By John Brewer
The St. Paul Pioneer Press
ST. PAUL, Minn. — A man was swallowed by a sinkhole Tuesday morning in downtown St. Paul after a leaking water line to an office tower eroded the ground under his feet.
David Wayne Clark, 55, of St. Paul “was banged up pretty bad” after the area near a bus stop at the southeast corner of Sixth and Wabasha streets collapsed beneath his feet about 9:15 a.m., St. Paul Fire Marshal Steve Zaccard said.
Clark suffered bumps and bruises as paving bricks from the sidewalk tumbled onto him, Zaccard said.
The leak was in a service line from the water main to Ecolab, said Steve Schneider, general manager for St. Paul Regional Water Services. He said the main was in a tunnel bored out of the sandstone beneath downtown in the early 1900s.
He had no idea how long the service line had been leaking, but by the time the sidewalk collapsed, water had washed away enough soil to leave a hole 20 feet long, 8 feet wide and at least 15 feet deep. A police official said that by the time the water was shut off, the hole was an estimated 30 feet deep.
Much of the water and the soil were washed through the tunnel and down to the storm sewer system at Cedar Street. The sewer system was not damaged.
City crews shut off the leak within a couple hours of the collapse and determined the leak was an isolated event.
“The sidewalks are safe here,” said Shannon Tyree, spokeswoman for the city’s Public Works Department.
Sixth Street and Wabasha were closed temporarily; both reopened by evening.
Ecolab lost water service, but crews were working to restore it with a temporary water supply.
The city planned to shore up the hole so workers could get to the broken pipe and assess damage.
Schneider said the water line could be repaired overnight, but he said the sidewalk would take a couple of days to fix.
The water main adjacent to Ecolab runs through part of a 2- to 2 1/2-mile tunnel system for water pipes in the upper section of downtown. The actual main, a cast-iron pipe, was installed in 1971.
“That’s not old for water mains,” Schneider said.
The city has 1,100 miles of water mains, Schneider said, and typically sees 150 to 200 water main breaks a year. The breaks usually happen in winter when cold weather causes soil to expand and burst the pipes.
The water lines running through the sandstone tunnels beneath downtown “typically serve us very well,” Schneider said, as the tunnels maintain a constant temperature in the mid-50s.
He said city workers walk the tunnels each winter to inspect the pipes and didn’t see any problems last winter.
The last call to the area for water problems was in 2006, when Ecolab had water pooling in the basement of the building. Schneider said the water was determined not to be from the city water supply but rather some other source.
Clark, the injured man, was either walking along the sidewalk or waiting for a bus, which arrived shortly after the collapse, according to various accounts. One police officer on the scene said it was the bus driver who first called 911.
A smaller sinkhole formed earlier this month near Como Park from a broken or leaking sewer line, city officials have said.
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