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Every year, thousands of people flock to the north-west Victorian town of Lake Boga to swim, ski and kayak. However, this year, there are fears that the town's main body of water may be off limits. Since March, Lake Boga has been recording blue-green algae levels of at least three times the safe limit, in what is the second-longest bloom at the destination since records began in 2007. Goulburn Murray Water (GMW) issued a warning earlier in the year and urged people not to use the lake. Lake Boga Ski Club secretary Chris Lahy said things were "very concerning" for the club, after it was forced to move its first wakeboarding clinic of the season to Lake Charm, 24 kilometres away. "I'm at a bit of a loss to understand where we go as a club if we can't enter the water and do our activities that we've planned for the season and beyond," he said. Mr Lahy questioned the handling of the outbreak. "I've been here for 17 years and I've seen the lake being managed in myriad different ways," he said. "This is going back to what it used to be, an ephemeral lake, where they're not going to run water through the lake, replenish the water flows, move water on." Concerns over 'no plan' Swan Hill Rural City Council Mayor Stuart King this month called for an urgent meeting with GMW to understand its plan of attack for the summer. "Goulburn Murray Water has been dealing with blue-green algae at Lake Boga for years now. It seems to be almost an annual problem," Cr King said. "I would have thought by now they would have had some sort of solution, some sort of management solution to minimise the occurrence of the blue-green algae and how long it hangs around for. "So, that is of concern that they don't really have a plan." Cr King said algae was generally an issue during the warmer months, but given it had lasted throughout winter, he was concerned about the impact it would have during the lake's busy period. "[The lake] is a hive of activity, particularly over that Christmas-January period and we want to be able to offer that to visitors to our region. Algae 'hard to predict' In a statement, GMW said it had been in regular contact with all stakeholders regarding the algae warning and it welcomed collaboration between stakeholders, including Swan Hill Rural City Council. GMW said it was unable to prevent blue-green algae because "population [of algae] undergo fluctuations that cannot be predicted". It said it was not unusual for algae warnings remain in place for long periods of time. University of Technology Sydney associate professor Simon Mitrovic said removing blue-green algae was "a very, very hard" process. "Unfortunately, there's no sort of silver bullet that can solve the issue everywhere," he said. "But you can look at approaches that target a particular lake to try to control it, once you understand what's causing it." Dr Mitrovic said if the conditions remained suitable for the particular blue-green algae that was blooming, or a transition of different species occurred over the coming months, then Lake Boga, which has a water capacity of 38,000 megalitres, could potentially be out of action for the entire summer. However, he said high rainfall could change conditions. GMW water quality manager Greg Smith said the water authority wanted to remove the warning as soon as possible, but the algae was persistent and hard to predict. "We've experienced it in our whole region and particularly up there [at Lake Boga] for many decades now and it's proven very resilient through all sorts of weather, flows and water level conditions," he said. "We no longer even attempt to provide a forecast, but we will keep up the monitoring and we will remove the warning as soon as the levels drop below that high trigger." The warning will remain until blue-green algae is recorded at a safe level.
