Last night California officials ordered the immediate evacuation of 188,000 living in low lying areas along the Feather River, South of the Oroville Dam. This extends at least to Nicolaus about 15 miles above Sacramento.
The recent heavy rains and melting snow have increased inflow into Oroville Reservoir which was created by building a 770 foot tall earthfill dam in the Feather River Basis. Officials opened the gates several days ago to reduce the water level in the dam. This is standard procedure.
It was noticed that instead of the discharge water flowing smoothly down the main spillway it was sending hugh torrents up into the air and water was flowing over the side of spillway. When officials shutdown the flow to inspect the spillway, they found the a huge hole in the concrete spillway approximately 300 feet wide by 500 feet long by 45 feet deep. That's a big hole.
Officials were using helicopters to drop boulders into the hole. Think about the size of boulder a helicopter can fly with now think about filling a hole the size of a couple of Notre Dame Stadiums. Big hole, not so big boulders to fill it with.
With the main spillway shutdown, the water level rose in the reservoir until the water flow naturally over an emergency spillway. Now the emergency spillway isn't paved. It's an earthen slope. Earth that erodes when water at high velocity flows across it. And that's what it did. So the officials were forced to re-open up the damaged main spillway to handle some of the flow ... the rain and snow runoff are still sending 40,000 cubic feet of water per second into the reservoir, roughly refilling it at about a 40% rate of the water being discharged. So if you shut the main spillway down for repairs, the reservoir refills itself.
So last night state officials made the rare call to evacuate the downstream areas in event that further damage to the spillways could cause a 30 foot wall of water from the reservoir to flood downstream areas.
What's happening now with evacuations near Lake Oroville? Our latest - LA Times
Evacuation Immediate for Sutter County, CA
Evacuation orders remain for more than 180K as officials monitor Lake Oroville
https://www.google.com/search?q=Oro...V-75BCpRGhNEV-ZZgRF4f8Q&imgrc=wbLUjVvmHDlT4M:
Threat of Oroville spillway collapse lessens as thousands evacuate from Marysville, Yuba, Butte and Sutter counties | The Sacramento Bee
The recent heavy rains and melting snow have increased inflow into Oroville Reservoir which was created by building a 770 foot tall earthfill dam in the Feather River Basis. Officials opened the gates several days ago to reduce the water level in the dam. This is standard procedure.
It was noticed that instead of the discharge water flowing smoothly down the main spillway it was sending hugh torrents up into the air and water was flowing over the side of spillway. When officials shutdown the flow to inspect the spillway, they found the a huge hole in the concrete spillway approximately 300 feet wide by 500 feet long by 45 feet deep. That's a big hole.
Officials were using helicopters to drop boulders into the hole. Think about the size of boulder a helicopter can fly with now think about filling a hole the size of a couple of Notre Dame Stadiums. Big hole, not so big boulders to fill it with.
With the main spillway shutdown, the water level rose in the reservoir until the water flow naturally over an emergency spillway. Now the emergency spillway isn't paved. It's an earthen slope. Earth that erodes when water at high velocity flows across it. And that's what it did. So the officials were forced to re-open up the damaged main spillway to handle some of the flow ... the rain and snow runoff are still sending 40,000 cubic feet of water per second into the reservoir, roughly refilling it at about a 40% rate of the water being discharged. So if you shut the main spillway down for repairs, the reservoir refills itself.
So last night state officials made the rare call to evacuate the downstream areas in event that further damage to the spillways could cause a 30 foot wall of water from the reservoir to flood downstream areas.
What's happening now with evacuations near Lake Oroville? Our latest - LA Times
Evacuation Immediate for Sutter County, CA
Evacuation orders remain for more than 180K as officials monitor Lake Oroville
https://www.google.com/search?q=Oro...V-75BCpRGhNEV-ZZgRF4f8Q&imgrc=wbLUjVvmHDlT4M:
Threat of Oroville spillway collapse lessens as thousands evacuate from Marysville, Yuba, Butte and Sutter counties | The Sacramento Bee
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