Monday morning's commuters found a section of Bismarck Expressway between Second and Third streets closed off as Markwed Excavation was on site to repair a water main break.

The 24-inch water main broke sometime Sunday morning, according to Keith Demke, city director of utility operations. It took crews until mid-Sunday afternoon to get the section of pipeline isolated and shut down.

A combination of valves - old valves - had to be worked back and forth before the shutoffs were seated, according to Demke. By the time the pipeline was shut down, it was too late to do any work on it. On Monday, Markwed had to dig a 9-foot ditch across Expressway to get to the pipe.

"They found the spot where the problem is, put a sleeve over it and thought they had it fixed. But when they pressured it back up, it still leaked," Demke said.

"Today (Tuesday) they cut out the section of pipe which they have to replace. We're thinking it will be done later in the afternoon, but it is hard to say. It will probably be (today) before they can get it covered back up and have a driving surface to allow traffic go through."

There were some adjacent businesses that were closed for a while early in the process, Demke said. Two adjacent hotels were without water part of Sunday, but temporary service was provided by Sunday evening. Perkins restaurant was closed Monday, but reopened Tuesday with temporary service.

A couple of apartment buildings and a few businesses were out of water for just a short time before temporary service was in place.

Demke said the line is a major transmission line that moves water across town and doesn't provide much direct service. Several areas may have noticed water pressure go down, but there are enough water lines that water was always available.

"This is a major artery, but water can take other routes," Demke said. "We really don't know what caused it yet and won't know until we can inspect the portion of pipe that is cut out. We'll have to see if it is corroded or cracked."

The water main is made of ductile iron, which was the popular choice of water lines after the mid-1950s, Demke said. He said he believes this line was put in place in the early 1960s.

"We did find a round hole in it. Sometimes this indicates that it was tested for pressure. Often, they put a plug in afterwards, and over time, it may have blown out," Demke said. "We kind've thought that was it. But a repair sleeve should have fixed it and it didn't. There may be a crack or corrosion pits. We'll never know until we get it out."

(Reach reporter Gordon Weixel at 250-8255 or gordon.weixel@bismarcktribune.com.)