Canberra: Australia's largest hydroelectric power generation company, Hydro Tasmania, maintains 28 major dams in the state of Tasmania, and a big part of its maintenance task is keeping on top of weeds.
Company spokesman Tony Harris says, until now, abseilers have carried out the task. "We must manage those weeds and those trees in particular and part of that was that we would abseil down the dam with a backpack on and spray those trees," he says.
But with walls more than 100 metres (330 feet) high, the risks are high too.
"Sometimes a few rock moves, you can hear it from quite a distance, so basically work ceases, you watch what's happening and you just make sure you just cautiously move out of the way," says abseiler Brad Judge.
"They have to be very vigilant and those rocks, they're possible 20 kilos, 30 kilos in size or weight," Harris adds.
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To eliminate that danger, Hydro Tasmania has had a drone built purposely to spray the weeds.
Drone operator Andrew Davies is getting it ready for the task. "We ended up sourcing parts from different places around the country and the world, putting them together because there was nothing on the market existing that could spray vertical surfaces in the world," he says.
The new technology is proving its worth.
While the abseiling crew takes around four days to do the job, the drone does it in less than one.
"The process is flying up to the weed, looking at it with the first-person view camera, putting it in the middle of the crosshairs and hitting the weed," Davies explains.
While the new technology is safer and cheaper, Hydro Tasmania will still need to use roping contractors for some jobs where the vegetation can't be accessed by drone.
"I've had to carry a lot of gear and brush cutters and bush saws and hack my way through the forest just to get my way to the top of a cliff to find some trees to abseil down," says Judge.
There are hopes the technology will be the future for dam maintenance in other places too.
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