| Chapman River [1] | |
|---|---|
 Bridge over the Chapman River, Geraldton, 1946 | |
| Location | |
| Country | Australia |
| Physical characteristics | |
| Source | |
| • location | Yuna |
| • elevation | 270 metres (886 ft) [2] |
| Mouth | |
• location | Bluff Point |
| Length | 105 kilometres (65 mi) |
| Basin size | 1,644 square kilometres (635 sq mi) [3] |
Chapman River is a river in the Mid West region of Western Australia.
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. It then descends to the coastal plain, turning to the west-north-west and disgorging into the Indian Ocean at Bluff Point in Champion Bay. [4] Tributaries of the river include Chapman River East, Skelton Gully, Una Brook and Rushy Gully.
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 nitrogen, 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. [4]
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. [4]
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.
The Chapman River's riparian zone is 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. [4]
The Chapman River was named on 7 April 1839 by the explorer George Grey while on his second disastrous expedition along the Western Australian coast, [5] and was probably named after John Chapman, later a British Conservative Member of Parliament (MP) but then deputy chairman of the Western Australian Company. [6] Chapman was a business partner of Grey's friend Sir William Hutt (Chairman of the Western Australian Company and brother of John Hutt, second Governor of Western Australia), after whom Grey had named the nearby Hutt River, two days previously. [7] [5] [8]
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone through lithification.
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world.
A wetland is a distinct ecosystem that is flooded by water, either permanently or seasonally. Flooding results in oxygen-free (anoxic) processes prevailing, especially in the soils. The primary factor that distinguishes wetlands from terrestrial land forms or water bodies is the characteristic vegetation of aquatic plants, adapted to the unique anoxic hydric soils. Wetlands are considered among the most biologically diverse of all ecosystems, serving as home to a wide range of plant and animal species. Methods for assessing wetland functions, wetland ecological health, and general wetland condition have been developed for many regions of the world. These methods have contributed to wetland conservation partly by raising public awareness of the functions some wetlands provide.
A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is dominated by dense stands of salt-tolerant plants such as herbs, grasses, or low shrubs. These plants are terrestrial in origin and are essential to the stability of the salt marsh in trapping and binding sediments. Salt marshes play a large role in the aquatic food web and the delivery of nutrients to coastal waters. They also support terrestrial animals and provide coastal protection.
In oceanography, geomorphology, and geoscience, a shoal is a natural submerged ridge, bank, or bar that consists of, or is covered by, sand or other unconsolidated material and rises from the bed of a body of water to near the surface. It often refers to those submerged ridges, banks, or bars that rise near enough to the surface of a body of water as to constitute a danger to navigation. Shoals are also known as sandbanks, sandbars, or gravelbars. Two or more shoals that are either separated by shared troughs or interconnected by past or present sedimentary and hydrographic processes are referred to as a shoal complex.
A gully is a landform created by running water, mass movement, or commonly a combination of both eroding sharply into soil or other relatively erodible material, typically on a hillside or in river floodplains or terraces. Gullies resemble large ditches or small valleys, but are metres to tens of metres in depth and width and are characterised by a distinct 'headscarp' or 'headwall' and progress by headward erosion. Gullies are commonly related to intermittent or ephemeral water flow usually associated with localised intense or protracted rainfall events, or snowmelt. Gullies can be formed and accelerated by cultivation practices on hillslopes in farmland, and they can develop rapidly in rangelands from existing natural erosion forms subject to vegetative cover removal and livestock activity.
Phosphorite, phosphate rock or rock phosphate is a non-detrital sedimentary rock that contains high amounts of phosphate minerals. The phosphate content of phosphorite (or grade of phosphate rock) varies greatly, from 4% to 20% phosphorus pentoxide (P2O5). Marketed phosphate rock is enriched ("beneficiated") to at least 28%, often more than 30% P2O5. This occurs through washing, screening, de-liming, magnetic separation or flotation. By comparison, the average phosphorus content of sedimentary rocks is less than 0.2%. The phosphate is present as fluorapatite Ca5(PO4)3F typically in cryptocrystalline masses (grain sizes < 1 μm) referred to as collophane-sedimentary apatite deposits of uncertain origin. It is also present as hydroxyapatite Ca5(PO4)3OH or Ca10(PO4)6(OH)2, which is often dissolved from vertebrate bones and teeth, whereas fluorapatite can originate from hydrothermal veins. Other sources also include chemically dissolved phosphate minerals from igneous and metamorphic rocks. Phosphorite deposits often occur in extensive layers, which cumulatively cover tens of thousands of square kilometres of the Earth's crust.
