Erosion has created a 300-foot-deep hole in the concrete spillway of Oroville Dam and state officials say it will continue grow.
State engineers on Wednesday cautiously released water from Lake Oroville's damaged spillway as the reservoir level climbed amid a soaking of rain.
Situated in the western foothills of the Sierra, Lake Oroville is the second-largest manmade reservoir in California after Shasta....
Then along comes another required release of water moving a lot of debris and fills the channel made for allowing the turbines to run. To work on a big job like this ya gotta think big. So far it's like no big plan yet.
It's likely that the reason they needed to use the spillway was also the reason for the compromise of the spillway itself. What was unusual about this year is the heaviness of the rainfall, which, coupled with the years of drought might have allowed rain to undercut the spillway, and the rapidity of the reservoir filling up didn't even allow time to fix things. Note that this year is particularly unusual because the rainfall and reservoir filling were essentially concurrent. Typically, the reservoir level peaks after April. I can't post pictures directly into the thread from work, but the data is here:
The same site referenced above has historical data for outflows back to 1984, and shows that the last major use of the spillway was indeed in 2011, and before that, 2006
TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!
oldestguy - A massive amount of hillside got moved. They can't begin to properly move it back or clear the river within days of the spillway being shut down...
60,000cuft/day being moved is pissing around?
Seems reasonable to me.
Isn't that just a month? It would take more than a month to get open pit mine style equipment in place.
My thoughts too itsmoked - some of the big pit mining equipment may not be practical to get there, or may not be available on demand. Isn't some of it essentially assembled in place?
How about a walking dragline?
Some specs from memory of one of the first machines used at the Syncrude operation.
Working radius; 360 Feet.
Bucket capacity: 85 Cu yards, more or less.
Weight; About 7000 tons.
Height to top of boom: 214 feet.
Width: about 100 feet.
Walking speed: About 1.5 miles per day.
Prime movers: 4 x 3000 HP synchronous motors.
Production: 100,000 Yards per 24 hour day.
Energy source: 25,000 Volt trailing cable.
Assembly time: Six to ten months.
The dragline on display north of Fort Mac' could be walked down to California in about 3 years.
You would need a really long cable and may have to wait for a number of highways and bridges to be extended to over 100 feet wide.
100,000 yards per day versus the present 60,000 yards per day.
This increase in eventual production may be hard to justify.
Let's just keep doing what we are doing for the next month or so. [URL unfurl="true"]https://tce-live2.s3.amazonaws.com/media/media/121ddd79-8aeb-4e3a-8cc2-b4970e94c0ca.jpg[/url]
Bill
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"Why not the best?"
Jimmy Carter
I was thinking of equipment in the mid-range, not draglines.
Stuff like a Cat 992/3 loader and a 200-250t haul truck.
These are not uncommon, used in many smaller mine operations, some of which are not that far away.
As flat as mine work is I would think that there is idle equipment in the west.
So they are moving 2,000 cu yards a day (60k cu ft?), and they need to move 1.5 mill cuyds, that is 2 years of work.
Have they talked at all about long range plans? How they are going to re-build and reinforce the structure?
Do they have to remove ALL of the debris or will it be enough, at least in the short term, to simply dredge a channel that would allow the backed-up water to flow downstream into the main branch of the Feather River?
They're moving 60,000 CY a day. Since the spillway shutdown February 27th, they've moved 427,000 CY. That's nothing to sneeze at. I believe they are trying to dredge a channel to allow the powerplant to operate at a minimum, but are trying to move as much material in the window they have.
