aqueduct

noun3

1. •
   a man-made channel for moving water over a distance, often raised on arches like a bridge where it crosses a valley or river
2. •
   A structure carrying water over a river or depression, especially an ancient structure.

   • All the years he’d been down there in the traffic he’d taken this aqueduct for just another bridge, nothing to tell you that canal boats and waterfowl were being carried along above your head. — 2017
3. •
   A structure conveying fluid, such as the cerebral aqueduct or vestibular aqueduct.