Environment

More than 18 stories beneath downtown Louisville, construction has nearly finished on a $212 million project that most people will never see.  

Louisville’s Metropolitan Sewer District calls it the Waterway Protection Tunnel, and last week it reached a major milestone: construction crews completed the concrete liner on the four-mile-long pipe, which stretches from 11th Street and Rowan Street on the west side of downtown all the way to the intersection of Lexington Road and Grinstead Drive near Cherokee Park.

The tunnel is 20 feet in diameter: large enough for three people to stand on each other’s shoulders and maybe touch the top. It’s capable of holding 55 million gallons at one time, enough to fill 83 Olympic swimming pools.   

Now imagine that tunnel full of sewage and storm water. 

Ryan Van Velzer | wfpl.org

The tunnel addresses a major problem in Louisville: Basically since the city’s founding, we’ve been dumping raw sewage into Beargrass Creek and the Ohio River. Prior to 1958, they straight-piped feces into these waterways. 

Even now, when it rains, the city’s sewers often become overwhelmed with storm water and sewage that then flows into those bodies of water. Under a federal consent decree with the Environmental Protection Agency, MSD has spent nearly a billion dollars to manage this deluge and the tunnel project is a capstone. 

MSD’s Chief Operations Officer Brian Bingham said the tunnel will capture about 92% of the sewage and storm water overflows. From there, it’s pumped back to the state’s largest water quality treatment center over in the West End where it’s treated and sent into the Ohio River. 

“We looked at that and we were originally shooting for 95% but it just became so cost prohibitive to get that last little bit. We determined it was better to spend that on other community projects,” Bingham said, standing inside the tunnel. 

The tunnel is roughly a year behind schedule and about 12 million dollars over its 200 million dollar budget. Project Manager Jacob Mathis said that’s pretty good compared to projects similar in scope.

“You do hear some tunnel projects are hundreds of millions of dollars over budget and 10 or 20 years behind schedule,” Mathis said. 

Ryan Van Velzer | wfpl.org

With the concrete liner complete, Mathis said the project is about 98% complete. Construction crews just need to add a few finishing touches inside the tunnel and complete the surface structures where sewage and storm water flow into the tunnel. 

The tunnel is set to begin operating in June and though most won’t ever see the tunnel itself, Bingham said residents will see the results: cleaner waterways that are better for the public and the environment. 

“This is pretty phenomenal when you look at it and imagine it, nobody will see this again, but it will, year after year, do a tremendous job of helping us make our community better,” he said.

This story has been updated. 

Ryan Van Velzer is WFPL's Energy and Environment Reporter.