Riverina

The Riverina is a highly productive agricultural region in south-western New South Wales, Australia.

It is defined by its flat plains and a climate with significant seasonal variation. An ample supply of water for irrigation makes this area unique among Australian regions. This combination of geography and water allows for diverse farming. The region is part of the massive Murray-Darling Basin.

The geography of the Riverina is shaped by ancient natural processes. The land is primarily an alluvial plain. This means it was formed by sediment deposition. Streams carried material from the Great Dividing Range between 30,000 and 15,000 years ago. To the east, the terrain features rolling hills. As you move west, the land becomes much flatter. Most of this western plain sits at a low elevation. The far western section consists of featureless saltbush plains.

Water systems are the lifeblood of the Riverina's economy and ecology. The region is drained by the Murray and Murrumbidgee rivers. These rivers flow generally from east to west. Other important streams include Billabong Creek and the Edward River. The Edward River is an anabranch of the Murray. Much of this water is diverted for human use. In 2001–2002, 52% of the runoff from these rivers was diverted. Of that diverted water, 77% was used specifically for irrigation.

The climate in the Riverina is classified as a Hot Dry Zone. This means summers are very hot. However, winters can be quite cold with mild days. Under the Köppen climate classification, it is mostly a hot-summer Mediterranean climate. Some western areas have a semi-arid climate. Eastern areas show humid subtropical tendencies. Rainfall is generally low across the region. The median annual rainfall is between 300 and 400 mm. This rises to 500–600 mm on the eastern fringe.

Human history in the Riverina spans tens of thousands of years. Aboriginal groups, including the Wiradjuri people, have inhabited the area for over 40,000 years. Other groups like the Nari-Nari and Yorta Yorta also lived here. The rivers were vital for food and communication. People used bark canoes to travel the waterways. Scars on trees near rivers provide evidence of this use. European exploration began in the early 19th century. John Oxley explored the Lachlan River in 1817. Charles Sturt followed the Murrumbidgee between 1828 and 1831.

Following exploration, the region became a major pastoral center. In the mid-19th century, Europeans established runs for beef and wool. Early stations like "Cocketgedong" were very large. Some properties reached sizes of 65,000 acres. In the 20th century, irrigation changed the landscape again. This allowed for new crops like rice and wine grapes. Major population centers grew to support these industries. Cities like Wagga Wagga, Leeton, Griffith, and Albury serve as service hubs. Wagga Wagga hosts a Charles Sturt University campus.

The Riverina's ecology supports a wide variety of life. River channels host river red gum and River Cooba communities. Higher areas contain black box woodlands. The treeless plains feature saltbush and native grasslands. Many mammals, such as Sugar Gliders and Koalas, live in these habitats. The wetlands also support many migratory bird species. However, land clearing and grazing have impacted native diversity. The region remains a vital link in Australia's agricultural and natural systems.