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To: Paul R.

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?


6 posted on 02/15/2026 9:20:24 PM PST by Steven Scharf
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To: Steven Scharf

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.


8 posted on 02/15/2026 9:37:33 PM PST by Steven Scharf
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To: Steven Scharf

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...


9 posted on 02/15/2026 9:52:08 PM PST by Paul R. (Old Viking saying: "Never be more than 3 steps away from your weapon ... or a Uriah Heep song!" ;-))
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