Skip to content Skip to navigation

Days That Nearly Brought Disaster to the Oroville Dam

Feb 14 2017

The surface of Lake Oroville on Feb. 7, just as problems were appearing on Oroville Dam's main spillway below. California Department of Water Resources

By Geoff McGhee

California avoided a major catastrophe in the past week as heavy rains compromised the 700-foot Oroville dam. As the Los Angeles Times explained, a rift gouged by water spilling over the dam was eroding a hill supporting one of the dam's walls. Uncontrolled releases would have inundated communities in the valley below. Public safety officials called for a mass evacuation of towns downstream. Here is a day-by-day account of what happened and what state engineers and safety officials did.

Tuesday, Feb. 7: "An Unusual Flow Pattern" Discovered


"DWR halts flows down Oroville Dam spillway. Engineers investigating erosion." California Department of Water Resources

Around midday, while releasing water from Lake Oroville, dam operators notice "an unusual flow pattern and erosion" on a concrete chute designed to channel water into the Feather River.

Operators close the gates of the spillway to halt the flow and inspect the dam.

Photos taken at the time by the Department of Water Resources show a jagged gouge in the concrete bed. In a comprehensive blog post, the earth scientist Dave Petley describes the cavity as "extraordinary erosion" and "major damage.” Petley is based at the University of Sheffield in England.

Losing the use of the chute during a period of strong rains deprives the operators of a key tool for maintaining reservoir levels and delivering irrigation water supplies as far as southern California.

Lake Oroville, which provides nearly two-thirds of the supplies delivered by the state water project, starts the day at at 80 percent of capacity, holding about 2.8 million acre-feet of water. The California Department of Water Resources (DWR) estimates that the reservoir has room for three more days of inflows, and that "there is no anticipated threat to the public."

Ending Reservoir level: 862 feet

Wednesday, Feb. 8: Tests Further Erode Main Outlet


"DWR continues to assess the concrete erosion on the Oroville Dam spillway. No imminent threat to the dam or public." California Department of Water Resources

As Lake Oroville continues to rise from storm runoff on Wednesday afternoon, operators attempt a test flow on the damaged main spillway. DWR warns that this test is "expected to further erode the lower reach of the spillway." After the test, Petley writes, "Unsurprisingly, the condition of the spillway has dramatically deteriorated."

Operators continue to release water through the main spillway, but at a reduced rate of 20,000 cubic feet per second, one fifth as fast as water is entering the reservoir.

By the end of the day, the reservoir's level is within 25 feet of the rim. The dam was designed with a notch in its rim so that when it is full, water will begin to pour down a hillside called the "emergency spillway." This safety valve has never been used.

Toward the end of the day, operators increase the outflow rate to 65,000 cubic feet per second on the main spillway.

Reservoir level: 875 feet

Thursday, Feb. 9: Focus Turns to Never-Used Emergency Spillway

At about 6pm, inflows peak at 190,000 cubic feet per second and Lake Oroville inches closer to overflowing.

Unlike the concrete-lined main spillway, the secondary spillway's earthen hillside is dotted with trees and shrubs; allowing water to run down it will carry large amounts of debris into the Feather River. Water flowing over this hillside is essentially uncontrolled. Workers, aided by Cal Fire crews, begin to remove trees and brush. Fish and eggs are moved from a downstream hatchery to a safer location.

The Department of Water Resources begins emergency planning in coordination with a number of state and federal agencies, from wildlife services to Cal Fire.

DWR announces, "Oroville Dam itself is sound and there is no imminent threat to the public."

Reservoir level: 890 feet

Friday, Feb. 10: Reservoir Levels Climb


"DWR monitoring Oroville around the clock. Lake levels expected to drop thruout weekend with outflows of 65KCFS #OrovilleSpillway" California Department of Water Resources

DWR’s acting director, Bill Croyle, tells reporters that "the dam itself is sound and there is no imminent threat to public." DWR and CAL Fire crews continue clearing vegetation from below the emergency spillway.

