BONNYVILLE – Many lakes across the Canadian prairies and North America have become un-swimmable for parts of the summer due to annual and large-scale blue-green algae blooms.
On Nov. 15, Algae Control Canada hosted a virtual public consultation for stakeholders and interested community members to propose a Moose Lake pilot restoration project to solve harmful algal blooms and improve the lake’s water quality with the use of aluminum sulfate.
Attending the information session were a mix of 40 residents and stakeholder representatives.
Invested interest groups invited to the consultation were the Town and MD of Bonnyville, Lakeland Industry and Community Association (LICA), Moose Lake Watershed Society, Cold Lake and Frog Lake First Nations, Métis Nation Region 2, and Kehewin Cree Nation.
The focus of the public event was to explain why Moose Lake was chosen for this restoration project, as well as to gain community support for the treatment of the lake and an application for environmental approval and funding to begin the project in 2023, explained Raymond Menard, the businesses development manager for Algae Control Canada.
In late 2018, the MD of Bonnyville reached out to Algae Control Canada searching for solutions to Moose Lake’s algae problem. At the time, not enough data had been collected to make an informed decision on how to improve the lake’s current condition and determine the main cause of the persistent blue-green algae blooms, said Menard.
“Moose Lake has a lot of data on it. There's been a lot more studies done on that lake than the majority of lakes in Alberta. So, we have a pretty good idea, or at least some indicators, of what was causing problems in the lake, but we didn't know for sure,” he said, noting that a paleo study had been completed at Moose Lake roughly 14 years ago giving more insight into the history of the lake.
The recommendations presented to the MD were to pursue two additional studies, a sediment study and a full phosphorus budget of Moose Lake.
The sediment study consisting of two laboratory tests – Phosphorus Fractionation and a Phosphorus Flux study – was contracted out by the MD in 2019. The phosphorus budget was made possible by grant funding acquired by the Moose Lake Watershed Society.
With the final results of the phosphorus budget being released this summer, researchers were able to determine that 'sediment release' annually contributed one fifth (20 per cent) of the total phosphorus load to Moose Lake, a driving factor of ongoing algal issues.
“Sediment sources of phosphorus are not externally loaded, which would be watershed sources of phosphorus. The majority of the basins had between 60 and 70 per cent of their phosphorus that was driving the algae blooms coming from the sediments (during the summer months) – not from the watershed,” Menard said.
The findings also suggested that treating Moose Lake’s algal issues would be best remedied with the measured use of aluminum sulfate, commonly referred to as Alum.
“We're big proponents of watershed management, but in the case of Moose Lake, even if we managed to return the watershed’s (phosphorus) loads to pre-industrial levels, given the amount of phosphorus that's accumulated in the sediments, we would have to wait a number of lifetimes before we ever saw any real improvements in the water quality,” said Menard.
With the ultimate goal of resetting the lake, staff from Algae Control Canada believe targeted Alum doses to inactivate the phosphorus in the lake could provide 25 plus years of longevity in terms of water quality health and improvements.
“If you combine that with really good watershed management, it could be longer,” added Menard.
Alum is a nontoxic liquid that is commonly used in water treatment plants to clarify drinking water and is used to treat Alberta drinking water, dug outs and reservoirs. However, Alum has never been used to treat large recreational lakes in Canada, although it has been applied to over a hundred lakes south of the border to treat out of control algae growth.
A Canadian first
“It's a technology that's been used in the United States and other parts of the world for decades now, so we're trying to move the needle here in Canada,” said Menard.
The reason Alum has been recommended by Algae Control Canada is because the element permanently bonds to phosphorus and settles back into the sediment layer without remaining in the water column. This prevents phosphorous from being released during seasonal cycles and feeding algae blooms.
According to Menard, Alum is applied by trained specialists from a barge that injects Alum on the surface of the water in specific areas of the lake that experience exceptionally low oxygen levels.
“The Alum very quickly settles through the water column and to the sediment layer where over the upcoming months it actually gets fully mixed in with the sediments. And not only does it strip any phosphorus that's in the water column as it falls through the water, it prevents that reoxidation in the future so it doesn't allow phosphorus to be released from the sediments back into the water column in the future.”
The ball park estimate of carrying out the restoration project based on current prices of Alum is between $13-$15-million, said Menard. This, he notes, is based on a on large scale dose, which he would rather see broken up into smaller doses over the course of five years, but would likely carry a higher price tag.
Menard added that the request for funding the whole project will be sought from the Government of Alberta, and not local stakeholders.
“We’re not asking the MD to step forward with any funding commitment. At this point in time, they've already been very committed to the study and the research on the lake combined with the Moose Lake Watershed Society,” he said.
“The big ask we're making in the community is that once they're comfortable with the idea, that they both support this and let the MD know that it's something that they'd like to see happen... Communicating to them that this is something that they support will make it easier to get approved at the provincial level.”
For more information on the Moose Lake pilot restoration project, visit www.algaecontrol.ca/mooselake
Menard says it is important that those interested and invested in the health of Moose Lake understand what the project proposes and that the information available is provided in a clear and transparent way.
