The barge working to repair the ruptured outfall pipe has uncovered a section that bears a gouge on its exterior wall, fueling speculation that a passing ship could have triggered the spill of partially treated sewage that enters its 20th day today, officials said Thursday.
Deputy City Manager Roger Frauenfelder said Thursday that workers pulled up the damaged pipe section late Wednesday and found that it bore a deep gouge three-quarters of a mile from shore.
Frauenfelder said the gouged section was lying 35 feet south of the outfall alignment that runs due west from the E.W. Blom Wastewater Treatment Plant in Point Loma. Earlier this week, workers uncovered five sections of pipe near the 5,800-foot mark bearing large scrape marks.
City officials said earlier this week that a passing ship, or something being towed by a passing vessel, could have damaged the pipe and triggered the spill. They asked the Coast Guard for a list of ships using the area since Feb. 2, when the spill was discovered.
The spill continues to spew as much as 180 million gallons a day of treated sewage--from which 75% to 80% of the solids have been removed--3,150 feet from the cliffs of Point Loma, at a depth of 35 feet. Ordinarily, the pipe carries the sewage 2.2 miles offshore at a depth of 220 feet.
Despite the new evidence, Frauenfelder said he and other officials were reluctant to conclude that a ship could have damaged the pipe. He said he saw no connection--as yet--between the section of damaged outfall found Wednesday and scrape marks farther out.
"We don't want to draw any conclusions," Frauenfelder said. "It's still too early. But it's interesting information, and we're investigating all possibilities."
Workers lifted eight sections of pipe Wednesday and Thursday, and transported them to the 32nd Street Naval Station for storage. Frauenfelder said the 100-foot by 300-foot barge would continue to lift damaged sections of pipe through the weekend, weather permitting.
More good weather Thursday allowed county health authorities to lift the quarantine of San Diego Bay, although they noted that neither the Point Loma spill nor the overflow of raw sewage from Tijuana were believed to have contributed to toxic counts in the bay.
Instead, they blamed the quarantine in San Diego Bay and a separate one in Mission Bay, which remains in effect, on recent heavy rains that elevated readings of fecal coliform bacteria.
Only one area in the county--the tip of the Point Loma Peninsula--recorded a reading late Wednesday in excess of the legal limit. The count there was 8,200; 1,000 coliform per 100 milliliters of water is considered the safe standard for public use.
Despite the encouraging signs, county health authorities said they anticipated the 20-mile quarantine of area coastline to remain in effect through the weekend.
"We're concerned about opening up certain portions, then closing them again," Dan Avera, spokesman for the San Diego County Department of Health Services, said Thursday. "If we do open up the coastline, we want to feel confident that we can keep it open for some period of time. And we simply don't have information indicating that we can open up the coast for an extended period of time."
Avera said the area of closed coastline continues to extend from the mouth of the Tijuana River, near the international border, to the mouth of the San Diego River in Ocean Beach.
The Spill at a Glance
Amount: Daily, an estimated 180 million gallons of partially treated sewage.
Cumulative: As of Thursday, 3.6 billion gallons.
Tijuana spill: Since Feb. 6, 12 million to 13 million gallons a day of raw sewage.
Coastline closed: 20 miles, from the mouth of the Tijuana River, near the international border, to the mouth of the San Diego River in Ocean Beach.
Status of repairs: A deadline of April 4 for completion of repairs has been set. Despite several rain delays, city officials are hopeful of sticking to the deadline. This week's efforts have produced several sections of pipe about a mile from shore that bear large scrapes, fueling speculation that a passing ship may have damaged the outfall. Late Wednesday, workers lifted up a section three-quarters of a mile from shore that has a deep gouge on its exterior wall.
Pipeline repair cost estimate: $10 million.