WILLMAR -- Quam Construction of Willmar was called by Willmar Municipal Utilities today to repair a break in a 12-inch water main on Fourth Street Southwest between Minnesota Avenue and Monongalia Avenue Southwest.
It was one of two water line breaks that happened Monday night or early today.
Bart Murphy, superintendent of the utility's water and district heating department, says he believes external corrosion from the soil, and possibly frost action, caused the break in the ductile iron pipe, which was installed in 1977 under Fourth Street.
Murphy said corrosion is not atypical in Willmar.
"There are areas where we see external corrosion on iron pipes causing failures in the roughly 25- to 35-year period,'' he said. "It takes that long. We've seen it over and over again. There are certain areas in Willmar where ground conditions cause that corrosion.''
The hole could range in size from golf ball to a fist. "We've seen that in the past,'' said Murphy. He said the break will be repaired today "unless we get into something really unusual.''
The other break occurred in a 4-inch water main at Monongalia Avenue and Bonham Boulevard Southwest. Murphy said that break will not be repaired until the 12-inch main is repaired.
Murphy believes frost action caused the break in the 4-inch main.
"We always have water main breaks in the winter when the frost goes down, and in a 'normal' winter, the breaks start happening the last couple of weeks in December because we believe that's when the frost gets down to a level where it starts exerting forces in the ground that change ground pressures and find weak spots,'' said Murphy.
"This year we had a very mild stretch from mid-December till last week and now it's getting a little colder and the frost is starting to move down. Things are starting to happen. That's pretty normal,'' he said.