Reservoir level: 899 feet, two feet below the maximum level

Saturday, Feb. 11: Water Overtops Emergency Spillway


"Flow over auxiliary spillway between 6,000 and 12,000 cfs. No danger to dam or people. #orovillespillway" California Department of Water Resources

Around 8 in the morning, water begins to flow over the emergency spillway for the first time in the dam's 48-year existence; levels had come within a foot of this point during January 1997 storms.

DWR reports that the secondary spillway is carrying 5,000-10,000 cubic feet per second. This amount, combined with the releases from the main spillway, sends as much as 70,000 cfs to the Feather River.

The department's director says that damage to the main spillway is so extensive that it will have to be rebuilt at a cost of as much as $200 million. Aerial photos show torrents of water cascading from the lake and ricocheting off both the main spillway and the earthen face of the dam.

Reservoir level: 902.5 feet, a foot and a half above the crest of the emergency spillway weir.

Sunday, Feb. 12: Emergency Spillway Erodes, and Evacuations Are Ordered

Screen shot from KCRA TV coverage
Screen shot of television coverage by KCRA TV Sacramento KCRA

Evacuation Alert from National Weather Service
Evacuation Alert from National Weather Service National Weather Service Sacramento

Flash Flood Alert from National Weather Service
Evacuation Alert from National Weather Service National Weather Service Sacramento

Overnight, water releases overtake stormwater inflow and the reservoir's level starts to drop.

In the morning, crews work to clear debris from the bottom of the main spillway so that the Edward Hyatt power station, with six generators underground near the dam, can restart and pump more water from Lake Oroville.

By mid-afternoon, DWR says that flows over the emergency spillway are declining. The dam, they say, is stabilizing. The San Francisco Chronicle reports that "so far, the emergency spillway has worked as designed."

Later, though, DWR discovers erosion at the top of the emergency spillway. The flow on the main spillway is doubled to 100,000 cfs to reduce strain on a concrete weir atop the emergency outlet; its failure, says DWR, could lead to uncontrolled flooding.

Around 5 P.M., evacuation orders are issued for residents of Oroville, which sits several miles downstream, and other communities as far south as Gridley, 16 miles away. Evacuation orders eventually affect more than 200,000 people in Butte, Yuba, and Sutter counties.

Reservoir level: 900 feet

Monday, Feb. 13: Urgent Repairs


"Efforts are underway to make repairs to both the primary and auxiliary spillways at Lake Oroville." California Department of Water Resources

On Monday morning, the dam continues to release 100,000 cfs through the main spillway, and efforts continue to restart the power plant. DWR maintains that this rate of water release is consistent for the time of year, and reservoir levels are down to 894 feet by 5pm.

DWR is using helicopters and earth-moving equipment to shore up the rim of the emergency spillway with rocks.

The evacuation order remains in effect through Wednesday, giving crews time to examine the dam and begin repairs before new storms enter the area. Beginning with The San Jose Mercury News, reports surface that dam managers have known for years, even decades, that the emergency spillway design was potentially flawed.

Weather forecasters predict five days of new rain in the area, beginning Thursday.

Reservoir level: 894 feet

Tuesday, Feb. 14: Evacuations Downgraded

Map of counties with evacuation orders on Feb. 12
Bill Lane Center for the American West

On Tuesday afternoon, Butte County Sheriff Korey Honea announces that the mandatory evacuation affecting 188,000 people has been lifted. While he says that residents should remain alert for new warnings, officials are confident in repairs to the area around the emergency spillway.

Levels on Lake Oroville continue to decline, as DWR acting director Bill Croyle predicts that oncoming storms will be weaker than the previous week's and will bring less water to the area. DWR officials say that their goal is to lower Lake Oroville by 20 to 50 feet below the rim before the storms arrive on Thursday.

At the national level, the Trump administration says that it is keeping "a close eye" on developments at Oroville Dam, after Gov. Jerry Brown on Monday calls for federal assistance for Butte, Sutter, and Yuba counties.

