Water Resources: Hydraulics and Hydrology
A:
That's right.
Q ..
And the conditions. Are there physical conditions that prevent the use various types of
gates?
A:
No, economy is the main consideration. For example, vertical lift gates could be used for
any dam, provided the width of spillway bays are limited to 20 feet, instead of feet for
tainter gates. But the cost of using vertical lift gates would be considerably larger because
over twice as many costly gate piers would be required. On the other hand, if a spillway
located in one abutment of a dam is, say 60 feet wide, it may be more economical to use
three vertical lift gates with two gate piers than a
wide tainter gate.
What about the double-leaf lift gates? Now what are they--they're vertical
gates, right?
Yes. Double-leaf gate. I know that such gates were used by the Corps.
McNary Dam apparently has them.
McNary Dam, that's right. Well, double-leaf means that the gate is constructed with
independent upper and lower sections. As the reservoir water level rises gate operation
begins by raising the top part of the gate. If the reservoir continues to rise so large flows
go over the bottom gate leaf, then it is raised up out of the flow.
So it's sort of like a sectional lift rather than a single piece?
Right.
Okay. I was looking at this picture, and it had various things like that where more water
comes out of one gate than the other.
Yes.
Okay. Well, I learn something every time.
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