Investigation continues on sewage spill

A significant amount of sewage overflowed in Westlake Village Tues., Nov. 27 when a sewer line running parallel to the 101 Freeway became blocked.

The cause was building materials such as bricks and rock that must have been pulled downstream with the sewage until it built up and eventually clogged a pipeline, creating an overflow.

The blockage occurred below ground behind the new Opus West building on Agoura Road between Lindero Canyon and Reyes Adobe roads. The sewage emptied out of a manhole around 4 p.m. that Tuesday night behind the Adelphia Cablevision building also on Agoura Road near the border of Agoura Hills. It drained toward Agoura Hills.

Effluent poured out for 12 hours and traveled onto a slope next to the freeway where it was caught by a drain, according to Westlake Village city engineer John Knipe.

The Los Angeles County Sewer Maintenance District, which, according to Knipe, maintains the city’s sewer lines, came immediately and cleared the blockage within two hours, he said.

The building materials found were most likely from the Opus West construction project, Knipe said, but definite answers aren’t yet available. An investigation has been underway since the incident.

According to Ken Pellman of the County Department of Public Works, vandalism might be an explanation for the blockage in which, large chunks of debris might have been thrown down storm drains.

"Somewhere up the line, someone put it into the (sewer) system," Pellman said.

Maintenance crews vacuumed the spillage into the morning hours, Knipe said. A large amount of waste overflowed. He declined to be more specific.

"This is a new occurrence for us," Knipe said. Whether the water regulation board levies fines, he doesn’t know. "That’s being looked at by the city attorney’s office," he said. "And then, of course, our report goes to the Regional Water Quality Control Board in Los Angeles." Many steps must be taken before the city knows the outcome, he said.

Additional costs in terms of damage are nonexistent at this point, Knipe said. The main costs would be for the maintenance workers who cleaned up the mess, he said.

––Michael Picarella