The staff at Kent Park near Oxford started Sunday to drain the lake in preparation for planting submerged aquatic plants — one of the last steps of a two-year restoration project.
But the timing is unfortunate because swimmers have been flocking to the Johnson County lake recently after warnings about bacteria and blue-green algae at nearby Lake Macbride.
“Ever since the articles about Lake Macbride, we’ve had huge turnouts,” Brad Freidhof, Johnson County conservation program manager, said of the Kent Park beach. “The water clarity has been great.”
The Kent Park beach reopened this summer after a nearly $3 million renovation intended to improve water quality at the 27-acre lake.
Before the project started in 2016, the Kent Park beach frequently had swim warnings because of high levels of E. coli bacteria from humans and livestock, officials said. The lake also had periodic algal blooms and was included on the Iowa Department of Natural Resources’ list of impaired waters.
The renovation included adding five new catch basins and renovating others to prevent unfiltered runoff from farm fields from reaching the lake. Storm sewer intake structures were installed and crews now are better filtering runoff from parking lots and roads within the park.
The lake was drained for the summers of 2017 and 2018 as crews removed 130,000 cubic yards of sediment, County Conservation Director Larry Gullett told The Gazette in May. Four underwater fish reefs were built and modified to encourage fish spawning.
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Kent Park staff have done weekly water tests at the beach since Memorial Day and results show E. coli levels well within safe recreational standards and no sign of microcystin toxins caused by harmful algae, Park Ranger Charlie Bray said.
Lake Macbride, the state park near Solon, has had swim advisories this summer for E. coli and microcystins. A June 21 advisory for microcystin was the first ever at Lake Macbride.
However, July 1 water tests at the state park beach showed both E. coli and microcystins within safe levels.
Kent Park beach will be out of commission for swimming starting this week as the staff draws down the lake by 3 to 4 feet to plant 10,000 submerged aquatic plants, which provide habitat for fish and trap and recycle excess nutrients.
Freidhof hopes the plants can go in Friday and Saturday, but the schedule is dictated by when a Wisconsin nursery is available to harvest the plants from a wetland and transport them to Iowa.
As soon as the plants are in, Kent Park staff will let the lake refill naturally. Rainfall will determine when the beach will reopen for swimming, Freidhof said.
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