Extensive weed treatment takes place between May and August each year, with more than 90 per cent of the program completed as G-MW treats hundreds of kilometres of channel.
G-MW Water delivery services general manager Warren Blyth said submerged weeds affected water flow, promoted silting and caused issues with automatic regulators, which could reduce the ability for G-MW to deliver water to its customers.
“The irrigation shutdown period allows the perfect opportunity for us to undertake a range of treatments, which include de-watering channels and herbicide spraying or injections,” Mr Blyth said.
“The type of treatment often depends on the type and extent of the weed and the characteristics of the channel, and our water delivery and infrastructure delivery services teams work closely together to carefully plan out a targeted program each year.”
Weed treatment is currently under way in areas across the east, central and west irrigation areas.
Those residents affected will be notified and will not be able to use channel water for stock, horticulture and broad-acre crops for a specified time.
G-MW doesn’t guarantee water supply during winter and has advised customers to secure a winter water supply by filling their tanks or dams.
Mr Blyth said G-MW had been researching and testing options to improve its weed treatment program, and this year had trialled a new chemical called Flumioxazin.
“In diluted form, Flumioxazin has a very low toxicity to humans and animals,” Mr Blyth said.
“While G-MW’s channel network is not a natural waterway intended for use as habitat for fish or other animals, it is important for us to minimise impact to aquatic life and the environment.”
Flumioxazin was used on a smaller scale last year and is being trialled at four sites in the Murray Valley Irrigation Area this winter.