The collapse of a regional sewer line Friday on St. Paul’s East Side left a large sinkhole near a busy intersection, requiring repairs that could take several days and tie up local traffic in the meantime.
However, no one was hurt and there were no reports of sewage problems in nearby homes, officials said. By late Friday afternoon, crews were busy diverting the sewer to a temporary above-ground polyethylene line so they could fix the broken concrete pipe.
The break occurred about 2 a.m. Friday on the boulevard in the east corner of Phalen Boulevard and Johnson Parkway, said Tim O’Donnell, a spokesman for Metropolitan Council Environmental Services.
The line that failed is a 54-inch gravity-flow concrete pipe laid in 1989 that collects sewage from as far as Forest Lake and directs it to the Met Council’s Metropolitan wastewater treatment plant on the Mississippi River in St. Paul, the largest plant in the state.
Although it was unclear what caused the break, it appeared that the top of the pipe had corroded and collapsed under the weight of the waterlogged earth above it, O’Donnell said. Most of the pipe, which handles an average of 12 million gallons of sewage daily, was still intact.
The result was a crater about 25 feet deep and measuring 25 feet across. St. Paul Public Works detoured traffic away from the site as emergency contractors got to work.
Line breaks this size “are pretty rare,” O’Donnell said. “We tend to have smaller breaks in the system every two or three years. A break this large happens every 10 years.”