The Romans knew precisely what angle to run water down a hill in order to get it to climb up the next hill. They also knew, or at least were aware of, the venturi effect......that was not re-discovered until the 18th century...........
http://en.wikipedia.org/wiki/Venturi_effect
I did not see any “down a hill and back up” designs in these Roman supply canals. The canals snaked back and forth along the hillsides very, very slowly always going downhill at a constant rate.
The high multi-arched “bridges” that we call aquaducts themselves are used to cross the valleys and rivers between the original water source (a lake or spring up above the town) and the final town’s discharge: a bath, fountain, or cistern/storage well.