The dam burst on a warm afternoon, unleashing nearly 300 million gallons of muddy water on a Los Angeles neighborhood. Five people died and dozens of homes were swept off their foundations and destroyed. In the aftermath of the 1963 Baldwin Hills Dam catastrophe, the state strengthened inspection regulations, helping establish California as a modern leader in dam safety.
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.
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.
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.
Communities just downstream of California’s Lake Oroville dam would not receive adequate warning or time for evacuations if the 770-foot-tall dam itself — rather than its spillways — were to abruptly fail, the state water agency that operates the nation’s tallest dam repeatedly advised federal regulators a half-decade ago. The state Department of Water Resources informed federal dam regulators that local emergency officials “do not believe there is enough time to perform evacuations in the communities immediately downstream of the dam during a sudden failure,” according to a Feb. 8, 2011, letter reviewed by The Associated Press.
Starved of freshwater inflow from the Central Valley rivers that feed it, the San Francisco Bay-Delta is on the verge of collapse. This iconic estuary, which defines our region, has been neglected for too long. Fortunately, the state Water Board is poised to provide relief by updating the Bay Delta Water Quality Control Plan. Phase 1 of the plan calls for requiring 40 percent of unimpaired flow (what would occur in the absence of dams and diversions) between February and June on the lower San Joaquin River and its three major tributaries.
In fall of 2013, Protect Our Water Rights (POWR), a group of North County landowners, united to, “protect its members’ legally predominant rights to reasonably use the water beneath their lands.” After three years of litigation, the window for landowners to join the lawsuit as part of the POWR group is closing.
These three graphs show key California reservoir conditions and river stages for the upper and lower Sacramento Valley. The images are from the California Department of Water Resources’ Data Exchange Center and the National Weather Service.
