How did a giant, gaping hole tear through the massive Oroville Dam’s main concrete spillway last week, setting in motion the chain of events that could have led to one of America’s deadliest dam failures? Dam experts around the country are focusing on a leading suspect: Tiny bubbles.The prospect is simple, yet terrifying and has been the culprit in a number of near disasters at dams across the globe since engineers discovered it about 50 years ago.
No disaster is entirely natural in our re-engineered state and valley. Owing to our hubris, we humans have a direct hand in them all. We have built cities on earthquake faults, balanced mansions on hillsides that burn in one season and slide into the ocean in the next, and moor boats in marinas where tsunamis are known to strike. Having dammed almost all major rivers in California and many tributaries and creeks, we have constructed entire cities in what a century or 150 years ago was swamp, and made islands of rocks piled on peat.
California is not the only place in the West confronting startling amounts of rain and snow. Drought conditions have declined substantially across the region in recent weeks, with heavy storms replenishing reservoirs and piling fresh powder on ski resorts. Yet there is one place where the precipitation has been particularly welcome and could be transformative: the Colorado River basin, which provides water to nearly 40 million people across seven states.
Cleanup was beginning across Southern California on Saturday after a storm that forecasters billed as the most powerful in years caused flooding on multiple freeways, triggered dramatic mudslides and downed hundreds of trees and power lines. The storm was moving out Saturday morning after dumping record rain in some areas and leaving havoc in its wake. Thousands of Los Angeles County residents remained without power early Saturday, while road crews scrambled to repair sinkholes throughout the area, including one in Studio City that swallowed two vehicles Friday night. No one was injured in the incident.
A powerful atmospheric river storm is bringing rain Friday to much of California, resulting in a flood watch for three counties down south and strong winds to the Bay Area. In Southern California, a flash flood watch will be in effect from 7 a.m. Friday through Saturday morning for Santa Barbara, Ventura and Los Angeles counties, according to the National Weather Service. The weather service has issued a high wind warning for parts of the Bay Area and Central Coast, including the Monterey Bay area.
Since going over capacity last week, the water level in the Oroville Dam has dropped, but it’s still at a higher level for this time of year than the previous 16 years. The dam reached capacity causing overflowing water to go into two of the dam’s spillways. But damage to those spillways created concern that they would fail and prompted an evacuation of nearly 200,000 people. The lift on the evacuation was announced on Tuesday, but because of projected high levels of precipitation for California this winter, residents are told to remain vigilant.
Snowpack and reservoir levels continued to increase in California, marking another week of improvement for drought conditions across the state. Last week, 47 percent of the state was in drought, but that figure plummeted to 24 percent this week, according to the Drought Monitor report issued Thursday. At this time last year, 94 percent of California was in drought.
The utterly avoidable, terrifying and still potentially catastrophic failures of the spillways of North America’s highest dam – California’s 170 foot, earth-filled Oroville – could, with the right national leadership, awaken America to the urgency of investing in our physical safety and future – our infrastructure.
To live beneath the Oroville Dam requires a certain measure of faith — faith in the engineers who designed the nation’s tallest dam and the construction workers who built it more than a half century ago, and faith in the government agencies that maintain and operate it.
Jeffrey Mount, a leading expert on California water policy, remembers the last time a crisis at the Oroville Dam seemed likely to prompt reform. It was 1997 and the lake risked overflowing, while levees further downstream failed and several people died. “If this doesn’t galvanize action, I don’t know what will,” Mount said he thought at the time. But spring came, the waters receded and no changes came to pass.
The Water News Network is San Diego County’s source for water news and information.
