Santa Rosa proclaims flood emergency after 250 million gallons of treated sewage released into streams
Santa Rosa officials said Tuesday that managers at the city’s wastewater plant have been forced to release at least 250 million gallons of treated sewage into two creeks and the nearby Laguna de Santa Rosa amid record inflow to the facility that began in last week’s storm.
The three-day deluge pushed more than five times the normal flow of wastewater and runoff into the city’s Laguna de Santa Rosa plant, City Manager Sean McGlynn told the City Council on Tuesday. It was the highest inflow ever recorded at the site, according to the city.
To avoid overwhelming the Llano Road facility, managers began last Wednesday releasing fully treated sewage into Santa Rosa and Colgan creeks and the rain-swollen Laguna, which overtook city blocks on the eastern edge of Sebastopol, including the upscale Barlow shopping and business district.
The emergency release is ongoing, city officials said Tuesday. All three waterways drain into the Russian River.
McGlynn’s report came as the City Council affirmed a local emergency declaration he made last week at the end of the storm. The move is meant to ensure the city has both the flexibility and legal protection to alter operations at its wastewater plant, where flows have abated but remain higher than normal.
Partially treated waste also was diverted last week into storage basins, with plans now underway to fully treat that sewage. That diversion took place from late Tuesday to Thursday afternoon and has not impacted nearby waterways, according to the city.
The plant has enough remaining storage space to handle the extra volume from this week’s rain, Santa Rosa Water officials said. They have yet to discover any damage at the plant stemming from the past storm, which dumped a one-day record of 5.66 inches of rain on Santa Rosa.
But the local emergency, set to remain in place through March, will allow city workers to monitor the plant and respond should damage pop up, officials said. It could also give the city some additional wiggle room with state water quality regulators who enforce strict standards governing the plant’s operation and releases.
The Llano Road facility treats wastewater from about ?230,000 customers in Santa Rosa, Sebastopol, Cotati and Rohnert Park.
McGlynn, explaining his reasoning for emergency declaration, alluded to the benzene contamination caused in Fountaingrove water pipes by the Tubbs fire in October 2017, but not discovered until the following month.
“We’ve had experience before that damage does not always manifest itself immediately,” McGlynn said. “It can take a period of time to fully understand the implications. … This affords us an opportunity to really assess what impacts are to our facility and protect the city.”
The City Council ratified the 30-day emergency on a 6-0 vote at Tuesday’s special public meeting.
McGlynn’s initial proclamation Thursday came on the same day Gov. Gavin Newsom declared a state of emergency in Sonoma and four other Northern California counties related to storm damage.
In Sonoma County, flooding caused an estimated $155 million in damage to 2,600 homes and more than 570 businesses, while also impacting roads and other public infrastructure, county officials said.
At the Laguna wastewater plant, “extremely high flows” were reported - up to 105 million gallons - more than five times the typical daily inflow of 19 million gallons, said Jennifer Burke, the interim city water director. With the latest round of wet weather, flows were at about 46 million gallons Tuesday.
“There’s still a lot of water in the system,” Burke said.
Under routine operations, treated wastewater from the plant is sent north to The Geysers on the Sonoma-Lake county border to recharge the geothermal field. It is also used for farm and urban irrigation.
Sewage treatment involves a multiphase process that ends with exposure to ultraviolet light.
While the wastewater released into the creeks and the laguna was fully treated, officials said, some sewage that was not fully exposed to UV rays was diverted into storage basins and needs to be retreated, Burke said.
Under a state permit, the city plant is allowed to discharge treated sewage into nearby waterways, but the discharges that began last week occurred without data collection typically required by state water regulators.
The city has been in talks with state regulators about possible ramifications due to the rainstorm since last week, Burke said. The city this week will have to file a report about the discharges with the North Coast Regional Water Quality Control Board.
A representative of the Santa Rosa-based agency could not be reached for comment Tuesday.
Burke became the city’s interim water director effective Monday, taking over for Emma Walton, a deputy director who had held the temporary position since Dec. 10 after former director Ben Horenstein resigned to take a job in Marin County.
The transition’s timing had been planned since Horenstein’s departure, and Burke is scheduled to serve as the interim through May 12, a city spokeswoman said.
You can reach Staff Writer Will Schmitt at 707-521-5207 or firstname.lastname@example.org. On Twitter @wsreports.