Aquatic Weed Trial

InvestmentThe trial is supporting the Integrated Management of Aquatic Weeds project. The trials are being funded by a collaboration between the CSIRO, Australia’s lead science agency, and the Queensland Department of Agriculture and Fisheries. Townsville City Council provides in-kind and logistical support of the trials.
JobsThe project offers opportunities to develop tropicalised jobs in aquatic weed management.

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Strategic Purpose
  • To trial new tools to contribute to the integrated management and control of Cabomba, an invasive submerged aquatic weed.
  • To reduce the social (recreation), financial and environmental costs and impacts of aquatic invasive weeds on our urban waterways.
Status Underway

Townsville City Council in conjunction with CSIRO, Australia’s national science agency, and the Department of Agriculture and Fisheries (DAF) are conducting aquatic weed management trials in Townsville. The project will investigate the management of cabomba, a major aquatic weed obstructing waterways, affecting recreational activities, water quality and native species.

The project seeks to improve the management of cabomba through two trials - biological control and an aquatic herbicide. The trials will complement Council’s already highly successful aquatic weed harvester that operates in the Ross River. If successful, the trials will provide additional tools for Council and other natural resource managers and farmers to control cabomba.

The trials are scheduled to take place in August 2022.

Residents close to project sites will be updated with details about the trials prior to any work commencing.

What is Cabomba?

Cabomba caroliniana is a submerged aquatic weed of permanent and slow-moving freshwater bodies. Cabomba is highly invasive and can rapidly infest waterways. Its sale and distribution are prohibited in most states and territories because of its invasiveness. It has also been declared a Weed of National Significance and is regarded as one of the worst weeds in Australia.

Does Cabomba weed cause any damage?

Cabomba affects water quality, interferes with recreational activities, and poses a risk to public safety as swimmers may become entangled. It forms dense monocultures in aquatic ecosystems, which reduces light availability through the water to native plant species. Extensive infestations have been shown to displace submerged vegetation, including native species. Cabomba can also impact infrastructure of dams supplying drinking and irrigation water. It also reduces water quality through discolouration and tainting.

How does Council currently manage Aquatic weeds on the Ross River?

Aquatic weed control tools available include a combination of mechanical, biological and chemical treatments.


Council uses an Aquatic Weed Harvester (AWH) for broadscale mechanical extraction of Cabomba, water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) from recreational areas of the river to a depth of between 1 and 3 meters.


In the past council have successfully used biological control, a species of introduced weevil, to manage salvinia (Salvinia molesta) a floating aquatic weed.  Up until now there has not been a biological control agent available for Cabomba. The trial in August will monitor the effectiveness of this new control tool.


For surface floating weeds, water hyacinth and water lettuce, Round-up Biactive herbicide is used along the edges of the Ross River where the weed harvester cannot reach because it is too shallow.  There are no appropriate chemical controls available on the market for submerged aquatic weed control. The trial in August will monitor the effectiveness of a new herbicide to control Cabomba.

Frequently Asked Questions