188000 in California Ordered to Evacuate Over Potential Dam System Failure
- Author: Leroy Wright Feb 14, 2017,
Feb 14, 2017, 3:00
The Department of Water Resources said about 3 p.m. Sunday a headcut appeared in the soil downhill from the emergency spillway, and appeared to be spreading upward toward the structure.
The water level in Oroville Lake topped the 901 foot crest by up to 4 inches beginning Saturday, sending 500,000 cubic feet per second (cfs) of water over the earthen dam's mile-long emergency spillway, which had never been activated since the dam, America's tallest, went into operations in 1968.
It's not immediately clear what caused the crack to form, but engineers at the dam were forced to release massive amounts of water over the top of it from Lake Oroville in response to torrential rainfall that happened to pour down over the Sierra Nevada foothills at the same time.
Their homes were in danger of being engulfed in a wall of water after the 770ft (230m) high dam's spillways were found to be damaged.
In a statement posted on social media on Sunday afternoon, Mr Honea ordered residents to evacuate, repeating three times that it was "NOT a drill". An evacuation shelter was set up in Chico, which is north of the lake, at the Silver Dollar fairgrounds.
Initial fears of collapse were walked back yesterday before officials saw more signs today that the entire emergency spillway could fail "within the hour". Its crews plan to use helicopters to drop rocks into gouge in the emergency spillway to prevent further erosion, officials tweeted.
The earth fill dam is just upstream and to the east of Oroville, a city of more than 16,260 people. Although the dam is still standing, the erosion could undermine the spillway's structure, allowing rushes of water to wash downhill into nearby towns. On Sunday, the erosion that prompted the evacuation was caused by 6,000-12,000 cfs - less than 5 percent of the maximum cited by the officials.
One of the guardsmen on the Black Hawk used a hoist to lower down and retrieve Rodger McMurtry as he held on to a tree branch in the six-foot-deep water.
More rain is forecast for Wednesday and Thursday, leading to some concern about whether or not the damaged spillway can withstand the pressure.
California Department of Water Resources personnel monitor water flowing through a damaged spillway on the Oroville Dam in Oroville, California.
Officials have said that the order will be re-evaluated at dawn.
The primary spillway for the tallest dam in the United States is on the verge of failing.
Bill Croyle, the acting director at the department of water resources, said at a news conference that no corrective measures were taken after looking at the flow and available resources.
Butte County Superintendent of Schools Tim Taylor has called for closure of all the schools Monday except those in the Chico and Paradise district.