Clue to water main break elusive after seven weeks
WESTON — The detective work continues. So far, no good.
With the spending meter at $137,000 and counting, state officials still have not found a 1,200-pound, 31-foot steel coupling that could show why 2 million people in Greater Boston suddenly lost their drinking water May 1.
In the layman’s mind, the search might seem like finding an elephant in a haystack. But to the engineers, excavators, and executives who continue to comb the site where the coupling burst on the region’s main water line, the stubborn reality has become a long-running, frustrating mystery.
“It’s a little bit embarrassing,’’ said Frederick A. Laskey, executive director of the Massachusetts Water Resources Authority. “People don’t understand how we could get that pipe fixed so fast, and this is taking so long.’’
The search has yielded a few tantalizing nuggets of evidence: a small sealing plate, an O-ring, and a single bolt that possibly comes from the collar. But the coupling itself, two pieces of metal that had joined a pair of massive steel pipes for seven years, re mains elusively at large.
“It’s kind of taken on a life of its own,’’ Laskey said Thursday at the work site. “Everywhere I go, people say, ‘The MWRA did a great job fixing the pipe. Did you find the collar?’ ’’
Finding the coupling is considered critical to determining why the water main burst, who is responsible for the failure, and whether other parts of the water-delivery system are vulnerable. The bolt, for example, is believed to have been rusted when it broke, Laskey said.
In Weston, the search slogs on. So far, a 20-foot-deep pit has been dug on the south side of the pipeline, the nearby Charles River has been scoured by State Police divers, more than 600 tons of soil have been sifted, and ground-penetrating radar has scanned the area for buried evidence.
The yield: next to nothing.
“Is it in one piece, is it two pieces, or is it many pieces?’’ said Michael Hornbrook, chief operating officer for the MWRA. When asked whether this disappearing act boggles the mind, Hornbrook smiled and replied, “Yes, yes, and yes.’’
Although the coupling is a formidable piece of metal, intense water pressure is more than its match. “Do not underestimate the force of that water,’’ said Kathy Murtagh, a geotechnical engineer and vice president at Camp Dresser & McKee, which is working on the project for the MWRA.
When the coupling separated, a 1-inch gap between two 10-foot-diameter pipes was enough to send millions of gallons of water gushing from the broken line with enormous power. Under one scenario, the clamp could have skidded 100 yards toward the Charles River on a fast-moving carpet of raging water.
Divers, however, found nothing in the river near the junction of the Massachusetts Turnpike and Route 128. Likewise, 800 cubic yards of soil carried into the Charles contained no evidence of the clamp. The O-ring and bolt were discovered within a day of the break; the sealing plate was recovered Wednesday.
On June 11, excavation stopped in the south pit because of concerns over weak, shifting soil that might endanger the stability of the pipeline. But beginning this week, small borings are expected to probe two “hot spots’’ in the pit that have been identified by ground-penetrating radar.
“Let’s hope we hear clink, clink,’’ Murtagh said.
If the coupling is not found, excavation will be considered for the north side of the pipe. That work also carries risks, so MWRA officials said they are working methodically to avoid another accidental disruption to Greater Boston’s water supply.
For three days after the rupture, residents in much of Boston and 29 surrounding communities were ordered to boil their water before drinking, cooking, and even brushing their teeth.
“There’s this huge third rail here that we need to guard and protect,’’ Laskey said. “It’s a frustrating situation, but we don’t want to let our frustration cause us to make mistakes and come back to haunt us.’’
Laskey said he is determined to press ahead at a careful pace, but he will not rule out the possibility that the hunt will end if the search continues to come up empty. “We’ll cross that bridge when we come to it,’’ Laskey said.
One reason for the search is to determine possible liability for the break, or “cost recovery,’’ as Laskey said.
The MWRA has not yet paid the Barletta Companies, which installed the clamp, for its work in the frantic repair effort, which cost more than $300,000.
Laskey would not comment on why the MWRA has declined so far to pay Barletta.
Without the coupling, the work of an independent panel investigating the rupture will be made more difficult. The makeup of that three-member panel, to be headed by Wentworth Institute of Technology president Zorica Pantic, will be announced soon, Laskey said.
In the interim, the water-break site remains a busy place, although soil-grading and plantings have smoothed and improved much of the area.
Somewhere in that space, engineers said, the remains of a coupling are hidden. But exactly where remains the great, unanswered question.
“We’re just going to keep pounding at this,’’ Laskey said. “We’ll get it.’’
Brian MacQuarrie can be reached at macquarrie@globe.