After Googling a bit, it seems that the Ancient Greeks invented the arch bridges, and the Romans modified it with a series of arches made from stone and cement to form the aqueduct.
Since Latin is basically an old italian language, it may well have been the Romans who itvented it.

via in italian means street, road, way.

Duct as an english noun means tube or passageway
Duct as an english verb means convey through a duct
which again is derived from Latin ductus 'leading' or ducere 'lead'

Unfortunatley I cant find my Latin dictionary to get more details, but I think it was the Romans at about the same time as the aqueducts.