ACT Water Report 1999-00

Executive Summary

TAMS undertakes a water monitoring program for the ACT that includes water quality and streamflow monitoring. This information is used to determine whether waters in the ACT are of adequate quality and if the management strategies used to achieve or maintain such water quality are appropriate.

This report provides the ACT community with the results of the 1999-2000 program and compares water quality indicator levels with the ACT Water Quality Standards.

Water quality is monitored in the major urban lakes (with the exception of Lake Burley Griffin, a Commonwealth responsibility) and Burrinjuck Reservoir which is immediately downstream of the ACT. The major rivers and some urban streams are also monitored. River flow is measured at a number of sites throughout the ACT.

Rainfall for the period was slightly above the long term average with higher rainfall during spring and lower rainfall throughout the rest of the year. Streamflow measured in the major streams and rivers was below the long term average, however higher flows associated with the higher spring rainfall had observable effects on water quality in some areas with elevated levels of turbidity at that time.

The report uses the median value for the year as the measure of the average condition. The condition of water quality at the monitoring sites is assessed by comparison of the median value with concentrations listed in the water quality standards for that particular indicator. For flow dependent indicators a flow concentration relationship has been used for comparison with the water quality standards.

Trend analysis of data available for the period 1992–2000 has been carried out for sites with sufficient data for trends to be analysed.

Lakes and streams in the ACT have generally good water quality. The main impacts on water quality in the urban area are a direct result of land development with urban run-off carrying suspended sediment and nutrients.

Lake Ginninderra water quality is good with only turbidity being high in Lake Ginninderra East. There are improvements in the median values for suspended solids and turbidity in Gungahlin Pond for this period compared to 1998-99.

Water quality in Lake Tuggeranong is fair to good and continues to show an improving trend in total phosphorus, turbidity and suspended solids, however median turbidity results are only fair. Point Hut Pond has poor to fair water quality with elevated levels of turbidity and suspended solids. Run off from residential development in the Point Hut catchment is the most probable cause.

Water quality in the Molonglo River was also good with the median values comparing well with the water quality standards at all monitored sites.

Water quality in the Murrumbidgee River is quite good showing that the ACT has minimal impact on the water quality in the river and landuse practices appear to be effective in minimising pollution from the ACT.


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