MSD starts digging massive tunnel 18 stories underground

LOUISVILLE, Ky. (WDRB) -- MSD hit a milestone in its three-year Waterway Protection Tunnel project Tuesday when crews finished digging a 230-feet deep shaft, which they'll use to access equipment and drill the four-mile tunnel.

The tunnel is designed to prevent wastewater and stormwater from overflowing into Beargrass Creek and the Ohio River. When it rains in Louisville, the system can get overwhelmed and spill sewage into local waterways.

“It takes no more than one tenth of an inch of rain to overflow to Beargrass Creek or the Ohio River,” said Jacob Mathis, an MSD engineer. “So this project will allow us to capture that flow and protect the waterways.”

It’s a problem many cities across the country are experiencing with antiquated sewer systems. So the federal government issued a consent decree, which is based on the Clean Water Act of 1972. Louisville must meet the federal requirements by 2020.

 The Waterway Protection Tunnel is expected to exceed the requirements by creating more overflow storage space than originally planned. The first design was for a tunnel 2.5 miles long, but MSD decided to add another 1.5 miles. So it will start with the pump station at 12th and Rowan Streets and extend to the intersection of Lexington Road and Grinstead Drive.

In a typical year, 439 million gallons of sewage and rainwater enter our waterways. An MSD spokesperson said the tunnel will capture and treat 98 percent of the combined overflow. This tunnel will have a maximum capacity of nearly 55 million gallons of wastewater and stormwater. That’s the equivalent of 83 Olympic-size pools.

“We are working on a daily basis to make our community a safer and healthier place, for not only ourselves but future generations,” Mathis said. 

The next step will include blasting 500 feet into the ground to start building the tunnel. Crews need this much space in order to assemble the machine that will continue digging the rest of the four miles.

Project leaders said the pieces of the machine will be delivered sometime this fall. It will need to be built on site before it can start digging.

The entire $200 million project is expected to be finished by the end of 2020.

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