Algae Blooming in South Fork Eel

POTENTIALLY TOXIC ANABAENA grows in a bed of decaying Cladophora in a South Fork Eel tidewater near Phillipsville, pictured on Aug. 1. (Courtesy Patrick Higgins)

POTENTIALLY TOXIC ANABAENA grows in a bed of decaying Cladophora in a South Fork Eel tidewater near Phillipsville, pictured on Aug. 1. (Courtesy Patrick Higgins)

It’s hot, so in an ideal world taking a swim in the South Fork of the Eel would be the thing to do.

But this is not an ideal world.

Proof of that are the “mats of floating algae,” as a recent press release by the Eel River Recovery Project put it, that can be seen in the river as it flows through Tooby Memorial Park near Garberville.

The river there is “chock full of algae, in the eddies, in the deepest parts of the pools and everywhere else,” said Recovery Project Managing Director Pat Higgins, speaking last Friday.

Same story in Miranda, where “gobs of algae” can be seen in the water. By the time the river is at Phillipsville, “it’s looking dangerous,” Higgins said — meaning that lurking in the water could be cyanotoxins that can shut down the respiratory system if ingested.

Cyanotoxins have been known to cause death in dogs that have gone into the river and then licked their fur after getting out.

Not everywhere on the South Fork is bad for swimming, indicated Higgins, a fisheries biologist who conducted a one-man “reconnaissance” of the river earlier this month.

“If you go way up, like at Standish-Hickey [State Recreation Area], it’s still delightful [for swimming]. But the river starts to break down around Benbow, below the East Branch at Tooby. [So] if you’re talking about down low, go to the beach [instead],” Higgins advised.

The press release said swimming conditions were “excellent” around Leggett and “still good as far downstream as Benbow.” The presence of algae at Tooby “and in pools downstream on the South Fork and lower Eel River below Dyerville make swimming less attractive and may present an increasing risk of swimmer’s itch,” the release added.

Last month, the Humboldt County Department of Health and Human Services, along with the Mendocino County Department of Environmental Health and the North Coast Regional Water Quality Control Board jointly issued a statement warning people who want to recreate in fresh water bodies to avoid contact with algae.

“Not all algae is noxious, and much of the algae in the Eel is green algae that poses no health risk,” the recovery project press release noted. “But the public needs to be aware of and avoid specific habitat areas that can foster toxic algae and [that] pose the greatest risk to human and animal health.”

One place to avoid, the release went on, are “stagnant areas on the margin of the Eel and its tributaries.” Such warm-water, nutrient-rich areas “create an ideal medium” for the growth of cyanobacteria, particularly in late summer — in other words, now.

“The major source of toxins in the Eel River is Anabaena that forms dark green spires underwater that often have oxygen bubbles coming off them during the peak of photosynthesis,” the release said. “Pieces of cyanobacteria float up with the bubbles and may form a scum that can also be toxic in slack water downstream.”

Higgins put it in simpler terms during the interview. “I don’t go in the water where it’s foamy,” he said.

What this all boils down to is that the river is sick. The basic reason as cited in Higgins’ press release is a loss of tributary flow.

“Loss of tributary flow contributes to stagnation, warming and toxic cyanobacteria blooms in main river reaches downstream,” the release said. “Flows at many Eel River U.S. Geologic Survey flow gauges are far below averages for the period of record, despite the nearly average rainfall this past winter.”

The release noted that a recent flow assessment showed that flows on the South Fork at Leggett are not much different than flows downstream in Miranda, where “flows would historically have doubled in this reach.”

“The South Fork used to be a gaining stream. It picked up flow below Leggett. Now the flow is the same in Miranda as it is in Leggett,” Higgins explained in the interview.

There are a number of reasons for the diminished flows, not least increased water diversions to feed the region’s abundant marijuana grows. But Higgins’ release also points to another culprit — dense stands of young, thirsty trees that have sprung up following the widespread logging that took place in the Eel River watershed.

“Water withdrawals play a role in flow depletion,” Higgins’ release allowed. “But recent studies suggest increased evapotranspiration by early seral forests may be an equal or greater factor in reducing summer base flows.”

Higgins, in the interview, said that “people are diverting water more than they used to” to water pot gardens. He also said that residential development is leaving a larger footprint. But he indicated that people shouldn’t overlook the impact of the thicket of trees carpeting the landscape, a thicket that came in following the removal of the old growth.

“Everywhere you look there are even-aged stands of fir and hardwoods, [each tree] six feet apart as far as the eye can see,” he remarked.

One result of these impacts — another is sediment run-off from roads which also reduce flows — is that feeder streams are becoming disconnected from the main-stem. “A number of tributaries are underground,” Higgins said. “The South Fork should be taking water [from] the East Branch [of the South Fork of the Eel.] Instead, “that’s underground.”

“Fish Creek above Benbow is underground. Sprowel Creek is still connected and flowing and Redwood Creek may or may not be. Salmon Creek is underground.”

“Many of the feeders that would add cool water [to the South Fork] do not do so,” Higgins summed up.

One might assume that Higgins’ point in publicizing the results of his observations is to make sure that people thinking about taking a swim in the Eel understand what they might be getting into.

But he said that as far as he could tell during his reconnaissance, that message is already well understood. By the time the river is at Garberville, “people are not swimming.”

“The public doesn’t need advisement. People are staying away in droves,” Higgins declared.

His intent instead is to mobilize folks into taking steps to improve things on the Eel.

“The recovery project wants to share information about the impairment of water quality and flow so we can work together as a community to reverse these conditions,” he explained. “That’s the sound bite.”

As for what the recovery project is already doing, the release had this to say: “ERRP is partnering with the University of California, Berkeley, the North Coast Regional Water Quality Control Board and Round Valley Indian tribes to monitor cyanotoxins at 15 Eel River basin locations. Dozens of volunteers are also helping deploy water temperature sensors at more locations.”

More information about the recovery project can be found at People can also call 707-223-7200.