Turning the screw can be done by a hand crank. A different design of screw pump mounts the screw inside a tube, which takes the place of the trough. In this case the tube and screw turn together to carry the water upward.
Screw pumps are very efficient ways of moving water and a number of engineers have speculated that they were used in the Hanging Gardens. Strabo even makes a reference in his narrative of the garden that might be taken as a description of such a pump. One problem with this theory, however, is that there seems to be little evidence that the screw pump was around before the Greek engineer Archimedes of Syracuse supposedly invented it around 250 B.C., more than 300 years later.