MC - looks like you and NDG could share some stories (see his post of Mon. Feb. 13, about 1/3 of the way down the 1st page of this thread).
By the way, if my theoretical 25 ton/ 12.5 cu. yds. rock were a sphere, it would be about 8.7 ft. in diameter. It'd still fit inside a typical gon body with a foot or so to spare. That VW 'beetle' might be about the same volume, too - a little longer, yes - but for sure neither 8'-8" high nor wide.
- Paul North.
PDN: dumped 33 and 40 yd air dumps with Volkswagen sized big rip rap - Do those short cars ever gallop! (Chained the carbody on the opposite side to the rail to keep the car from derailing or jumping off the truck centerpins. And yes, managed to derail a few anyhow)
DC: It's been odd how quiet/ invisible the USACE (Army Corps) has been so far in the national press. (Blissfully ignorant newsworkers?)The Sacramento District has to be scrambling right now. https://www.facebook.com/sacramentodistrict For all the noise being made, these guys call many of the shots here, especially with dam safety.
Perhaps I missed it but: has there been any discussion or analysis regarding silt accumulation which would allow water accumulation to a higher level than designed for?
At some locations the Corps of Engineers are dredging silt accumulation from reserviors because the designed capacity can no longer be attained.
25 ton rock is about 12.5 cu. yds. To give you an idea, a cube about 7 ft. on each side would have a volume of about 12.5 cu. yds. So a 25 ton rock would fit comfortably in the width of a gondola car. But 5 of them would overload most cars: 5 x 25 tons = 125 tons = 250,000 lbs. + 60,000 lbs. tare = 310,000 lbs., so need the 4-axle car with the heaviest capacity, 315,000 lbs. ("315K" car), so 4 would be a maximum load. Even with 5, they would be only 5 x 7 ft. = 35 ft. long, which is way less than the usual length.
A boxcar with normal width doors would probably work - if you could find a forklift to lift one rock without going through the floor of the boxcar. I shudder to think what could be put into a high-cube boxcar, or on a TTX flat, or a set of double-stack well cars . . .
The Dakota and Iowa Railroad could probably ship out a unit train of big, pink rocks on short order from their quarry in Dell Rapids, SD. UP could pick it up in Sioux City, IA and send it on down the line. I wonder how you haul a 25 ton rock in a rail car. Boxcar with wide doors?
Thanks to Chris / CopCarSS for my avatar.
The wikipedia article on the dam has been edited to give a pretty good accounting of the current events.
https://en.wikipedia.org/wiki/Oroville_Dam
I tried to sell my two cents worth, but no one would give me a plug nickel for it.
I don't have a leg to stand on.
For maybe 20 - 30 years now there have been nationwide regulations requiring studying and improving the stability of dams against overtopping and seismic events. That's led to some major retrofits, including even the Conowingo Dam across the Susquehanna River here on the East Coast. There, many steel rod and grouted 'tie-backs' (more accurately, 'tie-downs') were drilled from the top of the dam down through it and anchored into the bedrock below.
erikem I suspect the state will be drawing up a bunch of new regulations about monitoring and maintaining dams as was done after the close call with the Van Norman reservoir in the aftermath of the Feb 1971 Sylmar earthquake.
I suspect the state will be drawing up a bunch of new regulations about monitoring and maintaining dams as was done after the close call with the Van Norman reservoir in the aftermath of the Feb 1971 Sylmar earthquake.
Wonder if a new rail spur will be installed to bring the huge quantities of repair materials to the site ?
Since the Oroville Dam was built 50- 60 years ago (!), design features, construction methods, on-site equipment, logistics, economics, and priorities (i.e., environment) have changed immensely. Large rip-rap rocks (>25 tons) would take unusual efforts and permits to move by highway - from where and how far away ? Thousands of cubic yards - and about twice as many tons - of other embankment fill (smaller rock, most likely) and then the materials for concrete* will all have to be moved in, plus likely some steel for new/ replacement control structures and reinforcing bars, etc.
