Grtechguy wrote: I wonder if this will change their mind about succeeding from the union with a FEMA call.
Given the recent response in other states, it might just stiffen the resolve to leave.
That is a big hole.
Grtechguy wrote: I wonder if this will change their mind about succeeding from the union with a FEMA call.
Given the recent response in other states, it might just stiffen the resolve to leave.
That is a big hole.
For some perspective, Oroville Lake is the second largest man-made lake in California. Lake Shasta is the only one larger.
In reply to aircooled:
I have no problem with the Delta Smelt issue. I accept that we are not the only species on this planet and everything plays a role in our ecosystem.
The almond farmers that are on 100+ year old water contracts are an issue that needs to be dealt with though.
Some thoughts and questions
1: This hole is in the main spillway, so as I understand the dam regulates its height by opening the spillway gates, which allows the lake to drop to the level of the bottom of the spillway, which doesn't look that tall.
2: The emergency spillway is pretty much "The wall is lower here and there's a hill on the other side", is that correct?
3: The dam itself doesn't have any way to let water through?
4: That spillway looks like the worlds best soapbox derby track, except perhaps the end, and probably also the giant hole in the middle.
5: Can't they just shut the spillway and enact some sort of super-quick repair to the ramp? I mean, it's basically has to be flat and strong, they could probably get a bunch of steel shapes and throw it on there and weld it together in like an hour if they staged everything and had it ready.
Duke wrote:Toebra wrote: If that part goes, my understanding is that it drops the lake 30 feet. We are talking about a 15,000 acre lake, so that is about 45,000 acre feet.Actually, 45**0**,000 acre feet.
You are right, my bad, so that adds up to ten times more than I thought. Acre foot is like 300,000 gallons
California secede from the US, ha, fat freakin' chance.
tuna55 wrote: Some thoughts and questions 1: This hole is in the main spillway, so as I understand the dam regulates its height by opening the spillway gates, which allows the lake to drop to the level of the bottom of the spillway, which doesn't look that tall. 2: The emergency spillway is pretty much "The wall is lower here and there's a hill on the other side", is that correct? 3: The dam itself doesn't have any way to let water through? 4: That spillway looks like the worlds best soapbox derby track, except perhaps the end, and probably also the giant hole in the middle. 5: Can't they just shut the spillway and enact some sort of super-quick repair to the ramp? I mean, it's basically has to be flat and strong, they could probably get a bunch of steel shapes and throw it on there and weld it together in like an hour if they staged everything and had it ready.
The dam itself does have water flow through it, and turbines in said holes. The spillway is for height control, as you mentioned.
Shutting the spillway pretty much immediately brings the emergency spillway into use.
In reply to tuna55:
1: This hole is in the main spillway, so as I understand the dam regulates its height by opening the spillway gates, which allows the lake to drop to the level of the bottom of the spillway, which doesn't look that tall.
---its ~770 feet tall. The powerhouse and spill way are both full open. The inflow was just huge after crazy rain and a warm spell.
2: The emergency spillway is pretty much "The wall is lower here and there's a hill on the other side", is that correct?
---yep
3: The dam itself doesn't have any way to let water through?
---Just that spillway and the powerhouse.
4: That spillway looks like the worlds best soapbox derby track, except perhaps the end, and probably also the giant hole in the middle.
---Yeah it looks live WAY too much fun 
5: Can't they just shut the spillway and enact some sort of super-quick repair to the ramp? I mean, it's basically has to be flat and strong, they could probably get a bunch of steel shapes and throw it on there and weld it together in like an hour if they staged everything and had it ready.
----Water was coming in too fast. Thats what started this issue in the first place. They noticed the hole and shut it down for a day. The runoff and rain was coming in faster than they would let out even with everything 100% open. That extra day of buildup when the spillway was closed really screwed them.
In reply to tuna55:
BoxheadTim wrote: In reply to tuna55: 1. Yep. 2. Yep. 3. IIRC there's a hydro-electric power station at the base of the dam and they're running that at full tilt already. 5. Probably not. Also, don't forget that soil around here and especially on the western side of the Sierra is pretty much saturated and not something you want to build on right now. Plus as usual, there's always the money issue...
