The Swan Coastal Plain in

Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to th ...

is the geographic feature which contains the Swan River as it travels west to the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by th ...

. The

coastal plain A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Coa ...

continues well beyond the boundaries of the Swan River and its tributaries, as a geological and biological zone, one of Western Australia's

Interim Biogeographic Regionalisation for Australia The Interim Biogeographic Regionalisation for Australia (IBRA) is a biogeographic regionalisation of Australia developed by the Australian government's Department of Sustainability, Environment, Water, Population, and Communities. It was devel ...

(IBRA) regions.IBRA Version 6.1
data It is also one of the distinct physiographic provinces of the larger West Australian Shield division.

Location and description

The coastal plain is a strip on the Indian Ocean coast directly west of the

Darling Scarp The Darling Scarp, also referred to as the Darling Range or Darling Ranges, is a low escarpment running north–south to the east of the Swan Coastal Plain and Perth, Western Australia. The escarpment extends generally north of Bindoon, to t ...

uplands running from

Cape Naturaliste Cape Naturaliste is a headland in the south western region of Western Australia at the western edge of the Geographe Bay. It is the northernmost point of the Leeuwin-Naturaliste Ridge which was named after the cape. Also the Leeuwin-Naturaliste ...

in the south to north of the city of

Perth Perth is the capital and largest city of the Australian state of Western Australia. It is the fourth most populous city in Australia and Oceania, with a population of 2.1 million (80% of the state) living in Greater Perth in 2020. Perth is ...

. The plain mainly consists of fairly infertile sandy soil along with coastal sand dunes, river estuaries, and a number of wetlands kept back from the sea by the dunes. A number of rivers cross the plain from east to west from the Darling Scarp towards the sea, including the Swan and its main tributary, the

Canning Canning is a method of food preservation in which food is processed and sealed in an airtight container (jars like Mason jars, and steel and tin cans). Canning provides a shelf life that typically ranges from one to five years, although u ...

. The sediments of the

Perth Basin The Perth Basin is a thick, elongated sedimentary basin in Western Australia. It lies beneath the Swan Coastal Plain west of the Darling Scarp, representing the western limit of the much older Yilgarn Craton, and extends further west offshore. C ...

are Tertiary and Quaternary in age immediately below Perth and include coquina,

travertine Travertine ( ) is a form of terrestrial limestone deposited around mineral springs, especially hot springs. It often has a fibrous or concentric appearance and exists in white, tan, cream-colored, and even rusty varieties. It is formed by a p ...

, and sandy limestones with abundant shelly material. Perth is sited on a set of sand dunes formed during the Pliocene-Pleistocene during the last

ice age An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages and gree ...

. Offshore, the sand dune system and surficial deposits transition into a system of partly eroded limestones and sandy limestones. These form a series of drowned

cuesta A cuesta (from Spanish ''cuesta'' "slope") is a hill or ridge with a gentle slope on one side, and a steep slope on the other. In geology the term is more specifically applied to a ridge where a harder sedimentary rock overlies a softer laye ...

s which today form submerged reefs. Because of the steepness and orientation of the Darling Scarp, watercourses run off the scarp in a westerly direction. On reaching the Swan Coastal Plain, they encounter two obstacles: firstly, the high permeability of the soil results in the loss of much water. Much flow is lost, and some watercourses simply cease to flow, for example, Wungong Brook,

Cardup Brook Cardup is an outer suburb of the Western Australian capital city of Perth, located in the Shire of Serpentine-Jarrahdale The Shire of Serpentine-Jarrahdale is a local government area in the outer southeastern metropolitan area of Perth, the ...

