Documents disclose how Victoria wants to return less than 1800 billion litres of water to the ailing Murray-Darling River system.

The revelation has angered environmental groups and the Weatherill Government.

The amount is less than half what scientists believe is necessary to save the Murray and, environmentalists claim, would leave South Australian river communities devastated.

The MDBA is due to release the updated version of its plan today after receiving feedback from all the states.