Environmental groups warned of dangers at Oroville Dam more than a decade ago
JERRY BROWN PUT STATE CASH INTO SOLYNDRA INSTEAD OF INFRASTRUCTURE SAFETY!
Officials were scrambling to fix a failed spillway at the Oroville Dam in Northern California on Tuesday, Feb. 14, 2017. Sarah Litz/RGJ
Water continues to rush out of a damaged spillway at the Oroville Dam. Evacuations remain in place for residents downriver. USA TODAY NETWORK
Helicopters are airlifting massive bags of rocks in northern California, attempting to use them to plug the damaged spillway of the Oroville dam. (Feb. 14) AP
A shelter in Chico, California was crowded with residents affected by the mandatory evacuations in place near the Oroville dam. A sheriff said Monday that residents may not be allowed home until a crumbling spillway is fixed. (Feb. 13) AP
Nearly 200,000 people remained under evacuation orders Monday as California authorities try to fix erosion of the emergency spillway at the nation’s tallest dam that could unleash uncontrolled flood waters if it fails. (Feb. 13) AP
The Butte County, Calif. sheriff said Monday that nearly 200 thousand residents may not be allowed to retun to their homes until repairs have been completed on a spillway at the Orville dam. (Feb. 13) AP
Aerial footage shows water gushing down the spillway of Oroville Dam during the same week the spillway collapsed because of damage, causing at least 188,000 people to evacuate the area. USA TODAY NETWORK
Tons of rock are being bagged like gigantic sand bags in an effort to slow the erosion on the spillway at the dam on Lake Oroville after thousands of residents were evacuated downstream from the dam. (Feb. 13) AP
A day after the Oroville Dam crisis forced officials to evacuate downstream communities, the city of Oroville is all but empty. Wochit
Water levels dropped Monday at California’s Lake Oroville, stopping water from spilling over a massive dam’s potentially hazardous emergency spillway after authorities ordered the evacuation of nearly 200,000 people from towns lying below. (Feb. 13) AP
Nearly 200,000 people remained under evacuation orders in Northern California Monday, as water pours through a dam spillway, threatining a number of cities. (Feb. 13) AP
Correction: An earlier version of this video misstated the location. California officials are working feverishly to relieve pressure to California’s Oroville Dam to slow the water flow. USA TODAY NETWORK
California’s been hurting for rain the last few years.. but some scientists say they should get ready for a flood of biblical proportions. Josh King has the story (@abridgetoland). Buzz60
Water could pour over an emergency spillway at Lake Oroville for the first time ever, a last-ditch alternative that California officials said they had been hoping to avoid. (Feb. 10) AP
The latest storm in the wet California winter triggered street flooding and rockslides around the San Francisco Bay Area. South of San Francisco, one of several rock and mudslides overturned a pickup truck on a state route near Santa Cruz. (Feb. 7) AP
Watch: Oroville Dam crisis update
Chopper flies over damaged spillway at Oroville Dam
Raw: Rocks Used to Plug California Dam Spillway
Residents Wait-Out Dam Emergency in Shelters
Raw: Video shows water gush through dam spillway
Ca. evacuation may not end until dam fixes made
See water gushing out of the Oroville Dam from the air
Raw: Crews work to shore up spillway at Oroville
Oroville is a ghost town
Officials assess water damage at Oroville dam
Nearly 200,000 told to evacuate from dam area
Damaged dam threatens to unleash uncontrolled floodwaters
California may be in for a massive flood
200-foot-long hole in damaged Calif. dam
Raw: New Calif. storm brings flooding, mudslides
In 2005, three environmental groups raised concerns that the emergency spillway at California’s Oroville Dam wasn’t properly built and posed serious risks.
The groups – Friends of the River, Sierra Club and the South Yuba River Citizen’s League – described their worries in a motion to the Federal Energy Regulatory Commission, which was considering the dam’s relicensing.
The environmentalists wanted federal officials to require modifications including building a concrete-armored spillway rather than leaving it a concrete “lip” above an unprotected hillside prone to erosion damage. They warned that given the spillway’s design, possible uncontrolled floodwaters “could not only cause additional damage to project lands and facilities but also cause damages and threaten lives in the protected floodplain downstream.”
State officials who manage the dam dismissed those concerns at the time, and federal regulators are still considering the license renewal. But the warnings aired more than a decade ago have turned out to be well-founded, as officials have ordered entire towns evacuated and Gov. Jerry Brown has declared an emergency.
