Rivers - Assessment of River Condition - New South Wales
New South Wales River Assessment
Assessment Results
New South Wales covers an area of 801,600 km2, has 1,900 km of coastline and comprises 10.4 percent of the area of Australia. It is the most populous. The climate varies with the landscape; sub-tropical along the north coast, temperate on the south coast, hot, dry summers in the north-west, and cold, sharp winters in the high country. The State can be divided into four natural regions; the fertile coastal region, the high tablelands and peaks of the Great Dividing Range, the pastoral and farming country of the Range's western slopes, and the plains that stretch westward to the South Australian border.
The biological assessment of New South Wales rivers showed that 51% of the river length assessed was in reference condition; with 13% of the river length as severely impaired signifying that 50-80 percent of the animal types have been lost. The environmental assessment found that 97% of the assessed river length was degraded; 68% moderately, and 30% substantially.
90 percent of the river length assessed had some degree of catchment disturbance, with the vast majority of rivers classified as moderately modified. The effects were attributable mainly to land use effects. Catchment disturbance caused by infrastructure (roads, rail) and land clearing were minor overall though significant in localised areas. Approximately 60% of the river length able to be assessed for hydrological disturbance showed change, with 47% of reaches moderately modified. Only 21% of the total river length in New South Wales was able to be assessed due to the lack of suitable data.
More than 70% of the river length assessed was affected by changes to the physical habitat, largely due to loss of riparian vegetation and changes to the bedload condition. Only 3% of the river length assessed had water quality that was assessed as in reference condition. Over 84% of the river length assessed had elevated loads of suspended solids, and 95% with elevated total phosphorus loads.
Comparison of the Biota Index and the Environment Index
Ideally, scores for the two main indices would be similar for each basin. In general, the Biota Index does not demonstrate the same degree of degradation as the Environment Index. Reasons for this may include:
- macroinvertebrates may be insensitive to some environmental changes, including large-scale changes (e.g. changes in connectivity and catchment disturbance), and to changes in some riverine habitat components (e.g. changes in salinity). Other biota, such as streamside and aquatic plants, algae, fish or water birds, in addition to invertebrates would give a more comprehensive assessment of the cumulative effects of environmental change.
- there may be lags between environmental degradation and biotic condition (e.g. nutrient or sediment loads to streams); or
- an environmental component that would explain a biotic response was not measured (e.g. a toxicant).
Environment Index scores compared to Biota Index scores for all basins.
Further Information
- A key point of contact for river management in New South Wales is the Department of Land and Water Conservation. More information on water management in New South Wales can be found at www.dlwc.nsw.gov.au/care/water/index.html
- Data and information on daily river heights, river flows and some salinity data at over 500 river monitoring sites on inland rives can be found at www.waterinfo.dlwc.nsw.gov.au. This site includes storage levels in major irrigation dams across New South Wales and water level data at coastal monitoring stations operated on behalf of Department of Land and Water Conservation by Manly Hydraulics Laboratory.
- Exit to more information on the AUSRIVAS for an introduction, models, taxonomy and downloads.
- Assessment of River Condition: and audit of the ecological condition of Australian rivers (by R. Norris, I. Prosser, B. Young, P. Liston, N. Bauer, N. Davies, F. Dyer, S. Linke, and M. Thoms)(PDF 4418 KB)
- View the Audit's Australian Catchment, River and Estuary Assessment 2002
- View the Audit's Australian Agriculture Assessment 2001
- Link to Data Library to download data and metadata
- Link to the Map Maker to make a map using this information.
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