Weed growth is becoming more visible along Crescent Lake this summer, and city officials say there’s a good reason why.
Jocelyn Lequier-Jobin, director of operations for the City of Portage la Prairie, explains that the herbicide previously used to control aquatic vegetation is no longer permitted.
“In the past, we had always used Reward herbicide for controlling weed growth in the lake,” says Lequier-Jobin. “Last year, we were told that we were not able to use it anymore, that it could potentially cause harm to fish was the reason.”
The change came after Crescent Lake was classified as a fish habitat, meaning any weed control now falls under provincial and federal environmental regulations. The city has since conducted a study to better understand the local fish population.
“We were not sure what the level of fish was in the lake, so we actually did a study and we found that the fish were plentiful. There's no big fish, but there's lots of small ones, sticklebacks and minnows, juveniles and adults,” she continues.
Exploring mechanical harvesting
With herbicide no longer an option, the city is working with provincial and federal authorities to pursue mechanical weed harvesting as an alternative.
“We have been working with the province and DFO to get approval to do weed harvesting with the machine that would go in and cut the weeds,” notes Lequier-Jobin. “We have not received that yet."
A recent city update confirms that environmental compliance is a key part of the approval process and emphasizes that officials are committed to finding safe, legal options.
Conditions vary by area
Lequier-Jobin points out that the west end of the lake is showing the most noticeable growth.
“There’s some areas where we have a lot of the large weeds that are growing up and you can see the tops of them, floating as you look out on the lake,” she adds. “Especially on the west end of the lake, and there's some quite shallow areas there, so that's where it tends to get the worst.”
The east end of the lake has less vegetation but is seeing more algae accumulation, which Lequier-Jobin says could be contributing to odours in the area.
“More likely it would be from algae that would give a smell,” she remarks. “Generally the weeds when they're active, they wouldn't really be causing a smell. It would be more as they die.”
Weather playing a role
Summer rainfall can help improve water flow and reduce weed buildup, but dry conditions have made that difficult.
“If you can get water flowing, it really does help a lot with it,” Lequier-Jobin explains. “We do pump water from the river into the lake, but when it's dry, we can barely keep the lake levels up, never mind get a good flow.”
She says lake levels this year are about average, though pumping depends on the Assiniboine River, which is prioritized for other uses like drinking water.
Selective harvesting likely
If approval is granted, Lequier-Jobin says the weed harvester wouldn’t be able to cover the entire lake due to time and regulatory limits. Harvesting is only permitted from mid-June to mid-September, outside of fish spawning seasons.
She adds that repeated use over several seasons should reduce future regrowth.
“They do say that as you do it each year, it tends to reduce the regrowth in future years,” continues Lequier-Jobin. “So we're hoping that over time it will become less and less of an issue.”
Residents staying patient
Despite the visible changes on the water, the city says public reaction has been mostly understanding.
“We have heard from some people. I wouldn't say we've had a lot of complaints,” says Lequier-Jobin. “In general, people are understanding of what we're having to deal with right now, but I'm sure everyone would like to see the lake cleaned up a bit.”
As for the fish themselves, she notes that while they’re plentiful, they’re not the type people usually fish for.
“Some people do use it for bait because they're quite small fish,” she says. “It would be more considered as feeder fish for a larger species.”
The city says it will continue sharing updates as they become available.
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