By the time you read this on Monday morning, the Oroville Dam in California, holding back the second biggest reservoir in the state, may have been washed out. As of Sunday night, there are flash flood warnings due to an imminent collapse of the auxiliary spillway for low-lying areas downstream of the dam. While the reservoir was below 30 percent of capacity just a couple of years ago due to the long drought there, recent record-setting rain events associated with atmospheric rivers have filled up the reservoir completely and more water is draining into the reservoir from surrounding hillsides. The main spillway from the dam has been damaged and the extra spillway to the left of it is also dumping water from the rising reservoir. But officials fear that the extra spillway is also eroding and could compromise the reservoir. The reservoir is currently full and is holding 1.2 trillion gallons. If this would happen, not only would there be significant loss of life but potential damage to many structures and the loss of years of irrigation water if the worst case happens.
(UPDATE on Monday morning 2/13: Officials have successfully dropped the reservoir levels enough using the main spillway to cut off flow over the auxiliary spillway, allowing them time to repair some of the erosion before the next big storm hits in about a week.)
Fortunately, they have had several sunny days with no rain, so the flow into the reservoir is slacking off and the emergency spillway may stop flowing if the water levels drop. The next storm is expected later this week, giving them a few more days before the next rain enters the watershed. I will praying for the residents and the emergency workers who are dealing with this situation.
You can see photos from the San Francisco Chronicle at https://www.sfgate.com/bayarea/slideshow/Dramatic-photos-Damage-to-Oroville-Dam-spillways-141198.php.
