Pardon my imprecise use of nomenclature. I was implying that it's impossible to make a bigger drop from the water level to the outlet without lowering the outlet wrt the crest. But it is of course the net difference between the inlet and outlet elevations that drives the siphon strength.

I don't think anyone but Governments can afford enough dirt moving to make the top of the dam 33' above the desired water level.

"Live like you'll die tomorrow, but manage your grass like you'll live forever."
-S. M. Stirling
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