Swan River (Western Australia)
The Swan River (Nyungar: Derbarl Yerrigan[2][3]) is a major river in the southwest of Western Australia. The river runs through the metropolitan area of Perth, Western Australia's capital and largest city.
This article is about the river in Western Australia. For the British settlement established in 1829, see Swan River Colony.
Swan River
Nyungar: Derbarl Yerrigan
Avon River with Wooroloo Brook
below Mount Mambup
53 m (174 ft)
0 m (0 ft)
72 km (45 mi)
121,000 km2 (47,000 sq mi)
Susannah Brook, Jane Brook
Course of river[edit]
The Swan River estuary flows through the city of Perth. Its lower reaches are relatively wide and deep, with few constrictions, while the upper reaches are usually quite narrow and shallow.
The Swan River drains the Avon and coastal plain catchments, which have a total area of about 121,000 square kilometres (47,000 sq mi). It has three major tributaries, the Avon River, Canning River and Helena River. The latter two have dams (Canning Dam and Mundaring Weir) which provide a sizeable part of the potable water requirements for Perth and the surrounding regions. The Avon River contributes the majority of the freshwater flow. The climate of the catchment is Mediterranean, with mild wet winters, hot dry summers, and the associated highly seasonal rainfall and flow regime.
The Avon rises near Yealering, 221 kilometres (137 mi) southeast of Perth: it meanders north-northwest to Toodyay about 90 kilometres (56 mi) northeast of Perth, then turns southwest in Walyunga National Park – at the confluence of the Wooroloo Brook, it becomes the Swan River.
The Canning River rises from North Bannister, 100 kilometres (62 mi) southeast of Perth and joins the Swan at Applecross, opening into Melville Water. The river then narrows into Blackwall Reach, a narrow and deep stretch leading the river through Fremantle Harbour to the sea.
The estuary is subject to a microtidal regime, with a maximum tidal amplitude of about 1 metre (3 ft 3 in), although water levels are also subject to barometric pressure fluctuations.
Geology[edit]
Before the Tertiary, when the sea level was much lower than at present, the Swan River curved around to the north of Rottnest Island, and disgorged itself into the Indian Ocean slightly to the north and west of Rottnest. In doing so, it carved a gorge about the size of the Grand Canyon. Now known as Perth Canyon, this feature still exists as a submarine canyon near the edge of the continental shelf.
Plant and animal life found in or near the Swan-Canning Estuary include:
Governance[edit]
The Swan River Trust is a state government body, within the ambit of the Department of Environment and Conservation (Western Australia) – that was constituted in 1989 after legislation passed the previous year, that reports to the Minister for the Environment. It brings together eight representatives from the community, State and local government authorities with an interest in the Swan and Canning rivers to form a single body responsible for planning, protecting and managing Perth's river system.[18][19]
The Trust meets twice a month to provide advice to the Minister for the Environment, the Western Australian Planning Commission and river border related local government bodies to guide development of the Swan and Canning rivers.
