[Water_news] 4. DWR'S CALIFORNIA WATER NEWS: WATER QUALITY - 4/25/07

Department of Water Resources

California Water News

A daily compilation of significant news articles and comment

 

April 25, 2007

 

4. Water Quality

 

Spill is blamed on pipe liner damage; Two cities could face stiff penalties

San Diego Union Tribune – 4/25/07

By Mike Lee, staff writer

 

CARLSBAD – A damaged pipe liner appears to be the culprit for more than 7.3 million gallons of sewage that spilled into Buena Vista Lagoon in late March and early April.

 

It's not clear what caused the breach in the plastic liner but the result was increased corrosion of a pressurized sewer main line that eventually failed, according to a preliminary report made public yesterday by Vista and Carlsbad officials.

 

The document, prepared to answer questions from water quality regulators, emphasizes the cities' fast actions after the leak was discovered. It says a Carlsbad employee was on the scene within three minutes of the initial report of a sewage problem near Jefferson Street and Marron Road.

 

The two cities jointly own the pipeline and, so far, Carlsbad and Vista have reported spending more than $1 million on the spill response. They may face fines of several hundred thousand dollars by the San Diego Regional Water Quality Control Board, which can take weeks or even months to issue penalties.

 

The rupture occurred in Carlsbad but Vista owns about 90 percent of the ruptured iron pipe and is expected to pay about 90 percent of the final tab.

 

“I certainly hope the regional board takes into consideration all of the things that we have done,” said Glenn Pruim, public works director for Carlsbad. “I don't think we could have done any better on the response.”

 

The cities' report says there's no technology that would allow utility officials to identify potential failure spots in similar situations, but that the officials are investigating the increased use of flow meters to provide an early warning if a large leak occurs.

 

“An obvious conclusion . . . would be to consider possible options for enhanced failure detection,” the report says. “While this would not serve to further reduce failure risk, it may result in more rapid leak detection and less volume discharge if another spill were to occur.”

 

John Robertus, chief of the regional water board, said his staff would assess the cities' response and determine whether a fine was warranted.

 

“When people spill sewage, we hold them accountable,” he said. “The standard is zero. . . . It's like plane crashes. You don't want any.”

 

The Buena Vista Lagoon spill is a part of a recent spike in sewage accidents across the region, Robertus said. He's confounded by the increase, which can't be explained by heavy rains or vandalism, he said.

 

Numerous sewage spills have polluted North County lagoons in recent decades, in part because wastewater lines in the wetlands commonly are pressurized and hard to access.

 

The Buena Vista rupture was among the largest in modern San Diego County history and is blamed for the deaths of about 1,700 fish – mostly bluegill and bullhead – and four birds. Response measures included pumping more than 42 million gallons out of the lagoon for treatment and monitoring aquatic life at the site.

 

The failed 24-inch line was laid in 1982 and utility officials had expected it would last several more decades. The cities' investigation says the breach was caused by corrosion outside the pipe. The inside was in “excellent condition.”

 

Because the iron pipe runs through highly corrosive soils, it was wrapped in a plastic liner to protect it from deteriorating prematurely. While the coating was installed correctly, it might have been damaged during an unrelated repair of an irrigation line about four feet away, the report says.

 

Pruim said excavation for the repair near Jefferson Street gave no indication of problems elsewhere on the main line. However, he said existing technology doesn't allow city crews to easily assess the rest of the pipe. For instance, digging it up for a visual inspection is likely to damage the plastic liner and generate more problems than it prevented.

 

The report says the cities are considering several possibilities, including using a contractor to conduct a risk assessment of the sewage system and evaluating existing and emerging technologies that could help with leak detection. It also mentions relocating the main line to Jefferson Street, but said that would do little to prevent similar spills from polluting the lagoon.  #

http://www.signonsandiego.com/uniontrib/20070425/news_1mi25buena.html

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