Authorities lifted a three-day mandatory evacuation order in Northern California that had sent nearly 200,000 residents away following fears Oroville Dam's damaged emergency spillway might fail.
Butte County Sheriff Kory Honea was the first to announce the order was lifted at a press conference Tuesday afternoon in Oroville. "We have concluded that it is safe to return," said Honea.
The sheriff said he had received assurances from state and federal experts that the situation was now deemed safe. He said there's still "an evacuation warning" that considers the possibility that there could be future changes in the situation.
Specifically, Honea said engineers had reduced the level of the reservoir below the top of the emergency spillway so the erosion to the area in front of it could be halted.
Further, the sheriff said the massive hole in front of the spillway was thoroughly inspected by federal and state experts and it revealed there was no erosion that compromised the overall integrity of the backup spillway. Also, he maintained that the concrete-lined spillway (even with its own erosion issues) still is able to provide significant outflows and lower lake levels while also reducing the chance of needing to use the emergency spillway.
According to the California Department of Water Resources, other fixes at Oroville Dam — California's second-largest dam — included dropping sacks of rocks into the emergency spillway's crevice to prevent more erosion.
The hole found Sunday in the emergency spillway — essentially a natural hillside of soil, rock and brush — led engineers to shift major water flows away from this unlined channel. The main spillway is damaged from significant concrete erosion but has still been releasing water this week.
Frantic efforts continue to shore up the emergency spillway before a major storm reaches the Oroville area.
"A lot of equipment and a lot of materials are moving around — from the ground and the air," said William Croyle, DWR's acting director. "This is an aggressive, proactive attack to address the erosion concern."
Speaking at the Tuesday afternoon press conference, the official said about 30 tons of rock per hour are being placed representing about 40 truckloads an hour. Also, two helicopters continue to drop rocks every couple of minutes.
A total of three counties, Butte, Sutter and Yuba, had communities under the evacuation order. Oroville, located in Butte County, is about 70 miles north of Sacramento.
Even with the evacuation lifted, a major storm system is forecast to reach the region within 48 hours and could produce significant precipitation for Northern California and the Oroville area. The storm had been expected to reach Oroville late Wednesday but now forecasters say it will likely be Thursday and stick around through next week.
Residents faced traffic problems after the evacuation order went out and authorities said they are preparing to handle thousands of people returning. There were hints the evacuation would be lifted when people spotted road blocks being removed just after noon Tuesday.
Some of the evacuees have been staying at about a dozen shelters established in the region, including the fairgrounds in Chico, while others fled to hotels in locations such as Sacramento.
There have been concerns about Oroville Dam safety since the erosion of the primary spillway was discovered a week ago. Officials have insisted the dam itself is not at risk.
Last week, claims surfaced that state and federal officials failed to heed safety warnings about Oroville more than a decade ago. The Oroville Dam — the nation's largest earthen dam — was completed in the late 1960s when Ronald Reagan was governor of California.
On Monday, the Federal Energy Regulatory Commission ordered the the state water agency "to initiate immediate design of emergency repair to minimize further degradation of both the emergency spillway and the service spillway."
Croyle, the acting director of DWR, defended the dam's emergency spillway design saying it was "built to the standards at the time [in the 1960s]. We are reviewing that information now."
Speaking late Monday, Gov. Jerry Brown too defended the state's handling of the dam spillway crisis and welcomed more scrutiny.
Meantime, Brown late Monday requested federal assistance from President Donald Trump for the Oroville Dam incident. That request is still pending approval from the president.
Even so, during a press briefing Tuesday, White House Press Secretary Sean Spicer said the president was "keeping a close eye" on the dam situation in California.
While Spicer didn't say whether Trump would grant an emergency declaration, the presidential spokesman said "we will be working alongside with FEMA and appropriate government entities to make sure that we are doing everything we can to attend to this matter."
