The Centre Alliance, which could hold or share the balance of power in the Senate after the election, has announced it will push for a referendum to give the commonwealth power over the Murray-Darling River system, in the wake of multiple scandals over enforcement and questions over spending of the $13bn allocated to the plan.

Rex Patrick, who led a push by the Senate in the last parliament to make the Murray-Darling Basin plan more effective, says giving the federal government a clear mandate to make laws for rivers that flow through more than one state is now essential.

“The water resources of the Murray-Darling Basin and the Great Artesian Basin are of tremendous national importance and must be managed in the national interest,” said Patrick.

“We currently have different water rules in each state, different compliance measures in each state, different governments distributing money for different elements of the Murray-Darling Basin plan, different accountability measures and general opaqueness in the execution and oversight of the plan caused by its multi-jurisdictional nature,” he said.

“Effective national action has been stymied and sidetracked by parochial and vested interests. Our rivers are dying while our federal political system is gridlocked.”

Changing the constitution would require a referendum, and it would likely take time to win support. The first step is for the parliament to pass a bill calling for change.

Centre Alliance’s proposed legislation seeks to put before the Australian people the question of whether the constitution should be amended to give the commonwealth parliament the power to make laws to manage Australia’s national water resources on a consistent basis for the benefit of all Australians while ensuring protection of the environment.

Patrick said the commonwealth had proposed taking control of rivers that crossed state boundaries during the constitutional convention of 1897 but met resistance from the states and they retained control of inland waterways in their state.

“Little progress can be made while vested interests can exert an effective veto through their state governments. Every time changes to the Murray-Darling Basin plan are proposed state water ministers threaten to pull their state out of the basin plan,” he said.

The commonwealth’s oversight of the Murray-Darling Basin plan is currently based on a cooperative agreement and limited commonwealth powers stemming from its power to legislate for interstate trade and commerce and its treaty powers.

It comes as a new report by the Australia Institute sheds more light on Eastern Australian Agriculture’s controversial $80m sale of overland flow rights to the commonwealth in 2017. It also highlights the difficulties of shared responsibilities between the state and commonwealth.

The sale has been under scrutiny because it was concluded without a tender by former agriculture minister Barnaby Joyce. There have been questions about whether the $80m represented good value. The energy minister, Angus Taylor, was a former director and a co-founder of the company, whose holding company is domiciled in the Caymans. Taylor’s business partner in several ventures acted as a consultant on the sale, but says he did this work independent of the companies he owns with Taylor and his brothers.

The price paid to EAA was very much driven by the volume of water that the overland flow licences represent.

“These calculations were made by the vendors themselves, EAA. They appear not to have been verified on site by any commonwealth Department of Agriculture and Water Resources [DAWR],” the Australia Institute concluded after reviewing documents obtained by Guardian Australian under freedom of information laws and by the Senate last year.

The overland flow licences were created by the Queensland government to facilitate the sale of this irregularly available water. The Australia Institute says the Queensland Department of Natural Resources and Mine’s (DNRM) role was limited to comparing EAA’s modelling to its own models.

“Far from expressing concern at the potential conflict of interest of EAA setting their own volume estimates, DAWR seem to have suggested this approach as waiting for DNRM to do this independently could have substantially delayed the purchase,” it says.

“While it is not unusual for landowners to gather information for DNRM, it appears highly unusual for a landowner to do the modelling on DNRM’s behalf.”

The Australia Institute also points out that the commonwealth authorities appear to have been motivated not by price but by the need to meet the water recovery targets in each valley in the basin.

Under the Murray-Darling Basin plan there are targets for each river valley and for each state to return water to the environment.

Joyce took a particular interest in this sale, the documents show, perhaps because he was familiar with the impact it would have on local towns such as St George where he had lived.

The Condamine Balonne target was for 83 % of the 176GL of water to be recovered from Queensland. Because the water is held in relatively few hands in large agribusinesses, the options are limited as to where it can come from.

“The need to recover a relatively large amount of water while under pressure not to take water from irrigation-created incentives to purchase particularly unreliable and difficult-to-use water,” TAI says.

“The EAA transaction would marginally constrain production under higher-flow years, but have virtually no impact under low-flow years when the region is more vulnerable,” NCEconomics noted in a report to the government on the sale.

The Australia Institute also notes that the type of water rights that the commonwealth purchased is an “overland flow licence”.

“This is the right to use water that flows overland during floods, which occur easily in the relatively flat country of the northern Basin. These licences are attached to the land that water flows over, meaning that the commonwealth has no legal control over the water once it flows outside the EAA property – it can be extracted by other users,” senior water researcher Maryanne Slattery said.

“In some cases water savings can potentially be made without reducing water for agriculture by making equipment and infrastructure more efficient. In most cases, however, this has not been the case with some observers suggesting this approach has yielded almost no water for the environment,” she said.

“This has also made fertile ground for creative water accounting and boondoggle projects that have cost taxpayers dearly,” she said.

TAI says that key checks in the process of creation of the licence appear to be deficient, raising questions about the volumes of water the taxpayer has paid for and which will be available to the environment in the future.