 One method of classification of boundaries for the Riverina is the Interim Biogeographic Regionalisation for Australia that defines the bioregion as an area comprising 9 @,@ 704 @,@ 469 hectares ( 23 @,@ 980 @,@ 270 acres ) , with biogeographic subregions covering each of the Lachlan , Murrumbidgee , Murray Fans , Victorian Riverina , Robinvale Plains , and Murray Scroll Belt . 
