Leschenault Estuary
Leschenault Estuary is an estuarine lagoon that lies to the north of Bunbury, Western Australia. It had in the past met the Indian Ocean 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 13.5 km (8.4 mi) in length and has a maximum width of approximately 2.5 km (1.6 mi). The total area of the estuary is 25 km2 (9.7 sq mi) The lagoon is separated from the ocean by a thin peninsula of sand dunes called the Leschenault Peninsula.
The catchment area below Wellington Dam for the estuary covers 1,981 km2 (765 sq mi). The catchment includes part of the Swan Coastal Plain, the Darling Scarp and the Darling Plateau.
The Collie and Preston Rivers are the main catchment rivers and enter the estuary from the southern end and with the catchment runoff discharging into the Indian ocean 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, Collie, Capel, Dardanup, Harvey, 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, the remainder of the area has been cleared mostly for agricultural purposes with some light industry.
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 and Bunbury was an open rocky limestone 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.
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