An estimated 100,000 gallons of raw sewage spilled into the streets of a Santa Clarita neighborhood and flowed into a nearby dry riverbed when construction materials clogged a major sewer line Sunday night, authorities said.
The sewage backup occurred in the area of Santa Clara Street and Honby Avenue in Canyon Country about 8 p.m. when a 21-inch-wide underground pipe became clogged by chunks of concrete and rock. The untreated sewage flowed up into the intersection of the streets and drained into a ditch that then carried it to the Santa Clara River bed.
It took crews more than four hours to get the line flowing again, and the cleanup took until Monday afternoon. After the cleanup, authorities said there appeared to be no environmental or health hazard.
"The system was backed up so much it was coming out of the manholes," said Richard Wunderlich, who heads Los Angeles County's Sanitation District plant in Valencia.
Wunderlich said the concrete and rock had apparently been illegally dumped into a sewer drain by vandals or negligent contractors and that it stopped almost all of the flow through the area's main sewage line.
A sewer crew used a truck equipped with a high-pressure hose to send a powerful burst of water into the clog to break it apart, Wunderlich said.
As normal flow was regained in the sewage line, the county used vacuum trucks to clean the spilled sewage from the streets, drainage ditch and riverbed. The area was washed down and a chemical disinfectant was used to kill bacteria, Wunderlich said. Dirt in the spill area of the riverbed will be dug up and turned over, he added.
Wunderlich noted that no private property was damaged by the spill and said the cleanup precautions would head off any environmental or health dangers.
"It's not a good thing to have happen but we cleaned it all up," he said. "I don't expect any problems."
After the cleanup, the county's Department of Health Services inspected the area to determine if the spill posed any threat to the area's water supply, but no danger was found.
"There is a lot of ground water in that area. The concern would be to make sure that none of the water wells along the Santa Clara River would be affected by this," said Jack Petralia, director of the department's bureau of environmental protection.
Petralia said there were no wells in the immediate vicinity of the spill. He said the chances of any other wells along the river being contaminated were slim because sewage that seeps into the ground is usually filtered of all impurities within 50 feet while wells normally draw water from more than twice that depth.
Times staff writer Philipp Gollner contributed to this story.