Construction of a sanitary sewer bypass has complicated travel on Sixth Street South this summer.

city council

Nancy Edmonds Hanson

The dry summer weather has been ideal for street construction projects across the city, assistant city engineer Tom Trowbridge told the Moorhead City Council Monday. Despite complicated plans in which street work is often entangled with simultaneous replacement of city sewer and water lines and natural gas pipelines, six of the seven projects now underway are mostly on schedule for completion by their final target dates at the end of September.

Trowbridge detailed progress on each of the undertakings, ranging from applying a final “wearing course” on streets and avenues in three newer housing developments on the south side to replacing brick-lined sewers around downtown. He also addressed the four-year-long railroad underpass on SE Main, 20th and 21st Streets – now expected to open in the late spring or early summer of 2022.

The sanitary sewer replacement between Center Avenue downtown and Third Avenue South has presented the greatest challenge, Trowbridge said. It dates back to the 1930s and 1940s, when brick-lined sewer mains were constructed by hand. “It was a good design,” the engineer explained, “but when it does fail, it goes fast.”

The tubular tunnels, tall enough for a man to stand, are being replaced section by section with a liner (“like a very big fire hose”) manufactured to fit. Once in place, the liner in installed when temperatures are cool; it is impregnated with resin, inflated and, finally, left to cure. Then openings are cut to connect with other underground lines.

Working within the sewers underground sidesteps much of the above-ground construction that a more traditional method would require – including opening up the street to a depth of 25 feet. However, it still requires bypass pumps and piping at street level. Trowbridge noted that work on 10th Street has been completed; the areas on Sixth Street from Main to Fourth Avenue and Fourth Street from Sixth to Eighth Avenues is scheduled for Aug. 9-25. The contract for the entire project specifies completion by Dec. 31.

Other street projects have faced their own complications but required less innovation. One is on heavily traveled 30th Avenue South between 14th and 20th Streets. The area from 17th to 20th Streets is nearly done; work is now underway from 14th to 17th Streets. Along with underground work on Xcel Energy’s natural gas and NuStar Energy’s petroleum pipelines, that stretch has been complicated by the need to maintain access to the businesses along the avenue. A temporary gravel bypass was constructed to provide a way for customers to get in and out.

Like most other projects, this one is expected to be substantially complete by Aug. 31 and wrapped up by Sept. 30 – “barring weather impacts,” Trowbridge added.

Twelfth Avenue South is now open from Fourth to 20th Streets. It cannot be completed all the way to Southeast Main, however, until the BNSF Railway sorts out the rail crossing just east of 20th. Even the ownership of that area, Trowbridge said, is “incredibly complex.” When the right of way was awarded in 1882, it was only half platted. “They didn’t exactly work out all the details,” he added ruefully. “We just about have it. The ball is in BNSF’s court now.”

He predicted that the railroad, which is responsible for the crossing itself, will complete its assignment in 2022 “after the Main/20-21st overpass is done.” The present five rail lines will be reduced to three, along with other grade refinements. The changes will bring it up to Quiet Zone standards, finally eliminating the need for locomotives to blast their horns. When the crossing is finished, city crews will return to wrap up the last stretch of roadway over to Southeast Main.

As for the largest and longest project, the railroad underpass near the high school, he said progress is coming along. Ames Construction has now completed 80% of the work for which it’s responsible. The Otter Tail Valley Railroad is running on the first of the three overpass bridges. The first BNSF bridge is basically in place, and workers are concentrating on the last one. “We expect to see BNSF on their tracks by Oct. 31,” Trowbridge said. “The roads under the bridges will be done “as early in 2022 as crews can get in to do them.”