New London — Work began Friday to repair the broken water line that hemorrhaged 8,000 gallons per minute Thursday and threatened the water supply for both New London and Waterford, but crews still have not yet been able to access the pipe itself.

On Friday, crews from New London Public Works and Veolia, the water company that New London uses, were at the scene of the leak, which is off a trail inside Bates Woods Park.

New London Public Utilities Director Joseph Lanzafame said crews have reduced water flow through the broken pipe to just a trickle but have to wait for the area to drain before bringing in an excavator to unearth the defective pipe. “We pretty much have a full shutdown at this point, (water flow is) very, very slow and we’re thinking that it’s just the pipe draining,” he said. “We’re going to have to wait a few days for that area to dry out before we get in there, but we have a strategic plan to get it fixed over the next week.”

Once the soil around the leak is more stable, crews will be able to access the pipe, which is buried about 8 feet underground, and examine it more closely to try to determine a cause.

“We’re going to dig down so we can find the spot on the pipe that is a problem, pinpoint it and take care of the leak,” Lanzafame said. “Then we’ll cut out the broken section and replace it.”

The pipe that burst is a 20-inch transmission line, likely made of cast iron and more than 50 years old. It is one of several that feeds the city’s distribution system, according to Lanzafame.

The mayor’s office said the city does not yet have an estimated cost for Thursday’s response and the ongoing repairs.

On Thursday afternoon, water could be seen bubbling from underground, creating a 10- by 20-foot pond that was about 3 feet deep. The water flowed away into a marshy area of Bates Woods Park.

Though the city does not have an estimate as to just how much water was lost Thursday, Lanzafame said it was leaking at a rate of 8,000 gallons per minute for at least 12 hours. Based on those figures, the water system discharged at least 5.7 million gallons of water.

Because the leak occurred in a remote, swampy area and not along a roadway or in a neighborhood, there was no concern about possible flooding or road washout. But it also meant that crews had to hunt to find the source of the leak.

Lanzafame said Thursday that had it taken an hour or an hour and a half longer to locate the break, the city would have faced “a major catastrophe.”

“Residents and businesses throughout New London would have been without clean water for the next month,” he said Thursday in a prepared statement.

“If you run out of water in a system, the tanks drain down and people don’t have any pressure. Areas of higher elevation would completely lose pressure and draw a vacuum,” Lanzafame said. “When you start to draw a vacuum, you’re in trouble.”

Had the pressure of the city’s water system dropped below the pressure of the plumbing systems it serves, the flow of water could reverse and draw possibly contaminated water back into the city’s water works, Lanzafame said.

“You don’t know what kind of contaminants you’re drawing into the system,” he said. “When that kind of thing happens, you’re chlorinating for months, you have to flush the whole system, you’re wasting an awful lot of water and it’s very difficult to get the system back to normal.”

c.young@theday.com

Twitter: @ColinAYoung