Willson River |
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Water quality links: Monitoring program & assessments << back to Kangaroo Island |
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| Habitat |
Ecological health
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| Edge |
Moderate
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| Riffle |
Moderate
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The edge and riffle habitats in the Willson River were rated in a moderate (slightly impaired) condition in autumn 2006, whereas in previous years the site was generally in good condition. The salinity of the stream was about 11,000 mg/L and may have contributed to the poorer overall condition of this Kangaroo Island waterway in autumn 2006.
The edge habitat had 27 different types of macroinvertebrates, with the most common species being amphipods Austrochiltonia australis, oligochaete worms and hydrobiid snails. The riffle only had 14 different macroinvertebrates with the same animals found near the edges. No flow dependant macroinvertebrates were collected at the site.
The site was considered impacted due to the absence of dytiscid
and hydrophilid beetles, mayflies, waterbugs and caddisflies.
The only interesting observation at the site was the colonial
cnidarian Cordylophora.
Download ecological health data
Water chemistry
The indicators that are measured in the Willson River are nutrients (nitrogen and phosphorus), turbidity and salinity. The concentrations of these indicators are used to classify the water chemistry as being in good, moderate or poor condition, according to the needs of aquatic ecosystem protection.
Go here to find out how we organise and classify the chemistry data.
Water chemistry classification for April to September 2006
The results in this monitoring period were generally consistent with previous results for this site, with relatively high nitrogen concentrations (both soluble and total). Highest concentrations seem to occur during the winter months, coinciding with higher river flows, although there are indications that the soluble nitrogen concentrations have been decreasing in recent years. The salinity also appears to have increased in recent years. Further monitoring is required to determine whether these observations are a trend in water quality.
The elevated nutrients in the Willson River are likely to be due runoff from grazing land or horticulture in the catchment (mainly fertilisers and animal wastes). Elevated nitrogen could lead to excessive algal growth, particularly during warmer months.
The Kangaroo Island NRM Board is preparing a water management plan that will include the Willson River. This plan will prioritise actions that should lead to water quality improvements.
Download water chemistry graphs
Download raw chemistry data
What is being done to improve the condition of South Australian rivers and streams
Efforts to improve the condition of South Australia's rivers and streams are being driven by various government agencies, primarily
The Environment Protection Authority
The Department of Water, Land and Biodiversity Conservation
Natural Resource Management Boards
Department for Environment and Heritage (SA)Collaborative projects and programs being run by these agencies are based on the protection of environmental values, as explained in the National Water Quality Management Strategy. >> More
This page was last modified 25-09-2007
