Lake Ginninderra’s water source is comprised mostly of stormwater discharge from urban and rural areas. It has a catchment of 9,800 hectares, including Gungahlin and eastern Belconnen. Given the urban runoff water source, from time to time, Lake Ginninderra may be subject to health hazards such as toxic blue-green algal blooms or high faecal bacteria counts.
The ACT Government monitors the environmental status of Canberra’s lakes, ponds and rivers and advises changes in water quality conditions in relation to bacteria, blue-green algae and other potentially hazardous conditions, such as flooding. Lake Burley Griffin water quality is monitored for recreational use from mid-October to mid-April only by the National Capital Authority.
In the most recent sample (30 April 2021), Lake Ginninderra rated highly, with Primary (Swimming) and Secondary (Boating) usage permitted.ACT Government
Lake Tuggeranong was closed in all areas for Primary Contact. Lake Burley Griffin was last sampled on 12 April 2021 and there were high levels of blue-green algae in a number of popular locations, preventing Primary Contact whilst Secondary Contact is still allowed.
According to a report by the Canberra Times, Lake Tuggeranong was closed five times in 2016, up from once in 2015 and twice in 2014. It was closed once or twice in previous years, back to 2007. Closures dating back to 2007 show Lake Ginninderra was shut off three times in 2016 due to ‘high to extreme’ blue-green algae levels, as well as once in 2015, 2012 and 2009.
Blue-green algae can be dangerous through the cooler months as primary contact can occur when it washes ashore. Dogs have also been known to suffer ill effects from contact with blue-green algae at any time of the year, when running on beaches or swimming in the water.
Designated swimming areas in ACT lakes and rivers are sampled for water quality according to the ACT Guidelines for Recreational Water Quality. Sampling for primary contact recreation (Swimming) is intended for submersion of the whole human body and not applicable for domestic animals of varying size who may also drink the water, therefore increasing their exposure level.
It is important to review the current advice from the Government and observe any signage. Whilst primary contact in one area of the Lake may not be permitted, this is not necessarily case across the rest of the Lake.
Canberra’s stormwater drains carry water to an extensive network of streams, wetlands, ponds and lakes – including Lake Ginninderra. Everyone can prevent pollutants from entering the waterways by:
- Washing cars on the grass, do not flush chemicals or paint into stormwater drains;
- Prevent leaves and grass clippings from washing down the drain;
- Put rubbish in bins, paper and plastics in the recycling and do not throw cigarette butts in the gutter;
- Clean up after dogs; and
- Compost garden waste and use it to improve garden soil.