Rivers - Assessment of River Condition - Australian National Territory
Australian National Territory River Assessment
Assessment Results
The Australian Capital Territory is approximately 80 km from north to south and 30km from east to west. The plains and hills of the north, where Canberra lies, rise to rugged ranges in the south and west of the Territory. The Murrumbidgee River flows through the Territory from the south-east to the north-west. Namadgi National Park in the south covers 40 percent of the Australian Capital Territory and adjoins Kosciusko National Park. The climate of the inland area of the Australian Capital Territory is a continental one with hot summers and cold, sunny winters.
The biological assessment of Australian Capital Territory rivers showed that 64% 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 84% of the assessed river length was below reference; 71% moderately and 13% substantially modified. Changes to hydrological regime and water quality contribute principally to this damage.
Approximately 60% of the river length assessed had undisturbed catchments. All of the river length able to be assessed for hydrological disturbance showed moderate change.
Around 45% of the river length assessed was affected by changes to the physical habitat, largely due to loss of riparian vegetation and changes to connectivity. Less than 5% of the river length assessed had water quality that was assessed as unmodified, with elevated loads of suspended solids, total phosphorus and total nitrogen in a majority of the river length assessed.
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
- The point of contact for river management in the Australian Capital Territory is Environment ACT. Information on water resources management, water quality, catchment management, and Waterwatch can be found at http://www.environment.act.gov.au/ie4/airandwater/water.html
- 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.