1998-1999

Executive Summary

DECCEW undertakes a water monitoring program for the ACT which 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 adequate.

This report provides the ACT community with the results of the program and the level of compliance 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 above the long term average. As a result, streamflow was also higher than for last year and has had observable effects on water quality in some areas with elevated levels of suspended solids and turbidity. The drought caused a reduction in surface vegetation leaving soils prone to higher erosion. The increased rainfall and corresponding runoff has facilitated this erosion.

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 flow dependent indicators a flow concentration relationship has been used to determine compliance with the water quality standards.

Trend analysis of data available for the period 1992-1999 has been carried out for sites with sufficient data for trends to be analysed.

Water quality in the ACT for lakes and streams is generally good. 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.

Water quality in Lake Tuggeranong continues to improve as the catchment stabilises after extensive development. Lake Ginninderra is quite good and stable considering the development occurring higher in the catchment. Point Hut Pond and Gungahlin Pond have fair water quality and are showing signs of contamination from erosion with elevated levels of turbidity and suspended solids.

Report

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. Water quality in the Molonglo River was also quite good with the median values complying with the water quality standards at all sites monitored, with the exception of turbidity.

For the full water quality report please download one of the sections from below:

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