Nolin River Lake pilots new reef balls for fish habitat

U.S. Army Corps of Engineers, Louisville District
Published Oct. 5, 2020

As part of a multi-agency effort, Nolin River Lake will be the first in the Louisville District to install concrete reef balls in the lake to serve as fish habitat.  

The collaboration is part of a larger effort with Kentucky Fish & Wildlife, Friends of Nolin, Friends of Reservoirs, Roundstone Native Seed LLC, Fishiding Reclaimed Artificial Fish Habitat, Moutardier Marina, Atmos Energy Cooperation, and Reef Innovations, to complete a $300,000 bank stabilization project, which includes installing rip rap to promote bank stabilization, planting native terrestrial plants to promote the pollinator initiative and enhancing fish habitat, said Nolin River Lake Park Ranger Libby Watt.

Watt, who is driving this environmental stewardship effort for USACE, said the concept of using reef balls as fish habitat came about due to a strong partnership with the Kentucky Department of Fish & Wildlife Resources. 

“They offered to collaborate on this project and helped secure a grant from Reservoir Fish Habitat Partnership (RFHP), a non-profit group who works to improve fish habitat in different areas for government agencies.”

“We received a grant through RFHP for $30,000,” Watt said. That grant paid for eight fiberglass reef ball molds and all the supplies and equipment to make them.

“It’s a patented design that is only to be used in lakes in Kentucky based on our agreement with the Reef Innovations, the manufacturer of the molds,” Watt said. “They came here Sept. 28 – Oct. 1 and trained staff from the Department of Fish and Wildlife and USACE Green River Area employees on how to make and install them properly.”

Watt says the No Shoes Reefs initiative, started by country music star Kenny Chesney, also donated one large fiberglass mold so the team could produce as many reef balls as possible. 

“Our immediate goal is to make 48 reef balls to put in the water early next spring.  We were able to make 18 reef balls during our training day, so over the coming weeks our team will finish pouring the rest of the them,” Watt said.

The reef balls specifically target bass, crappie and catfish. Three sizes were purchased for this effort to include pallet ball, bay ball and mini bay balls that range from 4 feet by 2 feet wide and weigh between 200 – 600 pounds. 

Watt noted that there are additives in the concrete that protect the concrete from leaching calcium under water and protect them from freeze and thaw effects if exposed from winter pool drawdown. It makes them ideal for fisheries management at reservoirs, where the water depth may fluctuate up to 25 feet between summer pool and winter pool.

While the reef balls are primarily intended as fish habitat, USACE also plans to experiment with using the larger ones as wave breaks to further protect the shoreline.  “The reef balls have been used extensively in marine habitats for fish habitat, to promote coral reef growth, and as shoreline and beach protection, but haven’t been used much at all in freshwater systems,” stated Watt. “We’re excited to see how the reef balls will affect shoreline erosion in our reservoirs.” 

“We’re working to reduce erosion with the bank stabilization effort and enhancing aquatic habitat, while also developing relationships with our partners and stakeholders. It’s a win-win,” Watt said.