For the past week, the residents and authorities of Oroville, Calif., have been dealing with an unusual problem for the Golden State: too much water. On Feb. 11, the Oroville Dam reached its 901-foot capacity and began to overflow as a result of winter storms. After a tense week of frenzied attempts to release excess water via emergency spillways, evacuated residents are allowed to return to their homes as flood levels slowly decrease. As of Monday, the California Department of Water Resources had successfully lowered the water level to their goal of 50 feet below capacity.
Though the situation has stabilized, Oroville’s problems are not over. Last week’s flooding called into question the stability of the dam system. Engineers discovered a massive hole in the dam’s primary spillway as water levels began to rise in early February, and the secondary spillway began to erode soon after engineers put it into use as an emergency last resort. This secondary spillway had never been used in the dam’s nearly 50-year history, and water flow was quickly shifted back to the primary spillway after the erosion began.
Another round of rain early this week was successfully drained from the reservoir with no further damage to the spillway; currently, the flow of water out of the dam is under control — the question is now whether the spillways will be able to withstand another similar situation.
Completed in 1968, the Oroville Dam is the tallest in the United States and is, according to some, only one symptom of a larger problem concerning U.S. dam safety and maintenance. Many of the country’s major dams are in need of repair. The Oroville dam is one of many that certain activists and lawmakers say have suffered from chronic underinvestment in recent decades. But it provides a challenge of uniquely large scope.
“What would be different if the Oroville dam collapsed is that it would previous U.S. dam disasters look small in comparison,” Aten said.
According to Aten, some models project the collapse of the Oroville dam unleashing a surge of water with waves 30 feet high; by comparison, Hurricane Katrina’s largest waves were just 28 feet high.
“Overall, significantly more people live in harm’s ways of the Oroville site,” Aten said. “The body of water and wave surge that could be unleashed would dwarf the previous events.”
The Oroville crisis is the same challenge that California has been facing for years — how to manage water — but this time, it’s a matter of excess, rather than scarcity. And for the thousands of people who are living in harm’s way, it raises questions of life and death.
If the spillway collapses, billions of gallons of water contained in the Oroville Reservoir would rush into the Feather River valley, destroy countless towns between Oroville and Sacramento, displacing nearly hundreds of thousands of people, and eliminating the primary water source for much of Southern California and the Bay Area. The reservoir also supplies the water for agriculture in the Central Valley. A collapse could lead to crop failure in the region with the largest supply of many nuts, fruits and vegetables in the U.S.
The destructive potential of the dam is a pressing reality for the nearly 200,000 residents who were ordered to evacuate on Feb. 12 and are now returning to their homes. Phoebe Silva, a freshman who lives less than two hours from the dam, experienced the pressure of this realization firsthand.
“I was in panic ,” Silva said. “If the dam broke my town would be partially flooded but the town next to me would be completely. … Basically all the people from my high school and church and everyone I knew and grew up with were in harm’s way.”
Being removed from the situation made the stress even worse for Silva.
“I was so worried, especially because … people were posting mixed messages,” Silva said. “College students who were away were freaking out because we did not know what was true.”
According to Dr. Jamie Aten, co-director of Wheaton’s Humanitarian Disaster Institute, the evacuees themselves in situations like the one in Oroville face not only the emotional stress that comes from the act of evacuating, but also the stress from the what-if scenarios afterwards.
“Even though many of the people ordered to evacuate have been able to return home, many of the evacuees are likely still experiencing a high degree of stress,” Aten said. “Such situations can turn abstract theoretical scenarios into real life possibilities which can make people feel vulnerable. This sort of event can also start to raise people’s’ awareness of their mortality, which tends to add to the stress.”