, and Manjedal Brook. Secondly, the sequence of north-to-south-oriented dunes create obstacles to further westerly flow. Many watercourses turn at right angles and flow south or north along the dune swales, and in some cases this allows multiple watercourses to coalesce. For example, on reaching the coastal plain,

Ellen Brook Ellen Brook is an ephemeral stream which runs from south of Gingin to the Swan River in Western Australia. Overview The headwaters of Ellen Brook start south of Gingin, in the Wheatbelt region. From there, Ellen Brook travels south, gener ...

runs south for around , picking up a number of watercourses along the way, before finally emptying into the Swan River. Another example is the Serpentine River, which runs west to less than from the coast, then turns south, running parallel with the coast for nearly before disgorging into

Peel Inlet The Peel-Harvey Estuarine System ( nys, Djilba) is a natural estuarine system that lies roughly parallel to the coast of Western Australia and south of the town of Mandurah. The strip of land between the Indian Ocean and the estuarine system c ...

Coastal dunes and Wanneroo wetlands

The dune topology also results in extensive north-to-south-oriented chains of wetlands, again located in the swales. For example, the chain of lakes north of Perth includes lakes of the

Wanneroo wetlands The Wanneroo wetlands are a series of wetlands, swamps and lakes that occur on the Swan Coastal Plain of Perth, Western Australia. They are linked very closely to the Gnangara Mound. They are in part, incorporated into the Yellagonga Regiona ...

including –

Lake Pinjar A lake is an area filled with water, localized in a basin, surrounded by land, and distinct from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, although, like the much larger ...

, Jandabup Lake and Gnangara Lake. The large bodies of water in the estuary of the Swan River,

Perth Water Perth Water is a section of the Swan River on the southern edge of the central business district of Perth, Western Australia. It is between the Causeway to the east, and Narrows Bridge to the west – a large wide but shallow section of river, ...

and

Melville Water Melville Water is a significant section of the Swan River in Perth, Western Australia. It is located west and downstream of Perth Water, from which it is separated by the Narrows Bridge. Name Melville Water was named in 1827 by Captain Jame ...

are also located in dune swales.

Geology

The Swan coastal plain is characterised by a series of sand dune systems, the Quindalup dunes, the Spearwood dunes, and the Bassendean dunes, which run from west to east (in increasing age) from the coastline to the major faults which form the eastern boundary of the plain. The plain is bounded to the east by the

, to the north by a subsidiary fault running north-west from Bullsbrook, and to the south by the Collie-Naturaliste Scarp. The Pinjarra plain lies between the Bassendean dunes and the eastern scarps. Early work on all three dune systems considered them to have been formed at differing times by the deposition of sands carried by wind ( aeolian and/or by river processes (fluviatile).R.B. Salama, D.W. Pollock, J.D. Byrne and G.W. Bartle. 2000
Geomorphology, Soils and Landuse in the Swan Coastal Plain in relation to Contaminant Leaching
Agrochemical Pollution of Water Resources, Proceedings of a Conference held on 16–18 February 2000 at Hat Yai, Thailand, Australian Centre for International Agricultural Research, Canberra 2001, pp. 105-117. More recently, later authors have argued that these sandplains are mostly the product of in situ weathering. The carbonate material of all three dune systems has been completely leached, leaving dunes which consist solely of quartz sand. Within the Spearwood dunes, the yellow or grey sand may be several metres thick. The dune systems have been much studied, as the water retained within them supplies much of Perth's water needs. (See

Gnangara Mound The Gnangara Mound is an area north of Perth, Western Australia where a large mound of sandy soil reaches an elevation of about . It stores about of fresh water, about one hundred times Perth's current annual water usage. It is currently the si ...

Climate

In the southwest of Australia, the Nyoongar seasonal calendar includes six different seasons in a yearly cycle. These are Birak, Bunuru, Djeran, Makuru, Djilba and Kambarang. Each of the six seasons represents and explains the seasonal changes we see annually. The flowering of many different plants, the hibernation of reptiles and the moulting of swans are all helpful indicators that the seasons are changing. The Nyoongar seasons can be long or short and are indicated by what is happening and changing around us rather than by dates on a calendar. Aligning Nyoongar seasons with Western calendar months can provide an overview of a typical year. This six season calendar is extremely important to Nyoongar people, as it is a guide to what nature is doing at every stage of the year, as well as understanding respect for the land in relation to plant and animal fertility cycles and land and animal preservation. The south west region of Western Australia was one of the first places on earth to experience the effects of human induced climate change, namely a significant decline in annual rainfall. The drying climate is expected to continue and exacerbate bushfires. The summer of 2021/22 has been the hottest on record, with many consecutive days over 40 degrees Celsius.

