Swan River (Western Australia)


The Swan River is a river in the south west of Western Australia. Its Aboriginal Noongar name is the Derbarl Yerrigan. The river runs through the metropolitan area of Perth, Western Australia's capital and largest city.

Course of river

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. It has three major tributaries, the Avon River, Canning River and Helena River. The latter two have dams which provide a sizeable part of the potable water requirements for Perth and the regions surrounding. 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, southeast of Perth: it meanders north-northwest to Toodyay about 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 not far from North Bannister, 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 Noongar people believe that the Darling Scarp represents the body of a Wagyl – a snakelike being from Dreamtime that meandered over the land creating rivers, waterways and lakes. It is thought that the Wagyl/Waugal created the Swan River.
The estuary is subject to a microtidal regime, with a maximum tidal amplitude of about, although water levels are also subject to barometric pressure fluctuations.

Geology

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.

Geography

The Swan River drains the Swan Coastal Plain, a total catchment area of over in area. The river is located in a Mediterranean climate, with hot dry summers and cool wet winters, although this balance appears to be changing due to climate change. The Swan is located on the edge of the Darling Scarp, flowing downhill across the coastal plain to its mouth at Fremantle.

Tributaries

More tributaries including Ellen Brook, Jane Brook, Henley Brook, Wandoo Creek, Bennett Brook, Blackadder Creek, Limestone Creek, Susannah Brook, and the Helena River enter the river between Wooroloo Brook and Guildford; however, most of these have either dried up or become seasonally flowing due to human impacts such as land clearing and development.

Swan coastal plain

Between Perth and Guildford the river goes through several loops. Originally, areas including the Maylands Peninsula, Ascot and Burswood, through Claise Brook and north of the city to Herdsman Lake were swampy wetlands. Most of the wetlands have since been reclaimed for land development. Heirisson Island, upon which The Causeway passes over, was once a collection of small islets known as the Heirisson Islands.

Perth Water and Melville Water

, between the city and South Perth, is separated from the main estuary by the Narrows, over which the Narrows Bridge was built in 1959. The river then opens up into the large expanse of the river known as Melville Water. The Canning River enters the river at Canning Bridge in Applecross from its source south-east of Armadale. The river is at its widest here, measuring more than from north to south. Point Walter has a protruding spit that extends up to into the river, forcing river traffic to detour around it.

Narrowing and Fremantle

The river narrows between Chidley Point and Blackwall Reach, curving around Point Roe and Preston Point before narrowing into the harbour. Stirling Bridge and the Fremantle Traffic Bridge cross the river north of the rivermouth. The Swan River empties into the Indian Ocean at Fremantle Harbour.

Notable features

Plant and animal life found in or near the Swan-Canning Estuary include:
The river was named Swarte Swaene-Revier by Dutch explorer, Willem de Vlamingh in 1697, after the famous black swans of the area. Vlamingh sailed with a small party up the river to around Heirisson Island.
A French expedition under Nicholas Baudin also sailed up the river in 1801.
Governor Stirling's intention was that the name "Swan River" refer only to the watercourse upstream of the Heirisson Islands. All of the rest, including Perth Water, he considered estuarine and which he referred to as "Melville Water". The Government notice dated 27 July 1829 stated "... the first stone will be laid of a new town to be called 'Perth', near the entrance to the estuary of the Swan River."
Almost immediately after the Town of Perth was established, a systematic effort was underway to reshape the river. This was done for many reasons:
Perth streets were often sandy bogs which caused Governor James Stirling in 1837 to report to the Secretary of State for Colonies:
At the present time it can scarcely be said that any roads exist, although certain lines of communication have been improved by clearing them of timber and by bridging streams and by establishing ferries in the broader parts of the Swan River...

Parts of the river required dredging with the material dumped onto the mud flats to raise the adjoining land. An exceptionally wet winter in 1862 saw major flooding throughout the area – the effect of which was exacerbated by the extent of the reclaimed lands. The first bucket dredge in Western Australia was the Black Swan, used between 1872 and 1911 for dredging channels in the river, as well as reclamation.

Notable features

A number of features of the river, particularly around the city, have reshaped its profile since European settlement in 1829:
The river has been used for the disposal all kinds of waste. Even well into the 1970s various local councils had rubbish tips on the mud flats along the edge of the river. Heavy industry also contributed its share of waste into the river from wool scouring plants in Fremantle to fertiliser and foundries sited in the Bayswater – Bassendean area. Remedial sites works are still ongoing in these areas to remove the toxins left to leach into the river.
During the summer months there are problems with algal blooms killing fish and caused by nutrient run-off from farming activities as well as the use of fertilisers in the catchment areas. The occasional accidental spillage of sewage and chemicals has also caused sections of the river to be closed to human access. The river has survived all this and is in relatively good condition considering on-going threats to its ecology.
In 2010 the Western Australian government imposed restrictions on phosphorus levels in fertilisers due to concerns about the health of the Swan and Canning river system.
The Perth Water location on the river adjacent to the City of Perth is a popular place for viewing the annual Australia Day fireworks, with over 400,000 people crowding the foreshore, Kings Park and boats on the river.