Reservoir level, as of 3pm: 887 feet

 

Read Next in ...& the West

The Southwest’s Orphan Disease Thrives on Ignorance

Valley Fever, a lung disease born of invasive fungal spores that are carried on clouds of swirling dust, is the best-known medical secret of the American Southwest. The parts of California and Arizona where the fungal spores flourish are once-rural places that are now population magnets, where new construction disturbs the earth and can send spores flying.

 

Submit a Comment

We'd like to know what you think. We will not share your email address or add you to any lists. If you'd like to be notified about new blog posts and news from the Center, you can join our mailing list.

You will receive emails no more than once a week. We will not share your information.

 

...& the Best

Western Articles and Media Elsewhere
Compiled by Felicity Barringer and Carolyn P. Rice

Articles Worth Reading: Feb. 25, 2019

Dramatically Cutting Back Irrigated Farming in California’s Central Valley is required to replenish overdrafted groundwater, says an in-depth report from the Public Policy Institute of California. The changes needed to restore aquifers will require fallowing 500,000 acres of irrigated cropland. “Although ending overdraft will bring long-term benefits, it entails near-term costs...Only a quarter of the Valley’s groundwater deficit can be filled with new supplies at prices farmers can afford,” the authors write. They add “the best option for increasing supply is capturing and storing additional water from big storms.” Fresno Bee Public Policy Institute of California

The Senate Approved the Natural Resources Management Act expanding existing public lands, creating new national monuments, protecting miles of rivers from development, and preventing mining around Yellowstone and North Cascades National Parks. Controversies arose over a provision that could allow the return of hundreds of thousands of acres of federal land to Alaska Natives. These brought into clearer view the different priorities and fraught history of conservationists and Indigenous peoples. The Washington Post The Guardian The Washington Post (Op-Ed) High Country News

Representatives From the Quinault and Tohono O’odham Nations, the Calista Corporation, and Heartlands International Spoke About the Ongoing Impact of Climate Change on Native communities. The House Natural Resources Committee’s new subcommittee for indigenous peoples of the United States, in its first punlic meeting, heard how changing seasons and rainfall are altering growing seasons, food availability, and by extension, affecting cultural practices. Low-lying communities are particularly vulnerable to changes in precipitation and sea-level rise. The Arizona Mirror YouTube

A Multi-Part Exploration of the Colorado River’s Challenges Ends With an Ode to the River’s Former Wildness and a look at restoration efforts. Today, the Colorado River is a highly engineered river, plagued by invasive species of plants and fish. Some of its most biodiverse regions are man-made, and their future hangs in the balance with the future of water. Yale Environment 360

Across the Western U.S., Thousands of Cacti and Succulents Have Been Stolen From Public Lands. The market for these plants is lucrative, and rare species attract the attention of collectors and thieves. Removing the plants from their habitats can limit their chances of survival and endanger the remaining individuals. Even though thieves face felony charges and thousands of dollars in fines, the illegal trade continues. Innovative attempts to curb the poaching include cloning succulents and microchipping saguaros. The New Yorker The Guardian

Articles Worth Reading: Feb. 11, 2019

New Restrictions on Colorado River Withdrawals in Dry Times Are Close, but the federal Bureau of Reclamation says, in effect, “close only counts in the game of horseshoes.” The Arizona state legislature met the bureau’s deadline as it agreed to the drought contingency plan formulated by all three states in the river’s lower basin, but the final deals with Native tribes and with California’s Imperial Irrigation District aren’t done yet. The arguments go on. Cronkite News

Native Trout Are Making a Comeback in Colorado, but It’s Taken Decades. As the West was colonized, so were its streams; native fish suffered as non-native ones were introduced. The native greenback cutthroat trout was mistakenly declared extinct in 1937, but its history turns out to be much more complicated. Today, the subspecies survives, but barely, and scientists do not agree on a solution for the fish’s future. Biographic

Ranchers in Montana Want Consumers to Know Where Beef Comes From. The U.S. imports roughly 10 percent of its beef -- from countries like Canada, Argentina and Uruguay -- but it doesn’t have to be labeled as such. Country of origin labeling, Montana ranchers argue, will help consumers make more informed choices--and think it will be good for business. If passed, a bill in the Montana State Senate would require this labeling, as well as prohibit labeling as “meat” the cell-based meat now grown in vitro in laboratories. That decision which could be detrimental to this nascent industry. Civil Eats

