Victoria River Assessment
Victoria covers an area of 227,600 km2, has 1,800 km of coastline, and is 2.6 percent of the total area of Australia. The climate is strongly affected by the Great Dividing Range, running east west across the State, and rising to nearly 2,000 metres in the eastern half. This range acts as a barrier to the moist south-east and south-west winds and, together with its proximity to the coast, causes the south of the State to receive more rain than the north. The lower rainfall to the north of the Great Divide is coupled with high temperatures during the summer.
The biological assessment of Victoria rivers showed that approximately 77% of the river length assessed was in reference condition; most of the rest significantly impaired with 20-50 percent of the animal types have been lost. The environmental assessment found that around 80% of the assessed river length was modified; 59% moderately and 20% substantially. This degradation was attributed to catchment disturbance, changes to the hydrological regime and to water quality.
Approximately 90% of the river length assessed had disturbed catchments, the majority of this attributable to land use activities. Over 40% of the river length able to be assessed for hydrological disturbance showed change, with 16% substantially or severely modified. Most of the four flow regime measures showed change.
Riverine physical habitat has been altered in approximately 50% of the river length assessed in Victoria as a result of changes to connectivity, riparian vegetation and bedload condition. Over 60% of river length assessed had substantially or severely modified riparian vegetation, indicating that there is very little riparian vegetation left along these sections of river.
Around 70% of the river length assessed in Victoria had altered water quality with elevated loads of suspended solids (65% river length assessed) and total phosphorus (65%).
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 Victoria is the Department of Natural Resources and Environment. Information on Victoria's Environmental Flow Program can be found at http://www.nre.vic.gov.au/web/root/domino/cm_da/nrenlwm.nsf/frameset/NRE+Land+and+Water?OpenDocument and Catchment Management Authorities at http://www.nre.vic.gov.au/web/root/domino/cm_da/nrenlwm.nsf/frameset/NRE+Land+and+Water?OpenDocument. For more information about the study of the environmental condition of rivers in Victoria called the Index of Stream Condition go to www.vicwaterdata.net/isc/
- 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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