BLOOMINGTON — After last summer’s heat and humidity encouraged excessive algae growth in some city-owned bodies of water, the city this summer will treat them with herbicides in an effort to discourage vegetation from blanketing the water.
But if this year’s efforts don’t work, or even if they do, the city eventually could look to homeowners for help managing city-owned retention ponds.
“It is still yet to be determined … whether or not the city has the financial resources to apply the same practices to every city-owned body of water,” said City Manager David Hales, referring to a $15,000 plan to treat this summer four bodies of water that were the subject of numerous complaints last year.
Problem waters slated for treatment include Miller Park Lake, Tipton Lake and the city-owned Eagle Creek and Golden Eagle retention ponds.
“We may yet have to reach out and ask abutting property owners, homeowners associations and others to contribute or be a partner in helping to keep these waters free of algae during the summer,” Hales said, referring only to retention ponds, not park waters.
Eastside Aldermen Rob Fazzini, Ward 8, and Jim Fruin, Ward 9, said they don’t support the city pushing responsibility onto private groups.
“When someone moves in somewhere and the city is responsible for something, they have a right to assume it’s going to stay that way,” Fazzini said.
Fruin said the retention basins, by handling storm water that would otherwise cause more widespread drainage issues, are a public issue.
Fazzini said he wants the city to be more aggressive this year than the $15,000 treatment plan, even if it costs more.
He said if the treatments end up needing to be applied year after year, the city might be better off in the long run to install a fountain, at a cost of $7,500 plus about $450 in annual electrical expenses, or aeration systems, with initial costs of up to $12,000 plus no more than $4,000 annually.
The fountain and aeration approaches keep algae from growing at the start, whereas some of the herbicide and algaecide treatments only kill vegetation once it appears.
Fruin, noting the uniqueness of each body of water, said he wants to see how this year’s efforts work.
“It’s more art than science, or at least a combination of the two,” said John Kennedy, the city’s parks, recreation and cultural arts director.
He said how different bodies of water are affected depends on a combination of factors, including water depth, animal activity and size of watershed.
While the city this summer plans the reactive herbicide and algaecide approach for treating Miller Park Lake, it also should benefit from measures taken last year after the city lowered water levels in order to repair leaks in the dam, Kennedy said.
While the water was low, the city dredged the bottom of the lake lagoon, where years of sediment had collected.
“That was a very shallow body of water that really encouraged a lot more growth,” Kennedy said. “Once it fills back up we should see an improved body of water.”
He said the lake is still about 4 feet below normal levels, but the city must wait for rain to fill it. He said the lake level should rise about 6 inches for every 1 inch of rain.
Normal Parks and Recreation Director Garry Little said only one small pond — surrounded by trees at Franzen Nature Area — needed to be treated for algae recently. Other bodies of water, including at Ironwood Golf Course, were unaffected by the unseasonable warm weather and recent lack of rainfall.
If any buildup was starting, Little said the weekend rains flushed it away.
Mary Ann Ford contributed to this report.