The town of Manchester, N.H., has been replacing about two miles of aging water pipeline annually in recent years, but municpal crews could not complete their task before a 12-in.-dia water main dating back to 1901 burst. The rupture on Dec. 13 created a street sinkhole that was perilous for one driver.
“A cap blew off the back of a cross on the water main,” before water gushed up on the left side of the subcompact, trapping it on a live gas main, says Guy Chabot, distribution engineer at the Manchester Water Works. “The 110-year-old main broke due to fatigue." The car and its driver were pulled to safety, but 200 ft of roadway collapsed or was undermined, officials say.
Water was shut off to a three-block area for nearly nine hours. By 3 p.m. service was restored and street repairs were completed, Chabot says.
The water main was a cast iron pipe with 100 psi of water, Chabot says. “Back in 1901, they attached a cap to the cross using metal strapping, but with 110 years of corrosion, the straps blew out,” he adds.
Similar to other old mill towns, “we have pipes as old as 135 years in our downtown,” Chabot says. “We’ve got to keep replacing them for years to come.” He says Manchester has a $1.2-million budget in 2012 for water main replacement as part of its capital program, with priority based on leak history, water quality issues and complaints, then age.
Chabot says the city hopes to double its replacement volume to 4 miles per year over the next 20 years, budget permitting.
