AFTER THE DELUGE: CLEANUP CONTINUES : Sewage Spill Should Be Fixed by Now : Water district officials expected to fix pipe that let 6 million gallons of untreated waste pour into sea at Dana Point.

Water district officials expected to stop a massive spill by late Wednesday night, halting the flow of millions of gallons of raw sewage into the ocean that began Monday.

About 6 million gallons of untreated sewage spilled into Oso Creek after a major sewer line broke Monday afternoon near Jeronimo Road in Mission Viejo. A rain-soaked slope above the underground pipe caved in, causing a 40-foot rupture in the line.

Late Wednesday, crews hired by the Santa Margarita Water District were expected to complete installation of a temporary pipe and pump that is diverting waste around the break and back into the system, said Bob Regan, director of operations at the water district. Regan said permanent repairs to the damaged line can now begin.

“Everything is going according to schedule,” said Regan, adding that it will take 30 to 60 days to make permanent repairs.

The break had forced the waste into adjacent Oso Creek, which flows via Trabuco and San Juan creeks to the ocean at Doheny State Beach in Dana Point.

County health officials say five miles of beach from the point at Dana Point to Avenida Pico in San Clemente will remain closed for at least a week, maybe longer, due to high bacteria counts.

The sewage spill is the largest in Orange County since 1981, when 6 million gallons of raw waste fouled Newport Harbor.

It took the workers almost three days to stop this week’s flow because rain-soaked soils around the area were too unstable to bring in heavy repair equipment. They first had to resurface an eroded service road with gravel, then install a temporary pipe and activate a huge, portable pump.

The 18-inch-diameter pipeline handles waste from about 12,000 homes in Mission Viejo, Rancho Santa Margarita and Coto de Caza. Water and sewer service was not interrupted.

The county’s largest spill occurred in January, 1969, again when storms flooded the area, and 10 million gallons of raw sewage from Riverside County spewed into the Santa Ana River every day for several weeks. The waste flowed into the ocean off Huntington Beach, closing beaches from Newport Pier to Huntington State Beach for months.

Another huge spill occurred in 1980, when 9 million gallons a day flowed into the ocean off Doheny for several weeks because of malfunctions at the Dana Point waste-water plant.