Sustainable Development and Gentrification Do Not Have to Go Hand in Hand. An affordable housing project in an industrial, low-income neighborhood of Portland could show the country how green infrastructure can help alleviate poverty and keep communities intact. This project includes weatherization of mobile homes and sustainable landscaping. High Country News

We Need Maps to Comprehend the Scale of the Grand Canyon. Be careful, though–some maps are more attractive than they are accurate. As the iconic national park’s 100th anniversary approaches, listen to the Science Friday podcast explore the history of Western mapmaking through the lens of the maps of the Grand Canyon. Science Friday

Art Installations Thrive in the Coachella Valley. Desert X, a biennial art exhibit, opened this past weekend. It showcases art in mediums that range from fabric to cell phone, all to connect people with the valley and its human history. Explore some of the installations in this photo gallery. The Desert Sun

Articles Worth Reading: Jan. 28, 2019

Wildfires Can Cause Thunderstorms, and the world is witnessing more of these as fires become more common and more intense. Scientists still struggle to understand the exact mechanisms behind the storms, but the effects have become clearer. Lightning can spark additional fires, and winds can hamper firefighting efforts. Particles and gases in the clouds can affect weather patterns on the same scale as small volcanoes. Mother Jones

A Surprising Source of Pollution Sits on the Ocean Floor off of California’s Central Coast: Golf Balls. The little spheres from coastal golf courses release chemical pollutants and break down into bits of plastic that can enter the food chain. A local teenager and a Stanford University scientist found and began to remove golf balls from the waters off of Pebble Beach by the thousands, but more keep falling in. NPR

Mapping as a Way of Creating Indigenous Dialogue Around Place and Art: Jim Enote, an indigenous farmer and museum director, says that because most maps use colonial names, borders, and ideas of space, expanding the definition of maps has been a necessary part of his process. National Geographic

Decrepit Dams in Washington State May Flood Towns Downstream. A recent wildfire made the landscape more prone to runoff, and the dams cannot store the increased winter rainfall associated with a warmer climate. Attempts to repair and modify the dams have highlighted the financial and political challenges of managing remote wilderness. as local agriculture and salmon habitat rely on the shrinking summer water supply. The Seattle Times

Animals From Insects to Wolves May Suffer From Construction Along the U.S.-Mexico Border. Physical barriers and habitat loss can separate animal populations and limit migration. Over 1,500 native plants and animals in the region could be affected by construction of a wall, according to a 2018 report signed by nearly 3,000 scientists. The New York Times

Articles Worth Reading: Jan. 15, 2019

Pacific Northwest Farmers Have Silos Full of Unsold Legumes. The price of garbanzo beans fell by more than half after changes to U.S. trade policy and sanctions on China last year reduced exports. Farmers had already expanded their production, and now they must find a way to pay their debts. Oregon Public Broadcasting

The City of Spokane Is Trying to Clean Up Its Groundwater, which has been polluted by industrial toxins since World War II. Washington state has recently increased the strictness of its water quality standards, but implementation of these standards faces financial, political, and technological challenges. The pollution has accumulated to dangerous levels in the Spokane River fish, which is of particular consequence to the diet and health of the indigenous Spokane people. High Country News

Is Hunting Elk Out of Season Illegal for A Member of the Crow (Apsáalooke) Tribe? The state of Wyoming imprisoned Clayvin Herrera for hunting elk, but the Crow argue that the conviction violates their treaty with the U.S. The case of Herrera v. Wyoming was heard in the Supreme Court last week, and it draws attention to the complexities and contradictions of legal relationships between the U.S. and tribal nations. The Atlantic

Phoenix Has a Public Health Crisis: Heat. Hot days are more frequent, temperatures are rising with climate change, and more than 155 heat-related deaths happened last summer in Phoenix. The city is searching for ways to keep cool during the summer, including umbrellas, text alerts, and creating more shade. The groups that suffer the most, however, are those with the least ability to change their circumstances: low-income communities and the elderly. NPR

