River Torrens

River Torrens
View of Elder Park and Riverside Precinct from Torrens Lake.
Origin	Mount Pleasant, Mount Lofty Ranges
Mouth	Gulf Saint Vincent at Henley Beach South
Length	~85 km (52.8 mi)
Basin area	~500 km2

The River Torrens flows from its source in the Adelaide Hills near Mount Pleasant, across the Adelaide Plains, past Adelaide’s city centre and empties into Gulf St. Vincent at Henley Beach South. The upper stretches of the river and its catchment forms a significant part of Adelaide’s water supply and the linear parks and lake in the lower stretch are iconic of the city. Since European settlement the river has been one of the reasons for the siting of Adelaide, the city’s primary water source, its main sewer (leading to outbreaks of typhus and cholera), and a frequently touted tourist attraction. ^[1]

The river is also known by the indigenous Kaurna people’s name of Karrawirraparri (meaning red gum forest river), referring to the dense eucalypt forest that lined its banks prior to clearing by early Europeans. The first European sighting of the river was in November 1836 by a party including G.S. Kingston with Governor John Hindmarsh naming the river in 1837 after Colonel Robert Torrens, chairman of the South Australian colonisation commissioners. ^[2]

The River today

From its source the river flows westwards through Birdwood and Gumeracha . The river’s flow is captured by the Happy Valley, Millbrook and Kangaroo Creek reservoirs, which provide water storage for Adelaide. It then continues down through Torrens Gorge entering suburban Adelaide at the suburb of Athelstone with some of its path paralleled by the O-Bahn Busway. It passes between the Adelaide city centre and North Adelaide, forming the Torrens Lake between the Adelaide Zoo and a weir opposite Adelaide Gaol. The river then continues the remaining eight kilometres to the sea at Henley Beach South, emptying into Gulf St. Vincent via a constructed outlet.

The river’s catchment area of approximately 500 sq km is the largest of any waterway within the Adelaide region. The upper reaches are used to create a potable water supply for metropolitan Adelaide with the river supplying three of Adelaide’s eight reservoirs.^[1] The upper catchment has an average annual rainfall of between 575mm, at its eastern end, to 1025mm near Uraidla.^[3]

The suburban end of the river is bounded by 35km of linear parks, with numerous playgrounds walkways and bicycle tracks, which were constructed for flood mitigation and represent the earliest linear river park in Australia. On the south bank of the lake adjacent to the Adelaide Festival Centre is Elder Park, a European style landscaped park with an ornamental rotunda. The park is used for the annual Tasting Australia festival, mass singing of Christmas carols by candlelight as well as other public events throughout the year. The Popeye tourist boat, small paddle boats and black swans of the lake are icons of the area frequently featured in postcard photographs of the city. Due to now limited natural river flow and stormwater born organic material the lower river, particularly the lake, is often polluted with algal blooms and significant levels of E. coli bacteria in spring and summer. Numerous taskforces have been formed to improve the river’s water quality in with the latest created by the Minister for the Environment and Conservation in 2006.^[4]

Prior to european settlement

As discovered by Europeans, the river was a summertime chain of waterholes bounded by large gum trees. As it flowed through the area where the city of Adelaide is sited, the flow of the river sometimes was invisible beneath the gravel stream bed. The river frequently flooded in winter and did not reach the sea, instead ending at coastal dunes where it’s waters created a vast but shallow freshwater wetland. The wetlands, known as The Reedbeds after the dominant vegetation, occupied a large area of the western Adelaide Plains and were also fed by other waterways.^[1] The river only flowed to the sea through the Port River, Barker Inlet, and Patawalonga Creek following heavy rain.^[5]

Human wrought changes

Weir forming the Torrens Lake near Adelaide Gaol

In 1860 with water cartage being inadequate for good supply, the first reservoir was constructed at Thorndon park partway through the river’s suburban flow. On 28 Dec 1860 piped water supply from the reservoir began and by 1872 the Hope Valley reservoir, in the Adelaide hills foothills, was also in use. ^[6]

During early years of colonization, the surrounding trees where cut down and the river’s gravel used in road making and building construction. As the natural environment was removed, the banks were eroded and the river bed gradually levelled as the the waterholes filled. By 1878 the river was noted to be a malodorous, black sewer rather than the sylvan stream of the 1830’s.^[2] The Torrens lake was created in 1881 with the construction of a weir and the landscaping of Elder park and the river’s bank. In 1934 work began to divert the river at Lockleys (near Adelaide Airport ) , with the original channel blocked and a new channel ( called Breakout Creek ) created to the sea.^[1] This was funded through an unemployment grant, and State and Local Government contributions to reduce the occurrence and severity of flooding. .^[5] The Wetlands was subsequently drained and is now the site for the suburb of West Lakes.

Most of the river's catchment area is comprised of cleared farmland with runoff captured in private dams to sustain farming over Adelaide's dry summer. Combined with the river's use for potable water this has greatly reduced the overall river flow and reduced summer flow in the lower river to a trickle.

Flora and Fauna

The river was formerly a food source with yabbies, mussels and small fish however the reduction in water quality, changing of the river’s habitat, and introduction of European fish species has lead to a reduction in fauna quantity and diversity. ^[2] Exotic pest species such as the European carp, Trout and Redfin Perch have greatly reduced native fish populations like the big headed gudgeon but waterbirds and waterfowl are common along the river with ducks, ibis, egrets and herons amongst the more than 100 species seen. In places the steep banks of the river formed an ideal habitat for long-necked tortoises.

Common native reeds, sedges and rushes along the upper river are bulrush, knobby club rush, spike rush, common reed, [[Juncus|sea rush and pale rush, and sedge.

Bridges

Due to rivers path through the city centre, transport necessitated the construction of many bridges including:

• 1845, Hackney Bridge, also known as the Company Bridge, was built so that wheat farmers from the northern side could access the South Australian Company's flour mill which occupied the site where the Hackney Hotel now stands.
• 1856, Railway Bridge, Port and Gawler Town lines, 74 chains (approx. 1.5 km) from the Adelaide Station^[7]
• 1859, Old Frome Bridge, now known as the Albert Bridge was built adjacent to the Adelaide Zoo on Frome Road.
• 1873, Felixstowe Bridge, on OG Road, reconstructed in 1892, 1901, 1924 and 1961. The first bridge was narrow, and hay-laden carts often brushed the posts, damaging them.
• 1877, Tennyson Bridge, on Stephen Terrace, replacing a ford which stood there.
• 1937, University Footbridge between Adelaide Uni and Peace Park ^[8]
• 1970, Ascot Bridge, built to connect Ascot Avenue and Lower Portrush Road.
• 1977, Dickson's Crossing, on Darley Road, replacing a ford.

Events

The river was the site of a notorious murder, in which on 10 May 1972 University of Adelaide law lecturer Dr George Duncan was thrown into the river, adjacent to the university. A plaque exists near the location commemorating his death and the subsequent decriminalisation of homosexuality in South Australia.

Notes

References

External links

• Torrens Catchment Water Management Board
• State Library Manning Index: River Torrens

Categories

Find

Find