RE 3:
Running at "full tilt" is probably not the best scenario for flowing water. Why not freewheel the turbine and just use the generator to regulate the RPM to whatever the overspeed limit for those things?
java230 wrote: In reply to tuna55: 1: This hole is in the main spillway, so as I understand the dam regulates its height by opening the spillway gates, which allows the lake to drop to the level of the bottom of the spillway, which doesn't look that tall. ---its ~770 feet tall. The powerhouse and spill way are both full open. The inflow was just huge after crazy rain and a warm spell.
No, the dam itself is 770 feet tall. The spillway looks tiny. I mean this: How much water is above the lower level of the spillway?
In reply to tuna55:
If I amk reading this right, its about 130' below the top lip?
In reply to java230:
Yup, I think that's right, so 130 feet is the maximum that they can drain the lake. I am not sure if that makes sense to me, it seems like the spillway would need to be designed to some sizable portion of the dam height, but I am not an expert, I'm just guessing.
tuna55 wrote: Running at "full tilt" is probably not the best scenario for flowing water. Why not freewheel the turbine and just use the generator to regulate the RPM to whatever the overspeed limit for those things?
I would assume the turbine has to run at a precisely set RPM to spit out 60 HZ three phase power.
This photo really helps to put things into perspective:
Last night, I read that the hole in the main spillway was 300'x500', and I'm sure that it's a lot bigger right now, so a quick patch job isn't really an option.
According to NPR they want to drop the level 50' before the next storm. I think they said the spillway is draining off 2-3" per hour at it's current rate.
In reply to EdmundColeman:
Unfortunately, people don't like to pay for prevention.
It's always easy to pull money away from the infrastructure repair budget for things like schools because THINK OF THE CHILDREN and "it's been working fine for 40 years already". By "easy" I mean "politically expedient". It's easy to blame the politicians but really, they're just listening to the braying of the people who want shiny stuff now and not dull things like concrete.
Water has awesome power. Awesome in the proper sense of the word. 150,000 cfs is a mind-boggling amount of water, it's not surprising it's tearing things up.
aircooled wrote: For those who wonder why they did not bother to fix the dam before hand. The state has priorities, and would rather spend on something like this: California's bullet train is hurtling toward a multibillion-dollar overrun, a confidential federal report warns (almost every aspect of which is a complete fail and wildly over budget... but lets push ahead shall we...)
Not trying to make light of the catastrophe in Cali, but I've got this image saved for local jokes about our Mayor, that wants high-speed rail, here.
In reply to RealMiniParker:
I probably laughed at that picture for a good minute. 
FWIW RCBS (the ammunition reloading company) is closed and I presume evacuated. They might have just a teensy bit of inventory to worry about...
In reply to Keith Tanner:
I agree.
However, apparently 10 years ago wasn't recent enough to remind people what condition our country's aging infrastructure is currently in.
I mean, there was a lot more to the I-35 bridge collapse, but still, it's bound to happen again.
Flight Service wrote:Grtechguy wrote: I wonder if this will change their mind about succeeding from the union with a FEMA call.Given the recent response in other states, it might just stiffen the resolve to leave. That is a big hole.
from what I understand, they put out a call to FEMA and have not heard a thing back.
In reply to SyntheticBlinkerFluid:
What was that bridge again? I remember a high profile collapse around that time blamed on the age of the bridge but it was really poor design and another one around the same time being overloaded past its clearly stated capacity. But neither example fit the aging infrastructure narrative. Thomas Sowell has had some very good observations concerning Californias water policies vis a vis its population growth. Ultimately this is Californias problem. Wake up calls are never pretty either at the micro or macro level. 
That's Minnesota. It had been flagged as a problem for years.
My dad used to get the FBI Law Enforcement Bulletin and I remember reading an article in there about the 1983 Mianus River Bridge collapse in Greenwich Connecticut. One of the FBI's theories was that "sludge running" was a contributing factor. Shady tanker truck drivers would take a cash payment to remove a load of toxic waste. Rather than paying the fees to dispose of it properly, they would wait for a rainy day, crack open a few valves and drive up and down I-95 until the tank was empty. They said that the corrosive waste hastened the failure of the bridge's steel substructure.
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