We exited the dam and entered the powerhouse via a bridge across an expanse of green grass. (See tiny bridge at far end of next shot, that's the one from the employee elevator).
Under the grass are eight 14' penstocks that provide the water to the generators. At construction the penstocks were left exposed. It was soon discovered that vibration from the water flow would require modification. Thus the tons of dirt with grass planted on top.
This diagram illustrates how a penstock enters the powerhouse. The huge water flows work with low pressure to turn the turbines.
Inside the powerhouse a glass walled gallery allows visitors an amazing look at the 8 generators that each produce 1300 megawatts.
One generator was torn down in anticipation of the installation of the new stainless steel turbine and wheel.
(All eight will eventually have the old cast wheels replaced with new stainless).
Even at Glen Canyon with the capacity to produce seemingly endless electricity, it's a WATER FIRST policy that is reflected in the logo.
My visit here was a highlight of my whole trip. Next year, Hoover Dam, and it won't be by mistake!