New South Wales (NSW) is the most populous state in Australia, with a population of slightly less than eight million. About two-thirds of this population resides in the Greater Sydney Area. The topography of the state is dominated by the Great Dividing Range, a mountain range that extends from north to south, parallel to the Tasman and Coral Seas of the South Pacific Ocean. There are two main categories of rivers in New South Wales: coastal rivers, which rise in the mountain range and flow east towards the sea; and inland rivers, which originate from the opposite side of the mountain and flow west towards the Murray-Darling Basin. The coastal rivers are generally short because of the range's proximity to the ocean, flood during heavy rainfall, and are only navigable in the lower reaches. The longest river in New South Wales is the Murray River.
The Four Longest Rivers in New South Wales
The Murray River is the longest river in New South Wales, as well as the longest in Australia, with a length of 2,508 km (1,558 mi). It rises from the western slopes of the Australian Alps and meanders across the plains, forming the boundary between the state of Victoria and NSW, before draining into Lake Alexandrina, which connects to the Southern Ocean. The Murray River flows through several lakes, creating the Murray River System that provides water to irrigate vast acres of land.
The Murrumbidgee River is the second longest river in both the state and the country, with a length of approximately 1,488 km (923 mi). It is a tributary of the Murray River and is located within the Murray-Darling Basin. The river rises from the foot of Peppercorn Hill, within the Snowy Mountains. It flows for 41 miles through the Australian Capital Territory and is joined by tributaries such as the Cotter, Molonglo, and Queanbeyan Rivers. The Tantangara Dam reduces the river's flow by over 50%, resulting in siltation.
The Darling River is the third longest river in both New South Wales and Australia, with a length of 1,472 km (915 mi). It is also the longest river that flows entirely located within NSW. The Darling River and its tributaries extend for 1,767 miles, making it the longest river system in the continent. It is a major tributary of the Murray River, and much of the Darling River's course flows through Australia's outback, making it a vital source of water.
The Lachlan River is a seasonal river within the Murray-Darling Basin. Its entire course is about 1,440 km (895 mi), and the Lachlan River only connects to the Murray Darling basin during the rainy season, when most of the rivers are flooded. It is the only river in NSW with its entire course located within wetlands.
Conservation of Rivers in NSW
The rivers and wetlands of New South Wales are under extreme pressure after years of catchment degradation, unsustainable water extraction, climate change, and watercourse diversion. For example, the Murray-Darling basin has experienced a decline in its population of native fish and water birds due to the construction of dams. Environmental and nature conservation groups, such as the Nature Conservation Council of NSW, advocate for controlled damming of rivers and the protection of water catchment areas to protect flora and fauna.