Drones are the new weapon in the war against invasive weeds clogging Gunbower Creek.
North Central Catchment Management Authority and Goulburn-Murray Water trialled drone-spraying technology alongside conventional boat-based spraying to tackle the highly invasive pale-yellow water lily in a section of the creek over summer.
Pale-yellow water lily reduces creek capacity for irrigation and water for environment delivery, and restricts access for recreation such as boating, fishing and kayaking.
It can also impact threatened native plant and fish species, including the critically endangered silver perch and the threatened golden perch and Murray cod.
The summer’s spraying program focused on an 80km stretch of the creek between the National Channel and Koondrook Weir, mostly via boat-based spray rigs.
Drone spraying was trialled along a small section of the creek at Jumbo’s Cut.
“We wanted to find a way to treat sections of the creek we couldn’t access by boat, and test whether it could be done successfully,” North Central CMA project manager Amy Russell said.
“It is early days, but we couldn’t be happier with the results so far,” she said.
“Not only were we able to access hard-to-reach areas, but if the trial proves to be effective, it may allow us to reduce the amount of spray we use to effectively control this weed.
“The drone also helped prevent the ‘umbrella effect’ occurring, where the leaves at the top protect the leaves below. The down draft from the drone allowed the spray to penetrate deeper into the dense infestations.”
North Central CMA is hoping to use the trial results as a basis for further trials.
“The community is behind our goal to reduce the impact pale-yellow water lily has on the creek and prevent it from entering nearby wetlands such as Reedy Lagoon, but it’s a big job,” Ms Russell said.
“Gunbower Creek is important economically, culturally and environmentally to this region, which is why managing this weed is so important.
“We know spraying works. Over the past four years, the program has reduced the infestation by about 80 per cent in treated areas.”
The spray used is fish- and frog-friendly.