The flow with any of these devices is a function of the volume of each bucket and the
speed at which the buckets pass across the top of the wheel and tip their contents into a
trough set inside the wheel to catch the output from the buckets. Therefore, for a given
power source and speed of operation roughly the same number of containers are
needed regardless of head. In other words, a higher head Persian wheel requires the
buckets to be proportionately more spaced out; double the head and you more or less
need to double the spacing.