Lake Winona once had at least 10 varieties of native plants, a fish population dominated by bullheads and a sandy, stony bottom.
Nowadays, seven native plants have disappeared, invasive carp rule its shallow waters, and its bottom is covered with inches of muck. The long, skinny lake is polluted with chloride and phosphorus, and those pollutants have been migrating downstream to Lakes Agnes and Henry. These three lakes drain north through Lake Le Homme Dieu and Lake Carlos, and eventually into the Long Prairie River.
A team of local residents is meeting to address chloride. And the plan to clean up phosphorus is once again before the public. Called the Lake Winona Phosphorus Reduction Project (Total Maximum Daily Load) Report, it outlines the problems facing the lake and calls for cutting phosphorus levels in half. The public has until Wednesday, May 26, to comment on the plan.
Phosphorus is an essential element for plants, but too much of it can create a lake unsuitable for fishing or recreation, and even lead to toxic algae blooms. It ends up in lakes from fertilizer runoff, erosion and storm water runoff. In Winona, the biggest direct source of phosphorus comes from the Alexandria Lake Area Sanitary District, which treats the area's sewage and discharges the wastewater directly into the lake. The district has been steadily reducing the amount of phosphorus it puts into the lake.
Another major source is the city of Alexandria's storm water runoff. When it rains, the water runs into gutters and then into pipes that carry it to the lake. LaGrand Township also contributes some phosphorus via storm water.
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Phosphorus also comes from the lake itself, especially when the sediment gets stirred up on the bottom. That's why planners want to get rid of the carp, which are notorious for nosing around on lakebeds and stirring up pollutants.
Restoring Lake Winona is a "long term effort but can be accomplished," the report says. To accomplish it, everyone adding phosphorus to the lake will have to cut back, and the carp population will have to be controlled.
Before restoration will be complete, there will likely be a time where Winona will switch from clear to turbid water conditions and back, as phosphorus levels slowly decline.
Cleanup efforts date back to 1990 with the 1990 Agnes-Henry-Winona Clean Lakes Project, led by Douglas County with involvement from the City of Alexandria, LaGrand Township, and the sanitary district.
"While the Clean Lakes Project report had many good recommendations, it does not appear many were implemented, or that any one local agency had lead oversight authority for management of Lake Winona," the report says. "ALASD, however, completed all the Clean Lakes Project recommendations related to the (treatment plant) operation."
The Lake Winona Phosphorus Reduction Project itself dates back several years, with a pubic hearing in 2016. It estimates cleanup removal at several million dollars, and the plan has been something of a political football, with few willing to take the lead. However, the treatment plant's new operating permit requires it to take the lead on chloride.
Besides managing carp, the current plan calls for restoring native aquatic plants, and managing phosphorus releases from lake bottom sediment.
Among steps local government might take:
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- Help landowners reduce soil erosion
- Establishment diverse native vegetation
Minimize use of fertilizers, herbicides and salt
Some action has already been taken to protect Lake Winona, including drainage improvements at Thomas Drive and adding a city storm water pond at the airport that treats storm water before it goes into Lake Winona.
The city of Alexandria also trains its staff on storm water management, sweeps streets at least twice a year, and cleans out sump catch basins and manholes annually, among other steps.
To comment on the plan, email bonnie.finnerty@state.mn.us or mail comments to Bonnie Finnerty, Watershed Division, Minnesota Pollution Control Agency, 7678 College Rd, Ste 105, Baxter, MN 56425-9525.
