- Adding a waterfall to your pond requires a pump, a hose or pipe to move the water from the pump to the top of your waterfall, a basin to catch the water from the pump hose, and a spillway for the water to leave the basin and return to the pond. Experts recommend using flexible-ridged hose pipe because it doesn't have the flow restriction of L-bends used in rigid piping like PVC (Reference 2).
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Obtaining a pump will be the largest investment in your project. Do some calculations before shopping for a pump to figure out how many gallons your pond holds. If your waterfall design includes a stream of any length, also calculate the volume of water flowing down it.
Knowing that 7.48 gallons encompass 1 cubic foot of space, multiply the length by the width by the depth of both pond and stream, then multiply the results by 7.48 to determine total system gallons (Reference 2). A pump will need to move that number of gallons every hour. Pumps are listed with a specific gallon per hour (GPH) rating; this number is equal to the amount of water it can pump in one hour without having to raise the water above the surface (Resource 1).
The GPH rating on a pump needed for a waterfall will seem much higher than necessary, but the pump is fighting gravity and the resistance of friction caused by moving the water through a pipe. Consider that for every foot in elevation you raise the top of the waterfall above the surface of the pond, you increase the "head" rating. Maximum head rating on a pump is the maximum height the pump can pump water before the flow becomes zero. Also, every 10 feet the water travels through a pipe equates to another foot of head resistance (Reference 4). If you know the total gallons of water you need to move and the height of your waterfall design, you can look up the proper-size GPH pump for your needs.
Compare pumps if more than one fits your GPH needs. Calculate the operating cost of each pump over an assumed three- to six-year life span of running every day, all year long. Divide the operating watts of a pump by 1,000, then multiply that by 24 and 365 to find out the number of kilowatts per year. Use your local utility bill information to determine annual cost of operation, then add that to the initial price of the pump. You may find that the more expensive of two pumps can save you money over the life of the pump (Reference 6). -
Gravity is going to do most of the work in the viewable portion of a waterfall. Install the pump to the manufacturer's specifications within the pond. Run the hose to the top of the waterfall. Hiding the hose where it exits your pond may take some creative positioning of rocks, plants or orientation with regard to viewing areas. If you choose to bury the hose, be aware that leaks are more difficult to detect and repair.
If you've designed a stream, line the water's path with rubber pond lining before placing stones or other media. You may prefer to contain the water in a weir, or box, before allowing it to cascade over the spillway and into the pond. You can purchase ready-made waterfall weirs or create your own from a plastic container and a few simple hose pipe connectors (Reference 5). Connect your pump to an outdoor electrical outlet with a ground fault circuit interrupter.
