100 Level 102 - Chapter 1
Putting It All Together
Pumps produce both flow and pressure; flow is pretty easy to see, especially over a waterfall, but pressure is hard to visualize. The concept of Head Height is an easy way to visualize the pressure a pump produces. One Pound per Square Inch of pressure will lift a column of water 2.31 feet in the air, so a pump that has a shutoff height of 23.1 feet produces 10 psi of pressure. This matters because the higher a pump has to lift water, the less water it can deliver. It makes sense that a given pump will deliver more water to a lower waterfall than a higher one. Head Height charts or graphs tell you exactly how much volume a pump will deliver to any given height, as in “2400 GPH @ 5’ of Head”. What you’ll need to know, then, is the head of your own system. In a perfect world, the head of a system would equal the highest point above pond’s surface, so a four foot high waterfall would give you 4 feet of head, but nothing’s perfect. The water from the pump is carried to the waterfall via tubing, and the size of the plumbing really matters.
Pumps produce both flow and pressure; flow is pretty easy to see, especially over a waterfall, but pressure is hard to visualize. The concept of Head Height is an easy way to visualize the pressure a pump produces. One Pound per Square Inch of pressure will lift a column of water 2.31 feet in the air, so a pump that has a shutoff height of 23.1 feet produces 10 psi of pressure. This matters because the higher a pump has to lift water, the less water it can deliver. It makes sense that a given pump will deliver more water to a lower waterfall than a higher one. Head Height charts or graphs tell you exactly how much volume a pump will deliver to any given height, as in “2400 GPH @ 5’ of Head”. What you’ll need to know, then, is the head of your own system. In a perfect world, the head of a system would equal the highest point above pond’s surface, so a four foot high waterfall would give you 4 feet of head, but nothing’s perfect. The water from the pump is carried to the waterfall via tubing, and the size of the plumbing really matters.
