(Photos/Nancy Hanson.)

Construction crews have spent the summer refurbishing the city’s 90-year-old brick sewers with smooth, tough fiberglass liners. But while much of the action is 25 feet underground, where robotic equipment has been deep-cleaning and mapping the interior of the old hand-built lines, traffic has still been slowed to a single lane in each direction.

Traffic engineer Jonathan Atkins notes that the city has made every effort to avoid extended closures around the 10 city blocks along Main and Center avenues involved in the final year of the three-year relining project. Some intersections have been closed temporarily to install new, larger manholes — a necessity for the upcoming installation of the custom-made sock-like liners, which will ultimately be heat-cured into rigid, durable piping. 

Liner installation is expected to begin next week on Eighth Street from Main to First Avenue North. Atkins estimates a three-week impact on traffic.

One major bump in the road, so to speak, lies ahead in September. Atkins explains that repairs to a section of sewer that failed some 40 years ago will require opening up Main between Sixth and Seventh streets.

“The solution back then involved installing a new line inside the bricks,” he explains. That worked, but it’s not compatible with the liner system now being put in place. The 1980s pipe is round, with a diameter of 40 inches. The original brick sewer is oval, with a 46-inch diameter. “We’ll need to make an open cut to take out that section so the seamless liner can be installed without wrinkles or obstructions,” he explains.

The closure is expected to be relatively brief. Since surrounding sections will be completed by then, a short bypass will be put in place while the street is opened.