*Cement, coarse aggregate (smallish rock), and fine aggregate (sand) - water they already have plenty of !
[Hindsight is 20-20 of course, but each major dam failure seems to have its own specific cause. This one may have been inadequate spillway design, plus recent mismanagement of the reservoir pool/ flood control storage capacity/ height/depth (too complex to explain here); erikem mentioned the seismic damage from the earthquake as it affected the Van Norman Dam; the Teton Dam failure was caused by crummy geology and inadequate preventative measures (see https://en.wikipedia.org/wiki/Teton_Dam#Cause), as was the St. Francis Dam near L.A. (see https://www.kcet.org/history-society/the-flood-st-francis-dam-disaster-william-mulholland-and-the-casualties-of-la ),etc.]
By the way, the original Johnstown Flood of 1889 was caused by erosion of the earthern dam (owned by the PRR for a while, then sold to the South Fork Club) after the spillway became clogged and the dam was overtopped . . . https://en.wikipedia.org/wiki/Johnstown_Flood
DSchmitt MidlandMike While there is a veneer of soil under the emergency spillway, its evident the core of the hill is rock, which would not erode at any alarming rate. Even at the Grand Canyon, the average downcutting rate was less than 1 foot per 1000 years. The unlined auxillary spillway was eroding at its top. The veneer of soil is apparently 30' deep at that location.
MidlandMike While there is a veneer of soil under the emergency spillway, its evident the core of the hill is rock, which would not erode at any alarming rate. Even at the Grand Canyon, the average downcutting rate was less than 1 foot per 1000 years.
The unlined auxillary spillway was eroding at its top. The veneer of soil is apparently 30' deep at that location.
There have been several questions posed about the quality of rock underlying the spillways, though more from resistance to erosion than compressive strength (which seems to be more than adequate). The channel for the main spillway had to cut through tens of feet of the bedrock, and the contractor had little problem doing that by using D-9's with large rippers (no blasting). Also keep in mind that the Feather River route was known for rockfalls.
As you said, the main spillway seems to be holding, though the Cal DWR folks are going to be watching it like a hawk.
One thing that caught my attention was realizing that the base of Oroville Dam is only 152' above msl and it is a good distance from the Sacramento River delta. Failure of the weir for the emergency spillway would have flooded a significant portion of the eastern Sacramento Valley.
Apparently, this type of catastrophic event was precisely warned about several years ago, and the experts that the State listened to said it could not happen:
http://www.mercurynews.com/2017/02/13/oroville-dam-update-evacuations-remain-in-place/
The issue is the velocity of the water coming over the top. Current design thinking would be aimed at slowing the water down as it hits the spillway (which would considerably reduce the spray you see in the photos)...Think series of "dragons teeth" or grouted large rip-rap instead of just a smooth paved apron. Drainage practical thinking and design (engineering) has evolved since the early 1960's state of the art, including the designs to control release speed of the water in a 500 year event.
MidlandMikeWhile there is a veneer of soil under the emergency spillway, its evident the core of the hill is rock, which would not erode at any alarming rate. Even at the Grand Canyon, the average downcutting rate was less than 1 foot per 1000 years.
The flow to the main spillway is controlled. Its concrete lining failed about half way down. When they closed it to invesigate the failure of the concrete lining, the water level of the lake rose and the flow started to wash out the auxillary spillway. They then reopended the main spillway, which lowered the lake level. The flow blew out the side at the damaged location, but because it is well below the top of the dam and the soil shallow over the bedrock, there is very little errosion.
It now appears, but is not certain, that repairs to the main spillway can wait untill a time when the spillway can be closed without raising the level of the lake.
Hindsight is 20 20.
It looks like the main spillway will hold up. It is, however, not certain that the lake level can be lowered enough ta accomodate water from storms and runoff coming in the next few days and weeks.
