By Dayleen Van Ryswyk aka “The Koi Lady”
Every season, there are new and exciting products and techniques introduced into the gardening market, and this coming season is no exception. In the fall I was at several wholesale garden shows, where I see and purchase some of the latest trends for the upcoming pond season. If the amount of manufacturers displaying their pondless products is any indication, it looks like this season will be a big one for pondless waterfalls. Though pondless waterfalls aren’t exactly new, they are getting extremely popular.
For those of you that have never heard of a pondless waterfall or aren’t really sure what’s involved in building one, read on and we’ll get you educated.
A pondless waterfall is just that. It’s a stream/waterfall without a pond. Now, some of you are asking yourselves, how you can have a waterfall without a pond. After all, the water has to come from somewhere and it has to go somewhere, how can that work without a pond? How the pondless waterfall works, is by building a waterfall in the same way you would if a pond was attached but with one difference, the water looks like it’s disappearing into the ground. This look is achieved by building a basin/reservoir lined with pond liner at the base of your waterfall. A pump vault or waterfall well (different manufacturers call them different things but they are pretty much the same thing, basically a rigid plastic vessel that your pump sits in) is placed at the bottom of the basin/reservoir, and then you back fill around the vault with rock.
What makes pondless waterfalls so popular is the fact that they are about as no maintenance as anything can get (especially with an auto-fill valve that tops up the water you’ll lose from evaporation.) Pondless waterfalls are perfect for people that travel a lot or just have a busy lifestyle. They suit families with small children that want a water feature but are worried about having a pond. They are perfect for small yards or front yards where there is no fencing. Because there is no standing water, there isn’t the liability issues commonly associated with ponds. Did I also mention that because there is no standing water, there isn’t an issue with mosquitoes either. See why they are so popular. Now, of course, if you want fish, it isn’t so exciting.
Let’s assume for a moment that I’ve just hooked you on building your own pondless water fall. Where does one start actually building one? First, as with any project, you’ll need to find out if you require a permit. After that’s taken care of, you’ll need to figure out where you would like to place it for the best visual impact. Are you wanting to build this feature for your own enjoyment or is it something to enhance your landscaping? If it’s purely for your enjoyment and that of your family, then locate the waterfall where you’ll enjoy it the most. Somewhere near where you spend a lot of time in the summer. Usually they are perfect by a patio where you can enjoy the sound with your morning coffee.
The next step would be to map out the location and take measurements of the length of the waterfall you want. You’ll also need to determine the size of the reservoir at the bottom of the waterfall that will hold the water for the feature. The way to do this is by figuring the cubic feet of water in your system, gallons aren’t important here. Most stream/waterfalls have an average water depth of 3” and most vaults are in the 2’W X 2’L X 2’D size range and the reservoir is 80% rock and 20% water. Based on this, we’ll give an example like this.
My waterfall is 20’ long and 12” wide with a depth of 3” (.25) 20’ X 1’X .25=5 cubic feet. My vault is 2’X2’X2’=6 cubic feet add the two together 5X6=11 cubic feet divide that by .2 (because there is only 20% water in the reservoir) 11 divided by .2=55.00 cubic feet divided by the depth of our vault (2’) 55.00 divided by 2.00=27.50 square feet of basin/reservoir you need to make.
If you start with a known dimension like 5’, 8’, 10 etc. the calculation goes like this.
27.50 sq ft divided by 5’=5.50’ (make the reservoir approx 5’WX6’LX2’D)
divided by 8’=3.43’ (make the reservoir approx 8’WX4’LX2’D)
divided by 10’=2.75’ (make the reservoir approx 10’WX3’LX2’D)
Just to give you an idea on approximate sizes for your reservoir, going bigger doesn’t hurt if you have the space. Going to small will mean that you may run your feature dry rather quickly.
The next step is to start digging. Once you have completed that and you have the look you’re happy with, you’ll need to measure for pond liner. When you do this, there is really only one accurate way to measure pond liner. As they say, measure twice and cut once. Take your tape measure and hold it a foot past the top of your waterfall, then follow the length of the waterfall, bending the measure over each fall until you reach the bottom, give yourself another foot down into the reservoir. Here you have two choices, either you can have one continuous piece of liner for the entire falls and reservoir, or you can do it in two pieces. If you have a spill over drop into the reservoir, then you can run two pieces of liner but if you want your falls to trickle into the reservoir, then you’re better off using one continuous piece. The down side to this is that you’ll probably have a lot of waste. Now, the extra liner isn’t really wasted because you can use the excess on top of your main liner as a cushion for the rocks you’ll be placing on it.
When choosing the pump for your project, it will depend on a few things. If you’re using flat rocks with a sharp edge like fieldstone for your spill over, then you can get away with closer to 100 US GPH (gallons per hour) per inch of spill over width. If you’re using boulder type rocks that have a more rounded edge, you’d be better advised to double that flow rate to 200 US GPH. Example; a 12” wide spill over using fieldstone would require a pump volume of at least 1200 GPH and double that for a more rounded spill over stone. When you are at your pond store buying your supplies, you’ll need to know things like head height. That’s the distance from the surface of your reservoir to the top of your feature, straight up. Also your spill over width and the size of liner you’ll need plus hose length. Something else you’ll need for your project is an underlay to protect the liner from sharp rocks under your liner. With pondless features you’ll also need underlay on top of the liner in your reservoir. This underlay, overlay is to protect the reservoir liner from all the rocks you’re going to be filling it with. This step isn’t necessary on the stream/waterfall liner, just under.
Pump vault/waterfall well
Fittings to connect everything
Ball valve to adjust pump flow rate (optional)
Rock for the pit
Spill over stones
If you don’t have enough room for a waterfall, you can make a number of other pondless features. One idea is using a nice pot with a hole drilled in the centre or a boulder that has had a hole drilled in it. I’ve even see a gorgeous clay pot turned on its side with water pouring out. The effect of the water seeming to disappear into the ground is quite stunning. The options are endless and you really are only held back by your imagination.
Don’t forget to add some low voltage pond lights for your night time enjoyment and some water plants in the pockets of water to naturalize the feature.