Posted on 02/15/2026 8:22:38 PM PST by Paul R.
Yesterday, the Colgate powerhouse pentock failed dramatically off of the Bullards Bar Reservoir right there in Yubi County, not very far from the Blanco Global Headquarters, kind of halfway between Grass Valley and the Orville Reservoir.
(Excerpt) Read more at youtube.com ...
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My summary: The penstock (basically a big pipe) leading to the powerhouse at Bullards Bar Reservoir in California failed dramatically on Feb. 13. It will take some serious work to buff this one out...
Excellent reporting and video shots from the blancolirio channel. :-)
The dam itself is ok. The powerhouse, not so much...
Penstock is not Colgate. It was logged off. Switch to Crest.
Hate to be a Monday-morning quarterback, but progress depends upon learning from our mistakes.
The video suggests perhaps there was insufficient planning for the aftermath of a catastrophic failure, with subsequent water erosion greatly increasing the damage. Every contingency cannot be addressed, to be sure; then again, the Safety Factor for Dodger Stadium’s cantilevered grandstand, in earthquake country, is 7. There will be a call for “Batter up!”, but never one for “Fans down!”
Yuba Water Agency posted a documenty on their website the day before about a 1986 flood.
Yuba Water debuts documentary, “The Day the Levee Broke,” ahead of 40th anniversary of 1986 flood
News
Posted on February 12, 2026
https://www.yubawater.org/m/newsflash/Home/Detail/402
The docunmentary
Thanks for posting - it was great to hear from Juan Browne again - I remember well his perceptive reports a number of years back when the Oroville Dam situation almost became a major disaster.
New Colgate Powerhouse
New Colgate Powerhouse, Yuba Water Agency’s biggest, houses two of the largest single-cast Pelton Wheel turbines ever built. Water carried nearly five miles from New Bullards Bar Reservoir through a 26-foot-diameter tunnel is routed down a 15-foot-diameter penstock to drive Colgate’s two powerful turbines, producing a total of up to 350 megawatts of electricity.
Interesting math question. Assuming no movement, how much water would have benn in the 5 mile long 26 foot diameter underground pipe?
Then at the rate of speed how much water flowed through the pipe before they were able to shut it off (reports don’t say how long it took to turn off)? 10 minutes, 1 hour?
Very funny. You will be sentenced to the rock pile.
(Just kidding.)
Online calculator says 5280 feet x 26 diameter x 5 = Cubic Feet = 14,016,529.78 ft³.
AI is useful for something. To understand the volume of 1 million cubic feet, consider the following points:
This volume is roughly equal to the space of 10 average-sized homes.
It can hold about 1,000 standard shipping containers.
In terms of a swimming pool, it would fill about 40 Olympic-sized pools.
14 million would be 14 homes and about 56 Olympic-sized pools or 17,000 large home swimming pools.
The speed the water was flowing would be needed to calculate the second question.
I don’t know the answer to your 2nd question, but the amount of erosion suggests quite a lot of water.
One thing I think Juan missed is that there were TWO major breaks in the penstock below the “blowout” point. Both were caused by the erosion.
As for water in the 5 mile long tunnel, if the ID of the tunnel is 26 feet, you have ~3.1416 * (13^2) * 5 * 5280 = ~14,016,562 cubic feet of water. That’s 104,861,165 gallons - if they got the water coming in shut off instantly...
Ah, your calculator used a more precise value of pi.
If we knew the typical cfm or cms that fed the power plant, we could easily calculate the additional water that entered the system before it was shut down.
Crested dam Aims at Colgate even though Gleeming review Promised Ultra-Brite Future.
Oroville, not Orville.
I thought this was a sports story
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