The City of Castlegar is trying to get a handle on what causes the algae blooms that have bedeviled the ponds at Millennium Park for several years.
Municipal services manager Chris Hallam told city council this month that although staff have tried various ways to minimize the blooms, they don’t actually know what causes them.
The city hired a consultant in 2022 to come up with potential solutions. But Hallam said it’s hard to know what will work without a better understanding of why the algae forms.
As a result, he said staff are taking a step back to collect water quality data and understand the source of the problem. Crews are now regularly taking samples from various locations to understand where the nutrients that algae thrive on are introduced.
“Is it coming from geese feces? Is it coming from the groundwater because it’s high in nutrients, or is it coming from fertilizer?” he asked. “There’s lots of ways that nutrients can get introduced into this water, so we’re going to get that understanding, and from there, we’ll be able to recommend better solutions.”
Hallam said the shallowest pond grows algae “the minute the sun looks at it,” so they propose not to fill it with water this year, and instead to bring in some clean sand, which can be graded and groomed like the other beach areas around the ponds.
They’re also trying to increase the flow of water into the ponds, as a quicker turnover makes algae blooms less likely. The downside is that the ponds could potentially be colder, but Hallam said he thinks it’s the lesser of two evils.
The city will also reintroduce some geese control measures at the park. In the past, dogs have been used to scare the birds away, with some success, Hallam said. They also plan to use flagging to discourage geese from setting up nests and breeding in the area.
This year’s city budget includes $10,000 to support the anti-goose campaign as well as the water monitoring program. Another $250,000 has been tentatively included in next year’s budget to implement whatever algae solution staff come up with, but Hallam said that’s just a rough estimate.
Admit defeat?
Councillors had mixed feelings about whether ridding the ponds of the algae blooms is worth the effort.
“I’m wondering if we should just admit defeat on the ponds and not drain them,” councillor Brian Bogle said. “Because if it’s going to be in the same condition as it was last year, I don’t think we should bother.”
Bogle suggested instead filling the ponds with sand and converting them to a play area while looking for another attraction for the park.
Mayor Maria McFaddin, however, said she was comfortable giving the ponds another chance since the city has a plan to address them.
“I think it’s worth giving it one more year,” she said. “I don’t think we’ve put the same amount of attention into really understanding the problem. We’ve tried to do mitigation, but not necessarily get to the root of the problem.”
McFaddin said if the city is in the same position next year, she might feel differently.
She also asked about a previous plan to improve circulation in the ponds using an aeration system. Hallam said aeration comes with safety considerations and would require closing areas of the ponds. He added that without knowing the source of the problem, they can’t be sure if aeration would improve things.
“It’s really hard for us with confidence to make recommendations to council and spend not insignificant amounts of money on things that ultimately might not have a positive, meaningful outcome,” he said. “So the hope is that we can, once we better understand [the issue], hone in on making recommendations of the absolute right solutions.”
Councillor Cherryl MacLeod agreed it’s worth the investment to try to solve the problem, but if the shallowest pond can’t be fixed, she wondered about moving the water park there from its present location at Kinsmen Park.
Councillor Darcy Bell said he likes the plan Hallam outlined and didn’t think it came with a high price tag, “so I think it behooves us to give this one more year.” Bell said he believes many families in the community would love to see the ponds working properly.
The blooms aren’t harmful to people but make the pools uninviting to swimmers. They’ve also led to periodic closures.
