The Preston River is a river in the South West region of Western Australia

Western Australia

Western Australia is a state of Australia, occupying the entire western third of the Australian continent. It is bounded by the Indian Ocean to the north and west, the Great Australian Bight and Indian Ocean to the south, the Northern Territory to the north-east and South Australia to the south-east...

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The river has a total length of 84 kilometres (52 mi) and rises near Goonac siding then flows in a North Westerly direction until discharging into the Leschenault Estuary

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...

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The headwaters are located 80 kilometres (50 mi) inland within the Darling Range and run across the Blackwood Plateau and the Swan Coastal Plain

Swan Coastal Plain

The Swan Coastal Plain in Western Australia is the geographic feature which contains the Swan River as it travels west to the Indian Ocean. The coastal plain continues well beyond the boundaries of the Swan River and its tributaries, as a geological and biological zone, one of Western Australia's...

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The majority of the river catchment has been cleared for agriculture although some remnant forest vegetation exists at the headwaters.

The towns of Donnybrook

Donnybrook, Western Australia

-Tourism:Donnybrook has many town icons bearing the apple. On the main street, apple-shaped lights line the entrance of the Old Railway Station. These lights have recently been restored. Atop the east Donnybrook hill is a high tower with an apple at the top...

 and Boyanup

Boyanup, Western Australia

Boyanup is a town located on the South Western Highway in the South West agricultural region, 195 km south of Perth and 18 km south-east of Bunbury, Western Australia....

 are located on the shores of the Preston River.

The major tributaries

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the river include the Ferguson River

Ferguson River (Western Australia)

Ferguson River is a river in the South West region of Western Australia.The river has a total length of and rises in the Darling Range below Wellington Mill then flows in a north westerly direction until discharging into the Preston River at Picton near Bunbury. The only tributary of the river is...

 and Joshua Creek. Minor tributaries include Thomson Brook, Crooked Brook, Charley Creek, Waterfall Gully, Mininup Brook, Millbrook and Gavin Guly. The Glen Mervyn Dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 is located along the Preston River.

The river basin is monitored routinely as a result of eutrophication

Eutrophication

Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...

 problems within the Leschenault Inlet. The water quality is fresh in many places and generally low in nutrients although some areas are slightly enriched with nitrogen

Nitrogen

Nitrogen is a chemical element that has the symbol N, atomic number of 7 and atomic mass 14.00674 u. Elemental nitrogen is a colorless, odorless, tasteless, and mostly inert diatomic gas at standard conditions, constituting 78.08% by volume of Earth's atmosphere...

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