Greenough River
Encyclopedia
The Greenough River is a river
in the Mid West region of Western Australia
.
at Cape Burney, about 9 kilometres (6 mi) south of Geraldton, Western Australia
.
The ten tributaries
that contribute to the Greenough are Woojalong Brook, Woolbarka Brook, Bangemall Creek, Urawa River, Kolanadgy Gully, Nangerwalla Creek, Wooderarrung River, Wandin Creek, Kockatea Creek and Wicherina Brook.
The lower reaches of the Greenough are estuarine; how far upriver the estuary extends is not certain, but probably about 7 kilometres, to near Bootenal Springs. The river mouth is barred from the ocean by a sandbar that breaks only in periods of strong flow. Once open, it usually remains open for several months. The bar has now been reinforced with brushwood on the northern side, to force the bar to open only on the southern side, where the adjacent dune is more stable.
Evidence from wind gaps suggests that, thousands of years ago, the Greenough River turned to the north-west a few kilometres further from the coast than it does at present, at the present-day site of Walkaway
. It then ran along the inside of a limestone ridge, following what is now the path of the Geraldton–Dongara railway line,, to the vicinity of Rudds Gully. Both watercourses then flowed north to discharge into the Chapman River
. Later, Rudds Gully cut its own path to the ocean, and the Greenough River discharged into it; and later still, the Greenough cut its own path through the limestone ridge at Walkaway, thus forming its own course.
The well-documented strong winds at Greenough
have resulted in large mobile dune system both to the south and north of the Greenough River mouth. Both are gradually moving northwards, and it is estimated that the southern dune will reach the mouth of the Greenough around 2045, at which point the Greenough may well become even more prone to flooding, or be forced to change its course.
was abandoned.
The river water is eutrophic and sediment
-laden, and there is evidence that this has affected the ecology of the area, with migratory wading birds no longer visiting the flood-plain in numbers as large as previously.
River
A river is a natural watercourse, usually freshwater, flowing towards an ocean, a lake, a sea, or another river. In a few cases, a river simply flows into the ground or dries up completely before reaching another body of water. Small rivers may also be called by several other names, including...
in the Mid 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...
.
Course
Nominally located at 28°51′S 114°38′E, Greenough River has its headwaters near Woojalong Hills on the Yilgarn Plateau. It runs in a south westerly direction through deep valleys for approximately 340 kilometres (211 mi), passing through the Waterloo Ranges before descending to the coastal plain. A few kilometres from the sea it is obstructed by dunes, and turns to the north-west, running along a dune swale parallel with the coast for about 35 kilometres before finally discharging into the Indian OceanIndian Ocean
The Indian Ocean is the third largest of the world's oceanic divisions, covering approximately 20% of the water on the Earth's surface. It is bounded on the north by the Indian Subcontinent and Arabian Peninsula ; on the west by eastern Africa; on the east by Indochina, the Sunda Islands, and...
at Cape Burney, about 9 kilometres (6 mi) south of Geraldton, Western Australia
Geraldton, Western Australia
Geraldton is a city and port in Western Australia located north of Perth in the Mid West region. Geraldton has an estimated population at June 2010 of 36,958...
.
The ten 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...
that contribute to the Greenough are Woojalong Brook, Woolbarka Brook, Bangemall Creek, Urawa River, Kolanadgy Gully, Nangerwalla Creek, Wooderarrung River, Wandin Creek, Kockatea Creek and Wicherina Brook.
The lower reaches of the Greenough are estuarine; how far upriver the estuary extends is not certain, but probably about 7 kilometres, to near Bootenal Springs. The river mouth is barred from the ocean by a sandbar that breaks only in periods of strong flow. Once open, it usually remains open for several months. The bar has now been reinforced with brushwood on the northern side, to force the bar to open only on the southern side, where the adjacent dune is more stable.
Evidence from wind gaps suggests that, thousands of years ago, the Greenough River turned to the north-west a few kilometres further from the coast than it does at present, at the present-day site of Walkaway
Walkaway, Western Australia
Walkaway is a small town in the City of Greater Geraldton local government area of Western Australia. At the 2006 census, Walkaway had a population of 262....
. It then ran along the inside of a limestone ridge, following what is now the path of the Geraldton–Dongara railway line,, to the vicinity of Rudds Gully. Both watercourses then flowed north to discharge into the Chapman River
Chapman River (Western Australia)
Chapman River is a river in the Mid West region of Western Australia.-Course:The river arises on the Victoria Plateau east of Northampton. It flows in a southerly direction, passing through the town of Nabawa in the Shire of Chapman Valley, and continuing south to about the latitude of Geraldton...
. Later, Rudds Gully cut its own path to the ocean, and the Greenough River discharged into it; and later still, the Greenough cut its own path through the limestone ridge at Walkaway, thus forming its own course.
The well-documented strong winds at Greenough
Greenough
Greenough may refer to:* Greenough, Western Australia, a historic town* Greenough River, a river in Western Australia* Shire of Greenough, a former local government area in Western Australia...
have resulted in large mobile dune system both to the south and north of the Greenough River mouth. Both are gradually moving northwards, and it is estimated that the southern dune will reach the mouth of the Greenough around 2045, at which point the Greenough may well become even more prone to flooding, or be forced to change its course.
Hydrology
The river is dry most of the time, but has a number of permanent pools such as Bootenal Spring. However the entire basin is prone to severe flooding which have periodically devastated local farming communities. The worst on record occurred in 1888: over 50 square kilometres was flooded; the water was over 5 metres deep south of Greenough; four people were drowned and many financially ruined; and ultimately the town of GreenoughGreenough, Western Australia
Greenough is a historical town located 400 kilometres north of Perth, Western Australia and 24 kilometres south of Geraldton on the Brand Highway. The historic buildings are controlled by the National Trust of Australia...
was abandoned.
The river water is eutrophic and sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
-laden, and there is evidence that this has affected the ecology of the area, with migratory wading birds no longer visiting the flood-plain in numbers as large as previously.