District 5 Councilwoman Cheri Bryant Hamilton and MSD Executive Director Tony Parrott christen the tunnel boring machine “Bumblebee” on Monday. | Photo: Mark R. Long

The Metropolitan Sewer District on Monday said that it bumped up its cost estimate for a big, federally mandated system upgrade by around $40 million, to $980 million, at least the second upward revision from an earlier $850 million projection.

The work is focused on nearly eliminating the combined flow of wastewater and storm runoff into the Ohio River and Beargrass Creek by 2024, in order to meet the terms of an amended “consent decree” agreed with the Environmental Protection Agency in 2008. 

The system revamp includes the digging of a $200 million tunnel to collect storm and wastewater during big rains for later treatment, keeping it out of waterways. MSD on Monday unveiled the cutter head to the giant boring machine — which it christened Bumblebee in honor of Muhammad Ali — that will dig the four-mile tunnel 18 stories under downtown.

“Until you get into detailed design and execution you really don’t know exactly how it’s going to turn out until you bid the projects,” MSD Executive Director Tony Parrott said. He added community feedback prompted design changes of the Logan Street basin, the southwest basin in Shawnee Park and the pump-station building at 12th and Rowan streets. The cost of the tunnel is expected to remain around $200 million.

MSD spokeswoman Sheryl Lauder said some materials costs had gone up, adding the earlier $850 million estimate was based on 2005 data. New modeling technology had given a more accurate view of water flows, expanding the scope of some projects. She said final costs may come in higher or lower than estimated. The consent-decree plan has changed over the years, with MSD in 2016 scrapping the planned construction of some basins in favor of the tunnel.

Map provided by MSD

“When you think about the additional cost though — you look at the changes on this tunnel project for example — over the life of the asset it’s actually cheaper than the original basin project that we had programmed in,” Parrott said.

He added that MSD’s ability to get very low-interest rate loans will help offset some costs.

MSD has been pressing to be allowed to raise rates by maximum 9.9 percent a year — up from the current maximum of 6.9 percent — to pay for rehabbing sewer lines, flood protection, additional wastewater treatment, and other work. So far, Louisville Metro Council hasn’t approved such an increase. Including $500 million of the consent-decree expenses, MSD has estimated it will cost $4.3 billion over 20 years to complete all necessary repairs and upgrades.

“The big part of the critical repair plan that we’re asking for the rate increase (for) is more associated with work on other assets outside the consent decree, whether it be stormwater or drainage, or whether it be our flood-protection system,” Parrott said.