No force would be required to raise or lower the level of water in the locks (and thus to raise or lower a ship in transit) other than the force of gravity. The water would simply flow into the locks from above—from Gatun Lake or Miraflores Lake—or flow out into the sea-level channels. The water would be admitted or released through giant tunnels, or culverts, running lengthwise within the center and side walls of the locks, culverts eighteen feet in diameter,
