Federal Water Minister Malcolm Turnbull had no choice but to reject out of hand new calls by the Wentworth Group to buy back a portion of each and every water licence in the Murray Darling Basin.

The politics of the situation said so.

With an election due in the next four months and the Coalition lagging badly in the polls, picking a fight with its core rural and regional constituency is simply not an option.

If Mr Turnbull had, by some strange leap of logic, followed the advice of Wentworth economist Mike Young, he would also have been picking a fight with The Nationals.

In their seat-by-seat fight for survival, The Nationals are itching for an issue that could galvanise support for the party in the bush at this year's election.

But given Prime Minister John Howard's strong belief in the Coalition, it would be a political fight Mr Turnbull would most likely lose - Mr Howard would bend over backwards on the issue if it meant keeping The Nationals happy at this critical stage of an election year.

But politics aside, there are other good social, economic and scientific reasons why Mr Turnbull should reject the advice.

Firstly, the obvious social and economic impact such a move would have on the small town economies of the Murray Darling Basin which are dependent on irrigation.

Such towns - many already struggling - would be at risk of collapse.

Further it should also be remembered that Mr Young is now saying that 5000 gigalitres of irrigation water is needed to revive the rivers' fortunes - that figure is a huge jump on what the Australian community has been told for several years.

Previously Labor and green groups have pushed for 1500GL to be returned from irrigators as environmental flows.

The Commonwealth's $10 billion plan trumped that to 3000GL - it's a figure it says can be achieved through investment in infrastructure and efficiency projects which would ensure farm productivity is not lost by splitting water savings 50/50 between irrigators and the environment.

But all of these details are still moot if Victoria does not sign on for the $10B project - winning that battle is the first and foremost political victory Mr Turnbull needs.

What do you think?