Pipe Break Did Little Real Harm, City Says

As the city’s storm-damaged sewer main returned to service late Friday, officials reported that a spill of about 63 million gallons of raw effluent into a hillside creek that closed 29 miles of beaches downstream probably did little damage to the environment.

“The rain we’ve had has really diminished any significant environmental impact,” Assistant City Manager MaryJane Lazz said. “And the heavy rain we’re expecting this weekend will help to dissipate it even more.”

The city’s preliminary report to state investigators says sewage discharged from the broken line was likely diluted 600 to 1 by rushing rainwaters in the Arroyo Conejo. And storm water is usually so contaminated anyway, that the sewer discharges “may not have a meaningful effect,” the report said.

But an ecologist at Point Mugu Navy station said that he is concerned that the 11-day flow of raw sewage upstream from Mugu Lagoon may have depleted the rare saltwater marsh of oxygen and threatened marine life such as fish, clams, mussels and shrimp.

“When you get such a large amount for so long, there is a grave concern that it may not kill all the fish or invertebrates, but have a sublethal effect that eventually results in a dwindling of the population,” said Tom Keeney, natural resources manager at the base.

“It may have redistributed the fish and the invertebrates, so they are vulnerable to predators.”

So far, however, no dead wildlife has turned up, he said.

In the city’s preliminary report, officials also concluded that the Feb. 3 pipeline break was unavoidable. Previously, some City Council members had blamed each other for delays in reinforcing or replacing the aging sewer main.

But Friday’s official report said that failure to replace the line the past two summers--as scheduled--was not due to city politics.

Improvements were “deferred due to necessary legal, planning, budgetary and financial requirements,” city Public Works Director Don Nelson said in a letter accompanying the inch-thick report.

The report was hand-delivered to the Regional Water Quality Control Board, which early this week ordered the city to fix the broken pipeline, clean up the mess downstream and make sure the pipeline never breaks again.

The report is the first of three that must be filed with the water board by next Friday. By March 15, the city must submit a plan to fix the problem for good.

The city faces fines of $5,000 a day per violation of state water law. But state officials said Friday that it will be weeks or months before the water board’s executive officer, Dennis Dickerson, decides whether the leak was unavoidable or was the result of city negligence.

“Right now we’re just trying to gather all the facts and decide what happened and could it have been prevented or was it an act of God,” said Dennis Dasker, chief of the water board’s regulatory section.

Nelson argued in his letter that the spill was “an exceptional incident” that was beyond the city’s control.

Even as city officials were presenting their official position, however, Mayor Mike Markey said that both the weather and some members of the City Council share the blame for the break.

“If it hadn’t rained it wouldn’t have broke,” Markey said. “The rains were a key factor. But had we been able to make repairs earlier we may not be in the position we are today.

“I think there’s some accountability on the council level,” he said. “It shouldn’t be blamed on staff--it should be the council.”

In building its case against future penalties, Thousand Oaks also noted that the largest previous spill from the sewer main occurred because of vandalism and not because of age or faulty construction. That spill in March 1995 discharged 12 million gallons of sewage into Arroyo Conejo.

Meanwhile, city engineers began funneling the flow of raw sewage into the patched sewer main late Friday afternoon, and officials said they expected the line to be back in full service by early this morning.

If the line holds, it would have taken nearly 11 days to fix the sewer main--which carries 60% of city sewage. Torrential rains undercut the line, snapping the 30-inch concrete line in three places on Feb. 3, then contributed to breaking the line again three days later.

With no downpours this week, workers reconnected the concrete line with a 60-foot length of steel on Thursday, cinched the steel and concrete together with huge collars and sealed the seams with tons of concrete.

On Friday, after the concrete seal had a day to harden, engineers slowly increased the pressure inside the line--first returning the flow of small sewer tributaries to the main, then as the evening progressed, routing the entire 6-million-gallon-a-day volume into the line.

At the same time, the city’s treatment plant--which had run at about one-third speed since the break--cranked up again to accept the sewage.

As part of the permanent fix of the line this summer, the city plans to spend $4.5 million to insert a strong plastic liner into 6,000 feet of the ruptured main and use it as an emergency backup to a new 42-inch line to be built next to it.

A second stretch of the same line will be replaced for $4 million the following year.

In both projects, the sewer lines will be built next to bedrock instead of on soil, helping to prevent breaks from storm runoff, officials say.