A pond pump is designed to pump water from the reservoir at the bottom of the waterfall back up to the top of the waterfall. It is important to have just the right amount of water to make sure the pump runs optimally.
- If you have too much water, it will spill over the water reservoir and make a flood outside the pond when you turn the waterfall off.
- If you have too litte water, the pump will run dry, have air pockets, or cause exessive noise, all of which can decrease the life of your pump.
How to calculate the right amount of water for your waterfall
Use this formula:
Length of waterfall x width of waterfall x (0.25 x Depth of water) = how many cubic feet of water you need running down your waterfall, also called water in motion.
Of course, we don't normally measure water in cubic feet. There are 7.48 gallons per cubic ft of water. Muliply how many cubic feet of water from the formula above x 7.48, and you will have how many gallons of water you need.
To find out how much water you need for the entire system, multiply the amount of water in motion you need x 2.5. This will give you enough water to keep the pump submerged at all times, and not have an overflow when the pump is turned off.
Here is an example:
Length = 10ft Width = 3ft Depth=.5 inch
Calculate Water in Motion: L x W x (0.25 x D) x 7.48
10 x 3 (0.25 x 0.5) x 7.48 = 28.05 gallons
Calculate Total Amount of Water: Water in motion x 2.5
28.05 gallons x 2.5 = 70 gallons
This means that you need a reservoir that can hold 70 gallons of water! For pondless waterfalls, water matrix are a great way to store larger volumes of water in a smaller footprint, which gives you more flexibility on design.