Leschenault Estuary is an estuarine lagoon that lies to the north of

Bunbury, Western Australia Bunbury is a coastal city in the Australian state of Western Australia, approximately south of the state capital, Perth. It is the state's third most populous city after Perth and Mandurah, with a population of approximately 75,000. Located a ...

. It had in the past met 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 t ...

at the Leschenault Inlet, but that has been altered by harbour works for Bunbury, and the creation of The Cut north of the historical inlet location. The estuary is approximately in length and has a maximum width of approximately . The total area of the estuary is The lagoon is separated from the ocean by a thin peninsula of sand dunes called the Leschenault Peninsula.

Catchment

The catchment area below Wellington Dam for the estuary covers . The catchment includes part of the Swan Coastal Plain, 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 ...

and the Darling Plateau. The

Collie Collies form a distinctive type of herding dogs, including many related landraces and standardized breeds. The type originated in Scotland and Northern England. Collies are medium-sized, fairly lightly-built dogs, with pointed snouts. Man ...

and

Preston River The Preston River is a river in the South West region of Western Australia. The river has a total length of and rises near Goonac siding then flows in a north-westerly direction until discharging into the Leschenault Estuary. The headwaters ...

s are the main catchment rivers and enter the estuary from the southern end and with the catchment runoff discharging into 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 t ...

via the cut in the peninsula. Other rivers in the catchment area include the Brunswick River, Ferguson and Wellesley as well as numerous other creeks, streams and irrigation drains. Seven local government areas are located within the catchment including Bunbury,

, Capel,

Dardanup Dardanup is a small town in the South West (Western Australia), South West region of Western Australia. The town is in the fertile Ferguson valley and is near the Ferguson River (Western Australia), Ferguson River. The first European settlemen ...

Harvey Harvey, Harveys or Harvey's may refer to: Arts, entertainment, and media * ''Harvey'' (play), a 1944 play by Mary Chase about a man befriended by an invisible anthropomorphic rabbit * Harvey Awards ("Harveys"), one of the most important awards ...

, Donnybrook-Balingup and Boyup Brook. The catchment has a total population of approximately 65,000 people. The catchment area retains 40% of its natural

vegetation Vegetation is an assemblage of plant species and the ground cover they provide. It is a general term, without specific reference to particular taxa, life forms, structure, spatial extent, or any other specific botanical or geographic characte ...

, the remainder of the area has been cleared mostly for agricultural purposes with some light industry.

History

The sand dune system responsible for the formation of the estuary began about 7,000 years ago. At this time the coast section between

Mandurah Mandurah () is a coastal city in the Australian state of Western Australia, situated approximately south of the state capital, Perth. It is the state's second most populous city, with a population of 107,641 as of the 2021 census. Mandurah's ...

and Bunbury was an open rocky

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

shore. A dune system began to build on the shore forming a long barred estuarine lagoon between the current estuary as far north as Lake Preston and effectively separated the lagoon from the ocean. About 4,500 years ago the dune system met up with the eastern shore of the estuary separating the lagoon into two sections. The northern portion filled with mud leaving the southern section as the estuary that exists today. Construction of The Cut, a channel that opens the estuary into the ocean opposite the Collie River mouth, commenced in February 1950. Two explosive packages were found in the inlet in 2013. The first package composed of tri-cyclic acetone peroxide was found near a jetty and taken to Gloucester Park in

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 i ...

to be detonated in a controlled explosion. Divers searched the surrounding area the following day and found another package of the same explosive that was detonated on site. Traffic along the Old Coast Road was disrupted as a result.

Flora and fauna

A white mangrove colony exists within the estuary. These are the most southern mangroves in Western Australia and are believed to be 2,500 years old. The mangroves inhabit an area of . A boardwalk with informative signage has been constructed around the Mangrove colony so that visitors can inspect the area.

Waterbird A water bird, alternatively waterbird or aquatic bird, is a bird that lives on or around water. In some definitions, the term ''water bird'' is especially applied to birds in freshwater ecosystems, although others make no distinction from seabi ...

s depend on the area for habitat. Up to 62 species of waterbird use the estuary, mostly feeding in the tidal salt-marshes. The estuary is also an important fish nursery area.

Catchment

History

Flora and fauna

See also

References

Further reading