JOHNSON COUNTY — The lake at a popular Johnson County park may need some drastic help to improve the water quality. And the preferred solution may be to drain the lake and start over.
In seven out of 14 weeks this summer, the water at F.W. Kent Park west of Tiffin tested higher than allowed for E. coli and other potential health hazards The 27-acre lake is on the state’s list of impaired waters sand currently has high levels of both algae and pH. Water quality experts for the Iowa Department of Natural Resources (DNR) presented options to rehabilitate the lake at an open forum on Thursday.
Brad Freidhof, Conservation Program Manager for Johnson County Conservation, said since Kent Park Lake was created in the 1970s, the county has tried various techniques to keep the water clean. That included making retention ponds to catch runoff with agricultural chemicals and limiting the use of fertilizer on county-owned park land surrounding the lake.
But as Freidhof stirred the lake water on Thursday he said he fears conservationists are losing the battle.
“The problem is right here,” Freidhof said adding “the water looks clean but it doesn’t smell clean.”
The algae is the most visible water problem at Kent Park now. But Freidhof said the phosphorus you can’t see in the silt and sediment in the lake bed itself is also limiting recreation.
Conservation staffers believe the fishing isn’t as good as it once was.
The latest water quality testing posted at the entrance to the beach area shows the lake below warning levels.
But Freidhof said about half the time this summer, staffers had to post “swimming not recommended” signs as a warning when E. coli and other bacteria levels exceeded certain limits. That’s given the lake a reputation in recent years.
“They (visitors) get out here, see those signs and they get that disappointed look on their faces and parents take it hard. Some of them will turn around and take the kids home,” he said.
The water improvement plan for Kent Park, just in the draft stages now, could include variety of ideas like convincing nearby landowners outside the park to change farming practices to limit fertilizer runoff.
But Freidhof said with the pollutants embedded in the sediment now, shutting down the lake for more than a year to drain the water and scrape the bottom when it dries out maybe the only long term solution.
Sara Piere, who was camping with her family at Kent Park, wasn’t sure if the radical solution of draining the lake would be her first choice. But she said she was a fan of cleaner water at the park.
“I am concerned, I have grandchildren out there that enjoy swimming and it’s hard to camp at a place you can’t go swimming as an activity,” she said.
Freidhof said the conservation department hasn’t figured out what it would cost to drain the lake and rehabilitate it. But the county wouldn’t probably go ahead only if there is support from park users and available funding.