A royal commission into the Murray-Darling basin plan called by South Australia could become a de facto national inquiry into the river system, after the commission made clear it intends delve into issues across the basin and invite witnesses from other states.

But whether other states and the federal government will cooperate remains to be seen.

The Guardian has been told the federal government plans to ask Stephen Marshall, the newly elected Liberal premier of SA, to wind back the terms of reference of the inquiry.

As to whether it will permit federal bureaucrats to appear and give evidence, a spokesman for the commonwealth, speaking on behalf of the Department of Agriculture and the Murray-Darling Basin Authority, said “the commonwealth will inform the South Australian royal commission of its position directly, before making public comment on this issue”.



A spokesperson for the NSW minister for industry and regional water, Niall Blair, said NSW would respond to written questions “it considers relevant” from the commission “where appropriate and subject to our own legal advice”.



The SA royal commission, which is being headed by NSW QC Bret Walker, has already begun informal consultations and intends to travel to all four basin states to meet with communities before beginning formal hearings. It held a community forum in Murray Bridge last week.



It has also written to more than 300 interested parties, including state and federal agencies and governments, asking them to make submissions.

Releasing an issues paper today, the commission said it was not convened to advocate for South Australia, which at the end of the Murray-Darling system has experienced greater impacts from irrigation. Instead it will be inquiring into the entire basin.



“While the commission was established by the governor of South Australia, it is important to note the commission is independent of government, it does not take direction from government as to the methods of its information gathering, the finding of facts it may make, the opinions it may express, or the recommendations it ultimately makes,” the paper says.

“The commission does not represent South Australia and, in simplistic terms, does not take a position ‘for’ South Australia, or ‘against’ any other basin state.”

The commission said its expectation was that it would receive cooperation and assistance from people, organisations and government departments.

But it did not rule out compelling production of documents or appearances by summons if necessary, which potentially could set the scene for a major constitutional stoush should the commonwealth or other states resist.



Among the issues the commission says it wants to explore is how the Murray-Darling Basin Authority (MDBA) came up with its figure of an environmentally sustainable level of take from the system by irrigation.

The commission wants to hear from the MDBA about its methodology and how it interprets its responsibilities under the federal water act.

It also wants to explore the changes to the plan currently being proposed. One has already been disallowed by the Senate but the issue is expected to return to the Senate on 7 May.

The MDBA wants to change how much water is recovered for the environment in the Northern Basin and is proposing a 70GL cut. It has argued that its decisions should take account of the economic impacts, as well as environmental ones, of water buybacks on farming communities.

It will also be looking into the 36 projects that have been proposed for the Southern Basin mainly by NSW and Victoria as a way of delivering greater environmental flows – without having to withdraw more volumes of water from irrigation. These include projects to manage the rivers and dams differently.

It will also be inquiring into the proposed 450GL increase that South Australia is desperate to see to the 2,750 GL environmental water recovery target. The commission notes this is meant to be achieved through efficiency projects funded with $1.77bn of commonwealth money but farmers appear to have little understanding of how this will work.

It will also be delving into how the MDBA calculates the figure of 2,106GL it says has already been recovered for the environment.

The Guardian and others have raised questions about the reliability of water purchased by the commonwealth for the environment.

The commission also intends to inquire into “what extent that return has been compromised by illegal take”, which means the inquiry will be delving into allegations of water theft as well.

It has particularly highlighted an interest in the Darling river and Menindee lakes which have seen algal blooms again this summer as the river ceased to flow.

One interesting tangent will be the commission’s investigation into the powers of the commonwealth to potentially take over management of the Murray-Darling basin. Walker, a noted constitutional lawyer, is said to be interested in the scope for more commonwealth control.

Australia has signed environmental treaties to protect endangered species and environments, which provides a potential head of power for the commonwealth to take over.