Beneath New York’s vast streetscape is an underground labyrinth of water mains that are essential to the city’s day-to-day existence. But sometimes those pipes can burst without warning and wreak havoc.
Many are decades old, and not aging well.
On Thursday, one particularly senescent water main — dating to before World War I — ruptured, flooding a major highway in the Bronx, trapping drivers in their cars, snarling traffic on the George Washington Bridge and submerging the surrounding streets.
The rapidly rising waters sluiced onto the Cross Bronx Expressway from above, officials said, stranding eight people around 3 o’clock on a cold morning until emergency workers came to their rescue. Seven vehicles were abandoned, some appearing to poke through the water’s surface like bath toys.
The cause of the break, on Jerome Avenue near 175th Street, was not immediately clear, a Fire Department spokesman said, but the rupture highlighted the brittle state of the city’s subterranean infrastructure.
The city’s Department of Environmental Protection had managed to shut off the gushing water by 6 a.m., an agency spokesman, Ted Timbers, said.
“Water obviously drains to the lowest point,” Mr. Timbers said. “The lowest point happened to be a few blocks away, at the Cross Bronx Expressway underpass.”
The department would conduct a forensic investigation on the pipe to try to figure out what caused it to burst, he said.
Dozens of city workers were repairing the damage, which could take days, he said. The break flooded the basements of 10 buildings, and Mr. Timbers said anyone whose property was damaged could file a claim with the city comptroller’s office.
New York City pumps about a billion gallons of water per day through 7,000 miles of water mains whose average age is nearly 70 years. The city spends hundreds of millions every year on repairs and has embarked on an effort to replace mains and other underground infrastructure.
The 48-inch-wide, cast-iron water main that ruptured on Thursday was installed in 1909, the year William Howard Taft succeeded Theodore Roosevelt as president.
Still, the pipe’s age alone might not have played a major role in the break, Mr. Timbers said, noting that “age is not the only predictor of performance.” He added that the pipe did not directly supply water to the surrounding buildings, describing the main as a “highway for water” and not a “local street.”
Residences and businesses in the area did not lose water service, he said.
Several high-profile breaks over the past year have closed city streets, snarled traffic, disrupted public transportation and destroyed a beloved movie theater near Lincoln Center.
Just days ago, Off Broadway’s York Theater in Midtown Manhattan was wrecked by flooding and mud from a break.
In recent years, the city has usually had more than 400 water main breaks a year, most of them too small to warrant much attention. They tend to happen more frequently during the winter months, when fluctuating temperatures cause valves and joints to expand and contract, stressing the system.
“The freeze-thaw cycle certainly plays a part in causing breaks,” Vincent Sapienza, the commissioner for the Department of Environmental Protection, told The New York Times in 2020.
The city measures breaks per 100 miles of water main each year, and despite the age of many pipes it outperforms many other cities. Mr. Timbers said the city had averaged just under five breaks per 100 miles so far in fiscal year 2021, compared with a national average of about 25 breaks per 100 miles.
Mr. Timbers said that in fiscal year 2020, which ended on June 30, the city had recorded 347 breaks, the fewest since the city started keeping records.
Early Thursday, the Cross Bronx Expressway — a thoroughfare that before the pandemic was choked with traffic most weekday mornings — was closed in both directions at Jerome Avenue, according to the Police Department. Mr. Timbers said that he thought the water was mostly drained from the highway by about 9 a.m., but that residual delays lingered.
Ansumana Ceesay, the manager of a Dollar Expo store on the northeast corner of Jerome Avenue and 175th Street, said he spent the morning cleaning up and trying to save about $10,000 worth of newly delivered merchandise.
“The store was full of water,” Mr. Ceesay said.