Chapman River (Western Australia)
Encyclopedia
Chapman River is a river in the Mid West region of Western Australia
.
. 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. It then descends to the coastal plain, turning to the west-northwest and disgorging into the Indian Ocean
at Bluff Point
in Champion Bay
. Tributaries
of the river include Chapman River East, Skelton Gully, Una Brook and Rushy Gully.
, phosphorus
and chlorophyll a
. This, together with the encroachment of urban areas into the river's riparian zone
, has resulted in a degraded river system with eutrophic lower reaches.
The river generally does not flow in summer, but always flows in winter. From the mouth to about 1.5 km upriver, the river is estuarine. This stretch always contains some water. The mouth itself is usually closed by a sandbar, but this opens at the onset of heavy flow, and closes after flow has receded. When the sandbar is open, sea water enters the estuary, mildly affecting its salinity.
During periods of very high rainfall, soils are washed into the river and carried out to sea. Following heavy rains in June and July 1986, it is estimated that: the Chapman River washed 39,000 tons of suspended sediment into the ocean; that at peak flow a ton of sediment entered the ocean every seven seconds; and that this loss of sediment represented the loss of some A$73,000 of soil nitrogen.
in 1839, and may have been named after John Chapman
, a British Conservative Member of Parliament
(MP) and then deputy chairman of the Western Australian Land Company.
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
The river arises on the Victoria Plateau east of NorthamptonNorthampton, Western Australia
Northampton is a town north of Geraldton, in the Mid West region of Western Australia. At the 2006 census, the town had a population of 813. It is historic, with an outstanding National Trust building. The town lies on the North West Coastal Highway. Formerly named Gwalla after the location's...
. It flows in a southerly direction, passing through the town of Nabawa
Nabawa, Western Australia
-External links:* Contains pictures of the town....
in the Shire of Chapman Valley
Shire of Chapman Valley
The Shire of Chapman Valley is a Local Government Area located in the Mid West region of Western Australia, immediately northeast of the city of Geraldton and about north of Perth, the state capital. The Shire covers an area of and its seat of government is the small town of Nabawa.-History:The...
, and continuing south to about the latitude of Geraldton. It then descends to the coastal plain, turning to the west-northwest and disgorging into the Indian Ocean
Indian 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 Bluff Point
Bluff Point, Western Australia
Bluff Point is a northern coastal suburb of Geraldton, Western Australia. Its Local Government Area is the City of Greater Geraldton.The suburb was gazetted in 1972.-Geography:...
in Champion Bay
Champion Bay
Champion Bay is a bay facing the port and the northern part of the city of Geraldton, Western Australia, between Point Moore and Bluff Point.Champion Bay was named by Captain Stokes of The Beagle who led an expedition to the area in December 1841...
. 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 Chapman River East, Skelton Gully, Una Brook and Rushy Gully.
Hydrology
Most of the Chapman River's 1,160 km² catchment consists of cleared agricultural land. This land is heavily fertilised and subject to soil erosion, so the river carries high concentrations of nitrogenNitrogen
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...
, phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...
and chlorophyll a
Chlorophyll a
Chlorophyll a is a specific form of chlorophyll used in oxygenic photosynthesis. It absorbs most energy from wavelengths of violet-blue and orange-red light. This photosynthetic pigment is essential for photosynthesis in eukaryotes, cyanobacteria and prochlorophytes because of its role as primary...
. This, together with the encroachment of urban areas into the river's riparian zone
Riparian zone
A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the fifteen terrestrial biomes of the earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by...
, has resulted in a degraded river system with eutrophic lower reaches.
The river generally does not flow in summer, but always flows in winter. From the mouth to about 1.5 km upriver, the river is estuarine. This stretch always contains some water. The mouth itself is usually closed by a sandbar, but this opens at the onset of heavy flow, and closes after flow has receded. When the sandbar is open, sea water enters the estuary, mildly affecting its salinity.
During periods of very high rainfall, soils are washed into the river and carried out to sea. Following heavy rains in June and July 1986, it is estimated that: the Chapman River washed 39,000 tons of suspended sediment into the ocean; that at peak flow a ton of sediment entered the ocean every seven seconds; and that this loss of sediment represented the loss of some A$73,000 of soil nitrogen.
Conservation
The Chapman River's riparian zone is now managed as part of the Chapman Regional Wildlife Corridor Project, and much of it is afforded some protection by the declaration of regional parks within the zone, Such as Spalding Park.History
It was discovered and named by George GreyGeorge Grey
George Grey may refer to:*Sir George Grey, 2nd Baronet , British politician*George Grey, 2nd Earl of Kent *Sir George Grey , Governor of Cape Colony, South Australia and New Zealand...
in 1839, and may have been named after John Chapman
John Chapman (1810–1877)
John Chapman DL, JP was a British Conservative Party politician who served for two three-year terms as the Member of Parliament for Great Grimsby....
, a British Conservative Member of Parliament
Member of Parliament
A Member of Parliament is a representative of the voters to a :parliament. In many countries with bicameral parliaments, the term applies specifically to members of the lower house, as upper houses often have a different title, such as senate, and thus also have different titles for its members,...
(MP) and then deputy chairman of the Western Australian Land Company.