Climate change will likely deal Canberra's blue-green algae a fueling "triple whammy", presenting another challenge for the government as it tries to subdue the potentially toxic plague, experts say.
University of Canberra researcher Dr Fiona Dyer said last year's algal bloom in Lake Tuggeranong was the worst she's ever seen. Her team has determined it could take up to two decades to quell the problem; and that's without the exacerbating conditions of climate change.
"Some of the worst algal blooms on Lake Burley Griffin have been when there's been long, dry periods and hot summers," Dr Dyer said.
"If we have longer, hotter summer periods, it means the lake water is likely to be at temperatures that will support an algal bloom for longer periods of time.
"You'll see those [bad algal blooms] more frequently [and they'll be bigger]."
When water temperatures got above 21 degrees in the right conditions, lakes were likely to have blue-green algae blooms, Dr Dyer said. At 25 degrees, the likelihood increased.
Climate change would see more summer storms washing algae-feeding "nutrients" into Canberra's lakes, Dr Dyer said.
More droughts meant the nutrients would also flood in from bare, dry ground without filtration - the result could be blue-green algae cesspits, causing even more discomfort for local residents and businesses.
"Those three things together really provide a triple whammy to our lakes," Dr Dyer said.
"The really important thing is just making sure we have good ground cover.
"When I say ground cover, it's grasses, it's shrubs, it's trees [that filter the nutrients] ... [so] when you get the summer storms, it's not just washing those nutrients into the lake."
Dr Dyer said the territory government had to make a long-term commitment to fixing Canberra's blue-green algae problem, particularly in Lake Tuggeranong. The lake recorded blue-green algae concentrations more than 100 times the levels recommended for safe swimming last year.
The University of Canberra's project investigating the source of excessive nutrient loads in Lake Tuggeranong would be funded until June 2020. The project, headed by Dr Dyer, formed part of the joint ACT-Australian government $93.5 million Healthy Waterways program; about $51.9 million of which went into wetlands, ponds, and waterway restoration across the territory.
"When I look at what they have to work with within the ACT government, it's a really small amount, and it's not going to fix itself without [long-term] investment," Dr Dyer said.
"It's a program that goes for 10 or 15 years, and that's hard for governments to do because they have this short term focus, but it's a long game [that has] to be played.
"It's already too late, we've already got problems with algal blooms, [but] it's a bit like the climate change scenario - there's no time like now to start doing something about it."
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In early December, 2019, Environment Minister Mick Gentleman said two of the University of Canberra's reports showed wetlands were "not enough" to solve Lake Tuggeranong's blue-green algae plague.
He said the government was committed to addressing algal blooms in the lake so it could be used all year round.
Dr Dyer said the University of Canberra was talking to the National Capital Authority about the potential for a similar blue-green algae project in Lake Burley Griffin, especially since the Canberra Aqua Park had gone in at Black Mountain Peninsula.
Blue-green algae exposure can cause skin irritation, flu-like symptoms and gastrointestinal illness. At its worst, it can make neurotoxins that destroy nerve tissue and are potentially deadly to animals and humans.