BaltACD What I can't understand - How can any engineer THINK a unfortified earthen spillway can withstand the pressure of rushing water? Didn't they ever look at the Grand Canyon? Water is the most universaly destructive force that nature presents humanity and anyone that doesn't believe it will pay the price.
What I can't understand - How can any engineer THINK a unfortified earthen spillway can withstand the pressure of rushing water? Didn't they ever look at the Grand Canyon?
Water is the most universaly destructive force that nature presents humanity and anyone that doesn't believe it will pay the price.
While there is a veneer of soil under the emergency spillway, its evident the core of the hill is rock, which would not erode at any alarming rate. Even at the Grand Canyon, the average downcutting rate was less than 1 foot per 1000 years.
1:48 pm Evacuation order changed to evacuation warning. Residents may return to homes but should be ready to leave again on short notice if the situation changes.
My home is in Marysville. The City was ordered evacuated although because of its levees (the tallest and strongest in the area) Marysville is shown surrounded by water but not subject to flooding from a spillway collaspe (unless the levees failed).
My family did not leave, but monitored the situation and was ready to go which could be done quickly since with most people gone there would be very little traffic on the roads. My home is less than 1/8 mile from EB Highway 20 which is on levee to beyond the flood danger area.
All businesses in Marysville closed. Some businesses accross the Feather River in Yuba City were open during the emergency. Apparently YC was not included in mandatory evacuation, which is strange. All of Yuba City is shown, on the map, as an area that could be flooded.
https://books.google.com/books?id=vtA6AAAAMAAJ&pg=PA1
samfp1943 Somehow, they engineered this dam, expecting that an overflow was unkilely (?), while providing it with asingle 'concreted' spillway, and an open. earthen, emergency spillway in a parallel position. As BaltACD suggested:"...How can any engineer THINK a unfortified earthen spillway can withstand the pressure of rushing water? Didn't they ever look at the Grand Canyon?.." Makes one wonder what con$traint$ were placed on the Engineering Staff, during the Dam's engineering phase; seems as if, maybe, one too many corners were cut?
As BaltACD suggested:"...How can any engineer THINK a unfortified earthen spillway can withstand the pressure of rushing water? Didn't they ever look at the Grand Canyon?.."
Makes one wonder what con$traint$ were placed on the Engineering Staff, during the Dam's engineering phase; seems as if, maybe, one too many corners were cut?
As soon as the news media catches up with this story, we are going to see a flood (maybe even a torrent) of news coverage about the background history leading up to this dam disaster. This is not what is commonly called an "act of God."​ There is also going to be a forest of finger pointing.
The terminology used has caused confusion... 'They allowed water to pass over the auxiliary spillway' (or something like that...) the key word being "allowed". I don't think they "allowed" that to occur, but rather it was a consequence of closing down the main spillway… it might have been expected, but there is no way they could have disallowed it.
Semper Vaporo
Pkgs.
blue streak 1 With some conflicting reports can someone in the know clarify. 1. We know the main spillway flume failed with a large section of concrete gone. Is there an expectation that if water were to continue down that washout that the water could undermine the original land under the flume and cause an uncontrolled release of water under the spillway super structure top ?
With some conflicting reports can someone in the know clarify.
1. We know the main spillway flume failed with a large section of concrete gone. Is there an expectation that if water were to continue down that washout that the water could undermine the original land under the flume and cause an uncontrolled release of water under the spillway super structure top ?
There certainly is a major concern about back erosion leading to failure of the spillway gates.
2. The same questions as #1 for the Auxiliary spillway dirt flume ?
The erosion for the auxillary spillway is much more serious that for the main spillway. The spillway is about 30 feet high and there is a lot of water in the lake between 871' msl and 901' msl.
It's not clear how much danger is posed by the erosion on the aux spillway, but the pictures I've seen make me very glad I'm not downstream. The sheriff made the correct call in ordering the evacuation.
3. The have been reports that the main spillway had its flow decreased. The design of the main spillway is not understood from pictures so far shown. Is it a passive spillway or does it have active gates that rise up out of spillway structure wihout any overhead superstructure ? If there are active gates how much higher could the lake be raised ?
