© Emily Eng / The Seattle Times
Millions of gallons of untreated wastewater and stormwater began dumping into Puget Sound Thursday after high tides and heavy rains overwhelmed a King County wastewater-treatment center in Seattle.
Flooding at West Point Treatment Plant in Magnolia's Discovery Park caused damage that apparently fried an electrical circuit and triggered a system shutdown, a spokesman said.
That has caused the county to operate the facility much of Thursday in
"emergency bypass mode" — dumping untreated effluent directly into Puget Sound.Officials were still calculating how much untreated wastewater had flowed into Puget Sound. Doug Williams, a spokesman for the county's Department of Natural Resources and Parks,
estimated more than 150 million to 200 million gallons, with that number likely to grow.By Thursday night, Williams said the plant was partially back on line and was providing initial treatment to some of the water which had been flowing untreated into the Sound or diverted to other treatment plants.
The dumped sewage is a mix of about 90 percent stormwater and 10 percent wastewater, he said.
The county has managed to divert nearly 200 million gallons of sewage water headed for West Point to four other treatment facilities, Williams said.
Chris Wilke, executive director of Puget Soundkeeper, an environmental watchdog group, said the amount of untreated sewage dumped so far comprises about one-fifth of the typical overflow amount for the area's sewers annually.
Comment: Update: Tallest US dam in California might collapse, immediate evacuation ordered - sheriff
The sheriff in Butte County, California has ordered an immediate evacuation of all people below the damaged Oroville dam, which is feared to be in danger of imminent collapse, Reuters reports.
"Immediate evacuation from the low levels of Oroville and areas downstream is ordered. This is NOT A Drill. This is NOT A Drill. This in NOT A Drill," says the statement posted on the Butte County Sheriff's Facebook page.
The statement refers to the Lake Oroville Dam, located 105 km (65 miles) north of Sacramento.
The dam's spillway was "predicted to fail within the next hour," the California Department of Water Resources (DWR) said at around 4:30pm PST Sunday (00:30 GMT Monday).
"DO NOT TRAVEL NORTH TOWARD OROVILLE," the Yuba County Office of Emergency Services said on Facebook, urging evacuees to travel safely in all other directions and help the elderly.
Update (06:56 GMT)
At least 188,000 residents evacuated as water continues to burst through an eroded spillway - prompting fears of massive floods
Officials have ordered at least 188,000 residents near the Oroville Dam with no word yet when evacuations will be lifted because of the uncertainty about the condition of the dam's spillway, said Butte County Sheriff Kory Honea.
Releases through the dam's main, heavily damaged spillway increased to 100,000 cubic feet per second from 55,000 cubic feet per second on Sunday to try to drain Lake Oroville before a failure occurs, said the California Department of Water Resources. Water falling over the Oroville Dam's emergency spillway has stopped as Oroville lake levels dropped low enough.
Lake levels fell for the first time since Saturday and will now allow for inspection of the area. The threat of collapse due to erosion has diminished, said officials at a recent press conference.
On Sunday night, state water authorities used helicopters to drop containers of boulders to fill in the 250-foot-long, 170-foot-wide hole in the main spillway to stabilize the problem.
The cost of repairing a gaping hole in the spillway for the tallest dam in the United States could reach $200million.
Another storm is predicted to hit the area in a few days, which means California's Department of Water Resources will have to continuously monitor inflows into Lake Oroville.