Ecology

The Swan Coastal Plain is a specific botanical province.Paczkowska, Graznya and Chapman. Alex R. ''The Western Australian flora: a descriptive catalogue'' Wildflower Society of Western Australia, Western Australian Herbarium, CALM, and the Botanic Gardens & Parks Authority, Perth. 2000.

Flora

Southwestern Australia is very rich in flora, with an estimated 8,000 species, a quarter of which can be found on this coastal strip. The traditional flora of the dunes and the fairly infertile plain was dense shrubby

kwongan Kwongan is plant community found in south-western Western Australia. The name is a Bibbelmun (Noongar) Aboriginal term of wide geographical use defined by Beard (1976) as Kwongan has replaced other terms applied by European botanists such as ...

heathland adapted to the poor soils, dry summers, and regular fires. Kwongan vegetation contains a large number of endemic plant species, especially shrubs and wildflowers, including yellow flame and toothbrush grevilleas, fan-flowers, and cockies' tongues. The heath is scattered with woodland of ''

Banksia ''Banksia'' is a genus of around 170 species in the plant family Proteaceae. These Australian wildflowers and popular garden plants are easily recognised by their characteristic flower spikes, and fruiting "cones" and heads. ''Banksias'' range ...

'' and other trees including the red-blossomed

quandong Quandong, quandang or quondong, is a common name for the species '' Santalum acuminatum'' (desert, sweet, Western quandong), especially its edible fruit, but may also refer to * '' Aceratium concinnum'' (highroot quandong) * '' Peripentadenia mea ...

(desert peach) and firewood banksia. Going further inland, especially in river valleys where the soil is better,

eucalyptus ''Eucalyptus'' () is a genus of over seven hundred species of flowering trees, shrubs or mallees in the myrtle family, Myrtaceae. Along with several other genera in the tribe Eucalypteae, including '' Corymbia'', they are commonly known as euca ...

woodlands including tuart ''(

Eucalyptus gomphocephala ''Eucalyptus gomphocephala'', known as tuart, is a species of tree, one of the six forest giants of Southwest Australia. Tuart forest was common on the Swan coastal plain, until the valuable trees were felled for export and displaced by the urb ...

)'' occur. The wetlands meanwhile have been particularly important ecologically, supporting a rich habitat of many plant varieties. The Swan Coastal Plain is a particularly important centre for certain types of plants, including ''Banksia'', but also '' Caladenia'' orchids and '' Leucopogon'' shrubs, indeed some genera, such as the ''

Dryandra ''Banksia'' ser. ''Dryandra'' is a series of 94 species of shrub to small tree in the plant genus ''Banksia''. It was considered a separate genus named ''Dryandra'' until early 2007, when it was merged into ''Banksia'' on the basis of extensiv ...

'' series of ''Banksia'' and the '' Synaphea'' flowers are found nowhere else in the world. Other flora of the plain includes a type of mistletoe called the

Christmas tree A Christmas tree is a decorated tree, usually an evergreen conifer, such as a spruce, pine or fir, or an artificial tree of similar appearance, associated with the celebration of Christmas. The custom was further developed in early modern ...

Fauna

The coastal plains are home to a number of marsupials from the large

western grey kangaroo The western grey kangaroo (''Macropus fuliginosus''), also referred to as a western grey giant kangaroo, black-faced kangaroo, mallee kangaroo, sooty kangaroo and (when referring to the Kangaroo Island subspecies) Kangaroo Island grey kangaroo, is ...

to the very small

southwestern pygmy possum The western pygmy possum (''Cercartetus concinnus''), also known as the southwestern pygmy possum or the ''mundarda'', is a small marsupial found in Australia. Genetic studies indicate its closest relative is probably the eastern pygmy possum, ...

and mouse-like

honey possum The honey possum or noolbenger (''Tarsipes rostratus''), is a tiny species of marsupial that feeds on the nectar and pollen of a diverse range of flowering plants. Found in southwest Australia, it is an important pollinator for such plants as '' ...