Flood events

Data collection of flood events in the estuary have been recorded since European arrival in 1829. In July 1830, barely a year after the establishment of the colony, the river rose 6 metres above its normal level. New settlers were still arriving in steady numbers and few permanent buildings had been constructed, with most living in tents and other temporary accommodation. These included caves along the river's edge and many found their belongings washed away and livestock drowned. Other abnormal floods events occurred in the winters of 1847 and 1860, while the most recent flooding occurred in 2017. Later events have since been assessed for probability of recurrence:
Year18621872191019171926193019451946195519581963196419832017
ARI*601002020301520102020151010TBC

* ARI is the average interval in years which would be expected to occur between exceedances of flood events of a given magnitude.
The largest recorded flood event was in July 1872 which had a calculated ARI of 100. This approximately equates to a 100-year flood event. At the Helena River, the 1872 flood level was two feet 3 inches higher that the 1862 event. An account in The Perth Gazette and Western Australian Journal on 26 July 1872 reported
In and about Perth, the water owing to the force of the incoming seas at the mouth of the river presented a scene of a great lake, all the jetties were submerged, the high roads to Fremantle covered, and passage traffic rendered impossible quantities of sandalwood lying along the banks of river were washed away, and the inhabitants of the suburban villas on the slopes of Mount Eliza obliged to scramble up the hill sides to get into Perth.

The flood of July 1926 resulted in the washing away of the Upper Swan Bridge and a section of the Fremantle Railway Bridge. The Fremantle bridge partially collapsed on 22 July 1926, five minutes after a train containing schoolchildren had passed over. No one was injured in the collapse, however it created major disruption to commerce for several months. Repairs were completed and the bridge reopened on 12 October 1926.

Governance

The Swan River Trust is a state government body, within the ambit of the Department of Environment and Conservation – 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.
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.

Human uses

Transport

In the earliest days of the Swan River Settlement, the river was used as the main transport route between Perth and Fremantle. This continued until the establishment of the Government rail system between Fremantle and Guildford via Perth.
along Blackwall Reach towards Point Walter and Perth

Bridges

There are currently 22 road and railway bridges crossing the Swan River. These are :
  1. Fremantle Railway Bridge, North Fremantle to Fremantle
  2. Fremantle Traffic Bridge, North Fremantle to Fremantle
  3. Stirling Bridge, North Fremantle to East Fremantle
  4. Narrows Bridge, South Perth to Perth – northbound
  5. Narrows Bridge, Perth to South Perth
  6. Narrows Bridge, Perth to South Perth – southbound
  7. The Causeway, Perth to Heirisson Island
  8. The Causeway, Heirisson Island to South Perth
  9. Matagarup Bridge, East Perth to Perth Stadium, Burswood
  10. Goongoongup Bridge, East Perth to Burswood
  11. Windan Bridge, East Perth to Burswood,
  12. Garratt Road Bridge, Bayswater to Ascot – northbound
  13. Garratt Road Bridge, Ascot to Bayswater – southbound
  14. Redcliffe Bridge, Bayswater to Ascot
  15. Bassendean Bridge, Bassendean to Guildford
  16. Guildford Railway Bridge, Bassendean to Guildford
  17. Barkers Bridge, Guildford to Caversham
  18. Whiteman Bridge, Caversham to Middle Swan
  19. Maali Bridge, Henley Brook to Herne Hill
  20. Yagan Bridge, Belhus to Upper Swan
  21. Upper Swan railway bridge, Upper Swan
  22. Bells Rapids bridge, Upper Swan to Brigadoon

Rowing clubs

The earliest club was the West Australian Rowing Club. The Swan River Rowing Club started in 1887. The Fremantle Rowing Club had started by the 1890s.

Yacht clubs

There are currently fifteen yacht clubs along the Swan River, with most on Melville Water, Freshwater Bay and Matilda Bay. Royal Perth Yacht Club, on Pelican Point in Matilda Bay, staged the unsuccessful 1987 America's Cup defence, the first time in 132 years it had been held outside of the United States. RPYC and the Royal Freshwater Bay Yacht Club are the only two clubs to be granted a royal charter. There are also many anchorages and marinas along the lower reaches near Fremantle.

Cultural significance

There have been some north of the river or south of the river distinctions in the Perth metropolitan region over time, especially in the time up to the completion of the Causeway and Narrows bridges, due to the time and distances to cross the river.
The river is a significant part of Perth culture, with many water sports such as rowing, sailing, and swimming all occurring in its waters.
It is also the site of the City of Perth Skyworks, a fireworks show held each year on Australia Day.