South Australia River Assessment
South Australia is Australia's third largest state covering an area of 984,000 km2. It has 3,700 km of coastline and comprises 12.8 percent of the total area of Australia. The state is approximately 1,201 km from east to west and approximately 1,139 km from north to south. It has a temperate climate, with hot and dry summers and brief rainy winters. South Australia is a land of generally low relief, the inland area being largely covered by featureless plains, or sand and gibber deserts. One of the more significant topographic features is the Mount Lofty-Flinders Ranges system extending north-south along the eastern half of the State. Kangaroo Island is the dominant island off the South Australian coastline. The River Murray enters the sea in South Australia and is the State's only major river.
The biological assessment of South Australian rivers showed that over 80% of the river length assessed was in reference condition; most of the rest significantly impaired signifying that 20-50 percent of the animal types have been lost. The environmental assessment found that around 96% of the assessed river length was modified, with 72% moderately and 26% substantially. This degradation was attributed to catchment disturbance, changes to the hydrological regime and to water quality.
Ninety five percent of the river length assessed had disturbed catchments, the majority of this in fair condition with degradation attributable to land use activities. Disturbance from infrastructure was a relatively minor contributor to the overall catchment disturbance. Twelve percent of the river length able to be assessed for hydrological disturbance showed change, with a third of this length in very poor condition as a result of severe changes to the mean annual flow and duration of flow. Only 36% of the total river length had sufficient hydrological data to enable disturbance to be assessed.
Riverine physical habitat has been altered in 83% of the river length assessed in South Australia. Modified connectivity (96% modified) contributed the most to altered physical habitat followed by changes in riparian vegetation (85% modified). Around 62% of the river length assessed was had severely modified riparian vegetation indicating that there is very little riparian vegetation left along these stretches of river.
Over 95% of the river length assessed in South Australia had altered water quality with elevated loads of suspended solids, total phosphorus and total nitrogen.
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.
- A key point of contact for river management in South Australia is the Environment Protection Agency. More information on South Australia's water quality management program can be found at http://www.environment.sa.gov.au/epa/water.html. The Department for Water Resources
- (www.dwr.sa.gov.au) are responsible for water resource and catchment management activities.
- 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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