Sixth Creek

Water quality links:

Home

What is water quality?

Direct to data

Monitoring program & assessments

Major threats & issues

Legislation & programs

Other resources & initiatives

Publications

Glossary

Introduction

Sixth Creek is a freshwater stream in the Mount Lofty Ranges. It flows north to meet the Torrens River at Castambul. The catchment is a mixture of rural residential, horticulture, orchards and grazing land. Elevated turbidity and nutrient levels are the most likely water quality problems.

The site is on the lower reaches of the catchment just upstream of the confluence with the Torrens River. It includes approximately 46 km² of catchment. The site is on a cobbled stretch of the creek bordered by relatively dense trees and aquatic plants. Stream flow for this site is available from the Department of Water, Land and Biodiversity Conservation. >> Map (3MB PDF)

Water quality assessment

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

Ecological health is assessed in spring and autumn using the AUSRIVAS model. We use macroinvertebrates for this purpose because they provide a relatively simple way to assess the health of an aquatic ecosystem. >> More

Water chemistry is measured each month. We measure chemical indicators because when they reach a certain level they can cause stress or toxicity to animals and plants in an ecosystem. Some indicators can also indicate if the water is suitable for drinking water or for activities such as swimming. >> More

Ecological health

We collect two samples of macroinvertebrates, one from riffle (or flowing water) habitat and one from edge (still water) habitat. The diversity of the macroinvertebrate community is used to describe ecological health as being in good, moderate or poor condition.

Go here to find out how we classify ecological health in streams.

Ecological health assessment for May 2006

Habitat	Ecological health
Edge	Good
Riffle	Good

Both the edge and riffle habitats are usually rated in good condition at this site, but in autumn 2006 the riffle was in a slightly impaired (moderate) condition. This may be a result of the low flows associated with the drought.

The edge habitat had a high species richness of 41 different types of macroinvertebrates. The most common were hypogastrurid springtails, baetid mayflies that included Offadens species and the caenid mayfly Tasmanocoenis tillyardi. The riffle habitat was also diverse with 36 types of macroinvertebrates. The most common were gripopterygid stoneflies, baetid mayflies, blackfly larvae and the caddisfly Lingora aurata.

The site lacked any amphipods, dytiscid and hydrophilid beetles, and odonates when sampled in May 2006. The AUSRIVAS model indicated that the riffle was classified moderate, possibly based on the lack of these species However, the presence of such a diverse fauna that includes several mayflies, stoneflies and caddisflies, suggests that this site is really in a good condition, equivalent to other best condition sites in the State.

A number of rare macroinvertebrates were collected in autumn 2006, including the elmid beetle Simsonia leai, dipteran larvae from the family Empididae, and the caddisflies Lingora aurata and Taschorema evansi.

Download ecological health data

• All the macroinvertebrate data for Sixth Creek

Water chemistry

The indicators that are measured in Sixth Creek 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

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

The results in this monitoring period were generally consistent with previous results for this site, where the oxidised nitrogen levels are often elevated.

The oxidised nitrogen classification is poor which is probably due to fertilisers or animal wastes being washed into the creek during storms. The elevated oxidised nitrogen would normally lead to excessive algal growth, although the relatively dense reed beds in the creek and shading from riparian vegetation probably prevent this from occurring.

There are several projects and programs being run which are designed to improve water quality in Sixth Creek. These are being coordinated through the EPA's Watershed Protection Office and the Adelaide and Mt Lofty Ranges Natural Resources Management Board.

>> Archived results

Download water chemistry graphs

• Oxidised nitrogen in Sixth Creek
• Total nitrogen in Sixth Creek
• Total phosphorus in Sixth Creek
• Soluble phosphorus in Sixth Creek
• Turbidity in Sixth Creek
• Salinity in Sixth Creek

Download raw chemistry data

• All chemistry data for Sixth Creek

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