Ron Stork, a senior policy advocate with Friends of the River, said the current emergency is precisely what he had feared.
“Our combined judgement at the time was that the Oroville Dam complex could not be used safely or confidently to conduct flood control operations,” Stork said in an interview Monday. He said the environmental groups had demanded “a proper spillway.”
“There isn’t one. It’s a spillway lip, a little bump on the top of a hill,” Stork said, explaining that having the bare hillside below the emergency spillway allows for major erosion damage to the hillside when water pours over as it did on Sunday.
Oroville Dam, which stands 770 feet high, is the tallest in the United States. It’s also California’s second-largest reservoir, after Shasta Lake, and the largest in the State Water Project, a network of canals and pumping stations that move water from Northern California to the Central Valley and Southern California. It’s one of the key reservoirs in the system that stores water for the dry spring and summer months.
Building a concrete-armored spillway would have required water districts that rely on the State Water Project to absorb some increases in the costs of water, and Stork said they didn’t want to do that at the time.
“They didn’t want to pay for a second spillway, which almost failed last night,” Stork said. And as for state regulators, he said, “what they said is that the existing spillway is safe.”
The environmental groups’ warnings about the dam’s emergency spillway were first reported by the San Jose Mercury News.
John Onderdonk, a senior civil engineer in the Federal Energy Regulatory Commission’s Division of Dam Safety and Inspections, responded to the concerns in a memo on July 27, 2006, saying the emergency spillway’s design complied with the commission’s engineering guidelines.
“Our evaluation indicates that, in the rare event of a discharge, the emergency spillway would perform as designed,” Onderdonk wrote. “Emergency spillway flows would flow down a channel consisting of soil, bushes, and trees covering bedrock. Erosion of one to four feet of soil cover, and debris flow… would occur during a large release in the emergency spillway.”
He pointed out, however, that flows down the spillway would be directed away from the dam itself and “would not affect reservoir control or endanger the dam.”
The hydroelectric dam’s federal license expired on Jan. 31, 2007. Since then, the California Department of Water Resources has operated the dam under temporary annual licenses issued by the Federal Energy Regulatory Commission.
“The relicensing process requires a variety of state and federal agencies to issue permits and other documents,” said Celeste Miller, a spokesperson for the federal commission. “We have just, in December 2016, received all the necessary permits and other documents we need before issuing a final decision on the application.”
According to a state dam safety report, the most recent inspection of Oroville’s main spillway didn’t include a close examination of the structure. The July 2015 report by the Division of Safety of Dams states that “a visual inspection from some distance indicated no visible signs of concrete deficiencies.”
Chris Orrock, a spokesperson for the division, said it was unclear why the dam spillway was not more closely inspected.
Oroville Dam, located in the Sierra foothills east of the Sacramento Valley, was completed in 1968 – a middle-aged reservoir in a state where many other dams were built between the 1920s and 1950s.
The reservoir rose rapidly this winter as the Feather River and its tributaries gushed down swollen after heavy rain and snow. The storms, which came after more than five years of severe drought, have led officials to release water from various dams across Northern California.
A gaping hole appeared in Oroville Dam’s main spillway last week, and then water began pouring over the emergency spillway for the first time in the reservoir’s history.
While the dam itself remained intact, erosion damage to the emergency spillway over the weekend raised the potential of the structure failing and unleashing a dangerous torrent of floodwaters.
Trying to head off a disaster, state officials increased the flow down the main spillway on Sunday night, and on Monday the lake’s level was dropping. The town of Oroville and other communities downstream remained under evacuation orders due to the threat of flooding.
Officials said they hoped their increased use of the main spillway would help save the backup spillway. They used helicopters on Monday to drop boulders into damaged areas of the emergency spillway.
More storms are headed for California this week, and forecasters say they will be strong enough to bring 2 to 6 inches of rain to Oroville.
Michael Dettinger, a hydrologist with the U.S. Geological Survey, said the coming storms plus the heavy snowpack in the mountains above the reservoir make for an emergency that won’t ease anytime soon.
“The real tension now comes from the fact that we still have as much as another 6 weeks’ worth of on-again-off-again storminess… before we are likely to be able to breathe calmly about the kind of situation we saw at Oroville this weekend,” Dettinger said. “That’s a lot of opportunities for another big storm or storm sequence to show up, and all the outlets at Oroville are pretty much limping at this point.”