. Remnant populations of some marsupials are found on offshore islands including the

Tammar wallaby The tammar wallaby (''Notamacropus eugenii''), also known as the dama wallaby or darma wallaby, is a small macropod native to South and Western Australia. Though its geographical range has been severely reduced since European colonisation, the ...

and the

quokka The quokka (''Setonix brachyurus'', ) is a small macropod about the size of a domestic cat. It is the only member of the genus ''Setonix''. Like other marsupials in the macropod family (such as kangaroos and wallabies), the quokka is herbivo ...

, the latter particularly on

Rottnest Island Rottnest Island ( nys, Wadjemup), often colloquially referred to as "Rotto", is a island off the coast of Western Australia, located west of Fremantle. A sandy, low-lying island formed on a base of aeolianite limestone, Rottnest is an A-class ...

. The coastal plains skink, discovered in 2012, is endemic to sand dunes in the area, and is threatened by residential development.

Threats and preservation

Much of the plain has been cleared for agriculture and urban development, especially in and around Perth, where the heath has been almost entirely cleared as far as the Darling Scarp and the city is spreading up and down the coast. Although some areas are protected, clearance is going on while the plant disease ''

Phytophthora ''Phytophthora'' (from Greek (''phytón''), "plant" and (), "destruction"; "the plant-destroyer") is a genus of plant-damaging oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, a ...

'' dieback and changes to traditional

fire regime A fire regime is the pattern, frequency, and intensity of the bushfires and wildfires that prevail in an area over long periods of time. It is an integral part of fire ecology, and renewal for certain types of ecosystems. A fire regime describes th ...

ns affect the heathland vegetation including the ''Banksia'' trees. Protected areas include Kings Park,

Beeliar Wetlands The Beeliar Wetlands is a wetland located in the southwest portion of Western Australia. It is made up of two chains of lakes and wetlands that run parallel to the west coast of Australia. They are situated on the Swan Coastal Plain between t ...

, Star Swamp, Hepburn Heights Bushland,

Canning River Regional Park The Canning River Regional Park is the largest of eight regional parks within the Perth metropolitan area. The park covers approximately on both sides of the Canning River between the bridges carrying Nicholson Road and Leach Highway over the ...

Bold Park Bold Park is a urban bushland area in the suburb of City Beach, in Perth, Western Australia. It is located directly west of the Perth central business district, its western border less than one kilometre from the Indian Ocean. To the east, ...

Whiteman Park Whiteman Park is a bushland area located north of Perth, Western Australia. The park is in the suburb of Whiteman, in the Swan Valley in the upper reaches of the Swan River. It encompasses the source of Bennett Brook - an important place o ...

, Kensington Bushland and

Thomsons Lake Thomsons Lake Nature Reserve is a lake nature reserve around Thomsons Lake (Noongar: ''Jilbup'') in the City of Cockburn, Western Australia, approximately south of the central business district of Perth, the state capital, and on the southern ...

History

Traditionally, this area was under the care and control of the Yued,

Whadjuk Whadjuk, alternatively Witjari, are Noongar (Aboriginal Australian) people of the Western Australian region of the Perth bioregion of the Swan Coastal Plain. Name The ethnonym appears to derive from ''whad'', the Whadjuk word for "no". Countr ...

Binjareb The Bindjareb, Binjareb, Pindjarup or Pinjareb are an Indigenous Noongar people that occupy part of the South West of Western Australia. Name It is not clear if ''Pindjarup'' is the historically correct ethnonym for the tribe. After their d ...

