IIRC, the “down a hill and back up” designs were primarily used around Rome to bring water into the city..........
They may be.
It would require a watertight, airtight construction completely surrounding the “pipeline” that would be very difficult.
Watertight under the canal? Sure, or at least good enouigh so leakage is low enough not to matter.
But airtight so a sufficient vacuum is created? That wasn’t what I saw on the ground. Then again, I was looking some 2000 years after they built it. About 1800 years after it was operating. 8<)
A 125 foot drop with no restrictions and a constant head pressure would give you a 4 bar, 61 psi pressure, at the end point That is around a 120 ft lift +/-, with sufficient flow you can do a lot with that.