Head is often times associated with vertical lift. There are however other factors with pipe that significantly affect the performance of a pump. Pipe length and diameter are often overlooked yet extremely important data to keep in mind especially is the diameter is too small. The pump must be able to not only lift to its vertical heights but also overcome the friction loss created by the distance of the pipe. Therefore, what we in the pond and fountain industry call all these factors put together is the Total Dynamic Head. That is the total lift plus the length and diameter of the pipe. In smaller ponds friction loss is really not some much a problem, but know is an essential calculation in larger water features such as streams or fountains that have high water flow rates.
The pipe comparison chart shows how many square inches of surface area a given pipe diameter has, and points out the significant differences between even ½” increments.