A break in a sewer line beneath a Sonoma field received temporary repairs Monday after weekend rains overwhelmed the aging 42” pipe.
Work crews installed sand bags and a metal patch on the pipe that caused a sinkhole near Splude Road and Broadway. An estimated 2,250 gallons of untreated and partially treated wastewater was released in the March 20 incident, an official said, but there was never any health threat.
The overwhelming amount of rainwater diluted any waste, according to Brad Sherwood of the Sonoma County Water Agency.
“There are no worries about contamination,” he said.
Another wastewater overflow was reported on Oman Springs Court in Boyes Hot Springs. Agency work crews monitoring potential trouble spots discovered that rainwater had infiltrated the sewer line.
A vacuum truck was used to clear the estimated 4,575 gallons of wastewater.
Sherwood said that here too health concerns are negligible. “It is unlikely that fish or wildlife were affected by the overflows due to high amount of water entering the watershed.”
The flow in Sonoma Creek in Agua Caliente is usually less than 1 cubic-feet-per-second, he said. When the overflow occurred, the flow were over 1,500 cfs.
The weekend storm dumped over two inches of rain on Sonoma Valley. “”When the rain stopped, the problems stopped,” Sherwood noted.
An overflowing Schellville Creek contributed to the Splude Road sinkhole. Crews were alerted to the breach when tree branches and a large amount of rock and dirt began entering the treatment plant.
Workers walked and drove the pipe route until they discovered the damaged area.
A permanent repair to the pipe will be made later this summer. The same section of failed pipe had already been targeted for replacement under the district’s capital improvement plan.
The Sonoma Valley County Sanitation District operates and maintains 118 miles of wastewater collection pipes, many over 50 years old.
“Old, cracked wastewater pipes allow the infiltration of rainwater which can overwhelm wastewater collection pipes and treatment facilities,” said Sherwood.