The pool at the top of the gardens could then be released by gates into channels which acted as artificial streams to water the gardens. The pump wheel below was attached to a shaft and a handle. By turning the handle, slaves provided the power to run the contraption.
An alternate method of getting the water to the top of the gardens might have been a screw pump. This device looks like a trough with one end in the lower pool from which the water is taken with the other end overhanging an upper pool to which the water is being lifted. Fitting tightly into the trough is a long screw. As the screw is turned, water is caught between the blades of the screw and forced upwards. When it reaches the top, it falls into the upper pool.