An atmospheric river dumped more than
4 inches of rain in some areas of San Luis Obispo County on Feb. 13 causing a sewage spill in Avila Beach and prompting the rescue of nine from the flooded Salinas Riverbed in Paso Robles.
The National Weather Service issued a flood warning effective Thursday, Feb. 13, and warned of potential 60-mile-per hour wind gusts. According to SLO County Public Works, that day SLO saw more than 3 inches of rain in 24 hours, and areas like Atascadero, Paso Robles, and Arroyo Grande received around 2.5 inches. The Hearst Castle area saw nearly 6 inches.
Paso Robles Fire and Emergency Services Battalion Chief Jay Enns told New Times that at around noon on Feb. 13, the riverbed was dry. By 3 p.m. it was raging, and by 4:45 p.m. they had received a call that five individuals needed rescuing.
But upon arrival, Emergency Services used drones and a helicopter that located four more stranded.
“So, once we got all those people back across, we sent our boat further upriver, and they located four more individuals, and so we brought them across safely and had it all wrapped up within about an hour of the initial call.”
No one was injured, Enns said.
“I would just reiterate that it’s really important for the public in any situation, not just this one, but in any situation where there’s evacuation warning issued that they should pay attention to that and get their stuff and leave,” he said.
On another side of the county, Water Resource Recovery Facility Supervisor Patrick McGrath said that on a typical day, the SLO County Wastewater Facility gets about 3 million gallons of municipal wastewater from SLO, Cal Poly, and the airport.
But on Feb. 13, the facility had 20 million gallons of waterflow, causing sewage to spill into the San Luis Obispo Creek and into Avila Beach waters.
Initially, it was estimated 50,000 gallons of materials had spilled, but by the next day, the treatment plant reported it was 7,800 gallons.
With the facility in its fifth and final year of a major upgrade, McGrath said unfortunately it was the perfect condition for an overflow.
“The plant is designed and engineered to handle flows in excess. I mean, it’s atypical. But these are flows that we are familiar with. We just had kind of a unique circumstance,” he said. “We’re still in active construction. So active construction coupled with … these significantly inflated flows, coupled with what we’re now looking at as a partial power failure just created the conditions for an accidental release.”
County Environmental Health closed the beaches impacted by the spill. While McGrath said beach closures are typically three days, he cautioned beachgoers to avoid getting in any water for a few days after a major storm, regardless of if there was a sewage spill or not.
“It’s because anything that’s in the creek, the mud, animal feces, anything that’s in there, it’s wildlife habitat that all gets flushed out to the ocean,” he said. “And believe it or not, these flows of that creek can exceed a flow rate of 300 million gallons per day.”
The city takes full responsibility for the spill, he said, something that hasn’t happened at this site in a decade.
Once the treatment plant finishes construction, it will have features like flood walls and other programming to handle higher capacities of water in case of major storms.
“This is not a common occurrence for the city of San Luis Obispo water resource recovery facility, and we don’t expect this to happen again,” he said. Δ
This article appears in Feb 20 – Mar 2, 2025.