500 and 4,000 gigalitres are most likely to enable South Australia to meet objectives for its two key environmental assets in the basin: the Riverland-Chowilla flood plain and the Coorong, Lower Lakes and Murray Mouth.

Below 3,500 gigalitres the achievement of those objectives becomes more problematic. Each of the three scenarios could support a permanent freshwater future for the Lower Lakes, improve the health of the Coorong and keep the Murray Mouth open more frequently than is currently the case. To achieve this outcome, however, environmental water would need to be delivered to this site in low flow years.

It is important to note that the method and timing of water delivery is critical. The science review highlights that there are existing physical and operational constraints which at times prevent the delivery of environmental water at the required frequency, timing and duration for these key environmental assets, with some of these constraints able to be overcome through changes to river operations and investment in infrastructure, works and measures. The report also found that water quality would be expected to improve under each scenario and the basin salinity target of 800EC at Morgan would be met. However, the MDBA salt load export target of two million tonnes per year on a 10-year rolling average would not be met under any of the three scenarios under discussion here.

The socioeconomic impacts for major water users in South Australia would be similar under all three guide scenarios. The review found that, in the worst case, if reductions were borne solely by irrigators, the economic costs could be between 4 and 6 per cent of average annual production value, or between $27.1 million and $43.9 million. Very importantly, the review also found that these impacts would be reduced through ongoing water purchase and investment in more efficient water infrastructure, both of which would potentially generate new economic activity in the region.

In this context it should also be noted that the commonwealth has already purchased significant amounts of water from South Australian irrigators, which is not taken into account in either the guide or the review. The review also indicated that the costs of mitigation measures associated with prolonged low flows and drought were estimated to be $790 million between 2002 and 2009. Under the guide scenarios, similar mitigation costs may be avoided in the future.

The review was based on information in the guide and the models that the MDBA developed to underpin it. Although the MDBA has since been reviewing its modelling and analysis, the Goyder science review has developed tools that will make it easier to assess the scenarios contained in the proposed basin plan when it is released. The Goyder review report will be provided to the MDBA to support the objective of having a clear scientific evidence base for the basin plan. It will also be used in formulating South Australia's response to the proposed basin plan following its release. I encourage all members to read the review, which I understand is available through the Goyder website.