Sutter fishing guide James Stone watched with rising frustration this rainy season as the operators of the troubled Oroville Dam repeatedly raised and lowered the flows on the Feather River.
River levels seesawed over the course of four shutoffs of the dam’s battered spillway. Mile after mile of riverbanks crumbled near Live Oak and Yuba City. After one particularly abrupt change in flows, thousands of fish were unable to follow the rapidly receding water back into the main channel and became stranded in shallow pools along the flood plain.
Dozens of trees – some of them from orchards growing on bluffs along the channel – toppled and are now submerged or are in danger of falling in. All that sandy soil and silt from the crumbling banks – combined with spillway debris washing down – have created massive new sandbars and covered large portions of the river bottom. Stone says prime gravel that Chinook salmon used as spawning beds is now covered up with silt.
“In my opinion, we did 50 years of damage in one year,” said Stone, the president of the NOR-CAL Guides and Sportsmen’s Association, while piloting his boat up the river near Yuba City on Wednesday.
Two state lawmakers from the area have sided with Stone and think the state should clean up the river. But state dam operators counter that it’s not clear whether the fluctuation in water releases from Oroville harmed the river. They argue that some bank erosion, sediment build-up and fish stranding would have occurred regardless this year, given Northern California’s record rainy season.
At issue is how people have been using the highly modified Feather River in the six decades since the state built Oroville Dam and began controlling the river’s flow.
Long sections of the Feather River’s nearly 70-mile channel below the dam sit below tall, steep banks cut into sandy soil. It’s only during the wettest of years that high flows released from Oroville Dam crest those banks and water inundates flat flood plains on either side of the channel. The flat areas are flanked by major flood-protection levees. Farmers who have orchards between the river channel and the levees know their orchards will be flooded from time to time.
In a normal year, dam operators manage Oroville releases by gradually dialing them back to help prevent levees and river banks from caving in. This gradual easing also gives any fish that were swimming in the flooded areas more time to follow the river back into channel.
This year was anything but normal. After the dam’s spillway cracked in February, the state Department of Water Resources struggled to figure out how to best unload the water pouring into the dam from rain and snow without doing more damage to the spillway.
Oroville’s operators say they had no choice but to rapidly shut down spillway flows so they could perform inspections and do other work on the spillway while managing climbing lake levels. After the crater formed in the spillway on Feb. 7, Department of Water Resources engineers were concerned that more typical spillway shutdowns would make matters worse and cause more of the crumbling spillway concrete to wash away.
During the crisis, the National Marine Fisheries Service urged state dam operators to ramp down the releases more gradually to protect Chinook salmon, sturgeon, steelhead and other fish. The state declined. Starting on Feb. 28, state biologists in a fleet of boats spent several days rescuing stranded fish after a rapid spillway shut off. They returned nearly 4,000 fish, including 24 endangered and threatened salmon, to the river. It’s not clear how many were dead by the time the biologists found them or how many fish they missed.
The state’s fish-rescue efforts became less frequent as the spring went on, in part because of staffing issues and partly because biologists said they were finding fewer fish. By that point, biologists said, most of the most imperiled species likely were well on their way to the ocean.
State officials say they struck the right balance given the chaotic circumstances. During the worst of the crisis, officials say they tried to keep river levels as stable as they could by releasing additional water from a small downstream reservoir connected to the Feather River. The releases also became much less abrupt later in the season, once workers were able to clear out the massive pile of spillway debris from the channel directly below the dam. The huge rock pile had been blocking the dam’s power plant, which is used to release water from Oroville most of the year.
It’s not clear whether more fish died than normal this year since “this has been a bumper year for Feather River fish migration, especially for young salmon,” Oroville Dam spokeswoman Erin Mellon said in an email.
Mellon said the state is studying whether the debris in the river is lowering channel capacity, and is looking into whether certain landowners should be compensated. But she said new debris and sandbars would be expected in any river channel after the soaking Northern California received this season.
“Riverbanks are not levees” she said: “Riverbanks naturally erode and shift.”
River guides such as Stone don’t buy it.
“They say, ‘Erosion is natural. Erosion is natural.’ But this isn’t a natural river,” he said. “It stopped being a natural river when they put the dam in.”
Farmer Phillip Filter, who lost several acres of land along the riverbanks, said he fears more may collapse.
“We’re looking at maybe trying to go to back in and sticking some blackberries and some native trees and get some stuff growing back in (the banks),” he said. “We still have a lot of bare bank. We’re concerned about next year already. ”
State Sen. Jim Nielsen, R-Gerber, and Assemblyman James Gallagher, R-Yuba City, are demanding the state take action. They want the state to pay for dredging work, to shore up the banks for the farmers and remove submerged trees to reduce boating hazards. They’re calling for the state to release more hatchery fish into the river to make up for what they say is lost spawning habitat and for the unknown numbers of fish that died. That, they say, would compensate anglers and river guides for what they say will be likely fewer adult fish returning to the river to spawn in a few years.
“They are absolutely impacted by this,” Nielsen said of the guides. “There is no doubt.”
Jay Lund, the director of the UC Davis Center for Watershed Sciences, said that while he’s sympathetic to the farmers and the anglers, it’s important to consider what the river would have looked like if the dam hadn’t been built and the levees weren’t there.
After every major storm, the river would swell and recede far more regularly, Lund said. Farmers probably wouldn’t be growing trees on the unstable bluffs above the channel, he said. The course of the river also would more regularly meander as the waterway became blocked with sandbars and debris. That, he said, would make it a challenge for boaters such as Stone to navigate, particularly in the summer. Now, releases from the dam keep summer river levels unnaturally high.
“This is the problem with downstream flood control: You make it less likely to erode and you make it less likely to be flooded,” Lund said. “So people start using the land and the river in ways that make it more susceptible to flood damage when you do get floods and you do get fluctuations in water.”