It has active gates. Auxillary spillway limits lake elevation to slightly over 901' msl. Real question is how much lower can the lake be emptied by the main spillway.
The 'fun' began last week with the damage to the concrete on the main spillway channel. The flow through the main spillway was reduced in hopes of lessening damage and consequent erosion - reduced outflow was less than inflow, so lake level rose. Emergency spillway was topped about 8AM PST on Saturday.
4. The same questions for the aux spillway as #3 ?
Aux spillway is passive.
The really scarey part is that this is the 'tallest' Dam in this country, an earthfilled body[frortified ?], something like 3,000 feet side to side.
Somehow, they engineered this dam, expecting that an overflow was unkilely (?), while providing it with asingle 'concreted' spillway, and an open. earthen, emergency spillway in a parallel position.
Never too old to have a happy childhood!
Some info from the LA Times:
http://www.latimes.com/visuals/photography/la-me-lake-oroville-spillway-pictures-photogallery.html
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
having watched quite a bit of video on the spillway problems and having some knowledge of such things (BS in Geology) I can give at least patial answers to these.
1. There is likely to be at least some additional damage to the spillway and surrounding terrain, but the top of the spillway where it exits the lake was blasted from solid bedrock. I see no possibility this could erode in a way that could cause uncontrolled release of water. Nor (due mostly to the distance involved) can continued erosion affect the base of the dam itself.
2. I can't see enough detail in the videos to see what the concrete structure at the head of the auxiliary spillway is actually built on, so I can only say it is possible. Also water was flowing across a parking lot and down the hillside in such a way to potentially compromise the end of the concrete structure.
3. The main spillway has active gates, with lifting mechanisms in surrounding/overhead structure. The lake could be raised to the level where it is drained by the auxiliary spillway.
4. The auxiliary spillway is a long concrete wall/apron over which water spills when the lake reaches 900 feet elevation. (At a very slightly higher level water will also spill across a large adjacent parking lot.) Some videos show water pouring across the entire length of the concrete structure and from several points along the edge of the parking lot. There is no control other than the level of the lake - lake goes up; more water flows out.
Here is hoping that we may be able to understand this better.
mudchickenSam: http://www.wplives.com/frc/oroville_line_change.html Back in the day of those oddball U25C's..... I'd wait a while on the issue with the dam, or at least to the point where a real journalist apperas on the scene and shuts up the chicken little newsworkers with some real facts.
Back in the day of those oddball U25C's.....
I'd wait a while on the issue with the dam, or at least to the point where a real journalist apperas on the scene and shuts up the chicken little newsworkers with some real facts.
https://archive.org/stream/zh7californiastatew824222001calirich#page/32/mode/2up
The St. Francis dam was owned and managed by L.A. Department of Water and Power. Dam failure was caused by foundation of said dam built on ancient landslide. I remember my first grade teacher telling the class about a then new finding of the dam failure - this was about 23 years after it failed and a few miles away from the flood zone - memories were still fresh.
Issue with emergency spillway is potential undermining of spillway foundation due to erosion caused by spillwater flow. This probably could have been prevented with a concrete apron extending out a few hundred feet from the spillway. Failure of the spillway would have been a major disaster and unfortunately it doesn't look like it's completely out of the question for the near future.
I had hesitated to put the original post on the Forum, but it seemed to be a danger not only to the populations down stream, but a larger population as well...
Then I read the story on the accompaning linked site,today @ http://www.mercurynews.com/2017/02/12/oroville-dam-feds-and-state-officials-ignored-warnings-12-years-ago/
FTA:"...More than a decade ago, federal and state officials and some of California’s largest water agencies rejected concerns that the massive earthen spillway at Oroville Dam — at risk of collapse Sunday night and prompting the evacuation of 185,000 people — could erode during heavy winter rains and cause a catastrophe.
