Cabomba Bund Wall Deconstruction Underway

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The bund wall constructed on the Darwin River, downstream of the bridge on Cox Peninsula Road, is being removed following the first application of herbicide on the invasive aquatic weed cabomba (Cabomba caroliniana).

Cabomba Eradication Program Manager Chris Collins said the project team decided to remove the bund wall sooner rather than later due to current unpredictable rains, promising monitoring results of the water quality and the impact of the herbicide Shark on cabomba.

“The bund wall was initially installed to protect Darwin Harbour from the herbicide,” Mr Collins said.

“However, results from the first application indicate the herbicide was not detected within 1.5km of the bund wall and that its breakdown rate was more rapid than expected.

“Early deconstruction of the bund wall now will ensure that we can safely remove the wall materials before expected monsoon conditions and high spring tides in December.”

While there is only an exceptionally small chance of cabomba seed contamination this far downstream from the actual infestation, all material used in the construction of the bund wall will be removed and stockpiled to  mitigate risk of cabomba spread.

“Very little research has been carried out regarding the seed germination from cabomba, but it is not worth the risk,” Mr Collins said.

“While we are pleased with the results of the intensified application of the herbicide we must remain vigilant and would prefer to have the wall removed in a controlled manner than to blow out due to a change in conditions.”

The Cabomba Eradication Program will continue in 2017.

The Quarantine Zone will also remain in place on the Darwin River between Cox Peninsula Road and Leonino Road crossings until at least November 2017.

The quarantine order prohibits the movement of people and any object, including boats, vehicles and fishing equipment, into or out of this section of river and within the five metres of land adjacent to the water’s edge.

The Eradication Team has also developed a range of community awareness material to help spread the word on the serious risk cabomba places on the Top End waterways, including posters in the local community, fact sheets, information online, a television commercial and social media videos.

“We have fought against cabomba for 12 years, it is vital that we eradicate it and appeal to the community for their support in protecting our waterways,” said Mr Collins.

Go to www.nt.gov.au/cabomba for more information.

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