Water quality officials said Friday that preliminary tests showed no significant environmental damage or threats to public health as a result of the worst raw sewage spill into the Russian River in more than a decade.
But the estimated 100,000-gallon spill near Guerneville spotlights concerns that the aging pipes that transport sewage beneath and near the river for miles may be at risk for more ruptures.
"I think we have a system that is aging at this point, just like almost all of the systems we are operating, and these kinds of things happen," said Pam Jeane, assistant general manager of the Sonoma County Water Agency.
Thursday's spill raised immediate concerns for the environment, and prompted officials with the Sweetwater Springs water system to shut off wells and use stored water for about 1,000 customers in the Monte Rio area.
The pumps were turned back on at about 9 a.m. Friday after tests revealed no signs of contamination, General Manager Steve Mack said.
"It's over. We're back to normal," he said.
County public health officials posted signs at beaches downstream from the spill warning people not to swim in the water.
The county took water samples to test for E. coli, a bacteria that can cause diarrhea, urinary tract infections and other illnesses. The results were expected Saturday, said Christine Sosko, Environmental Health Section Manager for the county's Department of Health Services.
Sosko said based on the river's strong flow, officials were "not anticipating" the sewage spill to cause any health problems.
State water quality officials are conducting their own investigation, which could lead to fines or other penalties levied against the county Water Agency, which operates the sewer system.
"Certainly there was a discharge into the river. There's no question it's a violation," said Matt St. John, executive officer of the North Coast Regional Water Quality Control Board.
He declined to speculate on what the penalty might be. Similar cases in the past have resulted in fines for the Water Agency.
The agency operates the sewer lines for the Russian River County Sanitation District. Thursday's rupture occurred in the main sewer line serving more than 3,000 customers in the Guerneville area.
The 16-inch steel pipe encased in concrete ruptured around 12:20 p.m. Thursday at Beach and Orchard avenues, a rural neighborhood on the east side of the river just outside Guerneville.
A resident who was in a small community park spotted moisture on the ground late Wednesday night and reported a leak. Water Agency repair crews were working to repair the leak mid-day Thursday when it ruptured, sending untreated sewage bubbling to the surface. The brown water gushed over the edge of the park, down a hill and into the river about 40 yards away.
While workers carefully removed about 12 feet of pipe and fit in a new section of PVC, eight tanker trucks were used to collect the diverted sewage.
The repair crew had to chip away the old concrete mortar lining the pipe and brush off all the bits of grit to allow for a good connection with the new pipe, Water Agency officials said.
About 40,000 gallons per hour of sewage flow through the pipe to a nearby treatment plant. The leak lasted from about 12:30 p.m. to 3:30 p.m.
The fix was done by about 12:45 a.m. after the new section of pipe was tested and worked, said Brad Sherwood, spokesman for the Water Agency.
"We all waited, holding our breath as we let the waste water go through and it held," Sherwood said Friday.
Officials said the Water Agency was not testing the viability of underground sewer lines in the Russian River district prior to the spill, in part because it would require shutting lines down and arranging for alternative methods of transporting waste.
The testing process involves taking the pipe out of service in order to launch a robotic camera and other equipment inside it to probe for any problems, said Mike Thompson, another assistant general manager for the Water Agency.
He said the agency had contracted for a vulnerability study of the lines prior to Thursday's spill, and that because of the incident, officials are planning to conduct more extensive tests of the sewer lines in the fall.
"The break beat us to it, so to speak," he said.
It was unclear Friday how much monitoring of the lines is required as a condition for the Water Agency to operate the sewer and water lines.
St. John said the Water Quality Control Board is reviewing the agency's permit "to determine potential appropriate corrective actions."
The Water Agency sent crews out Friday to replace the sod and bark at the park where the rupture of the pipe occurred. The agency also will repair the park's irrigation system, which was damaged during the pipeline work, Thompson said.
He said the agency was not planning to conduct soil tests at the park because the rupture occurred far enough underground to prevent people from coming into contact with any potential contamination.
Thursday's spill appears to be the largest since 1999, when 100,000 gallons of raw sewage flowed into the river over five days as the result of employee error at a small pumping station.
That same year, more than a million gallons of partially treated wastewater flowed into the river during three days of flooding, when high water inundated the treatment plant near Guerneville. And in 2010, about 300,000 gallons of treated wastewater spilled into the river.
Brenda Adelman, chairwoman of the Russian River Watershed Protection Committee, on Friday said Thursday's spill was the inevitable result of an aging system.
"I'm not blaming anybody," she said. "These things will happen when people put in these systems in West County communities. It's not always the best way to go."
Adelman complained about having to pay $1,253 annually for a sewer line hook-up when, in her opinion, the money charged to ratepayers has not been enough for the Water Agency to cover needed maintenance and repair costs.
She predicted more spills in the future.
"I'd call it death by a thousand cuts. This is part of a big picture and problem that goes on all the time," she said.
(Staff Writer Randi Rossmann contributed to this report. You can reach Staff Writer Derek Moore at 521-5336 or derek.moore@pressdemocrat.com. On Twitter @deadlinederek.)
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