Hell or High Water? Oroville Dam Spillway Collapse

Helicopters are airlifting massive bags of rocks in northern California, attempting to use them to plug the damaged spillway of the Oroville dam. This includes an emergency kit, a way to communicate with family members and other proactive steps to be prepared.

Meanwhile, in Northern California, the increased precipitation resulted in the evacuation of almost 200,000 residents near the 770-foot Oroville Dam. "This is exactly why planning ahead is essential", said Pat Hogan, senior vice president of Electric Operations at PG&E.

Graph of the Lake Oroville storage levels from 2016- present.

The crisis peaked Sunday, when engineers found the pocket of erosion under the emergency spillway - a concrete wall built to permit overflow when Lake Oroville hits capacity.

Jerry Brown asked the Trump administration for a federal disaster declaration, saying the problems were likely to be more than local and state officials can handle.

Thousands of homes sit abandoned in the Feather River Valley below California's Lake Oroville Dam, as officials race to fix the dam's damaged spillways.

Crews working through the night atop the crippled Oroville Dam have made solid progress in shoring up the damaged emergency spillway, state officials reported Tuesday morning. This led to the evacuation of about 200,000 people, and all of them remain away from their homes, filling Sacramento area hotels as well as campgrounds and community centers to the north around Chico.

At 770 feet (230 meters) high, the structure, built between 1962 and 1968, is the tallest US dam, exceeding the Hoover Dam by more than 40 feet (12 meters).

In total, it's possible that some parts of California, potentially including the area that drains into Lake Oroville, could see up to 9 inches or more of rain in the next seven days.

The emergency spillway suffered severe erosion the day after water cascaded down the unpaved hillside for the first time since the dam opened in 1968.

Much like the Titanic, one can only assume Oroville Dam officials believed their structure was infallible and couldn't be bothered to inspect it, or listen to environmentalists warnings.

Almost three years later, state officials said no "significant concerns" about the emergency spillway's integrity had been raised in any government or independent review.

The main spillway is already damaged and running water started to erode the left bank of the spillway. Image by William Croyle, California Department of Water Resource, work is in the public domain.

At this time experts are not concerned that rising water levels will pose a threat. Brown called the situation in Oroville a "challenge of engineers, on the ground hands-on people who know how to fix the elements of this dam".

  • Jon Douglas