Selecting A Waterfall Pump System
April 4, 2009
One of the most overlooked aspects of building a pond is the size of the pump. It is the most important part of the waterfall, even more important than the waterfall itself because it is responsible for getting the water there. The key is knowing how much water your waterfall requires to make you happy with the results.
How To Figure It Out
To determine how much water is required to make a specific waterfall look good to you, you have to actually run it. first you have someone pour water over it, and then, when it looks right you measure it. Use a garden hose or two, pour a large pail or whatever, and adjust the flow of water over you waterfall until you are pleased. Now measure it in gallons per minute or hour. For example: if the garden hose is adjusted to make it look good and fill a (measured) five gallon pail in 40 seconds, then it is flowing at 7.5 gallons per minute – (5 gallons, divided by the 40 seconds = 5/40 gallons per second, times 60 seconds per minute = 7.5 gallons per minute). If the two gallon pail is poured over the falls and looks good when it takes 30 seconds to empty it, 2 gallon divided by 30 seconds to empty it, 2 gallons divided by 30 seconds is 2/30 gallons per second, times 60 seconds per minute, is 4 gallons per minute. If we use both a hose, which isn’t quite enough water, plus a pail, then we compute each and add the two together.
The Two Numbers You Need
You also need to know the vertical height from the surface of the water in the pond to the top of the waterfall – “how much higher are we lifting the water”. Once you know the gallons per minute and the vertical height that you’ll be lifting it, you can select a pump from the specifications. Remember that aluminum pump casing are not recommended for corrosive water like fishponds. MacArthur Water Gardens has a large supply of pumps and pump accessories to fit any need you might have.
Don’t Forget the Hose
You will also need to use big enough tubing/hose/pipe to carry that amount of water. The maximum recommended flows for hose, tubing and PVC pipes are as follows.
1/2 in 2 gpm(120gph)
3/4 in 5 gpm (300gph)
1 in 10 gpm (600 gph)
1-1/4 in 23 gpm (1380 gph)
1-1/2 in 33 gpm (2000gph)
2 in 50 gpm (3000gph)
3 in 125 gpm (7500 gph)
When in doubt, use a size that is too large, never too small.
You Have To Have Power For The Pump
The National Electric Code specifies that the outlets should usually be over four feet from the pond and covered with a weatherproof enclosure. Make sure that the electrical circuit used is protected by a GFCI (Ground Fault circuit Interrupter).
I hope this has been helpful. If you have any questions or comments please post them below.
Build Well.
