As part of an ongoing effort to improve Fountain City Lake, the City of Knoxville is again taking steps to remove an invasive weed species, followed by a proactive maintenance treatment.

Work at the lake will begin Tuesday, Aug. 27, and City Stormwater Engineering has scheduled part of the work to be performed by inmates participating in the Knox County Sheriff’s Office voluntary work release program.

Fountain City Lake is not owned by the City, but the City has been collaborating with the Lions Club to assist in maintaining the one-acre lake.

The current weed-removal work will involve a slight draw-down of the lake, then use of mechanical cutters and rakes to remove the invasive parrot feather weeds that are overwhelming the lake, said David Hagerman, City Stormwater Engineer.

“City Public Service workers will then vacuum out the lake’s fish screen that is contained in the outlet structure to remove any weed fragments that get trapped in it,” Hagerman said.

Following the mechanical harvesting, a contractor will treat the weeds with a systemic herbicide that is safe for humans, fish, birds and the environment. The project should be completed in about two weeks.

The City has also added 50 grass carp to feed on the soft new growth.

Maintaining Fountain City Lake, a beloved and iconic part of Fountain City, is a process that will continue to take persistent effort and patience, Hagerman said.

Since 2014, City workers have completed a number of projects to improve Fountain City Lake, including repairing the fountain and pump house to aerate the water. Wetlands also were planted to remove shallow, stagnant areas that were conducive to algae growth. Duck feces have also been removed from the bottom of the lake.

Last December, crews removed heaps of invasive aquatic weeds from Fountain City Lake. The weeds had spread rapidly and had covered a large portion of the water’s surface. The invasive species that were yanked out filled three trucks.

The source of the non-native aquatic pest? People dumping the contents of their personal aquariums into the lake.

Parrot feather grass and other watermilfoil plants originating from other continents are sold in local pet stores in the United States to beautify home aquariums, but they can wreak havoc when unleashed into natural water systems.

In the case of Fountain City Lake, the parrot feather was again flourishing by this summer – just months after the bulk of it was painstakingly removed by hand.

This time, the second round of removal – paired with the maintenance treatment and the carp – is expected to better control the parrot feather.

The City is investigating options for long-term annual maintenance to assist the Lions Club, Hagerman said.