Scientists Are Collecting Pictures of Snowflakes from School Children to Analyze Snow Formation and Weather Patterns. Students in the Sierra Nevada can use their phones to take photos of snowflakes and upload them to a citizen science database. Compared to other technologies, this is a more efficient and less expensive means of collecting data on snow conditions, and it gives students the opportunity to learn about research. Science Friday

Articles Worth Reading: Jan. 7, 2019

National Park Life in a Shutdown Situation Means No Snowplows, Few Toilets and Overflowing Trash. Now the Interior Department is taking the unprecedented step of using entrance fees to pay for basic housekeeping – a use that may contravene the mandates of Congress. Around the system, operations are ad hoc. With fresh snow covering the roads and no personnel available to plow them, Arches and Canyonlands national parks shut their gates a week ago as the federal government’s partial shutdown ground headed into its third week. Utah has been funding some personnel costs, but that money was being used to staff visitor centers and clean toilets, not clear roads. In other states, nonprofits, businesses and state governments put up money and volunteer hours to keep parks safe and clean. But makeshift arrangements haven’t prevented some parks from closing and others from being inundated with trash, hence the move to repurpose visitor fees. Salt Lake Tribune Washington Post

After Years of Increasingly Inadequate Fire-fighting Budgets, a Fix Passed by Congress Takes Effect later this year creating a $2.25 billion emergency fund federal officials can use when firefighting costs exceed the firefighting budget. The head of the forest service said it can now better plan when responding to catastrophic fires. Under the fix, the annual firefighting budget would remain at a little more than $1 billion per year, but in fiscal 2020 – which begins Oct. 1 – there will be $2.25 billion to fund operations once the regular fund is spent. The emergency fund would grow by $100 million a year, reaching $2.95 billion in fiscal 2027. ASU/Cronkite News

Banning Heights, a Tiny Central Valley Town, Has an Inadequate Water Supply using broken infrastructure; the private utility responsible for maintaining it has failed to do so. For years, residents in this rural enclave tucked above the Interstate 10 freeway have tried to make Southern California Edison repair century-old pipes taking water from San Gorgonio mountains to their homes. Last year the local water company spent $178,000 ensuring adequate flow for basic health, sanitation and firefighting. Meanwhile, water continued to flow above the community from the Whitewater River, pouring out of unrepaired pipes and around deteriorating dams; 98 million gallons leaked into the dirt during fire season. For 15 years, the utility has tried to surrender its license for the hydroelectric system to the Federal Energy Regulatory Commission. FERC, Banning Heights and the city of Banning say: fix the system first. Desert Sun

The Pacific Northwest Once Boasted Widespread Beaver-Built Salmon Habitat. Now the Tulalip tribes are trying to bring the beaver dams back. After Europeans decimated most of the 400 million beaverds they found in North America, beaver dams crumbled and the ponds and streams slowly disappeared. So did the salmon they supported. More recently, the sentiment that Castor canadensis is a tree-felling, water-stealing, property-flooding pest dominated state agencies in Washington, Oregon and California. But many scientists and land managers are discovering beavers can serve as agents of water conservation, habitat creation, and stream restoration – not to mention groundwater recharge. In Washington, a revised Beaver Bill allows beaver relocations on both sides of the mountains, sailed through. Starting this year, non-tribal groups, like environmental nonprofits, will be able to relocate the animals. BioGraphic

Is It Time to Start Eating Roadkill in Places Outside Alaska? Every year, between 600 and 800 moose are killed in Alaska by cars, leaving up to 250,000 pounds of organic, free-range meat on the road. State troopers who respond to these collisions keep a list of charities and families who have agreed to drive to the scene of an accident at any time, in any weather, to haul away and butcher the body. “It goes back to the traditions of Alaskans: We’re really good at using our resources,” Alaska State Trooper David Lorring said. The state;s tradition of making do means it would be embarrassing to waste the meat. In the past few years, a handful of states, including Washington, Oregon and Montana, have started to adopt the attitude that Alaskans have always had toward eating roadkill. A loosening of class stigma and the questionable ethics and economics of leaving dinner to rot by the roadside have driven acceptance of the practice in the Lower 48. High Country News

