Staffs and Worcester Canal
I include this aqueduct mainly to illustrate the point where I feel that an aqueduct is no longer an aqueduct, but that depends on the weather!
Photo of Wolverley Aqueduct from the Captian's own collection
This aqueduct carries the Staffs and Worcester canal over a tributary of the Stour, just north of Kidderminster. In dry weather the channel is visible but at the time of my visit we were in the middle of a very wet spell (aka any British summer) it was completely submerged and operating as a sump.
Do you see my dilemma? It's not just the nature of a structure that makes it an aqueduct, it also depends on the flow of water beneath. Maybe a need a category called "seasonal aqueducts", but that's getting silly!