Goulburn-Murray Water (GMW) recently conducted a weed treatment trial that was the first of its kind in the world.
In a channel just west of Cobram, GMW trialled a “flowing injection” method of weed treatment with Flumioxazin.
Flumioxazin is a fast working herbicide that has minimal effect on fish life. In diluted form, Flumioxazin has a very low toxicity to humans and mammals, although there is a short withhold period that needs to be followed.
A flowing injection involves the weed treatment chemical being dispersed at the top of a treatment zone – a section of the channel the water will flow down from. The water is drawn through the treatment zone at a constant flow and then stopped once the chemical nears the end of the treatment zone.
With this particular product we are trialling different application types to assess efficacy on varying weed types. GMW also treats weeds by direct injection of chemical into a static body of water, surface-spraying channels, and by dewatering channels and surface spraying the exposed soil.
GMW Weed Maintenance Technical Adviser Danielle Ick said adding flowing injections to these methods would potentially allow GMW to be far more comprehensive in its treatment of weeds.
“Flowing injections are very beneficial when treating parts of our channel network that are difficult to access,” she said.
“Traditionally, we would need access to almost the full length of the channel bank to spray the weeds, whereas with flowing injections we may simply need access to a regulator.”
The flowing injection using Flumioxazin was the first of its kind.
GMW has treated more than 230km of channel with Flumioxazin in 2022, up significantly from the 8km of channel it was used on in 2021.
“This winter, there has been a very strong focus on treating the weeds in our channels,” Ms Ick said.
“Weeds can dramatically decrease flows and prevent irrigators getting the water they need when they need it.
“The results of our extensive weed treatment program are looking promising and we’re hoping that some irrigators will enjoy improved flows when the Irrigation season starts because of it.
We will continue to monitor the sites we have treated in the coming months.”
The Irrigation Season begins on 15 August 2022.