, and Wardandi

Noongar The Noongar (, also spelt Noongah, Nyungar , Nyoongar, Nyoongah, Nyungah, Nyugah, and Yunga ) are Aboriginal Australian peoples who live in the south-west corner of Western Australia, from Geraldton on the west coast to Esperance on the so ...

peoples, whose hunter-gathering

firestick farming Fire-stick farming, also known as cultural burning and cool burning, is the practice of Aboriginal Australians regularly using fire to burn vegetation, which has been practised for thousands of years. There are a number of purposes for doing this ...

practices maintained the

climax vegetation In scientific ecology, climax community or climatic climax community is a historic term for a community of plants, animals, and fungi which, through the process of ecological succession in the development of vegetation in an area over time, hav ...

old growth forests An old-growth forestalso termed primary forest, virgin forest, late seral forest, primeval forest, or first-growth forestis a forest that has attained great age without significant disturbance, and thereby exhibits unique ecological featur ...

observed at the time of first contact. At this time, the kwongan heathland was much more widespread along the coast. In the 1830s, it was originally named Great Plain of Quartania or Plain of Quartania by James Stirling, the first governor of Western Australia, but those terms have fallen into disuse. European settlement led to many of the wetlands areas being drained for land reclamation to take advantage of the fertile soil for farming enterprises, and for expansion of parks and recreation areas. The city of Perth sits on an area of reclaimed wetlands. Between 49% (Riggert, 1966) and 80% (Godfrey, 1989) of the wetlands on the coastal plain is thought to have been drained, filled, or cleared since 1832.

Lake Monger Lake Monger ( nys, Keiermulu) is a large urban wetland on the Swan Coastal Plain in suburban Perth, Western Australia nestled between the suburbs of Leederville, Wembley and Glendalough. Located less than from the city of Perth and situated ...

and

Herdsman Lake Herdsman Lake ( nys, Njookenbooro), also known as Herdsmans Lake, is a freshwater lake located on the Swan Coastal Plain, north-west of Perth, Western Australia, in the suburb of Herdsman. The main shared use path around the lake is approxima ...

are the last two major wetlands remaining in close proximity to the city. Lake Monger was originally part of a series of freshwater wetlands running north from the Swan River along the coastal plain for about . Lake Monger with Georgiana Lake and Lake Sutherland (both near

Mitchell Freeway The Mitchell Freeway is a freeway in the northern suburbs of Perth, Western Australia, linking central Perth with the city of Joondalup. It is the northern section of State Route 2, which continues south as Kwinana Freeway and Forrest ...

, near Sutherland and Newcastle streets) and

made up what was known as "The Great Lakes District". Other lakes and swamps in the immediate northern vicinity of the early Perth township were Lake Kingsford (site of the current

Perth railway station Perth railway station is the largest station on the Transperth network, serving the central business district of Perth, Western Australia. It serves as an interchange between the Airport, Armadale, Fremantle, Joondalup, Mandurah and Midland ...

), Lake Irwin (

Perth Entertainment Centre The Perth Entertainment Centre was an indoor arena and cinema complex in Perth, Western Australia, located on Wellington Street at the northern edge of the Perth central business district. It was demolished as part of the Perth City Link projec ...

) and further north were Stone's Lake (Perth Oval), Lake Poullet (First Swamp, part of what is now Birdwood Square), Lake Thomson (Mews Swamp, between Lake, Brisbane, and Beaufort Streets) and Lake Henderson (parts of what is now Robertson Park and Dorrien Gardens). Further north still lay Second Swamp (Bulwer Street, east of Lake Street), Third Swamp (Hyde Park), and Three Island Lake and Smith's Lake (now Charles Veryard Reserve). Many of these lakes formed a natural interconnected drainage system which found its way into the Swan River at East Perth through Claise Brook. In 1833, water draining from Lakes Kingsford, Irwin, Sutherland, and Henderson was used to drive a water-driven mill located in Mill Street.

References

External links

* Maps: Australia's bioregions IBRA 5.1 * http://www.environment.gov.au/parks/nrs/science/bioregion-framework/ibra/index.html IBRA 6.1 Explorer * http://www.environment.gov.au/metadataexplorer/explorer.jsp
– an online version of Thackway and Cresswell
{{Physical geography topics IBRA regions Mediterranean forests, woodlands, and scrub in Australia Physiographic provinces Plains of Australia Southwest Australia