Tunnel Vision

Metropolitan Water District workers crowd into a steel cage and descend into darkness 160 feet below ground.

They are working against the clock this week to replace a 3,000-foot-long oil extraction pipe that runs along the ceiling of the cavernous Newhall Tunnel. The tunnel, which is temporarily shut down, normally carries water from Northern California to half a million customers in northwest Los Angeles County and portions of south Ventura County.

Underground crews climb scaffolding to work on the 4-inch-round oil extraction pipe at the top of the 20-foot-high tunnel. Under the glare of floodlights, they replace damaged pipe and hangers with new plastic and stainless steel sections.

The crews work 12 hours, then return to the steel cage to ascend to the surface. They are replaced by a relief crew for another 12-hour shift.

The trouble is that naturally occurring oil in the earth surrounding the pipe has seeped into the water main, said Jay Malinowski, chief of operations. Because oil floats on water, water district workers at the Joseph Jensen filtration plant in Granada Hills have been able to easily extract clean water for homes and businesses.

About four years ago, district officials figured out how to get rid of the oil. Workers installed the oil extraction pipe that collects oil from the water supply.

Since then, however, the hangers holding the pipe to the ceiling of the tunnel have corroded, and oil has begun to reappear in the water at the Jensen plant.

“The hangers were mis-manufactured, and the whole system fell off the [ceiling] about a year ago,” Malinowski said.

The problem was discovered last summer, during the system’s peak water usage. Customers have received water from other sources while the Newhall Tunnel is closed.

“All those people who depend on the water could not be off line for seven days”--the period of time district officials estimated it would take to repair the system--he said.

While underground, Malinowski said, crews also discovered earthquake-related damage and made those repairs as well.

“There was no water interruption to customers,” Malinowski said. “I’m sure they didn’t even notice that work was being done.”