Once again, as happens every winter  — or every winter that has rain, anyway — our Humboldt County municipal wastewater systems have been pushed to the brink.

The rain gauge in Arcata registered nearly three-quarters of an inch between 11 a.m. yesterday and 11 a.m. today, with about two-thirds of that coming in the wee hours of this morning.

So: The sewage releases. Rio Dell was first to report, this morning, that at least 1,000 gallons had escaped from an overflowing manhole on Painter Street, near the banks of the Eel, impacting the waterway. It was not recovered.

Kyle Knopp, Rio Dell city manager, told the Outpost this afternoon that “sewage,” in the common understanding of the word isn’t exactly what we’re talking about, here. The problem that the city is facing is an old set of pipes running all around town that were further damaged by the December earthquake. When the rains fall, way too much water is seeping into the sewage system, overloading capacity. When it’s flushed out like this, the stuff that’s released is extremely dilute.

“We have a modern, state-of-the-art treatment plant, but the problem is getting all of this what is essentially stormwater into the plant,” Knopp said.

It’s not a cheap or easy problem to fix, Knopp said, but the city’s gearing up to apply for a bunch of grants to begin work on the problem — a problem, judging from Knopp’s normally chipper voice, that city staff is extremely sick of dealing with.

It’s much the same up in Eureka, where city recently placed the burden of replacing the thousands of ancient, porous and often leaky sewage laterals on homeowners. But the work is very far from done, and rainwater overloads the system all too often. This morning a failure at a lift station prompted 3,000 gallons of sewage to be set free into the environment. A thousand gallons of wastewater were recovered, according to the city’s report to the California Office of Emergency Services, but about 2,000 were liberated permanently. Humboldt Bay was affected by the spill.

City of Eureka Public Works director told the Outpost this afternoon that the problem, in this case, wasn’t completely down to the storm surge — in addition, there was a possibly unrelated equipment failure at this particular lift station, which is down near Halvorsen Park. They’re still investigating why that was.

As with Rio Dell, Gerving said, the massive influx of stormwater into the system during these storms meant that the sewage released was quite dilute. He said that during storm events the city’s sewage treatment plant normally receives five times the volume that it does during dry days. And the city is likewise upgrading its creaky old infrastructure, but it’s a big job and slow-going.

Gerving said that this morning the city made all the proper notifications as regards the bay’s oyster fishery, but it’s currently unknown whether the release affected oyster farming on the bay.

As a reminder: Hazmat enthusiasts can follow along in near-real time with all the stuff being released into our environment — or at least all the stuff that’s reported — at the LoCO’s Hazmat Incidents page.