A giant drill driven by six 300-horsepower motors and using enough daily electricity to power 382 homes is digging a tunnel under Louisville. The machine is massive, and it’s part of a $200 million Metropolitan Sewer District project that is aimed at reducing the amount of sewage dumped into the Ohio River during heavy rainfall and avoiding fines from federal regulators.
The tunnel is meant to hold Louisville’s excess storm and wastewater. During dry weather, that water is treated at Louisville’s water treatment plant before it’s released into waterways, but heavy rainfall can swamp the facility and force MSD to dump untreated sewage water into Beargrass Creek and the Ohio River. The Waterway Protection Tunnel — one of many projects designed to reduce these sewer overflows — will stretch four miles under Louisville and measures 22 feet in diameter. When it’s done, it will hold up to 55 million gallons of overflow waste water until the water treatment plant is ready for the water.