Blog: City Blog

Small Aquarium Dumps Result in Truckloads of Invasive Weeds Pulled from Fountain City Lake

Invasive weeds pulled from Fountian City Lake

Three truckloads of invasive weeds originating from personal aquariums were removed from Fountain City Lake.

Weed trimming season may be over for most, but heaps of invasive aquatic weeds were pulled from Fountain City Lake this week.

The weeds had spread rapidly and were covering a large portion of the water’s surface.

The source of those weeds? Believe it or not, it’s from citizens dumping the contents of their personal aquariums into the beloved Fountain City Lake. The lake is not City-owned, but the City works collaboratively with the Lions Club and other community stakeholders to maintain the lake.

Non-native aquatic plants like parrot’s feather grass and other watermilfoil plants originating from other continents are sold in local pet stores in the United States to beautify aquariums, but are invasive and can wreak havoc when unleashed into our natural water systems.

Fountain City Lake covered in invasive aquarium plant

Fountain City Lake covered in invasive aquarium plant

A look at the impact of the non-native, invasive weeds prior to the removal effort.

In fact, when the water was recently drained down to mitigate the algae problem at Fountain City Lake, a rainbow assortment of aquarium gravel colors was discovered.

“People may have the intent of giving their aquarium inhabitants a chance at life, but the reality is the fish and amphibians have almost no chance of survival, while the exotic plants are going to overtake native vegetation that serve a vital purpose in our waterways’ ecosystems,” said David Hagerman, Stormwater Engineer for the City of Knoxville.

“Fountain City Lake is giving us a concentrated look at the level of damage a few little invasive plants can cause.”

Inmates participating in the Knox County Sheriff Department’s Work Release program spent two full days working on the lake during the first week of December. The pile of dead weeds yanked out of the 1-acre lake amounted to about three truckloads.

The City also added a treatment for the invasive weeds last month as well as 25 grass carp to feed on the plants.

With the help of slow-growth winter temperatures, officials are optimistic that these efforts will slow and eventually eliminate the unwanted vegetation.

The water has been lowered so that contractors can finish plantings for a wetland area designed to help with Fountain City Lake’s recent algae issues caused by overfeeding of the lake’s duck and goose inhabitants.
Restoring Fountain City Lake has been a long process, but City officials knew from the beginning it would take persistent effort and patience to fix problems that were decades in the making.

The work started in fall 2014 with the City's repair of a leak in the lake's earthen berm, allowing water levels to be managed and the lake to reach its proper depth.

Workers then repaired the fountain and pump house to aerate the water and discourage algae growth. Late last fall, a contractor crew finished construction of the gabion baskets, which were then filled with more stones and soil for the wetlands.

The contractor also removed more muck (contributed to by the feces of overabundant ducks) from the lake’s bottom. The final step was planting and filling in the wetlands.

Wetland plantings

The water of the lake was lowered to install native plants in the wetland area.

To date, the City has invested a total of $750,000 in improving Fountain City Lake.

Additionally, a duck food dispenser has been installed so that patrons have easy access to appropriate food that’s healthy for the waterfowl.

When improper foods like cat food and bread are fed to the waterfowl, an overabundance of nutrients forms in the water, which then feeds unwanted rapidly growing algae. Food unfit for ducks and geese also leads to obese conditions and weakened, malnourished bones. This can sometimes lead to angel wing syndrome, causing an inability for the birds to fly.

“The moral of the story is that it’s going to take a community-wide effort for Fountain City Lake to truly thrive,” said Hagerman.

Now that the native plants have been installed in the wetlands, the water will be raised back to normal level.

Click HERE for a Frequently Asked Questions fact sheet about the wetlands project.

Posted by On 07 December, 2018 at 1:28 PM