Judge Delays Deadline on Outfall Pipe : Infrastructure: U.S. court agrees that repairs on ruptured sewage outfall line take precedence over construction of an extension.

A federal judge Friday postponed a deadline for the city of San Diego to begin lengthening its now-ruptured sewage outfall, saying that construction could not possibly begin May 1 because of a massive spill of partly treated waste off the coast.

As part of a longstanding lawsuit, District Judge Rudi M. Brewster had ordered the city to begin construction of its long-planned 2-mile outfall extension by May, which would require that bidding begin Thursday. The extension was scheduled to be completed in 1994.

Brewster agreed that the unforeseen rupture of the outfall pipe, which has been spewing 180 million gallons a day of partly treated sewage into the ocean 3,150 feet offshore, takes precedence over new construction. The still-unexplained failure of the 2.2-mile pipe was detected Feb. 2.

The judge also denied a request by the Sierra Club, a party in the federal suit, that would have halted, for one year, construction on a second outfall planned for the South Bay.

Ted Bromfield, chief deputy city attorney for San Diego, called Brewster’s ruling “a very substantial victory for the ratepayer and the city. If we were forced to put new pipe on old pipe--that turns out to have to be replaced--the ratepayer would end up paying more.”

Bromfield said the city hopes to hire by early next week an independent forensic consultant to determine the cause of the outfall rupture and have the report completed within a month. Work continues on repairing the break, which occurred at a depth of 35 feet.

Asked about the cause of the rupture, James J. Dragna, an attorney representing the city, told the judge the independent expert “may conclude it was an anchor. Or, he may conclude it was a water hammer.”

Officials say that, because sections of pipe a mile offshore bear deep gouges, they speculate that an anchor or something being towed by a passing ship may have damaged the outfall, which will have 25 new sections when repairs are completed in April.

Workers at the Point Loma treatment plant told The Times recently that a large air bubble, known as a “water hammer” may have been triggered the rupture. They said that exercising a throttling valve at the same time a diversion gate was being opened may have created the phenomenon as early as Jan. 31. The Coast Guard first detected the spill two days later.

On Friday, Brewster ordered all parties in the case--the U.S. Environmental Protection Agency, the state Regional Water Quality Control Board, the city and the Sierra Club--to reconvene in Federal Court March 20 for a progress report from the city.

Attorneys for the U.S. Justice Department, which represents the EPA, opposed the city’s request, saying Friday that a delay wasn’t warranted until the city could state specifically why previous deadlines couldn’t be met.

Despite granting the city its delay, Brewster asked numerous questions about the ruptured pipe. The city replied by saying that, after fixing the break, it hopes to construct a tunnel underneath the ocean floor to handle waste disposal.

City officials said the tunnel will burrow 500 feet deep into solid rock near Sunset Cliffs, running beneath the ocean floor, then gently sloping upward before depositing the effluent 4 miles offshore.

The existing outfall system deposits the sewage 2.2 miles offshore, at a depth of 220 feet.

Friday’s action was the latest round in a suit filed by the EPA in July, 1988. The EPA is charged with enforcing the Clean Water Act, which mandates that every city in the country employ, at a minimum, secondary treatment of sewage.

San Diego’s method is advanced primary, which removes less of the suspended solids in the effluent. “As the sixth-largest city in the country, that makes us a big fat target,” attorney Bromfield said.

Since Brewster’s order to begin construction of an outfall extension, Bromfield said the city has considered two new options of sewage disposal: the tunnel and a pipe that runs parallel to the existing structure.

The judge conceded that the current rupture changes the complexion of preconceived plans.

“If we’re going to extend the existing pipe another 2 miles, you at least have to make sure it’s stable,” Brewster said. “To add another 2 miles on a pipe that fails again in 10 years. . . . Well, at that point, none of us could say we weren’t able to foresee that possibility.”

Brewster said he was intrigued about the tunnel concept but asked about the threat of earthquakes, noting, “Wouldn’t you have sewage seeping up through the ocean floor?”

“We’ve been told that 500 feet down, it’s very stable,” Bromfield said.

Bromfield told the judge that the break now has “everything on hold,” and that the city is facing five legal actions due to the spill.

Earlier this week, county health authorities reduced the 20 miles of closed coastline extending from the international border to the mouth of the San Diego River. About nine miles remain under quarantine, with beaches from Coronado to Imperial Beach now open.

Bacterial counts released Friday revealed high readings at the tip of Point Loma (9.4 times the legal limit); the Point Loma treatment plant (55 times the safe standard), and the Point Loma Navy property (19 times the limit).

Officials said Friday that an incoming storm, expected to bring rain by Monday, could delay repairs and send bacteria counts soaring again.