The submersible pump circulates the water from the basin up to the top of the waterfall. To size a pump for this project you first must determine the width and height of your waterfall as well as the head pressure it will create. As mentioned previously you can use our waterfall rule of thumb: pump 100 gph of water per inch of waterfall spillway. A waterfall that is 5’ high with a 12" spillway would need a pump that can produce a minimum of 1200 gallons per hour at 5’ of head pressure.
In general, you will need 1,500 gallons per hour (gph) for every 1-foot of waterfall discharge for an average flow. The discharge is considered where the water enters back into the pond. For example: Let’s say the width of our waterfall is 2′. This would mean we need a pump of approximately 3,000 gph.