Three environmental groups — the Friends of the River, the Sierra Club and the South Yuba Citizens League — filed a motion with the federal government on Oct. 17, 2005, as part of Oroville Dam’s relicensing process, urging federal officials to require that the dam’s emergency spillway be armored with concrete, rather than remain as an earthen hillside..."
Is the State of California, so broke, they cannot, or won't. repair their critical infrastructure?
The memory flashed back to the catastrophic colapse of the St. Francis Dam in March of 1928.. That killed some 450 people. As I recall, it was located about 40/50 miles from Los Angeles...Was it not managed by some of the same State agencies (precursers?), of the current management of the Oroville Dam?
It would seem that California politicians and Legislators do not learn their History lessons..
See concurrent running Threads here, about various rail line closures in response to the current Oroville Dam overflows.
Spent summer of '69 dumping Air Dumps of fill for bank widening betterment work for CWR.Had ASAP Rush Run with ten 10 Air Dumps w/ rip rap size of Econoline Vans cushioned on ballast. Never saw scales. Saved the railway that day. Tie ends undercut already. Engr. rode across as bank sluffed below.Most cars built 1929. Similar pattern to those used in China mining videos. As Here. Older trucks, tho'. Note oil around cylinder, second car. Engineer on Left.http://www.chinesemodeltrains.com/Images/20150122.JPGWhen fill stuck as wet or muddy in car, the other side from dumping the wheels would lift off rail, then sometime wheels still on rail, dumping side, would kick out as load left carbody and down folding apron/side, the car then held upright, and derailed, only by couplers. Some cars still had U Clamps on chains, shaped like rail tongs, which hung on hooks each side of drawbar when not in use, and clamped around rail heads when dumping. Too many were forgotten when train started moving etc.Telescoping dumping pistons/cylinders would often spew oil all over. Some cars would dump en route at speed.
Some cars would not go 'Down' after dumping, side angled like a big scythe.
Three Air Lines on each end of car. Train Line, Air Line ( Ex MR on Locomotive for charging, or Signal Line on loco ) and Dump Line, smaller glad hand for dumping all cars at once, = they ALL go down the bank, at once.Mosquitoes GALORE along the Mighty Columbia, the River that power the West.Brake travel was excessive, and after a full set brake for a few miles, many wheels still cold. Had a greenhouse Jordan Diesel Hydraulic Spreader. One of the first, But it had a steam locomotive headlight.Runaway on UP with work train over 100 mph several years ago out West, killed two?Ditto Snow Plows, No More.Mountain Plow, No Visor. Used in deep hard snow. Side windows for light, and to get at pins on chains holding wing closed when not in use. Note guard bars over cupola windows.http://www.michaeltaylor.ca/non-rev/401036-mt.jpg Flatland Plow. Used in fluffyish stuff. No window guards.http://www.trainweb.org/oldtimetrains/photos/cpr_rolling/400774.jpg Double Track Plow, LEFT Hand. Rare. Baffle on Cupola keeps snow out of horns. Red Topped rod shows edge of wing when snow is flying by. Shorter wing.http://s3.amazonaws.com/rrpa_photos/61712/CP%20400799%20-1A%20Russell%20Snow%20Plow%20at%20Bensenville%20IL%201-24-98%20%201024VS.jpg
Re Plows. Usually FRONT truck was arch bar, NO brakes, NO SPRINGS. If sprung, plow front would bounce up and down re load of snow on blade. Doors on sides to access journals.
Plows derailed if dragged backwards in snow, another reason no brake rigging to front truck re rerailing, as guys had to go under there, no room on sides. H. Brake on rear truck.
The front plow was raised/lowered by compressed air, cylinder inside carbody, under heavy wire netting. Runners ran on rail head, cooled by snow, and front blade could be adjusted for rail size/height.
Headlight and inside lights ( for Train Orders, ETT. ) powered from locomotive w. jumper cable kept in box R.R Plow outside.
Trainline Hose kept in compartment w/ hatch cover inside main plow blade when plowing.
Bean Counters, indeed.Thank You.
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