You are here: ANRA home » Natural resource topics » Coasts
This web site is no longer being updated
In this section you will find detailed information, including national overviews and state and regional level assessments, from the 2000-2002 National Land and Water Resources Audit theme assessments.
Australian Catchment, River and Estuary Assessment 2002
National Land and Water Resources Audit, 2002
ISBN 0 642 37125 3
Catchment condition
Photo: Jim Tait.
The poorest relative condition class catchments are in areas with intensive land use. They occur in cleared, agronomically marginal rainfall areas appearing as a crescent shape through inland Australia at the margins of the main cropping areas. These areas have soils of relatively poor fertility and structural properties. They are prone to soil structure decline, soil erosion and salinisation. They also have low flexibility in terms of land use options.
Other catchments in the relatively poor condition class have more reliable rainfall and greater land use flexibility. They have the potential for recovery given appropriate management.
Native vegetation changes and intensity of land use cause changes to the water cycle, soil chemistry and soil structure. They are the main drivers of catchment condition. Several indicators are highly representative of overall catchment biophysical condition and provide a minimum set for monitoring activities.
Composite catchment condition assessment (14 indicators)
5 km x 5 km grid cell scale
When viewed at the 5 x 5 km grid cell resolution (Figure 14), the relative biophysical condition of catchments within the assessment area shows a clear pattern of clusters of the grid cells into larger patches.
The most coherent and solid patches with relatively poorer condition occur in:
- the wheat-sheep belt and coastal agricultural areas of Western Australia;
- cropping areas of South Australia;
- western and central Victoria;
- the western slopes and plains of New South Wales; and
- the north-east Murray-Darling Basin in southern Queensland.
Disjunct areas of poorer catchment condition also occur in the larger inland-extending basins in central and south-eastern Queensland; and coastal floodplain areas of north, central and south-eastern Queensland and northern New South Wales. The more intensively developed central coastal basins of New South Wales also show poorer condition. In Tasmania the main patches of relatively poor condition match with the more intense cropping and grazing areas of the Tasmanian midlands.
The areas with relatively better condition correspond to conserved lands such as national parks, particularly in the non-tropical, higher rainfall areas. Other clusters of better condition are in the Northern Territory, Cape York and arid parts of western South Australia, corresponding with areas of lower land use intensity.
500 km² subcatchment scale
Aggregation to 500 km² subcatchment resolution shows a similar overall pattern (Figure 15) to the 5 x 5 km resolution but is limited in data variation spatially. There are large, coherent areas with relatively poorer conditions in the wheat and sheep zones of Western Australia, through western and central Victoria and west Gippsland, and onto the western slopes and plains of New South Wales.
In South Australia, Tasmania and Queensland the catchments in poorer condition appear confined and disjunct. In Queensland, these catchments in poorer condition include the upper reaches of the Condamine River in the Murray-Darling Basin, and the more intensively developed, larger river basins in central to south-east Queensland (Fitzroy, Burnett, Mary, Brisbane,) and smaller, coastal basins with developed, coastal floodplains.
Similar to the 5 x 5 km resolution, catchments in relatively good condition lie within the less intensively used parts of the assessment area. In the non-tropical higher rainfall zone, conserved lands have less influence and good condition areas are much more restricted. South-west Tasmania, north-eastern Victoria, the Blue Mountains National Park, parts of the upper Clarence River basin in New South Wales and the south-west of Western Australia are of relatively better catchment condition.
River basin scale
At the coarse level of aggregation to river basin scale (Figure 16), the poorest condition catchments occur in the Murray-Darling drainage division in south-eastern Queensland, western New South Wales and central northern Victoria. They include the Border Rivers, Namoi, Macquarie-Bogan Murrumbidgee, Murray-Riverina, Goulburn, Campaspe and Loddon River basins. River basins in the more intensively developed south-east of Queensland (Brisbane, Pine, Maroochy), central New South Wales coast (Sydney Coast - Georges River, Wollongong Coast) and central to western Victoria (Bunyip, Maribyrnong, Werribee, Moorabool, Barwon, Lake Corangamite and Hopkins) also fall into the poorest catchment condition class.
River basins in better condition are confined to the less intensively developed parts of the assessment area including, Cape York, the Northern Territory, arid rangelands in South Australia, southern Western Australia and the south-west of Tasmania.
Before you download
Most publications are downloadable as PDF files. Adobe Acrobat Reader is required to view PDF files.
If you are unable to access a publication, please contact us to organise a suitable alternative format.
Key
Links to an another web site
Opens a pop-up window