Art Shapiro was motoring south on Eutaw in his maintenance truck when the call came across his radio: Head to Lombard and Light streets, where a water leak needed attention.
Baltimore's chief of utilities maintenance figured the call, around rush hour Monday, was for just another of the dozens of ruptures he and his crew of nearly 500 deal with every day in their effort to keep the city's complex and aging water-delivery system running.
As he rounded a corner, though, he saw snarled traffic, police tape and a sure sign he was dealing with something bigger — a gash in an artery that supplies much of downtown. The repair would be complicated by the power, gas and telecommunications lines buried nearby.
"I was watching [a] river go downhill," he said.
As commuters know by now, a break in the water main running below Light Street between Redwood and Lombard flooded the streets and created a traffic nightmare.
The block will be closed for up to three weeks, city officials say, as a crew from Spiniello Infrastructure Worldwide, a private contractor, makes repairs.
On a 100-degree afternoon this week, as a dozen or so workers used shovels, excavators and backhoes to expose the ruined pipe, the work offered a glimpse into the workings of the byzantine infrastructure that feeds the city's main service area, 560 square miles in Baltimore and in parts of Howard, Anne Arundel and Baltimore counties.
Water mains — pipes usually between 3 inches and 12 feet in diameter — are so important that when one like the 20-incher below Light Street ruptures, residents see the results right away and the city must swing into action.
The flow, though, starts miles away.
Baltimore's main sources of water are the Gunpowder River and the North Branch of the Patapsco, says Kurt Kocher, a spokesman for the city's Public Works Department. Dams entrap that water in the Prettyboy, Loch Raven or Liberty reservoirs.
From there, huge pipelines carry it to any of three filtration plants — Ashburton in Northwest Baltimore or either of the two Montebello sites to the east — where engineers remove sediment and chlorinate the water, sending it to tanks and reservoirs for storage. Then water pressure drives it through 4,500 miles of pipes and ultimately to 1.8 million users.
In one way, Shapiro says, the city was lucky. Water pressure is created in one of two ways: by pumps in places where water must be directed uphill, or by gravity when it's moving from a higher elevation to a lower one.
The Light Street pipe is part of a line that runs from Montebello toward the Inner Harbor, a downward path the whole way.
"If that were a pumped line, the flooding and disruption would have been much worse," said Shapiro, who compares a pumped line to a major artery in the body, a gravity line to a vein.
It was bad enough as it was. Once his team closed off the ends of the pipe, Shapiro says, technicians at Montebello had to increase the flow by 410,000 gallons an hour to restore normal water pressure through the system.
"It will be a while before we can calculate how many gallons were lost," he said.
No one can say when the leak under Light Street started — it could have been months ago — but it only appeared after water saturated the gravel-and-sand roadbed, then pierced the street's 14 inches of asphalt. The street collapsed in front of the 7-Eleven on the west side of the street, 25 feet from the pipe in which the leak was ultimately found.
That alone indicates that the leak was probably from the bottom of the 123-year-old cast-iron pipe, said Kenneth Morgan, deputy water services director for Phoenix, Ariz., and author of the "Managing Water Main Breaks Field Guide."
If a leak or rupture is more narrowly confined, it can often be fixed in eight hours, Morgan says, often by placing a sleeve around the break. A failure of this nature, though, calls for major excavation done in coordination with other utility providers, includingBaltimore Gas and Electric Co., and replacement of whole sections of pipe.
Shapiro's maintenance team spends the vast majority of its time dealing with smaller-scale problems, usually dozens at a time — no surprise, given that many sections of the system are 75 to 150 years old. Such work often involves locating leaks and shutting off or replacing valves.
Because the teams must remain mobile and be able to work in small spaces, the city owns mostly smaller equipment like so-called mini-excavators. "We have to stay light on our feet," Shapiro said.
For the relatively infrequent bigger jobs, the city hires on-call contractors such as Spiniello, an international company that has an office on East Biddle Street. The contractor's heavier gear was on display Wednesday afternoon and Thursday morning.
A yellow backhoe straddled a trench the men had dug, a scar in the pavement 3 feet across and 7 feet deep. The chasm ran up the center of Light Street for half a block. A dump truck stood nearby, filled with excavated gravel and sand, another one a few feet away, its bed loaded with fresh white gravel.
A new, 20-foot length of ductile-iron pipe — a more flexible, durable material than the original — lay beside the trench, apparently ready to be installed.
Crewmen and supervisors would not comment, but Shapiro said the plan was to start at the southern end of the trench and work uphill, laying one length of pipe at a time. They will pack the roadbed around each section, then have city workers pave it, before moving on, then continue in this fashion, 700 feet or so up the street, until work on the 20-inch main is complete.
Morgan says the approach makes sense. If you start at the higher end and work down, he says, by the time you get to the bottom, gravity will have thrown off the alignment of the pipes. Work bottom to top, however, and by the time you reach the end, you'll be able to link up old pipe and new without much trouble — and be able to restore the water network to full operation, which is the main goal.
"This kind of repair work isn't simple," he said. "It helps to know a few tricks of the trade."