Baltimore Public Works officials - who spent yesterday slogging through a flooded park after a water-main break temporarily cut service to 55,000 customers in the city and Baltimore and Anne Arundel counties - said the cause of the break may be faulty materials.
The 54-inch-wide water main was constructed with pre-stressed concrete, a building material with a spotty performance record, officials said. Although the material has been improved in recent years, earlier batches have proven defective in some cases.
The water main, which is owned by the city but also serves surrounding counties, burst about 8:30 p.m. Saturday. It was made in the mid-1970s, before improvements had been made, said Jay Sakai, chief of the city's water and wastewater division.
"There was a break in this same water main about four or five years ago," he said, adding that the cause of the earlier break could also have been poor construction materials.
Defective pre-stressed concrete may have also been responsible for a break in a 72-inch water main under the Patapsco River in 2002. It cost $2.5 million to fix the water main.
Public Works officials said it was too early to determine the exact cause of Saturday's water-main break, which caused thousands of residents in two counties and sections of the city to lose water service for about four hours late Saturday. The water was back on, although not at full pressure, by about 1 a.m. yesterday, officials said.
"It could be structural, it could be age," said George L. Winfield, director of the city's Public Works Department, referring to the most recent water-main break. "We're not sure."
At the scene of the break yesterday - Willow Grove Park in Lansdowne in Baltimore County - pieces of concrete pipe littered water-soaked sod. A crater the size of a swimming pool and filled with brown water was the location of the break, Winfield said. Along the edge of the crater, two pumps removed water. A backhoe was stationed nearby for use once the water had been removed.
Winfield said it could take two days to fix the water main, which is buried under about 5 feet of earth. He said that a section of the pipe will be sent to a lab for testing to help pinpoint the cause of the break. A new section of pipe will be ordered from a supplier.
In the meantime, three other water mains will be used to feed water to affected areas, officials said. An extra pumping station is also being used to help move water through the system.
Officials said they noticed a drop in the water level in the Lake Ashburton filtration plant's reservoir about the same time that residents started to call complaining about a loss of water service. Still, it wasn't until a homeowner near the park called to report the appearance of a large water-filled crater that officials knew definitely where to look for the break.
As of yesterday afternoon, there were 16 other water-main breaks throughout the Baltimore service area, said Kurt Kocher, a spokesman for the Department of Public Works. He said most of those breaks, including in the 4800 block of Hazelwood Ave., were minor.