The Murchison River is the second longest river in Western Australia. It flows for about 820 km (510 mi) from the southern edge of the Robinson Ranges to the Indian Ocean at Kalbarri. The Murchison-Yalgar-Hope river system is the longest river system in Western Australia. It has a mean annual flow of 208 gigalitres, although in 2006, the peak year on record since 1967, flow was 1,806 gigalitres.
An aquatic ecosystem is an ecosystem in and surrounding a body of water, in contrast to land-based terrestrial ecosystems. Aquatic ecosystems contain communities of organisms that are dependent on each other and on their environment. The two main types of aquatic ecosystems are marine ecosystems and freshwater ecosystems. Freshwater ecosystems may be lentic ; lotic ; and wetlands.
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 terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks are called riparian vegetation, characterized by hydrophilic plants. Riparian zones are important in ecology, environmental resource management, and civil engineering because of their role in soil conservation, their habitat biodiversity, and the influence they have on fauna and aquatic ecosystems, including grasslands, woodlands, wetlands, or even non-vegetative areas. In some regions, the terms riparian woodland, riparian forest, riparian buffer zone,riparian corridor, and riparian strip are used to characterize a riparian zone. The word riparian is derived from Latin ripa, meaning "river bank".
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 Interim Biogeographic Regionalisation for Australia (IBRA) regions. It is also one of the distinct physiographic provinces of the larger West Australian Shield division.
Nonpoint source (NPS) pollution refers to diffuse contamination of water or air that does not originate from a single discrete source. This type of pollution is often the cumulative effect of small amounts of contaminants gathered from a large area. It is in contrast to point source pollution which results from a single source. Nonpoint source pollution generally results from land runoff, precipitation, atmospheric deposition, drainage, seepage, or hydrological modification where tracing pollution back to a single source is difficult. Nonpoint source water pollution affects a water body from sources such as polluted runoff from agricultural areas draining into a river, or wind-borne debris blowing out to sea. Nonpoint source air pollution affects air quality, from sources such as smokestacks or car tailpipes. Although these pollutants have originated from a point source, the long-range transport ability and multiple sources of the pollutant make it a nonpoint source of pollution; if the discharges were to occur to a body of water or into the atmosphere at a single location, the pollution would be single-point.
The Greenough River is a river in the Mid West region of Western Australia.
Hill River is a river in the Wheatbelt region of Western Australia.
The Fitzgerald River is a river in the Great Southern region of Western Australia.
Hutt River is a river in the Mid West region of Western Australia.
Hutt Lagoon is a marine salt lake located near the Indian Ocean coast 2 kilometres (1.2 mi) north of the mouth of the Hutt River, in the Mid West region of Western Australia.
The Bowes River is a river in the Mid West of Western Australia. It was named on 6 April 1839 by the explorer George Grey while on his second exploration expedition along the Western Australian coast. It was named for Mary Bowes, Dowager Countess of Strathmore, the wife of Sir William Hutt. Hutt was a British Liberal politician who was heavily involved in the colonization of New Zealand and South Australia, and the brother of John Hutt, the second governor of Western Australia. Sir William Hutt was a member of the 1836 select committee on Disposal of Lands in the British Colonies. Grey named the nearby Hutt River after Hutt.
The Buller River is a river in the Mid West of Western Australia, near Geraldton.
Legacy sediment (LS) is depositional bodies of sediment inherited from the increase of human activities since the Neolithic. These include a broad range of land use and land cover changes, such as agricultural clearance, lumbering and clearance of native vegetation, mining, road building, urbanization, as well as alterations brought to river systems in the form of dams and other engineering structures meant to control and regulate natural fluvial processes. The concept of LS is used in geomorphology, ecology, as well as in water quality and toxicological studies.
Coordinates: 28°43′43″S114°37′11″E / 28.72861°S 114.61972°E
Rivers of Western Australia | |
|---|---|
| Rivers of the Gascoyne region | |
| Rivers of the Goldfields-Esperance region | |
| Rivers of the Great Southern region | |
| Rivers of the Kimberley region |
|
| Rivers of the Mid West region | |
| Rivers of the Peel and Perth regions | |
| Rivers of the Pilbara region | |
| Rivers of the South West region | |
| Rivers of the Wheatbelt region | |
