Murrumbidgee River

The Murrumbidgee River is a vital waterway in Australia. It is the second longest river in the country. It serves as a major tributary within the Murray–Darling basin. This means it flows into the Murray River, which is another massive river system. The river travels through the Australian Capital Territory and the state of New South Wales.

The name Murrumbidgee comes from the Wiradjuri language. In that language, the name means "big water." This name honors the long history of the river. It flows through the traditional lands of many Aboriginal peoples. These include the Ngarigo, Ngunnawal, Wiradjuri, Nari Nari, and Muthi Muthi peoples.

The river begins its journey in the Snowy Mountains. Its headwaters start at the foot of Peppercorn Hill. This area is part of the Fiery Range along Long Plain. From there, the river flows in a west-northwesterly direction. As it moves, it collects water from many smaller rivers called tributaries. These include the Gudgenby, Queanbeyan, Molonglo, and Cotter Rivers.

The river eventually reaches its confluence, or meeting point, with the Murray River near Boundary Bend. The entire system drains much of southern New South Wales. This makes the river a critical source of irrigation water for the Riverina farming area.

Geologists believe the river has a very ancient history. Some parts of the upper river channels appear to be relatively new in geological terms. These channels may date back to the early Miocene era. The Miocene lasted from 23 million to 5 million years ago. It is suggested that the Upper Murrumbidgee was once an anabranch of the Tumut River. An anabranch is a section of a river that splits off and rejoins the main channel. Geological uplift near Adaminby likely diverted the flow to create the current path. From Gundagai onwards, the river flows within its original ancestral channel.

European explorers arrived in the region during the early 1800s. In 1820, Charles Throsby thought he had found the river. He actually found the Molonglo River instead. In 1823, John Ovens and Mark Currie reached the upper Murrumbidgee. Later, in 1829, Charles Sturt led an expedition down the lower half. His party used a large, stoutly built rowboat. They traveled from Narrandera to the Murray River.

Sturt described the junction of the rivers as a dramatic event. He noted the wild, strong currents that carried his boat into the wide Murray River. In the past, paddle steamers used the river for transport. This trade continued until the 1930s when railways became more common.

Today, human engineering has changed how the river flows. Large dams have been built to manage the water. The Tantangara Dam was completed in 1960 on the headwaters. This dam diverts about 99% of the flow into Lake Eucumbene. Because of this, the river in the Australian Capital Territory is much smaller. It has lost almost 50% of its average annual flow. Other dams, like the Scrivener, Cotter, and Googong Dams, also change the water levels. These changes have serious effects on the environment.

Native fish populations face many challenges due to these modified flows.

A 2008 report by the Murray-Darling Basin Commission highlighted these issues. The report rated the Murrumbidgee in very poor condition. Fish stocks were also rated as extremely poor. Originally, there were 22 native fish species in the river. Now, only 13 of those species can still be found. The reduced water also causes siltation and loss of fish habitats.

This lack of water affects the entire ecosystem. It can even change the local plants. For example, some black box flood plain eucalypt trees are losing their crowns due to changes in flooding.

Flooding is another powerful force on the Murrumbidgee. The river has risen above its banks at Gundagai nine times between 1852 and 2010. The most famous disaster happened in 1852. A massive flood swept away the town of Gundagai. Sadly, 89 people died in that event. This was about one-third of the town's population at the time. The town was later rebuilt on higher ground to stay safe.

While the Burrinjuck Dam has reduced many floods, major events still occur. There were significant floods in 1974, 2010, and 2012. These floods remind us of the river's natural strength.

Many structures now help people live and work near the river. Bridges allow cars and trains to cross the water safely.

There are many important crossings, such as the Sheahan Bridge and the Narrandera Rail Bridge. In the past, movable bridges were needed for paddle steamers to pass. These included opening bridges at Hay, Balranald, and Carathool. The river remains a central part of the landscape for many towns. It connects places like Wagga Wagga, Narrandera, and Hay. The river continues to be a complex system of water, history, and life.