There’s a clear solution to the management problems of the Murray-Darling, at least in the view of many South Australians: a full Commonwealth takeover of the Basin, one that would end the reliance on State cooperation and establish the Commonwealth as the sole guardian of the river system.

One of Nick Xenophon’s first acts on arrival in the Senate was a private member’s bill to give the Commonwealth authority to take over management of the Basin. Greens Senator Sarah Hanson-Young says “the only way I see the basin having a future is if it’s managed fairly, and if it’s not managed by the States.”

Both say the Inter-Governmental Agreement signed last July is ineffective.

Liberal Senator Simon Birmingham, another staunch advocate on water reform, compares the current arrangements to being half-pregnant, and compromised by the residual powers of the States and the fact that the States can withdraw referrals of powers or stop cooperating at any time. He wants to see clear Commonwealth power over the MDB. Christopher Pyne is another South Australian Liberal who has urged for years a full Commonwealth takeover.

The Coalition view outside South Australia is a little less forthright. Shadow Environment spokesman Greg Hunt says there are two key issues to be resolved on the MDB.

“There needs to be a genuine set of referred powers from the States to the Commonwealth that would allow for legitimate planning across the Basin, and the replumbing of regional Australia, which has been the subject of an unforgivable delay by Penny Wong, needs to be expedited.”

For Hunt, the issue is achieving Commonwealth control, not the mechanism for how it is achieved.

Hunt’s view is similar to that of the Senate committee (chaired by National Fiona Nash) which recommended  that the “Commonwealth work towards a full and unconditional referral of powers relevant to the management of the MDB and, in the absence of such full referral, consider pursuing other options to provide for complete federal management.”

Elsewhere there is less conviction that any radical change is necessary. The National Farmers’ Federation told the Senate Inquiry it wants to wait for the first five-year review of the IGA in 2014 before reconsidering governance arrangements. NSW Irrigators’ Council CEO Andrew Gregson, while critical of the Commonwealth’s intervention in the water market — particularly the slow rollout of irrigation infrastructure funding — believes the new process can be made to work.

“There’s an Inter-Governmental Agreement. If people have a concern about issues like water shares, it can be thrashed out and the IGA changed. What would a Federal takeover specifically mean? The water market needs to be stable, and not subject to the arbitrary control of a single minister. The reason the Basin is in crisis is because of the drought.”

There are other concerns about a Commonwealth takeover. It wouldn’t address the need for, and might even undermine, community involvement in water purchasing and irrigation infrastructure decisions. Evidence and case studies suggest the greater community involvement in purchasing and investment decision-making along the basin, the more effective it will be. There is also a concern that a Commonwealth takeover would simply transfer control from one group of politicians to another.

“Single control of the Basin needs to be driven by the Federal Government but be independent of the Federal Government,” Hanson-Young maintains.

Gregson’s point about what the specific purpose of the Commonwealth takeover would be is an important one. Apart from the lack of rain, the critical problems in the MDB currently are the absence of a single, fair water trading market, especially in Victoria, the continuation of State water plans, the Queensland Government’s unwillingness to restrict water diversion, the lack of control of unregulated water interception and mining in the north of the Basin, and the lack of investment in irrigation infrastructure.

There are other potentially significant issues, such as the continuing role of the States in Basin decision-making, but they remain weaknesses at this point rather than real problems.

Some of these problems will not be affected by who is in charge. The slow pace of investment is now being remedied as Commonwealth funding starts rolling out to the States, and there is no guarantee a Commonwealth authority will be more diligent at preventing unauthorised water interception or exempted land-clearing by mining companies.

Independent MP Tony Windsor is very worried about the impact of longwall coal mining on the Liverpool Plains in northern NSW, which may have significant effects both on groundwater and aquifers in the MDB. The Commonwealth is probably even less likely than the NSW Government to intervene on that issue.

But the apparent inability of the States to agree on a single water trading market — South Australia is expected to commence its High Court case against Victoria in the next fortnight, while NSW has imposed an embargo on further water trading — appears only remediable via Commonwealth takeover. This would also address the bewildering inconsistencies across the four MDB states in water trading, where there aren’t even common terms or consistency in relation to links between land and water rights.

A Federal takeover could be done via existing constitutional powers, University of Adelaide professor John Williams has argued — specifically, the trade and commerce power, backed by the corporations power, although the latter would exclude unincorporated entities such as family farms. Williams advised Xenophon on his private senator’s bill.

Others, particularly in South Australia, feel a referendum is the solution, rectifying the decision made before Federation that rivers be under the control of the new Commonwealth Government. Pyne has been urging a referendum for most of this decade, since well before the Howard Government tried to address the issue in its last term. Birmingham believes there’s a need in the long term for a referendum, but only once its implications are clear, particularly given it is likely to pit the South Australian and Commonwealth Governments against those of NSW, Victoria and Queensland, with Tasmania and Western Australia disinterested observers.

Given the poor record of referenda in Australia, the approach outlined by John Williams would be the safer option, pending an unlikely High Court judgement circumscribing the Commonwealth’s capacity to use the trade and commerce or corporations powers.

Even if Mike Rann wins his case against the Victorians over their water trading cap, that won’t resolve the problem of a dysfunctional interstate water market, into which the Commonwealth is tipping hundreds of millions of dollars. A Commonwealth takeover to establish a level playing field on water would appear to be a priority given water purchasing is the primary tool in efforts to restore the Basin.