Lake Okabena's clarity improves, people tell watershed board
Jul. 7—WORTHINGTON — Whether it's Canadian wildfire smoke or the success of many efforts over years, the clarity of Lake Okabena is improving — at least, that's what people are telling the Okabena-Ocheda Watershed District Board of Managers.
"Whatever's happened the last few years, and especially this year, Lake Okabena is amazing," manager Jay Milbrandt said during Wednesday's meeting. "Everyone I talk to, they cannot believe — we're in July, and the water is fantastic. It feels clean. There's no flakes, there's no algae. It's just great. This is the best year I've ever seen in the lake, and I feel like it's gotten better every summer."
"With every step that's taken," said Rolf Mahlberg, board president.
And, at least as of earlier in the week, there was no sign of Lake Okabena's stinkiest, most toxic summer visitor — algae blooms, smelly overgrowths of algae that can produce toxins that can sicken people and animals, including those living in the lake.
"What I'm saying is, we had perfect conditions for an algae bloom for the last two weeks," said Watershed Administrator Dan Livdahl.
"And nothing," Mahlberg added.
Milbrandt believes the improvements correlate with the watershed board's project at the former Prairie View Golf Course, where water storage ponds filter silt and nutrients from runoff before it can reach Lake Okabena.
Livdahl also theorized that the Canadian wildfire smoke lingering in the atmosphere may have prevented some sunlight from reaching the algae and fueling a bloom. However, Lake Ocheda still had its usual algae bloom issues.
"People are remarking about how great this is, it's the best they've ever seen," Milbrandt said.
Livdahl said he was sure that the watershed's projects helped, but it seemed unlikely that they were the only cause of the improvement.
The Prairie View project has had some maintenance issues since it was completed, in that its filters have been plugging up quickly, as water has eroded the banks, to deposit their soil there. When it accumulates, it turns into a rock-like wad that water can't easily penetrate. The filtered material needs to be removed, and the sand will need to be replaced if it is to continue filtering.
The watershed board asked Livdahl to get bids for replacing the sand.
The managers also discussed another growing problem in Lake Okabena — curly leaf pondweed, an invasive aquatic species spreading especially aggressively on the western shore of the lake this year.
Mahlberg warned that snagged fragments of the weed can proliferate, so attempting to tear out or cut the leaves would be counterproductive.
"If you don't have clear water, you don't get plants," Livdahl explained, adding that the weed seems unlikely to take over the entire lake, as the water quality would likely not support that.
In Minnesota, managing invasive aquatic plants either mechanically or with herbicide requires a permit from the DNR.
