Climate Change and Water Minister, Penny Wong, announced yesterday that $303 million would be spent to buy Twynam’s river water – the biggest purchase of water in the nation’s history.

This was expected to include water from 'Merrowie' and 'Brooklyn', north of Hillston, which produced cotton, grains, maize, oilseeds, cattle and wool.

It was unknown whether it would also encompass 'Jemalong' (grains, maize, oilseed, cattle and citrus) or a feedlot and grain production enterprise, 'The Mount', both west of Forbes.

Chief executive of Lachlan Valley Water, Mary Ewing, said a one-in-twenty-year flood would be needed to push water from the Lachlan River into the Murrumbidgee, which in turn runs into the Murray.

"That would be five to six million megalitres but our long term average in the Lachlan is 1.2 million megalitres," she said.

"That's a very large flow.

"The water bought from the Lachlan will not help South Australia or the Lower Lakes.

"Only about 15pc of the Lachlan's flow was pumped out this year and that included town use."

Environmental uses in the Lachlan system would be the wetlands downstream of Hillston, such as the Great Cumbung Swamp and the Booligal Wetlands.

Ms Ewing said that once the drought ended, a water sharing plan already in place, had allocated water for environmental flows.

Mayor of Carrathool Shire Council, Peter Laird, whose shire encompasses much Lachlan River country in southern NSW, 'Merrowie' and 'Brooklyn', is concerned about the economic flow-on affects of the major asset being taken out of the community.