A contractor works to clean up a sewage spill in Rio Dell. | Photo via Kyle Knopp.

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PREVIOUSLY: Sewage Incident in Rio Dell

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The City of Rio Dell is experiencing an ongoing hazardous materials spill as heavy rainfall infiltrates outdated sewer pipes that were damaged during the 6.4 magnitude earthquake that struck on December 20.

An estimated 140,000 gallons rain-diluted wastewater has spilled out of a manhole cover at the end of Painter Street, near the city’s wastewater treatment plant, and the spill is continuing at a rate of about 50 gallons per minute, according to Rio Dell City Manager Kyle Knopp.

“We’re doing our best to recover as much of that as we can,” Knopp said. Tanker trucks are being filled onsite and then driving the collected materials to the nearby wastewater plant. Knopp said there is no immediate public health risk.

Rio Dell officials notified the California Office of Emergency Services of the spill on Wednesday, noting that the release is ongoing and may impact the Eel River.

“Rio Dell has a pretty state-of-the-art treatment plant,” Knopp told the Outpost this morning. “The problem is the collection system. The pipes that go to the plant — as you get toward the plant — are too small.”

They’re also constructed from concrete that likely cracked during the recent quakes, including a 5.4 temblor that hit the region on New Year’s Day. The cracks allow inflow and infiltration, often abbreviated as I & I. 

“When you have a concurrent rain event without the breaks [in the pipes] being addressed, you will get more and more [inflow and infiltration] in the system and it continues to get worse,” Knopp said.

He reiterated that the spill is comprised of mostly stormwater, not raw sewage.

“When you go down to the site it doesn’t smell,” he said. “It’s just a manhole pushing out mostly stormwater.”

Knopp speculated that much of the damage may be located in pipes that run under Hwy. 101 where it carves through the middle of Rio Dell. Four concrete wastewater pipes that date back to the construction of the current highway run underground in that location,  “right in the damage zone,” Knopp said. 

The municipal water system has six cross-highway connections in the same area, and Knopp said two of the six are down as a result of the quake. That’s why he suspects the wastewater leaks are in the same area.

City staff have been working to assess the situation with help from employees of the City of Eureka. Knopp said he expects more assistance to arrive today, though he’s making sure safety is the No. 1 priority.

“When we have hurricane-force winds and branches falling I’m not going to have my crew out there,” he said.

Crews resumed work this morning, but Knopp couldn’t say when the spill might be fully contained. While leaks in the municipal water system are fairly evident and easy to locate, cracked and leaky sewage pipes are not readily apparent. 

Those pipes are largely constructed from “older technology” — clay and concrete materials that are prone to leaks. 

“The old thinking was ‘dilution is the solution to pollution,’” Knopp said. “Having I & I was not necessarily a problem when the systems were installed. Now, under current regulations, it’s a big problem. But we have to be smart and know where to put money toward fixes.”

The city has a project proposal before the state water board to upsize the water pipe leading into its wastewater treatment plant.

“That would eliminate these SSO’s [sanitary sewage overflows] we’re having,” Knopp said. “It would be a quick fix, but we need the state to step in. It’s still an expensive project — doable but expensive.”

The leak area is near the end of a road and has been segregated off, according to Knopp. Neighbors have been notified. 

“Just know that we have been working on a strategy to comply with the state law entities [governing such spills] as efficiently as possible for ratepayers,” Knopp said. “We want to get this situation fixed and we’re hoping the state can expedite solutions to some problems already on the table to solve this.”

As if the earthquake and flooding weren’t enough, the city continues to experience problems with its internet and phone services. The network outage “could be storm related,” Knopp said.

With a bit of gallows humor, the city manager noted that things could always be worse. 

“The locusts are not here yet,” Knopp said.