Green algae set off red flags at the headwaters of the South Yuba River where Donner Summit wastewater was being discharged earlier this summer.

The Donner Summit Public Utility District received a notice of violation from the California Regional Water Quality Control Board, Central Region on Aug. 8 for fungi, slimes and other objectionable objects resulting from discharge into the river in June.

“We’re taking this very seriously,” said Tom Skjelstad, general manager for the utility district. “We have identified the algae and it is not a public health concern.”

The district, which normally switches to surface spraying of treated wastewater in the summer months and discharges into the Yuba only in the winter, was asked by the water quality control board to continue discharge until they could take water quality samples, Skjelstad said.

Skjelstad said this was the first time in 20 years of operation that such a discharge occurred.

“Even the downstream users that reported this said this is the most unusual thing they’ve every seen,” he said. “With algae showing up in Tahoe and one person reporting it in Lola Montez, we’re wondering if this is a regional thing.”

Ken Landau, assistant executive officer for the California Regional Water Quality Control Board said the algae couldn’t be completely pinned on the utility district’s discharge with 100 percent certainty.

“It has certainly been a real dry year with very little diluting water, and it was warmer earlier in the year,” Landau said.

But Skjelstad said it is reasonable to conclude that the district is at least a major contributor, saying that getting rid of nitrates has been a constant problem for the district.

Just as nitrates feed algae and can cause a bloom, the wastewater plant uses biological treatment to “eat” the nitrates as a way to get rid of them before they reach the river, Skjelstad said, but the organisms have a tough time on the Summit.

With the large second-home owner population on the Summit, wastewater volume changes drastically throughout the year — meaning the organisms have nothing to eat sometimes and die off, then are overwhelmed later.

Cold water also makes it hard for the organisms to operate, Skjelstad said.

The district plans to enact a more extensive monitoring plan along the South Fork of the Yuba, Skjelstad said, responding to the water quality control board by the Sept. 8 deadline.

Environmental concerns Jason Rainey, executive director of the Nevada City-based South Yuba River Citizens League, said he is concerned with the frequent violations. “Algae is problematic because of its recreational impact, but more importantly it’s robbing dissolved oxygen from other life forms in the river,” Rainey said. “The river is close to capacity on what it can take even with the plant’s expensive upgrades.” And that, he said, could have a significant impact on the growth of Donner Summit. “I think it will continue to be a limiting factor for development,” Rainey said. “[With Royal Gorge] they are calling for a near-doubling of plant capacity, and their track record indicates doubling, even with upgrades, does not bode well for the future of the Yuba River.”