The Great Lakes Water Authority has started building a new tunnel in southwest Detroit. The project will divert excess stormwater from a large sewer line along the Rouge River to a retention and treatment basin nearby.

Potential to address a longstanding problem

GLWA Chief Operating Officer Navid Mehram says the tunnel will reduce the risk of flooding. Additionally, it should mean fewer basement sewage backups during heavy rain. “We’re making an investment in our existing system by rerouting some flows, so that we can leverage an existing facility that wasn’t receiving all the flow it can treat,” Mehram says.

The tunnel will be almost 4,000 feet long and several feet wide. Nehram says GLWA expects to finish the job in 2028. “Our projects are very large,” he says. “This is a tunneling project, which is extremely complicated.” Besides reducing sewage backups, Mehram says the project will also make the system more resilient to heavy rain. “This not only provides us with water quality improvements along the Rouge River, but it can also provide a backup for our Water Resource Recovery Facility,” he says.

Who’s paying for it?

The project will cost $87 million. Mehram says GLWA will use both government grants and sewer rate revenues to pay for it. He says it will not increase customers’ bills.