Posted on 02/13/2017 7:18:20 PM PST by Mariner
I might add that I expect little out of the repair effort based upon what I am seeing now. A massive repair effort would involve hundreds of vehicles, equipment, trucks, cranes and the like. That is what you do when you excavate a giant hole, or place a mass foundation for a monster structure.
You have giant light towers (light plants), staging roads being graded, hundreds of trucks moving unsuitable material out and proper material in. This was my field of work and nothing like that appears to be underway because no one has been told to spend the money and make the effort.
Also, the use of geotextiles + grout is an excellent suggestion. (If they have any paper mills in the area, they discard thousands of feet of "Dryer felt" [actually super-strong resin-coated open weave fabric] that makes an excellent geotextile.) They have difficulty disposing of it, and would gladly donate & load the scrap fabric onto trucks with their own cranes...
“The critical question is “How deep does the vertical concrete face of this structure (right side) extend?” (i.e. “How deep must the backface erosion (left side) reach before water tunnels under and destroys the whole structure?)””
__________
Sounds like this in reverse:
“Model Dam Fail”
“That’s enough water to make you wonder if the entire structure is at risk of erosion.”
Over 27B gallons at 40 ft depth by 15,500acres; 620k acre-feet.
So, if a breach spills 500kcfs that’d take up to 15 HOURS at that run rate before the lake level drops low enough for it to start to throttle back, and that makes NO allowance for upstream influx during those 15 hours.
You send 500kcfs down the Feather River every second for 15 hours and there’ll be a WHOLE lotta new swampland in California.
Not sure the parking lot is an option. I think the road over to it is gone. The “emergency” overflow was down a dirt hill, and the dirt is rapidly leaving. That was the end of that road in.
http://www.freerepublic.com/focus/news/3524221/posts?page=697#697
Unconfirmed:
This comment is from arfcom’s ProFryan, who was live streaming on Periscope from the dam over the weekend.
2/14/2017 12:02:24 AM EST
All right, I just got home. Where are we at?
Clearly O town is f***ed. The latest pictures show the cracks right beneath the Espill are the deathblow. Anyone with half a brain knows that it’s not Fill it’s decomposed granite or who knows what that’s just rock sitting on top of a rock.
( The word from the people working on it who are not allowed to talk publicly is there are seven monster cracks beneath the emergency spillway )
They have a better chance of bailing out the lake with a teaspoon in mitigating this man-made disaster. It's man-made disaster due to negligence.
My gosh, terrible drought/too much rain, could that be climate change?? ;-)
Dams, bridges, underground water systems, time to get those infrastructure projects up and moving.
If the water erodes around the side of the auxiliary spillway, the whole lake could pour through there.
OMG if true! Will the people of that town get to sue corrupt moonbean? Out of his own pocket? He has oil money his dad got the deal decades ago.
Wish they could sue him personally, he knew about the dam years ago. They could have fixed it during the drought. That whole gov in cali p8sses me off so much.
4) terrible management.
When I saw they were using a H-60 Blackhawk then I knew they were not serious.
I want to see a serious effort to get large sets of siphon pipe going across that emergency spillway to get the water below the primary spillway so they can get in and get repairs started.
These people are not problem-solvers (Pioneers), they are placaters (settlers). Their job has been to maintain (sit on) a situation. They have the wrong mindset. The Sheriff probably saw the CHP video that showed all of the fresh erosion below the parking lot and had to act on very limited information. Go back and look at the pictures of Grand Teton dam and take a lesson of how quickly water erosion can get out of control.
I own a lake, it’s small, only 14 acres at 55’ deep, but I have a levy almost 300’ long with a primary and emergency spillway.
What cracks me up is the state of Indiana crawls up my butt every two years with a magnifying glass inspecting that levy and the emergency overflow trench cut through the rock. Even a small tree growing up in it, or an exposed piece of dirt without a thick layer of sod on it, and I get red flagged and fined.
Watching this unfold has been an eyeopener for me simply because how California allows a levy that has such a huge impact to be so shoddily maintained is beyond me. Had the old fart I have to deal with bi-annually on my inspections been out there there wouldn’t have been enough red flags and tape in the whole county for him to use on it.
I guess when it’s state controlled and money is involved they can tell old farts like him to shut up and go fine taxpayers on their private property and leave the state controlled levies to the “experts”.
This will turn into death by apparatchik before the end.
Any time water goes over the top of a dam it is at risk of imminent collapse due to erosion.
My hometown of Red Bluff (30 miles down I-5 from Redding) is experiencing water levels not seen since the early 1990s. The Sacramento River flow was significantly depleted since the Red Bluff Diversion Dam was removed, but is up to its old levels again.
Last I heard the release rate at Shasta Dam was 70,000 cfs, now it’s rolled back to relieve the river... quite a juggling act needed to avoid disaster. I hope the Shasta Dam is getting some serious inspections.
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