Torrens Lake at the Weir

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Introduction

The monitoring site at Torrens Lake Weir is downstream of both urban and agricultural activities and therefore receives a large pollutant load. The site at Torrens Lake is only monitored from the perspective of recreational and aesthetic values. Another monitoring site on the Torrens River is at Mt Pleasant. First Creek and Sixth Creek are also monitored; these are tributaries of the Torrens River. >> Map (3MB PDF)

Water quality assessment

Water quality is assessed as being in good, moderate or poor condition by interpreting water chemistry data in the context of protecting environmental values. Water chemistry is measured each month. >> More

Water chemistry

The indicators that are measured in the Torrens Lake are turbidity and bacteria. 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 recreational environmental values.

Go here to find out how we organise and classify the chemistry data.

Water chemistry classification April to September 2006

Indicator	Classification
Oxidised Nitrogen	Poor
Total Nitrogen	Poor
Soluble Phosphorus	Good
Total Phosphorus	Good
Turbidity	Moderate
Bacteria	Moderate

The results in this monitoring period were generally consistent with previous seasonal results for this site.

The total nitrogen and oxidised nitrogen concentrations in the Torrens Lake are frequently elevated. This is not unexpected and is likely to be because of urban and peri-urban runoff from the Torrens catchment, which contains fertilisers, detergents and decaying natural organic matter (leaf litter). The total phosphorus concentration has also been elevated in the past for the same reason.

The nutrient concentrations do not directly affect the recreational values of the Torrens Lake. However, the high nutrient concentrations can lead to undesirable algal blooms, which can cause odours, appear unpleasant and may be toxic, resulting in closure of the lake.

The turbidity in the Torrens Lake was elevated in terms of its recreational (aesthetic) value. This would have been due to either algae and/or suspended sediment in the water. Elevated turbidity can make it difficult to see submerged obstacles, reducing the safety of some recreational activities. Many freshwater lakes in South Australia are naturally turbid (cloudy). Since the Torrens Lake also receives large volumes of stormwater, a high level of water clarity in the lake is difficult to achieve.

The bacterial (Enterococci) levels in Torrens Lake were also elevated for recreational uses (incidental contact during boating activities). Bacterial contamination is a common issue in urban stormwater.

The South Australian Department of Health has useful information on the safe use of recreational waters.

The Adelaide and Mount Lofty Ranges Natural Resources Management Board is responsible for managing water quality in the Torrens River catchment, while the Adelaide City Council is responsible for managing the aesthetic quality of the Torrens Lake between Hackney Road Bridge and the Torrens Weir.

>> Archived results

Download water chemistry graphs

• Oxidised nitrogen in Torrens Lake
  
• Total nitrogen in Torrens Lake
  
• Total phosphorus in Torrens Lake
  
• Soluble phosphorus in Torrens Lake)
  
• Turbidity in Torrens Lake
  
• Salinity in Torrens Lake
  
• Bacteria in Torrens Lake

Download raw chemistry data

• All chemistry data for Torrens Lake

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