Water Quality and Aquatic Ecosystem Health

Picture of Lennox Street Bridge over Parramatta River with Jacaranda flowers on the ground

Water quality monitoring is carried out to provide information on the health of aquatic ecosystems and for recreational suitability. Monitoring programs can be single studies used to examine a particular issue or can be ongoing monitoring programs used to compare or highlight trends and changes in the range of parameters being measured. For water quality and aquatic ecosystem health monitoring, physical, chemical and biological information can be collected, analysed and interpreted in order to determine such change.

Currently there are two different monitoring programs carried out by Parramatta Council. The first program Water Quality Monitoring of the Upper Parramatta River Catchment has existed since 1990 when the Parramatta Advertiser commissioned a study of the water quality of the Upper Parramatta River Catchment. In 1991, the Upper Parramatta River Catchment Trust continued to fund the program until they disbanded in late 2006 when the Council stepped in to provide continued financial support for the sampling program. Under this program, 12 stations (including estuarine stations) are sampled monthly for a range of physical, chemical and biological parameters (25 water quality variables are sampled).

The second monitoring program undertaken by Council was a Macroinvertebrate Sampling Program carried out for two years in 2003 and 2004 at 21 different sites across Parramatta. Macroinvertebrates (or water bugs) are living organisms that are large enough to be seen with the naked eye and inhabit aquatic environments for part or all of their life cycles. They have been found to be useful indicators of freshwater aquatic ecosystem health as some macroinvertebrates are more tolerant to pollution than others.

In Parramatta, the SIGNAL (Stream Invertebrate Grade Number – Average Level) Index was used to determine the health of each waterway.  This method takes advantage of the fact that macroinvertebrates have different tolerances to pollution and gives a measure of the pollution level of a water body ranging from a ‘healthy habitat’ to a ‘severely polluted’ one.

City of Parramatta Council is currently investigating the best way forward with its Water Quality Monitoring Program so as to ensure that the data collected is able to be used effectively, not only to monitor long term trends but to ensure the effectiveness of waterway improvement strategies.