Knoxville City Council on Tuesday unanimously authorized a $249,000 contract to construct two small wetlands on the edges of Fountain City Lake – the final step in the City’s long-range plan to upgrade the lake’s infrastructure and improve its water quality.

Once a contract is finalized with Savannah, Tenn.-based Ronald Franks Construction Co., the wetlands will be built over about four months. The project is anticipated to be completed by late fall 2017.

One small wetland will be constructed on a western patch of the lake, and a larger wetland will be built on the northeastern edge. Each wetland will be strategically placed to eliminate shallow, stagnant zones of water that for years have encouraged the growth of thick algae. The wetlands will total less than a fifth of the 1.1-acre lake. 

Each constructed wetland will incorporate a gabion, rip rap stone base and gravel filtration layer, topped with native wetland plants.

The design will discourage algae growth three ways:

• The deeper lake will allow less sunlight to penetrate the water to the floor; both the depth and the lake’s cooler temperatures make it less conducive for algae to form;
• The lake’s water will circulate better, flowing from springs on the northwestern end to the outlet across the lake, without the two stagnant zones where water doesn’t churn; and
• The new aquatic plants will suck up nutrients in the water – mostly from waterfowl feces – that now accelerate algae growth.

The wetlands construction is the last major step in a three-year series of infrastructure investments, totaling about $500,000, made by the City.

Previously, the City and its contractors have repaired a leak in the earthen berm that surrounds the lake, allowing the water to deepen to healthy levels. Crews have repeatedly drained, cleaned and treated the lake, and inappropriate species of fish have been relocated. Algaecide has been sparingly added. Last year, work was completed on the lake’s fountain system and pumphouse to increase aeration, which helps control algae growth by adding oxygen to the water, agitating the water and reducing stagnation.

“The creation of these wetlands is a major step in continuing the restoration of the lake,” said Joe Walsh, the City’s Director of Parks and Recreation.

“We knew returning the lake’s water quality to good health would be a long process, but it’s nearing completion. The wetlands will create new habitat for wildlife, and they will complement the lake’s beauty.”

Even after the infrastructure improvements are finished, the City will continue to support the Lions Club’s management of the property, which is owned by a private non-profit organization. 

Earlier this week, repairs to the outlet structure required the lake to be drained. The water will be lowered again this summer and fall, when the wetland construction gets underway.

Walsh reminds Fountain City Lake visitors that feeding the wrong food to the lake’s ducks and geese is harmful – both to the ducks and to the water quality. Visitors often bring bread, grain or pet food from home to feed the ducks. Visitors are discouraged from feeding the ducks, but if they do feed the ducks, they should only give them the food pellets available at lakeside dispensers.