Burdekin Shire Council has decided against lending its weed harvester to the Townsville City Council as the threat of transferring Sagittaria platyphylla to the region’s waterways was too great, according to Mayor Lyn McLaughlin.
Townsville currently has an infestation of the noxious weed in Ross River. Sagittaria platyphylla is a declared Weed of National Significance due to its invasiveness, potential for spread and economic and environmental impacts.
Cr McLaughlin said the Burdekin Shire Council had been approached by Townsville City for use of the Shire’s weed harvester.
“We often lend the harvester to local government areas including Townsville, but we feel the massive threat to our Shire’s irrigation assets and aquatic biodiversity by this invasive weed is too great in this instance,” she said.
“Many years ago Council received State Government funding for the purchase of the weed harvester and trailer and at that time there was an agreement that it would be made available to other councils.
“However, this agreement expired on 30 June 2004 and the harvester became the property of the Burdekin Shire Council.”
Cr McLaughlin said that the weed had been declared Category 3 Restricted Matter under the Biodiversity Act 2014.
“This means it is Burdekin Shire Council’s responsibility to ensure it is not intentionally imported into our region and it is Townsville City Council’s responsibility to contain the spread the weed,” she said.
“In our region the Lower Burdekin Water controls 300km of irrigation channels which deliver water to 41,500ha of irrigated land.
“SunWater also has a range of waterways it controls and there are numerous lagoons and wetlands in our region which would be decimated if this weed should take hold.
“We have a responsibility to our farmers and the economic health of our Shire to ensure it never gets in to the waterways.”
The Mayor said Council had discussed the situation with a number of agencies and none could guarantee that – even with treatment and cleaning – the harvester would be 100 per cent free from the weed and its seeds.
“It is nearly impossible to control the weed due to its many methods of reproduction through seeds, tubers and rhizomes, its tolerance to both herbicides and mechanical removal, the aquatic habitat it invades and persistent seed banks,” she said.
“There are currently no effective herbicides registered for use against Sagittaria, although several are approved for minor use by the Australian Pesticides and Veterinary Medicines Authority.
“It is a highly invasive and rapidly growing plant that can overtake water bodies up to one metre in depth.
“Severe infestations block irrigation channels and drains, leading to restricted flows and increased trapping of silt.
“It chokes wetlands and waterways, which adversely affects aquatic biodiversity.
“Infestations can also have detrimental impacts on recreational activities, such as boating, swimming and fishing, and reduce visual amenity of waterways.”
Cr McLaughlin said annual costs to Goulburn-Murray Water for managing infestations in creeks, channels and drains had been as high as $2 million in some seasons.
“This is a cost burden our ratepayers will not be able to afford,” she said.