Waterway Protection Tunnel passes midway point

February 6, 2020

Bumblebee—the machine boring MSD’s Waterway Protection Tunnel—has reached the halfway mark in her quest to carve a 4-mile path through bedrock eighteen stories under Louisville. Named in honor of Muhammad Ali, the 412-foot long machine is under the area of Franklin and Buchannan streets. Soon, she will turn southeast and head toward the final destination of Lexington Road and Grinstead Drive.

 “Bumblebee has excavated approximately 10,909 linear feet of 20,205 linear feet of the main tunnel as of February 3,” said Project Manager Jacob Mathis. He expects tunnel boring to be complete by August 2020.

How does Bumblebee work?

As the boring machine excavates the tunnel route, crews install locomotive tracks behind the machine to transport workers and supplies. A conveyor system transports the excavated rock through the tunnel to the working shaft. There it rides a vertical conveyor to the surface. The rock is then loaded into dump trucks and transported to a local quarry.

After the excavation is complete, the entire length of the tunnel is lined in concrete, making it watertight. The Waterway Protection Tunnel will store up to 55 million gallons of combined wastewater and stormwater during periods of heavy rain until capacity is available in the MSD sewer system. The contents are then pumped back into the system, conveyed to MSD’s Morris Forman Water Quality Treatment Center for proper treatment, and later released into the Ohio River.

“Tunnel boring projects are wonders of engineering and technology, and we are excited to bring this innovative solution to Louisville to help create safe and clean waterways,” said MSD Executive Director Tony Parrott.