The failure of the Murray Darling Basin Plan

The barrages block sea water from entering the lakes, thus ensuring they only contain fresh water from the Murray. This prevents tidal flows from keeping the Murray mouth open, which is now quite silted and requires almost constant dredging.

Somewhere around 800-900 GL simply evaporates in the lower lakes. This is fresh water worth hundreds of millions of dollars in the water trading market, delivered from the eastern states via the Murray River, that evaporates into the atmosphere for zero environmental benefit.

Evaporation is unavoidable, but if the Murray mouth was open and the sea was free to enter the lakes, it could be seawater (or at least a mixture of fresh and seawater) that evaporated instead.

In this unreal world of environmental politics, it is assumed that sending more and more water down the Murray is somehow good for the environment and will keep the Murray mouth open. As is now apparent, this is completely wrong. Water only benefits the environment when it is present in the right place, in the right quantities, at the right time.

Put simply, the MDBP is perpetuating an artificial environment in SA at the expense of Australian farming and rural communities. The loss of water for irrigation in southern Queensland, NSW and Victoria has devastated many regional communities, while its wasteful loss in South Australia is unforgiveable.

Perhaps the environment is marginally better off in a few limited areas but, in terms of overall benefit, it is probably worse off.

What ought to happen is for the SA government to demolish the barrages and remove Bird Island, a sand island that has formed in the mouth of the Murray as a result of the effect of the barrages. This would allow the Murray to run free.

If a new weir was built across the Murray near Wellington to prevent seawater from moving too far up the river and contaminating either Adelaide's supply in dry years, even a repeat of the Millenium Drought would be of no concern. Lakes Albert and Alexandrina would simply become intermittently saline and, with the Murray mouth open, the long-suffering Coorong would recover.

The MDBP was always a political solution to a political problem, but its consequences are not minor. We are long overdue for a dose of non-political reality.