Treatment of Lake Goollelal and Lake Joondalup

Monitoring of midge larvae numbers conducted by the three bodies also showed an increase in midge activity, and to provide relief to residents, treatment of the wetlands occurred on Wednesday 30 November 2016.

Midges are naturally occurring in wetland ecosystems on the Swan Coastal Plain. The nuisance problem of midges at Lake Goollelal and Lake Joondalup is a symptom of a disturbed ecosystem, and are also influenced by water temperature and water levels.

Nutrient enrichment within the catchment resulting from the use of fertilisers on gardens, sports grounds and agricultural properties, as well as septic tank leaching and stormwater run-off, may also impact the prevalence of midge. 

Joondalup Mayor Troy Pickard said the treatments aimed to eliminate a future midge nuisance.

“Lake Goollelal and Lake Joondalup are important wetlands and ecosystems, and every endeavour has been made to protect the animal life supported within them,” he said.

“The species of midge that breed in both lakes do not bite or cause any adverse health effects, however when in large numbers midge can cause a nuisance to residents living around the wetlands.

“Continued monitoring will occur, and should midge larvae numbers become elevated, a secondary treatment will take place.”
Wanneroo Mayor Tracey Roberts said the Cites of Joondalup and Wanneroo and the Department of Parks and Wildlife had a midge management agreement which took a balanced approach to controlling the insect—with treatments undertaken as a last resort.

“There is a concern that midges may become resistant to the larvicide if overused,” Mayor Roberts said.  

“However, the lake was treated last month due to the recent high larvae numbers and swarms that were becoming a serious nuisance to the community.”

Important Background Info

Residents wishing to reduce the likelihood of midge being attracted in and around their homes are also encouraged to take the following steps:

• Use yellow, low wattage globes (25 or 30 Watt) around the home.
• Reduce lighting to external areas.

Residents living near a lake can help by doing the following:

• Wash your car on the lawn rather than the driveway or street.
• Use nutrient free detergents.
• Use slow-release fertilisers on lawns and gardens. 
• Plant local native plants in your garden.
• Dispose of household waste appropriately, not down stormwater drains.
• Properties that have been provided with sewer, but are still using septic tanks around the Wanneroo area, should decommission these septic tanks and effluent disposal systems and connect their property to the Water Corporation sewer.

People who are sensitive to chemicals can be notified 24 hours prior to any treatment of the lakes.

Anyone who would like to be added to the chemical sensitivity list can contact their local government authority –

City of Joondalup residents – 9400 4933
City of Wanneroo residents – 9405 5000