Articles Worth Reading: Dec. 17, 2018

Pollution on the California-Mexico Border, Some Carried by the New River, flows though the region. Some of it wafts through the air that carries factory fumes over Mexico and Calexico, Some rises from fetid garbage dumps. It all does serious harm to the health of local residents. A series of articles show smokestacks, traffic exhaust, dust, and smoke from trash fires, often leave the cities blanketed in hazy air. The pollution is linked to high rates of respiratory illnesses and deaths. The Desert Sun

We Knew the California Snowpack Was Declining. Now We Know How Fast: 79 Percent by the century’s end. As it fades, much less snowmelt can be drawn on to fill huge reservoirs such as Shasta, Oroville and Folsom. All this as the state’s population and farm economy continue to grow. The new reality that will require fundamental changes in the way California and the federal government have operated the state’s water system for nearly 100 years. San Jose Mercury-News

In Sacramento, Two New Decisions on Dividing the Waters. In one, the state’s top water agency decides to send more water to Delta fish populations on the San Joaquin River, angering farmers and cities. In another, the governor defers to the federal government and makes more water available to farmers. Sacramento Bee
Sacramento Bee

A Federal Ultimatum Declared on a Colorado River drought contingency plan. Get it done by January 31, said the Bureau of Reclamation Representative told the seven states negotiating the plan — or we’ll do it for you. California and Arizona are the last states to fall into line. But this plan, when it is final, could be a bridge to another agreement to manage the water world of the Southwest as the climate changes and the water disappears. Also: how to think about the future. Denver Post Cronkite News John Fleck

Big Utilities Plan Power Shutoffs to Avoid Sparking Wildfires, while the experience of the Camp Fire indicates that small local power grids enhance the resilience of areas in the wildland-urban interface. Utility Drive

Should Washington State Breach Dams to Preserve Orcas? The decline of Puget Sound’s orca population has many probable causes: toxins in the water, noise from boats and lack of food. Chinook salmon are its primary food, and salmon runs are feeble, despite tens of millions spent by hydropower authorities to bolster salmon runs. As part of a $1 billion-plus save-the-orca effort, Washington Gov. Jay Inslee unveiled a $750,000 plan to investigate the impact should four Lower Snake River dams be removed. It drew criticism from the northwest’s congressional Republicans. Idaho Statesman

Graphics & the West

Where California Grows Its Food

See the most detailed survey ever done of crops and land use in California. It covers nine million acres of land devoted to grapes, alfalfa, cotton, plums, you name it – food for people and animals all over the world. View map »

California's Changing Energy Mix

A look at the energy sources California utilities have used gives us insights into the state’s progress in decarbonizing its electricity supply. In 2015, 35% of total electricity generation (in-state generation plus imported electricity) came from zero-greenhouse-gas sources, which include solar, wind, hydropower, and nuclear. View Graphic »

U.S. Conservation Easements

Conservation easements of various kinds cover more than 22 million acres of land in the United States, according to the National Conservation Easement Database, a public-private partnership. Take a look at our interactive map of nearly every conservation easement, with details on over 130,000 sites. View map »

 

Recent Center News

Mar 18 2019 | Happenings, ArtsWest
The contributions of all four speakers contributed to the sense of Burning Man as a type of experimental art utopia for those seeking an alternative to purely capitalist pursuits.
Mar 11 2019 | ... & the West Blog, ... & the Best | Posts Recommended by the ... & the West Blog
Grey wolves are recovering and may be taken off of the federal Endangered Species List; mountain caribou conservation has not succeeded in the United States; avalanches ravage the Rockies during the wettest winter on record; the San Joaquin Valley suffocates while it feeds the country; and native bees in Utah host unwelcome houseguests. Explore these latest environmental reads.
Mar 5 2019 | ... & the West Blog
Green power source or fish killer? As older dams around the West come up for relicensing, their owners know that they’ll have to spend heavily to fix problems, while new energy sources are getting cheaper.