A huge plain that lies in the southern part of the Murray-Darling Basin. It was formed from sediment deposited by the Murray, Murrumbidgee, Lachlan and Goulburn Rivers which flow west through the Riverina bioregion from the Great Dividing Range. Landscapes are a mosaic of woodlands interspersed with grasslands, which occur on heavy less well drained red-brown and grey clay soils, and ephemeral or seasonal wetlands on depressions and drainage lines.
Semi-arid with hot summers and cool winters. Rainfall is highly variable from year to year. Summer rainfall tends to occur mainly from localised thunderstorms, with more consistent rainfall occurring in the winter months. Annual rainfall tends to increase from west to east and from north to south and is between 300 to 500 mm / year
Natural grasslands of the Murray Valley Plains; Seasonal Herbaceous Wetlands (Freshwater) of the Temperate Lowland Plains